Berlin 2024 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 33: Transport in Materials: Diffusion, Conduction of Charge or Heat III
MM 33.4: Vortrag
Mittwoch, 20. März 2024, 11:00–11:15, C 264
Impurity diffusion measurement in liquid Al based alloys using X-ray Radiography — •Masato Shiinoki1, Elke Sondermann1, and Andreas Meyer1,2 — 1Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany — 2Institute Max von Laue - Paul Langevin (ILL), 38042 Grenoble, France
The high accuracy measurements of the impurity diffusion coefficient in liquid metals are indispensable for modeling diffusion theories. The aim of this study is to investigate how the difference in impurity diffusion coefficient in liquid Al is expressed by the hard-sphere model. The impurity diffusion coefficients in liquid Al were measured using the in-situ shear cell method with X-ray radiography technique at 973, 1020, and 1060 K. The concentrations of the two parts of the diffusion couple were chosen to be pure Al and 5 at% Cu, 1 at% Sn, 1 at% Au, 1 at% Ag, and 0.8 at% Bi in Al. The diffusion process was started at connecting each interdiffusion couple after shearing the furnace and concentration profiles were obtained every second. The impurity diffusion coefficients were calculated from the linear fittings to the mean square diffusion distance which is derived from the concentration profiles using Ficks law. The results showed that the excess entropy model using hard sphere reproduced the measured impurity diffusion coefficients in liquid Al better than the hard-sphere model derived from Enskog theory. This excess entropy model reproduces the impurity diffusion coefficients better for other temperatures as well by considering the temperature dependence of the packing density.
Keywords: Liquid Metals; Aluminum based alloys; X-ray Radiography; Shear cell method; Hard-sphere model