GB_009Cu-Ag层状复合板在冷轧过程中的剪切带行为模拟-贾楠.doc

Cu-Ag层状复合板在冷轧过程中的剪切带行为模拟 贾楠1，刘肖朦1，赵骧1 (1. 东北大学材料科学与工程学院、材料系，辽宁 沈阳 邮编；110819) 摘要：本文借助 X 射线衍射宏观织构测试并结合使用先进的晶体塑性有限元模型对由不同层错能面心立方金属（铜和银）组成的层状复合板在冷轧过程中的织构分布和剪切带行为进行了研究。XRD织构测试结果表明，对中等层错能的铜金属层而言，其轧制织构在不同厚度上表现出明显的非均匀分布。借助包含有位错、孪晶、剪切带形变机制的晶体塑性有限元模型对不同初始取向组合的铜-银双晶冷轧变形的模拟表明：剪切带系统的开动具有显著的取向依赖性，即Copper织构为易于剪切带开动的取向，而Goss取向不利于剪切带开动；剪切带可以由优先开动的一相穿过异质界面向另一相传递。当初始织构为Copper取向时，低层错能的银较中等层错能铜易于产生剪切带。当存在异质界面时，两相金属之间存在明显的相互剪切作用，使界面处的晶粒发生较大取向转动。 关键词：面心立方金属；复合材料；塑性变形；剪切带；晶体塑性模型 Abstract: The inhomogeneous texture distribution in a lamellar composite incorporating two dissimilar face-center-cubic metals, i.e., Cu and Ag, under cold rolling is investigated by using X-ray diffraction and crystal plasticity finite element model (CPFEM). When the thickness reduction is high, the heterogeneity of textures is found in the Cu layer. Namely, in the region adjacent to the rollers the Copper component dominates over the other textures, whereas in the region closed to the heterointerface the Brass component is the dominant texture. Lattice rotations within the heterophase microstructure are then addressed by crystal plasticity finite element （CPFE） modeling that considers not only crystallographic dislocation slip and twinning but also non-crystallographic shear banding micromechanisms. The simulations show that the hetero-interface between the Cu and Ag layers plays an important role in texture development of the Cu layer when the two metals are co-deformed. In the Cu phase of the studied composite, significant shear banding is triggered by stress concentration at the hetero-interface compared to the positions away from the interface, which leads to the significant texture evolution in the interface region. Key words: fcc metal; composite material; plastic deformation; shear band; crystal plasticity model 1引言 多晶金属材料的宏观力学性能主要依赖于其内部的微结构特征，尤其是塑性流动过程中的形变系统开动以及晶粒初始取向。其中，普遍存在于形变金属中的织构现象，对材料的力学行为具有重要影响，直接关系其在生产制备及工程应用中的性能。因此，对材料的微观形变机制准确理解并预测和控制形变织构，已成为研究和开发新材料领域的重要发展方向。由异种金属以较细尺度（微米、亚微米甚至纳米）单元层厚度交替叠加组成的金属