Effect of CeO2 and VC co-doping on the microstructure and properties of WC-10Co cemented carbide

Abstract

Combining spray drying and in-situ synthesized technology, WC-10Co cemented carbides with uniform composition was prepared by vacuum sintering to investigate the effects of different CeO2 contents (0 wt%, 0.5 wt%, 1 wt%, 2 wt%, 4 wt%) as well as co-doping with CeO2 and VC on the microstructure and mechanical properties. With increasing CeO2 addition from 0 wt% to 0.5 wt%, the WC grain size decreased from 0.79 ± 0.35 μm to 0.62 ± 0.24 μm. The hardness, fracture toughness and transverse rupture strength (TRS) of the alloy with 0.5 wt% CeO2 all reached the maximum values of 1752 ± 28 HV30, 18.50 ± 0.35 MPa·m1/2 and 2245 ± 35 MPa, respectively, which indicated that the mechanical properties of cemented carbide could be simultaneously improved by adding 0.5 wt% CeO2 to refine the WC grains. However, as the CeO2 content increased to 4 wt%, the hardness gradually decreased, while the fracture and TRS all slightly decreased first and then tended to be stable. Moreover, the corrosion resistance of alloys first increased and then decreased with the increase of CeO2 content. The 0.5 wt% CeO2 alloy had the best corrosion resistance. After adding 0.5 wt% VC, the grain size of alloys became smaller and distribution of Co binder was more uniform. Compared to the samples with only added CeO2, the alloy with co-addition of 0.5 wt% CeO2 and 0.5 wt% VC exhibited the best comprehensive mechanical properties. The hardness, fracture toughness and TRS of the alloy with co-addition of 0.5 wt% CeO2 and 0.5 wt% VC were 1987 ± 44 HV30, 16.10 ± 0.34 MPa·m1/2 and 2023 ± 78 MPa, respectively.