Viscosity measurements of industrial alloys using the oscillating cup technique

Molten metal processing can be effectively simulated using state-of-the-art computer algorithms, and manufacturers increasingly rely upon these tools to optimize the design of their operations. Reliable thermophysical propert ies of the solid. solid + liquid, and liquid phases are essential for effec tive computer simulation. Commercially available instruments can measure ma ny of the required properties of molten metals (e.g., transformation temper atures, thermal conductivity, specific heat, latent heat, and density). How ever, there are no commercially available instruments to characterize sever al important thermophysical properties (e.g., emissivity, electrical resist ivity, surface tension, and viscosity). Although the literature has numerou s examples of measurements of surface tension using the sessile drop and th e oscillating drop techniques, literature references are sparse with regard to measurements of emissivity, electrical resistivity, and viscosity. The present paper discusses the development of an oscillating cup viscometer an d its application to characterizing the viscosity of fully molten industria l alloys. The theory behind the oscillating cup technique is reviewed, and the design details of the current instrument are discussed. In addition, ex perimental data of the viscosity of several nickel-based superalloys are pr esented.