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Sample records for fusion structural alloys

  1. Activation analyses for different fusion structural alloys

    International Nuclear Information System (INIS)

    Attaya, H.; Smith, D.

    1991-01-01

    The leading candidate structural materials, viz., the vanadium alloys, the nickel or the manganese stabilized austenitic steels, and the ferritic steels, are analysed in terms of their induced activation in the TPSS fusion power reactor. The TPSS reactor has 1950 MW fusion power and inboard and outboard average neutron wall loading of 3.75 and 5.35 MW/m 2 respectively. The results shows that, after one year of continuous operation, the vanadium alloys have the least radioactivity at reactor shutdown. The maximum difference between the induced radioactivity in the vanadium alloys and in the other iron-based alloys occurs at about 10 years after reactor shutdown. At this time, the total reactor radioactivity, using the vanadium alloys, is about two orders of magnitude less than the total reactor radioactivity utilizing any other alloy. The difference is even larger in the first wall, the FW-vanadium activation is 3 orders of magnitude less than other alloys' FW activation. 2 refs., 7 figs

  2. Vanadium alloys for structural applications in fusion systems: A review of vanadium alloy mechanical and physical properties

    Energy Technology Data Exchange (ETDEWEB)

    Loomis, B.A.; Smith, D.L.

    1991-12-16

    The current knowledge is reviewed on (1) the effects of neutron irradiation on tensile strength and ductility, ductile-brittle transition temperature, creep, fatigue, and swelling of vanadium-base alloys, (2) the compatibility of vanadium-base alloys with liquid lithium, water, and helium environments, and (3) the effects of hydrogen and helium on the physical and mechanical properties of vanadium alloys that are potential candidates for structural materials applications in fusion systems. Also, physical and mechanical properties issues are identified that have not been adequately investigated in order to qualify a vanadium-base alloy for the structural material in experimental fusion devices and/or in fusion reactors.

  3. Vanadium alloys for structural applications in fusion systems: A review of vanadium alloy mechanical and physical properties

    International Nuclear Information System (INIS)

    Loomis, B.A.; Smith, D.L.

    1991-01-01

    The current knowledge is reviewed on (1) the effects of neutron irradiation on tensile strength and ductility, ductile-brittle transition temperature, creep, fatigue, and swelling of vanadium-base alloys, (2) the compatibility of vanadium-base alloys with liquid lithium, water, and helium environments, and (3) the effects of hydrogen and helium on the physical and mechanical properties of vanadium alloys that are potential candidates for structural materials applications in fusion systems. Also, physical and mechanical properties issues are identified that have not been adequately investigated in order to qualify a vanadium-base alloy for the structural material in experimental fusion devices and/or in fusion reactors

  4. Fusion materials: Technical evaluation of the technology of vandium alloys for use as blanket structural materials in fusion power systems

    International Nuclear Information System (INIS)

    1993-01-01

    The Committee's evaluation of vanadium alloys as a structural material for fusion reactors was constrained by limited data and time. The design of the International Thermonuclear Experimental Reactor is still in the concept stage, so meaningful design requirements were not available. The data on the effect of environment and irradiation on vanadium alloys were sparse, and interpolation of these data were made to select the V-5Cr-5Ti alloy. With an aggressive, fully funded program it is possible to qualify a vanadium alloy as the principal structural material for the ITER blanket in the available 5 to 8-year window. However, the data base for V-5Cr-5Ti is United and will require an extensive development and test program. Because of the chemical reactivity of vanadium the alloy will be less tolerant of system failures, accidents, and off-normal events than most other candidate blanket structural materials and will require more careful handling during fabrication of hardware. Because of the cost of the material more stringent requirements on processes, and minimal historical worlding experience, it will cost an order of magnitude to qualify a vanadium alloy for ITER blanket structures than other candidate materials. The use of vanadium is difficult and uncertain; therefore, other options should be explored more thoroughly before a final selection of vanadium is confirmed. The Committee views the risk as being too high to rely solely on vanadium alloys. In viewing the state and nature of the design of the ITER blanket as presented to the Committee, h is obvious that there is a need to move toward integrating fabrication, welding, and materials engineers into the ITER design team. If the vanadium allay option is to be pursued, a large program needs to be started immediately. The commitment of funding and other resources needs to be firm and consistent with a realistic program plan

  5. Activation of structural alloys in fusion reactor magnets

    International Nuclear Information System (INIS)

    Mann, F.M.; Doran, D.G.

    1986-01-01

    Using the REAC2 code system, both short-term and long-term activation were calculated for possible structural and magnet materials at the shield-magnet interface. The flux was taken from the STARFIRE conceptual design and a 30-year lifetime was assumed. Short-term activation does not seem to be a problem. Only materials with large amounts of niobium appear to be a potential problem for long-term activation. 2 tabs

  6. XHM-1 alloy as a promising structural material for water-cooled fusion reactor components

    International Nuclear Information System (INIS)

    Solonin, M.I.; Alekseev, A.B.; Kazennov, Yu.I.; Khramtsov, V.F.; Kondrat'ev, V.P.; Krasina, T.A.; Rechitsky, V.N.; Stepankov, V.N.; Votinov, S.N.

    1996-01-01

    Experience gained in utilizing austenitic stainless steel components in water-cooled power reactors indicates that the main cause of their failure is the steel's propensity for corrosion cracking. In search of a material immune to this type of corrosion, different types of austenitic steels and chromium-nickel alloys were investigated and tested at VNIINM. This paper presents the results of studying physical and mechanical properties, irradiation and corrosion resistance in a water coolant at <350 C of the alloy XHM-1 as compared with austenitic stainless steels 00Cr16Ni15Mo3Nb, 00Cr20Ni25Nb and alloy 00Cr20Ni40Mo5Nb. Analysis of the results shows that, as distinct from the stainless steels studied, the XHM-1 alloy is completely immune to corrosion cracking (CC). Not a single induced damage was encountered within 50 to 350 C in water containing different amounts of chlorides and oxygen under tensile stresses up to the yield strength of the material. One more distinctive feature of the alloy compared to steels is that no change in the strength or total elongation is encountered in the alloy specimens irradiated to 32 dpa at 350 C. The XHM-1 alloy has adequate fabricability and high weldability characteristics. As far as its properties are concerned, the XHM-1 alloy is very promising as a material for water-cooled fusion reactor components. (orig.)

  7. Radiation damage simulation studies of selected austenitic and ferritic/martensitic alloys for fusion reactor structural applications

    International Nuclear Information System (INIS)

    Mazey, D.J.; Walters, G.P.; Buckley, S.N.; Bullough, R.; Hanks, W.; Bolster, D.E.J.; Sowden, B.C.; Lurcook, D.; Murphy, S.M.

    1985-03-01

    Results are given of an investigation of the radiation damage stability of selected austenitic and ferritic alloys following ion bombardment in the Harwell VEC to simulate fusion-reactor exposures up to 110 dpa at temperatures from 425 deg to 625 deg C. Gas production rates appropriate to CTR conditions were simulated using a mixed beam of (4 MeV He + 2 MeV H 2 ) in the ratio 1:4 He:H. A beam of 46 MeV Ni or 20 MeV Cr ions was used in sequence with the mixed gas beam to provide a gas/damage ratio of 13 appm He/dpa at a damage rate of approx. 1 dpa/hr. The materials were investigated using TEM and comprised three austenitic alloys: European reference 316L, 316-Ti, 316-Nb; four high-nickel alloys: Fe/25 Ni/8Cr, Inconel 625, Inconel 706 and Nimonic PE16, and four ferritic/martensitic alloys: FV 448, FV 607, CRM 12 and FI. Some data were obtained for a non-magnetic structural alloy Nonmagne-30. The swelling behaviour is reported. The overall results of the study indicate that on a comparative basis the ferritic alloys are the most swelling-resistant, whilst the high-nickel alloys have an acceptable low swelling response up to 110 dpa. The 316 alloys tested have shown an unfavourable swelling response. (author)

  8. Vanadium alloys for fusion reactor applications

    International Nuclear Information System (INIS)

    Mattas, R.F.; Loomis, B.A.; Smith, D.L.

    1992-01-01

    This paper reports that fusion reactors will produce a severe operating environment for structural materials. The material should have good mechanical strength and ductility to high temperature, be corrosion resistant to the local environment, have attractive thermophysical properties to accommodate high heat loads, and be resistant to neutron damage. Vanadium alloys are being developed for such applications, and they exhibit desirable properties in many areas Recent progress in vanadium alloy development indicates good strength and ductility to 700 degrees C, minimal degradation by neutron irradiation, and reduced radioactivity compared with other candidate alloy systems

  9. Vanadium-base alloys for fusion reactor applications

    International Nuclear Information System (INIS)

    Smith, D.L.; Loomis, B.A.; Diercks, D.R.

    1984-10-01

    Vanadium-base alloys offer potentially significant advantages over other candidate alloys as a structural material for fusion reactor first wall/blanket applications. Although the data base is more limited than that for the other leading candidate structural materials, viz., austenitic and ferritic steels, vanadium-base alloys exhibit several properties that make them particularly attractive for the fusion reactor environment. This paper presents a review of the structural material requirements, a summary of the materials data base for selected vanadium-base alloys, and a comparison of projected performance characteristics compared to other candidate alloys. Also, critical research and development (R and D) needs are defined

  10. Vanadium-base alloys for fusion reactor applications

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D.L.; Loomis, B.A.; Diercks, D.R.

    1984-10-01

    Vanadium-base alloys offer potentially significant advantages over other candidate alloys as a structural material for fusion reactor first wall/blanket applications. Although the data base is more limited than that for the other leading candidate structural materials, viz., austenitic and ferritic steels, vanadium-base alloys exhibit several properties that make them particularly attractive for the fusion reactor environment. This paper presents a review of the structural material requirements, a summary of the materials data base for selected vanadium-base alloys, and a comparison of projected performance characteristics compared to other candidate alloys. Also, critical research and development (R and D) needs are defined.

  11. 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.

  12. Fusion boundary microstructure evolution in aluminum alloys

    Science.gov (United States)

    Kostrivas, Anastasios Dimitrios

    2000-10-01

    A melting technique was developed to simulate the fusion boundary of aluminum alloys using the GleebleRTM thermal simulator. Using a steel sleeve to contain the aluminum, samples were heated to incremental temperatures above the solidus temperature of a number of alloys. In alloy 2195, a 4wt%Cu-1wt%Li alloy, an equiaxed non-dendritic zone (EQZ) could be formed by heating in the temperature range from approximately 630 to 640°C. At temperatures above 640°C, solidification occurred by the normal epitaxial nucleation and growth mechanism. Fusion boundary behavior was also studied in alloys 5454-H34, 6061-T6, and 2219-T8. Additionally, experimental alloy compositions were produced by making bead on plate welds using an alloy 5454-H32 base metal and 5025 or 5087 filler metals. These filler metals contain zirconium and scandium additions, respectively, and were expected to influence nucleation and growth behavior. Both as-welded and welded/heat treated (540°C and 300°C) substrates were tested by melting simulation, resulting in dendritic and EQZ structures depending on composition and substrate condition. Orientation imaging microscopy (OIM(TM)) was employed to study the crystallographic character of the microstructures produced and to verify the mechanism responsible for EQZ formation. OIM(TM) proved that grains within the EQZ have random orientation. In all other cases, where the simulated microstructures were dendritic in nature, it was shown that epitaxy was the dominant mode of nucleation. The lack of any preferred crystallographic orientation relationship in the EQZ supports a theory proposed by Lippold et al that the EQZ is the result of heterogeneous nucleation within the weld unmixed zone. EDS analysis of the 2195 on STEM revealed particles with ternary composition consisted of Zr, Cu and Al and a tetragonal type crystallographic lattice. Microdiffraction line scans on EQZ grains in the alloy 2195 showed very good agreement between the measured Cu

  13. Structural materials for fusion reactors

    International Nuclear Information System (INIS)

    Victoria, M.; Baluc, N.; Spaetig, P.

    2001-01-01

    In order to preserve the condition of an environmentally safe machine, present selection of materials for structural components of a fusion reactor is made not only on the basis of adequate mechanical properties, behavior under irradiation and compatibility with other materials and cooling media, but also on their radiological properties, i.e. activity, decay heat, radiotoxicity. These conditions strongly limit the number of materials available to a few families of alloys, generically known as low activation materials. We discuss the criteria for deciding on such materials, the alloys resulting from the application of the concept and the main issues and problems of their use in a fusion environment. (author)

  14. Development of fabrication technology for low activation vanadium alloys as fusion blanket structural materials

    International Nuclear Information System (INIS)

    Nagasaka, T.; Muroga, T.; Fukumoto, K.; Watanabe, H.; Grossbeck, M.L.; Chen, J.M.

    2005-01-01

    High purity vanadium alloy products, such as plates, wires and tubes, were fabricated from reference high-purity V-4Cr-4Ti ingots designated as NIFS-HEAT, by using technologies applicable to industrial scale fabrication. Impurity behavior during breakdown, and its effect on mechanical properties were investigated. It was revealed that mechanical properties of the products were significantly improved by the control of Ti-C, N, O precipitation induced during the processes. (author)

  15. Volatility from copper and tungsten alloys for fusion reactor applications

    International Nuclear Information System (INIS)

    Smolik, G.R.; Neilson, R.M. Jr.; Piet, S.J.

    1989-01-01

    Accident scenarios for fusion power plants present the potential for release and transport of activated constituents volatilized from first wall and structural materials. The extent of possible mobilization and transport of these activated species, many of which are ''oxidation driven'', is being addressed by the Fusion Safety Program at the Idaho National Engineering Laboratory (INEL). This report presents experimental measurements of volatilization from a copper alloy in air and steam and from a tungsten alloy in air. The major elements released included zinc from the copper alloy and rhenium and tungsten from the tungsten alloy. Volatilization rates of several constituents of these alloys over temperatures ranging from 400 to 1200 degree C are presented. These values represent release rates recommended for use in accident assessment calculations. 8 refs., 3 figs., 5 tabs

  16. Development of Al-Mg-Li alloys for fusion reactor

    International Nuclear Information System (INIS)

    Shoji, Yoshifusa; Yoshida, Hideo; Uno, Teruo; Baba, Yoshio; Kamada, Koji.

    1985-01-01

    Aluminum-magnesium-lithium alloys featuring low residual induced radioactivity and high electrical resistivity have been developed for fusion reactor structural materials. The addition of lithium in aluminum and Al-Mg alloys markedly increases electrical resistivity and tensile strength of them. However the elongation of Al-Mg-Li alloys containing more than 2 mass% lithium are less than 10 %. The Al-4--5 mass%Mg-1 mass%Li alloys are optimum for fusion reactor materials, and exhibit high resistivity (86 nΩm: 20 %IACS), medium strength (300 MPa) and good formability (22 % elongation). The variation of electrical resistivity of Al-Li and Al-Mg-Li alloys in solid solution can be approximated by the Matthiessen's rule. (author)

  17. Elemental volatility of HT-9 fusion reactor alloy

    International Nuclear Information System (INIS)

    Henslee, S.P.; Neilson, R.M. Jr.

    1985-01-01

    The volatility of elemental constituents from HT-9, a ferritic steel, proposed for fusion reactor structures, was investigated. Tests were conducted in flowing air at temperatures from 800 to 1200 0 C for durations of 1 to 20 h. Elemental volatility was calculated in terms of the weight fraction of the element volatilized from the initial alloy; molybdenum, manganese, and nickel were the primary constituents volatilized. Comparisons with elemental volatilities observed for another candidate fusion reactor materials. Primary Candidate Alloy (PCA), an austenitic stainless steel, indicate significant differences between the volatilities of these steels that may impact fusion reactor safety analysis and alloy selection. Scanning electron microscopy and energy dispersive spectrometry were used to investigate the oxide layers formed on HT-9 and to measure elemental contents within these layers

  18. Structural materials for fusion reactor blanket systems

    International Nuclear Information System (INIS)

    Bloom, E.E.; Smith, D.L.

    1984-01-01

    Consideration of the required functions of the blanket and the general chemical, mechanical, and physical properties of candidate tritium breeding materials, coolants, structural materials, etc., leads to acceptable or compatible combinations of materials. The presently favored candidate structural materials are the austenitic stainless steels, martensitic steels, and vanadium alloys. The characteristics of these alloy systems which limit their application and potential performance as well as approaches to alloy development aimed at improving performance (temperature capability and lifetime) will be described. Progress towards understanding and improving the performance of structural materials has been substantial. It is possible to develop materials with acceptable properties for fusion applications

  19. Manufacture of semifinished items of alloys V-4Ti-4Cr and V-10Ti-5Cr for use as a structural material in fusion applications

    International Nuclear Information System (INIS)

    Potapenko, M.M.; Drobishev, V.A.; Filkin, V.Y.; Gubkin, I.N.; Myasnikov, V.V.; Nikulin, A.D.; Shingarev, E.N.; Vedernikov, G.P.; Votinov, S.N.; Zurabov, V.S.; Zolotarev, A.B.

    1996-01-01

    Vanadium-titanium-chromium alloys are considered as structural materials with the most appropriate properties for fusion applications. However, the final ratio V-Ti-Cr in an alloy is not yet determined. On the one hand, it is offered to optimize structure on the basis of an alloy V-4Ti-4Cr. On the other hand, it is proposed that the optimum of total Ti and Cr content should be near 15%, and the Ti to Cr ratio should be 2:1. Melting, casting and processing by pressure of ingots of vanadium alloys V-4Ti-4Cr and V-10Ti-5Cr weighing as much as 50 kg are considered in the report. The ingots in diameters up to 130 mm were obtained by melting in vacuum-arc furnaces. Results on chemical uniformity and structure of the ingots are presented. A basic scheme of semifinished items manufacture is submitted. Rod and tube hot extrusion conditions are presented. A new technology for protection of ingot and billet surface from gases during hot processing is used to discard application of protective stainless steel and to lower temperature of processing. Sheet and tube products were made from extruded billets by cold rolling with intermediate heat treatment. The list of obtained products, including sheets 0.5-5 mm thick, rods 10-18 mm in diameter and tubes from 50 mm up to 6.0 mm in diameter is presented. The availability of large-scale ingots processing with weight above 300 kg is discussed. (orig.)

  20. Development of Zr-containing advanced reduced-activation alloy (ARAA) as structural material for fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Y.B., E-mail: borobang@gmail.com [Nuclear Materials Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kang, S.H. [Nuclear Materials Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, D.W. [Nuclear Fusion Engineering Development Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Cho, S. [National Fusion Research Institute, Daejeon (Korea, Republic of); Jeong, Y.H. [Nuclear Materials Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Żywczak, A. [AGH University of Science and Technology, Academic Centre of Materials and Nanotechnology, Kraków (Poland); Rhee, C.K. [Nuclear Materials Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-11-01

    Highlights: • Creep and impact resistances of reduced activation ferritic–martensitic steel are enhanced by the addition of Zr. • A 5 ton scale heat of Zr containing RAFM steel, ARAA, has been produced for material property evaluation. • The physical, thermal, magnetic and mechanical properties of ARAA are quite similar to those of Eurofer 97. - Abstract: Korea has developed an advanced reduced-activation alloy (ARAA) as a structural material for helium-cooled ceramic reflector test blanket module (HCCR-TBM) applications. The present paper describes the history of alloy development and the properties of ARAA, which has been produced at a 5 t scale using vacuum induction melting and electro-slag re-melting methods. ARAA is a 9Cr–1.2W based ferritic–martensitic steel with 0.01 wt.% Zr. The mechanical properties, thermal properties and physical and magnetic properties of ARAA show similar temperature dependencies to those observed for Eurofer 97. However, ARAA exhibits a much longer creep–rupture time than conventional RAFM steel, which suggests a positive effect on Zr addition. The enhanced creep strength of ARAA by the addition of Zr is attributed to the reduced temperature-dependence of the yield strength.

  1. Production of titanium alloy powders by vacuum fusion-centrifugation

    International Nuclear Information System (INIS)

    Decours, Jacques; Devillard, Jacques; Sainfort, G.

    1975-01-01

    This work presents a method of preparing powdered TA6V and TA6Z5D alloys by fusion-centrifugation under electron bombardment. An industrial capacity apparatus for the production of metallic powders is described and the characteristics of the powders obtained are presented. Solid parts were shaped by sintering and drawing at temperatures between 850 and 1100 deg C. The structure and mechanical properties of the cold densified products before and after heat treatment are compared [fr

  2. Development and testing ov danadium alloys for fusion applications

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H.M.; Loomis, B.A.; Smith, D.L.

    1996-10-01

    V base alloys have advantages for fusion reactor first-wall and blanket structure. To screen candidate alloys and optimize a V-base alloy, physical and mechanical properties of V-Ti, V-Cr-Ti, and V-Ti- Si alloys were studied before and after irradiation in Li environment in fast fission reactors. V-4Cr-4Ti containing 500-1000 wppM Si and <1000 wppM O+N+C was investigated as the most promising alloy, and more testing is being done. Major results of the work are presented in this paper. The reference V-4Cr-4Ti had the most attractive combination of the mechanical and physical properties that are prerequisite for first-wall and blanket structures: good thermal creep, good tensile strength/ductility, high impact energy, excellent resistance to swelling, and very low ductile-brittle transition temperature before and after irradiation. The alloy was highly resistant to irradiation-induced embrittlement in Li at 420-600 C, and the effects of dynamically charged He on swelling and mechanical properties were insignificant. However, several important issues remain unresolved: welding, low-temperature irradiation, He effect at high dose and high He concentration, irradiation creep, and irradiation performance in air or He. Initial results of investigation of some of these issues are also given.

  3. Development of ductile long-range ordered alloys for fusion reactor systems

    International Nuclear Information System (INIS)

    Liu, C.T.

    1979-01-01

    A series of Fe-base ordered alloys with compositions (Fe,Ni,Co) 3 V are developed for fusion reactor applications. The alloys from cubic ordered structure similar to AuCu 3 below their critical ordering temperature. The alloys in the ordered state are ductile with elongation in excess of 35% at room temperture. Tensile tests of the ordered alloys at elevated temperatures indicate an unusually attractive mechanical behavior. Their strength, instead of decreasing as with conventional alloys, increases with temperature because of ordering effects. As a result, the ordered alloys are much stronger than 316 stainless steel, particularly at elevated temperatures

  4. A vanadium alloy for the application in a liquid metal blanket of a fusion reactor

    Science.gov (United States)

    Borgstedt, H. U.; Grundmann, M.; Konys, J.; Perić, Z.

    1988-07-01

    The vanadium alloy V3Ti1Si has been corrosion tested in liquid lithium and the eutectic alloy Pb-17Li at 550°C. This alloy has a comparable corrosion resistance to the alloy V15Cr5Ti in lithium. In this molten metal it is superior to stainless steel AISI 316. In the Pb-17Li melt it is even superior to martensitic steels. The alloy has only a weak tendency to be dissolved. It is sensitive to an exchange of non-metallic elements, which causes the formation of a hardened surface layer. These chemical effects are influenced by the mass and surface ratios of the vanadium alloy to the molten metals and other structural materials. These ratios are unfavorable in the two test loops. The effects might be less pronounced in a vanadium alloy/liquid metal fusion reactor blanket.

  5. Structural materials challenges for fusion power systems

    International Nuclear Information System (INIS)

    Kurtz, Richard J.

    2009-01-01

    Full text: Structural materials in a fusion power system must function in an extraordinarily demanding environment that includes various combinations of high temperatures, reactive chemicals, time-dependent thermal and mechanical stresses, and intense damaging radiation. The fusion neutron environment produces displacement damage equivalent to displacing every atom in the material about 150 times during its expected service life, and changes in chemical composition by transmutation reactions, which includes creation of reactive and insoluble gases. Fundamental materials challenges that must be resolved to effectively harness fusion power include (1) understanding the relationships between material strength, ductility and resistance to cracking, (2) development of materials with extraordinary phase stability, high-temperature strength and resistance to radiation damage, (3) establishment of the means to control corrosion of materials exposed to aggressive environments, (4) development of technologies for large-scale fabrication and joining, and (5) design of structural materials that provide for an economically attractive fusion power system while simultaneously achieving safety and environmental acceptability goals. The most effective approach to solve these challenges is a science-based effort that couples development of physics-based, predictive models of materials behavior with key experiments to validate the models. The U.S. Fusion Materials Sciences program is engaged in an integrated effort of theory, modeling and experiments to develop structural materials that will enable fusion to reach its safety, environmental and economic competitiveness goals. In this presentation, an overview of recent progress on reduced activation ferritic/martensitic steels, nanocomposited ferritic alloys, and silicon carbide fiber reinforced composites for fusion applications will be given

  6. European structural materials development for fusion applications

    Energy Technology Data Exchange (ETDEWEB)

    Schaaf, B. van der E-mail: vanderschaaf@nrg-nl.com; Ehrlich, K.; Fenici, P.; Tavassoli, A.A.; Victoria, M

    2000-09-01

    Leading long term considerations for choices in the European Long Term Technology programme are the high temperature mechanical- and compatibility properties of structural materials under neutron irradiation. The degrees of fabrication process freedom are closely investigated to allow the construction of complex shapes. Another important consideration is the activation behaviour of the structural material. The ideal solution is the recycling of the structural materials after a relatively short 'cooling' period. The structural materials development in Europe has three streams. The first serves the design and construction of ITER and is closely connected to the choice made: water cooled austenitic stainless steel. The second development stream is to support the design and construction of DEMO relevant blanket modules to be tested in ITER. The helium cooled pebble bed and the water cooled liquid lithium concept rely both on RAFM steel. The goal of the third stream is to investigate the potential of advanced materials for fusion power reactors beyond DEMO. The major contending materials: SiCSiC composites, vanadium, titanium and chromium alloys hold the promise of high operating temperatures, but RAFM has also a high temperature potential applying oxide dispersion strengthening. The development of materials for fusion power application requires a high flux 14 MeV neutron source to simulate the fusion power environment.

  7. High conductivity Be-Cu alloys for fusion reactors

    International Nuclear Information System (INIS)

    Lilley, E.A.; Adachi, Takao; Ishibashi, Yoshiki

    1995-01-01

    The optimum material has not yet been identified. This will result in heat from plasma to the first wall and divertor. That is, because of cracks and melting by thermal power and shock. Today, it is considered to be some kinds of copper, alloys, however, for using, it must have high conductivity. And it is also needed another property, for example, high strength and so on. We have developed some new beryllium copper alloys with high conductivity, high strength, and high endurance. Therefore, we are introducing these new alloys as suitable materials for the heat sink in fusion reactors

  8. Electronic structure of alloys

    International Nuclear Information System (INIS)

    Ehrenreich, H.; Schwartz, L.M.

    1976-01-01

    The description of electronic properties of binary substitutional alloys within the single particle approximation is reviewed. Emphasis is placed on a didactic exposition of the equilibrium properties of the transport and magnetic properties of such alloys. Topics covered include: multiple scattering theory; the single band alloy; formal extensions of the theory; the alloy potential; realistic model state densities; the s-d model; and the muffin tin model. 43 figures, 3 tables, 151 references

  9. Advanced smart tungsten alloys for a future fusion power plant

    Science.gov (United States)

    Litnovsky, A.; Wegener, T.; Klein, F.; Linsmeier, Ch; Rasinski, M.; Kreter, A.; Tan, X.; Schmitz, J.; Mao, Y.; Coenen, J. W.; Bram, M.; Gonzalez-Julian, J.

    2017-06-01

    The severe particle, radiation and neutron environment in a future fusion power plant requires the development of advanced plasma-facing materials. At the same time, the highest level of safety needs to be ensured. The so-called loss-of-coolant accident combined with air ingress in the vacuum vessel represents a severe safety challenge. In the absence of a coolant the temperature of the tungsten first wall may reach 1200 °C. At such a temperature, the neutron-activated radioactive tungsten forms volatile oxide which can be mobilized into atmosphere. Smart tungsten alloys are being developed to address this safety issue. Smart alloys should combine an acceptable plasma performance with the suppressed oxidation during an accident. New thin film tungsten-chromium-yttrium smart alloys feature an impressive 105 fold suppression of oxidation compared to that of pure tungsten at temperatures of up to 1000 °C. Oxidation behavior at temperatures up to 1200 °C, and reactivity of alloys in humid atmosphere along with a manufacturing of reactor-relevant bulk samples, impose an additional challenge in smart alloy development. First exposures of smart alloys in steady-state deuterium plasma were made. Smart tungsten-chroimium-titanium alloys demonstrated a sputtering resistance which is similar to that of pure tungsten. Expected preferential sputtering of alloying elements by plasma ions was confirmed experimentally. The subsequent isothermal oxidation of exposed samples did not reveal any influence of plasma exposure on the passivation of alloys.

  10. Application of vanadium alloys to a fusion reactor blanket

    Energy Technology Data Exchange (ETDEWEB)

    Bethin, J.; Tobin, A. (Grumman Aerospace Corp., Bethpage, NY (USA). Research and Development Center)

    1984-05-01

    Vanadium and vanadium alloys are of interest in fusion reactor blanket applications due to their low induced radioactivity and outstanding elevated temperature mechanical properties during neutron irradiation. The major limitation to the use of vanadium is its sensitivity to oxygen impurities in the blanket environment, leading to oxygen embrittlement. A quantitative analysis was performed of the interaction of gaseous impurities in a helium coolant with vanadium and the V-15Cr-5Ti alloy under conditions expected in a fusion reactor blanket. It was shown that the use of unalloyed V would impose severe restrictions on the helium gas cleanup system due to excessive oxygen buildup and embrittlement of the metal. However, internal oxidation effects and the possibly lower terminal oxygen solubility in the alloy would impose much less severe cleanup constraints. It is suggested that V-15Cr-5Ti is a promising candidate for certain blanket applications and deserves further consideration.

  11. Experimental Investigation of Ternary Alloys for Fusion Breeding Blankets

    Energy Technology Data Exchange (ETDEWEB)

    Choi, B. William [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chiu, Ing L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-10-26

    Future fusion power plants based on the deuterium-tritium (DT) fuel cycle will be required to breed the T fuel via neutron reactions with lithium, which will be incorporated in a breeding blanket that surrounds the fusion source. Recent work by LLNL proposed the used of liquid Li as the breeder in an inertial fusion energy (IFE) power plant. Subsequently, an LDRD was initiated to develop alternatives ternary alloy liquid metal breeders that have reduced chemical reactivity with water and air compared to pure Li. Part of the work plan was to experimentally investigate the phase diagrams of ternary alloys. Of particular interest was measurement of the melt temperature, which must be low enough to be compatible with the temperature limits of the steel used in the construction of the chamber and heat transfer system.

  12. Structure information from fusion barriers

    Indian Academy of Sciences (India)

    Pb, using the coupled reaction channel (CRC) method and correct structure information, have been analysed. The barrier distributions derived from these excitation functions including many of the significant channels are featureless, although these channels have considerable effects on the fusion excitation function.

  13. Fusion technology for the production of PbLi eutectic alloys; Obtencion de aleaciones eutecticas PbLi mediante procesos de fusion

    Energy Technology Data Exchange (ETDEWEB)

    Barrena, M. J.; Gomez de Salazar, J. M.; Quinones, J.; Pascual, L.; Soria, A.

    2012-07-01

    The development of thermonuclear experimental reactor (ITER), whose objective is to produce energy from nuclear fusion, has raised the study of Pb-Li eutectic alloys, as they have been selected for the manufacture of test blanket modules (TBM). However, during the manufacturing process of the Pb-Li alloys, thermal conditions used result in a loss of litium element, which inhibits the formation of eutectic structures. In this work we have done fusion of pure lead and lithium, evaluating different process parameters to obtain Pb-Li (17 at. %) eutectic alloys. The alloys manufactured were characterized by DSC, SEM-EDX and microhardness tests. From these studies we noted that the used of an induction reactor and the process parameters optimized to obtain Pb-Li alloy allow for completely eutectic ingots and high chemical homogeneity and microstructural. (Author) 26 refs.

  14. Development of new low activation aluminum alloys for fusion devices

    International Nuclear Information System (INIS)

    Kamada, Kohji; Kakihana, Hidetake.

    1985-01-01

    As the materials for the R facility (a tokamak nuclear fusion device in the R project intended for D-T burning) in the Institute of Plasma Physics, Nagoya University, Al-4 % Mg-0.2 % Bi (5083 improved type) and Al-4 % Mg-1 % Li, aimed at low radioactivability, high electric resistance and high strength, have been developed. The results of the nuclear properties evaluation with 14 MeV neutrons and of the measurements of electric resistance and mechanical properties were satisfactory. The possibility of producing large Al-4 % Mg-1 % Li plate (1 m x 2 m x 25 mm) in the existing factory was confirmed, with the properties retained. The electric resistances were higher than those in the conventional aluminum alloys, and still with feasibility for the further improvement. General properties of the fusion aluminum alloys and the 26 Al formation in (n, 2n) reaction were studied. (Mori, K.)

  15. Structural changes in a copper alloy due to helium implantation

    International Nuclear Information System (INIS)

    Moreno, D.; Eliezer, D.

    1996-01-01

    The most suitable nuclear fusion reaction for energy production occurs between the two heavy hydrogen isotopes, deuterium and tritium. Structural materials in fusion reactors will be exposed to helium implantation over a broad range of energies. The deformation and partial exfoliation of surface layers due to hydrogen isotopes and helium contribute to the total erosion of the first wall. For this reason, one of the most important criteria in the choice of materials for the first wall of fusion reactors is the material's damage resistance. Recent advances in developing nuclear fusion reactors reveal that efficient heat removal from plasma-facing components is very important. Copper and copper alloys are considered an attractive choice for transporting such a high heat flux without thermal damage as they have high thermal conductivity. In the present study the authors report on the structural changes in a copper alloy, due to the helium implantation on the very near surface area, observed by transmission electron microscopy

  16. Nuclear structure and fusion at the barrier

    International Nuclear Information System (INIS)

    Reisdorf, W.

    1985-01-01

    A comparative study of measured fusion excitation functions in the vicinity of the barrier reveals nuclear structure effects, due in particular to the coupling of the fusion process to direct-reaction channels. (orig.)

  17. Structural thermodynamics of alloys

    CERN Document Server

    Manenc, Jack

    1973-01-01

    Technical progress has for a very long time been directly dependent on progress in metallurgy, which is itself connected with improvements in the technology of alloys. Metals are most frequently used in the form of alloys for several reasons: the quantity of pure metal in its native state in the earth's crust is very limited; pure metals must be extracted from ores which are themselves impure. Finally, the methods of treatment used lead more easily to alloys than to pure metals. The most typical case is that of iron, where a pure ore may be found, but which is the starting point for cast iron or steel, alloys of iron and carbon. In addition, the properties of alloys are in general superior to those of pure metals and modem metallurgy consists of controlling these properties so as to make them conform to the requirements of the design office. Whilst the engineer was formerly compelled to adapt his designs and constructions to the materials available, such as wood, stone, bronze, iron, cast iron and ordinary st...

  18. Research on modulated structure alloys

    International Nuclear Information System (INIS)

    Tsujimoto, Tokuzo; Saito, Kazuo; Hashimoto, Kenki

    1982-01-01

    Research was carried out for the purposes of clarifying the cause of modulated structure formation, developing the structure control method utilizing modulated structure and clarifying the suitability of modulated structure alloys as radiation damage-resisting materials. The research on structure control method encountered a difficulty in the analysis of experimental results, bu the following results were obtained in the other items. The method of solving a diffusion equation including a nonlinear term was found in course of the clarification of the cause of modulated structure formation. As a means of detecting faint unevenness in solid solution, of which the deviation of composition is a few %, the structure analysis method utilizing magnetic property was developed. This method was applied to Ni-9.6 at.% Ti alloy, and the process of expanding amplitude in composition variation in spinodal decomposition and the formation of solute atomshort region at the time of nucleation-growth were confirmed. Utilizing the high energy electron beam generated in a superhigh voltage electron microscope, electron beam irradiation experiment was carried out on precipitation hardening alloys with modulated structure. As the result, it was found that in Ni-Ti alloy, the amount of void swelling resistance showed the change with the increase of modulated structure period. (Kako, I.)

  19. Radiation effects on structural ceramics in fusion

    International Nuclear Information System (INIS)

    Hopkins, G.R.; Price, R.J.; Trester, P.W.

    1986-01-01

    Ceramics are required to serve in a conventional role as electrical and thermal insulators and dielectrics in fusion power reactors. In addition, certain ceramic materials can play a unique structural role in fusion power reactors by virtue of their very low induced radioactivity from fusion neutron capture. The aspects of safety, long-term radioactive waste management, and personnel access for maintenance and repair can all be significantly improved by applying the low-activation ceramics to the structural materials of the first-wall and blanket regions of a fusion reactor. Achievement of long service life at high structural loads and thermal stresses on the materials exposed to high-radiation doses presents a critical challenge for fusion. In this paper, we discuss radiation effects on structural ceramics for fusion application

  20. Volatility of V15Cr5Ti fusion reactor alloy

    International Nuclear Information System (INIS)

    Neilson, R.M. Jr.

    1986-01-01

    One potential hazard from the presence of activation products in fusion facilities is accidental oxidation-driven volatility of those activation products. Scoping experiments were conducted to investigate the oxidation and elemental volatility of candidate fusion reactor alloy V15Cr5Ti as a function of time, temperature, and test atmosphere. Experiments in air and in argon carrier gases containing 10 4 to 10 1 Pa (10 -1 to 10 -4 atm) oxygen were conducted to investigate the lower oxygen partial pressure limit for the formation of a low melting point (approximately 650 0 C), high volatility, oxide layer and its formation rate. Experiments to determine the elemental volatility of alloy constituents in air at temperatures of 700 0 C to greater than 1600 0 C. Some of these volatility experiments used V15Cr5Ti that was arc-remelted to incorporate small quantities (<0.1 wt. %) of Sc and Ca. Incorporation of Sc and Ca in test specimens permitted volatility measurement of radioactive constituents present only after activation of V15Cr5Ti

  1. Copper alloys for high heat flux structure applications

    International Nuclear Information System (INIS)

    Zinkle, S.J.; Fabritsiev, S.A.

    1994-01-01

    The mechanical and physical properties of copper alloys are reviewed and compared with the requirements for high heat flux structural applications in fusion reactors. High heat flux structural materials must possess a combination of high thermal conductivity and high mechanical strength. The three most promising copper alloys at the present time are oxide dispersion-strengthened copper (Cu-Al 2 O 3 ) and two precipitation-hardened copper alloys (Cu-Cr-Zr and Cu-Ni-Be). These three alloys are capable of room temperature yield strengths >400 MPa and thermal conductivities up to 350 W/m-K. All of these alloys require extensive cold working to achieve their optimum strength. Precipitation-hardened copper alloys such Cu-Cr-Zr are susceptible to softening due to precipitate overaging and recrystallization during brazing, whereas the dislocation structure in Cu-Al 2 O 3 remains stabilized during typical high temperature brazing cycles. All three alloys exhibit good resistance to irradiation-induced softening and void swelling at temperatures below 300 degrees C. The precipitation-strengthened allows typically soften during neutron irradiation at temperatures above about 300 degrees C and therefore should only be considered for applications operating at temperatures 2 O 3 ) is considered to be the best candidate for high heat flux structural applications

  2. Multiscale modeling of radiation damage in Fe-based alloys in the fusion environment

    International Nuclear Information System (INIS)

    Wirth, B.D.; Odette, G.R.; Marian, J.; Ventelon, L.; Young-Vandersall, J.A.; Zepeda-Ruiz, L.A.

    2004-01-01

    Ferritic alloys represent a technologically important class of candidate materials for fusion first wall and blanket structures. A detailed understanding of the mechanisms of defect accumulation and microstructure evolution, and the corresponding effects on mechanical properties is required to predict their in-service structural performance limits. The physical processes involved in radiation damage, and its effects on mechanical properties, are inherently multiscale and hierarchical, spanning length and time scales from the atomic nucleus to meters and picosecond to decades. In this paper, we present a multiscale modeling methodology to describe radiation effects within the fusion energy environment. Selected results from atomic scale investigation are presented, focusing on (i) the mechanisms of self-interstitial dislocation loop formation with Burgers vector of a in iron relative to vanadium, (ii) helium transport and (iii) the interaction between helium and small self-interstitial clusters in iron, and (iv) dislocation-helium bubble interactions in fcc aluminum

  3. Development of vanadium base alloys for fusion first-wall/blanket applications

    International Nuclear Information System (INIS)

    Smith, D.L.; Chung, H.M.; Loomis, B.A.; Matsui, H.; Votinov, S.; VanWitzenburg, W.

    1994-01-01

    Vanadium alloys have been identified as a leading candidate material for fusion first-wall/blanket applications. Certain vanadium alloys exhibit favorable safety and environmental characteristics, good fabricability, high temperature and heat load capability, good compatibility with liquid metals and resistance to irradiation damage effects. The current focus is on vanadium alloys with (3-5)% Cr and (3-5)% Ti with a V-4Cr-4Ti alloy as the leading candidate. Preliminary results indicate that the crack-growth rates of certain alloys are not highly sensitive to irradiation. Results from the Dynamic Helium Charging Experiment (DHCE) which simulates fusion relevant helium/dpa ratios are similar to results from neutron irradiated material. This paper presents an overview of the recent results on the development of vanadium alloys for fusion first wall/blanket applications

  4. Numerical models for the prediction of failure for multilayer fusion Al-alloy sheets

    International Nuclear Information System (INIS)

    Gorji, Maysam; Berisha, Bekim; Hora, Pavel; Timm, Jürgen

    2013-01-01

    Initiation and propagation of cracks in monolithic and multi-layer aluminum alloys, called “Fusion”, is investigated. 2D plane strain finite element simulations are performed to model deformation due to bending and to predict failure. For this purpose, fracture strains are measured based on microscopic pictures of Nakajima specimens. In addition to, micro-structure of materials is taken into account by introducing a random grain distribution over the sheet thickness as well as a random distribution of the measured yield curve. It is shown that the performed experiments and the introduced FE-Model are appropriate methods to highlight the advantages of the Fusion material, especially for bending processes

  5. Image fusion for enhanced forest structural assessment

    CSIR Research Space (South Africa)

    Roberts, JW

    2011-01-01

    Full Text Available This research explores the potential benefits of fusing active and passive medium resolution satellite-borne sensor data for forest structural assessment. Image fusion was applied as a means of retaining disparate data features relevant to modeling...

  6. Study on structural materials used in thermonuclear fusion technology

    International Nuclear Information System (INIS)

    Billa, R.; Amaral, D.

    1995-01-01

    The main problem related to the construction of a thermonuclear fusion reactor is the absence of suitable materials for the process, concerning to temperature limits, heat flux and life time. The first wall is the most critical part of the structure, being submitted to radiation effects, ionic corrosion and coolant, besides thermal fatigue and tension produced by cyclical burning. The AISI 316(17-12SPH) stainless steel is used as structural material, which has a wide known database. This work proposes an alternative material study to be used in the future thermonuclear fusion reactors. As a option a study on the utilization of Cr-Mn(Fe-17 Mn-10 Cr-0,1 C) steels and their alloy variations is presented

  7. Fusion neutron irradiation of Ni(Si) alloys at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Huang, J.S.; Guinan, M.W.; Hahn, P.A.

    1987-09-01

    Two Ni-4% Si alloys, with different cold work levels, are irradiated with 14 MeV fusion neutrons at 623 K, and their Curie temperatures are monitored during irradiation. The results are compared to those of an identical alloy irradiated by 2 MeV electrons. The results show that increasing dislocation density increases the Curie temperature change rate. At the same damage rate, the Curie temperature change rate for the alloy irradiated by 14 MeV fusion neutrons is only 6 to 7% of that for an identical alloy irradiated by 2 MeV electrons. It is well known that the migration of radiation induced defects contributes to segregation of silicon atoms at sinks in this alloy, causing the Curie temperature changes. The current results imply that the relative free defect production efficiency decreases from one for the electron irradiated sample to 6 to 7% for the fusion neutron irradiated sample. 17 refs., 4 figs., 1 tab.

  8. Fusion neutron irradiation of Ni(Si) alloys at high temperature

    International Nuclear Information System (INIS)

    Huang, J.S.; Guinan, M.W.; Hahn, P.A.

    1987-09-01

    Two Ni-4% Si alloys, with different cold work levels, are irradiated with 14 MeV fusion neutrons at 623 K, and their Curie temperatures are monitored during irradiation. The results are compared to those of an identical alloy irradiated by 2 MeV electrons. The results show that increasing dislocation density increases the Curie temperature change rate. At the same damage rate, the Curie temperature change rate for the alloy irradiated by 14 MeV fusion neutrons is only 6 to 7% of that for an identical alloy irradiated by 2 MeV electrons. It is well known that the migration of radiation induced defects contributes to segregation of silicon atoms at sinks in this alloy, causing the Curie temperature changes. The current results imply that the relative free defect production efficiency decreases from one for the electron irradiated sample to 6 to 7% for the fusion neutron irradiated sample. 17 refs., 4 figs., 1 tab

  9. Fusion neutron irradiation of Ni-Si alloys at high temperature*1

    Science.gov (United States)

    Huang, J. S.; Guinan, M. W.; Hahn, P. A.

    1988-07-01

    Two Ni-4% Si alloys, with different cold work levels, have been irradiated with 14-MeV fusion neutrons at 623 K, and their Curie temperatures have been monitored during irradiation. The results are compared to those of an identical alloy irradiated by 2-MeV electrons. The results show that increasing dislocation density increases the Curie temperature change rate. At the same damage rate, the Curie temperature change rate for the alloy irradiated by 14-MeV fusion neutrons is only 6-7% of that for an identical alloy irradiated by 2-MeV electrons. It is well known that the migration of radiation induced defects contributes to segregation of silicon atoms at sinks in this alloy, causing the Curie temperature changes. The current results imply that the relative free defect production efficiency decreases from one for the electron irradiated sample to 6-7% for the fusion neutron irradiated sample.

  10. Safety considerations of lithium lead alloy as a fusion reactor breeding material

    International Nuclear Information System (INIS)

    Jeppson, D.W.; Muhlestein, L.D.

    1985-01-01

    Test results and conclusions are presented for lithium lead alloy interactions with various gas atmospheres, concrete and potential reactor coolants. The reactions are characterized to evaluate the potential of volatilizing and transporting radioactive species associated with the liquid breeder under postulated fusion reactor accident conditions. The safety concerns identified for lithium lead alloy reactions with the above materials are compared to those previously identified for a reference fusion breeder material, liquid lithium. Conclusions made from this comparison are also included

  11. Mechanical properties and microstructure of copper alloys and copper alloy-stainless steel laminates for fusion reactor high heat flux applications

    Science.gov (United States)

    Leedy, Kevin Daniel

    A select group of copper alloys and bonded copper alloy-stainless steel panels are under consideration for heat sink applications in first wall and divertor structures of a planned thermonuclear fusion reactor. Because these materials must retain high strengths and withstand high heat fluxes, their material properties and microstructures must be well understood. Candidate copper alloys include precipitate strengthened CuNiBe and CuCrZr and dispersion strengthened Cu-Alsb2Osb3 (CuAl25). In this study, uniaxial mechanical fatigue tests were conducted on bulk copper alloy materials at temperatures up to 500sp°C in air and vacuum environments. Based on standardized mechanical properties measurement techniques, a series of tests were also implemented to characterize copper alloy-316L stainless steel joints produced by hot isostatic pressing or by explosive bonding. The correlation between mechanical properties and the microstructure of fatigued copper alloys and the interface of copper alloy-stainless steel laminates was examined. Commercial grades of these alloys were used to maintain a degree of standardization in the materials testing. The commercial alloys used were OMG Americas Glidcop CuAl25 and CuAl15; Brush Wellman Hycon 3HP and Trefimetaux CuNiBe; and Kabelmetal Elbrodur and Trefimetaux CuCrZr. CuAl25 and CuNiBe alloys possessed the best combination of fatigue resistance and microstructural stability. The CuAl25 alloy showed only minimal microstructural changes following fatigue while the CuNiBe alloy consistently exhibited the highest fatigue strength. Transmission electron microscopy observations revealed that small matrix grain sizes and high densities of submicron strengthening phases promoted homogeneous slip deformation in the copper alloys. Thus, highly organized fatigue dislocation structure formation, as commonly found in oxygen-free high conductivity Cu, was inhibited. A solid plate of CuAl25 alloy hot isostatically pressed to a 316L stainless steel

  12. Progress in the development of the blanket structural material for fusion reactors

    International Nuclear Information System (INIS)

    Scott, J.L.; Bloom, E.E.; Grossbeck, M.L.; Maziasz, P.J.; Wiffen, F.W.; Gold, R.E.; Holmes, J.J.; Reuther, P.C. Jr.; Rosenwasser, S.N.

    1981-01-01

    The Alloy Development for Irradiation Performance Program has become more focused since the last Fusion Reactor Technology Conference two years ago. Since austenitic stainless steels and ferritic steels are candidate structural materials for the near-term reactors ETF and INTOR and austenitic stainless steel is also the preferred structural material for the steady-state commercial fusion reactor, STARFIRE, a vigorous experimental program is under way to identify the best alloy from each of these alloy classes and to provide the engineering data base in a timely manner. In addition the comprehensive program that includes high-strength Fe-Ni-Cr alloys, reactive and refractory metals, and advanced concepts continues in an orderly fashion

  13. Flow and fracture of alloys in the fusion environment

    International Nuclear Information System (INIS)

    Wolfer, W.G.

    1982-01-01

    The present paper examines both ductile and brittle fracture models of steels and assesses the impact of the fusion reactor environment on the fracture processes. In particular, the connections between plastic flow properties and fracture modes are reviewed for both ductile and brittle crack propagation. Highly radiation-hardened materials exhibit extreme flow location resulting in channel fracture. Physical models for this phenomon are developed and an estimate for the associated fracture toughness is given. The impact of radiation-hardening and ductility loss on fatigue crack growth is examined. Next, models describing the chemical effects on fatigue and fracture are briefly discussed. Finally, fracture design criteria are proposed for first wall structures in fusion reactors. (orig.)

  14. Powder Metallurgy Processing of a WxTaTiVCr High-Entropy Alloy and Its Derivative Alloys for Fusion Material Applications.

    Science.gov (United States)

    Waseem, Owais Ahmed; Ryu, Ho Jin

    2017-05-16

    The W x TaTiVCr high-entropy alloy with 32at.% of tungsten (W) and its derivative alloys with 42 to 90at.% of W with in-situ TiC were prepared via the mixing of elemental W, Ta, Ti, V and Cr powders followed by spark plasma sintering for the development of reduced-activation alloys for fusion plasma-facing materials. Characterization of the sintered samples revealed a BCC lattice and a multi-phase structure. The selected-area diffraction patterns confirmed the formation of TiC in the high-entropy alloy and its derivative alloys. It revealed the development of C15 (cubic) Laves phases as well in alloys with 71 to 90at.% W. A mechanical examination of the samples revealed a more than twofold improvement in the hardness and strength due to solid-solution strengthening and dispersion strengthening. This study explored the potential of powder metallurgy processing for the fabrication of a high-entropy alloy and other derived compositions with enhanced hardness and strength.

  15. Composites as structural materials in fusion reactors

    International Nuclear Information System (INIS)

    Megusar, J.

    1989-01-01

    In fusion reactors, materials are used under extreme conditions of temperature, stress, irradiation, and chemical environment. The absence of adequate materials will seriously impede the development of fusion reactors and might ultimately be one of the major difficulties. Some of the current materials problems can be solved by proper design features. For others, the solution will have to rely on materials development. A parallel and balanced effort between the research in plasma physics and fusion-related technology and in materials research is, therefore, the best strategy to ultimately achieve economic, safe, and environmentally acceptable fusion. The essential steps in developing composites for structural components of fusion reactors include optimization of mechanical properties followed by testing under fusion-reactor-relevant conditions. In optimizing the mechanical behavior of composite materials, a wealth of experience can be drawn from the research on ceramic matrix and metal matrix composite materials sponsored by the Department of Defense. The particular aspects of this research relevant to fusion materials development are methodology of the composite materials design and studies of new processing routes to develop composite materials with specific properties. Most notable examples are the synthesis of fibers, coatings, and ceramic materials in their final shapes form polymeric precursors and the infiltration of fibrous preforms by molten metals

  16. Path E alloys: ferritic material development for magnetic fusion energy applications

    International Nuclear Information System (INIS)

    Holmes, J.J.

    1980-09-01

    The application of ferritic materials in irradiation environments has received greatly expanded attention in the last few years, both internationally and in the United States. Ferritic materials are found to be resistant to irradiation damage and have in many cases superior properties to those of AISI 316. It has been shown that for magnetic fusion energy applications the low thermal expansion behavior of the ferritic alloy class will result in lower thermal stresses during reactor operation, leading to significantly longer ETF operating lifetimes. The Magnetic Fusion Energy Program therefore now includes a ferritic alloy option for alloy selection and this option has been designated Path E

  17. Performance characteristics of shape memory alloy and its applications for fusion technology

    International Nuclear Information System (INIS)

    Nishikawa, Masahiro; Watanabe, Kenji

    1987-01-01

    As a shape memory alloy, Au-Cd alloy was found in 1951. Thereafter, also in In-Tl alloy, shape memory effect was found. The U.S. Naval Ordinance Laboratory developed Ni-Ti alloy, and published in 1965 as NITINOL. As Cu group shape memory alloys, there are Cu-Zn-Al alloy, Cu-Al-Be alloy and Cu-Al-Ni alloy. Recently, iron group shape memory alloy was published. In 1975, 'Shape memory effect and its application' symposium, in 1978, 'NITINOL heat engine international conference', and in 1982 and 1986, 'Martensite transformation international conference' were held, and the method of the proper use of shape memory alloys and the problems of the alloys themselves such as fatigue have been gradually clarified. In this report, the fundamental action characteristics of shape memory alloys are discribed from the viewpoint of the application, and the possibility of applying these characteristics to nuclear fusion devices and the advantage obtained as the result are explained. Shape memory effect and pseudo-elasticity, reversible shape memory effect, the thermodynamic behavior of shape memory alloys, transformation temperature range and using temperature range and so on are described. (Kako, I.)

  18. Nuclear structure and heavy-ion fusion

    International Nuclear Information System (INIS)

    Stokstad, R.G.

    1980-10-01

    A series of lectures is presented on experimental studies of heavy-ion fusion reactions with emphasis on the role of nuclear structure in the fusion mechanism. The experiments considered are of three types: the fusion of lighter heavy ions at subcoulomb energies is studied with in-beam γ-ray techniques; the subbarrier fusion of 16 O and 40 Ar with the isotopes of samarium is detected out of beam by x-radiation from delayed activity; and measurements at very high energies, again for the lighter ions, employ direct particle identification of evaporation residues. The experimental data are compared with predictions based on the fusion of two spheres with the only degree of freedom being the separation of the centers, and which interact via potentials that vary smoothly with changes in the mass and charge of the projectile and target. The data exhibit with the isotopes of samarium, a portion of these deviations can be understood in terms of the changing deformation of the target nucleus, but an additional degree of freedom such as neck formation appears necessary. The results on 10 B + 16 O and 12 C + 14 N → 26 Al at high bombarding energies indicate a maximum limiting angular momentum characteristic of the compound nucleus. At lower energies the nuclear structure of the colliding ion seems to affect strongly the cross section for fusion. Measurements made at subbarrier energies for a variety of projectile-target combinations in the 1p and 2s - 1d shell also indicate that the valence nucleons can affect the energy dependence for fusion. About half the systems studied so far have structureless excitation functions which follow a standard prediction. The other half exhibit large variations from this prediction. The possible importance of neutron transfer is discussed. The two-center shell model appears as a promising approach for gaining a qualitative understanding of these phenomena. 95 references, 52 figures, 1 table

  19. Investigation on the radiation damage behavior of various alloys in a fusion reactor using thorium molten salt

    International Nuclear Information System (INIS)

    Ubeyli, Mustafa; Demir, Teyfik

    2008-01-01

    In fusion reactors, one of the most important problems is the need for the frequent change of the first wall material during the reactor's operation due to the radiation damage induced by high energetic particles, especially fusion neutrons coming from fusion plasma. In order to solve this problem, in HYLIFE-II fusion reactor design, a liquid wall between the fusion plasma and first wall is used. This study presents the radiation damage behaviors of candidate structural materials (9Cr-2WVTa, V-4Cr-4Ti and W-5Re alloys) considered to be used in fusion reactors to determine the optimum thickness of the liquid wall in HYLIFE-II fusion reactor. In the liquid wall, a thorium molten salt consisting of 75%LiF-23%ThF 4 -2% 233 UF 4 was used. Calculations were carried out with respect to the variable liquid wall thickness and for an operation period of 30 years. Numerical results related to atomic displacement and helium generation damage pointed out that the liquid wall thickness should be at least 42, 66 and 81 cm for the materials, W-5Re, 9Cr-2WVTa, V-4Cr-4Ti, respectively in order not to exceed relevant damage limits after a reactor operation of 30 years

  20. Activation and clearance of vanadium alloys and beryllium multipliers in fusion reactors

    International Nuclear Information System (INIS)

    Bartenev, S.; Romanovskij, V.; Ciampichetti, A.; Zucchetti, M.; Forrest, R.; Kolbasov, B.; Romanov, P.

