Studying the compactibility of the VT22 high-strength alloy powder obtained by the PREP method

Compression curves are plotted for VT22 high-strength alloy powder under conditions of uniaxial compression at room temperature. The density of the compacted briquette at the loading and unloading stages is determined. It is demonstrated that strong interparticle bonds are formed in the area of the action of shear deformation. The results are supposed to be used to identify the flow model of the material studied and to perform the subsequent numerical modeling of the compaction process. © 2017 Author(s)

The use of intermediate inserts for CO 2 laser welding of steel AISI 321 and a Grade 2 titanium alloy

The paper studies the structure, chemical and phase compositions, hardness and strength of welded joints obtained in AISI 321 steel and Grade 2 titanium alloy sheets by CO 2 continuous laser with the use of intermediate Cu, Ni and Ag-Cu-Zn alloy inserts. It is demonstrated that the maximum strength of welded joints is achieved by the welding conditions enabling one to form multiphase structures with intermetallics in the material of a weld, rather than only those based on solid solutions. © 2018 Author(s)

The density of deformation distribution in a plane of VT1-00 sample under uniaxial strain

The inhomogeneity of the plastic deformation field is a common property of all polycrystalline materials. Numerical indicators of deformation inhomogeneity are defined using various experimental methods. The grade grid method with grid sizes commensurable with the average size of the material grain is meant to be the classical one. This method allows obtaining full characteristics of the field inhomogeneity for mesodeformations (at the grain level and inside the individual grains of the material). The grid method is considerably laborious and has limitations in accuracy. Statistically reliable data require performing a large number of measurements. The coordinates of grid points are measured by a visual observation of the magnified image in a microscope eyepiece. The development of modern means of computer technology and digital video cameras with high resolution allows using more advanced experimental methods. This article based on the method of digital image correlation provides the technique for defining statistical parameters of the deformation field inhomogeneity in the surface layer of the sample under loading. On the basis of digital images correlation method we propose a technique aimed at identification of statistical parameters of the deformation field inhomogeneity in a surface layer of the sample. The tests were performed using uniaxial strain of plane VT1-00 titanium samples. It is a single-phase material (α– phase) with the hexagonal crystal grid. The metallographic studies of material structure of the sample have been performed. The average grain size is determined using the random linear intercept method. The grains are equiaxial. The sample material has annealing twins. There are fields of vectors for irreversible displacements, components of the tensor for elastic-plastic deformations in orthogonal directions about the axis of the sample and shear deformations in a plane of the sample that have been determined. The third component of linear deformations has been defined according to the material’s incompressibility. The deformation relief on a surface of the sample during the strain was used as reference targets. The main logarithmic elastic-plastic deformations, its intensity and random Nadai-Lode parameters characterizing the stress-strain state of individual sections of the sample’s surface have been calculated. Distribution densities of the specified parameters have been built up and correlation functions of deformation intensity have been obtained. The results of the study have been compared with the experimental data obtained by the grain grid method under uniaxial strain of titanium grade VТ1–0 samples, similar in chemical composition to titanium VT1-00. There are more impurities in titanium VТ1–0. © PNRPU

Effect of ion irradiation on low-cycle fatigue of pressed profiles of the V95 alloy after artificial aging

The effect of 20-40-keV Ar+ ion irradiation on the fatigue resistance of hot-pressed V95 alloy (Al-Zn-Mg-Cu system) profiles 6 mm thick after quenching and artificial aging (140°, 16 h) has been investigated. The use of the irradiation conditions (E = 40 keV, j = 500 μA/cm2), under which the profiles were briefly heated to a temperature of 200°C, is found to reduce the strength properties of the alloy significantly, which does not meet the specified requirements. Irradiation conditions, which enable one to avoid significant heating of a target at E = 20 keV and j = 400 μA/cm2, do not affect the fatigue resistance significantly at all fluences of F = 1•1015, 1•1016, 1•1017 cm-2. © 2019 IOP Publishing Ltd. All rights reserved.Russian Foundation for Basic Research, RFBR: № 19-08-00802-а, 19-08-00802-а.This work was supported in part by RFBR grant № 19-08-00802-а

Ion irradiation effect (Аr+, E = 20-40 keV) on the mechanical properties and microstructure of aluminum V95 alloy

The effect of 20-40 keV Ar+ ion irradiation on the mechanical properties and structural and phase state of hot-pressed profiles 6 mm thick made of an V95 alloy (Al-Zn-Mg-Cu system) after artificial aging has been studied. Irradiation (without causing heating) at fluences of 2∙1015 cm-2 and 1∙1016 cm-2 has been revealed to increase the relative elongation by 5%, without changing the strength characteristics. Electron microscopy examination has showed that irradiation has an effect on the state of the subgrain structure of the alloy. Irradiation at these fluences results in partial enlargement of the subgrain structure, and at higher fluence of 9.4∙1016 cm-2 it completely transforms the structure into coarse-grained one. At a distance of 150 µm from the irradiated surface, there is a slight increase in the subgrain size. The irradiation changes the morphology of Al6(Fe,Mn) intermetallic compounds in both the surface layer and the sample volume; namely, it sharply decreases the bulk density of lath-shaped intermetallic compounds and increases the density of the equiaxed ones. The degree of influence depend on the irradiation mode. © 2020 Institute of Physics Publishing. All rights reserved.This work was supported in part by RFBR grant № 19-08-00802-а

Study of luders deformation in ultrafine low-carbon steel by the digital image correlation technique

