778 research outputs found

    Grain boundary segregation in UFG alloys processed by severe plastic deformation

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    Grain boundary segregations were investigated by Atom Probe Tomography in an Al-Mg alloy, a carbon steel and Armco\trademark Fe processed by severe plastic deformation (SPD). In the non-deformed state, the GBs of the aluminium alloy are Mg depleted, but after SPD some local enrichment up to 20 at.% was detected. In the Fe-based alloys, large carbon concentrations were also exhibited along GBs after SPD. These experimental observations are attributed to the specific structure of GBs often described as "non-equilibrum" in ultra fine grained materials processed by SPD. The grain boundary segregation mechanisms are discussed and compared in the case of substitutional (Mg in fcc Al) and interstitial (C in bcc Fe) solute atoms

    ΠŸΡ€Π΅Π΄ΠΏΠΎΡΡ‹Π»ΠΊΠΈ примСнСния ΠΏΡ€ΠΎΡΠ²Π΅Ρ‡ΠΈΠ²Π°ΡŽΡ‰Π΅ΠΉ элСктронной микроскопии ΠΊΠ°ΠΊ гСохимичСской ΠΌΠ΅Ρ‚ΠΎΠ΄ΠΈΠΊΠΈ выявлСния ΠΌΠΈΠ³Ρ€Π°Ρ†ΠΈΠΎΠ½Π½Ρ‹Ρ… ΠΌΠΈΠ½Π΅Ρ€Π°Π»ΡŒΠ½Ρ‹Ρ… Ρ„ΠΎΡ€ΠΌ Π½Π°Π΄ ΡƒΠ³Π»Π΅Π²ΠΎΠ΄ΠΎΡ€ΠΎΠ΄Π½Ρ‹ΠΌΠΈ Π·Π°Π»Π΅ΠΆΠ°ΠΌΠΈ

