Inter-melt pool corrosion and repassivation of SS316L stainless steel processed by laser powder bed fusion

Hariharan, Karthikeyan; Guo, Xiaolei; Huang, Hsien-Lien; Sridhar, Narasi; Srinivasan, Jayendran; Hwang, Jinwoo; Frankel, Gerald S.; Schindelholz, Eric J.

doi:10.1016/j.corsci.2023.111668

Cited by 5 publications

(2 citation statements)

References 34 publications

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“…10b–d ). This preferential attack is analogous to intergranular corrosion of regions depleted of Cr/Mo 16 , 18 . However, at 125 °C a more severe attack was observed where the pits were wider by a whole order of magnitude with them ranging from 50 μm to 3 mm (Fig.…”

Section: Resultsmentioning

confidence: 95%

“…The formation of dislocation networks at the cell boundaries and the enrichment of Cr/Mo at these regions have been reported by several works 5 , 12 – 17 , leading to a competing effect on whether the cell interiors or boundaries become the preferred site of localized attack. There is however a discrepancy regarding which microstructural features were more susceptible to attack, with different studies reporting these to be the melt-pool boundaries (MPBs) 8 , 16 , 18 , cell boundaries 12 , 19 , inclusions 12 , 20 as well as cell interiors 15 , 17 . Most of the studies performed showed corroded surfaces or pits formed when higher potentials were applied to accelerate the film breakdown and localized corrosion.…”

Section: Introductionmentioning

confidence: 99%

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Localized corrosion in selective laser melted SS316L in CO2 and H2S brines at elevated temperatures

Narayanan,

Martinez,

Martin

et al. 2024

npj Mater Degrad

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In this work, the passivation and localized corrosion of selective laser melted (SLM) stainless steel 316 L when exposed to high pressures of CO2 with the presence of H2S and Cl− at 25 °C and 125 °C were studied. Depletion of Cr/Mo was observed at the cell interiors and melt-pool boundaries (MPBs) compared to the cell boundaries. Volta potential differences obtained from scanning Kelvin probe force microscopy (SKPFM) showed that the MPBs were 8–20 mV lower than the matrix, while the cell interiors were 20–50 mV lower than the cell boundaries. Electrochemical impedance spectroscopy (EIS) and Mott–Schottky tests indicated a more defective passive film at 125 °C, and X-ray photoelectron spectroscopy (XPS) confirmed the formation of a less protective film with an increased S/O ratio at 125 °C than 25 °C. Initiation of localized corrosion was observed at the MPBs and pits formed after a week of immersion were wider by an order of magnitude at 125 °C than 25 °C, with evidence of cell-interior dissolution. While passivity was observed even at elevated temperatures, local chemical heterogeneities compromised the stability of the film and contributed to localized corrosion in SLM SS316L.

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Section: Resultsmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Localized corrosion in selective laser melted SS316L in CO2 and H2S brines at elevated temperatures

Narayanan,

Martinez,

Martin

et al. 2024

npj Mater Degrad

View full text Add to dashboard Cite

show abstract

Prediction of Hydrogen Diffusion Behavior under the Influence of Defect Structures in Stainless Steel Passivation Film Based on Molecular Dynamics

Liu,

Qiu,

Chen

et al. 2024

ACS Omega

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The excellent corrosion resistance of stainless steel primarily relies on the formation of a dense passivation film on its surface. Stress corrosion and hydrogen embrittlement are the primary forms of damage to the stainless steel passivation film, leading to film rupture and subsequent corrosion of the stainless steel substrate. The passivation film exhibits semiconducting properties and typically consists of a bilayer structure with a chromium-rich inner layer and an iron-rich outer layer. This study employs molecular dynamics simulations to investigate the interaction energy between hydrogen atoms and pristine stainless steel passivation films (Fe 2 O 3 /Cr 2 O 3 ) as well as those containing three different types of defects and predicts the diffusion processes of hydrogen atoms in passivation films. The results indicate that the strongest interaction energy of −1.4402 eV is observed between hydrogen atoms and the pristine passivation film. However, as defects emerge within the passivation film, the interaction energy decreases, with a minimum energy of −0.1931 eV observed for the film containing chromium vacancies (V Cr ), representing a nearly one-order-ofmagnitude reduction compared to the defect-free case. Furthermore, the diffusion coefficients of hydrogen atoms in the three defective passivation films are calculated as 6.437 × 10 −10 , 8.249 × 10 −10 , and 50.892 × 10 −10 m 2 /s, respectively. Notably, the presence of a V Cr defect enhances the hydrogen diffusion coefficient by an order of magnitude compared to the pristine film. Anisotropic diffusion paths and properties are elucidated through an analysis of the self-diffusion behavior of hydrogen in different detective passivation films, providing a theoretical basis for the prediction of hydrogen-induced cracking and the development of early warning technologies for passivation film surface failure.

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Microstructure engineering for corrosion resistance in structural alloy design

Hariharan,

Virtanen

2024

npj Mater Degrad

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During structural alloy development, the initial microstructure design is mainly considered in the context of achieving a balance of mechanical properties, with corrosion resistance often considered much later in the process. This perspective uses illustrations from degradation mechanisms in 3D-printed alloys and in-service microstructure evolution-driven mechanisms to show the importance of microstructure design for corrosion resistance and mechanical properties simultaneously, to improve the reliability of critical infrastructure.

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Inter-melt pool corrosion and repassivation of SS316L stainless steel processed by laser powder bed fusion

Cited by 5 publications

References 34 publications

Localized corrosion in selective laser melted SS316L in CO2 and H2S brines at elevated temperatures

Localized corrosion in selective laser melted SS316L in CO2 and H2S brines at elevated temperatures

Prediction of Hydrogen Diffusion Behavior under the Influence of Defect Structures in Stainless Steel Passivation Film Based on Molecular Dynamics

Microstructure engineering for corrosion resistance in structural alloy design

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