Patent Publication Number: US-2021164295-A1

Title: Metal Matrix Compositions and Methods for Manufacturing Same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 15/111,851 filed Jul. 15, 2016, and entitled “Metal Matrix Compositions and Methods for Manufacturing Same,” which is a 35 U.S.C. § 371 national stage application of PCT/CN2016/080123 filed Apr. 25, 2016 and entitled, “Metal Matrix Compositions and Methods for Manufacturing Same,” which claims benefit of Chinese patent application Serial No. 201510887962.8 filed Dec. 7, 2015, and entitled “A Metal Matrix Composite and Its Additive Manufacturing Method,” each of which is hereby incorporated herein by reference in its entirety for all purposes. This application also claims benefit of PCT/CN2016/072748 filed Jan. 29, 2016, and entitled “A Metal Matrix Composite and Its Additive Manufacturing Method,” which is hereby incorporated herein by reference in its entirety for all purposes. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND 
     The disclosure relates generally to metal matrix compositions and methods for manufacturing such metal matrix compositions. More particularly, the disclosure relates to additive manufacturing methods for making metal matrix compositions and components made of such metal matrix compositions. 
     The metal matrix composites (MMCs) are composite materials formed of two or more constituents with at least one of the constituents being a metal. In general, the other constituent(s) can be metals or non-metals such as a ceramics or organic compounds. 
     MMCs are made by dispersing and embedding a reinforcing material into a continuous metal matrix. The metal matrix is often a relatively low-weight metal such as aluminum, magnesium, or titanium that provides a compliant support for the reinforcing material. In some high-temperature applications, the metal matrix is often made of cobalt or cobalt-nickel alloy. The reinforcing material can function to enhance the strength, wear resistance, or thermal conductivity of the metal matrix. For example, tungsten carbide (WC) can be used as a reinforcing material in an MMC to enhance the wear, erosion, corrosion, and impact resistance of the metal matrix within which it is embedded. MMCs utilizing tungsten carbide as a reinforcing material are employed in a variety of industrial applications and components. 
     BRIEF SUMMARY OF THE DISCLOSURE 
     Embodiments described herein include metal matrix composite compositions. In one embodiment a metal matrix composite composition comprises tungsten carbide in an amount of 45 wt % to 72 wt % of the composition. In addition, the metal matrix composite composition comprises a binder in an amount of 28 wt % to 55 wt % of the composition. The binder comprises nickel in an amount of at least 99 wt % of the binder. 
     Embodiments described herein comprise a combination of features and advantages intended to address various shortcomings associated with certain prior devices, systems, and methods. The foregoing has outlined rather broadly the features and technical advantages of the invention in order that the detailed description of the invention that follows may be better understood. The various characteristics described above, as well as other features, will be readily apparent to those skilled in the art upon reading the following detailed description, and by referring to the accompanying drawings. It should be appreciated by those skilled in the art that the conception and the specific embodiments disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a detailed description of the preferred embodiments of the invention, reference will now be made to the accompanying drawings in which: 
         FIG. 1  is a schematic view of an embodiment of an electron beam melting (EBM) machine for manufacturing embodiments of metal matrix composite components in accordance with the principles described herein; 
         FIG. 2  is a flowchart illustrating an embodiment of a method for manufacturing a metal matrix composite component in accordance with principles described herein; 
         FIG. 3  is a perspective top view of an embodiment of an earth-boring drill bit manufactured in accordance Example 3; 
         FIG. 4  is a partial side view of the drill bit of  FIG. 3 ; 
         FIG. 5  is an end view of the drill bit of  FIG. 3 ; 
         FIG. 6  is top view of an embodiment of a pump impeller manufactured in accordance with Example 4; 
         FIG. 7  is a side view of the pump impeller of  FIG. 6 ; and 
         FIG. 8  is a schematic cross-sectional view of an embodiment of a fluid conduit elbow manufactured in accordance with Example 5. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following discussion is directed to various exemplary embodiments. However, one skilled in the art will understand that the examples disclosed herein have broad application, and that the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to suggest that the scope of the disclosure, including the claims, is limited to that embodiment. 
     Certain terms are used throughout the following description and claims to refer to particular features or components. As one skilled in the art will appreciate, different persons may refer to the same feature or component by different names. This document does not intend to distinguish between components or features that differ in name but not function. The drawing figures are not necessarily to scale. Certain features and components herein may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in interest of clarity and conciseness. 
     In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . .” Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection, or through an indirect connection via other devices, components, and connections. In addition, as used herein, the terms “axial” and “axially” generally mean along or parallel to a central axis (e.g., central axis of a body or a part), while the terms “radial” and “radially” generally mean perpendicular to the central axis. For instance, an axial distance refers to a distance measured along or parallel to the central axis, and a radial distance means a distance measured perpendicular to the central axis. Still further, as used herein, the term “component” may be used to refer to a contiguous, single-piece or monolithic structure, part, or device. It is to be understood that a component may be used alone or as part of a larger system or assembly. 
     An earth-boring drill bit is typically mounted on the lower end of a drill string and is rotated by rotating the drill string at the surface and/or by a downhole motor. With weight applied to the drill string, the rotating bit engages the formation and drills a borehole through the formation. 
     Fixed cutter bits, also known as rotary drag bits, are a type of earth-boring drill bit that includes a bit body having a plurality of blades angularly spaced about a bit face and a plurality of cutter elements mounted on the blades. In general, the bit body can be made of steel or a hard metal cast matrix. A steel bit body is machined from a steel block or cylinder (i.e., via a material subtractive manufacturing process). A hardfacing material may subsequently be applied to the outer surface of the steel bit body via thermal spraying process before the cutter elements are secured in mating pockets on the blades via brazing. A matrix bit body is formed by a powdered metallurgical process. In particular, powdered tungsten carbide and a binder material such as Cu—Ni—Mn—Zn, Cu—Zn, or Cu—Ni—Mn—Sn are placed in a carbon/graphite mold. Typically, the powdered material placed in the mold (i.e., the tungsten carbide and the binder) has a composition comprising 50 wt % to 80 wt % tungsten carbide and 20 wt % to 50 wt % binder. The mold is then heated in a furnace to a temperature greater than 2,000° F. (greater than 1,100° C.) for about one hour to allow the binder material to infiltrate the tungsten carbide and form the solid metal matrix bit body. Next, the mold with the metal matrix bit body disposed therein is directionally cooled to room temperature, and then the mold is removed from the bit body by breaking, chiseling, and grinding the mold. This process for manufacturing metal matrix bit bodies can take more 24 hours to perform. 
     The cutter elements include an elongate and generally cylindrical tungsten carbide support member that is received and secured in a pocket formed in the surface of one of the several blades of the bit body (steel or metal matrix). A hard cutting layer of polycrystalline diamond (“PD”) or other superabrasive material (e.g., cubic boron nitride, thermally stable diamond, polycrystalline cubic boron nitride, etc.) is secured to the exposed end of the support member. 
     During drilling operations, a drill bit is subjected to extreme abrasive wear, impact loads, and thermal stresses. In some cases, the drill bit may also be exposed to corrosive fluids. Consequently, drill bits may experience severe wear, corrosion, and physical damage while drilling. For example, the bit body (steel or metal matrix) may be chipped or cracked due via impact with hard formations and rock. Sufficient damage to a drill bit may detrimentally reduce it cutting effectiveness and rate of penetration (ROP). In such cases, it may be necessary to change the drill bit by pulling the entire drillstring, which may be thousands of feet long, from the borehole section-by-section. Once the drill string has been retrieved and the new bit installed, the bit must be lowered to the bottom of the borehole on the drill string, which again must be constructed section-by-section. This process, referred to as a “trip” of the drillstring, requires considerable time, effort and expense. 
     A submersible pump is a pump having a sealed motor, which enables the pump to be completely submerged in the fluid to be pumped. Submersible pumps are often used in “artificial lift” applications to pump fluids (e.g., oil) in a borehole to the surface. Many submersible pumps are multistage centrifugal pumps, where each stage includes an impeller and a diffuser that directs fluid flow to the next stage of the pump. Well fluids pumped by submersible pumps typically comprise liquids containing solid particles entrained therein. The well fluids may also include corrosive liquids and/or gases. Consequently, during downhole pumping operations, the impellers experience abrasive wear, erosion, and may be exposed to corrosive fluids. As a result, continuous and extended rotation of the impellers in such well fluids may lead to abrasive wear, erosion, and corrosion, which may detrimentally alter the geometry of the impeller and ultimately shorten the operating life of the submersible pump. 
