| 刘双博,胡卫兵*,温志勋,李飞,李振威.镍基单晶气膜孔结构疲劳断裂行为研究[J].实验力学,2021,36(6):838~848 |
| 镍基单晶气膜孔结构疲劳断裂行为研究 |
| Study on fatigue fracture behavior in film cooling hole structure of nickel-based single crystal |
| 投稿时间：2020-09-22 修订日期：2020-12-22 |
| DOI：10.7520/1001-4888-20-196 |
| 中文关键词: 镍基单晶 气膜孔 疲劳 裂纹 频率 |
| 英文关键词:nickel-based single crystal film cooling hole fatigue crack frequency |
| 基金项目:国家自然科学基金(51875462)资助 |
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| 中文摘要: |
| 为研究镍基单晶高温合金气膜孔结构疲劳断裂行为，将气膜孔试样在900℃、两种应力水平下进行了频率为3Hz、6Hz、10Hz的高温疲劳试验。借助扫描电子显微镜并考虑加载频率的影响分析了气膜孔结构疲劳裂纹扩展路径、裂纹微观组织特征和断口形貌特征。结果表明不同条件下疲劳裂纹微观组织具有相似的特征，疲劳断口正断面破坏特征基本相同。加载频率对疲劳裂纹扩展及疲劳寿命有一定的影响，520MPa下疲劳寿命高于550MPa疲劳寿命。疲劳断裂路径的总体趋势为：裂纹从孔周萌生，先是垂直于加载轴方向扩展，然后沿与加载轴方向大致呈45°的方向扩展，局部侧断面形貌略有差异。 |
| 英文摘要: |
| In order to study the fatigue fracture behavior in film cooling hole structure of nickel-based single crystal superalloys, high-temperature fatigue tests under two stress levels were carried out on specimens with film cooling hole at a temperature of 900℃ and frequencies of 3Hz, 6Hz and 10Hz. With the aid of scanning electron microscope and considering the influence of loading frequency, the fatigue crack propagation path, the crack microstructure characteristics and the fracture morphology characteristics of the film cooling hole structure are analyzed. The results show that the microstructure of fatigue crack has similar characteristics under different conditions, and the fracture characteristics of normal section of fatigue fracture are basically the same. Loading frequency has a certain effect on fatigue crack propagation and fatigue life. The fatigue life at 520mpa is higher than that at 550MPa. The general trend of the fatigue fracture path is that the crack initiates from the hole, first propagates perpendicular to the loading axis, then propagates along the direction of 45° with the loading axis, but the local side section morphology is slightly different. |
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