Thermodynamic modeling of the Fe–Ti–V system

The thermodynamic optimization of the Fe–Ti–V system was carried out using the CALPHAD technique. The solution phases (liquid, bcc, fcc and hcp) were modeled as substitutional solution. The compound Fe2Ti with C14 structure had a solubility of 34 at% V at 1273 K and was described as (Fe,Ti,V)2(Fe,Ti,V) by a two-sublattice model in the Fe–Ti–V system. The compound FeTi with B2 crystal structure had a solubility of 9 at% V at 1273 K and was treated as (Fe,Ti,V)0.5(Fe,Ti,V)0.5(Va)3 in order to cope with the order–disorder transition between FeTi(B2) and bcc solid solution (bcc-A2). The sigma phase was treated as the formula (Fe,Ti,V)10(Fe,Ti,V)20 in the Fe–Ti–V system. A set of self-consistent thermodynamic parameters of the Fe–Ti–V system was obtained.

Research highlights
► The Fe–Ti–V system was re-optimized using the CALPHAD technique.
► The order–disorder transition model was used between FeTi(B2) and bcc(A2).
► A set of self-consistent thermodynamic parameters was obtained.