Abstract The proper alloy composition ranges for rheo-forming of Mg-RE alloy was obtained through thermodynamic calculations. The low frequency electromagnetic stirring (LFEMS) process was used to fabricate semisolid slurries of Mg-Gd-Zn series alloys, and the role of solute Gd content and the cooling rate in the LFEMS process were systematically investigated. Both the Gd content and cooling rate show effective influences on the microstructure of the Mg-Gd-Zn alloy semisolid slurries. Fine and spherical primary Mg phase can only be obtained by decreasing the cooling rate to less than 1.4 C°/min and increasing the solute Gd content to no less than 9 wt.%. The formation mechanism of non-dendritic morphology of primary Mg phase in Mg-Gd-Zn alloy was proposed to be the dendrite arm root re-melting induced by curvature undercooling and ripening induced by low cooling rate.

中文翻译：

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在半固态镁稀土合金浆料制备过程中非枝晶组织的形成：稀土含量和冷却速率的作用

摘要 通过热力学计算，得到了适合Mg-RE合金流变形成的合金成分范围。采用低频电磁搅拌（LFEMS）工艺制备Mg-Gd-Zn系列合金半固态浆料，系统研究了溶质Gd含量和冷却速率在LFEMS工艺中的作用。Gd 含量和冷却速度均对 Mg-Gd-Zn 合金半固态浆料的微观结构产生有效影响。只有通过将冷却速度降低到小于 1.4 C°/min 并将溶质 Gd 含量增加到不低于 9 wt.% 才能获得细小的球形初生 Mg 相。