Two-phase manufacture of metal matrix composites

Abstract

A method for fabricating a metal-matrix composite tool includes positioning an inner mold within an outer mold and thereby defining a gap between the inner and outer molds. A first reinforcement material is then loaded into the gap, and the first reinforcement material is infiltrated at a first temperature with a first binder material and thereby forming an outer shell. The inner mold is then removed and a second reinforcement material is loaded at least partially into the outer shell and infiltrated at a second temperature with a second binder material and thereby forming a reinforced composite material. The second temperature is lower than the first temperature and the second binder material is different than the first binder material. The outer shell is attached to exterior portions of the reinforced composite material.

What is claimed is: 
     
         1 . A method for fabricating a metal-matrix composite (MMC) tool, comprising:
 positioning an inner mold within an outer mold and thereby defining a gap between the inner and outer molds;   loading a first reinforcement material into the gap;   infiltrating the first reinforcement material at a first temperature with a first binder material and thereby forming an outer shell;   loading a second reinforcement material at least partially into the outer shell; and   infiltrating the second reinforcement material at a second temperature with a second binder material and thereby forming a reinforced composite material, wherein the second temperature is lower than the first temperature and the second binder material is different from the first binder material, and wherein the outer shell is attached to exterior portions of the reinforced composite material.   
     
     
         2 . The method of  claim 1 , further comprising varying a thickness of the gap and thereby varying a thickness of the outer shell at select regions. 
     
     
         3 . The method of  claim 1 , wherein positioning the inner mold within the outer mold further comprises positioning one or more displacements within the outer mold to form one or more features while infiltrating the first reinforcement material at the first temperature. 
     
     
         4 . The method of  claim 1 , wherein loading the second reinforcement material at least partially into the outer shell is preceded by positioning one or more displacements within the outer shell to form one or more features while infiltrating the second reinforcement material at the second temperature. 
     
     
         5 . The method of  claim 1 , wherein the outer mold is a first outer mold and wherein loading the second reinforcement material at least partially into the outer shell is preceded by:
 removing the outer shell from the first outer mold; and   positioning the outer shell in a second outer mold.   
     
     
         6 . The method of  claim 5 , wherein the second outer mold defines a plurality of cavities and a corresponding plurality of cutting elements are disposed in the plurality of cavities and alignable with a plurality of pockets defined in an outer surface of the outer shell, and wherein infiltrating the second reinforcement material at the second temperature further comprises attaching the plurality of cutting elements to the plurality of pockets. 
     
     
         7 . The method of  claim 6 , wherein an attachment material is disposed in the plurality of cavities with the plurality of cutting elements, and wherein attaching the plurality of cutting elements to the plurality of pockets comprises brazing the plurality of cutting elements to the plurality of pockets with the attachment material. 
     
     
         8 . The method of  claim 1 , wherein loading the second reinforcement material at least partially into the outer shell is preceded by depositing a material coating on at least a portion of an inner surface of the outer shell. 
     
     
         9 . The method of  claim 1 , wherein loading the second reinforcement material at least partially into the outer shell is preceded by forming one or more surface features on at least a portion of an inner surface of the outer shell. 
     
     
         10 . A metal-matrix composite (MMC) tool, comprising:
 a reinforced composite material forming a core of the MMC tool and having an exterior; and   an outer shell attached to at least a portion of the exterior and being harder than the reinforced composite material,   wherein the outer shell is formed during a first infiltration step where a first binder material infiltrates a first reinforcement material at a first temperature, the first reinforcement material being loaded into a gap defined between an inner mold and an outer mold,   wherein the reinforced composite portion is formed after the outer shell and during a second infiltration step where a second binder material infiltrates a second reinforcement material at a second temperature, the second reinforcement material being loaded at least partially into the outer shell, and   wherein the second temperature is lower than the first temperature and the second binder material is different from the first binder material.   
     
     
         11 . The MMC tool of  claim 10 , wherein the MMC tool is a tool selected from the group consisting of an oilfield drill bit or cutting tool, a non-retrievable drilling component, an aluminum drill bit body associated with casing drilling of wellbores, a drill-string stabilizer, a cone for roller-cone drill bits, a model for forging dies used to fabricate support arms for roller-cone drill bits, an arm for fixed reamers, an arm for expandable reamers, an internal component associated with expandable reamers, a sleeve attachable to an uphole end of a rotary drill bit, a rotary steering tool, a logging-while-drilling tool, a measurement-while-drilling tool, a side-wall coring tool, a fishing spear, a washover tool, a rotor, a stator and/or housing for downhole drilling motors, blades for downhole turbines, armor plating, an automotive component, a bicycle frame, a brake fin, an aerospace component, a turbopump component, and any combination thereof. 
     
