Mg-Gd-Y-Zr alloys with high strength levels fall within narrow composition ranges. The present paper explains their composition rule by establishing the cluster-plus-glue-atom unit of Gd-containing Mg solid solution with the aid of Mg matrix and Mg₅Gd precipitate phase. First, based on the structural homologue between Gd-containing Mg solid solution and Mg₅Gd precipitate phase and in combination with our previously established method for calculating the glue atoms, [Gd-Mg₁₂]Mg₅ is obtained as the chemical unit of Gd-containing Mg solid solution. Then, seven compositions are designed using different combinations of this unit and that of pure Mg [Mg-Mg₁₂]Mg₃. After a systematic experimental investigation on the microstructure and mechanical property evolutions as a function of the unit proportions, it is revealed that the Mg-10.1Gd-3.3Y-0.9 Zr alloy, being issued from equi-proportion mixing of the two units, shows the strongest tendency of precipitation and reaches the highest strength of 374 MPa after aging. The composition and strength of this alloy are quite close to GW103 K which is well recognized for its general mechanical performance in Mg-Gd-Y-Zr system.

具有高强度水平的Mg-Gd-Y-Zr合金在狭窄的成分范围内。本文借助Mg基体和Mg ₅ Gd析出相，建立了含Gd的Mg固溶体的簇加胶原子单元，解释了它们的组成规律。首先，基于含Gd的Mg固溶体和Mg ₅ Gd沉淀相之间的结构同源性，并结合我们先前建立的计算胶原子的方法，获得[Gd-Mg ₁₂ ] Mg ₅作为Gd的化学单元。含镁固溶体。然后，使用该单元和纯Mg [Mg-Mg ₁₂ ] Mg _3的不同组合设计了七个组成。通过对组织和力学性能随单位比例变化的系统性实验研究，发现Mg-10.1Gd-3.3Y-0.9 Zr合金是由两种单位等比例混合而制得的，表明时效最强，时效后达到374 MPa。该合金的成分和强度非常接近GW103 K，该合金因其在Mg-Gd-Y-Zr系统中的一般机械性能而广为人知。