Influence of microstructure on the anisotropic tribocorrosion behaviour of WAAM-fabricated SS304L in marine environments

Abstract

This study examines the anisotropic tribocorrosion behaviour of WAAM-fabricated 304 L stainless steel in simulated marine environments, testing three orientations: top, side, and front. The top orientation demonstrated superior corrosion resistance with the low I_corr (25.32 µA/cm²) and corrosion rate (97.73 µmpy), making it suitable for corrosion-critical applications. Microstructural analysis revealed significant anisotropy, with variations in ferrite content and morphology across orientations, and the top orientation exhibiting the lowest ferrite percentage, confirmed through image analysis and XRD. The anisotropic properties were linked to microstructural heterogeneities from the WAAM process. WAAM samples exhibited better tribocorrosion resistance than wrought 304 L, but their anisotropic properties require careful orientation-specific design and evaluation for marine applications.