Role of graphene morphology in aluminium matrix composites: a review

Graphene is a highly promising reinforcement for aluminium matrix composites (AMCs) due to its outstanding mechanical, thermal, and barrier properties. However, its reinforcing efficiency is strongly governed by lateral size, thickness, and number of layers, which control dispersion, interfacial bonding, load transfer, and microstructural evolution. This review critically examines how graphene dimensional characteristics influence the microstructural, mechanical, and corrosion behaviour of Al – graphene composites. The effects of graphene morphology on grain refinement, interfacial reactions, Al4C3 formation, and dominant strengthening mechanisms – including load transfer, Orowan looping, Hall – Petch strengthening, and thermal mismatch-induced dislocations – are analysed. The role of processing routes such as powder metallurgy, stir casting, friction stir processing, severe plastic deformation, and additive manufacturing in preserving or altering graphene dimensions is also evaluated. Key challenges and future strategies for optimizing graphene morphology and processing are identified to enable high-strength, corrosion-resistant Al – Gr composites.