夹杂物尺寸及分布对FGH97高温合金低周疲劳性能的影响

Effect of inclusion size and distribution on Low Cycle Fatigue properties of an FGH97 superalloy

摘要:

利用扫描电子显微镜、能谱仪、金相显微镜、低周疲劳试验机研究了镍基粉末高温合金FGH97材料650℃低周疲劳性能与断口夹杂物尺寸、面积及分布的关系。结果表明：FGH97 热等静压材料低周疲劳断口主要由非金属夹杂物引起。非金属夹杂物尺寸小于临界值（约80μm）时，夹杂物尺寸和位置对650℃/ 最大应力980MPa低周疲劳寿命无明显影响，疲劳寿命均值达到190992周次。当夹杂物尺寸超过临界值（约80μm）时，则夹杂物尺寸越大，越靠近表面，低周疲劳寿命越低。因此，控制夹杂物尺寸是提高FGH97高温合金低周疲劳寿命的有效方法。

Abstract:

Scanning Electron Microscopy, Energy Dispersive Spectroscopy, Metallographic Microscope and Low Cycle Fatigue testing machine were used to study the relationship between the Low Cycle Fatigue performance of 650 °C/ maximum stress 980MPa and the size, area ,distribution of fracture inclusions of a nickel-based FGH97 superalloy. The results show that the low-cycle fatigue fracture is mainly casued by non-metallic inclusions. If the size or area of the non-metallic inclusions is less than a critical value（about 80μm）, there is no significant effect on the low cycle fatigue life of 650 ℃/ maximum stress 980MPa , and the average life value reaches 190,992 cycles. The distribution of inclusions has no significant influence on the low cycle fatigue life when the size is less than the critical value of 80μm.When the size exceeds the critical value, the larger size of inclusion and the closer to surface result in the lower the low cycle fatigue life.