    2006-01-01

    Design of fusion reactors includes the development of low-activation materials. V-Cr-Ti alloys are among the candidate structural materials for the first wall and blanket, with the scarce and costly V as the main component. It is worth considering its regeneration and refabrication as well as to avoid its disposal as radioactive waste. However, to do so, it is necessary to bring its radioactivity down to sufficiently low levels. We have two possible goals: · Recycling (within the nuclear industry) for first wall and front blanket components. In that case, contact dose rate must be sufficiently low. · Clearance (release from nuclear regulatory control) for back blanket and backplate components. In that case, the clearance index must be below unity. In fact, for components less exposed to neutron activation, clearance may be reachable, after a conceivable period of decay. Maximum radionuclide concentrations in the alloys allowing their clearance were determined, using new IAEA Clearance Limits. For this purpose, also for less neutron-exposed structures, such as the back part of the blanket and the backplate, clearance is possible only if certain activation products are separated. As for recycling within the nuclear industry of first wall components, also for clearance it turns out that the development of isotope chemical separation techniques is interesting and necessary for our purposes. A suitable method for achieving the required substantial radioactivity reduction of activated V-Cr-Ti alloys is radiochemical extraction reprocessing, Such a technology, permitting to remove metallic activation products from spent materials, was developed and tested experimentally in Russia. Concerning clearance of less activated components, based on the estimated element distribution factors in the extraction and re-extraction processes, and computations, it was shown that the alloy components may be purified from the activation products, using this technology, down to an

  1. Nickel aluminide alloy suitable for structural applications

    Science.gov (United States)

    Liu, C.T.

    1998-03-10

    Alloys are disclosed for use in structural applications based upon NiAl to which are added selected elements to enhance room temperature ductility and high temperature strength. Specifically, small additions of molybdenum produce a beneficial alloy, while further additions of boron, carbon, iron, niobium, tantalum, zirconium and hafnium further improve performance of alloys at both room temperature and high temperatures. A preferred alloy system composition is Ni--(49.1{+-}0.8%)Al--(1.0{+-}0.8%)Mo--(0.7 + 0.5%)Nb/Ta/Zr/Hf--(nearly zero to 0.03%)B/C, where the % is at. % in each of the concentrations. All alloys demonstrated good oxidation resistance at the elevated temperatures. The alloys can be fabricated into components using conventional techniques. 4 figs.

  2. Structural features in Ni-Al alloys

    International Nuclear Information System (INIS)

    Abylkalykova, R.B.; Kveglis, L.I.; Rakhimova, U.A.; Nasokhova, Sh.B.; Tazhibaeva, G.B.

    2007-01-01

    Purpose of the work is study of structural transformations under diverse memory effect in Ni-Al alloys. Examination were conducted in following composition samples: Ni -75 at.% and Al - 25 at.%. The work is devoted to clarification reasons both formation atom-ordered structures in inter-grain boundaries of bulk samples under temperature action and static load. Revealed inter-grain inter-boundary layers in Ni-Al alloy both bulk and surface state have complicated structure

  3. Structural materials for fusion and spallation sources

    International Nuclear Information System (INIS)

    Cottrell, G.A.; Baker, L.J.

    2003-01-01

    Experimental investigation of neutron-induced irradiation damage in structural materials is fundamental to the development of magnetic confinement fusion. Proposals for the testing of candidate materials are described, indicating that a period of at least 10 years will elapse before a suitable high neutron fluence fusion test facility becomes available. In this circumstance, the possibility that neutron spallation sources could be exploited to shorten the time-scale of fusion materials development is attractive. Although fusion displacement and transmutation reaction rates can be replicated in spallation sources, there are significant differences arising from the harder neutron spectra and the presence of energetic protons. These differences, including higher energy PKA, electron heating effects, transmutation rates and pulsing are described and their consequences discussed, together with the concomitant development of theoretical models, needed to understand the effects. It is concluded that spallation source experiments could make a significant contribution to the database required for the validation of theoretical models, and hence reduce the time scale of fusion materials development

  4. Structural alloys for high field superconducting magnets

    International Nuclear Information System (INIS)

    Morris, J.W. Jr.

    1985-08-01

    Research toward structural alloys for use in high field superconducting magnets is international in scope, and has three principal objectives: the selection or development of suitable structural alloys for the magnet support structure, the identification of mechanical phenomena and failure modes that may influence service behavior, and the design of suitable testing procedures to provide engineering design data. This paper reviews recent progress toward the first two of these objectives. The structural alloy needs depend on the magnet design and superconductor type and differ between magnets that use monolithic and those that employ force-cooled or ICCS conductors. In the former case the central requirement is for high strength, high toughness, weldable alloys that are used in thick sections for the magnet case. In the latter case the need is for high strength, high toughness alloys that are used in thin welded sections for the conductor conduit. There is productive current research on both alloy types. The service behavior of these alloys is influenced by mechanical phenomena that are peculiar to the magnet environment, including cryogenic fatigue, magnetic effects, and cryogenic creep. The design of appropriate mechanical tests is complicated by the need for testing at 4 0 K and by rate effects associated with adiabatic heating during the tests. 46 refs

  5. Study on a multi-component palladium alloy membrane for the fusion fuel cycle

    International Nuclear Information System (INIS)

    Yoshida, Hiroshi; Okuno, Kenji; Nagasaki, Takanori; Noda, Kenji; Ishii, Yoshinobu; Takeshita, Hidefumi.

    1985-11-01

    A feasibility study on the material integrity with respect to the hydride formation and helium damage of the palladium alloy membrane was performed for an application of the palladium diffuser to a fusion fuel cleanup process. This study was conducted under the Japan/US Fusion Cooperation Program. Experimental works on the crystallography, hydrogen solubility and 3 He release characteristics were carried out with a multi-component palladium alloy(Pd-25Ag.Au.Ru). The excellent hydrogen permeability and mechanical properties of the membrane made of this alloy had been confirmed by authors' previous study. Based on the present study, this alloy membrane has high resistivity to the hydrogen embrittlement, and swelling and fracture due to the helium bubble formation under the practical operating conditions of the diffuser. (author)

  6. Some experiments on cold fusion by deuterium hydrogen gas infusion in titanium metal alloy

    International Nuclear Information System (INIS)

    Mestnik Filho, J.; Geraldo, L.P.; Pugliese, R.; Saxena, R.N.; Morato, S.P.; Fulfaro, R.

    1990-05-01

    New results on cold fusion are reported where three different experimental situations have been tried: a) deuterium gas loaded titanium; b) deuterium gas loaded Ti 0.8 Zr 0.2 CrMn alloy and c) titanium and the Ti 0.8 Zr 0.2 CrMn alloy loaded with a mixture of deuterium and hydrogen gases. With these experiments, new thermodynamical non equilibrium conditions were achieved and the possibility of cold fusion between protons and deuterons was also tested. Three independent neutron detectors and one NaI(Tl) were utilized. Despite some large values reported in the literature for the fusion rate, an upper limit of only 8 x 10 -24 fusions/sper deuterium pair or per deuterium-hydrogen pair was determined within the attained accuracy. (author) [pt

  7. Structure Map for Embedded Binary Alloy Nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, C.W.; Shin, S.J.; Liao, C.Y.; Guzman, J.; Stone, P.R.; Watanabe, M.; Ager III, J.W.; Haller, E.E.; Chrzan, D.C.

    2008-09-20

    The equilibrium structure of embedded nanocrystals formed from strongly segregating binary-alloys is considered within a simple thermodynamic model. The model identifies two dimensionlessinterface energies that dictate the structure, and allows prediction of the stable structure for anychoice of these parameters. The resulting structure map includes three distinct nanocrystal mor-phologies: core/shell, lobe/lobe, and completely separated spheres.

  8. Composition Optimization of Lithium-Based Ternary Alloy Blankets for Fusion Reactors

    Science.gov (United States)

    Jolodosky, Alejandra

    The goal of this dissertation is to examine the neutronic properties of a novel type of fusion reactor blanket material in the form of lithium-based ternary alloys. Pure liquid lithium, first proposed as a blanket for fusion reactors, is utilized as both a tritium breeder and a coolant. It has many attractive features such as high heat transfer and low corrosion properties, but most importantly, it has a very high tritium solubility and results in very low levels of tritium permeation throughout the facility infrastructure. However, lithium metal vigorously reacts with air and water and presents plant safety concerns including degradation of the concrete containment structure. The work of this thesis began as a collaboration with Lawrence Livermore National Laboratory in an effort to develop a lithium-based ternary alloy that can maintain the beneficial properties of lithium while reducing the reactivity concerns. The first studies down-selected alloys based on the analysis and performance of both neutronic and activation characteristics. First, 3-D Monte Carlo calculations were performed to evaluate two main neutronics performance parameters for the blanket: tritium breeding ratio (TBR), and energy multiplication factor (EMF). Alloys with adequate results based on TBR and EMF calculations were considered for activation analysis. Activation simulations were executed with 50 years of irradiation and 300 years of cooling. It was discovered that bismuth is a poor choice due to achieving the highest decay heat, contact dose rates, and accident doses. In addition, it does not meet the waste disposal ratings (WDR). The straightforward approach to obtain Monte Carlo TBR and EMF results required 231 simulations per alloy and became computationally expensive, time consuming, and inefficient. Consequently, alternate methods were pursued. A collision history-based methodology recently developed for the Monte Carlo code Serpent, calculates perturbation effects on practically

  9. Optimum alloy compositions in reduced-activation martensitic 9Cr steels for fusion reactor

    International Nuclear Information System (INIS)

    Abe, F.; Noda, T.; Okada, M.

    1992-01-01

    In order to obtain potential reduced-activation ferritic steels suitable for fusion reactor structures, the effect of alloying elements W and V on the microstructural evolution, toughness, high-temperature creep and irradiation hardening behavior was investigated for simple 9Cr-W and 9Cr-V steels. The creep strength of the 9Cr-W steels increased but their toughness decreased with increasing W concentration. The 9Cr-V steels exhibited poor creep rupture strength, far below that of a conventional 9Cr-1MoVNb steel and poor toughness after aging at 873 K. It was also found that the Δ-ferrite should be avoided, because it degraded both the roughness and high-temperature creep strength. Based on the results on the simple steels, optimized martensitic 9Cr steels were alloy-designed from a standpoint of enough thoughness and high-temperature creep strength. Two kinds of optimized 9Cr steels with low and high levels of W were obtained; 9Cr-1WVTa and 9Cr-3WVTa. These steels indeed exhibited excellent toughness and creep strength, respectively. The 9Cr-1WVTa steel exhibiting an excellent roughness was shown to be the most promising for relatively low-temperature application below 500deg C, where irradiation embrittlement is significant. The 9Cr-3WVTa steel was the most promising for high temperature application above 500deg C from the standpoint of enough high-temperature strength. (orig.)

  10. Probing heat transfer, fluid flow and microstructural evolution during fusion welding of alloys

    Science.gov (United States)

    Zhang, Wei

    The composition, geometry, structure and properties of the welded joints are affected by the various physical processes that take place during fusion welding. Understanding these processes has been an important goal in the contemporary welding research to achieve structurally sound and reliable welds. In the present thesis research, several important physical processes including the heat transfer, fluid flow and microstructural evolution in fusion welding were modeled based on the fundamentals of transport phenomena and phase transformation theory. The heat transfer and fluid flow calculation is focused on the predictions of the liquid metal convection in the weld pool, the temperature distribution in the entire weldment, and the shape and size of the fusion zone (FZ) and heat affected zone (HAZ). The modeling of microstructural evolution is focused on the quantitative understanding of phase transformation kinetics during welding of several important alloys under both low and high heating and cooling conditions. Three numerical models were developed in the present thesis work: (1) a three-dimensional heat transfer and free surface flow model for the gas metal arc (GMA) fillet welding considering the complex weld joint geometry, (2) a phase transformation model based on the Johnson-Mehl-Avrami (JMA) theory, and (3) a one-dimensional numerical diffusion model considering multiple moving interfaces. To check the capabilities of the developed models, several cases were investigated, in which the predictions from the models were compared with the experimental results. The cases studied are the follows. For the modeling of heat transfer and fluid flow, the welding processes studied included gas tungsten arc (GTA) linear welding, GTA transient spot welding, and GMA fillet welding. The calculated weldment geometry and thermal cycles was validated against the experimental data under various welding conditions. For the modeling of microstructural evolution, the welded

  11. The effect of low energy helium ion irradiation on tungsten-tantalum (W-Ta) alloys under fusion relevant conditions

    Science.gov (United States)

    Gonderman, S.; Tripathi, J. K.; Novakowski, T. J.; Sizyuk, T.; Hassanein, A.

    2017-08-01

    Currently, tungsten remains the best candidate for plasma-facing components (PFCs) for future fusion devices because of its high melting point, low erosion, and strong mechanical properties. However, continued investigation has shown tungsten to undergo severe morphology changes under fusion-like conditions. These results motivate the study of innovative PFC materials which are resistant to surface morphology evolution. The goal of this work is to examine tungsten-tantalum (W-Ta) alloys, a potential PFC material, and their response to low energy helium ion irradiation. Specifically, W-Ta samples are exposed to 100 eV helium irradiations with a flux of 1.15 × 1021 ions m-2 s-1, at 873 K, 1023 K, and 1173 K for 1 h duration. Scanning electron microscopy (SEM) reveals significant changes in surface deterioration due to helium ion irradiation as a function of both temperature and tantalum concentration in W-Ta samples. X-Ray Diffraction (XRD) studies show a slight lattice parameter expansion in W-Ta alloy samples compared to pure W samples. The observed lattice parameter expansion in W-Ta alloy samples (proportional to increasing Ta wt.% concentrations) reflect significant differences observed in the evolution of surface morphology, i.e., fuzz development processes for both increasing Ta wt.% concentration and target temperature. These results suggest a correlation between the observed morphology differences and the induced crystal structure change caused by the presence of tantalum. Shifts in the XRD peaks before and after 100 eV helium irradiation with a flux of 1.15 × 1021 ions m-2 s-1, 1023 K, for 1 h showed a significant difference in the magnitude of the shift. This has suggested a possible link between the atomic spacing of the material and the accumulated damage. Ongoing research is needed on W-Ta alloys and other innovative materials for their application as irradiation resistant materials in future fusion or irradiation environments.

  12. Structure of Zr-Hf alloys

    International Nuclear Information System (INIS)

    Dobromyslov, A.V.; Taluts, N.I.

    1991-01-01

    Structure of quenched zirconium-hafnium alloy system containing up to 2.5 at. % was studied. Existence of three morphological forms of α-phase was presented: lath, twinned, laminated. Twinning plane in the system was identified. Formation model of packet structure of lath martensite was suggested

  13. Low activation structural material candidates for fusion power plants

    International Nuclear Information System (INIS)

    Forty, C.B.A.; Cook, I.

    1997-06-01

    Under the SEAL Programme of the European Long-Term Fusion Safety Programme, an assessment was performed of a number of possible blanket structural materials. These included the steels then under consideration in the European Blanket Programme, as well as materials being considered for investigation in the Advanced Materials Programme. Calculations were performed, using SEAFP methods, of the activation properties of the materials, and these were related, based on the SEAFP experience, to assessments of S and E performance. The materials investigated were the SEAFP low-activation martensitic steel (LA12TaLC); a Japanese low-activation martensitic steel (F-82H), a range of compositional variants about this steel; the vanadium-titanium-chromium alloy which was the original proposal of the ITER JCT for the ITER in-vessel components; a titanium-aluminium intermetallic (Ti-Al) which is under investigation in Japan; and silicon carbide composite (SiC). Assessed impurities were included in the compositions of these materials, and they have very important impacts on the activation properties. Lack of sufficiently detailed data on the composition of chromium alloys precluded their inclusion in the study. (UK)

  14. Hydrogen formation in metals and alloys during fusion reactor operation

    International Nuclear Information System (INIS)

    Zimin, S.; Takatsu, Hideyuki; Mori, Seiji

    1994-08-01

    The results of neutron transport calculations of the hydrogen formation based on the JENDL gas-production cross section file are discussed for some metals and alloys, namely 51 V, Cr, Fe, Ni, Mo, austenitic stainless steel (Ti modified 316SS:PCA), ferritic steel (Fe-8Cr-2W:F82H) and the vanadium-base alloy (V-5Cr-5Ti). Impact of the steel fraction in steel/water homogeneous blanket/shield compositions on the hydrogen formation rate in above-mentioned metals and alloys is discussed both for the hydrogen formation in the first wall and the blanket/shield components. The results obtained for the first wall are compared with those for the helium formation obtained at JAERI by the same calculational conditions. Hydrogen formation rates at the first wall having 51 V, Cr, Fe, Ni and Mo are larger than those of helium by 3-8 times. (author)

  15. Thermal Aging Effect on Corrosion Resistance in Fusion Boundary of A533 Gr. B and Alloy 152

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kyoung Joon; Yoo, Seung Chang; Kim, Taeho; Ham, Junhyuk; Kim, Ji Hyun [UNIST, Ulsan (Korea, Republic of)

    2016-10-15

    Dissimilar metal weldment (DMW) is frequently used for joining low-alloy steel pressure vessel nozzles and steam generator nozzles to nickel-based wrought alloy or austenitic stainless steel components in high energy systems. This feature also significantly hinders C diffusion from the ferrite base metal to the weld metal. Until now, stress corrosion cracking has not occurred in DMWs where a High-Cr weld metal (such as Alloy 152 or Alloy 690), which is Ni-base weld metal including relative high Cr, is used as the weld metal in the weld between the nickel-based alloy and low-alloy steel. To understand the microstructure and corrosion evolution on fusion boundary between low-alloy steel and Ni-base weld metal, microstructural analysis and polarization test were performed with A533 Gr. B/Alloy 152/Alloy 690. Remarkable changes were observed in corrosion resistance and hardness at fusion boundary between low-alloy steel and Ni-base weld metal. The precipitate, which has different potential with peripheral region, can cause galvanic corrosion or pitting corrosion and is the one of hardening methods by disturbing movement of the dislocation. At initial step of heat treatment, the number of precipitates was increased. In fusion boundary between A533 Gr. B and Alloy 152, the corrosion resistance was decreased, and the hardness was increased. Next, at further step, the number of precipitates.

  16. Activation and Radiation Damage Behaviour of Russian Structural Materials for Fusion Reactors in the Fission and Fusion Reactors

    International Nuclear Information System (INIS)

    Blokhin, A.; Demin, N.; Chernov, V.; Leonteva-Smirnova, M.; Potapenko, M.

    2006-01-01

    Various structural low (reduced) activated materials have been proposed as a candidate for the first walls-blankets of fusion reactors. One of the main problems connected with using these materials - to minimise the production of long-lived radionuclides from nuclear transmutations and to provide with good technological and functional properties. The selection of materials and their metallurgical and fabrication technologies for fusion reactor components is influenced by this factor. Accurate prediction of induced radioactivity is necessary for the development of the fusion reactor materials. Low activated V-Ti-Cr alloys and reduced activated ferritic-martensitic steels are a leading candidate material for fusion first wall and blanket applications. At the present time a range of compositions and an impurity level are still being investigated to better understand the sensitive of various functional and activation properties to small compositional variations and impurity level. For the two types of materials mentioned above (V-Ti-Cr alloys and 9-12 % Cr f/m steels) and manufactured in Russia (Russia technologies) the analysis of induced activity, hydrogen and helium-production as well as the accumulation of such elements as C, N, O, P, S, Zn and Sn as a function of irradiation time was performed. Materials '' were irradiated '' by fission (BN-600, BOR-60) and fusion (Russian DEMO-C Reactor Project) typical neutron spectra with neutron fluency up to 10 22 n/cm 2 and the cooling time up to 1000 years. The calculations of the transmutation of elements and the induced radioactivity were carried out using the FISPACT inventory code, and the different activation cross-section libraries like the ACDAM, FENDL-2/A and the decay data library FENDL-2/D. It was shown that the level of impurities controls a long-term behaviour of induced activity and contact dose rate for materials. From this analysis the concentration limits of impurities were obtained. The generation of gas

  17. Powder metallurgical processing of self-passivating tungsten alloys for fusion first wall application

    International Nuclear Information System (INIS)

    López-Ruiz, P.; Ordás, N.; Iturriza, I.; Walter, M.; Gaganidze, E.; Lindig, S.; Koch, F.; García-Rosales, C.

    2013-01-01

    Self-passivating tungsten based alloys are expected to provide a major safety advantage compared to pure tungsten, presently the main candidate material for first wall armour of future fusion reactors. In case of a loss of coolant accident with simultaneous air ingress, a protective oxide scale will be formed on the surface of W avoiding the formation of volatile and radioactive WO 3 . Bulk WCr12Ti2.5 alloys were manufactured by mechanical alloying (MA) and hot isostatic pressing (HIP), and their properties compared to bulk WCr10Si10 alloys from previous work. The MA parameters were adjusted to obtain the best balance between lowest possible amount of contaminants and effective alloying of the elemental powders. After HIP, a density >99% is achieved for the WCr12Ti2.5 alloy and a very fine and homogeneous microstructure with grains in the submicron range is obtained. Unlike the WCr10Si10 material, no intergranular ODS phase inhibiting grain growth was detected. The thermal and mechanical properties of the WCr10Si10 material are dominated by the silicide (W,Cr) 5 Si 3 ; it shows a sharp ductile-to brittle transition in the range 1273–1323 K. The thermal conductivity of the WCr12Ti2.5 alloy is close to 50 W/mK in the temperature range of operation; it exhibits significantly higher strength and lower DBTT – around 1170 K – than the WCr10Si10 material

  18. Examination of the effect of Sc on 2000 and 7000 series aluminium alloy castings: for improvements in fusion welding

    International Nuclear Information System (INIS)

    Norman, A.F.; Hyde, K.; Costello, F.; Thompson, S.; Birley, S.; Prangnell, P.B.

    2003-01-01

    It has been reported that small additions of scandium (Sc) can improve the weldability and mechanical properties of some aluminium aerospace alloys that are normally considered to be 'unweldable'. In order to determine the mechanisms by which these improvements occur, and more rapidly arrive at optimum Sc addition levels, small wedge-shaped castings have been used to simulate the cooling rates found in MIG/TIG welds. Using this technique, a range of Sc addition levels have been made to two typical Al-aerospace alloys, 2024 and 7475. It has been found that when the Sc level exceeds a critical concentration, small Al 3 Sc primary particles form in the melt and act as very efficient grain nucleants, resulting in simulated fusion zone grain sizes as fine as 15 μm. This exceptional level of grain refinement produced an unusual grain structure that exhibited no dendritic, or cellular, substructure and a large increase in strength and ductility of the castings. Sc also produced changes in the alloy's freezing paths, which cannot yet be fully explained, but led to the appearance of the W phase in the 2024 alloy and, in both alloys, an overall reduction in the amount of eutectic formed during solidification. When coupled with the high level of grain refinement, this behaviour could be used to explain the increased strength and ductility of the castings. In 2000 and 7000 series aluminium alloys, it is therefore, anticipated that optimised Sc bearing filler wires will significantly improve the mechanical properties of the weld metal, as well as reducing the tendency for solidification cracking

  19. Characterization of a structural intermediate of flavivirus membrane fusion.

    Directory of Open Access Journals (Sweden)

    Karin Stiasny

    2007-02-01

    Full Text Available Viral membrane fusion proceeds through a sequence of steps that are driven by triggered conformational changes of viral envelope glycoproteins, so-called fusion proteins. Although high-resolution structural snapshots of viral fusion proteins in their prefusion and postfusion conformations are available, it has been difficult to define intermediate structures of the fusion pathway because of their transient nature. Flaviviruses possess a class II viral fusion protein (E mediating fusion at acidic pH that is converted from a dimer to a trimer with a hairpin-like structure during the fusion process. Here we show for tick-borne encephalitis virus that exposure of virions to alkaline instead of acidic pH traps the particles in an intermediate conformation in which the E dimers dissociate and interact with target membranes via the fusion peptide without proceeding to the merger of the membranes. Further treatment to low pH, however, leads to fusion, suggesting that these monomers correspond to an as-yet-elusive intermediate required to convert the prefusion dimer into the postfusion trimer. Thus, the use of nonphysiological conditions allows a dissection of the flavivirus fusion process and the identification of two separate steps, in which membrane insertion of multiple copies of E monomers precedes the formation of hairpin-like trimers. This sequence of events provides important new insights for understanding the dynamic process of viral membrane fusion.

  20. Evaluation of copper alloys for fusion reactor divertor and first wall components

    DEFF Research Database (Denmark)

    Fabritsiev, S.A.; Zinkle, S.J.; Singh, B.N.

    1996-01-01

    This paper presents a critical analysis of the main factors of radiation damage limiting the possibility to use copper alloys in the ITER divertor and first wall structure. In copper alloys the most significant types of radiation damage in the proposed temperature-dose operation range are swellin...

  1. Determination of atomic cluster structure with cluster fusion algorithm

    DEFF Research Database (Denmark)

    Obolensky, Oleg I.; Solov'yov, Ilia; Solov'yov, Andrey V.

    2005-01-01

    We report an efficient scheme of global optimization, called cluster fusion algorithm, which has proved its reliability and high efficiency in determination of the structure of various atomic clusters.......We report an efficient scheme of global optimization, called cluster fusion algorithm, which has proved its reliability and high efficiency in determination of the structure of various atomic clusters....

  2. Effects of irradiation on ferritic alloys and implications for fusion reactor applications

    International Nuclear Information System (INIS)

    Gelles, D.S.

    1986-07-01

    This paper reviews the ADIP irradiation effects data base on ferritic (martensitic) alloys to provide reactor teams with an understanding of how such alloys will behave for fusion reactor first wall applications. Irradiation affects dimensional stability, strength and toughness. Dimensional stability is altered by precipitation and void swelling. Swelling as high as 25% may occur in some ferritic alloys at 500 dpa. Irradiation alters strength both during and following irradiation. Irradiation at low temperatures leads to hardening whereas at higher temperatures and high exposures, precipitate coarsening can result in softening. Toughness can also be adversely affected by irradiation. Failure can occur in ferritic in a brittle manner and irradiation induced hardening causes brittle failure at higher temperatures. Even at high test temperatures, toughness is reduced due to reduced failure initiation stresses. 39 refs

  3. Structural material properties for fusion application

    Energy Technology Data Exchange (ETDEWEB)

    Tavassoli, A-A. F.

    2008-10-15

    Materials properties requirements for structural applications in the forthcoming and future fusion machines are analyzed with emphasis on safety requirements. It is shown that type 316L(N) used in the main structural components of ITER is code qualified and together with limits imposed on its service conditions and neutron radiation levels, can adequately satisfy ITER vacuum vessel licensing requirements. For the in-vessel components, where nonconventional fabrication methods, such as HIPing, are used, design through materials properties, data is combined with tests on representative mockups to meet the requirements. For divertor parts, where the operating conditions are too severe for components to last throughout the reactor life, replacement of most exposed parts is envisaged. DEMO operating conditions require extension of ITER design criteria to high temperature and high neutron dose rules, as well as to compatibility with cooling and tritium breeding media, depending on the blanket concept retained. The structural material favoured in EU is Eurofer steel, low activation martensitic steel with good ductility and excellent resistance to radiation swelling. However, this material, like other ferritic / martensitic steels, requires post-weld annealing and is sensitive to low temperature irradiation embrittlement. Furthermore, it shows cyclic softening during fatigue, complicating design against fatigue and creep-fatigue. (au)

  4. Generic structural mechanics aspects of fusion magnet systems

    International Nuclear Information System (INIS)

    Reich, M.; Powell, J.R.

    1980-01-01

    Structural mechanic requirements for future large superconducting fusion magnets are assessed. Current structural analysis methods and standards do not yet appear sufficient for a complete evaluation of such systems, under all potential operating and accident conditions. Recommendations are made for development of needed structural methods and specialized standards for fusion magnets. These include, among others, better composite structural methods with various failure criteria for metallic, as well as non-metallic materials, coupled thermal-electrical-structural codes, incorporating winding and fabrication effects, and use of probabilistic methods for life prediction. In order to help meet program goals for fusion commericialization, it is recommended that such work be initiated relatively soon. (orig.)

  5. Shape Memory Alloy-Based Periodic Cellular Structures, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I effort will develop and demonstrate an innovative shape memory alloy (SMA) periodic cellular structural technology. Periodic cellular structures...

  6. Assessment of martensitic steels as structural materials in magnetic fusion devices

    International Nuclear Information System (INIS)

    Rawls, J.M.; Chen, W.Y.K.; Cheng, E.T.; Dalessandro, J.A.; Miller, P.H.; Rosenwasser, S.N.; Thompson, L.D.

    1980-01-01

    This manuscript documents the results of preliminary experiments and analyses to assess the feasibility of incorporating ferromagnetic martensitic steels in fusion reactor designs and to evaluate the possible advantages of this class of material with respect to first wall/blanket lifetime. The general class of alloys under consideration are ferritic steels containing from about 9 to 13 percent Cr with some small additions of various strengthening elements such as Mo. These steels are conventionally used in the normalized and tempered condition for high temperature applications and can compete favorably with austenitic alloys up to about 600 0 C. Although the heat treatment can result in either a tempered martensite or bainite structure, depending on the alloy and thermal treatment parameters, this general class of materials will be referred to as martensitic stainless steels for simplicity

  7. Structural materials requirements for in-vessel components of fusion power plants

    International Nuclear Information System (INIS)

    Schaaf, B. van der

    2000-01-01

    The economic production of fusion energy is determined by principal choices such as using magnetic plasma confinement or generating inertial fusion energy. The first generation power plants will use deuterium and tritium mixtures as fuel, producing large amounts of highly energetic neutrons resulting in radiation damage in materials. In the far future the advanced fuels, 3 He or 11 B, determine power plant designs with less radiation damage than in the first generation. The first generation power plants design must anticipate radiation damage. Solid sacrificing armour or liquid layers could limit component replacements costs to economic levels. There is more than radiation damage resistance to determine the successful application of structural materials. High endurance against cyclic loading is a prominent requirement, both for magnetic and inertial fusion energy power plants. For high efficiency and compactness of the plant, elevated temperature behaviour should be attractive. Safety and environmental requirements demand that materials have low activation potential and little toxic effects under both normal and accident conditions. The long-term contenders for fusion power plant components near the plasma are materials in the range from innovative steels, such as reduced activation ferritic martensitic steels, to highly advanced ceramic composites based on silicon carbide, and chromium alloys. The steels follow an evolutionary path to basic plant efficiencies. The competition on the energy market in the middle of the next century might necessitate the riskier but more rewarding development of SiCSiC composites or chromium alloys

  8. Microstructural Evolution and Creep-Rupture Behavior of A-USC Alloy Fusion Welds

    Science.gov (United States)

    Bechetti, Daniel H.; DuPont, John N.; Siefert, John A.; Shingledecker, John P.

    2016-09-01

    Characterization of the microstructural evolution of fusion welds in alloys slated for use in advanced ultrasupercritical (A-USC) boilers during creep has been performed. Creep-rupture specimens involving INCONEL® 740, NIMONIC® 263 (INCONEL and NIMONIC are registered trademarks of Special Metals Corporation), and Haynes® 282® (Haynes and 282 are registered trademarks of Haynes International) have been analyzed via light optical microscopy, scanning electron microscopy, X-ray diffraction, and thermodynamic and kinetic modeling. Focus has been given to the microstructures that develop along the grain boundaries in these alloys during creep at temperatures relevant to the A-USC process cycle, and particular attention has been paid to any evidence of the formation of local γ'-denuded or γ'-free zones. This work has been performed in an effort to understand the microstructural changes that lead to a weld strength reduction factor (WSRF) in these alloys as compared to solution annealed and aged alloy 740 base metal. γ' precipitate-free zones have been identified in alloy 740 base metal, solution annealed alloy 740 weld metal, and alloy 263 weld metal after creep. Their development during long-term thermal exposure is correlated with the stabilization of phases that are rich in γ'-forming elements ( e.g., η and G) and is suppressed by precipitation of phases that do not contain the γ' formers ( e.g., M23C6 and μ). The location of failure and creep performance in terms of rupture life and WSRF for each welded joint is presented and discussed.

  9. Powder metallurgical processing of self-passivating tungsten alloys for fusion first wall application

    Energy Technology Data Exchange (ETDEWEB)

    López-Ruiz, P.; Ordás, N.; Iturriza, I. [CEIT and Tecnun (University of Navarra), E-20018 San Sebastian (Spain); Walter, M.; Gaganidze, E. [Karlsruhe Institute of Technology (KIT), D-76344 Eggenstein-Leopoldshafen (Germany); Lindig, S.; Koch, F. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, D-85748 Garching (Germany); García-Rosales, C., E-mail: cgrosales@ceit.es [CEIT and Tecnun (University of Navarra), E-20018 San Sebastian (Spain)

    2013-11-15

    Self-passivating tungsten based alloys are expected to provide a major safety advantage compared to pure tungsten, presently the main candidate material for first wall armour of future fusion reactors. In case of a loss of coolant accident with simultaneous air ingress, a protective oxide scale will be formed on the surface of W avoiding the formation of volatile and radioactive WO{sub 3}. Bulk WCr12Ti2.5 alloys were manufactured by mechanical alloying (MA) and hot isostatic pressing (HIP), and their properties compared to bulk WCr10Si10 alloys from previous work. The MA parameters were adjusted to obtain the best balance between lowest possible amount of contaminants and effective alloying of the elemental powders. After HIP, a density >99% is achieved for the WCr12Ti2.5 alloy and a very fine and homogeneous microstructure with grains in the submicron range is obtained. Unlike the WCr10Si10 material, no intergranular ODS phase inhibiting grain growth was detected. The thermal and mechanical properties of the WCr10Si10 material are dominated by the silicide (W,Cr){sub 5}Si{sub 3}; it shows a sharp ductile-to brittle transition in the range 1273–1323 K. The thermal conductivity of the WCr12Ti2.5 alloy is close to 50 W/mK in the temperature range of operation; it exhibits significantly higher strength and lower DBTT – around 1170 K – than the WCr10Si10 material.

  10. Performance limits for fusion first-wall structural materials

    International Nuclear Information System (INIS)

    Smith, D.L.; Majumdar, S.; Billone, M.; Mattas, R.

    2000-01-01

    Key features of fusion energy relate primarily to potential advantages associated with safety and environmental considerations and the near endless supply of fuel. However, high-performance fusion power systems will be required in order to be an economically competitive energy option. As in most energy systems, the operating limits of structural materials pose a primary constraint to the performance of fusion power systems. In the case of fusion power, the first-wall/blanket system will have a dominant impact on both economic and safety/environmental attractiveness. This paper presents an assessment of the influence of key candidate structural material properties on performance limits for fusion first-wall blanket applications. Key issues associated with interactions of the structural materials with the candidate coolant/breeder materials are discussed

  11. Structural characterization of Mumps virus fusion protein core

    International Nuclear Information System (INIS)

    Liu Yueyong; Xu Yanhui; Lou Zhiyong; Zhu Jieqing; Hu Xuebo; Gao, George F.; Qiu Bingsheng; Rao Zihe; Tien, Po

    2006-01-01

    The fusion proteins of enveloped viruses mediating the fusion between the viral and cellular membranes comprise two discontinuous heptad repeat (HR) domains located at the ectodomain of the enveloped glycoproteins. The crystal structure of the fusion protein core of Mumps virus (MuV) was determined at 2.2 A resolution. The complex is a six-helix bundle in which three HR1 peptides form a central highly hydrophobic coiled-coil and three HR2 peptides pack against the hydrophobic grooves on the surface of central coiled-coil in an oblique antiparallel manner. Fusion core of MuV, like those of simian virus 5 and human respiratory syncytium virus, forms typical 3-4-4-4-3 spacing. The similar charecterization in HR1 regions, as well as the existence of O-X-O motif in extended regions of HR2 helix, suggests a basic rule for the formation of the fusion core of viral fusion proteins

  12. Structure of nanocomposites of Al–Fe alloys prepared by ...

    Indian Academy of Sciences (India)

    Wintec

    This difference in the product structure can be attributed to the difference in alloying mechanisms in MA and RSP. Keywords. Nanocomposites; Al–Fe; mechanical alloying; rapid solidification; quasicrystalline. 1. Introduction. Al–Fe alloys are attractive for applications at temperatures beyond those normally associated with ...

  13. Progress in the US program to develop low-activation structural materials for fusion

    International Nuclear Information System (INIS)

    Kurtz, R.J.; Jones, R.H.; Bloom, E.E.; Rowcliffe, A.F.; Smith, D.L.; Odette, G.R.; Wiffen, F.W.

    1999-01-01

    It has long been recognized that attainment of the safety and environmental potential of fusion energy requires the successful development of low-activation materials for the first wall, blanket and other high heat flux structural components. Only a limited number of materials potentially possess the physical, mechanical and low-activation characteristics required for this application. The current US structural materials research effort is focused on three candidate materials: advanced ferritic steels, vanadium alloys, and silicon carbide composites. Recent progress has been made in understanding the response of these materials to neutron irradiation. (author)

  14. Progress in the U.S. program to develop low-activation structural materials for fusion

    International Nuclear Information System (INIS)

    Kurtz, R.J.; Jones, R.H.; Bloom, E.E.; Rowcliffe, A.F.; Smith, D.L.; Odette, G.R.; Wiffen, F.W.

    2001-01-01

    It has long been recognized that attainment of the safety and environmental potential of fusion energy requires the successful development of low-activation materials for the first wall, blanket and other high heat flux structural components. Only a limited number of materials potentially possess the physical, mechanical and low-activation characteristics required for this application. The current U.S. structural materials research effort is focused on three candidate materials: advanced ferritic steels, vanadium alloys, and silicon carbide composites. Recent progress has been made in understanding the response of these materials to neutron irradiation. (author)

  15. Failure analysis of fusion clad alloy system AA3003/AA6xxx sheet under bending

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Y., E-mail: shiyh@mcmaster.ca [Department of Mechanical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L7 (Canada); Jin, H. [Novelis Global Technology Center, P.O. Box 8400, Kingston, Ontario, Canada K7L 5L9 (Canada); Wu, P.D. [Department of Mechanical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L7 (Canada); Lloyd, D.J. [Aluminum Materials Consultants, 106 Nicholsons Point Road, Bath, Ontario, Canada K0H 1G0 (Canada); Embury, D. [Department of Mechanical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L7 (Canada)

    2014-07-29

    An ingot of AA6xxx Al–Si–Mg–Cu alloy clad with AA3003 Al–Mn alloy was co-cast by Fusion technology. Bending tests and numerical modeling were performed to investigate the potential for sub-surface cracking for this laminate system. To simulate particle-induced crack initiation and growth, both random and stringer particles have been selected to mimic the particle distribution in the tested samples. The morphology of cracking in the model was similar to that observed in clad sheet tested in the Cantilever bend test. The crack initiated in the core close to the clad-core interface where the strain in the core is highest, between particles or near particles and propagates along local shear bands in the core, while the clad layer experiences extreme thinning before failure.

  16. Alloys for the fusion reactor environment: a technical assessment

    International Nuclear Information System (INIS)

    1978-01-01

    This technological assessment involves the following: (1) primary and backup materials of choice, (2) testing and manpower requirements, (3) major milestones, (4) natural resources and industrial capability, and (5) conclusions. The first wall/blanket structure was emphasized in the assessment of materials subject to intense radiation

  17. Nuclear data for structural materials of fission and fusion reactors

    International Nuclear Information System (INIS)

    Goulo, V.

    1989-06-01

    The document presents the status of nuclear reaction theory concerning optical model development, level density models and pre-equilibrium and direct processes used in calculation of neutron nuclear data for structural materials of fission and fusion reactors. 6 refs

  18. Medium resolution image fusion, does it enhance forest structure assessment

    CSIR Research Space (South Africa)

    Roberts, JW

    2008-07-01

    Full Text Available This research explored the potential benefits of fusing optical and Synthetic Aperture Radar (SAR) medium resolution satellite-borne sensor data for forest structural assessment. Image fusion was applied as a means of retaining disparate data...

  19. Determination of hydrogen in uranium-niobium-zirconium alloy by inert-gas fusion

    International Nuclear Information System (INIS)

    Carden, W.F.

    1979-12-01

    An improved method has been developed using inert-gas fusion for determining the hydrogen content in uranium-niobium-zirconium (U-7.5Nb-2.5Zr) alloy. The method is applicable to concentrations of hydrogen ranging from 1 to 250 micrograms per gram and may be adjusted for analysis of greater hydrogen concentrations. Hydrogen is determined using a hydrogen determinator. The limit of error for a single determination at the 95%-confidence level (at the 3.7-μg/g-hydrogen level) is +-1.4 micrograms per gram hydrogen

  20. Development of electrically insulating self-healing coatings in vanadium alloys for lithium fusion reactor

    International Nuclear Information System (INIS)

    1999-01-01

    Problems on electrically insulating self-healing coatings (SHC) on vanadium alloys for lithium fusion reactor systems are considered. In particular, the SHC stability and radiation resistance in lithium and effect of magnetic field on the efficiency of the TNR lithium systems are studied. New technological methods for application of self-healing coatings and study on their properties are developed. The vanadium-lithium materials testing in pile loops for solution of the above problems under conditions of the lithium TNR is described [ru

  1. Preliminary design of fusion reactor fuel cleanup system by palladium alloy membrane method

    International Nuclear Information System (INIS)

    Yoshida, Hiroshi; Konishi, Satoshi; Naruse, Yuji

    1981-10-01

    A design of palladium diffuser and Fuel Cleanup System (FCU) for D-T fusion reactor is proposed. Feasibility of palladium alloy membrane method is discussed based on the early studies by the authors. Operating conditions of the palladium diffuser are determined experimentally. Dimensions of the diffuser are estimated from computer simulation. FCU system is designed under the feed conditions of Tritium Systems Test Assembly (TSTA) at Los Alamos Scientific Laboratory. The system is composed of Pd-diffusers, catalytic oxidizer, freezer and zink beds, and has some advantages in system layout and operation. This design can readily be extended to other conditions of plasma exhaust gases. (author)

  2. Keyhole formation and thermal fluid flow-induced porosity during laser fusion welding in titanium alloys: Experimental and modelling

    International Nuclear Information System (INIS)

    Panwisawas, Chinnapat; Perumal, Bama; Ward, R. Mark; Turner, Nathanael; Turner, Richard P.; Brooks, Jeffery W.; Basoalto, Hector C.

    2017-01-01

    High energy-density beam welding, such as electron beam or laser welding, has found a number of industrial applications for clean, high-integrity welds. The deeply penetrating nature of the joints is enabled by the formation of metal vapour which creates a narrow fusion zone known as a “keyhole”. However the formation of the keyhole and the associated keyhole dynamics, when using a moving laser heat source, requires further research as they are not fully understood. Porosity, which is one of a number of process induced phenomena related to the thermal fluid dynamics, can form during beam welding processes. The presence of porosity within a welded structure, inherited from the fusion welding operation, degrades the mechanical properties of components during service such as fatigue life. In this study, a physics-based model for keyhole welding including heat transfer, fluid flow and interfacial interactions has been used to simulate keyhole and porosity formation during laser welding of Ti-6Al-4V titanium alloy. The modelling suggests that keyhole formation and the time taken to achieve keyhole penetration can be predicted, and it is important to consider the thermal fluid flow at the melting front as this dictates the evolution of the fusion zone. Processing induced porosity is significant when the fusion zone is only partially penetrating through the thickness of the material. The modelling results are compared with high speed camera imaging and measurements of porosity from welded samples using X-ray computed tomography, radiography and optical micrographs. These are used to provide a better understanding of the relationship between process parameters, component microstructure and weld integrity.

  3. Alloy development for fast induced radioactivity decay for fusion reactor applications

    International Nuclear Information System (INIS)

    Klueh, R.L.; Bloom, E.E.

    1984-01-01

    During the operation of a fusion reactor, the structural material of the first wall and blanket structure will become highly radioactive from activation by the high-energy fusion neutrons. A difficult radioactive waste management problem will be involved in the disposal of this material after the service lifetime is complete. One way to minimize the management problem is the use of structural materials where the radioactive isotopes in the irradiated material decay to levels that allow for simplified disposal techniques. We are exploring how ferritic and austenitic steels could be developed to meet this objective

  4. SCC propagation and cessation behavior near the fusion boundary of dissimilar weld joint with Ni-based weld metal and low alloy steel

    International Nuclear Information System (INIS)

    Ishizawa, Makoto; Abe, Hiroshi; Watanabe, Yutaka

    2009-01-01

    The purpose of this study is to investigate the following items focused on the microstructure near the fusion boundary of dissimilar weld joint with Ni-based weld metal and low alloy steel; (1) Microstructural characteristics near the fusion boundary, (2) Dominant factor that makes crack retardation near the fusion boundary. Main conclusions can be summarized as follows; (1) From the results of CBB tests, it has been understood that the low alloy steel has no SCC susceptibility and that there is a difference in oxidation behavior between high and low sulfur containing low alloy steel, (2) In Alloy182/LAS sample, most of crack tips were located at the fusion boundary. It has been thought that crack become less active when crack reach at fusion boundary, (3) It has been suggested that the dominant factor of crack retardation is low SCC susceptibility of low alloy steel in high temperature water. (author)

  5. STRUCTURE FORMATION OF ALLOYS ON IRON BASIS AFTER LASER ALLOYING

    Directory of Open Access Journals (Sweden)

    О. V. Diachenko

    2016-01-01

    Full Text Available The paper is devoted to investigations on influence of laser treatment regimes of gas-thermal and adhesive coatings from self-fluxing powders on iron basis and after melting with modifying plaster on their roughness and phase composition. One of mathematical planning methods that is a complete factor experiment method has been used for investigation of parameters’ influence on micro-geometry of coatings. The executed investigations have made it possible to observe a general regularity which does not depend on a type of alloying plaster: while increasing speed of laser beam relatively to treated part, beam diameter value of Ra parameter is becoming less. Decrease in height of surface irregularities in case of increasing laser beam speed is related with intensification of evaporation processes. An increase in beam diameter diminishes Ra parameter of the surface. This is due to the fact that decrease in power density occurs at high rate of beam defocusing. Overlapping coefficient does not exert a pronounced effect on Ra parameter of fused coatings. While increasing the speed of laser beam relatively to the part structure is transferred from dendrite into supersaturated one with carbide and boride precipitations. It has been established that technological parameters of laser treatment and particularly speed of laser beam influence on coating composition. While increasing the speed up to v5 = 5 × 10–3 m/s amount of chromium has become larger by 1.5-fold that resulted in increase of micro-hardness of the coating from 9.5–10.1 GPa up to 11.04–15.50 GPa.

  6. Radiation damage simulation studies in the Harwell VEC of selected austenitic and ferritic alloys for fusion applications

    Energy Technology Data Exchange (ETDEWEB)

    Mazey, D J; Walters, G P; Buckley, S N; Hanks, W; Bolster, D E.J.; Murphy, S M

    1988-07-01

    Three austenitic (316 L, 316-Ti, 316-Nb); four high-nickel (IN 625, IN 706, PE 16, Fe-25Ni-8Cr) and four ferritic (CRM 12, FV 448, FV 607, FI) alloys have been irradiated with 46 MeV Ni or 20 MeV Cr ions in the Harwell VEC to simulated fusion-reactor doses up to 110 dpa (proportional to 10 MW-yr m/sup -2/) at temperatures from 425 to 625/sup 0/C. Gas production rates appropriate to fusion were obtained from a mixed beam of He+H/sub 2/ in the ratio 1:4 He:H with gas/dpa ratios of 13 appm He/dpa and 52 appm H/dpa. The 316 alloys showed irradiation-induced precipitation and swelling as high as 40% in ST 316-Ti after 110 dpa at 625/sup 0/C. Low swelling (e.g. <2% at 110 dpa) was observed in the high-nickel alloys. The ferritic/martensitic alloys showed negligible swelling (e.g. <0.2% in FV 607 after 100 dpa at 475/sup 0/C). The results demonstrate the high swelling behaviour of 316 alloys and the better swelling resistance of high-nickel and ferritic alloys under simulated fusion conditions.

  7. The problem of helium in structural materials for fusion reactor

    International Nuclear Information System (INIS)

    Nikiforov, A.S.; Zakharov, A.P.; Chuev, V.I.

    1982-01-01

    The processes of helium buildup in some metals and alloys at different energy neutron flux irradiation under thermonuclear reactor conditions are considered. The data on high temperature helium embrittlement of a number of stainless steels, titanium and aluminium alloys etc. are given A review of experiments concerning the implanted helium behaviour is presented. Possible reactions between helium atoms and point defects or their clusters are discussed. Analysed are material structure variations upon buildup in them up to 1 at % of helium

  8. Radiation Tolerance of Controlled Fusion Welds in High Temperature Oxidation Resistant FeCrAl Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gussev, Maxim N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-08-01

    High temperature oxidation resistant iron-chromium-aluminum (FeCrAl) alloys are candidate alloys for nuclear applications due to their exceptional performance during off-normal conditions such as a loss-of-coolant accident (LOCA) compared to currently deployed zirconium-based claddings [1]. A series of studies have been completed to determine the weldability of the FeCrAl alloy class and investigate the weldment performance in the as-received (non-irradiated) state [2,3]. These initial studies have shown the general effects of composition and microstructure on the weldability of FeCrAl alloys. Given this, limited details on the radiation tolerance of FeCrAl alloys and their weldments exist. Here, the highest priority candidate FeCrAl alloys and their weldments have been investigated after irradiation to enable a better understanding of FeCrAl alloy weldment performance within a high-intensity neutron field. The alloys examined include C35M (Fe-13%Cr-5% Al) and variants with aluminum (+2%) or titanium carbide (+1%) additions. Two different sub-sized tensile geometries, SS-J type and SS-2E (or SS-mini), were neutron irradiated in the High Flux Isotope Reactor to 1.8-1.9 displacements per atom (dpa) in the temperature range of 195°C to 559°C. Post irradiation examination of the candidate alloys was completed and included uniaxial tensile tests coupled with digital image correlation (DIC), scanning electron microscopy-electron back scattered diffraction analysis (SEM-EBSD), and SEM-based fractography. In addition to weldment testing, non-welded parent material was examined as a direct comparison between welded and non-welded specimen performance. Both welded and non-welded specimens showed a high degree of radiation-induced hardening near irradiation temperatures of 200°C, moderate radiation-induced hardening near temperatures of 360°C, and almost no radiation-induced hardening at elevated temperatures near 550°C. Additionally, low-temperature irradiations showed

  9. Compatibility of vanadium alloys with reactor-grade helium for fusion reactor applications

    International Nuclear Information System (INIS)

    Bell, G.E.C.; Bishop, P.S.

    1993-01-01

    Tests were conducted to determine the compatibility of vanadium alloys with reactor-grade helium and to define the helium gas chemistry requirements for fusion reactors, miniature tensile specimens of V-5Cr-5Ti. V-10Cr-5Ti, and V-12.5Cr-5 Ti were exposed in a once-through system to helium with 70 vppm-H 2 (measured oxygen partial pressures of 10 -12 atm) and bottle helium (measured oxygen partial pressures of -4 atm) between 500 and 700 degree C for up to 1008 h. The weight changes in the specimens were recorded. The helium-exposed specimens were tensile tested, and the effects of exposure on mechanical properties were assessed. Exposure between 500 and 700 degree C for 1008 h in He+70 vppm-H 2 resulted in complete embrittlement of all the alloys in room temperature tensile tests. The fracture mode was primarily cleavage, probably caused by a hydrogen-induced shift in the ductile to brittle transition temperature (DBTT). Weight gains increased with temperature and were largest for the V-5Cr-5Ti alloy. Specimens exposed for 531 h between 500 and 700 degree C in bottle He exhibited two distinct fracture morphologies on the fracture surfaces. Brittle cleavage around the edges of specimens gave way to ductile dimpling in the center of the specimens. The brittle region around the periphery of the specimen is most likely the highest vanadium oxide. V 2 O 5

  10. FeCrAl and Zr alloys joined using hot isostatic pressing for fusion energy applications

    International Nuclear Information System (INIS)

    Park, Dong Jun; Kim, Hyun Gil; Park, Jeong Yong; Jung, Yang Il; Park, Jung Hwan; Koo, Yang Hyun

    2016-01-01

    Highlights: • FeCrAl and Zr alloys were successfully joined by hot isostatic pressing (HIP). • The thickness of diffusion layer increased with an increase in HIP temperature. • Significant inter-diffusion was observed for HIP at 1150 °C. • Maximum joint strength was achieved at HIP temperature of 700 °C. - Abstract: FeCrAl and Zr alloys were joined by a hot isostatic pressing (HIP) method for fusion energy applications. The optimum conditions for the joining process were studied. The HIP temperatures were varied from 700 to 1050 °C. The mechanical properties of the HIPed samples were evaluated by four-point bending and tensile tests. The FeCrAl and Zr alloys HIPed at 700 °C showed higher joint strength than the other samples. The joint strength decreased with an increase in the HIP temperature from 700 to 950 °C and significantly dropped at 1050 °C. Transmission electron microscopy, scanning electron microscopy, and optical microscopy were used to characterize the joints and interface region of the HIPed samples. The joints appeared to be tightly bonded and no intermetallic compounds or gaps were observed at the interface for HIP temperatures up to 950 °C. A diffusion layer formed at the interface and its thickness increased with the HIP temperature. HIP at 1050 °C, on the other hand, resulted in significant inter-diffusion and formation of brittle inter-metallic compounds at the interface.

  11. Proceedings of the 2. workshop on vanadium alloy development for fusion

    International Nuclear Information System (INIS)

    Osch, E.V. van

    1996-10-01

    From 20 to 22 May 1996 the Second IEA Vanadium Alloy Development for Fusion Workshop was held at the Netherlands Energy Research Foundation, ECN in Petten. Twenty three experts from the European Union, Japan, the Russian Federation and the United States exchanged results and analyses of completed experiments and discussed the program planning. The manufacturing of half-finished products and the optimization of subsequent heat treatments were presented and discussed in the first session. The problems and solutions to joining vanadium alloy half-finished products by welding and brazing have been addressed in another session. Corrosion and compatibility properties have been evaluated in a different session together with coating requirements. Several sessions were devoted to the effects of radiation on the mechanical properties, especially toughness, of vanadium alloys. Also the role of the transmutation product helium, in particular its introduction into specimens, was evaluated. The respective plans of the four parties for continuation of the ongoing research and development programs have been discussed with the emphasis on avoiding duplications in the area of radiation experiments. The critical issues were identified and the related priorities discussed in the time frame set by the schedule for the building of ITER test modules and with the long term DEMO requirements in mind. (orig.)

  12. Proceedings of the 2. workshop on vanadium alloy development for fusion

    Energy Technology Data Exchange (ETDEWEB)

    Osch, E.V. van [ed.

    1996-10-01

    From 20 to 22 May 1996 the Second IEA Vanadium Alloy Development for Fusion Workshop was held at the Netherlands Energy Research Foundation, ECN in Petten. Twenty three experts from the European Union, Japan, the Russian Federation and the United States exchanged results and analyses of completed experiments and discussed the program planning. The manufacturing of half-finished products and the optimization of subsequent heat treatments were presented and discussed in the first session. The problems and solutions to joining vanadium alloy half-finished products by welding and brazing have been addressed in another session. Corrosion and compatibility properties have been evaluated in a different session together with coating requirements. Several sessions were devoted to the effects of radiation on the mechanical properties, especially toughness, of vanadium alloys. Also the role of the transmutation product helium, in particular its introduction into specimens, was evaluated. The respective plans of the four parties for continuation of the ongoing research and development programs have been discussed with the emphasis on avoiding duplications in the area of radiation experiments. The critical issues were identified and the related priorities discussed in the time frame set by the schedule for the building of ITER test modules and with the long term DEMO requirements in mind. (orig.).

  13. Fusion zone microstructure of laser beam welded directionally solidified Ni3Al-base alloy IC6

    International Nuclear Information System (INIS)

    Ding, R.G.; Ojo, O.A.; Chaturvedi, M.C.

