Compressive deformation of Fe nanopillar at high strain rate: Modalities of dislocation dynamics

Dutta, Ashudeb

doi:10.1016/j.actamat.2016.11.062

Cited by 36 publications

(27 citation statements)

References 55 publications

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“…8(e) and 8(f)). The formation of <100> dislocation has also been observed during the compressive de- formation of <100> BCC Fe nanopillars 20 . Generally, it is assumed that <100> dislocation is highly stable and immobile and aids in the nucleation of micro-cracks in BCC metals.…”

Section: Dislocation Multiplication Mechanism and Dissociation Of mentioning

confidence: 87%

“…However, with increasing strain, the edge components escape to the surface due to higher mobility and this leads to the accumulation of straight screw dislocations in <110> BCC Fe nanowires 19 . During compressive deformation of <100> BCC Fe nanowires, it has been shown that dislocationmediated plasticity dominates at 500 K, whereas the twinning mechanism has been observed in addition to the dislocation slip at lower temperatures 20 . A similar behavior has been observed with respect to temperature in <110> BCC Fe nanowires 10 .…”

Section: Introductionmentioning

confidence: 99%

“…Most of these studies in BCC metallic nanowires have been focused mainly on deformation aspects such as twinning and dislocation behavior [8][9][10][11][12][13][14][15][16][17][18][19][20] . It is surprising that enough attention has not been paid towards the fracture behavior of BCC Fe nanowires.…”

Section: Introductionmentioning

confidence: 99%

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Atomistic simulations on ductile-brittle transition in ⟨111⟩ BCC Fe nanowires

Sainath

Choudhary

2017

Journal of Applied Physics

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Molecular dynamics simulations have been performed to understand the influence of temperature on the tensile deformation and fracture behavior of <111> BCC Fe nanowires. The simulations have been carried out at different temperatures in the range 10-1000 K employing a constant strain rate of 1× 10 8 s −1 . The results indicate that at low temperatures (10-375 K), the nanowires yield through the nucleation of a sharp crack and fails in brittle manner. On the other hand, nucleation of multiple 1/2<111> dislocations at yielding followed by significant plastic deformation leading to ductile failure has been observed at high temperatures in the range 450-1000 K. At the intermediate temperature of 400 K, the nanowire yields through nucleation of crack associated with many mobile 1/2<111> and immobile <100> dislocations at the crack tip and fails in ductile manner. The ductile-brittle transition observed in <111> BCC Fe nanowires is appropriately reflected in the stress-strain behavior and plastic strain at failure. The ductile-brittle transition increases with increasing nanowire size. The change in fracture behavior has been discussed in terms of the relative variations in yield and fracture stresses and change in slip behavior with respect to temperature. Further, the dislocation multiplication mechanism assisted by the kink nucleation from the nanowire surface observed at high temperatures has been presented.

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Section: Dislocation Multiplication Mechanism and Dissociation Of mentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

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Atomistic simulations on ductile-brittle transition in ⟨111⟩ BCC Fe nanowires

Sainath

Choudhary

2017

Journal of Applied Physics

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“…Nanosized crystals of bcc metals are a classical object of MD simulation [7][8][9][10][11][12][13]. Currently, considerable attention is paid to metals with a bcc lattice [14][15][16][17][18][19][20]. From a physical point of view, bcc metals are more interesting because they provide a greater variety of atomic rearrangements, governing the strength.…”

Section: Introductionmentioning

confidence: 99%

“…In this connection, the appearance of direct experimental data on the strength of bcc nanocrystals substantially facilitated the problem of selection and verification of these potentials. A great number of works on MD-simulation enabled to predict the key effects controlling the level of strength of nanosized nanocrystals, namely: (i) the size effect, (ii) dependence of strength on orientation, (iii) the temperature dependence of strength, and (iv) dependence of strength on the stress state mode [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. At the same time, the absence of a completed theory of strength of nanosized crystals is a characteristic feature of science of the strength of these objects.…”

Section: Introductionmentioning

confidence: 99%

Atomic Mechanisms Governing Strength of Metallic Nanosized Crystals

Котречко¹,

Ovsijannikov²,

Mikhaĭlovskij³

et al. 2018

Molecular Dynamics

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Fundamentals of the atomic mechanisms governing the strength of nanosized metallic crystals are described. An attempt is made to explain on this basis the size and orientation effects, temperature dependence of strength and atomism of fracture of bcc crystals under triaxial uniform (hydrostatic) tension. A feature of the proposed material is that it combines the results of molecular dynamics simulation with the data of experimental research findings on failure of metallic nanosized crystals under the high-field mechanical loading. It is exhibited that local instability of the lattice is the main mechanism governing the strength of defect-free nanosized crystals (NSC). Based on the concept of local instability, an explanation is given of the nature of the size effect in NSC, as well as of the differences in its manifestation in nanocrystals with bcc and fcc lattices. The concept of the mechanism of thermal activation of local instability is outlined. This enables to explain the specific features of the temperature dependence of NSC. The results of experimental studies and molecular dynamics simulation of the failure of tungsten nanocrystals under hydrostatic tension are presented. The ideas about the atomism of the bcc-fcc transition in these conditions are articulated.

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A Glimpse of the Growth of Mechanical Metallurgy Over the Past 50 years

Ray

2023

Indian Institute of Metals Series

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Compressive deformation of Fe nanopillar at high strain rate: Modalities of dislocation dynamics

Cited by 36 publications

References 55 publications

Atomistic simulations on ductile-brittle transition in ⟨111⟩ BCC Fe nanowires

Atomistic simulations on ductile-brittle transition in ⟨111⟩ BCC Fe nanowires

Atomic Mechanisms Governing Strength of Metallic Nanosized Crystals

A Glimpse of the Growth of Mechanical Metallurgy Over the Past 50 years

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