Aluminum alloy for engine components
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.