Effect of Vacancy Defects of Graphene on the Interfacial Bonding and Strengthening Mechanism of Graphene/Al Composite

Abstract

The structure and properties of the graphene-Al interface change significantly when defects are present in graphene. However, the properties of different defective graphene-Al interfaces and the strengthening mechanism of the interface are not clear. In this paper, the interfacial structure of graphene-Al with different vacancy defect types has been investigated by first-principle calculations, and the interfacial bonding was calculated by quantifying the interfacial shear strength. The interfacial shear strengths of defect-free, single-vacancy, and double-vacancy were 0.02 GPa, 6.8 GPa, and 8.5 GPa, respectively. Based on the first-principles data and the differential idea, the calculation model of shear strength of graphene-Al interface with different defect contents was established. The role of vacancy defects on the enhancement of graphene-Al interface binding was elucidated. A load-transfer strengthening model containing interfacial shear strength was developed and modified by combining experimental and references data. The model was validated by graphene/Al composites with directly bonding interface.

Keywords: Graphene, Al matrix composite, interface, interfacial shear strength, load-transfer strengthening model.