短时高温钛合金热变形行为研究

Research on hot deformation behaviors of short-time high temperature titanium alloy

采用热模拟试验机对铸态Ti-6Al-4Sn-8Zr-0.8Mo-1.5Nb-1W-0.25Si短时高温钛合金进行热模拟试验,研究了其高温变形行为。试验结果表明:该高温钛合金热变形对温度和变形速率敏感,随着应变速率降低和变形温度升高,真应力显著降低。利用高温压缩应力应变数据绘制了热加工图,分析结果显示:(α+β)相区的900~960℃、0.035~0.368 s^(-1)和960~1 010℃、0.165~0.577 s^(-1);β相区的1 010~1 020℃、0.165~1 s^(-1)为最适合加工的区域。经计算,(α+β)两相区的热变形激活能为316.229 kJ/mol,并构建了该相区内的本构方程。

The thermal simulation test was carried out and high temperature deformation behavior of the as-cast Ti-6Al-4Sn-8Zr-0.8Mo-1.5Nb-1W-0.25Si short-time high temperature titanium alloy was studied. The experimental results show that the deformation of Ti-6Al-4Sn-8Zr-0.8Mo-1.5Nb-1W-0.25Si alloy is sensitive to the deformation temperature and deformation rate, and the true stress decreases significantly with the decrease of strain rate and the increase of deformation temperature. The hot working diagram was plotted using the high temperature compression stress-strain data. The analysis results demonstrate that 900-960 ℃, 0.035-0.368 s^(-1)and 960-1 010 ℃, 0.165-0.577 s^(-1)in the(α+β) phase region as well as 1 010-1 020 ℃, 0.165-1 s^(-1)of β phase region are the most suitable regions for hot processing. The thermal deformation activation energy of(α+β) two-phase region is calculated to be316.229 kJ/mol, and the constitutive equation of the region is established as well.