A cBN sintered body including cBN and a binder phase, wherein a content ratio of the cBN is 80 to 94 volume %, a content ratio of the binder phase is 6 to 20 volume %, the binder phase contains a metal phase, a V compound, and an Al compound, the metal phase contains one or more selected from the group consisting of Ni, and a Ni-containing alloy and solid solution, the Ni-containing alloy and solid solution each contain Ni and one or more elements selected from the group consisting of Al, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, W, and Co, the V compound contains one or more selected from the group consisting of VN, VCN, and VC, the Al compound contains one or more selected from the group consisting of Al.sub.2O.sub.3, AlN, and AlB.sub.2, a maximum peak position 2 of a 200 plane of the metal phase is less than 51.60, and I.sub.1/(I.sub.1+I.sub.2) is 0.40 to 0.80, where I.sub.1 denotes an X-ray diffraction peak intensity of a 220 plane of the V compound, and I.sub.2 denotes an X-ray diffraction peak intensity of a 200 plane of the metal phase.

A cubic boron nitride sintered material of the present disclosure includes 35 to 100 volume % of a cubic boron nitride grain and 0 to 65 volume % of a binder, wherein: a lattice constant of the cubic boron nitride grain is 3.6140 to 3.6161 , a silicon content in the cubic boron nitride grain is 0.02 mass % or less, and the binder material includes at least one selected from a group consisting of a compound and a solid solution of the compound, the compound consisting of at least one element selected from a group consisting of a group 4 element, a group 5 element, a group 6 element in the periodic table, aluminum, silicon, iron, cobalt and nickel, and at least one element selected from a group consisting of carbon, nitrogen, boron and oxygen.

A cubic boron nitride sintered material includes cubic boron nitride and a binder. The binder includes a first material and a second material. The first material is one or two or more first chemical species each including at least one first metallic element selected from the group consisting of tungsten, cobalt, and aluminum. Each of the first chemical species is a metal, an alloy, an intermetallic compound, a compound, or a solid solution. The second material is one or two or more second chemical species each including at least one second metallic element selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, and chromium. Each of the second chemical species is a solid solution derived from at least one selected from the group consisting of nitride, carbide, and carbonitride. In each of the second chemical species, 0.1 atom % to 10 atom % of aluminum is dissolved.

A superhard structure comprises a body of polycrystalline superhard material comprising a first region and a second region, the second region being adjacent an exposed surface of the superhard structure, the second region comprising a diamond material or cubic boron nitride, the density of the second region being greater than 3.4103 kilograms per cubic metre when the second region comprises diamond material. The material(s) forming the first and second regions have a difference in coefficient of thermal expansion, the first and second regions being arranged such that this difference induces compression in the second region adjacent the exposed surface. The first/a further region has the highest coefficient of thermal expansion of the polycrystalline body and is separated from a peripheral free surface of the body of polycrystalline superhard material by the second region or one or more further regions formed of a material or materials of a lower coefficient of thermal expansion. The regions comprise a plurality of grains of polycrystalline superhard material. There is also disclosed a method of making such a material.

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.

An aluminum-based composite material includes a plurality of coarse crystalline grains (3) of pure aluminum, and a plurality of fine crystalline grains (4) each having an aluminum matrix (1), and a dispersion material (2) dispersed inside the aluminum matrix and formed by reacting a portion or all of an additive with aluminum in the aluminum matrix. The fine crystalline grains exist among the coarse crystalline grains, and the fine crystalline grains have crystalline grain diameters smaller than crystalline grain diameters of the coarse crystalline grains.

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.