1
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Li YW, Yao Y, Ciamarra MP. Local Plastic Response and Slow Heterogeneous Dynamics of Supercooled Liquids. PHYSICAL REVIEW LETTERS 2022; 128:258001. [PMID: 35802437 DOI: 10.1103/physrevlett.128.258001] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 04/26/2022] [Accepted: 06/07/2022] [Indexed: 06/15/2023]
Abstract
We demonstrate, via numerical simulations, that the relaxation dynamics of supercooled liquids correlates well with a plastic length scale measuring a particle's response to impulsive localized perturbations and weakly to measures of local elasticity. We find that the particle averaged plastic length scale vanishes linearly in temperature and controls the super-Arrhenius temperature dependence of the relaxation time. Furthermore, we show that the plastic length scale of individual particles correlates with their typical displacement at the relaxation time. In contrast, the local elastic response only correlates with the dynamics on the vibrational timescale.
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Affiliation(s)
- Yan-Wei Li
- Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, 100081, China
| | - Yugui Yao
- Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, 100081, China
| | - Massimo Pica Ciamarra
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore, CNR-SPIN, Dipartimento di Scienze Fisiche, Università di Napoli Federico II, I-80126, Napoli, Italy and CNRS@CREATE LTD, 1 Create Way, No. 08-01 CREATE Tower, Singapore 138602, Singapore
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2
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Lemaître A. Stress hyperuniformity and transient oscillatory-exponential correlation decay as signatures of strength vs fragility in glasses. J Chem Phys 2021; 155:194501. [PMID: 34800950 DOI: 10.1063/5.0065613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We examine and compare the local stress autocorrelation in the inherent states of a fragile and a strong glass: the Kob-Andersen (KA) binary mixture and the Beest-Kramer-Santen model of silica. For both systems, local (domain-averaged) stress fluctuations asymptotically reach the normal inverse-volume decay in the large domain limit; accordingly, the real-space stress autocorrelation presents long-range power law tails. However, in the case of silica, local stress fluctuations display a high degree of hyperuniformity, i.e., their asymptotic (normal) decay is disproportionately smaller than their bond level amplitude. This property causes the asymptotic power law tails of the real-space stress autocorrelation to be swamped, up to very large distances (several nanometers), by an intermediate oscillatory-exponential decay regime. Similar contributions exist in the KA stress autocorrelation, but they never can be considered as dominating the power law decay and fully disappear when stress is coarse-grained beyond one interatomic distance. Our observations document that the relevance of power-law stress correlation may constitute a key discriminating feature between strong and fragile glasses. Meanwhile, they highlight that the notion of local stress in atomistic systems involves by necessity a choice of observation (coarse-graining) scale, the relevant value of which depends, in principle, on both the model and the phenomenon studied.
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Affiliation(s)
- Anaël Lemaître
- Navier, Ecole des Ponts, Univ Gustave Eiffel, CNRS, Marne-la-Vallée, France
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3
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Fan H, Fan Z, Liu X, Lu Z, Ma E. Atomic vibration as an indicator of the propensity for configurational rearrangements in metallic glasses. MATERIALS HORIZONS 2021; 8:2359-2372. [PMID: 34870291 DOI: 10.1039/d1mh00491c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In a metallic glass (MG), the propensity for atomic rearrangements varies spatially from location to location in the amorphous solid, making the prediction of their likelihood a major challenge. One can attack this problem from the "structure controls properties" standpoint. But all the current structure-centric parameters are mostly based on local atomic packing information limited to short-range order, hence falling short in reliably forecasting how the local region would respond to external stimuli (e.g., temperature and/or stress). Alternatively, one can use indicators informed by physical properties to bridge the static structure on the one hand, and the response of the local configuration on the other. A sub-group of such physics-informed quantities consists of atomic vibration parameters, which will be singled out as the focus of this article. Here we use the Cu64Zr36 alloy to systematically demonstrate the following two points, all using a single model MG. First, we show in a comprehensive manner the interrelation among common vibrational parameters characterizing the atomic vibrational amplitude and frequency, including the atomic mean square displacement, flexibility volume, participation fraction in the low-frequency vibrational modes and boson peak intensity. Second, we demonstrate that these vibrational parameters fare much better than purely static structural parameters based on local geometrical packing in providing correlation with the propensity for local configurational transitions. These vibrational parameters also share a correlation length similar to that in structural rearrangements induced by external stimuli. This success, however, also poses a challenge, as it remains to be elucidated as to why short-time dynamical (vibrational) behavior at the bottom of the energy basin can be exploited to project the height of the energy barrier for cross-basin activities and in turn the propensity for locally collective atomic rearrangements.
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Affiliation(s)
- Huiyang Fan
- State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing, 100083, China.
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Zhao Fan
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Xiongjun Liu
- State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing, 100083, China.
| | - Zhaoping Lu
- State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing, 100083, China.
| | - En Ma
- Center for Alloy Innovation and Design (CAID), State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China.
