Effect of the hydrostatic extrusion on the properties of extruded Al and Al/SiCp

This work is entitled to study the effect of hydrostatic extrusion, for different extrusion ratios on the mechanical properties of the extruded Al and Al/SiCP composites. An experimental hydrostatic extrusion device is designed and constructed for that purpose. Billets of Al and Al-SiCp composites with initial diameters of 15 and 20mm and with length of 50 mm are used. Reduction ratios of 43%, 55%, and 75% are performed. The mean extrusion pressure, tensile stress, microstructure and hardness of commercially pure aluminum extrudate are evaluated, as well as, for Al-SiC composites. Microstructure has significant changes after hydrostatic extrusion. The large grains with grain size 600 μm have refined after hydrostatic extrusion for pure Al, Fine precipitate in the direction of extrusion was recognize for Al/SiCP. It is also found that the extrusion improves the mechanical properties of pure Al and Al/SiCP in terms of the tensile strength and hardness. An apparent work hardening behavior was observed in the extrudate, the improvement of mechanical properties is mainly attributed to the fine grain strengthening effects. No cracks for Al/SiCP were observed after hydrostatic extrusion in comparison to conventional method, better surface quality was obtained.