A Study Of WC-Co Cemented Carbide Modified By Nanosized Rare Earth

For the purpose of cemented carbide applications, the nanosized rare earth additives were added to modify the micron-sized WC-Co cemented carbide. By using the following experimental techniques, including scanning electron microscope (SEM), energy dispersive spectrometer(EDS), Vickers hardness, transverse rupture strength, fracture toughness, impact toughness, impact abrasive wear, the microstructure, mechanical properties and their influencing factors were studied and discussed. The better fabricating proposal was determined.In this paper, nanosized RE/TiC additives and nanosized RE additives were determined according to the material design. The hard metal with high density up to 99.7% was fabricated successfully by adjusting technical parameters and component proportioning.From the result of coercive force and the microstructure it can be seen that the grain size was reduced obviously when nanosized rare earth additives were added, and the mechanism is the grain refining strengthening.The energy dispersive spectrometer result indicated that the nanosized rare earth additives distributed more uniformly when the sintering temperature was 1450℃and the milling time was 36h .Conventional mechanical test indicated that when nanosized RE additives was added to the hard metal, the vicker hardness, transverse rupture strength, fracture toughness, impact toughness all improved, and for example the transverse rupture strength, fracture toughness, impact toughness of which the content is 0.1% were improved 17.5%,11.5% and 31.5% respectively.The fracture surface shows that the fracture mechanism was transcrytalline fracture and intergranular fracture , and the bonding strength between the grains was better when the nanosized rare earth additives were added.The impact abrasive wear results show that the wear resistance was improved obviously by adding nanosized RE/TiC and RE additives, and the better were improved more than 100%.