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4
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Ma X, Mishra CK, Habdas P, Yodh AG. Structural and short-time vibrational properties of colloidal glasses and supercooled liquids in the vicinity of the re-entrant glass transition. J Chem Phys 2021; 155:074902. [PMID: 34418931 DOI: 10.1063/5.0059084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
We investigate the short-time vibrational properties and structure of two-dimensional, bidisperse, colloidal glasses and supercooled liquids in the vicinity of the re-entrant glass transition, as a function of interparticle depletion attraction strength. The long-time spatiotemporal dynamics of the samples are measured to be non-monotonic, confirming that the suspensions evolve from repulsive glass to supercooled liquid to attractive glass with increasing depletion attraction. Here, we search for vibrational signatures of the re-entrant behavior in the short-time spatiotemporal dynamics, i.e., dynamics associated with particle motion inside its nearest-neighbor cage. Interestingly, we observe that the anharmonicity of these in-cage vibrations varies non-monotonically with increasing attraction strength, consistent with the non-monotonic long-time structural relaxation dynamics of the re-entrant glass. We also extract effective spring constants between neighboring particles; we find that spring stiffness involving small particles also varies non-monotonically with increasing attraction strength, while stiffness between large particles increases monotonically. Last, from study of depletion-dependent local structure and vibration participation fractions, we gain microscopic insight into the particle-size-dependent contributions to short-time vibrational modes in the glass and supercooled liquid states.
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Affiliation(s)
- Xiaoguang Ma
- Center for Complex Flows and Soft Matter Research, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Chandan K Mishra
- Discipline of Physics, Indian Institute of Technology (IIT) Gandhinagar Palaj, Gandhinagar, Gujarat 382355, India
| | - P Habdas
- Department of Physics, Saint Joseph's University, Philadelphia, Pennsylvania 19131, USA
| | - A G Yodh
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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5
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Ruscher C, Rottler J. Residual stress distributions in amorphous solids from atomistic simulations. SOFT MATTER 2020; 16:8940-8949. [PMID: 32901650 DOI: 10.1039/d0sm01155j] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The distribution of local residual stresses (threshold to instability) that controls the statistical properties of plastic flow in athermal amorphous solids is examined with an atomistic simulation technique. For quiescent configurations, the distribution has a pseudogap (power-law) form with an exponent that agrees well with global yielding statistics. As soon as deformation sets in, the pseudogap region gives way to a system size dependent plateau at small residual stresses that can be understood from the statistics of local residual stress differences between plastic events. Results further suggest that the local yield stress in amorphous solids changes even if the given region does not participate in plastic activity.
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Affiliation(s)
- Céline Ruscher
- Institut Charles Sadron, 23 rue du Loess, F-67034 Strasbourg, France. and Department of Physics and Astronomy and Quantum Matter Institute, University of British Columbia, Vancouver, BC V6T 1Z1, Canada.
| | - Jörg Rottler
- Department of Physics and Astronomy and Quantum Matter Institute, University of British Columbia, Vancouver, BC V6T 1Z1, Canada.
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6
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Vasisht VV, Del Gado E. Computational study of transient shear banding in soft jammed solids. Phys Rev E 2020; 102:012603. [PMID: 32795069 DOI: 10.1103/physreve.102.012603] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2019] [Accepted: 05/29/2020] [Indexed: 11/07/2022]
Abstract
We have designed three-dimensional numerical simulations of a soft spheres model, with size polidispersity and in athermal conditions, to study the transient shear banding that occurs during yielding of jammed soft solids. We analyze the effects of different types of drag coefficients used in the simulations and compare the results obtained using Lees-Edwards periodic boundary conditions with the case in which the same model solid is confined between two walls. The specific damping mechanism and the different boundary conditions indeed modify the load curves and the velocity profiles in the transient regime. Nevertheless, we find that the presence of a stress overshoot and of a related transient banding phenomenon, for large enough samples, is a robust feature for overdamped systems, where their presence do not depend on the specific drag used and on the different boundary conditions.
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Affiliation(s)
- Vishwas V Vasisht
- Indian Institute of Technology Palakkad, Ahalia Integrated Campus, Kozhippara P.O. - Palakkad, Kerala 678557, India.,Department of Physics, Institute for Soft Matter Synthesis and Metrology, Georgetown University, 37th and O Streets, N.W., Washington, DC 20057, USA
| | - Emanuela Del Gado
- Department of Physics, Institute for Soft Matter Synthesis and Metrology, Georgetown University, 37th and O Streets, N.W., Washington, DC 20057, USA
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Iyer SS, Srivastava A. Degeneracy in molecular scale organization of biological membranes. SOFT MATTER 2020; 16:6752-6764. [PMID: 32628232 DOI: 10.1039/d0sm00619j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The scale-rich spatiotemporal organization in biological membranes has its origin in the differential inter- and intra-molecular interactions among their constituents. In this work, we explore the molecular-origin behind that variety and possible degeneracy in lateral organization in membranes. For our study, we post-process microsecond long all-atom molecular dynamics trajectories for three systems that exhibit fluid phase coexistence: (i) PSM/POPC/Chol (0.47/0.32/0.21), (ii) PSM/DOPC/Chol (0.43/0.38/0.19) and (iii) DPPC/DOPC/Chol (0.37/0.36/0.27). To distinguish the liquid ordered and disordered regions at molecular scales, we calculate the degree of non-affineness of individual lipids in their neighbourhood and track their topological rearrangements. Disconnectivity graph analysis with respect to membrane organization shows that the DPPC/DOPC/Chol and PSM/DOPC/Chol systems exhibit funnel-like energy landscapes as opposed to a highly frustrated energy landscape for the more biomimetic PSM/POPC/Chol system. We use these measurements to develop a continuous lattice Hamiltonian and evolve that using Monte Carlo simulated annealing to explore the possibility of structural degeneracy in membrane organization. Our data show that model membranes with lipid constituents that are biomimetic (PSM/POPC/Chol) have the ability to access a large range of membrane sub-structure space (higher degeneracy) as compared to the other two systems, which form only one kind of substructure even with changing composition. Since the spatiotemporal organization in biological membranes dictates the "molecular encounters" and in turn larger scale biological processes such as molecular transport, trafficking and cellular signalling, we posit that this structural degeneracy could enable access to a larger repository to functionally important molecular organization in systems with physiologically relevant compositions.
