Nanoscale icosahedral phase formation in Cu-based bulk glass formers

Dmitri V. Louzguine, Akihisa Inoue

Research output: Contribution to journalConference articlepeer-review

Abstract

Quaternary Cu55Zr30Ti10NM5 glassy alloys (NM= noble metal) prepared by rapid solidification of the melt and by copper mold casting are studied in the present work. Alloys ingots were prepared by arc-melting mixtures of pure metals in an argon atmosphere. Glass-forming ability, supercooled liquid region and devitrification behaviour of Cu-Zr-Ti-(Pd, Ag, Pt and Au) glassy alloys were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and isothermal calorimetry. A nanoicosahedral phase of about 3-10 nm in size is primarily formed in the Cu55Zr30Ti 10(Pd,Au)5 glassy alloys in the initial stage of the devitrification process. A multi-peak fitting by the Lorentzian function was used to separate the overlapped X-ray diffraction peaks. A direct evidence of the formation of the icosahedral phase was obtained using nanobeam diffraction in TEM. The results of the isothermal calorimetry data analysis indicate steady-state nucleation and 3-dimensional diffusion-controlled growth of nuclei. The quasilattice constant values of 0.495 nm and 0.496 nm obtained in Cu 55Zr30Ti10Pd5 and Cu 55Zr30Ti10Au5 glassy alloys, respectively, in the relationship with the average atomic diameter indicate that the icosahedral particles consist of rhombic triacontahedra. The icosahedral particles have a metastable nature and transform to the equilibrium phases through the intermediate crystalline phases. At the same time Pd and Au additions significantly expand the supercooled liquid region of the Cu-Zr-Ti glassy alloy. However, no icosahedral phase but the crystalline intermetallic compounds were primarily formed in the Cu55Zr30Ti 10(Ag,Pt)5 glassy alloys.

Original languageEnglish
Pages (from-to)47-52
Number of pages6
JournalJournal of Metastable and Nanocrystalline Materials
Volume20-21
DOIs
Publication statusPublished - 2004
EventProceedings of the 10th International Symposium on Metastable Mechanically Alloyed and Nanocrystalline Materials (ISMANAM-2002) - Foz do Ifuacu, Brazil
Duration: 2003 Aug 242003 Aug 28

Keywords

  • Bulk Glassy Alloy
  • Devitrification Behaviour
  • Nanoscale Icosahedral Phase
  • Supercooled Liquid Region

ASJC Scopus subject areas

  • Materials Science (miscellaneous)
  • Materials Science(all)
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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