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考虑金属材料晶体细观塑性变形流动的各向异性性质以及晶体滑移的非线性运动硬化,以Voronoi多晶集合体作为材料的代表性单元(RVE),用晶体塑性模型描述金属材料的细观本构关系,对多晶纯Cu进行了晶粒尺度的对称应变循环细观分析.证实了本文模型和方法可以用于描述多晶金属材料不同应变幅的循环滞回特性,并可以用于估计金属材料在循环加载过程中后继屈服面形状和曲率与预加载方向相关的变化.分析发现:在对称应变循环中,随循环数增加,多晶材料宏观拉伸方向的内部细观应变分量的统计变异系数(COV)不断增加,材料内部晶格的不均匀细观转动也越来越显著.这些结果表明,循环过程中应变分布差异和晶格转动差异逐渐增大,从而导致材料内部微结构越来越不均匀.
Considering the anisotropic property of metal mesoscopic plastic deformation flow and the nonlinear kinematic hardening of crystal slip, the Voronoi polycrystal aggregate is taken as the representative unit (RVE) of the material, and the crystal plasticity model is used to describe the microscopic view of the metal material Constitutive relationship, the microscopic analysis of the grain-scale symmetrical strain of the pure polycrystalline Cu has been carried out. The results show that the model and the method can be used to describe the cyclic hysteresis characteristics of different strain amplitude of the polycrystalline metallic material and can be used to estimate The change of the shape and curvature of the subsequent yield surface and the preloading direction of the metal material during cyclic loading are analyzed.The results show that with the increase of the number of cycles in the symmetrical strain cycle, the statistics of the internal meso-strain components in the macroscopic stretching direction of the polycrystalline material The coefficient of variation (COV) increases continuously, and the non-uniform mesoscopic rotation of the crystal lattice in the material becomes more and more significant.These results show that the difference of strain distribution and the difference of lattice rotation increase gradually during cycling, The more uneven.