The influence of deformation on the medium-range order of a Zr-based bulk metallic glass characterized by variable resolution fluctuation electron microscopy

Hilke, Sven; Rösner, Harald; Geißler, David; Gebert, A.; Peterlechner, Martin; Wilde, Gerhard

doi:10.1016/j.actamat.2019.04.023

Cited by 64 publications

(42 citation statements)

References 69 publications

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“…At the same time, continuum mechanics models which assume a periodic alignment of quadrupolar stress-field perturbations need to be modified in order to account for this separation of length scales [20]. Interestingly, the average STZ-distance agrees well with recent experimental reports on medium range order [31]. This highlights further the close connection between local structural features and the self-organization of shear transformation events [21,32].…”

Section: Introductionsupporting

confidence: 78%

Probing the Degree of Heterogeneity within a Shear Band of a Model Glass

2019

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Recent experiments provide evidence for density variations along shear bands (SB) in metallic glasses with a length scale of a few hundreds nanometers. Via molecular dynamics simulations of a generic binary glass model, here we show that this is strongly correlated with variations of composition, coordination number, viscosity and heat generation. Individual shear events along the SB-path show a mean distance of a few nanometers, comparable to recent experimental findings on medium range order. The aforementioned variations result from these localized perturbations, mediated by elasticity.

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Section: Introductionsupporting

confidence: 78%

Probing the Degree of Heterogeneity within a Shear Band of a Model Glass

2019

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“…FEM is a microscopic technique which has been shown to be sensitive to higher order correlation functions such as g 3 and g 4 and hence to MRO in disordered materials 7,8,20,23,[26][27][28][29][30][31]46 . A statistical analysis of the diffracted intensities I( k, R, r) from nanometer-sized volumes was used by utilizing STEM microdiffraction 25 , where k is the scattering vector, R is the probe size and r is the position on the sample.…”

Section: Methodsmentioning

confidence: 99%

“…Low-temperature heat capacity measurements (PPMS) were performed in order to reveal changes in the atomic vibrational spectra which are related to the excess free volume distribution 18,19 and thus atomic arrangements. To investigate the corresponding amorphous structure in detail, fluctuation electron microscopy (FEM) was employed to determine the MRO fingerprint (size 7,20 , relative volume fraction 21,22 and types 23,24 ) of each materials' state 20,[25][26][27][28][29][30][31] . Finally, these findings are discussed in terms of a PEL scheme offering a new approach for MRO engineering of glasses.…”

Section: Introductionmentioning

confidence: 99%

Impact of Severe Deformation by HPT at Room Temperature on the Relaxation of the Glassy and the Supercooled Liquid States of PdNiP

et al. 2019

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The impact of severe plastic deformation by high-pressure torsion on the relaxation of the glassy and supercooled liquid states of Pd 40 Ni 40 P 20 was investigated using a combination of differential scanning calorimetry, low-temperature heat capacity and fluctuation electron microscopy. The changes in the calorimetric signals due to deformation and subsequent heat treatments were analyzed and a correlation between deformation (rejuvenation) and annealing (relaxation) was found in relation to medium-range order (MRO). Moreover, a coupling between the occurrence of an exothermic peak in the supercooled liquid state and specific changes in the MRO types were identified. These findings are comprehended in a potential energy landscape scheme offering a new approach for MRO engineering of glasses.

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“…Amorphous solidsespecially bulk metallic glasses (BMGs)are highly attractive for the experimental observation of the effect of strain on diffusion without macroscopic microstructural changes of the material due to the absence of clearly defined atomic planes or crystal structures 8,9 . These characteristics of amorphous alloys are closely related to their unique atomic structure, i.e., dense random packing of the constituent elements and the absence of crystalline periodicity or microstructure [8][9][10] , even though recent results indicate deformation-induced modifications of the medium-range order 11 .…”

mentioning

confidence: 99%

“…Atomic transport and diffusion in amorphous alloys or BMGs are of considerable interest not only from a basic scientific point of view but also for various technical applications of metallic glasses [8][9][10][11][12][13][14][15][16] . Many reports can be found in the literature that attempt to understand the diffusion process of amorphous systems [8][9][10][11][12][13][14][15][16] . Moreover, the effect of strain, induced by (severe) plastic deformation (i.e., cold-rolling) on the diffusion behavior of as-cast BMGs has been investigated 13,14 .…”

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confidence: 99%

Strain perceptibility of elements on the diffusion in Zr-based amorphous alloys

Lee

Kim

Jang

et al. 2020

Sci Rep

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With the discovery of bulk metallic glasses (BMGs), there has been considerable interest in understanding their mechanical behavior. In spite of these previous observations on the relation between plastic deformation of metallic glasses and their diffusion behavior, a detailed understanding on the diffusion of BMGs is still unexplored. We evaluated the contribution of deformation-induced structural transformations (elastic, anelastic, viscoplastic or viscoelastic responsive and plastic strain) on the diffusion of Zr-based bulk metallic glasses in as-cast, elastostatically stressed and plastically deformed states. Experimental investigations of the diffusion process and the elemental distributions in the glassy alloy were performed following plastic deformation by multiple cold rolling and elastostatic cyclic compression, respectively. We compared the vacancy model and the transition state model to verify the diffusion mechanism in the deformed bulk metallic glass. The diffusion of tracer atoms, i.e., Fe, in the bulk metallic glass is affected by viscoelastic responsive strain governing the transition-state model. In contrast, the diffusion of constituent atoms, i.e., Ti, Zr, in the bulk metallic glass is dominantly affected by plastic strain governing the vacancy model. The results reveal that the diffusion behavior of bulk glassy alloys can be changed by variation of the constituent elements and applying different strain modes upon deformation.

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The influence of deformation on the medium-range order of a Zr-based bulk metallic glass characterized by variable resolution fluctuation electron microscopy

Cited by 64 publications

References 69 publications

Probing the Degree of Heterogeneity within a Shear Band of a Model Glass

Probing the Degree of Heterogeneity within a Shear Band of a Model Glass

Impact of Severe Deformation by HPT at Room Temperature on the Relaxation of the Glassy and the Supercooled Liquid States of PdNiP

Strain perceptibility of elements on the diffusion in Zr-based amorphous alloys

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