Friction stir welding of γ-fcc dominated metastable high entropy alloy: Microstructural evolution and strength

A systematic study of butt friction stir welding of a recently developed Cu-containing metastable high entropy alloy (HEA) was conducted. Different zones of the weld were evaluated using mechanical testing, microstructural characterization, and differential scanning calorimetry (DSC). The nugget exhibited high tensile strength as a result of the refined equiaxed microstructure. Interestingly, the heat affected zone, which is known to be the weakest region, exhibited an excellent combination of strength and ductility as compared to the base metal. DSC was explored as a novel and quick technique to obtain enthalpy information and thus understand the TRIP effect.