     Elbows are provided along conduits (e.g., pipelines) that transport fluids to change the direction of flow fluids. In some applications, the fluids flowing through conduits and elbows contain abrasive solid particles and/or corrosive fluids. As a result, flow of such fluids through an elbow over an extended period of time may lead to abrasive wear, erosion, and corrosion on the inner surfaces of the elbow, which may undesirably necessitate repair or replacement of the elbow. 
     As described above, many components and devices used in industrial processes such as earth-boring drill bits, pump impellers, and elbows along fluid conduits are subjected to impact loads, abrasive materials, corrosive fluids, or combinations thereof. Over time, such harsh operating conditions can leads to abrasive wear, erosion, corrosion, and damage to the particular component or device. Accordingly, it is desirable to employ materials and manufacturing techniques to produce components and devices that exhibit increased impact strength, wear resistance, and corrosion resistance to offer the potential to improve the operating lifetime of the components and devices. 
     One conventional approach to dealing with such challenges has focused on the use of carbide materials. For example, conventional earth-boring drill bits, submersible pump impellers, and elbows used along fluid conduits are often made of a steel alloy base material with one or more insert(s) of cemented carbide embedded in the surfaces that experience the harshest conditions and are most prone to damage. However, sufficient wear or damage to the base steel alloy surrounding the inserts can result in the loss of such inserts. Another approach to dealing with such challenges has focused on the application of hard metal coatings to the underlying base material to effectively protect the underlying base material. Typically, the coating is applied to the surfaces that experience the harshest conditions and are most prone to damage. However, differences in the physical properties of the underlying base material and the coating (e.g., differences in the coefficients of thermal expansion) can lead to de-bonding or cracking of the coating, which may ultimately lead to exposure of the underlying base material. 
     With particular regard to earth-boring drill bits having metal matrix bit bodies, reinforced tungsten carbide metal matrix composites has been the focus of most research and development aimed at enhancing impact strength, wear resistance, and corrosion resistance. As previously described, the powdered metallurgical process commonly used to produce such metal matrix bit bodies employs a powdered mixture of a binder material and tungsten carbide. The powdered mixture is pressed or injected in a mold and then sintered into a final product. Due to the use of a mold, the powdered mixtures limited ability to flow, and other constraints, it is difficult to produce components having complex shapes using the conventional powder metallurgical manufacturing processes. In addition, components produced using such conventional powder metallurgical manufacturing processes may include defects or develop cracks due to uneven heating during sintering or uneven cooling after sintering. Such defects and cracks may detrimentally reduce the wear resistance, erosion resistance, corrosion resistance, and impact strength of the produced component. 
     As will be described in more detail below, embodiments of metal matrix composite compositions and manufacturing methods disclosed herein offer the potential for materials and components with enhanced impact strength, wear resistance, erosion resistance, corrosion resistance, and operating lifetime. Such potential benefits may be achieved without the use of embedded inserts or the application of coatings. In addition, embodiments described herein also offer the potential to produce components having complex shapes and geometries via additive manufacturing methods that combine the use of powdered metallurgy and electron beam melting technologies. 
     Embodiments of manufacturing methods described herein utilize electron beam additive manufacturing techniques, also referred to as “electron beam melting” or simply “EBM.” In general, an EBM additive manufacturing process is a 3D printing technique that produces dense metal (or metal matrix composite) component by consolidating, via controlled and selective melting, a metal powder layer-by-layer into a solid mass using an electron beam as a heat source. The EBM additive manufacturing process is performed in and controlled by an EBM machine that reads data from a 3D CAD model, lays down successive layers of the powdered metal, and melts each successive layer (one at a time) with an electron beam to build up (i.e., “print”) the metal component layer-by-layer. Each layer is melted to the exact geometry defined by the 3D CAD model, and thus, enables the production of components with very complex geometries without tool, fixtures, or molds, and without producing any waste material. The EBM additive manufacturing process is performed under vacuum (i.e., at a pressure less than atmospheric) to enable use of metals and materials that exhibit a high affinity for oxygen (e.g., titanium), and at elevated temperatures. Examples of EBM machines that can perform EBM manufacturing processes include, without limitation, the Arcam A2X, the Arcam Q10, and the Arcam Q20, each available from Arcam AB of Molndal, Sweden. 
     Referring briefly to  FIG. 1 , an embodiment of an EBM machine  100  is shown. In general, EBM machine  100  can be used in embodiments of manufacturing methods disclosed herein such as additive manufacturing method  200  described in more detail below and shown in  FIG. 2 . In  FIG. 1 , EBM machine  100  is shown manufacturing an exemplary component  105 . In this embodiment, EBM machine  100  includes an electron beam column  110 , a vacuum chamber  120  coupled to column  110 , a plurality of hoppers  125  disposed in chamber  120 , a build tank  130  disposed in chamber  120 , a powder distribution device  126  disposed in chamber  120  between hoppers  125  proximal the top of build tank  130 , a start plate  140  disposed in tank  130 , and a build platform  150  moveably disposed in tank  130 . Electron beam column  110  includes a filament  111  that produces an electron beam  112 , a stigmator  113  to controllably reduce astigmatism of electron beam  112 , a focus lens or coil  114  to converge the electrons in beam  112  radially to form a focal spot  115 , and a deflection lens or coil  116  to change the direction or path of electron beam  112  and associated focal spot  115 . 
     Vacuum chamber  120  includes an outer housing  121  and an inner cavity  122  disposed within housing  121 . A vacuum (i.e., pressure less than atmospheric or ambient pressure) can be controllably applied to cavity  122 . Hoppers  125  disposed in cavity  122  store and feed a powdered mixture  127  used to form component  105 . As will be described in more detail below, the powdered mixture  127  is a homogenous mixture of a plurality of selected powdered source or raw materials. Accordingly, mixture  127  may also be referred to herein as powdered mixture  127  of selected source materials. Hoppers  125  feed the powdered mixture  127  onto a horizontal planar surface  128  in chamber  120 . A heat shield  129  extends downward from column  110  into cavity  122  between electron beam  112  and hoppers  125  to protect hoppers  125  and the powdered mixture  127  therein from electron beam  112 . 
     Referring still to  FIG. 1 , build tank  130  is a receptacle or cavity adjacent to and extending downwardly from surface  128 . Tank  130  is laterally positioned between hoppers  125 . In this embodiment, powder distribution device  126  is a rake that moves transversely within chamber  120  across surface  128  and the open top of build tank  130  (i.e., to the left and to the right in  FIG. 2 ) to distribute the powdered mixture  127  fed by hoppers  125  across build tank  130 . Platform  150  is moveably disposed in tank  130 . In particular, platform  150  can move vertically up and down within tank  130  to effectively decrease or increase the usably volume of tank  130 . In general, the dimensions tank  130  define the maximum dimensions of the component  105  that can be manufactured with EBM machine  100 . In embodiments described herein, build tank  130  preferably has a horizontal length greater than 200 mm, a horizontal width greater than 200 mm, and a vertical height (with platform  150  in its lowermost position) greater than 380 mm. A start plate  140  is positioned within tank  130  above platform  150  and functions as a sacrificial base onto which component  105  is built. 
     A control system (e.g., computer controlled system) and associated equipment (e.g., actuators, hardware, pumps, sensors, etc.) (not shown in  FIG. 1 ) are employed to control the operation of EBM machine  100 . A power supply system (not shown) provides power to the control system, EBM machine  100 , and related equipment. 
     To manufacture exemplary component  105 , start plate  140  is positioned at the top of build tank  130  by raising platform  150  and chamber  120  is evacuated. Next, hopper(s)  125  feed the powdered mixture  127  onto the surface  128  and rake  126  distributes a layer of the powdered mixture  127  onto start plate  140 . The control system (not shown) of EBM machine  100  reads data from a 3D CAD model to direct and control the operation of electron beam  112  to selectively and controllably melt the layer of the powdered mixture  127  to the exact geometry defined by the 3D CAD model. The portion of the powdered mixture  127  that is melted with electron beam  112  becomes a solid mass on start plate  140 . The platform  150  is then lowered approximately the thickness of the next layer of powdered mixture  127  to be added to the previously melted layer, rake  126  distributes the next layer of the powdered mixture  127  fed from hopper(s)  125  onto the previously melted layer, and the process is repeated to build-up component  105  layer-by-layer. During the manufacturing process, the electron beam  112  delivers sufficient power to the interface between beam  112  and powdered mixture at focal spot  115 , and is controllably moved linearly back-and-forth across the powdered mixture  127  at a suitable speed to sufficiently melt the layer of the powdered mixture  127 . 
