First-Principles Study of the Interfacial Wetting Behavior of MXene/Cu Composites

MXene, as a reinforcing material, can effectively improve the mechanical properties of Cu matrix composites. However, the presence of oxygen functional groups on the surface of MXene makes the interface between MXene and Cu matrix poorly wetted, which leads to brittle fracture of MXene/Cu composites after a certain stretching. In this paper, three kinds of interfaces, Ti₃C₂/Cu-(111), Ti₃C₂O₂/Cu-(111), and Ti₃C₂/Cu-(111)@Ni, were constructed based on the density functional theory using the first-principles calculation method. The inhibition behavior of oxygen functional groups on the interfacial wetting of MXene/Cu composites and the improvement mechanism of Cu matrix doped with Ni elements on the interfacial wetting of MXene/Cu composites were investigated. The results show that the Ti₃C₂/Cu-(111)@Ni interface has the largest charge transfer, followed by the Ti₃C₂/Cu-(111) interface, and the Ti₃C₂O₂/Cu-(111) interface has the smallest charge transfer. In the Ti₃C₂/Cu-(111)@Ni interface, Ni-Ti metallic bonds are formed. In the Ti₃C₂/Cu-(111) interface, Cu-Ti metallic bonds are established. In contrast, when -O functional groups are present at the Ti₃C₂O₂/Cu-(111) interface, the charge repulsion between Cu and O atoms is unfavorable for interfacial bonding. Whereas the Cu atoms at the Ni-doped interface form stronger Ni-Ti bonds due to the increase in local charge rearrangement, which in turn enhances the wettability properties of the interface. This study provides theoretical support for further understanding of the strengthening mechanism of MXene/Cu composites, as well as a feasible way to design high-performance MXene/Cu composites.