Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 2 of 2
Full-Text Articles in Mechanical Engineering
Aspects Of The Morphological Evolution In Thermal Barrier Coatings And The Intrinsic Thermal Mismatch Therein, J. Shi, S. Darzens, Anette M. Karlsson
Aspects Of The Morphological Evolution In Thermal Barrier Coatings And The Intrinsic Thermal Mismatch Therein, J. Shi, S. Darzens, Anette M. Karlsson
Mechanical Engineering Faculty Publications
The evolution of interfacial deformations and stresses in thermal barrier coatings due to the formation of the thermally grown oxide and the intrinsic thermal mismatch is investigated. The study focuses on systems that are prone to displacement instabilities of the thermally grown oxide and numerical models spanning a range of properties are investigated. Material changes in the Pt-modified aluminide bond-coat, such as martensitic transformation and the change from β- to γ′-grains, are considered. The numerical simulations show that when the mismatch is large enough to cause overall yielding in the bond-coat, the thermal expansion of the substrate (the superalloy) will …
On The Microstructural Development In Platinum-Modified Nickel-Aluminide Bond Coats, S. Darzens, Anette M. Karlsson
On The Microstructural Development In Platinum-Modified Nickel-Aluminide Bond Coats, S. Darzens, Anette M. Karlsson
Mechanical Engineering Faculty Publications
A numerical procedure for simulating the distortions exhibited by a thermally grown oxide (TGO) upon temperature cycling has been adapted to incorporate the microstructure of the bond coat. The focus is on the dual phase β/γ′ microstructure that develops upon oxidation of a system with a Pt-aluminide bond coat. The results reveal that the presence of the γ′-phase next to the TGO reduces its distortion locally, because of the superior high-temperature strength of γ′, relative to β. Conversely, in regions where the β-phase exists adjacent to the TGO, it distorts and the TGO propagates downward, while simultaneously lengthening. These results …