Materials Research in Reduced Gravity: Thermophysical Properties II
Sponsored by: TMS Extraction and Processing Division, TMS Materials Processing and Manufacturing Division, TMS: Process Technology and Modeling Committee
Program Organizers: Robert Hyers, Worcester Polytechnic Institute; Douglas Matson, Tufts University; Michael Sansoucie, Nasa Marshall Space Flight Center; Shaun McFadden, Ulster University; Jonghyun Lee, Iowa State University; Wilhelmus Sillekens, European Space Agency; Takehiko Ishikawa, Japan Aerospace Exploration Agency
Thursday 8:30 AM
February 27, 2020
Room: 18
Location: San Diego Convention Ctr
Session Chair: Jonghyun Lee, Iowa State University; Markus Mohr, Ulm University
8:30 AM Cancelled
Effect of External Force on Surface Oscillation Damping of Levitated High-temperature Droplet: Masahito Watanabe1; 1Gakushuin University
We examined the effect of external force on surface oscillation damping for low viscosity high-temperature liquids, such as Fe and/or Fe alloys using an acoustic levitation (ADL) device. On ADL technique, the amplitude of surface oscillation of droplet is modified by the applied acoustic signal power. For the case of molten oxides, the surface oscillation damping was not much affected by the applied acoustic signal power. We find that the surface oscillation decay time of low viscosity liquids depends on the oscillation amplitude. The relationship between the decay time and the amplitude of surface oscillation well described by the curve using the Reynolds number. This means that the surface oscillation damping of low viscosity liquids are sensitivity of internal flow conditions. We discuss from the experimental results the effect of external force on the surface oscillation damping for low viscosity high-temperature liquids for deciding microgravity experimental conditions.
8:50 AM
Viscosity Measurement of Liquid Alloys in Microgravity and Experiment Parameters Optimization: Xiao Xiao1; Douglas Matson2; 1DLR; 2Tufts University
Viscosity of selected alloys are measured using ISS-EML facility on the International Space Station. Through oscillating droplet method, the damping behavior of pulse induced surface oscillation of electromagnetically levitated molten samples are characterized and used to determine the apparent eddy viscosity and molecular viscosity based on the internal flow conditions. Experiment parameters are further optimized by assigning appropriate pulse amplitude and testing temperature allowing more effective viscosity measurement using the ISS-EML facility in microgravity conditions.
9:10 AM
Containerless Measurement of Thermophysical Properties of Ni-based Superalloys LEK94, MC2 and CMSX-10 in the Liquid Phase on Board the International Space Station: Markus Mohr1; Rainer Wunderlich1; Hans Fecht1; 1Ulm University
Nickel-based superalloys combine mechanical properties beneficial for applications in high temperature environments, such as high strength, creep resistance and toughness. Therefore, typical applications are in turbines for land-based power generators as well as in aircraft engines. Nowadays casting developments are accompanied by simulations of the heat and material flow in the melt. Such models require precise input data of thermophysical properties in the solid and liquid phase. The high solution reactivity of the melts makes measurement of surface tension, viscosity and specific heat of liquid metals a challenge. The method of choice is electromagnetic levitation, a containerless method. However, gravitational forces have to be absent to obtain a spherical droplet with controlled fluid flow conditions. We will present and discuss measurements of thermophysical properties, performed in the Material Science Laboratory Electromagnetic Levitator (ISS-EML) on board the European Space Laboratory Columbus in the international space station (ISS).
9:30 AM
Modeling Magnetohydrodynamics in Microgravity Electromagnetic Levitation Experiments: Gwendolyn Bracker1; Robert Hyers1; 1University of Massachusetts
Electromagnetic levitation experiments provide a powerful tool that allows for the study of nucleation, solidification and growth in a containerless processing environment. However, in experiments using the oscillating drop method, it is important to understand the magnetohydrodynamic flow within the sample to ensure valid measurements. In opaque liquid metal drops it is not usually possible to directly measure and characterize the flow within the drop; however, the flow can be indirectly measured through modeling which relates the experimental parameters with the thermophysical properties to calculate the properties of the flow. To ensure clean measurements, modeling should be done during the design phase to evaluate the experimental parameters and the resulting flow. This will allow parameters to be restricted to a range that will provide flow that will result in valid measurements.
