Improvement of the fretting damage resistance of Ti-811 alloy by Cu/Ni multilayer films

►We prepare the Cu/Ni multilayer films by ion-assisted deposition technique. ►Superhardness is observed for a modulation period of <200 nm. ►Fretting fatigue resistance of the titanium alloy is improved by the Cu/Ni films. ►The resistance does not increase monotonically with the modulation period. ►Films with a modulation period of 200 nm had the highest resistance.