Thermophysical Properties of Advanced Ni-Based Superalloys in the Liquid State Measured on Board the International Space Station

Advanced nickel-based superalloys combine excellent high-temperature mechanical strength, creep resistance, and toughness, and therefore find applications in next-generation aircraft engines and turbines for land-based power generators. The related fabrication processes are complex, time consuming, and costly, making it necessary to perform supporting computer simulations of the heat and material flow in the melt before and during crystallization. Such models are based on reliable thermophysical property data in the solid and liquid phase. However, measurements of surface- and volume-dependent properties, such as liquid surface tension, viscosity, and specific heat of these complex liquid metal alloys, are very challenging, due to the melts high chemical reactivity at temperatures of interest. The method of choice is electromagnetic levitation, a containerless method. The measurements of surface tension, viscosity, mass density, and specific heat capacity, performed in the electromagnetic levitator (EML) on board the Space Laboratory Columbus in the International Space Station (ISS), are presented and discussed.