Effect of Cooling Rate on Stress Build-up in TBCs during Thermal Cycling

Thermal Barrier Coatings (TBCs) are commonly used as protective coatings for engine components and these are susceptible to delamination failures due to large thermal gradient. These failures, which occur within the TBC layer, are very different in character from those associated with the thermally grown oxide [1]. A two-dimensional plane strain finite element simulations are carried-out to study the three possible causes of delamination due to residual stress buildup during thermal cycling. In all cases, temperature dependent thermo-mechanical properties of the TBCs are considered. The effect of three different cooling rates on these failure modes is discussed. It has been found that the edge related delamination with thermal gradient is the most probable failure mechanism. The failure mechanisms predicted matches with the experimental and simulated results available in open literature.