Evolution of oxides and their microstructures at 800 degrees C in a gamma-gamma ` stabilised Co-Ni-Al-Mo-Ta superalloy

Das, Saurabh Mohan and Singh, Mahander Pratap and Chattopadhyay, Kamanio (2019) Evolution of oxides and their microstructures at 800 degrees C in a gamma-gamma ` stabilised Co-Ni-Al-Mo-Ta superalloy. In: CORROSION SCIENCE, 155 . pp. 46-54.

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Abstract

The paper reports mechanism of high temperature oxidation of the new gamma'-strengthened Co-30Ni-10Al-5Mo-2Ta (at%) alloy. The plots of mass gain vs. time show a parabolic growth behaviour at a temperature range of 650-800 degrees C. The cross-sections of the oxidised samples reveal formation of a complex multilayer of oxides. The top layer comprises of Co3O4 followed by a solid solution of (Co1-xNix)O (x varying from 0-0.2). A middle layer evolves with time comprising hexagonal molybdate Co2Mo3O8, metastable TaO and amorphous Al2O3. The gamma' dissolve near the interface exposing the gamma solid solution with growth of amorphous Al2O3 along the grain boundary.

Item Type:	Journal Article
Publication:	CORROSION SCIENCE
Publisher:	PERGAMON-ELSEVIER SCIENCE LTD
Additional Information:	copyright of this article belongs to PERGAMON-ELSEVIER SCIENCE LTD
Keywords:	gamma-gamma ` Cobalt based superalloys; Oxidation; Multi oxide layers; STEM
Department/Centre:	Division of Interdisciplinary Sciences > Interdisciplinary Centre for Energy Research Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	02 Jul 2019 06:27
Last Modified:	02 Jul 2019 06:27
URI:	http://eprints.iisc.ac.in/id/eprint/63110

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