Effect of Particle Distribution on the Properties of Aluminum Matrix In-situ Particulate Composites

Abstract

Discontinuously reinforced aluminum matrix composites are fast emerging materials that compete with conventional metallic materials. In-situ particulate composites in comparison with conventional cast particulate composites produced by external addition, promote cleaner interfaces, eliminate interface incompatibility of the matrices with the reinforcements, help to achieve greater thermodynamic stability of reinforcement particles in the matrix at elevated temperature, and also increase the possibility of developing coherency between the matrix and particles formed in-situ. The morphology and the distribution of particles strongly influence the physical and mechanical properties of the composites. In the present study, ilmenite was added to molten aluminum, aluminum—magnesium and aluminum—silicon alloys by vortex method. The oxides present in ilmenite are observed to react with aluminum, magnesium and resulting in production of Al2O 3, MgO and metallic Fe and Ti, which dissolved in liquid aluminum. The strength and hardness value showed considerable improvement. The resulting composites also show appreciable ductility. It is shown that aluminum matrix in-situ particulate composites can be successfully produced with the addition of ilmenite through the casting route in the existing foundries with very little modification.