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Affiliation(s)
- Sahithya S Iyer
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India.
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8
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Zong Y, Chen K, Mason TG, Zhao K. Vibrational Modes and Dynamic Heterogeneity in a Near-Equilibrium 2D Glass of Colloidal Kites. PHYSICAL REVIEW LETTERS 2018; 121:228003. [PMID: 30547612 DOI: 10.1103/physrevlett.121.228003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 09/04/2018] [Indexed: 06/09/2023]
Abstract
Using video microscopy and particle-tracking techniques developed for dense Brownian systems of polygons, we study the structure-dynamics relationship in a near-equilibrium 2D glass consisting of anisotropic Penrose kite-shaped colloids. Detailed vibrational properties of kite glasses, both translational and rotational, are obtained using covariance matrix techniques. Different from other colloidal glasses of spheres and ellipsoids, the vibrational modes of kite glasses at low frequencies show a strong translational character with spatially localized rotational modes and extended translational modes. Low-frequency quasilocalized soft modes commonly found in sphere glasses are absent in the translational phonon modes of kite glasses. Soft modes are observed predominantly in the rotational vibrations and correlate well with the spatial distribution of Debye-Waller factors. The local structural entropy field shows a strong correlation with the observed dynamic heterogeneity.
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Affiliation(s)
- Yiwu Zong
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People's Republic of China
| | - Ke Chen
- Beijing National Laboratory for Condensed Matter Physics and Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, People's Republic of China
| | - Thomas G Mason
- Department of Physics and Astronomy, University of California-Los Angeles, Los Angeles, California 90095, USA
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California 90095, USA
| | - Kun Zhao
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People's Republic of China
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9
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Cao Y, Li J, Kou B, Xia C, Li Z, Chen R, Xie H, Xiao T, Kob W, Hong L, Zhang J, Wang Y. Structural and topological nature of plasticity in sheared granular materials. Nat Commun 2018; 9:2911. [PMID: 30046062 PMCID: PMC6060108 DOI: 10.1038/s41467-018-05329-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 06/20/2018] [Indexed: 11/09/2022] Open
Abstract
Upon mechanical loading, granular materials yield and undergo plastic deformation. The nature of plastic deformation is essential for the development of the macroscopic constitutive models and the understanding of shear band formation. However, we still do not fully understand the microscopic nature of plastic deformation in disordered granular materials. Here we used synchrotron X-ray tomography technique to track the structural evolutions of three-dimensional granular materials under shear. We establish that highly distorted coplanar tetrahedra are the structural defects responsible for microscopic plasticity in disordered granular packings. The elementary plastic events occur through flip events which correspond to a neighbor switching process among these coplanar tetrahedra (or equivalently as the rotation motion of 4-ring disclinations). These events are discrete in space and possess specific orientations with the principal stress direction. It is a general consensus that the structural defects are the plasticity carriers in amorphous solids, but its microscopic view remains largely unknown. Cao et a. show that highly distorted coplanar tetrahedra act as defects in granular packings, which flip under shear to carry local plasticity.
