Low-Energy Grain Boundaries in WC-Co Cemented Carbides

Abstract

The influencing factors, distribution rules and formation mechanisms of the typical low-energy grain boundaries in the WC-Co cemented carbides were studied. A number of characterizations were performed on the grain morphology and the features of low-energy grain boundaries in the cemented carbides, and the correlations of the grain shape aspect ratio, WC contiguity and distribution of the low-energy grain boundaries were analyzed. It was found that the ∑2 grain boundaries have a high fraction in the cemented carbide with stable complexions which lead to fine grain size and high WC contiguity. The ∑13a grain boundaries are likely to form in the cemented carbide with anisotropic surface energy by coalescence of WC platelets with a large shape aspect ratio. The present results suggest that the low-energy grain boundaries in the cemented carbides can be tailored by matching the grain growth inhibitor and the sintering temperature of the initial WC-Co composite powder.