Stability prediction of AlCoCrFeMo0.05Ni2 high entropy alloy by Kinetic Monte Carlo method

High entropy alloys (HEAs) are most likely to be the next-generation superalloy. However, their development are often limited by the instability of a solid solution in the alloys especially for 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 (KMC) simulation was used to investigate the metastability in AlCoCrFeMo0.05Ni2 HEA, in which atomic parameters such as interatomic and interatomvacancy interaction potential were adopted to study the atomic diffusion behavior during annealing by simulating vacancy migration. For the first time, the phase separation behavior in a FCC solid solution of the AlCoCrFeMo0.05Ni2 HEA was predicted by the KMC method, in which Al atoms were found to occupy preferentially vacancies and eventually formed the (Ni, Al)-rich phase during annealing at 973 K. And the vacancies, captured by the (Ni, Al)-rich phase, promoted the growth and transition of the phase from FCC to BCC structure.

Automated summary

The study used Kinetic Monte Carlo (KMC) simulation to investigate the metastability in AlCoCrFeMo0.05Ni2 HEA and successfully predicted the phase separation behavior in a FCC solid solution. During annealing at 973 K, Al atoms were found to occupy preferentially vacancies and eventually formed the (Ni, Al)-rich phase, promoting the growth and transition of the phase from FCC to BCC structure.