Insight into the passivation and corrosion behavior of additive manufacturing repaired single crystal superalloy

The passivation and corrosion behaviors of additive manufacturing repaired Ni-based single crystal superalloy were analyzed by comparison with the substrate. We found that the cladding layer is comprised of fine cellular dendrites (FDs) and fine cellular interdendritic zones (FIDZs) with abundant nano particles of gamma & PRIME;(Ni3Al) phase. The cladding layer possesses thicker passive film which gives better protection to the cladded component. The FIDZs are more sensitive to corrosion because of the dissolution of Nb-rich and Cr-Mo depleted zones in FIDZs. The gamma/gamma & PRIME; couples in the substrate tend to form mesh-like corrosion morphologies due to the selective dissolution of gamma & PRIME; phases.

Automated summary

The passivation and corrosion behaviors of additive manufacturing repaired Ni-based single crystal superalloy were analyzed, revealing that the cladding layer has a thicker passive film providing better protection, while the interdendritic zones are more susceptible to corrosion.