Superplastic forming high strength L12 aluminum alloys

A method for forming a high strength aluminum alloy billet containing L12 dispersoids, comprising the steps of:

• placing in a container a quantity of an aluminum alloy powder containing an L12 dispersoid L12 comprising Al3X dispersoids wherein X is at least one first element selected from the group consisting of:
• about 0.1 to about 4.0 weight percent scandium, about 0.1 to about 20.0 weight percent erbium, about 0.1 to about 15.0 weight percent thulium, about 0.1 to about 25.0 weight percent ytterbium, and about 0.1 to about 25.0 weight percent lutetium;
• at least one second element selected from the group consisting of about 0.1 to about 20.0 weight percent gadolinium, about 0.1 to about 20.0 weight percent yttrium, about 0.05 to about 4.0 weight percent zirconium, about 0.05 to about 10.0 weight percent titanium, about 0.05 to about 10.0 weight percent hafnium, and about 0.05 to about 5.0 weight percent niobium;
• and
• the balance substantially aluminum;
• the alloy powder having a mesh size of less than 450 mesh in a container, vacuum degassing the powder at a temperature of about 300° F. (149° C.) to about 900° F. (482° C.) for about 0.5 hours to about 8 days;
• sealing the degassed powder in the container under vacuum;
• heating the sealed container at about 300° F. (149° C.) to about 900° F. (482° C.) for about 15 minutes to eight hours;
• vacuum hot pressing the heated container to form a billet;
• removing the container from the formed billet;
• and
• superplastically forming the billet into a useful part, wherein superplastic forming is carried out at tensile elongation of from about 200 percent to greater than 1,000 percent without plastic instability.