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    ΠΠΊΡ‚ΡƒΠ°Π»ΡŒΠ½ΠΎΡΡ‚ΡŒ исслСдования обусловлСна Π½Π΅ΠΎΠ±Ρ…ΠΎΠ΄ΠΈΠΌΠΎΡΡ‚ΡŒΡŽ Ρ€Π°Π·Ρ€Π°Π±ΠΎΡ‚ΠΊΠΈ ΠΌΠ΅Ρ‚ΠΎΠ΄ΠΈΠΊΠΈ нахоТдСния ΠΈ опрСдСлСния ΠΌΠΈΠ³Ρ€Π°Ρ†ΠΈΠΎΠ½Π½Ρ‹Ρ… Ρ„ΠΎΡ€ΠΌ мСталличСских соСдинСний Π½Π°Π΄ ΠΊΠΎΠ½Ρ‚ΡƒΡ€Π°ΠΌΠΈ ΡƒΠ³Π»Π΅Π²ΠΎΠ΄ΠΎΡ€ΠΎΠ΄Π½Ρ‹Ρ… Π·Π°Π»Π΅ΠΆΠ΅ΠΉ Π½Π° повСрхности Π—Π΅ΠΌΠ»ΠΈ, Ρ‚Π°ΠΊ ΠΊΠ°ΠΊ ΡΡƒΡ‰Π΅ΡΡ‚Π²ΡƒΡŽΡ‰Π°Ρ Π² настоящСС врСмя информация ΠΎ возмоТности пСрСноса ΠΌΠ΅Ρ‚Π°Π»Π»ΠΎΠ² с уровня Π·Π°Π»Π΅ΠΆΠΈ Π·Π°Ρ‡Π°ΡΡ‚ΡƒΡŽ ΠΏΡ€ΠΎΡ‚ΠΈΠ²ΠΎΡ€Π΅Ρ‡ΠΈΠ²Π°, Ρ‡Ρ‚ΠΎ ставит ΠΏΠΎΠ΄ сомнСниС саму Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡ‚ΡŒ гСохимичСских поисков ΡƒΠ³Π»Π΅Π²ΠΎΠ΄ΠΎΡ€ΠΎΠ΄Π½Ρ‹Ρ… Π·Π°Π»Π΅ΠΆΠ΅ΠΉ Π½Π° основС ΠΈΠ½Ρ„ΠΎΡ€ΠΌΠ°Ρ†ΠΈΠΈ ΠΎ содСрТании ΠΌΠ΅Ρ‚Π°Π»Π»ΠΎΠ² Π² приповСрхностных Π³ΠΎΡ€ΠΈΠ·ΠΎΠ½Ρ‚Π°Ρ…. ΠžΠ±ΡΡƒΠΆΠ΄Π°Π΅ΠΌΠ°Ρ ΠΌΠ΅Ρ‚ΠΎΠ΄ΠΈΠΊΠ° сбора ΠΈ Π°Π½Π°Π»ΠΈΠ·Π° позволяСт ΠΈΠ·ΡƒΡ‡Π°Ρ‚ΡŒ Π½Π°Π½ΠΎΡ€Π°Π·ΠΌΠ΅Ρ€Π½Ρ‹Π΅ соСдинСния ΠΌΠ΅Ρ‚Π°Π»Π»ΠΎΠ², ΠΌΠΈΠ³Ρ€ΠΈΡ€ΡƒΡŽΡ‰ΠΈΡ… Π² составС Π³Π°Π·ΠΎΠ²ΠΎΠ³ΠΎ ΠΏΠΎΡ‚ΠΎΠΊΠ° Π΄ΠΎ повСрхности Π—Π΅ΠΌΠ»ΠΈ. ΠŸΠΎΡΠ²Π»ΡΠ΅Ρ‚ΡΡ Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡ‚ΡŒ установлСния происхоТдСния Π½Π°ΠΉΠ΄Π΅Π½Π½ΠΎΠ³ΠΎ Π½Π°Π½ΠΎΡ€Π°Π·ΠΌΠ΅Ρ€Π½ΠΎΠ³ΠΎ мСталличСского соСдинСния с Π΄ΠΎΠΏΡƒΡΡ‚ΠΈΠΌΠΎΡΡ‚ΡŒΡŽ Π΄ΠΎΠΊΠ°Π·Π°Ρ‚ΡŒ Π³Π»ΡƒΠ±ΠΈΠ½Π½ΡƒΡŽ ΠΏΡ€ΠΈΡ€ΠΎΠ΄Ρƒ происхоТдСния вСщСства, Π½Π°ΠΉΠ΄Π΅Π½Π½ΠΎΠ³ΠΎ Π½Π° Π΄Π½Π΅Π²Π½ΠΎΠΉ повСрхности. ЦСль Ρ€Π°Π±ΠΎΡ‚Ρ‹: ΠΎΠ±Π·ΠΎΡ€ ΠΈ Π°Π½Π°Π»ΠΈΠ· ΡΡƒΡ‰Π΅ΡΡ‚Π²ΡƒΡŽΡ‰ΠΈΡ… Π·Π½Π°Π½ΠΈΠΉ ΠΎ гСохимичСских ΠΌΠ΅Ρ‚ΠΎΠ΄Π°Ρ… поисков мСстороТдСний Π½Π΅Ρ„Ρ‚ΠΈ ΠΈ Π³Π°Π·Π°; ΠΌΠΎΠ΄Π΅Π»ΠΈΡ€ΠΎΠ²Π°Π½ΠΈΠ΅ Π½ΠΎΠ²ΠΎΠΉ гСохимичСской ΠΌΠ΅Ρ‚ΠΎΠ΄ΠΈΠΊΠΈ, связанной с исслСдованиСм ΠΎΠ±Ρ€Π°Π·Ρ†ΠΎΠ² Π½Π° ΠΏΡ€ΠΎΡΠ²Π΅Ρ‡ΠΈΠ²Π°ΡŽΡ‰Π΅ΠΌ элСктронном микроскопС, с Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡ‚ΡŒΡŽ установлСния частиц Π² Π½Π°Π½ΠΎΡ€Π°Π·ΠΌΠ΅Ρ€Π½ΠΎΠΌ состоянии. ΠœΠ΅Ρ‚ΠΎΠ΄Ρ‹ исслСдования: гСохимичСскиС ΠΌΠ΅Ρ‚ΠΎΠ΄Ρ‹ поиска ΠΈ Ρ€Π°Π·Π²Π΅Π΄ΠΊΠΈ мСстороТдСний Π½Π΅Ρ„Ρ‚ΠΈ ΠΈ Π³Π°Π·Π°, ΠΏΡ€ΠΎΡΠ²Π΅Ρ‡ΠΈΠ²Π°ΡŽΡ‰Π°Ρ элСктронная микроскопия. Π Π΅Π·ΡƒΠ»ΡŒΡ‚Π°Ρ‚Ρ‹. ΠŸΡ€ΠΎΠ²Π΅Π΄Π΅Π½ ΠΎΠ±Π·ΠΎΡ€ ΠΈ Π°Π½Π°Π»ΠΈΠ· Π»ΠΈΡ‚Π΅Ρ€Π°Ρ‚ΡƒΡ€Ρ‹ Π½Π° Ρ‚Π΅ΠΌΡƒ гСохимичСских ΠΌΠ΅Ρ‚ΠΎΠ΄ΠΎΠ² поисков Π·Π°Π»Π΅ΠΆΠ΅ΠΉ Π½Π΅Ρ„Ρ‚ΠΈ ΠΈ Π³Π°Π·Π°, ΠΏΡ€ΠΎΠ°Π½Π°Π»ΠΈΠ·ΠΈΡ€ΠΎΠ²Π°Π½Ρ‹ закономСрности особСнностСй гСохимичСских ΠΏΠΎΠ»Π΅ΠΉ Π½Π°Π΄ мСстороТдСниями Π½Π΅Ρ„Ρ‚ΠΈ ΠΈ Π³Π°Π·Π° Π—Π°ΠΏΠ°Π΄Π½ΠΎ-Бибирской нСфтСгазоносной ΠΏΡ€ΠΎΠ²ΠΈΠ½Ρ†ΠΈΠΈ. ΠŸΡ€Π΅Π΄Π»ΠΎΠΆΠ΅Π½Π° новая гСохимичСская ΠΌΠ΅Ρ‚ΠΎΠ΄ΠΈΠΊΠ° поисков ΠΈ Ρ€Π°Π·Π²Π΅Π΄ΠΊΠΈ, которая способна Π²Ρ‹ΡΠ²Π»ΡΡ‚ΡŒ ΠΌΠΈΠ½Π΅Ρ€Π°Π»ΡŒΠ½Ρ‹Π΅ Ρ„ΠΎΡ€ΠΌΡ‹ нахоТдСния химичСских элСмСнтов Π² Π½Π°Π½ΠΎΡ€Π°Π·ΠΌΠ΅Ρ€Π½ΠΎΠΌ состоянии Π½Π° ΠΏΡ€ΠΎΡΠ²Π΅Ρ‡ΠΈΠ²Π°ΡŽΡ‰Π΅ΠΌ элСктронном микроскопС, Π² частности Π½Π°Ρ…ΠΎΠ΄ΠΈΡ‚ΡŒ ΠΈ ΠΈΠ΄Π΅Π½Ρ‚ΠΈΡ„ΠΈΡ†ΠΈΡ€ΠΎΠ²Π°Ρ‚ΡŒ ΠΌΠΈΠ³Ρ€Π°Ρ†ΠΈΠΎΠ½Π½Ρ‹Π΅ мСталличСскиС соСдинСния.The relevance of the discussed issue is caused by the necessity to develop the technique for finding and identifying metal compounds migration forms over the boundaries of hydrocarbon deposits on the Earth surface. The existing information on possibility of metal transfer from the level of deposits is often contradictory and it can cast doubt on the possibility of geochemical prospecting of hydrocarbon deposits on the basis of information on metal content in the subsurface horizons. The technique of collection and analysis allows us to study nanoscale metal compounds migrating as a part of gas flow to the Earth surface. It becomes possible to determine the origin of nanoscale metal compounds with the ability to prove the genesis of the deep nature of the substance found on the surface. The main aim of the research is to review and to analyze the existing knowledge on geochemical methods of prospecting for oil and gas; to model a new geochemical method associated with the study of samples on a transmission electron microscope for identifying nanoscale particles. The methods used in the study: geochemistry methods of prospecting and exploration of oil and gas fields, transmission electron microscopy. The results of the research. The authors have reviewed and analyzed the literature on geochemical methods to search for oil and gas deposits and analyzed the patterns of geochemical features and magnetic fields on deposits of the West Siberian oil and gas province. The paper introduces a new prospecting and exploration geochemical and magnetic technique which can help identify nanoscale mineral forms of chemical elements with a transmission electron microscope, in particular find and identify migration metal compounds

