考虑细观变形特征的镁合金宏观本构模型及数值模拟  

Macroscopic constitutive model of magnesium alloys considering meso-deformation characteristics and numerical simulation

作　　者：任一方 蓝永庭[2] 王帅 孙有平[1] 李启袭[2] Ren Yifang;Lan Yongting;Wang Shuai;Sun Youping;Li Qixi(School of Mechanical Engineering,Guangxi University of Science and Technology,545006,Liuzhou,China;School of Vocational and Technical Education,Guangxi University of Science and Technology,545006,Liuzhou,China)

机构地区：[1]广西科技大学机械工程学院,柳州545006 [2]广西科技大学职业技术教育学院,柳州545006

出　　处：《应用力学学报》2020年第4期1582-1589,I0014,共9页Chinese Journal of Applied Mechanics

基　　金：国家自然科学基金(11862002,11462002);广西自然科学基金(2016GXNSFAA380218);广西科技大学博士科学基金(校科博Z01)。

摘　　要：为了能有效描述镁合金宏观各向异性塑性行为,考虑了滑移、孪生、去孪生三种细观变形模式的特点,给出了相应的硬化函数;根据VonMises屈服准则,发展了一种镁合金宏观本构模型及其迭代算法。模型将变形模式的开启与晶粒取向相关联,同时针对镁合金孪生变形时引起的晶粒重新定向问题,描述了一种晶向偏转的方法。在此基础上编写了ABAQUS/UMAT材料用户子程序;利用开发的本构模型,开展了单轴拉伸、单轴压缩、单轴循环拉压加载条件下镁合金塑性行为的数值模拟,并对随机织构下的镁合金板材轧制过程进行了有限元仿真实验。模拟结果表明:单轴拉伸、单轴压缩和循环加载情形下的镁合金宏观硬化行为与实验结果基本吻合;轧制后镁合金板材表现出了应力-应变不均匀特性,多晶织构演化结果与实验结果基本一致。说明文中所提出的宏观本构模型、晶向偏转模型能够有效描述镁合金的宏观塑性行为和织构演化。In order to effectively describe the macroscopic anisotropic plastic behavior of magnesium alloys, the characteristics of mesoscopic deformation modes such as sliping, twinning and detwinning are considered and the corresponding hardening functions are given. A macroscopic constitutive model of magnesium alloys and its iterative algorithm are developed by using Von-Mises yield criterion. The model correlates the activation of deformation mode with grain orientation. At the same time, a method of lattice deflection is described to solve the problem of grain reorientation caused by twinning deformation of magnesium alloys. On this basis, the user subroutine of Abaqus/Umat material is programmed. Using the developed constitutive model, the plastic behaviors of magnesium alloy under uniaxial tensile, uniaxial compression and cyclic loading conditions are numerically simulated and the rolling process of magnesium alloy under random texture is simulated by finite element method. Results show that the simulation results of the macroscopic hardening behavior of magnesium alloy under uniaxial tensile, uniaxial compression and cyclic loading are basically consistent with the test results. The inhomogeneity of stress and strain appears in Rolled plate, and the results of polycrystalline texture evolution are basically consistent with the experimental results. It is shown that the macroscopic constitutive model and lattice orientation deflection model can effectively describe the plastic behavior and texture evolution of magnesium alloys.

关 键 词：本构模型 镁合金 织构 晶向偏转 各向异性 

分 类 号：O344[理学—固体力学]