| Abstract:In order to provide technical support for the life damage evaluation of high-pressure turbine guide vanes, macroscopic inspec?
tion, fracture analysis, micro-structure inspection, chemical composition analysis, micro-structure thermal simulation test, and over-
temperature mechanical property test were carried out on the cracked IC10 alloy directional solidification high-pressure turbine guide vane to
determine the nature and failure mechanism of the cracks. The results show that the crack nature of the vane is mainly fatigue crack induced by
thermal stress. The fatigue crack originated from the inner cavity surface of the concave side near the film cooling holes and stiffener. The vane
was subjected to periodic thermal stress due to the working environment with varying temperatures and the uneven temperature distribution of
the vane. In addition, through thermal simulation tests, it was inferred that the actual operating temperature at the crack site reached 1175-
1200℃, exceeding the long-term service temperature of 1100℃ of IC10 alloy. The degradation of γ′ phase in the alloy reduced the high-
temperature performance of the vane. The high-temperature tensile test results further indicate that the tensile strength of IC10 alloy
decreased significantly with the increase of temperature and the resistance of the alloy was insufficient in the over-temperature state. The
combined effect of thermal stress and micro-structural degradation led to the initiation and propagation of fatigue cracks. |
