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Sample records for ods superalloy sheet

  1. Recrystallization of the ODS superalloy PM-1000

    International Nuclear Information System (INIS)

    Sandim, H.R.Z.; Hayama, A.O.F.; Raabe, D.

    2006-01-01

    The primary recrystallization of a -fiber textured coarse-grained oxide dispersion strengthened nickel-based superalloy (PM-1000) has been investigated by high-resolution electron backscatter diffraction. The annealing behavior of this alloy is quite complex. Even at high annealing temperatures (e.g. 1200 deg. C), recrystallization is only partial. The microstructure of this superalloy in the annealed state consists of a blurred subgrain structure, coarse grains with sizes of about 10-20 μm at the pre-existing grain boundaries and a significant fraction of small crystals in the interior of the recovered grains. These small grains are elongated and display anisotropic growth. In the present paper we present a detailed explanation for this peculiar microstructure. Particular focus is placed on the origin of the new grains in the recovered structure in a [1 0 0]-oriented grain

  2. Characterisation of As-deformed microstructure of ODS NI-Base superalloy and ODS ferritic steel prior to directional recrystallisation

    International Nuclear Information System (INIS)

    Baloch, M.M.; Memon, S.A.

    2007-01-01

    The materials studied are unusual in the sense that they have been prepared from mechanically alloyed procedures, including compaction and hot extrusion. It was felt necessary to characterise the initial microstructure thoroughly prior to directional recrystallisation of the alloys. Following consolidation by hot extrusion, dispersion strengthened superalloys appear to display a very fine sub-micron grain size consisting of both dislocation free recrystallised material and un- recrystallised regions of high dislocation density. It is found that there is a very fine dislocation cell structure in the ODS (Oxide Dispersion Strengthened) Ferritic stainless Steel prior to recrystallisation treatment, which shows that alloy is in old-deformed condition after mechanical alloying, extrusion I hot-working. This is in contrast to the mechanically alloyed Nickel Base Superalloy, which have consistently been found to be in primary recrystallisation state following extrusion. In order to understand the recrystallisation behaviour of the two mechanically illoyed materials with commercial designations MA6000 and MA956, a measurement of the orientation relationship between adjacent grains in the as- deformed ODS alloys has also been carried out using Transmission Electron microscope. (author)

  3. Fabrication development for ODS-superalloy, air-cooled turbine blades

    Science.gov (United States)

    Moracz, D. J.

    1984-01-01

    MA-600 is a gamma prime and oxide dispersion strengthened superalloy made by mechanical alloying. At the initiation of this program, MA-6000 was available as an experimental alloy only and did not go into production until late in the program. The objective of this program was to develop a thermal-mechanical-processing approach which would yield the necessary elongated grain structure and desirable mechanical properties after conventional press forging. Forging evaluations were performed to select optimum thermal-mechanical-processing conditions. These forging evaluations indicated that MA-6000 was extremely sensitive to die chilling. In order to conventionally hot forge the alloy, an adherent cladding, either the original extrusion can or a thick plating, was required to prevent cracking of the workpiece. Die design must reflect the requirement of cladding. MA-6000 was found to be sensitive to the forging temperature. The correct temperature required to obtain the proper grain structure after recrystallization was found to be between 1010-1065 C (1850-1950 F). The deformation level did not affect subsequent crystallization; however, sharp transition areas in tooling designs should be avoided in forming a blade shape because of the potential for grain structure discontinuities. Starting material to be used for forging should be processed so that it is capable of being zone annealed to a coarse elongated grain structure as bar stock. This conclusion means that standard processed bar materials can be used.

  4. Sintering and microstructure evolution of columnar nickel-based superalloy sheets prepared by EB-PVD

    International Nuclear Information System (INIS)

    Chen, S.; Qu, S.J.; Liang, J.; Han, J.C.

    2010-01-01

    Research highlights: → EB-PVD technology is commonly used to deposit thermal barrier coatings (TBCs) and columnar structure is commonly seen in EB-PVD condensates. The unique columnar structure can provide outstanding resistance against thermal shock and mechanical strains for TBCs. However, a number of researchers have found that the columnar structure can affect the mechanical properties of EB-PVD alloy thin sheet significantly. As yet, works on how to reduce this kind of effects are seldom done. In the present article, we tried to reveal the sintering effects on microstructure evolution and mechanical properties of columnar Ni-based superalloy sheet. The results suggests that after sintering, the columnar structure degrades. Degradation depends on sintering temperature and time. Both the ultimate tensile strength and the elongation percentage are effectively improved after sintering. - Abstract: A ∼0.15 mm-thick columnar nickel-based superalloy sheet was obtained by electron beam physical vapor deposition (EB-PVD). The as-deposited alloy sheet was sintered at different conditions. The microstructure of the specimens before and after sintering was characterized by using scanning electron microscopy. An X'Pert texture facility was used to determine the crystallographic orientation of the as-deposited alloy sheet. The phase transformation was investigated by X-ray diffraction. Tensile tests were conducted at room temperature on as-deposited and sintered specimens. The results show that the as-deposited sheet is composed of typical columnar structures. After sintering, however, the columnar structure degrades. The degradation depends on sintering temperature and time. Both the ultimate tensile strength and the elongation percentage are effectively improved after sintering.

  5. MICROSTRUCTURE AND MECHANICAL STRENGTH OF SURFACE ODS TREATED ZIRCALOY-4 SHEET USING LASER BEAM SCANNING

    Directory of Open Access Journals (Sweden)

    HYUN-GIL KIM

    2014-08-01

    Full Text Available The surface modification of engineering materials by laser beam scanning (LBS allows the improvement of properties in terms of reduced wear, increased corrosion resistance, and better strength. In this study, the laser beam scan method was applied to produce an oxide dispersion strengthened (ODS structure on a zirconium metal surface. A recrystallized Zircaloy-4 alloy sheet with a thickness of 2 mm, and Y2O3 particles of 10 μm were selected for ODS treatment using LBS. Through the LBS method, the Y2O3 particles were dispersed in the Zircaloy-4 sheet surface at a thickness of 0.4 mm, which was about 20% when compared to the initial sheet thickness. The mean size of the dispersive particles was 20 nm, and the yield strength of the ODS treated plate at 500°C was increased more than 65 % when compared to the initial state. This strength increase was caused by dispersive Y2O3 particles in the matrix and the martensite transformation of Zircaloy-4 matrix by the LBS.

  6. Research on Liquid Forming Process of Nickel Superalloys Thin Sheet Metals

    Directory of Open Access Journals (Sweden)

    Hyrcza-Michalska M.

    2017-12-01

    Full Text Available The paper presents the study of drawability of thin sheet metals made of a nickel superalloy Inconel type. The manufacturing process of axisymmetric cup – cone and a closed section profile in the form of a circular tube were designed and analyzed. In both cases, working fluid-oil was used in place of the rigid tools. The process of forming liquid is currently the only alternative method for obtaining complex shapes, coatings, and especially if we do it with high-strength materials. In the case of nickel superalloys the search for efficient methods to manufacture of the shaped shell is one of the most considerable problems in aircraft industry [1-5]. However, the automotive industries have the same problem with so-called advanced high-strength steels (AHSS. Due to this, both industrial problems have been examined and the emphasis have been put on the process of liquid forming (hydroforming. The study includes physical tests and the corresponding numerical simulations performed, using the software Eta/Dynaform 5.9. Numerical analysis of the qualitative and quantitative forecasting enables the formability of materials with complex and unusual characteristics of the mechanical properties and forming technology. It has been found that only the computer aided design based on physical and numerical modeling, makes efficient plastic processing possible using a method of hydroforming. Drawability evaluation based on the determination of the mechanical properties of complex characteristics is an indispensable element of this design in the best practice of industrial manufacturing products made of thin sheet metals.

  7. Laser Cladding of Ultra-Thin Nickel-Based Superalloy Sheets.

    Science.gov (United States)

    Gabriel, Tobias; Rommel, Daniel; Scherm, Florian; Gorywoda, Marek; Glatzel, Uwe

    2017-03-10

    Laser cladding is a well-established process to apply coatings on metals. However, on substrates considerably thinner than 1 mm it is only rarely described in the literature. In this work 200 µm thin sheets of nickel-based superalloy 718 are coated with a powder of a cobalt-based alloy, Co-28Cr-9W-1.5Si, by laser cladding. The process window is very narrow, therefore, a precisely controlled Yb fiber laser was used. To minimize the input of energy into the substrate, lines were deposited by setting single overlapping points. In a design of experiments (DoE) study, the process parameters of laser power, laser spot area, step size, exposure time, and solidification time were varied and optimized by examining the clad width, weld penetration, and alloying depth. The microstructure of the samples was investigated by optical microscope (OM) and scanning electron microscopy (SEM), combined with electron backscatter diffraction (EBSD) and energy dispersive X-ray spectroscopy (EDX). Similarly to laser cladding of thicker substrates, the laser power shows the highest influence on the resulting clad. With a higher laser power, the clad width and alloying depth increase, and with a larger laser spot area the weld penetration decreases. If the process parameters are controlled precisely, laser cladding of such thin sheets is manageable.

  8. Laser Cladding of Ultra-Thin Nickel-Based Superalloy Sheets

    Directory of Open Access Journals (Sweden)

    Tobias Gabriel

    2017-03-01

    Full Text Available Laser cladding is a well-established process to apply coatings on metals. However, on substrates considerably thinner than 1 mm it is only rarely described in the literature. In this work 200 µm thin sheets of nickel-based superalloy 718 are coated with a powder of a cobalt-based alloy, Co–28Cr–9W–1.5Si, by laser cladding. The process window is very narrow, therefore, a precisely controlled Yb fiber laser was used. To minimize the input of energy into the substrate, lines were deposited by setting single overlapping points. In a design of experiments (DoE study, the process parameters of laser power, laser spot area, step size, exposure time, and solidification time were varied and optimized by examining the clad width, weld penetration, and alloying depth. The microstructure of the samples was investigated by optical microscope (OM and scanning electron microscopy (SEM, combined with electron backscatter diffraction (EBSD and energy dispersive X-ray spectroscopy (EDX. Similarly to laser cladding of thicker substrates, the laser power shows the highest influence on the resulting clad. With a higher laser power, the clad width and alloying depth increase, and with a larger laser spot area the weld penetration decreases. If the process parameters are controlled precisely, laser cladding of such thin sheets is manageable.

  9. Material Flow and Oxide Particle Distributions in Friction-Stir Welded F/M-ODS Sheets

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Suk Hoon; Noh, Sanghoon; Jin, Hyun Ju; Kim, Tae Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    It is well known that uniform nano-oxide dispersoids act as pinning points to obstruct dislocation and grain boundary motion in ODS(Oxide dispersion strengthened) steel. However, these advantages will disappear while the material is subjected to the high temperature of conventional fusion welding. There is only limited literature available on the joining of ODS steels. Friction stir welding (FSW) is considered to be the best welding technique for welding ODS steels as the technique helps in retaining the homogeneous nano-oxide particles distributions in matrix. FSW is a solid.state, hot.shear joining process in which a rotating tool with a shoulder and terminating in a threaded pin, moves along the butting surfaces of two rigidly clamped plates placed on a backing plate. Heat generated by friction at the shoulder and to a lesser extent at the pin surface, softens the material being welded. Severe plastic deformation and flow of this plasticised metal occurs as the tool is translated along the welding direction. Material is transported from the front of the tool to the trailing edge where it is forged into a joint. Friction stir welding appears to be a very promising technique for the welding of FMS and ODS steels. This study found that, during FSW, the forward movement of the tool pin results in loose contact between the tool pin and the receding material on the advancing side.

  10. Microstructure Evolution of Electron Beam Physical Vapour Deposited Ni-23.5Cr-2.66Co-1.44Al Superalloy Sheet During Annealing at 600 °C

    Directory of Open Access Journals (Sweden)

    Li Mingwei

    2013-02-01

    Full Text Available Microstructure evolution of electron beam physical vapour deposited (EB-PVD Ni‑23.5Cr‑2.66Co‑1.44Al superalloy sheet during annealing at 600 °C was investigated. The results showed that the as-deposited alloy was composed of only g phase. After annealing at 600 °C, the locations of diffraction peaks were still the same. The (220 diffraction peak of the deposition side increased with annealing time. The sheet on deposited side had a tendency toward forming (220 texture during post-annealing. No obvious texture was observed at as-deposited and annealed sheet at 600 °C in substrate side. The count and size of "voids" decreased with time. The size of grains increased obviously with annealing time. The ultimate tensile strength of EB-PVD Ni-23.5Cr-2.66Co-1.44Al alloy sheet increased from 641 MPa to 829 MPa after annealing at 600 °C for 30 hours.

  11. High Velocity Oxidation and Hot Corrosion Resistance of Some ODS Alloys

    Science.gov (United States)

    Lowell, C. E.; Deadmore, D. L.

    1977-01-01

    Several oxide dispersion strengthened (ODS) alloys were tested for cyclic, high velocity, oxidation, and hot corrosion resistance. These results were compared to the resistance of an advanced, NiCrAl coated superalloy. An ODS FeCrAl were identified as having sufficient oxidation and hot corrosion resistance to allow potential use in an aircraft gas turbine without coating.

  12. Effect of TMP variables upon structure and properties in ODS alloy HDA 8077 sheet. [ThermoMechanical Processing of Oxide Dispersion Strengthened nickel alloy

    Science.gov (United States)

    Rothman, M. F.; Tawancy, H. M.

    1980-01-01

    The effects of oxide content level and variations in thermomechanical processing upon the final structure and properties of HDA 8077 sheet have been systematically examined. It was found that creep strength and formability are substantially influenced by both oxide content and TMP schedule. Variations in creep properties obtained appear to correlate with observed microstructures.

  13. Improved cyclic oxidation resistance of electron beam physical vapor deposited nano-oxide dispersed {beta}-NiAl coatings for Hf-containing superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Guo Hongbo [School of Materials Science and Engineering, Beihang University, No. 37, Xueyuan Road, Beijing 100191 (China); Beijing Key Laboratory for Advanced Functional Materials and Thin Film Technology, Beihang University, No. 37, Xueyuan Road, Beijing 100191 (China)], E-mail: Guo.hongbo@buaa.edu.cn; Cui Yongjing; Peng Hui; Gong Shengkai [School of Materials Science and Engineering, Beihang University, No. 37, Xueyuan Road, Beijing 100191 (China); Beijing Key Laboratory for Advanced Functional Materials and Thin Film Technology, Beihang University, No. 37, Xueyuan Road, Beijing 100191 (China)

    2010-04-15

    Oxide dispersed (OD) {beta}-NiAl coatings and OD-free {beta}-NiAl coatings were deposited onto a Hf-containing Ni-based superalloy by electron beam physical vapor deposition (EB-PVD). Excessive enrichment of Hf was found in the TGO on the OD-free coating due to outward diffusion of Hf from the superalloy, causing accelerated TGO thickening and spalling. The OD-coating effectively prevented Hf from outward diffusion. Only small amount of Hf diffused to the coating surface and improved the TGO adherence by virtue of the reactive element effect. The OD-coating exhibited an improved oxidation resistance as compared to the OD-free coating.

  14. Welding superalloy sheet for superconducting cable jackets

    International Nuclear Information System (INIS)

    Summers, L.T.; Strum, M.J.; Morris, J.W. Jr.

    1983-08-01

    Autogenous gas tungsten arc welds produced in A-286 exhibit significantly lower yield and ultimate tensile strengths than comparably heat-treated base metal. Deformation in the aged weld metal is highly localized and delineates the dendritic microstructure. The observed mechanical properties are caused by the formation of precipitate-free regions located at the dendrite cores. These regions form as the result of titanium segregation during weld pool solidification which yields dendrite cores sufficiently lean in titanium as to prevent nucleation of the hardening phase

  15. ODS iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Wright, I.G.; Pint, B.A.; Ohriner, E.K.; Tortorelli, P.F. [Oak Ridge National Lab., TN (United States)

    1996-08-01

    The overall goal of this program is to develop an oxide dispersion-strengthened (ODS) version of Fe{sub 3}Al that has sufficient creep strength and resistance to oxidation at temperatures in the range 1000 to 1200{degrees}C to be suitable for application as heat exchanger tubing in advanced power generation cycles. The program has two main thrusts: (a) alloy processing, which involves mechanical alloying and thermomechanical processing to achieve the desired size and distribution of the oxide dispersoid, and (b) optimization of the oxidation behavior to provide increased service life compared to ODS-FeCrAl alloys intended for the same applications. Control of the grain size and shape in the final alloy is very dependent on the homogeneity of the alloy powder, in terms of the size and distribution of the dispersed oxide particles, and on the level of strain and temperature applied in the recrystallization step. Studies of the effects of these variables are being made using mechanically-alloyed powder from two sources: a commercial powder metallurgy alloy vendor and an in-house, controlled environment high-energy mill. The effects of milling parameters on the microstructure and composition of the powder and consolidated alloy are described. Comparison of the oxidation kinetics of ODS-Fe{sub 3}Al alloys with commercial ODS-FeCrAl alloys in air at 1000-1300{degrees}C indicated that the best Fe{sub 3}Al-based alloys oxidized isothermally at the same rate as the ODS-FeCrAl alloys but, under thermal cycling conditions, the oxidation rate of ODS-Fe{sub 3}Al was faster. The main difference was that the ODS-Fe{sub 3}Al experienced significantly more scale spallation above 1000{degrees}C. The differences in oxidation behavior were translated into expected lifetimes which indicated that, for an alloy section thickness of 2.5 mm, the scale spallation of ODS-Fe{sub 3}Al leads to an expected service lifetime similar to that for the INCO alloy MA956 at 1100 to 1300{degrees}C.

  16. Electron-microscopic investigations of dispersion-strengthened superalloys

    International Nuclear Information System (INIS)

    Schroeder, J.H.; Arzt, E.

    1988-01-01

    Oxide dispersion strengthened (ODS) superalloys possess a high creep strength up to temperatures above 1000 0 C. This is due to a fine dispersion of incoherent Y 2 O 3 particles in connection with a highly elongated grain structure. To investigate the production and properties of ODS alloys, the grain structure was studied and the shape and distribution of dispersoids were characterized after each of the various production steps. Because the interactions between lattice dislocations and dispersoids control the deformation behaviour at high temperatures, the dislocation-dispersoid configurations in crept specimens have been studied by a TEM stereo technique and under weak-beam conditions. It was possible to detect strain fields around the dispersoids using TEM. The results lead to an improved understanding of dispersion strengthening at high temperatures and provide guidelines for the optimum use of this strengthening mechanism. (orig.) [de

  17. Introduction to superalloys

    International Nuclear Information System (INIS)

    Li-Chenggong

    1995-01-01

    Throughout history, humans have developed mechanical devices to satisfy their needs, Jet aircraft was thrust into public awareness with the 1937 flight of Hans Von Ohains turbine engine Heinkel in Germany and an independent development, the 1939 flight of Whittle's engine in England. Since that time, progress in jet propulsion and industrial gas turbines has been a growing engineering technology of immense importance. This opened a new era of engineering material called superalloy. Superalloy is an alloy developed for elevated temperature service usually based on group VIIA elements, where relatively severe mechanical stressing is encountered, and where high surface stability is frequently required. The title of the speech is T he Effect of a Changing Environment on the requirements of Engine Materials . In this speech, the author emphasized that may changes in the business environment have occurred in recent years, the aircraft engine business is rapidly changing from a military focus to a commercial one, speed to market will assume greater importance in the engine industry, and greater attention to customer value will be required to remain competitive etc. However the superalloys will continue to be developed in the future. (author) 14 figs

  18. Creep and residual mechanical properties of cast superalloys and oxide dispersion strengthened alloys

    Science.gov (United States)

    Whittenberger, J. D.

    1981-01-01

    Tensile, stress-rupture, creep, and residual tensile properties after creep testing were determined for two typical cast superalloys and four advanced oxide dispersion strengthened (ODS) alloys. The superalloys examined included the nickel-base alloy B-1900 and the cobalt-base alloy MAR-M509. The nickel-base ODS MA-757 (Ni-16CR-4Al-0.6Y2O3 and the iron-base ODS alloy MA-956 (Fe-20Cr-5Al-0.8Y2O3) were extensively studied, while limited testing was conducted on the ODS nickel-base alloys STCA (Ni-16Cr-4.5Al-2Y2O3) with a without Ta and YD-NiCrAl (Ni-16Cr-5Al-2Y2O3). Elevated temperature testing was conducted from 114 to 1477 K except for STCA and YD-NiCrAl alloys, which were only tested at 1366 K. The residual tensile properties of B-1900 and MAR-M509 are not reduced by prior creep testing (strains at least up to 1 percent), while the room temperature tensile properties of ODS nickel-base alloys can be reduced by small amounts of prior creep strain (less than 0.5 percent). The iron-base ODS alloy MA-956 does not appear to be susceptible to creep degradation at least up to strains of about 0.25 percent. However, MA-956 exhibits unusual creep behavior which apparently involves crack nucleation and growth.

  19. Rapidly cast crystalline thin sheet materials

    International Nuclear Information System (INIS)

    Warlimont, H.; Emmerich, K.

    1986-01-01

    The current state and progress of casting thin sheet and ribbons directly from the melt are reviewed. First, the solidification phenomena pertinent to the process are outlined. Subsequently, Fe-Si,l Fe-Si-Al, Fe-Nd-B, Ag-Cu-Ti, alloy steels, Ni superalloys and Si are treated as examples. Finally, the information available on process development is critically assessed

  20. Refractory metal based superalloys

    International Nuclear Information System (INIS)

    Alonso, Paula R.; Vicente, Eduardo E.; Rubiolo, Gerardo H.

    1999-01-01

    Refractory metals are looked as promising materials for primary circuits in fission reactors and even as fusion reactor components. Indeed, superalloys could be developed which take advantage of their high temperature properties together with the benefits of a two- phase (intermetallic compound-refractory metal matrix) coherent structure. In 1993, researchers of the Office National d'Etudes et de Recherches Aerospatiales of France reported the observation of such a coherent structure in the Ta-Ti-Zr-Al-Nb-Mo system although the exact composition is not reported. The intermetallic compound would be Ti 2 AlMo based. However, the formation of this compound and its possible coexistence with a disordered bcc phase in the ternary system Ti-Al-Mo is a controversial subject in the related literature. In this work we develop a technique to obtain homogeneous alloys samples with 50 Ti-25 Al-25 Mo composition. The resulting specimens were characterized by optical and electronic metallography (SEM), microprobe composition measurements (EPMA) and X-ray diffraction (XRD) analyses. The results show the evidence for a bcc (A2→B2) ordering reaction in the Ti-Al-Mo system in the 50 Ti-25 Al-25 Mo composition. (author)

  1. Mechanical behavior of superalloys

    International Nuclear Information System (INIS)

    Floreen, S.

    1986-04-01

    Recent developments affecting the mechanical behavior of superalloys over three ranges of operating temperatures are reviewed. At lower temperatures, activity has been focused on stress corrosion cracking susceptibility in light water reactor and sour gas well environments. The susceptibility to intergranular crack growth is critically dependent upon the grain boundary chemistry, and a method of minimizing the sensitivity of the boundaries to attack has been pursued. At intermediate temperatures, considerable effort has been directed toward increasing the tensile and fatigue strengths. The higher strength materials, however, show increased fracture sensitivity. In particular, embrittlement due to diffusion into the grain boundaries of aggressive species, such as oxygen or sulfur from the environments, becomes a problem. Minor element alloying additions of boron, zirconium, magnesium, etc., are helpful in retarding the degradation caused by the environment. At higher temperatures, the major thrust is toward improving the creep strength. The weak link in the materials, which is the transverse grain boundaries, has been eliminated by the use of specialized processing steps to produce either directionally solidified materials with minimum transverse grain boundaries, or single crystal materials. Single crystal materials permit alloying and heat treating modifications that further enhance the creep strength. The materials are very anisotropic in properties, but are successfully used in turbine blades and could be useful in other special applications

  2. Ozone-depleting Substances (ODS)

    Data.gov (United States)

    U.S. Environmental Protection Agency — This site includes all of the ozone-depleting substances (ODS) recognized by the Montreal Protocol. The data include ozone depletion potentials (ODP), global warming...

  3. Expert systems for superalloy studies

    Science.gov (United States)

    Workman, Gary L.; Kaukler, William F.

    1990-01-01

    There are many areas in science and engineering which require knowledge of an extremely complex foundation of experimental results in order to design methodologies for developing new materials or products. Superalloys are an area which fit well into this discussion in the sense that they are complex combinations of elements which exhibit certain characteristics. Obviously the use of superalloys in high performance, high temperature systems such as the Space Shuttle Main Engine is of interest to NASA. The superalloy manufacturing process is complex and the implementation of an expert system within the design process requires some thought as to how and where it should be implemented. A major motivation is to develop a methodology to assist metallurgists in the design of superalloy materials using current expert systems technology. Hydrogen embrittlement is disasterous to rocket engines and the heuristics can be very complex. Attacking this problem as one module in the overall design process represents a significant step forward. In order to describe the objectives of the first phase implementation, the expert system was designated Hydrogen Environment Embrittlement Expert System (HEEES).

  4. Fatigue of superalloys and intermetallics

    International Nuclear Information System (INIS)

    Stoloff, N.S.

    1993-01-01

    The fatigue behavior of intermetallic alloys and their composites is contrasted to that of nickel-base superalloys. The roles of microstructure and slip planarity are emphasized. Obstacles to use of intermetallics under cyclic loading conditions are described and future research directions are suggested

  5. Od psihoterapije do utopije

    Directory of Open Access Journals (Sweden)

    Josip Ćirić

    2015-06-01

    -metodu, Milgram (Obedience to Authority 30-31 skupio je procjene stručnjaka i nestručnjaka o očekivanu ponašanju ispitanika i one su pokazale zapanjujuću razliku naspram empirijskih ishoda – procijenjeno je da će 0,1% ispitanika elektrošokove zadavati do kraja, dok su ispitivanja pokazala da taj postotak raste do 65% (33. Logički biheviorizam u filozofiji znanosti, problem odnosa um-tijelo (za detaljnu sistematizaciju logičkog prostora ovog problema vidi Ludwig 10-11 ili pitanja vezana uz umjetnu inteligenciju u filozofiji uma samo su neke od ilustracija utjecaja filozofskih teorija na psihologiju. Fokus je našeg istraživanja na politikama koje proizlaze iz psihoterapijske teorije i prelaženju granica koje postavlja znanstveni diskurs.

  6. Soft Computing Methods in Design of Superalloys

    Science.gov (United States)

    Cios, K. J.; Berke, L.; Vary, A.; Sharma, S.

    1996-01-01

    Soft computing techniques of neural networks and genetic algorithms are used in the design of superalloys. The cyclic oxidation attack parameter K(sub a), generated from tests at NASA Lewis Research Center, is modelled as a function of the superalloy chemistry and test temperature using a neural network. This model is then used in conjunction with a genetic algorithm to obtain an optimized superalloy composition resulting in low K(sub a) values.

  7. ODS Alloys for Nuclear Applications

    International Nuclear Information System (INIS)

    Jang, Jin Sung

    2006-01-01

    ODS (oxide dispersion strengthening) alloy is one of the potential candidate alloys for the cladding or in reactor components of Generation IV reactors and for the structural material even for fusion reactors. It is widely accepted as very resistant material to neutron irradiation as well as strong material at high temperature due to its finely distributed and stable oxide particles. Among Generation IV reactors SFR and SCWR are anticipated in general to run in the temperature range between 300 and 550 .deg. C, and the peak cladding temperature is supposed to reach at about 620 .deg. C during the normal operation. Therefore Zr.base alloys, which have been widely known and adopted for the cladding material due to their excellent neutron economics, are no more adequate at these operating conditions. Fe-base ODS alloys in general has a good high temperature strength at the above high temperature as well as the neutron resistance. In this study a range of commercial grade ODS alloys and their applications are reviewed, including an investigation of the stability of a commercial grade 20% Cr Fe-base ODS alloy(MA956). The alloy was evaluated in terms of the fracture toughness change along with the aging treatment. Also an attempt of the development of 9% Cr Fe-base ODS alloys is introduced

  8. Superalloy Lattice Block Developed for Use in Lightweight, High-Temperature Structures

    Science.gov (United States)

    Hebsur, Mohan G.; Whittenberger, J. Daniel; Krause, David L.

    2003-01-01

    Successful development of advanced gas turbine engines for aircraft will require lightweight, high-temperature components. Currently titanium-aluminum- (TiAl) based alloys are envisioned for such applications because of their lower density (4 g/cm3) in comparison to superalloys (8.5 g/cm3), which have been utilized for hot turbine engine parts for over 50 years. However, a recently developed concept (lattice block) by JAMCORP, Inc., of Willmington, Massachusetts, would allow lightweight, high-temperature structures to be directly fabricated from superalloys and, thus, take advantage of their well-known, characterized properties. In its simplest state, lattice block is composed of thin ligaments arranged in a three dimensional triangulated trusslike configuration that forms a structurally rigid panel. Because lattice block can be fabricated by casting, correctly sized hardware is produced with little or no machining; thus very low cost manufacturing is possible. Together, the NASA Glenn Research Center and JAMCORP have extended their lattice block methodology for lower melting materials, such as Al alloys, to demonstrate that investment casting of superalloy lattice block is possible. This effort required advances in lattice block pattern design and assembly, higher temperature mold materials and mold fabrication technology, and foundry practice suitable for superalloys (ref. 1). Lattice block panels have been cast from two different Ni-base superalloys: IN 718, which is the most commonly utilized superalloy and retains its strength up to 650 C; and MAR M247, which possesses excellent mechanical properties to at least 1100 C. In addition to the open-cell lattice block geometry, same-sized lattice block panels containing a thin (1-mm-thick) solid face on one side have also been cast from both superalloys. The elevated-temperature mechanical properties of the open cell and face-sheeted superalloy lattice block panels are currently being examined, and the

  9. High temperature oxidation behavior of ODS steels

    Science.gov (United States)

    Kaito, T.; Narita, T.; Ukai, S.; Matsuda, Y.

    2004-08-01

    Oxide dispersion strengthened (ODS) steels are being developing for application as advanced fast reactor cladding and fusion blanket materials, in order to allow increased operation temperature. Oxidation testing of ODS steel was conducted under a controlled dry air atmosphere to evaluate the high temperature oxidation behavior. This showed that 9Cr-ODS martensitic steels and 12Cr-ODS ferritic steels have superior high temperature oxidation resistance compared to 11 mass% Cr PNC-FMS and 17 mass% Cr ferritic stainless steel. This high temperature resistance is attributed to earlier formation of the protective α-Cr 2O 3 on the outer surface of ODS steels.

  10. Friction Stir Processing of ODS and FM Steels

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Suk Hoon; Chun, Young Bum; Noh, Sang Hoon; Jang, Jin Sung; Kim, Tae Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    In ODS steels, it is well known that uniform nano-oxide dispersoids act as pinning points to obstruct dislocation and grain boundary motion, however, those advantages will be disappeared while the material is subjected to the high temperature of conventional fusion welding. Rotary friction welding, also referred to as friction stir welding (FSW), has shown great promise as a method for welding traditionally difficult to weld materials such as aluminum alloys. This relatively new technology has more recently been applied to higher melting temperature alloys such as steels, nickel-based and titanium alloys. Friction stir processing (FSP) is a method of changing the properties of a metal through intense, localized plastic deformation. FSW is the precursor of the FSP technique. When ideally implemented, this process mixes the material without changing the phase and creates a microstructure with fine, equiaxed grains. This homogeneous grain structure, separated by high-angle boundaries, allows some alloys to take on superplastic properties. In this study, FSW is used as a substitutive welding process between FMS tube and ODS parts. The dimension of tube is 7.0 OD, 0.5 T. During the FSW, dynamic-recrystallized grains are developed; the uniform oxides dispersion is preserved in the metal matrix. The microstructure and microtexture of the material near the stir zone is found to be influenced by the rotational behavior of the tool. The additive effect from FSP on sample surface is considered. Since the mechanical alloying (MA) and FSP commonly apply extreme shear deformation on materials, the dispersion of oxide particle in ODS steels is very active during both processes. Friction stir welding appears to be a very promising technique for the welding of FMS and ODS steels in the form of sheet and tube. FSW could successfully produce defect-free welds on FMS tubes and ODS ring assembly. FSW produces a fine grain structure consisting of ferrite and martensite, and the oxide

  11. Friction Stir Processing of ODS and FM Steels

    International Nuclear Information System (INIS)

    Kang, Suk Hoon; Chun, Young Bum; Noh, Sang Hoon; Jang, Jin Sung; Kim, Tae Kyu

    2013-01-01

    In ODS steels, it is well known that uniform nano-oxide dispersoids act as pinning points to obstruct dislocation and grain boundary motion, however, those advantages will be disappeared while the material is subjected to the high temperature of conventional fusion welding. Rotary friction welding, also referred to as friction stir welding (FSW), has shown great promise as a method for welding traditionally difficult to weld materials such as aluminum alloys. This relatively new technology has more recently been applied to higher melting temperature alloys such as steels, nickel-based and titanium alloys. Friction stir processing (FSP) is a method of changing the properties of a metal through intense, localized plastic deformation. FSW is the precursor of the FSP technique. When ideally implemented, this process mixes the material without changing the phase and creates a microstructure with fine, equiaxed grains. This homogeneous grain structure, separated by high-angle boundaries, allows some alloys to take on superplastic properties. In this study, FSW is used as a substitutive welding process between FMS tube and ODS parts. The dimension of tube is 7.0 OD, 0.5 T. During the FSW, dynamic-recrystallized grains are developed; the uniform oxides dispersion is preserved in the metal matrix. The microstructure and microtexture of the material near the stir zone is found to be influenced by the rotational behavior of the tool. The additive effect from FSP on sample surface is considered. Since the mechanical alloying (MA) and FSP commonly apply extreme shear deformation on materials, the dispersion of oxide particle in ODS steels is very active during both processes. Friction stir welding appears to be a very promising technique for the welding of FMS and ODS steels in the form of sheet and tube. FSW could successfully produce defect-free welds on FMS tubes and ODS ring assembly. FSW produces a fine grain structure consisting of ferrite and martensite, and the oxide

  12. Superalloy applications in the nuclear field

    International Nuclear Information System (INIS)

    Ramanathan, L.V.; Padilha, A.F.

    1984-01-01

    The process conditions in the areas of nuclear fuel processing, fabrication, utilization, reprocessing and disposal are severe, demanding therefore the use of materials with high temperature mechanical strength and corrosion resistance. A number of refractory metal containing superalloys have found application in the diferrent areas of the nuclear field. The main aspects of the microstructure, strengthening mechanisms and corrosion resistance of 3 superalloys, namely Incoloy 825, Inconel 718 and Hastelloy C have been discussed. The role of the refractory metal elements in influencing the mechanical strength and corrosion resistance of superalloys has been emphasised. (Author) [pt

  13. Fiber laser welding of nickel based superalloy Inconel 625

    Science.gov (United States)

    Janicki, Damian M.

    2013-01-01

    The paper describes the application of single mode high power fiber laser (HPFL) for the welding of nickel based superalloy Inconel 625. Butt joints of Inconel 625 sheets 0,8 mm thick were laser welded without an additional material. The influence of laser welding parameters on weld quality and mechanical properties of test joints was studied. The quality and mechanical properties of the joints were determined by means of tensile and bending tests, and micro hardness tests, and also metallographic examinations. The results showed that a proper selection of laser welding parameters provides non-porous, fully-penetrated welds with the aspect ratio up to 2.0. The minimum heat input required to achieve full penetration butt welded joints with no defect was found to be 6 J/mm. The yield strength and ultimate tensile strength of the joints are essentially equivalent to that for the base material.

  14. The metallurgy of superalloys part 2

    International Nuclear Information System (INIS)

    Abdelazim, M.E.; Hammad, F.H.

    1990-01-01

    This is part II of the report titled 'the metallurgy of superalloys'. It deals with the effect of heat treatment and operating conditions (thermal exposure and environment) on the mechanical properties of superalloys. The heat treatment is important in the development of superalloys through that it controls type, amount, size shape and distribution of the precipitate and the grain size of the matrix. The thermal exposure leads to reduction in the amount of the primary carbides and to precipitation of secondary carbides. Also it leads to the agglomeration and coarsening of gamma or the transformation of gamma phase to phase. The environment may lead to the internal oxidation, carburization, decarburization or sulphidization of the superalloys which may result in the degradation of their mechanical properties. This part gives also an example of applications of superalloys in the field of nuclear reactors especially high temperature-gas cooled reactors. Joined with this part a table which contains the major superalloys including its chemical analysis, creep rupture strength and some of its applications. 1 tab

  15. The metallurgy of superalloys part 1

    International Nuclear Information System (INIS)

    Abdelazim, M.E.; Hammad, F.H.

    1990-01-01

    This is part I of the report titled 'the metallurgy of superalloys'. In this part the structure, phases and systems of superalloys are reviewed. The role of alloying elements in the design of superalloys and the mechanical properties of superalloys are also reviewed. Superalloys are important in high temperature technology, especially above 700 degree c. They are 'super' mainly because their creep and stress rupture resistances are very high. Superalloys are based on an austenitic matrix including secondary phases, mainly gamma precipitates, inter and intragranular carbides mainly M 23 C 6 and M 6 C. They are classified into three systems, Ni-base, Fe-Ni base and Ce-base alloys. Different alloying elements mainly Cr, Mo, Al, Ti are added to increase the strength either by solid solution hardening (Cr, Mo, Al), precipitation hardening (A 1, Ti to produce gamma) or by dispersion hardening (Cr, Mo to form M 23 C 6 and M 6 C carbides) and to increase the oxidation resistance (Cr, Al). 3 tab., 2 fig

  16. The Knossos Od Series. An Epigraphical Study

    DEFF Research Database (Denmark)

    Nosch, Marie-Louise Bech

    This study is an epigraphical investigation of the Linear B records from the West Wing in the palace of Knossos. Its focus is the group of 61 unclassified Od tablets with the ideogram for wool. The author presents a new classification of the Od tablets by identifying new sets, and by integrating...... unclassified Od tablets into existing Od sets or into other series recording wool, such as the two well known and thoroughly researched "bureaux", the textile and the sheep administration. Recent work by FIRTH on find-places has provided new insights for this study. In the present study, 29 prefix changes...... are suggested. Only few unclassified Od tablets, however, can be associated with the initial parts of textile production in which scribes 103 and 113 set targets and manage the production. Rather, many unclassified Od tablets belong to the final stages of the textile production, that is, the finishing...

  17. ZASEBNOST OD RABE DO ZLORABE

    OpenAIRE

    Flegerič, Tamara

    2012-01-01

    Nastanek interneta in njegova popularizacija s pojavom svetovnega spleta je povzročil veliko revolucijo. Najpopularnejše orodje spleta 2.0 in s tem najpomembnejši medij spletne komunikacije so postala spletna socialna omrežja. Spletno socialno omrežje, ki je postalo pravi fenomen in kateremu smo se posvetili v pričujoči diplomski nalogi, je Facebook. V diplomskem delu z naslovom »Zasebnost od rabe do zlorabe« sta predstavljeni zasebnost in varnost na Facebooku. V teoretičnem delu se bomo posv...

  18. The oxidation and corrosion of ODS alloys

    Science.gov (United States)

    Lowell, Carl E.; Barrett, Charles A.

    1990-01-01

    The oxidation and hot corrosion of high temperature oxide dispersion strengthened (ODS) alloys are reviewed. The environmental resistance of such alloys are classified by oxide growth rate, oxide volatility, oxide spalling, and hot corrosion limitations. Also discussed are environmentally resistant coatings for ODS materials. It is concluded that ODS NiCrAl and FeCrAl alloys are highly oxidation and corrosion resistant and can probably be used uncoated.

  19. Oxidation And Hot Corrosion Of ODS Alloy

    Science.gov (United States)

    Lowell, Carl E.; Barrett, Charles A.

    1993-01-01

    Report reviews oxidation and hot corrosion of oxide-dispersion-strengthened (ODS) alloys, intended for use at high temperatures. Classifies environmental resistances of such alloys by rates of growth of oxides, volatilities of oxides, spalling of oxides, and limitations imposed by hot corrosion. Also discusses environmentally resistant coatings for ODS materials. Concludes ODS NICrAl and FeCrAl alloys highly resistant to oxidation and corrosion and can be used uncoated.

  20. Characterization of the ODS MA 956 superalloy for biomedical surgical implants

    International Nuclear Information System (INIS)

    Escudero, M.L.; Ruiz, J.; Gonzalez-Carrasco, J.L.; Chao, J.; Lopez, M.F.; Garcia-Alonso, M.C.; Canahua, H.; Adeva, P.; Coedo, A.G.; Dorado, M.T.; Rubio, J.C.; Martinez, M.E.; Munuera, L.; Agustin, D. de; Ruiz, J.

    1998-01-01

    Since the MA 956 was proposed as a possible new biomaterial due to its good corrosion resistance values in physiological fluids a long way, still not finished, has been done. An exhaustive characterization of this alloy at room temperature has been developed. The technological objectives are well established: the possible use of this material for biomedical as hip or knee prostheses and as dental implants. The study was performed comparing the results of this alloy with the materials used nowadays as surgical implants, i.e., titanium alloys and polyethylene. (Author) 5 refs

  1. Initial Development in Joining of ODS Alloys Using Friction Stir Welding

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Weiju [ORNL; Feng, Zhili [ORNL

    2007-08-01

    Solid-state welding of oxide-dispersion-strengthened (ODS) alloy MA956 sheets using friction stir welding (FSW) was investigated. Butt weld was successfully produced. The weld and base metals were characterized using optical microscopy, scanning electronic microscopy, transmission electronic microscopy, and energy dispersion x-ray spectrum. Microhardness mapping was also conducted over the weld region. Analyses indicate that the distribution of the strengthening oxides was preserved in the weld. Decrease in microhardness of the weld was observed but was insignificant. The preliminary results seem to confirm the envisioned feasibility of FSW application to ODS alloy joining. For application to Gen IV nuclear reactor heat exchanger, further investigation is suggested.

  2. Influence of the fabrication process parameters on microstructures and mechanical properties of 10Cr-1Mo ODS steel

    International Nuclear Information System (INIS)

    Jin, Hyun Ju; Kim, Ki Baik; Choi, Byoung Kwon; Kang, Suk Hoon; Noh, Sang Hoon; Kim, Ga Eon; Kim, Tae Kyu

    2016-01-01

    Oxide dispersion strengthened (ODS) FM steels have been developed as the most promising core structural material for high- temperature components operating in severe environments such as nuclear fusion and fission systems owing to its excellent elevated temperature strength and radiation resistance stemming from the addition of extremely thermally stable oxide particles dispersed in a ferritic/martensitic matrix. To realize the structural components such as plates, sheets and tubes in SFR, the development of manufacturing processes is an essential issue for the ODS FM steel. While the ODS steel has superior radiation resistance and high temperature strength, in comparison with the existing commercial steels, it is difficult for the ODS steel to obtain sufficient workability for the fabrication due to high hardness and low ductility at room temperature, meaning that the manufacturing of the ODS plate including cladding tube can be complicated by the low cold workability. In order to prevent the ODS steel from any damage during the manufacturing process, thus, the introduction of intermediate heat treatments between cold rolling processes is necessary. This study investigates effects of the fabrication process parameters such as the cold working ratio, the intermediate and final heat treatments on the microstructure and mechanical properties of 10Cr-1Mo ODS steel. In an effort to optimize the manufacturing route of the ODS FM steel, the microstructural and mechanical evolutions for the ODS plate manufactured by a control of the fabrication process parameters were evaluated in the present study. In the present study, the effect of a cold rolling and intermediate heat treatments on microstructures and mechanical properties of 10Cr-1Mo FM ODS steel were investigated. During the manufacturing route the hardness measurements remained below the critical value of 400 Hv. Intermediate heat treatment with slow cooling led to a softened ferritic structures which can be further

  3. Initial Mechanical Testing of Superalloy Lattice Block Structures Conducted

    Science.gov (United States)

    Krause, David L.; Whittenberger, J. Daniel

    2002-01-01

    The first mechanical tests of superalloy lattice block structures produced promising results for this exciting new lightweight material system. The testing was performed in-house at NASA Glenn Research Center's Structural Benchmark Test Facility, where small subelement-sized compression and beam specimens were loaded to observe elastic and plastic behavior, component strength levels, and fatigue resistance for hundreds of thousands of load cycles. Current lattice block construction produces a flat panel composed of thin ligaments arranged in a three-dimensional triangulated trusslike structure. Investment casting of lattice block panels has been developed and greatly expands opportunities for using this unique architecture in today's high-performance structures. In addition, advances made in NASA's Ultra-Efficient Engine Technology Program have extended the lattice block concept to superalloy materials. After a series of casting iterations, the nickel-based superalloy Inconel 718 (IN 718, Inco Alloys International, Inc., Huntington, WV) was successfully cast into lattice block panels; this combination offers light weight combined with high strength, high stiffness, and elevated-temperature durability. For tests to evaluate casting quality and configuration merit, small structural compression and bend test specimens were machined from the 5- by 12- by 0.5-in. panels. Linear elastic finite element analyses were completed for several specimen layouts to predict material stresses and deflections under proposed test conditions. The structural specimens were then subjected to room-temperature static and cyclic loads in Glenn's Life Prediction Branch's material test machine. Surprisingly, the test results exceeded analytical predictions: plastic strains greater than 5 percent were obtained, and fatigue lives did not depreciate relative to the base material. These assets were due to the formation of plastic hinges and the redundancies inherent in lattice block construction

  4. Forging Oxide-Dispersion-Strengthened Superalloys

    Science.gov (United States)

    Harf, F. H.; Glasgow, T. K.; Moracz, D. J.; Austin, C. M.

    1986-01-01

    Cladding of mild steel prevents surface cracking when alloy contacts die. Continual need for improvements in properties of alloys capable of withstanding elevated temperatures. Accomplished by using oxide-dispersion-strengthed superalloys such as Inconel Alloy MA 6000. Elevated tensile properties of forged alloy equal those of hot-rolled MA 6000 bar. Stress-rupture properties somewhat lower than those of bar stock but, at 1,100 degrees C, exceed those of strongest commercial single crystal, directionally solidified and conventionally cast superalloys.

  5. Microstructural evolution in friction stir welding of nanostructured ODS alloys

    International Nuclear Information System (INIS)

    Chen, C.-L.; Tatlock, G.J.; Jones, A.R.

    2010-01-01

    Nanostructured oxide dispersion strengthened (ODS) Fe-based alloys manufactured by mechanical alloying (MA) are generally considered to be promising candidate materials for high-temperature applications up to at least 1100 o C because of their excellent creep strength and good oxidation resistance. However, a key issue with these alloys is the difficulty in using fusion welding techniques to join components due to oxide particle agglomeration and loss in the weld zone and the disruption and discontinuity in the grain structure introduced at the bond. In this study, the evolution of microstructure has been comprehensively studied in friction stir welds in a ferritic ODS alloy. Initially, electron backscattering diffraction (EBSD) was used to analyze the grain orientation, the grain boundary geometries and recrystallization behaviour. It suggested that deformation heterogeneities were introduced during the friction stirring process which facilitated the onset of recrystallization. Transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) were used to observe the effects of the friction stir welding (FSW) process on the grain structure and the distribution of Y 2 O 3 and other particles in the metal substrates in the FSW and adjacent regions, after the alloys had been recrystallized at temperatures up to 1380 o C for 1 h in air. The results show that fine-equiaxed grains and a uniform distribution of oxide particles were present in the friction stirred region but that the grain boundaries in the parent metal were pinned by particles. Friction stirring appeared to release these boundaries and allowed secondary recrystallization to occur after further heat treatment. The FSW process appears to be a promising technique for joining ferritic ODS alloys in the form of sheet and tube.

  6. Fatigue studies of superalloys in Japan

    International Nuclear Information System (INIS)

    Kitagawa, Masaki

    1985-01-01

    In the past 15 years, several national projects were advanced to develop high temperature machinery, such as high temperature gas-cooled reactors, gas turbines and fusion reactors. Before, the studies on the strength of superalloys were rarely carried out, however, by the above research works, superalloys are in rapid progress. Because these machinery are subjected to temperature cycles and vibration stress, the fatigue failure is the main concern in the safety analysis of the components. The purpose of this paper is to summarize the present status of the fatigue research on the alloys for high temperature use in Japan. The superalloys used for gas turbine and HTGR components are listed, and the materials tested were mostly the alloys of nickel base, cobalt base or iron base. In the above national projects, the main purpose was to clarify the high temperature properties including fatigue properties, to develop the method of forecasting the life span and to develop better materials. As the topics about the fatigue research on superalloys, the development of the method for forecasting the life span, the effect of directional solidification, coating and HIP process on the fatigue strength of gas turbine materials, the effect of helium and aging on the fatigue strength of HTGR materials, the fatigue strength of weldment of HTGR materials and others are reported. (Kako, I.)

  7. Chemical driving force for rafting in superalloys

    CSIR Research Space (South Africa)

    Nabarro, FRN

    1997-08-15

    Full Text Available The author provides a brief overview of the chemical driving forces for rafting in superalloys. Until recently, all theories of the driving force for rafting have considered the compositions of the two phases to be fixed, although accepting...

  8. Fatigue properties of MA 6000E, a gamma-prime strengthened ODS alloy. [Oxide Dispersion Strengthened Ni-base alloy for gas turbine blade applications

    Science.gov (United States)

    Kim, Y. G.; Merrick, H. F.

    1980-01-01

    MA 6000E is a corrosion resistant, gamma-prime strengthened ODS alloy under development for advanced turbine blade applications. The high temperature, 1093 C, rupture strength is superior to conventional nickel-base alloys. This paper addresses the fatigue behavior of the alloy. Excellent properties are exhibited in low and high cycle fatigue and also thermal fatigue. This is attributed to a unique combination of microstructural features, i.e., a fine distribution of dispersed oxides and other nonmetallics, and the highly elongated grain structure which advantageously modify the deformation characteristics and crack initiation and propagation modes from that characteristic of conventional gamma-prime hardened superalloys.

  9. Decontamination sheet

    International Nuclear Information System (INIS)

    Hirose, Emiko; Kanesaki, Ken.

    1995-01-01

    The decontamination sheet of the present invention is formed by applying an adhesive on one surface of a polymer sheet and releasably appending a plurality of curing sheets. In addition, perforated lines are formed on the sheet, and a decontaminating agent is incorporated in the adhesive. This can reduce the number of curing operation steps when a plurality steps of operations for radiation decontamination equipments are performed, and further, the amount of wastes of the cured sheets, and operator's exposure are reduced, as well as an efficiency of the curing operation can be improved, and propagation of contamination can be prevented. (T.M.)

  10. Reduction in Defect Content in ODS Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ritherdon, J.; Jones, A.R.

    2000-02-01

    The work detailed within this report is a continuation of earlier work that was carried out under contract number IDX-SY382V. The earlier work comprised a literature review of the sources and types of defects found principally in Fe-based ODS alloys together with a series of experiments designed to identify defects in ODS Fe{sub 3}Al material and recommend methods of defect reduction. Defects found in the Mechanically Alloyed (MA) ODS Fe{sub 3}Al included regions of incomplete MA, porosity, intrusions and fine-grained stringers. Some defects tended to be found in association with one another e.g. intrusions and fine-grained stringers. Preliminary powder separation experiments were also performed. The scope and objectives of the present work were laid out in the technical proposal ``Reduction in Defect Content in ODS Alloys--II'' which formed the basis of amendment 3 of the current contract. The current studies were devised in the context of the preceding work with a view to extending and concluding certain experiments while exploring new avenues of investigation of defect control and reduction where appropriate. All work proposed was within the context of achieving an ODS Fe{sub 3}Al alloy of improved overall quality and potential creep performance (particularly) in the consolidated, release condition. The interim outturn of the experimental work performed is also reported.

  11. ODS alloys for structures subjected to irradiation

    International Nuclear Information System (INIS)

    Carlan, Y. de

    2010-01-01

    ODS (oxide-dispersion-strengthened) materials are considered for cladding purposes for the fourth-generation sodium-cooled fast reactors. ODS materials afford many benefits. Indeed, these high-performance materials combine, at the same time, remarkable mechanical strength, in hot conditions, and outstanding irradiation behavior. New ODS steel grades, exhibiting better performance levels than the last-generation austenitic steels, afford not only negligible swelling under irradiation, owing to their 'ferritic' body-centered cubic structure - by contrast to austenitic grades, which feature a face-centered cubic structure - but equally outstanding creep properties, owing to the nano-reinforcements present in the matrix. ODS materials are obtained by powder metallurgy, the first fabrication step involves co-grinding a metal powder together with yttrium oxide (Y 2 O 3 ) powder. At this stage, an iron oxide may also be added, or an yttrium-rich intermetallic compound in order to provide the amounts of yttrium, and oxygen required for the formation of nano-oxides. The metal powder consists of a powder pre-alloyed to the chemical composition of the desired material. Once the powder has been obtained, consolidation of the ODS materials is achieved either by hot extrusion, or by hot isostatic pressing. (A.C.)

  12. Superalloy applications in the fast breeder reactor

    International Nuclear Information System (INIS)

    Powell, R.W.

    1976-01-01

    The economics of the LMFBR are dependent on the breeding of new fuel in the reactor core and this can be improved by the use of advanced alloys as core structural components. The environment of the core makes superalloys a natural choice for these components, but phenomena related directly to neutron irradiation necessitate extensive testing. Consequently, commercially-available superalloys, together with a number of developmental alloys are being tested in existing LMFBR's and by simulation techniques to determine the best alloy for use in the LMFBR core. It presently appears that such materials will indeed be capable of the performance required, and will greatly facilitate the commercial realization of the fast breeder reactor

  13. Development of Wrought Superalloy in China

    Directory of Open Access Journals (Sweden)

    DU Jinhui

    2016-06-01

    Full Text Available Wrought superalloy development in China was reviewed in recent ten years. The achievement of basic research and development of industrial manufacture technologies were systematically described from the aspects of new alloys, new technologies of hot deformation. New alloys include: new disc materials 718Plus, GH4720Li and GH4065 alloy, combustion chamber alloy GH3230, and GH4706 alloy for gas turbine engines. New technologies include: ERS-CDS new technology of easy segregation materials, multi upsetting-drawing for improving the microstructure uniformity of bars, slow cooling and multi-cycle thermomechanical treatment for increasing hot plasticity of hard-to-work alloys. Finally, the further development of wrought superalloys was prospected.

  14. Effects of helium impurities on superalloys

    International Nuclear Information System (INIS)

    Selle, J.E.

    1977-07-01

    A review of the literature on the effects of helium impurities on superalloys at elevated temperatures was undertaken. The actual effects of these impurities vary depending on the alloy, composition of the gas atmosphere, and temperature. In general, exposure in helium produces significant but not catastrophic changes in the structure and properties of the alloys. The effects of these treatments on the structure, creep, fatigue, and mechanical properties of the various alloys are reviewed and discussed. Suggestions for future work are presented

  15. The BGO-OD experiment. Status

    Energy Technology Data Exchange (ETDEWEB)

    Hannappel, Juergen [Physikalisches Institut der Universitaet Bonn (Germany); Collaboration: BGO-OD-Collaboration

    2015-07-01

    In the framework of an international collaboration a new detector is set up at the accelerator facility ELSA in Bonn, the BGO-OD experiment. It aims at systematic investigation of nonstrange and strange meson photoproduction, in particular t-channel processes at low momentum transfer. The setup uniquely combines a central almost 4π acceptance BGO crystal calorimeter with a large aperture forward magnetic spectrometer providing good detection of both neutral and charged particles, complementary to other setups like CB, LEPS or CLAS. An overview of the BGO-OD detector is presented. Preliminary data from the first data takings will be shown and discussed.

  16. A handbook of statistical graphics using SAS ODS

    CERN Document Server

    Der, Geoff

    2014-01-01

    An Introduction to Graphics: Good Graphics, Bad Graphics, Catastrophic Graphics and Statistical GraphicsThe Challenger DisasterGraphical DisplaysA Little History and Some Early Graphical DisplaysGraphical DeceptionAn Introduction to ODS GraphicsGenerating ODS GraphsODS DestinationsStatistical Graphics ProceduresODS Graphs from Statistical ProceduresControlling ODS GraphicsControlling Labelling in GraphsODS Graphics EditorGraphs for Displaying the Characteristics of Univariate Data: Horse Racing, Mortality Rates, Forearm Lengths, Survival Times and Geyser EruptionsIntroductionPie Chart, Bar Cha

  17. Metallurgical comparison between the experimental ED-ODS and commercial ODS steels

    International Nuclear Information System (INIS)

    Fernandez, P.; Serrano, M.; Lapena, J.

    2007-01-01

    Full text of publication follows: Recently, reduced activation oxide dispersion strengthened ferritic/martensitic steels have been identified as potential structural material candidates for first wall and blanket structures of fusion devices. These steels allow to increase the operation temperature of the fusion reactor, around of 100 deg. C or even more, because of their excellent thermal creep resistance. ODS steels are being developed and investigated for nuclear fission and fusion applications in Japan, Europe and the United States. Commercial ODS products, such as MA956 and PM2000 are available and are being used for high temperature applications. Since no reduced activation ferritic/martensitic steels are commercially available at present, the European Materials Fusion Programme has considered in the last years initiate adequate research activities to produce and characterize these materials to evaluate the feasibility of their use in the different blanket designs. Nowadays, the ODS steel that are being extensively investigated in Europe is the denominated EU-ODS. This alloy has the basic composition of the Eurofer'97 with 0.3% of Y 2 O 3 particles. In this paper, the metallurgical properties (microstructural, Charpy, etc) of the newly developed EU-ODS steel are presented and discussed together with the properties of the commercial MA956 and PM2000 ODS steels, also studied in this work, in order to show the differences and similarities between these ODS alloys. (authors)

  18. Thermomechanical fatigue in single crystal superalloys

    Directory of Open Access Journals (Sweden)

    Moverare Johan J.

    2014-01-01

    Full Text Available Thermomechanical fatigue (TMF is a mechanism of deformation which is growing in importance due to the efficiency of modern cooling systems and the manner in which turbines and associated turbomachinery are now being operated. Unfortunately, at the present time, relatively little research has been carried out particularly on TMF of single crystal (SX superalloys, probably because the testing is significantly more challenging than the more standard creep and low cycle fatigue (LCF cases; the scarcity and relative expense of the material are additional factors. In this paper, the authors summarise their experiences on the TMF testing of SX superalloys, built up over several years. Emphasis is placed upon describing: (i the nature of the testing method, the challenges involved in ensuring that an given testing methodology is representative of engine conditions (ii the behaviour of a typical Re-containing second generation alloy such as CMSX-4, and its differing performance in out-of-phase/in-phase loading and crystallographic orientation and (iii the differences in behaviour displayed by the Re-containing alloys and new Re-free variants such as STAL15. It is demonstrated that the Re-containing superalloys are prone to different degradation mechanisms involving for example microtwinning, TCP precipitation and recrystallisation. The performance of STAL15 is not too inferior to alloys such as CMSX-4, suggesting that creep resistance itself does not correlate strongly with resistance to TMF. The implications for alloy design efforts are discussed.

  19. Barrier Coatings for Refractory Metals and Superalloys

    International Nuclear Information System (INIS)

    SM Sabol; BT Randall; JD Edington; CJ Larkin; BJ Close

    2006-01-01

    In the closed working fluid loop of the proposed Prometheus space nuclear power plant (SNPP), there is the potential for reaction of core and plant structural materials with gas phase impurities and gas phase transport of interstitial elements between superalloy and refractory metal alloy components during service. Primary concerns are surface oxidation, interstitial embrittlement of refractory metals and decarburization of superalloys. In parallel with kinetic investigations, this letter evaluates the ability of potential coatings to prevent or impede communication between reactor and plant components. Key coating requirements are identified and current technology coating materials are reviewed relative to these requirements. Candidate coatings are identified for future evaluation based on current knowledge of design parameters and anticipated environment. Coatings were identified for superalloys and refractory metals to provide diffusion barriers to interstitial transport and act as reactive barriers to potential oxidation. Due to their high stability at low oxygen potential, alumina formers are most promising for oxidation protection given the anticipated coolant gas chemistry. A sublayer of iridium is recommended to provide inherent diffusion resistance to interstitials. Based on specific base metal selection, a thin film substrate--coating interdiffusion barrier layer may be necessary to meet mission life

  20. Barrier Coatings for Refractory Metals and Superalloys

    Energy Technology Data Exchange (ETDEWEB)

    SM Sabol; BT Randall; JD Edington; CJ Larkin; BJ Close

    2006-02-23

    In the closed working fluid loop of the proposed Prometheus space nuclear power plant (SNPP), there is the potential for reaction of core and plant structural materials with gas phase impurities and gas phase transport of interstitial elements between superalloy and refractory metal alloy components during service. Primary concerns are surface oxidation, interstitial embrittlement of refractory metals and decarburization of superalloys. In parallel with kinetic investigations, this letter evaluates the ability of potential coatings to prevent or impede communication between reactor and plant components. Key coating requirements are identified and current technology coating materials are reviewed relative to these requirements. Candidate coatings are identified for future evaluation based on current knowledge of design parameters and anticipated environment. Coatings were identified for superalloys and refractory metals to provide diffusion barriers to interstitial transport and act as reactive barriers to potential oxidation. Due to their high stability at low oxygen potential, alumina formers are most promising for oxidation protection given the anticipated coolant gas chemistry. A sublayer of iridium is recommended to provide inherent diffusion resistance to interstitials. Based on specific base metal selection, a thin film substrate--coating interdiffusion barrier layer may be necessary to meet mission life.

  1. 75 FR 67100 - Superalloy Degassed Chromium From Japan

    Science.gov (United States)

    2010-11-01

    ... Chromium From Japan AGENCY: United States International Trade Commission. ACTION: Institution of a five-year review concerning the antidumping duty order on superalloy degassed chromium from Japan. SUMMARY... order on superalloy degassed chromium from Japan would be likely to lead to continuation or recurrence...

  2. 76 FR 8773 - Superalloy Degassed Chromium From Japan

    Science.gov (United States)

    2011-02-15

    ... INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-1090 (Review)] Superalloy Degassed Chromium From Japan AGENCY: United States International Trade Commission. ACTION: Termination of five-year... revocation of the antidumping duty order on superalloy degassed chromium from Japan would be likely to lead...

  3. Reduction in Defect Content of ODS Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ritherdon, J

    2001-05-15

    The work detailed within this report is a continuation of earlier work carried out under contract number 1DX-SY382V. The earlier work comprises a literature review of the sources and types of defects found principally in Fe-based ODS alloys as well as experimental work designed to identify defects in the prototype ODS-Fe{sub 3}Al alloy, deduce their origins and to recommend methods of defect reduction. The present work is an extension of the experimental work already reported and concentrates on means of reduction of defects already identified rather than the search for new defect types. This report also includes results gathered during powder separation trials, conducted by the University of Groningen, Netherlands and coordinated by the University of Liverpool, involving the separation of different metallic powders in terms of their differing densities. The scope and objectives of the present work were laid out in the technical proposal ''Reduction in Defect Content in ODS Alloys-III''. All the work proposed in the ''Statement of Work'' section of the technical proposal has been carried out and all work extra to the ''Statement of Work'' falls within the context of an ODS-Fe{sub 3}Al alloy of improved overall quality and potential creep performance in the consolidated form. The outturn of the experimental work performed is reported in the following sections.

  4. Development of high performance ODS alloys

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Lin [Texas A & M Univ., College Station, TX (United States); Gao, Fei [Univ. of Michigan, Ann Arbor, MI (United States); Garner, Frank [Texas A & M Univ., College Station, TX (United States)

    2018-01-29

    This project aims to capitalize on insights developed from recent high-dose self-ion irradiation experiments in order to develop and test the next generation of optimized ODS alloys needed to meet the nuclear community's need for high strength, radiation-tolerant cladding and core components, especially with enhanced resistance to void swelling. Two of these insights are that ferrite grains swell earlier than tempered martensite grains, and oxide dispersions currently produced only in ferrite grains require a high level of uniformity and stability to be successful. An additional insight is that ODS particle stability is dependent on as-yet unidentified compositional combinations of dispersoid and alloy matrix, such as dispersoids are stable in MA957 to doses greater than 200 dpa but dissolve in MA956 at doses less than 200 dpa. These findings focus attention on candidate next-generation alloys which address these concerns. Collaboration with two Japanese groups provides this project with two sets of first-round candidate alloys that have already undergone extensive development and testing for unirradiated properties, but have not yet been evaluated for their irradiation performance. The first set of candidate alloys are dual phase (ferrite + martensite) ODS alloys with oxide particles uniformly distributed in both ferrite and martensite phases. The second set of candidate alloys are ODS alloys containing non-standard dispersoid compositions with controllable oxide particle sizes, phases and interfaces.

  5. Irradiation response of ODS Eurofer97 steel

    Energy Technology Data Exchange (ETDEWEB)

    Luzginova, N.V., E-mail: luzginova@nrg.eu [Nuclear Research and Consultancy Group, Petten (Netherlands); Nolles, H.S.; Pierick, P. ten; Bakker, T.; Mutnuru, R.K.; Jong, M.; Blagoeva, D.T. [Nuclear Research and Consultancy Group, Petten (Netherlands)

    2012-09-15

    Oxide dispersion strengthened (ODS) Eurofer97 steel (EU batch, 0.3 wt.% of Y{sub 2}O{sub 3} particles), produced by mechanical alloying followed by hot rolling, is irradiated in the High Flux Reactor in Petten, The Netherlands at three different irradiation temperatures (300, 450 and 550 Degree-Sign C) up to nominal doses of 1 dpa and 3 dpa. The effect of neutron irradiation on the mechanical properties of ODS Eurofer97 material is investigated. It is shown that the irradiation hardening of ODS Eurofer97 steel occurs at 300 Degree-Sign C, whereas during irradiation at 450 and 550 Degree-Sign C no changes in mechanical properties are observed compared to the unirradiated material. This effect is possibly a result of the annealing of the irradiation damage at temperatures higher than 300 Degree-Sign C. The observed shifts in the Ductile to Brittle Transition Temperatures due to irradiation at different temperatures are discussed and compared with non-ODS Eurofer97 steel.

