Method of making an earth-boring metal matrix rotary drill bit

Abstract

A method of making an earth-boring rotary drill bit includes providing a plurality of hard particles in a mold to define a particle precursor of the first region and the second region and infiltrating the particle precursor of the first region with a molten first matrix material forming a molten first particle-matrix mixture. The method also includes infiltrating the particle precursor of the second region with a molten second matrix material forming a molten second particle-matrix mixture; and cooling the molten first particle-matrix mixture and the molten second particle-matrix mixture to solidify the first matrix material and the second matrix material and form a bit body having a first particle-matrix composite material having a first material composition in the first region and a second particle-matrix composite material having a second material composition in the second region, wherein the first particle-matrix composite material and the second particle-matrix composite material are different.

1 . A method of making an earth-boring rotary drill bit comprising a bit body having a first region configured to carry a one or more cutters for engaging a subterranean earth formation and a second region configured for attachment to a drill string, comprising:
 providing a plurality of hard particles in a mold to define a particle precursor of the first region and the second region;   infiltrating the particle precursor of the first region with a molten first matrix material forming a molten first particle-matrix mixture;   infiltrating the particle precursor of the second region with a molten second matrix material forming a molten second particle-matrix mixture; and   cooling the molten first particle-matrix mixture and the molten second particle-matrix mixture to solidify the first matrix material and the second matrix material and form a bit body having a first particle-matrix composite material having a first material composition in the first region and a second particle-matrix composite material having a second material composition in the second region, wherein the first particle-matrix composite material and the second particle-matrix composite material are different.   
     
     
         2 . The method of making a rotary drill bit of  claim 1 , wherein the hard particles comprise diamond, or metal or semi-metal, nitrides, oxides, or borides. 
     
     
         3 . The method of making a rotary drill bit of  claim 1 , wherein the matrix materials comprise cobalt-based alloys, iron-based alloys, nickel-based alloys, cobalt and nickel-based alloys, iron and nickel-based alloys, iron and cobalt-based alloys, aluminum-based alloys, copper-based alloys, magnesium-based alloys or titanium-based alloys. 
     
     
         4 . The method of making a rotary drill bit of  claim 1 , further comprising inserting a blank into the mold such that upon cooling a lower portion of the blank is metallurgically bonded to the second region. 
     
     
         5 . The method of making a rotary drill bit of  claim 4 , further comprising attaching an upper portion of the steel blank to a bit body portion of a shank. 
     
     
         6 . The method of making a rotary drill bit of  claim 1 , wherein the bit body portion of the shank has one of a recessed portion or a protruding portion and the second region has one of a mating protruding portion or recessed portion, respectively, such that the protruding portion is configured to matingly engage the recessed portion, further comprising attaching the shank to the bit body portion by at least one of a weld joint, braze joint, threaded joint, adhesive joint or pinned joint using one or more attachment pins, or any combination thereof. 
     
     
         7 . The method of making a rotary drill bit of  claim 1 , further comprising casting a third region extending from and integrally formed with the second region within the mold after infiltrating the third region with a molten metal comprising cobalt-based alloys, iron-based alloys, nickel-based alloys, cobalt and nickel-based alloys, iron and nickel-based alloys, iron and cobalt-based alloys, aluminum-based alloys, copper-based alloys, magnesium-based alloys or titanium-based alloys, wherein the third region has a cast microstructure. 
     
     
         8 . The method of making a rotary drill bit of  claim 7 , wherein a plurality of hard particles are dispersed throughout the metal as a matrix, the hard particles comprise diamond, boron carbide, boron nitride, aluminum nitride, metal carbides or metal borides, and wherein casting the third region also comprises infiltrating a particle precursor of the third region with the molten metal as a third matrix material following infiltrating the second region. 
     
     
         9 . The method of making a rotary drill bit of  claim 7 , wherein the third region comprises a shank. 
     
     
         10 . The method of making a rotary drill bit of  claim 1 , wherein cooling the molten first particle-matrix mixture and the molten second particle-matrix mixture to solidify the first matrix material and the second matrix material and form the first particle-matrix composite material and the second particle-matrix composite is operative to form a plurality of dendrites in one of them. 
     
     
         11 . The method of making a rotary drill bit of  claim 1 , wherein the matrix of the first material composition and the matrix of the second material composition have substantially no solid solubility, and infiltrating the matrix of the first material composition and infiltrating the matrix of the second material composition forms an interface between them with substantially no interdiffusion of the matrix materials. 
     
     
         12 . The method of making a rotary drill bit of  claim 1 , wherein the matrix of the first material composition and the matrix of the second material composition have at least limited solid solubility, and infiltrating the matrix of the first material composition and infiltrating the matrix of the second material composition forms an interface between them comprising one of a solid solution, or a plurality of phases comprising constituents of the first material composition and the second material composition, having a predetermined thickness and a cast microstructure. 
     
     
         13 . A method of making an earth-boring rotary drill bit comprising a bit body having a first region configured to carry a plurality of cutters for engaging a subterranean earth formation and a second region configured for attachment to a drill string, comprising:
 providing a plurality of hard particles in a mold to define a particle precursor of the first region and the second region;   infiltrating the particle precursor sequentially with a plurality of molten matrix materials to form a corresponding plurality of layers, each comprising a particle-matrix mixture; and   cooling the plurality of particle-matrix mixtures to solidify the matrix materials and form a bit body comprising a plurality of particle-matrix composite materials.   
     
     
         14 . The method of making a rotary drill bit of  claim 13 , further comprising inserting a blank into the mold such that upon cooling a lower portion of the blank is metallurgically bonded to a plurality of the plurality of particle-matrix composite materials. 
     
     
         15 . The method of making a rotary drill bit of  claim 14 , further comprising attaching an upper portion of the steel blank to a bit body portion of a shank. 
     
     
         16 . The method of making a rotary drill bit of  claim 13 , wherein the bit body portion of the shank has one of a recessed portion or a protruding portion and the second region has one of a mating protruding portion or recessed portion, respectively, such that the protruding portion is configured to matingly engage the recessed portion, further comprising attaching the shank to the bit body portion by at least one of a weld joint, braze joint, threaded joint, adhesive joint or pinned joint using one or more attachment pins, or any combination thereof. 
     
     
         17 . The method of making a rotary drill bit of  claim 13 , further comprising casting a third region extending from and integrally formed with the second region within the mold after infiltrating the third region with a molten metal comprising cobalt-based alloys, iron-based alloys, nickel-based alloys, cobalt and nickel-based alloys, iron and nickel-based alloys, iron and cobalt-based alloys, aluminum-based alloys, copper-based alloys, magnesium-based alloys or titanium-based alloys, wherein the third region has a cast microstructure. 
     
     
         18 . The method of making a rotary drill bit of  claim 17 , wherein a plurality of hard particles are dispersed throughout the metal as a matrix, the hard particles comprise diamond, boron carbide, boron nitride, aluminum nitride, metal carbides or metal borides, and wherein casting the third region also comprises infiltrating a particle precursor of the third region with the molten metal as a third matrix material following infiltrating the second region. 
     
     
         19 . The method of making a rotary drill bit of  claim 13 , wherein the third region comprises a shank. 
     
     
         20 . The method of making a rotary drill bit of  claim 13 , wherein cooling the plurality of molten particle-matrix mixtures to solidify the plurality of matrix materials and form the plurality of particle-matrix composites is operative to form a plurality of dendrites in one of them.