Study of solid state reactions during mechanical alloying of Si–Fe system with first-principles calculation

• Procedure of calculation of isomer shift and quadrupole splitting is shown in details.
• Variants of αFeSi2αFeSi2, most probable after mechanical alloying, are considered.
• Corresponding isomer shifts and quadrupole splittings at iron nuclei are calculated.
• A four-component model for a discrete processing of Mossbauer spectra is proposed.
• The model should help to obtain a detailed information on solid-state reactions.

Former experiments showed that, at early stages, mechanical alloying of iron with silicon produces a disilicide αα-FeSi2. First-principles calculations of isomer shift and quadrupole splitting (electric field gradient) at iron nuclei have been conducted for αα-FeSi2 with account of different defects of lattice. The results obtained have been used for interpretation of a row of recent experiments on mechanical alloying of Si–Fe system. The results on the hyperfine interactions can be used in studying the solid state reactions that occur during mechanical alloying and further annealing, with the help of Mossbauer spectroscopy.