    2006-01-01

    The fusion zone microstructure of laser welded alloy IC6 was examined. Extensive weld-metal cracking was observed to be closely associated with non-equilibrium eutectic-type microconstituents identified as consisting of γ, γ' and NiMo (Y) phases. Their formation has been related to modification of primary solidification path due to reduced solutal microsegregation

  14. A hierarchical structure approach to MultiSensor Information Fusion

    Energy Technology Data Exchange (ETDEWEB)

    Maren, A.J. (Tennessee Univ., Tullahoma, TN (United States). Space Inst.); Pap, R.M.; Harston, C.T. (Accurate Automation Corp., Chattanooga, TN (United States))

    1989-01-01

    A major problem with image-based MultiSensor Information Fusion (MSIF) is establishing the level of processing at which information should be fused. Current methodologies, whether based on fusion at the pixel, segment/feature, or symbolic levels, are each inadequate for robust MSIF. Pixel-level fusion has problems with coregistration of the images or data. Attempts to fuse information using the features of segmented images or data relies an a presumed similarity between the segmentation characteristics of each image or data stream. Symbolic-level fusion requires too much advance processing to be useful, as we have seen in automatic target recognition tasks. Image-based MSIF systems need to operate in real-time, must perform fusion using a variety of sensor types, and should be effective across a wide range of operating conditions or deployment environments. We address this problem through developing a new representation level which facilitates matching and information fusion. The Hierarchical Scene Structure (HSS) representation, created using a multilayer, cooperative/competitive neural network, meets this need. The MSS is intermediate between a pixel-based representation and a scene interpretation representation, and represents the perceptual organization of an image. Fused HSSs will incorporate information from multiple sensors. Their knowledge-rich structure aids top-down scene interpretation via both model matching and knowledge-based,region interpretation.

  15. A hierarchical structure approach to MultiSensor Information Fusion

    Energy Technology Data Exchange (ETDEWEB)

    Maren, A.J. [Tennessee Univ., Tullahoma, TN (United States). Space Inst.; Pap, R.M.; Harston, C.T. [Accurate Automation Corp., Chattanooga, TN (United States)

    1989-12-31

    A major problem with image-based MultiSensor Information Fusion (MSIF) is establishing the level of processing at which information should be fused. Current methodologies, whether based on fusion at the pixel, segment/feature, or symbolic levels, are each inadequate for robust MSIF. Pixel-level fusion has problems with coregistration of the images or data. Attempts to fuse information using the features of segmented images or data relies an a presumed similarity between the segmentation characteristics of each image or data stream. Symbolic-level fusion requires too much advance processing to be useful, as we have seen in automatic target recognition tasks. Image-based MSIF systems need to operate in real-time, must perform fusion using a variety of sensor types, and should be effective across a wide range of operating conditions or deployment environments. We address this problem through developing a new representation level which facilitates matching and information fusion. The Hierarchical Scene Structure (HSS) representation, created using a multilayer, cooperative/competitive neural network, meets this need. The MSS is intermediate between a pixel-based representation and a scene interpretation representation, and represents the perceptual organization of an image. Fused HSSs will incorporate information from multiple sensors. Their knowledge-rich structure aids top-down scene interpretation via both model matching and knowledge-based,region interpretation.

  16. NASA-UVa light aerospace alloy and structures technology program

    Science.gov (United States)

    Gangloff, Richard P.; Haviland, John K.; Herakovich, Carl T.; Pilkey, Walter D.; Pindera, Marek-Jerzy; Scully, John R.; Stoner, Glenn E.; Swanson, Robert E.; Thornton, Earl A.; Wawner, Franklin E., Jr.

    1991-01-01

    The general objective of the NASA-UVa Light Aerospace Alloy and Structures Technology Program was to conduct research on the performance of next generation, light weight aerospace alloys, composites, and associated thermal gradient structures. The following research areas were actively investigated: (1) mechanical and environmental degradation mechanisms in advanced light metals and composites; (2) aerospace materials science; (3) mechanics of materials and composites for aerospace structures; and (4) thermal gradient structures.

  17. Structure of Mn40Zn60 liquid alloy

    International Nuclear Information System (INIS)

    Sbihi, D Es; Grosdidier, B; Gasser, J G

    2008-01-01

    In this work we present the structural study of the Mn 40 Zn 60 liquid alloy, whose two components have a high vapour pressure. The structure has been measured by neutron diffraction. The investigation of the chemical order in this alloy was readily made possible. This is due to the manganese negative scattering length which allows a good contrast. A magnetic correction has been considered since manganese is paramagnetic in the liquid state. An 'effective' spin is obtained and its value is discussed. The interpretation of the atomic structure is done in the frame of the Bhatia-Thornton formalism, (S NN (q), S NC (q), S CC (q)) which allows to separate topological, size and chemical effects. It appears clearly that manganese ions and zinc ions have approximately the same radius in the alloy as S NC (q) ≅ 0. The Bhatia-Thornton number-number partial structure factor S NN (q) has been approximated by a linear combination of the experimental structure factors of the two alloy pure components. In the frame of this assumption, the Bhatia-Thornton concentration-concentration partial structure factor S CC (q) is obtained, and shows clearly that this alloy is hetero-coordinated. The hard sphere model cannot explain the structure of this alloy. Its behaviour is compared to other manganese-polyvalent alloys and the general trends are discussed

  18. 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.)

  19. Austenitic stainless steels and high strength copper alloys for fusion components

    International Nuclear Information System (INIS)

    Rowcliffe, A.F.; Zinkle, S.J.; Alexander, D.J.; Stubbins, J.F.

    1998-01-01

    An austenitic stainless steel (316LN), an oxide-dispersion-strengthened copper alloy (GlidCop A125), and a precipitation-hardened copper alloy (Cu-Cr-Zr) are the primary structural materials for the ITER first wall/blanket and divertor systems. While there is a long experience of operating 316LN stainless steel in nuclear environments, there is no prior experience with the copper alloys in neutron environments. The ITER first wall (FW) consists of a stainless steel shield with a copper alloy heat sink bonded by hot isostatic pressing (HIP). The introduction of bi-layer structural material represents a new materials engineering challenge; the behavior of the bi-layer is determined by the properties of the individual components and by the nature of the bond interface. The development of the radiation damage microstructure in both classes of materials is summarized and the effects of radiation on deformation and fracture behavior are considered. The initial data on the mechanical testing of bi-layers indicate that the effectiveness of GlidCop A125 as a FW heat sink material is compromised by its strongly anisotropic fracture toughness and poor resistance to crack growth in a direction parallel to the bi-layer interface. (orig.)

  20. Design study of blanket structure for tokamak experimental fusion reactor

    International Nuclear Information System (INIS)

    1979-11-01

    Design study of the blanket structure for JAERI Experimental Fusion Reactor (JXFR) has been carried out. Studied here were fabrication and testing of the blanket structure (blanket cells, blanket rings, piping and blanket modules), assembly and disassembly of the blanket module, and monitering and testing technique. Problems in design and fabrication of the blanket structure could be revealed. Research and development problems for the future were also disclosed. (author)

  1. A comparison of implantation-driven permeation characteristics of fusion reactor structural materials

    Science.gov (United States)

    Longhurst, G. R.; Anderl, R. A.; Struttmann, D. A.

    1986-11-01

    Implantation-driven permeation experiments have been conducted on samples of the ferritic steel HT-9, the austenitic Primary Candidate Alloy (PCA) and the vanadium alloy V-15Cr-5Ti using D 3+ ions under conditions that simulate charge-exchange neutral loading on a fusion reactor first wall. The steels all exhibited an initially intense permeation "spike" followed by an exponential decrease to low steady-state values. That spike was not evident in the V-15Cr-5Ti experiments. Steady-state permeation was highest in the vanadium alloy and lowest in the austenitic steel. Though permeation rates in the HT-9 were lower than those in V-15Cr-5Ti, permeation transients were much faster in HT-9 than in other materials tested. Sputtering of the steel surface resulted in enhanced reemission, whereas in the vanadium tests, recombination and diffusivity both appeared to diminish as the deuterium concentration rose. We conclude that for conditions comparable to those of these experiments, tritium retention and permeation loss in first wall structures made of steels will be less than in structures made of V-15Cr-5Ti.

  2. Comparison on implantation-driven permeation characteristics of fusion reactor structural materials

    Energy Technology Data Exchange (ETDEWEB)

    Longhurst, G.R.; Anderl, R.A.; Struttmann, D.A. (Idaho National Engineering Lab., Idaho Falls)

    Implantation-driven permeation experiments have been conducted on samples of the ferritic steel HT-9, the austenitic Primary Candidate Alloy (PCA) and the vanadium alloy V-15Cr-5Ti using D{sub 3}{sup +} ions under conditions that simulate charge-exchange neutral loading on a fusion reactor first wall. The steels all exhibited an initially intense permeation spike followed by an exponential decrease to low steady-state values. That spike was not evident in the V-15Cr-5Ti experiments. Steady-state permeation was highest in the vanadium alloy and lowest in the austenitic steel. Though permeation rates in the HT-9 were lower than those in V-15Cr-5Ti, permeation transients were much faster in HT-9 than in other materials tested. Sputtering of the steel surface resulted in enhanced reemission, whereas in the vanadium tests, recombination and diffusivity both appeared to diminish as the deuterium concentration rose. We conclude that for conditions comparable to those of these experiments, tritium retention and permeation loss in first wall structures made of steels will be less than in structures made of V-15Cr-5Ti.

  3. Comparison of implantation-driven permeation characteristics of fusion reactor structural materials

    International Nuclear Information System (INIS)

    Longhurst, G.R.; Anderl, R.A.; Struttmann, D.A.

    1986-01-01

    Implantation-driven permeation experiments have been conducted on samples of the ferritic steel HT-9, the austenitic Primary Candidate Alloy (PCA) and the vanadium alloy V-15Cr-5Ti using D 3 + ions under conditions that simulate charge-exchange neutral loading on a fusion reactor first wall. The steels all exhibited an initially intense permeation ''spike'' followed by an exponential decrease to low steady-state values. That spike was not evident in the V-15Cr-5Ti experiments. Steady-state permeation was highest in the vanadium alloy and lowest in the austenitic steel. Though permeation rates in the HT-9 were lower than those in V-15Cr-5Ti, permeation transients were much faster in HT-9 than in other materials tested. Ion-beam sputtering of the surface in the steel experiments resulted in enhanced remission at the front surface, whereas in the vanadium tests, recombination and diffusivity both appeared to diminish as the deuterium concentration rose. This may be due to a phase change in the material. We conclude that for conditions comparable to those of these experiments, tritium retention and loss in first wall structures made of steels will be less than in structures made of V-15Cr-5Ti

  4. Reduced activation structural materials for fusion power plants - The European Union program

    International Nuclear Information System (INIS)

    Schaaf, B. van der; Le Marois, G.; Moeslang, A.; Victoria, M.

    2003-01-01

    The competition of fusion power plants with the renewable energy sources in the second half of the 21st century requires structural materials operating at high temperatures, and sufficient radiation resistance to ensure high plant efficiency and availability. The reduced activation materials development in the EU counts several steps regarding the radiation damage resistance: 75 dpa for DEMO and 150 dpa and beyond for power plants. The maximum operating temperature development line ranges from the present day from the present day feasible 600 K up to 1300- K in advanced power plants. The reduced activation steel, RAS, forms the reference for the development efforts. EUROFER has been manufactured in the EU on industrial scale with specified purity and mechanical properties up to 825 K. The oxide dispersion strengthened , ODS, variety of RAS should reach the 925 K operation limit. The EU has selected silicon carbide ceramic composite as the primary high temperature, 1300 K, goal. On a small scale the potential of tungsten alloys for higher temperatures is investigated. The present test environments for radiation resistance are insufficient to provide data for DEMO. Hence the support of the EU for the International Fusion Materials Irradiation facility. The computational modelling is expected to guide the materials development and the design of near plasma components. The EU co-operates closely with Japan, the RF and US in IEA and IAEA co-ordinated agreements, which are highly beneficial for the fusion structural materials development. (author)

  5. Creation of Novel Solid-Solution Alloy Nanoparticles on the Basis of Density-of-States Engineering by Interelement Fusion.

    Science.gov (United States)

    Kobayashi, Hirokazu; Kusada, Kohei; Kitagawa, Hiroshi

    2015-06-16

    Currently 118 known elements are represented in the periodic table. Of these 118 elements, only about 80 elements are stable, nonradioactive, and widely available for our society. From the viewpoint of the "elements strategy", we need to make full use of the 80 elements to bring out their latent ability and create innovative materials. Furthermore, there is a strong demand that the use of rare or toxic elements be reduced or replaced while their important properties are retained. Advanced science and technology could create higher-performance materials even while replacing or reducing minor or harmful elements through the combination of more abundant elements. The properties of elements are correlated directly with their electronic states. In a solid, the magnitude of the density of states (DOS) at the Fermi level affects the physical and chemical properties. In the present age, more attention has been paid to improving the properties of materials by means of alloying elements. In particular, the solid-solution-type alloy is advantageous because the properties can be continuously controlled by tuning the compositions and/or combinations of the constituent elements. However, the majority of bulk alloys are of the phase-separated type under ambient conditions, where constituent elements are immiscible with each other. To overcome the challenge of the bulk-phase metallurgical aspects, we have focused on the nanosize effect and developed methods involving "nonequilibrium synthesis" or "a process of hydrogen absorption/desorption". We propose a new concept of "density-of-states engineering" for the design of materials having the most desirable and suitable properties by means of "interelement fusion". In this Account, we describe novel solid-solution alloys of Pd-Pt, Ag-Rh, and Pd-Ru systems in which the constituent elements are immiscible in the bulk state. The homogeneous solid-solution alloys of Pd and Pt were created from Pd core/Pt shell nanoparticles using a

  6. Electronic structure theory of alloy phase stability

    International Nuclear Information System (INIS)

    Turchi, P.E.A.; Sluiter, M.

    1992-01-01

    We present a brief overview of the advanced methodology which has been developed and applied to the study of phase stability properties in substitutional alloys. The approach is based on the real space version of the Generalized Perturbation Method within the Korringa-Kohn-Rostoker multiple scattering formulation of the Coherent Potential Approximation. Temperature effects are taken into account with a generalized meanfield approach, namely the Cluster Variation Method, or with Monte-Carlo simulations. We show that this approach is well suited for studying ground state properties of substitutional alloys, for calculating energies of idealized interfaces and antiphase boundaries, and finally to compute alloy phase diagrams

  7. Shape Memory Alloy-Based Periodic Cellular Structures, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase II effort will continue to develop and demonstrate an innovative shape memory alloy (SMA) periodic cellular structural technology. Periodic cellular...

  8. Structure of hardened alloys of Sr-Rh system

    International Nuclear Information System (INIS)

    Dobromyslov, A.V.; Taluth, N.I.

    1997-01-01

    Methods of X-ray diffraction analysis, optical metallography, transmission electron microscopy and hardness measurement were applied to study the structure of hardened zirconium-rhodium system alloys with rhodium contents up to 4.5 at.%. It is shown that in hardening alloys with rhodium concentration lower 2.2 at.% the eutectoid decomposition takes place and bainite-like structure is formed. A metastable ω-phase is formed in alloys with rhodium concentration equal to 2.65 at.% and above. The formation of ω-phase suppresses the process of eutectoid decomposition

  9. Structure and grindability of dental Ti-Cr alloys

    International Nuclear Information System (INIS)

    Hsu, H.-C.; Wu, S.-C.; Chiang, T.-Y.; Ho, W.-F.

    2009-01-01

    The purpose of this study was to investigate the structure and microhardness of a series of binary Ti-Cr alloys with Cr contents up to 30 wt%. In addition, the grindability was also evaluated using an electric dental handpiece with SiC wheels, with the goal of developing a titanium alloy with better mechanical properties and machinability than commercially pure titanium (c.p. Ti), a metal generally considered to be difficult to machine. This study evaluated the phase and structure of Ti-Cr alloys, using an X-ray diffraction (XRD) for phase analysis and optical microscope for microstructure of the etched alloys. Grindability was evaluated by measuring the amount of metal volume removed after grinding for 1 min. Results indicated that the structure of Ti-Cr alloys is sensitive to the Cr content. The cast c.p. Ti has a hexagonal α phase. With 5 wt% Cr, metastable β phase starts to be retained. With Cr contents higher than 10 wt%, the equi-axed β phase is almost entirely retained. In addition, athermal ω phase was found in the Ti-5Cr and Ti-10Cr alloys. The largest quantity of ω phase and highest microhardness were found in Ti-10Cr alloy. The grinding rate of the Ti-Cr alloys showed a similar tendency to the microhardness. The Ti-10Cr alloy exhibited the best grindability, especially at 1000 m/min, which presumably due to the brittle nature of the alloy containing the ω phase in the β matrix.

  10. Structure formation of 5083 alloy during friction stir welding

    Science.gov (United States)

    Zaikina, A. A.; Kolubaev, A. V.; Sizova, O. V.; Ivanov, K. V.; Filippov, A. V.; Kolubaev, E. A.

    2017-12-01

    This paper provides a comparative study of structures obtained by friction stir welding and sliding friction of 5083 Al alloy. Optical and electron microscopy reveals identical fine-grained structures with a grain size of ˜5 µm both in the weld nugget zone and subsurface layer in friction independently of the initial grain size of the alloy. It has been suggested that the grain boundary sliding is responsible for the specific material flow pattern in both techniques considered.

  11. Shape Memory Alloy Adaptive Structures, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I effort will demonstrate and scale up an innovative manufacturing process that yields aerospace grade shape memory alloy (SMA) solids and periodic...

  12. Impurity concentration limits and activation in fusion reactor structural materials

    International Nuclear Information System (INIS)

    Zucchetti, M.

    1991-01-01

    This paper examines waste management problems related to impurity activation in first-wall, shield, and magnet materials for fusion reactors. Definitions of low activity based on hands-on recycling, remote recycling, and shallow land burial waste management criteria are discussed. Estimates of the impurity concentration in low-activation materials (elementally substituted stainless steels and vanadium alloys) are reported. Impurity activation in first-wall materials turns out to be critical after a comparison of impurity concentration limits and estimated levels. Activation of magnet materials is then considered: Long-term activity is not a concern, while short-term activity is. In both cases, impurity activation is negligible. Magnet materials, and all other less flux-exposed materials, have no practical limitation on impurities in terms of induced radioactivity

  13. Low activation ferritic alloys

    Science.gov (United States)

    Gelles, David S.; Ghoniem, Nasr M.; Powell, Roger W.

    1986-01-01

    Low activation ferritic alloys, specifically bainitic and martensitic stainless steels, are described for use in the production of structural components for nuclear fusion reactors. They are designed specifically to achieve low activation characteristics suitable for efficient waste disposal. The alloys essentially exclude molybdenum, nickel, nitrogen and niobium. Strength is achieved by substituting vanadium, tungsten, and/or tantalum in place of the usual molybdenum content in such alloys.

  14. Mechanical properties along interfaces of bonded structures in fusion reactors

    International Nuclear Information System (INIS)

    Hassan, M.H.; Kulcinski, G.L.

    1993-01-01

    Proper assessment of the mechanical properties along interfaces of bonded structures currently used in many fusion reactor designs is essential to compare the different fabrication techniques. A Mechanical Properties Microprobe (MPM) was used to measure hardness and Young's modules along the interfaces of Be/Cu bonded structure. The MPM was able to distinguish different fabrication techniques by a direct measurement of the hardness, Young's modules, and H/E 2 which reflects the ability of deformation of the interfacial region

  15. FINEMET type alloy without Si: Structural and magnetic properties

    International Nuclear Information System (INIS)

    Muraca, D.; Cremaschi, V.; Moya, J.; Sirkin, H.

    2008-01-01

    Magnetic and structural properties of a Finemet type alloy (Fe 73.5 Ge 15.5 Nb 3 B 7 Cu 1 ) without Si and high Ge content were studied. Amorphous material was obtained by the melt spinning technique and was heat treated at different temperatures for 1 h under high vacuum to induce the nanocrystallization of the sample. The softest magnetic properties were obtained between 673 and 873 K. The role of Ge on the ferromagnetic paramagnetic transition of the as-quenched alloys and its influence on the crystallization process were studied using a calorimetric technique. Moessbauer spectroscopy was employed in the nanocrystallized alloy annealed at 823 K to obtain the composition of the nanocrystals and the amorphous phase fraction. Using this data and magnetic measurements of the as-quenched alloy, the magnetic contribution of nanocrystals to the alloy annealed at 823 K was estimated via a linear model

  16. Fusion

    CERN Document Server

    Mahaffey, James A

    2012-01-01

    As energy problems of the world grow, work toward fusion power continues at a greater pace than ever before. The topic of fusion is one that is often met with the most recognition and interest in the nuclear power arena. Written in clear and jargon-free prose, Fusion explores the big bang of creation to the blackout death of worn-out stars. A brief history of fusion research, beginning with the first tentative theories in the early 20th century, is also discussed, as well as the race for fusion power. This brand-new, full-color resource examines the various programs currently being funded or p

  17. Structure of eutectic alloys of Au with Si and Ge

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, S. [Faculty of Sciences, Kyushu University, 4-2-1, Ropponmatsu, Fukuoka 810-8560 (Japan)], E-mail: takeda@rc.kyushu-u.ac.jp; Fujii, H. [Graduate School of Sciences, Kyushu University, 4-2-1, Ropponmatsu, Fukuoka 810-8560 (Japan); Kawakita, Y. [Faculty of Sciences, Kyushu University, 4-2-1, Ropponmatsu, Fukuoka 810-8560 (Japan); Tahara, S.; Nakashima, S. [Graduate School of Sciences, Kyushu University, 4-2-1, Ropponmatsu, Fukuoka 810-8560 (Japan); Kohara, S.; Itou, M. [Japan Synchrotron Radiation Research Institute, 1-1-1 Koto Sayo-cho, Sayo Hyogo 679-5198 (Japan)

    2008-03-06

    Au-Si and Au-Ge alloy systems have a deep eutectic point in the Au-rich concentration region where the melting point falls down to 633 K. In order to investigate the liquid structure in relation to the glass-forming tendency of these alloys, high-energy X-ray diffraction measurements have been carried out at the eutectic composition and at compositions with excess amounts of Au or IVb element. The nearest neighbor correlations in the eutectic liquids are intense and sharp in the pair distribution function and exhibit a rather small temperature dependence in comparison with those alloys of other than the eutectic composition. Structural models for these liquid alloys are proposed with the aid of reverse Monte Carlo simulation. The reproduced atomic arrangements around the eutectic region exhibit a substitutional-type structure where the dense random packing of Au atoms is preserved and Si or Ge atoms occupy the Au-sites at random.

  18. Discovering Music Structure via Similarity Fusion

    DEFF Research Database (Denmark)

    for representing music structure is studied in a simplified scenario consisting of 4412 songs and two similarity measures among them. The results suggest that the PLSA model is a useful framework to combine different sources of information, and provides a reasonable space for song representation.......Automatic methods for music navigation and music recommendation exploit the structure in the music to carry out a meaningful exploration of the “song space”. To get a satisfactory performance from such systems, one should incorporate as much information about songs similarity as possible; however...... semantics”, in such a way that all observed similarities can be satisfactorily explained using the latent semantics. Therefore, one can think of these semantics as the real structure in music, in the sense that they can explain the observed similarities among songs. The suitability of the PLSA model...

  19. Discovering Music Structure via Similarity Fusion

    DEFF Research Database (Denmark)

    Arenas-García, Jerónimo; Parrado-Hernandez, Emilio; Meng, Anders

    Automatic methods for music navigation and music recommendation exploit the structure in the music to carry out a meaningful exploration of the “song space”. To get a satisfactory performance from such systems, one should incorporate as much information about songs similarity as possible; however...... semantics”, in such a way that all observed similarities can be satisfactorily explained using the latent semantics. Therefore, one can think of these semantics as the real structure in music, in the sense that they can explain the observed similarities among songs. The suitability of the PLSA model...... for representing music structure is studied in a simplified scenario consisting of 4412 songs and two similarity measures among them. The results suggest that the PLSA model is a useful framework to combine different sources of information, and provides a reasonable space for song representation....

  20. Nuclear structure in cold rearrangement processes in fission and fusion

    Energy Technology Data Exchange (ETDEWEB)

    Armbruster, P.

    1998-11-01

    In fission and fusion of heavy nuclei large numbers of nucleons are rearranged at a scale of excitation energy very small compared to the binding energy of the nuclei. The energies involved are less than 40 MeV at nuclear temperatures below 1.5 MeV. The shapes of the configurations in the rearrangement of a binary system into a monosystem in fusion, or vice versa in fission, change their elongations by as much as 8 fm, the radius of the monosystem. The dynamics of the reactions macroscopically described by a potential energy surface, inertia parameters, dissipation, and a collision energy is strongly modified by the nuclear structure of the participating nuclei. Experiments showing nuclear structure effects in fusion and fission of the heaviest nuclei are reviewed. The reaction kinematics and the multitude of isotopes involved are investigated by detector techniques and by recoil spectrometers. The advancement of the latter allows to find very small reaction branches in the range of 10{sup -5} to 10{sup -10}. The experiments reveal nuclear structure effects in all stages of the rearrangement processes. These are discussed pointing to analogies in fusion and fission on the microscopic scale, notwithstanding that both processes macroscopically are irreversible. Heavy clusters, as 132Sn, 208Pb, nuclei with closed shell configurations N=82,126, Z=50,82 survive in large parts of the nuclear rearrangement. They determine the asymmetry in the mass distribution of low energy fission, and they allow to synthesise superheavy elements, until now up to element 112. Experiments on the cold rearrangement in fission and fusion are presented. Here, in the range of excitation energies below 12 MeV the phenomena are observed most convincingly. (orig.)

  1. Fusion welding of Fe-added lap joints between AZ31B magnesium alloy and 6061 aluminum alloy by hybrid laser-tungsten inert gas welding technique

    International Nuclear Information System (INIS)

    Qi, Xiao-dong; Liu, Li-ming

    2012-01-01

    Highlights: → Hybrid Laser-TIG fusion welding technique was used for joining Mg to Al alloys. → Laser defocusing amount determined penetration depth inside Al alloy of joints. → The addition of Fe interlayer suppressed Mg-Al intermetallics greatly in joints. → A maximum joint strength with optimum thickness of Fe interlayer was obtained. → Excessive addition of Fe interlayer was adverse for the strength improvement. -- Abstract: AZ31B magnesium alloy and 6061-T6 aluminum alloy were lap joined together with the addition of Fe interlayer by fusion welding of hybrid laser-tungsten inert gas (TIG) technique. The influence of location of laser focal spot (LFS) on joint penetration depth and that of the depth on joint strength were investigated. The results showed that when the LFS was just on the surface of Al plate, the deepest penetration could be obtained, which contributed to the improvement of shear strength of Fe-added joints, but not to the elevation of the strength of Mg/Al direct joints. The addition of Fe interlayer suppressed massive production of Mg-Al intermetallics but produced Fe-Al intermetallics in the fusion zone of the joints, whose micro-hardness was extremely high and was also adverse for the enhancement of joint shear strength. The effect of Fe-interlayer thickness on the joint shear strength was also examined, and the maximum shear strength of Fe-added joint could achieve 100 MPa with 0.13 mm thick Fe interlayer. The fracture modes of 0.07 and 0.13 mm Fe-interlayer-added joints were both quasi-cleavage, while those of direct and 0.22 mm interlayer-added joints were completely cleavage. The theoretical shear strength of the Fe-added joints was also discussed.

  2. Advances in aluminium alloy products for structural applications in transportation

    International Nuclear Information System (INIS)

    Staley, J.T.; Lege, D.J.

    1993-01-01

    This paper describes the needs of the aviation and automotive markets for structural materials and presents examples of developments of aluminum alloy products to fill these needs. Designers of aircraft desire materials which will allow them to design lightweight, cost-effective structures which have the performance characteristics of durability and damage tolerance. Their needs are being met by new and emerging materials varying from Al-Li alloys for thick structure, high-strength plate and extrusions for wings, and new monolithic and aluminum-fiber laminates for fuselages. Increase in fuel economy because of lighter weight structure is the driving force for aluminum alloys in the automotive market, and cost is extremely important. Mechanical properties for automotive use also depend on the application, and corrosion resistance must be adequate. For ''hang-on'' components such as fenders and hoods, formability is typically the limiting mechanical property. Strength must be adequate to resist denting at a thickness which offers cost-effective weight savings over steel. Because formability often decreases with increasing yield strength, alloys which are highly formable in the T4 temper and which age harden during the paint bake operation were developed. Alloys such as 6009 and 6010 are now being challenged by 2008, 6111 and 6016. Body structure components must be made from materials which absorb energy and fail gracefully during a crash. Such components for an automotive space frame are being die cast from an Al-Si-Mg alloy. These ductile die castings are joined to thin 6XXX extrusions which must combine formability, strength, ductility and the ability to deform plastically on impact. Bumpers must combine strength and adequate formability; in the event that current alloys are inadequate for future needs, a new 7XXX alloy offers an improved combination of properties. (orig.)

  3. PDF analysis of PuAl alloys local structure

    Energy Technology Data Exchange (ETDEWEB)

    Platteau, C. [CEA Valduc, 21120 Is-sur-Tille (France)], E-mail: platteau.cyril@yahoo.fr; Bruckel, P.; Ravat, B.; Delaunay, F. [CEA Valduc, 21120 Is-sur-Tille (France)

    2009-03-15

    For understanding singular properties of plutonium, there is a need in studying the average and local atomic structure in Pu alloys. To study the local structure of the {delta} phase, a pair distribution function (PDF) analysis was done and has shown some significant differences with the average structure.

  4. Unveiling Music Structure Via PLSA Similarity Fusion

    DEFF Research Database (Denmark)

    Arenas-García, Jerónimo; Meng, Anders; Petersen, Kaare Brandt

    2007-01-01

    Nowadays there is an increasing interest in developing methods for building music recommendation systems. In order to get a satisfactory performance from such a system, one needs to incorporate as much information about songs similarity as possible; however, how to do so is not obvious. In this p......Nowadays there is an increasing interest in developing methods for building music recommendation systems. In order to get a satisfactory performance from such a system, one needs to incorporate as much information about songs similarity as possible; however, how to do so is not obvious...... observed similarities can be satisfactorily explained using the latent semantics. Additionally, this approach significantly simplifies the song retrieval phase, leading to a more practical system implementation. The suitability of the PLSA model for representing music structure is studied in a simplified...

  5. Discontinuous structural phase transition of liquid metal and alloys (2)

    International Nuclear Information System (INIS)

    Wang, Li; Liu, Jiantong

    2004-01-01

    The diameter (d f ) of diffusion fluid cluster before and after phase transition has been calculated in terms of the paper ''Discontinuous structural phase transition of liquid metal and alloy (1)'' Physics Letters. A 326 (2004) 429-435, to verify quantitatively the discontinuity of structural phase transition; the phenomena of thermal contraction and thermal expansion during the phase transition, together with the evolution model of discontinuous structural phase transition are also discussed in this Letter to explore further the nature of structural transition; In addition, based on the viscosity experimental result mentioned in paper [Y. Waseda, The Structure of Non-Crystalline Materials--Liquids and Amorphous Solids, McGraw-Hill, New York, 1980], we present an approach to draw an embryo of the liquid-liquid (L-L) phase diagram for binary alloys above liquidus in the paper, expecting to guide metallurgy process so as to improve the properties of alloys. The idea that controls amorphous structure and its properties by means of the L-L phase diagram for alloys and by the rapid cooling technique to form the amorphous alloy has been brought forward in the end

  6. Transmutation and activation of fusion reactor wall and structural materials

    International Nuclear Information System (INIS)

    Jarvis, O.N.

    1979-01-01

    This report details the extent of the nuclear data needed for inclusion in a data library to be used for general assessments of fusion reactor structure activation and transmutation, describes the sources of data available, reviews the literature and explores the reliability of current calculations by providing an independent assessment of the activity inventory to be expected from five structural materials in a simple blanket design for comparison with the results of other workers. An indication of the nuclear reactions which make important contributions to the activity, transmutation and gas production rates for these structural materials is also presented. (author)

  7. The speciation of Si and other alloying elements in the oxide surface film of galvanically corroded weld fusion zone of laser welded AA6061 aluminium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Mujibur Rahman, A.B.M.; Kumar, Sunil [Ian Wark Research Institute, University of South Australia, Mawson Lakes Campus, Mawson Lakes, South Australia 5095 (Australia); Gerson, Andrea R. [Applied Centre for Structural and Synchrotron Studies, University of South Australia, Mawson Lakes Campus, Mawson Lakes, South Australia 5095 (Australia)], E-mail: Andrea.Gerson@unisa.edu.au

    2008-05-15

    It has recently been proposed that on galvanic corrosion of laser weldments of AA6061 aluminium alloy the temporal increase in galvanic corrosion resulted from either the build up of intermetallic phases in the surface oxide layer and/or a significant increase in the surface area of the cathodic weld fusion zone due to the porous nature of the surface layer. This proposition has motivated a comprehensive surface analytical study of the incorporation of alloying elements into the oxide surface film, which is composed predominately of alumina. Si is found to be present as silicate and silicides. The Gibbs free energy of formation, per cation, of silicate is more negative than that for alumina and hence silicate formation is thermodynamically, relatively, favourable. In contrast the Gibbs free energy for oxide formation, per cation, for the other alloying elements is less negative and hence relatively unfavourable compared to the formation of alumina. We propose therefore that Fe, Cu and Cr are present in the metallic form, possibly as silicides, within the oxide surface layer. Magnesium is found to be depleted relative to the weld fusion zone presumably due to dissolution within the electrolyte.

  8. The speciation of Si and other alloying elements in the oxide surface film of galvanically corroded weld fusion zone of laser welded AA6061 aluminium alloy

    International Nuclear Information System (INIS)

    Mujibur Rahman, A.B.M.; Kumar, Sunil; Gerson, Andrea R.

    2008-01-01

    It has recently been proposed that on galvanic corrosion of laser weldments of AA6061 aluminium alloy the temporal increase in galvanic corrosion resulted from either the build up of intermetallic phases in the surface oxide layer and/or a significant increase in the surface area of the cathodic weld fusion zone due to the porous nature of the surface layer. This proposition has motivated a comprehensive surface analytical study of the incorporation of alloying elements into the oxide surface film, which is composed predominately of alumina. Si is found to be present as silicate and silicides. The Gibbs free energy of formation, per cation, of silicate is more negative than that for alumina and hence silicate formation is thermodynamically, relatively, favourable. In contrast the Gibbs free energy for oxide formation, per cation, for the other alloying elements is less negative and hence relatively unfavourable compared to the formation of alumina. We propose therefore that Fe, Cu and Cr are present in the metallic form, possibly as silicides, within the oxide surface layer. Magnesium is found to be depleted relative to the weld fusion zone presumably due to dissolution within the electrolyte

  9. Hemi-fused structure mediates and controls fusion and fission in live cells.

    Science.gov (United States)

    Zhao, Wei-Dong; Hamid, Edaeni; Shin, Wonchul; Wen, Peter J; Krystofiak, Evan S; Villarreal, Seth A; Chiang, Hsueh-Cheng; Kachar, Bechara; Wu, Ling-Gang

    2016-06-23

    Membrane fusion and fission are vital for eukaryotic life. For three decades, it has been proposed that fusion is mediated by fusion between the proximal leaflets of two bilayers (hemi-fusion) to produce a hemi-fused structure, followed by fusion between the distal leaflets, whereas fission is via hemi-fission, which also produces a hemi-fused structure, followed by full fission. This hypothesis remained unsupported owing to the lack of observation of hemi-fusion or hemi-fission in live cells. A competing fusion hypothesis involving protein-lined pore formation has also been proposed. Here we report the observation of a hemi-fused Ω-shaped structure in live neuroendocrine chromaffin cells and pancreatic β-cells, visualized using confocal and super-resolution stimulated emission depletion microscopy. This structure is generated from fusion pore opening or closure (fission) at the plasma membrane. Unexpectedly, the transition to full fusion or fission is determined by competition between fusion and calcium/dynamin-dependent fission mechanisms, and is notably slow (seconds to tens of seconds) in a substantial fraction of the events. These results provide key missing evidence in support of the hemi-fusion and hemi-fission hypothesis in live cells, and reveal the hemi-fused intermediate as a key structure controlling fusion and fission, as fusion and fission mechanisms compete to determine the transition to fusion or fission.

  10. Development and prevention of porosity in the fusion welding of thick titanium alloys

    International Nuclear Information System (INIS)

    Kulikov, F.R.; Redchits, V.V.; Khokhlov, V.V.

    1975-01-01

    This article describes the results of experimental investigations of the mechanics of formation of porosity in electron-beam welding, single-pass and multipass welding in argon with a consumable and non-consumable electrode, and also in the electroslag welding of alloys VT14 and VT22 from 10 to 60mm thick. It was established that nuclei of gas phase form at the moment of fusion of the edges of the parts being welded, the end surfaces of which have machining defects. The weld metal porosity can be prevented by: careful machining of the faying surfaces of the parts to be welded immediately before welding; the use of welding conditions ensuring long pool existence time, sufficient for hydrogen bubbles to float up and escape; intensification of the weld pool degassing process by using fluxes based on metal fluorides and chlorides, applied to the ends of the root part of the faying edges, and on the filler wire; reduction of the gas pressure in the beam channel by making gas-escape paths

  11. Periodic Cellular Structure Technology for Shape Memory Alloys

    Science.gov (United States)

    Chen, Edward Y.

    2015-01-01

    Shape memory alloys are being considered for a wide variety of adaptive components for engine and airframe applications because they can undergo large amounts of strain and then revert to their original shape upon heating or unloading. Transition45 Technologies, Inc., has developed an innovative periodic cellular structure (PCS) technology for shape memory alloys that enables fabrication of complex bulk configurations, such as lattice block structures. These innovative structures are manufactured using an advanced reactive metal casting technology that offers a relatively low cost and established approach for constructing near-net shape aerospace components. Transition45 is continuing to characterize these structures to determine how best to design a PCS to better exploit the use of shape memory alloys in aerospace applications.

  12. Recent advances in alloy design of Ni{sub 3}Al alloys for structural use

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.T.; George, E.P.

    1996-12-31

    This is a comprehensive review of recent advances in R&D of Ni{sub 3}Al-based alloys for structural use at elevated temperatures in hostile environments. Recent studies indicate that polycrystalline Ni{sub 3}Al is intrinsically quite ductile at ambient temperatures, and its poor tensile ductility and brittle grain-boundary fracture are caused mainly by moisture-induced hydrogen embrittlement when the aluminide is tested in moisture- or hydrogen-containing environments. Tensile ductility is improved by alloying with substitutional and interstitial elements. Among these additives, B is most effective in suppressing environmental embrittlement and enhancing grain-boundary cohesion, resulting in a dramatic increase of tensile ductility at room temperature. Both B-doped and B-free Ni{sub 3}Al alloys exhibit brittle intergranular fracture and low ductility at intermediate temperatures (300-850 C) because of oxygen-induced embrittlement in oxidizing environments. Cr is found to be most effective in alleviating elevated-temperature embrittlement. Parallel efforts on alloy development using physical metallurgy principles have led to development of several Ni{sub 3}Al alloys for industrial use. The unique properties of these alloys are briefly discussed. 56 refs, 15 figs, 3 tabs.

  13. Compatibility of structural materials with fusion reactor coolant and breeder fluids

    International Nuclear Information System (INIS)

    DeVan, J.H.

    1979-01-01

    Fusion reactors are characterized by a lithium-containing blanket, a heat transfer medium that is integral with the blanket and first wall, and a heat engine that couples to the heat transfer medium. A variety of lithium-containing substances have been identified as potential blanket materials, including molten lithium metal, molten LiF-BeF 2 , Pb-Li alloys, and solid ceramic compounds such as Li 2 O. Potential heat transfer media include liquid lithium, liquid sodium, molten nitrates, water, and helium. Each of these coolants and blankets requires a particular set of chemical and mechanical properties with respect to the associated reactor and heat engine structural materials. This paper discusses the materials factors that underlie the selection of workable combinations of blankets and coolants. It also addresses the materials compatibility problems generic to those blanket-coolant combinations currently being considered in reactor design studies. (orig.)

  14. Plasma exposure behavior of re-deposited tungsten on structural materials of fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yu-Ping; Wang, Jing [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Science Island Branch of Graduate School, University of Science & Technology of China, Hefei 230031 (China); Zhou, Hai-Shan, E-mail: haishanzhou@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Liu, Feng [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Li, Zeng-De [General Research Institute for Nonferrous Metals, Beijing 100088 (China); Li, Xiao-Chun; Lu, Tao [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Liu, Hao-Dong [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Science Island Branch of Graduate School, University of Science & Technology of China, Hefei 230031 (China); Ding, Fang; Mao, Hong-Min; Zhao, Ming-Zhong [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Lin, Chen-Guang [General Research Institute for Nonferrous Metals, Beijing 100088 (China); Luo, Guang-Nan [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Science Island Branch of Graduate School, University of Science & Technology of China, Hefei 230031 (China); Hefei Center for Physical Science and Technology, Hefei 230031 (China); Hefei Science Center of Chinese Academy of Science, Hefei 230027 (China)

    2017-05-15

    To evaluate the effects of re-deposited tungsten (W) on the surface modification and hydrogen isotope retention behavior of fusion structural materials, the plasma exposure behavior of re-deposited W samples prepared by magnetron sputtering on the F82H steel, the V-5Cr-5Ti alloy as well as bare substrate samples was investigated. All the samples were exposed to 367 shots of deuterium plasmas in the 2015 spring EAST campaign. After the plasma exposure, large area of W layer was exfoliated, while big blisters were found at the interface between the remaining W layer and the substrate materials. The deuterium retention behavior of the samples with re-deposited W layer was characterized by thermal desorption spectroscopy and compared with the bare substrate samples.

  15. Legirani praški za navarjanje z večžično elektrodo: Alloyed fluxes for surfacing with multiple - wire electrode:

    OpenAIRE

    Kejžar, Božena; Kejžar, Rajko

    1997-01-01

    Submerged arc surfacing with alloyed agglomerated fluxes permits unalloyed and low-alloy structural steels to be surfaced in one layer of high-alloyed claddings. Surfacing dilution produced by fusion of the parent metal, and burn-off of alloying elements are substituted by additional alloying by means of a welding flux, which is, in the case of the above-mentioned surfacing processes, the main carrier of alloying elements for surfacing alloying. With alloyed agglomerated fluxes, it is recomme...

  16. Fragility and structure of Al-Cu alloy melts

    International Nuclear Information System (INIS)

    Lv Xiaoqian; Bian Xiufang; Mao Tan; Li Zhenkuan; Guo Jing; Zhao Yan

    2007-01-01

    The dynamic viscosity measurements are performed for Al-Cu alloy melts with different compositions using an oscillating-cup viscometer. The results show that the viscosities of Al-Cu alloy melts increase with the copper content increasing, and also have a correlation with the correlation radius of clusters, which is measured by the high-temperature X-ray diffractometer. It has also been found that the fragilities of superheated melts (M) of hypereutectic Al-Cu alloys increase with the copper content increasing. There exists a relationship between the fragility and the structure in Al-Cu alloy melts. The value of the M reflects the variation of activation energy for viscous flow

  17. Helium effect on mechanical property of fusion reactor structural materials

    International Nuclear Information System (INIS)

    Yamamoto, Norikazu; Chuto, Toshinori; Murase, Yoshiharu; Nakagawa, Johsei

    2004-01-01

    High-energy neutrons produced in fusion reactor core caused helium in the structural materials of fusion reactors, such as blankets. We injected alpha particles accelerated by the cyclotron to the samples of martensite steel (9Cr3WVTaB). Equivalent helium doses injected to the sample is estimated to be up to 300 ppm, which were estimated to be equivalent to helium accumulation after the 1-year reactor operation. Creep tests of the samples were made to investigate helium embrittlement. There were no appreciable changes in the relation between the stresses and the rupture time, the minimum creep rate and the applied stress. Grain boundary effect by helium was not observed in ruptured surfaces. Fatigue tests were made for SUS304 samples, which contain helium up to 150 ppm. After 0.05 Hz cyclic stress tests, it was shown that the fatigue lifetime (cycles to rupture and extension to failure) are 1/5 in 150 ppm helium samples compared with no helium samples. The experimental results suggest martensite steel is promising for structural materials of fusion reactors. (Y. Tanaka)

  18. Fatigue damage monitoring of structural aluminum alloys

    Directory of Open Access Journals (Sweden)

    С.Р. Ігнатович

    2004-01-01

    Full Text Available  Results of the experiments directed on creation of a new tool method of fatigue damage diagnostics and an estimation of a residual life of aviation designs are presented. It is shown, that the defo rmation relief formed on a surface of cladding  layer of sheets of constructional alloys Д-16АТ, 2024-Т3, 7075-Т6  can be considered as the metal damage indicator  under cyclically repeating loadings.

  19. The use of folding structures in fusion reactors

    International Nuclear Information System (INIS)

    Haines, T.

    1992-01-01

    Folding structures can be used with advantage in fusion machines. They have been used in Space for decades to extend antennas, sensors and solar panels; terrestrial versions have been used as retractable antennas and antennas masts. They have also been used in the Joint European Torus (JET) and other nuclear applications. In this paper, three types are described, together with concepts for use in fusion machines. The Storable Tubular Extendible Member (STEM) was conceived by the National Research Council of Canada and developed by Spar Aerospace Limited. The Astromast is a folding truss developed by Astro Aerospace Corporation, a US subsidiary of Spar. The X-Beam is an ultra-stiff folding truss

  20. Study of structural relaxation in amorphous alloys prepared by sputtering

    International Nuclear Information System (INIS)

    Habibi, S.; Banaee, N.; Majidy, S.

    2004-01-01

    Full text: We have prepared amorphous alloy of Al x Cu 1-x (with X= 93, 90, 80, 70, 30) using sputtering system. The rate of growth was 0.7 nm/sec. X-ray diffractometer was used to conform the amorphous nature of the prepared specimens. High temperature annealing can change amorphous to crystalline structure, while low temperature annealing may transform amorphous state to a more stable amorphous state via structural relaxation of the specimen and enhancing the properties of the alloys, such as mechanical ductility etc. Here we have annealed the alloys at temperatures 100, 150, 200, 250, 300 and 350 C for 1 hour. We observed that microhardness of the specimen increases with annealing and gets maximum value at 300 C. Our XRD experiments and also earlier Moessbauer studies show that while the average interatomic distances reduces due to annealing, structure remains amorphous

  1. Structural disordering of de-alloyed Pt bimetallic nanocatalysts

    DEFF Research Database (Denmark)

    Spanos, Ioannis; Dideriksen, Knud; Kirkensgaard, Jacob Judas Kain

    2015-01-01

    composition affects their electrocatalytic performance. The results show that upon contact with acid environment the Co leaches out of the particles leading to almost identical compositions, independent of the initial differences. Surprisingly the data show a clear trend in ORR activity, although the PtxCo1-x...... nanoparticles almost completely de-alloy during acid leaching, i.e. under reaction conditions in a fuel cell. To scrutinize the resulting particle structure after de-alloying we used pair distribution function (PDF) analysis and X-ray diffraction (XRD) gaining insight into the structural disorder and its...... dependence on the initial metal composition. Our results suggest that not only the ORR activity, but also the corrosion resistance of the synthesized NPs, are dependent on the structural disorder resulting from the de-alloying process....

  2. Neurovascular Structures at Risk With Curved Retrograde TTC Fusion Nails.

    Science.gov (United States)

    de Cesar Netto, Cesar; Johannesmeyer, David; Cone, Brent; Araoye, Ibukunoluwa; Hudson, Parke William; Sahranavard, Bahman; Johnson, Michael; Shah, Ashish

    2017-10-01

    The purpose of this study was to assess the risk of iatrogenic injury to plantar neurovascular structures of the foot during insertion of a curved retrograde tibiotalocalcaneal (TTC) fusion nail. Ten below-knee thawed fresh-frozen cadaveric specimens underwent curved retrograde nailing of the ankle. The shortest distance between the nail and the main plantar neurovascular branches and injured structures were recorded during dissection. We also evaluated the relative position of these structures along 2 lines (AB, connecting the calcaneus to the first metatarsal, and BC, connecting the first and fifth metatarsal). The lateral plantar artery was found to be in direct contact with the nail 70% of the time, with a macroscopic laceration 30% of the time. The Baxter nerve was injured 20% of the time, as was the lateral plantar nerve. The medial plantar artery and nerve were never injured. The most proximal structure to cross line AB was the Baxter nerve followed by the lateral plantar artery, the nail, the lateral plantar nerve, and the medial plantar nerve. Our cadaveric anatomic study found that the most common structures at risk for iatrogenic injury by lateral curved retrograde TTC fusion nails were the lateral plantar artery and nerve, and the Baxter nerve. Determination of a true neurovascular safe zone is challenging and therefore warrants careful operative dissection to minimize neurovascular injuries.

  3. On the use of tin-lithium alloys as breeder material for blankets of fusion power plants

    International Nuclear Information System (INIS)

    Fuetterer, M.A.; Aiello, G.; Barbier, F.; Giancarli, L.; Poitevin, Y.; Sardain, P.; Szczepanski, J.; Li Puma, A.; Ruvutuso, G.; Vella, G.

    2000-01-01

    Tin-lithium alloys have several attractive thermo-physical properties, in particular high thermal conductivity and heat capacity, that make them potentially interesting candidates for use in liquid metal blankets. This paper presents an evaluation of the advantages and drawbacks caused by the substitution of the currently employed alloy lead-lithium (Pb-17Li) by a suitable tin-lithium alloy: (i) for the European water-cooled Pb-17Li (WCLL) blanket concept with reduced activation ferritic-martensitic steel as the structural material; (ii) for the European self-cooled TAURO blanket with SiC f /SiC as the structural material. It was found that in none of these blankets Sn-Li alloys would lead to significant advantages, in particular due to the low tritium breeding capability. Only in forced convection cooled divertors with W-alloy structure, Sn-Li alloys would be slightly more favorable. It is concluded that Sn-Li alloys are only advantageous in free surface cooled reactor internals, as this would make maximum use of the principal advantage of Sn-Li, i.e., the low vapor pressure

  4. Alloy development for fast induced radioactivity decay for fusion reactor applications

    International Nuclear Information System (INIS)

    Klueh, R.L.; Bloom, E.E.

    1984-03-01

    The Cr-Mo ferritic (martensitic) steels and austenitic stainless steels (primarily type 316 and variations on that composition) are the leading candidates for the structural components for future fusion reactors. However, irradiation of such steels in a fusion environment produces long-lived radioactive isotopes. These isotopes lead to difficult radioactive waste disposal problems once the structure is removed from service. Such problems could be reduced by developing steels that contain only elements that produce radioactive isotopes that decay to low levels in a reasonable time (tens of years instead of hundreds or thousands of years). This report discusses the development of such steels by making elemental substitutions in the steels now under consideration. Molybdenum must be replaced in the Cr-Mo steels; nickel and molybdenum both must be replaced in the austenitic stainless steels (the nitrogen concentration must be limited, and niobium, maintained to extremely low levels). Appropriate substitutions are tungsten for molybdenum in the Cr-Mo steels and manganese for nickel in the austenitic stainless steels. Indications are that suitable ferritic steels can be developed, but development of a nickel-free austenitic stainless steel with properties similar to the Cr-Ni stainless steels appears to be much more complex

  5. Microstructure evolution in the fusion zone of laser-welded Mg–Gd–Y–Zr alloy during solution and aging treatment

    International Nuclear Information System (INIS)

    Wang, Lyuyuan; Huang, Jian; Dong, Jie; Feng, Kai; Wu, Yixiong; Chu, Paul K.

    2016-01-01

    The microstructure evolution in the fusion zone of laser-welded Mg-Gd-Y-Zr alloy during solution and aging treatment is investigated. The morphology of the Mg 24 (Gd,Y) 5 in the divorced eutectic at the grain boundary transforms from a continuous network to disconnected and fragmentized islands and then to spheroidal particles before complete dissolution during the solution treatment at 430 °C. During the subsequent aging treatment at 225 °C, the precipitation sequence in the fusion zone follows the order of supersaturated solid solution (SSSS) → βʺ(D0 19 ) → βʹ(cbco) → β 1 (fcc) → β(fcc). High-density precipitates are present at the original grain boundaries of the fusion zone from the welded structure but there are less precipitates in the interior of the original grains. The grain growth during the solution treatment at 430 °C comprises the slowly increasing stage, rapidly increasing stage, and stable stage. The network-distributed Mg 24 (Gd,Y) 5 impedes migration of the grain boundaries, restricts grain growth in the first slowly increasing stage, and segregation of zirconium near the grain boundaries also affects migration of the grain boundaries. - Highlights: •Different quantities of precipitates are present at different location of grain. •The network-distributed Mg 24 (Gd,Y) 5 restricts grain growth. •Segregation of Zr affects migration of grain boundaries.

  6. The experimental search for new predicted binary-alloy structures

    Science.gov (United States)

    Erb, K. C.; Richey, Lauren; Lang, Candace; Campbell, Branton; Hart, Gus

    2010-10-01

    Predicting new ordered phases in metallic alloys is a productive line of inquiry because configurational ordering in an alloy can dramatically alter their useful material properties. One is able to infer the existence of an ordered phase in an alloy using first-principles calculated formation enthalpies.ootnotetextG. L. W. Hart, ``Where are Nature's missing structures?,'' Nature Materials 6 941-945 2007 Using this approach, we have been able to identify stable (i.e. lowest energy) orderings in a variety of binary metallic alloys. Many of these phases have been observed experimentally in the past, though others have not. In pursuit of several of the missing structures, we have characterized potential orderings in PtCd, PtPd and PtMo alloys using synchrotron x-ray powder diffraction and symmetry-analysis tools.ootnotetextB. J. Campbell, H. T. Stokes, D. E. Tanner, and D. M. Hatch, ``ISODISPLACE: a web-based tool for exploring structural distortions,'' J. Appl. Cryst. 39, 607-614 (2006)

  7. Electronic structure and phase equilibria in ternary substitutional alloys

    International Nuclear Information System (INIS)

    Traiber, A.J.S.; Allen, S.M.; Waterstrat, R.M.

    1996-01-01

    A reliable, consistent scheme to study phase equilibria in ternary substitutional alloys based on the tight-binding approximation is presented. With electronic parameters from linear muffin-tin orbital calculations, the computed density of states and band structures compare well with those from more accurate abinitio calculations. Disordered alloys are studied within the tight-binding coherent-potential approximation extended to alloys; energetics of ordered systems are obtained through effective pair interactions computed with the general perturbation method; and partially ordered alloys are studied with a novel simplification of the molecular coherent-potential approximation combined with the general perturbation method. The formalism is applied to bcc-based Zr-Ru-Pd alloys which are promising candidates for medical implant devices. Using energetics obtained from the above scheme, we apply the cluster- variation method to study phase equilibria for particular pseudo- binary alloys and show that results are consistent with observed behavior of electronic specific heat coefficient with composition for Zr 0.5 (Ru, Pd) 0.5

  8. Electron microscopy study of hardened layers structure at electrospark alloying the VT-18 titanium alloy with aluminium

    International Nuclear Information System (INIS)

    Pilyankevich, A.N.; Martynenko, A.N.; Verkhoturov, A.D.; Paderno, V.N.

    1979-01-01

    Presented are the results of metallographic, electron-microscopic, and X-ray structure analysis, of microhardness measurements and of the study of the electrode weight changes at electrospark alloying the VT-18 titanium alloy with aluminium. It is shown, that pulsating thermal and mechanical loadings in the process of electrospark alloying result in the electrode surface electroerosion, a discrete relief is being formed, which changes constantly in the process depending on the alloying time. Though with the process time the cathode weight gain increases, microareas of fracture in the hardened layer appear already at the initial stages of electrospark alloying

  9. Fusion reactor materials

    Energy Technology Data Exchange (ETDEWEB)

    none,

    1989-01-01

    This paper discuses the following topics on fusion reactor materials: irradiation, facilities, test matrices, and experimental methods; dosimetry, damage parameters, and activation calculations; materials engineering and design requirements; fundamental mechanical behavior; radiation effects; development of structural alloys; solid breeding materials; and ceramics.

