  A theoretical model for understanding the formation of interfacial thin films
is presented, which combines density functional theory calculations for
interface energies with thermodynamic modeling techniques for multicomponent
bulk systems. The theory is applied to thin film formation in VC-doped WC-Co
cemented carbides. It is predicted that ultrathin VC films may exist in WC/Co
interfaces at the high temperature sintering conditions where most of the WC
grain growth occurs, which provides an explanation of the grain growth
inhibiting effect of VC additions in the WC-Co system.
