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中文摘要: 采用Gleeble-3800热模拟压缩试验机研究了高氧TC4钛合金在温度为990~1 030 ℃、应变速率为0.01~1.0 s-1、变形量为60%时的变形行为及微观组织特征，并构建了该合金的本构方程。结果表明，高氧TC4钛合金在β单相区变形时随着应变速率的增加和变形温度的降低，其流动应力显著增加，该合金在β相区的变形激活能为141 kJ/mol。在990~1 030 ℃加热温度下，原始β晶粒尺寸在250~255 μm范围内，晶粒尺寸对温度不敏感。随着应变速率的增大，原始β晶粒沿着垂直于压缩轴方向被拉长，在被拉长的原始β晶界上可观察到β再结晶晶粒。
Abstract:Isothermal compression of TC4 titanium alloy with high oxygen was carried out on a Gleeble-3800 simulator over the temperature range of 990~1 030 ℃ and strain rate of 0.01~1.0 s-1, with the maximum height reduction of 60%. The hot deformation behavior was characterized based on an analysis of the stress strain behavior and microstructures. Based on the experimental data, a hyperbolic sine constitutive equation was also developed. It was found that the flow stress of the alloy increases with increasing strain rate and decreasing deformation temperature. The activation energy for deformation was 141 kJ/mol in β region. The grain size in the range of 250~255 μm and it is not sensitive to the heating temperature in the range of 990~1 030 ℃. The prior β grains become elongated in the plane perpendicular to the forging direction and dynamic recrystallization grains are observed along the grain boundaries with increasing strain rate.
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