Patent ID: 6569271
Filing Date: 2003-05-27
Classification: C22C,C22F

Abstract:
A process for thermally treating an article made from an aluminum alloy, the process comprising:providing the aluminum alloy consisting essentially of from about 5.7 to about 6.7 wt. % of zinc, less than 2.2 wt. % copper, less than 4.2 wt. % of the total weight percent of magnesium and copper combined, and less than 10.60 wt. % of the total weight percent of magnesium, copper and zinc combined, the balance being substantially aluminum, incidental elements and impurities; solid solution heat treating the article; quenching the article; heating the article to a first temperature; artificially aging the article at the first temperature; heating the article to a second temperature, wherein the second temperature is higher than the first temperature; artificially aging the article at the second temperature of from about 290 to about 360Â° F. for a duration of at least 6 hours; and cooling the article from the second temperature to 200Â° F. at a cooling rate of from about 20 to about 40Â° F./hour.