<p>Rare earth elements (REEs) have garnered significant attention in the realm of aluminum alloy research due to their remarkable ability to enhance the physical and mechanical properties of aluminum alloys. In the present work, an effort has been made to produce Al–(Ce/La)–Mg alloy by direct metallothermic reduction of CeO₂ and La₂O₃, respectively, which are considered as the byproducts of heavy rare earth extraction. The developed alloys were characterized using X-ray diffraction, optical microscope, and scanning electron microscope to confirm the phases. Thermal analyses of the sample were performed using a differential thermal analyzer and thermo-mechanical analyzer to report on the solidus/liquidus temperature and coefficient of thermal expansion. The structural and microstructural studies reveal the presence of FCC α-Al matrix and (Al₁₁Ce₃/Al₁₁La₃) phase in Al–(Ce/La)–Mg alloy, respectively. The alternate eutectic lamellae of FCC-Al + Al₁₁Ce₃ and FCC-Al + Al₁₁La₃ were also observed, which indicated the superior casting characteristics of the alloys. This study envisages an effective way to produce rare earth-added Al alloys directly using CeO₂ and La₂O₃.</p> Graphical Abstract <p></p>