Graphene oxide/Al composites with enhanced mechanical properties fabricated by simple electrostatic interaction and powder metallurgy

Abstract

Graphene has attracted great attention as an ideal reinforcement in Al matrix composites. However, there are still challenges limiting the performance of the composites, such as the homogenous distribution of graphene in Al matrices. In this paper, graphene oxide/aluminum (GO/Al) composites with enhanced mechanical properties were fabricated by electrostatic interaction and subsequent powder metallurgy method. Firstly, GO was homogenously coated on the surface of micro-sized spherical aluminum powders by electrostatic interaction between GO and aluminum in water/ethyl alcohol solution with a little HCl acid. Then the mixture of GO/Al composite powders with different GO content (0.15 wt%, 0.3 wt%, 0.6 wt%) were cold compacted and sintered at 580°Cfor 3 h. Compared with unreinforced Al, the composite with only 0.3 wt% GO achieved 73.9% enhancement in ultimate tensile strength, which was up to 167 MPa with elongation of 11.5%. Three points bending test was also carried out for composite with 0.3 wt% GO, and the flexural strength reached 224 MPa. Fractured morphology displayed a ductile break and graphene oxide pull-out was detected at the edges of dimples. It was expected that this work could offer a simple method to prepare graphene reinforced metal matrix composites.