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The changes in the properties of copper and its alloys as a result of severe plastic deformation (SPD) are reviewed. The literature review shows that contemporary materials science is aimed at solving the problem of producing ultrafine-grained materials with high-angle grain boundaries. With using of the methods of severe plastic deformation, it is possible to obtain so-called bulk nanostructured materials with grain sizes of 0.1-0.2 microns and specific substructures containing the lattice and grain-boundary dislocations. Such structures are characterised by large elastic distortions of the crystal lattice. It is believed that such fine-grained structures should simultaneously provide a high level of plastic and strength characteristics due to special stressed high-angle grains. The article discusses SPD methods such as torsion with shear, equal-channel angular pressing, screw extrusion, all-round forging, rolling with shear, etc. Among the most significant results of SPD, it is worth highlighting the increase in strength, fatigue resistance and elastic properties of the material. These changes make copper and its alloys subjected to SPD very attractive for use in many industries, including electrical engineering, aviation, medicine, etc. [ABSTRACT FROM AUTHOR]

This work studies evolution of copper microstructure during a combined deformation process. The essence of this process is in deformation of copper wire in a rotating equal-channel stepped matrix with subsequent drawing. Deformed wire is examined using transmission electron microscopy and EBSD analysis. After three cycles of deformation, an ultrafine-grained gradient microstructure with a high component of high-angle grain boundaries is obtained. [ABSTRACT FROM AUTHOR]

The relationship between the change in the structural and mechanical properties of metal materials and structural elements and the modification of their magnetic behaviour under the influence of mechanical stresses, temperature and aggressive environments is established in order to create a methodology for both determining the residual resource and increasing the operational reliability of materials and systems. An express method of microstructure assessment by means of determining the change in the magnetoacoustic response of the material is proposed. [ABSTRACT FROM AUTHOR]

The publications in the field of cryogenic-technologies' applications in the processes of the thermal and deformation treatments of metals are reviewed. The most effective fields of the applications of cryogenic liquids and gases for the heat treatment of working tools and metals (titanium, aluminium, and copper alloys) are in the rolling production and heavy engineering in order to improve the product quality, equipment and tool durability, to reduce the impact on the environment and operating personnel. The effects of cryogenic treatment and cooling on the tool life, wear, cutting temperature, surface roughness, dimensional accuracy, and cutting force are considered. As a result, the use of cryogenic processing and cryogenic cooling in machining processes increases the tool life and improves surface roughness as well as reduces the temperature of the machined surface, energy consumption during operation, and, thus, reduces tool wear that contributes to an increase in productivity. The possibility of obtaining and changing the nanostructure of a metal through the cryogenic cooling is also considered. The topic may be of interest for researchers and scientists in the field of metallurgy, materials science, and nanotechnologies. [ABSTRACT FROM AUTHOR]

The methods for fabrication of the functionally-gradient materials, which have a high complex of unique mechanical, technological and special properties, when they working on impact, wear, fatigue, experiencing increased cyclic and alternating loads, are reviewed. Considered materials are used in aerospace engineering, energy, and other industries characterized by extremely unfavourable, extreme operating conditions of critical parts, structural elements, and assemblies. Different methods for fabrication of the gradient structures are considered, in particular, the method of severe plastic deformation of metals and the process of active bending of copper. The effect of grain size, texture, and grain-growth gradients on the deformation mechanisms and mechanical properties of gradient-nanostructured nickel, as well as functionally-gradient ceramic materials are studied. The review may be of interest to researchers and scientists in the field of materials science, metallurgy, and nanotechnology. [ABSTRACT FROM AUTHOR]

Modern materials often have multicomponent alloys, whose properties are determined by their phase and structural composition formed as a result of previous thermomechanical processing. Therefore, the problem of managing the structural state occupies an important place in the overall strategy of developing new materials. Particular attention is drawn to phase transformations in ultrafine systems, in particular, in alloys subjected to severe plastic deformation. In this case, the sample size becomes an important parameter determining the physical properties of the substance and, in particular, its structural and phase compositions. Despite the considerable interest of researchers, until recently, it was not possible to achieve significant theoretical results in this area. Therefore, the development of modern models for describing structural transformations in heterogeneous systems and their application to ultrafine-grained materials seem promising and relevant. [ABSTRACT FROM AUTHOR]

