Microstructure and corrosion evaluation of as-built and heat-treated 316L stainless steel manufactured by laser powder bed fusion

In this study, the effect of as-built and heat-treated additively manufactured 316L stainless steel at different temperatures was examined on the electrochemical corrosion performance. The corrosion was investigated by Tafel polarization and electrochemical impedance spectroscopy methods in a 3.5% NaCl solution. For this purpose, the as-built and heattreated printed samples were examined via optical and Field Emission Scanning Electron microscopy. Energy Dispersive X-Ray Spectroscopy analysis was used for the elemental mapping for all samples. Vickers microhardness was measured to assess the sample grain structure response and for measurement of phase change, X-ray diffraction was used. Microstructural analysis results confirmed an austenite phase prior to 900 degrees C. For the heattreated sample at 900 degrees C and 1000 degrees C, the ferrite phase appeared in the austenite field and a fully austenitic structure was obtained at 1100 degrees C. The microhardness results indicated how the surface hardness decreased at a higher heat treatment temperature. From the corrosion tests, the higher heat-treatment temperatures resulted in better resistance to corrosion due to the larger grain size, uniformity of metallurgical structure, and lattice structure stress relief. (c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

The study examined the effect of as-built and heat-treated additively manufactured 316L stainless steel at different temperatures on electrochemical corrosion performance, showing that higher heat-treatment temperatures resulted in better resistance to corrosion.