EARLY STAGES OF FATIGUE DAMAGE IN ALUMINUM AND ALUMINUM-ALLOYS

In this paper fatigue damage initiation is considered as both microcra ck nucleation from microheterogeneities within fatigued material and m icrocrack growth over distances corresponding to the size of the micro structure. A brief review of the literature shows that, depending on f atigue conditions and microstructure three different types of nucleati on sites exist in aluminium and aluminium alloys:slip bands, grain bou ndaries and brittle particles. In the last part of this paper tentativ e to obtain a general view of fatigue damage initiation is made from t heoritical considerations taking into account incompatibility problems between matrix and microheterogeities.