Metastable cellular structures govern localized corrosion damage development in additive manufactured stainless steel

Evan DelVecchio, Tiffany Liu, Yen-Ting Chang, Yuheng Nie, Maryam Eslami, Marie-Agathe Charpagne

Research output: Contribution to journalArticlepeer-review

Abstract

The rapid solidification associated with additive manufacturing (AM) leads to complex microstructures with peculiar features amongst which cellular solidification structures are the most remarkable. These metastable structures possess a clear segregation pattern dictated by the solidification pathway of the alloy and are bounded by dislocation walls. While they confer exceptional strength and ductility to AM 316L stainless steel, their effect on localized corrosion in chloride environments remains to be established. Here, we employ correlative electron microscopy to reveal coupled chemical, electrochemical, and crystallographic effects on localized corrosion attack and its development. We show that the Cr and Mo-depleted interior of the cellular solidification structures dissolves selectively, giving rise to an intricate damage morphology, that is directly related to the underlying crystallographic orientation. Whereas surface observations only reveal apparently shallow micrometer-size cavities, 3D tomography via focused ion beam serial-sectioning shows a high degree of connectivity between these features underneath the surface. We reveal this intricate morphology, propose a formation mechanism, and discuss alloy design guidelines to mitigate this phenomenon.
Original languageEnglish (US)
Article number45
Journalnpj Materials Degradation
Volume8
Issue number1
DOIs
StatePublished - Apr 30 2024

Fingerprint

Dive into the research topics of 'Metastable cellular structures govern localized corrosion damage development in additive manufactured stainless steel'. Together they form a unique fingerprint.

Cite this