Ceracon forging of l12 aluminum alloys

Abstract

A method for producing high strength aluminum alloy consolidated billets containing L1 2 dispersoids by Ceracon forging is disclosed. The method comprises forming an aluminum alloy powder compact preform containing L1 2 dispersoid forming elements therein and encompassing the preform in a flowable pressure transmitting medium in a die in a hydraulic press. The die, pressure transmitting medium and preform are then heated and the preform is forged by applying pressure to the pressure transmitting medium by the ram of the hydraulic press. The unequal axial and radial strain resulting from this type of forging results in improved mechanical properties of L1 2 aluminum alloys.

1 . A method for producing high strength aluminum alloy consolidated billets containing L1 2  dispersoids, comprising the steps of:
 forming an aluminum alloy powder containing L1 2  dispersoid forming elements,
 wherein the L1 2  dispersoid forming elements form 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; 
 
   placing the powder in a container;   vacuum degassing the container at about 500° F. (260° C.) to about 900° F. (482° C.) for about 12 hours to about 8 days;   sealing the container;   creating a preform by compressing the container by closed die forging or by quasi-isostatic forging to consolidate the powder;   encompassing the aluminum alloy powder preform with a flowable pressure transmitting medium and heating the encompassed alloy powder; and   uniaxially compressing the medium to thereby consolidate the aluminum powder; and   removing the consolidated powder billet.   
     
     
         2 . The method of  claim 1 , wherein the forging temperature is from about 400° F. (204° C.) to about 900° F. (482° C.). 
     
     
         3 . The method of  claim 1 , wherein the axial strain rate during compressing the medium is from about 0.1 min −1  to 6 min −1 . 
     
     
         4 . The method of  claim 1 , wherein compressing the medium is at a pressure from about 50 Ksi (345 MPa) to about 150 Ksi (1034 MPa). 
     
     
         5 . The method of  claim 1 , wherein the preform is vacuum sealed in an aluminum jacket. 
     
     
         6 . The method of  claim 1  wherein the pressure transmitting medium comprises graphite or other carbon containing powders or ceramic powders or both. 
     
     
         7 . The method of  claim 1  wherein the aluminum alloy powder contains at least one third element selected from the group consisting of silicon, magnesium, lithium, copper, zinc and nickel. 
     
     
         8 . The method of  claim 1  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 6.5 weight percent copper, about 3 to about 12 weight percent zinc, and about 1 to about 12 weight percent nickel. 
     
     
         9 . A high strength aluminum alloy consolidated billet containing L1 2  dispersoids in an aluminum alloy matrix wherein:
 the L1 2  dispersoid forming elements form 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, wherein:   the aluminum alloy consolidated billet containing L1 2  dispersoids is formed by the steps comprising:   placing the powder in a container;   vacuum degassing the container at about 500° F. (260° C.) to about 900° F. (482° C.) for about 12 hours to about 8 days;   sealing the container;   creating a preform by compressing the container by closed die forging or by quasi-isostatic forging to consolidate the powder;   encompassing the aluminum alloy powder preform with a flowable pressure transmitting medium and heating the encompassed alloy powder; and   encompassing the aluminum alloy powder preform with a flowable pressure transmitting medium and heating the encompassed alloy powder and medium; and   uniaxially compressing the medium to thereby consolidate the aluminum powder; and   removing the consolidated powder billet.   
     
     
         10 . The alloy of  claim 9 , wherein the aluminum alloy powder contains at least one third element selected from the group consisting of silicon, magnesium, lithium, copper, zinc, and nickel. 
     
     
         11 . The alloy of  claim 10 , 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 6.5 weight percent copper, about 3 to about 12 weight percent zinc, and about 1 to about 12 weight percent nickel. 
     
     
         12 . The alloy of  claim 9 , wherein the forging temperature is from about 400° F. (204° C.) to about 900° F. (482° C.). 
     
     
         13 . The alloy of  claim 9 , wherein the axial strain rate during compressing the medium is from about 0.1 min −1  to 6 min −1 . 
     
     
         14 . The alloy of  claim 9 , wherein compressing the medium is at a pressure from about 50 Ksi (345 MPa) to about 150 Ksi (1034 MPa). 
     
     
         15 . The alloy of  claim 9 , wherein the pressure transmitting medium comprises graphite or other carbon containing powders or ceramic powders or both. 
     
     
         16 . A high strength aluminum alloy consolidated billet containing L1 2  dispersoids in an aluminum alloy matrix wherein:
 the L1 2  dispersoid forming elements form 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, wherein:   the aluminum alloy consolidated billet containing L1 2  dispersoids is formed by the steps comprising:   placing the powder in a container;   vacuum degassing the container at about 500° F. (260° C.) to about 900° F. (482° C.) for about 12 hours to about 8 days;   sealing the container;   creating a preform by compressing the container by closed die forging or by quasi-isostatic forging to consolidate the powder;   encompassing the aluminum alloy powder preform with a flowable pressure transmitting medium and heating the encompassed alloy powder and medium; and   uniaxially compressing the medium at an axial strain rate of from about 0.1 min −1  to about 6 min −1  at a pressure from about 50 KSi (345 MPa) to about 150 KSi (1034 MPa) to thereby consolidate the aluminum powder; and   removing the consolidated powder in a billet.   
     
     
         17 . The high strength aluminum alloy consolidated billet of  claim 16  wherein the aluminum alloy powder contains at least one third element selected from the group consisting of silicon, magnesium, lithium, copper, zinc, and nickel. 
     
     
         18 . The high strength aluminum alloy consolidated billet of  claim 16  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 6.5 weight percent copper, about 3 to about 12 weight percent zinc, and about 1 to about 12 weight percent nickel. 
     
     
         19 . The high strength aluminum alloy consolidated billet of  claim 16  wherein the forging temperature is from about 400° F. (204° C.) to about 900° F. (482° C.). 
     
     
         20 . The high strength aluminum alloy consolidated billet of  claim 16  wherein the pressure transmitting medium comprises graphite or other carbon containing powders or ceramic powders or both.