|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Non-equilibrium Features of Grain Boundaries
||Reconciling Grain Growth and Shear-coupled GB Migration
||Spencer Louis Thomas, Kongtao Chen, Jian Han, Prashant K Purohit, David J. Srolovitz
|On-Site Speaker (Planned)
||Spencer Louis Thomas
While the conventional curvature flow model of grain boundary (GB) migration has greatly contributed to our understanding of grain growth, it fails to account for phenomena observed in both experiment and MD simulations. Such deviations include
grain rotation, stress generation, defect formation, and GB stagnation.
We know that GB motion is mediated by disconnections (line-defects characterized by Burgers vectors and GB steps) and, consequently, that migration is coupled to shear stress. Such shear-coupled migration is well-documented. However, the ramifications of shear-coupling amid the mechanical constraints present in a microstructure remain a mystery.
We present a series of molecular dynamics simulations of GB migration in polycrystals and bicrystals that show how microstructure constraints affect GB migration, then construct a quantitative model based on disconnection nucleation that illustrates the mechanistic flexibility that permits long-range GB migration during polycrystalline grain growth.
||Planned: Supplemental Proceedings volume