Download or read book Effect of Heavy Ion Irradiation on Microstructural Evolution in CF8 Cast Austenitic Stainless Steel written by and published by . This book was released on 2015 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: The microstructural evolution in ferrite and austenitic in cast austenitic stainless steel (CASS) CF8, as received or thermally aged at 400 °C for 10,000 h, was followed under TEM with in situ irradiation of 1 MeV Kr ions at 300 and 350 °C to a fluence of 1.9 × 1015 ions/cm2 (~3 dpa) at the IVEM-Tandem Facility. For the unaged CF8, the irradiation-induced dislocation loops appeared at a much lower dose in the austenite than in the ferrite. At the end dose, the austenite formed a well-developed dislocation network microstructure, while the ferrite exhibited an extended dislocation structure as line segments. Compared to the unaged CF8, the aged specimen appeared to have lower rate of damage accumulation. The rate of microstructural evolution under irradiation in the ferrite was significantly lower in the aged specimen than in the unaged. Finally, we attributed this difference to the different initial microstructures in the unaged and aged specimens, which implies that thermal aging and irradiation are not independent but interconnected damage processes.
Download or read book Effect of Ti and C on the Microstructural Evolution of Rapidly Solidified Austenitic Stainless Steels Under Dual Ion Irradiation written by Chiang-Hsiung Tong and published by . This book was released on 1983 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Microstructural Evolution of Austenitic Stainless Steels Irradiated in a Fast Reactor written by OV. Borodin and published by . This book was released on 1996 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Analysis of the microstructure of the stainless steels 16Cr15Ni3MoNb and 18Cr10NiTi, irradiated at temperatures where changes in phase stability occur due to radiation-induced segregation, shows that the stability of second-phase particles depends on the structure of particle-matrix interface.
Download or read book A Composite Model of Microstructural Evolution in Austenitic Stainless Steel Under Fast Neutron Irradiation written by GR. Odette and published by . This book was released on 1987 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: A rate-theory-based model has been developed which includes the simultaneous evolution of the dislocation and cavity components of the microstructure of irradiated austenitic stainless steels. Previous work has generally focused on developing models for void swelling while neglecting the time dependence of the dislocation structure. These models have broadened our understanding of the physical processes that give rise to swelling, for example, the role of helium and void formation from critically-sized bubbles. That work has also demonstrated some predictive capability by successful calibration to fit the results of fast reactor swelling data. However, considerable uncertainty about the values of key parameters in these models limits their usefulness as predictive tools. Hence, the use of such models to extrapolate fission reactor swelling data to fusion reactor conditions is compromised.
Download or read book Microstructural Development of Titanium Modified Austenitic Stainless Steel Under Neutron Irradiation in HFIR Up to 57 Dpa written by S. Hamada and published by . This book was released on 1990 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Japanese prime candidate alloy (JPCA). a titanium-modified austenitic stainless steel, has shown good performance after irradiation in the high flux isotope reactor (HFIR) up to 34 dpa at 300 to 600°C, but considerable void swelling develops in solution annealed (SA) JPCA after irradiation to 57 dpa at 500°C. However, cold worked (CW) or cold worked and aged (CW + A) JPCA still demonstrates good performance after similar irradiation. Swelling resistance appears to depend strongly on the behavior of fine titanium-rich MC precipitates. This paper describes the microstructural evolution process observed in the JPCA steel during HFIR irradiation. The onset of rapid void swelling was related to MC precipitate dissolution, and the instability of the MC was interpreted in terms of a model involving the build and subsequent effects of a solute segregation zone in the matrix surrounding the precipitate particle.
Download or read book Composite Model of Microstructural Evolution in Austenitic Stainless Steel Under Fast Neutron Irradiation written by and published by . This book was released on 1986 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A rate-theory-based model has been developed which includes the simultaneous evolution of the dislocation and cavity components of the microstructure of irradiated austenitic stainless steels. Previous work has generally focused on developing models for void swelling while neglecting the time dependence of the dislocation structure. These models have broadened our understanding of the physical processes that give rise to swelling, e.g., the role of helium and void formation from critically-sized bubbles. That work has also demonstrated some predictive capability by successful calibration to fit the results of fast reactor swelling data. However, considerable uncertainty about the values of key parameters in these models limits their usefulness as predictive tools. Hence the use of such models to extrapolate fission reactor swelling data to fusion reactor conditions is compromised.
