Post on 15-Jul-2018
SPONSORS
Thanks to those who have helped make ICOTOM18 possible
EDAX is a leading provider of innovative materials characterization systems encompassing Energy Dispersive Spectroscopy (EDS), Wavelength Dispersive Spectrometry (WDS), Electron Backscatter Diffraction (EBSD) and X-ray Fluorescence (XRF).
EDAX products include standalone tools for EDS, EBSD and WDS, integrated tools for EDS-EBSD, EDS-WDS, and EDS-EBSD-WDS, and a free-standing micro-XRF bench-top elemental analyzer providing small and micro-spot x-ray analysis and mapping.
EDAX develops the best solutions for micro- and nano-characterization, where elemental and/or structural information is required, making analysis easier and more accurate.
EDAX designs, manufactures, distributes and services products for a broad range of industries, educational institutions and research organizations. http://www.edax.com/
Brigham Young University, Department of Mechanical Engineering. https://me.byu.edu/node
Located at the heart of both the quintessential ‘great outdoors’ and the vibrant Utah engineering community, BYU Mechanical Engineering department takes pride in preparing some of the nation’s brightest minds to pursue careers with impact. With a world-famous capstone program, and a mentoring emphasis that involves more than 70% of those undergraduates directly in faculty guided research, the department ranks amongst the highest in the nation for channeling students into PhD programs. A strong graduate program with over 120 MS and PhD students supports the ‘inspiring learning’ gained by more than 1300 enrolled undergraduates; research focuses range from biomechanics to robotics, including three decades of research in EBSD and microstructure design.
Exhibitors
Oxford Instruments NanoAnalysis provides leading-edge tools that enable materials characterization and sample manipulation at the nanometer scale.
Used on electron microscopes (SEM and TEM) and ion-beam systems (FIB), our tools are used for R&D across a wide range of academic and industrial applications including metallurgy, mining, semiconductors, renewable energy, and forensics. https://www.oxford-instruments.com/
Bruker offers a broad range of systems for EBSD, EDS, WDS X-ray spectrometry, and micro-X-ray fluorescence and nanomechanical testing technologies on the electron microscope. Bruker unique solutions for EBSD include OptimusTM for TKD, ArgusTM for microstructure visualization, Dynamic Simulation, and QUBE for advanced 3D analysis. https://www.bruker.com/
EBSD Analytical offers complete micro-structural analysis services for scientists and researchers worldwide. Our analysis services include texture, grain size, phase differentiation, grain boundary/misorientation, stress/strain, along with EDS characterization. With over 20 years experience preparing and analyzing thousands of EBSD samples, we are confident we can meet your analysis needs. Turn around times are quick and accurate results are guaranteed. Our goal is to consistently exceed customers’ expectations. http://www.ebsdanalytical.com/
BLGVantage specializes in the development of software and hardware tools for High Resolution (HR) EBSD in the field of materials science. We are interested in looking deeper at the data EBSD provides us. Our flagship software application CrossCourt4 for Strain Analysis is in use in a large number of research laboratories across the globe and supported by scientists and software engineers based in the UK, North America and Asia. http://www.hrebsd.com/wp/
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The NanoMEGAS ASTAR system for TEM allows nm resolution orientation-phase maps combined with precession electron diffraction. Applications including strain mapping (Topspin), ab initio structural determination (ADT-3D), grains statistic (ASTAR), and amorphous short range order bond length (e-PDF) characterization can be installed on all new or existing TEM microscopes. http://www.nanomegas.com/
Based in Dortmund Germany, with worldwide representation, Kammrath and Weiss is the market leader of tensile-compression-heating modules for SEM and FIB. We have been providing high-precision, electro-mechanical accessories and devices for microscopy for over 25 years. Our product line includes systems and devices in 5 major categories:
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TSL Solutions KK is based in Japan. It supports the EDAX EBSD business as an agent in Japan and the surrounding region. In addition, TSL Solutions is a manufacturer of In-Situ testing apparatuses such as tensile stages, heating stages and bending stages. Its In-Situ apparatuses are designed specifically for EBSD observation of dynamic microstructure changes. http://www.tsljapan.com/
Gatan, Inc. is the world's leading manufacturer of instrumentation and software used to enhance and extend the operation and performance of electron microscopes. Gatan products, which are fully compatible with nearly all electron microscope models, cover the entire range of the research process—from specimen preparation and manipulation to imaging and analysis. The Gatan brand name is recognized and respected throughout the worldwide scientific community and has been synonymous with high quality products and leading technology for more than 50 years. Gatan is headquartered in Pleasanton, California, U.S.A. For more information, visit: http://www.gatan.com/.
Xnovo Technology ApS, founded in December 2012, is the commercial result of more than 15 years of synchrotron and diffraction imaging research at the Technical University of Denmark.
Xnovo specializes in the development of innovative 3D X-ray imaging solutions for engineers and scientists with emphasis on 3D crystallographic imaging tools for applications within engineering, materials sciences & geosciences.
The first commercial application of Xnovo’s patent portfolio is Laboratory Diffraction Contrast Tomography (LabDCT) in partnership with Carl Zeiss X-ray Microscopy Inc. LabDCT is a unique offering for ZEISS Xradia 520 Versa X-ray microscopes providing non-destructive 3D crystallographic imaging of polycrystalline materials. http://xnovotech.com/
Throughout the world, ZEISS stands for the highest quality and reliability. Carl Zeiss Microscopy is part of the Carl Zeiss group, a leading organization of companies operating worldwide in the optical and opto-electronical industry. As the world's only manufacturer of light, X-ray and electron/ion microscopes, Carl Zeiss Microscopy offers tailor-made systems for industry, materials research and academia. A dedicated and well-trained sales force, an extensive support infrastructure and a responsive service team enable customers to use their ZEISS microscope systems to their full potential. https://www.zeiss.com/microscopy/us/about-us/welcome.html
BlueQuartz Software specializes in the development and integration of computational tools from the materials science and engineering domain into the DREAM.3D ecosystem. BlueQuartz Software's most recent activities resulted in the addition of over 100 image processing filters into the DREAM.3D data analysis package greatly expanding the range of data processing capabilities of DREAM.3D. BlueQuartz Software employs both dedicated software engineers and materials science and engineering domain experts to quickly and efficiently bring advanced computational tools to the practicing engineer and researcher. By making DREAM.3D available under a permissive open-source license BlueQuartz Software is helping researchers worldwide accelerate their data analysis. http://www.bluequartz.net/
SPONSORS
With friendly support
The Minerals, Metals & Materials Society (TMS) is a professional association that connects minerals, metals, and materials scientists and engineers who work in industry, academia, and government positions around the world. https://www.tms.org
IOP Publishing is an international, not-for-profit, learned society publisher of world-renowned journals, magazines, ebooks, conference proceedings and websites for the scientific community. These products and services enable researchers and research organisations to reach the widest possible audience for their research. We combine the culture of a learned society with global reach and highly efficient and effective publishing systems and processes. With offices in the UK, US, China and Japan, and staff in many other locations including Mexico and Sydney, we serve researchers in the physical and related sciences in all parts of the world.
IOP will publish the proceedings of ICOTOM 2017. Papers should be 6 to 8 pages in length and submitted by December 1, 2017. The papers will be reviewed and published in June 2018. For details on preparing and submitting your manuscript go to http://icotom2017.conferenceseries.iop.org.
COMMITEE
ICOTOM 18 ORGANIZATION
International Committee
Anthony Rollett USA (Chairman)
Matthew Barnett Australia
Olaf Engler Germany
Werner Skrotzki Germany
Kyuwhan Oh South Korea
Dorte Juul Jensen Denmark
Adam Morawiec Poland
Indradev Samajdar India
Satyam Suwas India
Liang Zuo China
João Quinta da Fonseca UK
Claude Esling France
Laszlo Toth France
Hirofumi Inoue Japan
Leo Kestens The Netherlands
Jerzy Szpunar Canada
Local Committee
Stuart Wright EDAX (co-chair)
David Fullwood Brigham Young University (co-chair)
Matt Nowell EDAX (co-chair)
Irene Beyerlein University of California Santa Barbara
Pamela Burnley University of Nevada Las Vegas
Sam Daly University of California Santa Barbara
David Field Washington State University
Eric Homer Brigham Young University
Oliver Johnson Brigham Young University
Mukul Kumar Lawrence Livermore National Laboratory
Asher Leff Drexel University
Rodney McCabe Los Alamos National Laboratory
Lowell Miyagi University of Utah
Tracy Nelson Brigham Young University
Srikanth Patala North Carolina State University
Warren Poole University of British Columbia
Michael Roach University of Mississippi Medical Center
Chad Sinclair University of British Columbia
Ashley Spear University of Utah
Sven Vogel Los Alamos National Laboratory
Rudy Wenk University of California Berkeley
Special thanks to the following for their assistance in organizing ICOTOM 18
Jason Murray Southwest Adventure Tours
Shandilee Richins Southwest Adventure Tours
Administrative staff of the Department of Mechanical Engineering at Brigham Young University
Staff at the Dixie Center
SCIENTIFIC PROGRAM
ICOTOM 18 SUNDAY 1
SUNDAY 8:00 Registration desk open at the Marriott Courtyard Hotel
Short Course
A Guide to Practical Crystallography and its Applications to Materials Textures
Practical Tutorial on MTEX
Instructors Marc De Graef Ralf Hielscher & David Mainprice
Room Marriott Courtyard A Marriott Courtyard B
8:30-10:30
Texture analysis of materials relies heavily on three fundamental topics: crystallography and symmetry; diffraction; and representation of orientations and rotations. In this tutorial, we will address all three topics in detail. We begin with a review of basic crystallography with an emphasis on practical approaches to crystallographic computations, both in direct and reciprocal space. Then we discuss symmetry operators, in particular the rotational symmetries of importance to materials textures. We conclude with a detailed overview of the representation of orientations/rotations in the conventional Euler representation as well as in several neo-Eulerian representations, including quaternions, Rodrigues-Frank vectors, and homochoric vectors. Participants are expected to have a basic knowledge of crystallography and diffraction.
MTEX is a very powerful Matlab toolbox for analyzing EBSD and XRD data, performing crystallographic calculations, modelling textures and analyzing plastic and elastic properties. The first half of the tutorial will introduce you into the basic concepts of MTEX while the second part will be devoted to guided exercises with the software. The part requires a laptop with Matlab version 2014b or newer installed. Prior Matlab knowledge is NOT required.
10:30-10:50 Break Break 10:50-12:30 Continuation Continuation
12:30 – 13:30 Lunch – many eateries nearby
Short Course
Practical Tutorial on Dream.3d Texture Analysis from Diffraction Data using MAUD Application Examples and Hands-on Tutorial
Instructors Michael Jackson & Anthony Rollett Luca Lutterotti & Sven Vogel
Room Marriott Courtyard A Marriott Courtyard B
13:30-15:30
The open-source software package Digital Representation Environment for the Analysis of Materials in 3D (DREAM.3D) is a freely available software tool that performs a wide range of functions for reconstructions of 3D microstructures, statistical analysis, and generation of representative volume elements. Course participants will learn the methodologies behind the analysis of 3D materials data, with a focus on practical application of workflows via hands-on tutorials. Participants will also learn how to utilize DREAM.3D to produce visualizations in the freely available software package ParaView. The goals of the workshop are to equip participants with the skills necessary to reconstruct, quantify, and analyze 3D materials data
Microstructural characterization with diffraction techniques such as synchrotron or neutron diffraction is a powerful tool in materials science, geology, and related fields of research. In this short course, we will demonstrate how the MAUD (Materials Analysis Using Diffraction) software can be used to extract texture and other microstructure parameters (phase fractions, micro-strains, domain sizes etc.) from diffraction data. The participant should have a working knowledge of diffraction techniques and crystallography. We will provide information on how to install MAUD on personal laptops prior to the tutorial and encourage interested participants to bring data of their own projects that we may be able to help with.
15:30-15:50 Break Break
15:50-17:30 Continuation Continuation
ICOTOM 18 MONDAY 2
MONDAY AM – General Sessions in Ballroom AB 8:00 Registration/Info Desk Open
8:30 – 8:50 Opening/ Logistics
8:50 – 9:20 Welcome: Professor Gerald Bryant, Dixie State University
9:20 – 9:50 Plenary: Dierk Raabe Textures Studied at Near Atomic-Scale
9:50 – 10:30 Plenary: Rudy Wenk How Textures Helped Us Understand Deformation in the Earth
10:30 – 10:40 Break
Session Deformation: Mg Rudy Wenk Recrystallization Advanced Materials Characterization
Chair(s) T Bieler & J da Fonseca
P Burnley & J Kanitpanyacharoen
F Cruz-Gandarilla R. McCabe B Lan & T Ruggles
Room Ballroom E Ballroom AB Ballroom C Sunbrook AB Entrada BC
Invited 10:40 – 11:10
H-G Brokmeier Comparison of in-situ tension and in-situ compression behavior of Mg-AZ80
S Merkel In-Situ Studies of Microstructures under Deep Earth Conditions: from Texture Analysis to Multigrain Crystallography
R Petrov Texture and microstructure of advanced high strength steel after fast heating and short annealing
J Kopeček Microstructure effects of mechanical alloying on SPS sintered Fe-Al-Si powders
M De Graef Dictionary Indexing Approach for Electron Diffraction Modalities
11:10 – 11:30
J Singh Failure behaviors of E-form and AZ31 Mg alloys: Crack initiation and propagation during mini-V-bending tests
L Miyagi Deformation and texture development in lower mantle mineral phases: What does seismic anisotropy in the deep Earth tell us about deformation?
S Janakiram Naik Texture evolution during partial recrystallization annealing in high strength automotive steels
H Mehtani Oxidation Kinetics of Steel: The Defining Role of Substrate Micro-texture
F Ram Improved spatial and angular resolution of EBSD-based texture measurement of deformed and fine-grained materials
11:30 – 11:50
L Jin Towards high ductility in magnesium alloys - the role of grain boundary misorientation and deformation compatibility
AK Mariyappan Deformation texture evolution of ω-Zr at high pressure
F Castro-Cerda The effect of the pre-heating temperature and heating rate on the textures of cold-rolled low-carbon steel
R Chulist Effect of temperature and crystallographic orientation on superelastic strain of FeNiCoAlTaB single crystals
V Mertinger Pole figure measurement methods for centerless X-ray diffractometers
11:50 – 12:10
JH Cho Texture and microstructure evolution of magnesium sheets during bending
J Gomez-Barreiro Preferred orientation in a linear viscous flow: High T torsion experiments on Diopside-Anorthite aggregates
K Nishimura Effects of initial microstructure/texture and cold-rolling reduction on texture and r-value in ferritic stainless steel sheets.
S Dhala Crystal Plasticity Finite Element Modeling of Polycrystal NiTi Shape Memory Alloy (SMA)
AD Rollett Quantification of local anisotropy and microstructure-property relationships using canonical correlation analysis
12:10 – 12:30
R Xin Variant selection of {10-12}-{10-12} double twins during the tensile deformation of Mg alloys
L Miyagi Special Presentation for Rudy Wenk
H Sandim Texture characterization of AISI 316 L steel processed by selective laser melting
S Kaboli Deformation Analysis of Alumina Compressed at High Pressure Using Electron Channeling Contrast Imaging (ECCI) and EBSD
F Brisset Geometric distortion corrections of EBSD Scans
12:30 – 14:00 Lunch: Garden Room
ICOTOM 18 MONDAY 3
MONDAY PM
14:00 – 14:40 Plenary: Ben Britton Deformation and Grain Growth of Hexagonal Metals: New Insights with
Conventional and High Resolution EBSD Techniques
14:40 – 15:20 Plenary: Tom Bieler Effects of Texture on Mesoscale Characterization and Modeling of
Heterogeneous Deformation
15:20 – 15:30 Break
Session Deformation: Ti Rudy Wenk Recrystallization Advanced Materials Characterization
Chair(s) B Diak L Miyagi & S Merkel R Petrov J Kopeček D Savage & R Hielscher
Room Ballroom E Ballroom AB Ballroom C Sunbrook AB Entrada BC
Invited 15:30 – 16:00
J Quinta da Fonseca Understanding the texture and anomalous recrystallization behaviour of warmed rolled CP-Ti
I Lonardelli Texture analysis from synchrotron and Neutron diffraction: Rietveld method applied to biological materials, commercial-pure Titanium and Shales from sedimentary basins
H Miura Effects of Nucleation at Shear bands on Texture Evolution in Cold-Rolled IF Steels
R McCabe Microstructure and Texture evolution during thermo-mechanical processing of low-symmetry metals
M Takamura In-house texture measurement using compact neutron source
16:00 – 16:20
J Jha Microstructure and texture Evolution during Thermo-Mechanical Processing of Ti-6Al-4V Titanium Alloy
L Morales Olivine-antigorite phase transformation: microstructures, phase boundary misorientation and seismic properties
A Després Texture development during static recrystallization of a warm and hot rolled ferritic stainless steels
O Van der Biest Reactive Texturing of Y-TZP and Ce-TZP in a 17 Tesla Magnetic Field
H-G Brokmeier Texture analysis with monochromatic neutrons at STRESS-SPEC
16:20 – 16:40
AD Rollett Microstructural and texture characterization and 3D modeling of Ti-6Al-4V alloys with different processing histories
D Mainprice The seismic properties of quartzites during the alpha-beta transition and the influence of texture
M Latypov Quantification of recrystallization simulation datasets by chord length distribution and principal component analysis
Y Zhang Texturation of polycrystalline NiMnGa alloys via mechanical training studied by in-situ neutron diffraction and SEM EBSD
Y Onuki Development and verification of simultaneous measurement system for texture and phase fraction by time-of-flight neutron diffraction at iMATERIA
16:40 – 17:00
K Chatterjee Study of residual stresses in Ti-7Al using theory and experiments
B Majumdar Role of Texture on Enhanced Magnetocaloric Effect in Heusler Alloys Following Stress Assisted Thermal Cycling
M Kucerakova Neutron and X-ray Diffraction Texture Analysis of Novel Al-Si-Mg Alloy
17:30 – 19:30 Reception: Marriott Courtyard Hotel
ICOTOM 18 TUESDAY 4
TUESDAY AM 8:00 Registration/Info Desk Open
8:30 – 9:10 Plenary: David Mainprice Texture Analysis of Geomaterials: A Challenge for EBSD
9:10 – 9:50 Plenary: Daniel Abou-Ras
Relationships of Microstructure and Device Performance in Thin-Film Solar Cells
9:50 – 10:10 Break
Session Deformation: Steels Cold Rolling
Rudy Wenk Recrystallization Advanced Processing Characterization
Chair(s) N Tsuji & R Ray S Vogel & L Miyagi H Sandim T Nelson S Singh & F Bachmann
Room Ballroom E Ballroom AB Ballroom C Sunbrook AB Entrada BC
Invited 10:10 – 10:40
S Suwas Texture, microtexture and mechanical properties of some Mn steels
K Kunze Quartz textures in rocks – progress in methodology, results and interpretations
A Leff Effect of recrystallization mechanisms on twin interconnectivity and corrosion resistance in FCC metals
M Hasegawa Texture Development of Alumina Coating Processed by Aerosol Deposition
B Hutchinson Evaluation of texture using laser-ultrasonics – application to steel processing
10:40 – 11:00
H Atsumi Effect of carbon addition on deformation texture of heavily cold rolled polycrystalline Fe-3%Si
L Lagoeiro The role of Dauphiné twinning on the development of quartz ribbons: implications for quartz superplasticity
G Shankar Evolution of recrystallization textures in Ni-Co alloys
T Mungole Transmission - EBSD on Ti/TiN Multilayer Thin-Films
S Singh Dynamical Simulations of Transmission Kikuchi Diffraction Patterns and Related Diffraction Modalities
11:00 – 11:20
T Morikawa Formation of High Angle Boundaries during Cold-rolling of Ti-added Ultra Low Carbon Steel
M Avalos Microstructure and microtexture characterization of avian eggshells
K-I Ikeda Effect of Sc and Zr Addition on Recrystallization Behavior and Texture formation in Al-Mg-Si alloy
P Chekhonin Inhomogeneities in strained epitaxial BaFe2As2 thin films
B Lan Texture determination using elastic waves for HCP and cubic materials
11:20 – 11:40
J Goulden Defining the mechanism for compaction of chondritic asteroids using EBSD-derived microtexture
NP Gurao Evolution of micro-texture and microstructure during conventional sintering of copper
S Pathak Strong, Ductile, and Thermally Stable Mg-Nb Nanolaminates
E Bouzy On-axis Transmission Kikuchi Diffraction in the SEM. Performances and Applications
11:40 – 12:00
A Pukenas Low-temperature EBSD investigations on a BaFe2As2 single crystal
NP Gurao Evolution of microstructure texture and mechanical behaviour of CoCuFeMnNi high entropy alloy subjected to high pressure torsion
K Thool Microtexture and Local Anelasticity Measurements: Uncharted Possibilities
12:00 – 13:30 Lunch: Garden Room
ICOTOM 18 TUESDAY 5
TUESDAY PM1
13:30 – 14:10 Plenary: Wolfgang Pantleon Evolving Deformation Structures: High-Resolution Reciprocal Space
Mapping and Orientation Distribution of Individual Grains
14:10 – 14:50 Plenary: Teryuki Tamaki Local Curvature Multi-Vertex Model on Grain Growth and Its Application
14:50 – 15:10 Break
Session Deformation: Ti Processing
Rudy Wenk Recrystallization Advanced Processing: ECAE
Characterization
Chair(s) S Mahesh M Kunz A Leff K Wierzbanowski F Ram & B Britton
Room Ballroom E Ballroom AB Ballroom C Sunbrook AB Entrada BC
Invited 15:10 – 15:40
N Tsuji Effect of Texture on Anisotropic Deformation Behaviors in Cold-rolled and Annealed Pure Ti
L Lutterotti 20 Years of Maud and the Rietveld Texture Analysis
Y Takayama Preferred orientation formation in Al-3mass%Mg subjected to shear deformation and subsequent annealing
M Janecek Influence of ECAP temperature on texture in pre-extruded AX41 magnesium alloy
D Dingley The contribution of EBSD to texture studies over the past 30 years
15:40 – 16:00
NP Gurao Effect of crystallographic texture on micro-mechanisms of deformation in monotonic and cyclic loading of titanium
S Vogel Texture Measurements by Neutron Time-of-flight Diffraction – a Powerful Tool Pioneered by Rudy Wenk
R Mathew Microstructure and Texture Evolution in Pulsed Electrodeposited Nanotwinned Copper
A Kustas Texture development in soft ferromagnetic Fe-Co-2V processed by Equal Channel Angular Extrusion (ECAE)
R Hielscher Denoising of EBSD Data
16:00 – 16:20
R Lim Microstructural Evolution of Ti-7Al Under Cyclic Loading
S Piazolo Principles of ice dynamics during crystal-plastic deformation: Linking texture, rheology and average grain size
R Ray Characteristics of Thin Cu Films Electrodeposited on Textured Ni Co Substrates
T Krajnak Texture evolution in extruded AX41 magnesium alloy severely deformed by ECAP via routes A, Bc and C
M Bieda Microstructural investigations of materials after severe plastic deformation by means of orientations mapping in TEM and SEM
16:20 – 16:40
F Wagner About the combined role of texture and grain size on hardening behavior of cp titanium sheets
R Suter Microscopic study of texture evolution under tensile strain: slip events in zirconium resolved in 3D
D Frandsen Fabricating Designed Crystallographic Textures through Heterogeneous Templated Grain Growth
H Paul The nucleation of cube grains during primary recrystallization of aluminium
S Ghodrat EBSD analysis of IF steels: comparison between 2D and 3D statistics
16:40 – 17:00 Break
ICOTOM 18 TUESDAY 6
TUESDAY PM2
Session Deformation: Steels Formability
Rudy Wenk Recrystallization Characterization
Chair(s) D Lindell T Ivankina & M Kunz A Leff F Ram & B Britton
Room Ballroom E Ballroom AB Ballroom C Entrada BC
17:00 – 17:20
JY Kang Effect of Texture on Mechanically Induced Martensitic Transformation in Duplex Stainless Steel
MD Jackson Authigenic Mineral Textures in Basaltic Tuff, Surtsey Volcano, Iceland
Y Li Relationship between Zener-Holloman Parameter, Grain Size Refinement, and Texture Evolution during Dynamic Recrystallization of AZ31B Mg…
F Bachmann Advances in 3D Grain Mapping with LabDCT
17:20 – 17:40
P Hou Role of microstructure, texture, and load partitioning in formability of TRIP steel and duplex stainless steel
R Bolmaro Study by XRD and EBSD of texture and microstructure of the eggs of Chelonoidis chilensis turtle
T Rodgers Incorporating Texture Models in Monte Carlo Simulations of Solidification
R Quey In-grain orientation spreads in deformed aluminium: 3DXRD-based measurements and finite element simulations
17:40 – 18:00
D Raabe DAMASK: Düsseldorf Advanced MAterial Simulation Kit for studying interlinked texture and plasticity in high strength steels
J Bernier Multigrain crystallography as a tool for texture analysis under high pressures and temperatures
A D Rollet Using High Energy Diffraction Microscopy (HEDM) to validate micromechanical fields calculated by FFT based method
18:00 – 19:00 Poster Session: North Lobby. See listing on pages 12-14
ICOTOM-18 TUESDAY POSTERS 7
POSTER SESSION
A: Advanced Materials & Processes A-1 Evolution of microstructure and texture in AA1100 during multi-axial diagonal forging J.-H. Shin1, M.-S. Kim1, S. C. Kwon2, S.-T. Kim2, S.-H. Lee3, S.-H. Yang3, S. Lee3, S.-H. Choi1 and H.-T. Jeong2 1Department of Printed Electronics Engineering, Sunchon National University, Sunchon 57922, Republic of Korea. 2Department of Advanced Metal and Materials Engineering, Gangneung-Wonju National University, Gangneung 25457, Republic of Korea. 3Agency for Defense Development, Yuseong-si, Daejeon 34186, Republic of Korea.
A-2 Development of micro fibril textures in melt-spun polyamide-6 fibers by transversal compression N. Wirch1, R. Ghadimi2, T. Vad3 and T.E. Weirich1,4 1Central Facility for Electron Microscopy (GFE), RWTH Aachen University, Aachen, Germany. 2Tietz Video and Image Processing Systems GmbH, Gauting, Germany. 3Institute for Textile Engineering (ITA), RWTH Aachen University, Aachen, Germany. 4Institute of Crystallography (IFK), RWTH Aachen University, Aachen, Germany.
A-3 Microstructure and Texture of Titanium grade 2 after ECAP Processing M. Wroński1, K. Wierzbanowski1, R. Z. Valiev2,3, J. Kawałko4, K. Sztwiertnia4 and E. Szyfner1
1AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, 30-059 Kraków, Poland. 2Institute of Physics of Advanced Materials, Ufa State Aviation Technical University, 450000 Ufa, Russian Federation. 3Laboratory for Mechanics of Bulk Nanomaterials, Saint Petersburg State University, Peterhof, Saint Petersburg, 198504, Russia. 4Institute of Metallurgy and Materials Science, Polish Academy of Sciences, 30-059 Kraków, Poland
A-4 Texture, microstructure and mechanical properties evolution in Fe-(x=36 and 48 wt.%) Ni alloy after accumulative roll bonding S. Boudekhani-Abbas1, K. Tirsatine1, H. Azzeddine1,2, B. Alili1, A.L. Helbert3, F. Brisset3, T. Baudin3, D. Bradai1 1Faculty of Physics, University of Sciences and Technology Houari Boumediene, BP 32 El-Alia, 16111, Algiers, Algeria. 2 Departments of Physics, University of M’sila, Algeria. 3 ICMMO, SP2M, Univ. Paris-Sud, Université Paris-Saclay, UMR CNRS 8182, 91405 Orsay Cedex, France
A-5 Characterization of Fe-Co soft ferromagnetic alloys processed by laser engineered net shaping (LENS) Andrew B. Kustas, Kyle L. Johnson, Shaun R. Whetten, Dave M. Keicher, Mark A. Rodriguez, Daryl J. Dagel, Joseph R. Michael, Nicolas Argibay, Don F. Susan Materials Science and Engineering Center, Sandia National Laboratories, Albuquerque, NM, 87123
A-6 directionally solidified non-modulated Ni54Mn24Ga22 alloys in a gradient magnetic field Long Houa, Yanchao Daia, Zongbin Lib, Yikun Zhanga, Zhongming Rena, Xi Lia,* aState Key Laboratory of Advanced Special Steels, Shanghai University, Shanghai 200072, China bKey Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang 110819, China
B: Grain Boundaries B-1 Obtaining 5D Grain Boundary Character from Surface EBSD using Band Intensity Profiles A. Amalaraj, J. Christensen, O.K. Johnson, E.R. Homer, D.T. Fullwood Brigham Young University, Provo, USA.
B-2 Effect of grain boundary engineering on the corrosion behavior of Hastelloy C-276 J. Vijay Bharadwaj1, B. Shakthipriya1 and V. Subramanya Sarma1 1Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai, India.
B-3 Microcrack Initiation and its Propagation in Cu metal films on a flexible PI substrate during cyclic-bend testing Atanu Bag, Ki-Seong Park and Shi-Hoon Choi Department of Printed Electronics Engineering, Sunchon National University, Suncheon Jeonnam, Republic of Korea
C: Characterization C-1 Texture Analysis using High Energy Material Science Beam Line (HEMS)@Petra III/Hasylab-Hamburg H.-G. Brokmeier1, Z.Y. Zhong2, M.Z. Salih1, N. Al-Hamdany1, S. Sanamar1, X. Zhou1, R. Bolmaro3, N. Schell4 1Inst. of Materials Science and Engineering, TU Clausthal, Clausthal-Zellerfeld, Germany. 2Chinese Academy of Applied Physics, Mianyang, PR China,3 Inst. de Fisica Rosario, IFIR/CONICET, Rosario, Argentina,4 Helmholtz-Zentrum Geesthacht, GEMS-Outstation DESY, Hamburg, Germany
C-2 Comparison of preferred orientation of austenite and ferrite phases of duplex steel with rolled single phase austenitic and ferritic steel J. Capek1, M. Cernik2 and N. Ganev1 1Czech Technical University in Prague, Prague, Czech Republic. 2U. S. Steel Kosice, Kosice, Slovakia.
C-3 Quantitative Fiber Diffraction: from polymers to composites L. Lutterotti, L. Fambri and M. Bortolotti Department of Industrial Engineering, University of Trento, Trento, Italy.
C-4 Practical applications of nondestructive texture measurement methods M. Sepsi, M. Benke and V. Mertinger University of Miskolc, Miskolc, Hungary.
C-5 Rotation angle optimization for texture measurement using TOF neutron diffraction S. Takajo1, 2 and S. C. Vogel1 1Los Alamos National Laboratory, Los Alamos, USA. 2JFE Steel Corporation, Kurashiki, Japan.
ICOTOM-18 TUESDAY POSTERS 8
C-6 ANDES: a multi-purpose neutron diffractometer for the RA10 M.A. Vicente Alvarez1, J.R. Santisteban1, A. Beceyro1, I. Marquez1, S. Gomez, L. Monteros, S. Pincin, A. Glucksberg, A. Coleff2 1Neutron Physics Department, Centro Atómico Bariloche, CNEA. 2Mechancial Division, Centro Atómico Bariloche, CNEA
C-7 Progress on the Development of Texture Analysis Capabilities at the HFIR and SNS at ORNL C.M. Fancher1, J. Bunn1, J. Einhorn2, C. Hoffmann, M.D. Frontzek, and E.A. Payzant1 1Oak Ridge National Laboratory, Oak Ridge, USA. 2University of Virginia, Charlottesville, USA.
D: Deformation D-1 Refining Statistical Magnesium Twinning Models via Machine Learning A.D. Orme, D.T. Fullwood, I. Chelladurai, C. Giraud-Carrier, T. Colton Brigham Young University, Provo, USA.
D-2 Simulation for texture formation of both face-centered-cubic metals and body-centered-cubic ones based on rotational symmetry among X[100],Y[010] and Z[001] principal axes H. Masui Teikyo University, Utsunomiya, Japan
D-3 Texture Changes of Electromagnetic Ferritic Stainless Steels by Compressive Deformation at High temperatures Y. Onuki1, S. Sato1, M. Uchida1, T. Naruse2, Y. Kim2, T. Ebata2, S. Fujieda3 and S. Suzuki3 1Ibaraki University, Ibaraki, Japan. 2Tohoku Steel Co., Ltd., Miyagi, Japan. 3Tohoku University, Sendai, Japan.
D-4 Texture evolution of low carbon steel wires resulted from prior drawing process Athanasios Vazdirvanidis1, George Pantazopoulos1, Marianna Katsivarda2, Avraam Mastorakis3 1ELKEME, Hellenic Research Centre for Metals S.A, 2National Technical University of Athens (N.T.U.A.) - School of Mining & Metallurgical Engineering, 3SIDENOR S.A.
D-5 The effect of damping capacity on twinned AZ31 magnesium alloy after heat treatment J.H. Kwak1, J.H. Choi1 C.Y. Kang1 and K.H. Kim1 1Pukyong National University, Busan, Republic of Korea.
D-6 Texture formation behavior during high-temperature deformation in M1 magnesium alloy K.J. Lee, M.S. Park, J.H Choi and K.H Kim Pukyong National University, Busan, Republic of Korea.
D-7 Deformation Behavior of Commercially Pure Titanium (Grade-2) under Uniaxial Compression Devesh Kumar Chouhan, Sudeep Kumar Sahoo, Somjeet Biswas Department of Metallurgical and Materials Engineering, Indian Institute of Technology Kharagpur, West Bengal-721301, India
N: Numerical Methods N-1 Texture Visualization Using Neo-Eulerian Rotation Representations P.G. Callahan1, M. Echlin1, T.M. Pollock1, S. Singh2 and M. De Graef2 1UC Santa Barbara, Santa Barbara, USA. 2Carnegie Mellon University, Pittsburgh, USA.R-1 Recrystallization Texture Evolution of Cold Rolled and Asymmetrically Warm Rolled Austenitic Stainless Steel Sheets
R: Recrystallization R-1 Recrystallization Texture Evolution of Cold Rolled and Asymmetrically Warm Rolled Austenitic Stainless Steel Sheets S. Umehara1, H. Inoue1 and J. Hamada2 1Osaka Prefecture University, Sakai, Japan. 2Nippon Steel & Sumikin Stainless Steel Corporation, Hikari, Japan.
R-2 Effect of Y contents on microstructure and texture evolutions in grain-oriented silicon steel C.S. Park, H.D. Joo, K.S. Han, J.K. Kim and J.T. Park
Steel Product Ⅱ Research Group, POSCO
Technical Research Laboratories, Pohang, Korea.
R-3 The effect of an intermediate heat treatment during thermomechanical controlled processing on recrystallization and subsequent deformation-induced ferrite transformation textures in microalloyed steels P. Gong, B.P. Wynne, W.M. Rainforth Department of Materials Science and Engineering, The University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, S1 3JD, UK
T: Transformations T-1 Effect of strain-induced martensitic transformation on texture evolution in cold-rolled Co-Cr alloys S. Sato1, M. Nakagawa1, Y. Onuki2, K. Yamanaka3, M. Mori4, A. Hoshikawa2, T. Ishigaki2 and A. Chiba3 1Graduate School of Science and Engineering, Ibaraki University, Hitachi, Japan. 2Frontier Research Center for Applied Atomic Sciences, Ibaraki University, Tokai, Japan. 3Institute for Materials Research, Tohoku University, Sendai, Japan. 4Department of Materials and Environmental Engineering, National Institute of Technology, Sendai College, Natori, Japan.
T-2 Characterization of the Factors Influencing Retained Austenite Transformation in Q&P Steels via EBSD Analysis D. Adams¹, D. Fullwood¹, J. Cramer¹, S. Irfan¹, H. Evanson¹, T. Mathis¹, S. Cluff¹, M. Miles¹, E. Homer¹, T. Brown², R. Mishra², and B. Kubic² ¹Brigham Young University, Provo, USA. ²General Motors, Warren, USA.
W: Rudy Wenk W-1 Texture and fracture anisotropy in shales deformed in a deformation DIA Jeff Gay1, Waruntorn Kanitpanyacharoen2, Michael Jugle1, Julien Gasc3-4 Tony Yu4, Yanbin Wang4, and Lowell Miyagi1 1Department of Geology and Geophysics, University of Utah, Salt Lake City, UT U.S.A. 2Department of Geology, Chulalongkorn University, Bangkok Thailand. 3Laboratoire de Géologie, École Normale Supérieure-CNRS, UMR8538, Paris France. 4Center for Advanced Radiation Sources, The University of Chicago, Chicago, IL U.S.A.
W-2 In situ texture measurements at high-pressure and high temperature using double-sided laser heating in a radial diffraction diamond anvil cell at ALS beamline 12.2.2 M. Kunz1, J. Yan2, Alastair MacDowell1, Lowell Miyagi3 and H.R. Wenk4 1Lawrence Berkeley Lab, Berkeley, California. 2UC Santa Cruz, Santa Cruz, California. 3University of Utah, Salt Lake City, USA. 4UC Berkeley, Berkeley, California.
ICOTOM-18 TUESDAY POSTERS 9
W-3 CPO patterns of an upper crustal shear zone – examples from the Lancinha Fault System, southern Brazil T. Conte1, G.C.G. Cavalcante1, L.E. Lagoeiro1, C.S. Silveira1, K.T. Pesch1, and R. Santos1. 1UFPR – Universidade Federal do Paraná, Curitiba, Brazil.
W-4 Microscale strain partitioning during high-temperature deformation of plagioclase: an example from gabbro-norite of the Barro Alto Complex, Brazil central C.S Silveira¹, L.E. Lagoeiro¹, G.C.G. Cavalcante¹, P.F. Barbosa², F.O. Ferreira³, T. Conte¹, R. Santos¹ M.T.F. Suita4 ¹Universidade Federal do Paraná, Curitiba, Brazil; ²Univesidade de Brasília, Brasília, Brazil;³ Universität Bayreuth, Bayreuth, Germany ; 4Universidade Federal de Ouro Preto, Ouro Preto, Brazil.
W-5 Application of the Elasto-Viscoplastic Self Consistent (EVPSC) code to modeling texture and lattice strain evolution in periclase
F. Lin1, N. Hilairet2, S. Merkel2, J. Immoor3, H. Marquardt3, C. Tomé4 and L. Miyagi1 1Department of Geology and Geophysics, University of Utah, Salt Lake City, 84112, USA. 2Unité Matériaux et Transformations, Université Lille 1 - CNRS - ENSCL, Villeneuve d'Ascq, France. 3Bavarian Research Institute of Experimental Geochemistry and Geophysics, University Bayreuth, 95440 Bayreuth, Germany. 4Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
W-6 Deformation of two-phase polycrystals under high pressures: effect of phase proportions on in-situ textures and stress partitionning in olivine + antigorite N. Hilairet1, T. Ferrand2, P. Raterron1, S. Merkel1, A. Schubnel2, J. Guignard3*, C. Langrand1, W. Crichton3 1CNRS - Université de Lille - ENSCL, 59000 Lille, France. 2CNRS - ENS, 75005 Paris, France. 3European Synchrotron Radiation Facility, 38000 Grenoble, France. *now at Observatoire Midi-Pyrenées, 31400 Toulouse, France
ICOTOM 18 WEDNESDAY 10
WEDNESDAY AM 8:00 Registration/Info Desk Open
8:00 - 8:30 Video Presentation: Peter Bunge
8:30 - 8:50 Bunge Award Presentation
8:50 - 9:30 Awardee Presentation
9:30-9:40 Break
Session Deformation: Al Rudy Wenk Phase Trans. Advanced Proc.: ARB Characterization
Chair(s) G Winther & S. Suwas L Miyagi & P Burnley L Kestens & T Tomida M Hasegawa R Bolmaro & R McCabe
Room Ballroom E Ballroom AB Ballroom C Sunbrook AB Entrada BC
Invited 9:40 – 10:10
K Marthinsen Evolution of deformation texture during flat profile extrusions and its understanding by FEM and crystal plasticity modelling
C Tomé A trip with Rudy: from calcite to quartz
T Tomida Variant selection mechanisms and quantitative prediction of transformation textures in steel
K Verstraete Study of the texture developed by ARB and CARB processes on an AA5754/AA6061 composite
T Ruggles Concurrent in situ HREBSD and HRDIC analysis of an AlCu oligocrystal using selectively electron transparent microstamping
10:10 – 10:30
B Diak Rolling Texture Development in Aluminum-Zinc Solid Solutions
R Lebensohn 20 years inspired by Rudy Wenk’s challenges to model texture, microstructure and anisotropy of geomaterials
S-J Park β-Mn transformation and orientation relationship in austenite-based FeMnAlC low-density steel
DJ Savage Texture evolution in accumulative rolled bonded Mg-Nb composites from polycrystal to single crystal layers
D Kim Effect of grain orientation on hydrogen embrittlement of high manganese steel
10:30 – 10:50
M Kobayashi Investigation of inhomogeneous deformation and microstructure during cold rolling in Al-Mg alloys by using 3D marker tracking method
W Skrotzki Texture formation in ionic crystals with rock salt structure
C Ranger Austenite Reconstruction Elucidates Prior Grain Size Dependence of Toughness in a Low Alloy Steel
H Inoue Texture and Microstructure of Laser Butt-Welded AZ61Mg/Ti clad sheet
T Sano 3D EBSD Characterization of Al5083 Spall Damage
10:50 – 11:10
NP Gurao New insights on modeling deformation texture and yield strength anisotropy in age hardenable Al-Mg-Si alloys
N Barton A Method for Including Diffusive Effects in Texture Evolution
L Kestens Variant Selection at Parent Phase Grain Boundary Nucleation
During -to- Phase Transformation in Low Carbon Steel
K Tanaka Relationship between Initial Hydrogen Absorption Properties and Microstructures of Mg/Cu Super-Laminate Composites with Different ARB Cycles
S Saimoto Crystal Orientation Examination of Patterns Formed by Micro-indentation of Cube-textured Aluminum Foil Using SAXS and Temperature Changes
11:10 – 11:30
W Tayon Impact of Texture on Anisotropy and Delamination Cracking in Al-Li Alloys
L Morales Fabric Transitions in Quartz via Visco-Plastic Self-Consistent Modelling: Axial Compression and Simple Shear under evolving Strain
S Cluff Crystallographic Reconstruction of Parent Austenite Twin Boundaries in a Lathe Ferritic Steel
J Scharnweber Influence of Texture on Layer stability in Ti/Al ARB Composites
R Bolmaro Study of the microstructure of a cold rolled interstitial free steel through X-Ray Diffraction and EBSD
11:30 – 11:50
S Merkel The Androgynous Twins of Zinc
T Nguyen-Minh Reconstruction of austenite microstructures in steels by global optimization of misorientation functions
M Knezevic Deformation behavior and strength of bulk Zr/Nb nanolayered composites
A Godfrey (invited) Characterization of local plastic strain during deformation from EBSD data – limitations and possibilities
12:45-21:00 Excursion to Zion National Park & Conference Banquet
ICOTOM 18 WEDNESDAY 11
WEDNESDAY PM EXCURSION TO ZION NATIONAL PARK & BANQUET On Wednesday afternoon we will visit Zion National Park and have our Conference Banquet in Springdale at the mouth of Zion
Canyon. Buses will depart for Zion NP from the Hotels and the Dixie Center. The buses will arrive at the Zion NP Lodge at
approximately 2:00PM. From the Zion Lodge you will be able to explore Zion canyon.
Southwest Adventure Tours will have guides who will lead interpretative walks/hikes to the following trails: Emerald Pools, Weeping
Wall, River Walk/Zions Narrows, Kayenta Trail. Our guides will be arranged in groups of Active (Red Lollypop Stick) (3 to 5 mile hike),
Moderate (Blue Lollypop Stick) (1 to 3 mile hike), and Scenic (Green Lollypop Stick) (less than 1 mile of walking). They will organize
on the front lawn of the Lodge in groups.
Zion National Park has shuttle busses arriving at 9 stops in Zion National Park every 7 to 15 minutes. This is the only way to move
around the park other than walking. Stop 5 is Zion Lodge. Stop 1 is at the Visitors Center and if you wish to stroll around the small
town of Springdale and the souvenir shops you can use this stop.
All guests are free to explore the park on their own. For those not interested in hiking or walking on the trails with our guides, you
can just ride the shuttle up and down the canyon for a few hours and enjoy the beautiful views or stop and hike on your own.
Please use the information on this link to plan what you would like to see and do in Zion National Park.
https://www.nps.gov/zion/learn/news/upload/tear_sheet_9-30-web-saa.pdf. This document has basic information about hikes and
walks that are available in the park, a basic park map, shuttle stop information, and a few other details to help you plan ahead.
At 5:30 PM to 6:30 PM the busses will depart from Zion Lodge to Switchback Grill where the conference banquet will be held. Each
bus will depart when full. You are not required to ride on the same bus you came from St George on to travel from Zion Lodge to the
Switchback Grill.
The buses will depart at 8:00 PM from the Switchback Grill and arrive at approximately 9:00 PM at the hotels and Dixie Center.
Some notes from Utah native Stuart Wright:
One of the famous hikes in all of America’s southwest canyon country is the Zion Narrows. You can hike about a mile up the canyon on a paved trail (Riverside Trail) but then the canyon narrows and you have to get wet to go any further. There won’t be enough time for you to hike all the way to the top of the narrows and out of the canyon but a hike up the river for even an hour is a great experience. You will get wet hiking the narrows and a hiking staff or trekking pole is helpful to navigate the slippery rocks in the riverbed. While there are boots specifically designed for canyoneering I usually just wear an old pair of tennis shoes. I do not recommend hiking in sandals.
If you do choose to do this hike you will want to bring an extra pair of shoes, socks and pants to change into after the hike as well as a sweatshirt or coat as the water is cold and the canyon is always cool even on hot summer days. You can rent trekking poles for this hike from the guide for $5 per pole. Payment can be made in cash to the guide.
Another famous hike in Zion is Angel’s landing which is very steep. The final portion of the trail is a narrow ridge line with sheer drops offs of over 1000 feet on either side. But you are rewarded with some amazing views. It is a very strenuous trail and it would be extremely difficult to do in the few hours we have in the park before dinner (and dark). If you want to do this trail I recommend coming a day early to the conference or staying a day later. You could contact Southwest Adventure Tours for transportation options.
ICOTOM 18 THURSDAY 12
THURSDAY AM 8:00 Registration/Info Desk Open
8:30 – 9:10 Plenary: Lionel Germain Advanced Parent Reconstruction: An Efficient Tool to Optimize TMTs by a
Better Control of the Parent and Subsequent Inherited Microtexture
9:10-9:50 Plenary: Chris Schuh The Texture Between the Grains: Statistics of Grain Boundaries and Grain
Boundary Networks
9:50-10:10 Break
Session Deformation: Advanced Materials
Deformation: Steels Hot Rolling
Phase Transformations Advanced Processing: Additive Manufacture
Grain Boundaries
Chair(s) P Van Houtte & F Wagner
B Hutchinson & W Pantleon
Y Zhang T Nelson S Patala
Room Ballroom E Ballroom AB Ballroom C Sunbrook AB Entrada BC
Invited 10:10 – 10:40
KVM Krishna Role of crystal orientation on deformation of Zr: A Molecular dynamics study
D Lindell Texture evolution of duplex stainless steel UNS S32205 under hot working conditions
P Yang Analysis of texture memory, surface-effect-induced transformation texture and variant selection in low graded electrical steels
A Rollett Anisotropy and Microstructure in 3D Printed IN 718
G Rohrer Grain Boundary Texture, Energy, and Curvature as a Function of Lattice Misorientation and Grain Boundary Plane Orientation
10:40 – 11:00
M Ito Texture evolution modeling of Ni alloys by crystal plasticity including twinning
T Toyoda Texture evolution after dynamic recrystallization in Fe-Mn-Si steel
A Tiamiyu Texture memory in AISI 321 austenitic stainless steel
S Vogel In-situ Investigation of Microstructure Evolution during Annealing in Ti-6Al4V Alloy Produced by Additive Manufacturing
E Homer Grain Boundary Plane Structure-Property Relationships and Fundamental Zones
11:00 – 11:20
JP Escobedo Texture evolution in clock-rolled Zr during dynamic extrusion
S Suzuki Texture Changes of Electromagnetic Ferritic Stainless Steels by Compressive Deformation at High temperatures
MA Vincent Alvarez Crystallographic Texture and Microstructural changes in a weld of two Zry-4 plates: Variant selection Model
A Rollett Effect of Microstructure and Texture on the Elasto-viscoplastic Deformation of Dual Phase Titanium Structures
N Mavrikakis Segregation Affecting the Evolution of Primary Recrystallization Textures in a Ternary Fe-Si-Sn Alloy
11:20 – 11:40
B Kania Texture as a guideline for XRD residual stress investigation
C-T Nguyen The effect of cold work on the texture of a Zirconium alloy after fast β-cycling
C Goulas Texture development in steel components produced by Wire Arc Additive Manufacturing
C Kurniawan Inferring Grain Boundary Structure-Property Models from the Effective Properties of Polycrystals via Inverse Problem Theory
11:40 – 12:00
Y Dai Martensitic transformation, twin boundary and phase interface mobility of directionally solidified Ni-Mn-Ga alloys during compression by EBSD tracing
C Daniel Texture Evolution during Hot-Rolling of Dual Phase Zirconium Alloys
S Ghorbanpour Role of texture in tensile, compressive, cyclic, and fracture behavior of direct metal laser sintered Inconel 718
J Bair Mechanisms of Grain
Growth in -7 and -9 Grain Boundaries with Mixed Mobility Trends
12:00 – 13:30 Lunch Garden Room
ICOTOM 18 THURSDAY 13
THURSDAY PM1
13:30 – 14:10 Plenary: Sivasambu Mahesh A Model of Grain Fragmentation and Microtexture Evolution During
Plastic Deformation
14:10 – 14:50
Plenary: Brad Wynne & Matthew Thomas The Evolution and Quantification of Preferred
Crystallographic Orientations in Wrought Titanium Alloys Using Traditional and Emerging
Technologies
14:50 – 15:10 Break
Session Deformation: Modelling
Deformation: Torsion Phase Transformations Advanced Processing: FSW
Grain Boundaries
Chair(s) H Garmestani L Toth L Germain S Biswas E Homer
Room Ballroom E Ballroom AB Ballroom C Sunbrook AB Entrada BC
Invited 15:10 – 15:40
G Winther Measured resolved shear stresses and active slip systems in austenitic steel
I Samajdar Microstructural Engineering in Pearlitic Steel Wires
Y Zhang Formation of microtexture induced by β to α transformation in a metastable β Ti alloy
T Nelson Texture evolution in flash and weld zone of friction welded 718 superalloy
R Ray Role of CSL Boundaries During Cold Rolling and Annealing of an Interstitial Free Steel
15:40 – 16:00
NY Juul Comparison of measured lattice rotations of individual grains with crystal plasticity simulations
S Naghdy Reciprocal effect of texture evolution and grain fragmentation during High Pressure Torsion processing
D Solas Variant selection in alpha/beta Ti alloy
J Zhang Using EBSD in the characterization of heterogeneous microstructure created in high speed FSW Al…
S Patala The Representation of Grain Boundary Texture Using Hyperspherical Harmonics
16:00 – 16:20
E Zepeda-Alarcon Texture Development in Two-Phase Mineral Aggregates: Modeling Plastic Deformation with Finite Element Methods
H-G Brokmeier Texture gradient in extruded Mg-alloys versus extruded Mg-Al composites
S Niezgoda Probabilistic methodology for analyzing and reconstructing parent microstructures from EBSD maps of transformation products
R Fonda Friction Stir Weld Textures and their Implications on 3D Material Flow
S Xia Grain orientation statistics of grain-clusters and the propensity of multiple-twinning during grain boundary engineering
16:20 – 16:40
P Van Houtte Statistical models for deformation texture prediction using vortex-type accommodation of local strain…
M Latypov Hierarchical data-driven models for texture evolution in advanced multiphase materials
S Roy Orientation dependent spheroidization response and α-phase texture evolution during… sub β-transus annealing of Ti…
FC Liu Texture evolution during friction stir welding of austenite stainless steel
E Homer, S Patala, G Rohrer, C Schuh & D Field Panel Discussion: Current status and future directions of grain boundary science and engineering 16:40-
16:50
16:40 - 17:00 Break
ICOTOM 18 THURSDAY 14
THURSDAY PM2
Session Deformation: Modelling
Deformation: Damage & Fracture
Numerical Methods Adv. Processing: Asymmetric Rolling
Grain Boundaries
Chair(s) R Lebensohn Y Wang M Knezevic H-G Brokmeier G Rohrer
Room Ballroom E Ballroom AB Ballroom C Sunbrook AB Entrada BC
Invited 17:00 – 17:30
L Toth Revealing deformation heterogeneity from texture modeling
S Suzuki Mechanical damage evaluation by using EBSD measurement
A Morawiec Parameterization of rotations in reference frames with redundant crystallographic axes
A Kliauga Experimental and Numeric Analysis of Strain and Texture of Asymmetric Rolled AA1050 Al
D Field Excess Dislocation Density near Boundaries as a Function of GB Texture
17:30 – 17:50
J Sidor Texture evolution in Al alloys: crystal plasticity and continuum mechanics based modelling…
B Shakerifard Damage initiation mechanisms under static and dynamic loading conditions in bainitic steels
A Creuziger Systematic bias effects on phase fraction measurement due to texture
S Dhinwal Texture and microstructure development in warm asymmetric rolled extra low carbon steel
L Hansen Characterizing GB Dislocation Interactions though HR-EBSD and Machine Learning
17:50 – 18:10
NP Gurao Crystal plasticity simulations of rolling texture evolution in two phase tungsten heavy alloy
C Kantzos Evaluating the Role of Texture on Surface Roughness Induced Stress Concentrations
T Critchfield Comparison of Representative Volume Elements for Grain Boundary Networks and Textures
K Wierzbanowski Modification of Texture and Microstructure of Polycrystalline Copper after Asymmetric Rolling
H Pirgazi Study of GB Character distribution in Annealed and Deformed Al by 3D EBSD
18:10 – 18:30
W Mao Intergranular interactions of metals during deformation and corresponding prediction of deformation textures
S Wright EBSD Observations of Fatigue Crack Propagation in Ni Alloy
KS Sridhar Quantification of Uncertainties in Pole Figure Analysis
M O'Brien Characterization of Grain Boundary Cracking Susceptibility in Pipeline Steels using EBSD
ICOTOM-18 FRIDAY 15
FRIDAY 8:00 Registration/Info Desk Open
8:30 – 9:10 Plenary: Yadong Wang Grain-Orientation-Dependent Fatigue Damage in Polycrystalline Materials
9:10 – 9:50 Plenary: Sandra Piazolo Making and Breaking of Minerals, Rocks and Planets: A Textural Perspective
9:50 – 10:10 Break
Session Deformation: Steel Processing
Recrystallization Numerical Methods Advanced Processing: Forging & Extrusion
Advanced Engineering
Chair(s) K Marthinsen & R Fonda
R McCabe O Johnson H Inoue T Rollett
Room Ballroom E Garden Room Ballroom C Sunbrook AB Entrada BC
Invited 10:10 – 10:40
A Kaijalainen Development of crystallographic texture under shear strain in ultrahigh-strength strip steels
Y He Effect of Annealing Temperature on the Texture and Magnetic Barkhausen Noise of a Non-Oriented Electrical Steel (0.88 wt% Si) after Inclined Cold Rolling
M Knezevic Spectral database constitutive representation within finite element and spectral micromechanical solvers for computationally efficient crystal plasticity modelling
S Biswas Microstructure and texture evolution during modified multi-axial forging of Magnesium alloy Mg–3Al–0.4Mn
H Garmestani Material Forensics
10:40 – 11:00
S Vogel Effect of Processing Methods on Texture Evolution and Recrystallization Studies on 14YWT Nanostructured Ferritic Alloys
F Cruz-Gandarilla Study of the recrystallization kinetics in Fe3%Si steels during the 1st recrystallization using misorientation derived parameters (EBSD) in the CGO process
S Singh A Model Based Iterative Reconstruction Algorithm for Pole Figure Inversion
X Bai Characterization of microstructure and texture in 6013 aluminum alloy after large strain extrusion machining process
K Cho EBSD Analysis of Pt-20Ir Wire as Lead Conductor in Implantable Medical Device
11:00 – 11:20
S Takajo Spatially resolved texture and microstructure evolution of gas gun deformed SUS304 steel using neutron diffraction
M Mehdi Texture Evolution of a 3.2 wt% Si Non-Oriented Electrical Steel during Hot Band Annealing
M Zecevic Mean-field modeling of recrystallization textures
M Jamalian Microstructure and Texture Evolution of Magnesium alloy after Shear Assisted Processing and Extrusion (ShAPE).
A Schwedt Recrystallization and crystal growth phenomena during Rolling Contact Fatigue and White Etching Crack formation of AISI 52100 bearings
11:20 – 11:40
E Vakhitova Texture Evolution Analysis in Oxide Dispersion Strengthened Ferritic Steel Transformed by a Tube Pilgering Process
R Suehiro Effect of solute Sn on the evolution of primary recrystallization texture in 3% Si-Fe
H-G Brokmeier Estimation of the orientation distribution function using incomplete sets of pole figures data
J Chen Texture development in Al-Mg-Si alloys extruded through porthole die
D Guan Individual effect of recrystallization nucleation sites on texture weakening in a magnesium alloy
11:40 – 12:00
R Bolmaro EBSD analysis of orientation gradients at grain boundaries
T Kataoka Influence of cold rolling reduction on secondary recrystallization textures in Fe-3%Si sheet
S Niezgoda Application of the symmetrized Bingham distribution and other parametric distributions for the modelling of texture uncertainty
A Jarzębska Synergic effect of Mg addition and hydrostatic extrusion on microstructure and texture of biodegradable low-alloyed zinc
E Hoar Materials-Affected Manufacturing: Inverse Model for the Simulation of Texture Evolution in Ti64 through Turning
12:00 – 12:30 Closing Remarks – Garden Room
ABSTRACTS
ABSTRACTS MONDAY AM - PLENARIES 17
MONDAY AM PLENARY SESSION
Textures studied at near atomic scale D. Raabe, M. Herbig, B. Gault , A. Stoffers, Y. Chang, A.J. Breen, L. Morsdorf, M. Yao, C.H. Liebscher, C. Scheu and G. Dehm Max-Planck-Institut für Eisenforschung, Düsseldorf, Germany.
Crystallographic texture phenomena in materials occur and matter over practically all length and time scales. This lecture presents recent insights
on texture effects at the near atomic scale. Specific attention is placed on such phenomena where the link between crystallographic texture and
local compositional effects plays a role. Corresponding experiments have been conducted using correlative electron microscopy in conjunction with
atom probe tomography on the one hand and atom probe crystallography on the other hand. In the former case joint crystallographic and chemical
information is obtained by conducting electron microscopy directly on atom probe tips prior to field evaporation and mass-to-charge spectroscopy.
In the latter case crystallographic analysis is conducted directly on atom probe data, exploiting field desorption and evaporation anisotropy effects.
Examples are presented from different functional and structural materials such as solar cells, hydrides and steels.
How textures helped us understand deformation in the Earth H.-R. Wenk Department of Earth and Planetary Science, University of California, Berkeley, USA.
The most visible impact of modern texture analysis has been in materials science, improving the quality of metallic alloys and epitaxial films. It has
also added tremendously to advance our understanding of deformation processes in the Earth. The term “texture” was first introduced in the 1833
textbook by the Belgian geologist D’Omalius d’Halloy to describe preferred orientation of crystals in rocks. With new analytical methods such as
neutron and synchrotron X-ray diffraction as well as EBSD we can now quantify textures in a way that was unthinkable 20 years ago and, advancing
sophisticated modeling methods, crystal alignment can now be predicted for a wide range of conditions, including plasticity, recrystallization, even
for complex polyphase materials such as most rocks. An example is the rock slate, composed mainly of quartz and mica. Texture analysis revealed a
texture strength in excess of 195 m.r.d., a new record, and this is not close to a single crystal but a very fine-grained polyphase aggregate. Similar
rocks that cover large volumes in sedimentary basins are shales with weaker but significant textures, creating macroscopic anisotropy that is highly
significant for seismic exploration of hydrocarbon deposits and has raised a lot of interest. In many ways the most fascinating application is the
deep Earth where geophysicists have documented significant anisotropy for propagation of seismic waves, particularly in the upper mantle (~100-
250 km), the lowermost mantle (~2800-2900 km) and the innermost core (~5000-6300 km). Geodynamicists suggest large-scale convection in much
of the deep Earth, with very significant strain. If we know deformation mechanisms of the mineral components, which we can approach with
ultrahigh pressure deformation experiments (such as diamond-anvil cells) or theoretical models, then we can predict crystal alignment and apply it
to the geodynamic strain evolution. This has been done for the upper mantle where the main phase is olivine Mg2SiO4, to the lowermost mantle
with a mixture of MgSiO3 “postperovskite” and MgO periclase, and the inner core composed of hcp iron. Some examples will be shown that
demonstrate that alignment of crystals during convection is the likely cause of seismic anisotropy. Such research that links microscopic processes at
the crystal scale with large macroscopic properties at the 1000 km scale, has only become possible through close collaborative interaction of
geoscientists and materials scientist, and meetings such as ICOTOM have been invaluable in establishing such contacts.