  6. OD structures in crystallography - basic concepts

    Czech Academy of Sciences Publication Activity Database

    Ďurovič, S.; Hybler, Jiří

    2006-01-01

    Roč. 221, - (2006), s. 63-76 ISSN 0044-2968 R&D Projects: GA ČR GA205/03/0439 Institutional research plan: CEZ:AV0Z10100521 Keywords : OD structures * polytypism * cronstedtite * kermesite * Fourier synthesis Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.897, year: 2006

  7. The effect of organisational context on organisational development (OD) interventions

    OpenAIRE

    Sanjana Brijball Parumasur

    2012-01-01

    Orientation: Systematic and congruent organisational structures, systems, strategies and designs are necessary for the successful implementation of organisational development (OD) interventions. Research purpose: This article examines national and international OD practices. It assesses the effect of diverse cultures and cultural values for determining the effectiveness of OD interventions. Motivation for the study: Most organisational change and development programmes fail and only a ...

  8. 46 CFR 280.4 - Standards governing payment of ODS.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Standards governing payment of ODS. 280.4 Section 280.4... Standards governing payment of ODS. (a) Full payment. Except to the extent otherwise provided in § 280.8, ODS shall be paid in full to the operator for vessel operations on the inbound and outbound legs of...

  9. Low-Cobalt Powder-Metallurgy Superalloy

    Science.gov (United States)

    Harf, F. H.

    1986-01-01

    Highly-stressed jet-engine parts made with less cobalt. Udimet 700* (or equivalent) is common nickel-based superalloy used in hot sections of jet engines for many years. This alloy, while normally used in wrought condition, also gas-atomized into prealloyed powder-metallurgy (PM) product. Product can be consolidated by hot isostatically pressing (HIPPM condition) and formed into parts such as turbine disk. Such jet-engine disks "see" both high stresses and temperatures to 1,400 degrees F (760 degrees C).

  10. Mechanical characterization of superalloys for space reactors

    International Nuclear Information System (INIS)

    Duchesne, J.

    1989-01-01

    The aim of this work is the selection of structural materials that can be used in the temperature range 600-900 0 C for a gas cooled space reactor producing electricity. Superalloys fit best the temperature range required. Five nickel base alloys are chosen for their good mechanical behaviour: HAYNES 230, HASTELLOY S, HASTELLOY X, HASTELLOY XR and PYRAD 38D. Metallography, tensile and hardness tests are realized. Sample contraction is evidenced for some creep tests, under low stress: 20MPa at 800 0 C, on HAYNES 230 and HASTELLOY X, probably related to the structural evolution of these materials corresponding to a decrease of the crystal parameter [fr

  11. Microstructural stability of 11Cr ODS steel

    Energy Technology Data Exchange (ETDEWEB)

    Yamashiro, Tetsuya, E-mail: fgsjkr@eng.hokudai.ac.jp [Materials Science and Engineering, Graduate School of Engineering, Hokkaido University, N13, W-8, Kita-ku, Sapporo 060-8628 (Japan); Ukai, Shigeharu; Oono, Naoko [Materials Science and Engineering, Faculty of Engineering, Hokkaido University, N13, W-8, Kita-ku, Sapporo 060-8628 (Japan); Ohtsuka, Satoshi; Kaito, Takeji [Advanced Nuclear System R& D Directorate, Japan Atomic Energy Agency (JAEA), 4002, Narita, Oarai, Ibaraki-pref. 311-1393 (Japan)

    2016-04-15

    Aiming at further improvement of high-temperature oxidation and corrosion resistance, 11CrODS steel with martensitic base structure has been previously developed, as a candidate fuel cladding material for 4th generation advanced nuclear reactors. In this study, the microstructure of 11CrODS steel was characterized by means of EBSD and nanoindentation hardness measurement. The continuous cooling transformation (CCT) diagram was constructed. Upper critical cooling rate, which is minimum cooling rate necessary to form martensitic structure, was derived to be 60 °C/min (3600 °C/h). In contrast, lower critical cooling rate preventing from martensite formation, was derived to be 10 °C/min (600 °C/h). An area fraction of so called residual ferrite was estimated by image processing of EBSD-IQ map to be 21% of the total area. This fraction of the residual ferrite in 11CrODS steel was evaluated by considering the driving force for α to γ reverse transformation.

  12. Proceedings of the Conference on Refractory Alloying Elements in Superalloys

    International Nuclear Information System (INIS)

    1984-01-01

    Some papers about the use of refractory metals in superalloys are presented. Mechanical properties, thermodynamics properties, use for nuclear fuels and corrosion resistance of those alloys are studied. (E.G.) [pt

  13. Grinding of Inconel 713 superalloy for gas turbines

    Czech Academy of Sciences Publication Activity Database

    Čapek, J.; Kyncl, J.; Kolařík, K.; Beránek, L.; Pitrmuc, Z.; Medřický, Jan; Pala, Z.

    2016-01-01

    Roč. 16, č. 1 (2016), s. 14-15 ISSN 1213-2489 Institutional support: RVO:61389021 Keywords : Casting defects * Gas turbine * Grinding * Nickel superalloy * Residual stresses Subject RIV: JJ - Other Materials

  14. Modelling and simulation of superalloys. Book of abstracts

    Energy Technology Data Exchange (ETDEWEB)

    Rogal, Jutta; Hammerschmidt, Thomas; Drautz, Ralf (eds.)

    2014-07-01

    Superalloys are multi-component materials with complex microstructures that offer unique properties for high-temperature applications. The complexity of the superalloy materials makes it particularly challenging to obtain fundamental insight into their behaviour from the atomic structure to turbine blades. Recent advances in modelling and simulation of superalloys contribute to a better understanding and prediction of materials properties and therefore offer guidance for the development of new alloys. This workshop will give an overview of recent progress in modelling and simulation of materials for superalloys, with a focus on single crystal Ni-base and Co-base alloys. Topics will include electronic structure methods, atomistic simulations, microstructure modelling and modelling of microstructural evolution, solidification and process simulation as well as the modelling of phase stability and thermodynamics.

  15. A high-throughput search for new ternary superalloys

    Science.gov (United States)

    Nyshadham, Chandramouli; Hansen, Jacob; Oses, Corey; Curtarolo, Stefano; Hart, Gus

    In 2006 an unexpected new superalloy, Co3[Al,W], was discovered. This new alloy is cobalt-based, in contrast to conventional superalloys, which are nickel-based. Inspired by this new discovery, we performed first-principles calculations, searching through 2224 ternary metallic systems of the form A3[B0.5C0.5], where A = Ni/Co/Fe and [B, C] = all binary combinations of 40 different elements chosen from the periodic table. We found 175 new systems that are better than the Co3[Al, W] superalloy. 75 of these systems are brand new--they have never been reported in experimental literature. These 75 new potential superalloys are good candidates for further experiments. Our calculations are consistent with current experimental literature where data exists. Work supported under: ONR (MURI N00014-13-1-0635).

  16. Water corrosion test of oxide dispersion strengthened (ODS) steel claddings

    International Nuclear Information System (INIS)

    Narita, Takeshi; Ukai, Shigeharu; Kaito, Takeji; Ohtsuka, Satoshi; Matsuda, Yasushi

    2006-07-01

    As a part of feasibility study of ODS steel cladding, its water corrosion resistance was examined under water pool condition. Although addition of Cr is effective for preventing water corrosion, excessive Cr addition leads to embrittlement due to the Cr-rich α' precipitate formation. In the ODS steel developed by the Japan Atomic Energy Agency (JAEA), the Cr content is controlled in 9Cr-ODS martensite and 12Cr-ODS ferrite. In this study, water corrosion test was conducted for these ODS steels, and their results were compared with that of conventional austenitic stainless steel and ferritic-martensitic stainless steel. Following results were obtained in this study. (1) Corrosion rate of 9Cr-ODS martensitic and 12Cr-ODS ferritic steel are significantly small and no pitting was observed. Thus, these ODS steels have superior resistance for water corrosion under the condition of 60degC and pH8-12. (2) It was showed that 9Cr-ODS martensitic steel and 12Cr-ODS ferritic steel have comparable water corrosion resistance to that of PNC316 and PNC-FMS at 60degC for 1,000h under varying pH of 8, 10. Water corrosion resistance of these alloys is slightly larger than that of PNC316 and PNC-FMS at pH12 without significant difference of appearance and uneven condition. (author)

  17. Low temperature gaseous nitriding of Ni based superalloys

    DEFF Research Database (Denmark)

    Eliasen, K. M.; Christiansen, Thomas Lundin; Somers, Marcel A. J.

    2010-01-01

    In the present work the nitriding response of selected Ni based superalloys at low temperatures is addressed. The alloys investigated are nimonic series nos. 80, 90, 95 and 100 and nichrome (Ni/Cr......In the present work the nitriding response of selected Ni based superalloys at low temperatures is addressed. The alloys investigated are nimonic series nos. 80, 90, 95 and 100 and nichrome (Ni/Cr...

  18. Development of a Refractory High Entropy Superalloy (Postprint)

    Science.gov (United States)

    2016-03-17

    hardened with HfC precipitates [2], Co-Re- or Co-Al-W-based alloys [3] or two-phase ( FCC + L12) refractory superalloys based on platinum group metals...Ni-based superalloys consisting of cuboids with the ordered L12 structure embedded in an FCC solid-solution matrix. Based on this microstructural...and 5). A comparison of the average atomic radii with the measured lattice parameters allows us to conclude that the disordered BCC phase forming

  19. Effect of interlayer composition diffusion bonding behavior of an ods nickel alloy

    International Nuclear Information System (INIS)

    Saha, R.K.; Khan, T.I.

    2005-01-01

    Oxide dispersion strengthened superalloys have been developed with excellent mechanical properties for use at elevated temperatures. However, in order to achieve commercial application an appropriate joining process is necessary which minimizes the disruption to the alloy microstructure. In transient liquid phase (TLP) diffusion Hardness, and bonding technique an interlayer containing melting point depressants is placed between the bonding surfaces and at the bonding temperature this interlayer melts and solidifies isothermally. In this study, TLP bonding technique , was used to join a Ni-based ODS alloy, MA 758, using a number of different nickel based interlayer compositions, namely, Ni-Cr-Fe-Si-B-Co, Ni-Cr-B, Ni-P and Ni-Cr-Si-B. These foils are ductile and melt quickly within a narrow temperature range producing strong, non-porous joints. The results showed that the hold time at the bonding temperature affected the rate of isothermal solidification during the TLP bonding process. Furthermore, the use of a post-bond heat treatment helped to homogenize the joint region. (author)

  20. Creep and rupture of an ODS alloy with high stress rupture ductility. [Oxide Dispersion Strengthened

    Science.gov (United States)

    Mcalarney, M. E.; Arsons, R. M.; Howson, T. E.; Tien, J. K.; Baranow, S.

    1982-01-01

    The creep and stress rupture properties of an oxide (Y2O3) dispersion strengthened nickel-base alloy, which also is strengthened by gamma-prime precipitates, was studied at 760 and 1093 C. At both temperatures, the alloy YDNiCrAl exhibits unusually high stress rupture ductility as measured by both elongation and reduction in area. Failure was transgranular, and different modes of failure were observed including crystallographic fracture at intermediate temperatures and tearing or necking almost to a chisel point at higher temperatures. While the rupture ductility was high, the creep strength of the alloy was low relative to conventional gamma prime strengthened superalloys in the intermediate temperature range and to ODS alloys in the higher temperature range. These findings are discussed with respect to the alloy composition; the strengthening oxide phases, which are inhomogeneously dispersed; the grain morphology, which is coarse and elongated and exhibits many included grains; and the second phase inclusion particles occurring at grain boundaries and in the matrix. The creep properties, in particular the high stress dependencies and high creep activation energies measured, are discussed with respect to the resisting stress model of creep in particle strengthened alloys.

  1. Changes in the properties of superalloys by long term heating

    International Nuclear Information System (INIS)

    Susukida, H.; Tsuji, I.; Kawai, H.

    1976-01-01

    A laboratory study was conducted in order to determine the effect of long term heating (max. 10000h at 850 0 and 950 0 C) on the microstructure, tensile properties, hardness and stress rupture properties of four kinds of superalloys. These superalloys are two kinds of solid solution hardened Ni-base superalloys Hastelloy X and Inconel 617 and two kinds of dispersion strengthened Ni-base superalloys TD-Ni and TD-NiCr. The result of the study can be summarized as follows: (1) Solid solution hardened superalloys: Many precipitates were observed in the grains and on the grain boundaries after 100 hours of heating, and the precipitates became coarse-grained by over 1000 hours of heating. This tendency was remarkable when they were heated at 950 0 C. With the change of their microstructure, their mechanical properties also changed, particularly their tensile ductility decreased remarkably. (2) Dispersion strengthened superalloys: Their microstructure and mechanical properties were almost unchanged by long term heating. (3) The authors proposed ''solid solution hardening value'' in order to grasp quantitatively the solid solution hardening which has been discussed by the content of each element hitherto. (auth.)

  2. Studies on phase kinetics of new superalloys

    International Nuclear Information System (INIS)

    Weisbrodt, A.; Penkalla, H.J.; Schubert, F.; Nickel, H.

    1990-08-01

    At the development of new ODS (Oxide-Dispersion-Strengthened) alloys for components being exposed to hot-gas temperatures nickel-base alloys and ODS alloys have been investigated. The experimental work mainly referred to phase investigations of thermally loaded samples. The addition of alloying elements will have a decisive influence on the γ'-phase fraction, γ'-lattice parameter, the morphology as well as the coarsening behaviour of the γ'-phase under temperature load. The main characteristics of ODS alloys are Y,Al-mixed oxides and microstructural inhomogenities. As for MA6000 a Time-Temperature-Precipitation diagram has been elaborated. By means of the improved computer programme PHASCALC for phase and N v (= average electron vacancy concentration) - value calculation many microstructural parameters such as the γ/γ'-misfit, the solution of the γ'-phase and melting temperatures can be determined. Tensile tests made at temperatures above 900deg C have shown that the strengthening parameters are dependent on alloy composition, temperature conditions, γ'-phase fraction and oxide dispersion content. (orig.) [de

  3. The Bgo-Od Experiment at Elsa

    Science.gov (United States)

    Bantes, B.; Bayadilov, D.; Beck, R.; Becker, M.; Bella, A.; Bieling, J.; Böse, S.; Braglieri, A.; Brinkmann, K.; Burdeynyi, D.; Curciarello, F.; de Leo, V.; di Salvo, R.; Dutz, H.; Elsner, D.; Fantini, A.; Frese, T.; Friedrick, S.; Frommberger, F.; Ganenko, V.; Gervino, G.; Ghio, F.; Giardina, G.; Girolami, B.; Glazier, D.; Goertz, S.; Gridnev, A.; Gutz, E.; Hammann, D.; Hannappel, J.; Hillert, W.; Ignatov, A.; Jahn, O.; Jahn, R.; Joosten, R.; Jude, T. C.; Klein, F.; Koop, K.; Krusche, B.; Lapik, A.; Levi Sandri, P.; Lopatin, I.; Mandaglio, G.; Messi, F.; Messi, R.; Metag, V.; Moricciani, D.; Nanova, M.; Nedorezov, V.; Noviskiy, D.; Pedroni, P.; Romaniuk, M.; Rostomyan, T.; Schaerf, C.; Schmieden, H.; Sumachev, V.; Tarakonov, V.; Vegna, V.; Vlasov, P.; Walther, D.; Watts, D.; Zaunick, H.-G.; Zimmermann, T.

    2014-01-01

    Meson photoproduction is a key tool for the experimental investigation of the nucleon excitation spectrum. To disentangle the specific couplings of resonances, in addition to the rather well measured pion and eta photoproduction channels it is mandatory to obtain information on channels involving strange and vector mesons and higher mass pseudoscalar mesons, and the associated multi-particle final states with both charged and neutral particles. In this respect, the new BGO-OD experiment at the ELSA accelerator of the University of Bonn's Physikalisches Institut provides unique instrumentation. We describe the experiment, present its status and the initial program of measurements.

  4. Behaviour of ODS Steels in Cyclic Loading

    Czech Academy of Sciences Publication Activity Database

    Kuběna, Ivo; Kruml, Tomáš; Polák, Jaroslav

    2016-01-01

    Roč. 69, č. 2 (2016), s. 309-313 ISSN 0972-2815. [International Conference on CREEP , FATIGUE and CREEP -FATIGUE INTERACTION /7./. Kalpakkam, 19.01.2016-22.01.2016] R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068; GA ČR GA15-08826S Institutional support: RVO:68081723 Keywords : ODS steels * low cycle fatigue * small fatigue crack * microstructure Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 0.533, year: 2016 http://link.springer.com/article/10.1007/s12666-015-0814-3

  5. Creep Behaviour of Modified Mar-247 Superalloy

    Directory of Open Access Journals (Sweden)

    Cieśla M.

    2016-06-01

    Full Text Available The paper presents the results of analysis of creep behaviour in short term creep tests of cast MAR-247 nickel-based superalloy samples made using various modification techniques and heat treatment. The accelerated creep tests were performed under temperature of 982 °C and the axial stresses of σ = 150 MPa (variant I and 200 MPa (variant II. The creep behaviour was analysed based on: creep durability (creep rupture life, steady-state creep rate and morphological parameters of macro- and microstructure. It was observed that the grain size determines the creep durability in case of test conditions used in variant I, durability of coarse-grained samples was significantly higher.

  6. Creep-fatigue of low cobalt superalloys

    Science.gov (United States)

    Halford, G. R.

    1982-01-01

    Testing for the low cycle fatigue and creep fatigue resistance of superalloys containing reduced amounts of cobalt is described. The test matrix employed involves a single high temperature appropriate for each alloy. A single total strain range, again appropriate to each alloy, is used in conducting strain controlled, low cycle, creep fatigue tests. The total strain range is based upon the level of straining that results in about 10,000 cycles to failure in a high frequency (0.5 Hz) continuous strain-cycling fatigue test. No creep is expected to occur in such a test. To bracket the influence of creep on the cyclic strain resistance, strain hold time tests with ore minute hold periods are introduced. One test per composition is conducted with the hold period in tension only, one in compression only, and one in both tension and compression. The test temperatures, alloys, and their cobalt compositions that are under study are given.

  7. Hydrogen Annealing Of Single-Crystal Superalloys

    Science.gov (United States)

    Smialek, James L.; Schaeffer, John C.; Murphy, Wendy

    1995-01-01

    Annealing at temperature equal to or greater than 2,200 degrees F in atmosphere of hydrogen found to increase ability of single-crystal superalloys to resist oxidation when subsequently exposed to oxidizing atmospheres at temperatures almost as high. Supperalloys in question are principal constituents of hot-stage airfoils (blades) in aircraft and ground-based turbine engines; also used in other high-temperature applications like chemical-processing plants, coal-gasification plants, petrochemical refineries, and boilers. Hydrogen anneal provides resistance to oxidation without decreasing fatigue strength and without need for coating or reactive sulfur-gettering constituents. In comparison with coating, hydrogen annealing costs less. Benefits extend to stainless steels, nickel/chromium, and nickel-base alloys, subject to same scale-adhesion and oxidation-resistance considerations, except that scale is chromia instead of alumina.

  8. Dissimilar Joining of ODS and F/M Steel Tube by Friction Stir Welding

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Suk Hoon; Noh, Sanghoon; Kim, Jun Hwan; Kim, Tae Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Oxide Dispersion strengthened (ODS) steels, it is well known that uniform nano-oxide dispersoids act as pinning points to obstruct dislocation and grain boundary motion, however, those advantages will be disappeared while the material is subjected to the high temperature of conventional fusion welding. Rotary friction welding, also referred to as friction stir welding (FSW), has shown great promise as a method for welding traditionally difficult to weld materials such as aluminum alloys. This relatively new technology has more recently been applied to higher melting temperature alloys such as steels, nickel-based and titanium alloys. Friction stir processing (FSP) is a method of changing the properties of a metal through intense, localized plastic deformation. FSW is the precursor of the FSP technique. When ideally implemented, this process mixes the material without changing the phase and creates a microstructure with fine, equiaxed grains. This homogeneous grain structure, separated by high-angle boundaries, allows some alloys to take on superplastic properties. In this study, FSW is used as a substitutive welding process between FMS tube and ODS parts. The dimension of tube is 7.0 OD, 0.5 T. During the FSW, dynamic-recrystallized grains are developed; the uniform oxides Dispersion is preserved in the metal matrix. The microstructure and microtexture of the material near the stir zone is found to be influenced by the rotational behavior of the tool. The additive effect from FSP on sample surface is considered. Since the mechanical alloying (MA) and FSP commonly apply extreme shear deformation on materials, the Dispersion of oxide particle in ODS steels is very active during both processes. Friction stir welding appears to be a very promising technique for the welding of FMS and ODS steels in the form of sheet and tube. FSW could successfully produce defect-free welds on FMS tubes and ODS ring assembly. FSW produces a fine grain structure consisting of ferrite and

  9. Dissimilar Joining of ODS and F/M Steel Tube by Friction Stir Welding

    International Nuclear Information System (INIS)

    Kang, Suk Hoon; Noh, Sanghoon; Kim, Jun Hwan; Kim, Tae Kyu

    2014-01-01

    Oxide Dispersion strengthened (ODS) steels, it is well known that uniform nano-oxide dispersoids act as pinning points to obstruct dislocation and grain boundary motion, however, those advantages will be disappeared while the material is subjected to the high temperature of conventional fusion welding. Rotary friction welding, also referred to as friction stir welding (FSW), has shown great promise as a method for welding traditionally difficult to weld materials such as aluminum alloys. This relatively new technology has more recently been applied to higher melting temperature alloys such as steels, nickel-based and titanium alloys. Friction stir processing (FSP) is a method of changing the properties of a metal through intense, localized plastic deformation. FSW is the precursor of the FSP technique. When ideally implemented, this process mixes the material without changing the phase and creates a microstructure with fine, equiaxed grains. This homogeneous grain structure, separated by high-angle boundaries, allows some alloys to take on superplastic properties. In this study, FSW is used as a substitutive welding process between FMS tube and ODS parts. The dimension of tube is 7.0 OD, 0.5 T. During the FSW, dynamic-recrystallized grains are developed; the uniform oxides Dispersion is preserved in the metal matrix. The microstructure and microtexture of the material near the stir zone is found to be influenced by the rotational behavior of the tool. The additive effect from FSP on sample surface is considered. Since the mechanical alloying (MA) and FSP commonly apply extreme shear deformation on materials, the Dispersion of oxide particle in ODS steels is very active during both processes. Friction stir welding appears to be a very promising technique for the welding of FMS and ODS steels in the form of sheet and tube. FSW could successfully produce defect-free welds on FMS tubes and ODS ring assembly. FSW produces a fine grain structure consisting of ferrite and

  10. The effect of organisational context on organisational development (OD interventions

    Directory of Open Access Journals (Sweden)

    Sanjana Brijball Parumasur

    2012-05-01

    Research purpose: This article examines national and international OD practices. It assesses the effect of diverse cultures and cultural values for determining the effectiveness of OD interventions. Motivation for the study: Most organisational change and development programmes fail and only a few result in increased competitiveness, improvements and profitability. This emphasises the need for change interventions to give sufficient attention to leadership, cultures, managing change and adopting context-based OD interventions. Research design, approach and method: This article is a literature review of the current trends and research in the area of OD interventions. It synthesises the influence that cultures and cultural orientations have on determining which OD intervention strategies organisations should adopt in different cultures. Main findings: The analysis emphasises how important it is to achieve congruence between the OD interventions organisations select and their local cultures. Practical/managerial implications: It is important to note the evolving nature of the political and economic climates that influence national cultures and that they emphasise that interventions that reflect OD values, which are tailor-made and shaped to the needs of local cultures, are necessary. Contribution/value-add: This study links various OD interventions to Hofstede’s dimensions for differentiating national cultures. It provides guidelines for aligning the practices and techniques of OD to the values and cultures of the organisations and societies in which they are to be implemented.

  11. Microstructure properties relationship in transient liquid phase diffusion bonds made in MA 758 superalloy

    International Nuclear Information System (INIS)

    Ekrami, A.

    2003-01-01

    Transient liquid phase diffusion bonding procedure was used to join an ODS Ma 758 superalloy in two conditions, wrought fine grains, and recrystallised grains. An Ni-Cr-B-Si alloy was used as an interlayer. Bonding was carried out at 1100 d ig C for bonding hold times of 15,30, and 60 minutes under vacuum of 6x10 -4 torr. Bonded samples were homogenized at 1360 d ig C for one hour and then cooled with a rate of 15 d ig C /min. Shear and fatigue strengths of bonds were determined. The results showed that there is no effect of bonding hold times on shear strength after bonding hold time of 30 minutes. At a given bonding hold time, the shear strength of bonds made in the recrystallized condition was greater than the shear strength of bonds made in the fine grain condition. The same was true for fatigue strength at a given cycle to fracture. Transient liquid phase bonding was also carried out under pressure of 0.1 Mpa under the same temperature and bonding hold time for fine grain material. Microstructure studies of bonds made under pressure showed no effects of pressure on bond region grain size. Shear tests results also demonstrate little effects of pressure on shear strength of bonds

  12. Activation volume of martensitic ODS steel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, D. W.; Noh, S.; Kim, T. K. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    Apparent activation volume as a function of temperature is 86b{sup 3}-42b{sup 3}. Activation volume decreases with increasing temperature. Activation volume changes scarcely with decreasing strain rate. Strain rate sensitivity increases with increasing temperature and decreasing strain rate. Nano-sized oxide dispersion strengthened (ODS) martensitic steel has a high strength, low thermal expansion coefficient, high thermal conductivity, and a good swelling resistance. Martensitic ODS steel is a candidate material for fuel cladding of sodium cooled fast breeder reactor (SFR). The plastic flow stress is determined through the interaction of dislocations with the obstacles encountered inside lattice. Dislocation movement through the lattice or past an obstacle requires surmounting of the energy barrier by a combination of applied stress and thermal activation. The plastic deformation of materials is a thermally activated process dependent upon time, temperature, and strain rate. Characterization of the rate controlling mechanism for plastic deformation due to dislocation motion in crystalline materials is done by the assessment of activation volume based on thermal activation analysis.

  13. 46 CFR 280.9 - Special rules for last year of ODS agreement.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Special rules for last year of ODS agreement. 280.9... LINER OPERATORS § 280.9 Special rules for last year of ODS agreement. (a) Reduction in payment of ODS. ODS payable during the last year of any ODS agreement shall be reduced, as provided in paragraph (b...

  14. Preparation of Inconel 740 superalloy by electron beam smelting

    Energy Technology Data Exchange (ETDEWEB)

    You, Xiaogang [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116023 (China); Laboratory for New Energy Material Energetic Beam Metallurgical Equipment Engineering of Liaoning Province, Dalian 116024 (China); Tan, Yi, E-mail: tanyi@dlut.edu.cn [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116023 (China); Laboratory for New Energy Material Energetic Beam Metallurgical Equipment Engineering of Liaoning Province, Dalian 116024 (China); You, Qifan; Shi, Shuang; Li, Jiayan [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116023 (China); Laboratory for New Energy Material Energetic Beam Metallurgical Equipment Engineering of Liaoning Province, Dalian 116024 (China); Ye, Fei [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116023 (China); Wei, Xin [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116023 (China); Laboratory for New Energy Material Energetic Beam Metallurgical Equipment Engineering of Liaoning Province, Dalian 116024 (China)

    2016-08-15

    A novel method, namely electron beam smelting (EBS) technology was used to prepare the Inconel 740 superalloy. The microstructures, hardness and oxidation behavior were characterized and compared with the traditionally prepared Inconel 740 superalloy. The results imply that the solution treatment gives rise to the coarsening of γ′ precipitates, with further aging treatment, the γ′ precipitates with size of less than 30 nm are distributed dispersively in the matrix, leading to a decreasing of the lattice parameters and an increasing of the misfit. The γ′ precipitates result in shearing mechanism of weakly pair coupling. The EBS 740 superalloy produces better properties than that prepared in the traditional method in both precipitation strengthening effect and oxidation resistance. - Highlights: • Electron beam smelting, a new method, was used to prepare the Inconel 740 superalloy. • The EBS 740 shows higher strengthening effect than 740 made in traditional method. • The EBS 740 shows better oxidation resistance than traditional 740. • It shows application prospect of EBS technology in preparing Ni-base superalloys.

  15. Water corrosion resistance of ODS ferritic-martensitic steel tubes

    International Nuclear Information System (INIS)

    Narita, Takeshi; Ukai, Shigeharu; Kaito, Takeji; Ohtsuka, Satoshi; Matsuda, Yasuji

    2008-01-01

    Oxide dispersion strengthened (ODS) ferritic-martensitic steels have superior radiation resistance; it is possible to achieve a service temperature of up to around 973 K because of their superior creep strength. These advantages of ODS steels facilities their application to long-life cladding tubes in advanced fast reactor fuel elements. In addition to neutron radiation resistance, sufficient general corrosion resistance to maintain the strength of the cladding, and the stress corrosion cracking (SCC) resistance for spent-fuel-pool cooling systems and high-temperature oxidation for the fuel-clad chemical interaction (FCCI) of ODS ferritic steel are required. Although the addition of Cr to ODS is effective in preventing water corrosion and high-temperature oxidation, an excessively high amount of Cr leads to embrittlement due to the formation of a Cr-rich α' precipitate. The Cr content in 9Cr-ODS martensite and 12Cr-ODS ferrite, the ODS steels developed by the Japan Atomic Energy Agency (JAEA), is controlled. In a previous paper, it has been demonstrated that the resistances of 9Cr- and 12Cr-ODS ferritic-martensitic steels for high-temperature oxidation are superior to those of conventional 12Cr ferritic steel. However, the water corrosion data of ODS ferritic-martensitic steels are very limited. In this study, a water corrosion test was conducted on ODS steels in consideration of the spent-fuel-pool cooling condition, and the results were compared with those of conventional austenitic stainless steel and ferritic-martensitic stainless steel. (author)

  16. Noburnium: Systems design of niobium superalloys

    Science.gov (United States)

    Misra, Abhijeet

    2005-11-01

    A systems-based approach, integrating quantum mechanical calculations with efficient experimentation, was employed to design niobium-based superalloys. The microstructural concept of gamma-gamma' nickel-based superalloys was adopted, where, the coherent gamma ' aluminides act both as the strengthening phase and a source of aluminum for Al2O3 passivation. Building on previous research, the selected bcc-type ordered aluminide was L2 1 structured Pd2HfAl phase. Comprehensive phase relations were measured on Nb-Pd-Hf-Al prototype alloys, and key tie-tetrahedra were identified. Aluminide precipitation in a bcc matrix was demonstrated in designed Nb+Pd2HfAl alloys. Thermodynamic databases were developed by integrating first-principles calculations with measured phase relations. Atomic volume models were developed for the bcc matrix and the Pd2HfAl phase and matrix elements which would reduce lattice misfit were identified. An experimental 2-phase alloy demonstrated a misfit of 3%. A modified Wagner's model was used to predict the required transient properties to form external Al2O3. The principal oxidation design goal was to decrease the oxygen permeability ( NSOx DO ) divided by the aluminum diffusivity (DAl) by 5 orders of magnitude. A multicomponent mobility database was developed to predict the diffusivities. Guided by first-principles calculations the effect of alloying elements on the oxygen diffusivity in Nb was measured, and the mobility database was experimentally validated. Based on the mobility database, it was found that increasing Al solubility in the bcc matrix greatly increased Al diffusivity. Alloying elements were identified that would increase Al solubility in the bcc matrix. Prototype alloys were prepared and the best oxidation performance was exhibited by a bcc+Nb2Al Nb-Hf-Al alloy, which exhibited parabolic oxidation behavior at 1300°C. The alloy was shown to have achieved the required 5 orders of magnitude reduction in the design parameter. The

  17. Positron annihilation characteristics of ODS and non-ODS EUROFER isochronally annealed

    International Nuclear Information System (INIS)

    Ortega, Y.; Castro, V. de; Monge, M.A.; Munoz, A.; Leguey, T.; Pareja, R.

    2008-01-01

    Yttrium oxide dispersion strengthened (ODS) and non-ODS EUROFER produced by mechanical alloying and hot isostatic pressing have been subjected to isochronal annealing up to 1523 K, and the evolution of the open-volume defects and their thermal stability have been investigated using positron lifetime and coincidence Doppler broadening (CDB) techniques. Transmission electron microscopy (TEM) observations have also been performed on the studied samples to verify the characteristics of the surviving defects after annealing at 1523 K. The CDB spectra of ODS EUROFER exhibit a characteristic signature that is attributed to positron annihilation in Ar-decorated cavities at the oxide particle/matrix interfaces. The variation of the positron annihilation parameters with the annealing temperature shows three stages: up to 623 K, between 823 and 1323 K, and above 1323 K. Three-dimensional vacancy clusters, or voids, are detected in either materials in as-HIPed condition and after annealing at T ≤ 623 K. In the temperature range 823-1323 K, these voids' growth and nucleation and the growth of other new species of voids take place. Above 1323 K, some unstable cavities start to anneal out, and cavities associated to oxide particles and other small precipitates survive to annealing at 1523 K. The TEM observations and the positron annihilation results indicate that these cavities should be decorated with Ar atoms absorbed during the mechanical alloying process

  18. Positron annihilation characteristics of ODS and non-ODS EUROFER isochronally annealed

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, Y. [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain)], E-mail: yanicet@fis.ucm.es; Castro, V. de; Monge, M.A.; Munoz, A.; Leguey, T.; Pareja, R. [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain)

    2008-05-31

    Yttrium oxide dispersion strengthened (ODS) and non-ODS EUROFER produced by mechanical alloying and hot isostatic pressing have been subjected to isochronal annealing up to 1523 K, and the evolution of the open-volume defects and their thermal stability have been investigated using positron lifetime and coincidence Doppler broadening (CDB) techniques. Transmission electron microscopy (TEM) observations have also been performed on the studied samples to verify the characteristics of the surviving defects after annealing at 1523 K. The CDB spectra of ODS EUROFER exhibit a characteristic signature that is attributed to positron annihilation in Ar-decorated cavities at the oxide particle/matrix interfaces. The variation of the positron annihilation parameters with the annealing temperature shows three stages: up to 623 K, between 823 and 1323 K, and above 1323 K. Three-dimensional vacancy clusters, or voids, are detected in either materials in as-HIPed condition and after annealing at T {<=} 623 K. In the temperature range 823-1323 K, these voids' growth and nucleation and the growth of other new species of voids take place. Above 1323 K, some unstable cavities start to anneal out, and cavities associated to oxide particles and other small precipitates survive to annealing at 1523 K. The TEM observations and the positron annihilation results indicate that these cavities should be decorated with Ar atoms absorbed during the mechanical alloying process.

  19. OD in Schools: The State of the Art. Vol. II: Review of Research on OD. Final Report.

    Science.gov (United States)

    Fullan, Michael; And Others

    The purpose of this document, the second of a five-volume series, was to analyze the various reviews of organizational development (OD) in general, and case studies of school districts in particular, in order to synthesize information about OD as it applies to schools. The review is organized into four main categories: (1) values, themes, and…

  20. Surface Modification Technology of ODS Alloying Treatment by using Laser Heat Source

    International Nuclear Information System (INIS)

    Kim, H. G.; Kim, I. H.; Choi, B. K.; Park, J. Y.; Koo, Y. H.

    2012-01-01

    The ODS (Oxide Dispersion Strengthed) alloys can be applied as structural materials for components in the core of a nuclear power plants since these components must have a high mechanical strength at high temperature up to 700 .deg. C. This type of alloy was generally manufactured by mechanical alloying from its source metal and Y 2 O 3 powders. The mechanical alloyed powder is subjected to the HIP (Hot Isotatic Pressing) or hot extrusion: and this product is heat treated at target temperature and time. Thus, the Y 2 O 3 particles are dispersed in the metal matrix. These manufacturing process of ODS alloy is very complex and expensive. Also, it is necessary the special techniques to obtain the uniform dispersion and volume control of Y 2 O 3 particles. Another problem is the final product forming such as tube and sheet because the intermediated-product has a high mechanical strength due to the dispersion of Y 2 O 3 particles. The laser cladding techniques was applied on the surface cladding of ceramics and inter-metallic compounds on metal base and ceramic base components to increase corrosion and wear resistance. The laser heat source can be used to the alloying the metal and ceramic materials, because thermally melting of metal and ceramic is possible. So, we are applied on ODS alloy manufacturing by using the laser heat source. The main advantages and disadvantage of this technology can be resumed as follows: · It is possible to apply to the sheet and tube shape component, directly. · Metallurgical damage such as HAZ and severe grain growth is considerably reduced. · Good control of the alloying element of the treated zone · Highly reproducible homogeneous zone · The pores and cracks are suppressed in the treated zone · Oxidation can be prevented during the process. · Good control is possible for the irregular shaped components. · The bulk material alloying is limited by the power of laser source. So, this work is studied on the ODS alloy manufacturing

  1. Mechanical and Microstructure Study of Nickel-Based ODS Alloys Processed by Mechano-Chemical Bonding and Ball Milling

    Science.gov (United States)

    Amare, Belachew N.

    Due to the need to increase the efficiency of modern power plants, land-based gas turbines are designed to operate at high temperature creating harsh environments for structural materials. The elevated turbine inlet temperature directly affects the materials at the hottest sections, which includes combustion chamber, blades, and vanes. Therefore, the hottest sections should satisfy a number of material requirements such as high creep strength, ductility at low temperature, high temperature oxidation and corrosion resistance. Such requirements are nowadays satisfied by implementing superalloys coated by high temperature thermal barrier coating (TBC) systems to protect from high operating temperature required to obtain an increased efficiency. Oxide dispersive strengthened (ODS) alloys are being considered due to their high temperature creep strength, good oxidation and corrosion resistance for high temperature applications in advanced power plants. These alloys operating at high temperature are subjected to different loading systems such as thermal, mechanical, and thermo-mechanical combined loads at operation. Thus, it is critical to study the high temperature mechanical and microstructure properties of such alloys for their structural integrity. The primary objective of this research work is to investigate the mechanical and microstructure properties of nickel-based ODS alloys produced by combined mechano-chemical bonding (MCB) and ball milling subjected to high temperature oxidation, which are expected to be applied for high temperature turbine coating with micro-channel cooling system. Stiffness response and microstructure evaluation of such alloy systems was studied along with their oxidation mechanism and structural integrity through thermal cyclic exposure. Another objective is to analyze the heat transfer of ODS alloy coatings with micro-channel cooling system using finite element analysis (FEA) to determine their feasibility as a stand-alone structural

  2. Metallurgical optimisation of PM superalloy N19

    Directory of Open Access Journals (Sweden)

    Locq Didier

    2014-01-01

    Full Text Available Microstructures of the new PM superalloy N19 have been investigated for various heat treatments in order to reach the best compromise between static strength and cyclic resistance. One subsolvus and several supersolvus heat treatments were applied to produce fine (7 μm and medium (25 μm grain sizes, respectively. The alloy is shown to be quite sensitive to the cooling conditions after solutioning as the γ′ hardening precipitates, both secondary and tertiary, have a direct influence on mechanical properties. Two cooling conditions after solutioning produce a high crack propagation resistance at 650 °C with dwell time cycles, which is one of the basic requirements. The low cycle fatigue behaviour appears to be correlated to the grain size, which determines the origin of crack initiation (from ceramic inclusions or not. The other mechanical properties (tensile, creep remain above target levels. Despite the medium size grain microstructure in the supersolvus condition, a high level of mechanical strength is observed in N19 at elevated temperature. It is understood that further improvement in properties can be achieved by developing coarse grain microstructures.

  3. Boride particles in a powder metallurgy superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Witt, M C; Charles, J A

    1985-12-01

    Using optical and electron metallography, the composition, morphology, and distribution of M/sub 3/B/sub 2/ borides in as-hipped (hot isostatically pressed) samples of the powder metallurgy superalloy Nimonic AP1 have been determined. Two types of boride are present depending on the HIP temperature. Hipping below the boride solvus results in low-aspect ratio particles, distributed both inter- and intragranularly. Hipping above the boride solvus produces high-aspect ratio particles which are exclusively intergranular. A small difference in both lattice parameter and composition has been measured. Electron energy loss spectroscopy of the particles has confirmed the presence of boron, and laser ion-induced mass analysis has indicated a low carbon level. The higher susceptibility to edge cracking during forging of material hipped above the boride solvus is related to the boride morphology. Studies of the subsequent recrystallization of the forged samples have indicated that necklace formation is neither inhibited nor accelerated by the presence of grain boundary borides. 18 references.

  4. Evaluation of powder metallurgy superalloy disk materials

    Science.gov (United States)

    Evans, D. J.

    1975-01-01

    A program was conducted to develop nickel-base superalloy disk material using prealloyed powder metallurgy techniques. The program included fabrication of test specimens and subscale turbine disks from four different prealloyed powders (NASA-TRW-VIA, AF2-1DA, Mar-M-432 and MERL 80). Based on evaluation of these specimens and disks, two alloys (AF2-1DA and Mar-M-432) were selected for scale-up evaluation. Using fabricating experience gained in the subscale turbine disk effort, test specimens and full scale turbine disks were formed from the selected alloys. These specimens and disks were then subjected to a rigorous test program to evaluate their physical properties and determine their suitability for use in advanced performance turbine engines. A major objective of the program was to develop processes which would yield alloy properties that would be repeatable in producing jet engine disks from the same powder metallurgy alloys. The feasibility of manufacturing full scale gas turbine engine disks by thermomechanical processing of pre-alloyed metal powders was demonstrated. AF2-1DA was shown to possess tensile and creep-rupture properties in excess of those of Astroloy, one of the highest temperature capability disk alloys now in production. It was determined that metallographic evaluation after post-HIP elevated temperature exposure should be used to verify the effectiveness of consolidation of hot isostatically pressed billets.

  5. Mechanical characterization of superalloys for space reactors

    International Nuclear Information System (INIS)

    Duchesne, J.

    1989-01-01

    The purpose of this work is the choice of materials usable between 600 and 900 0 C for nuclear space reactor structures. The main criterion of selection for these materials is their good creep behaviour. Consequently, macroscopic theories of creep and several extrapolation methods were described. Superalloys seem the best materials for the studied range of temperatures. Five of them, base nickel, ones unusual in nuclear industry were selected for their good mechanical properties. Three of them are industrial alloys: the first, HAYNES 230 is a recent one, HASTELLOY S and X are more standard materials. The last two, HASTELLOY XR and PYRAD 38 D are issued from special fabrications. Creep tests metallographic investigations, hardness and tensile tests were performed. A contraction of samples was observed during some creep tests under a low stress, 20MPa at 800 0 C, for HAYNES 230 and HASTELLOY X. This could be due to a structural evolution of these materials connected to a decrease of the cristalline parameter. In addition, correlations were observed between certain characteristics determined from slow tensile tests and short duration creep tests. These correlations present a large interest because, at the present time, creep tests cannot be executed on irradiated materials in our laboratories. Consequently creep behaviour of irradiated materials seem may be deduced. Further studies are needed to explain and confirm the behaviour of the most interesting materials under low stresses: HAYNES 230 and HASTELLOY XR to anticipate their behaviour in working conditions [fr

  6. Surface alloying of nickel based superalloys by laser

    International Nuclear Information System (INIS)

    Rodriguez, G.P.; Garcia, I.; Damborenea, J.J. de

    1998-01-01

    Ni based superalloys present a high oxidation resistance at high temperature as well as good mechanical properties. But new technology developments force to research in this materials to improve their properties at high temperature. In this work, two Ni based superalloys (Nimonic 80A and Inconel 600) were surface alloyed with aluminium using a high power laser. SEM and EDX were used to study the microstructure of the obtained coatings. Alloyed specimens were tested at 1.273 K between 24 and 250 h. Results showed the generation of a protective and continuous coating of alumina on the laser treated specimens surface that can improve oxidation resistance. (Author) 8 refs

  7. Chlamydia - CDC Fact Sheet

    Science.gov (United States)

    ... Archive STDs Home Page Bacterial Vaginosis (BV) Chlamydia Gonorrhea Genital Herpes Hepatitis HIV/AIDS & STDs Human Papillomavirus ( ... sheet Pelvic Inflammatory Disease (PID) – CDC fact sheet Gonorrhea – CDC fact sheet STDs Home Page Bacterial Vaginosis ( ...

  8. Crossed beam studies of O-+D2→OD-+D

    International Nuclear Information System (INIS)

    Johnson, S.G.; Kremer, L.N.; Metral, C.J.; Cross, R.J.

    1978-01-01

    Using the crossed-beam machine EVA we have measured the product angular and energy distributions of the reaction O - +D 2 →OD - +D in the relative energy range of 1.2-4.7 eV (5.7-23.1 eV LAB). Below 2.5 eV the product distribution is centered about the center of mass, indicating a long-lived complex. Above 2.5 eV the distribution slowly moves forward. Most of the available energy goes into internal energy of the products

  9. Cobalt-free nickel-base superalloys

    International Nuclear Information System (INIS)

    Koizumi, Yutaka; Yamazaki, Michio; Harada, Hiroshi

    1979-01-01

    Cobalt-free nickel-base cast superalloys have been developed. Cobalt is considered to be a beneficial element to strengthen the alloys but should be eliminated in alloys to be used for direct cycle helium turbine driven by helium gas from HTGR (high temp. gas reactor). The elimination of cobalt is required to avoid the formation of radioactive 60 Co from the debris or scales of the alloys. Cobalt-free alloys are also desirable from another viewpoint, i.e. recently the shortage of the element has become a serious problem in industry. Cobalt-free Mar-M200 type alloys modified by the additions of 0.15 - 0.2 wt% B and 1 - 1.5 wt% Hf were found to have a creep rupture strength superior or comparable to that of the original Mar-M200 alloy bearing cobalt. The ductility in tensile test at 800 0 C, as cast or after prolonged heating at 900 0 C (the tensile test was done without removing the surface layer affected by the heating), was also improved by the additions of 0.15 - 0.2% B and 1 - 1.5% Hf. The morphology of grain boundaries became intricated by the additions of 0.15 - 0.2% B and 1 - 1.5% Hf, to such a degree that one can hardly distinguish grain boundaries by microscopes. The change in the grain boundary morphology was considered, as suggested previously by one of the authors (M.Y.), to be the reason for the improvements in the creep rupture strength and tensile ductility. (author)

  10. Nanosize boride particles in heat-treated nickel base superalloys

    International Nuclear Information System (INIS)

    Zhang, H.R.; Ojo, O.A.; Chaturvedi, M.C.

    2008-01-01

    Grain boundary microconstituents in aged nickel-based superalloys were studied by transmission electron microscopy techniques. A nanosized M 5 B 3 boride phase, possibly formed by intergranular solute desegregation-induced precipitation, was positively identified. The presence of these intergranular nanoborides provides reasonable clarification of a previously reported reduction of grain boundary liquation temperature during the weld heat affected zone thermal cycle

  11. Multiscale modelling of single crystal superalloys for gas turbine blades

    NARCIS (Netherlands)

    Tinga, T.

    2009-01-01

    Gas turbines are extensively used for power generation and for the propulsion of aircraft and vessels. Their most severely loaded parts, the turbine rotor blades, are manufactured from single crystal nickel-base superalloys. The superior high temperature behaviour of these materials is attributed to

  12. Double minimum creep of single crystal Ni-base superalloys

    Czech Academy of Sciences Publication Activity Database

    WU, X.; Wollgramm, P.; Somsen, C.; Dlouhý, Antonín; Kostka, A.; Eggeler, G.

    2016-01-01

    Roč. 112, JUN (2016), s. 242-260 ISSN 1359-6454 R&D Projects: GA ČR(CZ) GA14-22834S Institutional support: RVO:68081723 Keywords : Single crystal Ni-base superalloys * Primary creep * Transmission electron microscopy * Dislocations * Stacking faults Subject RIV: JG - Metallurgy Impact factor: 5.301, year: 2016

  13. GASN sheets

    International Nuclear Information System (INIS)

    2013-12-01

    This document gathers around 50 detailed sheets which describe and present various aspects, data and information related to the nuclear sector or, more generally to energy. The following items are addressed: natural and artificial radioactive environment, evolution of energy needs in the world, radioactive wastes, which energy for France tomorrow, the consequences in France of the Chernobyl accident, ammunitions containing depleted uranium, processing and recycling of used nuclear fuel, transport of radioactive materials, seismic risk for the basic nuclear installations, radon, the precautionary principle, the issue of low doses, the EPR, the greenhouse effect, the Oklo nuclear reactors, ITER on the way towards fusion reactors, simulation and nuclear deterrence, crisis management in the nuclear field, does nuclear research put a break on the development of renewable energies by monopolizing funding, nuclear safety and security, the plutonium, generation IV reactors, comparison of different modes of electricity production, medical exposure to ionizing radiations, the control of nuclear activities, food preservation by ionization, photovoltaic solar collectors, the Polonium 210, the dismantling of nuclear installations, wind energy, desalination and nuclear reactors, from non-communication to transparency about nuclear safety, the Jules Horowitz reactor, CO 2 capture and storage, hydrogen, solar energy, the radium, the subcontractors of maintenance of the nuclear fleet, biomass, internal radio-contamination, epidemiological studies, submarine nuclear propulsion, sea energy, the Three Mile Island accident, the Chernobyl accident, the Fukushima accident, the nuclear after Fukushima

  14. Factors Affecting Community Participation in O and OD Planning ...

    African Journals Online (AJOL)

    Factors Affecting Community Participation in O and OD Planning and ... great success at start but later dropped in number of cattle taken for dipping. ... and to establish the measures taken by the district leadership in addressing the problems.

  15. Mechanical behaviour of ferritic ODS steels - Temperature dependancy and history

    Czech Academy of Sciences Publication Activity Database

    Fournier, B.; Steckmeyer, A.; Rouffié, A.-L.; Malaplate, J.; Garnier, J.; Ratti, M.; Wident, P.; Ziolek, L.; Tournie, I.; Rabeau, V.; Gentzbittel, J.M.; Kruml, Tomáš; Kuběna, Ivo

    2012-01-01

    Roč. 430, 1-3 (2012), s. 142-149 ISSN 0022-3115 Institutional support: RVO:68081723 Keywords : ODS steels * fatigue * fracture mechanics Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 1.211, year: 2012

  16. Oxide Evolution in ODS Steel Resulting From Friction Stir Welding

    Science.gov (United States)

    2014-06-01

    the SZ on both the AS and RS of 304L stainless steel , from [16]. ...........................................12  Figure 7.  Past research conditions...being done on void swelling and embrittlement effects. Reduced activation ferritic/ martensitic (RAFM) steels and oxide dispersion strengthened (ODS...growth by grain boundary pinning at higher temperatures. Another type of ODS steel is 9-Cr martensitic steel , which is not considered in this research

  17. Photodissociation of the OD radical at 226 and 243 nm

    International Nuclear Information System (INIS)

    Radenovic, Dragana C.; Roij, Andre J.A. van; Chestakov, Dmitri A.; Eppink, Andre T.J.B.; Meulen, J.J. ter; Parker, David H.; Loo, Mark P.J. van der; Groenenboom, Gerrit C.; Greenslade, Margaret E.; Lester, Marsha I.

    2003-01-01

    The photodissociation dynamics of state selected OD radicals has been examined at 243 and 226 nm using velocity map imaging to probe the angle-speed distributions of the D( 2 S) and O( 3 P 2 ) products. Both experiment and complementary first principle calculations demonstrate that photodissociation occurs by promotion of OD from high vibrational levels of the ground X 2 Π state to the repulsive 1 2 Σ - state

  18. High yttria ferritic ODS steels through powder forging

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Deepak [Department of Metallurgical and Materials Engineering, I.I.T-Roorkee, Uttarakhand 247667 (India); Prakash, Ujjwal, E-mail: ujwalfmt@iitr.ac.in [Department of Metallurgical and Materials Engineering, I.I.T-Roorkee, Uttarakhand 247667 (India); Dabhade, Vikram V. [Department of Metallurgical and Materials Engineering, I.I.T-Roorkee, Uttarakhand 247667 (India); Laha, K.; Sakthivel, T. [Mechanical Metallurgy Group, IGCAR, Kalpakkam, Tamilnadu 603102 (India)

    2017-05-15

    Oxide dispersion strengthened (ODS) steels are being developed for future nuclear reactors. ODS Fe-18%Cr-2%W-0.2%Ti steels with 0, 0.35, 0.5, 1 and 1.5% Y{sub 2}O{sub 3} (all compositions in weight%) dispersion were fabricated by mechanical alloying of elemental powders. The powders were placed in a mild steel can and forged in a stream of hydrogen gas at 1473 K. The steels were forged again to final density. The strength of ODS steel increased with yttria content. Though this was accompanied by a decrease in tensile elongation, all the steels showed significant ductility. The ductility in high yttria alloys may be attributed to improved inter-particle bonding between milled powders due to reduction of surface oxides by hydrogen. This may permit development of ODS steels with yttria contents higher than the conventional limit of 0.5%. It is suggested that powder forging is a promising route to fabricate ODS steels with high yttria contents and improved ductility. - Highlights: •ODS steels with yttria contents beyond the conventional limit of 0.5 wt% were fabricated by powder forging in a hydrogen atmosphere. •All the alloys exhibited significant ductility. •This may be attributed to improved inter-particle bonding due to reduction of surface oxides by hydrogen. •Strength in excess of 300 MPa was obtained at 973 K for 0.5%, 1% and 1.5% yttria ODS alloys. •Powder forging is a promising route to fabricate ODS steels and permits development of compositions with up to 1.5% yttria.

  19. OD Matrix Acquisition Based on Mobile Phone Positioning Data

    Directory of Open Access Journals (Sweden)

    Xiaoqing ZUO

    2014-06-01

    Full Text Available Dynamic OD matrix is basic data of traffic travel guidance, traffic control, traffic management and traffic planning, and reflects the basic needs of travelers on the traffic network. With the rising popularity of positioning technology and the communication technology and the generation of huge mobile phone users, the mining and use of mobile phone positioning data, can get more traffic intersections and import and export data. These data will be integrated into obtaining the regional OD matrix, which is bound to bring convenience. In this article, mobile phone positioning data used in the data acquisition of intelligent transportation system, research a kind of regional dynamic OD matrix acquisition method based on the mobile phone positioning data. The method based on purpose of transportation, using time series similarity classification algorithm based on piecewise linear representation of the corner point (CP-PLR, mapping each base station cell to traffic zone of different traffic characteristics, and through a series of mapping optimization of base station cell to traffic zone to realize city traffic zone division based on mobile phone traffic data, on the basis, adjacency matrix chosen as the physical data structure of OD matrix storage, the principle of obtaining regional dynamic OD matrix based on the mobile phone positioning data are expounded, and the algorithm of obtaining regional dynamic OD matrix based on mobile phone positioning data are designed and verified.

  20. Simulation of the BGO-OD experiment at ELSA

    Energy Technology Data Exchange (ETDEWEB)

    Johnstone, Russell [University of Bonn, Physikalisches Institut, Bonn (Germany); Collaboration: BGO-OD-Collaboration

    2011-07-01

    The goal of the BGO Open-Dipole (BGO-OD) project is the systematic investigation of the photoproduction of mesons off the nucleon. These processes are related to the structure of both the mesons and the baryons involved in reactions typical of low-energy hadronic physics. In order to fully understand and accurately interpret the results of the BGO-OD experiment it will be necessary to have a full detector and reaction simulation so that effects from detector resolution and acceptance can be accounted for in the final results. The simulation of the BGO-OD will be be undertaken with the Explora Virtual Monte-Carlo (VMC) software framework. This allows for one common user code to be implemented under Geant4, Geant3 and Fluka. The simulation software is also an analysis tool and such flexibility will be key to an efficient final analysis of the data from the BGO-OD experiment. Presented here are current status of the simulation software for the BGO-OD project and the relevant geometry of the BGO-OD, including the central BGO rugby ball detector with the dual-layer Multiwire Proportional Chambers (MWPCs) and the forward spectrometer, consisting of a large dipole magnet, tracking detectors and the Time-of-Flight walls. Simulation of the magnetic field will also be covered.

  1. Inhibited Aluminization of an ODS FeCr Alloy

    International Nuclear Information System (INIS)

    Vande Put Ep Rouaix, Aurelie; Pint, Bruce A.

    2012-01-01

    Aluminide coatings are of interest for fusion energy applications both for compatibility with liquid Pb-Li and to form an alumina layer that acts as a tritium permeation barrier. Oxide dispersion strengthened (ODS) ferritic steels are a structural material candidate for commercial reactor concepts expected to operate above 600 C. Aluminizing was conducted in a laboratory scale chemical vapor deposition reactor using accepted conditions for coating Fe- and Ni-base alloys. However, the measured mass gains on the current batch of ODS Fe-14Cr were extremely low compared to other conventional and ODS alloys. After aluminizing at two different Al activities at 900 C and at 1100 C, characterization showed that the ODS Fe-14Cr specimens formed a dense, primarily AlN layer that prevented Al uptake. This alloy batch contained a higher (> 5000 ppma) N content than the other alloys coated and this is the most likely reason for the inhibited aluminization. Other factors such as the high O content, small (∼ 140 nm) grain size and Y-Ti oxide nano-clusters in ODS Fe-14Cr also could have contributed to the observed behavior. Examples of typical aluminide coatings formed on conventional and ODS Fe- and Ni-base alloys are shown for comparison.

  2. Modification of the Strength Anisotropy in an Austenitic ODS Steel

    International Nuclear Information System (INIS)

    Kim, T. K.; Jang, J.; Kim, S. H.; Lee, C. B.; Bae, C. S.; Kim, D. H.

    2007-01-01

    Among many candidate alloys for Gen IV reactors, the oxide dispersion strengthened (ODS) alloy is widely considered as a good candidate material for the in-reactor component, like cladding tube. The ODS alloy is well known due to its good high temperature strength, and excellent irradiation resistance. For the previous two decades in the nuclear community, the ODS alloy developments have been mostly focused on the ferritic martensitic (F-M) steel-based ones. On the other hand, the austenitic stainless steels (e.g. 316L or 316LN) have been used as a structural material due to its good high temperature strength and a good compatibility with a media. However, the austenitic stainless steel showed unfavorable characteristics in the dimensional stability under neutron irradiation and cracking behavior with the media. It is thus expected that the austenitic ODS steels restrain the dimension stability under neutron irradiation. However, the ODS alloys usually reveal the anisotropic characteristic in mechanical strength in the hoop and longitudinal directions, which is attributed to the grain morphology strongly developed parallel to the rolling direction with a high aspect ratio. This study focuses on a modification of the strength anisotropy of an austenitic ODS alloy by a recrystallization heat treatment

  3. Precipitation in Powder Metallurgy, Nickel Base Superalloys: Review of Modeling Approach and Formulation of Engineering (Postprint)

    Science.gov (United States)

    2016-12-01

    AFRL-RX-WP-JA-2016-0333 PRECIPITATION IN POWDER- METALLURGY , NICKEL-BASE SUPERALLOYS: REVIEW OF MODELING APPROACH AND FORMULATION OF...PRECIPITATION IN POWDER- METALLURGY , NICKEL- BASE SUPERALLOYS: REVIEW OF MODELING APPROACH AND FORMULATION OF ENGINEERING (POSTPRINT) 5a...and kinetic parameters required for the modeling of γ′ precipitation in powder- metallurgy (PM), nickel-base superalloys are summarized. These

  4. A Comparison of the Plastic Flow Response of a Powder Metallurgy Nickel Base Superalloy (Postprint)

    Science.gov (United States)

    2017-04-01

    AFRL-RX-WP-JA-2017-0225 A COMPARISON OF THE PLASTIC-FLOW RESPONSE OF A POWDER- METALLURGY NICKEL-BASE SUPERALLOY (POSTPRINT) S.L...COMPARISON OF THE PLASTIC-FLOW RESPONSE OF A POWDER- METALLURGY NICKEL-BASE SUPERALLOY (POSTPRINT) 5a. CONTRACT NUMBER IN-HOUSE 5b. GRANT...behavior at hot-working temperatures and strain rates of the powder- metallurgy superalloy LSHR was determined under nominally-isothermal and transient

  5. Recent trends in superalloys research for critical aero-engine components

    Energy Technology Data Exchange (ETDEWEB)

    Remy, Luc [Mine ParisTech, CNRS UMR 7633, 91 - Evry (France). Centre des Materiaux; Guedou, Jean-Yves [Snecma Safran Group, Moissy-Cramayel (France). Materials and Processes Dept.

    2010-07-01

    This paper is a brief survey of common research activity on superalloys for aero-engines between Snecma and Mines ParisTech Centre des Materiaux during recent years. First in disks applications, the development of new powder metallurgy superalloys is shown. Then grain boundary engineering is investigated in a wrought superalloy. Secondly, design oriented research on single crystals blades is shown: a damage model for low cycle fatigue is used for life prediction when cracks initiated at casting pores. The methodology developed for assessing coating life is illustrated for thermal barrier coating deposited on AMI single crystal superalloy. (orig.)

  6. Nanostructure evolution in ODS steels under ion irradiation

    Directory of Open Access Journals (Sweden)

    S. Rogozhkin

    2016-12-01

    In this work, we carried out atom probe tomography (APT and transmission electron microscopy (TEM studies of three different ODS steels produced by mechanical alloying: ODS Eurofer, 13.5Cr ODS and 13.5Cr-0.3Ti ODS. These materials were investigated after irradiation with Fe (5.6MeV or Ti (4.8MeV ions up to 1015ion/cm2 and part of them up to 3×1015ion/cm2. In all cases, areas for TEM investigation were cut at a depth of ∼ 1.3µm from the irradiated surface corresponding to the peak of the radiation damage dose. It was shown that after irradiation at RT and at 300°С the number density of oxide particles in all the samples grew up. Meanwhile, the fraction of small particles in the size distribution has increased. APT revealed an essential increase in nanoclusters number and a change of their chemical composition at the same depth. The nanostructure was the most stable in 13.5Cr-0.3Ti ODS irradiated at 300°С: the increase of the fraction of small oxides was minimal and no change of nanocluster chemical composition was detected.

  7. [Development and integration of the Oncological Documentation System ODS].

    Science.gov (United States)

    Raab, G; van Den Bergh, M

    2001-08-01

    To simplify clinical routine and to improve medical quality without exceeding the existing resources. Intensifying communication and cooperation between all institutions of patients' health care. The huge amount of documentation work of physicians can no longer be done without modern tools of paperless data processing. The development of ODS was a tight cooperation between physician and technician which resulted in a mutual understanding and led to a high level of user convenience. - At present all cases of gynecology, especially gynecologic oncology can be documented and processed by ODS. Users easily will adopt the system as data entry within different program areas follows the same rules. In addition users can choose between an individual input of data and assistants guiding them through highly specific areas of documentation. ODS is a modern, modular structured and very fast multiuser database environment for in- and outpatient documentation. It automatically generates a lot of reports for clinical day to day business. Statistical routines will help the user reflecting his work and its quality. Documentation of clinical trials according to the GCP guidelines can be done by ODS using the internet or offline datasharing. As ODS is the synthesis of a computer based patient administration system and an oncological documentation database, it represents the basis for the construction of the electronical patient chart as well as the digital documentation of clinical trials. The introduction of this new technology to physicians and nurses has to be done slowly and carefully, in order to increase motivation and to improve the results.

  8. High yttria ferritic ODS steels through powder forging

    Science.gov (United States)

    Kumar, Deepak; Prakash, Ujjwal; Dabhade, Vikram V.; Laha, K.; Sakthivel, T.

    2017-05-01

    Oxide dispersion strengthened (ODS) steels are being developed for future nuclear reactors. ODS Fe-18%Cr-2%W-0.2%Ti steels with 0, 0.35, 0.5, 1 and 1.5% Y2O3 (all compositions in weight%) dispersion were fabricated by mechanical alloying of elemental powders. The powders were placed in a mild steel can and forged in a stream of hydrogen gas at 1473 K. The steels were forged again to final density. The strength of ODS steel increased with yttria content. Though this was accompanied by a decrease in tensile elongation, all the steels showed significant ductility. The ductility in high yttria alloys may be attributed to improved inter-particle bonding between milled powders due to reduction of surface oxides by hydrogen. This may permit development of ODS steels with yttria contents higher than the conventional limit of 0.5%. It is suggested that powder forging is a promising route to fabricate ODS steels with high yttria contents and improved ductility.

  9. Microstructural Characterization and Modeling of SLM Superalloy 718

    Science.gov (United States)

    Smith, Tim M.; Sudbrack, Chantal K.; Bonacuse, Pete; Rogers, Richard

    2017-01-01

    Superalloy 718 is an excellent candidate for selective laser melting (SLM) fabrication due to a combination of excellent mechanical properties and workability. Predicting and validating the microstructure of SLM-fabricated Superalloy 718 after potential post heat-treatment paths is an important step towards producing components comparable to those made using conventional methods. At present, obtaining accurate volume fraction and size measurements of gamma-double-prime, gamma-prime and delta precipitates has been challenging due to their size, low volume fractions, and similar chemistries. A technique combining high resolution distortion corrected SEM imaging and with x-ray energy dispersive spectroscopy has been developed to accurately and independently measure the size and volume fractions of the three precipitates. These results were further validated using x-ray diffraction and phase extraction methods and compared to the precipitation kinetics predicted by PANDAT and JMatPro. Discrepancies are discussed in context of materials properties, model assumptions, sampling, and experimental errors.

  10. Analysis of laser beam weldability of Inconel 738 superalloy

    International Nuclear Information System (INIS)

    Egbewande, A.T.; Buckson, R.A.; Ojo, O.A.

