Bonding Properties of the Graphene/Aluminum Interface with Transition Metal Coating: A First-Principles Study

Graphene has excellent mechanical, electrical and optical properties, which make it an ideal reinforcement phase for aluminum matrix composites. However, graphene is easy to agglomerate and has poor wettability with the aluminum matrix, resulting in unsatisfactory effects when added to the aluminum matrix. In this paper, the effects of transition metals (Cu, Ni, Co) on the bonding properties at the graphene/aluminum interface were systematically investigated using first-principles calculations. The computational results reveal significant differences in the effects of various metals and their crystal plane orientations on interface stability and bonding strength. Among Cu, Ni, Co coatings, Co exhibits the most pronounced modification effect. Its most stable Co(110) crystal plane forms an interface with Al(111)/Gr(0001), exhibiting the highest adhesion work of 3.755 J/m². This trend indicates that the interfacial bonding strength follows the order Co > Ni > Cu. The calculated density of states and differential charge density show that graphene primarily undergoes weak physical adsorption on the Cu(100) plane, with negligible charge transfer, resulting in limited enhancement of interfacial bonding. In contrast, nickel and cobalt modifications introduce strong chemical bonding. Simulated tensile tests reveal that the cobalt-modified interface, characterized by strong chemical bonding, exhibits optimal mechanical properties, achieving a tensile strength of 7.715 GPa and an elongation at break of approximately 21%. Compared to the clean Al(111)/Gr interface (4.329 GPa, 15%), this represents a strength enhancement exceeding 78%. The copper-coated interface, which primarily relies on physical adsorption, shows limited strength improvement (5.493 GPa) and exhibits brittle fracture behavior. Both nickel- and cobalt-coated interfaces demonstrate distinct ductile fracture characteristics.