Diamond-Hard Alloy Macrocomposite Material: Developmentand Application

Abstract

A new diamond-hard alloy macrocomposite material consisting of diamond grits (0.5-0.8 mm or more in size) and a WC-Co matrix has been developed. The material is characterized by high mechanical properties of the matrix (the same as for WC-Co monolithic hard alloys) while diamonds remain completely intact (no graphitization or dissolution in cobalt melt). This process does not require superhigh pressures. Hard-alloy samples sintered beforehand in conditions that ensure the maximum mechanical properties (1450-1500 °C, 30-60 min holding) are used as initial materials. Hollows (cells) or ditches of specific sizes (depth, width) are made in these samples with mechanical or electrophysical methods, and then diamond crystals (grits) commensurate with the hollows, cells, or ditches are placed in them. Vacuum infiltration (brazing) at moderate temperatures (900-1150 °C) with adhesion-active alloys (or metallized diamonds) is the final stage in the formation of the composite. Therefore, strong adhesion-mechanical fastening of diamond grits in the hard-alloy matrix is ensured. The new material is efficiently used in diamond bits.