Atomic rearrangements in metallic glass: Their nucleation and self-organization

W. D. Liu, Haihui Ruan, L. C. Zhang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

8 Citations (Scopus)

Abstract

The atomic rearrangement in metallic glass (MG) is a dynamics process. However, this problem has always been investigated within the quasi-static limit of the material. As such, the physical mechanisms of how the local rearrangements nucleate and coalesce into shear bands have not been fully understood. This study is to clarify the issue with the aid of a systematic molecular dynamics analysis. The present study unveils that the underlying mechanism of plastic deformation is through the rearrangement of atoms, characterized by the sudden surge in kinetic energy or strain rate of a local region, and that the shear banding is a stress-driven dynamic coalescence of these rearranging clusters, propagating in the speed of a shear wave. The ratio of the internal strain rate in forming a cluster to the applied strain rate is a measure of the severity of the local atomic rearrangement. The larger the severity, the easier the shear banding forms. The additional kinetic energy associated with the atom rearrangement in clustering is due to the descending of the potential energy after crossing the energy barrier. As temperature increases, the thermal vibration energy becomes larger than the barrier height, leading to thermal activations in MG and hence giving rise to a homogeneous deformation.
Original languageEnglish
Pages (from-to)6050-6060
Number of pages11
JournalActa Materialia
Volume61
Issue number16
DOIs
Publication statusPublished - 1 Sep 2013
Externally publishedYes

Keywords

  • Metallic glass
  • Molecular dynamics
  • Plasticity
  • Shear band
  • Strain rate

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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