     The powdered mixture  127  moved into tank  130  by device  126  that is not melted by electron beam  112  to form part of component  105  can collect in tank  130  around start plate  140  and component  150 . Such excess powdered mixture  127  can be removed from tank  130  after manufacture of component  105  and recycled for future use. 
     Referring now to  FIG. 2 , an embodiment of a method  200  for manufacturing a metal matrix composite component is shown. In this embodiment, method  200  is an electron beam additive manufacturing process. For purposes of clarity, method  200  is described below within the context of manufacturing exemplary metal matrix composite component  105  using EBM machine  100 , both as previously described. However, in general, method  200  can be used to manufacture (via electron beam additive manufacturing techniques) any metal matrix composite component, and further, EBM machines or systems other than EBM machine  100  can be used to perform embodiments of method  200 . 
     Beginning in block  201 , method  200  includes selecting the source materials or ingredients that are mixed together to form the powdered mixture  127 , which is ultimately melted into a single mass to form component  105 . As previously described, method  200  is an EBM additive manufacturing process, and thus, the source materials are in a powdered form suitable for forming powdered mixture  127  for use with EBM machine  100 . 
     In general, the type and relative amounts of the source materials determines the final composition of the component manufactured by the EBM additive manufacturing process. In other words, the composition of the component manufactured by the EBM additive manufacturing process (e.g., component  105  manufactured via method  200 ) is the same as the composition of the powdered mixture  127 , which is defined by the type and relative amounts of the source materials. In embodiments described herein, the manufactured component (e.g., component  105 ) is formed of a metal matrix composite having a composition comprising tungsten carbide uniformly distributed throughout a binder. Accordingly, the source materials comprise powdered tungsten carbide and a powdered binder. In embodiments described herein, the source materials preferably consist essentially of or consist of powdered tungsten carbide and powdered binder. As used herein, the phrases “consist(s) of” and “consisting of” are used to refer to exclusive components of a composition, meaning only those expressly recited components are included in the composition; whereas the phrases “consist(s) essentially of” and “consisting essentially of” are used to refer to the primary components of a composition, meaning that only small or trace amounts of components other than the expressly recited components (e.g., impurities, byproducts, etc.) may be included in the composition. For example, a composition consisting of X and Y refers to a composition that only includes X and Y, and thus, does not include any other components; and a composition consisting essentially of X and Y refers to a composition that primarily comprises X and Y, but may include small or trace amounts of components other than X and Y. In embodiments described herein, any such small or trace amounts of components other than those expressly recited following the phrase “consist(s) essentially of” or “consisting essentially of” preferably represent less than 5.0 wt % of the composition, more preferably less than 4.0 wt % of the composition, even more preferably less than 3.0 wt % of the composition, and still more preferably less than 1.0 wt % of the composition. 
     In embodiments described herein, the source materials preferably comprise powdered tungsten carbide in an amount of 45 wt % to 72 wt % of the powdered mixture  127  and a powdered binder in an amount of 28 wt % to 55 wt % of the powdered mixture  127  (i.e., the balance of the powdered mixture  127  is powdered binder); more preferably tungsten carbide in an amount of 50 wt % to 65 wt % of the powdered mixture  127  and powdered binder in an amount of 35 wt % to 50 wt % of the powdered mixture  127  (i.e., the balance of the powdered mixture  127  is powdered binder); and even more preferably tungsten carbide in an amount of 55 wt % to 60 wt % of the powdered mixture and powdered binder in an amount of 40 wt % to 45 wt % of the powdered mixture  127  (i.e., the balance of the powdered mixture is powdered binder). 
     In embodiments described herein, the powdered tungsten carbide can include spherical cast WC/W 2 C, angular cast WC/W 2 C, macro-crystalline WC, or combinations thereof. In general, spherical cast WC/W 2 C provides greater toughness than macro-crystalline WC and angular cast WC/W 2 C, spherical cast WC/W 2 C and angular cast WC/W 2 C have a greater hardness than macro-crystalline WC, and spherical cast WC/W 2 C exhibits reduced susceptibility to stress concentrations. Therefore, to optimize the hardness and toughness properties of the manufactured component, while reducing the potential for stress concentrations, spherical cast WC/W 2 C is preferred. Accordingly, in embodiments described herein, at least 50 vol % of the total powdered tungsten carbide in the source materials is preferably spherical cast WC/W 2 C, more preferably at least 60 vol % of the total powdered tungsten carbide (vol %) in the source materials is preferably spherical cast WC/WC, even more preferably at least 70 vol % of the total powdered tungsten carbide (vol %) in the source materials is preferably spherical cast WC/W 2 C, and still more preferably at least 80 vol % of the total powdered tungsten carbide (vol %) in the source materials is preferably spherical cast WC/W 2 C. 
     In embodiments described herein, the powdered tungsten carbide preferably has a powder mesh size (US Standard Sieve) of 50 mesh to 400 mesh (i.e., each of the tungsten carbide particles preferably has a size of 37.0 μm to 300.0 μm); more preferably 80 mesh to 400 mesh (i.e., each of the tungsten carbide particles preferably has a size of 37.0 μm to 180.0 μm); even more preferably 150 mesh to 350 mesh (i.e., each of the tungsten carbide particles preferably has a size of 43 μm to 100.0 μm); and still more preferably 200 mesh to 300 mesh (i.e., each of the tungsten carbide particles preferably has a size of 50.0 μm to 74.0 μm). 
     In embodiments described herein, the powdered binder preferably has a powder mesh size (US standard Sieve) of 60 mesh to 400 mesh (i.e., each of the particles in the binder has a size of 38.0 μm to 250.0 μm), more preferably 70 mesh to 325 mesh (i.e., each of the particles in the binder has a size of 45.0 μm to 212.0 μm), still more preferably 150 mesh to 350 mesh (i.e., each of the particles in the binder has a size of 43.0 μm to 100.0 μm), and even more preferably 200 mesh to 300 mesh (i.e., each of the particles in the binder has a size of 50.0 μm to 75.0 μm). 
     In embodiments described herein, the powdered binder source material is preferably a powdered nickel-based binder. More specifically, in embodiments described herein, the powdered binder source material preferably has a composition comprising boron (B), silicon (Si), and nickel (N). In addition, the powdered binder is preferably a relatively low melting point nickel-based binder. In particular, for use with EBM additive manufacturing processes, the powdered nickel-based binder preferably has a melting point less than 1250° C., more preferably between 600° C. and 1200° C., more preferably between 650° C. and 1100° C., even more preferably between 800° C. and 1000° C. 
     In embodiments described herein, the powdered binder preferably has a composition comprising Ni in an amount greater than 70 wt % of the powdered binder. More specifically, in embodiments described herein, the powdered binder preferably has a composition comprising B in an amount of 0 wt % to 6.0 wt % of the powdered binder, Si in an amount of 0 wt % to 6.0 wt % of the powdered binder, and Ni in an amount of at least 70 wt % of the powdered binder; more preferably the powdered binder has a composition comprising B in an amount of 0.5 wt % to 6.0 wt % of the powdered binder, Si in an amount of 2.0 wt % to 6.0 wt % of the powdered binder, and Ni in an amount of at least 70 wt % of the powdered binder; even more preferably the powdered binder has a composition comprising B in an amount of 1.0 wt % to 3.0 wt % of the powdered binder, Si in an amount of 2.5 wt % to 4.5 wt % of the powdered binder, and Ni in an amount of at least 90 wt % of the powdered binder, and still more preferably the powdered binder has a composition comprising B in an amount of 1.5 wt % to 2.5 wt % of the powdered binder, Si in an amount of 3.0 wt % to 4.0 wt % of the powdered binder, and Ni making up the entire balance of the powdered binder. 
     In some embodiments, other powdered materials such as chromium (Cr), iron (Fe), cobalt (Co), copper (Cu), molybdenum (Mo), phosphorus (P), aluminum (Al), niobium (Nb), titanium (Ti), manganese (Mn), or combinations thereof may be included in the powdered binder source material. In such embodiments including elements in addition to or as an alternative to one or more of B, Si, or Ni, the powdered binder preferably comprises Cr in an amount less than or equal to 23 wt % of the powdered binder, and more preferably an amount less than or equal to 7.0 wt % of the powdered binder, Fe in an amount of less than or equal to 3.0 wt % of the powdered binder; Co in an amount less than or equal to 22.0 wt % of the powdered binder; Cu in an amount less than or equal to 5.5 wt % of the powdered binder, Mo in an amount less than or equal to 1.5 wt % of the powdered binder; Pin an amount less than or equal to 2.0 wt % of the powdered binder. Al in an amount less than or equal to 0.4 wt %; Nb in an amount les than or equal to 4.15 wt %; Ti in an amount less than or equal to 0.05 wt %. The compositions of select exemplary powdered binders are provided in Table 1 below. 
     