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Affiliation(s)
- Yixin Cao
- School of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai, 200240, China
| | - Jindong Li
- School of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai, 200240, China
| | - Binquan Kou
- School of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai, 200240, China
| | - Chengjie Xia
- School of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai, 200240, China
| | - Zhifeng Li
- School of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai, 200240, China
| | - Rongchang Chen
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800, China
| | - Honglan Xie
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800, China
| | - Tiqiao Xiao
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800, China
| | - Walter Kob
- Laboratoire Charles Coulomb, UMR 5521, University of Montpellier and CNRS, 34095, Montpellier, France
| | - Liang Hong
- School of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai, 200240, China.,Institute of Natural Sciences, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jie Zhang
- School of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai, 200240, China.,Institute of Natural Sciences, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yujie Wang
- School of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai, 200240, China. .,Materials Genome Initiative Center, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai, 200240, China. .,Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
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10
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Pinney R, Liverpool TB, Royall CP. Yielding of a model glass former: An interpretation with an effective system of icosahedra. Phys Rev E 2018; 97:032609. [PMID: 29776085 DOI: 10.1103/physreve.97.032609] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Indexed: 11/07/2022]
Abstract
We consider the yielding under simple shear of a binary Lennard-Jones glass former whose super-Arrhenius dynamics are correlated with the formation of icosahedral structures. We recast this glass former as an effective system of icosahedra [Pinney et al., J. Chem. Phys. 143, 244507 (2015)JCPSA60021-960610.1063/1.4938424]. Looking at the small-strain region of sheared simulations, we observe that shear rates affect the shear localization behavior particularly at temperatures below the glass transition as defined with a fit to the Vogel-Fulcher-Tamman equation. At higher temperature, shear localization starts immediately on shearing for all shear rates. At lower temperatures, faster shear rates can result in a delayed start in shear localization, which begins close to the yield stress. Building from a previous work which considered steady-state shear [Pinney et al., J. Chem. Phys. 143, 244507 (2015)JCPSA60021-960610.1063/1.4938424], we interpret the response to shear and the shear localization in terms of a local effective temperature with our system of icosahedra. We find that the effective temperatures of the regions undergoing shear localization increase significantly with increasing strain (before reaching a steady-state plateau).
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Affiliation(s)
- Rhiannon Pinney
- HH Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, United Kingdom.,Bristol Centre for Complexity Science, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Tanniemola B Liverpool
- School of Mathematics, University of Bristol, Bristol BS8 1TW, United Kingdom.,BrisSynBio, Tyndall Avenue, Bristol BS8 1TQ, United Kingdom
| | - C Patrick Royall
- HH Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, United Kingdom.,School of Chemistry, University of Bristol, Cantock Close, Bristol BS8 1TS, United Kingdom.,Centre for Nanoscience and Quantum Information, Tyndall Avenue, Bristol BS8 1FD, United Kingdom
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11
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Xu B, Falk ML, Li JF, Kong LT. Predicting Shear Transformation Events in Metallic Glasses. PHYSICAL REVIEW LETTERS 2018; 120:125503. [PMID: 29694058 DOI: 10.1103/physrevlett.120.125503] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 12/26/2017] [Indexed: 06/08/2023]
Abstract
Shear transformation is the elementary process for plastic deformation of metallic glasses, the prediction of the occurrence of the shear transformation events is therefore of vital importance to understand the mechanical behavior of metallic glasses. In this Letter, from the view of the potential energy landscape, we find that the protocol-dependent behavior of shear transformation is governed by the stress gradient along its minimum energy path and we propose a framework as well as an atomistic approach to predict the triggering strains, locations, and structural transformations of the shear transformation events under different shear protocols in metallic glasses. Verification with a model Cu_{64}Zr_{36} metallic glass reveals that the prediction agrees well with athermal quasistatic shear simulations. The proposed framework is believed to provide an important tool for developing a quantitative understanding of the deformation processes that control mechanical behavior of metallic glasses.
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Affiliation(s)
- Bin Xu
- State key Laboratory of Metal Matrix Composites, School of Materials Science & Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Michael L Falk
- Department of Materials Science and Engineering, Mechanical Engineering, and Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - J F Li
- State key Laboratory of Metal Matrix Composites, School of Materials Science & Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - L T Kong
- State key Laboratory of Metal Matrix Composites, School of Materials Science & Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
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12
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Barbot A, Lerbinger M, Hernandez-Garcia A, García-García R, Falk ML, Vandembroucq D, Patinet S. Local yield stress statistics in model amorphous solids. Phys Rev E 2018; 97:033001. [PMID: 29776106 DOI: 10.1103/physreve.97.033001] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Indexed: 06/08/2023]
Abstract
We develop and extend a method presented by Patinet, Vandembroucq, and Falk [Phys. Rev. Lett. 117, 045501 (2016)PRLTAO0031-900710.1103/PhysRevLett.117.045501] to compute the local yield stresses at the atomic scale in model two-dimensional Lennard-Jones glasses produced via differing quench protocols. This technique allows us to sample the plastic rearrangements in a nonperturbative manner for different loading directions on a well-controlled length scale. Plastic activity upon shearing correlates strongly with the locations of low yield stresses in the quenched states. This correlation is higher in more structurally relaxed systems. The distribution of local yield stresses is also shown to strongly depend on the quench protocol: the more relaxed the glass, the higher the local plastic thresholds. Analysis of the magnitude of local plastic relaxations reveals that stress drops follow exponential distributions, justifying the hypothesis of an average characteristic amplitude often conjectured in mesoscopic or continuum models. The amplitude of the local plastic rearrangements increases on average with the yield stress, regardless of the system preparation. The local yield stress varies with the shear orientation tested and strongly correlates with the plastic rearrangement locations when the system is sheared correspondingly. It is thus argued that plastic rearrangements are the consequence of shear transformation zones encoded in the glass structure that possess weak slip planes along different orientations. Finally, we justify the length scale employed in this work and extract the yield threshold statistics as a function of the size of the probing zones. This method makes it possible to derive physically grounded models of plasticity for amorphous materials by directly revealing the relevant details of the shear transformation zones that mediate this process.
