Targeting the characteristics of thermal barrier coatings (TBCs) prepared by electron beam-physical vapor deposition (EB-PVD) of complex structure

the Walker viscoplastic constitutive model was used to realize the accurate description of the high temperature mechanical behavior of TBCs structure. Tube specimens with blade curvature feature were selected for numerical analysis with reference to the actual engine load characteristics. The effect of the interface shape and the thickness of thermal growth oxide (TGO) on stress field of EB-PVD coating were focused on. The calculating results show that the stress field of TBCs structure changes little at the linear interface

while the amplitude of stress field can be changed up to 2 times at the cosine interface. The absolute value of stress at top coat increases due to the presence of the TGO. The valley at the interface is always subject to radial compressive stress no matter of circulation to the highest temperature 1050℃ or cooling to 100℃

therefore the valley is not easy to be damaged; while the stress at the peak is relatively large

furthermore

the stress state is easy to form part of the damage. As a result

the peak is a point for easy failure and destruction of the ceramic layer.