biology and biotechnology

MATERIALS SCIENCE LABORATORY - COLUMNAR-TO-EQUIAXED TRANSITION IN

SOLIDIFICATION PROCESSING AND MICROSTRUCTURE FORMATION IN CASTING OF TECHNICAL

ALLOYS UNDER DIFFUSIVE AND MAGNETICALLY CONTROLLED CONVECTIVE CONDITIONS (MSL-

CETSOL AND MICAST), TWO INVESTIGATIONS
Research Area: Materials Science
Expedition(s): 21-24, 27-ongoing
Principal Investigator(s): ● David Poirier, Sc.D., University of Arizona, Tucson, Arizona
● Gerhard Zimmermann, PhD, ACCESS e.V., Aachen, Germany,
Lorenz Ratke, Institute for Space Simulation, Cologne,
Germany

RESEARCH OBJECTIVES
MSL-CETSOL and MICAST are 2 investigations that support research into metallurgical
solidification, semiconductor crystal growth (Bridgman and zone melting), and measurement of
thermo-physical properties of materials. This is a cooperative investigation with the European
Space Agency and NASA for accommodation and operation aboard the International Space
Station (ISS).

EARTH BENEFITS
These linked experiments aim to improve our understanding of the solidification processes of
metallic alloys. As the mechanical properties, and therefore potential Earth-based applications,
are directly related to solidification conditions, it is crucial to validate the predictions of
numerical models that describe solidification processes. Additionally, this research improves
knowledge of casting processes, so that future tailored metallic alloys can be created for
several applications of our daily life.

SPACE BENEFITS

The MSL-CETSOL and MICAST

investigations will provide a

unique insight into microgravity

solidification processes of cast

alloys under well controlled

conditions.

RESULTS

When a molten metal or alloy

cools and crystallizes, the resulting

solid generally has 2 competing

types of grain structures. At first,

fast cooling of the melt normally

forms columns of long branching

grains growing inward from the

side walls. Then as internal heat is

Microstructure and grain structure in longitudinal cross-sections of

flight samples showing columnar growth (top) and transition to

equiaxed grain growth (bottom). ACCESS Technology, Aachen,

Germany image.