In this study, graphene nanoplatelets (0.25 and 0.5 wt-%) reinforced aluminium matrix composites were synthesised. Microstructures of composites were investigated by X-ray diffraction, scanning electron microscope and transmission electron microscope. Hardness was measured according to the Vickers test method. Tensile tests were performed at both room (25 degrees C) and elevated temperatures (150 degrees C and 250 degrees C). Results showed that hardness was improved with direct addition of graphene. Microstructure of composites was free of macro defects. Yield and tensile strength behaviours of pure aluminium were increased with the addition of graphene especially at room temperature. Graphene-reinforced samples have higher compressive residual stress. From the outer surface to inner surface, transition from compressive to tensile residual stress was observed for samples.