Nanocrystallization of Zr-Cu-Ni-Al-Au glassy alloys during severe plastic deformation

Masahiro Yamada, Ryo Kamisato, Tohru Yamasaki, Hiroki Adachi, Koichi Tsuchiya, Yoshihiko Yokoyama

Research output: Contribution to journalConference article

3 Citations (Scopus)

Abstract

A study has been carried out into the formation of nanocrystalline grains during high-pressure torsion (HPT) deformation of Zr65Cu17Ni5Al10Au3 bulk alloys prepared using tilt casting. As a preliminary to this, X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analyses were carried out on as-cast Zr65+xCu17-xNi5Al10Au3 (x=0∼5 at.%) and Zr65Cu20Ni5Al10Au3 alloys, in order to determine the effect on the microstructure of the excess Zr content x and the presence of Au. From the XRD patterns, it was determined that all of the alloys had a metallic glassy nature. For Zr65Cu17Ni5Al10Au3, the DSC results indicated the presence of a wide supercooled liquid region between the glass transition temperature (Tg) of 644 K and the crystallization temperature of 763 K, where the stable body-centered tetragonal Zr2Cu phase was formed. In contrast, for the Zr65+xCu17-xNi5Al10Au3 alloys, precipitation of an icosahedral quasicrystalline phase (I-phase) was observed in the supercooled liquid region at about 715 K. HPT deformation of the Zr65Cu17Ni5Al10Au3 alloys was carried out under a high pressure of 5 GPa. Both as-cast specimens and those annealed at Tg-50 K for 90 min were used. Following a single HPT rotation (N=1), transmission electron microscopy identified the presence of face- centered cubic Zr2Ni precipitates in the as-cast alloy, with a size of about 50 nm. For the annealed alloy, a high density of I-phase precipitates with sizes of less than 10 nm was observed following HPT with N=10, indicating that the combination of severe plastic deformation and annealing is effective at producing extremely small grains.

Original languageEnglish
Article number012167
JournalIOP Conference Series: Materials Science and Engineering
Volume63
Issue number1
DOIs
Publication statusPublished - 2014 Jan 1
Event6th International Conference on Nanomaterials by Severe Plastic Deformation, NanoSPD 2014 - Metz, France
Duration: 2014 Jun 302014 Jul 4

Keywords

  • Zr-Cu-Ni-Al-Au
  • glassy alloys
  • high-pressure torsion
  • nanocrystallization

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)

Fingerprint Dive into the research topics of 'Nanocrystallization of Zr-Cu-Ni-Al-Au glassy alloys during severe plastic deformation'. Together they form a unique fingerprint.

  • Cite this