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Термомеханические свойства сплава TiNi после высокоскоростного сжатия
Get PDFГригорьева Виктория Игорьевна. Термомеханические свойства сплава TiNi после высокоскоростного сжатия. Научный руководитель: д. т. н., профессор Разов Александр Игоревич. Направление математика и механика, кафедра теории упругости. В работе исследовали термомеханические свойства сплава TiNi при высокоскоростном сжатии со скоростью около 103с-1 при температурах 20-300oC. Эффекты памяти формы исследовали при термоциклировании через интервал обратимого мартенситного превращения. Приведены зависимости фазового и дислокационного пределов текучести, однократной и обратимой памяти формы от температуры испытания. Количество использованных источников – 18. Библиогр. описание: Григорьева В. И. Термомеханические свойства сплава TiNi после высокоскоростного сжатия: магистерская дис.: защищена 08.06.2017 / Григорьева Виктория Игорьевна. – СПб, 2017. – 30 с. – Библиогр.: с. 28-30.Grigorieva Victoria Igorevna. Thermomechanical properties of TiNi alloy after high strain rate compression. Scientific adviser: Doctor of Technical Science, Professor Razov Alexander Igorevich. Direction of mathematics and mechanics, Chair of the theory of elasticity. The thermomechanical properties of the TiNi alloy were studied in high strain rate compression at a speed of about 103 s-1 at temperatures of 20-300 ° C. The shape memory effects were investigated during thermal cycling through an interval of reversible martensitic transformation. Dependences of the phase and dislocation limits of fluidity, single and reversible shape memory on the test temperature are presented. Number of sources used - 18. Bibliogr. Description: Grigorieva VI Thermomechanical properties of TiNi alloy after high strain rate compression: Master's degree: protected 08.06.2017 / Grigoryeva Viktoria. - St. Petersburg, 2017. - 30 p. - Bibliography: p. 28-30
Superelasticity and compression behavior of porous TiNi alloys produced using Mg spacers
No full textIn the scope of the present study, Ni-rich TiNi (Ti-50.6 at %Ni) foams with porosities in the range 38-59% were produced by space holder technique using spherical magnesium powders as space formers. Single phase porous TiNi alloys produced with spherical pores were subjected to loading-unloading cycles in compression up to 250 MPa stress levels at different temperatures in as-processed and aged conditions. It has been observed that strength, elastic modulus and critical stress for inducing martensite decrease with increasing porosity. Partial superelasticity was observed for all porosity levels at different test temperatures and conditions employed. Irrecoverable strain was found to decrease with pre-straining and with increasing test temperature. Unlike in bulk TiNi alloys a constant stress plateau has not been observed during the compression testing of porous TiNi alloys. Instead linear superelasticity with a quite steep slope allowing 5% applied strain to be recovered after pre-straining or aging was observed. Even at test temperatures higher than austenite finish temperature in as-sintered and aged condition, strain applied could not be recovered fully. due to martensite stabilization resulting from heavy deformation of macro-pore walls and sintering necks. TiNi foams produced with porosities in the range of 38-51% meet the main requirements of biomaterials in terms of mechanical properties for use as bone implant
Influence de la teneur de nickel sur le comportement tribologique et électrochimique de l’alliage TiNi.
Get PDFParmi les matériaux métalliques, les alliages de TiNi sont employés principalement pour des applications biomédicales et/ou dentaires dues à leur meilleure compatibilité mécanique avec les tissus, leur module de Young proche de celui de l’os et une résistance élevée à la corrosion dans les fluides du corps et une bonne biocompatibilité. Pour cette raison, le comportement à la corrosion et à l’usure de l’alliage TiNi avec des teneurs en Ni varie de 40 à 60% en poids, ont été étudiés afin de vérifier l’effet du Ni sur la biocompatibilité de cet alliage pour des applications dentaires
Влияние размера зерна на функционально-механические свойства сплава TiNi с памятью формы
Get PDFРабота посвящена изучению эффектов памяти формы в сплаве TiNi с бимодальной зеренной структурой. Полученные результаты показали, что в зернах с размером 80 нм и менее пластическая деформация подавлена, при этом эффект памяти формы совершенен, а эффект обратимой памяти не наблюдается. Увеличение размера зерна и повышение температуры деформирования способствуют развитию пластической деформации, что уменьшается величину обратимой деформации и стимулирует проявление эффекта обратимой памяти формы.This work is devoted to a study of shape memory effects in TiNi alloy with bimodal grain structure. The results obtained show that plastic deformation is suppressed in grains with a size of 80 nm and less. In this case, perfect shape memory effect is found but the two-way shape memory effect is not observed. An increase in grain size and a rise in deformation temperature assist in activation of plastic strain. This decreases the value of the reversible strain but induces the two-way shape memory effect
Band inversion and topological aspects in a TiNI monolayer
No full textTo achieve a device application of the quantum spin Hall (QSH) effect, increasing the critical temperature is crucial. A two-dimensional topological insulator (2D-TI) with a sizeable bulk band gap is one of the most promising strategies to reach this goal. Using first-principles calculations, we propose a new 2D-TI, titanium nitride iodide (TiNI) monolayer, which can be exfoliated from a bulk TiNI crystal, thanks to the weak interlayer interaction. We demonstrate that the TiNI monolayer has an inverted band structure accompanied by topologically nontrivial states characterized by a topological invariant of <span class="italic">Z</span><small><sub>2</sub></small> = 1. The band gap (∼50 meV) opened due to spin–orbit coupling (SOC) is available for achieving the QSH effect at room temperature. The band inversion and topologically nontrivial states are robust under external strain, suggesting that the 2D TiNI monolayer lattice could be a versatile platform for hosting nontrivial topological states with potential applications in 2D spintronics and computer technology
Dialoghi piaceuoli del sig. Estefano Guazzo gentil'huomo di Casale di Monferrato : dalla cui famigliare lettione potranno senza stanchezza & satietà non solo gli huomini, ma ancora le donne raccogliere diuersi frutti morali & spirituali ...
Get PDFSign.: [cruz latina]8, 2[cruz latina]6, A-Z, Aa-Bb8, Cc4. -- L. red. y curs. -- Apost. marg. -- ReclamosMarca tip. en port. de Pietro Tini. -- Inic. y frisos grab. xil.[14], 203, [1] h. ; 4
An Axiomatic Semantics for Esterel
No full textAbstractIn this paper we propose an axiomatic semantics for the synchronous language Esterel. We begin with giving a structural operational semantics for Esterel in terms of a labeled transition system (LTS). We prove that bisimulation on LTS states (which correspond to Esterel programs) is a congruence and that our LTS reflects the input/output behavior of programs. So, bisimilar programs are distinguished neither by any Esterel context nor by the external environment, and bisimulation is a reasonable notion of behavioral equivalence. In order to characterize equivalent programs, we give a set of axioms and we prove that they induce an axiomatization over Esterel which is sound and complete modulo bisimulation
Линейная сварка трением TiNi сплава
Get PDFПриведены результаты исследований по линейной сварке трением соединений TiNi – TiNi и TiNi – сталь
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