Castable high temperature aluminum alloy

Abstract

A dispersion strengthened castable aluminum-rare earth alloy provides high strength at elevated temperatures. In one example, the aluminum alloy includes approximately 1.0 to 20.0% by weight of gadolinium, approximately 0.1 to 10.0% total by weight of other rare earth elements including ytterbium, erbium or yttrium, and approximately 0.1 to 15.0% total by weight of minor alloy elements. In another example, the aluminum alloy includes approximately 1.0 to 20% by weight of ytterbium, approximately 0.1 to 10.0% total by weight of other rare earth elements including gadolinium, erbium or yttrium, and approximately 0.1 to 10.0% total by weight of minor alloy elements. After casting, the aluminum alloy is solidified and cooled. During solidification, the aluminum matrix excludes the rare earth alloy elements from the aluminum matrix, forming eutectic rare earth element-containing dispersoids that strengthen the aluminum matrix.

What is claimed is:  
     
         1 . An aluminum alloy comprising: 
 approximately 1.0 to 20.0% by weight of a first rare earth element selected from the group consisting of ytterbium and gadolinium;    a plurality of insoluable particles formed of said first rare earth element;    approximately 0.1 to 10.0% by weight of at least one second rare earth element selected from the group consisting of gadolinium, erbium and yttrium if said first rare earth element is ytterbium or the group consisting of ytterbium, erbium and yttrium if said first rare earth element is gadolinium; and    the balance of the aluminum alloy is aluminum.    
     
     
         2 . The aluminum alloy as recited in  claim 1  further including approximately 1.0 to 15% total by weight of at least one minor alloy element.  
     
     
         3 . The aluminum alloy as recited in  claim 2  wherein said at least one minor alloy element is selected from the group consisting of copper, zinc, silver, magnesium, manganese, tin, titanium, cobalt and calcium.  
     
     
         4 . The aluminum alloy as recited in  claim 1  wherein said first rare earth element is ytterbium and said plurality of insoluable particles are formed of said ytterbium  
     
     
         5 . The aluminum alloy as recited in  claim 4  wherein said at least one second rare earth element is said yttrium.  
     
     
         6 . The aluminum alloy as recited in  claim 5  including approximately 14.0% to 15% of said ytterbium and approximately 4.0% of said yttrium.  
     
     
         7 . The aluminum alloy as recited in  claim 1  wherein said first rare earth element is gadolinium and said plurality of insoluable particles are formed of said gadolinium  
     
     
         8 . The aluminum alloy as recited in  claim 7  wherein said at least one second rare earth element is said yttrium.  
     
     
         9 . The aluminum alloy as recited in  claim 8  including approximately 13.0 to 16.0% of said gadolinium and approximately 4.0% of said yttrium.  
     
     
         10 . A gas turbine engine component comprising: 
 components of an aluminum alloy including approximately 1.0 to 20.0% of a first rare earth element selected from the group consisting of gadolinium and ytterbium, a plurality of insoluable particles formed of said first rare earth element, approximately 0.01 to 10.0% by weight of at least one second rare earth element selected from the group consisting of gadolinium, erbium and yttrium if said first rare earth element is ytterbium or the group consisting of ytterbium, erbium and yttrium if said first rare earth element is gadolinium, and the balance of the aluminum alloy is aluminum.    
     
     
         11 . The gas turbine engine component as recited in  claim 10  further including approximately 1.0 to 15% total by weight of at least one minor alloy element.  
     
     
         12 . The gas turbine engine component as recited in  claim 11  wherein said at least one minor alloy element is selected from the group consisting of copper, zinc, silver, magnesium, manganese, tin, titanium, cobalt and calcium.  
     
     
         13 . The gas turbine engine component as recited in  claim 10  wherein said first rare earth element is ytterbium and said plurality of insoluable particles are formed of said ytterbium  
     
     
         14 . The gas turbine engine component as recited in  claim 13  wherein said at least one second rare earth element is yttrium.  
     
     
         15 . The gas turbine engine component as recited in  claim 10  wherein said first rare earth element is gadolinium and said plurality of insoluable particles are formed of said gadolinium.  
     
     
         16 . The gas turbine engine component as recited in  claim 15  wherein said at least one second rare earth element is yttrium.  
     
     
         17 . A method of forming an aluminum alloy comprising the steps of: 
 a) melting aluminum to a molten state;    b) adding approximately 1.0 to 20.0% by weight of a first rare earth element selected from the group consisting of gadolinium and ytterbium;    c) forming a plurality of insoluable particles of the first rare earth element;    and    d) adding approximately 0.1 to 10.0% by weight of at least one second rare earth element selected from the group consisting of gadolinium, erbium and yttrium if said first rare earth element is ytterbium or the group consisting of ytterbium, erbium and yttrium if said first rare earth element is gadolinium.    
     
     
         18 . The method as recited in  claim 17  wherein the first rare earth element is ytterbium and said step c includes forming the plurality of insoluable particles of the ytterbium  
     
     
         19 . The aluminum alloy as recited in  claim 18  wherein the at least one second rare earth element is yttrium.  
     
     
         20 . The method as recited in  claim 17  wherein the first rare earth element is gadolinium said and step c includes forming the plurality of insoluable particles of the gadolinium  
     
     
         21 . The aluminum alloy as recited in  claim 20  wherein the at least one second rare earth element is yttrium.  
     
     
         22 . The method as recited in  claim 16  further comprising the steps of casting the aluminum alloy, solidifying the aluminum alloy and forming the plurality of insoluable particles.  
     
     
         23 . The method as recited in  claim 22  wherein said step of casting is selected from sand casting, investment casting and die casting.  
     
     
         24 . The method as recited in  claim 17  further including the step of adding approximately 1.0 to 15% total by weight of at least one minor alloy element.  
     
     
         25 . The method as recited in  claim 24  wherein the at least one minor alloy element is selected from the group consisting of copper, zinc, silver, magnesium, manganese, tin, titanium, cobalt and calcium.