Influence of short- to medium-range electronic and atomic structure on secondary relaxations in metallic glasses

B. Huang, C. C. Yuan, Z. Q. Wang, Y. Tong, Q. Wang, J. Yi, G. Wang, Q. F. He, C. H. Shek, Y. Yang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

1 Citation (Scopus)

Abstract

Unusual secondary relaxations were revealed in metallic glasses (MGs) recently. In this paper, we explore the structural origins of secondary relaxations in La-based MGs alloyed with different species of elements. With the combination of synchrotron X-ray diffraction and ab initio molecular dynamics simulations, solute-atom-centered clusters with a string-like type of medium-range order are found in the MGs, the formation of which leaves dispersed low-electron-density regions. It is found the activation energy of fast secondary relaxation increases with the reduction of low-electron-density regions, while slow secondary relaxation relates to the distance of La in next nearest La-La atomic pairs and the size of the string-like solute-atom-centered clusters. The phenomena are interpreted within the framework of the generalized Maxell model and free volume model. Our results demonstrate fast secondary relaxation as the activation of a small concentration of liquid-like regions with extremely low viscosities preceding slow secondary relaxation, and provide evidence for the correlation of secondary relaxations with short- to medium-range electronic and atomic structure in MGs.

Original languageEnglish
Pages (from-to)88-100
Number of pages13
JournalActa Materialia
Volume196
DOIs
Publication statusE-pub ahead of print - 12 Jun 2020
Externally publishedYes

Keywords

  • Atomic cluster
  • Low-electron-density region
  • Metallic glass
  • Secondary relaxation
  • Synchrotron X-ray diffraction

ASJC Scopus subject areas

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

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