Thermodynamic Assessments of Ti-Al, Ti-Fe, and Ti-Al-Fe Systems with Four-Sublattice Description of Ordered Body-Centered Cubic Phase and Density Functional Theory Data
Zhi Liang, Ursula R. Kattner, Kamal Choudharry, Francesca Tavazza, Carelyn E. Campbell
Abstract
Abstract A thermodynamic description of the Ti-Al-Fe system was established with reassessed Ti-Al and Ti-Fe binary systems using density function theory (DFT) data. All stable and metastable end members of BCC_B2, BCC_D0 3 /B32, BCC_L2 1 , inverse BCC_L2 1 , Laves C14, D0 19 -Ti 3 Al, L1 0 -TiAl, Ti Al 2 , Ti 3 Al 5 , D0 22 -TiAl 3 , τ 2 and τ 3 in the Ti-Al, Ti-Fe and Ti-Al-Fe systems were energetically defined with available experimental data and DFT calculations, reaching reasonable consistency. The ternary description was used to successfully calculate the A2-B2-L2 1 transformation in Fe-rich corner and A2-B2 transformation in Ti-rich corner, allowing the design of Ti-rich and Fe-rich alloys in this system.