Yan Zhengwei, Shi Shujing, Sang Peng, Li Kaiyue, Qin Qingqing, Li Yongsheng
School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials Technology, Nanjing 210094, China.
Nanomaterials (Basel). 2023 Jan 22;13(3):456. doi: 10.3390/nano13030456.
Irradiation-induced point defects and applied stress affect the concentration distribution and morphology evolution of the nanophase in Fe-Cr based alloys; the aggregation of point defects and the nanoscale precipitates can intensify the hardness and embrittlement of the alloy. The influence of normal strain on the coevolution of point defects and the Cr-enriched α' nanophase are studied in Fe-35 at.% Cr alloy by utilizing the multi-phase-field simulation. The clustering of point defects and the splitting of nanoscale particles are clearly presented under normal strain. The defects loop formed at the α/α' phase interface relaxes the coherent strain between the α/α' phases, reducing the elongation of the Cr-enriched α' phase under the normal strains. Furthermore, the point defects enhance the concentration clustering of the α' phase, and this is more obvious under the compressive strain at high temperature. The larger normal strain can induce the splitting of an α' nanoparticle with the nonequilibrium concentration in the early precipitation stage. The clustering and migration of point defects provide the diffusion channels of Cr atoms to accelerate the phase separation. The interaction of point defect with the solution atom clusters under normal strain provides an atomic scale view on the microstructure evolution under external stress.
辐照诱导的点缺陷和外加应力会影响铁铬基合金中纳米相的浓度分布和形态演变；点缺陷的聚集以及纳米级析出物会加剧合金的硬度和脆化。利用多相场模拟研究了Fe-35 at.% Cr合金中正向应变对点缺陷与富Crα'纳米相共同演变的影响。在正向应变下，点缺陷的聚集和纳米级颗粒的分裂清晰可见。在α/α'相界面处形成的缺陷环缓解了α/α'相之间的共格应变，降低了正向应变下富Crα'相的伸长率。此外，点缺陷增强了α'相的浓度聚集，在高温压缩应变下这种现象更为明显。较大的正向应变会在早期析出阶段诱导具有非平衡浓度的α'纳米颗粒发生分裂。点缺陷的聚集和迁移提供了Cr原子的扩散通道，加速了相分离。正向应变下点缺陷与溶质原子团簇的相互作用为外部应力作用下的微观结构演变提供了原子尺度的视角。
