Microstructural evolution of cold-sprayed Inconel 625 superalloy coatings on low alloy steel substrate

Chaudhuri, Atanu and Raghupathy, Y and Srinivasan, Dheepa and Suwas, Satyam and Srivastava, Chandan (2017) Microstructural evolution of cold-sprayed Inconel 625 superalloy coatings on low alloy steel substrate. In: ACTA MATERIALIA, 129 . pp. 11-25.

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Abstract

This study illustrates microstructural evolution of INCONEL 625 superalloy coatings cold-sprayed on a 4130 chrome alloy steel with medium carbon content. INCONEL 625 powder (5-25 mu m) were successfully cold sprayed without any oxidation. The comprehensive microstructure analysis of the as-sprayed coatings and of the substrate-coating interface was carried out using EBSD, TEM, and XRD. The coating microstructure at the substrate-coating interface was markedly different from the microstructure away from the interface. The coating microstructure at steel-coating interface consisted of a fine layer of small grains. The microstructure beyond this fine layer can be divided into splats, inter splat and intra splat boundaries. Both splat and splat boundaries exhibited deformation induced dislocations. Dynamic recovery of dislocations-ridden regions inside the splat was responsible for the development of sub grain structure inside a splat with both low and high angle grain boundaries. Splat-splat (inter splat) boundary consisted of a relatively high density of dislocations and shear bands as a result of adiabatic shear flow localisation. This flow instability is believed to enhance the microstructural integrity by eliminating porosity at splat-splat boundaries. Based on the microstructural analysis using electron microscopy, a plausible mechanism for the development of microstructure has been proposed in this work. Cold spray technique can thus be deployed to develop high quality coatings of commercial importance. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Item Type:	Journal Article
Publication:	ACTA MATERIALIA
Additional Information:	Copy right for this article belongs to the PERGAMON-ELSEVIER SCIENCE LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	25 May 2017 08:58
Last Modified:	25 May 2017 08:58
URI:	http://eprints.iisc.ac.in/id/eprint/57039

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