Materials Research in Reduced Gravity: Solidification (Levitation) / Thermophysical Properties (Levitation)
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Solidification Committee, TMS: Process Technology and Modeling Committee
Program Organizers: Wilhelmus Sillekens, European Space Agency; Michael Sansoucie, Nasa Marshall Space Flight Center; Robert Hyers, Worcester Polytechnic Institute; Douglas Matson, Tufts University; Gwendolyn Bracker, DLR Institute of Materials Physics in Space
Thursday 8:30 AM
March 23, 2023
Room: 30B
Location: SDCC
Session Chair: Michael Sansoucie, Nasa Marshall Space Flight Center; Kaihua Ji, Northeastern University
8:30 AM
Containerless Solidification of Al-22.5wt%Cu in Reduced Gravity Using the ISS-EML: Jonas Valloton1; Sven Vogel2; Hani Henein1; 1University of Alberta; 2Los Alamos National Laboratory
A hypoeutectic Al-22.5wt%Cu sample was processed using the Electro-Magnetic Levitator on board of the International Space Station within the frame of the European Space Agency project NEQUISOL. Several solidification cycles were carried out, with the last cycle yielding a primary undercooling of 20 K and a eutectic undercooling of 35 K. After being returned to Earth, preliminary investigation of the surface of the sample showed unexpected features. The growth direction of the visible dendrites seemed to differ from the characteristic <100> expected of primary α-Al. Furthermore, two distinct eutectic morphologies were observed: a typical lamellar eutectic, as well as an undulated structure, akin to what is formed in rapidly solidified eutectic Al-33wt%Cu droplets. Additional non-destructive techniques will be used: neutron diffraction for phase analysis and X-ray tomography for microstructure evaluation. Then a full metallographic analysis will be performed using optical and electron microscopy and Electron BackScattered Diffraction.
8:50 AM Cancelled
Anomalous Kinetics of Rapidly Solidified Al-rich Al-Ni Alloys: Peter Galenko1; 1Friedrich Schiller University Jena
A monotonically increasing crystal growth velocity with increasing undercooling is usually expected. By contrast to this general theoretical statement, Al-Ni alloys show an anomalous solidification behavior: the solid-liquid interface velocity slows down as the undercooling increases. In the light of measurements in microgravity with an Al-Ni alloys results confirming this anomalous behavior as an unexpected trend in solidification kinetics are presented. The measurements show multiple nucleation events forming the growth front, a mechanism summarized with detailed analysis over a wider range of concentrations. The obtained data directly demonstrate that the growth front does not consist of dendrite tips, but of newly forming nuclei propagating along the sample surface. Theoretical analysis on intensive nucleation ahead of crystal growth front is made. Quantitative calculations confirm the interpretation of experimentally observed propagation of the recalescence front and obtained data on the microstructure of droplets solidified in electromagnetic levitation facility.
9:10 AM
Transient Convective Transport during Undercooled Droplet Solidification: Andrew Kao1; Valdis Bojarevics1; Catherine Tonry1; Koulis Pericleous1; 1University of Greenwich
Undercooled solidification of droplets allows us to understand the very fundamentals of solidification. However, convective transport can have a significant impact on the evolution of the microstructure. To achieve undercooling, electromagnetic levitation is necessary under terrestrial conditions and that inevitably leads to gravity-driven fluid flow that alters microstructure. While in microgravity, this effect is much weaker and leads to a clearer understanding of how solidification progresses. In this paper we couple the transient coupled behaviour as the microstructure solidifies to the fluid flow that is present at nucleation, to understand how critical measurements, such as tip growth velocity, may change. This effect is especially important in the low undercooled regime where fluid flow has time to adapt to the solidification front. A parallel numerical model coupling an enthalpy-based method for solidification to a Lattice Boltzmann method for fluid flow is used to simulate this problem.
9:30 AM
Influence of Undercooling and Convective Stirring on Phase Transformations in Electromagnetically Levitated Fe-Co: Brian Stanford1; Olga Shuleshova2; Douglas Matson1; 1Tufts University; 2Ifw Dresden
This work is motivated by a desire to achieve a wholistic understanding of the behavior of undercooled metal alloys to control microstructural evolution during casting processes in both ground and space-based environments. Of appreciable interest is the influence of stirring on phase selection during solidification. The space electromagnetic levitation (ISS-EML) platform onboard the International Space Station provides the unique ability to select a wide range of melt convection conditions while observing transformation kinetics in a containerless manner using high speed video and radiation pyrometry. In Fe-Co alloys, higher undercooling and increased stirring promote nucleation of the stable austenitic phase which forms after primary solidification of the metastable ferrite. The Retained Damage Model (RDM) uses optimized parameters collected from undercooled ground-based electrostatic levitation testing to successfully predict the influence of EML stirring on the incubation time between the two recalescence events.
9:50 AM Break
10:10 AM
Relating Cooling Rates in Superheated Liquid and during Solidification: Peace Muusha1; Douglas Matson1; Matthias Kolbe2; 1Tufts University; 2DLR-Koln
Selection of the appropriate cooling rate during solidification is an important control parameter for tailoring the microstructure to obtain desired final properties. The superheated liquid cooling rate is relatively easy to set, however this then also sets the cooling rate once solid begins to form. A model is developed relating these two cooling rates as a function of melt thermophysical properties and it is validated using containerless space processing techniques in the ESA ISS-EML facility.
10:30 AM
Effects of Oxygen on the Surface Tension of Liquid Inconel 718: Michael Sansoucie1; Elizabeth Hodges2; Robert Hyers2; 1NASA Marshall Space Flight Center; 2University of Massachusetts
Surface tension is an important property for heat and mass transfer modeling of several industrial processes, including casting of jet engine turbine blades, welding of nuclear reactor containers, and crystal growth of semiconductors. The surface tension of molten metals is affected by even a small amount of adsorption of surface active elements such as oxygen. The NASA Marshall Space Flight Center’s electrostatic levitation (ESL) laboratory has a system that allows the oxygen partial pressure within the levitation chamber to be measured and controlled over a wide range. The surface tension of molten Inconel 718 was measured at several oxygen partial pressures using the oscillating drop method, and the results will be presented.
10:50 AM
Experimental and Numerical Investigation of Dynamic Behavior of an Oscillating High-density Drop Processed using Electrostatic Levitation Furnace Aboard the International Space Station: Ali Rabeh1; Makrand Khanwale2; Masahito Watanabe3; Robert Hyers4; Michael SanSoucie5; Jonghyun Lee1; Baskar Ganapathysubramanian1; 1Iowa State University; 2Stanford University; 3Gakushuin University; 4University of Massachusetts Amherst; 5NASA Marshall Space Flight Center
The surface tension of molten oxides and the interfacial phenomena between molten iron and motel oxides are being studied using the Electrostatic Levitation Furnace (ELF) aboard the International Space Station. Once a levitated drop of 2-3 mm in diameter is excited by resonance, the drop dampens freely. During this free oscillation damping, the amplitude shows an exponential decay. An oscillation curve is fitted with the Legendre polynomials and the damping constant is extracted. The surface tension is determined using the extracted damping constant by the Rayleigh equation. To design and interpret the results from such space experiments, a numerical model has been developed using a phase field approach. A projection-based discretization and adaptive mesh were used to reproduce the ELF experiments by solving the Navier-Stokes and the Cahn-Hillard equations. The numerically predicted surface tension showed good agreement with that from the ELF experiments.