Reducing Hf Enables a Cost‐Effective HfNbTiZr Refractory High‐Entropy Alloy With Enhanced Room‐Temperature Strength‐Ductility and High‐Temperature Strength

Refractory high‐entropy alloys have attracted substantial attention owing to their great potential for high‐temperature applications; however, their limited room‐temperature plasticity and the high cost of constituent elements have hindered their practical application. In this study, we systematically investigated the microstructure, room‐temperature and high‐temperature mechanical properties, strengthening mechanisms of HfNbTiZr‐based alloys with reduced Hf (expensive and high‐density element) content, which exhibit improved room‐temperature plasticity. The results indicate that Hf x (NbTiZr) 100‐ x ( x = 0, 5, 10, 15, 20, 25) alloys possess a body‐centered cubic (BCC) structure. The Hf‐free NbTiZr alloy exhibits improved room‐temperature and high‐temperature yield strengths compared with the Hf‐containing counterpart Hf 25 . Moreover, reducing the high‐density Hf element significantly decreases the overall alloy density. This work demonstrates that the strategic reduction of high‐cost, high‐density elements presents a viable and effective strategy for developing refractory high‐entropy alloys that simultaneously fulfill the stringent requirements of mechanical performance and economic viability for industrial applications.