Kinetic stability against void coarsening in molybdenum

The measured rate of increase of void size in molybdenum with annealing time is found to be slower than expected from the Wagner analysis of diffusion-controlled coarsening. The Wagner theory of surface-reaction-control is also compared with ripening data. The determined surface kinetic parameters are compared with vacancy diffusivities and are found to be not unrealistic. Furthermore, a measured decrease in void volume during annealing indicates that total void volume is not conserved. These observations support the conclusion that void coarsening is influenced by more than one rate controlling mechanism. A numerical solution to the void annealing problem is obtained and the specific role of volume diffusion, surface kinetics, and annealing of vacancies to sinks other than voids is calculated