The production of AlN-rich matrix composites by the reactive infiltration of Al alloys in nitrogen

Swaminathan, S and Rao, Srinivasa B and Jayaram, V (2002) The production of AlN-rich matrix composites by the reactive infiltration of Al alloys in nitrogen. In: Acta Materialia, 50 (12). pp. 3093-3104.

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Abstract

Aluminium nitride (AlN)-Al matrices reinforced with Al2O3 particulate have been fabricated by reactive infiltration of Al-2% Mg alloy into Al2O3 preforms in N-2 in the temperature range of 900-1075 degreesC. The growth of composites of useful thickness was facilitated by the presence of a Mg-rich external getter, in the absence of which composite growth is self-limiting and terminates prematurely. Successful growth of composites has been attributed to the reduction in residual oxygen partial pressure brought about by the reaction with oxygen of highly volatile Mg in the getter alloy. The microstructure of the matrix consists of AlN-rich regions contiguous with the particulate with metal-rich channels in-between, thereby suggesting that nitridation initiates by preferential wicking of alloy along the particle surfaces. The increase in nitride content of the matrix with temperature is consistent with hardness values that vary between similar to3 and 10 GPa. (C) 2002 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.

Item Type:	Journal Article
Publication:	Acta Materialia
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	AlN-rich matrix;Infiltration;External getter;Nitridation
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	27 Jul 2011 06:55
Last Modified:	27 Jul 2011 06:55
URI:	http://eprints.iisc.ac.in/id/eprint/39482

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