Abstract We designed two types of Al-based alloy composites reinforced by η-Zn2Mg (hexagonal) and T-Al6Mg11Zn11 (cubic) intermetallic phases using monovariant eutectic reactions in the Al–Mg–Zn ternary system and then attempted to fabricate them using solidification. Thermodynamic assessment revealed two alloy compositions of Al–18Mg–36Zn and Al–22.5Mg–23.5Zn (at%) with the α-Al (fcc) phase reinforced with high fractions (>50%) of the η and T phases. Both alloys exhibited fine two-phase eutectic microstructures consisting of α/η and α/T phases, respectively. The morphology of the α-Al phase in the eutectic colonies varied from lamellae to fibers upon changing the neighboring intermetallic phase. These eutectic microstructures exhibit high stability at an elevated temperature of 300 °C. In addition, the size and spacing of the α-Al phase could be controlled by changing the cooling rate during solidification. The fabricated composites exhibited high hardness values exceeding 220 HV, which were much superior to those of conventional Al alloys. The calculated solidification path and component partitioning in the liquid phase during solidification provided insights into the solidification segregation of Zn element in the Al–18Mg–36Zn alloy. The Zn-enriched regions would enhance the local microstructural change at elevated temperatures, which confirmed by the microstructural observations of the alloy exposed at 300 °C.

中文翻译：

---

铝-镁-锌三元体系共晶反应制备金属间增强铝基合金复合材料的显微组织

摘要 我们在 Al-Mg-Zn 三元体系中使用单变共晶反应设计了两种类型的由 η-Zn2Mg（六方）和 T-Al6Mg11Zn11（立方）金属间相增强的铝基合金复合材料，然后尝试使用凝固法制造它们。热力学评估显示两种合金成分为 Al-18Mg-36Zn 和 Al-22.5Mg-23.5Zn (at%)，α-Al (fcc) 相用高比例 (>50%) 的 η 和 T 相增强。两种合金均表现出精细的两相共晶显微组织，分别由 α/η 和 α/T 相组成。在改变相邻的金属间相时，共晶群中的 α-Al 相的形态从片状到纤维变化。这些共晶微结构在 300 °C 的高温下表现出高稳定性。此外，α-Al 相的尺寸和间距可以通过改变凝固过程中的冷却速度来控制。制造的复合材料表现出超过 220 HV 的高硬度值，远优于传统铝合金。计算的凝固路径和凝固过程中液相中的组分分配提供了对 Al-18Mg-36Zn 合金中 Zn 元素凝固偏析的深入了解。富锌区域会增强高温下的局部微观结构变化，这通过暴露于 300°C 的合金的微观结构观察得到证实。计算的凝固路径和凝固过程中液相中的组分分配提供了对 Al-18Mg-36Zn 合金中 Zn 元素凝固偏析的深入了解。富锌区域会增强高温下的局部微观结构变化，这通过暴露于 300°C 的合金的微观结构观察得到证实。计算的凝固路径和凝固过程中液相中的组分分配提供了对 Al-18Mg-36Zn 合金中 Zn 元素凝固偏析的深入了解。富锌区域会增强高温下的局部微观结构变化，这通过暴露于 300°C 的合金的微观结构观察得到证实。