    2010-01-01

    The susceptibility of pre-weld heat treated laser beam welded IN 738 superalloy to heat affected zone (HAZ) cracking was studied. A pre-weld heat treatment that produced the minimal grain boundary liquation resulted in a higher level of cracking compared to those with more intergranular liquation. This deviation from the general expectation of influence of intergranular liquation extent on HAZ microfissuring is attributable to the reduction in the ability of the base alloy to accommodate welding tensile stress that accompanied a pre-weld heat treatment condition designed to minimize intergranular liquation. Furthermore, in contrast to what has been generally reported in other nickel-based superalloys, a decrease in laser welding speed resulted in increased HAZ cracking in the IN 738, which can be attributed to exacerbated process instability at lower welding speeds.

  11. Phase Stability of a Powder Metallurgy Disk Superalloy

    Science.gov (United States)

    Gabb, Timothy P.; Gayda, John; Kantzos, P.; Telesman, Jack; Gang, Anita

    2006-01-01

    Advanced powder metallurgy superalloy disks in aerospace turbine engines now entering service can be exposed to temperatures approaching 700 C, higher than those previously encountered. They also have higher levels of refractory elements, which can increase mechanical properties at these temperatures but can also encourage phase instabilities during service. Microstructural changes including precipitation of topological close pack phase precipitation and coarsening of existing gamma' precipitates can be slow at these temperatures, yet potentially significant for anticipated disk service times exceeding 1,000 h. The ability to quantify and predict such potential phase instabilities and degradation of capabilities is needed to insure structural integrity and air worthiness of propulsion systems over the full life cycle. A prototypical advanced disk superalloy was subjected to high temperature exposures, and then evaluated. Microstructural changes and corresponding changes in mechanical properties were quantified. The results will be compared to predictions of microstructure modeling software.

  12. Microstructure evolution during dynamic recrystallization of hot deformed superalloy 718

    International Nuclear Information System (INIS)

    Wang, Y.; Shao, W.Z.; Zhen, L.; Zhang, X.M.

    2008-01-01

    Microstructure evolution during dynamic recrystallization (DRX) of superalloy 718 was studied by optical microscope and electron backscatter diffraction (EBSD) technique. Compression tests were performed at different strains at temperatures from 950 deg. C to 1120 deg. C with a strain rate of 10 -1 s -1 . Microstructure observations show that the recrystallized grain size as well as the fraction of new grains increases with the increasing temperature. A power exponent relationship is obtained between the dynamically recrystallized grain size and the peak stress. It is found that different nucleation mechanisms for DRX are operated in hot deformed superalloy 718, which is closely related to deformation temperatures. DRX nucleation and development are discussed in consideration of subgrain rotation or twinning taking place near the original grain boundaries. Particular attention is also paid to the role of continuous dynamic recrystallization (CDRX) at both higher and lower temperatures

  13. Surface modification, microstructure and mechanical properties of investment cast superalloy

    OpenAIRE

    M. Zielińska; K. Kubiak; J. Sieniawski

    2009-01-01

    Purpose: The aim of this work is to determine physical and chemical properties of cobalt aluminate (CoAl2O4) modifiers produced by different companies and the influence of different types of modifiers on the grain size, the microstructure and mechanical properties of high temperature creep resisting superalloy René 77.Design/methodology/approach: The first stage of the research work took over the investigations of physical and chemical properties of cobalt aluminate manufactured by three diff...

  14. Powder-metallurgy superalloy strengthened by a secondary gamma phase.

    Science.gov (United States)

    Kotval, P. S.

    1971-01-01

    Description of experiments in which prealloyed powders of superalloy compositions were consolidated by extrusion after the strengthening by precipitation of a body-centered tetragonal gamma secondary Ni3 Ta phase. Thin foil electron microscopy showed that the mechanical properties of the resultant powder-metallurgy product were correlated with its microstructure. The product exhibited high strength at 1200 F without loss of ductility, after thermomechanical treatment and aging.

  15. Fatigue characteristics of ODS surface treated Zircaloy-4

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sun Han; Jung, Yan gIl; Park, Dong Jun; Park, Jung Hwan; Kim, Hyun Gil; Yang, Jae Ho; Koo, Yang Hyun [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    Various accident tolerant fuel (ATF) cladding concepts are considered and have being developed to increase the oxidation resistance and ballooning/ rupture resistance of current Zr-based cladding material under accident conditions. One concept is to form an oxidation-resistant layer on Zr cladding surface. The other is to increase high temperature mechanical strength of Zr tube. The oxide dispersion strengthened (ODS) zirconium was proposed to increase the strength of the Zr-based alloy up to high temperatures. ODS treatment is a way of improve the high temperature- oxidation resistant and mechanical stress by disperse the hardened particles inside of metal to interrupt the movement of the electric potential. In this study, the accident tolerance improved zirconium alloy by the ODS surface treatment was evaluated for the fatigue characteristics which is one of the significant items of the integrity assessment.

  16. Void formation in ODS EUROFER produced by hot isostatic pressing

    International Nuclear Information System (INIS)

    Ortega, Y.; Monge, M.A.; Castro, V. de; Munoz, A.; Leguey, T.; Pareja, R.

    2009-01-01

    Positron annihilation experiments were performed on oxide dispersion strengthened (ODS) and non-ODS EUROFER prepared by mechanical alloying and hot isostatic pressing. The results revealed the presence of small voids in these materials in the as-HIPed conditions. Their evolution under isochronal annealing experiments was investigated. The coincidence Doppler broadening spectra of ODS EUROFER exhibited a characteristic signature attributed to positron annihilation in Ar-decorated voids at the oxide particle/matrix interfaces. The variation of the positron annihilation parameters with the annealing temperature showed three stages: up to 623 K, between 823 and 1323 K, and above 1323 K. In the temperature range 823-1323 K void coarsening had effect. Above 1323 K some voids annealed out, but others, associated to oxide particles and small precipitates, survived to annealing at 1523 K. Transmission electron microscopy observations were also performed to verify the characteristics of the surviving defects after annealing at 1523 K.

  17. Void formation in ODS EUROFER produced by hot isostatic pressing

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, Y. [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain)], E-mail: yanicet@fis.ucm.es; Monge, M.A. [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain); Castro, V. de [Department of Materials, University of Oxford, Oxford OX1 3PH (United Kingdom); Munoz, A.; Leguey, T.; Pareja, R. [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain)

    2009-04-30

    Positron annihilation experiments were performed on oxide dispersion strengthened (ODS) and non-ODS EUROFER prepared by mechanical alloying and hot isostatic pressing. The results revealed the presence of small voids in these materials in the as-HIPed conditions. Their evolution under isochronal annealing experiments was investigated. The coincidence Doppler broadening spectra of ODS EUROFER exhibited a characteristic signature attributed to positron annihilation in Ar-decorated voids at the oxide particle/matrix interfaces. The variation of the positron annihilation parameters with the annealing temperature showed three stages: up to 623 K, between 823 and 1323 K, and above 1323 K. In the temperature range 823-1323 K void coarsening had effect. Above 1323 K some voids annealed out, but others, associated to oxide particles and small precipitates, survived to annealing at 1523 K. Transmission electron microscopy observations were also performed to verify the characteristics of the surviving defects after annealing at 1523 K.

  18. Zircaloy cladding ID/OD oxidation studies. Final report

    International Nuclear Information System (INIS)

    Westerman, R.E.; Hesson, G.M.

    1977-11-01

    The ID/OD oxide ratio that forms on Zircaloy tubing at temperatures relevant to postulated LOCA conditions was measured as a function of time, temperature, and distance from the rupture. The average ratio at the rupture position was less than unity, and decreased with decreasing test time and increasing distance from the point of rupture. The maximum observed ID/OD oxide ratio was 1.4. Ratios in excess of unity were typically found to be a consequence of the OD oxide being thinner than would have been anticipated from the nominal test conditions. Confirmatory data were also obtained on the isothermal oxidation kinetics of Zircaloy. These data are in good agreement with those obtained by other investigators and confirm the conservative nature of the Baker-Just equation that is required for use in licensing calculations

  19. STS-74 view of ODS from Payload Changout Room

    Science.gov (United States)

    1995-01-01

    Workers at Launch Pad 39A are preparing to close the payload bay doors on the Space Shuttle Atlantis for its upcoming launch on Mission STS-74 and the second docking with the Russian Space Station Mir. Uppermost in the payload bay is the Orbiter Docking System (ODS), which also flew on the first docking flight between the Space Shuttle and MIR. Lowermost is the primary payload of STS-74, the Russian-built Docking Module. During the mission, the Docking Module will first be attached to ODS and then to Mir. It will be left attached to Mir to become a permanent extension that will afford adequate clearance between the orbiter and the station during future dockings. At left in the payload bay, looking like a very long pole, is the Canadian-built Remote Manipulator System arm that will be used by the crew to hoist the Docking Module and attach it to the ODS.

  20. The dynamics of the reaction of 16O(1D)+D218O→16OD+18OD

    International Nuclear Information System (INIS)

    Guillory, W.A.; Gericke, K.H.; Comes, F.J.

    1983-01-01

    The detailed energy partitioning in the reaction of a metastable oxygen atom O( 1 D) with D 2 O proceeding to two OD molecules has been studied. In order to distinguish the product state distribution between the two chemically identical product molecules OD, the oxygen atom in the heavy water molecule was labeled isotopically. The use of spectroscopic methods allows a complete analysis of the products' state distribution including such fine details as the distribution of the different #betta# components and of the electron spin. The vibrational energy is almost exclusively channeled into the new ( 16 OD) bond, whereas the original ( 18 OD) bond is produced (>90%) in the ground vibrational state. Both OD radicals show a broad rotational excitation and the rotational energy is equally partitioned among the two bonds. The energy distribution over the rovibrational levels strongly reflects the influence of coincident product molecules emerging from this chemical reaction. The reaction is very direct and must proceed on a time scale which does not allow for efficient energy transfer into all the available phase space

  1. Evaluation of cost reduction method for manufacturing ODS ferritic claddings

    International Nuclear Information System (INIS)

    Fujiwara, Masayuki; Mizuta, Shunji; Ukai, Shigeharu

    2000-04-01

    For evaluating the fast reactor system technology, it is important to evaluate the practical feasibility of ODS ferritic claddings, which is the most promising materials to attain the goal of high coolant temperature and more than 150 GWd/t. Based on the results of their technology development, mass production process with highly economically benefit as well as manufacturing cost estimation of ODS ferritic claddings were preliminarily conducted. From the view point of future utility scale, the cost for manufacturing mother tubes has a dominant factor in the total manufacturing cost. The method to reduce the cost of mother tube manufacturing was also preliminarily investigated. (author)

  2. The filler powders laser welding of ODS ferritic steels

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Shenyong, E-mail: s_y_liang@126.com; Lei, Yucheng; Zhu, Qiang

    2015-01-15

    Laser welding was performed on Oxide Dispersion Strengthened (ODS) ferritic steel with the self-designed filler powders. The filler powders were added to weld metal to produce nano-particles (Y–M–O and TiC), submicron particles (Y–M–O) and dislocation rings. The generated particles were evenly distributed in the weld metal and their forming mechanism and behavior were analyzed. The results of the tests showed that the nano-particles, submicron particles and dislocation rings were able to improve the micro-hardness and tensile strength of welded joint, and the filler powders laser welding was an effective welding method of ODS ferritic steel.

  3. Rafting in single crystal nickel-base superalloys – An overview

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    Page 1 ... aircraft engines as well as land-based power generation applications. Microstruc- ture and high temperature mechanical properties are the major factors controlling the performance of SX ... Single crystal (SX) superalloys are a group of nickel-base superalloys. They exhibit superior high temperatur mechanical ...

  4. Erosion–corrosion behaviour of Ni-based superalloy Superni-75 in ...

    Indian Academy of Sciences (India)

    microscopy/energy-dispersive analysis (SEM/EDAX) and electron probe micro ... gas turbines and they have designated this alloy as superalloy Superni-75. ... The nickel-based superalloy Superni-75 (19·5Cr-3Fe-0·3Ti-0·1C- Balance Ni) was ...

  5. The Mechanical Properties of Candidate Superalloys for a Hybrid Turbine Disk

    Science.gov (United States)

    Gabb, Timothy P.; MacKay, Rebecca A.; Draper, Susan L.; Sudbrack, Chantal K.; Nathal, Michael V.

    2013-01-01

    The mechanical properties of several cast blade superalloys and one powder metallurgy disk superalloy were assessed for potential use in a dual alloy hybrid disk concept of joined dissimilar bore and web materials. Grain size was varied for each superalloy class. Tensile, creep, fatigue, and notch fatigue tests were performed at 704 to 815 degC. Typical microstructures and failure modes were determined. Preferred materials were then selected for future study as the bore and rim alloys in this hybrid disk concept. Powder metallurgy superalloy LSHR at 15 micron grain size and single crystal superalloy LDS-1101+Hf were selected for further study, and future work is recommended to develop the hybrid disk concept.

  6. High temperature oxidation and corrosion behavior of Ni-base superalloy in He environment

    International Nuclear Information System (INIS)

    Lee, Gyoeng Geun; Park, Ji Yeon; Jung, Su jin

    2010-11-01

    Ni-base superalloy is considered as a IHX (Intermediate Heat Exchanger) material for VHTR (Very High Temperature Gas-Cooled Reactor). The helium environment in VHTR contains small amounts of impure gases, which cause oxidation, carburization, and decarburization. In this report, we conducted the literature survey about the high temperature behavior of Ni-base superalloys in air and He environments. The basic information of Ni-base superalloy and the basic metal-oxidation theory were briefly stated. The He effect on the corrosion of Ni-base superalloy was also summarized. This works would provide a brief suggestion for the next research topic for the application of Ni-base superalloy to VHTR

  7. Behaviour of new ODS alloys under single and multiple deformation

    Czech Academy of Sciences Publication Activity Database

    Mašek, B.; Khalaj, O.; Nový, Z.; Kubina, T.; Jirková, H.; Svoboda, Jiří; Stadler, C.

    2016-01-01

    Roč. 50, č. 6 (2016), s. 891-898 ISSN 1580-2949 R&D Projects: GA ČR(CZ) GA14-24252S Institutional support: RVO:68081723 Keywords : ODS alloys * composite * steel * Fe-Al Subject RIV: JI - Composite Materials Impact factor: 0.436, year: 2016

  8. Reactions of Three Lactones with Cl, OD, and O3

    DEFF Research Database (Denmark)

    Ausmeel, Stina; Andersen, C.; Nielsen, Ole John

    2017-01-01

    -methyl-γ-crotonolactone (3M-2(5H)-F) with Cl, OD, and O3 were investigated in a static chamber at 700 Torr and 298 ± 2 K. The relative rate method was used to determine kGVL+Cl = (4.56 ± 0.51) × 10-11, kGVL+OD = (2.94 ± 0.41) × 10-11, k2(5H)-F+Cl = (2.94 ± 0.41) × 10-11, k2(5H)-F+OD = (4.06 ± 0.073) × 10-12, k3M-2(5H......)-F+Cl = (16.1 ± 1.8) × 10-11, and k3M-2(5H)-F+OD = (12.6 ± 0.52) × 10-12, all rate coefficients in units of cm3 molecule-1 s-1. An absolute rate method was used to determine k2(5H)-F+O3 = (6.73 ± 0.18) × 10-20 and k3M-2(5H)-F+O3 = (5.42 ± 1.23) × 10-19 in units of cm3 molecule-1 s-1. Products were identified...

  9. High temperature deformation mechanisms in the 14% Cr ODS alloy

    Czech Academy of Sciences Publication Activity Database

    Šiška, Filip; Stratil, Luděk; Hadraba, Hynek; Fintová, Stanislava; Kuběna, Ivo; Záležák, Tomáš; Bártková, Denisa

    2017-01-01

    Roč. 689, MAR (2017), s. 34-39 ISSN 0921-5093 R&D Projects: GA ČR(CZ) GA14-25246S; GA ČR GJ15-21292Y Institutional support: RVO:68081723 Keywords : ODS steel * Plastic ity * Stress relaxation * Dislocations Subject RIV: JG - Metallurgy OBOR OECD: Materials engineering Impact factor: 3.094, year: 2016

  10. Hydrogen Transport and Trapping in ODS-EUROFER

    International Nuclear Information System (INIS)

    Esteban, G.A.; Pena, A.; Legarda, F.; Lindau, R.

    2006-01-01

    Oxide Dispersion Strengthened (ODS) EUROFER is a candidate structural material to be used in the design of several blanket options [R. Lindau et al. Fusion Eng. Des. 75 - 79 (2005) 989]. This type of material allows higher temperature performance (650 o C) than standard RAFM steels and shows improved mechanical properties like superior tensile and creep properties in comparison to the base material EUROFER [R. Lindau, A. Moeslang, M. Schirra, P. Schlossmacher, M. Klimenkov, J. Nucl. Mater. 307-311 (2002) 769]. Together with mechanical and activation properties, the characterization of hydrogen isotope transport properties in any fusion technology material is compulsory because they affect important issues of the blanket concept using a specific collection of materials, such as the fuel economy, plasma stability and the radiological security of the fusion reactor. The hydrogen interaction properties of permeability, diffusivity and Sieverts' constant in ODS-EUROFER are experimentally evaluated by using the gas evolution permeation technique. The results are analysed together with the properties of the base material in order to study the influence of the particular microstructure of ODS in the hydrogen transport. Higher permeability of hydrogen in ODS-EUROFER has been obtained in comparison to the base material EUROFER. The effect of trapping showing a high time lag for non steady-state permeation has been noticed in the low temperature range. The trapping phenomena is identified to be the cause of such effect and the presence of nanoparticles of Yttria the reason for the source of additional trapping sites. The concluding remark is a decrease in the diffusivity and an increase in the solubility of hydrogen in the material at low temperature. All the hydrogen transport parameters obtained for ODS-EUROFER are compared to the properties of base material and available data corresponding to other RAFM steels of the same kind. (author)

  11. 75 FR 9232 - Office of Dietary Supplements (ODS) 2010-2014 Strategic Plan

    Science.gov (United States)

    2010-03-01

    ... completed a strategic planning process resulting in the development of the ODS Strategic Plan for 2010-2014, entitled Strengthening Knowledge and Understanding of Dietary Supplements. The strategic plan is available... Supplements (ODS) 2010-2014 Strategic Plan ACTION: Notice of availability of the ODS Strategic Plan for 2010...

  12. 46 CFR 280.3 - Standards governing award of an ODS agreement.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Standards governing award of an ODS agreement. 280.3 Section 280.3 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION REGULATIONS AFFECTING... LINER OPERATORS § 280.3 Standards governing award of an ODS agreement. No ODS agreement, including any...

  13. Innovative technologies for powder metallurgy-based disk superalloys: Progress and proposal

    Science.gov (United States)

    Chong-Lin, Jia; Chang-Chun, Ge; Qing-Zhi, Yan

    2016-02-01

    Powder metallurgy (PM) superalloys are an important class of high temperature structural materials, key to the rotating components of aero engines. In the purview of the present challenges associated with PM superalloys, two novel approaches namely, powder preparation and the innovative spray-forming technique (for making turbine disk) are proposed and studied. Subsequently, advanced technologies like electrode-induction-melting gas atomization (EIGA), and spark-plasma discharge spheroidization (SPDS) are introduced, for ceramic-free superalloy powders. Presently, new processing routes are sought after for preparing finer and cleaner raw powders for disk superalloys. The progress of research in spray-formed PM superalloys is first summarized in detail. The spray-formed superalloy disks specifically exhibit excellent mechanical properties. This paper reviews the recent progress in innovative technologies for PM superalloys, with an emphasis on new ideas and approaches, central to the innovation driving techniques like powder processing and spray forming. Project supported by the National Natural Science Foundation of China (Grant Nos. 50974016 and 50071014).

  14. Microstructural and mechanical characterization of injection molded 718 superalloy powders

    Energy Technology Data Exchange (ETDEWEB)

    Özgün, Özgür [Bingol University, Faculty of Engineering and Architecture, Mechanical Eng. Dep., 12000 Bingol (Turkey); Gülsoy, H. Özkan, E-mail: ogulsoy@marmara.edu.tr [Marmara University, Technology Faculty, Metallurgy and Materials Eng. Dep., 34722 Istanbul (Turkey); Yılmaz, Ramazan [Sakarya University, Technology Faculty, Metallurgy and Materials Eng. Dep., 54187 Sakarya (Turkey); Fındık, Fehim [Sakarya University, Technology Faculty, Metallurgy and Materials Eng. Dep., 54187 Sakarya (Turkey) and International University of Sarajevo, Faculty of Engineering and Natural Sciences, Department of Mechanical Engineering, 71000 Sarajevo, Bosnia and Herzegovina (Bosnia and Herzegowina)

    2013-11-05

    Highlights: •Microstructural and mechanical properties of injection molded Nickel 718 superalloy were studied. •The maximum sintered density achieved this study was 97.3% at 1290 °C for 3 hours. •Tensile strength of 1022 MPa and elongation of 5.3% were achieved for sintered-heat treated samples. -- Abstract: This study concerns with the determination of optimum production parameters for injection molding 718 superalloy parts. And at the same time, microstructural and mechanical characterization of these produced parts was also carried out. At the initial stage, 718 superalloy powders were mixed with a multi-component binder system for preparing feedstock. Then the prepared feedstock was granulated and shaped by injection molding. Following this operation, the shaped samples were subjected to the debinding process. These samples were sintered at different temperatures for various times. Samples sintered under the condition that gave way to the highest relative density (3 h at 1290 °C) were solution treated and aged respectively. Sintered, solution treated and aged samples were separately subjected to microstructural and mechanical characterization. Microstructural characterization operations such as X-ray diffraction, optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) and elemental analysis showed that using polymeric binder system led to plentiful carbide precipitates to be occurred in the injection molded samples. It is also observed that the volume fractions of the intermetallic phases (γ′ and γ″) obtained by aging treatment were decreased due to the plentiful carbide precipitation in the samples. Mechanical characterization was performed by hardness measurements and tensile tests.

  15. Hot deformation behavior of delta-processed superalloy 718

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y., E-mail: wangyanhit@yahoo.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); School of Aeronautics and Astronautics, Central South University, Changsha 410083 (China); Shao, W.Z.; Zhen, L.; Zhang, B.Y. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2011-03-25

    Research highlights: {yields} The peak stress for hot deformation can be described by the Z parameter. {yields} The grain size of DRX was inversely proportional to the Z parameter. {yields} The dissolution of {delta} phases was greatly accelerated under hot deformation. {yields}The {delta} phase stimulated nucleation can serve as the main DRX mechanism. - Abstract: Flow stress behavior and microstructures during hot compression of delta-processed superalloy 718 at temperatures from 950 to 1100 deg. C with strain rates of 10{sup -3} to 1 s{sup -1} were investigated by optical microscopy (OM), electron backscatter diffraction (EBSD) technique and transmission electron microscopy (TEM). The relationship between the peak stress and the deformation conditions can be expressed by a hyperbolic-sine type equation. The activation energy for the delta-processed superalloy 718 is determined to be 467 kJ/mol. The change of the dominant deformation mechanisms leads to the decrease of stress exponent and the increase of activation energy with increasing temperature. The dynamically recrystallized grain size is inversely proportional to the Zener-Hollomon (Z) parameter. It is found that the dissolution rate of {delta} phases under hot deformation conditions is much faster than that under static conditions. Dislocation, vacancy and curvature play important roles in the dissolution of {delta} phases. The main nucleation mechanisms of dynamic recrystallization (DRX) for the delta-processed superalloy 718 include the bulging of original grain boundaries and the {delta} phase stimulated DRX nucleation, which is closely related to the dissolution behavior of {delta} phases under certain deformation conditions.

  16. Development of ODS-Fe{sub 3}Al alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wright, I.G.; Pint, B.A.; Tortorelli, P.F.; McKamey, C.G. [Oak Ridge National Lab., TN (United States)

    1997-12-01

    The overall goal of this program is to develop an oxide dispersion-strengthened (ODS) version of Fe{sub 3}Al that has sufficient creep strength and resistance to oxidation at temperatures in the range 1000 to 1200 C to be suitable for application as heat exchanger tubing in advanced power generation cycles. The main areas being addressed are: (a) alloy processing to achieve the desired alloy grain size and shape, and (b) optimization of the oxidation behavior to provide increased service life compared to semi-commercial ODS-FeCrAl alloys intended for the same applications. The recent studies have focused on mechanically-alloyed powder from a commercial alloy vendor. These starting alloy powders were very clean in terms of oxygen content compared to ORNL-produced powders, but contained similar levels of carbon picked up during the milling process. The specific environment used in milling the powder appears to exert a considerable influence on the post-consolidation recrystallization behavior of the alloy. A milling environment which produced powder particles having a high surface carbon content resulted in a consolidated alloy which readily recrystallized, whereas powder with a low surface carbon level after milling resulted in no recrystallization even at 1380 C. A feature of these alloys was the appearance of voids or porosity after the recrystallization anneal, as had been found with ORNL-produced alloys. Adjustment of the recrystallization parameters did not reveal any range of conditions where recrystallization could be accomplished without the formation of voids. Initial creep tests of specimens of the recrystallized alloys indicated a significant increase in creep strength compared to cast or wrought Fe{sub 3}Al, but the specimens failed prematurely by a mechanism that involved brittle fracture of one of the two grains in the test cross section, followed by ductile fracture of the remaining grain. The reasons for this behavior are not yet understood. The

  17. Study of the oxidation kinetics of the MA 956 superalloy

    International Nuclear Information System (INIS)

    Garcia-Alonso, M.C.; Gonzalez-Carrasco, J.L.; Escudero, M.L.

    1998-01-01

    This work deals with the oxidation kinetics of the MA 956 superalloy in the temperature range of 800-1,200 degree centigree for up to 200 h exposure. During oxidation the alloy develops a fine, compact and very well adhered α-alumina layer, the thickness of which increases with increasing time and temperature. The oxidation kinetics obeys a sub parabolic type behaviour. The scale growth seems to occur by two different oxidation mechanisms; above 1,050 degree centigree, the oxidation process would be controlled by α-alumina, and below 900 degree centigree by γ-alumina. (Author) 17 refs

  18. Oxidation behavior and compositional analysis of aluminized superalloy

    International Nuclear Information System (INIS)

    Khalid, F.A.; Nawaz, F.

    2003-01-01

    The high temperature oxidation behavior of superalloy specimens used for the manufacture of turbine blades has been examined using scanning electron microscopy (SEM) and fine-probe spot and line scan EDS microanalysis techniques. The performance of aluminized coating applied to the specimens has also been examined. It was observed that complex oxides are formed in both coated and uncoated specimens. However the coated specimens revealed a greater stability of gamma phase and integrity of aluminized coating as compared with uncoated specimens. The microchemical and microstructural changes that occurred during oxidation have been analyzed to examine characteristics of oxide layers. (author)

  19. Microstructural causes of negative creep in cast superalloys

    International Nuclear Information System (INIS)

    Frank, G.

    1990-01-01

    The dissertation examines by means of microstructural investigations and modelling calculations two types of superalloys: the nickel-base cast alloy IN 738 LC (γ'-hardened, containing MC and M 23 C 6 carbides), and the cobalt-base cast alloy FSX 414 (containing M 23 C 6 carbides, solid solution-hardened). The task was to determine the causes of microstructural volume contraction, in order to improve and facilitate explanation and extrapolation of the materials' long-term behaviour at high temperatures, and to derive if possible information on appropriate measures preventing negative creep, which may lead to critical damage of bolted joints, for instance. (orig./MM) [de

  20. High temperature deformation mechanisms of L12-containing Co-based superalloys

    Science.gov (United States)

    Titus, Michael Shaw

    Ni-based superalloys have been used as the structural material of choice for high temperature applications in gas turbine engines since the 1940s, but their operating temperature is becoming limited by their melting temperature (Tm =1300degrees C). Despite decades of research, no viable alternatives to Ni-based superalloys have been discovered and developed. However, in 2006, a ternary gamma' phase was discovered in the Co-Al-W system that enabled a new class of Co-based superalloys to be developed. These new Co-based superalloys possess a gamma-gamma' microstructure that is nearly identical to Ni-based superalloys, which enables these superalloys to achieve extraordinary high temperature mechanical properties. Furthermore, Co-based alloys possess the added benefit of exhibiting a melting temperature of at least 100degrees C higher than commercial Ni-based superalloys. Superalloys used as the structural materials in high pressure turbine blades must withstand large thermomechanical stresses imparted from the rotating disk and hot, corrosive gases present. These stresses induce time-dependent plastic deformation, which is commonly known as creep, and new superalloys must possess adequate creep resistance over a broad range of temperature in order to be used as the structural materials for high pressure turbine blades. For these reasons, this research focuses on quantifying high temperature creep properties of new gamma'-containing Co-based superalloys and identifying the high temperature creep deformation mechanisms. The high temperature creep properties of new Co- and CoNi-based alloys were found to be comparable to Ni-based superalloys with respect to minimum creep rates and creep-rupture lives at 900degrees C up to the solvus temperature of the gamma' phase. Co-based alloys exhibited a propensity for extended superlattice stacking fault formation in the gamma' precipitates resulting from dislocation shearing events. When Ni was added to the Co-based compositions

  1. Zaburzenia odżywiania – dylematy diagnozy

    Directory of Open Access Journals (Sweden)

    Maciej Wojciech Pilecki

    2014-06-01

    Full Text Available Celem badania było przedstawienie dylematów dotyczących diagnozy zaburzeń odżywiania się na przykładzie alternatywnego do kryteriów klinicznych podziału grupy dziewcząt z rozpoznaniem tych zaburzeń, uwzględniającego wyniki kwestionariuszy samooceny. Badaniem objęto 116 dziewcząt z rozpoznaniem któregoś z zaburzeń odżywiania się według DSM-IV, konsultowanych po raz pierwszy w latach 2002–2004 w ambulatorium Oddziału Klinicznego Psychiatrii Dzieci i Młodzieży Szpitala Uniwersyteckiego w Krakowie. Z uwagi na ograniczenia statystyczne modelu jedynie zmienne zależne, takie jak: samoocena obecności objawów depresyjnych (Kwestionariusz Depresji Becka, BDI, samoocena obecności problemów z odżywianiem się (Kwestionariusz Postaw wobec Odżywiania, EAT26, obraz siebie (Ja Społeczne Kwestionariusza Obrazu Siebie Offera, JaSpoł QSIA i relacje rodzinne (skala Intymności Skali Rodziny Pochodzenia, INT FOS, zostały poddane analizie skupień metodą k-średnich. Przeprowadzone analizy doprowadziły do wyłonienia pięciu skupień niepokrywających się z podziałem na poszczególne diagnozy kliniczne. Wszystkie skupienia różnią się wynikami tworzących je skal kwestionariuszowych. Pierwsze skupienie okazało się charakteryzować osoby o niskim w swojej ocenie nasileniu występowania problemów z odżywianiem się i depresyjności oraz korzystnym obrazie swojego funkcjonowania społecznego i relacji rodzinnych. Zależność obserwowana w skupieniu 5. była odwrotna. Przeważająca liczba pacjentek w skupieniu 1. miała rozpoznaną anoreksję restrykcyjną, a w skupieniu 5. bulimię. Najbardziej odmienne od pozostałych okazało się skupienie 3. Pozytywnemu obrazowi siebie, relacji rodzinnych w badanych obszarach towarzyszyło duże nasilenie występowania problemów z odżywianiem się i niskie depresyjności w samoocenie. Otrzymane wyniki wskazują, iż podział kliniczny zaburzeń odżywania się proponowany w ICD i

  2. Casting technology for ODS steels - the internal oxidation approach

    Science.gov (United States)

    Miran, S.; Franke, P.; Möslang, A.; Seifert, H. J.

    2017-07-01

    The formation of stainless ODS steel by internal oxidation of as-cast steel has been investigated. An alloy (Fe-16Cr-0.2Al-0.05Y, wt.%) was embedded in a (VO/V2O3) powder mixture serving as an oxygen activity buffer and heat treated at 1450 °C for 20 h. After this procedure no oxide scale was present on the surface of the sample but a zone of internal oxidation with a depth of about 2000 μm was formed in its interior. The precipitates within this zone consisted of two types of oxides. Discrete aluminium oxide particles with a size of a few micrometres were formed in outer regions of the specimen. Finer aluminium-yttrium oxides with a size of some hundred nanometres were mainly precipitated in inner regions of the sample. The results can be considered as a promising step towards an alternative production route for ODS steels.

  3. High temperature oxidation test of oxide dispersion strengthened (ODS) steel claddings

    International Nuclear Information System (INIS)

    Narita, Takeshi; Ukai, Shigeharu; Kaito, Takeji; Ohtsuka, Satoshi; Matsuda, Yasushi

    2006-07-01

    In a feasibility study of ODS steel cladding, its high temperature oxidation resistance was evaluated. Although addition of Cr is effective for preventing high temperature oxidation, excessively higher amount of Cr leads to embrittlement due to the Cr-rich α' precipitate formation. In the ODS steel developed by the Japan Atomic Energy Agency (JAEA), the Cr content is controlled in 9Cr-ODS martensite and 12Cr-ODS ferrite. In this study, high temperature oxidation test was conducted for ODS steels, and their results were compared with that of conventional austenitic stainless steel and ferritic-martensitic stainless steel. Following results were obtained in this study. (1) 9Cr-ODS martensitic and 12Cr-ODS ferritic steel have superior high temperature oxidation resistance compared to 11mass%Cr PNC-FMS and even 17mass% SUS430 and equivalent to austenitic PNC316. (2) The superior oxidation resistance of ODS steel was attributed to earlier formation of the protective alpha-Cr 2 O 3 layer at the matrix and inner oxide scale interface. The grain size of ODS steel is finer than that of PNC-FMS, so the superior oxidation resistance of ODS steel can be attributed to the enhanced Cr-supplying rate throughout the accelerated grain boundary diffusion. Finely dispersed Y 2 O 3 oxide particles in the ODS steel matrix may also stabilized the adherence between the protective alpha-Cr 2 O 3 layer and the matrix. (author)

  4. Fracture behavior of the ODS steels prepared by internal oxidation

    Czech Academy of Sciences Publication Activity Database

    Stratil, Luděk; Šiška, Filip; Hadraba, Hynek; Bártková, Denisa; Fintová, Stanislava; Puchý, V.

    2017-01-01

    Roč. 124, NOV (2017), s. 1108-1111 ISSN 0920-3796 R&D Projects: GA ČR GJ15-21292Y; GA ČR(CZ) GA14-25246S Institutional support: RVO:68081723 Keywords : ODS * Internal oxidation * Fracture toughness * J-R curve * Fracture analysis Subject RIV: JG - Metallurgy OBOR OECD: Materials engineering Impact factor: 1.319, year: 2016

  5. Strangeness photoproduction at the BGO-OD experiment

    Energy Technology Data Exchange (ETDEWEB)

    Jude, Thomas [Physikalisches Institut, Bonn University (Germany); Collaboration: BGO-OD-Collaboration

    2016-07-01

    The BGO-OD experiment at the ELSA accelerator facility uses an energy tagged bremstrahlung photon beam to investigate the internal structure of the nucleon. The setup consists of a highly segmented BGO calorimeter surrounding the target, with a particle tracking magnetic spectrometer at forward angles. Compared to constituent quark models (CQMs), models including psuedoscalar meson-baryon interactions have had improved success in describing baryon excitation spectra. For example, the Λ(1405) appears to be dynamically generated from meson-baryon interactions at least to some extent. Vector-meson baryon interactions have also been predicted to dynamically generate states, which may have been observed in photoproduction reactions. BGO-OD is ideal for investigating low momentum transfer processes due to the acceptance and high momentum resolution at forward angles. This enables the investigation of degrees of freedom not derived from CQMs, and in particular, strangeness photoproduction where t-channel exchange mechanisms play a dominant role. With the first major data taking periods for BGO-OD complete, an extensive programme for the investigation of associated strangeness photoproduction has begun.

  6. Evaluation of Ion Irradiation Behavior of ODS Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Jin Sung; Kim, Min Chul; Hong, Jun Hwa; Han, Chang Hee; Chang, Young Mun; Bae, Chang Soo; Bae, Yoon Young; Chang, Moon Hee

    2006-08-15

    FM steel (Grade 92) and ODS alloy(MA956) specimens were ion irradiated with 122 MeV Ne ions. Irradiation temperatures were about 450 and 550 .deg. C and the peak dose was 1, 5, and 10 dpa. Cross-sectional TEM samples were prepared by the electrolytic Ni-plating after pre-treatment of the irradiated specimens. Irradiation cavities in FM steel and ODS alloy specimens were not much different in size; about 20 nm in diameter in both specimens irradiated at around 450 .deg. C. However, the size distribution of cavities in FM steel specimens was broader than that in ODS alloy specimen, indicating that the cavity growth probably via coalescence). It was noticeable that the location and the preferential growth of the cavities in FM steel specimens: cavities on the PAGB (prior austenite grain boundary) was significantly larger than those within the grains. This could be an important issue for the mechanical properties, especially high temperature creep, fracture toughness, and so on. The dependency of the dose threshold and swelling on the ratio of the inert gas concentration/dpa was analysed for the various irradiation source, including He, Ne, Fe/He, and fast neutron, and the empirical correlation was established.

  7. Cerium Titanate Nano dispersoids in Ni-base ODS Alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Suk Hoon; Chun, Young-Bum; Rhee, Chang-Kyu; Jang, Jinsung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Chung, Hee-Suk [Korea Basic Science Institute, Jeonju (Korea, Republic of)

    2016-10-15

    Oxide-dispersion-strengthened (ODS) nickel-base alloys have potential for use in rather demanding elevated-temperature environments, such as aircraft turbine engines, heat exchanger of nuclear reactor. For improved high temperature performance, several ODS alloys were developed which possess good elevated temperature strength and over-temperature capacity plus excellent static oxidation resistance. The high temperature strength of ODS alloys is due to the presence of a uniform dispersion of fine, inert particles. Ceria mixed oxides have been studied because of their application potential in the formation of nanoclusters. By first principle study, it was estimated that the formation energy of the Ce-O dimer with voids in the nickel base alloy is lower than other candidates. The result suggests that the dispersion of the Ceria mixed oxides can suppress the voiding or swelling behavior of nickel base alloy during neutron irradiation. In this study, the evolution of cerium titanate nano particles was investigated using in-situ TEM. It was found that the Ce{sub 2}Ti{sub 3}O{sub 9} phase was easily formed rather than remain as CeO{sub 2} during annealing; Ti was effective to form the finer oxide particles. Ce{sub 2}Ti{sub 3}O{sub 9} is expected to do the great roll as dispersoids in Ni-base alloy, contribute to achieve the better high temperature property, high swelling resistance during neutron radiation.

  8. Evaluation of Ion Irradiation Behavior of ODS Alloys

    International Nuclear Information System (INIS)

    Jang, Jin Sung; Kim, Min Chul; Hong, Jun Hwa; Han, Chang Hee; Chang, Young Mun; Bae, Chang Soo; Bae, Yoon Young; Chang, Moon Hee

    2006-08-01

    FM steel (Grade 92) and ODS alloy(MA956) specimens were ion irradiated with 122 MeV Ne ions. Irradiation temperatures were about 450 and 550 .deg. C and the peak dose was 1, 5, and 10 dpa. Cross-sectional TEM samples were prepared by the electrolytic Ni-plating after pre-treatment of the irradiated specimens. Irradiation cavities in FM steel and ODS alloy specimens were not much different in size; about 20 nm in diameter in both specimens irradiated at around 450 .deg. C. However, the size distribution of cavities in FM steel specimens was broader than that in ODS alloy specimen, indicating that the cavity growth probably via coalescence). It was noticeable that the location and the preferential growth of the cavities in FM steel specimens: cavities on the PAGB (prior austenite grain boundary) was significantly larger than those within the grains. This could be an important issue for the mechanical properties, especially high temperature creep, fracture toughness, and so on. The dependency of the dose threshold and swelling on the ratio of the inert gas concentration/dpa was analysed for the various irradiation source, including He, Ne, Fe/He, and fast neutron, and the empirical correlation was established

  9. Precipitate microstructure evolution in exposed IN738LC superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Strunz, Pavel, E-mail: strunz@ujf.cas.cz [Nuclear Physics Institute ASCR, CZ-25068 Řež near Prague (Czech Republic); Petrenec, Martin [Institute of Physics of Materials of the AS CR, Brno (Czech Republic); Gasser, Urs [Laboratory for Neutron Scattering, PSI, CH-5232 Villigen (Switzerland); Tobiáš, Jiří; Polák, Jaroslav [Institute of Physics of Materials of the AS CR, Brno (Czech Republic); Šaroun, Jan [Nuclear Physics Institute ASCR, CZ-25068 Řež near Prague (Czech Republic)

    2014-03-15

    Highlights: • Evolution of γ′-phase morphology in IN738LC Ni-base superalloy was examined by SANS. • In situ tests at high temperatures revealed trimodal precipitate distribution. • Formation, dissolution and (slow) kinetics of small γ′ precipitates was determined. • Equilibrium volume fraction of γ′ phase is significantly higher than 45%. • The small γ′ precipitates arise regardless the application of the mechanical load. -- Abstract: Nickel base superalloy IN738LC has been studied after low-cycle fatigue by Small Angle Neutron Scattering (SANS). Samples subjected to high-temperature low-cycle fatigue were annealed at various temperatures to change the size and the distribution of precipitates. Ex and in situ SANS and TEM studies were performed. It was found that additional precipitates are formed either during slow cooling from high temperatures or after reheating above 570 °C. Their size and distribution were evaluated. The precipitates arise regardless the application of the mechanical load. Nevertheless, these small precipitates influence low-cycle fatigue resistance. From the SANS data, it can be also deduced that the equilibrium volume fraction of γ′-precipitates at temperatures from room temperature to 825 °C is significantly higher than 45%. The kinetics of formation of small and medium-size γ′ precipitates at 700 and 800 °C was determined as well.

  10. Effects of cobalt in nickel-base superalloys

    Science.gov (United States)

    Tien, J. K.; Jarrett, R. N.

    1983-01-01

    The role of cobalt in a representative wrought nickel-base superalloy was determined. The results show cobalt affecting the solubility of elements in the gamma matrix, resulting in enhanced gamma' volume fraction, in the stabilization of MC-type carbides, and in the stabilization of sigma phase. In the particular alloy studied, these microstructural and microchemistry changes are insufficient in extent to impact on tensile strength, yield strength, and in the ductilities. Depending on the heat treatment, creep and stress rupture resistance can be cobalt sensitive. In the coarse grain, fully solutioned and aged condition, all of the alloy's 17% cobalt can be replaced by nickel without deleteriously affecting this resistance. In the fine grain, partially solutioned and aged condition, this resistance is deleteriously affected only when one-half or more of the initial cobalt content is removed. The structure and property results are discussed with respect to existing theories and with respect to other recent and earlier findings on the impact of cobalt, if any, on the performance of nickel-base superalloys.

  11. Failure mechanisms of superhard materials when cutting superalloys

    International Nuclear Information System (INIS)

    Focke, A.E.; Westermann, F.E.; Ermi, A.; Yavelak, J.; Hoch, M.

    1975-01-01

    The present research studies the reasons for the failure of tungsten carbide tools while cutting superalloys. There is a continuous layer of the superalloy in the bottom of the crater which from time to time is torn away locally, taking tungsten carbide crystal with it. Under recommended cutting conditions a plateau (unworn cutting surface) separates the crater from the cutting edge of the tool when cutting AISI 4340. This plateau is totally absent in all cutting of Inconel 718, even in short, two-minute tests. The crater intersects the cutting edge--only a thin wedge of carbide is left which either breaks off or deforms and wears very rapidly. Temperature measurements carried out by use of an infrared detector aimed on the corner of the tungsten carbide indicate at recommended speeds a sharp rise of the temperature at the beginning of the cutting operation, then a steady-state very slow increase as the cutting continues, and finally just before tool failure a very rapid increase in the temperature again. Scanning and replica electron microscopy through the crater and flank face shows that both under the crater and in the back of the cutting edge a fairly deep layer of ''disturbed metal'' exists in which the tungsten carbide grains are much smaller and have much more rounded edges than in the original material. 10 figures, 4 tables

  12. Microstrain evolution during creep of a high volume fraction superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Ma, S. [Materials Department, New Mexico Tech, Socorro, NM 87801 (United States); Brown, D. [Los Alamos National Laboratory, Los Alamos, NM (United States); Bourke, M.A.M. [Los Alamos National Laboratory, Los Alamos, NM (United States); Daymond, M.R. [Rutherford Appleton Laboratory, ISIS Facility, Chilton, Didcot, Oxon OX11 0QX (United Kingdom); Majumdar, B.S. [Materials Department, New Mexico Tech, Socorro, NM 87801 (United States)]. E-mail: majumdar@nmt.edu

    2005-06-15

    The creep of superalloys containing a high volume fraction of {gamma}' phase is significantly influenced by initial misfit and by the evolution of internal stresses. An in situ neutron diffraction technique was used to monitor elastic microstrains in a polycrystalline superalloy, CM247 LC. The misfit was nearly zero at room temperature and it increased to -0.17% at 900 deg. C. These values are rationalized in terms of thermal mismatch using an eigenstrain formulation and a simple formula is derived to relate the thermal mismatch to the misfit strain. During creep at 425 MPa at 900 deg. C, the material exhibited primarily tertiary behavior. For grains with [0 0 1] axis close to the loading direction, the elastic microstrain in the loading direction increased with creep time for the {gamma}' phase, whereas the opposite occurred for the {gamma} phase. These results are explained in terms of constrained deformation in the narrow {gamma} channels and by an interface dislocation buildup. TEM analysis of the crept microstructure provides evidence of the interface dislocation network.

  13. Creep properties of heat-resistant superalloys for nuclear plants in helium

    International Nuclear Information System (INIS)

    Shimizu, Shigeki; Satoh, Keisuke; Honda, Yoshio; Matsuda, Shozo; Murase, Hirokazu

    1979-01-01

    Creep properties of candidate superalloys for VHTR components in a helium environment at both temperatures of 800 0 C and 900 0 C were compared with those of the same alloys in the atmospheric condition, and the superalloys were contrasted with each other from the viewpoint of high temperature structural design. At 800 0 C, no significant effect of a helium environment on creep properties of the superalloys is observed. At 900 0 C, however, creep strength of Inconel 617, Incoloy 800 and Incoloy 807 in the helium environment decrease more than in the atmospheric environment. In Hastelloy X and Inconel 625, there is no significant difference between creep strengths in helium and those in the atmospheric condition. Concerning So and St values in helium at 900 0 C, Inconel 617 and Hastelloy X are clearly superior to other superalloys. (author)

  14. Advanced Scale Bridging Microstructure Analysis of Single Crystal Ni-Base Superalloys

    Czech Academy of Sciences Publication Activity Database

    Parsa, A. B.; Wollgramm, P.; Buck, H.; Somsen, C.; Kostka, A.; Povstugar, I.; Choi, P.-P.; Raabe, D.; Dlouhý, Antonín; Müller, J.; Spiecker, E.; Demtroder, K.; Schreuer, J.; Neuking, K.; Eggeler, G.

    2015-01-01

    Roč. 17, č. 2 (2015), s. 216-230 ISSN 1438-1656 Institutional support: RVO:68081723 Keywords : High temperature materials * Nickel based superalloys * EPMA * HRTEM Subject RIV: JG - Metallurgy Impact factor: 1.817, year: 2015

  15. High Temperature Degradation of Powder-processed Ni-based Superalloy

    Czech Academy of Sciences Publication Activity Database

    Luptáková, Natália; Pizúrová, Naděžda; Roupcová, Pavla; Dymáček, Petr

    2015-01-01

    Roč. 22, č. 2 (2015), s. 85-94 ISSN 1335-0803 Institutional support: RVO:68081723 Keywords : powder materials * polycrystalline Ni-based superalloy * creep machine grips * oxidation Subject RIV: JG - Metallurgy

  16. High temperature properties of polycrystalline γ"'-strengthened cobalt-base superalloys

    International Nuclear Information System (INIS)

    Bauer, Alexander

    2016-01-01

    The recent discovery of a stable γ"'-phase in Co-based superalloys opened up a pathway for the development of a new high temperature material class, which is similar in microstructure and properties to the modern γ"'-hardened Ni-based superalloys. In this work, the first attempt was done to check the influence of several for Ni-based superalloys typical alloying elements on the properties of the new Co-based superalloys. It became clear that the basic characteristics of the first experimental alloys are similar to those of the γ"'-hardened Ni-based alloys. The results of the multinary experimental alloys show that, based on the insight gained so far, targeted alloy development is possible. These materials have the potential to be used as disc materials in turbines.

  17. Nickel-base superalloy powder metallurgy: state-of-the-art

    International Nuclear Information System (INIS)

    Allen, M.M.; Athey, R.L.; Moore, J.B.

    1975-01-01

    Development of powder metallurgical methods for fabrication of Ni-base superalloy turbine engine disks is reviewed. Background studies are summarized and current state-of-art is discussed for the F100 jet engine, advanced applications, and forging processes

  18. Recovery of creep properties of the nickel-base superalloy nimonic 105

    CSIR Research Space (South Africa)

    Girdwood, RB

    1996-01-01

    Full Text Available Uniaxial constant stress creep tests were performed on the wrought nickel-base superalloy Nimonic 105. Entire creep curves were recorded and curve shapes analysed using the Theta Projection Concept. Rejuventive procedures were applied to pre...

  19. Microstructural studies of carbides in MAR-M247 nickel-based superalloy

    Science.gov (United States)

    Szczotok, A.; Rodak, K.

    2012-05-01

    Carbides play an important role in the strengthening of microstructures of nickel-based superalloys. Grain boundary carbides prevent or retard grain-boundary sliding and make the grain boundary stronger. Carbides can also tie up certain elements that would otherwise promote phase instability during service. Various types of carbides are possible in the microstructure of nickel-based superalloys, depending on the superalloy composition and processing. In this paper, scanning electron and scanning transmission electron microscopy studies of carbides occurring in the microstructure of polycrystalline MAR-M247 nickel-based superalloy were carried out. In the present work, MC and M23C6 carbides in the MAR-M247 microstructure were examined.

  20. Ice sheet in peril

    DEFF Research Database (Denmark)

    Hvidberg, Christine Schøtt

    2016-01-01

    Earth's large ice sheets in Greenland and Antarctica are major contributors to sea level change. At present, the Greenland Ice Sheet (see the photo) is losing mass in response to climate warming in Greenland (1), but the present changes also include a long-term response to past climate transitions...

  1. Mobility Balance Sheet 2009

    International Nuclear Information System (INIS)

    Jorritsma, P.; Derriks, H.; Francke, J.; Gordijn, H.; Groot, W.; Harms, L.; Van der Loop, H.; Peer, S.; Savelberg, F.; Wouters, P.

    2009-06-01

    The Mobility Balance Sheet provides an overview of the state of the art of mobility in the Netherlands. In addition to describing the development of mobility this report also provides explanations for the growth of passenger and freight transport. Moreover, the Mobility Balance Sheet also focuses on a topical theme: the effects of economic crises on mobility. [nl

  2. Structural Component Fabrication and Characterization of Advanced Radiation Resistant ODS Steel for Next Generation Nuclear Systems

    International Nuclear Information System (INIS)

    Noh, Sang Hoon; Kim, Young Chun; Jin, Hyun Ju; Choi, Byoung Kwon; Kang, Suk Hoon; Kim, Tae Kyu

    2016-01-01

    In a sodium-cooled fast reactor (SFR), the coolant outlet temperature and peak temperature of the fuel cladding tube will be about 545 .deg. C and 700 .deg. C with 250 dpa of a very high neutron dose rate. To realize this system, it is necessary to develop an advanced structural material having high creep and irradiation resistance at high temperatures. Austenitic stainless steel may be one of the candidates because of good strength and corrosion resistance at the high temperatures, however irradiation swelling severely occurred to 120dpa at high temperatures and this eventually leads to a decrease of the mechanical properties and dimensional stability. Advanced radiation resistant ODS steel (ARROS) has been newly developed for the in-core structural components in SFR, which has very attractive microstructures to achieve both superior creep and radiation resistances at high temperatures [4]. Nevertheless, the use of ARROS as a structural material essentially requires the fabrication technology development for component parts such as sheet, plate and tube. In this study, plates and tubes were tentatively fabricated with a newly developed alloy, ARROS. Microstructures as well as mechanical properties were also investigated to determine the optimized condition of the fabrication processes.

  3. Analysis of Effective and Internal Cyclic Stress Components in the Inconel Superalloy Fatigued at Elevated Temperature

    Czech Academy of Sciences Publication Activity Database

    Šmíd, Miroslav; Petrenec, Martin; Polák, Jaroslav; Obrtlík, Karel; Chlupová, Alice

    2011-01-01

    Roč. 278, 4 July (2011), s. 393-398 ISSN 1022-6680. [European Symposium on Superalloys and their Application. Wildbad Kreuth, 25.5.2010-28.5.2010] R&D Projects: GA ČR GA106/08/1631 Institutional research plan: CEZ:AV0Z20410507 Keywords : low cycle fatigue * superalloys * high temperature * hysteresis loop * effective and internal stresses Subject RIV: JL - Materials Fatigue, Friction Mechanics; JL - Materials Fatigue, Friction Mechanics (UFM-A)

  4. Design of high entropy alloys based on the experience from commercial superalloys

    Science.gov (United States)

    Wang, Z.; Huang, Y.; Wang, J.; Liu, C. T.

    2015-01-01

    High entropy alloys (HEAs) have been drawing increasing attention recently and gratifying results have been obtained. However, the existing metallurgic rules of HEAs could not provide specific information of selecting candidate alloys for structural applications. Our brief survey reveals that many commercial superalloys have medium and even to high configurational entropies. The experience of commercial superalloys provides a clue for helping us in the development of HEAs for structural applications.

  5. Effects of cutting parameters on machinability characteristics of Ni-based superalloys: a review

    Directory of Open Access Journals (Sweden)

    Kaya Eren

    2017-12-01

    Full Text Available Nickel based superalloys offer high strength, corrosion resistance, thermal stability and superb thermal fatigue properties. However, they have been one of the most difficult materials to machine due to these properties. Although we are witnessing improved machining strategies with the developing machining, tooling and inspection technologies, machining of nickel based superalloys is still a challenging task due to in-process strains and post process part quality demands.

  6. Predicting the morphologies of {\\gamma}' precipitates in cobalt-based superalloys

    OpenAIRE

    Jokisaari, Andrea M.; Naghavi, Shahab S.; Wolverton, Chris; Voorhees, Peter W.; Heinonen, Olle G.

    2017-01-01

    Cobalt-based alloys with {\\gamma}/{\\gamma}' microstructures have the potential to become the next generation of superalloys, but alloy compositions and processing steps must be optimized to improve coarsening, creep, and rafting behavior. While these behaviors are different than in nickel-based superalloys, alloy development can be accelerated by understanding the thermodynamic factors influencing microstructure evolution. In this work, we develop a phase field model informed by first-princip...

  7. Welding and Weldability of Directionally Solidified Single Crystal Nickel-Base Superalloys

    Energy Technology Data Exchange (ETDEWEB)

    Vitek, J M; David, S A; Reed, R W; Burke, M A; Fitzgerald, T J

    1997-09-01

    Nickel-base superalloys are used extensively in high-temperature service applications, and in particular, in components of turbine engines. To improve high-temperature creep properties, these alloys are often used in the directionally-solidified or single-crystal form. The objective of this CRADA project was to investigate the weldability of both experimental and commercial nickel-base superalloys in polycrystalline, directionally-solidified, and single-crystal forms.

  8. The Effect of Forging Variables on the Supersolvus Heat-Treatment Response of Powder-Metallurgy Nickel-Base Superalloys

    Science.gov (United States)

    2014-12-01

    AFRL-RX-WP-JA-2015-0160 THE EFFECT OF FORGING VARIABLES ON THE SUPERSOLVUS HEAT-TREATMENT RESPONSE OF POWDER - METALLURGY NICKEL-BASE SUPERALLOYS... POWDER - METALLURGY NICKEL- BASE SUPERALLOYS (POSTPRINT) 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62102F 6. AUTHOR...treatment (SSHT) of two powder - metallurgy , gamma–gamma prime superalloys, IN-100 and LSHR, was established. For this purpose, isothermal, hot

  9. Effect of zirconium addition on the microstructure and mechanical properties of ODS ferritic steels containing aluminum

    International Nuclear Information System (INIS)

    Gao, R.; Zhang, T.; Wang, X.P.; Fang, Q.F.; Liu, C.S.

    2014-01-01

    The oxide dispersion strengthened (ODS) ferritic steels with nominal composition of Fe–16Cr–2W–0.5Ti–0.4Y 2 O 3 –4Al–1Zr (16Cr–4Al–Zr–ODS) were fabricated by a sol–gel method combining with mechanical alloying and spark plasma sintering (SPS) technique, and the 16Cr–ODS and 16Cr–4Al–ODS steels were prepared for comparison in the same way. Microstructure characterization reveals that in the 16Cr–4Al–ODS steel coarse Y–Al–O particles were formed while in the 16Cr–4Al–Zr–ODS steel finer Y–Zr–O particles were formed. The mean size and number density of the nano-oxide particles in the 16Cr–4Al–Zr–ODS steel are about 25 nm and 2.6 × 10 21 /m 3 , respectively. The ultimate tensile strength (UTS) of the 16Cr–ODS steel is about 1045 MPa, but UTS of the 16Cr–4Al–ODS steel decreases to 974 MPa. However, UTS of the 16Cr–4Al–Zr–ODS steel increases to 1180 MPa while keeping a large uniform elongation up to 23%, indicating the enhancement of mechanical properties by Zr addition

  10. Carbon sheet pumping

    International Nuclear Information System (INIS)

    Ohyabu, N.; Sagara, A.; Kawamura, T.; Motojima, O.; Ono, T.

    1993-07-01

    A new hydrogen pumping scheme has been proposed which controls recycling of the particles for significant improvement of the energy confinement in toroidal magnetic fusion devices. In this scheme, a part of the vacuum vessel surface near the divertor is covered with carbon sheets of a large surface area. Before discharge initiation, the sheets are baked up to 700 ∼ 1000degC to remove the previously trapped hydrogen atoms. After being cooled down to below ∼ 200degC, the unsaturated carbon sheets trap high energy charge exchange hydrogen atoms effectively during a discharge and overall pumping efficiency can be as high as ∼ 50 %. (author)

  11. Microstructural characterization of ODS ferritic steels at different processing stages

    Energy Technology Data Exchange (ETDEWEB)

    Gil, E., E-mail: egil@ceit.es; Ordás, N.; García-Rosales, C.; Iturriza, I., E-mail: iiturriza@ceit.es

    2015-10-15

    Highlights: • ODS ferritic stainless steel produced by new route without mechanical alloying. • Fully dense ferritic stainless steels containing Y and Ti were obtained by HIPping. • Y and Ti-rich precipitates prevent grain growth during heat treatment up to 1320 °C. • HIPping at 1220 °C dissolves the metastable oxides on PPBs. - Abstract: Nanostructured Oxide Dispersion Strengthened Reduced Activation Ferritic Stainless Steels (ODS RAF) are promising structural materials for fusion reactors, due to their ultrafine microstructure and the presence of a dispersion of Y–Ti–O nanoclusters that provide excellent creep strength at high temperatures (up to 750 °C). The traditional powder metallurgical route to produce these steels is based on Gas Atomization (GA) + Mechanical Alloying (MA) + HIP + ThermoMechanical Treatments (TMTs). Recently, alternative methods have arisen to avoid the MA step. In line with this new approach, ferritic stainless steel powders were produced by gas atomization and HIPped, after adjusting their oxygen, Y and Ti contents to form Y–Ti–O nanoclusters during subsequent heat treatments. The microstructure of as-HIPped steels mainly consists of ferrite grains, Y–Ti precipitates, carbides and oxides on Prior Particle Boundaries (PPBs). Post-HIP heat treatments performed at high temperatures (1270 and 1300 °C) evaluated the feasibility of achieving a complete dissolution of the oxides on PPBs and a precipitation of ultrafine Ti- and Y-rich oxides in the Fe14Cr2W matrix. FEG-SEM with extensive EDS analysis was used to characterize the microstructure of the atomized powders and the ODS-RAF specimens after HIP consolidation and post-HIP heat treatments. A deeper characterization of atomized powder was carried out by TEM.

  12. The laser beam welding test of ODS fuel claddings

    International Nuclear Information System (INIS)

    Uwaba, Tomoyuki; Ukai, Shigeharu

    2004-06-01

    As a alternative method of pressurized resistance welding being currently developed, integrity evaluations for a laser beam welding joint between a ODS cladding tube and a FMS end plug were conducted for the purpose of studying the applicability of the laser beam welding technique to the welding with the lower end plug. The laser beam welding causes blowholes in the welding zone, whose effect on the high cycle fatigue strength of the joint is essential because of the flow-induced vibration during irradiation. The rotary bending tests using specimens with laser beam welding between ODS cladding tubes and FMS end plugs were carried out to evaluate the fatigue strength of the welding joint containing blowholes. The fatigue limit of stress amplitude about 200 MPa from 10 6 -10 7 cycles suggested that the laser beam welding joint had enough strength against the flow-induced vibration. Sizing of blowholes in the welding zone by using a micro X ray CT technique estimated the rate of defect areas due to blowholes at 1-2%. It is likely that the fatigue strength remained nearly unaffected by blowholes because of the no correlation between the breach of the rotary bending test specimen and the rate of defect area. Based on results of tensile test, internal burst test, Charpy impact test and fatigue test of welded zone, including study of allowable criteria of blowholes in the inspection, it is concluded that the laser beam welding can be probably applied to the welding between the ODS cladding tube and the FMS lower end plug. (author)

  13. Precipitates and boundaries interaction in ferritic ODS steels

    Energy Technology Data Exchange (ETDEWEB)

    Sallez, Nicolas, E-mail: nicolas.sallez@simap.grenoble-inp.fr [Univ. Grenoble Alpes, SIMAP, F-38000 Grenoble (France); Hatzoglou, Constantinos [Groupe de Physique des Matériaux, Université et INSA de Rouen, UMR CNRS 6634, Normandie Université (France); Delabrouille, Fredéric [EDF–EDF R& D, Les Renardières, 77818 Moret-sur-Loing (France); Sornin, Denis; Chaffron, Laurent [CEA, DEN, Service de Recherches Métallurgiques Appliqué, 91191 Gif-sur-Yvette (France); Blat-Yrieix, Martine [EDF–EDF R& D, Les Renardières, 77818 Moret-sur-Loing (France); Radiguet, Bertrand; Pareige, Philippe [Groupe de Physique des Matériaux, Université et INSA de Rouen, UMR CNRS 6634, Normandie Université (France); Donnadieu, Patricia; Bréchet, Yves [Univ. Grenoble Alpes, SIMAP, F-38000 Grenoble (France)

    2016-04-15

    In the course of a recrystallization study of Oxide Dispersion Strengthened (ODS) ferritic steels during extrusion, particular interest was paid to the (GB) Grain Boundaries interaction with precipitates. Complementary and corresponding characterization experiments using Transmission Electron Microscopy (TEM), Energy Dispersive X-ray spectroscopy (EDX) and Atom Probe Tomography (APT) have been carried out on a voluntarily interrupted extrusion or extruded samples. Microscopic observations of Precipitate Free Zones (PFZ) and precipitates alignments suggest precipitate interaction with migrating GB involving dissolution and Oswald ripening of the precipitates. This is consistent with the local chemical information gathered by EDX and APT. This original mechanism for ODS steels is similar to what had been proposed in the late 80s for similar observation made on Ti alloys reinforced by nanosized yttrium oxides: An interaction mechanism between grain boundaries and precipitates involving a diffusion controlled process of precipitates dissolution at grain boundaries. It is believed that this mechanism can be of primary importance to explain the mechanical behaviour of such steels. - Highlights: • To study the microstructural evolution of a ferritic ODS steel during its extrusion, observations have been carried on samples resulting from a voluntarily interrupted extrusion and extruded materials. • A highly heterogeneous precipitate population have been observed. Nanosized coherent precipitates (2–5 nm) on both sides of the grain boundaries despite grain boundary migration after precipitation due to further thermo-mechanical processing as well as coarse precipitates (10–40 nm) alignments are observed on the grain boundaries and within the grains, parallel to the grain boundaries. • Asymmetrical PFZs can be observed around precipitates alignments and grain boundaries. Using TEM with EDX and APT we have been able to ensure that the PFZs are chemically depleted.

  14. Investigation of the Mechanical Properties and Microstructure of Nickel Superalloys Processed in Shear Forming / Identyfikacja Właściwości Mechanicznych Oraz Mikrostruktury Superstopów Niklu Przetwarzanych W Procesie Kształtowania Obrotowego

    Directory of Open Access Journals (Sweden)

    Żaba K.

    2015-12-01

    Full Text Available The paper presents the research results of the mechanical properties and microstructure of the material in initial state and parts made from nickel superalloy Inconel®718 in the rotary forming process with laser heating. In the first step was carried out basic research of chemical composition, mechanical properties, hardness and microstructure of sheet in initial state. Then from the metal sheet, in industrial conditions, was made axisymmetric parts in the flow and shear forming with laser heating. Parts were subjected to detailed studies focused on the analysis of changes in the mechanical properties and microstructure in the relation to the material in initial state. The analysis was based on the tests results of strength and plastic properties, hardness, microstructural observations and X-ray microanalysis in the areas where defects appear and beyond. The results are presented in the form of tables, charts, and photographs of the microstructure.

  15. Linearly polarised photons at the BGO-OD experiment

    Energy Technology Data Exchange (ETDEWEB)

    Bella, Andreas [Physikalisches Institut, Universitaet Bonn (Germany)

    2016-07-01

    The BGO-OD experiment, located at the ELSA accelerator of the University of Bonn studies photoproduction reactions off the nucleon. A real, energy-tagged photon beam is produced via bremsstrahlung by exposing a thin radiator to the electron beam provided by ELSA. Linear polarisation is obtained by coherent bremsstrahlung. To do this we use a 570 μm thick diamond radiator. The degree of polarisation is obtained from the bremsstrahlung spectrum. A consistency check is performed by extracting the already well measured beam asymmetry Σ in π{sup 0} photoproduction off the proton.

