Characterization of Al-5Ni-0.5Mg/x (Al2O3-GNs) nanocomposites manufactured via hot pressing technique

Exfoliating graphite to graphene nanosheets by mechanical ball milling with alumina, coating alumina particles with graphene layers to enhance their electrical and thermal properties, minimizing aluminum composite's production time, and improving the adhesion between the matrix and reinforcement were the aims of this study. Ball milling (BM) followed by electroless silver coating was used to prepare the (Al2O3-GNs) hybrid nanoparticles. A matrix sample from Al, 5 wt% Ni, and 0.5 wt% Mg was reinforced with different ratios of (Al2O3-GNs)/Ag nanoparticles up to 7.5 wt%. The cold and hot compaction technique was used to prepare the study samples. 550 °C and 50 min were the suitable parameters for fabricating the aluminum matrix composite. Microstructure investigation has been followed by chemical analysis, hardness, compressive strength, and electrical conductivity measurements. New intermetallic phases Al50Mg48Ni2, AlNi, and AlMg, have been formed during the powder consolidation by the hot-pressing process. The density of the Al-5Ni-0.5Mg (3.005 g/cm3) matrix was not significantly affected by the Al2O3/GN (3.907 g/cm3) reinforcement density. The 7.5 wt% Al2O3-GN reinforced composite exhibits the highest hardness. The electrical conductivity and the composites' compressive strength are also increased by 133% and 78%, respectively, for the 7.5 wt% sample.