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Title: Probing the limits of metal plasticity with molecular dynamics simulations

Abstract

Ordinarily, the strength and plasticity properties of a metal are defined by dislocations—line defects in the crystal lattice whose motion results in material slippage along lattice planes. Dislocation dynamics models are usually used as mesoscale proxies for true atomistic dynamics, which are computationally expensive to perform routinely. However, atomistic simulations accurately capture every possible mechanism of material response, resolving every “jiggle and wiggle” of atomic motion, whereas dislocation dynamics models do not. We present fully dynamic atomistic simulations of bulk single-crystal plasticity in the body-centred-cubic metal tantalum. Our goal is to quantify the conditions under which the limits of dislocation-mediated plasticity are reached and to understand what happens to the metal beyond any such limit. In our simulations, the metal is compressed at ultrahigh strain rates along its [001] crystal axis under conditions of constant pressure, temperature and strain rate. To address the complexity of crystal plasticity processes on the length scales (85–340 nm) and timescales (1 ns–1μs) that we examine, we use recently developed methods of in situ computational microscopy to recast the enormous amount of transient trajectory data generated in our simulations into a form that can be analysed by a human. Our simulations predict that, on reachingmore » certain limiting conditions of strain, dislocations alone can no longer relieve mechanical loads; instead, another mechanism, known as deformation twinning (the sudden re-orientation of the crystal lattice), takes over as the dominant mode of dynamic response. Below this limit, the metal assumes a strain-path-independent steady state of plastic flow in which the flow stress and the dislocation density remain constant as long as the conditions of straining thereafter remain unchanged. In this distinct state, tantalum flows like a viscous fluid while retaining its crystal lattice and remaining a strong and stiff metal.« less

Authors:
 [1];  [2];  [1];  [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Technical Univ. of Darmstadt (Germany)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA); Julich Research Center (Germany). Julich Supercomputing Center (JSC)
OSTI Identifier:
1459144
Report Number(s):
LLNL-JRNL-745692
Journal ID: ISSN 0028-0836; 930264
Grant/Contract Number:  
AC52-07NA27344; W-7405-Eng-48
Resource Type:
Accepted Manuscript
Journal Name:
Nature (London)
Additional Journal Information:
Journal Name: Nature (London); Journal Volume: 550; Journal Issue: 7677; Journal ID: ISSN 0028-0836
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 74 ATOMIC AND MOLECULAR PHYSICS; atomistic models; computational methods; mechanical properties; metals and alloys; structure of solids and liquids

Citation Formats

Zepeda-Ruiz, Luis A., Stukowski, Alexander, Oppelstrup, Tomas, and Bulatov, Vasily V. Probing the limits of metal plasticity with molecular dynamics simulations. United States: N. p., 2017. Web. doi:10.1038/nature23472.
Zepeda-Ruiz, Luis A., Stukowski, Alexander, Oppelstrup, Tomas, & Bulatov, Vasily V. Probing the limits of metal plasticity with molecular dynamics simulations. United States. doi:10.1038/nature23472.
Zepeda-Ruiz, Luis A., Stukowski, Alexander, Oppelstrup, Tomas, and Bulatov, Vasily V. Wed . "Probing the limits of metal plasticity with molecular dynamics simulations". United States. doi:10.1038/nature23472. https://www.osti.gov/servlets/purl/1459144.
@article{osti_1459144,
title = {Probing the limits of metal plasticity with molecular dynamics simulations},
author = {Zepeda-Ruiz, Luis A. and Stukowski, Alexander and Oppelstrup, Tomas and Bulatov, Vasily V.},
abstractNote = {Ordinarily, the strength and plasticity properties of a metal are defined by dislocations—line defects in the crystal lattice whose motion results in material slippage along lattice planes. Dislocation dynamics models are usually used as mesoscale proxies for true atomistic dynamics, which are computationally expensive to perform routinely. However, atomistic simulations accurately capture every possible mechanism of material response, resolving every “jiggle and wiggle” of atomic motion, whereas dislocation dynamics models do not. We present fully dynamic atomistic simulations of bulk single-crystal plasticity in the body-centred-cubic metal tantalum. Our goal is to quantify the conditions under which the limits of dislocation-mediated plasticity are reached and to understand what happens to the metal beyond any such limit. In our simulations, the metal is compressed at ultrahigh strain rates along its [001] crystal axis under conditions of constant pressure, temperature and strain rate. To address the complexity of crystal plasticity processes on the length scales (85–340 nm) and timescales (1 ns–1μs) that we examine, we use recently developed methods of in situ computational microscopy to recast the enormous amount of transient trajectory data generated in our simulations into a form that can be analysed by a human. Our simulations predict that, on reaching certain limiting conditions of strain, dislocations alone can no longer relieve mechanical loads; instead, another mechanism, known as deformation twinning (the sudden re-orientation of the crystal lattice), takes over as the dominant mode of dynamic response. Below this limit, the metal assumes a strain-path-independent steady state of plastic flow in which the flow stress and the dislocation density remain constant as long as the conditions of straining thereafter remain unchanged. In this distinct state, tantalum flows like a viscous fluid while retaining its crystal lattice and remaining a strong and stiff metal.},
doi = {10.1038/nature23472},
journal = {Nature (London)},
number = 7677,
volume = 550,
place = {United States},
year = {2017},
month = {9}
}

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Works referenced in this record:

Embedded-atom-method tantalum potential developed by the force-matching method
journal, March 2003


Dislocation multi-junctions and strain hardening
journal, April 2006

  • Bulatov, Vasily V.; Hsiung, Luke L.; Tang, Meijie
  • Nature, Vol. 440, Issue 7088
  • DOI: 10.1038/nature04658

Improbability of Void Growth in Aluminum via Dislocation Nucleation under Typical Laboratory Conditions
journal, January 2012


The temperature and strain rate dependence of the flow stress of tantalum
journal, August 1977

  • Hoge, K. G.; Mukherjee, A. K.
  • Journal of Materials Science, Vol. 12, Issue 8
  • DOI: 10.1007/BF00542818

Molecular dynamics simulations of shock-induced plasticity in tantalum
journal, March 2014


Microstructure of high-strain, high-strain-rate deformed tantalum
journal, February 1998


Barreling of Solid Cylinders Under Axial Compression
journal, April 1985

  • Banerjee, J. K.
  • Journal of Engineering Materials and Technology, Vol. 107, Issue 2
  • DOI: 10.1115/1.3225789

Unified physics of stretched exponential relaxation and Weibull fracture statistics
journal, December 2012

  • Mauro, John C.; Smedskjaer, Morten M.
  • Physica A: Statistical Mechanics and its Applications, Vol. 391, Issue 23
  • DOI: 10.1016/j.physa.2012.07.013

Evidence of enhanced self-organization in the work-hardening stage V of fcc metals
journal, March 2001


Fast Parallel Algorithms for Short-Range Molecular Dynamics
journal, March 1995


Effect of strain rate and dislocation density on the twinning behavior in tantalum
journal, April 2016

  • Florando, Jeffrey N.; El-Dasher, Bassem S.; Chen, Changqiang
  • AIP Advances, Vol. 6, Issue 4
  • DOI: 10.1063/1.4948528

Three-stage hardening in tantalum single crystals
journal, November 1965


Sur le durcissement dû à la recombinaison des dislocations
journal, December 1960


Phase Transformation in Tantalum under Extreme Laser Deformation
journal, October 2015

  • Lu, C. -H.; Hahn, E. N.; Remington, B. A.
  • Scientific Reports, Vol. 5, Issue 1
  • DOI: 10.1038/srep15064

Visualization and analysis of atomistic simulation data with OVITO–the Open Visualization Tool
journal, December 2009


Deformation twinning
journal, January 1995


Deformation of high purity tantalum single crystals at 4.2 K
journal, January 1975


Dislocation Velocities, Dislocation Densities, and Plastic Flow in Lithium Fluoride Crystals
journal, February 1959

  • Johnston, W. G.; Gilman, J. J.
  • Journal of Applied Physics, Vol. 30, Issue 2
  • DOI: 10.1063/1.1735121

Constrained deformation of molybdenum single crystals
journal, December 1975


Maximum entropy production principle in physics, chemistry and biology
journal, April 2006


Multiplication Processes for Slow Moving Dislocations
journal, August 1950


Fractal Dislocation Patterning During Plastic Deformation
journal, September 1998


Shock-induced phase transformation in tantalum
journal, September 2010


½<111> screw dislocations and the nucleation of {112}<111> twins in the b.c.c. lattice
journal, September 1963


Kinetics of flow and strain-hardening
journal, November 1981


A unified approach for extracting strength information from nonsimple compression waves. Part II. Experiment and comparison with simulation
journal, December 2011

  • Reed, Bryan W.; Reed Patterson, J.; Swift, Damian C.
  • Journal of Applied Physics, Vol. 110, Issue 11
  • DOI: 10.1063/1.3662173

Dynamic transitions from smooth to rough to twinning in dislocation motion
journal, February 2004

  • Marian, Jaime; Cai, Wei; Bulatov, Vasily V.
  • Nature Materials, Vol. 3, Issue 3
  • DOI: 10.1038/nmat1072

Parametric dislocation dynamics: A thermodynamics-based approach to investigations of mesoscopic plastic deformation
journal, January 2000


Does dislocation density have a natural limit?
journal, January 1977


Extracting dislocations and non-dislocation crystal defects from atomistic simulation data
journal, September 2010

  • Stukowski, Alexander; Albe, Karsten
  • Modelling and Simulation in Materials Science and Engineering, Vol. 18, Issue 8
  • DOI: 10.1088/0965-0393/18/8/085001

The onset of twinning in metals: a constitutive description
journal, November 2001


    Works referencing / citing this record:

    Structural Transformations in the Grain Boundary Region of Nanocrystalline Metals Under Mechanical Loading
    journal, December 2019

    • Zolnikov, K. P.; Kryzhevich, D. S.; Korchuganov, A. V.
    • Russian Physics Journal, Vol. 62, Issue 8
    • DOI: 10.1007/s11182-019-01855-0

    Century-long Taylor-Quinney interpretation of plasticity-induced heating reexamined
    journal, June 2019


    Structural Transformations in the Grain Boundary Region of Nanocrystalline Metals Under Mechanical Loading
    journal, December 2019

    • Zolnikov, K. P.; Kryzhevich, D. S.; Korchuganov, A. V.
    • Russian Physics Journal, Vol. 62, Issue 8
    • DOI: 10.1007/s11182-019-01855-0

    Century-long Taylor-Quinney interpretation of plasticity-induced heating reexamined
    journal, June 2019