  16. Linearly polarised photons at the BGO-OD experiment

    Energy Technology Data Exchange (ETDEWEB)

    Bella, Andreas [Physikalisches Institut, Universitaet Bonn (Germany); Collaboration: BGO-OD-Collaboration

    2015-07-01

    The BGO-OD experiment, located at the ELSA accelerator of the University of Bonn, aims at the study of photoproduction reactions off the nucleon. A real, energy-tagged photon beam is produced via bremsstrahlung by irradiating a thin radiator with the electron beam provided by ELSA. Linear polarisation is obtained by coherent bremsstrahlung. This requires a crystal radiator; in our case a 570 μm thick diamond is used. The production mechanism of a linearly polarised photon beam via coherent bremsstrahlung, the determination of the degree of polarisation and first results obtained with a linearly polarised photon beam are shown in this talk.

  17. Void formation in ODS EUROFER produced by hot isostatic pressing

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, Y.; Monge, M.A.; Munoz, A.; Leguey, T.; Pareja, R. [Madrid Univ. Carlos-3, Dept. de Fisica (Spain); Castro, V. de [Oxford Univ., Dept. of Materials (United Kingdom)

    2007-07-01

    Full text of publication follows: An obstacle in the development of oxide dispersion strengthened (ODS) steels for structural applications in fusion reactors is the toughness lack of the material produced by powder metallurgy and consolidated by hot isostatic pressing (HIP). In particular, ODS EUROFER steel with Y{sub 2}O{sub 3} particles appears to exhibit poor impact properties. To asses the capabilities of this material, it is necessary elucidate if its failure is an inherent characteristic of the production process that can not be mitigated by normalizing and tempering treatments. In order to investigate this particular point, the evolution of the structural defects retained in the ODS material during isochronal annealing has been probed by positron annihilation spectroscopy. The present study has been performed on bail milled EUROFER powders consolidated by HIP, containing 0.25 wt % Y{sub 2}O{sub 3} and without Y{sub 2}O{sub 3}. For comparison, un-milled EUROFER powder consolidated under identical conditions, and as-received EUROFER97 plate produced by Boehler AG have been also investigated. Samples from these four materials were isochronally annealed for 90 min up to 1323 K. Materials produced from milled powders had a longer positron lifetime than the one produced from un-milled powder or the EUROFER plate. In the material containing Y{sub 2}O{sub 3}, i.e. in ODS EUROFER, annealing above 723 K produced a continuous increase in the mean positron lifetime <{tau}> up to reach a maximum value of 208 ps after annealing at 1223 K. A similar annealing behavior was observed for Y{sub 2}O{sub 3}-free milled EUROFER (milled EUROFER), but the <{tau}> value steeply changed from {approx}160 ps at 823 K to {approx}200 ps after annealing at 1023 K. Subsequent anneals above this temperature produced meaningless changes in <{tau}>. The <{tau}> increase in milled EUROFER was accompanied by the intensity increase of a lifetime component of {approx}360 ps that is characteristic

  18. Optimising mechanical properties of hot forged nickel superalloy 625 components

    Science.gov (United States)

    Singo, Nthambe; Coles, John; Rosochowska, Malgorzata; Lalvani, Himanshu; Hernandez, Jose; Ion, William

    2018-05-01

    Hot forging and subsequent heat treatment were resulting in substandard mechanical properties of nickel superalloy, Alloy 625, components. The low strength was found to be due to inadequate deformation during forging, excessive grain growth and precipitation of carbides during subsequent heat treatment. Experimentation in a drop forging company and heat treatment facility led to the establishment of optimal parameters to minimise grain size and mitigate the adverse effects of carbide precipitation, leading to successful fulfilment of mechanical property specifications. This was achieved by reducing the number of operations, maximising the extent of deformation by changing the slug dimensions and its orientation in the die, and minimising the time of exposure to elevated temperatures in both the forging and subsequent heat treatment processes to avoid grain growth.

  19. Computer aided design of nickel-base superalloys

    International Nuclear Information System (INIS)

    Lawrence, P.J.

    1988-01-01

    This paper describes a computer aided design process for Ni-base superalloys developed and employed at ASEA Brown Boveri. The technique involves a series of modules each of which predicts a particular property of a hypothetical new composition. In the first stage of the development of this design techniques modules were produced to predict phase stability, using PHACOMP, and high temperature creep strength and hot corrosion resistance, using multiple linear regression equations derived from the data in the literature. Alloys designed using these technique are also discussed and, in particular, shortcomings of the design process are highlighted. This information was then used to produce a revamped design methodology involving extra modules, including prediction of an alloy's gamma-prime content. (orig.)

  20. N18, powder metallurgy superalloy for disks: Development and applications

    Energy Technology Data Exchange (ETDEWEB)

    Guedou, J.Y.; Lautridou, J.C.; Honnorat, Y. (SNECMA, Evry (France). Materials and Processes Dept.)

    1993-08-01

    The preliminary industrial development of a powder metallurgy (PM) superalloy, designated N18, for disk applications has been completed. This alloy exhibits good overall mechanical properties after appropriate processing of the material. These properties have been measured on both isothermally forged and extruded billets, as well as on specimens cut from actual parts. The temperature capability of the alloy is about 700 C for long-term applications and approximately 750 C for short-term use because of microstructural instability. Further improvements in creep and crack propagation properties, without significant reduction in tensile strength, are possible through appropriate thermomechanical processing, which results in a large controlled grain size. Spin pit tests on subscale disks have confirmed that the N18 alloy has a higher resistance than PM Astrology and is therefore an excellent alloy for modern turbine disk applications.

  1. STABILITY ANALYSIS OF RADIAL TURNING PROCESS FOR SUPERALLOYS

    Directory of Open Access Journals (Sweden)

    Alberto JIMÉNEZ

    2017-07-01

    Full Text Available Stability detection in machining processes is an essential component for the design of efficient machining processes. Automatic methods are able to determine when instability is happening and prevent possible machine failures. In this work a variety of methods are proposed for detecting stability anomalies based on the measured forces in the radial turning process of superalloys. Two different methods are proposed to determine instabilities. Each one is tested on real data obtained in the machining of Waspalloy, Haynes 282 and Inconel 718. Experimental data, in both Conventional and High Pressure Coolant (HPC environments, are set in four different states depending on materials grain size and Hard-ness (LGA, LGS, SGA and SGS. Results reveal that PCA method is useful for visualization of the process and detection of anomalies in online processes.

  2. Pressure dependence of hydrogen bonding in metal deuteroxides: a neutron powder diffraction study of Mn(OD)2 and β-Co(OD)2

    International Nuclear Information System (INIS)

    Parise, J.B.; Theroux, B.; Li, R.; Loveday, J.S.; Marshall, W.G.; Klotz, S.

    1998-01-01

    The structures of deuterated pyrochroite, Mn(OD) 2 and β-Co(OD) 2 have been refined using the Rietveld method and neutron powder diffraction data collected in an opposed-anvil high pressure (Paris-Edinburgh) cell from room pressure to 9 GPa. The equation of state for Mn(OD) 2 was determined (K=41(3) GPa for fixed K'=4.7) and found to be consistent with previous studies of the isostructural brucite, Mg(OD) 2 . The compressibility of β-Co(OD) 2 on the other hand is apparently anomalous. The c-axis initially decreases at 3 times the rate of decrease of the a-axis; the ratio decreases to about 1.5 at an estimated 6 GPa before increasing again beyond this pressure. There is no obvious corresponding anomaly in the details of the atomic structure. In both materials there is an increase in the D-site disorder with pressure. A split-site model for the D-positions best fits the data at pressures above 8 GPa. There is no statistically significant increase in the O-D interatomic distance at increased pressure while the hydrogen bonding interaction D..O appears to increase as this distance decreases and the O-D..O angle increases. The intramolecular O-D bond valences, determined indirectly from the intermolecular D..O distances, decrease steadily for both materials as pressure is increased. (orig.)

  3. Anesthesia Fact Sheet

    Science.gov (United States)

    ... Education About NIGMS NIGMS Home > Science Education > Anesthesia Anesthesia Tagline (Optional) Middle/Main Content Area En español ... Version (464 KB) Other Fact Sheets What is anesthesia? Anesthesia is a medical treatment that prevents patients ...

  4. Structural Biology Fact Sheet

    Science.gov (United States)

    ... NIGMS NIGMS Home > Science Education > Structural Biology Structural Biology Tagline (Optional) Middle/Main Content Area PDF Version (688 KB) Other Fact Sheets What is structural biology? Structural biology is the study of how biological ...

  5. Radiation protecting sheet

    International Nuclear Information System (INIS)

    Makiguchi, Hiroshi.

    1989-01-01

    As protection sheets used in radioactivity administration areas, a thermoplastic polyurethane composition sheet with a thickness of less 0.5 mm, solid content (ash) of less than 5% and a shore D hardness of less than 60 is used. A composite sheet with thickness of less than 0.5 mm laminated or coated with such a thermoplastic polyurethane composition as a surface layer and the thermoplastic polyurethane composition sheet applied with secondary fabrication are used. This can satisfy all of the required properties, such as draping property, abrasion resistance, high breaking strength, necking resistance, endurance strength, as well as chemical resistance and easy burnability in burning furnace. Further, by forming uneveness on the surface by means of embossing, etc. safety problems such as slippage during operation and walking can be overcome. (T.M.)

  6. Global ice sheet modeling

    International Nuclear Information System (INIS)

    Hughes, T.J.; Fastook, J.L.

    1994-05-01

    The University of Maine conducted this study for Pacific Northwest Laboratory (PNL) as part of a global climate modeling task for site characterization of the potential nuclear waste respository site at Yucca Mountain, NV. The purpose of the study was to develop a global ice sheet dynamics model that will forecast the three-dimensional configuration of global ice sheets for specific climate change scenarios. The objective of the third (final) year of the work was to produce ice sheet data for glaciation scenarios covering the next 100,000 years. This was accomplished using both the map-plane and flowband solutions of our time-dependent, finite-element gridpoint model. The theory and equations used to develop the ice sheet models are presented. Three future scenarios were simulated by the model and results are discussed

  7. Energy information sheets

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-07-01

    The National Energy Information Center (NEIC), as part of its mission, provides energy information and referral assistance to Federal, State, and local governments, the academic community, business and industrial organizations, and the public. The Energy Information Sheets was developed to provide general information on various aspects of fuel production, prices, consumption, and capability. Additional information on related subject matter can be found in other Energy Information Administration (EIA) publications as referenced at the end of each sheet.

  8. TEM characterization of simultaneous triple ion implanted ODS Fe12Cr

    International Nuclear Information System (INIS)

    Castro, Vanessa de; Briceno, Martha; Lozano-Perez, Sergio; Trocellier, Patrick; Roberts, Steve G.; Pareja, Ramiro

    2014-01-01

    Understanding the behavior of oxide dispersion strengthened (ODS) ferritic/martensitic steels under irradiation is vital in the design of advanced fusion reactors. In this work, a simultaneous triple ion implanted ODS Fe12Cr steel was investigated by transmission electron microscopy in order to determine the effect of irradiation on the grain and dislocation structures, oxide nanoparticles and other secondary phases present in the steel. The ODS steel was irradiated at RT with Fe 8+ , He + and H + at the JANNUS-Saclay facility to a damage of 4.4 dpa. Results show that ODS nanoparticles appear very stable under these irradiation conditions

  9. TEM characterization of simultaneous triple ion implanted ODS Fe12Cr

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Vanessa de, E-mail: vanessa.decastro@uc3m.es [Departamento de Física, Universidad Carlos III de Madrid, Avda. de la Universidad 30, 28911 Leganés, Madrid (Spain); Briceno, Martha [Department of Materials, University of Oxford, Oxford OX1 3PH (United Kingdom); Johnson Matthey Technology Centre, Blount’s Court Rd, Sonning Common RG4 9NH (United Kingdom); Lozano-Perez, Sergio [Department of Materials, University of Oxford, Oxford OX1 3PH (United Kingdom); Trocellier, Patrick [CEA, DEN, Service de Recherches de Métallurgie Physique, Laboratoire JANNUS, F-91191 Gif-sur-Yvette (France); Roberts, Steve G. [Department of Materials, University of Oxford, Oxford OX1 3PH (United Kingdom); Pareja, Ramiro [Departamento de Física, Universidad Carlos III de Madrid, Avda. de la Universidad 30, 28911 Leganés, Madrid (Spain)

    2014-12-15

    Understanding the behavior of oxide dispersion strengthened (ODS) ferritic/martensitic steels under irradiation is vital in the design of advanced fusion reactors. In this work, a simultaneous triple ion implanted ODS Fe12Cr steel was investigated by transmission electron microscopy in order to determine the effect of irradiation on the grain and dislocation structures, oxide nanoparticles and other secondary phases present in the steel. The ODS steel was irradiated at RT with Fe{sup 8+}, He{sup +} and H{sup +} at the JANNUS-Saclay facility to a damage of 4.4 dpa. Results show that ODS nanoparticles appear very stable under these irradiation conditions.

  10. Effects of Zr Addition on Strengthening Mechanisms of Al-Alloyed High-Cr ODS Steels.

    Science.gov (United States)

    Ren, Jian; Yu, Liming; Liu, Yongchang; Liu, Chenxi; Li, Huijun; Wu, Jiefeng

    2018-01-12

    Oxide dispersion strengthened (ODS) steels with different contents of zirconium (denoted as 16Cr ODS, 16Cr-0.3Zr ODS and 16Cr-0.6Zr ODS) were fabricated to investigate the effects of Zr on strengthening mechanism of Al-alloyed 16Cr ODS steel. Electron backscatter diffraction (EBSD) results show that the mean grain size of ODS steels could be decreased by Zr addition. Transmission electron microscope (TEM) results indicate that Zr addition could increase the number density but decrease the mean diameter and inter-particle spacing of oxide particles. Furthermore, it is also found that in addition to Y-Al-O nanoparticles, Y-Zr-O oxides with finer size were observed in 16Cr-0.3Zr ODS and 16Cr-0.6Zr ODS steels. These changes in microstructure significantly increase the yield strength (YS) and ultimate tensile strength (UTS) of ODS steels through mechanisms of grain boundary strengthening and dispersion strengthening.

  11. OD (order-disorder) character of the crystal structure of godlevskite Ni9S8

    DEFF Research Database (Denmark)

    Merlino, Stefano; Makovicky, Emil

    2009-01-01

    Godlevskite Ni9S8 has been found to be an OD (order-disorder) structure consisting of two kinds of OD layers in strict alternation; these layers display stacking disorder. They have layer symmetries P( )2m and P212(2), respectively (symmetry elements in parentheses are perpendicular to OD layers......). Two structures with maximum degree of order (MDO polytypes), with space-group symmetries A222 and I4122, respectively, exist, together with more complex polytypes or disordered sequences. The OD character is in keeping with the frequent twinning of godlevskite....

  12. Overview of welding of oxide dispersion strengthened (ODS) alloys for advanced nuclear reactor applications

    International Nuclear Information System (INIS)

    Kalvala, Prasad Rao; Raja, K.S.; Misra, Manoranjan; Tache, Ricard A.

    2009-01-01

    Oxide dispersion strengthened (ODS) alloys are very promising materials for Generation IV reactors with a potential to be used at elevated temperatures under severe neutron exposure environment. Welding of the ODS alloys is an understudied problem. In this paper, an overview of welding of the ODS alloys useful for advanced nuclear reactor applications is presented. The microstructural changes and the resultant mechanical properties obtained by various solid state welding processes are reviewed. Based on our results on PM2000, an approach for future work on welding of the ODS alloys is suggested. (author)

  13. Strangeness photoproduction at the BGO-OD experiment

    Energy Technology Data Exchange (ETDEWEB)

    Jude, Thomas [Physikalisches Institut, Universitaet Bonn, Nussallee 12, Bonn (Germany); Collaboration: BGO-OD-Collaboration

    2015-07-01

    The BGO-OD experiment at the ELSA accelerator facility uses an energy tagged bremstrahlung photon beam to investigate the internal structure of the nucleon. The setup consists of a highly segmented BGO calorimeter surrounding the target, with a particle tracking magnetic spectrometer at forward angles. The BGO-OD is ideal for investigating the photoproduction of hadrons of non-zero strangeness. The high momentum resolution at forward angles covers a kinematic region where t-channel exchange mechanisms play a dominant role. This is complemented by the neutral and charged particle identification in the BGO calorimeter for the identification of hyperon decays. The first part of an extensive physics programme includes measurements of the differential cross section at forward angles for γp → K{sup +}Λ and, using linearly polarised photons, the beam asymmetry, Σ, for γp → K{sup 0}Σ{sup +}. This latter measurement is focussed on the K* threshold region where a cusp-like structure was recently observed in the total cross section. Analysis of these reaction channels for both real and simulated data is presented.

  14. ODS steel fabrication: relationships between process, microstructure and mechanical properties

    International Nuclear Information System (INIS)

    Couvrat, M.

    2011-01-01

    Oxide Dispersion Strengthened (ODS) steels are promising candidate materials for generation IV and fusion nuclear energy systems thanks to their excellent thermal stability, high-temperature creep strength and good irradiation resistance. Their superior properties are attributed both to their nano-structured matrix and to a high density of Y-Ti-O nano-scale clusters (NCs). ODS steels are generally prepared by Mechanical Alloying of a pre-alloyed Fe-Cr-W-Ti powder with Y 2 O 3 powder. A fully dense bar or tube is then produced from this nano-structured powder by the mean of hot extrusion. The aim of this work was to determine the main parameters of the process of hot extrusion and to understand the link between the fabrication process, the microstructure and the mechanical properties. The material microstructure was characterized at each step of the process and bars were extruded with varying hot extrusion parameters so as to identify the impact of these parameters. Temperature then appeared to be the main parameter having a great impact on microstructure and mechanical properties of the extruded material. We then proposed a cartography giving the microstructure versus the process parameters. Based on these results, it is possible to control very accurately the obtained material microstructure and mechanical properties setting the extrusion parameters. (author) [fr

  15. Microstructure and mechanical behavior of ODS and non-ODS Fe–14Cr model alloys produced by spark plasma sintering

    International Nuclear Information System (INIS)

    Auger, M.A.; Castro, V. de; Leguey, T.; Muñoz, A.; Pareja, R.

    2013-01-01

    In this work the spark plasma sintering (SPS) technique has been explored as an alternative consolidation route for producing ultra-fine grained Fe–14Cr model alloys containing a dispersion of oxide nanoparticles. Elemental powders of Fe and Cr, and nanosized Y 2 O 3 powder have been mechanically alloyed in a planetary ball mill and rapidly sintered in a spark plasma furnace. Two alloys, with nominal compositions Fe–14%Cr and Fe–14%Cr–0.3%Y 2 O 3 (wt.%), have been fabricated and their microstructure and mechanical properties investigated. The results have been compared with those obtained for other powder metallurgy processed alloys of the same composition but consolidated by hot isostatic pressing. The SPS technique under the present conditions has produced Fe–14Cr materials that apparently exhibit different microstructures yielding inferior mechanical properties than the counterpart material consolidated by hot isostatic pressing. Although the presence of a dispersion of Y-rich particles is evident, the oxide dispersion strengthened (ODS) Fe–14Cr alloy consolidated by SPS exhibits poor tensile properties. The extensive decoration of the powder particle surfaces with Cr-rich precipitates and the residual porosity appear to be responsible for the impaired properties of this ODS alloy consolidated by SPS

  16. Microstructure and mechanical behavior of ODS and non-ODS Fe–14Cr model alloys produced by spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Auger, M.A.; Castro, V. de [Departamento de Física, Universidad Carlos III de Madrid, 28911 Leganés (Spain); Leguey, T., E-mail: leguey@fis.uc3m.es [Departamento de Física, Universidad Carlos III de Madrid, 28911 Leganés (Spain); Muñoz, A.; Pareja, R. [Departamento de Física, Universidad Carlos III de Madrid, 28911 Leganés (Spain)

    2013-05-15

    In this work the spark plasma sintering (SPS) technique has been explored as an alternative consolidation route for producing ultra-fine grained Fe–14Cr model alloys containing a dispersion of oxide nanoparticles. Elemental powders of Fe and Cr, and nanosized Y{sub 2}O{sub 3} powder have been mechanically alloyed in a planetary ball mill and rapidly sintered in a spark plasma furnace. Two alloys, with nominal compositions Fe–14%Cr and Fe–14%Cr–0.3%Y{sub 2}O{sub 3} (wt.%), have been fabricated and their microstructure and mechanical properties investigated. The results have been compared with those obtained for other powder metallurgy processed alloys of the same composition but consolidated by hot isostatic pressing. The SPS technique under the present conditions has produced Fe–14Cr materials that apparently exhibit different microstructures yielding inferior mechanical properties than the counterpart material consolidated by hot isostatic pressing. Although the presence of a dispersion of Y-rich particles is evident, the oxide dispersion strengthened (ODS) Fe–14Cr alloy consolidated by SPS exhibits poor tensile properties. The extensive decoration of the powder particle surfaces with Cr-rich precipitates and the residual porosity appear to be responsible for the impaired properties of this ODS alloy consolidated by SPS.

  17. Microstructural analysis of laser weld fusion zone in Haynes 282 superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Osoba, L.O. [Department of Mechanical and Manufacturing Engineering, University of Manitoba, Winnipeg, Manitoba, R3T 5V6 (Canada); Ding, R.G. [Department of Metallurgy and Materials Engineering, University of Birmingham, Birmingham B15 2TT (United Kingdom); Ojo, O.A., E-mail: ojo@cc.umanitoba.ca [Department of Mechanical and Manufacturing Engineering, University of Manitoba, Winnipeg, Manitoba, R3T 5V6 (Canada)

    2012-03-15

    Analytical electron microscopy and spectroscopy analyses of the fusion zone (FZ) microstructure in autogenous laser beam welded Haynes 282 (HY 282) superalloy were performed. The micro-segregation patterns observed in the FZ indicate that Co, Cr and Al exhibited a nearly uniform distribution between the dendrite core and interdendritic regions while Ti and Mo were rejected into the interdendritic liquid during the weld solidification. Transmission electron diffraction analysis and energy dispersive X-ray microanalysis revealed the second phase particles formed along the FZ interdendritic region to be Ti-Mo rich MC-type carbide particles. Weld FZ solidification cracking, which is sometimes associated with the formation of {gamma}-{gamma}' eutectic in {gamma}' precipitation strengthened nickel-base superalloys, was not observed in the HY 282 superalloy. Modified primary solidification path due to carbon addition in the newly developed superalloy is used to explain preclusion of weld FZ solidification cracking in the material. - Highlights: Black-Right-Pointing-Pointer A newly developed superalloy was welded by CO{sub 2} laser beam joining technique. Black-Right-Pointing-Pointer Electron microscopy characterization of the weld microstructure was performed. Black-Right-Pointing-Pointer Identified interdendritic microconstituents consist of MC-type carbides. Black-Right-Pointing-Pointer Modification of primary solidification path is used to explain cracking resistance.

  18. Effect of tensile mean stress on fatigue behavior of single-crystal and directionally solidified superalloys

    Science.gov (United States)

    Kalluri, Sreeramesh; Mcgaw, Michael A.

    1990-01-01

    Two nickel base superalloys, single crystal PWA 1480 and directionally solidified MAR-M 246 + Hf, were studied in view of the potential usage of the former and usage of the latter as blade materials for the turbomachinery of the space shuttle main engine. The baseline zero mean stress (ZMS) fatigue life (FL) behavior of these superalloys was established, and then the effect of tensile mean stress (TMS) on their FL behavior was characterized. At room temperature these superalloys have lower ductilities and higher strengths than most polycrystalline engineering alloys. The cycle stress-strain response was thus nominally elastic in most of the fatigue tests. Therefore, a stress range based FL prediction approach was used to characterize both the ZMS and TMS fatigue data. In the past, several researchers have developed methods to account for the detrimental effect of tensile mean stress on the FL for polycrystalline engineering alloys. However, the applicability of these methods to single crystal and directionally solidified superalloys has not been established. In this study, these methods were applied to characterize the TMS fatigue data of single crystal PWA 1480 and directionally solidified MAR-M 246 + Hf and were found to be unsatisfactory. Therefore, a method of accounting for the TMS effect on FL, that is based on a technique proposed by Heidmann and Manson was developed to characterize the TMS fatigue data of these superalloys. Details of this method and its relationship to the conventionally used mean stress methods in FL prediction are discussed.

  19. Microstructural analysis of laser weld fusion zone in Haynes 282 superalloy

    International Nuclear Information System (INIS)

    Osoba, L.O.; Ding, R.G.; Ojo, O.A.

    2012-01-01

    Analytical electron microscopy and spectroscopy analyses of the fusion zone (FZ) microstructure in autogenous laser beam welded Haynes 282 (HY 282) superalloy were performed. The micro-segregation patterns observed in the FZ indicate that Co, Cr and Al exhibited a nearly uniform distribution between the dendrite core and interdendritic regions while Ti and Mo were rejected into the interdendritic liquid during the weld solidification. Transmission electron diffraction analysis and energy dispersive X-ray microanalysis revealed the second phase particles formed along the FZ interdendritic region to be Ti–Mo rich MC-type carbide particles. Weld FZ solidification cracking, which is sometimes associated with the formation of γ–γ' eutectic in γ' precipitation strengthened nickel-base superalloys, was not observed in the HY 282 superalloy. Modified primary solidification path due to carbon addition in the newly developed superalloy is used to explain preclusion of weld FZ solidification cracking in the material. - Highlights: ► A newly developed superalloy was welded by CO 2 laser beam joining technique. ► Electron microscopy characterization of the weld microstructure was performed. ► Identified interdendritic microconstituents consist of MC-type carbides. ► Modification of primary solidification path is used to explain cracking resistance.

  20. Influence of Short-time Oxidation on Corrosion Properties of Directionally Solidified Superalloys with Different Orientations

    Directory of Open Access Journals (Sweden)

    MA Luo-ning

    2016-07-01

    Full Text Available In order to investigate the corrosion performance on intersecting and longitudinal surfaces of unoxidized and oxidized directionally solidified superalloys, Ni-base directionally solidified superalloy DZ125 and Co-base directionally solidified superalloy DZ40M were selected. Oxidation behavior on both alloys with different orientations was investigated at 1050℃ at different times, simulating the oxidation process of vanes or blades in service; subsequent electrochemical performance in 3.5%NaCl aqueous solution was studied on two orientations of unoxidized and oxidized alloys, simulating the corrosion process of superalloy during downtime. The results show that grain boundaries and sub-boundaries of directionally solidified superalloys are susceptible to corrosion and thus longitudinal surface with lower area fraction of grain boundaries has higher corrosion resistance. Compared to intersecting surface of alloys, the structure of grain boundaries of longitudinal surface is less conducive to diffusion and thus the oxidation rate on longitudinal surface is lower. Formation of oxide layers on alloys after short-time oxidation provides protective effect and enhances the corrosion resistance.

  1. Efficient real time OD matrix estimation based on principal component analysis

    NARCIS (Netherlands)

    Djukic, T.; Flötteröd, G.; Van Lint, H.; Hoogendoorn, S.P.

    2012-01-01

    In this paper we explore the idea of dimensionality reduction and approximation of OD demand based on principal component analysis (PCA). First, we show how we can apply PCA to linearly transform the high dimensional OD matrices into the lower dimensional space without significant loss of accuracy.

  2. Microstructure and mechanical properties of friction stir welded 9Cr ODS steel

    International Nuclear Information System (INIS)

    Min, Hyoung Kee; Kang, Suk Hoon; Noh, Sanghoon; Lee, Jung Gu; Jang, Jinsung; Kim, Tae Kyu

    2013-01-01

    It is well known that the welding of ODS steel with a conventional melting.solidification process is not adequate to reserve nano-oxide particles in the matrix homogeneously. To reserve nano-oxide particles in the matrix homogeneously, friction stir welding (FSW) is the most promising technique to join ODS alloys. In this study, the effects of FSW on the microstructure and mechanical properties of a ODS steel were studied to apply the FSW process to 9Cr ODS steels. Microstructures were observed by means of optical microscopy, electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). A tensile test and hardness test were carried out to the investigate mechanical properties. FSW could successfully produce defect-free welds on ODS plates. FSW produced a fine grain structure consisting of ferrite and martensite. Tensile strengths and elongations of the SZs were excellent at 298 K, compared to those of the BM. This study suggests that FSW might be an appropriate welding method of ODS steels. Oxide dispersion strengthened (ODS) ferritic-martensitic (FM) steel containing 9 wt%Cr is a promising candidate material for high temperature components operating in aggressive environments such as nuclear fusion and fission systems because of the excellent elevated temperature strength, corrosion and radiation resistance. These characteristics come from microstructures consisting of fine grains and nano-oxide particles dispersed in high number density. However, for more applications of ODS steel in nuclear systems, its weldability is the one of the barrier to be solved

  3. 46 CFR 280.8 - Certain ODS agreement provisions not affected.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Certain ODS agreement provisions not affected. 280.8 Section 280.8 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION REGULATIONS AFFECTING... LINER OPERATORS § 280.8 Certain ODS agreement provisions not affected. The provisions of this part are...

  4. OD (order-disorder) character of the crystal structure of maucherite Ni8As11

    DEFF Research Database (Denmark)

    Makovicky, Emil; Merlino, Stefano

    2009-01-01

    Maucherite Ni11As8 has been found to be an OD (order-disorder) structure consisting of unit layers, which display stacking orientation disorder. Maucherite is composed of OD layers of one kind, with layer symmetry P( )m2 (the bracketed element is perpendicular to the layer), the simplest, uniform...

  5. ODS-materials for high temperature applications in advanced nuclear systems

    Directory of Open Access Journals (Sweden)

    C.C. Eiselt

    2016-12-01

    Full Text Available A ferritic ODS-alloy (Fe-14Cr-1W-0.25Ti has been manufactured by application of the powder metallurgical production route involving at first mechanical alloying of ∼10kg pre-alloyed steel powder together with an Y2O3 addition for 12h in a high energy industrial ball mill under hydrogen atmosphere at the company ZOZ GmbH. As a next step, one part of the alloyed powder was hot extruded into rods while another portion was hot isostatically pressed into plates. Both materials were then heat treated. A characterization program on these ODS-alloy production forms included microstructural and mechanical investigations: SANS and TEM assume the existence of Y2Ti2O7 nano clusters and show a bimodal distribution of ODS-particle sizes in both ODS variants. EBSD maps showed a strong 〈110〉 texture corresponding to the α fiber for the hot extruded ODS and a slight 〈001〉 texture for the hipped ODS material. Fracture toughness tests in different specimen orientations (extruded ODS with mini 0.2T C(T specimens together with Charpy impact tests revealed anisotropic mechanical properties: Promising (fracture toughness levels were obtained in the specimen orientation perpendicular to the extrusion direction, while the toughness levels remained low in extrusion direction and generally for the hipped ODS material at all test temperatures. The fracture toughness tests were performed according to ASTM E 1921 and 1820 standards.

  6. A major locus on mouse chromosome 18 controls XX sex reversal in Odd Sex (Ods) mice.

    Science.gov (United States)

    Qin, Yangjun; Poirier, Christophe; Truong, Cavatina; Schumacher, Armin; Agoulnik, Alexander I; Bishop, Colin E

    2003-03-01

    We have previously reported a dominant mouse mutant, Odd sex (Ods), in which XX Ods/+ mice on the FVB/N background show complete sex reversal, associated with expression of Sox9 in the fetal gonads. Remarkably, when crossed to the A/J strain approximately 95% of the (AXFVB) F(1) XX Ods/+ mice developed as fully fertile, phenotypic females, the remainder developing as males or hermaphrodites. Using a (AXFVB) F(2) population, we conducted a genome-wide linkage scan to identify the number and chromosomal location of potential Ods modifier genes. A single major locus termed Odsm1 was mapped to chromosome 18, tightly linked to D18Mit189 and D18Mit210. Segregation at this locus could account for the presence of sex reversal in 100% of XX Ods/+ mice which develop as males, for the absence of sex reversal in approximately 92% of XX Ods/+ mice which develop as females, and for the mixed sexual phenotype in approximately 72% of XX Ods/+ mice that develop with ambiguous genitalia. We propose that homozygosity for the FVB-derived allele strongly favors Ods sex reversal, whereas homozygosity for the A/J-derived allele inhibits it. In mice heterozygous at Odsm1, the phenotypic outcome, male, female or hermaphrodite, is determined by a complex interaction of several minor modifying loci. The close proximity of Smad2, Smad7 and Smad4 to D18Mit189/210 provides a potential mechanism through which Odsm1 might act.

  7. Disintegration of liquid sheets

    Science.gov (United States)

    Mansour, Adel; Chigier, Norman

    1990-01-01

    The development, stability, and disintegration of liquid sheets issuing from a two-dimensional air-assisted nozzle is studied. Detailed measurements of mean drop size and velocity are made using a phase Doppler particle analyzer. Without air flow the liquid sheet converges toward the axis as a result of surface tension forces. With airflow a quasi-two-dimensional expanding spray is formed. The air flow causes small variations in sheet thickness to develop into major disturbances with the result that disruption starts before the formation of the main break-up region. In the two-dimensional variable geometry air-blast atomizer, it is shown that the air flow is responsible for the formation of large, ordered, and small chaotic 'cell' structures.

  8. Safety advice sheets

    CERN Multimedia

    HSE Unit

    2013-01-01

    You never know when you might be faced with questions such as: when/how should I dispose of a gas canister? Where can I find an inspection report? How should I handle/store/dispose of a chemical substance…?   The SI section of the DGS/SEE Group is primarily responsible for safety inspections, evaluating the safety conditions of equipment items, premises and facilities. On top of this core task, it also regularly issues “Safety Advice Sheets” on various topics, designed to be of assistance to users but also to recall and reinforce safety rules and procedures. These clear and concise sheets, complete with illustrations, are easy to display in the appropriate areas. The following safety advice sheets have been issued so far: Other sheets will be published shortly. Suggestions are welcome and should be sent to the SI section of the DGS/SEE Group. Please send enquiries to general-safety-visits.service@cern.ch.

  9. Data acquisition at the BGO-OD experiment

    Energy Technology Data Exchange (ETDEWEB)

    Hammann, Daniel [Physikalisches Institut, Universitaet Bonn (Germany); Collaboration: BGO-OD-Collaboration

    2016-07-01

    The BGO-OD experiment, located at the 3.5 GeV electron accelerator ELSA in Bonn, is investigating photo-production of mesons. It combines a highly segmented electromagnetic calorimeter, covering almost 4π, with an open dipole spectrometer for the forward angles. To acquire the data from the various detectors of the setup, a distributed data acquisition system was set up. A global trigger signal is distributed using a dedicated FPGA based synchronization system. This trigger signal is also used as hardware reference for all time measurements. Offline reconstruction of the trigger logic allows to further improve the time reference in software. An even more precise timing reference can be derived from the ELSA acceleration frequency. A dedicated TDC measures the phase difference between the global trigger signal and the ELSA frequency. With this the knowledge of the event time is only limited by the intrinsic resolution of the TDC and the electron bunch length.

  10. Isotope Effects in the Reactions of Chloroform Isotopologues with Cl, OH and OD

    DEFF Research Database (Denmark)

    Nilsson, Elna Johanna Kristina; Johnson, Matthew Stanley; Nielsen, Claus J.

    2009-01-01

    The kinetic isotope effects in the reactions of CHCl3, CDCl3, and 13CHCl3 with Cl, OH, and OD radicals have been determined in relative rate experiments at 298 ( 1 K and atmospheric pressure monitored by long path FTIR spectroscopy. The spectra were analyzed using a nonlinear least-squares spectral.......002, kCHCl3+OD/kCDCl3+OD ) 3.95 ( 0.03, and kCHCl3+OD/k13CHCl3+OD ) 1.032 ( 0.004. Larger isotope effects in the OH reactions than in the Cl reactions are opposite to the trends for CH4 and CH3Cl reported in the literature. The origin of these differences was investigated using electronic structure...

  11. Ultra-high temperature tensile properties of ODS steel claddings under severe accident conditions

    Energy Technology Data Exchange (ETDEWEB)

    Yano, Y., E-mail: yano.yasuhide@jaea.go.jp [Japan Atomic Energy Agency, 4002, Narita-cho, Oarai-machi, Ibaraki, 311-1393 (Japan); Tanno, T.; Oka, H.; Ohtsuka, S.; Inoue, T.; Kato, S.; Furukawa, T.; Uwaba, T.; Kaito, T. [Japan Atomic Energy Agency, 4002, Narita-cho, Oarai-machi, Ibaraki, 311-1393 (Japan); Ukai, S.; Oono, N. [Materials Science and Engineering, Faculty of Engineering, Hokkaido University, N13, W-8, Kita-ku, Sapporo, Hokkaido, 060-8628 (Japan); Kimura, A. [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Hayashi, S. [Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Torimaru, T. [Nippon Nuclear Fuel Development Co., Ltd., 2163, Narita-cho, Oarai-machi, Ibaraki, 311-1313 (Japan)

    2017-04-15

    Ultra-high temperature ring tensile tests were performed to investigate the tensile behavior of oxide dispersion strengthened (ODS) steel claddings and wrapper materials under severe accident conditions with temperatures ranging from room temperature to 1400 °C which is close to the melting point of core materials. The experimental results showed that the tensile strength of 9Cr-ODS steel claddings was highest in the core materials at ultra-high temperatures of 900–1200 °C, but there was significant degradation in the tensile strength of 9Cr-ODS steel claddings above 1200 °C. This degradation was attributed to grain boundary sliding deformation with γ/δ transformation, which is associated with reduced ductility. By contrast, the tensile strength of recrystallized 12Cr-ODS and FeCrAl-ODS steel claddings retained its high value above 1200 °C, unlike the other tested materials.

  12. Ultra-high temperature tensile properties of ODS steel claddings under severe accident conditions

    Science.gov (United States)

    Yano, Y.; Tanno, T.; Oka, H.; Ohtsuka, S.; Inoue, T.; Kato, S.; Furukawa, T.; Uwaba, T.; Kaito, T.; Ukai, S.; Oono, N.; Kimura, A.; Hayashi, S.; Torimaru, T.

    2017-04-01

    Ultra-high temperature ring tensile tests were performed to investigate the tensile behavior of oxide dispersion strengthened (ODS) steel claddings and wrapper materials under severe accident conditions with temperatures ranging from room temperature to 1400 °C which is close to the melting point of core materials. The experimental results showed that the tensile strength of 9Cr-ODS steel claddings was highest in the core materials at ultra-high temperatures of 900-1200 °C, but there was significant degradation in the tensile strength of 9Cr-ODS steel claddings above 1200 °C. This degradation was attributed to grain boundary sliding deformation with γ/δ transformation, which is associated with reduced ductility. By contrast, the tensile strength of recrystallized 12Cr-ODS and FeCrAl-ODS steel claddings retained its high value above 1200 °C, unlike the other tested materials.

  13. Ice Sheets & Ice Cores

    DEFF Research Database (Denmark)

    Mikkelsen, Troels Bøgeholm

    Since the discovery of the Ice Ages it has been evident that Earth’s climate is liable to undergo dramatic changes. The previous climatic period known as the Last Glacial saw large oscillations in the extent of ice sheets covering the Northern hemisphere. Understanding these oscillations known....... The first part concerns time series analysis of ice core data obtained from the Greenland Ice Sheet. We analyze parts of the time series where DO-events occur using the so-called transfer operator and compare the results with time series from a simple model capable of switching by either undergoing...

  14. Energy information sheets

    Energy Technology Data Exchange (ETDEWEB)

    1993-12-02

    The National Energy Information Center (NEIC), as part of its mission, provides energy information and referral assistance to Federal, State, and local governments, the academic community, business and industrial organizations, and the general public. Written for the general public, the EIA publication Energy Information Sheets was developed to provide information on various aspects of fuel production, prices, consumption and capability. The information contained herein pertains to energy data as of December 1991. Additional information on related subject matter can be found in other EIA publications as referenced at the end of each sheet.

  15. Thermodynamic assessment of liquid composition change during solidification and its effect on freckle formation in superalloys

    International Nuclear Information System (INIS)

    Long Zhengdong; Liu Xingbo; Yang Wanhong; Chang, K.-M.; Barbero, Ever

    2004-01-01

    The solidification macrosegregation, i.e. freckle, becomes more and more concerned with ever increasing demand for the large ingot size of superalloys. The evaluation of freckle formation is very difficult because of the less understanding of freckle formation mechanism and complex solidification behaviors of multi-component superalloys. The macrostructure of typical Nb-bearing and Ti-bearing superalloys in horizontally directional solidification and vacuum arc remelting (VAR) ingots were investigated to clarify the freckle formation mechanism. The thermodynamic approach was proposed to simulate the solidification behaviors. The relative Ra numbers, a reliable criterion, of freckle formation for some alloys were obtained based on the results of thermodynamic calculations. This thermodynamic approach was evaluated through comparison of the calculations from semi-experimental results. The Ra numbers obtained by thermodynamic approach are in good agreement with the ingot size capability of the industry melting shops, which is limited mainly by freckle defects

  16. A comparative study of the corrosion resistance of incoloy MA 956 and PM 2000 superalloys

    Directory of Open Access Journals (Sweden)

    Maysa Terada

    2010-12-01

    Full Text Available Austenitic stainless steels, titanium and cobalt alloys are widely used as biomaterials. However, new medical devices require innovative materials with specific properties, depending on their application. The magnetic properties are among the properties of interest for some biomedical applications. However, due to the interaction of magnetic materials with Magnetic Resonance Image equipments they might used only as not fixed implants or for medical devices. The ferromagnetic superalloys, Incoloy MA 956 and PM 2000, produced by mechanical alloying, have similar chemical composition, high corrosion resistance and are used in high temperature applications. In this study, the corrosion resistance of these two ferritic superalloys was compared in a phosphate buffer solution. The electrochemical results showed that both superalloys are passive in this solution and the PM 2000 present a more protective passive film on it associated to higher impedances than the MA 956.

  17. A new method in prediction of TCP phases formation in superalloys

    International Nuclear Information System (INIS)

    Mousavi Anijdan, S.H.; Bahrami, A.

    2005-01-01

    The purpose of this investigation is to develop a model for prediction of topologically closed-packed (TCP) phases formation in superalloys. In this study, artificial neural networks (ANN), using several different network architectures, were used to investigate the complex relationships between TCP phases and chemical composition of superalloys. In order to develop an optimum ANN structure, more than 200 experimental data were used to train and test the neural network. The results of this investigation shows that a multilayer perceptron (MLP) form of the neural networks with one hidden layer and 10 nodes in the hidden layer has the lowest mean absolute error (MAE) and can be accurately used to predict the electron-hole number (N v ) and TCP phases formation in superalloys

  18. Degradation of creep properties in a long-term thermally exposed nickel base superalloy

    International Nuclear Information System (INIS)

    Zrnik, J.; Strunz, P.; Vrchovinsky, V.; Muransky, O.; Novy, Z.; Wiedenmann, A.

    2004-01-01

    When exposed for long time at elevated temperatures of 430 and 650 deg. C the nickel base superalloy EI 698 VD can experience a significant decrease in creep resistance. The cause of the creep degradation of nickel base superalloy is generally attributed to the microstructural instability at prolonged high temperature exposure. In this article, the creep-life data, generated on long thermally exposed nickel base superalloy EI698 VD were related to the local microstructural changes observed using SEM and TEM analysing techniques. While structure analysis provided supporting evidence concerning the changes associated with grain boundary carbide precipitation, no persuasive evidence of a morphological and/or dimensional gamma prime change was showed. For clarifying of the role of gamma prime precipitates on alloy on creep degradation, the SANS (small angle neutron scattering) experiment was crucial in the characterization of the bulk-averaged gamma prime morphology and its size distribution with respect to the period of thermal exposure

  19. Zinc-induced embrittlement in nickel-base superalloys by simulation and experiment

    Science.gov (United States)

    Otis, Richard; Waje, Mahesh; Lindwall, Greta; Jefferson, Tiffany; Lange, Jeremy; Liu, Zi-Kui

    2017-09-01

    The high cost of Re has driven interest in processes for recovering Re from scrap superalloy parts. In this work thermodynamic modelling is used to study Zn-induced embrittlement of a superalloy and to direct experiments. Treating superalloy powder with Zn vapour reduces the average particle size after milling from approximately ?m to 0.5-10 ?m, vs. ?m for untreated powder. Simulations predict the required treatment time to increase with temperature. Agreement between predictions and experiments suggests that an embrittling liquid forms in less than an hour of Zn vapour treatment between 950-1000 ?C and partial pressures of Zn between 14-34 kPa (2-5 psi).

  20. Alloying effects of refractory elements in the dislocation of Ni-based single crystal superalloys

    Directory of Open Access Journals (Sweden)

    Shiyu Ma

    2016-12-01

    Full Text Available The alloying effects of W, Cr and Re in the [100] (010 edge dislocation cores (EDC of Ni-based single crystal superalloys are investigated using first-principles based on the density functional theory (DFT. The binding energy, Mulliken orbital population, density of states, charge density and radial distribution functions are discussed, respectively. It is clearly demonstrated that the addition of refractory elements improves the stability of the EDC systems. In addition, they can form tougher bonds with their nearest neighbour (NN Ni atoms, which enhance the mechanical properties of the Ni-based single crystal superalloys. Through comparative analysis, Cr-doped system has lower binding energy, and Cr atom has evident effect to improve the systemic stability. However, Re atom has the stronger alloying effect in Ni-based single crystal superalloys, much more effectively hindering dislocation motion than W and Cr atoms.

  1. A Review on Inertia and Linear Friction Welding of Ni-Based Superalloys

    Science.gov (United States)

    Chamanfar, Ahmad; Jahazi, Mohammad; Cormier, Jonathan

    2015-04-01

    Inertia and linear friction welding are being increasingly used for near-net-shape manufacturing of high-value materials in aerospace and power generation gas turbines because of providing a better quality joint and offering many advantages over conventional fusion welding and mechanical joining techniques. In this paper, the published works up-to-date on inertia and linear friction welding of Ni-based superalloys are reviewed with the objective to make clarifications on discrepancies and uncertainties reported in literature regarding issues related to these two friction welding processes as well as microstructure, texture, and mechanical properties of the Ni-based superalloy weldments. Initially, the chemical composition and microstructure of Ni-based superalloys that contribute to the quality of the joint are reviewed briefly. Then, problems related to fusion welding of these alloys are addressed with due consideration of inertia and linear friction welding as alternative techniques. The fundamentals of inertia and linear friction welding processes are analyzed next with emphasis on the bonding mechanisms and evolution of temperature and strain rate across the weld interface. Microstructural features, texture development, residual stresses, and mechanical properties of similar and dissimilar polycrystalline and single crystal Ni-based superalloy weldments are discussed next. Then, application of inertia and linear friction welding for joining Ni-based superalloys and related advantages over fusion welding, mechanical joining, and machining are explained briefly. Finally, present scientific and technological challenges facing inertia and linear friction welding of Ni-based superalloys including those related to modeling of these processes are addressed.

  2. Collisionless current sheet equilibria

    Science.gov (United States)

    Neukirch, T.; Wilson, F.; Allanson, O.

    2018-01-01

    Current sheets are important for the structure and dynamics of many plasma systems. In space and astrophysical plasmas they play a crucial role in activity processes, for example by facilitating the release of magnetic energy via processes such as magnetic reconnection. In this contribution we will focus on collisionless plasma systems. A sensible first step in any investigation of physical processes involving current sheets is to find appropriate equilibrium solutions. The theory of collisionless plasma equilibria is well established, but over the past few years there has been a renewed interest in finding equilibrium distribution functions for collisionless current sheets with particular properties, for example for cases where the current density is parallel to the magnetic field (force-free current sheets). This interest is due to a combination of scientific curiosity and potential applications to space and astrophysical plasmas. In this paper we will give an overview of some of the recent developments, discuss their potential applications and address a number of open questions.

  3. Cholera Fact Sheet

    Science.gov (United States)

    ... news-room/fact-sheets/detail/cholera","@context":"http://schema.org","@type":"Article"}; العربية 中文 français русский español ... that includes feedback at the local level and information-sharing at the global level. Cholera cases are ...

  4. Pseudomonas - Fact Sheet

    OpenAIRE

    Public Health Agency

    2012-01-01

    Fact sheet on Pseudomonas, including:What is Pseudomonas?What infections does it cause?Who is susceptible to pseudomonas infection?How will I know if I have pseudomonas infection?How can Pseudomonas be prevented from spreading?How can I protect myself from Pseudomonas?How is Pseudomonas infection treated?

  5. NTPR Fact Sheets

    Science.gov (United States)

    History Documents US Underground Nuclear Test History Reports NTPR Radiation Exposure Reports Enewetak Atoll Cleanup Documents TRAC About Who We Are Our Values History Locations Our Leadership Director Support Center Contact Us FAQ Sheet Links Success Stories Contracts Business Opportunities Current

  6. Production (information sheets)

    NARCIS (Netherlands)

    2007-01-01

    Documentation sheets: Geo energy 2 Integrated System Approach Petroleum Production (ISAPP) The value of smartness 4 Reservoir permeability estimation from production data 6 Coupled modeling for reservoir application 8 Toward an integrated near-wellbore model 10 TNO conceptual framework for "E&P

  7. Hibernia fact sheet

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    This fact sheet gives details of the Hibernia oil field including its location, discovery date, oil company's interests in the project, the recoverable reserves of the two reservoirs, the production system used, capital costs of the project, and overall targets for Canadian benefit. Significant dates for the Hibernia project are listed. (UK)

  8. Ethanol Basics (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2015-01-01

    Ethanol is a widely-used, domestically-produced renewable fuel made from corn and other plant materials. More than 96% of gasoline sold in the United States contains ethanol. Learn more about this alternative fuel in the Ethanol Basics Fact Sheet, produced by the U.S. Department of Energy's Clean Cities program.

  9. Corrosion Behavior of Superalloys in Hot Lithium Molten Salt

    International Nuclear Information System (INIS)

    Cho, Soo-Haeng; Hur, Jin-Mok; Seo, Chung-Seok; Park, Seoung-Won

    2006-01-01

    The Li-reduction process involves the chemical reduction of spent fuel oxides by liquid lithium metal in a molten LiCl salt bath at 650 .deg. C followed by a separate electrochemical reduction of lithium oxide (Li 2 O), which builds up in the salt bath. This process requires a high purity inert gas atmosphere inside remote hot cell nuclear facility to prevent unwanted Li oxidation and fires during the handling of chemically active Li metal. In light of the limitations of the Li-reduction process, a direct electrolytic reduction technology is being developed by KAERI to enhance process safety and economic viability. The electrolytic reduction of spent oxide fuel involves the liberation of oxygen in a molten LiCl electrolyte, which results in a chemically aggressive environment that is too corrosive for typical structural materials. Even so, the electrochemical process vessel must be resilient at ∼ 650 .deg. C in the presence of oxygen to enable high processing rates and an extended service life. But, the mechanism and the rate of the corrosion of metals in LiCl-Li 2 O molten salt under oxidation condition are not clear. In the present work, the corrosion behavior and corrosion mechanism of superalloys have been studied in the molten salt of LiCl-Li 2 O under oxidation condition

  10. Structural Performance of Inconel 625 Superalloy Brazed Joints

    Science.gov (United States)

    Chen, Jianqiang; Demers, Vincent; Cadotte, Eve-Line; Turner, Daniel; Bocher, Philippe

    2017-02-01

    The purpose of this work was to investigate tensile and fatigue behaviors of Inconel 625 superalloy brazed joints after transient liquid-phase bonding process. Brazing was performed in a vacuum furnace using a nickel-based filler metal in a form of paste to join wrought Inconel 625 plates. Mechanical tests were carried out on single-lap joints under various lap distance-to-thickness ratios. The fatigue crack initiation and crack growth modes were examined via metallographic analysis, and the effect of local stress on fatigue life was assessed by finite element simulations. The fatigue results show that fatigue strength and endurance limit increase with overlap distance, leading to a relatively large scatter of results. Fatigue cracks nucleated in the high-stressed region of the weld fillets from brittle eutectic phases or from internal brazing cavities. The present work proposes to rationalize the results by using the local stress at the brazing fillet. When using this local stress, all fatigue-obtained results find themselves on a single S- N curve, providing a design curve for any joint configuration in fatigue solicitation.

  11. High Temperature Deformation Mechanisms in a DLD Nickel Superalloy

    Directory of Open Access Journals (Sweden)

    Sean Davies

    2017-04-01

    Full Text Available The realisation of employing Additive Layer Manufacturing (ALM technologies to produce components in the aerospace industry is significantly increasing. This can be attributed to their ability to offer the near-net shape fabrication of fully dense components with a high potential for geometrical optimisation, all of which contribute to subsequent reductions in material wastage and component weight. However, the influence of this manufacturing route on the properties of aerospace alloys must first be fully understood before being actively applied in-service. Specimens from the nickel superalloy C263 have been manufactured using Powder Bed Direct Laser Deposition (PB-DLD, each with unique post-processing conditions. These variables include two build orientations, vertical and horizontal, and two different heat treatments. The effects of build orientation and post-process heat treatments on the materials’ mechanical properties have been assessed with the Small Punch Tensile (SPT test technique, a practical test method given the limited availability of PB-DLD consolidated material. SPT testing was also conducted on a cast C263 variant to compare with PB-DLD derivatives. At both room and elevated temperature conditions, differences in mechanical performances arose between each material variant. This was found to be instigated by microstructural variations exposed through microscopic and Energy Dispersive X-ray Spectroscopy (EDS analysis. SPT results were also compared with available uniaxial tensile data in terms of SPT peak and yield load against uniaxial ultimate tensile and yield strength.

  12. Kinetics of Grain Growth in 718 Ni-Base Superalloy

    Directory of Open Access Journals (Sweden)

    Huda Z.

    2014-10-01

    Full Text Available The Haynes® 718 Ni-base superalloy has been investigated by use of modern material characterization, metallographic and heat treatment equipment. Grain growth annealing experiments at temperatures in the range of 1050 – 1200 oC (1323–1473K for time durations in the range of 20 min-22h have been conducted. The kinetic equations and an Arrhenius-type equation have been applied to compute the grain-growth exponent n and the activation energy for grain growth, Qg, for the investigated alloy. The grain growth exponent, n, was computed to be in the range of 0.066-0.206; and the n values have been critically discussed in relation to the literature. The activation energy for grain growth, Qg, for the investigated alloy has been computed to be around 440 kJ/mol; and the Qg data for the investigated alloy has been compared with other metals and alloys and ceramics; and critically analyzed in relation to our results.

  13. The precipitation behavior of superalloy ATI Allvac 718Plus

    Energy Technology Data Exchange (ETDEWEB)

    Zickler, Gerald A.; Schnitzer, Ronald; Leitner, Harald [Department of Physical Metallurgy and Materials Testing, Christian Doppler Laboratory Early Stages of Precipitation, Montanuniversitaet Leoben (Austria); Radis, Rene [Christian Doppler Laboratory Early Stages of Precipitation, Institute of Materials Science and Technology, Vienna University of Technology (Austria); Institute for Materials Science and Welding, Graz University of Technology (Austria); Kozeschnik, Ernst [Christian Doppler Laboratory Early Stages of Precipitation, Institute of Materials Science and Technology, Vienna University of Technology (Austria); Stockinger, Martin [Boehler Schmiedetechnik GmbH and Co. KG., Kapfenberg (Austria)

    2010-03-15

    ATI Allvac 718Plus is a novel nickel-based superalloy, which was designed for heavy-duty applications in aerospace gas turbines. The precipitation kinetics of the intermetallic {delta} (Ni{sub 3}Nb) and {gamma}' (Ni{sub 3}(Al,Ti)) phases in this alloy are of scientific as well as technological interest because of their significant influence on the mechanical properties. Important parameters like grain size are controlled by coarse {delta} precipitates located at grain boundaries, whereas small {gamma}' precipitates are responsible for strengthening by precipitation hardening. In the present study, the microstructure is investigated by three-dimensional atom probe tomography and simulated by computer modeling using the thermo-kinetic software MatCalc. The results of numerical simulations and experimental data are compared and critically discussed. It is shown that the chemical compositions of the phases change during isothermal aging, and the precipitation kinetics of {delta} and {gamma}' phases interact with each other as shown in a time temperature precipitation (TTP) plot. The TTP plot shows C-shaped curves with characteristic discontinuities in the temperature range, where simultaneous and concurrent precipitation of the {delta} and {gamma}' phases occurs. This leads to a competition in the diffusion of Nb and Al, which are partly present in both phases. Thus, the present study gives important information on heat treatments for ATI Allvac 718Plus in order to achieve the desired microstructure and mechanical properties. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  14. Niobium-base superalloys via powder metallurgy technology

    International Nuclear Information System (INIS)

    Loria, E.A.

    1987-01-01

    This paper provides some insight into an area that has been neglected, namely the possibility of developing high-strength, niobium-base alloys by improved oxidation resistance via the consolidation of rapidly solidified powders. Powder metallurgy (P/M) is an attractive processing technique because of its flexibility and versatility, and it may provide the alloys with properties and workability not obtainable via metal casting. A critical review of both U.S. and Russian literature is presented along with suggestions on the most promising compositions and processing techniques available to meet these competing goals. Previous work on many niobium alloys reveals that long term properties are retained well above those obtained on nickel-base superalloys. Cast and wrought alloys extend specific strength beyond 1200 0 C (2200 0 F), but lack oxidation resistance. Remarkable oxidation resistance is obtained, however, on miniature castings of certain ternary alloys which are too brittle for any processing. A better understanding of the oxidation mechanism is necessary before the proper P/M (RST) approach is taken on compositions which could provide compatibility between the two competing goals through grain refinement and a homogeneous distribution of the contributory phases. Finally, ways to up-scale production of Nb powder are discussed, including thermodynamic feasibility for the direct reduction of NbCl/sub 5/ in a 1.5 MW plasma reactor

  15. Segregation to grain boundaries in nimonic PE16 superalloy

    International Nuclear Information System (INIS)

    Nettleship, D.J.; Wild, R.K.

    1990-01-01

    Nimonic PE16 alloy is a nickel-based superalloy containing 34 wt.% iron and 16wt.% chromium with additions of molybdenum, titanium and aluminium. It is used in the fuel assembly of the UK advanced gas-cooled reactors (AGR). This component supports significant loads in service and its mechanical integrity is therefore of paramount importance. Mechanical properties may be influenced by the grain size and grain boundary composition, both of which can themselves alter during service. Scanning Auger microscopy is a well-established method for investigating grain boundaries, and has now been applied to the study of PE16. In order to expose PE16 grain boundary surfaces it is necessary to hydrogen charge samples and fracture by pulling in tension at a slow strain rate within the ultra-high vacuum chamber of the Auger microprobe. A series of casts of nimonic PE16 alloy that have received a range of thermal ageing treatments have been fractured in an intergranular manner and the grain boundary composition determined. Segregation of trace and minority elements, particularly Mo and P, has been detected at grain boundaries. Significant variations between different as-manufactured casts were observed, whilst ageing brought about the growth of chromium-rich particles on the grain boundaries. Ductile fracture in PE16 followed a path through Ti(C, N) particles. Many of these particles incorporated large amounts of sulphur. (author)

  16. Friction Freeform Fabrication of Superalloy Inconel 718: Prospects and Problems

    Science.gov (United States)

    Dilip, J. J. S.; Janaki Ram, G. D.

    2014-01-01

    Friction Freeform Fabrication is a new solid-state additive manufacturing process. The present investigation reports a detailed study on the prospects of this process for additive part fabrication in superalloy Inconel 718. Using a rotary friction welding machine and employing alloy 718 consumable rods in solution treated condition, cylindrical-shaped multi-layer friction deposits (10 mm diameter) were successfully produced. In the as-deposited condition, the deposits showed very fine grain size with no grain boundary δ phase. The deposits responded well to direct aging and showed satisfactory room-temperature tensile properties. However, their stress rupture performance was unsatisfactory because of their layered microstructure with very fine grain size and no grain boundary δ phase. The problem was overcome by heat treating the deposits first at 1353 K (1080 °C) (for increasing the grain size) and then at 1223 K (950 °C) (for precipitating the δ phase). Overall, the current study shows that Friction Freeform Fabrication is a very useful process for additive part fabrication in alloy 718.

  17. ISOTHERMAL AND THERMOMECHANICAL FATIGUE OF A NICKEL-BASE SUPERALLOY

    Directory of Open Access Journals (Sweden)

    Carlos Carvalho Engler-Pinto Júnior

    2014-06-01

    Full Text Available Thermal gradients arising during transient regimes of start-up and shutdown operations produce a complex thermal and mechanical fatigue loading which limits the life of turbine blades and other engine components operating at high temperatures. More accurate and reliable assessment under non-isothermal fatigue becomes therefore mandatory. This paper investigates the nickel base superalloy CM 247LC-DS under isothermal low cycle fatigue (LCF and thermomechanical fatigue (TMF. Test temperatures range from 600°C to 1,000°C. The behavior of the alloy is strongly affected by the temperature variation, especially in the 800°C-1,000°C range. The Ramberg-Osgood equation fits very well the observed isothermal behavior for the whole temperature range. The simplified non-isothermal stress-strain model based on linear plasticity proposed to represent the thermo-mechanical fatigue behavior was able to reproduce the observed behavior for both in-phase and out-of-phase TMF cycling.

  18. Microstructural characteristics of high-temperature oxidation in nickel-base superalloy

    International Nuclear Information System (INIS)

    Khalid, F.A.

    1997-01-01

    Superalloys are used for aerospace and nuclear applications where they can withstand high-temperature and severe oxidizing conditions. High-temperature oxidation behavior of a nickel-base superalloy is examined using optical and scanning electron microscopical techniques. The morphology of the oxide layers developed is examined, and EDX microanalysis reveals diffusion of the elements across the oxide-metal interface. Evidence of internal oxidation is presented, and the role of structural defects is considered. The morphology of the oxide-metal interface formed in the specimens exposed in steam and air is examined to elucidate the mechanism of high-temperature oxidation

  19. Mechanical Behavior of Three-Dimensional Braided Nickel-Based Superalloys Synthesized via Pack Cementation

    Science.gov (United States)

    Lippitz, Nicolas; Erdeniz, Dinc; Sharp, Keith W.; Dunand, David C.

    2018-03-01

    Braided tubes of Ni-based superalloys are fabricated via three-dimensional (3-D) braiding of ductile Ni-20Cr (wt pct) wires followed by post-textile gas-phase alloying with Al and Ti to create, after homogenization and aging, γ/ γ' strengthened lightweight, porous structures. Tensile tests reveal an increase in strength by 100 MPa compared to as-braided Ni-20Cr (wt pct). An interrupted tensile test, combined with X-ray tomographic scans between each step, sheds light on the failure behavior of the braided superalloy tubes.

  20. Process of welding gamma prime-strengthened nickel-base superalloys

    Science.gov (United States)

    Speigel, Lyle B.; White, Raymond Alan; Murphy, John Thomas; Nowak, Daniel Anthony

    2003-11-25

    A process for welding superalloys, and particularly articles formed of gamma prime-strengthened nickel-base superalloys whose chemistries and/or microstructures differ. The process entails forming the faying surface of at least one of the articles to have a cladding layer of a filler material. The filler material may have a composition that is different from both of the articles, or the same as one of the articles. The cladding layer is machined to promote mating of the faying surfaces, after which the faying surfaces are mated and the articles welded together. After cooling, the welded assembly is free of thermally-induced cracks.

  1. Rubella - Fact Sheet for Parents

    Science.gov (United States)

    ... and 4 through 6 years Fact Sheet for Parents Color [2 pages] Español: Rubéola The best way ... according to the recommended schedule. Fact Sheets for Parents Diseases and the Vaccines that Prevent Them Chickenpox ...

  2. Effects of manufacturing process on impact properties and microstructures of ODS steels

    Energy Technology Data Exchange (ETDEWEB)

    Tanno, Takashi, E-mail: tanno.takashi@jaea.go.jp; Ohtsuka, Satoshi; Yano, Yasuhide; Kaito, Takeji; Tanaka, Kenya

    2014-12-15

    Oxide dispersion strengthened (ODS) steels are notable advanced alloys with durability to a high-temperature and high-dose neutron irradiation environment because of their good swelling resistance and mechanical properties under neutron irradiation. 9–12Cr-ODS martensite steels have been developed in the Japan Atomic Energy Agency as the primary candidate material for the fast reactor fuel cladding tubes. They would also be good candidates for the fusion reactor blanket material which is exposed to high-dose neutron irradiation. In this work, modification of the manufacturing process of 11Cr-ODS steel was carried out to improve its impact property. Two types of 11Cr-ODS steels were manufactured: pre-mix and full pre-alloy ODS steels. Miniature Charpy impact tests and metallurgical observations were carried out on these steels. The impact properties of full pre-alloy ODS steels were shown to be superior to those of pre-mix ODS steels. It was demonstrated that the full pre-alloy process noticeably improved the microstructure homogeneity (i.e. reduction of inclusions and pores)

  3. Evaluation of mechanical properties and nano-meso structures of 9–11%Cr ODS steels

    Energy Technology Data Exchange (ETDEWEB)

    Tanno, Takashi, E-mail: tanno.takashi@jaea.go.jp [Japan Atomic Energy Agency, Oarai, Ibaraki 311-1393 (Japan); Ohtsuka, Satoshi; Yano, Yasuhide; Kaito, Takeji [Japan Atomic Energy Agency, Oarai, Ibaraki 311-1393 (Japan); Oba, Yojiro; Ohnuma, Masato [National Institute for Materials Science, Tsukuba 305-1195 (Japan); Koyama, Shinichi; Tanaka, Kenya [Japan Atomic Energy Agency, Oarai, Ibaraki 311-1393 (Japan)

    2013-09-15

    Highlights: • We successfully manufactured 11Cr-ODS steels with residual α-ferrite controlled. • Dispersion conditions of nano oxide particles were quantitatively characterized. • Tungsten solid solution could improve only tensile strength of ODS steels at 973 K. • Oxide dispersion strengthening was dominant in creep strength of ODS steels at 973 K. -- Abstract: This study carried out mechanical tests and microstructural characterizations of several 9Cr and 11Cr-ODS tempered martensitic steels. From those results, the appropriate chemical composition range of 11Cr-ODS tempered martensitic steel was discussed from the viewpoint of high temperature strength improvement. It was shown that the residual α-ferrite fraction in 11Cr-ODS steel was successfully controlled to the same level as the 9Cr-ODS steel, which has excellent high temperature strength, by selecting the chemical compositions on the basis of the multi-component phase diagram. The tensile strength decreased with decreasing W content from 2.0 to 1.4 wt%. On the other hand, creep strength at 973 K did not degrade by the decreasing W content. Both tensile strength and creep strength increased with increasing population of the nano-sized oxide particles. Small angle X-ray scattering analysis revealed that titanium and excess oxygen contents were key parameters in order to improve the dispersion conditions of nano-sized oxide particles.

