Influence of heat treatments on the corrosion mechanism of additive manufactured AlSi10Mg

•Heat treatments progressively destroy the initially continuous silicon network.•The corrosion mechanism changes when the silicon network becomes discontinuous.•Melt pool borders play a key role in the corrosion mechanism. This study focuses on the effect of heat treatments on the microstructure and corrosion behaviour of additive manufactured AlSi10Mg specimens. Non heat treated, artificially aged and stress released specimens were studied. The microstructure showed an evolution from cellular aluminium cells surrounded by a 3D network of fibrous eutectic silicon phase to coarse separated silicon particles. The corrosion behaviour was found to change with the heat treatments. Untreated and artificially aged specimens showed superficial corrosion attacks with microcrack formation while stress released specimens showed penetrating attacks without microcrack formation. Mechanisms were proposed for the microstructure evolution and the different corrosion behaviours.