TA7钛合金高温变形行为研究

Study on elevated temperature deformation behavior of TA7 titanium alloy

摘要:

为了分析TA7钛合金的热变形工艺参数,通过高温压缩试验对TA7钛合金的高温变形行为进行了研究。试验温度为1123~1273K,应变速率为0.001~1s_-1。此外,提出了一种修正并联本构模型用来分析应变速率、变形温度及应变对流动应力的影响。然后,基于动态模型,建立了TA7钛合金的热加工图,并通过微观组织分析对加工图的准确性进行了验证。结果表明,TA7钛合金合理的工艺参数为变形温度1223K,应变速率0.001s_-1,而其非稳态区域位于低温高应变速率区。

Abstract:

In this study, isothermal compression tests at the temperature range of 1123 - 1273K and the strain rate range of 0.001 - 1s-1 were conducted to analyze the elevated temperature deformation behavior of TA7 titanium alloy for the purpose of acquiring the optimum processing parameters. Besides, a modified parallel constitutive model was put forward to illustrate the high temperature flow stress as the function of the strain rate, the deformation temperature and the true strain. Thereafter, the processing map which was on the basis of dynamic materials model was established. Thereafter, the investigation was made from the microstructure of compressed TA7 titanium alloy specimens to validate processing map. According to the result, deformation temperature of 1223K and strain rate of 0.001s-1 were the best processing parameters for the TA7 alloy. In addition, the instability regions located at relatively lower temperature-higher strain rate region.