Failure behaviors of TBCs on Ni₃Al base alloy IC6A during room temperature tensile test and stress rupture test under the condition of 1100 °C/100 MPa

The failure behaviors of thermal barrier coatings (TBCs) during room temperature tensile test and 1100 °C stress rupture test have been studied in the present investigation. The TBCs were prepared by electron beam physical vapor deposition (EB-PVD). The experimental results showed that during room temperature tensile test cracks initiated from the concave area of the bond coat surface, as well as the interface between the bond coat and the alloy substrate. The cracks may originate from the internal stress arising from the mechanical property differences between the bond coat and the substrate alloy. The similar failure of TBCs and the diffusion of Mo from the alloy substrate to TBCs were observed while in the case of high temperature stress rupture test, however, the failure of TBCs was not as serious as that in the case of room temperature tensile tests and the reason may be attributed to the formation of diffusion zone between the bond coat and the substrate alloy.