Phase-Field Simulation of Void Evolution Under Irradiation: A Reaction–Diffusion Model

We propose a reaction–diffusion phase-field model to simulate the microstructure evolution of voids in systems with low vacancy concentration under irradiation. In this model, void growth and shrinkage are governed by reactions between vacancies/interstitials and the void surface, while an order parameter is introduced to describe void morphology. By avoiding the sharp increase in vacancy concentration near the void interface, the model enables the simulation of void evolution in low vacancy concentration matrices over enlarged time scales. When combined with classical nucleation theory, the approach enables quantitative, accurate three-dimensional simulations of slow void evolution processes, achieving comparability with rate theory models. Numerical results demonstrate that the model accurately captures the evolution of voids under dilution conditions. At the same time, its inherent scalability makes it broadly applicable to other material systems characterized by low solute concentrations.