新型TA32钛合金板的高温拉伸变形行为

在变形温度650～850℃、应变速率0.001～0.100s-1条件下对TA32钛合金板进行高温拉伸试验,研究了变形温度和应变速率对合金高温拉伸变形行为的影响;基于修正的Hooke定律和Grosman方程建立TA32钛合金的高温流变本构方程并进行试验验证。结果表明:TA32钛合金的流变应力受变形温度和应变速率的影响显著,变形温度的升高和应变速率的降低均会使流变应力减小;在变形温度650℃、应变速率0.100s-1下,合金的抗拉强度为680 MPa,约为常温抗拉强度的80%,合金仍具有较高的强度;当变形温度由750℃升至850℃时,合金伸长率的增长幅度和强度的下降幅度均较明显,合金塑性较好;采用建立的高温流变本构方程计算得到的真应力-真应变曲线与试验结果基本吻合,其相关系数和平均相对误差分别为0.979 4和11.1%,该本构模型可较好地描述TA32钛合金的高温拉伸变形行为。

High Temperature Tensile Deformation Behavior of New Titanium Alloy Sheet TA32

High temperature tensile tests at deformation temperatures of 650-850 ℃ and strain rates of0.001-0.100s^-1 were conducted on TA32 titanium alloy sheet.The influence of deformation temperature and strain rate on high temperature tensile deformation behavior of the alloy was investigated.The high temperature rheological constitutive model of TA32 titanium alloy was established on the basis of modified Hooke law and Grosman equation,and verified by tests.The results show that the flow stress of TA32 titanium alloy was significantly affected by the deformation temperature and strain rate.The flow stress decreased with the increase of deformation temperature and the decrease of strain rate.The tensile strength of the alloy reached 680 MPa at the deformation temperature of 650℃ and strain rates of 0.100s^-1,which was about 80% of the tensile strength at room temperature;the alloy still had the relatively high strength.When the deformation temperature increased from750℃to 850℃,the elongation increased and the strength decreased obviously,indicating the alloy had relatively good plasticity.The true stress-true strain curves calculated by the established high temperature rheological constitutive equation were in agreement with the tested results,and the correlation coefficient and average relative error were 0.979 4and 11.1%,respectively,indicating that the constitutive model could describe the high temperature tensile deformation behavior of TA32 titanium alloy.