镁单晶塑性变形行为的晶体塑性耦合孪晶相场模拟  

Plastic deformation of magnesium single crystal:a crystal plasticity coupled twinning phase field simulation

作　　者：胡佳晨 徐波 于超 康国政 Jiachen Hu;Bo Xu;Chao Yu;Guozheng Kang(Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province,School of Mechanics and Aerospace Engineering,Southwest Jiaotong University,Chengdu,611756,China;Failure Mechanics and Engineering Disaster Prevention,Key Laboratory of Sichuan Province,Sichuan University,Chengdu,610065,China;Institute of Applied Mechanics,State Key Laboratory of Traction Power,Southwest Jiaotong University,Chengdu,610031,China)

机构地区：[1]Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province,School of Mechanics and Aerospace Engineering,Southwest Jiaotong University,Chengdu,611756,China [2]Failure Mechanics and Engineering Disaster Prevention,Key Laboratory of Sichuan Province,Sichuan University,Chengdu,610065,China [3]Institute of Applied Mechanics,State Key Laboratory of Traction Power,Southwest Jiaotong University,Chengdu,610031,China

出　　处：《Acta Mechanica Sinica》2024年第3期123-144,共22页力学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos.12192210 and 12192214);the independent project of State Key Laboratory of Traction Power (Grant No.2022TPL-T05).

摘　　要：本文建立了一个晶体塑性-孪晶相场耦合模型来研究镁单晶的塑性变形行为.在晶体塑性模型中考虑了三种典型的滑移模式,即基面滑移、柱面滑移、锥面滑移,而在孪晶相场模型中考虑了化学能、梯度能和弹性能的作用.模拟结果表明:在沿孪生方向剪切加载诱导孪晶的过程中,不同阶段的应力水平和不同方向孪晶界面的迁移率存在较大差异.孪晶在早期呈透镜状,而在侧向长大阶段呈平板状,并且孪晶出现后有基面滑移被激活;非基面滑移在基体完全转变为孪晶后被激活.在一个拉-压载荷周期内,不同取向的镁单晶中出现不同的塑性变形模式,当加载方向平行于c轴时,对应的变形模式为孪生-解孪-锥面滑移-复孪生;当加载方向垂直于c轴时,对应的变形模式为柱面滑移-柱面滑移孪生-孪生-解孪,这两种单晶均表现出强拉压不对称性;当加载方向与c轴夹角为45°时,仅发生基面滑移,不存在拉压不对称现象.A crystal plasticity coupled twinning phase field(CP-TPF)model was developed to investigate the plastic deformation of magnesium(Mg)single crystal.Three types of slip systems,i.e.,basal,prismatic,and pyramidal slip ones were considered in the crystal plasticity model,while the crystalline,gradient,and elastic energies were considered in the phase field model for twinning.The results show that during the twinning induced by the shear loading along the twinning direction,the stress levels at different stages and the mobility of twin interfaces in different directions show huge differences.The twins are lenticular at the early stage and show a flat plane during the growth,and the activation of basal slip follows the twinning deformation.Non-basal slip is activated after the matrix is completely transformed into the twins.Different plastic deformation modes are observed in Mg single crystal with different crystalline orientations during one tensile-compressive loading cycle:The corresponding deformation modes are twinning-detwinning-pyramidal slip-retwinning when the loading direction is parallel to the c axis and are prismatic slip-twinning&prismatic slip-twinning-detwinning when the loading direction is perpendicular to the c axis of the single crystal,a strong tension-compression asymmetry is shown in both the two simulations;while only the basal slip occurs,and no tension-compression asymmetry is observed when the angle between the loading direction and the c axis is 45°.

关 键 词：Magnesium single crystal Phase field model TWINNING Dislocation slipping Crystalline orientation 

分 类 号：TG142[一般工业技术—材料科学与工程]