Ultrafine WC-Co cemented carbide with enhanced mechanical properties prepared by oscillating sinter forging

Abstract

A novel oscillating sinter forging (OSF) was used to prepare ultrafine WC-Co cemented carbides for the first time. The mechanical properties of the resultant samples were characterized and compared with those of cemented carbides prepared by conventional sinter-forging (CSF). The results show that the samples prepared by OSF have higher hardness and fracture toughness. The sample prepared by OSF at 1125 °C has a hardness of 1911 kg/mm2 and fracture toughness of 17.52 MPa·m1/2. These values are much higher than those obtained from the sample prepared by CSF and outperform the general trade-off between hardness and toughness observed in cemented carbides processed by other processes. Microstructural analysis suggests that OSF samples exhibited much better microstructure, such as higher relative density, finer grains, more uniform microstructure, more fcc-structured Co phase, and more ∑2 low-energy grain boundaries. The effects of microstructure on the mechanical properties were discussed. The current study suggests that OSF has excellent synergistic hardening and toughening effects and is a promising technique for preparing high-performance cemented carbides.