铸态TC17钛合金流动应力预测

Flow Stress Prediction for As-cast TC17 Titanium Alloy

通过热模拟压缩试验对铸态TC17钛合金的高温变形行为进行了研究。温度范围1073~1373 K,应变速率范围0.01~20 s^-1。建立了4种本构模型,分别是应变补偿双曲正弦模型、修正Arrhenius模型、Johnson Cook模型和修正Johnson Cook模型,用来表征铸态TC17钛合金的高温流动应力。采用相关系数、平均相对误差和相对误差统计分析了4种模型的准确性。结果表明:JohnsonCook模型不能用来描述铸态TC17钛合金高温流动应力;在α+β两相区,应变补偿双曲正弦模型精度最高,而在β单相区修正Johnson Cook模型更为准确;在整个变形温度范围内,应变补偿双曲正弦模型比其他几种模型的准确性更高。

The hot deformation behavior of as-cast TC17 titanium alloy was investigated by isothermal hot compression tests at temperatures of 1073~1373 K and strain rates of 0.01~20 s^-1.The four constitutive models,strain compensated Arrhenius-type(SCA),modified Arrhenius-type(MA),Johnson Cook(JC)and modified Johnson Cook(MJC),were used to represent the elevated temperature flow behavior of as-cast TC17 titanium alloy.The suitability levels of these models were evaluated by comparing the correlation coefficient R,average absolute relative error(AARE),and relative error.The results indicate that the JC model is inadequate to predict the flow stress of as-cast TC17 titanium alloy;the SCA model has the highest accuracy to descript of flow behavior of TC17 alloy in theα+βtwo-phase region in the studied range.While the MJC model exhibits the highest accuracy in theβsingle-phase region.Within the whole deformation temperature range,the SCA model proposed in this paper can more accurately conform to the high-temperature rheological curve of as-cast TC17 titanium alloy.