       
         
           
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Exemplary 
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
                 Melting 
               
            
           
           
               
               
               
            
               
                 powdered 
                 Nominal Composition (wt. %) 
                 Point 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                 binder 
                 Cr 
                 Fe 
                 Si 
                 B 
                 Co 
                 Cu 
                 Mo 
                 P 
                 Al 
                 Nb 
                 Ti 
                 Mn 
                 Ni 
                 (° C.) 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                 1 
                 7.0 
                 3.0 
                 4.2 
                 3.0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 Balance 
                 999 
               
               
                 2 
                 0 
                 0 
                 4.5 
                 3.0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 Balance 
                 1030 
               
               
                 3 
                 0 
                 0 
                 3.5 
                 1.8 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 Balance 
                 1066 
               
               
                 4 
                 0 
                 0 
                 3.5 
                 2.8 
                 22.0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 Balance 
                 1129 
               
               
                 5 
                 3 
                 0 
                 2.5 
                 1.0 
                 0 
                 5.5 
                 1.5 
                 2.0 
                 0 
                 0 
                 0 
                 0 
                 Balance 
                 860 
               
               
                 6 
                 4.7 
                 1.8 
                 3.8 
                 2.6 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 Balance 
                 ~1000 
               
               
                 7 
                 20-23 
                 0.5 
                 0-0.5 
                   
                 0.1 
                   
                 8.0- 
                   
                 0.4 
                 3.15- 
                 0.04  
                 0.5 
                 Balance 
                 1290- 
               
               
                   
                   
                   
                   
                   
                   
                   
                 10.0 
                   
                   
                 4.15 
                   
                   
                   
                 1350 
               
               
                 8 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 100 
                 1455 
               
               
                   
               
            
           
         
       
     
