Abstract: Low carbon footprint aluminum structure castings are the mainstream development direction of aluminum alloys in the future. Enhancing the Fe content tolerance upper limit in casting aluminum alloys is considered an effective way to promote the application of recycled aluminum production. In this work, it was found that with the Ce and TiCN NPs (nanoparticles) addition simultaneously to A356 alloys, the acicular Fe-rich phases (β-Al₅FeSi) which damages the properties can be changed into beneficial phases (core-shell heterostructures) for the alloy, and hence the mechanical properties of A356 alloys can be improved. The TiCN nanoparticles and rare element Ce play crucial roles in the formation of core-shell heterostructures. The formation mechanism of core-shell heterostructure was also systematically researched from the perspective of thermodynamics and kinetics. This study provides a simple and feasible strategy to eliminate the harmful effects of Fe impurity and contributes to the industrialization of low carbon footprint aluminum structure castings.

Key words: A356 casting aluminum alloys, Heterostructure, Carbon neutral, TiCN nano particles, Mechanical properties