Hot extrusion and its effect on microstructure and properties of squeeze casting SiCp/Al composites with lower volume fraction of reinforcement

Deformable SiCp/Al composites with lower volume fractions (15%, 20%, 25%) of the Sic particle reinforcement were fabricated by a squeeze casting technique. The volume fraction of the Sic particle was controlled by adding aluminum powder into the preform. The deformability of the SiCp/Al composites was studied by hot extrusion and the effect of the hot extrusion on microstructure and properties of the composites was investigated. The results show that the SiCp/Al composites fabricated by the modified squeeze casting method used here could be extruded successfully by the extrusion ratios of 9:1, 16:1, 25:1, 36: 1, respectively. The strength, modulus and tensile elongation of the composites were improved by the hot extrusion. The resulting microstructure of the composites in both as cast and extrusion states was observed and analyzed by using SEM and TEM.