Hydrogen embrittlement of super duplex stainless steel – Towards understanding the effects of microstructure and strain

The hydrogen embrittlement sensitivity of duplex stainless steel with different phase fractions evaluated by in-situ mechanical testing

“…This is in agreement with other findings in literature since ferrite is considered more susceptible to hydrogen embrittlement than austenite [18,[26][27][28]. Moreover, Örnek et al [29] found that DSS microstructures with a large austenite spacing were more sensitive to HE. The spacing of the austenite ribbons was larger in the HT 1990 sample, both on account of it having a lower austenite fraction and a slightly larger grain size, as mentioned in the previous section and as seen in Fig.…”

Passive film characterisation of duplex stainless steel using scanning Kelvin probe force microscopy in combination with electrochemical measurements

“…The naturally formed passive film over the ferrite is different than that of the austenite, giving rise to a typical Volta potential difference of 40-70 mV of numerous DSS's. 12,13,19,25 Laurent et al 24 reported a chromium-rich oxide, in the form of chromia, that became further enriched in the passive film upon passivation in nitric acid, with the thickness, however, not been majorly altered. This may explain the reason why the Volta potential of ferrite and austenite of the DSS were similar after immersion in nitric acid.…”

“…Hydrogen can migrate rapidly into metals, and the ferrite can absorb more hydrogen per time than austenite due to higher diffusivities, 34,35 causing strain localisation in the DSS microstructure. 25 The solubility of hydrogen, however, is typically two orders of magnitude higher in the austenite than in the ferrite due to its closed-packed structure, but the austenite can accommodate more lattice strain due to its face-centre-cubic structure. 36,37 Hydrogen diffusion into austenite is retarded and requires more energy, but once hydrogen has infused the effusion rate will be significantly slower than that of the ferrite.…”

Toward Understanding the Effects of Strain and Chloride Deposition Density on Atmospheric Chloride-Induced Stress Corrosion Cracking of Type 304 Austenitic Stainless Steel Under MgCl2 and FeCl3:MgCl2 Droplets

“…54,67,75,88 Pits can further nucleate preferentially on regions containing high strain and facilitate early breakdown of passive film. 6,[63][64][65][89][90][91] Hydrogen, formed during corrosion reactions, can enhance the pitting susceptibility by lowering the electrochemical nobility in local scale due to trapped hydrogen and perturbed the passive surface oxide film, facilitating early breakdown. 6,[63][64][65][89][90][91] Pit initiation in commercial austenitic stainless steels, hence, is rather deterministic due to multiple sites present in the microstructures.…”