ABSTRACTS MONDAY AM - DEFORMATION 18
Symposium D: Deformation Textures Session: Magnesium
Symposium Chairs:
Professor Chadwick Sinclair, Department of Materials Engineering, University of British Columbia
Professor Warren Poole, Department of Materials Engineering, University of British Columbia
Dr. Samantha Daly, Department of Mechanical Engineering, University of California, Santa Barbara
Comparison of in-situ tension and in-situ compression behavior of Mg-AZ80 H.-G. Brokmeier1, N. Al-Hamdany1, R. Bolmaro2, A. Roatta2, E. Benatti2, M. Avalos2, V. Ventzke3, N. Schell4 1Inst. of Materials Science and Engineering, TU Clausthal, Clausthal-Zellerfeld, Germany. 2 Inst. de Fisica Rosario, IFIR/CONICET, Rosario, Argentin. 3 Helmholtz-Zentrum Geesthacht, Geesthacht, Germany. 4 Helmholtz-Zentrum Geesthacht, GEMS-Outstation DESY, Hamburg, Germany
Tension-compression behavior of Mg and Mg-alloys is longtime
known but still of basic interest. The present investigation was
performed with a rectangular extruded bar with an initial texture
composed of <0001> fibre //ND, <10.10>fibre // ED, {0001}<10-10>
ideal component and {11-20}<10-10>. Compression tests were made
with compression axis //ND, //TD and // ED of the extruded bar,
while tension was done with samples of ED, TD and 45° oriented
samples. In- situ experiments were carried out with high energy X-
rays for fast measurements to follow texture evolution as well as
lattice strain and microstrain evolution. The beamline HEMS@Petra
III was used with about 87keV. In all cases one can see the strong
influence of the initial texture on the texture evolution and,
particularly for tension, the different behavior of initial texture
components on reactivity during plastic deformation is more
evident. The compression texture of Mg shows an orientation of the
<0002> // to the compression axis with different scatter and
different texture sharpness. MgAZ80 shows only a moderate texture
sharpness compared to other alloys or commercially pure Mg.
Tensile load leads to a double pole in the basal pole figure with tilt of
15° in ±TD. Texture sharpness decreases in all cases of tension.
During in situ loading the typical stress strain curve was documented
and, in parallel, up to 250 diffraction patterns were collected. Due to
the high synchrotron energy, the wavelength is very short and
consequently complete Debye-Scherrer rings were obtained. Lattice
strain behavior will be correlated on one hand related to the texture
evolution and on the other hand as diffraction pattern parallel and
perpendicular to the loading direction.
The synchrotron experiments were accompanied by texture
simulations, bulk texture analysis using neutron diffraction and EBSD
investigations. Besides intensity pole figures (crystallographic
texture) we also present line broadening pole figures (microstrain).
[1] S.-B. Yi, C.H.J. Davis, H.-G. Brokmeier, R.E. Bolmaro, K.U. Kainer & J. Homeyer (2006) Acta Mat. 54, 549-562.
[2] H.-G. Brokmeier, M. Jiang, E. Maawad, B. Schwebke & T. Lippmann (2011) Mat. Sci. Forum 690,198.
[3] Z. Zhong, H.-G. Brokmeier, E. Maawad & N. Schell, (2015) Mat. Sci. Engineering A639, 519.
Failure behaviors of E-form and AZ31 Mg alloys: Crack initiation and propagation during mini-V-bending tests Jaiveer Singh1, Min-Seong Kim1, ByungKyu Kim2, Dong-Ik Kim2, Shi-Hoon Choi1 1Department of Printed Electronics Engineering, Sunchon National University, Suncheon, Jeonnam, 540-950, Republic of Korea. 2High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seongbuk-gu, Seoul, 136-791, Republic of Korea
Deformation and failure behaviors of E-form fine grain (EFG), E-form
coarse grain (ECG) and AZ31 magnesium (Mg) alloys sheets were
investigated using a mini-V-bending test. These rolled sheets of Mg
alloys with different initial textures and grain sizes were studied to
reveal the role of strain heterogeneities through thickness direction
and crack initiation on the bended surface at different punch
strokes. The evolution of the microstructure and microtexture of the
deformed E-form and AZ31 Mg alloys were analyzed via an electron
back-scattered diffraction (EBSD) technique. Finite element analysis
(FEA) was used to capture the heterogeneous distribution of
longitudinal-strain components through the thickness direction
under mini-V-bending at different punch strokes. The relationships
between punch stroke, bending radius and longitudinal-strain at the
tension and compression zones were established. EBSD analysis
revealed that compression and double twins along with shear
localization by dislocation slip were the main deformation
mechanisms in the tension zone while tensile twins were a main
deformation mechanism in the compression zone in E-form and
AZ31 Mg alloys during mini-V-bending. The effects that deformation
twinning had on the crack initiation and propagation sites in E-form
and AZ31 Mg alloys were also investigated. The networks of
compression {1011} and double {1011} − {1012} twins in the
tension zone were closely related to the crack initiation and
propagation during mini-V-bending at room temperature. A resolved
shear stress (RSS) criterion which is based on the Schmid tensor, was
also used to analyze the activation of twin variants in rolled E-form
and AZ31 Mg alloys. The E-form Mg alloys with a weaker texture
show better formability or deformation behaviors during mini-V-
bending compared to AZ31 alloy with a stronger texture.
ABSTRACTS MONDAY AM - DEFORMATION 19
Towards high ductility in magnesium alloys - the role of grain boundary misorientation and deformation compatibility Jie Suna, b, Li Jina, Jie Donga, Fenghua Wanga, Shuai Donga, Wenjiang Dinga,c, Alan A. Luob, d aNational Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University, Shanghai 200240, PR China. bDepartment of Materials Science and Engineering, The Ohio State University, Columbus, OH 43210, USA cState Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, PR China. dDepartment of Integrated Systems Engineering, The Ohio State University, Columbus, OH 43210, USA
This paper investigates the role of grain boundary misorientation
and grain-level deformation compatibility in the plasticity of
magnesium alloys, using in-situ tension in scanning electron
microscopy (SEM) combined with electron backscattered diffraction
(EBSD) and digital image correlation (DIC) techniques. The majority
of activated dislocation slip traces were found to form in pairs across
grain boundary, and basal-to-basal (B-B) slip pair was the dominate
type. Grain boundaries with misorientation about 10-30° around
[0001] axis were found to promote the activation of B-B slip pairs. In
addition, a geometric parameter, m’, can be used to quantify the
possibility for the activation of B-B slip pairs. More activation of
basal B-B slip pairs was found around the boundaries with higher m’
values. Furthermore, a material with misorientation distribution
related to a higher average m’ value would achieve more elongation.
Therefore, optimizing misorientation distribution could be a new
solution to improving the ductility of Mg alloys in the future.
Texture and microstructure evolution of magnesium sheets during bending J. H. Cho1, Y. S. Lee1 and G. Lee1 1Korea Institute of Materials Science, Changwon, South Korea
AZ31 magnesium sheets fabricated by twin-roll casting were bent
using controlled bending machine at various temperatures. Initial
texture and microstructure of AZ31 sheets reveals a strong basal
texture and equiaxed grains. During bending, inner surface (concave
side) experienced compressive stress and negative strains occurred.
While, outer surface (convex side) went through tensile stress and
positive strains occurred. Different deformation mode on each side
caused by bending resulted in dynamic texture evolution. Twinning
in addition to slip played an important role. Annealing also affected
grain structure and mechanical properties changed.
Variant selection of {10-12}-{10-12} double twins during the tensile deformation of Mg alloys R.L. Xin1, C.F. Guo1, J.J. Jonas2, G. Chen1, Q. Liu1 1College of Materials Science and Engineering, Chongqing University, Chongqin, China. 2Department of Materials Engineering, McGill University, Montreal, Canada.
Secondary {10-12} twins can form within primary {10-12} twins in
Mg alloys, forming {10-12}-{10-12} type (extension-extension) twins.
Such secondary {10-12} twinning is sometimes associated with very
small or even negative values of the Schmid factor (SF). The
formation of such negative SF twins must therefore be attributed to
local effects. The variant selection of {10-12}-{10-12} secondary
twins is analyzed by employing a geometric compatibility factor
linking the twinning and slip accommodation modes. To generate
such unusual twins, specially designed samples were machined out
of a thick, hot-rolled coarse-grained AZ31 alloy plate. These samples
were subsequently deformed in tension along the normal direction
of the plate. Under such conditions, all six primary {10-12} variants
were activated, and selected secondary variants were produced at
the intersections of the primary variants. The crystallographic
aspects of the secondary variants are analyzed and linked to the
crystallographic features of the intersecting primary twins. Although
ten different orientation relationships have the potential to form,
only two were observed. Here most of the secondary twins had
misorientations of 49.7°<-909-4> with respect to their hosts. The
observed variant selection is explained in terms of strain
accommodation by basal glide in the host primary twins.
ABSTRACTS MONDAY AM – RUDY WENK 20
Symposium W: A Celebration of the Contributions of Rudy Wenk Symposium Chairs:
Dr. Lowell Miyagi, Geology & Geophysics, University of Utah
Dr. Pamela C. Burnley, Department of Geoscience, University of Nevada, Las Vegas
Dr. Sven Vogel, Los Alamos National Laboratory
In-Situ Studies of Microstructures under Deep Earth Conditions: from Texture Analysis to Multigrain Crystallography S. Merkel Université de Lille, 59000 Lille, France
In 2000, Rudy Wenk published the first paper describing a full in-situ
texture analysis from diamond anvil cell measurements in which he
analyzed the compression texture in hcp-Fe at 211 GPa [1]. The
experimental method was later significantly improved and applied
to other higher pressure devices such as the deformation-DIA [2].
Over the years, the combination of lattice strain and texture analysis
have allowed for a new understanding of microstructures in
minerals and metals under the conditions of deep planetary interiors
[3,4]. This field of research is now being extended to more advanced
methods allowing the tracking of microstructures at the individual
grain level [5]. This presentation will review the advances in the
analysis of textures and microstructures under deep planetary
conditions that, thanks to the contribution of Rudy Wenk and the
people who gravitated around him, became a strong and dynamic
field in texture analysis. I will start with an overview of the methods,
developments, and results that were allowed thanks to the
contribution of Rudy Wenk and will finish my presentation with
results of more recent experiments in which we follow
transformation microstructures grain by grain and in-situ in deep
planetary materials.
[1] H.R. Wenk, S. Matthies, R.J. Hemley, H.K. Mao, J. Shu (2000) Nature 405 1044
[2] H.R. Wenk, G. Ischia, N. Nishiyama, Y. Wang, T. Uchida (2005) Phys Earth Planet Inter 152, 191
[3] S. Merkel, A. Kubo, L. Miyagi, S. Speziale, T. S. Duffy, H.K. Mao, H.R. Wenk (2006) Science 311, 644
[4] L. Miyagi, W. Kanitpanyacharoen, P. Kaercher, K. K. M. Lee, H.R. Wenk (2010) Science 329, 1639
[5] A.D. Rosa, N. Hilairet, S. Ghosh, J.-P. Perrillat, G. Garbarino, S. Merkel (2016) J Geophys Res 121, 7161
Deformation and texture development in lower mantle mineral phases: What does seismic anisotropy in the deep Earth tell us about deformation? Lowell Miyagi Department of Geology and Geophysics, University of Utah, Salt Lake City, Utah 84112-0111, USA
In many regions of the Earth’s deep interior, seismologists observe
anisotropic propagation of seismic waves. This is believed to be due
to deformation induced texturing of rocks in the Earth’s interior as a
result of solid-state mantle convection. If deformation behavior and
its relationship to texture and anisotropy development are well
understood, observations of seismic anisotropy can be used to infer
dynamic processes occurring in the deep Earth. However, deformation studies on lower mantle mineral phases
present unique challenges. Recreating relevant pressures and
temperatures in the laboratory is challenging, and the mineral
phases of interest are unquenchable or highly unstable at ambient
conditions, necessitating in-situ analysis.
One of Rudy Wenk’s major contributions is in the field of high
pressure and high temperature texture studies. By combining
unconventional deformation devices such as the diamond anvil cell
with radial synchrotron x-ray diffraction, Rudy developed a
technique to allow in-situ measurement of lattice strains and texture
development as samples undergo deformation at high pressures and
temperatures. Texture measurements combined with polycrystal
plasticity modeling can be used to infer deformation mechanisms
active during an experiment. Once deformation mechanisms are
established, results can be extrapolated to more complex
deformation scenarios such as slab subduction and mantle
convection. This presentation will discuss work on lower mantle
mineral phases that I began as a Ph.D. student with Rudy in 2004
and that continues to the present.
Deformation texture evolution of ω-Zr at high pressure Arul Kumar Mariyappan1, N. Hilairet2, Y. Wang3, R.J. McCabe1, I. J. Beyerlein4, C. N. Tomé1 1Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA. 2CNRS-UMET, Université Lille 1, 59655 Villeneuve d'Ascq, France. 3Center for Advanced Radiation Sources, Argonne National Laboratory, Argonne, IL, 60439, USA. 4Mechanical Engineering and Materials Departments, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
Transition metal zirconium has stable hexagonal close packed (α)
structure at ambient conditions and it transforms to simple
hexagonal (ω) structure under high pressure and/or high rate
deformations. Unlike the ground state α-Zr, the plastic slip modes of
ω-Zr or composite α-Zr containing retained ω-phase are not yet
known. In this work, for the very first time, we have studied the
plastic deformation behavior of ω-Zr through quasi-static
deformation texture evolution. Controlled high-pressure
experiments to transform α-Zr to complete ω-Zr followed by quasi-
static compression test of ω-Zr are performed. Initial and
deformation texture at different strain levels of ω-Zr is measured
using in-situ X-ray diffraction. Visco-Plastic Self-Consistent (VPSC)
crystal plasticity modeling tool is employed to predict the
deformation behavior and texture evolution of ω-Zr. Comparing the
predicted deformation texture with the measurements, we develop
an understanding of crystallographic slip activity in ω-Zr. In this
work, we also studied the influence of initial α-microstructure on the
transformation texture and also on the deformation texture
evolution of ω-Zr.
ABSTRACTS MONDAY AM – RUDY WENK 21
Preferred orientation in a linear viscous flow: High T torsion experiments on Diopside-Anorthite aggregates J. Gómez Barreiro1, H.-R. Wenk2, E. Ribacky3, G. Dresen3, Y. Ren4, J.M. Benítez Pérez1
1University of Salamanca, Salamanca, Spain. 2University of California, Berkeley, USA. 3GeoForschungsZentrum, Postdam, Germany. 4Argonne National Laboratory, Argonne, USA.
Understanding deep Earth rheology mainly relies on indirect
observations. The knowledge we have about the behaviour of rocks
and minerals at different conditions and its correlation with physical
properties (e.g. elasticity), determines how we interpret and model
geophysical data in geodynamic terms (e.g. seismic signal). However,
fundamental questions like the correlation of deformation
mechanisms and mechanical response of polyphasic aggregates at
the Earth interior conditions are not well understood. Experimental
evidences up to date establish the presence or absence of
crystallographic preferred orientation (CPO) or texture as
unequivocal proof of dislocation / diffusional creep dominance, as
well as the mechanical behaviour. Here we show texture in torsion-
deformed polymineral aggregate, composed of anorthite and
diopside (50%). Texture symmetry is coherent with the simple
shearing and the mechanical behaviour is linear-viscous
(Newtonian). Visco-plastic self-consistent numerical simulation of
texture and microstructural observation suggest that a cooperation
of dislocation activity and grain-boundary sliding/diffusion better
explain the results. All these features are opposed to the common
belief that restricts to non-Newtonian rheologies the development
of CPO. This is significant since seismic anisotropy in Earth has been
correlated with the presence of texture. Our results demonstrate
that no rheological behaviour can be derived only from seismic
anisotropy, geophysical observation or texture presence in
polyphasic aggregates.
ABSTRACTS MONDAY AM - RECRYSTALLIXATION 22
Symposium R: Crystallization, recrystallization and growth textures Symposium Chairs:
Dr. Rodney McCabe, Los Alamos National Laboratory
Asher Leff, Department of Materials Science and Engineering, Drexel University
Texture and microstructure of advanced high strength steel after fast heating and short annealing R.H. Petrov1,2 F.M. Castro Cerda1,3, Ilchat Sabirov4, Athina Puype1, Dorien De Knijf5 and L.A.I. Kestens1,2 1Ghent University, Ghent, Belgium, 2Delft University of Technology, Delft, The Netherlands, 3Universidad de Santiago de Chile, Santiago, Chile, 4IMDEA-Materials Institute-, Madrid, Spain, 5OCAS-nv, Belgium
The microstructure and texture changes in advanced high strength
steels after conventional (10°C/s), and ultrafast (400-1000°C/s)
heating and very short soaking times of ± 0.5s were studied. The
steels with initial microstructure of ferrite and perlite or ferrite and
tempered martensite were 50 or 75% cold rolled before the
annealing. All heat treatments were carried out on a Gleeble
thermo-mechanical simulator and the maximum annealing
temperature was in the two-phase austenite-ferrite temperature
range. The annealing was followed by quenching at an average
quench rate of ~-160 °C/s. This type of treatment is also known as
“flash” annealing. Microstructures and textures of the samples were
studied by optical microscopy, scanning electron microscopy and
electron backscatter diffraction.
The results of the texture analyses of the individual structural
constituents show that heating rates as high as 400°C/s, 800°C/s and
1000°C/s and very short soaking times (0.2-0.5s) can shift the start
of the recrystallization of ferrite to high temperatures. Additionally,
it causes the formation of the intercritical austenite either from
recrystallized or non-recrystallized (or recovered) ferrite. As a
consequence, the microstructure refines and characterizes with very
fine partially recrystallized or recovered ferrite grains and finely
distributed martensitic islands, bainite, Widmanstätten ferrite,
retained austenite and undissolved cementite. The martensite
texture formed after fast heating, short annealing and quenching is
very similar to the initial texture after cold rolling (texture memory
effect) but with lower intensity. After increasing the soaking time
from 0.5 s to 30 s or 60 s, the recrystallization and grain growth take
place and the effect of fast heating vanishes.
The results of this work could be of importance for development of
industrial heat treatment processing routes with application of fast
and ultra-fast heating combined with very short soaking.
Texture evolution during partial recrystallization annealing in high strength automotive steels S. Janakiram1, Jai Prakash Gautam1 and L.A.I. Kestens2
1School of Engineering Sciences and Technology, University of Hyderabad, Gachibowli, Hyderabad, Telangana 500046, India. 2Department of materials science and engineering, Ghent University, Ghent, Belgium
Currently automotive industry is aiming to reduce the weight of the
car body while maintaining its strength and formability. The
crystallographic texture is one of the main physical parameters
responsible for controlling the formability of steel. The texture of
steel is a function of materials and process parameters: chemical
composition, hot band microstructure and texture, cold rolled
reduction, recrystallization process. With the increasing use of high
strength steels is essential to study more comprehensively the
concurrent ferrite recrystallization and second phase effect during
annealing of two phase steels or, more generally, high strength
steels. It reveals some clear differences in recrystallization behaviour
with the well-studied single phase ferrite steels: presence of new
nucleation sites in fragmented regions, grain growth limited by
pearlite band. In general, the behaviour of second phases as
pearlite, bainite during recrystallization annealing is not well
established.
The present study is mainly focused on effect of hot deformation
temperature (Tnr) on the recrystallization texture after 80% cold
rolling. Special attention is paid to understand the nucleation and
growth mechanism with the effect of second phase as pearlite and
bainite constituent. Results are analysed with the help of optical
microscope, Vickers hardness and texture through EBSD.
Results clearly show the effect of hot deformation (Tnr) on
microstructure and recrystallization kinetics. Microstructure
consisted of coarse non banded and fine banded morphology of
ferrite, pearlite and bainite. Faster Recrystallization kinetics are
observed for Below Tnr compared to above Tnr. Heterogeneous
nucleation of grains took place with orientation nucleation
mechanism. Results suggest the reappearance of hot band texture at
the onset of recrystallization.
The effect of the pre-heating temperature and heating rate on the textures of cold-rolled low-carbon steel F.M. Castro Cerda1,2, L.A.I. Kestens1,3 and R.H. Petrov1,3 1Ghent University, Ghent, Belgium, 2Universidad de Santiago de Chile, Santiago, Chile, 3Delft University of Technology, Delft, The Netherlands .
The effect of heating rate on the microstructure and texture of ultra-
low and low carbon steel has been recently studied. The heat
treatments carried out in these studies are of the “peak-annealing
and quenching” type, in which the test specimens are heated
continuously, held for very short times (less than 0.5 s) at the peak
temperature and quenched. However, the industrial application of
the peak-annealing (also called flash) process on cold-rolled steel
plate might require a slight modification. In the present study, the
effect of a pre-heating stage on the textures of 50% and 75% cold-
rolled low carbon steel is investigated. The pre-heating stage
consists of heating the test specimens at a conventional rate (10
°C/s) to a pre-heating temperature and holding isothermally for 30 s,
followed by the 'peak annealing' type of thermal cycle. Two pre-
heating temperatures were selected, namely 300 and 400°C. After
the pre-heating stage, the peak-annealing experiments were carried
out under two heating rates (10 and 400 °C/s) with a holding time of
1.5 s, followed by quenching (~-160 °C/s).
ABSTRACTS MONDAY AM - RECRYSTALLIZATION 23
The pre-heating temperatures show negligible effects on the cold-
rolled microstructure and ferrite textures. The recrystallization
textures are rather insensitive to the pre-heating stage. The increase
of the heating rate after the pre-heating stage shows strengthening
in the intensity of grains oriented close to <111>//ND, as well as in
some <110>//RD texture components. The texture memory effect
plays a role in the formation of the martensite texture after
quenching, whereby the texture is also affected by the heating rate
on the nucleation of austenite. The results indicate that a pre-
heating stage before the application of peak-annealing cycles does
not modify the microstructure and the textures in a significant way.
The results of the present study are expected to be of significance
for the industrial application of ultrafast heating rates to cold-rolled
low carbon steel plate.
Effects of initial microstructure/texture and cold-rolling reduction on texture and r-value in ferritic stainless steel sheets. Kou NISHIMURA1, Jun-ichi HAMADA2, Yoshiharu INOUE1, and Kenichi MURAKAMI1 1Nippon Steel and Sumitomo Metal Corporation, Kitakyushu City, Japan. 2Nippon Steel and Sumikin Stainless Steel Corporation, Hikari City, Japan
The Lankford value (r-value), which is a basic index for the
formability of ferritic stainless steel sheets, is closely related to their
recrystallization textures. In this study, the effects of initial
microstructure/texture and cold-rolling reduction on the r-value and
recrystallization behavior of ferritic stainless steel were investigated
to clarify {111} nucleation behavior.
Three Type 409L ferritic stainless steels were used. They had
different initial microstructure and area fraction of {111} grains.
After cold-rolling and annealing them, we investigated the
relationship between formability and recrystallization texture by the
r-value test and X-ray measurement. Furthermore, the Vickers
hardness test and EBSD measurement were conducted to clarify
recrystallization behavior.
It became clear that the effects of cold-rolling reduction on
recrystallization texture depended on initial microstructure and
texture because the main nucleation site changes from the vicinity
of grain boundaries to deformed {111} grains according to cold-
rolling reduction.
Texture characterization of AISI 316 L steel processed by selective laser melting F.C. Pinto1, M. Avalos2, R.E. Bolmaro2 and H.R.Z. Sandim1 1Lorena School of Engineering, University of Sao Paulo, Lorena, Brazil. 2Instituto de Física de Rosario, Rosario, Argentina.
Additive manufacturing is an emerging technology able to produce
unique microstructures and textures in traditional materials,
depending on the chosen scanning strategy. We report the main
results of the texture characterization of AISI 316L austenitic
stainless steel processed by selective laser melting (SLM) of metal
powders. To date, the literature presents very little information on
the texture evolution of this steel, or even other alloys processed by
SLM, upon post-processing heat treatments. The material was
characterized in the "as-processed" condition and after isothermal
annealing within a wide range of temperatures (950-1150oC), with
emphasis on the evolution of the crystallographic texture during
coarsening of the microstructure. The texture of the as-processed
steel is rather weak, composed mainly of {011} planes contained on
the deposition plane and perpendicular to the growth direction,
with tetragonal symmetry promoted by the alternative deposition of
[011]<001> layers, where the <001> points alternatively along the
successive laser scan directions. Further isothermal annealing
changes both texture and mesotexture, in particular the increase of
-3 special twin boundaries.
ABSTRACTS MONDAY AM - ENGINEERING 24
Symposium A: Texture and Anisotropy in Advanced Engineering Processes and Materials Session: Advanced Materials
Symposium Chairs:
Professor Tracy Nelson, Department of Mechanical Engineering, Brigham Young University
Dr. Ashley Spear, Department of Mechanical Engineering, University of Utah
Microstructure effects of mechanical alloying on SPS sintered Fe-Al-Si powders J. Kopeček1, J. Remiášová1, L. Klimša1, F. Průša2, K. Nová2 and P. Novák2 1Institute of Physics of the AS CR, Prague, Czech Republic. 2University of Chemistry and Technology Prague, Prague, Czech Republic.
Iron aluminides/silicides are cheap materials with interesting
corrosion and mechanical properties, mainly at high temperature
range. Nevertheless, their preparation is not easy task and powder
methods are frequently used to prepare volume material. We
exploit previous knowledge of our team both in reactive sintering
and Fe-Al-Si system to investigate the microstructure, phase
composition, mechanical and corrosion properties of cast and
mechanical alloyed sintered materials [1-4].
The phases’ formation mechanism in Fe-Al-Si system during
mechanical alloying is described in the Fe-Al-Si alloy powder
prepared by mechanical alloying. The powders of the Fe-Al-Si alloy
prepared under the optimized conditions are consolidated by spark
plasma sintering (SPS) in the next step. The mechanism and kinetics
of the formation of intermetallics will be described by the analysis of
the morphology, microstructure and phase composition after
various process durations and milling conditions. It is very important
to characterize the processes during MA at the level of individual
powder particles, therefore special techniques including FIB-SEM,
EBSD, TEM and nanoindentation will be utilized. We evaluate the
influence of the production technology on the microstructure and
related mechanical and corrosion properties.
Here the results obtained on the Fe – 20 wt. % Al – 20 wt. % Si will
be presented with respect to mechanical alloying and spark plasma
sintering process optimization based on SEM and EBSD
investigations.
[1 P. Novák et al. (2011) Intermetallics 19 1306. [2] P. Novák et al. (2011) Powder Metallurgy 54 167. [3] P. Novák et al. (2010) J. Alloys Comp. 493 81. [4] P. Novák et al. (2010) J. Alloys Comp. 497 90.
Oxidation Kinetics of Steel: The Defining Role of Substrate Micro-texture H. K. Mehtani*, M. I. Khan, A. Durgaprasad, S. Parida, M.J.N.V. Prasad and I. Samajdar Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Powai (400076), India
Two different steel grades, IF (interstitial free) and fully pearlitic
(near eutectoid), were used. Substrates with different micro-
textures showed remarkable difference in oxidation kinetics. In fully
ferritic IF steel highest oxidation rate was in ND//<111> grains; while
in eutectoid steel the rate of oxidation scaled with ferrite-cementite
interface area and the exact nature of the phase boundary. In both
grades, the oxidation rate did relate to the chemical nature and the
physical morphology of the oxide film. Hetero-epitaxial growth
stresses of the oxide film were measured by using Raman
Spectroscopy and multiple {hkl} grazing incident X-ray diffraction.
Such stresses were shown to have a clear relationship with the
substrate micro-texture, and determined the oxidation kinetics of
the respective grades/microstructure.
Effect of temperature and crystallographic orientation on superelastic strain of FeNiCoAlTaB single crystals R. Chulist1, T. Tokarski2, G. Cios2, W. Maziarz1, N. Schell3 Y.I. Chumlyakov4 1Institute of Metallurgy and Materials Science, Polish Academy of Sciences, 25 Reymonta Street, Kraków, 30-059, Poland. 2AGH University of Science and Technology, Academic Centre for Materials and nanotechnology, Mickiewicza 30, 30-059 Krakow, Poland. 3Institute of Materials Research, Helmholtz-Zentrum Geesthacht, Max-Planck-Strasse 1, D-21502 Geesthacht, Germany. 4 Tomsk State University, Siberian Physical Technical Institute, Tomsk 634050, Russia
Fe-based alloys (Fe-28Ni-17Co-11.5Al-0.5Ta-0.5B abbreviated
NCATB) belong to a new family of shape memory alloys showing a
large superelastic strain at room temperature [1,2]. However,
significant strain differences between single and polycrystals are
observed. Therefore, to provide an insight into the mechanism of
superelasticity observed in NCATB alloys single crystals with <100>,
<110>, <111> and <112> orientations were compressed at different
temperatures (273, 123, and 77 K). Elastic, plastic or elasto-plastic
response are observed depending on the orientation and
deformation temperature. The global and local orientation
measurements are determined by diffraction of high-energy
synchrotron radiation and electron backscatter diffraction,
respectively. The results are discussed with respect to
crystallographic orientation, deformation mode, precipitations and
phase transformations.
[1] Y. Tanaka, Y. Himuro, R. Kainuma, Y. Sutou, T. Omori, and K. Ishida, Science 327, (2010) 1488
[2] T. Omori, K. Ando, M. Okano, X. Xu, Y. Tanaka I. Ohnuma, R. Kainuma, and K. Ishida, Science, 333 (2011) 68
Crystal Plasticity Finite Element Modeling of Polycrystal NiTi Shape Memory Alloy (SMA) S. Dhala, S. Mishra, A. Alankar
Department of Mechanical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, Maharashtra, 400076, India
NiTi SMA are a special class of metallic alloys that remember their
original undeformed shape. These metals are capable of recovering
large strains (order 6-7%) by heating (shape memory effect) or at
higher ambient temperatures, simply by unloading
(pseudoelasticity). In this paper, we present a crystal plasticity finite
element model for polycrystal pseudoelastic NiTi SMA considering
ABSTRACTS MONDAY AM - ENGINEERING 25
slip, phase transformation and deformation twining modes. The
model is used to predict macroscopic mechanical response under
uniaxial deformation. Finite element analyses are carried out for a
representative volume element consisting of randomly oriented
grains and subjected to periodic boundary conditions. Material
parameters for slip, transformation and twin modes are determined
by fitting the stress-strain curves with single crystal experimental
results. Predicted deformation behavior of polycrystalline NiTi SMA
is compared against the experimental data. Localized stress
concentrations and martensite transformation are observed due to
heterogeneous deformation driven by crystallographic orientations.
There is a good agreement between simulation results and
experimental data, which validates the proposed crystal plasticity
model. The model can be further extended to investigate the effect
of temperature, strain and texture on mechanical behavior of
pseudoelastic NiTi SMA.
Deformation Analysis of Alumina Compressed at High Pressure Using Electron Channeling Contrast Imaging (ECCI) and Electron Backscatter Diffraction (EBSD) S. Kaboli, and P.C. Burnley University of Nevada Las Vegas, Las Vegas, USA.
Polycrystalline α-alumina is commonly used as material for
deformation pistons in sample assemblies for the D-DIA apparatus
used in in-situ X-ray synchrotron deformation experiments. Despite
the higher strength of alumina relative to geological materials under
study, the alumina pistons occasionally fail during D-DIA
experiments, meaning that the pistons bulge out or shorten during
compression. The piston failure results in underestimated stress
measurements for the sample. These underestimated stress values
result in internally inconsistent and irreproducible datasets from D-
DIA experiments which have been commonly reported by previous
workers. Thus, deformation analysis of alumina compressed at high
pressure in the D-DIA apparatus is all the more urgent. The
objectives of this study are two-fold. First, we use electron
channeling contrast imaging (ECCI) in field emission scanning
electron microscope (FE-SEM) to image dislocations under known
diffraction conditions and identify activated slip systems in grains
that are not twinned. Second, we use electron backscatter
diffraction (EBSD) to identify twin laws operating in alumina. In
comparison to conventional deformation analysis using transmission
electron microscopy (TEM) on thin foils, the main advantages of SEM
include fast and non-destructive bulk specimen preparation and
statistically reliable results from a large field of view in a bulk
sample.
We establish a successful procedure for specimen preparation and
microscope operation to perform dislocation imaging with ECCI in
FE-SEM. We perform EBSD analysis to identify the angle–axis pair of
misorientation between two adjacent crystals domains to identify
the twin laws. This analysis involves a comparison between
experimental and theoretical pole figures for rhombohedral
twinning and assessment of the symmetry and rotational
relationship between twin and parent grains in order to confirm the
type of twinning. Additionally, we use EBSD to provide a quick
automated quantitative analysis of twinning laws distributed across
the polycrystalline aggregate.
Our preliminary ECCI images in FE-SEM confirmed the presence of
edge-on basal dislocations obtained for the first time from deformed
alumina at high pressure. We demonstrate the invisibility criterion
through variations in channeling contrast with sample tilt series
similar to dislocation analysis commonly performed in TEM. For
twin law identification, we analyzed our EBSD data by comparing six
experimental pole figures for the basal {0001}, prismatic {10-10}, {1-
210}, pyramidal {10-11}, and rhombohedral {01-12} families of
planes and the <02-21> family of directions with corresponding
theoretical pole figures for rhombohedral twinning. We also verified
rhombohedral twin symmetry and the 85° rotational relationship
between twin and parent grains. We also noted the presence of
surface porosity which implies that the orientation of the twins with
respect to the overall compression direction is not informative since
the collapse of the porosity would create large variations in the local
stress field across the sample.
ABSTRACTS MONDAY AM -CHARACTERIZATION 26
Symposium C: Texture and Microstructure Characterization Symposium Chairs:
Dr. Irene Beyerlein, Department of Mechanical Engineering, University of California, Santa Barbara
Dr. Mukul Kumar, Lawrence Livermore National Laboratory
Dictionary Indexing Approach for Electron Diffraction Modalities F. Ram, S. Singh and M. De Graef Carnegie Mellon University, Pittsburgh, USA.
All single crystal diffraction modalities, whether they use electrons
(EBSD, PED, ECP, CBED, …) or X-rays (transmission and reflection
Laue) have in common the need for an algorithm to extract the
lattice orientation from the positions of the features (spots, bands,
lines, …) in the diffraction pattern. We will refer to the orientation
extraction process as “indexing the pattern.” Finding features in a
diffraction pattern requires an image processing step (the Hough
transform in the case of EBSD) followed by identification of the
locations of the main features and conversion of those locations into
an orientation. In the dictionary indexing approach, one relies on a
forward model to predict diffraction patterns for a range of
orientations uniformly sampling orientation space, SO(3), and then
each of those pre-computed patterns is compared, using an image
similarity metric, to each of the experimental patterns; the
orientation corresponding to the best matching pattern is then
assigned as the solution.
In this contribution, we will briefly describe a physics-based forward
model for the generation of EBSD patterns, as well as a new
mathematical approach to obtaining a uniform sample of
orientations. The forward model consists of (1) a Monte Carlo
simulation to determine the depth-energy-direction histogram of
back-scattered electrons for a given sample tilt and incident electron
energy; (2) a dynamical electron scattering simulation covering the
range of possible electron directions; and (3) a geometrical model
for the sample-detector geometry. We will provide examples of
forward calculations for a number of different crystal structures.
This process is then repeated for each crystal orientation taken from
a uniform set of orientations based on the cubochoric sampling of
SO(3). The resulting pattern dictionary can then be used to find the
best matching pattern for each experimental pattern; the dot
product between normalized pattern vectors provides a useful and
efficient similarity metric.
While this indexing process is slow compared to the Hough-based
indexing available in commercial EBSD packages, we will show that
this approach has a number of advantages: (1) robustness against
noise (the approach does not look for pattern features but compares
entire patterns); (2) ability to refine the orientation sampling to
improve the pattern match; (3) ability to index overlapping EBSD
patterns, which occur near grain boundaries; (4) ability to obtain
average orientations, since the approach stores not only the best
matching pattern orientation, but several near matches as well; (5) a
precise definition of the confidence index for the pattern match.
Finally, since there is always a best match, there are no un-indexed
points that require manual or semi-automated correction after the
indexing process has concluded. Needless to say, the approach
requires that every EBSD pattern be stored on disk, which results in
very large data sets when fine scale sampling is used or when full-
scale patterns are employed.
We will provide examples of dictionary indexing for a number of
material systems, including Nickel; a geological sample consisting of
garnet, clinopyroxene and amorphous melt; shot-peened Aluminum;
and a high-cycle fatigued ultra-fine grained steel.
Improved spatial and angular resolution of EBSD-based texture measurement of deformed and fine-grained materials F. Ram1, S. Singh1, A. Gholinia2, T.L. Burnett2, B. Winiarski2 and M. DeGraef1 1Carnegie Mellon University, Pittsburgh, USA . 2University of Manchester, Manchester, UK.
The Electron Backscatter Diffraction technique (EBSD) in a Scanning
Electron Microscope is a standard choice for measuring the micro-
texture of a bulk material. The EBSD analysis based on the Hough
transform works very efficiently in most cases; and when lattice
rotation gradients are small or a high accuracy is required, the cross-
correlation-based analysis is the substitute. When a highly deformed
or an ultra-fine grained material is being characterized, however, the
performance of these two methods worsens. This is due to pattern
degradation as a result of the largest dimension of the beam-
specimen interaction volume exceeding the spatial variation length
of the lattice rotations.
To capture this spatial variation, the electron beam-specimen
interaction volume must be reduced in volume, which requires
reducing the electron beam energy. At 5 keV, the largest dimension
of the beam-specimen interaction volume in Al is about 80 nm; it is
260 nm at 20 keV. Adopting this strategy partially alleviates the
spatial resolution issue, but does not improve the performance of
the two above-mentioned methods because at a lower accelerating
voltage, the EBSD pattern quality is severely degraded. The number
of points whose orientations can be determined by the Hough-
transform analysis decreases from 95% at 20kV to 5% at 5 kV in a
shot-peened Al sample.
In this contribution, we will review the dictionary-based indexing
approach and show how it robustly deals with low-quality patterns.
The same shot-peened aluminum specimen measured at 5 keV was
analyzed by dictionary indexing, which successfully determined the
orientation of more than 85% of the measured points. At 10 keV,
even the smallest grains near the shot-peened surface could be
resolved and indexed successfully. Our analysis will show that we
have improved the effective spatial resolution of EBSD, so that
details of the deformed microstructure (multi-walled grain and sub-
grain boundaries) are revealed that could not be imaged and
quantified by EBSD before.
ABSTRACTS MONDAY AM -CHARACTERIZATION 27
Pole figure measurement methods for centerless X-ray diffractometers M. Benke1, M. Sepsi1 and V. Mertinger1 1University of Miskolc, Miskolc, Hungary.
The present paper introduces new texture measurement methods
developed for mobile/fixed centerless X-ray diffractometers. Using
these methods pole figures can be obtained with all the benefits of
centerless diffractometers: no need for sample cutting, flexibility in
case of large components with complex shapes, short measuring
time and portability. The paper describes the measurement
methods, includes the validations with conventional pole figure
measurements and provides instances of applications of the new
technique.
Quantification of local anisotropy and microstructure-property relationships using canonical correlation analysis Sudipto Mandal, Jacky Lao and Anthony D. Rollett Carnegie Mellon University, Pittsburgh, PA, USA.
Microstructure-property relationships in two-phase titanium alloys
have generally been evaluated qualitatively and are based on their
macroscopic behavior. However, structural and texture changes at
the microscopic scale can result in failure of a material much before
the macroscopic predictions. With the advent of powerful
computers and advanced data-driven techniques, the relationship
between local anisotropy, microstructural features and mechanical
properties can be efficiently quantified for a statistically large
volume of the material.
Canonical correlation analysis (CCA) has been used to understand
the effect of microtexture and microstructural features on the
deformation behavior and texture evolution during uniaxial
compression for Ti-6Al-4V. CCA is a multivariate approach that can
reveal the global sensitivities of individual variables in a model or a
phenomenon. CCA is preferred over other commonly used
sensitivity techniques because it provides a measure of both the
relative contribution of the variable and its interrelationships with
other variables. The microstructural and texture features analyzed in
this study include particle size, particle shape, grain orientation,
intragranular misorientation and grain boundary characteristics. An
elastoviscoplastic fast Fourier transform (FFT) simulation is used to
predict the local stress and strain rate behavior based on
representative 3D microstructures.
The predictions from CCA are compared with expected material
behavior based on physical explanations and experimental
observations. Quantifying local microstructure-property
relationships will aid in the identification of local sites more prone to
failure and the factors most likely to cause them. A better
understanding of these relationships will eventually allow greater
control over the performance of the material under extreme
conditions.
Geometric distortion corrections of EBSD Scans Francois Brisset1, Torkjell Breivik2, Bjørn Eske Sørensen2, Yingda Yu3, Jean-Claude Menard4 and Jarle Hjelen2,3
1ICMMO, CNRS / Unversité Paris-Saclay, Université Paris-Sud, Orsay, France. 2Department of Geoscience and Petroleum, NTNU, 7491 Trondheim, Norway. 3Department of Material Science and Engineering, NTNU, 7491 Trondheim, Norway. 4Ahead Microscopy, 1 allée des jonquilles, 78390 Bois d'Arcy, France
Some types of materials require EBSD mapping from large areas to
get representative results because grain sizes are in the order of
several mms and statistically significant crystal preferred
orientations require several hundred or thousands of individual
grain measurements. Typical examples are large silicon wafers,
geological thin sections, welding, etc. EBSD maps are acquired in x-
and y-directions with a certain overlap and in the end stitched
together to get a large area EBSD map. The larger the individual
square maps the faster the total acquisition will be as there will be
less stage moves and less recombination of areas. However, and
especially at low magnification, the scanned area will be distorted
due to the high EBSD tilt angle, typically 70˚ and this scanned area
will have a trapezoidal distortion if no shape correction is applied.
The distortion will increase with decreasing magnification. As a
consequence, stitching such areas with trapezoidal distortion leads
to mismatch between neighbor areas. To correct for this distortion a
theoretical or an experimental calibration method could be applied.
In the present case a calibration method has been developed to
correct for the distortion. A calibration specimen with square grids
has been used for the calibration procedure. The calibration
specimen was tilted and the SEM parameters (magnification, tilt
angle, high voltage, working distance) were set to the same
experimental values as for the real EBSD scan (done after the
calibration procedure). The EBSD detector should be in the in-
position during calibration. The calibration procedure is carried out
by marking 4 points on the distorted square grid. These 4 points
must be the corners on a square grid and the points should be close
to the 4 corners of the tilt corrected and dynamically corrected
electron image. The stage moves are applied either moving only x
and y in the case of a eucentric stage with a stage 70° tilted or
moving x, y and z if a pre-tilted specimen holder is used. In addition
of this procedure, automatically acquired, indexed and
reconstructed multi-area maps will be presented.
ABSTRACTS MONDAY PM - PLENARIES 28
MONDAY PM PLENARY SESSION
Deformation and grain growth of hexagonal metals: new insights with conventional and high resolution EBSD techniques V. Tong and T.B. Britton Department of Materials, Imperial College London, London, UK
Hexagonal metals are critical for many high-value high-risk applications. For instance, Zircaloy-4 is used in nuclear reactors in the form of thin-
walled fuel rod cladding tubes. In this application, maintaining a fine grain size is important to withstand the large thermal, mechanical and
irradiation stresses in operation. Under certain conditions, abnormally large grains, or blocky alpha (often >500μm in size) grow within the small
grained matrix (~15μm), which is undesirable for structural integrity of the fuel rod cladding.
Understanding the mechanism by which blocky alpha nucleates and grows is essential for both optimising manufacturing processes and
understanding in-service performance. In this work, EBSD and HR-EBSD analysis have been used to understand the nucleation of blocky alpha
grains in annealed three point bend specimens.
The final equilibrium size of the blocky grains is shown to be dependent only on the magnitude of the strain before annealing. However, the texture
of the annealed samples changes with both the tensile/compressive sense and magnitude of the strain. The texture differences in these four
regions (high and low strain regions on either side of the neutral axis) have been measured using EBSD. This likely due to a change in deformation
mode within the tensile and compressive faces of the bend specimen. Comparisons of heat treated samples and as-bent samples have been used
to understand the influence of deformation microstructure on abnormal grain growth.
A mechanism for blocky alpha formation can be proposed based on these results. It is likely that strain concentrations provide the driving force for
nucleation of blocky alpha structures. Nucleant grains are likely to be at local strain concentrations such as twin tips during deformation, so that
the nuclei have a different texture to the bulk plate. These nucleant grains consume other grains as they grow, producing a texture in the final
blocky alpha structure different to the parent texture.
Effects of texture on mesoscale characterization and modeling of heterogeneous deformation T.R. Bieler1, A. Chakraborty1, C. Zhang1, S. Balanchandran1 H. Phukan1, L. Wang2, Z. Zheng2, P. Kenesei3, J.-S. Park3, P. Eisenlohr1, M.A. Crimp1, C.J. Boehlert1 1Michigan State University, East Lansing, MI, USA, 2Shanghai Jiao Tong University, Shanghai, China, 3Advanced Photon Source, Argonne National Laboratory, Lemont, IL, USA.
Constitutive models for crystal plasticity simulations require an understanding of how the relative slip resistance varies among several slip systems,
and how these resistances evolve with strain. Because the details of deformation are complex in hexagonal systems, there is considerable
variability in experimental measurements of the critical resolved shear stress (CRSS) for different slip systems; ratios of prism/basal vary from 0.2-
0.8 in pure Ti. The variation is almost this large from assessments made on the same material with different methods. The CRSS value for <c+a> slip
cannot be measured directly, as basal or prism <a> slip is typically activated even if <c+a> slip has the maximum possible resolved shear stress.
Because many experiments show that <c+a> slip is active, knowing <c+a> CRSS values are important. Consequently, indirect methods such as
surface slip trace observations have been used to obtain relative slip resistances using a statistical approach recently developed by our group [1].
The statistics of these measurements depends on the texture and the deformation direction of the sample. To assess the ability to extract CRSS
values, a computational study that examines if the CRSS values used to computationally deform a polycrystal with different textures can be
extracted by assuming that slip systems showing large values of accumulated shear can be assessed to extract the CRSS input values.
Our group has also estimated CRSS using nanoindentation experiments in tandem with crystal plasticity models by matching surface topography
and load-displacement history using optimization strategies. Indentation experiments cause a state of stress that depends on the location under
the indent, which also evolves with depth of displacement. While indentation on a single grain makes the effect of texture irrelevant, at least two
measurements on significantly different grain orientations are required to sufficiently assess the operation of a sufficiently large variety of slip
systems.
Another approach uses in-situ far-field high-energy x-ray diffraction experiments to identify grains in which the lattice rotation is caused primarily
by a single slip system, from which the CRSS at yield of that particular slip system is extracted using from the measured strain (stress) tensor [2].
These experiments reveal a bimodal distribution correlated with surface vs. interior grains that indicates that hydrostatic stress states affect the
CRSS, so non-Schmid effects are probably significant.
As there are many variables involved in these techniques, the confidence in extracted CRSS values is an open question, leading uncertainty in
plasticity models developed subsequently. Thus, a systematic comparison of all three experimental methods has been carried out using two
ABSTRACTS MONDAY PM - PLENARIES 29
different lots of commercially-pure titanium, one with a weak texture and one with a strong texture. Supported partially by several past and
current NSF/DMR grants and by DOE/BES DE-FG02-10ER46637.
[1] H. Li et al., (2013), Acta Mater. 61, 7555-7567. [2] L. Wang et al. (2017), Acta Mater., in revision.
ABSTRACTS MONDAY PM - DEFORMATION 30
Symposium D: Deformation Textures Session: Titanium
Symposium Chairs:
Professor Chadwick Sinclair, Department of Materials Engineering, University of British Columbia
Professor Warren Poole, Department of Materials Engineering, University of British Columbia
Dr. Samantha Daly, Department of Mechanical Engineering, University of California, Santa Barbara
Understanding the texture and anomalous recrystallization behaviour of warmed rolled CP-Ti João Quinta da Fonseca The University of Manchester, Oxford Road, Manchester M12 9PL, UK
The texture of warm rolled commercial purity titanium (CP-Ti)
becomes stronger as the rolling temperature increases. Even more
unexpectedly, the recrystallization rate of the warm rolled material
increases with rolling temperature. The aim of work reported here
was to investigate the origin of these surprising observations and, in
particular, to determine to what extent this was a consequence of
the deactivation of twinning at higher temperatures.
CP-Ti was rolled at RT, 150C, 300C and 450C to different reductions
up to a maximum of 50%. The bulk texture of the rolled material was
measured using EBSD, which was also used to obtain higher
resolution maps for studying twinning. Crystal plasticity finite
element modelling (CPFEM) was used to simulate the texture
evolution during rolling. The material model used was calibrated on
a set of compression tests performed at the same temperatures and
at strain rates comparable to those of rolling. The relative changes
with temperature of the critical resolved shear stresses (CRSS) for
slip and twinning were inferred from the values available in the
literature and validated via comparison with the Lankford
coefficients measured after compression testing.
The CPFEM calibration revealed that as temperature increases, the
amount of twinning decreases as expected. Furthermore, although
all the CRSSs decrease with temperature, the CRSS ratio of
pyramidal <c+a> to prismatic slip increases with rolling temperature.
Both these effects are necessary to predict the increase in texture
strength observed. In addition, they offer an explanation for the
apparent anomalous increase in recrystallization rate. As the plastic
anisotropy increases, the deformation of the material becomes
more heterogeneous, as does the spatial distribution of stored
energy. Therefore, although more recovery occurs at the higher
rolling temperatures, the amount of plastic strain in the grains well
aligned for easy slip increases. This creates regions of high stored
energy and high local misorientation, which act as preferential sites
for recrystallization, causing an apparent higher rate of
recrystallization during annealing.
Microstructure and texture Evolution during Thermo-Mechanical Processing of Ti-6Al-4V Titanium Alloy Jyoti Jha1, Bhagyaraj J1, Suraj Toppo2, Rajkumar Singh2, Asim Tewari1, Sushil Mishra1 1Indian Institute of Technology Bombay, Mumbai, India. 2KCTI, Bharat Forge Limited, Pune
Forging of alpha-beta Ti-6Al-4V alloy having lamellar microstructure
at slower strain rates and just below transition temperature
produces the globular microstructure, which can be further heat
treated to obtain the bimodal (equiaxed and lamellar)
microstructure. The degree of deformation also governs the extent
of formation of globular microstructure. To understand the
influence of deformation on the microstructure evolution, a range of
compression tests have been carried out at 20%, 50% and 80%
deformation, at strain rate of 0.1s-1 and temperature 950℃. The
shearing of alpha lamellae under the compressive loading is
apparent for 20% deformation. The shearing of lamellae is more
intense for 50% deformation that produces the globular
microstructure. The decreasing trend of the flow stress with the
strain, can be interpreted by globularisation, dynamic
recrystallization and texture evolution. There is marked increases in
the flow stress after 60% deformation has been observed. To
characterize the increase in the flow stress after 60% deformation
further test has been carried out for 80% deformation. The
metallographic examination for 80% deformed specimen shows the
reappearance of lamellar structure, though in smaller grain size. The
TEM micrograph reveals the twinning as the other deformation
mechanism for the highly deformed Ti-6Al-4V with initial lamellar
microstructure.
Microstructural and texture characterization and 3D modeling of Ti-6Al-4V alloys with different processing histories Sudipto Mandal1, Jacky Lao1, Vahid Tari1, D.S. Shih2 and Anthony D. Rollett1 1Carnegie Mellon University, Pittsburgh, PA, USA. 2Boeing Research and Technology, St. Louis, MO, USA.
This work explores the processing-microstructure-property
relationships in two-phase titanium alloys such as Ti-6Al-4V that are
used for aerospace applications. The motivation is reduction of the
buy-to-fly ratio of titanium alloys. Microstructures produced by the
conventional Vacuum Arc Remelting (VAR) method are compared
with the relatively new Electron Cold Beam Hearth (EBCH) melting.
Microstructure and texture of the two sources of materials are
characterized using Scanning Electron Microscopy (SEM), X-Ray
Diffraction (XRD) and Electron Backscatter Diffraction (EBSD). To
model their properties, three-dimensional synthetic digital
microstructures are generated based on the experimental
characterization data. An open source software package,
DREAM.3D, is used to create heterogeneous two-phase
microstructures that are representative of titanium alloys. Crystal
plasticity models based on the fast Fourier transform algorithm (FFT)
are used to simulate the deformation response of the material at
both microscopic level and continuum level. A data driven approach
is followed to understand and model the processing-microstructure-
property relationships in Ti-6Al-4V alloy.
ABSTRACTS MONDAY PM - DEFORMATION 31
Study of residual stresses in Ti-7Al using theory and experiments K. Chatterjeea, A. J. Beaudoina, J.Y.P. Kob, H. Philippd, J. Beckerb,d, P. Purohitd, S. M. Grunerb,c,d,e
aMechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 West Green Street, Urbana-Champaign, IL 61801, USA. bCornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14853, USA. cDepartment of Physics, Cornell University, 109 Clark Hall, Ithaca, NY 14853, USA. dLaboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853, USA eKavli Institute for Nanoscale Science, Cornell University, Ithaca, NY 14853, USA
Finite element simulations are carried out to follow the evolution of
residual stresses in Ti-7Al (hcp) alloy, as developed through a
process of combined bending and tension. A virtual polycrystal
geometry is generated using the position and orientation
information of the grains. This information is obtained from High
Energy Diffraction Microscopy (HEDM) experiments performed at
the Advanced Photon Source of Argonne National Laboratory. A
finite-element model using mesoscopic field dislocation mechanics
[1] is employed to simulate the deformation history of bending,
tension and unloading. The difference between the applied and the
experimental bending stresses are used to initialize a field of
geometrically necessary dislocations in the simulation. Strain rate
sensitivities of prismatic and basal slip systems of Ti-7Al are
evaluated from high energy x-ray diffraction data collected during
stress relaxation situation and are used as input to the simulation. A
separate set of HEDM experiments are performed for determination
of the strain rate sensitivities of different slip systems of Ti-7Al.
These experiments are conducted at the Cornell High Energy
Synchrotron Source (CHESS) and diffraction spots are collected using
a prototype mixed mode pixel array detector with CdTe sensor [2,3]
– a fast detector capable of capturing images at a maximum rate of 1
kHz. Conclusions from this combined experimental and simulation
work are that grains deform mainly via prismatic slip, and accurate
characterization of grain orientations and rate-sensitivity are needed
to model the development of grain-level residual stresses.
[1] A. Roy, S. Puri & A. Acharya (2006) Modelling and Simulation in Materials Science and Engineering. 15, S167.
[2] M.W, Tate, D. Chamberlain, K.S. Green, H.T. Philipp, P. Purohit, C. Strohman & S. M. Gruner (2013) Journal of Physics: Conference Series. 425, 062004.
[3] J. Becker, M.W. Tate, K.S. Shanks, H.T. Philipp, J.T. Weiss, P. Purohit, D. Chamberlain, J.P.C. Ruff, S.M. Gruner (2016) Journal of Instrumentation. 11, P12013.
ABSTRACTS MONDAY PM – RUDY WENK 32
Symposium W: A Celebration of the Contributions of Rudy Wenk Symposium Chairs:
Dr. Lowell Miyagi, Geology & Geophysics, University of Utah
Dr. Pamela C. Burnley, Department of Geoscience, University of Nevada, Las Vegas
Dr. Sven Vogel, Los Alamos National Laboratory
Texture analysis from synchrotron and Neutron diffraction: Rietveld method applied to biological materials, commercial-pure Titanium and Shales from sedimentary basins I. Lonardelli1, L. Lutterotti2, M. Bortolotti2 and HR. Wenk3 1Comar SpA via G. Galilei 266, Zimella (VR), Italy. 2Dipartimento di Ingegneria Industriale, Università di Trento, Italy. 3Department of Earth and Planetary Science, University of California, Berkeley, CA 94720, USA
The analysis and the precise characterization of anisotropy in
geophysics as well as in materials science is crucial in order to have a
complete understanding of all the aspects related to plastic
deformation occurred in a wide range of materials.
From several years, synchrotron and neutron diffraction techniques
helped us to investigate at the micro and nano-scale level the
preferred orientation of sub-domains in a significant volume of
matter analyzed. The Rietveld method was implemented and
applied by Prof. Wenk and his research group in order to obtain
quantitative and reliable information regarding not only texture but
also the structure and microstructure that are averaged over the
experimentally sampled volume.
Here we present three different fields in which the method was
applied to determine quantitatively the crystallographic texture:
mineralized biological samples with hydroxyapatite fabric [1],
commercial pure Titanium during high temperature phase
transformation/recrystallization process [2] and very oriented multi
phases Shales with complex crystal structures [3].
[1] I. Lonardelli, HR. Wenk, L. Lutterotti J. Synchrotron, Rad. 12, (2005), 354-360.
[2] I. Lonardelli, N. Gay, HR. Wenk, M. Humbert, S.C. Vogel and L. Lutterotti Acta Mater. 55 (2007) 5718-5727.
[3] I. Lonardelli, HR. Wenk, Y. Ren Geophysics (2007), Vol.72, n° 2, p. D33-D40.
Olivine-antigorite phase transformation: microstructures, phase boundary misorientation and seismic properties L. F. G. Morales1, D. Mainprice2 and H. Kern3 1ETH Zurich, ScopeM, Zurich, Switzerland. 2 Geosciences Montpellier, Montpellier, France.
Antigorite-bearing rocks are thought to contribute significantly to
the seismic properties in the mantle wedge of subduction zones.
Here we present a detailed study of the microstructures and seismic
properties in a sample of antigorite-olivine schist. We have
measured crystallographic orientations and calculated the seismic
properties in three orthogonal thin sections. Microstructures
indicate that deformation is localized in the bands with high
antigorite fractions, resulting in strong crystallographic preferred
orientations (CPOs) with point maxima of poles to (100) parallel to
lineation and poles to (001) to the foliation normal. Olivine CPO
suggests deformation under high temperature and low stress, with a
[100] fibre texture. The CPO strength varies with grain size, but is
strong even in fine-grained antigorite, and larger grains tend to
display higher internal misorientation. Phase transformation
relationships between olivine and antigorite are evident in phase
boundary misorientation analysis, (100)ol||(001)atg being more
frequent than [001]ol||[010]atg. Two new phase transformation
relationships between olivine and antigorite, with a relationship to
deformation has been documented. Seismic velocities decrease
while anisotropy increases with increasing antigorite modal content.
Antigorite grain shape has a weak effect on seismic velocities, but
affects the anisotropy. While CPO-derived seismic velocities agree
well with ultrasonic measurements for sections parallel to the
foliation determined for the same sample, they are between 0.2-1.0
km/s faster than ultrasonic velocities measured normal to the
foliation. The slower ultrasonic velocities possibly result from
attenuation on grain boundaries and voids that may remain open
even at pressures of 600 MPa.
The seismic properties of quartzites during the alpha-beta transition and the influence of texture David Mainprice1, and H. Kern2 1Géosciences Montpellier UMR CNRS 5243, Bâtiment 22, CC 060, Université de Montpellier,Place Eugène Bataillon, 34095 MONTPELLIER cedex 05, France. 2Institut fur Geowissenschaften, Universität Kiel, Kiel, Germany
The preferred crystal orientation (texture) of quartz is characteristic
for many quartz-bearing rocks such as quartzite and granite.
Quartzite has been the subject of texture analysis for nearly 100
years. One of fascinating aspects of quartz is the alpha-beta phase
transition that has a very strong impact on elastic properties and
therefore also on anisotropic seismic properties quartz-bearing
rocks in the Earth’s continental crust. Seismologists have claimed in
recent years that they detect a velocity drop in the crust that they
interpret as the alpha-beta transition. Their analysis is entirely
elastically isotropic, but we know that quartzites typically have
strong texture and hence will have anisotropic elastic properties.
In this presentation we will present a digital model of the anisotropic
elastic properties of quartz alpha-beta transition. Firstly, the model
will be tested against experimental ultrasonic measurements at
temperature and pressure on quartzites. Secondly, we will quantify
the anisotropic seismic properties for several quartzites with
different textures at various pressure and temperature conditions
corresponding to the depth range in the Earth’s crust of 15 to 17 km
where seismologists have claimed to observe the alpha-beta
transition in-situ.
ABSTRACTS MONDAY PM - RECRYSTALLIZATION 33
Symposium R: Crystallization, recrystallization and growth textures Symposium Chairs:
Dr. Rodney McCabe, Los Alamos National Laboratory
Asher Leff, Department of Materials Science and Engineering, Drexel University
Effects of Nucleation at Shear bands on Texture Evolution in Cold-Rolled IF Steels H. Miura1, M. Kobayashi1, T. Tsuji1, H. Minami2 and Y. Funakawa2 1Department of Mechanical Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi, Aichi, 441-8580, Japan. 2Sheet Products Research Dept., Steel Research Laboratory, JFE Steel Corporation, 1 Kawasaki-cho, Chuo-ku, Chiba 260-0835, Japan
Cold-rolled IF steels with added 25 and 41ppm C, which initial grain
sizes before cold-rolling were 57 and 34 m respectively, were
annealed to investigate static recrystallization (SRX) nucleation
behavior and the effects on texture evolution. Observations from
transverse direction (TD) revealed development of obvious amount
of shear bands to subdivide pancake grains that induced
misorientation distribution in the cold-rolled samples. SRX
nucleation occurred preferentially at grain boundaries and shear
bands. Softening due to onset of SRX looked to be more affected by
initial grain size and deformation microstructure rather than the
amount of C content. That is, onset of SRX was earlier in the excess C
added IF steel with initial grain size of 34 m than that in the
conventional one with 57 m, while the apparent activation energy
was around 300 kJ/mol in both samples. SRXed grains formed at
shear bands possessed rather large misorientations to the mother
grains, which implies occurrence of discontinuous SRX. These results
indicate the important role of shear banding as well as initial grain
size on SRX behavior. In the process to full recrystallization,
however, they were eroded by (111) grains to form strong (111)
texture.
Texture development during static recrystallization of a warm and hot rolled ferritic stainless steels A. Després1, C.W. Sinclair1, J-D. Mithieux2, F. Chassagne2
1Department of Materials Engineering, University of British Columbia, Vancouver, Canada V6T 1Z4. 2 Aperam Research Center, BP 15, 62230 Isbergues, France
The effect of static recrystallization on the texture development of
hot rolled ferritic stainless steels is presented, with a focus on the
mechanisms of nucleation and growth leading to the deleterious α
fibre texture. Industrial transfer bars were rolled to thickness
reductions of 50% and 75%, at 700°C (warm rolling) and 1100°C (hot
rolling), then annealed at 950°C. As the rolling temperature
increases, the recrystallization texture following annealing exhibits a
transition from a γ fibre texture to a “spread” α fibre texture
(comprising orientations between {001}<110>, {112}<110> and
{100}<001>). In warm rolled products, a “classic” in-grain nucleation
of γ fibre grains at shear bands is observed. In hot rolled products,
regardless of the reduction, nucleation occurs by bulging of α fibre
subgrains at pre-existing grain boundaries. This preferred
development of α fibre grains is associated with the absence of
shear bands (even at high reductions), thus leaving pre-existing grain
boundaries as the only possible nucleation sites.
