Shear Bands in Materials Processing: Understanding the Mechanics of Flow Localization From Zener's Time to the Present

Abstract Shear banding is a material instability in large strain plastic deformation of solids, where otherwise homogeneous flow becomes localized in narrow micrometer-scale bands. Shear bands have broad implications for materials processing and failure under dynamic loading in a wide variety of material systems ranging from metals to rocks. This year marks 75 years since the publication of Zener and Hollomon's pioneering work on shear bands (Zener and Hollomon, J Appl. Phys., 15, 22–32, 1944), which is widely credited with drawing the attention of the mechanics community to shear bands and related localization phenomena. Since this landmark publication, there has been significant experimental and theoretical investigation into the onset of shear banding. Yet, given the extremely small length and time scales associated with band development, several challenges persist in studying the evolution of single bands, postinitiation. For instance, spatiotemporal development of strain fields in the vicinity of a band, crucial to understanding the transition from localized flow to fracture, has remained largely unexplored. Recent full-field displacement measurements, coupled with numerical modeling, have only begun to ameliorate this problem. This article summarizes our present understanding of plastic flow dynamics around single shear bands and the subsequent transition to fracture, with special emphasis on the postinstability stage. These topics are covered specifically from a materials processing perspective. We begin with a semihistorical look at some of Zener's early ideas on shear bands and discuss recent advances in experimental methods for mapping localized flow during band formation, including direct in situ imaging as well as ex situ/postmortem analyses. Classical theories and analytical frameworks are revisited in the light of recently published experimental data. We show that shear bands exhibit a wealth of complex flow characteristics that bear striking resemblance to viscous fluid flows and related boundary layer phenomena. Finally, new material systems and strategies for reproducing shear band formation at low speeds are discussed. It is hoped that these will help further our understanding of shear band dynamics, the subsequent transition to fracture, and lead to practical “control” strategies for suppressing shear band-driven failures in processing applications.

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The influence of material non-uniformity preceding shear-band formation in a model for granular flow

European Journal of Applied Mathematics ◽

10.1017/s0956792597003070 ◽

1997 ◽

Vol 8 (5) ◽

pp. 457-483 ◽

Cited By ~ 3

Author(s):

DAVID G. SCHAEFFER ◽

MICHAEL SHEARER

Keyword(s):

Shear Band ◽

Material Properties ◽

Shear Banding ◽

Shear Bands ◽

Small Variation ◽

Band Formation ◽

Time Period ◽

Single Location ◽

Change Of Type ◽

Short Time

The onset of shear-banding in a deforming elastoplastic solid has been linked to change of type of the governing partial differential equations. If uniform material properties are assumed, then (i) deformations prior to shear-banding are uniform, and (ii) the onset of shear-banding occurs simultaneously at all points in the sample. In this paper we study, in the context of a model for anti-plane shearing of a granular material, the effect of a small variation in material properties (e.g. in yield strength) within the sample. Using matched asymptotic expansions, we find that (i) the deformation is extremely non-uniform in a short time period immediately preceding the formation of shear-bands; and (ii) generically, a shear-band forms at a single location in the sample.

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Nucleation and Boundary Layer Growth of Shear Bands in Machining

Journal of Manufacturing Science and Engineering ◽

10.1115/1.4044103 ◽

2019 ◽

Vol 141 (10) ◽

Cited By ~ 1

Author(s):

Shwetabh Yadav ◽

Dinakar Sagapuram

Keyword(s):

Boundary Layer ◽

Shear Band ◽

Shear Banding ◽

Shear Bands ◽

Critical Shear Stress ◽

Correlation Method ◽

Layer Growth ◽

Image Correlation ◽

Band Formation ◽

Stress Criterion

We demonstrate a novel approach to study shear banding in machining at low speeds using a low melting point alloy. In situ imaging and an image correlation method, particle image velocimetry (PIV), are used to capture shear band nucleation and quantitatively analyze the temporal evolution of the localized plastic flow around a shear band. The observations show that the shear band onset is governed by a critical shear stress criterion, while the displacement field around a freshly nucleated shear band evolves in a manner resembling the classical boundary layer formation in viscous fluids. The relevant shear band parameters, the stress at band formation, and local shear band viscosity are presented.