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Affiliation(s)
- Armand Barbot
- PMMH, ESPCI Paris/CNRS-UMR 7636/University Paris 6 UPMC/University Paris 7 Diderot, PSL Research University, 10 rue Vauquelin, 75231 Paris cedex 05, France
| | - Matthias Lerbinger
- PMMH, ESPCI Paris/CNRS-UMR 7636/University Paris 6 UPMC/University Paris 7 Diderot, PSL Research University, 10 rue Vauquelin, 75231 Paris cedex 05, France
| | - Anier Hernandez-Garcia
- PMMH, ESPCI Paris/CNRS-UMR 7636/University Paris 6 UPMC/University Paris 7 Diderot, PSL Research University, 10 rue Vauquelin, 75231 Paris cedex 05, France
| | - Reinaldo García-García
- PMMH, ESPCI Paris/CNRS-UMR 7636/University Paris 6 UPMC/University Paris 7 Diderot, PSL Research University, 10 rue Vauquelin, 75231 Paris cedex 05, France
| | - Michael L Falk
- Departments of Materials Science and Engineering, Mechanical Engineering, and Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Damien Vandembroucq
- PMMH, ESPCI Paris/CNRS-UMR 7636/University Paris 6 UPMC/University Paris 7 Diderot, PSL Research University, 10 rue Vauquelin, 75231 Paris cedex 05, France
| | - Sylvain Patinet
- PMMH, ESPCI Paris/CNRS-UMR 7636/University Paris 6 UPMC/University Paris 7 Diderot, PSL Research University, 10 rue Vauquelin, 75231 Paris cedex 05, France
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13
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Zylberg J, Lerner E, Bar-Sinai Y, Bouchbinder E. Local thermal energy as a structural indicator in glasses. Proc Natl Acad Sci U S A 2017; 114:7289-7294. [PMID: 28655846 PMCID: PMC5514746 DOI: 10.1073/pnas.1704403114] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Identifying heterogeneous structures in glasses-such as localized soft spots-and understanding structure-dynamics relations in these systems remain major scientific challenges. Here, we derive an exact expression for the local thermal energy of interacting particles (the mean local potential energy change caused by thermal fluctuations) in glassy systems by a systematic low-temperature expansion. We show that the local thermal energy can attain anomalously large values, inversely related to the degree of softness of localized structures in a glass, determined by a coupling between internal stresses-an intrinsic signature of glassy frustration-anharmonicity and low-frequency vibrational modes. These anomalously large values follow a fat-tailed distribution, with a universal exponent related to the recently observed universal [Formula: see text] density of states of quasilocalized low-frequency vibrational modes. When the spatial thermal energy field-a "softness field"-is considered, this power law tail manifests itself by highly localized spots, which are significantly softer than their surroundings. These soft spots are shown to be susceptible to plastic rearrangements under external driving forces, having predictive powers that surpass those of the normal modes-based approach. These results offer a general, system/model-independent, physical/observable-based approach to identify structural properties of quiescent glasses and relate them to glassy dynamics.
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Affiliation(s)
- Jacques Zylberg
- Chemical Physics Department, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Edan Lerner
- Institute for Theoretical Physics, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Yohai Bar-Sinai
- Chemical Physics Department, Weizmann Institute of Science, Rehovot 7610001, Israel
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138
| | - Eran Bouchbinder
- Chemical Physics Department, Weizmann Institute of Science, Rehovot 7610001, Israel;
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14
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Pastore R, Pesce G, Sasso A, Pica Ciamarra M. Cage Size and Jump Precursors in Glass-Forming Liquids: Experiment and Simulations. J Phys Chem Lett 2017; 8:1562-1568. [PMID: 28301929 DOI: 10.1021/acs.jpclett.7b00187] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Glassy dynamics is intermittent, as particles suddenly jump out of the cage formed by their neighbors, and heterogeneous, as these jumps are not uniformly distributed across the system. Relating these features of the dynamics to the diverse local environments explored by the particles is essential to rationalize the relaxation process. Here we investigate this issue characterizing the local environment of a particle with the amplitude of its short time vibrational motion, as determined by segmenting in cages and jumps the particle trajectories. Both simulations of supercooled liquids and experiments on colloidal suspensions show that particles in large cages are likely to jump after a small time-lag, and that, on average, the cage enlarges shortly before the particle jumps. At large time-lags, the cage has essentially a constant size, which is smaller for longer-lasting cages. Finally, we clarify how this coupling between cage size and duration controls the average behavior and opens the way to a better understanding of the relaxation process in glass-forming liquids.
