Phase field modeling of pore electromigration in anisotropic conducting polycrystals

A phase field model is developed to investigate the migration of pores driven by an electric field in polycrystalline materials with anisotropic electrical conductivity. Mass diffusion describing pore migration is coupled with charge conduction by solving microscopic Ohm's law. The model accounts for grain structure dependent conductivity distribution which affects pore migration velocity and path. As an example, the model is applied to simulate pore migration in tin polycrystals. Significant effects of the grain orientation on pore migration is observed which are analyzed in terms of the orientation-dependent conductivity in individual grains and the mismatch of conductivity across grain boundaries. The effects of conductivity anisotropy on the interactions between pores and pore coalescence are also discussed.