Electron backscattered diffraction was used to determine the orientation of WC crystals in a WC-Co composite and atomic force microscopy was used to measure the shapes of planar sections of the same crystals. A stereological analysis was used to determine that {10▪0} prism facets and the {00▪1} basal planes were the WC surfaces that were most frequently in contact with Co. Further, the WC habit was an approximately equiaxed trigonal prism bound by 3 prism facets and 2 basal facets. An analysis of some 15600 grain boundaries showed that certain interfaces occurred with a frequency that was much higher than would be expected in a random distribution and that the grain boundary habit planes also had {10▪0} and {00▪1} orientations. Eleven percent of all the observed WC-WC interfaces were 90° twist boundaries about [10▪0]. Two types of boundaries with a 30° rotation about [00▪1], a twist and an asymmetric tilt, comprise 3% of the population.

Geometric and Crystallographic Characterization of WC Surfaces and Grain Boundaries in WC-Co Composites. C.S.Kim, G.S.Rohrer: Interface Science, 2004, 12[1], 19-27