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Atomic, Electronic, and Magnetic Structure of Iron-Based Sigma-Phases

Published online by Cambridge University Press:  26 February 2011

Pavel A. Korzhavyi
Affiliation:
Department of Materials Science and Engineering, Royal Institute of Technology (KTH), SE-100 44 Stockholm, SWEDEN
Bo Sundman
Affiliation:
Department of Materials Science and Engineering, Royal Institute of Technology (KTH), SE-100 44 Stockholm, SWEDEN
Malin Selleby
Affiliation:
Department of Materials Science and Engineering, Royal Institute of Technology (KTH), SE-100 44 Stockholm, SWEDEN
Börje Johansson
Affiliation:
Department of Materials Science and Engineering, Royal Institute of Technology (KTH), SE-100 44 Stockholm, SWEDEN Condensed Matter Theory Group, Department of Physics, Uppsala University, SE-751 21 Uppsala, SWEDEN.
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Abstract

A combination of ab initio total energy calculations with Calphad approach is applied to model the site occupancy and thermodynamic properties of the Fe-Cr, Co-Cr, Fe-V, and Fe-Mo binary sigma-phases as a function of composition and temperature. For each binary sigma-phase the parameters of the model are the ab initio calculated total energies of so-called end-member compounds, which represent all the 25=32 variants of complete occupancy of each of the five crystallographically inequivalent sites by one or the other alloy component. The paramagnetic state of the sigma-phases has been taken into account within the disordered local moment approach. The Fe and Co atoms are found to retain high spin moments when they occupy high-coordination-number sites in the structure. Using our model we were able to reproduce the experimentally observed site occupancy in the FeCr sigma-phase. The calculated site occupancies in the Co-Cr, Fe-V, and Fe-Mo sigma-phases are also presented and discussed.

Type
Research Article
Copyright
Copyright © Materials Research Society 2005

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References

REFERENCES

1. Bergman, G. and Shoemaker, D. P., Acta Cryst. 7, 857 (1954).Google Scholar
2. Hall, E. O. and Algie, S. H., Metallurgical Reviews 11, 61 (1966).Google Scholar
3. Yakel, H. L., Acta Cryst. B39, 20 (1983).Google Scholar
4. Hillert, M., J. Alloy Compd. 320, 161 (2001).Google Scholar
5. Fries, S. G. and Sundman, B., Phys. Rev. B 66, 012203 (2002).Google Scholar
6. Berne, C., Sluiter, M., Kawazoe, Y., Hansen, T., and Pasturel, A., Phys. Rev. B 64, 144103 (2001).Google Scholar
7. Sluiter, M. H. F., Esfarjani, K., and Kawazoe, Y., Phys. Rev. Lett. 75, 3142 (1995).Google Scholar
8. Havránková, J., Vřeštál, J., Wang, L. G., and Šob, M., Phys. Rev. B 63, 174104 (2001).Google Scholar
9. Ruban, A. V. and Skriver, H. L., Comp. Mat. Sci. 15, 119 (1999).Google Scholar
10. Perdew, J. P. and Wang, Y., Phys. Rev. B 45, 13244 (1992).Google Scholar
11. Vitos, L., Johansson, B., Kollàr, J., and Skriver, H. L., Phys. Rev. B 62, 10046 (2000).Google Scholar
12. Gyorffy, B. L., Pindor, A. J., Staunton, J. B., Stocks, G. M., and Winter, H., J. Phys. F 15, 1337 (1985).Google Scholar
13. Perdew, J. P., Burke, K., and Ernzerhof, M., Phys. Rev. Lett. 77, 3865 (1996).Google Scholar
14. Simdyankin, S. I., Taraskin, S. N., Dzugutov, M., and Elliott, S. R., Phys. Rev. B 62, 3223 (2000).Google Scholar
15. Downie, D. B. and Martin, J. F., J. Chem. Thermodynamics 16, 743 (1984).Google Scholar