RESULTS
The experiment was designed to
test the hypothesis that
amorphous metals exhibit foam-
making qualities on the ground
that mimic metallic foam textures
made in microgravity conditions.
The amorphous metals, when
softened or melted, have a super-
cooled state that has a very high
viscosity—ideal conditions for
foam processing. Foam made
from a Pd 40 Ni 40 P 20 glass-forming
metallic liquid, was made both on
the ground and aboard the
International Space Station (ISS).
Pellets of the material that contained 1-atmosphere bubbles, were sealed in ampoules. The
ampoules were made to thread into a soldering iron tip for heating aboard the ISS. The samples
were heated at 360°C for 5 minutes, enabling foam creation, then allowed to cool. The ground
samples contained textures that were similar to those produced in microgravity—equally
distributed bubbles dominated by surface tension forces; the bubbles did not experience
sedimentation (floating). These types of foams have great potential for future exploration
applications because of their great strength and light weight. In particular, such foams may
make very effective shields against micrometeorite and orbital debris strikes.
PUBLICATION(S)
Hofmann DC, Roberts SN. Microgravity metal processing: From undercooled liquids to bulk
metallic glasses. npj Microgravity. May 27, 2015;1:15003. doi: 10.1038/npjmgrav.2015.3.
Veazey C, Demetriou MD, Schroers J, et al. Foaming of amorphous metals approaches the limit
of microgravity foaming. Journal of Advanced Materials. 2008;40(1):7-11.
This investigation is complete and all results are published.
ISS009E14593 – Close up image of the Foam investigation on the
International Space Station, Expedition 9.