An approach for increase of reinforcement content in particle rich zone of centrifugally cast SiC _P /Al composites

Abstract

A cylindrical ingot was produced by means of centrifugal casting using 20 vol.% SiC p /Al composite melt. The melt which was fabricated by double stir-casting method, consisting of three different sizes of SiC particles. SiC p /Al composites were characterized by optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD) techniques. The results showed that SiC particles in the 20 vol.% SiC p /Al composite melt migrated towards the outer periphery of the cylindrical ingot under centrifugal force. High reinforcement content SiC p /Al composites were obtained in a zone near the outer periphery of the cylindrical ingot, and the volume fraction of SiC particles reached up to 55%. The thermal expansion test was performed, and the coefficient of thermal expansion (CTE) of the 55 vol.% SiC p /Al composites was found to be 9.9 × 10 −6 /°C, which was lower than the predicted value based on Kerner’s model and that of 60 vol.% SiC p /Al composites fabricated by conventional processing techniques. This article presented an approach for producing high reinforcement content SiC p /Al composites.