Atomic insight on the electronic structure and interfacial bonding characterization of the Cu/TiC interface

Abstract

The interfacial bonding characteristics of ceramic reinforced phase and metal matrix in metal matrix composites have a significant impact on their strength. Herein, the interfacial bonding properties and alloy element doping of the Cu/TiC interface in TiC-reinforced Cu matrix composites with a stoichiometric ratio of TiC of 1:1 were investigated by atomistic DFT simulations. The analysis of twelve Cu/TiC interfacial models reveals that the TiC(111) in Cu/TiC interface with C-terminated is more stable than that of TiC(111) interface with Ti-terminated due to the stronger covalent bonds formed by Cu-C. The Cu(110)/TiC(111)-C interface with the highest work of adhesion (2.871 J/m2) is the most stable interface among these Cu/TiC interfaces. Moreover, the Cu-Co/TiC interface has the highest (4.223 J/m2) compared to Cu/TiC, Cu-Ni/TiC, and Cu-Zn/TiC interfaces. And the Cu-Zn/TiC interface has the lowest (2.092 J/m2), which is even lower than that of the Cu/TiC interface (2.306 J/m2). During interfacial tension, the Cu/TiC, Cu-Ni/TiC, and Cu-Zn/TiC interfaces start to fracture either at the interface layer or the sub-interface layer on the Cu side, while the Cu-Co/TiC interface begins to fracture within the Cu slab. The Cu-Co/TiC interface has the highest tensile strength of 20.12 GPa at14% strain compared to Cu/TiC (14.76 GPa), Cu-Ni/TiC (16.35 GPa), and Cu-Zn/TiC (15.30 GPa) interfaces, which is attributed to the strengthening of both the interface and sub-interface by Co doping. Thus, Co doping in the Cu matrix significantly strengthens the Cu/Ti interfacial bonding, Ni doping has a weaker strengthening effect, and zinc doping weakens the interfacial bonding.