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Mar 20 2024

Elucidating the Role of Microstructural Defects on the Plasticity of Metals and Alloys using Mesoscale Models

CME Department Seminar

March 20, 2024

11:00 AM - 12:00 PM America/Chicago


ERF 1047 and Zoom at


842 W. Taylor St., Chicago, IL 60607

Presenter: Darshan Bamney, PhD, Los Alamos National Laboratory
Location: ERF 1047 and Zoom at

Abstract: Plasticity in polycrystalline metals and alloys (e.g., Mg, Ti and their alloys) is mediated by the concomitant activation, propagation, and interactions of microstructural defects, such as dislocations, grain boundaries (GBs), and deformation twins. In essence, the nucleation, propagation, and interactions of these defects accommodates strain during plastic deformation in these materials. Within the hierarchy of multiscale simulation techniques used to model defect behaviors/mechanics, mesoscale methods, such as discrete dislocation dynamics (DDD) and the phase-field (PF) method have emerged as powerful techniques to simulate microstructure evolution. These mesoscale methods enable bridging between the atomistic-scale behaviors of defects and continuum-level descriptions of plasticity, allowing us to unravel the microstructural basis of plasticity (qualitatively and quantitatively) in technologically important metals/alloys, with implications for optimizing their performance in various engineering applications.

The focus of this seminar will be on our recent efforts in developing and utilizing highfidelity mesoscale techniques (DDD, PF, and PF-crystal plasticity) to advance our understanding of microstructure-property relationships in metallic materials. As a specific example, our recent efforts in investigating the interactions between deformation twins and precipitates in lightweight alloys will be discussed. First, the development of an atomistically-informed anisotropic phasefield model for deformation twinning will be presented. Then, the application of the model to systematically investigate the precipitation strengthening effect in Mg-alloys will be described. Specifically, the interactions between twins and precipitates are studied, considering the influence of precipitate size, geometry, coherency, and density on the strengthening effect. Following this, an analytical strengthening model is developed that can quantitatively extrapolate these effects to experimentally-relevant scenarios with good accuracy. This work enables the community at large to predict precipitation strengthening effects (against twinning) in lightweight alloys. Finally, future research plans, which entail leveraging these mesoscale simulation techniques, will be discussed.

Speaker Bio: Dr. Darshan Bamney is a postdoctoral research associate in the Materials Science and Technology Division at Los Alamos National Laboratory. He is presently working on investigating the deformation behavior of lightweight alloys in complex thermo-chemo-mechanical environments using high-fidelity mesoscale methods (dislocation dynamics, phase-field, and crystal plasticity models). He received his M.S. and Ph.D. in materials science and engineering from the University of Florida in 2017 and 2021, respectively. His research focuses on the development and use of advanced multi-scale simulation methods to: (i) explore various physical phenomena critical to the thermo-chemo-mechanical properties of materials, and (ii) enable bridging between experimental and modeling efforts.


Prof. Matthew Daly

Date posted

Mar 18, 2024

Date updated

Mar 18, 2024