Earth-boring metal matrix rotary drill bit

Abstract

An earth-boring rotary drill bit includes a bit body, with a first region configured to carry a plurality of cutters for engaging a subterranean earth formation of a first particle-matrix composite material and a second region configured for attachment to a drill string of a second particle-matrix composite material having a second material composition, and an annular shank extending from the second region. Each of the first particle-matrix composite material and second particle-matrix composite material has a cast microstructure. 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; 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 the bit body.

1 . An earth-boring rotary drill bit comprising:
 a bit body having a first region configured to carry one or more cutters for engaging a subterranean earth formation, the first region comprising a first particle-matrix composite material having a first material composition; and a second region configured for attachment to a drill string, the second region comprising a second particle-matrix composite material having a second material composition differing from the first material composition, each of the first particle-matrix composite material and second particle-matrix composite material substantially formed of a plurality of hard particles dispersed throughout a matrix material, wherein the matrix of the first particle-matrix composite and the matrix of the second particle-matrix composite each have a cast microstructure; and   a shank extending from the second region, the shank comprising an attachment portion configured to attach the shank to a drill string and a bit body portion for attaching the shank to the bit body.   
     
     
         2 . The rotary drill bit of  claim 1 , wherein the hard particles comprise diamond, or metal or semi-metal carbides, nitrides, oxides, or borides. 
     
     
         3 . The 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 and titanium-based alloys. 
     
     
         4 . The rotary drill bit of  claim 1 , wherein the matrix of the first material composition has a first melting temperature and the matrix of the second material composition has a second melting temperature and the first melting temperature and second melting temperature are different. 
     
     
         5 . The rotary drill bit of  claim 1 , wherein the first melting point is lower than the second melting point. 
     
     
         6 . The rotary drill bit of  claim 1 , wherein the first melting point is higher than the second melting point. 
     
     
         7 . The rotary drill bit of  claim 1 , wherein the matrix of the first material composition comprises a Cu-based alloy and the matrix of the second material composition comprises a Ni-based alloy. 
     
     
         8 . The rotary drill bit of  claim 1 , wherein the matrix of the first material composition comprises a Fe-based alloy and the matrix of the second material composition comprises a Cu-based alloy. 
     
     
         9 . The rotary drill bit of  claim 1 , wherein the matrix of the first material composition comprises a Cu-based alloy and the matrix of the second material composition comprises a Fe-based alloy. 
     
     
         10 . The rotary drill bit of  claim 1 , further comprising a steel blank having a lower portion that is metallurgically bonded to the second region and an upper portion that is attached to the bit body portion of the shank. 
     
     
         11 . The 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 protruding portion or a recessed portion, respectively, such that the recessed portion is configured to matingly engage and attach the protruding portion. 
     
     
         12 . The rotary drill bit of  claim 9 , wherein the recessed portion and the protruding portion are attached 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. 
     
     
         13 . The 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 have an interface between them with substantially no interdiffusion of the matrix materials. 
     
     
         14 . The 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 have an interface between them comprising one of a solid solution or a plurality of phases of the respective matrices having a predetermined thickness and a cast microstructure. 
     
     
         15 . The rotary drill bit of  claim 1 , further comprising a third region extending from and integrally formed with the second region, wherein the third region comprises 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 and titanium-based alloys. 
     
     
         16 . The rotary drill bit of  claim 15 , further comprising a plurality of hard particles dispersed throughout the metal as a matrix, wherein the hard particles comprise diamond, or metal or semi-metal, nitrides, oxides, or borides, and wherein the metal and hard particles comprise a third particle-matrix composite. 
     
     
         17 . The rotary drill bit of  claim 15 , wherein the third region comprises the shank. 
     
     
         18 . The rotary drill bit of  claim 1 , wherein the cast microstructure of at least one of the matrix of the first particle-matrix composite and the matrix of the second particle-matrix composite comprises a plurality of dendrites. 
     
     
         19 . An earth-boring rotary drill bit comprising:
 a bit body having a first region configured to carry one or more cutters for engaging a subterranean earth formation, the first region comprising a first particle-matrix composite material having a first material composition; and a second region configured for attachment to a drill string, the second region comprising a second particle-matrix composite material having a second material composition differing from the first material composition, each of the first particle-matrix composite material and second particle-matrix composite material substantially formed of a plurality of hard particles dispersed throughout a matrix material, wherein the matrix of the first particle-matrix composite and the matrix of the second particle-matrix composite each have a cast microstructure.   
     
     
         20 . An earth-rotary drill bit comprising:
 bit body having a first region configured to carry one or more cutters for engaging a subterranean earth formation, the first region comprising a first particle-matrix composite material having a first material composition, and a plurality of regions configured for attachment to a drill string, the plurality of regions comprising a corresponding plurality of particle-matrix composite materials having a corresponding plurality of material compositions differing from the first material composition, each of the first particle-matrix composite materials and plurality of additional particle-matrix composite materials substantially formed of a plurality of hard particles dispersed throughout a matrix material, wherein the matrix of the first particle-matrix composite and the plurality of additional particle-matrix composites each have a cast microstructure, and   a shank extending from at least one of the plurality of regions, the shank comprising an attachment portion configured to attach the shank to a drill string and a bit body portion for attaching the shank to a bit body.   
     
     
         21 . The rotary drill bit of  claim 20 , further comprising a steel blank having a lower portion that is metallurgically bonded to a plurality of the plurality of regions and an upper portion that is attached to the bit body portion of the shank.