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Herein, the pressure dependence of the structural, mechanical, and electronic properties is investigated for Fe2Si, FeSi, Fe3Si, α‐FeSi2, β‐FeSi2, Fe5Si3, and Fe11Si5 in the pressure range of 0–100 GPa based on density functional theory. The calculated lattice constants are in good agreement with the experimental results. The order of the thermodynamic stability of the seven structures is FeSi > Fe5Si3 > Fe2Si > β‐FeSi2 > Fe11Si5 > α‐FeSi2 > Fe3Si. The electronic properties are analyzed including density of states and band structures. The mechanical properties of FeSi, Fe2Si, Fe5Si3, α‐FeSi2, and β‐FeSi2 are studied thoroughly: The elastic constants are obtained under different pressures; the mechanical stability under the considered pressures is evaluated by the stability criteria. The results show that FeSi, Fe5Si3, and β‐FeSi2 are mechanically stable at pressures from 0 to 100 GPa; Fe2Si is unstable under compression; and α‐FeSi2 is unstable in the range of 60–100 GPa. The values of B, G, and E are calculated, which indicate that the ability to resist deformation of the material increases with the increase in pressure. The B/G values are calculated, suggesting that both Fe5Si3 and Fe2Si are ductile materials; the brittle–tough transition is observed in FeSi, α‐FeSi2, and β‐FeSi2.

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The influences of different ratios of Fe and N on the structure, mechanical and electronic properties of Fe[Formula: see text]N[Formula: see text] compounds were studied by using the first-principles study. Our obtained lattice parameters are in excellent agreement with the experimental data. The calculated density of the Fe[Formula: see text]N1 compounds increases with the Fe content, which is almost consistent with the trend of the experimental results. The elastic constants indicate that the Fe[Formula: see text]N[Formula: see text] compounds are mechanically stable. The values of [Formula: see text]/[Formula: see text] and Poisson’s ratio indicate that the Fe[Formula: see text]N[Formula: see text] compounds exhibit ductile manner. As Fe content increases, [Formula: see text]/[Formula: see text] and Poisson’s ratios decrease monotonically. In particular, Fe4N1 has the highest hardness among all the considered Fe[Formula: see text]N[Formula: see text] compounds. The obtained density of states shows that Fe[Formula: see text]N[Formula: see text] is metallic in nature. The peak of the state density becomes sharper with the increase of N content, indicating that the localization of these alloys is enhanced. Among the Fe[Formula: see text]N[Formula: see text] compounds, Fe1N1 has been found to be the most stable with respect to the band filling theory calculation.