Method for producing a cemented carbide body

Abstract

The invention relates to a method for producing a cemented carbide body, wherein in a mixing and/or grinding process, preferably in a wet grinding process, tungsten carbide powder (WC powder) and metallic binder material comprising cobalt powder (Co), nickel (Ni) and aluminum (Al) are mixed to form a powder mixture, wherein a green compact is pressed from at least a portion of the powder mixture and wherein the green compact is sintered in a sintering step under the influence of temperature and pressure in such a way that the cemented carbide body is formed after a cooling step following the sintering step. To create an easily controllable and reliable process for the production of a cemented carbide body, which is characterized by improved wear resistance and, at the same time, a high fracture strength, provision is made in accordance with the invention for nickel aluminide, preferably nickel aluminide powder, in particular Ni 3 Al powder, to be added to the mixing and/or grinding process as an intermetallic phase material.

1 - 22 . (canceled) 
     
     
         23 . A method for producing a cemented carbide body, comprising:
 combining a tungsten carbide powder and a metallic binder material comprising cobalt, nickel, and aluminum to form a powder mixture;   adding nickel aluminide to the powder mixture;   forming a green compact from the powder mixture;   sintering the green compact at a first temperature and a first pressure; and   cooling the compact to form a cemented carbide body comprising a binder phase and an intermetallic phase.   
     
     
         24 . The method of  claim 23 , wherein the tungsten carbide powder and the metallic binder material are combined in a mixing process or a milling process. 
     
     
         25 . The method of  claim 24 , wherein the mixing process or the milling process is a multi-stage process comprising at least a first mixing or milling step and a second mixing or milling step, and wherein the nickel aluminide is added before a final mixing or milling step. 
     
     
         26 . The method of  claim 24 , wherein the tungsten carbide powder and the metallic binder material are combined in a wet milling process. 
     
     
         27 . The method of  claim 23 , wherein at least a portion of the intermetallic phase comprises (M,Y) 3 (Al,X), wherein M is Ni, Y comprises Co, and X comprises W. 
     
     
         28 . The method of  claim 23 , wherein, when cooling the compact, the sintered body is kept at a temperature range between 400° C. and a solvus temperature of the sintered body for a period ranging from 0.25 to 24 hours. 
     
     
         29 . The method of  claim 23 , wherein the green compact comprises tungsten carbide in an amount ranging from 70 wt % to 95 wt % of the green compact, cobalt in an amount ranging from 1 wt % to 19 wt % of the green compact, and nickel aluminide in an amount ranging from 1 wt % to 28 wt % of the green compact. 
     
     
         30 . The method of  claim 23 , wherein the nickel aluminide is produced in a smelting process or added as a material produced in a melt process. 
     
     
         31 . The method of  claim 23 , wherein the nickel aluminide has a mean particle size of less than 70 μm. 
     
     
         32 . The method of  claim 23 , further comprising a preparation step, the preparation step comprising combining the nickel aluminide with a milling liquid and coarse-grained tungsten carbide to form a milling mixture and mixing the milling mixture such that crushed nickel aluminide is formed from the nickel aluminide. 
     
     
         33 . The method of  claim 32 , wherein the tungsten carbide has a mean particle size of greater than 20 μm. 
     
     
         34 . The method of  claim 32 , wherein the tungsten carbide is macrocrystalline tungsten carbide, monocrystalline tungsten carbide, or a combination thereof. 
     
     
         35 . The method of  claim 32 , wherein the preparation step or a subsequent milling step comprises mixing at least the cobalt, at least one alloying constituent, or a combination thereof with the nickel aluminide, the crushed nickel aluminide, or a combination thereof. 
     
     
         36 . The method of  claim 32 , wherein the milling mixture comprises nickel aluminide in an amount ranging from 8 wt % to 50 wt % 
     
     
         37 . The method of  claim 32 , further comprising a milling step subsequent to the preparation step, wherein tungsten carbide powder is added to the milling mixture until the milling mixture contains an amount of tungsten carbide ranging from 70 wt % to 95 wt %, and wherein the crushed nickel aluminide is ground into finely-crushed nickel aluminide. 
     
     
         38 . The method of  claim 23 , wherein the green compact is sintered at a temperature of 1350° C. to 1550° C. using a liquid phase sintering process. 
     
     
         39 . The method of  claim 38 , wherein the cobalt and the intermetallic phase are at least partially dissolved in each other in a melt during the liquid phase sintering process, wherein, when cooling the compact or during a thermal treatment step subsequent to the sintering process, the intermetallic phase material is formed in the binder phase, and wherein the intermetallic phase material has a structural formula of (M,Y) 3 (Al,X), wherein M is Ni, Y comprises Co, and X comprises tungsten. 
     
     
         40 . The method of  claim 23 , wherein at least a portion of the intermetallic phase material has a maximum particle size of 1500 nm and wherein at least a portion of the intermetallic phase material has an L12 crystal structure. 
     
     
         41 . The method of  claim 23 , wherein the nickel aluminide is present as an intermetallic phase material. 
     
     
         42 . The method of  claim 23 , further comprising adding Nb, Ti, Ta, Mo, V, Cr, or a combination thereof to the powder mixture, such that the metallic binder material further comprises the Nb, Ti, Ta, Mo, V, Cr or the combination thereof. 
     
     
         43 . The method of  claim 42 , wherein the Nb, Ti, Ta, Mo, V, Cr or the combination thereof is dissolved in the binder phase. 
     
     
         44 . The method of  claim 23 , wherein a carbon content of the cemented carbide material is stoichiometric or substoichiometric, and wherein the carbon content in the cemented carbide material ranges from C stoich  (wt %)-0.003*binder content (wt %) to C stoich  (wt %)-0.012*binder content wt %. 
     
     
         45 . The method of  claim 23 , wherein the binder phase contains 15 at % or less combined Nb, Ti, Ta, Mo, V, and Cr content. 
     
     
         46 . The method of  claim 23 , wherein the tungsten carbide is present in the cemented carbide material as grains having a mean particle diameter ranging from 1 μm to 15 μm. 
     
     
         47 . The method of  claim 23 , wherein the binder phase comprises less than 5 wt % Fe.