Structural asymmetry in liquid Fe–Si alloys

Abstract

The thermodynamic properties and microscopic structure of liquid Fe–Si alloys at 1873 K were studied by using the regular associated solution model. The model was utilized to determine the complex concentration in a regular associated solution of Fe, Si and Fe₂Si. The complex concentration was then used to calculate the integral excess free energy of mixing, activity, concentration fluctuations in the long-wavelength limit, S_CC (0), and the Warren–Cowley short-range parameter α ₁. The analysis suggests that heterocoordination leading to the formation of complex Fe₂Si is likely to exist in the liquid and is of a strongly interacting nature. The theoretical analysis reveals that the alloy is more ordered towards the Fe-rich region. The observed asymmetry in the properties of mixing of Fe–Si alloys in the molten state is successfully explained on the basis of the regular associated solution model.

Keywords:

• Fe–Si liquid alloy
• microscopic structure
• asymmetry
• complex

Acknowledgements

We are grateful to Prof. L.N. Jha (Head of Central Department of Physics, Tribhuvan University, Nepal) for his valuable suggestions and inspiring discussions. One of the authors (D. Adhikari) is thankful to the University Grant Commission (UGC), Nepal, for providing financial support to pursue the research.