Stability of the C14 Laves phase (Fe,Si)2Mo from ab initio calculations

The C14 Laves compound Fe2Mo has an outstanding influence in thermodynamic and mechanical properties of steels. Silicon has to be taken into account as it stabilizes the Laves phase to a great extent. Since experimental data are difficult to achieve we have undertaken a calculation approach to the problem of solubility of Si in Fe2Mo. Ab initio data obtained from density functional theory calculations have been used to generate a cluster expansion for the pseudo-binary system Fe2Mo- Si2Mo. Finite temperature thermodynamic properties were obtained via Monte Carlo simulations. Simulations predict the stability of the solid solution (Fe,Si)2Mo, in agreement with experimental results.

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► Solubility of Si in the (Fe,Si)2Mo phase is predicted till a stoichiometry of FeSiMo.
► A first principles study for the pseudo-binary system Fe2Mo–Si2Mo is reported.
► The solid solution shows a miscibility gap which was not experimentally reported.