VISCOUS LIQUID FOAM - BULK METALLIC GLASS (FOAM)
Research Area: Materials Science
Expedition(s): 9
Principal Investigator(s): ● William L. Johnson, PhD, California Institute of Technology,
Pasadena, Calif, United States
RESEARCH OBJECTIVES
The Viscous Liquid Foam - Bulk Metallic Glass (Foam) investigation tests and produces hardened
foam from bulk metallic glass. The absence of gravity facilitates the creation of a more uniform
metallic glass foam, a material with an extremely high strength to weight ratio. Developing
lighter and stronger materials can lead to a more durable spacecraft that will require less
propellant to travel long distances.
EARTH BENEFITS
Bulk metallic glasses are extremely
strong materials (2-3 times
stronger than conventional
metals) that, when molten, are
viscous enough to make well-
constructed solid foam. While bulk
metallic glass is strong, it is also
brittle. A bulk metallic glass foam
is very resilient, however, much
like spongy human bone. Solid
foams are the best materials to
make large, stiff structures due to
their high strength to mass ratio.
Foaming also considerably
increases a material's ability to act as a temperature insulator. Foam can be difficult to study on
Earth because gravity can interfere with bubble formation, causing the bubbles to rise and the
liquid to sink. This is especially true when conventional metal liquid (like aluminum or titanium)
is foamed. A better understanding of foaming will help investigators improve a variety of
materials used in everything from medical supplies to industrial processing, sports equipment
and military vehicles.
SPACE BENEFITS
Hardened bulk metallic glass foam may be very useful as a material for building future
spacecraft for long-term spaceflight. The foams can also be used to build permanent structures
on the moon or Mars. Buildings and spacecraft fuselages made from bulk metallic glass foams
can be extremely tough and light at the same time, thereby reducing costs while increasing the
protection they provide to explorers.
ISS009E14583 – Foam investigation setup in the Maintenance
Work Area on the International Space Station during Expedition 9.