The Combined Effect of Creep and TGO Growth on the Cracking Driving Force in a Plasma-Sprayed Thermal Barrier System
- 84 Downloads
A comprehensive understanding of the failure mechanisms of plasma-sprayed thermal barrier coatings (TBCs) under temperature cycling is a prerequisite for developing the next advanced gas turbine with prolonged thermal cyclic lifetime. In this study, a finite element model including the dynamic growth of thermally grown oxide (TGO) is proposed to explore the combined effect of creep and TGO growth on the cracking driving force in TBCs. A different group of material configurations is designed to satisfy the objective. An adapted interface element based on the virtual crack closure technique is proposed to obtain the strain energy release rate, namely cracking driving force, and crack growth is assessed using a mixed-mode criterion. The results reveal that the cracking predicted by the simulation is in line with the experiment results. Two possible mechanisms of crack coalescence are proposed. The increase in TGO lateral growth strain will induce premature coating spallation. The bond coat and TGO creep only have a slight impact on the ceramic cracking if a comparatively low TGO growth stress is included. Hence, coating optimization suggested in this study may provide additional options for the development of TBCs with extended thermal cyclic lifetime.
Keywordscracking driving force creep behavior thermal barrier coatings system (TBCs) thermally grown oxide (TGO) growth virtual crack closure technique (VCCT)
The present project is financially supported by the National Science Foundation of China (No. 51671159), the National Basic Research Program of China (No. 2012CB625100), the Fundamental Research Funds for the Central Universities and the National Program for Support of Top-notch Young Professionals.
- 3.K. Knipe, A. Manero Ii, S.F. Siddiqui, C. Meid, J. Wischek, J. Okasinski, J. Almer, A.M. Karlsson, M. Bartsch, and S. Raghavan, Strain Response of Thermal Barrier Coatings Captured under Extreme Engine Environments through Synchrotron X-ray Diffraction, Nat. Commun., 2014, 5, p 4559CrossRefGoogle Scholar
- 21.Q. Zhang, Study on Oxidation Behavior of Cold-Sprayed MCrALY Superalloy Bond Coating for Thermal Barrier Coatings, Xi’an jiaotong University, Xi’an, 2009, p 36-37Google Scholar
- 43.J. Rösler, M. Bäker, and K. Aufzug, A Parametric Study of the Stress State of Thermal Barrier Coatings Part I: Creep relaxation, Acta Mater., 2004, 52(16), p 4809-4817Google Scholar
- 47.L. Wang, Y.X. Zhao, X.H. Zhong, S.Y. Tao, W. Zhang, and Y. Wang, Influence of “Island-Like” Oxides in the Bond-Coat on the Stress and Failure Patterns of the Thermal-Barrier Coatings Fabricated by Atmospheric Plasma Spraying During Long-Term High Temperature Oxidation, J. Therm. Spray Technol., 2013, 23(3), p 431-446CrossRefGoogle Scholar
- 59.ABAQUS, Version 6.14 Documentation, Dassault Systemes Simulia Corp. Providence, RI, USA, 2014Google Scholar
- 63.H. Dong, Thermal Cyclic Lifetime and Crack Propagation Behavior of Plasma-Sprayed Thermal Barrier Coatings, Xi’an jiaotong University, Xi’an, 2013, p 47-48Google Scholar