1
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Kamel SM, Daróczi L, Tóth LZ, Beke DL, Juárez GG, Cobo S, Salmon L, Molnár G, Bousseksou A. Acoustic emissions from spin crossover complexes. JOURNAL OF MATERIALS CHEMISTRY. C 2024; 12:5757-5765. [PMID: 38680543 PMCID: PMC11044199 DOI: 10.1039/d4tc00495g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 03/19/2024] [Indexed: 05/01/2024]
Abstract
Acoustic emission from the compounds [Fe(HB(tz)3)2] and [Fe(Htrz)(trz)2]BF4 was detected during the thermally induced spin transition and is correlated with simultaneously recorded calorimetric signals. We ascribe this phenomenon to elastic waves produced by microstructural and volume changes accompanying the spin transition. Despite the perfect reversibility of the spin state switching (seen by the calorimeter), the acoustic emission activity decreases for successive thermal cycles, revealing thus irreversible microstructural evolution of the samples. The acoustic emission signal amplitude and energy probability distribution functions followed power-law behavior and the characteristic exponents were found to be similar for the two samples both on heating and cooling, indicating the universal character, which is further substantiated by the well scaled average temporal shapes of the avalanches.
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Affiliation(s)
- Sarah M Kamel
- Department of Solid State Physics, Doctoral School of Physics, University of Debrecen P.O. Box 2 H-4010 Debrecen Hungary
- Physics Department, Faculty of Science Ain Shams University, Abbassia 11566 Cairo Egypt
| | - Lajos Daróczi
- Department of Solid State Physics, Doctoral School of Physics, University of Debrecen P.O. Box 2 H-4010 Debrecen Hungary
| | - László Z Tóth
- Department of Solid State Physics, Doctoral School of Physics, University of Debrecen P.O. Box 2 H-4010 Debrecen Hungary
| | - Dezső L Beke
- Department of Solid State Physics, Doctoral School of Physics, University of Debrecen P.O. Box 2 H-4010 Debrecen Hungary
| | - Gerardo Gutiérrez Juárez
- Departamento de Ingeniería Física, División de Ciencias e Ingenierías, Universidad de Guanajuato-Campus León, Loma del Bosque 103, Loma del Campestre 37150 León Gto. Mexico
| | - Saioa Cobo
- LCC, CNRS & University of Toulouse, 205 route de Narbonne 31077 Toulouse France
| | - Lionel Salmon
- LCC, CNRS & University of Toulouse, 205 route de Narbonne 31077 Toulouse France
| | - Gábor Molnár
- LCC, CNRS & University of Toulouse, 205 route de Narbonne 31077 Toulouse France
| | - Azzedine Bousseksou
- LCC, CNRS & University of Toulouse, 205 route de Narbonne 31077 Toulouse France
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2
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Shekh Alshabab S, Markert B, Bamer F. Criticality in the fracture of silica glass: Insights from molecular mechanics. Phys Rev E 2024; 109:034110. [PMID: 38632794 DOI: 10.1103/physreve.109.034110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 02/02/2024] [Indexed: 04/19/2024]
Abstract
The universality of avalanches characterizing the inelastic response of disordered materials has the potential to bridge the gap from micro to macroscale. In this study, we explore the statistics and the scaling behavior of avalanches occurring during the fracture process in silica glass using molecular mechanics. We introduce a robust method for capturing and quantifying these avalanches, allowing us to perform rigorous statistical analyses, revealing universal power laws associated with critical phenomena. The influence of an initial crack is explored, observing deviations from mean-field predictions while maintaining the property of criticality. However, the avalanche exponents in the unnotched samples are predicted correctly by the mean-field depinning model. Furthermore, we investigate the strain-dependent probability density function, its cutoff function, and the interrelation between the critical exponents. Finally, we unveil distinct scaling behavior for small and large avalanches of the crack growth, shedding light on the underlying fracture mechanisms in silica glass.
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Affiliation(s)
| | - Bernd Markert
- Institute of General Mechanics, RWTH Aachen University, 52062 Aachen, Germany
| | - Franz Bamer
- Institute of General Mechanics, RWTH Aachen University, 52062 Aachen, Germany
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3
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Liang J, Yang D, Xiao Y, Chen S, Dadap JI, Rottler J, Ye Z. Shear Strain-Induced Two-Dimensional Slip Avalanches in Rhombohedral MoS 2. NANO LETTERS 2023; 23:7228-7235. [PMID: 37358360 DOI: 10.1021/acs.nanolett.3c01487] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/27/2023]
Abstract
Slip avalanches are ubiquitous phenomena occurring in three-dimensional materials under shear strain, and their study contributes immensely to our understanding of plastic deformation, fragmentation, and earthquakes. So far, little is known about the role of shear strain in two-dimensional (2D) materials. Here we show some evidence of 2D slip avalanches in exfoliated rhombohedral MoS2, triggered by shear strain near the threshold level. Utilizing interfacial polarization in 3R-MoS2, we directly probe the stacking order in multilayer flakes and discover a wide variety of polarization domains with sizes following a power-law distribution. These findings suggest that slip avalanches can occur during the exfoliation of 2D materials, and the stacking orders can be changed via shear strain. Our observation has far-reaching implications for the development of new materials and technologies, where precise control over the atomic structure of these materials is essential for optimizing their properties as well as for our understanding of fundamental physical phenomena.
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Affiliation(s)
- Jing Liang
- Department of Physics and Astronomy, The University of British Columbia, Vancouver, BC V6T 1Z1, Canada
- Quantum Matter Institute, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Dongyang Yang
- Department of Physics and Astronomy, The University of British Columbia, Vancouver, BC V6T 1Z1, Canada
- Quantum Matter Institute, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Yunhuan Xiao
- Department of Physics and Astronomy, The University of British Columbia, Vancouver, BC V6T 1Z1, Canada
- Quantum Matter Institute, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Sean Chen
- Department of Physics and Astronomy, The University of British Columbia, Vancouver, BC V6T 1Z1, Canada
- Quantum Matter Institute, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Jerry I Dadap
- Department of Physics and Astronomy, The University of British Columbia, Vancouver, BC V6T 1Z1, Canada
- Quantum Matter Institute, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Joerg Rottler
- Department of Physics and Astronomy, The University of British Columbia, Vancouver, BC V6T 1Z1, Canada
- Quantum Matter Institute, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Ziliang Ye
- Department of Physics and Astronomy, The University of British Columbia, Vancouver, BC V6T 1Z1, Canada
- Quantum Matter Institute, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
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4
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Tóth LZ, Bronstein E, Daróczi L, Shilo D, Beke DL. Scaling of Average Avalanche Shapes for Acoustic Emission during Jerky Motion of Single Twin Boundary in Single-Crystalline Ni 2MnGa. MATERIALS (BASEL, SWITZERLAND) 2023; 16:2089. [PMID: 36903204 PMCID: PMC10004433 DOI: 10.3390/ma16052089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 02/28/2023] [Accepted: 03/01/2023] [Indexed: 06/18/2023]
Abstract
Temporal average shapes of crackling noise avalanches, U(t) (U is the detected parameter proportional to the interface velocity), have self-similar behavior, and it is expected that by appropriate normalization, they can be scaled together according to a universal scaling function. There are also universal scaling relations between the avalanche parameters (amplitude, A, energy, E, size (area), S, and duration, T), which in the mean field theory (MFT) have the form E∝A3, S∝A2, S∝T2. Recently, it turned out that normalizing the theoretically predicted average U(t) function at a fixed size, U(t)=atexp-bt2 (a and b are non-universal, material-dependent constants) by A and the rising time, R, a universal function can be obtained for acoustic emission (AE) avalanches emitted during interface motions in martensitic transformations, using the relation R~A1-φ too, where φ is a mechanism-dependent constant. It was shown that φ also appears in the scaling relations E~A3-φ and S~A2-φ, in accordance with the enigma for AE, that the above exponents are close to 2 and 1, respectively (in the MFT limit, i.e., with φ= 0, they are 3 and 2, respectively). In this paper, we analyze these properties for acoustic emission measurements carried out during the jerky motion of a single twin boundary in a Ni50Mn28.5Ga21.5 single crystal during slow compression. We show that calculating from the above-mentioned relations and normalizing the time axis of the average avalanche shapes with A1-φ, and the voltage axis with A, the averaged avalanche shapes for the fixed area are well scaled together for different size ranges. These have similar universal shapes as those obtained for the intermittent motion of austenite/martensite interfaces in two different shape memory alloys. The averaged shapes for a fixed duration, although they could be acceptably scaled together, showed a strong positive asymmetry (the avalanches decelerate much slower than they accelerate) and thus did not show a shape reminiscent of an inverted parabola, predicted by the MFT. For comparison, the above scaling exponents were also calculated from simultaneously measured magnetic emission data. It was obtained that the φ values are in accordance with theoretical predictions going beyond the MFT, but the AE results for φ are characteristically different from these, supporting that the well-known enigma for AE is related to this deviation.
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Affiliation(s)
- László Z. Tóth
- Department of Solid State Physics, University of Debrecen, P.O. Box 400, H-4002 Debrecen, Hungary
| | - Emil Bronstein
- Faculty of Mechanical Engineering, Technion—Israel Institute of Technology, Haifa 3200003, Israel
| | - Lajos Daróczi
- Department of Solid State Physics, University of Debrecen, P.O. Box 400, H-4002 Debrecen, Hungary
| | - Doron Shilo
- Faculty of Mechanical Engineering, Technion—Israel Institute of Technology, Haifa 3200003, Israel
| | - Dezső L. Beke
- Department of Solid State Physics, University of Debrecen, P.O. Box 400, H-4002 Debrecen, Hungary
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Richard D, Elgailani A, Vandembroucq D, Manning ML, Maloney CE. Mechanical excitation and marginal triggering during avalanches in sheared amorphous solids. Phys Rev E 2023; 107:034902. [PMID: 37072969 DOI: 10.1103/physreve.107.034902] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 02/26/2023] [Indexed: 04/20/2023]
Abstract
We study plastic strain during individual avalanches in overdamped particle-scale molecular dynamics (MD) and mesoscale elastoplastic models (EPM) for amorphous solids sheared in the athermal quasistatic limit. We show that the spatial correlations in plastic activity exhibit a short length scale that grows as t^{3/4} in MD and ballistically in EPM, which is generated by mechanical excitation of nearby sites not necessarily close to their stability thresholds, and a longer lengthscale that grows diffusively for both models and is associated with remote marginally stable sites. These similarities in spatial correlations explain why simple EPMs accurately capture the size distribution of avalanches observed in MD, though the temporal profiles and dynamical critical exponents are quite different.
