Post-Processing of AM-EBM Ti6Al4V for Biomedical Applications: Evolution of Mechanical Properties as a Function of Surface Roughness

Post-processing, and particularly the dry electropolishing process, is essential for improving the surface quality of 3D-printed Ti6Al4V samples, with specific emphasis on reducing roughness over extended polishing times while preserving mechanical properties. Reducing surface roughness enhances the reliability of hardness measurements and improves the consistency of elastic modulus measurements, as prolonged polishing time stabilizes the full width at half maximum values, thereby minimizing variability due to uniaxial indentation. This stability is crucial for maintaining the structural integrity and uniformity of mechanical properties, facilitating better performance and reliability in biomedical applications. Additionally, under service-like working conditions, solid electrolyte particles undergo dehydration due to the Joule effect, introducing a dynamic aspect to the system as the particle structure degrades with thermal cycling. EDX cross-sectional analysis reveals that TiO2 informs the particle's surface, with an oxygen-to-titanium ratio that confirms the oxide's composition. This TiO2 oxide layer demonstrates the progressive surface oxidation occurring under the post-processing process, further modifying the particle's surface chemistry. This dual effect of roughness reduction and controlled surface chemistry highlights the role of dry electropolishing in enhancing the functional lifespan and mechanical reliability of Ti6Al4V components.