Abstract: Methods of forming polycrystalline compacts include subjecting a plurality of grains of hard material interspersed with a catalyst material to high-temperature and high-pressure conditions to form a polycrystalline material having intergranular bonds and interstitial spaces between adjacent grains of the hard material. The catalyst material is disposed in at least some of the interstitial spaces in the polycrystalline material. The methods further comprise substantially removing the catalyst material from the interstitial spaces in at least a portion of the polycrystalline material to form an at least partially leached polycrystalline compact; and removing a portion of the polycrystalline material from which the catalyst material has been substantially removed from the at least partially leached polycrystalline compact. The polycrystalline cutting elements may be secured to a bit body of an earth-boring tool.

Abstract: Cutting elements for earth-boring tools may include a substrate and a polycrystalline superabrasive material secured to the substrate. The polycrystalline superabrasive material may include a first region including catalyst material in interstitial spaces among interbonded grains of the polycrystalline superabrasive material. A second region at least substantially free of catalyst material in the interstitial spaces among the interbonded grains of the polycrystalline superabrasive material may be located adjacent to the first region. An undulating boundary defined between the first region and the second region may extend from a longitudinal axis of the cutting element to a periphery of the cutting element.

Abstract: A cutting element configured to mitigate spalling on a front cutting face thereof. The cutting element include a diamond table having the front cutting face defined thereon and at least one recess defined on the front cutting face of the diamond table. The at least one recess has a width within a range of 25.0 ?m to 650 ?m and a depth within a range of 25.0 ?m to 600 ?m. Methods of forming a cutting element configured to mitigate spalling on the front cutting face thereof. The methods including forming at least one recess on a front cutting face of a diamond table to have a width within a range of 25.0 ?m to 650 ?m and a depth within a range of 25.0 ?m to 600 ?m. Method of using a cutting element configured to mitigate spalling on the front cutting face thereof.

Abstract: Methods of forming polycrystalline compacts include subjecting a plurality of grains of hard material interspersed with a catalyst material to high-temperature and high-pressure conditions to form a polycrystalline material having intergranular bonds and interstitial spaces between adjacent grains of the hard material. The catalyst material is disposed in at least some of the interstitial spaces in the polycrystalline material. The methods further comprise substantially removing the catalyst material from the interstitial spaces in at least a portion of the polycrystalline material to form an at least partially leached polycrystalline compact; and removing a portion of the polycrystalline material from which the catalyst material has been substantially removed from the at least partially leached polycrystalline compact. The polycrystalline cutting elements may be secured to a bit body of an earth-boring tool.

Abstract: A cutting element for an earth-boring tool includes a substrate and volume of superabrasive material positioned on the substrate. The volume of superabrasive material includes a cutting face having at least one recess extending into the volume of superabrasive material and/or at least one protrusion extending outward from the volume of superabrasive material. The volume of superabrasive material includes a first chamfer surface having a peripheral edge and a radially innermost edge. The peripheral edge of the first chamfer surface is located proximate a cutting edge of the volume of superabrasive material. A radial width of the first chamfer surface is between about 0.002 inch and about 0.045 inch. The volume of superabrasive material also includes a second chamfer surface having a peripheral edge and a radially innermost edge. The peripheral edge of the second chamfer surface is located adjacent the radially innermost edge of the first chamfer surface.

Abstract: An earth-boring tool includes a cutting element having a first volume of polycrystalline material including catalyst material and a second volume free of catalyst material. A boundary between the first volume and the second volume is nonlinear in a cross-sectional plane that includes a centerline of the cutting element and an anticipated point of contact of the cutting element with the surface of the formation to be cut. Each line tangent the boundary in the cross-sectional plane forms an angle with the centerline of the cutting element greater than the contact back rake angle of the cutting element. In some cutting elements, some portions of the boundary may have another selected shape. Some cutting elements have a boundary wherein tangent lines form angles of greater than 20° with the centerline of the cutting element. Methods of forming wellbores are also disclosed.

