Measurements of the Viscosity of the Undercooled Melts Under the Conditions of Microgravity and Supporting MHD Calculations

Abstract

This report covers the work to support the measurement of the surface tension and viscosity of undercooled metals with the TEMPUS as a part of the IML-2 mission. This work consisted of two parts. First was the ground-based research program, whose purpose was to establish the feasibility of the flight program and to establish the knowledge base necessary to plan a successful flight program. Analytical calculations established a fundamental understanding of the problem, and then a more rigorous program of numerical calculations was employed in the development of the experimental program. The second part of the covered research was the actual flight program, developed in close collaboration with Prof. Egry. A metal sphere was levitated and melted, and then set oscillating by 'squeezing' it with the magnetic field. The droplet's oscillations were recorded on videotape and digital image analysis was employed in reduction of the data. The experiment was successful because surface tension measurements were obtained for the gold and gold-copper alloy samples. This data provides unique experimental evidence in support of theories about electromagnetic levitation on the ground. Because of unforeseen difficulties with stability of liquid samples in TEMPUS, the viscosity measurements were not possible, but the data collection and analysis techniques were well proven in this mission. Further research is being conducted regarding the measurement of viscosity by this technique