Al基三元准晶相图的电子浓度特征

准晶是一种电子型金属间化合物，其形成及结构稳定性主要由电子浓度因素控制。三元准晶相图的电子浓度特征表明，三元准晶与其晶体学类似相一起位于一等电子浓度线附近，称为准晶等电子浓度线现象。同时，三元准晶与二元准晶的存在密切联系，它们同第三组元一起落在同一变电子浓度线上，称为准晶变电子浓度线现象，三元准晶的理想成分位于准晶等电子浓度线和准晶变电子浓度线的交点上，据此特征，区分了两种类型的Al-Ni-Fe三元十次准晶，它们的典型成分分别为：D-Al72.5Fe14.5Ni13(Al-Fe型）和D′-Al70.5Fe12Ni17.5(Al-Ni型）。

VALENCE ELECTRON CONCENTRATION FEATURES OF Al-BASED TERNARY QUASICRYSTALLINE PHASE DIAGRAMS

Quasicrystals (QCs) and their approximants are electron compounds. The present investigation on valence electron concentration feature in the Al-based ternary quasicrystalline phase diagrams showed that QCs and approximants are e/a-constant (constant valence electron concentration) phases, they are all located near a straight line with constant e/a ratio (e/a-constant line phenomenon). At the same time, it is noted that the ternary QCs, related binary ones and the third element are also located in one straight line (e/a-constant line phenomenon). The ideal composition of an ternary Al-based QC's is located at the crossing point of the e/a-constant and the e/a-variant line. According to this empirical rule, two typical compositions were obtained for decagonal AI-Ni-Fe QCs: D-Al72.5Fe14.5Ni13 and D'- A70.5Fe12Ni17.5 which correspond respectively to AI-Fe and AI-Ni binary QCs.