Functionally graded w-cu composite

Abstract

A method for fabricating a functionally graded tungsten-copper composite (W—Cu FGC) may include the following steps. A binder alloy powder may be prepared that may include mechanically alloyed metal powders of nickel (Ni), copper (Cu), and manganese (Mn); the binder alloy powder may be mixed with a pure tungsten (W) powder to obtain a modified W powder; a plurality of W—Cu composite powders may be prepared by mixing the modified W powder with pure copper powder with different ratios; the plurality of W—Cu composite powders may then be stacked inside a die; the stacked plurality of W—Cu composite powders may be pressed inside the die to obtain a W—Cu compact; and the W—Cu compact may be sintered to obtain a W—Cu FGC.

What is claimed is: 
     
         1 . A method for fabricating a functionally graded tungsten-copper composite (W—Cu FGC), the method comprising:
 preparing a binder alloy powder, the binder alloy comprising mechanically alloyed metal powders of nickel (Ni), copper (Cu), and manganese (Mn); 
 mixing the binder alloy powder with a pure tungsten (W) powder to obtain a modified W powder; 
 preparing a plurality of W—Cu composite powders by mixing the modified W powder with pure copper powder with different ratios; 
 stacking the plurality of W—Cu composite powders inside a die creating a plurality of stacks, wherein a composition of each respective one of the plurality of stacks changes incrementally between W and Cu for each respective stack compared to any previous stack; 
 pressing the stacked plurality of W—Cu composite powders inside the die to obtain a W—Cu compact; and 
 sintering the W—Cu compact to obtain a W—Cu FGC. 
 
     
     
         2 . The method of  claim 1 , wherein the plurality of stacks are eleven. 
     
     
         3 . The method of  claim 2 , where a first stack of the plurality of stacks has a first ratio between W and Cu and a last slack of the plurality of stacks has a last ratio between W and Cu, wherein respective ratios of W and Cu change incrementally between each of the respective stacks between the first and the last stack. 
     
     
         4 . A method for fabricating a functionally graded tungsten-copper composite (W—Cu FGC), the method comprising:
 preparing a binder alloy powder, the binder alloy comprising mechanically alloyed metal powders of nickel (Ni), copper (Cu), and manganese (Mn); 
 mixing the binder alloy powder with a pure tungsten (W) powder to obtain a modified W powder; 
 preparing a plurality of W—Cu composite powders by mixing the modified W powder with pure copper powder with different ratios; 
 stacking the plurality of W—Cu composite powders inside a die; 
 pressing the stacked plurality of W—Cu composite powders inside the die to obtain a W—Cu compact; and 
 sintering the W—Cu compact to obtain a W—Cu FGC. 
 
     
     
         5 . The method according to  claim 4 , wherein the binder alloy powder comprises 20 to 40 wt % of Ni. 
     
     
         6 . The method according to  claim 4 , wherein the binder alloy powder comprises 10 to 80 wt % of Mn. 
     
     
         7 . The method according to  claim 4 , wherein preparing a binder alloy powder involves ball milling pure metal powders of Ni, Cu, and Mn. 
     
     
         8 . The method according to  claim 7 , wherein the ball milling is carried out at 300-400 rpm with a ball to powder ratio of 20 to 1 for 10 to 20 hours. 
     
     
         9 . The method according to  claim 4 , wherein the modified W powder comprises 10 to 30 wt % of the binder alloy powder. 
     
     
         10 . The method according to  claim 4 , wherein content of the modified W powder in the plurality of W—Cu composite powders varies between 100 vol % to 0 vol %. 
     
     
         11 . The method according to  claim 4 , wherein stacking the plurality of W—Cu composite powders inside a die involves filling the die with the W—Cu composite powders layer by layer, such that each layer may have a different composition. 
     
     
         12 . The method according to  claim 4 , pressing the stacked plurality of W—Cu composite powders inside the die includes exerting a pressure of 500-1000 MPa on the stacked plurality of W—Cu composite powders. 
     
     
         13 . The method according to  claim 4 , wherein sintering the W—Cu compact includes heating the W—Cu compact with a specific heating rate in a sintering process at a temperature of at most 1000° C. 
     
     
         14 . The method according to  claim 13 , wherein the specific heating rate is about 10° C./min.