Adhesion strength, stability and electronic properties of TiB₂ reinforced copper matrix composites: A first principles study

The first principles method was utilized to study the interfacial properties of the TiB₂ reinforced copper matrix materials. The interfacial stabilities were studied initially via the works of adhesion and interfacial energies. According to the results, TT-OT (Ti-terminated TiB₂/Cu “OT” stacking) and BT-HCP (B-terminated TiB₂/Cu “HCP” stacking) were confirmed to be the most stable interfaces. The charge density distribution, charge density difference, electronic localization function and partial density of state were analyzed for TiB₂/Cu interfaces. The results indicate that Ti-terminated TiB₂(0001)/Cu(111) interfaces were more inclined to form the metallic bond, while the B-terminated TiB₂(0001)/Cu(111) interfaces were likely to form the ionic bond. Moreover, the interfacial elastic energy, interfacial fracture toughness and ultimate tensile tress were carried out to make clear of fracture mechanism of the TiB₂(0001)/Cu(111) interfaces. The TT-OT and BT-HCP were confirmed to be the two most stable interfaces due to their largest interfacial elastic energies. The computational ultimate tensile tress for Ti-terminated TiB₂(0001)/Cu(111) and B-terminated TiB2(0001)/Cu(111) interfacial models were 23 GPa and 25 GPa, respectively.