Effect of Fe/Ni ratio on the microstructure and properties of WC-Fe-Ni-Co cemented carbides

摘要

WC-Fe-Ni-Co cemented carbides with a constant Co content were successfully prepared through low pressure sintering, and the effects of Fe/Ni ratio on the microstructure and properties of the cemented carbides were studied in detail. The X-ray diffractometer and transmission electron microscopy results show that the Fe/Ni ratio is a critical factor that affects the structure of the Fe-Ni-Co binder in the alloys, as it gradually changes from fcc gamma-(Fe,Ni) to bcc alpha-(Fe,Ni) with an increase in the Fe/Ni ratio. Furthermore, the WC grains have a finer and more rounded shape and are more uniformly distributed in the matrix as the Fe/Ni ratio increases. Additionally, both the magnetic saturation (CoM) and coercive force (Hc) increase as the Fe/Ni ratio increases. The relative density of all alloys is greater than 99.93% except for the alloy with the Fe/Ni ratio of 1.67 (99.01%). Ignoring the effect of the lower relative density (Fe/Ni = 1.67), increasing the Fe/Ni ratio can enhance the hardness, transverse rupture strength and wear resistance of the alloys but can reduce the fracture toughness and corrosion resistance at the same time.