Mechanical characterisation of AA7015 aluminium alloy reinforced with ceramics

Manufacturing of metal matrix composites (MMCs) through powder metallurgy route and their characterisation are the objects of the present work. Thus a light alloy reinforced with 5% of ceramics is obtained after attrition milling of mixed powders, die pressing, lubrication of compacts and hot extrusion into 10 mm diameter bars. Since 7xxx series of aluminium alloys show high mechanical properties, AA7015 alloy was chosen as metallic matrix and B4C, TiB2 and Si3N4 ceramics were added. After process optimisation, the microstructure of these materials shows a uniform distribution of ceramics in the aluminium alloy matrix. Physical properties like density, conductivity and coefficient of linear dilatation were determined on extruded MMCs samples. Hardness and tensile strength properties on machined samples according to ISO 2740 standard were evaluated. Also wear behaviour using a pin-on disk test was studied, within a microstructure study, which was carried out using optical and scanning electron microscopy.