Production and characterization of sustainable aluminium matrix composites reinforced with industrial waste materials via stir casting for lightweight and high-strength applications

The present research work deals with the fabrication and characterization of AMC-based composites through the addition of industrial wastes in the form of iron (Fe) and copper (Cu) particles by stir casting. The investigation covers their microstructure evolution, mechanical properties, and porosity. With the optimized stirring parameters adopted in the study, three composites were fabricated: as-cast scrap industrial aluminum alloy (SIAA), Al-Fe, and Al-Cu. Accordingly, the Al-Fe composite exhibited a higher tensile strength of 117.6%, which rose to 148 MPa from that of the as-cast SIAA with a value of 68 MPa. This is attributed to the presence of a refined microstructure, homogeneous dispersion of Fe particles, and subsequent intermetallic formation. Its ductility was compromised in the range of 0.5–1% elongation. The Al-Cu composite exhibited an intermediate strength of 95.36 MPa and demonstrated better ductility in the range of 3–3.5% elongation. However, it exhibited higher submicron porosity of 13.7% along with interfacial oxides, as revealed from SEM and elemental mapping. Microstructural studies further established that the superior performance of Al-Fe is attributed to the pore-free interfaces and the segregation of Fe-Si at the grain boundaries, whereas the limitations in case of Al-Cu arise due to the presence of nano-porosity and Cu-Mg-O clustering. These results demonstrate the feasibility and acceptability of waste-based reinforcement in AMC fabrication. Specifically, the Al-Fe composite emerges as a high-strength and sustainable class. This work contributes toward the development of eco-friendly composites by establishing a relation between processing parameters, interfacial chemistry, and associated mechanical properties. It also demonstrates promising information for industrial applications pertaining to lightweight engineering.