Microstructural evolution, phase selection and properties of CoCrCuFeMnxNi high-entropy alloys

Manganese was added to face-centered-cubic (fcc) high-entropy CoCrCuFeNi alloy to investigate the effects of Mn content on the microstructures, phase selection, and properties of CoCrCuFeMnxNi. CoCrCuFeMnxNi showed typical dendrite and interdendritic structures, and nanoprecipitates including Cu-rich cubic and Cr-rich acicular ones, were obtained in the interdendritic region. Calculated phase-selection-related parameters indicated that the formation of fcc phase was favored. Although two fcc structures were detected by X-ray diffraction, the interdendritic region showed body-centered-cubic, Cr-rich nanoprecipitates when x < 0.5. It is worth noting that the CoCrCuFeMn2.0Ni interdendrites showed an amorphous phase. CoCrCuFeMnxNi showed considerable ductility and increasing compressive strengths with increasing Mn content.