Ti-6Al-4V钛合金组成相微观变形行为影响因素

Influencing Factors of Micro Deformation Behavior of Constituent Phases in Ti-6Al-4V Titanium Alloy

摘要:

本文基本真实组织图像建立了Ti-6Al-4V合金的微观力学有限元模型,考虑合金双相特征研究了室温单轴拉伸时的微观变形行为。结果表明：外部加载力主要由较硬的β转变组织承担,而塑性变形主要由较软的初生α相承担,即便在相同相内部,不同位置的应力和应变也存在差异。随宏观应变增大,初生α相与β转变组织的应变比、β转变组织与初生α相的应力比首先基本保持不变,而后迅速增大,最后保持稳定。初生α相的体积分数和晶粒尺寸对组成相内部的应变和应力分布有显著影响,随体积分数增大或晶粒尺寸减小,应变比和应力比分别增大和减小。

Abstract:

In this paper, A micro-mechanics finite element model is established based on the realistic microstructure of Ti-6Al-4V alloy. And considering the dual-phase characteristic, the micro deformation behaviors during the uniaxial tension at ambient temperature are studied. The results show that the hard transformed β matrix (β_t) in Ti-6Al-4V alloy bears most external loading force, while the external load deformation is mainly carried out by the soft primary α phase (α_p). The strain and stress distribution in different regions within the same phase are also strongly asymmetrical. With the increase of the macro-strain, the strain ratio of α_p to β_t and the stress ratio of β_t to α_p are basically unchanged at first, then increase rapidly, and finally maintain stability. The volume fraction and grain size of α_p have a significant effect on the strain and stress distribution in the constituent phases. With the increases of volume fraction or the decreases of grain size, the strain ratio and the stress ratio increases and decreases, respectively.