Tungsten carbides and W-C phase diagram

The crystal structures of the tungsten monocarbide delta-WC and the disordered lower carbide delta-WC are studied. Using magnetic susceptibility measurements, the hexagonal carbide delta-WC is shown to be stable front 300 to 1200 K. The sequence of phase transformations associated with beta-W2C ordering is analyzed. The teniperature and composition stability hinits of the cubic carbide gamma-WC1-x are evaluated, and the first data are presented oil the variation of its lattice parameter with composition. An optimized W-C phase diagram is proposed which takes into account detailed structural Lind phase-equilibrium data for tungsten carbides.