  4. Internal Delorme's Procedure for Treating ODS Associated With Impaired Anal Continence.

    Science.gov (United States)

    Liu, Weicheng; Sturiale, Alessandro; Fabiani, Bernardina; Giani, Iacopo; Menconi, Claudia; Naldini, Gabriele

    2017-12-01

    The aim of this study was to evaluate the medium-term outcomes of internal Delorme's procedure for treating obstructed defecation syndrome (ODS) patients with impaired anal continence. In a retrospective study, 41 ODS patients who underwent internal Delorme's procedure between 2011 and 2015 were divided into 3 subgroups according to their associated symptoms of impaired continence, as urgency, passive fecal incontinence and both, before study. Then the patients' preoperative statuses, perioperative complications, and postoperative outcomes were investigated and collected from standardized questionnaires, including Altomare ODS score, Fecal Incontinence Severity Index (FISI), Patient Assessment of Constipation-Quality of Life Questionnaire (PAC-QoL), and Fecal Incontinence Quality of Life Scale (FIQLS). All results with a 2-tailed P ODS score, FISI, PAC-QoL, and FIQLS in all patients when comparing scores from before the operation with those at the final follow-up. Similar results were also observed in both the urgency subgroup and passive fecal incontinence subgroup, but there were no statistically significant improvements ( P > .05) in Altomare ODS score, FISI, PAC-QoL, or FIQLS in the urgency and passive fecal incontinence subgroups. Anorectal manometry showed the mean value of anal resting pressure increased 20%. Additionally, no major complications occurred. Internal Delorme's procedure is effective without major morbidity for treating ODS associated with urgency or passive fecal incontinence, but it may be less effective for treating ODS associated with both urgency and passive fecal incontinence.

  5. Vitamin C deficiency exerts paradoxical cardiovascular effects in osteogenic disorder Shionogi (ODS) rats.

    Science.gov (United States)

    Vergely, Catherine; Goirand, Françoise; Ecarnot-Laubriet, Aline; Renard, Céline; Moreau, Daniel; Guilland, Jean-Claude; Dumas, Monique; Rochette, Luc

    2004-04-01

    Vitamin C is considered to be a very efficient water-soluble antioxidant, for which several new cardiovascular properties were recently described. The aim of this study was to determine in vivo the effects of a severe depletion of vitamin C on cardiac and vascular variables and reperfusion arrhythmias. For this purpose, we used a mutant strain of Wistar rats, osteogenic disorder Shionogi (ODS). After 15 d of consuming a vitamin C-deficient diet, ODS rats had a 90% decrease in plasma and tissue levels of ascorbate compared with ODS vitamin C-supplemented rats and normal Wistar rats. However, plasma antioxidant capacity, proteins, alpha-tocopherol, urate, catecholamines, lipids, and nitrate were not influenced by the vitamin C deficiency in ODS rats. Moreover, there was no difference between ODS vitamin C-deficient and -supplemented rats in heart rate and arterial pressure. After 5 min of an in vivo regional myocardial ischemia, various severe arrhythmias were observed, but their intensities were not modified by vitamin C in vitamin C-deficient ODS rats. The vascular reactivity, measured in vitro on thoracic arteries, was not altered by ascorbate deficiency in ODS rats. These unexpected results suggest that unidentified compensatory mechanisms play a role in maintaining normal cardiac function and vascular reactivity in vitamin C-deficient rats.

  6. Influence of Normalizing Temperature on the Microstructure and Hardness of 9Cr-1Mo ODS Steel

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Ki Nam; Kim, Tae Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Kyu Tae [Dongguk University, Gyeongju (Korea, Republic of)

    2016-10-15

    Oxide dispersion strengthened(ODS) steel has superior high-temperature strength and creep properties because fine oxide particles having an excellent stability at high temperatures are uniformly distributed in the matrix. ODS steel has being developed for structure materials of sodium fast cooled reactor(SFR) because of its excellent irradiation resistance and mechanical properties. 9Cr-1Mo ODS steel has better high temperature strength and irradiation resistance than common 9Cr-1Mo steel because Y{sub 2}O{sub 3} nano-sized particles which interrupt dislocation movement and grain boundary slip are uniformly dispersed in the martensite matrix. The mechanical properties of the ODS steels are mainly determined by their microstructures, and the microstructure is considerably decided by the heat-treatment conditions. This study focused on the effect of normalizing temperature on microstructure and hardness of 9Cr-1Mo martensitic ODS steel so as to optimize the heat-treatment condition. In this study, the effect of normalizing temperature on mechanical property and microstructures of 9Cr-1Mo martensitic ODS steel was investigated. It was shown that the microhardness was steadily increased with increasing of the normalizing temperature. According to TEM observation, mechanical property of 9Cr-1Mo ODS steel was significantly affected by lath width. These observations, could be useful to understand the relationship between normalizing temperature and microstructure.

  7. Torsional energy levels of CH3OH+/CH3OD+/CD3OD+ studied by zero-kinetic energy photoelectron spectroscopy and theoretical calculations

    International Nuclear Information System (INIS)

    Dai, Zuyang; Gao, Shuming; Wang, Jia; Mo, Yuxiang

    2014-01-01

    The torsional energy levels of CH 3 OH + , CH 3 OD + , and CD 3 OD + have been determined for the first time using one-photon zero kinetic energy photoelectron spectroscopy. The adiabatic ionization energies for CH 3 OH, CH 3 OD, and CD 3 OD are determined as 10.8396, 10.8455, and 10.8732 eV with uncertainties of 0.0005 eV, respectively. Theoretical calculations have also been performed to obtain the torsional energy levels for the three isotopologues using a one-dimensional model with approximate zero-point energy corrections of the torsional potential energy curves. The calculated values are in good agreement with the experimental data. The barrier height of the torsional potential energy without zero-point energy correction was calculated as 157 cm −1 , which is about half of that of the neutral (340 cm −1 ). The calculations showed that the cation has eclipsed conformation at the energy minimum and staggered one at the saddle point, which is the opposite of what is observed in the neutral molecule. The fundamental C–O stretch vibrational energy level for CD 3 OD + has also been determined. The energy levels for the combinational excitation of the torsional vibration and the fundamental C–O stretch vibration indicate a strong torsion-vibration coupling

  8. Film sheet cassette

    International Nuclear Information System (INIS)

    1981-01-01

    A novel film sheet cassette is described for handling CAT photographic films under daylight conditions and facilitating their imaging. A detailed description of the design and operation of the cassette is given together with appropriate illustrations. The resulting cassette is a low-cost unit which is easily constructed and yet provides a sure light-tight seal for the interior contents of the cassette. The individual resilient fingers on the light-trap permit the ready removal of the slide plate for taking pictures. The stippled, non-electrostatic surface of the pressure plate ensures an air layer and free slidability of the film for removal and withdrawal of the film sheet. The advantage of the daylight system is that a darkroom need not be used for inserting and removing the film in and out of the cassette resulting in a considerable time saving. (U.K.)

  9. Clean Cities Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)

    2004-01-01

    This fact sheet explains the Clean Cities Program and provides contact information for all coalitions and regional offices. It answers key questions such as: What is the Clean Cities Program? What are alternative fuels? How does the Clean Cities Program work? What sort of assistance does Clean Cities offer? What has Clean Cities accomplished? What is Clean Cities International? and Where can I find more information?

  10. Information sheets on energy

    International Nuclear Information System (INIS)

    2004-01-01

    These sheets, presented by the Cea, bring some information, in the energy domain, on the following topics: the world energy demand and the energy policy in France and in Europe, the part of the nuclear power in the energy of the future, the greenhouse gases emissions and the fight against the greenhouse effect, the carbon dioxide storage cost and the hydrogen economy. (A.L.B.)

  11. Biomolecular Science (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2012-04-01

    A brief fact sheet about NREL Photobiology and Biomolecular Science. The research goal of NREL's Biomolecular Science is to enable cost-competitive advanced lignocellulosic biofuels production by understanding the science critical for overcoming biomass recalcitrance and developing new product and product intermediate pathways. NREL's Photobiology focuses on understanding the capture of solar energy in photosynthetic systems and its use in converting carbon dioxide and water directly into hydrogen and advanced biofuels.

  12. Sheet pinch devices

    International Nuclear Information System (INIS)

    Anderson, O.A.; Baker, W.R.; Ise, J. Jr.; Kunkel, W.B.; Pyle, R.V.; Stone, J.M.

    1958-01-01

    Three types of sheet-like discharges are being studied at Berkeley. The first of these, which has been given the name 'Triax', consists of a cylindrical plasma sleeve contained between two coaxial conducting cylinders A theoretical analysis of the stability of the cylindrical sheet plasma predicts the existence of a 'sausage-mode' instability which is, however, expected to grow more slowly than in the case of the unstabilized linear pinch (by the ratio of the radial dimensions). The second pinch device employs a disk shaped discharge with radial current guided between flat metal plates, this configuration being identical to that of the flat hydromagnetic capacitor without external magnetic field. A significant feature of these configurations is the absence of a plasma edge, i.e., there are no regions of sharply curved magnetic field lines anywhere in these discharges. The importance of this fact for stability is not yet fully investigated theoretically. As a third configuration a rectangular, flat pinch tube has been constructed, and the behaviour of a flat plasma sheet with edges is being studied experimentally

  13. The BGO Calorimeter of BGO-OD Experiment

    International Nuclear Information System (INIS)

    Bantes, B; Bayadilov, D; Bella, A; Bielefeldt, P; Bieling, J; Bleckwenn, M; Dutz, H; Elsner, D; Freyermuth, O; Beck, R; Becker, M; Böse, S; Braghieri, A; Brinkmann, K-Th; Friedrich, S; Burdeynyi, D; Curciarello, F; Leo, V De; Salvo, R Di; Fantini, A

    2015-01-01

    The BGO Rugby Ball is a large solid angle electromagnetic calorimeter now installed in the ELSA Facility in Bonn. The BGO is operating in the BGO-OD experiment aiming to study meson photoproduction off proton and neutron induced by a Bremsstrahlung polarized gamma beam of energies from 0.2 to 3.2 GeV and an intensity of 5 × 10 7 photons per second. The scintillating material characteristics and the photomultiplier read-out make this detector particularly suited for the detection of medium energy photons and electrons with very good energy resolution. The detector has been equipped with a new electronics read-out system, consisting of 30 sampling ADC Wie-Ne-R modules which perform the off-line reconstruction of the signal start-time allowing for a good timing resolution. Performances in linearity, resolution and time response have been carefully tested at the Beam Test Facility of the INFN National Laboratories in Frascati by using a matrix of 7 BGO crystals coupled to photomultipliers and equipped with the Wie-Ne-R sampling ADCs

  14. Defining clusters in APT reconstructions of ODS steels.

    Science.gov (United States)

    Williams, Ceri A; Haley, Daniel; Marquis, Emmanuelle A; Smith, George D W; Moody, Michael P

    2013-09-01

    Oxide nanoclusters in a consolidated Fe-14Cr-2W-0.3Ti-0.3Y₂O₃ ODS steel and in the alloy powder after mechanical alloying (but before consolidation) are investigated by atom probe tomography (APT). The maximum separation method is a standard method to define and characterise clusters from within APT data, but this work shows that the extent of clustering between the two materials is sufficiently different that the nanoclusters in the mechanically alloyed powder and in the consolidated material cannot be compared directly using the same cluster selection parameters. As the cluster selection parameters influence the size and composition of the clusters significantly, a procedure to optimise the input parameters for the maximum separation method is proposed by sweeping the d(max) and N(min) parameter space. By applying this method of cluster parameter selection combined with a 'matrix correction' to account for trajectory aberrations, differences in the oxide nanoclusters can then be reliably quantified. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. High-temperature and low-stress creep anisotropy of single-crystal superalloys

    Czech Academy of Sciences Publication Activity Database

    Jacome, L. A.; Nortershauser, P.; Heyer, J. K.; Lahni, A.; Frenzel, J.; Dlouhý, Antonín; Somsen, C.; Eggeler, G.

    2013-01-01

    Roč. 61, č. 8 (2013), s. 2926-2943 ISSN 1359-6454 R&D Projects: GA ČR(CZ) GA202/09/2073 Institutional support: RVO:68081723 Keywords : superalloy single crystals * creep anisotropy * rafting * dislocations * deformation mechanisms Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.940, year: 2013

  16. σ and η Phase formation in advanced polycrystalline Ni-base superalloys

    Energy Technology Data Exchange (ETDEWEB)

    Antonov, Stoichko, E-mail: santonov@hawk.iit.edu [Illinois Institute of Technology, 10 W. 32nd Street, Chicago, IL 60616 (United States); Huo, Jiajie; Feng, Qiang [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Isheim, Dieter; Seidman, David N. [Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL 60208 (United States); Northwestern University Center for Atom Probe Tomography (NUCAPT), 2220 Campus Drive, Evanston, IL 60208 (United States); Helmink, Randolph C.; Sun, Eugene [Rolls-Royce Corporation, 450 S. Meridian Street, Indianapolis, IN 46225 (United States); Tin, Sammy [Illinois Institute of Technology, 10 W. 32nd Street, Chicago, IL 60616 (United States)

    2017-02-27

    In polycrystalline Ni-base superalloys, grain boundary precipitation of secondary phases can be significant due to the effects they pose on the mechanical properties. As new alloying concepts for polycrystalline Ni-base superalloys are being developed to extend their temperature capability, the effect of increasing levels of Nb alloying additions on long term phase stability and the formation of topologically close packed (TCP) phases needs to be studied. Elevated levels of Nb can result in increased matrix supersaturation and promote the precipitation of secondary phases. Long term thermal exposures on two experimental powder processed Ni-base superalloys containing various levels of Nb were completed to assess the stability and precipitation of TCP phases. It was found that additions of Nb promoted the precipitation of η-Ni{sub 6}AlNb along the grain boundaries in powder processed, polycrystalline Ni-base superalloys, while reduced Nb levels favored the precipitation of blocky Cr and Mo – rich σ phase precipitates along the grain boundary. Evaluation of the thermodynamic stability of these two phases in both alloys using Thermo-calc showed that while σ phase predictions are fairly accurate, predictions of the η phase are limited.

  17. Creep deformation and microstructural examination of a prior thermally exposed nickel base superalloy

    Czech Academy of Sciences Publication Activity Database

    Zrník, J.; Strunz, Pavel; Vrchovinský, V.; Muránsky, O.; Horňák, P.; Wiedenmann, A.

    2004-01-01

    Roč. 274 (2004), s. 925-930 ISSN 1013-9826 R&D Projects: GA AV ČR KSK1010104 Keywords : superalloy * thermal exposition * creep Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.278, year: 2004

  18. SANS investigation of precipitate microstructure in nickel-base superalloys Waspaloy and DT750

    Czech Academy of Sciences Publication Activity Database

    Strunz, Pavel; Zrník, J.; Seliga, T.; Penkalla, H.J.

    2006-01-01

    Roč. 2, č. 23 (2006), s. 363-368 ISSN 0044-2968 R&D Projects: GA ČR GA202/06/0601 Institutional research plan: CEZ:AV0Z10480505 Keywords : small-angle-neutron scattering * superalloys * precipitation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.897, year: 2006

  19. Ledges and grooves at γ/γ′ interfaces of single crystal superalloys

    Czech Academy of Sciences Publication Activity Database

    Parsa, A. B.; Wollgramm, P.; Buck, H.; Kostka, A.; Somsen, C.; Dlouhý, Antonín; Eggeler, G.

    2015-01-01

    Roč. 90, MAY (2015), s. 105-117 ISSN 1359-6454 R&D Projects: GA ČR(CZ) GA14-22834S Institutional support: RVO:68081723 Keywords : Ni-base single crystal superalloys * γ/γ′ interfaces * Interface dislocations * Rafting * Grooves Subject RIV: JG - Metallurgy Impact factor: 5.058, year: 2015

  20. Fundamental studies of electron beam welding of heat-resistant superalloys for nuclear plants, 5

    International Nuclear Information System (INIS)

    Arata, Yoshiaki; Terai, Kiyohide; Nagai, Hiroyoshi; Shimizu, Shigeki; Aota, Toshiichi.

    1978-01-01

    In this paper, the mechanical properties of base metal, its electron beam and TIG weld joint of superalloys for nuclear plants were made clear and compared with each other. As a result, it has been clarified that electron beam weld joint is superior to TIG weld joint and nearly comparable to base metal. (author)

  1. Microstructural study of weld fusion zone of TIG welded IN 738LC nickel-based superalloy

    International Nuclear Information System (INIS)

    Ojo, O.A.; Richards, N.L.; Chaturvedi, M.C.

    2004-01-01

    The weld fusion zone microstructure of a commercial aerospace superalloy IN 738 was examined. Elemental segregation induced interdendritic microconstituents were identified to include terminal solidification product M 3 B 2 and Ni 7 Zr 2 in association with γ-γ' eutectic constituent, which require proper consideration during the development of optimum post weld heat treatment

  2. High temperature oxidation characteristics of developed Ni-Cr-W superalloys in air

    International Nuclear Information System (INIS)

    Suzuki, Tomio; Shindo, Masami

    1996-11-01

    For expanding utilization of the Ni-Cr-W superalloy, which has been developed as one of new high temperature structural materials used in the advanced High Temperature Gas-cooled Reactors (HTGRs), in various engineering fields including the structural material for heat utilization system, the oxidation behavior of this alloy in air as one of high oxidizing environments becomes one of key factors. The oxidation tests for the industrial scale heat of Ni-Cr-W superalloy with the optimized chemical composition and five kinds of experimental Ni-Cr-W alloys with different Cr/W ratio were carried out at high temperatures in the air compared with Hastelloy XR. The conclusions were obtained as follows. (1) The oxidation resistance of the industrial scale heat of Ni-Cr-W superalloy with the optimized chemical composition was superior to that of Hastelloy XR. (2) The most excellent oxidation resistance was obtained in an alloy with 19% Cr of the industrial scale heat of Ni-Cr-W superalloy. (author)

  3. Refractory porcelain enamel passive-thermal-control coating for high-temperature superalloys

    Science.gov (United States)

    Levin, H.; Auker, B. H.; Gardos, M. N.

    1973-01-01

    Study was conducted to match thermal expansion coefficients thereby preventing enamels from cracking. Report discusses various enamel coatings that are applied to two different high-temperature superalloys. Study may be of interest to manufacturers of chemical equipment, furnaces, and metal components intended for high-temperature applications.

  4. MC Carbide Characterization in High Refractory Content Powder-Processed Ni-Based Superalloys

    Science.gov (United States)

    Antonov, Stoichko; Chen, Wei; Huo, Jiajie; Feng, Qiang; Isheim, Dieter; Seidman, David N.; Sun, Eugene; Tin, Sammy

    2018-04-01

    Carbide precipitates in Ni-based superalloys are considered to be desirable phases that can contribute to improving high-temperature properties as well as aid in microstructural refinement of the material; however, they can also serve as crack initiation sites during fatigue. To date, most of the knowledge pertaining to carbide formation has originated from assessments of cast and wrought Ni-based superalloys. As powder-processed Ni-based superalloys are becoming increasingly widespread, understanding the different mechanisms by which they form becomes increasingly important. Detailed characterization of MC carbides present in two experimental high Nb-content powder-processed Ni-based superalloys revealed that Hf additions affect the resultant carbide morphologies. This morphology difference was attributed to a higher magnitude of elastic strain energy along the interface associated with Hf being soluble in the MC carbide lattice. The composition of the MC carbides was studied through atom probe tomography and consisted of a complex carbonitride core, which was rich in Nb and with slight Hf segregation, surrounded by an Nb carbide shell. The characterization results of the segregation behavior of Hf in the MC carbides and the subsequent influence on their morphology were compared to density functional theory calculations and found to be in good agreement, suggesting that computational modeling can successfully be used to tailor carbide features.

  5. Freckle Defect Formation near the Casting Interfaces of Directionally Solidified Superalloys.

    Science.gov (United States)

    Hong, Jianping; Ma, Dexin; Wang, Jun; Wang, Fu; Sun, Baode; Dong, Anping; Li, Fei; Bührig-Polaczek, Andreas

    2016-11-16

    Freckle defects usually appear on the surface of castings and industrial ingots during the directional solidification process and most of them are located near the interface between the shell mold and superalloys. Ceramic cores create more interfaces in the directionally solidified (DS) and single crystal (SX) hollow turbine blades. In order to investigate the location of freckle occurrence in superalloys, superalloy CM247 LC was directionally solidified in an industrial-sized Bridgman furnace. Instead of ceramic cores, Alumina tubes were used inside of the casting specimens. It was found that freckles occur not only on the casting external surfaces, but also appear near the internal interfaces between the ceramic core and superalloys. Meanwhile, the size, initial position, and area of freckle were investigated in various diameters of the specimens. The initial position of the freckle chain reduces when the diameter of the rods increase. Freckle area follows a linear relationship in various diameters and the average freckle fraction is 1.1% of cross sectional area of casting specimens. The flow of liquid metal near the interfaces was stronger than that in the interdendritic region in the mushy zone, and explained why freckle tends to occur on the outer or inner surfaces of castings. This new phenomenon suggests that freckles are more likely to occur on the outer or inner surfaces of the hollow turbine blades.

  6. Freckle Defect Formation near the Casting Interfaces of Directionally Solidified Superalloys

    Directory of Open Access Journals (Sweden)

    Jianping Hong

    2016-11-01

    Full Text Available Freckle defects usually appear on the surface of castings and industrial ingots during the directional solidification process and most of them are located near the interface between the shell mold and superalloys. Ceramic cores create more interfaces in the directionally solidified (DS and single crystal (SX hollow turbine blades. In order to investigate the location of freckle occurrence in superalloys, superalloy CM247 LC was directionally solidified in an industrial-sized Bridgman furnace. Instead of ceramic cores, Alumina tubes were used inside of the casting specimens. It was found that freckles occur not only on the casting external surfaces, but also appear near the internal interfaces between the ceramic core and superalloys. Meanwhile, the size, initial position, and area of freckle were investigated in various diameters of the specimens. The initial position of the freckle chain reduces when the diameter of the rods increase. Freckle area follows a linear relationship in various diameters and the average freckle fraction is 1.1% of cross sectional area of casting specimens. The flow of liquid metal near the interfaces was stronger than that in the interdendritic region in the mushy zone, and explained why freckle tends to occur on the outer or inner surfaces of castings. This new phenomenon suggests that freckles are more likely to occur on the outer or inner surfaces of the hollow turbine blades.

  7. Erosion–corrosion behaviour of Ni-based superalloy Superni-75

    Indian Academy of Sciences (India)

    The super-heater and re-heater tubes of the boilers used in thermal power plants are ... mechanism, resulting in the tube wall thinning and premature failure. The nickel-based superalloys can be used as boiler tube materials to increase the ...

  8. MGI-oriented High-throughput Measurement of Interdiffusion Coefficient Matrices in Ni-based Superalloys

    Directory of Open Access Journals (Sweden)

    TANG Ying

    2017-01-01

    Full Text Available One of the research hotspots in the field of high-temperature alloys was to search the substitutional elements for Re in order to prepare the single-crystal Ni-based superalloys with less or even no Re addition. To find the elements with similar or even lower diffusion coefficients in comparison with that of Re was one of the effective strategies. In multicomponent alloys, the interdiffusivity matrix were used to comprehensively characterize the diffusion ability of any alloying elements. Therefore, accurate determination of the composition-dependant and temperature-dependent interdiffusivities matrices of different elements in γ and γ' phases of Ni-based superalloys was high priority. The paper briefly introduces of the status of the interdiffusivity matrices determination in Ni-based superalloys, and the methods for determining the interdiffusivities in multicomponent alloys, including the traditional Matano-Kirkaldy method and recently proposed numerical inverse method. Because the traditional Matano-Kirkaldy method is of low efficiency, the experimental reports on interdiffusivity matrices in ternary and higher order sub-systems of the Ni-based superalloys were very scarce in the literature. While the numerical inverse method newly proposed in our research group based on Fick's second law can be utilized for high-throughput measurement of accurate interdiffusivity matrices in alloys with any number of components. After that, the successful application of the numerical inverse method in the high-throughput measurement of interdiffusivity matrices in alloys is demonstrated in fcc (γ phase of the ternary Ni-Al-Ta system. Moreover, the validation of the resulting composition-dependant and temperature-dependent interdiffusivity matrices is also comprehensively made. Then, this paper summarizes the recent progress in the measurement of interdiffusivity matrices in γ and γ' phases of a series of core ternary Ni-based superalloys achieved in

  9. Microstructural and mechanical property characterization of ingot metallurgy ODS iron aluminide

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K.; Howell, C.R. [Oak Ridge National Lab., TN (United States); Hall, F.; Valykeo, J. [Hoskins Mfg. Co., Hamburg, MI (United States)

    1997-12-01

    This paper deals with a novel, lower cost method of producing a oxide dispersion strengthened (ODS) iron-aluminide alloy. A large 250-kg batch of ODS iron-aluminide alloy designated as FAS was produced by Hoskins Manufacturing Company (Hoskins) [Hamburg, Michigan] using the new process. Plate and bar stock of the ODS alloy were the two major products received. Each of the products was characterized for its microstructure, including grain size and uniformity of oxide dispersion. Tensile tests were completed from room temperature to 1100 C. Only 100-h creep tests were completed at 800 and 1000 C. The results of these tests are compared with the commercial ODS alloy designated as MA-956. An assessment of these data is used to develop future plans for additional work and identifying applications.

  10. High resolution SEM characterization of nano-precipitates in ODS steels.

    Science.gov (United States)

    Jóźwik, Iwona; Strojny-Nędza, Agata; Chmielewski, Marcin; Pietrzak, Katarzyna; Kurpaska, Łukasz; Nosewicz, Szymon

    2018-05-01

    The performance of the present-day scanning electron microscopy (SEM) extends far beyond delivering electronic images of the surface topography. Oxide dispersion strengthened (ODS) steel is on of the most promising materials for the future nuclear fusion reactor because of its good radiation resistance, and higher operation temperature up to 750°C. The microstructure of ODS should not exceed tens of nm, therefore there is a strong need in a fast and reliable technique for their characterization. In this work, the results of low-kV SEM characterization of nanoprecipitates formed in the ODS matrix are presented. Application of highly sensitive photo-diode BSE detector in SEM imaging allowed for the registration of single nm-sized precipitates in the vicinity of the ODS alloys. The composition of the precipitates has been confirmed by TEM-EDS. © 2018 Wiley Periodicals, Inc.

  11. Development of advanced P/M Ni-base superalloys for turbine disks

    Directory of Open Access Journals (Sweden)

    Garibov Genrikh S.

    2014-01-01

    Full Text Available In the process of evolution of powder metallurgy in Russia the task permanently formulated was the following: to improve strength properties of P/M superalloys without application of additional complex HIPed blanks deformation operation. On the other hand development of a turbine disk material structure to ensure an improvement in aircraft engine performance requires the use of special HIP and heat treatment conditions. To ensure maximum strength properties of disk materials it is necessary to form a structure which would have optimum size of solid solution grains, γ′-phases and carbides. Along with that heating of the material up to a temperature determined by solvus of an alloy ensures a stable and reproducible level of mechanical properties of the disks. The above-said can be illustrated by successful mastering of new complex-alloyed VVP-class superalloys with the use of powder size − 100 μm. Application of special HIP and heat treatment conditions for these superalloys to obtain the desired grain size and the strengthening γ′-phase precipitates allowed a noticeable improvement in ultimate tensile strength and yield strength up to ≥1600 MPa and ≥1200 MPa respectively. 100 hrs rupture strength at 650 ∘C and 750 ∘C was improved up to 1140 MPa and 750 MPa respectively. P/M VVP nickel-base superalloys offer higher characteristics in comparison with many superalloys designed for the same purposes. HIPed disc compacts manufactured from PREP-powder have a homogeneous micro- and macrostructure, a stable level of mechanical properties.

  12. Solid solution strengthening and diffusion in nickel- and cobalt-based superalloys

    Energy Technology Data Exchange (ETDEWEB)

    Rehman, Hamad ur

    2016-07-01

    Nickel and cobalt-based superalloys with a γ-γ{sup '} microstructure are known for their excellent creep resistance at high temperatures. Their microstructure is engineered using different alloying elements, that partition either to the fcc γ matrix or to the ordered γ{sup '} phase. In the present work the effect of alloying elements on their segregation behaviour in nickel-based superalloys, diffusion in cobalt-based superalloys and the temperature dependent solid solution strengthening in nickel-based alloys is investigated. The effect of dendritic segregation on the local mechanical properties of individual phases in the as-cast, heat treated and creep deformed state of a nickel-based superalloy is investigated. The local chemical composition is characterized using Electron Probe Micro Analysis and then correlated with the mechanical properties of individual phases using nanoindentation. Furthermore, the temperature dependant solid solution hardening contribution of Ta, W and Re towards fcc nickel is studied. The room temperature hardening is determined by a diffusion couple approach using nanoindentation and energy dispersive X-ray analysis for relating hardness to the chemical composition. The high temperature properties are determined using compression strain rate jump tests. The results show that at lower temperatures, the solute size is prevalent and the elements with the largest size difference with nickel, induce the greatest hardening consistent with a classical solid solution strengthening theory. At higher temperatures, the solutes interact with the dislocations such that the slowest diffusing solute poses maximal resistance to dislocation glide and climb. Lastly, the diffusion of different technically relevant solutes in fcc cobalt is investigated using diffusion couples. The results show that the large atoms diffuse faster in cobalt-based superalloys similar to their nickel-based counterparts.

  13. Solid solution strengthening and diffusion in nickel- and cobalt-based superalloys

    International Nuclear Information System (INIS)

    Rehman, Hamad ur

    2016-01-01

    Nickel and cobalt-based superalloys with a γ-γ ' microstructure are known for their excellent creep resistance at high temperatures. Their microstructure is engineered using different alloying elements, that partition either to the fcc γ matrix or to the ordered γ ' phase. In the present work the effect of alloying elements on their segregation behaviour in nickel-based superalloys, diffusion in cobalt-based superalloys and the temperature dependent solid solution strengthening in nickel-based alloys is investigated. The effect of dendritic segregation on the local mechanical properties of individual phases in the as-cast, heat treated and creep deformed state of a nickel-based superalloy is investigated. The local chemical composition is characterized using Electron Probe Micro Analysis and then correlated with the mechanical properties of individual phases using nanoindentation. Furthermore, the temperature dependant solid solution hardening contribution of Ta, W and Re towards fcc nickel is studied. The room temperature hardening is determined by a diffusion couple approach using nanoindentation and energy dispersive X-ray analysis for relating hardness to the chemical composition. The high temperature properties are determined using compression strain rate jump tests. The results show that at lower temperatures, the solute size is prevalent and the elements with the largest size difference with nickel, induce the greatest hardening consistent with a classical solid solution strengthening theory. At higher temperatures, the solutes interact with the dislocations such that the slowest diffusing solute poses maximal resistance to dislocation glide and climb. Lastly, the diffusion of different technically relevant solutes in fcc cobalt is investigated using diffusion couples. The results show that the large atoms diffuse faster in cobalt-based superalloys similar to their nickel-based counterparts.

  14. Commissioning and initial experimental program of the BGO-OD experiment at ELSA

    Science.gov (United States)

    Alef, S.; Bauer, P.; Bayadilov, D.; Beck, R.; Becker, M.; Bella, A.; Bielefeldt, P.; Böse, S.; Braghieri, A.; Brinkmann, K.; Cole, P.; Di Salvo, R.; Dutz, H.; Elsner, D.; Fantini, A.; Freyermuth, O.; Friedrich, S.; Frommberger, F.; Ganenko, V.; Geffers, D.; Gervino, G.; Ghio, F.; Görtz, S.; Gridnev, A.; Gutz, E.; Hammann, D.; Hannappel, J.; Hillert, W.; Ignatov, A.; Jahn, R.; Joosten, R.; Jude, T. C.; Klein, F.; Knaust, J.; Kohl, K.; Koop, K.; Krusche, B.; Lapik, A.; Levi Sandri, P.; Lopatin, I. V.; Mandaglio, G.; Messi, F.; Messi, R.; Metag, V.; Moricciani, D.; Mushkarenkov, A.; Nanova, M.; Nedorezov, V.; Novinskiy, D.; Pedroni, P.; Reitz, B.; Romaniuk, M.; Rostomyan, T.; Rudnev, N.; Schaerf, C.; Scheluchin, G.; Schmieden, H.; Stugelev, A.; Sumachev, V.; Tarakanov, V.; Vegna, V.; Walther, D.; Watts, D.; Zaunick, H.; Zimmermann, T.

    2016-11-01

    BGO-OD is a new meson photoproduction experiment at the ELSA facility of Bonn University. It aims at the investigation of non strange and strange baryon excitations, and is especially designed to be able to detect weekly bound meson-baryon type structures. The setup for the BGO-OD experiment is presented, the characteristics of the photon beam and the detector performances are shown and the initial experimental program is discussed.

  15. Chemical engineering and structural and pharmacological characterization of the α-scorpion toxin OD1.

    Science.gov (United States)

    Durek, Thomas; Vetter, Irina; Wang, Ching-I Anderson; Motin, Leonid; Knapp, Oliver; Adams, David J; Lewis, Richard J; Alewood, Paul F

    2013-01-01

    Scorpion α-toxins are invaluable pharmacological tools for studying voltage-gated sodium channels, but few structure-function studies have been undertaken due to their challenging synthesis. To address this deficiency, we report a chemical engineering strategy based upon native chemical ligation. The chemical synthesis of α-toxin OD1 was achieved by chemical ligation of three unprotected peptide segments. A high resolution X-ray structure (1.8 Å) of synthetic OD1 showed the typical βαββ α-toxin fold and revealed important conformational differences in the pharmacophore region when compared with other α-toxin structures. Pharmacological analysis of synthetic OD1 revealed potent α-toxin activity (inhibition of fast inactivation) at Nav1.7, as well as Nav1.4 and Nav1.6. In addition, OD1 also produced potent β-toxin activity at Nav1.4 and Nav1.6 (shift of channel activation in the hyperpolarizing direction), indicating that OD1 might interact at more than one site with Nav1.4 and Nav1.6. Investigation of nine OD1 mutants revealed that three residues in the reverse turn contributed significantly to selectivity, with the triple OD1 mutant (D9K, D10P, K11H) being 40-fold more selective for Nav1.7 over Nav1.6, while OD1 K11V was 5-fold more selective for Nav1.6 than Nav1.7. This switch in selectivity highlights the importance of the reverse turn for engineering α-toxins with altered selectivity at Nav subtypes.

  16. Age-hardening susceptibility of high-Cr ODS ferritic steels and SUS430 ferritic steel

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Dongsheng, E-mail: chen.dongsheng85@gmail.com [Graduate School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Kimura, Akihiko; Han, Wentuo; Je, Hwanil [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan)

    2015-10-15

    Highlights: • The role of oxide particles in α/α′ phase decomposition behavior; microstructure of phase decomposition observed by TEM. • The characteristics of ductility loss caused by age-hardening. • Correlation of phase decomposition and age-hardening explained by dispersion strengthened models. • Age-hardening susceptibility of ODS steels and SUS430 steel. - Abstract: The effect of aging on high-Cr ferritic steels was investigated with focusing on the role of oxide particles in α/α′ phase decomposition behavior. 12Cr-oxide dispersion strengthened (ODS) steel, 15Cr-ODS steel and commercial SUS430 steel were isothermally aged at 475 °C for up to 10,000 h. Thermal aging caused a larger hardening in SUS430 than 15Cr-ODS, while 12Cr-ODS showed almost no hardening. A characteristic of the ODS steels is that the hardening was not accompanied by the significant loss of ductility that was observed in SUS430 steel. After aging for 2000 h, SUS430 steel shows a larger ductile–brittle transition temperature (DBTT) shift than 15Cr-ODS steel, which suggests that the age-hardening susceptibility is lower in 15Cr-ODS steel than in conventional SUS430 steel. Thermal aging leaded to a large number of Cr-rich α′ precipitates, which were confirmed by transmission electron microscopy (TEM). Correlation of age-hardening and phase decomposition was interpreted by Orowan type strengthening model. Results indicate that oxide particles cannot only suppress ductility loss, but also may influence α/α′ phase decomposition kinetics.

  17. [Study on the correlation between PMI and OD changes in rat's plasma].

    Science.gov (United States)

    Li, Wei; Ke, Yong; He, Guang-she; Xu, Yong-cheng; Wang, Zhen-yuan

    2008-12-01

    We chose the UV-Vis spectrophotometry as a new way to investigate the postmortem interval (PMI). One hundred fifty Sprague-Dawley female rats (weight 260 g +/- 10 g, from Xi'an Jiaotong University Animal Center) were chosen and sacrificed by cervical dislocation. The bodies were kept in a controlled environmental chamber set at (20 +/- 2) degrees C. The plasma was harvested in course of 0 to 24 hours after death. The optical density (OD) at different wavelengths was measured with an UV-Vis spectrophotometer (type-UV250). It was shown that the OD changes of plasma at 577, 416 and 275 nm in 24 hours were dramatically related to PMI, and the R-indexes were 0.969, 0.97 and 0.898. The regression formulae of these indexes were worked out taking OD as independent variable, and PMI as variable. The quadratic equations were: PMI = 231.2270D(plasma at wavelength of 577 nm) - 501.160D(plasma at wavelength of 577 nm)2 - 3.0809(R2 = 0.945), PMI = 31.7426OD(plasma at wavelength of 416 nm) - 9.1847OD(plasma at wavelength of 416 nm)2 - 31837(R2 = 0.94), and PMI = 95.2388OD(plasma at wavelength of 275 nm) - 39.343OD(plama at wavelength of 275 nm)2 - 32.408(R2 = 0.795). It was concluded that the OD changes of rat's plasma are good and potential markers for the estimation of PMI and should be very useful in forensic practice.

  18. Analysis of sorption into single ODS-silica gel microparticles in acetonitrile-water.

    Science.gov (United States)

    Nakatani, Kiyoharu; Kakizaki, Hiroshi

    2003-08-01

    Intraparticle mass transfer processes of Phenol Blue (PB) in single octadecylsilyl (ODS)-silica gel microparticles in acetonitrile-water were analyzed by microcapillary manipulation and microabsorption methods. An absorption maximum of PB, the sorption isotherm parameters, and the sorption rate in the microparticle system were highly dependent on the percentage of acetonitrile in solution. The results are discussed in terms of the microscopic polarity surrounding PB in the ODS phase and the relationship between the isotherm parameters and the sorption rate.

  19. Investigation of the relationships between mechanical properties and microstructure in a Fe-9%Cr ODS steel

    OpenAIRE

    Hary Benjamin; Guilbert Thomas; Wident Pierre; Baudin Thierry; Logé Roland; de Carlan Yann

    2016-01-01

    Ferritic-martensitic Oxide Dispersion Strengthened (ODS) steels are potential materials for fuel pin cladding in Sodium Fast Reactor (SFR) and their optimisation is essential for future industrial applications. In this paper, a feasibility study concerning the generation of tensile specimens using a quenching dilatometer is presented. The ODS steel investigated contains 9%Cr and exhibits a phase transformation between ferrite and austenite around 870 °C. The purpose was to generate different ...

  20. Effects of electrical discharge surface modification of superalloy Haynes 230 with aluminum and molybdenum on oxidation behavior

    International Nuclear Information System (INIS)

    Bai, C.-Y.

    2007-01-01

    The effects of the electrical discharge alloying (EDA) process on improving the high temperature oxidation resistance of the Ni-based superalloy Haynes 230 have been investigated. The 85 at.% Al and 15 at.% Mo composite electrode provided the surface alloying materials. An Al-rich layer is produced on the surface of the EDA specimen alloyed with positive electrode polarity, whereas, many discontinuous piled layers are attached to the surface of the EDA superalloy when negative electrode polarity is selected. The oxidation resistance of the specimen alloyed with positive electrode polarity is better than that of the unalloyed superalloy, and the effective temperature of oxidation resistance of the alloyed layer can be achieved to 1100 o C. Conversely, the oxidation resistance of the other EDA specimen alloyed with negative electrode polarity is even worse than that of the unalloyed superalloy

  1. Dense sheet Z-pinches

    International Nuclear Information System (INIS)

    Tetsu, Miyamoto

    1999-01-01

    The steady state and quasi-steady processes of infinite- and finite-width sheet z-pinches are studied. The relations corresponding to the Bennett relation and Pease-Braginskii current of cylindrical fiber z-pinches depend on a geometrical factor in the sheet z-pinches. The finite-width sheet z-pinch is approximated by a segment of infinite-width sheet z-pinch, if it is wide enough, and corresponds to a number of (width/thickness) times fiber z-pinch plasmas of the diameter that equals the sheet thickness. If the sheet current equals this number times the fiber current, the plasma created in the sheet z-pinches is as dense as in the fiber z-pinches. The total energy of plasma and magnetic field per unit mass is approximately equal in both pinches. Quasi-static transient processes are different in several aspects from the fiber z-pinch. No radiation collapse occurs in the sheet z-pinch. The stability is improved in the sheet z-pinches. The fusion criterions and the experimental arrangements to produce the sheet z-pinches are also discussed. (author)

  2. Relationship between microstructure and mechanical properties in ODS materials for nuclear application

    International Nuclear Information System (INIS)

    De Carlan, Y.

    2013-01-01

    Oxide Dispersion Strengthened ferritic/martensitic alloys are developed as prospective cladding materials for future Sodium-Cooled-Fast-Reactors (GEN IV) [1]. These advanced alloys present a good resistance to irradiation and a high creep rupture strength due to a reinforcement by the homogeneous dispersion of hard nano-sized particles (such as Y 2 O 3 or YTiO). ODS alloys are elaborated by powder metallurgy, consolidated by hot extrusion and manufactured into cladding tube using the Pilger cold-rolling process [2, 3]. ODS alloys present usually low ductility and high hardness. The aim of this talk is to present the specificity of the metallurgy of ODS materials in relationship with the main mechanical properties (tensile and creep properties, toughness, transition temperature). Two types of alloys will be presented: Fe-9Cr martensitic ODS and Fe-14Cr ferritic ODS alloys. Mechanical properties of the materials depend on the metallurgical state (fine grains, recrystallized, martensitic) and very different behaviors are observed as a function of final microstructure. For example, for a Fe-9Cr ODS alloy, tempered martensite lets obtaining material with high strength whereas softened ferrite see figure 1 [4] tolerates high deformation levels. (authors)

  3. Development of Oxide Dispersion Strengthened (ODS) Ferritic Steel Through Powder Forging

    Science.gov (United States)

    Kumar, Deepak; Prakash, Ujjwal; Dabhade, Vikram V.; Laha, K.; Sakthivel, T.

    2017-04-01

    Oxide dispersion strengthened (ODS) ferritic steels are candidates for cladding tubes in fast breeder nuclear reactors. In this study, an 18%Cr ODS ferritic steel was prepared through powder forging route. Elemental powders with a nominal composition of Fe-18Cr-2 W-0.2Ti (composition in wt.%) with 0 and 0.35% yttria were prepared by mechanical alloying in a Simoloyer attritor under argon atmosphere. The alloyed powders were heated in a mild steel can to 1473 K under flowing hydrogen atmosphere. The can was then hot forged. Steps of sealing, degassing and evacuation are eliminated by using powder forging. Heating ODS powder in hydrogen atmosphere ensures good bonding between alloy powders. A dense ODS alloy with an attractive combination of strength and ductility was obtained after re-forging. On testing at 973 K, a loss in ductility was observed in yttria-containing alloy. The strength and ductility increased with increase in strain rate at 973 K. Reasons for this are discussed. The ODS alloy exhibited a recrystallized microstructure which is difficult to achieve by extrusion. No prior particle boundaries were observed after forging. The forged compacts exhibited isotropic mechanical properties. It is suggested that powder forging may offer several advantages over the traditional extrusion/HIP routes for fabrication of ODS alloys.

  4. Influence of Zr addition on the microstructures and mechanical properties of 14Cr ODS steels

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Liye [State Key Lab of Hydraulic Engineering Simulation and Safety, Tianjin key Lab of Composite and Functional Materials, Tianjin University, Tianjin 300072 (China); Yu, Liming, E-mail: lmyu@tju.edu.cn [State Key Lab of Hydraulic Engineering Simulation and Safety, Tianjin key Lab of Composite and Functional Materials, Tianjin University, Tianjin 300072 (China); Liu, Yongchang; Liu, Chenxi; Li, Huijun [State Key Lab of Hydraulic Engineering Simulation and Safety, Tianjin key Lab of Composite and Functional Materials, Tianjin University, Tianjin 300072 (China); Wu, Jiefeng [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2017-05-17

    Oxide dispersion strengthened (ODS) steel is one of the most promising candidate structural materials for the high-temperature nuclear reactor application. In this study, two compositions of ODS steels (14Cr-ODS and 14Cr-Zr-ODS) were prepared to investigate the influence of Zr addition on the microstructures and mechanical properties of ODS steels. The microstructures, including dispersion morphology and crystal structures of oxide particles, particle-matrix interface coherency and particle-dislocation interactions, were characterized using TEM, HRTEM, and SEM, and the mechanical properties at room and high temperatures were measured using uniaxial tensile tests. Results show that Zr addition leads to the formation of finer precipitated particles, which was identified as rhombohedral Y{sub 4}Zr{sub 3}O{sub 12}, with denser dispersion in the matrix. The calculation results reveal that the lattice misfit, δ, at the interface between particle and matrix increases as the particle size increases. In addition, the strength and elongation of ODS steels are improved with Zr addition due to the stronger interface bonding force between fine particles and matrix as well as the larger pinning effect of small particles to dislocation movements.

  5. Evaluation of oxide dispersion strengthened (ODS) molybdenum and molybdenum-rhenium alloys

    International Nuclear Information System (INIS)

    Mueller, A.J.; Bianco, R.; Buckman, R.W. Jr.

    1999-01-01

    Oxide dispersion strengthened (ODS) molybdenum alloys being developed for high temperature applications possess excellent high temperature strength and creep resistance. In addition they exhibit a ductile-to-brittle transition temperature (DBIT) in the worked and stress-relieved condition under longitudinal tensile load well below room temperature. However, in the recrystallized condition, the DBTT maybe near or above room temperature, depending on the volume fraction of oxide dispersion and the amount of prior work. Dilute rhenium additions (7 and 14 wt.%) to ODS molybdenum were evaluated to determine their effect on low temperature ductility. The addition of 7 wt.% rhenium to the ODS molybdenum did not significantly enhance the mechanical properties. However, the addition of 14 wt.% rhenium to the ODS molybdenum resulted in a DBTT well below room temperature in both the stress-relieved and recrystallized condition. Additionally, the tensile strength of ODS Mo-14Re is greater than the base ODS molybdenum at 1,000 to 1,250 C

  6. Atom probe characterization of yttria particles in ODS Eurofer steel

    International Nuclear Information System (INIS)

    Aleev, A.A.; Zaluzhny, A.G.; Nikitin, A.A.; Rogozhkin, S.V.; Iskandarov, N.A.; Vladimirov, P.; Moeslang, A.; Lindau, R.; Klimenkov, M.

    2009-01-01

    Oxide dispersion strengthened steels exhibit higher temperature and radiation resistance than conventionally produced ferritic/martensitic steels. Such behaviour, as believed, is mainly caused by presence of highly dispersed and extremely stable oxide particles with sizes of few nanometers. It was shown that the most promising oxide additive was yttria (Y 2 O 3 ) and as mechanical parameters were strongly depended on size and number density of formed peculiarities it is required to reduce their dimensions to few nanometers and drastically increase their number. At present, considerable effort is focused on investigation of behaviour and properties of such particles. Recent studies of Eurofer ODS steel (9%-CrWVTa) by SANS and PoAS revealed the presence of high number density structural peculiarities with size approximately one nanometer. At the same time, previous studies by TEM identified only high number of small (5-10 nm) Y 2 O 3 particles. So, the purpose of this work was to look into this material by means of tomographic atom probe and find out the chemistry and origin of peculiarities with sizes less than 5 nm. These investigations revealed fine (∼ 2 nm) particles that were enriched not only in yttrium and oxygen but also in vanadium and nitrogen. Concentration of vanadium in them is approximately at the same level as yttrium. Moreover, some particles were found to be enriched in only three or even two elements mentioned above. However, total concentration of chemical elements in these particles is considerably less than that of iron. Estimated number density for detected particles is (1 / 5) x 10 23 m -3 . (author)

  7. Perforation of metal sheets

    DEFF Research Database (Denmark)

    Steenstrup, Jens Erik

    simulation is focused on the sheet deformation. However, the effect on the tool and press is included. The process model is based on the upper bound analysis in order to predict the force progress and hole characteristics etc. Parameter analyses are divided into two groups, simulation and experimental tests......The main purposes of this project are:1. Development of a dynamic model for the piercing and performation process2. Analyses of the main parameters3. Establishing demands for process improvements4. Expansion of the existing parameter limitsThe literature survey describes the process influence...

  8. Cyclic Oxidation of High Mo, Reduced Density Superalloys

    Directory of Open Access Journals (Sweden)

    James L. Smialek

    2015-11-01

    Full Text Available Cyclic oxidation was characterized as part of a statistically designed, 12-alloy compositional study of 2nd generation single crystal superalloys as part of a broader study to co-optimize density, creep strength, and cyclic oxidation. The primary modification was a replacement of 5 wt. % W by 7% or 12% Mo for density reductions of 2%–7%. Compositions at two levels of Mo, Cr, Co, and Re were produced, along with a midpoint composition. Initially, polycrystalline vacuum induction samples were screened in 1100 °C cyclic furnace tests using 1 h cycles for 200 h. The behavior was primarily delimited by Cr content, producing final weight changes of −40 mg/cm2 to −10 mg/cm2 for 0% Cr alloys and −2 mg/cm2 to +1 mg/cm2 for 5% Cr alloys. Accordingly, a multiple linear regression fit yielded an equation showing a strong positive Cr effect and lesser negative effects of Co and Mo. The results for 5% Cr alloys compare well to −1 mg/cm2, and +0.5 mg/cm2 for Rene′ N4 and Rene′ N5 (or Rene′ N6, respectively. Scale phases commonly identified were Al2O3, NiAl2O4, NiTa2O6, and NiO, with (Ni,CoMoO4 found only on the least resistant alloys having 0% Cr and 12% Mo. Scale microstructures were complex and reflected variations in the regional spallation history. Large faceted NiO grains and fine NiTa2O6 particles distributed along NiAl2O4 grain boundaries were typical distinctive features. NiMoO4 formation, decomposition, and volatility occurred for a few high Mo compositions. A creep, density, phase stability, and oxidation balanced 5% Cr, 10% Co, 7% Mo, and 3% Re alloy was selected to be taken forward for more extensive evaluations in single crystal form.

  9. Microstructural aspects of Ni-based superalloy 693

    International Nuclear Information System (INIS)

    Dutta, R.S.; Sengupta, P.; Tewari, R.; Kain, V.; Dey, G.K.; Sharma, A.K.; Raj, K.

    2009-01-01

    Alloy 693 is an austenitic, precipitation-hardenable Ni-based superalloy. It is a promising material for high temperature fuel cell, petrochemical processing industry, high temperature waste and biomass incinerators and as thermal processing equipment, burner nozzles, melter pot material and in other areas. Microstructure plays quite often a major role in regulating the properties of the materials. Keeping this in view, optical microscope, scanning electron microscope (SEM) and transmission electron microscope (TEM) were employed to characterize the microstructure of Alloy 693. Microanalyses of the phases were performed by using electron probe microanalysis (EPMA) and TEM along with energy dispersive spectroscopy (EDS). The alloy in as-received condition under an optic microscope and SEM revealed the presence of predominantly finer intergranular precipitates and randomly distributed coarser precipitates of various morphologies. EPMA of spherical-shaped coarse precipitate indicated that the major constituent of this precipitate has been chromium. Besides this, niobium-rich irregular-shaped coarse precipitate was also detected. The finer grain boundary precipitates in the alloy appeared to be of Cr-carbide. TEM examination on as-received alloy indicated very uniform distribution of a large volume fraction of fine precipitates in the austenite matrix. Selected area diffraction (SAD) pattern, dark-field TEM and detailed analyses confirmed that these fine precipitates have been ordered Ni 3 Al type phase. TEM investigation also revealed the presence of coarse particles of various morphologies. Analyses of such particles indicated this phase as M 6 C type. EDS analyses indicated that the major constituents of these coarse particles have been Cr and Ni. Minor elements like Fe, Al and Nb were also detected in all the particles with some variation of their contents from particle to particle. TEM investigation on annealed (1373 K/30 minutes, WQ) specimen of Alloy 693

  10. Experiments on sheet metal shearing

    OpenAIRE

    Gustafsson, Emil

    2013-01-01

    Within the sheet metal industry, different shear cutting technologies are commonly used in several processing steps, e.g. in cut to length lines, slitting lines, end cropping etc. Shearing has speed and cost advantages over competing cutting methods like laser and plasma cutting, but involves large forces on the equipment and large strains in the sheet material.Numerical models to predict forces and sheared edge geometry for different sheet metal grades and different shear parameter set-ups a...

  11. Sol-gel open tubular ODS columns with reversed electroosmotic flow for capillary electrochromatography.

    Science.gov (United States)

    Hayes, J D; Malik, A

    2001-03-01

    Sol-gel chemistry was successfully used for the fabrication of open tubular columns with surface-bonded octadecylsilane (ODS) stationary-phase coating for capillary electrochromatography (OT-CEC). Following column preparations, a series of experiments were performed to investigate the performance of the sol-gel coated ODS columns in OT-CEC. The incorporation of N-octadecyldimethyl[3-(trimethoxysilyl)propyl]ammonium chloride as one of the sol-gel precursors played an important role in the electrochromatographic performance of the prepared columns. This chemical reagent possesses a chromatographically favorable, bonded ODS moiety, in conjunction with three methoxy groups allowing for sol-gel reactivity. In addition, a positively charged nitrogen atom is present in the molecular structure of this reagent and provides a positively charged capillary surface responsible for the reversed electroosmotic flow (EOF) in the columns during CEC operation. Comparative studies involving the EOF within such sol-gel ODS coated and uncoated capillaries were performed using acetonitrile and methanol as the organic modifiers in the mobile phase. The use of a deactivating reagent, phenyldimethylsilane, in the sol-gel solution was evaluated. Efficiency values of over 400,000 theoretical plates per meter were achieved in CEC on a 64 cm x 25 microm i.d. sol-gel ODS open tubular column. Test mixtures of polycyclic aromatic hydrocarbons, benzene derivatives, and aromatic aldehydes and ketones were used to evaluate the CEC performances of both nondeactivated and deactivated open tubular sol-gel columns. The effects of mobile-phase organic modifier contents and pH on EOF in such columns were evaluated. The prepared sol-gel ODS columns are characterized by switchable electroosmotic flow. A pH value of approximately 8.5 was found correspond to the isoelectric point for the prepared sol-gel ODS coatings.

  12. HPLC separation of triacylglycerol positional isomers on a polymeric ODS column.

    Science.gov (United States)

    Kuroda, Ikuma; Nagai, Toshiharu; Mizobe, Hoyo; Yoshimura, Nobuhito; Gotoh, Naohiro; Wada, Shun

    2008-07-01

    A polymeric ODS column was applied to the resolution of triacylglycerol positional isomers (TAG-PI), i.e. 1,3-dioleoyl-2-palmitoyl-glycerol (OPO) and 1,2-dioleoyl-3-palmitoyl-rac-glycerol (OOP), with a recycle HPLC system. To investigate the ODS column species and the column temperatures for the resolution of a TAG-PI pair, a mixture of OPO and OOP was subjected to an HPLC system equipped with a non-endcapped polymeric, endcapped monomeric, endcapped intermediate, or non-endcapped monomeric ODS column at three different column temperatures (40, 25, or 10 degrees C). Only the non-endcapped polymeric ODS column achieved the separation of OPO and OOP, and the lowest column temperature (10 degrees C) showed the best resolution for them. The other pair of TAG-PI, a mixture of 1,3-dipalmitoyl-2-oleoyl-glycerol (POP) and 1,2-dipalmitoyl-3-oleoyl-rac-glycerol (PPO) was also subjected to the system equipped with a non-endcapped polymeric or monomeric ODS column at five different column temperatures (40, 32, 25, 17, and 10 degrees C). Thus, POP and PPO were also separated on only the non-endcapped polymeric ODS column at 25 degrees C. However, no clear peak appeared at 10 degrees C. These results would indicate that the polymeric ODS stationary phase has an ability to recognize the structural differences between TAG-PI pairs. Also, the column temperature is a very important factor for separating the TAG-PI pair, and the optimal temperature would relate to the solubility of TAG-PI in the mobile phase. Furthermore, the recycle HPLC system provided measurements for the separation and analysis of TAG-PI pairs.

  13. O(d, - Collapse/inflation in Colliding Superstring Waves

    Science.gov (United States)

    Bozza, V.; Veneziano, G.

    2002-12-01

    The present formulation of pre-big bang cosmology relies on the principle of asymptotic past triviality (APT)1 , i.e. on the assumption that, in its initial state, the Universe was in a low-curvature, small-coupling regime and was thus adequately described in terms of the low-energy, tree-level effective action of string theory. The early universe can thus be visualized as a chaotic superposition of massless waves, seen as excitations over a trivial Minkowski background. The superposition of these perturbations can eventually lead to the gravitational collapse of the interaction region. Measuring distances in string units, such a collapse can become an inflationary, dilaton-driven, expansion. According to the scenario depicted in Ref. 1, the collapse/inflation of sufficiently large regions could then evolve in a universe resembling our own. An explicit example of this phenomenon was given by Feinstein, Kunze & Vázquez-Mozo2 who studied a particular exact solution of the field equations describing the collision of two four-dimensional gravi-dilatonic plane waves. In our work3, including from the start the Kalb-Ramond Bμν 2-form in an arbitrary number D of space-time dimensions we recover their result in a more general O(d, d)-invariant formulation, allowing a full investigation of a wider class of solutions. The two plane waves are taken to travel in opposite directions along the same axis, so that, assuming plane symmetry, all fields are functions of the time coordinate and the common direction of propagation z. The problem is thus endowed with d = D - 2 abelian isometries, the action being invariant for translations along the transverse directions. In this situation, it is possible to write the action in terms of the restriction of the metric on the non-trivial coordinates (t, z), the shifted dilaton and a 2d × 2d matrix M built by combining the remaining components of the metric and the antisymmetric field...

  14. Gründerzeit – Od skandalu do stylu

    Directory of Open Access Journals (Sweden)

    Jacek K. Knothe

    2017-12-01

    Full Text Available Przyjmuje się, iż architektura ‘okresu założycieli’ – ‘Grűnderzeit’ występowała w Niemczech w latach 1870-1920, to jest dłużej niż do zakończenia I wojny światowej stanowiącej swoistą cezurę XX wieku. Na terenie Polski, w miarę rozprzestrzeniania się przychodzącego z Europy postępu technicznego, styl Grűnderzeit następował pod koniec XIX wieku z niewielkim tylko opóźnieniem w stosunku do Niemiec, a wraz z nim jeszcze 12 stylów okresu historyzmu. Budynki z okresu Grűnderzeit, powszechnie obecne w centrach polskich miast pomimo zniszczeń spowodowanych II wojną, stanowią zwykle obiekty najstarsze i choćby z tego powodu uznawane są za estetyczny kanon historycznej zabudowy mieszkaniowej. Zamiarem autora jest przywrócenie do literatury polskiej terminu Grűnderzeit jako bardziej precyzyjnie określającego styl niż termin ‘historyzm’, używany do opisania praktycznie każdej formy architektonicznej z okresu poprzedzającego modernizm. Autorowi chodzi też o spowodowanie w polskiej literaturze dekonstrukcji terminu ‘historyzm’ i wyodrębnienie z niego terminu Grűnderzeit, ponadto o rozprawienie się z funkcjonującymi na temat stylu Grűnderzeit uprzedzeniami oraz o wykazanie związków i wpływu tego stylu na architekturę tkanki miejskiej większości polskich miast, nie tylko tych położonych na zachód od Wisły. Bezrefleksyjność lub też pogląd, iż architektura z przełomu XIX i XX wieku na terenie Polski nie miała korzeni w XIX wiecznej architekturze Europy, a jeśli nawet miała, to na pewno nie były one niemieckie, w erze globalizmu która właśnie wtedy się rozpoczynała, nie wytrzymuje próby.

  15. Growth mechanisms of oxide scales on ODS alloys in the temperature range 1000-1100deg C

    International Nuclear Information System (INIS)

    Quadakkers, W.J.

    1990-01-01

    After a short overview of the production, microstructure and mechanical properties of nickel- and iron-based oxide dispersion strengthened (ODS) alloys, the oxidation properties of this class of materials is extensively discussed. The excellent oxidation resistance of ODS alloys is illustrated by comparing their behaviour with conventional chromia and alumina forming wrought alloys of the same base composition. ODS alloys exhibit improved scale adherence, decreased oxide growth rates, enhanced selective oxidation and decreased oxide grain size compared to corresponding non-ODS alloys. It is shown, that these experimental observations can be explained by a change in oxide growth mechanism. The presence of the oxide dispersion reduces cation diffusion in the scale, causing the oxides on the ODS alloys to grow mainly by oxygen grain boundary transport. As oxide grain size increases with time, the oxide growth kinetics obey a sub-parabolic time dependence especially in the case of the alumina forming iron-based ODS alloy. (orig.) [de

  16. Soft Costs Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-05-01

    This fact sheet is an overview of the systems integration subprogram at the U.S. Department of Energy SunShot Initiative. Soft costs can vary significantly as a result of a fragmented energy marketplace. In the U.S., there are 18,000 jurisdictions and 3,000 utilities with different rules and regulations for how to go solar. The same solar equipment may vary widely in its final installation price due to process and market variations across jurisdictions, creating barriers to rapid industry growth. SunShot supports the development of innovative solutions that enable communities to build their local economies and establish clean energy initiatives that meet their needs, while at the same time creating sustainable solar market conditions.

  17. Photovoltaics Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-02-01

    This fact sheet is an overview of the Photovoltaics (PV) subprogram at the U.S. Department of Energy SunShot Initiative. The U.S. Department of Energy (DOE)’s Solar Energy Technologies Office works with industry, academia, national laboratories, and other government agencies to advance solar PV, which is the direct conversion of sunlight into electricity by a semiconductor, in support of the goals of the SunShot Initiative. SunShot supports research and development to aggressively advance PV technology by improving efficiency and reliability and lowering manufacturing costs. SunShot’s PV portfolio spans work from early-stage solar cell research through technology commercialization, including work on materials, processes, and device structure and characterization techniques.

  18. Systems Integration Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-06-01

    This fact sheet is an overview of the Systems Integration subprogram at the U.S. Department of Energy SunShot Initiative. The Systems Integration subprogram enables the widespread deployment of safe, reliable, and cost-effective solar energy technologies by addressing the associated technical and non-technical challenges. These include timely and cost-effective interconnection procedures, optimal system planning, accurate prediction of solar resources, monitoring and control of solar power, maintaining grid reliability and stability, and many more. To address the challenges associated with interconnecting and integrating hundreds of gigawatts of solar power onto the electricity grid, the Systems Integration program funds research, development, and demonstration projects in four broad, interrelated focus areas: grid performance and reliability, dispatchability, power electronics, and communications.

  19. Hyperspectral light sheet microscopy

    Science.gov (United States)

    Jahr, Wiebke; Schmid, Benjamin; Schmied, Christopher; Fahrbach, Florian O.; Huisken, Jan

    2015-09-01

    To study the development and interactions of cells and tissues, multiple fluorescent markers need to be imaged efficiently in a single living organism. Instead of acquiring individual colours sequentially with filters, we created a platform based on line-scanning light sheet microscopy to record the entire spectrum for each pixel in a three-dimensional volume. We evaluated data sets with varying spectral sampling and determined the optimal channel width to be around 5 nm. With the help of these data sets, we show that our setup outperforms filter-based approaches with regard to image quality and discrimination of fluorophores. By spectral unmixing we resolved overlapping fluorophores with up to nanometre resolution and removed autofluorescence in zebrafish and fruit fly embryos.

  20. Settlement during vibratory sheet piling

    NARCIS (Netherlands)

    Meijers, P.

