航空发动机高压压气机三级转子叶片掉角分析

航空发动机在工厂试车后,检查发现高压压气机第三级转子叶片出现掉角故障。对故障件进行组织分析和断口观察,确认叶片掉角的性质,对可能导致故障产生的因素进行分析。结果表明:断口呈现多源疲劳特征,裂纹起源于叶背处,源区未见明显的冶金和加工缺陷;但存在明显的碰磨,断口因受到研磨而变得光滑,能谱分析未见外来元素。分析认为,叶片与机匣之间的不均匀非正常碰磨使振动加剧,引起共振,致使疲劳在叶背处产生并扩展,促进疲劳裂纹的产生和扩展,最终导致掉角。

Failure Analysis of Third-stage Rotor Blade of High-pressure Compressor in Aero-engine

A third-stage rotor blade of the high-pressure compressor in an aero-engine was found to have lost an angle after testing. The failure mode and factors were analyzed by fracture surface analysis, microstructure examination, and mechanical properties testing. The results show that the fracture surface presented the characteristic of multi-source fatigue. The crack initiated from the back side of the blade. No metallurgical and machining defects were found at the fracture source zones. However, obvious collision and friction trace can be seen on the fracture surface. The fracture became smooth because of the collision and friction. No other new elements other than the matrix elements in TA11 alloy were detected by EDS. It is assumed that long time asymmetrical collision and friction between the blade and casing increased the vibration and induced the sympathetic vibration, which led to the initiation and promulgation of the fatigue crack. Finally, angle loss happened.