CalPhaD Coffee Lecture TEMPUS and EML: Electromagnetic levitation in microgravity

Abstract

TEMPUS and EML: Electromagnetic levitation in microgravity Tempus and EML are two electromagnetic levitation facilities in microgravity on parabolic flight and ISS as platform. Electromagnetic levitation allows to process materials containerlessly and thus process reactive materials and also reach the metastable state of the undercooled melt. In microgravity heating and positioning can be decoupled and the fluid flows in the sample induced by the heater can be reduced or controlled. As the method uses eddy currents induced from the coil in the sample the sample has to be electrically conductive, a metal or (doped) semiconductor. The facilities allow the investigation of the solidification by recording the solidification process with high speed cameras and analysis of the post mortem microstructure and the measurement of thermophysical properties as surface tension, viscosity, density & electrical conductivity. While in TEMPUS the microgravity time is not sufficient to perform specific heat measurement these can be done on the ISS as the experiments can be performed over a longer time. Both facilities measure the temperature contactlessly by pyrometry and utilize a high-speed camera from the radial view and additionally a second camera observing axially from the top. In TEMPUS additionally an IR camera can be equipped. Both facilities can be operated over a large temperature regime allowing to heat up the sample up to 2100°C and thus can process a broad range of material classes: Glass formers, steels, Ni-based superalloys, Ti alloys, model systems for solidification etc….In the presentation an overview of the performance and evaluation of the experiments as well as information how scientists can perform measurements in the facilities will be given.