Microstructure and mechanical properties of Al-Cu-Mg alloy matrix hybrid composites fabricated by squeeze casting

Hybrid composites in which Al2O3 particles were distributed among Al2O3 continuous fibres were fabricated by squeeze casting, using Al-Cu-Mg alloy as the matrix. Their microstructures and mechanical properties were investigated, with special attention paid to the effect of the presence of the Al2O3 particles. The particles were found to minimise contraction of the preform as well as the resultant fibre-to-fibre contact caused by compression. There were few reactions at the interface between the fibres and the matrix. The tensile strength parallel to the fibre axis increased as the volume fraction of the fibres increased, and was further improved by the introduction of the particles. The tensile strength of the hybrid composite perpendicular to the fibre axis was about the same as that of the unreinforced alloy, while that of the composite without particles decreased as the volume fraction of the fibres increased. Tensile fractures perpendicular to the fibre axis occurred mainly at the interface in composites without particles, but occurred in the matrix in the hybrid composites.