Low cost manufacturing of aluminium-alumina composites

Abstract

Co-continuous alumina–aluminium composite materials with excellent physical and mechanical properties offer great potentials for lightweight, wear-resistant and high-temperature applications. They combine metallic properties of matrix alloys (ductility and toughness) with ceramic properties of reinforcements (high strength and high modulus), leading to greater strength in shear and compression and higher service temperature capabilities. Composite materials prepared from a liquid-phase displacement reaction present a unique microstructure in which each phase is a continuous network penetrated by the network of the other constituent. In this study, aluminium–alumina matrix composites reinforced with glass bubbles with low thermal and electrical conductivities are presented. Different characterisation techniques were used to determine physical–mechanical properties. Porosity and density measurements were carried out by means of helium gas pycnometer and basic materials parameters were compared such as effect of the sintering process, thermal conductivity and percentage of the wax. Drop weigh tests, semi-static compression tests and also scratch tests were applied to measure the general mechanical and damage behaviour of these composites. Microstructural and fracture behaviour were evaluated by scanning electron microscopy.