Fretting fatigue is one of the most detrimental loadings for crack nuc
leation. Aeronautical aluminium alloys have been analysed during the f
irst cycles of fretting so to determine the evolution of the maximum t
angential force and the coefficient of friction. Several stages have b
een identified as velocity accommodation takes place in the superficia
l oxide layers, in the two first bodies or in the third body (debris b
ed). The effects of the test frequency or of the surface roughness wer
e shown to depend on these stages. The effect of the brittleness of th
e first body has been analysed by means of the comparison between AI-L
I and Al-Si alloys. The latter brittle alloy better resisted crack nuc
leation despite its lower fatigue strength. This could be related to t
he early detachment of debris in the fretting contact. Copyright (C) 1
996 Elsevier Science Ltd