# Synergistic effect of Al2O3-decorated reduced graphene oxide on microstructure and mechanical properties of 6061 aluminium alloy

## TL;DR

This study shows that adding Al2O3-decorated graphene improves the strength and hardness of aluminum alloy composites.

## Contribution

The novel use of Al2O3-decorated reduced graphene oxide prevents brittle phase formation and enhances mechanical properties in aluminum matrix composites.

## Key findings

- Al2O3/RGO is uniformly distributed and bonded in the Al6061 matrix without forming brittle Al4C3.
- Adding 0.1 wt% Al2O3/RGO increases tensile yield and tensile strength by 49% and 43%, respectively.
- The 0.1 wt% composite shows the best plastic deformation capability.

## Abstract

In this study, Al6061 alloy matrix composites reinforced Al2O3-decorated reduced graphene oxide (Al2O3/RGO) with 0.1, 0.3 and 0.5 weight present (wt%) were successfully fabricated using high energy ball milling and hot extrusion techniques. The microstructures of these Al2O3/RGO/Al6061 aluminum matrix composites (Al MMCs) were characterized. The results showed that Al2O3/RGO were uniformly distributed within the Al6061 matrix and tightly bonded to the matrix. Al2O3 encapsulation on RGO surface would prevent the formation of Al4C3 brittle phase in matrix, ensuring that there was no reaction between the reinforcement and the matrix Al6061. Tensile strength and Vickers hardness tests demonstrated that the mechanical properties of Al MMCs significantly increased with addition of Al2O3/RGOs. Remarkably, Al MMCs with 0.1 wt% reinforcement showed tensile yield and tensile strengths of 270 MPa and 286 MPa, respectively, which were 49% and 43% higher than those of pure Al6061 prepared using the same process. Furthermore, the 0.1 wt% Al2O3/RGO composite also showed the best plastic deformation capability in considering of the strength.