Ion irradiation induced solid-state amorphous reaction in Ni/Ti multilayers

► 180 keV Ar was implanted to 1-6 × 1016 ions/cm2 in (Ni 26 nm/Ti 20 nm) × 5 multilayers. ► The intermixed phase is fully amorphous, starting from the initial stages. ► Continuous ∼127 nm amorphous Ni66Ti34 layer is formed at high irradiation dose. ► The amorphous phase is not affected by further increase of the ion dose. ► The results can be interesting for studies of radiation tolerance of am-NiTi.