Irradiation damage versus lattice distortion in AlNbTiVCrx (x = 0, 0.5, 1) high-entropy alloys from first-principles calculations and irradiation experiments

Severe lattice distortions and rough energy landscapes were found in low-density, refractory AlNbTiVCrx (x = 0, 0.5, 1) high-entropy alloys (HEAs) via first-principles calculations. The corresponding samples were irradiated by 5 MeV Xe ions to fluences of 3.3 × 1014 ions/cm2 at 600 ℃. Fundamental irradiation behaviors were studied using transmission electron microscopy and nanoindentation. No phase decomposition was found after irradiation as well as void. The irradiation-induced dislocation loop size decreases, and the density increases with the increasing Cr content. This finding is attributed to the fact that Cr aggravates lattice distortion and roughens energy landscapes in the AlNbTiVCrx system, which will interrupt the long-distance migration of self-interstitials and delay their accumulation. Nanohardness increments exhibit good consistency with the product of dislocation loop size and density. This work provides an insight into the combination of atomic simulation and irradiation experiments for better understanding of the irradiation behaviors of refractory HEAs, and a possibility to modify defect evolution by regulating the compositional complexity.