中文摘要：

球形的 icosahedral 伪水晶的阶段(我阶段) 被在常规扔下面介绍 Ca 进 Mg-Zn-Y 合金获得条件。由于 Ca 的增加， Mg45Zn50Y4.5Ca0.5 主要我阶段，是稳定、同类地分布式的热力学的联盟者，被产生而不是十面体的伪水晶的阶段在团结过程期间：在团结微观结构的主要我阶段的形态学从像花瓣的(60 80 μ m ) 改变了到球形的(≤ 15 μ m ) 。当 Ca 的集体部分到达 0.05% 时，有最大的数量，最高的 spheroidization 率和最高圆形的度的球形的我阶段能被获得。由于改变的形态学和主要我阶段的减少的尺寸，同时， Mg-Zn-Y-Ca 主人合金的坚硬被减少。增强的微粒分阶段执行的球形的我阶段的申请为力量的改进和镁合金的坚韧提供大机会。

英文摘要：

Spherical icosahedral quasicrystalline phase （I-phase） was obtained by introducing Ca into Mg-Zn-Y alloy under conventional casting conditions. Due to the addition of Ca, Mg45Zn50Yn4.5Ca0.5 primary I-phase, which is thermodynamically stable and homogeneously distributed, was generated instead of decahedral quasicrystalline phase during the solidification process; the morphology of primary I-phase in the solidification microstructure changed from petal-like one （60-80 μm） to spherical one （≤ 15 μm）. When the mass fraction of Ca reaches 0.05%, sphericalI-phase with the largest quantity, highest spheroidization rate and highest circular degree can be obtained. Meanwhile, due to the changed morphology and the decreased size of primaryI-phase, the hardness of Mg-Zn-Y-Ca master alloy is reduced. The application of spherical I-phase as particulate reinforced phase provides great opporttmities for the improvement of strength and toughness of magnesium alloys.