中文摘要：

采用激冷铜模快淬的方法，在靠近Bergman线附近的富Mg区域的成分中获得了单相二十面体准晶相。利用X射线衍射仪、扫描电镜、场发射高分辨扫描电镜及透射电镜，分析了二十面体准晶相的微观组织、成分及原子簇结构。结果表明：快淬Al15Mg50Zn35合金中可以获得几乎单相的二十面体准晶相，能谱分析结果表明，其成分为39.76at％Mg，18.34at％A1，和41.90at％Zn：二十面体准晶相从熔体中直接形核并长大，呈现出典型的棱面枝晶形貌，其最快生长沿3次轴方向；同时，准晶晶粒还呈现出规则的六边形状，其尺寸约为0.2μm。二十面体准晶相的原子簇结构为具有二十面体对称性的五角十二面体，在每个五角面上可以看到微小的“凸起”。

英文摘要：

Almost an icosahedral quasicrstyal phase is obtained in the Mg-riehed region off the Bergman line by means of rapid quenching in a cool copper mould. The microstructures, chemical composition and atom cluster of the icosahedral phase are charactered by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, field-emission scanning electron microscopy and transmission electron microscopy （TEM）. It is found that the icosahedral quasicrystal phase is obtained with the composition of 39.76 at% Mg, 18.34 at% Al, and 41.90 at% Zn, which nucleates and grows directly from the melt with icosahedral symmetries. It exhibits a characteristic faceted dendritic growth with the fastest growth direction along a three-fold axes. At the same time, the regular hexagonal-polygon icosahedral quasicrystal grains with a size of 0.2 μm can also be observed. The atomic cluster of icosahedral phase is pentagonal dodecahedron with icosahedral symmetries and micro-lobes on the each faceted pentagonal face.