Surface changes and fretting fatigue evaluation of Ti6Al4V burnished hip necks

This study investigates the surface changes and fretting phenomena at neck-head interface of Ti6Al4V alloy. In particular, hip necks subjected to burnishing process are the objective of the experimental campaign. Ti6Al4V is a widely used material in orthopedic implants due to its excellent biocompatibility and mechanical properties. However, the potential for fretting fatigue is a common concern in hip implants requiring the exploitation of surface modification techniques to enhance the implant’s performance and durability. Burnishing process involves the controlled application of mechanical pressure to the implant’s surface, which can generate residual stresses and changes in surface topography. By employing advanced surface characterization techniques, including micrograph and profilometry, the surface modifications induced by burnishing were evaluated. Furthermore, fretting fatigue assessment was carried out through mechanical testing, simulating the conditions encountered in the hip joint during typical daily activities. Finally, an emerging sensing technology in the field of non-destructing optical testing, phase-based motion estimation (PBME) was employed in order to assess the surface gradual degradation before failure.