Nanoindentation Hardness and Corrosion Studies of Additively Manufactured 316L Stainless Steel

In this article, micro-mechanical properties and corrosion resistance of laser powder bed fusion (L-PBF) processed AM 316L stainless steel parts were jointly investigated for different combinations of processing parameters, following a methodology that could be used in product qualification. Various laser powers were employed for the fabrication of all AM 316L stainless steel parts. Nanoindentation, areal roughness, and electron backscattered diffraction (EBSD) characterization were used to characterize the surface of the AM samples prior to corrosion testing. Open circuit potential (OCP), linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization tests were done to compare additively manufactured laser powder bed fusion (L-PBF) 316L stainless steels with different processing parameters. Overall, it was observed that the AM part having 56.67 J/mm³ VED exhibits the best micro-mechanical characteristics. This sample also had the lowest areal surface roughness and smallest grain size. Consequently, this parameter combination had better corrosion resistance compared to the other AM processed 316L parts. The results are useful in process calibration when fabricating for corrosion-resistance applications and provide insights into the relationship among nano-mechanical, crystallography, and long-term corrosion performance.