Development of Ti/Ti-DLC multilayers on magnesium alloys. Part 1: Microstructure and mechanical properties

To improve both the corrosion resistance and wear resistance of magnesium alloys, titanium-diamond-like carbon (Ti-DLC) monolayer and Ti/Ti-DLC multilayer films with two periods were applied to AZ31 magnesium alloys through filter cathodic vacuum arc deposition technology. The Ti-DLC monolayer film exhibited an amorphous structure doped with TiC nanocrystals. After introducing the Ti sublayer, the Ti/Ti-DLC multilayer films exhibited a layered structure, resulting in improved adhesion strength and fracture toughness and lower hardness. Compared with the (Ti/Ti-DLC)4 multilayer film with a smaller period, the (Ti/Ti-DLC)2 multilayer film with a lager period exhibited better adhesion strength, higher fracture toughness, hardness, ID/IG ratio, and lower residual stress owing to its thicker Ti sublayers.