J. Phys. IV France 11 (2001) Pr8-571-Pr8-576
Laser annealing of shape memory alloys : A versatile tool for developing smart micro-devicesY. Bellouard1, T. Lehnert2, R. Clavel1, T. Sidler3 and R. Gotthardt2
1 Institut de Systèmes Robotiques, DMT, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
2 Institut de Génie Atomique, DP, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
3 Institut d'Optique Appliquée, DMT, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
From a shape change point of view, the shape memory effect is not intrinsically reversible. Therefore developing Shape Memory Alloys (SMA) actuators, i.e. devices producing a motion, requires a suitable method to bypass this intrinsic property. Since the shape memory effect discovery, different methods, either intrinsic like the "Two-Way Shape Memory Effect" or extrinsic like the use of a biasing element have been investigated. In this paper, a new method based on a local annealing of the material is presented. A laser is used to locally crystallise amorphous thin film or re-crystallise cold-worked sheet of SMA material. For instance, this method allows the development of highly integrated micro-devices made out of one single piece of material. The basic principle, a typical setup and some effects of the laser annealing on the material properties are presented followed by some examples of monolithic micro-devices developed using this concept.
© EDP Sciences 2001