Co-phase penetration of WC(10(1)over-bar-0)/WC(10(1)over-bar-0) grain boundaries from first principles -: art. no. 115415

We examine different interface energy relationships at the WC(10 (1) over bar0) surface in the WC-Co cemented carbide using density-functional theory. To assess the stability of WC/WC grain boundaries, 90degrees-twist grain boundaries and a 27degrees-twist grain boundary are considered. In addition, we investigate the adhesion properties at the Co(001)/WC(10 (1) over bar0) interface by analyzing twelve different interfacial structures, including both W and C terminations of the carbide. The results indicate that the adhesion properties of Co on WC(10 (1) over bar0) can be explained either by a considerable adjustment of the interfacial Co atoms to their interfacial equilibrium positions, or by an interfacial structure where the WC surface has a mixed composition of C and W atoms. Finally, the WC/WC grain boundary and Co/WC interface energy relationships are discussed in the context of liquid-phase sintering.