Nitriding aluminum alloys by N-multicharged ions implantation: Correlation between surface strengthening and microstructure modifications

► Surface strengthening of Al alloys by multi-charged ion implantation was studied. ► Microstructure evolution was studied by XPS analysis, GIXRD patterns and AFM. ► Mechanical properties were analyzed by nanoindentation and tribological experiments. ► Hardening was attributed to AlONγ and AlN and to precipitation-induced-stress. ► The relaxation of the implanted layer is mandatory for a good wear resistance.