Methods of forming earth boring rotary drill bits including bit bodies comprising reinforced titanium or titanium based alloy matrix materials

Abstract

Earth-boring rotary drill bits include bit bodies comprising a composite material including a plurality of hard phase regions or particles dispersed throughout a titanium or titanium-based alloy matrix material. The bits further include a cutting structure disposed on a face of the bit body. In some embodiments, the bit bodies may include a plurality of regions having differing material compositions. For example, the bit bodies may include a first region comprising a plurality of hard phase regions or particles dispersed throughout a titanium or titanium-based alloy matrix material, and a second region comprising a titanium or a titanium-based alloy material. Methods for forming such drill bits include at least partially sintering a plurality of hard particles and a plurality of particles comprising titanium or a titanium-based alloy material to form a bit body comprising a particle-matrix composite material. A shank may be attached directly to the bit body.

1 . A method of forming an earth-boring rotary drill bit, the method comprising:
 providing a bit body comprising a particle-matrix composite material, providing a bit body comprising:
 providing a green powder component comprising:
 a plurality of particles each comprising a hard material; and 
 a plurality of particles each comprising titanium or a titanium-based alloy material; and 
 
 at least partially sintering the green powder component; 
   providing a shank configured for attachment to a drill string; and   attaching the shank directly to the bit body.   
     
     
         2 . The method of  claim 1 , wherein providing a green powder component comprises:
 pressing a first powder mixture to form a first green structure, the first powder mixture comprising at least a portion of the plurality of particles each comprising a hard material and a portion of the plurality of particles each comprising titanium or a titanium-based alloy material;   pressing a second powder mixture to fowl a second green structure, the second powder mixture comprising a portion of the plurality of particles each comprising titanium or a titanium-based alloy material; and   assembling the first green structure with the second green structure to form the green powder component.   
     
     
         3 . The method of  claim 2 , wherein pressing the first powder mixture comprises heating the first powder mixture and subjecting the first powder mixture to substantially isostatic pressure, and wherein pressing the second powder mixture comprises heating the second powder mixture and subjecting the second powder mixture to substantially isostatic pressure. 
     
     
         4 . The method of  claim 1 , wherein providing a green powder component comprises:
 providing a first powder mixture in a first region of a deformable container, the first powder mixture comprising at least a portion of the plurality of particles each comprising a hard material and a portion of the plurality of particles each comprising titanium or a titanium-based alloy material;   providing a second powder mixture in a second region of the deformable container adjacent the first powder mixture, the second powder mixture comprising a portion of the plurality of particles each comprising titanium or a titanium-based alloy material;   sealing the first powder mixture and the second powder mixture within the deformable container; and   subjecting the deformable container to substantially isostatic pressure.   
     
     
         5 . The method of  claim 1 , further comprising machining at least one feature in the green powder component prior to at least partially sintering the green powder component. 
     
     
         6 . The method of  claim 1 , wherein at least partially sintering the green powder component comprises:
 partially sintering the green powder component to form a brown structure;   machining at least one feature in the brown structure; and   sintering the brown structure to a desired final density.   
     
     
         7 . The method of  claim 1 , wherein attaching the shank directly to the bit body comprises:
 providing a retaining member;   aligning at least one aperture extending through an outer wall of the shank with at least one groove in a surface of the bit body; and   inserting the retaining member through at least a portion of the at least one aperture extending through the outer wall of the shank and at least a portion of the at least one groove in the surface of the bit body.   
     
     
         8 . The method of  claim 7 , wherein inserting the retaining member comprises providing a substantially uniform gap between at least one surface of the shank and at least one surface of the bit body. 
     
     
         9 . The method of  claim 8 , wherein the substantially uniform gap is between about 50 microns (0.002 inch) and about 150 microns (0.006 inch). 
     
     
         10 . The method of  claim 8 , further comprising providing a brazing alloy in the substantially uniform gap between the at least one surface of the shank and the at least one surface of the bit body. 
     
     
         11 . The method of  claim 8 , further comprising welding an interface between the shank and the bit body. 
     
     
         12 . The method of  claim 1 , further comprising subjecting at least a portion of the bit body to a thermal processing treatment comprising at least one of annealing, solution-treating, and aging. 
     
     
         13 . The method of  claim 1 , further comprising providing a layer of titanium nitride on at least a portion of a surface of the bit body configured to engage a subterranean formation during drilling.