Fabrication, microstructure and mechanical properties of Mg matrix composites reinforced by high volume fraction of sphere TC4 particles

A novel liquid settling method was investigated and applied to fabricate TC4 spherical particle reinforced AZ91 alloy matrix composites. This method was called liquid state settling technique in which TC4 particles would settle down under the force of gravity. High volume fraction (50%) particle reinforced AZ91 composites could be easily obtained via this novel method. This is difficult to achieve for other traditional liquid fabrication methods. In addition, there was a good dispersion of TC4 particles in the AZ91 matrix and no clusters were found, which indicate that this method was feasible. Interfacial reaction occurred and the reaction product was confirmed to be Al₂Ti. Three kinds of pre-dispersion technologies were used before the settling process and different interfacial microstructures were found. Theoretical calculation and experimental results both indicated that the interfacial product which was embedded in the matrix strengthened the composites and improved the tensile strength.