Ti-48Al-2Nb-2Cr合金热变形行为及本构关系研究

采用Gleeble-1500热力模拟机对铸态Ti-48Al-2Nb-2Cr合金进行高温变形热压缩试验,变形温度范围为1050~1200℃,应变速率范围为0.001~0.1s^-1,压缩变形量为60%。研究该合金高温变形温度和应变速率与流变应力之间的关系,计算了合金激活能,并建立了Ti-48Al-2Nb-2Cr合金的Arrhenius本构模型和多元线性回归的本构模型。结果表明,该合金的激活能随温度升高和应变速率增大而增大;Arrhenius本构模型的相关系数为0.98228,平均相对误差为9.97%,相对误差在10%以内的点只占62.0%;而采用多元线性回归本构模型的相关系数为0.99566,平均相对误差为4.76%,相对误差在10%以内的点占92.6%,本构精度较高。

Thermal Deformation Behavior and Constitutive Relation of Ti-48Al-2Nb-2Cr Alloy

The as-cast Ti-48Al-2Nb-2Cr alloy was subjected to high temperature hot compressive deformation test by using Gleeble-1500 thermal simulator at 1050℃to 1200℃and the strain rate of 0.001 s^-1 to 0.1 s^-1 as well as deformation rate of 60%.The relationship between deformation temperature,strain rate and flow stress during high temperature deformation of the alloy was analyzed.Meanwhile,the active energy of the alloy was calculated.The Arrhenius constitutive model of Ti-48Al-2Nb-2Cr alloy and the constitutive model of multiple linear regression were established.The results reveal that the active energy of the alloy is increased with increasing in temperature and strain rate.The correlation coefficient Rof the Arrhenius constitutive model reaches 0.98228,and the average relative error is 9.97%.In addition,the relative error within 10%only accounts for 62.0%.The correlation coefficient Rof the constitutive model of Ti-48Al-2Nb-2Cr alloy with multivariate linear regression reaches0.99566,and the average relative error is 4.76%,meanwhile,the relative error within 10%is 92.6%,presenting a higher constitutive accuracy.