Effects of B2 ordered structure on the mechanical properties of TiZrHfCoNiCu high-entropy alloy

High-entropy alloys (HEAs) were once considered to be typical disordered solid solutions with various atoms randomly distributed in a lattice. Recent studies have found that owing to the chemical complexity of multiple primary elements, HEAs may also form ordered structures that directly influence their mechanical properties. In this study, B2-ordered and body-centered-cubic-disordered structures of TiZrHfCoNiCu HEAs were established using the special quasi-random structure method. The results of first principles calculations and ultrasonic wave velocity measurements indicated that the B2-ordered TiZrHfCoNiCu HEA exhibited superior phase stability, structural stability, and mechanical properties such as strength and hardness. Significantly, the results of this study revealed the physical mechanisms underlying the excellent mechanical properties of ordered HEAs and can guide their design and development accordingly.