A method of manufacturing polycrystalline abrasive elements consisting of micron, sub-micron or nano-sized ultrahard abrasives dispersed in micron, sub-micron or nano-sized matrix materials. A plurality of ultrahard abrasive particles having vitreophilic surfaces are coated with a matrix precursor material in a refined colloidal process and then treated to render them suitable for sintering. The matrix precursor material can be converted to an oxide, nitride, carbide, oxynitride, oxycarbide, or carbonitride, or an elemental form thereof. The coated ultrahard abrasive particles are consolidated and sintered at a pressure and temperature at which they are crystallographically or thermodynamically stable.

Embodiments of the invention relate to polycrystalline diamond compacts (“PDCs”) and methods of fabricating such PDCs. In an embodiment, a PDC includes a substrate and a preformed polycrystalline diamond table including an interfacial surface bonded to the substrate and an opposing working surface. The preformed polycrystalline diamond table includes a proximal region extending from the interfacial surface to an intermediate location within the preformed polycrystalline diamond table that includes a metallic infiltrant infiltrated from the substrate, and a distal region extending from the working surface to the intermediate location that is substantially free of the metallic infiltrant. A boundary exists between the proximal and distal regions that has a nonplanar irregular profile characteristic of the metallic infiltrant having been infiltrated into the preformed polycrystalline diamond table.

Embodiments of the invention relate to polycrystalline diamond compacts (“PDCs”) and methods of fabricating such PDCs. In an embodiment, a PDC includes a substrate and a preformed polycrystalline diamond table including an interfacial surface bonded to the substrate and an opposing working surface. The preformed polycrystalline diamond table includes a proximal region extending from the interfacial surface to an intermediate location within the preformed polycrystalline diamond table that includes a metallic infiltrant infiltrated from the substrate, and a distal region extending from the working surface to the intermediate location that is substantially free of the metallic infiltrant. A boundary exists between the proximal and distal regions that has a nonplanar irregular profile characteristic of the metallic infiltrant having been infiltrated into the preformed polycrystalline diamond table.

A method of forming a cutting element comprises forming a first material comprising discrete coated particles within a container. The first material is pressed to form a first green structure comprising interbonded coated particles. A second material comprising additional discrete coated particles is formed over the first green structure within the container. The second material is pressed to form a second green structure comprising additional interbonded coated particles. The first green structure and the second green structure are sintered to form a multi-layered cutting table. Additional methods of forming a cutting element, a cutting element, and an earth-boring tool are also described.

A method of forming a cutting element comprises forming a first material comprising discrete coated particles within a container. The first material is pressed to form a first green structure comprising interbonded coated particles. A second material comprising additional discrete coated particles is formed over the first green structure within the container. The second material is pressed to form a second green structure comprising additional interbonded coated particles. The first green structure and the second green structure are sintered to form a multi-layered cutting table. Additional methods of forming a cutting element, a cutting element, and an earth-boring tool are also described.

A fixed-cutter earth-boring tool includes a first blade substantially comprising a first material having a first elastic modulus at a temperature, and a second blade substantially comprising a second material having a second elastic modulus at the temperature. The second elastic modulus is different from the first elastic modulus. A method of forming an earth-boring tool includes forming a bit body having a plurality of blades, and providing at least one cutting element on at least one of the plurality of blades. Some fixed-cutter earth-boring drill bits include a first blade exhibiting a first deflection when subjected to a load, and a second blade exhibiting a second deflection when subjected to the load. The first deflection may be a continuous function of the load, and the second deflection may be a discontinuous function of the load.

A fixed-cutter earth-boring tool includes a first blade substantially comprising a first material having a first elastic modulus at a temperature, and a second blade substantially comprising a second material having a second elastic modulus at the temperature. The second elastic modulus is different from the first elastic modulus. A method of forming an earth-boring tool includes forming a bit body having a plurality of blades, and providing at least one cutting element on at least one of the plurality of blades. Some fixed-cutter earth-boring drill bits include a first blade exhibiting a first deflection when subjected to a load, and a second blade exhibiting a second deflection when subjected to the load. The first deflection may be a continuous function of the load, and the second deflection may be a discontinuous function of the load.

Embodiments relate to polycrystalline diamond compacts (“PDCs”) including a polycrystalline diamond (“PCD”) table in which a metal-solvent catalyst is alloyed with at least one alloying element to improve thermal stability of the PCD table. In an embodiment, a PDC includes a substrate and a PCD table bonded to the substrate. The PCD table includes diamond grains defining interstitial regions. The PCD table includes an alloy comprising at least one Group VIII metal and at least one metallic alloying element that lowers a temperature at which melting of the at least one Group VIII metal begins. The alloy includes one or more solid solution phases comprising the at least one Group VIII metal and the at least one metallic alloying element and one or more intermediate compounds comprising the at least one Group VIII metal and the at least one metallic alloying element.

Embodiments relate to polycrystalline diamond compacts (“PDCs”) including a polycrystalline diamond (“PCD”) table in which a metal-solvent catalyst is alloyed with at least one alloying element to improve thermal stability of the PCD table. In an embodiment, a PDC includes a substrate and a PCD table bonded to the substrate. The PCD table includes diamond grains defining interstitial regions. The PCD table includes an alloy comprising at least one Group VIII metal and at least one metallic alloying element that lowers a temperature at which melting of the at least one Group VIII metal begins. The alloy includes one or more solid solution phases comprising the at least one Group VIII metal and the at least one metallic alloying element and one or more intermediate compounds comprising the at least one Group VIII metal and the at least one metallic alloying element.

A hybrid drill bit includes a bit body having a plurality of fixed cutters disposed thereon and at least one rolling-cutter pocket. The hybrid drill bit further includes a rolling cutter rotatably positioned within the rolling-cutter pocket on the bit body. The rolling cutter includes a roller body with an axial bore and a plurality of teeth arranged around the roller body to engage a subterranean formation. Additionally, the hybrid drill bit includes a rolling cutter retention mechanism including a pin received within the axial bore of the rolling cutter, the pin engaging the bit body to rotatably couple the rolling cutter within the rolling-cutter pocket in the bit body.