Sintering Behavior and Mechanical Properties of Cr3C2 Doped Ultra-Fine WC-Co Cemented Carbides: Experment Guided with Thermodynamic Calculations

The influence of Cr3C2 doping on the sintering process and mechanical properties of WC-Co cemented carbides was studied. Using differential thermal analysis of green powders and thermodynamic calculations, the disappearing temperature of solid-state binder phase in the ultra-fine WC-Co cemented carbides with different amounts of Cr3C2 dopant was first investigated and then verified to descend with the increase of Cr content. Based on these investigations, the sintering temperatures of three alloys with 0.3, 0.5 and 0.65 wt% Cr were selected to high by 50 degrees C than the phase disappearing temperature of solid-state binder. Compared with the commercial sample with the sintering temperature at 1410 degrees C for Cr3C2 doped WC-Co cemented carbides, the optimized sintering temperatures lead to finer microstructures and better mechanical properties, such as transverse rupture strength and hardness. In addition, the reliability for the performance of WC-Co cemented carbides prepared with the optimized sintering schedule is significantly improved in comparison with the commercial sample. The strategy from the present work can be used to design sintering process parameters during the manufacture of ultrafine WC-Co cemented carbides.