|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Non-equilibrium Features of Grain Boundaries
||Topological Defects in 2D Orientation-field Models for Grain Growth
||Bálint Korbuly, Mathis Plapp, Hervé Henry, James A. Warren, László Gránásy, Tamás Pusztai
|On-Site Speaker (Planned)
Standard two-dimensional orientation-field based phase-field models rely on a continuous scalar field to represent crystallographic orientation. The corresponding order parameter space is the unit circle, which is not simply-connected. This topological property has important consequences for the resulting multi-grain structures: (i) trijunctions may be singular; (ii) for each pair of grains, there exist two different grain boundary solutions that cannot continuously transform to one another; (iii) if both solutions appear along a grain boundary, a topologically stable, singular point defect must exist between them. While (i) can, (ii) and therefore (iii) cannot be interpreted in the classical picture of grain boundaries. In addition, singularities cause difficulties, such as lattice pinning in numerical simulations. To overcome these problems, we propose two new formulations of the model. In both cases, the additional degree of freedom introduced make the order parameter space simply-connected, which removes the topological stability of these defects.
||Planned: Supplemental Proceedings volume