A thermodynamic database for both Ti-based alloys and TiAl-based materialsFriday (10.11.2017) 11:35 - 11:55 Part of:
A new titanium database was developed within a 23-element framework. It is the first thermodynamic database which covers both Ti-based alloys and TiAl-based materials, and, moreover, it can be employed to design light alloys based on the Al3Ti and AlTi3 intermetallic phases. The database is developed in a systematic way in order to cope with the complexity in the phase relations and phase transformations in titanium alloy systems. For instance, the phase transformations among variant ω phases, including the simple solid solution based on ωTi, and the ordered compounds of the C32 type, the B82 type, the D88 type and the Ti5Ga4 type, have been examined carefully from a crystallographic viewpoint, so that reasonable thermodynamic models could be adopted for them. High throughput density function theory (DFT) calculations are employed to compute thermodynamic quantities for intermetallic compounds and solid solutions (including those based on intermetallics). Regarding the calculations for the A2, A3 and ω solutions, special quasirandom structures (SQSs), small sets of ordered structures (SSOSs) and supercells have been used to approximate the random substitutional solution phases in both binary and ternary systems.