    2007-01-01

    During vibratory sheet piling quite often the soil near the sheet pile wall will settle. In many cases this is not a problem. For situations with houses, pipelines, roads or railroads at relative short distance these settlements may not be acceptable. The purpose of the research described in this

  1. Development of Austenitic ODS Strengthened Alloys for Very High Temperature Applications

    Energy Technology Data Exchange (ETDEWEB)

    Stubbins, James [Univ. of Illinois, Urbana-Champaign, IL (United States); Heuser, Brent [Univ. of Illinois, Urbana-Champaign, IL (United States); Robertson, Ian [Kyushu Univ. (Japan); Sehitoglu, Huseyin [Univ. of Illinois, Urbana-Champaign, IL (United States); Sofronis, Petros [Kyushu Univ. (Japan); Gewirth, Andrew [Kyushu Univ. (Japan)

    2015-04-22

    This “Blue Sky” project was directed at exploring the opportunities that would be gained by developing Oxide Dispersion Strengthened (ODS) alloys based on the Fe-Cr-Ni austenitic alloy system. A great deal of research effort has been directed toward ferritic and ferritic/martensitic ODS alloys which has resulted in reasonable advances in alloy properties. Similar gains should be possible with austenitic alloy which would also take advantage of other superior properties of that alloy system. The research effort was aimed at the developing an in-depth understanding of the microstructural-level strengthening effects of ODS particles in austentic alloys. This was accomplished on a variety of alloy compositions with the main focus on 304SS and 316SS compositions. A further goal was to develop an understanding other the role of ODS particles on crack propagation and creep performance. Since these later two properties require bulk alloy material which was not available, this work was carried out on promising austentic alloy systems which could later be enhanced with ODS strengthening. The research relied on a large variety of micro-analytical techniques, many of which were available through various scientific user facilities. Access to these facilities throughout the course of this work was instrumental in gathering complimentary data from various analysis techniques to form a well-rounded picture of the processes which control austenitic ODS alloy performance. Micromechanical testing of the austenitic ODS alloys confirmed their highly superior mechanical properties at elevated temperature from the enhanced strengthening effects. The study analyzed the microstructural mechanisms that provide this enhanced high temperature performance. The findings confirm that the smallest size ODS particles provide the most potent strengthening component. Larger particles and other thermally- driven precipitate structures were less effective contributors and, in some cases, limited

  2. Effect of Mechanical Alloying Atmospheres and Oxygen Concentration on Mechanical Properties of ODS Ferritic Steels

    International Nuclear Information System (INIS)

    Noh, Sanghoon; Choi, Byoungkwon; Han, Changhee; Kim, Kibaik; Kang, Sukhoon; Chun, Youngbum; Kim, Taekyu

    2013-01-01

    Finely dispersed nano-oxide particles with a high number density in the homogeneous grain matrix are essential to achieve superior mechanical properties at high temperatures, and these unique microstructures can be obtained through the mechanical alloying (MA) and hot consolidation process. The microstructure and mechanical property of ODS steel significantly depends on its powder property and the purity after the MA process. These contents should be carefully controlled to improve the mechanical property at elevated temperature. In particular, appropriate the control of oxygen concentration improves the mechanical property of ODS steel at high temperature. An effective method is to control the mechanical alloying atmosphere by high purity inert gas. In the present study, the effects of mechanical alloying atmospheres and oxygen concentration on the mechanical property of ODS steel were investigated. ODS ferritic alloys were fabricated in various atmospheres, and the HIP process was used to investigate the effects of MA atmospheres and oxygen concentration on the microstructure and mechanical property. ODS ferritic alloys milled in an Ar-H 2 mixture, and He is effective to reduce the excess oxygen concentration. The YH 2 addition made an extremely reduced oxygen concentration by the internal oxygen reduction reaction and resulted in a homogeneous microstructure and superior creep strength

  3. HRTEM Study of the Role of Nanoparticles in ODS Ferritic Steel

    Energy Technology Data Exchange (ETDEWEB)

    Hsiung, L; Tumey, S; Fluss, M; Serruys, Y; Willaime, F

    2011-08-30

    Structures of nanoparticles and their role in dual-ion irradiated Fe-16Cr-4.5Al-0.3Ti-2W-0.37Y{sub 2}O{sub 3} (K3) ODS ferritic steel produced by mechanical alloying (MA) were studied using high-resolution transmission electron microscopy (HRTEM) techniques. The observation of Y{sub 4}Al{sub 2}O{sub 9} complex-oxide nanoparticles in the ODS steel imply that decomposition of Y{sub 2}O{sub 3} in association with internal oxidation of Al occurred during mechanical alloying. HRTEM observations of crystalline and partially crystalline nanoparticles larger than {approx}2 nm and amorphous cluster-domains smaller than {approx}2 nm provide an insight into the formation mechanism of nanoparticles/clusters in MA/ODS steels, which we believe involves solid-state amorphization and re-crystallization. The role of nanoparticles/clusters in suppressing radiation-induced swelling is revealed through TEM examinations of cavity distributions in (Fe + He) dual-ion irradiated K3-ODS steel. HRTEM observations of helium-filled cavities (helium bubbles) preferably trapped at nanoparticle/clusters in dual-ion irradiated K3-ODS are presented.

  4. Influences of process parameters and microstructure on the fracture mechanisms of ODS steels

    International Nuclear Information System (INIS)

    Rouffié, A.L.; Wident, P.; Ziolek, L.; Delabrouille, F.; Tanguy, B.; Crépin, J.; Pineau, A.; Garat, V.; Fournier, B.

    2013-01-01

    The present work investigates the impact response of three ODS steels containing 9%Cr and 14%Cr. These steels were produced by hot extrusion in the shapes of a rod and a plate. The 9%Cr ODS steel has a quasi-isotropic microstructure and is given as a reference material. In comparison, the 14%Cr ODS steel has a strong morphological and crystallographic texture given by the process route. The impact behaviour is anisotropic and the fracture energies are higher when the material is tested in the longitudinal direction compared to the transverse direction. Moreover, the 14%Cr ODS steel has a better impact behaviour when it is extruded in the shape of a rod rather than in the shape of a plate. This work focuses on the fracture mechanisms involved in the ductile to brittle transition regime and in the brittle regime of these materials. In the case of the 14%Cr ODS steel, the cleavage facets observed at very low temperature are much larger than the actual size of the grains. Packets of grains with less than 15° of internal misorientation were defined as effective grains for cleavage. In the transition range, the texture enhances intergranular delamination on the 14%Cr rod material. The occurrence of delamination consumes a lot of energy and tends to enhance scattering in impact energies

  5. Influences of process parameters and microstructure on the fracture mechanisms of ODS steels

    Energy Technology Data Exchange (ETDEWEB)

    Rouffié, A.L., E-mail: anne-laure.rouffie@cea.fr [CEA, DEN, DANS, DMN, SRMA, Bât 453, F-91191 Gif-sur-Yvette (France); Wident, P.; Ziolek, L. [CEA, DEN, DANS, DMN, SRMA, Bât 453, F-91191 Gif-sur-Yvette (France); Delabrouille, F. [EDF – EDF R and D, Département MMC groupe Métallurgie, 77818 Moret sur Loing (France); Tanguy, B. [CEA, DEN, DANS, DMN, SEMI, Bât 625, F-91191 Gif-sur-Yvette (France); Crépin, J.; Pineau, A. [Mines ParisTech, Centre des Matériaux PM Fourt, UMR CNRS 7633, BP 87, 91003 Evry (France); Garat, V. [AREVA NP, 10 rue J. Récamier, 69006 Lyon (France); Fournier, B. [Manoir Industries, Metallurgy Dept., 12 rue des Ardennes, BP 8401 Pîtres, 27108 Val de Reuil Cedex (France)

    2013-02-15

    The present work investigates the impact response of three ODS steels containing 9%Cr and 14%Cr. These steels were produced by hot extrusion in the shapes of a rod and a plate. The 9%Cr ODS steel has a quasi-isotropic microstructure and is given as a reference material. In comparison, the 14%Cr ODS steel has a strong morphological and crystallographic texture given by the process route. The impact behaviour is anisotropic and the fracture energies are higher when the material is tested in the longitudinal direction compared to the transverse direction. Moreover, the 14%Cr ODS steel has a better impact behaviour when it is extruded in the shape of a rod rather than in the shape of a plate. This work focuses on the fracture mechanisms involved in the ductile to brittle transition regime and in the brittle regime of these materials. In the case of the 14%Cr ODS steel, the cleavage facets observed at very low temperature are much larger than the actual size of the grains. Packets of grains with less than 15° of internal misorientation were defined as effective grains for cleavage. In the transition range, the texture enhances intergranular delamination on the 14%Cr rod material. The occurrence of delamination consumes a lot of energy and tends to enhance scattering in impact energies.

  6. Long-range activation of Sox9 in Odd Sex (Ods) mice.

    Science.gov (United States)

    Qin, Yangjun; Kong, Ling-kun; Poirier, Christophe; Truong, Cavatina; Overbeek, Paul A; Bishop, Colin E

    2004-06-15

    The Odd Sex mouse mutation arose in a transgenic line of mice carrying a tyrosinase minigene driven by the dopachrome tautomerase (Dct) promoter region. The minigene integrated 0.98 Mb upstream of Sox9 and was accompanied by a deletion of 134 kb. This mutation causes female to male sex reversal in XX Ods/+ mice, and a characteristic eye phenotype of microphthalmia with cataracts in all mice carrying the transgene. Ods causes sex reversal in the absence of Sry by upregulating Sox9 expression and maintaining a male pattern of Sox9 expression in XX Ods/+ embryonic gonads. This expression, which begins at E11.5, triggers downstream events leading to the formation of a testis. We report here that the 134 kb deletion, in itself, is insufficient to cause sex reversal. We demonstrate that in Ods, the Dct promoter is capable of acting over a distance of 1 Mb to induce inappropriate expression of Sox9 in the retinal pigmented epithelium of the eye, causing the observed microphthalmia. In addition, it induces Sox9 expression in the melanocytes where it causes pigmentation defects. We propose that Ods sex reversal is due to the Dct promoter element interacting with gonad-specific enhancer elements to produce the observed male pattern expression of Sox9 in the embryonic gonads.

  7. Role of enterocele in the obstructed defecation syndrome (ODS): a new radiological point of view.

    Science.gov (United States)

    Morandi, C; Martellucci, J; Talento, P; Carriero, A

    2010-08-01

    The aim of this study was to understand the role of enterocele in the pathogenesis of the obstructed defecation syndrome (ODS) a new defecographic classification based on function. A total of 597 patients (551 women, 46 men) who underwent cinedefecography between November 2001 and November 2005 were studied. A total of 567 (95%) underwent cinedefecography as they had symptoms of ODS. Enterocele was classified into three types. Enterocele was found in 127 (23%) female and one (2.2%) male patients. Thirty-eight (6.9%) patients had type A, 38(6.9%) type B, and 27(4.9%) type C enterocele. A total of 24 patients (4.35%) had sigmoidocele. In patients with type C enterocele, the finding of a radiological pattern of ODS was higher (26/27) than that in the other groups (A + B + Sigmoidocele) (23/100) (P ODS and usually presents as an isolated condition. Type B is less frequently associated with ODS and is more frequently accompanied by other pathological conditions.

  8. Comparison of a polymeric pseudostationary phase in EKC with ODS stationary phase in RP-HPLC.

    Science.gov (United States)

    Ni, Xinjiong; Zhang, Min; Xing, Xiaoping; Cao, Yuhua; Cao, Guangqun

    2018-01-01

    Poly(stearyl methacrylate-co-methacrylic acid) (P(SMA-co-MAA)) was induced as pseudostationary phase (PSP) in electrokinetic chromatography (EKC). The n-octadecyl groups in SMA were the same as that in octadecylsilane (ODS) C18 column. Thus, the present work focused on the comparison of selectivity between polymeric PSP and ODS stationary phase (SP), and the effect of organic modifiers on the selectivity of polymeric PSP and ODS SP. 1-butanol could directly interacted with PSP as a Class I modifier, and improved both of the methylene selectivity and polar group selectivity. When the analysis times were similar, the polymeric PSP exhibited better methylene selectivity and polar group selectivity. Although the hydrophobic groups were similar, the substituted benzenes elution order was different between polymeric PSP and ODS SP. Linear solvation energy relationships (LSER) model analysis found that polymeric PSP and ODS SP exhibited two same key factors in selectivity: hydrophobic interaction and hydrogen bonding acidity. But polymeric PSP exhibited relatively strong n- and π-electrons interaction to the analytes. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Creep constitutive equation of dual phase 9Cr-ODS steel

    International Nuclear Information System (INIS)

    Sakasegawa, Hideo; Ukai, Shigeharu; Tamura, Manabu; Ohtsuka, Satoshi; Tanigawa, Hiroyasu; Ogiwara, Hiroyuki; Kohyama, Akira; Fujiwara, Masayuki

    2008-01-01

    9Cr-ODS (oxide dispersion strengthened) steels developed by JAEA (Japan Atomic Energy Agency) have superior creep properties compared with conventional heat resistant steels. The ODS steels can enormously contribute to practical applications of fast breeder reactors and more attractive fusion reactors. Key issues are developments of material processing procedures for mass production and creep life prediction methods in present R and D. In this study, formulation of creep constitutive equation was performed against the backdrop. The 9Cr-ODS steel displaying an excellent creep property is a dual phase steel. The ODS steel is strengthened by the δ ferrite which has a finer dispersion of oxide particles and shows a higher hardness than the α' martensite. The δ ferrite functions as a reinforcement in the dual phase 9Cr-ODS steel. Its creep behavior is very unique and cannot be interpreted by conventional theories of heat resistant steels. Alternative qualitative model of creep mechanism was formulated at the start of this study using the results of microstructural observations. Based on the alternative creep mechanism model, a novel creep constitutive equation was formulated using the exponential type creep equation extended by a law of mixture

  10. Hardness distribution and effect of irradiation in FSW-ODS ferritic steels

    International Nuclear Information System (INIS)

    Noh, Sanghoon; Kasada, Ryuta; Kimura, Akihiko; Nagasaka, Takuya; Sokolov, M.A.; Yamamoto, T.

    2014-01-01

    Oxide dispersion strengthened ferritic steels (ODS-FS) have been considered as one of the most promising structural materials for advanced nuclear systems such as fusion reactors and next generation fission reactors, because of its excellent elevated temperature strength, corrosion and radiation resistance. Especially, irradiation resistance is a critical issue for the high performance of ODS-FS. In this study, effects of the irradiation on hardness properties of friction stri processed (FSP) ODS-FS were investigated. FSP technique was employed on ODS-FS. A plate specimen was cut out from the cross section and irradiated to 1.2 dpa at 573K in the High Flux Isotope Reactor (HFIR). To investigate the effect of neutron irradiation on processed area, the hardness distributions were evaluated on the cross section. Hardness of FSP ODS-FS was various with each microstructure after irradiation to 1.2 dpa at 573K. The increase of Vickers hardness was significant in the stirred zone and heat affected zone. Base material exhibited the lowest hardening about 38HV. Since nano-oxide particles in stirred zone showed identical mean diameter and number density, it is considered that hardening differences between stirred zone and base material is due to differences in initial dislocation density. (author)

  11. Cyclic Oxidation and Hot Corrosion of NiCrY-Coated Disk Superalloys

    Science.gov (United States)

    Gabb, Timothy P.; Miller, Robert A.; Sudbrack, Chantal K.; Draper, Susan L.; Nesbitt, James A.; Rogers, Richard B.; Telesman, Ignacy; Ngo, Vanda; Healy, Jonathan

    2016-01-01

    Powder metallurgy disk superalloys have been designed for higher engine operating temperatures through improvement of their strength and creep resistance. Yet, increasing disk application temperatures to 704 degrees Centigrade and higher could enhance oxidation and activate hot corrosion in harmful environments. Protective coatings could be necessary to mitigate such attack. Cylindrical coated specimens of disk superalloys LSHR and ME3 were subjected to thermal cycling to produce cyclic oxidation in air at a maximum temperature of 760 degrees Centigrade. The effects of substrate roughness and coating thickness on coating integrity after cyclic oxidation were considered. Selected coated samples that had cyclic oxidation were then subjected to accelerated hot corrosion tests. This cyclic oxidation did not impair the coating's resistance to subsequent hot corrosion pitting attack.

  12. Cyclic Oxidation and Hot Corrosion of NiCrY-Coated Disk Superalloy

    Science.gov (United States)

    Gabb, Tim; Miller, R. A.; Sudbrack, C. K.; Draper, S. L.; Nesbitt, J.; Telesman, J.; Ngo, V.; Healy, J.

    2015-01-01

    Powder metallurgy disk superalloys have been designed for higher engine operating temperatures through improvement of their strength and creep resistance. Yet, increasing disk application temperatures to 704 C and higher could enhance oxidation and activate hot corrosion in harmful environments. Protective coatings could be necessary to mitigate such attack. Cylindrical coated specimens of disk superalloys LSHR and ME3 were subjected to thermal cycling to produce cyclic oxidation in air at a maximum temperature of 760 C. The effects of substrate roughness and coating thickness on coating integrity after cyclic oxidation were considered. Selected coated samples that had cyclic oxidation were then subjected to accelerated hot corrosion tests. The effects of this cyclic oxidation on resistance to subsequent hot corrosion attack were examined.

  13. Liquation Cracking in the Heat-Affected Zone of IN738 Superalloy Weld

    Directory of Open Access Journals (Sweden)

    Kai-Cheng Chen

    2018-05-01

    Full Text Available The main scope of this study investigated the occurrence of liquation cracking in the heat-affected zone (HAZ of IN738 superalloy weld, IN738 is widely used in gas turbine blades in land-based power plants. Microstructural examinations showed considerable amounts of γ’ uniformly precipitated in the γ matrix. Electron probe microanalysis (EPMA maps showed the γ-γ’ colonies were rich in Al and Ti, but lean in other alloy elements. Moreover, the metal carbides (MC, fine borides (M3B2 and M5B3, η-Ni3Ti, σ (Cr-Co and lamellar Ni7Zr2 intermetallic compounds could be found at the interdendritic boundaries. The fracture morphologies and the corresponding EPMA maps confirmed that the liquation cracking in the HAZ of the IN738 superalloy weld resulted from the presence of complex microconstituents at the interdendritic boundaries.

  14. Metallurgical joining of engine parts. Inertia welding of nickel superalloy HP compressor disks

    International Nuclear Information System (INIS)

    Ferte, J.P.

    1993-01-01

    The main part of this paper describes upside metallurgical and mechanical work done at SNECMA, on inertia welding of powder metallurgy nickel base superalloys ASTROLOY and N18, allowing appliance of this process to engine parts : Inertia welding of superalloys leads to deap microstructural changes in the H.A.Z. which have been, as well as upset, correlated to process parameters, weld geometry and base material microstructure; a full mechanical testing of welds shown properties equivalent to base material ones up to 650 C except for fatigue crack growth behavior under specific conditions (T>600 C-hold time at maximum load) which is drastically reduced for in weld plane propagation. A significant improvement of this later property has been done through post-welding heat treatment and optimization of welding parameters. Last part of this paper summarize the main teachings gained, on the complete welding procedure, from welding of scale one parts. (orig.)

  15. On the microstructural origin of primary creep in nickel-base superalloys

    International Nuclear Information System (INIS)

    Heilmaier, M.; Reppich, B.

    1997-01-01

    The nature of primary creep in nickel-base superalloys is strongly correlated to the different hardening species present in the material. In fine-grained single-phase material the classical assumption of a homogeneous dislocation distribution enables the prediction of the transition from normal via sigmoidal to inverse primary creep with decreasing applied stress σ. In coarse-grained material the back stress σ b of hard subgrain boundaries evolving during plastic deformation must be additionally taken into account. Second-phase particles influence creep in a 2-fold manner via reducing the effective stress σ eff , namely directly by the stress σ p * for particle overcoming, and indirectly by increasing the dislocation density ρ. The proposed approach accounts for the observed pronounced normal primary creep in particle-strengthened superalloys. (orig.)

  16. Intermediate Co/Ni-base model superalloys — Thermophysical properties, creep and oxidation

    International Nuclear Information System (INIS)

    Zenk, Christopher H.; Neumeier, Steffen; Engl, Nicole M.; Fries, Suzana G.; Dolotko, Oleksandr; Weiser, Martin; Virtanen, Sannakaisa; Göken, Mathias

    2016-01-01

    The mechanical properties of γ′-strengthened Co–Ni–Al–W–Cr model superalloys extending from pure Ni-base to pure Co-base superalloys have been assessed. Differential scanning calorimetry measurements and thermodynamic calculations match well and show that the γ′ solvus temperature decreases with increasing Co-content. The γ/γ′ lattice misfit is negative on the Ni- and positive on the Co-rich side. High Ni-contents decelerate the oxidation kinetics up to a factor of 15. The creep strength of the Ni-base alloy increases by an order of magnitude with additions of Co before it deteriorates strongly upon higher additions despite an increasing γ′ volume fraction.

  17. Extension of an anisotropic creep model to general high temperature deformation of a single crystal superalloy

    International Nuclear Information System (INIS)

    Pan, L.M.; Ghosh, R.N.; McLean, M.

    1993-01-01

    A physics based model has been developed that accounts for the principal features of anisotropic creep deformation of single crystal superalloys. The present paper extends this model to simulate other types of high temperature deformation under strain controlled test conditions, such as stress relaxation and tension tests at constant strain rate in single crystals subject to axial loading along an arbitrary crystal direction. The approach is applied to the SRR99 single crystal superalloy where a model parameter database is available, determined via analysis of a database of constant stress creep curves. A software package has been generated to simulate the deformation behaviour under complex stress-strain conditions taking into account anisotropic elasticity. (orig.)

  18. Development of superalloys for 1700 C ultra-efficient gas turbines

    Energy Technology Data Exchange (ETDEWEB)

    Harada, Hiroshi [National Institute for Materials Science, Tsukuba, Ibaraki (Japan). High Temperature Materials Center

    2010-07-01

    Mitigation of global warming is one of the most outstanding issues for the humankind. The Japanese government announced that it will reduce its greenhouse gas emissions by 25% from the 1990 level by 2020 as a medium-term goal. One of the promising approaches to achieving this is to improve the efficiency of thermal power plants emitting one-third of total CO{sub 2} gas in Japan. The key to improving the thermal efficiency is high temperature materials with excellent temperature capabilities allowing higher inlet gas temperatures. In this context, new single crystal superalloys for turbine blades and vanes, new coatings and turbine disk superalloys have been successfully developed for various gas turbine applications, typically 1700 C ultra-efficient gas turbines for next generation combine cycle power plants. (orig.)

  19. Atomic force microscopy imaging to measure precipitate volume fraction in nickel-based superalloys

    International Nuclear Information System (INIS)

    Bourhettar, A.; Troyon, M.; Hazotte, A.

    1995-01-01

    In nickel-based superalloys, quantitative analysis of scanning electron microscopy images fails in providing accurate microstructural data, whereas more efficient techniques are very time-consuming. As an alternative approach, the authors propose to perform quantitative analysis of atomic force microscopy images of polished/etched surfaces (quantitative microprofilometry). This permits the measurement of microstructural parameters and the depth of etching, which is the main source of measurement bias. Thus, nonbiased estimations can be obtained by extrapolation of the measurements up to zero etching depth. In this article, the authors used this approach to estimate the volume fraction of γ' precipitates in a nickel-based superalloy single crystal. Atomic force microscopy images of samples etched for different times show definition, homogeneity, and contrast high enough to perform image analysis. The result after extrapolation is in very good agreement with volume fraction values available from published reports

  20. Computer Aided Design of Ni-Based Single Crystal Superalloy for Industrial Gas Turbine Blades

    Science.gov (United States)

    Wei, Xianping; Gong, Xiufang; Yang, Gongxian; Wang, Haiwei; Li, Haisong; Chen, Xueda; Gao, Zhenhuan; Xu, Yongfeng; Yang, Ming

    The influence of molybdenum, tungsten and cobalt on stress-rupture properties of single crystal superalloy PWA1483 has been investigated using the simulated calculation of JMatPro software which ha s been widely used to develop single crystal superalloy, and the effect of alloying element on the stability of strengthening phase has been revealed by using the Thermo-Calc software. Those properties calculation results showed that the increasing of alloy content could facilitate the precipitation of TCP phases and increase the lattice misfit between γ and γ' phase, and the effect of molybdenum, tantalum was the strongest and that of cobalt was the weakest. Then the chemical composition was optimized, and the selected compositions showed excellent microstructure stability and stress-rupture properties by the confirmation of d-electrons concept and software calculation.

  1. Microstructure of the Nickel-Base Superalloy CMSX-4 Fabricated by Selective Electron Beam Melting

    Science.gov (United States)

    Ramsperger, Markus; Singer, Robert F.; Körner, Carolin

    2016-03-01

    Powder bed-based additive manufacturing (AM) processes are characterized by very high-temperature gradients and solidification rates. These conditions lead to microstructures orders of magnitude smaller than in conventional casting processes. Especially in the field of high performance alloys, like nickel-base superalloys, this opens new opportunities for homogenization and alloy development. Nevertheless, the high susceptibility to cracking of precipitation-hardenable superalloys is a challenge for AM. In this study, electron beam-based AM is used to fabricate samples from gas-atomized pre-alloyed CMSX-4 powder. The influence of the processing strategy on crack formation is investigated. The samples are characterized by optical and SEM microscopy and analyzed by microprobe analysis. Differential scanning calorimetry is used to demonstrate the effect of the fine microstructure on characteristic temperatures. In addition, in situ heat treatment effects are investigated.

  2. On post-weld heat treatment cracking in tig welded superalloy ATI 718Plus

    Science.gov (United States)

    Asala, G.; Ojo, O. A.

    The susceptibility of heat affected zone (HAZ) to cracking in Tungsten Inert Gas (TIG) welded Allvac 718Plus superalloy during post-weld heat treatment (PWHT) was studied. Contrary to the previously reported case of low heat input electron beam welded Allvac 718Plus, where HAZ cracking occurred during PWHT, the TIG welded alloy is crack-free after PWHT, notwithstanding the presence of similar micro-constituents that caused cracking in the low input weld. Accordingly, the formation of brittle HAZ intergranular micro-constituents may not be a sufficient factor to determine cracking propensity, the extent of heat input during welding may be another major factor that influences HAZ cracking during PWHT of the aerospace superalloy Allvac 718Plus.

  3. Heat affected zone liquation cracking in electron beam welded third generation nickel base superalloys

    International Nuclear Information System (INIS)

    Ojo, O.A.; Wang, Y.L.; Chaturvedi, M.C.

    2008-01-01

    The weldability of directionally solidified nickel base superalloy TMS-75 and TMS-75+C was investigated by autogenous bead-on-plate electron beam welding. The analysis of microsegregation that occurred during solidification of the as-cast alloys indicated that while W and Re segregated into the γ dendrites of both the alloys, Ta, Hf and C were rejected into the interdendritic liquid in the TMS-75+C. Heat affected zone intergranular liquation cracking was observed in both the materials and was observed to be closely associated with liquated γ-γ' eutectic microconstituent. The TMS-75+C alloy, however, exhibited a reduced extent of HAZ cracking compared to TMS-75. Suppression of terminal solidification reaction involving non-invariant γ-γ' eutectic transformation due to modification of primary solidification path by carbon addition is suggested to be an important factor contributing to reduced susceptibility of TMS-75+C alloy to HAZ liquation cracking relative to the TMS-75 superalloy

  4. Effect of cobalt on microstructural parameters and mechanical properties of Ni-base single crystal superalloys

    International Nuclear Information System (INIS)

    Suzuki, Takanobu; Imai, Hachiro; Yokokawa, Tadaharu; Kobayashi, Toshiharu; Koizumi, Yutaka; Harada, Hiroshi

    2007-01-01

    The alloying effect of Cobalt (Co) to microstructural parameters and mechanical properties, such as partitioning ratios of alloying elements and creep strength, of Re-bearing Ni-base single crystal superalloys have been investigated. The second generation single crystal superalloys, TMS-82+, Ni-7.8Co-4.9Cr-1.9Mo-8.7W-5.3Al-6.0Ta-2.4Re-0.1Hf, in mass% (8Co) was compared to a Co-free (0Co) and 15 mass% Co (15Co) alloy which had the same chemical composition as TMS-82+ except that Co was changed. It was shown that the partitioning ratios of alloying elements trend to k(=X γ /X' γ )=1, as the content of Co was increased. Furthermore, it was found that there was suitable content of Co for the creep strength under various temperature-stress conditions. (author)

  5. STUDY OF THE MECHANICAL PROPERTIES OF INCONEL 718 SUPERALLOY AFTER HOT TENSILE TESTS

    Directory of Open Access Journals (Sweden)

    Tarcila Sugahara

    2014-10-01

    Full Text Available This research work investigated some important mechanical properties of Inconel 718 superalloy using hot tensile tests like conventional yield strength to 0.2% strain (σe , ultimate strength (σr , and specific elongation (εu . Samples were strained to failure at temperatures of 600°C, 650°C, 700°C, 750°C, 800°C and 850°C and strain rate of 0.5 mm/min (2 × 10–4 s–1 according to ASTM E-8. The results showed higher values σe of yield strength at 700°C, this anomalous behavior can be attributed to the presence of hardening precipitates as observed in the TTT diagram of superalloy Inconel 718. Examination of the sample’s surfaces tensile fracture showed that with increasing temperature test the actuating mechanism changes from intergranular fracture to coalescence of the microcavities.

  6. Phase Transformations in Nickel base Superalloy Inconel 718 during Cyclic Loading at High Temperature

    Directory of Open Access Journals (Sweden)

    Michal Jambor

    2017-06-01

    Full Text Available Nickel base superalloys are hi-tech materials intended for high temperature applications. This property owns a complex microstructure formed by matrix of Ni and variety of precipitates. The type, form and the amount of these phases significantly affect the resulting properties of these alloys. At sufficiently long exposure to high temperatures, the transformation phase can occur, which can lead to degradation of properties of these alloys. A cyclic plastic deformation can accelerate these changes, and they could occur at significantly lower temperatures or in shorter time of exposure. The aim of this study is to describe phase transformation, which can occur by a cyclic plastic deformation at high temperatures in nickel base superalloy Inconel 718.

  7. Grain Boundary Engineering the Mechanical Properties of Allvac 718Plus(Trademark) Superalloy

    Science.gov (United States)

    Gabb, Timothy P.; Telesman, Jack; Garg, Anita; Lin, Peter; Provenzano, virgil; Heard, Robert; Miller, Herbert M.

    2010-01-01

    Grain Boundary Engineering can enhance the population of structurally-ordered "low S" Coincidence Site Lattice (CSL) grain boundaries in the microstructure. In some alloys, these "special" grain boundaries have been reported to improve overall resistance to corrosion, oxidation, and creep resistance. Such improvements could be quite beneficial for superalloys, especially in conditions which encourage damage and cracking at grain boundaries. Therefore, the effects of GBE processing on high-temperature mechanical properties of the cast and wrought superalloy Allvac 718Plus (Allvac ATI) were screened. Bar sections were subjected to varied GBE processing, and then consistently heat treated, machined, and tested at 650 C. Creep, tensile stress relaxation, and dwell fatigue crack growth tests were performed. The influences of GBE processing on microstructure, mechanical properties, and associated failure modes are discussed.

  8. The Effectiveness of a NiCrY-Coating on a Powder Metallurgy Disk Superalloy

    Science.gov (United States)

    Gabb, Timothy P.; Miller, Robert A.; Nesbitt, James A.; Draper, Susan L.; Rogers, Richard B.; Telesman, Jack

    2018-01-01

    Protective ductile coatings could be necessary to mitigate oxidation and corrosion attack on superalloy disks in some turbine engine applications. However, the effects of coatings on fatigue life of the disk during service are an important concern. The objective of this study was to investigate how such a coating could perform after varied post-coating processing. Cylindrical gage fatigue specimens of powder metallurgy-processed disk superalloy LSHR were coated with a NiCrY coating, shot peened, preparation treated, exposed, and then subjected to fatigue at high temperature. The effects of varied shot peening, preparation treatment, and exposures on fatigue life with and without the coating were compared. Each of these variables and several of their interactions significantly influenced fatigue life.

  9. Plasma dynamics in current sheets

    International Nuclear Information System (INIS)

    Bogdanov, S.Yu.; Drejden, G.V.; Kirij, N.P.; AN SSSR, Leningrad

    1992-01-01

    Plasma dynamics in successive stages of current sheet evolution is investigated on the base of analysis of time-spatial variations of electron density and electrodynamic force fields. Current sheet formation is realized in a two-dimensional magnetic field with zero line under the action of relatively small initial disturbances (linear regimes). It is established that in the limits of the formed sheet is concentrated dense (N e ∼= 10 16 cm -3 ) (T i ≥ 100 eV, bar-Z i ≥ 2) hot pressure of which is balanced by the magnetic action of electrodynamic forces is carried out both plasma compression in the sheet limits and the acceleration along the sheet surface from a middle to narrow side edges

  10. Isotope effects in the photofragmentation of symmetric molecules: The branching ratio of OD/OH in water

    DEFF Research Database (Denmark)

    Henriksen, Niels Engholm; Møller, Klaus Braagaard; Engel, Volker

    2005-01-01

    With HOD initially in its vibrational ground state, we present a new detailed interpretation of the OD/OH branching ratio (similar to 3) in the photoinduced process D+OH H+OD, in the first absorption band. Using semiclassical arguments, we show that the branching ratio has little to do...... with the initial distribution of configurations, but the initial momentum distribution plays a key role in determination of the branching ratio. The formation of D+OH arises from initial situations where OD is stretching, and it stretches faster than OH, whereas all other motions lead to H+OD. This picture...

  11. Cyclic plastic response of nickel-based superalloy at room and at elevated temperatures

    Czech Academy of Sciences Publication Activity Database

    Polák, Jaroslav; Petrenec, Martin; Chlupová, Alice; Tobiáš, Jiří; Petráš, Roman

    2015-01-01

    Roč. 57, č. 2 (2015), s. 119-125 ISSN 0025-5300 R&D Projects: GA ČR(CZ) GA13-23652S; GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : cyclic plasticity * elevat ed temperature * superalloys * hysteresis loop * statistical theory Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 0.266, year: 2015

  12. Computational and Experimental Design of Fe-Based Superalloys for Elevated-Temperature Applications

    Energy Technology Data Exchange (ETDEWEB)

    Liaw, Peter K. [Univ. of Tennessee, Knoxville, TN (United States); Fine, Morris E. [Northwestern Univ., Evanston, IL (United States); Ghosh, Gautam [Northwestern Univ., Evanston, IL (United States); Asta, Mark D. [Univ. of California, Berkeley, CA (United States); Liu, Chain T. [Auburn Univ., AL (United States); Sun, Zhiqian [Univ. of Tennessee, Knoxville, TN (United States); Huang, Shenyan [Univ. of Tennessee, Knoxville, TN (United States); Teng, Zhenke [Univ. of Tennessee, Knoxville, TN (United States); Wang, Gongyao [Univ. of Tennessee, Knoxville, TN (United States)

    2012-04-13

    Analogous to nickel-based superalloys, Fe-based superalloys, which are strengthened by coherent B2- type precipitates are proposed for elevated-temperature applications. During the period of this project, a series of ferritic superalloys have been designed and fabricated by methods of vacuum-arc melting and vacuum-induction melting. Nano-scale precipitates were characterized by atom-probe tomography, ultrasmall- angle X-ray scattering, and transmission-electron microscopy. A duplex distribution of precipitates was found. It seems that ferritic superalloys are susceptible to brittle fracture. Systematic endeavors have been devoted to understanding and resolving the problem. Factors, such as hot rolling, precipitate volume fractions, alloy compositions, precipitate sizes and inter-particle spacings, and hyperfine cooling precipitates, have been investigated. In order to understand the underlying relationship between the microstructure and creep behavior of ferric alloys at elevated temperatures, in-situ neutron studies have been carried out. Based on the current result, it seems that the major role of β' with a 16%-volume fraction in strengthening ferritic alloys is not load sharing but interactions with dislocations. The oxidation behavior of one ferritic alloy, FBB8 (Fe-6.5Al-10Ni-10Cr-3.4Mo-0.25Zr-0.005B, weight percent), was studied in dry air. It is found that it possesses superior oxidation resistance at 1,023 and 1,123 K, compared with other creep-resistant ferritic steels [T91 (modified 9Cr-1Mo, weight percent) and P92 (9Cr-1.8W-0.5Mo, weight percent)]. At the same time, the calculation of the interfacial energies between the -iron and B2-type intermetallics (CoAl, FeAl, and NiAl) has been conducted.

  13. Interdiffusion between Ni-based superalloy and MCrAlY coating

    DEFF Research Database (Denmark)

    Dahl, Kristian Vinter; Hald, John; Horsewell, Andy

    2006-01-01

    Interdiffusion at the interface between a Co-36.5Ni-17.5Cr-8Al-0.5Y, MCrAlY coating and the underlying IN738 superalloy was studied in a large matrix of specimens isothermally heat treated for up to 12,000 hours at temperatures 875oC, 925oC or 950oC. Modelled results using the finite difference...

  14. Rapid solidification and dynamic compaction of Ni-base superalloy powders

    Science.gov (United States)

    Field, R. D.; Hales, S. J.; Powers, W. O.; Fraser, H. L.

    1984-01-01

    A Ni-base superalloy containing 13Al-9Mo-2Ta (in at. percent) has been characterized in both the rapidly solidified condition and after dynamic compaction. Dynamically compacted specimens were examined in the as-compacted condition and observations related to current theories of interparticle bonding. In addition, the recrystallization behavior of the compacted material at relatively low temperature (about 0.5-0.75 Tm) was investigated.

  15. Crystallographic, microstructure and mechanical characteristics of dynamically processed IN718 superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, A.D., E-mail: ads.hpu@gmail.com [Department of Physics, Himachal Pradesh University, Shimla 171005 (India); Sharma, A.K. [Terminal Ballistics Research Laboratory, Chandigarh 160030 (India); Thakur, N. [Department of Physics, Himachal Pradesh University, Shimla 171005 (India)

    2014-06-01

    Highlights: • Measurement of detonation velocity and compaction of powder are achieved together. • A plastic explosive detonation results into dense compacts without grain-growth. • We have studied crystallographic, micromechanical and microstructural features. • The results show no segregation within the compacts. • Density (98%), microhardness (470 ± 3)H{sub v}, microstrain (0.3%), UTS (806 MPa) are obtained. - Abstract: Dynamic consolidation of IN718 superalloy powder without grain-growth and negligible density gradient is accomplished through explosively generated shock wave loading. The compaction of powder and measurement of detonation velocity are achieved successfully in a single-shot experiment by employing instrumented detonics. A plastic explosive having a detonation velocity of the order of 7.1 km/s in a direct proximity with superalloy powder is used for the consolidation process. The compacted specimens are examined for structural, microstructure and mechanical characteristics. X-ray diffraction (XRD) study suggests intact crystalline structure of the compacts. A small micro-strain (0.26%) is observed by using Williamson–Hall method. Wavelength dispersive spectroscopy indicates no segregation within the shock processed superalloy compacted specimens. The monoliths investigated for fractography by using field emission scanning electron microscopy (FE-SEM) show original dendritic structure accompanied by re-solidified molten regions across the interparticle boundaries. Depth-sensing indentations (at 1.96 N) on compacted specimens show excellent micro-hardness of the order of (470 ± 3)H{sub v}. Tensile and compressive strengths of the superalloy monolith are observed to be 806 and 822 MPa, respectively.

  16. On γ and γ' phases composition in IN-100 superalloy after high-temperature exposure

    International Nuclear Information System (INIS)

    Matteazzi, P.; Principi, G.; Ramous, E.

    1981-01-01

    The chemistry and volume fraction of UPSILON' phase in IN-100 superalloy after high-temperature exposure in furnace and in service have been examined. Increasing the time of exposure aluminium plus titanium content remains nearly constant and very close to 25 at.%; the little decrease of nickel together with the increase of iron and molybdenum suggest that the last two elements are preferentially occupying Ni-type sites, according to the pair potential model of UPSILON'. (orig.)

  17. Discussion of "Investigation of Oxide Bifilms in Investment Cast Superalloy IN100 Parts I and II"*

    Science.gov (United States)

    Campbell, John

    2017-10-01

    Fuchs and Kaplan carried out experiments in an attempt to ascertain whether oxide bifilms were present in a vacuum-cast Ni-base superalloy but concluded negatively. Although this author challenged their interpretation of their findings, both parties had overlooked the presence in the alloy of boron which is now known to inhibit bifilm formation. However, even though boron can help significantly, improved filling system designs remain important if other damaging entrainment defects are to be avoided.

  18. Analysis of microstructure in electro-spark deposited IN718 superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Anisimov, E.; Khan, A.K.; Ojo, O.A., E-mail: olanrewaju.ojo@umanitoba.ca

    2016-09-15

    The microstructure of electro-spark deposited (ESD) superalloy IN718 was studied by the use of scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) techniques. In converse to general assumption, the extremely high cooling rate involved in the ESD process did not produce partitionless solidification that is devoid of second phase microconstituents in the material, nano-sized Laves phase and MC carbide particles were observed within the deposited layer. Notwithstanding the several thermal cycles involved in the process, the extremely low heat input of the process produced a deposited region that is free of the main strengthening phase of the alloy, γ″ phase precipitates, which is in contrast to what have been reported on laser deposition. Nevertheless, application of the standard full heat treatment of the alloy resulted in extensive formation of the γ″ phase precipitates and δ phase precipitates, the most stable secondary phase of the alloy, with nearly, if not complete, dissolution of the Laves phase particles. Furthermore, the XPS analysis done in the study revealed the formation of nano-oxides within the deposited layer, which increased the microhardness of the superalloy in the as-deposited condition and inhibited its grain growth during post-process heat treatment. The microstructure analysis done in this work is crucial to the understanding of properties of the superalloy processed by the ESD technique. - Highlights: •Electron microscopy analyses of electro-spark deposited IN 718 superalloy were performed. •Nano-sized secondary phase particles were observed within the deposited layer. •The study shows that the ESD did not produce partitionless solidification of the alloy.

  19. CYCLIC STRAIN LOCALIZATION IN CAST NICKEL BASED SUPERALLOY INCONEL 792-5A AT ROOM TEMPERATURE

    Czech Academy of Sciences Publication Activity Database

    Petrenec, Martin; Man, Jiří; Obrtlík, Karel; Polák, Jaroslav

    308/2005, č. 86 (2005), s. 269-274 ISSN 1429-6055. [Metody oceny struktury oraz wlasności materialów i wyrobów. Ustroń-Jaszowiec, 07.12.2005-09.12.2005] Institutional research plan: CEZ:AV0Z20410507 Keywords : low cycle fatigue * superalloy * cyclic strain localization Subject RIV: JL - Materials Fatigue, Friction Mechanics

  20. Misorientation related microstructure at the grain boundary in a nickel-based single crystal superalloy

    International Nuclear Information System (INIS)

    Huang, Ming; Zhuo, Longchao; Liu, Zhanli; Lu, Xiaogang; Shi, Zhenxue; Li, Jiarong; Zhu, Jing

    2015-01-01

    The mechanical properties of nickel-based single crystal superalloys deteriorate with increasing misorientation, thus the finished product rate of the casting of single crystal turbine airfoils may be reduced due to the formation of grain boundaries especially when the misorientation angle exceeds to some extent. To this day, evolution of the microstructures at the grain boundaries with misorientation and the relationship between the microstructures and the mechanical properties are still unclear. In this work a detailed characterization of the misorientation related microstructure at the grain boundary in DD6 single crystal superalloy has been carried out using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques; the elemental distribution at the grain boundaries has been analyzed by energy dispersive (EDS) X-ray mapping; and the effect of precipitation of μ phases at the grain boundary on the mechanical property has been evaluated by finite element calculation. It is shown that the proportion of γ phase at the grain boundaries decreases, while the proportion of γ′ phase at the grain boundaries increases with increasing misorientation; the μ phase is precipitated at the grain boundaries when the misorientation angle exceeds about 10° and thus it could lead to a dramatic deterioration of the mechanical properties, as well as that the enrichment of Re and W gradually disappears as the misorientation angle increases. All these factors may result in the degradation of the mechanical properties at the grain boundaries as the misorientation increases. Furthermore, the finite element calculation confirms that precipitation of μ phases at the grain boundary is responsible for the significant deterioration of the mechanical properties when the misorientation exceeds about 10°. This work provides a physical imaging of the microstructure for understanding the relationship between the mechanical properties and the misorientation

  1. Behaviour and damage of a superalloy prepared by hot isostatic compression

    International Nuclear Information System (INIS)

    Dubiez-Le-Goff, Sophie

    2003-01-01

    This work deals with the behavior and damage of Udimet 720 superalloy prepared by hot isostatic compression. This alloy is considered for manufacturing turbine disks of high temperature reactors (HTR). The material choice for HTR turbine disk depends on the following criteria: a good creep resistance until 700 C, a good behaviour under an helium impure atmosphere, a possible implementation under a disk of 1.5 m diameter. (author) [fr

  2. The influence of high temperature on the microstructure properties of Ni-based superalloy

    Czech Academy of Sciences Publication Activity Database

    Luptáková, Natália; Král, Petr; Dymáček, Petr

    2014-01-01

    Roč. 14, č. 4 (2014), s. 190-198 ISSN 1335-8987. [Deformation and Fracture in PM Materials. Stará Lesná, 26.10.2014-29.10.2014] R&D Projects: GA MPO FR-TI4/406; GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : powder materials * Ni-based PM superalloy * grip of creep machine * oxidation Subject RIV: JG - Metallurgy

  3. Anisotropic constitutive equations for the viscoplastic behaviour of the single crystal superalloy CMSX-4

    International Nuclear Information System (INIS)

    Fleury, G.; Schubert, F.

    1997-09-01

    Nickel-base superalloy blades of the first rotor stage in a gas turbine have to withstand extremely severe thermomechanical loading conditions. Single crystal blades exhibit a highly anisotropic deformation behaviour and are subjected to triaxial stress fields induced by complex cooling systems. Consequently the prediction of their deformation behaviour requires constitutive equations based on multiaxial formulations. The microstructural evolution of γ/γ' superalloys during the service time modifies the material properties and has therefore to be taken into account in the constitutive equations. For the modelling of the anisotropic, viscoplastic behaviour of single crystal blades taking into account the evolution of the microstructure, a microstructure-dependent, orthotropic Hills potential, whose anisotropy coefficients are connected to the edge length of the γ'-particles, is applied. The prediction was validated by investigating the deformation behaviour of the superalloy CMSX-4 in the range of temperatures [750 C-950 C]. If the shape of γ'-particles remain cubic, for example, in creep testing at low temperatures (up to about 850 C), the microstructure-dependent potential leads to the cubic version of the Hills potential. The prediction is in good agreement with creep results for left angle 001 right angle - and left angle 111 right angle - orientated specimens but overestimates the creep resistance of left angle 011 right angle - orientated specimens. (orig.)

  4. Abnormal flow behavior and necklace microstructure of powder metallurgy superalloys with previous particle boundaries (PPBs)

    Energy Technology Data Exchange (ETDEWEB)

    Ning, Yongquan, E-mail: luckyning@nwpu.edu.cn [School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072 (China); Zhou, Cong; Liang, Houquan [School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072 (China); Fu, M.W., E-mail: mmmwfu@polyu.edu.hk [Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China)

    2016-01-15

    Powder metallurgy (P/M) has been introduced as an innovative process to manufacture high performance components with fine, homogenous and segregation-free microstructure. Unfortunately, previous particle boundary (PPB) precipitated during the powder metallurgy process. Since undesirable PPB is detrimental to mechanical properties, hot extrusion or/and isothermal forging are needed. In present research, isothermal compression tests were conducted on P/M FGH4096 superalloys with typical PPBs. Abnormal flow behavior during high-speed deformation has been quantitatively investigated. Caused by the competition mechanism between work-hardening and dynamic-softening, abnormal flow behaves typical four stages (viz., work-hardening, stable, softening and steady). Microstructure observation for hardening or/and softening mechanism has been investigated. Meanwhile, necklace microstructure was observed by scanning electron microscope, and the grain fraction analysis was performed by using electron backscatter diffraction. Transmission electron microscopy was used for characterizing the boundary structure. Necklace microstructural mechanism for processing P/M superalloys has been developed, and the dynamic recrystallization model has also been conducted. Bulge–corrugation model is the primary nucleation mechanism for P/M superalloys with PPBs. When PPB is entirely covered with new grains, necklace microstructure has formed. Bulge–corrugation mechanism can repeatedly take place in the following necklace DRX.

  5. Phase-transformation and subgrain-deformation characteristics in a cobalt-based superalloy

    International Nuclear Information System (INIS)

    Benson, M.L.; Reetz, B.; Liaw, P.K.; Reimers, W.; Choo, H.; Brown, D.W.; Saleh, T.A.; Klarstrom, D.L.

    2011-01-01

    Research highlights: → The mechanical behavior of a cobalt-based superalloy was investigated. → Two diffraction techniques were used to study deformation mechanisms of materials. → In-situ neutron diffraction provides the volume-averaged information. → The peak-profile analysis reveals the information on a subgrain level. → The material exhibited a transformation texture for the HCP phase under loading. - Abstract: A complimentary set of experiments, in situ neutron diffraction and ex situ synchrotron X-ray diffraction, were used to study the phase-transformation and subgrain-deformation characteristics of a cobalt-based superalloy. The neutron diffraction indicated a strain-induced phase transformation in the cobalt-based superalloy under uniaxial tension and compression. The synchrotron X-ray diffraction revealed stacking-fault accumulation and twinning under the same loading conditions. The extent of transformation was found to be greater under tension than under compression. Tensile plastic strains below 2% were accommodated by the stacking-fault creation, while those greater than 2% were accommodated by the phase transformation. Twinning was found to be more active under compressive loading than under tensile loading.

  6. Molecular dynamics simulation of edge dislocation piled at cuboidal precipitate in Ni-based superalloy

    International Nuclear Information System (INIS)

    Yashiro, Kisaragi; Naito, Masato; Tomita, Yoshihiro

    2003-01-01

    In order to clarify the fundamental mechanism of dislocations in the γ/γ' microstructure of Ni-based superalloy, three molecular dynamics simulations are conducted on the behavior of edge dislocations nucleated from a free surface and proceeding in the pure Ni matrix (γ) toward cuboidal Ni 3 Al precipitates (γ') under shear force. One involves dislocations near the apices of two precipitates adjoining each other with the distance of 0.04 μm, as large as the width of the γ channel in real superalloys. Others simulate dislocations piled at the precipitates as well, however, the scale of the microstructure is smaller than that in real superalloys by one order of magnitude, and one of them have precipitates with atomistically sharp edge. Dislocations are pinned at precipitates and bowed-out in the γ channel, then they begin to penetrate into the precipitate at the edge in both the real-scale and smaller microstructures when the precipitates have blunt edges. On the other hand, an edge dislocation splits into a superpartial in the γ' precipitate and a misfit screw dislocation bridging between two adjacent precipitates at the atomistically sharp edge of γ' precipitates. It is also observed that two superpartials glide in the precipitate as a superdislocation with anti-phase boundary (APB), of which the width is evaluated to be about 4 nm. (author)

  7. Kink structures induced in nickel-based single crystal superalloys by high-Z element migration

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Fei; Zhang, Jianxin [Key Laboratory for Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Mao, Shengcheng [Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100124 (China); Jiang, Ying [Center of Electron Microscopy and State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Feng, Qiang [National Center for Materials Service Safety, University of Science and Technology Beijing, Beijing 100083 (China); State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Shen, Zhenju; Li, Jixue; Zhang, Ze [Center of Electron Microscopy and State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Han, Xiaodong [Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100124 (China)

    2015-01-05

    Highlights: • Innovative kink structures generate at the γ/γ′ interfaces in the crept superalloy. • Clusters of heavy elements congregate at the apex of the kinks. • Dislocation core absorbs hexagonal structural high-Z elements. - Abstract: Here, we investigate a new type of kink structure that is found at γ/γ′ interfaces in nickel-based single crystal superalloys. We studied these structures at the atomic and elemental level using aberration corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). The core of the dislocation absorbs high-Z elements (i.e., Co and Re) that adopt hexagonal arrangements, and it extrudes elements (i.e., Ni and Al) that adopt face centered cubic (fcc) structures. High-Z elements (i.e., Ta and W) and Cr, which is a low-Z element, are stabilized in body centered cubic (bcc) arrangements; Cr tends to behave like Re. High-Z elements, which migrate and adopt a hexagonal structure, induce kink formation at γ/γ′ interfaces. This process must be analyzed to fully understand the kinetics and dynamics of creep in nickel-based single crystal superalloys.

  8. Microstructural response to heat affected zone cracking of prewelding heat-treated Inconel 939 superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, M.A., E-mail: mgonzalez@comimsa.com.mx [Facultad de Ingenieria Mecanica y Electrica (FIME-UANL), Av. Universidad s/n. Ciudad Universitaria, C.P.66451 San Nicolas de los Garza, N.L. (Mexico); Martinez, D.I., E-mail: dorairma@yahoo.com [Facultad de Ingenieria Mecanica y Electrica (FIME-UANL), Av. Universidad s/n. Ciudad Universitaria, C.P.66451 San Nicolas de los Garza, N.L. (Mexico); Perez, A., E-mail: betinperez@hotmail.com [Facultad de Ingenieria Mecanica y Electrica (FIME-UANL), Av. Universidad s/n. Ciudad Universitaria, C.P.66451 San Nicolas de los Garza, N.L. (Mexico); Guajardo, H., E-mail: hguajardo@frisa.com [FRISA Aerospace, S.A. de C.V., Valentin G. Rivero No. 200, Col. Los Trevino, C.P. 66150, Santa Caterina N.L. (Mexico); Garza, A., E-mail: agarza@comimsa.com [Corporacion Mexicana de Investigacion en Materiales S.A. de C.V. (COMIMSA), Ciencia y Tecnologia No.790, Saltillo 400, C.P. 25295 Saltillo Coah. (Mexico)

    2011-12-15

    The microstructural response to cracking in the heat-affected zone (HAZ) of a nickel-based IN 939 superalloy after prewelding heat treatments (PWHT) was investigated. The PWHT specimens showed two different microstructures: 1) spherical ordered {gamma} Prime precipitates (357-442 nm), with blocky MC and discreet M{sub 23}C{sub 6} carbides dispersed within the coarse dendrites and in the interdendritic regions; and 2) ordered {gamma} Prime precipitates in 'ogdoadically' diced cube shapes and coarse MC carbides within the dendrites and in the interdendritic regions. After being tungsten inert gas welded (TIG) applying low heat input, welding speed and using a more ductile filler alloy, specimens with microstructures consisting of spherical {gamma} Prime precipitate particles and dispersed discreet MC carbides along the grain boundaries, displayed a considerably improved weldability due to a strong reduction of the intergranular HAZ cracking associated with the liquation microfissuring phenomena. - Highlights: Black-Right-Pointing-Pointer Homogeneous microstructures of {gamma} Prime spheroids and discreet MC carbides of Ni base superalloys through preweld heat treatments. Black-Right-Pointing-Pointer {gamma} Prime spheroids and discreet MC carbides reduce the intergranular HAZ liquation and microfissuring of Nickel base superalloys. Black-Right-Pointing-Pointer Microstructure {gamma} Prime spheroids and discreet blocky type MC carbides, capable to relax the stress generated during weld cooling. Black-Right-Pointing-Pointer Low welding heat input welding speeds and ductile filler alloys reduce the HAZ cracking susceptibility.

  9. Detection of creep damage in a nickel base superalloy using NDE techniques

    International Nuclear Information System (INIS)

    Carreon, H.; Mora, B.; Barrera, G.

    2009-10-01

    Due to elevated temperatures, excessive stresses and severed corrosion conditions, turbine engine components are subject to creep processes that limit the components life such as a turbine bucket. The failure mechanism of a turbine bucket is related primarily to creep and corrosion and secondarily to thermal fatigue. As a result, it is desirable to assess the current conditions of such turbine component. This study uses the eddy current nondestructive evaluation technique in an effort to monitor the creep damage in a nickel base super-alloy, turbine bucket after service. The experimental results show an important electrical conductivity variation in eddy current images on the creep damage zone of nickel base super-alloy samples cut from a turbine bucket. Thermoelectric power measurements were also conducted in order to obtain a direct correlation between the presence of material changes due to creep damage and the electrical conductivity measurements. This research work shows an alternative non-destructive method in order to detect creep damage in a nickel base super-alloy turbine bucket. (Author)

  10. A continuum model for the anisotropic creep of single crystal nickel-based superalloys

    International Nuclear Information System (INIS)

    Prasad, Sharat C.; Rajagopal, K.R.; Rao, I.J.

    2006-01-01

    In this paper, we extend the constitutive theory developed by Prasad et al. [Prasad SC, Rao IJ, Rajagopal KR. A continuum model for the creep of single crystal nickel-base superalloys. Acta Mater 2005;53(3):669-79], to describe the creep anisotropy associated with crystallographic orientation in single crystal nickel-based superalloys. The constitutive theory is cast within a general thermodynamic framework that has been developed to describe the response of materials capable of existing in multiple stress free configurations ('natural configurations'). Central to the theory is the prescription of the forms for the stored energy and rate of dissipation functions. The stored energy reflects the fact that the elastic response exhibits cubic symmetry. The model takes into account the fact that the symmetry of single crystals does not change with inelastic deformation. The rate of dissipation function is also chosen to be anisotropic, in that it reflects invariance to transformations that belong to the cubic symmetry group. The model is used to simulate uniaxial creep of single crystal nickel-based superalloy CMSX-4 for loading along the , and orientations. The predictions of the theory agree well with the experimental data

  11. A new method to predict the metadynamic recrystallization behavior in a typical nickel-based superalloy

    International Nuclear Information System (INIS)

    Lin, Y.C.; Chen, Xiao-Min; Chen, Ming-Song; Wen, Dong-Xu; Zhou, Ying; He, Dao-Guang

    2016-01-01

    The metadynamic recrystallization (MDRX) behaviors of a typical nickel-based superalloy are investigated by two-pass hot compression tests and four conventional stress-based conventional approaches (offset stress method, back-extrapolation stress method, peak stress method, and mean stress method). It is found that the conventional stress-based methods are not suitable to evaluate the MDRX softening fractions for the studied superalloy. Therefore, a new approach, 'maximum stress method', is proposed to evaluate the MDRX softening fraction. Based on the proposed method, the effects of deformation temperature, strain rate, initial average grain size, and interpass time on MDRX behaviors are discussed in detail. Results show that MDRX softening fraction is sensitive to deformation parameters. The MDRX softening fraction rapidly increases with the increase of deformation temperature, strain rate, and interpass time. The MDRX softening fraction in the coarse-grain material is lower than that in the fine-grain material. Moreover, the observed microstructures indicate that the initial coarse grains can be effectively refined by MDRX. Based on the experimental results, the kinetics equations are established and validated to describe the MDRX behaviors of the studied superalloy. (orig.)

  12. Implementation of a structural dependent model for the superalloy IN738LC in ABAQUS-code

    International Nuclear Information System (INIS)

    Wolters, J.; Betten, J.; Penkalla, H.J.

    1994-05-01

    Superalloys, mainly consisting of nickel, are used for applications in aerospace as well as in stationary gas turbines. In the temperature range above 800 C the blades, which are manufactured of these superalloys, are subjected to high centrifugal forces and thermal induced loads. For computer based analysis of the thermo-mechanical behaviour of the blades models for the stress-strain behaviour are necessary. These models have to give a reliable description of the stress-strain behaviour, with emphasis on inelastic affects. The implementation of the model in finite element codes requires a numerical treatment of the constitutive equations with respect to the given interface of the used code. In this paper constitutive equations for the superalloy IN738LC are presented and the implementation in the finite element code ABAQUS with the numerical preparation of the model is described. In order to validate the model calculations were performed for simple uniaxial loading conditions as well as for a complete cross section of a turbine blade under combined thermal and mechanical loading. The achieved results were compared with those of additional calculations by using ABAQUS, including Norton's law, which was already implemented in this code. (orig.) [de

  13. Tensile properties and temperature-dependent yield strength prediction of GH4033 wrought superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Jianzuo [State Key Laboratory of Coal Mine Disaster Dynamics and Control and College of Aerospace Engineering, Chongqing University, Chongqing 400030 (China); Li, Weiguo, E-mail: wgli@cqu.edu.cn [State Key Laboratory of Coal Mine Disaster Dynamics and Control and College of Aerospace Engineering, Chongqing University, Chongqing 400030 (China); Zhang, Xianhe; Kou, Haibo; Shao, Jiaxing; Geng, Peiji; Deng, Yong [State Key Laboratory of Coal Mine Disaster Dynamics and Control and College of Aerospace Engineering, Chongqing University, Chongqing 400030 (China); Fang, Daining [LTCS and College of Engineering, Peking University, Beijing 100871 (China)

    2016-10-31

    The tensile properties of superalloy GH4033 have been evaluated at temperatures ranging from room temperature to 1000 °C. Fracture surfaces and precipitation were observed using a field-emission scanning electron microscope (FE-SEM). The alloy mainly consisted of γ’ precipitate particles homogeneously dispersed in the γ matrix interior. The effects of dynamic strain aging and precipitation on the strength were verified. A temperature-dependent yield strength model was developed to describe the temperature and precipitation effects on the alloy's yield behaviour. The model is able to consider the effect of precipitation strengthening on the yield strength. The yield behaviour of the precipitation-strengthened superalloy was demonstrated to be adequately predictable over a wide range of temperatures. Note that this model reflects the quantitative relationship between the yield strength of the precipitation-strengthened superalloy and the temperature, the elastic modulus, the specific heat capacity at constant pressure, Poisson's ratio, the precipitate particle size and the volume fraction of the particles.

  14. Welding Metallurgy of Nickel-Based Superalloys for Power Plant Construction

    Science.gov (United States)

    Tung, David C.

    Increasing the steam temperature and pressure in coal-fired power plants is a perpetual goal driven by the pursuit of increasing thermal cycle efficiency and reducing fuel consumption and emissions. The next target steam operating conditions, which are 760°C (1400°F) and 35 MPa (5000 psi) are known as Advanced Ultra Supercritical (AUSC), and can reduce CO2 emissions up to 13% but this cannot be achieved with traditional power plant construction materials. The use of precipitation-strengthened Nickel-based alloys (superalloys) is required for components which will experience the highest operating temperatures. The leading candidate superalloys for power plant construction are alloys 740H, 282, and 617. Superalloys have excellent elevated temperature properties due to careful microstructural design which is achieved through very specific heat treatments, often requiring solution annealing or homogenization at temperatures of 1100 °C or higher. A series of postweld heat treatments was investigated and it was found that homogenization steps before aging had no noticeable effect on weld metal microhardness, however; there were clear improvements in weld metal homogeneity. The full abstract can be viewed in the document itself.

  15. The High Temperature Tensile and Creep Behaviors of High Entropy Superalloy.

    Science.gov (United States)

    Tsao, Te-Kang; Yeh, An-Chou; Kuo, Chen-Ming; Kakehi, Koji; Murakami, Hideyuki; Yeh, Jien-Wei; Jian, Sheng-Rui

    2017-10-04

    This article presents the high temperature tensile and creep behaviors of a novel high entropy alloy (HEA). The microstructure of this HEA resembles that of advanced superalloys with a high entropy FCC matrix and L1 2 ordered precipitates, so it is also named as "high entropy superalloy (HESA)". The tensile yield strengths of HESA surpass those of the reported HEAs from room temperature to elevated temperatures; furthermore, its creep resistance at 982 °C can be compared to those of some Ni-based superalloys. Analysis on experimental results indicate that HESA could be strengthened by the low stacking-fault energy of the matrix, high anti-phase boundary energy of the strengthening precipitate, and thermally stable microstructure. Positive misfit between FCC matrix and precipitate has yielded parallel raft microstructure during creep at 982 °C, and the creep curves of HESA were dominated by tertiary creep behavior. To the best of authors' knowledge, this article is the first to present the elevated temperature tensile creep study on full scale specimens of a high entropy alloy, and the potential of HESA for high temperature structural application is discussed.

  16. Od melancholii do rozpaczy. O prozie Andrzeja Stasiuka

    Directory of Open Access Journals (Sweden)

    Claudia Snochowska-Gonzalez

    2014-06-01

    Full Text Available From melancholy to despair. About Andrzej Stasiuk’s prose works In Moja Europa, Jadąc do Babadag and Fado Andrzej Stasiuk describes his travelling to the countries of the East-Central Europe: its diminished, forgotten part, lying on the margins of History and Progress. It is a land of melancholy, of the eternal emptiness and lack. To praise it means to give an ironic response to the enthusiasm of a “return to the West”, to the attempts to meet East-European stigma and to the West’s fear of East-European ferocity. What is the source of this melancholy? Stasiuk refers to Cioran, his philosophy of history, his resignation and his belief in the bankruptcy of the European civilization. We know, however, that in the case of Cioran melancholy covers the memory of philosopher’s commitment to Romanian fascism; his subsequent melancholy replaces responsibility. What are the wounds and silenced victims hiding in Stasiuk’s melancholic landscape? What kind of responsibility does he not want to accept? In his next book, Dziennik pisany później, Stasiuk comes back to the same countries, this time not trying to escape the hell of questions about the East-European ethnic carnage. The author of the article analyses his turning point, using the terminology developed in Peter Hallward’s Absolutely Post-colonial to describe the dynamics between two tendencies: singular and specific.   Od melancholii do rozpaczy. O prozie Andrzeja Stasiuka W Mojej Europie, Jadąc do Babadag i Fado Andrzej Stasiuk podróżuje po krajach Europy Środkowo-Wschodniej. To Europa pomniejsza, zapomniana, na marginesie Historii i Postępu. Jest to kraina melancholii, pustki i wiecznego braku. Opiewanie jej staje się ironiczną odpowiedzią na entuzjazm „powrotu do Zachodu”, na próby sprostania wschodnioeuropejskiemu piętnu i na zachodnie przerażenie wschodnioeuropejską dzikością. Skąd się jednak bierze spowijająca ją melancholia? Stasiuk powołuje się na

  17. Vitamin and Mineral Supplement Fact Sheets

    Science.gov (United States)

    ... website Submit Search NIH Office of Dietary Supplements Vitamin and Mineral Supplement Fact Sheets Search the list ... Supplements: Background Information Botanical Dietary Supplements: Background Information Vitamin and Mineral Fact Sheets Botanical Supplement Fact Sheets ...

  18. Investigation of microstructure changes in ODS-EUROFER after hydrogen loading

    International Nuclear Information System (INIS)

    Emelyanova, O.V.; Ganchenkova, M.G.; Malitskii, E.; Yagodzinskyy, Y.N.; Klimenkov, M.; Borodin, V.A.; Vladimirov, P.V.; Lindau, R.; Möslang, A.; Hänninen, H.