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Analysis of serrations and shear bands fractality in UFGs

Journal of the Mechanical Behavior of Materials ◽

10.1515/jmbm-2015-0001 ◽

2015 ◽

Vol 24 (1-2) ◽

pp. 1-9 ◽

Cited By ~ 9

Author(s):

Aggelos C. Iliopoulos ◽

Nikolaos S. Nikolaidis ◽

Elias C. Aifantis

Keyword(s):

Shear Band ◽

Shear Banding ◽

Shear Bands ◽

Ultrafine Grain ◽

Strain Rates ◽

Stress Strain ◽

Band Formation ◽

Serrated Flow ◽

Multiple Shear Band ◽

First Case

AbstractTsallis nonextensive statistics is employed to characterize serrated flow, as well as multiple shear band formation in ultrafine grain (UFG) size materials. Two such UFG materials, a bi-modal Al-Mg alloy and a Fe-Cu alloy, were chosen. In the first case, at low strain rates serrated flow emerges as recorded in the stress-strain graphs, whereas at high strain rates, extensive shear banding occurs. In the second case, multiple shear banding is the only mechanism for plastic deformation, but serrations in the stress-strain graph are not recorded. The analysis aims at the estimation of Tsallis entropic index qstat (stat denotes stationary state), as well as the estimation of fractal dimension. The results reveal that the distributions of serrations and shear bands do not follow Gaussian statistics as implied by Boltzmann-Gibbs extensive thermodynamics, but are approximated instead by Tsallis q-Gaussian distributions, as suggested by nonextensive thermodynamics. In addition, fractal analysis of multiple shear band images reveals a (multi)fractal and hierarchical profile of the spatial arrangement of shear bands.

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Experimental and Numerical Study of Intense Shear Banding for Al-Alloy under Uniaxial Tension

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.6-8.737 ◽

2005 ◽

Vol 6-8 ◽

pp. 737-744 ◽

Cited By ~ 3

Author(s):

Xin Jian Duan ◽

Mukesh K. Jain ◽

M. Bruhis ◽

David S. Wilkinson

Keyword(s):

Shear Band ◽

Uniaxial Tension ◽

Numerical Study ◽

Shear Banding ◽

Gauge Length ◽

Image Correlation ◽

Al Alloy ◽

Band Formation ◽

Full Field ◽

Intense Shear

The occurrence of intense shear band is a prelude to failure in many Al-sheet materials. In the present study, a full field optical system measurement technique (digital image correlation) and the finite element method are used to characterize the sequence of deformation in uniaxial tension before and after the intense shear band formation in AA6111-T4. The results indicate good agreement between the measurement and the predictions in terms of shear band width, strain distribution along the gauge length and the failure mode.

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δ’ (Al3Li) dissolution as a thermal probe in shear-banding studies

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100151726 ◽

1993 ◽

Vol 51 ◽

pp. 1178-1179

Author(s):

Roa Wen Chen ◽

Kenneth S. Vecchio

Keyword(s):

Shear Band ◽

Thermal History ◽

Shear Banding ◽

Shear Bands ◽

Dissolution Kinetics ◽

Alloy System ◽

Thermal Probe ◽

Band Formation ◽

Thermal Dissolution ◽

History Of

The Al-Li alloy system can provide a unique opportunity to study the thermal history of shear-band formation by following the thermal dissolution of the precipitate phase δ’ (Al3Li) as a function of Li concentration and δ’ solvus temperature. The Al-Li system was chosen primarily for the rather rapid precipitation and dissolution kinetics resulting from the high diffusivity of Li in the Al lattice. δ’ is a spherical, coherent and metastable precipitate which is the main strengthening phase in dilute Al-Li alloys. Although δ’ is metastable, the location of the δ’ solvus in the Al-Li phase diagram has been well documented for dilute Li additions (<5 wt.% Li).e.g.1 The metastable δ’ solvus increases in temperature with increasing Li concentration. As such, the dissolution of δ’ within the shear bands, as a function of Li alloy concentration, can provide an internal temperature probe to study the thermal history of the shear band.

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Identifying structural signatures of shear banding in model polymer nanopillars

Soft Matter ◽

10.1039/c8sm02423e ◽

2019 ◽

Vol 15 (22) ◽

pp. 4548-4561 ◽

Cited By ~ 9

Author(s):

Robert J. S. Ivancic ◽

Robert A. Riggleman

Keyword(s):

Machine Learning ◽

Shear Band ◽

Defect Structure ◽

Amorphous Materials ◽

Shear Banding ◽

Shear Band Formation ◽

Learning Methods ◽

Band Formation ◽

Mesoscale Models ◽

Machine Learning Methods

Shear band formation often proceeds fracture in amorphous materials. While mesoscale models postulate an underlying defect structure to explain this phenomenon, they do not detail the microscopic properties of these defects especially in strongly confined materials. Here, we use machine learning methods to uncover these microscopic defects in simulated polymer nanopillars.

