Shape memory alloy makes moves for micro-robots

Shape memory alloys have the ability to “remember” their shape, meaning they can be deformed and then returned to their previous form when heated.

However, existing shape memory alloys are typically only able to change from one shape to another, or in response to one particular temperature change.

By developing functionally graded shape memory alloys, a team of UK researchers are hoping to modify these properties at different points in the material. In this way the material could change its shape in response to different temperatures at various points on the device, for example.

This would allow much more complex and controllable micro-robots to be built, according to Professor Duncan Hand at Heriot-Watt University, who is developing the alloys in an EPSRC-funded project alongside his colleague Professor Bob Reuben.

To produce the tailored materials, the researchers are developing a new technique known as functionally graded Laser Induced Forward Transfer (FG-LIFT).

Thin films of metal, such as nickel, titanium or copper, layered on a transparent polymer, are deposited onto a substrate using a pulse laser, said Hand.