【摘要】 采用Gleeble-1500热模拟试验机对V-5Cr-5Ti合金进行了热模拟压缩试验。研究了V-5Cr-5Ti合金在变形温度为1373~1493 K、应变速率为0.1~30.0 s-1工艺条件下的流变行为,建立了合金高温变形的流变应力模型和加工图,并观察了合金变形后的金相组织。研究结果表明:流变应力和峰值应变随变形温度的降低和应变速率的提高而增大。以热模拟压缩试验为基础,通过对真应力-应变曲线的分析与计算得到了V-5Cr-5Ti合金的热变形激活能Q值为468.25 k J·mol-1,建立了V-5Cr-5Ti合金高温变形的流变应力模型。同时,建立了描述V-5Cr-5Ti合金热加工性能的热加工图,其由3部分组成,即Ⅰ变形安全区,Ⅱ变形安全区以及流变失稳区,其中流变失稳区呈对角线连续分布。在绘制、分析V-5Cr-5Ti合金的热加工图的基础上,结合组织分析得出,V-5Cr-5Ti合金最适合在Ⅱ变形安全区内采用液压机进行变形加工。更多还原

【Abstract】 The flow stress features of V-5Cr-5Ti alloy were studied by isothermal compression of cylindrical specimen in the temperature range of 1373 ~ 1493 K and strain rate range of 0. 1 ~ 30. 0 s- 1with Gleeble-1500 simulated machine. The high temperature deformation constitutive equations and processing map were established,furthermore,the metallographic structures were investigated after deformation. The results showed that the flow stress and steady strain increased with the deformation temperature decreasing and strain rate increasing. Based on the isothermal compression experiment,the thermal deformation activation energy( Q) was obtained as 468. 25 kJ ·mol- 1by analyzing and calculating the curves of true-stress and true-stain. The flow stress model of hot deformation V-5Cr-5Ti alloy was constructed. Meanwhile,the processing map of high temperature deformation of V-5Cr-5Ti alloy was established. The map consisted of three parts,including deformation regionⅠ,deformation region Ⅱand flow instability region,and the flow instability region was diagonally continuous distribution. Based on drawing and analyzing the thermal processing map of V-5Cr-5Ti alloy and the analysis of the structure,the most suitable deformation method for V-5Cr-5Ti alloy was the deformation in deformation region Ⅱ using hydraulic machine.更多还原