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Configurational the...
Configurational thermodynamics of Fe-Ni alloys at Earths core conditions
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- Ekholm, Marcus (author)
- Linköpings universitet,Teoretisk Fysik,Tekniska högskolan
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- Mikhaylushkin, Arkady (author)
- Linköpings universitet,Teoretisk Fysik,Tekniska högskolan
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- Simak, Sergey (author)
- Linköpings universitet,Teoretisk Fysik,Tekniska högskolan
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- Johansson, Börje (author)
- KTH,Tillämpad materialfysik,Royal Institute Technology KTH
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- Abrikosov, Igor (author)
- Linköpings universitet,Teoretisk Fysik,Tekniska högskolan
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(creator_code:org_t)
- Elsevier, 2011
- 2011
- English.
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In: Earth and Planetary Science Letters. - : Elsevier. - 0012-821X .- 1385-013X. ; 308:1-2, s. 90-96
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Abstract
Subject headings
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- By means of ab-initio calculations, we perform an analysis of the configurational thermodynamics, effects of disorder, and structural energy differences in Fe-Ni alloys at the pressure and temperature conditions of the Earths core. We show from ab-initio calculations that the ordering energies of fcc and hcp-structured Fe-Ni solid solutions at these conditions depend sensitively on the alloy configuration, i.e., on the degree of chemical disorder, and are on a scale comparable with the structural energy differences. From configurational thermodynamic simulations we find that a distribution of Fe and Ni atoms in the solutions should be very close to completely disordered at these conditions. Using this model of the Fe-Ni system, we have calculated the fcc-hcp structural free energy difference in a wide pressure-temperature range of 120-360 GPa and 1000-6600K. Our calculations show that alloying of Fe with Ni below 3000 K favours stabilisation of the fcc phase over the hcp, in agreement with experiments. However, above 3000 K the effect is reversed, and at conditions corresponding to those of the Earths inner core, Ni acts as an agent to stabilise the hcp phase.
Subject headings
- NATURVETENSKAP -- Fysik -- Den kondenserade materiens fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Condensed Matter Physics (hsv//eng)
Keyword
- Earths inner core
- Fe-Ni alloy
- ab-initio calculations
- crystal structure
- TECHNOLOGY
- TEKNIKVETENSKAP
- Condensed matter physics
Publication and Content Type
- ref (subject category)
- art (subject category)
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