Nano icosahedral quasicrystalline phase in Zr65Al7.5Ni10Ag17.5 quaternary glassy alloy

Citation
J. Saida et al., Nano icosahedral quasicrystalline phase in Zr65Al7.5Ni10Ag17.5 quaternary glassy alloy, MATER TRANS, 42(8), 2001, pp. 1493-1496
Citations number
15
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Material Science & Engineering
Journal title
MATERIALS TRANSACTIONS
ISSN journal
1345-9678 → ACNP
Volume
42
Issue
8
Year of publication
2001
Pages
1493 - 1496
Database
ISI
SICI code
1345-9678(200108)42:8<1493:NIQPIZ>2.0.ZU;2-2
Abstract
A nano icosahedral quasicrystalline phase was confirmed as the primary prec ipitation phase in the melt-spun Zr65Al7.5Ni10Ag17.5 quaternary glassy allo y with a two-stage crystallization process, The onset temperature of the fi rst exothermic peak is 704 K at a heating rate of 0.67 Ks(-1), Although no significant X-ray diffraction peaks were observed in the sample annealed at 705 K, we confirmed the formation of the icosahedral phase by nano beam el ectron diffraction using FE-TEM. The icosahedral particles have an extremel y fine grain size in the diameter range of 2 to 4 nm. In addition to the ic osahedral phase, the nano crystalline particles corresponding to Zr2Ag and/ or fcc-Zr2Ni structures are also observed in the annealed sample. The secon d exothermic peak denotes the transition from the nano icosahedral to the c rystalline phase of Zr2Ag, fcc-Zr2Ni and Zr4Al3. The formation of the nano icosahedral phase as the primary phase is due to a high nucleation rate and strongly implies the existence of an icosahedral short-range order in the glassy state.