As the thickness of a thin film is decreased, the interfacial structure becomes paramount and crystals can undergo phase transformations. Molecular dynamic simulations have been performed to capture how such transformation could occur under the growth surface of a film. An hcp to bcc transition in Ti for Ti/Nb multilayers was used as the case studies. The simulations had good agreement with experiments. The simulations further predicted a mixed phase state for Ti for particular equal layer thicknesses.