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为了降低U720Li镍基合金锻造强度,通过改变γ'相的组织形态和析出数量的方法,研究1130℃下保温10、20和30 h后γ'相的析出形态、体积分数和显微硬度的影响,并对其进行1100～1170℃,变形速率1.0 s-1和50%变形量的热变形。结果表明,当保温30 h后,合金中γ'相形貌由方形向圆形转变,γ'相尺寸长大,体积含量最小,具有较小的流变应力。在1130℃保温30 h条件下,当变形温度低于1150℃时,析出的γ'相数量越多,对位错的阻碍作用越强烈,流变抗力越大;当变形温度超过1150℃时,合金中γ'相溶解,此时变形温度越高,合金的流变抗力越低。同时在较低温度下变形,因γ'相对晶界迁移的阻碍作用,再结晶晶粒尺寸较小,而在高温下变形再结晶晶粒长大,温度越高,再结晶晶粒越大。
In order to reduce the forging strength of U720Li Ni-based alloy, the influence of precipitation morphology, volume fraction and microhardness of γ 'phase at 1130 ℃ for 10, 20 and 30 h was investigated by changing the microstructure and amount of γ' phase. , And subjected to thermal deformation of 1100 ~ 1170 ℃, deformation rate of 1.0 s-1 and deformation of 50%. The results show that when the temperature is kept for 30 h, the γ 'phase morphology of the alloy changes from square to circle, the size of γ' phase grows up, the volume content is the smallest, and the flow stress is small. When the deformation temperature is lower than 1150 ℃, the more γ'phase precipitated at 1130 ℃ for 30 h, the more hindered the dislocation and the greater the rheological resistance. When the deformation temperature exceeds 1150 ℃, Alloy γ 'phase dissolution, the higher the deformation temperature at this time, the lower the rheological resistance of the alloy. At the same time, it deforms at lower temperature, and the recrystallized grain size is smaller due to the obstruction of the γ 'relative to the grain boundary migration. At high temperature, the recrystallized grain grows up and the higher the recrystallization grain size is, the larger the recrystallization grain size is.