耦合孪生的TWIP钢多晶体塑性变形行为研究  

INVESTIGATION OF PLASTIC DEFORMATION BEHAVIOR ON COUPLING TWINNING OF POLYCRYSTAL TWIP STEEL

作　　者：孙朝阳[1] 郭祥如 郭宁[1] 杨竞[1] 黄杰[1,2] 

机构地区：[1]北京科技大学机械工程学院,北京100083 [2]宝山钢铁股份有限公司,上海201900

出　　处：《金属学报》2015年第12期1507-1515,共9页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目51105029和51575039;国家自然科学基金委员会与中国工程物理研究院联合基金项目U1330121;非线性力学国家重点实验室开放基金项目LNM201512资助~~

摘　　要：基于已建立的单晶体塑性模型,建立了耦合孪生的孪生诱发塑性(TWIP)钢多晶体塑性模型,该模型采用有限元多晶均匀化处理相邻晶粒间的几何协调和应力平衡条件,获得了单晶体与多晶体状态变量的关系,开发了基于ABAQUS/UMAT的计算程序.采用EBSD研究了TWIP钢拉伸应变分别为0.27和0.6时的织构变化,并对模型进行了应力应变及织构演化的验证.用该本构模型分别建立了拉伸、压缩和扭转3种简单加载条件下的有限元模型,分析了不同变形条件下的宏观力学响应及织构演化规律.结果表明:拉伸变形过程中,应变硬化现象和织构密度水平随应变增加而增强;在压缩过程中,织构类型随应变增加而发生变化,但是织构密度水平基本不变;而在扭转过程中,当扭转应变较小时,基本无织构形成,随着应变增加,织构逐渐显现出来,这是因为变形较小时,圆柱沿径向方向内部变形量较小,故织构不明显.Twinning induced plasticity （TWIP） steel exhibits high strength and exceptional plasticity due to the formation of extensive twin under mechanical load and its ultimate tensile strength and elongation to failure ductility-value can be as high as 5×10^4 MPa·%, which provide a new choice for automobile in developing the light-weight and improving safety. Generally, due to the texture was formed during process of plastic deformation, metal material appear anisotropic behavior. The deformation mechanisms, responsible for this high strain hardening, are related to the strain-induced microstructural changes, which was dominated by slip and twinning. Different deformation mechanisms, which can be activated at different stages of deformation, will strongly influence the stress strain response and the evolution of the microstructure. In this work, to predict the texture evolution under different loading conditions and understand these two deformation mechanisms of plastic deformation process, a polycrystal plasticity constitutive model of TWIP steel coupling slip and twinning was developed based on the crystal plasticity theory and single crystal plasticity constitutive model. A polycrystal homogenization method to keep geometry coordination and stress balance adjacent grains was used, which connected the state variables of single crystal and polycrystal. And then the model was implemented and programed based on the ABAQUS/UMAT platform. The texture evolution was obtained by EBSD at strain 0.27 and 0.60, respectively. The finite element models of tensile, compression and torsion processes were built by using the constitutive model. The mechanical response and texture evolution during plastic deformation process of TWIP steel were analyzed. The results show that with the increasing of the strain, the strain hardening phenomenon and texture density enhanced during the tensile process. Although texture types changed, texture density unchanged during the compression process. Owing to deformation increasing along the dia

关 键 词：TWIP钢 晶体塑性 多晶均匀化 织构预测 塑性变形 

分 类 号：TG142.1[一般工业技术—材料科学与工程]