| Abstract Scope |
Radiation-induced segregation (RIS) and cavity growth often occur concurrently in irradiated alloys. Experimental studies have shown that RIS can suppress cavity growth in certain materials. However, few studies have focused on simulating the coupled evolution of RIS and cavity growth, leaving knowledge gaps in understanding the interaction between these two important phenomena.
In this work, we developed a one-dimensional sharp-interface model to simulate the mutual influence between RIS and cavity growth. To address the computational challenges caused by the moving cavity surface, we transformed the absolute spatial coordinates into relative coordinates, allowing us to apply boundary conditions directly at the cavity surface. Using pure nickel (Ni) and a nickel–50 at.% iron alloy (Ni50Fe50) as model systems, we demonstrated that Ni enrichment significantly suppresses cavity growth. Under identical irradiation conditions (0.8 dpa at 500 °C), the cavity radius in Ni reached 1.2 nm, whereas in Ni50Fe50, it only grew to 0.9 nm. This reduction is primarily attributed to decreased local vacancy mobility and vacancy back-diffusion driven by composition gradients near the cavity. When RIS was excluded from the simulation, cavity growth in Ni50Fe50 approached that of pure Ni, confirming the suppressive role of RIS. Additionally, our results showed that cavity growth has a negligible effect on RIS near cavity surfaces, as RIS saturates at relatively low doses in these regions. |