On microstructure and corrosion behaviour of AlSi10Mg alloy with low surface roughness fabricated by direct metal laser sintering

In this study, in-depth microstructure and electrochemical properties of highly smoothed AlSi10Mg parts fabricated through direct-metal-laser-sintering are reported. The samples with the lowest surface roughness were characterized by having a periodic large and small melt pools (MPs) pattern in their upskin layers. Consequently, a noticeably coarser eutectic-Si network, Al-dendrite and grain size formed along the larger MPs' borders, rationalized by their slower solidification rate. Such microstructural features were found to control/deteriorate the electrochemical performance of the as-printed samples than their surface roughness. An improved electrochemical stability for the samples that experience the fastest solidification rate along their MP-boundaries was revealed.