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采用GW-1200A型控制器配合高温加热炉在WDW-300电子万能试验机上通过等温压缩实验研究了Ti600合金在温度为25?800℃、应变速率为10-4和10-3 s-1条件下的热变形行为,获得了该合金在变形过程中的真应力-真应变曲线,建立了该合金的高温本构关系。结果表明:Ti600合金在较高的温度(600和800℃)下流变应力随应变速率增大而增大,在较低温度(25和300℃)时变化不太明显。在一定的应变率条件下,随着温度升高流变应力降低。考虑到Ti600合金在不同温度下的真应力-真应变曲线随温度变化的发展趋势,建立了修正的井上胜郎高温本构关系,与实验结果对比验证了模型是可靠的。通过扫描电镜(SEM)观察发现,在室温准静态压缩条件下Ti600合金的断裂形式以脆性断裂为主,同时在局部区域出现韧性断裂特征。
In this paper, we use the GW-1200A controller and high temperature furnace to test the Ti600 alloy at the temperature of 25 ~ 800 ℃ and the strain rate of 10-4 and 10-3 s-1 on the WDW-300 electronic universal testing machine. The true stress-strain curve of the alloy during deformation was obtained, and the high-temperature constitutive relation of the alloy was established. The results show that the flow stress of Ti600 alloy increases with increasing strain rate at higher temperature (600 and 800 ℃), but not obvious at lower temperature (25 and 300 ℃). At a given strain rate, the flow stress decreases with increasing temperature. Taking into account the trend of the true stress-true strain curve of Ti600 alloy at different temperatures with temperature, a modified constitutive model of well-to-high temperature is established, which is verified by comparison with experimental results. Scanning electron microscopy (SEM) observation shows that the fracture mode of Ti600 alloy mainly consists of brittle fracture under the condition of quasi-static compression at room temperature, and ductile fracture appears in the local area at the same time.