Alexander Gerst installing the Electromagnetic Levitator
Temperature-dependent properties of the molten material, such as viscosity, surface tension, specific heat, coefficient of thermal expansion and electrical conductivity are determined using an Electromagnetic Levitator (EML). It was developed on behalf of the DLR Space Administration and ESA. This facility was installed and commissioned in the Columbus Laboratory by Alexander Gerst in 2014.
Credit:
NASA/ESA
One of the focal points of research onboard the International Space Station ISS is the investigation of crystal growth in metal alloys. Under microgravity conditions, differences in density in the molten material no longer occur. Mixing and thus mass transport through convection therefore play no part. What remains is the component of the mass transport that is determined only by the motion of the molecules themselves, known as diffusion.
TRANSPARENT-1 will help researchers understand the behaviour of molten material as it solidifies and predict it as precisely as possible. This will allow for better simulation of casting processes on Earth. Two furnaces are used in the Materials Science Laboratory (MSL) to investigate crystal growth in metallic samples – the Low Gradient Furnace (LGF) and the Solidification and Quenching Furnace (SQF). The solidification of an organic model alloy of neopentyl glycol and camphor is to be investigated in situ in the new TRANSPARENT-1 facility in the Materials Science Glovebox. The experiments are carried out, monitored and evaluated on the ISS in close collaboration with researchers from the ACCESS Institute in Aachen.
Temperature-dependent properties of the molten material, such as viscosity, surface tension, specific heat, coefficient of thermal expansion and electrical conductivity are determined using an Electromagnetic Levitator (EML). It was developed on behalf of the DLR Space Administration and ESA. This facility was installed and commissioned in the Columbus Laboratory by Alexander Gerst in 2014. High-melting-point alloy samples can be levitated via weak electromagnetic fields in the heating unit and melted by a uniform, high-frequency electromagnetic dipole field. This prevents microscopic contaminants from penetrating the molten material, which could lead to earlier solidification, as is often the case with melting processes on Earth. Decoupling heating from positioning is only possible under microgravity conditions and leads to significantly less convection in the molten material.
The data collected on the ISS is in great demand for the purpose of improving computer models of industrial casting processes for high-technology materials such as innovative, lighter aircraft turbine blades and engine casings.
