Effect of Mo2C on the microstructure and properties of (W, Mo)C-10Co cemented carbides

Mo 2 C doped WC-10Co alloys were prepared via an in - situ synthesis method composed of steps of spray drying, roasting, carbothermal pre-reduction and carbonization-vacuum sintering. The effects of Mo 2 C content on the microstructure and mechanical properties of cemented carbides were studied in detail. The results showed that WC and Mo 2 C formed a complete solid solution by the current method. With the increase of Mo 2 C content from 0 wt% to 0.5 wt%, the effects of solution strengthening and fine grain strengthening were obvious, and the grain size was decreased from 0.72 ± 0.32 μm to 0.62 ± 0.27 μm, while the hardness was improved from 1316 ± 20 HV 30 to 1549 ± 14 HV 30 . However, the (W, Mo)C solid solution would deteriorate the fracture toughness of the alloys. With the further increase of Mo 2 C content to 9 wt%, the lattice distortion in the solid solution became more serious. Meanwhile, the dissolution of more Mo 2 C in the liquid Co further weakened the dissolution-precipitation process of the solid solution, thus inhibiting the growth of grains and increasing the hardness of the alloys. In addition, with the increase of Mo 2 C content, the dominant fracture mode of the alloy changed from transgranular fracture to intergranular fracture .