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Affiliation(s)
- D Richard
- Institute for Theoretical Physics, University of Amsterdam, Science Park 904, Amsterdam, Netherlands
- Department of Physics and BioInspired Institute, Syracuse University, Syracuse, New York 13244, USA
- Univiversité Grenoble Alpes, CNRS, LIPhy, 38000 Grenoble, France
| | - A Elgailani
- Northeastern University, Boston, Massachusetts 02115, USA
| | - D Vandembroucq
- PMMH, CNRS UMR 7636, ESPCI Paris, PSL University, Sorbonne Université, Université de Paris, F-75005 Paris, France
| | - M L Manning
- Department of Physics and BioInspired Institute, Syracuse University, Syracuse, New York 13244, USA
| | - C E Maloney
- Northeastern University, Boston, Massachusetts 02115, USA
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6
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Experimental evidence that shear bands in metallic glasses nucleate like cracks. Sci Rep 2022; 12:18499. [PMID: 36323768 PMCID: PMC9630419 DOI: 10.1038/s41598-022-22548-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 10/17/2022] [Indexed: 11/13/2022] Open
Abstract
Highly time-resolved mechanical measurements, modeling, and simulations show that large shear bands in bulk metallic glasses nucleate in a manner similar to cracks. When small slips reach a nucleation size, the dynamics changes and the shear band rapidly grows to span the entire sample. Smaller nucleation sizes imply lower ductility. Ductility can be increased by increasing the nucleation size relative to the maximum ("cutoff") shear band size at the upper edge of the power law scaling range of their size distribution. This can be achieved in three ways: (1) by increasing the nucleation size beyond this cutoff size of the shear bands, (2) by keeping all shear bands smaller than the nucleation size, or (3) by choosing a sample size smaller than the nucleation size. The discussed methods can also be used to rapidly order metallic glasses according to ductility.
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7
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Tóth LZ, Daróczi L, Elrasasi TY, Beke DL. Clustering Characterization of Acoustic Emission Signals Belonging to Twinning and Dislocation Slip during Plastic Deformation of Polycrystalline Sn. MATERIALS (BASEL, SWITZERLAND) 2022; 15:6696. [PMID: 36234037 PMCID: PMC9572014 DOI: 10.3390/ma15196696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/21/2022] [Accepted: 09/22/2022] [Indexed: 06/16/2023]
Abstract
Results of acoustic emission (AE) measurements, carried out during plastic deformation of polycrystalline Sn samples, are analyzed by the adaptive sequential k-means method. The acoustic avalanches, originating from different sources, are separated on the basis of their spectral properties, that is, sorted into clusters, presented both on the so-called feature space (energy-median frequency plot) and on the power spectral density (PSD) curves. We found that one cluster in every measurement belongs to background vibrations, while the remaining ones are clearly attributed to twinning as well as dislocation slips at −30 °C and 25 °C, respectively. Interestingly, fingerprints of the well-known “ringing” of AE signals are present in different weights on the PSD curves. The energy and size distributions of the avalanches, corresponding to twinning and dislocation slips, show a bit different power-law exponents from those obtained earlier by fitting all AE signals without cluster separation. The maximum-likelihood estimation of the avalanche energy (ε) and size (τ) exponents provide ε=1.57±0.05 (at −30 °C) and ε=1.35±0.1 (at 25 °C), as well as τ=1.92±0.05 (at −30 °C) and τ= 1.55±0.1 (at 25 °C). The clustering analysis provides not only a manner to eliminate the background noise, but the characteristic avalanche shapes are also different for the two mechanisms, as it is visible on the PSD curves. Thus, we have illustrated that this clustering analysis is very useful in discriminating between different AE sources and can provide more realistic estimates, for example, for the characteristic exponents as compared to the classical hit-based approach where the exponents reflect an average value, containing hits from the low-frequency mechanical vibrations of the test machine, too.
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Affiliation(s)
- László Z. Tóth
- Department of Solid State Physics, University of Debrecen, P.O. Box 400, H-4002 Debrecen, Hungary
| | - Lajos Daróczi
- Department of Solid State Physics, University of Debrecen, P.O. Box 400, H-4002 Debrecen, Hungary
| | - Tarek Y. Elrasasi
- Department of Physics, Faculty of Science, Benha University, Benha 13518, Egypt
| | - Dezső L. Beke
- Department of Solid State Physics, University of Debrecen, P.O. Box 400, H-4002 Debrecen, Hungary
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8
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Du F, Alghamdi S, Yang J, Huston D, Tan T. Interfacial Mechanical Behavior in Nacre of Red Abalone and Other Shells: A Review. ACS Biomater Sci Eng 2022. [PMID: 35959691 DOI: 10.1021/acsbiomaterials.2c00080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Interfaces between nacreous tablets are crucial to the outstanding mechanical properties of nacre in natural shells. Excellent research has been conducted to probe the effect of interfaces on strength and toughness of nacre, providing critical guidelines for the design of human-made laminated composites. This article reviews recent studies on interfacial mechanical behavior of nacre in red abalone and other shells, including experimental methods, analytical and numerical modeling. The discussions focus on the mechanical properties of dry and hydrated nacreous microstructures. The review concludes with discussions on representative studies of nacre-like composites with interfaces tuned using multiple approaches, and provides an outlook on improving the performance of composites with better interfacial controls.
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Affiliation(s)
- Fen Du
- Department of Mechanical Engineering, Vermont Technical College, Randolph Center, Vermont 05061, United States.,Department of Mechanical Engineering, Beijing Institute of Technology, Zhuhai 519082, China
| | - Saleh Alghamdi
- Department of Civil Engineering, College of Engineering, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia
| | - Jie Yang
- Department of Physics, University of Vermont, Burlington, Vermont 05405, United States
| | - Dryver Huston
- Department of Mechanical Engineering, University of Vermont, Burlington, Vermont 05405, United States
| | - Ting Tan
- Department of Civil Engineering, Sun Yat-Sen University, Zhuhai 519082, China.,Department of Civil and Environment Engineering, University of Vermont, Burlington, Vermont 05405, United States
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9
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Cui S, Liu H, Peng H. Anisotropic correlations of plasticity on the yielding of metallic glasses. Phys Rev E 2022; 106:014607. [PMID: 35974506 DOI: 10.1103/physreve.106.014607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 07/07/2022] [Indexed: 06/15/2023]
Abstract
We report computer simulations on the shear deformation of CuZr metallic glasses at zero and room temperatures. Shear bands emerge in athermal alloys at strain γ_{c}, with a finite-size effect found. The correlation of nonaffine displacement exhibits an exponential decay even after yielding in thermal alloys, but transits to a power law at γ>γ_{c} in athermal ones. The algebraic exponent is around -1 for the decay inside shear bands, consistent with the theoretical prediction in random elastic media. We quantify the anisotropic correlation with harmonic projection, finding the spectrum is weak in the exponential-decay regime, while it displays a strong polar and quadrupolar symmetry in the power-law regime. The nonvanishing quadrupolar symmetry at long distance signifies the nonlocality of plastic correlation in the athermal alloys. In contrast, the plastic correlation was found to be isotropic and localized at the yielding in the thermal alloys without shear bands.
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Affiliation(s)
- Shiheng Cui
- School of Materials Science and Engineering, Central South University, 932 South Lushan Road, Changsha 410083, China
| | - Huashan Liu
- School of Materials Science and Engineering, Central South University, 932 South Lushan Road, Changsha 410083, China
| | - Hailong Peng
- School of Materials Science and Engineering, Central South University, 932 South Lushan Road, Changsha 410083, China
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10
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Denouement of the Energy-Amplitude and Size-Amplitude Enigma for Acoustic-Emission Investigations of Materials. MATERIALS 2022; 15:ma15134556. [PMID: 35806681 PMCID: PMC9267350 DOI: 10.3390/ma15134556] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 06/17/2022] [Accepted: 06/24/2022] [Indexed: 02/04/2023]
Abstract
There are many systems producing crackling noise (avalanches) in materials. Temporal shapes of avalanches, U(t) (U is the detected voltage signal, t is the time), have self-similar behaviour and the normalized U(t) function (e.g., dividing both the values of U and t by S1/2, where S is the avalanche area), averaged for fixed S, should be the same, independently of the type of materials or avalanche mechanisms. However, there are experimental evidences that the temporal shapes of avalanches do not scale completely in a universal way. The self-similarity also leads to universal power-law-scaling relations, e.g., between the energy, E, and the peak amplitude, Am, or between S and Am. There are well-known enigmas, where the above exponents in acoustic emission measurements are rather close to 2 and 1, respectively, instead of E~Am3 and S~Am2, obtained from the mean field theory, MFT. We show, using a theoretically predicted averaged function for the fixed avalanche area, U(t)=atexp(−bt2) (where a and b are non-universal, material-dependent constants), that the scaling exponents can be different from the MFT values. Normalizing U by Am and t by tm (the time belonging to the Am: rise time), we obtain tm~Am1−φ (the MFT values can be obtained only if φ would be zero). Here, φ is expected to be material-independent and to be the same for the same mechanism. Using experimental results on martensitic transformations in two different shape-memory single-crystals, φ = 0.8 ± 0.1 was obtained (φ is the same for both alloys). Thus, dividing U by Am as well as t by Am1−φ (~tm) leads to the same common, normalized temporal shape for different, fixed values of S. This normalization can also be used in general for other experimental results (not only for acoustic emission), which provide information about jerky noises in materials.
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11
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Bhaumik H, Foffi G, Sastry S. Avalanches, Clusters, and Structural Change in Cyclically Sheared Silica Glass. PHYSICAL REVIEW LETTERS 2022; 128:098001. [PMID: 35302798 DOI: 10.1103/physrevlett.128.098001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 01/14/2022] [Accepted: 02/09/2022] [Indexed: 06/14/2023]
Abstract
We investigate avalanches and clusters associated with plastic rearrangements and the nature of structural change in the prototypical strong glass, silica, computationally. We perform a detailed analysis of avalanches, and of spatially disconnected clusters that constitute them, for a wide range of system sizes. Although qualitative aspects of yielding in silica are similar to other glasses, the statistics of clusters exhibits significant differences, which we associate with differences in local structure. Across the yielding transition, anomalous structural change and densification, associated with a suppression of tetrahedral order, is observed to accompany strain localization.
