Effects of local chemical ordering on defect evolution in NiFe concentrated solid solution alloy

Abstract

Single-phase concentrated solid solution alloys (SP-CSAs), including high-entropy alloys (HEAs), are promising candidates for structural materials in nuclear reactors. Recent studies have demonstrated that local chemical ordering (LCO) is an important structural feature in these alloys, which can significantly affect defect evolution. The presence of LCO leads to elemental rearrangement in CSAs and results in distinct interfaces separating the ordered and disordered phases. In this work, we study the role of LCO and order/disorder interface on defect evolution in NiFe CSAs. Our results indicate that the interface can act as defect sinks in the defect recombination stage. At the diffusion stage, defect evolution is strongly affected by LCO due to chemically biased diffusion in CSAs and preferential diffusion pathways of defect clusters. We further show that the degree of LCO and the dimensions of the LCO domains play significant roles in defect clustering and annihilation behavior. These results provide fundamental insight into the influence of LCO on defect evolution in CSAs and pave ways for designing highly irradiation-tolerant structural materials for nuclear applications.