Ion-induced phase transformations in nanostructural TiZrAlN films

(Ti,Zr)1 − xAlxNy thin films (300 nm) with Ti:Zr ratio of ~ 1:1 and Al content in metal sublattice up to x = 0.312 were deposited at Ts = 270 °C using reactive unbalanced magnetron co-sputtering in Ar + N2 plasma discharges. The nitrogen content, y, was understoichiometric when x ≥ 0.102, despite constancy of N2 partial pressure used during growth. The influence of Xe ion irradiation (180 keV, 1 × 1015 − 1 × 1017 cm− 2) on the structure, phase formation and mechanical properties of the films was investigated. The increase in Al content resulted in gradual evolution of the microstructure from single-phase, nanocrystalline cubic (c) solid solution (x ≤ 0.072) to dual-phase nanocomposite (x = 0.102–0.200) and then to amorphous (x = 0.312) one. Nanocrystalline and amorphous films were stable under irradiation, while crystallization occurred in nanocomposite films for a typical ion fluence of 1 × 1016 cm− 2. This phase transformation is associated with the reduction of compressive stress and eventually leads to the development of a net tensile stress inside crystallites. For all films, a decrease of the nanoindentation hardness was observed after an ion fluence of 5 × 1016 cm− 2, likely related to the incorporation of Xe impurities, as revealed by RBS data.