Microstructure and Properties of Vacuum Sintered Low Co Content WC Hard Materials

Abstract

Low cobalt (Co) WC hard materials were prepared using vacuum sintering. The influences of Co content on the sintering densification behavior, grain growth characteristics, microstructure and mechanical properties of WC hard material were studied. The experimental results show that the addition of a small amount of Co significantly promotes the densification and reduces the sintering temperature. Meantime, the abnormal growth of WC grains was observed. When the sintering temperature is 1 300 °C and the content of Co is less than 1.0wt%, densed WC/Co hard material with fine grains is obtained. When the content of Co is 1wt%, the relative density, Vickers hardness, and flexural strength of WC material are 98.76±0.17%, 24.23±0.41 GPa, and 1 376±67 MPa, respectively. When the Co content is 0.25wt% and 0.5wt%, the optimal sintering temperature of the sample is 1 350 °C. Among them, the relative density, hardness, and flexural strength of WC-0.5wt% Co are 98.79±0.15%, 23.44±0.38 GPa, and 1 233±85 MPa, respectively.

Keywords

low cobalt content WC / sintering densification behavior / grain growth characteristics / mechanical properties

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