Abstract: A polycrystalline super hard construction comprises a body of polycrystalline super hard material and a substrate bonded to the body along an interface. The substrate a first end surface forming the interface, the first end surface comprising a projection extending from the body of the substrate into the body of super hard material towards the cutting face, the body of polycrystalline material extending around the projection. The body of polycrystalline material comprises a first region more thermally stable than a second region, the first region comprising an annular portion located around the projection, the second region extending between and bonding the first region to the substrate. The first region has a thickness from the cutting face along the peripheral side edge to the interface of at least around 3 mm and a portion of the projection has a thickness measured in a plane extending along the longitudinal axis of at least around 3 mm.

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.