Integration between Modeling and Experiments for Crystalline Metals: From Atomistic to Macroscopic Scales IV: Session I
Sponsored by: TMS Advanced Characterization, Testing, and Simulation Committee, TMS Materials Characterization Committee, TMS: Nanomaterials Committee
Program Organizers: Arul Kumar Mariyappan, Los Alamos National Laboratory; Irene Beyerlein, University of California, Santa Barbara; Levente Balogh, Queen's University; Caizhi Zhou, University of South Carolina; Lei Cao, University of Nevada; Josh Kacher, Georgia Institute of Technology
Monday 8:00 AM
October 10, 2022
Room: 401
Location: David L. Lawrence Convention Center
Session Chair: Amit Misra, University of Michigan; Hamidreza Abdolvand, The University of Western Ontario
8:00 AM Invited
Integration of Experiments and Modeling in Polycrystalline Plasticity of Mg-Al Single Phase Alloys: Moshen Andani1; A Lakshmanan1; Y Yoo1; V Sundararaghavan1; J Allison1; Amit Misra1; 1University of Michigan
In dilute Mg-Al single phase alloys, high-resolution electron backscatter diffraction is used to measure barrier strength of specific grain boundaries to basal and prismatic slip systems. Site-specific transmission electron microscopy is used to elucidate the dislocation mechanisms at grain boundaries. The results are analyzed using dislocation pile-up model and used to calibrate grain size strengthening parameters in a crystal plasticity model. Integration of local experimental measurements of dislocation-interface interactions with computational modeling at corresponding length scales is shown to be effective in developing predictive crystal plasticity finite elements models of stress strain response for different textures and grain sizes.
8:30 AM Cancelled
Modeling of the Tension-compression Asymmetry Reduction of ECAPed Mg-3Al-1Zn Through Grain Fragmentation: Georges Ayoub1; Ali Kobaissy2; Mutasem Shehadeh2; 1University of Michigan; 2American University of Beirut
A physically based model accounting for grain-to-grain interaction and grain refinement mechanisms is proposed to predict the anisotropic mechanical response and the texture evolution in ECAPed Mg-3Al-1Zn. The proposed model couples two approaches: crystal plasticity (CP), including twinning, and continuum dislocation dynamics (CDD). A grain refinement mechanism is also integrated into the model in order to predict the formation of refined grains during severe plastic deformation. A robust parameter identification method is proposed, in which experimentally reported process parameters are calibrated to fit the simulated mechanical behavior, texture evolution, and deformation systems-related activities. The anisotropic behavior evolution of the Mg-3Al-1Zn hot-rolled plate is examined by predicting the mechanical behavior, dislocation evolution, and slip/twin systems activities of the ECAPed material. The coupled CP-CDD model predicted grain size reduction, textures and the mechanical behavior post ECAP in routes 4A and 4K which are in agreement with the experimentally measured values.
8:50 AM
Concurrent Atomistic-continuum Simulation of the Interplay between Dislocations, Phase Transformation, Twinning, and Reverse Phase Transformation in Plastically Deformed Materials: Liming Xiong1; 1Iowa State University
Taking a two-phase material subjected to a plastic deformation as a model system, here we present results from a series of computational analysis on how a dislocations pileup is formed at the interface and how it contributes to the subsequent twinning and phase transformations (PTs), through concurrent atomistic-continuum simulations. One main novelty of this work is a simultaneous resolution of the μm-level dislocation slip, the internal stress complexity, the atomic-level interface structure relaxation, twinning/PT nucleation and growth near the slip-interface intersection all in one model. The dislocation pileup-induced local stress concentration is found to dictate the subsequent structure evolution: (a) a simultaneous occurrence of twinning and PTs; and (c) a 60% reduction of the PT pressure when tens of dislocations are piled up at the buried interface. The gained knowledge may find applications in understanding the dislocation slip, twinning, PTs and their interaction in many advanced alloys under mechanical loadings.
