Microstructural Changes and Mechanical Response of Aluminum-Based Composites Prepared with Dispersed CeO₂ Nanoparticles

Abstract

The effect of CeO2 nanoparticles on the microstructure of two different metal matrixes, AA2024 aluminum alloy and pure aluminum, were studied. The aluminum-based composites were synthesized by mechanical milling and subsequently sintering at 550°C under an argon atmosphere. The microstructural evolution of consolidated composites was evaluated by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The experimental results revealed that the addition of CeO2 nanoparticles in the AA2024 alloy produced a dispersed needle-like Ce-Cu-rich phase that reduces the hardness of samples after sintering. On the contrary, the dispersion of CeO2 in pure aluminum shows significant improvement of hardness in comparison with the reinforced and unreinforced AA2024 aluminum alloy. During the sintering, the CeO2 nanoparticles show higher chemical stability in the aluminum matrix in comparison with the AA2024 matrix.