Stability Prediction of AlCoCrFeMo 0.05 N 2 High Entropy Alloy by Kinetic Monte Carlo Method

Abstract

High entropy alloy (HEAs) are most likely to be the next-generation superalloy. However, the instability of solid solution, especially FCC type solid solution, in HEA limits the development of high entropy superalloys (HESAs). Due to the complex and large systems of HEAs and the lack of HEAs databases, the stability prediction of a solid solution in a HEA becomes a huge challenge. Here, Kinetic Monte Carlo simulation (KMC) was used to study the metastability in HEA, which required almost only parameters obtained from ab initio calculations rather than empirical HEAs databases. For the first time, the phase separation of AlCoCrFeMo0.05 N 2 alloy was predicted accurately by KMC method, showing that Al atoms preferentially occupied vacancies and eventually formed (Ni, Al)-rich phase. And the vacancies in the sample eventually formed a vacancy group in the (Ni, Al)-rich phase, promoting the transition of the phase from FCC to BCC structure.