Bauschinger effect in Gd micro-alloying metastable high-entropy alloy

Abstract

To investigate Bauschinger effect in metastable high-entropy alloys with strain-induced FCC → HCP phase transformation, we designed a series of Gd micro-alloying non-equiatomic metastable high-entropy alloys. The results show that all tested alloys have asymmetrical tension-compression properties exhibiting the obvious Bauschinger effect, which is related to the different levels of phase transformation in compression and tension owing to different deformation textures. Excessive phase transformation suppresses the increase in pile-up density of geometrically necessary dislocations (GNDs), resulting in a back stress relaxation effect. The inverse phase transformation observed by quasi in-situ EBSD proves the instability of the HCP phase. The established kinetic model points out limitation of the classical back stress measurement method in metastable high-entropy alloys.