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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。
In order to establish the relationship between microstructure evolution and macroscopic response in plastic deformation, a rate-form flow stress equation considering the influence of temperature is derived according to the defined rate diffusion. The Chaboche nonlinear isotropic hardening criterion is modified to consider the effect of dislocation density evolution on hardening , The dislocation density evolution model was established with the dislocation density as the internal variable and a rate formal constitutive model based on microstructure evolution was proposed. Based on the experimental data of Ti-6Al-4V hot single-pull test of 927 ℃ titanium alloy, the model material constants were determined by genetic algorithm. The calculated results are compared with the experimental data. The maximum stress error is within 12% and the maximum grain size error is within 4%, which proves the validity of the model.