Regensburg 2013 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 61: Liquid & Amorphous Metals I

MM 61.1: Vortrag

Donnerstag, 14. März 2013, 15:45–16:00, H26

Density and viscosity of Cr-Fe-Ni ternary liquid alloys — •Hidekazu Kobatake and Juergen Brillo — Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt, Köln, Germany

Materials of practical relevance, such as Fe-based alloys or stainless steels are mainly ternary combinations of Cr, Fe and Ni. Density and viscosity of these liquid metals are required to simulate the buoyancy forced convection in a liquid during the welding and casting process. Especially, density is required as input parameter for the calculation of other thermophysical properties from the primary measurement data. In this study, the density was measured using electromagnetic levitation as a container-less technique. The shadowgraph of the sample was captured by digital CCD camera and its volume was calculated to by an image processing algorithm to determine the density. In the measured concentration range, the excess volume is positive. The experimentally obtained densities of the ternary system agree well with those calculated according to a thermodynamic mixing rule taking into account contributions from the binary margin systems only. Viscosities, η have been measured by means of a high-temperature oscillating cup viscometer. A cylindrical cup which contains the liquid sample is suspended by a torsion wire and is oscillated around its vertical axis. η was then obtained from the decrement of the oscillation. In the investigated compositional range of the Cr-Ni-Fe system, η as a function of temperature can be described by an Arrhenius law. Isothermal viscosities will be compared to existing thermodynamic models.