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Affiliation(s)
- Himangsu Bhaumik
- Jawaharlal Nehru Center for Advanced Scientific Research, Jakkur Campus, Bengaluru 560064, India
| | - Giuseppe Foffi
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405 Orsay, France
| | - Srikanth Sastry
- Jawaharlal Nehru Center for Advanced Scientific Research, Jakkur Campus, Bengaluru 560064, India
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12
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Rizzardi Q, McElfresh C, Sparks G, Stauffer DD, Marian J, Maaß R. Mild-to-wild plastic transition is governed by athermal screw dislocation slip in bcc Nb. Nat Commun 2022; 13:1010. [PMID: 35197454 PMCID: PMC8866410 DOI: 10.1038/s41467-022-28477-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 01/07/2022] [Indexed: 11/29/2022] Open
Abstract
Plastic deformation in crystals is mediated by the motion of line defects known as dislocations. For decades, dislocation activity has been treated as a homogeneous, smooth continuous process. However, it is now recognized that plasticity can be determined by long-range correlated and intermittent collective dislocation processes, known as avalanches. Here we demonstrate in body-centered cubic Nb how the long-range and scale-free dynamics at room temperature are progressively quenched out with decreasing temperature, eventually revealing intermittency with a characteristic length scale that approaches the Burgers vector itself. Plasticity is shown to be bimodal across the studied temperature regime, with conventional thermally-activated smooth plastic flow (‘mild’) coexisting with sporadic bursts (‘wild’) controlled by athermal screw dislocation activity, thereby violating the classical notion of temperature-dependent screw dislocation motion at low temperatures. An abrupt increase of the athermal avalanche component is identified at the critical temperature of the material. Our results indicate that plasticity at any scale can be understood in terms of the coexistence of these mild and wild modes of deformation, which could help design better alloys by suppressing one of the two modes in desired temperature windows. Recent studies have recognized that plasticity in metals can be controlled by dislocation avalanches. Here the authors examine temperature-dependent microplasticity in bcc Nb and reveal the dominance of athermal screw dislocation activity during intermittent slip.
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Affiliation(s)
- Q Rizzardi
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - C McElfresh
- Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - G Sparks
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - D D Stauffer
- Bruker Nano Surfaces & Metrology, Hysitron Products, Eden Prairie, MN, 55344, USA
| | - J Marian
- Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - R Maaß
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA. .,Federal Institute of Materials Research and Testing (BAM), Unter den Eichen 87, 12205, Berlin, Germany.
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13
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Baró J, Pouragha M, Wan R, Davidsen J. Quasistatic kinetic avalanches and self-organized criticality in deviatorically loaded granular media. Phys Rev E 2021; 104:024901. [PMID: 34525539 DOI: 10.1103/physreve.104.024901] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 07/08/2021] [Indexed: 11/07/2022]
Abstract
The behavior of granular media under quasistatic loading has recently been shown to attain a stable evolution state corresponding to a manifold in the space of micromechanical variables. This state is characterized by sudden transitions between metastable jammed states, involving the partial micromechanical rearrangement of the granular medium. Using numerical simulations of two-dimensional granular media under quasistatic biaxial compression, we show that the dynamics in the stable evolution state is characterized by scale-free avalanches well before the macromechanical stationary flow regime traditionally linked to a self-organized critical state. This, together with the nonuniqueness and the nonmonotony of macroscopic deformation curves, suggests that the statistical avalanche properties and the susceptibilities of the system cannot be reduced to a function of the macromechanical state. The associated scaling exponents are nonuniversal and depend on the interactions between particles. For stiffer particles (or samples at low confining pressure) we find distributions of avalanche properties compatible with the predictions of mean-field theory. The scaling exponents decrease below the mean-field values for softer interactions between particles. These lower exponents are consistent with observations for amorphous solids at their critical point. We specifically discuss the relationship between microscopic and macroscopic variables, including the relation between the external stress drop and the internal potential energy released during kinetic avalanches.
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Affiliation(s)
- Jordi Baró
- Department of Physics and Astronomy, University of Calgary, 2500 University Drive NW Calgary, Alberta, Canada T2N 1N4.,Centre for Mathematical Research, Campus de Bellaterra, Edifici C, 08193 Bellaterra, Barcelona, Spain
| | - Mehdi Pouragha
- Civil Engineering Department, University of Calgary, 2500 University Drive NW Calgary, Alberta, Canada T2N 1N4.,Department of Civil and Environmental Engineering, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, Canada K1S 5B6
| | - Richard Wan
- Civil Engineering Department, University of Calgary, 2500 University Drive NW Calgary, Alberta, Canada T2N 1N4
| | - Jörn Davidsen
- Department of Physics and Astronomy, University of Calgary, 2500 University Drive NW Calgary, Alberta, Canada T2N 1N4.,Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, Canada T2N 4N1
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14
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Oyama N, Mizuno H, Ikeda A. Unified view of avalanche criticality in sheared glasses. Phys Rev E 2021; 104:015002. [PMID: 34412287 DOI: 10.1103/physreve.104.015002] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 06/14/2021] [Indexed: 11/07/2022]
Abstract
Plastic events in sheared glasses are considered an example of so-called avalanches, whose sizes obey a power-law probability distribution with the avalanche critical exponent τ. Although the so-called mean-field depinning (MFD) theory predicts a universal value of this exponent, τ_{MFD}=1.5, such a simplification is now known to connote qualitative disagreement with realistic systems. Numerically and experimentally, different values of τ have been reported depending on the literature. Moreover, in the elastic regime, it has been noted that the critical exponent can be different from that in the steady state, and even criticality itself is a matter of debate. Because these confusingly varying results have been reported under different setups, our knowledge of avalanche criticality in sheared glasses is greatly limited. To gain a unified understanding, in this work, we conduct a comprehensive numerical investigation of avalanches in Lennard-Jones glasses under athermal quasistatic shear. In particular, by excluding the ambiguity and arbitrariness that has crept into the conventional measurement schemes, we achieve high-precision measurement and demonstrate that the exponent τ in the steady state follows the prediction of MFD theory, τ_{MFD}=1.5. Our results also suggest that there are two qualitatively different avalanche events. This binariness leads to the nonuniversal behavior of the avalanche size distribution and is likely to be the cause of the varying values of τ reported thus far. To investigate the dependence of criticality and universality on applied shear, we further study the statistics of avalanches in the elastic regime and the ensemble of the first avalanche event in different samples, which provide information about the unperturbed system. We show that while the unperturbed system is indeed off-critical, criticality gradually develops as shear is applied. The degree of criticality is encoded in the fractal dimension of the avalanches, which starts from zero in the off-critical unperturbed state and saturates in the steady state. Moreover, the critical exponent τ is consistent with the prediction of the MFD τ_{MFD} universally, regardless of the amount of applied shear, once the system becomes critical.
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Affiliation(s)
- Norihiro Oyama
- Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Tokyo 153-8902, Japan.,Mathematics for Advanced Materials-OIL, AIST, Sendai 980-8577, Japan
| | - Hideyuki Mizuno
- Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Tokyo 153-8902, Japan
| | - Atsushi Ikeda
- Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Tokyo 153-8902, Japan.,Research Center for Complex Systems Biology, Universal Biology Institute, The University of Tokyo, Komaba, Tokyo 153-8902, Japan
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15
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Saitoh K. The role of friction in statistics and scaling laws of avalanches. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2021; 44:85. [PMID: 34165652 DOI: 10.1140/epje/s10189-021-00089-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 06/14/2021] [Indexed: 06/13/2023]
Abstract
We investigate statistics and scaling laws of avalanches in two-dimensional frictional particles by numerical simulations. We find that the critical exponent for avalanche size distributions is governed by microscopic friction between the particles in contact, where the exponent is larger and closer to mean-field predictions if the friction coefficient is finite. We reveal that microscopic "slips" between frictional particles induce numerous small avalanches which increase the slope, as well as the power-law exponent, of avalanche size distributions. We also analyze statistics and scaling laws of the avalanche duration and maximum stress drop rates, and examine power spectra of stress drop rates. Our numerical results suggest that the microscopic friction is a key ingredient of mean-field descriptions and plays a crucial role in avalanches observed in real materials.
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Affiliation(s)
- Kuniyasu Saitoh
- Department of Physics, Faculty of Science, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-ku, Kyoto, 603-8555, Japan.
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16
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Clemmer JT, Salerno KM, Robbins MO. Criticality in sheared, disordered solids. I. Rate effects in stress and diffusion. Phys Rev E 2021; 103:042605. [PMID: 34005889 DOI: 10.1103/physreve.103.042605] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 03/16/2021] [Indexed: 11/07/2022]
Abstract
Rate effects in sheared disordered solids are studied using molecular dynamics simulations of binary Lennard-Jones glasses in two and three dimensions. In the quasistatic (QS) regime, systems exhibit critical behavior: the magnitudes of avalanches are power-law distributed with a maximum cutoff that diverges with increasing system size L. With increasing rate, systems move away from the critical yielding point and the average flow stress rises as a power of the strain rate with exponent 1/β, the Herschel-Bulkley exponent. Finite-size scaling collapses of the stress are used to measure β as well as the exponent ν which characterizes the divergence of the correlation length. The stress and kinetic energy per particle experience fluctuations with strain that scale as L^{-d/2}. As the largest avalanche in a system scales as L^{α}, this implies α<d/2. The diffusion rate of particles diverges as a power of decreasing rate before saturating in the QS regime. A scaling theory for the diffusion is derived using the QS avalanche rate distribution and generalized to the finite strain rate regime. This theory is used to collapse curves for different system sizes and confirm β/ν.
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Affiliation(s)
- Joel T Clemmer
- Sandia National Laboratories, Albuquerque, New Mexico 87123, USA
| | | | - Mark O Robbins
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
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17
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Tsai JCJ, Huang GH, Tsai CE. Signature of Transition between Granular Solid and Fluid: Rate-Dependent Stick Slips in Steady Shearing. PHYSICAL REVIEW LETTERS 2021; 126:128001. [PMID: 33834824 DOI: 10.1103/physrevlett.126.128001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 11/04/2020] [Accepted: 01/28/2021] [Indexed: 06/12/2023]
Abstract
Despite extensive studies on either smooth granular-fluid flow or the solidlike deformation at the slow limit, the change between these two extremes remains largely unexplored. By systematically investigating the fluctuations of tightly packed grains under steady shearing, we identify a transition zone with prominent stick-slip avalanches. We establish a state diagram, and propose a new dimensionless shear rate based on the speed dependence of interparticle friction and particle size. With fluid-immersed particles confined in a fixed volume and forced to "flow" at viscous numbers J decades below reported values, we answer how a granular system can transition to the regime sustained by solid-to-solid friction that goes beyond existing paradigms based on suspension rheology.