Quantification of recrystallization simulation datasets by chord length distribution and principal component analysis M.I. Latypov1, M. Kühbach2, I.J. Beyerlein1, and S.R. Kalidindi3 1University of California Santa Barbara, Santa Barbara, USA. 2Max-
Planck-Institut für Eisenforschung GmbH, Düsseldorf, Germany. 3Georgia Institute of Technology, Atlanta, USA.
Understanding such complex phenomena as recrystallization
requires integrated investigation approaches combining
experiments and simulations. The development of advanced
characterization and modeling methods provides for access to ever
increasing amount of hierarchical microstructural information. For
example, modern highly parallelized approaches allow for simulating
rare but statistically significant nucleation events under rigorously
controlled conditions by monitoring millions of nucleation
candidates. Such rich datasets demand efficient microstructure
quantification protocols that will help detecting salient
microstructural features and facilitate establishing quantitative
relationships between the microstructure of the material, its
properties, and processing conditions.
In this talk, we present a microstructure quantification framework
based on higher-order statistical descriptions and dimensionality
reduction techniques suitable for both experimental and simulation
datasets. It will be shown, as a specific example, that directionally
resolved chord length distribution in combination with principal
component analysis allows for quantification of recrystallization
datasets capturing microstructural features beyond widely used
first-order descriptions (e.g., mean grain size). The potential of the
framework to serve as a basis for quantitative processing–structure–
property relationships and efficient visualization of microstructure
databases is also discussed.
ABSTRACTS MONDAY PM - ENGINEERING 34
Symposium A: Texture and Anisotropy in Advanced Engineering Processes and Materials Session: Advanced Materials
Symposium Chairs:
Professor Tracy Nelson, Department of Mechanical Engineering, Brigham Young University
Dr. Ashley Spear, Department of Mechanical Engineering, University of Utah
Microstructure and Texture evolution during thermo-mechanical processing of low-symmetry metals R.J. McCabe1, M. Zecevic2, C.A. Miller1, D.R. Coughlin1, B. Clausen1, S.C. Vogel1, M. Knezevic2, D.W. Brown1, D.J. Alexander1 1Los Alamos National Laboratory, Los Alamos, NM, USA. 2Univerity of New Hampshire, Durham, NH, USA.
Thermo-mechanical processing of low-symmetry metals typically
results in anisotropic microstructures and properties that can vary
across a component and adversely affect performance. For
instance, residual stresses that develop in formed and heat treated
components with varying texture and anisotropic thermal expansion
behavior can cause components to warp during machining
operations. Here we use neutron diffraction and electron
backscatter diffraction to study the variation in local texture as a
function of processing path. We first examine the effects of
different clock-rolling schedules, where plates are rolled at 0, 90,
225, and 315 orientations to a total reduction of 25%, but with
different combinations of reduction per step. The plates are then
formed into hemispherical components and texture measurements
are made as a function of position. As expected, the texture varies
from pole to equator, but there are also considerable texture
differences longitudinally about the component due to the initially
anisotropic clock rolling textures. In addition, there are significant
texture differences measured from the inside radius to the outside
radius of the component. These results are compared to modeling
efforts that incorporate the VPSC polycrystal plasticity model with
finite element simulations.
Reactive Texturing of Y-TZP and Ce-TZP in a 17 Tesla Magnetic Field O. Van der Biest1, D. Vriami1, E. Beaugnon2 1Department of Materials Engineering, K.U.Leuven, Belgium. 2Laboratoire National des Champs Magnétiques Intenses (LNCMI), Grenoble, France.
Tetragonal zirconia powder cannot be aligned by applying a strong
magnetic field during green forming of a powder compact. In prior
work we have shown that a strong texture can be achieved in 3Y-TZP
by using a reactive texturing technique. One uses a suspension that
contains monoclinic zirconia that can be oriented in a strong field
during green forming for instance by slip casting. The monoclinic
(100) plane is oriented perpendicular to the magnetic field direction.
When a mixture of pure monoclinic zirconia powder and 8 mol%
yttria co-precipitated zirconia is used, a strong texture of single
phase 3Y-TZP is obtained after reactive sintering for 3 hrs at 1650°C.
The (001) plane of the tetragonal phase is perpendicular to the
magnetic field direction, i.e., the c-axis is aligning parallel to the
field. In the strong magnetic field of 17.4 T used in the present work,
the texture of the cast green ceramic, can be measured (Lotgering
factor f = 0.15) whereas at lower fields texture in the green body is
barely discernible. After sintering a Lotgering factor of 0.8 is
measured. More detailed analysis of the texture showed a texture
index of 32.5.
We attempted to texture Ce-TZP by a similar strategy but with less
success. The suspension consisted of a mixture of monoclinic
zirconia and nanometric ceria powder. Orienting the monoclinic
zirconia particles during slip casting was again clearly achieved with
a Lotgering factor of 0.3 calculated from the monoclinic reflections
again with the (100) plane normal to the magnetic field. After
reactive sintering a single phase tetragonal microstructure is formed
if the sintering temperature is chosen high enough. However, the
resulting Lotgering factor for the 001 reflections was only 0.3 and a
texture index of about 3 was measured.
It appears that for successful reactive texturing of zirconia the
differences in composition between the monoclinic phase and the
phase containing the stabilizing element should be as small as
possible.
Texturation of polycrystalline NiMnGa alloys via mechanical training studied by in-situ neutron diffraction and SEM EBSD Y. D. Zhang1, 2, Z. B. Li3, N. F. Zou1,3, W. M. Gan4, M. Hofmann5, X. Zhao3, C. Esling1, 2 and L. Zuo3 1Laboratoire d'Étude des Microstructures et de Mécanique des Matériaux (LEM3), CNRS UMR 7239, Université de Lorraine, Metz, France. 2Laboratory of Excellence on Design of Alloy Metals for low-mAss Structures (DAMAS), Université de Lorraine, Metz, France. 3Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang, China. 4German Engineering Materials Science Centre (GEMS), Helmholtz-Zentrum Geesthacht (HZG) Outstation at FRM II, Garching, Germany. 5Forschungsneutronenquelle Heinz Maier-Leibnitz(FRMII),TUMünchen, Garching, Germany.
Studies have revealed that the martensite of intermetallic NiMnX
(X=Ga, In, Sn), especially NiMnGa alloys, with crystal structure
modulation exhibit strong reversible deformation capacity under an
applied force. This capacity is originated from the abundant twinning
or shuffling systems of each martensite variant. For NiMnGa with
7M modulated martensite, the activation of various deformation
systems and their influences on microstructure have not been
sufficiently studied. The present work presents a thorough
investigation on these issues. A NiMnGa alloy with 7M modulated
martensite at room temperature was compressed and the
deformation process was investigated by in-situ neutron diffraction
and SEM EBSD, respectively. It is revealed that the 7M martensite
possesses various new twinning and shuffling systems in addition to
the conventional twinning systems, and all can be activated to
achieve variant reorientation. The activation of the conventional
twinning systems results in volume fraction change of the existing
variants, whereas the activation of the new twinning or shuffling
systems gives rise to the formation of new 7M variants or NM
ABSTRACTS MONDAY PM - ENGINEERING 35
martensite. Via the reorientation of the variants, the alloy is finally
textured with the <010> direction of all martensite variants parallel
to the compression direction. The results of the present study
provide comprehensive information on the deformation
mechanisms of NiMnGa 7M martensite.
Role of Texture on Enhanced Magnetocaloric Effect in Heusler Alloys Following Stress Assisted Thermal Cycling Michael V. Mcleod1, Bhaskar S. Majumdar2, Zafer Turgut1, and Sven Vogel3 1AFRL, Wright Patterson AFB, Ohio 45433, 2New Mexico Tech, Socorro, NM 87801, 3Los Alamos National Laboratory, NM 87545
Heusler alloys of the type X2YZ type often exhibit unique structural
and magnetic response, which manifest in magnetic shape memory
behavior as well as large magnetocaloric effect (MCE), the latter
being important for non-polluting solid state refrigeration. In these
alloys, X and Y belong to 3d transition metals with one of them
dominating the magnetic moment, and Z is an element in the IIIA-VA
group. They generally possess wide solid solubility, such that non-
stoichiometry as well as elemental substitution can alter the
martensite stability as well as magnetic exchange interactions
between atomic sites, causing a strong coupling between two first
order transformation temperatures, namely structural (TM) and
magnetic transformations (TC). Under such situations, a magnetic
field can bring about a structural transformation, known as
magnetostructural transformation, which manifests in large or
‘giant’ MCE.
The focus of this work was on two variants of Ni2MnGa alloys,
where the Ni:Mn ratio in non-stoichiometric composition or Cu
substitution at the Mn site at stoichiometric composition were
utilized to bring the magnetostructural transformation close to room
temperature (RT). Specific alloys that we refer to had compositions:
(a) Ni2Mn0.76Cu0.24Ga, and (b) Ni54Mn21Ga. In the former case,
substitution of Cu has been shown to increase martensite start
temperature (Ms) from 200 K to 321 K, while the Curie temperature
TC was simultaneously decreased from 376 K to close to Ms. The
transformation temperatures for alloy (b) were similar. Alloy (a)
exhibited a martensitic structure at RT that was dominated by body
centered tetragonal (bct, I4/mmm) phase along with minor (10%)
7M (C2/m:b3) modulated monoclinic structure, while the Heusler
austenite phase was described by the ordered fcc (Fm3 m) structure.
Correspondingly, alloy (b) exhibited a fully bct structure in the
martensite state at RT. The MCE values for the two alloys were
approximately -10 J/kg-K for an imposed magnetic field change of 2
Tesla. It is important to note that the easy magnetization axis for
these anisotropic alloys is along the (110) pole of the bct martensite
structure, and that the as processed heat treated material often
have high starting texture along the columnar direction although not
along the easy magnetization axis.
In an effort to enhance MCE, thermal cycling was conducted
between the fully austenite state and martensitic states under a
constant low compressive stress. The rationale was to maintain
integrity of the samples while at the same time imparting (110) pole
texture along the columnar direction, which was also the direction
of the applied magnetic field. Contextually it has been shown in NiTi
alloys that such stress assisted thermal cycling (SATC) using low
superimposed stress are highly efficient in predictable enhanced
texture. In the cycled sample, large increases in MCE of -25 J/kg-K
and -18 J/kg-K were observed for samples (a) and (b), respectively;
i.e., increases 150% and 80%. These significant increases are
correlated with the preferential texture measured using the HIPPO
neuron diffraction apparatus at LANSCE. It is believed that favorable
twin variants reduce pinning of magnetic domains resulting in
enhanced MCE following SATC. The structural and texture changes
are discussed in detail.
ABSTRACTS MONDAY PM - CHARACTERIZATION 36
Symposium C: Texture and Microstructure Characterization Symposium Chairs:
Dr. Irene Beyerlein, Department of Mechanical Engineering, University of California, Santa Barbara
Dr. Mukul Kumar, Lawrence Livermore National LaboratoryIn-house texture measurement using compact neutron source
M. Takamura1, Y. Ikeda 1, H. Suzuki2, M. Kumagai3, Y Oba4, T. Hama4 and Y. Otake1 1RIKEN, Wako-shi, Japan. 2JAEA, Tokai-mura, Japan. 3tokyo City University, Tokyo, Japan. 4kyoto University, Kyoto, Japan.
A compact accelerator-based neutron source has never been applied
to a texture measurement with neutron diffraction because of its
low neutron flux. However, authors have lately succeeded in
measurement of the diffraction pattern from a ferritic steel using
Riken Accelerator-driven Compact Neutron Source (RANS) [1], and
then applied it to the measurement of texture evolution due to
plastic deformation for steel sheets. In this study, pole figures of IF
(interstitial free) steel sheets with the thickness of 1 mm, including
an as-received sample and plastically deformed samples, were
successfully obtained through neutron diffraction experiments by
suitable experimental arrangements in RANS. The total
measurement time for sixty diffraction patterns to acquire one pole
figure was only 300 minutes. The pole figures obtained by RANS
exhibit typical tendencies in the texture evolution of an IF steel,
which shows the capability of the in-house compact neutron source
for the analysis of plastic deformation mechanism in conjunction
with texture. The possibility to expand the application of the in-
house compact neutron source to the investigations in crystal
plasticity model will also be discussed.
[1] Y. Ikeda, et al. (2016) Nuclear Inst. and Methods in Physics Research, A, 833, 61.
Texture analysis with monochromatic neutrons at STRESS-SPEC W.M. Gan1, M. Hofmann2, H.-G. Brokmeier1,3 1Gemern Engineering Materials Science Center at MLZ, Garching, Germany. 2FRM II, TU München, Garching, Germany. 3Intitute of Materials Science and Engineering, Clausthal University of Technology, Clausthal-Zellerfeld, Germany
The engineering materials science diffractometer STRESS-SPEC at
FRM II (Garching, Germany) is designed to be applied equally to
texture and residual stress analyses by virtue of its very flexible
configuration [1]. Due to its high penetration of neutrons and
comparably high neutron flux STRESS-SPEC allows a combined
analysis of global texture, local texture, strain pole figure and FHWM
pole figure in a wide variety of materials including metals, alloys,
composites, ceramics and geological materials.
In order to obtain good statistics and use the limited beam time
efficiently, a continuous scan routine has been developed for pole
figure measurement which saves about 30% positioning time
compared to step size scan. A method using dual wavelength
produced by PG monochromator has been optimised for pole figure
measurement of single phased metals. Moreover, a robot is used as
a sample changer and Eulerian cradle substitute which greatly
enhances the capabilities for standard pole figure measurement and
as well as local texture analysis on irregular shape samples [2, 3]. As
a future development it is planned to implement a second area
detector which will double the 2-theta coverage angles (together up
to 30°) to further speed up data acquisition time. In this contribution
we will present all these methods for pole figure measurements
with specified related examples.
[1] M. Hofmann, W.M. Gan, J. Rebelo-Kornmeier & M. Schoebel (2013) Neutron News. 24, 14.
[2] H.-G. Brokmeier, W.M. Gan, C. Randau,. M.Voeller, J. Rebelo-Kornmeier & M. Hofmann (2011) Nucl. Instr. Meth. A642, 87.
[3] C. Randau, H.-G. Brokmeier, W.M. Gan, M.Voeller, M. Hofmann. W. Tekouo, N.AL-hamdany, G. Seidl & A. Schreyer (2015) Nucl. Instr. Meth. A794, 67.
Development and verification of simultaneous measurement system for texture and phase fraction by time-of-flight neutron diffraction at iMATERIA Y. Onuki1, A. Hoshikawa1, S. Sato1, S. Nishino1, T. Ishigaki1 and T. Tomida2 1Frontier Research Center for Applied Atomic Sciences, Ibaraki University, Tokai, Japan. 2Ibaraki Prefectural Government, Tokai, Japan.
Neutron diffraction is a powerful tool for investigations of metallic
materials because neutron interacts not only with the surface layer
but also with whole exposed volume. This is especially advantageous
to analyze the statistic properties, e.g., texture, phase fraction and
dislocation density. By using TOF (time-of-flight) type neutron
diffraction, statistically reliable measurement is possible in a simple
sample environment in short time duration. We have previously
developed the texture measurement scheme at iMATERIA, the 20th
beamline at J-PARC MLF [1]. By using Rietveld texture analysis
technique, texture of each phase in a multiphase material can be
determined [2]. It is possible to obtain the phase fraction as well as
the texture in the analysis. In the current study, we verify the
accuracy of the phase fraction analyzed by the Rietveld texture
analysis. The “multiphase” model samples were prepared by
laminating 20 sheets of ferritic (AISI 430) and austenitic (316L)
stainless steels of 0.3 mm thickness. By changing the number and
width of the austenitic steel in the lamination, the true fraction of
austenite was clearly defined. The analyzed austenite fractions well
agree with the prepared fractions even if the austenite fraction is
low. For example, the analyzed values are 0.62 vol % and 2.49 vol %
for the samples with prepared fractions of 0.61 vol % and 2.47 vol %,
respectively. The texture of austenite is also successfully analyzed
although it becomes somewhat qualitative when the fraction is
below 4 vol %. In the presentation, we will also show some results of
the application to the in situ observations of phase transformation
during heat treatment as well as strain-induced transformation.
[1] Y. Onuki, A. Hoshikawa, S. Sato, P. Xu, T. Ishigaki, Y. Saito, H. Todoroki & M. Hayashi (2016) J. Appl. Cryst. 49, 1579.
[2] H. R. Wenk, L. Lutterotti & S. C. Vogel (2010). Powder Diffr. 25, 283.
ABSTRACTS MONDAY PM - CHARACTERIZATION 37
Neutron and X-ray Diffraction Texture Analysis of Novel Al-Si-Mg Alloy M. Kucerakova, L. Kalvoda, S. Vratislav and J. Capek Department of Solid State Engineering, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Trojanova 13, 120 00 Prague 2.
Texture and microstructure is analyzed on an as-casted specimen of
a novel aluminum-based alloy by means of neutron and X-ray
diffraction (XRD) method using pole figures and inverse pole figures
as the primary data. The Panalytical theta/theta X'Pert PRO
diffractometer with Cr X-ray tube and the KSN-2 neutron
diffractometer located at the research reactor LVR-15 in the Nuclear
Research Institute, plc. Rez, Czech Republic are utilized in collection
of the XRD and neutron data, respectively, followed by data
processing performed within the GSAS and X'Pert Texture SW
environment.
Elemental composition of the specimen provided by instrumental
neutron activation analysis (INAA), X-ray fluorescence (XRF) and X-
ray diffraction (XRD) phase analysis methods is dominated by Al
(79.91 wt.%), Si (9.90 wt. %), Mg (4.19 wt. %), Pb (1.1 wt. %), Fe
(0.69 wt. %) and Ca (0.175 wt. %). Aluminum (cubic, Fm3m), silicon
(cubic, Fd3m) and magnesium silicide (Mg2Si, cubic, Fm3m) phases
are identified by XRD phase analysis as the prevailing
crystallographic phases present in the sample.
Crystallographic preferential orientation analysis of these
constituting phases is then performed and discussed in relation to
other microstructure data and juxtaposed with the theoretical
considerations and simulations based on the elemental composition
of the investigated alloy.
ABSTRACTS TUESDAY AM - PLENARIES 38
TUESDAY AM PLENARY SESSION
Texture analysis of geomaterials: a challenge for EBSD David Mainprice1 1Géosciences Montpellier UMR CNRS 5243, Bâtiment 22, CC 060, Université de Montpellier, Place Eugène Bataillon, 34095 MONTPELLIER cedex 05, France.
Since 1993 Electron Back Scattered Diffraction (EBSD) has become the most popular tool for measuring texture, also called crystal-preferred
orientation in Earth Sciences. EBSD has great advantage to associate the crystal orientation data in an exact location in the microstructure. The
association of orientation and microstructure is the time-honoured method used in geology, when using the universal stage and petrological
optical microstructure. Hence it is no surprise the Earth scientists have quickly adopted the EBSD technique. The application of EBSD to
geomaterials is not as straightforward as for material sciences where synthetic polycrystalline aggregates of controlled; grain size, purity, texture,
often-single phase etc. Geomaterials samples require special sample surface preparation, problems occur because both natural and synthetic
samples often have micro-cracks due to their decompression from high pressure in the Earth or laboratory. Geomaterials typically contain several
minerals with different rates of surface polishing, so minerals have different surface heights. Perhaps the most difficult problems are related low
average atomic number than causes low diffracted intensity, typically low symmetry e.g. monoclinic, that makes indexing more complex and finally
most minerals do conduct electricity, which causes the electron beam to be deflected. Because the Earth Sciences community is small when
compared to materials science the EBSD system suppliers tend ignore some of vital needs of our community, which are; a) very sensitive cameras
with high signal to noise ratio for weak diffraction patterns, b) more reliable indexing for low symmetry crystals, and c) large area mapping as grain
size tends larger than Materials Science applications and d) eucentric SEM stages as this allows for really constant working distance, which helps
indexing performance, and finally e) beyond the Laue class indexing.
Despite all the apparent handicaps of geomaterials they are often on the cutting edge of EBSD because they are very challenging. Several new
studies are working on Ice Ih using cold stages in the SEM at -100°C, results are very encouraging for this geomaterial at the centre of climatic
concerns about the plastic flow of polar ice caps. Traditional quantitative texture analysis using EBSD data have become routine. Recent
developments on misorientation at grain boundaries in single phase or polyphase geomaterials are likely to put the emphasis on the role on grain
boundaries in future studies. To remain topical, I will select several recent topics from Geomaterials.
Relationships of microstructure and device performance in thin-film solar cells D. Abou-Ras Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin, Germany
The best performing thin-film solar cells, based on Cu(In,Ga)Se2, CdTe, or halide perovskite (e.g., CH3NH3PbI3) absorber layers, can exhibit
conversion efficiencies of more than 22%. Since in general, a thin-film solar cell consists of a thin-film stack deposited on any substrate material,
such as glass, metal, or polymer, all layers in the stack are polycrystalline. In contrast to photovoltaic devices based on multicrystalline silicon, the
device performance of solar cells with Cu(In,Ga)Se2, CdTe, or halide perovskite absorber layers is not reduced with smaller average grain sizes. At
the example of Cu(In,Ga)Se2 solar cells, it will be outlined which microstructural analyses are conducted on Cu(In,Ga)Se2 thin films, how these
analyses are combined on identical positions with electrical and optoelectronic characterization on the (sub)micrometer scale, and finally, how the
microscopic, electrical properties can be linked to the (macroscopic) device performance.
ABSTRACTS TUESDAY AM - DEFORMATION 39
Symposium D: Deformation Textures Session: Steels – Cold Rolling
Symposium Chairs:
Professor Chadwick Sinclair, Department of Materials Engineering, University of British Columbia
Professor Warren Poole, Department of Materials Engineering, University of British Columbia
Dr. Samantha Daly, Department of Mechanical Engineering, University of California, Santa Barbara
Texture, microtexture and mechanical properties of some Mn steels Satyam Suwas and R. Kalsar Department of Materials Engineering, Indian Institute of Science, Bangalore-560012, India
Deformation texture, microstructure and tensile properties have
been studied in Mn containing TWIP steel in a composition range Fe-
(32-12 Mn-0.6C). Alloys were cold rolled to a large reduction in
thickness (εt≈3). The deformed microstructure has been
characterized by X-ray diffraction and electron back-scatter
diffraction. Bulk X-ray texture reveals the development of Bs-type
texture with deformation. Microstructural features indicate the
occurrence of different deformation mechanisms at different
reduction levels. At very early stage of deformation, dislocation slip
is the dominant mechanism, at intermediate stage, deformation
takes place by twinning, and, at large strains the deformation is
governed by shear banding.
Effect of carbon addition on deformation texture of heavily cold rolled polycrystalline Fe-3%Si Haruhiko Atsumi1, Shuichi Nakamura2 1Nippon Steel & Sumitomo Metal Corporation, Technical Research & Development Bureau, Hirohata R & D Lab., Hyogo Prefecture, Japan. 2Nippon Steel & Sumitomo Metal Corporation, Steel Research Laboratories, Chiba Prefecture, Japan
Deformation textures of heavily cold rolled polycrystalline Fe-3%Si
with 0.0007, 0.002, 0.01, 0.02 mass%C were investigated, in order to
clarify the effect of carbon addition on development of α-fiber
components {100}<011>. The deformation textures of 90% cold
rolled specimens were measured by X-Ray diffraction technique.
Each texture was basically characterized by strong α-fiber and week
γ-fiber components. In addition, the peak intensity of α-fiber
components shifted from {211}<011> to {100}<011>, as increased
amount of carbon addition. According to Taylor’s pencil glide model
proposed by Dillamore and Katoh, {211}<011> is the most stable
orientation in α-fiber components against ideal rolling deformation.
However, in the case of rolling deformation considering width strain,
the orientation rotation from {211}<011> to {100}<011> could be
suggested by the above model. Actually, focused on the macroscopic
deformation, the width of cold rolled specimens increased, as
increased amount of carbon addition. Therefore, we performed
electron back-scattered diffraction (EBSD) measurements of the cold
rolled specimens to identify the origin of the width increasing as the
effect of carbon addition. As a result, the orientation rotation from
{211}<011> to {100}<011> was revealed to be frequently observed
on width edge in deformed grains which were deformed to not only
rolling direction but also width direction by EBSD measurements.
The peak-shift from {211}<011> to {100}<011> with increasing
amount of carbon addition occurred due to that the solute carbon
and FeC precipitates suppressed the deformation in the dolling
direction and activated the slip systems which induced α-fiber
oriented grains to deform in the width direction.
Formation of High Angle Boundaries during Cold-rolling of Ti-added Ultra Low Carbon Steel T. Morikawa1, S. Kira1, K. Fukuda1, M. Tanaka1, K. Higashida1, K. Kimura2, K. Murakami2, K. Ushioda2 1Kyushu University, Fukuoka, Japan. 2Nippon Steel & Sumitomo Metal Corporation, Futtsu, Japan.
Development of deformation microstructures due to cold rolling in
ultra-low carbon steel has been investigated by same sites
observation in the longitudinal plane of rolled sheet by SEM and
SEM-EBSD technique with the increase of thickness reduction.
Particular attention has been paid to the process of the grain
subdivision during the cold-rolling and the formation of new high
angle boundaries in initial grains. The microstructures and the
orientation distribution in the longitudinal plane of the specimen
rolled by 50% reduction in thickness were observed, then the sheet
was subjected to additional rolling, where the sheet was fitted into a
frame made by the same steel in order for the observed longitudinal
plane to deform under a plane strain condition. Some initial grains
were divided into parts elongated along the rolling direction with
formation of slip bands after the additional rolling. SEM-EBSD
analysis revealed that the crystallographic orientation of the divided
parts in the grain gradually rotated with the increase of thickness
reduction. The rotation occurred during rolling contributes the
formation of new boundaries in the initial grain. It is also notable
that fine grains were observed around the new boundaries. The
results suggest that the activation of slip in the grain due to cold-
rolling was enhanced by the constraint of neighboring grains as well
as by the stress factor.
.
ABSTRACTS TUESDAY AM – RUDY WENK 40
Symposium W: A Celebration of the Contributions of Rudy Wenk Symposium Chairs:
Dr. Lowell Miyagi, Geology & Geophysics, University of Utah
Dr. Pamela C. Burnley, Department of Geoscience, University of Nevada, Las Vegas
Dr. Sven Vogel, Los Alamos National Laboratory
Quartz textures in rocks – progress in methodology, results and interpretations Karsten Kunze, Luiz F.G. Morales
ETH Zurich, ScopeM, Zurich, Switzerland
Quartz is a common rock-forming mineral, and certainly the mineral
studied most in texture analysis of rocks. There is hardly any texture-
analytical method that had not been applied to identify quartz
fabrics in a diversity of rocks. As a consequence, a broad range of
texture types and preferred orientation patterns have been
reported. Many of them are reasonably well explained and used for
phenomenological interpretations to infer deformation conditions of
rocks, others are still missing well justified understanding.
Particularly, the Y-maximum of c-axes distributions has commonly
been interpreted as due to dislocation glide on prism-a slip systems,
but none of the simulation models for polycrystalline plasticity have
convincingly succeeded to reproduce such a texture type.
This contribution will summarize the progress in methodology,
results and interpretations of quartz textures. Special emphasis will
be given to milestone contributions by Rudy Wenk over many
decades. It will be shown, that analytical methodology has advanced
to high levels of sophistication, providing data of increasing
reliability and detail. Understanding and interpretation has changed
from purely phenomenological approaches to material science like
simulations based on the underlying mechanisms. Nevertheless,
fundamental enigmas remain, some of which will be addressed.
The role of Dauphiné twinning on the development of quartz ribbons: implications for quartz superplasticity L.Lagoeiro1, R. Santos1, C. Cavalcante1, P. Barbosa2 1Federal University of Paraná, Curitiba, Brazil. 2University of Brasília, Brasília, Brazil.
Quartz ribbons in high-grade rocks from the Além Paraíba-Pádua
Shear Zone (Southeast Brazil) were analyzed using the EBSD
technique. The shear zone was developed under amphibolite to
granulite facies conditions (~660-900 °C at 700 MPa) [1]
corresponding to a depth of approximately 25 km. The rocks are
striped mylonitic gneisses where recrystallized feldspar aggregates
alternate with quartz ribbons. The analyzed thin sections were cut
parallel to the mineral lineation (elongate quartz crystals) and
perpendicular to the gneissic banding. The ribbons are highly
elongate with aspect ratios that can easily reach 20:1. Quartz
crystals show slight undulose extinction with very large subgrains
and are free of recrystallized grains. Grain boundaries are
predominantly lobate, indicating a high mobility. The c-axes of
quartz ribbons are oriented with a maximum between the Z and the
Y-direction, synthetically inclined to the dextral sense of shear of 35˚
to the Z-direction. The pole figures show features characteristic of
the Dauphiné twinning, such as the single c-axis orientation, six
rather than three pairs of positive {r} and negative {z} rhombohedral
planes. The Dauphiné twinning can be observed across a
misorientation profile in a twinning region of the ribbon with
misorientation angles at around 60˚. This can be confirmed by the
distribution of misorientation angle/axis pair relationships with a
peak at 60˚, associated with a rotation around the c-axis.
The crystallographic texture observed for the mylonitic gneiss
suggests that activation of rhombohedral planes accounts for the
plastic deformation of these rocks. Experimental, theoretical and
numerical studies are consistent with twinning acting to orient some
direction of the crystals of greater compliance parallel to the
compression direction. In this case twinning cannot accommodate
permanent deformation, but can reduce the stiffness of the crystal
to make it more deformable [2]. Our findings indicate that the
presence of Dauphiné twinning had an important influence on the
deformability of quartz during ribbon formation. The rhomb planes
of quartz are orthogonally aligned to the compression direction and,
according to the Menegon et al. [3], this crystallographic
configuration evolves to a parallelism between the directions of the
most compliant and the maximum compression. In such a position
quartz grains may have been highly deformed in a condition close to
a superplastic behavior.
[1] T.M. Bento dos Santos, J.M. Munhá, C.C.G. Tassinari, P.E.
Fonseca & D.N. Coriolano (2010) GEOSCI J. 15(1), 27. [2] J. Tullis (1970) Science 168, 1342. [3] L. Menegon, S. Piazolo & G. Pennacchioni (2011) Contrib.
Mineral. Petrol. 161(4), 635.
Microstructure and microtexture characterization of avian eggshells M. Avalos1,2, V. Tartalini2, P. Risso2, A. V. Lopez3, M. E. Hauber4, J.C. Reboreda3, R.E. Bolmaro1 1Instituto de Física Rosario, CONICET-UNR, Rosario, Argentina. 2Centro Científico Tecnológico, Lab. Microscopía Electrónica de Barrido, Rosario, Argentina. 3Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires. 4Department of Psychology, Hunter College and the Graduate Center of the City University of New York, New York, USA.
The avian eggshell is the final product of a calcium carbonate
biomineralization process. As a result, it mainly consists of calcite
crystals of different sizes and orientations. Texture and
microstructure are structural traits that influence the mechanical
properties of the eggshell. These structural characteristics are of
particular interest for evolutionary interactions in avian brood
parasitism behavior because thicker parasitic eggshells are more
resistant to punctures by hosts or conspecifics.
In this work eggshell samples of three species of avian brood
parasites (Icteridae: Molothrus) and seven hosts (Icteridae,
Tyrannidae, Cardinalidae, Mimidae, Troglodytidae) were analyzed to
characterize the microtexture and microstructure of the eggshell in
ABSTRACTS TUESDAY AM – RUDY WENK 41
order to document variation between species. Low vacuum Electron
Backscatter Diffraction (EBSD) scans were performed in the
eggshells of the selected avian species in the Radial-Tangential
planes. We complemented these scans with X ray pole figures from
the same species’ samples.
The results show that together with crystal size/thickness
relationship, the networks of grain boundaries seem to be a
microstructural characteristic to take into account for understanding
the resistance to puncturing. The analysis of EBSD results indicated
that the model of grain occupation was not sufficient to explain the
microstructure variation across different species’ eggshells.
Defining the mechanism for compaction of chondritic asteroids using EBSD-derived microtexture P.W. Trimby1,2, L.V. Forman3, N.E. Timms3, J. Goulden1 and P.A. Bland3 1Oxford Instruments Nanoanalysis, High Wycombe, UK. 2The University of Sydney, Sydney, Australia. 3Curtin University, Perth, Australia
The Allende carbonaceous chondritic meteorite, falling in Mexico in
1969, is perhaps the most extensively studied meteorite in history.
However, there is still significant debate regarding the mechanism of
porosity reduction in the primitive parent body: possible models
include gravitational compaction, hot isostatic pressing (cold
compaction followed by radiogenic heating) or impact induced
compaction. All of these mechanisms would be expected to leave a
different microstructural signature, both in terms of local
deformation microstructures and microtexture.
In this study we used large area electron backscatter diffraction
(EBSD) mapping of a sample from the Allende meteorite to examine
local texture variations in the fine-grained olivine matrix between
large (~0.5 mm diameter) chondrules. Approximately 46 million
EBSD measurements were taken at a measurement spacing of 500
nm, covering an area of ~8 mm2. The exceptional statistics within
this dataset allowed us to subdivide the matrix regions into 120 100
x 100 m grid squares, thus constraining both local and regional
texture variations.
The texture in the matrix across the sample is moderately strong but
spatially heterogeneous, dominated by a preferred <100> axis
alignment with a coupled shape preferred orientation. In addition,
significant evidence exists for non-uniform crystal plastic
deformation at the margins of the chondrules. These observations
suggest that impact-induced compaction is the most likely
mechanism for compaction of the primitive parent body of the
Allende meteorite, and demonstrate the effectiveness of EBSD-
based texture measurements for determining the mechanisms of
asteroid and meteoroid formation.
Low-temperature EBSD investigations on a BaFe2As2 single crystal A. Pukenas1, P. Chekhonin1, M. Meißner2, E. Hieckmann2, S. Aswartham3, J. Engelmann3, B. Holzapfel4, S. Wurmehl3, B. Büchner3 and W. Skrotzki1
1Institut für Strukturphysik, Technische Universität Dresden, 01062 Dresden, Germany. 2Institut für Angewandte Physik, Technische Universität Dresden, 01069 Dresden, Germany. 3Leibniz-Institut für Festkörper- und Werkstoffforschung (IFW) Dresden, 01062 Dresden, Germany. 4Institut für Technische Physik, Karlsruher Institut für Technologie, 76344 Eggenstein-Leopoldshafen, Germany.
The iron arsenide BaFe2As2 is one of the most studied high-
temperature superconductors [1]. On cooling, at TC ≈ 140 K the non-
doped BaFe2As2 undergoes a tetragonal-to-orthorhombic structural
and magnetic phase transition. The orthorhombic distortion leads to
the formation of structural domains which have been observed and
reported previously in polarized light microscopy and transmission
electron microscopy studies. However, these results are not
consistent with respect to the domain size.
A scanning electron microscope with a cryogenic sample holder was
combined with an electron backscatter diffraction technique to
achieve high spatial resolution (≤ 100 nm) and to avoid any
elaborated sample preparation prior to the analysis. The results
show domains with characteristic dimension of 0.1 μm up to few μm
and changes of domain pattern after a cooling-warming cycle.
[1] D.P. Chen & C.T. Lin (2014) Supercond. Sci. Technol. 27, 2.
ABSTRACTS TUESDAY AM - RECRYSTALLIZATION 42
Symposium R: Crystallization, recrystallization and growth textures Symposium Chairs:
Dr. Rodney McCabe, Los Alamos National Laboratory
Asher Leff, Department of Materials Science and Engineering, Drexel University
Effect of recrystallization mechanisms on twin interconnectivity and corrosion resistance in FCC metals Asher C. Leff, Austin Nye, Ryan Demott, Matthew Hartshorne, & Mitra L. Taheri Department of Materials Science and Engineering, Drexel University, Philadelphia, Pennsylvannia, USA
Thermomechanical processing can be utilized in order to control the
grain boundary character of structural metals in order to optimize
performance. In particular, the generation of interconnected twin
and twin-related boundary networks has been shown to enhance
the properties of FCC metals. This study utilized in situ heating and
electron microscopy orientation mapping techniques at multiple
length scales in conjunction with the analysis of orientation data in
order to examine the evolution of twin-related domains in copper,
brass and stainless steel during recovery, primary recrystallization
and secondary recrystallization processes. Dislocation densities were
quantified using local misorientation analysis in order to determine
the driving force thresholds for these processes. Copper was chosen
as a model FCC material and 90/10 brass was used to examine how
substitutional solutes change the stored energy requirements for
the activation of various mechanisms. 316L steel was used to study
the effects twin-related boundary connectivity on intergranular
corrosion. Twin nucleation rates were found to be independent of
recrystallization rates regardless of solute content.
Evolution of recrystallization textures in Ni-Co alloys Gyan Shankar, Satyam Suwas
Department of Materials Engineering, Indian Institute of Science Bangalore, Bangalore, India
In spite of large number of studies, there is no general theory
dealing with the evolution of microstructure and texture during
recrystallization. The present work is aimed to develop a
comprehensive understanding of the effect of deformation
heterogeneities such as deformation bands, shear bands, twins etc.
on the recrystallized microstructure and micro-texture evolution in a
face centered cubic materials. Solid solubility of cobalt in nickel is
very high and in this system it is well known that stacking fault
energy of the alloy decreases with increase in cobalt content. It
leads to formation of shear bands and twined regions after
deformation. Ni-Co alloys with different Co were rolled to 90%
reduction in thickness and subsequently annealed above
recrystallization temperature. Textures were measured by SEM-
EBSD and X-ray diffraction. The results show that microstructure of
rolled Ni-60%Co comprises of deformation bands and twins,
whereas Ni-20%Co alloy deforms by normal slip. It was found that
recrystallization starts from the region of high deformation
heterogeneities. A detailed micro-mechanism of annealing texture
formation will be presented.
Effect of Sc and Zr Addition on Recrystallization Behavior and Texture formation in Al-Mg-Si alloy K. Ikeda and S. Miura Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido, Japan.
In order to clarify the effect of scandium (Sc) and zirconium (Zr) on
recrystallization behavior and texture formation in Al-Mg-Si alloy,
microstructural observation was carried out by ex-situ and in-situ
heating SEM/EBSD methods. Al-0.5Mg-0.5Si-0.3Sc-0.2Zr (mass%)
alloy was cast, homogenized and hot-rolled at 673 K (Sample A).
Some specimens were intermediate annealed at 823 K for 6h after
hot-rolling (Sample B). And we prepared a cold-rolled Al-0.5 Mg-
0.5Si alloy (Sample C) to compare with Sample A and B. These
samples were cold-rolled into 1 mm thickness. According to previous
studies, it was found that there were many spherical and rod-like
particles, Al3(Sc, Zr), in hot-rolled sheets of Sample A. From the
results of in-situ heating SEM/EBSD analyses of Sample A, B and C, it
was found that the Al3(Sc, Zr) particles inhibited the normal grain
growth. Furthermore, the recrystallized grain sizes of these samples
were different: the grain size was large in order of Sample C, A and
B. From the viewpoint of texture formation, the annealed Sample C
had Cube and Goss orientation, while the annealed Sample A had no
preferential orientation. It was thought that Al3(Sc, Zr) can
controlled a grain size and texture of Al-Mg-Si alloys.
Evolution of micro-texture and microstructure during conventional sintering of copper N. Felege, N. P. Gurao, U. Anish Department of Materials Science & Engineering Indian Institute of Technology, Kanpur, 208016, India
Microstructural evolution of sintered materials is a well investigated
subject in powder metallurgy. However, the evolution of micro-
texture during sintering and its influence on mechanical properties
of the sintered material is not yet established. In the present
investigation the evolution of microstructure along with micro-
texture during sintering of commercially pure copper powder has
been studied. The powder was compacted using 300 MPa uniaxial
die pressure and the green compact was sintered in electric furnace
at 610 °C, 880 °C and 1020 °C in hydrogen atmosphere. The
temperatures were selected so as to obtain different dominant
densification processes comprising of grain boundary diffusion,
surface diffusion and volume diffusion respectively. Electron
backscatter diffraction indicated that there is a distinct evolution of
micro-texture and microstructure in terms of evolution of grain
boundary character distribution, misorientation and size, shape and
morphology of grains and pores. The sample sintered at 610 °C
showed a weak micro-texture unlike strong <101> fibre texture
obtained at other two temperatures indicating randomization of
orientations in the grain boundary diffusion dominated sintering.
The sample sintered at 1020 °C showed lower fraction of Sigma 3
ABSTRACTS TUESDAY AM - RECRYSTALLIZATION 43
boundaries with higher densification with rounded intergranular
pores, higher hardness and considerable grain growth indicating the
significant role of special boundaries in the sintering process.
ABSTRACTS TUESDAY AM - ENGINEERING 44
Symposium A: Texture and Anisotropy in Advanced Engineering Processes and Materials Session: Advanced Processing
Symposium Chairs:
Professor Tracy Nelson, Department of Mechanical Engineering, Brigham Young University
Dr. Ashley Spear, Department of Mechanical Engineering, University of Utah
Texture Development of Alumina Coating Processed by Aerosol Deposition M. Hasegawa1, S. Sato1, M. Komuro1, K. Kimura1, M. Tanaka2, S. Kitaoka2, Y. Kagawa3 1Yokohama National University, Yokohama, Japan. 2Japan Fine Ceramics Center, Nagoya, Japan. 3The University of Tokyo, Tokyo, Japan.
Aerosol deposition (AD) method is a coating process that can
produce ceramic coatings by impacting solid particles onto a
substrate at room temperature under low-pressure conditions [1]. It
produces dense and crystalline coating without oxidation of
substrate at room temperature. The ability to form coatings up to
several micrometers thick without any heating is one advantage of
the AD method. These coatings are considered to be fabricated by
fracture and/or plastic deformation of the particles. The coating
phenomenon is called room-temperature impact consolidation [1].
Recently, texture formation has been reported by yttria stabilized
zirconia (YSZ) and alumina coating [2, 3]. However, systematic
research on microstructure and texture evolution is still not
experimentally performed. In this study, microstructure and texture
evolution of alumina coating deposited by AD method is examined.
Alumina coatings is deposited on a mullite and molybdenum
substrate by changing the AD processes such as kinds of gas, gas
flow rate, distance between substrate and nozzle and the scanning
speed of the substrate. Alumina coatings are heat-treated from 1173
K ~ 1673 K for 1 h ~ 20 h. Microstructure observation and texture
measurement of the coating surface are done by SEM, TEM, EBSD
and XRD. The 1012, 1123, and 1126 diffracted X-ray intensities
were measured for alumina with a rhombohedral lattice. On the
basis of the obtained pole figures, the orientation distribution
function (ODF) was calculated using the arbitrarily defined cell (ADC)
method [4]. The volume fractions for the regions aligned within 15°
of the main component were calculated. Dense and crystalline
alumina coatings with the average grain size of ~ 5 nm are formed in
as-coated state. After heating the coating at 1673 K for 5 h or more,
the average grain size became ~ 300 nm. In as-coated state, fiber
texture where the (0001) plane of alumina is tilting approximately
15 degrees from the coating plane has observed. With the increase
in gas flow rate increases the volume fraction of the main
component. This texture may form by the activation of cross slips by
basal slip and pyramidal slip system of alumina during the impact of
powder to the substrate. After the heat treatment, (0001) plane of
alumina became almost parallel to the coating plane. Regarding the
ab initio methodology, it is reported that the (0001) plane is the
lowest in the surface energy. The crystal grains exist at the as-
coated coating surface and/or the grains reaching the coating
surface during grain growth under heating in which the (0001) plane
is parallel to the coating plane seem to increase preferentially to
reduce the energy of the coating formed.
Acknowledgement: This research was supported by the “Advanced
Low Carbon Technology Research and Development Program” from
the Japan Science and Technology Agency. The authors greatly
appreciate the grant.
[1] J. Akedo (2006) J. Am. Ceram. Soc. 89, 1834. [2] E. Fuchita, E. Tokizaki, E, Ozawa and Y. Sakka (2011) J. Ceramic
Society of Japan 119, 271. [3] M. Hasegawa, K. Akiyama, Y. Oki, M. Tanaka, S. Kitaoka and Y.
Kagawa (2016) Mater. Trans. 57, 1138. [4] K. Pawlik, J. Pospiech and K. Lüche (1991) Text. Microstruct. 14-
18, 25.
Transmission – EBSD on Ti/TiN Multilayer Thin-Films Tarang Mungole1, Bilal Mansoor2, Georges Ayoub2, 3, David P. Field4 1School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington USA. 2Mechanical Engineering Program, Texas A & M University, Doha, Qatar. 3Industrial and Manufacturing Systems Engineering Department, University of Michigan, Dearborn, Michigan USA
Metal-ceramic multi-layered thin film systems comprising of
alternating layers of Ti and TiN were fabricated using a physical
vapor deposition (PVD) technique on a p-type (100) Si wafer.
Samples with different period thicknesses of Λ = 20 nm, Λ = 10 nm
and Λ = 5 nm were produced. Films of pure Ti and pure TiN were
fabricated as reference samples. Automated transmission
backscatter diffraction (t-EBSD) performed in FEI Sirion scanning
electron microscope at an accelerating voltage of 30 KeV, spot size
of 6, working distance of ~ 3 mm and a tilt angle of ~ -35o produced
indexable Kikuchi patterns from pure Ti thin-films deposited at 550 K
having ~ 80 nm lateral grain size. Sample preparation involved
reactive ion-etching of the Si wafer substrate to create windows of
freestanding Ti thin-films. t-EBSD of Ti thin-films revealed existence
of {0001} basal texture. Texture information from the Ti/TiN multi-
layered thin-film composite via t-EBSD will be also be presented.
Inhomogeneities in strained epitaxial BaFe2As2 thin films P. Chekhonin1, J. Engelmann2, M. Langer3, B. Holzapfel3, C.-G. Oertel1 and W. Skrotzki1 1Institut für Strukturphysik, Technische Universität Dresden, Dresden, Germany. 2 Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden, Dresden, Germany. 3 Institut für Technische Physik, Karlsruher Institut für Technologie, Eggenstein-Leopoldshafen, Germany.
Strained BaFe2As2 thin films have been grown by pulsed laser
deposition on MgAl2O4 spinel substrates using thin iron buffer layers
to achieve epitaxy. The microstructure was characterized in a
scanning electron microscope applying the high resolution electron
backscatter diffraction and the electron channeling contrast imaging
technique.
ABSTRACTS TUESDAY AM - ENGINEERING 45
Very small lattice rotations (≤ 0.2°) and strain inhomogeneities on
length scales of 100 nm or even below dominate the microstructure
[1]. Partially strain relaxed areas with in-plane dislocations were
observed in BaFe2As2. Additionally, the results indicated that the
iron buffer layer crucially affects the quality of the BaFe2As2 layer.
[1] P. Chekhonin, J. Engelmann, M. Langer, B. Holzapfel, C.-G. Oertel & W. Skrotzki (2015) Cryst. Res. Technol. 50, 891.
Strong, Ductile, and Thermally Stable Mg-Nb Nanolaminates Siddhartha Pathak1*, Marko Knezevic 2, Nenad Velisavljevic 3, Manish Jain 1, Nathan A. Mara 3, Irene J. Beyerlein 3 1Chemical and Materials Engineering, University of Nevada, Reno, NV . 2Mechanical Engineering, University of New Hampshire, Durham, NH. 3Los Alamos National Laboratory, Los Alamos, NM
In recent years two-phase nanolayered composites with individual
layer thicknesses varying from 200-300nm down to 1-2 nm have
been the subject of intensive study because of their unusual
physical, chemical and mechanical properties. For example, with
decreasing layer thicknesses (down to nanometer length scales) the
mechanical response of these nanocomposites becomes increasingly
interface dominated, and they exhibit ultrahigh strengths
approaching the theoretical limit for ideal crystals. Moreover, if the
constituent phases present large differences in strength, elastic
modulus and ductility, these multilayers give rise to new possibilities
for the deformation mechanisms and properties of the composite as
a whole. In this work we explore the possibility of synthesizing
multilayered composites where one constituent phase has a low
ductility, with a final goal of enhancing both the strength and
ductility of the system.
Using physical vapor deposition (PVD) techniques we synthesized a
hexagonal close-packed (HCP) – body-centered cubic (BCC) Mg-Nb
system (where twinning in Mg leads to its lack of ductility), over a
range of layer thicknesses ranging from 5 nm to 200 nm. Testing of
such miniaturized poses significant challenges. We utilize a
combination of nanoindentation, in-situ SEM compression testing of
micro-pillars, and in-situ SEM fracture toughness testing of 3 point
bend micro-beams containing these multilayered nano-composites
to evaluate their deformation mechanisms. Micropillar testing for
three different orientations, with the interfaces oriented normal,
parallel and oblique (45o) to the compression axis, enable us to
explore the anisotropy in the mechanical response of the multilayer
system, while the fracture toughness of the specimens are
measured using the notched 3-point bend tests. These results are
compared for varying layer thicknesses as well as under varying
ambient temperatures.
Additionally, our work shows that at low enough layer thicknesses
the crystal structure of Mg can be transformed and stabilized from
simple hexagonal (hexagonal close packed hcp) to body center cubic
(bcc) at ambient pressures through interface strains. We show that
when introduced into a nanocomposite bcc Mg is far more ductile,
50% stronger, and retains its strength after extended exposure to
200 C, which is 0.5 times its homologous temperature. These
findings reveal an alternative solution to obtaining lightweight
metals critical needed for future energy efficiency and fuel savings.
Evolution of microstructure texture and mechanical behaviour of CoCuFeMnNi high entropy alloy subjected to high pressure torsion Reshma Sonkusare1, A. Kilmametov2, M. Palit2, 3, Krishanu Biswas1, N.P.Gurao1 1Indian Institute of Technology, Kanpur, India. 2Institute of Nanotechnology, Karlsruhe Institute of Technology, Germany. 3Defence Materials Research Laboratory, Hyderabad, India.
A newly developed face centre cubic single phase equiatomic
CoCuFeMnNi high entropy alloy, produced by vacuum arc melting
technique, was subjected to High Pressure Torsion (HPT). A
hydrostatic pressure of 5 GPa was applied and the thin disk
specimen were subjected to rotations of 0.1, 0.5, 1 and 5 turns.
Electron Backscatter Diffraction (EBSD) carried out at the centre of
the discs shows twinning in half turn sample and shear bands in five
turn sample. Transmission electron microscopy of the discs at the
periphery showed significant grain refinement while texture
measurement carried out at three different locations on the disk
(center, near the periphery and one between the two) using a micro-
focus X-ray source showed characteristic shear
texture.Developmentof the texture was analyzed in terms of shear
texture evolution in pure face centre cubic metals. X-ray diffraction
analysis shows the peak broadening as the number of turns
increases, without any phase transformation. Vickers hardness
reveals that hardness increases from the center of the disk to
periphery due to increase in shear strain. A correlation between
grain size, texture and hardness has been established for the newly
developed high entropy alloy. Instrumented micro-hardness tests at
different loading rate indicates an increase in activation volume with
decreasing grain size indicating the similarity in the behaviour of
single phase high entropy alloy and conventional body centre cubic
materials.
ABSTRACTS TUESDAY AM - CHARACTERIZATION 46
Symposium C: Texture and Microstructure Characterization Symposium Chairs:
Dr. Irene Beyerlein, Department of Mechanical Engineering, University of California, Santa Barbara
Dr. Mukul Kumar, Lawrence Livermore National Laboratory
Evaluation of texture using laser-ultrasonics – application to steel processing B. Hutchinson*, P. Lundin. E. Lindh-Ulmgren and P. Bate Swerea KIMAB, Box 7047, SE-16407, Kista, Sweden
The aim of this work is to develop a methodology for accessing
texture information from metals during processing, in particular
during the hot rolling of steels. This implies making measurements
on fast moving surfaces and at temperatures up to or exceeding
1000°C. The only way this can be done is with laser-ultrasonics
where instrumentation is remote from the hot metal. Texture gives
rise to elastic anisotropy and this affects the velocity of ultrasonic
waves, which can be measured with high precision. Additionally,
grain sizes can be determined from the attenuation of the ultrasonic
wave signals.
A method has been developed whereby wave velocities can be
measured in different directions through the metal plate using only
a single laser shot. These results are compared in the first stage with
predictions based on known textures, employing Voigt-Reuss-Hill
averaging of the elastic tensor. Good agreement is obtained
between predicted and measured wave velocities along different
directions in the material.
The second, more challenging, stage involves inverse modelling in
order to calculate textures from the measured signals. A finite
difference method has been developed to model the complete
signal of wave arrivals and this is applied to a range of presumptive
textures with various combinations of the harmonic coefficients C411,
C412 and C4
13. These modelled spectra are then compared with the
experimental signals using a cross-correlation procedure and the
interpolated optimum solution is found.
This approach will be presented together with examples of its
application to material tests at ambient and elevated temperatures.
Dynamical Simulations of Transmission Kikuchi Diffraction Patterns and Related Diffraction Modalities E. Pascal1, S. Singh2 and M. De Graef2 1University of Strathclyde, Glasgow, Scotland. 2Carnegie Mellon University, Pittsburgh, USA.
The size of the interaction volume in the conventional electron
backscatter diffraction (EBSD) geometry poses a limiting factor to its
resolution. This size volume can be reduced by the use of an
electron transparent sample and the acquisition of EBSPs in
transmission mode. Transmission Kikuchi diffraction (TKD) patterns
are typically acquired by mounting the thin foil, and tilting it at a
slight angle (20°-30° from horizontal) towards a standard EBSD
camera. Alternatively, a dedicated detector can be mounted
horizontally below the sample, in which case the coherent
diffraction spots will also be intercepted by the camera. The
majority of the electrons contributing to a TKD pattern originate
from the bottom portion of the sample; they are generated by
elastic scattering of electrons that were inelastically (Rutherford)
scattered before reaching the bottom portion of the foil. A realistic
TKD simulation requires that the electron energy and directional
distributions properly be taken into account; these can be
determined using Monte Carlo trajectory simulations.
We use the Bloch wave formalism to compute the electron yield as a
function of crystallographic direction in the form of a thickness
integration over the product of the modulus-squared of the wave
function (as determined from dynamical scattering simulations) and
a weighting function, 𝜆(𝐸, 𝑧), that depends on the energy, 𝐸, of the
electron as well as the effective depth, 𝑧, of its last Rutherford
scattering event. If the range of effective depth values is sufficiently
narrow, then one can employ a master pattern approach, in which
an averaged depth profile is substituted in the integration and the
dynamical simulation is carried out for all incident beam directions
distributed on the unit sphere. If the effective depth range is not
narrow, then the master pattern approach is no longer possible, and
a full (time consuming) depth and energy integration must be used
for each detector pixel.
In this contribution, we will illustrate both cases in detail. We begin
with a brief description of the implementation of the energy- and
depth-weighted dynamical scattering expression and illustrate the
similarities and differences between EBSD, ECP (Electron Channeling
Patterns), and TKD; all three modalities essentially use the same
mathematical model. Then we illustrate the realism of the pattern
simulations by comparisons with experimental patterns on a
number of material systems. Along the way, we illustrate the use of
the master pattern for a fast computation of individual diffraction
patterns. We will discuss the implementation of these simulations
in the open source EMsoft package. We will conclude this
contribution with a description and preliminary results of a more
exact (and more time consuming) implementation in which we
determine, for each detector pixel, the energy and depth
distributions of the electrons and use those to properly weight a
dynamical scattering simulation to obtain the depth- and energy-
averaged intensities. This slower approach allows for the simulation
of band contrast inversions which occur when the effective depth
distribution becomes broad; in such cases, a significant number of
electrons is generated deep inside the sample, and the dynamical
scattering processes (in particular for bands with short extinction
distances) will cause changes from the normally bright Kikuchi band
intensity profiles to dark bands on a brighter background.
Texture determination using elastic waves for HCP and cubic materials Bo Lan, T. Ben Britton, Michael J.S. Lowe, Fionn P.E. Dunne Imperial College London, Exhibition Road, London, SW7 2AZ, United Kingdom
Crystallographic texture in polycrystalline HCP and cubic materials,
often developed during thermo-mechanical deformations, has
ABSTRACTS TUESDAY AM - CHARACTERIZATION 47
profound effects on various properties at the macroscopic or
component level. Currently widely-used texture detection
techniques, e.g. EBSD, X-ray or neutron diffraction, all have their
limitations, and a cost-effective, lab-based, non-destructive
technique for three-dimensional bulk texture detection has been
elusive. This talk aims introduce a new technique that achieves this
goal utilising elastic (compressional and shear) waves.
This study is based on the theoretical platform [1] previously
introduced by the authors, which demonstrated that the three-
dimensional wave speed variations in a homogeneous
polycrystalline aggregate could be written as the spherical
convolution between texture and single crystal wave speed surface,
thus enabled inverse texture extractions from polycrystal wave
speed measurements. This talk extends the study by establishing a
lab-based platform using the conventional water-bath ultrasonic
scanning system, for accurate measurements of polycrystal wave
speed variations and hence bulk texture. The technique is capable of
delivering important texture information that informs properties
such as elasticity, thermal expansion, magnetism etc for polycrystals.
However, there are two cases where texture information is not
accessible: (1) the extracted ODF is theoretically limited up to 4th
order truncation to the harmonic expansion of the original function;
(2) in HCP materials, such as Ti and Zr, only the (0001) pole figure is
achievable given the transverse (elastic) isotropy of its single crystal.
A range of industrially important materials have been examined,
including CP Ti, CP Zr, Zircaloy 4 (all pure HCP), Ti-6Al-4V (near alpha
HCP), 304 and 316 (austenitic-FCC), and 430 (ferritic-BCC) stainless
steels. By using the compressional wave results only, one can
recover the pole figures for single-phased materials and the majority
phase in dual-phased material, and estimate the alpha-beta phase
compositions for the latter. These results are calibrated against the
well-established neutron diffraction technique with the
conventional setup using monochromatic beams and Euclidian
cradle, and they agree well with the diffraction results across the
wide spectrum of materials.
We have also extended the convolution theory to shear waves as
well, and the interaction between shear wave and texture unlocks
the possibility of measuring the texture in the second phase in a dual
phase material (e.g. duplex stainless steel, Ti6246) too. We believe
this package of elastic wave development can provide valuable
texture information to a broad range of applications in metal,
mineral and geology studies.
[1] B Lan, MJS Lowe, FPE Dunne, J Mech Phys Solids, 83, 2015 (2 articles).
On-axis Transmission Kikuchi Diffraction in the SEM. Performances and Applications E. Bouzy1,2, E. Brodu1,2, J.-J. Fundenberger1,2 1Laboratoire d’Etude des Microstructures et de Mécanique des Matériaux (LEM3), UMR CNRS 7239, Université de Lorraine, 57045 Metz, France 2Laboratory of Excellence on Design of Alloy Metals for low-MAss Structures (DAMAS), University of Lorraine, 57045 Metz, France
TKD (Transmission Kikuchi Diffraction) is a recent technique [1] of
orientation mapping in the SEM. Via the use of thin electron-
transparent samples, it allows reaching a spatial resolution of the
order of a few nanometers, whereas the resolution of the EBSD
technique on bulk samples is a few tens of nanometers. A new
configuration for the TKD technique has been proposed and
validated at LEM3 [2]. Overall, this new configuration allows
producing orientation maps with an improved spatial resolution and
also in less time in comparison to the initial configuration.
With this new configuration, the detector is set beneath the sample
in a horizontal position instead of being in a vertical position like in
the usual configuration. Also, it is centered in the transmitted beam
direction, which is why this configuration is called on-axis TKD.
Because the electrons which contribute to the formation of the on-
axis diffraction patterns are scattered at low angle, their intensity is
the highest. It allows to acquire orientation maps faster or/and with
a lower electron beam intensity in comparison to usual TKD. It has
been established that an electron dose twenty times lower is
sufficient to obtain diffraction patterns of the same quality. In
addition, it is possible to access a higher lateral resolution by
reducing the electron beam size via a current reduction and by using
very thin samples.
Taking into account the advantages of this technique, there are two
fields of application. The first is the field of the materials with
ultrafine grains or nanometer-sized for which the EBSD technique
fails. The other is the field of electron damage sensitive materials for
which it is necessary to use low dose electron beam. Many examples
taken from these two fields of application will be shown and
analyzed.
[1] R. R. Keller, R. H. Geiss J. of Microscopy (2012) 245, 245-251. [2] J.- J. Fundenberger, E. Bouzy, D. Goran, J. Guyon, H. Yuan, A.
Morawiec (2016) Ultramicroscopy 161, 17–22.
Microtexture and Local Anelasticity Measurements: Uncharted Possibilities K.S. Thool1, A.S. Panwar1, K.V. Manikrishna2, D. Srivastava2 and I. Samajdar1 1Indian Institute of Technology, Mumbai, India. 2Bhabha Atomic Research Centre, Mumbai, India
Dynamic mechanical analysis (DMA) has been used to measure
internal friction and even stipulated [1] to represent residual
stresses. In the past, such measurements were ‘bulk’ in nature. The
advent of nano-dma (dynamic mechanical analysis), and the ability
to estimate local anelasticity at different frequencies, provide
interesting possibilities. Experimental measurements on anelasticity
depend on the crystallographic orientation, defect structure and the
state of residual stress. Experimental nano-dma plus microtexture
measurements, with appropriate molecular dynamics (MD)
simulations, can decouple these factors. The combination may thus
provide a potential (and niche) platform for microstructural study.
This has been the objective. Commercial single-phase zirconium was
subjected to controlled plastic deformation. Relatively minor tensile
strains were shown to enforce significant strain localizations,
especially in terms of near boundary mesoscopic shear strains [2].
Nano-dma was shown to capture the microstructural perturbations,
ABSTRACTS TUESDAY AM - CHARACTERIZATION 48
and more importantly to provide clear possibilities for estimating
developments in local residual stresses.
[1] C. Zener (1937) Phys. Rev., 52, 230. [2] N. Keskar, S. Mukherjee, K.V. Mani Krishna, D. Srivastava, G.K.
Dey, P. Pant, R.D. Doherty, I. Samajdar (2014) Acta Mater., 69, 265.
ABSTRACTS TUESDAY PM1 - PLENARIES 49
TUESDAY PM PLENARY SESSION
Evolving deformation structures: high-resolution reciprocal space mapping and orientation distribution of individual grains W. Pantleon Section of Materials and Surface Engineering, Department of Mechanical Engineering, Technical University of Denmark, Kongens Lyngby, Denmark.
