Crack analysis of the fourth-stage compressor blades

In the medium-term inspection of an engine after the first overhauling, cracks were found in the tenon of the fourth-stage compressor blades. In addition to visual examination, other experimental investigation techniques were crack morphology and fracture characteristics by video microscope and scanning electron microscopy, metallographic observation of the cracks, and energy spectrum analysis. The results were obtained through the analysis of the processing and experimental data. The cracks are all fatigue cracks with multisource and line source, the main reason of which is concerned with higher contact stress during the assembly process after the first overhauling. The fretting wear between the tenon and the tenon-groove mating surface promotes crack initiation, which was unrelated to the material and processing.