A method of providing well-shaped diamond grains of at most about 100 microns in size. The method includes providing a synthesis assembly comprising a source of carbon material, a plurality of seed grains on which diamond material can crystallize, and solvent-catalyst material for promoting the crystallization of the diamond grains, and subjecting the synthesis assembly to a condition for growing the diamond grains. The synthesis condition is maintained long enough for at least about half of the carbon material to be converted into the diamond grains.

A method of providing well-shaped diamond grains of at most about 100 microns in size. The method includes providing a synthesis assembly comprising a source of carbon material, a plurality of seed grains on which diamond material can crystallize, and solvent-catalyst material for promoting the crystallization of the diamond grains, and subjecting the synthesis assembly to a condition for growing the diamond grains. The synthesis condition is maintained long enough for at least about half of the carbon material to be converted into the diamond grains.

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.

Embodiments relate to a polycrystalline diamond compact (PDC) including a polycrystalline diamond (PCD) table having at least two regions and being bonded to a fine grained cemented tungsten carbide substrate. In an embodiment, a PDC includes a cemented carbide substrate having a cobalt-containing cementing constituent cementing tungsten carbide grains together that exhibit an average grain size of about 1.5 m or less, and a PCD table having at least one upper region including diamond grains exhibiting an upper average grain size and at least one lower region adjacent to the upper region a lower average grain size that may be at least two times greater than the upper average grain size. The cemented carbide substrate includes an interfacial surface and a depletion zone depleted of the cementing constituent that extends inwardly from the interfacial surface to a depth of, for example, about 30 m to about 60 m.

There is provided a metal-bonded grinding stone including an abrasive grain layer in which a plurality of abrasive grains and a plurality of pores are dispersed in a metal bonding material, in which a porosity of the plurality of pores in the abrasive grain layer is 40% or more and 99% or less.

Embodiments relate to polycrystalline diamond compacts (PDCs) including a substrate and a polycrystalline diamond (PCD) table mounted to the substrate. The PCD table includes an upper surface and one or more recesses extending inwardly from the upper surface of the PCD table. The one or more recesses may help prevent, stop, or limit crack propagation and may redistribute, breakup, or relieve stresses in the PCD table. In some embodiments, the one or more recesses exhibit, in plain view, a generally rectangular geometry, a generally circular geometry, or a generally triangular geometry. In some embodiments, the PCD table includes one or more channels that extend from a vertex of the one or more recesses. In some embodiments, the one or more channels and the one or more recesses may be at least partially filled with a sacrificial material. Methods for forming such PDCs are also discussed.

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 ?m) and at least one fraction of diamond particles with coarse particle size (15.0 to 30 ?m). During high pressurehigh 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.

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.

A fixed abrasive article having a body including abrasive particles contained within a bond material, the abrasive particles including shaped abrasive particles or elongated abrasive particles having an aspect ratio of length:width of at least 1.1:1, each of the shaped abrasive particles or elongated abrasive particles having a predetermined position or a predetermined three-axis orientation.

A fixed abrasive article having a body including abrasive particles contained within a bond material, the abrasive particles including shaped abrasive particles or elongated abrasive particles having an aspect ratio of length:width of at least 1.1:1, each of the shaped abrasive particles or elongated abrasive particles having a predetermined position or a predetermined three-axis orientation.