Crystal Plasticity Finite Element Study of Incompatible Deformation Behavior in Two Phase Microstructure in Near β Titanium Alloy

摘要:

基于晶体塑性模型，研究了近 β 钛合金中(α + β) 两相组织的不协调变形行为。首先，双晶体模型的计算结果表明 (α + β) 两相组织中的塑性变形是不协调的，而且α 相的变形行为与晶体取向和加载方向密切相关。另外，通过耦合三维 Voronoi几何模型，探讨了近 β钛合金中球状初生 α 相对宏观力学响应的影响。利用该 CPFE-VT 数值模型，研究发现 α 相与 β 相的不协调变形导致了合金强度随 α 相体积分数的增加而成线性降低。此外，β 基体中 α 相的分布对合金应力-应变响应也有较大的影响。针对具有两相组织的近 β 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性能预测提供了重要的途径。

Abstract:

The incompatibility of plastic deformation in a near β titanium alloy with (α + β) two phases microstructure was analyzed based on the crystal plasticity finite element (CPFE) model. The bicrystal simulation results show that the plastic deformation in the (α + β) two phases microstructure is incompatible, and the deformation behavior of α phase is significantly affected by the crystal orientation and loading direction. In addition, through coupling with three-dimensional (3D) Voronoi tessellation (VT) geometric model, the effect of globular primary α phase in the β matrix on the macroscopic mechanical response was discussed. Based on the CPFE-VT model, it is found that the incompatibility of plastic deformation between the α and β phases can result in a linear reduction of the macroscopic strength with the increase of the volume fraction of α phase. Furthermore, the distribution of primary α phase also plays an important role in the stress-strain response. The proposed model for near β titanium alloy can yield important informations for the microstructure controlling and the performance prediction.