Patent ID: 7360676

Claim:
A method of welding age-hardenable aluminum alloy to improve strength properties in a heat affected zone and a weld zone, the method comprising the steps of: (a) providing precipitation hardenable 7000 series aluminum alloy members to be welded; (b) subjecting said members to a first aging step for times and temperatures to generate GP zones and coherent η′ strengthening precipitates to provide aged members; (c) friction stir welding said aged members to provide a welded assembly having a weld zone; and (d) subjecting said welded assembly to a second aging step to reprecipitate strengthening GP zones and coherent η′ precipitates dissolved in the weld zone during the welding step, the second aging step being in the range of 100°-300° F. for 0.25 to 24 hours.