As a common detrimental element in Al-Si cast alloy, Fe can be effectively removed by Fe-containing intermetallic separation in the alloy melt. However, the thermodynamic formation mechanism and growth morphology evolution of high separable Fe-containing intermetallic have not been investigated and clarified in detail until now. In this study, thermodynamic calculation, three-dimensional (3D) growth morphology and crystal structure were characterized to investigate the effect of Mn and Cr on morphology evolution, crystal structure and precipitation temperature of Fe-containing intermetallics. It is demonstrated that the addition of Mn and Cr can increase the precipitation temperatures of Fe-containing intermetallics in melt, and also result in the variation of crystal structures from monoclinic γ-AlFeSi to cubic α-AlFeMnCrSi phases. Moreover, the addition of Mn and Cr significantly changes the morphology of Fe-containing intermetallics from plate-like to cubic shapes. α-AlFeMnCrSi phase precipitated at high temperature exhibits the same structural basis as α-Al₉Mn₂Si₂. The Fe-containing phase of cubic structure provides higher thermo stability which is in favor of its sufficient precipitation and separation.

作为Al-Si铸造合金中常见的有害元素，可以通过合金熔体中含Fe的金属间分离有效地去除Fe。然而，到目前为止，尚未对高分离度含铁金属间化合物的热力学形成机理和生长形态演变进行详细研究。在这项研究中，通过热力学计算，三维（3D）生长形态和晶体结构进行了表征，以研究锰和铬对含铁金属间化合物的形态演变，晶体结构和析出温度的影响。结果表明，Mn和Cr的添加可以提高熔体中含铁金属间化合物的析出温度，并且还导致晶体结构从单斜晶γ-AlFeSi转变为立方α-AlFeMnCrSi相。此外，Mn和Cr的添加显着改变了含铁金属间化合物的形态，从板状变为立方体。高温析出的α-AlFeMnCrSi相与α-Al具有相同的结构基础₉ Mn ₂ Si ₂。立方结构的含铁相具有较高的热稳定性，这有利于其充分的沉淀和分离。