The microstructures and mechanical properties, especially the contribution of individual strengthening mechanisms, of Mg–10Gd–0.4Zr alloy with the partial substitution of Gd with Nd are studied. The results show that Mg₁₂Nd phases appear in the as‐cast alloys when substituting Gd with Nd, and the volume fraction of the secondary phase increases with increasing Nd content. After solution heat treatment, secondary phases fully dissolve into α(Mg) matrix except for Mg–5Gd–5Nd–0.4Zr alloy, which is attributed to a high Nd content in that alloy, beyond the maximum solubility of Nd in Mg. Age‐hardening curves indicate that substituting Gd with Nd shortens the incubation time and improves the peak hardness. The peak‐aged Mg–7Gd–3Nd–0.4Zr alloy shows improved mechanical properties with the yield strength, ultimate tensile strength, and elongation of 195 MPa, 294 MPa, and 3.9%, respectively, which is attributed to the dense β″ and β′ precipitates formed during aging. Furthermore, the contributions of individual strengthening mechanisms in Mg–Gd–Nd–Zr alloys after different heat treatments are calculated, and the results show that the substitution of Gd with Nd significantly enhances the contribution of precipitation strengthening, especially in peak‐aged Mg–7Gd–3Nd–0.4Zr alloy.

中文翻译：

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Gd和Nd替代对Mg-10Gd-0.4Zr合金的组织和力学性能的影响

研究了Mg-10Gd-0.4Zr合金中Gd部分被Nd取代的显微组织和力学性能，尤其是单个强化机理的作用。结果表明，Mg ₁₂用Nd代替Gd时，铸态合金中会出现Nd相，并且第二相的体积分数随Nd含量的增加而增加。固溶热处理后，除Mg-5Gd-5Nd-0.4Zr合金外，第二相完全溶解在α（Mg）基质中，这归因于该合金中Nd含量高，超过了Nd在Mg中的最大溶解度。时效硬化曲线表明，用Nd代替Gd可以缩短孵育时间并提高峰值硬度。峰值时效的Mg-7Gd-3Nd-0.4Zr合金显示出改善的机械性能，屈服强度，极限抗拉强度和伸长率分别为195 MPa，294 MPa和3.9％，这归因于致密的β ”和β'在老化过程中形成沉淀。此外，计算了不同热处理后Mg-Gd-Nd-Zr合金中单个强化机制的贡献，结果表明，用Nd替代Gd可以显着增强沉淀强化的贡献，特别是在峰值时效Mg- 7Gd–3Nd–0.4Zr合金。