PNNL

Abstract

We present a phase-field model that simulates vacancy diffusion in a solid with a strong inhomogeneity of vacancy mobility, which is used to study void migration via bulk and surface diffusion in a temperature gradient. The simulation results demonstrate that voids migrate up the temperature gradient and the migration velocity varies inversely with the void size in agreement with theory. The simulations also show the capability of the developed model for investigating the effect of surface diffusion, temperature gradient, and vacancy concentration on the void migration velocity and which are shown in this study. A potential application of the model is shown in studying the kinetics of the void migration and the formation of central hole in the nuclear fuels.