Biocompatibility and Mechanical Behaviour Studies on Wire-Arc Additive Manufactured Stainless Steel 316L and Shape Memory Alloy (NiTi) Materials for Biomedical Implants

Abstract Stainless steel 316L (SS316L) and Nickel-titanium alloy (NiTi), which are additively manufactured metallic biomaterials, are explore for their biocompatibility and mechanical properties in bio-implant applications. The nickel-titanium alloy (NiTi) has been suggested for exceptional thermal shape memory, super elasticity, and high damping qualities compared to Stainless steel 316L (SS316L). In this present study, the input process variables such as voltage, wire-feed rate, dwell time and argon gas flow rate have been maintained constantly (fixed) based on the trial experiments. The metallic biomaterials (Stainless steel 316L (SS316L) and Nickel-titanium alloy (NiTi)) are fabricated using a wire-arc additive manufacturing process and it is utilized to study the mechanical properties such as tensile, yield strength and % elongation. The additive manufactured biomaterials such as Stainless steel 316L (SS316L) and Nickel-titanium alloy (NiTi) have been compared and studied the impact of biocompatibility (Cytotoxicity) and anti-bacterial property for surgical implant applications. From the result, it has been found that the shape memory alloy (NiTi) has higher ultimate tensile and yield strength than the Stainless steel 316L (SS316L) due to its high corrosion resistance, super elasticity, and shape memory behaviour. In addition, the cytotoxic effects of both biomaterials (SS 316L and NiTi alloy) on L929 mouse fibroblast cells were examined in the cell culture media. The biocompatibility and anti-bacterial characteristics of SS 316L and NiTi alloy has been investigated, which would support its use as a surgical implant.