Understanding the tensile ductility of a novel low-activation BCC high-entropy alloy deformed at intermediate temperature

Low-activation body-centered cubic (BCC) high-entropy alloys (HEAs) often possess poor tensile ductility. Here we report a novel low-activation VCrFeMn_0.33 BCC HEA that exhibits good tensile ductility at 650 °C and above. However, it shows poor tensile ductility at 500 °C and below, indicating that the ductile-to-brittle transition temperature (DBTT) of the current HEA falls between 500 °C and 650 °C. At temperatures above DBTT, the current BCC HEA deforms via dislocation glide, similar to the tensile deformation observed in conventional ductile BCC alloys, which is rarely reported for non-refractory BCC HEAs.