(中国科学院 金属研究所，沈阳 110016)
摘 要: 采用Gleeble® 3800热模拟机研究粉末冶金Ti-47Al-2Cr-2Nb-0.2W-0.15B(摩尔分数，%)合金在变形温度为1 100~1 250 ℃、应变速率为10−3~100 s−1和变形率为50%条件下的高温变形行为。结果表明：Ti-47Al-2Cr-2Nb- 0.2W-0.15B合金在高温变形初始阶段，流动应力随应变的增加迅速增加；当应变超过一定值后，流变应力开始下降并逐渐趋于稳定，出现稳态流动特征；随着形变温度的升高和应变速率的增加, 合金高温变形时的峰值应力和稳态应力显著降低。利用热模拟压缩实验数据，基于Arrhenius 方程和Zener-Hollomon参数，运用多元回归分析方法建立Ti-47Al-2Cr-2Nb-0.2W-0.15B合金在高温变形过程中的流变应力本构模型。应用DEFORMTM 3D软件验证该流变应力本构模型的有效性，结果表明所得高温流变应力本构模型能够较好地预测Ti-47Al-2Cr-2Nb-0.2W- 0.15B合金的高温变形行为。
关键字: TiAl合金；高温变形行为；本构模型
powder metallurgy TiAl alloy and its constitutive model
（Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China）
Abstract:The high temperature deformation behavior of PM TiAl alloy Ti-47Al-2Cr-2Nb-0.2W-0.15B (mole fraction, %) was investigated by hot compression tests on Gleeble® 3800 machine at the temperature range of 1 100−1 250 ℃, strain rates between 10−3 s−1 and 1 s−1 and deformation rate of 50% of the samples. The results show that the flow stress of the TiAl alloy increases quickly with increasing strain and then reaches a peak, then decreases to a steady value. The steady and peak stress significantly decreases with the increase of the deformation temperature and the decrease of the strain rate. The flow stress model of the TiAl alloy during high temperature deformation was established based on the Arrhenius equations and Zener-Hollomon parameter, the model was validated using the DEFORMTMTM 3D software. And the simulation results indicate that the flow stress constitutive model can efficiently predict the deformation behavior of the TiAl alloy during high temperature deformation.
Key words: TiAl alloy; high temperature deformation behavior; constitutive model
