利用X射线衍射仪、扫描电镜并配合能谱分析研究了Mg-6Zn-3Y合金4 GPa超高压凝固组织。结果表明:在4 GPa超高压条件下凝固时,实验合金的凝固组织得到显著细化,基体α-Mg相的晶格间距有所减小;Zn在基体α-Mg中溶解度大幅提高,Y不溶于基体α-Mg;实验合金凝固组织中出现呈对称性的四瓣或六瓣花的初晶Y固溶体,该初晶花瓣形貌完整、尺寸较大,显示其充分自由生长;先发生的共晶反应的共晶组织为成“簇”分布的共晶团,共晶相呈点状或棒状;后发生的共晶反应的组织为离异共晶。超高压凝固显著地改变了实验合金的凝固过程。 The 4 GPa ultrahigh-pressure solidified microstructure of Mg-6Zn-3Y alloy was studied by X-ray diffraction, scanning electron microscopy and energy spectrum analysis. The results show that the solidification microstructure of the experimental alloy is significantly refined and the lattice spacing of the α-Mg phase matrix is ​​reduced when solidified under the condition of 4 GPa ultra-high pressure. The solubility of Zn in the matrix α-Mg is greatly increased and Y is insoluble In the α-Mg matrix, the primary Y solid solution with symmetry of four or six petals appears in the solidified microstructure of the experimental alloy. The primary flower petal has a complete morphology and large size, indicating that it is fully free-growing. The eutectic structure of the crystal reaction is a eutectic group distributed in “cluster ” with a eutectic phase having a dot or rod shape; the eutectic structure after the eutectic reaction is a divorced eutectic. Ultrahigh pressure coagulation significantly changes the solidification process of the experimental alloy.