The sintering characteristics, microstructure, and mechanical properties of ultrafine WC-12%Co-0.2%VC/0.5%Cr3C2 cemented carbides were investigated. Dilatometric and differential thermal analyses (DTA) indicate that the compacts start to shrink at 600℃, the shrinkage rate peak is at 1190℃, and the liquid formation temperature is lower than the W-C-Co eutectic temperature (1330℃). Microstructure analysis results show that the cemented carbides with free and homogeneous microstructure were obtained when sintered at 1430℃. Continuous and discontinuous grain growth was suppressed due to the synergistic action of VC/Cr3C2. The transverse rupture strength (TRS) of the samples reaches 4286 MPa, with the hardness HRA 92.1. The free and homogeneous microstructure, alloy strengthening, and different phase consti-tutions of binder in the cemented carbides result in high hardness and TRS. Continuous and discontinuous grain growth was observed in the cemented carbide sintered at 1450℃, which results in significant decreases of hardness and TRS. It indicates that VC/Cr3C2 additions in the cemented carbides can only suppress the grain growth at a certain temperature.
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