This article studies the deformation resistance of high-temperature superconducting (HTSC) tapes for various parameters of deformation. The four-contact method has been used to measure the critical current in specimens deformed on indenters with diameters of 5–20 mm by tensile forces up to 200 N. The damage to the superconducting layer and local superconducting properties of mechanically impacted specimens have been investigated using scanning electron microscopy and scanning Hall magnetometry.

Insect pest control requires fundamental knowledge of their physiology and behavioral responses. However, due to the small size of insects in general and their sensory organs (sensilla), in particular, the study of the physiology of insect sensory systems has until recently been limited by insufficient accuracy and selectivity of experimental mechanical action. To eliminate this gap in the study of insects nervous system, a microrobotic technology is proposed based on a micromechanical device - microtweezers based on a layered structural composite of $\text{Ti}_{50} \text{Ni}_{25} \text{Cu}_{25}$ alloy with a shape memory effect (SME), combined with a temperature control system and a three-coordinate piezoelectric micropositioner. Microtweezers with SME selectively capture the smallest sensilla of the studied insects, enabling their precise mechanical stimulation with simultaneous recording of physiological responses generated by sensilla by methods of electric impulse derivation in the nerve centers of the insect.

Insect pest control requires fundamental knowledge of their physiology and behavioral responses. However, due to the small size of insects, in general, and their sensory formations (sensilla), in particular, the study of the physiology of insect sensory systems has until recently been limited by insufficient accuracy and selectivity of experimental mechanical action. To eliminate this gap in the study of insects, a physical technology is proposed based on a micromechanical device - microtweezers based on a layered structural composite of Ti50Ni25Cu25 alloy with a shape memory effect (SME), combined with a temperature control system and a three-coordinate piezoelectric micropositioner. Microtweezers with SME selectively capture the smallest sensilla of the studied insects, enabling their precise mechanical stimulation with simultaneous recording of physiological responses generated by sensilla using methods of impulse derivation in the nerve centers of the insect.

Аморфно-кристаллический сплав квазибинарной системы TiNi—TiCu с содержанием меди 25 ат.% изготовлен методом быстрой закалки из жидкого состояния в виде тонких лент. Полностью аморфное состояние получали с помощью электрохимической полировки. Показано, что кристаллическая структура, полученная методом высокоскоростной электроимпульсной термообработки, значительно отличается от таковой, полученной методом изотермической термообработки. Кристаллизация исходной ленты сопровождается формированием столбчатых кристаллов от обеих поверхностей ленты и крупных кристаллов линзовидной формы в объеме ленты, при этом структура столбчатых кристаллов повторяет морфологию и текстурированность исходного кристаллического слоя. Уменьшение времени электроимпульсного воздействия до 1 мс приводит к росту доли столбчатых кристаллов, увеличению их высоты и уменьшению ширины. После кристаллизации аморфной ленты структура столбчатых кристаллов от обеих поверхностей имеет одинаковую кристаллографическую ориентацию.

Amorphous-crystalline alloy of the TiNi–TiCu quasi-binary system with 25 at.% copper content is prepared in the form of thin ribbons by rapid quenching from a liquid state. Completely amorphous ribbons are obtained using electrochemical polishing. It is shown that the crystal structure prepared by high-speed electropulsing heat treatment differ significantly from that prepared by isothermal heat treatment. The initial ribbon crystallizes as column-like crystals growing from both surfaces of the ribbon and as large lens-like crystals in the volume of the ribbon. The structure of column-like crystals reproduces the morphology and texture of the original crystalline layer. Reducing the electropulsing time to 1 ms increases the fraction of column-like crystals while their height increases and the width decreases. After the amorphous ribbon is crystallized, the structures of column-like crystals on both surfaces have similar crystallographic orientations.

Amorphous ribbons from a rapidly quenched alloy of the TiNi–TiCu quasi-binary system with copper content of 30 at % are crystallized via electric pulse treatment with variable durations of impact in the range of 1 to 100 ms at external tensile stress of up to 250 MPa. It is shown that the formed bimorph structure of columnar and coarse crystals is characterized by considerable differences when compared to a rapidly quenched alloy with 25 at % copper. An increase in tensile stress does not affect the phase composition or microstructure of the alloy, but it does lower the critical temperatures of martensitic transformation.