During plastic deformation of polycrystals, grains of initial unique orientation develop an intrinsic orientation spread due to trapping of dislocations
in dislocation boundaries. The deformation structures cause subdivision of individual grains into subgrains and increasing orientation differences
between the latter. A unique method, high-resolution reciprocal space mapping, is presented by which the evolution of subgrain structures can be
monitored in-situ during varying loading conditions with high-energy synchrotron radiation. By mapping a single diffraction peak from an individual
grain in a polycrystals with high resolution three-dimensionally in reciprocal space repeatedly during the deformation process, individual subgrains
can be identified by their unique orientation and followed during deformation; new insights in the development of the deformation structures are
gained from their elastic strains and the developing orientation differences. In this manner, at most an azimuthal projection can be obtained
analyzing a single diffraction peak and only part of the orientation spread within a grain can be resolved. In-situ investigations of the developing
deformation structures are therefore complimented by post-mortem characterization of the deformation structures with electron backscatter
diffraction. The essential information gained from the local orientations, their spatially heterogeneity and the advanced possibilities for
characterizing the micro orientation distribution function of individual grains in deformed microstructures are discussed.
Local Curvature Multi-Vertex Grain Growth Model and Its Application T. Tamaki and K. Ushioda Nippon Steel & Sumitomo Metal Corporation, Chiba, Japan.
Steel is used in many fields such as vehicle, railroad, energy, architecture, machine, and so forth. In recent years the higher performance has been
increasingly required from the points of environmental conservation and security commitment issues. Steel is the polycrystalline material, whose
grain size, grain size distribution and texture have a significant effect on properties of the material. Therefore, it is very important to predict and
control the grain size, grain size distribution and texture in order to produce the high quality material.
In the presentation, focus is placed on the change in microstructure and texture during the normal and abnormal grain growth of metallic
materials. The aim is to elucidate the mechanism of grain growth and texture formation in steel. The following approaches have been performed.
First, the two-dimensional local curvature multi-vertex model, which is the physical and direct model for grain growth, has been proposed. A
simulator has been manufactured based on the proposed model, and the validity of the proposed model has been proved.
Next, in order to investigate the mechanisms on the evolution of microstructure and texture during grain growth of steel sheet, the two-
dimensional local curvature multi-vertex model was applied to the normal grain growth of actual steel sheets for examining the effect of the
respective misorientation dependencies of grain boundary energy and mobility on grain growth in comparison with experimental results. The
simulation result revealed that the grain boundary energy had a major influence on the change in misorientation distribution with grain growth,
whereas the grain boundary mobility did not have such a large influence.
Finally, the meso-scale pinning model for grain boundary migration by one pinning particle has been proposed. This model is the physical model
that minimizes grain boundary energy as an evaluation function. In the presence of pinning particles, the models of normal grain growth and
abnormal grain growth by control of grain boundary energy have been established.
Additionally, the recent industrial application of texture control in various filed is presented in relation to the required performances.
ABSTRACTS TUESDAY PM1 - DEFORMATION 50
Symposium D: Deformation Textures Session: Titanium
Symposium Chairs:
Professor Chadwick Sinclair, Department of Materials Engineering, University of British Columbia
Professor Warren Poole, Department of Materials Engineering, University of British Columbia
Dr. Samantha Daly, Department of Mechanical Engineering, University of California, Santa Barbara
Effect of Texture on Anisotropic Deformation Behaviors in Cold-rolled and Annealed Pure Titanium Nahoko Saji1, Yu Bai1,2, Takahiro Kunimine3, Akinobu Shibata1,2 and Nobuhiro Tsuji1,2
1Department of Materials Science and Engineering, Kyoto University, Kyoto, Japan. 2Elements Strategy Initiative for Structural Materials (ESISM), Kyoto University, Kyoto, Japan. 3School of Mechanical Engineering, Kanazawa University, Kanazawa, Japan.
It is known that cold-rolled and annealed sheets of commercially
pure titanium, having hexagonal close-packed (HCP) crystalline
structure, show anisotropic deformation behaviors depending on to
which direction on the sheet plane the tensile deformation is carried
out. The purpose of the present study is to clarify the reason for the
anisotropic deformation of pure titanium. Cold-rolled and annealed
sheets of commercial purity titanium (JIS grade-1) with a thickness
of 0.5 mm and a mean recrystallized grain size of 28 m were used
as the coarse-grained specimens. The starting coarse-grained
titanium showed the typical recrystallization texture of pure
titanium indexed as {03-37}<2-1-10> where the [0001] c-axis is tilted
by 30-40° from the normal direction (ND) toward the transverse
direction (TD) of the sheet. Ultrafine grained (UFG) specimens with
a recrystallized mean grain size of 1.1 m were also prepared by
processing the starting sheets by the accumulative roll bonding
(ARB) followed by annealing. The UFG specimens also showed a
similar [0001]-tilted texture. The coarse-grained and UFG sheets
were tensile tested at room temperature, and both specimens
having different grain sizes exhibited totally different stress-strain
curves depending on the tensile direction: i.e., the specimens tensile
deformed along the rolling direction (RD) showed typical stress-
strain curves characterized by yielding, strain-hardening and necking
to failure, while the specimens deformed along TD showed higher
yield strength than the RD specimens, early necking and quite large
post-necking elongation. Different crystal rotation behaviors during
the tensile deformation were found depending on the tensile
directions after detailed EBSD analysis. Especially in the TD
deformed specimen, crystal rotation of the main texture resulted in
a crystallographic softening, i.e., an increase of Schmid factor for
prismatic slips. However, it was also clarified that the geometrical
softening is not only the reason for the early necking and large post-
necking elongation apparent on the stress-strain curves of the TD
specimens. Digital image correlation (DIC) analysis of the specimens
confirmed that the necking behaviors were totally different between
the RD and TD specimens, and the TD specimen certainly showed
early necking followed by diffuse necking. The reason of the
anisotropy will be discussed in terms of activation of deformation
twins and different kinds of slips in addition to the texture rotation,
which were all dependent on the tensile direction.
Effect of crystallographic texture on micro-mechanisms of deformation in monotonic and cyclic loading of titanium Subhasis Sinha, Atasi Ghosh, N.P. Gurao Indian Institute of Technology Kanpur, Kanpur-208016, India
Commercially pure hexagonal close packed titanium with less than
ideal c/a ratio was subjected to uniaxial tension and cyclic loading
for one cycle and multiple cycle till failure in stress control and strain
control mode. Samples with distinct initial texture characterized
with basal texture (c-axis along loading direction) and prismatic-
pyramidal texture (c-axis perpendicular to the loading axis) were
tested on a servohydraulic universal testing machine and subjected
to electron back scatter diffraction to study the evolution of
microstructure and micro-texture as a function of monotonic and
cyclic loading. Few select samples were subjected to in situ electron
back scatter diffraction to develop better insight into the operative
micro-mechanisms during monotonic and reverse loading. It was
observed that the sample with basal texture (c-axis along the
loading direction) showed higher yield strength and lower ductility
than the sample with c-axis normal to the loading direction in
monotonic tension. The former was characterized by single variant
extension twin while the latter was characterized by multi variant
extension and contraction twins. Cyclic loading test on the two
samples indicated an interesting trend with the sample with lower
monotonic ductility exhibiting higher cyclic life in strain control low
cycle fatigue but lower cyclic life in stress control test. Similar trend
was observed for the sample that exhibited higher monotonic
ductility and cyclic ductility in stress control mode but low cyclic
ductility in strain control mode. The cyclic samples showed
characteristics twins similar to that in tension albeit extremely thin
in load reversal (one cycle) and with moderate thickness in cyclic
samples loaded till failure. It is proposed that the nucleation,
propagation and lateral thickening of twins play an important role in
determining the monotonic and cyclic ductility of titanium.
Orientation with single variant twinning in monotonic tension and
stress control cyclic testing promotes lateral thickening of twins that
contributes to lower ductility while twin nucleation and propagation
contribute to strain hardening and facilitate detwinning in load
reversal contributing to higher monotonic and cyclic ductility
respectively. Elastoplastic self-consistent simulations were carried
out to quantify the operation of different slip and twin modes to
rationalize the experimental results.
ABSTRACTS TUESDAY PM1 - DEFORMATION 51
Microstructural Evolution of Ti-7Al Under Cyclic Loading R.E. Lim1, Y. Shen1, T. Ozturk1, C.A. Kantzos1, J.V. Bernier2, P.A. Shade3, R.M. Suter1 and A.D. Rollett1 1Carnegie Mellon University, Pittsburgh, USA. 2Lawrence Livermore National Laboratory, Livermore, USA. 3U.S. Air Force Research Laboratory, Dayton, USA.
High-energy x-ray energy diffraction microscopy (HEDM), which is a
synchrotron-based, non-destructive, 3-D characterization technique,
was used to track three-dimensional microstructural evolution in a
sample of -phase Ti-7Al under variable tensile load. Near-field
HEDM measures orientation on a 3-D grid which provides grain
morphology, while far-field HEDM measures the strain state of each
individual grain. Combined with digital image correlation (DIC) and
synchrotron-based x-ray micro-tomography (-XCT), we perform
grain-by-grain analysis to track strain evolution under cyclic loading.
The results show a decrease in residual elastic strain over the first
couple of cycles followed by an increasing build-up of strain. This will
be used in the future to model fatigue at the microstructural level
using full field micro-mechanical models.
About the combined role of texture and grain size on hardening behavior of cp titanium sheets F. Wagner1,2, T. Richeton1,2, C. Chen2 and L.S. Toth1,2 1LEM3 (UMR-CNRS 7239), Université de Lorraine, Ile du Saulcy, 57045 Metz-Cedex1, France. 2Laboratory of Excellence on Design of Alloy Metals for low-mAss Structures (Labex Damas), Université de Lorraine, 57045 Metz-Cedex1, France
Titanium sheets of commercial purity were cold rolled up to 75% and submitted to various heat treatments. These treatments generated microstructures with different grain sizes. In few cases partially recrystallized states were also considered. Mechanical properties were determined from tensile tests. It appeared clearly that the grain size is an important characteristic for both the level of the yield stress and the amplitude of the hardening whereas the texture governs the anisotropy as evidenced from tractions along RD and TD. Post-mortem observations (i.e. after extension) showed a very limited twinning activity, the plastic deformation resulting mainly from the slips over the various slip systems according to the orientation of the grains as determined, before the tensile tests, from EBSD maps. To better explain the grain size effect, an elasto-viscoplastic self-consistent model based on the translated field method [1] was modified to incorporate grain size effects. These effects were taken into account in a phenomenological way by adding a grain size dependent contribution in the expression of the critical resolved shear stresses (CRSS). The various performed simulations permit to draw the following conclusions:
• the yield stress is strongly linked to the CRSS of the easiest slip system (prismatic slip system) and the grain size
• the anisotropy (RD and TD extension) results from the initial texture and the ratios of the CRSS of the different slip systems
• the hardening amplitude decreases with decreasing grain size because of the role of the grain boundaries acting as dislocation traps.
[1 K.E.K. Amouzou, T. Richeton, A. Roth, M.A. Lebyodkin, T.A. Lebedkina (2016), IJP, Vol. 80, p.222-240
ABSTRACTS TUESDAY PM1 – RUDY WENK 52
Symposium W: A Celebration of the Contributions of Rudy Wenk Symposium Chairs:
Dr. Lowell Miyagi, Geology & Geophysics, University of Utah
Dr. Pamela C. Burnley, Department of Geoscience, University of Nevada, Las Vegas
Dr. Sven Vogel, Los Alamos National Laboratory
20 Years of Maud and the Rietveld Texture Analysis L. Lutterotti1, S. Matthies2 and H. -R. Wenk3 1Department of Industrial Engineering, University of Trento, Trento, Italy. 2Muller-Berset-Str. 3, 01309 Dresden, Germany. Department of Earth and Planetary Science, University of California at Berkeley, Berkeley, CA.
Traditionally the orientation distribution of a textured polycrystalline
material has been obtained from a limited number of more or less
complete pole figures. The method is practical for metals and alloys
or compounds with highly symmetrical space groups and few
diffraction reflections, but not for low symmetry geological materials
or composites where the high overlap makes it difficult to measure a
sufficient number of clean pole figures. The Rietveld texture analysis
(RTA) has been developed from a team lead by Rudy Wenk to
overcome such difficulties from the beginning of the nineties of last
century. After some years of developments and the first successful
trials on standard samples, he was again Prof. Wenk who advocates
for the necessity of writing a RTA tool by which everyone in the
scientific community could use the new method. The first version of
such tool, MAUD (Materials Analysis Using Diffraction), came out in
1997 [1]. Thanks to the constant work, testing and push of Rudy
Wenk the program and the RTA method has been matured to the
actual package in use by several laboratories around the world. It is
worth nothing now that there shouldn’t be a MAUD program
without Prof. Wenk. He has been always also the principal supporter
and tester, using it himself, proposing and supporting new
developments and pushing others to use it and the RTA. He has now
used it to obtain quantitative texture and microstructural
information of very complex geological materials like shales
containing up to 7 phases [2]. Not only, he has showed how to
measure texture using transmission images and the RTA [3] and
recently doing the same for high pressure experiments [4]. His
works, from instrumentation to methodology, analysis applications
and education, has permitted the RTA to develop and diffuse in the
scientific world and not remain a pure theoretical exercise.
[1] L. Lutterotti, S. Matthies, H. -R. Wenk, A. S. Schultz and J. W. Richardson, Jr. (1997) J. Appl. Phys. 81, 594.
[2] W. Kanitpanyacharoen, H. -R. Wenk, F. Kets, C. Lehr and R. Wirth (2011) Geophysical Prospecting 59, 536.
[3] H. -R. Wenk and S. Grigull (2003) J. Appl. Cryst. 36, 1040. [4] H. -R. Wenk, I. Lonardelli, J. Pehl, J. Devine, V. Prakapenka, G.
Shen, H.-K. Mao (2004) Earth and Planetary Science Letters 226, 507.
Texture Measurements by Neutron Time-of-flight Diffraction – a Powerful Tool Pioneered by Rudy Wenk S.C. Vogel1, E. Aydogan1, S. Takajo1,2, Y. Onuki3, T. Tomida4, L. Lutterotti5, and H.R. Wenk6 1Los Alamos National Laboratory, Los Alamos, NM, U.S.A. 2JFE Steel Corporation, Kurashiki, Japan. 3Frontier Research Center for Applied
Atomic Sciences, Ibaraki University, Ibaraki, Japan. 4Ibaraki Prefectural Government, Ibaraki, Japan. 5Department of Industrial Engineering, University of Trento, Italy. 6UC Berkeley, Berkeley, CA, U.S.A.
Neutron time-of-flight diffraction has become a routine tool for bulk
texture characterization with dedicated instruments at all pulsed
neutron sources. The first neutron time-of-flight diffractometer
specifically optimized for texture measurements was HIPPO at
LANSCE, with Rudy Wenk being Co-PI with Bob Von Dreele and
Kristin Bennett [1,2]. Commissioned in 2001, the instrument has
since been a work-horse for texture measurements for one and half
decades. In this contribution, we present the principles of neutron-
time-of-flight texture measurements and review some highlights of
the research conducted by Rudy Wenk. We propose an experimental
approach to measure the resolution in ODF space of a given
instrument. Finally, we report on a second texture round robin,
following Rudy Wenk's initial round robin on neutron texture
measurements [3]. The idea for this round robin originated from the
availability of full-pattern Rietveld refinements that allow to
combine texture analysis with crystal structure determination as
well as microstructure characterization, e.g. volume fractions of
ferrite and austenite in steels. We hope to be able to present first
results at the conference.
[1] K. Bennett, R. B. Von Dreele, & H. R. Wenk (1999) "HIPPO." a new high intensity neutron diffractometer for characterization of bulk materials, in “Proc. ICOTOM-12”, JA Szpunar, Ed. NRC Research Press, Ottawa, Canada, 129-134.
[2] K. Bennett, R. B. Von Dreele, & H. R. Wenk (1999) "‘HIPPO'-A New High Intensity Neutron Diffractometer for Bulk Analysis of Materials." IUCr Newsletter 22, 6.
[3] H.-R. Wenk (1991) "Standard project for pole-figure determination by neutron diffraction." Journal of Applied Crystallography 24, 920-927.
ABSTRACTS TUESDAY PM1 – RUDY WENK 53
Principles of ice dynamics during crystal-plastic deformation: Linking texture, rheology and average grain size S. Piazolo1,2,, D. Cyprych1, C.L. Wilson3, Vladimir Luzin4, Mark Peternell 5 1 Australian Research Council Centre of Excellence for Core to Crust Fluid Systems/GEMOC, Department of Earth and Planetary Sciences, Macquarie University, NSW 2109, Australia. 2School of Earth and Environment, University of Leeds, UK. 3School of Geosciences, Monash University, Clayton, Victoria, 3800, Australia. 4ANSTO Locked Bag 2001, Kirrawee DC, Lucas Heights, NSW 2232, Australia. 5Department of Earth Sciences, University of Mainz, 55099 Mainz, Germany.
Prediction of glacier and polar ice sheet dynamics is a major
challenge, especially in view of changing climate. The flow behaviour
of an ice mass is fundamentally linked to processes at the grain and
subgrain scale. However, our understanding of ice rheology and
microstructure evolution based on conventional deformation
experiments, where samples are analysed before and after
deformation, remains incomplete. To close this gap, we combine
deformation experiments with in-situ neutron diffraction to monitor
continuously the evolution of texture, average grain size and
rheology.
We prepared ice samples from deuterium water, as hydrogen in
water ice has a high incoherent neutron scattering rendering it
unsuitable for neutron diffraction analysis. In experiments we
deform initially randomly oriented polycrystalline ice at three
different temperatures and two different strain rates. Textural
development shows a general change from a weak single central c-
axis maximum to a strong girdle distribution at 35° to the
compression axis. Dislocation-related hardening accompanies this
switch and is followed by weakening due to new grain nucleation
and grain boundary migration. With decreasing strain rate and
increasing temperature, grain boundary migration becomes
increasingly dominant and texture more pronounced. This goes
hand in hand with different stress-strain behaviour in particular
systematic differences in peak and steady-state stress values.
Our observations highlight the links between dynamics of
competition of deformation-related processes, texture development
and rheological behaviour. This link needs to be taken into account
to improve ice mass deformation modelling critical for the
prediction of climate change consequences. Our results show that
neutron diffraction textural and grain size analysis combined with in-
situ experiments represents a powerful tool to investigate the
dynamics of ice.
Microscopic study of texture evolution under tensile strain: slip events in zirconium resolved in 3D R. Chen,1 W. Chen,1 J. Lind,2 A. D. Rollett,1 and R. M. Suter1 1Carnegie Mellon University, Pittsburgh, PA USA. 2Lawrence Livermore National Laboratory, Livermore, CA USA.
Non-destructive, three dimensionally resolved measurements of
lattice orientation are used to image rotations associated with slip
events during plastic deformation of a zirconium polycrystal. Near-
field High Energy X-ray Diffraction Microscopy has been used to
perform the measurements during tensile deformation up to 17%
true strain. The measurements were carried out at the 1-ID
beamline at the Advanced Photon Source. In lower symmetry
materials such as hexagonal close-packed zirconium, it is
straightforward to link intra-granular rotations to single slip systems
by characterizing the variations in rotation axis and angle
corresponding to individual events. We perform voxel-by-voxel
searches for appropriate orientation discontinuities within grains. In
prior work we characterized twin formation; here, we extract
prismatic slip events which are favored by the anisotropic texture of
the sample. Similar searches for basal events yielded no events. The
lattice orientation discontinuities are observed to form low angle
interfaces within what were previously highly ordered crystalline
grains. The degree to which these rotations occur on expected
crystallographic planes and the variations in rotation angle and axes
within these planes can be characterized. The results of this analysis
are compared to 3D FFT based visco-plastic simulations that use the
initial measured microstructure as input. Initial correlation of the
computed lattice rotations with the observed lattice rotations is
encouraging.
ABSTRACTS TUESDAY PM1 - RECRYSTALLIZATION 54
Symposium R: Crystallization, recrystallization and growth textures Symposium Chairs:
Dr. Rodney McCabe, Los Alamos National Laboratory
Asher Leff, Department of Materials Science and Engineering, Drexel University
Preferred orientation formation in Al-3mass%Mg subjected to shear deformation and subsequent annealing Y. Takayama, T. Kanamaru, K. Wachi and H. Watanabe Utsunomiya University, Utsunomiya, Japan,
Shear deformation is imposed on materials by several advanced
techniques for microstructural and textural control. Shear texture
evolved during deformation tends to remain after subsequent
annealing. Preferred orientation formation with shear deformation
and annealing in Al-3mass%Mg alloy rolled sheet has been
investigated by SEM/EBSD technique. S-shaped specimen was
prepared from the alloy sheet to impose shear strain in
compression. The central objective part of the S-shaped specimen
was sheared with rotation about the normal axis so as to develop
preferred orientations of {111} parallel to the original shear plane
and <110> parallel to the original shear direction before
deformation. In-situ EBSD analysis revealed that the preferred
orientations formed by shear deformation remain and evolve as
recrystallization texture during subsequent annealing. The evolution
of the shear recrystallization texture depended obviously upon
sample direction parallel to shear direction.
Microstructure and Texture Evolution in Pulsed Electrodeposited Nanotwinned Copper Rohit T. Mathew and M.J.N.V. Prasad
Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Powai, Mumbai-400 076, INDIA.
Highly textured nanotwinned copper foils were fabricated using
pulsed electrodeposition from an additive-free acidic copper
sulphate bath. The evolution of grain structure and crystallographic
texture of electrodeposited nanotwinned copper is investigated as a
function of electrodeposition parameters such as substrate material,
duty cycle and peak current density. The use of pure Ti (HCP), IF
steel (BCC), SS304 (FCC) or nanocrystalline Ni-P alloy (FCC) as
cathode during electrodeposition led to formation of differently
oriented nano-twins and varying density of growth-twins in Cu foils
with dominant {111}, {100} or {110} type fiber texture. A similar
trend in change of crystallographic texture was also observed in Cu
foils deposited at different pulse duty cycles at constant peak
current density. Electrodeposition of copper on Ti substrate showed
a strengthening of {111} fiber texture with increasing peak current
density. This texture change was also accompanied with grain
refinement and occurrence of columnar grain structure containing
high density of nanotwins of uniform twin lamella thickness of ~50
nm parallel to the substrate surface. These microstructural
developments are correlated with the stability of growing planes,
interfacial energies and preferred diffusion directions in FCC
materials. Nanoindentation and tensile deformation studies showed
that the mechanical behavior of the as-deposited Cu foils is affected
significantly due to their different microstructures and texture.
Characteristics of Thin Cu Films Electrodeposited on Textured Ni Co Substrates B. Panda1 and R. K. Ray2 1CMR Institute of Technology, Bangalore, India. 2MN Dastur School of Materials Science and Engineering, IIEST Kolkata,India
An attempt has been made to study the effects of current density
and the texture of the underlying substrate on electrodeposited
copper. For this purpose, five Ni-Co alloys, Ni-10 Co, Ni-20 Co, Ni-30
Co, Ni-40 Co and Ni-60 Co, in the cold rolled as well as in the
annealed conditions, were used as substrates. Acid copper sulfate
solution was used to deposit thin Cu layers on the substrates, using a
Cu plate as anode, at four different current densities, 1, 10, 30 and
50 mA/cm2
The thickness of the electrodeposited Cu layer increased nearly
linearly with current density, but was independent of the texture
and composition of the underlying substrate. In general, the X-ray
diffraction line intensities for the deposited Cu layer sharpened and
those for the substrate Ni alloys weakened with increase in current
density. The textural developments in the Cu deposits appeared to
be quite independent of the textures as well as the compositions of
the substrate materials. The deposited Cu layers did not inherit the
textures of the substrates at the lower current densities, and also
developed their own textures at higher current densities. The Cu
(220) peak ultimately became the strongest XRD peak for the
electrodeposited layer. The grain sizes of the deposited Cu layers
decreased with increasing current density, quite independent of the
substrate texture. The surface roughness of the deposited layers was
distinctly smoother for the annealed substrates, as compared to the
cold rolled Ni-Co alloys.
Fabricating Designed Crystallographic Textures through Heterogeneous Templated Grain Growth D.J. Frandsen, O.K. Johnson Brigham Young University, Provo, United States
Microstructure sensitive design (MSD) is a theoretical framework
that permits the identification of microstructures with optimized
engineering performance. However, fabrication of these designed
microstructures is limited by current manufacturing methods. In this
talk, we describe a new materials processing route called
Heterogeneous Templated Grain Growth (HTGG), which may assist
in bridging the gap between simulation and fabrication of designed
crystallographic textures.
ABSTRACTS TUESDAY PM1 - ENGINEERING 55
Symposium A: Texture and Anisotropy in Advanced Engineering Processes and Materials Session: Advanced Materials
Symposium Chairs:
Professor Tracy Nelson, Department of Mechanical Engineering, Brigham Young University
Dr. Ashley Spear, Department of Mechanical Engineering, University of Utah
Influence of equal channel angular pressing temperature on texture in pre-extruded AX41 magnesium alloy
M. Janeček1, T. Krajňák1,2, P. Minárik1, J. Stráská1, J. Gubicza3, K.
Máthis1 and R. Kužel1 1Charles University in Prague, Prague, Czech Republic. 2Slovak Academy of Sciences, Bratislava, Slovakia. 3Eötvös Loránd University, Budapest, Hungary.
Pre-extruded AX41 magnesium alloy was severely deformed by
equal channel angular pressing up to 8 passes at temperatures of
220 °C and 250 °C. The influence of temperature of processing on
the crystallographic texture was investigated by means of electron
backscatter diffraction (EBSD) and X-ray diffraction. The original
fiber texture formed after extrusion is gradually transformed into
two strong texture components with increasing number of ECAP
passes. The intensity of these components was found to be affected
by the temperature of processing. Based on the post-mortem
analysis of Burgers vector population, a model describing the texture
evolution during ECAP processing was proposed.
Texture development in soft ferromagnetic Fe-Co-2V processed by Equal Channel Angular Extrusion (ECAE) J.R. Michael1, A.B. Kustas1, D.F. Susan1, I. Karaman2 and T. Jozaghi2
1Sandia National Laboratories, Albuquerque, NM, USA. 2Texas A&M University, College Station, TX, USA.
The 48Fe-48Co-2V alloy, also known as Hiperco® 50A, is a soft
ferromagnetic material used in electric motor and solenoid
applications. While this alloy has remarkably high permeability and
the highest saturation induction of all soft magnetic alloys, the poor
mechanical properties and workability are problematic. Recently,
equal channel angular extrusion (ECAE) was used to process
Hiperco® and improve these properties. However, the effects of the
ECAE processing on the corresponding crystallographic textures,
important to magnetic properties, have yet to be considered. In this
study, textures in Hiperco® following ECAE are characterized.
Textures are obtained from specimens processed via routes C and E
at high deformation temperatures (T = 750 – 850 °C). Route C is
shown to develop a classical shear texture, defined by partial {110}
and <111> fibers, while route E developed a strong <111>
orientation in the extrusion direction. These textures are discussed
in relation to the differences in the processing route and compared
to those of commercial Hiperco® bar and sheet material. Potential
implications of the ECAE textures on the structure-sensitive
magnetic properties are also discussed.
® Hiperco is a tradename of Carpenter Technology Corp., Reading, PA
Sandia is a multi-mission laboratory operated by Sandia Corporation,
a Lockheed Martin Company, for the United States Department of
Energy’s National Nuclear Security Administration under contract
DE-AC04-94AL85000.
Texture evolution in extruded AX41 magnesium alloy severely deformed by equal channel angular pressing via routes A, Bc and C T. Krajňák1,2, P. Minárik1, J. Gubicza3, K. Máthis1, R. Kužel1 and M. Janeček1 1Charles University in Prague, Prague, Czech Republic. 2Slovak Academy of Sciences, Bratislava, Slovakia. 3Eötvös Loránd University, Budapest, Hungary.
The influence of three different equal channel angular pressing
(ECAP) routes (A, Bc and C) on the crystallographic texture
development in the pre-extruded AX41 magnesium alloy was
investigated using electron backscatter diffraction (EBSD). The
microtexture evaluated from EBSD was correlated with the
macroscopic crystallographic texture determined by X-ray
diffraction. The texture of ECAP processed samples was found to be
significantly influenced by the processing route. In all samples, two
main texture components were formed. However, their intensities
vary for the different ECAP routes. X-ray line profile analysis was
employed to examine the distribution of dislocations in the
particular slip systems. Moreover, a model describing the texture
evolution during ECAP processing taken into account different
activation of the basal and the second order pyramidal slip systems
was proposed.
The nucleation of cube grains during primary recrystallization of aluminium M.M. Miszczyk, H. Paul Polish Academy of Sciences, Institute of Metallurgy and Materials Science, Krakow, Poland
The influences of microstructure and texture on the cube grain
formation during early stages of recrystallization of a commercial
AA1050 alloy and pure Al single crystal of S{123}<634> orientation
have been characterized. Samples of AA1050 alloy were deformed
along two deformation modes to form different as-deformed
texture components and then lightly annealed: one group was plane
strain compressed (PSC) in a channel-die, whereas the second group
was deformed by equal channel angular extrusion (ECAE). The
results obtained on polycrystalline AA1050 alloy were compared
with recrystallization behavior of PSC single crystals of different
variants of S orientation which is stable up to 40% of PSC. The
textures were measured by X-ray diffraction and SEM/EBSD. After
both deformation modes a very weak residual cube texture
component was observed in the samples of AA1050 alloy. Cube-
oriented grains were not formed during annealing of the ECAE
samples whose main as-deformed texture components were close
to {124}<651>. During recrystallization these transformed to two
components of ~{100}<011> and ~{221}<114>-type essentially by
ABSTRACTS TUESDAY PM1 - ENGINEERING 56
<110> rotations. Cube grains were extensively formed during
annealing of PSC of S-oriented single crystals and AA1050 alloy
samples. In polycrystalline samples they were situated preferentially
inside or in between the S-oriented deformed areas with local
disorientations about <111> axes.
ABSTRACTS TUESDAY PM1 - CHARACTERIZATION 57
Symposium C: Texture and Microstructure Characterization Symposium Chairs:
Dr. Irene Beyerlein, Department of Mechanical Engineering, University of California, Santa Barbara
Dr. Mukul Kumar, Lawrence Livermore National Laboratory
The contribution of EBSD to texture studies over the past 30 years David J Dingley University of Bristol, Bristol UK
It is thirty years since the first paper describing the collection and
presentation of orientation data using the Electron Backscattering
technique was presented at an ICOTOM meeting. Other emerging
techniques presented at that meeting were automated transmission
electron microscopy, synchrotron x-ray radiation, neutron
diffraction and an energy dispersive x-ray detector system. Over the
following decade use of the EBSD technique expanded rapidly
though many of the papers were more concerned with proving the
reliability of the technique by comparison with x-ray diffraction
results than with exploring the fundamental advantage of the
technique. Its greatest advantage over all others is that it provides
both macroscopic texture and microscopic texture presented in the
form of orientation maps. Less obvious was the fact that EBSD
removed at a stroke the uncertainties, the so called ghost problem,
when calculating the orientation distribution function from
individual pole figure data as obtained from x-ray Laue patterns.
Because it enabled the construction of misorientation maps the
emphasis switched to studies of the role of grain boundaries in
texture determination which in turn led to boundary plane
determination and the emergence of serial sectioning and 3D
mapping. Misorientation measurements between neighbouring
points within grains provided a first glimpse of residual deformation
and internal dislocation structures. By 2005, nearly twenty years
after the first paper, texture measurements using EBSD was the
norm and the applications widespread. At the same time
techniques for quantitative strain measurements were becoming
viable and by 2006 the first paper describing a viable method was
published under the title High Resolution EBSD. Just as in the early
years of EBSD the first HR EBSD studies concentrated on proving its
robustness with consequent improvements in data acquisition and
analytical techniques following on. And, as was the case with
standard EBSD, the impact of this technique in advancing our
understanding of texture development and identifying the critical
factors within the deformation structure that control and define the
state of the material, are slowly becoming clearer.
Denoising of EBSD Data R. Hielscher1, C. Silbermann1 and E. Schmidl1 TU Chemnitz, Germany.
Individual orientation measurements in EBSD maps are often
affected by measurement errors. These measurement errors are
especially troublesome if local orientation changes are investigated,
e.g. by means of kernel average misorientation (KAM) or
geometrically necessary dislocation density (GND). The accuracy of
individual orientations measurements can be improved by either
applying better indexing algorithms, e.g., cross-correlation methods,
or by applying denoising techniques.
In our talk we first investigate the impact of the noise level to the
computed KAM and GND values. Next, we compare well known
denoising algorithms, like mean and median filters, with newly
developed methods based on spline approximation and half
quadratic optimization. The new denoising methods are proven to
dramatically increase the accuracy of the determined KAM and GND
values.
Microstructural investigations of materials after severe plastic deformation by means of orientations mapping in TEM and SEM M. Bieda1, A. Jarzębska1, P.Koprowski1,2, J.Kawałko1, K. Kudłacz1, S. Boczkal2, M. Faryna1, K. Sztwiertnia1
1Instititute of Metallurgy and Materials Science Polish Academy of Sciences, Krakow, Poland. 2Institute of Non-Ferrous Metals, Light Metals Division, Skawina, Poland.
Qualitative and quantitative microstructure description of crystalline
materials are crucial for characterization and better understanding of
the mechanisms of deformation and recrystallization processes. In
presented study advanced scanning and transmission electron
microscope methods like t-EBSD, in -situ annealing and orientation
mapping in TEM [1,2] were tested to investigations of materials after
plastic deformations by means of KoBo (extrusion with rotating die)
[3] and hydrostatic extrusion (HE) methods. Statistical analysis of local
orientation, texture and grain boundary characterization were done
for chosen materials of different symmetry like cubic aluminum and
hexagonal zinc and titanium with high resolution capability down to a
few square nanometers. It was proved that those methods can be
successfully applied for complementary analysis to conventional
SEM/EBSD method.
[1] M. Bieda (2012) Sol. St. Phen. 186, 53 [2] www.crystorient.com [3] A. Korbel, W. Bochniak, US Patent No 737, 959 (1998),
European Patent No 0711210 (2000)
EBSD analysis of IF steels: comparison between 2D and 3D statistics S. Ghodrat1, M. Azimi2, 3, E. Lopez2, H. Pirgazi2 and L.A.I. Kestens1, 2 1 Delft University of Technology, Materials Science and Engineering Department, Mekelweg 2, 2628CD Delft, The Netherlands. 2 Ghent University, Department of Materials Science and Engineering, Technologiepark 903, 9052 Zwijnaarde-Gent, Belgium. 3 Isfahan University of Technology, Isfahan, Iran.
Most of the microstructural features in 2D can be characterized
using standard microscopy instrumentation and stereological
procedures; though, there are still many important microstructural
features such as grain boundary inclination or spatial anisotropy of
grain shape, that can only be measured in 3D. Statistical
ABSTRACTS TUESDAY PM1 - CHARACTERIZATION 58
stereological techniques have been developed to gain insight in the
three-dimensional aspects of the microstructure from the 2D data.
To this purpose a commercially cold rolled and annealed IF steel was
examined. By carrying out wide-field 2D and 3D EBSD
characterization, covering an area of 0.42 mm2 and 0.0336 mm3,
respectively, a reference data set was gathered, which provides an
ideal basis for carrying out a statistical analysis This work is of
relevance for constructing virtual representative volume elements
(RVEs) to be employed in microstructurally based FE simulations of
forming operations. The potential will be investigated whether
reliable 3D RVEs can be constructed from 2D conventional EBSD
scans.
ABSTRACTS TUESDAY PM2 - DEFORMATION 59
Symposium D: Deformation Textures Session: Steels - Formability
Symposium Chairs:
Professor Chadwick Sinclair, Department of Materials Engineering, University of British Columbia
Professor Warren Poole, Department of Materials Engineering, University of British Columbia
Dr. Samantha Daly, Department of Mechanical Engineering, University of California, Santa Barbara
Effect of Texture on Mechanically Induced Martensitic Transformation in Duplex Stainless Steel J.-Y. Kang1, H. Kim1, K.-I. Kim2, C.-H. Lee1, H.N. Han2, K.-H. Oh2 and T.-H. Lee1 1Korea Institute of Materials Science, Changwon, Republic of Korea. 2Department of Materials Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul, Republic of Korea.
The effect of austenitic texture on the tensile behavior of a lean
duplex stainless steel was investigated. The texture and grain size
were varied by different history of thermomechanical process while
the phase fraction could be effectively fixed. The shape of tensile
flow curve was primarily affected by austenitic texture while average
grain diameter contributed to the increase in flow stress. The effect
of austenitic texture was attributed to its influence on the
mechanically induced martensitic transformation. In this study,
nearly random austenitic texture exhibited delayed transformation,
consequently resulted in prolonged strain hardening and elongation
than a moderate texture centered at D: {4 4 11}<11 11 8>
component. Dependence of mechanical driving force to
transformation on the austenitic orientation and texture was
analyzed using a simple transformation and crystal plasticity model.
Although D component was supposed to have the smallest
transformation interaction strain along the tensile direction, it
showed the largest stress evolution along that direction. It was
considered that the latter effect overrode the former and resulted in
the observed dependency of the martensitic transformation on the
austenitic texture.
Role of microstructure, texture, and load partitioning in formability of TRIP steel and duplex stainless steel Peijun Hou1, Yuan Li1, Dongchul Chae2, Yang Ren3, Ke An4, and Hahn Choo1
1Materials Science and Engineering, University of Tennessee, Knoxville, TN, 37996, USA. 2Stainless Steel Research Group, POSCO Technical Research Laboratory, Korea. 3X-ray Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA. 4Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
In recent formability studies, a metastable transformation-induced
plasticity (TRIP) stainless steel (SS) exhibited poor resistance to the
delayed cracking phenomenon in deep-drawn cups despite its higher
work hardening rate and ductility compared to a stable austenitic
stainless steel counterpart. In an effort to mitigate this cracking
problem, while keeping the alloy cost down (e.g., lower Ni content),
a duplex SS alloy was developed that indeed demonstrates much
improved resistance to the cracking behavior. However, the duplex
SS shows earing phenomenon instead of cracking in the deep drawn
cups that also needs to be addressed.
The main objective of this present work is to study the constitutive
behavior of the three alloy plates, namely, stable austenite,
metastable austenite (TRIP), and metastable duplex SS alloys. The
goal is to gain basic understanding on the complex relationships
among (1) the alloy composition, (2) constituent phases and their
morphology, (3) macroscopic tensile behavior and anisotropy in
terms of Lankford coefficient, and (4) mesoscopic tensile behavior in
terms of load partitioning, martensitic transformation kinetics, and
texture evolutions.
First, macroscopic tensile behaviors were examined along three
different orientations with respect to the rolling direction of the
alloy plates at ambient temperature to study plastic anisotropy
including the Lankford coefficients. Second, texture and phase
evolutions as a function of applied strain were measured using
synchrotron x-ray diffraction and the results are correlated to the
Lankford coefficient to study the effect of texture and phase
distribution on planar anisotropy. Moreover, the lattice and phase
strain evolutions during uniaxial loading were measured in situ using
neutron diffraction to investigate the effect of strain-induced
martensitic phase (in TRIP SS) and ferritic phase (in duplex SS) on
loading partitioning in comparison to the stable austenitic SS.
This study will provide basic understanding of the alloy behavior for
our concurrent investigation on delayed cracking and earing
phenomena in deep-drawn SS cups.
DAMASK: the Düsseldorf Advanced MAterial Simulation Kit for studying interlinked texture and crystal plasticity phenomena in high strength steels F. Roters, M. Diehl, S.L. Wong, P. Shantraj, D. Raabe Max-Planck-Institut für Eisenforschung, Düsseldorf, Germany.
Here we present DAMASK as a unified freeware texture and crystal
plasticity simulation package. The solution of continuum mechanical
boundary value problems requires a constitutive response that
connects deformation and stress at each material point. In DAMASK
such connection is treated as a hierarchy of three separate items: At
the top-most level, partitioning of the mean boundary values of the
material point among its microstructural constituents and the
associated homogenization of their response is mapped in cases
where there is more than one constituent phase present in the
material. Second, based on an elastoplastic decomposition of finite
strain deformation, these responses follow from time integration of
the plastic deformation rate per constituent. Third, to establish the
latter, a state variable-based constitutive law needs to be
interrogated and its state updated. The Düsseldorf Advanced
MAterial Simulation Kit (DAMASK) reflects this hierarchy as it is
designed in a strictly modular way. This modular structure makes it
straightforward to add additional constitutive models, diffusional
ABSTRACTS TUESDAY PM2 - DEFORMATION 60
and transformation laws as well as homogenization schemes.
Moreover, it interfaces with a number of FE solvers as well as a
spectral solver using an FFT. We demonstrate the features of
DAMASK and apply it exemplarily to several microstructure and
texture related case studies pertaining to the fields of TRIP, TWIP
and dual phase steels.
ABSTRACTS TUESDAY PM2 – RUDY WENK 61
Symposium W: A Celebration of the Contributions of Rudy Wenk Symposium Chairs:
Dr. Lowell Miyagi, Geology & Geophysics, University of Utah
Dr. Pamela C. Burnley, Department of Geoscience, University of Nevada, Las Vegas
Dr. Sven Vogel, Los Alamos National Laboratory
Authigenic Mineral Textures in Basaltic Tuff, Surtsey Volcano, Iceland M.D. Jackson1, S. Couper1, N. Tamura2, C.V. Stan2, and L.M. Miyagi1 1University of Utah, Salt Lake City, USA. 2Lawrence Berkeley National Laboratory, Advanced Light Source, Berkeley, USA.
Hydrothermal alteration of basaltic tephra at Surtsey volcano,
erupted during 1963–1967 in the offshore segment of the
southeastern Icelandic rift zone, produces authigenic mineral
textures with preferred orientations in basaltic glass lapilli and
olivine crystal fragments. The microstructures occur in palagonitized
tuff from surficial outcrops and core extracted from a 181 m hole
drilled in 19791. Synchrotron-based microdiffraction and
microfluorescence maps acquired at LBNL Advanced Light Source
beamline 12.3.2 illustrate how dynamic chemical environments in
these microstructures influence rates of reaction as a function of
temperature, glass or crystal composition, exposed surface area of
the solids, and the volume and changing composition of the leaching
solution. The experiments use a monochromatic X-ray beam of 8–10
KeV focused to a 2 by 5 µm2 spot size on a 0.3 mm thick tuff slice
loaded in transmission into the beam, with the detector inclined at
30°–39°. A Pilatus 1M area detector placed at 150 mm records
Debye rings diffracted by crystalline phases. The resulting diffraction
patterns reveal multiple crystallization episodes of zeolite and Al-
tobermorite, a rare, layered calcium-silicate-hydrate mineral with 11
Å interlayer spacing, in association with diverse authigenic clay
mineral textures. In a palagonitized basaltic lapillus at 137.9 m
depth, 85°C in 1980, for example, a transect across leached glass
into an internal vesicle shows early phillipsite associated with
nanocrystalline clay mineral with 14.2–14.8 Å interlayer spacing;
acicular 11.35 Å Al-tobermorite ([Ca4(Si5.5Al0.5 O17H2)]
Ca0.2·Na0.1·4H2O) that precipitated from highly alkaline leachate
fluids with [002] interlayer spacing oriented radially to vesicle walls;
and subsequent analcite replacing Al-tobermorite. Nanocrystalline
clay mineral in the altered glass has d-spacings similar to nontronite,
either with random c-axis (001) orientations or with preferred
orientations that rotate from 0°–180° over 25–50 µm transects.
These define tubular microchannels produced, perhaps, by early
biogenic activity. In the rim of an altered olivine crystal at 102.6 m
depth, 141°C in 1980, for example, the clay mineral structure wraps
around the tubules in successive 5–10 nm thick layers, shown by
microdiffraction and S/TEM analyses; the (001) d-spacing decreases
from 14.5 Å to 14.2 Å in the external layers. Al-tobermorite with
11.33 Å interlayer spacing occurs at the periphery of these
microstructures. Fifteen years after eruption, the authigenic Al-
tobermorite–zeolite–nanocrystalline clay mineral textures record
abiotic processes produced by reactive rock–water interactions as
well as potentially biogenic processes, perhaps associated with early
infiltration of seawater into the tephra deposits.
[1] S.K. Jakobsson and J.G. Moore (1986) Geological Society America Bulletin, 97, 648–659.
Study by XRD and EBSD of texture and microstructure of the eggs of Chelonoidis chilensis turtle V. Tartalini1, P. Risso1, R.E. Bolmaro1 and M.C. Avalos1 1Instituto de Física Rosario, CONICET-UNR, Rosario, Argentina.
Calcite and aragonite are the two most important and abundant
crystalline forms of CaCO3. Calcite is one of the most abundant
minerals in the earth crust. Aragonite, despite being unstable at
surface conditions of pressure and temperature, is also present in
large mineral deposits. They are almost evenly distributed as
mollusk shell bio mineral constituents, either as sole component or
combined with each other. In eggs, of avian or reptilian origin,
calcite is absolutely dominant. Only some species of land turtles are
known being composed of aragonite. This clear distinction attracted
attention and drove us to characterize turtle eggs in search for
microstructural characteristics and correlation with other species´
eggs.
The studies were performed by scanning turtle eggs of Chelonoidis
chilensis on the Radial-Tangential planes all through the almost 1
mm thickness. Also, X ray pole figures were measure by the
reflection Schultz method.
The structure resulted in a four layered calcite-aragonite composite
material, which probably highly enhance mechanical properties.
Resultant textures are correlated with avian and reptilian egg
results, form the literature and other species characterized by the
same techniques.
Multigrain crystallography as a tool for texture analysis under high pressures and temperatures Joel Vincent Bernier Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
Multigrain crystallography is a recently establish extension of the
traditional single-crystal rotation method that facilitates the
simultaneous analysis of up to 𝒪(1000) crystallites in a single
diffraction volume. The technique was originally developed within
the materials science community as a means for isolating individual
grain responses within bulk polycrystalline samples that were
subject to deformation in situ. More recently, the technique has
been applied to a much broader array of material science problems,
including high-pressure/temperature studies. The multigrain
technique is particularly useful in the context of geophysical
research. Examples include the study of phase transitions and
plasticity, as well as other cases where adequate powder patterns
are difficult to obtain, such as for experiments performed at high
temperatures where grain growth is a complicating factor. While the
measurements required are quite straightforward, the analysis in
not; indeed the scarcity of robust and user-friendly software to solve
ABSTRACTS TUESDAY PM2 – RUDY WENK 62
the deconvolution problem is a major barrier to the more
widespread application of multigrain crystallography in the high
pressure/temperature field. In this talk, the workflow of multigrain
crystallography is presented in the context of the open-source
HEXRD software package. Current capabilities, limitations, and
future extensions are presented alongside several examples. These
include the high-pressure α↔ε phase transition in iron and the
α→ω phase transition in zirconium. The resolution of the method is
shown to isolate the specific transformation mechanisms and
demonstrate the influence of the stress deviator on the variant
selection. Because fully three-dimensional data are available, no
recourse to kinematic modeling or assumptions regarding the
applied stress are required to determine the lattice parameters. In
summary, the technique shows great promise with respect to
ongoing studies of deformation mechanics under high pressure.
This work was performed under the auspices of the U.S. Department
of Energy by Lawrence Livermore National Laboratory under
Contract DE-AC52-07NA27344. Funding through the Laboratory
Directed Research and Development program (10-ERD-053 & 13-
ERD-078) is gratefully acknowledged.
ABSTRACTS TUESDAY PM2 - RECRYSTALLIZATION 63
Symposium R: Crystallization, recrystallization and growth textures Symposium Chairs:
Dr. Rodney McCabe, Los Alamos National Laboratory
Asher Leff, Department of Materials Science and Engineering, Drexel University
Relationship between Zener-Holloman Parameter, Grain Size Refinement, and Texture Evolution during Dynamic Recrystallization of AZ31B Mg Alloy Yuan Li1, Zhenggang Wu2, Peijun Hou1, Zhili Feng2, and Hahn Choo1 1Materials Science and Engineering, University of Tennessee, Knoxville, TN, 37996, USA. 2Materials Science & Engineering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6095
The dynamic recrystallization behavior of a wrought magnesium
alloy plate (AZ31B) with basal texture was studied using the Zener-
Holloman (Z-H) parameter as quantitative criteria for the changes in
deformation and recrystallization mechanisms. A series of
compression tests were conducted for the AZ31B plate samples
along the transverse direction (TD) using a Gleeble system at various
temperature and strain rates covering about eight orders of
magnitude of Z-H parameter. In this paper, we will present the
dynamic recrystallization behavior observed in three Z-H parameter
regimes: namely, low Z, mid Z, and high Z, through which the grain
size refinement changes from homogeneous to bimodal and the
texture changes from the initial basal to off-normal texture.
Moreover, the role of twinning in the grain refinement and texture
formation during recrystallization will also be discussed. The current
study provides a basic understanding of the microstructure
development during the hot working of magnesium alloys including
the friction stir welding.
Incorporating Texture Models in Monte Carlo Simulations of Solidification Theron M. Rodgers1, Efrain Hernandez-Rivera2, Judith A. Brown1, Kyle L. Johnson1, Jonathan D. Madison1, Fadi Abdeljawad1
1Sandia National Laboratories, Albuquerque, USA. 2Army Research Laboratory, Aberdeen Proving Ground, USA.
Recently, a novel simulation technique has been developed to
simulate the formation of grain microstructures in rapid
solidification events found in welding and additive manufacturing.
However, material properties in the initial model implementations
were isotropic. Here we introduce a grain-orientation dependent
model for the incorporation of the anisotropy in cubic materials. The
model allows for the prediction of crystallographic texture during
solidification events. It also accounts for changes in solid state grain
evolution due to misorientations between neighboring grains.
Simulation results will be presented for additive manufacturing and
laser welding simulations.
Sandia National Laboratories is a multi-mission laboratory managed
and operated by Sandia Corporation, a wholly owned subsidiary of
Lockheed Martin Corporation, for the U.S. Department of Energy’s
National Nuclear Security Administration under contract DE-AC04-
94AL85000.
the mechanical property of zirconia coatings and ceramics.
ABSTRACTS TUESDAY PM2 - CHARACTERIZATION 64
Symposium C: Texture and Microstructure Characterization Symposium Chairs:
Dr. Irene Beyerlein, Department of Mechanical Engineering, University of California, Santa Barbara
Dr. Mukul Kumar, Lawrence Livermore National Laboratory
Advances in 3D Grain Mapping with LabDCT Florian Bachmann1, Allan Lyckegaard1, Hrishikesh Bale2, Christian Holzner2, Leah Lavery2 and Erik Lauridsen1 1Xnovo Technology ApS, Køge, Denmark. 2Carl Zeiss X-ray Microscopy, Inc. Pleasanton, CA, USA.
Laboratory diffraction contrast tomography (LabDCT) with a ZEISS
Xradia Versa X-ray microscope opens up new possibilities of non-
destructive 3D and time resolved 4D studies of polycrystalline
material using a laboratory X-ray source. In addition to absorption
contrast and phase contrast tomography, the LabDCT imaging
modality spatially resolves crystallographic orientation of individual
grains. The unique LabDCT approach exclusively closes the gap to
synchrotron 3D grain mapping techniques within laboratory
research. Though, laboratory X-ray sources notoriously suffer from
order of magnitude lower brilliance compared to synchrotron
sources, grain mapping in the laboratory becomes possible by
exploiting the Laue focusing effect. Grain shapes and boundaries of
metals, alloys or ceramics can be characterized fully in 3D. In
particular, crystalline microstructures with negligible or no
absorption or phase contrast can now be studied. This novel non-
destructive laboratory technique enables the observation and
characterization of microstructural response to stimuli (stress,
thermal, radiation) of one and the same sample over time.
Morphological and orientation development of individual grains and
their grain boundaries can be accessed and tracked. Examples in
both 3D and 4D will demonstrate current capabilities of the LabDCT
technique for texture and microstructure characterization.
In-grain orientation spreads in deformed aluminium: 3DXRD-based measurements and finite element simulations L. Renversade and R. Quey
MINES Saint-Etienne, CNRS UMR 5307, Saint-Etienne, France.
The crystal orientations and rotations of about 500 grains of an
aluminium polycrystal deformed in tension were analysed in-situ
using high-energy X-ray diffraction techniques. While the initial
microstructure was mapped by diffraction contrast tomography
(DCT), the lattice rotations of the grains were then followed by 3D X-
ray diffraction microscopy (3DXRD), at strains of 1.0, 1.5, 2.0, 2.5 and
4.5%. First, the average grain orientations were determined from
the positions of the diffraction peaks through standard indexing
techniques. Second, a new method was developed to extract
information on the in-grain orientation distributions from the
spreading of the diffraction peaks. The method assumes a simplified
shape of the orientation distributions and optimizes its parameters
to get the best possible match between the experimental diffraction
patterns and the diffraction patterns simulated from the orientation
distributions using a virtual diffractometer. The preferential
disorientation axes of the orientation distributions were then
analysed in terms of distribution over all grains and correlation to
the grain average orientations. It is shown that the axes
preferentially develop about the tensile direction at strain lower
than 2% and then migrate to a direction normal to the tensile
direction. The results were compared to those obtained by a high-
resolution finite element simulation of the polycrystal deformation.
It is shown that the finite element model properly reproduces the
distributions at largest strains.
Using High Energy Diffraction Microscopy (HEDM) to validate micromechanical fields calculated by FFT based method Vahid Tari1, Ricardo A. Lebensohn2, Reeju Pokharel2, Anthony D. Rollett1 1Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA15213, USA. 2Los Alamos National Laboratory, Los Alamos, NM 87545, USA
High Energy Diffraction Microscopy (HEDM) is both an in-situ and
non-destructive technique. HEDM was used to measure
micromechanical fields such as strain and orientation at the grain
scale developed under macroscopic tensile loading of Ti-7Al. Taking
the 3D image of the experimentally measured initial microstructure
as input, elasto-viscoplastic modeling based on the Micromechanical
Analysis of Stress-Strain Inhomogeneities with Fourier transforms
(MASSIF) was used to compute the micromechanical fields that
develop during loading. To validate the MASSIF calculations, we
compared the calculated fields with the ones measured by HEDM.
The initial comparisons showed that MASSIF can reproduce the
average stress/strain values but poor agreement was found
between calculated and measured fields at the grain scale. The
differences at the grain scale were hypothesized to be caused by the
initial residual stress state that was induced during prior material
processing, and which was not incorporated in the MASSIF
calculation. We used eigenstrain concept to incorporate residual
stress in the MASSIF calculation by converting it to an initial
eigenstrain field. The results reveal that incorporation of residual
stress results in good agreement between calculated and measured
fields at the grain scale, thereby validating the computational
approach.
ABSTRACTS WEDNESDAY - GENERAL 65
WEDNESDAY GENERAL SESSION
Video Presentation: Peter Bunge
Bunge Award Presentation
Bunge Awardee Presentation
ABSTRACTS WEDNESDAY AM - DEFORMATION 66
Symposium D: Deformation Textures Session: Aluminum
Symposium Chairs:
Professor Chadwick Sinclair, Department of Materials Engineering, University of British Columbia
Professor Warren Poole, Department of Materials Engineering, University of British Columbia
Dr. Samantha Daly, Department of Mechanical Engineering, University of California, Santa Barbara
Evolution of deformation texture during flat profile extrusions and its understanding by FEM and crystal plasticity modelling K. Zhang1, A. Segatori2, T. Aukrust3, B. Holmedal4,and K. Marthinsen5 1,4,5Norwegian University of Science and Technology, Trondheim, Norway. 2SAPA Technology, Finspång, Sweden. 3 SINTEF Materials and Chemistry, Oslo, Norway.
The evolution of deformation texture during the flat profile extrusion
process is experimentally and numerically investigated. Extrusion
trials were performed at a relatively low temperature to produce
small flat profiles from a round billet of the aluminium alloy 6063
material. The butt-end (material left in the container) and the profile
were simultaneously water-quenched at the end of extrusion. By the
electron back-scatter diffraction technique (EBSD), the deformation
microstructure and texture were measured in the centre regions both
of the butt-end and of the profile. The profile is of a conventional β-
fibre texture plus some Cube texture, whereas a strong <111> and
weak <100> duplex fibre texture is observed in the butt-end where
close to the inlet of die pocket. Deformation histories for the centre
regions were extracted from the material flow simulation using a
commercial FEM code. Analysing the deformation histories reveals
that it is close to uniaxial tension deformation in the billet until a short
distance to the inlet of pocket, while the material experiences
approximate plane strain deformations when traveling into and
through the pocket of the die. The deformation textures after plane
strain deformation was simulated using the FC-Taylor model, starting
with only <111> and <100> fibre orientations, respectively. The
simulation shows that the <111> fibre will rotate into the beta-fibre
under plane strain deformation. By simulation, the <100> fibre will
concentrate on the Goss orientation with some Cube left. The texture
evolution during this flat profile extrusion can then be well
understood.
Rolling Texture Development in Aluminum-Zinc Solid Solutions B. Merkley, B.J. Diak, and O. Gopkalo Queen’s University, Kingston, Ontario, Canada
Aluminum (Al) has a relatively high stacking fault energy compared
to other face-centered-cubic crystalline elements, and so its
deformation is often characterized by greater potential for cross-slip
and recovery at higher temperatures and organization of a more
cellular work-hardened dislocation structure. It has been observed
that the rolling textures in face-centered cubic polycrystalline metals
tend to transform from so-called pure metal to alloy textures with
increasing stacking fault energy, so deformation texture correlates
directly to stacking fault energy. As a 30th anniversary tribute to the
classic Cu-xZn study by Hirsch and Lücke [1], we recast the problem
for binary Al alloys with 1, 10, and 30wt.%Zn. Zinc (Zn) has a very
high solid solubility in Al of up to 65at.% at 381°C, but at lower
temperatures the Zn solid solution is highly unstable and can
precipitate out or decompose spinodally. Current understanding is
that Zn has no effect on the stacking fault energy of aluminum, so a
priori, rolling of different Al-xZn alloys should result in no variation in
deformation texture. Ingots were cast from book moulds,
homogenized at 428°C for 96 hours and water cooled, cut from the
ingot for rolling, reheated to 428°C for 10 minutes, water quenched
to ice water, warmed to room temperature and promptly rolled 75
and 90% by multiple passes. X-ray texture pole figures were
measured at the mid-plane of the rolled sheet, and the texture
components calculated from the crystallographic orientation
distribution function. Results show a decrease in {112}<11-1> with
Zn content but uncorrelated changes in {011}<21-1> and {123}<63-
4> components. A quantitative understanding of the effect of the
solid solution on the rolling texture development will be presented
in the context of the crystallographic orientation distribution.
[1] J. Hirsch and K. Lücke (1988) Acta metall. 36, 2863. Originally submitted September 28, 1987.
Investigation of inhomogeneous deformation and microstructure during cold rolling in Al-Mg alloys by using 3D marker tracking method M. Kobayashi, M. Nakayama, T. Aoba and H. Miura Toyohashi University of Technology, Toyohashi, Japan.
To understand local inhomogeneous deformation during thermo-
mechanical processing is very important for understanding and
prediction of texture evolution, because localized deformation
would affect not only formation of deformation texture but also
development of recrystallized texture. In this study, development of
inhomogeneous plastic strain in 3D had been measured in cold
rolled Al-Mg alloys that contain small lead particles, which are
marker of local strain measurement, by using synchrotron radiation
micro-tomography. The strain distributions in different Mg content
and rolling ratio were compared with microstructures obtained by
SEM/EBSD. The relationship between local deformation and grain
microstructure is discussed.
New insights on modeling deformation texture and yield strength anisotropy in age hardenable Al-Mg-Si alloys Sumeet Mishra, Manasij Yadav, Kaustubh Kulkarni, N.P.Gurao Indian Institute of Technology, Kanpur, Kalyanpur, India
In the present investigation, effect of coherent directional
precipitates on rolling texture evolution and the resultant yield
strength anisotropy was thoroughly investigated. It was found that
depending upon temper condition a transition in texture from
copper type to brass type can be observed. A copper type texture
ABSTRACTS WEDNESDAY AM - DEFORMATION 67
was observed in the solutionized sample, whereas brass type texture
was found in the peak aged sample. Texture evolution during
different stages of rolling reduction was analyzed quantitatively in
terms of positions of orientation tubes and volume fraction of ideal
texture components. Texture simulations were carried out in the
framework of classical full and relaxed constraint Taylor model to
the more advanced visco -plastic self consistent model and grain
interaction model like LAMEL. It was found that the in the presence
of solute elements, Taylor model gave good agreement with
experimentally determined texture and the yield strength
anisotropy. However, in the presence of coherent precipitates all
the existing models fail to provide satisfactory agreement with
experimental results. A modified Taylor model proposed in the
present work yields much better results than the existing models in
predicting texture evolution and yield strength anisotropy of peak
aged sample. Modified Taylor model considers additional work done
in deforming the precipitates in addition to work done in deforming
the matrix, thereby maintaining compatibility at precipitate-matrix
interface. Due to needle shaped morphology of the precipitates,
some of the shear strain components were relaxed during texture
simulations. Applicability of the model is further showcased by
extending the model to other age hardenable alloys with different
morphology and habit plane of precipitates.
Impact of Texture on Anisotropy and Delamination Cracking in Al-Li Alloys Wesley Tayon1,3, Roy Crooks2, and Ashley Spear3 1NASA Langley Research Center, Hampton VA 23681. 2Black Laboratories, L.L.C., Newport News, VA 23601. 3University of Utah, Salt Lake City, UT 84112
Aluminum-lithium (Al-Li) alloys offer significant performance
benefits over conventional aluminum alloys for aerospace structural
applications. However, their widespread use has been limited due to
highly anisotropic material properties and concerns regarding
delamination fracture. The beta-fiber texture components (namely
the Brass texture component) heavily contribute to anisotropy in
these alloys along with delamination cracking. Delamination is a
secondary form of fracture along flat grain boundaries that occurs as
a result of highly localized deformation. Grain pairs, such as Brass
variants, that develop strong indications of local heterogeneity in
mechanical behavior are more likely to delaminate. State-of-the-art
experimental and computational methods are used to explore the
role of texture in these alloys with respect to anisotropy and
delamination. Results will address localized deformation as a result
of planar slip due to slip system softening within grains and slip
incompatibility at grain boundaries. Ultimately this will provide
designers the information needed to develop appropriate design
standards for these alloys and enable increased deployment in the
aerospace community.
