Chemical environment effects on the size of mono-vacancy in CrFeCoNi alloy

Abstract

Atomic studies of mono-vacancy are crucial for comprehending the mechanisms governing the related macroscopic properties of materials. High-entropy alloys (HEAs) manifest unique properties arising from a complex, localized, disordered chemical environment and distinctive site lattice distortions. In this study, the effects of chemical environment on the size of vacancy point defects in equiatomic CrFeCoNi alloy are investigated using Density Functional Theory through positron annihilation lifetime (PL) calculations. To better understand the nature of local lattice distortion, a similar atomic environment method is employed for supercell construction. Our findings reveal a significant inverse relationship between the PL of single-vacancy in CrFeCoNi HEA and the number of its first nearest neighbor Cr atoms. The underlying mechanisms in the perspective of local atomic mismatch and electronic structures are discussed.