Lightweight Zr1.2V0.8NbTi Al high-entropy alloys with high tensile strength and ductility

Abstract

High-entropy alloys (HEAs) provide a new perspective to design novel lightweight alloys, whereas the complex precipitates in current lightweight HEAs (LHEAs) generally limit the mechanical properties. By controlling Ti and Al, the B2 and C14 Laves precipitates in Zr 1.2 V 0.8 NbTi x Al y (Ti x Al y ) LHEA system were successfully suppressed, and a series of LHEAs with outstanding specific yield strength-ductility matching were designed. Especially, with the same deformability (tensile ductility over 25%), the specific yield strength of Ti3.6Al0.6 LHEA is over 40% higher than current developed HEAs. The excellent mechanical properties are attributed to be benefited by a combination of solid solution strengthening and chemical short-range order strengthening. Our results bring new insights into the phase stability and precipitation suppression of HEAs, which is constructive for the novel lightweight alloy development. • Ti–Al control achieved both precipitate suppression and lightweight in HEA design. • A specific strength improvement of 40% was achieved in HEAs with ductility over 25%. • Strengthening of solid solution and chemical short-range order benefit the property.