Development of Hybrid Magnesium-based Composites

Metal matrix composites have widely been recognized to possess superior mechanical properties at both room and elevated temperatures, such as high elastic modulus and strengths as well as enhanced wear resistance, compared to the unreinforced monolithic metal. In this study, a novel approach of making hybrid preforms with two or more types of reinforcements, i.e., low-cost and different sized particles and fibres, for magnesium-based composites was developed. An advanced and affordable technique of fabricating hybrid magnesium based composites named the preform-squeeze casting was employed successfully. The microstructural analyses show that both the particles and fibres distribute homogeneously in the preform and its matrix materials of the composites. The grain refinement mechanisms of the hybrid composites during solidification were investigated. The engineering performance of the composites was evaluated by tensile testing in comparison with the matrix alloy. The tensile testing results indicate that the tensile properties of the hybrid composites with (4vol%Al2O3 particles + 9vol%Al2O 3 fibres) are considerably improved over those of the matrix magnesium alloy.