Length scale effects on the shear localization process in metallic glasses: A theoretical and computational study

Research output: Contribution to journalArticle

48 Citations (Scopus)

Abstract

Some recent experiments on sub-micron and nano-sized metallic glass (amorphous alloy) specimens have shown that the shear localization process becomes more stable and less catastrophic when compared to the response exhibited by large sample sizes. This leads to the discovery that the shear localization process and fracture can be delayed by decreasing sample volume. In this work we develop a non-local and finite-deformation-based constitutive model using thermodynamic principles and the theory of micro-force balance to study the causes for the aforementioned observations. The constitutive model has also been implemented into a commercially available finite-element program by writing a user-material subroutine. With the aid of finite-element simulations, our constitutive model predicts that metallic glass samples have the intrinsic ability to exhibit: (a) the delaying of (catastrophic) shear localization with decreasing sample size, and (b) homogeneous deformation behavior for sample volumes smaller than the shear band nucleus. The cause for the observations listed above is the increasing influence of a non-local interaction stress with decreasing sample volume. This interaction stress has energetic origins and it affects plastic deformation due to the strong coupling between plastic shearing and free-volume generation. Akin to strain-gradient plasticity theory, the role of the interaction stress is to strengthen the material at locations where the defect density/free volume is higher compared to the rest of metallic glass sample.

Original languageEnglish
Pages (from-to)1552-1575
Number of pages24
JournalJournal of the Mechanics and Physics of Solids
Volume59
Issue number8
DOIs
Publication statusPublished - Aug 2011
Externally publishedYes

Fingerprint

scale effect
Metallic glass
metallic glasses
Constitutive models
Free volume
shear
Shear bands
Defect density
Subroutines
Amorphous alloys
Shearing
Plasticity
Plastic deformation
Thermodynamics
Plastics
subroutines
causes
interactions
shearing
plastic properties

Keywords

  • Finite-element method
  • Metallic glass
  • Non-local constitutive theory
  • Strain localization
  • Viscoplasticity

ASJC Scopus subject areas

  • Mechanical Engineering
  • Mechanics of Materials
  • Condensed Matter Physics

Cite this

@article{e344617824fe4c74a6b52a4b326551d7,
title = "Length scale effects on the shear localization process in metallic glasses: A theoretical and computational study",
abstract = "Some recent experiments on sub-micron and nano-sized metallic glass (amorphous alloy) specimens have shown that the shear localization process becomes more stable and less catastrophic when compared to the response exhibited by large sample sizes. This leads to the discovery that the shear localization process and fracture can be delayed by decreasing sample volume. In this work we develop a non-local and finite-deformation-based constitutive model using thermodynamic principles and the theory of micro-force balance to study the causes for the aforementioned observations. The constitutive model has also been implemented into a commercially available finite-element program by writing a user-material subroutine. With the aid of finite-element simulations, our constitutive model predicts that metallic glass samples have the intrinsic ability to exhibit: (a) the delaying of (catastrophic) shear localization with decreasing sample size, and (b) homogeneous deformation behavior for sample volumes smaller than the shear band nucleus. The cause for the observations listed above is the increasing influence of a non-local interaction stress with decreasing sample volume. This interaction stress has energetic origins and it affects plastic deformation due to the strong coupling between plastic shearing and free-volume generation. Akin to strain-gradient plasticity theory, the role of the interaction stress is to strengthen the material at locations where the defect density/free volume is higher compared to the rest of metallic glass sample.",
keywords = "Finite-element method, Metallic glass, Non-local constitutive theory, Strain localization, Viscoplasticity",
author = "{G. Thamburaja}, {T Prakash}",
year = "2011",
month = "8",
doi = "10.1016/j.jmps.2011.04.018",
language = "English",
volume = "59",
pages = "1552--1575",
journal = "Journal of the Mechanics and Physics of Solids",
issn = "0022-5096",
publisher = "Elsevier Limited",
number = "8",

}

TY - JOUR

T1 - Length scale effects on the shear localization process in metallic glasses

T2 - A theoretical and computational study

AU - G. Thamburaja, T Prakash

PY - 2011/8

Y1 - 2011/8

N2 - Some recent experiments on sub-micron and nano-sized metallic glass (amorphous alloy) specimens have shown that the shear localization process becomes more stable and less catastrophic when compared to the response exhibited by large sample sizes. This leads to the discovery that the shear localization process and fracture can be delayed by decreasing sample volume. In this work we develop a non-local and finite-deformation-based constitutive model using thermodynamic principles and the theory of micro-force balance to study the causes for the aforementioned observations. The constitutive model has also been implemented into a commercially available finite-element program by writing a user-material subroutine. With the aid of finite-element simulations, our constitutive model predicts that metallic glass samples have the intrinsic ability to exhibit: (a) the delaying of (catastrophic) shear localization with decreasing sample size, and (b) homogeneous deformation behavior for sample volumes smaller than the shear band nucleus. The cause for the observations listed above is the increasing influence of a non-local interaction stress with decreasing sample volume. This interaction stress has energetic origins and it affects plastic deformation due to the strong coupling between plastic shearing and free-volume generation. Akin to strain-gradient plasticity theory, the role of the interaction stress is to strengthen the material at locations where the defect density/free volume is higher compared to the rest of metallic glass sample.

AB - Some recent experiments on sub-micron and nano-sized metallic glass (amorphous alloy) specimens have shown that the shear localization process becomes more stable and less catastrophic when compared to the response exhibited by large sample sizes. This leads to the discovery that the shear localization process and fracture can be delayed by decreasing sample volume. In this work we develop a non-local and finite-deformation-based constitutive model using thermodynamic principles and the theory of micro-force balance to study the causes for the aforementioned observations. The constitutive model has also been implemented into a commercially available finite-element program by writing a user-material subroutine. With the aid of finite-element simulations, our constitutive model predicts that metallic glass samples have the intrinsic ability to exhibit: (a) the delaying of (catastrophic) shear localization with decreasing sample size, and (b) homogeneous deformation behavior for sample volumes smaller than the shear band nucleus. The cause for the observations listed above is the increasing influence of a non-local interaction stress with decreasing sample volume. This interaction stress has energetic origins and it affects plastic deformation due to the strong coupling between plastic shearing and free-volume generation. Akin to strain-gradient plasticity theory, the role of the interaction stress is to strengthen the material at locations where the defect density/free volume is higher compared to the rest of metallic glass sample.

KW - Finite-element method

KW - Metallic glass

KW - Non-local constitutive theory

KW - Strain localization

KW - Viscoplasticity

UR - http://www.scopus.com/inward/record.url?scp=79957943032&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=79957943032&partnerID=8YFLogxK

U2 - 10.1016/j.jmps.2011.04.018

DO - 10.1016/j.jmps.2011.04.018

M3 - Article

AN - SCOPUS:79957943032

VL - 59

SP - 1552

EP - 1575

JO - Journal of the Mechanics and Physics of Solids

JF - Journal of the Mechanics and Physics of Solids

SN - 0022-5096

IS - 8

ER -