Development of High Temperature ODS Alloys for Additive ... · lower milling times compared to...
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Development of High Temperature ODS Alloys for Additive Manufacturing of Aerospace Structural Components Aaron Beckley, Michael Bodziak, Cole Davis, Philip Gordon, Monica Viers Faculty Advisors: Dr. Eric P. Kvam Industrial Sponsors: Dr. David Ellis, Laura Evans Project Background Powder processing parameters were explored to incorporate yttria particles into NiCrAl powder for use as an oxide dispersion-strengthened (ODS) alloy in additive manufacturing. Orbital and attritor milling were used. Particle size analysis, SEM, and specific surface area measurements showed that many cycles of particle welding followed by fracture occurred during orbital milling. Compared to orbital milling, attritor milling resulted in faster welding and fracture cycles. EDS revealed that yttria powder was evenly dispersed onto NiCrAl particle surfaces during milling. Experimental Procedure Results & Discussion Future work Results & Discussion (cont.) MSE 430 - 440: Materials Processing and Design This work is sponsored by NASA Glenn Research Center in Cleveland, OH. • Analysis of milling time for the planetary ball mill should be explored, to fill in intermediate times. • Examination of an increased milling speed to further reduce time while maintaining similar trends. • Investigate potential oxidation in milling via X-Ray Diffraction. • Cross-sectional examination to determine yttria dispersion in the core of the particles. • Cycling through large and small average diameter in both methods • Two sizes of particles form with attrition milling • Attrition milling takes place over 1/10 the time Acknowledgements Thank you to Dr. Eric P. Kvam, Dr. David Ellis, Laura Evans, Dr. Quynhgiao Nguyen, Henry DeGroh, and David Scannapieco for their guidance and assistance with this project. Conclusions • Multiple cycles of welding and fracture were observed for planetary milling. • One cycle of welding and fracture was observed for attritor milling. • Attritor milling experienced a full cycle of welding and fracture in 80% less time than planetary milling. • Yttria was shown to disperse evenly on the particle surface (τ = 6 a.u). NiCrAl and 0.6 wt% yttria powder are milled via two milling methods: Planetary ball milling at a low RPM with ¼” stainless steel spheres & attritor ball milling at a high RPM with ¼” WC spheres. Powders were sieved post-milling using 325 and 635 mesh. Ball Milling Attritor ball milling showed higher surface area at lower milling times compared to planetary ball milling. Welding occurred at τ = 0.5 a.u. followed by fracture at τ = 1.0 a.u. in the attritor. Planetary ball milling experienced cyclic welding and fracture. Planetary ball milling had less variation in surface area compared to attritor ball milling at lower hours. • Additively manufactured MCrAl(Y) powders are being explored for high temperature, corrosion resistant parts with complex geometries • The MCrAl powders are currently used in thermal spray for their high temperature and corrosion properties. Adding yttria to NiCrAl powders strengthens the alloy by the forced bowing of dislocations through Orowan strengthening. • Ball milling refines particle size and incorporates the yttria into the powders through a cycle of welding particles together and fracturing these agglomerates. Controlling milling parameters like speed, loading and time allows for particle size control. Two milling types were used: • Planetary Milling – powders and media are put in containers which are rotated around a central point. • Attritor Milling – powders and media are put in one container which rotates in place. • Selective Laser Melting (SLM) melts powder spread on a lowering stage according to a computer file layer by layer to create parts with complex shapes. 0 2 4 6 8 10 0.02 0.04 0.06 0.08 0.10 Planetary Specific Surface Area (m^2 / g) Milling Time (a.u.) 0.0 0.2 0.4 0.6 0.8 1.0 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 Attritor Specific Surface Area (m^2 / g) Milling Time (a.u.) Specific Surface Area Scanning Electron Microscopy Starting Materials: Yttria Powder (<10 µm) and NiCrAl Powder (5-50 µm) Increasing Planetary Milling Time Increasing Attritor Milling Time Cycles of welding and fracture occur as milling time is increased from τ = 0 to 10 a.u. Welding and fracture occur faster for attritor milling compared to orbital milling Energy Dispersive X-ray Spectroscopy Element Atomic % Ni 55 Cr 17 O 17 Al 10 Y 1 Elemental analysis shows that yttria is being fractured and dispersed on the NiCrAl particle surfaces. (τ = 6 a.u.) Characterization and Preparation Sites NASA Glenn Purdue University Powder milling BET Surface Area Separation from media SEM Initial sieving Morphologi analysis Morphologi gathering Sieving BET Procedure: • Degassed 12 hours, 250˚C Morphologi Procedure: • Sample dispersed over slide • Automated optical microscope images powders • Diameter, circularity, intensity, etc. gathered Morphologi Particle Size Distributions 0 0.5 4 5 6 8 10 0 20 40 60 80 % Yield Planetary Milling Time (a.u) +325 -325,+625 -625 0.1 0.5 1 0 10 20 30 40 50 60 70 80 % Yield Orbital Milling Time (a.u) +325 -325,+625 -625
Transcript of Development of High Temperature ODS Alloys for Additive ... · lower milling times compared to...