The studied steel was a low-carbon microalloyed steel of type 08G2B, used for pipes with an outer diameter of 1420 mm for natural gas transportation with an operation pressure of 11.8 MPa with the chemical composition characterized by a low-carbon content (0.08 wt.%) with additions of Mn, Cr, Mo, Ni and microalloying elements (∑(Nb, V, Ti) ≈ 0.10 wt.%). Secondary refining and continuous casting followed by thermo-mechanical controlled processing (TMCP) with a strict temperature-reduction route and control of the post-deformation cooling rate are used to produce high-strength welded X80 and higher-grade pipes with an extremely ultrafine heterophase structure (d =1– 3 μm) and high Charpy energy of more than 250 J/cm2 at –40°С. Usually sheet metal is not subjected to heat treatment. However, pipes can be heated by applying an anti-corrosion coating at 200 – 250°C or by welding in a heat affected zone, which initiates the strain aging effect (SAE). The appearance of SAE can also occur upon prolonged exposure of pipes in the area of climatic temperatures, as well as in the course of installation and operation of pipelines, which inevitably leads to a change in the mechanical properties of the metal. Luders deformation in ultrafine low-carbon microalloyed steel X80 has been studied upon tensile testing by the digital image correlation technique. Two mechanisms of Luders deformation are shown to be observed depending on the strain ageing effect. It is determined that the mechanical behavior of the material at the stage of uniform deformation strongly correlates with the type of Luders deformation. © 2019, Institute for Metals Superplasticity Problems of Russian Academy of Sciences. All rights reserved.Government Council on Grants, Russian FederationБлагодарности/Acknowledgements. Работа выпол нена в УрФУ при финансовой поддержке постановления № 211 Правительства Российской Федерации, контракт № 02. А03.21.0006, а также в ИМАШ УрО РАН в рамках темы государственного задания №0391‑2016‑0004./The work was performed cooperatively in Ural Federal University with the support of the Government of the Russian Federation, resolution no. 211, contract no. 02. А03.21.0006 and in Institute of Engineering Science (Ural Branch of RAS) within the state theme no. 0391‑2016‑0004

ВЛИЯНИЕ ДЕФОРМАЦИОННОЙ ОБРАБОТКИ НА СВОЙСТВА И СТРУКТУРУ ПОЛУФАБРИКАТОВ, ПОЛУЧЕННЫХ ТВЕРДОФАЗНОЙ КОНСОЛИДАЦИЕЙ ТИТАНОВОЙ ГУБКИ

The influence of the density of titanium briquettes formed from titanium sponge of TG-100 brand and the presence of hydrogen in them on the force of direct briquette compacting at 600 °C, density, and mechanical properties of pressed rods is investigated experimentally. The results show that the smaller compacting force is required while the density and plasticity of compacted rods evaluated att = 600 °C increase.Экспериментально исследовано влияние плотности титановых брикетов, полученных из титановой губки марки ТГ-100, и наличия в них водорода на усилие прямого прессования брикетов при температуре 600 °C, плотность и механические свойства прессованных прутков. Полученные результаты показывают, что для более плотных брикетов, легированных водородом, требуется меньшее усилие прессования, а плотность и пластичность прессованных прутков, оцененные при t = 600 °C, увеличиваются

Lüders deformation in specimens made of normalized 09G2S steel

The features of Lüders deformation in the normalized 09G2S steel are studied by the methods of digital image correlation, topography, and scanning electron microscopy of specimen faces. The paper studies the appearance, growth, structure, and location of deformation bands, as well as plastic strain in them. © 2021 Elsevier B.V.. All rights reserved.Ministry of Education and Science of the Russian Federation, Minobrnauka: AAAA-A18-118020190116-6The study was performed at the IMP UB RAS under a state assignment from the Ministry of Education and Science of Russia (theme Structure, No. AAAA-A18-118020190116-6) and within the research plan of the IES U

ВЛИЯНИЕ НАПРЯЖЕННОГО СОСТОЯНИЯ НА ПРЕДЕЛЬНУЮ ПЛАСТИЧНОСТЬ МЕДНОЙ КАТАНКИ М00К

A fracture locus of copper rolled wire depending on the stressed-state coefficient (k) and Lode–Nadai coefficient (μσ) is constructed. The region of using this fracture locus to calculate the damage is limited by values k < 1,4 and –1 < μσ < 0. To construct the fracture locus, we performed twisting tests of cylindrical samples and tension tests of cylindrical and plane samples in air and in a chamber with a controlled liquid pressure, which was varied from 49 to 375 MPa. The constructed fracture locus will be further used for the calculations of damage of copper rolled wire in drawing processes, by the results of which, recommendations for lowering the wire breakage during drawing will be elaborated.Получена диаграмма пластичности медной катанки в зависимости от коэффициента напряженного состояния (k) и коэффициента Лоде–Надаи (μσ). Область использования этой диаграммы для расчетов поврежденности ограничивается значениями k < 1,4; –1 < μσ < 0. Для построения диаграммы пластичности проводились испытания на кручение цилиндрических образцов, на растяжение цилиндрических и плоских образцов на воздухе и в камере с регулируемым давлением жидкости, которые варьировалось от 49 до 375 МПа. Полученная диаграмма пластичности в дальнейшем будет служить для расчетов поврежденности медной катанки в процессах волочения, по результатам которых будут выработаны рекомендации по снижению обрывности проволоки при волочении