Multi-layer graphene reinforced aluminum – Manufacturing of high strength composite by friction stir alloying

Abstract

The paper reports manufacturing of a multi-layer graphene embedded composite of aluminium alloys by direct exfoliation of graphite into graphene with the help of Friction Stir Alloying (FSA). The formation of this nano-composite and optimization of the process parameters led to an approximately two-fold increase in the strength, without loss in ductility, due to the dispersion of the graphene in aluminium. The manufacturing process is scalable and cost effective as it uses graphite powder and aluminium sheets as the raw materials. The presence of graphene layers in the metal matrix was confirmed using Raman spectroscopy as well as TEM. The graphene sheet thickness was measured using AFM after extracting it from the composite. Molecular dynamic simulation results reveal the evolution of newer structures and defects that have resulted in the enhanced properties of the nano-composite. These findings open up newer possibilities toward efficient and scalable manufacturing of high-strength high-ductility metal matrix based graphene nano-composites.