Abstract
A thermodynamic model was developed for the Fe-Si solid phases and applied to the calculation of high-pressure phase equilibria and thermophysical properties of Fe-Si alloys. The model is based on integration of available CALPHAD (CALculation of PHAse Diagrams) description for the Fe-Si system at ambient pressure with a composition-dependent equation of state, the parameters of which were fitted to available experimental data. At inner-core pressures and temperatures a two-phase structure is predicted, consisting of almost pure hcp-Fe and a stoichiometric CsCl-structured FeSi. Other outcomes of the model include predictions of pressure-enhanced B 2 ordering in α-Fe-Si alloys and an anomalously high thermal expansion of the CsCl-structured FeSi compound at ambient pressure, connected with temperature-effect on its degree of order.
| Original language | English |
|---|---|
| Pages (from-to) | 289-298 |
| Number of pages | 10 |
| Journal | Physics of the Earth and Planetary Interiors |
| Volume | 172 |
| Issue number | 3-4 |
| DOIs | |
| State | Published - 1 Feb 2009 |
Keywords
- Equation of state
- High pressure
- Iron
- Phase diagram
- Silicon
- Thermodynamics
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Geophysics
- Physics and Astronomy (miscellaneous)
- Space and Planetary Science