The Fabrication of Graphene-Reinforced Aluminum Composites by Powder Metallurgy and Uniaxial Pressing

This research studied the fabrication of graphene-reinforced aluminum composite via powder metallurgy and uniaxial pressing. The process started from mixing graphene with aluminum powder with various content of graphene (0.5, 1, 1.5, 2 and 4 wt.%) in acetone medium, followed by dispersion process at high frequency using an ultrasonic bath. The mixed composite powders were then formed into pellet and sintered at 600°C. The results showed that when graphene content in graphene reinforced aluminum composite is low (0.5wt.%, 1wt.% and 1.5wt.%), the hardness was enhanced. It was suspected that graphene could get into aluminum matrix and impede the grain growth of aluminum and dislocation movement. However, when excessive graphene content was added, graphene nanoplatelets tended to agglomerate, decreasing the hardness of composite. Similarly, the improvement of electrical and thermal conductivities was achieved with a low content of graphene. The well dispersion of graphene in aluminum matrix could facilitate the electron transport and to induce the pore reduction throughout the matrix.