Method and process of non-isothermal aging for aluminum alloys

Abstract

An improved non-isothermal aging process for aluminum alloys is disclosed. The non-isothermal aging process enhances the aging process for 7000 series aluminum alloys. In particular embodiments, the process involves continuous heating increasing at a linear rate of about 25° F. for about 11 hours and maintains high strength and corrosion properties. In an exemplary embodiment, a 7085 aluminum alloy containing 6 to 10 wt. % zinc; 1.2 to 1.9 wt. % magnesium; 1.2 to 2.2 wt. % copper, with magnesium begin less than of equal to the weight % of copper plus 0.3%; and 0.05 to 0.4 wt. % zirconium, the balance aluminum, incidental elements and impurities is aged.

1 . A process for aging an precipitation hardenable alloy comprising continuously heating the alloy at a continuous rate of increasing temperatures a time sufficient to age the alloy.  
   
   
       2 . The process of  claim 1 , wherein the precipitation hardenable alloy is a 7000 series aluminum alloy.  
   
   
       3 . The process of  claim 1 , wherein the need for a pre-aging step is eliminated.  
   
   
       4 . The process of  claim 2 , wherein the aluminum alloy comprises about 6 to 10 wt. % zinc; 1.2 to  1 . 9  wt. % magnesium; 1.2 to 2.2 wt. % copper, with magnesium begin less than or equal to the weight % of copper and 0.05 to 0.4 wt. % zirconium, the balance aluminum, incidental elements and impurities.  
   
   
       5 . The process of  claim 1 , wherein the aluminum alloy exhibits a yield strength of 54 ksi after the aging process is completed.  
   
   
       6 . The process of  claim 1  wherein the continuous rate is increased linearly.  
   
   
       7 . A process for aging an aluminum alloy containing alloying amounts of zinc, magnesium, and copper comprising continuously heating the alloy at a continuous rate less than about 25° F. per hour for about 8-15 hours.  
   
   
       8 . The process of  claim 6 , wherein the aluminum alloy is a 7000 series alloy.  
   
   
       9 . The process of  claim 6 , wherein the need for a pre-aging step is eliminated.  
   
   
       10 . The process of  claim 6 , wherein the aluminum alloy comprises about 6 to 10 wt. % zinc; 1.2 to 1.9 wt. % magnesium; 1.2 to 2.2 wt. % copper, with magnesium begin less than or equal to the weight % of copper and 0.05 to 0.4 wt. % zirconium, the balance aluminum, incidental elements and impurities.  
   
   
       11 . The process of  claim 6 , wherein the aluminum alloy exhibits a yield strength of 54 ksi after the aging process is completed.  
   
   
       12 . A process for aging an aluminum alloy containing alloying amounts of zinc, magnesium, and copper comprising continuously heating the alloy at a continuous rate of less than about 25° F. per hour for about 11 hours.  
   
   
       13 . The process of  claim 11 , wherein the aluminum alloy is a 7000 series alloy.  
   
   
       14 . The process of  claim 11 , wherein the need for a pre-aging step is eliminated.  
   
   
       15 . The process of  claim 11 , wherein the aluminum alloy comprises about 6 to 10 wt. % zinc; 1.2 to 1.9 wt. % magnesium; 1.2 to 2.2 wt. % copper, with magnesium begin less than or equal to the weight % of copper and 0.05 to 0.4 wt. % zirconium, the balance aluminum, incidental elements and impurities.  
   
   
       16 . The process of  claim 11 , wherein the aluminum alloy exhibits a yield strength of 54 ksi after the aging process is completed.