Analysis of the causes of fracture of turbine blades in a gas-compressor unit

The problems of the fatigue life of gas-compressor unit blades are discussed. In particular, the results of fractographic investigation are used to formulate the specific features of fracture of stamped lowpressure turbine blades made of an EI893 alloy, which exhibit the maximum number of damages in a five-year period. In 80% cases, fracture begins with the formation of a brittle zone in the leading edge of a blade airfoil because of the resonance phenomena caused by a break in the stiffness of the blade–turbine disk joint. This conclusion is supported by pronounced traces of fretting corrosion in the contact surfaces of the joint of a failed blade and a disk.