Hot Deformation Behavior and Hot Processing Map of As-Cast Udimet720Li Alloy
Hot compression tests of as-cast Udimet720Li superalloy were carried out at deformation temperature of 1 040～1 160 ℃,strain rate of 0.01～10 s-1and height reduction of 60％.Based on the stress-strain data,the constitutive equation model and hot processing map were established by using Arrhenius equation,dynamic material model theory and flow instability criterion theory.The hot deformation behavior of the alloy was analyzed and the accuracy of the hot processing map was verified by the microstructure.The results show that the flow stress has a strong sensitivity to temperature and strain rate.With the increase of deformation temperature and the decrease of deformation rate,the flow stress decreases continuously.The higher the temperature,the smaller the corresponding stress and strain when the flow stress reaches the steady state.The constitutive equation has a high accuracy in predicting the flow stress of the alloy.When the height reduction is 60％,the alloy is in the deformation instability zone in the range of deformation temperature 1 040～1 070 ℃ and strain rate 5～10 s-1,and the alloy has the best hot workability in the range of 1 140～1 160 ℃ and 0.01～0.20 s-1.The power dissipation coefficient in this area is 0.32～0.40,and the alloy can obtain equiaxed uniform crystal structure with fine grains.
万方数据
维普
