Thermodynamic calculation of the T0 curve and metastable phase diagrams of the Ti-M (M = Mo, V, Nb, Cr, Al) binary systems

Based on the experimental data available in the literature, the β-α′/α′′ martensitic transformation and athermal ω formation of the Ti-M (M = Mo, V, Nb, Cr, Al) binary systems at low temperature are thermodynamically described. According to β-α′/α′′ martensitic transformation and metastable ω phase formation temperatures, thermodynamic parameters of these systems are assessed by means of the CALPHAD (CALculation Phase Diagram) approach supported by first-principles calculations. In addition to the metastable ω phase, only solution phases, i.e. liquid, α(hcp), β(bcc) or γ(fcc) are included and their thermodynamic parameters are adopted in the literature or revised in this work. The metastable phase diagrams of the Ti-M (M = Mo, V, Nb, Cr, Al) systems with T0(β/α) and T0(β/ω) curves are calculated using the obtained parameters. Comparisons between the calculated results and experimental data reported in the literature show that almost all the reliable experimental information can be satisfactorily accounted for by the present modeling.