     Referring again to  FIG. 2 , once the powdered source materials (i.e., the powdered tungsten carbide and the powdered binder) are selected in block  201 , the source materials are mixed together to form powdered mixture  127  in block  202 . The selected source materials are preferably mixed such that they are evenly and uniformly distributed throughout the resulting mixture  127  (i.e., powdered mixture  127  is preferably a homogeneous or substantially homogeneous mixture of the selected source materials). Moving now to block  203  powdered mixture  127  is loaded into hopper(s)  125  of EBM machine  100 . In addition, start plate  140  is positioned in build tank  130  according to block  204 . As described above, start plate  140  is the base that defines the surface on which component  105  is built. In general, start plate  140  can be made of any suitable metal or non-metal. Examples of suitable metals that can be used to form start plate  140  include, without limitation, nickel, iron, cobalt, aluminum, copper, titanium, and alloys thereof. Examples of suitable non-metals that can be used to form start plat  140  include, without limitation, ceramics, ceramics-metal composites such as SiC—Al 2 O 3 , Si 3 N 4 -M (where M is a metal), and carbide-graphite composites. In embodiments described herein, the start plate  140  is preferably made of a non-magnetic metal, carbon steel, or alloy steel. For manufacturing earth-boring drill bits as described in more detail below, the start plate  140  is preferably made of carbon steel or alloy steel. 
     With hopper(s)  125  loaded with powdered mixture  127  and start plate  140  disposed in build tank  130 , vacuum chamber  120  and electron beam column  110  of EBM machine  100  are evacuated in block  205 . In embodiments described herein, cavity  122  and electron beam column  110  are preferably evacuated to a pressure less than 8×10 −6  mBar. It should be appreciated that the actual pressure within the electron beam column  110  and vacuum chamber  120  may vary slightly. As an added precaution, cavity  122  is preferably purged with an inert gas such as nitrogen gas (N 2 ) or helium gas (He) during or immediately after it is evacuated to remove any gas(es) in cavity  122  that may react with the powdered mixture  127  or any of its constituents. 
     Referring still to  FIG. 2 , moving now to block  206 , the powdered mixture  127  is fed from hopper(s)  125  and a layer of the powdered mixture  127  is distributed on start plate  140  with device  126 . As previously described, device  126  moves transversely across the top of build tank  130  to move powdered mixture  127  fed from hopper(s) across start plate  140 . To facilitate consistent and uniform melting of the powdered mixture  127  with electron beam  112 , each layer of the powdered mixture  127  distributed by device  126  preferably has a uniform and constant thickness. More specifically, in embodiments described herein, each layer of the powdered mixture  127  distributed by device  126  preferably has a uniform and constant thickness of 0.04 mm and 0.12 mm, and more preferably 0.06 mm and 0.10 mm. 
     Next, in block  207 , electron beam column  110  generates electron beam  112  and controllably moves the focal spot  115  of beam  112  across the layer of the powdered mixture  127 . The electron beam  112 , via interface of the control system and a 3D CAD model of the component  105 , selectively melts the desired contour and profile of the layer of the powdered mixture  127  on start plate  140 . In particular, as the focal spot  115  continuously moves or sweeps linearly back-and-forth across the layer of the powdered mixture  127 , the portion of the powdered mixture  127  struck by focal spot  115  and the portions of the layer immediately adjacent the focal spot  115  are melted, and subsequently cool and solidify as the focal spot  115  continues it movement to an adjacent region of the layer. As the focal spot  115  sweeps across the layer of the powdered mixture  127 , successively adjacent portions of the layer are melted, cool, and solidify together, thereby controllably transitioning the layer of the powdered mixture  127  to a single, continuous, monolithic solid layer on start plate  140 . 
     In general, the power delivered by the electron beam  112  to the focal spot  115 , the width (or diameter) of the focal spot  115 , the line scanning speed of the focal spot  115  (i.e., the speed at which the focal spot  115  is moved linearly back-and-forth across the layer of the powdered mixture  127 ), and the scanning interval of the focal spot  115  (i.e., the horizontal distance measured center-to-center between each laterally adjacent linear pass of the focal spot  115  across the layer of the powdered mixture  127 ) are selected so that sufficient thermal energy is generated at the interface of electron beam  112  and the powdered mixture  127  to selectively melt the layer of the powdered mixture  127  into a single continuous homogenous monolithic mass. In embodiments described herein, the power delivered by the electron beam  112  to the focal spot  115  is preferably 200 W to 3000 W, more preferably 800 W to 2500 W, and even more preferably 1500 W to 2000 W; the focal spot  115  preferably has a width (or diameter) of 0.1 mm to 0.2 mm, more preferably 0.12 mm to 0.18 mm, and even more preferably 0.14 mm to 0.16 mm; the line scanning speed of the focal spot  115  is preferably 5.0 mm/s to 30.0 mm/s, more preferably 10.0 mm/s to 25.0 mm/s, and even more preferably 15.0 mm/s to 20.0 mm/s; and the scanning interval of the focal spot  115  is preferably 0.07 mm to 0.18 mm, and more preferably 0.10 mm to 0.15 mm. 
     Referring still to  FIG. 2 , after formation of the first or base layer of component  105  on start plate  140 , blocks  206 ,  207  are repeated to build component  105  layer by layer. As the focal spot  115  continuously moves or sweeps linearly back-and-forth across each successive layer of the powdered mixture  127 , the portion of the powdered mixture  127  struck by focal spot  115 , the portions of the layer immediately adjacent the focal spot  115 , and the portion of the upper surface of the previously deposited layer below the focal spot  115  are melted, and subsequently cooled and solidified together as the focal spot  115  continues it movement to an adjacent region of the layer. As the focal spot  115  sweeps across each successive layer of the powdered mixture  127 , successively adjacent portions of the layer are melted, cooled, and solidified together and with the previously deposited layer, thereby controllably transitioning the layer of the powdered mixture  127  and the previously deposited layer into a single-piece, continuous, monolithic solid mass. 
     In general, blocks  206 ,  207  are repeated until component  105  having the predetermined 3D shape is finished. The finished component  105  is a single-piece, continuous, monolithic solid mass having a uniform and homogenous composition throughout as defined by the composition of the powdered mixture  127 . In other words, the metal matrix composite composition of component  105  is the same as the composition of the powdered mixture  127  previously described. 
     As will be described in more detail below, embodiments of the metal matrix composite compositions described herein exhibit a relatively high hardness, wear resistance, corrosion resistance, compression strength, compression fracture distortion rate, and flexural strength (also referred to as bend strength or fracture strength). More specifically, embodiments of the metal matrix composite compositions described herein exhibit a hardness greater than 50 HRA (76 to 87 HRA), wear resistance of 75 to 85 times that of 42CrMo steel, a corrosion resistance of 25 to 32 times that of 316 stainless steel, a compression strength greater than 1700 Mpa, a compression fracture distortion rate greater than 12%, and a flexural strength of 1200 MPa to 1400 MPa (˜174 ksi to 203 ksi). Such physical properties offer the potential for improved strength, wear resistance, and corrosion resistance as compared to many conventional materials used to make components that experience impact loads, abrasive materials, corrosive fluids, or combinations thereof. 
     It should also be appreciated that embodiments of the metal matrix composite compositions described herein exhibit a homogeneous composition, uniform distribution of elements, and a uniform density throughout. These characteristics offer the potential for reduced susceptibility to cracking as compared to conventional metal matrix materials manufactured using conventional powder metallurgy techniques that often yield a less homogenous composition, non-uniform distribution of elements, and non-uniform density throughout. In addition, such characteristics (i.e., homogeneous composition, uniform distribution of elements, and a uniform density throughout) result in a relatively low composition micro-segregation and porosity. Still further, embodiments of additive manufacturing methods disclosed herein offer the potential to shorten the manufacturing cycle, reduce manufacturing costs, and improve the efficiency of the use of the source materials (i.e., reduce waste of the source materials) as compared to conventional powder metallurgy manufacturing techniques used to make metal matrix materials as embodiments described herein eliminate the steps of mold making, powder compacting, powder dispersion, sintering, infiltration, and precision machining. 
     In general, the embodiments of metal matrix composites compositions and manufacturing methods (e.g., method  200 ) disclosed herein can be used to make any type of component. As previously described, earth-boring drill bits, pump impellers, and elbows along fluid conduits may experience particularly problematic impact loads, abrasive materials, corrosive fluids, or combinations thereof. Over time, harsh operating conditions can leads to abrasive wear, erosion, corrosion, and damage to such components. In addition, many earth-boring drill bits, pump impellers, and fluid conduit elbows have relatively complex shapes that can be challenging to manufacture using conventional casting or molding methods. However, embodiments of metal matrix composites compositions and manufacturing methods disclosed herein offer the potential for earth-boring bits, pump impellers, and fluid conduit elbows with enhanced hardness, wear resistance, corrosion resistance, compression strength, compression fracture distortion rate, and flexural strength as compared to most conventional compositions and manufacturing methods. Such potential benefits may be achieved without the use of embedded inserts or the application of coatings. In addition, since embodiments of manufacturing methods described herein utilize EBM additive manufacturing techniques and do not use or rely on molds (e.g., pre-formed or pre-machined molds), such methods offer the potential to produce components having more complex shapes and geometries (e.g., structures with complex cavities, thin walled structures, etc.) than may be able to be made using most conventional manufacturing methods. Accordingly, the embodiments of metal matrix composites compositions and manufacturing methods disclosed herein may be particularly suitable for earth-boring drill bits, pump impellers, and fluid conduit elbows. 
     To further illustrate various illustrative embodiments of the present invention, the following examples are provided. 
     Example 1 
     A 10 mm×10 mm×10 mm cube-shaped test sample made of a metal matrix composite composition comprising 65 wt % WC, 0.63 wt % B, 1.23 wt % Si, 29.6 wt % Ni, and less than 0.1 wt % other element(s), was made in accordance with an embodiment of an EBM additive manufacturing method disclosed herein. The wear resistance of the test sample was determined according to China standard MLS-225B, GB/T 12444 entitled “Metallic materials-Wear tests Block-on-Ring Wear Test,” which utilizes a standard block-on-ring dry sliding friction test machine including a reference or standard comprising a 42CrMo steel ring. 
     The 42CrMo steel ring was quenched and tempered to a hardness of 53 HRC and rotated at a speed of 400 rev/min. The metal matrix composite sample was pressed against the rotating ring with a normal load of 20 Kgf for 60 minutes over a total sliding distance of 3800 m. For comparing the wear resistance of the metal matrix composite material to the 42CrMo steel, a relative wear resistance was define as follows: 
     
