Direct Laser Deposition-Additive Manufacturing of Ti-15Mo Alloy: Effect of Build Orientation Induced Surface Topography on Corrosion and Bioactivity

In this study, the direct laser deposition-additive manufacturing (DLD-AM) process is employed to fabricate Ti-15Mo biomedical alloy along two build directions. The aim is to analyse the effect of induced surface topography on corrosion and in-vitro bioactivity, motivated towards ultimate reduction in post-fabrication surface modifications. The effect of surface roughness on corrosion resistance is analysed in-vitro in simulated body fluid (SBF) by electrochemical study. Owing to higher surface roughness in the vertical build samples (Ra = 52.70 +/- 11.40 mu m) than the horizontal build samples (Ra = 27.10 +/- 4.17 mu m), upto 75% higher corrosion resistance is found for horizontally built samples. The double passive barrier layer formed in horizontal build higher surface finish samples results in lower corrosion. Further, wettability test confirms that both the build orientations exhibit a hydrophilic surface nature, leading to improved cell attachment. SEM-EDS analysis establishes the in-vitro apatite formation on immersion in SBF, for both build orientation samples. This study leads to understand the role of build orientation induced surface topography for production of minimal post-surface treatment Ti-15Mo bio-implants by the DLD-AM process.