Evolution of local lattice distortion under irradiation in medium- and high-entropy alloys

A major challenge for future nuclear reactors is to design nuclear materials that can sustain extremely prolonged radiation damage. Local lattice distortion, considered as a core effect of high-entropy alloys (HEAs), can suppress the growth of radiation defects to control radiation performance. However, local lattice distortion in HEAs is rarely quantitatively measured. Here we employed total scattering technique to study the local structure of the face-centered cubic (fcc) equiatomic FeCoNiCr MEA, and FeCoNiCrMn and FeCoNiCrPd HEAs before and after ion irradiation. Their local lattice distortions were quantitatively evaluated based on the difference of lattice constant between the local structure and the average structure. We revealed that the mean local lattice distortion in the pristine samples varies in the following order: FeCoNiCr