The notched fatigue property of the second generation powder metallurgy superalloy FGH96 at 500℃ and 600℃ with two stress ratios was investigated. The test data was fit with S-N curves to analyze differences of Kf between the smooth specimen and the notched one. SEM (scanning electron microscopy) was used to exam the morphology of specimen after fracture. The results indicate that the notch sensitivity of FGH96 is decreased as the elevated temperature and higher stress ratio. Compared to smooth specimen, the fatigue crack of the notched specimen is initiated at machining deficiency, so fatigue life of initiation is shortened. The fatigue stripe is appeared, though the area of crack propagation is smaller than the smooth specimen.%在500℃和600℃两个温度条件下,研究了第二代粉末高温合金FGH96的缺口疲劳性能,将原始数据的曲线拟合成S-N曲线,分析光滑与缺口试样的Kf的差别,用扫描电镜分析了试样的断口形貌特征.结果表明:FGH96合金的疲劳缺口敏感性随着温度的升高和应力比的增大而降低;与光滑试样的断口相比,合金的缺口试样在高温下疲劳裂纹多由加工刀痕起源,因此缩短了其疲劳萌生寿命;疲劳扩展区疲劳条带比较明显,扩展区面积比光滑试样小.
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