Abstract: A welding rod for use in applying hardfacing to a surface of a tool includes an elongated, generally cylindrical body including a metal matrix material. The welding rod also includes particles of polycrystalline diamond material carried by the elongated, generally cylindrical body. The particles of polycrystalline diamond material include a plurality of inter-bonded diamond grains.

Abstract: Cutting elements, earth-boring drill bits having such cutting elements and related methods are described herein. In some embodiments, a cutting element for an earth-boring tool may include a diamond table having an indentation in a cutting face thereof and a shaped feature in a substrate at the interface between the diamond table and the substrate, the shaped feature corresponding to the indentation in the cutting face of the diamond table. In further embodiments, a cutting element for an earth-boring tool may include a sacrificial structure positioned within an indentation in a diamond table. In additional embodiments, a method of forming a cutting element may include positioning a sacrificial structure in a mold, positioning a powdered precursor material over the sacrificial structure, and pressing and sintering the powdered precursor material to form a diamond table having an indentation in a cutting face formed by the sacrificial structure.

Abstract: Cutting elements, earth-boring drill bits having such cutting elements and related methods are described herein. In some embodiments, a cutting element for an earth-boring tool may include a diamond table having an indentation in a cutting face thereof and a shaped feature in a substrate at the interface between the diamond table and the substrate, the shaped feature corresponding to the indentation in the cutting face of the diamond table. In further embodiments, a cutting element for an earth-boring tool may include a sacrificial structure positioned within an indentation in a diamond table. In additional embodiments, a method of forming a cutting element may include positioning a sacrificial structure in a mold, positioning a powdered precursor material over the sacrificial structure, and pressing and sintering the powdered precursor material to form a diamond table having an indentation in a cutting face formed by the sacrificial structure.

Abstract: Cutting structures for use with downhole tools in subterranean boreholes include a blade, a plurality of primary cutting elements coupled to the blade, and at least one secondary element rotationally leading the plurality of primary cutting elements in a direction of intended rotation of the cutting structure. The at least one secondary element is coupled to the blade proximate a leading surface of the blade and comprises at least one of a rubbing surface and a cutting surface. An exposure of at least one primary cutting element of the plurality of primary cutting elements is greater than an exposure of the at least one secondary element. Downhole tools such as reamers include cutting structures. Methods of enlarging a subterranean borehole include reaming a borehole with cutting structures.

Abstract: Cutting elements for use in earth-boring applications include a substrate, a transition layer, and a working layer. The transition layer and the working layer comprise a continuous matrix phase and a discontinuous diamond phase dispersed throughout the matrix phase. The concentration of diamond in the working layer is higher than in the transition layer. Earth-boring tools include at least one such cutting element. Methods of making cutting elements and earth-boring tools include mixing diamond crystals with matrix particles to form a mixture. The mixture is formulated in such a manner as to cause the diamond crystals to comprise about 50% or more by volume of the solid matter in the mixture. The mixture is sintered to form a working layer of a cutting element that is at least substantially free of polycrystalline diamond material and that includes the diamond crystals dispersed within a continuous matrix phase formed from the matrix particles.

Abstract: Earth-boring tools include combinations of shearing cutting elements and gouging cutting elements on a blade of the earth-boring tools. In some embodiments, a gouging cutting element may be disposed adjacent to a shearing cutting element on a blade of an earth-boring tool. Methods of forming earth-boring tools include providing such combination of at least one shearing cutting element and at least one gouging cutting element on a blade of an earth-boring tool.

Abstract: A cutting element for an earth-boring tool includes at least one volume of superabrasive material on a substrate. The volume of superabrasive material includes a first planar surface and a second planar surface oriented at an angle relative to the first planar surface and intersecting the first planar surface along an apex. The first planar surface has a circular or oval shape having a first maximum diameter, and the second planar surface has a circular or oval shape having a second maximum diameter. The apex has a length less than the first maximum diameter and the second maximum diameter. Earth-boring tools includes such a cutting element attached to a body. Methods of forming earth-boring tools include the attachment of such a cutting element to a body of an earth-boring tool.

