Fast parallel algorithms for short-range molecular dynamics
Journal of Computational Physics
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The self-diffusion properties of several βSn symmetric tilt grain boundaries are examined using molecular dynamics simulations. The boundary types examined---(101), (201), (401), (310)-Σ5, and (410)---are chosen from those observed in experiment and from arbitrary Miller planes, giving a variety of tilt angles and interface properties. Planar structure factor and diffusivity profiles for each boundary are computed and a grain boundary width, δGB, is measured from these profiles. Larger diffusive widths (δGB) are exhibited by higher excess potential energy grain boundaries. Diffusivities (DGB) in the directions parallel to the interface plane are computed and activation energies are found with the Arrhenius relation. DGB (as δGBDGB normalized by δGB) is shown to agree well with experiment. We also investigate the anisotropic diffusive behavior of the (401) grain boundary and find that the low energy grain boundary exhibits very low activation energy diffusion, due to the development of diffusive channels.