Change in local environment upon quasicrystallization of Zr–Cu glassy alloys by addition of Pd and Pt

The effects of Pd and Pt, which are known quasicrystal (QC)-forming elements, on the local atomic structure in Zr(70)Cu(30) glassy alloys are investigated. A QC phase precipitates from a glassy phase above a certain temperature by a cooperative-like motion of icosahedral clusters. Quasicrystallizati...

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Bibliographic Details
Published in:Journal of physics. Condensed matter 2011-05, Vol.23 (17), p.175303-9
Main Authors: Saida, Junji, Sanada, Takashi, Sato, Shigeo, Imafuku, Muneyuki, Ohnuma, Masato, Ohkubo, Tadakatsu, Hono, Kazuhiro, Matsubara, Eiichiro
Format: Article
Language:English
Subjects:
AMORPHOUS STRUCTURE
Clusters
Condensed matter: structure, mechanical and thermal properties
Cross-disciplinary physics: materials science
rheology
Exact sciences and technology
GLASSES
Glassy
Growth from solid phases (including multiphase diffusion and recrystallization)
Icosahedral phase
Materials science
Methods of crystal growth
physics of crystal growth
NUCLEI
Palladium
Physics
Quality control
Quasicrystals
Semi-periodic solids
Structure of solids and liquids
crystallography
Zirconium
ZIRCONIUM ALLOYS (50 TO 99 ZR)
Zirconium base alloys
ZIRCONIUM COPPERS
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Summary:The effects of Pd and Pt, which are known quasicrystal (QC)-forming elements, on the local atomic structure in Zr(70)Cu(30) glassy alloys are investigated. A QC phase precipitates from a glassy phase above a certain temperature by a cooperative-like motion of icosahedral clusters. Quasicrystallization is accompanied by a significant change in the local environment around the Zr atoms and a slight change around the noble metal. However, the local environment around the Cu atoms remains almost the same during QC formation. It is suggested that two types of icosahedral polyhedra exist in the glassy state: one has a relatively perfect icosahedral structure formed around the Zr atoms. The other is in a distorted state around the Cu atoms. We speculate that the medium-range order (i.e. QC nucleus) has a Zr-centered icosahedral cluster as its core, and the QC grows via aggregation of possible clusters in the initial stage. Pd or Pt atoms stabilize and/or connect individual Zr-centered icosahedral clusters, facilitating the formation of the nucleus and growth of the QC phase.
ISSN:0953-8984
1361-648X
DOI:10.1088/0953-8984/23/17/175303