Experimental Investigation and Thermodynamic Assessment of Phase Equilibria in the Hf-Ti-V Ternary System

In this study, two isothermal sections of the Hf-Ti-V ternary system at 1100 and 1300 °C were experimentally investigated by means of back-scattered electron, electron probe microanalysis and x-ray diffraction. The isothermal section at 1100 °C consists of one three-phase region and three two-phase regions, without any ternary compounds. The β(Hf, Ti) phase forms a large continuous solid solution at 1300 °C, even extends to Hf-V side. The solubility of V in β(Hf, Ti) phase is large, while the solubility of V in the α(Hf, Ti) phase is small. A thermodynamic description of the Hf-Ti-V system was carried out based on the experimental data determined in this work. The calculated phase diagrams are in good agreement with the present experimental results.