The microstructure and mechanical properties of Ce2O3 reinforced WC-Cu-10Ni-5Mn-3Sn-1.5TiC cemented carbides fabricated via pressureless melt infiltration

Abstract

Microstructure and mechanical properties of WC-Cu-10Ni-5Mn-3Sn-1.5TiC cemented carbides fabricated by pressureless melt infiltration at 1200 °C for 90 min with different Ce2O3 contents (0 wt%, 0.2 wt%, 0.4 wt%, 0.6 wt%, 0.8 wt%, and 1.0 wt%) were investigated. Ce2O3 accelerated the decomposition and dissolution of WC. The melt infiltration reaction products of high carbon solid solution, such as W, Ni2W4C, and (Ti,W)C1-X are precipitated in binder alloys. High carbon solid solution gradually decreased or even disappeared, and W, Ni2W4C, and (Ti,W)C1-X seemed to grow with the increase of Ce2O3 contents. Considering the influence of decomposition and dissolution of WC and the formation of new phases, the size of WC particles decreased while the surface morphology of WC slowly changed from round and blunt to sharp-angle shaped, and the contiguity value of WC particles first decreased and then increased. The changes in microstructural properties of cemented carbides as a function of Ce2O3 inevitably led to the change in mechanical properties. The sample with 0.4 wt% Ce2O3 additions had the highest hardness (94.8 HRA). The highest values of impact toughness and TRS in 0.6 wt% Ce2O3 cemented carbides were 7.15 J cm−2 and 1977.8 MPa, respectively.