Short-range ordering induced serrated flow in a carbon contained FeCoCrNiMn high entropy alloy.

Phase stability of high entropy alloys depends significantly on the compositional constituents. Here we report the joint effects of interstitial carbon and compositional inhomogeneity on the mechanical response, particularly the serrated flow, of a carbon doped FeCoCrMnNi high entropy alloy. Detailed microstructural characterizations show that compositional inhomogeneity, including heterogeneous short-range ordering structure, is formed in carbon doped FeCoCrNiMn HEA. The serrated flow on the stress-strain curves of carbon doped alloy at room temperature is attributed to the dynamic strain aging, which is presented based on the complex interactions between carbon, stacking faults and short-range ordering at the atomic scale.