       
         
           
             
               Relative 
                
               
                   
               
                
               wear 
                
               
                   
               
                
               resistance 
             
             = 
             
               
                 Weight 
                  
                 
                     
                 
                  
                 loss 
                  
                 
                     
                 
                  
                 of 
                  
                 
                     
                 
                  
                 the 
                  
                 
                     
                 
                  
                 standard 
                  
                 
                     
                 
                  
                 due 
                  
                 
                     
                 
                  
                 to 
                  
                 
                     
                 
                  
                 frictional 
                  
                 
                     
                 
                  
                 wear 
               
               
                 Weight 
                  
                 
                     
                 
                  
                 loss 
                  
                 
                     
                 
                  
                 of 
                  
                 
                     
                 
                  
                 the 
                  
                 
                     
                 
                  
                 test 
                  
                 
                     
                 
                  
                 sample 
                  
                 
                     
                 
                  
                 due 
                  
                 
                     
                 
                  
                 to 
                  
                 
                     
                 
                  
                 frictional 
                  
                 
                     
                 
                  
                 wear 
               
             
           
         
       
     
     In this case, the “standard” was the 42CrMo steel ring and the “test sample” was the metal matrix composite sample. The calculated relative wear resistance results indicated that the wear resistance of the metal matrix composite material was 60 to 85 times greater than the wear resistance of the 42CrMo steel. 
     Example 2 
     A test sample made of a metal matrix composite composition comprising 72 wt % WC, 0.5 wt % B, 0.98 wt % Si, 26.42 wt % Ni, and less than 0.1 wt % other element(s) was made in accordance with an embodiment of an EBM additive manufacturing method disclosed herein. An immersed corrosion test was used to evaluate the corrosion resistance of the metal matrix composite test sample as compared to a reference or standard comprising a 316 stainless steel specimen. 
     The immersed corrosion test was carried out in 0.5 mol/L aqueous hydrochloric acid solution at 20° C. for 168 hours. For comparing the corrosion resistance of the metal matrix composite material to 316 stainless steel, a relative corrosion resistance was define as follows: 
     
       
         
           
             
               Relative 
                
               
                   
               
                
               corrosion 
                
               
                   
               
                
               resistance 
             
             = 
             
               
                 Weight 
                  
                 
                     
                 
                  
                 loss 
                  
                 
                     
                 
                  
                 of 
                  
                 
                     
                 
                  
                 the 
                  
                 
                     
                 
                  
                 standard 
                  
                 
                     
                 
                  
                 due 
                  
                 
                     
                 
                  
                 to 
                  
                 
                     
                 
                  
                 corrosion 
               
               
                 Weight 
                  
                 
                     
                 
                  
                 loss 
                  
                 
                     
                 
                  
                 of 
                  
                 
                     
                 
                  
                 the 
                  
                 
                     
                 
                  
                 test 
                  
                 
                     
                 
                  
                 sample 
                  
                 
                     
                 
                  
                 due 
                  
                 
                     
                 
                  
                 to 
                  
                 
                     
                 
                  
                 corrosion 
               
             
           
         
       