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Affiliation(s)
- Raffaele Pastore
- CNR-SPIN, sezione di Napoli, Dipartimento di Fisica, Campus universitario di Monte S. Angelo, Via Cintia, 80126 Napoli, Italy
| | - Giuseppe Pesce
- Dipartimento di Fisica, Universitá di Napoli Federico II, Campus universitario di Monte S. Angelo, Via Cintia, 80126 Napoli, Italy
| | - Antonio Sasso
- Dipartimento di Fisica, Universitá di Napoli Federico II, Campus universitario di Monte S. Angelo, Via Cintia, 80126 Napoli, Italy
| | - Massimo Pica Ciamarra
- CNR-SPIN, sezione di Napoli, Dipartimento di Fisica, Campus universitario di Monte S. Angelo, Via Cintia, 80126 Napoli, Italy
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore , 639798
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15
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Pinney R, Liverpool TB, Royall CP. Structure in sheared supercooled liquids: Dynamical rearrangements of an effective system of icosahedra. J Chem Phys 2017; 145:234501. [PMID: 27984869 DOI: 10.1063/1.4968555] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We consider a binary Lennard-Jones glassformer whose super-Arrhenius dynamics are correlated with the formation of particles organized into icosahedra under simple steady state shear. We recast this glassformer as an effective system of icosahedra [Pinney et al., J. Chem. Phys. 143, 244507 (2015)]. From the observed population of icosahedra in each steady state, we obtain an effective temperature which is linearly dependent on the shear rate in the range considered. Upon shear banding, the system separates into a region of high shear rate and a region of low shear rate. The effective temperatures obtained in each case show that the low shear regions correspond to a significantly lower temperature than the high shear regions. Taking a weighted average of the effective temperature of these regions (weight determined by region size) yields an estimate of the effective temperature which compares well with an effective temperature based on the global mesocluster population of the whole system.
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Affiliation(s)
- Rhiannon Pinney
- HH Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
| | | | - C Patrick Royall
- HH Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
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16
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Ding J, Cheng YQ, Sheng H, Asta M, Ritchie RO, Ma E. Universal structural parameter to quantitatively predict metallic glass properties. Nat Commun 2016; 7:13733. [PMID: 27941922 PMCID: PMC5159863 DOI: 10.1038/ncomms13733] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Accepted: 10/27/2016] [Indexed: 11/09/2022] Open
Abstract
Quantitatively correlating the amorphous structure in metallic glasses (MGs) with their physical properties has been a long-sought goal. Here we introduce ‘flexibility volume' as a universal indicator, to bridge the structural state the MG is in with its properties, on both atomic and macroscopic levels. The flexibility volume combines static atomic volume with dynamics information via atomic vibrations that probe local configurational space and interaction between neighbouring atoms. We demonstrate that flexibility volume is a physically appropriate parameter that can quantitatively predict the shear modulus, which is at the heart of many key properties of MGs. Moreover, the new parameter correlates strongly with atomic packing topology, and also with the activation energy for thermally activated relaxation and the propensity for stress-driven shear transformations. These correlations are expected to be robust across a very wide range of MG compositions, processing conditions and length scales.
Various known structural descriptors of metallic glasses have limitations in quantitatively predicting properties. Here authors define a physically-motivated measure and show it to correlate strongly with elastic properties, local structure and relaxation kinetics over a wide range of simulated compositions.
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Affiliation(s)
- Jun Ding
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.,Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Yong-Qiang Cheng
- Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Howard Sheng
- Department of Physics and Astronomy, George Mason University, Fairfax, Virginia 22030, USA
| | - Mark Asta
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.,Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - Robert O Ritchie
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.,Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - Evan Ma
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
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17
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Patinet S, Vandembroucq D, Falk ML. Connecting Local Yield Stresses with Plastic Activity in Amorphous Solids. PHYSICAL REVIEW LETTERS 2016; 117:045501. [PMID: 27494480 DOI: 10.1103/physrevlett.117.045501] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Indexed: 06/06/2023]
Abstract
In model amorphous solids produced via differing quench protocols, a strong correlation is established between local yield stress measured by direct local probing of shear stress thresholds and the plastic rearrangements observed during remote loading in shear. This purely local measure shows a higher predictive power for identifying sites of plastic activity when compared with more conventional structural properties. Most importantly, the sites of low local yield stress, thus defined, are shown to be persistent, remaining predictive of deformation events even after fifty or more such plastic rearrangements. This direct and nonperturbative approach gives access to relevant transition pathways that control the stability of amorphous solids. Our results reinforce the relevance of modeling plasticity in amorphous solids based on a gradually evolving population of discrete and local zones preexisting in the structure.
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Affiliation(s)
- Sylvain Patinet
- Laboratoire de Physique et Mécanique des Milieux Hétèrogènes (PMMH), UMR CNRS 7636; PSL-ESPCI, 10 rue Vauquelin, 75005 Paris, France; Sorbonne Université-UPMC, Université Paris 06, France; and Sorbonne Paris Cité-UDD, Université Paris 07, France
| | - Damien Vandembroucq
- Laboratoire de Physique et Mécanique des Milieux Hétèrogènes (PMMH), UMR CNRS 7636; PSL-ESPCI, 10 rue Vauquelin, 75005 Paris, France; Sorbonne Université-UPMC, Université Paris 06, France; and Sorbonne Paris Cité-UDD, Université Paris 07, France
| | - Michael L Falk
- Departments of Materials Science and Engineering, Mechanical Engineering, and Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
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18
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Ciamarra MP, Pastore R, Coniglio A. Particle jumps in structural glasses. SOFT MATTER 2016; 12:358-366. [PMID: 26481331 DOI: 10.1039/c5sm01568e] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Particles in structural glasses rattle around temporary equilibrium positions, that seldom change through a process which is much faster than the relaxation time, known as particle jump. Since the relaxation of the system is due to the accumulation of many such jumps, it could be possible to connect the single particle short time motion to the macroscopic relaxation by understanding the features of the jump dynamics. Here we review recent results in this research direction, clarifying the features of particle jumps that have been understood and those that are still under investigation, and examining the role of particle jumps in different theories of the glass transition.
