Abstract
In our previous study, it was found that the wear life of the DLC/AlN hybrid film compared with a DLC film deposited directly onto Al-alloy could be improved by controlling the hardness of the AlN intermediate layer film．However, the hard coating like above films has a possibility to decline the fatigue strength of based material. In the present study, to ensure the fatigue reliability of Al alloy coated with DLC/AlN hardness gradient hybrid film, the fatigue strength and the fatigue failure mechanism were investigated. Fatigue strength of A7075 alloy coated with DLC/AlN hybrid film in lower stress side was higher than the untreated material, but that in higher stress side was almost the same as the untreated material.
