Phase field crystal modeling of grain rotation with small initial misorientations in nanocrystalline materials

The process of grain rotation with small initial misorientation angles in nanocrystalline materials is investigated by using the phase field crystal (PFC) method. Simulation results reproduce the grain rotation process of nanocrystalline grains and are consistent with the classical coupled motion theory excellently. The grain rotation with very small initial misorientations, which cannot be illustrated via the Frank formula because of the large elastic distortion in the grain, is reasonably described by the strain field analysis. It is also revealed that the significant elastic distortion induced by grain boundaries (GBs) determines the rotational dynamics; moreover, the movement of grain boundary dislocations (GBDs) plays a dominant role in the evolution of elastic distortions which results in the grain rotation.