Mapping Shear Bands in Metallic Glasses: From Atomic Structure to Bulk Dynamics

Sheng, Huaping; Şopu, Daniel; Fellner, Simon; Eckert, Jürgen; Gammer, Christoph

doi:10.1103/physrevlett.128.245501

Cited by 22 publications

(4 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The decreases of G and τ with a reduction of ϕ lead to the selfcatalytic growth of density fluctuation under shear deformation: Lower density regions become softer and faster, i.e., easier to deform. Such behaviour has recently been directly observed in metallic glasses by transmission electron microscopy 39 .…”

Section: Resultsmentioning

confidence: 75%

“…There are many pieces of evidence for significant density decrease and the resulting cavitation upon fracture of various amorphous materials (e.g., polymers 30 , rubbers 31 , oxides 32 and metallic glasses [33][34][35][36][37][38] ). Very recently, Sheng et al 39 succeeded in directly observing atomic-scale density alternation of deformed metallic glasses with transmission electron microscopy, revealing the autocatalytic generation of shear transformation zones. Molecular dynamics (MD) simulations can access microscopic information such as quadrupolar localized rearrangements, their coupling, microscopic plastic events, and shear band formation [40][41][42][43][44] .…”

mentioning

confidence: 99%

See 1 more Smart Citation

Fatigue fracture mechanism of amorphous materials from a density-based coarse-grained model

Kurotani

Tanaka

2022

Commun Mater

View full text Add to dashboard Cite

Fatigue fracture is a unique failure mode of materials induced by repeated loading and is crucial for the long-term stability of materials used in cars and aeroplanes. Fatigue is the progressive and localised structural damage of a material subjected to cyclic loading. The minimum strain amplitude that causes such damage is much less than the material’s yield strain under simple loading. This observation leads to a widespread belief that the threshold strain amplitude for fatigue fracture is much smaller than that for monotonic fracture under continuous loading. Here, we study the physical mechanism of the low-cycle fatigue fracture of amorphous solids by considering the complex coupling between density, deformation (velocity), and stress. Contrary to the common belief, we find that the critical strain amplitude, i.e., the onset of irreversible deformation, is the same for fatigue and monotonic fractures. Experimental verification of this prediction is desirable.

show abstract

Section: Resultsmentioning

confidence: 75%

mentioning

confidence: 99%

Fatigue fracture mechanism of amorphous materials from a density-based coarse-grained model

Kurotani

Tanaka

2022

Commun Mater

View full text Add to dashboard Cite

show abstract

“…Very recently, Sheng et al associated a nanoscale density map from a 4D-STEM experiment with MD simulation and predicted the formation of such Eshelby-like strain concentration along the shear front in a metallic glass. [46] The resulting plastically deformed zones concentrate the stress. The concentrated stress perturbs the surrounding material in a vortex-like manner and percolates the neighboring inclusions.…”

Section: Discussionmentioning

confidence: 99%

Direct Observation of Quadrupolar Strain Fields forming a Shear Band in Metallic Glasses

et al. 2023

View full text Add to dashboard Cite

For decades, scanning/transmission electron microscopy (S/TEM) techniques have been employed to analyze shear bands in metallic glasses and understand their formation in order to improve the mechanical properties of metallic glasses. However, due to a lack of direct information in reciprocal space, conventional S/TEM cannot characterize the local strain and atomic structure of amorphous materials, which are key to describe the deformation of glasses. For this work, 4-dimensional-STEM (4D-STEM) is applied to map and directly correlate the local strain and the atomic structure at the nanometer scale in deformed metallic glasses. Residual strain fields are observed with quadrupolar symmetry concentrated at dilated Eshelby inclusions. The strain fields percolate in a vortex-like manner building up the shear band. This provides a new understanding of the formation of shear bands in metallic glass.

show abstract

“…The diffraction intensity in the radial direction of the nanobeam diffraction pattern re ects the distances between atoms in the nanoscale volume, giving rise to information on the atomic density under the approximation that no considerable chemical variations are present. Following previous works 30,31 , we estimated the relative atomic density by calculating the area encircled by the 1st ring of each diffraction pattern in the 4D-STEM data. This approach takes the elliptical deviation of the diffraction rings due to deviatoric strain into account and is an intuitive way to analyze the volumetric strain and disentangle the density information from the sample thickness variation.…”

Section: Development Of Simultaneous Magnetic and Atomic Structure Ma...mentioning

confidence: 99%

Large-angle Lorentz 4D-STEM for Simultaneous Magnetic and Atomic Structure Mapping

Kang,

Mu,

Töllner

et al. 2024

Preprint

View full text Add to dashboard Cite

Achieving a correlative measurement of both magnetic and atomic structures at the nanoscale is imperative to understand the fundamental magnetism of matters and for fostering the development of new magnetic nanomaterials. Conventional microscopy methods fall short in providing the two information simultaneously. Here, we develop a new approach, large-angle Lorentz 4-dimensional scanning transmission electron microscopy (LA-Ltz-4D-STEM), to simultaneously map the magnetic field and atomic structure at the nanoscale. This method enables precise measurement of the characteristic atomic and magnetic structures across an extensive field of view, a critical aspect for investigating real-world ferromagnetic materials. The pixel-by-pixel correlation of the different information offers comprehensive visualization and statistical evaluation of the nanoscale magnetic phenomena. We applied the new method to directly visualize the magnetoelastic coupling as well as the competition between magnetoelastic and magnetostatic energy in an amorphous ferromagnet. This approach opens new avenues for in-depth studying the structure-property correlation of nanoscale magnetic materials.

show abstract

Mapping Shear Bands in Metallic Glasses: From Atomic Structure to Bulk Dynamics

Cited by 22 publications

References 23 publications

Fatigue fracture mechanism of amorphous materials from a density-based coarse-grained model

Fatigue fracture mechanism of amorphous materials from a density-based coarse-grained model

Direct Observation of Quadrupolar Strain Fields forming a Shear Band in Metallic Glasses

Large-angle Lorentz 4D-STEM for Simultaneous Magnetic and Atomic Structure Mapping

Contact Info

Product

Resources

About