Method for forming high strength aluminum alloys containing L12 intermetallic dispersoids

Abstract

A method and apparatus produces high strength aluminum alloys from a powder containing L1 2 intermetallic dispersoids. The powder is degassed, sealed under vacuum in a container, heated, consolidated by vacuum hot pressing, and extruded.

1 . A method for producing a high strength aluminum alloy billet containing L1 2  dispersoids, comprising the steps of:
 placing a quantity of an aluminum alloy powder containing an L1 2  dispersoid therein 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; and   removing the container from the formed billet.   
     
     
         2 . The method of  claim 1 , wherein the container is aluminum having a configuration with a central axis, and vacuum hot pressing is done along the axis while restraining radial movement of the container. 
     
     
         3 . The method of  claim 1 , wherein the vacuum hot pressing includes blind die compaction for about 1 minute to about 8 hours at a temperature of 300° F. (149° C.) to about 900° F. (482° C.) under uni-axial pressure of about 5 ksi to about 100 ksi. 
     
     
         4 . The method of  claim 1 , wherein the vacuum hot pressing produces a billet of the aluminum alloy powder having a density of about 100 percent. 
     
     
         5 . The method of  claim 1 , wherein the degassing includes rotating the aluminum alloy powder to heat and expose all the powder to vacuum. 
     
     
         6 . The method of  claim 1 , wherein the thus formed billet is extruded at a load of about 100 tons to about 10,000 tons. 
     
     
         7 . The method of  claim 6 , wherein the extrusion temperature is about 300° F. (149° C.) to about 900° F. (482° C.), the billet soak time is about 15 minutes to about 8 hours at a rate of about 0.2 inch per minute to about 20 inches per minute and an extrusion ratio of about 2:1 to about 500:1. 
     
     
         8 . The method of  claim 1 , wherein the L1 2  dispersoids comprise Al 3 X dispersoids wherein X is at least one first element selected from the group comprising:
 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 comprising 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.   
     
     
         9 . The method of  claim 8 , wherein the aluminum alloy powder contains at least one third element selected from the group consisting of silicon, magnesium, lithium, copper, zinc, and nickel. 
     
     
         10 . The method of  claim 9 , wherein the third element comprises at least one of about 4 to about 25 weight percent silicon, about 1 to about 8 weight percent magnesium, about 0.5 to about 3 weight percent lithium, about 0.2 to about 6 weight percent copper, about 3 to about 12 weight percent zinc, about 1 to about 12 weight percent nickel. 
     
     
         11 . The method of  claim 8 , wherein the L1 2  dispersoids comprise Al 3 X dispersoids wherein X is at least one first element selected from the group comprising:
 about 0.1 to about 0.5 weight percent scandium, about 0.1 to about 6.0 weight percent erbium, about 0.1 to about 10.0 weight percent thulium, about 0.1 to about 15.0 weight percent ytterbium, and about 0.1 to about 12.0 weight percent lutetium;   at least one second element selected from the group comprising about 0.1 to about 4.0 weight percent gadolinium, about 0.1 to about 4.0 weight percent yttrium, about 0.05 to about 1.0 weight percent zirconium, about 0.05 to about 2.0 weight percent titanium, about 0.05 to about 2.0 weight percent hafnium, and about 0.05 to about 1.0 weight percent niobium; and   the balance substantially aluminum.   
     
     
         12 . Apparatus for producing a high strength aluminum alloy billet containing L1 2  dispersoids, comprising:
 a container for holding a quantity of an aluminum alloy powder containing an L1 2  dispersoid therein having a mesh size of less than 450 mesh;   a vacuum and heat source for 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 means for sealing the degassed powder in the container under vacuum;   a heater for heating the sealed container at about 300° F. (149° C.) to about 900° F. (482° C.) for about 15 minutes to eight hours;   a vacuum hot press for forming the heated container into a billet; and   means for removing the container from the thus formed billet.   
     
     
         13 . The apparatus of  claim 12 , wherein the container is aluminum having a central axis, and vacuum hot pressing is done along the axis while restraining transverse movement of the container. 
     
     
         14 . The apparatus of  claim 12 , wherein the vacuum hot pressing includes blind die compaction for about 1 minute to about 8 hours at a temperature of 300° F. (149° C.) to about 900° F. (482° C.) under uni-axial pressure of about 5 ksi to about 100 ksi. 
     
     
         15 . The apparatus of  claim 12 , wherein the vacuum hot pressing produces a billet of the aluminum alloy powder having a density of about 100 percent. 
     
     
         16 . The apparatus of  claim 12 , wherein the degassing includes rotating the aluminum alloy powder to heat and exposing to vacuum all the powder. 
     
     
         17 . The apparatus of  claim 12 , wherein the formed billet is extruded at a load of about 100 tons to about 10,000 tons. 
     
     
         18 . The apparatus of  claim 17 , wherein the extrusion temperature is about 300° F. (149° C.) to about 900° F. (482° C.), the billet soak time is about 15 minutes to about 8 hours at a rate of about 0.2 inch per minute to about 20 inches per minute, and an extrusion ratio of about 2:1 to about 500:1. 
     
     
         19 . The apparatus of  claim 12 , wherein the L1 2  dispersoids comprise Al 3 X dispersoids wherein X is at least one first element selected from the group comprising:
 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 comprising 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.   
     
     
         20 . The apparatus of  claim 19 , wherein the aluminum alloy powder contains at least one third element selected from the group consisting of silicon, magnesium, lithium, copper, zinc, and nickel. 
     
     
         21 . The apparatus of  claim 20 , wherein the third element comprises at least one of about 4 to about 25 weight percent silicon, about 1 to about 8 weight percent magnesium, about 0.5 to about 3 weight percent lithium, about 0.2 to about 6 weight percent copper, about 3 to about 12 weight percent zinc, about 1 to about 12 weight percent nickel. 
     
     
         22 . The apparatus of  claim 19 , wherein the L1 2  dispersoids comprise Al 3 X dispersoids wherein X is at least one first element selected from the group comprising:
 about 0.1 to about 0.5 weight percent scandium, about 0.1 to about 6.0 weight percent erbium, about 0.1 to about 10.0 weight percent thulium, about 0.1 to about 15.0 weight percent ytterbium, and about 0.1 to about 12.0 weight percent lutetium;   at least one second element selected from the group comprising about 0.1 to about 4.0 weight percent gadolinium, about 0.1 to about 4.0 weight percent yttrium, about 0.05 to about 1.0 weight percent zirconium, about 0.05 to about 2.0 weight percent titanium, about 0.05 to about 2.0 weight percent hafnium, and about 0.05 to about 1.0 weight percent niobium; and   the balance substantially aluminum.