Phase-field modeling of helium bubble evolution in nickel-graphene nanocomposite

Metal-graphene (Gr) nanocomposites are regarded as potential anti-irradiation advanced materials for Gen-IV nuclear reactors. In this work, a phase-field model was proposed to simulate helium (He) bubble evolution of nickel-Gr (Ni/Gr) nanocomposite during constant irradiation at 800K. Ni/Gr nanocomposite presented an earlier onset time of He bubble nucleation but eventually formed bubbles with smaller size and lower density than those of pure Ni. The early He bubbles nucleated along Ni/Gr interfaces, while a He depletion zone formed nearby consequently, which confirmed that Ni/Gr interfaces inhibit He bubble growth. The effects of vacancies and He atoms on the He bubble growth rate were also quantitatively analyzed. The amount of irradiation-induced vacancies acted as an effective rate-controlling factor that determined the bubble growth rate with respect to the He atoms.