Stability and shrinkage of a cavity in stressed grain

摘要

A cavity in a stressed grain may change its shape through surface diffusion and volume through lattice diffusion. A suitable thermodynamic potential is established, from which a dimensionless loading parameter that controls the cavity evolution is introduced. Above a critical value of this parameter the cavity collapses to a crack; below that the cavity will stay stable. Then, the shrinkage rate, thereby the healing time, of a spherical cavity is derived as a function of external applied pressure and internal gas pressure. The effects of the applied pressure and the internal pressure on the rate process of the cavity are discussed.