Investigation of microstructure and mechanical properties of Al2024-CNT nanocomposite produced by flake powder metallurgy process

Nowadayas, manufacturing of carbon nanotube reinforced aluminium matrix nanocomposites have been studied by many researchers. Different techniques have been used for possessing of Al-CNT nanocomposites. But, the powder metallurgy methods have been more attractive because of the lower temperature and better control of process. In the current research, the flake powder metallurgy route was used as a slurry based method to produce Al2024-CNT nanocomposite with 1.5wt.% CNT as reinforcement. Then, the initial compacted billets of Al2024 alloy and Al2024-CNT composites were produced by cold pressing of powders. They were sintered at 550 oC and the billets were hot extruded to produce rods with 10 mm in diameter. The produced samples were investigated by means of tension, compression, hardness, density measurement, XRD, and Raman tests. The uniform dispersion of CNTs within Al2024 powder was observed using FE-SEM. It was related to the merits of wet synthesis of composite powder. In Al2024-CNT sample, the yield and ultimate strength was increased about 28% in comparison with Al2024-O; It was also increased about 20% in yield strength and 15% in tensile strength compared with Al2024-T6 sample. After optimum sintering process, the relative density, hardness, and compressive strength of Al2024-CNT nanocomposite have been increased through hot extrussion to 95.6%, 90 HB, and 547 MPa, respectively. In addition to Al2Cu and Al2CuMg intermetallics in alloyed samples, Al4C3 carbide phase was proved to be formed after sintering in composite specimen.