Application of Laser Radiation for Fabrication of Micromechanical Actuator Based on Two-Way Shape Memory Effect

The work deals with production and research of experimental samples of micromechanical actuator based on the rapidly quenched TiNiCu alloy, in which a two-way shape memory effect is formed as result of impact of the laser radiation. By the technique of focused ion beams an element with thickness of 5 microns, width of 7 microns and 100 microns in length was obtained, bending reversibly to 2.5 microns in the heating-cooling cycle. Keywords: shape-memory alloy, thin ribbon, two-way shape memory effect, laser treatment, micromechanical actuato

RESEARCH OF RAPIDLY QUENCHED RIBBONS OF TINICU ALLOYS WITH HIGH COPPER CONTENT

Amorphous alloys of the TiNi–TiCu system with a copper content of 25 to 40 at. % were obtained by melt spinning technique in the form of 30–50 µm thick ribbons. It is shown that, compared to isothermal annealing, high.speed electropulse heat treatment leads to a dramatic improvement in the ductility of alloys and characteristics of shape memory effects.Аморфные сплавы системы TiNi–TiCu с содержанием меди от 25 до 40 ат. % получены методом спиннингования расплава в виде лент толщиной 30–50 мкм. Показано, что по сравнению с изотермическим отжигом высокоскоростная электроимпульсная термообработка приводит к резкому улучшению пластичности сплавов и характеристик эффектов памяти формы.Работа выполнена за счет гранта РНФ (проект № 19-12-00327)

The formation of the two-way shape memory effect in rapidly quenched TiNiCu alloy under laser radiation

The effect of pulsed laser radiation (λ=248 nm, τ=20 ns) on structural properties and shape memory behavior of the rapidly quenched Ti$_{50}$Ni$_{25}$Cu$_{25}$ alloy ribbon was studied. The radiation energy density was varied from 2 to 20 mJ mm$^{−2}$. The samples were characterized by means of scanning electron microscopy, x-ray diffraction, microhardness measurements and shape memory bending tests. It was ascertained that the action of the laser radiation leads to the formation of a structural composite material due to amorphization or martensite modification in the surface layer of the ribbon. Two methods are proposed which allow one to generate the pronounced two-way shape memory effect (TWSME) in a local area of the ribbon by using only a single pulse of the laser radiation. With increasing energy density of laser treatment, the magnitude of the reversible angular displacement with realization of the TWSME increases. The developed techniques can be used for the creation of various micromechanical devices