  10. Fusion reactor materials

    International Nuclear Information System (INIS)

    1989-01-01

    This paper discuses the following topics on fusion reactor materials: irradiation, facilities, test matrices, and experimental methods; dosimetry, damage parameters, and activation calculations; materials engineering and design requirements; fundamental mechanical behavior; radiation effects; development of structural alloys; solid breeding materials; and ceramics

  11. Nano-structureal and nano-chemical analysis of Ni-based alloy/low alloy steel dissimilar metal weld interfaces

    International Nuclear Information System (INIS)

    Choi, Kyoung Joon; Shin, Sang Hun; Kim, Jong Jin; Jung, Ju Ang; Kim, Ji Hyun

    2012-01-01

    The dissimilar metal joints welded between Ni-based alloy, Alloy 690 and low alloy steel, A533 Gr. B with Alloy 152 filler metal were characterized by using optical microscope, scanning electron microscope, transmission electron microscope, secondary ion mass spectrometry and 3-dimensional atom probe tomography. It was found that in the weld root region, the weld was divided into several regions including unmixed zone in Ni-base alloy, fusion boundary, and heat-affected zone in the low alloy steel. The result of nanostructural and nanochemical analyses in this study showed the non-homogeneous distribution of elements with higher Fe but lower Mn, Ni and Cr in A533 Gr. B compared with Alloy 152, and the precipitation of carbides near the fusion boundary.

  12. Nano-structureal and nano-chemical analysis of Ni-based alloy/low alloy steel dissimilar metal weld interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kyoung Joon; Shin, Sang Hun; Kim, Jong Jin; Jung, Ju Ang; Kim, Ji Hyun [Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology (UNIST), Ulsan (Korea, Republic of)

    2012-06-15

    The dissimilar metal joints welded between Ni-based alloy, Alloy 690 and low alloy steel, A533 Gr. B with Alloy 152 filler metal were characterized by using optical microscope, scanning electron microscope, transmission electron microscope, secondary ion mass spectrometry and 3-dimensional atom probe tomography. It was found that in the weld root region, the weld was divided into several regions including unmixed zone in Ni-base alloy, fusion boundary, and heat-affected zone in the low alloy steel. The result of nanostructural and nanochemical analyses in this study showed the non-homogeneous distribution of elements with higher Fe but lower Mn, Ni and Cr in A533 Gr. B compared with Alloy 152, and the precipitation of carbides near the fusion boundary.

  13. Electron Beam Freeform Fabrication of Titanium Alloy Gradient Structures

    Science.gov (United States)

    Brice, Craig A.; Newman, John A.; Bird, Richard Keith; Shenoy, Ravi N.; Baughman, James M.; Gupta, Vipul K.

    2014-01-01

    Historically, the structural optimization of aerospace components has been done through geometric methods. A monolithic material is chosen based on the best compromise between the competing design limiting criteria. Then the structure is geometrically optimized to give the best overall performance using the single material chosen. Functionally graded materials offer the potential to further improve structural efficiency by allowing the material composition and/or microstructural features to spatially vary within a single structure. Thus, local properties could be tailored to the local design limiting criteria. Additive manufacturing techniques enable the fabrication of such graded materials and structures. This paper presents the results of a graded material study using two titanium alloys processed using electron beam freeform fabrication, an additive manufacturing process. The results show that the two alloys uniformly mix at various ratios and the resultant static tensile properties of the mixed alloys behave according to rule-of-mixtures. Additionally, the crack growth behavior across an abrupt change from one alloy to the other shows no discontinuity and the crack smoothly transitions from one crack growth regime into another.

  14. Electronic structure calculations on nitride semiconductors and their alloys

    International Nuclear Information System (INIS)

    Dugdale, D.

    2000-09-01

    Calculations of the electronic properties of AIN, GaN, InN and their alloys are presented. Initial calculations are performed using the first principles pseudopotential method to obtain accurate lattice constants. Further calculations then investigate bonding in the nitrides through population analysis and density of state calculations. The empirical pseudopotential method is also used in this work. Pseudopotentials for each of the nitrides are constructed using a functional form that allows strained material and alloys to be studied. The conventional k.p valence band parameters for both zincblende and wurtzite are obtained from the empirical band structure using two different methods. A Monte-Carlo fitting of the k.p band structure to the pseudopotential data (or an effective mass method for the zincblende structure) is used to produce one set. Another set is obtained directly from the momentum matrix elements and energy eigenvalues at the centre of the Brillouin zone. Both methods of calculating k.p parameters produce band structure in excellent agreement with the original empirical band calculations near the centre of the Brillouin zone. The advantage of the direct method is that it produces consistent sets of parameters, and can be used in studies involving a series of alloy compositions. Further empirical pseudopotential method calculations are then performed for alloys of the nitrides. In particular, the variation of the band gap with alloy composition is investigated, and good agreement with theory and experiment is found. The direct method is used to obtain k.p parameters for the alloys, and is contrasted with the fitting approach. The behaviour of the nitrides under strain is also studied. In particular. valence band offsets for nitride heterojunctions are calculated, and a strong forward- backward asymmetry in the band offset is found, in good agreement with other results in the literature. (author)

  15. Microstructural Evolution and Creep-Rupture Behavior of Fusion Welds Involving Alloys for Advanced Ultrasupercritical Power Generation

    Science.gov (United States)

    Bechetti, Daniel H., Jr.

    Projections for large increases in the global demand for electric power produced by the burning of fossil fuels, in combination with growing environmental concerns surrounding these fuel sources, have sparked initiatives in the United States, Europe, and Asia aimed at developing a new generation of coal fired power plant, termed Advanced Ultrasupercritical (A-USC). These plants are slated to operate at higher steam temperatures and pressures than current generation plants, and in so doing will offer increased process cycle efficiency and reduced greenhouse gas emissions. Several gamma' precipitation strengthened Ni-based superalloys have been identified as candidates for the hottest sections of these plants, but the microstructural instability and poor creep behavior (compared to wrought products) of fusion welds involving these alloys present significant hurdles to their implementation and a gap in knowledge that must be addressed. In this work, creep testing and in-depth microstructural characterization have been used to provide insight into the long-term performance of these alloys. First, an investigation of the weld metal microstructural evolution as it relates to creep strength reductions in A-USC alloys INCONELRTM 740, NIMONICRTM 263 (INCONEL and NIMONIC are registered trademarks of Special Metals Corporation), and HaynesRTM 282RTM (Haynes and 282 are registered trademarks of Haynes International) was performed. gamma'-precipitate free zones were identified in two of these three alloys, and their development was linked to the evolution of phases that precipitate at the expense of gamma'. Alloy 282 was shown to avoid precipitate free zone formation because the precipitates that form during long term aging in this alloy are poor in the gamma'-forming elements. Next, the microstructural evolution of INCONELRTM 740H (a compositional variant of alloy 740) during creep was investigated. Gleeble-based interrupted creep and creep-rupture testing was used to

  16. Three-Dimensional Cellular Structures Enhanced By Shape Memory Alloys

    Science.gov (United States)

    Nathal, Michael V.; Krause, David L.; Wilmoth, Nathan G.; Bednarcyk, Brett A.; Baker, Eric H.

    2014-01-01

    This research effort explored lightweight structural concepts married with advanced smart materials to achieve a wide variety of benefits in airframe and engine components. Lattice block structures were cast from an aerospace structural titanium alloy Ti-6Al-4V and a NiTi shape memory alloy (SMA), and preliminary properties have been measured. A finite element-based modeling approach that can rapidly and accurately capture the deformation response of lattice architectures was developed. The Ti-6-4 and SMA material behavior was calibrated via experimental tests of ligaments machined from the lattice. Benchmark testing of complete lattice structures verified the main aspects of the model as well as demonstrated the advantages of the lattice structure. Shape memory behavior of a sample machined from a lattice block was also demonstrated.

  17. Functionalization of Biomedical Ti6Al4V via In Situ Alloying by Cu during Laser Powder Bed Fusion Manufacturing

    Science.gov (United States)

    Krakhmalev, Pavel; Yadroitsev, Igor; Yadroitsava, Ina; de Smidt, Olga

    2017-01-01

    The modern medical industry successfully utilizes Laser Powder Bed Fusion (LPBF) to manufacture complex custom implants. Ti6Al4V is one of the most commonly used biocompatible alloys. In surgery practice, infection at the bone–implant interface is one of the key reasons for implant failure. Therefore, advanced implants with biocompatibility and antibacterial properties are required. Modification of Ti alloy with Cu, which in small concentrations is a proven non-toxic antibacterial agent, is an attractive way to manufacture implants with embedded antibacterial functionality. The possibility of achieving alloying in situ, during manufacturing, is a unique option of the LPBF technology. It provides unique opportunities to manufacture customized implant shapes and design new alloys. Nevertheless, optimal process parameters need to be established for the in situ alloyed materials to form dense parts with required mechanical properties. This research is dedicated to an investigation of Ti6Al4V (ELI)-1 at % Cu material, manufactured by LPBF from a mixture of Ti6Al4V (ELI) and pure Cu powders. The effect of process parameters on surface roughness, chemical composition and distribution of Cu was investigated. Chemical homogeneity was discussed in relation to differences in the viscosity and density of molten Cu and Ti6Al4V. Microstructure, mechanical properties, and fracture behavior of as-built 3D samples were analyzed and discussed. Pilot antibacterial functionalization testing of Ti6Al4V (ELI) in situ alloyed with 1 at % Cu showed promising results and notable reduction in the growth of pure cultures of Escherichia coli and Staphylococcus aureus. PMID:28972546

  18. Functionalization of Biomedical Ti6Al4V via In Situ Alloying by Cu during Laser Powder Bed Fusion Manufacturing

    Directory of Open Access Journals (Sweden)

    Pavel Krakhmalev

    2017-10-01

    Full Text Available The modern medical industry successfully utilizes Laser Powder Bed Fusion (LPBF to manufacture complex custom implants. Ti6Al4V is one of the most commonly used biocompatible alloys. In surgery practice, infection at the bone–implant interface is one of the key reasons for implant failure. Therefore, advanced implants with biocompatibility and antibacterial properties are required. Modification of Ti alloy with Cu, which in small concentrations is a proven non-toxic antibacterial agent, is an attractive way to manufacture implants with embedded antibacterial functionality. The possibility of achieving alloying in situ, during manufacturing, is a unique option of the LPBF technology. It provides unique opportunities to manufacture customized implant shapes and design new alloys. Nevertheless, optimal process parameters need to be established for the in situ alloyed materials to form dense parts with required mechanical properties. This research is dedicated to an investigation of Ti6Al4V (ELI-1 at % Cu material, manufactured by LPBF from a mixture of Ti6Al4V (ELI and pure Cu powders. The effect of process parameters on surface roughness, chemical composition and distribution of Cu was investigated. Chemical homogeneity was discussed in relation to differences in the viscosity and density of molten Cu and Ti6Al4V. Microstructure, mechanical properties, and fracture behavior of as-built 3D samples were analyzed and discussed. Pilot antibacterial functionalization testing of Ti6Al4V (ELI in situ alloyed with 1 at % Cu showed promising results and notable reduction in the growth of pure cultures of Escherichia coli and Staphylococcus aureus.

  19. Structure analysis of 3104 aluminium alloy applied to deep drawing

    Energy Technology Data Exchange (ETDEWEB)

    Klyszewski, A.; Lech-Grega, M.; Zelechowski, J.; Szymanski, W. [Light Metals Div., Skawina (Poland). Inst. of Non-Ferrous Metals

    2000-07-01

    Optical and electron microscopy observations and X-ray investigations of 3104 aluminium alloy ingots and bands after experimental heat treatment were carried out. The influence of ingots homogenisation temperature and parameters of material heat treatment after hot rolling on structure, texture and earing of band 0.3 mm thick was analysed. (orig.)

  20. Characteristics of aluminum alloy microplastic deformation in different structural states

    Energy Technology Data Exchange (ETDEWEB)

    Seregin, G.V.; Efimenko, L.L.; Leonov, M.V. [Novosibirsk Pedagogical Inst. (Russian Federation)

    1995-07-01

    The solution to the problem of improving the mechanical properties (including cyclic strength) of structural materials is largely dependent on our knowledge of the laws governing the development of microplastic deformations in them. The effect of heat and mechanical treatment on the elastoplastic properties and fatigue resistance of the commercial aluminum alloys AK4-1 and D16 is analyzed.

  1. Technical assessment of vanadium-base alloys for fusion reactor applications

    International Nuclear Information System (INIS)

    Gold, R.E.; Harrod, D.L.; Ammon, R.L.; Buckman, R.W. Jr.; Svedberg, R.C.

    1978-01-01

    A large data base has been compiled on vanadium-base alloys but the data base on any one alloy is quite limited. Great flexibility exists in the composition-microstructure-property relationship and this facilitates alloy optimization to meet diverse property requirements. Tensile properties and creep properties of existing alloys exceed likely requirements. Fatigue strength, including crack growth rate, is probably the most critical material property but no data exists for vanadium alloys. Swelling and irradiated ductility behavior look promising but require further evaluation. Vanadium alloy-liquid metal compatibility, particularly interstitial mass transfer, may be equally as critical as fatigue behavior; viability cannot be established with the existing data base. Fabricability must be given early consideration in alloys selection to guard against potentially serious problems in subsequent scale-up and production

  2. Qualification of Ti6Al4V ELI Alloy Produced by Laser Powder Bed Fusion for Biomedical Applications

    Science.gov (United States)

    Yadroitsev, I.; Krakhmalev, P.; Yadroitsava, I.; Du Plessis, A.

    2018-03-01

    Rectangular Ti6Al4V extralow interstitials (ELI) samples were manufactured by laser powder bed fusion (LPBF) in vertical and horizontal orientations relative to the build platform and subjected to various heat treatments. Detailed analyses of porosity, microstructure, residual stress, tensile properties, fatigue, and fracture surfaces were performed based on x-ray micro-computed tomography, scanning electron microscopy, and x-ray diffraction methods. The types of fracture and the tensile fracture mechanisms of the LPBF Ti6Al4V ELI alloy were also studied. Detailed analysis of the microstructure and the corresponding mechanical properties were compared against standard specifications for conventional Ti6Al4V alloy for use in surgical implant applications. Conclusions regarding the mechanical properties and heat treatment of LPBF Ti6Al4V ELI for biomedical applications are made.

  3. Numerical modelling of electromagnetic loads on fusion device structures

    International Nuclear Information System (INIS)

    Bettini, Paolo; Palumbo, Maurizio Furno; Specogna, Ruben

    2014-01-01

    In magnetic confinement fusion devices, during abnormal operations (disruptions) the plasma begins to move rapidly towards the vessel wall in a vertical displacement event (VDE), producing plasma current asymmetries, vessel eddy currents and open field line halo currents, each of which can exert potentially damaging forces upon the vessel and in-vessel components. This paper presents a methodology to estimate electromagnetic loads, on three-dimensional conductive structures surrounding the plasma, which arise from the interaction of halo-currents associated to VDEs with a magnetic field of the order of some Tesla needed for plasma confinement. Lorentz forces, calculated by complementary formulations, are used as constraining loads in a linear static structural analysis carried out on a detailed model of the mechanical structures of a representative machine

  4. Numerical modelling of electromagnetic loads on fusion device structures

    Science.gov (United States)

    Bettini, Paolo; Furno Palumbo, Maurizio; Specogna, Ruben

    2014-03-01

    In magnetic confinement fusion devices, during abnormal operations (disruptions) the plasma begins to move rapidly towards the vessel wall in a vertical displacement event (VDE), producing plasma current asymmetries, vessel eddy currents and open field line halo currents, each of which can exert potentially damaging forces upon the vessel and in-vessel components. This paper presents a methodology to estimate electromagnetic loads, on three-dimensional conductive structures surrounding the plasma, which arise from the interaction of halo-currents associated to VDEs with a magnetic field of the order of some Tesla needed for plasma confinement. Lorentz forces, calculated by complementary formulations, are used as constraining loads in a linear static structural analysis carried out on a detailed model of the mechanical structures of a representative machine.

  5. Neutron irradiation of V-Cr-Ti alloys in the BOR-60 fast reactor: Description of the fusion-1 experiment

    Energy Technology Data Exchange (ETDEWEB)

    Rowcliffe, A.F. [Oak Ridge National Laboratory, TN (United States); Tsai, H.C.; Smith, D.L. [Argonne National Lab., IL (United States)] [and others

    1997-08-01

    The FUSION-1 irradiation capsule was inserted in Row 5 of the BOR-60 fast reactor in June 1995. The capsule contains a collaborative RF/U.S. experiment to investigate the irradiation performance of V-Cr-Ti alloys in the temperature range 310 to 350{degrees}C. This report describes the capsule layout, specimen fabrication history, and the detailed test matrix for the U.S. specimens. A description of the operating history and neutronics will be presented in the next semiannual report.

  6. Structural and magnetic properties of nanocrystalline Fe–Co–Ni alloy processed by mechanical alloying

    International Nuclear Information System (INIS)

    Raanaei, Hossein; Eskandari, Hossein; Mohammad-Hosseini, Vahid

    2016-01-01

    In this present work, a nanostructured iron–cobalt–nickel alloy with Fe_5_0Co_3_0Ni_2_0 composition has been processed by mechanical alloying. The structural and magnetic properties have been investigated by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and vibrating sample magnetometer. It is shown that the crystallize size reaches to about 18.7 nm after 32 h milling time. A remarkable decrease in coercivity after 16 h milling time and also a continuous increase in remanent magnetization during the mechanical alloying process are observed. Heat treatment of the samples milled at 32 and 48 h demonstrates the crystalline constituent elements and also Fe_3O_4 crystalline phase. - Highlights: • This article focuses on mechanical alloying of Fe_5_0Co_3_0Ni_2_0 composition. • Structural and magnetic properties were investigated. • Saturation magnetization was increased sharply after 16 h of milling time. • The heat treatment revealed the signature of Fe_3O_4 as well as FeNi_3 and Co crystalline phases.

  7. Structural and magnetic properties of nanocrystalline Fe–Co–Ni alloy processed by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Raanaei, Hossein, E-mail: hraanaei@yahoo.com [Department of Physics, Persian Gulf University, Bushehr 75169 (Iran, Islamic Republic of); Eskandari, Hossein [Department of Mechanical Engineering, Persian Gulf University, Bushehr 75169 (Iran, Islamic Republic of); Mohammad-Hosseini, Vahid [Department of Physics, Persian Gulf University, Bushehr 75169 (Iran, Islamic Republic of)

    2016-01-15

    In this present work, a nanostructured iron–cobalt–nickel alloy with Fe{sub 50}Co{sub 30}Ni{sub 20} composition has been processed by mechanical alloying. The structural and magnetic properties have been investigated by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and vibrating sample magnetometer. It is shown that the crystallize size reaches to about 18.7 nm after 32 h milling time. A remarkable decrease in coercivity after 16 h milling time and also a continuous increase in remanent magnetization during the mechanical alloying process are observed. Heat treatment of the samples milled at 32 and 48 h demonstrates the crystalline constituent elements and also Fe{sub 3}O{sub 4} crystalline phase. - Highlights: • This article focuses on mechanical alloying of Fe{sub 50}Co{sub 30}Ni{sub 20} composition. • Structural and magnetic properties were investigated. • Saturation magnetization was increased sharply after 16 h of milling time. • The heat treatment revealed the signature of Fe{sub 3}O{sub 4} as well as FeNi{sub 3} and Co crystalline phases.

  8. Work hardening behavior study of structural alloys for cryogenic applications

    International Nuclear Information System (INIS)

    Chu, D.; Morris, J.W. Jr.

    1992-01-01

    Previous investigation on aluminum-lithium alloys have indicated different dependencies of the work hardening behavior on temperature. This variation in temperature dependence is attributed to differences in microstructure rather than composition. An understanding of the microstructural effect on the observed thermal dependency is important as it may allow the tailoring of deformation properties through mechanical processing. Work hardening analyses on other aluminum alloys and a number of structural steels have been performed to better elucidate the role played by microstructure in determining the work hardening behavior. In the paper correlations between the differences in mechanical behavior and the various microstructures observed are presented

  9. Simulation of Structural Transformations in Heating of Alloy Steel

    Science.gov (United States)

    Kurkin, A. S.; Makarov, E. L.; Kurkin, A. B.; Rubtsov, D. E.; Rubtsov, M. E.

    2017-07-01

    Amathematical model for computer simulation of structural transformations in an alloy steel under the conditions of the thermal cycle of multipass welding is presented. The austenitic transformation under the heating and the processes of decomposition of bainite and martensite under repeated heating are considered. Amethod for determining the necessary temperature-time parameters of the model from the chemical composition of the steel is described. Published data are processed and the results used to derive regression models of the temperature ranges and parameters of transformation kinetics of alloy steels. The method developed is used in computer simulation of the process of multipass welding of pipes by the finite-element method.

  10. Structural changes in heat resisting high nickel alloys during homogenization

    International Nuclear Information System (INIS)

    Kleshchev, A.S.; Korneeva, N.N.; Yurina, O.M.; Guzej, L.S.

    1981-01-01

    Effect of homogenization on the structure and technological plasticity of the KhN73MBTYu and KhN62BMKTYu alloys during treatment with pressure is investigated taking into account peculiarities if the phase composition. It is shown that homogenization of the KhN73MBTYu and KhN62BMKTYu alloys increases the technological plasticity. Homogenization efficiency is conditioned by the change of the grain boundaries and carbide morphology as well as by homogeneous distribution of the large γ'-phase [ru

  11. Metallurgical structures in a high uranium-silicon alloy

    International Nuclear Information System (INIS)

    Wyatt, B.S.; Berthiaume, L.C.; Conversi, J.L.

    1968-10-01

    The effects of fabrication and heat treatment variables on the structure of a uranium -- 3.96 wt% silicon alloy have been studied using optical microscopy, quantitative metallography and hardness determinations. It has been shown that an optimum temperature exists below the peritectoid temperature where the maximum amount of transformation to U 3 Si occurs in a given period of time. The time required to fully transform an as-cast alloy at this optimum temperature is affected by the size of the primary U 3 Si 2 dendrites. With a U 3 Si 2 particle size of <12 μm complete transformation can be achieved in four hours. (author)

  12. Alloying effect on the electronic structures of hydrogen storage compounds

    Energy Technology Data Exchange (ETDEWEB)

    Yukawa, H.; Moringa, M.; Takahashi, Y. [Nagoya Univ. (Japan). Dept. of Mater. Sci. and Eng.

    1997-05-20

    The electronic structures of hydrogenated LaNi{sub 5} containing various 3d transition elements were investigated by the DV-X{alpha} molecular orbital method. The hydrogen atom was found to form a strong chemical bond with the Ni rather than the La atoms. The alloying modified the chemical bond strengths between atoms in a small metal octahedron containing a hydrogen atom at the center, resulting in the change in the hydrogen absorption and desorption characteristics of LaNi{sub 5} with alloying. (orig.) 7 refs.

  13. Mossbauer analysis of the atomic and magnetic structure of alloys

    CERN Document Server

    Ovchinnikov, VV

    2007-01-01

    The monograph indicates the key problems that have to be solved for the further development of the Mössbauer methods for analysis of the nuclear and magnetic structure of alloys, and offer solution variants for some of these problems based on the generalised results of a wide range of theoretical and experimental investigations,including original work by the author of the book and his colleagues. Contents 1. Description of the nature of the Mössbauer effect 2. Interpretation of the ossbauer spectra of alloys 3.Electrical and magnetics hyperfine interactions of resonant nuclei in metals and

  14. Ductility behavior of irradiated path B alloys

    International Nuclear Information System (INIS)

    Yang, W.J.S.; Hamilton, M.L.

    1983-01-01

    The objective of this study was to assess the practicality of using five Path B alloys in their current form as structural materials in the Fusion First-Wall/Blanket by evaluating both their postirradiation ductility and the corresponding microstructures

  15. Prospect of Ti-Ni shape memory alloy applied in reactor structures

    International Nuclear Information System (INIS)

    Duan Yuangang

    1995-01-01

    Shape memory effect mechanism, physical property, composition, manufacturing process and application in mechanical structure of Ti-Ni shape memory alloy are introduced. Applications of Ti-Ni shape memory alloy in reactor structure are prospected and some necessary technical conditions of shape memory alloy applied in the reactor structure are put forward initially

  16. Magnetic susceptibility of transition metal alloys with a hcp structure

    International Nuclear Information System (INIS)

    Volkenshtejn, N.V.; Galoshina, Eh.V.; Gorina, N.B.; Korenovskij, N.L.; Polyakova, V.P.; Savitskij, E.M.

    1978-01-01

    The angular dependence of the magnetic susceptibility of single crystals of Ru-Nb, Re-W and Os-Re alloys is investigated in the region of the hexagonal closely packed structure. The spin susceptibility is estimated on the basis of available data on the electron specific heat. The principal values of the orbital component of the susceptibility are determined under the assumption of isotopy of the spin contribution to the susceptibility. In Ru-Nb alloys the magnitudes of the orbital contributions and the susceptibility anisotropy are found to increase; in Re-W the spin contribution is noticeably greater whereas the orbital susceptibility is smaller, as is the anistropy. In the Os-Re alloy the orbital contributions increase and the susceptibility anisotropy is constant. It is suggested that the addition of the second component changes the overlapping of the d-electron wave functions

  17. Shallow Boomerang-shaped Influenza Hemagglutinin G13A Mutant Structure Promotes Leaky Membrane Fusion*

    Science.gov (United States)

    Lai, Alex L.; Tamm, Lukas K.

    2010-01-01

    Our previous studies showed that an angled boomerang-shaped structure of the influenza hemagglutinin (HA) fusion domain is critical for virus entry into host cells by membrane fusion. Because the acute angle of ∼105° of the wild-type fusion domain promotes efficient non-leaky membrane fusion, we asked whether different angles would still support fusion and thus facilitate virus entry. Here, we show that the G13A fusion domain mutant produces a new leaky fusion phenotype. The mutant fusion domain structure was solved by NMR spectroscopy in a lipid environment at fusion pH. The mutant adopted a boomerang structure similar to that of wild type but with a shallower kink angle of ∼150°. G13A perturbed the structure of model membranes to a lesser degree than wild type but to a greater degree than non-fusogenic fusion domain mutants. The strength of G13A binding to lipid bilayers was also intermediate between that of wild type and non-fusogenic mutants. These membrane interactions provide a clear link between structure and function of influenza fusion domains: an acute angle is required to promote clean non-leaky fusion suitable for virus entry presumably by interaction of the fusion domain with the transmembrane domain deep in the lipid bilayer. A shallower angle perturbs the bilayer of the target membrane so that it becomes leaky and unable to form a clean fusion pore. Mutants with no fixed boomerang angle interacted with bilayers weakly and did not promote any fusion or membrane perturbation. PMID:20826788

  18. Structural transformations in quenched Fe-Ga alloys

    International Nuclear Information System (INIS)

    Lograsso, T.A.; Ross, A.R.; Schlagel, D.L.; Clark, A.E.; Wun-Fogle, M.

    2003-01-01

    It has been speculated that the large increase in magnetostriction in Fe-Ga alloys results from local short-range ordering of the Ga atoms along specific crystallographic directions in the disordered Fe structure. The structural transitions associated with different cooling rates from the high temperature disordered state were investigated with X-ray diffraction of oriented single crystals of Fe-19 at% Ga. Results are presented for long-range ordering during slow cooling and indirect evidence of local short-range ordering of Ga atoms in the disordered state when the alloys are quenched is also presented. In the latter case, the short-range ordering of Ga atoms leads to a tetragonal distortion of the lattice. The dependence of the magnetostrictive response of Fe-Ga alloys on thermal history has been found to be directly related to these structural transformations in Fe-19 at% Ga alloys and experimental support for the proposed magnetostriction model based on Ga-Ga pairing along [100] crystallographic directions is presented

  19. Mechanical properties and structure of magnesium alloy AS31

    Directory of Open Access Journals (Sweden)

    A. Hanus

    2008-07-01

    Full Text Available Contemporary materials should possess high mechanical properties, physical and chemical, as well as technological ones, to ensure long and reliable use. The non-ferrous metals alloys used nowadays, including the magnesium alloys, meet the above-mentioned requirements and expectations regarding the contemporary materials.Magnesium alloys are primarily used in aeronautical and automobile industry in wide variety of structural characteristics because of their favorable combination of tensile strength (160 to 365 MPa, elastic modulus (45 GPa, and low density (1 740 kg/m3, which is two-thirds that of aluminum. Magnesium alloys have high strength-to-weight ratio (tensile strength/density, comparable to those of other structural metals. [1-6]Knowledge of the relaxation properties of metal materials at high temperatures is necessary for the verification of susceptibility of castings to the creation of defects during the production process. Temperature limits of materials where highest tension values are generated may be detected with tensile tests under high temperatures. The generated tensions in the casting are a cause of the creation and development of defects. At acoustic emission (hereinafter called the "AE" use, tensile tests at high temperatures may, among other things, be used for analysis of the AE signal sources and set, in more detail, the temperature limit of elastic-plastic deformations existence in the material under examination. The results of the temperature drop where tension at casting cooling is generated or its release at heating are basic data for controlled cooling mode (and temperature of casting knocking out of the form as well as necessary for the thermal mode for the casting tension reduction. [7-9]Knowledge of elastic-plastic properties at elevated temperatures is often important for complex evaluation of magnesium alloys. Objective of the work was focused on determination of changes of elastic-plastic properties of magnesium

  20. Structural performance of a graphite blanket in fusion reactors

    International Nuclear Information System (INIS)

    Wolfer, W.G.; Watson, R.D.

    1978-01-01

    Irradiation of graphite in a fusion reactor causes dimensional changes, enhanced creep, and changes in elastic properties and fracture strength. Temperature and flux gradients through the graphite blanket structure produce differential distortions and stress gradients. An inelastic stress analysis procedure is described which treats these variations of the graphite properties in a consistent manner as dictated by physical models for the radiation effects. Furthermore, the procedure follows the evolution of the stress and fracture strength distributions during the reactor operation as well as for possible shutdowns at any time. The lifetime of the graphite structure can be determined based on the failure criterion that the stress at any location exceeds one-half of the fracture strength. This procedure is applied to the most critical component of the blanket module in the SOLASE design

  1. Strength, ductility, and ductile-brittle transition temperature for MFR [magnetic fusion reactor] candidate vanadium alloys

    International Nuclear Information System (INIS)

    Loomis, B.A.; Lee, R.H.; Smith, D.L.; Peterson, J.R.

    1987-09-01

    The dependence of the yield strength, tensile strength, elongation, and reduction in area on temperature for the V-15Ti-7.5Cr, V-20Ti, V-15Cr-5Ti, V-12Cr-5Ti, V-10Cr-5Ti, and V-3Ti-1Si alloys was determined from tensile tests at temperatures ranging from 25 to 700 0 C. The strength of the alloys increased with an increase of the combined Cr and Ti concentration. The total elongation for the alloys ranged between 20% and 38%. The reduction in area ranged from 30% to 90%. The DBTT, which was determined from the temperature dependence of the reduction in area, was less than 25 0 C for the V-15Ti-7.5Cr, V-20Ti, and V-3Ti-1Si alloys. The DBTT for the V-10Cr-5Ti, V-12Cr-5Ti, and V-15Cr-5Ti alloys was also less than 25 0 C if these alloys were annealed to reduce the hydrogen concentration prior to the tensile test. If these latter alloys were not annealed prior to the tensile test, the DBTT ranged from 40 0 C to 90 0 C and the DBTT increased with an increase of the Cr concentration. A Cr/Ti concentration ratio of 0 to 0.5 in these alloys was found to cause the alloys to be less susceptible to hydrogen embrittlement. 14 refs., 4 figs., 3 tabs

  2. Technical assessment of niobium alloys data base for fusion reactor applications

    Energy Technology Data Exchange (ETDEWEB)

    Pionke, L J; Davis, J W

    1979-08-01

    Refractory metals are one class of material to be developed in the Alloy Development For Irradiation Performance (ADIP) program recently initiated. A principal purpose of the assessment reported herein is to establish the existing data base for niobium alloys in order to help guide the work to be performed in the ADIP program. Major ADIP decisions include alloy selection/modification and irradiated/unirradiated material testing. This Assessment addressed the topics of: (1) niobium alloy development history and niobium metallurgy, (2) unirradiated mechanical properties, (3) irradiated properties, (4) corrosion, and (5) environmental effects.

  3. Characterization of HCoV-229E fusion core: Implications for structure basis of coronavirus membrane fusion

    International Nuclear Information System (INIS)

    Liu Cheng; Feng Youjun; Gao Feng; Zhang Qiangmin; Wang Ming

    2006-01-01

    Human coronavirus 229E (HCoV-229E), a member of group I coronaviruses, has been identified as one of the major viral agents causing respiratory tract diseases in humans for nearly 40 years. However, the detailed molecular mechanism of the membrane fusion mediated by the spike (S) protein of HCoV-229E remains elusive. Here, we report, for the first time, a rationally designed fusion core of HCoV-229E (HR1-SGGRGG-HR2), which was in vitro produced in GST prokaryotic expression system. Multiple lines of experimental data including gel-filtration, chemical cross-linking, and circular diagram (CD) demonstrated that the HCoV-229E fusion core possesses the typical properties of the trimer of coiled-coil heterodimer (six α-helix bundle). 3D structure modeling presents its most-likely structure, similar to those of coronaviruses that have been well-documented. Collectively, HCoV-229E S protein belongs to the type I fusion protein, which is characterized by the existence of two heptad-repeat regions (HR1 and HR2), furthermore, the available knowledge concerning HCoV-229E fusion core may make it possible to design small molecule or polypeptide drugs targeting the membrane fusion, a crucial step of HCoV-229E infection

  4. Structural and transport properties of Sn-Mg alloys

    International Nuclear Information System (INIS)

    Meydaneri, F.; Saatci, E.; Oezdemir, M.; Ari, M.; Durmus, S.

    2010-01-01

    The structural and temperature dependence transport of Sn-Mg alloys have been investigated for five different samples (Pure Sn, Sn-1.0 wt % Mg , Sn-2.0 wt % Mg , Sn-6.0 wt.% Mg and Pure Mg). Scanning Electron Microscopy (SEM), x-ray diffraction (XRD) and Energy Dispersive x-ray Analysis (EDX) measurements were carried out in order to clarify the structural properties of the samples. It has been found that, the samples have tetragonal crystal symmetry except the pure Mg which has hexagonal crystal symmetry. The cell parameters decrease slightly with addition of Mg element. The SEM micrographs of the samples show that, the samples have smooth surfaces with clear grain boundary. There is no crack, porosity or defects on the surfaces. The electrical resistivity of the samples increases almost linearly with the increasing temperature, which were measured by four-point probe technique. The thermal conductivity values are in between 0.60-1.00 W/Km, which are decrease slightly with temperature and increase with composition of Mg. The thermal conductivity values of the alloys are in between the values of the pure samples. Thermal conductivity results of the alloys have been compared with available other studies and a good agreement has been seen between the results. In addition, the temperature coefficients of electrical resistivity and thermal conductivity have been determined, which are independent with the compositions of alloying elements

  5. Characterization and structure of precipitates in 6xxx Aluminium Alloys

    International Nuclear Information System (INIS)

    Holmestad, Randi; Bjørge, Ruben; Ehlers, Flemming J H; Torsæter, Malin; Marioara, Calin D; Andersen, Sigmund J

    2012-01-01

    Solute atom nanoscale precipitates are responsible for the favourable mechanical properties of heat treatable aluminium alloys such as Al-Mg-Si (6xxx). The shape, structure and strengthening properties of age-hardening precipitates depend on alloy composition and thermo-mechanical history. We seek an improved understanding of the physics related to nucleation and precipitation on the atomistic level in these alloys. Once these mechanisms are sufficiently well described and understood, the hope is that 'alloy design' simulations can assist tailoring of materials with desired properties. In pure Al-Mg-Si we have determined the structure of nearly all the known metastable precipitate phases, by combining advanced TEM techniques (such as high resolution TEM and nano-beam diffraction) with atom probe tomography and density functional theory. We are now studying effects of additions /substitutions of Cu, Ag and/or Ge that promote formation of more disordered precipitates, employing aberration corrected high angle annular dark field scanning TEM. We find that all metastable precipitates contain variations of a widely spaced 'Si/Ge network'. In spite of disorder or defects, this network is surprisingly well ordered, with hexagonal projected sub-cell dimensions a = b ≅ 0.4 nm and c (along the fully coherent precipitate main growth direction) equal to 0.405 nm or a multiple of it.

  6. Precipitation sensitivity to alloy composition in Fe-Cr-Mn austenitic steels developed for reduced activation for fusion application

    International Nuclear Information System (INIS)

    Maziasz, P.J.; Klueh, R.L.

    1988-01-01

    Special austenitic steels are being designed in which alloying elements like Mo, Nb, and Ni are replaced with Mn, W, V, Ti, and/or Ta to reduce the long-term radioactivity induced by fusion reactor irradiation. However, the new steels still need to have properties otherwise similar to commercial steels like type 316. Precipitation strongly affects strength and radiation-resistance in austenitic steels during irradiation at 400--600/degree/C, and precipitation is also usually quite sensitive to alloy composition. The initial stage of development was to define a base Fe-Cr-Mn-C composition that formed stable austenite after annealing and cold-working, and resisted recovery or excessive formation of coarse carbide and intermetallic phases during elevated temperature annealing. These studies produced a Fe-12Cr-20Mn-0.25C base alloy. The next stage was to add the minor alloying elements W, Ti, V, P, and B for more strength and radiation-resistance. One of the goals was to produce fine MC precipitation behavior similar to the Ti-modified Fe-Cr-Ni prime candidate alloy (PCA). Additions of Ti+V+P+B produced fine MC precipitation along network dislocations and recovery/recrystallization resistance in 20% cold worked material aged at 800/degree/C for 166h, whereas W, Ti, W+Ti, or Ti+P+B additions did not. Addition of W+Ti+V+P+B also produced fine MC, but caused some σ phase formation and more recrystallization as well. 29 refs., 14 figs., 9 tabs

  7. Nanocrystalline Fe-Pt alloys. Phase transformations, structure and magnetism

    Energy Technology Data Exchange (ETDEWEB)

    Lyubina, J.V.

    2006-12-21

    This work has been devoted to the study of phase transformations involving chemical ordering and magnetic properties evolution in bulk Fe-Pt alloys composed of nanometersized grains. Nanocrystalline Fe{sub 100-x}Pt{sub x} (x=40-60) alloys have been prepared by mechanical ball milling of elemental Fe and Pt powders at liquid nitrogen temperature. The as-milled Fe-Pt alloys consist of {proportional_to} 100 {mu}m sized particles constituted by randomly oriented grains having an average size in the range of 10-40 nm. Depending on the milling time, three major microstructure types have been obtained: samples with a multilayer-type structure of Fe and Pt with a thickness of 20-300 nm and a very thin (several nanometers) A1 layer at their interfaces (2 h milled), an intermediate structure, consisting of finer lamellae of Fe and Pt (below approximately 100 nm) with the A1 layer thickness reaching several tens of nanometers (4 h milled) and alloys containing a homogeneous A1 phase (7 h milled). Subsequent heat treatment at elevated temperatures is required for the formation of the L1{sub 0} FePt phase. The ordering develops via so-called combined solid state reactions. It is accompanied by grain growth and thermally assisted removal of defects introduced by milling and proceeds rapidly at moderate temperatures by nucleation and growth of the ordered phases with a high degree of the long-range order. In a two-particle interaction model elaborated in the present work, the existence of hysteresis in recoil loops has been shown to arise from insufficient coupling between the low- and the high-anisotropy particles. The model reveals the main features of magnetisation reversal processes observed experimentally in exchange-coupled systems. Neutron diffraction has been used for the investigation of the magnetic structure of ordered and partially ordered nanocrystalline Fe-Pt alloys. (orig.)

  8. Fusion and characterization of an alloy Cu-Zn-Al-Ni of nuclear interest

    International Nuclear Information System (INIS)

    Santana M, J.S.

    2003-01-01

    The present work is the result of the study of a non ferrous quatenary alloy of Cu-Zn-Al-Ni (Foundry 3), it was chosen of a series of alloys to obtain so much information of its microstructural properties like mechanical, evaluating them and comparing them with the previously obtained ternary alloys of Cu-AI-Ni (Foundry 1) and Cu-Zn-AI (Foundry 2) identified as alloys of memory effect and superalloys. These were carried out starting from the foundry of their pure elements of Cu, Zn, Al, Ni. When physically having the ingot of each alloy, different techniques were used for their characterization. The used techniques were through the metallographic analysis, by scanning electron microscopy (SEM), X-ray dispersive energy spectroscopy (EDS), X-ray diffraction (XRD), mechanical essays and Rockwell hardness. The non ferrous quaternary alloy Cu-Zn-AI-Ni by means of the metallographic analysis didn't show significant differences in their three sections (superficial, longitudinal and transverse) since result an homogeneous alloy at the same that the both ternaries. The grain size of the quaternary alloy is the finest while the ternary alloy of Cu-AI-Ni is the one that obtained the biggest grain size. Through MEB together with the analysis by EDS and the mapping of the elements that constitute each alloy, show that the three foundries were alloyed, moreover the presence of aggregates was also observed in the Foundries 2 and 3. These results by means of the analysis of XRD corroborate that these alloys have more of two elements. Relating the microstructural properties with those mechanical show us that as minor was the grain size, better they were his mechanical properties, in this case that of the quaternary alloy. With regard to the test of Rockwell hardness the Foundry 1 were the softest with the temper treatment, while that the Foundries 2 and 3 were the hardest with this same treatment, being still harder the Foundry 2 but with very little difference, for what great

  9. Effect of heat treatment and hot isostatic pressing on the microstructure and mechanical properties of Inconel 625 alloy processed by laser powder bed fusion

    Energy Technology Data Exchange (ETDEWEB)

    Kreitcberg, Alena, E-mail: alena.kreitcberg.1@ens.etsmtl.ca [École de technologie supérieure, 110 Notre-Dame Street West, Montreal, Quebec H3C 1K3 Canada (Canada); Brailovski, Vladimir, E-mail: vladimir.brailovski@etsmtl.ca [École de technologie supérieure, 110 Notre-Dame Street West, Montreal, Quebec H3C 1K3 Canada (Canada); Turenne, Sylvain, E-mail: sylvain.turenne@polymtl.ca [École Polytechnique de Montréal, 2900 boul. Édouard-Montpetit, Montreal, Quebec H3T 1J4 Canada (Canada)

    2017-03-24

    The effect of different heat treatments and hot isostatic pressing on the microstructure and mechanical properties of laser powder bed fusion IN625 alloy was studied. The heat treatments were: stress relief annealing, recrystallization annealing and low-temperature solution treatment. The resulting microstructure and crystallographic textures were studied using optical and scanning electron microscopy. The mechanical properties of the as-built and post-treated IN625 alloy were obtained after tensile testing at room temperature and at 760 °C (1400 °F), and compared to those of an annealed wrought alloy of the same composition.

  10. Dilogarithm identities, fusion rules and structure constants of CFTs

    International Nuclear Information System (INIS)

    Terhoeven, M.

    1993-07-01

    Recently dilogarithm identities have made their appearance in the physics literature. This identities seem to allow to calculate structure constants like, in particular, the effective central charge of certain conformal field theories from their fusion rules. In Nahm, Recknagel, Terhoeven (1992) a proof of identities of this type was given by considering the asymptotics of character functions in the so-called Rogers-Ramanujan sum form and comparing with the asymptotics predicted by modular covariance. Refining the argument, we obtain the general connection of quantum dimensions of certain conformal field theories to the arguments of the dilogarithm function in the identities in question and an infinite set of consistency conditions on the parameters of Rogers-Ramanujan type partitions for them to be modular covariant. (orig.)

  11. Effects of alloying and transmutation impurities on stability and mobility of helium in tungsten under a fusion environment

    International Nuclear Information System (INIS)

    Wu Xuebang; Kong Xiangshan; You Yuwei; Liu, C.S.; Fang, Q.F.; Chen Junling; Luo, G.-N.; Wang Zhiguang

    2013-01-01

    The behaviour of helium in metals is particularly significant in fusion research due to the He-induced degradation of materials. A small amount of impurities introduced either by intentional alloying or by transmutation reactions, will interact with He and lead the microstructure and mechanical properties of materials to change. In this paper, we present the results of first-principles calculations on the interactions of He with impurities and He diffusion around them in tungsten (W), including the interstitials Be, C, N, O, and substitutional solutes Re, Ta, Tc, Nb, V, Os, Ti, Si, Zr, Y and Sc. We find that the trapping radii of interstitial atoms on He are much larger than those of substitutional solutes. The binding energies between the substitutional impurities and He increase linearly with the relative charge densities at the He occupation site, indicating that He atoms easily aggregate at the low charge density site. The sequence of diffusion energy barriers of He around the possible alloying elements is Ti > V > Os > Ta > Re. The present results suggest that Ta might be chosen as a relatively suitable alloying element compared with other possible ones. (paper)

  12. A Novel 3D Printer to Support Additive Manufacturing of Gradient Metal Alloy Structures, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Gradient metal alloy structures possess multi-functional properties that conventional monolithic metal counterparts do not have. Such structures can potentially...

  13. A Novel 3D Printer to Support Additive Manufacturing of Gradient Metal Alloy Structures, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Gradient metal alloy structures possess multi-functional properties that conventional monolithic metal counterparts do not have. Such structures can potentially...

  14. Critical survey of the neutron-induced creep behaviour of steel alloys for the fusion reactor materials programme

    International Nuclear Information System (INIS)

    Hausen, H.

    1985-01-01

    The differences between the irradiation environment of a fission reactor and that of a fusion reactor are respectively described in relation to the radiation damage found and expected in the two types of nuclear reactor. It is shown that the microstructure developing for instance in stainless steel alloys is almost invariant to whether the production rate of helium is high or low. The finding is valid up to neutron doses corresponding to about 60 dpa. For this reason, irradiation creep data obtained in fission reactors may be used, with caution, for predicting creep behaviour in fusion reactors.It was further recognized that irradiation creep performed with high energy particles from an accelerator, yields results which are comparable to those obtained in fission reactors. For this reason, simulation creep experiments are found to be valuable for the development of irradiation creep resistant materials using, for example, high energy electrons or protons. Such kind of experiments are performed in many laboratories. For irradiation doses larger than 60 dpa, predictions with respect to creep rates in fission and fusion reactors are difficult. In end-of-life tests, which concern swelling, ductility, tensile properties, rupture, fatigue and embrittlement, the presence of helium, due to its production rate being much higher in most materials exposed to 14 MeV neutrons than to fission neutrons, may be of great importance

  15. Study of the evolution of irradiation induced defects in FeCrx model alloys for fusion applications by means of in-situ resistivity techniques

    International Nuclear Information System (INIS)

    Gómez-Ferrer Ferrán, B.

    2014-01-01

    Reduced activation ferritic/martensitic steels are candidate structural materials for future fusion reactors. These steels can, to a first approximation, be modelled by considering the behavior of binary Fe-Cr alloys. It has been shown that a significant amount of Cr, in the range of 6-14at%, is necessary to provide good mechanical properties of radiation and corrosion resistance. The microstructure evolution induced by neutron irradiation is known to depend on the Cr content. Current knowledge of the role of Cr in the effects of neutron radiation is therefore essential, but still incomplete. The current objective is to extend the experimental study of the point-defect interaction and kinetics in concentrated alloys. This would allow increasing a reliable database of experimental results for validation of computational simulations in order to consolidate the development of models. Thus, to this end, a suitable experimental set-up has been designed and built and subsequently Resistivity Recovery experiments have been run in Fe1-x-Crx (x = 0, 0.05, 0.10, 0.14)...(Author)

  16. Solidified structure of Al-Pb-Cu alloys

    International Nuclear Information System (INIS)

    Ikeda, Tetsuyuki; Nishi, Seiki; Kumeuchi, Hiroyuki; Tatsuta, Yoshinori.

    1986-01-01

    Al-Pb-Cu alloys were cast into bars or plates in different two metal mold casting processes in order to suppress gravity segregation of Pb and to achieve homogeneous dispersion of Pb phase in the alloys. Solidified structures were analyzed by a video-pattern-analyzer. Plate castings 15 to 20 mm in thickness of Al-Pb-1 % Cu alloy containing Pb up to 5 % in which Pb phase particles up to 10 μm disperse are achieved through water cooled metal mold casting. The plates up to 5 mm in thickness containing Pb as much as 8 to 10 % cast in this process have dispersed Pb particles up to 5 μm in diameter in the surface layer. Al-8 % Pb-1 % Cu alloy bars 40 mm in diameter and 180 mm in height in which gravity segregation of Pb is prevented can be cast by movable and water sprayed metal mold casting at casting temperature 920 deg C and mold moving speed 1.0 mm/s. Pb phase particles 10 μm in mean size are dispersed in the bars. (author)

  17. Structural models for amorphous transition metal binary alloys

    International Nuclear Information System (INIS)

    Ching, W.Y.; Lin, C.C.

    1976-01-01

    A dense random packing of 445 hard spheres with two different diameters in a concentration ratio of 3 : 1 was hand-built to simulate the structure of amorphous transition metal-metalloid alloys. By introducing appropriate pair potentials of the Lennard-Jones type, the structure is dynamically relaxed by minimizing the total energy. The radial distribution functions (RDF) for amorphous Fe 0 . 75 P 0 . 25 , Ni 0 . 75 P 0 . 25 , Co 0 . 75 P 0 . 25 are obtained and compared with the experimental data. The calculated RDF's are resolved into their partial components. The results indicate that such dynamically constructed models are capable of accounting for some subtle features in the RDF of amorphous transition metal-metalloid alloys

  18. Electron microscope investigation into dislocation structure of cast aluminium alloys

    International Nuclear Information System (INIS)

    Zolotorevskij, V.S.; Orelkina, T.A.; Istomin-Kastrovskij, V.V.

    1978-01-01

    By applying the diffraction electron microscopy method, the general specific features of the disclocation structure of cast binary alloys of aluminium with different additions were established. It is shown that in most alloys, when they undergo cooling in the process of crystallization at the rate of about 850 deg/min, the cellular dislocation structure is formed. It is shown that in all the alloys studied, the total density of dislocations of one order is about-10 9 cm -2 , which exceeds by 1 to 2 orders of magnitude the value which follows from the Tiller theory of concentration stresses. It has been experimentally established that the contribution of shrinkage and thermal stresses to the formation of a dislocation structure is rather insignificant; yet the dislocation density values calculated according to the size of dendritic cells and the medium angles of their disorientation are close to those determined by the electron-microscopic method. This is the basis for making a supposition that the greater part of the dislocations in castings are formed as a result of comparing dendritic branches with one another, which are disoriented in respect to each other

  19. Fe-15Ni-13Cr austenitic stainless steels for fission and fusion reactor applications. I. Effects of minor alloying elements on precipitate phases in melt products and implication in alloy fabrication

    International Nuclear Information System (INIS)

    Lee, E.H.; Mansur, L.K.

    2000-01-01

    In an effort to develop alloys for fission and fusion reactor applications, 28Fe-15Ni-13Cr base alloys were fabricated by adding various combinations of the minor alloying elements, Mo, Ti, C, Si, P, Nb, and B. The results showed that a significant fraction of undesirable residual oxygen was removed as oxides when Ti, C, and Si were added. Accordingly, the concentrations of the latter three essential alloying elements were reduced also. Among these elements, Ti was the strongest oxide former, but the largest oxygen removal (over 80%) was observed when carbon was added alone without Ti, since gaseous CO boiled off during melting. This paper recommends an alloy melting procedure to mitigate solute losses while reducing the undesirable residual oxygen. In this work, 14 different types of precipitate phases were identified. Compositions of precipitate phases and their crystallographic data are documented. Finally, stability of precipitate phases was examined in view of Gibbs free energy of formation

  20. The Static and Fatigue Behavior of AlSiMg Alloy Plain, Notched, and Diamond Lattice Specimens Fabricated by Laser Powder Bed Fusion

    Directory of Open Access Journals (Sweden)

    Hugo Soul

    2018-04-01

    Full Text Available The fabrication of engineered lattice structures has recently gained momentum due to the development of novel additive manufacturing techniques. Interest in lattice structures resides not only in the possibility of obtaining efficient lightweight materials, but also in the functionality of pre-designed architectured structures for specific applications, such as biomimetic implants, chemical catalyzers, and heat transfer devices. The mechanical behaviour of lattice structures depends not only the composition of the base material, but also on the type and size of the unit cells, as well as on the material microstructure resulting from a specific fabrication procedure. The present work focuses on the static and fatigue behavior of diamond cell lattice structures fabricated from an AlSiMg alloy by laser powder bed fusion technology. In particular, the specimens were fabricated with three different orientations of lattice cells—[001], [011], [111]—and subjected to static tensile testing and force-controlled pull–pull fatigue testing up to 1 × 107 cycles. In parallel, the mechanical behavior of dense tensile plain and notched specimens was also studied and compared to that of their lattice counterparts. Results showed a significant effect of the cell orientation on the fatigue lives: specimens oriented at [001] were ~30% more fatigue-resistant than specimens oriented at [011] and [111].

  1. Microstructure and stress corrosion cracking of the fusion boundary region in an alloy 182-A533B low alloy steel dissimilar weld joint

    International Nuclear Information System (INIS)

    Hou, Juan; Peng, Qunjia; Takeda, Yoichi; Kuniya, Jiro; Shoji, Tetsuo

    2010-01-01

    Research highlights: → High-angle misorientation at FB, type-II and type-I boundaries. → Highest residual strain and hardness in the zone between FB and type-II boundary. → Type-II and type-I boundaries had lower resistance to SCC growth than the FB. → Crack growth blunted by pitting at the FB. → Reactivation of crack growth from the pitting by oxidation along the grain boundary. - Abstract: Stress corrosion cracking (SCC) in the fusion boundary (FB) region of an Alloy 182-A533B low alloy steel (LAS) dissimilar weld joint in high temperature water doped with sulfate was studied following a microstructure characterization of the FB region. The microstructure characterization suggested the type-II and type-I boundaries in the dilution zone (DZ) adjacent to the FB had lower resistance to SCC growth than the FB. Crack propagating perpendicular to the FB in the DZ was observed to be blunted by pitting at the FB, followed by the reactivation from the pitting by localized oxidation along the grain boundary in LAS.

  2. Structural Transition and Antibody Binding of EBOV GP and ZIKV E Proteins from Pre-Fusion to Fusion-Initiation State

    Directory of Open Access Journals (Sweden)

    Anna Lappala

    2018-05-01

    Full Text Available Membrane fusion proteins are responsible for viral entry into host cells—a crucial first step in viral infection. These proteins undergo large conformational changes from pre-fusion to fusion-initiation structures, and, despite differences in viral genomes and disease etiology, many fusion proteins are arranged as trimers. Structural information for both pre-fusion and fusion-initiation states is critical for understanding virus neutralization by the host immune system. In the case of Ebola virus glycoprotein (EBOV GP and Zika virus envelope protein (ZIKV E, pre-fusion state structures have been identified experimentally, but only partial structures of fusion-initiation states have been described. While the fusion-initiation structure is in an energetically unfavorable state that is difficult to solve experimentally, the existing structural information combined with computational approaches enabled the modeling of fusion-initiation state structures of both proteins. These structural models provide an improved understanding of four different neutralizing antibodies in the prevention of viral host entry.

  3. Microstructure evolution in the fusion zone of laser-welded Mg–Gd–Y–Zr alloy during solution and aging treatment

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lyuyuan [Shanghai Key Laboratory of Materials Laser Processing and Modification, Shanghai Jiao Tong University, Shanghai 200240 (China); Huang, Jian, E-mail: jhuang@sjtu.edu.cn [Shanghai Key Laboratory of Materials Laser Processing and Modification, Shanghai Jiao Tong University, Shanghai 200240 (China); Dong, Jie [National Engineering Research Center of Light Alloys Net Forming, Shanghai Jiao Tong University, Shanghai 200240 (China); Feng, Kai [Shanghai Key Laboratory of Materials Laser Processing and Modification, Shanghai Jiao Tong University, Shanghai 200240 (China); Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Wu, Yixiong [Shanghai Key Laboratory of Materials Laser Processing and Modification, Shanghai Jiao Tong University, Shanghai 200240 (China); Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

    2016-08-15

    The microstructure evolution in the fusion zone of laser-welded Mg-Gd-Y-Zr alloy during solution and aging treatment is investigated. The morphology of the Mg{sub 24}(Gd,Y){sub 5} in the divorced eutectic at the grain boundary transforms from a continuous network to disconnected and fragmentized islands and then to spheroidal particles before complete dissolution during the solution treatment at 430 °C. During the subsequent aging treatment at 225 °C, the precipitation sequence in the fusion zone follows the order of supersaturated solid solution (SSSS) → βʺ(D0{sub 19}) → βʹ(cbco) → β{sub 1}(fcc) → β(fcc). High-density precipitates are present at the original grain boundaries of the fusion zone from the welded structure but there are less precipitates in the interior of the original grains. The grain growth during the solution treatment at 430 °C comprises the slowly increasing stage, rapidly increasing stage, and stable stage. The network-distributed Mg{sub 24}(Gd,Y){sub 5} impedes migration of the grain boundaries, restricts grain growth in the first slowly increasing stage, and segregation of zirconium near the grain boundaries also affects migration of the grain boundaries. - Highlights: •Different quantities of precipitates are present at different location of grain. •The network-distributed Mg{sub 24}(Gd,Y){sub 5} restricts grain growth. •Segregation of Zr affects migration of grain boundaries.

