Evaluation of fretting corrosion fatigue in burnishing of Ti6Al4V component for artificial hip joint

Modular hip replacements provide a flexible way to reconstruct the joint with optimized biomechanics, but one of the most common causes of modular hip prostheses failure is the fretting corrosion at the neck-head interface combined with their related micro-motion. In this context, the present study aims to improve the neck surface strength by means of burnishing process. An experimental campaign on Ti6Al4V hip joint neck was carried out at varying burnishing parameters: force and speed. The main surface integrity parameters affecting the neck performance have been evaluated, namely mean surface roughness, micro hardness, affected layer and microstructure. Afterwards, fretting corrosion fatigue tests on necks and alumina ceramic heads were performed under standard conditions simulating human walking. The relative motions at the neck-head interface were analyzed by an innovative technique able to detect changes during the test with high accuracy.