某发动机压气机三级转子叶片发生断裂，采用宏观观察、化学成分分析、扫描电镜和能谱分析、金相检验、硬度测试等方法，并结合叶片振动模态分析，对其断裂原因进行分析。结果表明：叶片的断裂性质为疲劳断裂，疲劳起源于叶片叶盆面距离进气边约0.8 mm的腐蚀坑处；腐蚀坑降低了叶片的抗疲劳能力，是叶片发生疲劳断裂的主要原因；叶片在工作转速范围内存在11阶共振，引起叶片疲劳裂纹的萌生和扩展。

The blade of compressor three stage rotor of an engine fractured. The fracture reasons were analyzed by means of macroscopic observation, chemical composition analysis, scanning electron microscope and energy spectrum analysis, metallographic examination, hardness test and blade vibration modal analysis. The results show that the fracture property of the blade was fatigue fracture, and the fatigue originated from the corrosion pit about 0. 8 mm from the inlet side of the vane concave surface. Corrosion pits reduced the fatigue resistance of blades, which was the main reason for fatigue fracture of blades. The blade had 11 order resonance in the working speed range, which caused the initiation and propagation of fatigue cracks in the blade.