应变诱发四方相小角度对称倾侧晶界位错反应的晶体相场模拟  

Phase field crystal simulation of strain-induced square phase low-angle symmetric tilt grain boundary dislocation reaction

作　　者：夏文强 赵彦 刘振智 鲁晓刚 Xia Wen-Qiang;Zhao Yan;Liu Zhen-Zhi;Lu Xiao-Gang(State Key Laboratory of Advanced Special Steel,School of Materials Science and Engineering,Shanghai University,Shanghai 200444,China)

机构地区：[1]上海大学材料科学与工程学院,省部共建高品质特殊钢冶金与制备国家重点实验室,上海200444

出　　处：《物理学报》2022年第9期234-244,共11页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:51771226)资助的课题。

摘　　要：采用晶体相场法研究了外加应变作用下,不同取向差的四方相对称倾侧小角度晶界的位错运动与反应及反应过程中的位错组态,通过采用几何相位法对位错周围应变场进行了表征.结果表明,凝固弛豫达到稳态后,晶界两侧位错平行且方向相反,随晶界两侧晶粒取向差增大,位错数目增加,距离减小,且体系自由能增加.在外加应变作用下,晶界位错经历攀移、发射、反应湮灭等阶段,体系自由能呈现波动.当取向差增大时,位错运动方式由攀移向攀滑移转变,产生更多类型的位错组构型,并发生相应的位错与位错组之间的反应.对于不同构型的位错反应,正切应变驱动位错靠近,负切应变驱动位错湮灭.In this paper,the phase field crystal method is used to study the dislocation motion and reaction of the square phase symmetric tilt low-angle grain boundaries,and the dislocation configurations with different misorientation angles are analyzed under the action of applied strain.The geometric phase approach is used to characterize the strain field around the dislocations.The results show that after the solidification relaxation,the inter facial dislocations on both sides of the grain are distributed in parallel but opposite direction.With the increase of misorientation angle between grains,the number of dislocations increases,the spacing between them decreases,and the free energy of the system increases.Imposed by the applied strain,the grain boundary dislocations undergo climbing,launching,and reactive annihilation,with the free energy fluctuating.When the misorientation increases,the dislocation motion mode changes from climbing to climbing-sliping,resulting in more dislocation group configurations,and more reactions between dislocations and dislocation groups.For the dislocation reactions of different configurations,positive shear strain drives dislocations to approach,and negative shear strain drives dislocations to annihilate.

关 键 词：晶体相场 四方相 位错反应 晶界 

分 类 号：O772[理学—晶体学]