Modes of grain growth and mechanism of dislocation reaction under applied biaxial strain:Atomistic and continuum modeling

作     者：Ying-Jun Gao Qian-Qian Deng Zhe-yuan Liu Zong-Ji Huang Yi-Xuan Li Zhi-Rong Luo Ying-Jun Gao;Qian-Qian Deng;Zhe-yuan Liu;Zong-Ji Huang;Yi-Xuan Li;Zhi-Rong Luo

作者机构：Guangxi Advanced Key Laboratory of Novel Energy MaterialsGuangxi Key Laboratory for the Relativistic AstrophysicsSchool of Physics Science and EngineeringGuangxi UniversityNanning530004China Institute of Physics Science and Engineering TechnologyYulin Normal UniversityYulin537000China 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2020年第47卷第14期

页      面：236-250页

核心收录：

学科分类：08[工学] 0817[工学-化学工程与技术] 0806[工学-冶金工程] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0703[理学-化学] 0802[工学-机械工程] 0801[工学-力学（可授工学、理学学位）] 0702[理学-物理学] 

基　　金：supported by National Nature Science Foundation of China(Nos.51161003 and 51561031) Nature Science Foundation of Guangxi Province(No.2018GXNSFAA138150)。 

主　　题：Grain boundary splitting Grain growth Dislocation reaction Atomistic simulation Continuum modeling 

摘      要：The phase field crystal method and Continuum Modeling are applied to study the cooperative dislocation motion of the grain boundary(GB)migration,the manner of the nucleation of the grain and of the grain growth in two dimensions(2 D)under the deviatoric deformation at high temperature.Three types of the nucleation modes of new finding are observed by the phase field crystal simulation:The first mode of the nucleation is generated by the GB splitting into two sub-GBs;the second mode is of the reaction of the sub-GB dislocations,such as,the generation and annihilation of a pair of partial Frank sessile dislocation in 2 D.The process can be considered as the nucleation of dynamic recrystallization;the third mode is caused by two oncoming rows of the dislocations of these sub-GBs,crossing and passing each other to form new gap which is the nucleation place of the new deformed grain.The research is shown that due to the nucleation of different modes the mechanism of the grain growth by means of the sub-GB migration is different,and therefore,the grain growth rates are also different.Under the deviatoric deformation of the applied biaxial strain,the grain growth is faster than that of the grain growth without external applied stress.It is observed that the cooperative dislocation motion of the GB migration under the deviatoric deformation accompanies with local plastic flow and the state of the stress of the system changes sharply.When the system is in the process of recrystallized grain growth,the system energy is in an unstable state due to the release of the strain energy to cause that the reverse movement of the plastic flow occurs.The area growth of the deformed grain is approximately proportional to the strain square and also to the time square.The rule of the time square of the deformed grain growth can also be deduced by establishing the continuum dynamic equation of the biaxial strain-driven migration of the GB.The copper metal is taken as an example of the calculation,and the obtained result is a good agreement with that of the experiment.