The element aluminum (Al) has a specific gravity of 2.7, placing it among the light-weight structural metals. It is used as a base for die casting alloys with three primary constituents: silicon, copper and magnesium. Eight available aluminum die casting alloys give the designer the widest choice among the four primary alloy groups, and they account for the majority of die castings in terms of tons of components produced.  You can also learn more on NADCA's Design Website.