Microstructure-induced anisotropic biocorrosion response of laser additive manufactured WE43 alloy

The microstructure and corrosion of laser-processed WE43 was studied. Results suggest that multi-factors like grain structure, crystallographic defect, and precipitate distribution result in an anisotropic corrosion response. XY plane with high crystal defect densities offers more sites for pitting corrosion. Filiform corrosion is detected on both XY plane and XZ plane, where Zr-rich and RE-rich precipitate distribution plays an essential role in corrosion initiation and propagation. The enrichment of Zr around filament corrosion promotes local micro-galvanic corrosion. Notably, the XY-plane, with continuous distribution and extended scanning trajectory edge, is particularly susceptible to filiform corrosion as compared with XZ-plane. •XY-plane presents a bimodal structure, while XZ-plane consists of coarse grains.•Corrosion preferably occurs at molten pool boundaries with high dislocation.•Zr-rich participates induced filiform corrosion on both XY- and XZ- plane.•Different texture and precipitate distribution cause anisotropic corrosion response.