Carbon-vacancy interactions in B.C.C. iron

Results have been taken from recent work on the thermodynamics of vacancy-interstitial inter-actions in metals in order to elucidate the effect of such interactions upon the thermodynamic functions and kinetic behavior of the C–b.c.c. iron system. It is shown that even with C–vacancy binding enthalpies (e) as high as 1 eV, such interactions would not have an observable effect on the thermodynamic functions of the C atoms nor upon C diffusion or Fe-atom diffusion. However a consideration of positron annihilation data indicates that e must be ≦ 0.75 eV. Neue Ergebnisse bezuglich der Thermodynamik der Wechselwirkungen zwischen Leerstellen und interstitioncllen Fremdatomen werden verwendet, um die Effekte solcher Wechselwirkungen auf die Thermodynamik und Kinetik der C–(k.r.z.)Fe-Losungen zu untersuchen. Es wird gezeigt, das selbst wenn die C–Leerstelle-Bindungsenthalpie (e) 1 eV betragt, solche Wechselwirkungen mesbare Effekte weder auf die thermodynamischen Funktionen der gelosten C-Atome, noch auf das Diffusionsverhalten der C- und Fe-Atome ausuben wurden. Eine Berucksichtigung der vorhandenen Positronannihilationsdaten zeigt aber, das e unterhalb des Hochstwertes 0,75 eV liegt.

[1]  R. Mclellan.  The diffusivity of lattice atoms in dilute interstitial solid solutions , 1988 .

[2]  R. Mclellan.  The thermodynamics of interstitial-vacancy interactions in solid solutions , 1988 .

[3]  F. Walz,et al.  Binding enthalpies of carbon-vacancy complexes in α-Fe and their compatibility with different annealing models† , 1987 .

[4]  F. Faupel,et al.  Carbon-vacancy binding in NiC alloys , 1986 .

[5]  A. Vehanen,et al.  Vacancies and carbon impurities inα- iron: Electron irradiation , 1982 .

[6]  L. Schepper,et al.  The influence of small amounts of interstitial solute atoms on the determination of the activation energies for self‐diffusion and vacancy formation in α‐iron , 1981 .

[7]  W. Triftshäuser,et al.  Phase transformations and vacancy formation energies of transition metals by positron annihilation , 1979 .

[8]  S. M. Kim,et al.  Vacancy formation energy in iron by positron annihilation , 1978 .

[9]  A. Seeger,et al.  On the interaction of foreign interstitial atoms with vacancies in α-Fe and group-V transition metals☆ , 1977 .

[10]  H. Schaefer,et al.  Vacancy formation in iron investigated by positron annihilation in thermal equilibrium , 1977 .

[11]  H. Mehrer,et al.  Self-diffusion in ferromagnetic α-iron , 1977 .

[12]  R. Mclellan,et al.  The thermodynamic properties of carbon in body-centered cubic iron , 1971 .

[13]  M. Wuttig.  On the activation entropy of interstitial diffusion in B.C.C. iron , 1971 .

[14]  S. J. Rothman,et al.  Isotope Effect in Self-Diffusion in Zinc , 1967 .

[15]  A. Damask,et al.  Kinetics of carbon precipitation in irradiated iron—III. Calorimetry , 1964 .

[16]  R. Borg,et al.  The diffusion of cobalt and iron in pure delta iron , 1963 .

[17]  Morris Cohen,et al.  Self diffusion in iron , 1961 .