Growth of $Al_2O_3/Al$ Composites from Al-Zn Alloys

Hanabe, Murali and Jayaram, Vikram and Bhaskaran, TA (1996) Growth of $Al_2O_3/Al$ Composites from Al-Zn Alloys. In: Acta Materialia, 44 (2). pp. 819-829.

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Abstract

Observations are presented here of the initiation and growth of an $Al_2O_3/Al$ composite by the directed oxidation of a molten binary Al-Zn alloy with and without preforms. The oxidation behaviour into free space begins with the formation of ZnO on the melt surface followed by a second stage of relatively high growth rate associated with the constant presence of ZnO and a final region of slow growth rate during which the surface consists of both ZnO as well as $Al_2O_3$. Composite formation is explained on the basis of a cyclic formation and reduction by molten aluminium of ZnO. Oxidation was carried out with ternary Mg additions into $Al_2O_3$ preforms of different particle sizes. The infiltration of an $Al_2O_3$ preform is governed by reaction induced wetting between alloy and ZnO. Nucleation of the alumina is epitaxial with respect to particles of the preform and growth rates are higher than that for composite growth into free space.

Item Type:	Journal Article
Publication:	Acta Materialia
Publisher:	Elsevier
Additional Information:	Copyright of this article belongs to Elsevier.
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	27 Dec 2006
Last Modified:	19 Sep 2010 04:33
URI:	http://eprints.iisc.ac.in/id/eprint/9136

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