    2016-01-01

    The effect of hydrogen on the microstructure of mechanically tested ODS-EUROFER steel was investigated by means of transmission electron microscopy, thermal desorption spectroscopy, and atomistic simulations. The presence of yttrium oxide particles notably increases hydrogen uptake in ODS-EUROFER steel as compared to ODS-free EUROFER 97. Under tensile loading, hydrogen accumulation promotes the loss of cohesion at the oxide particle interfaces. First-principles molecular dynamics simulations indicate that hydrogen can be trapped at nanoparticle/matrix interface, creating OH-groups. The accumulation of hydrogen atoms at the oxide particle surface can be the reason for the observed hydrogen-induced oxide/matrix interface weakening and de-cohesion under the action of external tensile stress.

  19. Microstructural Evolution of Advanced Radiation-Resistant ODS Steel with Different Lengths of Mechanical Alloying Time

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Sanghoon; Kim, Ga Eon; Kang, Suk Hoon; Kim, Tae Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    Austenitic stainless steel may be one of the candidates because of good strength and corrosion resistance at the high temperatures, however irradiation swelling well occurred to 120dpa at high temperatures and this leads the decrease of the mechanical properties and dimensional stability. Compared to this, ferritic/ martensitic steel is a good solution because of excellent thermal conductivity and good swelling resistance. Unfortunately, the available temperature range of ferritic/martensitic steel is limited up to 650 .deg. C. ODS steel is the most promising structural material because of excellent creep and irradiation resistance by uniformly distributed nano-oxide particles with a high density which is extremely stable at the high temperature in ferritic/martensitic matrix. In this study, powder properties and microstructures of the ODS steel with different length of mechanical alloying time was investigated. The ODS steel milled 5h showed homogeneous grain structure with the highest hardness.

  20. Structure of Oxide Nanoparticles in Fe-16Cr MA/ODS Ferritic Steel

    Energy Technology Data Exchange (ETDEWEB)

    Hsiung, L; Fluss, M; Kimura, A

    2010-04-06

    Oxide nanoparticles in Fe-16Cr ODS ferritic steel fabricated by mechanical alloying (MA) method have been examined using high-resolution transmission electron microscopy (HRTEM) techniques. A partial crystallization of oxide nanoparticles was frequently observed in as-fabricated ODS steel. The crystal structure of crystalline oxide particles is identified to be mainly Y{sub 4}Al{sub 2}O{sub 9} (YAM) with a monoclinic structure. Large nanoparticles with a diameter larger than 20 nm tend to be incoherent and have a nearly spherical shape, whereas small nanoparticles with a diameter smaller than 10 nm tend to be coherent or semi-coherent and have faceted boundaries. The oxide nanoparticles become fully crystallized after prolonged annealing at 900 C. These results lead us to propose a three-stage formation mechanism of oxide nanoparticles in MA/ODS steels.

  1. Microstructural Evolution of Advanced Radiation-Resistant ODS Steel with Different Lengths of Mechanical Alloying Time

    International Nuclear Information System (INIS)

    Noh, Sanghoon; Kim, Ga Eon; Kang, Suk Hoon; Kim, Tae Kyu

    2015-01-01

    Austenitic stainless steel may be one of the candidates because of good strength and corrosion resistance at the high temperatures, however irradiation swelling well occurred to 120dpa at high temperatures and this leads the decrease of the mechanical properties and dimensional stability. Compared to this, ferritic/ martensitic steel is a good solution because of excellent thermal conductivity and good swelling resistance. Unfortunately, the available temperature range of ferritic/martensitic steel is limited up to 650 .deg. C. ODS steel is the most promising structural material because of excellent creep and irradiation resistance by uniformly distributed nano-oxide particles with a high density which is extremely stable at the high temperature in ferritic/martensitic matrix. In this study, powder properties and microstructures of the ODS steel with different length of mechanical alloying time was investigated. The ODS steel milled 5h showed homogeneous grain structure with the highest hardness

  2. Effect of irradiation temperature on microstructure of ferritic-martensitic ODS steel

    Science.gov (United States)

    Klimenkov, M.; Lindau, R.; Jäntsch, U.; Möslang, A.

    2017-09-01

    The EUROFER-ODS alloy with 0.5% Y2O3 was neutron irradiated with doses up to 16.2 dpa at 250 °C, 350 °C and 450 °C. The radiation induced changes in the microstructure (e.g. dislocation loops and voids) were investigated using transmission electron microscopy (TEM). The number density of radiation induced defects was found to be significantly lower than in EUROFER 97 irradiated at the same conditions. It was found that the appearance and extent of radiation damage strongly depend not only on the irradiation temperature but also on the local number density and size distribution of ODS particles. The higher number density of dislocation loops and voids was found in the local areas with low number density of ODS particles. The interstitial loops with Burgers vector of both ½ and types were detected by imaging using different diffraction conditions.

  3. Oxidation behavior of austenitic iron-base ODS alloy in supercritical water

    Energy Technology Data Exchange (ETDEWEB)

    Behnamian, Y.; Dong, Z.; Zahiri, R.; Kohandehghan, A.; Mitlin, D., E-mail: behnamia@ualberta.ca, E-mail: zdong@ualberta.ca, E-mail: kohandeh@ualberta.ca, E-mail: rzahiris@ualberta.ca, E-mail: dave.mitlin@ualberta.ca [Univ. of Alberta, Edmondon, AB (Canada); Zhou, Z., E-mail: zhouzhj@mater.ustb.edu.cn [Univ. of Science and Tech. Beijing, Beijing (China); Chen, W.; Luo, J., E-mail: weixing.chen@ualberta.ca, E-mail: Jingli.luo@ualberta.ca [Univ. of Alberta, Edmonton, AB (Canada); Zheng, W., E-mail: wenyue@nrcan.gc.ca [Natural Resources Canada, Canmet MATERIALS, Hamilton, ON (Canada); Guzonas, D. [Atomic Energy of Canada Limited, Chalk River, ON (Canada)

    2014-07-01

    In this study, the effect of exposure time on the corrosion of the 304 stainless steel based oxide dispersion strengthened alloy, SS304ODS, in supercritical water was investigated at 650 {sup o}C with constant dissolved oxygen concentration. The results show that the oxidation of SS304ODS in supercritical water followed a parabolic law at 650 {sup o}C. Discontinuous oxide scale with two distinct layers has formed after 550 hours. The inner layer was chromium-rich while the outer layer was iron-rich (Magnetite). The oxide islands grow with increasing the exposure time. With increasing exposure time, the quantity of oxide islands increased in which major preferential growth along oxide-substrate interface was observed. The possible mechanism of SS304ODS oxidation in supercritical water was also discussed. (author)

  4. Characterization of precipitates in nano structured 14% Cr ODS alloys for fusion application

    International Nuclear Information System (INIS)

    He, P.; Klimenkov, M.; Lindau, R.; Möslang, A.

    2012-01-01

    Highlights: ► We examine Ti influence on microstructure and mechanical properties of ODS steels. ► Ti addition leads to bimodal grain size distribution. ► The formation of Ti oxide and Y–Ti–O particles is observed in Ti-containing steels. ► The best nanoparticle refinement and tensile strength are obtained with 0.3% Ti. ► Ti exhibits adverse effect on the Charpy impact property. - Abstract: Oxide dispersion strengthened (ODS) reduced activation ferritic (RAF) steels, have been considered as promising materials for application in fusion power reactors up to about 750 °C. Four ODS RAF steels, with compositions of Fe–13.5Cr–2W–(0–0.2–0.3–0.4)Ti–0.3Y 2 O 3 (in wt.%) were produced by powder metallurgy technique. For the different Ti-contents, the correlation between microstructure and mechanical properties was analyzed by means of scanning electron microscope (SEM) and transmission electron microscope (TEM) equipped with energy- dispersive X-ray spectrometer (EDX) and electron energy loss spectrometer (EELS). A bimodal grain size distribution was observed in all as-hipped Ti-containing ODS alloys. These alloys consisted of coarse grains typical ranging from 1 μm to 8 μm and fine grains well below 1 μm in diameter. The addition of Ti resulted in the formation of spherical Ti oxides rather than Cr oxides owing to the stronger affinity of Ti. The influence of Ti on particle size refinement was striking and the optimum effect was obtained when adding 0.3% Ti. Generally the hardness increased consistently with increasing in Ti content. The ODS alloying with 0.3% Ti exhibit the highest strength due to the optimum refinement of mean ODS particle size.

  5. Self-ion Irradiation Damage of F/M and ODS steels

    International Nuclear Information System (INIS)

    Kang, Suk Hoon; Chun, Young-Bum; Noh, Sanghoon; Jang, Jinsung; Kim, Tae Kyu

    2014-01-01

    Oxide dispersion strengthened (ODS) ferritic steels are potential high-temperature materials that are stabilized by dispersed particles at elevated temperatures. These dispersed particles improve the tensile strength and creep rupture strength, they are expected to increase the operation temperature up to approximately 650 .deg. C and also enhance the energy efficiency of the fusion reactor. Some reports described that the nano-clusters are strongly resistant to coarsening by annealing up to 1000 .deg. C, and nanoclusters do not change after ion irradiation up to 0.7 dpa at 300 .deg. C. ODS steels will be inevitably exposed to neutron irradiation condition; the irradiation damages, creep and swelling are always great concern. The dispersed oxide particles are believed to determine the performance of the steel, even the radiation resistance. In this study, F/M and ODS model alloys of Korea Atomic Energy Research Institute (KAERI) were irradiated by Fe 3+ self-ion to emulate the neutron irradiation effect. In this study, Fe 3+ self-ion irradiation is used as means of introducing radiation damage in F/M steel and ODS steel. The ion accelerator named DuET (in Kyoto University, Japan) was used for irradiation of Fe 3+ ion by 6.4 MeV at 300 .deg. C. The maximum damage rate in F/M and ODS steels were estimated roughly 6 dpa. After radiation, point or line defects were dominantly observed in F/M steel, on the other hands, small circular cavities were typically observed in ODS steel. Nanoindentation is a useful tool to determine the irradiationinduced hardness change in the damage layer of ionirradiated iron base alloys

  6. Metabolic cooperation of ascorbic acid and glutathione in normal and vitamin C-deficient ODS rats.

    Science.gov (United States)

    Wang, Y; Kashiba, M; Kasahara, E; Tsuchiya, M; Sato, E F; Utsumi, K; Inoue, M

    2001-01-01

    Although the coordination of various antioxidants is important for the protection of organisms from oxidative stress, dynamic aspects of the interaction of endogenous antioxidants in vivo remain to be elucidated. We studied the metabolic coordination of two naturally occurring water-soluble antioxidants, ascorbic acid (AA) and reduced glutathione (GSH), in liver, kidney and plasma of control and scurvy-prone osteogenic disorder Shionogi (ODS) rats that hereditarily lack the ability to synthesize AA. When supplemented with AA, its levels in liver and kidney of ODS rats increased to similar levels of those in control rats. Hepato-renal levels of glutathione were similar with the two animal groups except for the slight increase in its hepatic levels in AA-supplemented ODS rats. Administration of L-buthionine sulfoximine (BSO), a specific inhibitor of GSH synthesis, rapidly decreased the hepato-renal levels of glutathione in a biphasic manner, a rapid phase followed by a slower phase. Kinetic analysis revealed that glutathione turnover was enhanced significantly in liver mitochondria and renal cytosol of ODS rats. Administration of BSO significantly increased AA levels in the liver and kidney of control rats but decreased them in AA-supplemented ODS rats. Kinetic analysis revealed that AA is synthesized by control rat liver by some BSO-enhanced mechanism and the de novo synthesized AA is transferred to the kidney. Such a coordination of the metabolism of GSH and AA in liver and kidney is suppressed in AA-deficient ODS rats. These and other results suggest that the metabolism of AA and GSH forms a compensatory network by which oxidative stress can be decreased.

  7. Rasch-built Overall Disability Scale (R-ODS) for immune-mediated peripheral neuropathies.

    Science.gov (United States)

    van Nes, S I; Vanhoutte, E K; van Doorn, P A; Hermans, M; Bakkers, M; Kuitwaard, K; Faber, C G; Merkies, I S J

    2011-01-25

    To develop a patient-based, linearly weighted scale that captures activity and social participation limitations in patients with Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), and gammopathy-related polyneuropathy (MGUSP). A preliminary Rasch-built Overall Disability Scale (R-ODS) containing 146 activity and participation items was constructed, based on the WHO International Classification of Functioning, Disability and Health, literature search, and patient interviews. The preliminary R-ODS was assessed twice (interval: 2-4 weeks; test-retest reliability studies) in 294 patients who experienced GBS in the past (n = 174) or currently have stable CIDP (n = 80) or MGUSP (n = 40). Data were analyzed using the Rasch unidimensional measurement model (RUMM2020). The preliminary R-ODS did not meet the Rasch model expectations. Based on disordered thresholds, misfit statistics, item bias, and local dependency, items were systematically removed to improve the model fit, regularly controlling the class intervals and model statistics. Finally, we succeeded in constructing a 24-item scale that fulfilled all Rasch requirements. "Reading a newspaper/book" and "eating" were the 2 easiest items; "standing for hours" and "running" were the most difficult ones. Good validity and reliability were obtained. The R-ODS is a linearly weighted scale that specifically captures activity and social participation limitations in patients with GBS, CIDP, and MGUSP. Compared to the Overall Disability Sum Score, the R-ODS represents a wider range of item difficulties, thereby better targeting patients with different ability levels. If responsive, the R-ODS will be valuable for future clinical trials and follow-up studies in these conditions.

  8. Experimental study of the reactions of limonene with OH and OD radicals: kinetics and products.

    Science.gov (United States)

    Braure, Tristan; Bedjanian, Yuri; Romanias, Manolis N; Morin, Julien; Riffault, Véronique; Tomas, Alexandre; Coddeville, Patrice

    2014-10-09

    The kinetics of the reactions of limonene with OH and OD radicals has been studied using a low-pressure flow tube reactor coupled with a quadrupole mass spectrometer: OH + C10H16 → products (1), OD + C10H16 → products (2). The rate constants of the title reactions were determined using four different approaches: either monitoring the kinetics of OH (OD) radicals or limonene consumption in excess of limonene or of the radicals, respectively (absolute method), and by the relative rate method using either the reaction OH (OD) + Br2 or OH (OD) + DMDS (dimethyl disulfide) as the reference one and following HOBr (DOBr) formation or DMDS and limonene consumption, respectively. As a result of the absolute and relative measurements, the overall rate coefficients, k1 = (3.0 ± 0.5) × 10(-11) exp((515 ± 50)/T) and k2 = (2.5 ± 0.6) × 10(-11) exp((575 ± 60)/T) cm(3) molecule(-1) s(-1), were determined at a pressure of 1 Torr of helium over the temperature ranges 220-360 and 233-353 K, respectively. k1 was found to be pressure independent over the range 0.5-5 Torr. There are two possible pathways for the reaction between OH (OD) and limonene: addition of the radical to one of the limonene double bonds (reactions 1a and 2a ) and abstraction of a hydrogen atom (reactions 1b and 2b ), resulting in the formation of H2O (HOD). Measurements of the HOD yield as a function of temperature led to the following branching ratio of the H atom abstraction channel: k2b/k2 = (0.07 ± 0.03) × exp((460 ± 140)/T) for T = (253-355) K.

  9. Selectively reflective transparent sheets

    Science.gov (United States)

    Waché, Rémi; Florescu, Marian; Sweeney, Stephen J.; Clowes, Steven K.

    2015-08-01

    We investigate the possibility to selectively reflect certain wavelengths while maintaining the optical properties on other spectral ranges. This is of particular interest for transparent materials, which for specific applications may require high reflectivity at pre-determined frequencies. Although there exist currently techniques such as coatings to produce selective reflection, this work focuses on new approaches for mass production of polyethylene sheets which incorporate either additives or surface patterning for selective reflection between 8 to 13 μ m. Typical additives used to produce a greenhouse effect in plastics include particles such as clays, silica or hydroxide materials. However, the absorption of thermal radiation is less efficient than the decrease of emissivity as it can be compared with the inclusion of Lambertian materials. Photonic band gap engineering by the periodic structuring of metamaterials is known in nature for producing the vivid bright colors in certain organisms via strong wavelength-selective reflection. Research to artificially engineer such structures has mainly focused on wavelengths in the visible and near infrared. However few studies to date have been carried out to investigate the properties of metastructures in the mid infrared range even though the patterning of microstructure is easier to achieve. We present preliminary results on the diffuse reflectivity using FDTD simulations and analyze the technical feasibility of these approaches.

  10. First results from the commissioning of the BGO-OD experiment at ELSA

    Science.gov (United States)

    Bella, Andreas

    2014-11-01

    The BGO-OD experiment at the ELSA accelerator facility in Bonn combines the highly segmented BGO calorimeter with a particle tracking magnetic spectrometer at forward angles. An extensive physics program using an energy tagged Bremsstrahlung photon beam is planned. The commissioning phase of the experiment is recently complete, enhancements for the BGO-OD experiment are nevertheless in development. Recent results from the analysis of the commissioning data, which includes particle track reconstruction in the forward spectrometer and momentum reconstruction with the BGO calorimeter are presented.

  11. Development of ODS (oxide dispersion strengthened) ferritic-martensitic steels for fast reactor fuel cladding

    International Nuclear Information System (INIS)

    Ukai, Shigeharu

    2000-01-01

    In order to attain higher burnup and higher coolant outlet temperature in fast reactor, oxide dispersion strengthened (ODS) ferritic-martensitic steels were developed as a long life fuel cladding. The improvement in formability and ductility, which are indispensable in the cold-rolling method for manufacturing cladding tube, were achieved by controlling the microstructure using techniques such as recrystallization heat-treatment and α to γ phase transformation. The ODS ferritic-martensitic cladding tubes manufactured using these techniques have the highest internal creep rupture strength in the world as ferritic stainless steels. Strength level approaches adequate value at 700degC, which meets the requirement for commercial fast reactors. (author)

  12. Development of ODS FeCrAl alloys for accident-tolerant fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Dryepondt, Sebastien N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hoelzer, David T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pint, Bruce A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Unocic, Kinga A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-09-18

    FeCrAl alloys are prime candidates for accident-tolerant fuel cladding due to their excellent oxidation resistance up to 1400 C and good mechanical properties at intermediate temperature. Former commercial oxide dispersion strengthened (ODS) FeCrAl alloys such as PM2000 exhibit significantly better tensile strength than wrought FeCrAl alloys, which would alloy for the fabrication of a very thin (~250 m) ODS FeCrAl cladding and limit the neutronic penalty from the replacement of Zr-based alloys by Fe-based alloys. Several Fe-12-Cr-5Al ODS alloys where therefore fabricated by ball milling FeCrAl powders with Y2O3 and additional oxides such as TiO2 or ZrO2. The new Fe-12Cr-5Al ODS alloys showed excellent tensile strength up to 800 C but limited ductility. Good oxidation resistance in steam at 1200 and 1400 C was observed except for one ODS FeCrAl alloy containing Ti. Rolling trials were conducted at 300, 600 C and 800 C to simulate the fabrication of thin tube cladding and a plate thickness of ~0.6mm was reached before the formation of multiple edge cracks. Hardness measurements at different stages of the rolling process, before and after annealing for 1h at 1000 C, showed that a thinner plate thickness could likely be achieved by using a multi-step approach combining warm rolling and high temperature annealing. Finally, new Fe-10-12Cr-5.5-6Al-Z gas atomized powders have been purchased to fabricate the second generation of low-Cr ODS FeCrAl alloys. The main goals are to assess the effect of O, C, N and Zr contents on the ODS FeCrAl microstructure and mechanical properties, and to optimize the fabrication process to improve the ductility of the 2nd gen ODS FeCrAl while maintaining good mechanical strength and oxidation resistance.

  13. Radiation Stability of Nanoclusters in Nano-structured Oxide Dispersion Strengthened (ODS) Steels

    International Nuclear Information System (INIS)

    Certain, Alicia G.; Kuchibhatla, Satyanarayana; Shutthanandan, V.; Allen, T. R.

    2013-01-01

    Nanostructured oxide dispersion strengthened (ODS) steels are considered candidates for nuclear fission and fusion applications at high temperature and dose. The complex oxide nanoclusters in these alloys provide high-temperature strength and are expected to afford better radiation resistance. Proton, heavy ion, and neutron irradiations have been performed to evaluate cluster stability in 14YWT and 9CrODS steel under a range of irradiation conditions. Energy-filtered transmission electron microscopy and atom probe tomography were used in this work to analyze the evolution of the oxide population.

  14. Superfund fact sheet: The remedial program. Fact sheet

    International Nuclear Information System (INIS)

    1992-09-01

    The fact sheet describes what various actions the EPA can take to clean up hazardous wastes sites. Explanations of how the criteria for environmental and public health risk assessment are determined and the role of state and local governments in site remediation are given. The fact sheet is one in a series providing reference information about Superfund issues and is intended for readers with no formal scientific training

  15. First-principles calculations for the elastic properties of Ni-base model superalloys: Ni/Ni3Al multilayers

    International Nuclear Information System (INIS)

    Yun-Jiang, Wang; Chong-Yu, Wang

    2009-01-01

    A model system consisting of Ni[001](100)/Ni 3 Al[001](100) multi-layers are studied using the density functional theory in order to explore the elastic properties of single crystal Ni-based superalloys. Simulation results are consistent with the experimental observation that rafted Ni-base superalloys virtually possess a cubic symmetry. The convergence of the elastic properties with respect to the thickness of the multilayers are tested by a series of multilayers from 2γ'+2γ to 10γ'+10γ atomic layers. The elastic properties are found to vary little with the increase of the multilayer's thickness. A Ni/Ni 3 Al multilayer with 10γ'+10γ atomic layers (3.54 nm) can be used to simulate the mechanical properties of Ni-base model superalloys. Our calculated elastic constants, bulk modulus, orientation-dependent shear modulus and Young's modulus, as well as the Zener anisotropy factor are all compatible with the measured results of Ni-base model superalloys R1 and the advanced commercial superalloys TMS-26, CMSX-4 at a low temperature. The mechanical properties as a function of the γ' phase volume fraction are calculated by varying the proportion of the γ and γ' phase in the multilayers. Besides, the mechanical properties of two-phase Ni/Ni 3 Al multilayer can be well predicted by the Voigt–Reuss–Hill rule of mixtures. (classical areas of phenomenology)

  16. 2012 Swimming Season Fact Sheets

    Science.gov (United States)

    To help beachgoers make informed decisions about swimming at U.S. beaches, EPA annually publishes state-by-state data about beach closings and advisories for the previous year's swimming season. These fact sheets summarize that information by state.

  17. State Fact Sheets on COPD

    Science.gov (United States)

    ... Submit Search The CDC Chronic Obstructive Pulmonary Disease (COPD) Note: Javascript is disabled or is not supported ... message, please visit this page: About CDC.gov . COPD Homepage Data and Statistics Fact Sheets Publications Publications ...

  18. Super ODS steels R and D for fuel cladding of next generation nuclear systems. 5) Mechanical properties and microstructure

    International Nuclear Information System (INIS)

    Kasada, R.; Lee, S.G.; Lee, J.H.; Omura, T.; Zhang, C.H.; Dou, P.; Isselin, J.; Kimura, A.; Inoue, Masaki; Ukai, S.; Ohnuki, S.; Fujisawa, T.; Okuda, T.; Abe, F.

    2009-01-01

    The newly-developed Al-added ODS ferritic steels with an addition of Zr or Hf, so-called super ODS candidate steels, showed good notch-impact properties in the as-received condition with keeping the excellent creep strength. (author)

  19. Australian Government Balance Sheet Management

    OpenAIRE

    Wilson Au-Yeung; Jason McDonald; Amanda Sayegh

    2006-01-01

    Since almost eliminating net debt, the Australian Government%u2019s attention has turned to the financing of broader balance sheet liabilities, such as public sector superannuation. Australia will be developing a significant financial asset portfolio in the %u2018Future Fund%u2019 to smooth the financing of expenses through time. This raises the significant policy question of how best to manage the government balance sheet to reduce risk. This paper provides a framework for optimal balance sh...

  20. Energy information sheets, July 1998

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-07-01

    The National Energy Information Center (NEIC), as part of its mission, provides energy information and referral assistance to Federal, State, and local governments, the academic community, business and industrial organizations, and the public. The Energy Information Sheets was developed to provide general information on various aspects of fuel production, prices, consumption, and capability. Additional information on related subject matter can be found in other Energy Information Administration (EIA) publications as referenced at the end of each sheet.

  1. Energy information sheets, September 1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-09-01

    The National Energy Information Center (NEIC), as part of its mission, provides energy information and referral assistance to Federal, State, and local governments, the academic community, business and industrial organizations, and the public. The Energy Information Sheets was developed to provide general information on various aspects of fuel production, prices, consumption, and capability. Additional information on related subject matter can be found in other Energy Information Administration (EIA) publications as referenced at the end of each sheet.

  2. Radiation response of ODS ferritic steels with different oxide particles under ion-irradiation at 550 °C

    Science.gov (United States)

    Song, Peng; Morrall, Daniel; Zhang, Zhexian; Yabuuchi, Kiyohiro; Kimura, Akihiko

    2018-04-01

    In order to investigate the effects of oxide particles on radiation response such as hardness change and microstructural evolution, three types of oxide dispersion strengthened (ODS) ferritic steels (named Y-Ti-ODS, Y-Al-ODS and Y-Al-Zr-ODS), mostly strengthened by Y-Ti-O, Y-Al-O and Y-Zr-O dispersoids, respectively, were simultaneously irradiated with iron and helium ions at 550 °C up to a damage of 30 dpa and a corresponding helium (He) concentration of ∼3500 appm to a depth of 1000-1300 nm. A single iron ion beam irradiation was also performed for reference. Transmission electron microscopy revealed that after the dual ion irradiation helium bubbles of 2.8, 6.6 and 4.5 nm in mean diameter with the corresponding number densities of 1.1 × 1023, 2.7 × 1022 and 3.6 × 1022 m-3 were observed in Y-Ti-ODS, Y-Al-ODS and Y-Al-Zr-ODS, respectively, while no such bubbles were observed after single ion irradiation. About 80% of intragranular He bubbles were adjacent to oxide particles in the ODS ferritic steels. Although the high number density He bubbles were observed in the ODS steels, the void swelling in Y-Ti-ODS, Y-Al-ODS and Y-Al-Zr-ODS was still small and estimated to be 0.13%, 0.53% and 0.20%, respectively. The excellent swelling resistance is dominantly attributed to the high sink strength of oxide particles that depends on the morphology of particle dispersion rather than the crystal structure of the particles. In contrast, no dislocation loops were produced in any of the irradiated steels. Nanoindentation measurements showed that no irradiation hardening but softening was found in the ODS ferritic steels, which was probably due to irradiation induced dislocation recovery. The helium bubbles in high number density never contributed to the irradiation hardening of the ODS steels at these irradiation conditions.

  3. Hot isostatic pressing of single-crystal nickel-base superalloys: Mechanism of pore closure and effect on Mechanical properties

    Directory of Open Access Journals (Sweden)

    Epishin Alexander I.

    2014-01-01

    Full Text Available Pore annihilation was investigated in the single-crystal nickel-base superalloy CMSX-4. HIP tests at 1288 °C/103 MPa were interrupted at different times, then the specimens were investigated by TEM, metallography and density measurements. The kinetics of pore annihilation was determined. The pore closure mechanism was identified as plastic deformation on the octahedral slip systems. A model describing the kinetics of pore closure has been developed on the base of crystal plasticity and large strain theory. Mechanical tests with the superalloy CMSX-4 and the Ru-containing superalloy VGM4 showed, that HIP significantly increases the fatigue life at low temperatures but has no effect on creep strength.

  4. Effects of Temperature and Pressure of Hot Isostatic Pressing on the Grain Structure of Powder Metallurgy Superalloy.

    Science.gov (United States)

    Tan, Liming; He, Guoai; Liu, Feng; Li, Yunping; Jiang, Liang

    2018-02-24

    The microstructure with homogeneously distributed grains and less prior particle boundary (PPB) precipitates is always desired for powder metallurgy superalloys after hot isostatic pressing (HIPping). In this work, we studied the effects of HIPping parameters, temperature and pressure on the grain structure in PM superalloy FGH96, by means of scanning electron microscope (SEM), electron backscatter diffraction (EBSD), transmission electron microscope (TEM) and Time-of-flight secondary ion spectrometry (ToF-SIMS). It was found that temperature and pressure played different roles in controlling PPB precipitation and grain structure during HIPping, the tendency of grain coarsening under high temperature could be inhibited by increasing HIPping pressure which facilitates the recrystallization. In general, relatively high temperature and pressure of HIPping were preferred to obtain an as-HIPped superalloy FGH96 with diminished PPB precipitation and homogeneously refined grains.

  5. High Cr ODS steels R and D for high burnup fuel cladding

    International Nuclear Information System (INIS)

    Kimura, A.; Kasada, R.; Kishimoto, H.; Iwata, N.; Cho, H.-S.; Toda, N.; Yutani, K.; Ukai, S.; Fujiwara, M.

    2007-01-01

    High-performance cladding materials is essential to realize highly efficient and high-burnup operation over 150 GWd/t of so called Generation IV nuclear energy systems, such as supercritical-water-cooled reactor (SCWR) and lead-cooled fast reactor (LFR). Oxide dispersion strengthening (ODS) ferritic/ martensitic steels, which contain 9-12%Cr, show rather high resistance to neutron irradiation embrittlement and high strength at elevated temperatures. However, their corrosion resistance is not good enough in SCW and in lead at high temperatures. High-Cr ODS steels have been developed to improve corrosion resistance. An increase in Cr content an addition resulted in a drastic improvement of corrosion resistance in SCW and in lead. On the contrary, high-Cr steels often show an enhancement of aging embrittlement as well as irradiation embrittlement. Anisotropy in tensile properties is another issue. In order to overwhelm these issues, surveillance tests of the material performance have been performed for high Cr-ODS steels produced by new processing technologies. It is demonstrated that the dispersion of nono-sized oxide particles in high density is effective to attain high-performance and high-Cr ODS steels have a high potential as fuel cladding materials for SCWR and LFR with high efficiency and high burnup. (authors)

  6. Improvement of the photon flux measurement at the BGO-OD experiment

    Energy Technology Data Exchange (ETDEWEB)

    Kohl, Katrin [Physikalisches Institut, Universitaet Bonn (Germany); Collaboration: BGO-OD-Collaboration

    2016-07-01

    The BGO-OD experiment at the ELSA accelerator facility at Bonn investigates the internal reaction mechanisms of the nucleon, using an energy tagged bremsstrahlung photon beam. Absolute normalisation of the beam flux is required for cross section determination. In this talk the measurement principle is presented, and an improved method of the photon flux monitoring of the experiment is introduced.

  7. Creep in ODS copper reinforced with alumina short fibres - DRS copper

    Czech Academy of Sciences Publication Activity Database

    Kuchařová, Květa; Zhu, S. J.; Čadek, Josef

    2003-01-01

    Roč. 355, 1-2 (2003), s. 267-276 ISSN 0921-5093 R&D Projects: GA AV ČR IBS2041001 Institutional research plan: CEZ:AV0Z2041904 Keywords : Creep * ODS copper * Load transfer Subject RIV: JI - Composite Materials Impact factor: 1.365, year: 2003

  8. Evaluation of ODS-AQ stationary phase for use in capillary electrochromatography.

    Science.gov (United States)

    Djordjevic, N M; Fitzpatrick, F; Houdiere, F

    2001-04-01

    The aim of this study was to evaluate the applicability of ODS-AQ packing material as a stationary phase in capillary electrochromatography (CEC). The electroosmotic flow created on an ODS-AQ stationary phase was measured at different mobile phase compositions and at different column temperatures. It was observed that the electroosmotic flow generated in the column increased by 50% when the temperature of the system was raised from 20 degrees C to 60 degrees C, while all other conditions were kept constant. The electroosmotic flow produced by the ODS-AQ stationary phase was found to be comparable to the flow generated in a column packed with Nucleosil bare-silica material. In addition, a set of polar compounds (D-lysergic acid diethylamide derivatives) was utilized to determine the influence of temperature and mobile phase composition on their chromatographic behavior on an ODS-AQ stationary phase in a CEC mode. A linear relationship between the solute retention factor and column temperatures was seen over the temperature range studied (20 degrees C to 60 degrees C). A quadratic function was used to describe the changes in the solute retention factors with variation of acetonitrile concentration in the mobile phase.

  9. Corrosion behavior of ODS steels with several chromium contents in hot nitric acid solutions

    Science.gov (United States)

    Tanno, Takashi; Takeuchi, Masayuki; Ohtsuka, Satoshi; Kaito, Takeji

    2017-10-01

    Oxide dispersion strengthened (ODS) steel cladding tubes have been developed for fast reactors. Tempered martensitic ODS steels with 9 and 11 wt% of chromium (9Cr-, 11Cr-ODS steel) are the candidate material in research being carried out at JAEA. In this work, fundamental immersion tests and electrochemical tests of 9 to 12Cr-ODS steels were systematically conducted in various nitric acid solutions at 95 °C. The corrosion rate decreased exponentially with effective solute chromium concentration (Creff) and nitric acid concentration. Addition of vanadium (V) and ruthenium (Ru) also decreased the corrosion rate. The combination of low Creff and dilute nitric acid could not avoid the active mass dissolution during active domain at the beginning of immersion, and the corrosion rate was high. Higher Creff decreased the partial anodic current during the active domain and assisted the passivation of the surface of the steel. Concentrated nitric acid and addition of Ru and V increased partial cathodic current and shifted the corrosion potential to noble side. These effects should have prevented the active mass dissolution and decreased the corrosion rate.

  10. Evolution of oxide nanoparticles during dynamic plastic deformation of ODS steel

    DEFF Research Database (Denmark)

    Zhang, Zhenbo; Mishin, Oleg; Tao, Nairong

    2014-01-01

    The microstructure as well as the deformation behavior of oxide nanoparticles has been analyzed in the ferritic ODS steel PM2000 after compression by dynamic plastic deformation (DPD) to different strains. A dislocation cell structure forms after deformation to a strain of 1.0. DPD to a strain of 2...

  11. Temperature optimization for the separation of PAHs on micropacked LC ODS columns

    NARCIS (Netherlands)

    Chen, J.; Steenackers, D.; Sandra, P.J.F.; Sandra, P.J.F.; Devos, G.

    1993-01-01

    The effect of column temperature on the separation of the sixteen polycyclic aromatic hydrocarbons (PAHs) of mixture SRM 1647a of the US Environmental Protection Agency has been studied on different micropacked ODS columns. lsothermal temperature optimization was successfully applied for complete

  12. Deep catalytic oxidative desulfurization (ODS) of dibenzothiophene (DBT) with oxalate-based deep eutectic solvents (DESs).

    Science.gov (United States)

    Lü, Hongying; Li, Pengcheng; Deng, Changliang; Ren, Wanzhong; Wang, Shunan; Liu, Pan; Zhang, Han

    2015-07-07

    An oxalate-based DES with a tetrabutyl ammonium chloride and oxalate acid molar ratio of 1/2 (TBO1 : 2) exhibited high activity in oxidative desulfurization (ODS) of dibenzothiophene (DBT) under mild reaction conditions. It is potentially a promising and highly environmentally friendly approach for desulfurization of fuels.

  13. Temperature optimization for the separation of PAHs on micropacked LC ODS columns

    NARCIS (Netherlands)

    Chen, J.; Steenackers, D.; Medvedovici, A.; Sandra, P.J.F.

    1993-01-01

    The effect of column temperature on the separation of the sixteen polycyclic aromatic hydrocarbons (PAHs) of mixture SRM 1647a of the US Environmental Protection Agency has been studied on different micropacked ODS columns. Isothermal temperature optimization was successfully used for complete

  14. Ellunäod toovad välja "Rasputini" / Riina Mägi

    Index Scriptorium Estoniae

    Mägi, Riina, 1957-

    2008-01-01

    7. aug. Pilistvere vanas rehehoones esietenduvast Ain Saviaugu kirjutatud ja lavastatud suvetükist "Rasputin". Suvelavastuse toob välja Põltsamaa Teater Ellunäod koos professionaalsete näitlejatega. Nimiosas mängib näitlejast riigikogulane Indrek Saar

  15. Novel Interpretation of High Temperature Creep in an ODS Cu-ZrO2 Alloy

    Czech Academy of Sciences Publication Activity Database

    Čadek, Josef; Kuchařová, Květa

    2002-01-01

    Roč. 40, č. 3 (2002), s. 133-145 ISSN 0023-432X R&D Projects: GA AV ČR IBS2041001 Institutional research plan: CEZ:AV0Z2041904 Keywords : ODS Cu Alloy s * Creep Subject RIV: JI - Composite Materials Impact factor: 0.493, year: 2002

  16. A simple approach for the modeling of an ODS steel mechanical behavior in pilgering conditions

    Science.gov (United States)

    Vanegas-Márquez, E.; Mocellin, K.; Toualbi, L.; de Carlan, Y.; Logé, R. E.

    2012-01-01

    The optimization of the forming of ODS tubes is linked to the choice of an appropriated constitutive model for modeling the metal forming process. In the framework of a unified plastic constitutive theory, the strain-controlled cyclic characteristics of a ferritic ODS steel were analyzed and modeled with two different tests. The first test is a classical tension-compression test, and leads to cyclic softening at low to intermediate strain amplitudes. The second test consists in alternated uniaxial compressions along two perpendicular axes, and is selected based on the similarities with the loading path induced by the Fe-14Cr-1W-Ti ODS cladding tube pilgering process. This second test exhibits cyclic hardening at all tested strain amplitudes. Since variable strain amplitudes prevail in pilgering conditions, the parameters of the considered constitutive law were identified based on a loading sequence including strain amplitude changes. A proposed semi automated inverse analysis methodology is shown to efficiently provide optimal sets of parameters for the considered loading sequences. When compared to classical approaches, the model involves a reduced number of parameters, while keeping a good ability to capture stress changes induced by strain amplitude changes. Furthermore, the methodology only requires one test, which is an advantage when the amount of available material is limited. As two distinct sets of parameters were identified for the two considered tests, it is recommended to consider the loading path when modeling cold forming of the ODS steel.

  17. Inhibitory effect of PTD-OD-HA fusion protein on Bcr-Abl in K562 cells

    Directory of Open Access Journals (Sweden)

    Miao GAO

    2012-10-01

    Full Text Available Objective To study the transduction dynamics, location of PTD-OD-HA fusion protein and its interaction with Bcr-Abl oncoprotein in K562 cell lines, and explore the influence of PTD-OD-HA fusion protein on oligomerization and tyrosine kinase activity of Bcr-Abl. Methods PTD-OD-HA fusion protein was labeled with FITC and co-cultured with K562 cells. The transduction efficiency of labeled PTD-OD-HA at different doses and time intervals was observed under fluorescence microscope. The location of labeled PTD-OD-HA fusion protein in K562 cells was detected by confocal microscopy. The interaction of PTD-OD-HA fusion protein with Bcr-Abl oncoprotein was confirmed by coimmunoprecipitation. The phosphorylation of Bcr-Abl oncoprotein was detected by Western blotting. Results PTD-OD-HA fusion protein labeled with FITC was transduced into K562 cells in a dose- and time-dependent manner. PTD-OD-HA fusion protein was located in the cytoplasm of K562 cells and was consistent with the location of Bcr-Abl oncoprotein. The interaction of PTD-OD-HA fusion protein with Bcr-Abl oncoprotein was proved in K562 cells. This interaction could interrupt the homologous oligomerization of Bcr-Abl oncoprotein and reduce the phosphorylation of Bcr-Abl oncoprotein. Conclusion PTD-OD-HA fusion protein could be transduced into K562 cells efficiently, inhibit the oligomerization and reduce the phosphorylation of Bcr-Abl oncoprotein.

  18. The microstructure and mechanical properties of Al-containing 9Cr ODS ferritic alloy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Guangming [School of Materials Science and Engineering, University of Science and Technology, Beijing, Beijing 100083 (China); Department of Nuclear, Plasma and Radiological Engineering, University of Illinois at Urbana-Champaign, IL 61801 (United States); Zhou, Zhangjian, E-mail: zhouzhj@mater.ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology, Beijing, Beijing 100083 (China); Mo, Kun [Nuclear Engineering Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Wang, Pinghuai [Fusion Reactor & Materials Division, Southwestern Institute of Physics, Chengdu, Sichuan 610041 (China); Miao, Yinbin [Department of Nuclear, Plasma and Radiological Engineering, University of Illinois at Urbana-Champaign, IL 61801 (United States); Li, Shaofu; Wang, Man [School of Materials Science and Engineering, University of Science and Technology, Beijing, Beijing 100083 (China); Liu, Xiang [Department of Nuclear, Plasma and Radiological Engineering, University of Illinois at Urbana-Champaign, IL 61801 (United States); Gong, Mengqiang [School of Materials Science and Engineering, University of Science and Technology, Beijing, Beijing 100083 (China); Almer, Jonathan [X-ray Science Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Stubbins, James F. [Department of Nuclear, Plasma and Radiological Engineering, University of Illinois at Urbana-Champaign, IL 61801 (United States)

    2015-11-05

    In this study, a 9Cr oxide-dispersion strengthened (ODS) alloy with additional corrosion resistant element Al was fabricated by mechanical alloying (MA) and hot pressing (HP) to explore the impact of Al on the microstructure and mechanical property of a 9Cr ODS alloy. It is found that the Al completely dissolved into the Fe–Cr matrix after milling for 30 h. The minor phases in the Al-containing 9Cr ODS ferritic alloy were investigated by a high-energy X-ray, and were identified to be orthorhombic-YAlO{sub 3} (YAP), bcc-Y{sub 3}Al{sub 5}O{sub 12} (YAG), monoclinic-Al{sub 2}Y{sub 4}O{sub 9} (YAM), and hexagonal-YAlO{sub 3} (YAH). These phases were further confirmed by selected area diffraction pattern (SADP), energy dispersive spectroscopy (EDS), and high resolution transmission electron microscopy (HRTEM). In addition, their volume fractions were also calculated from the integrated intensities. According to the analysis of the particles and their formation sequences, the larger particles (greater than 100 nm) are identified as mainly YAG and Al{sub 2}O{sub 3} particles, while the particles with small size (less than 30 nm) are likely primarily YAM, YAH, and YAP particles. The yielding strength (YS) and ultimate tensile strength (UTS) at RT are 563 MPa and 744 MPa, respectively, while the YS and UTS at 700 °C are 245 MPa and 276 MPa, respectively. Although the addition Al in ODS alloys decreases the strength at RT, the values at high temperature are similar to those obtained for 9Cr ODS alloys strengthened by fine Y–Ti–O particles. - Graphical abstract: Synchrotron X-ray diffraction line profile of the 9CrAl ODS alloy; (Ferrite matrix phases, along with minor phases, orthorhombic YAlO{sub 3} (yttrium aluminum perovskite, YAP), bcc Y{sub 3}Al{sub 5}O{sub 12} (yttrium aluminum garnet, YAG), monoclinic Al{sub 2}Y{sub 4}O{sub 9} (yttrium aluminum monoclinic, YAM), and hexagonal YAlO{sub 3} (yttium aluminum hexagonal, YAH) were recognized.). - Highlights: • The

  19. FDTD modeling of thin impedance sheets

    Science.gov (United States)

    Luebbers, Raymond J.; Kunz, Karl S.

    1991-01-01

    Thin sheets of resistive or dielectric material are commonly encountered in radar cross section calculations. Analysis of such sheets is simplified by using sheet impedances. In this paper it is shown that sheet impedances can be modeled easily and accurately using Finite Difference Time Domain (FDTD) methods.

  20. Effect of solution heat treatment on the precipitation behavior and strengthening mechanisms of electron beam smelted Inconel 718 superalloy

    Energy Technology Data Exchange (ETDEWEB)

    You, Xiaogang [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116023 (China); Laboratory for New Energy Material Energetic Beam Metallurgical Equipment Engineering of Liaoning Province, Dalian 116024 (China); Tan, Yi, E-mail: tanyi@dlut.edu.cn [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116023 (China); Laboratory for New Energy Material Energetic Beam Metallurgical Equipment Engineering of Liaoning Province, Dalian 116024 (China); Shi, Shuang [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116023 (China); Laboratory for New Energy Material Energetic Beam Metallurgical Equipment Engineering of Liaoning Province, Dalian 116024 (China); Yang, Jenn-Ming [Department of Materials Science and Engineering, University of California, Los Angeles, CA 90095 (United States); Wang, Yinong [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116023 (China); Li, Jiayan; You, Qifan [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116023 (China); Laboratory for New Energy Material Energetic Beam Metallurgical Equipment Engineering of Liaoning Province, Dalian 116024 (China)

    2017-03-24

    Inconel 718 superalloy was fabricated by electron beam smelting (EBS) technique. The effect of solution heat treatment on the precipitation behavior and mechanical properties of EBS 718 superalloys were studied, the strengthening mechanisms were analyzed and related to the mechanical properties. The results indicate that the optimized microstructures can be acquired by means of EBS, which is attributed to the rapid cooling rate of approximately 280 ℃/min. The solution heat treatment shows a great impact on the microstructures, precipitation behavior and mechanical properties of EBS 718 superalloy. The γ'' phase shows an apt to precipitate at relatively lower solution temperatures followed by aging, while the γ' precipitates are prone to precipitate at higher temperatures. When solution treated at 1150 ℃, the γ' precipitates are dispersively distributed in the matrix with size and volume fraction of 8.43 nm and 21.66%, respectively, a Vickers hardness of approximately 489 HV{sub 0.1} is observed for the aged superalloy. The precipitation strengthening effect of EBS 718 superalloy could be elucidated by considering the interaction between the dislocations and γ''/γ' precipitates. The shearing of γ' is resisted by the coherency strengthening and formation of antiphase boundary (APB), which shows equal effect as weakly coupled dislocation (WCD) model. And for γ'', the strengthening effect is much more prominent with the primary strengthening mechanism of ordering. Moreover, it is interestingly found that the strengthening mechanism of stacking fault (SF) shearing coexists with APB shearing, and SF shearing plays a major role in strengthening of EBS 718 superalloy.

  1. Morphology Dependent Flow Stress in Nickel-Based Superalloys in the Multi-Scale Crystal Plasticity Framework

    Directory of Open Access Journals (Sweden)

    Shahriyar Keshavarz

    2017-11-01

    Full Text Available This paper develops a framework to obtain the flow stress of nickel-based superalloys as a function of γ-γ’ morphology. The yield strength is a major factor in the design of these alloys. This work provides additional effects of γ’ morphology in the design scope that has been adopted for the model developed by authors. In general, the two-phase γ-γ’ morphology in nickel-based superalloys can be divided into three variables including γ’ shape, γ’ volume fraction and γ’ size in the sub-grain microstructure. In order to obtain the flow stress, non-Schmid crystal plasticity constitutive models at two length scales are employed and bridged through a homogenized multi-scale framework. The multi-scale framework includes two sub-grain and homogenized grain scales. For the sub-grain scale, a size-dependent, dislocation-density-based finite element model (FEM of the representative volume element (RVE with explicit depiction of the γ-γ’ morphology is developed as a building block for the homogenization. For the next scale, an activation-energy-based crystal plasticity model is developed for the homogenized single crystal of Ni-based superalloys. The constitutive models address the thermo-mechanical behavior of nickel-based superalloys for a large temperature range and include orientation dependencies and tension-compression asymmetry. This homogenized model is used to obtain the morphology dependence on the flow stress in nickel-based superalloys and can significantly expedite crystal plasticity FE simulations in polycrystalline microstructures, as well as higher scale FE models in order to cast and design superalloys.

  2. A simple approach for the modeling of an ODS steel mechanical behavior in pilgering conditions

    International Nuclear Information System (INIS)

    Vanegas-Márquez, E.; Mocellin, K.; Toualbi, L.; Carlan, Y. de; Logé, R.E.

    2012-01-01

    Highlights: ► The mechanical behavior of an ODS steel is investigated under pilgering conditions. ► Two mechanical tests show different trends, and are described with a simple model. ► Model parameters are identified using one sample, and considering strain range changes. ► The constitutive model involves few parameters but their values are strain path dependent. ► One identified set of parameters would be appropriate for FEM modeling of pilgering. - Abstract: The optimization of the forming of ODS tubes is linked to the choice of an appropriated constitutive model for modeling the metal forming process. In the framework of a unified plastic constitutive theory, the strain-controlled cyclic characteristics of a ferritic ODS steel were analyzed and modeled with two different tests. The first test is a classical tension–compression test, and leads to cyclic softening at low to intermediate strain amplitudes. The second test consists in alternated uniaxial compressions along two perpendicular axes, and is selected based on the similarities with the loading path induced by the Fe–14Cr–1W–Ti ODS cladding tube pilgering process. This second test exhibits cyclic hardening at all tested strain amplitudes. Since variable strain amplitudes prevail in pilgering conditions, the parameters of the considered constitutive law were identified based on a loading sequence including strain amplitude changes. A proposed semi automated inverse analysis methodology is shown to efficiently provide optimal sets of parameters for the considered loading sequences. When compared to classical approaches, the model involves a reduced number of parameters, while keeping a good ability to capture stress changes induced by strain amplitude changes. Furthermore, the methodology only requires one test, which is an advantage when the amount of available material is limited. As two distinct sets of parameters were identified for the two considered tests, it is recommended to

  3. Mechanosynthesis of A Ferritic ODS (Oxide Dispersion Strengthened) Steel Containing 14% Chromium and Its Characterization

    Science.gov (United States)

    Rivai, A. K.; Dimyati, A.; Adi, W. A.

    2017-05-01

    One of the advanced materials for application at high temperatures which is aggressively developed in the world is ODS (Oxide Dispersion strengthened) steel. ODS ferritic steels are one of the candidate materials for future nuclear reactors in the world (Generation IV reactors) because it is able to be used in the reactor above 600 °C. ODS ferritic steels have also been developed for the interconnect material of SOFC (Solid Oxide Fuel Cell) which will be exposed to about 800 °C of temperature. The steel is strengthened by dispersing homogeneously of oxide particles (ceramic) in nano-meter sized in the matrix of the steel. Synthesis of a ferritic ODS steel by dispersion of nano-particles of yttrium oxide (yttria: Y2O3) as the dispersion particles, and containing high-chromium i.e. 14% has been conducted. Synthesis of the ODS steels was done mechanically (mechanosynthesis) using HEM (High Energy ball Milling) technique for 40 and 100 hours. The resulted samples were characterized using SEM-EDS (Scanning Electron Microscope-Energy Dispersive Spectroscope), and XRD (X-ray diffraction) to analyze the microstructure characteristics. The results showed that the crystal grains of the sample with 100 hours milling time was much smaller than the sample with 40 hours milling time, and some amount of alloy was formed during the milling process even for 40 hours milling time. Furthermore, the structure analysis revealed that some amount of iron atom substituted by a slight amount of chromium atom as a solid solution. The quantitative analysis showed that the phase mostly consisted of FeCr solid-solution with the structure was BCC (body-centered cubic).

  4. High-cycle fatigue behavior of Co-based superalloy 9CrCo at elevated temperatures

    OpenAIRE

    Wan, Aoshuang; Xiong, Junjiang; Lyu, Zhiyang; Li, Kuang; Du, Yisen; Chen, Kejiao; Man, Ziyu

    2016-01-01

    A modified model is developed to characterize and evaluate high-cycle fatigue behavior of Co-based superalloy 9CrCo at elevated temperatures by considering the stress ratio effect. The model is informed by the relationship surface between maximum nominal stress, stress ratio and fatigue life. New formulae are derived to deal with the test data for estimating the parameters of the proposed model. Fatigue tests are performed on Co-based superalloy 9CrCo subjected to constant amplitude loading a...

  5. Dendritic coarsening of γ' phase in a directionally solidified superalloy during 24,000 h of exposure at 1173 K

    International Nuclear Information System (INIS)

    Li, H.; Wang, L.; Lou, L.H.

    2010-01-01

    Dendritic coarsening of γ' was investigated in a directionally solidified Ni-base superalloy during exposure at 1173 K for 24,000 h. Chemical homogeneity along different directions and residual internal strain in the experimental superalloy were measured by electronic probe microanalysis (EPMA) and electron back-scattered diffraction (EBSD) technique. It was indicated that the gradient of element distribution was anisotropic and the inner strain between dendrite core and interdendritic regions was different even after 24,000 h of exposure at 1173 K, which influenced the kinetics for the dendrite coarsening of γ' phase.

  6. The effects of ruthenium on the phase stability of fourth generation Ni-base single crystal superalloys

    International Nuclear Information System (INIS)

    Sato, Atsushi; Harada, Hiroshi; Yokokawa, Tadaharu; Murakumo, Takao; Koizumi, Yutaka; Kobayashi, Toshiharu; Imai, Hachiro

    2006-01-01

    The formation of topologically close-packed (TCP) phases in nickel-base single crystal superalloys causes considerable degradation of the mechanical properties. It has recently been found that platinum-group metals can be effective in controlling the precipitation of such phases, and this extent of precipitation control requires further investigation. This study compares Ru-containing and non-Ru-containing single crystal superalloys. Scanning electron microscopy microstructural observations showed that the rate of TCP phase precipitations decreased through Ru addition. Transmission electron microscopy microstructural observations showed that the P phase, one of the TCP phases, was eliminated through the addition of Ru. The occurrence of this phenomenon will be discussed

  7. On Jovian plasma sheet structure

    International Nuclear Information System (INIS)

    Khurana, K.K.; Kivelson, M.G.

    1989-01-01

    The authors evaluate several models of Jovian plasma sheet structure by determining how well they organize several aspects of the observed Voyager 2 magnetic field characteristics as a function of Jovicentric radial distance. It is shown that in the local time sector of the Voyager 2 outbound pass (near 0300 LT) the published hinged-magnetodisc models with wave (i.e., models corrected for finite wave velocity effects) are more successful than the published magnetic anomaly model in predicting locations of current sheet crossings. They also consider the boundary between the plasma sheet and the magnetotail lobe which is expected to vary slowly with radial distance. They use this boundary location as a further test of the models of the magnetotail. They show that the compressional MHD waves have much smaller amplitude in the lobes than in the plasma sheet and use this criterion to refine the identification of the plasma-sheet-lobe boundary. When the locations of crossings into and out of the lobes are examined, it becomes evident that the magnetic-anomaly model yields a flaring plasma sheet with a halfwidth of ∼ 3 R J at a radial distance of 20 R J and ∼ 12 R J at a radial distance of 100 R J . The hinged-magnetodisc models with wave, on the other hand, predict a halfwidth of ∼ 3.5 R J independent of distance beyond 20 R J . New optimized versions of the two models locate both the current sheet crossings and lobe encounters equally successfully. The optimized hinged-magnetodisc model suggests that the wave velocity decreases with increasing radial distance. The optimized magnetic anomaly model yields lower velocity contrast than the model of Vasyliunas and Dessler (1981)

  8. Automobile sheet metal part production with incremental sheet forming

    Directory of Open Access Journals (Sweden)

    İsmail DURGUN

    2016-02-01

    Full Text Available Nowadays, effect of global warming is increasing drastically so it leads to increased interest on energy efficiency and sustainable production methods. As a result of adverse conditions, national and international project platforms, OEMs (Original Equipment Manufacturers, SMEs (Small and Mid-size Manufacturers perform many studies or improve existing methodologies in scope of advanced manufacturing techniques. In this study, advanced manufacturing and sustainable production method "Incremental Sheet Metal Forming (ISF" was used for sheet metal forming process. A vehicle fender was manufactured with or without die by using different toolpath strategies and die sets. At the end of the study, Results have been investigated under the influence of method and parameters used.Keywords: Template incremental sheet metal, Metal forming

  9. The effects of Re addition to the nanostructure of a Ni-Cr-Al model superalloy

    International Nuclear Information System (INIS)

    Yoon, K.E.; Seidman, D.N.; Noebe, R.D.

    2004-01-01

    Full text: The refractory elements, such as W, Mo, Ta, and Re, have been at the center of focus since the late 1970s for the development of single-crystal turbine-blades, and they have improved significantly the high-temperature properties of Ni-based superalloys. The optimum mechanical properties and operating temperature of single-crystal blades are achieved by increasing the total amounts of refractory elements. In spite of the improvement of mechanical properties of Ni-based superalloys utilizing the addition of refractory elements, their effects on the microstructure of superalloys are mostly unidentified at the subnano- to nanoscale. Rhenium (2 at.%) was added to a model ternary Ni-8.5 at.% Cr-10 at.% Al superalloy to study its effects on the temporal evolution. The temporal evolution of γ' (L1 2 ) precipitates in a Ni-Cr-AI-Re FCC alloy, aged at 1073 K from 0.25 to 264 h, is investigated by transmission-electron and three-dimensional atom-probe (3DAP) microscopies. The coarsening kinetics of γ' precipitates is investigated by measuring the mean radius, number density of precipitates and matrix supersaturation, and compared with Umantsev-Olson's (UO) coarsening theory for multicomponent alloys. The coarsening experiments do not agree with the time dependencies prediction of UO theory. The cluster-diffusion-coagulation mechanism is involved in coarsening, as well as evaporation-condenzation mechanism, and is suggested to generate discrepancy between the experiments and theory. The addition of Re reduces the lattices parameter misfit between the matrix and precipitates. Therefore, unlike other Ni-based superalloys, this Ni-Cr-AI-Re alloy does not undergo the sphere-to-cube morphological transition and maintains the spheroidal morphology of the γ' precipitates for extended aging times. In addition, the γ' precipitates do not align along [100] direction, even at the longest aging time of 264 h. Contrary to a commercial superalloy Rene N6, significant Re

  10. OD in North American Schools: A Scandinavian View, with Comments by Matthew Miles and Michael Fullan. Uppsala Reports on Education, No. 20.

    Science.gov (United States)

    Berg, Gunnar

    This report discusses the structural conditions under which organizational development (OD), as employed in the school systems of the United States and Canada, is more or less applicable to schools. The first section (chapters 1-6) reviews papers and books, concerning either OD in general or the ways in which the ideas of OD have been used in the…

  11. The Use of Orientation/Decision/Do/Discuss/Reflect (OD3R) Method to Increase Critical Thinking Skill and Practical Skill in Biochemistry Learning

    Science.gov (United States)

    Anwar, Yunita Arian Sani; Senam, Senam; Laksono, Endang W.

    2018-01-01

    We have developed an OD3R method that can be applied on Biochemistry learning. This OD3R consists of 5 phases: orientation, decision, do, discuss, and reflect to connect lessons in the class with practice in the laboratory. Implementation of OD3R method was done in 2 universities in Yogyakarta to increase critical thinking skill and practical…

  12. IE Information Notice No. 85-64: BBC Brown Boveri low-voltage K-line circuit breakers, with deficient overcurrent trip devices models OD-4 and 5

    International Nuclear Information System (INIS)

    Jordan, E.L.

    1992-01-01

    On May 13, 1985, BBC Brown Boveri Inc. (BBC) made a 10 CFR Part 21 report to the NRC concerning a deficiency in the Models OD-4 and OD-5 overcurrent trip devices installed on K-line circuit breakers. The affected breakers were manufactured by BBC from October 1983 to March 1985 and may have incorrect short time delay band levers (links) installed in electromechanical overcurrent trip device models OD-4 and OD-5. The incorrect link could limit the travel of the short time armature and cause the short time element to be inoperative in the maximum (MAX) band. The May 13, 1985, report recommended that all K-line circuit breakers with the OD-4 and OD-5 overcurrent trip devices and any spare OD-4 and OD-5 overcurrent trip devices that were manufactured between October 1983 and March 1985, be inspected for an incorrect short time delay band link. Licensees known by BBC to have purchased K-line breakers or spare OD-4 or OD-5 overcurrent trip devices were notified of the possible defect and instructions provided for their inspection. Enclosed is a list of utilities and related facilities that were notified by BBC. However, BBC advised the NRC that there is a possibility that other utilities could be using K-line circuit breakers with the suspect OD-4 and OD-5 overcurrent trip devices. Therefore, all licensees are being notified of this possible defect

  13. Uranium mining sites - Thematic sheets

    International Nuclear Information System (INIS)

    2009-01-01

    A first sheet proposes comments, data and key numbers about uranium extraction in France: general overview of uranium mining sites, status of waste rock and tailings after exploitation, site rehabilitation. The second sheet addresses the sources of exposure to ionizing radiations due to ancient uranium mining sites: discussion on the identification of these sources associated with these sites, properly due to mining activities or to tailings, or due to the transfer of radioactive substances towards water and to the contamination of sediments, description of the practice and assessment of radiological control of mining sites. A third sheet addresses the radiological exposure of public to waste rocks, and the dose assessment according to exposure scenarios: main exposure ways to be considered, studied exposure scenarios (passage on backfilled path and grounds, stay in buildings built on waste rocks, keeping mineralogical samples at home). The fourth sheet addresses research programmes of the IRSN on uranium and radon: epidemiological studies (performed on mine workers; on French and on European cohorts, French and European studies on the risk of lung cancer associated with radon in housing), study of the biological effects of chronic exposures. The last sheet addresses studies and expertises performed by the IRSN on ancient uranium mining sites in France: studies commissioned by public authorities, radioactivity control studies performed by the IRSN about mining sites, participation of the IRSN to actions to promote openness to civil society

  14. Effect of Crystal Orientation on Fatigue Failure of Single Crystal Nickel Base Turbine Blade Superalloys

    Science.gov (United States)

    Arakere, Nagaraj K.; Swanson, Gregory R.

    2000-01-01

    High Cycle Fatigue (HCF) induced failures in aircraft gas-turbine engines is a pervasive problem affecting a wide range of components and materials. HCF is currently the primary cause of component failures in gas turbine aircraft engines. Turbine blades in high performance aircraft and rocket engines are increasingly being made of single crystal nickel superalloys. Single-crystal Nickel-base superalloys were developed to provide superior creep, stress rupture, melt resistance and thermomechanical fatigue capabilities over polycrystalline alloys previously used in the production of turbine blades and vanes. Currently the most widely used single crystal turbine blade superalloys are PWA 1480/1493 and PWA 1484. These alloys play an important role in commercial, military and space propulsion systems. PWA1493, identical to PWA1480, but with tighter chemical constituent control, is used in the NASA SSME (Space Shuttle Main Engine) alternate turbopump, a liquid hydrogen fueled rocket engine. Objectives for this paper are motivated by the need for developing failure criteria and fatigue life evaluation procedures for high temperature single crystal components, using available fatigue data and finite element modeling of turbine blades. Using the FE (finite element) stress analysis results and the fatigue life relations developed, the effect of variation of primary and secondary crystal orientations on life is determined, at critical blade locations. The most advantageous crystal orientation for a given blade design is determined. Results presented demonstrates that control of secondary and primary crystallographic orientation has the potential to optimize blade design by increasing its resistance to fatigue crack growth without adding additional weight or cost.

  15. Thermal evolution behavior of carbides and γ′ precipitates in FGH96 superalloy powder

    International Nuclear Information System (INIS)

    Zhang Lin; Liu Hengsan; He Xinbo; Rafi-ud-din; Qu Xuanhui; Qin Mingli; Li Zhou; Zhang Guoqing

    2012-01-01

    The characteristics of rapidly solidified FGH96 superalloy powder and the thermal evolution behavior of carbides and γ′ precipitates within powder particles were investigated. It was observed that the reduction of powder size and the increase of cooling rate had transformed the solidification morphologies of atomized powder from dendrite in major to cellular structure. The secondary dendritic spacing was measured to be 1.02–2.55 μm and the corresponding cooling rates were estimated to be in the range of 1.4 × 10 4 –4.7 × 10 5 K·s −1 . An increase in the annealing temperature had rendered the phase transformation of carbides evolving from non-equilibrium MC′ carbides to intermediate transition stage of M 23 C 6 carbides, and finally to thermodynamically stable MC carbides. The superfine γ′ precipitates were formed at the dendritic boundaries of rapidly solidified superalloy powder. The coalescence, growth, and homogenization of γ' precipitates occurred with increasing annealing temperature. With decreasing cooling rate from 650 °C·K −1 to 5 °C·K −1 , the morphological development of γ′ precipitates had been shown to proceed from spheroidal to cuboidal and finally to solid state dendrites. Meanwhile, a shift had been observed from dendritic morphology to recrystallized structure between 900 °C and 1050 °C. Moreover, accelerated evolution of carbides and γ' precipitates had been facilitated by the formation of new grain boundaries which provide fast diffusion path for atomic elements. - Highlights: ► Microstructural characteristic of FGH96 superalloy powder was investigated. ► The relation between microstructure, particle size, and cooling rate was studied. ► Thermal evolution behavior of γ′ and carbides in loose FGH96 powder was studied.

  16. Formation and Dissolution of gamma ' Precipitates in IN792 Superalloy at Elevated Temperatures

    Czech Academy of Sciences Publication Activity Database

    Strunz, Pavel; Petrenec, Martin; Polák, Jaroslav; Gasser, U.; Farkas, G.

    2016-01-01

    Roč. 6, č. 2 (2016), č. článku 37. ISSN 2075-4701 R&D Projects: GA ČR GB14-36566G; GA MŠk(CZ) LM2011019 EU Projects: European Commission(XE) 283883 - NMI3-II Institutional support: RVO:61389005 ; RVO:68081723 Keywords : metals * high temperature alloys * superalloy * precipitation * neutron scattering * in-situ neutron diffraction * small-angle neutron scattering Subject RIV: BM - Solid Matter Physics ; Magnetism; JL - Materials Fatigue, Friction Mechanics (UFM-A) Impact factor: 1.984, year: 2016

  17. Microstructural investigation of thermally aged nickel-based superalloy 718Plus

    International Nuclear Information System (INIS)

    Whitmore, Lawrence; Ahmadi, Mohammad Reza; Stockinger, Martin; Povoden-Karadeniz, Erwin; Kozeschnik, Ernst; Leitner, Harald

    2014-01-01

    The effects of thermal aging upon the nickel-based 718Plus superalloy are investigated and modelled. Yield strength and micro-hardness measurements are made after solution annealing and after aging at 788 °C for 4 h. In order to explain the differences in strength and hardness, a detailed investigation of the microstructure is performed using transmission electron microscopy. The size and phase fraction of the γ′ precipitates are measured and related to the measured hardness and yield strength using a theoretical model of precipitation strengthening based on the shearing of precipitates in terms of coherency strengthening and the formation of an antiphase boundary

  18. Homogenization Kinetics of a Nickel-based Superalloy Produced by Powder Bed Fusion Laser Sintering.

    Science.gov (United States)

    Zhang, Fan; Levine, Lyle E; Allen, Andrew J; Campbell, Carelyn E; Lass, Eric A; Cheruvathur, Sudha; Stoudt, Mark R; Williams, Maureen E; Idell, Yaakov

    2017-04-01

    Additively manufactured (AM) metal components often exhibit fine dendritic microstructures and elemental segregation due to the initial rapid solidification and subsequent melting and cooling during the build process, which without homogenization would adversely affect materials performance. In this letter, we report in situ observation of the homogenization kinetics of an AM nickel-based superalloy using synchrotron small angle X-ray scattering. The identified kinetic time scale is in good agreement with thermodynamic diffusion simulation predictions using microstructural dimensions acquired by ex situ scanning electron microscopy. These findings could serve as a recipe for predicting, observing, and validating homogenization treatments in AM materials.

