Elastic Heterogeneity in Metallic Glasses

Dmowski, W.; Iwashita, Takuya; Chuang, Chiao‐Lin; Almer, Jonathan; Egami, T.

doi:10.1103/physrevlett.105.205502

Cited by 291 publications

(172 citation statements)

References 18 publications

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“…This effect is caused by the existence of soft or loosely packed and hard or densely packed zones in metallic glasses. The total volume of these anelastic sites can occupy as much as a quarter of the volume of the whole sample 25 . Our measurements of the statistical variation in the apparent Young's modulus on the polished surfaces of the selected metallic glasses show a similar wide distribution (Fig.…”

Section: Resultsmentioning

confidence: 99%

On cryothermal cycling as a method for inducing structural changes in metallic glasses

et al. 2018

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The influence of cryothermal treatment on the mechanical properties of metallic glasses with different compositions was investigated in the present work. It was found that cryothermal cycling can induce rejuvenation as well as relaxation of the metallic glasses. The local apparent Young's modulus and its spatial distribution width on the surface of the metallic glass increase after cryothermal cycling, while in the bulk the effect depends on the glass composition. It appeared that this increase is temporary and disappears after a period of room temperature aging. This effect is connected with a large distribution of relaxation times in the metallic glasses due to their heterogeneous structure and the formation of complex native oxides on the outer surfaces of the glasses. Our findings reveal that a cryothermal cycling treatment can improve or degrade the plasticity of a metallic glass, and the atomic bond structure appears to be very important for the outcome of the treatment.

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Section: Resultsmentioning

confidence: 99%

On cryothermal cycling as a method for inducing structural changes in metallic glasses

et al. 2018

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“…More recently, Dmowski and coworkers suggested, from x-ray scattering data, that only about three-quarters of the atoms in a metallic glass deform elastically, with the remainder being anelastic "liquidlike" material. 38 …”

Section: Characteristics Of Non-affine Displacementsmentioning

confidence: 99%

Length-scale dependence of elastic strain from scattering measurements in metallic glasses

et al. 2012

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Several recent studies have reported that the elastic strain in metallic glasses, as measured from peak shifts in the pair correlation functions of samples under load, increases with distance from an average atom, approaching the macroscopic strain at large distances. We have verified this behavior using high-energy x-ray scattering on metallic glasses loaded under uniaxial compression, uniaxial tension, and pure shear, and show that the apparent length-scale dependence of elastic strain is not an artifact of the assumption of structural isotropy in the data analysis. Molecular dynamics simulations of a binary Lennard-Jones glass loaded in uniaxial tension reproduce, qualitatively, the behavior observed in the experiments when the elastic strain is calculated from the shifts in the peaks of the pair correlation function. Under hydrostatic loading, however, the length-scale dependence of elastic strain observed in the simulations is greatly reduced. This suggests that non-affine atomic displacements, which are smaller under hydrostatic loading than under uniaxial loading, may play a key role in the length-scale dependence of elastic strain. Furthermore, no length-scale dependence is observed in simulations, for either uniaxial or hydrostatic loading, when the elastic strain is calculated from the average local deformation gradient tensor. We explain this apparent contradiction and show that the atomic displacements resulting from elastic loading are largest in the low density regions between atomic shells around an average atom. Finally, we present an analysis of length-scale dependence of elastic strain calculated from the pair correlation function for the case of homogeneous deformation, which is in good agreement with the simulations conducted under hydrostatic loading. For uniaxial loading, however, the analysis diverges from both the experimental and simulated results in the first two near-neighbor atomic shells. This suggests, in agreement with our observations from the molecular dynamics simulations, that the observed length-scale dependence of elastic strain from scattering measurements reflects the nature of the non-affine atomic displacements in the glass.

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“…Several studies have suggested that amorphous solids do not possess a truly elastic response regime [6,7,9,16,[19][20][21]. For example, both a sublinear increase of stress versus strain (left inset to Fig.…”

Section: Introductionmentioning

confidence: 99%

Effects of cooling rate on particle rearrangement statistics: Rapidly cooled glasses are more ductile and less reversible

et al. 2017

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Amorphous solids, such as metallic, polymeric, and colloidal glasses, display complex spatiotemporal response to applied deformations. In contrast to crystalline solids, during loading, amorphous solids exhibit a smooth crossover from elastic response to plastic flow. In this study, we investigate the mechanical response of binary Lennard-Jones glasses to athermal, quasistatic pure shear as a function of the cooling rate used to prepare them. We find several key results concerning the connection between strain-induced particle rearrangements and mechanical response. We show that the energy loss per strain dU loss /dγ caused by particle rearrangements for more rapidly cooled glasses is larger than that for slowly cooled glasses. We also find that the cumulative energy loss U loss can be used to predict the ductility of glasses even in the putative linear regime of stress versus strain. U loss increases (and the ratio of shear to bulk moduli decreases) with increasing cooling rate, indicating enhanced ductility. In addition, we characterized the degree of reversibility of particle motion during a single shear cycle. We find that irreversible particle motion occurs even in the linear regime of stress versus strain. However, slowly cooled glasses, which undergo smaller rearrangements, are more reversible during a single shear cycle than rapidly cooled glasses. Thus, we show that more ductile glasses are also less reversible.

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Elastic Heterogeneity in Metallic Glasses

Cited by 291 publications

References 18 publications

On cryothermal cycling as a method for inducing structural changes in metallic glasses

On cryothermal cycling as a method for inducing structural changes in metallic glasses

Length-scale dependence of elastic strain from scattering measurements in metallic glasses

Effects of cooling rate on particle rearrangement statistics: Rapidly cooled glasses are more ductile and less reversible

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