Dynamic Plasticity and Failure of Microscale Glass: Rate-Dependent Ductile–Brittle–Ductile Transition

Ramachandramoorthy, Rajaprakash; Schwiedrzik, Jakob; Pethő, László; Guerra‐Nuñez, Carlos; Frey, Damian; Breguet, J.-M.; Michler, Johann

doi:10.1021/acs.nanolett.8b05024

Cited by 43 publications

(36 citation statements)

References 57 publications

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“…Similar strain-rate-dependent results in a microscale glass (22) as well as bulk metallic glasses close to the glass transition temperature have been reported (23,24), showing a cross-over from a ductile behavior at low strain rates to brittle response at increased strain rates. For example, a microscale glass exhibits a homogeneous to inhomogeneous plastic flow transition with increasing strain rate to 6 s −1 (22). Detailed analysis of the coupling effects between mechanical stress and thermal activation has been studied in numerous molecular dynamics (MD) simulations (25)(26)(27), although the typical strain rates attainable using MD are several orders of magnitude higher than those in laboratory tests.…”

supporting

confidence: 82%

“…Discontinuity in particle diffusion has been observed when shearing colloidal glasses at a critical strain rate, indicating a transition from homogeneous to inhomogeneous flow (21). Similar strain-rate-dependent results in a microscale glass (22) as well as bulk metallic glasses close to the glass transition temperature have been reported (23,24), showing a cross-over from a ductile behavior at low strain rates to brittle response at increased strain rates. For example, a microscale glass exhibits a homogeneous to inhomogeneous plastic flow transition with increasing strain rate to 6 s −1 (22).…”

supporting

confidence: 67%

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Potential energy landscape activations governing plastic flows in glass rheology

Cao

Short

Yip

2019

Proc. Natl. Acad. Sci. U.S.A.

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While glasses are ubiquitous in natural and manufactured materials, the atomic-level mechanisms governing their deformation and how these mechanisms relate to rheological behavior are still open questions for fundamental understanding. Using atomistic simulations spanning nearly 10 orders of magnitude in the applied strain rate we probe the atomic rearrangements associated with 3 characteristic regimes of homogeneous and heterogeneous shear flow. In the low and high strain-rate limits, simulation results together with theoretical models reveal distinct scaling behavior in flow stress variation with strain rate, signifying a nonlinear coupling between thermally activated diffusion and stress-driven motion. Moreover, we find the emergence of flow heterogeneity is closely correlated with extreme values of local strain bursts that are not readily accommodated by immediate surroundings, acting as origins of shear localization. The atomistic mechanisms underlying the flow regimes are interpreted by analyzing a distance matrix of nonaffine particle displacements, yielding evidence of various barrier-hopping processes on a fractal potential energy landscape (PEL) in which shear transformations and liquid-like regions are triggered by the interplay of thermal and stress activations.

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supporting

confidence: 82%

supporting

confidence: 67%

Potential energy landscape activations governing plastic flows in glass rheology

Cao

Short

Yip

2019

Proc. Natl. Acad. Sci. U.S.A.

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“…A wider look suggests considering the eventual interaction physics of multiple bands present in the sample, where their interaction with others and with the sample or disorder would be crucial (43). In the same vein, propagating bands of deformation with serrations of the stress-strain curve are also seen in the plastic deformation of amorphous materials (44,45). An obvious question would be if these also can be shown to follow ABBM-like dynamics with a careful study, but then again, if such bands do not follow this simplest paradigm, that is also of profound interest.…”

Section: Discussionmentioning

confidence: 99%

Propagating bands of plastic deformation in a metal alloy as critical avalanches

Mäkinen

Karppinen²,

Ovaska

et al. 2020

Sci. Adv.

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The plastic deformation of metal alloys localizes in the Portevin–Le Chatelier effect in bands of different types, including propagating, or type “A” bands, usually characterized by their width and a typical propagation velocity. This plastic instability arises from collective dynamics of dislocations interacting with mobile solute atoms, but the resulting sensitivity to the strain rate lacks fundamental understanding. Here, we show, by using high-resolution imaging in tensile deformation experiments of an aluminum alloy, that the band velocities exhibit large fluctuations. Each band produces a velocity signal reminiscent of crackling noise bursts observed in numerous driven avalanching systems from propagating cracks in fracture to the Barkhausen effect in ferromagnets. The statistical features of these velocity bursts including their average shapes and size distributions obey predictions of a simple mean-field model of critical avalanche dynamics. Our results thus reveal a previously unknown paradigm of criticality in the localization of deformation.

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“…Unfortunately, owing to the lack of specialised instrumentation the strain rates achievable under micropillar compression has been largely limited to less than 0.1 s −1 . Though recently, the authors of this study reported the micromechanical properties of fused silica and 3D-printed polymer structures at strain rates up to 1000 s −1 using a piezobased testing platform [15,16]. There are also a small number of other recent key studies on copper micropillar compression conducted at strain rates up to 100 s −1 and nanoindentation of coarse-grained aluminium and nanocrystalline nickel performed at indentation strain rates up to 100 s −1 [17,18].…”

Section: Introductionmentioning

confidence: 94%

High strain rate in situ micropillar compression of a Zr-based metallic glass

Ramachandramoorthy

Yang

Casari

et al. 2021

Journal of Materials Research

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High strain rate micromechanical testing can assist researchers in elucidating complex deformation mechanisms in advanced material systems. In this work, the interactions of atomic-scale chemistry and strain rate in affecting the deformation response of a Zr-based metallic glass was studied by varying the concentration of oxygen dissolved into the local structure. Compression of micropillars over six decades of strain rate uncovered a remarkable reversal of the strain rate sensitivity from negative to positive above ~ 5 s−1 due to a delocalisation of shear transformation events within the pre-yield linear regime for both samples, while a higher oxygen content was found to generally decrease the strain rate sensitivity effect. It was also identified that the shear band propagation speed increases with the actuation speed, leading to a transition in the deformation behaviour from serrated to apparent non-serrated plastic flow at ~ 5 s−1. Graphic abstract

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Dynamic Plasticity and Failure of Microscale Glass: Rate-Dependent Ductile–Brittle–Ductile Transition

Cited by 43 publications

References 57 publications

Potential energy landscape activations governing plastic flows in glass rheology

Potential energy landscape activations governing plastic flows in glass rheology

Propagating bands of plastic deformation in a metal alloy as critical avalanches

High strain rate in situ micropillar compression of a Zr-based metallic glass

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