Aluminum-copper-magnesium alloys having ancillary additions of lithium

Abstract

An aluminum-copper-magnesium alloy having ancillary additions of lithium. The alloy composition includes from about 3 to about 5 weight percent Cu, from about 0.5 to about 2 weight percent Mg, and from about 0.01 to about 0.9 weight percent Li. The combined amount of Cu and Mg is maintained below a solubility limit of the aluminum alloy. The alloys possess improved combinations of fracture toughness and strength, and also exhibit good fatigue crack growth resistance.

1 - 24 . (canceled) 
   
   
       25 . A wrought aluminum alloy consisting essentially of:
 3 to 4.5 wt. % Cu;   0.6 to 2 wt. % Mg;   0.01 to 0.8 wt. % Li;   optionally up to 2 wt. % Zn;   optionally up to 2 wt. % Ag;   optionally up to 2 wt. % Si;   optionally up to 1 wt. % of a dispersoid-forming element;   the balance being aluminum and incidental elements and impurities;   
     wherein the wrought aluminum alloy possesses at least one of: (i) higher fracture toughness and equivalent or higher strength in at least one temper in comparison to a similar alloy having no lithium or greater than 0.9 wt. % lithium; and (ii) higher strength and equivalent or higher fracture toughness in at least one temper in comparison to a similar alloy having no lithium or greater than 0.9 wt. % lithium.