中文摘要：

为建立塑性变形中微观组织演化与宏观响应的关系,依据定义的率扩散势导出了考虑温度影响的率形式流动应力方程,修正了Chaboche非线性各向同性硬化准则以考虑位错密度演化对硬化的贡献,以位错密度为内变量建立了位错密度演化模型,提出了一种基于微观组织演化机理的率形式本构模型。以927℃钛合金Ti-6Al-4V热单拉实验数据为基础,通过遗传算法确定了模型材料常数。将计算结果与实验数据进行比较,最大应力误差在12%以内,最大晶粒尺寸误差在4%以内,证明了模型的有效性。

英文摘要：

For establishing the relation of m icrostructure evolution and macro-performance in the plastic deformation, a rate dependent flow stress equation is derived based on the rate diffusion potential density which takes into consideration the influ- ence of temperature. The Chaboche;s nonlinear isotropic hardening criterion is modified to consider the influence of disloca- tion density on hardening. The evolution of dislocation density is modeled by using dislocation density as the internal state variable. A rate dependent constitutive model is proposed based on the mechanism of microstructure evolution. The material constants in the model are determined based on the single tension experimental data of Ti-6AI-4V by using the genetic algo- rithms. The comparison of calculation results and experimental data shows that the maximum errors of stress and grain size do not exceed 12% and 4% respectively. Thus, the validity of the model is verified.