Graphene oxide-reinforced aluminium-matrix nanostructured composites fabricated by accumulative roll bonding

Accumulative Roll Bonding (ARB) was used to fabricate Graphene Oxide-reinforced Al-matrix composites. Graphene Oxide reinforcement was suspended in a stabilized aqueous solution and applied, prior to each ARB cycle, through airgun spraying. Different concentrations (graphene oxide/milipore water) were used and for each concentration, samples produced have undergone up to 5 rolling cycles. Optical and electron scanning microscopies were used for microstructural characterization which revealed a non-homogenous deformation of the layers across the composite's thickness. Although the presence of graphene-oxide promoted an increase in the microhardness, higher values were obtained with its lowest concentration for similar samples. The number of ARB cycles and the direction of the tested sections also influenced the microhardness results since the 5-cycle samples and the rolling direction sections for all the samples achieved higher hardness results. Graphene Oxide revealed to be a major contributor to the increase of stiffness during bending of the tested samples.