Regensburg 2004 – wissenschaftliches Programm
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M: Metallphysik
M 25: Mechanische Eigenschaften III
M 25.2: Vortrag
Donnerstag, 11. März 2004, 10:30–10:45, H4
Computer Simulations of carbon and vacancy related anelasticity in Fe-Al. — •Igor S. Golovin2, Mikhail S. Blanter1, and Hans-Rainer Sinning2 — 1Moscow State Academy of Instrumental Engineering and Information Science, Moscow, Russia — 2TU Braunschweig, Institut fuer Werkstoffe, Langer Kamp 8, D-38106 Braunschweig
Special attention is paid in this research to the interpretation of the S and X peaks (see previous abstracts) in Fe-Al alloys. Peculiarities of carbon diffusion in Fe-Al alloys were studied as a function of interatomic C-Fe, C-Al, C-C, and C-vacancy interactions. Parameters of carbon mobility in solid solution were evaluated using temperature-dependent internal friction measurements (the S and the X relaxation). The ordering of Al atoms enhances C diffusion in the Fe-Al solid solution, while a high vacancy concentration and carbon-vacancy interaction lead to a new relaxation effect with higher activation energy (so-called the X peak). Parameters of the carbon-vacancy interatomic interaction in D03 ordered Fe-Al alloys and correspondingly parameters of the X peak depend on positions which are occupied by vacancies. The employed atom-interaction model is based on the long-range strain-induced (’elastic’) interaction supplemented by a short-range ’chemical’ interaction. The model assumes that the interactions of dissolved atoms affect both the distribution (short-range order) and energies of carbon atoms and consequently the activation energy of their diffusion.