Creating a solid foam by introducing gases into a mixture of molten glass and molten metal and allowing the mixture to cool without gravity separating the components might create a more uniform structural material (metal foam) with the strength of steel and the corrosion resistance of glass. 1
Experiments have been performed in space, but difficult to find applications in which bulk metallic glasses or solid foam can offer sufficiently high improvements in performance to justify the cost.5
- Moon or Mars habitats (space structures).
- Shielding against micrometeorites and space debris impacts (debris shields).3
- Mirrors, compliant mechanisms, cellular structures and gears.
- Hinges, sliders, frames, display frames, miniature camera case, phone cases, golf clubs, surgical tools, SIM eject tool for iPhone2 4
Why & Solution
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. Metal foam is metal alloy that, when cooled from a liquid to a solid at high cooling rates, solidifies without crystallizing. Because the effects of buoyancy are minimized in space, more uniform foam structures with unique properties can be produced.3
"Because you don't have stratification as a result of density differences — heavy stuff doesn't sink to the bottom, and light stuff [doesn't] go up to the top — you can create alloys that are a homogenous blend of metals or minerals that would not ordinarily be able to be manufactured in as large a size on the ground," Harper said. "And, in fact, you may have some unique ones that wouldn't produce an alloy under any conditions on the ground." 2
Having a material that can be packaged into a small launch volume and then be deployed on-orbit, to either fill a mold or in free expansion, while still retaining high-strength and excellent energy-absorbing capacity, is a major advancement for space manufacturing. 6
Earthly Solution Risk
Numerous potential applications on Earth, but unknown whether making in space is practical.