---
_id: '9673'
abstract:
- lang: eng
  text: Current strategies of computational crystal plasticity that focus on individual
    atoms or dislocations are impractical for real-scale, large-strain problems even
    with today’s computing power. Dislocation-density based approaches are a way forward
    but a critical issue to address is a realistic description of the interactions
    between dislocations. In this paper, a new scheme for computational dynamics of
    dislocation-density functions is proposed, which takes full consideration of the
    mutual elastic interactions between dislocations based on the Hirth–Lothe formulation.
    Other features considered include (i) the continuity nature of the movements of
    dislocation densities, (ii) forest hardening, (iii) generation according to high
    spatial gradients in dislocation densities, and (iv) annihilation. Numerical implementation
    by the finite-volume method, which is well suited for flow problems with high
    gradients, is discussed. Numerical examples performed for a single-crystal aluminum
    model show typical strength anisotropy behavior comparable to experimental observations.
    Furthermore, a detailed case study on small-scale crystal plasticity successfully
    captures a number of key experimental features, including power-law relation between
    strength and size, low dislocation storage and jerky deformation.
article_processing_charge: No
article_type: original
author:
- first_name: H.S.
  full_name: Leung, H.S.
  last_name: Leung
- first_name: P.S.S.
  full_name: Leung, P.S.S.
  last_name: Leung
- first_name: Bingqing
  full_name: Cheng, Bingqing
  id: cbe3cda4-d82c-11eb-8dc7-8ff94289fcc9
  last_name: Cheng
  orcid: 0000-0002-3584-9632
- first_name: A.H.W.
  full_name: Ngan, A.H.W.
  last_name: Ngan
citation:
  ama: Leung HS, Leung PSS, Cheng B, Ngan AHW. A new dislocation-density-function
    dynamics scheme for computational crystal plasticity by explicit consideration
    of dislocation elastic interactions. <i>International Journal of Plasticity</i>.
    2015;67:1-25. doi:<a href="https://doi.org/10.1016/j.ijplas.2014.09.009">10.1016/j.ijplas.2014.09.009</a>
  apa: Leung, H. S., Leung, P. S. S., Cheng, B., &#38; Ngan, A. H. W. (2015). A new
    dislocation-density-function dynamics scheme for computational crystal plasticity
    by explicit consideration of dislocation elastic interactions. <i>International
    Journal of Plasticity</i>. Elsevier. <a href="https://doi.org/10.1016/j.ijplas.2014.09.009">https://doi.org/10.1016/j.ijplas.2014.09.009</a>
  chicago: Leung, H.S., P.S.S. Leung, Bingqing Cheng, and A.H.W. Ngan. “A New Dislocation-Density-Function
    Dynamics Scheme for Computational Crystal Plasticity by Explicit Consideration
    of Dislocation Elastic Interactions.” <i>International Journal of Plasticity</i>.
    Elsevier, 2015. <a href="https://doi.org/10.1016/j.ijplas.2014.09.009">https://doi.org/10.1016/j.ijplas.2014.09.009</a>.
  ieee: H. S. Leung, P. S. S. Leung, B. Cheng, and A. H. W. Ngan, “A new dislocation-density-function
    dynamics scheme for computational crystal plasticity by explicit consideration
    of dislocation elastic interactions,” <i>International Journal of Plasticity</i>,
    vol. 67. Elsevier, pp. 1–25, 2015.
  ista: Leung HS, Leung PSS, Cheng B, Ngan AHW. 2015. A new dislocation-density-function
    dynamics scheme for computational crystal plasticity by explicit consideration
    of dislocation elastic interactions. International Journal of Plasticity. 67,
    1–25.
  mla: Leung, H. S., et al. “A New Dislocation-Density-Function Dynamics Scheme for
    Computational Crystal Plasticity by Explicit Consideration of Dislocation Elastic
    Interactions.” <i>International Journal of Plasticity</i>, vol. 67, Elsevier,
    2015, pp. 1–25, doi:<a href="https://doi.org/10.1016/j.ijplas.2014.09.009">10.1016/j.ijplas.2014.09.009</a>.
  short: H.S. Leung, P.S.S. Leung, B. Cheng, A.H.W. Ngan, International Journal of
    Plasticity 67 (2015) 1–25.
date_created: 2021-07-15T14:09:32Z
date_published: 2015-04-01T00:00:00Z
date_updated: 2023-02-23T14:04:28Z
day: '01'
doi: 10.1016/j.ijplas.2014.09.009
extern: '1'
intvolume: '        67'
language:
- iso: eng
month: '04'
oa_version: None
page: 1-25
publication: International Journal of Plasticity
publication_identifier:
  issn:
  - 0749-6419
publication_status: published
publisher: Elsevier
scopus_import: '1'
status: public
title: A new dislocation-density-function dynamics scheme for computational crystal
  plasticity by explicit consideration of dislocation elastic interactions
type: journal_article
user_id: 6785fbc1-c503-11eb-8a32-93094b40e1cf
volume: 67
year: '2015'
...
