Influence of V Substitution Ti on the Microstructure and Mechanical Properties of Al5Nb20Ti(45−x)Zr30Vx Lightweight Refractory High‐Entropy Alloys

In this study, new refractory high‐entropy alloys of Al 5 Nb 20 Ti (45− x ) Zr 30 V x ( x = 0, 5, 10, and 15 at.%, described as V0, V5, V10, and V15) are designed by the strategy of gradient substitution of Ti by V. The effects of V content on the microstructure and mechanical properties of the alloys are systematically investigated. The results show that the as‐cast alloys all exhibit a single body‐centered cubic (BCC) structure. The introduction of V element significantly reduces the lattice parameter and induces sever lattice distortion, which enhances the room‐temperature yield strength from 809 MPa for V0 alloy to 1248 MPa for V15 alloy. However, excessive V content (15 at.%) leads to a reduction in plasticity, with a fracture strain of 29%. High‐temperature compression test (800 °C) shows that the yield strength of V15 alloy (194 MPa) increases by 104% compared to that of V0 alloy (95 MPa). Microstructure analysis shows that dynamic recrystallization and dynamic recovery dominate the softening process at high temperatures.