A novel stress-induced martensitic transformation in a single-phase refractory high-entropy alloy

Abstract High-entropy alloys (HEAs) provide a new perspective to design metastable alloys with the stress-induced martensitic transformation (SIMT) for overcoming the strength-ductility trade-off. Here, we report a novel SIMT, orthorhombic to hexagonal close-packed martensite, in a single orthorhombic refractory HEA (Ti16Zr35Hf35Ta14 RHEA), showing a good yield strength-ductility matching. The analysis of the elastic distortion energy (∆Eels) of Ti16Zr35Hf35Ta14 and several other RHEAs reveals that severe lattice distortion is a key factor which causes this SIMT. Combined the “d-electron alloy design” approach with the ∆Eels, the phase configuration and SIMT path in RHEAs can be well predicted. Our work brings new insights between the lattice distortion and SIMT of RHEAs, benefiting the metastable alloy development.