Phase field crystal simulations of nanocrystalline grain growth in two dimensions

We study two-dimensional grain growth at the nanoscale using the phase field crystal (PFC) model. Our results show that for circular grains with large misorientations the grain area decreases linearly with time, in good agreement with classical grain growth theory. For circular grains with small initial misorientations, grain rotation occurs as a result of the coupled motion between the normal motion of the grain boundary and the tangential motion of the adjacent grains. Despite this rotation and its effect on the grain boundary energy, the grain area decreases linearly with time. In addition, for intermediate initial grain misorientations, we find a repeating faceting–defaceting transition during grain shrinkage and a different relationship between the grain area and time, which suggests a different grain growth mechanism than that for small and large misorientations. For a circular grain embedded between a bicrystal with a symmetric tilt boundary, we find that the evolution of the embedded grain closely depends on dislocation reactions at triple junctions.