疲劳保载时间与固溶处理对PM René95合金高温裂纹扩展速率的影响

EFFECTS OF FATIGUE DWELL TIME AND SOLID SOLU- TION ON CRACK GROWTH RATE OF PM René95 SUPERALLOY AT HIGH TEMPERATURE

经不同固溶时效处理的 ＰＭ Ｒｅｎｅ９５合金于 ６５０℃分别在蠕变、保载 ５和 ９０ ｓ疲劳载荷条件下进行了裂纹扩展速率实验．结果表明，相同热处理制度下，疲劳保载时间越长，裂纹扩展速率越高；相同载荷条件下，增加一次高温固溶并缓冷，有利于降低合金的裂纹扩展速率，且固溶温度越高裂纹扩展速率越低；１２００℃一次固溶缓冷并于１１６０℃二次固溶热处理比１１４０℃一次固溶的裂纹扩展速率约降低一个数量级；基体晶粒尺寸适当加大，强化相粒子γｃ数量增加、形状趋于田字形，有利于降低裂纹扩展速率.

The crack growth rates (CGR) of PM Rene 95 superalloy treated by different solid solution conditions are tested under creep, fatigue with 5 s and 90 s dwell time at 650℃. The results indicate that the longer fatigue dwell time is, the higher CGR is; the additional solid solution treatment at the temperature nearly to the solution point of A benefits to decrease CGR and the higher solution temperature is, the lower CGR is; the greater grain size of matrix and more γ'c result in the lower CGR.