Microstructure Damage of Nickel-Based Single Crystal Superalloy Turbine Blade for Aircraft Engine after Service

The cross-sections of different blade heights（blade root, 49% blade height, 60% blade height, 85% blade height）of nickel-based single crystal superalloy high-pressure turbine blade for the aircraft engine after service for a certain period of time were sampled, and the microstructure observation and microhardness test were carried out. Based on the microstructure of the tenon, the microstructure damage at different areas（blade leading edge, blade basin, railing edge, blade back）of the blade and its relationship with the microhardness change were studied. The results show that the leading edge and trailing edge of the blade at the same height were subjected to higher temperature and stress, and the degree of microstructure damage was more significant than that in the blade back and blade basin. The microstructure damage of the leading edge and trailing edge at 49% and 60% blade height was the most serious, especially in the trailing edge area. The degradation of γ´ phase in the trailing edge area at 49% and 60% blade height was significant, which was manifested by the decrease of γ´ phase area fraction, the passivation of particle edges and the re-dissolution of some γ´ phases. The microhardness of the trailing edge area at 49% and 60% blade height was significantly lower than that of the blade back and the blade basin. The re-dissolution and coarsening process of γ´ phase would reduce the microhardness. Under relatively low temperatures or relatively low stresses, γ´ phase particles were relatively stable, the re-dissolution and coarsening phenomenon was relatively rare, and the hardness was relatively high.