Thermally stable calcium-aluminum bulk amorphous metals with low mass density

Abstract

The present invention relates to novel calcium based amorphous alloys with high thermal stability and low mass density represented by the general formula: CaAlQ, wherein Q represents one or more elements selected from the group consisting of Cu, Ag, Zn and Mg. Typically, the atomic percentage of the calcium is about 50%.

1 . An amorphous alloy represented by the formula:  
       Ca (100-t) Al x Cu y Ag n Zn m Mg p Ni r    
     wherein 
 x, y, n, m, p and r are atomic percentages, wherein 
 x is a number selected from about 5 to about 35;  
 y is a number selected from 0 to about 15;  
 n, m, p and r are independently a number selected from 0 to about 20, wherein y+n+m+p+r is less than 30; and  
 
 t is the sum of x, y, n, m, p and r, with the proviso that t is a number selected from about 25 to about 55.  
 
   
   
       2 . The alloy of  claim 1 , wherein r is 0.  
   
   
       3 . The alloy of  claim 1 , wherein said alloy is processable into bulk amorphous samples of at least about 2 mm in thickness in its minimum dimension.  
   
   
       4 . The alloy of  claim 1 , wherein said alloy has a Tg of at least 200° C.  
   
   
       5 . The alloy of  claim 2 , wherein x is a number selected from about 25 to about 40, and y+n+m+p is less than 20.  
   
   
       6 . The alloy of  claim 5  wherein the alloy is represented by the formula:  
       Ca (100-t) Al x Q g    wherein Q is an element selected from the group consisting of Cu, Ag, Zn and Mg;    x is a number selected from about 25 to about 35;    g is a number selected from 0 to about 15; and    t is the sum of x and g.    
   
   
       7 . The alloy of  claim 6  wherein g is 0.  
   
   
       8 . The alloy of  claim 1  wherein the alloy is represented by the formula:  
       Ca t Al x Q y Zn m Mg p    
     wherein Q is Cu or Ni; 
 t, x, y, m and p are atomic percentages, wherein 
 t is a number selected from about 50 to about 60;  
 x is a number selected from about 5 to about 15;  
 y is a number selected from about 0 to about 10;  
 m is a number selected from about 10 to about 20; and  
 p is a number selected from 10 to about 15.  
 
 
   
   
       9 . The alloy of  claim 8  wherein t is a number selected from about 55 to about 60, and p is about 15.  
   
   
       10 . An article of manufacture comprising a calcium-based amorphous alloy represented by the formula:  
       Ca (100-t) Al x Cu y Ag n Zn m Mg p Ni r    
     wherein 
 x, y, n, m, p and r are atomic percentages, wherein 
 x is a number selected from about 5 to about 35;  
 p is a number selected from about 5 to about 15;  
 r is a number selected from 0 to about 10;  
 y, n and m are independently a number selected from 0 to about 20, wherein y+n+m is less than about 21; and  
 
 t is the sum of x, y, n, m, p and r, with the proviso that t is a number selected from about 35 to about 55.  
 
   
   
       11 . The article of manufacture of  claim 10  wherein 
 x is a number selected from about 5 to about 15;    y is a number selected from 0 to about 15;    n is 0;    m is a number selected from about 10 to about 20;    p is a number selected from about 10 to about 15;    r is a number selected from 0 to about 10, and t is a number selected from about 35 to about 50.    
   
   
       12 . The article of manufacture of  claim 11  wherein the calcium-based amorphous alloy is represented by the formula:  
       Ca t Al x Q y Zn m Mg p    
     wherein Q is Cu or Ni; 
 t, x, y, m and p are atomic percentages, wherein 
 t is a number selected from about 50 to about 60;  
 x is a number selected from about 10 to about 15;  
 y is a number selected from about 0 to about 10;  
 m is a number selected from about 10 to about 20; and  
 p is a number selected from 10 to about 15.  
 
 
   
   
       13 . The article of manufacture of  claim 10  wherein the calcium-based amorphous alloy is represented by the formula:  
       Ca (100-t) Al x Cu y Ag n Zn m Mg p    
     wherein 
 x, y, n, m and p are atomic percentages, wherein 
 x is a number selected from about 25 to about 35;  
 n is a number selected from about 0 to about 20;  
 m and y are independently a number selected from 0 to about 15,  
 p is a number selected from about 0 to about 20; and  
 
 t is the sum of x, y, n, m and p, with the proviso that t is a number selected from about 35 to about 50.  
 
   
   
       14 . A method of preparing homogeneous ingots of a CaAl-based amorphous alloy comprising Cu or Ag, said method comprising the steps of 
 placing all the elements of the alloy, except the Cu and Ag elements in a boron-nitride-coated graphite crucible;    placing the Cu and Ag elements in the crucible on top of, and in contact with, the other alloy elements; and    melting the combination together to form a homogenous ingot.