(1. 湘潭大学 机械工程学院，湘潭 411105； 2. 湘潭大学 焊接机器人及应用技术湖南省重点实验室，湘潭 411105； 3. 中冶建筑研究总院有限公司，北京 100088； 4. 东北大学 秦皇岛分校，秦皇岛 066004)
摘 要: 基于晶体塑性理论和有限元方法建立适合面心正方结构(L10)金属力学行为的细观数值本构关系模型，并利用该晶体塑性有限元(CPFEM)模型对γ-TiAl单晶室温下的单向拉伸试验进行模拟。模拟中拉伸方向分别选取[1 0](普通滑移)，[ 01](超滑移)、[11 ](孪生)及任意取向[ 01]。结果表明：拉伸变形中γ-TiAl单晶晶粒以中心为转轴发生转动，且取向对其晶粒转动有显著的影响。[1 0](普通滑移)取向的晶粒转动较小，其余取向的晶粒转动角度相对较大；[1 0]取向的晶粒，其拉伸阻力较小，进而普通位错容易启动，且拉伸中以普通滑移系的激活为主；其他取向拉伸时，滑移系激活的阻力较大，必须以扭转来调整取向因子从而协调变形，因而表现出显著的晶粒转动。
关键字: γ-TiAl合金；晶体塑性；取向；晶粒转动；塑性变形；有限元
（1.School of Mechanical Engineering, Xiangtan University, Xiangtan 411105, China; 2. Key Laboratory of Welding Robot and Application Technology of Hunan Province, Xiangtan University, Xiangtan 411105, China; 3. Building and Construct Research Institute Co. Ltd. of MCC, Beijing 100088, China; 4. Northeastern University at Qinhuangdao, Qinhuangdao 066004, China）
Abstract:A meso-scale numerical constitutive model was established by the theory of crystal plasticity and finite element method to describe the mechanical behavior of the face-centered tetragonal (L10) metal. Based on this model, uniaxial tension of γ-TiAl single crystal at room temperature was simulated. The tensile orientation was ordinary slip orientation [1 0], super slip orientation [ 01], twin slip orientation [11 ] and arbitrary orientation [ 01], respectively. The results show that the single crystals rotate along the central axis during the tensile deformation. Moreover, orientation has dramatic effect on the grain rotation. The single crystal with tensile orientation of [1 0] (ordinary slip) has less rotation angle. However, the others have larger rotation angle. With tension along the orientation of [1 0] (ordinary slip), less tensile resistance leads to easy activation of slipping of the ordinary dislocation. Furthermore, the activation of ordinary slip system is primary during the tensile process. With tension along the other orientations, the crystals should adjust the orientation factor to accommodating the deformation by grain torsion, which shows larger rotation angle.
Key words: γ-TiAl alloy; crystal plastic; orientation; grain rotation; plastic deformation; finite element
