Excessive iron in aluminum alloys forms compounds that weaken their strength and workability. Therefore, controlling the morphology of the Fe-rich phase is vital for developing strong, high-quality aluminum alloys. This research explores the controlled diffusion solidification (CDS) process, an innovative approach designed to optimize the morphology and distribution of the Fe-rich phase, thereby enhancing the alloy properties beyond what conventional methods can achieve. Specifically, the CDS process uniquely modifies the solidification behavior of the alloy, suppressing the growth of the primary Fe-rich phase and enhancing the overall properties. This demonstrating the ability of process to refine microstructural characteristics effectively. The experimental results confirm the presence of primary Si and Al3Fe in the CDS process samples. Consequently, the nucleation of Al3Fe in the precursor alloy leads to the concentration of Fe solutes reduce, impeding the nucleation and growth of the primary Fe-rich phase during the subsequent solidification process. The key factors are temperature difference between two mixed alloy and mass ratio of precursor alloys. The mass ratio influences the precipitation sequence of the precursor alloys, while the difference of temperature and concentration induces the undercooling necessary for nucleation. The study reveals that an optimal mass ratio of 4:1 in the CDS process achieves the best mechanical properties with a 73.78 % increase in ultimate tensile strength (UTS) and a 107.77 % increase in elongation (UL) compared to conventional casting. The findings provide a theoretical basis for controlling the Fe-rich phase evolution, significantly augmenting the performance of Al-Si-Fe alloys. The findings not only enhancing the optimizing fundamental reactions in the CDS process for other alloy systems but also enriching the broader field of materials science.

中文翻译：

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CDS工艺诱导富Fe相过冷调控Al-Si-Fe合金组织强化性能的机理


铝合金中过量的铁会形成化合物，削弱其强度和可加工性。因此，控制富铁相的形态对于开发高强度、高质量的铝合金至关重要。这项研究探索了受控扩散凝固（CDS）工艺，这是一种创新方法，旨在优化富铁相的形态和分布，从而提高合金性能，使其超出传统方法所能达到的水平。具体来说，CDS 工艺独特地改变了合金的凝固行为，抑制了初生富铁相的生长并提高了整体性能。这证明了该工艺有效细化微观结构特征的能力。实验结果证实了 CDS 工艺样品中存在初生 Si 和 Al3Fe。因此，前驱体合金中Al3Fe的形核导致Fe固溶浓度降低，阻碍了后续凝固过程中初生富Fe相的形核和生长。关键因素是两种混合合金之间的温差和前驱体合金的质量比。质量比影响前驱体合金的析出顺序，而温度和浓度的差异会导致成核所需的过冷。研究表明，CDS 工艺中的最佳质量比为 4:1，可实现最佳机械性能，与传统铸造相比，极限拉伸强度 (UTS) 提高 73.78%，伸长率 (UL) 提高 107.77%。这些发现为控制富铁相的演化提供了理论基础，显着提高了Al-Si-Fe合金的性能。 这些发现不仅增强了其他合金系统 CDS 过程中基本反应的优化，而且丰富了更广泛的材料科学领域。