Wear-resistant aluminum alloy and compressor piston formed therefrom

A forging formed of a wear-resistant aluminum alloy consisting of the following by weight:

• 13.0 to 15.5 percent silicon;
• 0.8 to 1.8 percent copper;
• 0.8 to 1.3 percent magnesium;
• not more than 0.7 percent iron;
• not more than 0.25 percent zinc;
• not more than 0.2 percent manganese;
• not more than 0.15 percent nickel;
• not more than 0.1 percent chromium;
• not more than 0.1 percent titanium;
• phosphorus in an amount sufficient to yield silicon particles within a range of about fifteen to thirty-five micrometers in equivalent diameter;
• not more than 0.15 percent impurities, each of the impurities not exceeding 0.05 percent of the alloy;
• and
• the balance being aluminum;
• wherein the wear-resistant aluminum alloy contains a dispersion of copper-aluminide precipitates throughout.

A piston produced by a process comprising the steps of:

• casting a homogeneous melt of a wear-resistant aluminum alloy consisting of the following by weight:
• about 13.0 to about 15.5 percent silicon;
• about 0.8 to about 1.8 percent copper;
• about 0.8 to about 1.3 percent magnesium;
• not more than 0.7 percent iron;
• not more than 0.25 percent zinc;
• not more than 0.2 percent manganese;
• not more than 0.15 percent nickel;
• not more than 0.1 percent chromium;
• not more than 0.1 percent titanium;
• up to about 0.15 percent phosphorus;
• not more than 0.15 percent impurities, each of the impurities not exceeding 0.05 percent of the alloy;
• and the balance being aluminum;
• forging the wear-resistant aluminum alloy to form a piston;
• and
• solution heat treating the piston at a temperature of about 475.degree. C. to about 485.degree. C. for a duration of about two hours, during which a dispersion of copper-aluminide precipitates is formed throughout the piston, the piston further containing silicon particles within a range of about fifteen to thirty-five micrometers in equivalent diameter.