Effect of C on vacancy migration in α-iron

Chu Chun Fu; E. Meslin; A. Barbu; F. Willaime; V. Oison

doi:10.4028/3-908451-56-6.157

Effect of C on vacancy migration in α-iron

Chu Chun Fu
, E. Meslin
, A. Barbu
, F. Willaime
, V. Oison

Research output: Contribution to journal › Conference article › peer-review

Abstract

Carbon atoms are always present in Fe-based materials, either as impurities even in high purity samples or as an intrinsic constituent in steels. Density Functional Theory calculations have been performed to study the interaction between C atoms and vacancies (V) in α-Fe. We find that the formation of VC_n complexes is energetically favourable for n ≤ 3, with VC ₂ being the most stable one. The energy gain corresponding to the clustering reaction VC_n-1 +C → VC_n depends mainly on the strength of C-C covalent bonds. The vacancy diffusivity is shown to be significantly modified by the formation of vacancy-carbon complexes, exhibiting non-Arrhenius behaviour. Effective vacancy diffusion coefficients in α-Fe are calculated as a function of temperature and carbon content using a simplified thermodynamic model. The results are discussed in detail in the limiting case of excess of C with respect to vacancies.

Original language	English
Pages (from-to)	157-164
Number of pages	8
Journal	Solid State Phenomena
Volume	139
DOIs	https://doi.org/10.4028/3-908451-56-6.157
Publication status	Published - 1 Jan 2008
Externally published	Yes
Event	Theory, Modeling and Numerical Simulation of Multi-Physics Materials Behavior - Boston, MA, United States Duration: 26 Nov 2007 → 30 Nov 2007

Keywords

Ab initio
Carbon
Diffusion
Equilibrium
Impurity
Iron
Irradiation
Kinetic
Thermodynamic

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10.4028/3-908451-56-6.157

Cite this

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title = "Effect of C on vacancy migration in α-iron",

abstract = "Carbon atoms are always present in Fe-based materials, either as impurities even in high purity samples or as an intrinsic constituent in steels. Density Functional Theory calculations have been performed to study the interaction between C atoms and vacancies (V) in α-Fe. We find that the formation of VCn complexes is energetically favourable for n ≤ 3, with VC 2 being the most stable one. The energy gain corresponding to the clustering reaction VCn-1 +C → VCn depends mainly on the strength of C-C covalent bonds. The vacancy diffusivity is shown to be significantly modified by the formation of vacancy-carbon complexes, exhibiting non-Arrhenius behaviour. Effective vacancy diffusion coefficients in α-Fe are calculated as a function of temperature and carbon content using a simplified thermodynamic model. The results are discussed in detail in the limiting case of excess of C with respect to vacancies.",

keywords = "Ab initio, Carbon, Diffusion, Equilibrium, Impurity, Iron, Irradiation, Kinetic, Thermodynamic",

author = "Fu, \{Chu Chun\} and E. Meslin and A. Barbu and F. Willaime and V. Oison",

year = "2008",

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doi = "10.4028/3-908451-56-6.157",

language = "English",

volume = "139",

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note = "Theory, Modeling and Numerical Simulation of Multi-Physics Materials Behavior ; Conference date: 26-11-2007 Through 30-11-2007",

}

TY - JOUR

T1 - Effect of C on vacancy migration in α-iron

AU - Fu, Chu Chun

AU - Meslin, E.

AU - Barbu, A.

AU - Willaime, F.

AU - Oison, V.

PY - 2008/1/1

Y1 - 2008/1/1

N2 - Carbon atoms are always present in Fe-based materials, either as impurities even in high purity samples or as an intrinsic constituent in steels. Density Functional Theory calculations have been performed to study the interaction between C atoms and vacancies (V) in α-Fe. We find that the formation of VCn complexes is energetically favourable for n ≤ 3, with VC 2 being the most stable one. The energy gain corresponding to the clustering reaction VCn-1 +C → VCn depends mainly on the strength of C-C covalent bonds. The vacancy diffusivity is shown to be significantly modified by the formation of vacancy-carbon complexes, exhibiting non-Arrhenius behaviour. Effective vacancy diffusion coefficients in α-Fe are calculated as a function of temperature and carbon content using a simplified thermodynamic model. The results are discussed in detail in the limiting case of excess of C with respect to vacancies.

AB - Carbon atoms are always present in Fe-based materials, either as impurities even in high purity samples or as an intrinsic constituent in steels. Density Functional Theory calculations have been performed to study the interaction between C atoms and vacancies (V) in α-Fe. We find that the formation of VCn complexes is energetically favourable for n ≤ 3, with VC 2 being the most stable one. The energy gain corresponding to the clustering reaction VCn-1 +C → VCn depends mainly on the strength of C-C covalent bonds. The vacancy diffusivity is shown to be significantly modified by the formation of vacancy-carbon complexes, exhibiting non-Arrhenius behaviour. Effective vacancy diffusion coefficients in α-Fe are calculated as a function of temperature and carbon content using a simplified thermodynamic model. The results are discussed in detail in the limiting case of excess of C with respect to vacancies.

KW - Ab initio

KW - Carbon

KW - Diffusion

KW - Equilibrium

KW - Impurity

KW - Iron

KW - Irradiation

KW - Kinetic

KW - Thermodynamic

U2 - 10.4028/3-908451-56-6.157

DO - 10.4028/3-908451-56-6.157

M3 - Conference article

AN - SCOPUS:47349113457

SN - 1012-0394

VL - 139

SP - 157

EP - 164

JO - Solid State Phenomena

JF - Solid State Phenomena

T2 - Theory, Modeling and Numerical Simulation of Multi-Physics Materials Behavior

Y2 - 26 November 2007 through 30 November 2007

ER -

Effect of C on vacancy migration in α-iron

Abstract

Keywords

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