Abstract: Cutting elements for earth-boring tools include one or more recesses and/or one or more protrusions in a cutting face of a volume of superabrasive material. The superabrasive material may be disposed on a substrate. The cutting face may be non-planar. The recesses and/or protrusions may include one or more linear segments. The recesses and/or protrusions may comprise discrete features that are laterally isolated from one another. The recesses and/or protrusions may have a helical configuration. The volume of superabrasive material may comprise a plurality of thin layers, at least two of which may differ in at least one characteristic. Methods of forming cutting elements include the formation of such recesses and/or protrusions in and/or on a cutting face of a volume of superabrasive material. Earth-boring tools include such cutting elements, and methods of forming earth-boring tools include attaching such a cutting element to a tool body.

Abstract: Methods of forming a hardfacing material include subjecting diamond grains to elevated temperatures and pressures to form diamond-to-diamond bonds between the diamond grains and form a PCD material. The PCD material is broken down to form PCD particles that include a plurality of inter-bonded diamond grains.

Abstract: Cutting elements for use in earth-boring applications include a substrate, a transition layer, and a working layer. The transition layer and the working layer comprise a continuous matrix phase and a discontinuous diamond phase dispersed throughout the matrix phase. The concentration of diamond in the working layer is higher than in the transition layer. Earth-boring tools include at least one such cutting element. Methods of making cutting elements and earth-boring tools include mixing diamond crystals with matrix particles to form a mixture. The mixture is formulated in such a manner as cause the diamond crystals to comprise about 50% or more by volume of the solid matter in the mixture. The mixture is sintered to form a working layer of a cutting element that is at least substantially free of polycrystalline diamond material and that includes the diamond crystals dispersed within a continuous matrix phase formed from the matrix particles.

Abstract: Methods of forming cutting element pockets in earth-boring tools may include forming a first recess and a second recess. A filler material is disposed in the second recess to the form at least a portion of a back surface of the pocket. Methods of forming cutting element pockets in earth-boring tools may include orienting a rotating cutter generally parallel to a longitudinal axis of a cutting element pocket to be formed in a body of an earth-boring tool and machining the cutting element pocket in the earth-boring tool. Methods of forming earth-boring tools include forming a body comprising at least one blade and forming at least one cutting element pocket in the at least one blade.

Abstract: Methods of forming bit bodies for earth-boring bits include assembling green components, brown components, or fully sintered components, and sintering the assembled components. Other methods include isostatically pressing a powder to form a green body substantially composed of a particle-matrix composite material, and sintering the green body to provide a bit body having a desired final density. Methods of forming earth-boring bits include providing a bit body substantially formed of a particle-matrix composite material and attaching a shank to the body. The body is provided by pressing a powder to form a green body and sintering the green body. Earth-boring bits include a unitary structure substantially formed of a particle-matrix composite material. The unitary structure includes a first region configured to carry cutters and a second region that includes a threaded pin. Earth-boring bits include a shank attached directly to a body substantially formed of a particle-matrix composite material.

Abstract: Earth-boring drill bits comprise a bit body having a plurality of radially extending blades and a plurality of cutting elements attached to the plurality of radially extending blades. Only gouging cutting elements are attached to at least one blade of the plurality of radially extending blades. Only shearing cutting elements are attached to at least another blade of the plurality of radially extending blades. Only shearing cutting elements are attached to a number of blades of the plurality of radially extending blades that is different from a number of blades of the plurality of radially extending blades to which only gouging cutting elements are attached. Methods of forming an earth-boring drill bit comprise forming a bit body including a plurality of radially extending blades. Only shearing cutting elements are attached to a number of blades different from a number of blades to which only gouging cutting elements are attached.

Abstract: Cutting elements for use in earth-boring applications include a substrate, a transition layer, and a working layer. The transition layer and the working layer comprise a continuous matrix phase and a discontinuous diamond phase dispersed throughout the matrix phase. The concentration of diamond in the working layer is higher than in the transition layer. Earth-boring tools include at least one such cutting element. Methods of making cutting elements and earth-boring tools include mixing diamond crystals with matrix particles to form a mixture. The mixture is formulated in such a manner as cause the diamond crystals to comprise about 50% or more by volume of the solid matter in the mixture. The mixture is sintered to form a working layer of a cutting element that is at least substantially free of polycrystalline diamond material and that includes the diamond crystals dispersed within a continuous matrix phase formed from the matrix particles.

