Strip castings of immiscible metals

Abstract

The present invention discloses a method of strip casting an aluminum alloy from immiscible liquids that yields a highly uniform structure of fine second phase particles. The results of the present invention are achieved by using a known casting process to cast the alloy into a thin strip at high speeds. In the method of the present invention, the casting speed is preferably in the region of about 50-300 feet per minute (fpm) and the thickness of the strip preferably smaller than 0.08-0.25 inches. Under these conditions, favorable results are achieved when droplets of the immiscible liquid phase nucleate in the liquid ahead of the solidification front established in the casting process. The droplets of the immiscible phase are engulfed by the rapidly moving freeze front into the space between the Secondary Dendrite Arms (SDA).

What is claimed is: 
     
         1 . A product comprising:
 a cast aluminum alloy product comprising:   an aluminum alloy; and   at least 0.1 weight percent alloying addition,
 wherein the alloying addition is substantially immiscible with molten aluminum, 
 wherein particles of the substantially immiscible alloying addition are uniformly distributed throughout the cast aluminum alloy product, and 
 wherein the particles are deposited between secondary dendrite arms of the cast aluminum alloy product. 
   
     
     
         2 . The product according to  claim 1 , wherein the particles are less than three microns in size. 
     
     
         3 . The product according to  claim 1 , wherein the alloying addition comprises at least one of Sn, Pb, Bi, Cd, and Sb. 
     
     
         4 . The product according to  claim 1 , wherein the alloying addition comprises at least 0.1 weight % Sn. 
     
     
         5 . The product according to  claim 1 , wherein the alloying addition comprises at least 0.1 weight % Pb. 
     
     
         6 . The product according to  claim 1 , wherein the alloying addition comprises at least 0.1 weight % Bi. 
     
     
         7 . The product according to  claim 1 , wherein the alloying addition comprises at least 0.1 weight % Cd. 
     
     
         8 . The product according to  claim 1 , wherein the alloying addition comprises at least 0.1 weight % Sb. 
     
     
         9 . A method of casting metals comprising:
 providing a molten aluminum alloy to a casting apparatus,
 the molten aluminum alloy comprising at least about 0.1 weight percent alloying addition, wherein the alloying addition is substantially immiscible with molten aluminum, 
 the casting apparatus having a first casting surface, a second casting surface, and a nip formed between the first and second casting surface; 
   advancing the aluminum alloy, wherein a point of complete solidification of the aluminum alloy is formed at the nip, wherein the aluminum alloy is advanced through the nip, by rotation of the first casting surface and by rotation of the second casting surface, wherein fine droplets of the immiscible alloying addition deposit between secondary dendrite arms of the aluminum alloy, wherein the fine droplets are less than three microns in size, and wherein the fine droplets of the immiscible alloying addition are uniformly distributed throughout the alloy.   
     
     
         10 . The method according to  claim 9 , wherein the nip comprises a thickness ranging from 0.08 inches to 0.25 inches. 
     
     
         11 . The method according to  claim 9 , wherein the alloying addition comprises at least one of Sn, Pb, Bi, Cd, and Sb. 
     
     
         12 . The method according to  claim 9 , wherein the alloying addition comprises at least 0.1 weight % Sn. 
     
     
         13 . The method according to  claim 9 , wherein the alloying addition comprises at least 0.1 weight % Pb. 
     
     
         14 . The method according to  claim 9 , wherein the alloying addition comprises at least 0.1 weight % Bi. 
     
     
         15 . The method according to  claim 9 , wherein the alloying addition comprises at least 0.1 weight % Cd. 
     
     
         16 . The method according to  claim 9 , wherein the alloying addition comprises at least 0.1 weight % Sb.