The measurement of viscosity of alloys - a review of methods, data and models

Values of the viscosities of liquid metals are important in the prediction of fluid flow in many metallurgical manufacturing processes. This paper describes a number of methods used to measure the viscosity of liquid metals, including capillary, oscillating vessel, rotational bob or crucible, oscillating plate, draining vessel, levitation using the damping of surface oscillations and acoustic methods. A number of models used to estimate viscosity for elements, the temperature dependence of viscosity, and viscosity of multicomponent systems are also given, including the Andrade equation, Arrhenius equation, Hildebrand's free volume theory, Chhabra models, Moelwyn-Hughes model and thermodynamic models. The scatter of data available in the literature are highlighted by comparing two reviews of data for elements.