Diamond bodies and methods of manufacture are disclosed. Diamond bodies are formed from at least a bimodal, alternatively a tri-modal or higher modal, feedstock having at least one fraction of modified diamond particles with a fine particle size (0.5-3.0 μm) and at least one fraction of diamond particles with coarse particle size (15.0 to 30 μm). During high pressure-high temperature processing, fine particle sized, modified diamond particles in the first fraction preferentially fracture to smaller sizes while preserving the morphology of coarse particle sized diamond particles in the second fraction. Diamond bodies incorporating the two fractions have a microstructure including second fraction diamond particles dispersed in a continuous matrix of first fraction modified diamond particles and exhibit improved wear characteristics, particularly for wear associated with drilling of geological formations.

A polycrystalline diamond compact including a cemented carbide substrate and a polycrystalline diamond layer bonded to the cemented carbide substrate. The polycrystalline diamond layer is nonplanar and includes a central part and a peripheral part surrounding the central part. The central part includes a protruding surface relative to the peripheral part. The protruding surface is spherical or planar. The peripheral part includes a plurality of radially-disposed ridges.

Provided is a method for producing a polycrystalline diamond body, the method including a first step of heat-treating a powder of high-pressure-phase carbon at higher than or equal to 1300° C. to obtain a heat-treated carbon powder, and a second step of sintering the heat-treated carbon powder under conditions of greater than or equal to 12 GPa and less than or equal to 25 GPa and higher than or equal to 1200° C. and lower than or equal to 2300° C. to obtain a polycrystalline diamond body.

A method of forming a composite cutter for a downhole drilling tool is described. The method includes: mixing a polycrystalline diamond powder and a cubic boron nitride powder with a molar ratio between 0.1 and 0.9 to form a catalyst-free composite mixture; placing the catalyst-free composite mixture into a mold configured in a shape of a cutter; exposing the catalyst-free composite mixture to an ultra-high-pressure, high-temperature treatment including a pressure between 11 Gigapascals (GPa) and 20 GPa, and a temperature between 1300 Kelvins (K) and 2600 K to form a solid composite body; and cooling the solid composite body to form the composite cutter.

A super hard polycrystalline construction is disclosed as comprising a body of super hard material bonded to a substrate. The body of super hard material comprises an outer peripheral region formed of interbonded grains of super hard material extending peripherally around one or more inner regions, the outer peripheral region having a radial thickness proportional to the square of the ratio of the fracture toughness of the material forming said outer peripheral region to the transverse rupture strength of the material forming said outer peripheral region (K.sub.IC/TRS).sup.2 where TRS is the transverse rupture strength and K.sub.IC is the fracture toughness.

A method of forming a supporting substrate for a cutting element comprises forming a precursor composition comprising discrete WC particles, a binding agent, and discrete particles comprising Co, Al, and one or more of C and W. The precursor composition is subjected to a consolidation process to form a consolidated structure including WC particles dispersed in a homogenized binder comprising Co, Al, W, and C. A method of forming a cutting element, a cutting element, a related structure, and an earth-boring tool are also described.

A method of making a thermally stable polycrystalline super hard construction having a plurality of interbonded super hard grains and interstitial regions disposed therebetween to form a polycrystalline super hard construction having a first thermally stable region and a second region, the first thermally stable region forming at least part of a working surface of the construction, comprises treating the polycrystalline super hard material with a leaching mixture to remove non-super hard phase material from a number of interstitial regions in the first region. The step of treating comprises masking the polycrystalline super hard construction along at least a portion of the peripheral side surface up to and/or at the working surface to inhibit penetration of the leaching mixture into the super hard construction through a peripheral side surface of the super hard construction.

Embodiments of the invention relate to polycrystalline diamond compacts (“PDCs”) and methods of fabricating polycrystalline diamond tables and PDCs in a manner that facilitates removal of metal-solvent catalyst used in the manufacture of polycrystalline diamond tables of such PDCs.

A polycrystalline diamond structure comprises a first region and a second region adjacent the first region, the second region being bonded to the first region by intergrowth of diamond grains. The first region comprises a plurality of alternating strata or layers, each or one or more strata or layers in the first region having a thickness in the range of around 5 to 300 microns. The polycrystalline diamond (PCD) structure has a diamond content of at most about 95 percent of the volume of the PCD material, a binder content of at least about 5 percent of the volume of the PCD material, and one or more of the layers or strata in the first region comprise and/or the second region comprises diamond grains having a mean diamond grain contiguity of greater than about 60 percent and a standard deviation of less than about 2.2 percent. There is also disclosed a method of making such a polycrystalline diamond structure.

Provided is a polycrystalline diamond cutter with a substrate and a diamond body in which the diamond body includes bonded diamond particles and discernable diamondene fragments. The polycrystalline diamond cutter is manufactured by a high pressure high temperature method that includes sintering a diamond feed layer in which the diamond feed layer includes diamond particles and diamondene fragments.