Evading dynamic strength and ductility trade-off in a high-entropy alloy via local chemical ordering

Abstract

Strength-ductility trade-off in metals is sever under dynamic loading due to the strain rate effect and adiabatic shear failure. Here, we demonstrate that both strength and ductility progressively increase with increasing strain rate in a body-centered cubic TiZrNbTa refractory high-entropy alloy. We find that a prominent strain rate effect occurs, with a yield strength of 1879 ± 10 MPa at a strain rate of 6500 s−1, which is double that compared to a strain rate of 10−3 s−1. Simultaneously, Zr- and (Nb, Ta)-enriched local chemical ordering stimulates dislocation slip, enhancing homogeneous deformation capacity and adiabatic shear resistance under high strain rates. These findings suggest the importance of local chemical ordering to the dynamic properties of high-entropy alloys, and offer a way to develop metallic materials with improved dynamic mechanical properties.