    Using Severe Plastic Deformation to Produce Nanostructured Materials with Multifunctional Properties

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    ИспользованиС ΠΏΡ€Π΅Ρ†ΠΈΠ·ΠΈΠΎΠ½Π½Ρ‹Ρ… ΠΌΠ΅Ρ‚ΠΎΠ΄ΠΎΠ² структурного Π°Π½Π°Π»ΠΈΠ·Π° (TEM/HRTEM, 3D APT ΠΈ Π΄Ρ€ΡƒΠ³ΠΈΡ…) ΠΏΠΎΠΊΠ°Π·Π°Π»ΠΎ, Ρ‡Ρ‚ΠΎ Ρ„ΠΎΡ€ΠΌΠΈΡ€ΠΎΠ²Π°Π½ΠΈΠ΅ Ρ€Π°Π·Π½Ρ‹Ρ… Ρ‚ΠΈΠΏΠΎΠ² Π³Ρ€Π°Π½ΠΈΡ† Π·Π΅Ρ€Π΅Π½ Π·Π½Π°Ρ‡ΠΈΡ‚Π΅Π»ΡŒΠ½ΠΎ влияСт Π½Π° мСханичСскиС свойства наноструктурных ΠΌΠ΅Ρ‚Π°Π»Π»ΠΎΠ² ΠΈ сплавов, особСнно Π½Π° Ρ…Ρ€ΡƒΠΏΠΊΠΎΡΡ‚ΡŒ ΠΈ ΠΏΠ»Π°ΡΡ‚ΠΈΡ‡Π½ΠΎΡΡ‚ΡŒ, ΡƒΡΡ‚Π°Π»ΠΎΡΡ‚ΡŒ ΠΈ ΡΠ²Π΅Ρ€Ρ…ΠΏΠ»Π°ΡΡ‚ΠΈΡ‡Π½ΠΎΡΡ‚ΡŒ. Π—Π°Ρ‚Ρ€ΠΎΠ½ΡƒΡ‚Ρ‹ вопросы использования Π·Π΅Ρ€Π½ΠΎΠ³Ρ€Π°Π½ΠΈΡ‡Π½ΠΎΠΉ ΠΈΠ½ΠΆΠ΅Π½Π΅Ρ€ΠΈΠΈ для создания Π½Π°Π½ΠΎΠΌΠ°Ρ‚Π΅Ρ€ΠΈΠ°Π»ΠΎΠ², ΠΎΠ±Π»Π°Π΄Π°ΡŽΡ‰ΠΈΡ… сочСтаниСм высоких мСханичСских ΠΈ Ρ„ΡƒΠ½ΠΊΡ†ΠΈΠΎΠ½Π°Π»ΡŒΠ½Ρ‹Ρ… свойств (коррозионная ΠΈ радиационная ΡΡ‚ΠΎΠΉΠΊΠΎΡΡ‚ΡŒ, ΡΠ»Π΅ΠΊΡ‚Ρ€ΠΎΠΏΡ€ΠΎΠ²ΠΎΠ΄Π½ΠΎΡΡ‚ΡŒ ΠΈ Ρ‚. Π΄.). ΠžΠ±ΡΡƒΠΆΠ΄Π°ΡŽΡ‚ΡΡ физичСская ΠΏΡ€ΠΈΡ€ΠΎΠ΄Π° Π΄Π°Π½Π½Ρ‹Ρ… Π½Π΅ΠΎΠ±Ρ‹Ρ‡Π½Ρ‹Ρ… свойств Π½Π°Π½ΠΎΠΌΠ°Ρ‚Π΅Ρ€ΠΈΠ°Π»ΠΎΠ² ΠΈ ΠΈΡ… ΠΏΡ€ΠΈΠΌΠ΅Π½Π΅Π½ΠΈΠ΅ Π² ΠΈΠ½Π½ΠΎΠ²Π°Ρ†ΠΈΠΎΠ½Π½Ρ‹Ρ… Ρ€Π°Π·Ρ€Π°Π±ΠΎΡ‚ΠΊΠ°Ρ….It has been shown by using the precise methods of structural analysis (TEM/HRTEM, 3D APT and others) that the formation of different types of grain boundaries significantly affects the mechanical properties of nanostructured metals and alloys, especially embrittlement and ductility, fatigue and superplasticity. The issues of using grain boundary engineering to create nanomaterials with socalled multifunctional properties obtaining a combination of high mechanical and functional properties (corrosion and radiation resistance, electrical conductivity, etc.) are considered. The physical nature of these unusual properties of nanomaterials and their application in innovative developments to use in the energy, medicine and engineering sectors is discussed

