Analyzing irradiation-induced creep of silicon carbide

Irradiation creep, which is among the major lifetime-limiting mechanisms for nuclear structural materials, is stress-driven anisotropic plastic deformation occurring in excess of thermal creep deformation in radiation environments. In this work, experimental irradiation creep data for beta-phase silicon carbide (SiC) irradiated at intermediate temperatures is analyzed using a kinetic model with an assumed linear-coupling of creep strain rate with the rate of self interstitial atom (SIA) absorption at SIA clusters. The model reasonably explains the experimentally observed time-dependent creep rate of ion-irradiated SiC and swelling evolution of ion- and neutron-irradiated SiC. Bend stress relaxation behavior during irradiation was then simulated using the developed model to examine the experimental data obtained by neutron irradiation experiments. Recommended directions of future experiment are provided to further verify and improve the models and assumptions in this work.