Fig. 1: First-principles density functional theory (DFT) calculation of phase stability in A3B1-type (A: (Fe,Co), B: V).

a Stability of candidate ordered precipitates (hP24, L12, and D019) with respect to disordered body-centred cubic (bcc) solid solution at 0 K predicted via DFT calculation. Temperature dependence of Gibbs free energy (G) difference between (b) hP24 and L12, and (c) hP24 and disordered bcc solid solution, approximated by Debye–Grüneisen model. Schematics of configurations are shown in the inset. Connecting lines between symbols are only for visual guidance.