HIGH-SPEED THERMAL-CYCLE PROCESSING OF LOW-CARBON STEEL IN THE INITIALLY HARDENED AND INITIALLY COLD-DEFORMED CONDITION

В работе исследованы процессы формирования структуры и свойств низкоуглеродистой стали 10Х3Г3МФ в различных исходных состояниях при скоростной термоциклической обработке (ТЦО). Установлено, что наибольшее измельчение зеренной структуры аустенита при ТЦО происходит на первом цикле нагрева до 900 °С исходно холоднодеформированной исследуемой стали, при этом формируется наноструктурное состояние мартенсита, что приводит к существенному увеличению уровня механических свойств.The article is concerned with the research of the processes of formation of the structure and properties of low carbon steel 10H3G3MF in different initial states at high speed thermal-cycle processing (TCP). It is shown that the maximum fine crushing of grain structure of austenite with TCP of the researched steel in initially cold-deformed condition occurs at the first cycle of heating to 900 °C, which results in a substantial increase in level of mechanical properties

Nematic twist-bend phase with nanoscale modulation of molecular orientation

A state of matter in which molecules show a long-range orientational order and no positional order is called a nematic liquid crystal. The best known and most widely used (for example, in modern displays) is the uniaxial nematic, with the rod-like molecules aligned along a single axis, called the director. When the molecules are chiral, the director twists in space, drawing a right-angle helicoid and remaining perpendicular to the helix axis; the structure is called a chiral nematic. Here using transmission electron and optical microscopy, we experimentally demonstrate a new nematic order, formed by achiral molecules, in which the director follows an oblique helicoid, maintaining a constant oblique angle with the helix axis and experiencing twist and bend. The oblique helicoids have a nanoscale pitch. The new twist-bend nematic represents a structural link between the uniaxial nematic (no tilt) and a chiral nematic (helicoids with right-angle tilt)

Nematic Twist-Bend Phase with Nanoscale Modulation of Molecular Orientation

Peer reviewedPublisher PD

Laws of formation of structure and properties in cold-deformed low-carbon structural steel under incomplete quenching

The effect of quenching from the intercritical temperature range on formation of martensite-ferrite structure in steel 10Kh3G3MFS deformed preliminarily by the method of cold radial forging is considered. The microstructure of the steel is studied using optical and scanning electron microscope

Mechanisms of grain structure evolution in a quenched medium carbon steel during warm deformation

The as-quenched medium-carbon low-alloy Fe-0.36wt.%C-1wt.%Cr steel was subjected to warm deformation via uniaxial compression at temperatures of 400–700 С and strain rates of 10-4-10-2s-

Coulomb singularity effects in tunnelling spectroscopy of individual impurities

Non-equilibrium Coulomb effects in resonant tunnelling processes through deep impurity states are analyzed. It is shown that Coulomb vertex corrections to the tunnelling transfer amplitude lead to a power-law singularity in current- voltage characteristicsComment: 7 pages, 2 figure

Non-thermal high-energy emission from colliding winds of massive stars

Colliding winds of massive star binary systems are considered as potential sites of non-thermal high-energy photon production. This is motivated merely by the detection of synchrotron radio emission from the expected colliding wind location. Here we investigate the properties of high-energy photon production in colliding winds of long-period WR+OB-systems. We found that in the dominating leptonic radiation process anisotropy and Klein-Nishina effects may yield spectral and variability signatures in the gamma-ray domain at or above the sensitivity of current or upcoming gamma-ray telescopes. Analytical formulae for the steady-state particle spectra are derived assuming diffusive particle acceleration out of a pool of thermal wind particles, and taking into account adiabatic and all relevant radiative losses. For the first time we include their advection/convection in the wind collision zone, and distinguish two regions within this extended region: the acceleration region where spatial diffusion is superior to convective/advective motion, and the convection region defined by the convection time shorter than the diffusion time scale. The calculation of the Inverse Compton radiation uses the full Klein-Nishina cross section, and takes into account the anisotropic nature of the scattering process. This leads to orbital flux variations by up to several orders of magnitude which may, however, be blurred by the geometry of the system. The calculations are applied to the typical WR+OB-systems WR 140 and WR 147 to yield predictions of their expected spectral and temporal characteristica and to evaluate chances to detect high-energy emission with the current and upcoming gamma-ray experiments. (abridged)Comment: 67 pages, 24 figures, submitted to Ap