     
         12 . The MMC tool of  claim 10 , wherein the first and second binder materials comprise a material selected from the group consisting of copper, nickel, cobalt, iron, aluminum, molybdenum, chromium, manganese, tin, zinc, lead, silicon, tungsten, boron, phosphorous, gold, silver, palladium, indium, any mixture thereof, any alloy thereof, and any combination thereof. 
     
     
         13 . The MMC tool of  claim 10 , wherein the first and second reinforcement materials comprise reinforcing particles selected from the group consisting of a metal, a metal alloy, a superalloy, an intermetallic, a boride, a carbide, a nitride, an oxide, a ceramic, a diamond, and any combination thereof. 
     
     
         14 . The MMC tool of  claim 10 , wherein a thickness of the outer shell varies. 
     
     
         15 . The MMC tool of  claim 10 , wherein the outer mold is a first outer mold and the outer shell is positioned in a second outer mold for the second infiltration step. 
     
     
         16 . The MMC tool of  claim 15 , wherein the second outer mold defines a plurality of cavities and a corresponding plurality of cutting elements and attachment material are disposable in the plurality of cavities and alignable with a plurality of pockets defined in an outer surface of the outer shell, and wherein the plurality of cutting elements are attached to the plurality of pockets during the second infiltration step. 
     
     
         17 . The MMC tool of  claim 10 , wherein a material coating is applied to at least a portion of an inner surface of the outer shell prior to loading the second reinforcement material at least partially into the outer shell. 
     
     
         18 . The MMC tool of  claim 17 , wherein the material coating comprises a material selected from the group consisting of a transition metal, a post-transition metal, a semi-metal, an alkaline-earth metal, a lanthanide, a non-metal, and any alloy thereof. 
     
     
         19 . The MMC tool of  claim 10 , wherein the MMC tool is a drill bit that defines one or more flow passageways and a fluid cavity, and wherein the outer shell extends along at least a portion of one or both of the one or more flow passageways and the fluid cavity. 
     
     
         20 . The MMC tool of  claim 10 , wherein the outer shell has an inner surface attached to the portion of the exterior of the reinforced composite material, and wherein the inner surface defines one or more surface features. 
     
     
         21 . The MMC tool of  claim 10 , wherein the MMC tool is a drill bit that provides a plurality of cutter blades, and wherein the outer shell comprises a plurality of component parts each positioned at a corresponding cutter blade. 
     
     
         22 . A drilling assembly, comprising:
 a drill bit attached to an end of a drill string; and   a pump fluidly connected to the drill string and configured to circulate a drilling fluid to the drill bit and through the wellbore, wherein the drill bit comprises:
 a reinforced composite material forming a core of the drill bit and having an exterior; and 
 an outer shell attached to at least a portion of the exterior and being harder than the reinforced composite material, 
 wherein the outer shell is formed during a first infiltration step where a first binder material infiltrates a first reinforcement material at a first temperature, the first reinforcement material being loaded into a gap defined between an inner mold and an outer mold, 
 wherein the reinforced composite portion is formed after the outer shell and during a second infiltration step where a second binder material infiltrates a second reinforcement material at a second temperature, the second reinforcement material being loaded at least partially into the outer shell, and 
 wherein the second temperature is lower than the first temperature and the second binder material is different from the first binder material. 
   
     
     
         23 . The drilling assembly of  claim 22 , wherein a thickness of the outer shell varies. 
     
     
         24 . The drilling assembly of  claim 22 ,
 wherein the outer mold is a first outer mold and the outer shell is positioned in a second outer mold for the second infiltration step,   wherein the second outer mold defines a plurality of cavities and a corresponding plurality of cutting elements and attachment material are disposable in the plurality of cavities and alignable with a plurality of pockets defined in an outer surface of the outer shell, and   wherein the plurality of cutting elements are attached to the plurality of pockets during the second infiltration step.   
     
     
         25 . The drilling assembly of  claim 22 , wherein a material coating is applied to at least a portion of an inner surface of the outer shell prior to loading the second reinforcement material at least partially into the outer shell. 
     
     
         26 . The drilling assembly of  claim 22 , wherein the drill bit defines one or more flow passageways and a fluid cavity, and wherein the outer shell extends along at least a portion of one or both of the one or more flow passageways and the fluid cavity. 
     
     
         27 . The drilling assembly of  claim 22 , wherein the drilling assembly is used in an offshore drilling system.