  4. Determination of the enthalpy of fusion and thermal diffusivity for ternary Cu_6_0_−_xSn_xSb_4_0 alloys

    International Nuclear Information System (INIS)

    Zhai, W.; Zhou, K.; Hu, L.; Wei, B.

    2016-01-01

    Highlights: • The increasing Sn content reduces the liquidus temperature. • High Sn content results in lower enthalpy of fusion by polynomial functions. • The thermal diffusivity drops from the solid toward the semi-solid state. • Undercoolability of alloys with primary Cu_2Sb phase is stronger than others. - Abstract: The liquidus and solidus temperatures, enthalpy of fusion, and the temperature dependence of thermal diffusivity for ternary Cu_6_0_−_xSn_xSb_4_0 alloys were systematically measured by DSC and laser flash methods. It is found that both the liquidus temperature and the enthalpy of fusion decrease with the rise of Sn content, and their relationships with alloy composition were established by polynomial functions. The thermal diffusivity usually drops from the solid toward the semi-solid state. The undercoolability of those liquid Cu_6_0_−_xSn_xSb_4_0 alloys with primary Cu_2Sb solid phase is stronger than the others with primary β(SnSb) intermetallic compound, and the increase of cooling rate facilitates further undercooling. Microstructural observation indicates that both of the primary Cu_2Sb and β(SnSb) intermetallic compounds in ternary Cu_6_0_−_xSn_xSb_4_0 alloys grow in faceted mode, and develop into coarse flakes and polygonal blocks.

  5. Smart tungsten alloys as a material for the first wall of a future fusion power plant

    Science.gov (United States)

    Litnovsky, A.; Wegener, T.; Klein, F.; Linsmeier, Ch.; Rasinski, M.; Kreter, A.; Unterberg, B.; Coenen, J. W.; Du, H.; Mayer, J.; Garcia-Rosales, C.; Calvo, A.; Ordas, N.

    2017-06-01

    Tungsten is currently deemed as a promising plasma-facing material (PFM) for the future power plant DEMO. In the case of an accident, air can get into contact with PFMs during the air ingress. The temperature of PFMs can rise up to 1200 °C due to nuclear decay heat in the case of damaged coolant supply. Heated neutron-activated tungsten forms a volatile radioactive oxide which can be mobilized into the atmosphere. New self-passivating ‘smart’ alloys can adjust their properties to the environment. During plasma operation the preferential sputtering of lighter alloying elements will leave an almost pure tungsten surface facing the plasma. During an accident the alloying elements in the bulk are forming oxides thus protecting tungsten from mobilization. Good plasma performance and the suppression of oxidation are required for smart alloys. Bulk tungsten (W)-chroimum (Cr)-titanium (Ti) alloys were exposed together with pure tungsten (W) samples to the steady-state deuterium plasma under identical conditions in the linear plasma device PSI 2. The temperature of the samples was ~576 °C-715 °C, the energy of impinging ions was 210 eV matching well the conditions expected at the first wall of DEMO. Weight loss measurements demonstrated similar mass decrease of smart alloys and pure tungsten samples. The oxidation of exposed samples has proven no effect of plasma exposure on the oxidation resistance. The W-Cr-Ti alloy demonstrated advantageous 3-fold lower mass gain due to oxidation than that of pure tungsten. New yttrium (Y)-containing thin film systems are demonstrating superior performance in comparison to that of W-Cr-Ti systems and of pure W. The oxidation rate constant of W-Cr-Y thin film is 105 times less than that of pure tungsten. However, the detected reactivity of the bulk smart alloy in humid atmosphere is calling for a further improvement.

  6. Cryogenic structures of superconducting coils for fusion experimental reactor 'ITER'

    International Nuclear Information System (INIS)

    Nakajima, Hideo; Iguchi, Masahide; Hamada, Kazuya; Okuno, Kiyoshi; Takahashi, Yoshikazu; Shimamoto, Susumu

    2013-01-01

    This paper describes both structural materials and structural design of the Toroidal Field (TF) coil and Central Solenoid (CS) for the International Thermonuclear Experimental Reactor (ITER). All the structural materials used in the superconducting coil system of the ITER are austenitic stainless steels. Although 316LN is used in the most parts of the superconducting coil system, the cryogenic stainless steels, JJ1 and JK2LB, which were newly developed by the Japan Atomic Energy Agency (JAEA) and Japanese steel companies, are used in the highest stress area of the TF coil case and the whole CS conductor jackets, respectively. These two materials became commercially available based on demonstration of productivity and weldability of materials, and evaluations of 4 K mechanical properties of trial products including welded parts. Structural materials are classified into five grades depending on stress distribution in the TF coil case. JAEA made an industrial specification for mass production based on the ITER requirements. In order to simplify quality control in mass production, JAEA has used materials specified in the material section of 'Codes for Fusion Facilities - Rules on Superconducting Magnet Structure (2008)' issued by the Japan Society of Mechanical Engineers (JSME) in October 2008, which was established using an extrapolation method of 4 K material strengths from room temperature strength and chemical compositions developed by JAEA. It enables steel suppliers to easily control the quality of products at room temperature. JAEA has already started actual production with several manufacturing companies. The first JJ1 product to be used in the TF coil case and the first JK2LB jackets for CS were completed in October and September 2013, respectively. (author)

  7. Magnetic structures of holmium-lutetium alloys and superlattices

    DEFF Research Database (Denmark)

    Swaddling, P.P.; Cowley, R.A.; Ward, R.C.C.

    1996-01-01

    Alloys and superlattices of Ho and Lu have been grown using molecular beam epitaxy and their magnetic structures determined using neutron-scattering techniques. The 4f moments in the alloys form a helix at all compositions with the moments aligned in the basal plane perpendicular to the wave vector...... of the helix remaining coherent through the nonmagnetic Lu blocks. The neutron scattering from the superlattices is consistent with a model in which there are different phase advances of the helix turn angle through the Ho and Lu blocks, but with a localized moment on the Ho sites only. A comparison...... of Ho and Lu. At low temperatures, for superlattices with fewer than approximately twenty atomic planes of Ho, the Ho moments within a block undergo a phase transition from helical to ferromagnetic order, with the coupling between successive blocks dependent on the thickness of the Lu spacer....

  8. QuikForm: Intelligent deformation processing of structural alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bourcier, R.J.; Wellman, G.W.

    1994-09-01

    There currently exists a critical need for tools to enhance the industrial competitiveness and agility of US industries involved in deformation processing of structural alloys. In response to this need, Sandia National Laboratories has embarked upon the QuikForm Initiative. The goal of this program is the development of computer-based tools to facilitate the design of deformation processing operations. The authors are currently focusing their efforts on the definition/development of a comprehensive system for the design of sheet metal stamping operations. The overall structure of the proposed QuikForm system is presented, and the focus of their thrust in each technical area is discussed.

  9. Vacuum Plasma Spraying W-coated Reduced Activation Structural Steels for Fusion Plasma Facing Components

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Sanghoon; Kim, Tae Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Tungsten (W) and its alloys are considered as candidate materials for plasma facing materials of the first wall and diverter components in fusion reactor systems because of high sputtering resistance and low tritium retention in a fusion environment. Therefore, it is considered that the joining between W and reduced activation structural steels, and its evaluation, are critical issues for the development of fusion reactors. However, the joining between these materials is a very challenging process because of significant differences in their physical properties, particularly the mismatch of coefficients of thermal expansion (CTE). For instance, the CTE of pure W is known to be about 4.3Χ10{sup -6}K{sup -1}; however, that of martensitic steels reaches over three times, about 12-14Χ10{sup -6}K{sup -1} at room temperature even up to 373K. Nevertheless, several joining techniques have been developed for joining between W and structural steels, such as a vapor deposition method, brazing and diffusion bonding. Meanwhile, vacuum plasma spraying (VPS) is supposed to be one of the prospective methods to fabricate a sufficient W layer on the steel substrates because of the coating of a large area with a relatively high fabricating rate. In this study, the VPS method of W powders on reduced activation steels was employed, and its microstructure and hardness distribution were investigated. ODS ferritic steels and F82H steel were coated by VPS-W, and the microstructure and hardness distribution were investigated. A microstructure analysis revealed that pure W was successfully coated on steel substrates by the VPS process without an intermediate layer, in spite of a mismatch of the CTE between dissimilar materials. After neutron irradiation, irradiation hardening significantly occurred in the VPSW. However, the hardening of VPS-W was lesser than that of bulk W irradiated HFIR at 773K. Substrate materials, ODS ferritic steels, and F82H steel, did not show irradiation hardening

  10. Proceedings of the Office of Fusion Energy/DOE workshop on ceramic matrix composites for structural applications in fusion reactors

    International Nuclear Information System (INIS)

    Jones, R.H.; Lucas, G.E.

    1990-11-01

    A workshop to assess the potential application of ceramic matrix composites (CMCs) for structural applications in fusion reactors was held on May 21--22, 1990, at University of California, Santa Barbara. Participants included individuals familiar with materials and design requirements in fusion reactors, ceramic composite processing and properties and radiation effects. The primary focus was to list the feasibility issues that might limit the application of these materials in fusion reactors. Clear advantages for the use of CMCs are high-temperature operation, which would allow a high-efficiency Rankine cycle, and low activation. Limitations to their use are material costs, fabrication complexity and costs, lack of familiarity with these materials in design, and the lack of data on radiation stability at relevant temperatures and fluences. Fusion-relevant feasibility issues identified at this workshop include: hermetic and vacuum properties related to effects of matrix porosity and matrix microcracking; chemical compatibility with coolant, tritium, and breeder and multiplier materials, radiation effects on compatibility; radiation stability and integrity; and ability to join CMCs in the shop and at the reactor site, radiation stability and integrity of joints. A summary of ongoing CMC radiation programs is also given. It was suggested that a true feasibility assessment of CMCs for fusion structural applications could not be completed without evaluation of a material ''tailored'' to fusion conditions or at least to radiation stability. It was suggested that a follow-up workshop be held to design a tailored composite after the results of CMC radiation studies are available and the critical feasibility issues are addressed

  11. Fusion peptide of influenza hemagglutinin requires a fixed angle boomerang structure for activity.

    Science.gov (United States)

    Lai, Alex L; Park, Heather; White, Judith M; Tamm, Lukas K

    2006-03-03

    The fusion peptide of influenza hemagglutinin is crucial for cell entry of this virus. Previous studies showed that this peptide adopts a boomerang-shaped structure in lipid model membranes at the pH of membrane fusion. To examine the role of the boomerang in fusion, we changed several residues proposed to stabilize the kink in this structure and measured fusion. Among these, mutants E11A and W14A expressed hemagglutinins with hemifusion and no fusion activities, and F9A and N12A had no effect on fusion, respectively. Binding enthalpies and free energies of mutant peptides to model membranes and their ability to perturb lipid bilayer structures correlated well with the fusion activities of the parent full-length molecules. The structure of W14A determined by NMR and site-directed spin labeling features a flexible kink that points out of the membrane, in sharp contrast to the more ordered boomerang of the wild-type, which points into the membrane. A specific fixed angle boomerang structure is thus required to support membrane fusion.

  12. Perspective on present and future alloy development efforts on austenitic stainless steels for fusion application

    International Nuclear Information System (INIS)

    Maziasz, P.J.

    1984-01-01

    The purpose of this paper is to address important questions concerning how to effect further alloy development of austenitic stainless steels for resistance, and to what extent the behavior of other properties under irradiation, such as strength/embrittlement, fatigue/irradiation creep, corrosion (under irradiation), and radiation-induced activation must be influenced. To summarize current understanding, helium has been found to have major effects on swelling and embrittlement, but several metallurgical avenues are available for significant improvement relative to type 316 stainless steel. Studies on fatigue and irradiation creep, particularly including helium effects, are preliminary but have yet to reveal engineering problems requiring additional alloy development remedies. The effects of irradiation on corrosion behavior are unknown, but higher alloy nickel contents make thermal corrosion in lithium worse. 67 refs

  13. A study of the formation of Cr-surface alloyed layer on structural alloy steel by Co2 laser

    International Nuclear Information System (INIS)

    Kim, T.H.; Han, W.S.

    1986-01-01

    In order to improve wear and erosion-resistances of a structural alloy steel (SNCM 8) during heat-cycling, chromium-alloyed layers were produced on the surface by irradiating Co 2 laser. Specimens were prepared either by electroplating of hard-chromium or coating of chromium powders on the steel followed by the laser treatment. Index values, which related the depth and the width of the alloyed layers to the scanning speed of laser, for both samples are experimentally measured. At a fixed scanning speed, while both samples resulted in a similar depth of the alloyed layers, the chromium powder coated specimen showed larger width of the alloyed layer than the chromium electroplated one. The hardness values of the alloyed layers in both samples were slightly lower than that of the martensitic region beneath the alloyed layers. But they are considerably higher than those of steel matrices. Regardless of the prior treatments before laser irradiation, distributions of chromium were fairly uniform throughout the alloyed layers. (Author)

  14. Phosphorus effect on structure and physical properties of iron-nickel alloys

    International Nuclear Information System (INIS)

    Berseneva, F.N.; Kalinin, V.M.; Rybalko, O.F.

    1982-01-01

    The structure and properties of iron-nickel alloys (30-50 % Ni) containing from 0.02 to 0.5 wt. % P have been investigated. It has been found that phosphorus solubility in iron-nickel alloys at most purified from impurities exceeds limiting solubility values usually observed for commercial alloys. Phosphide eutectics precipitation over the grain boundaries of studied alloys occurs but with phosphorus content equal 0.45 wt. %. The 0.4 wt. % P addition in invar alloys increases saturation magnetization and the Curie point and leads to a more homogeneous structure

  15. Structural formation of aluminide phases on titanium alloy during annealing

    International Nuclear Information System (INIS)

    Mamaeva, A.A.; Romankov, S.E.; Sagdoldina, Zh.

    2006-01-01

    Full text: The aluminum layer on the surface of titanium alloy has been formed by thermal deposition. The structural formation of aluminide phases on the surface has been studied. The sequence of structural transformations at the Ti/Al interface is limited by the reaction temperature and time. The sequence of aluminide phase formation is occurred in compliance with Ti-Al equilibrium phase diagram. At the initial stages at the Ti/Al interface the Al3Ti alloy starts forming as a result of interdiffusion, and gradually the whole aluminum films is spent on the formation of this layer. The Al3Ti layer decomposes with the increase of temperature (>600C). At 800C the two-phase (Ti3Al+TiAl) layer is formed on the titanium surface. The TiAl compound is unstable and later on with the increase of the exposure time at 800C gradually transforms into the Ti3Al. The chain of these successive transformations leads to the formation of the continuous homogeneous layer consisting of the Ti3Al compound on the surface. At temperatures exceeding the allotropic transformation temperature (>900C) the Ti3Al compound starts decomposing. All structural changes taking place at the Ti/Al interface are accompanied by considerable changes in micro hardness. The structure of initial substrate influences on kinetics of phase transformation and microstructure development. (author)

  16. Electronic structure of disordered alloys, surfaces and interfaces

    CERN Document Server

    Turek, Ilja; Kudrnovský, Josef; Šob, Mojmír; Weinberger, Peter

    1997-01-01

    At present, there is an increasing interest in the prediction of properties of classical and new materials such as substitutional alloys, their surfaces, and metallic or semiconductor multilayers. A detailed understanding based on a thus of the utmost importance for fu­ microscopic, parameter-free approach is ture developments in solid state physics and materials science. The interrela­ tion between electronic and structural properties at surfaces plays a key role for a microscopic understanding of phenomena as diverse as catalysis, corrosion, chemisorption and crystal growth. Remarkable progress has been made in the past 10-15 years in the understand­ ing of behavior of ideal crystals and their surfaces by relating their properties to the underlying electronic structure as determined from the first principles. Similar studies of complex systems like imperfect surfaces, interfaces, and mul­ tilayered structures seem to be accessible by now. Conventional band-structure methods, however, are of limited use ...

  17. Researches focused on structure of aluminium alloys processed by rapid solidification, used in automotive industry

    International Nuclear Information System (INIS)

    Sfat, C.; Vasile, T.; Vasilescu, M.

    2001-01-01

    The paper present some new results focused on an aluminium high temperature alloy, obtained by 'melt spinning method'. alloy composition, processing conditions, resulted structures and the influence between them are presented. There are studied the two zone structures of the alloy and the relation between processing conditions and the characteristics of the zones, with implications on mechanical behavior in real conditions. The final conclusion show that is possible to control the structure in order to improve material behavior. (author)

  18. Development of bonding techniques of W and Cu-alloys for plasma facing components of fusion reactor with HIP method

    International Nuclear Information System (INIS)

    Saito, S.; Fukaya, K.; Ishiyama, S.; Eto, M.; Sato, K.; Akiba, M.

    1998-01-01

    W (tungsten) and Cu (copper)-alloys, like oxygen free high thermal conductivity (OFHC)-copper or dispersion strengthened (DS)-copper, are candidate materials for plasma facing components(PFC) of TOKAMAK type fusion reactor as armor tile and heat sink, respectively. However, PFC are exposed to cyclic high heat load and heavy irradiation by 14 MeV neutrons. Under these conditions, thermal stresses at bonding interface and irradiation damage will decrease the bonding strength between W and Cu alloys. Therefore, it is necessary to develop a reliable bonding techniques in order to make PFC with enough integrity. We have applied the hot isostatic press (HIP) method to bond W with Cu-alloys. In this experiments, to optimize HIP bonding conditions, four point bending tests were performed for different bonding conditions at temperatures from R.T. to 873 K and we obtained an optimum HIP bonding condition for W and OFHC-Cu as 1273 SK x 2 hours x 98 ∼ 147 MPa. Tensile tests were also performed at the same temperature range. The tensile strength of the bonded W / Cu was almost equal to that of OFHC Cu which was HIPed at the same conditions. Tensile specimens were broken at the bonding interface or OFHC-Cu side. Bonding tests of W and DS-Cu showed that HIP was not successful because tungsten oxide was produced at the bonding interface and residual stresses were not relaxed. Therefore, it was concluded that some insert materials will be needed to bond W and DS-Cu. (author)

  19. Density and Structure Analysis of Molten Ni-W Alloys

    Institute of Scientific and Technical Information of China (English)

    Feng XIAO; Liang FANG

    2004-01-01

    Density of molten Ni and Ni-W alloys was measured in the temperature range of 1773~1873 K with a sessile drop method.The density of molten Ni and Ni-W alloys trends to decrease with increasing temperature. The density and molar volume of the alloys trend to increase with increasing W concentration in the alloys. The calculation result shows an ideal mixing of Ni-W alloys.

  20. Fusion and characterization of a Cu-Zn-Al-Ni alloy of nuclear interest

    International Nuclear Information System (INIS)

    Zamora R, L.; Arenas A, J.A.; Santana M, J.S.

    2003-01-01

    The first part of the work was made in the Melting Laboratory where an ingot of each alloy was obtained under the same conditions. When having the ingots physically, the following thing consisted, in using different techniques for their characterization in the laboratories of Metallography, Scanning Electron Microscopy, (Sem), X-ray diffraction (XRD) and that of mechanical assays. (Author)

  1. Atomic Structure of Au−Pd Bimetallic Alloyed Nanoparticles

    KAUST Repository

    Ding, Yong

    2010-09-08

    Using a two-step seed-mediated growth method, we synthesized bimetallic nanoparticles (NPs) having a gold octahedron core and a palladium epitaxial shell with controlled Pd-shell thickness. The mismatch-release mechanism between the Au core and Pd shell of the NPs was systematically investigated by high-resolution transmission electron microscopy. In the NPs coated with a single atomic layer of Pd, the strain between the surface Pd layer and the Au core is released by Shockley partial dislocations (SPDs) accompanied by the formation of stacking faults. For NPs coated with more Pd (>2 nm), the stacking faults still exist, but no SPDs are found. This may be due to the diffusion of Au atoms into the Pd shell layers to eliminate the SPDs. At the same time, a long-range ordered L11 AuPd alloy phase has been identified in the interface area, supporting the assumption of the diffusion of Au into Pd to release the interface mismatch. With increasing numbers of Pd shell layers, the shape of the Au-Pd NP changes, step by step, from truncated-octahedral to cubic. After the bimetallic NPs were annealed at 523 K for 10 min, the SPDs at the surface of the NPs coated with a single atomic layer of Pd disappeared due to diffusion of the Au atoms into the surface layer, while the stacking faults and the L11 Au-Pd alloyed structure remained. When the annealing temperature was increased to 800 K, electron diffraction patterns and diffraction contrast images revealed that the NPs became a uniform Au-Pd alloy, and most of the stacking faults disappeared as a result of the annealing. Even so, some clues still support the existence of the L11 phase, which suggests that the L11 phase is a stable, long-range ordered structure in Au-Pd bimetallic NPs. © 2010 American Chemical Society.

  2. The Structure of the Silumin Coat on Alloy Cast Steels

    Directory of Open Access Journals (Sweden)

    T. Szymczak

    2012-04-01

    Full Text Available The work presents the analysis results of the structure of the coat obtained by dipping in silumin AlSi5 of two grades of alloy cast steel: GX6CrNiTi18-10 (LH18N9T and GX39Cr13 (LH14. The temperature of the silumin bath was 750±5°C, and the hold-up time of the cast steel element τ = 180 s. The absolute thickness of the coat obtained in the given conditions was g = 104 μm on cast steel GX6CrNiTi18-10 and g = 132 μm on GX39Cr13. The obtained coat consisted of three layers of different phase structure. The first layer from the base “g1`” was constructed of the phase AlFe including Si and alloy additives of the tested cast steel grades: Cr and Ni (GX6CrNiTi18-10 and Cr (GX39Cr13. The second layer “g1``” of intermetallic phases AlFe which also contains Si and Cr crystallizes on it. The last, external layer “g2” of the coat consists of the silumin containing the intermetallic phases AlFeSi which additionally can contain alloy additives of the cast steel. It was shown that there were no carbides on the coat of the tested cast steels which are the component of their microstructure, as it took place in the case of the coat on the high speed steels.

  3. Paramyxovirus membrane fusion: Lessons from the F and HN atomic structures

    International Nuclear Information System (INIS)

    Lamb, Robert A.; Paterson, Reay G.; Jardetzky, Theodore S.

    2006-01-01

    Paramyxoviruses enter cells by fusion of their lipid envelope with the target cell plasma membrane. Fusion of the viral membrane with the plasma membrane allows entry of the viral genome into the cytoplasm. For paramyxoviruses, membrane fusion occurs at neutral pH, but the trigger mechanism that controls the viral entry machinery such that it occurs at the right time and in the right place remains to be elucidated. Two viral glycoproteins are key to the infection process-an attachment protein that varies among different paramyxoviruses and the fusion (F) protein, which is found in all paramyxoviruses. For many of the paramyxoviruses (parainfluenza viruses 1-5, mumps virus, Newcastle disease virus and others), the attachment protein is the hemagglutinin/neuraminidase (HN) protein. In the last 5 years, atomic structures of paramyxovirus F and HN proteins have been reported. The knowledge gained from these structures towards understanding the mechanism of viral membrane fusion is described

  4. Fabrication and structure of bulk nanocrystalline Al-Si-Ni-mishmetal alloys

    International Nuclear Information System (INIS)

    Latuch, Jerzy; Cieslak, Grzegorz; Kulik, Tadeusz

    2007-01-01

    Al-based alloys of structure consisting of nanosized Al crystals, embedded in an amorphous matrix, are interesting for their excellent mechanical properties, exceeding those of the commercial crystalline Al-based alloys. Recently discovered nanocrystalline Al alloys containing silicon (Si), rare earth metal (RE) and late transition metal (Ni), combine high tensile strength and good wear resistance. The aim of this work was to manufacture bulk nanocrystalline alloys from Al-Si-Ni-mishmetal (Mm) system. Bulk nanostructured Al 91-x Si x Ni 7 Mm 2 (x = 10, 11.6, 13 at.%) alloys were produced by ball milling of nanocrystalline ribbons followed by high pressure hot isostating compaction

  5. Irradiation effects on the ductility of fusion reactor structural materials

    International Nuclear Information System (INIS)

    Boudamous, F.

    1986-10-01

    Austenitic and ferritic-martensitic stainless steels have been proposed as first wall structural materials for the next generation of fusion devices. In order to study the effect of high temperature irradiation on their tensile properties, specimens of the steel AISI 316 L (CEC reference), of the martensitic steel W. Nr 1.4914 and of the duplex ferritic-martensitic steel EM12 have been irradiated in the BR2 reactor in Mol. The austenitic steel was irradiated at 470 0 C to about 1.1 10 22 n/cm 2 ( E>0.1 MeV) while the ferritic-martensitic steels were irradiated at 590 0 C to about 7.7 10 22 n/cm 2 (E>0.1 MeV). The tensile tests of the 316 L steel have been performed between 250 and 750 0 C. Below around 550 0 C, the yield stress after irradiation increased from about 160 to 270 MPa and the total elongation decreased from 42 to about 26%. At 750 0 C, the yield stress increase was small but the total elongation decreased from 60 to only 10%. At this temperature, the rupture of the irradiated specimen was intergranular while all the other specimens presented a transgranular rupture. At 650 0 C the variations were intermediate. The change of the ultimate tensile strength was small at all test temperatures. The EM12 and W. Nr 1.4914 steels tested only at 550 0 C, showed a decrease of the yield and tensile strength as well as an increase of the total elongation. The same tests performed on specimens which have been heat treated in parallel showed that the observed changes were due, in a large part, if not completely, to the maintenance of steels at high temperature

  6. Fusion cutting of aluminum, magnesium, and titanium alloys using high-power fiber laser

    Science.gov (United States)

    Scintilla, Leonardo Daniele; Tricarico, Luigi

    2013-07-01

    The effects of cutting speed and assist gas pressure on laser cutting of 1-mm thick Al 1050, AZ31, and Ti6Al4V lightweight alloys are experimentally investigated. Fiber laser cutting of these materials is not broadly investigated and the acquisition of a new level of knowledge is of fundamental importance for applications like sheet metal trimming in automotive industry. The main process outputs are in depth compared with results reported in literature and obtained by cutting with CO2 and Nd∶YAG lasers. The good cut quality, the high productivity, and the easy delivery of the beam obtained at the same time, corroborate the advantage of using fiber lasers for thin sheets lightweight alloys cutting.

  7. The structure of the alphinizing coat on alloy steels

    Directory of Open Access Journals (Sweden)

    S. Pietrowski

    2008-12-01

    Full Text Available In this paper results of the structure of the coat alphinizing in AlSi5 silumin on alloy steels: acid-proof 1H18N9T (X6CrNiTi18-10 and high speed SW18 (HS18-0-1 were presented. The temperature of the alphinizing bath was amounts to750±5°C, and immersion time of the element τ = 180s. It was shown, that there is the different “g” coat thickness on testing steels. On the 1H18N9T steel it amounts to g = 52μm, and on the SW18 steel – g = 203μm. Regardless of a grade of testing alloy steels the coat consist of three layers with diversified phasic structure. There is different chemical composition of coat layers on testing steels. The first layer from the base consist of AlFe phase containing alloy addictions of steels: Cr and Ni (1H18N9T and W, V and Cr (SW18. On this layer crystallize the second layer of intermetallic phases. It is the phase containing the main alloy addiction of steels: AlFeCr (1H18N9T and AlFeW (SW18. The last, outside layer consist of silumin containing AlFeNi intermetallic phases on the 1H18N9T steel and AlFeW on the SW18 steel. Regardless of the grade of testing steels there is Si element in all layers of the coat. There are morphological differences in tested layers. The second layer (AlFeW phase inside the coat on the SW18 steel consist of faced crystals growing into in outside silumin layer. On the 1H18N9T steel a boundary between transient and outside layer is more uniform. Free separations of intermetallic phases inside silumin layer on the 1H18N9T steel have lamellar and on the SW18 steel – faced form.

  8. Features of ultrafine-grained structure forming in Zr-1Nb alloy

    Energy Technology Data Exchange (ETDEWEB)

    Stepanova, Ekaterina N.; Prosolov, Konstantin A. [National Research Tomsk Polytechnic University, Tomsk (Russian Federation); Grabovetskaya, Galina P.; Mishin, Ivan P. [Institute of Strength Physics and Materials Science of Siberian Branch of Russian Academy of Sciences, Tomsk (Russian Federation)

    2013-07-01

    Ultrafine-grained structure forming by the method combined reversible hydrogenation and hot pressing in Zr-1Nb alloy was investigated. Preliminary hydrogenation to concentrations of (0.14–0.4) % at 873 K is found to lead to yield strength decreasing in Zr-1Nb alloy during hot pressing by 1,5–2 times. During uniaxial compression at (70–72) % under isothermal conditions at a temperature of 873 K in Zr-1Nb alloy, hydrogenated to concentration of 0.22 %, homogeneous ultrafine grained structure with an average grain size of 0,4 P m was formed. Key words: zirconium alloy, ultrafine-grained structure, hydrogen.

  9. Advanced fusion welding processes, solid state joining and a successful marriage. [production of aerospace structures

    Science.gov (United States)

    Miller, F. R.

    1972-01-01

    Joining processes for aerospace systems combine fusion welding and solid state joining during production of metal structures. Detailed characteristics of electron beam welding, plasma arc welding, diffusion welding, inertia welding and weldbond processes are discussed.

  10. Measles Virus Fusion Protein: Structure, Function and Inhibition

    Directory of Open Access Journals (Sweden)

    Philippe Plattet

    2016-04-01

    Full Text Available Measles virus (MeV, a highly contagious member of the Paramyxoviridae family, causes measles in humans. The Paramyxoviridae family of negative single-stranded enveloped viruses includes several important human and animal pathogens, with MeV causing approximately 120,000 deaths annually. MeV and canine distemper virus (CDV-mediated diseases can be prevented by vaccination. However, sub-optimal vaccine delivery continues to foster MeV outbreaks. Post-exposure prophylaxis with antivirals has been proposed as a novel strategy to complement vaccination programs by filling herd immunity gaps. Recent research has shown that membrane fusion induced by the morbillivirus glycoproteins is the first critical step for viral entry and infection, and determines cell pathology and disease outcome. Our molecular understanding of morbillivirus-associated membrane fusion has greatly progressed towards the feasibility to control this process by treating the fusion glycoprotein with inhibitory molecules. Current approaches to develop anti-membrane fusion drugs and our knowledge on drug resistance mechanisms strongly suggest that combined therapies will be a prerequisite. Thus, discovery of additional anti-fusion and/or anti-attachment protein small-molecule compounds may eventually translate into realistic therapeutic options.

  11. Structural properties of hydrogen isotopes in solid phase in the context of inertial confinement fusion

    Directory of Open Access Journals (Sweden)

    Guerrero Carlo

    2013-11-01

    Full Text Available Quality of Deuterium-Tritium capsules is a critical aspect in Inertial Confinement Fusion. In this work, we present a Quantum Molecular Dynamics methodology able to model hydrogen isotopes and their structural molecular organisation at extreme pressures and cryogenic temperatures (< 15 K. Our study sets up the basis for a future analysis on the mechanical and structural properties of DT-ice in inertial confinement fusion (ICF target manufacturing conditions.

  12. High-Entropy Alloys in Hexagonal Close-Packed Structure

    Science.gov (United States)

    Gao, M. C.; Zhang, B.; Guo, S. M.; Qiao, J. W.; Hawk, J. A.

    2016-07-01

    The microstructures and properties of high-entropy alloys (HEAs) based on the face-centered cubic and body-centered cubic structures have been studied extensively in the literature, but reports on HEAs in the hexagonal close-packed (HCP) structure are very limited. Using an efficient strategy in combining phase diagram inspection, CALPHAD modeling, and ab initio molecular dynamics simulations, a variety of new compositions are suggested that may hold great potentials in forming single-phase HCP HEAs that comprise rare earth elements and transition metals, respectively. Experimental verification was carried out on CoFeReRu and CoReRuV using X-ray diffraction, scanning electron microscopy, and energy dispersion spectroscopy.

  13. Precipitation structures and mechanical properties of Al-Li-Zr alloy containing V

    International Nuclear Information System (INIS)

    Ying, J.K.; Ohashi, T.

    1999-01-01

    It is known that Al-Li alloys possess high elastic modulus and low density, and the metastable δ' (Al 3 Li) precipitate in these alloys affords considerable strengthening effect. However, with the strengthening resulting from the precipitation of δ' which is coherent with the matrix, these alloys suffer from low ductility and fracture toughness. It seems that the loss of ductility is the slip localization which occurs as a result of slip planes during deformation in connection with the specific hardening mechanism. As a result it indicates typical intergranular fracture. On the one hand, zirconium is used in many aluminum alloys to inhibit recrystallization during alloy processing. When zirconium is present in the alloy grain refinement occurs, which consequently, is considered as a factor that reduces the slip distance, and lowers the stress concentration across grain boundaries and at grain boundary triple points. Nevertheless, if only zirconium is added in Al-Li alloy it still shows intergranular fracture. By Zedaris et al., equilibrium phase Al 3 (Zr,V) in Al-Zr alloy containing V reduces the lattice mismatch along the c-axis with Al and, the L1 2 -structure metastable precipitates Al 3 (Zr,V) in Al-Zr-V alloys are stable at elevated temperature. Therefore, it is interesting to elucidate the effect of V in Al-Li-Zr alloy at the precipitation structures and mechanical properties of these alloys

  14. Structure and Mechanical Properties of Al-Cu-Fe-X Alloys with Excellent Thermal Stability

    Directory of Open Access Journals (Sweden)

    Andrea Školáková

    2017-11-01

    Full Text Available In this work, the structure and mechanical properties of innovative Al-Cu-Fe based alloys were studied. We focused on preparation and characterization of rapidly solidified and hot extruded Al-Cu-Fe, Al-Cu-Fe-Ni and Al-Cu-Fe-Cr alloys. The content of transition metals affects mechanical properties and structure. For this reason, microstructure, phase composition, hardness and thermal stability have been investigated in this study. The results showed exceptional thermal stability of these alloys and very good values of mechanical properties. Alloying by chromium ensured the highest thermal stability, while nickel addition refined the structure of the consolidated alloy. High thermal stability of all tested alloys was described in context with the transformation of the quasicrystalline phases to other types of intermetallics.

  15. Computing elastic anisotropy to discover gum-metal-like structural alloys

    Science.gov (United States)

    Winter, I. S.; de Jong, M.; Asta, M.; Chrzan, D. C.

    2017-08-01

    The computer aided discovery of structural alloys is a burgeoning but still challenging area of research. A primary challenge in the field is to identify computable screening parameters that embody key structural alloy properties. Here, an elastic anisotropy parameter that captures a material's susceptibility to solute solution strengthening is identified. The parameter has many applications in the discovery and optimization of structural materials. As a first example, the parameter is used to identify alloys that might display the super elasticity, super strength, and high ductility of the class of TiNb alloys known as gum metals. In addition, it is noted that the parameter can be used to screen candidate alloys for shape memory response, and potentially aid in the optimization of the mechanical properties of high-entropy alloys.

  16. Structure and Mechanical Properties of Al-Cu-Fe-X Alloys with Excellent Thermal Stability.

    Science.gov (United States)

    Školáková, Andrea; Novák, Pavel; Mejzlíková, Lucie; Průša, Filip; Salvetr, Pavel; Vojtěch, Dalibor

    2017-11-05

    In this work, the structure and mechanical properties of innovative Al-Cu-Fe based alloys were studied. We focused on preparation and characterization of rapidly solidified and hot extruded Al-Cu-Fe, Al-Cu-Fe-Ni and Al-Cu-Fe-Cr alloys. The content of transition metals affects mechanical properties and structure. For this reason, microstructure, phase composition, hardness and thermal stability have been investigated in this study. The results showed exceptional thermal stability of these alloys and very good values of mechanical properties. Alloying by chromium ensured the highest thermal stability, while nickel addition refined the structure of the consolidated alloy. High thermal stability of all tested alloys was described in context with the transformation of the quasicrystalline phases to other types of intermetallics.

  17. Hydrogen and deuterium transport and inventory parameters through W and W-alloys for fusion reactor applications

    Science.gov (United States)

    Benamati, G.; Serra, E.; Wu, C. H.

    2000-12-01

    The aim of this work is to measure the hydrogen/deuterium transport and inventory parameters in relevant structural and/or armour materials for the International Thermonuclear Experimental Reactor (ITER) divertor such as W and W-alloys. The W-alloys: W, W + 1% La 2O 3 and W + 5% Re have been investigated. The materials were supplied from the Metallwerk Plansee GmbH (Austria). Measurements were conducted using a time-dependent permeation method over the temperature range 673-873 K with hydrogen and deuterium pressures in the range 10-100 kPa (100-1000 mbar). The samples were also characterized using optical microscopy, SEM and energy dispersive spectroscopy (EDS) in order to investigate the composition, microstructure and morphology of the surfaces and cross-sections through the samples.

  18. Structure and magnetic properties of nanostructured MnNi alloys fabricated by mechanical alloying and annealing treatments

    Science.gov (United States)

    Jalal, T.; Hossein Nedjad, S.; Khalili Molan, S.

    2013-05-01

    A nearly equiatomic MnNi alloy was fabricated from the elemental powders by means of mechanical alloying in a planetary ball milling apparatus. X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and measurements of magnetization were conducted to identify the structural states and properties of the prepared alloys. After ball milling for 20 h, a disordered face-centered cubic (f.c.c.) solid solution was formed which increased in lattice parameter by further milling up to 50 h. An exothermic reaction took place at around 300-400°C during continuous heating of the disordered f.c.c. solid solution. This reaction is attributed to a structural ordering leading to the formation of a face-centered tetragonal (f.c.t.) phase with L10 type ordering. Examination of the magnetic properties indicated that the structural ordering increases remnant magnetization and decreases coerecivity.

  19. Structural investigation of Fe(Cu)ZrB amorphous alloy

    Energy Technology Data Exchange (ETDEWEB)

    Duhaj, P. [Slovenska Akademia Vied, Bratislava (Slovakia). Fyzikalny Ustav; Matko, I. [Slovenska Akademia Vied, Bratislava (Slovakia). Fyzikalny Ustav; Svec, P. [Slovenska Akademia Vied, Bratislava (Slovakia). Fyzikalny Ustav; Sitek, J. [Department of Nuclear Physics and Technology, Slovak Technical University, 81219 Bratislava (Slovakia); Janickovic, D. [Slovenska Akademia Vied, Bratislava (Slovakia). Fyzikalny Ustav

    1996-07-01

    The crystallization process in Fe{sub 86}(Cu{sub 1})Zr{sub 7}B{sub 6} and Fe{sub 87}Zr{sub 7}B{sub 6} is investigated using the methods of transmission electron microscopy, electron and X-ray diffraction and resistometry. Two crystallization reactions take place during thermal annealing of amorphous Fe{sub 86}(Cu{sub 1})Zr{sub 7}B{sub 6} and Fe{sub 87}Zr{sub 7}B{sub 6} alloys. In both alloys the first crystallization begins with the formation of nanocrystalline {alpha}-Fe at temperature to approximately 800 K. The second crystallization starts above 1000 K; the nanocrystalline phase dissolves and together with the remaining amorphous matrix form rough grains of {alpha}-Fe and dispersed Fe{sub 23}Zr{sub 6} phases. From Moessbauer spectroscopy it seems that there exist two neighbourhoods of Fe atoms in the amorphous structure. One of them is characterized by low Zr content and is responsible for the high-field component of the hyperfine field distribution p(H). The second one is rich in Zr and B and is responsible for the low-field component of p(H). This is in accord with the observation of two crystallization steps separated by a large interval of temperatures due to the existence of two chemically different regions or clusters. (orig.)

  20. Structural investigation of Fe(Cu)ZrB amorphous alloy

    International Nuclear Information System (INIS)

    Duhaj, P.; Janickovic, D.

    1996-01-01

    The crystallization process in Fe 86 (Cu 1 )Zr 7 B 6 and Fe 87 Zr 7 B 6 is investigated using the methods of transmission electron microscopy, electron and X-ray diffraction and resistometry. Two crystallization reactions take place during thermal annealing of amorphous Fe 86 (Cu 1 )Zr 7 B 6 and Fe 87 Zr 7 B 6 alloys. In both alloys the first crystallization begins with the formation of nanocrystalline α-Fe at temperature to approximately 800 K. The second crystallization starts above 1000 K; the nanocrystalline phase dissolves and together with the remaining amorphous matrix form rough grains of α-Fe and dispersed Fe 23 Zr 6 phases. From Moessbauer spectroscopy it seems that there exist two neighbourhoods of Fe atoms in the amorphous structure. One of them is characterized by low Zr content and is responsible for the high-field component of the hyperfine field distribution p(H). The second one is rich in Zr and B and is responsible for the low-field component of p(H). This is in accord with the observation of two crystallization steps separated by a large interval of temperatures due to the existence of two chemically different regions or clusters. (orig.)

  1. A review of the structural characteristics of alloy 800

    International Nuclear Information System (INIS)

    Orr, J.

    1978-01-01

    The published literature is reviewed and supplemented by current information from the author's laboratory, to show the influence of various compositional, heat treatment and thermomechanical factors on the structural characteristics of Alloy 800. The features discussed include carbon, aluminium, titanium and boron, solution treatment, ageing treatments with and without applied strain, and cold working. Examples of the aspects reviewed include the effect of heat treatment and service or testing temperature on the austenite grain size, and the relative importance of M 23 C 6 and TiC, the influence of carbon level on gamma prime, the effect of residual or steady stress combined with time at temperature on changes in carbide or gamma prime morphology, and on the appearance of sigma or other intermetallic phases. The questions posed by these features are discussed generally, in terms of their effect on the mechanical properties at ambient and elevated temperatures and on the time-dependent properties. The review also suggests areas where further research work is required on Alloy 800. (Auth.)

  2. Hybrid Spintronic Structures With Magnetic Oxides and Heusler Alloys

    DEFF Research Database (Denmark)

    Xu, Y. B.; Hassan, S. S. A.; Wong, P. K. J.

    2008-01-01

    Hybrid spintronic structures, integrating half-metallic magnetic oxides and Heusler alloys with their predicted high spin polarization, are important for the development of second-generation spintronics with high-efficient spin injection. We have synthesized epitaxial magnetic oxide Fe3O4 on Ga......As(100) and the unit cell of the Fe3O4 was found to be rotated by 45 degrees to match the gallium arsenide GaAs. The films were found to have a bulk-like moment down to 3-4 nm and a low coercivity indicating a high-quality magnetic interface. The magnetization hysteresis loops of the ultrathin films...... are controlled by uniaxial magnetic anisotropy. The dynamic response of the sample shows a heavily damped precessional response to the applied field pulses. In the Heusler alloy system of Co-2 MnGa on GaAs, we found that the magnetic moment was reduced for thicknesses down to 10 nm, which may account...

  3. Electronic structure of disordered Fe-V alloys

    International Nuclear Information System (INIS)

    Krause, J.C.; Paduani, C.; Schaff, J.; Costa, M.I. Jr. da

    1998-01-01

    The first-principles discrete variational method is employed to investigate the electronic structure and local magnetic properties of disordered Fe-V alloys. The spin-polarized case is considered in the formalism of the local-spin-density approximation, with the exchange-correlation term of von Barth endash Hedin. The effect on the local magnetic properties of adding V atoms in the immediate neighborhood of iron atoms is investigated. The partial density of states, hyperfine field (H c ), magnetic moment (μ), and isomer shift are obtained for the central atom of the cluster. For the impurity V atom in the bcc iron host the calculated values for H c and μ are -203 kG and -0.86μ B , respectively. The isolated Fe atom in a bcc vanadium host exhibits a collapsed moment and acts as a receptor for electrons. In ordered alloys the calculations indicate also a vanishing moment at iron sites. copyright 1998 The American Physical Society

  4. Mechanical property changes induced in structural alloys by neutron irradiations with different helium to displacement ratios*1

    Science.gov (United States)

    Mansur, L. K.; Grossbeck, M. L.

    1988-07-01

    Effects of helium on mechanical properties of irradiated structural materials are reviewed. In particular, variations in response to the ratio of helium to displacement damage serve as the focus. Ductility in creep and tensile tests is emphasized. A variety of early work has led to the current concentration on helium effects for fusion reactor materials applications. A battery of techniques has been developed by which the helium to displacement ratio can be varied. Our main discussion is devoted to the techniques of spectral tailoring and isotopic alloying currently of interest for mixed-spectrum reactors. Theoretical models of physical mechanisms by which helium interacts with displacement damage have been developed in terms of hardening to dislocation motion and grain boundary cavitation. Austenitic stainless steels, ferritic/martensitic steels and vanadium alloys are considered. In each case, work at low strain rates, where the main problems may lie, at the helium to displacement ratios appropriate to fusion reactor materials is lacking. Recent experimental evidence suggests that both in-reactor and high helium results may differ substantially from post-irradiation or low helium results. It is suggested that work in these areas is especially needed.

  5. Examination of arrangement of alloy structural elements in models of metallographic structures

    International Nuclear Information System (INIS)

    Radwan, M.; Gibas, K.; Lybacka, K.; Narbantowicz, E.

    1986-01-01

    To verify the structure description method taking the probability of component concentration distributions in alloys into account, it is necessary to answer the following question: do the geometrical shapes of component arrangement which are visible on the autoradiographs as dark spots determine the type and parameters of the probability distribution. To solve the problem, 14 autoradiographic models representing different shapes of labelled compounds have been prepared and measured. The results show that different structures have a different distribution of the same element

  6. Electronic structure of disordered Cu-Ag alloys

    International Nuclear Information System (INIS)

    Razee, S.S.A.

    1994-08-01

    We present a self-consistent-field Korringa-Kohn-Rostoker coherent potential approximation study of the electronic structure of disordered Cu x Ag 1-x alloys for x=0.0, 0.25, 0.50, 0.75 and 1.0. In particular, we focus on the Fermi surface, density of states, and Bloch spectral density, and study how they evolve as a function of x. We find that, Fermi surface dimensions have a non-linear composition dependence. The disorder-induced smearing of the Fermi surface, as expected, is very high along the direction; both the Cu and Ag Fermi surfaces have a neck in this direction. Whenever possible we have compared our results with the available experimental data. (author). 34 refs, 4 figs

  7. On the rational alloying of structural chromium-nickel steels

    International Nuclear Information System (INIS)

    Astaf'ev, A.A.

    1982-01-01

    A study was made on the influence of chromium nickel, phosphorus on the critical brittleness temperature of Cr-Ni-Mo-V structural steels. It is shown that the critical brittleness temperature of these steels increases at chromium content more over than 2% and nickel content more than 2% in the result of carbide transformations during tempering. Increase of nickel content in Cr-Ni-Mo-V-steels strengthens the tendency to embrittlement during slow cooling, from tempering temperature owing to development of process of phosphorus grain-boundary segregation. Two mentioned mechanisms of embrittlement determine principles of rational steel alloying. The extreme dependence of the critical brittleness temperature on chromium and nickel content, which enables to choose the optimum composition of Cr-Ni-Mo-V-steels, was established

  8. NASA-UVA Light Aerospace Alloy and Structures Technology Program (LA2ST)

    Science.gov (United States)

    Gangloff, Richard P.; Scully, John R.; Stoner, Glenn E.; Thornton, Earl A.; Wawner, Franklin E., Jr.; Wert, John A.

    1993-01-01

    The NASA-UVA Light Aerospace Alloy and Structures Technology (LA2ST) Program continues a high level of activity. Progress achieved between 1 Jan. and 30 Jun. 1993 is reported. The objective of the LA2ST Program is to conduct interdisciplinary graduate student research on the performance of next generation, light weight aerospace alloys, composites, and thermal gradient structures in collaboration with NASA-Langley researchers. The following projects are addressed: environmental fatigue of Al-Li-Cu alloys; mechanisms of localized corrosion and environmental fracture in Al-Cu-Li-Mg-Ag alloy X2095 and compositional variations; the effect of zinc additions on the precipitation and stress corrosion cracking behavior of alloy 8090; hydrogen interactions with Al-Li-Cu alloy 2090 and model alloys; metastable pitting of aluminum alloys; cryogenic fracture toughness of Al-Cu-Li + In alloys; the fracture toughness of Weldalite (TM); elevated temperature cracking of advanced I/M aluminum alloys; response of Ti-1100/SCS-6 composites to thermal exposure; superplastic forming of Weldalite (TM); research to incorporate environmental effects into fracture mechanics fatigue life prediction codes such as NASA FLAGRO; and thermoviscoplastic behavior.

  9. Non-superconducting magnet structures for near-term, large fusion experimental devices

    International Nuclear Information System (INIS)

    File, J.; Knutson, D.S.; Marino, R.E.; Rappe, G.H.

    1980-10-01

    This paper describes the magnet and structural design in the following American tokamak devices: the Princeton Large Torus (PLT), the Princeton Divertor Experiment (PDX), and the Tokamak Fusion Test Reactor (TFTR). The Joint European Torus (JET), also presented herein, has a magnet structure evolved from several European programs and, like TFTR, represents state of the art magnet and structure design

  10. Structural and constitutional studies of some cerium-praseodymium alloys

    International Nuclear Information System (INIS)

    Altunbas, M.; Harris, I.R.

    1980-01-01

    Room temperature X-ray diffraction studies on some powdered Ce-Pr alloys indicate that the face-centred-cubic (fcc) structure extends from 0 to 65% Pr and the double hexagonal (dhcp) structure from 66 to 100% Pr, after a heat treatment of 600 0 C for 2 h and quickly cooling to room temperature. Variations of atomic volume with composition in both ranges indicate that the volume difference between the fcc form of praseodymium and the dhcp form is similar to that observed for α(dhcp) and β(fcc) lanthanum, whereas extrapolation to 100% Ce from the dhcp range gave an atomic volume for the dhcp Ce appreciably in excess of the atomic volume of fcc γ-Ce. This volume expansion is consistent with a slight change of the effective valency of the cerium atoms in the dhcp solid solutions when compared with the γ-Ce but there is uncertainty as to the precise atomic volume of dhcp β-Ce. The DTA studies indicate a narrow liquidus/solidus separation and the electrical resistivity and DTA measurements indicate a regular change with composition in the transition temperature of the high temperature bcc phase. For the dhcp-fcc transition there is a marked variation in the width of the hysteresis loop across the Ce-Pr system which can be correlated with the degree of plastic deformation involved in the transformation. There is a marked increase in the slope of the transition temperature with composition for the Pr-rich alloys and no such transition is observed for the praseodymium samples after one heating cycle. A possible dhcp-fcc transition, however, is indicated by the DTA traces of the commercially pure praseodymium sample on cycling with temperature and this has been attributed to the influence of interstitial impurities. (author)

  11. Robust biomimetic-structural superhydrophobic surface on aluminum alloy.

    Science.gov (United States)

    Li, Lingjie; Huang, Tao; Lei, Jinglei; He, Jianxin; Qu, Linfeng; Huang, Peiling; Zhou, Wei; Li, Nianbing; Pan, Fusheng

    2015-01-28

    The following facile approach has been developed to prepare a biomimetic-structural superhydrophobic surface with high stabilities and strong resistances on 2024 Al alloy that are robust to harsh environments. First, a simple hydrothermal treatment in a La(NO3)3 aqueous solution was used to fabricate ginkgo-leaf like nanostructures, resulting in a superhydrophilic surface on 2024 Al. Then a low-surface-energy compound, dodecafluoroheptyl-propyl-trimethoxylsilane (Actyflon-G502), was used to modify the superhydrophilic 2024 Al, changing the surface character from superhydrophilicity to superhydrophobicity. The water contact angle (WCA) of such a superhydrophobic surface reaches up to 160°, demonstrating excellent superhydrophobicity. Moreover, the as-prepared superhydrophobic surface shows high stabilities in air-storage, chemical and thermal environments, and has strong resistances to UV irradiation, corrosion, and abrasion. The WCAs of such a surface almost remain unchanged (160°) after storage in air for 80 days, exposure in 250 °C atmosphere for 24 h, and being exposed under UV irradiation for 24 h, are more than 144° whether in acidic or alkali medium, and are more than 150° after 48 h corrosion and after abrasion under 0.98 kPa for 1000 mm length. The remarkable durability of the as-prepared superhydrophobic surface can be attributed to its stable structure and composition, which are due to the existence of lanthanum (hydr)oxides in surface layer. The robustness of the as-prepared superhydrophobic surface to harsh environments will open their much wider applications. The fabricating approach for such robust superhydrophobic surface can be easily extended to other metals and alloys.

  12. Positron annihilation lifetime measurements of vanadium alloy and F82H irradiated with fission and fusion neutrons

    International Nuclear Information System (INIS)

    Sato, K.; Inoue, K.; Yoshiie, T.; Xu, Q.; Wakai, E.; Kutsukake, C.; Ochiai, K.

    2009-01-01

    V-4Cr-4Ti, F82H, Ni and Cu were irradiated with fission and fusion neutrons at room temperature and 473 K. Defect structures were analyzed and compared using positron annihilation lifetime measurement, and microstructural evolution was discussed. The mean lifetime of positrons (the total amount of residual defects) increased with the irradiation dose. The effect of cascade impact was detected in Ni at room temperature. The size and the number of vacancy clusters were not affected by the displacement rate in the fission neutron irradiation at 473 K for the metals studied. The vacancy clusters were not formed in V-4Cr-4Ti irradiated at 473 K in the range of 10 -6 -10 -3 dpa. In F82H irradiated at 473 K, the defect evolution was prevented by pre-existing defects. The mean lifetime of positrons in fission neutron irradiation was longer than that in fusion neutron irradiation in V-4Cr-4Ti at 473 K. It was interpreted that more closely situated subcascades were formed in the fusion neutron irradiation and subcascades interacted with each other, and consequently the vacancy clusters did not grow larger.

  13. The effect of the solidification mode on eutectic structure in Fe-C-V alloys

    International Nuclear Information System (INIS)

    Fras, E.; Guzik, E.

    1980-01-01

    The aim of the study was to determine such a chemical composition of Fe-C-V alloys which would ensure the formation of perfectly eutectic structures as well as to investigate the eutectic morphology of these alloys when undergoing bulk and directional solidification. Attempts have been done to get in situ composites from Fe-C-V alloys. The adopted testing methods as well as obtained results are described in detail. (H.M.)

  14. Transmission electron microscope study of fusion-environment radiation damage in iron and iron-chromium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Horton, L.L.S.

    1982-07-01

    A transmission electron microscopy study of radiation damage microstructures in iron and iron-chromium alloys has been performed. This study consisted of both qualitative and quantitative characterization of the dislocation and cavity microstructures, including determination of vacancy/interstitial character and Burgers vectors for dislocation loops and analysis of the cavity morphology. The effects of irradiation temperature, fluence, helium implantation, and chromium content were investigated. Neutron irradiation (iron specimens, 1 dpa, 455 to 1000 K) and triple-beam ion irradiation (Fe-10% Cr specimens, 10 dpa, 725 to 950 K; Fe-10% Cr specimens, 850 K, 0.3 to 100 dpa; and Fe, Fe-5% Cr, Fe-10% Cr specimens, 850 K, 10 dpa) were employed. In the triple-beam ion irradiation procedure, simultaneous bombardment with 4 MeV Fe/sup + +/ ions and energetic He/sup +/ and D/sub 2//sup +/ ions was used to simulate the fusion environment (10 at. ppM He/dpa and 41 at. ppM D/dpa). In addition, single-beam 4 MeV Fe/sup + +/ ion irradiations of Fe-10% Cr both with and without pre-injection of helium and deuterium were performed.

  15. Transmission electron microscope study of fusion-environment radiation damage in iron and iron-chromium alloys

    International Nuclear Information System (INIS)

    Horton, L.L.S.