ABSTRACTS WEDNESDAY AM – RUDY WENK 68
Symposium W: A Celebration of the Contributions of Rudy Wenk Symposium Chairs:
Dr. Lowell Miyagi, Geology & Geophysics, University of Utah
Dr. Pamela C. Burnley, Department of Geoscience, University of Nevada, Las Vegas
Dr. Sven Vogel, Los Alamos National Laboratory
A trip with Rudy: from calcite to quartz C.N. Tomé1, R.H. Wenk2
1MST Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA. 2 Department of Earth and Planetary Science, University of California, Berkeley, CA, USA
I started my research trip with Rudy Wenk in 1987, in what was my
first exposure to plasticity of geological materials. Specifically, trying
to understand in terms of slip activity the measured crystallographic
textures of calcite when deforming by shear at different
temperatures. This trip took us through several geological and
metallic systems, with deformation texture being the guiding
evidence and crystal plasticity the compass for trying to infer
information about crystallographic slip and twinning.
Today, 30 years later, still finds us on the same quest but with much
more powerful tools available. Our experimental characterization
techniques and our material deformation models have advanced
enormously in these three decades.
This presentation will summarize the relevant instances of such trip
and will discuss our most recent collaboration on trying to explain
the piezo-crescence mechanism in quartz. Piezo-crescence refers to
the finding that Dauphine twins in quartz can be created or reversed
(detwinned) with the application of a stress field. However, the large
elastic and plastic anisotropy of quartz crystals makes it difficult to
infer the actual stress state in grains from the knowledge of the
applied stress. Our modeling of this process will account for elasto-
plastic anisotropy within the framework of an elasto-visco-plastic
polycrystal model. Predictions of grain reorientation will be
compared to the large available experimental evidence of piezo-
crescence. And we expect to confirm that such the Dauphine twin
transformation is driven by the local stress field in individual grains
via elastic energy minimization.
20 years inspired by Rudy Wenk’s challenges to model texture, microstructure and anisotropy of geomaterials R.A. Lebensohn Los Alamos National Laboratory, Los Alamos, NM, USA
In 1997 I spent 3 months in UC Berkeley working with Rudy Wenk.
Since then, Rudy’s numerous challenges to model and interpret
observations involving texture, microstructure and anisotropy of
materials of the Earth’s interior—obtained by means of
experimental techniques that, in many instances, Rudy himself
pioneered—have been an inspiration for improving our models to
tackle fascinating problems involving low-symmetry crystalline
materials. In this talk I will summarize some our attempts over the
years to explain Rudy’s observations, using two kinds of polycrystal
plasticity formulations, the mean-field viscoplastic self-consistent
model and the full-field FFT-based formulation.
Texture formation in ionic crystals with rock salt structure W. Skrotzki Institute of Structural Physics, Technische Universität Dresden, 01062 Dresden, Germany
Ionic crystals with the rock salt structure (B1) are plastically very
anisotropic and therefore have often been considered as model
materials for rocks. As texture represents a fingerprint of the
thermo-mechanical history of rocks, based on many years of
research on ionic crystals with different ionicity a review is given on
texture formation in this material class as a function of mode and
temperature of deformation. The results will be discussed with
regard to deformation mechanisms (slip system activity), but also
recrystallization and grain growth. Moreover, polycrystal plasticity
simulations will be applied and compared to experiment.
A Method for Including Diffusive Effects in Texture Evolution N.R. Barton1, E. Zepeda-Alarcon2, R.A. Lebensohn3, and M.C. Messner4 1Lawrence Livermore National Laboratory, Livermore CA, USA. 2University of California, Berkeley CA, USA. 3Los Alamos National Laboratory, Los Alamos NM, USA. 4Argonne National Laboratory, Lemont IL, USA.
One of the longstanding challenges associated with homogenization-
based models for the prediction of texture evolution is that they
tend to predict textures that are too sharp. In some cases, the
predicted components are absent in experimental observations.
Here we present a new approach to address at least some aspects of
this issue. We make use of recently developed capabilities for
computation of intragranular fluctuations. These computations,
conducted in a viscoplastic self-consistent (VPSC) framework,
provide a tensorial measure of the trend for misorientation
development inside each single crystal grain representing a
polycrystalline aggregate. These results are then used to drive a
diffusive term in the texture evolution. The method employs finite
elements over Rodrigues space as a convenient means of computing
the operators involved in the evolution of the texture, including the
diffusive operator. Degrees of freedom in the texture evolution are
then associated with a discrete harmonic expansion. In this way, the
finite element resolution controls the accuracy of the integrals for
the operators, and the degree of the discrete harmonic expansion
controls the fidelity of the texture representation. Overall this forms
an attractive and flexible framework. In previous work, this
framework was used with non-local operators to capture twinning,
and here it is extended to include the diffusive contribution from
intragranular fluctuations. Example results will be shown the texture
evolution with and without the diffusive contribution. This work was
performed under the auspices of the U.S. Department of Energy by
ABSTRACTS WEDNESDAY AM – RUDY WENK 69
Lawrence Livermore National Laboratory under Contract DE-AC52-
07NA27344 (LLNL-ABS-719278).
Fabric Transitions in Quartz via Visco-Plastic Self-Consistent Modelling: Axial Compression and Simple Shear under evolving Strain L. F. G. Morales1, D. Mainprice2 and K. Kunze2 1ETH Zurich, ScopeM, Zurich, Switzerland. 2 Geosciences Montpellier, Montpellier, France.
Quartz is a common crustal mineral that deforms plastically in a
wide range of temperatures and pressures, leading to the
development of different types of crystallographic preferred
orientation (CPO) patterns. In this contribution we present the
results of an extensive modelling of quartz fabric transitions via
visco-plastic self- consistent (VPSC) approach. For that, we have
performed systematic simulations using different sets of relative
critical resolved shear stress of the main quartz slip systems. We
have performed these simulations in axial compression and simple
shear regimes variable strains up to a maximum of Von Mises
equivalent strain of ~ 350% (γ=6). In these models we assume that
the aggregates deformed exclusively by dislocation glide. Some of
the predicted CPOs patterns are similar to those observed in
naturally and experimentally deformed quartz, and some patterns
are developed in a wide condition variation. Nevertheless, some
classical CPO patterns usually interpreted as resulting from
dislocation glide (e.g. Y-maxima due to prism <a> slip) are developed
just under very specific conditions. In addition, we report potentially
new preferred orientation patterns that might develop in high
temperature conditions, both in axial compression and simple shear.
We have demonstrated that CPOs generated under axial
compression are usually stronger that those predicted under simple
shear, due to the continuous rotation observed in the later
simulations. The fabric strength depends essentially on the
dominant active slip system, and normally the stronger CPOs result
from dominant basal slip in <a>, followed by rhomb <a> and prism
[c] slip, whereas prism <a> slip does not produce strong fabrics,
unless in very high strains.
The Androgynous Twins of Zinc S. Merkel1, N. Hilairet1, C. Tomé2
1Université de Lille, 59000 Lille, France. 2Los Alamos National Laboratory, Los Alamos, NM 87545, USA
Zn is a hexagonal metal with a large c/a ratio under ambient
conditions (c/a=1.856). Under ambient testing conditions,
deformation is predominantly accommodated by basal <a> slip and
by {10-12} <11-23> compression twinning. Remarkably, increasing
hydrostatic pressure drastically reduces the c/a ratio of Zn, a
phenomenon known as anomalous pressure dependence. As a
consequence of the unit cell dimensional change, the compression
twin is predicted to become a tensile twin when c/a<√3 at P>9 GPa.
In this work we strain-cycle a wire of pure Zn in the D-DIA
deformation press under multiple superimposed hydrostatic
pressures ranging between 3 and 17 GPa. Over this pressure range,
the c/a ratio of Zn will go over the compressive-tensile transition.
During deformation, the state of the sample is monitored in-situ
through powder x-ray diffraction, allowing the extraction of texture
and sample stress. Elasto-visco-plastic polycrystal simulations of the
cyclic process allow us to interpret the experimental data and to
elucidate the type and strength of the crystallographic deformation
mechanisms.
The purpose of this work is to elucidate the active deformation
modes as a function of pressure. Specifically: 1) to determine if
detwinning is a possible mechanism at 3 GPa pressure when Zn is
cycled in tension-compression; 2) to find out if at a pressure state
where c/a~√3 only basal slip is active or whether another slip
mechanism operates, and which; 3) to find out whether {10-12}<11-
23> tensile twins are active in Zn when c/a<√3.
ABSTRACTS WEDNESDAY AM - TRANSFORMATIONS 70
Symposium T: Transformation Textures Symposium Chair:
Dr. Michael Roach, Biomedical Materials Science, University of Mississippi Medical Center
Variant selection mechanisms and quantitative prediction of transformation textures in steel T. Tomida1, Y. Onuki2 and S. Sato2,3
1Ibaraki Prefectural Government, Tokai, Japan, 2Frontier Research Center for Applied Atomic Sciences, Ibaraki University, Tokai, Japan, 3Graduate School of Science and Engineering, Ibaraki University, Hitachi, Japan
Variant selection mechanisms in the phase transformation in steel
have been investigated to quantitatively predict transformation
textures. Two variant selection mechanisms have been recently
introduced by the author and his coworkers [1,2]. The one is that
the variant having Kurdjumov-Sachs (K-S) orientation relation or the
one near the K-S with two adjacent parent grains is preferentially
selected, which we call the double K-S relation (DKS) [1]. More
recently the other mechanism based on the elastic anisotropy in
neighboring matrices has been introduced for martensite
transformation [2]. The elastic energy required for the
accommodation of the shape strain due to displacive transformation
does not depend on variants when the medium to accommodate it
is immediate parent grains, in which martensite grows, since all the
variants are crystallographically equivalent to the immediate parent
grain. However, if the medium is neighboring non-immediate parent
grains (without orientation relationship) or preexisting martensite,
the elastic energy can be dependent on variants due to the elastic
anisotropy of the medium. Thus, in this mechanism, the variant with
a lower elastic energy in adjacent parent grains and preexisting
martensite is preferentially selected. While the selection mechanism
by DKS is dominant for the diffusive transformation, the latter
mechanism by elastic anisotropy should be dominant for martensite
transformation. With these mechanisms and the spherical-
harmonics-based calculation method for transformation textures,
the textures by diffusive and displace transformations can be
quantitatively well predicted. Such mechanisms and calculation
results based on recent diffraction experiments via a neutron
diffractometer, i-MATERIA, in J-PARC will be presented in the
conference.
[1] T. Tomida, M. Wakita, M. Yoshida, N. Imai (2008) Proc. 15th ICOTOM, 325.
[2] T. Tomida, to be published.
β-Mn transformation and orientation relationship in austenite-based FeMnAlC low-density steel S.-J. Park1, K. Lee2, J.-Y. Kang1, J.Y. Park1, J. Moon1, A.D. Rollett3 and H.N. Han2 1Korea Institute of Materials Science, Changwon, Republic of Korea. 2Seoul National University, Seoul, Republic of Korea. 3Carnegie Mellon University, Pittsburgh, USA
Low-density steels usually contain aluminum which provides density
reduction effect. Among the low-density steels, austenite-based
FeMnAlC steels have shown superior mechanical properties and
weight reduction rate. In the austenite-based FeMnAlC steels, β-Mn
phase can be formed depending on chemical composition and heat
treatment conditions, which is known to be detrimental to ductility.
However, little information about the transformation from austenite
(γ) to β-Mn is available including nucleation, growth behavior and
orientation relationship. In this work, formation of β-Mn phase in
Fe-30Mn-11Al-0.9C alloy during aging at 550oC was investigated. The
microstructure was observed using electron backscatter diffraction
(EBSD) analysis and transmission electron microscopy (TEM). The β-
Mn phase grew extensively into γ grains showing Widmanstätten-
type morphology. Lattice expansion of γ and carbon enrichment in γ
caused by β-Mn formation was examined using X-ray diffractometry
(XRD) and electron probe micro-analyzer (EPMA). The
crystallographic orientation relationship between γ and β-Mn was
analyzed by orientation relationship stereogram (ORS) using EBSD
data. The ORS results were verified by TEM diffraction patterns at
the interface boundaries.
Austenite Reconstruction Elucidates Prior Grain Size Dependence of Toughness in a Low Alloy Steel C. Ranger1, V.H Tari1, A.D Rollett1, M.J. Merwin2, and S. Farjami2 1Carnegie Mellon University, Pittsburgh, USA. 2U.S. Steel Research and Technology Center, Munhall, USA.
Texture and grain size distribution of austenite phase at high
temperature have distinct effects on mechanical properties of steel
alloys at room temperature, but measurement of austenite at high
temperature is not a trivial task and is not always feasible. So,
developing a technique predicting austenite texture and grain size at
high temperature is highly desirable. In this work, we review several
samples of pipe steels with different martensitic microstructures at
room temperature and wide variations in toughness results. These
variations were not explained by the microstructure and
morphology of the room temperature martensite phase. We
developed and applied an algorithm to reconstruct the parent
austenite at high temperature from martensite microstructure at
room temperature. This technique successfully reconstructed prior
austenite grains in samples with different microstructures. Our
results clearly indicate the distribution of austenite grain size in each
sample strongly depends on processing history. Furthermore, the
results revealed that variations in toughness of each sample were
correlated to texture, grain orientation spread, and grain size of
austenite.
Variant Selection at Parent Phase Grain Boundary
Nucleation During -to- Phase Transformation in Low Carbon Steel L. A. I. Kestens1,2, J. Galan Lopez2,3 and Kees Bos4 1Ghent University, Ghent, Belgium. 2Delft University of Technology, Delft, The Netherlands. 3M2i, Materials Innovation Institute, Delft, The Netherlands. 4Tata Steel R&D, IJmuiden, The Netherlands.
In a previous work, it was shown that the occurrence of a double
Kurdjumow-Sachs (KS) orientation relation for a ferrite grain
nucleating at a grain boundary of the parent austenite structure,
strongly favors the nucleation propensity, as the double coherent
ABSTRACTS WEDNESDAY AM - TRANSFORMATIONS 71
interface of the newly formed phase boundary drastically reduces
the phase boundary energy. This condition implies a variant
selection rule, as only one out of the 24 possible variants will comply
with the requirement of a double KS orientation relation. This rule
was included in a crystallographically resolved version of a cellular
automaton model (CA) that was published before and which was
successfully applied to model the kinetics of the -to- phase
transformation for low-carbon steels.
For each parent phase grain boundary, the crystallographic
misorientation was calculated and it was assumed that the driving
force exhibits a Gaussian dependence on the orientation distance
from the double KS orientation relation. This nucleation rule
produced a near random ferrite product texture when the parent
austenite texture was random. In case the parent texture was
dominated by a strong cube component, the product texture was
characterized by a (weak) rotated cube component ({001}<110>). In
absence of variant selection, the product texture displayed three
components: the rotated cube component, the Goss component and
the rotated Goss component ({001}<110>, {110}<001> and
{110}<110>, respectively). The disappearance of the latter two
components in the product texture because of the double KS
nucleation restriction, corresponds remarkably well with
experimental observations of ferrite hot band textures in low-carbon
steels, finish rolled above the non-recrystallization temperature.
Crystallographic Reconstruction of Parent Austenite Twin Boundaries in a Lathe Ferritic Steel Stephen Cluff1, David Fullwood1, Tracy Nelson1 and Rongjie Song2 1Department of Mechanical Engineering, Brigham Young University, Provo UT, USA. 2ArcelorMittal Global R&D—East Chicago Automotive Products, East Chicago, IN, 46312, USA
The study of post-transformation microstructures and their
properties can be greatly enhanced by studying their dependence on
the grain boundary content of parent microstructures. Recent work
has extended the crystallographic reconstruction of parent austenite
in steels to include the reconstruction of special boundaries, such as
annealing twins. These reconstructions present unique challenges,
as twinned austenite grains share a subset of possible daughter
variant orientations. This gives rise to regions of ambiguity in a
reconstruction. A technique for the reconstruction of twin
boundaries is presented here that is capable of reconstructing 60°
<1 1 1> twins, even in the case where twin regions are comprised
entirely of variants that are common between the twin and the
parent. This technique is demonstrated in the reconstruction of an
x80 lathe ferritic steel. The reconstruction approach utilizes a
delayed decision making approach, where a chosen orientation
relationship is used to define all possible groupings of daughter
grains into possible parents. These overlapping, inclusive groupings
(called clusters) are compared to each other individually using their
calculated parent austenite orientations and the topographical
nature of their overlapping regions. These comparisons are used to
uncover possible locations of twin boundaries present in the parent
austenite. This technique can be applied to future studies on the
dependence of post-transformation microstructures on the special
grain boundary content of parent microstructures.
Reconstruction of austenite microstructures in steels by global optimization of misorientation functions T. Nguyen-Minh1,2, E. Gomes2, R.H. Petrov1,2 and L.A.I. Kestens1,2
1Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands. 2Department of Electrical Energy, Metals, Mechanical Construction and Systems, Ghent University, Tech Lane Ghent Science Park – Campus A, Technologiepark 903, B9052 Zwijnaarde, Belgium
During the phase transformation from austenite to martensitic or
bainitic ferrite in steels, crystallographic orientations of product
grains are defined by their parent orientations and the orientation
relationship between parent and product crystals. Therefore,
boundaries between ferrite variants from the same parent austenite
in a microstructure, are distinguished by their special
disorientations, rather than the random misorientation. By analyzing
the misorientation distribution between ferrite product grains, prior
austenite grain boundaries are able to be revealed and the
microstructure of the parent austenite can be reconstructed. In this
study, austenite microstructure reconstruction is carried out by
global optimization of two separate misorientation functions. By
optimization procedures, it is able to determine the average
orientation relationship and consequently the parent orientations
for each EBSD pixel. Application of the reconstruction model is
illustrated by calculations of prior-austenite microstructures in
quenched samples of low carbon steels and Fe-29 wt.% Ni alloy.
ABSTRACTS WEDNESDAY AM - ENGINEERING 72
Symposium A: Texture and Anisotropy in Advanced Engineering Processes and Materials Session: Advanced Processing – Accumulated Roll Bonding
Symposium Chairs:
Professor Tracy Nelson, Department of Mechanical Engineering, Brigham Young University
Dr. Ashley Spear, Department of Mechanical Engineering, University of Utah
Study of the texture developed by ARB and CARB processes on an AA5754/AA6061 composite K. Verstraete, A.-L. Helbert, F. Brissetand T. Baudin ICMMO, SP2M, Université Paris-Sud, Université Paris-Saclay, UMR CNRS 8182,91405 Orsay Cedex, France
Accumulative Roll-Bonding (ARB) [1], as a severe plastic deformation
process, is suitable to refine the microstructure and as a
consequence to enhance mechanical properties (Hall-Petch law).
Besides, change of strain path is known as another way to
strengthen metals. Thus, Cross ARB (CARB) [2], which combines both
ARB and rotation of the Rolling Direction (RD), is a very interesting
process.
The present work aimed to compare ARB and CARB processes in a
textural way, both at room and hot temperature. At room
temperature, elaborated composites show a clear separation.
Indeed, while ARB samples show a typical FCC rolling texture (S,
Dillamore, Brass and Goss), CARB samples develop a texture
embodied by a strong ND (Normal Direction)-rotated Brass with
minor Dillamore and S components. The singular symmetry of the
ND-rotated Brass allows an isotropy of the yield stress in the two
main directions RD and TD (transverse direction) of the sheet plan.
At hot temperature, and whatever the process, the texture is mainly
represented by the rotated Cube component, allowing in addition a
good isotropy of the yield stress. Finally, whatever the temperature,
the yield stress is found higher in CARB than in ARB.
[1] Y. Saito, H. Utsunomiya, N. Tsuji& T. Sakai, (1999) Acta Materialia47 579.
[2] S. Kaneko, K. Fukuda, H. Utsunomiya, T. Sakai, Y. Saito& N.
Furushiro, Materials Science Forum (2003) 426‑432 2649.
Texture evolution in accumulative rolled bonded Mg-Nb composites from polycrystal to single crystal layers Daniel J. Savage1, Irene J. Beyerlein2, Rodney J. McCabe3, John S. Carpenter3, Nathan A. Mara3, Sven C. Vogel3, Nan Li3, Marko Knezevic1 1University of New Hampshire, Durham, US. 2University of California, Santa Barbara, US. 3Los Alamos National Laboratory, Los Alamos, US.
Phase interfaces within interface-dominated, immiscible hexagonal
close-packed/body-centered cubic (HCP/BCC) materials can result in
an extraordinary combination of strength and ductility, a significant
improvement compared to those of the constituent phases. This
paper demonstrates the potential to convert a Mg alloy sheet with
poor formability and strength into a much more formable and
stronger material when it is processed into an ultrafine-layered
bimetallic sheet. To this end, the severe plastic deformation
technique accumulative roll bonding was used to refine stacks of
high-purity BCC Nb and HCP 4-5wt% Mg alloy sheet from mm to um
size layer thicknesses. To offer insights into the role of temperature
and strain-rate in large strain rolling of Mg based multilayer
composites, we present the evolution of microstructure, texture and
strength of this unique material for several processing paths.
Texture and Microstructure of Laser Butt-Welded AZ61Mg/Ti clad sheet H. Inoue and M. Okuno Osaka Prefecture University, Sakai, Japan.
We successfully fabricated a titanium-clad magnesium alloy sheet by
using warm roll-bonding and subsequent annealing as a candidate of
new lightweight materials. In order to apply this material to a
practical use such as a welded pipe and a large panel, laser butt
welding was performed for a two-layer AZ61Mg/Ti clad metal sheet
consisting of AZ61 magnesium alloy and Grade 1 titanium which
have very different melting points. The two-layer structure that was
characteristic of the clad metal were maintained even in the weld
zone after laser butt welding. The magnesium alloy and titanium
layers around an interface of the base metal exhibited equiaxed
recrystallized grain microstructure and nearly equiaxed grain
microstructure including deformation twins, respectively. In
contrast, the magnesium alloy and titanium layers of the weld zone
showed coarse solidified structure elongated parallel to nearly the
thickness direction and microstructure consisting mainly of coarse
grains, respectively. Laser welding changed texture of the titanium
layer from the TD-split type rolling texture with basal planes inclined
toward the transverse direction to the transformation texture with
various β to α transformed orientations on cooling. On the other
hand, basal texture of the magnesium alloy layer was changed to a
near {-1 2 -1 0} <0001> orientation as a main component by laser
welding. This suggests that the texture evolution would be
attributed to the direction of grain growth during solidification.
Relationship between Initial Hydrogen Absorption Properties and Microstructures of Mg/Cu Super-Laminate Composites with Different Accumulative Roll Bonding Cycles K. Tanaka1, D. Nishino2, 3, R. Kondo2 and H.T. Takeshita2 1National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Japan. 2Kansai University, Suita, Japan. 3Lawson Inc., Tokyo, Japan.
Magnesium has been considered as a good candidate for hydrogen
storage applications, because of its high hydrogen storage capacity
(7.6 mass %), low cost, light weight and high abundance in the
earth’s crust. Moreover, MgH2 has other attractive properties, such
as reversibility of hydrogen absorption/desorption and recyclability.
The main drawbacks for the use of MgH2 are slow hydrogen
absorption/desorption kinetics and high temperatures of operation
(> 573 K) associated with its strong thermodynamic stability. To
solve these problems, many efforts have been made recently, such
ABSTRACTS WEDNESDAY AM - ENGINEERING 73
as appropriate alloying of magnesium, adding catalysts, and
manufacturing nano-crystalline powder.
Mg/Cu super-laminate composites (SLCs) (Mg2Cu composition)
made by accumulative roll bonding (ARB) show fast kinetics and
good durability of hydrogen absorption/desorption compared with
Mg2Cu powder. We have reported the improvement of hydrogen
absorption/desorption kinetics, its relations with microstructures,
and the effect of initial structures of Mg/Cu SLCs on hydrogen
absorption/desorption properties in previous papers for Mg2Cu-H2
system.
During initial hydrogenation, hydrogenation of Mg and alloying Mg
with Cu followed by hydrogenation of Mg2Cu occur competitively. It
is reported that sever plastic deformation (SPD) such as high-
pressure torsion (HPT) and equal-channel angular pressing (ECAP)
can enhance atomic diffusion and promote solid-state reactions
because of an increase in the density of lattice defects such as
vacancies, dislocations and grain boundaries. It is important to know
the effect of ARB.
In this paper, we examined the relationship between initial
hydrogen absorption properties and microstructures of Mg/Cu SLCs
with different cold-rolling cycles.
Three types of specimens were prepared by changing ARB cycles.
They were cold-rolled with 10, 20, and 30 cycles, respectively.
Hydrogen absorption properties were measured with a Sieverts’
type instrument. Microstructures such as the thickness of Mg and Cu
layers and dislocations were observed with SEM and TEM. The
formation mechanism of microstructures in Mg/Cu SLCs during
initial hydrogenation through competitive reactions was estimated
by evaluating the activation energy for the layer growth process of
Mg2Cu in Mg/Cu SLCs.
The activation energies did not show a significant difference
between Mg/Cu SLCs with different ARB cycles. However, the
average thickness of Mg + Cu layers in as-rolled Mg/Cu SCLs became
thinner as the ARB cycle number increased. Initial hydrogen
absorption properties and microstructures of Mg/Cu SLCs after
initial hydrogenation were very different between Mg/Cu SLCs with
10 ARB cycles and over 20 ARB cycles. Hydrogenation of Mg was
major in Mg/Cu SLCs with 10 ARB cycles and that of Mg2Cu over 20
cycles. From the above, it is considered that the fineness of
microstructures in as-rolled Mg/Cu SLCs has large influence on initial
hydrogenation properties and microstructure formation processes.
Influence of Texture on Layer stability in Ti/Al ARB Composites J. Scharnweber1, J. Romberg2, C.-G. Oertel1, J. Freudenberger2, L. Schultz2 and W. Skrotzki1 1Institut für Strukturphysik, Technische Universität Dresden, D-01062 Dresden, Germany. 2Leibniz-Institut für Festkörper- und Werkstoffforschung, D-01171 Dresden, Germany.
Ti/Al laminated sheets have been produced by Accumulative Roll
Bonding (ARB [1]) at ambient temperature, both with and without
intermediate annealing. A maximum of eight and six ARB cycles was
conducted, respectively.
Without annealing, pronounced shear banding across the layers
commonly observed in ARB composites [e.g. 2] occurs after few ARB
cycles. This transforms the layered structure into an Al-matrix with
embedded Ti-fragments. During subsequent ARB processing the
thickness reduction of the latter becomes very inhomogeneous
being overall significantly retarded compared to the geometrical
reduction of the sheet. An annealing of 90 minutes at 450°C in
between rolling cycles was found to promote homogeneous
deformation of both phases during ARB resulting in Ti/Al-composites
with stable layers with a minimal spacing of about 4 µm after eight
ARB cycles [3].
The evolution of microstructure and local texture of both Al and Ti
was studied by electron backscatter diffraction, the bulk texture was
measured by neutron diffraction.
It was found that during intermediate annealing recrystallization
occurs in both Al and Ti retarding microstructural refinement. The
bulk texture of Al is dominated by S, copper/Dillamore and brass
components. With intermediate annealing each rolling and
annealing step strengthens and weakens the rolling components,
respectively. In Ti, the usual 30°-tilt of the c-axis around the rolling
and towards the normal direction was observed with maxima at
either <10-10> or <11-20> being parallel to the rolling direction.
During the intermediate annealing, the latter component becomes
dominant.
The talk will focus on the microstructural and textural evolution with
regard to annealing temperature and ARB cycle, respectively. The
influence of texture on layer stability will be discussed and
compared to that of other factors, e.g. the hardening rate.
Acknowledgment: Thanks are due to Dr. W. Gan (FRM II, TUM) for
experimental support. Financial support by Forschungs-
Neutronenquelle Heinz Maier-Leibnitz (FRM II) is gratefully
acknowledged. The work has been carried out within the Saxon
Excellence Cluster “European Centre for Emerging Materials and
Processes (ECEMP)”.
[1] Y. Saito, H. Utsunomiya, N. Tsuji & T. Sakai (1999) Acta Mater. 47 579.
[2] D. K. Yang, P. Cizek, P. Hodgson & C. Wen (2010) Scripta Mater. 62 321.
[3] W. Skrotzki, A. Eschke, J. Romberg, J. Scharnweber, T. Marr, R. Petters, I. Okulov, C.-G. Oertel, J. Freudenberger, U. Kühn, L. Schultz & J. Eckert (2014) Adv. Eng. Mater. 16 1208.
Deformation behavior and strength of bulk Zr/Nb nanolayered composites Daniel J. Savage1, Irene J. Beyerlein2, Rodney J. McCabe3, John S. Carpenter3, Nathan A. Mara3, Sven C. Vogel3, Nan Li3, Jordan Weaver3, Marko Knezevic1 1University of New Hampshire, Durham, US. 2University of California, Santa Barbara, US. 3Los Alamos National Laboratory, Los Alamos, US.
In this work, we report on the deformation behavior and strength of
two-phase 50/50 Zr/Nb nanolayered composites after cold rolling to
a range of rolling reductions. The starting material is a bulk sheet of
Zr/Nb layered composite made by accumulative roll bonding with a
ABSTRACTS WEDNESDAY AM - ENGINEERING 74
nominal individual layer size h = 92 nm. Final layer thicknesses after
cold rolling were on the order of 5 nm. Substantial edge cracking
was observed during rolling of sheets with h > 41 nm, but was
minimal for h < 41 nm. Transmission electron microscopy and
neutron diffraction reveal a continuous layered structure of hcp-Zr
and bcc-Nb and a weakening texture h < 41 nm. Nanoindentation
hardness, spherical indentation, and micro pillar compression
indicate a non-decreasing increase in strength with decrease in h,
with the finest material achieving a strength of at least 1.5 times
that of the coarse-layered Zr/Nb composite and an order of
magnitude increase in strength over that of either constituent. The
results offer insight into interface driven deformation mechanisms
relevant for the microstructural design of hcp-based nanolaminates.
ABSTRACTS WEDNESDAY AM - CHARACTERIZATION 75
Symposium C: Texture and Microstructure Characterization Symposium Chairs:
Dr. Irene Beyerlein, Department of Mechanical Engineering, University of California, Santa Barbara
Dr. Mukul Kumar, Lawrence Livermore National Laboratory
Concurrent in situ HREBSD and HRDIC analysis of an AlCu oligocrystal using selectively electron transparent microstamping Tim Ruggles1, Jake Hochhalter2, Andrew Cannon3, Geoff Bomarito2 1National Institute of Aerospace. 2NASA Langley Research Center. 31900 Engineering
HREBSD (high resolution electron backscatter diffraction) and HRDIC
(high resolution digital image correlation) methods provide
complementary information valuable for understanding
deformation at the microscale, namely local elastic strain and local
total strain respectively. However, conventional patterning
techniques required for HRDIC disrupt the diffracted electrons
generated for HREBSD, making concurrent analysis via these two
techniques at the same length scale problematic. A new technique
is introduced here to combine these two techniques in situ:
urethane rubber microstamping. Microstamping applies a thin,
amorphous polymer pattern that is thin enough to be effectively
transparent to the high energy (20 keV) diffracted electrons,
meaning that electron backscatter diffraction patterns suffer no
measureable loss of detail. At the same time, the patterns are still
thick enough to be imaged at lower accelerating voltages for HRDIC.
Results from concurrent HREBSD and HRDIC performed on an AlCu
oligocrystal tensile specimen deformed in situ will be presented.
Effect of grain orientation on hydrogen embrittlement of high manganese steel Daehwan Kim and Chong Soo Lee
Graduate Institute of Ferrous Technology, Pohang University of Science and Engineering, Pohang, Republic of Korea.
This study aims to investigate dependence of hydrogen
embrittlement characteristics on grain orientation of high
manganese steel. Single crystal micropillars were fabricated by
focused ion beam (FIB) and electron backscatter diffraction (EBSD) in
the grain matrix which orientation is the major texture component
of fcc; Goss, brass, copper, cube, E, and F. Hydrogen was charged
into micropillar by cathodic charging method. Compression tests
using nanoindenter were followed for uncharged- and hydrogen-
charged micropillar. Scanning electron microscope (SEM) and
transmission electron microscope (TEM) analysis were conducted for
microstructure evolution characterization. The flow behavior of
micropillar varies with hydrogen charging and grain orientation.
Corresponding to hydrogen enhanced localized plasticity (HELP)
theory, lowered yield strength and early onset of plastic
deformation occurred in hydrogen-charged micropillar.
Twinning and slip activity differ with grain orientation or fiber, which
leads to anisotropic behavior in hydrogen-charged condition. From
this study, grain orientation which causes incompatibility and
decohesion on the grain boundary is defined and possibility of
macro-texture control which enhances hydrogen embrittlement
resistance is proposed.
3D EBSD Characterization of Al5083 Spall Damage T. Sano1, J. P. Ligda, T. R. Walter, and C. L. Williams U.S. Army Research Laboratory, Aberdeen Proving Ground, MD, USA.
Spall cracks in aluminum 5083 plates were formed by a high strain
rate plate impact experiment. To characterize the deformation and
spall cracks in 3D, two multi length-scale characterization techniques
were applied. The first was to non-destructively characterize a
region of interest with micro x-ray computed tomography (micro-
CT), and secondly, destructively serial section the same region,
incorporating electron backscattered diffraction (EBSD) with a
femtosecond laser coupled to a focused ion beam. The EBSD dataset
is reconstructed into a 3D volume, and the results combined with
those of the micro-CT to fully describe the spall damage.
Crystal Orientation Examination of Patterns Formed by Micro-indentation of Cube-textured Aluminum Foil Using SAXS and Temperature Changes S. Saimoto1, M. A. Singh2, M. R. Langille1 and C. Gabryel1
1Mechanical and Materials Engineering, Queen’s University, Kingston, ON. Canada, K7L3N6. 2Physics, Eng. Physics & Astronomy, Queen’s University, Kingston, ON Canada, K7L3N6
Recent use of nano-indentation to assess work-hardening of
complex microstructures of dual phase steels as a function of
deformation, together with crystal plasticity finite element methods
to simulate the bulk properties, gives rise to the question of the role
of crystallite orientation during indentation. Such studies using
nano-indentation on µm-sized grains are difficult. To elucidate the
role of possible parameters, micro-indentation of cube textured Al
capacitor foils were examined. These foils of 106 µm thickness are
convenient for small angle X-ray scattering (SAXS) examination and
the orientation around the indent can be examined by back-
scattered electron diffraction (EBSD). Moreover, the deformation
around the indent can be assessed to confirm the existence of
rotated lattice structures analogous to those observed near µm-
sized particles within the matrix. Due to the cube orientation, the
indents can be formed with the diagonal of the Vickers indenter
parallel to <100> or <110> directions. For an isotropic plastic
material, the diagonal lengths Ld should be √2, that of the width
between the parallel interface traces Lw, that is Ld / Lw = 1.41. The
indentations at various temperatures up to 160°C show that this
ratio is more or less constant for the <110> orientation but larger
than that for <100> one. Ratios approaching isotropy is found for
<100> at 80° and 120°C. The reason for the anisotropy is because of
the variation in latent hardening with different intersecting slip
systems and the resulting formation of stacking fault tetrahedral
which recovers above room temperature. These results together
with the lattice findings using SAXS will be described.
ABSTRACTS WEDNESDAY AM - CHARACTERIZATION 76
Study of the microstructure of a cold rolled interstitial free steel through X-Ray Diffraction and Electron Back-Scatter Diffraction E. A. Benatti1, N. S. De Vincentis1, M. Avalos1, H. G. Brokmeier2, N. Schell3 and R. E. Bolmaro1 1Laboratorio de Ciencia de los Materiales, Instituto de Física Rosario CONICET-UNR, Rosario, Argentina. 2Institut für Werkstoffkunde und Werkstofftechnik, TU Clausthal, Clausthal-Zellerfeld-Helmholtz-Zentrum Geesthacht, GEMS Outstation, Hamburg, Germany. 3Helmholtz-Zentrum Geesthacht, GEMS-Outstation DESY, Hamburg, Germany.
Hot and cold rolling are used for large-scale industrial processes, and
can produce a rather complex intermixing of grain refinement,
dislocation arrays and stacking faults, distorting the crystallographic
lattice and interfering with the motion of other defects. X-Ray
Diffraction (XRD) allows a global characterization of the
microstructure, through the analysis of the height and shape of the
diffraction peaks. Moreover, synchrotron XRD enables such analysis
in relation with the sample orientation. Electron Back Scatter
Diffraction (EBSD) studies, on the other hand, allows a more direct
although local kind of study. In this work we use XRD to determine
the texture of an Interstitial Free Steel, cold rolled to 70 % reduction,
and relate the measured texture with the defect storage on different
texture components through diffraction peak broadening analysis.
To that end we create Generalized Pole Figures (GPF) of Full Width
Half Maximum (FWHM), and use the pole figure to ODF inversion
method in the FWHM GPFs to find a generalized Orientation
Distribution Function (ODF) which can be compared with the regular
ODF used in texture analysis. Finally, we compare these results with
EBSD measurements of the same sample to obtain a more direct
estimation of the anisotropy of the defect storage of the sample. We
found that the gamma fiber, usually present in rolled BCC materials
is the component which tend to store more defects, although X-Ray
diffraction methods fail to distinguish which kind of defects are the
ones being stored. The typical alpha fiber was also found but it was
rather cleaner from defects. Both results are in agreement with
previous literature results for similar materials.
Characterization of local plastic strain during deformation from electron backscatter diffraction data – limitations and possibilities A. Godfrey, X. Hong, C.L Zheng Laboratory of Advanced Materials (MoE), School of Materials Science and Engineering, Tsinghua University, Beijing, China.
A critical review of the use of electron backscatter pattern
diffraction (EBSD) for investigation of deformed microstructures will
be presented. In particular, a comparison of grain scale and local
scale measures of plastic displacement, based on vertex tracking and
digital image correlation, with several misorientation-based EBSD
parameters will be given. The non-unique relationship between local
misorientation (on the scale of the deformation microstructure) and
plastic strain will be highlighted, as will some potential limitations of
commonly used measures for characterization of deformed
microstructures that arise as a result of the high spatial resolution
available with modern EBSD systems. Examples will be given from in-
situ tensile deformation of both FCC and HCP metals.
ABSTRACTS THURSDAY AM - PLENARIES 77
THURSDAY AM PLENARY SESSION
Advanced parent reconstruction: an efficient tool to optimize TMTs by a better control of the parent and subsequent inherited microtexture L. Germain1,2, N. Gey1,2 and M. Humbert1 1LEM3, University of Lorraine, Metz France. 2Laboratory of Excellence for Design of Alloy Metals for Low-mass Structures (‘DAMAS’ Labex), University de Lorraine, France
Optimizing the microstructure in a material which undergo a phase transformation during the thermomechanical treatment requires the control of
both the parent and the child microstructure. In this framework, the reconstructions of the parent microtexture from EBSD maps measured on the
transformation product have been proven to be very useful. Indeed, in many cases, such a method gives access to essential characteristics of the
parent microstructure: Crystallographic texture, grain size, local orientation spread (with an angular resolution of 1.5-3°), deformation mechanisms,
deformed/recrystallized fraction... [1]
In this presentation, the main principles of our reconstruction tool 'MERENGUE 2' and its benefits are recalled [2]. Several application examples are
presented, especially in Titanium and in martensitic and bainitic steels. Finally, the simultaneous knowledge of the parent and child microtextures
allows a finer analysis of the transformation mechanisms. In this framework 'DECRYPT' software (Direct Evaluation of CRYstallographic Phase
Transformation) has been developed. It is dedicated to analyzing the orientation data inherited by OR-based phase transformations. It is illustrated
on different application examples to assess variant selection mechanisms at a local scale: variant clustering in Steels, selective grain boundary
precipitation in Titanium...
[1] L. Germain, N. Gey, R. Mercier, P. Blaineau & M. Humbert, Acta Mater. (2012) 60, 4551–4562. [2] Merengue2, Software, http://lionelgermain.free.fr
The Texture Between the Grains: Statistics of Grain Boundaries and Grain Boundary Networks Christopher A. Schuh Department of Materials Science and Engineering, MIT, Cambridge MA USA
The treatment of crystallographic texture has become very advanced, with a mathematical toolkit developed to the point where inverse design
problems in texture control are possible and increasingly realizable. By contrast, the control of “grain boundary textures”, i.e., the distribution of
interface crystallographies in polycrystals, is certainly less developed, although such “grain boundary engineering” has an extremely strong value
proposition in improving many material properties. This talk will review progress over the past decade or so on the tools used to visualize and
mathematically describe grain boundary distributions. With an understanding of the misorientation space topology and symmetries, some
simplified mathematical constructs become possible, and some special cases from within the full 5-parameter space also exhibit satisfying
topological properties. With a spectral representation of misorientations, it is possible to treat more complex microstructural features, such as the
well-known short-range correlation of misorientations imposed at, e.g., triple junctions. And finally, by handling the emergent distributions of
microstructural ‘units’ such as triple junctions, a path to defining a complete “grain boundary network space” has now been opened. Although
early in their development, such approaches lead naturally to the posing of inverse problems in grain boundary network design for optimum
properties. The talk will end by projecting the trajectory of these recent developments forward in time, to identify opportunities for major new
future contributions.
ABSTRACTS THURSDAY AM - DEFORMATION 78
Symposium D: Deformation Textures Session: Advanced Materials
Symposium Chairs:
Professor Chadwick Sinclair, Department of Materials Engineering, University of British Columbia
Professor Warren Poole, Department of Materials Engineering, University of British Columbia
Dr. Samantha Daly, Department of Mechanical Engineering, University of California, Santa Barbara
Role of crystal orientation on deformation of Zr: A Molecular dynamics study K V Mani Krishna, D Srivastava and G K Dey Bhabha Atomic Research Centre, Mumbai, India
Plastic deformation is known to be highly orientation sensitive. This
orientation sensitivity of deformation gets further accentuated in
case of hexagonal materials. Present study is an attempt to bring out
the role of crystal orientation on the dislocation nucleation behavior
of Zr (hcp material). The role of crystal orientation, deformation
temperature and sense of loading (i.e. tensile vs compressive
deformation) on dislocation nucleation were studied. Nano
indentation simulations were used for modeling the heterogeneous
nucleation. More than 35 crystal orientations (representing various
loading directions) covering large portion of fundamental zone of
hcp symmetry have been used to bring out the quantitative
information of critical stresses for dislocation nucleation in case of
homogenous and heterogeneous dislocation nucleation.
Simulations have brought out high degree of orientation
sensitiveness in dislocation nucleation stresses in case of both
homogenous and heterogeneous nucleation events. Simulations
have shown that it is easier to nucleate <a> type dislocations than to
induce dislocations with burgers vector having <c> component. This
is in agreement with the experimental observation of higher density
of <a> type dislocations in comparison to <c> type in Zr. However,
no orientation had resulted in the formation of <c+a> dislocations
indicating that experimentally observed <c+a> dislocations could be
due to interaction of existing <a> and <c> type of dislocations. The
dislocation loop structure of heterogeneously nucleated loops
differed considerably with that of those that got homogenously
nucleated. While the former have grown in size with deformation,
latter have essentially increased in number density but not in size
with increase in deformation.
Texture evolution modeling of Ni alloys by crystal plasticity including twinning M. Ito1 and C.A. Schuh2 1Mitsubishi Materials Corporation, Kitamoto Saitama, Japan. 2Massachusetts Institute of Technology, Cambrige MA, USA
The texture evolution during the deformation of Ni alloys are
evaluated using crystal plasticity. We incorporate twinning
deformation within the crystal plasticity framework in order to
simulate both the Cu-type texture of rolled pure Ni and the Brass-
type texture of rolled Alloy C22. The calculation results have very
similar characteristics in their crystal orientation distributions to the
experimental results. The relationship between material model
parameters and the stacking fault energy are discussed as it pertains
to texture evolution.
Texture evolution in clock-rolled Zr during dynamic extrusion J.P. Escobedo1, CP Trujillo2, E.K. Cerreta2, R.A. Lebensohn2, GT Gray2 1UNSW Canberra, Canberra, ACT, Australia. 2MST –8, Los Alamos National Laboratory, Los Alamos NM, USA
The mechanical response and associated texture evolution in clock-
rolled Zr during dynamic tensile extrusion have been investigated.
Bullet-shaped specimens were tested in a modified Taylor-anvil
apparatus with their extrusion direction aligned to either the in-
plane (IP) rolling or the through thickness (TT) direction of the plate.
The post extrusion microstructure and texture evolution were
examined using electron backscatter diffraction microscopy (EBSD)
and modeled using the visco-plastic self-consistent (VPSC) model.
Our results show that the extrusion deformation was accomplished
through collaborative interaction of twinning and slip and their
relative activity greatly depends on the initial texture. In addition,
twinning dominates the texture evolution during the early stages of
deformation; this resulted in the development of the (10-10)
extrusion texture in all samples, independent of the initial texture.
Texture as a guideline for XRD residual stress investigation B. Kania Insititute of Metallurgy and Materials Science Polish Academy of Sciences, Kraków, Poland
Presentation covers the results of two ongoing science projects,
combining the XRD texture and strain measurements at constant
penetration depth, modelling the texture-induced mechanical
anisotropy of engineering materials and a generalized least-square
fitting of the stress tensor. Compiled methodology of stress
investigation relies on materials texture data not only in the analysis
of strain-stress relationship, but also in the process of planning the
measurements by proper selecting of pole figures points for which
strains will be gauged. This allows effective characterization of stress
state in the thin films, graded samples, materials with pronounced
texture or materials strongly relating all of that issues. With
presented method it is possible to simplify the strain-stress analysis
to the point of reliably utilization of the simplest models for
materials initially exposing themselves as very complicated fields of
study.
Martensitic transformation, twin boundary and phase interface mobility of directionally solidified Ni-Mn-Ga alloys during compression by EBSD tracing Y.C. Dai, L. Hou and X. Li* State Key Laboratory of Advanced Special Steels (Shanghai University), Shanghai 200072, China
Directional solidified Ni-Mn-Ga alloy with orderly arrayed austenite
and non-modulated martensite (NM) was formed due to
ABSTRACTS THURSDAY AM - DEFORMATION 79
microsegregation between dendrite arm and interdendritic space,
leading to preferred orientation <001>A and <110>M coexistence at
ambient temperature. The stress induced martensite transformation
took place due to the increase of martensite transformation
temperature under step-wise uniaxial compression. The detwinning
progress accompanied with dislocation mobility was easy to carry on
the twin planes at 45° incline to compression axis, compared with
the twin planes paralleled to compression axis in the dominant
twinned groups. The martensite transformation and reorientation of
variants were investigated by electron backscattering diffraction
(EBSD) tracing.
ABSTRACTS THURSDAY AM – DEFORMATION 80
Symposium D: Deformation Textures Session: Steels – Hot Rolling
Symposium Chairs:
Professor Chadwick Sinclair, Department of Materials Engineering, University of British Columbia
Professor Warren Poole, Department of Materials Engineering, University of British Columbia
Dr. Samantha Daly, Department of Mechanical Engineering, University of California, Santa Barbara
Texture evolution of duplex stainless steel UNS S32205 under hot working conditions D. Lindell1, D. Martin1, B. Hutchinson1 and A. Kaijalainen2 1Swerea KIMAB AB, Stockholm, Sweden. 2Materials and Production Engineering, University of Oulu, Finland.
Rolled duplex stainless steels show pronounced anisotropy in
mechanical properties that originates from both morphology and
texture. Especially important is the relatively strong rotated cube
texture that develops in the ferrite phase. The sluggish
recrystallization behavior of the ferrite phase implies that the final
texture is strongly inherited from earlier process steps. Hence, the
cast structure and the overall prior temperature and strain history
need to be taken into account to accurately model ferrite texture
evolution in rolled material. The current work focuses on a simplified
case suitable for comparison with existing crystal plasticity models.
The material used in the study is a duplex stainless steel
corresponding to UNS S32205 produced by powder metallurgy and
hot isostatic pressing to provide a texture-free, fine grained and
equiaxed starting structure. Hot deformation was simulated in plane
strain using a Gleeble 3800 from which sub-sized impact toughness
specimens were prepared. The experimental textures are compared
to simulated textures using various crystal plasticity codes. The
anisotropy in impact toughness is discussed on basis of the
morphology, texture and compared to commercially cast and hot
worked material.
Texture evolution after dynamic recrystallization in Fe-Mn-Si steel T. Toyoda1, N. Sugiura1, N. Yoshinaga1, J. Tamori2, H. Miura2 1Nippon Steel & Sumitomo Metal Corporation, Steel Research Laboratories, Futtsu, Japan; 2Toyohashi University of Technology, Department of Mechanical Engineering, Toyohashi, Japan
In hot rolling processes of steel, various phenomena such as work
hardening, work softening, dynamic recovery, dynamic
recrystallization (DRX) and etc. leads to change microstructure and
mechanical properties. It is well known that multiple- or single-peak
work softening in the flow curves are induced by extensive
occurrence of DRX. The oscillation of the flow stress is, therefore,
closely related with the changes in the microstructure and texture
that strongly affects mechanical properties of steel. DRX behavior
and evolved microstructure sensitively changes by addition of
elements. Si is frequently employed to improve yield and tensile
stresses as well as thermal stability.
The effects of Si addition on hot deformation behavior and
microstructural evolution in Fe-1.5Mn-0.01Si and Fe-1.5Mn-0.5Si
(mass%) steels were precisely studied by means of EBSD. Fe-1.5Mn-
0.5Si steel showed less texture evolution and finer DRX grains
compared to those in the former one. These differences are
presumed to be the effects of retarded grain coarsening and
increased twinning by Si addition. In short, Si addition caused i)
solute drag effect to reduce grain-boundary migration, ii) higher
probability of twinning in phase to contribute to orientation
randomization.
Texture Changes of Electromagnetic Ferritic Stainless Steels by Compressive Deformation at High temperatures Y. Onuki1, S. Sato1, M. Uchida1, T. Naruse2, Y. Kim2, T. Ebata2, S. Fujieda3 and S. Suzuki3 1Ibaraki University, Ibaraki, Japan. 2Tohoku Steel Co., Ltd., Miyagi, Japan. 3Tohoku University, Sendai, Japan.
Precipitation-hardened ferritic stainless steels are used for
electromagnetic actuators of engines, as these steels reveal the high
strength and soft magnetic properties. The hardening of these
ferritic stainless steels occurs by formation of nanoscale precipitates
of NiAl in during aging after solution treatment. Furthermore, it is
required to control the texture of these steels, since it is known that
the soft magnetic properties are obtained in the ferritic steels with
<100> fiber texture. However, texture control of the ferritic stainless
steels has not been attempted so far. In this study, the texture
change in a ferritic stainless steel by deformation at high
temperatures. As it has been shown that the texture of ferritic Fe-Si
alloys is significantly changed by deformation conditions such as
temperature and strain rate [1], the compressive deformation
processes were applied to the texture control of the present
stainless steels.
Samples used were a ferritic steel of Fe-14.5Cr-3Ni-2Mo-1Al-1Si (in
mass%). The specimen for uniaxial compression deformation test
was a cylinder of φ10 x H15mm. They were compressed under
different strain rates at high temperatures between 973 and 1073 K.
The microstructure and texture of the deformed sample were
characterized by analyzing the cross section of the cylindrical
samples using electron backscatter diffraction (EBSD). The volume
fractions of <100> and <111> texture components in the sample
were mainly investigated in this work.
The texture analysis results by EBSD showed that the fraction of
<100> texture component increases with decreasing strain rate, and
reveals the maximum in the samples deformed at the strain rate of
5x10-4s-1.
The dependences of microstructure and texture on the deformation
condition seen in the current study is similar to what observed in the
previous studies [1, 2]. Namely, lower density of small angle grain
boundary and higher fraction of <100> oriented region are achieved
with lower strain rate. This suggests the activation of PDGG
(preferential dynamic grain growth). The PDGG is achieved by the
ABSTRACTS THURSDAY AM – DEFORMATION 81
strain-induced grain boundary migration due to the difference of
stored energies between different crystal orientations. Since <100>
has lower Taylor factor than <111>, another deformation texture
component during uniaxial deformation, lower dislocation density in
<001> than in <111> is expected. Therefore, it can be concluded that
<100> oriented grains expand by consuming <111> oriented grains
so that the total stored energy in the bulk is reduced. The current
result indicates that the PDGG can be applied as the texture
controlling mechanism not only in binary or ternary alloys but also in
practical alloy steels including various elements.
[1] Y. Onuki, R. Hongo, K. Okayasu & H. Fukutomi (2013) Acta Mater., 61, 1294.
[2] Y. Onuki, S. Fujieda, S. Suzuki & H. Fukutomi (2017) ISIJ Inter., 57, in press.
ABSTRACTS THURSDAY AM - TRANSFORMATIONS 82
Symposium T: Transformation Textures Symposium Chair:
Dr. Michael Roach, Biomedical Materials Science, University of Mississippi Medical Center
Analysis of texture memory, surface-effect-induced transformation texture and variant selection in low graded electrical steels P. Yang, C. Gu, N. Wang, J. Wang and W. Mao School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, China, 100083.
The textures in commercial non-oriented electrical steels are all
optimized by the control of deformation and recrystallization
parameters irrespective of their grades or silicon contents. The
favorite {100} texture in such condition takes at maximum only
about 20% in volume fraction. In contrast phase transformation
combined with deformation can lead to nearly 80% volume fraction
of {100} oriented grains which is confirmed by many authors.
Texture memory effect is often detected in steels during
transformation influenced by rolling process. Yet texture memory
does not equal to the presence of strong transformation texture, it is
often seen that transformation texture is quite different to the
rolling texture of ferrite before transformation. If transformation
proceeds uniformly in steel sheets, {111} texture or nearly random
texture can also be resulted; If it takes place by nucleation at sheet
surface in pure hydrogen after rolling, strong {100} texture can be
obtained, so that magnetic properties can be improved.
Based on the fact that strong {100} texture can be produced by
rolling and subsequent transformation annealing in low grade
electrical steels, this work aims to investigate the degree of texture
memory during transformation in cast slabs of low grade
electrical steels containing dominant columnar grains and its
influence on subsequent rolling and transformation annealing. The
purpose of this study is to provide fundamental principles for the
potential application of low grades of non-oriented steels.
The EBSD measurement on ferritic columnar structure of cast slabs
at room temperature reveals that about 70% regions are columnar
grains with nearly {100} orientations and 30% are small equal-axed
grains formed within coarse columnar grains manifesting a texture
memory effect without the influence of external deformation. A lot
of 3 misorientations are present between coarse columnar grains
and small grains indicating the K-S orientation relationship and the
variant selection rule of reducing transformation strain as much as
possible. However, there are still a lot of small grains which don’t
share special misorientations with surrounding grains. The formation
of this kind of grains is attributed to the austenitic variants formed
during the first transformation or the orientation fluctuation
caused by deformation during casting. As early 70% columnar
grains are retained during cooling of cast slabs without the influence
of external deformation, it is seen that the thermal stress needed for
variant selection, which is produced during cooling, is rather low.
Texture memory in AISI 321 austenitic stainless steel A.A. Tiamiyu, J.A. Szpunar and A.G. Odeshi University of Saskatchewan, Saskatoon, Canada.
In this study, AISI 321 austenitic stainless steel was cryo-rolled at -
196 ℃ to 50 % thickness reduction to completely transform the γ-
austenite phase to αʹ-martensite. The cryo-rolled sample was
subsequently annealed in the temperature range of 650 – 800 ℃ for
0.5 – 480 minutes to reverse the αʹ-martensite back to γ-austenite
and develop ultrafine grain (UFG) structure at an optimum annealing
condition. Although the mechanism of reversion in 600 ℃-annealed
specimen is different from those of higher temperatures, high
resolution EBSD and XRD texture results shows that ζ-fibre
({110}<uvw>) is the major texture component of austenite grains in
the UFG structure and it is stronger at 650 ℃ than higher
temperatures (700, 750 and 800 ℃) used in this study. The strong
intensity of ζ-fibre in UFG is attributed to texture memory in AIS 321
i.e. the ability of the steel to memorize the crystallographic
orientation of the deformed austenite, rather than the conventional
as-received austenite phase that is random. TiC precipitates which
are more stable at 650 ℃ than 700, 750 and 800 ℃ and unreversed
triple junction αʹ-martensite played a major role in the development
of UFG structure by Zener pinning of grain boundaries. Average
austenite grain sizes of 0.22 and 0.31 microns were obtained at an
optimum annealing conditions of 650 ℃ for less than 480 minutes
and 750 ℃ for 10 minutes, respectively.
Crystallographic Texture and Microstructural changes in a weld of two Zry-4 plates: Variant selection Model A Moya Riffo, M.A. Vicente Alvarez and J.R. Santisteban Neutron Physics Department - Bariloche Atomic Center - CNEA-CONICET, S.C. Bariloche, Argentina.
This work presents a detailed description of the microstructural and
crystallographic texture changes observed in the transition region in
a weld between two Zircaloy-4 cold rolled and recrystallized plates
[1]. In the heat affected zone (HAZ) we observed the development of
Widmanstätten microstructures, typical of the α(hcp) to β(bcc)
phase transformation. Associated with these changes a rotation of
the c-poles is found in the HAZ and fusion zone. While the base
material shows the typical texture of a cold rolled plate, with their c-
poles pointing 35º apart from the normal direction of the plate in
the normal-transversal line, in the HAZ, c-poles align along the
transversal direction of the plate and then re-orient along different
directions, all of these changes occurring within a length scale in the
order of mm.
The microstructural and texture changes along the HAZ were
interpreted as arising due to the effect of differences in the cooling
rate and β grain size on the progress of the different α variants
during β−•α transformation. Fast cooling rates and large β grains are
associated to weak variant selection during the β−•α
transformation, while slow cooling rates and fine β grains result in
strong variant selection. Also in a particular region of the HAZ,
where phase transformation was incomplete, a texture memory
effect was evidenced.
ABSTRACTS THURSDAY AM - TRANSFORMATIONS 83
A theoretical model was proposed to describe the origin of the
variant selection mechanism. This model is based on the evaluation
of the energy advantage for nucleation of α embryos in an infinite β
matrix associated to the interaction between the transformation
strain misfit and the elastic response of the texture medium [2]. The
model was able to reproduce the observed textures after the β−•α
transformation, and also the changes on this texture due to
differences in the cooling rate.
[1] A. Moya Riffo, et al., Journal of Nuclear Materials (2017), http://dx.doi.org/10.1016/j.jnucmat.2017.02.015
[2] M. Humbert and N. Gey, Acta Materialia. 51 (2003) 4783–4790.
The effect of cold work on the texture of a Zirconium alloy after fast β-cycling C-T. Nguyen1, J. Romero2, A. Ambard3, M. Preuss1, J. Quinta da Fonseca1 1Materials Performance Centre, The University of Manchester, Manchester, UK. 2Westinghouse Electric Company, Columbia, South Carolina, USA. 3EDF R&D, Centre de Renardière, Moret-sur-Loing, France
The texture of cold worked zirconium nuclear fuel cladding after the
rapid β-heating cycle, characteristic of loss-of-coolant and reactivity-
initiated accidents (LOCA and RIA), is different from that of the
material that starts off in the recrystallized condition. Whereas the
final α-texture of the cold-worked sample is essentially random, that
of the recrystallized material is a much stronger with 0002 poles in
transverse direction. The aim of the work reported here was to
understand the origin of this effect.
Electrical resistivity was used to measure the kinetics of the phase
transformation during the fast β-cycle, which had the heating rate of
100ºCs-1, the maximum temperature of 1100ºC with holding for 3
seconds and the cooling rate of 50ºCs-1. This thermal cycle was
achieved via resistive heating in an electro-thermal-mechanical
tester (ETMT), which also ensured no stress was applied. EBSD was
used to measure the textures before and after transformation and
synchrotron X-ray diffraction was used to measure the texture
evolution during the cycle.
The experiments showed that cold-worked samples transform at
higher temperature and have lower β volume fraction at a given
temperature than the recrystallised samples. The reconstructed
high-temperature β texture after β-grain growth of the cold-worked
material was found to be much weaker than that of the
recrystallised. The in-situ measurements show there is a difference
in the transformed β-textures during phase transformation
αα+ββ of the two materials and this difference emerges more
during β grain growth.
By comparing the experimental α-textures and predicted ones
without variant selection on cooling, it can be shown that this
difference in β texture could explain most of the differences in the
transformed texture. Furthermore, when the material starts in the
recrystallized condition, there is evidence of increased variant
selection on cooling.
These differences in the kinetics of phase transformation, the final
α-textures, the reconstructed β textures and the variant selections
in the two conditions can be explained by the different textures and
grain boundary network, on which the new phases preferably
nucleate, just before the phase transformation. These findings will
improve the accuracy of inputs from microstructure and texture of
zirconium claddings to LOCA/RIA models. They also suggest that cold
work can have a very different effect on phase transformation
textures from those previously reported for titanium alloys with
similar crystal structures.
Texture Evolution during Hot-Rolling of Dual Phase Zirconium Alloys
C.S. Daniel1, P.D. Honniball2, L. Bradley2, M. Preuss1 and J.Q.
Fonseca1
1University of Manchester, Manchester, United Kingdom. 2Rolls-Royce plc, Derby, United Kingdom.
Dual-phase α + β Zr-Nb alloys have a higher strength and fracture
toughness than single phase α-alloys and develop different textures
during thermo-mechanical processing. Dual-phase Zr-alloys tend to
form a strong transverse (TD) texture of the basal pole, the origin of
which is poorly understood and cannot be predicted by crystal
plasticity texture evolution models. This is probably because the
microstructure and texture evolution of these dual-phase alloys
arises from complex interactions between the α (hexagonal-close-
packed, hcp) and β (body-centred-cubic, bcc) phases, during both
deformation and phase transformation.
The work presented here is an investigation of the texture evolution
in an industrially used Zr-2.5Nb alloy during hot-rolling. The aim was
to determine the relative roles of plastic strain partitioning between
phases, the activity of the different deformation modes and phase
transformation on the final texture. The effect of temperature
(700 ℃ to 825 ℃), reduction ratio (50 % to 87.5 %) and strain
rate, along with the influence of starting texture, was characterised
using time-of-flight neutron diffraction and EBSD techniques. The
transverse texture component, with prismatic alignment {1120} <
1010 >, strengthens significantly with greater rolling reduction at
the higher temperature. Software reconstruction of EBSD
orientation maps, using the Burgers relationship, shows how the
strength of this texture component varies across the material
depending on the orientation of the large prior-β grains.
