Enhanced surface properties and bioactivity of additively manufactured 316L stainless steel using different post-treatments

It is well documented that the surface characteristics of each component play a key role in its performance. In particular, in the case of Metal Additive Manufacturing (MAM) processes, surface quality is one of the key challenges in the production of metallic components. Therefore, this work investigates the influence of two post surface treatments on surface features such as surface roughness, microhardness, wettability and bioactivity of the AISI 316 L stainless steel alloys produced by the laser powder bed fusion technique. The as-built samples were subjected to two different post-treatments of laser polishing and shot peening. The outcomes indicate that the shot peening process resulted in lower surface roughness and higher surface hardness compared to the as-built state. The X-ray diffraction results indicated that there was no considerable phase change after the post-treatments. The in vitro bioactivity analysis reveals the increment in apatite formation due to better wettability and high surface energy for treated samples. It is concluded that post surface treatment of the AISI 316L samples can improve their surface properties and their bioactivity behaviour, making them promising candidates for orthopaedic implants.