Ab initio calculations of elastic properties of bcc Fe-Mg and Fe-Cr random alloys
2009 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 79, no 22, 224201- p.Article in journal (Refereed) Published
Using the ab initio exact muffin-tin orbitals method in combination with the coherent-potential approximation, we have calculated the elastic parameters of ferromagnetic Fe1-mMgm (0 < m < 0.1) and Fe1-cCrc (0 < c < 0.2) random alloys in the body-centered cubic (bcc) crystallographic phase. Results obtained for Fe1-cCrc demonstrate that the employed theoretical approach accurately describes the experimentally observed composition dependence of the polycrystalline elastic moduli of Fe-rich alloys encompassing maximum similar to 10% Cr. The elastic parameters of Fe-Cr alloys are found to exhibit anomalous composition dependence around 5% Cr. The immiscibility between Fe and Mg at ambient conditions is well reproduced by the present theory. The calculated lattice parameter for the Fe-Mg regular solid solution increases by similar to 1.95% when 10% Mg is introduced in Fe, which corresponds approximately to 11% decrease in the average alloy density, in perfect agreement with the experimental finding. At the same time, we find that all of the elastic parameters of bcc Fe-Mg alloys decrease almost linearly with increasing Mg content. The present results show a much stronger alloying effect for Mg on the elastic properties of alpha-Fe than that for Cr. Our results call for further experimental studies on the mechanical properties of the Fe-Mg system.
Place, publisher, year, edition, pages
2009. Vol. 79, no 22, 224201- p.
ab initio calculations, elastic moduli, ferromagnetic materials, iron alloys, lattice constants, linear muffin-tin orbital method, magnesium alloys, solubility
IdentifiersURN: urn:nbn:se:uu:diva-128376DOI: 10.1103/PhysRevB.79.224201ISI: 000267699300045OAI: oai:DiVA.org:uu-128376DiVA: diva2:331460