Thermodynamic Description of the Ti- O System using the Ionic Liquid Model for the Liquid Phase

In this study, the phase diagram and thermodynamic properties of Ti-O system up to 30 mole percent of oxygen was calculated with Calphad method. In this range of oxygen, Ti-O system includes αTi, βTi and liquid phases. αTi and βTi were modeled by “sublattice” model and the model of liquid phase was modeled by “ionic liquid”. Gibbs energy parameters of each phase was optimized by Thermo-Calc software and their phase and thermodynamic diagrams were drawn using this software. The obtained results were compared with experimental and other calculated results. A good accordance was observed between calculated and experimental results. In calculation of phase diagram, with increasing temperature and mole fraction of oxygen, the use of “ionic liquid” model instead of “sublattice” model in thermodynamic description of liquid phase showed better accordance with experimental data.