First-principles calculation of graphene/titanium interface properties and investigation on the effect of Si and C solute elements on interface reactions

Alloying with elements such as Si and C can inhibit the reaction between graphene and the Ti matrix in graphene-reinforced titanium matrix composites (TMCs), allowing graphene to achieve the expected enhancement of the mechanical properties and wear resistance of TMCs. To investigate the mechanism by which Si and C alloying inhibits the reaction between graphene and the Ti matrix, this study employed first-principles calculations to analyze the effects of different atomic solid solutions on the interface properties of graphene/titanium (Ti). It was found that the synergistic electron-capturing ability of the co-dissolved Si and C atoms from Ti is stronger than that of either Si or C atoms in their respective single solid solution states. In addition, vacuum arc melting was used to fabricate few-layer graphene (FLG)/Ti-6Al-4V (TC4) composites with different atomic solid solutions. The degree of reaction between graphene and the Ti matrix in these composites was characterized. In the Raman spectra of the composites, the I D /I G ratio decreased sequentially from 0.725 in the graphene/Ti system to 0.712 in the system with only Si solid solution, 0.611 in the system with only C solid solution, and 0.517 in the system with Si and C co-solid solution. This is fully consistent with the results of the previous first-principles analysis: the co-solid solution of Si and C atoms exhibits the most significant inhibitory effect on the reaction between graphene and Ti.