Structure–Property Relationships of CNT–Al2O3 Nano-Reinforced Al 6061 Matrix

Hybrid nanocomposites based on Aluminum 6061 (Al 6061) reinforced with carbon nanotubes (CNTs) and aluminum oxide (Al2O3) emerge as promising materials due to their ability to achieve simultaneous improvements in strength, thermal stability, and tribological performance. This study examines the structure–property relationships of CNT–Al2O3 nano-reinforced hybrid Al 6061, with particular emphasis on microstructural evolution and mechanical properties. The nanocomposites are fabricated via a powder metallurgy route, which enables optimized dispersion and homogeneous distribution of CNTs and Al2O3 within the aluminum matrix. Microstructural characteristics, interfacial bonding, and grain refinement are systematically analyzed using scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). Mechanical characterization demonstrates a marked enhancement in mechanical properties compared to Al 6061. The observed property improvements are attributed to synergistic strengthening mechanisms, including effective load transfer from the matrix to Al2O3 particles, CNT-induced grain refinement, and increased resistance to dislocation motion. These results establish a direct correlation between microstructural features and mechanical performance, highlighting the potential of CNT–Al2O3 reinforced Al 6061 hybrid nanocomposites for lightweight, high-strength applications in aerospace, automotive, and structural engineering industries.