Fabrication and mechanical properties of WC-10Co cemented carbides with plate-like WC grains

Abstract

WC-10Co cemented carbides with plate-like WC grains were fabricated using ultrafine WC as seeds via the reaction among tungsten, cobalt and carbon. The effects of ultrafine WC contents on the microstructural characteristics and mechanical properties were investigated. Because the density of W is higher than that of complex carbide particles (CoxWyCz), some cracks could be existed in the thin flake W particles owing to the volume expansion, bringing about the formation of flake WC nuclei. Some flake WC nuclei aggregates could be seen in the alloys without the addition of ultrafine WC. The addition of ultrafine WC could bring about the gradually disappearance of flake WC nuclei aggregates and accelerate the formation of plate-like WC grains. The high content of plate-like WC could bring about high hardness. Furthermore, the palte-like WC grains could efficiently hinder the propagation of the cracks as the crack path deflection and crack bridging, and inevitably improve the transverse rupture strength.