摘要
Impurity segregation at grain boundary（GB） can significantly affect the mechanical behaviors of polycrystalline metal. The effect of nickel impurity segregated at Cu GB on the deformation mechanism relating to loading direction is comprehensively studied by atomic simulation. The atomic structures and shear responses of Cu Σ9（114） 110 and Σ9（221） 110 symmetrical tilt grain boundary with different quantities of nickel segregation are analyzed. The results show that multiple accommodative evolutions involving GB gliding, GB shear-coupling migration, and dislocation gliding can be at play, where for the 2ˉ21ˉ shear of Σ9（114） 110 the segregated GBs tend to maintain their initial configurations and a segregated GB with a higher impurity concentration is more inclined to be a dislocation emission source while maintaining the high mechanical strength undergone plastic deformation for the 11ˉ4ˉ shear of Σ9（221） 110. It is found that the nickel segregated GB exerts a cohesion enhancement effect on Cu under deformation： strong nickel segregation increases the work of separation of GB, which is proved by the first-principles calculations.
Impurity segregation at grain boundary（GB） can significantly affect the mechanical behaviors of polycrystalline metal. The effect of nickel impurity segregated at Cu GB on the deformation mechanism relating to loading direction is comprehensively studied by atomic simulation. The atomic structures and shear responses of Cu Σ9（114） 110 and Σ9（221） 110 symmetrical tilt grain boundary with different quantities of nickel segregation are analyzed. The results show that multiple accommodative evolutions involving GB gliding, GB shear-coupling migration, and dislocation gliding can be at play, where for the 2ˉ21ˉ shear of Σ9（114） 110 the segregated GBs tend to maintain their initial configurations and a segregated GB with a higher impurity concentration is more inclined to be a dislocation emission source while maintaining the high mechanical strength undergone plastic deformation for the 11ˉ4ˉ shear of Σ9（221） 110. It is found that the nickel segregated GB exerts a cohesion enhancement effect on Cu under deformation： strong nickel segregation increases the work of separation of GB, which is proved by the first-principles calculations.
作者
刘湘月
张红
程新路
Xiang-Yue Liu;Hong Zhang;Xin-Lu Cheng(Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China;Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610065, China;College of Physical Science and Technology, Sichuan University, Chengdu 610065, China)
基金
supported by the National Key Research and Development Program of China(Grant No.2017YFA0303600)
the National Natural Science Foundation of China(Grant Nos.11474207 and 11374217)
