Crack Analysis of First Stage Turbine Blade in Aero-engine

A first-stage turbine blade in aero-engine cracked at the leading edge during 200 h accelerating trial. The turbine blade was made of K465 superalloy. The engine had worked for 145 h when the crack was found. To find out the failure mode and cause of the blade, appearance observation, fracture observation, metallographic examination and thermal simulation experiment were carried out. The results show the failure mode of the blade is fatigue crack. The crack was caused by over heat because the tenon core had not been completely cleaned and the tenon cooling channel was blocked. Over heat weakened microstructure and property of the blade. As a result, the blade cracked at high temperature region and early failure happened. According to the result of thermal simulation experiment, it is estimated that the temperature of the blade near the crack was over 1 260 ℃.