Publication Date
6-13-2001
Abstract
Morphological instability of the thermally grown oxide (TGO) is a fundamental source of failure in some thermal barrier systems. The instabilities occur when initial non-planarity in the TGO grows in amplitude as the system experiences thermal cycling. By numerical means, this study explores how these instabilities are linked to constituent properties. The associated phenomena involve oxidation of the TGO, plastic flow of the bond coat, thermal expansion misfit between the TGO, bond coat and substrate, and stress relaxation in the TGO at high temperature. A key implication of the simulations is that the incidence of reverse yielding upon reheating differentiates between systems that exhibit a systematic increase in imperfection amplitude upon thermal cycling (ratcheting) and those that exhibit shakedown.
DOI
10.1016/S1359-6454(01)00073-8
Publisher's Statement
NOTICE: this is the author’s version of a work that was accepted for publication in . Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in PUBLICATION, [VOL#, ISSUE#, (DATE)]; NOTICE: this is the author’s version of a work that was accepted for publication in Acta Materialia. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Acta Materialia, 49, 10, June 13, 2001; 10.1016/S1359-6454(01)00073-8
Citation Information
Karlsson, A. M., and Evans, A. G., 2001, "A Numerical Model for the Cyclic Instability of Thermally Grown Oxides in Thermal Barrier Systems," Acta Materialia, 49(10) pp. 1793-1804.
