Presentation Title: Dynamical Phase Transitions at Grain Boundaries
Prof. David Srolovitz presented this talk in the webinar on Materials Science, Engineering and Technology organized by Vebleo
Authors: David J Srolovitz1*, Kongtao Chen2, Jian Han1
Affiliation:
1City University of Hong Kong, Kowloon, Hong Kong SAR, China
2University of Pennsylvania, Philadelphia, PA 19004, USA
Biography
David Srolovitz is the author of over 500 research papers on materials theory/simulations of defects, microstructure, deformation, and film growth and has an h-index of 100. Prof. David Srolovitz is a Member of the US National Academy of Engineering, Fellow of MRS, TMS, ASM, Institute of Physics and is the winner of the MRS Materials Theory Award.
Prof. David Srolovitz was a staff member at Exxon Corporate Research and Los Alamos National Laboratory and the Executive Director of the Institute for High Performance Computing in Singapore. He has been a professor at the University of Michigan, Princeton University, Yeshiva University and the University of Pennsylvania.
Prof. David Srolovitz has held faculty positions in Materials Science, Mechanical Engineering, Aerospace Engineering, Computer Science, Physics, and Applied Mathematics. He is currently Chair Professor at the City University of Hong Kong, Head of Materials Science and Engineering, and Senior Fellow of the Hong Kong Institute for Advanced Study.
Abstract
The formation and migration of disconnections (line defects constrained to the grain boundary (GB) plane with both dislocation and step character) control many of the kinetic and dynamical properties of GBs and the polycrystalline materials of which they are central constituents. We demonstrate that GBs undergo a finite-temperature topological phase transition of the Kosterlitz-Thouless (KT) type.
This phase transition corresponds to the screening of long-range interactions between (and unbinding of) disconnections. This phase transition leads to abrupt change in the behavior of GB migration, GB sliding, and roughening. We analyze this KT transition through mean field theory, renormalization group theory, and kinetic Monte Carlo simulations, and examine how this transition affects microstructure-scale phenomena such as grain growth stagnation, abnormal grain growth and super plasticity.
This talk was delivered in the webinar organized by Vebleo