New group of stable icosahedral quasicrystals: structural properties and formation conditions
New group of stable icosahedral quasicrystals: structural properties and formation conditions
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DOI：
10.1016/j.jnoncrysol.2003.11.003
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发表时间：
2003-08
影响因子：
3.5
通讯作者：
T. Ishimasa;Y. Kaneko;H. Kaneko
中科院分区：
文献类型：
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作者：
T. Ishimasa;Y. Kaneko;H. Kaneko
对Zn-Mg-Sc、Cu-Ga-Mg-Sc和Zn-Mg-Ti合金中的二十面体准晶及其相应的1/1立方近似体的结构研究表明，这些准晶属于一个新的类似于Cd基准晶的结构群。该群的特征是不同于麦凯型和伯格曼型的三壳二十面体簇。原子团簇的存在已经从近似晶体Zn 17 Sc 3的结构模型中推导出来，其中团簇嵌入在所谓的“胶原子”的周期性网络中。密度测量表明，存在至少2.7锌原子在第一壳层的集群在这个近似。这三种准晶中的取代关系表明了Hume-Rothery规则在这类准晶形成中的重要作用。本文还报道了Zn-Mg-Yb合金中P型二十面体准晶的出现。
Structural studies on the icosahedral quasicrystals in Zn–Mg–Sc, Cu–Ga–Mg–Sc, and Zn–Mg–Ti alloys as well as their corresponding 1/1 cubic approximants, have revealed that these quasicrystals belong to a new structural group similar to Cd-based quasicrystals. This group is characterized by a triple-shell icosahedral cluster different from both Mackay- and Bergman-types. The presence of the atomic cluster has been deduced from the structure model of the approximant crystal, Zn17Sc3, in which the clusters are embedded in a periodic network of so-called ‘glue atoms’. Density measurement suggested the presence of at least 2.7 Zn atoms in the first shell of the cluster in this approximant. The substitutional relationship in these three quasicrystals indicates the important role of Hume-Rothery rule for the formation of this type of quasicrystal. The occurrence of a P-type icosahedral quasicrystal in Zn–Mg–Yb alloy is also reported.