The effect of Al–5Ti–1B on the microstructure, hardness and tensile properties of Al2O3 and SiC-containing metal–matrix composites

The microstructure and tensile properties of two particulate metal–matrix composites have been studied in the present work. The composite ingots were made by stir casting process which had similar matrices (A356 aluminium alloy) and different volume fraction of Al2O3 and SiC particles (5, 10, 15 and 20 vol.%). It was found that increasing volume fraction of the reinforcing particles reduces tensile strength and ductility of the composites but, the addition of 4 wt.% Al–5Ti–1B to composites improves the tensile strength and elongation values to some extent. Microstructural observations and fractographic examination of the fractured faces of several cast MMCs showed that these materials basically suffer from microshrinkage pores which increase with the addition of ceramic reinforcements.