Aluminum Alloys and Manufacture Methods

Abstract

A composition comprises, in weight percent: Al as a largest constituent; 3.0-6.0 Cr; 1.5-4.0 Mn; 0.1-3.5 Co; and 0.3-2.0 Zr.

1 . A composition comprising, in weight percent:
 Al as a largest constituent;   3.0-6.0 Cr;   1.5-4.0 Mn;   0.1-3.5 Co; and   0.3-2.0 Zr.   
     
     
         2 . The composition of  claim 1  wherein, in atomic percent content, Co divided by the sum (Cr+Mn) is less than or equal to 0.07. 
     
     
         3 . The composition of  claim 1  wherein, in atomic percent content, Co divided by the sum (Cr+Mn) is less than or equal to 0.065. 
     
     
         4 . The composition of  claim 1  comprising, in weight percent:
 3.0-6.0 Cr; 
 1.5-4.0 Mn; 
 0.1-1.0 Co; and 
 0.3-1.5 Zr. 
 
     
     
         5 . The composition of  claim 1  comprising, in weight percent:
 3.7-5.2 Cr; 
 2.1-3.0 Mn; 
 0.4-0.6 Co; and 
 0.7-1.1 Zr. 
 
     
     
         6 . The composition of  claim 1  comprising, in weight percent:
 3.7-5.2 Cr; 
 2.1-3.0 Mn; 
 0.4-1.0 Co; and 
 0.7-1.1 Zr. 
 
     
     
         7 . The composition of  claim 1  wherein, in weight percent, the total of all additional elemental contents is not more than 5.0. 
     
     
         8 . The composition of  claim 1  wherein, in weight percent, no additional individual elemental content exceeds 1.0. 
     
     
         9 . The composition of  claim 1  wherein, in weight percent, each of Fe and Si content, if any, does not exceed 0.02. 
     
     
         10 . The composition of  claim 1  wherein, by weight, H content, if any, does not exceed 1 ppm. 
     
     
         11 . The composition of  claim 1  having an icosahedral phase (I-phase). 
     
     
         12 . The composition of  claim 11  wherein a volume fraction of said I-phase is 15% to 30%. 
     
     
         13 . The composition of  claim 11  wherein a characteristic size of said I-phase is less than 200 nm. 
     
     
         14 . The composition of  claim 1  wherein Al 9 Co 2  content, if any, is less than 5% by volume. 
     
     
         15 . A method for manufacturing the composition of  claim 1 , the method comprising:
 atomizing a master alloy;   pressing the atomized alloy to form a billet;   extruding the billet to form an extrusion; and   forging the extrusion.   
     
     
         16 . (canceled) 
     
     
         17 . The composition of  claim 1  having an icosahedral phase (I-phase). 
     
     
         18 . The composition of  claim 17  wherein a volume fraction of said I-phase is 15% to 30%. 
     
     
         19 . The composition of  claim 17  being a powder metallurgical alloy. 
     
     
         20 . The composition of  claim 17  wherein the composition is effective to form a passivating layer when exposed to a salt fog environment.