High-temperature phase equilibria in Ti-Al-Mo system

The phase equilibria in a Ti-Al-Mo system have been investigated at 1473 and 1573 K experimentally and theoretically. Phase equilibria were experimentally investigated by in situ x-ray diffraction and thermal analysis as well as by quenching and diffusion couples. From the results, isothermal sections of this system at these two temperatures were constructed and assessed using Thermo-Calc. A part of the ternary phase diagram of Ti-Al-Mo system has revealed the following features: (1) low solution limits of Mo (a few at.% Mo) in both α (disordered hcp structure) and γ (TiAl: the L1₀ structure) phases, (2) the narrow three-phase region of the α+β (bcc Ti terminal solution) +γ phases, and (3) the role of Mo as a strong “β stabilizer.”