SPECIAL ISSUE ARTICLE Corrosion resistance in chloride solution of the AlSi10Mg alloy obtained by means of LPBF Marina Cabrini 1,2 | Sergio Lorenzi 1,2 | Tommaso Pastore 1,2 | Cristian Testa 1 | Diego Manfredi 3 | Giulio Cattano 3 | Flaviana Calignano 4 1 Department of Engineering and Applied Sciences, University of Bergamo, Bergamo, Italy 2 INSTM Unità di Ricerca Bergamo, Dalmine, 24044, Italy 3 Center for Sustainable Future Technologies CSFT@PoliTo, Istituto Italiano di Tecnologia‐ IIT, Torino, Italy 4 Department of Management and Production Engineering (DIGEP), Politecnico di Torino, Torino, Italy Correspondence Cristian Testa, University of Bergamo, Department of Engineering and Applied Sciences Viale Marconi 5, Dalmine (BG) 24044, Italy. Email: cristian.testa@unibg.it The paper deals with the corrosion resistance in chloride solutions of an AlSi10Mg alloy obtained by laser powder bed fusion (LPBF) process. The potentiodynamic tests were carried out in solutions having different chloride contents. The results empha- size the role of chloride concentration on localized corrosion. The increase of concen- tration reduces pitting potential. In addition, the influence of the post‐processing heat treatment temperature was recognized. Penetrating attacks occurred either on after low temperatures stress relieving or specimens without any treatment, promoted by selective dissolution of the α‐Al phase stimulated by galvanic coupling with noble sil- icon precipitates at the border of the melt pool. Such penetrating morphology was not observed after heat treatments at high temperature. KEYWORDS additive manufacturing, Aluminium alloy, heat treatment, laser powders bed fusion, pitting potential 1 | INTRODUCTION Laser Powder Bed Fusion (LPBF) is an additive manufacturing technique for fusion of metal powders, layer‐by‐layer, by using a laser moving in accordance with the 3D CAD model. 1 This production method has advantages in terms of cost reduction and manufacturing time. It eliminates the swarf typical of traditional subtractive machining and permits to obtain new complex forms. 2 The manufacture of aluminium components by this technique requires a careful laser scanning strategy to avoid the formation of oxide at the interface between adjacent traces and to limit the porosity. 3 The LPBF machine should be equipped with an inert atmosphere room, being the reactive nature of the metal. Nowadays, the hypoeutectic AlSi10Mg alloy is considered the best aluminium alloy for this technique, allowing to achieve high‐density and good mechanical properties. 4-6 It is relatively easy to process by laser appli- cations because its composition lead to a narrow solidification range. A small addition of magnesium (0.3–0.5 wt%Mg) is able to induce precipitation hardening by forming dispersed Mg 2 Si phase during nat- ural or artificial ageing. In addition, the alloy shows adequate corrosion resistance in mild environments and atmospheric exposure, because of the natural ability to form a stable and adherent passive oxide layer. Thanks to very fast cooling compared with traditional casting, LPBF process gives very fine microstructures having high mechanical properties, 7,8 but the components made with this innovative process have rough surfaces affecting the corrosion resistance. Previous works demonstrate that surface treatments as polishing and shot penning enhance corrosion resistance of surfaces as produced by manufactur- ing. Furthermore, selective attacks were observed at the border of the melt pools, caused by the galvanic corrosion promoted by the inhomo- geneous precipitation of cathodic silicon particles. 9-15 The aim of work is the study of localized corrosion resistance of an AlSi10Mg alloy obtained by means of LPBF. The behaviour was evaluated in chloride solutions, by measuring the pitting potential (E pit ) as a function of chloride ion activity. The effect of post‐processing heat treatments at 200°C, 300°C, and 400°C for 2 h was also studied. Received: 14 September 2018 Accepted: 22 November 2018 DOI: 10.1002/sia.6601 Surf Interface Anal. 2018;1–6. © 2018 John Wiley & Sons, Ltd. wileyonlinelibrary.com/journal/sia 1