Fretting fatigue behaviour of Ti–6Al–4V in contact with Alloy 718

Abstract

In studies on a material fretted with different contact pad materials having different hardness values, there will be effect of both chemical composition and hardness. In the present work, the effect of hardness was studied by keeping the chemical composition of the contact pad material the same. Test samples were made of Ti–6Al–4V and fretting pads were made of Alloy 718. By heat treatments (annealing and ageing), the hardness of the pads was changed. The effect of hardness of pads was observed only at higher contact pressure of 175 MPa and lower cyclic stresses, where annealed pads restricted the life of Ti–6Al–4V samples compared to aged pads. This is because the relatively softer Alloy 718 pads in annealed condition had relatively higher adhesion to the Ti–6Al–4V samples leading to higher tangential force coefficient values compared to that of harder pads in the aged condition.