Enhanced properties of alumina-aluminium titanate composites obtained by spark plasma reaction-sintering of slip cast green bodies

Abstract

Full dense alumina + 40 vol.% aluminium titanate composites were obtained by colloidal filtration and fast reaction-sintering of alumina/titania green bodies by spark plasma sintering at low temperatures (1250-1400 degrees C). The composites obtained had near-to-theoretical density (> 99%) with a bimodal grain size distribution. Phase development analysis demonstrated that aluminium titanate has already formed at 1300 degrees C. The mechanical properties such as Vickers hardness, flexural strength and fracture toughness of bulk composites are significantly higher than those reported elsewhere, e.g. the composite sintered at 1350 degrees C show values of about 24 GPa, 424 MPa and 5.4 MPa m(1/2), respectively. The improved mechanical properties of these composites are attributed to the enhanced densification and the finer and more uniform nanostructure achieved by non-conventional fast sintering of slip-cast dense green compacts. Crown Copyright (c) 2012 Published by Elsevier Ltd. All rights reserved.