Development and application of interatomic potentials to study the stability and shear strength of Ti/TiN and Cu/TiN interfaces

Abstract

A modified embedded atom method interatomic potential was developed to study semi-coherent metal/ceramic interfaces involving Cu, Ti and N. A genetic algorithm was used to fit the model parameters to the physical properties of the materials. To accurately describe interfacial interactions and shear, two-dimensional generalized stacking fault energy profiles for relevant slip systems were selected as one of the major parameterization targets for the models. The models were applied to study semi-coherent Ti(0001)/TiN(111) and Cu(111)/TiN(111) systems. Ti/TiN was stable with misfits accommodated away from the interface. Cu/TiN, in contrast, was more stable with misfits at the interface. A spiral pattern in the misfit dislocation networks was observed away from the Cu/TiN interface, similar to the metal/metal (111) semi-coherent interfaces. The theoretical shear strength calculated for Ti/TiN when the misfits were several layers away from the interface and for Cu/TiN with the misfit at the chemical interface, had reasonable agreement with experiment.

Keywords

• 2NN-MEAM
• Metal/ceramic interfaces
• Shear strength
• Semi-coherent interfaces
• Genetic algorithm
• Misfit dislocation networks