Ion beam induced formation of metastable alloy phases in Cu–Mo system during ion beam assisted deposition

The Cu–Mo alloy film with positive heat of mixing was prepared by ion beam assisted deposition (IBAD) technique. When the energy of Ar+ ions was 2 keV during IBAD, metastable bcc Cu was formed in the Cu20Mo80 film. A Mo-based bcc supersaturated solid solution was obtained within the composition range of 0–50% Cu fraction. An fcc supersaturated solid solution was also formed around the composition of 15 at.% Mo. The formation mechanisms of the metastable alloy phases were discussed in terms of the process far from equilibrium.