With the continuous increase in the manufacturing cost of conventional WC-Co cemented carbides, the development of low-cost, high-performance cobalt-free or low-cobalt cemented carbides has become a research hotspot in the industry. In this study, cobalt-free WC-Ni-Fe-Mo cemented carbides were successfully prepared by low-pressure sintering using fine WC powder as the raw material and Ni-Fe-Mo as the composite binder phase. The effect of Mo content variation on the microstructure, mechanical properties, and friction and wear properties of the alloys was systematically investigated. The results show that the as-prepared alloys consist of a two-phase structure composed of WC phase and γ-(Fe, Ni) phase. The addition of Mo further leads to the formation of Mo2C and Ni3W3C phases. With increasing Mo content, the average WC grain size gradually decreases from 0.45 μm to 0.31 μm, and the grain size distribution becomes more uniform. Meanwhile, the alloy density gradually decreases, hardness gradually increases, fracture toughness decreases, and transverse rupture strength first increases and then decreases. Affected by the brittle Ni3W3C phase, the wear resistance of the alloys gradually deteriorates. When the Mo content is 0.25 wt%, the alloy exhibits the best comprehensive performance, with a transverse rupture strength of 4078 MPa, a hardness of 90.5 HRA, a fracture toughness of 12.11 MPa·m1/2, and a friction coefficient of 0.42. This indicates that an appropriate addition of molybdenum has a significant strengthening effect on the mechanical properties of the material, thereby laying an experimental foundation and providing process guidance for the development of novel low-cost, high-performance cobalt-free cemented carbides.
Zhang et al. (Sun,) studied this question.