Hertzian fatigue in alumina/zirconia laminated composites

In some engineering applications, ceramic materials are subjected to contact fatigue. In order to improve the resistance of ceramics to contact fatigue, it is proposed to use ceramic laminates with residual stresses at the surface. In this work, the Hertzian contact fatigue of an alumina-alumina/zirconia laminated composite produced by tape casting is studied, both under static loading and cyclic loading, together with a monolithic alumina for comparison purposes. It is shown that the laminate composite presents better resistance to the apparition of surface ring crack, due to the residual stresses of the laminate composite. It is also shown that there is a fatigue effect on both materials under cyclic loading, and not only stress corrosion cracking. A simple relationship between applied load and time to apparition of damage is finally proposed.