Effect of precipitation on the kink deformation and damage in a (WTaNb)₅₀Hf₅₀ body-centered-cubic high-entropy alloy at high strain rate

Understanding the deformation and damage behavior of precipitation hardening body-centered cubic (BCC) high-entropy alloys (HEAs) at high-strain-rate is critical for their applications in extreme loading conditions. Here we report the effect of precipitation on kink deformation and damage in a (WTaNb)₅₀Hf₅₀ alloy at high strain rate. We find that the dynamic ultimate compressive strength of aged alloy reaches 2400 MPa due to the precipitation hardening. Compared with the as-cast alloy, the presence of precipitation increases the crystallographic misorientation of kink bands without altering crystallographic feature under not only quasi-static but also dynamic loadings. Furthermore, due to the occurrence of more cracks in precipitation hardening alloy, the failure mode shifts from the combination of adiabatic shear band and intergranular fracture in the as-cast alloy to a single intergranular fracture in the precipitation hardening alloy, leading to the reduction of the dynamic fracture strain by 8 %.