Springer LINK: The European Physical Journal B - Abstract Volume 3 Issue 2 (1998) pp 175-178

The European Physical Journal B

ISSN: 1434-6028 (printed version)
ISSN: 1434-6036 (electronic version)

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Abstract Volume 3 Issue 2 (1998) pp 175-178

Methodological aspects of calculations of the thermodynamic factor in interdiffusion

S. Dorfman (1) (a), D. Fuks (2), H. Mehrer (3)

(1) Department of Physics, Technion, 32000 Haifa, Israel
(2) Materials Engineering Department, Ben-Gurion University of the Negev, P.O.Box 653, 84105 Beer Sheva, Israel
(3) Institut für Metallforschung, Universität Münster, Wilhelm-Klemm-Strasse 10, 48149 Münster, Germany

Received: 2 September 1997 / Accepted: 16 September 1997

Abstract: Self-diffusion can be studied in binary systems for which appropriate radioisotopes for both constituents of the alloy are available. With respect to the Fe-Al system suitable radioisotopes are available for the Fe component (e.g. ⁵⁹Fe) but not for Al. In the framework of the Boltzmann-Matano method further insight into the diffusion behaviour of Fe-Al intermetallics can be gained from interdiffusion experiments. The interdiffusion coefficient is related via the modified Darken equation to the tracer diffusivities of the constituents. The thermodynamic factor $\Phi$ entering the Darken equation is proportional to the second derivative of the Gibbs free energy, G, of the alloy on the molar fraction of one of the components. These relations can be used to deduce the tracer diffusivity of Al provided that the tracer diffusivity of Fe, the interdiffusion coefficient and the thermodynamic factor are known. The mixing energy, which enters G, could be calculated on the basis of the thermodynamical data or by means of non-empirical calculations. We suggest for the latter ab initio calculations the use of modern non-empirical methods.

PACS. 64.70.-p Specific phase transitions[:AND:] 65.50.+m Thermodynamic properties and entropy - 66.30.-h Diffusion in solids

(a) email: phr24ds@techunix.technion.ac.il

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