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1.0s-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.
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