Additively manufactured 316L stainless steel as a potential alternative implant material

Abstract

The microstructural features, electrochemical corrosion behavior, and biocompatibility with Locke's solution were evaluated for 316L stainless steel (SS) samples fabricated by selective laser melting (SLM) with understudied processing conditions providing low residual stress - 800, 1000 and 1200 mm/s laser scan speed with a laser power of 100 W. Confocal images and scanning electron microscopy found fewer SLM processing induced surface flaws at samples fabricated at 800 mm/s. Electrochemical impedance spectroscopy and potentiodynamic polarization measurements indicated samples fabricated at 800 mm/s developed a more compact and thicker passive oxide film resulting in greater corrosion resistance, relative to samples prepared at the higher laser scan speeds. The surface characteristics of SLM 316L SS samples fabricated at 800 mm/s also promoted substantial biocompatibility that was observed via cell attachment and differentiation of osteoblasts, as well as high collagen 1A coverage indicating strong potential as a alternative implant material.

Keywords

• Electrochemical corrosion behavior
• SLM 316L SS
• Passive oxide layer
• Biocompatibility
• Microstructural differentiation
• Osteoblasts