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Information × Registration Number 0224U001691, 0121U108516 , R & D reports Title Physico-mechanical properties of modern constructive and functional materials at low and ultralow temperatures popup.stage_title Head Pal-Val Pavel P., Доктор фізико-математичних наук Registration Date 26-01-2024 Organization B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine popup.description2 In the temperature range of 0.5 – 350 K, the mechanical and acoustic properties of a number of the newest promising for practical application materials have been thoroughly investigated. The purpose of the research was to establish physical mechanisms that control the physical and mechanical properties of materials at low and ultra-low temperatures. The authors used a complex of modern experimental techniques: methods of active deformation; microindentation; acoustic spectroscopy techniques; X-ray, electron microscopic and optical control of the sample structure; the electron backscatter diffraction (EBSD) method, modern methods of solid state theoretical physics. As a result, a number of world-class results were obtained, which will contribute to the development of fundamental ideas about the mechanisms of plasticity and strength of materials at low and ultra-low temperatures. In particular, a molecular-kinetic model of highly elastic deformation of amorphous polymers was proposed for the first time. Within this model, an exact solution of the nonlinear rheological equation was obtained, which describes the kinetics of forced highly elastic deformation of amorphous polymers under conditions of moderate and deep cooling, a three-stage tensile diagrams of samples were predicted, and a molecular-kinetic interpretation of each stage was proposed. It is established that plasticity of the high-entropy Fe50Mn30Co10Cr10 alloy in the temperature range of 0.5–300 K is induced by phase transformations between the fcc and hcp phases (TRIP mechanism). For the first time, a substantiated strategy for solving the dilemma "high strength - low plasticity" for high-strength nanocrystalline hcp metals is proposed, which consists in creating a heterogeneous grain structure with a certain distribution of grain size.   Product Description popup.authors popup.nrat_date 2024-01-26 Close