Plastic Deformation of Nanostructured Materials

Глезер, А. М.; Козлов, Э. В.; Конева, Н. А.; Попова, Н. А.; Курзина, И. А.

doi:10.1201/9781315111964

Cited by 55 publications

(64 citation statements)

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“…For simplicity, we suppose that the strain value = 0.002 for integral yield strength, σ ∑disy is determined by the strain value = 0.002 with σ y at the first (crystalline) phase. To determine the values of the constant 0 = 0 (k(ε)) in the two-phase model, we use the known experimental values of the HP coefficient ) 002 , 0 ( k for PC single-mode samples with BCC, FCC and HCP CL from Table 1 with small-angle GBs, corresponding to the values of σ 0 , G, the lattice constant a [10], the Burgers vectors of the least possible length b and the respective most realistic sliding systems (see Table 2 [2]), the interaction constant for dislocations α [6,7] and the calculated values of least unit dislocations e L d E , extreme grain sizes d 0 , maximal differences of yield strength Δσ m , Δσ ∑dism , in accordance with (5) in [1] and (5), (6) at T=300 K. The values of k at 0.002   are taken, e.g., for α-Fe, Cu, Ni [6,7], Al [10], Zr, α-Ti [2] within the grain range enclosed in the frames.…”

Section: Hall-petch Law For α-Fe Cu Al Ni α-Ti Zr With Third-phasementioning

confidence: 99%

“…We continue the study of TDE predicted in the one-phase model [2,3] and the closely-packed two-phase model [4] of single-mode PC aggregates, now with third-phase (Cu) particles being present according to the three-phase model with Σdis ( ) subject to (5), (6). The increase in temperature causes the value of G(T) (and that of σ 0 (T)) to decrease, whereas the linear parameters b, d increase, with the same linear coefficient of the temperature expansion [6] (for BCC and FCC materials, also see [10]), then the extreme grain size d ∑0 (ε,T) is shifted to the region of smaller grains, d ∑0 (ε,T)> d ∑0 (ε, ′ ) for > ′ (in the same material phase [1,2]), according to 0 ( , ′ ) = ( ′ ) [11]). It follows from (7) that for T varying in a small range the value of d 0 (ε,T) changes multiplicatively with the factor (α G , α d , , ' ) and a correction due to Cu-particles.…”

Section: Temperature Dependence Of Yield Strength and Extreme Grain Smentioning

confidence: 99%

“…, for m = 3.05, which includes at ε=0,002 the normal [5] and abnormal (e.g., see [6,7] and references therein) Hall-Petch (HP) relations for coarse-grained (CG) and nano-crystalline (NC) grains. Notice that at the purely crystalline phase for a singlemode PC aggregate the value of σ(ε) reaches its flow-stress maximum at an extreme grain of average value d 0 [1],…”

Section: Introductionmentioning

confidence: 99%

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Towards a theory of flow stress in multimodal polycrystalline aggregates. Effects of dispersion hardening

Čevizović

Reshetnyak

Sharkeev

2019

Proceedings of the International Conference on Advanced Materials With Hierarchical Structure for New Technologies and Reliable

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We elaborate the recently introduced theory of flow stress, including yield strength, in polycrystalline materials under quasi-static plastic deformations, thereby extending the case of single-mode aggregates to multimodal ones in the framework of a two-phase model which is characterized by the presence of crystalline and grain-boundary phases. Both analytic and graphic forms of the generalized Hall-Petch relations are obtained for multimodal samples with BCC (αphase Fe), FCC (Cu, Al, Ni) and HCP (α-Ti, Zr) crystalline lattices at T=300K with different values of the grainboundary (second) phase. The case of dispersion hardening due to a natural incorporation into the model of a third phase including additional particles of doping materials is considered. The maximum of yield strength and the respective extremal grain size of samples are shifted by changing both the input from different grain modes and the values at the second and third phases. We study the influence of multimodality and dispersion hardening on the temperaturedimensional effect for yield strength within the range of 150-350K.

