Manufacturing and properties of polycrystalline WC-Co based cemented carbides

Polycrystalline WC-Co hardmetals consist of coarse polycrystalline WC-particles, which itself consist of many nanoscaled WC crystals. Due to higher hardness of nanoscaled polycstalline WC (up to 2900 HV10) compared to conventional medium or coarse grained WC (~ 1500 HV10) these novel hardmetals offer a much better hardness while keeping the same fracture toughness of conventional monocrystalline hardness with the same Co content and WC particle size. By adjusting the Co content as well as the particle size and shape of the polycrystalline WC particles the properties can be controlled over a larger hardness range. For instance, with 10 wt-% Co and a carbide particle size in the starting powder from 10 µm to 20 µm a hardness of 1830 HV10 and a fracture toughness of 9.3 MPa*m1/2 was achieved.