HIGH PERFORMANCE AlSiMgCu CASTING ALLOY

Abstract

An aluminum casting alloy has 8.5-9.5 wt. % silicon, 0.5-2.0 wt. % copper (Cu), 0.27-0.53 wt. % magnesium (Mg), wherein the aluminum casting alloy includes copper and magnesium such that 4.7≦(Cu+10Mg)≦5.8, and other elements, the balance being aluminum. Selected elements may be added to the base composition to give resistance to degradation of tensile properties due to exposure to heat. The thermal treatment of the alloy is calculated based upon wt. % composition to solutionize unwanted phases having a negative impact on properties and may include a three level ramp-up and soak to a final temperature followed by cold water quenching and artificial aging.

We claim: 
     
         1 . An aluminum casting alloy consisting of:
 8.5-9.5 wt. % silicon;   0.5-2.0 wt. % copper (Cu);   0.27-0.53 wt. % magnesium (Mg);
 wherein the aluminum casting alloy includes copper and magnesium such that 4.7≦(Cu+10Mg)≦5.8; 
   up to 5.0 wt. % zinc;   up to 1.0 wt. % silver;   up to 1.0 wt. % nickel   up to 1.0 wt. % hafnium   up to 1.0 wt. % manganese   up to 1.0 wt. % iron;   up to 0.30 wt. % titanium;   up to 0.30 wt. % zirconium;   up to 0.30 wt. % vanadium;   up to 0.10 wt. % of one or more of strontium, sodium and antimony;   other elements being ≦0.04 wt. % each and ≦0.12 wt. % in total;   the balance being aluminum.