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Affiliation(s)
- Massimo Pica Ciamarra
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore and CNR-SPIN, Dipartimento di Scienze Fisiche, University of Napoli Federico II, Italy.
| | - Raffaele Pastore
- CNR-SPIN, Dipartimento di Scienze Fisiche, University of Napoli Federico II, Italy.
| | - Antonio Coniglio
- CNR-SPIN, Dipartimento di Scienze Fisiche, University of Napoli Federico II, Italy.
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19
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Abstract
We propose a theoretical framework within which a robust micromechanical definition of precursors to plastic instabilities, often termed soft spots, naturally emerges. They are shown to be collective displacements (modes) z[over ̂] that correspond to local minima of a barrier function b(z[over ̂]), which depends solely on inherent structure information. We demonstrate how some heuristic searches for local minima of b(z[over ̂]) can a priori detect the locus and geometry of imminent plastic instabilities with remarkable accuracy, at strains as large as γ_{c}-γ∼10^{-2} away from the instability strain γ_{c}. Our findings suggest that the a priori detection of the entire field of soft spots can be effectively carried out by a systematic investigation of the landscape of b(z[over ̂]).
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Affiliation(s)
- Luka Gartner
- Institute for Theoretical Physics, Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Edan Lerner
- Institute for Theoretical Physics, Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
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20
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Smessaert A, Rottler J. Correlation between rearrangements and soft modes in polymer glasses during deformation and recovery. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:052308. [PMID: 26651696 DOI: 10.1103/physreve.92.052308] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Indexed: 06/05/2023]
Abstract
We explore the link between soft vibrational modes and local relaxation events in polymer glasses during physical aging, active deformation at constant strain rate, and subsequent recovery. A softness field is constructed out of the superposition of the amplitudes of the lowest energy normal modes, and found to predict up to 70% of the rearrangements. Overlap between softness and rearrangements increases logarithmically during aging and recovery phases as energy barriers rise due to physical aging, while yielding rapidly rejuvenates the overlap to that of a freshly prepared glass. In the strain hardening regime, correlations rise for uniaxial tensile deformation but not for simple shear. These trends can be explained by considering the differing degrees of localization of the soft modes in the two deformation protocols.
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Affiliation(s)
- Anton Smessaert
- Department of Physics and Astronomy, The University of British Columbia, 6224 Agricultural Road, Vancouver, British Columbia, Canada V6T 1Z1
| | - Jörg Rottler
- Department of Physics and Astronomy, The University of British Columbia, 6224 Agricultural Road, Vancouver, British Columbia, Canada V6T 1Z1
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21
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Lemaître A. Tensorial analysis of Eshelby stresses in 3D supercooled liquids. J Chem Phys 2015; 143:164515. [DOI: 10.1063/1.4933235] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
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22
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Pastore R, Coniglio A, Ciamarra MP. Spatial correlations of elementary relaxation events in glass-forming liquids. SOFT MATTER 2015; 11:7214-7218. [PMID: 26264078 DOI: 10.1039/c5sm01510c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The dynamical facilitation scenario, by which localized relaxation events promote nearby relaxation events in an avalanche process, has been suggested as the key mechanism connecting the microscopic and the macroscopic dynamics of structural glasses. Here we investigate the statistical features of this process via numerical simulations of a model structural glass. First we show that the relaxation dynamics of the system occurs through particle jumps that are irreversible, and that cannot be decomposed in smaller irreversible events. Then we show that each jump does actually trigger an avalanche. The characteristics of this avalanche change upon cooling, suggesting that the relaxation dynamics crossovers from a noise dominated regime, where jumps do not trigger other relaxation events, to a regime dominated by the facilitation process, where a jump triggers more relaxation events.
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23
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Fiocco D, Foffi G, Sastry S. Memory effects in schematic models of glasses subjected to oscillatory deformation. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:194130. [PMID: 25923880 DOI: 10.1088/0953-8984/27/19/194130] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We consider two schematic models of glasses subjected to oscillatory shear deformation, motivated by the observations, in computer simulations of a model glass, of a nonequilibrium transition from a localized to a diffusive regime as the shear amplitude is increased, and of persistent memory effects in the localized regime. The first of these schematic models is the NK model, a spin model with disordered multi-spin interactions previously studied as a model for sheared amorphous solids. The second model, a transition matrix model, is an abstract formulation of the manner in which occupancy of local energy minima evolves under oscillatory deformation cycles. In both of these models, we find a behavior similar to that of an atomic model glass studied earlier. We discuss possible further extensions of the approaches outlined.
