Properties of Ti/TiC Interfaces from Molecular Dynamics Simulations

Titanium carbide is used as a primary component in coating materials, thin films for electronic devices, and composites. Here, the structure of coherent and semicoherent interfaces formed between close-packed TiC (111) and Ti (0001) is investigated in classical molecular dynamics simulations. The forces on the atoms in the simulations are determined using a newly developed TiC potential under the framework of the third-generation charge optimized many-body (COMB3) suite of potentials. The work of adhesion energies for the coherent interfaces is calculated and compared with the predictions of density functional theory calculations. In the case of relaxed semicoherent interfaces, a two-dimensional (2D) misfit dislocation network is predicted to form that separates the interface into different regions in which the positions of the atoms are similar to the positions at the corresponding coherent interfaces. After the interface is annealed at an elevated temperature, the climb of edge dislocations is activated which modifies the 2D misfit dislocation network and increases the work of adhesion. These findings can be used as inputs for sequential larger simulation models to understand and predict the macroscopic properties of TiC/Ti interfaces.