Investigation of Microstructural, Hardness, and Tensile Response of Stir Cast AA7075 Composite

The current investigation focuses on evolution of the microstructural, hardness, and tensile properties of cast MMCs using AA7075 alloy reinforced with nano- and micro-sized Al2O3 particles. To characterize these composites, scanning electron microscopy, optical microscopy, hardness tests, and tensile responses were employed for four dissimilar combinations. The metallographic examination revealed that both nano- and micro-sized particles were uniformly distributed within the matrix. The hardness exhibited a gradual increase with the higher weight percentage of reinforcement in the AA7075alloy. The tensile properties of the hybrid composites were significantly influenced by dislocation density, arising from thermal mismatches between the reinforcement and the matrix, as well as the presence of porosity.