Thermal Stress Analysis on Thermal Barrier Coatings Based on Real Three-dimensional Structure of Thermally Grown Oxide

Thermal barrier coatings (TBCs) after high temperature cycles were imaged with a high resolution of 0.5 μm by X-ray microscope. Three-dimensional (3D) segmentation and extraction of thermally grown oxide (TGO) were performed. A finite element analysis model of the TBCs was established based on real 3D structure of TGO, and the effects of creep and thermal cycles on the stress distribution of the TBCs were studied. The result of finite element analysis shows that the stress decreases greatly due to the influence of creep at the keeping stage. High temperature creep can release the thermal stress of TBCs. The result of 3D thermal stress distribution shows that the thermal stress at the interface between the bond coat and the TGO is the maximum. The stress of TBCs increases with the increase of thermal cycle number, but it tends to be stable after 15 thermal cycles. © 2018, Science Press. All right reserved.