Influence of the relaxation processes on the structure formation in pure metals and alloys under high-pressure torsion

Degtyarev, M. V.; Чащухина, Т. И.; Воронова, Л. М.; Пацелов, А. М.; Pilyugin, V. P.

doi:10.1016/j.actamat.2007.04.017

Cited by 105 publications

(71 citation statements)

References 25 publications

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“…The true strain was calculated taking into account the shear components of the deformation and upsetting, which depended on a distance to the sample center. The calculation method is described in detail in [5]. The true strain at a distance of 1.5 mm from the center of a sample was е = 8.…”

Section: Methodsmentioning

confidence: 99%

“…The structure of iron during severe plastic deformation, in particular, in Bridgman anvils, develops stage-by-stage [5,6]. Firstly, the structure of a cellular type is formed; then individual microcrystallites (regions surrounded by highangle boundaries [7]) appear with increasing true strain, resulting in the formation of a mixed structure; and finally, the material transits into a submicrocrystalline state.…”

Section: Introductionmentioning

confidence: 99%

“…But only in a few of them the change of the crystallographic texture is analyzed [5,10,12]. According to X-ray studies in pure iron, most of the elements at the stage of the mixed structure has been established to possess an {101} orientation, whereas the material at the stage of the SMC structure transits into a textureless state [5]. Data received by means of electron back-scatter diffraction (EBSD) give an evidence that the final texture obtained by HPT is {110} being parallel to the disc [12].…”

Section: Introductionmentioning

confidence: 99%

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Effect of microcrystallites formed by deformation on the growth and orientation of grains during recrystallization of iron

Воронова¹,

Degtyarev²,

Чащухина³

et al. 2017

LoM

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Changes of an ultradispersed structure in deformed iron after annealing have been studied. Ultradispersed structures of two different types, cellular and submicrocrystalline (SMC) ones, have been formed in iron by high pressure torsion deformation. The effect of the deformation structure type on the temperature of recrystallization onset, the size of recrystallized grains, and the recrystallization texture has been explored. A comparison of recrystallization of the initial cellular and SMC structures should be made to determine the role of microcrystallites. The recrystallization temperature of iron with an SMC structure is 200 to 250°С lower than that of iron with a cellular structure because of the presence of microcrystallites, which are ready recrystallization nuclei. The recrystallization (annealing at 750°C, 1h) of the cellular structure results in the formation of a coarse-grained structure with an average recrystallized grain size that is by an order of magnitude larger than that after the same annealing of the SMC structure (5 and 180 μm, respectively). The significantly different feature of the SMC structure in contrast to the cellular one is the annealing-assisted formation of a <110> recrystallization texture in it, whereas the annealing of iron with the cellular structure does not cause the formation of a recrystallization macrotexture. An increase in the sharpness of the recrystallization texture correlates with a decrease in the average grain-boundary misorientation angle.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of microcrystallites formed by deformation on the growth and orientation of grains during recrystallization of iron

Воронова¹,

Degtyarev²,

Чащухина³

et al. 2017

LoM

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“…Дисковые образцы указанных металлов имели исходную толщину 0,25-0,35 мм и диаметр, соответствующий рабочим площадкам пуансонов наковален. Структурные измере-ния проводили методами металлографии, просвечивающей и сканирующей электронной микроскопии на ПЭМ JEM-200 CX и СЭМ Quanta-200 Pegasus, измерение микротвёрдости проводили на приборе ПМТ-3 [6]. Увеличение давления приводило к возрастанию неопреде-ленности его значений вследствие ряда аппаратурных эффектов, например упругопластиче-ской деформации, как образцов, так и пуансонов.…”

Section: материалы и методикаunclassified

“…Существенно более высокие величины давлений дости-жимы только в ударно-волновых методах обработки, однако последние имеют ограничение по степени макродеформации. Известно, что давление пластифицирует материалы, позволяя получать большие деформации и вследствие этого субмикро-и наноструктурные состояния [4][5][6][7]. Это оказывает влияние на структурно-чувствительные фундаментальные и служебные свойства: фазовую стабильность, прочность, характер разрушения, трение и износ, тепло-и электропроводность и т. д.…”

Section: Introductionunclassified

Effect of severe deformation on the structure, fracture pattern and mechanical properties of refractory metals

Pilyugin¹,

Gapontseva²,

Tolmachev³

et al. 2017

DREAM

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High-pressure torsion is a method enabling one to obtain high strains without destroying the material being processed and to form the submicro-and nanocrystalline states in it. In this paper, this technique serves to process some brittle refractory metals. Particularly, the effect of pressure on the plasticity of brittle refractory metals strained by high pressure torsion using Bridgman anvils is studied. Namely, the critical pressure required for the realization of severe plastic deformation of refractory metals without destroying it by high pressure torsion is established. This value of the deformation pressure is estimated as 0.05 of the bulk modulus or 0.015 of the shear modulus of each metal. It has been established that the structural transformations of brittle metals caused by high pressure torsion forming the submicro-and nanocrystalline states have a significant effect on the mechanical properties of the metals as leading to significant work hardening. Moreover, with increasing strain (the number of anvil rotations), the mechanism of the fracture of the samples changes from cleavage to quasi-ductile one on the boundaries of the crystallites. Physical Review, 1935, vol. 48, pp. 825-847. 4. KeywordsPilyugin V.P., Voronova L.M., Degtyarev M.V., Chashchukhina T.I., Vykhodets V.B., Kurennykh T.E. Structure evolution of pure iron upon low-temperature deformation under high pressure. The Physics of Metals and Metallography, 2010, vol. 110, no. 6, pp. 564-573. DOI: 10.1134/S0031918X10120070 5.Pilyugin V.P., Gapontseva T.M., Chashchukhina T.I., Voronova L.M., Shchinova L.I., Degtyarev M.V. Evolution of the structure and hardness of nickel upon cold and low-temperature deformation under pressure. The Physics of Metals and Metallography, 2008, vol. 105, no. 4, pp. 409-419. DOI: 10.1134/S0031918X08040157 6. Degtyarev M.V., Chashchukhina T.I., Voronova L.M., Patselov A.M., Pilyugin V.P. Influence of the relaxation processes on the structure formation in pure metals and alloys under high-pressure torsion.

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Principles and Technical Parameters of High‐Pressure Torsion

Valiev¹,

Zhilyaev²,

Langdon³

2013

Bulk Nanostructured Materials

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Influence of the relaxation processes on the structure formation in pure metals and alloys under high-pressure torsion

Cited by 105 publications

References 25 publications

Effect of microcrystallites formed by deformation on the growth and orientation of grains during recrystallization of iron

Effect of microcrystallites formed by deformation on the growth and orientation of grains during recrystallization of iron

Effect of severe deformation on the structure, fracture pattern and mechanical properties of refractory metals

Principles and Technical Parameters of High‐Pressure Torsion

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