The effects of micron WC contents on the microstructure and mechanical properties of ultrafine WC–(micron WC–Co) cemented carbides

• The ultrafine WC–(micron WC–Co) cemented carbides were fabricated.
• The addition of micron-sized WC particles can generate the deflection of crack in the extension process.
• The addition of micron-sized WC particles can improve the fracture toughness obviously.

In this work, the effects of micron grained WC additions on the microstructure and properties of ultrafine WC–(micron WC–Co) cemented carbides produced through low pressure sintering processes were investigated by scanning electron microscope and mechanical properties tests. The results show that the obvious crack deflection and transgranular fracture phenomenon could be observed with the addition of micron WC, which can resist the crack propagation and improve the toughness of cemented carbides. The sintered ultrafine WC–(micron WC–Co) hardmetals demonstrate excellent hardness and fracture toughness values (HV30: 1700 kg/mm2, KIC: 13.82 MPa m1/2). These inhomogeneous ultrafine WC–(micron WC–Co) cemented carbides have considerable potential for use in structural applications.