Comparative Study of the Microstructure and Mechanical Properties of WC/High-Speed Steel Composite Materials Prepared with Co, Ni, and Fe Binders

Three-mm-diameter WC/HSS composites with different binders (Co and Co-Ni-Fe) were prepared. The effect of two different binders on the microstructure and properties of WC powder and HSS composites was compared to investigate the feasibility of substituting Fe and Ni for Co in WC and steel composites. The results show that the WC/HSS sample without binder has significant macropores at the interface, with a porosity of up to 43.76%. The porosity of the composite material containing Co binder is 6.07%. The partial substitution of Ni and Fe for Co significantly reduces the shrinkage temperature of WC powder, and the porosity was reduced to 0.77%. The addition of Ni and Fe in WC facilitates the mutual diffusion among Cr, Mo, and Co elements and the interface bonding between WC and HSS. After adding Ni and Fe elements, the microhardness of the WC/HSS composite materials is slightly lower than that of the Co-added composites, with a microhardness of 1204 HV in the WC region. The HSS microhardness remains almost constant during the binder substitution, maintaining around 600 HV. The wear resistance of the composite outer layer can be effectively enhanced by the use of Co, Ni, and Fe additives.