Copyright of Progress in Physics of Metals / Uspehi Fiziki Metallov is the property of G.V. Kurdyumov Institute for Metal Physics, N.A.S.U and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Over the last 20-30 years, severe plastic deformation (SPD) technologies have caused a significant resonance in the production of ultrafine grained and nanostructured materials. However, the growth of demand for such technologies is largely limited by the high cost of making products from such materials due to the high energy and labour intensity of their production. Therefore, this article analyzes modern technologies for the production of ultra-fine grained metals and alloys with high strength and ductility, using relatively simple and inexpensive equipment and with minimal time required for their production. The development and proliferation of continuous casting machines in the second half of the 20th century led to the development of many continuous press methods used for deformation of long billets, among which Conform, Extrolling, Linex and combined rolling-press technologies stand out. Therefore, in the present article all combined and continuous processes currently available for the production of long products with ultrafine grains and nanostructures will be considered. Such structures are fundamentally different from conventional materials, because they combine high strength properties with high ductility. This is relevant for applications where weight, size or special performance characteristics of the parts are important. [ABSTRACT FROM AUTHOR]

This paper presents an overview of the latest trends in the development of severe plastic deformation (SPD) using rolling methods. From many scientific works, it is known that severe plastic deformation provides intense grain grinding up to ultrafine and nanosized grains during multi-cycle deformation. It is also possible to obtain a uniform or gradient grain distribution over the cross-section of the workpiece. During SPD processes, the strength parameters can be increased several times. Of all the methods considered, asymmetric rolling has become the most widespread owing to its simple implementation in production conditions. Most of the known methods and devices for asymmetric rolling are designed for deformation in rolls with a smooth barrel, while the use of rolls with a relief surface allows the processing of metal to obtain a higher level of equivalent strain. Ensuring a high asymmetry level when rolling in relief rolls allows, in addition to the development of shear strain in two transverse directions (height and width), it also provides an additional level of shear strain in the longitudinal direction. In addition to the speed asymmetry, the rolling scheme in relief rolls is also suitable for the implementation of geometric asymmetry when one of the relief rolls has a reduced or increased diameter while maintaining the relief geometry on the roll surface. [ABSTRACT FROM AUTHOR]

Copyright of Progress in Physics of Metals / Uspehi Fiziki Metallov is the property of G.V. Kurdyumov Institute for Metal Physics, N.A.S.U and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, finite element modeling of the forging process in step-wedge strikers of two different configurations was carried out. During the analysis of the results of the shape change and the parameters of the stress-strain state, it was found that the configuration with a wedge and a depression in the cross section is the best option. The microstructure evolution of the metal was simulated during its deformation in step-wedge-shaped strikers of the optimal configuration. For comparative analysis, models with variable values of geometric and technological parameters were studied. It was found that the angle of the junction of the wedge and the depression, as well as the heating temperature of the workpiece, have a significant effect on the intensity of grinding of the initial grain size. The change in the strain rate has a negligible effect on the change in the microstructure. Varying the values of the friction coefficient at the contact of the workpiece and the tool does not affect the intensity of grinding of the initial grain size. [ABSTRACT FROM AUTHOR]

During experimental studies of the equal-channel angular pressing-drawing effect on the microstructure evolution and mechanical properties change, the principal possibility and effectiveness of using the proposed continuous method for forming an ultrafine-grained structure and increasing the strength properties of steel-aluminum wire was proved. The deformation was carried out at ambient temperature in three passes. It is shown that both layers of bimetallic wire are processed unevenly. An aluminum shell with an initial grain size of 22 microns was processed up to 2 microns. The steel core has a different grain size in the transverse and longitudinal sections. With an initial grain size of 18 microns, after deformation the grain size is about 10 microns in the longitudinal section and 8 microns in the transverse section. [ABSTRACT FROM AUTHOR]

The article discusses the reconstruction of the paleonenvironment of the Mesolithic sites Parch-1 and 2 at the Vychegda River valley in Russia. Researchers examined the mineral raw material base of lithic industries and the micro-region's geomorphology for the reconstruction of human occupation and explain the seasonal character of the sites. The researchers also made an analysis of large-scale maps, aerial photographs, and field observations. It notes the dwellings discovered at Parch-2 site, meanwhile there were no dwellings noted at Parch-1, which was more elevated than the other alluvial segment. It also discusses the inhabitants' source of raw materials in making flint tools and presents the Mesolithic fauna found in the region which includes the remains of mammals and bones of birds.