The Thermal Stabilization Effect of Inert Gas Atoms on Irradiation Hardening in Vanadium Alloy

Vanadium (V) alloys are attractive candidate materials for tritium breeding modules (TBM) of blankets in fusion reactors. However, irradiation-induced hardening and embrittlement give rise to significant challenges for the application of V alloys in advanced nuclear reactors, particularly in the presence of inert gas atoms. In this study, V-5Cr-5Ti alloys were irradiated by 122 MeV Ne ions (at doses of 0.1 and 0.3 dpa) and 352 MeV Fe ions (at doses of 0.06, 0.20 and 0.35 dpa) at a temperature around 100 degrees C, and subsequently annealed at the temperature ranging from 212 to 500 degrees C. During the annealing process, the hardening produced by Fe ion irradiation started to recover at a temperature higher than 212 degrees C and was eliminated at a temperature higher than 375 degrees C. For the sample with Ne ions irradiation, the irradiation hardening of the sample with 0.3 dpa can be sustained at a temperature up to 450 C-o, but an evident reduction of hardening in the sample with 0.1 dpa was observed after annealing at 212 C-o. This suggested that the existence of inert gas atoms had a thermal stabilization effect on irradiation hardening, but it required a critical atom concentration. The different annealing behaviors of irradiation hardening at different doses under Ne ions irradiation were considered to be from the coupling effect of bubble growth and the interaction between interstitial clusters and Ne atoms.