Analytical modeling of oxide thickness effects on residual stresses in thermal barrier coatings

Journal Article · Fri Apr 14 04:00:00 EDT 2000 · Scripta Materialia

DOI:https://doi.org/10.1016/S1359-6462(99)00430-3· OSTI ID:20050507

Hsueh, C H; Fuller, Jr, E R

During high temperature operation, an oxide scale forms along the irregular top coat/bond coat interface in the plasma-sprayed thermal barrier coating (TBC) system. The residual stresses in the system are affected by the presence of the thermally grown oxide (TGO). Along the irregular interface, the asperity can be convex or concave. Semicircular convex and concave asperities have been adopted for numerical simulations to examine the effects of the TGO thickness on residual thermal stresses. It was found that in the tip region of a convex asperity, the residual stress normal to the interface, {sigma}{sub y}, in the ceramic top coat is tensile for a thin oxide but becomes compressive for a thick oxide. In the tip region of a concave asperity, {sigma}{sub y} in the ceramic topcoat is compressive for a thin oxide and becomes less compressive for a thick oxide. The purpose of the present study was to explore the physical meaning of the trend of the stress state of {sigma}{sub y} in the ceramic topcoat with the variation of the TGO thickness. To achieve this, a simple analytical model of three concentric circles was adopted. First, the residual thermal stresses in the three-concentric-circles model were derived. Then, the results for residual radial stresses at the top coat/TGO and the TGO/bond coat interfaces as functions of the TGO thickness were presented. Also, the physical meaning of the above results was discussed.

• Research Organization: Oak Ridge National Lab., TN (US)
• Sponsoring Organization: US Department of Energy; Alexander von Humboldt Foundation
• DOE Contract Number: AC05-96OR22464
• OSTI ID: 20050507
• Journal Information: Scripta Materialia, Journal Name: Scripta Materialia Journal Issue: 8 Vol. 42; ISSN 1359-6462; ISSN SCMAF7
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CERAMICS
COATINGS
ELASTICITY
INTERFACES
MATHEMATICAL MODELS
OXIDES
RESIDUAL STRESSES
THEORETICAL DATA
THERMAL EXPANSION