Refining the Fe-Containing IMCs in Al-Fe Alloy Through a Heterogeneous Nucleation Interface for an Enhanced Ductility of Recycled Aluminum Alloys

The coarse Fe-containing intermetallics (IMCs) induced by excessive Fe levels seriously degrade the mechanical and corrosion properties of recycled aluminum alloys. Controlling the nucleation and growth behavior has been confirmed as effective in refining the Fe-containing intermetallics (IMCs) and enhancing the ductility of recycled aluminum alloys. In this work, the modification mechanism of Al–Ti–B in Al–2Fe alloy was systematically investigated by combining SEM microstructure, TEM characterization and DFT calculations. TEM observations reveal that TiB2 particles are preferentially embedded within Al13Fe4 phases, forming coherent or semi-coherent interfaces, which act as nucleation sites and facilitate the refinement and uniform distribution of Fe-containing IMCs. Interface property calculation results show that the Al13Fe4 (620)/TiB2 (011-1) interface exhibits lower lattice mismatch (4.4%) and interface energy, indicating stronger interfacial bonding and higher interface stability. The electronic structure results showed that the enhanced interface stability is attribute to the pronounced charge redistribution. Stable interface structure reduces the heterogeneous nucleation barrier and promotes refinement efficiency of Fe-containing ICMs. This study provides theoretical guidance for the refinement of Fe-containing impurity phases and high-performance sustainable recycling of aluminum alloy scrap.