| 摘要 |
A polycrystalline diamond construction comprises a diamond body 32 attached to a metallic substrate 40, and having an engineered metal content. The body 32 comprises bonded together diamond crystals with a metal material disposed interstitially between the crystals. A body working surface 34 has metal content of 2 to 8 percent that increases moving away therefrom. A transition region 42, 46 between the body 32 and substrate 40 includes metal rich 42 and metal depleted regions 46 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 46 metal content increases gradually moving from the body, and has a thickness greater than 1.25 mm. Metal depleted zone 46 metal content changes less about 4 percent per millimetre moving along the substrate. A method of forming the construction is also claimed. |
