Segregation of vanadium at the WC/Co interface in VC-doped WC-Co

Morphology of carbide grain in WC-12 wt.% Co-0.5 wt.% VC was examined by HREM and EDS with a special interest in the segregation of V at the WC/Co interfaces. A small addition of VC in WC-Co is effective to suppress the grain growth of carbide grains. HREM observation revealed that the WC/Co interfaces are faceted and consist of mainly two kinds of habit planes, (10 (1) over bar 0) and (0001), respectively. EDS analyses clearly showed the segregation of doped V along the interfaces. In addition, the concentration of segregated V is higher at the (0001) type habit plane than (10 (1) over bar 0) one. The retardation of the grain growth of carbide grains in the VC-doped WC-Co is closely related to the formation of the faceted WC/Co interface.