Thermomechanical and Thermal Gradient Mechanical Fatigue Lifetime of Thermal Barrier Coating Systems
Detailed damage analyses of an Y2O3 stabilized ZrO2 top coat (TC)–MCrAlY bond coat (BC)–superalloy thermal barrier coating (TBC) system during thermomechanical fatigue (TMF) and thermal gradient mechanical fatigue (TGMF) tests had been performed in present work. During tests, the lifetime of TBCs was strongly dependent on the strain ranges, pre-oxidation time and the thermal gradient in TBCs. Cracks were initiated in the TGO layer, propagated along the TC/TGO or TGO/BC interface, forming the delamination cracks. When the delamination cracks connected with the segmentation cracks which were initiated and propagated in TC, the TBCs spalled. The failure mechanism and stress were analyzed, which were significantly helpful to establish the TMF/TGMF lifetime prediction model for the TBCs.
Z. J. Zhou et al., "Thermomechanical and Thermal Gradient Mechanical Fatigue Lifetime of Thermal Barrier Coating Systems", Materials Science Forum, Vol. 898, pp. 1524-1531, 2017