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  Diffusion, defects and understanding the growth of a multicomponent interdiffusion zone between Pt-modified B2 NiAl bond coat and single crystal superalloy

Esakkiraja, N., Gupta, A., Jayaram, V., Hickel, T., Divinski, S. V., & Paul, A. (2020). Diffusion, defects and understanding the growth of a multicomponent interdiffusion zone between Pt-modified B2 NiAl bond coat and single crystal superalloy. Acta Materialia, 195, 35-49. doi:10.1016/j.actamat.2020.04.016.

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Esakkiraja, Neelamegan1, Author
Gupta, Ankit2, Author              
Jayaram, Vikram3, Author              
Hickel, Tilmann2, Author              
Divinski, Sergiy V.4, 5, Author              
Paul, Aloke1, Author              
1Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, India, ou_persistent22              
2Computational Phase Studies, Computational Materials Design, Max-Planck-Institut für Eisenforschung GmbH, Max Planck Society, ou_1863341              
3Materials Engineering Department, Indian Institute of Science, Bangalore, India, ou_persistent22              
4Samara National Research University, Moskovskoye Shosse 34, Samara 443086, Russia, ou_persistent22              
5Institute for Materials Physics, University of Münster, Münster, Germany, ou_persistent22              


Free keywords: Diffusion; Defects; Multicomponent systems; TEM
 Abstract: Composition-dependent diffusion coefficients are determined in B2-Ni(CoPt)Al system following the pseudobinary and pseudo-ternary diffusion couple methods, which would not be possible otherwise in a quaternary inhomogeneous material fulfilling the conditions to solve the equations developed based on the Onsager formalism. The end-member compositions to produce ideal/near-ideal diffusion profiles are chosen based on thermodynamic details. The pseudo-binary interdiffusion coefficients of Ni and Al decrease in the presence of Co but increase in the presence of Pt. The pseudo-ternary interdiffusion coefficients indicate that the main interdiffusion coefficients increase significantly in the presence of Pt. Marginal changes of the cross interdiffusion coefficients substantiate a minor change of the diffusional interactions between the components. The thermodynamic driving forces show opposite trends with respect to composition as compared to the changes of the interdiffusion coefficients advocating a dominating role of the Pt(Co)-induced modifications of point defect concentrations. DFT-based calculations revealed that Pt alloying increases the Ni vacancy concentration and decreases the activation energy for the triple defect diffusion mechanism. These findings explain the increase in the thickness of the interdiffusion zone between the B2-Ni(Pt)Al bond coat and the single crystal superalloy Rene N5 because of Pt addition. Furthermore, the EPMA and TEM analyses reveal the growth of refractory elements-enriched precipitates. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.


Language(s): eng - English
 Dates: 2020-05-212020-08-15
 Publication Status: Published in print
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Type: Peer
 Identifiers: DOI: 10.1016/j.actamat.2020.04.016
 Degree: -



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Project name : We would like to acknowledge the financial support from ARDB, India, Grant number: ARDB/GTMAP/01/2031786/M. S.V.D. acknowledges the financial support for Brahm Prakash Visiting Chair position in IISc Bangalore during which this collaboration work was established. Partial financial support of the German Research Foundation (DFG), project number DI 1419/11-1 is also acknowledged.
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Source 1

Title: Acta Materialia
  Abbreviation : Acta Mater.
Source Genre: Journal
Publ. Info: Kidlington : Elsevier Science
Pages: - Volume / Issue: 195 Sequence Number: - Start / End Page: 35 - 49 Identifier: ISSN: 1359-6454
CoNE: https://pure.mpg.de/cone/journals/resource/954928603100