Tensile creep behavior of an equiatomic CoCrNi medium entropy alloy

Tensile creep behavior of the CoCrNi medium entropy alloy in a temperature range of 973–1073 K was investigated in this study. According to the fitted stress exponent and activation energy, dislocation climb and lattice diffusion are proposed to be the dominated creep deformation mechanism for this alloy. During creep tests, the plate-like Cr-rich σ phase forms along the grain boundaries of the originally single-phase face-centered-cubic (FCC) CoCrNi alloy. It is suggested that low stacking-fault energy and local chemical ordering be responsible for the superior creep resistance and lifetime as opposed to that of the CoCrFeMnNi alloy.