Nucleation‐Controlled Plasticity of Metallic Nanowires and Nanoparticles

Mordehai, Dan; David, Omer; Kositski, Roman

doi:10.1002/adma.201706710

Cited by 35 publications

(25 citation statements)

References 128 publications

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“…12(a)]. In such regimes, where R < 1, homogeneously nucleated dislocations are free to self-organize under the influence of long-range elastic forces [25,68] and the formation of a shear band only mildly affects global dislocation dynamics. The value of the exponent τ ∼ 1 presents a signature of archetypically "wild" plasticity in the sense of Ref.…”

Section: Avalanche Statisticsmentioning

confidence: 99%

“…The mechanical response to monotone loading carries a memory of the initial state and in our tests, the preparation was entirely dislocation-free, as the goal was to simulate the plastic deformation of ultrasmall systems (nanoparticles and nanopillars) [24,25]. To obtain the generic response, one can prime the crystal by subjecting it to cyclic protocol.…”

Section: Cyclic Loadingmentioning

confidence: 99%

“…where A is a standard fourth-order tensor with constant entries. Substituting the expression for ζ into the compatibility equations (25) we obtain h + A[ξ − (d + g)] = KBξ, where B is another standard forth order tensor; the explicit expressions for the tensors A and B can be found in Ref. [94].…”

Section: Compatible Disordermentioning

confidence: 99%

“…Moreover, even though plasticity at macroscale is generally associated with ductility, crystal plasticity at submicron scales exhibits major stress drops or strain bursts reminiscent of brittle fracture [5,[19][20][21][22]. Brittleness, usually attributed to dislocation-free crystals [23], reappears in nanoparticles and nanopillars that seem to be "breaking plastically" by generating a large number of globally correlated dislocations [24,25]. The implied system-size events hinder our ability to control plastic deformation at submicron scale and compromise the reliable functioning of ultra-small machinery [10,11,[26][27][28].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Variety of scaling behaviors in nanocrystalline plasticity

Zhang

Salman²,

Weiss

et al. 2020

Phys. Rev. E

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We address the question of why larger, high-symmetry crystals are mostly weak, ductile, and statistically subcritical, while smaller crystals with the same symmetry are strong, brittle and supercritical. We link it to another question of why intermittent elasto-plastic deformation of submicron crystals features highly unusual size sensitivity of scaling exponents. We use a minimal integer-valued automaton model of crystal plasticity to show that with growing variance of quenched disorder, which can serve in this case as a proxy for increasing size, submicron crystals undergo a crossover from spin-glass marginality to criticality characterizing the second order brittle-to-ductile (BD) transition. We argue that this crossover is behind the nonuniversality of scaling exponents observed in physical and numerical experiments. The nonuniversality emerges only if the quenched disorder is elastically incompatible, and it disappears if the disorder is compatible.

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Section: Avalanche Statisticsmentioning

confidence: 99%

Section: Cyclic Loadingmentioning

confidence: 99%

Section: Compatible Disordermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Variety of scaling behaviors in nanocrystalline plasticity

Zhang

Salman²,

Weiss

et al. 2020

Phys. Rev. E

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show abstract

“…Interestingly, this exhaustion stage is associated with slight increase in flow stress (Figure 1). Since the deformation in nanowires is nucleation controlled [23], decrease in dislocation density indicates that the rate of exhaustion or annihilation is higher than the nucleation. Following dislocation exhaustion stage, dislocation density remains very low and constant with marginal fluctuations around a mean value (Figure 1).…”

Section: Simulation Detailsmentioning

confidence: 99%

Effect of size, temperature and strain rate on dislocation density and deformation mechanisms in Cu nanowires

Rohith

Sainath

Srinivasan

2019

Physica B: Condensed Matter

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In the present study, molecular dynamics (MD) simulations have been performed to understand the effect of nanowire size, temperature and strain rate on the variations in dislocation density and deformation mechanisms in <100> Cu nanowires. The nanowire size has been varied in the range 1.446-43.38 nm with a constant length of 21.69 nm. Different temperatures varying from 10 K to 700 K and strain rates in the range of 5 × 10 7 -1 × 10 9 s −1 have been considered. For all the conditions, the variations in dislocation density (ρ) has been calculated as a function of strain. The results indicate that the variations in dislocation density exhibits two stages irrespective of the conditions: (i) dislocation exhaustion at small strains followed by (ii) dislocation starvation at high strains. However, with decreasing size and increasing temperature, the rate of dislocation exhaustion increases, which results in early transition from dislocation exhaustion stage to dislocation starvation stage. Similarly, with increasing strain rate, the rate of dislocation exhaustion and also the transition strain increases.

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In situ Observation of Structural Evolution and Phase Engineering of Amorphous Materials during Crystal Nucleation

Han

et al. 2022

Advanced Materials

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The nucleation pathway determines the structures and thus properties of formed nanomaterials, which is governed by the free energy of the intermediate phase during nucleation. The amorphous structure, as one of the intermediate phases during nucleation, plays an important role in modulating the nucleation pathway. However, the process and mechanism of crystal nucleation from amorphous structures still need to be fully investigated. Here, in situ aberration‐corrected high‐angle annular dark‐field scanning transmission electron microscopy (HAADF‐STEM) is employed to conduct real‐time imaging of the nucleation of ultrathin amorphous nanosheets (NSs). The results indicate that their nucleation contains three distinct stages, i.e., aggregation of atoms, crystallization to form lattice‐expanded nanocrystals, and relaxation of the lattice‐expanded nanocrystals to form final nanocrystals. In particular, the crystallization processes of various amorphous materials are investigated systematically to form corresponding nanocrystals with unconventional crystalline phases, including face‐centered‐cubic (fcc) Ru, hexagonal‐close‐packed (hcp) Rh, and a new intermetallic IrCo alloy. In situ electron energy‐loss spectroscopy (EELS) analysis unveils that the doped carbon in the original amorphous NSs can migrate to the surface during the nucleation process, stabilizing the obtained unconventional crystal phases transformed from the amorphous structures, which is also proven by density functional theory (DFT) calculations.

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Nucleation‐Controlled Plasticity of Metallic Nanowires and Nanoparticles

Cited by 35 publications

References 128 publications

Variety of scaling behaviors in nanocrystalline plasticity

Variety of scaling behaviors in nanocrystalline plasticity

Effect of size, temperature and strain rate on dislocation density and deformation mechanisms in Cu nanowires

In situ Observation of Structural Evolution and Phase Engineering of Amorphous Materials during Crystal Nucleation

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