Tuning graphene/Ti composite interfaces: How alloying elements modify electronic structure and interfacial properties

Graphene/Ti composites have attracted significant attention from researchers owing to their exceptional strength, ductility, and impact resistance. However, the high chemical reactivity of titanium complicates the interfacial structure and presents challenges in the development of graphene/titanium composites. Consequently, it is crucial to investigate the microscopic mechanisms for modifying the graphene/titanium interface by introducing alloying elements. In this study, the thermodynamic stability, interfacial shear properties, and electronic structure of graphene/titanium interfaces doped with various alloying elements are evaluated using first-principles calculations. The results indicate that the alloyed graphene/Ti interface exhibits good thermodynamic stability in the ground state. Specifically, the graphene/Ti interface shows a greater tendency to form alloyed interfaces when doped with 5d metal elements such as Os, Re, or Ir. Furthermore, the incorporation of alloying elements significantly enhances the shear properties of the graphene/Ti interface. Notably, the Mn-alloyed graphene/Ti interface exhibits superior toughness, while the Ir-alloyed interface reveals a substantial increase in shear strength, primarily due to the strengthening of C–Ti covalent bonds.