单相钛合金晶体塑性有限元研究:多晶集合体特征对力学响应的影响(英文)

Crystal Plasticity Finite Element Simulations for Single Phase Titanium Alloys: Effect of Polycrystalline Aggregate Features on the Mechanical Response

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。

Within the rate-independent crystal plasticity framework, a constitutive model was constructed to describe the uniaxial tension of polycrystalline titanium alloy at ambient temperature by considering crystallographic slip as the main deformation mechanism. The three-dimensional（3D） Voronoi tessellation（VT） geometric model was used to create the polycrystalline aggregates for initial microstructure. Based on the model, the effects of polycrystalline aggregate features on the macroscopic mechanical responses were discussed. Results show that the size differences of the three directions in polycrystalline aggregates will lead to the anisotropies of the stress-strain responses in the three directions, wherein the necking phenomenon appears in the long length direction. Besides, it is found that the grain morphology and orientation have significant influences on stress-strain responses as well. The proposed model for single phase titanium alloy provides important informations for the microstructure controlling and the optimization of process parameters.