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Section: Hall-petch Law For α-Fe Cu Al Ni α-Ti Zr With Third-phasementioning

confidence: 99%

Section: Temperature Dependence Of Yield Strength and Extreme Grain Smentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Towards a theory of flow stress in multimodal polycrystalline aggregates. Effects of dispersion hardening

Čevizović

Reshetnyak

Sharkeev

2019

Proceedings of the International Conference on Advanced Materials With Hierarchical Structure for New Technologies and Reliable

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“…For a cubic CL, an isotropic distribution of crystallites in a PC sample implies that the crystallographic slip planes relative to the loading z-axis are situated inside the angle   4 4 ,    , so that averaging, with respect to all directions, of the texture factor = ( , , ) leads to ̅ = 1 √2 ⁄ [3,5]. From (6), (7) it follows that:…”

Section: Two-level System For a Derivation Of The Scalar Density Of Dmentioning

confidence: 99%

“…The values of k(ε) at 0.002   chosen, e.g. for α-Fe, Cu, Ni [6,7], Al [10], Zr, α-Ti [2,8,9] within the grain range enclosed in the frames and the .value of α for Zr approximately equal to 0.5. Table 1) extreme grain size values d ρ .…”

Section: Two-level System For a Derivation Of The Scalar Density Of Dmentioning

confidence: 99%

On combined quantized and mechanical descriptions of the Chernov-Luders macroband of localized deformation

Reshetnyak

Shilko

Sharkeev

2019

Proceedings of the International Conference on Advanced Materials With Hierarchical Structure for New Technologies and Reliable

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We suggest a quantum procedure, based on our recent statistical theory of flow stress in polycrystalline materials under quasi-static plastic deformations, with the intention to approach a theoretical description of the Chernov-Lüders shear macroband of localized deformation, exhibited by some Fe-containing materials with a second phase beyond the yield-strength point on the stress-strain curve σ=σ(ε). The procedure makes substantial use of a quasi-particle interpretation for the minimal portion of mechanical energy in a given single-mode polycrystalline aggregate that is necessary for the thermal-fluctuation mechanism to create a 0D-defect nanopore as the initial zone of a localized deformation under external loading. Using a quasi-particle description, we obtain analytic expressions both for the scalar density of dislocations, given the size of grains, the temperature, the most probable sliding system, and for the dependence σ=σ(ε) itself. A two-level system, which characterizes the mechanism of absorption and emission of such quasi-particles (dislocons) by the crystal lattice of any grain under quasi-static loading provides an effective physical description for the emergence and propagation of the Chernov-Lüders shear macroband. An enhancement of acoustic emission observed in experiments and accompanied by the macroband phenomenon justifies the interpretation of a dislocon as a composite short-lived particle consisting of acoustic phonons. A more realistic three-level system within a two-phase model with third (with dispersion particles) phase presence for actual polycrystalline samples is also proposed.

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Microstructure and Crystallographic Texture of Silicon Iron Modified by Torsion Under Quasihydrostatic Pressure

et al. 2019

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The electron backscatter diffraction, X-ray diffraction analysis, electromotive force instantaneous measurement, microhardness and coercive force measurement techniques are used to explore the development of the microstructure, crystallographic texture and physico-mechanical properties of silicon iron (Fe-3% Si) alloy under quasi-hydrostatic pressure in a Bridgman anvil. It is found that the alloy deformation is accompanied by its significant hardening. In-plane torsion test shows that the average grain size rapidly decreases down to 185 nm after a quater turn of the movable anvil. With the number of turns increased up to six the grain size gradually decreases down to 150 nm. At the same time, the average size of subgrains is less dependent on the deformation degree. The crystallographic texture evolution involves the formation of the strong {001} <110> texture component after comparatively small megaplastic deformation followed by the simple shear texture formation. Such a behavior can be correctly described in terms of non-equilibrium thermodynamics.

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Plastic Deformation of Nanostructured Materials

Cited by 55 publications

References 0 publications

Towards a theory of flow stress in multimodal polycrystalline aggregates. Effects of dispersion hardening

Towards a theory of flow stress in multimodal polycrystalline aggregates. Effects of dispersion hardening

On combined quantized and mechanical descriptions of the Chernov-Luders macroband of localized deformation

Microstructure and Crystallographic Texture of Silicon Iron Modified by Torsion Under Quasihydrostatic Pressure

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