Effect of zircon and aluminum dross on sinterability and properties Al-matrix composites

In the present study, Al-matrix composites reinforced by zircon and aluminum dross were prepared by powder metallurgy after sintering at 500oC. The effect of different percentages of zircon i.e. 2, 4, 6, 8 and 10 wt. %, and aluminum dross i.e. 5, 10, 15, and 20 wt. %, on the physical properties (apparent porosity and bulk density), microstructure and microhardness were investigated in details. The apparent porosity and bulk density were determined by water displacement method according to Archimedes rule, while the microstructure was investigated by scanning electron microscope. The Microhardness was measured by Vickers tester. The results showed that the physical properties and microstructure were improved after increasing the amount of added zircon or aluminum dross. Moreover, the hardness of sintered composites was increased with increasing both zircon and aluminum dross. The hardness of zircon containing composites was lower than the hardness of aluminum dross containing composites. The maximum hardness values were obtained for Al/10% zircon (472 MPa) and Al/20% aluminum dross (532 MPa).