Impact of the structural state on the mechanical properties in a Zr-Co-Al bulk metallic glass

J. C. Qiao, J. M. Pelletier, C. Esnouf, Y. Liu, H. Kato

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)

Abstract

This paper reports on the use of differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and nanoindentation technique to investigate atomic mobility in Zr56Co28Al16 bulk metallic glass in the as-cast state, after thermal annealing and after cold rolling. From the DMA results together with nanoindentation data point of view, the atomic mobility is significantly modified by the thermo-mechanical history. On the one hand, atomic mobility in bulk metallic glass is reduced after physical aging or crystallization. On the other hand, the atomic mobility in metallic glass is enhanced by cold rolling. To analyze the atomic mobility in amorphous materials, a physical theory is introduced. This model invoked the concept of quasi-point defects, which correspond to the density fluctuations in the glassy materials. Correlated movements of atoms are assisted by these quasi-point defects and the correlation factor χ is connected to the concentration of these "defects" in metallic glasses: (i) physical aging and crystallization decreases the parameter χ and (ii) the concentration of defects augments via plastic deformation (i.e. cold-rolling), suggesting that the correlation factor χ reflects the atomic mobility for glassy materials in a quantitative manner. This correlation bridges the gap between the mechanical properties on macroscopic scale and atomic mobility in microstructural regions in metallic glasses.

Original languageEnglish
Pages (from-to)139-149
Number of pages11
JournalJournal of Alloys and Compounds
Volume607
DOIs
Publication statusPublished - 2014 Sep 15

Keywords

  • Atomic mobility
  • Bulk metallic glass
  • Dynamic mechanical analysis
  • Nanoindentation
  • Quasi-point defects

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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