Simultaneously enhanced strength and ductility of Al matrix composites through the introduction of intragranular nano-sized graphene nanoplates

Simultaneously achieving high strength and ductility is a critical issue for graphene reinforced aluminum matrix composites, which couldn't be resolved by the conventional mechanical milling-powder metallurgy technology due to the following reasons. On one hand, the low addition of graphene in the matrix traceable to its poor dispersibility limits the further strength improvement. On the other hand, the introduced graphene tends to distribute into grain boundaries rather than inside grains, which would result in stress concentrations at grain boundaries and localized strains, leading to the poor ductility of graphene/Al composites. In this work, intragranular nano-sized graphene nanoplates with high-content were dispersed in the matrix uniformly by a modified ball milling strategy, which induces that the strength and uniform elongation of the composites were simultaneously enhanced due to the improved work hardenability. Furthermore, the strengthening and toughening mechanisms were also discussed. This work offers a new insight into the fabrication and design of graphene/Al composites with both high strength and ductility.