Diffusive shrinkage of a void within a grian of a stressed polycrystal

A method to predict the shrinkage rate of a void centered at an equiaxial grain under hydrostatic pressure is developed. The rate process is controlled by lattice diffusion under the combined influence of void surface energy, grain boundary interface energy and elastic energy stored in the solid. A dimensionless loading parameter that controls the void evolving is introduced. Below a certain value of this parameter the void will be rounded and is stable. Then the shrinkage behavior of the voids is described by the parameters controlling the lattice diffusion. It is found that only gas-free voids could be totally eliminated through lattice diffusion; for a gas-filled void, the internal pressure produced by the gas firstly retards the rate of the shrinkage and eventually stops the shrinkage process as it becomes high enough.