Moiré pattern features-dominated the inception of plasticity and strain hardening in graphene/Al multilayers

Abstract

This study presents a new insight on strengthening the mechanical properties of graphene-reinforced aluminum (graphene/Al) matrix composites through interface structure design, specifically the moiré pattern interface. Molecular dynamics (MD) simulations were performed to investigate the deformation behaviors in graphene/Al composites upon varying moiré pattern interface. The symmetry of the moiré pattern distribution about tensile axis and interfacial atomic shear strain are illustrated to be the dominant roles in dislocation nucleation behavior, resulting in a transition from dislocation-mediated deformation to deformation twinning. It is revealed that twins can be induced by adjusting the graphene/Al moiré pattern interface, which is achieved by rotating graphene 29.21° relative to Al. Consequently, twin nucleation, growth and twin-dislocation interaction contribute to a higher yield strength and enhanced strain hardening capability in graphene/Al system. The present study raises the possibility of producing twins in high stacking fault energy metal Al could by utilizing graphene/Al interfaces. Furthermore, the introduction of the deformation twinning strengthening mechanism in matrix Al serves to further strengthen the graphene/Al composites.