Methods of forming polycrystalline diamond cutters

Abstract

A method for forming a cutting element that includes forming at least one cavity in at least one surface of a polycrystalline abrasive body; placing the polycrystalline abrasive body adjacent a substrate such that an opening of at least one cavity is adjacent the substrate at an interface, wherein an interface surface of the substrate is non-mating with the polycrystalline abrasive body; and subjecting the polycrystalline abrasive body and substrate to high pressure / high temperature conditions is disclosed.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority, under 35 U.S.C. §119, to U.S. Patent Application No. 61 / 081,619, filed on Jul. 17, 2008, which is herein incorporated by reference in its entirety.BACKGROUND OF INVENTION[0002]1. Field of the Invention[0003]The invention relates generally to polycrystalline diamond composites and cutting structures. More particularly, this invention relates to polycrystalline diamond cutting structures that having non-planar interfaces and method of forming such non-planar interfaces.[0004]2. Background Art[0005]Polycrystalline diamond compact (“PDC”) cutters have been used in industrial applications including rock drilling and metal machining for many years. In a typical application, a compact of polycrystalline diamond (PCD) (or other superhard material) is bonded to a substrate material, which is typically a sintered metal-carbide to form a cutting structure. PCD comprises a polycrystalline mass of diamonds (typically ...

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Benefits of technology

[0019]Other aspects and advantages of the invention will be apparent from the following description and the appended claims.

Problems solved by technology

Common problems that plague cutting elements and specifically cutters having an ultra hard diamond-like cutting table such as PCD, polycrystalline cubic boron nitride (PCBN), or thermally stable polycrystalline diamond (TSP) bonded on a cemented carbide substrate are chipping, spalling, partial fracturing, cracking or exfoliation of the cutting table.

These problems result in the early failure of the cutting table and thus, in a shorter operating life for the cutter.

It has been thought that these problems, i.e., chipping, spalling, partial fracturing, cracking, and exfoliation of the diamond layer may be caused in part by the difference in the coefficient of thermal expansion between the diamond and the substrate.

Specifically, the problems are thought to be caused by the abrupt shift in the coefficient of thermal expansion on the interface between the substrate and the diamond.

This abrupt shift causes the build-up of residual stresses on the cutting layer.

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