    Archaeological survey of wooden remains from 16th-19th century Sviyazhsk

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    This article is devoted to the results of an archaeological survey carried out in 2008 on the site of the former faubourg (suburb) of Sviyazhsk town. The survey obtained and analysed useful information about the nature and contents of the cultural layer being revealed by the eroding banks of the Kuibyshev reservoir. The survey represented the first archaeological research carried out in the Sviyazhsk faubourg, and yielded much information on its layout. The remains of approximately 40 wooden constructions (buildings, fences, pavements, etc.) from the second half of the 16th-beginning of the 20th century were uncovered during the excavation. The residential character of the excavated buildings was determined by the presence of furnace remains found on the excavation site. The unified orientation of the household buildings from various layers of the excavation site, dating from the mid-16th up to the 20th century, indicates the street plan of the faubourg, which was more or less maintained throughout its existence. More than half the studied constructions were damaged by fire which accordingly gave rise to the development of the Sviyazhsk faubourg. The finds - 5,374 items in total - included 2,863 ceramic fragments (of which 334 were of traditional Bulgar style); 2,391 leather items (shoes, mittens, quivers, etc.); textiles (wool, homespun linen, felt, willow fibre) and iron goods (knives, scissors, nails, etc.). The numerous finds that emerged from the excavation site reflect the life, craft, farming and trading activities of the population of this medieval town and concurred with other known sources illustrating the life of Sviyazhsk residents as the town waxed and waned in its political importance as a trading post and economic centre of the region