Download or read book Microstructural Evolution in Fast neutron irradiated Austenitic Stainless Steels written by Roger E. Stoller and published by . This book was released on 1987 with total page 357 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Void Precipitate Association During Neutron Irradiation of Austenitic Stainless Steel written by PJ. Maziasz and published by . This book was released on 1987 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microstructural data have recently become available on a single heat of 316 stainless steel irradiated in EBR-II and HFIR, over a wide range of irradiation temperatures (55 to 750°C), doses (7 to 75 dpa), and several helium generation rates (0.5 to 55 atomic ppm He/dpa). Results on just one heat of steel minimize effects that may be related to compositional differences. In this work we present these data in order to offer a characterization of precipitate-void association within the context of the overall microstructural evolution. Observations on a second heat of steel are also presented here to allow us to assess which microstructural correlations are general. The analysis of experimental results leads us, first, to conclude that precipitate-void association is not only dependent upon local conditions at the precipitate interface but is also strongly related to the overall microstructural evolution. Second, we suggest a precipitation mechanism that helps to understand precipitate-void codevelopment.
Download or read book The Combined Effects of Temperature and Irradiation on the Mechanical Properties of Austenitic Stainless Steels written by J. E. Irvin and published by . This book was released on 1965 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Radiation Hardening Effects on Localized Deformation and Stress Corrosion Cracking of Stainless Steels written by and published by . This book was released on 1993 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radiation hardening in austenitic stainless steels modifies deformation characteristics and correlate well with increased susceptibility to intergranular stress corrosion cracking (IGSCC). Available data on neutron-irradiated materials have been analyzed and correlations developed between fluence, yield strength, and cracking susceptibility in high-temperature water environments. Large heat-to-heat differences in critical fluence (0.2 to 2.5 x 1021 n/cm2) for IGSCC are documented. In many cases, this variability is consistent with yield strength differences among irradiated materials. IGSCC correlates better to yield strength than to fluence for most heats suggesting a possible role of radiation-induced hardening (and microstructure) on cracking. Microstructural evolution during proton and heavy-ion irradiation has been characterized in low-carbon 302SSs. Hardening results from dislocation loops. SEM and TEM are used to examine dose, strain, and temperature effects on deformation. This hardened microstructure produces inhomogeneous planar deformation within the matrix. Regularly spaced steps are created at the surface during deformation which increase in number with increasing macroscopic strain. Twinning is the dominant deformation mechanism at low temperature, while dislocation channeling is observed at 288C. Deformation characteristics are discussed in terms of potential impact on IGSCC.
Download or read book The Observation and Interpretation of Microstructural Evolution and Swelling in Austenitic Steels Under Irradiation written by N. Sekimura and published by . This book was released on 1994 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Irradiation behavior of model austenitic steels is investigated to establish mechanistic modeling of swelling and other property changes under irradiation. Neutron irradiation experiments were performed using Material Open Test Assembly (MOTA) at 693, 793 and 873 K to 35 to 40 dpa in the Fast Flux Test Facility (FFTF) cycles 10 and 11. Cavity formation and dislocation development were quantitatively estimated to evaluate the effect of temperature history on the microstructural evolution under irradiation in fission reactors. Fine dislocation loops observed in the matrix of the alloys irradiated in cycle 10 were considered to come from the low-temperature irradiation during the reactor shut-down at the end of the cycle. Very few small loops were detected in identical specimens irradiated in FFTF cycle 11 where the reactor power and temperature were simultaneously decreased a short time during the shut-down.
