The effect of irradiation-induced point defects on energetics and kinetics of hydrogen in 3C-SiC in a fusion environment

摘要: 3C-SiC is a promising candidate for structural material of nuclear fusion reactors, and H, T, D irradiation often causes undesired volume swelling, bubble formation, degradation the mechanical properties material. However, underlying mechanisms these processes are still not well understood. We thereby carried out systematical first-principles calculations to investigate interaction H with irradiation-induced point defects in 3C-SiC. Our results show that both self-interstitial atoms vacancies can act as trap sites which effectively influence retention its isotopes Self-interstitial C Si up six five atoms, respectively. A vacancy eight two H2 molecules formed, while only four no molecule formation. The accumulation forming vacancy-hydrogen clusters may nucleation site bubbles or blisters result instability around vacancy, growth bubbles. Both significantly slow down diffusion energy barriers from reach respectively 3.40 2.13 eV, much higher than bulk. These explain why calculated activation perfect smaller experimental values. helpful understanding micro-mechanism formation experimentally observed