A ductile Nb40Ti25Al15V10Ta5Hf3W2 refractory high entropy alloy with high specific strength for high-temperature applications.

Refractory high entropy alloys (RHEAs) with good high-temperature softening resistance have been revealed as promising candidates for high-temperature structural materials. In this work, a low-density ductile RHEA, Nb 40 Ti 25 Al 15 V 10 Ta 5 Hf 3 W 2 , has been developed. The RHEA with a BCC matrix and B2 nanoprecipitates exhibits excellent specific yield strength. The compressive specific yield strength (σ 0.2 /ρ) at 1073 K is as high as 83.2 MPa g−1 cm3. The different deformation behaviors during compression at 1073 K and 1273 K are also identified. The dislocation-dominated deformation provides the initial strain hardening capability, and then microcracks and dynamic recovery accelerate the transition from strain hardening to softening at 1073 K. While the diffusion-controlled dislocation annihilation and continuous dynamic recrystallization (DRX) are the dominant reasons for persistent strain softening at 1273 K. Our work not only reports a promising RHEA with excellent high-temperature properties, but also promotes the development of RHEAs for high-temperature applications. • A low-density ductile RHEA, Nb 40 Ti 25 Al 15 V 10 Ta 5 Hf 3 W 2 , has been developed. • The RHEA has BCC matrix and B2 nanoprecipitates. • The RHEA possesses the superior SYS (σ 0.2 /ρ = 83.2 MPa g−1 cm3) at 1073 K. [ABSTRACT FROM AUTHOR]