Deformation study of bicrystalline and nano-polycrystalline structures using phase field crystal method

Abstract

Deformation behaviors of bicrystalline and nano-polycrystalline structures of various tilt angles and inclination angles in two dimensions are investigated in detail using a two-mode phase field crystal model. The interaction between grain boundary (GB) and dislocation is also examined in bicrystals and nano-polycrystals that both contain asymmetric and symmetric tilt GBs, with energy analysis being carried out to analyze these processes. During deformation simulations, we assume the volume of each simulation cell at every time step is coincident with that of the initial state just before deformation. Our simulation results show that the behaviors of symmetric and asymmetric GBs in bicrystals and nano-polycrystals differ from each other depending on tilt angle and inclination angle. A new dislocation emission mechanism of interest is observed in bicrystals which contain low angle symmetric tilt GBs. Low angle GB has a higher mobility relative to high angle GB in both bicrystalline and nano-polycrystalline structures, as does asymmetric GB to symmetric GB. The generation, motion, pileup and annihilation of dislocations, grain rotation and grain coalescence are observed, which is consistent with the simulation results obtained by molecular dynamics. These simulation results can provide strong guidelines for experimentation.