We generalize a previous study of the atomic motions governing grain boundary migration to consider arbitrary misorientations of  tilt boundaries. Our examination of the nature of atomic motions employed three statistical measures: the non-Gaussian parameter, the 'dynamic entropy', and the van Hove correlation function. These metrics were previously shown to provide a useful characterization of atomic motions both in glass-forming liquids and strained polycrystalline materials. As before, we find highly cooperative, string-like motion of atoms, but the grain boundary migration itself is a longer time scale process in which atoms move across the grain boundary. These observations are consistent with our previous results for Sigma 5  tilt boundaries. It is evident from our work that the grain boundary structure and misorientation have a significant influence on the rate of grain boundary migration.
Citation: Acta Materialia
Pub Type: Journals
grain boundaries, migration, simulation