Insights into atomic scale structure and interfacial fracture behaviors of Ti(0001)/Ti3Sn(0001) interface

The interfacial atomic scale structure and interfacial fracture characteristics of Ti(0001)/Ti3Sn(0001) interfaces have been investigated by performing first-principles calculations. The surface energies of five layer (2 × 2) Ti(0001) surface and (1 × 1) Ti3Sn(0001) surface are converged to 2.01 J/m2 and 1.63 J/m2, respectively. Four Ti(0001)/Ti3Sn(0001) interface models were considered based on different stacking sites. Thermodynamic stability of these models was determined by calculating adhesion work and interfacial energy. It is revealed that the interface model that the Ti atoms of Ti(0001) surface are deposited on the bridge of Ti–Sn bond of Ti3Sn(0001) surface along a axis is energetically favorable interface. The interfacial fracture behaviors of this model, including fracture work, critical stress, interfacial fracture toughness, and critical stress intensity factor, were predicted. In addition, the density of state analysis, electron density and electron density difference and Mulliken overlap populations were also analyzed. The results in this work provide the theoretical basis for understanding on the reinforcement mechanism of Ti3Sn in α-Ti matrix.