Hydrogen effects on phase transformations in austenitic stainless steels

Rozenak, P.; Zevin, L.; Eliezer, D.

doi:10.1007/bf02403244

Cited by 51 publications

(19 citation statements)

References 10 publications

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“…It is well known that stress induced transformation from the fcc to the bcc structure occurs in SS304 [9][10][11]. In the present experiment, however, no peaks due to the bcc structure were observed by XRD measurement in all the samples after any fatigue cycles.…”

Section: Fatigue Cyclecontrasting

confidence: 50%

Positron Annihilation Study in the Early Stage of Fatigue in Type 304 Stainless Steel

Hori

Oshima

2002

phys. stat. sol. (a)

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Subject classification: 61.72.Ji; 62.20.Mk; 78.70.Bj; S1.1Positron annihilation lifetime and Doppler broadening measurements have been performed to study the early stage of fatigue in type 304 stainless steel at various positions of samples at room temperature. Both the average lifetime of positron and the S parameter have increased with increasing number of fatigue cycles at each position. From two-lifetime component analysis, the component of the longer lifetime of about 170 ps, corresponding to single or di-vacancies, has been observed from 0.01% Nf fatigue, and it has remained stable until 10% Nf of the fatigue life. However, the lifetime has increased rapidly to about 230 ps toward a fatigue life of about 20% Nf at a certain position of the sample. Vacancy clusters have possibly been formed to some extent at this fatigue life. Moreover, the fatigue failure has occurred at almost the same position as the one where the longer positron lifetime was observed. These results suggest that the generation of micro cracks during fatigue test is related to the formation of three-dimensional vacancy clusters. Detailed measurements of positron lifetime and Doppler broadening, have also been carried out for small areas of fractured samples. From these experiments, it has been found that stress concentration occurred at a central position of a sample during fatigue and that this can be probed by the increase of the positron lifetime.

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Section: Fatigue Cyclecontrasting

confidence: 50%

Positron Annihilation Study in the Early Stage of Fatigue in Type 304 Stainless Steel

Hori

Oshima

2002

phys. stat. sol. (a)

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“…The appearance of those new phases was seen in previous research on duplex stainless steel [3,[19][20][21] and austenitic stainless steel [10,12,13,22]. Previously published works have identified the c ⁄ phase as a hydrogen-enriched austenitic phase, which is derived from the initial c-phase [10,12,23]. After 1 month aging at RT, the c ⁄ reflections decrease and those of the c phase increase in intensity and decreased in breadth; the c line positions shifted to higher 2h values, indicating a recovery in lattice expansion (decreasing lattice parameter compared with the as received sample), as shown in Fig.…”

Section: Hydrogen-induced Phase Transformation In Lean Duplex Stainlementioning

confidence: 71%

“…Simultaneously, the appearance of new phases including the rich hydrogen e H -martensite with hcp crystal structure and the c ⁄ , an additional fcc phase with a 5% higher lattice parameter, are seen. The appearance of those new phases was seen in previous research on duplex stainless steel [3,[19][20][21] and austenitic stainless steel [10,12,13,22]. Previously published works have identified the c ⁄ phase as a hydrogen-enriched austenitic phase, which is derived from the initial c-phase [10,12,23].…”

Section: Hydrogen-induced Phase Transformation In Lean Duplex Stainlementioning

confidence: 80%

“…Hydrogen has different effects on the a and c phases. In addition, it is known that the stability of the c phase, which can have a significant effect on the material's properties, is affected both by the steel composition and by the presence of hydrogen in solid solution [10][11][12][13][14]. In order to initiate a crack, a critical hydrogen concentration must be reached at potential crack sites.…”

Section: Introductionmentioning

confidence: 99%

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Hydrogen trapping mechanism of different duplex stainless steels alloys

Silverstein

Eliezer

2015

Journal of Alloys and Compounds

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“…This lattice parameter is about 5.5 pct greater than that reported for the e-phase obtained athermally or by plastic deformation. [41] On the diffractograms taken after charging, a splitting of broadened c/c* and e/e* diffraction peaks was observed. [18] During the aging, as the hydrogen diffused out of the specimen, the lattice parameter decreased, as shown by the shift of both c and e reflections to larger 2h values.…”

Section: Resultsmentioning

confidence: 97%

Effect of Gas Tungsten Arc Welding Parameters on Hydrogen-Assisted Cracking of Type 321 Stainless Steel

Rozenak

Unigovski

Shneck

2016

Metall Mater Trans A

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The susceptibility of AISI type 321 stainless steel welded by the gas tungsten arc welding (GTAW) process to hydrogen-assisted cracking (HAC) was studied in a tensile test combined with in situ cathodic charging. Specimen charging causes a decrease in ductility of both the as-received and welded specimens. The mechanical properties of welds depend on welding parameters. For example, the ultimate tensile strength and ductility increase with growing shielding gas (argon) rate. More severe decrease in the ductility was obtained after post-weld heat treatment (PWHT). In welded steels, in addition to discontinuous grain boundary carbides (M 23 C 6 ) and dense distribution of metal carbides MC ((Ti, Nb)C) precipitated in the matrix, the appearance of delta-ferrite phase was observed. The fracture of sensitized specimens was predominantly intergranular, whereas the as-welded specimens exhibited mainly transgranular regions. High-dislocation density regions and stacking faults were found in delta-ferrite formed after welding. Besides, thin stacking fault plates and epsilon-martensite were found in the austenitic matrix after the cathodic charging.

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Hydrogen effects on phase transformations in austenitic stainless steels

Cited by 51 publications

References 10 publications

Positron Annihilation Study in the Early Stage of Fatigue in Type 304 Stainless Steel

Positron Annihilation Study in the Early Stage of Fatigue in Type 304 Stainless Steel

Hydrogen trapping mechanism of different duplex stainless steels alloys

Effect of Gas Tungsten Arc Welding Parameters on Hydrogen-Assisted Cracking of Type 321 Stainless Steel

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