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Seminar: Multi-scale modeling and characterization of single-, multi- and polycrystalline BCC metals

Hojun Lim, Sandia National Laboratories
Thursday, May 2, 2019, 9:30 am to 10:30 am
210E Baker Systems
1971 Neil Avenue
Columbus, OH 43210

Seminar by Hojun Lim

Department of Computational Materials and Data Science

Sandia National Laboratories

 

Understanding the fundamental plastic behavior of polycrystalline metals using computational models requires physically-based, multi-scale materials models and quantitative validation with experiments. In addition, accurate representations of microstructures are critical in investigating process-structure-property (PSP) linkages and materials variability in performance. In this work, a meso-scale micromechanical model informed from atomistic simulations is used to predict plastic deformations of single-, multi- and poly-crystalline metals. Crystal plasticity-finite element (CP-FE) model is parameterized from molecular dynamics (MD) simulations and single crystal experiments, and used to investigate the effects of microstructural variability in local and global stress-strain responses. Heterogeneous deformations of BCC metals are quantitatively compared with various experiments. In addition, the results are used to parameterize continuum models of BCC metals and predict dynamic behaviors under extreme conditions. This framework provides an efficient and direct link from the fundamental dislocation physics to the continuum-scale plastic deformation of polycrystalline metals.

Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

Hojun Lim is a senior member of technical staff at Computational Materials and Data Science group at Sandia National Laboratories. He received his B.S. from Seoul National University in South Korea in 2005 and M. S./ Ph. D. from The Ohio State University in 2010 majoring Materials Science and Engineering. Before joining Sandia in 2012, he spent 2 years in Rob Wagoner’s group at OSU as a post-doctoral appointee. His research focuses on multi-scale computational materials modeling with an emphasis on mechanical properties of metallic materials. He is involved in several research projects related to topics on multi-scale modeling, crystal plasticity, finite element method, high rate deformations and materials data science.