Fatigue behavior of a thermal barrier coated superalloy at $800 ^0 C$

Fatigue testing of thermal barrier coated (TBC), bond coated only and bare Superni C263 superalloy was conducted at $800 ^0 C$ in air. Results reveal that the endurance limits for the TBC and bond coated substrate was substantially higher than that of the base alloy, while the opposite was found for high stress, low cyclic life times. It appears that the increase in endurance limit for the TBC and bond coated superalloy is due to load shifting to the bond coat, and the premature failure for these two materials is possibly due to high stress crack imitation/growth in the TBC/bond coat layers.