Download or read book Effects of Helium DPA Ratio Alloy Composition and Cold Work on Microstructural Evolution and Hardening of 59Ni Doped Fe Cr Ni Alloys Neutron Irradiated at 465 C written by H. Kawanishi and published by . This book was released on 1996 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three ternary austenitic alloys(Fe-15Cr-25Ni, Fe-15Cr-25Ni-0.04P, Fe-15Cr-45Ni in both annealed and cold worked conditions) were irradiated at 465°C to 0.15, 0.28, and 0.42 dpa at above core position in the Fast Flux Test Facility utilizing the Materials Open Test Assembly to study the separate and synergistic effects of He/dpa ratio, phosphorus addition, nickel content and cold work level on microstructural evolution and hardening. The helium/dpa ratio was varied by isotopic doping with 59Ni to enhance the production rate of helium. The helium production rate was evaluated to be 62 appm He/dpa in the 59Ni-doped specimens and 0.26 appm He/dpa in the undoped specimens.
Download or read book Microstructural Evolution of Neutron Irradiated Fe Cr Ni Alloys at 495 C in Response to Changes in the Helium DPA Ratio written by FA. Garner and published by . This book was released on 1990 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: A series of three Fe-15Cr-XNi alloys in both annealed and cold worked conditions was irradiated in the fast flux test facility (FFTF) at 495°C to 14 dpa. The experiment was developed to determine the separate and synergistic effects of nickel and phosphorus content, cold work, and helium/dpa ratio. This experiment was conducted without introducing variations in displacement rate, a variable known to strongly influence microstructural evolution. Each alloy condition was irradiated in two variants, one with natural nickel and one enhanced with the 59Ni isotope. The latter variant produces helium/dpa ratios typical of fusion reactor spectra while the former yields a much lower level of helium. The results show that helium alters the microstructural evolution somewhat at 495°C, but its effect is relatively small compared to the influences of the other variables studied. Increases in starting dislocation density, nickel content, or phosphorus level all retard swelling temporarily while higher rates of helium generation usually, but not always, accelerate swelling. Phosphorus addition of 0.04 wt% not only decreased swelling but led to refinement of dislocation loop microstructure and stabilization of dislocation networks created by cold working. Phosphide precipitates did not form at this temperature and dose level.
Download or read book Metals Abstracts written by and published by . This book was released on 1995 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2726 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Influence of Helium Generation Rate and Temperature History on Mechanical Properties of Model Fe Cr Ni Alloys Irradiated in FFTF at Relatively Low Displacement Rates written by and published by . This book was released on 1993 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: In agreement with earlier studies conducted at higher displacement rates, evolution of mechanical properties of model Fe-Cr-Ni alloys irradiated at lower displacement rates in the 59Ni isotopic doping experiment does not appear to be strongly affected by large differences in helium generation rate. This insensitivity to helium/dpa ratio is exhibited during both isothermal and non-isothermal irradiation. The overall behavior of the model alloys used in this study is dominated by the tendency to converge to a saturation strength level that is independent of thermomechanical starting state and helium/dpa ratio, but which is dependent on irradiation temperature and alloy composition.
Download or read book The Effect of Helium on Microstructural Evolution and Mechanical Properties of Fe Cr Ni Alloys as Determined in a Spectral Tailoring Experiment written by and published by . This book was released on 1991 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fe-15Cr-XNi alloys irradiated at both low (0.66 to 1.2) and very high (27 to 58) helium/dpa levels exhibit significantly different levels of strengthening due to an unprecedented refinement of cavity microstructure at the very high helium levels. When compounded with the nickel dependence of helium generation, the cavity distribution for some irradiation conditions and alloy compositions can be driven below the critical radius for bubble-to-void conversion, leading to a delay in swelling. The critical radius also appears to be dependent on the nickel level. The refinement may not have resulted from the high helium levels alone, however but also may have been influenced by differences in displacement rate and temperature history in the two experiments.
Download or read book Influence of Cold Work and Phosphorus Content on Neutron induced Swelling of Fe Cr Ni Alloys written by and published by . This book was released on 1990 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: The overall objective of this effort was to determine the origin of the sensitivity of void swelling and microstructural evolution in irradiated metals to environmental and material variables. A more specific objective was to assist in the interpretation of the results of the 59Ni doping experiment designed to study the separate and synergistic effects of helium and other variables. Two of these variables are cold working and phosphorus content. 14 refs., 7 figs.
