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

Abstract

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, themore » 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.« less

Authors:
;
Publication Date:
Research Org.:
Oak Ridge National Lab., TN (US)
Sponsoring Org.:
USDOE; Alexander von Humboldt Foundation
OSTI Identifier:
20050507
DOE Contract Number:  
AC05-96OR22464
Resource Type:
Journal Article
Journal Name:
Scripta Materialia
Additional Journal Information:
Journal Volume: 42; Journal Issue: 8; Other Information: PBD: 14 Apr 2000; Journal ID: ISSN 1359-6462
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; RESIDUAL STRESSES; CERAMICS; COATINGS; MATHEMATICAL MODELS; INTERFACES; OXIDES; THERMAL EXPANSION; ELASTICITY; THEORETICAL DATA

Citation Formats

Hsueh, C H, and Fuller, Jr, E R. Analytical modeling of oxide thickness effects on residual stresses in thermal barrier coatings. United States: N. p., 2000. Web. doi:10.1016/S1359-6462(99)00430-3.
Hsueh, C H, & Fuller, Jr, E R. Analytical modeling of oxide thickness effects on residual stresses in thermal barrier coatings. United States. https://doi.org/10.1016/S1359-6462(99)00430-3
Hsueh, C H, and Fuller, Jr, E R. Fri . "Analytical modeling of oxide thickness effects on residual stresses in thermal barrier coatings". United States. https://doi.org/10.1016/S1359-6462(99)00430-3.
@article{osti_20050507,
title = {Analytical modeling of oxide thickness effects on residual stresses in thermal barrier coatings},
author = {Hsueh, C H and Fuller, Jr, E R},
abstractNote = {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.},
doi = {10.1016/S1359-6462(99)00430-3},
url = {https://www.osti.gov/biblio/20050507}, journal = {Scripta Materialia},
issn = {1359-6462},
number = 8,
volume = 42,
place = {United States},
year = {2000},
month = {4}
}