Abstract: This disclosure relates to a tool assembly for friction stir welding. The tool assembly comprises a tool holder and a puck each having an axis of rotation. The tool holder comprises a tool post and the puck comprises a pin. The puck is coupled to the tool post. The tool assembly is adapted such that during friction stir welding, run-out of the tool holder, measured as the run-out between the axis of rotation of the tool holder and the axis of rotation of the pin, does not exceed 10 ?m.

Abstract: A super hard construction comprises a substrate comprising a peripheral surface, an interface surface and a longitudinal axis extending in a plane and a super hard material layer formed over the substrate and having an exposed outer surface, a peripheral surface extending therefrom and an interface surface. One of the interface surface of the substrate or the interface surface of the super hard material layer comprises one or more projections arranged to project from the interface surface, the one or more projections being spaced from the peripheral surface of the substrate and a peripheral flange extending between the peripheral side edge and the interface surface. The peripheral flange is inclined at an angle of between around 5 degrees to around 30 degrees to a plane substantially perpendicular to the plane through which the longitudinal axis extends.

Abstract: A super hard construction comprises a substrate and a super hard material layer formed over the substrate. One of the interface surface of the substrate or the interface surface of the super hard material layer comprises a plurality of spaced-apart projections arranged to project from the interface surface; the projections being arranged in a substantially annular discontinuous first array around the central longitudinal axis and spaced from the peripheral surface of the substrate by a distance of between around 1 mm to around 1.5 mm. A second substantially annular discontinuous array of projections is positioned radially within the first array. The projections in the second array are positioned to radially align with spaces between the projections in the first array, the interface surface between the projections being substantially planar; and the projections in the first array are of a greater height than the projections in the second array.

Abstract: A super hard construction comprises a substrate comprising a peripheral surface, an interface surface and a longitudinal axis extending in a plane and a super hard material layer formed over the substrate and having an exposed outer surface, a peripheral surface extending therefrom and an interface surface. One of the interface surface of the substrate or the interface surface of the super hard material layer comprises one or more projections arranged to project from the interface surface, the one or more projections being spaced from the peripheral surface of the substrate and a peripheral flange extending between the peripheral side edge and the interface surface. The peripheral flange is inclined at an angle of between around 5 degrees to around 30 degrees to a plane substantially perpendicular to the plane through which the longitudinal axis extends.

Abstract: 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 3.4×103 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.

Abstract: A super hard construction (1) comprises a substrate (30) and a super hard material layer (32) formed over the substrate. One of the interface surface (38) of the substrate or the interface surface of the super hard material layer comprises a plurality of spaced-apart projections (44, 46); the projections (44) being arranged in an annular discontinuous first array around the central longitudinal axis and spaced from the peripheral surface (40) of the substrate by a distance of between around 1 mm to around 1.5 mm A second annular discontinuous array of projections (46) is positioned radially within the first array. The projections in the second array are positioned to radially align with spaces between the projections in the first array, the interface surface between the projections being substantially planar; and the projections in the first array are of a greater height than the projections in the second array.

Abstract: A superhard structure comprises a body of polycrystalline superhard material comprising a first region and a second region. The second region is adjacent an exposed surface of the superhard structure and comprises a diamond material or cubic boron nitride with a density greater than 3.4×103 kilograms per cubic meter 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 in part from a peripheral free surface of the body by the second region or one or more further regions formed of a material(s) of a lower coefficient of thermal expansion. The regions comprise a plurality of grains of polycrystalline superhard material.

Abstract: A tip for a degradation tool, the tip comprising a PCD structure (20) joined to a cemented carbide substrate (30); the PCD structure comprising a plurality of strata (24, 25) arranged so that adjacent strata have alternating compressive and tensile stress states, adjacent strata comprising different PCD grades and being directly bonded to each other by inter-growth of diamond grains; each stratum having a mean thickness of at most 500 microns; the PCD structure defining a working end including a rounded conical apex (22) having a radius of curvature of 1.3 mm to 4 mm.

Abstract: A pick tool for degrading asphalt or rock, comprising a PCD element; the PCD element comprising a PCD structure (20) bonded to a cemented carbide support body (30) at an interface; the PCD structure comprising a first region (24) and a second region (25) adjacent the first region, the second region bonded to the first region by intergrowth of diamond grains; the first region (24) comprising a plurality of alternating strata (24c, 24t), each stratum having a thickness in the range of about 30 to 300 microns; the second region comprising a plurality of strata (25a, 25b), one or more strata in the second region (25a) having a thickness greater than the thicknesses of the individual strata in the first region (24c, 24t), wherein the alternating strata in the first region (24) comprise first strata alternating with second strata, the first strata being in a state of residual compressive stress and the second strata being in a state of residual tensile stress.

Abstract: A tip for a degradation tool, the tip comprising a PCD structure (20) joined to a cemented carbide substrate (30); the PCD structure comprising a plurality of strata (24, 25) arranged so that adjacent strata have alternating compressive and tensile stress states, adjacent strata comprising different PCD grades and being directly bonded to each other by inter-growth of diamond grains; each stratum having a mean thickness of at most 500 microns; the PCD structure defining a working end including a rounded conical apex (22) having a radius of curvature of 1.3 mm to 4 mm.

Abstract: A pick tool for degrading asphalt or rock, comprising a PCD element; the PCD element comprising a PCD structure (20) bonded to a cemented carbide support body (30) at an interface; the PCD structure comprising a first region (24) and a second region (25) adjacent the first region, the second region bonded to the first region by intergrowth of diamond grains; the first region (24) comprising a plurality of alternating strata (24c, 24t), each stratum having a thickness in the range of about 30 to 300 microns; the second region comprising a plurality of strata (25a, 25b), one or more strata in the second region (25a) having a thickness greater than the thicknesses of the individual strata in the first region (24c, 24t), wherein the alternating strata in the first region (24) comprise first strata alternating with second strata, the first strata being in a state of residual compressive stress and the second strata being in a state of residual tensile stress.

Abstract: 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 3.4×103 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 fir 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.

Abstract: A superhard structure comprises a body of polycrystalline superhard material comprising a first region and a second region. The second region is adjacent an exposed surface of the superhard structure and comprises a diamond material or cubic boron nitride with a density greater than 3.4×103 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 in part from a peripheral free surface of the body by the second region or one or more further regions formed of a material(s) of a lower coefficient of thermal expansion. The regions comprise a plurality of grains of polycrystalline superhard material.