Ti600合金的高温本构方程

Constitutive Equations for Hot Deformation of Ti600 Alloy

采用热模拟压缩试验研究了Ti600合金在变形温度为800～1100℃、应变速率为0.001～10s-1范围内应力-应变曲线的变化规律。研究结果表明:Ti600高温钛合金热变形的流变应力随温度的升高和应变速率的降低而减小;随着应变的增大,合金的真应力-真应变曲线在经历了明显的加工硬化阶段后达到最大值,然后渐渐出现流变“软化”现象。以经典的双曲正弦形式的模型为基础建立了Ti600合金热变形的本构方程,同时也通过对数据回归处理确定了合金不同温度下的应力指数n、应变激活能Q等数值。

The flow stress of Ti600 alloy is measured by upset tests of cylindrical samples in the Gleeble-1500 heat stimulation machine at temperature range of 800～1100℃ and strain rate from 0.001s^-1 to 10s^-1. The results show that the true stress of hot deformation of Ti600 alloy increases with the decrease of the deformational temperature and the increase of the strain rate. With the increase of true strain, for process hardening of the alloy, the true stress attains the peak, and then flow softening occurred. The constitutive equation for hot deformation of Ti600 alloy was obtained on-the basis of hyperbolic sine form model, and the material constants, including activation energy Q, stress exponent n and constant in（A） was also obtained.