Early stages of fatigue damage in aluminium and aluminium alloys

In this paper fatigue damage initiation is considered as both microcrack nucleation from microheterogeneities within fatigued material and microcrack growth over distances corresponding to the size of the microstructure. A brief review of the literature shows that, depending on fatigue conditions and microstructure three different types of nucleation sites exist in aluminium and aluminium alloys : slip bands, grain boundaries and brittle particles. In the last part of this paper tentative to obtain a general view of fatigue damage initiation is made from theoritical considerations taking into account incompatibility problems between matrix and microheterogeities