Effect of rapid cooling on microstructure and properties of nanocrystalline WC-9%co-Cr3C2-VC cemented carbide

Nanocrystalline cemented carbide is expected to become an ideal material for high-performance alloy tools due to its high strength, hardness, toughness, and wear resistance. In this work, nanocrystalline cemented carbides prepared at different sintering temperatures through different cooling methods were investigated with Cr3C2 and VC as grain growth inhibitors. The effects of sintering temperature and cooling process on the microstructure and mechanical properties were systematically studied. It was found that low-pressure sintering and rapid cooling process can significantly optimize the structure and improve the mechanical performance. The nanocrystalline cemented carbide shows excellent comprehensive properties, i.e. transverse rupture strength (TRS) of 5280 MPa and hardness of 1987 kg.mm(-2) (94.0HRA) at high level compared with the reported values. The mechanisms of strengthening and toughening of nanocrystalline cemented carbide were contributed to the WC grains tip rounding and low-misfit Co(111)||(W,V,Cr)Cx||WC(1010) interface at rapid cooling process, and a new method for improving cemented carbide by interface strengthening was proposed.