Abstract: Methods for forming earth-boring tools include providing a metal or metal alloy bonding agent at an interface between a first element and a second element and sintering the first element, the second element, and the boding agent to form a bond between the first element and the second element at the interface. The methods may be used, for example, to bond together portions of a body of an earth-boring tool (which may facilitate, for example, the formation of cutting element pockets) or to bond cutting elements to a body of an earth-boring tool (e.g., a bit body of a fixed-cutter earth-boring drill bit or a cone of a roller cone earth-boring drill bit). At least partially formed earth-boring tools include a metal or metal alloy bonding agent at an interface between two or more elements, at least one of which may comprise a green or brown structure.

Abstract: Methods of forming polycrystalline diamond elements include forming a polycrystalline diamond compact comprising a cavity in a surface thereof. A catalyst is at least substantially removed from the polycrystalline diamond compact, and the polycrystalline diamond compact is secured to a supporting substrate. Cutting elements include a diamond table formed with a cavity in a back side surface thereof and a supporting substrate secured to the back side surface of the diamond table. Earth-boring tools comprise a bit body carrying one or more cutting elements including a diamond table, a supporting substrate and an adhesion layer comprising a superhard material between and bonding the cutting table and the supporting substrate.

Abstract: Methods of forming a polycrystalline table comprise disposing a plurality of particles comprising a superabrasive material, a substrate comprising a hard material, and a catalyst material in a mold. The plurality of particles is partially sintered in the presence of the catalyst material to form a brown polycrystalline table having a first permeability attached to an end of the substrate. The substrate is removed from the brown polycrystalline table and catalyst material is removed from the brown polycrystalline table. The brown polycrystalline table is then fully sintered to form a polycrystalline table having a reduced, second permeability. Intermediate structures formed during a process of attaching a polycrystalline table to a substrate comprising a substantially fully leached brown polycrystalline table. The substantially fully leached brown polycrystalline table comprises a plurality of interbonded grains of a superabrasive material.

Abstract: Methods of forming a polycrystalline element comprise forming a polycrystalline table on a first substrate. Catalyst material may be removed from at least a portion of the polycrystalline table. The polycrystalline table and a portion of a first substrate attached to the polycrystalline table may be removed from a remainder of the first substrate. The portion of the first substrate may be attached to another substrate. Polycrystalline elements comprise a polycrystalline table attached to a portion of a first substrate on which the polycrystalline table was formed another substrate attached to the portion of the first substrate.

Abstract: Polycrystalline elements comprise a substrate and a polycrystalline table attached to an end of the substrate. The polycrystalline table comprises a first region of superabrasive material having a first permeability and at least a second region of superabrasive material having a second, lesser permeability, the at least second region being interposed between the substrate and the first region. Methods of forming a polycrystalline element comprise attaching a polycrystalline table comprising a first region of superabrasive material having a first permeability and at least a second region of superabrasive material having a second, lesser permeability to an end of a substrate, the at least a second region being interposed between the first region and the substrate. Catalyst material is removed from at least the first region of the polycrystalline table.

Abstract: Cutting elements include a substrate, a thermally stable polycrystalline table comprising a superhard material secured to the substrate, and a layer of metal interposed between, and attaching the substrate and the thermally stable polycrystalline table. Methods of forming a cutting element include providing a thermally stable polycrystalline table in a mold, providing a layer of metal on the thermally stable polycrystalline table, distributing a mixture of particles comprising a plurality of hard particles and a plurality of particles comprising a matrix material on the layer of metal, and heating the mold while applying pressure to the mixture of particles to cause the mixture of particles to coalesce and form a substrate and at least partially melt the layer of metal to flow and wet the thermally stable polycrystalline table and the substrate to form an attachment therebetween.