Dose dependence of the microstructural evolution in neutron-irradiated austenitic stainless steel

Zinkle, S.J.; Maziasz, P.J.; Stoller, R.E.

doi:10.1016/0022-3115(93)90128-l

Cited by 346 publications

(159 citation statements)

References 61 publications

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“…The presence of the dislocation network in the SACW sample may have reduced the mobility of the radiation-induced point defects that eventually form dislocation loops. As reported for cold-worked irradiated steels, a significant reduction of the initial dislocation network is required for the development of observable dislocation loops [31].…”

Section: ) Direct Comparison With the Results Of Neutron-irradiatiomentioning

confidence: 72%

Monolayer-thick TiO precipitation in V-4Cr-4Ti alloy induced by proton irradiation

et al. 2017

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We have characterised to atomic resolution the mono-layer thick TiO-type precipitate induced by proton irradiation in V-4Cr-4Ti alloy at the coarsening radiation-induced interstitial a/2⟨111⟩ dislocation loops expected to exert a minimal effect on the precipitate formation. This monolayer-thick precipitate constitutes an early stage in the radiationinduced aging process of V-4Cr-4Ti at low temperatures, and can potentially absorb additional light elements in reactor environments. 1Moor Row, November 24, 2016 Dear Prof. Beyerlein, Please find attached the resubmitted manuscript SMM-16-1716 entitled 'Monolayer-thick TiO precipitation in V-4Cr-4Ti alloy induced by proton irradiation' which has been significantly revised on the basis of the comments received by the reviewers.The detailed response to the reviewers' comments, together with the revised version of the manuscript, is attached. We would like to thank the reviewers for their time and effort in appraising the manuscript. The comments received were pertinent and helpful in improving the manuscript. All the points raised have been addressed and the manuscript has been amended accordingly. We believe that the revisions made adequately address the points raised and should therefore present no further obstacle to publication. We thank the reviewers for carefully reading the manuscript and the useful comments. We have addressed all those comments, which we feel have improved the article's quality.Detailed response:1.) In figure 2, images for SA and SACW irradiated at 350C are necessary for better understanding of temperature effects. We have included additional text in the manuscript about the temperature effect. The novelty and impact of this work lies in the recovery of the CWed structure already at 300°C (Fig. 2) before the formation of monolayer-thick RIPs at 350°C (Fig. 3). 2.) What is the relationship between the observed microstructure and the hardness? For example, for SA irradiated at 300C and 350C, where does the difference in hardening come?We have added some text to clarify the observed hardening behaviour at different temperatures in terms of the observed microstructure. 3.) As the observed RIPs in this study is platelet, the description as "average size" may mislead.We have changed the average size of the monolayer-thick RIPs by their average length. 4.) The description about recovery of the pre-existing dislocation network in SACW is contradicting in page 6 and page 7.We have clarified the contradiction in page 6 and 7. 5.) Direct comparison with the results of neutron-irradiation might be difficult since the damage rate is exceedingly large.We have added some text about the difference in dose rate and particle fluence between neutron and proton irradiation. The formation and evolution of a/2 ⟨111⟩ unfaulted dislocation loops in our proton irradiated samples correspond to the observations reported in neutron-irradiated material. However the average loop size at 350C in the proton irradiated samples (85nm) is lower than the value repo...

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Section: ) Direct Comparison With the Results Of Neutron-irradiatiomentioning

confidence: 72%

Monolayer-thick TiO precipitation in V-4Cr-4Ti alloy induced by proton irradiation

et al. 2017

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“…The results are summarized as follows: (1) The angular distribution of step angle obtained experimentally showed a low correlation with that predicted using the NC model, in which the crystal was assumed to slip in an arbitrary direction and inhomogeneous local stress was not considered. (2) It is possible to predict the angular distribution by using the PC model, in which the inhomogeneous local stress obtained by FEA and possible step angles determined by crystallographic orientation are considered. This model suggested that not only RSS but also the normal stress acting on the slip plane affects the crystallographic slip.…”

Section: Discussionmentioning

confidence: 99%

“…For example, the yield strength is increased and the ductility is decreased by defect clusters, such as dislocation loops, induced by neutron irradiation. 1,2) Such an irradiated stainless steel exhibits highly localized deformation at the microstructural level, since the number of active slips is limited by defect clusters that impede glide dislocations. Irradiated stainless steels are susceptible to intergranular cracking even in an inert gas environment, and irradiation-assisted stress corrosion cracking (IASCC) often takes place in a high-temperature water environment.…”

Section: Introductionmentioning

confidence: 99%

Angular Distribution of Slip Steps by Three-Dimensional Polycrystalline Model for Stainless Steel

