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Michael J. DemkowiczDepartment of Materials Science and Engineering, Texas A&M University,
College Station TX, 77843
SSAP symposiumFeb. 26-27, 2020Washington, DC
This work was supported by the Department of Energy, National Nuclear Security Administration, under Award no. DE-NA0003857
• Lead: Texas A&M University, director: M. J. Demkowicz (MSEN)• Collaborating institutions: UCSB, U. Michigan, U. Connecticut• Goals:
• Discover, understand, and predict the influence of microstructural heterogeneities—such as interfaces, inclusions, and porosity—on the high strain rate (>104/s) mechanical response of multiphase metallic materials (M3)
• Apply this fundamental understanding to certification of high-performance additively manufactured M3
• Train the next generation of leaders in stockpile stewardship through close collaboration with partners at NNSA labs
Passionate faculty
Developing new capabilities
Training stewardship science leaders
NNSA/SSAA center of excellence, Est. July 2018
Who we are (see credds.tamu.edu for more details)Four institutions:
PI: M. J. Demkowicz Co-PI: I. J. Beyerlein Co-PI: A. Misra Co-PI: A. Dongare
28 team members:
7 external advisors:
• 10 faculty • 17 PhD students • 4 postdocs • 1 tech • 1 admin officer
Ellen Cerreta (LANL), Mukul Kumar (LLNL), Brad Boyce (SNL), Don Brenner (NCSU), Marisol Koslowski (Purdue), Lori Graham-Brady (JHU), Pradeep Guduru (Brown)
Faculty profilePrior employment
at NNSA labs (LANL)
NAE members Early career
Demkowicz
Misra
Beyerlein
NRC fellow at US-ARO
PollockPharr
NeedlemanMazumder
Selected honors at LANL:• LANL Fellow (Misra)• Oppenheimer fellow (Beyerlein)• Director’s fellow (Demkowicz)• EFRC directors (Misra, Beyerlein)
• Mazumder: direct metal deposition• Needleman: fracture modeling• Pharr: nanoindentation• Pollock: advanced metallic materials
Dongare
Senior facultyHartwig Zok
High strain rate testing
SPD processing
Student profile
• 17 PhD students currently supported by CREDDS, all US persons:
• 6 at TAMU, 4 at UM, 5 at UCSB, 2 at UConn
• 1st year (2):• UCSB: Lauren Poole, Wyatt Witzen
• 2nd year (7):• TAMU: Liya Semenchenko, Emmeline Sheu,
Ta Duong, Chris Walker• UM: Daniel Yin• UCSB: Toby Francis• UConn: Marco Echeverria, Jessica Maita
• 3rd year (2):• TAMU: Wesley Higgins, Edwin
Chiu• 4th year (4):
• UM: Ethan Sprague, Max Powers• UCSB: Avery Samuel, Paul
Christodoulou• 5th year (1):
• UM: Ben Derby
Multiphase metallic materials (M3)
Cu-Nb composite made by severe plastic deformation
Cu-W composite made by liquid metal dealloying
Additively manufactured Ni-base alloy Inconel 718
Microstructure is the key difference between M3 and single crystal solids
Levels of microstructure
Defect
Composite
Mesoscale
Phase Interface
Twins, precipitates, impurities, porosity
Misfit dislocations, disconnections, facets
Texture, grain shape Crystallographic character, complexions
Phase fraction, composite morphology
Interface connectivity
Levels of microstructure
Defect
Composite
Mesoscale
Phase Interface
Twins, precipitates, impurities, porosity
Cu/Ta multilayer under shock loading
Levels of microstructure
Defect
Composite
Mesoscale
Phase Interface
Misfit dislocations, disconnections, facets
General GB in Cu
Levels of microstructure
Defect
Composite
Mesoscale
Phase Interface
Texture, grain shape
Polycrystalline Ta
Levels of microstructure
Defect
Composite
Mesoscale
Phase Interface
Crystallographic character, complexions
GB character effect on intergranular fracture
Levels of microstructure
Defect
Composite
Mesoscale
Phase Interface
Phase fraction, composite morphology
DMD-CuFe
Levels of microstructure
Defect
Composite
Mesoscale
Phase Interface
Interface connectivityMixed strong/weak grain boundaries in a polycrystal
Levels of microstructure
