Microstructures and mechanical properties of Mg–4.5Y–2.5Nd–1.0Gd–0.5Zr–xZn (x = 0, 0.5, 1.0, and 1.5; wt%) alloys under as-cast and peak-aged states were investigated in this work. The results indicate that the intermetallic phase components are closely dependent on Zn content. Under as-cast state, the dominant eutectic phase is Mg5RE in the alloys with 0 wt% and 0.5 wt% Zn additions while Mg5RE, 18R- and 14H-LPSO (long period stacking ordered) phases in the alloys with 1.0 wt% and 1.5 wt% Zn additions. After solution and peak-aging, the highest strength and hardness were obtained on the alloy with 0.5 wt% Zn addition. Transmission electron microscopy (TEM) characterizations revealed that there are denser and finer precipitates on basal (β′) and prismatic (γ″) planes, respectively. Therefore, the excellent mechanical performance of the alloy with 0.5 wt% Zn addition is mainly due to precipitation strengthening and grain boundary strengthening.

中文翻译：

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不同Zn添加量的Mg-4.5Y-2.5Nd-1.0Gd-0.5Zr合金的显微组织演变和时效行为

本工作研究了 Mg-4.5Y-2.5Nd-1.0Gd-0.5Zr-xZn（x = 0、0.5、1.0 和 1.5；wt%）合金在铸态和峰值时效状态下的显微组织和机械性能. 结果表明金属间相组分与Zn含量密切相关。在铸态下，锌添加量为 0 wt% 和 0.5 wt% 的合金中的主要共晶相为 Mg5RE，而锌添加量为 1.0 wt% 和 1.5 wt% 的合金中为 Mg5RE、18R-和 14H-LPSO（长周期堆积有序）相wt% Zn 添加量。在固溶和峰值时效后，添加 0.5 wt% Zn 的合金获得了最高的强度和硬度。透射电子显微镜 (TEM) 表征显示，基底 (β') 和棱柱 (γ") 平面上分别存在更致密和更细小的沉淀物。所以，