X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok...

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X-ray Diffraction and EBSD Jonathan Cowen Swagelok Center for the Surface Analysis of Materials Case School of Engineering Case Western Reserve University October 27, 2014

Transcript of X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok...

Page 1: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

X-ray Diffraction and EBSD

Jonathan Cowen

Swagelok Center for the Surface Analysis of Materials

Case School of Engineering

Case Western Reserve University

October 27, 2014

Page 2: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

Outline

• X-ray Diffraction (XRD)• History and background• Introduction to XRD• Practical applications

• Electron Back-Scattered Diffraction (EBSD)• Introduction to EBSD• Types of information that can be drawn from EBSD

Page 3: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

• Wilhelm Conrad Röntgen– 1895: Discovery of X-ray– 1901: awarded first Nobel prize winner for Physics

• M.T.F. von Laue: – 1912: Discovery of the diffraction of X-rays by

single crystals , in cooperation with Friedrich and Knipping

– Terms: Laue equation, Laue reflections– 1914: Nobel prize for Physics

• W.H. and W.L. Bragg: – 1914: X-ray diffraction and Crystal Structure– Terms: Bragg‘s equation, Bragg reflections– 1915: Nobel prize for Physics

Discovery of X-rays and Modern XRD

Page 4: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

Anode

X-raysCathode

e-

Wavelength (Å)

Inte

nsity

Kα=1.54Å

Kβ=1.39Å

X-ray Generation

The emission spectra for Cu

Page 5: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

Monochromatic Radiation is needed for Crystal Structure Analysis

The dotted line is the Mass Absorption coefficient for Ni

λ(Å)Unfiltered

λ(Å)Ni Filter

1.2 1.4 1.6 1.8 1.2 1.4 1.6 1.8

Inte

nsity

Mas

s Abs

orpt

ion

Coe

ffic

ient

Filters for Suppression of Kβ Radiation

Page 6: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

Interference and Bragg’s Law

AO=OBBragg Diffraction occurs when 2AO=nλSinθ=AO/d(hkl)2d Sinθ=nλ

λ=wavelength of the incident radiation

Cu Kα=1.54 Å

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Monochromatic X-rays using Diffraction

C (Graphite)

Graphite monochromator utilizes a highly orientated pyrolytic graphite crystal (HOPG) mounted in a compact metal housing to provide

monochromatic radiation. This is usually an improvement over filters.

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Bragg’s Law

Knowing dhkl we can calculate the lattice

parameters

Lattice Parameter CalculationMiller Indices

Silicon Powder

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Scintag Advanced X-Ray Diffractometer System

Conventional theta-theta scanRocking curves and sample-tilting

curvesGrazing angle X-ray diffraction

(GAXRD)DMSNT software package is used to

control the diffractometer, to acquire raw data and to analyze

data.PDF-2 database and searching software for identifying phases

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• Amorphous patterns will show an absence of sharp peaks• Crystalline patterns will show many sharp peaks

• The atoms are very carefully arranged• High symmetry

• From peak locations and Bragg’s Law, we can determine the structure and lattice parameters. • Elemental composition is never measured• By comparing to a database of known materials, phases can be identified

Amorphous Pattern Crystalline Pattern

X-ray DiffractionTypical Patterns

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X-ray DiffractionPeak Intensities

1. Polarization Factor

2. Structure Factor

3. Multiplicity Factor

4. Lorentz Factor

5. Absorption Factor

6. Temperature Factor

α-Al2O3

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X-ray DiffractionPhase Identification

Iron Chloride Dihydrate

• The PDF-2 (Powder Diffraction File) database contains over 265K entries.• Modern computer programs can determine what phases are present in any sample by quickly comparing the diffraction data to all of the patterns in the database.• The PDF card for an entry contains much useful information, including literature references.

International Centre for Diffraction Data (ICDD)

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X-ray DiffractionPhase Identification

Iron Chloride Dihydrate

PDF # 72-0268 Iron Chloride Hydrate

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X-ray DiffractionQuantitative Phase Analysis (QPA)

• External standard method• A reflection from a pure component.

• Direct comparison method• A reflection from another phase within

the mixture.• Internal standard method

• A reflection from a foreign material mixed within the sample.

• Reference Intensity Ratio (RIR)• Generalized internal standard method

developed by the ICDD.Breakdown of the PDF-2 database

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X-ray DiffractionQuantitative Phase Analysis (QPA)

DIFFRAC.SUITE EVA

Fe 75, Ni 25 wt.%

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X-ray DiffractionX ray diffraction of semi-crystalline polymer and amorphous

polymer

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X-ray DiffractionXRD is a primary technique to determine the degree of crystallinity in

polymers.

The determination of the degree of crystallinity implies use of a two-phase model, i.e. the sample is composed of crystalline and amorphous regions.

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Smaller Crystals Produce Broader XRD Peaks

Note: In addition to instrumentalpeak broadening, other factors that contribute to peak broadening include strain and composition inhomogeneities.