    1982-07-01

    A transmission electron microscopy study of radiation damage microstructures in iron and iron-chromium alloys has been performed. This study consisted of both qualitative and quantitative characterization of the dislocation and cavity microstructures, including determination of vacancy/interstitial character and Burgers vectors for dislocation loops and analysis of the cavity morphology. The effects of irradiation temperature, fluence, helium implantation, and chromium content were investigated. Neutron irradiation (iron specimens, 1 dpa, 455 to 1000 K) and triple-beam ion irradiation (Fe-10% Cr specimens, 10 dpa, 725 to 950 K; Fe-10% Cr specimens, 850 K, 0.3 to 100 dpa; and Fe, Fe-5% Cr, Fe-10% Cr specimens, 850 K, 10 dpa) were employed. In the triple-beam ion irradiation procedure, simultaneous bombardment with 4 MeV Fe ++ ions and energetic He + and D 2 + ions was used to simulate the fusion environment (10 at. ppM He/dpa and 41 at. ppM D/dpa). In addition, single-beam 4 MeV Fe ++ ion irradiations of Fe-10% Cr both with and without pre-injection of helium and deuterium were performed

  16. Irradiation creep experiments on fusion reactor candidate structural materials

    International Nuclear Information System (INIS)

    Hausen, H.; Cundy, M.R.; Schuele, W.

    1991-01-01

    Irradiation creep rates were determined for annealed and cold-worked AMCR- and 316-type steel alloys in the high flux reactor at Petten, for various irradiation temperatures, stresses and for neutron doses up to 4 dpa. Primary creep elongations were found in all annealed materials. A negative creep elongation was found in cold-worked materials for stresses equal to or below about 100 MPa. An increase of the negative creep elongation is found for decreasing irradiation temperatures and decreasing applied stresses. The stress exponent of the irradiation creep rate in annealed and cold-worked AMCR alloys is n = 1.85 and n = 1.1, respectively. The creep rates of cold-worked AMCR alloys are almost temperature independent over the range investigated (573-693 K). The results obtained in the HFR at Petten are compared with those obtained in ORR and EBR II. The smallest creep rates are found for cold-worked materials of AMCR- and US-PCA-type at Petten which are about a factor two smaller than the creep rates obtained of US-316 at Petten or for US-PCA at ORR or for 316L at EBR II. The scatter band factor for US-PCA, 316L, US-316 irradiated in ORR and EBR II is about 1.5 after a temperature and damage rate normalization

  17. New alloys for structural application. Kikai kozoyo shin kinzoku zairyo

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, T [Kogakuin Univ., Tokyo (Japan)

    1993-01-15

    As recent advance on the scientific technologies is amazing, the materials having new function or excellent performance have been developed. Speaking on some recent examples, they can be divided roughly to one group belonging to invention of materials themselves such as oxide superconductors and compounds semi-conductors, and the other belonging to the products as invention of epoc-making material manufacturing methods such as noncrystalline alloys and particle dispersion reinforced alloys (ODS). In this report, first, some new metallic materials introduced relatively recently and converting many technical innovations in wide range of machinery field, such as titanium alloys, refractory alloys having nickel group, aluminium-lithium alloys, HSLA steels composed of reduced weight of alloy elements and having higher strengths than those of carbon-steels and various properties, intermetallic materials such as Ni3Al and others are described, and next, mechanical alloying and its particle dispersion reinforced alloys, liquid phase rapid cooling process and its noncrystalline alloy-rapid cooling cohesion powder sintering alloys, and others are summarized under the paths from their birth to present status. 31 refs., 12 figs., 5 tabs.

  18. Silicon carbide composites as fusion power reactor structural materials

    Energy Technology Data Exchange (ETDEWEB)

    Snead, L.L., E-mail: SneadLL@ORNL.gov [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Nozawa, T. [Fusion Research and Development Directorate, Japan Atomic Energy Agency, 2-4 Shirakata Shirane, Tokai, Ibaraki 319-1195 (Japan); Ferraris, M. [Politecnico di Torino-DISMIC c. Duca degli Abruzzi, 24I-10129 Torino (Italy); Katoh, Y. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Shinavski, R. [Hypertherm HTC, 18411 Gothard St., Units A/B/C, Huntington Beach, CA 92648 (United States); Sawan, M. [University of Wisconsin, Madison 417 Engineering Research Building, 1500 Engineering Drive Madison, WI 53706-1687 (United States)

    2011-10-01

    Silicon carbide was first proposed as a low activation fusion reactor material in the mid 1970s. However, serious development of this material did not begin until the early 1990s, driven by the emergence of composite materials that provided enhanced toughness and an implied ability to use these typically brittle materials in engineering application. In the decades that followed, SiC composite system was successfully transformed from a poorly performing curiosity into a radiation stable material of sufficient maturity to be considered for near term nuclear and non-nuclear systems. In this paper the recent progress in the understanding and of basic phenomenon related to the use of SiC and SiC composite in fusion applications will be presented. This work includes both fundamental radiation effects in SiC and engineering issues such as joining and general materials properties. Additionally, this paper will briefly discuss the technological gaps remaining for the practical application of this material system in fusion power devices such as DEMO and beyond.

  19. Structure, mechanical properties and grindability of dental Ti-10Zr-X alloys

    International Nuclear Information System (INIS)

    Ho, W.-F.; Cheng, C.-H.; Pan, C.-H.; Wu, S.-C.; Hsu, H.-C.

    2009-01-01

    This study aimed to investigate the structure, mechanical properties and grindability of a binary Ti-Zr alloy added to a series of alloying elements (Nb, Mo, Cr and Fe). The phase and structure of Ti-10Zr-X alloys were evaluated using an X-ray diffraction (XRD) for phase analysis and optical microscope for microstructure of the etched alloys. Three-point bending tests were performed using a desk-top mechanical tester. Grindability was evaluated by measuring the amount of metal volume removed after grinding for 1 min at each of the four rotational speeds of the wheel (500, 750, 1000 or 1200 m/min). Results were compared with c.p. Ti, which was chosen as a control. Results indicated that the phase/crystal structure, microstructure, mechanical properties and grindability of the Ti-10Zr alloy can be significantly changed by adding small amounts of alloying elements. The alloying elements Nb, Mo, Cr and Fe contributed significantly to increasing the grinding ratio under all grinding conditions, although the grinding rate of all the metals was found to be largely dependent on grinding speed. The Ti-10Zr-1Mo alloy showed increases in microhardness (63%), bending strength (40%), bending modulus (30%) and elastic recovery angle (180%) over those of c.p. Ti, and was also found to have better grindability. The Ti-10Zr-1Mo alloy could therefore be used for prosthetic dental applications if other conditions necessary for dental casting are met

  20. Adaptive structured dictionary learning for image fusion based on group-sparse-representation

    Science.gov (United States)

    Yang, Jiajie; Sun, Bin; Luo, Chengwei; Wu, Yuzhong; Xu, Limei

    2018-04-01

    Dictionary learning is the key process of sparse representation which is one of the most widely used image representation theories in image fusion. The existing dictionary learning method does not use the group structure information and the sparse coefficients well. In this paper, we propose a new adaptive structured dictionary learning algorithm and a l1-norm maximum fusion rule that innovatively utilizes grouped sparse coefficients to merge the images. In the dictionary learning algorithm, we do not need prior knowledge about any group structure of the dictionary. By using the characteristics of the dictionary in expressing the signal, our algorithm can automatically find the desired potential structure information that hidden in the dictionary. The fusion rule takes the physical meaning of the group structure dictionary, and makes activity-level judgement on the structure information when the images are being merged. Therefore, the fused image can retain more significant information. Comparisons have been made with several state-of-the-art dictionary learning methods and fusion rules. The experimental results demonstrate that, the dictionary learning algorithm and the fusion rule both outperform others in terms of several objective evaluation metrics.

  1. Electronic structure of the L-cysteine films on dental alloys studied by ultraviolet photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Ogawa, K; Takahashi, K; Azuma, J; Kamada, M; Tsujibayashi, T; Ichimiya, M

    2013-01-01

    The valence electronic structures of the dental alloys, type 1, type 3, K14, and MC12 and their interaction with L-cysteine have been studied by ultraviolet photoelectron spectroscopy with synchrotron radiation. It was found that the electronic structures of the type-1 and type-3 dental alloys are similar to that of polycrystalline Au, while that of the K14 dental alloy is much affected by Cu. The electronic states of the MC12 dental alloy originate dominantly from Cu 3d states and Pd 4d states around the top of the valence bands, while the 4∼7-eV electronic structure of MC12 originates from the Ag 4d states. The peak shift and the change in shape due to alloying are observed in all the dental alloys. For the L-cysteine thin films, new peak or structure observed around 2 eV on all the dental alloys is suggested to be due to the bonding of S 3sp orbitals with the dental alloy surfaces. The Cu-S bond as well as the Au-S and Au-O bonds may cause the change in the electronic structure of the L-cysteine on type 1, type 3 and K14. For MC12, the interaction with L-cysteine may be dominantly due to the Pd-S, Cu-S, and Ag-O bonds, while the contribution of the Ag-S bond is small.

  2. Summary of structural refinement in hi-silicon aluminium piston alloy with phosphorous as grain refiner

    International Nuclear Information System (INIS)

    Malik, F.A.; Sheikh, S.T.; Choudhry, A.A.

    2003-01-01

    Aluminium Silicon Alloys are extensively used in a wide variety of applications. There are numerous variables in composition, production control, final structure which can influence the mechanical properties of Hi - Silicon Piston alloys. Hypereutectic AlSi alloys develop coarse grain primary silicon crystals, which have a strong negative effect on the tensile strength, the ductility, and the hardness. These crystals slow machining and reduce the tool life considerably. Phosphorous addition produce a fine, evenly spread crystal structure, lamellar structure of the silicon changes into a granular structure. (author)

  3. Effect of Iron and Magnesium on Alloy AL9M Structure and Properties

    Science.gov (United States)

    Bazhenov, V. E.; Koltygin, A. V.; Belov, V. D.

    2017-09-01

    The effect of iron impurity on the structure and properties of aluminum alloy AL9M, especially its action on magnesium distribution within the structure, is studied. The microstructure of a cast component of this alloy broken during operation is analyzed. It is shown that iron impurity has an unfavorable effect on structure and mechanical properties of a casting due to appearance of Al9Fe2Si and Al18Fe2Mg7Si10 intermetallics. Formation of these intermetallics consumes a considerable amount of magnesium and lowers the content of the Q(Al5Cu2Mg8Si6) strengthening phase in the alloy structure.

  4. Prospects for zirconium structural alloys at high temperatures

    International Nuclear Information System (INIS)

    Thomas, W.R.

    1969-05-01

    Improved station efficiencies and lower capital costs provide incentives for the development of zirconium alloys for pressure tubes which can operate at temperatures above 450 o C. The experience of the Ti industry indicates that a complex alloy containing solution hardeners of Sn or Al and precipitation hardeners of Mo and Nb and perhaps Si will be required. The thermal neutron cross-section of the alloy will be about 10% higher than Zircaloy-2 and because of its poor corrosion resistance will require cladding with a corrosion resistant alloy such as Zr-Cr. Results to date indicate that such a pressure tube is feasible. (author)

  5. The Age-Precipitations Structure Of Al-Mg-Ge Alloy Aged At 473K

    Directory of Open Access Journals (Sweden)

    Kawai A.

    2015-06-01

    Full Text Available The Al-Mg-Ge alloy is one of the age-hardening aluminum alloy after solution heat treatment. It has been proposed that the age-precipitation behavior of Al-Mg-Ge alloy is different from that of Al-Mg-Si alloy according to our previous works about the microstructure on Al-Mg-Ge alloy over-aged at 523K. For example, The hardness of peak aged Al-1.0mass%Mg2Ge alloy is higher than that of Al-1.0mass%Mg2Si alloy. The precipitates in the over-aged samples have been classified as some metastable phases, such as the β’-phase and Type-A precipitates and equilibrium phase of β-Mg2Ge by TEM observation. There a few reports about microstructure on Al-Mg-Ge alloys observed by TEM for different aging times. The age-precipitations structure of Al-Mg-Ge alloy has not been became clear. In this work, TEM observation was investigated the microstructure on Al-1.0mass%Mg2Ge alloy for difference aging times aged at 473K.

  6. Investigation on mechanical alloying process for v-cr-ti alloys

    International Nuclear Information System (INIS)

    Stanciulescu, M.; Carlan, P.; Mihalache, M.; Bucsa, G.; Abrudeanu, M.; Galateanu, A.

    2015-01-01

    Mechanical alloying (MA) is an efficient approach for fabricating oxide-dispersion alloys and structural materials including vanadium alloys for fusion and fission application. Dissolution behaviour of the alloying elements is a key issue for optimizing the mechanical alloying process in fabricating vanadium alloys. This paper studies the MA process of V-4wt.%Cr-4wt.%Ti alloy. The outcomes of the MA powders in a planetary ball mill are reported in terms of powder particle size and morphology evolution and elemental composition. The impact of spark-plasma sintering process on the mechanically alloyed powder is analysed. An optimal set of sintering parameters, including the maximum temperature, the dwell time and the heating rate are determined. (authors)

  7. Formation and structure of nanocrystalline Al-Mn-Ni-Cu alloys

    International Nuclear Information System (INIS)

    Latuch, J.; Krasnowski, M.; Ciesielska, B.

    2002-01-01

    This paper reports the results of the short investigation on the effect of Cu additions upon the nanocrystallization behaviour of an Al-Mn-Ni alloy. 2 at.% Cu added to the base alloy of Al 85 Mn 10 Ni 5 alloy by substitution for Mn(mischmetal). The control of cooling rate did not cause the formation of nanocrystals of fcc-Al phase. The nanocrystalline structure fcc-Al + amorphous phase in quarternary alloy was obtained by isothermal annealing and continuous heating method, but the last technique is more effective. The volume fraction, lattice parameter, and size of Al-phase were calculated. (author)

  8. Structure of tetragonal martensite in the In95.42Cd4.58 cast alloy

    Science.gov (United States)

    Khlebnikova, Yu. V.; Egorova, L. Yu.; Rodionov, D. P.; Kazantsev, V. A.

    2017-11-01

    The structure of martensite in the In95.42Cd4.58 alloy has been studied by metallography, X-ray diffraction, dilatometry, and transmission electron microscopy. It has been shown that a massive structure built of colonies of tetragonal lamellar plates divided by a twin boundary {101}FCT is formed in the alloy under cooling below the martensite FCC → FCT transition temperature. The alloy recrystallizes after a cycle of FCT → FCC → FCT transitions with a decrease in the grain size by several times compared with the initial structure such fashion that the size of massifs and individual martensite lamella in the massif correlates with the change in the size of the alloy grain. Using thermal cycling, it has been revealed that the alloy tends to stabilize the high-temperature phase.

  9. Damping Properties vs. Structure Fineness of the High-zinc Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    W.K. Krajewski

    2012-09-01

    Full Text Available The subject of this study is the presentation of relation between the degree of structure fineness and ultrasonic wave dampingcoefficient for the high-zinc aluminium alloys represented in this study by the sand mould cast alloy Al - 20 wt% Zn (AlZn20. Thestudied alloy was refined with a modifying (Al,Zn-Ti3 ternary master alloy, introducing Ti in the amount of 400 pm into metal. Based on the analysis of the initial and modified alloy macrostructure images and ultrasonic testing, it was found that the addition of (Al,Zn-Ti3 master alloy, alongside a significant fragmentation of grains, does not reduce the coefficient of ultrasonic waves with a frequency of 1 MHz.

  10. Electronic structures of the L-cysteine film on dental alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, K., E-mail: e7141@cc.saga-u.ac.jp [Synchrotron Light Application Center, Saga University, Saga 840-8502 (Japan); Tsujibayashi, T. [Department of Physics, Osaka Dental University, Osaka 573-1121 (Japan); Takahashi, K.; Azuma, J. [Synchrotron Light Application Center, Saga University, Saga 840-8502 (Japan); Kakimoto, K. [Department of Geriatric Dentistry, Osaka Dental University, Osaka 573-1121 (Japan); Kamada, M. [Synchrotron Light Application Center, Saga University, Saga 840-8502 (Japan)

    2011-04-15

    Research highlights: {yields} The electronic structures of dental alloys and L-cysteine film were studied by PES. {yields} The density of states in the dental alloy originates from Au and Cu as constituents. {yields} The Cu-3d states contribute dominantly to the occupied states near the Fermi level. {yields} The electronic structure of L-cysteine thin film is different from the thick film. {yields} The bonding between Cu-3d and S-3sp states are formed at the interface. - Abstract: Metal-organic interfaces have been attracting continuous attention in many fields including basic biosciences. The surface of dental alloys could be one of such interfaces since they are used in a circumstance full of organic compounds such as proteins and bacteria. In this work, electronic structures of Au-dominant dental alloys, which have Ag and Cu besides Au, and those of L-cysteine on the dental alloys have been studied by photoelectron spectroscopy with synchrotron radiation. It was found that the density of states in the dental alloy originate from gold and copper as constituents, and the Cu-3d states contribute dominantly to the occupied states near the Fermi level. It was also found that the electronic structure of the L-cysteine thin film on the dental alloy is different from that of the L-cysteine thick film. The result indicates the formation of the orbital bonding between Cu-3d and S-3sp states in the thin film on the dental alloy.

  11. Electronic structures of the L-cysteine film on dental alloys

    International Nuclear Information System (INIS)

    Ogawa, K.; Tsujibayashi, T.; Takahashi, K.; Azuma, J.; Kakimoto, K.; Kamada, M.

    2011-01-01

    Research highlights: → The electronic structures of dental alloys and L-cysteine film were studied by PES. → The density of states in the dental alloy originates from Au and Cu as constituents. → The Cu-3d states contribute dominantly to the occupied states near the Fermi level. → The electronic structure of L-cysteine thin film is different from the thick film. → The bonding between Cu-3d and S-3sp states are formed at the interface. - Abstract: Metal-organic interfaces have been attracting continuous attention in many fields including basic biosciences. The surface of dental alloys could be one of such interfaces since they are used in a circumstance full of organic compounds such as proteins and bacteria. In this work, electronic structures of Au-dominant dental alloys, which have Ag and Cu besides Au, and those of L-cysteine on the dental alloys have been studied by photoelectron spectroscopy with synchrotron radiation. It was found that the density of states in the dental alloy originate from gold and copper as constituents, and the Cu-3d states contribute dominantly to the occupied states near the Fermi level. It was also found that the electronic structure of the L-cysteine thin film on the dental alloy is different from that of the L-cysteine thick film. The result indicates the formation of the orbital bonding between Cu-3d and S-3sp states in the thin film on the dental alloy.

  12. A Study of Phase Composition and Structure of Alloys of the Al - Mg - Si - Fe System

    Science.gov (United States)

    Mailybaeva, A. D.; Zolotorevskii, V. S.; Smagulov, D. U.; Islamkulov, K. M.

    2017-03-01

    The Thermo-Calc software is used to compute the phase transformations occurring during cooling of alloys. Polythermal and isothermal sections of the phase diagram of the Al - Mg - Si - Fe system are plotted. The phase composition and the structure of aluminum alloys in cast condition and after a heat treatment are studied experimentally.

  13. Structure and mechanical properties of nanostructured Al-0.3%Cu alloy

    DEFF Research Database (Denmark)

    Wakeel, Aneela; Huang, Tianlin; Wu, Guilin

    2014-01-01

    An Al-0.3%Cu alloy has been produced using extremely high purity (99.9996%) Al and OFHC Cu.The alloy was cold rolled to 98% thickness reduction, forming a stable lamellar structure that has a lamellar boundary spacing of about 200nm and a tensile strength of 225MPa. During recovery annealing at t...

  14. The influence of chemical composition on the properties and structure Al-Si-Cu(Mg alloys

    Directory of Open Access Journals (Sweden)

    M. Kaczorowski

    2007-04-01

    Full Text Available The mechanical properties of different chemical composition AlSiCuMg type cast alloys after precipitation hardening are presented. The aim of the study was to find out how much the changes in chemistry of aluminum cast alloys permissible by EN-PN standards may influence the mechanical properties of these alloys. Eight AlSi5Cu3(Mg type cast alloys of different content alloying elements were selected for the study. The specimens cut form test castings were subjected to precipitation hardening heat treatment. The age hardened specimens were evaluated using tensile test, hardness measurements and impact test. Moreover, the structure investigation were carried out using either conventional light Metallography and scanning (SEM and transmission (TEM electron microscopy. The two last methods were used for fractography observations and precipitation process observations respectively. It was concluded that the changes in chemical composition which can reach even 2,5wt.% cause essential differences of the structure and mechanical properties of the alloys. As followed from quantitative evaluation and as could be predicted theoretically, copper and silicon mostly influenced the mechanical properties of AlSi5Cu3(Mg type cast alloys. Moreover it was showed that the total concentration of alloying elements accelerated and intensifies the process of decomposition of supersaturated solid solution. The increase of Cu and Mg concentration increased the density of precipitates. It increases of strength properties of the alloys which are accompanied with decreasing in ductility.

  15. Corrosion and oxidation of vanadium-base alloys

    International Nuclear Information System (INIS)

    Loomis, B.A.; Wiggins, G.

    1983-10-01

    The corrosion of several V-base alloys on exposure at elevated temperatures to helium environments containing hydrogen and/or water vapor are presented. These results are utilized to discuss the consequences of the selection of certain radiation-damage resistant, V-base alloys for structural materials applications in a fusion reactor

  16. Effect of structure and alloying elements on void formation in austenitic steels and nickel alloys

    International Nuclear Information System (INIS)

    Levy, V.; Azam, N.; Le Naour, L.; Didout, G.; Delaplace, J.

    1977-01-01

    In the development of the fast breeder reactors the phenomenon of metal swelling due to the formation of radiation induced voids is a large problem. In the complex alloys small fluctuations in composition can have a considerable effect on swelling and a great deal of investigation on the effect of both major and minor alloying elements is needed to be able to predict swelling. To provide more insight a research program involving irradiation of both commercial or specially cast alloys by 500 keV Ni + ions or 1 MeV electrons has been developed. The major results are presented

  17. Structural basis of influenza virus fusion inhibition by the antiviral drug Arbidol

    Energy Technology Data Exchange (ETDEWEB)

    Kadam, Rameshwar U.; Wilson, Ian A.

    2016-12-21

    The broad-spectrum antiviral drug Arbidol shows efficacy against influenza viruses by targeting the hemagglutinin (HA) fusion machinery. However, the structural basis of the mechanism underlying fusion inhibition by Arbidol has remained obscure, thereby hindering its further development as a specific and optimized influenza therapeutic. We determined crystal structures of Arbidol in complex with influenza virus HA from pandemic 1968 H3N2 and recent 2013 H7N9 viruses. Arbidol binds in a hydrophobic cavity in the HA trimer stem at the interface between two protomers. This cavity is distal to the conserved epitope targeted by broadly neutralizing stem antibodies and is ~16 Å from the fusion peptide. Arbidol primarily makes hydrophobic interactions with the binding site but also induces some conformational rearrangements to form a network of inter- and intraprotomer salt bridges. By functioning as molecular glue, Arbidol stabilizes the prefusion conformation of HA that inhibits the large conformational rearrangements associated with membrane fusion in the low pH of the endosome. This unique binding mode compared with the small-molecule inhibitors of other class I fusion proteins enhances our understanding of how small molecules can function as fusion inhibitors and guides the development of broad-spectrum therapeutics against influenza virus.

  18. Fusion and characterization of an alloy Cu-Zn-Al-Ni of nuclear interest; Fusion y caracterizacion de una aleacion Cu-Zn-Al-Ni de interes nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Santana M, J.S

    2003-07-01

    The present work is the result of the study of a non ferrous quatenary alloy of Cu-Zn-Al-Ni (Foundry 3), it was chosen of a series of alloys to obtain so much information of its microstructural properties like mechanical, evaluating them and comparing them with the previously obtained ternary alloys of Cu-AI-Ni (Foundry 1) and Cu-Zn-AI (Foundry 2) identified as alloys of memory effect and superalloys. These were carried out starting from the foundry of their pure elements of Cu, Zn, Al, Ni. When physically having the ingot of each alloy, different techniques were used for their characterization. The used techniques were through the metallographic analysis, by scanning electron microscopy (SEM), X-ray dispersive energy spectroscopy (EDS), X-ray diffraction (XRD), mechanical essays and Rockwell hardness. The non ferrous quaternary alloy Cu-Zn-AI-Ni by means of the metallographic analysis didn't show significant differences in their three sections (superficial, longitudinal and transverse) since result an homogeneous alloy at the same that the both ternaries. The grain size of the quaternary alloy is the finest while the ternary alloy of Cu-AI-Ni is the one that obtained the biggest grain size. Through MEB together with the analysis by EDS and the mapping of the elements that constitute each alloy, show that the three foundries were alloyed, moreover the presence of aggregates was also observed in the Foundries 2 and 3. These results by means of the analysis of XRD corroborate that these alloys have more of two elements. Relating the microstructural properties with those mechanical show us that as minor was the grain size, better they were his mechanical properties, in this case that of the quaternary alloy. With regard to the test of Rockwell hardness the Foundry 1 were the softest with the temper treatment, while that the Foundries 2 and 3 were the hardest with this same treatment, being still harder the Foundry 2 but with very little difference, for what great

  19. Highlighting micrographic structures of uranium-zirconium alloys with 6 per cent of weight of Zr

    International Nuclear Information System (INIS)

    Bouleau, Maurice

    1961-01-01

    In order to study the transformation kinetics of U-Zr alloys with a Zr content of 6 per cent in weight, the authors searched for a slow enough electrolytic polishing bath, and for an attack and examination method to highlight martensite structures produced by austempering and water tempering, and ultra-fine decomposition structures obtained by austempering. The authors explain the choice of a perchloric-butyl glycol polishing bath, of an examination under polarized light or normal light after appropriate attacks. These studies are reported for annealed alloys, and for processed alloys with martensite or ultra-fine decomposition structures [fr

  20. On the atomic structure of liquid Ni-Si alloys: a neutron diffraction study

    Science.gov (United States)

    Gruner, S.; Marczinke, J.; Hennet, L.; Hoyer, W.; Cuello, G. J.

    2009-09-01

    The atomic structure of the liquid NiSi and NiSi2 alloys is investigated by means of neutron diffraction experiments with isotopic substitution. From experimental data-sets obtained using four Ni isotopes, partial structure factors and pair correlation functions are obtained by applying a reverse Monte Carlo modelling approach. Both alloys were found to exhibit a strong tendency to hetero-coordination within the first coordination shell. In particular, covalent Si-Si bonds with somewhat greater distances seem to influence the structure of the liquid NiSi alloy.

  1. On the atomic structure of liquid Ni-Si alloys: a neutron diffraction study

    Energy Technology Data Exchange (ETDEWEB)

    Gruner, S; Marczinke, J; Hoyer, W [Institute of Physics, Chemnitz University of Technology, D-09107 Chemnitz (Germany); Hennet, L [CNRS-CEMHTI, University of Orleans, F-45071 Orleans (France); Cuello, G J, E-mail: sascha.gruner@physik.tu-chemnitz.d [Institute Laue-Langevin, PO Box 156, F-38042 Grenoble (France)

    2009-09-23

    The atomic structure of the liquid NiSi and NiSi{sub 2} alloys is investigated by means of neutron diffraction experiments with isotopic substitution. From experimental data-sets obtained using four Ni isotopes, partial structure factors and pair correlation functions are obtained by applying a reverse Monte Carlo modelling approach. Both alloys were found to exhibit a strong tendency to hetero-coordination within the first coordination shell. In particular, covalent Si-Si bonds with somewhat greater distances seem to influence the structure of the liquid NiSi alloy.

  2. Development of materials of low activation for nuclear fusion

    International Nuclear Information System (INIS)

    Kamata, Koji

    1986-01-01

    Unlike nuclear fission, in nuclear fusion, it is a feature that activated products are not formed, but this merit is to be lost if the structural materials of the equipment are activated by generated neutrons. Accordingly, the elements which are activated by neutrons must be excluded from the structural materials in nuclear fusion reactors and fusion experiment apparatuses. As the result of evaluating the materials for low induced activation, aluminum alloys are the most promising. Aluminum alloys have also excellent properties in gas release, the thermal stress of first walls due to the temperature distribution, vaporizing quantity at the time of disruption and so on. However, in the existing aluminum alloys, the lowering of strength above 150 deg C is remarkable, and when the aluminum walls of vacuum vessels are too thick, the rate of tritium breeding may lower. The Institute of Plasma Physics, Nagoya University, carried out the total design of a tokamak made of an aluminum alloy for the first time in the world. In this paper, the properties of the aluminum alloy and the feasibility of its industrial manufacture are described, and the course of improving this alloy is pointed out. Improved 5083 alloy and Al-4 % Mg-1 % Li alloy were investigated. The industrial manufacture of large plates with this Al-Mg-Li alloy is possible now. (Kako, I.)

  3. Structure and radiation induced swelling of steels and alloys

    International Nuclear Information System (INIS)

    Parshin, A.M.

    1983-01-01

    Regularities of vacancy void formation and radiation induced swelling of austenitic chromium-nickel steels and alloyse ferritic steels as well as titanium α-alloys under radiation by light and heavy ions and neutrons are considered. Possible methods for preparation of alloys with increased resistance to radiation swelling are described. Accounting for investigations into ferritic steels and α-alloys of titanium the basic way of weakening vacancy smelling is development of continuous homogeneous decomposition of solid solution using alloying with vividly expressed incubation period at a certain volumetric dilatation as well as decompositions of the type of ordering, K-state, lamination of solid solutions, etc. Additional alloying of solid solutions is also shown to be necessary for increasing recrystallization temperature of cold-deformed steel

  4. Strength properties and structure of a submicrocrystalline Al-Mg-Mn alloy under shock compression

    Science.gov (United States)

    Petrova, A. N.; Brodova, I. G.; Razorenov, S. V.

    2017-06-01

    The results of studying the strength of a submicrocrystalline aluminum A5083 alloy (chemical composition was 4.4Mg-0.6Mn-0.11Si-0.23Fe-0.03Cr-0.02Cu-0.06Ti wt % and Al base) under shockwave compression are presented. The submicrocrystalline structure of the alloy was produced in the process of dynamic channel-angular pressing at a strain rate of 104 s-1. The average size of crystallites in the alloy was 180-460 nm. Hugoniot elastic limit σHEL, dynamic yield stress σy, and the spall strength σSP of the submicrocrystalline alloy were determined based on the free-surface velocity profiles of samples during shock compression. It has been established that upon shock compression, the σHEL and σy of the submicrocrystalline alloy are higher than those of the coarse-grained alloy and σsp does not depend on the grain size. The maximum value of σHEL reached for the submicrocrystalline alloy is 0.66 GPa, which is greater than that in the coarse-crystalline alloy by 78%. The dynamic yield stress is σy = 0.31 GPa, which is higher than that of the coarse-crystalline alloy by 63%. The spall strength is σsp = 1.49 GPa. The evolution of the submicrocrystalline structure of the alloy during shock compression was studied. It has been established that a mixed nonequilibrium grain-subgrain structure with a fragment size of about 400 nm is retained after shock compression, and the dislocation density and the hardness of the alloy are increased.

  5. Structural characteristics and elevated temperature mechanical properties of AJ62 Mg alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kubásek, J., E-mail: Jiri.Kubasek@vscht.cz; Vojtěch, D.; Martínek, M.

    2013-12-15

    Structure and mechanical properties of the novel casting AJ62 (Mg–6Al–2Sr) alloy developed for elevated temperature applications were studied. The AJ62 alloy was compared to commercial casting AZ91 (Mg–9Al–1Zn) and WE43 (Mg–4Y–3RE) alloys. The structure was examined by scanning electron microscopy, x-ray diffraction and energy dispersive spectrometry. Mechanical properties were characterized by Viskers hardness measurements in the as-cast state and after a long-term heat treatment at 250 °C/150 hours. Compressive mechanical tests were also carried out both at room and elevated temperatures. Compressive creep tests were conducted at a temperature of 250 °C and compressive stresses of 60, 100 and 140 MPa. The structure of the AJ62 alloy consisted of primary α-Mg dendrites and interdendritic nework of the Al{sub 4}Sr and massive Al{sub 3}Mg{sub 13}Sr phases. By increasing the cooling rate during solidification from 10 and 120 K/s the average dendrite arm thickness decreased from 18 to 5 μm and the total volume fraction of the interdendritic phases from 20% to 30%. Both factors slightly increased hardness and compressive strength. The room temperature compressive strength and hardness of the alloy solidified at 30 K/s were 298 MPa and 50 HV 5, i.e. similar to those of the as-cast WE43 alloy and lower than those of the AZ91 alloy. At 250 °C the compressive strength of the AJ62 alloy decreased by 50 MPa, whereas those of the AZ91 and WE43 alloys by 100 and 20 MPa, respectively. The creep rate of the AJ62 alloy was higher than that of the WE43 alloy, but significantly lower in comparison with the AZ91 alloy. Different thermal stabilities of the alloys were discussed and related to structural changes during elevated temperature expositions. - Highlights: • Small effect of cooling rate on the compressive strength and hardness of AJ 62 • A bit lower compressive strength of AJ 62 compared to AZ91 at room temperature • Higher resistance of the AJ 62

  6. Constitution, structure and magnetic properties of some rare-earth - cobalt-aluminium alloys

    International Nuclear Information System (INIS)

    Evans, J.; Harris, I.R.

    1982-01-01

    The constitution and structure of the alloys represented by the formulae Cesub(1-x)Alsub(x)Co 5 and Prsub(1-x)Alsub(x)Co 5 (where 0 = 5 produces a mixture of the 1:5 and 2:17 phases based on CeCo 5 and Ce 2 Co 17 ; there are two variations of the 2:17 phase which are isostructural with the hexagonal Th 2 Ni 17 -type and rhombohedral Th 2 Zn 17 -type phases. At the composition Cesub(0.76)Alsub(0.24)Co 5 (4 at % Al) the alloy consists only of the 2:17-type phases and metallographically the alloy is one phase in appearance. Further substitution of Al results in the precipitation of an fcc phase, based on the Co-Al solid solution, in the 2:17 matrix. The crystal structures of the Prsub(1-x)Alsub(x)Co 5 alloys are very similar to those of the equivalent cerium alloys. The metallographic structures of the Pr alloys in the composition range 1 to 3 at % Al show significant differences from the corresponding Ce alloys. Determination of the Curie temperatures of the Rsub(1-x)Alsub(x)Co 5 alloys (R = Ce and Pr) in the composition range 0 = 5 and PrCo 5 phases. (author)

  7. The effect of fusion-relevant helium levels on the mechanical properties of isotopically tailored ferritic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hankin, G.L. [Loughborough Univ. (United Kingdom); Hamilton, M.L.; Gelles, D.S. [Pacific Northwest National Lab., Richland, WA (United States)] [and others

    1997-04-01

    The yield and maximum strengths of an irradiated series of isotopically tailored ferritic alloys were evaluated using the shear punch test. The composition of three of the alloys was Fe-12Cr-1.5Ni. Different balances of nickel isotopes were used in each alloy in order to produce different helium levels. A fourth alloy, which contained no nickel, was also irradiated. The addition of nickel at any isotopic balance to the Fe-12Cr base alloy significantly increased the shear yield and maximum strengths of the alloys, and as expected, the strength of the alloys decreased with increasing irradiation temperature. Helium itself, up to 75 appm over 7 dpa appears to have little effect on the mechanical properties of the alloys.

  8. Prospects for designing structural cast eutectic alloys on Al-Ce-Ni system base

    International Nuclear Information System (INIS)

    Belov, N.A.; Naumova, E.S.

    1996-01-01

    The phase diagram of Al-Ce-Ni system is built for an aluminium corner at component concentration up to 16 mass %Ce and 8 mass%Ni. A ternary eutectic reaction is established at 12%Ce, 5%Ni and 626 deg C. The ternary eutectic alloy is similar in structure to rapidly cooled Al base alloys with transition metals. The possibility to design new cast alloys based on three-phase (Al)+NiAl 3 +CeAl 4 eutectics is under consideration. Al-Zn-Mg-Cu, Al-Sc and Al-Zr base alloys can be used as (Al) constituent of the eutectics. The new alloys may be considered as heat resistant ones due to the fact that no structural changes are observed in castings on heating up to 350 deg C. 18 refs.; 4 figs.; 2 tabs

  9. Crystal Structural Effect of AuCu Alloy Nanoparticles on Catalytic CO Oxidation

    International Nuclear Information System (INIS)

    Zhan, Wangcheng; Wang, Jinglin; Wang, Haifeng; Zhang, Jinshui; Liu, Xiaofei

    2017-01-01

    Controlling the physical and chemical properties of alloy nanoparticles (NPs) is an important approach to optimize NP catalysis. Unlike other tuning knobs, such as size, shape, and composition, crystal structure has received limited attention and not been well understood for its role in catalysis. This deficiency is mainly due to the difficulty in synthesis and fine-tuning of the NPs’ crystal structure. Here, Exemplifying by AuCu alloy NPs with face centered cubic (fcc) and face centered tetragonal (fct) structure, we demonstrate a remarkable difference in phase segregation and catalytic performance depending on the crystal structure. During the thermal treatment in air, the Cu component in fcc-AuCu alloy NPs segregates more easily onto the alloy surface as compared to that in fct-AuCu alloy NPs. As a result, after annealing at 250 °C in air for 1 h, the fcc- and fct-AuCu alloy NPs are phase transferred into Au/CuO and AuCu/CuO core/shell structures, respectively. More importantly, this variation in heterostructures introduces a significant difference in CO adsorption on two catalysts, leading to a largely enhanced catalytic activity of AuCu/CuO NP catalyst for CO oxidation. Furthermore, the same concept can be extended to other alloy NPs, making it possible to fine-tune NP catalysis for many different chemical reactions.

  10. Crystal Structural Effect of AuCu Alloy Nanoparticles on Catalytic CO Oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Zhan, Wangcheng [East China Univ. of Science and Technology, Shanghai (China); Wang, Jinglin [East China Univ. of Science and Technology, Shanghai (China); Wang, Haifeng [East China Univ. of Science and Technology, Shanghai (China); Zhang, Jinshui [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Liu, Xiaofei [East China Univ. of Science and Technology, Shanghai (China); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Zhang, Pengfei [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Chi, Miaofang [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Guo, Yanglong [East China Univ. of Science and Technology, Shanghai (China); Guo, Yun [East China Univ. of Science and Technology, Shanghai (China); Lu, Guanzhong [East China Univ. of Science and Technology, Shanghai (China); Sun, Shouheng [Brown Univ., Providence, RI (United States); Dai, Sheng [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States); Zhu, Huiyuan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-06-07

    Controlling the physical and chemical properties of alloy nanoparticles (NPs) is an important approach to optimize NP catalysis. Unlike other tuning knobs, such as size, shape, and composition, crystal structure has received limited attention and not been well understood for its role in catalysis. This deficiency is mainly due to the difficulty in synthesis and fine-tuning of the NPs’ crystal structure. Here, Exemplifying by AuCu alloy NPs with face centered cubic (fcc) and face centered tetragonal (fct) structure, we demonstrate a remarkable difference in phase segregation and catalytic performance depending on the crystal structure. During the thermal treatment in air, the Cu component in fcc-AuCu alloy NPs segregates more easily onto the alloy surface as compared to that in fct-AuCu alloy NPs. As a result, after annealing at 250 °C in air for 1 h, the fcc- and fct-AuCu alloy NPs are phase transferred into Au/CuO and AuCu/CuO core/shell structures, respectively. More importantly, this variation in heterostructures introduces a significant difference in CO adsorption on two catalysts, leading to a largely enhanced catalytic activity of AuCu/CuO NP catalyst for CO oxidation. Furthermore, the same concept can be extended to other alloy NPs, making it possible to fine-tune NP catalysis for many different chemical reactions.

  11. New ternary ordered structures in CuMPt6 (M=3d elements) alloys

    International Nuclear Information System (INIS)

    Das, Ananda Kumar; Nakamura, Reo; Takahashi, Miwako; Ohshima, Ken-ichi; Iwasaki, Hiroshi; Shishido, Toetsu

    2006-01-01

    X-ray and electron diffraction measurements were performed to investigate the structure and ordering behaviour of the ternary alloys CuMPt 6 (M=Ti, V, Cr, Mn, Fe, Co, and Ni). X-ray polycrystalline diffraction patterns of all the speciments quenched from 1000degC have shown that a single phase is formed at this stoichiometric composition. The alloys with M=Cr, Mn, Co, and Ni have the face-centred cubic (fcc) structure, while in the alloys with M=Ti, V, and Fe ordering has occurred and the structure is of the Cu 3 Au type. On annealing at lower temperatures ordering has been induced in the alloys with M=Cr, Mn, and Co and the structure is of the Cu 3 Au type, though the ordering in the last alloy has remained incomplete. Detailed X-ray diffraction measurements on single crystals of the CuMnPt 6 alloy have revealed that further ordering takes place and structure changes from the Cu 3 Au type into the cubic ABC 6 type with the unit cell as large 2 x 2 x 2 as the fcc unit cell, a new observation of the double-step ordering in the ternary fcc alloy. The corresponding transition temperatures are T c =970(±5)degC and T cl =750(±5)degC. (author)

  12. Smart alloys for a future fusion power plant: First studies under stationary plasma load and in accidental conditions

    Directory of Open Access Journals (Sweden)

    A. Litnovsky

    2017-08-01

    Plasma exposure was followed by the oxidation of alloys at 1000°C accomplishing the first test of these new materials both in a plasma environment and under accidental conditions. Compared to pure tungsten, smart alloys featured the 3-fold suppression of oxidation. Plasma exposure did not affect the oxidation resistance of smart alloys. At the same time, the self-passivation of the protective layer did not occur, calling for further optimization of alloys.

  13. Structure, mechanical properties, and grindability of dental Ti-Zr alloys.

    Science.gov (United States)

    Ho, Wen-Fu; Chen, Wei-Kai; Wu, Shih-Ching; Hsu, Hsueh-Chuan

    2008-10-01

    Structure, mechanical properties and grindability of a series of binary Ti-Zr alloys with zirconium contents ranging from 10 to 40 wt% have been investigated. Commercially pure titanium (c.p. Ti) was used as a control. Experimental results indicated that the diffraction peaks of all the Ti-Zr alloys matched those for alpha Ti. No beta-phase peaks were found. The hardness of the Ti-Zr alloys increased as the Zr contents increased, and ranged from 266 HV (Ti-10Zr) to 350 HV (Ti-40Zr). As the concentration of zirconium in the alloys increased, the strength, elastic recovery angles and hardness increased. Moreover, the elastically recoverable angle of Ti-40Zr was higher than of c.p. Ti by as much as 550%. The grindability of each metal was found to be largely dependent on the grinding conditions. The Ti-40Zr alloy had a higher grinding rate and grinding ratio than c.p. Ti at low speed. The grinding rate of the Ti-40Zr alloy at 500 m/min was about 1.8 times larger than that of c.p. Ti, and the grinding ratio was about 1.6 times larger than that of c.p. Ti. Our research suggested that the Ti-40Zr alloy has better mechanical properties, excellent elastic recovery capability and improved grindability at low grinding speed. The Ti-40Zr alloy has a great potential for use as a dental machining alloy.

  14. Sheath structure in negative ion sources for fusion (invited)

    International Nuclear Information System (INIS)

    McAdams, R.; King, D. B.; Surrey, E.; Holmes, A. J. T.

    2012-01-01

    In fusion negative ion sources, the negative ions are formed on the caesiated plasma grid predominantly by hydrogen atoms from the plasma. The space charge of the negative ions leaving the wall is not fully compensated by incoming positive ions and at high enough emission a virtual cathode is formed. This virtual cathode limits the flux of negative ions transported across the sheath to the plasma. A 1D collisionless model of the sheath is presented taking into account the virtual cathode. The model will be applied to examples of the ion source operation. Extension of the model to the bulk plasma shows good agreement with experimental data. A possible role for fast ions is discussed.

  15. Osteoclast Fusion

    DEFF Research Database (Denmark)

    Marie Julie Møller, Anaïs; Delaissé, Jean-Marie; Søe, Kent

    2017-01-01

    on the nuclearity of fusion partners. While CD47 promotes cell fusions involving mono-nucleated pre-osteoclasts, syncytin-1 promotes fusion of two multi-nucleated osteoclasts, but also reduces the number of fusions between mono-nucleated pre-osteoclasts. Furthermore, CD47 seems to mediate fusion mostly through...... individual fusion events using time-lapse and antagonists of CD47 and syncytin-1. All time-lapse recordings have been studied by two independent observers. A total of 1808 fusion events were analyzed. The present study shows that CD47 and syncytin-1 have different roles in osteoclast fusion depending...... broad contact surfaces between the partners' cell membrane while syncytin-1 mediate fusion through phagocytic-cup like structure. J. Cell. Physiol. 9999: 1-8, 2016. © 2016 Wiley Periodicals, Inc....

  16. Towards a reduced activation structural materials database for fusion DEMO reactors

    International Nuclear Information System (INIS)

    Moeslang, A.; Diegele, E.; Laesser, R.; Klimiankou, M.; Lindau, R.; Materna-Morris, E.; Rieth, M.; Lucon, E.; Petersen, C.; Schneider, H.-C.; Pippan, R.; Rensman, J.W.; Schaaf, B. van der; Tavassoli, F.

    2005-01-01

    The development of First Wall, Blanket and Divertor materials which are capable of withstanding many years the high neutron and heat fluxes, is a critical path to fusion power. Therefore, the timely availability of a sound materials database has become an indispensable element in international fusion road maps. In order to provide materials design data for short term needs of ITER Test Blanket Modules and for a DEMOnstration fusion reactor, a wealth of R and D results on the European reduced activation ferritic-martensitic steel EUROFER, and on oxide dispersion strengthened variants are being characterized, mainly in the temperature window 250-650 deg. C. The characterisation includes irradiations up to 15 dpa in the mixed spectrum reactor HFR and up to 75 dpa in the fast breeder reactor BOR60. Industrial EUROFER-batches of 3.5 and 7.5 tons have been produced with a variety of semi-finished, quality-assured product forms. To increase thermal efficiency of blankets, high temperature resistant SiC f /SiC channel inserts for liquid metal coolant tubes are also developed. Regarding radiation damage resistance, a broad based reactor irradiation programs counts several steps from ≤5dpa (ITER TBMs) up to 75 dpa (DEMO). For the European divertor designers, a materials data base is presently being set up for pure W and W alloys, and related reactor irradiations are foreseen with temperatures from 650-1000 deg. C. (author)

  17. Exploration and Development of High Entropy Alloys for Structural Applications

    Directory of Open Access Journals (Sweden)

    Daniel B. Miracle

    2014-01-01

    Full Text Available We develop a strategy to design and evaluate high-entropy alloys (HEAs for structural use in the transportation and energy industries. We give HEA goal properties for low (≤150 °C, medium (≤450 °C and high (≥1,100 °C use temperatures. A systematic design approach uses palettes of elements chosen to meet target properties of each HEA family and gives methods to build HEAs from these palettes. We show that intermetallic phases are consistent with HEA definitions, and the strategy developed here includes both single-phase, solid solution HEAs and HEAs with intentional addition of a 2nd phase for particulate hardening. A thermodynamic estimate of the effectiveness of configurational entropy to suppress or delay compound formation is given. A 3-stage approach is given to systematically screen and evaluate a vast number of HEAs by integrating high-throughput computations and experiments. CALPHAD methods are used to predict phase equilibria, and high-throughput experiments on materials libraries with controlled composition and microstructure gradients are suggested. Much of this evaluation can be done now, but key components (materials libraries with microstructure gradients and high-throughput tensile testing are currently missing. Suggestions for future HEA efforts are given.

  18. Structure and growth of oxide on iron-chromium alloys

    International Nuclear Information System (INIS)

    Cox, M.G.C.; McEnaney, B.; Scott, V.D.

    1974-01-01

    Several oxides form during the initial stages of oxidation of iron-chromium alloys at 400 to 600 0 C in CO 2 -1%CO gas. The nature of the oxidation product depends upon crystallographic orientation and composition of the substrate, and can be explained by considering the maximum solubility of chromium in different oxide phases together with interfacial and strain energy factors. Kinetics of oxidation together with micrographic observations indicate that, as oxidation proceeds spinel oxide M 3 O 4 nucleates at sites on the substrate surface associated with asperities. The spinel nuclei grow laterally and vertically until they coalesce and the scale subsequently thickens according to a parabolic rate law. The duplex structure of scales is interpreted in terms of an outward diffusion of cations together with simultaneous growth of an inner layer in the space created by this outward movement. Scale porosity provides a route for gas-phase transport of oxidant to support the growth of the inner layer. Regularly spaced lamellar voids which may form in the inner layer are believed to be associated with a cyclic vacancy condensation process. Enrichment of the inner layer in chromium is explained by analysis of the possible diffusion path networks in close-packed oxides. Some comments are made concerning possible practical applications of these data. (author)

  19. Low activation materials for fusion

    International Nuclear Information System (INIS)

    Rowcliffe, A.F.; Bloom, E.E.; Doran, D.G.; Smith, D.L.; Reuther, T.C.

    1988-01-01

    The viability of fusion as a future energy source may eventually be determined by safety and environmental factors. Control of the induced radioactivity characteristics of the materials used in the first wall and blanket could have a major favorable impact on these issues. In the United States, materials program efforts are focused on developing new structural alloys with radioactive decay characteristics which would greatly simplify long-term waste disposal of reactor components. A range of alloy systems is being explored in order to maintain the maximum number of design options. Significant progress has been made, and it now appears probable that reduced-activation engineering alloys with properties at least equivalent to conventional alloys can be successfully developed and commercialized. 10 refs., 1 fig

  20. Nucleation and growth of fatigue cracks in magnesium alloys of different structure

    International Nuclear Information System (INIS)

    Grinberg, N.M.; Serdyuk, V.A.; Malinkina, T.I.; Kamyshkov, A.S.

    1982-01-01

    Duration of the fatigue crack nucleation and growth rate have been in a wide range of stress intensity factor variations for MA2-1, MA2-1 hp (higher purity), MA12, (T2, T6 and T8), MA15, IMB6, MA21 magnesium alloys of different composition and structural state. The threshold and criti- cal values of stress intensity factors, Ksub(th) and Ksub(fc) are determined for those alloys, and morphology of fracture is studied at different stages of crack growth. Duration of the nucleation stage of a fatigue crack, the rate and micromechanisms of its growth are found to depedend on alloying and structural state of magnesium alloys. The best crack resistance characteristics has the MA2-1 alloy, the poorest - MA12 (T2) alloy. It is stated that thermal treatment by hardening and ageing increases the resistance of the MA12 alloy to fatigue fracture and the MA2-1 alloy of higher purity gives poorer parameters of crack resistance [ru

  1. A two potential embedding approach to the electronic structure of disordered binary alloys

    International Nuclear Information System (INIS)

    Ahmed, M.; Mookerjee, A.

    1988-06-01

    Using an embedding technique introduced in a recent publication by one of us, we study the electronic structure of disordered binary alloys within a pair-cluster coherent potential approximation. (author). 4 refs, 3 figs

  2. Special quasirandom structures for binary/ternary group IV random alloys

    KAUST Repository

    Chroneos, Alexander I.; Jiang, Chao; Grimes, Robin W.; Schwingenschlö gl, Udo

    2010-01-01

    Simulation of defect interactions in binary/ternary group IV semiconductor alloys at the density functional theory level is difficult due to the random distribution of the constituent atoms. The special quasirandom structures approach is a

  3. Structural and magnetic properties of holmium-scandium alloys and superlattices

    DEFF Research Database (Denmark)

    Bryn-Jacobsen, C.; Cowley, R.A.; McMorrow, D.F.

    1997-01-01

    The properties of Ho-Sc alloys and superlattices grown by molecular-beam epitaxy have been investigated using x-ray and neutron-diffraction techniques. Structural studies reveal that the alloy samples have different a lattice parameters for the Sc-seed layer and the Ho:Sc alloy grown on top...... of the seed layer; while the superlattices have different a lattice parameters for the Sc seed, and for both the Ho and Sc in the superlattice layers. The structural characteristics are related to the large lattice mismatches (of the order 7%) between the constituent elements. The magnetic moments...

  4. Pore structure and mechanical properties of directionally solidified porous aluminum alloys

    Directory of Open Access Journals (Sweden)

    Komissarchuk Olga

    2014-01-01

    Full Text Available Porous aluminum alloys produced by the metal-gas eutectic method or GASAR process need to be performed under a certain pressure of hydrogen, and to carry over melt to a tailor-made apparatus that ensures directional solidification. Hydrogen is driven out of the melt, and then the quasi-cylindrical pores normal to the solidification front are usually formed. In the research, the effects of processing parameters (saturation pressure, solidification pressure, temperature, and holding time on the pore structure and porosity of porous aluminum alloys were analyzed. The mechanical properties of Al-Mg alloys were studied by the compressive tests, and the advantages of the porous structure were indicated. By using the GASAR method, pure aluminum, Al-3wt.%Mg, Al-6wt.%Mg and Al-35wt.%Mg alloys with oriented pores have been successfully produced under processing conditions of varying gas pressure, and the relationship between the final pore structure and the solidification pressure, as well as the influences of Mg quantity on the pore size, porosity and mechanical properties of Al-Mg alloy were investigated. The results show that a higher pressure of solidification tends to yield smaller pores in aluminum and its alloys. In the case of Al-Mg alloys, it was proved that with the increasing of Mg amount, the mechanical properties of the alloys sharply deteriorate. However, since Al-3%Mg and Al-6wt.%Mg alloys are ductile metals, their porous samples have greater compressive strength than that of the dense samples due to the existence of pores. It gives the opportunity to use them in industry at the same conditions as dense alloys with savings in weight and material consumption.

  5. Structure and Mechanical Properties of Al-Cu-Fe-X Alloys with Excellent Thermal Stability

    OpenAIRE

    Školáková, Andrea; Novák, Pavel; Mejzlíková, Lucie; Průša, Filip; Salvetr, Pavel; Vojtěch, Dalibor

    2017-01-01

    In this work, the structure and mechanical properties of innovative Al-Cu-Fe based alloys were studied. We focused on preparation and characterization of rapidly solidified and hot extruded Al-Cu-Fe, Al-Cu-Fe-Ni and Al-Cu-Fe-Cr alloys. The content of transition metals affects mechanical properties and structure. For this reason, microstructure, phase composition, hardness and thermal stability have been investigated in this study. The results showed exceptional thermal stability of these allo...

  6. Structural investigations of mechanical properties of Al based rapidly solidified alloys

    International Nuclear Information System (INIS)

    Karakoese, Ercan; Keskin, Mustafa

    2011-01-01

    Highlights: → Rapid solidification processing (RSP) involves exceptionally high cooling rates. → We correlate the microstructure of the intermetallic Al 3 Fe, Al 2 Cu and Al 3 Ni phases with the cooling rate. → The solidification rate is high enough to retain most of alloying elements in the Al matrix. → The rapid solidification has effect on the phase constitution. -- Abstract: In this study, Al based Al-3 wt.%Fe, Al-3 wt.%Cu and Al-3 wt.%Ni alloys were prepared by conventional casting. They were further processed using the melt-spinning technique and characterized by the X-ray diffraction (XRD), scanning electron microscopy (SEM) together with energy dispersive spectroscopy (EDS), transmission electron microscope (TEM), differential scanning calorimetry (DSC) and the Vickers microhardness tester. The rapidly solidified (RS) binary alloys were composed of supersaturated α-Al solid solution and finely dispersed intermetallic phases. Experimental results showed that the mechanical properties of RS alloys were enhanced, which can be attributed to significant changes in the microstructure. RS samples were measured using a microhardness test device. The dependence of microhardness H V on the solidification rate (V) was analysed. These results showed that with the increasing values of V, the values of H V increased. The enthalpies of fusion for the same alloys were determined by DSC.

  7. Photoelectron spectroscopic study on the electronic structures of the dental gold alloys and their interaction with L-cysteine

    International Nuclear Information System (INIS)

    Ogawa, Koji; Takahashi, Kazutoshi; Azuma, Junpei; Kamada, Masao; Tsujibayashi, Toru; Ichimiya, Masayoshi; Fujimoto, Hitoshi; Sumimoto, Michinori

    2011-01-01

    The valence electronic structures of the dental gold alloys, type 1, type 3, and K14, and their interaction with L-cysteine have been studied by ultraviolet photoelectron spectroscopy with synchrotron radiation. It was found that the electronic structures of the type-1 and type-3 dental alloys are similar to that of polycrystalline Au, while that of the K14 dental alloy is much affected by Cu. The peak shift and the change in shape due to alloying are observed in all the dental alloys. It is suggested that the new peak observed around 2 eV for the L-cysteine thin films on all the dental alloys may be due to the bonding of S 3sp orbitals with the dental alloy surfaces, and the Cu-S bond, as well as the Au-S and Au-O bonds, may cause the change in the electronic structure of the L-cysteine on the alloys.

