Aluminum alloy for engine components

Abstract

A castable aluminum alloy includes, in weight %, about 0.4% to about 2.5% Si, up to about 5% Cu, up to about 1% Mg, up to about 1% Fe, up to about 2% Mn, up to about 0.3% Ti, up to about 2.5% Ni, up to about 3% Zn, and the balance aluminum and provides reduced casting porosity and improved tensile strength and ductility in the cast and the heat treated condition.

1 . An aluminum casting alloy consisting essentially of, in weight %, about 0.4% to about 2.5% Si, up to about 5% Cu, up to about 1% Mg, up to about 1% Fe, up to about 2% Mn, up to about 0.3% Ti, up to about 2.5% Ni, up to about 3% Zn, and the balance aluminum. 
     
     
         2 . The alloy of  claim 1  having a ratio of Mn/Fe in the range of 0.6 to 1.8 when the Fe concentration of the alloy is greater than about 0.3% by weight. 
     
     
         3 . The alloy of  claim 1  wherein the Si concentration is controlled to provide a cast microstructure that is substantially free of eutectic silicon phase. 
     
     
         4 . The alloy of  claim 1  further including up to about 0.03% Sr by weight. 
     
     
         5 . The alloy of  claim 1  wherein Cu is about 1% to about 4% by weight. 
     
     
         6 . An aluminum casting alloy consisting essentially of, in weight %, about 0.8% to about 2.5% Si, about 1.5% to about 2.5% Cu, about 0.1% to about 0.5% Mg, about 0.3% to about 0.6% Fe, about 0.4% to about 0.8% Mn, about 0.04% to about 0.2% Ti, up to about 2.5% Ni, up to about 1% Zn, and the balance aluminum. 
     
     
         7 . The alloy of  claim 6  having a Si content of about 0.8% to about 1.5% by weight. 
     
     
         8 . The alloy of  claim 7  having a Si content of about 1.0% to about 1.4% by weight. 
     
     
         9 . The alloy of  claim 6  having a ratio of Mn/Fe in the range of 0.6 to 1.8 when the Fe concentration of the alloy is greater than about 0.3% by weight. 
     
     
         10 . An aluminum casting alloy consisting essentially of, in weight %, about 0.8% to about 2.5% Si, about 3.0% to about 4.0% Cu, about 0.1% to about 0.5% Mg, about 0.3% to about 0.6% Fe, about 0.4% to about 0.8% Mn, about 0.04% to about 0.2% Ti, up to about 2.5% Ni, up to about 1% Zn, about 0.008% to about 0.02% Sr, and the balance aluminum. 
     
     
         11 . The alloy of  claim 10  having a Si content of about 0.8% to about 1.5% by weight. 
     
     
         12 . The alloy of  claim 11  having a Si content of about 1.0% to about 1.4% by weight. 
     
     
         13 . The alloy of  claim 10  having a ratio of Mn/Fe in the range of 0.6 to 1.8 when the Fe concentration of the alloy is greater than about 0.3% by weight. 
     
     
         14 . A cast article comprising an aluminum alloy consisting essentially of, in weight %, about 0.4% to about 2.5% Si, up to about 5% Cu, up to about 1% Mg, up to about 1% Fe, up to about 2% Mn, up to about 0.3% Ti, up to about 2.5% Ni, up to about 3% Zn, and the balance aluminum. 
     
     
         15 . The article of  claim 14  wherein the aluminum alloy has a ratio of Mn/Fe in the range of 0.6 to 1.8 when the Fe concentration of the alloy is greater than about 0.3% by weight. 
     
     
         16 . The article of  claim 14  wherein the alloy includes about 1% to about 4% Cu by weight. 
     
     
         17 . The article of  claim 14  wherein the alloy further includes up to about 0.03% Sr by weight. 
     
     
         18 . The article of  claim 14  which is precipitation hardened. 
     
     
         19 . A method of making a casting, comprising melting a castable aluminum alloy consisting essentially of, in weight %, about 0.4% to about 2.5% Si, up to about 5% Cu, up to about 1% Mg, up to about 1% Fe, up to about 2% Mn, up to about 0.3% Ti, up to about 2.5% Ni, up to about 3% Zn, and the balance aluminum, introducing the melted alloy into a mold, and solidifying the melted alloy in the mold to form a casting. 
     
     
         20 . The method of  claim 19  wherein the alloy includes Si from about 0.8% to about 1.5% by weight. 
     
     
         21 . The method of  claim 19  wherein the Si content of the alloy is about 1.0% to 1.4% by weight. 
     
     
         22 . The method of  claim 19  wherein the alloy includes about 1% to about 4% Cu by weight. 
     
     
         23 . The method of  claim 19  including the further step of heating the casting to a solution temperature. 
     
     
         24 . The method of  claim 23  including the further step of cooling the casting from the solution temperature and aging the casting to precipitation harden it.