为了研究添加Yb元素对变形镁合金的作用，本工作研究了Yb含量(0%~1.0%，质量分数)对Mg-9Gd-4Y-1.2Zn-0.3Zr (GWZK)合金微观组织、室温和高温力学性能的影响。对固溶、挤压和时效处理后镁合金样品进行力学性能测试和微观组织表征。结果表明，GWZK-0.2Yb合金综合力学性能最佳，室温下屈服强度为456 MPa，抗拉强度为509 MPa，与GWZK-0Yb合金相比其屈服强度提高了约45 MPa。GWZK-0.2Yb合金在250 ℃高温下也具有326 MPa的高屈服强度和10.6%的高延伸率，与GWZK-0Yb合金相比实现了强塑性的协同提升。微观组织分析结果表明，微量Yb (0.2%)的添加抑制了合金中长周期堆垛有序(LPSO)相的形成，并促进了后续时效过程中β′和γ′相的析出，其强度提升主要来源于时效后α-Mg基体内的层状LPSO、致密析出的β′和γ′相。中等含量Yb (0.5%)的添加同时降低了合金的室温和高温延伸率。当Yb含量为1.0%时，GWZK合金的室温及高温强度和塑性同时降低，主要因为引入了更多的β相，减少了合金后续时效过程中析出的β′和γ′相的数密度。

To examine the effects of Yb addition on wrought Mg alloys, this study evaluates the influence of Yb content (0%-1.0%, mass fraction) on the microstructure, room-temperature, and high-temperature mechanical properties of the Mg-9Gd-4Y-1.2Zn-0.3Zr (mass fraction, %) alloy (GWZK). Mechanical performance tests and microstructural characterizations were conducted on alloy samples after solid solution treatment, extrusion, and aging. The results reveal that the GWZK-0.2Yb alloy exhibits superior mechanical properties, achieving tensile yield strength (TYS) of 456 MPa, which is an increase of approximately 45 MPa compared to the Yb-free GWZK-0Yb sample, and an ultimate tensile strength of 509 MPa. Furthermore, at 250 ^oC, the GWZK-0.2Yb alloy demonstrates a high yield strength of 326 MPa and ductility of 10.6%, indicating a synergistic improvement in strength and plasticity relative to the Yb-free sample. Microstructural analysis shows that the addition of 0.2%Yb suppresses the formation of long-period stacking ordered (LPSO) phases in the GWZK alloy while promoting the precipitation of β′ and γ′ phases during aging. The enhancement in strength is primarily attributed to the lamellar LPSO within the α-Mg matrix post-aging, as well as the dense precipitation of β′ and γ′ phases. However, increasing the Yb content to 0.5% reduces ductility at both room and high temperatures, primarily due to the high volume fraction of brittle β phases. Further increasing the Yb content to 1.0% leads to simultaneous decrease in strength and ductility at both temperature ranges. This degradation is attributed to the increased presence of the β phase, which reduces the number density of β′ and γ′ phases precipitated during the aging of the GWZK-1.0Yb alloy.