A metastable lightweight high entropy alloy with the transformation induced plasticity

Body-centered cubic (BCC) high entropy alloys (HEAs) usually have poor ductility, limiting their engineering application. Here we present a TiZrNbAl non-equal atomic-ratio HEA (Z25) which shows martensitic transformation during tensile deformation. This transformation effectively improved the uniform ductility to around 17%. The gradually induced martensite lamella shows the “dynamic Hall-Petch” effect during transformation, which reduces the mean free path of dislocation slip, resulting in Z25 alloy with excellent ductility and remarkable work hardening effect.