Embodiments relate to polycrystalline diamond compacts (PDCs) including a polycrystalline diamond (PCD) table having a diamond grain size distribution selected for improving performance and/or leachability. In an embodiment, a PDC includes a PCD table bonded to a substrate. The PCD table includes a plurality of diamond grains exhibiting diamond-to-diamond bonding therebetween. Other embodiments are directed to methods of forming PDCs, and various applications for such PDCs in rotary drill bits, bearing apparatuses, and wire-drawing dies.

Embodiments of the invention relate to methods of making articles having portions of polycrystalline diamond bonded to a surface of a substrate and polycrystalline diamond compacts made using the same. In an embodiment, a molding technique is disclosed for forming cutting tools comprising polycrystalline diamond portions bonded to the outer surface of a substrate.

A polycrystalline diamond compact (PDC), which is attached or bonded to a substrate to form a cutter for a drill bit, is comprised of sintered polycrystalline diamond interspersed with a seed material which has a hexagonal close packed (HCP) crystalline structure. A region of the sintered polycrystalline diamond structure, near one or more of its working surfaces, which has been seeded with an HCP seed material prior to sintering, is leached to remove catalyst. Selectively seeding portions or regions of a sintered polycrystalline diamond structure permits differing leach rates to form leached regions with differing distances or depths and geometries.

A polycrystalline compact includes a plurality of diamond grains of micron size, submicron size, or both, and a plurality of diamond nanoparticles disposed in interstitial spaces between the plurality of diamond grains. A method of forming a polycrystalline compact includes combining a plurality of micron and/or submicron-sized diamond grains and a plurality of diamond nanoparticles to form a mixture and sintering the mixture in a presence of a carburized binder to form a polycrystalline hard material having a plurality of inter-bonded diamond grains and diamond nanoparticles. Cutting elements including a polycrystalline compact and earth-boring tools bearing such compacts are also disclosed.

Methods of forming cutting elements may involve providing a thermally stable polycrystalline table and a substrate portion located adjacent to the thermally stable polycrystalline table in a mold. A metal material may be provided over the substrate portion on a side of the substrate portion opposing the thermally stable polycrystalline table in the mold, the metal material exhibiting a melting temperature of less than 1,320 C. A mixture of particles may be distributed on the metal material in the mold. The mold and its contents may be exposed to a temperature less than 1,320 C. and pressure may be applied to the mixture of particles to cause the mixture of particles to coalesce and form a substrate and to at least partially melt the metal material to flow, infiltrate the substrate portion, and wet the thermally stable polycrystalline table and the substrate to form an attachment therebetween.

A protective leaching cup includes a rear wall, an opening defined in a portion of the protective leaching cup opposite the rear wall, and a side wall extending between the opening and the rear wall, the side wall and the rear wall defining a cavity within the protective leaching cup. The side wall has a seal region adjacent the opening of the protective leaching cup, the seal region having a first inner diameter, and an encapsulating region extending between the seal region and the rear wall, the encapsulating region having a second inner diameter that is greater than the first inner diameter.

A cemented carbide body includes WC in a metallic binder phase. The cemented carbide body has a bulk portion and a surface portion. The grain size of the WC in the surface portion is smaller than the grain size in the bulk portion of the body and this gives an increased surface hardness and an increased wear resistance. The median grain thickness, tg, of WC in the surface portion is 20-300 nm and the average grain size in the bulk portion is 0.5-8 m. A method of surface hardening a cemented carbide body is also provided.

Polycrystalline compacts include an interface between first and second volumes of a body of inter-bonded grains of hard material. The first volume is at least substantially free of interstitial material, and the second volume includes interstitial material in interstitial spaces between surfaces of the inter-bonded grains of hard material. The interface between the first and second volumes is configured, located and oriented such that cracks originating in the compact during use of the compacts and propagating along the interface generally toward a central axis of the compacts will propagate generally toward a back surface and away from a front cutting face of the compacts at an acute angle or angles. Methods of forming polycrystalline compacts involve the formation of such an interface within the compacts.

Embodiments disclosed herein are directed to energy beam ablation machining methods that are used to machine polycrystalline diamond tables (e.g., polycrystalline diamond compacts that each includes polycrystalline diamond tables). Embodiments disclosed herein also are directed to polycrystalline diamond tables machined according to at least one of the energy beam ablation machining methods disclosed herein.

In an embodiment, a polycrystalline diamond compact (PDC) includes a substrate and a polycrystalline diamond (PCD) table bonded to the substrate. The PCD table includes an upper surface. The PCD table includes a first PCD region including bonded-together diamond grains and exhibits a first diamond density. At least a portion of the first PCD region extending inwardly from the working surface is substantially free of metal-solvent catalyst. The PCD table includes an intermediate second PCD region bonded to the substrate, which is disposed between the first PCD region and the substrate. The second PCD region includes bonded-together diamond grains defining interstitial regions, with at least a portion of the interstitial regions including metal-solvent catalyst disposed therein. The second PCD region exhibits a second diamond density that is greater than that of the first diamond density of the first PCD region.