Download or read book Microstructural Evolution of Neutron irradiated Fe Cr Ni Ternary Alloys at High Helium Generation Rates written by and published by . This book was released on 1993 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: A series of Fe-Cr-Ni ternary alloy, were irradiated to 12-14 dpa in the Oak Ridge Research Reactor (ORR). In this experiment, most of helium atoms were produced by the 58Ni(n, [gamma])59Ni(n, [alpha])56Fe sequential reaction, and, therefore, the helium generation rate was almost proportional to the nickel content, ranging from 27 to 58 appm He/dpa in 20 to 45 wt.% Ni alloys. Irradiation temperatures were 330, 400, 500 and 600°C, and the specimen variables were the nickel level, the chromium level and cold working. The high levels helium, combined with details of the temperature history, were found to have dominated microstructural development, sometimes overwhelming and even reversing the action of a given material variable. Microscopy examination showed that there was an unprecedented refinement of cavity microstructure at all temperatures, which accounts for the substantial alterations in both swelling and mechanical properties observed in earlier studies.
Download or read book The Consequences of Helium Production and Nickel Additions on Microstructural Development in Isotopically Tailored Ferritic Alloys written by DS. Gelles and published by . This book was released on 1999 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: A series of alloys have been made adding various isotopes of nickel in order to vary the production of helium during irradiation by a two step nuclear reaction in a mixed spectrum reactor. The alloys use a base composition of Fe-12Cr with an addition of 1.5% nickel, either in the form of 60Ni which produces no helium, 59Ni which produces helium at a rate of about 10 appm He/dpa, or natural nickel which provides an intermediate level of helium due to delayed development of 59Ni. Specimens were irradiated in the HFIR at Oak Ridge, TN to 7.5 dpa at 300 and 400°C. Microstructural examinations indicated that nickel additions promote precipitation in all alloys, but the effect appears to be much stronger at 400°C than at 300°C. There is sufficient dose by 7 dpa (and with 2 appm He) to initiate void swelling in ferritic/martensitic alloys. Little difference was found between response from 59Ni and natural nickel. Also, helium bubble development for high helium generation conditions appeared to be very different at 300 and 400°C. At 300°C, it appeared that high densities of bubbles formed whereas at 400°C, bubbles could not be identified, possibly because of the complexity of the microstructure, but more likely because helium accumulated at precipitate interfaces.
Download or read book Influence of Composition Helium Generation Rate and Dpa Rate on Neutron Induced Swelling of Fe 15Cr 16Ni 0 25Ti Alloys in FFTF at approx 400 Degrees C written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Contrary to the behavior of swelling of f.c.c. Fe-15Cr-16Ni and Fe-15Cr-16Ni-0.25Ti alloys irradiated together in the same FFTF-MOTA experiment, Fe-15Cr-16Ti-0.25Ti-0.05C does not exhibit a dependence of swelling on dpa rate at [approx]400 C. The transient regime of swelling is prolonged by carbon addition, however. Addition of boron to the carbon-doped alloy decreases the swelling somewhat but does not restore the sensitivity to dpa rate. It appears that the primary influence of boron is chemical in nature, probably associated with boron's impact on the behavior of carbon. Boron's role as a source of helium is thought to be secondary.
Download or read book The Influence of Helium on Mechanical Properties of Model Austenitic Alloys Determined Using 59Ni Isotopic Tailoring and Fast Reactor Irradiation written by and published by . This book was released on 1991 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tensile testing on model Fe-Cr-Ni alloys removed from four discharges of the 59Ni isotopic doping experiment in FFTF indicates that helium/dpa ratios typical of fusion reactors do not produce changes in the yield strength or elongation that are significantly different from those at much lower helium generation rates. It also appears that tensile properties approach a saturation level that is dependent only on the final irradiation temperature, but not prior temperature history or thermomechanical starting condition. 14 refs., 4 figs., 1 tab.
Download or read book The Influence of Helium on Mechanical Properties of Model Austenitic Alloys Determined Using Sup 59 Ni Isotopic Tailoring and Fast Reactor Irradiation written by and published by . This book was released on 1991 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tensile testing on model Fe-Cr-Ni alloys removed from four discharges of the 59Ni isotopic doping experiment in FFTF indicates that helium/dpa ratios typical of fusion reactors do not produce changes in the yield strength or elongation that are significantly different from those at much lower helium generation rates. It also appears that tensile properties approach a saturation level that is dependent only on the final irradiation temperature, but not prior temperature history or thermomechanical starting condition. 14 refs., 4 figs., 1 tab.