9:10 AM
Mapping the Dislocation Density Around a SS316L Weld Using Synchrotron X-ray Diffraction to Validate Finite Element Method Plasticity Modeling: Lucas Ravkov1; Ondrej Muransky2; Levente Balogh1; 1Queen's University; 2Australian Nuclear Science and Technology Organisation
High-energy synchrotron X-ray diffraction measurements were conducted in a grid pattern on the cross section of a three-pass weld specimen, consisting of 515 measurement locations in a 30 mm x 18 mm area, with over 12000 individual diffraction patterns obtained. A software was developed to extract the Full Width at Half Maximum (FWHM) and the position of every reflection in each of the ~12000 patterns using non-linear least squares fitting. Analysis of the peak broadening (FWHM) versus grid position reveals that the highest level of plastic strain is found in the Heat Affected Zone (HAZ) of the weld. Full-pattern Diffraction Line Profile Analysis (DLPA) combined with modified Williamson-Hall analysis is performed to quantitatively determine the dislocation density versus location around the weld. The obtained DLPA results are then compared to EBSD measurements, and Finite Element (FE) predictions of the same region to validate the applied plasticity models.
9:30 AM Invited
New Insights into the Spatiotemporal Structure of Plastic Flow In hcp Materials by Combination of Advanced In Situ Techniques and Modeling: Kristian Mathis1; 1Nuclear Physics Institute of the CAS
A rare blend of advanced in situ techniques including neutron diffraction, acoustic emission measurements, in situ SEM, and high-speed microscopic video imaging is used to study the deformation mechanisms in Mg and Zn alloys. The different spatiotemporal resolutions of these techniques, ranging from microscale to macroscale, enable verification of theoretical calculations performed by elastoplastic self-consistent modeling, molecular dynamic simulations, and discrete dislocation dynamics. It is shown that such a unique combination of experiments and computer simulations results in revealing the complex spatiotemporal structure and otherwise inaccessible fine microstructural details of the plastic flow in hcp structured materials.
10:00 AM Break
10:20 AM
Role of Dislocations and Deformation Twinning on the High-pressure Phase Transformation in Zirconium: Arul Kumar Mariyappan1; T Yu2; Y Wang2; Rodney McCabe1; Carlos Tome1; Laurent Capolungo1; 1Los Alamos National Laboratory; 2The University of Chicago
Using X-ray synchrotron and neutron diffraction techniques, the role of slip dislocations and deformation twins on the α-to-ω phase transformation (PT) in high purity zirconium is investigated. In-situ X-ray synchrotron-based quasi-hydrostatic pressure experiments are performed on pre-strained Zr-samples to capture the effects of pre-existing slip dislocations and twins on PT. These high-pressure experiments reveal that pre-existing prismatic <a> dislocations and tensile twins favor the PT compared to pyramidal<c+a> dislocations and compression twins. The pressure required to start and end the α-to-ω PT is lower for existing prismatic<a> dislocations and tensile twined microstructures. The neutron diffraction-based in-situ pressure-hold experiments are performed to understand the PT kinetics. These experiments reveal that the PT rate increases with the holding pressure. Detailed analysis of the experimental data in connection with the Avrami equation finds that the nucleation and migration rates of slip dislocations increase with the imposed pressure and thus accelerate the α-to-ω PT.
10:40 AM
A Numerical Study on How Surfaces Bias Relative Slip Family Activity: Ruxin Zhang1; Thomas Bieler1; Philip Eisenlohr1; 1Michigan State University
Surface observations of dislocation activity have been used in the past to establish relative critical resolved shear stress values. This study demonstrates through crystal plasticity simulations that the reduced constraint at the surface is causing a systematic modulation of relative slip family activity within a boundary layer about one grain deep compared to the bulk behavior. Easily activated (soft) slip families—in particular if those are kinematically incomplete such as hexagonal basal or prism slip—tend to activate relatively more compared to the harder slip families near the surface.
11:00 AM Invited
Deformation Mechanisms of Hexagonal Close-packed Materials: Modeling and Experimentation: Hamidreza Abdolvand1; 1The University of Western Ontario
Slip and twinning are the two main deformation mechanisms observed in hexagonal close-packed (HCP) polycrystals such as zirconium and magnesium alloys. This presentation will focus on characterizing the micromechanics of slip and twining using crystal plasticity finite element (CPFE) modeling and diffraction techniques. Three-dimensional synchrotron X-ray diffraction as well as electron backscatter diffraction are used to study formation of slip bands and twins. The “as-measured” microstructures are mapped into a CPFE model for further analysis. The evolution of 3D grain-resolved stresses will be discussed, so as the application of such measurement and modeling approaches in analyzing applied engineering problems.