某型发动机高压压气机叶片开裂原因分析

Failure Analysis of High-pressure Compressor Blades in Aero-engine

某发动机高压压气机GH150合金叶片在进行振动疲劳试验时发生开裂,为分析叶片开裂原因,对开裂叶片进行了外观检查、断口宏微观观察、能谱分析、显微组织检查和硬度测试。结果表明,叶片的断裂性质为弯曲振动疲劳。开裂叶片的显微组织和硬度均符合技术要求,叶片的开裂与原材料质量无关。三片叶片的开裂与叶身表面存在氧化缺陷、表面晶界弱化、加工质量不好以及在轧制过程中形成的微小裂纹等加工缺陷有关。缺陷起到疲劳源的作用,从而使叶片很快萌生裂纹并扩展。通过严格控制轧制工艺参数、表面抛磨时的工作液质量和磨料形状,有效的解决了叶片表面存在缺陷的问题,从而保证了叶片的质量。

Three high-pressure compressor blades of GH150 alloy cracked during vibration fatigue test.Appearance test,fracture characteristics observations,energy spectrum analysis,microstructure observation and hardness test were performed for the cracked blades.The results show that the fracture mode of the cracked blades is bending vibration fatigue.The microstructure and hardness of the cracked blades all meet with technical requirements.The fatigue failure has no connection with the material quality.The major factors leading to the blades crack are that there are some defects on the surface of the blade,such as oxide defects,surfaced grain-boundary weakness,poor machining quality and tiny cracks formed in rolling process.The defects are the fracture sources,and the cracks initiated quickly and propagated with test loading.The quality of the blades were advanced through controlling parameter of rolling processing,operating fluid quality and abrasive material shape of blade surface treatment.