Radiation Resistance in Multicomponent Equiatomic Alloys

Multicomponent equiatomic alloys, including medium- and high-entropy alloys (MEAs and HEAs), have been demonstrated notably high irradiation resistance, which is commonly attributed to their extraordinary interstitial behaviors or chemical disorder. The recent progress in simulating radiation damage and microstructural evolution in multicomponent equiatomic alloys will be discussed and some interesting results will be highlighted. These simulations provide the detailed mechanisms on the generation and evolution of irradiation-induced defects in face-centered cubic MEAs and HEAs to understand the new mechanisms of their irradiation tolerance. As compared with Ni, the primary radiation damage produced by displacement cascades in a HEA-NiCoCrFe exhibits delayed defect accumulation and enhanced defect suppression, which is attributed to the stronger thermal spike, lower thermal conductivity, and smaller binding energy of interstitials. In addition, the interaction of the displacement cascades with a pre-existing stacking fault tetrahedron (SFT) in a MEA-NiCoCr and Ni is employed to understand their differences of void swelling. Also, we have developed object kinetic Monte Carlo based long-time dynamics, which can be used to simulate void formation and defect accumulation at experimentally relevant time-scale for the first time in multicomponent equiatomic alloys.