Post-Processing of Wire Arc Additive Manufactured Stainless Steel 316L Bone Staples using Laser Shock Peening: A Mechanical and Antibacterial Study

The paper presents the effect of post-processing with laser shock peening (LSP) on the mechanical and antibacterial properties of wire-arc additive manufactured (WAAM) SS316L bone staples. It is observed that the tensile strength and toughness of the WAAM-built SS316L bone staples improved significantly by LSP treatment, which is essential to their longevity and capacity to function under mechanical stress. The LSP-treated samples showed an enhanced presence of significant alloying elements like molybdenum, nickel, and chromium, which are essential for corrosion resistance, as well as a refined microstructure with fewer surface flaws. Furthermore, the antibacterial research showed that the LSP treatment gives the bone staples improved antibacterial qualities. A significant decrease in bacterial colonization was observed in the LSP-treated samples when compared across different periods (24, 48, and 72 h), suggesting the possibility of lower infection rates in clinical settings. SEM images displayed a reduction in biofilm formation with increasing LSP intensity, suggesting improved bacterial resistance due to surface smoothening and densification from LSP. This shows the effectiveness and significance of WAAM integrated with LSP to enhance the mechanical and antibacterial properties of SS316L bone staples, potentially leading to improved medical implants.