Researchers have created a liquid metal lattice made from Field’s alloy, a mix of bismuth, indium, and tin. The alloy becomes liquid at the relatively low melting point of 62 °C (144 °F).
Field’s alloy is currently used as a liquid-metal coolant in nuclear engineering, among other applications. The researchers combined the metal lattice material with a rubber shell through a hybrid manufacturing process that integrates 3D printing, vacuum casting, and conformal coating (used on electronic circuitry to protect against moisture, dust, chemicals and temperature extremes). The shell skeleton controls the overall shape and integrity, so the liquid metal itself can be confined in the channels.
The team made a series of prototypes that regain their shapes after being heated to the melting point including mesh antennas, honeycombs, soccer balls, and a hand that slowly opens as the metal lattice melts. When the liquid metal is in a solid state, it is very safe and strong; it absorbs a lot of energy when crushed. Then, after some heating and cooling, it returns to its original shape and can be reused.
Satellite designers could pack an antenna into a small package and then unfold it when in orbit. A spacecraft, for example, may crash if it lands on the Moon or Mars with some kind of impact. Normally, aluminum or steel are used to produce the cushion structures but after landing on the Moon, the metal absorbs the energy and deforms so it can only be used once. Using Field’s alloy, it can be crashed into like other metals but then heated up later to recover its shape, enabling multiple uses.
The team is exploring how to build on this metal lattice research including different structure types and improved coating materials.