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Molecular dynamics studies of helium bubble effects on grain boundary fracture vulnerabilities in an Fe 70 Ni 11 Cr 19 –1%H austenitic stainless steel
Comprehensive molecular dynamics tensile test simulations have been performed to study the delamination processes of seven different grain boundaries / cleavage planes (Σ1{111}, Σ3{111}, Σ5{100}, Σ7{111}, Σ9{411}, Σ11{311}, and R{100}/{411}) containing a helium bubble. Combinations of a variety of conditions are explored including different strain rates, system dimensions, bubble density, bubble radius, bubble pressure, and temperature. We found that in general, grain boundaries absorb less energies with decreasing strain rate but increasing bubble areal density, bubble pressure, bubble radius, and temperature. The propensity of grain boundary delamination is sensitive to grain boundary type: The random grain boundary R{100}/{411} is one of the most brittle boundaries whereas the Σ1{111} cleavage plane and the Σ3{111} twin boundary are two of the toughest boundaries. The sorted list of grain boundary fracture vulnerability obtained from our dynamic tensile test simulations differs from the one obtained from our decohesion energy calculations, confirming the important role of plastic deformation during fracture. Finally, detailed mechanistic analyses are performed to interpret the simulated results.
Enabling molecular dynamics simulations of helium bubble formation in tritium-containing austenitic stainless steels: An Fe-Ni-Cr-H-He potential
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Elucidating the grain-orientation dependent corrosion rates of austenitic stainless steels
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Emergence of micro-galvanic corrosion in plastically deformed austenitic stainless steels
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Role of cavities on deformation-induced martensitic transformation pathways in a laser-welded, neutron irradiated austenitic stainless steel
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Molecular dynamics exploration of helium bubble nucleation and growth mechanisms in Fe 70 Ni 11 Cr 19 austenitic stainless steel
The growth of helium bubbles impacts structural integrity of materials in nuclear applications.
Observations of Atmospheric Corrosion Testing on Heated Austenitic Stainless Steel Surfaces: Exploring the Role of Inert Dust Particulates and Seawater
Relevant atmospheric corrosion laboratory testing environments were developed to explore the influence of inert dust and seawater on the corrosion susceptibility of stainless steel in spent nuclear fuel dry storage conditions. Measurements from dust collected on in-service dry storage canisters were applied to develop exposure conditions. Three atmospheric exposure conditions, two static and one cyclic, were examined with three different surface coverages: co-deposited large dust and seawater, co-deposited small dust and seawater, and solely seawater. Stainless steel coupons representative of spent nuclear fuel dry storage canister material were subjected to the various corrosion environments, with the results from exposures up to 1 year presented here. Post exposure, corrosion damage was analyzed using optical microscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy. Initial observations are presented herein, and potential implications with respect to the influence of inert dust particles on corrosion susceptibility are summarized. In general, the co-deposition of dust and salt resulted in larger pits and exhibited mixed modes of corrosion that were not observed in the no-dust conditions (i.e., crevicing, filiform, and pits within pits). The presence of the inert dust may influence brine spreading and/or act as crevice formers, leading to enhanced corrosion. This study highlights the significance of incorporating dust particulate(s) beyond the deliquescent chemistries to fully evaluate atmospheric corrosion severity.
EVALUATING THE RESISTANCE OF AUSTENITIC STAINLESS STEEL WELDS TO HYDROGEN EMBRITTLEMENT.
Abstract not provided.
Hydrogen Effects on Fatigue Life of Welded Austenitic Stainless Steels Evaluated with Hole-Drilled Tubular Specimens.
Abstract not provided.
EFFECT OF INTERNAL HYDROGEN ON FATIGUE CRACK INITIATION SITES IN 316L AUSTENITIC STAINLESS STEEL.
Abstract not provided.
FATIGUE CRACK INITIATION AND FATIGUE LIFE TESTING OF HIGH-STRENGTH AUSTENITIC STAINLESS STEEL TUBING WITH INTERNAL HYDROGEN
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Influence of Realistic, Cyclic Atmospheric Cycles on the Pitting Corrosion of Austenitic Stainless Steels
Pitting corrosion was evaluated on stainless steels 304H, 304, and 316L the surfaces of which had ASTM seawater printed on them as a function of surface roughness after exposure to an exemplar realistic atmospheric diurnal cycle for up to one year. Methods to evaluate pitting damage included optical imaging, scanning electron microscopy imaging, profilometry analysis, and polarization scans. The developed cyclic exposure environment did not significantly influence pitting morphology nor depth in comparison to prior static exposure environments. Cross-hatching was observed in a majority of pits for all material compositions with the roughest surface finish (#4 finish) and in all surface finishes for the 304H composition. Evidence is provided that cross-hatched pit morphologies are caused by slip bands produced during the grinding process for the #4 finish or by material processing. Additionally, micro-cracking was observed in pits formed on samples with the #4 surface finish and was greatly reduced or absent for pits formed on samples with smooth surface finishes. This suggests that both a low RH leading to an MgCl 2 -dominated environment and a rough surface containing significant residual stress are necessary for micro-cracking. Finally, the use of various characterization techniques and cross sectioning was employed to both qualitatively and quantitatively assess pitting damage across all SS compositions and surface finishes.