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基于率相关晶体塑性理论,以滑移作为主要的变形机制,建立了描述多晶钛合金室温拉伸变形行为的本构模型。并采用三维Voronoi几何模型仿真初始组织创建了多晶集合体。利用该数值模型,探讨了多晶集合体特征对合金宏观力学响应的影响。研究结果表明,多晶集合体三边的尺寸差异将导致集合体的应力应变关系沿3个方向出现各向异性,同时在长度方向上易发生颈缩现象。此外,多晶集合体中的晶粒形貌与取向分布对合金的宏观应力应变响应也有重要的影响。针对单相钛合金建立的晶体塑性有限元模型为钛合金组织控制技术的发展以及加工工艺的优化提供了重要的技术途径。
Based on the rate-dependent crystal plasticity theory and slip as the main deformation mechanism, a constitutive model describing the tensile deformation behavior of polycrystalline titanium alloys at room temperature was established. A polyhedral aggregate was created by simulating the initial tissue with a 3D Voronoi geometry model. Using this numerical model, the effect of polycrystalline aggregates on the macroscopic mechanical response of the alloy was discussed. The results show that the size difference of three sides of polycrystalline aggregates will lead to anisotropy along the three directions of the stress-strain relationship of the aggregates, and the necking phenomenon tends to occur in the longitudinal direction. In addition, the grain morphology and orientation distribution in the polycrystalline aggregate also have an important effect on the macroscopic stress-strain response of the alloy. The crystal plastic finite element model established for single-phase titanium alloy provides an important technical approach for the development of titanium alloy tissue control technology and the optimization of processing technology.