WSTi3515S阻燃钛合金超塑性变形行为及本构关系研究

Research on Superplastic Deformation Behavior and Constitutive Relationship of Burn-resistant WSTi3515S Alloy

摘要:

通过电子万能试验机对具有粗大晶粒的β型WSTi3515S阻燃钛合金进行了超塑性拉伸试验，分析了热力学参数对超塑性能及力学行为的影响，建立了该合金超塑性本构关系。结果表明：WSTi3515S阻燃钛合金可在较宽的温度范围及应变速率区间内(800~920 ℃,0.000 5~0.01 s-1)实现超塑性；且在高温低应变速率条件下超塑性能良好，最大延伸率可达556%。与细晶超塑性不同，WSTi3515S合金在超塑性拉伸过程中，稳态变形阶段很短甚至不出现，变形主要集中在准稳态变形阶段，且准稳态变形阶段越长，获得延伸率越大。基于Arrhenius方程建立的本构方程精度不高，而由逐步回归法构建的本构方程误差值基本在5%以内。

Abstract:

The superplastic tensile tests of burnresistant WSTi3515S alloy with large grains were conducted on electronic universal testing machine.The effect of thermodynamic parameters on superplastic properties and mechanical behavior was analyzed,and the superplastic constitutive equation of the alloy was established.The results show that WSTi3515S alloy has superplasticity in a wide temperature and strain rate range ie.800~920 ℃ and 0.000 5~0.01 s-1 respectively with the maximum elongation of 556% at high temperature and low strain rate.Different from finegrained superplasticity,the steady state deformation stage in the true stressstrain curves during the superplastic tensile tests is very short or even absent.The deformation is mainly concentrated in the quasisteady state deformation stage.Moreover,the longer the quasi steady state deformation stage,the larger elongation is obtained.The constitutive equation of WSTi3515S alloy is constructed by Arrhenius equation and stepwise regression respectively.Error analysis shows that the constitutive equation constructed by the stepwise regression has a good accuracy,and the error value is less than 5%.