Experimental and finite element simulation studies of the bio-tribological behavior of L-PBF Ti-6Al-4V alloys with various surface roughness

Recently, 3D-printed Ti-6Al-4 V alloys have been gradually used for medical implants, where surface quality plays a crucial role in bio-tribological resistance. In this study, we designed three Ti-6Al-4 V samples through mechanical grinding, polishing, and sandblasting to explore the effect of surface roughness on the bio-tribological behavior against the Si₃N₄ counter-ball in a simulated body fluid (SBF) solution. Results indicate an increasing trend in the bio-tribological properties with decreasing surface roughness, with the polished sample exhibiting the lowest wear rate (2.73 × 10⁻³ mm³/N·m) and superior bio-tribological resistance. Finite element simulation reveals that asperities on the rougher surface sample lead to stress concentration, forming larger asperity fragments, enhancing mechanical interlocking and thus intensifying wear. Additionally, with increasing surface roughness, the wear mechanism of the as-printed Ti-6Al-4 V alloy shifts from abrasive and adhesive wear to a combination of abrasive, adhesive, and oxidative wear. This study provides valuable insights into the effect of surface roughness on the bio-tribological properties of as-printed Ti-6Al-4 V alloys, offering guidance for regulating surface quality in biomedical implants.