A new scheme of composite functional material based on an alloy exhibiting a shape-memory effect (SME) is proposed. The scheme provides for a giant reversible bending deformation with the use of only...

New scheme of a functional composite material based on a shape memory alloy has been developed and experimentally tested. The proposed scheme ensures a giant reversible bending deformaion using only...

An enhanced scheme of a functional composite material has been proposed and tested in the model experiments. The composite consists of an element with shape memory effect (SME) in the form of ribbon, film or plate connected rigidly to an element of an elastic material. The novel feature in this scheme is that an SME element should be preliminary given the uniaxial pseudoplastic tensile straining. This operation promotes the martensite twins formation along the stretching axis and results in the maximal longitudinal deformation of SME element. Such scheme provides a well-controlled high reversible bending deformation of the composite, though only one-way SME of the material is used. It can be applied to the most conventional shape memory materials, such as polymers, ferromagnetic and non ferromagnetic alloys. The scheme is experimentally tested on the composites made by applying an elastic layer on the preliminary pseudoplastically stretched melt-spun ribbons of the Ti50Ni25Cu25 alloy (see video on the web: www.smwsm.org/ll/composites.html). The elastic layer was applied by three different techniques: gluing, electroplating and focused ion beam assisted chemical vapor deposition (FIB/CVD). Fatigue experiments showed that the composite made by electroplating of Ni layer demonstrates fairly stable actuation for at least 2000 cycles. FIB/CVD allowed a preparing of a composite actuator with the dimensions of about 25×1×1μm. The scheme is promising for the applications in the fields of MEMS and NEMS, microfluidics and biomedical technologies

Samples of thermally controlled shape memory alloy (SMA) composite nanotweezers based on bilayered structures Ti ₂ NiCu/Pt with dimensions (0.8-30)×(0.1-10)×(0.07-2)μm have been developed. Each of these composites could be used to create the smallest miniature devices to date for micro- and nanomechanics, fluidics, electronics, medicine and S&A technologies. It was found that the reversible deformation of the composite created by FIB milling is greater than 1 % when the thickness of SMA layer varies from 1μm to 100 nm. The new system of nanotweezers actuation by application of electric current is proposed and theoretical modeling of the new system was done. Experimental tests of the new control system of nanotweezers have been performed. The actuation of nanotweezers in a full cycle (open - close - open) was demonstrated with frequency as high as 1 kHz. Further increase of frequency causes the decrease of bending deformation of nanotweezers. Nevertheless, even at 100 kHz self-oscillation have been detected directly under constant voltage apply. We have demonstrated 3D manipulation of 30 nm single carbon nanotube, stack of graphene layers, viskers of different materials and even mosquito's hair.

The shape memory effect (SME) in alloys with a thermoelastic martensite transition opens unique opportunities for the creation of miniature mechanical devices. The SME has been studied in layered composite microstructures consisting of a Ti₂NiCu alloy and platinum. It occurs upon a decrease in the active layer thickness at least to 80 nm. Some physical and technological restrictions on the minimum size of a material with SME are discussed.