Radiation-assisted chemical short-range order formation in high-entropy alloys

Abstract

The chemical short-range order (CSRO) in a face-centered cubic equiatomic NiCoFeCrMn high-entropy alloy was revealed directly from advanced transmission electron microscopy in this work. Further, instead of controlling CSRO by conventional heat treatment, we show a new possibility of tailoring CSRO by radiation. The multiple types of atoms in such high-entropy system are more prone to form CSRO under radiation compared to that only under thermodynamic equilibrium conditions, due to the rearrangement of the chemical ordering during the non-equilibrium thermal spike period and the radiation-enhanced diffusion mechanism. Our results show an increase in the fraction of CSRO area by ∼45% after high-temperature irradiation with a dose of 50 DPA. Accordingly, we demonstrated that enhanced CSRO can be achieved by controlling the irradiation dose and temperature, which provides a new route to explore the kinetic evolution and effect of CSRO in complex alloy systems.