Crystal structures, growth characteristics, and transformation of the precipitates in a Mg-7Gd-5Y-1Nd-2Zn-0.5Zr (wt.%) alloy aged at 200 °C for various durations were investigated using transmission electron microscopy (TEM) and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). A detailed Mg-Gd type precipitation sequence for Mg-Gd-Y-Nd-Zn alloys was proposed as follows: supersaturated solid solution → solute clusters → zigzag GP zones + β′′(I) → β′ → β′+ protrusions/joints → pre-β₁ → β₁ → β. Solute clusters formed in the early stage of aging consisted of one or more rare-earth (RE)/Zn-rich atomic columns with different configurations. RE/Zn-rich solute clusters grew into zigzag GP zones and β′′(I) as aging time extending. The paired-zigzag GP zones might grow up to be β′ precipitates directly. In the peak- and plat-aging stages, the number of solute clusters in the matrix decreased until they disappeared, and most existed as zigzag arrays and super hexagons. Protrusions formed at the end of β′ at an angle of 120°, then grew into joints when two different β′ variants encountered together. Protrusions/joints comprise zigzag arrays, super-hexagons, β′_F, β′′(II), β_T, and hybrid structures rich in solute atoms, and act as catalysts for the growth of the β′ variants. Larger β′ grow by joints consumption while smaller β′ precipitates dissolve to form joints. β₁ precipitates essentially evolve from pre-β₁ precipitates, with four-point diamond structures formed by RE/Zn atomic substitution and atomic migration based on the original α-Mg structure.

使用透射电子显微镜 (TEM) 和高温研究了在 200 °C 下时效不同时间的 Mg-7Gd-5Y-1Nd-2Zn-0.5Zr (wt.%) 合金中的晶体结构、生长特征和析出物转变。角环形暗场扫描透射电子显微镜（HAADF-STEM）。提出了 Mg-Gd-Y-Nd-Zn 合金的详细 Mg-Gd 型析出顺序为：过饱和固溶体 → 溶质团簇 → 锯齿状 GP 区 + β′′(I) → β′ → β′+ 突起/关节 → 前β ₁  → β ₁ → β。老化早期形成的溶质簇由一个或多个具有不同构型的稀土（RE）/富锌原子柱组成。随着老化时间的延长，富RE/Zn溶质团簇生长成锯齿状的GP区和β''(I)。成对的锯齿状GP区可能直接长大为β'沉淀。在峰时效和平台时效阶段，基质中溶质团簇的数量减少直至消失，大部分以锯齿形阵列和超六边形形式存在。β'末端以120°角形成突起，当两个不同的β'变体相遇时，突起会长成接头。突出物/接头包括锯齿形阵列、超六边形、β′ _F、β′′(II)、β _T，以及富含溶质原子的杂化结构，并充当β'变体生长的催化剂。较大的β'通过接头消耗而生长，而较小的β'沉淀物溶解形成接头。β ₁析出物本质上是由前β ₁析出物演化而来，在原有的α-Mg结构的基础上，通过RE/Zn原子取代和原子迁移形成四点金刚石结构。