Mechanical properties of graphene-reinforced aluminium composite with modified substrate surface: a molecular...

Due to its extraordinary properties, graphene has been widely used as reinforcing nanofillers to enhance the mechanical properties of polymer- or metal-based composites. However, the weak interfacial interaction between the matrix and graphene is still a major bottleneck that considerably hinders its reinforcing effectiveness and efficiency. This study presents an atomistic study via molecular dynamics simulation on a chemical modification strategy where the aluminium (Al) substrate is modified with Al₂O₃ (with or without covalent bonds formed between Al₂O₃ and graphene) or Al₄C₃ to achieve significantly improved interfacial shear strength and overall mechanical properties of graphene-reinforced aluminium (Al/Gr) composites. Numerical results show that this strategy works very well and among the three cases considered, modifying Al substrate by Al₂O₃ without covalent bonds formed at the interface between Al₂O₃ and graphene produces the strongest interfacial interaction and the best mechanical properties. In the presence of covalent bonds, however, the reinforcing effect is adversely affected due to the sp²-sp³ bond transformation which partially degrades graphene. The present work provides, for the first time, valuable insight into the role of substrate surface modification on the mechanical performance of Al/Gr nanocomposites.