Review: Modes and Processes of Severe Plastic Deformation

Segal, V. M.

doi:10.20944/preprints201807.0050.v1

Cited by 32 publications

(10 citation statements)

References 52 publications

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“…For the annealed nanopowders, the value of Qs3 was ~2-3 kTm less than the one for the mechanically activated nanopowders. The calculated values of the SPS activation energy correspond well to the activation energy of heterodiffusion of the tungsten atoms in the -phase (taking into account the corrections for the decrease in the activation energy of the grain boundary diffusion in the fine-grained materials [65]). Available data on sintering activation energies of W-Ni-Fe tungsten alloys give dramatically different values; Qs for W-8.4Ni-3.6Fe alloy is 250 kJ/mol according to [66], whereas reference [67] gives Qs = 367 kJ/mol for W-8.4Ni-3.6Fe alloy and 480 kJ/mol for 95W-3Ni-2Fe.…”

Section: Discussionsupporting

confidence: 53%

“…In the course of HEBM, the grinding of the -phase particles with the FCC lattice is difficult due to high ductility of these ones. In the course of HEBM, the grinding of the -phase particles and the accumulation of the OMDs at the grain boundaries take place [65]. The diffusion permeability of the -phase grain boundaries after HEBM appears to be higher than the one of "conventional" grain boundaries in the -phase formed during sintering individual phase particles to each other.…”

Section: Discussionmentioning

confidence: 99%

“…According to the theory of the nonequilibrium grain boundaries [65], the increasing of the free (excess) volume of the grain boundaries α is the origin of the decrease in the activation energy of the grain boundary diffusion in the strongly deformed fine-grained metals and alloys. The magnitude of α is proportional to the density of orientation mismatch dislocations (OMDs) captured by the grain boundaries during severe plastic deformation.…”

Section: Discussionmentioning

confidence: 99%

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Effect of High Energy Ball Milling Time on the Density and Mechanical Properties of W-7%Ni-3%Fe Alloy

Нохрин¹,

Малехонова²,

Чувильдеев³

et al. 2023

Preprint

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The present work was aimed at the investigation of effect of High Energy Ball Milling (HEBM) time on the sintering kinetics, structure, and properties of heavy tungsten alloy (HTA) W-7%Ni-3%Fe. The HTA samples were obtained from the nanopowders (20-80 nm) by conventional liquid phase sintering (LPS) in hydrogen and by Spark Plasma Sintering (SPS) in vacuum. The HTA density was shown to depend on the HEBM time non-monotonously that originates from the formation of non-equilibrium solid solutions in the W-Ni-Fe systems during HEBM. The SPS kinetics of the HTA nanopowders was shown to have a two-stage character, the intensity of which depends on the Coble diffusion creep rate and on the intensity of diffusion of the tungsten atoms in the crystal lattice of the -phase. The kinetics of sintering of the initial submicron powders have a single-stage character originating from the intensity of the grain boundary diffusion in the -phase. The dependencies of the hardness and of the yield strength on the grain sizes were found to obey the Hall-Petch relation. The hardness, strength, and dynamic strength in the compression tests of the fine-grained tungsten alloys obtained by SPS and LPS were studied.

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Section: Discussionsupporting

confidence: 53%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Effect of High Energy Ball Milling Time on the Density and Mechanical Properties of W-7%Ni-3%Fe Alloy

Нохрин¹,

Малехонова²,

Чувильдеев³

et al. 2023

Preprint

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“…Continuous pressing was first proposed by Segal et al (34) as a continuous simple shear process of long rods based on the famous Conform process. The ECAP with a Conform (ECAP-C) procedure was first developed and used for grain refinement in commercially pure aluminum down to 650 nm (35).…”

Section: Continuous Equal-channel Angular Pressingmentioning

confidence: 99%

Using Severe Plastic Deformation to Produce Nanostructured Materials with Superior Properties

Valiev

Straumal

Langdon

2022

Annu. Rev. Mater. Res.

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The past decade was marked by significant advances in the development of severe plastic deformation (SPD) techniques to achieve new and superior properties in various materials. This review examines the achievements in these areas of study and explores promising trends in further research and development. SPD processing provides strong grain refinement at the nanoscale and produces very high dislocation and point defect densities as well as unusual phase transformations associated with particle dissolution, precipitation, or amorphization. Such SPD-induced nanostructural features strongly influence deformation and transport mechanisms and can substantially enhance the performance of advanced materials. Exploiting this knowledge, we discuss the concept of nanostructural design of metals and alloys for multifunctional properties such as high strength and electrical conductivity, superplasticity, increased radiation, and corrosion tolerance. Special emphasis is placed on advanced metallic biomaterials that promote innovative applications in medicine.

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“…In recent decades, there has been a growing interest in ultrafine-grained (UFG) materials obtained with severe plastic deformation (SPD). [1][2][3] The SPD processes provide for an accumulation of high-degree deformation, which contributes to the formation of high-angle grain boundaries. [4][5][6] UFG materials are characterized by an increased complexity of mechanical, physical and operational characteristics.…”

Section: Introductionmentioning

confidence: 99%

ECAP-treated aluminium alloy AA2030: microstructure and mechanical properties

Andreyachshenko¹,

Isheva²,

Mazhit³

et al. 2019

Mater. Tehnol.

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The work deals with the effect of the ECAP treatment on the microstructure and mechanical properties of the AA2030 alloy. There were four cycles of deformation in the 105°-tool for pre-annealed samples, which ensured the preparation of an ultrafine-grained structure, both along the Bc route and along the C route. The average grain size after four cycles of ECAP was 420 nm for the samples treated along the Bc route and 380 nm for the samples treated along the C route. In the structure of the metal, there were inclusions of Al20Cu2Mn3, the q-phase and Al7Cu3Fe. After three cycles of the ECAP treatment, the alloy was hardened by 54 % along the Bc route and 60 % along the C route compared with the annealed condition. The overall increase in the microhardness was 138 % for the samples treated along the Bc route and 113 % for the samples treated along the C route. Because of prolonged aging, the number of dispersoids increased at room temperature, long rod-like inclusions transformed into more favourable short ones with a length of up to 150 nm, and partial dissolution of the q-phase was observed. After the aging, the grain boundaries were predominantly equilibrium, thin, without the moire contrast, and a rearrangement of dislocation walls into subgrain boundaries was found. In addition, after the prolonged natural aging, large grains with non-equilibrium boundaries fragmented into subgrains with sizes of 100-300 nm.

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Review: Modes and Processes of Severe Plastic Deformation

Cited by 32 publications

References 52 publications

Effect of High Energy Ball Milling Time on the Density and Mechanical Properties of W-7%Ni-3%Fe Alloy

Effect of High Energy Ball Milling Time on the Density and Mechanical Properties of W-7%Ni-3%Fe Alloy

Using Severe Plastic Deformation to Produce Nanostructured Materials with Superior Properties

ECAP-treated aluminium alloy AA2030: microstructure and mechanical properties

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