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Information × Registration Number 0215U001205, 0112U002638 , R & D reports Title Physical-mechanical properties of nanocrystalline, ultrafine-grained and amorphous solids under conditions of low and extremely low temperatures popup.stage_title Head Pal-Val Pavlo Pavlovych, Registration Date 03-02-2015 Organization B.I.Verkin Institute for Low Temperature Physics and Engineering of National Academy of Sciences of Ukraine popup.description2 This work is devoted to investigation of new peculiarities of inelastic deformation of modern materials and development of theoretical models of physical processes which govern inelastic deformation in extreme conditions of low and ultralow temperatures. It is established that irrespective of a technology of obtaining nanostructured (NS) metals, in the temperature interval 0,5 - 340 K, dislocation mechanisms of plastic flow, internal friction and the microhardness remain dominating but complicated by influence of a significant amount of deformation defects on dislocation mobility. It is shown, that fragmentation of grains and increase of the dislocation density stimulate a development of the low-temperature jump-like plastic deformation of metals. Using methods of acoustic spectroscopy, it was experimentally registered for the first time existence of "a glass-like phase" in the NS metals obtained by the low-temperature methods of severe plastic deformation. It was revealed huge (up to 50 %) reduction in Young's modulus as a resulat of significant transformations of crystallographic texture in annealed samples of copper. Boundaries of the thermal and structural stability of NS titan prepared by a cryomechanical method of grain fragmentation were established. It has been shown, that the NS state was kept when increasing temperature up to 550 K and was homogeneous enough. Homogeneity of the structure, high mechanical characteristics make given material perspective for wide practical application. General postulates of the atomistic and continual mechanics of the 2D crystals are developed. On this basis, the system of the base equations is derived which determine plastic and elastic deformations of the 2D crystal, caused by defects of the dislocation and crowdion type. By methods of molecular dynamics, it is performed modelling of defects in the 2D HCP crystals and eigenvalues of energies of the dislocation and crowdion as well as the sizes of their cores are estimated. Product Description popup.authors Іванченко Л.Г. Ісаєв М.В. Абраімов В.В. Алексенко Є.М. Безкорсий О.П. Брауде І.С. Ватажук О.М. Волобуєв Ф.І. Гамуля Г.Д. Гейдаров В.Г. Григорова Т.В. Забродін П.А. Заріцький І.П. Кіслов О.М. Казаров Ю.Г. Кириченко Г.І. Лебідь В.О. Лотоцька В.О. Лубенець С.В. Москаленко В.А. Нацик В.Д. Паль-Валь Л.М. Паль-Валь П.П. Плотнікова Ю.М. Подольський О.В. Псарук І.А. Русакова Г.В. Сальтевський Г.І. Семеренко Ю.О. Смірнов А.Р. Смірнов С.М. Смолянець Р.В. Табачнікова О.Д. Фоменко В.С. Фоменко Л.С. Церковний О.І. Шляхов В.В. Шумілін С.Е. Яковенко Л.Ф. popup.nrat_date 2020-04-02 Close