  8. Life cycle assessment of metal alloys for structural applications

    Science.gov (United States)

    Malovrh Rebec, K.; Markoli, B.; Leskovar, B.

    2018-03-01

    The study compared environmental footprints of two types of Al-alloys: well-known 5083 aluminium alloy with magnesium and traces of manganese and chromium in its composition. This material is highly resistant to seawater corrosion and the influence of industrial chemicals. Furthermore, it retains exceptional strength after welding. The comparisons were made to an innovative alloy where the aluminium based matrix is reinforced by metastable quasicrystals (QC), thus avoiding magnesium in its composition. Furthermore, we checked other aluminium ingots’ footprints and compared European average and Germany country specific production data. Environmental footprints were assessed via cradle to gate life cycle assessment. Our findings normalized to 1 m2 plate suggest, that newly proposed alloy could save around 50 % in value of parameters abiotic resources depletion of fossil fuels, acidification, eutrophication, global warming potential and photochemical ozone creation potential if we compare Qc5 to 6 mm 5083 alloy plate. Only abiotic resources depletion of elements and ozone depletion parameters increase for Qc5 compared to 6 mm 5083 alloy plate.

  9. Structure, activity, and stability of platinum alloys as catalysts for the oxygen reduction reaction

    DEFF Research Database (Denmark)

    Vej-Hansen, Ulrik Grønbjerg

    In this thesis I present our work on theoretical modelling of platinum alloys as catalysts for the Oxygen Reduction Reaction (ORR). The losses associated with the kinetics of the ORR is the main bottleneck in low-temperature fuel cells for transport applications, and more active catalysts...... are essential for wide-spread use of this technology. platinum alloys have shown great promise as more active catalysts, which are still stable under reaction conditions. We have investigated these systems on multiple scales, using either Density Functional Theory (DFT) or Effective Medium Theory (EMT......), depending on the length and time scales involved. Using DFT, we show how diffusion barriers in transition metal alloys in the L12 structure depend on the alloying energy, supporting the assumption that an intrinsically more stable alloy is also more stable towards diffusion-related degradation...

  10. Electronic structure and properties of disordered alloys of d-elements

    International Nuclear Information System (INIS)

    Demidenko, V.S.; Kal'yanov, A.P.

    1983-01-01

    On the basis of coherent potential approximation the fundamental characteristics in which transition element alloys differ have been established. Connection of the characteristics with position of the elements alloyed in the Mendeleev table is considered. It is confirmed by calculations that electronic structure and, consequently, physical properties of the alloys of a certain value potential disturbing matrix, change qualitatively. Results of the calculation of electron energy state density, diagrams of partial and average magnetic momenta in binary and ternary alloys of the first transition period, are presented. Besides, calculation results of bond energy in d-metals and energy of segregation formation in their alloys are also given. Comparison with experiment confirms the efficiency of concepts given in the paper

  11. Aluminum Lithium Alloy 2195 Fusion Welding Improvements with New Filler Wire

    Science.gov (United States)

    Russell, C.

    2001-01-01

    The objective of this research was to assess the B218 weld filler wire for Super Lightweight External Tank production, which could improve current production welding and repair productivity. We took the following approaches: (1) Perform a repair weld quick look evaluation between 4043/B218 and B218/B218 weld filler wire combinations and evaluation tensile properties for planished and unplanished conditions; and (2) Perform repair weld evaluation on structural simulation panel using 4043-B218 and B218/B218 weld filler wire combinations and evaluation tensile and simulated service fracture properties for planished and unplanished conditions.

  12. Influence of melting and filtration processes on the structure and mechanical properties of aluminum alloys

    Directory of Open Access Journals (Sweden)

    M. Dudyk

    2008-10-01

    Full Text Available In the article are presented the results of the study on the applied upgrading processes such as refining, modification and filtration of thenear eutectics alloy EN AC- 44000, AlSi11, (AK11, cast into the chill. The upgrading processes applied to the said alloy caused, incomparison to the alloy which was not upgraded, significant differences in the shape of the crystallization curves, obtained in the graphicrecord of the ATD-AED method. It was demonstrated the existence of connections between the thermal and electric phenomena duringsolidification and crystallization of the studied silumin. The obtained results of the metallographic analysis showed the occurrence of theimpurities within the alloy structure in the form of porosity and oxides following the metallurgical processing (in pig sows. The primarystudies on microstructure of the cast ceramic filters have demonstrated the purposefulness of introduction of the filtration process to thetechnology of aluminum alloys manufacturing. The microstructures of the filters cast with the studied alloys illustrate the extent anddeployment of the impurities retained (in the filter during the process of samples casting for measurement of the mechanical strengthproperties. On the example of the near eutectics alloy AK11, it has been demonstrated, that in comparison to the refined alloy there isa possibility to obtain significant improvement of mechanical properties, and especially elongation A5 and impact strength KCV.

  13. Compatibility of 316L stainless steel with tritium breeders for fusion reactors

    International Nuclear Information System (INIS)

    Broc, M.; Fauvet, P.; Flament, T.; Sannier, J.

    1986-06-01

    Compatibility problems with structural materials are a concern for the choice of the tritium breeder for fusion reactors. In the frame of the European Programme on Fusion Technology, two types of blankets are considered: liquid (eutectic lithium-lead alloy at 0.68 wt % Li: 17Li83Pb) and solid (lithium aluminate or silicate) breeders. This paper is devoted to compatibility studies of 316L stainless steel with 17Li83Pb alloy and γ-LiA10 2 ceramic

  14. Structural transformations of heat treated Co-less high entropy alloys

    Science.gov (United States)

    Mitrica, D.; Tudor, A.; Rinaldi, A.; Soare, V.; Predescu, C.; Berbecaru, A.; Stoiciu, F.; Badilita, V.

    2018-03-01

    Co is considered to be one of the main ingredients in superalloys. Co is considered a critical element and its substitution is difficult due to its unique ability to form high temperature stable structures with high mechanical and corrosion/oxidation resistance. High entropy alloys (HEA) represent a relatively new concept in material design. HEA are characterised by a high number of alloying elements, in unusually high proportion. Due to their specific particularities, high entropy alloys tend to form predominant solid solution structures that develop potentially high chemical, physical and mechanical properties. Present paper is studying Co-less high entropy alloys with high potential in severe environment applications. The high entropy alloys based on Al-Cr-Fe-Mn-Ni system were prepared by induction melting and casting under protective atmosphere. The as-cast specimens were heat treated at various temperatures to determine the structure and property behaviour. Samples taken before and after heat treatment were investigated for chemical, physical, structural and mechanical characteristics. Sigma phase composition and heat treatment parameters had major influence over the resulted alloy structure and properties.

  15. Dislocation structure evolution and characterization in the compression deformed Mn-Cu alloy

    International Nuclear Information System (INIS)

    Zhong, Y.; Yin, F.; Sakaguchi, T.; Nagai, K.; Yang, K.

    2007-01-01

    Dislocation densities and dislocation structure arrangements in cold compressed polycrystalline commercial M2052 (Mn-20Cu-5Ni-2Fe) high damping alloy with various strains were determined in scanning mode by X-ray peak profile analysis and electron backscatter diffraction (EBSD). The results indicate that the Mn-Cu-Ni-Fe alloy has an evolution behavior quite similar to the dislocation structure in copper. The dislocation arrangement parameter shows a local minimum in the transition range between stages III and IV that can be related to the transformation of the dislocation arrangement in the cell walls from a polarized dipole wall (PDW) into a polarized tile wall (PTW) structure. This evolution is further confirmed by the results of local misorientation determined by EBSD. In addition, during deformation, the multiplication of dislocation densities in the MnCu alloy is significantly slower than that in copper, and the transition of the dislocation structure is strongly retarded in the MnCu alloy compared with copper. These results can be explained by the mechanism of elastic anisotropy on the dislocation dynamics, as the elastic anisotropy in the MnCu alloy is larger than that in copper, which can strongly retard the multiplication of the dislocation population and the transformation of the dislocation structure. These results are important for research into the plastic working behavior of Mn-Cu-Ni-Fe high damping alloy

  16. Structure of disordered alloys - II: self-consistent CCPA calculations for III-V semiconducting alloys

    International Nuclear Information System (INIS)

    Mookerjee, A.; Chaudhry, V.

    1980-09-01

    Using the chemical pseudopotential approach of Anderson and Bullett we have generated from first principles pseudo-Hamiltonians for heteropolar alloys. The one-electron density of states has been generated for Gasub(x)Insub(1-x)As using a self-consistent cluster CPA introduced earlier by one of us. Off-diagonal disorder has also been incorporated. (author)

  17. The structure and mechanical properties of as-cast Zr-Ti alloys

    International Nuclear Information System (INIS)

    Hsu, H.-C.; Wu, S.-C.; Sung, Y.-C.; Ho, W.-F.

    2009-01-01

    This study has investigated the structure and mechanical properties of pure Zr and a series of binary Zr-Ti alloys in order to determine their potential application as dental implant materials. The titanium contents of these alloys range from 10 to 40 wt.% and were prepared by arc melting in inert gas. This study evaluated the phase and structure of these Zr-Ti alloys using an X-ray diffraction (XRD) for phase analysis, and an optical microscope for microstructure analysis of the etched alloys. Three-point bending tests were performed to evaluate the mechanical properties of all specimens. The experimental results indicated that the pure Zr and Zr-10Ti comprised entirely of an acicular hexagonal structure of α' phase. When the Ti content increased to 20 wt.%, a significant amount of β phase was retained. However, when the Ti content increased to 40 wt.%, only the equi-axed, retained β phase was observed in the cast alloy. Moreover, the hardness values and bending strengths of the Zr-Ti alloys decreased with an increasing Ti content. Among pure Zr and Zr-Ti alloys, the α'-phase Zr-10Ti alloy has the greatest hardness and bending strength. The pure Zr and Zr-Ti alloys exhibit a similar elastic modulus ranging from 68 GPa (Zr-30Ti) to 78 GPa (Zr-40Ti). Based on the results of elastic moduli, pure Zr and Zr-Ti alloys are found to be suitable for implant materials due to lower modulus. Like bending strength, the elastically recoverable angle of Zr-Ti alloys decreased as the concentration of Ti increased. In the current search for a better implant material, the Zr-10Ti alloy exhibited the highest bending strength/modulus ratios as large as 25.3, which are higher than that of pure Zr (14.9) by 70%, and commercially pure Ti (8.7) by 191%. Thus, Zr-Ti alloy's low modulus, ductile property, excellent elastic recovery capability and impressive strength confirm that it is a promising candidate for dental implant materials.

  18. Structure and grindability of cast Ti-5Cr-xFe alloys

    International Nuclear Information System (INIS)

    Hsu, H.-C.; Pan, C.-H.; Wu, S.-C.; Ho, W.-F.

    2009-01-01

    The purpose of this study was to investigate the structure, microhardness and grindability of Ti-5Cr and a series of ternary Ti-5Cr-xFe alloys with 0.1, 0.5, 1, 3 and 5 wt.% Fe, respectively. This study evaluated the phase and structure of Ti-5Cr and Ti-5Cr-xFe alloys, using an X-ray diffraction (XRD) for phase analysis and optical microscope for microstructure of the etched alloys. In addition, grindability was evaluated by measuring the amount of metal volume removed after grinding for 1 min at each of the four rotational speeds of the wheel (500, 750, 1000 or 1200 m/min), with the goal of developing a titanium alloy with better machinability than commercially pure titanium (c.p. Ti). The results showed that the structure of Ti-5Cr-xFe alloys is sensitive to the Fe content. With Fe contents higher than 0.5 wt.%, the equi-axed β phase is entirely retained, while ω phase was found in the Ti-5Cr, Ti-5Cr-0.1Fe, Ti-5Cr-0.5Fe and Ti-5Cr-1Fe alloys. The largest quantity of ω phase and highest microhardness were found in Ti-5Cr-0.5Fe and Ti-5Cr-1Fe alloys. The grinding rates of the Ti-5Cr and Ti-5Cr-xFe alloys showed a similar tendency to the microhardness. The Ti-5Cr, Ti-5Cr-0.1Fe, Ti-5Cr-0.5Fe and Ti-5Cr-1Fe alloys exhibited the best grindability, especially at 500, 750 and 1000 m/min. Furthermore, the grindability of the tested metals increased in proportion to grinding speed up to 1000 m/min, with a decrease after 1200 m/min. This study concluded that Fe may be used to harden titanium and improve the grindability

  19. The corrosion behaviour and structure of amorphous and thermally treated Fe-B-Si alloys

    International Nuclear Information System (INIS)

    Raicheff, R.; Zaprianova, V.; Petrova, E.

    2003-01-01

    The corrosion behaviour of magnetic amorphous alloys Fe 78 B 13 Si 9 , Fe 81 B 13 Si 4 C 2 and Fe 67 Co 18 Bi 4 S 1 obtained by rapid quenching from the melts are investigated in a model corrosive environment of 1N H 2 SO 4 . The structure of the alloys, is, characterized by DTA, SEM, TEM, X-ray and electron diffraction techniques. The dissolution kinetics of the,alloys is studied using gravimetric and electrochemical polarization measurements. It is established that the corrosion rate of the amorphous Fe 67 Co 18 Bt 4 S 1 alloy is up to 50 times lower than that of Fe 78 Bi 3 Si 9 alloy and the addition of cobalt leads to a considerable reduction of the rates of both partial corrosion reactions, while the addition of carbon results only in a moderate decrease (2-3 times) of the corrosion rate. It is also shown that the crystallization of the amorphous Fe 78 B 13 Si 9 alloy (at 700 o C for 3 h) leads to formation of multiphase structure consisting of crystalline phases α-Fe and Fe 3 (B,Si). After crystallization an increase of the rate of both hydrogen evolution and anodic dissolution reactions is observed which results in a considerable (an order of magnitude) increase of the corrosion rate of the alloy. (Original)

  20. Structure of the cleavage-activated prefusion form of the parainfluenza virus 5 fusion protein.

    Science.gov (United States)

    Welch, Brett D; Liu, Yuanyuan; Kors, Christopher A; Leser, George P; Jardetzky, Theodore S; Lamb, Robert A

    2012-10-09

    The paramyxovirus parainfluenza virus 5 (PIV5) enters cells by fusion of the viral envelope with the plasma membrane through the concerted action of the fusion (F) protein and the receptor binding protein hemagglutinin-neuraminidase. The F protein folds initially to form a trimeric metastable prefusion form that is triggered to undergo large-scale irreversible conformational changes to form the trimeric postfusion conformation. It is thought that F refolding couples the energy released with membrane fusion. The F protein is synthesized as a precursor (F0) that must be cleaved by a host protease to form a biologically active molecule, F1,F2. Cleavage of F protein is a prerequisite for fusion and virus infectivity. Cleavage creates a new N terminus on F1 that contains a hydrophobic region, known as the FP, which intercalates target membranes during F protein refolding. The crystal structure of the soluble ectodomain of the uncleaved form of PIV5 F is known; here we report the crystal structure of the cleavage-activated prefusion form of PIV5 F. The structure shows minimal movement of the residues adjacent to the protease cleavage site. Most of the hydrophobic FP residues are buried in the uncleaved F protein, and only F103 at the newly created N terminus becomes more solvent-accessible after cleavage. The conformational freedom of the charged arginine residues that compose the protease recognition site increases on cleavage of F protein.

  1. The effect of thermohydrogen treatment on the structure and properties of casts obtained from titanium alloys

    International Nuclear Information System (INIS)

    Il'in, A.A.; Skvortsova, S.V.; Mamonov, A.M.; Permyakova, G.V.; Kurnikov, D.A.

    2002-01-01

    The method based on the combination of high temperature gas-static and thermal hydrogen treatments is suggested to increase mechanical properties of cast pseudo-α and (α+β)-titanium alloys. The study is carried out using alloys VT20L, VT23L and alloy Ti-6%Al-2%Mo-4%Zr-2%Sn. It is shown that the method proposed provides the change in a cast structure, an increase in density of castings, an increase of strength properties by 10-20% and fatigue by a factor of 1.5-2 at satisfactory ductility and impact strength [ru

  2. Structural transformations and temperature state of rotating blades of E1893 alloy under operation

    Energy Technology Data Exchange (ETDEWEB)

    Pigrova, G.D.; Rybnikov, A.I.; Kryukov, I.I. [Polzunov Central Boiler and Turbine Institute, St. Petersburg (Russian Federation)

    1998-12-31

    The composition and quantity of different phase component of EI893 alloy after long term operation as base metal for rotating blades of gas turbines GT-6, GTN-9, GTK-10 and GT-100 types were studied. The obtained date were analysed with regard to the chemical composition of alloys and of initial condition of heat treatment. Data of metal phase analysis owned alter operation can provide the basis for evaluation of tempera field of rotating blades in the course of operation since structural condition of phase components and redistribution of alloying elements are being specified by temperature and in-service time. (orig.)

  3. The influence of interfacial energies and gravitational levels on the directionally solidified structures in hypermonotectic alloys

    Science.gov (United States)

    Andrews, J. B.; Curreri, P. A.; Sandlin, A. C.

    1988-01-01

    Various Cu-Pb-Al alloys were directionally solidified under 1-g conditions and alternating high-g/low-g conditions (achieved using NSAS's KC-135 aircraft) as a means of studying the influence of interfacial energies and gravitational levels on the resulting microstructures. Directional solidification of low Al content alloys was found to result in samples with coarser more irregular microstructures than in alloys with high Al contents under all the gravity conditions considered. Structures are correlated with interfacial energies, growth rates, and gravitational levels.

  4. Investigation of structural transformations in the Nb-Ti-Al alloy system

    International Nuclear Information System (INIS)

    Vergasova, L.L.; Volin, Eh.M.; Chizhov, I.N.; Lokshina, A.E.

    1975-01-01

    There are given the results of investigating the effect of thermal treatment conditions upon the structure, the phase composition and the mechanical characteristic of VN7 alloy from Nb-Ti-Al system. VN7 alloy was investigated in cast, forged, pressed and rolled state to study the β-α-conversion processes at slow cooling from high temperature. It was found out that slow cooling lowers considerably the plastic characteristic and the impact ductility without changing practically the tensile strength values. Higher plastic characteristic of VN7 alloy can be obtained through hastening the cooling process of the intermediate products after annealing at 950-1050 0 C

  5. Structural transformations and temperature state of rotating blades of E1893 alloy under operation

    Energy Technology Data Exchange (ETDEWEB)

    Pigrova, G D; Rybnikov, A I; Kryukov, I I [Polzunov Central Boiler and Turbine Institute, St. Petersburg (Russian Federation)

    1999-12-31

    The composition and quantity of different phase component of EI893 alloy after long term operation as base metal for rotating blades of gas turbines GT-6, GTN-9, GTK-10 and GT-100 types were studied. The obtained date were analysed with regard to the chemical composition of alloys and of initial condition of heat treatment. Data of metal phase analysis owned alter operation can provide the basis for evaluation of tempera field of rotating blades in the course of operation since structural condition of phase components and redistribution of alloying elements are being specified by temperature and in-service time. (orig.)

  6. Recent progress on gas tungsten arc welding of vanadium alloys

    Energy Technology Data Exchange (ETDEWEB)

    King, J.F.; Grossbeck, M.L.; Goodwin, G.M.; Alexander, D.J. [Oak Ridge National Lab., TN (United States)

    1997-04-01

    This is a progress report on a continuing research project to acquire a fundamental understanding of the metallurgical processes in the welding of vanadium alloys. It also has the goal of developing techniques for welding structural vanadium alloys. The alloy V-4Cr-4Ti is used as a representative alloy of the group; it is also the prime candidate vanadium alloy for the U.S. Fusion Program at the present time. However, other alloys of this class were used in the research as necessary. The present work focuses on recent findings of hydrogen embrittlement found in vanadium alloy welds. It was concluded that the atmosphere in the inert gas glove box was insufficient for welding 6mm thick vanadium alloy plates.

  7. Structural Investigation of Rapidly Quenched FeCoPtB Alloys

    International Nuclear Information System (INIS)

    Grabias, A.; Kopcewicz, M.; Latuch, J.; Oleszak, D.

    2011-01-01

    Two sets of Fe 52-x Co x Pt 28 B 20 (x = 0-26 at.%) and Fe 60-x Co x Pt 25 B 15 (x = 0-40 at.%) alloys were prepared in the form of ribbons by the rapid quenching technique. Structure of the samples was characterized by Moessbauer spectroscopy and X-ray diffraction. In the as-quenched alloys the amorphous phase coexisted with the fcc-(Fe,Co)Pt disordered solid solution. Differential scanning calorimetry measurements performed in the range 50-720 ± C revealed one or two exothermal peaks. The magnetically hard ordered L1 0 (Fe,Co)Pt and magnetically soft (Fe,Co) 2 B nanocrystalline phases were formed due to thermal treatment of the alloys. The influence of Co content on the structure of the as-quenched and heated alloys was studied. (authors)

  8. Effect of the structure on the low-cycle fatigue behaviour of alloy 800

    International Nuclear Information System (INIS)

    Robert, G.; Mathiot, A.; Regnard, C.; Dessus, J.; Claret, J.

    1982-04-01

    Alloy 800 (grade I) is used for making the steam generators of liquid metal fast breeder reactors. At working temperature (525 0 C) alloy 800 is strengthned by γ' (Ni 3 (Ti,Al)) precipitation which occurs during thermal aging. The mechanical properties of this alloy depend on the parameters which define the γ' precipitation and obviously on the structural characteristics due to the thermomechanical treatments which govern the manufacture of the product. For one cast of alloy 800 this work aims to analyse the influence, on low cycle fatigue behaviour at 550 0 C, of structural and microstructural variations originating either in different elaboration procedures or in γ' precipitation obtained by a thermal aging of 3000h at 550 0 C with or without a preceeding cold working of 10% [fr

  9. Solid-State Nuclear Magnetic Resonance Investigation of the Structural Topology and Lipid Interactions of a Viral Fusion Protein Chimera Containing the Fusion Peptide and Transmembrane Domain.

    Science.gov (United States)

    Yao, Hongwei; Lee, Myungwoon; Liao, Shu-Yu; Hong, Mei

    2016-12-13

    The fusion peptide (FP) and transmembrane domain (TMD) of viral fusion proteins play important roles during virus-cell membrane fusion, by inducing membrane curvature and transient dehydration. The structure of the water-soluble ectodomain of viral fusion proteins has been extensively studied crystallographically, but the structures of the FP and TMD bound to phospholipid membranes are not well understood. We recently investigated the conformations and lipid interactions of the separate FP and TMD peptides of parainfluenza virus 5 (PIV5) fusion protein F using solid-state nuclear magnetic resonance. These studies provide structural information about the two domains when they are spatially well separated in the fusion process. To investigate how these two domains are structured relative to each other in the postfusion state, when the ectodomain forms a six-helix bundle that is thought to force the FP and TMD together in the membrane, we have now expressed and purified a chimera of the FP and TMD, connected by a Gly-Lys linker, and measured the chemical shifts and interdomain contacts of the protein in several lipid membranes. The FP-TMD chimera exhibits α-helical chemical shifts in all the membranes examined and does not cause strong curvature of lamellar membranes or membranes with negative spontaneous curvature. These properties differ qualitatively from those of the separate peptides, indicating that the FP and TMD interact with each other in the lipid membrane. However, no 13 C- 13 C cross peaks are observed in two-dimensional correlation spectra, suggesting that the two helices are not tightly associated. These results suggest that the ectodomain six-helix bundle does not propagate into the membrane to the two hydrophobic termini. However, the loosely associated FP and TMD helices are found to generate significant negative Gaussian curvature to membranes that possess spontaneous positive curvature, consistent with the notion that the FP-TMD assembly may

  10. Chromium surface alloying of structural steels during laser treatment

    International Nuclear Information System (INIS)

    Kurov, I.E.; Nagornykh, S.N.; Sivukhin, G.A.; Solenov, S.V.

    1987-01-01

    Results of matrix alloying from the surface layer and creation of considerably increased chromium concentration in the depth which permits to increase the efficiency of laser treatment of steels (12Kh18N10T and 38KhN3M) in the process of their further mechanical polishing, are presented. The treatment was realized by continuous CO 2 -laser at different power densities and scanning rates are presented. A model describing the creation of anomalous distributions of the alloying element in steels is plotted

  11. Structural and magnetic study of mechanically deformed Fe rich FeAlSi ternary alloys

    International Nuclear Information System (INIS)

    Legarra, E.; Apiñaniz, E.; Plazaola, F.

    2012-01-01

    Highlights: ► Addition of Si to binary Fe–Al alloys makes the disordering more difficult. ► Si addition opposes the large volume increase found in FeAl alloys with deformation. ► Disordering induces a redistribution of non-ferrous atoms around Fe atoms in Fe 75 Al 25−x Si x and Fe 70 Al 30−x Si x . ► Addition of Si to binary Fe 75 Al 25 and Fe 70 Al 30 alloys opposes the magnetic behavior induced by Al in the magnetism of Fe. ► Si inhibits the para-ferro transition found in Fe 60 Al 40 alloy with disordering. - Abstract: In this work we study systematically the influence of different Al/Si ratios on the magnetic and structural properties of mechanically disordered powder Fe 75 Al 25−x Si x , Fe 70 Al 30−x Si x and Fe 60 Al 40−x Si x alloys by means of Mössbauer spectroscopy, X-ray diffraction and magnetic measurements. In order to obtain different stages of disorder the alloys were deformed by different methods: crushing induction melted alloys and ball milling annealed (ordered) alloys using different number of balls and speed. X-ray and Mössbauer data show that mechanical deformation induces the disordered A2 structure in these alloys. The results indicate that addition of Si to binary Fe–Al alloys makes the disordering more difficult. In addition, X-ray diffraction patterns show that the normalized lattice parameter variation of the disordered alloys of each composition decreases monotonically with Si content, indicating clearly that Si addition opposes the large volume increase found in FeAl alloys with deformation. The study of the hyperfine fields indicates that there is a redistribution of non-ferrous atoms around Fe atoms with the disordering; indeed, there is an inversion of the behavior of the hyperfine field of the Fe atoms. On the other hand, the magnetic measurements indicate that addition of Si to binary Fe 75 Al 25 and Fe 70 Al 30 alloys opposes the magnetic behavior induced by Al in the magnetism of Fe.

  12. Structural evolution in films of alloy Zn70Al27Cu3 (ZA27)

    International Nuclear Information System (INIS)

    Zhu, Y.H.; Lee, W.B.; Mei, Z.; To, S.; Sze, Y.K.

    2005-01-01

    Films of alloy ZA27 were produced using electron deposition technique. Structural evolution and phase decomposition of the films were studied. It was found that the alloy films were relatively stable because of a strong preferred crystal orientation of the nano-phases. The dependence of nano-phase stability on the Zn content and the preferred crystal orientation is discussed from point of view of Gibbs free energy

  13. Determination of localized magnetic moments in Fe-Cr-Al alloys and the electron structure

    International Nuclear Information System (INIS)

    Blau, W.

    1977-01-01

    The localized magnetic moments of Fe and Cr are determined by combination of saturation magnetization measurements and magnetic diffuse scattering. Power series characterizing the interactions between the different kinds of atoms in the alloys are chosen to describe the concentration dependence of the magnetic moments. The different terms are discussed on the basis of band structure models valid for dilute alloys taking into account their modification by impurity interactions. (author)

  14. Development of low activation aluminum alloys for reacting plasma experiment

    International Nuclear Information System (INIS)

    Matsumoto, K.; Kawai, H.; Saida, T.; Onozuka, M.

    1986-01-01

    In the advanced fusion devices aiming at D-T burning, structural components such as vacuum vessels, coil casings are exposed to high energy neutrons produced by D-T reaction. From a view point of maintenability of accessibility, low radioactive structural materials are strongly preferred. The authors have developed two types of improved alloys of reduced radioactivity based on 5083 aluminum alloy: Al-Mg-Bi . Cr and Al-Mg-Cu . Zr. Both of the alloys of 50mm thickness have been proved to have excellent material properties virtually equivalent to those of 5083 alloy

  15. Fusion and characterization of a Cu-Zn-Al-Ni alloy of nuclear interest; Fusion y caracterizacion de una aleacion Cu-Zn-Al-Ni de interes nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Zamora R, L.; Arenas A, J.A.; Santana M, J.S. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2003-07-01

    The first part of the work was made in the Melting Laboratory where an ingot of each alloy was obtained under the same conditions. When having the ingots physically, the following thing consisted, in using different techniques for their characterization in the laboratories of Metallography, Scanning Electron Microscopy, (Sem), X-ray diffraction (XRD) and that of mechanical assays. (Author)

  16. Investigation of wetting property between liquid lead lithium alloy and several structural materials for Chinese DEMO reactor

    Science.gov (United States)

    Lu, Wei; Wang, Weihua; Jiang, Haiyan; Zuo, Guizhong; Pan, Baoguo; Xu, Wei; Chu, Delin; Hu, Jiansheng; Qi, Junli

    2017-10-01

    The dual-cooled lead lithium (PbLi) blanket is considered as one of the main options for the Chinese demonstration reactor (DEMO). Liquid PbLi alloy is used as the breeder material and coolant. Reduced activation ferritic/martensitic (RAFM) steel, stainless steel and the silicon carbide ceramic matrix composite (SiCf) are selected as the substrate materials for different use. To investigate the wetting property and inter-facial interactions of PbLi/RAFM steel, PbLi/SS316L, PbLi/SiC and PbLi/SiCf couples, in this paper, the special vacuum experimental device is built, and the 'dispensed droplet' modification for the classic sessile droplet technique is made. Contact angles are measured between the liquid PbLi and the various candidate materials at blanket working temperature from 260 to 480 °C. X-ray photoelectron spectroscopy (XPS) is used to characterize the surface components of PbLi droplets and substrate materials, in order to study the element trans-port and corrosion mechanism. Results show that SiC composite (SiCf) and SiC ceramic show poor wetting properties with the liquid PbLi alloy. Surface roughness and testing temperature only provide tiny improvements on the wetting property below 480 °C. RAFM steel performs better wetting properties and corrosion residence when contacted with molten PbLi, while SS316L shows low corrosion residence above 420 °C for the decomposition of protective surface film mainly consisted of chromic sesquioxide. The results could provide meaningful compatibility database of liquid PbLi alloy and valuable reference in engineering design of candidate structural and functional materials for future fusion blanket.

  17. Structural characteristics and corrosion behavior of biodegradable Mg-Zn, Mg-Zn-Gd alloys.

    Science.gov (United States)

    Kubásek, J; Vojtěch, D

    2013-07-01

    In this research, binary Mg-Zn (up to 3 wt% Zn) and ternary Mg-Zn-Gd (up to 3 wt% Gd, 3 wt% Zn) alloys were prepared by induction melting in an argon atmosphere. The structures of these alloys were characterized using light and scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction and X-ray fluorescence. In addition, Brinell hardness measurements were taken to supplement these studies. Corrosion behavior was evaluated by immersion tests and potentiodynamic measurements in a physiological solution (9 g/l NaCl). Depending on the composition, structures of the as-cast alloys contained α-Mg dendrites, MgZn, Mg5Gd and Mg3Gd2Zn3 phases. Compared to pure Mg, zinc improved the corrosion resistance of binary Mg-Zn. Gadolinium also improved the corrosion resistance in the case of Mg-1Zn-3Gd alloy. The highest corrosion rate was observed for Mg-3Zn-3Gd alloy. Our results improve the understanding of the relationships between the structure and corrosion behavior of our studied alloy systems.

  18. The effect warming time of mechanical properties and structural phase aluminum alloy nickel

    International Nuclear Information System (INIS)

    Husna Al Hasa, M.; Anwar Muchsin

    2011-01-01

    Ferrous aluminum alloys as fuel cladding will experience the process of heat treatment above the recrystallization temperature. Temperature and time of heat treatment will affect the nature of the metal. Heating time allows will affect change in mechanical properties, thermal and structure of the metal phase. This study aims to determine the effect of time of heat treatment on mechanical properties and phase metal alloys. Testing the mechanical properties of materials, especially violence done by the method of Vickers. Observation of microstructural changes made by metallographic-optical and phase structure were analyzed Based on the x-ray diffraction patterns Elemental analysis phase alloy compounds made by EDS-SEM. Test results show the nature of violence AlFeNiMg alloy by heating at 500°C with a warm-up time 1 hour, 2 hours and 3 hours respectively decreased range 94.4 HV, 87.6 HV and 85.1 HV. The nature of violence AlFeNi alloy showed a decrease in line with the longer heating time. Metallographic-optical observations show the microstructural changes with increasing heating time. Microstructure shows the longer the heating time trend equi axial shaped grain structure of growing and the results showed a trend analyst diffraction pattern formation and phase θ α phase (FeAl3) in the alloy. (author)

  19. Structural stability of high entropy alloys under pressure and temperature

    DEFF Research Database (Denmark)

    Ahmad, Azkar S.; Su, Y.; Liu, S. Y.

    2017-01-01

    The stability of high-entropy alloys (HEAs) is a key issue before their selection for industrial applications. In this study, in-situ high-pressure and high-temperature synchrotron radiation X-ray diffraction experiments have been performed on three typical HEAs Ni20Co20Fe20Mn20Cr20, Hf25Nb25Zr25Ti...

  20. Electronic structure of metallic alloys through Auger and photoemission spectroscopy

    International Nuclear Information System (INIS)

    Kleiman, G.G.; Rogers, J.D.; Sundaram, V.S.

    1981-01-01

    A review is presented of experimental results of electron spectroscopy studies for various series of transition metal alloys as well as a model for their interpretation which leads to the possibility for the first time to determine independently relative variations in the dipole barrier and Fermi energy contributions to the work function. (L.C.) [pt

  1. Highly corrosion resistant zirconium based alloy for reactor structural material

    International Nuclear Information System (INIS)

    Ito, Yoichi.

    1996-01-01

    The alloy of the present invention is a zirconium based alloy comprising tin (Sn), chromium (Cr), nickel (Ni) and iron (Fe) in zirconium (Zr). The amount of silicon (Si) as an impurity is not more than 60ppm. It is preferred that Sn is from 0.9 to 1.5wt%, that of Cr is from 0.05 to 0.15wt%, and (Fe + Ni) is from 0.17 to 0.5wt%. If not less than 0.12wt% of Fe is added, resistance against nodular corrosion is improved. The upper limit of Fe is preferably 0.40wt% from a view point of uniform suppression for the corrosion. The nodular corrosion can be suppressed by reducing the amount of Si-rich deposition product in the zirconium based alloy. Accordingly, a highly corrosion resistant zirconium based alloy improved for the corrosion resistance of zircaloy-2 and usable for a fuel cladding tube of a BWR type reactor can be obtained. (I.N.)

  2. Structure and energetics of bimetallic surface confined alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bergbreiter, Andreas; Roetter, Ralf T.; Engstfeld, Albert K.; Hoster, Harry E.; Behm, R. Juergen [Institute of Surface Chemistry and Catalysis, Ulm University (Germany); Gross, Axel [Institute for Theoretical Chemistry, Ulm University (Germany)

    2009-07-01

    The atomic distribution in a number of A{sub x}B{sub 1-x}/B type surface alloys was determined by STM imaging with chemical contrast and statistically evaluated. Whereas in the systems Au{sub x}Pt{sub 1-x}/Pt(111), Ag{sub x}Pt{sub 1-x}/Pt(111), and Pd{sub x}Ru{sub 1-x}/Ru(0001) we find preferences for larger homoatomic aggregates, the atom distribution in Pt{sub x}Ru{sub 1-x}/Ru(0001) and Ag{sub x}Pd{sub 1-x}/Pd(111) is very close to a random one[1]. In Ag{sub x}Pd{sub 1-x}/Pd(111), our data show a small tendency towards clustering for x{sub Ag}<0.5, whereas at x{sub Ag}>0.5 this is reversed to a slight preference for heteroatomic neighborhoods. Based on these experimental results, we have derived effective cluster interaction energies for all surface alloys. These allow us to calculate phase diagrams for the surface alloys that we compare to predictions from theoretical work and to the behaviour of the corresponding bulk systems. We also discuss in how far the different atom distributions affect chemical and catalytic properties of the surface alloys.

  3. Structural stability analysis considerations in fusion reactor plasma chamber design

    International Nuclear Information System (INIS)

    Delaney, M.J.; Cramer, B.A.

    1978-01-01

    This paper presents an approach to analyzing a toroidal plasma chamber for the prevention of both static and dynamic buckling. Results of stability analyses performed for the doublet shaped plasma chamber of the General Atomic 3.8 meter radius TNS ignition test reactor are presented. Load conditions are the static external atmospheric pressure load and the dynamic plasma disruption pulse load. Methods for analysis of plasma chamber structures are presented for both types of load. Analysis for static buckling is based on idealizing the plasma chamber into standard structural shapes and applying classical cylinder and circular torus buckling equations. Results are verified using the Buckling of Shells of Revolution (BOSOR4) finite difference computer code. Analysis for the dynamic loading is based on a pulse buckling analysis method for circular cylinders

  4. Effects of alloying elements on defect structures in the incubation period for void swelling in austenitic stainless steels

    International Nuclear Information System (INIS)

    Horiki, M.; Yoshiie, T.; Huang, S.S.; Sato, K.; Cao, X.Z.; Xu, Q.; Troev, T.D.

    2013-01-01

    Positron lifetime measurements were used to study the effects of alloying elements on the defect structure during the incubation period for void swelling in several fcc model alloys. Pure Ni, four model alloys (Fe–Cr–Ni, Fe–Cr–Ni–Mo–Mn, Fe–Cr–Ni–Mo–Mn–Si and Fe–Cr–Ni–Mo–Mn–Si–Ti), and four commercial alloys (SUS316LSS, SUS316SS, SUS304SS and Ti added modified SUS316SS) were irradiated with electrons and neutrons. Even at 363 and 573 K to a dose of 0.2 dpa, an effect of alloying elements was observed. At 363 K irradiation, voids were formed only in Ni and Fe–Cr–Ni. At 573 K irradiation, voids were formed in Ni and all model alloys, though the concentration depended on the alloying elements. In commercial alloys, precipitates were formed instead of vacancy clusters, which prevented void growth

  5. NASA-UVA light aerospace alloy and structures technology program (LA(sup 2)ST)

    Science.gov (United States)

    Gangloff, Richard P.; Haviland, John K.; Herakovich, Carl T.; Pilkey, Walter D.; Pindera, Marek-Jerzy; Scully, John R.; Starke, Edgar A., Jr.; Stoner, Glenn E.; Thornton, Earl A.; Wawner, Franklin E., Jr.

    1992-01-01

    The general objective of the Light Aerospace Alloy and Structures Technology (LA(sup 2)ST) Program is to conduct interdisciplinary graduate student research on the performance of next generation, light weight aerospace alloys, composites, and thermal gradient structures in collaboration with Langley researchers. Specific technical objectives are established for each research project. We aim to produce relevant data and basic understanding of material behavior and microstructure, new monolithic and composite alloys, advanced processing methods, new solid and fluid mechanics analyses, measurement advances, and critically, a pool of educated graduate students for aerospace technologies. Four research areas are being actively investigated, including: (1) Mechanical and Environmental Degradation Mechanisms in Advanced Light Metals and Composites; (2) Aerospace Materials Science; (3) Mechanics of Materials and Composites for Aerospace Structures; and (4) Thermal Gradient Structures.

  6. Solidification structure and dispersoids in rapidly solidified Ti-Al-Sn-Zr-Er-B alloys

    International Nuclear Information System (INIS)

    Rowe, R.G.; Broderick, T.F.; Koch, E.F.; Froes, F.H.

    1986-01-01

    The microstructure of melt extracted and melt spun titanium alloys containing erbium and boron revealed a duplex solidification structure of columnar grains leading to equiaxed and dendritic structures near the free surface of melt extracted and melt spun alloys. The solidification structure was revealed by apparent boride segregation to cellular, interdendritic and grain boundaries. Precipitation of needle or lath-like TiB particles occurred adjacent to Er/sub 2/O/sub 3/ dispesoid particles in as-rapidly solidified ribbon

  7. Adhesive wear of iron chromium nickel silicon manganese molybdenum niobium alloys with duplex structure

    International Nuclear Information System (INIS)

    Lugscheider, E.; Deppe, E.; Ambroziak, A.; Melzer, A.

    1991-01-01

    Iron nickel chromium manganese silicon and iron chromium nickel manganese silicon molybdenum niobium alloys have a so-called duplex structure in a wide concentration range. This causes an excellent resistance to wear superior in the case of adhesive stress with optimized concentrations of manganese, silicon, molybdenum and niobium. The materials can be used for welded armouring structures wherever cobalt and boron-containing alloy systems are not permissible, e.g. in nuclear science. Within the framework of pre-investigations for manufacturing of filling wire electrodes, cast test pieces were set up with duplex structure, and their wear behavior was examined. (orig.) [de

  8. Regularities of structure formation on different stages of WC-Co hard alloys fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Chernyavskij, K S

    1987-03-01

    Some regularities of structural transformations in powder products of the hard alloys fabrication have been formulated on the basis of results of the author works and other native and foreign reseachers. New data confirming the influene of technological prehistory of carbide powder on the mechanism of its particle grinding as well as the influence of the structural-energy state of WC powder on the course of the WC-Co alloy structure formation processes are given. Some possibilities for the application in practice of the regularities studied are considered.

  9. Quantitative assessment of Aluminium cast Alloys` structural parameters to optimize ITS properties

    Directory of Open Access Journals (Sweden)

    L. Kuchariková

    2017-01-01

    Full Text Available The present work deals with evaluation of eutectic Si (its shape, size, and distribution, dendrite cell size and dendrite arm spacing in aluminium cast alloys which were cast into different moulds (sand and metallic. Structural parameters were evaluated using NIS-Elements image analyser software. This software is imaging analysis software for the evaluation, capture, archiving and automated measurement of structural parameters. The control of structural parameters by NIS Elements shows that optimum mechanical properties of aluminium cast alloys strongly depend on the distribution, morphology, size of eute ctic Si and matrix parameters.

  10. Fusion welding process

    Science.gov (United States)

    Thomas, Kenneth C.; Jones, Eric D.; McBride, Marvin A.

    1983-01-01

    A process for the fusion welding of nickel alloy steel members wherein a ferrite containing pellet is inserted into a cavity in one member and melted by a welding torch. The resulting weld nugget, a fusion of the nickel containing alloy from the members to be welded and the pellet, has a composition which is sufficiently low in nickel content such that ferrite phases occur within the weld nugget, resulting in improved weld properties. The steel alloys encompassed also include alloys containing carbon and manganese, considered nickel equivalents.

  11. Design issues and implications for the structural integrity and lifetime of fusion power plant components

    International Nuclear Information System (INIS)

    Karditas, P.J.

    1996-05-01

    This review discusses, with example calculations, the criteria, and imposed constraints and limitations, for the design of fusion components and assesses the implications for successful design and power plant operation. The various loading conditions encountered during the operation of a tokamak lead to structural damage and possible failure by such mechanisms as yielding, thermal creep rupture and fatigue due to thermal cycling, plastic strain cycling (ratcheting), crack growth-propagation and radiation induced swelling and creep. Of all the possible damage mechanisms, fatigue, creep and their combination are the most important in the structural design and lifetime of fusion power plant components operating under steady or load varying conditions. Also, the effect of neutron damage inflicted onto the structural materials and the degradation of key properties is of major concern in the design and lifetime prediction of components. Structures are classified by, and will be restricted by existing or future design codes relevant to medium and high temperature power plant environments. The ways in which existing design codes might be used in present and near future design activities, and the implications, are discussed; the desirability of an early start towards the development of fusion-specific design codes is emphasised. (UK)

  12. Spatiotemporal Fusion of Remote Sensing Images with Structural Sparsity and Semi-Coupled Dictionary Learning

    Directory of Open Access Journals (Sweden)

    Jingbo Wei

    2016-12-01

    Full Text Available Fusion of remote sensing images with different spatial and temporal resolutions is highly needed by diverse earth observation applications. A small number of spatiotemporal fusion methods using sparse representation appear to be more promising than traditional linear mixture methods in reflecting abruptly changing terrestrial content. However, one of the main difficulties is that the results of sparse representation have reduced expressional accuracy; this is due in part to insufficient prior knowledge. For remote sensing images, the cluster and joint structural sparsity of the sparse coefficients could be employed as a priori knowledge. In this paper, a new optimization model is constructed with the semi-coupled dictionary learning and structural sparsity to predict the unknown high-resolution image from known images. Specifically, the intra-block correlation and cluster-structured sparsity are considered for single-channel reconstruction, and the inter-band similarity of joint-structured sparsity is considered for multichannel reconstruction, and both are implemented with block sparse Bayesian learning. The detailed optimization steps are given iteratively. In the experimental procedure, the red, green, and near-infrared bands of Landsat-7 and Moderate Resolution Imaging Spectrometer (MODIS satellites are put to fusion with root mean square errors to check the prediction accuracy. It can be concluded from the experiment that the proposed methods can produce higher quality than state-of-the-art methods.

  13. The structure of Cu-Cd alloys obtained by electrolysis on monocrystalline silver substrates

    International Nuclear Information System (INIS)

    Lagiewka, E.

    1981-01-01

    The structure of Cu-Cd alloys obtained by electrolysis on monocrystalline silver cathodes with a surface parallel to the (111), (110) and (100) planes has been investigated. It has been found that depending on the range of the cathode potentials, one-phase (phase α) or two-phase (phase α + cadmium) alloy are obtained. In the alloys the occurrence of twins has been observed, the orientation of which is the result of twinning along the [111] planes of crystallites with epitaxial orientation with respect to the cathode surface and of a random orientation of crystallites. The volume of the layer containing crystallites with a random arrangement increases with the obtaining potential of the alloy and with the decrease in the surface density of the cathode atoms. (author)

  14. Local structure of disordered Au-Cu and Au-Ag alloys

    International Nuclear Information System (INIS)

    Frenkel, A. I.; Machavariani, V. Sh.; Rubshtein, A.; Rosenberg, Yu.; Voronel, A.; Stern, E. A.

    2000-01-01

    X-ray-absorption fine structure (XAFS) and x-ray-diffraction (XRD) measurements of disordered alloys Au x Cu 1-x and Au 0.5 Ag 0.5 prepared by melt spinning were performed. In the Au 0.5 Ag 0.5 alloy, no significant local deviations of the atoms from the average fcc lattice were detected while in Au x Cu 1-x alloys, significant deviations of atoms from the average fcc lattice were found. Mean-square vibrations of the Cu-Cu distances revealed by the XAFS in Au x Cu 1-x alloys indicate the weakening of contact between Cu atoms in the dilute limit. Our computer simulation for Au x Cu 1-x clusters of 10 5 atoms reproduces the main features of both the XAFS and XRD data

  15. Structure and properties of alloys of A15 type compounds with carbon

    International Nuclear Information System (INIS)

    Savitskij, E.M.; Efimov, Yu.V.; Myasnikova, E.A.

    1983-01-01

    Microstructure and some properties of the alloys on the base of the phases of A15 type in the V-Si-C, Nb-Si-C, Nb-Sn-C, Nb-Al-C, Nb-Ga-C, V-Ga-C ternary systems are investigated. It is established that in the niobium-rich corners of the A-B-C ternary systems the new ternary conpounds do not form, as a rule, bUt the wide ranges of threephase equilibrium A-A 3 B-C exist. New ternary phases with A15 type structure stabilized with carbon are established only in the Nb-Si-C and V-Al-C systems. Alloying with carbon results in sharp refining of structural components of stable and metastable alloys, promotes transition of the alloys into amorphous state at super fast cooling of the melts as well as increases stability of metastable state of the alloys against tempering. After super fast quenching and tempering Tsub(c) of the ternary alloys close to the A15 phases exceed Tsub(c) of equilibrium samples

  16. Crystal-Structure Contribution to the Solid Solubility in Transition Metal Alloys

    DEFF Research Database (Denmark)

    Ruban, Andrei; Skriver, Hans Lomholt; Nørskov, Jens Kehlet

    1998-01-01

    The solution energies of 4d metals in other 4d metals as well as the bcc-hcp structural energy differences in random 4d alloys are calculated by density functional theory. It is shown that the crystal structure of the host plays a crucial role in the solid solubility. A local virtual bond...

  17. Structure and phase stability of a Pu-0.32 wt% Ga alloy

    Energy Technology Data Exchange (ETDEWEB)

    Wheeler, D.W., E-mail: David.Wheeler@awe.co.uk; Ennaceur, S.M.; Matthews, M.B.; Roussel, P.; Bayer, P.D.

    2016-08-01

    In plutonium-gallium (Pu-Ga) alloys that have a Ga content of 0.3–0.4 wt%, their readiness to transform to α′ renders them of particular interest in efforts to understand the tenuous nature of δ phase stability. The present study is a comprehensive examination of the structure and phase stability of a cast Pu-0.32 wt% Ga alloy, the Ga content being close to the minimum amount needed to retain the δ phase to ambient temperature. The alloy was characterised in both the as-cast condition as well as following a homogenising heat treatment. The 250-h heat treatment at 450 °C was shown to achieve an apparently stable δ-Pu phase. However, the stability of the δ-Pu phase was shown to be marginal: partial transformation to α′-Pu was observed when the alloy was subjected to hydrostatic compression. Similar transformation was also apparent during metallographic preparation as well as during hardness indentation. The results provide new understanding of the nature of δ phase stability. - Highlights: • New insights into the delta phase stability of a Pu-0.32 wt% Ga alloy. • Density and DSC of as-cast alloy both show α-Pu contents of approximately 30%. • The heat-treated alloy has a largely δ-Pu structure at ambient temperature. • Heat-treated alloy susceptible to δ → α transformation during hardness indentation.

  18. Low-activation structural ceramic composites for fusion power reactors: materials development and main design issues

    International Nuclear Information System (INIS)

    Perez, A.S.; Le Bars, N.; Giancarli, L.; Proust, E.; Salavy, J.F.

    1994-01-01

    Development of advanced Low-Activation Materials (LAMs) with favourable short-term activation characteristics is discussed, for the use as structural materials in a fusion power reactor (in order to reduce the risk associated with a major accident, in particular those related with radio-isotopes release in the environment), and to try to approach the concept of an inherently safe reactor. LA Ceramics Composites (LACCs) are the most promising LAMs because of their relatively good thermo-mechanical properties. At present, SiC/SiC composite is the only LACC considered by the fusion community, and therefore is the one having the most complete data base. The preliminary design of a breeding blanket using SiC/SiC as structural material indicated that significant improvement of its thermal conductivity is required. (author) 11 refs.; 3 figs

  19. Effect of projectile structure on evaporation residue yields in incomplete fusion reactions

    CERN Document Server

    Babu, K S; Sudarshan, K; Shrivastava, B D; Goswami, A; Tomar, B S

    2003-01-01

    The excitation functions of heavy residues, representing complete and incomplete fusion products, produced in the reaction of sup 1 sup 2 C and sup 1 sup 3 C on sup 1 sup 8 sup 1 Ta have been measured over the projectile energy range of 5 to 6.5 MeV/nucleon by the recoil catcher method and off-line gamma-ray spectrometry. Comparison of the measured excitation functions with those calculated using the PACE2 code based on the statistical model revealed the occurrence of incomplete fusion reactions in the formation of alpha emission products. The fraction of incomplete fusion cross sections in the sup 1 sup 2 C + sup 1 sup 8 sup 1 Ta reaction was found to be higher, by a factor of approx 2, than that in the sup 1 sup 3 C + sup 1 sup 8 sup 1 Ta reaction. The results have been discussed in terms of the effect of alpha cluster structure of the projectile on incomplete fusion reactions.

  20. Reducing metal alloy powder costs for use in powder bed fusion additive manufacturing: Improving the economics for production

    Science.gov (United States)

    Medina, Fransisco

    AM. Alternative powders can be made by blending or re-spheroidizing HDH and CPTi powders. Machine modifications were performed to allow the testing and manufacturing with these low cost alternative powders. A comparison was made between alternative powders and gas atomized powders. Powders were compared in terms of morphology and at the microstructural level. Flowability of different powder blends was also measured. Finally, a comparison of parts fabricated from the multiple powder blends and gas atomized powder was made. It has been demonstrated that powder blending can produce fully dense parts in the Arcam system by utilizing the double melt technique or HIPing the built pars. The double melt technique increased the density of the sample part and modified the microstructure into finer martensitic grains. The HIP process can make a part fully dense regardless of what percentage of HDH powder blending is used. The HIP process yielded the same microstructure, regardless of the grain structure it started with. This research allows for the reduction of costs using titanium powders in the EBM system, but can also be implemented with more costly elements and alloys using other metal AM technologies. This includes niobium, tantalum, and nickel-based superalloys for use in various industries.

  1. Peaceful fusion

    Energy Technology Data Exchange (ETDEWEB)

    Englert, Matthias [IANUS, TU Darmstadt (Germany)

    2014-07-01

    Like other intense neutron sources fusion reactors have in principle a potential to be used for military purposes. Although the use of fissile material is usually not considered when thinking of fusion reactors (except in fusion-fission hybrid concepts) quantitative estimates about the possible production potential of future commercial fusion reactor concepts show that significant amounts of weapon grade fissile materials could be produced even with very limited amounts of source materials. In this talk detailed burnup calculations with VESTA and MCMATH using an MCNP model of the PPCS-A will be presented. We compare different irradiation positions and the isotopic vectors of the plutonium bred in different blankets of the reactor wall with the liquid lead-lithium alloy replaced by uranium. The technical, regulatory and policy challenges to manage the proliferation risks of fusion power will be addressed as well. Some of these challenges would benefit if addressed at an early stage of the research and development process. Hence, research on fusion reactor safeguards should start as early as possible and accompany the current research on experimental fusion reactors.

  2. Fusion reaction yield in focused discharges with variable energy and plasma fine structure

    International Nuclear Information System (INIS)

    Bortolotti, A.; Brzosko, J.S.; Chiara, P. De; Kilic, H.; Mezzetti, F.; Nardi, V.; Powell, C.; Wang, J.

    1992-01-01

    The same linear correlation between the distribution parameters (ΔT and Max ΔV) of the radial current density J between electrodes and the fusion reaction yield per pulse, Y, in the plasma focus (PF) pinch was quantitatively determined from different PF machines. Contact prints of current-sheath fragments (CSF) ejected from the pinch are obtained from 2.5-MeV-D + ions. CSF's show the same submillimetric fine structure of the pinch. (author) 3 refs., 2 tabs

  3. Effect of initial structure on strengthening and properties of the 35NKhTYu alloy bands

    International Nuclear Information System (INIS)

    Vorontsov, N.M.; Shugaenko, V.K.; Drapiko, P.E.; Chernyakova, L.E.; Patseka, R.F.

    1978-01-01

    Variation in the structure, mechanical strength, plasticity, and elasticity of thin (about 0.15 mm thick) bands of 36NKhTYu alloy after their cold rolling to the reduction degree up to 70% was examined. The influence of the cold plastic deformation on the dislocation structure of the alloy has been determined. By resorting to the method of transmission electron microscopy, the distribution of dislocations depending on the reduction degree has been shown. The character of the influence of the initial structure of bands after their plastic deformation on the process of decomposition of the solid solution and the formation of γ 1 -phase in tempering and a variation in the mechanical properties of 36NKhTYu alloy have been established

  4. Electronic structure studies of a clock-reconstructed Al/Pd(1 0 0) surface alloy

    Science.gov (United States)

    Kirsch, Janet E.; Tainter, Craig J.

    We have employed solid-state Fenske-Hall band structure calculations to examine the electronic structure of Al/Pd(1 0 0), a surface alloy that undergoes a reconstruction, or rearrangement, of the atoms in the top few surface layers. Surface alloys are materials that consist primarily of a single elemental metal, but which have a bimetallic surface composition that is only a few atomic layers in thickness. The results of this study indicate that reconstruction into a clock configuration simultaneously optimizes the intralayer bonding within the surface plane and the bonding between the first and second atomic layers. These results also allow us to examine the fundamental relationship between the electronic and physical structures of this reconstructed surface alloy.