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Affiliation(s)
- Davide Fiocco
- Institute of Theoretical Physics (ITP), Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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24
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Fuereder I, Ilg P. Influence of inherent structure shear stress of supercooled liquids on their shear moduli. J Chem Phys 2015; 142:144505. [DOI: 10.1063/1.4917042] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Affiliation(s)
- Ingo Fuereder
- Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, CH-8093 Zurich, Switzerland
| | - Patrick Ilg
- Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, CH-8093 Zurich, Switzerland
- School of Mathematical and Physical Sciences, University of Reading, Reading RG6 6AX, United Kingdom
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25
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Lemaître A. Structural relaxation is a scale-free process. PHYSICAL REVIEW LETTERS 2014; 113:245702. [PMID: 25541780 DOI: 10.1103/physrevlett.113.245702] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Indexed: 06/04/2023]
Abstract
We show that in deeply supercooled liquids, structural relaxation proceeds via the accumulation of Eshelby events, i.e. local rearrangements that create long-ranged and anisotropic stresses in the surrounding medium. Such events must be characterized using tensorial observables and we construct an analytical framework to probe their correlations using local stress data. By analyzing numerical simulations, we then demonstrate that events are power-law correlated in space, with a time-dependent amplitude which peaks at the alpha relaxation time τ(α). This effect, which becomes stronger near the glass transition, results from the increasingly important role of local stress fluctuations in facilitating relaxation events. Our finding precludes the existence of any length scale beyond which the relaxation process decorrelates.
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Affiliation(s)
- Anaël Lemaître
- Université Paris-Est, Laboratoire Navier (UMR 8205), CNRS, ENPC, IFSTTAR, 2 allée Képler, F-77420 Marne-la-Valle, France
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26
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Smessaert A, Rottler J. Structural relaxation in glassy polymers predicted by soft modes: a quantitative analysis. SOFT MATTER 2014; 10:8533-8541. [PMID: 25241966 DOI: 10.1039/c4sm01438c] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We present a quantitative analysis of the correlation between quasi-localized, low energy vibrational modes and structural relaxation events in computer simulations of a quiescent, thermal polymer glass. Our results extend previous studies on glass forming binary mixtures in 2D, and show that the soft modes identify regions that undergo irreversible rearrangements with up to 7 times the average probability. We study systems in the supercooled- and aging-regimes and discuss temperature- as well as age-dependence of the correlation. In addition to the location of rearrangements, we find that soft modes also predict their direction on the molecular level. The soft regions are long lived structural features, and the observed correlations vanish only after >50% of the system has undergone rearrangements.
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Affiliation(s)
- Anton Smessaert
- Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, B.C. V6T 1Z1, Canada.
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27
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Shang BS, Li MZ, Yao YG, Lu YJ, Wang WH. Evolution of atomic rearrangements in deformation in metallic glasses. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 90:042303. [PMID: 25375490 DOI: 10.1103/physreve.90.042303] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Indexed: 06/04/2023]
Abstract
Atomic rearrangements induced by shear stress are fundamental for understanding deformation mechanisms in metallic glasses (MGs). Using molecular dynamic simulation, the atomic rearrangements characterized by nonaffine displacements (NADs) and their spatial distribution and evolution with tensile stress in Cu50Zr50 MG were investigated. It was found that in the elastic regime the atomic rearrangements with the largest NADs are relatively homogeneous in space, but exhibit strong spatial correlation, become localized and inhomogeneous, and form large clusters as strain increases, which may facilitate the so-called shear transformation zones. Furthermore, initially they prefer to take place around Cu atoms which have more nonicosahedral configurations. As strain increases, the preference decays and disappears in the plastic regime. The atomic rearrangements with the smallest NADs are preferentially located around Cu atoms, too, but with more icosahedral or icosahedral-like atomic configurations. The preference is maintained in the whole deformation process. In contrast, the atomic rearrangements with moderate NADs distribute homogeneously, and do not show explicit preference or spatial correlation, acting as matrix during deformation. Among the atomic rearrangements with different NADs, those with largest and smallest NADs are nearest neighbors initially, but separating with increasing strain, while those with largest and moderate NADs always avoid to each other. The correlations in the fluctuations of the NADs confirm the long-range strain correlation and the scale-free characteristic of NADs in both elastic and plastic deformation, which suggests a universality of the scaling in the plastic flow in MGs.
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Affiliation(s)
- B S Shang
- State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
| | - M Z Li
- Department of Physics, Renmin University of China, Beijing 100872, China
| | - Y G Yao
- School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Y J Lu
- School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - W H Wang
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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28
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Abstract
In a 3D model mimicking realistic Cu64Zr36 metallic glass, we uncovered a direct link between the quasi-localized low-frequency vibrational modes and the local atomic packing structure. We also demonstrate that quasi-localized soft modes correlate strongly with fertile sites for shear transformations: geometrically unfavored motifs constitute the most flexible local environments that encourage soft modes and high propensity for shear transformations, whereas local configurations preferred in this alloy, i.e., the full icosahedra (around Cu) and Z16 Kasper polyhedra (around Zr), contribute the least.
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