Constitution of liquid iron-silicon alloys

Conclusions

• 1. The x-ray diffraction patterns for alloys of the iron-silicon system depend largely on the particular alloy composition.

• 2. A random distribution of atoms does not occur in any of the alloys examined here.

• 3. The highest-level order is revealed in. FeSi and Fe₃Si. For these alloys the calculated J(Θ) and D(r) relations will agree most closely with the respective experimental curves, if the calculations are based on models with distances between iron and silicon atoms somewhat shorter than in a crystal.

• 4. The results of this study support the hypothesis that the lowest-silicon compound in the liquid state is characterized by the presence of ordered regions the atomic structure of which corresponds to a distorted Fe₃Si lattice. The basic differences between them are reflected in the Fe-Si distances, which are somewhat shorter in the melt than in the crystal at the melting temperature, while some of the Fe-Fe bonds, to the contrary, become notably longer.

The distribution of atoms in molten iron monosilicide is probably close to that in a crystal and differs from it only by some shorter Fe-Si distances and a less ordered mutual orientation of Fe-Si pairs.

Liquid iron disilicide has, apparently, a microheterogeneous quasieutectic structure the components of which are clusters of silicon atoms and complexes similar in composition to iron monosilicide but with a lower coordination number.