Abstract: Cutting elements for earth-boring tools may include a substrate and a polycrystalline superabrasive material secured to the substrate. The polycrystalline superabrasive material may include a first region including catalyst material in interstitial spaces among interbonded grains of the polycrystalline superabrasive material. A second region at least substantially free of catalyst material in the interstitial spaces among the interbonded grains of the polycrystalline superabrasive material may be located adjacent to the first region. An undulating boundary defined between the first region and the second region may extend from a longitudinal axis of the cutting element to a periphery of the cutting element.

Abstract: Polycrystalline diamond compact (PDC) cutting elements include leached and un-leached regions. The leached region may be or include a leached annular region. An inner boundary of the leached annular region remote from a side surface of the polycrystalline diamond may have a non-linear profile in a plane extending through the PDC cutting element along a longitudinal axis of the cutting element. Methods of forming PDC cutting elements include configuring polycrystalline diamond of a PDC cutting element to have such a leached annular region with a non-linear profile. Earth-boring tools may be formed that include such PDC cutting elements.

Abstract: Methods of forming polycrystalline compacts include subjecting a plurality of grains of hard material interspersed with a catalyst material to high-temperature and high-pressure conditions to form a polycrystalline material having intergranular bonds and interstitial spaces between adjacent grains of the hard material. The catalyst material is disposed in at least some of the interstitial spaces in the polycrystalline material. The methods further comprise substantially removing the catalyst material from the interstitial spaces in at least a portion of the polycrystalline material to form an at least partially leached polycrystalline compact; and removing a portion of the polycrystalline material from which the catalyst material has been substantially removed from the at least partially leached polycrystalline compact. The polycrystalline cutting elements may be secured to a bit body of an earth-boring tool.

Abstract: A cutting element may include a substrate and a volume of polycrystalline diamond material affixed to the substrate at an interface. The volume of polycrystalline diamond may include a front cutting face with at least one substantially planar portion and at least one recess. The at least one recess may extend from a plane defined by the at least one substantially planar portion a first depth into the volume of polycrystalline diamond material in an axial direction parallel to a central axis of the cutting element. The volume of polycrystalline diamond material may comprise a region including a catalyst material. At least one region substantially free of the catalyst material may extend from the at least one substantially planar portion of the front cutting face a second depth into the volume of polycrystalline diamond in the axial direction. Methods of forming cutting elements.

Abstract: Earth-boring drill bits include a bit body, an element having an attachment feature bonded to the bit body, and a shank assembly. Methods for assembling an earth-boring rotary drill bit include bonding a threaded element to the bit body of a drill bit and engaging the shank assembly to the threaded element. A nozzle assembly for an earth-boring rotary drill bit may include a cylindrical sleeve having a threaded surface and a threaded nozzle disposed at least partially in the cylindrical sleeve and engaged therewith. Methods of forming an earth-boring drill bit include providing a nozzle assembly including a tubular sleeve and nozzle at least partially within a nozzle port of a bit body.

Abstract: Earth-boring drill bits include a bit body, an element having an attachment feature bonded to the bit body, and a shank assembly. Methods for assembling an earth-boring rotary drill bit include bonding a threaded element to the bit body of a drill bit and engaging the shank assembly to the threaded element. A nozzle assembly for an earth-boring rotary drill bit may include a cylindrical sleeve having a threaded surface and a threaded nozzle disposed at least partially in the cylindrical sleeve and engaged therewith. Methods of forming an earth-boring drill bit include providing a nozzle assembly including a tubular sleeve and nozzle at least partially within a nozzle port of a bit body.

Abstract: Earth-boring drill bits include a bit body, an element having an attachment feature bonded to the bit body, and a shank assembly. Methods for assembling an earth-boring rotary drill bit include bonding a threaded element to the bit body of a drill bit and engaging the shank assembly to the threaded element. In additional embodiments, a nozzle assembly for an earth-boring rotary drill bit may include a cylindrical sleeve having a threaded surface and a threaded nozzle disposed at least partially in the cylindrical sleeve and engaged therewith. Methods of forming an earth-boring drill bit include providing a nozzle assembly including a tubular sleeve and nozzle at least partially within a nozzle port of a bit body.