2020年10月27日，课题组一篇论文“Atomic scale understanding of the defects process in concurrent recrystallization and precipitation of Sm-Co-Fe-Cu-Zr alloys”被金属材料旗舰刊物ACTA MATERIALIA（IF=7.656）录用。论文第一作者是2020年由硕士转为博士研究生的宋欣同学，这也是他作为第一作者的第3篇论文。祝贺他！

工作简介：再结晶与析出相共生不仅是设计高性能结构材料的重要手段，也是开发高性能永磁材料的重要方法。由于再结晶晶粒和析出相长大相互影响，且涉及复杂的缺陷演化过程，认识缺陷的形成及演变对控制再结晶晶粒尺寸和析出相分布至关重要。本文以高温磁性最强的析出硬化型Sm-Co-Fe-Cu-Zr永磁材料为对象，研究了六角过饱和固溶体在时效过程中的非均匀析出（胞状析出）和再结晶共生行为，从原子尺度揭示了层错（可分解为不全位错）、空位和间隙原子等缺陷的形成与演变过程，发现其由扩散-位移型混合相变主导，澄清了该材料发现40多年以来胞状组织形成机制的争议。

Abstract:

     Identifying the defects process in concurrent recrystallization and precipitation during aging a supersaturated solid solution is essential for understanding their interaction mechanisms and for manipulating the microstructure, but was rarely done at the atomic scale. Herein, the concurrent recrystallization and precipitation in the supersaturated hexagonal Sm(Co, Fe, Cu, Zr)7.5 alloys were studied through detailed transmission electron microscopy investigations, where the recrystallization, growth of recrystallized subgrains (cells) and precipitates stem from the gradual formation and dissociation of defects, including basal stacking faults (SFs), vacancies and excess interstitial atoms. The diffusion-controlled glides of <a>-type partial dislocations associated with the SFs not only transform the matrix from the mixture of hexagonal Sm(Co, Fe, Cu, Zr)7 (1:7H) and Sm2(Co, Fe, Cu, Zr)17 (2:17H) to Sm-depleted rhombohedral Sm2(Co, Fe, Cu, Zr)17 (2:17R) cells but also provide continuous diffusion channels to reduce the point defects to form the Sm-enriched hexagonal Sm(Co, Fe, Cu, Zr)5 (1:5H) cell boundary precipitates and Zr-enriched rhombohedral (Sm, Zr)(Co, Fe, Cu)3 (1:3R) platelets. It indicates a diffusion-controlled displacive phase transformation mechanism, characterized by the composition-dependent 2:17R' intermediate phase due to incomplete basal slip and incomplete solute partitioning. The growth velocities of both recrystallized cells and precipitates are closely related to the defects density, being faster due to the high defects density at early stage, and being slower due to the reduced defects density at later stage. A basal slip model is proposed to explain the formation and dissociation of defects along with the stacking period change and the simultaneous formation of continuous atomic diffusion channels. These new findings may yield a deep understanding of the interaction between recrystallization and precipitation.