Impact of indentor sliding velocity and loading repetition factor on shear strain and structure dispersion in nanostructuring burnishing

The article probes into a relationship of the shear strain intensity and the shear strain rate in the surface layer and the sliding velocity of a spherical indentor and its loading repetition factor. It brings forward an experimental procedure to evaluate the shear strain intensity and rate by analyzing the geometrical parameters of the bulge of plastically edged metal and the thickness of the shifted layer relative to different sliding velocities and feed rates. © 2019 by University of Niš, Serbia

Research into Dry Turning of Welded Surface by Replaceable Cutting Insert with Closed Loop Heat Removal

A special tool has been devised incorporating a closed loop system based on Peltier thermoelectric couples to cool replaceable hard alloy inserts. Experimental research has been done into dry turning of a X20Cr13 steel welded surface with a SECO cubic boron nitride circular plate at the cutting speed increasing from 100 to 300 m/min. It has been determined that Ra surface roughness decreases by 22% while Rz surface roughness goes down by 26%; in addition, the wear flat of tool tips diminishes by 17%. © 2018 Published under licence by IOP Publishing Ltd.The work was supported by Ministry of Education and Science of the Russian Federation, contract № 02.G25.31.0148 with Sverdlovsk Instrumental Plant within the framework of Research and Development Project No Н979.210.007/15, July 28, 2015 for the federal autonomous educational institution of higher education “Ural Federal University”

Impact of Friction Stir Processing Parameters on Forming the Structure and Properties in AISI 420 Steel Surface Layer

Research has been done into the influence of friction thermomechanical treatment parameters on forming the structure and properties in a surface layer of 20X13 steel. The paper presents a theoretical approach towards controlling the process variables. A hardened layer with a thickness of 1,7 mm was obtained after 20X13 steel had been subjected to the process. The thickness of the layer that had a microhardness of ≥600HV0,05 turned out to be about 0,75mm while the microstructure of the hardened layer was martensitic, martensitic and perlitic with dispersed inclusions of carbides. It was established that the feed has the biggest influence on the thickness of the hardened layer.     Keywords: friction stir processing, rotation speed, tool feed, normal force, microhardness, microstructure

Effects of Sliding Velocity and Thermal Conduction of the Tool on X20Cr4 Steel Friction Coefficient and Structure in Nanostructuring Burnishing

The developmental study has succeeded in finding how the sliding velocity of an indenter affects the friction coefficient and changes the structure and phase state in the surface layer of a X20Cr13 stainless steel when nanostructuring burnishing is done with a tool with no heat removal and, alternatively, when the tool is equipped with a cooling system. It has been shown that structural dispersion of the treated material results in obtaining 20⋯80 nm nanocrystallites if the friction coefficient of the spherical synthetic diamond indenter is within 0.15⋯0.18 nm. Application of a compact cooling system, based on Peltier's thermoelectric module, made it possible to stabilize the friction coefficient at 0.17 and to increase the sliding velocity from 13 m/min, this being the case of no heat removal, to 45 m/min in the case when the cooling system having a cooling performance of 120 W was used. TEM and SEM analyses of the surface layer structure confirmed that there is a correlation between the friction coefficient and the size of nanocrystallites and the thickness of the dispersed layer. EBSD analysis of the structure showed that a maximum permissible sliding velocity can be established as referenced to the nucleation and growth of γ-phase grains in the nanostructured layer caused by heating of the material under deformation and reaching the temperature beyond the point α→γ phase transition as well as by behavior of dynamic recrystallization. It was established that the heat removal ensures suppression of dynamic recrystallization when the sliding velocity is increased up to 50 m/min. © 2018 Published under licence by IOP Publishing Ltd

The analysis of speed increase perspectives of nanostructuring burnishing with heat removal from the tool

The work deals with investigation of opportunities of speed increase of nanostructuring burnishing due to heat removal from the contact area of severe plastic deformation using friction via the tool. The work has analyzed changes of the structure, thickness and quality of the modified layer, while increasing treatment speed of the tool without heat removal and with heat-cooling system. It is established that the cooling system of the tool indenter with a cooling capacity of 10 W allows for the two-times increase of the critical speed of burnishing, and when exceeding this speed, the deformable material does not turn into a nanostructuring state. It is shown that heat removal provides for a stable maintenance of the indenter temperature, an increase in thickness of the nanostructured layer up to 5 μm and roughness up to Ra=150 nanometers at processing speed up to 0.17 m/s

ИСПОЛЬЗОВАНИЕ ФЛУОРИМЕТРИИ В БЛИЖНЕЙ ИК-ОБЛАСТИ С ФОТОГРАФИЧЕСКОЙ РЕГИСТРАЦИЕЙ СИГНАЛА В МЕТОДЕ «ОТПЕЧАТКОВ ПАЛЬЦЕВ» С ДОБАВКОЙ ФЛУОРОФОРА К ОБЪЕКТУ: ДИСКРИМИНАЦИЯ ЯБЛОЧНЫХ СОКОВ