A more detailed characterisation of the high temperature
deformation and phase transformation behaviour was made on a
hot-rolled Zircaloy-4 + 7 wt.% Nb alloy. Since a greater proportion of
metastable βZr is retained to room temperature, a snapshot of the β → α phase transformation can be captured, distinguishing high
temperature primary α grains from the nucleation and growth of
secondary α variants. Previous work had shown that the strong
transverse texture of the transformed α is at least in part caused by
variant selection, with a mechanism determined by the high
temperature breakup of the prior-β grains. By analysing these
structures in 3D, using a plasma focused ion beam (PFIB) and taking
sequential EBSD slices, it was found that the degree of breakup is
affected by the distribution of primary α laths within each β grain.
Further analysis showed that the orientation of primary α influences
the breakup behaviour of the β grains, which then affects variant
ABSTRACTS THURSDAY AM - TRANSFORMATIONS 84
selection through preferential growth selection of secondary α upon
cooling. These findings suggest new ways in which current models
can be developed to enable the successful prediction of hot rolling
texture in these alloys.
ABSTRACTS THURSDAY AM - ENGINEERING 85
Symposium A: Texture and Anisotropy in Advanced Engineering Processes and Materials Session: Advanced Processing – Additive Manufacturing
Symposium Chairs:
Professor Tracy Nelson, Department of Mechanical Engineering, Brigham Young University
Dr. Ashley Spear, Department of Mechanical Engineering, University of Utah
Anisotropy and Microstructure in 3D Printed IN 718 S. Subedi1, A. Palomares2, J. Molina-Aldareguía2, J. Llorca2,3, S. Cong1 and A.D. Rollett1 1Carnegie Mellon Univ., Pittsburgh, USA. 2IMDEA Materials Institute, Madrid, Spain. 3Polytechnic University of Madrid, Spain.
Additive manufacturing (AM) via 3D printing of metals has increased
in importance in a short space of time, largely because of the
demonstrated ability of powder bed machines to make parts
reliably. Nevertheless, there are many open questions relating to
microstructure, porosity, precipitation state and texture. Some of
these issues are illustrated from work on printing heat exchangers
for use with supercritical CO2 in Inconel 718 where the
microstructures exhibit strong orientation gradients, very low twin
densities and irregular grain shapes. The low twin densities are
consistent with previous work, which established that annealing
twins are created predominantly during primary recrystallization.
Unless heat treated, AM materials represent the result of direct
solidification albeit at cooling rates approaching 106 °/sec. The high
cooling rates allied with solidification, thermal shrinkage and creep
explain the residual plastic deformation. By milling out micro-pillars
in a polished surface and performing micro-compression tests, the
anisotropy of the material was investigated. The results suggest that
the strength is sensitive to the occurrence of single versus multiple
slip, as well as the presence of grain boundaries near the top of the
pillar.
In-situ Investigation of Microstructure Evolution during Annealing in Ti-6Al4V Alloy Produced by Additive Manufacturing S.C. Vogel1, S. Takajo1,2, A. Pesach3, O. Yeheskel3, E. Caspi3, E. Tiferet3 1Los Alamos National Laboratory, Los Alamos, NM, U.S.A. 2JFE Steel Corporation, Kurashiki, Japan.3Nuclear Research Center Negev, Israel
Selective laser melting (SLM) and electron beam melting (EBM) are
AM processes, in which three dimensional metallic objects are
obtained by melting the ingredient powder materials layer by layer.
Due to high solidification rates of small melt volumes, AM products
may result in off-equilibrium microstructures, in which macro-strain,
micro-strain and directional growth are present. However, recently
it was shown that, the micro-structure of the EBM sample is found
free of preferential orientation, whereas in the SLM sample
significant preference towards the hexagonal basal plane. Rietveld
analysis of our preliminary measurements (carried out at HIPPO,
LANL) on AM TiAl6V4 samples, produced by both SLM and EBM,
show a dependency between the AM process and the content of β-
phase and the strength of α-phase texture in post processed
samples. It was found that the weight percentage of the β-phase at
the end of one SLM process was ~10 times higher than in similar
samples that were produced with EBM or SLM with different
machine. We expand on the ambient condition measurements and
report also on our finding of the microstructure evolution during
annealing at temperatures up to 1100C.
Effect of Microstructure and Texture on the Elasto-viscoplastic Deformation of Dual Phase Titanium Structures Tugce Ozturk, Anthony D. Rollett Carnegie Mellon University, Pittsburgh, USA.
Ti-6Al-4V, one of the most popular titanium alloys used in direct
metal additive manufacturing (AM), exhibits highly heterogeneous
characteristics when produced by electron beam melting (EBM), an
established powder bed AM technique. The thermal gradient
accompanying this manufacturing process directly affects the
cooling rate of the melted powder, hence the resulting
microstructure and the mechanical properties. We present a
computational approach for creating a large structure-property
database for dual phase titanium alloys, through the use of a
synthetic microstructure generation method and a mesh-free fast
Fourier transform based micromechanical model that operates on
an image of the microstructure. 3D synthetic microstructures are
generated based on additively manufactured Ti-6Al-4V
characteristics, which are further modified to expand the database
for features of interest, e.g. different parent/daughter textures. Sets
of titanium hardening parameters are extracted from literature, and
the relative effect of the chosen microstructural features is
quantified through comparisons of average and local field
distributions. The response is found to be the most sensitive to
alpha phase fraction and the prior beta texture, such that the
increase in alpha phase enhances the tensile strength, and an
increased strength of prior beta (001) texture decreases the tensile
strength.
Texture development in steel components produced by Wire Arc Additive Manufacturing C. Goulas1, 2, 4, W. Ya3, 4, R.H. Petrov2, 5, M.C.M. Hermans2 and I.M. Richardson2
1Materials innovation institute, Electronicaweg 25, 2628 XD Delft, the Netherlands. 2Delft University of Technology, department of Materials Science and Engineering, Mekelweg 2, 2628CD Delft, the Netherlands. 3University of Twente, Chair of Applied Laser Technology, MS3 Department, Engineering Technology, P.O. Box 217, 7500 AE Enschede, The Netherlands. 4Rotterdam Additive Manufacture Fieldlab (RAMLAB), Scheepsbouwweg 8 - K03, 3089 JW, Rotterdam, The Netherlands. 5Gent University, Department of Materials Science and Engineering, Technologiepark 903, 9052 Zwijnaarde, Gent, Belgium
Wire and arc-based additive manufacturing (WAAM) processes are
novel technologies that are used for the construction of complex
large scale 3D-structures. WAAM is essentially a welding-based
technique, which means that WAAM products often exhibit
solidification microstructures. Solidification texture depends on the
ABSTRACTS THURSDAY AM - ENGINEERING 86
local heat flow directions and competitive grain growth in one of the
six <100> preferred growth directions. As WAAM products are
manufactured by layer-by-layer metal deposition, microstructural
and functional grading becomes possible by selection of appropriate
process conditions that determine the heat and material flow
direction. In this study, we demonstrate that through the variation
of deposition parameters and by applying external cooling, the local
heat flow can be controlled, which enables us to create desired local
texture by controlling the orientation of grain growth. Process data
and the thermal history of the locations studied, which is monitored
with a thermal camera, provide input for a better understanding for
controlling of the textures development during WAAM. For the
purpose of this study, vertical walls were deposited using low alloy
and austenitic stainless steel wires. Samples were cut from several
heights of these walls and were analysed by means of Electron Back
Scatter Diffraction (EBSD). A better understanding and control of the
solidification textures during WAAM process can help to improve
the product design, by taking into account the new possibilities of
manufacturing of additively manufactured functional materials.
Role of texture in tensile, compressive, cyclic, and fracture behavior of direct metal laser sintered Inconel 718 Saeede Ghorbanpour and Marko Knezevic Department of Mechanical Engineering, University of New Hampshire, Durham, NH 03824, USA.
This paper describes the main results from a comprehensive
investigation into the role of texture on strength and cyclic tension–
compression to large strains as well as low and high cyclic fatigue
behavior of direct metal laser sintered (DMLS) Inconel 718
superalloy. The results are reported for different initial
microstructures created by variation in the deposited direction. To
further investigate the effects of initial microstructure, a set of
samples underwent hot isostatic pressing. To have a reference for
the behavior of DMLS Inconel 718, a set of wrought Inconel 718
samples in the same condition was also tested, and the results
critically compared against the results for the DMLS materials. In
order to understand particularities pertaining to behavior of the
material at the grain-scale, a dislocation density based hardening
law is developed and used within elasto-plastic self-consistent
crystal plasticity model to simulate all the tests except the high cyclic
fatigue. The modeling results in conjunction with detailed
microstructural characterization reveal the significant role played by
porosity, annealing twins as well as reverse dislocation motion and
backstresses on the material behavior.
ABSTRACTS THURSDAY PM1 - BOUNDARIES 87
Symposium B: Misorientation Textures at Grain Boundaries and Interfaces Symposium Chairs:
Dr. Eric Homer, Department of Mechanical Engineering, Brigham Young University
Dr. Srikanth Patala, Department of Materials Science and Engineering, North Carolina State University
Grain Boundary Texture, Energy, and Curvature as a Function of Lattice Misorientation and Grain Boundary Plane Orientation X. Zhong, M.N. Kelly, and G.S. Rohrer Carnegie Mellon University, Pittsburgh, PA, USA.
Grain boundary properties depend on five independent
crystallographic parameters. Three can be associated with the
lattice misorientation and two with the grain boundary plane
orientation. Three-dimensional orientation mapping makes it
possible to measure grain boundary relative areas (texture), grain
boundary energies, and grain boundary curvatures as a function of
all five grain boundary parameters. Here, we describe techniques
for these measurements and present an over view of findings from a
variety of metals and ceramics. One of the general findings is that
the texture is stronger in the space of grain boundary plane
orientation than it is in the space of misorientations. Furthermore,
there are persistent correlations in materials that form by normal
grain growth. For example, the grain boundary energy and the grain
boundary population have an inverse logarithmic correlation. For
most types of boundaries (those that are non-singular), the mean
curvature has an inverse linear correlation to the grain boundary
energy. However, singular grain boundaries such as coherent twins
are characterized by low energy, low curvature, and high
populations. Examples will be cited from studies of Ni, bcc Fe, fcc
Fe, and SrTiO3.
Grain Boundary Plane Structure-Property Relationships and Fundamental Zones Eric R. Homer1, Srikanth Patala2, Jonathan Priedeman1, David Olmsted3 1Brigham Young University, Provo, USA. 2North Carolina State University, Raleigh, USA. 3University of California, Berkeley, USA.
A full crystallographic description of a grain boundary requires 5
parameters, 3 for misorientation and 2 for boundary plane
orientation. Typical characterizations focus on misorientation, but
boundary plane plays an important role in structure-property
relationships. The presented work focuses on describing the GB
crystallography, including boundary plane orientation, in
fundamental zones and demonstrates that structure-property
relationships naturally emerge from this form. Structure-property
relationships of energy, excess volume, and mobility are
demonstrated for a range of GB types. The fundamental zone
representation also suggests possible trends over the full 5D space
among similar disorientation axis grain boundaries. Finally, the
various mobility trends in Σ3 grain boundaries are explained in the
context of this fundamental zone representation.
Segregation Affecting the Evolution of Primary Recrystallization Textures in a Ternary Fe-Si-Sn Alloy N. Mavrikakis1,2, M. Dumont1, D. Mangelinck1, M. Descoins1, W. Saikaly3 1Aix-Marseille Université, CNRS, IM2NP UMR 7334, Marseille, France. 2ArcelorMittal Research SA, Maizières-lès-Metz, France. 3ArcelorMittal Global R&D Gent, Belgium
The effect of Sn addition on the primary recrystallization of cold
rolled Fe-3% Si alloys is investigated. Texture evolution and
misorientation distributions are analyzed on partially recrystallized
samples using the electron backscatter diffraction technique. Sn was
found to affect the microstructure, throughout the thermal
treatment of the materials, by refining the grains and altering the
texture. In the presence of Sn, the intensity of {111}<uvw> grains is
reduced through all stages of recrystallization, while that of
{100}<uvw> and {hkl}<100> grains is increased. The favored growth
of these latter grains is most likely due to a combination of
mechanisms that involve the presence of some high mobility grain
boundaries (with low Σ). Indeed, the Σ5 boundaries were observed
to increase in frequency with Sn through all stages of
recrystallization. Additionally {100} grains were found to be most
frequently correlated with Σ5 interfaces, which might be due to
geometrical considerations. The most probable explanation for the
increase of Σ5 is that Sn segregates to random high-angle grain
boundaries and retards their migration, whereas little segregation
takes place to the Σ5 boundaries, favoring the growth of grains that
are bounded by this boundary. Site-specific grain boundary Sn
segregation analysis was conducted with atom probe tomography to
confirm the proposed mechanism.
Inferring Grain Boundary Structure-Property Models from the Effective Properties of Polycrystals via Inverse Problem Theory C. Kurniawan, O.K. Johnson Brigham Young University, Provo, USA.
The structure and spatial arrangement of Grain Boundaries (GBs)
have been proven to strongly affect the properties of polycrystalline
materials such as corrosion, creep, weldability, superconductivity,
and diffusivity. The properties of GBs are typically correlated with
their crystallography via measurements conducted on bicrystals.
However, because of the high dimensionality of the GB spaces, the
use of this one-by-one approach to construct predictive structure-
property models is taxing, both experimentally and computationally.
We propose an efficient method to infer GB structure-property
models from measurements of the effective properties of
polycrystals. We provide an idealized case study in which a
structure-property model for GB diffusivity is inferred from noisy
simulation results in two-dimensional microstructures and the
accuracy of the inferred model is quantified.
ABSTRACTS THURSDAY PM1 - BOUNDARIES 88
Mechanisms of Grain Growth in 7 and 9 Grain Boundaries with Mixed Mobility Trends J.L. Bair1, E.R. Homer1 Brigham Young University, Provo, UT, USA
Grain boundary migration in 7 and 9 grain boundaries are
simulated at temperatures from 100 K to 1000 K under various
synthetic driving forces using Molecular Dynamics. The data are
analyzed using slip vectors, microrotations, and the Nudged Elastic
Band method to determine the mechanisms leading to mixed
mobility trends with respect to temperature. Analysis indicates that
an unchanging series of mechanisms controls grain growth in these
boundaries, with the slowest mechanism controlling the mobility
trend at a given temperature. Size effects of the mobility are
considered using various simulation cell sizes.
ABSTRACTS THURSDAY PM1 - PLENARIES 89
THURSDAY PM1 PLENARY SESSION
A model of grain fragmentation and microtexture evolution during plastic deformation Sivasambu Mahesh Indian Institute of Technology Madras, Chennai, India.
Plastic deformation of polycrystals is accompanied by two interdependent phenomena: texture development, and substructure formation.
Together, these phenomena determine the state of plastic anisotropy of the polycrystal. For a given deformation path, the texture determines the
set of favorably oriented slip systems in the grains, while the substructure determines the critical resolved shear stresses thereof.
A polycrystal plasticity model for fcc materials, wherein the texture and substructure are evolved simultaneously, will be described. Much attention
will be paid to the physical principles governing the orientation and spacing of the dislocation walls, of which the substructure is comprised. It will
be shown that there are two substructural length scales, which must be handled separately: (1) the larger scale of elements such as deformation
bands, and shear bands, which span the grain, and (2) the smaller scale of elements such as cell blocks, dense dislocation walls, and microbands. It
will be shown that although minimization of the plastic power underlies the formation of both scales of substructure, velocity continuity conditions
are preserved across elements of (1), but not across (2). Efficient computational schemes to include both types of sub-structural elements into a
polycrystal plasticity code will be mentioned. Predicted plastic anisotropy of fcc polycrystals with and without the substructural information will be
compared.
The Evolution and Quantification of Preferred Crystallographic Orientations in Wrought Titanium Alloys Using Traditional and Emerging Technologies B Wynne1, M Thomas2. 1Department of Engineering Materials, The University of Sheffield, Mappin Street, Sheffield, S1 3JD. 2TIMET UK, PO Box 704, Birmingham, B6 7UR.
Over the past fifty years the aerospace industry has chosen wrought alpha/beta and near alpha Titanium alloys for rotating aero-engine
applications. These alloys are often produced via cast ingot formed through multiple iterations of thermo-mechanical “work” into a near-net shape
component comprising bi-modal microstructures with between 15-35% refined equiaxed primary alpha grains in a matrix of a lamellar alpha
transformation product. A number of studies by prominent authors have shown that the major features within these microstructures that
determine the alloys static and fatigue strength are not only alpha grain size, shape and morphology but also the size, shape and orientation of
clusters of similarly orientated alpha features know as macrozones or micro texture regions (MTR’s). As such, significant work is currently being
undertaken to quantify macrozones, investigate their evolution during processing and define their effect of component properties.
Electron Back Scatter Diffraction (EBSD) is commonly used within both industry and academic institutions to assess microtexture in various titanium
alloys and some relevant examples will be shared here. However, the destructive nature of sample preparation needed for EBSD and the time
needed to complete a representative level of analysis has prevented its wider use. A number of complimentary or alternative techniques have
recently been developed and will be elucidated here. The challenges associated with effective sampling of material at relevant stages through the
process route and the methods used to quantify and compare macrozones will be discussed and demonstrated.
ABSTRACTS THURSDAY PM1 - DEFORMATION 90
Symposium D: Deformation Textures Session: Modelling
Symposium Chairs:
Professor Chadwick Sinclair, Department of Materials Engineering, University of British Columbia
Professor Warren Poole, Department of Materials Engineering, University of British Columbia
Dr. Samantha Daly, Department of Mechanical Engineering, University of California, Santa Barbara
Measured resolved shear stresses and active slip systems in austenitic steel G. Winther1, N. Ytterdal Juul1 and J. Oddershede2 1Department of Mechanical Engineering, Technical University of Denmark, Kgs. Lyngby, Denmark. 2Xnovo Technology ApS, Køge, Denmark.
With the purpose of determining the critically stressed slip systems
in a tensile deformed austenitic stainless steel, the full stress tensor
is measured for 150 individual bulk grains using 3DXRD microscopy
at CHESS. The measured stress states are further compared to the
theoretical Bishop-Hill states. In the elastic regime, the resolved
shear stresses exhibit quite large variations between grains of
similar orientation. On average, however, the resolved shear
stresses agree well with the Schmid factors for uniaxial tension. In
the plastic regime at 1% elongation, about half of the grains were
close to a Bishop-Hill state. The orientation dependence of the
Bishop-Hill state was, however, not exactly as expected. The other
half of the grains was closer to the applied uniaxial stress, in
between two Bishop-Hill stress states, or in some cases none of
these. Comparison to finite-element crystal plasticity simulations
only qualitatively agree.
Comparison of measured lattice rotations of individual grains with crystal plasticity simulations N. Ytterdal Juul 1, J. Oddershede2 and G. Winther1 1Department of Mechanical Engineering, Technical University of Denmark, Kgs. Lyngby, Denmark. 2Xnovo Technology ApS, Køge, Denmark.
The lattice rotations of more than 300 grains in a 0.7x0.7x0.5 mm3
volume of a 316 stainless steel sample deformed in tension have
been monitored by 3DXRD microscopy at CHESS to 5% elongation.
The initial grain morphologies and microstructure were also mapped
out in high spatial resolution using a near-field detector. This map
serves as the input to finite-element based crystal plasticity
simulations approximating the modelled crystallographic
neighbourhood of individual grains closely. The experimental
rotations are compared to the model results, revealing a larger
spread of the experimental data. Representative grains are selected
for detailed studies to investigate this in more detail.
Texture Development in Two-Phase Mineral Aggregates: Modeling Plastic Deformation with Finite Element Methods E. Zepeda-Alarcon1 and M. Kasemer2 1University of California Berkeley, Berkeley, USA. 2Cornell University, Ithaca, USA.
Modeling plastic deformation in two-phase polycrystalline materials
comprised of phases with pronounced strength contrast is of
interest because of their abundance in the Earth and for specific
engineering applications. Large strength contrast between phases
and single crystal anisotropy is known to influence the development
of stress and strain heterogeneity within grains. Texture
development in these systems has a strong dependence on the
orientation distribution, and the development of misorientation
within each grain is dependent on their orientations and the
strengths of grains within the local grain neighborhood. The classical
Taylor theory and the more sophisticated self-consistent models are
successful in modeling average properties, but do not accurately
predict intragranular heterogeneity, and typically lead to more
pronounced textures than those which are experimentally observed.
In this study, the deformation response of a two-phase polycrystal
with a mixture of orthorhombic bridgmanite MgSiO3 and cubic
periclase (MgO) is simulated by means of a crystal plasticity finite
element framework. This material is significant because it composes
most of the Earths’ mantle and is important for understanding
geodynamic processes. Special attention is drawn to the evolution of
intragranular misorientation, and its dependence on the grain
neighborhood and strength contrast between the phases. It is found
that when the bridgmanite phase is 8 times harder than periclase,
periclase carries almost 70\% of the total plastic deformation of the
aggregate, and intragranular misorientation is larger in periclase
than in bridgmanite. Furthermore, interconnected soft grains exhibit
larger deformation rates and intragranular misorientations than soft
grains surrounded by predominantly hard grains. The opposite trend
is witnessed when inspecting the hard bridgmanite phase. The
development of this intragranular misorientation is responsible for
the weak texture development that has been experimentally
observed in this two-phase aggregate with a large strength contrast.
Statistical models for deformation texture prediction using vortex-type accommodation of local strain misfits P. Van Houtte1, B. Van Bael1 Q. Xie2 and M. Seefeldt1 1Department of Materials Engineering, KULeuven, Leuven, Belgium. 2 Oak Ridge National Lab, USA.
Many advanced models for deformation texture prediction make
use of crystal plasticity finite element or fast Fourier methods. They
manage to deal with strain heterogeneities at very small length
scales occurring for example in multiphase or nanostructured
materials. However, they demand a lot of calculation power, too
much for daily use as tools for computer aided
design/manufacturing of forming operations of massively produced
steel or aluminum sheet parts. So-called statistical models for
deformation texture and plastic anisotropy are still of interest in
such cases, as they are fast and can indeed be incorporated as
constitutive models in finite element simulations of metal forming
processes. Well known statistical models which are reasonably
accurate are the VPSC and ALAMEL model. The present work
ABSTRACTS THURSDAY PM1 - DEFORMATION 91
discusses an attempt to further improve the quality of the
predictions of the ALAMEL model by not only allowing local
deviations from homogeneous strain (as ALAMEL does), but also
taking the plastic accommodation of these misfits into account. This
is not done using an Eshelby-type approach but rather by assuming
the existence of local ‘vortices’ as those observed in flowing water.
The model will be briefly explained. Predicted ODFs of rolling
textures of one steel and one aluminum alloy will be compared with
those of older models as well as with experimental results.
[1] P. Van Houtte, S. Li, M. Seefeldt & L. Delannay (2005) Int. J. Plasticty 21, 589.
[2] Q. Xie, A. Van Bael, J. Sidor, J. Moerman, P. Van Houtte (2014) Acta Materialia, 69 175.
ABSTRACTS THURSDAY PM1 – DEFORMATION 92
Symposium D: Deformation Textures Session: Torsion
Symposium Chairs:
Professor Chadwick Sinclair, Department of Materials Engineering, University of British Columbia
Professor Warren Poole, Department of Materials Engineering, University of British Columbia
Dr. Samantha Daly, Department of Mechanical Engineering, University of California, Santa Barbara
Microstructural Engineering In Pearlitic Steel Wires A. Durgaprasada, S. Giria,b, S. Lenkab, S. Kundub, S. Chandrab, S.Mishrac, R. D. Dohertya,d and I. Samajdara aDepartment of Metallurgical Engineering and Materials Science, IIT Bombay, Mumbai – 400076, India. bResearch and Development Division, TATA Steel, Jamshedpur – 831 001, India. cDepartment of Mechanical Engineering, IIT Bombay, Mumbai – 400076, India. dDepartment of Materials Science and Engineering, Drexel University, Philadelphia, PA 19104
This study involved fully pearlitic wires of near eutectoid
composition. The original wire rod, of 5.5 mm diameter, was
subjected to seven stages of wire drawing (maximum strain of
~2.5). Microstructures and mechanical properties of both as
drawn (AD) and laboratory annealed (LA), re-austenitized and then
air-cooled to reform the pearlite structure, wires were investigated.
Morphological alignment (along the wire axis) of the LA pearlite
improved significantly (32% to 93%) as the wire diameter decreased.
This was enforced through a combination of crystallographic texture
and state of residual stress. The majority of the pearlite lamellae
appeared to align, in a 2-D analysis, with minimum elastic stiffness
(EMin under simple compression) for the ferrite (). 3-D
microstructures and measurements on coarse pearlite established
the pearlite crystallography and orientation dependence of the
pearlite growth. The LA grade offered excellent tensile strength
(from very low interlamellar spacing) and torsional ductility (from
the pearlite alignment). Absence of work hardening, on the other
hand, provided lower torsional yield than the traditional patenting-
wire drawing route.
Reciprocal effect of texture evolution and grain fragmentation during High Pressure Torsion processing S. Naghdy1, L. Kestens1,2 and P. Verleysen1 1Ghent University, Ghent, Belgium, Department of Electrical Energy, Metals, Mechanical Constructions and Systems. 2Delft University, Delft, The Netherlands, Department of materials science and engineering
The aim of this work was to examine the evolution of texture during
high pressure torsion (HPT) processing. Commercially pure
aluminum was subjected to monotonic HPT deformation at room
temperature. Microstructure and texture were studied by large area
EBSD scans. During processing, two distinct stages of microstructural
evolution were observed, a stage of grain fragmentation followed by
a saturation stage. In both stages, the global texture is characterized
by the typical shear components of face-centered cubic metals. It
was observed that a preferential fragmentation pattern occurs in
the first stage: orientations in the vicinity of ideal fibers became less
heavily fragmented while non-ideal orientations broke up more
severely. This phenomenon was linked with the lattice rotation
required to bring an initial orientation close to a stable one.
Although the texture weakened considerably during the
fragmentation stage, the texture index did not further decrease in
the saturation stage. The saturation of texture, grain refinement and
formation of microstructure are discussed in detail.
Texture gradient in extruded Mg-alloys versus extruded Mg-Al composites H.-G. Brokmeier1, S. Sanamar1, N. Chen1, X, Shi1, N. Al-Hamdany1, M. Z. Salih1, N. Schell2 1Inst. of Mat. Science and Engineering TU Clausthal, Clausthal-Zellerfeld, Germany.2Helmholtz-Zentrum Geesthacht, GEMS-Outstation DESY, Hamburg, Germany.
Crystallographic textures of bulk materials tend to have gradients for
example along cross sections of extrudates, sheets or semi-finished
products. This texture gradient can be related to the deformation
process itself, on the reduction rate per deformation pass and on
the friction conditions. Particularly, it is known from samples having
huge cross section like thick plates for ship or bridges, that strong
texture gradients exist [1]. The present investigation compares the
texture gradient of rectangular extruded Mg-alloys with Mg-Al
composites. Global texture analysis was carried out by neutrons
using the texture diffractometer TEX-2@FRG-1/Geesthacht-
Germany and texture gradients were measured by synchrotron
radiation at the high energy beamline HEMS@Petra III/Hamburg-
Germany. The global textures of Mg-alloys show typical variations of
known texture components, depending on the alloys and the
deformation process. In Mg-Al composites produced by commercial
Mg powder and commercial Al powder with mixtures of 60%Mg-
40%Al and 40%Mg and 60%Al the Mg part develops textures
components seen in Mg-rare earth alloys. Al develops the typical
deformation texture of Al. Due to the co-deformation texture
sharpness is reduced in composite material compared to pure
metals.
The texture gradients have been measured with a beam cross
section of 100 x 100 µm [2] and show strong differences for Mg-
alloys compared to Mg-Al composites. A surprising result was
obtained for the two-phased Mg - Al composite having a cross
section of 20 x 5 mm cross section. While the texture components in
Al are mostly the same over the cross section, Mg shows a quite
different behavior. In Al only the texture sharpness of the typical Al
deformation texture decreases from outside to inside, Mg losses the
plain strain texture symmetry. As already mentioned, commercial
pure Mg shows as main texture component the splitting of the
central pole in the basal pole figure (0002) in ± RD. These poles
twist, so that one pole moves to +TD and the other one to -TD with
increasing angle the closer the sample position was at the outside of
the 20mm length.
ABSTRACTS THURSDAY PM1 – DEFORMATION 93
[1] Z. Y. Zhong , H.-G. Brokmeier, E. Maawad & N. Schell (2015) IOP Conf. Ser.: Mater. Sci. Eng. 82, 012100.
[2] H.-G. Brokmeier, A. Günther, S. Yi, W. Ye, T. Lippmann & U. Garbe (2003) Adv. X-ray Analysis 46, 151.
Hierarchical data-driven models for texture evolution in advanced multiphase materials Marat I. Latypov1, Irene J. Beyerlein1, and Surya R. Kalidindi2 1University of California Santa Barbara, Santa Barbara, CA, USA. 2Georgia Institute of Technology, Atlanta, GA, USA
Modeling of engineering materials with hierarchical structure
requires multiscale approaches. Bridging across multiple length
scales in a computationally efficient fashion remains a great
challenge despite continuous improvements in the computational
power. In this talk, we will present our recent advances in the
development of an efficient data driven framework for multiscale
modeling of advanced multiphase materials. In focus will be
multiphase polycrystalline materials with consideration of
localization and homogenization problems at the length scales of
phases and polycrystalline aggregates as well as constitutive
behavior of individual crystals. Micromechanics at the phases scale
is tackled by microstructure-sensitive models calibrated to data
obtained by finite element simulations, whereas crystal plasticity
and texture evolution are addressed with the aid of an efficient
spectral database. It will be shown that the framework offers a
combination of accuracy and low computational cost and thereby
presents an important step towards fully coupled multiscale
modeling of engineering processes of advanced metallic materials
with hierarchical microstructures.
ABSTRACTS THURSDAY PM1 - TRANSFORMATIONS 94
Symposium T: Transformation Textures Symposium Chair:
Dr. Michael Roach, Biomedical Materials Science, University of Mississippi Medical Center
Formation of microtexture induced by β to α transformation in a metastable β Ti alloy Ke Hua1,2, Yudong Zhang1, Hongchao Kou2, Jinshan Li2, Weimin Gan3 and Claude Esling1 1Laboratoire d’ Etude des Microstructures et de Mecanique des Materiaux (LEM3), CNRS UMR 7239, Universite de Lorraine, 57045 Metz, France. 2State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, 710072 Xi’an, PR China.
3Helmholtz-Zentrum Geesthacht, Max-Planck-Straße 1, 21502 Geesthacht, Germany.
The mechanical properties of Ti alloys are intimately related to the
microstructure produced by the β to α phase transformation during
thermal or thermo-mechanical treatments. This phase
transformation is realized by a structure change from BCC β to HCP
α accompanied by a repartition of alloying elements. Microtextures
of the α phase are often present due to the selection of α variants
and have influences on the mechanical properties of the alloy. Thus,
knowledge on the formation mechanisms is of importance. Based on
this, a study was conducted, in the present work, on the selection of
variants in a metastable β Ti alloy under stress free transformation
condition. It is found that the α phase is in plate shape and related
with the β matrix by the Burgers orientation relationship (BOR).
Locally 3 BOR α variants interrelated by a 60° rotation around the
<11-20>α form a triangular structure. Close examination revealed
that nano-sized secondary α particles precipitate in the interface
area between each α plate and the surrounding β matrix. The
orientation of the secondary α particles is the same as that of one of
the other two α plates in the triangular structure. These secondary α
particles serve as nuclei for the formation of α plates with the same
orientation in the triangular structure and contribute to the
selection of variants to form local α texture. This work provides new
insights into the formation mechanisms of the microtexture (also
transformation texture) of metastable β Ti alloys under stress free
condition.
Variant selection in alpha/beta Ti alloy D. Solas1, S. Le Corre1, R. Forestier2 and F Brisset1
1Univ Paris Sud, ICMMO, CNRS, UMR 8182, F-91405 Orsay, France. 2ARDEM; Aubert & Duval 75 boulevard de la Liberation ; B.P.173, Pamiers Cedex, 09102, France
Mechanical properties of alpha/beta Ti alloys are improved through
complex thermomechanical treatments. The effects of beta forging
on microstructure and phase transformation are investigated for a
Ti-6246 alloy. Textures have been measured by neutron and X ray
diffraction. SEM/EBSD investigations have been used to characterize
the alpha phase precipitation.
After beta-forging, the microstructure is composed of clusters of
grains with <100> or <111> direction aligned with the forging
direction. During beta to alpha transformation, alpha orientation is
determined by the Burgers orientation relationship. One beta grain
generates up to twelve alpha orientations. After high deformation in
the beta domain, only 4 variants appear in the <100> grains,
whereas no variant selection is observed in the <111> grains.
Finally, the anisotropy of elastic properties of the alpha/beta
domains is calculated using a self-consistent approach. The elastic
properties of both phases are taken into account as well as the
different configurations of alpha variant selection.
Probabilistic methodology for analyzing and reconstructing parent microstructures from EBSD maps of transformation products Stephen Niezgoda1, Eric Payton2, Alex Brust1, and Vikas Sinha2 1The Ohio State University, Columbus OH, USA. 2Air Force Research Laboraotry, Dayton OH, USA.
The properties and performance of transformation microstructures
are often dependent on features of the prior microstructure, such as
texture or grain size, which have been obscured by the
transformation. Reconstruction of the parent is typically
mathematically ill-posed, as the forward transformation
Is often one-to-many; exhibiting multiple orientation variants or
transformation pathways. Point-to-point reconstruction techniques,
which rely on a pre-supposed orientation relationship, may not be
robust to noise or deviations from ideal conditions. Here we present
a probabilistic approach to quantify
The uncertainty in the orientation relationship and noise due to
measurement resolution, variation in parent orientation, and sample
preparation. The reconstruction is formulated as a global
optimization where the target is to minimize the probability of
misindexed points or equivalently to find the parent microstructure
which was most likely to generate the observed transformed
dataset. While the approach is material agnostic and will be
demonstrated on prior-austenite grain reconstruction in carbon
steels.
Orientation dependent spheroidization response and α-phase texture evolution during sub β-transus annealing of Ti-6Al-4V alloy Shibayan Roya,b, Satyam Suwasb aMaterials Science Centre, Indian Institute of Technology, Kharagpur, India. bDepartment of Materials Engineering, Indian Institute of Science, Bangalore, India
Spheroidization response of the constituent α-colonies in a warm-
rolled Ti-6Al-4V alloy is known to differ significantly during sub β-
transus static annealing. In this communication, the same has been
examined for the first time from an orientation perspective by
coupling slip activation, boundary formation and interfacial energy
anisotropy of individual α-colonies. The orientation of the α-colonies
with reference to the loading directions dictates the nature of slip
activation (single versus multiple slip; basal or prism <a> slip plus
pyramidal <c+a> slip) during (α+β)-rolling in the first place. During
subsequent static (α+β)-annealing, this factor initially translates into
the relative ease of boundary splitting and thermal grooving for
ABSTRACTS THURSDAY PM1 - TRANSFORMATIONS 95
them. Formation of longitudinal boundaries then set the order of
spheroidization for diffusion based coarsening processes during long
term annealing. Anisotropy in interfacial energy as a consequence of
loss of coherency during prior deformation creates further
orientation dependency in the spheroidization sequence. As a
concomitant effect, sub β-transus annealing results in significant
weakening of basal fibre (ND║<0001>) and complementary
strengthening of prism fibre (RD║<10 0>) from prior-rolled texture.
This modification is conjugated to the orientation dependent
spheroidization of primary α-phase (αp) which makes a distinction
between their relative contribution to these texture fibres.
Orientations proximity between secondary α (αs) and stable αp-
phases further contributes to this texture transition.
ABSTRACTS THURSDAY PM1 - ENGINEERING 96
Symposium A: Texture and Anisotropy in Advanced Engineering Processes and Materials Session: Advanced Processing – Friction Stir Welding
Symposium Chairs:
Professor Tracy Nelson, Department of Mechanical Engineering, Brigham Young University
Dr. Ashley Spear, Department of Mechanical Engineering, University of Utah
Texture evolution in flash and weld zone of friction welded 718 superalloy T.W. Nelson, F.C. Liu, and, C. Brown Department of Mechanical Engineering, Brigham Young University, Provo, UT 84602, USA
During rotary friction welding, the friction and plastic deformation
causes softening in the two pieces near the weld interface. As the
material softens, material is gradually extruded or expelled away
from the interface under an axial force, forming flashes. Texture
analysis of the flash and weld zone of friction welded 718 superalloy
is beneficial to the understanding of the deformation and material
flow during welding. The texture was firstly measured on a post-
welded sample which is produced through a standard welding
procedure. The B component {112}<110> was detected in the weld
zone. The deformation texture was concealed in the flash as a result
of significant grain coarsening. In order to investigate the grain
structure, material flow and texture evolution during deformation, a
water quench was applied during the welding. In the quenched
samples, stronger B component {112}<110> was detected in both
the flash and weld zone. The shear direction of the B component can
be used an indicator of the local material flow direction.
Using EBSD in the characterization of heterogeneous microstructure created in high speed friction stir welded aluminum alloy Jingyi Zhang1, Cory Palmieri1, Piyush Upadhyay2, Yuri Hovanski3, and David P. Field1 1Washington State University, Pullman, USA. 2Pacific Northwest National Laboratory, Richland, USA. 3Brigham Young University, Provo, USA.
EBSD provides valuable information about the deformation history
of materials. The input data of EBSD are collected on a
microstructure level, making it the ideal approach for analysis of
materials with large spatial texture gradient such as friction stir
welded (FSW) structures. In this study we explore the various
possibilities and benefits of using EBSD technique and texture
analysis to characterize the formation and properties of aluminum
high-speed friction stir welds. The deformation texture present in
the weld structure is calculated on microstructure scale and used to
determine the local deformation mode and deformation direction.
This approach can generate the material flow field inside the nugget
zone and TMAZ of FSW, and help to determine the stress state in the
fusion zone underneath the nugget zone. Other characterizations
including the grain boundary misorientation distribution and GNDs
density are also made from EBSD data to describe the wide variety
of microstructure across the weld affected volume.
Friction Stir Weld Textures and their Implications on 3D Material Flow R.W. Fonda, K.E. Knipling and D.J. Rowenhorst U.S. Naval Research Laboratory, Washington, DC, USA.
The deformation textures produced by friction stir welding can be
used to reveal the three-dimensional material flow that was
occurring during welding. Friction stir welding generates
deformation textures that vary in orientation in a complex manner
across the width and through the thickness of the deposited weld.
These orientation variations correspond to changes in the local
shear deformation frame of reference at the time of deposition, and
can be approximated geometrically using the fractional distance
across the weld and the effective tool surface inclination at that
depth [1]. Experimentally observed friction stir weld textures
generally follow these predictions, but also exhibit deviations that
signify variations from the expected local shear deformation
orientation, and thus local variations in the material flow direction.
These deviations have been quantified across the weld at three
depths to reveal the three-dimensional material flow that occurs
during friction stir welding.
[1] R.W. Fonda, K.E. Knipling, & D.J. Rowenhorst (2014) JOM 66, 149.
Texture evolution during friction stir welding of austenite stainless steel F.C. Liu, and T.W. Nelson, M.P. Miles Department of Mechanical Engineering, Brigham Young University, Provo, UT 84602, USA
The texture evolution during the whole process of friction stir
welding (FSW) of 304L stainless steel are clarified. As the base
material approached the probe, grains were compressed, evolving
to fine equiaxed grains mainly through discontinue dynamic
recrystallization (DDRX). As these fine grains rotated around the
probe, The B component {112}<110> with its shear direction being
consisted with the local probe rotation was developed. The shear
plan of B component maintained approximately 30 deg away from
the probe profile. After the material was deposited behind the
probe, deformation caused by tool shoulder weakened the B
component. The B component evolved to a C component
{001}<110> in the region whose deformation was significantly affect
by the shoulder. For the samples welded at reduced welding power,
the texture was less effected by the shoulder and the B component
{112}<110> was remained in the weld zone.
ABSTRACTS THURSDAY PM1 - BOUNDARIES 97
Symposium B: Misorientation Textures at Grain Boundaries and Interfaces Symposium Chairs:
Dr. Eric Homer, Department of Mechanical Engineering, Brigham Young University
Dr. Srikanth Patala, Department of Materials Science and Engineering, North Carolina State University
Role of CSL Boundaries During Cold Rolling and Annealing of an Interstitial Free Steel Rajib Saha1, R. K. Ray2 and A. D. Rollett3 1Research & Development Division, Tata Steel, Jamshedpur, India. 2MN Dastur School of Materials Science and Engineering, IIEST, Kolkata, India. 3Materials Science & Engineering, Carnegie Mellon University (CMU) USA
Changes in the texture and CSL boundary distribution during cold
rolling and annealing of a commercial grade Interstitial Free (IF) steel
have been investigated. The CSL boundaries associated with
particular texture types were quantified using the OIM™ Texture
Analysis software. This was done for both individual components of
texture, as well as for groups of components belonging to the γ
(ND//<111>) and the α (RD//<110>) fibers. The total lengths as well
as number fractions of various CSL boundaries related to different
texture types were then determined. The results clearly show that
each particular type of texture (individual component or a group of
components) is associated with a particular CSL grain boundary
distribution (CGBD). The histograms of CSL number fraction and
length fraction as a function of CSL type are similar in shape. The
density of Σ3 boundaries is the highest amongst all the CSL
boundaries for all the textural conditions. In general, the total CSL
fraction increases from the cold worked to the recrystallization
state, although the total CSL fraction decreases during grain growth.
Generally, the number fraction of CSL boundaries is higher in case of
the 110//RD texture grains as compared to the 111//ND oriented
grains. During grain growth, however, the 111//ND related CSL
boundaries increase at the expense of the 110//RD related CSL
fraction. An attempt has been made to explain the above
observations with the help of texture and microstructure data.
The Representation of Grain Boundary Texture Using Hyperspherical Harmonics Srikanth Patala1, Jeremy K. Mason2 1North Carolina State University, Raleigh, USA. 2University of California, Davis, USA.
The statistical distribution of different grain boundary types play an
important role in governing the mechanical and function properties
of polycrystalline materials. However, even for simple
microstructures, the capability of representing the distributions of
GB character, as a function of the five macroscopic degrees of
freedom, has not been established. As the GB character distributions
directly influence the interfacial network connectivity, developing a
framework for quantifying the statistics in the five-parameter space
is a crucial missing step in the inverse-design of interface-dominated
phenomena in polycrystalline systems. In this talk, I will present
symmetrized functions, using the familiar hyperspherical harmonics,
for representing grain boundary texture in the complete five-
parameter space. The basis functions will also allow for the
quantification of interfacial statistics in experimental
microstructures and the interpolation of structure-property
relationships of grain boundaries.
Grain orientation statistics of grain-clusters and the propensity of multiple-twinning during grain boundary engineering Shuang Xia, Tingguang Liu, Qin Bai, and Bangxin Zhou School of Materials Science and Engineering, Shanghai University, Shanghai 200072, China
Large grain-cluster or so-called twin-related domain is a typical
characteristic of the grain boundary (GB) engineered microstructure.
Grain-cluster is formed via numerous twinning operations starting
from single nucleus, and the process is referred to as multiple-
twinning. This work investigated the orientation diversity within
grain-clusters and the twinning ordering of multiple-twinning based
on the statistics of grain-orientations in 30 large-sized grain-clusters
from GB-engineered Ni-based alloy 690. The statistics show that the
grain-cluster apparently has several dominant orientations. A few
dominant orientations occupy most area and most grains in a grain-
cluster. Moreover, most misorientations between these dominant
orientations are of low-order ∑3n-type (n=1, 2), and the 4 sub-
dominant orientations are twinning variants of the first-dominant
orientation in most cases. These statistical characteristics of grain-
clusters reflect the general behavior of multiple-twinning: back-and-
forth pattern and preferential orientations. The twinning operations
produce not only higher (forward) but also lower (backward)
generation orientations, and the backward probability is higher than
the forward. The multiple-twinning shows a propensity to form or
access to a few preferential orientations, and results in the
formation of dominant orientations of the formed grain-cluster.
[1] T.G. Liu, S. Xia, B.S. Wang, Q. Bai, B.X. Zhou & C. Su, (2016) Mater. Des. 112, 442
ABSTRACTS THURSDAY PM2 - DEFORMATION 98
Symposium D: Deformation Textures Session: Modelling
Symposium Chairs:
Professor Chadwick Sinclair, Department of Materials Engineering, University of British Columbia
Professor Warren Poole, Department of Materials Engineering, University of British Columbia
Dr. Samantha Daly, Department of Mechanical Engineering, University of California, Santa Barbara
Revealing deformation heterogeneity from texture modeling Laszlo S. Toth Laboratory of Excellence on Design of Alloy Metals for low-mAss Structures (DAMAS), Université de Lorraine, Metz, France, Laboratoire d’Etude des Microstructures et de Mécanique des Matériaux (LEM3), UMR7239, CNRS / Université de Lorraine, F-57045 Metz, France
It is well known in experiments and also in modeling that
crystallographic texture is very sensitive to the mechanisms acting
during its formation. It is therefore suitable to examine all
phenomena that can change the crystallographic orientation
(dislocation slip, twinning, grain boundary sliding, recrystallization,
phase changes, etc…). Moreover, the texture being three
dimensional, it is not an easy task to reproduce it by modeling.
Therefore, successful simulations can provide strong evidences for
the existence of the mechanisms and for their magnitudes.
The present work aims to reveal the deformation inhomogeneities
that can exist between neighboring grains of the polycrystal. The
work reports about experiments as well as simulations in various
deformation paths and on different materials concerning the
evolution of the crystallographic texture and the density of
geometrically necessary dislocations (GNDs). The viscoplastic self-
consistent model was employed for reproducing the texture
evolutions. The major findings are:
1. In large and medium grain sized polycrystals the
deformation can be very heterogeneous, while grains of a
polycrystal composed of nano-sized grains deform very
similarly (Taylor-mode).
2. The GND density is a signature of strain heterogeneity and
the experiments confirm the above finding for the
deformation tending towards Taylor as the grain size
decreases.
3. Partial slip becomes a relevant deformation mechanism as
grain size decreases.
Acknowledgments
This research work was carried out in collaboration involving: Prof.
Werner Skrotzki, Technical University, Germany, Dresden, Dr.
Chengfan Gu, RMIT University, Melbourne, Prof. Tamas Ungar,
Eotvos University, Hungary, Prof. Irene Beyerlein, University of
California, Santa Barbara, Prof. Mark Hoffman, UNSW, Sydney,
Australia, Dr. Arnaud Pougis, SNECMA, Paris, France, Dr. Benoit
Beausir – Dr. Jean-Jacques Fundenberger – Dr. Yudong Zhang –
Lorraine University, Metz, France.
This work was supported by the French State through the program
"Investment in the future" operated by the National Research
Agency (ANR) and referenced by ANR-11-LABX-0008-01 (LabEx
DAMAS).
Texture evolution in Al alloys: crystal plasticity and continuum mechanics based modelling strategies Jurij Sidor Savaria Institute of Technology, Eötvös Loránd University (ELTE), Károlyi Gáspár tér 4, 9700 Szombathely, Hungary
Material’s flow during deformation is discussed by means of well-
established crystal plasticity (CP) approaches and principles of
continuum mechanics. Investigation of material’s behavior by finite
element models (FEM) excludes the mesoscopic transformation
which accounts for evolution of microstructure with characteristic
texture. Contrarily, Taylor-type crystal plasticity homogenization
models, dealing with partitioning of macroscopic load in a
polycrystalline aggregate, are not capable of explaining the effect of
various technological parameters on deformation flow. This
contribution provides a brief overview on modelling the
deformation textures by combining both CP and FEM approaches
and also discusses the effective strategies employed in texture
simulations. The effect of grain interaction phenomena on the
quality of texture prediction is revealed. With the help of CP and
FEM simulations, it is shown how microstructural heterogeneities
might influence the evolution of recrystallization and plastic strain
ratio in aluminum alloys.
Crystal plasticity simulations of rolling texture evolution in two phase tungsten heavy alloy Mirtunjay Kumar, N. P. Gurao, Anish Upadhyaya Indian Institute of Technology Kanpur, Kanpur, India
Evolution of texture and microstructure during rolling of two phase
tungsten heavy alloy (WHA) was investigated using bulk texture
measurement, electron backscatter diffraction and X-ray line profile
analysis. The experimental results showed the presence of
characteristic alpha <110> rolling direction and gamma fibre {111}
parallel to the ND plane in the 90% rolled WHA sample with the
gamma fibre being stronger than the alpha fibre. Evolution of
misorientation and orientation gradients in the body centre cubic
tungsten and face centre cubic Fe-Ni-W solid solution phase
indicated strain partitioning between the hard tungsten and soft Fe-
Ni matrix. Different crystal plasticity models like the in-house
developed full and relaxed constraint Taylor model and LAMEL and
ALAMEL model, grain interaction model as well as existing
viscoplastic self-consistent and crystal plasticity finite element
model. A comparison of the experimental texture with the simulated
texture obtained from different models will be presented with a
detailed discussion on the advantages and disadvantages of
different models. A perspective on the suitability of different models
ABSTRACTS THURSDAY PM2 - DEFORMATION 99
for predicting the evolution of deformation texture in WHAs will be
presented.
Intergranular interactions of metals during deformation and corresponding prediction of deformation textures W. Mao1,2 1Inner Mongolia University of Science and Technology, Baotou, China. 2University of Science and Technology Beijing, Beijing, China.
Most current theories and models for plastic deformation of
polycrystalline metals are based on the Taylor principles and some
modifications whereas the strain equilibrium between deformation
grains are reached obviously. However, the issue on stress
equilibrium has not been satisfactorily resolved yet. Therefore, the
deformation behaviors described by the theories are more or less
different from those of the grains in polycrystalline metals. The very
simple reaction stress model proposed emphasizes mechanical
interactions between grains, and both of the stress and strain
equilibria are obtained by activations of penetrating and non-
penetrating slips. The rolling texture simulations under the model
predict the same textures indicated by Taylor theory both in bcc and
fcc metals.
It is indicated that reaction stresses calculated between grains could
not be fully effective on evolution of grain orientations during rolling
of aluminum alloys and need to be relaxed, whereas brass texture
will be predicted by a fully relaxation of the reaction stresses.
Different reaction shear stresses may reduce brass texture and
promote S, Taylor texture or even copper texture instead of Taylor
texture. The β-fiber by high rolling reduction is located in the
orientation area, where the Schmid factors of activated slip systems
are sufficiently high and the brass shear strain is kept relatively low.
Different detailed engineering conditions have to be included in
deformation simulations if the deformation textures of industrial
products need to be predicted. The introduced reaction stress
principles, based on solid mechanical background, open theoretically
a new field of vision to consider deformation behaviors of
polycrystalline materials. Consequently, the Taylor principles
become no longer absolutely necessary.
ABSTRACTS THURSDAY PM2 – DEFORMATION 100
Symposium D: Deformation Textures Session: Damage and Fracture
Symposium Chairs:
Professor Chadwick Sinclair, Department of Materials Engineering, University of British Columbia
Professor Warren Poole, Department of Materials Engineering, University of British Columbia
Dr. Samantha Daly, Department of Mechanical Engineering, University of California, Santa Barbara
Mechanical damage evaluation by using EBSD measurement Seiichi SUZUKI1, Masayuki KAMAYA2, Keiji KUBUSHIRO3 and Toshihiro OHTANI4 1TSL Solutions KK, Sagamihara, Kanagawa, Japan. 2Institute of Nuclear Safety System, Inc.64 Sata, Mihama-cho, Fukui 919-1205, Japan. 3IHI Corporation, 1, Shin-nakahara-cho, Isogo-ku, Yokohama 235-8501, Japan. 4Shonan Institute of Technology, 1-1-25, Tsujidonishikaigan, Fujisawa-shi, Kanagawa 251-8511, Japan
Estimation of the remaining life time of turbine blade used under
high temperature environment is very important in industries.
Major cause to degrade these mechanical parts, which is expressed
as mechanical damage, are creep deformation. If the remaining life
time of these mechanical parts can be assessed by observing their
micro structure changes, it will offer big advantages for maintenance
of the systems using these parts. This research work was
performed to find some good method to evaluate the mechanical
damage by observing microstructure changes during creep
deformation.
8 tensile rod specimens of SUS316 were prepared. Creep test had
been done by using these specimen under the temperature of
700deg. C with 100MPa load. Creep test were continued for 0.0,
268, 489, 507, 528, 562, 584 and 694 hours, and resulted in tensile
elongation of 0.0, 7.37, 14.2, 21.6, 24.9, 18.4, 28.0 and 44.6%
respectively. The specimens were cut along with the center axis
which is same as tensile direction and polished for EBSD
observation. EBSD observation was done at continuous 3 areas with
scan size of 200x200m and step size 0.5m, then they were
merged into one date of 580x190 m.
It was observed that (111) plane normal direction became aligned
with tensile direction along with increase of deformation.
Misorientation maps such as KAM (Kernel Average Orientation) and
GOS (Grain Orientation Spread) were examined and the values of
both parameters increased as increase of deformation. But KAM
maps depended seriously on the step size and it was found that GOS
showed much more stable results of almost proportional relation to
the level of deformation. It was also found that the boundaries’
characters were changed along with the deformation. The original
SUS316 specimen had a lot of twin boundaries. But these twin
boundaries were decreased and low angle boundaries of less than 5
degrees increased very much during deformation. The ratio of twin
boundary against low angle boundaries were observed to decrease
well proportional to the level of the deformation. The decrease of
twin boundary was mainly caused by deviating from the condition of
plane matching of K1 planes [(111) planes of both side of the twin
boundary should be parallel] which tolerance was set to 1degree.
So the ratio of twin boundaries with K1 plans matched and without
K1 planes matched decreased well proportional to the degrees of
deformation up to around 15%.
As results of this series of experiments, it can be possible to estimate
the remaining life time of high temperature material by observing its
microstructure changes such as KAM, GOS and twin boundary
characters. Further test may be necessary to confirm these results
for industrial application.
This work was originally done as a basic research experiment of
‘Mechanical Damage Assessment WG’ under the High Temperature
Material Committee of the Society of Materials Science of Japan. [1]
[1] M. Kamaya, et.al (2016) Mechanical Engineering Journal, Vol3, No3
Damage initiation mechanisms under static and dynamic loading conditions in bainitic steels B. Shakerifard1, J.G. Lopez2 and L.A.I. Kestens3 1,3Technical University of Delft, Delft, Netherlands. 2Materials Innovation Institute, Delft, Netherlands.
The goal of this research is to optimize the microstructure of a
bainitic advanced high-strength steel in order to improve cold
formability and edge-cracking behavior. This will enable enhanced
energy absorption due to higher yield strength, higher elongation
and favorable crash folding behavior because of improved bending
properties. To approach this goal, two batches of bainitic steel with
low and high silicon contents were produced. Several annealing
treatments were carried out to provide a bainitic matrix with various
morphologies of second phase constituents (martensite, retained
austenite and carbides). Static and dynamic mechanical tests were
performed in order to evaluate the mechanical response of the
materials to the low and high strain rate deformations, respectively.
The microstructures and their textures were analyzed quantitatively
by X-ray diffraction and orientation contrast microscopy. The
correlation between microstructural features and mechanical
properties has been studied. In addition, the damage initiation
mechanism under static and dynamic loading conditions were
studied and compared.
Evaluating the Role of Texture on Surface Roughness Induced Stress Concentrations C. A. Kantzos1, R. W. Cunningham1, and A. D. Rollett1 1Carnegie Mellon University, Pittsburgh, USA.
Stress concentrations caused by geometric inhomogeneities on the
surface of a material are well known to have a negative impact on
mechanical performance, especially by promoting fatigue crack
initiation. Some empirical and mechanical models have been
developed to relate surface geometry to mechanical properties, but
very little has been done to incorporate microstructural texture,
especially local surface texture, into such models. Herein an FFT-
ABSTRACTS THURSDAY PM2 – DEFORMATION 101
based crystal plasticity model is used to evaluate how texture,
coupled with surface roughness, can increase stress concentrations
and localized slip activity. Based on experimental observations,
simulated 3D surfaces with varying degrees of texture were
generated, and the response to different loading conditions were
analyzed using extreme value statistics. The relevance of these
results to fatigue life, and the importance of texture considerations
are discussed.
EBSD Observations of Fatigue Crack Propagation in Ni Alloy S. I. Wright1, M. M. Nowell1, R. de Kloe2 1EDAX, Draper, UT, USA. 2EDAX, Tilburg, The Netherlands
Electron Backscatter Diffraction (EBSD) observations were made on
a Ni alloy containing a fatigue crack. The crack was observed to be
both transgranular and intergranular. From the EBSD observations
on the two-dimensional plane it was found that the crack
propagated primarily following (111) plane traces. Analysis of the
plane traces was conducted to try and gain some understanding of
the local dynamics governing the propagation of the crack through
the microstructure.
ABSTRACTS THURSDAY PM2 - NUMERICS 102
Symposium N: Mathematical, Numerical and Statistical Methods of Texture Analysis Symposium Chair:
Dr. Oliver Johnson, Department of Mechanical Engineering, Brigham Young University
Parameterization of rotations in reference frames with redundant crystallographic axes A. Morawiec Polish Academy of Sciences, Institute of Metallurgy and Materials Science, Reymonta 25, 30-059, Krakow, Poland,
Parameterizations of orientations or rotations in three-dimensional
space are fundamental for description of crystallographic textures.
Such parameterizations (e.g., Rodrigues parameters) are usually
specified using orthonormal coordinate systems, whereas bases of
crystal lattices are generally non-orthogonal. In the case of crystals
with hexagonal or rhombohedral lattices, the reference frames
involve redundant crystallographic axes. Hence, a question arises
about feasibility of the generalization of the rotation
parameterizations to such frames. We will present a method of
extending the definition of Rodrigues parameters so they can be
directly linked to non-Cartesian bases of crystals. The new Rodrigues
parameters are contra- or covariant components of vectors specified
with respect to exactly the same lattice basis as atomic positions in a
unit cell. The generalized formalism allows for using redundant
crystallographic axes. Also, the orientation matrices can be
represented in such frames. The formulas for rotation composition
and the relationship between the rotation matrices and Rodrigues
parameters are similar to those in the Cartesian case, but they more
general: calculations can be performed with an arbitrary metric
tensor of the crystal lattice. The Rodrigues parameterization in non-
Cartesian coordinate frames is convenient for crystallographic
applications because the generalized parameters are directly related
to indices of rotation-invariant lattice directions and to Miller indices
of rotation-invariant lattice planes. In the case of in the hexagonal
and rhombohedral lattices, the redundant axes are used to account
for lattice symmetry, but one may use such axes for other reasons;
they can be useful for handling arbitrary symmetries, in particular,
symmetries of physical processes. E.g., in description of orientation
changes during plastic deformation, the frames can be chosen based
on characteristic directions and/or planes of slip or twinning
systems.
Systematic bias effects on phase fraction measurement due to texture A. Creuziger, C. Calhoun, W. Poling and T. Gnäupel-Herold National Institute of Standards and Technology, Gaithersburg, MD USA
Most advanced high strength steel alloys contain multiple phases,
each of which can have its own crystallographic texture. Accurate
measurement of the phase fractions via diffraction techniques
remains a challenge for many reasons. In particular, accounting for
texture remains elusive in current standards and practices. Many
methods have been proposed to deal with texture, such as use of
multiple peaks and/or additional tilt and rotation. However, a
systematic examination of these methods for bias errors due to
texture remains outstanding.
The present study serves as a first step in assessing the accuracy of
various proposed diffraction techniques through numerical
investigation of texture effects on simulated diffraction
measurements. The authors explored a two-phase system with fixed
phase fractions of 0.25 austenite and 0.75 ferrite. Synthetic textures
were computed, and for each generated texture, diffraction
intensities were computed for different diffraction methods. It was
seen that no methods had significant bias in the phase fraction value
for a random texture, but as texture increased, bias errors increased.
For a single sample orientation, using two austenite and two ferrite
peak pairs, calculated phase fractions of austenite ranged from 0.08
to 0.68 for a sample generated using a phase fraction of 0.25.
Increasing the number of considered peaks decreased the spread,
but apparent phase fractions still ranged from 0.18 to 0.35.
Simultaneous tilt and rotation yielded a comparable range of values.
However, if a hexagonal grid of pole figure space was used,
drastically lower bias errors were observed.
Comparison of Representative Volume Elements for Grain Boundary Networks and Textures T.R. Critchfield1, O.K. Johnson Brigham Young University, Provo, USA.
The use of representative volume elements in simulation of
polycrystalline microstructures facilitates a balance between
accuracy and computational efficiency. A representative volume
element (RVE) is the smallest sample size that accurately represents
the microstructure, in the context of the material property being
observed. The required size of an RVE has been determined for
texture-sensitive properties, but these findings have not addressed
the influence of the grain boundary network. We present findings on
appropriate RVEs for grain boundary networks in a diverse set of
microstructures and compare these to the required RVE for texture
in the same microstructures. These results will allow researchers to
accurately simulate and model grain boundary networks in a
computationally efficient manner and offer further insight to the
underlying influence of short- and long-range correlations on RVE
size.
Quantification of Uncertainties in Pole Figure Analysis S.K. Sridhar and A.D. Rollett Carnegie Mellon Univ., Pittsburgh, USA.
The effects of texture on Superelastic Effect (SE) and Shape Memory
Effect (SME) of Nickel Titanium (NiTi) have been extensively studied.
The experimental techniques to measure texture usually include
diffraction techniques like X-ray and neutron diffraction or
Orientation Image Mapping (OIM) techniques such as Electron Back
Scatter Diffraction (EBSD). However, EBSD is a surface based
technique and sample preparation is very demanding. EBSD is
challenging for NiTi samples because of their sensitivity to
mechanical surface deformation, especially when they are already
heavily cold worked. Therefore, the best method to get texture data
is using diffraction techniques. However, since lab diffraction
ABSTRACTS THURSDAY PM2 - NUMERICS 103
techniques such as X-ray Diffraction (XRD) typically measure
incomplete pole figures, it is essential to correct for this using
mathematical methods and estimate numerically the Orientation
Distribution Function (ODF). Moreover, there exist several ways to
estimate ODF from raw experimental Pole Figures (PFs). This further
leads to uncertainties in the interpretation of texture especially
when robust estimates of the volume fractions of the various
texture components are needed. This work organizes the calculation
of ODFs and quantification of uncertainties that arise depending on
the method chosen. The overall aim is to improve standards for
comparing texture among different samples.
