Title: Effect of alumina inclusions on microstructure and mechanical properties of 62 WC, 32 (Ti-W) C and 6 Co compacts

Authors: Mushtaq Albdiry; Haydar Alethari

Addresses: Department of Mechanical Engineering, University of Southern Queensland, Toowoomba, Qld, 4350, Australia. ' Department of Materials Engineering, Babylon University, Hilla-Najaf Road, Al-Hilla, Iraq

Abstract: This investigation is aimed at understanding the role of adding ceramic inclusion, alumina (Al₂O₃) on the densification, microstructure and mechanical properties of cemented carbide cutting inserts. The samples were prepared of an initial mixture of 62 WC, 32 (Ti-W) C and 6 Co wt% particulates; different additions of Al₂O₃ of 1, 2, 3 and 4 wt% were introduced to that mixture. The testing specimens were compacted via powder metallurgy at 200 MPa and sintered at 1,410°C under vacuum. The green and sintered densities have decreased; the figures of macrohardness, Vickers hardness and transverse rupture strength have also deteriorated with the increase of alumina content. The macrohardness has almost declined of 30% at 3% alumina. This is ascribed to the interfacial grain-boundary decohesion between Al₂O₃ and carbide particles as can be observed from scanning electron microscopy images which depicts the monolithic clusters in the final consolidation of the compacts.

Keywords: powder metallurgy; cemented carbide; alumina; ceramic inclusion; microstructure; materials properties; densification; cutting inserts; hardness; transverse rupture strength.

DOI: 10.1504/IJMMP.2012.048523

International Journal of Microstructure and Materials Properties, 2012 Vol.7 No.4, pp.329 - 340

Published online: 14 Aug 2012 *

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