Download or read book Microstructural Evolution of Austenitic Stainless Steels Irradiated to 17 Dpa in Spectrally Tailored Experiment of the ORR and HFIR at 400 degrees C written by and published by . This book was released on 1997 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The microstructural evolution of austenitic JPCA aged and solution annealed JPCA, 316R, C, K, and HP steels irradiated at 400°C in spectrally tailored experiments of the ORR and HFIR has been investigated. The helium generation rates were about 12-16 appm He/dpa on the average up to 17.3 dpa. The number densities and average diameters of dislocation loops in the steels have ranges of 3.3 x 1021 m−3 and 15.2-26.3 nm, respectively, except for HP steel for which they are 1.1 x 1023 m−3 and 8.0 nm. Precipitates are formed in all steels except for HP steel, and the number densities and average diameters have ranges of 5.2 x 102° - 7.7 x 1021 m−3 and 3.4- 19.3 nm, respectively. In the 216R, C, and K steels, the precipitates are also formed at grain boundaries, and the mean sizes of these are about 110, 50, and 50 nm, respectively. The number densities of cavities are about 1 x 1022 m−3 in all the steels. The swelling is low in the steels which form the precipitates.
Download or read book Effects of Applied Stress on Microstructural Evolution in 316SS Under Ion Irradiation written by Y. Katoh and published by . This book was released on 1994 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: To obtain fundamental knowledge about the stress effects on microstructural behavior in irradiated materials, we developed a tensile loading apparatus which is to be mounted on the dual-ion irradiation stage of the High-fluence Irradiation Facility of the University of Tokyo and established a corresponding experimental method. In the first part of this paper, a description of the facility and the experimental technique are given.
Download or read book Effects of Grain Size on Strain Induced Microstructural Evolution in Type 304 Austenitic Stainless Steel written by David Christopher Murdock and published by . This book was released on 2003 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Variations of Phase and Structure in Austenitic Stainless Steel Under Heavy Ion Irradiation written by IM. Neklyudov and published by . This book was released on 1990 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The paper presents a brief survey of the authors' results in the study of the evolution of dislocation, phase and void structures in austenitic stainless steels under heavy ion irradiation. Stainless steels of the types, Cr18Nil0Ti, Cr16Nil5Mo3Nb. and Cr16NillMo3, in different structural environments were studied. The analysis of structure and composition of unirradiated and irradiated specimens was made using a 100-keV transmission electron microscope (TEM-100) with a spectrometer, "Link Systems 860.".
Download or read book Microstructure Modeling of a 316L Stainless Steel Irradiated with Electrons written by J. Henry and published by . This book was released on 2000 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work presented here is a first step in an effort to develop a rate theory model useful for the prediction of microstructural evolution of austenitic stainless steels in typical irradiation conditions for PWR core internals. An important difficulty associated with this type of model is the lack of well known material parameters (apparent defect migration energies, bias factors, etc.), which depend on the composition of the alloy and on the presence of impurities. The approach adopted here consists in finding an adequate set of parameters which results in a good agreement between model predictions and microstructural data after irradiating a 316L stainless steel at different temperatures in a 1 MeV electron microscope. Model results can then be compared with microstructural data corresponding to different irradiation conditions. We have chosen here to perform irradiations at low damage rate using 3 MeV electrons, which is a simpler case compared for example with neutron irradiations. We have found that calculated and measured densities of interstitial loops are in good agreement if a small fraction of the generated defects is considered to be in the form of di-interstitials, in accordance with molecular dynamics results. In the future, we intend to modify the model for the case of neutron irradiations. The same procedure as implemented here for the choice of material parameters (i.e., 1 MeV electron irradiations) will be carried out for different types of austenitic stainless steels. Model predictions will then be compared with microstructural observations obtained after irradiations of the steels up to different doses in an experimental reactor.
Download or read book Precipitation and Cavity Formation in Austenitic Stainless Steels During Irradiation written by and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Microstructural evolution in austenitic stainless steels subjected to displacement damage at high temperature is strongly influenced by the interactions between helium atoms and second phase particles. Cavity nucleation occurs by the trapping of helium at partially coherent particle-matrix interfaces. The recent precipitate point defect collector theory describes the more rapid growth of precipitate-attached cavities compared to matrix cavities where the precipitate-matrix interface collects point defects to augment the normal point deflect flux to the cavitry. Data are presented which support these ideas. It is shown that during nickel ion irradiation of a titanium-modified stainless steel at 675°C the rate of injection of helium has a strong effect on the total swelling and also on the nature and distribution of precipitate phases.