     
     In this case, the “standard” was the 316 stainless steel specimen and the“test sample” was the metal matrix composite sample. The calculated relative corrosion resistance results indicated that the corrosion resistance of the metal matrix composite material was 25 to 32 times greater than the corrosion resistance of the 316 stainless steel. 
     Example 3 
     A homogenous powdered mixture comprising 65 wt % of 80 mesh powdered tungsten carbide and 35 wt % of 150 mesh powdered nickel-based binder was prepared and placed in an EBM machine. The nickel-based binder comprised 0.54 wt % B, 1.05 wt % Si, 33.4 wt % Ni, and less than 0.1 wt % other element(s). The vacuum chamber of EBM machine was evacuated to 8×10−6 mBar and purged with nitrogen. Next, the powdered mixture was layered and selectively melted according to a 3D CAD model using an electron beam to additively manufacture an earth-boring drill bit  300  shown in  FIGS. 3-5 . The electron beam was delivered at a power of 1000 W to 1200 W, the width of the focal spot of the electron beam was 0.16 mm, the line scanning speed of the focal spot was 25 mm/s to 30 mm/s, the thickness of each layer of the powdered mixture was 0.1 mm, and the scanning interval of the electron beam was 0.1 mm. The drill bit  300  had a height of 82.37 mm and an outer diameter (or full gage diameter) of 82.37 mm. 
     The hardness, compression strength, compression fracture distortion rate, flexural strength, relative wear resistance, and relative corrosion resistance of the drill bit  300  were determined. In particular, the hardness was determined using a conventional Rockwell test, the compression strength and compression fracture distortion rate were determined in accordance with China standard GB/T7314-2005 entitled “Metallic Materials at Room Temperature Compression Test Method,” the flexural strength was determined in accordance with China standard GB/T 6569-86 entitled “Engineering Ceramics Bending Strength Test Method,” the relative wear resistance was determined according to the test procedure described above in Example 1, and the relative corrosion resistance was determined according to the test procedure described above in Example 2. The results were as follows: the hardness of the drill bit  300  was 78 HRA, the compression strength of the drill bit  300  was 1774 Mpa, the compression fracture distortion rate of the drill bit  300  was 14.3%, the flexural strength of the drill bit  300  was 1302 Mpa, the relative wear resistance of the drill bit  300  was 78.5 (i.e., 78.5 times greater than the wear resistance of the 42CrMo steel), and the relative corrosion resistance of the drill bit  300  was 28.4 (i.e., 28.4 times greater than the corrosion resistance of the 316 stainless steel). 
     As noted above, the hardness of the drill bit  300  made of an embodiment of a metal matrix composite composition disclosed herein and in accordance with an embodiment of an EBM additive manufacturing method disclosed herein was determined to be 78 HRA. For comparison purposes, a conventional matrix bit body was manufactured using conventional techniques (casting) and a powdered mixture comprising 70.0 wt % of 80.0 μm powdered tungsten carbide and 30.0 wt % of powdered copper based binder. The copper based binder comprised 53.0 wt % Cu, 23.0 wt % Mn, 15.0 wt % Ni, and 0.9 wt % Zn. The hardness of the conventional matrix bit body was determined to be 65-73 HRA. 
     As noted above the flexural strength of the drill bit  300  made of an embodiment of a metal matrix composite composition disclosed herein and in accordance with an embodiment of an EBM additive manufacturing method disclosed herein was determined to be 1,302 MPa (˜189 Ksi). In contrast, most conventional matrix bit bodies exhibit a flexural strength of about 758-930 MPa (˜110-135 Ksi). 
     Example 4 
     A homogenous powdered mixture comprising 70 wt % of 80 mesh powdered tungsten carbide and 30 wt % of 150 mesh powdered nickel-based binder was prepared and placed in an EBM machine. The nickel-based binder comprised 1.8 wt % B, 3.5 wt % Si, 94.6 wt % Ni, and less than 0.1 wt % other element(s). The vacuum chamber of EBM machine was evacuated to 8×10 −6  mBar and purged with nitrogen. Next, the powdered mixture was layered and selectively melted according to a 3D CAD model using an electron beam to additively manufacture a pump impeller  400  shown in  FIGS. 6 and 7 . The electron beam was delivered at a power of 2000 W to 2200 W, the width of the focal spot of the electron beam was 0.20 mm, the line scanning speed of the focal spot was 15 mm/s to 20 mm/s, the thickness of each layer of the powdered mixture was 0.12 mm, and the scanning interval of the electron beam was 0.15 mm. 
     The hardness, compression strength, compression fracture distortion rate, flexural strength, relative wear resistance, and relative corrosion resistance of the pump impeller  400  were determined. In particular, the hardness was determined using a conventional Rockwell test, the compression strength and compression fracture distortion rate were determined in accordance with China standard GB/T7314-2005 entitled “Metallic Materials at Room Temperature Compression Test Method,” the flexural strength/strength was determined in accordance with China standard GB/T 6569-86 entitled “Engineering Ceramics Bending Strength Test Method,” the relative wear resistance was determined according to the test procedure described above in Example 1, and the relative corrosion resistance was determined according to the test procedure described above in Example 2. The results were as follows: the hardness of the pump impeller  400  was 85.5 HRA, the compression strength of the pump impeller  400  was 1833 Mpa, the compression fracture distortion rate of the pump impeller  400  was 15.1%, the flexural strength of the pump impeller  400  was 1267 Mpa, the relative wear resistance of the pump impeller  400  was 82.7 (i.e., 82.7 times greater than the wear resistance of the 42CrMo steel), and the relative corrosion resistance of the pump impeller  400  was 30.7 (i.e., 30.7 times greater than the corrosion resistance of the 316 stainless steel). 
     Example 5 
     A homogenous powdered mixture comprising 72 wt % of 80 mesh powdered tungsten carbide and 28 wt % of 150 mesh powdered nickel-based binder was prepared and placed in an EBM machine. The nickel-based binder comprised 1.8 wt % B, 3.5 wt % Si, 94.6 wt % Ni, and less than 0.1 wt % other element(s). The vacuum chamber of EBM machine was evacuated to 8×10 −6  mBar and purged with nitrogen. Next, the powdered mixture was layered and selectively melted according to a 3D CAD model using an electron beam to additively manufacture a fluid conduit elbow  500  shown in  FIG. 8 . The electron beam was delivered at a power of 1500 W to 1800 W, the width of the focal spot of the electron beam was 0.18 mm, the line scanning speed of the focal spot was 15 mm/s to 20 mm/s, the thickness of each layer of the powdered mixture was 0.10 mm, and the scanning interval of the electron beam was 0.15 mm. 
     The hardness, compression strength, compression fracture distortion rate, flexural strength, relative wear resistance, and relative corrosion resistance of the elbow  500  were determined. In particular, the hardness was determined using a conventional Rockwell test, the compression strength and compression fracture distortion rate were determined in accordance with China standard GB/T7314-2005 entitled “Metallic Materials at Room Temperature Compression Test Method,” the flexural strength/strength was determined in accordance with China standard GB/T 6569-86 entitled “Engineering Ceramics Bending Strength Test Method,” the relative wear resistance was determined according to the test procedure described above in Example 1, and the relative corrosion resistance was determined according to the test procedure described above in Example 2. The results were as follows: the hardness of the elbow  500  was 82.5 HRA, the compression strength of the elbow  500  was 1873 Mpa, the compression fracture distortion rate of the elbow  500  was 14.1%, the flexural strength of the elbow  500  was 1291 Mpa, the relative wear resistance of the elbow  500  was 77.4 (i.e., 77.4 times greater than the wear resistance of the 42CrMo steel), and the relative corrosion resistance of the elbow  500  was 28.2 (i.e., 28.2 times greater than the corrosion resistance of the 316 stainless steel). 
     Example 6 
     A homogenous powdered mixture comprising 60 wt % of 100 mesh powdered tungsten carbide and 40 wt % of 125 mesh powdered nickel-based binder was prepared and placed in an EBM machine. The nickel-based binder was binder  5  in Table 1 above. Thus, the nickel-based binder comprised 1.0 wt % B, 2.5 wt % Si, 3.0 wt % Cr, 5.5 wt % Cu, 1.5 wt % Mo, 2.0 wt % P, and 84.5 wt % Ni. The vacuum chamber of EBM machine was evacuated to 8×10 −6  mBar and purged with helium. Next, the powdered mixture was layered and selectively melted according to a 3D CAD model using an electron beam to additively manufacture an earth-boring drill bit. The electron beam was delivered at a power of 920 W to 1100 W, the width of the focal spot of the electron beam was 0.14 mm, the line scanning speed of the focal spot was 28 mm/s to 35 mm/s, the thickness of each layer of the powdered mixture was 0.09 mm, and the scanning interval of the electron beam was 0.09 mm. 
     Example 7 