Thin materials exhibiting the shape memory effect, with a narrow temperature hysteresis, are required to create miniature and high-speed devices. Quasi-binary intermetallic TiNi-TiCu alloys with high copper contents (more than 10 at %) demonstrate the reversible martensitic transformation with a small (4-6 K) hysteresis. Alloys of the TiNi–TiCu system with a copper content of 30–40 at.% were fabricated in an amorphous state by the planar flow casting technique at a melt cooling rate of 10 6 K/s in the form of ribbons 30–50 μm thick. The alloy samples were subjected to dynamic crystallization using a single electric current pulse with duration of 5 ms. X-ray diffraction studies revealed almost fully martensitic state of the alloys with B19 structure at room temperature. TEM examination showed their structure to contain typical B19-martensite plates with a mean size of 20–80 nm. At the same time, the alloys exhibit a one-stage phase martensitic transformation B2↔B19 in the temperature range of (55÷75)°C, as well as pronounced shape memory effect, whose properties are largely determined by the structural parameters of the alloys.

Amorphous alloys of the TiNi - TiCu system with a copper content of 25 to 40 at.% were prepared by planar flow casting at a melt cooling rate of 106 K/s. Crystallization of the alloys was carried out by isothermal annealing and by action of single electric pulse with a duration of 5 ms. Shape memory behavior and structure of the alloys was investigated by means of bending tests and X-ray phase analysis. It was found that increasing the copper content to above 30 at.% considerably reduces the plasticity and shape memory effect of the alloys. However, abrupt decreasing the annealing duration significantly improves the shape memory performance due to prevention of the formation of brittle Ti-Cu phases in the alloys structure.

The work deals with application of laser radiation for creation of metamaterial – layered structural composite based on rapidly quenched TiNiCu thin ribbon. Structural properties of the composite were examined by transmission and scanning electron microscopy. Considerable two-way shape memory effect was achieved and studied.

The rapidly quenched alloys of the quasibinary intermetallic TiNi-TiCu system with a high copper content (more than 25 at.%) are of great interest as shape memory materials due to the possibility of a significant decrease in the temperature and deformation hysteresis in comparison with the binary TiNi alloy. To obtain alloys with a copper content of 25 to 40 at.%, the planar flow casting technique was used. The alloys were fabricated at a melt cooling rate of about 10 6 K/s in the form of ribbons 30-50 μm thick and wide in the range from 7 to 20 mm. The study of the structure of the alloys was carried out using X-ray diffraction analysis, scanning and transmission electron microscopy. It was shown that from the ribbon side, contacting the quenching wheel, all alloys are amorphous, while on the non-contact side of the ribbons of alloys with 25 and 30 at.% Cu, a thin surface crystalline layer with a B2 structure is observed. Using energy dispersive X-ray spectroscopy, it was found that the content of the alloy components in the amorphous and crystalline phases coincides.

The effect of martensitic deformation on the two-way shape-memory effect (SME) of quasi-binary high-copper TiNi–TiCu alloys (with 25–40 at % Cu) is studied. The alloys are prepared by rapid quenching from the melt in an amorphous state in the form of ribbons 30–50 μm in thickness. The alloys crystallize during isothermal annealing, the time of which is varied from 100 to 300 s, and during a single current pulse 10 ms in duration. The relatively low bending strains (1.5–3%) are shown to cause two-way SME in TiNiCu alloys; as the strain of martensite increases, the reversible strain in the martensitic transformation range increases markedly. An increase in the copper content is found to cause a substantial decrease in the value of two-way SME, which is related to the formation of the brittle TiCu phase. At the same time, a decrease in the heat treatment time causes an increase in the reversible strain, which reaches the maximum value (2.35%) for the alloy with 25 at % Cu subjected to high-rate electric pulse treatment.

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.

Using an original approach, a pronounced two-way shape memory effect is created for the first time in rapidly quenched alloys of the quasibinary TiNi–TiCu system with copper contents of up to 38 at %. The technique includes the combined effect of the dynamic crystallization of the amorphous state by application of a single pulse of electric current of 10 ms duration and pulsed laser radiation (λ = 248 nm, τ = 20 ns). The obtained composite structure materials can be used to create different micromechanical devices, especially microswitches and microtweezers for gripping micro-objects.

The work deals with the study of the influence of combined action of thermomechanical and laser treatments of rapidly quenched TiNiCu thin ribbons on the properties of two-way shape memory effect. It was shown that increasing of the energy density of the laser radiation and the external mechanical stress leads to growth of the reversible strain of the received amorphous-crystalline composite in the interval of martensitic transformation.

The effect of pulsed laser radiation (lambda = 248 nm, tau = 20 ns) on structural properties and shape memory behavior of the rapidly quenched Ti50Ni25Cu25 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.