Effect of Laser Welding on In-Vitro Bioactivity Properties of Ti6Al4V Joints

Abstract

In this study, the Ti6AI4V alloy, which is used as an implant material in the medical field, was joined with the laser welding method at different welding speeds. The bioactivity features of the Ti6AI4V alloy and its samples joined at different welding speeds were determined by immersing in a simulated body fluid (SBF) for 1, 7, 14, 21 and 28 days. The hydroxyapatite (HA) formation on the surfaces of the samples was determined by calculating the weight gain. The weight loss was calculated by removing the HA from the surface after bioactivity testing. The corrosion rates of the samples were also determined according to the weight loss. In addition, the characterization of the HA formed on the surfaces of the samples was performed. As a result of the investigations, it was determined that the increase in laser welding speed, and therefore the decrease in heat input, positively affected the bioactivity and biocorrosion features of the Ti6Al4V laser welded joints. It was determined that the particle sizes of the HAs of the laser weldments increased with lower heat inputs. It was also observed that the amount of HA nucleated on the laser-welded samples increased in accordance with the increase in the laser welding speed. The laser welded samples that were welded at higher welding speeds and therefore at lower heat inputs, exhibited better biocorrosion behaviors.