This study investigated the correlation between the MnS·xMnO·yAl2O3·zSiO2·TiN complex inclusions and localized corrosion initiation of the wire arc additively manufactured (WAAMed) super duplex stainless steel (SDSS) part. The results showed that partial dissolution of crystalline MnS within the complex inclusions generated an acidic aggressive environment to led the dissolution of amorphous oxides part, thereby triggering the process of localized corrosion. Additionally, micro-crevices between the inclusions and metallic matrix exacerbated localized corrosion. Finally, the catalytic-occluded cells accelerated propagation of pits. Hence, formation of high density of inclusions resulted in the poor localized corrosion resistance and repassivation ability of the as-built WAAMed SDSS.
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