  19. Development of a Ni-based superalloy with cellular structure and interconnected micro porosity

    International Nuclear Information System (INIS)

    Bernabe, A.; Lopez, E.; Gil-Sevillano, J.

    1998-01-01

    A cellular metallic material with interconnected porosity of controlled size of an order of 10 μm has been developed by electrochemical dissolution of tungsten grains in a W-Ni-Fe heavy alloy. The nickel superalloy with sponge structure and high surface/volume ratio can also be processed recycling chips from heavy metal machining (Patent number p9700191, 1997). Applications for the new materials could be found as support for catalysts, high temperature filters for corrosive fluids, burners, etc. (Author) 10 refs

  20. Precipitate Contribution to the Acoustic Nonlinearity in Nickel-Based Superalloy

    Institute of Scientific and Technical Information of China (English)

    Chung-Seok KIM; Cliff J.LISSENDEN

    2009-01-01

    The influence of γ' precipitate on the acoustic nonlinearity is investigated for a nickel-based superalloy,which is subjected to creep deformation.During creep deformation,the cuboidal γ' precipitate is preferentially coarsened in a direction perpendicular to the applied stress axis.The length and shape factor of the γ' precipitate increase with creep time.The increase of relative acoustic nonlinearity with increasing fraction of creep life is discussed in relation to the rafting of γ' precipitate,which is closely related to the scattering and distortion of the acoustic wave.

  1. Mesoscale modeling and simulation of microstructure evolution during dynamic recrystallization of a Ni-based superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Fei [University of Nottingham, Department of Mechanical, Materials and Manufacturing Engineering, Nottingham (United Kingdom); Shanghai Jiao Tong University, Institute of Forming Technology and Equipment, Shanghai (China); Cui, Zhenshan [Shanghai Jiao Tong University, Institute of Forming Technology and Equipment, Shanghai (China); Ou, Hengan [University of Nottingham, Department of Mechanical, Materials and Manufacturing Engineering, Nottingham (United Kingdom); Long, Hui [University of Sheffield, Department of Mechanical Engineering, Sheffield (United Kingdom)

    2016-10-15

    Microstructural evolution and plastic flow characteristics of a Ni-based superalloy were investigated using a simulative model that couples the basic metallurgical principle of dynamic recrystallization (DRX) with the two-dimensional (2D) cellular automaton (CA). Variation of dislocation density with local strain of deformation is considered for accurate determination of the microstructural evolution during DRX. The grain topography, the grain size and the recrystallized fraction can be well predicted by using the developed CA model, which enables to the establishment of the relationship between the flow stress, dislocation density, recrystallized fraction volume, recrystallized grain size and the thermomechanical parameters. (orig.)

  2. Synergistic erosion/corrosion of superalloys in PFB coal combustor effluent

    Science.gov (United States)

    Benford, S. M.; Zellars, G. R.; Lowell, C. E.

    1981-01-01

    Two Ni-based superalloys were exposed to the high velocity effluent of a pressurized fluidized bed coal combustor. Targets were 15 cm diameter rotors operating at 40,000 rpm and small flat plate specimens. Above an erosion rate threshold, the targets were eroded to bare metal. The presence of accelerated oxidation at lower erosion rates suggests erosion/corrosion synergism. Various mechanisms which may contribute to the observed oxide growth enhancement include erosive removal of protective oxide layers, oxide and subsurface cracking, and chemical interaction with sulfur in the gas and deposits through damaged surface layers.

  3. Creep-rupture behavior of iron superalloys in high-pressure hydrogen

    Science.gov (United States)

    Bhattacharyya, S.; Peterman, W.

    1984-01-01

    The creep-rupture properties of five iron-base and one cobalt-base high temperature alloys were investigated to assess the feasibility of using the alloys as construction materials in a Stirling engine. The alloys were heat treated and hardness measurements were taken. Typical microstructures of the alloys are shown. The creep-rupture properties of the alloys were determined at 760 and 815 C in 15.0 MPa H2 for 200 to 1000 hours. Plots of rupture life versus stress for the six superalloys are presented along with creep strain-time plots.

  4. Phase transformation and liquid density redistribution during solidification of Ni-based superalloy Inconel 718

    Directory of Open Access Journals (Sweden)

    Wang Ling

    2012-08-01

    Full Text Available The influences of chemical segregation and phase transformation on liquid density variation during solidification of Ni-based supperalloy Inconel 718 were investigated using SEM and EDS. It was found that significant segregation in liquid prompts high Nb phase to precipitate directly from liquid, which results in the redistribution of alloy elements and liquid density in their vicinity. The term “inter-precipitate liquid density” is therefore proposed and this concept should be applied to determine the solidification behavior of superalloy Inconel 718.

  5. Superior creep strength of a nickel-based superalloy produced by selective laser melting

    Energy Technology Data Exchange (ETDEWEB)

    Pröbstle, M., E-mail: martin.proebstle@fau.de [Department of Materials Science & Engineering Institute I, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstraße 5, D-91058 Erlangen (Germany); Neumeier, S.; Hopfenmüller, J.; Freund, L.P. [Department of Materials Science & Engineering Institute I, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstraße 5, D-91058 Erlangen (Germany); Niendorf, T. [Institut für Werkstofftechnik (Materials Engineering), Universität Kassel, Mönchebergstr. 3, D-34125 Kassel (Germany); Schwarze, D. [SLM Solutions GmbH, Roggenhorster Straße 9c, D-23556 Lübeck (Germany); Göken, M. [Department of Materials Science & Engineering Institute I, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstraße 5, D-91058 Erlangen (Germany)

    2016-09-30

    The creep properties of a polycrystalline nickel-based superalloy produced via selective laser melting were investigated in this study. All heat treatment conditions of the additively manufactured material show superior creep strength compared to conventional cast and wrought material. The process leads to a microstructure with fine subgrains. In comparison to conventional wrought material no Niobium rich δ phase is necessary to control the grain size and thus more Niobium is available for precipitation hardening and solid solution strengthening resulting in improved creep strength.

  6. Ir-based refractory superalloys by pulse electric current sintering (PECS) process (II prealloyed powder)

    Science.gov (United States)

    Huang, C.; Yamabe-Mitarai, Y.; Harada, H.

    2002-02-01

    Five prealloyed powder samples prepared from binary Ir-based refractory superalloys were sintered at 1800 °C for 4 h by Pulse Electric Current Sintering (PECS). No metal loss was observed during sintering. The relative densities of the sintered specimens all exceeded 90% T.D. The best one was Ir-13% Hf with the density of 97.82% T.D. Phases detected in sintered samples were in accordance with the phase diagram as expected. Fractured surfaces were observed in two samples (Ir-13% Hf and Ir-15% Zr). Some improvements obtained by using prealloyed powders instead of elemental powders, which were investigated in the previous studies, were presented.

  7. Inhomogeneous dislocation structure in fatigued INCONEL 713 LC superalloy at room and elevated temperatures

    International Nuclear Information System (INIS)

    Petrenec, Martin; Obrtlik, Karel; Polak, Jaroslav

    2005-01-01

    The dislocations arrangement was studied using transmission electron microscopy in specimens of polycrystalline INCONEL 713 LC superalloy cyclically strained up to failure with constant total strain amplitudes at temperatures 300, 773, 973 and 1073 K. Planar dislocation arrangements in the form of bands parallel to the {1 1 1} planes were observed in specimens cycled at all the temperatures. The bands showed up as thin slabs of high dislocation density cutting both the γ channels and γ' precipitates. Ladder-like bands were observed at room temperature

  8. Cyclic plastic response of nickel-based superalloy at room and at elevated temperatures

    International Nuclear Information System (INIS)

    Polak, Jaroslav; Petrenec, Martin; Chlupova, Alice; Tobias, Jiri; Petras, Roman

    2015-01-01

    Nickel-based cast IN 738LC superalloy has been cycled at increasing strain amplitudes at room temperature and at 800 C. Hysteresis loops were analyzed using general statistical theory of the hysteresis loop. Dislocation structures of specimens cycled at these two temperatures were studied. They revealed localization of the cyclic plastic strain in the thin bands which are rich in dislocations. The analysis of the loop shapes yields effective stresses of the matrix and of the precipitates and the probability density function of the critical internal stresses at both temperatures. It allows to find the sources of the high cyclic stress.

  9. Nondestructive Induced Residual Stress Assessment in Superalloy Turbine Engine Components Using Induced Positron Annihilation (IPA)

    International Nuclear Information System (INIS)

    Rideout, C. A.; Ritchie, S. J.; Denison, A.

    2007-01-01

    Induced Positron Analysis (IPA) has demonstrated the ability to nondestructively quantify shot peening/surface treatments and relaxation effects in single crystal superalloys, steels, titanium and aluminum with a single measurement as part of a National Science Foundation SBIR program and in projects with commercial companies. IPA measurement of surface treatment effects provides a demonstrated ability to quantitatively measure initial treatment effectiveness along with the effect of operationally induced changes over the life of the treated component. Use of IPA to nondestructively quantify surface and subsurface residual stresses in turbine engine materials and components will lead to improvements in current engineering designs and maintenance procedures

  10. Computational Design of Creep-Resistant Alloys and Experimental Validation in Ferritic Superalloys

    Energy Technology Data Exchange (ETDEWEB)

    Liaw, Peter

    2014-12-31

    A new class of ferritic superalloys containing B2-type zones inside parent L21-type precipitates in a disordered solid-solution matrix, also known as a hierarchical-precipitate strengthened ferritic alloy (HPSFA), has been developed for high-temperature structural applications in fossil-energy power plants. These alloys were designed by the addition of the Ti element into a previously-studied NiAl-strengthened ferritic alloy (denoted as FBB8 in this study). In the present research, systematic investigations, including advanced experimental techniques, first-principles calculations, and numerical simulations, have been integrated and conducted to characterize the complex microstructures and excellent creep resistance of HPSFAs. The experimental techniques include transmission-electron microscopy, scanningtransmission- electron microscopy, neutron diffraction, and atom-probe tomography, which provide detailed microstructural information of HPSFAs. Systematic tension/compression creep tests revealed that HPSFAs exhibit the superior creep resistance, compared with the FBB8 and conventional ferritic steels (i.e., the creep rates of HPSFAs are about 4 orders of magnitude slower than the FBB8 and conventional ferritic steels.) First-principles calculations include interfacial free energies, anti-phase boundary (APB) free energies, elastic constants, and impurity diffusivities in Fe. Combined with kinetic Monte- Carlo simulations of interdiffusion coefficients, and the integration of computational thermodynamics and kinetics, these calculations provide great understanding of thermodynamic and mechanical properties of HPSFAs. In addition to the systematic experimental approach and first-principles calculations, a series of numerical tools and algorithms, which assist in the optimization of creep properties of ferritic superalloys, are utilized and developed. These numerical simulation results are compared with the available experimental data and previous first

  11. Investigation of grain competitive growth during directional solidification of single-crystal nickel-based superalloys

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Xinbao [National Energy R and D Center of Clean and High-Efficiency Fossil-Fired Power Generation Technology, Xi' an Thermal Power Research Institute Co. Ltd., Xi' an (China); Northwestern Polytechnical University, State Key Laboratory of Solidification Processing, Xi' an (China); Liu, Lin; Zhang, Jun [Northwestern Polytechnical University, State Key Laboratory of Solidification Processing, Xi' an (China)

    2015-08-15

    Grain competitive growth of nickel-based single-crystal superalloys during directional solidification was investigated. A detailed characterization of bi-crystals' competitive growth was performed to explore the competitive grain evolution. It was found that high withdrawal rate improved the efficiency of grain competitive growth. The overgrowth rate was increased when the misorientation increased. Four patterns of grain competitive growth with differently oriented dispositions were characterized. The results indicated that the positive branching of the dendrites played a significant role in the competitive growth process. The effect of crystal orientation and heat flow on the competitive growth can be attributed to the blocking mechanism between the adjacent grains. (orig.)

  12. Creep, Fatigue and Environmental Interactions and Their Effect on Crack Growth in Superalloys

    Science.gov (United States)

    Telesman, J.; Gabb, T. P.; Ghosn, L. J.; Smith, T.

    2017-01-01

    Complex interactions of creep/fatigue/environment control dwell fatigue crack growth (DFCG) in superalloys. Crack tip stress relaxation during dwells significantly changes the crack driving force and influence DFCG. Linear Elastic Fracture Mechanics, Kmax, parameter unsuitable for correlating DFCG behavior due to extensive visco-plastic deformation. Magnitude of remaining crack tip axial stresses controls DFCG resistance due to the brittle-intergranular nature of the crack growth process. Proposed a new empirical parameter, Ksrf, which incorporates visco-plastic evolution of the magnitude of remaining crack tip stresses. Previous work performed at 704C, extend the work to 760C.

  13. Fabrication and characterization of reference 9Cr and 12Cr-ODS low activation ferritic/martensitic steels

    Energy Technology Data Exchange (ETDEWEB)

    Muroga, T., E-mail: muroga@nifs.ac.jp [National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292 (Japan); Nagasaka, T. [National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292 (Japan); Li, Y.; Abe, H. [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Ukai, S. [Graduate School of Engineering, Hokkaido University, N13, W8, Kita-ku, Sapporo 060-8628 (Japan); Kimura, A. [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Okuda, T. [Kobelco Research Institute, 1-5-5 Takatsukadai, Nishi-ku, Kobe, Hyogo 651-2271 (Japan)

    2014-10-15

    For the purpose of arranging reference alloys available for various characterization efforts by Japanese fusion research groups, fabrication of reference 9Cr and 12Cr-ODS steels have been carried out with similar manufacturing processes followed by various characterizations. The fabrication proceeded with powder mixing, MA, encapsulation into mild steel cases, hot extrusion and hot forging, followed by final heat treatments. Each alloy was extruded into three bars. The characterization included chemical composition analysis, SEM and TEM microstructural observations, hardness tests, tensile tests at RT and 973 K, and relatively short-term thermal creep tests at 973 K. Room temperature hardness for 9Cr-ODS was larger than 12Cr-ODS, the former showing large increase when annealing temperature exceeded 1200 K and the latter showing no significant change with annealing temperature. Tensile strength of 9Cr-ODS was significantly larger than that of 12Cr-ODS at RT but comparable at 973 K. 9Cr-ODS showed longer and shorter creep rupture time than 12Cr-ODS at high and low stress levels, respectively. The mechanism of the difference in creep properties of the two alloys was discussed.

  14. Root-growth-inhibiting sheet

    Science.gov (United States)

    Burton, F.G.; Cataldo, D.A.; Cline, J.F.; Skiens, W.E.; Van Voris, P.

    1993-01-26

    In accordance with this invention, a porous sheet material is provided at intervals with bodies of a polymer which contain a 2,6-dinitroaniline. The sheet material is made porous to permit free passage of water. It may be either a perforated sheet or a woven or non-woven textile material. A particularly desirable embodiment is a non-woven fabric of non-biodegradable material. This type of material is known as a geotextile'' and is used for weed control, prevention of erosion on slopes, and other landscaping purposes. In order to obtain a root repelling property, a dinitroaniline is blended with a polymer which is attached to the geotextile or other porous material.

  15. Optimal swimming of a sheet.

    Science.gov (United States)

    Montenegro-Johnson, Thomas D; Lauga, Eric

    2014-06-01

    Propulsion at microscopic scales is often achieved through propagating traveling waves along hairlike organelles called flagella. Taylor's two-dimensional swimming sheet model is frequently used to provide insight into problems of flagellar propulsion. We derive numerically the large-amplitude wave form of the two-dimensional swimming sheet that yields optimum hydrodynamic efficiency: the ratio of the squared swimming speed to the rate-of-working of the sheet against the fluid. Using the boundary element method, we show that the optimal wave form is a front-back symmetric regularized cusp that is 25% more efficient than the optimal sine wave. This optimal two-dimensional shape is smooth, qualitatively different from the kinked form of Lighthill's optimal three-dimensional flagellum, not predicted by small-amplitude theory, and different from the smooth circular-arc-like shape of active elastic filaments.

  16. Root-growth-inhibiting sheet

    Science.gov (United States)

    Burton, Frederick G.; Cataldo, Dominic A.; Cline, John F.; Skiens, W. Eugene; Van Voris, Peter

    1993-01-01

    In accordance with this invention, a porous sheet material is provided at intervals with bodies of a polymer which contain a 2,6-dinitroaniline. The sheet material is made porous to permit free passage of water. It may be either a perforated sheet or a woven or non-woven textile material. A particularly desirable embodiment is a non-woven fabric of non-biodegradable material. This type of material is known as a "geotextile" and is used for weed control, prevention of erosion on slopes, and other landscaping purposes. In order to obtain a root repelling property, a dinitroaniline is blended with a polymer which is attached to the geotextile or other porous material.

  17. Fast high-temperature consolidation of Oxide-Dispersion Strengthened (ODS) steels: process, microstructure, precipitation, properties

    International Nuclear Information System (INIS)

    Boulnat, Xavier

    2014-01-01

    This work aims to lighten the understanding of the behavior of a class of metallic materials called Oxide-Dispersion Strengthened (ODS) ferritic steels. ODS steels are produced by powder metallurgy with various steps including atomization, mechanical alloying and high-temperature consolidation. The consolidation involves the formation of nanoparticles in the steel and various evolutions of the microstructure of the material that are not fully understood. In this thesis, a novel consolidation technique assisted by electric field called 'Spark Plasma Sintering' (SPS) or 'Field-Assisted Sintering Technique' (FAST) was assessed. Excellent mechanical properties were obtained by SPS, comparable to those of conventional hot isostatic pressed (HIP) materials but with much shorter processing time. Also, a broad range of microstructures and thus of tensile strength and ductility were obtained by performing SPS on either milled or atomized powder at different temperatures. However, SPS consolidation failed to avoid heterogeneous microstructure composed of ultrafine-grained regions surrounded by micron grains despite of the rapid consolidation kinetics. A multi-scale characterization allowed to understand and model the evolution of this complex microstructure. An analytical evaluation of the contributing mechanisms can explain the appearance of the complex grain structure and its thermal stability during further heat treatments. Inhomogeneous distribution of plastic deformation in the powder is argued to be the major cause of heterogeneous recrystallization and further grain growth during hot consolidation. Even if increasing the solute content of yttrium, titanium and oxygen does not impede abnormal growth, it permits to control the fraction and the size of the retained ultrafine grains, which is a key-factor to tailor the mechanical properties. Since precipitation through grain boundary pinning plays a significant role on grain growth, a careful

  18. Ice sheet hydrology - a review

    Energy Technology Data Exchange (ETDEWEB)

    Jansson, Peter; Naeslund, Jens-Ove [Dept. of Physical Geography and Quaternary Geology, Stockholm Univ., Stockholm (Sweden); Rodhe, Lars [Geological Survey of Sweden, Uppsala (Sweden)

    2007-03-15

    This report summarizes the theoretical knowledge on water flow in and beneath glaciers and ice sheets and how these theories are applied in models to simulate the hydrology of ice sheets. The purpose is to present the state of knowledge and, perhaps more importantly, identify the gaps in our understanding of ice sheet hydrology. Many general concepts in hydrology and hydraulics are applicable to water flow in glaciers. However, the unique situation of having the liquid phase flowing in conduits of the solid phase of the same material, water, is not a commonly occurring phenomena. This situation means that the heat exchange between the phases and the resulting phase changes also have to be accounted for in the analysis. The fact that the solidus in the pressure-temperature dependent phase diagram of water has a negative slope provides further complications. Ice can thus melt or freeze from both temperature and pressure variations or variations in both. In order to provide details of the current understanding of water flow in conjunction with deforming ice and to provide understanding for the development of ideas and models, emphasis has been put on the mathematical treatments, which are reproduced in detail. Qualitative results corroborating theory or, perhaps more often, questioning the simplifications made in theory, are also given. The overarching problem with our knowledge of glacier hydrology is the gap between the local theories of processes and the general flow of water in glaciers and ice sheets. Water is often channelized in non-stationary conduits through the ice, features which due to their minute size relative to the size of glaciers and ice sheets are difficult to incorporate in spatially larger models. Since the dynamic response of ice sheets to global warming is becoming a key issue in, e.g. sea-level change studies, the problems of the coupling between the hydrology of an ice sheet and its dynamics is steadily gaining interest. New work is emerging

  19. Modelling the Antarctic Ice Sheet

    DEFF Research Database (Denmark)

    Pedersen, Jens Olaf Pepke; Holm, A.

    2015-01-01

    to sea level high stands during past interglacial periods. A number of AIS models have been developed and applied to try to understand the workings of the AIS and to form a robust basis for future projections of the AIS contribution to sea level change. The recent DCESS (Danish Center for Earth System......The Antarctic ice sheet is a major player in the Earth’s climate system and is by far the largest depository of fresh water on the planet. Ice stored in the Antarctic ice sheet (AIS) contains enough water to raise sea level by about 58 m, and ice loss from Antarctica contributed significantly...

  20. Ice sheet hydrology - a review

    International Nuclear Information System (INIS)

    Jansson, Peter; Naeslund, Jens-Ove; Rodhe, Lars

    2007-03-01

    This report summarizes the theoretical knowledge on water flow in and beneath glaciers and ice sheets and how these theories are applied in models to simulate the hydrology of ice sheets. The purpose is to present the state of knowledge and, perhaps more importantly, identify the gaps in our understanding of ice sheet hydrology. Many general concepts in hydrology and hydraulics are applicable to water flow in glaciers. However, the unique situation of having the liquid phase flowing in conduits of the solid phase of the same material, water, is not a commonly occurring phenomena. This situation means that the heat exchange between the phases and the resulting phase changes also have to be accounted for in the analysis. The fact that the solidus in the pressure-temperature dependent phase diagram of water has a negative slope provides further complications. Ice can thus melt or freeze from both temperature and pressure variations or variations in both. In order to provide details of the current understanding of water flow in conjunction with deforming ice and to provide understanding for the development of ideas and models, emphasis has been put on the mathematical treatments, which are reproduced in detail. Qualitative results corroborating theory or, perhaps more often, questioning the simplifications made in theory, are also given. The overarching problem with our knowledge of glacier hydrology is the gap between the local theories of processes and the general flow of water in glaciers and ice sheets. Water is often channelized in non-stationary conduits through the ice, features which due to their minute size relative to the size of glaciers and ice sheets are difficult to incorporate in spatially larger models. Since the dynamic response of ice sheets to global warming is becoming a key issue in, e.g. sea-level change studies, the problems of the coupling between the hydrology of an ice sheet and its dynamics is steadily gaining interest. New work is emerging

  1. Sheet Beam Klystron Instability Analysis

    International Nuclear Information System (INIS)

    Bane, K.

    2009-01-01

    Using the principle of energy balance we develop a 2D theory for calculating growth rates of instability in a two-cavity model of a sheet beam klystron. An important ingredient is a TE-like mode in the gap that also gives a longitudinal kick to the beam. When compared with a self-consistent particle-in-cell calculation, with sheet beam klystron-type parameters, agreement is quite good up to half the design current, 65 A; at full current, however, other, current-dependent effects come in and the results deviate significantly

  2. The social balance sheet 2004

    OpenAIRE

    Ph. Delhez; P. Heuse

    2005-01-01

    Each year, in the 4th quarter’s Economic Review, the National Bank examines the provisional results of the social balance sheets. As all the social balance sheets are not yet available for 2004, the study is based on a limited population of enterprises, compiled according to the principle of a constant sample. This population is made up of 38,530 enterprises employing around 1,331,000 workers in 2004. The main results of the analysis, in terms of employment, working hours, labour cost and tra...

  3. A complex interaction of imprinted and maternal-effect genes modifies sex determination in Odd Sex (Ods) mice.

    Science.gov (United States)

    Poirier, Christophe; Qin, Yangjun; Adams, Carolyn P; Anaya, Yanett; Singer, Jonathan B; Hill, Annie E; Lander, Eric S; Nadeau, Joseph H; Bishop, Colin E

    2004-11-01

    The transgenic insertional mouse mutation Odd Sex (Ods) represents a model for the long-range regulation of Sox9. The mutation causes complete female-to-male sex reversal by inducing a male-specific expression pattern of Sox9 in XX Ods/+ embryonic gonads. We previously described an A/J strain-specific suppressor of Ods termed Odsm1(A). Here we show that phenotypic sex depends on a complex interaction between the suppressor and the transgene. Suppression can be achieved only if the transgene is transmitted paternally. In addition, the suppressor itself exhibits a maternal effect, suggesting that it may act on chromatin in the early embryo.

  4. Oxidation behavior of HVOF sprayed Ni-5Al coatings deposited on Ni- and Fe-based superalloys under cyclic condition

    International Nuclear Information System (INIS)

    Mahesh, R.A.; Jayaganthan, R.; Prakash, S.

    2008-01-01

    Ni-5Al coating was obtained on three superalloy substrates viz. Superni 76, Superni 750 and Superfer 800 using high velocity oxy-fuel (HVOF) spray process. Oxidation studies were carried out on both bare and coated superalloy substrates in air at 900 deg. C for 100 cycles. The weight change was measured at the end of each cycle and observed that the weight gain was high in Superni 750 alloy when compared to Superni 76 and Superfer 800. A nearly parabolic oxidation behavior was observed for Ni-5Al coated Superni 750 and Superfer 800 alloys but a Ni-5Al coated Superni 76 substrate showed a slight deviation. The scale was analysed using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX) and electron probe microanalysis (EPMA). The coating increased the oxidation resistance for all the alloy substrates at 900 deg. C. Among the three-coated superalloys, Superfer 800 substrate has shown the best resistance to oxidation. The protective nature of the Ni-5Al coated superalloys was due to the formation of protective oxide scales such as NiO, Al 2 O 3 and Cr 2 O 3

  5. Modeling Long-term Creep Performance for Welded Nickel-base Superalloy Structures for Power Generation Systems

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Chen [GE Global Research, NIskayuna, NY (United States); Gupta, Vipul [GE Global Research, NIskayuna, NY (United States); Huang, Shenyan [GE Global Research, NIskayuna, NY (United States); Soare, Monica [GE Global Research, NIskayuna, NY (United States); Zhao, Pengyang [GE Global Research, NIskayuna, NY (United States); Wang, Yunzhi [GE Global Research, NIskayuna, NY (United States)

    2017-02-28

    The goal of this project is to model long-term creep performance for nickel-base superalloy weldments in high temperature power generation systems. The project uses physics-based modeling methodologies and algorithms for predicting alloy properties in heterogeneous material structures. The modeling methodology will be demonstrated on a gas turbine combustor liner weldment of Haynes 282 precipitate-strengthened nickel-base superalloy. The major developments are: (1) microstructure-property relationships under creep conditions and microstructure characterization (2) modeling inhomogeneous microstructure in superalloy weld (3) modeling mesoscale plastic deformation in superalloy weld and (4) a constitutive creep model that accounts for weld and base metal microstructure and their long term evolution. The developed modeling technology is aimed to provide a more efficient and accurate assessment of a material’s long-term performance compared with current testing and extrapolation methods. This modeling technology will also accelerate development and qualification of new materials in advanced power generation systems. This document is a final technical report for the project, covering efforts conducted from October 2014 to December 2016.

  6. Microstructural characterization of a modified 706-type Ni-Fe superalloy by small-angle neutron scattering and electron microscopy

    Czech Academy of Sciences Publication Activity Database

    Del Genovese, D.; Strunz, Pavel; Mukherji, D.; Gilles, R.; Rösler, J.

    36A, - (2005), s. 3439-3450 ISSN 1073-5623 Institutional research plan: CEZ:AV0Z10480505 Keywords : superalloys * small-angle neutron scattering Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.232, year: 2005

  7. Superalloys. Volume 2. 1977-February 1978 (citations from the NTIS data base). Report for 1977--Feb 78

    International Nuclear Information System (INIS)

    Smith, M.F.

    1978-03-01

    Federally-funded research on cobalt- and nickel-based superalloys is cited. Casting and powder metallurgy of these alloys are covered. Properties such as heat resistance, corrosion resistance, microstructure, fracture, and creep are described. The use of these materials in nuclear reactors, gas turbine parts, and high-temperature equipment is a major part of this compilation

  8. Transformed model fitting. A straightforward approach to evaluation of anisotropic SANS from nickel-base single-crystal superalloys

    International Nuclear Information System (INIS)

    Strunz, P.

    1999-01-01

    Schematic description of a special evaluation procedure for data treatment of anisotropic Small-Angle Neutron Scattering (SANS) is presented. The use of the discussed procedure is demonstrated on a data taken from investigation of precipitation in single-crystal nickel-base superalloys. (author)

  9. Influence of dwell times on the thermomechanical fatigue behavior of a directionally solidified Ni-base superalloy

    Czech Academy of Sciences Publication Activity Database

    Guth, S.; Petráš, Roman; Škorík, Viktor; Kruml, Tomáš; Man, Jiří; Lang, K. H.; Polák, Jaroslav

    2015-01-01

    Roč. 80, NOV (2015), s. 426-433 ISSN 0142-1123 R&D Projects: GA MŠk(CZ) EE2.3.30.0063 Institutional support: RVO:68081723 Keywords : Nickel base superalloy * Thermomechanical fatigue * Dwell time * Lifetime behavior * Damage mechanisms Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.162, year: 2015

  10. Effect of yttrium addition on the microstructure and mechanical properties of ODS RAF steels

    International Nuclear Information System (INIS)

    Auger, M.A.; Castro, V. de; Leguey, T.; Tarcísio-Costa, J.; Monge, M.A.; Muñoz, A.; Pareja, R.

    2014-01-01

    An oxide dispersion strengthened (ODS) alloy with nominal composition Fe–14Cr–2W–0.3Ti–0.24Y (wt.%) was produced by mechanical alloying using elemental powders, and subsequent hot isostatic pressing. The microstructure of the material and characteristics of the oxide particle dispersion were investigated by electron microscopy. The effect of heat treatments on the microhardness and tensile properties at room temperature was also studied. The results show that a fine dispersion of Y–O-rich nanoparticles is achieved, together with larger (Cr, Ti)-rich precipitates. The absence of Ti is apparent in the majority of these nanoparticles, in contrast with reported results for ODS Ti-modified steels processed with Y 2 O 3 addition

  11. Broadband polarized emission from P(NDI2OD-T2) polymer.

    Science.gov (United States)

    Ulrich, Steve; Sutch, Tabitha; Szulczewski, Greg; Schweizer, Matthias; Barbosa, Newton; Araujo, Paulo

    2018-05-18

    We investigate the P(NDI2OD-T2) photophysical properties via absorbance and fluorescence spectroscopy, in association with the experimental approach baptized Stokes Spectroscopy, which provides valuable material information through the acquisition and analysis of the fluorescence polarization degree. By changing solvents and using different samples such as solutions, thick, and thin films, it is possible to control the polarization degree spectrum associated to the fluorescence emitted by the polymer's isolated chains and aggregates. We show that the polarization degree could become a powerful tool to obtain information related to the samples morphology, which is connected to their microscopic structure. Moreover, the polarization degree spectra suggest that depolarization effects linked to energy and charge transfer mechanisms are likely taking place. Our findings indicate that P(NDI2OD-T2) polymers are excellent candidates for the advancement of organic technologies that rely on the emission and detection of polarized lights. © 2018 IOP Publishing Ltd.

  12. Logo-od: The applicability of Logotherapy as an organisation development intervention

    Directory of Open Access Journals (Sweden)

    Daniel H. Burger

    2008-11-01

    Full Text Available the study investigated the relationship between “resistance to or readiness for change” (ror-change and “meaning seeking”, and whether a logotherapy-based intervention – Logo-OD – would impact on resistance to change. A quasi-experimental design and various statistical procedures were applied to test formulated hypotheses. of a survey population of 1 637 individuals, 193 and 76 respondents formed part of the pre- and post-test samples respectively. Whereas a signifcant relationship was established between said constructs, no signifcant effect of Logo-OD was observed. These results supported the primary conclusions emanating from the literature: the role of logo-oD is one of a positive trigger event for organisational change.

  13. Effect of yttrium addition on the microstructure and mechanical properties of ODS RAF steels

    Energy Technology Data Exchange (ETDEWEB)

    Auger, M.A., E-mail: maria.auger@materials.ox.ac.uk [Departamento de Física, Universidad Carlos III de Madrid, Av Universidad 30, 28911 Leganés (Spain); Department of Materials, University of Oxford, Parks Road, OX1 3PH Oxford (United Kingdom); Castro, V. de; Leguey, T.; Tarcísio-Costa, J.; Monge, M.A.; Muñoz, A.; Pareja, R. [Departamento de Física, Universidad Carlos III de Madrid, Av Universidad 30, 28911 Leganés (Spain)

    2014-12-15

    An oxide dispersion strengthened (ODS) alloy with nominal composition Fe–14Cr–2W–0.3Ti–0.24Y (wt.%) was produced by mechanical alloying using elemental powders, and subsequent hot isostatic pressing. The microstructure of the material and characteristics of the oxide particle dispersion were investigated by electron microscopy. The effect of heat treatments on the microhardness and tensile properties at room temperature was also studied. The results show that a fine dispersion of Y–O-rich nanoparticles is achieved, together with larger (Cr, Ti)-rich precipitates. The absence of Ti is apparent in the majority of these nanoparticles, in contrast with reported results for ODS Ti-modified steels processed with Y{sub 2}O{sub 3} addition.

  14. Three loci on mouse chromosome 5 and 10 modulate sex determination in XX Ods/+ mice.

    Science.gov (United States)

    Poirier, Christophe; Moran, Jennifer L; Kovanci, Ertug; Petit, Deborah C; Beier, David R; Bishop, Colin E

    2007-07-01

    In mouse, XY embryos are committed to the male sex determination pathway after the transient expression of the Y-linked Sry gene in the Sertoli cell lineage between 10.5 and 12.5 dpc. In the C57BL/6J strain, male sex determination program can be modulated by some autosomal genes. The C57BL/6J alleles at these autosomal loci can antagonize male sex determination in combination with specific Sry alleles. In this report, the authors have identified an effect of these C57BL/6J specific alleles in combination with a mutated Sox9 allele, Sox9(Ods). Authors report the mapping of three of these genetic loci on mouse chromosome 5 and 10 in a backcross of the Ods mutation to the C57BL/6J background. Our study confirms the importance of the strain C57BL/6J for the investigation of the genetic mechanisms that control sex determination.

  15. Characterization of non-endcapped polymeric ODS column for the separation of triacylglycerol positional isomers.

    Science.gov (United States)

    Gotoh, Naohiro; Matsumoto, Yumiko; Yuji, Hiromi; Nagai, Toshiharu; Mizobe, Hoyo; Ichioka, Kenji; Kuroda, Ikuma; Noguchi, Noriko; Wada, Shun

    2010-01-01

    The characteristics of a non-endcapped polymeric ODS column for the resolution of triacylglycerol positional isomers (TAG-PI) were examined using a recycle HPLC-atmospheric pressure chemical ionization/mass spectrometry system. A pair of TAG-PI containing saturated fatty acids at least 12 carbons was separated. Except for TAG-PI containing elaidic acid, pairs of TAG-PI containing three unsaturated fatty acids were not separated, even by recycle runs. These results indicate that the resolution of TAG-PI on a non-endcapped polymeric ODS stationary phase is realized by the recognition of the linear structure of the fatty acid and the binding position of the saturated fatty acid in TAG-PI. Chain length was also an important factor for resolution. This method may be a useful and simple for measuring the abundance ratio of TAG-PI containing saturated fatty acids in natural oils.

  16. Consideration of the oxide particle-dislocation interaction in 9Cr-ODS steel

    Science.gov (United States)

    Ijiri, Yuta; Oono, N.; Ukai, S.; Yu, Hao; Ohtsuka, S.; Abe, Y.; Matsukawa, Y.

    2017-05-01

    The interaction between oxide particles and dislocations in a 9Cr-ODS ferritic steel is investigated by both static and in situ TEM observation under dynamic straining conditions and room temperature. The measured obstacle strength (?) of the oxide particles was no greater than 0.80 and the average was 0.63. The dislocation loops around some coarsened particles were also observed. The calculated obstacle strength by a stress formula of the Orowan interaction is nearly equaled to the average experimental value. Not only cross-slip system but also the Orowan interaction should be considered as the main interaction mechanism between oxide particles and dislocation in 9CrODS ferritic steel.

  17. Texture evolution in Oxide Dispersion Strengthened (ODS) steel tubes during pilgering process

    Science.gov (United States)

    Vakhitova, E.; Sornin, D.; Barcelo, F.; François, M.

    2017-10-01

    Oxide Dispersion Strengthened (ODS) steels are foreseen as fuel cladding material in the coming generation of Sodium Fast Reactors (SFR). Cladding tubes are manufactured by hot extrusion and subsequent cold forming steps. In this study, a 9 wt% Cr ODS steel exhibiting α-γ phase transformation at high temperature is cold formed under industrial conditions with a large section reduction in two pilgering steps. The influence of pilgering process parameters and intermediate heat treatment on the microstructure evolution is studied experimentally using Electron Backscattering Diffraction (EBSD) and X-ray Diffraction (XRD) methods. Pilgered samples show elongated grains and a high texture formation with a preferential orientation along the rolling direction. During the heat treatment, grain morphology is recovered from elongated grains to almost equiaxed ones, while the well-known α-fiber texture presents an unexpected increase in intensity. The remarkable temperature stability of this fiber is attributed to a crystallographic structure memory effect during phase transformations.

  18. STS-79 Ku-band antenna, ODS and Spacehab module at PCR

    Science.gov (United States)

    1996-01-01

    The orbiter Ku-band antenna looms large in this view of the Space Shuttle Atlantis' payload bay. Visible just past the antenna system -- stowed on the starboard side of the payload bay wall -- is the Orbiter Docking System (ODS), and connected to the ODS via a tunnel is the Spacehab Double Module in the aft area of the payload bay. This photograph was taken from the starboard wing platform on the fifth level of the Payload Changeout Room (PCR) at Launch Pad 39A. Work is under way in the PCR to close Atlantis' payload bay doors for flight. Atlantis currently is being targeted for liftoff on Mission STS-79, the fourth docking of the U.S. Shuttle to the Russian Space Station Mir, around September 12.

  19. Transmission electron microscopy of oxide dispersion strengthened (ODS) molybdenum: effects of irradiation on material microstructure

    International Nuclear Information System (INIS)

    Baranwal, R.; Burke, M.G.

    2003-01-01

    Oxide dispersion strengthened (ODS) molybdenum has been characterized using transmission electron microscopy (TEM) to determine the effects of irradiation on material microstructure. This work describes the results-to-date from TEM characterization of unirradiated and irradiated ODS molybdenum. The general microstructure of the unirradiated material consists of fine molybdenum grains (< 5 (micro)m average grain size) with numerous low angle boundaries and isolated dislocation networks. 'Ribbon'-like lanthanum oxides are aligned along the working direction of the product form and are frequently associated with grain boundaries, serving to inhibit grain boundary and dislocation movement. In addition to the 'ribbons', discrete lanthanum oxide particles have also been detected. After irradiation, the material is characterized by the presence of nonuniformly distributed large (∼ 20 to 100 nm in diameter), multi-faceted voids, while the molybdenum grain size and oxide morphology appear to be unaffected by irradiation

  20. Enhancing the Oxidation Performance of Wrought Ni-Base Superalloy by Minor Additions of Active Elements

    Science.gov (United States)

    Tawancy, H. M.

    2016-12-01

    We show that the oxidation performance of Cr2O3-forming superalloy based upon the Ni-Cr-W system is significantly improved by the presence of minor concentrations of La, Si and Mn, which outweigh the detrimental effect of high W concentration in the alloy. Although Cr2O3 is known to transform into volatile CrO3 at temperatures ≥950 °C, the respective protection is extended to temperatures reaching 1150 °C, which has also been correlated with the beneficial effects of La, Si and Mn. During high-temperature oxidation, an inner protective La- and Si-modified layer of α-Cr2O3 in contact with the superalloy substrate is developed and shielded by an outermost layer of MnCr2O4. The distribution of La and Si in the inner oxide layer has been characterized down to the scale of transmission electron microscopy, and the possible mechanisms underlying their beneficial effects are elucidated.

  1. Castability of Traditionally Wrought Ni-Based Superalloys for USC Steam Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Jablonski, P D; Cowen, C J; Hawk, J A; Evens, N; Maziasz, P

    2011-02-27

    The high temperature components within conventional coal fired power plants are manufactured from ferritic/martensitic steels. In order to reduce greenhouse gas emissions the efficiency of pulverized coal steam power plants must be increased. The proposed steam temperature in the Advanced Ultra Supercritical (A-USC) power plant is high enough (760°C) that ferritic/martensitic steels will not work due to temperature limitations of this class of materials; thus Ni-based superalloys are being considered. The full size castings are quite substantial: ~4in thick, several feet in diameter and weigh 5-10,000lb each half. Experimental castings were quite a bit smaller, but section size was retained and cooling rate controlled in order to produce relevant microstructures. A multi-step homogenization heat treatment was developed in order to better deploy the alloy constituents. The castability of two traditionally wrought Ni-based superalloys to which minor alloy adjustments have been made in order to improve foundry performance is further explored.

  2. Role of tantalum in the hot corrosion of a Ni-base single crystal superalloy

    International Nuclear Information System (INIS)

    Chang, J.X.; Wang, D.; Liu, T.; Zhang, G.; Lou, L.H.; Zhang, J.

    2015-01-01

    Highlights: • Ta is beneficial to hot corrosion resistance. • Ta promoted the formation of a new type sulphide TaS 2 . • Thermodynamic factors affect the constituent of sulphide layer. • Ta can substitute Cr for sulphur catcher in hot corrosion. • The result provides new perspective in hot corrosion resistant superalloys design. - Abstract: Hot corrosion behaviour of a Ni-base single crystal superalloy with low Cr, Ti and high Ta contents in molten sodium sulphate (Na 2 SO 4 ) at 900 °C in static air was investigated using the “deposit recoat” method. The corrosion scale was composed of an outer NiO layer, an inner Al 2 O 3 -dominant oxide network layer and a (CrS x(1.000

  3. Prediction of recrystallisation in single crystal nickel-based superalloys during investment casting

    Directory of Open Access Journals (Sweden)

    Panwisawas Chinnapat

    2014-01-01

    Full Text Available Production of gas turbines for jet propulsion and power generation requires the manufacture of turbine blades from single crystal nickel-based superalloys, most typically using investment casting. During the necessary subsequent solution heat treatment, the formation of recrystallised grains can occur. The introduction of grain boundaries into a single crystal component is potentially detrimental to performance, and therefore manufacturing processes and/or component geometries should be designed to prevent their occurrence. If the boundaries have very low strength, they can degrade the creep and fatigue properties. The root cause for recrystallisation is microscale plasticity caused by differential thermal contraction of metal, mould and core; when the plastic deformation is sufficiently large, recrystallisation takes place. In this work, numerical and thermo-mechanical modelling is carried out, with the aim of establishing computational methods by which recrystallisation during the heat treatment of single crystal nickel-based superalloys can be predicted and prevented prior to their occurrence. Elasto-plastic law is used to predict the plastic strain necessary for recrystallisation. The modelling result shows that recrystallisation is most likely to occur following 1.5–2.5% plastic strain applied at temperatures between 1000 ∘C and 1300 ∘C; this is validated with tensile tests at these elevated temperatures. This emphasises that high temperature deformation is more damaging than low temperature deformation.

  4. Experimental investigation on the spiral trepanning of K24 superalloy with femtosecond laser

    Science.gov (United States)

    Wang, Maolu; Yang, Lijun; Zhang, Shuai; Wang, Yang

    2018-05-01

    Film cooling holes are crucial for improving the performance of the aviation engine. In the paper, the processing of the film cooling holes on K24 superalloy by femtosecond laser is investigated. By comparing the three different drilling methods, the spiral trepanning method is chosen, and all the drilling experiments are carried out in this way. The experimental results show that the drilling of femtosecond laser pulses has distinct merits against that of the traditional long pulse laser, which can realize the "cold" processing with less recasting layer and less crack. The influence of each process parameter on roundness and taper, which are the important parameters to measure the quality of holes, is analyzed in detail, and the method to decrease it is proposed. To further reduce the recasting layer, the processing quality of the inner wall of the micro hole is investigated by scanning electron microscopy (SEM) equipped with energy disperse spectroscopy (EDS), the mechanism of the femtosecond laser interaction with K24 superalloy is further revealed. The investigation to the film hole machining by femtosecond laser has important practical significance.

  5. Fatigue Resistance of the Grain Size Transition Zone in a Dual Microstructure Superalloy Disk

    Science.gov (United States)

    Gabb, T. P.; Kantzos, P. T.; Telesman, J.; Gayda, J.; Sudbrack, C. K.; Palsa, B. S.

    2010-01-01

    Mechanical property requirements vary with location in nickel-based superalloy disks. To maximize the associated mechanical properties, heat treatment methods have been developed for producing tailored microstructures. In this study, a specialized heat treatment method was applied to produce varying grain microstructures from the bore to the rim portions of a powder metallurgy processed nickel-based superalloy disk. The bore of the contoured disk consisted of fine grains to maximize strength and fatigue resistance at lower temperatures. The rim microstructure of the disk consisted of coarse grains for maximum resistance to creep and dwell crack growth at high temperatures up to 704 C. However, the fatigue resistance of the grain size transition zone was unclear, and needed to be evaluated. This zone was located as a band in the disk web between the bore and rim. Specimens were extracted parallel and transverse to the transition zone, and multiple fatigue tests were performed at 427 and 704 C. Mean fatigue lives were lower at 427 C than for 704 C. Specimen failures often initiated at relatively large grains, which failed on crystallographic facets. Grain size distributions were characterized in the specimens, and related to the grains initiating failures as well as location within the transition zone. Fatigue life decreased with increasing maximum grain size. Correspondingly, mean fatigue resistance of the transition zone was slightly higher than that of the rim, but lower than that of the bore. The scatter in limited tests of replicates was comparable for all transition zone locations examined.

  6. High Temperature Degradation of Powder-processed Ni-based Superalloy

    Directory of Open Access Journals (Sweden)

    Natália Luptáková

    2015-05-01

    Full Text Available The aim of present work is to study the high temperature degradation of the powder-processed polycrystalline superalloy Ni-15Cr-18Co-4Al-3.5Ti-5Mo. This superalloy has been applied as material for grips of a creep machine. The material was exposed at 1100 °C for about 10 days at 10 MPa stress. During the creep test occurred unacceptable creep deformation of grips as well as severe surface oxidation with scales peeling off. Three types of the microstructure were observed in the studied alloy: (i unexposed state; (ii heat treated (annealing - 10 min/1200 °C and (iii after using as a part of the equipment of the creep machine during the creep test. It is shown that the microstructure degradation resulting from the revealed γ´ phase fcc Ni3(Al,Ti particles preferentially created at the grain boundaries of the samples after performing creep tests affects mechanical properties of the alloy and represents a significant contribution to all degradation processes affecting performance and service life of the creep machine grips. Based on investigation and obtained results, the given material is not recommended to be used for grips of creep machine at temperatures above 1000 °C.

  7. Solidification behaviors of a single-crystal superalloy under lateral constraints

    International Nuclear Information System (INIS)

    Zhuangqi Hu; Huaming Wang

    1993-01-01

    The effect of lateral constraints ahead of solidification interface on the solidification behaviors of a newly developed hot corrosion resistant single-crystal nickel-base superalloy was investigated under commercial single-crystal production conditions. The lateral constraints or section variations ahead of solidification front were found to have drastic influences both on the modes of solidification and the profiles of solute segregation. As lateral constraints were imposed ahead of the directionally solidifying interface, the solidification microstructure of the single-crystal superalloy changed suddenly, through a γ/γ' eutectic-free zone which is characterized by an extremely-fine and highly-developed dendrite network, from the original well-branched dendritic structure to a fine cellular-dendrite or regular cell structure, accompanying which the primary arm spacing, the severity of segregation and the amount of microporosity decreased remarkably. The newly formed cellular dendrite or cell structure transforms always gradually to the initial coarse dendrite structure as the lateral constraint is finally released whether gradually or sharply. Moreover, an abnormal porosity zone was readily observed in the initial section beneath and away from the eutectic-free zone. The solidification microstructural changes were attributed to the drastic dynamical changes in local solidification cooling conditions and in momentum transport during solidification due to the presence of lateral constraint

  8. Additive Manufacturing of Nickel Superalloys: Opportunities for Innovation and Challenges Related to Qualification

    Science.gov (United States)

    Babu, S. S.; Raghavan, N.; Raplee, J.; Foster, S. J.; Frederick, C.; Haines, M.; Dinwiddie, R.; Kirka, M. K.; Plotkowski, A.; Lee, Y.; Dehoff, R. R.

    2018-06-01

    Innovative designs for turbines can be achieved by advances in nickel-based superalloys and manufacturing methods, including the adoption of additive manufacturing. In this regard, selective electron beam melting (SEBM) and selective laser melting (SLM) of nickel-based superalloys do provide distinct advantages. Furthermore, the direct energy deposition (DED) processes can be used for repair and reclamation of nickel alloy components. The current paper explores opportunities for innovation and qualification challenges with respect to deployment of AM as a disruptive manufacturing technology. In the first part of the paper, fundamental correlations of processing parameters to defect tendency and microstructure evolution will be explored using DED process. In the second part of the paper, opportunities for innovation in terms of site-specific control of microstructure during processing will be discussed. In the third part of the paper, challenges in qualification of AM parts for service will be discussed and potential methods to alleviate these issues through in situ process monitoring, and big data analytics are proposed.

  9. Creep Crack Initiation and Growth Behavior for Ni-Base Superalloys

    Science.gov (United States)

    Nagumo, Yoshiko; Yokobori, A. Toshimitsu, Jr.; Sugiura, Ryuji; Ozeki, Go; Matsuzaki, Takashi

    The structural components which are used in high temperature gas turbines have various shapes which may cause the notch effect. Moreover, the site of stress concentration might have the heterogeneous microstructural distribution. Therefore, it is necessary to clarify the creep fracture mechanism for these materials in order to predict the life of creep fracture with high degree of accuracy. In this study, the creep crack growth tests were performed using in-situ observational testing machine with microscope to observe the creep damage formation and creep crack growth behavior. The materials used are polycrystalline Ni-base superalloy IN100 and directionally solidified Ni-base superalloy CM247LC which were developed for jet engine turbine blades and gas turbine blades in electric power plants, respectively. The microstructural observation of the test specimens was also conducted using FE-SEM/EBSD. Additionally, the analyses of two-dimensional elastic-plastic creep finite element using designed methods were conducted to understand the effect of microstructural distribution on creep damage formation. The experimental and analytical results showed that it is important to determine the creep crack initiation and early crack growth to predict the life of creep fracture and it is indicated that the highly accurate prediction of creep fracture life could be realized by measuring notch opening displacement proposed as the RNOD characteristic.

  10. High-temperature γ (FCC/γ′ (L12 Co-Al-W based superalloys

    Directory of Open Access Journals (Sweden)

    Knop Matthias

    2014-01-01

    Full Text Available Interim results from the development of a polycrystalline Co-Al-W based superalloy are presented. Cr has been added to provide oxidation resistance and Ni has then been added to widen and stabilise the γ′ phase field. The alloy presented has a solvus of 1010 °C and a density of 8.7 g cm−3. The room temperature flow stress is over 1000 MPa and this reduces dramatically above 800 °C. The flow stress anomaly is observed. A microstructure with both ∼ 50 nm γ′ produced on cooling and larger 100–200 nm γ′ can be obtained. Isothermal oxidation at 800 °C in air for 200 h gave a mass gain of 0.96 mg cm−2. After hot deformation in the 650–850 °C temperature range, both anti phase boundaries (APBs and stacking faults could be observed. An APB energy of 71 mJ m−2 was measured, which is comparable to that found in commercial nickel superalloys.

  11. Cyclic Oxidation and Hot Corrosion Behavior of Nickel-Iron-Based Superalloy

    Science.gov (United States)

    Chellaganesh, D.; Adam Khan, M.; Winowlin Jappes, J. T.; Sathiyanarayanan, S.

    2018-01-01

    The high temperature oxidation and hot corrosion behavior of nickel-iron-based superalloy are studied at 900 ° and 1000 °C. The significant role of alloying elements with respect to the exposed medium is studied in detail. The mass change per unit area was catastrophic for the samples exposed at 1000 °C and gradual increase in mass change was observed at 900 °C for both the environments. The exposed samples were further investigated with SEM, EDS and XRD analysis to study the metallurgical characteristics. The surface morphology has expressed the in situ nature of the alloy and its affinity toward the environment. The EDS and XRD analysis has evidently proved the presence of protective oxides formation on prolonged exposure at elevated temperature. The predominant oxide formed during the exposure at high temperature has a major contribution toward the protection of the samples. The nickel-iron-based superalloy is less prone to oxidation and hot corrosion when compared to the existing alloy in gas turbine engine simulating marine environment.

  12. Eddy Current Nondestructive Residual Stress Assessment in Shot-Peened Nickel-Base Superalloys

    International Nuclear Information System (INIS)

    Blodgett, M.P.; Yu, F.; Nagy, P.B.

    2005-01-01

    Shot peening and other mechanical surface enhancement methods improve the fatigue resistance and foreign-object damage tolerance of metallic components by introducing beneficial near-surface compressive residual stresses and hardening the surface. However, the fatigue life improvement gained via surface enhancement is not explicitly accounted for in current engine component life prediction models because of the lack of accurate and reliable nondestructive methods that could verify the presence of compressive near-surface residual stresses in shot-peened hardware. In light of its frequency-dependent penetration depth, the measurement of eddy current conductivity has been suggested as a possible means to allow the nondestructive evaluation of subsurface residual stresses in surface-treated components. This technique is based on the so-called piezoresistivity effect, i.e., the stress-dependence of electrical resistivity. We found that, in contrast with most other materials, surface-treated nickel-base superalloys exhibit an apparent increase in electrical conductivity at increasing inspection frequencies, i.e., at decreasing penetration depths. Experimental results are presented to illustrate that the excess frequency-dependent apparent eddy current conductivity of shot-peened nickel-base superalloys can be used to estimate the absolute level and penetration depth of the compressive residual stress layer both before and after partial thermal relaxation

  13. A phenomenological creep model for nickel-base single crystal superalloys at intermediate temperatures

    Science.gov (United States)

    Gao, Siwen; Wollgramm, Philip; Eggeler, Gunther; Ma, Anxin; Schreuer, Jürgen; Hartmaier, Alexander

    2018-07-01

    For the purpose of good reproduction and prediction of creep deformation of nickel-base single crystal superalloys at intermediate temperatures, a phenomenological creep model is developed, which accounts for the typical γ/γ‧ microstructure and the individual thermally activated elementary deformation processes in different phases. The internal stresses from γ/γ‧ lattice mismatch and deformation heterogeneity are introduced through an efficient method. The strain hardening, the Orowan stress, the softening effect due to dislocation climb along γ/γ‧ interfaces and the formation of dislocation ribbons, and the Kear–Wilsdorf-lock effect as key factors in the main flow rules are formulated properly. By taking the cube slip in \\{100\\} slip systems and \\{111\\} twinning mechanisms into account, the creep behavior for [110] and [111] loading directions are well captured. Without specific interaction and evolution of dislocations, the simulations of this model achieve a good agreement with experimental creep results and reproduce temperature, stress and crystallographic orientation dependences. It can also be used as the constitutive relation at material points in finite element calculations with complex boundary conditions in various components of superalloys to predict creep behavior and local stress distributions.

  14. Characterization and Modeling of Microstructure Development in Nickel-base Superalloy Welds

    Energy Technology Data Exchange (ETDEWEB)

    Babu, S.S.; David, S.A.; Miller, M.K.; Vitek, J.M.

    1999-11-01

    Welding is important for economical reuse and reclamation of used and failed nickel-base superalloy blades, respectively [1]. Solidification and solid state decomposition of {gamma} (Face Centered Cubic, FCC) phase into {gamma}{prime} (L1{sub 2}-ordered) phase control the properties of these welds. In previous publications, the microstructure development in electron beam welds of PWA-1480 alloy [2] and laser beam welds of CMSX-4 alloy [3] were presented. These results showed that the weld cracking in these alloys were associated with low melting point eutectic at the dendrite boundaries [1,2]. The eutectic-{gamma}{prime} precipitation was reduced at rapid weld cooling rates and the partitioning between {gamma}-{gamma}{prime} phase was found to be far from equilibrium conditions [3,4]. This observation was related to diffusional growth of {gamma}{prime} precipitate into {gamma} phase. Subsequent to the above work, the precipitation characteristics of {gamma}{prime} phase from {gamma} phase were evaluated during continuous cooling conditions [5]. The results show that the number density of {gamma} precipitates increased with an increase in cooling rate. However, the details of this decomposition and also the fine-scale elemental partitioning characteristics between {gamma}-{gamma}{prime} were not investigated. In this paper, the precipitation characteristics of {gamma}{prime} from {gamma} during continuous cooling conditions were investigated with transmission electron microscopy, and atom probe field ion microscopy. In addition, thermodynamic and kinetic models were used to describe microstructure development in Ni-base superalloy welds.

  15. Study on Plastic Deformation Characteristics of Shot Peening of Ni-Based Superalloy GH4079

    Science.gov (United States)

    Zhong, L. Q.; Liang, Y. L.; Hu, H.

    2017-09-01

    In this paper, the X-ray stress diffractometer, surface roughness tester, field emission scanning electron microscope(SEM), dynamic ultra-small microhardness tester were used to measure the surface residual stress and roughness, topography and surface hardness changes of GH4079 superalloy, which was processed by metallographic grinding, turning, metallographic grinding +shot peening and turning + shot peening. Analysized the effects of shot peening parameters on shot peening plastic deformation features; and the effects of the surface state before shot peening on shot peening plastic deformation characteristics. Results show that: the surface residual compressive stress, surface roughness and surface hardness of GH4079 superalloy were increased by shot peening, in addition, the increment of the surface residual compressive stress, surface roughness and surface hardness induced by shot peening increased with increasing shot peening intensity, shot peening time, shot peening pressure and shot hardness, but harden layer depth was not affected considerably. The more plastic deformation degree of before shot peening surface state, the less increment of the surface residual compressive stress, surface roughness and surface hardness induced by shot peening.

  16. The Formation and Evolution of Shear Bands in Plane Strain Compressed Nickel-Base Superalloy

    Directory of Open Access Journals (Sweden)

    Bin Tang

    2018-02-01

    Full Text Available The formation and evolution of shear bands in Inconel 718 nickel-base superalloy under plane strain compression was investigated in the present work. It is found that the propagation of shear bands under plane strain compression is more intense in comparison with conventional uniaxial compression. The morphology of shear bands was identified to generally fall into two categories: in “S” shape at severe conditions (low temperatures and high strain rates and “X” shape at mild conditions (high temperatures and low strain rates. However, uniform deformation at the mesoscale without shear bands was also obtained by compressing at 1050 °C/0.001 s−1. By using the finite element method (FEM, the formation mechanism of the shear bands in the present study was explored for the special deformation mode of plane strain compression. Furthermore, the effect of processing parameters, i.e., strain rate and temperature, on the morphology and evolution of shear bands was discussed following a phenomenological approach. The plane strain compression attempt in the present work yields important information for processing parameters optimization and failure prediction under plane strain loading conditions of the Inconel 718 superalloy.

  17. Synergistic effect of rhenium and ruthenium in nickel-based single-crystal superalloys

    Energy Technology Data Exchange (ETDEWEB)

    Yu, X.X. [Department of Physics, Tsinghua University, Beijing 100084 (China); Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Wang, C.Y., E-mail: cywang@mail.tsinghua.edu.cn [Department of Physics, Tsinghua University, Beijing 100084 (China); Central Iron and Steel Research Institute, Beijing 100081 (China); Zhang, X.N. [Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100124 (China); Yan, P. [Central Iron and Steel Research Institute, Beijing 100081 (China); Zhang, Z., E-mail: zezhang@zju.edu.cn [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China)

    2014-01-05

    Highlights: • Re and Ru synergistic effects in nickel-based superalloys are investigated. • The Al site occupation of Re atom in the γ′ phase is observed directly. • The addition of Ru results in the repartitioning of Re to γ phase. -- Abstract: The microstructures of ternary Ni–Al–Re and quaternary Ni–Al–Re–Ru single-crystal alloys were investigated at atomic and electronic levels to clarify the synergistic effect of Re and Ru in nickel-based single-crystal superalloys. In the Ni–Al–Re alloy, it was directly observed that Re atom occupied the Al site of γ′ phase. In the Ni–Al–Re–Ru alloy, the mechanisms of Re repartition between γ and γ′ phases were proposed. In the dendritic cores, high concentrations of Re exceeded the solubility limit of γ′ phase and partitioned to γ phase, which led to the homogenization. In the interdendritic regions, Ru resulted in the repartitioning of Re to γ phase which was proved by transmission electron microscopy and first-principles calculations.

  18. Control of microstructure and mechanical properties of laser solid formed Inconel 718 superalloy by electromagnetic stirring

    Science.gov (United States)

    Liu, Fencheng; Cheng, Hongmao; Yu, Xiaobin; Yang, Guang; Huang, Chunping; Lin, Xin; Chen, Jing

    2018-02-01

    The coarse columnar grains and special interface in laser solid formed (LSFed) Inconel 718 superalloy workpieces seriously affect their mechanical properties. To improve the microstructure and mechanical properties of LSFed Inconel 718 superalloy, electromagnetic stirring (EMS) was introduced to alter the solidification process of the molten pool during LSF. The results show that EMS could not completely eliminate the epitaxially growing columnar grains, however, the strong convection of liquid metals can effectively influence the solid-liquid interface growing mode. The segregation of alloying elements on the front of solid-liquid interface is inhibited and the degree of constitutional supercooling decreases correspondingly. Comparing the microstructures of samples formed under different process parameters, the size and amount of the γ+Laves eutectic phases formed in interdendritic area decrease along with the increasing magnetic field intensity, resulting in more uniformly distributed alloying elements. The residual stress distribution is proved to be more uniform, which is beneficial to the grain refinement after recrystallilzaiton. Mechanical properties testing results show an improvement of 100 MPa in tensile strength and 22% in elongation was obtained after EMS was used. The high cycle fatigue properties at room temperature was also improved from 4.09 × 104 cycles to 8.21 × 104 cycles for the as-deposited samples, and from 5.45 × 104 cycles to 12.73 × 104 cycles for the heat treated samples respectively.

  19. Very High Cycle Fatigue of Ni-Based Single-Crystal Superalloys at High Temperature

    Science.gov (United States)

    Cervellon, A.; Cormier, J.; Mauget, F.; Hervier, Z.; Nadot, Y.

    2018-05-01

    Very high cycle fatigue (VHCF) properties at high temperature of Ni-based single-crystal (SX) superalloys and of a directionally solidified (DS) superalloy have been investigated at 20 kHz and a temperature of 1000 °C. Under fully reversed conditions (R = - 1), no noticeable difference in VHCF lifetimes between all investigated alloys has been observed. Internal casting pores size is the main VHCF lifetime-controlling factor whatever the chemical composition of the alloys. Other types of microstructural defects (eutectics, carbides), if present, may act as stress concentration sites when the number of cycles exceed 109 cycles or when porosity is absent by applying a prior hot isostatic pressing treatment. For longer tests (> 30 hours), oxidation also controls the main crack initiation sites leading to a mode I crack initiation from oxidized layer. Under such conditions, alloy's resistance to oxidation has a prominent role in controlling the VHCF. When creep damage is present at high ratios (R ≥ 0.8), creep resistance of SX/DS alloys governs VHCF lifetime. Under such high mean stress conditions, SX alloys developed to retard the initiation and creep propagation of mode I micro-cracks from pores have better VHCF lifetimes.

  20. Spray forming and mechanical properties of a new type powder metallurgy superalloy

    International Nuclear Information System (INIS)

    Jia Chong-Lin; Ge Chang-Chun; Xia Min; Gu Tian-Fu

    2015-01-01

    The deposited billet of a new type powder metallurgy (PM) superalloy FGH4095M for use in turbine disk manufacturing has been fabricated using spray forming technology. The metallurgical quality of the deposited billet was analyzed in terms of density, texture, and grain size. Comparative research was done on the microstructure and mechanical properties between the flat disk preform prepared with hot isostatic pressing (HIP) and the same alloy forgings prepared with HIP followed by isothermal forging (IF). The results show that the density of the spray-formed and nitrogen-atomized deposit billet is above 99% of the theoretical density, indicating a compact structure. The grains are uniform and fine. The billet has weak texture with a random distribution in the spray deposition direction and perpendicular to the direction of deposition. A part of atomizing nitrogen exists in the preform in the form of carbonitride. Nitrogen-induced microporosity causes the density reduction of the preform. Compared with the process of HIP+IF, the superalloy FGH4095M after HIP has better mechanical properties at both room temperature and high temperature. The sizes of the γ′ phase are finer in microstructure of the preform after HIP in comparison with the forgings after HIP+IF. This work shows that SF+HIP is a viable processing route for FGH4095M as a turbine-disk material. (paper)