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基于航空发动机叶片基本失效形式,开发了悬臂梁式弯曲振动超声疲劳试验系统(激振频率20kHz),设计了能模拟叶片振动、适合于超高周弯曲振动疲劳试验的试件.利用该系统开展了钛合金TC17超高周弯曲振动疲劳试验研究,分析了断口的金相图.结果发现:裂纹萌生有表面和次表面两种模式,并不依赖于内部夹杂和缺陷,没有发现内部裂纹萌生迹象,次表面裂纹扩展也不呈“鱼眼”形貌.与文献所述的“鱼眼”形貌特征不同.
Based on the basic failure modes of aeroengine blades, an ultrasonic fatigue test system of bending vibration of cantilever beam (excitation frequency of 20 kHz) was developed and a specimen designed to simulate blade vibration and suitable for fatigue test of ultra-high cycle bending vibration was designed. The ultrahigh-cycle bending vibration fatigue test of titanium alloy TC17 was carried out, and the metallographic picture of the fracture was analyzed. It was found that there were two kinds of modes of surface initiation and subsurface initiation, which did not depend on internal inclusions and defects. , The sub-surface crack propagation is not “fish-eye” morphology, which is different from the “fish-eye” morphology described in the literature.