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)

Laminated Amorphous-Crystalline Rapid Quenched Ribbons of Ti50Ni25Cu25 alloy with Two-Wae Shape Memory Effect

Alloys with shape memory effect are promising materials for the creation actuators of various devices. For the miniaturization of devices it becomes relevant to obtain thin-dimensional materials with the effect of two-way shape memory (TWSME). This work is devoted to the study of the properties of rapid-quenched amorphous-crystalline thin ribbons from the TiNi–TiCu alloy system, possessing TWSME.Сплавы, обладающие эффектом памяти формы, являются перспективными материалами для создания приводов различных устройств. Для миниатюризации таких устройств, создания микро- и, возможно, наноустройств является актуальным получение тонкомерных материалов с эффектом обратимой памяти формы (ЭОПФ). Данная работа посвящена исследованию свойств быстрозакаленных аморфно-кристаллических тонких лент из сплава системы TiNi–TiCu, обладающих ЭОПФ.Работа выполнена по гранту при финансовой поддержке РНФ, проект № 19-72-00145

Martensitic transformation in amorphous-crystalline Ti-Ni-Cu and Ti-Hf-Ni-Cu thin ribbons

Martensitic transformations and strain variation in amorphous-crystalline thin ribbons of Ti50Ni25Cu25, Ti40.7Hf9.5Ni44.8Cu5 and Ti40.7Hf9.5Ni39.8Cu10 alloys were investigated. The amorphous-crystalline state in the samples was produced by an interruption of the isothermal crystallization in DSC apparatus. The volume fraction of the crystalline phase Vcryst in the samples was varied from 10 to 100%. Transformation temperatures in amorphous-crystalline thin ribbons of Ti50Ni25Cu25 alloy depended only slightly on the crystalline volume fraction. On the contrary, the strong dependence of the martensitic transformation temperatures on the volume of crystalline phase was obtained in Ti40.7Hf9.5Ni44.8Cu5 and Ti40.7Hf9.5Ni39.8Cu10 alloys. Moreover, it was found that the intervals of the direct transformation are extremely narrow, whereas the intervals of the reverse transformation are unusually wide. As the crystalline volume fraction rises, both the direct transformation interval and the reverse one decrease, and the transformation temperatures increase. It was shown that increase of the Cu-content in Ti40.7Hf9.5Ni49.8 -xCux (x = 5, 10%) alloys results in decrease of the transformation temperatures, of the temperature interval of the reverse transformation on heating and of the hysteresis, while the temperature interval of the direct transformation on cooling widen