Nanosize phases formation under low carbon steel thermomechanical strengthening

The quantitative regularities of structure phase states formation in different Hbeam cross sections under accelerated cooling in different regimes are established. The gradient structure-phase states formation being characterized by the regular change of dislocation substructure parameters, nanosized range -phase fragments and cementite particles on cross section are revealed by methods of transmission electron diffraction microscopy. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2068

Nanosize Carbides Formation and Fatigue Life Increase of Stainless Steel by Electron Beam Treatment

Electron – beam treatment with 20 J/cm2 energy density of Fe-0.20C-23Cr-18Ni stainless steel increases fatigue life up to 2.1 times. Fracture surface investigations have been carried out by the methods of scanning and transmission diffraction electron microscopy and layer-by-layer analysis of structural phase states and defect substructure of steel subjected to the multicyclic fatigue tests, has been made as well. Nanosize (Cr,Fe)23C6 carbides formation and physical reasons of steel fatigue life increase by electron – beam treatment have been found out. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3480

The structure and properties of a hypoeutectic silumin subjected to complex electron–ion-plasma processing

The layer-by-layer analysis of structural–phase states and tribological properties of hypoeutectic АК10М2Н-type silumin at the depth up to 170 μm after the complex processing is carried out by the state-of-the-art methods of physical materials science. It involves the electroexplosion alloying with titanium and yttrium-oxide powder in different ratios followed by electron-beam processing.Методами сучасного фізичного матеріалознавства проведено пошарову аналізу структурно-фазових станів і трибологічних властивостей доевтектичного силуміну марки АК10М2Н на глибині до 170 мкм після комплексного оброблення. Воно полягало в електропідривному леґуванні титаном і порошком оксиду ітрію в різних співвідношеннях з подальшим електронно-пучковим обробленням.Методами современного физического материаловедения проведён послойный анализ структурно-фазовых состояний и трибологических свойств доэвтектического силумина марки АК10М2Н на глубине до 170 мкм после комплексной обработки. Она заключалась в электровзрывном легировании титаном и порошком оксида иттрия в разных соотношениях с последующей электронно-пучковой обработкой

Nanosize Structure Phase States of Ti Surface Layer Formed During Electroexplosive Carboborating

The electroexplosive carboborating leads to a significant (up to 12 times) increase in microhardness of the titanium irradiated surface. It is established that the thickness of strengthened surface layer reaches ~ 125 μm. The formation of nanosize structure-phase states in Ti surface layers during electroexplosive carboborating was carried out by methods of scanning and transmission diffraction electron microscopy. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3480

Nanostructure Formation in Superior Quality Rails

Using transmission electron microscopy methods the layer by layer analysis of the bulk hardened superior quality rails is carried out and the quantitative parameters of structure, phase state and defect substructure gradients are established. The gradient character of changing of structure-phase states and dislocation substructure along the cross section of rail head is revealed. The oil bulk hardening of superior quality rails is accompanied by the formation of morphologically different structure, being produced according to the shear and diffusion of γ-α transformation. The base structure volume is formed by the diffusion mechanism and is consisted of plate pearlite grains, free ferrite grains and grains of ferrite-carbide mixture. The presence of the bend extinction contours testifying to curvature-torsion of crystal lattice is revealed on electron microscope images. The analysis of far acting internal field stresses created by interfaces of cementite plates of pearlite grains and interfaces of pearlite and ferrite grains is carried out. It is shown that the interface boundaries globular cementite particles-matrix are the possible places of microcracks initiation

Nanostructure Formation in Superior Quality Rails

Using transmission electron microscopy methods the layer by layer analysis of the bulk hardened superior quality rails is carried out and the quantitative parameters of structure, phase state and defect substructure gradients are established. The gradient character of changing of structure-phase states and dislocation substructure along the cross section of rail head is revealed. The oil bulk hardening of superior quality rails is accompanied by the formation of morphologically different structure, being produced according to the shear and diffusion of γ-α transformation. The base structure volume is formed by the diffusion mechanism and is consisted of plate pearlite grains, free ferrite grains and grains of ferrite-carbide mixture. The presence of the bend extinction contours testifying to curvature-torsion of crystal lattice is revealed on electron microscope images. The analysis of far acting internal field stresses created by interfaces of cementite plates of pearlite grains and interfaces of pearlite and ferrite grains is carried out. It is shown that the interface boundaries globular cementite particles-matrix are the possible places of microcracks initiation

Nanosize phases formation under low carbon steel thermomechanical strengthening

The quantitative regularities of structure phase states formation in different Hbeam cross sections under accelerated cooling in different regimes are established. The gradient structure-phase states formation being characterized by the regular change of dislocation substructure parameters, nanosized range -phase fragments and cementite particles on cross section are revealed by methods of transmission electron diffraction microscopy. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2068

Magnons, their Solitonic Avatars and the Pohlmeyer Reduction

We study the solitons of the symmetric space sine-Gordon theories that arise once the Pohlmeyer reduction has been imposed on a sigma model with the symmetric space as target. Under this map the solitons arise as giant magnons that are relevant to string theory in the context of the AdS/CFT correspondence. In particular, we consider the cases S^n, CP^n and SU(n) in some detail. We clarify the construction of the charges carried by the solitons and also address the possible Lagrangian formulations of the symmetric space sine-Gordon theories. We show that the dressing, or Backlund, transformation naturally produces solitons directly in both the sigma model and the symmetric space sine-Gordon equations without the need to explicitly map from one to the other. In particular, we obtain a new magnon solution in CP^3. We show that the dressing method does not produce the more general "dyonic" solutions which involve non-trivial motion of the collective coordinates carried by the solitons.Comment: 52 page

Giant Magnons on CP^3 by Dressing Method

We consider classical string spectrum of R x CP^3, and construct a family of solutions with residual SU(2) symmetry by the dressing method on SU(4)/U(3) sigma model. All of them obey the square-root type dispersion relation, as is expected from the su(2|2) symmetry. A single dyonic giant magnon is not found in this approach.Comment: 1+29 pages, 1 figure, v2: a figure and references added, minor corrections, v3: remarks on semiclassical quantization added. To be published in JHE

Dressed Giant Magnons on CP^3

A new example of AdS/CFT duality relating IIA string theory on AdS_4 x CP^3 to N=6 superconformal Chern-Simons theory has recently been provided by ABJM. By now a number of papers have considered particular giant magnon classical string solutions in the CP^3 background, corresponding to excitations in the spin chain picture of the dual field theory. In this paper we apply the CP^3 = SU(4)/S(U(3) x U(1)) dressing method to the problem of constructing general classical string solutions describing various configurations of giant magnons. As a particular application we present a new giant magnon solution on CP^3. Interestingly the dressed solution carries only a single SO(6) charge, in contrast with the dyonic magnons found in previous applications of the dressing method.Comment: 13 pages, harvmac; v3: fixed misstatement of the dispersion relation(!), v3: typos fixed and a few clarifying remarks adde