Defect
Composite
Mesoscale
Phase Interface
Twins, precipitates, impurities, porosity
Misfit dislocations, disconnections, facets
Texture, grain shape Crystallographic character, complexions
Phase fraction, composite morphology
Interface connectivity
High strain rate response of M3
HAGB
J. P. Escobedo et al., J. Appl. Phys. 110, 033513 (2011)
Spall plane
Spall failure in polycrystalline Cu
R. F. Zhang et al., Scripta Mater. 68, 114 (2013)
Interfacial plasticity in Cu/Nb multilayers
TwinningNo twinning
PVD interfaces
ARB interfaces
An integrated research strategyAdvanced processing Pre-test characterization
High strain-rate testing Post-test characterization
Physics-based modeling
UM, TAMU, LANL TAMU, UCSB, UM
UCSB, UConn, TAMU, LANL, LLNL
TAMU, UCSB, LANL, LLNL UM, UCSB
Data-driven inference and optimization
UCSB, TAMU
Simultaneous testing and simulation of equivalent
microstructures
Optimization of successive experiments and microstructures to address science hypotheses
Data-based integration of experimental and
modeling results
New capability:Performance certification for AM M3
New capabilities:• High strain rate nanoindentation• High speed in situ DIC
Our work follows an iterative
”design-synthesize-test” (DST) model
Thrust 1: effect of interface microstructure on flow localization in high strength M3 under dynamic loading
The key to certification of additive and advanced manufactured M3 is linkinginterfacial microstructure with unit mechanisms of flow localization
Predictive models
Advanced Manufacturingof Novel M3
PVD DMD SPD
Interface Microstructure: Spacing Shape Crystallography, texture Defect structureChemistry
Certification Metrics- Strength level- Uniform vs localized
plastic flow
SHPB, Gas gun performance test
atomistic mesoscaleMulti-scale modeling
unit mechanisms:Twin and/or Slip Shear band formation
High-throughput Dynamic Behavior: Interface unit mechanisms
HRTEM: Twin and/or SlipHigh rate nanoindenter
Flow Localization Behavior:Interface effects measured in situ
in situ SEM nanomechanics in situ DCS
Shear band
Thrust 2: effect of interface microstructure on spall response of high strength M3 under dynamic loading
The key to certification of additive and advanced manufactured M3 is relating interfacial microstructure with void evolution
Advanced Manufacturingof Novel M3
PVD DMD SPD
Interface Microstructure: Spacing CrystallographyDefect structureChemistryPhase Shape and texture
Certification Metrics- Spall strength- Delocalized
void evolution
Flyer plate performance test
atomistic
Microstructure-sensitive modeling
Nucleation Heterogeneous stress states
High rate mechanical response: Mechanics and microstructure of void evolution
SHPB
DIC
Gas Gun
Incipient voids; coalesced voids
HRTEM.TEM/SEM
Data analysis and modeling
mesoscale
3D TriBeam Void at 4P
Microstructural CharacterizationInterface directed void evolution
Micro-CT
Example: flow localization in laminatesProcessing of Cu/Ta M3 by
accumulated roll bonding (ARB)
CREDDS goals:• Process layered
composites for plate impact testing
• Contrast Cu/Ta with Cu/Nb: comparable chemistry, but large density contrast
Engagement with LANL:• Spring 2019 working
at Sigma Division with D. Coughlin
• Optimize processing• Characterize products
Hydrocode modeling at SNL (ongoing)
Edwin Chiu(TAMU)
Avery Samuel (UCSB)
Flier plate impact testing (LANL, summer 2020)
LiyaSemenchenko
(TAMU)
Atomistic simulations (Dongare, Echeverria)Post-test characterization (Misra, Derby)
In situ testing at the Dynamic Compression Sector (Dongare, Misra, Kumar)
Example: ”weakest links” for spall failureDevelopment of 3-D FFT CP
mesoscale models
CREDDS goals:• Simulate site-specific
damage initiation in M3 under spall
• Apply to performance certification of AM M3
Engagement with LANL:• Spring 2019 working
