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 properties of the solid, solid + liquid, and liquid phases are essential for effective computer simulation. Commercially available instruments can measure many of the required properties of molten metals (e.g., transformation temperatures, thermal conductivity, specific heat, latent heat, and density). However, there are no commercially available instruments to characterize several important thermophysical properties (e.g., emissivity, electrical resistivity, surface tension, and viscosity). Although the literature has numerous examples of measurements of surface tension using the sessile drop and the 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 and its application to characterizing the viscosity of fully molten industrial alloys. The theory behind the oscillating cup technique is reviewed, and the design details of the current instrument are discussed. In addition, experimental data of the viscosity of several nickel-based superalloys are preseInted.