Mixing entropy threshold for entropy-tailored materials

Abstract

To determine the effect of mixing entropy on multicomponent alloys and to find the mixing entropy threshold for entropy-tailored materials, including high-entropy alloys and medium-entropy alloys, the microstructure and mechanical properties of 23 Ti–Zr–Nb–V alloys were investigated. The Laves phase content of Ti–Zr–Nb–V alloys was obtained using image recognition technology. According to the component threshold for Laves phases and HCP phase disappearance, V(Nb)–Zr(Ti) pseudo-binary phase diagrams, which can predict the phases of ternary Ti–Zr–V and Zr–Nb–V alloys, were established. By comparing the Laves phase content in Ti–Zr–Nb–V alloys obtained from experimental statistics, pseudo-binary phase diagrams and thermodynamic calculations, the ΔSmix threshold for entropy-tailored materials was 1.10–1.21R. The dependence of the yield strength and fracture strain of the Ti–Zr–Nb–V alloys further reveals that the mechanical properties of entropy-tailored alloys are essentially controlled by ΔSmix.