(1. 湘潭大學(xué) 機(jī)械工程學(xué)院，湘潭 411105； 2. 湘潭大學(xué) 焊接機(jī)器人及應(yīng)用技術(shù)湖南省重點(diǎn)實(shí)驗(yàn)室，湘潭 411105； 3. 中冶建筑研究總院有限公司，北京 100088； 4. 東北大學(xué) 秦皇島分校，秦皇島 066004)
摘 要: 基于晶體塑性理論和有限元方法建立適合面心正方結(jié)構(gòu)(L10)金屬力學(xué)行為的細(xì)觀數(shù)值本構(gòu)關(guān)系模型，并利用該晶體塑性有限元(CPFEM)模型對(duì)γ-TiAl單晶室溫下的單向拉伸試驗(yàn)進(jìn)行模擬。模擬中拉伸方向分別選取[1 0](普通滑移)，[ 01](超滑移)、[11 ](孿生)及任意取向[ 01]。結(jié)果表明：拉伸變形中γ-TiAl單晶晶粒以中心為轉(zhuǎn)軸發(fā)生轉(zhuǎn)動(dòng)，且取向?qū)ζ渚Я＾D(zhuǎn)動(dòng)有顯著的影響。[1 0](普通滑移)取向的晶粒轉(zhuǎn)動(dòng)較小，其余取向的晶粒轉(zhuǎn)動(dòng)角度相對(duì)較大；[1 0]取向的晶粒，其拉伸阻力較小，進(jìn)而普通位錯(cuò)容易啟動(dòng)，且拉伸中以普通滑移系的激活為主；其他取向拉伸時(shí)，滑移系激活的阻力較大，必須以扭轉(zhuǎn)來調(diào)整取向因子從而協(xié)調(diào)變形，因而表現(xiàn)出顯著的晶粒轉(zhuǎn)動(dòng)。
關(guān)鍵字: γ-TiAl合金；晶體塑性；取向；晶粒轉(zhuǎn)動(dòng)；塑性變形；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