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Affiliation(s)
| | - Guan-Hao Huang
- Institute of Physics, Academia Sinica, 11529 Taipei, Taiwan
| | - Cheng-En Tsai
- Institute of Physics, Academia Sinica, 11529 Taipei, Taiwan
- Department of Physics, National Central University, 320317 Chung-Li, Taiwan
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18
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A Review of the Serrated-Flow Phenomenon and Its Role in the Deformation Behavior of High-Entropy Alloys. METALS 2020. [DOI: 10.3390/met10081101] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
High-entropy alloys (HEAs) are a novel class of alloys that have many desirable properties. The serrated flow that occurs in high-entropy alloys during mechanical deformation is an important phenomenon since it can lead to significant changes in the microstructure of the alloy. In this article, we review the recent findings on the serration behavior in a variety of high-entropy alloys. Relationships among the serrated flow behavior, composition, microstructure, and testing condition are explored. Importantly, the mechanical-testing type (compression/tension), testing temperature, applied strain rate, and serration type for certain high-entropy alloys are summarized. The literature reveals that the serrated flow can be affected by experimental conditions such as the strain rate and test temperature. Furthermore, this type of phenomenon has been successfully modeled and analyzed, using several different types of analytical methods, including the mean-field theory formalism and the complexity-analysis technique. Importantly, the results of the analyses show that the serrated flow in HEAs consists of complex dynamical behavior. It is anticipated that this review will provide some useful and clarifying information regarding the serrated-flow mechanisms in this material system. Finally, suggestions for future research directions in this field are proposed, such as the effects of irradiation, additives (such as C and Al), the presence of nanoparticles, and twinning on the serrated flow behavior in HEAs.
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19
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Lin H, lu C, Wang HY, Dai LH. Non-trivial avalanches triggered by shear banding in compression of metallic glass foams. Proc Math Phys Eng Sci 2020. [DOI: 10.1098/rspa.2020.0186] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Ductile metallic glass foams (DMGFs) are a new type of structural material with a perfect combination of high strength and toughness. Owing to their disordered atomic-scale microstructures and randomly distributed macroscopic voids, the compressive deformation of DMGFs proceeds through multiple nanoscale shear bands accompanied by local fracture of cellular structures, which induces avalanche-like intermittences in stress–strain curves. In this paper, we present a statistical analysis, including distributions of avalanche size, energy dissipation, waiting times and aftershock sequence, on such a complex dynamic process, which is dominated by shear banding. After eliminating the influence of structural disorder, we demonstrate that, in contrast to the mean-field results of their brittle counterparts, scaling laws in DMGFs are characterized by different exponents. It is shown that the occurrence of non-trivial scaling behaviours is attributed to the localized plastic yielding, which effectively prevents the system from building up a long-range correlation. This accounts for the high structural stability and energy absorption performance of DMGFs. Furthermore, our results suggest that such shear banding dynamics introduce an additional characteristic time scale, which leads to a universal gamma distribution of waiting times.
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Affiliation(s)
- H. Lin
- State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
- School of Engineering Science, University of Chinese Academy of Sciences, Beijing 101408, People’s Republic of China
| | - C. lu
- School of Civil and Mechanical Engineering, Curtin University, Western Australia 6845, Australia
| | - H. Y. Wang
- State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
- School of Engineering Science, University of Chinese Academy of Sciences, Beijing 101408, People’s Republic of China
| | - L. H. Dai
- State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
- School of Engineering Science, University of Chinese Academy of Sciences, Beijing 101408, People’s Republic of China
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20
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Zhang L, Narayan RL, Sun BA, Yan TY, Ramamurty U, Eckert J, Zhang HF. Cooperative Shear in Bulk Metallic Glass Composites Containing Metastable β-Ti Dendrites. PHYSICAL REVIEW LETTERS 2020; 125:055501. [PMID: 32794839 DOI: 10.1103/physrevlett.125.055501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 06/22/2020] [Indexed: 06/11/2023]
Abstract
We report a novel plastic deformation mechanism of bulk metallic glass composites (BMGCs) containing metastable β-Ti dendrites. Plastic deformation of the BMGCs beyond the ultimate tensile strength is mediated by cooperative shear events, which comprise a shear band in the glassy matrix and a continuous ω-Ti band with a thickness of ∼10 nm in the β-Ti dendrite. The cooperative shear leads to serrated shear avalanches. The formation of narrow ω-Ti bands is caused by high local strain rates during the cooperative shear. The cooperative shear mechanism enriches the deformation mechanisms of BMGCs and also deepens the understanding of ω-Ti formation.
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Affiliation(s)
- L Zhang
- Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
| | - R L Narayan
- Department of Materials Science and Technology, Indian Institute of Technology Delhi, Delhi 110016, India
| | - B A Sun
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - T Y Yan
- Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
| | - U Ramamurty
- Department of Mechanical and Aerospace Engineering in Nanyang Technological University, Singapore 637331, Singapore
| | - J Eckert
- Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, A-8700 Leoben, Austria
- Department of Materials Science, Chair of Materials Physics, Montanuniversität Leoben, A-8700 Leoben, Austria
| | - H F Zhang
- Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
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21
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Alghamdi S, Liu Z, Du F, Yang J, Dahmen KA, Tan T. Sliding Avalanches Between Nacreous Tablets. NANO LETTERS 2020; 20:5024-5029. [PMID: 32511926 DOI: 10.1021/acs.nanolett.0c01148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Nacre, also known as mother of pearl, possesses extraordinary mechanical properties resulting from its intriguing hierarchical brick-and-mortar microstructures. Despite prior studies, interactions between nanoasperities during sliding still need to be elucidated. In this study, we measure slip events between nanograins of microlayers at high temporal resolution during torsion-induced sliding. We model the slips as avalanches caused by interactions of atoms on nanograin surfaces, from which power laws and scaling functions describing statistics and dynamics of slip events are studied. The largest avalanche occurs when nanograins leave each other after the maximum contact. The agreement between measurements and predictions shows that avalanches act essentially in the inhomogeneous sliding of nacreous tablets. Further insights into nanofriction provided in this work may lead to the development of nanoscale tribological systems.
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Affiliation(s)
- Saleh Alghamdi
- Department of Civil and Environmental Engineering, 33 Colchester Avenue, University of Vermont, Burlington, Vermont 05405, United States
- Department of Civil Engineering, Taif University, Taif 21944, Kingdom of Saudi Arabia
| | - Zhuang Liu
- Department of Mechanical Engineering, 33 Colchester Avenue, University of Vermont, Burlington, Vermont 05405, United States
| | - Fen Du
- Department of Mechanical Engineering, 124 Admin Drive, Vermont Technical College, Randolph Center, Vermont 05061, United States
| | - Jie Yang
- Department of Physics, 82 University Place, University of Vermont, Burlington, Vermont 05405, United States
| | - Karin A Dahmen
- Department of Physics and Institute of Condensed Matter Theory, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801, United States
| | - Ting Tan
- Department of Civil and Environmental Engineering, 33 Colchester Avenue, University of Vermont, Burlington, Vermont 05405, United States
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22
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McFaul LW, Sparks G, Sickle J, Uhl JT, Wright WJ, Maaß R, Dahmen KA. Applied-force oscillations in avalanche dynamics. Phys Rev E 2020; 101:053003. [PMID: 32575338 DOI: 10.1103/physreve.101.053003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 03/12/2020] [Indexed: 11/07/2022]
Abstract
Until now most studies of discrete plasticity have focused on systems that are assumed to be driven by a monotonically increasing force; in many real systems, however, the driving force includes damped oscillations or oscillations induced by the propagation of discrete events or "slip avalanches." In both cases, these oscillations may obscure the true dynamics. Here we effectively consider both cases by investigating the effects of damped oscillations in the external driving force on avalanche dynamics. We compare model simulations of slip avalanches under mean-field dynamics with observations in slip-avalanche experiments on slowly compressed micrometer-sized Au specimens using open-loop force control. The studies show very good agreement between simulations and experiments. We find that an oscillatory external driving force changes the average avalanche shapes only for avalanches with durations close to the period of oscillation of the external force. This effect on the avalanche shapes can be addressed in experiments by choosing suitable specimen dimensions so that the mechanical resonance does not interact with the avalanche dynamics. These results are important for the interpretation of avalanche experiments with built-in oscillators, and for the prediction and analysis of avalanche dynamics in systems with resonant vibrations.
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Affiliation(s)
- Louis W McFaul
- Department of Physics and Institute of Condensed Matter Theory, University of Illinois at Urbana Champaign, 1110 West Green Street, Urbana, Illinois 61801, USA
| | - Gregory Sparks
- Department of Materials Science and Engineering and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana Champaign, Urbana, Illinois 61801, USA
| | - Jordan Sickle
- Department of Physics and Institute of Condensed Matter Theory, University of Illinois at Urbana Champaign, 1110 West Green Street, Urbana, Illinois 61801, USA
| | - Jonathan T Uhl
- Department of Mechanical Engineering, One Dent Drive, Bucknell University, Lewisburg, Pennsylvania 17837, USA
| | - Wendelin J Wright
- Department of Mechanical Engineering, One Dent Drive, Bucknell University, Lewisburg, Pennsylvania 17837, USA.,Department of Chemical Engineering, One Dent Drive, Bucknell University, Lewisburg, Pennsylvania 17837, USA
| | - Robert Maaß
- Department of Materials Science and Engineering and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana Champaign, Urbana, Illinois 61801, USA
| | - Karin A Dahmen
- Department of Physics and Institute of Condensed Matter Theory, University of Illinois at Urbana Champaign, 1110 West Green Street, Urbana, Illinois 61801, USA
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23
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Relation Between the Defect Interactions and the Serration Dynamics in a Zr-Based Bulk Metallic Glass. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10113892] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
For this study, the effects of thermal annealing and compressive strain rate on the complexity of the serration behavior in a Zr-based bulk metallic glass (BMG) was investigated. Here, as-cast and thermally-annealed (300 °C, 1 week) Zr52.5Cu17.9Ni14.6Al10Ti5 BMG underwent room-temperature compression tests in the unconstrained condition at strain rates of 2 × 10−5 s−1 and 2 × 10−4 s−1. The complexity of the serrated flow was determined, using the refined composite multiscale entropy technique. Nanoindentation testing and X-ray diffraction characterization were performed to assess the changes in the microstructure and mechanical properties of the BMG that occurred during annealing. The results indicated that the BMG did not crystallize during annealing in the prescribed heating condition. Nanoindentation tests revealed that annealing led to a significant increase in the depth-dependent nanoindentation hardness and Young’s modulus, which were attributed to the structural relaxation in the glass. Furthermore, both annealing and an increased strain rate resulted in a marked enhancement in the complexity of the serrated flow during compression. It was concluded that the increase in the sample entropy with increasing strain rate is related to an increase in the number of defect interactions during the serrated flow.