Kamaya¹,

Fukuya²,

Kitamura

2009

Journal of Nuclear Science and Technology

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Localized deformation plays an important role in the initiation of irradiation-assisted stress corrosion cracking, and it can be characterized by the spacing and inclination of slip steps observed on the surface. In order to examine the contribution of mechanical factors (stress) to slipping, the angular distribution of slip steps was evaluated by using a three-dimensional polycrystalline model generated by Voronoi tessellation. An elastic finite element analysis was performed to derive the resolved shear stress (RSS) acting on each slip system. Random crystallographic orientations assigned to each grain caused the microstructural inhomogeneity of local stress due to anisotropic elastic properties. The angular distribution obtained was compared with the experimental results observed in irradiated and deformed stainless steel. It was shown that mechanical factors dominate the slipping behavior of the irradiated stainless steel and that not only RSS but also normal stress acting on the slip plane affects the crystallographic slip. The angular distribution was also evaluated from the maximum Schmid factor of individual grains, in which the inhomogeneous local stress was not taken into account. The angular distributions obtained using RSS and the Schmid factor were almost the same. This suggests that the inhomogeneity of local stress negligibly affects the angular distribution of slip steps, although the change in the local stress in the polycrystalline material is significant.

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“…The fine defect damage reaches its saturation level very quickly during irradiation. [61] The rapid removal of a dense population of small obstacles impeding dislocation motion could result in a change in deformation mode and, hence, cracking behavior during annealing. This is consistent with the work of Bailat et al, [62] who reported a possible correlation between deformation mode and IASCC in neutron-irradiated stainless steels.…”

Section: Implications For Iasccmentioning

confidence: 99%

“…There is little data on microstructure development at low temperatures, although in a review paper, Zinkle [64] notes that the saturation density of small defect clusters may be greater than 10 24 m -3 , and that this density is attained after doses of about 0.1 dpa. Further, the data from Higgy and Hammad [65] suggest that mechanical property measurements on 304 and 316 SS after neutron irradiation at <100°C suggest that defect cluster saturation occurs before 0.1 dpa, consistent with the results of this study.…”

Section: Isolating the Dislocation Microstructurementioning

confidence: 99%

Mechanism of Irradiation Assisted Cracking of Core Components in Light Water Reactors

Was¹,

Atzmon²

2003

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Executive SummaryThe overall goal of the project is to determine the mechanism of irradiation assisted stress corrosion cracking (IASCC). IASCC has been linked to hardening, microstructural and microchemical changes during irradiation. Unfortunately, all of these changes occur simultaneously and at similar rates during irradiation, making attribution of IASCC to any one of these features nearly impossible to determine. The strategy set forth in this project is to develop means to separate microstructural from microchemical changes to evaluate each separately for their effect on IASCC. In the first part, post irradiation annealing (PIA) treatments are used to anneal the irradiated microstructure, leaving only radiation induced segregation (RIS) for evaluation for its contribution to IASCC. The second part of the strategy is to use low temperature irradiation to produce a radiation damage dislocation loop microstructure without radiation induced segregation in order to evaluate the effect of the dislocation microstructure alone.A radiation annealing model was developed based on the elimination of dislocation loops by vacancy absorption. Results showed that there were indeed, time-temperature annealing combinations that leave the radiation induced segregation profile largely unaltered while the dislocation microstructure is significantly reduced. Proton irradiation of 304 stainless steel irradiated with 3.2 MeV protons to 1.0 or 2.5 dpa resulted in grain boundary depletion of chromium and enrichment of nickel and a radiation damaged microstructure. Post irradiation annealing at temperatures of 500 -600°C for times of up to 45 min. removed the dislocation microstructure to a greater degree with increasing temperatures, or times at temperature, while leaving the radiation induced segregation profile relatively unaltered. Constant extension rate tensile (CERT) experiments in 288°C water containing 2 ppm O 2 and with a conductivity of 0.2 mS/cm and at a strain rate of 3 x 10 -7 s -1 showed that the IASCC susceptibility, as measured by the crack length per unit strain, decreased with very short anneals and was almost completely removed by an anneal at 500°C for 45 min. This annealing treatment removed about 15% of the dislocation microstructure and the irradiation hardening, but did not affect the grain boundary chromium depletion or nickel segregation, nor did it affect the grain boundary content of other minor impurities. These results indicate that RIS is not the sole controlling feature of IASCC in irradiated stainless steels in normal water chemistry. DE-FG07-99ID13768Final Report 3The isolation of the irradiated microstructure was approached using low temperature irradiation or combinations of low and high temperature irradiations to achieve a stable, irradiated microstructure without RIS. Experiments were successful in achieving a high degree of irradiation hardening without any evidence of RIS of either major or minor elements. The low temperature irradiations to doses up to 0.3 dpa at T<75°C were also very succ...

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Dose dependence of the microstructural evolution in neutron-irradiated austenitic stainless steel

Cited by 346 publications

References 61 publications

Monolayer-thick TiO precipitation in V-4Cr-4Ti alloy induced by proton irradiation

Monolayer-thick TiO precipitation in V-4Cr-4Ti alloy induced by proton irradiation

Angular Distribution of Slip Steps by Three-Dimensional Polycrystalline Model for Stainless Steel

Mechanism of Irradiation Assisted Cracking of Core Components in Light Water Reactors

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