J. Rosler et al., Stress state and failure mechanisms of thermal barrier coatings: Role of creep in thermally grown oxide, ACT MATER, 49(18), 2001, pp. 3659-3670
The mechanical loading of the thermal barrier coating (TBC)/thermally grown
oxide (TGO)/bond coat interface region is calculated for a TBC coated supe
ralloy specimen using a finite element model. It is shown that the evolving
stress state depends crucially on the ratio of the loading rate caused by
growth and swelling of the oxide layer and the unloading rate by creep rela
xation. For grain sizes below I pm, creep of the oxide layer cannot be negl
ected. From this calculations, possible damage scenarios are inferred and i
mplications for future design of TBC layers are considered. Tailoring the T
GO creep properties, for example by reducing its grain size or designing a
multilayer TGO scale, is identified as the most relevant aspect. (C) 2001 A
cta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.