POLYCRYSTALLINE DIAMOND CONSTRUCTION WITH CONTROLLED GRADIENT METAL CONTENT

摘要

Polycrystalline diamond constructions comprises a diamond body attached to a metallic substrate, and having an engineered metal content. The body comprises bonded together diamond crystals with a metal material disposed interstitially between the crystals. A body working surface has metal content of 2 to 8 percent that increases moving away therefrom. A transition region between the body and substrate includes metal rich and metal depleted regions having controlled metal content that provides improved thermal expansion matching/reduced residual stress. A point in the body adjacent the metal rich zone has a metal content that is at least about 3 percent by weight greater than that at a body/substrate interface. The metal depleted zone metal content increases gradually moving from the body, and has a thickness greater than 1.25 mm. Metal depleted zone metal content changes less about 4 percent per millimeter moving along the substrate.