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

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. (c) 2020 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).