Vacancy and interstitial atom evolution with the separation of the nanoscale phase in Fe-Cr alloys: phase-field simulations.

Point defects induced by irradiation affect the phase decomposition and morphology evolution of Fe-Cr alloys, which results in the increase of hardness and embrittlement. The coevolution of point defects and the Cr-enriched nanoscale α' phase was studied by using phase-field simulations, and the interactive influence of point defects and Cr-enriched nanoscale particles on the kinetics evolution was clarified. It is found that the clustering of vacancies and interstitial atoms is earlier than the separation of the α' phase, and the point defects migrate from the initial cluster position to the interface of the α/α' phases, and accumulate into a defect concentration loop around the α' phase with the growth of the α' phase. In addition, with the increase of the initial defect concentration, phase separation is accelerated via the vacancy diffusion mechanism, and also the separation of Cr-enriched particles promotes the clustering of point defects. Point defects show a significant influence on phase separation with elevated temperature.