Heat treatable L12 aluminum alloys

Abstract

High temperature heat treatable aluminum alloys that can be used at temperatures from about −420° F. (−251° C.) up to about 650° F. (343° C.) are described. The alloys are strengthened by dispersion of particles based on the L1 2 intermetallic compound Al 3 X. These alloys comprise aluminum; silicon; at least one of scandium, erbium, thulium, ytterbium, and lutetium; and at least one of gadolinium, yttrium, zirconium, titanium, hafnium, and niobium. Magnesium and copper are optional alloying elements.

1 . A heat treatable aluminum alloy comprising:
 about 4.0 to about 25.0 weight percent silicon;   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 weight percent thulium, about 0.1 to about 15.0 weight percent ytterbium, and about 0.1 to about 12 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.   
   
   
       2 . The alloy of  claim 1 , wherein the alloy comprises an aluminum solid solution matrix containing a plurality of dispersed Al 3 X second phases having L1 2  structures, wherein X includes at least one first element and at least one second element. 
   
   
       3 . The alloy of  claim 1  further comprising about 0.2 to about 3.0 weight percent magnesium. 
   
   
       4 . The alloy of  claim 3 , wherein the alloy comprises from about 0.3 weight percent to about 1.5 weight percent magnesium. 
   
   
       5 . The alloy of  claim 1  further comprising about 0.5 to about 5.0 weight percent copper. 
   
   
       6 . The alloy of  claim 5  wherein the alloy comprises about 0.3 to about 1.5 weight percent magnesium and about 1.0 to about 4.0 weight percent copper. 
   
   
       7 . The alloy of  claim 1  further comprising about 0.2 to about 3.0 weight percent magnesium and about 0.5 to about 5.0 weight percent copper. 
   
   
       8 . The alloy of  claim 1  further comprising at least one of about 0.001 to about 0.1 weight percent sodium, about 0.001 to about 0.1 weight percent calcium, about 0.001 to about 0.1 weight percent strontium, about 0.001 to about 0.1 weight percent antimony, about 0.001 to about 0.1 weight percent barium, and about 0.001 to about 0.1 weight percent phosphorus. 
   
   
       9 . The alloy of  claim 1  comprising no more than about 1.0 weight percent total other elements including impurities. 
   
   
       10 . The alloy of  claim 1  comprising no more than about 0.1 weight percent iron, about 0.1 weight percent chromium, about 0.1 weight percent manganese, about 0.1 weight percent vanadium, about 0.1 weight percent cobalt, and about 0.1 weight percent nickel. 
   
   
       11 . The alloy of  claim 1 , wherein the amount of silicon ranges from about 4.0 to about 18.0 weight percent. 
   
   
       12 . The alloy of  claim 11 , wherein the amount of silicon ranges from about 5.0 to about 11.0 weight percent. 
   
   
       13 . The alloy of  claim 1 , which is formed by a process selected from casting, deformation processing, and rapid solidification processing. 
   
   
       14 . The alloy of  claim 13 , which is heat treated after forming. 
   
   
       15 . The alloy of  claim 13 , in which the alloy is heat treated by a solution anneal at a temperature of about 800° F. (426° C.) to about 1100° F. (593° C.) for about 30 minutes to four hours, followed by quenching. 
   
   
       16 . The alloy of  claim 15 , wherein the quenching is in liquid. 
   
   
       17 . The alloy of  claim 15 , wherein the alloy is aged after quenching. 
   
   
       18 . The alloy of  claim 17 , wherein the aging is at a temperature of about 200° F. (93° C.) to about 600° F. (315° C.) for about two to forty-eight hours. 
   
   
       19 . The heat treatable aluminum alloy of  claim 1 , wherein the alloy is capable of being used at temperatures from about −420° F. (−251° C.) up to about 650° F. (343° C.). 
   
   
       20 . A heat treatable aluminum alloy comprising:
 about 4.0 to about 25.0 weight percent silicon; and   an aluminum solid solution matrix containing a plurality of dispersed Al 3 X second phases having L1 2  structures where X comprises at least one of scandium, erbium, thulium, ytterbium, lutetium, and at least one of gadolinium, yttrium, zirconium, titanium, hafnium, niobium.   
   
   
       21 . The alloy of  claim 20 , wherein the alloy comprises at least one of: about 0.2 to about 3.0 weight percent magnesium and about 0.5 to about 5.0 weight percent copper. 
   
   
       22 . The alloy of  claim 20 , wherein the alloy comprises at least one of: 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 weight percent thulium, about 0.1 to about 15.0 weight percent ytterbium, about 0.1 to about 12 weight percent lutetium, and 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. 
   
   
       23 . A method of forming a heat treatable aluminum alloy, the method comprising:
 (a) forming a melt comprising:
 about 4.0 to about 25.0 weight percent silicon; 
 about 0.2 to about 3.0 weight percent magnesium; 
 about 0.5 to about 5.0 weight percent copper; 
 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 weight percent thulium, about 0.1 to about 15.0 weight percent ytterbium, and about 0.1 to about 12 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; 
   (b) solidifying the melt to form a solid body; and   (c) heat treating the solid body.   
   
   
       24 . The method of  claim 23  further comprising:
 refining the structure of the solid body by deformation processing including at least one of: extrusion, forging and rolling.   
   
   
       25 . The method of  claim 23 , wherein solidifying comprises a casting process. 
   
   
       26 . The method of  claim 23 , wherein solidifying comprises a rapid solidification process in which the cooling rate is greater than about 10 3 ° C./second including at least one of: powder processing, atomization, melt spinning, splat quenching, spray deposition, cold spray, plasma spray, laser melting and deposition, ball milling, and cryomilling. 
   
   
       27 . The method of  claim 23 , wherein the heat treating comprises:
 solution heat treatment at about 800° F. (426° C.) to about 1100° F. (593° C.) for about thirty minutes to four hours; and   quenching; and   aging at a temperature of about 200° F. (93° C.) to about 600° F. (315° C.) for about two to forty eight hours.