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24
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Giuntoli A, Puosi F, Leporini D, Starr FW, Douglas JF. Predictive relation for the α-relaxation time of a coarse-grained polymer melt under steady shear. SCIENCE ADVANCES 2020; 6:eaaz0777. [PMID: 32494635 PMCID: PMC7182423 DOI: 10.1126/sciadv.aaz0777] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 01/27/2020] [Indexed: 05/14/2023]
Abstract
We examine the influence of steady shear on structural relaxation in a simulated coarse-grained unentangled polymer melt over a wide range of temperature and shear rates. Shear is found to progressively suppress the α-relaxation process observed in the intermediate scattering function, leading ultimately to a purely inertially dominated β-relaxation at high shear rates, a trend similar to increasing temperature. On the basis of a scaling argument emphasizing dynamic heterogeneity in cooled liquids and its alteration under material deformation, we deduce and validate a parameter-free scaling relation for both the structural relaxation time τα from the intermediate scattering function and the "stretching exponent" β quantifying the extent of dynamic heterogeneity over the entire range of temperatures and shear rates that we can simulate.
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Affiliation(s)
- Andrea Giuntoli
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersbug, Maryland 20899, USA
- Department of Physics, Wesleyan University, Middletown, Connecticut 06459, USA
| | - Francesco Puosi
- Dipartimento di Fisica “Enrico Fermi,” Università di Pisa, Largo B.Pontecorvo 3, I-56127 Pisa, Italy
| | - Dino Leporini
- Dipartimento di Fisica “Enrico Fermi,” Università di Pisa, Largo B.Pontecorvo 3, I-56127 Pisa, Italy
- IPCF-CNR, UOS Pisa, Italy
| | - Francis W. Starr
- Department of Physics, Wesleyan University, Middletown, Connecticut 06459, USA
| | - Jack F. Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersbug, Maryland 20899, USA
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25
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Shang B, Guan P, Barrat JL. Elastic avalanches reveal marginal behavior in amorphous solids. Proc Natl Acad Sci U S A 2020; 117:86-92. [PMID: 31843936 PMCID: PMC6955357 DOI: 10.1073/pnas.1915070117] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mechanical deformation of amorphous solids can be described as consisting of an elastic part in which the stress increases linearly with strain, up to a yield point at which the solid either fractures or starts deforming plastically. It is well established, however, that the apparent linearity of stress with strain is actually a proxy for a much more complex behavior, with a microscopic plasticity that is reflected in diverging nonlinear elastic coefficients. Very generally, the complex structure of the energy landscape is expected to induce a singular response to small perturbations. In the athermal quasistatic regime, this response manifests itself in the form of a scale-free plastic activity. The distribution of the corresponding avalanches should reflect, according to theoretical mean-field calculations [S. Franz and S. Spigler, Phys. Rev. E 95, 022139 (2017)], the geometry of phase space in the vicinity of a typical local minimum. In this work, we characterize this distribution for simple models of glass-forming systems, and we find that its scaling is compatible with the mean-field predictions for systems above the jamming transition. These systems exhibit marginal stability, and scaling relations that hold in the stationary state are examined and confirmed in the elastic regime. By studying the respective influence of system size and age, we suggest that marginal stability is systematic in the thermodynamic limit.
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Affiliation(s)
- Baoshuang Shang
- Beijing Computational Science Research Center, Beijing 100193, China
- Université Grenoble Alpes, CNRS, Laboratoire Interdisciplinaire de Physique (LIPhy), 38000 Grenoble, France
| | - Pengfei Guan
- Beijing Computational Science Research Center, Beijing 100193, China;
| | - Jean-Louis Barrat
- Université Grenoble Alpes, CNRS, Laboratoire Interdisciplinaire de Physique (LIPhy), 38000 Grenoble, France
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26
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Niiyama T, Wakeda M, Shimokawa T, Ogata S. Structural relaxation affecting shear-transformation avalanches in metallic glasses. Phys Rev E 2019; 100:043002. [PMID: 31770901 DOI: 10.1103/physreve.100.043002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Indexed: 11/07/2022]
Abstract
Avalanche behaviors, characterized by power-law statistics and structural relaxation that induces shear localization in amorphous plasticity, play an essential role in deciding the mechanical properties of amorphous metallic solids (i.e., metallic glasses). However, their interdependence is still not fully understood. To investigate the influence of structural relaxation on elementary avalanche behavior, we perform molecular-dynamics simulations for the shear deformation test of metallic glasses using two typical metallic-glass models comprising a less-relaxed (as-quenched) glass and a well-relaxed (well-aged) glass exhibiting a relatively homogeneous deformation and a shear-band-like heterogeneous deformation, respectively. The data on elementary avalanches obtained from both glass models follow the same power-law statistics with different maximum event sizes, and the well-relaxed glass shows shear localization. Evaluating the spatial correlation functions of the nonaffine squared displacements of atoms during each elementary avalanche event, we observe that the shapes of the elementary avalanche regions in the well-relaxed glasses tend to be anisotropic, whereas those in the less-relaxed glasses are relatively isotropic. Furthermore, we demonstrate that a temporal clustering in the direction of the avalanche propagation emerges, and a considerable correlation between the anisotropy and avalanche size exists in the well-relaxed glass model.
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Affiliation(s)
- Tomoaki Niiyama
- College of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Masato Wakeda
- Research Center for Structural Materials, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
| | - Tomotsugu Shimokawa
- Faculty of Mechanical Engineering, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Shigenobu Ogata
- Department of Mechanical Science and Bioengineering, Osaka University, Osaka 560-8531, Japan.,Center for Elements Strategy Initiative for Structural Materials (ESISM), Kyoto University, Sakyo, Kyoto 606-8501, Japan
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27
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Baldassarri A, Annunziata MA, Gnoli A, Pontuale G, Petri A. Breakdown of Scaling and Friction Weakening in Intermittent Granular Flow. Sci Rep 2019; 9:16962. [PMID: 31740801 PMCID: PMC6861274 DOI: 10.1038/s41598-019-53178-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 10/11/2019] [Indexed: 12/02/2022] Open
Abstract
Many materials are produced, processed and stored as grains, while granularity of matter can be crucial in triggering potentially catastrophic geological events like landslides, avalanches and earthquakes. The response of grain assemblies to shear stress is therefore of utmost relevance to both human and natural environment. At low shear rate a granular system flows intermittently by distinct avalanches. In such state the avalanche velocity in time is expected to follow a symmetrical and universal average behavior, whose dependence on the slip size reduces to a scale factor. Analyzing data from long lasting experiments, we observe a breakdown of this scaling: While in short slips velocity shows indeed a self-similar and symmetric profile, it does not in long slips. The investigation of frictional response in these different regimes evidences that this breakdown can be traced back to the onset of a friction weakening, which is of dynamical origin and can amplify instabilities exactly in this critical state, the most frequent state for natural hazards.
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Affiliation(s)
- A Baldassarri
- CNR - Istituto dei Sistemi Complessi, Dipartimento di Fisica, Università di Roma Sapienza, P.le A. Moro 2, I-00185, Roma, Italy
| | - M A Annunziata
- CNR - Istituto dei Sistemi Complessi, Dipartimento di Fisica, Università di Roma Sapienza, P.le A. Moro 2, I-00185, Roma, Italy
| | - A Gnoli
- CNR - Istituto dei Sistemi Complessi, Dipartimento di Fisica, Università di Roma Sapienza, P.le A. Moro 2, I-00185, Roma, Italy
| | - G Pontuale
- CNR - Istituto dei Sistemi Complessi, Dipartimento di Fisica, Università di Roma Sapienza, P.le A. Moro 2, I-00185, Roma, Italy
- Consiglio per la Ricerca in Agricoltura e l'Analisi dell'Economia Agraria (CREA) - Research Centre for Forestry and Woods, Via Santa Margherita 80, I-52100, Arezzo, Italy
| | - A Petri
- CNR - Istituto dei Sistemi Complessi, Dipartimento di Fisica, Università di Roma Sapienza, P.le A. Moro 2, I-00185, Roma, Italy.
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28
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Tyukodi B, Vandembroucq D, Maloney CE. Avalanches, thresholds, and diffusion in mesoscale amorphous plasticity. Phys Rev E 2019; 100:043003. [PMID: 31770912 DOI: 10.1103/physreve.100.043003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Indexed: 06/10/2023]
Abstract
We present results on a mesoscale model for amorphous matter in athermal, quasistatic (a-AQS), steady-state shear flow. In particular, we perform a careful analysis of the scaling with the lateral system size L of (i) statistics of individual relaxation events in terms of stress relaxation S, and individual event mean-squared displacement M, and the subsequent load increments Δγ, required to initiate the next event; (ii) static properties of the system encoded by x=σ_{y}-σ, the distance of local stress values from threshold; and (iii) long-time correlations and the emergence of diffusive behavior. For the event statistics, we find that the distribution of S is similar to, but distinct from, the distribution of M. We find a strong correlation between S and M for any particular event, with S∼M^{q} with q≈0.65. The exponent q completely determines the scaling exponents for P(M) given those for P(S). For the distribution of local thresholds, we find P(x) is analytic at x=0, and has a value P(x)|_{x=0}=p_{0} which scales with lateral system length as p_{0}∝L^{-0.6}. The size dependence of the average load increment 〈Δγ〉 appears to be asymptotically controlled by the plateau behavior of P(x) rather than by a subsequent apparent power-law behavior. Extreme value statistics arguments lead thus to a scaling relation between the exponents governing P(x) and those governing P(S). Finally, we study the long-time correlations via single-particle tracer statistics. The value of the diffusion coefficient is completely determined by 〈Δγ〉 and the scaling properties of P(M) (in particular from 〈M〉) rather than directly from P(S) as one might have naively guessed. Our results (i) further define the a-AQS universality class, (ii) clarify the relation between avalanches of stress relaxation and diffusive behavior, and (iii) clarify the relation between local threshold distributions and event statistics.
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Affiliation(s)
- Botond Tyukodi
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, Massachusetts 02115, USA
| | - Damien Vandembroucq
- PMMH, CNRS, ESPCI Paris, PSL University, Sorbonne Université, Université de Paris, F-75005 Paris, France
| | - Craig E Maloney
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, Massachusetts 02115, USA
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Potential energy landscape activations governing plastic flows in glass rheology. Proc Natl Acad Sci U S A 2019; 116:18790-18797. [PMID: 31484781 DOI: 10.1073/pnas.1907317116] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
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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Saitoh K, Oyama N, Ogushi F, Luding S. Transition rates for slip-avalanches in soft athermal disks under quasi-static simple shear deformations. SOFT MATTER 2019; 15:3487-3492. [PMID: 30849152 DOI: 10.1039/c8sm01966e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We study slip-avalanches in two-dimensional soft athermal disks by quasi-static simulations of simple shear deformations. Sharp drops in shear stress, or slip-avalanches, are observed intermittently during steady state. Such stress drops are caused by restructuring of the contact networks, accompanied by drastic changes of the interaction forces, Δf. The changes of the forces happen heterogeneously in space, indicating that collective non-affine motions of the disks are most pronounced when slip-avalanches occur. We analyze and predict the statistics for the force changes, Δf, by transition rates of the contact forces and angles, where slip-avalanches are characterized by wide power-law tails. We find that the transition rates are described by a q-Gaussian distribution regardless of the area fraction of the disks. Because the transition rates quantify structural changes of the force-chains, our findings are an important step towards linking macroscopic observations to a microscopic theory of slip-avalanches in the experimentally accessible quasi-static regime.
