Melt-spun thin ribbons of shape memory TiNiCu alloy for micromechanical applications

The development of micromechanical devices (MEMS and NEMS) on the basis of nanostructured shape memory alloys is reported. A Ti 50 Ni 25 Cu 25 (at. %) alloy fabricated by the melt spinning technique in the form of a ribbon with a thickness around 40 μm and a width about 1.5 mm was chosen as a starting material. Technological parameters were optimized to produce the alloy in an amorphous state. The thickness of the ribbon was reduced to 5-14 μm by means of electrochemical polishing. A nanostructural state of the thin ribbons was obtained via the dynamic crystallization of the amorphous alloy by application of a single electric pulse with duration in the range of 300-900 μs. A microtweezers prototype with a composite cantilever of 0.8 μm thick and 8 μm long was developed and produced on the basis of the obtained nanostructured thin ribbons by means of the focused ion beam technique. Controlled deformation of the micromanipulator was achieved by heating using semiconductor laser radiation in a vacuum chamber of scanning ion-probe microscope.