Effect of surface finishing on fatigue performance of the surgical implant alloy Ti-6Al-7Nb

The possibilities for improving fatigue behavior of the surgical implant (alpha+beta) alloy Ti-6Al-7Nb are investigated. Microstructural modifications on duplex microstructures including alpha(p)-content and cooling rate from the duplex anneal were performed. Both shot peening and roller-burnishing were then applied, with and without a final grit blasting treatment. Using the appropriate combinations of thermomechanical processing and mechanical surface treatment, significant increases in endurance limit can be achieved while at the same time avoiding iron contamination in the surface and developing a high degree of surface roughness.