中文摘要：

适用的 XRD， DTA， SEM 和 TEM 技术，团结微观结构上的调查和 Mg 富有的 Mg-28%Zn-2%Y (莫耳分率) 的团结顺序合金被执行。它被发现那，α - Mg 树突， Mg7Zn3 阶段和 icosahedral 伪水晶分阶段执行，在同样团结的合金共存 icosahedral 伪水晶，其结构是是一种以脸为中心的类型的 indentified，从发生在 416 ° C 的包晶体的反应发源。这包晶体的反应的主要阶段有 Mg20Zn66Y14 的作文，它是重合的， H 阶段是由 TSAI 报导了(Zn， Mg ) 5Y。而且，单个我阶段谷物形态学被观察，它的生长进化也被讨论。

英文摘要：

Applying XRD, DTA, SEM and TEM techniques, an investigation on the solidification microstructure and solidification sequence of Mg-rich Mg-28%Zn-2%Y （mole fraction） alloy was carried out. It is found that, a-Mg dendrites, Mg7Zn3 phase and icosahedral quasicrystal phase coexist in the as-solidified alloy, where the icosahedral quasicrystal, whose structure is indentified to be a face-centered type, originates from a peritectic reaction occurring at 416 ℃. The primary phase of this peritectic reaction has the composition of Mg20Zn66Y14, which is coincident with the H phase reported by TSAI as （Zn, Mg）5Y. Furthermore, the single I-phase grain morphology was observed and its growth evolution was also discussed.