Development and Application of Methods for Predicting the Temperature-Composition Stability of Refractory-Compounds

摘要

The binary systems between transition metals of the second and third series was considered on the basis of regular solution thermodynamics. This analysis was used to generate seventy-two binary phase diagrams between zirconium, hafnium, niobium, tantalum, molybdenum, tungsten, rhenium, ruthenium, osmium, rhodium, iridium, palladium and platinum. The computed phase diagrams reflect equilibria between the bcc, hcp, fcc and liquid phases. In addition, Laves-type compound phases in the zirconium and hafnium binaries and AuCu3-type phases in zirconium, hafnium, niobium and tantalum binaries were considered. The description permits computation of the entire phase diagram, estimation of heats and free energies of formation of compound phases which occur in these systems and calculation of the vapor pressure and rate of vaporization of elemental components as a function of temperature and composition. (Author)