EFFECT OF POROSITY AND ALUMINA-CONTENT ON THE MECHANICAL-PROPERTIES OF COMPOCAST ALUMINUM-ALLOY ALUMINA PARTICULATE COMPOSITE

The effects of the size and volume fraction of alumina particles and of the porosity on the tensile strength of Al-4wt% Mg-alumina compocast particulate composite have been investigated. The contribution of porosity to the reduction in strength of the composite at various levels of alumina content is expressed as a linear function of porosity. The role of porosity in the engineering fracture strain, e//f, of the composite is found to increase almost linearly with the inverse of porosity above a critical level. For composites with a given level of porosity, e//f is found to increase with an increase in the alumina content of the composite.