Methods for sintering bodies of earth-boring tools and structures formed during the same

Abstract

A first green or brown object is sintered while being supported by a second green or brown object in a furnace, and a body of an earth-boring tool is formed from the first object. An object is sectioned to form first and second structures, and the first structure is sintered within a furnace while it is supported by (e.g., resting on) the second structure. A layer of powder material is provided on a green or brown object, another green or brown object is rested on the powder material over the first green or brown object, and the first and second green or brown objects are sintered with the powder material therebetween. Intermediate structures formed during fabrication of a body of an earth-boring tool include a layer of powder between a green or brown tool body precursor and a green or brown structure supporting the green or brown tool body.

1 . A method of forming a body of an earth-boring tool, comprising:
 supporting a less than fully sintered first structure with a less than fully sintered second structure in a furnace;   sintering the first structure to at least substantially form a body of an earth-boring tool while the first structure is supported by the second structure in the furnace; and   separating at least a portion of the second structure from the first structure after sintering the first structure to at least substantially form the body of the earth-boring tool.   
     
     
         2 . The method of  claim 1 , wherein the less than fully sintered first structure comprises a first green structure prior to sintering, and the less than fully sintered second structure comprises a second green structure prior to sintering. 
     
     
         3 . The method of  claim 1 , wherein the less than fully sintered first structure comprises a first brown structure prior to sintering, and the less than fully sintered second structure comprises a second brown structure prior to sintering. 
     
     
         4 . The method of  claim 1 , wherein sintering the first structure comprises sintering the first structure to at least substantially form a bit body of an earth-boring rotary drill bit. 
     
     
         5 . The method of  claim 1 , further comprising providing a plurality of contact structures between the less than fully sintered first structure and the less than fully sintered second structure prior to sintering the first structure and the second structure in the furnace. 
     
     
         6 . The method of  claim 5 , wherein providing a plurality of contact structures between the less than fully sintered first structure and the less than fully sintered second structure further comprises laterally separating the contact structures of the plurality of contact structures from one another. 
     
     
         7 . The method of  claim 6 , further comprising forming each contact structure of the plurality of contact structures to contact the less than fully sintered first structure at a point. 
     
     
         8 . The method of  claim 5 , wherein the plurality of contact structures are integrally formed with one of the less than fully sintered first structure and the less than fully sintered second structure. 
     
     
         9 . A method of forming a body of an earth-boring tool, comprising:
 sectioning a three-dimensional object to form a first structure and a second structure from the three-dimensional object;   supporting the first structure with the second structure in a furnace;   sintering the first structure and the second structure in the furnace while the first structure is supported on the second structure; and   forming a body of an earth-boring tool from the first structure.   
     
     
         10 . The method of  claim 9 , further comprising pressing a powder material to form the three-dimensional object. 
     
     
         11 . The method of  claim 9 , further comprising providing a powder material between the first structure and the second structure prior to sintering the first structure and the second structure in the furnace. 
     
     
         12 . The method of  claim 9 , further comprising forming a body of an earth-boring rotary drill bit from the first structure. 
     
     
         13 . The method of  claim 9 , further comprising providing a plurality of contact structures between the first structure and the second structure prior to sintering the first structure and the second structure in the furnace. 
     
     
         14 . A method of forming a sintered body of an earth-boring tool, comprising:
 providing a layer of unconsolidated powder material on a surface of a first less than fully sintered object;   resting a second less than fully sintered object on the powder material over the surface of the first less than fully sintered object; and   sintering the first less than fully sintered object and the second less than fully sintered object with the unconsolidated powder material therebetween.   
     
     
         15 . The method of  claim 14 , further comprising causing the first less than fully sintered object and the second less than fully sintered object to have at least substantially identical material compositions. 
     
     
         16 . The method of  claim 15 , further comprising forming the first less than fully sintered object and the second less than fully sintered object from a unitary structure. 
     
     
         17 . A method of forming a body of an earth-boring tool, comprising:
 sectioning a three-dimensional object to form a less than fully sintered support structure and a less than fully sintered tool body from the three-dimensional object;   placing the less than fully sintered tool body over the less than fully sintered support structure within a furnace and supporting the less than fully sintered tool body with the less than fully sintered support structure; and   simultaneously sintering the less than fully sintered support structure and the less than fully sintered tool body in the furnace.   
     
     
         18 . The method of  claim 17 , further comprising pressing a powder material to form the three-dimensional object. 
     
     
         19 . The method of  claim 18 , wherein pressing a powder material to form the three-dimensional object comprises:
 mixing a plurality of hard particles with a plurality of particles comprising a matrix material to form a powder mixture; and   pressing the powder mixture to form the three-dimensional object.   
     
     
         20 . The method of  claim 19 , further comprising selecting the hard particles to comprise a material selected from the group consisting of diamond, boron carbide, boron nitride, aluminum nitride, silicon nitride, and carbides or borides of the group consisting of W, Ti, Mo, Nb, V, Hf, Zr, Si, Ta, and Cr. 
     
     
         21 . The method of  claim 19 , further comprising selecting the matrix material from the group consisting of the matrix material selected from the group consisting of iron-based alloys, nickel-based alloys, cobalt-based alloys, titanium-based alloys; aluminum-based alloys, iron- and nickel-based alloys, iron- and cobalt-based alloys, and nickel- and cobalt-based alloys. 
     
     
         22 . The method of  claim 17 , further comprising providing a powder material between the less than fully sintered tool body and the less than fully sintered support structure within the furnace prior to sintering the less than fully sintered support structure and the less than fully sintered tool body in the furnace. 
     
     
         23 . The method of  claim 22 , further comprising forming the powder material to comprise a ceramic material. 
     
     
         24 . The method of  claim 22 , further comprising forming the powder material to comprise a plurality of particles having an average particle size between about 0.1 microns and about 200 microns. 
     
     
         25 . The method of  claim 22 , wherein providing a powder material between the less than fully sintered tool body and the less than fully sintered support structure comprises providing a monolayer of particles between the less than fully sintered tool body and the less than fully sintered support structure. 
     
     
         26 . The method of  claim 17 , wherein sectioning a three-dimensional object comprises cutting an at least generally cylindrical object in a plane oriented at least substantially perpendicular to a longitudinal axis of the at least generally cylindrical object to form the less than fully sintered support structure and a less than fully sintered tool body from the at least generally cylindrical object. 
     
     
         27 . The method of  claim 17 , further comprising providing a plurality of contact structures between the less than fully sintered support structure and the less than fully sintered tool body prior to sintering the less than fully sintered support structure and the less than fully sintered tool body in the furnace. 
     
     
         28 . An intermediate structure formed during the fabrication of a body for an earth-boring tool, comprising:
 a less than fully sintered support structure;   a layer of unconsolidated powder material on a surface of the less than fully sintered support structure; and   a less than fully sintered body for an earth-boring tool resting on the layer of unconsolidated powder material and supported by the less than fully sintered support structure.   
     
     
         29 . The intermediate structure of  claim 28 , wherein the less than fully sintered support structure and the less than fully sintered body for an earth-boring tool have substantially identical material compositions. 
     
     
         30 . The intermediate structure of  claim 28 , wherein the less than fully sintered support structure and the less than fully sintered body for an earth-boring tool each comprise a portion separated from a single unitary structure. 
     
     
         31 . The intermediate structure of  claim 28 , wherein the less than fully sintered body for an earth-boring tool comprises a less than fully sintered bit body for an earth-boring rotary drill bit.