Atomic-resolution studies on reactions between basal dislocations and {10■2} coherent twin boundaries in a Mg alloy
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2021年第7期
论文作者：Huhu Su Xinzhe Zhou Shijian Zheng Hengqiang Ye Zhiqing Yang
文章页码：28 - 35
摘 要：Reactions between basal 〈a60〉 dislocations and {10■2} coherent twin boundaries（CTBs） in a Mg alloy were studied with atomic resolution. Individual dislocation-CTB reactions produced steps with residual dislocations and multiple t winnin g dislocations（TDs） gliding away, consequently resulting in TB migration. Reactions between {10■2} CTBs and low-angle grain boundaries composed of basal 〈a60〉 dislocations created either basal-prismatic/prismatic-basal interfaces or asymmetric tilt grain boundaries, depending on whether TDs gliding away or not. Not only the emission of TDs by dislocation-TB reactions may drive TB migration, but also the resultant steps or facets along TBs can act as TD sources to facilitate TB migration. Our results indicate that roughness or severe loss of local coherency induced by dislocation-TB reactions does not intrinsically impede TB migration in Mg alloys. Dislocation-TB reactions may provide another feasible strategy to improve the ductility of Mg alloys, in addition to other techniques like grain refinement and texture modification.
Huhu Su1，Xinzhe Zhou1，Shijian Zheng2，Hengqiang Ye1,3，Zhiqing Yang1
1. Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, School of Materials Science and Engineering, University of Science and Technology of China2. State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology
摘 要：Reactions between basal 〈a60〉 dislocations and {10■2} coherent twin boundaries（CTBs） in a Mg alloy were studied with atomic resolution. Individual dislocation-CTB reactions produced steps with residual dislocations and multiple t winnin g dislocations（TDs） gliding away, consequently resulting in TB migration. Reactions between {10■2} CTBs and low-angle grain boundaries composed of basal 〈a60〉 dislocations created either basal-prismatic/prismatic-basal interfaces or asymmetric tilt grain boundaries, depending on whether TDs gliding away or not. Not only the emission of TDs by dislocation-TB reactions may drive TB migration, but also the resultant steps or facets along TBs can act as TD sources to facilitate TB migration. Our results indicate that roughness or severe loss of local coherency induced by dislocation-TB reactions does not intrinsically impede TB migration in Mg alloys. Dislocation-TB reactions may provide another feasible strategy to improve the ductility of Mg alloys, in addition to other techniques like grain refinement and texture modification.
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