Dresden 2009 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 35: Poster Session II
MM 35.14: Poster
Mittwoch, 25. März 2009, 16:30–18:30, P4
Liquid Cu-Ni-Fe: Molar volume and short range order. — •Jürgen Brillo1, Ivan Egry1, Louis Hennet2, Mirko Kehr3, and Irina Pozdnyakova2 — 1Institut für Materialphysik im Weltraum, Deutsche Zentrum für Luft- und Raumfahrt, Linder Höhe, 51170 Köln — 2CRMHT, CNRS, 1D, Ave. de la Recherche Scientifique, 45071 Orleans Cedex 2, France — 3TU Chemnitz, Institut für Physik, Professur Röntgen- und Neutronendiffraktometrie, Reichenhainer Straße 70, 09216 Chemnitz
The molar volume and the atomic short range order were measured for liquid Cu-Ni-Fe binary and ternary alloys.
All experiments were performed containerlessly using the technique of electromagnetic levitation. The molar volume was determined by optical dilatometry and the atomic short range order was obtained from x-ray diffraction experiments carried out at ESRF in Grenoble.
The results are discussed in view of the volumetric mixing behaviour of the system. It was found that the excess molar volumes of the ternary alloys and the binary Cu-Fe alloys are similar and strongly positive while it is negative for Cu-Ni.
This was partly confirmed by the x-ray scattering experiments which exhibit similarities in the short range order of Cu-Fe and Cu-Fe-Ni: In these systems, the nearest neighbour distance, R, is almost identical and does not vary with the composition whereas R is significantly smaller and increases monotonically with the Cu-concentration in Cu-Ni. There are also hints that in Cu-Fe and Cu-Fe-Ni the molar volume is mainly determined by the first shell coordination number.