EML – Electromagnetic levitator onboard the ISS: investigation of thermophysical properties & solidification of liquid metals

Kurzfassung

EML is an electromagnetic levitation facility of the European Space Agency (ESA) onboard the ISS for the containerless processing of conductive materials under microgravity conditions, which is now since 10 years in operation in the Columbus module. Due to the absence of container walls the meta stable state of the undercooled melt can be reached and investigated. The facility allows the measurement of thermophysical properties as surface tension, viscosity, density, specific heat, emissivity & electrical conductivity. Solidification processes can be investigated by the measurement of the growth velocities, the delay time between metastable and stable phase formation and the investigation of the microstructure of the solidified sample after the experiments. In microgravity heating & positioning can be decoupled, so that measurements can be performed at reduced field strengths or the field and electromagnetic stirring can be used as parameter for the measurements. The presentation will give an overview of the technical aspects of the facility, the measurement principles and some results from the ISS experiments. It will be shown how the experiments are planned and performed and will present an overview of the experiments in the last decade.