The effect of Si and Mg on age hardening behavior of Al-SiCp composites

An investigation was carried out to determine the effect of Si and Mg on ageing behavior of Al-7%Si-0.7%Mg matrix composites reinforced with SiC particles of 10 and 20 vol.% and unreinforced matrix alloy. The samples were produced by compocasting technique and extruded. The produced samples were characterized by optical microscope, image analyzer, scanning electron microscope and X-ray mapping. The obtained results were compared with the previous study, which was studied on Al-5%Si-0.2%Mg matrix alloy and composites. It has been found that, the formation of some reaction products, mechanical properties and age hardening behavior of the composites strongly depend on Si and Mg content of the matrix alloy. In addition, increasing the Mg and Si content from 0.2 and 5 wt.% to 0.7 and 7wt.% respectively, increase the critical temperature and hardening efficiency values.