Hot compaction and extrusion of l12 aluminum alloys

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, consolidated by vacuum hot pressing, and extruded into useful shapes.

1 . A method for forming a high strength aluminum alloy billet containing L1 2  dispersoids, comprising the steps of:
 placing in a container a quantity of an aluminum alloy powder containing L1 2  dispersoids comprising 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; 
   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. (148.9° C.) to about 900° F. (482.2° 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. (148.9° C.) to about 900° F. (482.2° 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   extruding the billet into a useful part.   
     
     
         2 . The method of  claim 1 , wherein the degassing includes rotating or vibrating the aluminum alloy powder to heat and expose all the powder to vacuum. 
     
     
         3 . The method of  claim 1 , wherein the vacuum hot pressing comprises blind die forging or blind die compaction. 
     
     
         4 . The method of  claim 3 , wherein the blind die forging or blind die compaction is carried out at a temperature of from about 400° F. (204.4° C.) to about 1100° F. (593.3° C.). 
     
     
         5 . The method of  claim 1 , wherein the extruding is carried out at a temperature of from about 300° F. (148.9° C.) to about 900° F. (482.2° C.), at a speed of from about 0.1 inch per minute to about 20 inch per minute, and at a stress of about 10 ksi to about 100 ksi at the temperature. 
     
     
         6 . The method of  claim 1 , wherein the aluminum alloy powder contains at least one third element selected from the group consisting of silicon, magnesium, manganese, lithium, copper, zinc, and nickel. 
     
     
         7 . The method of  claim 6 , 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 0.1 to about 3 weight percent manganese, 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. 
     
     
         8 . A high strength aluminum alloy billet formed by the method of  claim 1 . 
     
     
         9 . Apparatus for forming a high strength aluminum alloy billet containing L1 2  dispersoids, comprising:
 a container for holding a quantity of an aluminum alloy powder containing L1 2  dispersoids comprising 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, the alloy powder 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 hydraulic forge or extrusion machine for blind die forging or blind die compacting the container into a billet; and   means for extruding the billet into a useful part.   
     
     
         10 . The apparatus of  claim 9 , wherein the blind die forging or blind die compaction is carried out at a temperature of from about 400° F. (204.4° C.) to about 1100° F. (593.3° C.) and a strain rate of about 0.1 inch per minute to about 20 inch per minute. 
     
     
         11 . The apparatus of  claim 9 , wherein the extruding means operates to form the useful part at a temperature of from about 300° F. (148.9° C.) to about 900° F. (482.2° C.), at a speed from about 0.1 inch per minute to about 20 inch per minute, and at a stress of about 10 ksi to about 100 ksi at extrusion temperature. 
     
     
         12 . The apparatus of  claim 9 , wherein the degassing includes rotating the aluminum alloy powder to heat and exposing to vacuum all the powder. 
     
     
         13 . The apparatus of  claim 9 , wherein the extruded part is heat treated following forming. 
     
     
         14 . The apparatus of  claim 9 , wherein the heat treat is a solution heat, quench and age. 
     
     
         15 . The apparatus of  claim 9 , wherein the aluminum alloy powder contains at least one third element selected from the group consisting of silicon, magnesium, manganese, lithium, copper, zinc, and nickel. 
     
     
         16 . The apparatus of  claim 15 , 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 0.1 to about 3 weight percent manganese, 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. 
     
     
         17 . A high strength aluminum alloy billet containing L1 2  dispersoids formed into a useful part using the apparatus of  claim 9  by extrusion. 
     
     
         18 . A method for forming a high strength aluminum alloy billet containing L1 2  dispersoids, comprising the steps of:
 placing in a container a quantity of an aluminum alloy powder containing L1 2  dispersoids comprising 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; 
   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. (148.9° C.) to about 900° F. (482.2° C.), for about 0.5 hours to about 8 days while rotating or vibrating the powder to expose all the powder to the vacuum;   sealing the degassed powder in the container under vacuum;   heating the sealed container at about 300° F. (148.9° C.) to about 900° F. (482.2° C.), for about 15 minutes to eight hours;   vacuum hot pressing the heated container by blind die forging or blind die compaction at a temperature of from about 400° F. (204.4° C.) to about 1100° F. (593.3° C.) to form a billet;   removing the container from the formed billet; and   extruding the billet into a useful part at a temperature of from about 300° F. (148.9° C.) to about 900° F. (482.2° C.), at a speed of from about 0.1 inch per minute to about 20 inch per minute, and at a stress of about 10 ksi to about 100 ksi at the temperature.   
     
     
         19 . The method of  claim 18 , wherein the aluminum alloy powder contains at least one third element selected from the group consisting of silicon, magnesium, manganese, lithium, copper, zinc, and nickel. 
     
     
         20 . The method of  claim 19 , 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 0.1 to about 3 weight percent manganese, 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.