Download or read book The Effects of Nickel on Microstructural Development and Microchemical Changes in Neutron Irradiated Fe Cr Mn Based Steels written by H. Takahashi and published by . This book was released on 1992 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microstructural changes and solute segregation in austenitic Fe-Cr-Mn-Ni alloys have been studied after neutron irradiation to 25 dpa (maximum) in FFTF/MOTA. Voids were nucleated in all of the specimens in the temperature range of 420 to 650°C, and a swelling peak was observed to form at 550°C. The void suppression effect of nickel additions did not occur in these alloys. Precipitates were formed in the matrix and/or on grain boundaries and were mostly identified as M23C6. The composition in the grain boundary area changed, and the chromium (Cr) concentration near the precipitates became higher. On the other hand, manganese and chromium were depleted, and nickel was enriched in the grain boundary area, but without precipitation. Other phases such as ferrite and sigma could not be recognized. Thus, it was revealed that the addition of nickel to Fe-Cr-Mn alloy stabilizes the austenite even in the grain boundary area where segregation is marked.
Download or read book Thermal and Mechanical Treatments for Nickel and Some Nickel base Alloys Effects on Mechanical Properties written by Albert M. Hall and published by . This book was released on 1972 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The Columbus Laboratories, Battelle Memorial Institute, originally prepared these reports in 1965 and later revised them, updating the information to include the latest technology through 1968. This report is one of a series pertaining to the fabricating of nickel, nickel-base, and cobalt-base alloys. This report deals with heat treating and working nickel and nickel-base alloys, and with the effects of these operations on the mechanical properties of the materials. The subjects covered are annealing, solution treating, stress relieving, stress equalizing, age hardening, hot working, cold working, combinations of working and heat treating (often referred to as thermomechanical treating), and properties of the materials at various temperatures. The equipment and procedures used in working the materials are discussed, along with the common problems that may be encountered and the precautions and corrective measures that are available."--Foreword.
Download or read book Neutron Induced Microstructural Evolution of Fe 15Cr 16Ni Alloys at 400 C During Neutron Irradiation in the FFTF Fast Reactor written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: An experiment conducted at ~400 degrees C on simple model austenitic alloys (Fe-15Cr-16Ni and Fe-15Cr-16Ni-0.25Ti, both with and without 500 appm boron) irradiated in the FFTF fast reactor at seven different dpa rates clearly shows that lowering of the atomic displacement rate leads to a pronounced reduction in the transient regime of void swelling. While the steady state swelling rate (~1%/dpa) of these alloys is unaffected by changes in the dpa rate, the transient regime of swelling can vary from
Download or read book The Influence of Nickel Content on Microstructures of Fe Cr Ni Austenitic Alloys Irradiated with Nickel Ions written by and published by . This book was released on 1990 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objectives of this effort is to identify the mechanisms involved in the radiation-induced evolution of microstructure in materials intended for fusion applications. The results of this study are useful in interpreting the results of several other ongoing experiments involving either spectral or isotopic tailoring to study the effects of helium on microstructure evolution. Ion-irradiated Fe-15Cr-XNi (X = 20, 35, 45, 60, 75) ternary alloys and a 15Cr-85Ni binary alloy were examined after bombardment at 675°C and compared to earlier observations made on these same alloys after irradiation in EBR-II at 510 or 538°C. The response of the ion-irradiated microstructures to nickel content appears to be very consistent with that of neutron irradiation even though there are four orders of magnitude difference in displacement rate and over 200°C difference in temperature. It appears that the transition to higher rates of swelling during both types of irradiation is related to the operation of some mechanisms that is not directly associated with void nucleation. 6 refs., 8 figs.
Download or read book Effect of Nickel on Irradiation Hardening and Microstructure Evolution of Proton Irradiated Fe Cu Alloys written by S. Yamaguchi and published by . This book was released on 2001 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hardness measurements and microstructure examinations of Fe(-C)-Cu-Ni model alloys were performed following 1 MeV proton irradiation below 80°C. Microstructural examinations by transmission electron microscope (TEM) were carried out by means of a cross section method. A band of damage structures, parallel to the irradiated surface, was observed at a depth of 6.5 ? m in agreement with calculation based on the TRIM code. TEM observation revealed that the band consisted of high density of small black spots, which were considered to be interstitial-type dislocation loops. The amount of irradiation hardening increased with increase in copper concentration. An addition of 0.6wt%Ni to Fe-Cu alloys further increased the hardening, although the effect was reduced with increasing copper concentration. Irradiation hardening of pure iron was also significantly increased by the addition of nickel. The size and number density of the spot-like structures in Fe-Cu alloys decreased and increased, respectively, with addition of nickel. Three recovery stages were found in Fe-Cu-Ni alloys during post-irradiation isochronal annealing to 675°C: the stages are at around 150°C, 400°C and 600°C. The first stage was only observed in nickel-containing alloys, while the third stage was only observed in copper-containing alloys. After annealing to 375°C, the density of spot-like structures decreased in Fe-Cu-Ni alloy but increased in Fe-Cu alloy, while for both the size of spots increased.
