Influence of Cu-coated diamond addition on the microstructure and mechanical properties of WC-based cemented carbides

Cu-coated diamond enhanced tungsten carbide powder (WC)-Ni cemented carbides were successfully fabricated by spark plasma sintering method. Characterization of the phase composition and microstructure reveal that the diamond particles are well preserved and homogeneously distributed in the composites. Relative density of the samples improved from 92% to 97.6% with 2 wt% Cu-coated diamond addition. Vickers hardness and flexural strength of the samples achieved the maximum value of 2000 HV10 and 950 MPa with 8 and 2 wt% addition, respectively. The fracture toughness improved from 8 to 11 MPa m(1/2) with the added content of diamond increasing from 0 to 4 wt%. The wear rate of the sample is reduced by five times with 6-8 wt% Cu-coated diamond addition. The wear mechanism mainly includes the removal of binder phase, the crushing of WC grains, and the crushing and pulling out of diamond particles.