ABSTRACTS THURSDAY PM2 - ENGINEERING 104
Symposium A: Texture and Anisotropy in Advanced Engineering Processes and Materials Session: Advanced Processing – Asymmetric Rolling
Symposium Chairs:
Professor Tracy Nelson, Department of Mechanical Engineering, Brigham Young University
Dr. Ashley Spear, Department of Mechanical Engineering, University of Utah
Experimental and Numeric Analysis of Strain and Texture of Asymmetric Rolled AA1050 Aluminum B. D. Zanchetta1, F. S. Nascimento2, A. M. Kliauga2, J. B. Rupert3, R. E. Bolmaro 4 1Universidade Federal de São Carlos, CCTS, Sorocaba, Brazil. 2Universidade Federal de São Carlos, Department of Materials Engineering, São Carlos, Brazil. 3Universidade Federal de São Carlos, Department of Mechanical Engineering, São Carlos, Brazil. 4Instutituto de Fisica de Rosario,Universidade Nacional de Rosario, Rosario, Argentina.
The asymmetrical rolling (AR) increases the shear strain during
deformation by changing the speed ratio between the superior the
inferior rolls. This will modify the texture of the deformed material
and induce greater grain refinement [1]. It also modifies the
recrystallization textures and thus alter the plastic anisotropy of
rolling sheets [2]. In this work, we quantified the equivalent
deformation and the induced percentage of shear of a AA1050
aluminum at speed ratios of 1.5 and 2.0 and thickness reduction per
pass of 10% and 5% up to an equivalent deformation of 1.4. The
experimental results were compared with the numerical simulation
using DEFORM V10. The crystallographic orientation was measured
by x-ray diffraction at the samples middle plane after each pass. The
initial sample had a recrystallization texture with a clear cube
texture. The distribution of shear, compression and rigid body
rotation was obtained from the finite element simulation. Most of
the shear components were concentrated at the sub surface planes,
closer to the rolls; and, at the samples middle plane the rigid body
rotation was the predominant strain component. A clear difference
in texture between surface and center was measured at an
equivalent deformation of 1.0. Consequently, the measured texture
for the initial rolling passes showed only a progressive rotation of
the texture components, whereas the subsurface region presented
shear components. Only after the final reduction steps shear
components could be identified at the middle plane. Increasing the
tangential speed ratio yielded higher shear strains but the effect of
reducing the reduction step was much more pronounced.
[1] G. Angella, B. EsfandiarJahromi, M. Vedani, (2013) Mat. Sci. Eng. A 559, 742.
[2] S. Tamimi, J.P. Correia, A.B. Lopes, S. Ahzi, F. Barlat, J.J. Gracio (2014) Mat. Sci. Eng. A 603, 150.
Texture and microstructure development in warm asymmetric rolled extra low carbon steel Satyaveer S Dhinwal and Peter D Hodgson Institute for Frontier Materials (IFM), Deakin University, Geelong, Australia
It has been noted that the metal processing based on shear
deformation exhibits enhanced grain refinement. Such metal
processing methods are also an alternate to tailor the deformation
texture of extruded bars and flat rolled sheets for some of their
structural and functional applications. Among them, rolling with
imposed asymmetric condition has been considered comparatively
more viable option to introduce through thickness shear effect in
continuous sheet manufacturing. It is because of the easy
implementation in conventional rolling mill and its ability to rotate
conventional rolling texture up to the preferred location of ideal
shear texture in Euler space.
The effect of asymmetric condition in warm rolling and its
consequences on recrystallization behavior is less investigated topic
as compared to the rolling in ambient condition. In the present
study, extra low carbon steel was warm rolled in between 250°C and
700°C and asymmetric conditions were imposed by changing roll
diameters ratio from 1:1 to 1:2 while having thickness reductions
per pass (TRPP) of 50% and 75%. It was observed that at lower warm
temperatures, the mid thickness regime of longitudinal
(perpendicular to the transverse direction) plane of a rolled sheet
shows rise in the fraction of orientation splitting and band formation
as the roll diameters ratio increases for a given TRPP. However, in
higher warm temperatures, the rate by which recrystallizing grain
forms in the vicinity of original grain bands and increase in their
fraction become significant in same asymmetric conditions of the
rolling.
Microstructural analysis with increase in the roll diameters ratio
reveals that Goss {110}<001> and D {112}<11-2> orientations of
shear texture are in strong majority as compared to any other
preferred orientations of a symmetric (1:1) case for a given area
fraction in the mid thickness of a rolled sheet. While, examination of
the grains which recrystallized during rolling shows the dominance
of Goss and D orientations along with noticeable presence of α fiber
<110> orientations of symmetric rolling.
It has been concluded from the present study that the mid thickness
regime of a rolled sheet can also form preferred orientations of
shear texture in majority as compared to the conventional rolling
texture. Formation of such shear texture orientations in warm
asymmetric rolled condition also affects the magnetization behavior
of thin laminates.
Modification of Texture and Microstructure of Polycrystalline Copper after Asymmetric Rolling A. Uniwersał1, M. Wróbel1, K. Wierzbanowski2, M. Wroński2, S. Wroński2, I. Kalemba-Rec1, T. Sak3 and B. Bacroix4 1AGH University of Science and Technology, Faculty of Metals Engineering and Industrial Computer Science, 30-059 Kraków, Poland. 2AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, 30-059 Kraków, Poland. 3AGH University of Science and Technology, Faculty of Non-Ferrous Metals, 30-059 Kraków, Poland. 4LSPM-CNRS Université Paris 13, 93 430 Villetaneuse, France
ABSTRACTS THURSDAY PM2 - ENGINEERING 105
Asymmetric rolling process is a subject of many research works in
the last years. In this kind of rolling some technological parameters
can be modified, like: normal forces and torques, sample shape (by
bending) and power requirements. The material properties are also
noticeably modified. An important shear deformation, characteristic
for this process, leads to texture rotation, microstructure refinement
and increase of material strength. Asymmetric rolling can be realized
by a modification of existing rolling mills; therefore, its industrial
application is possible at a relatively low cost.
The aim of the present study was to characterize this process and
resulting material modifications in the case of the polycrystalline
technically pure copper. The cases of low and high deformations
were examined. The EBSD, XRD, calorimetry and microhardness
measurements were performed. Texture and mechanical
characteristics were studied using a crystal deformation model and
FEM. The following material and process modifications were found
as a result of asymmetric rolling:
- sample bending, which can be partly controlled,
- decrease of mill load and an increase of the average rolling
torque,
- increase of microhardness,
- increase of energy released during recrystallization,
- distinct texture rotation around transverse direction,
- decrease of the average grains size (persisting in some
extent also after recrystallization) and formation of more
fragmented grains,
- modification of misorientation distributions.
ABSTRACTS THURSDAY PM2 - BOUNDARIES 106
Symposium B: Misorientation Textures at Grain Boundaries and Interfaces Symposium Chairs:
Dr. Eric Homer, Department of Mechanical Engineering, Brigham Young University
Dr. Srikanth Patala, Department of Materials Science and Engineering, North Carolina State University
Excess Dislocation Density near Boundaries as a Function of GB Texture D.P. Field Washington State University, Pullman, WA, USA.
Dislocation interactions with GBs have been discussed in the
literature on various levels with most focus being on the interaction
of individual dislocations with grain boundaries. Boundaries can be
barriers, sources, or sinks for dislocations. Excess dislocations
develop at many grain boundaries in a polycrystalline metal, but at
the same time, many grain boundaries are free of such dislocation
content. This study investigates excess dislocation content near
grain boundaries as a function of boundary character in lightly
deformed copper and IF steel.
Characterizing GB Dislocation Interactions though HR-EBSD and Machine Learning L.T. Hansen1, H.J. Bong2, J.D. Carroll3, D.T. Fullwood1, E.R. Homer1, and R.H. Wagoner2 1Brigham Young University, Provo, UT, USA. 2Ohio State University, Columbus, OH, USA. 3Sandia Nation Laboratories, Albuquerque, NM, USA.
The purpose of this research is to better understand the how
dislocations interact with GBs and specifically what GB
characteristics have the greatest effect on dislocation pileup. GBs in
strained polycrystalline tensile samples were characterized using
EBSD and optical microscopy. Geometrically necessary dislocation
(GND) build up at GBs was identified and quantified using high
resolution EBSD (HR-EBSD) in conjunction with a custom built
MATLAB routine. All GB information and GND build up information
was analyzed using machine learning; several preexisting theories
were validated and various trends identified. By using machine
learning on a large number of GBs, insights can be made which
would not otherwise be possible through human observation.
Study of Grain Boundary Character distribution in Annealed and Deformed Aluminum by 3D EBSD H. Pirgazi1 and L. A. I. Kestens1,2 1Ghent University, Ghent, Belgium. 2Delft University of Technology, Delft, The Netherlands.
Grain fragmentation and rotation of crystallographic orientations
have been the subject of many studies for decades. However, there
are still many ambiguities about the role of microstructural
parameters, especially grain boundaries, on these phenomena. The
reason of these ambiguities is mainly due to the lack of substantial
quantitative and comprehensive information. In this study, wide-
field conventional and 3D EBSD are employed to study the deformed
grains in an aluminum polycrystal, subjected to successive plane
strain compression test up to 30% deformation. Serial sectioning,
which includes consecutive steps of material removal and EBSD
measurement were employed to extract a stack of two-dimensional
sections of annealed and deformed samples and to reconstruct the
3D volumes.
Grain Boundary Character Distribution (GBCD) was derived from the
reconstructed 3D volume. The effect of the grain boundary affected
zone (GBAZ) was studied considering the local changes in
microstructure and crystallography in the vicinity of grain
boundaries. It was shown that at the early stages of deformation,
the crystals rotate and the grains are subdivided by the formation of
a rotation front, which was initiate at some specific grain
boundaries. After further deformation, the rotation front sweeps
through the grain and its misorientation increases simultaneously.
The experimental results of the crystal lattice rotation during
deformation were compared with the predictions of different crystal
plasticity models to the purpose of model validation.
Characterization of Grain Boundary Cracking Susceptibility in Pipeline Steels using Electron Backscatter Diffraction M.K. O’Brien, K.O. Findley
Colorado School of Mines, Golden, CO, U.S.A.
In the oil and gas industry, there is a desire to develop higher
strength low carbon steel pipelines that can be used at higher
operating pressures in sour service environments. The elevated
levels of hydrogen sulfide present in sour service environments are
thought to promote hydrogen ingress and cause internal cracking.
This process is known as hydrogen induced cracking (HIC).
Resistance to HIC is generally thought to decrease with increasing
strength levels. Therefore, it is desirable to understand the factors
that control susceptibility to HIC.
In this investigation, X52 and X70 steels were charged with hydrogen
to generate HIC, sectioned, and subsequently characterized using
electron backscatter diffraction (EBSD). Both X52 and X70 are low
carbon steels, with the former having a mixed ferrite/pearlite
microstructure, and the latter having a non-equiaxed, highly
substructured ferritic microstructure. Both steels have undergone
different thermomechanical processing paths that have resulted in
different grain boundary textures. To compare the as-received grain
boundaries to the damaged grain boundaries, misorientation angle
profiles and misorientation distribution functions with
accompanying discrete damaged plots were prepared. Most of the
coincident site lattice boundaries that occur with the highest
multiple of a random distribution (MRD) in the as-received samples
do not appear resistant to cracking, such as Σ27a in the X70 and
Σ13b in the X52 alloy. Σ3 boundaries in both the X52 and X70 alloys
were not resistant to cracking, unlike findings in many FCC systems.
In X70 however, Σ29a boundaries, which occur at the highest
multiple of a random distribution (MRD) in the as-received
microstructure, appear to be resistant to cracking.
ABSTRACTS FRIDAY AM - PLENARIES 107
FRIDAY AM PLENARY SESSION
Grain-Orientation-Dependent Fatigue Damage in Polycrystalline Materials Y.D. Wang1, W. Liu2, R.G. Li1 and S.L. Li2 1State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing, China. 2Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, USA.
The development of multiscale stresses under complex cyclic deformation modes is closely related to not only the evolution of texture but also the
localized damage in polycrystalline materials. For polycrystalline metals with the anisotropy in elasticity and plasticity, the stress gradient may vary
from several millimeters in engineering components serviced in complex stress fields, to micrometers caused by the existence of grain-to-grain or
phase-to-phase interaction, and even to submicrometer inside each grain due to strain/stress incompatibility over the whole plastic deformation.
The difference in deformation modes such as dislocation slip, mechanical twinning and phase transformation also enhances the complexity for
evaluating the multiscale stress distribution and local grain rotation. The advanced characterization methods, such as neutron diffraction,
synchrotron-based high-energy X-ray diffraction and X-ray micro-diffraction, indeed provide effective tools for studying the micromechanical
behavior, by which the multi-scale distribution in stress, grain rotation and localized damage can be well bridged in combination with the multiscale
crystal plasticity simulations. This presentation will give our recent work on the studies of micromechanical behaviors in fcc and hcp metals by the
state-of-the-art X-ray micro-diffraction and high-energy X-ray diffraction techniques with a focus on evolution of grain-orientation-dependent
stress and localized damage during cyclic deformation. Our experiments reveal directly the local grain orientation gradient and the evolution of
sub-micron scale stress distribution caused by specified dislocation configurations near localized shear bands. The experimental data provide local
stress distributions for verifying dislocation-based physical mechanisms on fatigue damage and to develop a local damage criterion for robust
fatigue life estimation.
Making and Breaking of Minerals, Rocks and Planets: A Textural Perspective S. Piazolo School of Earth and Environment, University of Leeds, UK.
In the geosciences, textures along with spatially controlled crystallographic orientation analysis is mainly used for deformation studies in the
crystal-plastic field. In these studies, the main interest lies either in deciphering the underlying processes of strain localization or in the geophysical
expression of textures indicative of deformation conditions in the deep Earth. However, in other research areas, orientation relationships can be
just as important. In the field of biomineralization, textural analysis shows that there is a distinct interplay between crystal growth regulated by the
organism itself and subsequent growth governed by the physics of crystal growth alone. The product is of exceptional strength and toughness.
Geological materials are commonly polymineralic and through in-flux of reactive hydrous fluid, melt or gas reactions occur at variable temperature
and pressure conditions. In many cases, the sequence of reactions and their progression is pivotal to our understanding in Earths’ or planetary
evolution.
The possibility to combine textural analysis with chemical analysis at a similar scale allows for new exciting avenues of research. For example, the
replacement reaction of a mineral (e.g. KBr) by another similarly structured mineral (e.g. KCl) results in textural relationships that can be easily
misinterpreted as microstructures originating from crystal plastic deformation unless the orientation relationships are studied in detail (1).
Similarly, if a feldspar, the most common mineral in the lower crust of the Earth, reacts with a reactive fluid, it will form complicated reaction and
inclusion textures, which if analyzed in detail can be used to determine the relative sequence of events (2).
The advent of Transmission Kikuchi Diffraction enabling orientation and chemical analysis at the nanometer scale (3) opens up new research fields,
promising to transform our understanding of geological processes at a fundamental level. For example, details of inter- and intragrain
crystallographic orientation relationships can help to determine if the enigmatic diamond aggregate “carbonado” has an extraterrestrial or
terrestrial origin (4). Furthermore, in-depth analysis of nanoscale reaction rims open up new avenues to understanding deep mantle processes.
Magnetite growth at the interface between pyrrhotite and diamond, allows for the first time to pinpoint the details of the carbon cycle deep within
the mantle (5). In fault zones nanoscale deformation structures are common; deciphering their origin and rheological consequence is essential for
hazard management. Preliminary data on experimental carbonate rich fault rocks show that during subseismic slip twin formation and dislocation
accumulation at grain boundaries along with brittle failure result in the production of a weak texture and nanoscale particles. Further deformation
causes mechanical dissociation producing amorphous carbon. However, different to common believe, little rheological weakening occurs with
these processes.
[1] Spruzeniece et al. (2017) Nat. Comms. 8. [2] Spruzeniece et al. (in press) Journal of Metamorphic Petrology [3] Trimby (2012) Ultramicroscopy 120, 16 [4] Piazolo et al. (2016) Lithos 265, 244
ABSTRACTS FRIDAY AM - PLENARIES 108
[5] Jacob et al. (2016) Nat. Comms. 7.
ABSTRACTS FRIDAY AM - DEFORMATION 109
Symposium D: Deformation Textures Session: Advanced Materials
Symposium Chairs:
Professor Chadwick Sinclair, Department of Materials Engineering, University of British Columbia
Professor Warren Poole, Department of Materials Engineering, University of British Columbia
Dr. Samantha Daly, Department of Mechanical Engineering, University of California, Santa Barbara
Development of crystallographic texture under shear strain in ultrahigh-strength strip steels A. Kaijalainen1, D. Lindell2, B. Hutchinson2 and D.A. Porter1 1Materials and Production Engineering, University of Oulu, Finland. 2KIMAB, Stockholm, Sweden.
The effect of subsurface microstructure on the crystallographic
texture of three 8 mm thick low-alloyed hot-rolled and direct-
quenched ultrahigh-strength strip steels with yield strengths in the
range 800 – 1100 MPa has been investigated. Detailed
microstructural features were further revealed by LCSM, FESEM and
FESEM-EBSD. Rolling to lower finish rolling temperatures increased
austenite pancaking leading to the formation of ferritic/granular
bainitic and the upper bainitic microstructures at the subsurface. In
addition, increased austenite pancaking was found to increase the
intensities of ~{112}<111>α and ~{110}<112>α - {110}<111>α texture
components in the surface layers, especially in upper bainitic
microstructures.
It is well known, that while austenite is deformed by rolling below
non-recrystallization temperature, there are shear texture
components in the austenite close to the rolled surfaces, i.e.,
{111}<211>γ and {112}<110>γ. After cooling and transformation to
ferrite these lead to the formation of shear components
{112}<111>α, {110}<112>α and {110}<111>α. However, specific
reason for the higher intensity of ~{112}<111>α texture component
in upper bainitic microstructure has not been sufficiently
investigated. Therefore, the influence of variant selection during the
transformation of austenite to the various ferritic microstructures
will be discussed.
Effect of Processing Methods on Texture Evolution and Recrystallization Studies on 14YWT Nanostructured Ferritic Alloys E. Aydogan1, S.C. Vogel1, S.A. Maloy1, C.A. Yablinsky1, O. Anderoglu2, G.R. Odette3 1Los Alamos National Laboratory, Los Alamos, NM, USA. 2University of New Mexico, NM, Albuquerque, USA. 3University of California Santa Barbara, Santa Barbara, CA, USA.
Nanostructured ferritic alloys (NFAs) are attractive materials for core
components in Generation IV reactors because of their excellent
high temperature strength, stability, and radiation damage
resistance [1-6]. It is very crucial to understand the microstructural
changes occurring during their processing and service. In this
research, two sets of experiments were conducted. First, the
stability of the 14YWT microstructure at different deformation levels
was investigated at temperatures above 1000 °C by an in-situ
neutron diffraction and electron backscatter diffraction techniques.
It has been found that the microstructure is very stable and
recrystallization starts at varying times depending on temperature
and deformation level. Second, texture of 14YWT cladding tubes,
produced either by spray forming followed by hydrostatic extrusion
or hot extrusion and cross-rolling followed by hydrostatic extrusion
has been studied using the above stated diffraction techniques at
room temperature. It has been found that hydrostatic extrusion
which is a combination of plane strain and shear deformations and
hot extrusion and cross-rolling which are plane strain deformations
result in distinct texture results. Moreover, although the total strains
are similar, shear dominated deformation leads to much lower
texture indexes compared to plane strain deformations.
[1] R.L. Klueh, D.J. Alexander, J. Nucl. Mater. 233–237 (1996) 336–
341. [2] G.R. Odette, M.J. Alinger, B.D. Wirth, Ann. Rev. Mater. Res. 38
(2008) 471–503. [3] S. Ukai, S. Ohtsuka, Energy Mater. 2 (2007) 26–35. [4] G.R. Odette, D.T. Hoelzer, JOM 62 (9) (2010) 84–92. [5] S. Ukai, in: Comprehensive Nuclear Materials, Elsevier B.V.,
Germany, Volume 4, Ch. 4.08, 2012. [6] G.R. Odette, JOM, 66(12) (2014) 2427-2441.
Spatially resolved texture and microstructure evolution of gas gun deformed SUS304 steel using neutron diffraction S. Takajo1, 2, C. P. Trujillo1, D. T. Martinez1, B. Clausen1, D. W. Brown1 and S. C. Vogel1 1Los Alamos National Laboratory, Los Alamos, USA. 2JFE Steel Corporation, Kurashiki, Japan.
Crystallographic phases in deformed SUS304 stainless steel, such as
martensitic phase by strain-induced martensitic transformation,
have long been investigated but there are few reports on its
quantitative analysis and texture. In this study, we report
characterization of a 38.1mm-long and 7.62mm-caliber SUS304
cylindrical projectile produced by additive manufacturing. The
projectile was accelerated at 235 m/s using the Taylor Anvil Gas Gun
Facility at LANL, impacting a high-strength steel anvil, leading to a
huge strain gradient inside the sample. Spatially resolved neutron
diffraction measurements on the HIPPO and SMARTS beamlines at
LANSCE with Rietveld and single peak analysis were used to
quantitatively evaluate volume fractions of , , and -phases as well
as residual strain and crystallographic texture, thus providing a
complete picture of the bulk micro-structural evolution. The neutron
diffraction measurements were complemented by EBSD analysis. It
was clarified that the -phase with {200} planes perpendicular to
the deformation axis was increased up to 5 volume percent by the
strain imposed during the deformation and no more than 1 volume
percent of -phase was formed, but only in the very slightly
deformed volume where little amount of -phase was detected.
These results suggested that the {200} texture evolution of (’)
phase during strain-induced martensitic transformation was hardly
ABSTRACTS FRIDAY AM - DEFORMATION 110
influenced by the existence of -phase. The data was compared to
an undeformed reference sample.
Texture Evolution Analysis in Oxide Dispersion Strengthened Ferritic Steel Transformed by a Tube Pilgering Process E. Vakhitova1,2, D. Sornin1 and M François2
1DEN-Service de Recherches Métallurgiques Appliquées, CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette, France. 2 Troyes University of Technology (ICD-LASMIS), 10010, Troyes, France.
Ferritic Oxide Dispersion Strengthened (ODS) steels are investigated
as potential materials for cladding tubes of advanced Sodium Fast
Reactors. Pilgering process is used to cold-form the ODS seamless
tubes with a large cross-section reduction in a double processing
step. To estimate the influence of process parameters on the
material, a microstructure analysis is carried out by Electron
Backscattering Diffraction (EBSD) and X-ray Diffraction (XRD)
methods. These data were used to obtain information about
crystallographic texture, misorientation distributions, grain size, low
and high angle boundary fractions and Schmid factor. Pilgered
samples show a high texture formation with the well-known α-fiber
preferential orientation along the rolling direction. During the heat
treatment process, grain morphology is restored from elongated
grains to the almost equiaxed ones, while the texture presents
unexpected increasing of fiber intensity. The remarkable
temperature stability of this fiber is assumed to be linked to the
texture memory of crystallographic structure during severe cold
rolling process. The special attention was paid to the slip activation
mechanism during plastic deformation applied by pilgering process.
To predict this specific texture formation, modeling investigation of
tube deformation process is performed using a polycrystalline self-
consistent visco-plastic (VPSC) code. Pilgering forming is modeled by
a sequence of deformation path considering the initial grain
orientation sets obtained from EBSD maps results. It assumes a
simple cyclic loading paths estimating the experimental loading
associated to the pilgering process. The effect of initial and induced
texture on the mechanical hardening is estimated and a set of
hardening parameters is identified. Finally, the results of the traction
tests along the rolling and transverse directions are compared to the
numerical simulations.
EBSD analysis of orientation gradients at grain boundaries N. De Vincentis1, A. Roatta1,2, M. Avalos1, R.E. Bolmaro1 and J.W. Signorelli1,2 1IFIR-UNR-CONICET, Rosario, Argentina. 2Facultad de Cs. Exactas, Ing. y Agrimensura (FCEIA-UNR), Rosario, Argentina.
The goal of this paper is to analyze the orientation gradients
developed in grain boundaries of a deep drawing quality steel
(AKDQ) with increasing deformation. The analysis was performed
using a notched specimen subjected to uniaxial tension interrupted
at different strain levels. The microstructure developed in different
zones through the notch at each strain condition was characterized
at sub-grain level spatial resolution using Electron Backscatter
Diffraction (EBSD). This configuration allowed to determine the local
evolution of the misorientation gradients developed in each grain
boundary of the selected zones. It was observed that the
misorientation decreased from the grain boundary to the core of the
grain, defining a region of influence of the grain boundary inside
each of its neighboring grains. In spite of the strictly-local
characteristic of the gradient, it was observed that the severity of
these grain boundary regions increased with mesoscopic plastic
strain, and that their width did not depend on grain size.
ABSTRACTS FRIDAY AM – RECRYSTALLIZATION 111
Symposium R: Crystallization, recrystallization and growth textures Symposium Chairs:
Dr. Rodney McCabe, Los Alamos National Laboratory
Asher Leff, Department of Materials Science and Engineering, Drexel University
Effect of Annealing Temperature on the Texture and Magnetic Barkhausen Noise of a Non-Oriented Electrical Steel (0.88 wt% Si) after Inclined Cold Rolling Youliang He1*, Mehdi Mehdi1, 2, Erik J. Hilinski3, Afsaneh Edrisy2 1CanmetMATERIALS, Natural Resources Canada, Hamilton, Ontario, Canada L8P 0A5. 2Department of Mechanical, Automotive, and Materials Engineering, University of Windsor, Windsor, ON, Canada N9B 3P4. 3Tempel Steel Co., Chicago, IL, USA 60640-1020
Non-oriented electrical steels are widely used in rotating machines,
electric vehicles or windmills as the lamination core for the electric
motors or generators. The crystallographic texture of the steel sheet
has a significant effect on the magnetic properties of the magnetic
core, thus affecting the performance and energy efficiency of the
motors or generators. To obtain the ideal <001>//ND (normal
direction) texture in the final steel sheets, inclined cold rolling was
employed in this research to process a 0.88 wt% Si non-oriented
electrical steel. After conventional hot rolling and annealing, the
steel was cold rolled at various angles (e.g. 0, 45, and 90) to the
hot rolling direction (HRD) with a thickness reduction rate of ~78%.
The cold-rolled sheets were then annealed at different temperatures
from 600 to 750C for 30 s to investigate the effect of annealing
temperature on the recrystallization and the formation of texture.
The microstructure and microtexture were characterized by optical
microscopy and electron backscatter diffraction (EBSD), and the
magnetic properties were evaluated by magnetic Barkhausen noise
(MBN) analysis. It was found that the cold-rolled steel partially
recrystallizes at 600C and 650C, and the progress of
recrystallization differs in samples incline-rolled at different angles
to the HRD, i.e. samples cold rolled at 45 to the HRD recrystallize
faster than the conventional (0 to HRD) or cross rolled (90 to the
HRD) samples. The initial cold rolling texture (mainly <110>//ND)
changes to the <001>//ND texture at lower annealing temperatures
(600 and 650C), while at higher temperatures (700 and 750 C), the
<111>//ND texture appears together with the strengthening of the
<001>//ND texture. The Magnetic Barkhausen noise of the samples
annealed at lower temperatures exhibits much higher values than
those annealed at higher temperatures. The anisotropy of MBN in
the conventionally rolled steel is apparently higher than those
incline-rolled or cross-rolled samples.
Study of the recrystallization kinetics in Fe3%Si steels during the 1st recrystallization using misorientation derived parameters (EBSD) in the CGO process F. Cruz-Gandarilla1, H.F. Mendoza-Leon2 R.E. Bolmaro3, A.M. Salcedo-Garrido1, J.G. Cabañas-Moreno4 and M. Avalos3 1Escuela Superior Física y Matemáticas. Instituto Politécnico Nacional, Ciudad de México, México. 2Centro de Nano micro y Nano Tecnología. Instituto Politécnico Nacional, Ciudad de México, México. 4Instituto de Física Rosario. CONICET. Universidad Nacional de Rosario. Rosario, Argentina. 4CINVESTAV IPN, Ciudad de México,
México
Fe3%Si alloys with Goss texture are essential in the manufacture of
electrical transformers. Obtaining these materials requires several
different sub-processing stages, like the one called primary
recrystallization, fundamental key process preceding abnormal grain
growth. The structure of grains and the different microstructural
aspects of this stage will determine the conditions for developing
the Goss orientation during abnormal grain growth [1].
The kinetics of recrystallization have been characterized by studying
properties, dependent on recrystallized volume, like hardness,
volume fractions of texture components, etc. The evolution of the
recrystallized volume has been modeled following the Johnson-
Mehl-Avrami-Kolmogorov (JMAK) formalism [2]. Recrystallized and
non-recrystallized grains are not uniquely characterized by these
global methods and a more local characterization is needed.
Recovery and recrystallization happening during heat treatments
involve changes in dislocation densities and their characteristic
arrangements, which are reflected in the measurements of
misorientations. Grain Orientation Spread (GOS), Grain Average
Misorientation (GAM), Kernel Average Misorientation (KAM), etc.
are useful parameters calculated from EBSD data to study these
variations [3].
The purpose of this work was to use those magnitudes (GOS, GAM
and KAM) calculated from several EBSD scans, performed at
increasing heat treatment times, to characterize the kinetics of the
1st recrystallization in an Fe3%Si alloy. Hardness measurements were
made simultaneously in order to validate the evolution of the
recrystallization by classical ways. It was found that the global GOS
(including grains of all orientations) shows a behavior similar to
hardness. When grains belonging to separate texture components
are analyzed, gamma grains are the first ones to recrystallize and
alfa grains the last. A further study is necessary to determine limits
for those parameters below which grains can be considered
recrystallized. The experiments suggest so far that there are not
unique values for all texture components.
[1] F. Cruz-Gandarilla, R. Penelle, T. Baudin, H.F. Mendoza León and J. G. Cabañas-Moreno. (2008) Proceedings of the 15th ICOTOM. Ceramic Transactions, Volume 200. 123, Ed. WILEY.
[2 F.J. Humpherys and M. Hatherly. RECRYSTALLIZATION AND RELATED ANNEALING PHENOMENA. (2004) 2dn Ed. ELSEVIER. ISBN: 0 08 044164 5
[3] F. Cruz-Gandarilla, A.M. Salcedo-Garrido, R.E. Bolmaro, T. Baudin, N.S. De Vincentis, M. Avalos, José G. Cabañas-Moreno, H.F. Mendoza-León. (2016) Materials Characterization 118, 332
Texture Evolution of a 3.2 wt% Si Non-Oriented Electrical Steel during Hot Band Annealing Mehdi Mehdi1, 2, Youliang He1, Erik J. Hilinski3, Afsaneh Edrisy2 1CanmetMATERIALS, Natural Resources Canada, Hamilton, ON, Canada L8P 0A5. 2Department of Mechanical, Automotive, and Materials Engineering, University of Windsor, Windsor, ON, Canada N9B 3P4. 3Tempel Steel Co., Chicago, IL, USA 60640-1020
ABSTRACTS FRIDAY AM – RECRYSTALLIZATION 112
To optimize the magnetic properties of non-oriented electrical
steels, it is required to carefully control all the stages of
thermomechanical processing during the production of the steel
sheets, since the microstructure and crystallographic texture at an
early stage will usually affect those at the subsequent stages. Many
studies have shown that hot band annealing may have a positive
effect on the texture of the final sheet, but it is not clear what are
the optimal annealing conditions to obtain the desired final textures.
In this study, the evolution of microtexture and microstructure of a
3.2% Si electrical steel during hot band annealing is studied by
tracking the nucleation and grain growth through electron
backscatter diffraction (EBSD) examinations. A region of the hot-
rolled sample was marked by micro-indents so that the same area
could be examined at various annealing times (under the same
temperature) to investigate the evolution of the microstructure and
microtexture during recrystallization. In this way, the mechanisms of
nucleation and grain growth can be elucidated, and optimal
annealing conditions can be determined.
Effect of solute Sn on the evolution of primary recrystallization texture in 3% Si-Fe R. Suehiro, Y. Hayakawa and T. Takamiya
Steel Research Laboratory, JFE Steel Corporation, Kurashiki, Japan
Solute atoms affect the formation of primary recrystallization
texture in 3%Si-Fe. In this study, effect of Sn addition in 3% Si-Fe
alloy on the evolution of primary recrystallization texture was
investigated. In the experiment, two steels, Sn-free (3.2mass% Si-
0.06mass% Mn) and Sn-bearing(3.2mass% Si-0.06 mass% Mn-0.1
mass% Sn) were cold rolled with 88% reduction rate and annealed
for primary recrystallization. The main texture component of
recrystallization texture just after completion of primary
recrystallization were almost similar {111}<112> in both steels. After
grain growth annealing at 850 °C, strong {111}<112> texture was
preserved in Sn-free steel, while strong {411}<148> texture
developed in Sn-bearing steel. In this study, the relationship
between solute Sn and the change of texture during grain growth
was focused on. The grain boundary misorientation angle
distribution f(ω) was calculated using EBSD. In Sn-free steel, f(ω) of
grain boundary with low misorientation angle ω(ω = 0-15°)
surrounding {111}<112> grains decreased significantly during grain
growth. On the other hand, almost no change of f(ω) in low ω region
was observed in Sn-bearing steel. For grain boundaries surrounding
{411}<148> grains, f(ω) with ω = 15-45° decreased and the
decrement of f(ω) was almost same for both steels. The decrease of
f(ω) during grain growth can be related to grain boundary motion. If
grain boundaries with specific ω move during grain growth,
frequency of these boundaries should decrease. Considering this
assumption, it can be considered that the movement of grain
boundaries surrounding {111}<112> grain was suppressed by the
existence of solute Sn. The grain boundary with low misorientation
angle (ω = 0-15) has lower mobility compared with high
misorientation angle (ω = 15-45) boundary. Since Sn is known as
grain boundary segregation element, following mechanism was
suggested. Sn segregates at grain boundaries surrounding
{111}<112> grains and suppresses the movement of low ω
boundaries during grain growth by Solute drag effect. In contrast,
Segregation of Sn to boundaries surrounding {411}<148> grains is
weakened since solute Sn atom cannot follow highly mobile
boundaries and weak Solute drag effect is exerted on these
boundaries. Therefore {411}<148> grains developed preferentially
during grain growth in Sn-bearing steel.
Influence of cold rolling reduction on secondary recrystallization textures in Fe-3%Si sheet T. Kataoka1, H. Atsumi1, N. Morishige1, M. Yasuda2 and K. Murakami2 1Hirohata R&D Lab., Nippon Steel & Sumitomo Metal Corporation, 1 Fuji-cho, Hirohata-ku, Himeji, Hyogo Prefecture, 671-1188 Japan. 2Yawata R&D Lab., Nippon Steel & Sumitomo Metal Corporation, 1-1 Tobihatacho, Tobata-Ku, Kitakyusyu City, Fukuoka Prefecture, 854-8501 Japan
In Fe-3%Si sheet, Goss ({110} <001>) orientation is the major
component of the secondary recrystallization texture. In order to
clarify the mechanism of the orientation selectivity in the secondary
recrystallization, many studies1-3) of the relationship between
primary recrystallization textures and secondary recrystallization
textures have been conducted. However, the mechanism of the
orientation selectivity in the secondary recrystallization has not
been perfectly clear yet.
The purpose of this work is to elucidate the influence of the primary
recrystallization textures on the secondary recrystallization textures
in Fe-3%Si sheet and to clarify the mechanism of the orientation
selectivity in the secondary recrystallization.
In this work, we demonstrate the primary recrystallization textures
and the secondary recrystallization textures of Fe-3%Si sheet. All the
sheets have the same thickness of 0.22mm, but the cold-rolling-
reduction rates are different, i.e., 90, 93 and 95%.
From our experimental results, the primary recrystallization textures
changed with the cold-rolling-reduction rates and consequently the
secondary recrystallization textures changed. Regarding the samples
cold-rolled at reduction rates of 90 and 93%, the major components
of the secondary recrystallization textures were {110} <001>. On the
other hand, the secondary recrystallization textures of the sample
cold-rolled at a reduction rate of 95% were mixtures of {110} <001>
and {110} <112> components. By comparing the frequency of Σ9
coincidence grains in the primary recrystallization textures with the
secondary recrystallization textures, we suggest that the grains
having the high frequency of Σ9 coincidence site lattice boundaries
play a key role in determining on the secondary recrystallization
textures.
[1] Y. Yoshitomo, Y. Ushigami, J. Harase, T. Nakayama and N. Takahashi (1994) Acta Metall, Mater 42, 2593.
[2] S. Arai, Y. Ushigami and N. Takahashi (1996) Mater. Sci. Forum 204, 617.
[3] T. Imamura, Y. Shingaki and Y. Hayakawa (2013). Metall and Mat Trans A 44, 1785.
ABSTRACTS FRIDAY AM - NUMERICS 113
Symposium N: Mathematical, Numerical and Statistical Methods of Texture Analysis Symposium Chair:
Dr. Oliver Johnson, Department of Mechanical Engineering, Brigham Young University
Spectral database constitutive representation within finite element and spectral micromechanical solvers for computationally efficient crystal plasticity modelling Marko Knezevica, Miroslav Zecevica, Daniel Savagea, Rodney J. McCabeb aDepartment of Mechanical Engineering, University of New Hampshire, Durham, NH 03824, USA bMaterials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
This paper presents the advances made in the development and
implementation of a novel approach to speeding up crystal plasticity
simulations of metal processing by one to three orders of magnitude
compared to the conventional approaches, depending on the
specific details of implementation. This is mainly accomplished
through the use of spectral crystal plasticity (SCP) databases
grounded in the compact representation of the functions central to
crystal plasticity computations. A key benefit of the databases is that
they allow for a non-iterative retrieval of constitutive solutions for
any arbitrary plastic stretching tensor (i.e., deformation mode)
imposed on a crystal of arbitrary orientation. Additionally, the
approach takes the advantages of a specialized computer hardware
integrating a graphics-processing unit and data compactions
methods based on the generalized spherical harmonics texture
representation. The paper emphasizes embedding SCP databases
within implicit finite elements and spectral micromechanical solvers.
To illustrate the potential of these novel implementations, results
from several process modeling applications including equi-channel
angular extrusion and rolling are presented and compared with
experimental measurements and predictions from other models.
A Model Based Iterative Reconstruction Algorithm for Pole Figure Inversion S. Singh, P. Kc and M. De Graef Carnegie Mellon University, Pittsburgh, USA.
The central problem in quantitative texture analysis involves the
determination of the Orientation Distribution Function (ODF), which
can be used to calculate orientation-averaged bulk anisotropic
quantities. Since this is such an important quantity of interest for
polycrystalline materials, there has been considerable effort in this
area. There are two primary methods for determining the ODF; one
approach uses the point-by-point orientation of grains using
electron diffraction techniques (EBSD, TKD) while the other
technique relies on using 2-D Pole Figures (PF) obtained by x-ray
diffraction (XRD). The first method allows for the direct computation
of the ODF, while the second method requires additional analysis to
reconstruct the ODF from the PFs; this reconstruction problem is
formally known as the Pole Figure Inversion problem. It has been
well known that the Pole Figure Inversion problem has many
parallels with the standard tomography problem. Because of
significant recent advances made in scalar tomographic
reconstruction techniques, it becomes meaningful to revisit the
inversion problem.
This contribution describes a new discrete method for inverting PFs
to estimate the ODF. Our approach makes use of a newly
constructed modified equal area Lambert projection for uniformly
sampling the 2-sphere S2 and combines this with the equal volume
“cubochoric” orientation representation used to obtain a uniform
sampling of orientation space, SO(3). Furthermore, a Model Based
Iterative Reconstruction (MBIR) algorithm with a q-Generalized
Gaussian Markov Random Field (q-GGMRF) prior model is used to
formulate the problem as a maximum a posteriori probability (MAP)
estimation problem. Thus, formulated objective function is
iteratively minimized to deduce the MAP estimate of the ODF. The
q-GGMRF parameters are fine-tuned to produce sharp or diffuse
textures. The efficacy of the new method will be evaluated with
both model and real experimental data and compared with existing
software including the MatLab based MTEX toolbox and the publicly
available software package popLA.
Mean-field modeling of recrystallization textures Miroslav Zecevica, Ricardo A. Lebensohnb, Rodney J. McCabeb, and Marko Knezevica aDepartment of Mechanical Engineering, University of New Hampshire, Durham, NH 03824 USA. bMaterials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87544.
This paper presents recent advances made in extending well-
established texture and deformation mechanisms based mean-field
deformation models such as visco-plastic self-consistent (VPSC) to
predict recrystallization texture evolution. Deformation textures for
cubic and orthorhombic crystal structure materials are predicted
using the VPSC model capable of calculating statistical distributions
of intragranular misorientation fields within grains. The
recrystallization model incorporates laws for nucleation and grain
growth for simulating recrystallization textures. Consistent with
experimental evidence, the nucleation is assumed to occur at
transition bands developing within the grains and at high angle grain
boundaries. Grain growth is driven by the strain energy difference
between the grain and surrounding effective medium. The predicted
recrystallization textures are compared with experiments and
reasonable agreement is obtained in a computationally efficient
manner (computational time is on the order of minutes).
Estimation of the orientation distribution function using incomplete sets of pole figures data H.G. Brokmeier1 1Inst. of Materials Science and Engineering TU Clausthal, Clausthal-Zellerfeld, Germany.
One way to estimate the orientation distribution function (ODF) is
based on mathematical calculations using experimental pole figure
data obtained by X-rays, neutrons and synchrotron-radiations. The
key task of such an experiment is sufficient scanning of the polar
ABSTRACTS FRIDAY AM - NUMERICS 114
sphere for high quality input data for ODF-calculation. On one hand
experiments are in practice time consuming and standard scanning
routines are worldwide in use which may not fit the requirements to
obtain correct textures. Any scanning routine should reflect the pole
figure window, the beam divergence and texture sharpness. One
example is in case of sharp textures in which a pole figure scanning
routine of Δα=5° and Δβ=5° is used. According to standard
instrumental resolution functions, the coverage of the polar sphere
is incomplete and don’t reflect the true texture. On the other hand,
experimental conditions like laboratory X-ray diffraction, or
synchrotron diffraction of large pieces, or in-situ texture evolution
studies lead to different kinds of incomplete sets of pole figure data.
Today ODF-software is easily available, which looks like that all
problems can be solved. Examples will be presented that even
excellent ODF software still needs high quality input data for a
sufficient estimation of the “true ODF”. Texture analysis of Mg and
its alloys is a key task in light-weight materials, but due to the special
texture of Mg it is not easy to get good Mg-textures with all texture
components and texture sharpness by laboratory X-rays. Many
present papers showing recalculated pole figures from the ODF
showing still separate areas for measured part and recalculated part,
which opens the question: how good is the ODF-calculation? A
special situation is also given for in-situ experiments. Mostly, we
have blind areas which can be filled in some cases quite well and in
other cases with some errors by the ODF. One can find this for all
kinds of materials even in high symmetric cubic metals. ODF-
calculation and pole figure measurement have to go hand in hand.
Application of the symmetrized Bingham distribution and other parametric distributions for the modelling of texture uncertainty Stephen Niezgoda, James Matuk, Oksana Chkrebtii and Carl Ahlborg The Ohio State University, Columbus OH, USA.
The estimation of orientation distribution functions (ODFs) from
discrete orientation data, as produced by electron backscatter
diffraction or crystal plasticity micromechanical simulations, is
typically achieved via techniques such as the Williams–Imhof–
Matthies–Vinel (WIMV) algorithm or generalized spherical harmonic
expansions, which were originally developed for computing an ODF
from pole figures measured by X-ray or neutron diffraction. These
techniques often rely on ad-hoc methods for choosing parameters,
such as smoothing half-width and bandwidth, and for enforcing
positivity constraints and appropriate normalization. In general, such
approaches provide little or no guarantees as to their optimality in
describing the given dataset. In the current study, a finite mixture of
Bingham distributions, symmetrized to reflect arbitrary
crystallographic and sample symmetry, is used to estimate ODFs
from discrete orientation data. Two algorithms will be discussed i)
an unsupervised learning approach which introduces a minimum
message length criterion, a common tool in information theory for
balancing data likelihood with model complexity, to determine the
number of components in the Bingham mixture and ii) an optimal
Bayesian inference approach which uses a birth-death Markov chain
Monte-Carlo sampling scheme. The latter approach is of particular
interest as it provides a methodology for performing uncertainty
quantification of texture, can provide error bounds on the
orientation distribution function measured from a given sample, and
gives a statistically rigorous framework for comparison of texture
between samples or characterizing the variance in texture across an
ensemble of samples.
ABSTRACTS FRIDAY AM - ENGINEERING 115
Symposium A: Texture and Anisotropy in Advanced Engineering Processes and Materials Session: Advanced Processing - Forging and Extrusion
Symposium Chairs:
Professor Tracy Nelson, Department of Mechanical Engineering, Brigham Young University
Dr. Ashley Spear, Department of Mechanical Engineering, University of Utah
Microstructure and texture evolution during modified multi-axial forging of Magnesium alloy Mg–3Al–0.4Mn Somjeet Biswas Department of Metallurgical and Materials Engineering, Indian Institute of Technology kharagpur, Kharagpur, India.
Wrought Magnesium (Mg) alloys have high potential for
automobile/aerospace structural applications. However, Mg alloy
usage is restricted due to its low strength, low ambient temperature
ductility and high anisotropy owing to its hexagonal closed packed
(hcp) structure. Usage of Mg alloys will lead to the reduction of
carbon emission in atmosphere and thus the environmental impact
of motored vehicles. In this work, an attempt was made to produce
ultra-fine grain (UFG) size and weak texture in a single-phase Mg
alloy Mg–3Al–0.4Mn by modified multi-axial forging (MAF) process.
An average grain size of ~0.4 µm and weak texture could be
achieved. This led to the improvement in strength, room
temperature ductility and reduction in anisotropy. The
microstructural characterization was performed using the electron
back scattered diffraction (EBSD) technique in a field emission gun –
scanning electron microscope (FEG-SEM). Visco-plastic self-
consistent (VPSC) modeling was used to predict the deformation
texture and the underlining deformation mechanism. The grain
refinement mechanism and the associated dynamic recrystallization
and its effect on the deformation texture were studied.
[1] S. Biswas, S. Suwas (2011) Scripta Materialia. 66, 89.
Characterization of microstructure and texture in 6013 aluminum alloy after large strain extrusion machining process Xiaolong Bai1,3, Zhimin Qi1, Srinivasan Chandrasekar2,3, Kevin Trumble1,3
1School of Materials Engineering, Purdue University, West Lafayette, IN, USA. 2School of Industrial Engineering, Purdue University, West Lafayette, IN, USA. 3Center for Materials Processing and Tribology, Purdue University, West Lafayette, IN, USA
Commercial production of 6xxx aluminum alloy sheets consists of
multi-stage hot and cold rolling processes that result in final Cube
(100) [001] and Goss (110) [001] textures, which are unfavorable to
subsequent forming operations. In this study, large strain extrusion
machining (LSEM), a technique to impose large shear strains at high
strain rate within a narrow deformation zone, was employed to
make thin strip directly from as-cast AA6013 alloy. The resultant
microstructure after LSEM processing contains three different zones:
the primary shear zone due to the shear in the narrow deformation
zone; the secondary shear zone originating from friction between
the cutting tool and sheet; and the constraint zone resulting from
friction between the constraint tool and sheet. The thickness of the
three zones, especially the primary shear and constraint zone, can
be controlled by deformation parameters (strain, strain rate and
temperature). Partial {111} and <110> fiber textures are developed
during the LSEM process of the AA6013, which is characteristic of
FCC metals exposed to simple shear deformation. Due to the friction
effect, however, the shear angles in the three zones are different
and can be controlled by the deformation parameters.
Microstructures of as-cast and as-deformed materials are
characterized by optical microscopy and crystallographic textures
are analyzed by x-ray diffraction. The results are compared with
those from the conventional rolling process and the advantages and
applications are discussed.
Microstructure and Texture Evolution of Magnesium alloy after Shear Assisted Processing and Extrusion (ShAPE) M. Jamalian1, V. Joshi2 and D.P. Field1
1School of Mechanical and Materials Engineering, Washington State University, Pullman, USA. 2Pacific Northwest National Laboratory, Richland, USA
Magnesium alloys have been an area of interest in various industries
such as transportation due to the high strength and low density.
However, a limitation of utilizing magnesium is the inability of
forming it. An effective way of achieving optimum mechanical
properties is modifying grain size and texture. Shear Assisted
Processing and Extrusion (ShAPE) is a novel process that is used for
fabricating thin-walled magnesium tubing. This study analyzes the
microstructure and texture of the alloy at various stages of the
process by using electron backscatter diffraction (EBSD). Notable
differences in grain size and texture were observed depending on
location examined within the extrusion. Wall thicknesses of 60 and
120 mils were characterized showing that the grain size and basal
plane orientation changed significantly as a function of position
within the extrudate, with especially severe changes near the edges.
This type of microstructural information can be used to tune the
parameters of ShAPE.
Texture development in Al-Mg-Si alloys extruded through porthole dies Jingqi Chen 1, Yahya Mahmoodkhani 2, Yu Wang2, Nick C. Parson3, Mei Li4, Mary A. Wells2, and Warren J. Poole1 1The University of British Columbia, Vancouver, British Columbia, Canada. 2University of Waterloo, Waterloo, Ontario, Canada. 3Rio Tinto Aluminium, Jonquière, Québec, Canada. 4Ford Motor Company, Dearborn, Michigan, USA
The extrusion of hollow profiles from aluminum alloys can be done
use a porthole die. In a porthole die, the aluminum is split into
multiple feeds which pass around a bridge in the die and then re-
weld together. In this work, an idealized porthole die was used
where a round billet was extruded into a strip with a bridge in the
centre of the strip. The material used in the trials was an aluminum
alloy based on AA6082 with a high dispersoid content to inhibit
ABSTRACTS FRIDAY AM - ENGINEERING 116
recrystallization. The texture and microstructure was characterized
by electron backscatter diffraction maps. In comparison with the
conventional strip extrusion where there is no bridge in the die, the
porthole die extrusion displays a strong texture variation around the
centre weld line. Moreover, the conventional strip extrusions had a
typical plane strain deformation texture seen for high temperature
deformation of aluminum, i.e. a mixture of copper, S, and brass
orientations. In contrast, the porthole die extrusion exhibits
individual texture components which vary from the near the weld
line. In detail, for the areas close to the centre weld line, only the
copper-type texture can be observed, whereas about 0.4 mm from
the weld line, as single component of the brass texture is observed.
To explain this phenomenon, a combination of fine-element method
and visco-plastic self-consistent texture simulations was employed
to predict the variation of texture components around the weld line.
Synergic effect of Mg addition and hydrostatic extrusion on microstructure and texture of biodegradable low-alloyed zinc A. Jarzębska1, M. Bieda1, J. Kawałko1, P. Koprowski1, Ł. Rogal1, K. Sztwiertnia1, B. Kania1, R. Chulist1, W. Pachla2, M. Kulczyk2 1Institute of Metallurgy and Materials Science, Polish Academy of Sciences, Krakow, Poland. 2Institute of High Pressure Physics, Polish Academy of Sciences, Warszawa, Poland
The purpose of researches was to investigate the influence of
different content of Mg combine with plastic deformation in the
room temperature on microstructure and texture of low-alloyed zinc
(ZnMg). In order to study those effects Zn alloys with various
amount of Mg were casted and subsequently subjected to
hydrostatic extrusion (HE) and compared to pure zinc. Detailed
analysis of microstructure and local texture of obtained materials
was received from scanning electron microscope observation and
electron back scatter diffraction experiment and was performed on
both longitudinal and transvers cross sections of each sample.
Information about the global texture has been investigated with the
use of X-ray diffraction technique.
Results showed that HE led to grain refinement on the level that was
unattainable for classical methods of deformation both in pure Zn
and in ZnMg alloys. Microstructure of pure Zn was characterized by
equiaxed grains on both cross sections. This observation together
with local and global texture analysis received from transverse cross
section suggest occurrence of dynamic recrystallization during
plastic deformation. Addition of Mg caused major changes in
microstructure and texture of deformed materials and provoked
even larger grain refinement. On longitudinal cross section of ZnMg
bimodal structure composed of elongated grains in extrusion
direction and equiaxed one's were noticed.
Hydrostatic extrusion and alloying caused great modification in
microstructure and texture of low-alloyed zinc which corresponded
to significant improvement in mechanical properties.
ABSTRACTS FRIDAY AM - ENGINEERING 117
Symposium A: Texture and Anisotropy in Advanced Engineering Processes and Materials Session: Advanced Engineering Processes
Symposium Chairs:
Professor Tracy Nelson, Department of Mechanical Engineering, Brigham Young University
Dr. Ashley Spear, Department of Mechanical Engineering, University of Utah
Material Forensics H. Garmestani1, E. Hoar1, A. Tabei1, Z. Pan1, S. Liang1, D. Shih2 1Georgia Institute of technology, Atlanta, GA, USA. 2Boeing, St. Louis, MI, USA
A review of the research on investigating the effect of high speed
machining on the near-surface microstructures of Al7075 and Ti64 is
presented here. It is shown that the high-speed machining process
can introduce a texture and grain size gradient in the machined
surface in these alloys. A physics-based finite element method is
proposed for the modeling of machining-induced phase
transformation and grain size growth. Prediction of the grain
growth and phase transformation are obtained with the Johnson-
Mehl-Avrami-Kolmogorov (JMAK) dynamic recrystallization model
and Avrami model, respectively [1]. A modified Johnson Cook flow
stress model is embedded into the method to account for the phase
transformation. The accuracy of the proposed method is validated
with experimental data. Parametric studies are conducted to
investigate the effects of the cutting speed and the feed rate on the
microstructure change in machining. The experimental micro-
texture and grain size distribution data are used to develop a
process path model that can be used to link to machining
parameters.
[1] Z. Pan, S. Y. Liang, H. Garmestani, D. S. Shih (2016), Int J Adv Manuf Technol, 87:859–866
EBSD Analysis of Pt-20Ir Wire as Lead Conductor in Implantable Medical Device Kailynn Cho and Bernard. Q. Li Medtronic Neuromodulation, 7000 Central Ave. NE, Minneapolis MN 55432, USA.
Pt-20Ir cold drawn wire has been used as lead conductor in
implantable medical devices. The lead is a device to transfer the
electrical signal to the area for stimulating such as brain and
neurological nerves. The Pt-20Ir wire demonstrated the good
biocompatibility and stability. Although Pt-20Ir wire has been used
in leads more than 20 years, there is lack of published data in
literature on its microstructure. Due to inert nature the Pt and its
alloys are difficult to be prepared as metallography for grain
structure analysis. By using EBSD technique, the Pt-20Ir sample
does not need to be etched and its high atomic number is able to
generate high quality backscatter pattern. In this study, the Pt-20Ir
wire was analyzed for its grain structure, grain boundary and
texture.
Recrystallization and crystal growth phenomena during Rolling Contact Fatigue and White Etching Crack formation of AISI 52100 bearings A. Schwedt1, V. Šmeļova1,2, A. M. Diederichs1,*, M. O. Özel3, T. Janitzky3, J. Mayer1, L. Wang2, C. Broeckmann3, W.Holweger2,4 1Central Facility for Electron Microscopy (GFE), RWTH Aachen University, Aachen, Germany. 2National Centre for Advanced Tribological Studies (nCATS), Faculty of Engineering and the Environment, Southampton University, Southampton, UK. 3Institute for Materials Applications in Mechanical Engineering (IWM), Faculty of Mechanical Engineering, RWTH Aachen University, Aachen, Germany. 4Schaeffler Technologies GmbH & Co. KG, Tribology Fundamentals, Herzogenaurach, Germany. *Present address: Department of Mechanical Engineering, Materials and Surface Engineering, Technical University of Denmark, Kgs. Lyngby, Denmark.
Besides classical Rolling Contact Fatigue (RCF) the unpredictably
occurring formation of White Etching Crack (WEC) networks has
been identified as a major cause of failures of AISI 52100 bearings in
a wide range of applications.
Recent studies have shown that in both cases (for RCF cf. [1], for
WEC cf. [2]) a large variety of microstructural alterations occur, e.g.
in terms redistribution of alloying elements, heterogenization of
local microhardness, and especially recrystallization and growth of
ferritic grains in various grains size ranges and shapes.
EBSD measurements show, that the microtexture of these
components is not random – in the case of high-stress RCF it can be
well connected to the outer rolling conditions ([1]), in the case of
WECs the prevailing textures are more complex and locally varying
within the crack network. An overview of examples from WECs
formed under different conditions and lifetimes will be presented.
The examples comprise failed bearings from real applications, as
well as test samples from various test rigs such as industrial L11 or
L24 test rigs at Schaeffler or a 4-disc test rig at RWTH Aachen
University.
It will be discussed, how far the textures found for the
microstructural alterations in failed and test-rig samples can give
insight into the formation mechanisms of the observed
microstructure alterations.
[1] V. Šmeļova, A. Schwedt, L. Wang, W. Holweger, J. Mayer (in press), Intl. J. of Fatigue, DOI:10.1016/j.ijfatigue.2017.01.035.
[2] A. M. Diederichs, A. Schwedt, J. Mayer, & T. Dreifert (2016), Materials Science and Technology 32, 1683-1693.
Individual effect of recrystallization nucleation sites on texture weakening in a magnesium alloy Dikai Guan, W. Mark Rainforth*, Brad Wynne Department of Materials Science and Engineering, University of Sheffield, Sheffield S1 3JD, UK
ABSTRACTS FRIDAY AM - ENGINEERING 118
Recrystallized grain nucleation, grain growth and corresponding
texture evolution in a cold-rolled rare earth containing WE43 Mg
alloy during annealing at 490 °C was fully tracked using a quasi-in-
situ electron backscatter diffraction method. The results show
nucleation sites, such as double twins, can weaken the deformed
texture and for the first time provide direct evidence that
recrystallized grains originating from double twins can form the rare
earth texture (RE texture) during annealing. The RE texture emerges
during the nucleation of recrystallized grains and is maintained
during subsequent grain growth, which results in a stable RE texture
being developed as recrystallization progresses. Precipitation and
recrystallization occurred concurrently during most of the annealing
period, with precipitates forming preferentially along prior grain and
twin boundaries. These precipitates effectively retard the
recrystallization due to particle pinning leading to an excessively
long time for completion of recrystallization.
Materials-Affected Manufacturing: Inverse Model for the Simulation of Texture Evolution in Ti64 through Turning Eric Hoar1, Zhipeng Pan2, Ali Tabei1, Jason Allen1, Peter Bocchini3, Hamid Garmestani1, Steven Liang2 1School of Materials Science and Engineering, Georgia Institute of Technology. 2G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology. 3Boeing Research & Technology
The goal of materials-affected manufacturing research is to
understand the material evolution during different manufacturing
processes. This project focuses on understanding and simulating the
texture evolution of titanium alloy, Ti64 through the process of
turning. By understanding the texture evolution of Ti64 it is possible
to invert the process. This allows for the determination of a
required initial microstructure in order to reach a specific desired
microstructure through turning. Here we present on our current
results in simulating the texture evolution in Ti64 due to turning.
ABSTRACTS POSTERS 119
POSTER SESSION
Tuesday Evening 7th November 2017
ABSTRACTS POSTERS A 120
Symposium A: Texture and Anisotropy in Advanced Engineering Processes and Materials Session: Advanced Materials
Symposium Chairs:
Professor Tracy Nelson, Department of Mechanical Engineering, Brigham Young University
Dr. Ashley Spear, Department of Mechanical Engineering, University of Utah
A-1 Evolution of microstructure and texture in AA1100 during multi-axial diagonal forging J.-H. Shin1, M.-S. Kim1, S. C. Kwon2, S.-T. Kim2, S.-H. Lee3, S.-H. Yang3, S. Lee3, S.-H. Choi1 and H.-T. Jeong2 1Department of Printed Electronics Engineering, Sunchon National University, Sunchon 57922, Republic of Korea. 2Department of Advanced Metal and Materials Engineering, Gangneung-Wonju National University, Gangneung 25457, Republic of Korea. 3Agency for Defense Development, Yuseong-si, Daejeon 34186, Republic of Korea.
Evolution of microstructure and texture in a commercially pure
aluminum (AA1100) during multi-axial diagonal forging (MADF)
process was investigated by microstructural analysis and polycrystal
modelling. MADF process was developed as a novel severe plastic
deformation (SPD) technique to impose a uniform strain throughout
the whole specimen. Characterization of microstructure in AA1100
was conducted using optical microscope (OM) at each MADF step.
Micro-hardness distribution was used to investigate the strain
homogeneity on cross-sectional plane of forged specimens during
consecutive MADF steps. In order to analyze the evolution of
microstructure and texture on cross-sectional plane of forged
specimens during MADF process, electron backscatter diffraction
(EBSD) technique was applied. Three dimensional finite element
analysis (FEA) using the commercial software (DEFORMTM-3D) was
conducted to simulate the deformation behavior during MADF
process. The deformation history calculated by FEA was used for
visco-plastic self-consistent (VPSC) polycrystal model to predict
microtexture evolution during MADF process. Microstructure of
AA1100 deformed by MADF process exhibited relatively weak
texture and homogeneous microstructure with fine grains compared
to the other SPD processes.
A-2 Development of micro fibril textures in melt-spun polyamide-6 fibers by transversal compression N. Wirch1, R. Ghadimi2, T. Vad3 and T.E. Weirich1,4 1Central Facility for Electron Microscopy (GFE), RWTH Aachen University, Aachen, Germany. 2Tietz Video and Image Processing Systems GmbH, Gauting, Germany. 3Institute for Textile Engineering (ITA), RWTH Aachen University, Aachen, Germany. 4Institute of Crystallography (IFK), RWTH Aachen University, Aachen, Germany.
