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Polycrystalline crystal plasticity with grain boundary evolution
March 8, 2017 @ 11:45 am - 1:00 pmFree
Speaker: Nikhil Chandra Admal, Ph.D.,
Department of Materials Science and Engineering,
University of California, Los Angeles
Time: 11:45 a.m. to 1 p.m. (Lunch will be served*)
Date: March 8, 2017
Location: 5628, Math Sciences Building
Abstract: Dynamic recrystallization can be defined as a spontaneous change in the mi- crostructure of a material during deformation at an elevated temperature due to the growth of defect-free grains through the motion of high angle grain boundaries. One of the most important uses of recrystallization is in metal processing, where recrystallized grains increase the ductility, resulting in better control of the grain structure. On the other hand, it is undesirable from a design perspective, since recrystallization alters the microstructure resulting in a change in the material’s macroscopic properties. In this talk, I will describe our ongoing work on modeling grain growth during recrystallization in the presence of external loads.
Dynamic recrystallization is a uniquely challenging phenomenon to model since the microstructure and the material deformation evolve at the same time scale. Grain boundary motion in the absence of deformation is commonly modeled using phase field models, while the deformation of a material with a fixed grain boundary structure is commonly modeled using crystal plasticity. In this work, we develop a thermodynamically consistent model which models deformation and grain growth simultaneously, thus enabling us to understand dynamic recrystalliza- tion. The highlight of this model is it is a non-classical gradient elastic model that can simulate various interesting phenomena observed in dynamic recrystallization, where a grain rotates to increase/decrease its misorientation as its grain boundary evolves.
About Speaker: Dr. Nikhil Chandra Admal is postdoctoral research scholar working with Prof. Jaime Marian in the Materials Science and Engineering department at UCLA. He is broadly interested in the multiscale modeling of materials at various length and times scales ranging from the atomic scale to the continuum scale. Currently, the focus of his research is on the study of recrystallization in refractory materials to increase their operating temperature, and development of first-principles strain gradient elastic models to include non-local effects relevant in micromechanical systems, and systems with defects.
Prior to joining UCLA, Dr. Admal obtained his PhD from the Department of Aerospace Engineering and Mechanics at the University of Minnesota.
*Lunch will be served at 11:45 AM.
**To ensure you have a space at the seminar, please RSVP by March 05, 2017.