US investigations in Materials Science aboard the International Space Station

Paper number

IAC-08.A2.6.A5

Author

Dr. Frank Szofran, NASA Marshall Space Flight Center, United States

Year

2008

Abstract

The International Space Station (ISS) provides a platform for long duration low gravity materials experiments.    Planned campaigns will investigate issues of continuing importance in materials science, in particular the prediction and control of microstructure and determining factors behind nucleation and growth.  Six joint-ESA investigations are currently planned.

The Materials Science Research Rack (MSRR) planned for launch in May 2009 will support a series of joint NASA-ESA experiments in ESA’s Materials Science Laboratory (MSL) incorporating modular furnace inserts.   The first insert will be a Low Gradient Furnace (LGF) and will be used for the experimental programs Microstructure Formation in Castings of Technical Alloys under Diffusive and Magnetically-Controlled Convective Conditions (MICAST), Columnar-Equiaxed Transition in Solidification Processing (CETSOL), Ge-Si Crystallisation, and Cd-Te Crystallisation.  The second insert, the Solidification and Quench Furnace (SQF), will be used for examining interrupted solidification.   MICAST and CETSOL probe the important issues of pattern formation and will obtain benchmark data under idealized low gravity conditions.   MICAST specifically will directionally solidify technical alloys in the aluminium-silicon family in order to test the effects of heat and mass transfer under diffusive conditions, and through an examination of the resulting microstructure and segregation.  The CETSOL experiments are designed to determine the parametric conditions that control the transition of columnar to equiaxed grain structure within castings.    In the Ge-Si experiment, the intent is to achieve a low density of defects by solidifying in a “detached” mode, in which the solidifying material does not wet the crucible walls.  The Cd-Te crystallization will use both Bridgman and vapor transport to optimize conditions for producing homogeneous alloys of CdTe with low defect densities.  The MSL provides a rotating magnetic field capability which can be tuned to control residual convection produced by low frequency g-jitter components present on ISS.  
 
Another investigation is planned for the May 2009 launch, namely the CNES DECLIC apparatus, which will have a Directional Solidification Insert (DSI).    The sample in this case will be a transparent plastic alloy with a low melting point.   The sample can be solidified and re-melted many times, while the interface is examined with optical techniques.   This provides excellent opportunities for examining the effects of experimental parameters and boundary conditions on pattern formation during alloy formation.  

US investigators will also participate in two containerless processing experiments within the Electromagnetic Levitator (EML) which will be launched in the 2011 time frame.  Studies will be made of undercooling of liquids, their subsequent recalescence, nucleation phenomena and metastable solidification.    The investigators will also make use of the quiescent conditions achievable in low gravity to measure thermophysical properties.

Abstract document

IAC-08.A2.6.A5.pdf

Manuscript document

IAC-08.A2.6.A5.pdf (🔒 authorized access only).

To get the manuscript, please contact IAF Secretariat.