Research on the Stability of Thermal Barrier Coatings under Thermal Cyclic Loading

Abstract:

Thermal barrier coating systems (TBCs) are widely used in turbines. However, premature failures have impaired the use of TBCs and cut down their lifetime. The thermally grown oxide layer (TGO) thickening and the material thermal expansion misfit under thermal cyclic loading significantly affect the interfacial stress field and stability of TBCs. In this study, the stability evaluation method of TBCs under thermal cyclic loading based on energy is established using the visco-elastoplastic and shakedown theorem. The semicircular shape interface is used to simplify the complicated interfacial undulations in FEA model. And actual TGO thickness obtained from experiment is used to simulate the bond coat oxidation. Then the effect of TGO thickening on the stability and stress field of TBCs under thermal cyclic loading is analyzed through the numerical simulation. It is concluded that estimating from the stress-strain evolution behavior, the local stability of the TBCs decreases with the TGO thickening, and assessing from energy, TBCs shows instable with TGO thickening.

• Periodical: Key Engineering Materials (Volume 730)
• Pages: 75-80
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.730.75
• Online since: February 2017
• Authors: Jian Sun*, Ying Qiang Xu, Wan Zhong Li, Kai Lv
• Keywords: Energy, Oxide Growth, Residual Stress, Stability, Thermal Barrier Coating

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