Transactions of Nonferrous Metals Society of China The Chinese Journal of Nonferrous Metals

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中国有色金属学报

ZHONGGUO YOUSEJINSHU XUEBAO

第29卷    第8期    总第245期    2019年8月

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文章编号:1004-0609(2019)-08-1660-16
基于滑移与孪生镁合金晶体塑性本构模型及微结构关联分析
蓝永庭1,陈 渊3,任一方2,张克实4,王 帅2

(1. 广西科技大学 职业技术教育学院,柳州 545006;
2. 广西科技大学 机械工程学院,柳州 545006;
3. 广西大学 机械工程学院,南宁 530004;
4. 广西大学 土木建筑工程学院,南宁 530004
)

摘 要: 为了揭示镁合金晶体微结构与孪生变形之间的关联性,采用伪滑移模式描述孪生变形,建立包含滑移与孪生变形机制的晶体塑性本构关系,推导以剪切应变率作为自变量的本构方程牛顿-拉普森迭代式。采用基于体素方法建立的多晶三维微结构有限元模型,对挤压镁合金材料沿挤压方向加载的单轴拉伸和压缩变形行为进行模拟。模拟结果表明,单轴加载下模拟与试验的材料宏观硬化行为基本吻合,及压缩变形的模拟织构演化与试验织构演化也基本趋同。对多晶体内基本物理量的统计分析表明,该模型能够展现多晶内的应力应变、孪晶体分数在空间的不均匀分布特性,而孪晶体分数分布与晶粒尺寸、晶界位向角及晶界倾角等微结构之间缺乏确切的关联性,表明非均匀微结构所导致的独特应力非均匀状态并不是出现孪生变形与微结构强关联性的原因。

 

关键字: 镁合金;孪生变形;微结构;塑性本构模型;织构

Constitutive model based on slip and twinning of AZ31 Mg alloy and analysis of microstructural relatedness
LAN Yong-ting1, CHEN Yuan3, REN Yi-fang2, ZHANG Ke-shi4, WANG Shuai2

1. School of Vocational and Technical Education, Guangxi University of Science and Technology, Liuzhou 545006, China;
2. School of Mechanical Engineering, Guangxi University of Science and Technology, Liuzhou 545006, China;
3. School of Mechanical Engineering, Guangxi University, Nanning 530004, China;
4. College of Civil Engineering and Architecture, Guangxi University, Nanning 530004, China

Abstract:In order to discover the relationship between the twinning deformation and microstructure in Mg alloy, describing twinning by pseudo-slip mode, the crystal plastic constitutive relation including slipping and twinning was established. And the Newton-Raphson iteration method was developed with the shear strain rate directly as the basic variables of iteration. The deformation behaviors of extruded Mg alloy loaded by uniaxial tension and compression along the extrusion direction were simulated using the finite element model of polycrystal based on voxel algorithm. The simulation results show that the macroscopic hardening behaviors predicted using the proposed model are in good agreement with the experimental results, and there are the same evolutions of polycrystalline texture during testing and simulating for Mg alloy. The statistical analyses of principal physical variables show that the proposed constitutive model is available to demonstrate the inhomogeneous characteristic of spatial distribution of stress-strain, the fraction of twinning in polycrystal, but there is a short age of the explicit relatedness of the volume fraction of twinning with respect to grain size, the misorientation between grain boundary plane normal and loading direction, the grain boundary misorientation angles in polycrystal, respectively. It is shown that the inhomogeneous state of unique stress resulted from the inhomogeneity of microstructure is not the reason for the strong relatedness between twinning deformation and microstructure.

 

Key words: magnesium alloy; twinning deformation; microstructure; plastic constitutive model; texture

ISSN 1004-0609
CN 43-1238/TG
CODEN: ZYJXFK

ISSN 1003-6326
CN 43-1239/TG
CODEN: TNMCEW

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