Micro Forged Ti 6Al 4V Surfaces: Effects on Roughness, Wettability, Hardness and Bioactivity for Bone Applications

Titanium and its alloys are among the most widely used metallic implants in orthopedic and dental applications. These alloys establish a favorable biological bond with bone tissue. Surface mechanical treatments are one of the surface modification methods that, by creating a nanostructure and severe plastic deformation, increase surface stresses and improve bioactivity behavior and hardness. In the present study, the improvement of bioactivity behavior and surface properties of titanium alloy through surface mechanical treatment by micro-forging method has been investigated. For this purpose, square samples (10×10 mm with a thickness of 0.75 mm) were subjected to micro-forging treatment (10,000 N force, 10 blows per minute) at different durations from 0 to 3 minutes. Microstructural analysis was performed using scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS). Surface hardness was measured by microhardness testing, and contact angle and roughness tests were conducted. Overall, the results indicated that increasing the micro-forging treatment time led to increased surface roughness and significant improvement in bioactivity behavior. Therefore, the sample treated for 3 minutes (with an affected depth of 350 microns, several-fold increase in surface roughness, 18% increase in surface hardness, and ultimately 88% increase in calcium ions and 92% increase in phosphorus ions, leading to enhanced formation of apatite-like calcium phosphate surface precipitates) is introduced as the optimal sample for further tests for bone tissue engineering applications.