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Affiliation(s)
- Kuniyasu Saitoh
- Research Alliance Center for Mathematical Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
- WPI-Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Norihiro Oyama
- Mathematics for Advanced Materials-OIL, AIST, Sendai 980-8577, Japan
| | - Fumiko Ogushi
- Center for Materials Research by Information Integration, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
- Kyoto University Institute for Advanced Study, Kyoto University, Yoshida Ushinomiya-cho, Sakyo-ku, Kyoto, Japan
| | - Stefan Luding
- Faculty of Engineering Technology, MESA+, University of Twente, Drienerlolaan 5, Enschede, The Netherlands
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31
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Pan Y, Wu H, Wang X, Sun Q, Xiao L, Ding X, Sun J, Salje EKH. Rotatable precipitates change the scale-free to scale dependent statistics in compressed Ti nano-pillars. Sci Rep 2019; 9:3778. [PMID: 30846841 PMCID: PMC6405840 DOI: 10.1038/s41598-019-40526-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 02/14/2019] [Indexed: 11/09/2022] Open
Abstract
Compressed nano-pillars crackle from moving dislocations, which reduces plastic stability. Crackling noise is characterized by stress drops or strain bursts, which scale over a large region of sizes leading to power law statistics. Here we report that this “classic” behaviour is not valid in Ti-based nanopillars for a counterintuitive reason: we tailor precipitates inside the nano-pillar, which “regulate” the flux of dislocations. It is not because the nano-pillars become too small to sustain large dislocation movements, the effect is hence independent of size. Our precipitates act as “rotors”: local stress initiates the rotation of inclusions, which reduces the stress amplitudes dramatically. The size distribution of stress drops simultaneously changes from power law to exponential. Rotors act like revolving doors limiting the number of passing dislocations. Hence each collapse becomes weak. We present experimental evidence for Ti-based nano-pillars (diameters between 300 nm and 2 μm) with power law distributions of crackling noise P(s) ∼ s−τ with τ ∼ 2 in the defect free or non-rotatable precipitate states. Rotors change the size distribution to P(s) ∼ exp(−s/s0). Rotors are inclusions of ω-phase that aligns under stress along slip planes and limit dislocation glide to small distances with high nucleation rates. This opens new ways to make nano-pillars more stable.
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Affiliation(s)
- Yan Pan
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Haijun Wu
- Department of Materials Science and Engineering, National University of Singapore, Singapore, 117575, Singapore
| | - Xiaofei Wang
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Qiaoyan Sun
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Lin Xiao
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Xiangdong Ding
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China.
| | - Jun Sun
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Ekhard K H Salje
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China. .,Department of Earth Sciences, University of Cambridge, Cambridge, CB2 3EQ, United Kingdom.
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Salje EKH, Liu H, Xiao Y, Jin L, Planes A, Vives E, Xie K, Jiang X. Avalanche mixing and the simultaneous collapse of two media under uniaxial stress. Phys Rev E 2019; 99:023002. [PMID: 30934264 DOI: 10.1103/physreve.99.023002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Indexed: 06/09/2023]
Abstract
Avalanches in coal and sandstone samples under common uniaxial stress serve as a model for mixing of avalanche exponents in ceramics, multiferroics, and alloys. The two media are sandwiched together and subjected to common uniaxial stress using high- and low-stress compression. Each medium collapses individually through avalanches that often coincide with secondary avalanches into the other medium. The total avalanche time sequence allows a detailed investigation of the mixing by superposition and delayed coincidence. Correlations can be described by an inter-media Båth's law.
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Affiliation(s)
- Ekhard K H Salje
- School of Civil Engineering, Chongqing University, 400044 Chongqing, People's Republic of China
- State Key Laboratory for Mechanical Behaviors of Materials, Xi'an Jiao Tong University, 710049 Xi'an, People's Republic of China
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, United Kingdom
| | - Hanlong Liu
- School of Civil Engineering, Chongqing University, 400044 Chongqing, People's Republic of China
| | - Yang Xiao
- School of Civil Engineering, Chongqing University, 400044 Chongqing, People's Republic of China
| | - Linsen Jin
- School of Civil Engineering, Chongqing University, 400044 Chongqing, People's Republic of China
| | - Antoni Planes
- Departament de Física de la Matèria Condensada, Facultat de Física, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Catalonia
| | - Eduard Vives
- Departament de Física de la Matèria Condensada, Facultat de Física, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Catalonia
| | - Kainan Xie
- Departament de Física de la Matèria Condensada, Facultat de Física, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Catalonia
- State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, 400044 Chongqing, People's Republic of China
| | - Xiang Jiang
- School of Civil Engineering, Chongqing University, 400044 Chongqing, People's Republic of China
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, United Kingdom
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Chen S, Wang J, Xia L, Wu Y. Deformation Behavior of Bulk Metallic Glasses and High Entropy Alloys under Complex Stress Fields: A Review. ENTROPY 2019; 21:e21010054. [PMID: 33266770 PMCID: PMC7514161 DOI: 10.3390/e21010054] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 01/05/2019] [Accepted: 01/09/2019] [Indexed: 12/17/2022]
Abstract
The plastic deformation of bulk metallic glasses (BMGs) depends significantly on applied stress states, and more importantly, in practical applications of BMGs as structural materials, they always deform under complex stress fields. The understanding of deformation behavior of BMGs under complex stress fields is important not only for uncovering the plastic deformation mechanisms of BMGs, but also for developing BMG components with excellent mechanical performance. In this article, we briefly summarize the recent research progress on the deformation behavior of BMGs under complex stress fields, including the formation and propagation of shear bands, tunable macroscopic plasticity, and serrated plastic flows. The effect of complex stress fields on the plastic deformation mechanisms of BMGs is discussed from simple stress gradient to tailored complex stress fields. The deformation behavior of high entropy alloys (HEAs) under complex stress states has also been discussed. Challenges, potential implications and some unresolved issues are proposed.
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Affiliation(s)
- Shunhua Chen
- School of Mechanical Engineering, Hefei University of Technology, Hefei 230009, China
- National-Local Joint Engineering Research Centre of Nonferrous Metals and Processing Technology, Hefei 230009, China
- Correspondence: (S.C.); (Y.W.)
| | - Jingyuan Wang
- School of Mechanical Engineering, Hefei University of Technology, Hefei 230009, China
| | - Lei Xia
- Laboratory for Microstructures, Shanghai University, Shanghai 200444, China
| | - Yucheng Wu
- National-Local Joint Engineering Research Centre of Nonferrous Metals and Processing Technology, Hefei 230009, China
- School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, China
- Correspondence: (S.C.); (Y.W.)
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Herrero-Gómez C, Samwer K. Mechanical avalanches promoted by magnetoelastic coupling in magnetic metallic glasses. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:465803. [PMID: 30247152 DOI: 10.1088/1361-648x/aae3bc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The effect of magnetoelastic coupling on the mechanical behavior of magnetic metallic glasses is studied by superposing a magnetic field to the mechanical load during deformation experiments. The mechanical response is studied from the point of view of the global behavior, characterized by the Young's modulus, and from the perspective of the avalanches, estimated from the intermittency of the deformation signal. The influence of several intensities and orientations of magnetic field is analyzed in two amorphous alloys with different magnetostriction. For the highly magnetostrictive alloy, the decrease of the macroscopic Young's modulus under certain magnetic fields is accompanied by the promotion of mechanical avalanches, a fact that suggests that in this case the magnetoelastic coupling involves some extent of non-linear addition of the magnetic and mechanical energies.
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Affiliation(s)
- Carlos Herrero-Gómez
- I. Physikalisches Institut Georg-August-Universität Göttingen, Göttingen 37077, Germany
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35
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Tyukodi B, Vandembroucq D, Maloney CE. Diffusion in Mesoscopic Lattice Models of Amorphous Plasticity. PHYSICAL REVIEW LETTERS 2018; 121:145501. [PMID: 30339423 DOI: 10.1103/physrevlett.121.145501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 05/21/2018] [Indexed: 06/08/2023]
Abstract
We present results on tagged particle diffusion in a mesoscale lattice model for sheared amorphous material in athermal quasistatic conditions. We find a short time diffusive regime and a long time diffusive regime whose diffusion coefficients depend on system size in dramatically different ways. At short time, we find that the diffusion coefficient, D, scales roughly linearly with system length, D∼L^{1.05}. This short time behavior is consistent with particle-based simulations. The long-time diffusion coefficient scales like D∼L^{1.6}, close to previous studies which found D∼L^{1.5}. Furthermore, we show that the near-field details of the interaction kernel do not affect the short time behavior but qualitatively and dramatically affect the long time behavior, potentially causing a saturation of the mean-squared displacement at long times. Our finding of a D∼L^{1.05} short time scaling resolves a long standing puzzle about the disagreement between the diffusion coefficient measured in particle-based models and mesoscale lattice models of amorphous plasticity.
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Affiliation(s)
- Botond Tyukodi
- PMMH, ESPCI Paris, CNRS UMR 7636, Sorbonne Université, Université Paris Diderot, PSL Research University 10 rue Vauquelin, 75231 Paris cedex 05, France
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, Massachusetts 02115, USA
- Department of Physics, Babeş-Bolyai University, Cluj-Napoca 400084, Romania
| | - Damien Vandembroucq
- PMMH, ESPCI Paris, CNRS UMR 7636, Sorbonne Université, Université Paris Diderot, PSL Research University 10 rue Vauquelin, 75231 Paris cedex 05, France
| | - Craig E Maloney
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, Massachusetts 02115, USA
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36
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Alghamdi S, Du F, Yang J, Tan T. The role of water in the initial sliding of nacreous tablets: Findings from the torsional fracture of dry and hydrated nacre. J Mech Behav Biomed Mater 2018; 88:322-329. [PMID: 30196188 DOI: 10.1016/j.jmbbm.2018.08.051] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 08/27/2018] [Accepted: 08/30/2018] [Indexed: 01/25/2023]
Abstract
Nacre exhibits remarkable mechanical properties resulting from its hierarchical brick-and-mortar structures. By using pure shear stresses of torsion, we demonstrate how nacre resists the initial tablet sliding by tuning its nanoscale toughening mechanisms in dry and hydrated conditions. In hydrated nacre, hydrogen bonds between water molecules and organic matrices provide temporal paths for stress redistributions, through which the shear resistance is gradually transferred from mineral bridges to contacted nanoasperities. In the subsequent sliding, dynamical interactions between nacreous tablets enable substantial plasticity before the catastrophic failure of hydrated nacre. Our findings should help pursuing further insights into the interfacial behavior of natural and artificial laminated nanomaterials under different conditions.