Development of High Temperature ODS Alloys for Additive Manufacturing of Aerospace Structural ComponentsAaron Beckley, Michael Bodziak, Cole Davis, Philip Gordon, Monica ViersFaculty Advisors: Dr. Eric P. KvamIndustrial Sponsors: Dr. David Ellis, Laura Evans
Project Background
Powder processing parameters were explored to incorporate yttria particles into NiCrAl powderfor use as an oxide dispersion-strengthened (ODS) alloy in additive manufacturing. Orbital andattritor milling were used. Particle size analysis, SEM, and specific surface area measurementsshowed that many cycles of particle welding followed by fracture occurred during orbital milling.Compared to orbital milling, attritor milling resulted in faster welding and fracture cycles. EDSrevealed that yttria powder was evenly dispersed onto NiCrAl particle surfaces during milling.
Experimental Procedure
Results & Discussion
Future work
Results & Discussion (cont.)
MSE 430-440: Materials Processing and Design
This work is sponsored by NASA Glenn Research Center in Cleveland, OH.
• Analysis of milling time for the planetary ball mill should be explored, to fill in intermediate times.
• Examination of an increased milling speed to further reduce time while maintaining similar trends.
• Investigate potential oxidation in milling via X-Ray Diffraction.
• Cross-sectional examination to determine yttriadispersion in the core of the particles.
• Cycling through large and small average diameter in both methods
• Two sizes of particles form with attrition milling• Attrition milling takes place over 1/10 the time
AcknowledgementsThank you to Dr. Eric P. Kvam, Dr. David Ellis, Laura Evans, Dr. Quynhgiao Nguyen, Henry DeGroh, and David Scannapieco for their guidance and assistance with this project.
Conclusions• Multiple cycles of welding and fracture were
observed for planetary milling.• One cycle of welding and fracture was observed for
attritor milling.• Attritor milling experienced a full cycle of welding
and fracture in 80% less time than planetary milling.
• Yttria was shown to disperse evenly on the particle surface (τ = 6 a.u).
NiCrAl and 0.6 wt% yttria powder are milled via twomilling methods: Planetary ball milling at a low RPMwith ¼” stainless steel spheres & attritor ball millingat a high RPM with ¼” WC spheres. Powders weresieved post-milling using 325 and 635 mesh.
Ball Milling
Attritor ball milling showed higher surface area at lower milling times compared to planetary ball milling. Welding occurred at τ = 0.5 a.u. followed by fracture at τ = 1.0 a.u. in the attritor. Planetary ball milling experienced cyclic welding and fracture. Planetary ball milling had less variation in surface area compared to attritor ball milling at lower hours.
• Additively manufactured MCrAl(Y) powders are being explored for high temperature, corrosion resistant parts with complex geometries
• The MCrAl powders are currently used in thermal spray for their high temperature and corrosion properties. Adding yttria to NiCrAl powders strengthens the alloy by the forced bowing of dislocations through Orowan strengthening.
• Ball milling refines particle size and incorporates the yttria into the powders through a cycle of welding particles together and fracturing these agglomerates. Controlling milling parameters like speed, loading and time allows for particle size control. Two milling types were used:
• Planetary Milling – powders and media are put in containers which are rotated around a central point.
• Attritor Milling – powders and media are put in one container which rotates in place.
• Selective Laser Melting (SLM) melts powder spread on a lowering stage according to a computer file layer by layer to create parts with complex shapes.
0 2 4 6 8 10
0.02
0.04
0.06
0.08
0.10 Planetary
Spe
cific
Sur
face
Are
a (m
^2 /
g)
Milling Time (a.u.)0.0 0.2 0.4 0.6 0.8 1.0
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45 Attritor
Spe
cific
Sur
face
Are
a (m
^2 /
g)
Milling Time (a.u.)
Specific Surface Area
Scanning Electron MicroscopyStarting Materials: Yttria Powder (<10 µm) and NiCrAl
Powder (5-50 µm)
Increasing Planetary Milling Time
Increasing Attritor Milling Time
Cycles of welding and fracture occur as milling time is increased from τ = 0 to 10 a.u.
Welding and fracture occur faster for attritor milling compared to orbital milling
Energy Dispersive X-ray SpectroscopyElement Atomic
%Ni 55Cr 17O 17Al 10Y 1
Elemental analysis shows that yttria is
being fractured and dispersed on the NiCrAl particle
surfaces.(τ = 6 a.u.)
Characterization and Preparation Sites
NASA Glenn Purdue UniversityPowder milling BET Surface AreaSeparation from media SEMInitial sieving Morphologi analysisMorphologi gathering
Sieving
BET Procedure:• Degassed 12 hours, 250˚C
Morphologi Procedure: • Sample dispersed over slide• Automated optical microscope images powders• Diameter, circularity, intensity, etc. gathered
Morphologi Particle Size Distributions
0 0.5 4 5 6 8 100
20
40
60
80%
Yie
ld
Planetary Milling Time (a.u)
+325 -325,+625 -625
0.1 0.5 10
10
20
30
40
50
60
70
80
% Y
ield
Orbital Milling Time (a.u)
+325 -325,+625 -625