at T-Division with Ricardo Lebensohn
• Improve models• Validate against
experiments
3-D reconstruction using TriBeam
Toby Francis (UCSB)
Compare to spalled samples from LANL
Multiphase M3 (Hartwig, Levin, Mazumder, Sprague)
Microstructure analysis (Demkowicz, Pollock)
Coil/magnet assembly
Leaf springs
Capacitance gauge
Indenter / Tip
Sample
Load Frame
New capabilities: >104/s nanoindentation
• High speed micromechanical testing• Nanoindentation• Micropillar compression
• High speed imaging• In situ digital image correlation (DIC)• High speed ultraviolet microscopy
George Pharr(TAMU)
Phani and Oliver, Materials 10, 663 (2017)
New capabilities: rapid screening of materials for dynamic response
High strain rate deformation during high speed cutting
Images courtesy of Dinakar Sagapuram (TAMU)
Continuum modeling of cutting
Umair Bin Asim(TAMU)
Bayesian inference of mechanical response by matching models to experiments
Students in residence at NNSA labs
• Five CREDDS students with ~semester-long stints at NNSA labs in FY1:
• Our goal is to send all of our PhD students for at least one such internship at a NNSA lab in the course of their PhD
• We are seeking to expand internship opportunities at SNL and LLNL
Paul Christodoulou Ben Derby Liya Semenchenko Avery Samuel
LANL, Ricardo Lebensohn (MST-8)
LANL, Kevin Baldwin (CINT)
LANL, Dan Coughlin (Sigma)
LANL, SaryuFensin (MST-8)
(UCSB) (Michigan) (TAMU) (UCSB)Marco Echeverria
LLNL, TomorrHaxhimali, Robert
Rudd (MSD)
(Connecticut)
Students in residence at NNSA labs
• Five CREDDS students with ~semester-long stints at NNSA labs in FY2:
• Our goal is to send all of our PhD students for at least one such internship at a NNSA lab in the course of their PhD
• We are seeking to expand internship opportunities at SNL and LLNL
Paul Christodoulou Edwin Chiu Liya Semenchenko Emmeline Sheu
LANL, Ricardo Lebensohn (MST-8)
SNL, John Mitchell (CCR)
LANL, SaryuFensin (MST-8)
LANL, Darrick Williams (CINT)
(UCSB) (TAMU) (TAMU)Ethan Sprague
LLNL, Ibo Matthews (NIF)
(Michigan)(TAMU)
CREDDS alumni transitioning to NNSA labs
We are seeking to create a pipeline to SNL and LLNL, as well
Ben Derby
Postdoc, LANL MST-8 (starts May 2020)
(Michigan PhD)Zachary Levin
TSM, LANL MST-16 (started Jan. 2020)
(TAMU postdoc)
Technical collaborations with NNSA labs
564K cycles 644K cycles 724K cycles
Collaboration between TAMU and CINT/SNL on crack healing during fatigue loading
Hydrostatic stress due to CTB migrationCollaborating with Boyce, Barr, Hattar,
Bufford (SNL)
Ta Duong(TAMU)
Crack healing in metals is an example of how microstructure modifies mechanical response
Outreach to undergraduates
CREDDS supported 12 undergraduate researchersSummer USRG students at TAMU Rowan Baird won 1st place in
the TAMU REU/USRG poster competition
Engagement between two NNSA centers at TAMU: CREDDS and CENTAUR
This effort builds a graduate recruiting pipeline for all SSAP programs
Organization of technical meetings• CREDDS PhD student, Max Powers (Michigan), co-
organized a student-run symposium at TMS 2019: “Science Policy Within the Materials Research Community”
• Demkowicz was on the program committee of LANL-sponsored workshop “Adaptive Sample Preparation and Target Fabrication for High-Throughput Materials Science”
• Dongare and Beyerlein co-organized fall 2019 MRS symposium “Extreme Mechanics”
• Dongare is co-organizing a TMS 2020 symposium on “Understanding and Predicting Dynamic Behavior of Materials”
• In 2021-2022 (FY4), CREDDS will hold a week-long summer school on materials research topics in stockpile stewardship
Poster presenters at 2020 SSAP symposiumEdwin Chiu
(TAMU)Umair Bin Asim
(TAMU)Max Powers(Michigan)
Lauren Pooler(UCSB)
Daniel Yin(Michigan)
Frank Zok(UCSB)
Ethan Sprague(Michigan)
Emmeline Sheu(TAMU)
Ted Hartwig(TAMU)
Ta Duong(TAMU)