Superhard constructions & methods of making same

A super hard polycrystalline construction 30 comprises a first region 34 comprising a body of thermally stable material comprising a plurality of intergrown grains of super hard material and having an exposed surface 4 forming a working surface and a peripheral side edge 6, a substrate 32 and a region 36 interposed between the first region and the substrate and extending across a surface of the substrate along an interface 37 comprising at least a portion having an uneven topology and comprising a composite material having a first phase comprising a plurality of non-intergrown grains of super hard material and a matrix material, wherein the interposed region has a wear resistance at least three times less than sintered PCD material having the same average grain size of diamond grains as the grains said region. The interposed region preferably comprises a second phase, which may comprise cubic boron nitride or tungsten carbide. The matrix material region may comprise one or more alloys or compounds of one or more transition metals and may also comprise aluminium or nickel or an alloy or compound thereof. A method of forming said construction is also disclosed.