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采用金相显微分析、X射线衍射、扫描电子显微镜和室温拉伸试验,研究了合金元素Zn、Gd对Mg-Zn-Gd合金铸态组织和力学性能的影响。结果表明,当Zn含量不变时,随着Gd含量的增加,合金中的第二相依次从准晶相(I相)+Mg7Zn3相、I相到I相+W相转变,二次枝晶臂间距明显减小,晶粒细化,晶间组织也由颗粒状、细线状向封闭的网状转变;当保持x(Zn)/x(Gd)=5.8不变时,合金第二相的组成不变,枝晶相分布更加细密,第二相也随之增多。拉伸测试表明,当Zn含量不变时,随着Gd含量的增加,合金的抗拉强度和伸长率均增加,但屈服强度先升高后降低;同比例增加Zn、Gd的含量,合金的强度升高,伸长率降低。
The effects of alloying elements Zn and Gd on the as-cast microstructure and mechanical properties of Mg-Zn-Gd alloy were studied by metallographic analysis, X-ray diffraction, scanning electron microscopy and tensile test at room temperature. The results show that with the increase of Gd content, the second phase in the alloy turns from quasicrystalline phase (I phase) + Mg7Zn3 phase, I phase to I phase + W phase, and the second dendrite The distance between the arms decreases obviously, the grains are refined and the intergranular structure changes from granular to fine-grained to the closed network; when keeping the value of x (Zn) / x (Gd) = 5.8, The composition of the same, dendritic phase distribution more detailed, the second phase also will increase. Tensile tests show that when the content of Zn is constant, with the increase of Gd content, the tensile strength and elongation of the alloy increase, but the yield strength first increases and then decreases. With the increase of the contents of Zn and Gd, Strength increases, elongation decreases.