The application of dyes, that fluoresce in the near infrared (NIR, 700-800 nm) region, for the recognition of samples using a fingerprinting method with the addition of fluorophores to the samples (“fluorescent eye”) is proposed. The technique has been successfully applied to the classification of samples of various nature. In the current work, this strategy has been tested on the example of discrimination of 17 samples of apple juice from different manufacturers, purchased at different times. An indolenine series heptamethine carbocyanine dye in the presence of surfactants was used as the added fluorophore, red LEDs were used as an excitation source, and the signal was recorded using a digital camera with an additional IR filter installed; a spectrofluorimeter with a 96-well plate accessory was used to record the spectra. Photographic images were processed using Unscrambler X and Excel software. The results were presented using the following coordinates: intensity of NIR fluorescence - intensity of visible light reflection (using the photographic images). It was found that such presentation allowed the samples to be divided into groups associated with the manufacturer. We have also obtained intrinsic fluorescence spectra, including those with the addition of NIR dye, and these results were processed by the principal component analysis. It was possible to distinguish 5–6 groups of samples by their intrinsic emission, not counting the blank, while the spectra with the addition of the dye allowed to isolate the largest number of groups of samples (9). At the same time, the classification using spectra did not allow juices to be grouped by the producer. Also, obtaining photographs using a visualizer was easier and faster than recording the fluorescence spectra. The joint processing of emission spectra and photographs did not improve the quality of discrimination.Keywords: fingerprinting method, NIR fluorimetry, apple juice, principal component analysisDOI: http://dx.doi.org/10.15826/analitika.2022.26.1.005E.V. Skorobogatov, I.A. Stepanova, V.S. Orekhov, M.K. Beklemishev Department of Chemistry, Lomonosov Moscow State University, Russin Federation, 119991, GSP-1, Moscow, Leninskie gory, 1, building 3Предложено использовать красители, флуоресцирующие в ближней ИК (БИК) области спектра (700–800 нм), для распознавания объектов методом «отпечатков пальцев», основанным на добавке флуорофоров к объекту («флуоресцентный глаз»). Метод успешно применяется в классификации объектов различной природы. В данной работе метод опробован на примере дискриминации 17 образцов яблочного сока разных производителей, выпущенных в разное время. В качестве добавляемого флуорофора использовали гептаметиновый карбоцианиновый краситель индоленинового ряда в присутствии ПАВ, в качестве источника излучения – красные светодиоды, а сигнал регистрировали с помощью цифрового фотоаппарата с дополнительным ИК-светофильтром; для записи спектров применяли спектрофлуориметр с приставкой для 96-луночного флуориметрического планшета. Фотографические изображения обрабатывали с помощью стандартного программного обеспечения Unscrambler X и Excel. Результаты представили в координатах: интенсивность БИК-флуоресценции – интенсивность отражения видимого света (с использованием соответствующих фотографий). Обнаружили, что такое представление позволяет разделить образцы на группы, связанные с производителем. Получали также спектры собственной флуоресценции, в том числе с добавкой БИК-красителя, обрабатывая эти результаты методом главных компонент. По собственной эмиссии можно выделить 5–6 групп образцов, не считая контрольного, тогда как по спектрам с добавкой красителя удается добиться выделения наибольшего числа групп образцов (девять). При этом классификация с использованием спектров не позволяет группировать соки по производителям. Кроме того, получение фотографий с помощью визуализатора проще и экспресснее, чем регистрация спектров флуоресценции. Совместная обработка эмиссионных спектров и фотографий не позволяет повысить качество дискриминации образцов.Ключевые слова: метод «отпечатков пальцев», флуориметрия в ближней ИК-области, яблочный сок, метод главных компонентDOI: http://dx.doi.org/10.15826/analitika.2022.26.1.00

Crystal Undulator As A Novel Compact Source Of Radiation

A crystalline undulator (CU) with periodically deformed crystallographic planes is capable of deflecting charged particles with the same strength as an equivalent magnetic field of 1000 T and could provide quite a short period L in the sub-millimeter range. We present an idea for creation of a CU and report its first realization. One face of a silicon crystal was given periodic micro-scratches (grooves), with a period of 1 mm, by means of a diamond blade. The X-ray tests of the crystal deformation have shown that a sinusoidal-like shape of crystalline planes goes through the bulk of the crystal. This opens up the possibility for experiments with high-energy particles channeled in CU, a novel compact source of radiation. The first experiment on photon emission in CU has been started at LNF with 800 MeV positrons aiming to produce 50 keV undulator photons.Comment: Presented at PAC 2003 (Portland, May 12-16

Условия наноструктурирования поверхностей сталей скользящим индентором

This paper proposes an approach to optimizing the temperature.velocity regime of severe plastic deformation induced by slyding indenter based on determining the optimal value of the Zener.Hollomon parameter based on the criterion of the maximum volume fraction of nanocrystallites in the surface layer.В работе предложен подход к оптимизации температурно.скоростного режима интенсивной пластической деформации, развиваемой скользящим индентором, на основе определения оптимального значения параметра Зинера–Холломона по критерию максимальной объемной фракции нанокристаллитов в поверхностном слое