Metastable Phase Formed in Immiscible Cu-W Multilayers by Ion Mixing

A new metastable hep phase was observed by ion mixing Cu-W multilayered films with compositions of Cu₇₅W₂₅ and Cu ₈₅W₁₅. In thermodynamic modelling, a Gibbs free-energy diagram was constructed applying Miedema's model, and the calculated results were in good agreement with the experimental observations. Moreover, the restricted kinetic condition involved in ion mixing at far-from-equilibrium is also discussed and a sliding mechanism for growing the hcp phase was proposed and the lattice constants deduced accordingly were in good agreement with the experimental values.