A gradient B2-BCT transition introduced by deformation in eutectic high-entropy alloy

Eutectic high-entropy alloys (EHEAs) exhibit promising characteristics for achieving both high strength and good ductility owing to their diverse deformation mechanisms. In this study, a gradient B2-body-centerd tetragonal (BCT) phase transformation was observed in a deformed Al19Fe20Co20Ni41 (at. %) EHEA. The X-ray diffraction patterns indicate a gradual transformation from the B2 phase to the BCT phase, a process significantly influenced by the applied strain during tensile testing. The gradient transition region between B2 phase and BCT phase occurs within a single grain, where the lattice constant changes step by step. Such a mechanism holds huge potential for enhancing the mechanical properties of EHEAs.