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Affiliation(s)
- Saleh Alghamdi
- Department of Civil and Environmental Engineering, University of Vermont, 33 Colchester Avenue, Burlington, VT 05405, USA; Department of Civil Engineering, Taif University, Taif 21974, Saudi Arabia
| | - Fen Du
- Department of Mechanical Engineering, Vermont Technical College, Randolph Center, 201 Lawrence Pl, VT 05061, USA
| | - Jie Yang
- Department of Physics, University of Vermont, 82 University Place, Burlington, VT 05405, USA
| | - Ting Tan
- Department of Civil and Environmental Engineering, University of Vermont, 33 Colchester Avenue, Burlington, VT 05405, USA.
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37
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Poincloux S, Adda-Bedia M, Lechenault F. Crackling Dynamics in the Mechanical Response of Knitted Fabrics. PHYSICAL REVIEW LETTERS 2018; 121:058002. [PMID: 30118262 DOI: 10.1103/physrevlett.121.058002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 06/08/2018] [Indexed: 06/08/2023]
Abstract
Crackling noise, which occurs in a wide range of situations, is characterized by discrete events of various sizes, often correlated in the form of avalanches. We report experimental evidence that the mechanical response of a knitted fabric displays such broadly distributed events both in the force signal and in the deformation field, with statistics analogous to that of earthquakes or soft amorphous materials. A knit consists of a regular network of frictional contacts, linked by the elasticity of the yarn. When deformed, the fabric displays spatially extended avalanchelike yielding events resulting from collective interyarn contact slips. We measure the size distribution of these avalanches, at the stitch level from the analysis of nonelastic displacement fields and externally from force fluctuations. The two measurements yield consistent power law distributions reminiscent of those found in other avalanching systems. Our study shows that a knitted fabric is not only a thread-based metamaterial with highly sought after mechanical properties, but also an original, model system, with topologically protected structural order, where an intermittent, scale-invariant response emerges from minimal ingredients, and thus a significant landmark in the study of out-of-equilibrium universality.
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Affiliation(s)
- Samuel Poincloux
- Laboratoire de Physique Statistique, Ecole Normale Supérieure, PSL Research University, Sorbonne University, CNRS, F-75231 Paris, France
| | - Mokhtar Adda-Bedia
- Université de Lyon, Ecole Normale Supérieure de Lyon, Université Claude Bernard, CNRS, Laboratoire de Physique, F-69342 Lyon, France
| | - Frédéric Lechenault
- Laboratoire de Physique Statistique, Ecole Normale Supérieure, PSL Research University, Sorbonne University, CNRS, F-75231 Paris, France
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38
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McFaul LW, Wright WJ, Gu X, Uhl JT, Dahmen KA. Aftershocks in slowly compressed bulk metallic glasses: Experiments and theory. Phys Rev E 2018; 97:063005. [PMID: 30011456 DOI: 10.1103/physreve.97.063005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Indexed: 11/07/2022]
Abstract
We observe two distinct interevent time patterns in the slip avalanches of compressed bulk metallic glasses (BMGs). Small slip avalanches cluster together in time, but large slip avalanches recur roughly periodically. We compare the timing patterns of BMG slip avalanches with timing patterns of earthquakes and with the predictions of a mean-field model. The time clustering of small avalanches is similar to the known time clustering of earthquake foreshocks and aftershocks.
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Affiliation(s)
- Louis W McFaul
- Department of Physics and Institute of Condensed Matter Theory, University of Illinois at Urbana Champaign, 1110 West Green Street, Urbana, Illinois 61801, USA
| | - Wendelin J Wright
- Department of Mechanical Engineering, One Dent Drive, Bucknell University, Lewisburg, Pennsylvania 17837, USA.,Department of Chemical Engineering, One Dent Drive, Bucknell University, Lewisburg, Pennsylvania 17837, USA
| | - Xiaojun Gu
- Department of Mechanical Engineering, One Dent Drive, Bucknell University, Lewisburg, Pennsylvania 17837, USA
| | - Jonathan T Uhl
- Department of Physics and Institute of Condensed Matter Theory, University of Illinois at Urbana Champaign, 1110 West Green Street, Urbana, Illinois 61801, USA
| | - Karin A Dahmen
- Department of Physics and Institute of Condensed Matter Theory, University of Illinois at Urbana Champaign, 1110 West Green Street, Urbana, Illinois 61801, USA
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39
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Nicolas A, Rottler J. Orientation of plastic rearrangements in two-dimensional model glasses under shear. Phys Rev E 2018; 97:063002. [PMID: 30011591 DOI: 10.1103/physreve.97.063002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Indexed: 06/08/2023]
Abstract
The plastic deformation of amorphous solids is mediated by localized shear transformations involving small groups of particles rearranging irreversibly in an elastic background. We introduce and compare three different computational methods to extract the size and orientation of these shear transformations in simulations of a two-dimensional athermal model glass under simple shear. We find that the shear angles are broadly distributed around the macroscopic shear direction, with a more or less Gaussian distribution with a standard deviation of around 20^{∘}. The distributions of sizes and orientations of shear transformations display no substantial sensitivity to the shear rate. These results can notably be used to refine the description of rearrangements in elastoplastic models.
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Affiliation(s)
- Alexandre Nicolas
- LPTMS, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay, France
| | - Jörg Rottler
- Department of Physics and Astronomy and Quantum Matter Institute, University of British Columbia, Vancouver BC V6T 1Z1, Canada
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40
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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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41
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Coleman JP, Dahmen KA, Weaver RL. Avalanches and scaling collapse in the large-N Kuramoto model. Phys Rev E 2018; 97:042219. [PMID: 29758706 DOI: 10.1103/physreve.97.042219] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Indexed: 06/08/2023]
Abstract
We study avalanches in the Kuramoto model, defined as excursions of the order parameter due to ephemeral episodes of synchronization. We present scaling collapses of the avalanche sizes, durations, heights, and temporal profiles, extracting scaling exponents, exponent relations, and scaling functions that are shown to be consistent with the scaling behavior of the power spectrum, a quantity independent of our particular definition of an avalanche. A comprehensive scaling picture of the noise in the subcritical finite-N Kuramoto model is developed, linking this undriven system to a larger class of driven avalanching systems.
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Affiliation(s)
- J Patrick Coleman
- Department of Physics, University of Illinois, 1110 West Green Street, Urbana, Illinois 61801, USA
| | - Karin A Dahmen
- Department of Physics, University of Illinois, 1110 West Green Street, Urbana, Illinois 61801, USA
| | - Richard L Weaver
- Department of Physics, University of Illinois, 1110 West Green Street, Urbana, Illinois 61801, USA
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42
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Fan M, Zhang K, Schroers J, Shattuck MD, O'Hern CS. Particle rearrangement and softening contributions to the nonlinear mechanical response of glasses. Phys Rev E 2018; 96:032602. [PMID: 29346996 DOI: 10.1103/physreve.96.032602] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Indexed: 11/07/2022]
Abstract
Amorphous materials such as metallic, polymeric, and colloidal glasses exhibit complex preparation-dependent mechanical response to applied shear. In particular, glassy solids yield, with a mechanical response that transitions from elastic to plastic, with increasing shear strain. We perform numerical simulations to investigate the mechanical response of binary Lennard-Jones glasses undergoing athermal, quasistatic pure shear as a function of the cooling rate R used to prepare them. The ensemble-averaged stress versus strain curve 〈σ(γ)〉 resembles the spatial average in the large size limit, which appears smooth and displays a putative elastic regime at small strains, a yielding-related peak in stress at intermediate strain, and a plastic flow regime at large strains. In contrast, for each glass configuration in the ensemble, the stress-strain curve σ(γ) consists of many short nearly linear segments that are punctuated by particle-rearrangement-induced rapid stress drops. To explain the nonlinearity of 〈σ(γ)〉, we quantify the shape of the small stress-strain segments and the frequency and size of the stress drops in each glass configuration. We decompose the stress loss [i.e., the deviation in the slope of 〈σ(γ)〉 from that at 〈σ(0)〉] into the loss from particle rearrangements and the loss from softening [i.e., the reduction of the slopes of the linear segments in σ(γ)], and then compare the two contributions as a function of R and γ. For the current studies, the rearrangement-induced stress loss is larger than the softening-induced stress loss, however, softening stress losses increase with decreasing cooling rate. We also characterize the structure of the potential energy landscape along the strain direction for glasses prepared with different R, and observe a dramatic change of the properties of the landscape near the yielding transition. We then show that the rearrangement-induced energy loss per strain can serve as an order parameter for the yielding transition, which sharpens for slow cooling rates and in large systems.
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Affiliation(s)
- Meng Fan
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06520, USA.,Center for Research on Interface Structures and Phenomena, Yale University, New Haven, Connecticut 06520, USA
| | - Kai Zhang
- Department of Chemical Engineering, Columbia University, New York, New York 10027, USA
| | - Jan Schroers
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06520, USA.,Center for Research on Interface Structures and Phenomena, Yale University, New Haven, Connecticut 06520, USA
| | - Mark D Shattuck
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06520, USA.,Department of Physics and Benjamin Levich Institute, The City College of the City University of New York, New York, New York 10031, USA
| | - Corey S O'Hern
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06520, USA.,Center for Research on Interface Structures and Phenomena, Yale University, New Haven, Connecticut 06520, USA.,Department of Physics, Yale University, New Haven, Connecticut 06520, USA.,Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA
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43
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Understanding the mechanisms of amorphous creep through molecular simulation. Proc Natl Acad Sci U S A 2017; 114:13631-13636. [PMID: 29229846 DOI: 10.1073/pnas.1708618114] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Molecular processes of creep in metallic glass thin films are simulated at experimental timescales using a metadynamics-based atomistic method. Space-time evolutions of the atomic strains and nonaffine atom displacements are analyzed to reveal details of the atomic-level deformation and flow processes of amorphous creep in response to stress and thermal activations. From the simulation results, resolved spatially on the nanoscale and temporally over time increments of fractions of a second, we derive a mechanistic explanation of the well-known variation of creep rate with stress. We also construct a deformation map delineating the predominant regimes of diffusional creep at low stress and high temperature and deformational creep at high stress. Our findings validate the relevance of two original models of the mechanisms of amorphous plasticity: one focusing on atomic diffusion via free volume and the other focusing on stress-induced shear deformation. These processes are found to be nonlinearly coupled through dynamically heterogeneous fluctuations that characterize the slow dynamics of systems out of equilibrium.