    NANOSTRUCTRAL DESIGN OF METALLIC MATERIALS FOR ENHANCING THEIR MULTIFUNCTIONAL PROPERTIES

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    Nanostructuring of metals and alloys by methods of intensive plastic deformation (IPD) can significantly increase the mechanical and functional properties of materials. It is shown that the use of different modes and routes of IPD processing during the formation of nanostructured metals and alloys significantly affects their mechanical properties, especially brittleness and ductility, fatigue and superplasticity.НаноструктурированиС ΠΌΠ΅Ρ‚Π°Π»Π»ΠΎΠ² ΠΈ сплавов ΠΌΠ΅Ρ‚ΠΎΠ΄Π°ΠΌΠΈ интСнсивной пластичСской Π΄Π΅Ρ„ΠΎΡ€ΠΌΠ°Ρ†ΠΈΠΈ (Π˜ΠŸΠ”) ΠΌΠΎΠΆΠ΅Ρ‚ Π·Π½Π°Ρ‡ΠΈΡ‚Π΅Π»ΡŒΠ½ΠΎΠ³ΠΎ ΠΏΠΎΠ²Ρ‹ΡˆΠ°Ρ‚ΡŒ мСханичСскиС ΠΈ Ρ„ΡƒΠ½ΠΊΡ†ΠΈΠΎΠ½Π°Π»ΡŒΠ½Ρ‹Π΅ свойства ΠΌΠ°Ρ‚Π΅Ρ€ΠΈΠ°Π»ΠΎΠ². Показано, Ρ‡Ρ‚ΠΎ использованиС Ρ€Π°Π·Π½Ρ‹Ρ… Ρ€Π΅ΠΆΠΈΠΌΠΎΠ² ΠΈ ΠΌΠ°Ρ€ΡˆΡ€ΡƒΡ‚ΠΎΠ² Π˜ΠŸΠ” ΠΎΠ±Ρ€Π°Π±ΠΎΡ‚ΠΊΠΈ ΠΏΡ€ΠΈ Ρ„ΠΎΡ€ΠΌΠΈΡ€ΠΎΠ²Π°Π½ΠΈΠΈ наноструктурных ΠΌΠ΅Ρ‚Π°Π»Π»ΠΎΠ² ΠΈ сплавов Π·Π½Π°Ρ‡ΠΈΡ‚Π΅Π»ΡŒΠ½ΠΎ влияСт Π½Π° ΠΈΡ… мСханичСскиС свойства, особСнно, Ρ…Ρ€ΡƒΠΏΠΊΠΎΡΡ‚ΡŒ ΠΈ ΠΏΠ»Π°ΡΡ‚ΠΈΡ‡Π½ΠΎΡΡ‚ΡŒ, ΡƒΡΡ‚Π°Π»ΠΎΡΡ‚ΡŒ ΠΈ ΡΠ²Π΅Ρ€Ρ…ΠΏΠ»Π°ΡΡ‚ΠΈΡ‡Π½ΠΎΡΡ‚ΡŒ.ИсслСдованиС Π±Ρ‹Π»ΠΎ частично ΠΏΠΎΠ΄Π΄Π΅Ρ€ΠΆΠ°Π½ΠΎ ΠœΠΈΠ½ΠΈΡΡ‚Π΅Ρ€ΡΡ‚Π²ΠΎΠΌ Π½Π°ΡƒΠΊΠΈ ΠΈ Π²Ρ‹ΡΡˆΠ΅Π³ΠΎ образования Российской Π€Π΅Π΄Π΅Ρ€Π°Ρ†ΠΈΠΈ Π² Ρ€Π°ΠΌΠΊΠ°Ρ… ΠΏΡ€ΠΎΠ΅ΠΊΡ‚Π° β„–14.586.21.0061 (ΡƒΠ½ΠΈΠΊΠ°Π»ΡŒΠ½Ρ‹ΠΉ ΠΈΠ΄Π΅Π½Ρ‚ΠΈΡ„ΠΈΠΊΠ°Ρ‚ΠΎΡ€ ΠΏΡ€ΠΎΠ΅ΠΊΡ‚Π° RFMEFI58618X0061)

    High-Pressure torsion-Induced Grain Growth in Electrodeposited Nanocrystalline Ni

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    Deformation-induced grain growth has been reported in nanocrystalline (nc) materials under indentation and severe cyclic loading, but not under any other deformation mode. This raises an issue on critical conditions for grain growth in nc materials. This study investigates deformation-induced grain growth in electrodeposited nc Ni during high-pressure torsion (HPT). Our results indicate that high stress and severe plastic deformation are required for inducing grain growth, and the upper limit of grain size is determined by the deformation mode and parameters. Also, texture evolution suggests that grain-boundary-mediated mechanisms played a significant role in accommodating HPT strain

    Microstructural changes and strengthening of austenitic stainless steels during rolling at 473 k

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    The microstructural changes in 304L and 316L austenitic stainless steels during plate rolling with 95% rolling reduction at a temperature of 473 K and their effect on strengthening were studie

    Nanostructures in Ti processed by severe plastic deformation

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    Metals and alloys processed by severe plastic deformation (SPD) can demonstrate superior mechanical properties, which are rendered by their unique defect structures. In this investigation, transmission electron microscopy and x-ray analysis were used to systematically study the defect structures, including grain and subgrain structures, dislocation cells, dislocation distributions, grain boundaries, and the hierarchy of these structural features, in nanostructured Ti produced by a two-step SPD procedure-warm equal channel angular pressing followed by cold rolling. The effects of these defect structures on the mechanical behaviors of nanostructured Ti are discussed

    Influence of severe plastic deformation on the precipitation hardening of a FeSiTi steel

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    The combined strengthening effects of grain refinement and high precipitated volume fraction (~6at.%) on the mechanical properties of FeSiTi alloy subjected to SPD processing prior to aging treatment were investigated by atom probe tomography and scanning transmission electron microscopy. It was shown that the refinement of the microstructure affects the precipitation kinetics and the spatial distribution of the secondary hardening intermetallic phase, which was observed to nucleate heterogeneously on dislocations and sub-grain boundaries. It was revealed that alloys successively subjected to these two strengthening mechanisms exhibit a lower increase in mechanical strength than a simple estimation based on the summation of the two individual strengthening mechanisms
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