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针对近β钛合金提出了一种以位错密度变化率作为内变量的热变形本构模型,该模型同时考虑了溶质元素的固溶强化作用和位错之间的交互作用对流变应力的影响。将该模型应用于一种新型近β钛合金Ti-7Mo-3Al-3Nb-3Cr(Ti-7333),并采用基于目标优化的遗传算法定量确定了Ti-7333合金的本构模型参数。模型计算的结果表明,利用该热变形本构模型计算出的流变应力与实验数据间的平均相对误差为7.2%,采用基于位错密度变化率的近β钛合金本构模型能够有效地表征Ti-7333合金的流变行为。
A near-β titanium alloy is proposed as a thermal deformation constitutive model based on the rate of dislocation density change as an internal variable. The model also considers the influence of the solid solution strengthening effect of solute elements and the interaction between dislocations on the flow stress . The model was applied to Ti-7Mo-3Al-3Nb-3Cr (Ti-7333), a new type of near-beta titanium alloy. The constitutive model parameters of Ti-7333 alloy were quantitatively determined by genetic algorithm based on objective optimization. The results of the model calculation show that the average relative error between the calculated flow stress and the experimental data is 7.2%. The near-β titanium alloy constitutive model based on the rate of change of dislocation density can effectively characterize Rheological Behavior of Ti-7333 Alloy.