High Entropy Alloy (HEA) is an alloy in which multi-component elements are configured in almost equal ratios, unlike alloys in which a small amount of one or two elements is added to the main elements like conventional alloys. HEA is characterized by the random arrangement of atoms. Several HEAs form ductile solid solution structures involving face centered cubic (FCC) or body centered cubic (BCC) phases or mixtures of the two, instead of brittle intermetallic compounds. It has been reported that some HEAs have unique properties such as a high strength and high radiation resistance at elevated temperatures compared with conventional alloys. Those attractive physical and mechanical properties make HEAs potential candidates for high temperature fission or fusion structural applications. However, the studies on their radiation resistance at elevated temperatures relevant for potential nuclear energy applications is limited. It is hypothesized that the high mixing entropy of HEAs might influence point defect recombination in irradiated materials by modifying the distance of vacancy-interstitial recombination interaction, solute diffusivity, and other mechanisms, thereby producing different radiation stability compared to conventional single-phase alloys. Currently available austenitic stainless steels for light water reactors (LWRs) do not appear to exhibit sufficient radiation damage resistance for extended operation at elevated temperatures in next generation nuclear energy systems.
In this talk, we focus on the microstructural changes in electron- or ion-irradiated FCC-type HEAs and CSAs in order to better understand the mobility of the point defects and the effect of SFE on damage evolution under irradiation.