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Growth mechanism of the interdiffusion zone between platinum modified bond coats and single crystal superalloys

Kiruthika, P and Makineni, SK and Srivastava, C and Chattopadhyay, K and Paul, A (2016) Growth mechanism of the interdiffusion zone between platinum modified bond coats and single crystal superalloys. In: ACTA MATERIALIA, 105 . pp. 438-448.

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Official URL: http://dx.doi.org/10.1016/j.actamat.2015.12.014

Abstract

Pt-modified beta-NiAl bond coats are applied over the superalloys for oxidation protection in jet engine applications. However, as shown in this study, it also enhances the growth of the interdiffusion zone developed between the bond coat and the superalloy along with brittle precipitates. Location of the Kirkendall plane indicates that a precipitate free sublayer grows from the bond coat, whereas another sublayer grows from the superalloy containing very high volume fraction of precipitates. With increasing Pt content, thickness of both the sublayers increases because of an increase in diffusion rates of the components. Quantitative electron probe microanalysis indicates high concentration of refractory components in the precipitates. Transmission electron microscopy shows that Rene N5 superalloy produces TCP phases mu and P, whereas CMSX-4 superalloy produces mu and sigma in the interdiffusion zone. With increasing Pt content in the bond coat, the average size of the precipitates decreases when coupled with Rene N5. Precipitates become much finer when the same bond coats are coupled with CMSX-4. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Item Type: Journal Article
Additional Information: Copy right for this article belongs to the PERGAMON-ELSEVIER SCIENCE LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND
Keywords: Nickel-based single crystal superalloys; Intermetallics (iron-aluminides); Precipitate; Diffusion mechanism; TEM
Department/Centre: Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Depositing User: Id for Latest eprints
Date Deposited: 22 Mar 2016 04:59
Last Modified: 22 Mar 2016 04:59
URI: http://eprints.iisc.ac.in/id/eprint/53395

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