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The Effect of Cold Rolling Reduction on Shear Band and Texture Formation in Fe-3%Si Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.715-716.158 ◽

2012 ◽

Vol 715-716 ◽

pp. 158-163 ◽

Cited By ~ 7

Author(s):

Kenichi Murakami ◽

N. Morishige ◽

Kohsaku Ushioda

Keyword(s):

Shear Band ◽

Cold Rolling ◽

Crystal Orientation ◽

Shear Bands ◽

Rolling Direction ◽

Orientation Distribution ◽

Rolling Reduction ◽

Shear Band Formation ◽

Band Formation ◽

Cold Rolling Reduction

The effect of cold rolling reduction on shear band formation and crystal orientation within shear bands and annealing texture were investigated in Fe-3%Si {111}<112> single crystals. Several types of shear bands were observed with different angles to rolling direction, dependent on rolling reduction. As for shear band formation, those with smaller angles were formed earlier and those with larger angles were formed later. Regarding crystal orientation along shear bands after rolling reduction, orientation distribution from the initial became large in accordance with reduction and even exceeded Goss orientation when rolling reduction became larger than 40%. After annealing, however, recrystallized grains along shear bands were mainly Goss grains regardless of reduction. The speculated reason for the dominance of Goss after annealing is that Goss subgrains with less density of dislocations were surrounded by largely deformed areas.

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Experimental Study on the Shear Band of Methane Hydrate-Bearing Sediment

Journal of Marine Science and Engineering ◽

10.3390/jmse9111158 ◽

2021 ◽

Vol 9 (11) ◽

pp. 1158

Author(s):

Xiaobing Lu ◽

Xuhui Zhang ◽

Fangfang Sun ◽

Shuyun Wang ◽

Lele Liu ◽

...

Keyword(s):

Shear Band ◽

Gas Hydrate ◽

Methane Hydrate ◽

Triaxial Compression ◽

Shear Banding ◽

Oblique Line ◽

Shear Bands ◽

Compression Tests ◽

Computer Tomography Scan ◽

Hydrate Saturation

The occurrence of a shear band is often thought as the precursor of failure. To study the initiation of shear banding in gas hydrate-bearing sediments, two groups of triaxial compression tests combined with a CT (computer tomography) scan were conducted by triaxial CT-integrated equipment under two confining pressures and seven hydrate saturations. The macro stress–strain curves and the corresponding CT scanning images of the micro-structure and the distribution of the components were obtained. The geometric parameters of the shear bands were measured based on the CT images at four typical axial strains, respectively. The distribution characteristics of soil particles, water, hydrate and gas were also analyzed. It is shown that the existence of methane hydrate changes the mechanical property of hydrate-bearing sediment from plastic failure to brittle failure when the hydrate saturation is over 13%, which occurs in the range of the tests in this paper. The peak of the deviatoric stress increases with the hydrate saturation. The shear band is in either a single oblique line or inter-cross lines depending on the hydrate saturation, the effective confining pressure and the initial distribution of the gas hydrate. Most of the shear band surfaces are not straight, and the widths of the shear bands are almost non-uniformly distributed.

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Shear Band Feature in Two Bulk Metallic Glasses with Different Inherent Plasticity

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.703.20 ◽

2013 ◽

Vol 703 ◽

pp. 20-23

Author(s):

Jian Sheng Gu ◽

Hui Feng Bo ◽

Hong Li ◽

Zhan Xin Zhang

Keyword(s):

Plastic Deformation ◽

Shear Band ◽

Temperature Rise ◽

Metallic Glasses ◽

Shear Banding ◽

Shear Bands ◽

Significant Difference ◽

Coating Method ◽

Deformation Ability

Shear banding characterization of Zr64.13Cu15.75Ni10.12Al10 and Zr65Cu15Ni10Al10 BMGs was studied by using Rockwell indention method. The significant difference in plastic deformation ability can be ascribed to different shear banding features. Meanwhile, by using the fusible coating method, thermal effect on shear bands was investigated. We did not see apparently temperature rise in shear bands of these two BMGs through Rockwell indentation.

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