The investigation of ultrathin cross-sections of melt-spun polyamide-
6 (PA6) fibers by low-dose electron diffraction revealed a hitherto
unknown texture within the plane normal to the main fiber axis. This
texture could only be found in cross section samples with
pronounced ripples and disruptions due to the transversal forces
imposed on the fibers during ultra-thin sectioning. The developed
texture is thus the result of the reorientation of the crystalline nano-
fibrils inside the yarn under transversal compression stress. Using
the results from electron diffraction and complementary
measurements by wide-angle x-ray diffraction (WAXD) on the same
material enabled us to develop a structural model of the interior of
the fibers on the nanoscale. The within this study obtained results
are likely of great interest for calculations of materials properties of
individual fibers and the therefrom obtained products as well.
A-3 Microstructure and Texture of Titanium grade 2 after ECAP Processing M. Wroński1, K. Wierzbanowski*1, R. Z. Valiev2,3, J. Kawałko4, K. Sztwiertnia4 and E. Szyfner1
1AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, 30-059 Kraków, Poland. 2Institute of Physics of Advanced Materials, Ufa State Aviation Technical University, 450000 Ufa, Russian Federation. 3Laboratory for Mechanics of Bulk Nanomaterials, Saint Petersburg State University, Peterhof, Saint Petersburg, 198504, Russia. 4Institute of Metallurgy and Materials Science, Polish Academy of Sciences, 30-059 Kraków, Poland
In the last years one observes a strong development of different
methods devoted to produce ultrafine materials. Equal Channel
Angular Pressing (ECAP) is one of the oldest one and it is still being
developed and examined. In the present work the properties of
titanium grade 2, deformed at 3000 C by ECAP process, are studied.
Polycrystalline titanium has many technological applications in
aerospace and transport industries as well as in bio-engineering,
therefore it is a subject of intense research. Texture development
and selected microstructure parameters of titanium after
deformation (four and eight ECAP passes - route C) and after
recrystallization were studied using electron backscatter diffraction
(EBSD) technique. Also, mechanical properties, like microhardness
and strain-stress relations, were examined. After ECAP deformation
the material properties were strongly modified. The grain size
decreased radically (and more fragmented grains were formed), the
defect density increased, the proportion of low and high angle
boundaries changed and material hardness as well as mechanical
strength increased noticeably. Also, a characteristic texture was
formed. Generally, it was noted that major modifications of material
characteristics appeared after initial four ECAP passes. The
consecutive four ECAP passes led already to much smaller
modifications of material properties.
A-4 Texture, microstructure and mechanical properties evolution in Fe-(x=36 and 48 wt.%) Ni alloy after accumulative roll bonding S. Boudekhani-Abbas1, K. Tirsatine1, H. Azzeddine1,2, B. Alili1, A.L. Helbert3, F. Brisset3, T. Baudin3, D. Bradai1 1Faculty of Physics, University of Sciences and Technology Houari Boumediene, BP 32 El-Alia, 16111, Algiers, Algeria. 2 Departments of Physics, University of M’sila, Algeria. 3 ICMMO, SP2M, Univ. Paris-Sud, Université Paris-Saclay, UMR CNRS 8182, 91405 Orsay Cedex, France
ABSTRACTS POSTERS A 121
Up to now, among severe plastic deformation (SPD) techniques, only
accumulative roll bonding (ARB) processing has a great potential to
be adapted to the industry in order to produce Ultra-Fine Grain (UFG)
materials in the geometry of large sheets due to its possibility as
continuous process. Severe plastic deformation processing can lead
to significant changes in crystallographic texture compared to the
conventional ones such as compression or rolling. Texture developed
after ARB processing is generally characterized by rolling-type
components at the mid-thickness and shear-type components near
the surface. However, there is a strong lack of studies on the effect of
some special parameters such as deformation temperature, sample
preparation or solute content on texture.
The aim of the present work is to investigate the effect of solute
content on the texture, microstructure and mechanical properties
evolution after severe plastic deformation of a Fe-x(x=36 and 48
wt.%) Ni alloy by ARB processing.
The EBSD maps show a substantial grain refinement, more or less the
same for both alloys. Grains are of elongated shape and the grain
aspect ratio (defined as the ratio of the maximum grain distance to
the minimum one) reached a value near 2.5. Both samples exhibit a
different texture evolution upon straining. The Fe-48Ni (wt.%) alloy,
with a quasi-random initial texture, developed a Rotated-cube
component after 1 to 3 cycles and subsequently a Copper component
dominated after 6 cycles. However, the Fe-36Ni (wt.%) alloy, with a
strong Cube initial texture, developed a Brass component (after 3
cycles) then a Rotated-Cube component (5 cycles) and finally a
Copper-type texture after 6 cycles. The microhardness of both alloys
shows the same trends up to 6 cycles. That of Fe-48Ni (wt.%) alloy is
somewhat higher than that of Fe-36Ni (wt.%) alloy by 10% beyond the
first cycle. The effect of solute content is mainly discussed in term of
stacking fault energy.
A-5 Characterization of Fe-Co soft ferromagnetic alloys processed by laser engineered net shaping (LENS) Andrew B. Kustas, Kyle L. Johnson, Shaun R. Whetten, Dave M. Keicher, Mark A. Rodriguez, Daryl J. Dagel, Joseph R. Michael, Nicolas Argibay, Don F. Susan Materials Science and Engineering Center, Sandia National Laboratories, Albuquerque, NM, 87123
Fe-Co alloys possess favorable magnetic properties for
electromagnetic applications. However, poor workability caused by
atomic ordering can lead to cracking during conventional processing.
In this study, we explore an innovative solidification-based
processing approach to produce bulk forms of Fe-Co alloys using
Laser Engineered Net Shaping (LENS). As model materials,
equiatomic Fe-Co and Fe-Co-1.5V alloys are explored.
Microstructure of LENS specimens are characterized in terms of
grain size, crystallographic texture, and degree of atomic ordering.
Preliminary mechanical and magnetic properties are also discussed.
Sandia National Laboratories is a multi-mission laboratory managed
and operated by National Technology and Engineering Solutions of
Sandia, LLC., a wholly owned subsidiary of Honeywell International,
Inc., for the U.S. Department of Energy’s National Nuclear Security
Administration under contract DE-NA-0003525
A-6 directionally solidified non-modulated Ni54Mn24Ga22 alloys in a gradient magnetic field Long Houa, Yanchao Daia, Zongbin Lib, Yikun Zhanga, Zhongming Rena, Xi Lia,* aState Key Laboratory of Advanced Special Steels, Shanghai University, Shanghai 200072, China bKey Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang 110819, China
The microstructural feature of the non-modulated martensite in
Ni54Mn24Ga22 alloys directionally solidified under the magnetic field
has been investigated based on electronic backscatter diffraction
(EBSD) measurements. The results show that the application of
magnetic field promoted the formation of [001]M orientation along
the growth direction, in contrast to dominant [110]M orientation
without magnetic field. By considering the Schmid factors, the
influence of the magnetic force due to the magnetic field gradient
on the variant selection was further analyzed. It is suggested that
magnetic force derived from magnetic gradient could be employed
for the microstructure control in Ni-Mn-Ga alloys.
ABSTRACTS POSTERS B 122
Symposium B: Misorientation Textures at Grain Boundaries and Interfaces Symposium Chairs:
Dr. Eric Homer, Department of Mechanical Engineering, Brigham Young University
Dr. Srikanth Patala, Department of Materials Science and Engineering, North Carolina State University
B-1 Obtaining 5D Grain Boundary Character from Surface EBSD using Band Intensity Profiles A. Amalaraj, J. Christensen, O.K. Johnson, E.R. Homer, D.T. Fullwood Brigham Young University, Provo, USA.
Grain boundary (GB) character strongly affects behavior of
materials. Hence, characterizing the full GB character is critical for
informing and validating material models. Surface EBSD typically
reveals only 4 of the 5 GB characteristics (relative orientation of the
grains and trace). To obtain the GB inclination, serial sectioning
(often destructive in nature) is usually performed. Here, a new non-
destructive approach is taken at determining the inclination of a GB.
If a line scan is taken across a GB, the rate of transition from the
EBSD pattern of one grain to the pattern of the second, relates to
the shape of the interaction volume, and the geometry of the GB;
more specifically, the inclination angle of the grain boundary with
respect to the scan’s path. The intensity of a given band in an EBSD
pattern is readily measured from the Hough transform of the
pattern, and provides an indication of the number of electrons
impacting the phosphor, that were emitted from a given grain. The
height of the Hough peak, for bands not shared by both grains, will
taper off as the GB is approached and crossed. The summed and
normalized intensity of the dominant bands within a grain is tracked
to provide a curve that reflects electron contribution to the EBSD
pattern from a given grain. This curve is compared with a library of
theoretical curves, arrived at via Monte Carlo modeling of electron
interactions in the area of all possible geometrical GB configurations.
The best-fit curve indicates the GB inclination. The method is
validated using GBs of annealing twins in nickel.
B-2 Effect of grain boundary engineering on the corrosion behavior of Hastelloy C-276 J. Vijay Bharadwaj1, B. Shakthipriya1 and V. Subramanya Sarma1 1Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai, INDIA.
Ni base superalloys which have excellent aqueous and hot corrosion
resistance are widely used in petrochemical and other chemical
industries are subject to highly corrosive environments at elevated
temperatures in service. The damage during service is mostly due to
degradation mechanisms like intergranular corrosion, sensitization
and hot corrosion. Grain boundary engineering (GBE) (which works
on the idea of altering the distribution, nature and inter-connectivity
of grain boundary network) is an attractive approach to improve the
resistance to intergranular damage of a polycrystalline materials.
GBE microstructure is usually achieved through thermomechanical
processing involving strain-annealing or strain-recrystallization [1].
In the present study, GBE microstructure was developed in Hastelloy
C-276 (a Ni based superalloy) with a nominal composition of 58%
Ni, 16% Cr, 6% Fe, 11% Mo, 1.2% C, 0.5% V, 0.16% Si, 0.7% Co and
0.2% P through thermomechanical processing. The starting material
consisted of 53% of coincident site lattice (CSL) boundaries and a
grain size of 11 µm. The connectivity of the grain boundaries was
characterized by triple junction analysis with focus on junctions
with 2 or 3 CSL segments (labelled J2 and J3). Thermomechanical
processing involving strain annealing was imposed to achieve GBE
microstructure which increased the CSL boundary fraction to 68%.
Corrosion in oxidizing, reducing and chloride ion atmospheres was
assessed after the GBE treatment via potentiodynamic and
electrochemical impedance tests. A decrease in corrosion rate was
observed in the GBE sample as compared to the initial material
under similar conditions. The presence of carbon and chromium
makes this alloy susceptible to sensitization. The effect of GBE
treatment on sensitization was evaluated by double-loop
electrochemical potentiodynamic reactivation test. The increase in
(J2 + J3) type junctions in the GBE microstructure is expected to
reflect as increase the resistance to sensitization also. The results of
the above tests will be presented in the poster.
[1] V. Randle and G. Owen, Acta Mater. (2006), 54, pp. 1777–1783.
B-3 Microcrack Initiation and its Propagation in Cu metal films on a flexible PI substrate during cyclic-bend testing Atanu Bag, Ki-Seong Park and Shi-Hoon Choi Department of Printed Electronics Engineering, Sunchon National University, Suncheon Jeonnam, Republic of Korea
Cyclic-bend testing of a flexible copper clad laminate (FCCL) was
conducted to investigate microcrack initiation and its propagation in
electroplated Cu metal films on a flexible polyimide (PI) substrate.
During the cyclic-bend testing process, a zigzag pattern of
microcracks was developed perpendicular to the loading direction.
Electron backscattered diffraction (EBSD) was used to perform the
crystallographic orientation mappings of un-deformed (i.e. as-
received) and deformed Cu metal films on the surface planes
following different bending cycles. EBSD analysis revealed an
intergranular type of propagation that was predominant during the
cyclic-bend testing. Most of the microcracks were propagated along
the high angle grain boundaries (HAGBs) instead of the twin
boundaries (TBs). EBSD analysis also revealed that microcracks
tended to propagate into the HAGBs of neighboring grains with a
high Schmid factor (SF).
ABSTRACTS POSTERS C 123
Symposium C: Texture and Microstructure Characterization Symposium Chairs:
Dr. Irene Beyerlein, Department of Mechanical Engineering, University of California, Santa Barbara
Dr. Mukul Kumar, Lawrence Livermore National Laboratory
C-1 Texture Analysis using High Energy Material Science Beam Line (HEMS)@Petra III/Hasylab-Hamburg H.-G. Brokmeier1, Z.Y. Zhong2, M.Z. Salih1, N. Al-Hamdany1, S. Sanamar1, X. Zhou1, R. Bolmaro3, N. Schell4 1Inst. of Materials Science and Engineering, TU Clausthal, Clausthal-Zellerfeld, Germany. 2Chinese Academy of Applied Physics, Mianyang, PR China,3 Inst. de Fisica Rosario, IFIR/CONICET, Rosario, Argentina,4 Helmholtz-Zentrum Geesthacht, GEMS-Outstation DESY, Hamburg, Germany
The high-energy materials science (HEMS) beamline of the
Helmholtz-Zentrum Geesthacht (HZG) is part of the Max von Laue
Hall at Petra III storage ring. An energy range between 30 to 200 keV
is available for diffraction and imaging. While DESY runs one hutch
for hard X-ray experiments, two hutches and the side station were
operated by HZG mainly for engineering materials science
applications. Orientation analysis can be done with a conventional
set up for pole figure measurement including test rig and furnace as
well as with grain mapping obtaining 3DXRD information. The
present contribution deals with conventional pole figure
measurement.
Due to the great advantages of high energy synchrotron radiation
with excellent brilliance and high penetration power pole figure
measurements were carried out measuring texture gradients with a
typical beam size of 100µm x 100µm. Examples of texture gradients
in tubes, severe plastic deformed material, welds and finished
products will be presented. Compared to other methods, pole figure
measurement by synchrotron radiation is fast with excellent
counting statistics, so that ideal conditions for in situ studies exist.
Texture evolution under applied load, compression as well as
tension, or under annealing gives perfect results. Experiments at
different Mg-alloys, shape memory alloys, Al-alloys and Ti-alloys
have been carried out.
Disadvantages of synchrotron radiation are the long elliptical shape
of the pole figure window, the small gauge volume and the extreme
parallel beam. Problems can arise in case of un-sufficient grain
statistics and in some case of inhomogeneous textures distributions.
Means in all cases in which the texture changes during pole figure
measurement.
[1] H.-G. Brokmeier and Sang Bong Yi: Texture and Texture Analysis in Engineering Materials, In: Neutrons and Synchrotron Radiation in Engineering Materials Science, W. Reimers, A. Pyzalla, A. Schreyer, H. Clemens (eds.), Wiley VCH Verlag, Weinheim, 2008, pp.57-77.
C-2 Comparison of preferred orientation of austenite and ferrite phases of duplex steel with rolled single phase austenitic and ferritic steel J. Capek1, M. Cernik2 and N. Ganev1 1Czech Technical University in Prague, Prague, Czech Republic.
2U. S. Steel Kosice, Kosice, Slovakia.
The preferred orientation plays an important role in the various
branches of industry. Preferred orientation result in changing of
material properties depending on the significant direction [1].
In this contribution, the behavior of three type of steel after rolling
were investigated. Particular phases of duplex steel have different
mechanical and thermal properties [2]. Due to their mutual
influence during plastic deformation, it is possible to suppose the
differences between preferred orientations of austenite and ferrite
phases of duplex steel with single-phase austenitic and ferritic steel.
For this reason, the preferred orientation of austenite and ferrite
phases of rolled 1.4470 duplex steel with rolled single phase 1.4301
austenitic and 1.4021 ferritic steel were compared. The 0–50%
reductions of rolled steel plates were selected. Mainly, the strength
and type of preferred orientation in relation to reduction and
material were compared. Moreover, preferred orientation was
investigated by X-ray diffraction and electron back-scattered
diffraction (EBSD).
[1] H. Hu (1974) Texture. 1, 233–258. [2] R. Dakhlaoui, Ch. Braham & A. Baczmański (2007) Mater. Sci.
Eng.: A. 444, 6–17.
C-3 Quantitative Fiber Diffraction: from polymers to composites L. Lutterotti, L. Fambri and M. Bortolotti Department of Industrial Engineering, University of Trento, Trento, Italy.
Fiber diffraction is a specific technique aimed at measuring the
strong texture of polymers or inorganic fibers using an X-ray
transmission setup and a 2D detector. The obtained single shot
image is then analyzed qualitatively to identify the main texture
components from the strong diffraction spots. In this work we aim
to show how the combination of this experimental technique with
the adoption of the standard components inside the Rietveld
Texture Analysis (RTA) [1] can provide a quantification of the sharp
orientation distribution function. With this method, we can follow
the texture evolution of polypropylene or nylon fibers, before and
after thermal and mechanical treatment, quantifying the polymeric
chains dispersion with high accuracy. A more complex case is
represented by the addition of a stiffener like a Smectite or a
Kaolinite to a polymer fiber. In the case of Kaolinite, the modeling
inside the Rietveld is further complicated by the modulated planar
disorder typical of this clay mineral. We will show how the adoption
of a modified single layer approach [2], to account for the
modulated disorder, will help obtaining at once, the full texture of
both phases as well as the strained and highly defective structure of
the Kaolinite. This helps understanding the actual degree of
intercalation inside the fiber to further optimize the composite.
ABSTRACTS POSTERS C 124
The only filtered radiation, used in this experimental setup,
represented an additional problem as relatively strong spots are
visible in the diffraction images due to the sharp texture and
residual Bremsstrahlung. The adoption of the Ebel tube description
[3] is sufficient for the modeling of these extra spots and to solve
elegantly the problem. This opens the question if it would be more
efficient to use non monochromatic radiation, as in a true Laue
camera, to analyze this kind of sharp textures, that make fibers
closer to single crystals than to polycrystalline materials.
[1] L. Lutterotti, M. Bortolotti, G. Ischia, I. Lonardelli and H. -R. Wenk (1997) Z. Kristallogr. Suppl. 26, 125.
[2] L. Lutterotti, M. Voltolini, H. -R. Wenk, K. Bandyopadhyay and T. Vanorio (2010) Am. Mineralogist 95, 98.
[3] H. Ebel (1999) X-ray Spectrometry 28, 255.
C-4 Practical applications of nondestructive texture measurement methods M. Sepsi, M. Benke and V. Mertinger University of Miskolc, Miskolc, Hungary.
The present poster introduces practical applications of new, sample
cutting-free texture measurement methods developed for
centerless X-ray diffractometers. The possibilities offered by the
techniques are shown through practical implementations of the
methods from the field of metal forming, mineralogy and
archaeometry using a certain type of centerless X-ray
diffractometer. The execution of the measurements and the
required minor hardware modifications are also presented.
C-5 Rotation angle optimization for texture measurement using TOF neutron diffraction S. Takajo1, 2 and S. C. Vogel1 1Los Alamos National Laboratory, Los Alamos, USA. 2JFE Steel Corporation, Kurashiki, Japan.
Bulk texture measurements using pulsed neutron diffraction is a
routine application of the HIPPO (High-Pressure-Preferred
Orientation) instrument at LANSCE (Los Alamos Neutron Science
Center), but is also available at GEM/ISIS, iMATERIA/J-PARG or
NOMAD/SNS. Each of these instruments makes use of a vast
detector coverage and typically several rotations are employed to
maximize this coverage. However, to the best of our knowledge, a
tool to optimize the measurement angles to maximize the pole
figure coverage is not available. Here, we describe an approach
employing the General Mapping Tool (GMT) and ImageJ to quantify
the coverage achieved by a given combination of measurements and
rotation angles. Our approach consists of the following steps:
• Measure the detector panels’ positions in the real space and
project them on a two-dimensional plane in an equal area
projection.
• Rotate the projected image by given rotation angles.
• Superimpose all of the rotated images on the initial one and
calculate the area fraction of detector panels.
With this approach, we find that for HIPPO with 45 detector panels
around the diffraction center, covering 40°, 60°, 90°, 120° and 144°
nominal diffraction angles, the pole figure coverage is about 35%.
Through the aforementioned procedure it was clarified that the
coverage for the current standard angle set (0°, 67.5°, 90°) is 67.8%.
The coverage could be increased to 71.5% by adopting the
optimized angle set (0°, 55°, 215°). The method is applicable to any
instrument for which detector coordinates are available.
C-6 ANDES: a multi-purpose neutron diffractometer for the RA10 M.A. Vicente Alvarez1, J.R. Santisteban1, A. Beceyro1, I. Marquez1, S. Gomez, L. Monteros, S. Pincin, A. Glucksberg, A. Coleff2 1Neutron Physics Department, Centro Atómico Bariloche, CNEA. 2Mechancial Division, Centro Atómico Bariloche, CNEA
The Argentinean Atomic Energy Commission (CNEA) is building a
multi-purpose research reactor in Centro Atómico Ezeiza, 30 km
from Buenos Aires Argentina, with commissioning planned for mid
2020. The RA-10 will be an open-pool facility for radioisotope
production, materials and fuel irradiation, silicon doping and
neutron techniques applications. Associated to this last goal there is
a separate project to build the Argentinean Neutron Beams
Laboratory (LAHN), also executed by CNEA and funded by the
National Government. The first stage of LAHN project includes two
instruments of particular application in (nuclear) materials research
and development. One of them is ANDES (Advanced Neutron
Diffractometer for Engineering and Science), a multi-purpose
neutron diffractometer for materials science and engineering
applications, able to perform a variety of analysis, both on intact
objects and on small samples. The techniques available include
strain scanning, texture measurement, and high intensity powder
diffraction on a variety of environments. The development of this
instrument is supported in 4 main areas: shielding design,
mechanical engineering design, neutron optics and automation and
control. In this work we present the advances in the conceptual
design of the instrument.
C-7 Progress on the Development of Texture Analysis Capabilities at the HFIR and SNS at ORNL C.M. Fancher1, J. Bunn1, J. Einhorn2, C. Hoffmann, M.D. Frontzek, and E.A. Payzant1 1Oak Ridge National Laboratory, Oak Ridge, USA. 2University of Virginia, Charlottesville, USA.
Knowledge of the crystallographic preferred orientation of a
polycrystalline material provides critical information needed to both
predict how the material will behave in service, and understand how
and why the material failed in operation. While EBSD and X-ray
techniques are routinely used to quantify texture, these approaches
are surface sensitive. The obtained surface information is not always
representative of the bulk. In contrast, the high penetration nature
of neutrons make them ideal for investigating bulk textures. HIPPO
had served the scientific community since the early 2000s. However,
the loss of the user program at the Lujan center has severely
constrained access to HIPPO. While not specifically designed for
texture analysis, instruments at the HFIR and SNS at ORNL are well
suited to address the needs of the scientific community. This poster
will present recent work on quantifying crystallographic textures in
materials using various instruments at the HFIR and SNS at ORNL.
For example, work at HB2B at the HFIR on additively manufactured
718 Inconel has demonstrated that the processing parameters can
ABSTRACTS POSTERS C 125
be optimized to tune the grain morphology from equiaxed to
columnar, while preserving a 100 fiber texture along the build
direction. A rolled aluminum test sample is being used to develop,
and demonstrate capabilities at NOMAD and TOPAZ at the SNS, and
WAND at the HFIR.
ABSTRACTS POSTERS D 126
Symposium D: Deformation Textures Session: Titanium
Symposium Chairs:
Professor Chadwick Sinclair, Department of Materials Engineering, University of British Columbia
Professor Warren Poole, Department of Materials Engineering, University of British Columbia
Dr. Samantha Daly, Department of Mechanical Engineering, University of California, Santa Barbara
D-1 Refining Statistical Magnesium Twinning Models via Machine Learning A.D. Orme, D.T. Fullwood, I. Chelladurai, C. Giraud-Carrier, T. Colton Brigham Young University, Provo, USA.
Various statistical and probabilistic models have been created to
predict twin events, and related texture evolution, using orientation-
based attributes of magnesium alloy AZ31. Recent work done at
BYU suggests that machine learning algorithms can confirm assumed
correlations, and uncover further details of linkages between
microstructure and twin activity. The machine learning results may
also be considered a predictive model, in and of themselves [1]. This
project uses the results of machine learning models to confirm
whether the statistical models consider all the important factors
that influence deformation behavior. The results of this study will
further establish machine learning as a valuable tool in the study of
material behavior and will propose revisions to current models to
yield them more accurate in future predictions.
[1] A.D. Orme, I. Chelladurai, T.M. Rampton, D.T. Fullwood, A. Khosravani, M.P. Miles, R.K. Mishra (2016) Com Mat Sci. 124, 353-363.
D-2 Simulation for texture formation of both face-centered-cubic metals and body-centered-cubic ones based on rotational symmetry among X[100],Y[010] and Z[001] principal axes H. Masui Teikyo University, Utsunomiya, Japan
The principal axes of X[100], Y[010] and Z[001] are perpendicular to
each other as the three orbits of {±𝑋}, {±𝑌} and {±𝑍} by a
rotational symmetry of mathematical group theory in such way that
component X is not related to Y or Z one another whichever. There is
a conservation quantity in the symmetry. As Taylor proved, crystal
rotates so that slips occurs associating themselves with the
minimum total slip amount.1) The minimum total slip amount in
crystal by Taylor corresponds to both the conservation quantity in
the rotational symmetry of cubic crystal and even Taylor factor M
value itself of the material. It will be demonstrated in this study that
these approaches are useful for both face centered cubic (fcc) metal
and body centered cubic (bcc) one.
1. In fcc metal, distributions in 3D ODF coordinates for Taylor factor
M value i.e. the minimum total slip amount under cold rolling was
calculated based on Taylor’s formidable restriction rule of the five
slips.1) Main results are as follows. In fcc metal, orientation at onset
(minimum) of M value shows the cube {100}<001> and M value
increases gradually {100}<001>→ {100}<016>→{100}<013>→
{100}<012> →{100}<023>→{100}<0,9,11> with decrease of φ1 or
{100}<001>→ {016}<100> →{013}<100>→{0,6,13}<100> with
increase of φ2, most of which were experimentally reported as
indiscrete recrystallized orientations with lowest dislocation density
named the cluster composed of cube and cube-family in fcc metal.
2. In bcc metal, an intersection of two kinds of {110} planes from
the three ones composed of {110}, {101} and {011} is chosen.
Based on the rotational symmetry of the principal axes of X[100],
Y[010] and Z[001] ,72 possible combinations of the five slips on
{110} planes based on Taylor’s formidable restriction rule of the five
slips are calculated among three kinds of intersections of
two {110} planes on ⟨111⟩ direction in bcc metal. Crystal rotation is
carried out by only one solution among the 72 by the minimum total
slip amount at every strain and simulates properly lengthy of
accumulated researcher’s experimental results such as the three
stable orientations of bcc metal in rolling {112}⟨110⟩,
{11 11 8}⟨4 4 11⟩ and {100}⟨011⟩.
[1] G.I. Taylor (1938) J. Inst.Metals 62,307.
D-3 Texture Changes of Electromagnetic Ferritic Stainless Steels by Compressive Deformation at High temperatures Y. Onuki1, S. Sato1, M. Uchida1, T. Naruse2, Y. Kim2, T. Ebata2, S. Fujieda3 and S. Suzuki3 1Ibaraki University, Ibaraki, Japan. 2Tohoku Steel Co., Ltd., Miyagi, Japan. 3Tohoku University, Sendai, Japan.
Precipitation-hardened ferritic stainless steels are used for
electromagnetic actuators of engines, as these steels reveal the high
strength and soft magnetic properties. The hardening of these
ferritic stainless steels occurs by formation of nanoscale precipitates
of NiAl in during aging after solution treatment. Furthermore, it is
required to control the texture of these steels, since it is known that
the soft magnetic properties are obtained in the ferritic steels with
<100> fiber texture. However, texture control of the ferritic stainless
steels has not been attempted so far. In this study, the texture
change in a ferritic stainless steel by deformation at high
temperatures. As it has been shown that the texture of ferritic Fe-Si
alloys is significantly changed by deformation conditions such as
temperature and strain rate [1], the compressive deformation
processes were applied to the texture control of the present
stainless steels.
Samples used were a ferritic steel of Fe-14.5Cr-3Ni-2Mo-1Al-1Si (in
mass%). The specimen for uniaxial compression deformation test
was a cylinder of φ10 x H15mm. They were compressed under
different strain rates at high temperatures between 973 and 1073 K.
The microstructure and texture of the deformed sample were
characterized by analyzing the cross section of the cylindrical
samples using electron backscatter diffraction (EBSD). The volume
ABSTRACTS POSTERS D 127
fractions of <100> and <111> texture components in the sample
were mainly investigated in this work.
The texture analysis results by EBSD showed that the fraction of
<100> texture component increases with decreasing strain rate, and
reveals the maximum in the samples deformed at the strain rate of
5x10-4s-1.
The dependences of microstructure and texture on the deformation
condition seen in the current study is similar to what observed in the
previous studies [1, 2]. Namely, lower density of small angle grain
boundary and higher fraction of <100> oriented region are achieved
with lower strain rate. This suggests the activation of PDGG
(preferential dynamic grain growth). The PDGG is achieved by the
strain-induced grain boundary migration due to the difference of
stored energies between different crystal orientations. Since <100>
has lower Taylor factor than <111>, another deformation texture
component during uniaxial deformation, lower dislocation density in
<001> than in <111> is expected. Therefore, it can be concluded that
<100> oriented grains expands by consuming <111> oriented grains
so that the total stored energy in the bulk is reduced. The current
result indicates that the PDGG can be applied as the texture
controlling mechanism not only in binary or ternary alloys but also in
practical alloy steels including various elements.
[1] Y. Onuki, R. Hongo, K. Okayasu & H. Fukutomi (2013) Acta Mater., 61, 1294.
[2] Y. Onuki, S. Fujieda, S. Suzuki & H. Fukutomi (2017) ISIJ Inter., 57, in press.
D-4 Texture evolution of low carbon steel wires resulted from prior drawing process Athanasios Vazdirvanidis1, George Pantazopoulos1, Marianna Katsivarda2, Avraam Mastorakis3 1ELKEME, Hellenic Research Centre for Metals S.A, 2National Technical University of Athens (N.T.U.A.) - School of Mining & Metallurgical Engineering, 3SIDENOR S.A.
Control of the microstructure of low carbon steel wires is important
in attaining the desired mechanical and formability properties in the
final product. In this frame, ferrite grains size and morphology as
well as texture characteristics play an important role. These
parameters are simultaneously affected by the cross-section
reduction process and the amount of the imposed cold work as well
as the final recrystallization annealing treatment. Examination of
their evolution in the successive wire/rod drawing steps is therefore
considered necessary for understanding and improving the
manufacturing process. In this paper, the microstructure properties
of Ø5.5 - Ø1.5 mm steel wires are examined by optical, scanning
electron microscopy and electron backscatter diffraction. Results
include quantification of grain morphology characteristics, texture
components and discussion, interpretation together with the
evolution of mechanical properties.
D-5 The effect of damping capacity on twinned AZ31 magnesium alloy after heat treatment J.H. Kwak1, J.H. Choi1 C.Y. Kang1 and K.H. Kim1 1Pukyong National University, Busan, Republic of Korea.
The damping capacity of magnesium and its alloys were influenced
by the dislocation mechanism associated with dislocation density,
crystal orientation and grain size. The deformed material which
having a low damping capacity was improved due to heat treatment
by decreasing of dislocation density and increasing of grain size.
However, in this study, decrement of damping capacity was shown
in case of annealed specimen at 623K for 30minutes compared with
before heat treatment despite increasing tendency of damping
capacity. It is expected that the other factor is contributed to
damping capacity. The tensile twin and crystal orientation were
changed by recrystallization in all specimens. It was investigated that
the effect of crystal orientation and twin on damping capacity after
heat treatment. In order to investigate these effects, AZ31
Magnesium alloy was rolled at 673K with rolling reduction of 10%
and 50%, respectively. Damping capacity test specimens were
machined out from rolled plate with perpendicular to the Normal
direction and annealed at various heat treatment conditions. Then,
damping capacity was measured by using internal friction
measurement machine, and microstructure was examined by using
optical microscopy. Texture measurement including of XRD and
EBSD was carried out on damping specimens in order to analyze
crystal orientation distribution. In 50% rolled specimen, larger
fraction of deformation twin was observed than 10% rolled
specimen. The damping capacity of 50% rolled specimen showed
higher value than that of 10% rolled specimen. At the beginning of
the heat treatment, damping capacity was affected by residual twin
fraction, but twin fraction should not affect damping capacity due to
recrystallization with increasing of heat treatment time.
D-6 Texture formation behavior during high-temperature deformation in M1 magnesium alloy K.J. Lee, M.S. Park, J.H Choi and K.H Kim Pukyong National University, Busan, Republic of Korea.
The interest in using lightweight materials in automotive industries
has been recently growing due to reducing weight, and especially
magnesium and its alloy have been paid attention as lightweight
materials because of low density and high specific strength. In
generally, however, magnesium alloys formed a strong basal texture
which affects on mechanical property during high temperature
deformation. Thus, understanding the behavior of texture formation
in high temperature is important for improving formability. Many
researchers found that deformation condition was an important
factor in order to texture control on AZ system magnesium alloy. In
case of M1 magnesium alloy has been investigated in texture
formation resulting from grain size manipulation by precipitation,
but there seem no studies on the texture development during high
temperature on M1 magnesium alloy by deformation condition. In
this study, microstructure evolution and texture formation behavior
is investigated under various deformation conditions in M1
magnesium alloy. In order to make the same initial conditions, M1
magnesium ingot was rolled at 673 K with a rolling reduction of 30%.
Uniaxial compression tests specimens were machined in such a way
that the compression plane was parallel to the rolling plane, and
subsequently annealed at 823 K for 1h. Uniaxial compression tests
were carried out at 723 K under a strain rate ranging from 5.0x10-4s-1
ABSTRACTS POSTERS D 128
to 5.0x10-2s-1 up to a strain of -1.0. EBSD measurement was
performed for observation of crystal orientation distribution. As a
result, occurrence of the dynamic recrystallization and formation of
fiber texture was confirmed in the experimental conditions. The
grain distribution is heterogeneous in all case of the specimens. The
position of maximum axis density of the texture and its intensity
were varied depending on deformation conditions.
D-7 Deformation Behavior of Commercially Pure Titanium (Grade-2) under Uniaxial Compression Devesh Kumar Chouhan, Sudeep Kumar Sahoo, Somjeet Biswas Department of Metallurgical and Materials Engineering, Indian Institute of Technology Kharagpur, West Bengal-721301, India
Commercially pure titanium (CP-Ti) and its alloys are of great
importance in aerospace, permanent bio-implant, chemical and
automobile industries. This is due to its excellent corrosion
resistance and high strength to density ratio. Conventional thermo-
mechanical processes and in specific cases, severe plastic
deformation techniques are used to enhance their mechanical
properties by altering microstructure and crystallographic texture.
CP-Ti has hexagonal close packed (hcp) structure below 1155K.
During plastic deformation; basal<a>, prismatic<a> and pyramidal
{<a> and <c+a>} slip systems could be activated. However, during
room temperature, a major part of the deformation consists of
twins. In this work, deformation behavior of CP-Ti at low strain by
uniaxial compression is studied. The grain refinement mechanism,
evolution of texture and the associated twins and CSL boundaries
are investigated.
ABSTRACTS POSTERS N 129
Symposium N: Mathematical, Numerical and Statistical Methods of Texture Analysis Symposium Chair:
Dr. Oliver Johnson, Department of Mechanical Engineering, Brigham Young University
N-1 Texture Visualization Using Neo-Eulerian Rotation Representations P.G. Callahan1, M. Echlin1, T.M. Pollock1, S. Singh2 and M. De Graef2 1UC Santa Barbara, Santa Barbara, USA. 2Carnegie Mellon University, Pittsburgh, USA.
The texture of a polycrystalline material is usually expressed in
terms of the Bunge Euler angles; an orientation distribution function
(ODF) is then visualized by means of contour plots in planar sections
through the relevant fundamental zone (FZ). With the availability of
large scale orientation data sets obtained from EBSD experiments it
has recently become feasible and useful to consider other rotation
representations, in particular the neo-Eulerian representations,
including the Rodrigues-Frank vector, the quaternion vector, the
homochoric vector, and the 3D stereographic vector. In addition,
the cubochoric representation, a new equal volume mapping of the
unit quaternion hemi-sphere onto a cube, has recently become a
useful representation, especially in the context of dictionary
indexing of EBSD patterns as well as the determination of the ODF
from pole figures via model-based iterative tomographic
reconstruction.
In this contribution, we will begin with a review of the relevant
orientation/rotation representations as well as a detailed
consideration of the graphical visualization, using 3D rendering, of
the crystallographic fundamental zones for all rotational point group
symmetries. Due to the historical importance of the Euler
representation, we will also describe how the Rodrigues-Frank
fundamental zones, which have planar boundaries due to the metric
properties of Rodrigues space, can be mapped into the primary Euler
cell. The Rodrigues FZs of the cyclic rotation groups are represented
in Euler space by prismatic volumes aligned along the 𝜑2 = −𝜑1line;
for rotational groups with multiple rotation axes, the top surface of
this prism acquires a “tented” shape which can be expressed
analytically. Connections to conventional FZ selections in Euler space
will be made, and several basic texture components (cube, Goss,
etc.) will be illustrated in both representations.
We will also apply the new 3D visualization schemes to actual
experimental textures, including a random texture in a Rene 88
alloy, cube and Goss textures in Fe-Si transformer steels, and the
texture of a two-phase alpha-beta Titanium alloy. We will describe
the basic techniques used to obtain the visualizations using open
source rendering programs, as well as a series of open source
routines that can be used to transform lists of Euler angle triplets
into any of the representations described above.
ABSTRACTS POSTERS R 130
Symposium R: Crystallization, recrystallization and growth textures Symposium Chairs:
Dr. Rodney McCabe, Los Alamos National Laboratory
Asher Leff, Department of Materials Science and Engineering, Drexel University
R-1 Recrystallization Texture Evolution of Cold Rolled and Asymmetrically Warm Rolled Austenitic Stainless Steel Sheets S. Umehara1, H. Inoue1 and J. Hamada2 1Osaka Prefecture University, Sakai, Japan. 2Nippon Steel & Sumikin Stainless Steel Corporation, Hikari, Japan.
A {111} texture leads to good deep drawability but does not
generally develop in face-centered cubic metals. One of the authors
previously succeeded in {111} recrystallization texture evolution by
cold rolling, asymmetric warm rolling and subsequent solution
treatment for Al-Mg-Si alloy sheets. In this study, rolling and
recrystallization textures of austenitic stainless steel with low
stacking fault energy have been investigated to reveal whether the
{111} texture can be formed by similar processing. Rolling texture
changes from the α-fiber texture in 70% cold rolled sheets to an
asymmetric texture on the TD axis consisting of {331}<116>-
{111}<112> by additional 40% asymmetric warm rolling, which was
conducted at 873 K using rolls with different diameters.
Correspondingly, pole density at the center of {111} pole figure
increased from 2.16 to 3.18. In addition, microstructural observation
showed that there were two kinds of shear bands inclined at about
30° and 150° to RD on the longitudinal section. One is shear bands
within grains and the other is shear bands passing through a number
of grains. Recrystallization texture after annealing also shows an
asymmetric texture on the TD axis, but consists of {431}<257>-
{331}<116> similar to the α-fiber texture. The 1173 K-1800 s
annealing decreases pole density at the center of {111} pole figure
to 0.78. The 1073 K-3600 s annealing leads to slightly higher pole
density of 1.00 at the center of {111} pole figure. In conclusion, the
rolling texture with near-{111}<112> orientation was obtained in
cold rolled and asymmetrically warm rolled austenitic stainless steel
sheets. However, the recrystallization texture changed to near-
{110}<112> orientation as a main component.
R-2 Effect of Y contents on microstructure and texture evolutions in grain-oriented silicon steel C.S. Park, H.D. Joo, K.S. Han, J.K. Kim and J.T. Park
Steel Product Ⅱ Research Group, POSCO Technical Research
Laboratories, Pohang, Korea.
The microstructure and texture evolutions with various Y contents
were investigated in grain-oriented silicon steel by optical
microscopy and electron backscattering diffraction. As increasing Y
contents, normal grain growth was inhibited during primary
recrystallization and abnormal grain growth was successfully
achieved without any precipitates such as AlN and/or MnS after
secondary recrystallization. Especially, when the Y content was more
than 0.05 wt%, the abnormally grown grains had Goss orientations
and the magnetic flux density of the sheets at 1000 A/m was higher
than 1.8 tesla. The changes of microstructure and texture evolution
are thought to be due to solute segregation of Y atoms at the grain
boundaries.
R-3 The effect of an intermediate heat treatment during thermomechanical controlled processing on recrystallization and subsequent deformation-induced ferrite transformation textures in microalloyed steels P. Gong, B.P. Wynne, W.M. Rainforth Department of Materials Science and Engineering, The University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, S1 3JD, UK
The evolution of texture components for two experimental 0.06 wt%
C steels; one containing 0.03 wt% Nb (Nb steel) and the second
containing both 0.03 wt% Nb and 0.02 wt% Ti (Nb-Ti steel) was
investigated following a new thermomechanical controlled process
route, comprising first deformation, rapid reheat to 1200°C and final
deformation to various strains. Typical deformation textures were
observed after first deformation for both steels. Following
subsequent reheating to 1200°C for various times, the
recrystallisation textures consisted primarily of the α-<011>//RD
texture fiber with a weak -{111}//ND texture fiber, similar to
deformation textures, indicative of the dominance of a strain-
induced boundary migration (SIBM) mechanism. The texture
components after finish deformation were different from the rough
deformation textures, with a strong α-<011>//RD texture fiber at the
beginning, and then the strong peaks move to (111)<12 1> and
(111)<1 1 2> textures due to the deformation-induced ferrite (DIF)
transformation. The effect of Ti on the recrystallisation textures and
deformation textures has also been analysed in this study. The
results illustrate that Ti significantly influences the -{111}//ND
texture fiber. Finally, the textures after deformation and
recrystallisation in the austenite were calculated based on the K-S
orientation relationship between austenite and ferrite. This allowed
the understanding of the mechanism of recrystallization between
first and finish deformation, and the deformation induced ferrite
textures during phase transformation.
ABSTRACTS POSTERS T 131
Symposium T: Transformation Textures Symposium Chair:
Dr. Michael Roach, Biomedical Materials Science, University of Mississippi Medical Center
T-1 Effect of strain-induced martensitic transformation on texture evolution in cold-rolled Co-Cr alloys S. Sato1, M. Nakagawa1, Y. Onuki2, K. Yamanaka3, M. Mori4, A. Hoshikawa2, T. Ishigaki2 and A. Chiba3 1Graduate School of Science and Engineering, Ibaraki University, Hitachi, Japan. 2Frontier Research Center for Applied Atomic Sciences, Ibaraki University, Tokai, Japan. 3Institute for Materials Research, Tohoku University, Sendai, Japan. 4Department of Materials and Environmental Engineering, National Institute of Technology, Sendai College, Natori, Japan.
Co-Cr alloys exhibit high tensile strength with good elongation and
excellent corrosion-resistance properties and hence have been used
in many biomedical uses such as stents and artificial hip joints.
However, the difficulty in plastic deformation limits the application
of the alloys. The plastic deformability of the Co-Cr alloys is
depressed by the strain-induced martensitic transformation (SIMT),
which originates from low stacking fault energy of these alloys, and
the distinct increase in dislocation density in the matrix phase. Since
these microstructural evolution accompanies with the texture
evolution, it is crucial to understand the relationship among the
SIMT, the increase in dislocations, and the texture evolution. To
characterize the evolution of the texture, SIMT, and dislocations, we
evaluated the phase fraction of the martensitic phase and
dislocation density by using time-of-flight neutron diffraction at
iMATERIA beamline in J-PARC. The cold-rolled sheets of Co-29Cr-
6Mo (CCM) and Co-20Cr-15W-10Ni (CCW) alloys were investigated
in this study. While the stacking fault energies of these Co-Cr alloys
are low enough to propagate the SIMT at room temperature, the
stacking fault energies of the CCM and CCW alloys are negative and
positive, respectively, at room temperature. Namely, the SIMT is
expected to proceed more preferentially in the CCM than the CCW
alloy. The volume fraction of martensitic phase (HCP) was
determined by Rietveld-texture analysis with the use of the MAUD
program. As expected from the stacking fault energies, the SIMT
progressed at a small rolling reduction of 10% in the CCM alloy,
whereas the volume fraction of the martensitic phase was almost
zero up to the rolling reduction of 20% in the CCW alloy and
increased rapidly from the rolling reduction of 30%. The texture of
the matrix phase (FCC) of the CCM and CCW alloys gradually
developed in a similar manner, whereas the martensitic phase had
strong texture even at small rolling reduction. This may be because
the martensitic phase formed selectively from grains with specific
crystallographic orientations. To evaluate the dislocation density,
the line-profile analysis was also carried out on the high-resolution
diffraction data obtained from the backscatter detectors. The
dislocation density of the matrix phases of the CCM and CCW alloys
increased similarly with an increase in the rolling reduction. These
microstructural characteristics suggest that the difference in
deformability between the CCM and CCW alloys originate not from
the strain hardening of the matrix phase but from the growth
behavior of the martensitic phase.
T-2 Characterization of the Factors Influencing Retained Austenite Transformation in Q&P Steels via EBSD Analysis D. Adams¹, D. Fullwood¹, J. Cramer¹, S. Irfan¹, H. Evanson¹, T. Mathis¹, S. Cluff¹, M. Miles¹, E. Homer¹, T. Brown², R. Mishra², and B. Kubic² ¹Brigham Young University, Provo, USA. ²General Motors, Warren, USA.
A recent push for more fuel-efficient vehicles by the automotive
industry has encouraged an increased focus on formable Advanced
High-Strength Steels (AHSS). These steels are of particular interest
due to their unique combination of high strength and ductility,
which allows them to provide the necessary strength to reduce
weight requirements in certain parts of an automobile. The
particular AHSS of interest in this study rely on the Transformation
Induced Plasticity (TRIP) effect, in which a minority fraction of
retained austenite (RA) grains in the steel transform to the stronger
martensite phase as the steel is plastically deformed, providing extra
ductility via the transformation event. Understanding the factors
involved in RA transformation is therefore key to being able to
optimize the microstructure of these steels. This research seeks to
increase understanding of the correlations between microstructure
and RA transformation in TRIP AHSS steels. Through in-situ tensile
tests combined with EBSD and FSD scans, local strain maps at the
micro-scale can be created and analyzed with DIC software. With
this information, it is hoped that the questions of when and why
transformation occurs and the benefits of that transformation can
be answered. Once the answers to those questions are understood,
an improved model of the transformation can be created and allow
for optimization of these advanced materials.
ABSTRACTS POSTERS W 132
Symposium W: A Celebration of the Contributions of Rudy Wenk Symposium Chairs:
Dr. Lowell Miyagi, Geology & Geophysics, University of Utah
Dr. Pamela C. Burnley, Department of Geoscience, University of Nevada, Las Vegas
Dr. Sven Vogel, Los Alamos National Laboratory
W-1 Texture and fracture anisotropy in shales deformed in a deformation DIA Jeff Gay1, Waruntorn Kanitpanyacharoen2, Michael Jugle1, Julien Gasc3-4 Tony Yu4, Yanbin Wang4, and Lowell Miyagi1 1Department of Geology and Geophysics, University of Utah, Salt Lake City, UT U.S.A. 2Department of Geology, Chulalongkorn University, Bangkok Thailand. 3Laboratoire de Géologie, École Normale Supérieure-CNRS, UMR8538, Paris France. 4Center for Advanced Radiation Sources, The University of Chicago, Chicago, IL U.S.A.
Understanding the link between micro and macro scale properties in
earth materials has become increasingly important in geophysical
research. Texture in shales is responsible for much of the seismic
anisotropy that is observed in sedimentary basins. The interaction
between texture and facture anisotropy is critical for assessing
viability of shale as a cap rock in conventional reservoirs, as a
potential source rock for production of natural gas in
unconventional reservoirs, or as target for nuclear sequestration.
Here we deform shales to failure at high pressure and temperature
using the deformation DIA (D-DIA). The D-DIA allows the user to
separate hydrostatic and deviatoric stresses and can be used to
deform samples under high pressure and temperature in both
compression and extension. The D-DIA was originally designed to
generate pressures in excess of several GPa in order to study
deformation behavior of materials at mantle conditions. However,
since there are no conventional crustal rheology devices available at
synchrotron beamlines we use a novel polyether ether ketone
(PEEK) cell assembly to generate reduced pressures of 100-300 MPa
at temperatures of 100-200°C, conditions appropriate for moderate
to deep shales. In-situ texture development, lattice strain evolution,
failure onset, and macrostrain are measured using radial
synchrotron x-ray diffraction and radiography. Texture information
is extracted using the Rietveld method as implemented in the
software program Materials Analysis Using Diffraction (MAUD). The
use of this “low pressure” cell assembly in the D-DIA opens the
possibility to deformation experiments at crustal conditions using
synchrotron x-rays to measure in-situ texture development and
rheological properties.
W-2 In situ texture measurements at high-pressure and high temperature using double-sided laser heating in a radial diffraction diamond anvil cell at ALS beamline 12.2.2 M. Kunz1, J. Yan2, Alastair MacDowell1, Lowell Miyagi3 and H.R. Wenk4 1Lawrence Berkeley Lab, Berkeley, California. 2UC Santa Cruz, Santa Cruz, California. 3University of Utah, Salt Lake City, USA. 4UC Berkeley, Berkeley, California.
Determining the texture throughout the interior of the Earth is
important to understand seismic profiles of the Earth and to
quantify the large scale convection of the Earth’s mantle, which in
turn is linked to the motor of plate tectonics. The study of texture in
rocks and minerals at conditions of the lower mantle or even core
requires diamond anvil cells (DAC’s) as pressure device. The use of
DAC’s for in situ texture measurements was developed to a large
part by Rudy Wenk and co-workers [1-3]. The main criticism of initial
work was that experiments were performed at room temperature
and therefore were irrelevant for processes that happened in the
lower mantle. This was overcome by two approaches 1) an in situ
single-sided laser heating set up [4] co-designed by the Wenk group
and implemented at the ALS and 2) a resistively heated radial
diffraction DAC [5] at DESY. Axial temperature gradients and limited
maximal temperatures are draw-backs of these approaches A
double-sided in situ laser heating set-up based on the laser and
pyrometry optics mounted on a rotational stage was proposed at
HPCAT [6] but never implemented.
In this contribution, we present the implementation of in-situ
double-sided laser heating compatible with radial X-ray diffraction
for texture measurements at beamline 12.2.2 of the Advanced Light
Source (ALS) at Lawrence Berkeley Lab (LBL). The system builds on
the existing, newly built axial set up including peak scaling
pyrometry. Laser and imaging paths are redirected in the horizontal
plane from a 0°/180° direction to a 90°/270° setting. The 90°
redirection involves the insertion of a small periscope mirror pair
with an objective lens into the axial downstream beam path. This is
fully motorized and can be achieved remotely. The 270° beam path
on the other hand involves the removal of the upstream axial
objective lens and the manual installation of a small rig carrying 2 IR
mirrors and the objective lens. Installation and alignment is straight
forward and fast. For temperature measurement, we employ the
peak scaling method also implemented on the axial laser heating set
up. This allows recording 2-dimensional temperature maps and thus
temperature gradients in quasi real time.
Examples of in-situ texture measurements at high pressure and high
temperatures will be presented.
[1] S. Merkel, H.R. Wenk et al. (2002) J. Geoph. Res.107 (B11), 2271, doi:10.1029/2001JB000920.
[2] H.R. Wenk, S. Mathies et al. (2000) Nature 405 1044, doi:10.1038/35016558.
[3] H.R. Wenk, S. Cottaar et al. (2011) Earth Planet Sci Let 306 33, doi:10.1016/j.epsl.2011.03.021.
[4] M. Kunz, W.A. Caldwell et al. (2007) Rev. Sci. Instrum. 78, 063907, doi:10.1063/1.2749443.
[5] H-P. Liermann, S. Merkel et al (2009) Rev. Sci. Instrum. 80 104501, doi:10.1063/1.3236365.
[5] Y. Meng, G. Shen and H.K. Mao (2006) J. Phys.: Condens. Matter 18 S1097, doi:10.1088/0953-8984/18/25/S17.
ABSTRACTS POSTERS W 133
W-3 CPO patterns of an upper crustal shear zone – examples from the Lancinha Fault System, southern Brazil T. Conte1, G.C.G. Cavalcante1, L.E. Lagoeiro1, C.S. Silveira1, K.T. Pesch1, and R. Santos1. 1UFPR – Universidade Federal do Paraná, Curitiba, Brazil.
Crustal deformation processes are related to the rheological
behaviour, which is controlled by mineral constituents, temperature
and pressure conditions, as well as strain rate and fluid assistance.
Upper crustal deformation is dominated by cataclastic flow and low
temperature dislocation creep, often associated with bulging and
subgrain rotation recrystallization. The Lancinha Fault System (LFS),
located in the southern part of the Ribeira Belt, is a Neoproterozoic
dextral strike-slip shear zone trending NE, which extends over ~150
km separating the Apiaí and Curitiba terranes. The southern Ribeira
belt is limited to the north by the Paranapanema craton and to the
south by the Luís Alves craton. The Ribeira Belt was formed as a
result of the collision between the São Francisco, Congo and
Paranapanema cratons during the amalgamation of west Gondwana
at ~600 Ma. Three samples representing quartzites, S-C type schists
and mylonites that crop out along the LFS area were analysed by the
SEM-EBSD technique, and the data were processed using the Mtex
toolbox in MatLab. Thermobarometry studies suggest that these
rocks were deformed under greenschist facies conditions (~300 -
350°C). The rocks are composed mainly of quartz, feldspar,
plagioclase and mica, distributed along anastomosing cleavage
surfaces. Quartz in all samples exhibits ribbon shapes with aspect
ratios up to 7:1, subgrain boundaries, new grains formed by bulging,
and undulose extinction. Samples collected close to the LFS display
J-index ranging from 6.20 to 35.31, while the quartzite sample
located further shows a J-index of 2.85, which suggests that the CPO
(crystallographic preferred orientation) fabric strengthens close to
the shear zone, probably due to an increase in strain. A peak at 60˚ is
observed in the misorientation angle diagram of the mylonite and
the schist located close to the LSF, whereas a peak at low angle
(<10˚) occurs for the quartzite far from the shear zone. The peak at
60˚ is related to dauphiné twinning, while the low angle peak
corresponds to the formation of subgrains. The quartzite and the
schist display quartz c-axis oriented parallel to Z (pole to the
foliation) and a-axis parallel to X (stretching lineation), suggesting
the activation of the basal <a> slip system. A secondary
concentration of rhomb planes close to Z suggests that activation of
rhomb <a> also occurs during the quartzite deformation. Activation
of such slip systems is consistent with the low temperature
microstructure observed in these samples, and suggests that
dislocation creep deformation mechanisms are dominant. The CPO
fabric of the mylonite shows a strong maximum of quartz c-axes
close to X. Such c-axis orientation may be a result of oriented
growing of the quartz grains, since the mylonite microstructure is
typically of low temperature deformation associated with bulging
and subgrain rotation recrystallization, and therefore inconsistent
with the activation of high-temperature slip systems such as prism
<c>. Our results show that low-temperature deformation in shear
zones may be controlled by the dominant recrystallization
mechanism and by preferred growth of quartz. To what extent these
mechanisms depend on local conditions (fluid, strain rate, etc) is not
clear, and future work on similar shear zones should be performed
for comparison.
W-4 Microscale strain partitioning during high-temperature deformation of plagioclase: an example from gabbro-norite of the Barro Alto Complex, Brazil central C.S Silveira¹, L.E. Lagoeiro¹, G.C.G. Cavalcante¹, P.F. Barbosa², F.O. Ferreira³, T. Conte¹, R. Santos¹ M.T.F. Suita4 ¹Universidade Federal do Paraná, Curitiba, Brazil; ²Univesidade de Brasília, Brasília, Brazil;³ Universität Bayreuth, Bayreuth, Germany ; 4Universidade Federal de Ouro Preto, Ouro Preto, Brazil.
Microstructures and textural analysis are essential to evaluate
aspects related to plastic deformation in minerals of the crust,
especially for abundant minerals such as plagioclase. In this work,
we analyzed metamorphosed gabbro-norites from the mafic-layered
complex Barro Alto, with the purpose of understanding the
development of preferred orientation in plagioclase by optical and
electron microscopy associated with the EBSD technique. The Barro
Alto complex is a continental-scale feature exposed in the Brasília
Belt, which belongs to Tocantins Structural Province, Brazil Central.
This complex was formed by mafic-ultramafic layered intrusions
mylonitized and metamorphosed under granulite facies conditions.
The samples are composed of porphyroclasts of plagioclase and
diopside in a matrix dominantly composed of plagioclase,
clinopyroxene, orthopyroxene and, less commonly, amphibole and
biotite. We separated the samples in two groups according to the
matrix grain size. Group A comprises three samples with a very fine-
grained mylonitic matrix (0.03 to 0.08 mm) which wrap around
porphyroclasts. The Group B has one sample composed mainly by
medium-grained plagioclase (1 to 0.5 mm). Both groups shows
composition segregation into felsic and mafic bands, mechanical
twinning, undulose extinction and recrystallization of plagioclase
grains. In Group A, the plagioclase poles figures for {100}, {010} and
{001} show a weak texture with a low J index (2.4). In Group B, pole
figures exhibit maximum in {100} parallel to X direction and {010}
parallel to Z direction. The strongest texture for the pole figures is
confirmed by the high J index (15.33). The microstructure and
texture analyses suggest that different deformation mechanisms
were active in each group. The weak texture observed in Group A
may be a result of diffusive processes in fine-grained aggregates. On
the other hand, in coarser-grained domains dislocation creep may
dominate, which led to the development of stronger texture. In
Group B the principal mechanism is dislocation creep controlled by
the [100](010) slip system. These results are consistent with high-
grade deformation conditions of the Barro Alto Complex.
Differences in grain size suggests a strong partitioning of
deformation between diffusive processes (grain size sensitive
mechanism) in fine grained aggregates, and dislocation creep in
large grains aggregate.
ABSTRACTS POSTERS W 134
W-5 Application of the Elasto-Viscoplastic Self Consistent (EVPSC) code to modeling texture and lattice strain evolution in periclase
F. Lin1, N. Hilairet2, S. Merkel2, J. Immoor3, H. Marquardt3, C. Tomé4 and L. Miyagi1 1Department of Geology and Geophysics, University of Utah, Salt Lake City, 84112, USA. 2Unité Matériaux et Transformations, Université Lille 1 - CNRS - ENSCL, Villeneuve d'Ascq, France. 3Bavarian Research Institute of Experimental Geochemistry and Geophysics, University Bayreuth, 95440 Bayreuth, Germany. 4Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
Seismic anisotropy is observed in many regions of the deep earth. It
is believed that this is due to texture (crystal preferred orientation)
development as a result of plastic deformation of minerals by
dislocation glide and climb. Ferropericlase is the second most
abundant phase in the Earth’s lower mantle. Thus, understanding
the deformation mechanism of ferropericlase minerals is important
to interpret anisotropy in the Earth’s lower mantle. In this study,
deformation of a periclase was performed in the Deformation-DIA
(D-DIA) at the European Synchrotron Radiation Facility (ESRF)
beamline ID06. A polycrystalline sample was deformed at ~5.4 GPa
and ambient temperature to a total strain of ~0.37 at average strain
rates of 9.52e-6/s, 2.26e-5/s and 4.30e-5/s. Lattice strains and texture
were recorded using in-situ synchrotron x-ray diffraction. Lattice
strains were extracted using Multi-fit/Polydefix and texture
information were obtained by Rietveld texture analysis using the
software package Materials Analysis Using Diffraction (MAUD).
During deformation, lattice strains on {200} showed an increase in
strain early in deformation followed by a rapid decrease upon
continued deformation. This initial peaking of lattice strain may due
to pinning from carbon contamination introduced during sintering of
the sample prior to deformation. Lattice strains on {200} are
significantly smaller than lattice strains on {111} and {220}. Lattice
strains on {220} are slightly larger than those on {111}. Texture
development is characterized by {001} planes becoming oriented at
high angles to compression. Here we used the Elasto-Viscoplastic
Self-Consistent (EVPSC) method to simulate lattice strains and
texture evolution as a function of slip systems activities. Parameters
such as critical resolved shear stress (CRSS) for the various slip
systems, strain hardening, initial grain shape and Inclusion-Matrix
interaction assumption were modified in order to optimize the
simulation. We obtained a good fit to the experiment with dominant
{110}<1-10> slip and a parabolic strain hardening. This illustrated
the utility of EVPSC to understand deformation of materials at high
pressures.
W-6 Deformation of two-phase polycrystals under high pressures: effect of phase proportions on in-situ textures and stress partitionning in olivine + antigorite N. Hilairet1, T. Ferrand2, P. Raterron1, S. Merkel1, A. Schubnel2, J. Guignard3*, C. Langrand1, W. Crichton3 1CNRS - Université de Lille - ENSCL, 59000 Lille, France. 2CNRS - ENS, 75005 Paris, France. 3European Synchrotron Radiation Facility, 38000 Grenoble, France. *now at Observatoire Midi-Pyrenées, 31400 Toulouse, France
Serpentinization is expected to occur when fluids are released from
the dehydrating subducting slabs and migrate into shear zones and
the mantle wedge formed of peridotite. At shallow depths (15-
30km) a few percent volume serpentine can induce strain
localization and strongly textured domains in peridotite bodies.
Aggregate seismic velocities as a function of microstructure and
serpentine proportion have been investigated by several studies.
Less is known on mechanical properties and seismic velocities of
deformed peridotites containing antigorite in deeper contexts.
Antigorite and olivine both have (very) anisotropic single crystal
elastic properties, which for a mixed aggregate may result in several
types of large scale seismic velocities anisotropies in subduction
zones. These seismic velocities will be highly dependent on
deformation mechanisms and on the texture and microstructure of
the aggregate, which are expected to evolve as a function of strain
and serpentine proportion. Here we investigate the rheology and
textures of antigorite + olivine « synthetic » peridotites with varying
serpentine content (5 to 50%) at high pressure (2- 3 GPa, ca. 60-90
km depth), using the D-DIA large volume press and synchrotron
powder X-ray diffraction and imaging. The results will provide
insights on the conditions under which serpentinized peridotites
evolve in a regime dominated by the rheology of the strongest
phase (olivine) or the weakest phase (antigorite). This study will
further help refine our knowledge of the serpentinized peridotites
seismic velocities at depths, taking into account potential
deformation mechanisms variation with phase proportions.