     A homogenous powdered mixture comprising 55 wt % of 120 mesh powdered tungsten carbide and 45 wt % of 125 mesh powdered nickel-based binder was prepared and placed in an EBM machine. The nickel-based binder was binder  1  in Table 1 above. Thus, the nickel-based binder comprised 3.0 wt % B, 4.2 wt % Si, 7.0 wt % Cr, 3.0 wt % Fe, and 82.8 wt % Ni. The vacuum chamber of EBM machine was evacuated to 8×10 −6  mBar and purged with helium. Next, the powdered mixture was layered and selectively melted according to a 3D CAD model using an electron beam to additively manufacture an earth-boring drill bit. The electron beam was delivered at a power of 850 W to 1040 W, the width of the focal spot of the electron beam was 0.12 mm, the line scanning speed of the focal spot was 30 mm/s to 38 mm/s, the thickness of each layer of the powdered mixture was 0.09 mm, and the scanning interval of the electron beam was 0.10 mm. 
     Example 8 
     A homogenous powdered mixture comprising 60 wt % of 100 mesh powdered tungsten carbide and 40 wt % of 125 mesh powdered nickel-based binder was prepared and placed in an EBM machine. The nickel-based binder was binder  2  in Table 1 above. Thus, the nickel-based binder comprised 3.0 wt % B, 4.5 wt % Si, and 92.5 wt % Ni. The vacuum chamber of EBM machine was evacuated to 8×10 −6  mBar and purged with helium. Next, the powdered mixture was layered and selectively melted according to a 3D CAD model using an electron beam to additively manufacture an earth-boring drill bit. The electron beam was delivered at a power of 900 W to 1050 W, the width of the focal spot of the electron beam was 0.13 mm, the line scanning speed of the focal spot was 32 mm/s to 40 mm/s, the thickness of each layer of the powdered mixture was 0.10 mm, and the scanning interval of the electron beam was 0.09 mm. 
     The hardness, compression strength, compression fracture distortion rate, flexural strength, relative wear resistance, and relative corrosion resistance of the drill bit were determined. In particular, the hardness was determined using a conventional Rockwell test, the compression strength and compression fracture distortion rate were determined in accordance with China standard GB/T7314-2005 entitled “Metallic Materials at Room Temperature Compression Test Method,” the flexural strength was determined in accordance with China standard GB/T 6569-86 entitled “Engineering Ceramics Bending Strength Test Method,” the relative wear resistance was determined according to the test procedure described above in Example 1, and the relative corrosion resistance was determined according to the test procedure described above in Example 2. The results were as follows: the hardness of the drill bit was 83.8 HRA, the compression strength of the drill bit was 1845 Mpa, the compression fracture distortion rate of the drill bit was 11.8%, the flexural strength of the drill bit was 1014 Mpa, the relative wear resistance of the drill bit was 61.4 (i.e., 61.4 times greater than the wear resistance of the 42CrMo steel), and the relative corrosion resistance of the drill bit was 42.1 (i.e., 42.1 times greater than the corrosion resistance of the 316 stainless steel). 
     Example 9 
     A homogenous powdered mixture comprising 65 wt % of 60 mesh powdered tungsten carbide and 35 wt % of 80 mesh powdered nickel-based binder was prepared and placed in an EBM machine. The nickel-based binder was binder  4  in Table 1 above. Thus, the nickel-based binder comprised 2.8 wt % B, 3.5 wt % Si, 22.0 wt % Co, and 71.7 wt % Ni. The vacuum chamber of EBM machine was evacuated to 8×10 −6  mBar and purged with helium. Next, the powdered mixture was layered and selectively melted according to a 3D CAD model using an electron beam to additively manufacture an earth-boring drill bit. The electron beam was delivered at a power of 1200 W to 1500 W, the width of the focal spot of the electron beam was 0.10 mm, the line scanning speed of the focal spot was 20 mm/s to 25 mm/s, the thickness of each layer of the powdered mixture was 0.18 mm, and the scanning interval of the electron beam was 0.12 mm. 
     The hardness, compression strength, compression fracture distortion rate, flexural strength, relative wear resistance, and relative corrosion resistance of the drill bit were determined. In particular, the hardness was determined using a conventional Rockwell test, the compression strength and compression fracture distortion rate were determined in accordance with China standard GB/T7314-2005 entitled “Metallic Materials at Room Temperature Compression Test Method,” the flexural strength was determined in accordance with China standard GB/T 6569-86 entitled “Engineering Ceramics Bending Strength Test Method,” the relative wear resistance was determined according to the test procedure described above in Example 1, and the relative corrosion resistance was determined according to the test procedure described above in Example 2. The results were as follows: the hardness of the drill bit was 79.5 HRA, the compression strength of the drill bit was 1584 Mpa, the compression fracture distortion rate of the drill bit was 13.1%, the flexural strength of the drill bit was 1108 Mpa, the relative wear resistance of the drill bit was 70.4 (i.e., 70.4 times greater than the wear resistance of the 42CrMo steel), and the relative corrosion resistance of the drill bit was 33.2 (i.e., 33.2 times greater than the corrosion resistance of the 316 stainless steel). 
     Example 10 
     A homogenous powdered mixture comprising 55 wt % of 120 mesh powdered tungsten carbide and 45 wt % of 125 mesh powdered nickel-based binder was prepared and placed in an EBM machine. The nickel-based binder was binder  3  in Table 1 above. Thus, the nickel-based binder comprised 1.8 wt % B, 3.5 wt % Si, and 94.7 wt % Ni. The vacuum chamber of EBM machine was evacuated to 8×10 −6  mBar and purged with helium. Next, the powdered mixture was layered on the surface of a 1018 carbon steel start plate and selectively melted according to a 3D CAD model using an electron beam to additively manufacture an earth-boring drill bit. The electron beam was delivered at a power of 850 W to 1040 W, the width of the focal spot of the electron beam was 0.12 mm, the line scanning speed of the focal spot was 30 mm/s to 38 mm/s, the thickness of each layer of the powdered mixture was 0.09 mm, and the scanning interval of the electron beam was 0.1 mm. 
     Example 11 
     Two homogenous powdered mixtures were made having the following compositions: (1) 40 wt % of 60 mesh powdered tungsten carbide and 60 wt % of 80 mesh powdered nickel-based binder; and (2) 60 wt % of 60 mesh powdered tungsten carbide and 40 wt % of 80 mesh powdered nickel binder, with the nickel binder comprising 100 wt % Ni. The nickel-based binder in the powdered mixture (1) was binder  7  in Table 1 above, and the nickel binder in the powdered mixture (2) was binder  8  in Table 1 above. Thus, the nickel-based powdered binder in mixture (1) comprised 20.0-23.0 wt % Cr, 0.5 wt % Fe, 0-0.5 wt % Si, 0.1 wt % Co, 8.0-10.0 wt % Mo, 0.4 wt % Al, 3.15-4.15 wt % Nb, 0.04 wt % Ti, and the balance being Ni; and the nickel binder in mixture (2) comprised 100 wt % Ni. 
     Each powder mixture was prepared and separately placed in an EBM machine to additively manufacture an earth-boring drill bit. In each case, the vacuum chamber of EBM machine was evacuated to 8×10 −6  mBar and purged with helium, and the powder mixture was layered and selectively melted according to a 3D CAD model using an electron beam. Further, in each case, the electron beam was delivered at a power of 1200 W to 1500 W, the width of the focal spot of the electron beam was 0.10 mm, the line scanning speed of the focal spot was 20 mm/s to 25 mm/s, the thickness of each layer of the powdered mixture was 0.18 mm, and the scanning interval of the electron beam was 0.12 mm. 
     The hardness and flexural strength of each drill bit was determined. In particular, the hardness was determined using a conventional Rockwell test and the flexural strength was determined in accordance with China standard GB/T 6569-86 entitled “Engineering Ceramics Bending Strength Test Method.” The results are shown in Table 2 below. 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Powdered Mixture 
                 Hardness (HRC) 
                 Flexural Strength (Ksi) 
               
               
                   
                   
               
             
            
               
                   
                 (1) 
                 45-62 
                 130-212 
               
               
                   
                 (2) 
                 32-50 
                 142-210 
               
               
                   
                   
               
            
           
         
       
     
     While preferred embodiments have been shown and described, modifications thereof can be made by one skilled in the art without departing from the scope or teachings herein. The embodiments described herein are exemplary only and are not limiting. Many variations and modifications of the systems, apparatus, and processes described herein are possible and are within the scope of the disclosure. For example, the relative dimensions of various parts, the materials from which the various parts are made, and other parameters can be varied. Accordingly, the scope of protection is not limited to the embodiments described herein, but is only limited by the claims that follow, the scope of which shall include all equivalents of the subject matter of the claims. Unless expressly stated otherwise, the steps in a method claim may be performed in any order. The recitation of identifiers such as (a), (b), (c) or (1), (2), (3) before steps in a method claim are not intended to and do not specify a particular order to the steps, but rather are used to simplify subsequent reference to such steps.