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44
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Ding X, Aktas O, Wang X, Li S, Zhao Z, Zhang L, He X, Lookman T, Saxena A, Sun J. Statistics of twinning in strained ferroelastics. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:394002. [PMID: 28825916 DOI: 10.1088/1361-648x/aa7ea0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this review, we show that the evolution of the microstructure and kinetics of ferroelastic crystals under external shear can be explored by computer simulations of 2D model materials. We find that the nucleation and propagation of twin boundaries in ferroelastics depend sensitively on temperature. In the plastic regime, the evolution of the ferroelastic microstructure under strain deformation maintains a stick-and-slip mechanism in all temperature regimes, whereas the dynamic behavior changes dramatically from power-law statistics at low temperature to a Kohlrausch law at intermediate temperature, and then to a Vogel-Fulcher law at high temperature. In the yield regime, the distribution of jerk energies follows power-law statistics in all temperature regimes for a large range of strain rates. The non-spanning avalanches in the yield regime follow a parabolic temporal profile. The changes of twin pattern and twin boundaries density represent an important step towards domain boundary engineering.
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Affiliation(s)
- Xiangdong Ding
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiao Tong University, Xi'an 710049, People's Republic of China
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45
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Salje EKH, Planes A, Vives E. Analysis of crackling noise using the maximum-likelihood method: Power-law mixing and exponential damping. Phys Rev E 2017; 96:042122. [PMID: 29347614 DOI: 10.1103/physreve.96.042122] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Indexed: 06/07/2023]
Abstract
Crackling noise can be initiated by competing or coexisting mechanisms. These mechanisms can combine to generate an approximate scale invariant distribution that contains two or more contributions. The overall distribution function can be analyzed, to a good approximation, using maximum-likelihood methods and assuming that it follows a power law although with nonuniversal exponents depending on a varying lower cutoff. We propose that such distributions are rather common and originate from a simple superposition of crackling noise distributions or exponential damping.
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Affiliation(s)
- Ekhard K H Salje
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, United Kingdom
| | - Antoni Planes
- Departament de Física de la Matèria Condensada, Facultat de Física, Universitat de Barcelona, Martí i Franquès,1, E-08028 Barcelona, Catalonia
| | - Eduard Vives
- Departament de Física de la Matèria Condensada, Facultat de Física, Universitat de Barcelona, Martí i Franquès,1, E-08028 Barcelona, Catalonia
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46
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Abstract
Plastic yielding of amorphous solids occurs by power-law distributed deformation avalanches whose universality is still debated. Experiments and molecular dynamics simulations are hampered by limited statistical samples, and although existing stochastic models give precise exponents, they require strong assumptions about fixed deformation directions, at odds with the statistical isotropy of amorphous materials. Here, we introduce a fully tensorial, stochastic mesoscale model for amorphous plasticity that links the statistical physics of plastic yielding to engineering mechanics. It captures the complex shear patterning observed for a wide variety of deformation modes, as well as the avalanche dynamics of plastic flow. Avalanches are described by universal size exponents and scaling functions, avalanche shapes, and local stability distributions, independent of system dimensionality, boundary and loading conditions, and stress state. Our predictions consistently differ from those of mean-field depinning models, providing evidence that plastic yielding is a distinct type of critical phenomenon. The universality class for plastic yield in amorphous materials remains controversial. Here authors present a tensorial mesoscale model that captures both complex shear patterns and avalanche scaling behaviour, which differs from mean-field models and suggests a distinct type of critical phenomenon.
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47
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Sarkar R, Ebner C, Izadi E, Rentenberger C, Rajagopalan J. Revealing anelasticity and structural rearrangements in nanoscale metallic glass films using in situ TEM diffraction. MATERIALS RESEARCH LETTERS 2017; 5:135-143. [PMID: 28382229 PMCID: PMC5356196 DOI: 10.1080/21663831.2016.1228709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Accepted: 08/22/2016] [Indexed: 06/07/2023]
Abstract
We used a novel diffraction-based method to extract the local, atomic-level elastic strain in nanoscale amorphous TiAl films during in situ transmission electron microscopy deformation, while simultaneously measuring the macroscopic strain. The complementary strain measurements revealed significant anelastic deformation, which was independently confirmed by strain rate experiments. Furthermore, the distribution of first nearest-neighbor distances became narrower during loading and permanent changes were observed in the atomic structure upon unloading, even in the absence of macroscopic plasticity. The results demonstrate the capability of in situ electron diffraction to probe structural rearrangements and decouple elastic and anelastic deformation in metallic glasses.
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Affiliation(s)
- Rohit Sarkar
- Department of Materials Science and Engineering, School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, USA
| | - Christian Ebner
- Physics of Nanostructured Materials, Faculty of Physics, University of Vienna, Vienna, Austria
| | - Ehsan Izadi
- Department of Mechanical and Aerospace Engineering, School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, USA
| | - Christian Rentenberger
- Physics of Nanostructured Materials, Faculty of Physics, University of Vienna, Vienna, Austria
| | - Jagannathan Rajagopalan
- Department of Materials Science and Engineering, School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, USA
- Department of Mechanical and Aerospace Engineering, School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, USA
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48
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Zhang D, Dahmen KA, Ostoja-Starzewski M. Scaling of slip avalanches in sheared amorphous materials based on large-scale atomistic simulations. Phys Rev E 2017; 95:032902. [PMID: 28415186 DOI: 10.1103/physreve.95.032902] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Indexed: 11/07/2022]
Abstract
Atomistic simulations of binary amorphous systems with over 4 million atoms are performed. Systems of two interatomic potentials of the Lennard-Jones type, LJ12-6 and LJ9-6, are simulated. The athermal quasistatic shearing protocol is adopted, where the shear strain is applied in a stepwise fashion with each step followed by energy minimization. For each avalanche event, the shear stress drop (Δσ), the hydrostatic pressure drop (Δσ_{h}), and the potential energy drop (ΔE) are computed. It is found that, with the avalanche size increasing, the three become proportional to each other asymptotically. The probability distributions of avalanche sizes are obtained and values of scaling exponents fitted. In particular, the distributions follow a power law, P(ΔU)∼ΔU^{-τ}, where ΔU is a measure of avalanche sizes defined based on shear stress drops. The exponent τ is 1.25±0.1 for the LJ12-6 systems, and 1.15±0.1 for the LJ9-6 systems. The value of τ for the LJ12-6 systems is consistent with that from an earlier atomistic simulation study by Robbins et al. [Phys. Rev. Lett. 109, 105703 (2012)]PRLTAO0031-900710.1103/PhysRevLett.109.105703, but the fitted values of other scaling exponents differ, which may be because the shearing protocol used here differs from that in their study.
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Affiliation(s)
- Dansong Zhang
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Karin A Dahmen
- Department of Physics, Institute for Condensed Matter Theory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Martin Ostoja-Starzewski
- Department of Mechanical Science and Engineering, Institute for Condensed Matter Theory and Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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49
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Transition of Temporal Scaling Behavior in Percolation Assisted Shear-branching Structure during Plastic Deformation. Sci Rep 2017; 7:45083. [PMID: 28327562 PMCID: PMC5361155 DOI: 10.1038/srep45083] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 02/17/2017] [Indexed: 11/21/2022] Open
Abstract
This paper explores the temporal scaling behavior induced shear-branching structure in response to variant temperatures and strain rates during plastic deformation of Zr-based bulk metallic glass (BMG). The data analysis based on the compression tests suggests that there are two states of shear-branching structures: the fractal structure with a long-range order at an intermediate temperature of 223 K and a larger strain rate of 2.5 × 10−2 s−1; the disordered structure dominated at other temperature and strain rate. It can be deduced from the percolation theory that the compressive ductility, ec, can reach the maximum value at the intermediate temperature. Furthermore, a dynamical model involving temperature is given for depicting the shear-sliding process, reflecting the plastic deformation has fractal structure at the temperature of 223 K and strain rate of 2.5 × 10−2 s−1.
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50
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Denisov DV, Lőrincz KA, Wright WJ, Hufnagel TC, Nawano A, Gu X, Uhl JT, Dahmen KA, Schall P. Universal slip dynamics in metallic glasses and granular matter - linking frictional weakening with inertial effects. Sci Rep 2017; 7:43376. [PMID: 28262791 PMCID: PMC5338258 DOI: 10.1038/srep43376] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 01/23/2017] [Indexed: 11/09/2022] Open
Abstract
Slowly strained solids deform via intermittent slips that exhibit a material-independent critical size distribution. Here, by comparing two disparate systems - granular materials and bulk metallic glasses - we show evidence that not only the statistics of slips but also their dynamics are remarkably similar, i.e. independent of the microscopic details of the material. By resolving and comparing the full time evolution of avalanches in bulk metallic glasses and granular materials, we uncover a regime of universal deformation dynamics. We experimentally verify the predicted universal scaling functions for the dynamics of individual avalanches in both systems, and show that both the slip statistics and dynamics are independent of the scale and details of the material structure and interactions, thus settling a long-standing debate as to whether or not the claim of universality includes only the slip statistics or also the slip dynamics. The results imply that the frictional weakening in granular materials and the interplay of damping, weakening and inertial effects in bulk metallic glasses have strikingly similar effects on the slip dynamics. These results are important for transferring experimental results across scales and material structures in a single theory of deformation dynamics.
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Affiliation(s)
- Dmitry V Denisov
- Institute of Physics, University of Amsterdam, P.O. Box 94485, 1090 GL Amsterdam, The Netherlands
| | - Kinga A Lőrincz
- Institute of Physics, University of Amsterdam, P.O. Box 94485, 1090 GL Amsterdam, The Netherlands
| | - Wendelin J Wright
- Department of Mechanical Engineering, Bucknell University, One Dent Drive, Lewisburg, PA 17837.,Department of Chemical Engineering, Bucknell University, One Dent Drive, Lewisburg, PA 17837
| | - Todd C Hufnagel
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218.,Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218
| | - Aya Nawano
- Department of Physics, University of Illinois at Urbana Champaign, 1110 West Green Street, Urbana, IL 61801
| | - Xiaojun Gu
- Department of Mechanical Engineering, Bucknell University, One Dent Drive, Lewisburg, PA 17837
| | | | - Karin A Dahmen
- Department of Physics, University of Illinois at Urbana Champaign, 1110 West Green Street, Urbana, IL 61801
| | - Peter Schall
- Institute of Physics, University of Amsterdam, P.O. Box 94485, 1090 GL Amsterdam, The Netherlands
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