Inelastic deformation of (Ti, V)C alloys - Part 1 Hot-pressing kinetics

The densification behaviour of (Ti, V) C alloys was studied in order to prepare fully dense, single phase alloys. The hot-pressing experiments were conducted on two compositions, TiC and TiC-75% VC, at temperatures between 1300 and 1900° C and pressure up to 120 M Pa. The effects of temperature and composition on final porosity, grain size and phases present were determined. The diffusion coefficients determined from densification data agree well with the grain-boundary diffusion coefficient of carbon. This observation, combined with microstructural evidence, indicates that the final stage of densification is controlled by grain-boundary diffusion of carbon and/or metal. The enhanced densification and grain growth in VC rich samples are attributed to the presence of second phase material along the grain boundaries. The rapid interdiffusion of titanium and vanadium in (Ti, V) C to form a single phase, raises the possibility of faster diffusion along the migrating boundaries in contrast to the stationary boundaries.