Yan Zhengwei, Shi Shujing, Li Yongsheng, Chen Jing, Maqbool Shahid
School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
Phys Chem Chem Phys. 2020 Feb 14;22(6):3611-3619. doi: 10.1039/c9cp06247e. Epub 2020 Jan 29.
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.
辐照诱导的点缺陷影响Fe-Cr合金的相分解和形态演变，导致硬度增加和脆化。利用相场模拟研究了点缺陷与富Cr纳米级α'相的共同演化，并阐明了点缺陷与富Cr纳米级颗粒对动力学演化的相互影响。研究发现，空位和间隙原子的聚集早于α'相的分离，点缺陷从初始聚集位置迁移到α/α'相的界面，并随着α'相的生长在α'相周围积累形成缺陷浓度环。此外，随着初始缺陷浓度的增加，通过空位扩散机制加速了相分离，富Cr颗粒的分离也促进了点缺陷的聚集。在温度升高时，点缺陷对相分离有显著影响。