---
_id: '9674'
abstract:
- lang: eng
  text: The coalescence of nano-crystals during sintering is often found to result
    in interesting crystalline structures such as multi-fold twins, and yet the plasticity
    mechanism accompanying their formation is unclear. In this work, the sintering
    behavior of two unsupported copper nanoparticles initially at room temperature
    is investigated by molecular dynamics simulations under the constant-energy ensemble.
    The results reveal that once the two nanoparticles are brought into contact, they
    often go through drastic structural changes with the inter-particle grain boundary
    quickly eliminated, and single- and multi-fold twinning occurs frequently in the
    coalesced product. Whereas the formation of single twins is found to be via the
    more usual mechanism of emission of Shockley partials on {1 1 1} planes, the formation
    of fivefold twins, however, takes place via a novel dislocation-free mechanism
    involving a series of shear and rigid-body rotation processes caused by elastic
    waves with amplitudes not corresponding to any allowable Burgers vector in the
    fcc lattice. Such a lattice-wave, dislocation-free twinning mechanism has never
    been reported before.
article_processing_charge: No
article_type: original
author:
- first_name: Bingqing
  full_name: Cheng, Bingqing
  id: cbe3cda4-d82c-11eb-8dc7-8ff94289fcc9
  last_name: Cheng
  orcid: 0000-0002-3584-9632
- first_name: Alfonso H.W.
  full_name: Ngan, Alfonso H.W.
  last_name: Ngan
citation:
  ama: 'Cheng B, Ngan AHW. The crystal structures of sintered copper nanoparticles:
    A molecular dynamics study. <i>International Journal of Plasticity</i>. 2013;47:65-79.
    doi:<a href="https://doi.org/10.1016/j.ijplas.2013.01.006">10.1016/j.ijplas.2013.01.006</a>'
  apa: 'Cheng, B., &#38; Ngan, A. H. W. (2013). The crystal structures of sintered
    copper nanoparticles: A molecular dynamics study. <i>International Journal of
    Plasticity</i>. Elsevier. <a href="https://doi.org/10.1016/j.ijplas.2013.01.006">https://doi.org/10.1016/j.ijplas.2013.01.006</a>'
  chicago: 'Cheng, Bingqing, and Alfonso H.W. Ngan. “The Crystal Structures of Sintered
    Copper Nanoparticles: A Molecular Dynamics Study.” <i>International Journal of
    Plasticity</i>. Elsevier, 2013. <a href="https://doi.org/10.1016/j.ijplas.2013.01.006">https://doi.org/10.1016/j.ijplas.2013.01.006</a>.'
  ieee: 'B. Cheng and A. H. W. Ngan, “The crystal structures of sintered copper nanoparticles:
    A molecular dynamics study,” <i>International Journal of Plasticity</i>, vol.
    47. Elsevier, pp. 65–79, 2013.'
  ista: 'Cheng B, Ngan AHW. 2013. The crystal structures of sintered copper nanoparticles:
    A molecular dynamics study. International Journal of Plasticity. 47, 65–79.'
  mla: 'Cheng, Bingqing, and Alfonso H. W. Ngan. “The Crystal Structures of Sintered
    Copper Nanoparticles: A Molecular Dynamics Study.” <i>International Journal of
    Plasticity</i>, vol. 47, Elsevier, 2013, pp. 65–79, doi:<a href="https://doi.org/10.1016/j.ijplas.2013.01.006">10.1016/j.ijplas.2013.01.006</a>.'
  short: B. Cheng, A.H.W. Ngan, International Journal of Plasticity 47 (2013) 65–79.
date_created: 2021-07-15T14:27:44Z
date_published: 2013-08-01T00:00:00Z
date_updated: 2023-02-23T14:04:30Z
day: '01'
doi: 10.1016/j.ijplas.2013.01.006
extern: '1'
intvolume: '        47'
language:
- iso: eng
month: '08'
oa_version: None
page: 65-79
publication: International Journal of Plasticity
publication_identifier:
  issn:
  - 0749-6419
publication_status: published
publisher: Elsevier
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'The crystal structures of sintered copper nanoparticles: A molecular dynamics
  study'
type: journal_article
user_id: 6785fbc1-c503-11eb-8a32-93094b40e1cf
volume: 47
year: '2013'
...