Unveiling the mechanism of tuning elemental distribution in high entropy alloys and its effect on thermal stability

Abstract

The issue of elemental distribution such as chemical short range order (SRO) in high entropy alloys (HEAs) has garnered increased attention in both experimental and theoretical realms. A comprehensive and urgently required elucidation of this atomic-level phenomenon is the focus of this study. In this work, we systematically analyzed atomic-level information, involving atomic volume, charge transfer, local chemical ordering and atomic stress in 3d HEAs. We assess the hotly debated issue by attributing it to Cr atoms with negative atomic stress in the sublattice site, whereas other atoms with positive atomic stress have larger electronegativity and greater atomic volume, through which the interplay of positive and negative atomic stresses balances the local atomic environment. Additionally, we assume that Mn promotes the homogeneity of the HEA and the temperature-dependent chemical SRO enhances the thermal stability of HEAs. Our work contributes to advancing our understanding of the mechanistic aspects of elemental distribution in HEAs and their thermodynamic implications.