9:50 AM
Effect of Inert Gas Atmosphere on Evaporation Losses and Density Measurement for Electromagnetically Levitated Superalloys: Jannatun Nawer1; Stéphane Gossé2; Michael SanSoucie2; Douglas Matson1; 1Tufts University; 2CEA Saclay
Mass evaporation changes the composition of alloys during melting and annealing affecting their final product performance. The use of inert gas significantly reduces the evaporation, so a mathematical model based on Langmuir’s equation was developed to track mass loss of each species in the alloy composition during the measurement of thermo-physical properties in ISS-EML. Two Ni-based super alloys, CMSX-10 and LEK-94 were investigated to predict the dynamic mass loss and track the potential for composition shifts throughout each thermal cycle. Conducting experiments in an inert shielding-gas environment virtually eliminates composition shifts (less than 1%) due to differential relative evaporation and the composition is maintained within the desired limits. Knowledge of the activities of the various species of these alloys as a function of temperature increases the accuracy of density measurements because dynamic mass is now known.
10:10 AM Break
10:40 AM
Thermophysical Properties of SiGe Melts Measured on Board the ISS: Yuansu Luo1; Bernd Damaschke1; Georg Lohöfer2; Konrad Samwer1; 1I.Physics Institute University Goettingen; 2Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), D-51170 Cologne, Germany
Processing semiconductors based on EML is a challenge due to their poor electrical conductivity. In framework of the ESA project, first attempts with highly doped Si1-xGex were made on ISS. Initial results indicate that the samples could be melted, overheated by ~350°C and cooled down in 350mbar Ar. A large undercooling of ~240°C was observed thereby, followed with a quasi-homogenous nucleation. During cooling high-resolution videos were taken and digitalized to evaluate the density and thermal expansion. The surface tension and viscosity were measured by the oscillating drop technique and the electrical conductivity by a special sample coupling electronics. We found a nonlinear thermal expansion suggesting a many-body effect in the liquid beyond the regular pair potential and a strongly enhanced viscosity likely due to the internal turbulence flow. We acknowledge the access to the ISS-EML, undertaking of the ESA & DLR Space Administration, and the financial support of BMWi50WM1750.
11:00 AM
Thermo-physical Properties of Fe-Si Alloys under Microgravity: Antonia Betzou1; Markus Mohr2; Rainer Wunderlich2; Begona Santillana3; Hans Fecht2; Sridhar Seetharaman4; Prakash Srirangam1; 1Wmg, University Of Warwick; 2University of Ulm; 3TaTa Steel Europe; 4Colarado School of Mines
Thermo physical properties of liquid steel play an important role in casting and solidification processes. The investigation of these properties such as viscosity and surface tension could lead to the prediction of liquid metal flow in casting and solidification and thus the efficient control of these metallurgical processes. Measuring thermos physical properties in microgravity conditions can eliminate any influences on the container walls and, thus, provide pure alloy values. In this study, viscosity and surface tension of Fe-10% Si alloy was measured by conducting experiments using an electromagnetic levitation device on board a parabolic flight airplane. Also, the viscosity values were measured under terrestrial conditions using a high temperature rheometer. The viscosity of Fe-10% Si alloy was found to be 8.3 mPa.s, while the viscosity of the same alloy under terrestrial conditions was found to be 7.5 mPa.s. The discrepancy in these viscosity values needs to be further investigated.
11:20 AM
Computational Fluid Dynamics Modeling of Oscillation Damping of Compound Liquid Droplets: Ali Rabeh1; Makrand Khanwale1; Baskar Ganapathysubramian1; Robert Hyers2; Jonghyun Lee1; 1Iowa State University; 2University of Massachusetts
Interfacial tension between molten slags and steel is being measured by the extended oscillating droplet method using the Electrostatic Levitation Furnace aboard the international space station. The oscillation and damping behavior of a levitated core-shell compound droplet is captured using a photo sensor. The obtained damping curves are analyzed to extract two oscillation frequencies by which the interfacial tension is to be calculated. A numerical model has been developed to predict the damping of the compound droplet. The developed model is being utilized to design space experiments and interpret the results downloaded from the international space station. This presentation introduces our recent efforts on the development and improvement of the numerical model to support the upcoming space experiments.