TNTZ钛合金流变行为及物理基本构模型

借助Gleeble-3500热模拟机对Ti-29Nb-13Ta-4.5Zr(TNTZ)钛合金进行了变形温度为700~900 ℃、应变速率为0.001~1 s-1的等温恒应变速率压缩实验，分析了应变速率和变形温度对TNTZ钛合金流变应力的影响。根据实验数据，计算了不同变形条件下的温升值，分析了变形热产生的规律。综合考虑温度对材料自扩散系数和弹性模量的影响以及应变对合金流变应力的影响，通过多元线性回归拟合材料参数与应变之间的函数关系，构建了基于应变补偿的物理基本构模型。研究结果表明：TNTZ钛合金的流变应力随应变速率的增大而增大，随变形温度的升高而减小；变形热效应引起的温升与应变速率正相关，与变形温度负相关。通过应变补偿建立的物理基本构模型预测精度较高，模型相关系数R达0.964，平均相对误差为10.63%。

Rheological Behavior and Physically-based Constitutive Model of TNTZ Titanium Alloy#br#

The isothermal constant strain rate compression experiments of Ti-29Nb-13Ta-4.5Zr(TNTZ) titanium alloy in the range of deformation temperature 700~900 ℃ and strain rate 0.001~1 s-1 were carried out with Gleeble-3500 thermal simulator. The effects of strain rate and deformation temperature on the rheological stress of TNTZ titanium alloy were analyzed. According to the experimental data, the temperature rise values under different deformation conditions were calculated, and the law of deformation heat generation was analyzed. Comprehensively considering the influences of temperature on material self-diffusion coefficient and elastic modulus and the effects of strain on alloy rheological stress, a physically-based constitutive model was constructed based on strain compensation, and by multiple linear regression the functional relationship among material parameters and strain was fitted. The results show that the rheological stress of TNTZ titanium alloy increases with the increase of strain rate and decreases with the increase of deformation temperature. The temperature rise caused by deformation heat effect is positively correlated with strain rate and negatively correlated with deformation temperature. The physically-based constitutive model established by strain compensation has high prediction accuracy. The correlation coefficient R of the model reaches 0.964, and the average relative error is as 10.63%.