耦合氢含量的置氢Ti65高温钛合金本构方程

Constitutive equation on hydrogenated Ti65 high-temperature titanium alloy coupled with hydrogen content

为了研究置氢处理对Ti65高温钛合金的热变形行为的影响,利用Gleeble-3500热模拟实验机,对不同氢含量的试样分别在α+β两相区和β单相区进行了高温压缩实验。结果表明:置氢与未置氢试样在两相区和单相区具有相似的流变特征,两相区和单相区变形时的主要软化机制分别为α相动态再结晶和β相动态回复,置氢促进了Ti65高温钛合金的动态再结晶软化。0.13 wt.%氢可将Ti65高温钛合金在910℃、1 s^(-1)变形时的变形抗力降低约104 MPa,显著改善了Ti65高温钛合金的热加工性能。基于实验结果,采用多项式拟合方法构建Arrhenius本构方程,确定各参数与氢含量之间的关系,分别在α+β两相区和β单相区建立了耦合氢含量的Ti65高温钛合金本构方程,方程的平均相对绝对误差分别为9.41%和6.68%,表明所建立的本构方程能较为准确地预测含氢Ti65高温钛合金的流动应力,为制定和优化局部置氢钛合金零件的成形工艺提供理论依据。

To study the influence of hydrogenation on the hot deformation behavior of Ti65 high-temperature titanium alloy,the high temperature compression tests of the samples with different hydrogen contents in theα+βtwo-phase region andβsingle-phase region were carried out by hot simulation experiment machine Gleeble-3500,respectively.The results show that the hydrogenated and unhydrogenated samples have similar rheological characteristics in the two-phase region and single-phase region,and the main softening mechanism in the two-phase region is dynamic recrystallization(DRX)ofαphase and in the single-phase region is dynamic recovery(DRV)ofβphase.Hydrogenation promotes the dynamic recrystallization softening of Ti65 high-temperature titanium alloy,and the deformation resistance of Ti65 high-temperature titanium alloy at 910℃and 1 s^(-1) reduces near 104 MPa by adding 0.13 wt.%hydrogen,which significantly improves the hot workability of Ti65 high-temperature titanium alloy.Based on the experimental results,the Arrhenius constitutive equation is constructed by polynomial fitting method,and the relationships between various parameters and hydrogen content are determined.The constitutive equations of Ti65 high-temperature titanium alloy coupled with hydrogen content in theα+βtwo-phase region andβsinglephase region are established by the polynomial fitting,and the average relative absolute errors of these equations are 9.41%and 6.68%,respectively.Thus,the established constitutive equations can accurately predict the rheological stress of hydrogenated Ti65 high-temperature titanium alloy,and provide a theoretical basis for formulating and optimizing the forming process of locally hydrogenated titanium alloy parts.