为了获得一种高质量的含有二十面体准晶相的准晶合金,采用金属型铸造方法制备了Mg-Zn-Y合金.利用扫描电子显微镜、能谱仪、X射线衍射仪和维氏硬度仪研究了Zn、Y元素对合金组织与性能的影响,并分析了准晶相的形成机制.结果表明,在普通凝固条件下准晶相可以直接在液相中形核并长大,合金硬度及准晶相的形貌、大小和分布与Zn、Y元素的含量密切相关.随着Zn含量的增加,Mg-xZn-4.5Y合金硬度逐渐增大,组织中的准晶相由花瓣状向条状转变,且层片状共晶及α-Mg相逐渐消失.随着Y含量的增加,Mg-48Zn-yY合金硬度逐渐增大,花瓣状准晶相数量逐渐增多,且层片状共晶组织变得更为致密.通过调节Zn、Y元素含量可以获得高质量准晶合金Mg-48Zn-13Y.%In order to obtain a high-quality quasicrystal alloy with icosahedron quasicrystal phase, the Mg-Zn-Y alloys were prepared with the permanent mold casting method. The influence of Zn and Y elements on the microstructures and properties of the alloys were investigated with scanning electron microscope ( SEM ) , energy dispersive spectrometer ( EDS ) , X ray diffractometer ( XRD ) and Vickers hardness tester, and the forming mechanism of quasicrystal phase was analyzed. The results show that the quasicrystal phase can nucleate and grow directly from the liquid phase under the condition of normal solidification. In addition, the hardness of the alloys as well as the morphology, size and distribution of quasicrystal phase are closely related to the content of Zn and Y elements. With increasing the Zn content, the hardness of Mg-xZn-4. 5Y alloys gradually increases. The quasicrystal phase changes from the petal-like shape to strip shape, and the lamellar eutectic and α-Mg phase gradually disappear. With increasing Y content, the hardness of Mg-48Zn-yY alloys gradually increases. The amount of petal-like quasicrystal phase increases, and the lamellar eutectic becomes more compact. The high-quality quasicrystal alloy Mg-48Zn-13Y can be obtained through adjusting the Zn and Y contents.
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