Abstract
Ti-6Al-4V alloy was subjected to electric discharge machining (EDM) as a surface treatment process. Several experimental investigations have been undertaken in order to assess whether EDM process is a viable surface treatment technique for application in orthopaedics.
The surface roughness, chemical alterations of surface and osteointegration in vitro have been studied. EDM with relatively high peak currents induced sufficient surface roughness and created carbon enriched surface layer for improved osteointegration.
Tensile properties are not substantially varied by EDM, however EDM has detrimental effect on fatigue endurance. Poor fatigue performance of material after EDM process irrespective of its original microstructure can be attributed to surface microcracks, brittle oxidized surface recast layer, internal tensile stresses and notch sensitivity of titanium alloys.
These detrimental effects can be partly avoided by subsequent heat treatments. Microstructural changes of surface and subsurface layers have been observed by means of scanning electron microscopy.
Fatigue performance is found to be the main limit for potential application of EDM process in orthopedics.