ISSN: 0884-6804
CODEN: JCTRER
Page Count: 9

Modeling of Thermal Stresses in Yttrium Aluminum Garnet and Alumina Fibers Coated with β″-Alumina
Ellenburg, MG
Graduate student, Georgia Institute of Technology, GA

Lackey, WJ
Professor, George W. Woodruff School of Mechanical Engineering, GA

(Received 7 October 1996; accepted 13 July 1999)

Abstract

Since layered aluminate coatings such as β″-alumina are being considered for tailoring the interfacial properties of oxidation-resistant fiber-reinforced composites, stresses arising from thermal expansion mismatch were calculated for the substrate fiber and coating. Both isotropic and anisotropic β″-alumina coatings were analyzed for yttrium aluminum garnet and single crystal and polycrystalline alumina fibers. It was possible to rank the various fiber-coating combinations in terms of the magnitude of maximum tensile stresses present in the coating. Polycrystalline alumina + isotropic β″-alumina yielded the lowest tensile stresses with radial stress on the order of 10 MPa, while single crystal alumina + anisotropic β″-alumina yielded the highest tensile stresses with tangential stress on the order of >100 MPa.

Keywords:
ceramic matrix composites, interface coatings, fibers, stress

Paper ID: CTR10982J
DOI: 10.1520/CTR10982J
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