Development of Two-Way Shape Memory Material on the Basis of Amorphous-Crystalline TiNiCu Melt-Spun Ribbons for Micromechanical Applications

Abstract

The paper deals with the development of a structural composite material exhibiting twoway shape memory effect. A Ti-Ni-Cu alloy was produced by the melt spinning technique at different cooling rates in the form of a ribbon with a thickness of approximately 40 µm. Layered amorphous-crystalline structure of the ribbon was obtained by varying the alloy composition and the cooling rate and by modification of the alloy structure with the external extreme action (pulsed laser emission and periodical discharge in the liquid flow). The relation between thicknesses of the amorphous and crystalline layers was changed by the variation of parameters of the melt spinning and the external actions as well as with the aid of electrochemical polishing. The samples were characterized by means of inverted metallographic and scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, energy dispersive X-ray analysis and microhardness measurements. It has been shown that the layered amorphous-crystalline composite material demonstrates clearly defined two-way shape memory behavior without any additional thermomechanical treatments and can be used to create micromechanical devices with a higher level of functional properties.