Semi-solid metal casting process of hypoeutectic aluminum alloys

Abstract

A method for the refining of primary aluminum in hypoeutectic alloys by mixing at least two hypoeutectic alloys into a solid/semi-solid hypoeutectic slurry is described. The method provides control of the morphology, size, and distribution of primary Al in a hypoeutectic Al—Si casting by mixing a hypoeutectic Al—Si liquid with solid hypoeutectic Al—Si particles to impart desirable mechanical properties. The invention enables SSM molding of hypoeutiectic alloys without the need for secondary processing steps associated with other rheocasting processes.

1 - 17 . (canceled)  
   
   
       18 . A semi-solid metal product, comprising: 
 the product made by heating a first aluminum-silicon hypoeutectic alloy to a liquid state, combining the first alloy and a second aluminum-silicon hypoeutectic alloy at different temperatures to form a semi-solid metal, cooling the semi-solid metal for a length of time effective to increase nucleation of primary aluminum particles therein, and casting the semi-solid metal.    
   
   
       19 . The product of  claim 18 , wherein the product is also made by choosing the length of time to be effective in restricting growth of a primary aluminum phase in the semi-solid metal.  
   
   
       20 . The product of  claim 18 , wherein the product is also made by combining a third aluminum-silicon hypoeutectic alloy with the first and second alloys.  
   
   
       21 . The product of  claim 18 , wherein at least one of the first and second alloys comprises from about 6 to about 8 percent silicon.  
   
   
       22 . The product of  claim 21 , wherein at least one of the first and second alloys comprises about 7 percent silicon.  
   
   
       23 . The product of  claim 18 , wherein the product is also made by heating the second alloy before combining it with the first alloy.  
   
   
       24 . The product of  claim 23 , wherein the product is also made by heating the first alloy to a higher temperature than the heated second alloy.  
   
   
       25 . The product of  claim 23 , wherein the product is also made by heating the second alloy to a temperature from about 22° C. to about 660° C.  
   
   
       26 . The product of  claim 18 , wherein the product comprises aluminum particles having an average diameter from about 40 microns to about 60 microns.  
   
   
       27 . The product of  claim 18 , wherein the product is also made by heating the first alloy to a temperature from about 577° C. to about 715° C.  
   
   
       28 . The product of  claim 27 , wherein the product is also made by heating the first alloy to a temperature from about 577° C. to about 580° C.  
   
   
       29 . The product of  claim 27 , wherein the product is also made by heating the first alloy to a temperature from about 690° C. to about 715° C.  
   
   
       30 . The product of  claim 27 , wherein the product is also made by heating the first alloy to a temperature of about 640° C. and squeeze casting.  
   
   
       31 . The product of  claim 18 , wherein the product comprises aluminum particles having a compaction ratio from about 1.6 to about 3.0.  
   
   
       32 . The product of  claim 31 , wherein the product comprises aluminum particles having a compaction ratio from about 1.6 to about 1.8.  
   
   
       33 . The product of  claim 18 , wherein the product is also made by choosing the difference in temperature between the first alloy and the second alloy to be effective in producing the product comprising more homogeneous distribution of aluminum particles as compared to aluminum particles in a cast product made by traditional casting methods.  
   
   
       34 . A cast product, comprising: 
 an alloy comprising:    a first aluminum-silicon hypoeutectic alloy heated to a liquid state; and    a second aluminum-silicon hypoeutectic alloy mixed with the first alloy; wherein the first alloy and the second alloy are allowed to cool for a length of time effective to increase nucleation of primary aluminum particles.    
   
   
       35 . The cast product of  claim 34 , wherein the length of time is effective to restrict growth of a primary aluminum phase.  
   
   
       36 . The cast product of  claim 34 , where in the aluminum particles have an average diameter from about 40 microns to about 60 microns.  
   
   
       37 . The cast product of  claim 34 , wherein the aluminum particles have a compaction ratio from about 1.6 to about 3.0.  
   
   
       38 . The product of  claim 37 , wherein the aluminum particles have a compaction ratio from about 1.6 to about 1.8.  
   
   
       39 . The product of  claim 34 , where in the method is effective to produce a cast product comprising more homogeneous distribution of aluminum particles as compared to aluminum particles in a cast product made by traditional casting methods.