NiTi thin films are promising actuation materials for micro-electro-mechanical systems (MEMS). Multi-layered, composite or functionally graded NiTi-based films can be made to improve the properties of NiTi films. However, they currently require complex thermo-mechanical training to be actuated, which becomes more difficult as devices approach the micro-scale. As the NiTi bi-layer composite showed two-way shape memory actuation, it is decided to implement this structure to the NiTi-based film.
Bi-layer thin films were deposited using RF magnetron sputtering. For studying the two-way shape memory actuation of the bi-layer films, Shape Memory Testing Device was used. Bi-layer films showed intrinsic shape memory actuation without any complicated thermos-mechanical training process.