Gold Nanoparticle

2nm

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When to Use Scherrer’s FormulaCrystallite size < 5000 Å

BcosBKt

θλ

∗∗

=

t = thickness of crystalliteK = constant dependent on crystallite shape (0.89)λ = X-ray wavelengthB = FWHM (full width at half max) or integral breadthθB = Bragg angle

Page 21: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

Residual Stress Measurements using X-Ray Diffraction

Page 22: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

PolycrystallineSample

X-ray DiffractionDiffraction cones arise from randomly oriented

polycrystalline aggregates or powders

X-ray

Diffraction Cone forms Debye Rings

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Area Detector

X-ray Diffraction2D Detector

Debye Rings

Page 24: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

X-ray DiffractionTypes of Detectors

Small portion of Debye ring acquired

scan necessary long measuring times

large 2θ and chi range measured simultaneously

measurement of oriented samples very short measuring times intensity versus 2θ by integration of

the data

2D Area detectorScintillation detector

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• Small Beam diameter• Can achieve 200μm

• Parallel Illumination• Forgives displacement errors

• 4 circle Huber goniometer• Dual beam alignment system

X-ray DiffractionBruker D8 Discover

Page 26: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

Polymers, due to their long chain structure, are often highly oriented.

X-ray DiffractionOrientation

Alignment of a sample in a drawing process causes

orientation effects

Page 27: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

X-ray DiffractionOrientation

The intensity distribution of the Debye ring reveals much information about the texture of the material being studied!

Page 28: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

In addition to identifying the CaCO3 as the Aragonite polymorph, X-ray diffraction patterns reveal a strong degree of crystallographic texture in the intact shell.

X-ray Diffraction of Conch Shells

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X-ray DiffractionOrientation

Simulated pattern of CuInSe2

Acquired XRD pattern of a thin film of CuInSe2grown on a Mo foil substrate

101

112

103

211

213

204

224

112

213

204

Page 30: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

X-ray Sources

Anode Kα1(Å) Comments

Cu 1.54060 Best for inorganics. Fe and Co fluorescence.

Cr 2.28970High Resolution for large d-spacing. High attenuation

in air.

Co 1.78897 Used for ferrous alloys to reduce Fe fluorescence.

Rigaku D/MAX 2200 Diffractometer

Page 31: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

X-ray DiffractionSummary

• Structure Determination• Phase Identification• Quantitative Phase Analysis (QPA)• Percent Crystallinity• Crystallite Size and Microstrain• Residual Stress Measurements (Macrostrain)• Texture Analysis• Single Crystal Studies (not a SCSAM core

competency)

Page 32: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

Electron Diffraction Zeiss Libra 200EF

Polycrystal

Single Crystal

Page 33: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

EBSD – Electron Back-Scattered Diffraction in the SEM

Raw PatternAveraged BackgroundBackground Corrected Pattern

Page 34: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

1

2

10

12 4

EBSD – Electron Back-Scattered Diffraction in the SEM

Background Corrected Pattern Indexed Pattern

Page 35: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

300×300 grid

5 μm step

Analysis time: 36 minutes

500 μm

EBSD data – MapsBeam scan provides orientation map of polycrystalline NaCl

The colors indicate specific orientations

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polycrystalline Al2O3

EBSD data – Maps

Page 37: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

A single automated EBSD run can provide a complete characterization of the microstructure:

• Phase distribution• Texture strength• Grain size• Boundary properties• Misorientation data• Slip system activity• Intra-granular deformation• Can collect XEDS simultaneously

Page 38: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

bcc Fe fcc Fe

bcc Fe fcc Fe

EBSD Phase Discrimination

Differences in interplanar angles and spacings allow similar-looking EBSD patterns from bcc and fcc Fe to be readily distinguished.

Page 39: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

Phase distribution, texture, grain size / shape, boundary properties, misorientation, slip system activity, intra-granular deformation....

EBSD data – Maps

Orientation bcc

Orientation fcc

Phase map

Page 40: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

Summary• XRD is a powerful tool for answering some specific questions

about a given sample.– Phases present, QPA, orientation, residual stress, texturing, and

crystallite size analysis.

• XRD is extremely efficient for the characterization of samples.– Sample preparation time is minimal when compared to SEM/EBSD

and TEM.– Data acquisition is straight forward and short set up times are required.

• XRD will provide a larger sampling area and a more accurate averaged result of the lattice parameter, but EBSD will be more site specific.

• EBSD yields similar results and all the same “specific questions” can be answered in one data set!

Page 41: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

Hough Transformation

1

2

10

12

4

12

10

4

12

-90°

90°

Hough transformation Transforms x-y space to ρ−θ space. Bands in Hough space show as points which are easier to identify and extract relative angles.

Page 42: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

Format of Crystal Information

Euler Angles using Bung convention:1. A rotation of φ1 about the z axis

followed by2. A rotation of ϕ about the rotated x-

axis followed by3. A rotation of φ2 about the rotated z-

axis

Solution #

# votes

Ban

d tr

iple

ts

S3 (best solution w/most votes)S2 (2nd best solution w/ 2ndmost votes)

Page 43: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

X-ray DiffractionPhase Identification

Page 44: X-ray Diffraction and EBSD · PDF fileX-ray Diffraction and EBSD. Jonathan Cowen. Swagelok Center for the Surface Analysis of Materials. Case School of Engineering. ... X-ray Diffraction.

λ(Å)Unfiltered

λ(Å)Ni Filter

1.2 1.4 1.6 1.8 1.2 1.4 1.6 1.8In

tens

ity M

ass A

bsor

ptio

n C

oeff

icie

nt