A Physical Model for the Initial Stages of the Fragmentation of Polycrystals in the Process of Developed Plastic Deformation

Рыбин, В. В.; Перевезенцев, В. Н.; Svirina, Yu. V.

doi:10.1134/s0031918x17120110

Cited by 13 publications

(6 citation statements)

References 10 publications

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“…We consider this process in view of the following evolution scenario. While a fragmented structure is exposed to deformation, local zones unable for the further evolution (a so-called critical structure) develop in it [ 36 ]. The research on this phenomenon has pointed out that microcracks open along certain boundaries and may stop near particular joints [ 36 , 37 ].…”

Section: Resultsmentioning

confidence: 99%

“…While a fragmented structure is exposed to deformation, local zones unable for the further evolution (a so-called critical structure) develop in it [ 36 ]. The research on this phenomenon has pointed out that microcracks open along certain boundaries and may stop near particular joints [ 36 , 37 ]. As a rule, these boundaries represent boundaries with a significant plastic displacement of neighboring regions in a crystal (above 15–20 degrees), i.e., the rotational instability as detaching disclinations develop in such zones of a sample under deformation.…”

Section: Resultsmentioning

confidence: 99%

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Fatigue-Induced Evolution of AISI 310S Steel Microstructure after Electron Beam Treatment

et al. 2020

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Research was carried out to explore the effect of pulsed electron beam irradiation on the behavior of structure and phase state in AISI 310S steel exposed to high-cycle fatigue. A 2.2 times increase in the fatigue life of samples irradiated by electron beams was revealed. The outcomes of scanning and transmission electron microscopic studies suggest the most probable reason for the fracture of steel samples irradiated by a high-intensity electron beam to be microcraters originating on a treated surface and acting as stress risers initiating the propagation of microcracks. The irradiation with a pulsed electron beam causes extremely fast melting of the surface. As a result of the subsequent rapid crystallization, a polycrystalline structure nearly twice as small as an average grain in the untreated steel is formed. Since a surface layer crystallizes rapidly, crystallization cells ranging from 120 to 170 nm develop in the volume of grains. The fatigue testing is shown to be associated with a martensite transformation γ ⇒ ε in the surface layer. One option to intensify a fatigue life increase of the steel in focus is supposed to be the neutralization of crater-forming on a surface treated by electron beams.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Fatigue-Induced Evolution of AISI 310S Steel Microstructure after Electron Beam Treatment

et al. 2020

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“…As the true strain accumulated to 4.5, the thickness of the stripes decreased to 1÷2 µm, while only a small part of the microstripes acquired high-angle misorientations, and the random cell boundaries remained the same low-angle. In works [10,25], where other monotonic deformation processes were used, in particular, drawing, the boundaries of stripes in various metals formed by the movements of partial disclinations are called boundaries of deformation origin. These boundaries, like the boundaries of the stripes after rolling, acquired a morphology close to rectilinear and are directed along the drawing of the material.…”

Section: Mechanics and Mesomechanics Of Rollingmentioning

confidence: 99%

Rational Methods of Plastic Deformation Providing Formation of Ultrafine-Grained Structure in Large-Sized Products

Utyashev,

Botkin,

Volkova

et al. 2024

Rev. Adv. Mater. Technol.

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Based on the peculiarities of plastic deformation mechanics and physical mesomechanics, the processes are considered and technological schemes for their realization are proposed to ensure the formation of ultrafine-grained structure in axisymmetric products of large sizes. Deformation of coarse-grained materials in temperature-velocity conditions of superplastic deformation and methods of severe plastic deformation are taken as methods of preparation of such a structure. All of these deformations include large strain, and they are carried out at low hydraulic press speeds, but at different temperatures: in the mode of superplasticity at hot temperatures, and in the mode of severe plastic deformation at warm or cold temperature deformation. The first mode allows grains to be refined to microcrystalline sizes of 1–10 microns, and such a material acquires the ability to deform in a state of superplasticity, i.e., in tension with low resistance to deformation and high elongation. The second mode (severe plastic deformation) refines grains to submicro- (1÷0.1 µm) and nanosizes (less than 0.1 µm), thus giving metal materials record structural strength, as well as the possibility to use processing in extended temperature-velocity conditions of superplastic deformation in comparison with microcrystalline structure.

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“…In the course of deformation, the misorientation of cell blocks increases so that partial disclinations begin to form and move, which leads to the rotation of adjacent grain regions and the formation of new grain boundaries. Thus, the subdivision of original grains into smaller highly misoriented fragments occurs [14,113,116].…”

Section: Description Of the Aspects (Conditions) Original And Modifie...mentioning

confidence: 99%

“…At low homologous temperatures, grain refinement takes place, which will be considered in this paper. By grain refinement (fragmentation), we mean the process of separating grains into fragments (grain integrity at the mesolevel is kept unchanged), triggered by the progressive increase in the misorientation of fragments during plastic deformation, implemented due to dislocation-disclination mechanisms [13][14][15]. The description of polycrystal grain refinement induced by severe plastic deformation is important because grain size significantly affects the effective properties of the material.…”

Section: Introductionmentioning

confidence: 99%

Advanced Statistical Crystal Plasticity Model: Description of Copper Grain Structure Refinement during Equal Channel Angular Pressing

Romanov

Shveykin

Трусов

2023

Metals

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The grain structure of metals changes significantly during severe plastic deformation (SPD), and grain refinement is the main process associated with SPD at low homologous temperatures. Products made of ultrafine-grained materials exhibit improved performance characteristics and are of considerable industrial interest, which generates a need for the creation of comprehensive grain refinement models. This paper considers the integration of the ETMB (Y. Estrin, L.S. Toth, A. Molinari, Y. Brechet) model, which describes the evolution of an average cell size during deformation into the two-level statistical crystal plasticity constitutive model (CM) of FCC polycrystals. The original relations of the ETMB model and some of its modifications known from the literature were analyzed to obtain an accurate, physically admissible description of the grain refinement process. The characteristics of the grain substructure determined with the framework of the advanced ETMB model were taken into account in the CM in a hardening formula. By applying the CM with the integrated ETMB model, numerical experiments were performed to simulate the changes in the grain structure of copper during equal channel angular pressing (ECAP) at room temperature. The results obtained are in good agreement with the experimental data. The ideas about further development of the proposed model are outlined.

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A Physical Model for the Initial Stages of the Fragmentation of Polycrystals in the Process of Developed Plastic Deformation

Cited by 13 publications

References 10 publications

Fatigue-Induced Evolution of AISI 310S Steel Microstructure after Electron Beam Treatment

Fatigue-Induced Evolution of AISI 310S Steel Microstructure after Electron Beam Treatment

Rational Methods of Plastic Deformation Providing Formation of Ultrafine-Grained Structure in Large-Sized Products

Advanced Statistical Crystal Plasticity Model: Description of Copper Grain Structure Refinement during Equal Channel Angular Pressing

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