Influence of grains orientation on the migration velocity of high-angle boundaries

Physical and mechanical properties of polycrystalline materials are determined by the current state of the material structure at various scale levels. The most effective method of forming this structure is thermomechanical processing. The correct physical modeling provides an opportunity to optimize and develop new methods for obtaining materials with the necessary characteristics. The aim of the work is a physically correct mathematical description of the process of dynamic recrystallization. The boundary migration velocity is essentially connected with the driving and retarding forces acting on the boundary. In the process of recrystallization under consideration the driving force is the difference in the energy stored in neighboring grains. Grain boundary energy prevents the normal movement of the high-angle boundary and its bending. A significant anisotropy of the growth rate of high-angle boundaries is observed. This phenomenon is primarily associated with the physical mechanism of migration of grain boundaries. The analysis of the literature shows that the normal motion of high-angle boundaries provides defects in grain boundaries, namely grain boundary steps. The boundary migration velocity is determined by the density of these defects, their height, and velocity of individual defects. The numerical study of the influence of misorientation of neighboring grains and boundaries on the migration velocity is considered. It is shown that for face-centered cubic polycrystals the Kronberg-Wilson relations are satisfied. © 2017 Begell House, Inc.