【摘要】 为了为两种我国广泛运用于航天发动机各部件的GH4169和GH4586镍基高温合金在面临苛刻服役条件下的安全使用提供依据，采用高频疲劳试验机测试了两种合金在800℃下的疲劳性能并绘制了S-N曲线，采用扫描电镜对它们的疲劳断口形貌进行了观察，结合显微组织观察分析了800℃下两种合金的疲劳断裂特征。结果表明：在800℃下，GH4169合金中长径比较大的针状δ相会引发应力集中，影响其疲劳性能；GH4586合金晶界处稳定的颗粒状TiN对蠕变的抑制及其与细小碳化物第二相强化的共同作用可提高合金的疲劳性能。GH4169和GH4586合金在800℃下的平均疲劳强度极限分别为363.33和490.00 MPa。更多还原

【Abstract】 In order to provide a basis for the safe use of GH4169 and GH4586 nickel based superalloys which widely used in various components of aerospace engines in China under harsh service conditions, the fatigue properties of the two alloys at 800 ℃ was tested using a high-frequency fatigue testing machine and S-N curves were drawn. The fatigue fracture morphology of the two alloys was observed using scanning electron microscopy, and the fatigue fracture characteristics of the two alloys at 800 ℃ were analyzed by microstructure observation. The results show that at 800 ℃, the needle-like δ phase with large aspect ratio in the GH4169 alloy induces stress concentration, which affects its fatigue properties, and the inhibition of creep by the stable granular TiN at the grain boundaries of the GH4586 alloy and its combination with the second phase strengthening effect of TiN particles and fine carbides are the main reasons for the superior fatigue properties of the GH4586 alloy. The average fatigue strength limits of the GH4169 and GH4586 alloys at 800 ℃ are 363.33 and 490.00 MPa, respectively.更多还原