Abnormal corrosion behavior of selective laser melted AlSi10Mg alloy induced by heat treatment at 300 °C

Heat treatment is often employed to control the mechanical properties of selective laser melted (SLMed) AlSi10Mg, which also alters its microstructure and corrosion resistance. Therefore, a SLMed AlSi10Mg alloy was heat treated at 300 °C and 400 °C for 2 h to investigate its microstructural evolution and corrosion behavior. Abnormal corrosion behavior is observed in the sample heat treated at 300 °C. Heat treatment destroys the cellular Si network in the microstructure of the SLMed AlSi10Mg sample and promotes the formation of extremely fine Si particles; in contrast, such a microstructure cannot form a protective film on the surface of the sample, which leads to rapid corrosion along the cracked Si network inward to the inner Al matrix without the microgalvanic effect.