Phase-field modeling of void formation and growth under irradiation

The application of phase-field modeling to void formation and growth under irradiation is analyzed. Here our focus is on the energy of the diffuse interfaces of the void system, which is customarily modeled by a Ginzburg-type gradient energy term with a parameterized coefficient. To correctly emulate the kinetics of void formation, the corresponding free-energy change is calibrated against the classical nucleation model, where the void–matrix boundary is well defined. We find that the gradient-energy coefficient may be conveniently treated as a constant independent of void size, even for voids down almost to the atomic size. We also find that the diffuse void interface in phase-field simulation has to be treated on an ultrafine spatial scale to reproduce the void energetic characteristics and growth behavior derived from the sharp boundary approach.