By G.P. Thomas
New research into how materials act in space could lead to improvements in the design of everyday objects.
The research is part of an on-going collaborative effort between NASA and other high profile institutions including the French Space Agency, CNES, Northeastern University, Iowa State University, and Aix-Marseille University in France.
The latest findings have been published in Physical Review Letters, and concern the process of directional solidification aboard the International Space Station.
The research was conducted on the International Space Station. Image credit: nasa.gov
These finding could have huge implications for structural alloys on Earth, which are produced via the process of solidification.
Structural alloys are an integral part of everyday life, and are implemented in products from aircraft wings to gas pipelines.
Solidification is an intuitive process, though perhaps not one that we think about very often in our day-to-day lives. It is simply the phase transition from a liquid to a solid, most commonly seen as liquid water turns to ice. However, it is also an extremely important method of constructing complex objects for industrial use.
Prof. Alain Karma, a collaborator in this study from Northeastern University, explains the process further:
"Solidification happens all around us, either naturally, as during the crystallization of familiar snow-flakes in the atmosphere, or in technological processes used to fabricate a host of materials, from the large silicon crystals used for solar panels to the making of almost any man-made object or structure that needs to withstand large forces, like a turbine blade."
However, the solidification process of structural alloys generates morphological instabilities on a microscopic level, as the solid-liquid interface changes from being planar to a more complex cellular structure.
But removing gravity from the equation leads to interesting results, as Prof. Karma recently explained:
"Without gravity, there is no buoyancy force to mix the atomic constituents in the melt by fluid flow."
"As a result, solidification creates unique, more organized, structures that cannot be observed on earth”.
Lighter and Stronger
The insights provided by this research could lead to the development of alloys that are lighter and stronger, which could have major positive implications both economically and environmentally.
These insights add yet another chapter to the extremely diverse range of microgravity
research conducted by NASA.
For over 25 years, NASA has been performing experiments to determine the effect of gravity on chemical, biological and physical systems. With both ground-based and space flight experiments, this research is conducted in a state of minimal gravity, in order to better understand how materials act without the interference of gravity.
There are certain major advantages to these tests. For example, experiments can be conducted over long periods of time, meaning the types and number of materials that can be processed to full term is greatly increased. This is beneficial for research areas such as crystal growth. Furthermore, on the space station, a series of experiments can be conducted uninterrupted, without the need keep flying back and forth.
Further microgravity experiments relate to solidification of other metal alloys, semiconductor crystal growth, and graphene.
Japan Aerospace Exploration Agency astronaut Satoshi Furukawa, pictured near the Microgravity Science Glovebox (MSG) located in the Destiny laboratory of the International Space Station. Image credit: NASA.gov
Original Source: Northeastern University College of Science
More information can be found at: Microgravity research Center - NASA