Amélioration de la résistance au fretting de l'alliage Ti6Al4V en environnement cryogénique.

Fretting damage appears in quasi static mechanisms submitted to small amplitude oscillatory motion. It leads to catastrophic failure in many industrial applications due to crack initiation or wear damage depending on the amplitude of displacement. To reduce the damage caused by fretting fatigue increasing use of coatings or surface treatments has been made. In service, the grooves in cryogenic turbopump shafts in Ti6Al4V can be damaged, a Cu-Ni-Si coating has solved the problem. New DLC coatings with interesting tribological properties seem to be attractive for solving industrial problem. This present study seeks to analyse the behaviour of plasma nitrided Ti6Al4V with or without a DLC layer and its effect on crack initiation strength.