Polycrystalline compacts include a hard polycrystalline material comprising first and second regions. The first region comprises a first plurality of grains of hard material having a first average grain size, and a second plurality of grains of hard material having a second average grain size smaller than the first average grain size. The first region comprises catalyst material disposed in interstitial spaces between inter-bonded grains of hard material. Such interstitial spaces between grains of the hard material in the second region are at least substantially free of catalyst material. In some embodiments, the first region comprises a plurality of nanograins of the hard material. Cutting elements and earth-boring tools include such polycrystalline compacts. Methods of forming such polycrystalline compacts include removing catalyst material from interstitial spaces within a second region of a polycrystalline compact without entirely removing catalyst material from interstitial spaces within a first region of the compact.

Embodiments relate to polycrystalline diamond compacts (PDCs) and methods of manufacturing such PDCs in which an at least partially leached polycrystalline diamond (PCD) table is infiltrated with a low viscosity cobalt-based alloy infiltrant.

An aluminum-diamond composite that exhibits both high thermal conductivity and a coefficient of thermal expansion close to that of semiconductor devices, and that can suppress the occurrence of swelling, etc., of a surface metal layer portion even in actual use under a high load. An aluminum-diamond composite includes 65-80 vol % of a diamond powder having a roundness of at least 0.94, for which a first peak in a volumetric distribution of grain size lies at 5-25 m, and a second peak lies at 55-195 m, and a ratio between the area of the volumetric distribution of grain sizes of 1-35 m and the area of the volumetric distribution of grain sizes of 45-205 m is from 1:9 to 4:6; the balance being composed of a metal containing aluminum.

A cutting element includes a metallic carbide body, a first layer of polycrystalline diamond material, and at least one transition layer between the metallic carbide body and the first layer. The polycrystalline diamond material includes a plurality of interconnected diamond grains, first metal carbide particles, and a first binder material in interstitial regions between the interconnected first diamond grains, wherein the first metal carbide particles form a matrix in which the second diamond grains are dispersed and wherein the first metal carbide particles are present in the outer transition layer in an amount ranging from about 15 to 35 volume percent. The at least one transition layer includes a composite of diamond grains, second metal carbide particles, and a second binder material.

Embodiments relate to polycrystalline diamond compacts (PDCs) and methods of manufacturing such PDCs in which an at least partially leached polycrystalline diamond (PCD) table is infiltrated with a low viscosity cobalt-based alloy infiltrant.

A sintered body includes diamond particles and a binder. Each of the diamond particles has a boron concentration is 0.001 mass % to 0.1 mass %. The binder has a boron concentration of 0.01 mass % to 0.5 mass %.

Provided are a diamond composite material which is excellent in thermal conductivity, suitable as a material for a heat radiating member, and dense, the heat radiating member, and a method for producing a diamond composite material that can productively produce a diamond composite material which is excellent in wettability between diamond and metal and dense. The diamond composite material includes: a coated diamond particle including a diamond particle and a carbide layer covering a surface of the diamond particle and including an element of group 4 of the periodic table; and silver or a silver alloy binding such coated diamond particles together, with an oxygen content of 0.1 mass % or less.

A cubic boron nitride sintered material comprising cubic boron nitride grains and a binder, in which a content of the cubic boron nitride grains is no less than 30% by volume and no more than 80% by volume, the binder includes at least one selected from a second group consisting of a material made of a single element selected from a first group consisting of a group 4 element, a group 5 element and a group 6 element of the periodic table, aluminum, silicon, iron, cobalt and nickel, and an alloy and an intermetallic compound each composed of no less than two elements selected from the first group, and a content of a void in the cubic boron nitride sintered material is no less than 0.001% by volume and no more than 0.20% by volume.