In this study, we successfully prepared a Mg-6Zn-0.2Ca alloy by utilizing sub-rapid solidification (SRS) combined with hard-plate rolling (HPR), whose elongation-to-failure increases from ∼17% to ∼23% without sacrificing tensile strength (∼290 MPa) compared with its counterpart processed via conventional solidification (CS) followed by HPR. Notably, both samples feature a similar refined grain structure with an average grain size of ∼2.1 and ∼2.5 μm, respectively. However, the high cooling rate of ∼150 K/s introduced by SRS modified both the size and morphology of Ca₂Mg₆Zn₃ eutectic phase in comparison to those coarse ones under CS condition. By subsequent HPR, the Ca₂Mg₆Zn₃ phase was further refined and dispersed uniformly by severely fragmentation. Specially, the achieved supersaturation containing excessive Ca solute atoms due to high cooling rate was maintained in the SRS-HPR condition. The mechanisms that govern the high ductility of the SRS-HPR sample could be ascribed to following reasons. First, refined Ca₂Mg₆Zn₃ eutectic phase could effectively alleviate or avoid the crack initiation. Furthermore, excessive Ca solute atoms in α-Mg matrix result in the yield point phenomenon and enhanced strain-hardening ability during tension. The findings proposed a short-processed strategy towards superior performance of Mg-6Zn-0.2Ca alloy for industrial applications.

在这项研究中，我们通过使用亚快速凝固（SRS）结合硬板轧制（HPR）成功地制备了Mg-6Zn-0.2Ca合金，如果没有这种工艺，其延伸率从〜17％增加到〜23％。与通过常规固化（CS）和HPR处理的抗拉强度相比，可降低抗拉强度（〜290 MPa）。值得注意的是，两个样品均具有相似的细化晶粒结构，平均晶粒尺寸分别约为2.1和2.5μm。然而，与CS条件下的粗相相比，SRS引入的约150 K / s的高冷却速率改变了Ca ₂ Mg ₆ Zn ₃共晶相的尺寸和形貌。通过后续的HPR，Ca ₂ Mg ₆ Zn₃相进一步纯化，用严重碎裂均匀分散。特别地，在SRS-HPR条件下，由于高冷却速率而保持的过饱和Ca溶质原子过多。控制SRS-HPR样品高延展性的机理可归因于以下原因。首先，精炼的Ca ₂ Mg ₆ Zn ₃共晶相可以有效地减轻或避免裂纹的产生。此外，α-Mg基体中过多的Ca溶质原子会导致屈服点现象，并在拉伸过程中增强应变硬化能力。这些发现提出了一种针对Mg-6Zn-0.2Ca合金在工业应用中表现出卓越性能的短流程策略。