Abstract: Cutting elements of this invention include an ultra hard body joined with a metallic substrate. The body includes an uppermost layer comprising a plurality of bonded ultra hard crystals and interstitial regions, and that defines a body working surface. The uppermost layer includes an outer region that is relatively more thermally stable than a remaining portion of the uppermost layer. The body further includes an intermediate layer joined to the uppermost layer, comprising a plurality of bonded ultra hard crystals, and having a wear resistance less than that of the uppermost layer remaining region. The body may additionally include a lowermost PCD layer that is interposed between and attached to the intermediate layer and the substrate.

Abstract: Thermally-stable polycrystalline diamond materials of this invention comprise a first phase including a plurality of bonded together diamond crystals, and a second phase including a reaction product formed between a binder/catalyst material and a material reactive with the binder/catalyst material. The reaction product is disposed within interstitial regions of the polycrystalline diamond material that exists between the bonded diamond crystals. The first and second phases are formed during a single high pressure/high temperature process condition. The reaction product has a coefficient of thermal expansion that is relatively closer to that of the bonded together diamond crystals than that of the binder/catalyst material, thereby providing an improved degree of thermal stability to the polycrystalline diamond material.