  5. Evolution of twinning in extruded AZ31 alloy with bimodal grain structure

    Energy Technology Data Exchange (ETDEWEB)

    Garcés, G., E-mail: ggarces@cenim.csic.es [Department of Physical Metallurgy, National Centre for Metallurgical Research CENIM-CSIC, Av. De Gregorio del Amo 8, 28040 Madrid (Spain); Oñorbe, E. [CIEMAT, Division of Structural Materials, Avenida Complutense, 40, 28040 Madrid (Spain); Gan, W. [German Engineering Materials Science Centre at MLZ, Helmholtz-Zentrum Geesthacht, Lichtebergstr. 1, D-85747 Garching (Germany); Máthis, K. [Department of Physics of Materials, Faculty of Mathematics and Physics, Charles University, KeKarlovu 5, 121 16 Praha 2 (Czech Republic); Tolnai, D. [Institute of Materials Research, Helmholtz-Zentrum Geesthacht, Max-Planck-Str. 1, 21502 Geesthacht (Germany); Horváth, K. [Department of Physics of Materials, Faculty of Mathematics and Physics, Charles University, KeKarlovu 5, 121 16 Praha 2 (Czech Republic); Pérez, P.; Adeva, P. [Department of Physical Metallurgy, National Centre for Metallurgical Research CENIM-CSIC, Av. De Gregorio del Amo 8, 28040 Madrid (Spain)

    2017-04-15

    Twinning in extruded AZ31 alloy with a bimodal grain structure is studied under compression along the extrusion direction. This study has combined in-situ measurements during the compression tests by Synchrotron Radiation Diffraction and Acoustic Emission techniques and the evaluation of the microstructure and texture in post-mortem compression samples deformed at different strains. The microstructure of the alloy is characterized by the coexistence of large areas of fine dynamic recrystallized grains and coarse non-recrystallized grains elongated along extrusion direction. Twinning occurs initially in large elongated grains before the macroscopic yield stress which is controlled by the twinning in equiaxed dynamically recrystallized grains. - Highlights: • The AZ31 extruded at low temperature exhibits a bimodal grains structure. • Twinning takes place before macroscopic yielding in coarse non-DRXed grains. • DRXed grains controls the beginning of plasticity in magnesium alloys with bimodal grain structure.

  6. Layered growth model and epitaxial growth structures for SiCAlN alloys

    International Nuclear Information System (INIS)

    Liu Zhaoqing; Ni Jun; Su Xiaoao; Dai Zhenhong

    2009-01-01

    Epitaxial growth structures for (SiC) 1-x (AlN) x alloys are studied using a layered growth model. First-principle calculations are used to determine the parameters in the layered growth model. The phase diagrams of epitaxial growth are given. There is a rich variety of the new metastable polytype structures at x=1/6 ,1/5 ,1/4 ,1/3 , and 1/2 in the layered growth phase diagrams. We have also calculated the electronic properties of the short periodical SiCAlN alloys predicted by our layered growth model. The results show that various ordered structures of (SiC) 1-x (AlN) x alloys with the band gaps over a wide range are possible to be synthesized by epitaxial growth.

  7. Structural characterization of the fusion core in syncytin, envelope protein of human endogenous retrovirus family W

    International Nuclear Information System (INIS)

    Gong Rui; Peng Xiaoxue; Kang Shuli; Feng Huixing; Huang Jianying; Zhang Wentao; Lin Donghai; Tien Po; Xiao Gengfu

    2005-01-01

    Syncytin is a captive retroviral envelope protein, possibly involved in the formation of the placental syncytiotrophoblast layer generated by trophoblast cell fusion at the maternal-fetal interface. We found that syncytin and type I viral envelope proteins shared similar structural profiling, especially in the regions of N- and C-terminal heptad repeats (NHR and CHR). We expressed the predicted regions of NHR (41 aa) and CHR (34 aa) in syncytin as a native single chain (named 2-helix protein) to characterize it. 2-helix protein exists as a trimer and is highly α-helix, thermo-stable, and denatured by low pH. NHR and CHR could form a protease-resistant complex. The complex structure built by the molecular docking demonstrated that NHR and CHR associated in an antiparallel manner. Overall, the 2-helix protein could form a thermo-stable coiled coil trimer. The fusion core structure of syncytin was first demonstrated in endogenous retrovirus. These results support the explanation how syncytin mediates cytotrophoblast cell fusion involved in placental morphogenesis

  8. Influence of structural transition on the electronic structures and physical properties of Ni2MnGa alloy films

    International Nuclear Information System (INIS)

    Kim, K. W.; Kudryavtsev, Y. V.; Rhee, J. Y.; Lee, N. N.; Lee, Y. P.

    2004-01-01

    Ordered and disordered Ni 2 MnGa alloy films were prepared by flash evaporation onto substrates maintained at 720 K and 150 K, respectively. The results show that the ordered films behave in nearly the same way as the bulk Ni 2 MnGa ferromagnetic shape-memory alloy, including the martensitic transformation at 200 K, while the disordered films exhibit characteristics of amorphous alloys. It was also found that the disordering in Ni 2 MnGa alloy films did not change to any appreciable magnetic ordering down to 4 K. Annealing of the disordered films restores the ordered structure with an almost full recovery of the magnetic, magneto-optical and transport properties of the ordered Ni 2 MnGa alloy films. It was also understood, for the first time, how the structural ordering in the films influences the physical properties, including the surprising loss of ferromagnetism in the disordered films, as a result of performing electronic-structure calculations.

  9. 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

  10. Structure and mechanical properties of as-cast Ti-5Nb-xFe alloys

    International Nuclear Information System (INIS)

    Hsu, Hsueh-Chuan; Hsu, Shih-Kuang; Wu, Shih-Ching; Lee, Chih-Jhan; Ho, Wen-Fu

    2010-01-01

    In this study, as-cast Ti-5Nb and a series of Ti-5Nb-xFe alloys were investigated and compared with commercially pure titanium (c.p. Ti) in order to determine their structure and mechanical properties. The series of Ti-5Nb-xFe alloys contained an iron content ranging from 1 to 5 mass% and were prepared by using a commercial arc-melting vacuum-pressure casting system. Additionally, X-ray diffraction (XRD) for phase analysis was conducted with a diffractometer, and three-point bending tests were performed to evaluate the mechanical properties of all specimens. The fractured surfaces were observed by using scanning electron microscopy (SEM). The experimental results indicated that these alloys possessed a range of different structures and mechanical properties dependent upon the various additions of Fe. With an addition of 1 mass% Fe, retention of the metastable β phase began. However, when 4 mass% Fe or greater was added, the β phase was entirely retained with a bcc crystal structure. Moreover, the ω phase was only detected in the Ti-5Nb-2Fe, Ti-5Nb-3Fe and Ti-5Nb-4Fe alloys. The largest quantity of ω phase and the highest bending modulus were found in the Ti-5Nb-3Fe alloy. The Ti-5Nb-2Fe alloy had the lowest bending modulus, which was lower than that of c.p. Ti by 20%. This alloy exhibited the highest bending strength/modulus ratio of 26.7, which was higher than that of c.p. Ti by 214%, and of the Ti-5Nb alloy (14.4 ) by 85%. Additionally, the elastically recoverable angles of the ductile Ti-5Nb-1Fe (19.9 o ) and Ti-5Nb-5Fe (29.5 o ) alloys were greater than that of c.p. Ti (2.7 o ) by as much as 637% and 993%, respectively. Furthermore, the preliminary cell culturing results revealed that the Ti-5Nb-xFe alloys were not only biocompatible, but also supported cell attachment.

  11. Structure and mechanical properties of as-cast Ti-5Nb-xFe alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Hsueh-Chuan; Hsu, Shih-Kuang; Wu, Shih-Ching [Department of Dental Laboratory Technology, Central Taiwan University of Science and Technology, Taichung 40605, Taiwan (China); Institute of Biomedical Engineering and Material Science, Central Taiwan University of Science and Technology, Changhua 51591, Taiwan (China); Lee, Chih-Jhan [Department of Materials Science and Engineering, Da-Yeh University, Changhua 51591, Taiwan (China); Ho, Wen-Fu, E-mail: fujii@mail.dyu.edu.tw [Department of Materials Science and Engineering, Da-Yeh University, Changhua 51591, Taiwan (China)

    2010-09-15

    In this study, as-cast Ti-5Nb and a series of Ti-5Nb-xFe alloys were investigated and compared with commercially pure titanium (c.p. Ti) in order to determine their structure and mechanical properties. The series of Ti-5Nb-xFe alloys contained an iron content ranging from 1 to 5 mass% and were prepared by using a commercial arc-melting vacuum-pressure casting system. Additionally, X-ray diffraction (XRD) for phase analysis was conducted with a diffractometer, and three-point bending tests were performed to evaluate the mechanical properties of all specimens. The fractured surfaces were observed by using scanning electron microscopy (SEM). The experimental results indicated that these alloys possessed a range of different structures and mechanical properties dependent upon the various additions of Fe. With an addition of 1 mass% Fe, retention of the metastable {beta} phase began. However, when 4 mass% Fe or greater was added, the {beta} phase was entirely retained with a bcc crystal structure. Moreover, the {omega} phase was only detected in the Ti-5Nb-2Fe, Ti-5Nb-3Fe and Ti-5Nb-4Fe alloys. The largest quantity of {omega} phase and the highest bending modulus were found in the Ti-5Nb-3Fe alloy. The Ti-5Nb-2Fe alloy had the lowest bending modulus, which was lower than that of c.p. Ti by 20%. This alloy exhibited the highest bending strength/modulus ratio of 26.7, which was higher than that of c.p. Ti by 214%, and of the Ti-5Nb alloy (14.4 ) by 85%. Additionally, the elastically recoverable angles of the ductile Ti-5Nb-1Fe (19.9{sup o}) and Ti-5Nb-5Fe (29.5{sup o}) alloys were greater than that of c.p. Ti (2.7{sup o}) by as much as 637% and 993%, respectively. Furthermore, the preliminary cell culturing results revealed that the Ti-5Nb-xFe alloys were not only biocompatible, but also supported cell attachment.

  12. Special quasirandom structures for binary/ternary group IV random alloys

    KAUST Repository

    Chroneos, Alexander I.

    2010-06-01

    Simulation of defect interactions in binary/ternary group IV semiconductor alloys at the density functional theory level is difficult due to the random distribution of the constituent atoms. The special quasirandom structures approach is a computationally efficient way to describe the random nature. We systematically study the efficacy of the methodology and generate a number of special quasirandom cells for future use. In order to demonstrate the applicability of the technique, the electronic structures of E centers in Si1-xGex and Si1-x -yGexSny alloys are discussed for a range of nearest neighbor environments. © 2010 Elsevier B.V. All rights reserved.

  13. Highlighting micrographic structures of uranium alloys containing 0.5 to 10 per cent wt molybdenum

    International Nuclear Information System (INIS)

    Laniesse, J.; Bouleau, M.

    1959-02-01

    The authors report a study which aimed at determining for different uranium molybdenum alloys and with respect to their molybdenum content a polishing method which allows a relatively simple grain examination in the as-cast condition, an as perfect as possible resolution of eutectic decompositions, and the appropriate conditions to highlight structures (beta-alpha and gamma-alpha martensite transformations, beta phase retention and decomposition, transient structures, eutectoid decomposition, and so on). Alloys differ by their molybdenum content: from 0.5 to 1 per cent wt, 1.5 to 3 per cent wt, 5 to 10 per cent wt

  14. Structure and Mechanical Properties of As-Cast Ti–5Sn–xMo Alloys

    Science.gov (United States)

    Yu, Hsing-Ning; Hsu, Hsueh-Chuan; Wu, Shih-Ching; Hsu, Shih-Kuang; Ho, Wen-Fu

    2017-01-01

    Ti–5Sn–xMo (x = 0, 1, 3, 5, 7.5, 10, 12.5, 15, 17.5, and 20 wt %) alloys were designed and prepared for application as implant materials with superior mechanical properties. The results demonstrated that the crystal structure and mechanical properties of Ti–5Sn–xMo alloys are highly affected by their Mo content. The as-cast microstructures of Ti–5Sn–xMo alloys transformed in the sequence of phases α′ → α″ → β, and the morphologies of the alloys changed from a lath structure to an equiaxed structure as the Mo content increased. The α″-phase Ti–5Sn–7.5Mo (80 GPa) and β-phase Ti–5Sn–10Mo (85 GPa) exhibited relatively low elastic moduli and had excellent elastic recovery angles of 27.4° and 37.8°, respectively. Furthermore, they exhibited high ductility and moderate strength, as evaluated using the three-point bending test. Search for a more suitable implant material by this study, Ti–5Sn–xMo alloys with 7.5 and 10 wt % Mo appear to be promising candidates because they demonstrate the optimal combined properties of microhardness, ductility, elastic modulus, and elastic recovery capability. PMID:28772820

  15. Plasma induced material defects and threshold values for thermal loads in high temperature resistant alloys and in refractory metals for first wall application in fusion reactors

    International Nuclear Information System (INIS)

    Bolt, H.; Hoven, H.; Kny, E.; Koizlik, K.; Linke, J.; Nickel, H.; Wallura, E.

    1986-10-01

    Materials for the application in the first wall of fusion reactors of the tokamak type are subjected to pulsed heat fluxes which range from some 0.5 MW m -2 to 10 MW m -2 during normal plasma operation, and which can exceed 1000 MW m -2 during total plasma disruptions. The structural defects and material fatigue caused by this types of plasma wall interaction are investigated and the results are plotted in threshold loading curves. Additionally, the results are, as far as possible, compared with quantitative, theoretical calculations. These procedures allow a semiquantitative evaluation of the applicability of the mentioned metals in the first wall of fusion reactors. (orig.) [de

  16. Influence of grain structure on quench sensitivity relative to localized corrosion of high strength aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, ShengDan, E-mail: csuliusd@163.com [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Changsha 410083 (China); Li, ChengBo [Light Alloy Research Institute, Central South University, Changsha 410083 (China); Deng, YunLai; Zhang, XinMing [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Changsha 410083 (China)

    2015-11-01

    The influence of grain structure on quench sensitivity relative to localized corrosion of high strength aluminum alloy 7055 was investigated by electrochemical test, accelerated exfoliation corrosion test, optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). The decrease of quench rate led to lower corrosion resistance of both the homogenized and solution heat treated (HS) alloy with equiaxed grains and the hot-rolled and solution heat treated (HRS) alloy with elongated grains, but there was a higher increment in corrosion depth and corrosion current density and a higher decrement in corrosion potential for the latter alloy, which therefore exhibited higher quench sensitivity. It is because in this alloy the larger amount of (sub) grain boundaries led to a higher increment in the amount of quench-induced η phase and precipitates free zone at (sub) grain boundaries with the decrease of quench rate, and there was a larger increment in the content of Zn, Mg and Cu in the η phase at grain boundaries due to slow quenching. The presence of subgrain boundaries in the HRS alloy tended to increase corrosion resistance at high quench rates higher than about 630 °C/min but decrease it at lower quench rates. - Highlights: • (Sub)Grain boundaries increase quench sensitivity relative to localized corrosion. • Subgrain boundaries decrease corrosion resistance below quench rate of 630 °C/min. • More (sub) grain boundaries leads to more GBPs and PFZ with decreasing quench rate.

  17. Structure and properties of Al-Mg-Li-Zr system alloys

    International Nuclear Information System (INIS)

    Fridlyander, I.N.; Dolzhanskij, Yu.M.; Sandler, V.S.; Tyurin, .V.; Nikol'skaya, T.I.

    1977-01-01

    Studied were the structure and mechanical properties of the Al-Mg-Li-Zr alloy system (including 01420 alloy) containing 1.6-5.3%Li and 1.0-8.8%Mg). Electron microscopic studies of 01420 alloy conducted after heating at 450 deg C for 4 hours revealed non-uniformly distributed precipitations of a metastable phase ZrAl 3 , having spherical and needle-like configurations. These precipitations, together with zirconium contained in the solid solution, retard recrystallization. The introduction of 0.1-0.2% Zr decreases the limiting solubility of magnesium and lithium in the aluminium solid solution and leads to the formation of disperse equilibrium (S and, possibly, γ) phases with the size of 0.1-0.5 mcm. These phases were observed in the alloys containing (>=) 4% Mg and 1.9-3.5% Li. The method of planned experiment was used to study the principles governing the variation of the mechanical properties of the alloys subjected to water hardening and after aging at 170 deg C for 16 hours. It was established that the strength properties of the hardened alloys become higher, and the relative elongation decreases with the content of lithium and especially magnesium. It would be more proper to assess strengthening in the course of aging according to variation in the yield point and hardness. The effect of aging determined by the yield point depends on the content of lithium and is practically independent of the concentration of magnesium

  18. A comparative study of ausforming of shape memory alloys with A2 and B2 structures

    International Nuclear Information System (INIS)

    Hornbogen, E.

    1999-01-01

    Ausforming implies plastic deformation of austenite (β) at temperatures T AF M d , at which no stress- or strain-induced transformation can occur. It introduces a variety of extrinsic lattice defects, which in turn modify the course of transformation, the structure of martensite, and increase the conventional strength of the alloys. The temperature range of ausforming has to be subdivided into three subranges, depending on whether the β-phase is (1), disordered; (2), ordered; or (3) capable of precipitation of a second phase or massive transformation. For the Cu-base alloys the ranges 1 and 3, and for Ni-Ti 2 and 3 may apply. This causes a different hot-deformation behavior of the two types of alloys: the formation of dislocation groupings (2-d, 3-d-nets, and Moires) in the brass-type alloys which undergo ordering during cooling from T AF. In addition a particular twinning mechanism and the formation of a rolling texture are found in ordered Ni-Ti. In Ni-Ti-alloys premartensitic R-phase formation can be caused by ausforming. Ausforming leads to lower temperatures but not to suppression of martensitic transformation cycles. Conventional strength is increased in both types of alloys. (orig.)

  19. Mechanistic Insight into Bunyavirus-Induced Membrane Fusion from Structure-Function Analyses of the Hantavirus Envelope Glycoprotein Gc.

    Directory of Open Access Journals (Sweden)

    Pablo Guardado-Calvo

    2016-10-01

    Full Text Available Hantaviruses are zoonotic viruses transmitted to humans by persistently infected rodents, giving rise to serious outbreaks of hemorrhagic fever with renal syndrome (HFRS or of hantavirus pulmonary syndrome (HPS, depending on the virus, which are associated with high case fatality rates. There is only limited knowledge about the organization of the viral particles and in particular, about the hantavirus membrane fusion glycoprotein Gc, the function of which is essential for virus entry. We describe here the X-ray structures of Gc from Hantaan virus, the type species hantavirus and responsible for HFRS, both in its neutral pH, monomeric pre-fusion conformation, and in its acidic pH, trimeric post-fusion form. The structures confirm the prediction that Gc is a class II fusion protein, containing the characteristic β-sheet rich domains termed I, II and III as initially identified in the fusion proteins of arboviruses such as alpha- and flaviviruses. The structures also show a number of features of Gc that are distinct from arbovirus class II proteins. In particular, hantavirus Gc inserts residues from three different loops into the target membrane to drive fusion, as confirmed functionally by structure-guided mutagenesis on the HPS-inducing Andes virus, instead of having a single "fusion loop". We further show that the membrane interacting region of Gc becomes structured only at acidic pH via a set of polar and electrostatic interactions. Furthermore, the structure reveals that hantavirus Gc has an additional N-terminal "tail" that is crucial in stabilizing the post-fusion trimer, accompanying the swapping of domain III in the quaternary arrangement of the trimer as compared to the standard class II fusion proteins. The mechanistic understandings derived from these data are likely to provide a unique handle for devising treatments against these human pathogens.

  20. Design of the segment structure and coolant ducts for a fusion reactor blanket and shield

    International Nuclear Information System (INIS)

    Briaris, D.A.; Stanbridge, J.R.

    1978-05-01

    An outline design and analysis of a support structure for the replaceable first wall of a helium cooled fusion reactor blanket has been undertaken. The proposed structure supports all the segment gravitational loads with maximum deflections limited to < 10 mm, and is itself supported off the outer shield by a simple vee-in-groove arrangement. It is a feature of the design that the coaxial coolant pipes and the segment structure operate at the same temperature, making it possible for them to be integrated, thereby avoiding the necessity for pipe bellows. The requirements of cooling the inner arm of the structure and increasing the major radius of the torus by approximately = 0.5 m, have been identified as problems associated with the 'horseshoe' shaped structure applicable to the reactor with divertor. For a ring structure, i.e. reactor without divertor, these problems do not arise. (author)

  1. Aging Optimization of Aluminum-Lithium Alloy C458 for Application to Cryotank Structures

    Science.gov (United States)

    Sova, B. J.; Sankaran, K. K.; Babel, H.; Farahmand, B.; Rioja, R.

    2003-01-01

    Compared with aluminum alloys such as 2219, which is widely used in space vehicle for cryogenic tanks and unpressurized structures, aluminum-lithium alloys possess attractive combinations of lower density and higher modulus along with comparable mechanical properties. These characteristics have resulted in the successful use of the aluminum-lithium alloy 2195 (Al-1.0 Li-4.0 Cu-0.4 Mg-0.4 Ag-0.12 Zr) for the Space Shuttle External Tank, and the consideration of newer U.S. aluminum-lithium alloys such as L277 and C458 for future space vehicles. These newer alloys generally have lithium content less than 2 wt. % and their composition and processing have been carefully tailored to increase the toughness and reduce the mechanical property anisotropy of the earlier generation alloys such 2090 and 8090. Alloy processing, particularly the aging treatment, has a significant influence on the strength-toughness combinations and their dependence on service environments for aluminum-lithium alloys. Work at NASA Marshall Space Flight Center on alloy 2195 has shown that the cryogenic toughness can be improved by employing a two-step aging process. This is accomplished by aging at a lower temperature in the first step to suppress nucleation of the strengthening precipitate at sub-grain boundaries while promoting nucleation in the interior of the grains. Second step aging at the normal aging temperature results in precipitate growth to the optimum size. A design of experiments aging study was conducted for plate. To achieve the T8 temper, Alloy C458 (Al-1.8 Li-2.7 Cu-0.3 Mg- 0.08 Zr-0.3 Mn-0.6 Zn) is typically aged at 300 F for 24 hours. In this study, a two-step aging treatment was developed through a comprehensive 24 full factorial design of experiments study and the typical one-step aging used as a reference. Based on the higher lithium content of C458 compared with 2195, the first step aging temperature was varied between 175 F and 250 F. The second step aging temperatures was

  2. Structural and magnetic properties of FeCoC system obtained by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Rincón Soler, A. I. [Universidad Tecnológica de Pereira, Fac. de Ciencias, Depto. de Física (Colombia); Rodríguez Jacobo, R. R., E-mail: rrrodriguez@uao.edu.co [Universidad Autónoma de Occidente, Fac. de Ciencias Básicas, Depto. de Física (Colombia); Medina Barreto, M. H.; Cruz-Muñoz, B. [Universidad Tecnológica de Pereira, Fac. de Ciencias, Depto. de Física (Colombia)

    2017-11-15

    Fe{sub 96−X}Co{sub X}C{sub 4} (x = 0, 10, 20, 30, 40 at. %) alloys were obtained by mechanical alloying of Fe, C and Co powders using high-energy milling. The structural and magnetic properties of the alloy system were analyzed by X-ray diffraction, Scanning Electron Microscopy (SEM), Vibrating Sample Magnetometer (VSM) and Mössbauer Spectrometry at room temperature. The X-ray diffraction patterns showed a BCC-FeCoC structure phase for all samples, as well as a lattice parameter that slightly decreases with Co content. The saturation magnetization and coercive field were analyzed as a function of Co content. The Mössbauer spectra were fitted with a hyperfine magnetic field distribution showing the ferromagnetic behavior and the disordered character of the samples. The mean hyperfine magnetic field remained nearly constant (358 T) with Co content.

  3. Computation material science of structural-phase transformation in casting aluminium alloys

    Science.gov (United States)

    Golod, V. M.; Dobosh, L. Yu

    2017-04-01

    Successive stages of computer simulation the formation of the casting microstructure under non-equilibrium conditions of crystallization of multicomponent aluminum alloys are presented. On the basis of computer thermodynamics and heat transfer during solidification of macroscale shaped castings are specified the boundary conditions of local heat exchange at mesoscale modeling of non-equilibrium formation the solid phase and of the component redistribution between phases during coalescence of secondary dendrite branches. Computer analysis of structural - phase transitions based on the principle of additive physico-chemical effect of the alloy components in the process of diffusional - capillary morphological evolution of the dendrite structure and the o of local dendrite heterogeneity which stochastic nature and extent are revealed under metallographic study and modeling by the Monte Carlo method. The integrated computational materials science tools at researches of alloys are focused and implemented on analysis the multiple-factor system of casting processes and prediction of casting microstructure.

  4. Effect of Nanosheet Surface Structure of Titanium Alloys on Cell Differentiation

    Directory of Open Access Journals (Sweden)

    Satoshi Komasa

    2014-01-01

    Full Text Available Titanium alloys are the most frequently used dental implants partly because of the protective oxide coating that spontaneously forms on their surface. We fabricated titania nanosheet (TNS structures on titanium surfaces by NaOH treatment to improve bone differentiation on titanium alloy implants. The cellular response to TNSs on Ti6Al4V alloy was investigated, and the ability of the modified surfaces to affect osteogenic differentiation of rat bone marrow cells and increase the success rate of titanium implants was evaluated. The nanoscale network structures formed by alkali etching markedly enhanced the functions of cell adhesion and osteogenesis-related gene expression of rat bone marrow cells. Other cell behaviors, such as proliferation, alkaline phosphatase activity, osteocalcin deposition, and mineralization, were also markedly increased in TNS-modified Ti6Al4V. Our results suggest that titanium implants modified with nanostructures promote osteogenic differentiation, which may improve the biointegration of these implants into the alveolar bone.

  5. Structural and magnetic properties of FeCoC system obtained by mechanical alloying

    International Nuclear Information System (INIS)

    Rincón Soler, A. I.; Rodríguez Jacobo, R. R.; Medina Barreto, M. H.; Cruz-Muñoz, B.

    2017-01-01

    Fe 96−X Co X C 4 (x = 0, 10, 20, 30, 40 at. %) alloys were obtained by mechanical alloying of Fe, C and Co powders using high-energy milling. The structural and magnetic properties of the alloy system were analyzed by X-ray diffraction, Scanning Electron Microscopy (SEM), Vibrating Sample Magnetometer (VSM) and Mössbauer Spectrometry at room temperature. The X-ray diffraction patterns showed a BCC-FeCoC structure phase for all samples, as well as a lattice parameter that slightly decreases with Co content. The saturation magnetization and coercive field were analyzed as a function of Co content. The Mössbauer spectra were fitted with a hyperfine magnetic field distribution showing the ferromagnetic behavior and the disordered character of the samples. The mean hyperfine magnetic field remained nearly constant (358 T) with Co content.

  6. Computer generated structures of grain boundaries in Li2-type ordered alloys

    International Nuclear Information System (INIS)

    DeHosson, J.Th.M.; Pestman, B.J.; Schapink, F.W.; Tichelaar, F.D.

    1988-01-01

    In recent years, the influence of the establishment of long-range order in cubic alloys on the structure of grain boundaries in Li 2 alloys has been considered. Thus, for example, for the Σ = 5 (310) tilt boundary the various possible structures have been investigated that are generated upon ordering, starting from plausible structures in the disordered state. However, apart from some rough energy estimates based upon nearest neighbor interactions, no reliable energy calculations have been performed of these different possible structures. In this paper, computer calculations based upon interatomic pair potentials constructed in such a way that the Li 2 structure is stable with respect to disordering, are reported for the Σ = 5 (310) boundary. The relative stability of various possible structures, with associated different boundary compositions, has been investigated

  7. Formation of metastable phases and nanocomposite structures in rapidly solidified Al-Fe alloys

    International Nuclear Information System (INIS)

    Nayak, S.S.; Chang, H.J.; Kim, D.H.; Pabi, S.K.; Murty, B.S.

    2011-01-01

    Highlights: → Structures of nanocomposites in rapidly solidified Al-Fe alloys were investigated. → Nanoquasicrystalline, amorphous and intermetallics phases coexist with α-Al. → Nanoquasicrystalline phase was observed for the first time in the dilute Al alloys. → Thermodynamic driving force plays dominant role in precipitation of Fe-rich phases. → High hardness (3.57 GPa) was observed for nanocomposite of Al-10Fe alloy. - Abstract: In the present work the structure and morphology of the phases of nanocomposites formed in rapidly solidified Al-Fe alloys were investigated in details using analytical transmission electron microscopy and X-ray diffraction. Nanoquasicrystalline phases, amorphous phase and intermetallics like Al 5 Fe 2 , Al 13 F 4 coexisted with α-Al in nanocomposites of the melt spun alloys. It was seen that the Fe supersaturation in α-Al diminished with the increase in Fe content and wheel speed indicating the dominant role of the thermodynamic driving force in the precipitation of Fe-rich phases. Nanoquasicrystalline phases were observed for the first time in the dilute Al alloys like Al-2.5Fe and Al-5Fe as confirmed by high resolution TEM. High hardness (3.57 GPa) was measured in nanocomposite of Al-10Fe alloy, which was attributed to synergistic effect of solid solution strengthening due to high solute content (9.17 at.% Fe), dispersion strengthening by high volume fraction of nanoquasicrystalline phase; and Hall-Petch strengthening from finer cell size (20-30 nm) of α-Al matrix.

  8. Fusion-fission probabilities, cross sections, and structure notes of superheavy nuclei

    International Nuclear Information System (INIS)

    Kowal, Michał; Cap, Tomasz; Jachimowicz, Piotr; Skalski, Janusz; Siwek-Wilczyńska, Krystyna; Wilczyński, Janusz

    2016-01-01

    Fusion – fission probabilities in the synthesis of heaviest elements are discussed in the context of the latest experimental reports. Cross sections for superheavy nuclei are evaluated using the “Fusion by Diffusion” (FBD) model. Predictive power of this approach is shown for experimentally known Lv and Og isotopes and predictions given for Z = 119, 120. Ground state and saddle point properties as masses, shell corrections, pairing energies, and deformations necessary for cross-section estimations are calculated systematically within the multidimensional microscopic-macroscopic method based on the deformed Woods-Saxon single-particle potential. In the frame of the FBD approach predictions for production of elements heavier than Z = 118 are not too optimistic. For this reason, and because of high instability of superheavy nuclei, we comment on some structure effects, connected with the K-isomerism phenomenon which could lead to a significant increase in the stability of these systems.

  9. Low Resolution Structure of RAR1-GST-Tag Fusion Protein in Solution

    International Nuclear Information System (INIS)

    Taube, M.; Kozak, M.; Jarmolowski, A.

    2010-01-01

    RAR1 is a protein required for resistance mediated by many R genes and function upstream of signaling pathways leading to H 2 O 2 accumulation. The structure and conformation of RAR1-GST-Tag fusion protein from barley (Hordeum vulgare) in solution was studied by the small angle scattering of synchrotron radiation. It was found that the dimer of RAR1-GST-Tag protein is characterized in solution by radius of gyration R G = 6.19 nm and maximal intramolecular vector D max = 23 nm. On the basis of the small angle scattering of synchrotron radiation SAXS data two bead models obtained by ab initio modeling are proposed. Both models show elongated conformations. We also concluded that molecules of fusion protein form: dimers in solution via interaction of GST domains. (authors)

  10. Structural design considerations in the Mirror Fusion Test Facility (MFTF-B) vacuum vessel

    International Nuclear Information System (INIS)

    Vepa, K.; Sterbentz, W.H.

    1981-01-01

    In view of favorable results from the Tandem Mirror Experiment (TMX) also at LLNL, the MFTF project is now being rescoped into a large tandem mirror configuration (MFTF-B), which is the mainline approach to a mirror fusion reactor. This paper concerns itself with the structural aspects of the design of the vessel. The vessel and its intended functions are described. The major structural design issues, especially those influenced by the analysis, are described. The objectives of the finite element analysis and their realization are discussed at length

  11. Radiation induced structural changes in alpha-copper-zinc alloys

    International Nuclear Information System (INIS)

    Schuele, W.; Gieb, M.

    1991-01-01

    During irradiation of alpha-copper-zinc alloys with high energy electrons and protons a decrease of the electrical resistivity due to an increase of the degree of short range order is observed through radiation enhanced diffusion followed by an increase of the electrical resistivity through the formation of radiation induced interstitial clusters. The initial formation rate of interstitial clusters increases about linearly with the displacement rate for electron and proton irradiation. The largest initial formation rate is found between 60 and 130 0 C becoming negligibly small above 158 0 C and decreases drastically below 60 0 C. The dynamic steady state interstitial cluster concentration increases with decreasing irradiation temperature in the investigated temperature range between 158 and 40 0 C. Above 158 0 C the formation rate of interstitial clusters is negligibly small. Thus the transition temperature for radiation induced interstitial cluster formation is 158 0 C, depending mainly on the migration activation energy of vacancies. The radiation induced interstitial clusters are precipitates in those alloys in which the diffusion rate of the undersized component atoms via an interstitialcy diffusion mechanism is larger than that of the other atoms

  12. Phonon structures of GaN-based random semiconductor alloys

    Science.gov (United States)

    Zhou, Mei; Chen, Xiaobin; Li, Gang; Zheng, Fawei; Zhang, Ping

    2017-12-01

    Accurate modeling of thermal properties is strikingly important for developing next-generation electronics with high performance. Many thermal properties are closely related to phonon dispersions, such as sound velocity. However, random substituted semiconductor alloys AxB1-x usually lack translational symmetry, and simulation with periodic boundary conditions often requires large supercells, which makes phonon dispersion highly folded and hardly comparable with experimental results. Here, we adopt a large supercell with randomly distributed A and B atoms to investigate substitution effect on the phonon dispersions of semiconductor alloys systematically by using phonon unfolding method [F. Zheng, P. Zhang, Comput. Mater. Sci. 125, 218 (2016)]. The results reveal the extent to which phonon band characteristics in (In,Ga)N and Ga(N,P) are preserved or lost at different compositions and q points. Generally, most characteristics of phonon dispersions can be preserved with indium substitution of gallium in GaN, while substitution of nitrogen with phosphorus strongly perturbs the phonon dispersion of GaN, showing a rapid disintegration of the Bloch characteristics of optical modes and introducing localized impurity modes. In addition, the sound velocities of both (In,Ga)N and Ga(N,P) display a nearly linear behavior as a function of substitution compositions. Supplementary material in the form of one pdf file available from the Journal web page at http://https://doi.org/10.1140/epjb/e2017-80481-0.

  13. Electrochemical alloying of immiscible Ag and Co for their structural and magnetic analyses

    Energy Technology Data Exchange (ETDEWEB)

    Santhi, Kalavathy [Material Science Centre, Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai 600025 (India); Department of Physics, Women’s Christian College, Chennai 600006 (India); Kumarsan, Dhanapal [Material Science Centre, Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai 600025 (India); Vengidusamy, Naryanan [Department of Inorganic Chemistry, University of Madras, Guindy Campus, Chennai 600025 (India); Arumainathan, Stephen, E-mail: stephen_arum@hotmail.com [Material Science Centre, Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai 600025 (India)

    2017-07-01

    Highlights: • Ag-Co alloy has been prepared using pulsed electrodeposition method. • Wide range of Ag composition in the alloy was obtained. • XPS measurement evident the Ag and Co in metallic nature. • The electrodeposition method develop dendrite like morphology. • Detailed analysis of magnetic behaviour is carried out. - Abstract: Electrochemical alloying of immiscible Ag and Co was carried out at different current densities from electrolytes of two different concentrations, after optimizing the electrolytic bath and operating conditions. The samples obtained were characterized using X-ray diffraction to confirm the simultaneous deposition of Ag and Co and to determine their crystallographic structure. The atomic percentage of Ag and Co contents in the granular alloy was determined by ICP-OES analysis. The XPS spectra were observed to confirm the presence of Ag and Co in the metallic form in the granular alloy samples. The micrographs observed using scanning and transmission electron microscopes threw light on the surface morphology and the size of the particles. The magnetic nature of the samples was analyzed at room temperature by a vibration sample magnetometer. Their magnetic phase transition while heating was also studied to provide further evidence for the magnetic behaviour and the structure of the deposits.

  14. The complex structure of liquid Cu{sub 6}Sn{sub 5} alloy

    Energy Technology Data Exchange (ETDEWEB)

    Qin Jingyu; Gu Tingkun; Bian Xiufang [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Southern Campus, Jinan 250061 (China); Liu Hui [Shandong High Performance Computing Center, Shandong University, Southern Campus, Jinan 250061 (China)

    2009-04-15

    By applying ab initio molecular dynamics simulation to liquid Cu{sub 6}Sn{sub 5} alloy, the hetero-coordination tendency is discovered by Bathia-Thornton partial correlation functions and a chemical short-range parameter. However the local structural environment of Sn in l-Cu{sub 6}Sn{sub 5} alloy resembles that of liquid Sn by Voronoi analysis. A new feature, i.e. a subpeak in between the first and second peaks, is discovered by the present method which implies that topologically disordered {beta}-Sn-type structural units may exist in l-Cu{sub 6}Sn{sub 5} alloy. The local density states of electrons show that both Cu-Sn and Sn-Sn bonding exist in l-Cu{sub 6}Sn{sub 5} alloy. This work suggests that chemical short-range order between unlike atoms and self-coordination between Sn atoms coexists in l-Cu{sub 6}Sn{sub 5} alloy.

  15. Electrochemical alloying of immiscible Ag and Co for their structural and magnetic analyses

    International Nuclear Information System (INIS)

    Santhi, Kalavathy; Kumarsan, Dhanapal; Vengidusamy, Naryanan; Arumainathan, Stephen

    2017-01-01

    Highlights: • Ag-Co alloy has been prepared using pulsed electrodeposition method. • Wide range of Ag composition in the alloy was obtained. • XPS measurement evident the Ag and Co in metallic nature. • The electrodeposition method develop dendrite like morphology. • Detailed analysis of magnetic behaviour is carried out. - Abstract: Electrochemical alloying of immiscible Ag and Co was carried out at different current densities from electrolytes of two different concentrations, after optimizing the electrolytic bath and operating conditions. The samples obtained were characterized using X-ray diffraction to confirm the simultaneous deposition of Ag and Co and to determine their crystallographic structure. The atomic percentage of Ag and Co contents in the granular alloy was determined by ICP-OES analysis. The XPS spectra were observed to confirm the presence of Ag and Co in the metallic form in the granular alloy samples. The micrographs observed using scanning and transmission electron microscopes threw light on the surface morphology and the size of the particles. The magnetic nature of the samples was analyzed at room temperature by a vibration sample magnetometer. Their magnetic phase transition while heating was also studied to provide further evidence for the magnetic behaviour and the structure of the deposits.

  16. Membranes linked by trans-SNARE complexes require lipids prone to non-bilayer structure for progression to fusion.

    Science.gov (United States)

    Zick, Michael; Stroupe, Christopher; Orr, Amy; Douville, Deborah; Wickner, William T

    2014-01-01

    Like other intracellular fusion events, the homotypic fusion of yeast vacuoles requires a Rab GTPase, a large Rab effector complex, SNARE proteins which can form a 4-helical bundle, and the SNARE disassembly chaperones Sec17p and Sec18p. In addition to these proteins, specific vacuole lipids are required for efficient fusion in vivo and with the purified organelle. Reconstitution of vacuole fusion with all purified components reveals that high SNARE levels can mask the requirement for a complex mixture of vacuole lipids. At lower, more physiological SNARE levels, neutral lipids with small headgroups that tend to form non-bilayer structures (phosphatidylethanolamine, diacylglycerol, and ergosterol) are essential. Membranes without these three lipids can dock and complete trans-SNARE pairing but cannot rearrange their lipids for fusion. DOI: http://dx.doi.org/10.7554/eLife.01879.001.

  17. Effect of scandium on structure and hardening of Al–Ca eutectic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Belov, N.A., E-mail: nikolay-belov@yandex.ru [National Research and Technological University “MISIS”, 4, Leninsky pr., Moscow 119049 (Russian Federation); Naumova, E.A. [Bauman Moscow State Technical University, 5, 2 ul. Baumanskaya, Moscow, 105005 (Russian Federation); Alabin, A.N. [National Research and Technological University “MISIS”, 4, Leninsky pr., Moscow 119049 (Russian Federation); UC RUSAL, 13/1, Nikoloyamskaya st., Moscow, 109240 (Russian Federation); Matveeva, I.A. [UC RUSAL, 13/1, Nikoloyamskaya st., Moscow, 109240 (Russian Federation)

    2015-10-15

    The phase composition, structure and hardening of alloys in the aluminium corner of the Al–Ca–Sc system were studied in the range up to 10% Ca and up to 1% S≿. The experimental study (optical, scanning and transmission electron microscopy with electron-microprobe analysis, differential thermal analysis and hardness measurements) was combined with Thermo-Calc software simulation for the optimization of the alloy composition. It was shown that only phases of the binary systems (Al{sub 4}Ca and Al{sub 3}Sc) might be in equilibrium with the aluminium solid solution. It was shown that the (Al) + Al{sub 4}Ca eutectic had a much finer structure as compared with the Al–Si eutectic, which suggests a possibility of reaching higher mechanical properties as compared to commercial alloys of the A356 type. The influence of the annealing temperature within the range up to 600 °C on the structure and hardness of the Al–Ca–Sc experimental alloys was studied. It was determined that the maximum hardening corresponded to the annealing at 300 °C, which was due to the precipitation of Al{sub 3}Sc nanoparticles with their further coarsening. With an example of an Al-7.6% Ca-0.3% Sc model experimental alloy, a principal possibility of manufacturing aluminium casting alloys based on the (Al) + Al{sub 4}Ca eutectic was demonstrated. Unlike commercial alloys of the A356 type, the model alloy does not require quenching, as hardening particles are formed in the course of annealing of casting. - Highlights: • Al–Ca–Sc phase diagram in aluminum corner. • Formation of Al{sub 3}Sc nanoparticles in eutectic (Al) + Al{sub 4}Ca during heating at 300–450 °C. • Hardening and thermal stability of proposed (Al–Ca–Sc) and commercial (Al–Si–Mg, 356 type) eutectic alloys.

  18. Structure and stacking faults in layered Mg-Zn-Y alloys: A first-principles study

    International Nuclear Information System (INIS)

    Datta, Aditi; Waghmare, U.V.; Ramamurty, U.

    2008-01-01

    We use first-principles density functional theory total energy calculations based on pseudo-potentials and plane-wave basis to assess stability of the periodic structures with different stacking sequences in Mg-Zn-Y alloys. For pure Mg, we find that the 6-layer (6l) structure with the ABACAB stacking is most stable after the lowest energy hcp (2l) structure with ABAB stacking. Addition of 2 at.% Y leads to stabilization of the structure to 6l sequence whereas the addition of 2 at.% Zn makes the 6l energetically comparable to that of the hcp. Stacking fault (SF) on the basal plane of 6l structure is higher in energy than that of the hcp 2l Mg, which further increases upon Y doping and decreases significantly with Zn doping. SF energy surface for the prismatic slip indicates activation of non-basal slip in alloys with a 6l structure. Charge density analysis shows that the 2l and 6l structures are electronically similar which might be a cause for better stability of 6l structure over a 4l sequence or other periodic structures. Thus, in an Mg-Zn-Y alloy, Y stabilizes the long periodicity, while its mechanical properties are further improved due to Zn doping

  19. Magnetic structure at the surface of a FeZrB alloy

    International Nuclear Information System (INIS)

    Pavuk, M.; Miglierini, M.; Sitek, J.

    2013-01-01

    The aim of this work was to examine two structural states of the "5"7Fe_9_0Zr_7B_3 alloy from the point of view of their domain structure. As the method for obtaining the image of a domain structure we used the magnetic force microscopy (MFM). Its advantage is that besides the image of a domain structure, it also records the image of topography. Another advantage is the high spatial resolution. From both of these advantages, one can benefit in the study of nanocrystalline alloys. Nevertheless, the use of MFM in the study of nanocrystalline materials is so far only rare. Additional structural characterization was obtained by the help of Conversion Electron Moessbauer Spectrometry (CEMS). (authors)

  20. Annealing effects on structure and mechanical properties of CoCrFeNiTiAlx high-entropy alloys

    International Nuclear Information System (INIS)

    Zhang, K B; Fu, Z Y; Zhang, J Y; Wang, W M; Lee, S W; Niihara, K

    2011-01-01

    Novel CoCrFeNiTiAl x (x:molar ratio, other elements are equimolar) high-entropy alloys were prepared by vacuum arc melting and these alloys were subsequently annealed at 1000 deg. C for 2 h. The annealing effects on structure and mechanical properties were investigated. Compared with the as-cast alloys, there are many complex intermetallic phases precipitated from the solid solution matrix in the as-annealed alloys with Al content lower than Al 1.0 . Only simple BCC solid solution structure appears in the as-annealed Al 1.5 and Al 2.0 alloys. This kind of alloys exhibit high resistance to anneal softening. Most as-annealed alloys possess even higher Visker hardness than the as-cast ones. The as-annealed Al 0.5 alloys shows the highest compressive strength while the Al 0 alloy exhibits the best ductility, which is about 2.6 GPa and 13%, respectively. The CoCrFeNiTiAl x high-entropy alloys possess integrated high temperature mechanical property as well.

  1. He bubble sites in implanted copper alloy

    International Nuclear Information System (INIS)

    Moreno, D.; Eliezer, D.

    1996-01-01

    Structural materials in fusion reactors will be exposed to helium implantation over a broad range of energies. The deformation and partial exfoliation of surface layers due to hydrogen isotopes and helium contribute to the total erosion of the first wall. For this reason, one of the most important criteria in the choice of materials for the first wall of fusion reactors is the material's damage resistance. Recent advances in developing nuclear fusion reactors reveal that efficient heat removal from plasma-facing components is very important. Copper and copper alloys are considered an attractive choice for transporting such a high heat flux without thermal damage as they have high thermal conductivity. In the present study the authors report on the structural changes in a copper alloy, due to the helium implantation on the very near surface area, observed by transmission electron microscopy

  2. Atomic structure of the SbCu surface alloy: A surface X-ray diffraction study

    DEFF Research Database (Denmark)

    Meunier, I.; Gay, J.M.; Lapena, L.

    1999-01-01

    The dissolution at 400 degrees C of an antimony layer deposited at room temperature on a Cu(111) substrate leads to a surface alloy with a p(root 3x root 3)R 30 degrees x 30 degrees superstructure and a Sb composition of 1/3.We present here a structural study of this Sb-Cu compound by surface X...

  3. Experimental simulation techniques for the evaluation of structural changes in metals and alloys

    International Nuclear Information System (INIS)

    Lucki, Georgi

    1992-01-01

    In this work, high-doses irradiation in nuclear reactor were simulated using a cyclotron in order to study mechanical, electric, magnetic and structural changes in materials. Results of such simulations for portland cement, binary alloys and stainless steels are presented and discussed. 15 refs., 11 figs., 1 tab

  4. Structure and properties of an aluminium alloy welded by electron beam

    International Nuclear Information System (INIS)

    Ruzimov, Sh.M.; Palvanov, S.R.; Pogrebnjak, A.D.

    2005-01-01

    Full text: In the given work the experimental results on research of influence of electronic beams on structure of an aluminum alloy are submitted. As a basis of samples the alloy Al-Mg-Zn-Cu by the additives Se-0.5 % and Nb-0.15 % is chosen. Samples from a cast aluminum alloy by thickness of 3 mm such as B-96 were welded with an electronic beam in three different modes at radius circle of a root of a welded seam of 5 mm. The welding was carried out by an alloy Amg 63 and Sv-1571 with application electron team welding joint of parts. The basic influence on the given process makes energy - allocation of an electronic beam. For research of phase structure used of X-ray beams (XRD), DRON-2 in copper K α - Cu measurement. For research of structure and morphology of a surface used optical microscope with increase 800-1500 times and electronic microscope with the microanalysis. On figures of optical microscopy the morphology of a seam sharply differs from morphology of an initial part. The microanalysis carried out with a place of a seam, has shown presence of the whole spectrum of elements, such as, Al; Zn; Na; Mg; Cu; and Mn. All measurements carried out in welding zone and in frontier zones that it was possible to carry out the comparative analysis. The element structure of these zones essentially differs in dependence of a condition of welding

  5. Change of structure and some mechanical properties during processing of AlMn(Fe,Si) alloys

    International Nuclear Information System (INIS)

    Kovacs-Csetenyi, E.; Griger, A.; Turmezey, T.; Suchanek, V.

    1990-01-01

    The aim of this work was to study the change of structure and some mechanical properties during processing of AlMn(Fe,Si) alloys. An emphasis was given to the effect of Fe and Si on the properties measured in deformed and annealed states, because of its technological importance

  6. Alloy Dependence of Electron-Phonon Interactions in Double Barrier Structures

    National Research Council Canada - National Science Library

    Wallis, Corinne

    1996-01-01

    ...)As double barrier structures as a function of the alloy concentration in the barrier. We have measured current-voltage and conductance-voltage curves associated with phonon-assisted tunneling with magnetic fields from 0 to 6.8 Tesla...

  7. Fusion reactor materials

    International Nuclear Information System (INIS)

    Sethi, V.K.; Scholz, R.; Nolfi, F.V. Jr.; Turner, A.P.L.

    1980-01-01

    Data are given for each of the following areas: (1) effects of irradiation on fusion reactor materials, (2) hydrogen permeation and materials behavior in alloys, (3) carbon coatings for fusion applications, (4) surface damage of TiB 2 coatings under energetic D + and 4 He + irradiations, and (5) neutron dosimetry

  8. Structure and properties of a splat cooled 2024 aluminum alloy

    Science.gov (United States)

    Lebo, M.; Grant, N. J.

    1974-01-01

    In the investigation the alloy was melted, heated to 750 C, and atomized into fine droplets. The droplets were rapidly quenched against a heavy copper disk rotating at 1725 rpm. The resultant splat cooled flakes were screened. Three flake sizes were finally separated. Flakes of each size were separately processed. The characteristics of the splat cooling process and the properties of the obtained products are discussed. Splat cooling against a metallic substrate permits cooling rates up to about 1,000,000 deg C/sec. Increases in yield strength and tensile strength of 14 to 19% are observed for the splat products. Other improvements are connected with increases in fatigue life and stress rupture performance.

  9. Cellular Shape Memory Alloy Structures: Experiments & Modeling (Part 1)

    Science.gov (United States)

    2012-08-01

    High -­‐ temperature  SMAs 24 Braze  Joint  between  two  wrought  pieces  of  a  Ni24.5Pd25Ti50.5  HTSMA   (HTSMA  from...process  can  be  used   to  join  other  metal  alloys  and   high -­‐ temperature   SMAs 25 Cellular  Shape  Memory...20 30 40 50 60 910 3 4 8 5 2 T (°C) Shape memory & superelasticity 1 0 e (%) (GPa) 6 7 A NiTi wire

  10. Correlation between potential well structure and neutron production in inertial electrostatic confinement fusion

    International Nuclear Information System (INIS)

    Ohnishi, M.; Yamamoto, Y.; Yoshikawa, K.; Sato, K.H.

    1997-01-01

    The electrostatic potential well in inertial electrostatic confinement (IEC) is studied using two approaches. First, the equilibrium potential profile is obtained by solving the charge neutrality condition, i.e. n i n e , assuming the appropriate distribution functions for the ions and the electrons. The formation of a double well structure is demonstrated, with a depth depending upon the ratio between the focus radii of the electrons and the ions. The correlations between the well depth and the volume integrated neutron production due to deuterium-deuterium (DD) reactions are obtained. Second, in order to study the stability of the well, the dynamic behaviours of the potential well are calculated by performing time advancing numerical simulations on the basis of the particle in cell method. Single, double and triple wells, depending on the amount of injected ion current, are observed to be formed for ions with a monoenergetic distribution. The well in the centre of the multiwell structure is unstable and oscillates with a periods much longer than the inverse ion plasma frequency. A double well structure can be formed even for ions with a spread out energy distribution when the ion current is larger than the threshold value. The time averaged neutron production by DD fusion events is proportional to a power of the ion current involved in forming the double well structure. The results strongly suggest that the high neutron production rate should be attributed to not only the well depth but also the unstable behaviour of the potential, i.e. the intermittent peaking of the density in the centre region. A numerical simulation reveals that IEC possesses a favourable dependence of fusion reactions on the injected ion current for the application to a neutron source or a fusion reactor. (author). 9 refs, 9 figs

  11. Comprehending the structure of a vacuum vessel and in-vessel components of fusion machines. 1. Comprehending the vacuum vessel structure

    International Nuclear Information System (INIS)

    Onozuka, Masanori; Nakahira, Masataka

    2006-01-01

    The functions, conditions and structure of vacuum vessel using tokamak fusion machines are explained. The structural standard and code of vacuum vessel, process of vacuum vessel design, and design of ITER vacuum vessel are described. Production and maintenance of ultra high vacuum, confinement of radioactive materials, support of machines in vessel and electromagnetic force, radiation shield, plasma vertical stability, one-turn electric resistance, high temperature baking heat and remove of nuclear heat, reduce of troidal ripple, structural standard, features of safety of nuclear fusion machines, subjects of structural standard of fusion vacuum vessel, design flow of vacuum vessel, establishment of radial build, selections of materials, baking and cooling method, basic structure, structure of special parts, shield structure, and of support structure, and example of design of structure, ITER, are stated. (S.Y.)

  12. Crystal structure of the conserved herpesvirus fusion regulator complex gH—gL

    Energy Technology Data Exchange (ETDEWEB)

    Chowdary, Tirumala K.; Cairns, Tina M.; Atanasiu, Doina; Cohen, Gary H.; Eisenberg, Roselyn J.; Heldwein, Ekaterina E. [UPENN; (Tufts-MED)

    2015-02-09

    Herpesviruses, which cause many incurable diseases, infect cells by fusing viral and cellular membranes. Whereas most other enveloped viruses use a single viral catalyst called a fusogen, herpesviruses, inexplicably, require two conserved fusion-machinery components, gB and the heterodimer gH–gL, plus other nonconserved components. gB is a class III viral fusogen, but unlike other members of its class, it does not function alone. We determined the crystal structure of the gH ectodomain bound to gL from herpes simplex virus 2. gH–gL is an unusually tight complex with a unique architecture that, unexpectedly, does not resemble any known viral fusogen. Instead, we propose that gH–gL activates gB for fusion, possibly through direct binding. Formation of a gB–gH–gL complex is critical for fusion and is inhibited by a neutralizing antibody, making the gB–gH–gL interface a promising antiviral target.

  13. Crystal Structure of the Conserved Herpes Virus Fusion Regulator Complex gH–gL

    Energy Technology Data Exchange (ETDEWEB)

    Chowdary, T.; Cairns, T; Atanasiu, D; Cohen, G; Eisenberg, R; Heldwein, E

    2010-01-01

    Herpesviruses, which cause many incurable diseases, infect cells by fusing viral and cellular membranes. Whereas most other enveloped viruses use a single viral catalyst called a fusogen, herpesviruses, inexplicably, require two conserved fusion-machinery components, gB and the heterodimer gH-gL, plus other nonconserved components. gB is a class III viral fusogen, but unlike other members of its class, it does not function alone. We determined the crystal structure of the gH ectodomain bound to gL from herpes simplex virus 2. gH-gL is an unusually tight complex with a unique architecture that, unexpectedly, does not resemble any known viral fusogen. Instead, we propose that gH-gL activates gB for fusion, possibly through direct binding. Formation of a gB-gH-gL complex is critical for fusion and is inhibited by a neutralizing antibody, making the gB-gH-gL interface a promising antiviral target.

  14. Crystal structure of the conserved herpes virus fusion regulator complex gH-gL

    Energy Technology Data Exchange (ETDEWEB)

    Chowdary, Tirumala K; Cairns, Tina M; Atanasiu, Doina; Cohen, Gary H; Eisenberg, Roselyn J; Heldwein, Ekaterina E [UPENN; (Tufts-MED)

    2010-09-13

    Herpesviruses, which cause many incurable diseases, infect cells by fusing viral and cellular membranes. Whereas most other enveloped viruses use a single viral catalyst called a fusogen, herpesviruses, inexplicably, require two conserved fusion-machinery components, gB and the heterodimer gH-gL, plus other nonconserved components. gB is a class III viral fusogen, but unlike other members of its class, it does not function alone. We determined the crystal structure of the gH ectodomain bound to gL from herpes simplex virus 2. gH-gL is an unusually tight complex with a unique architecture that, unexpectedly, does not resemble any known viral fusogen. Instead, we propose that gH-gL activates gB for fusion, possibly through direct binding. Formation of a gB-gH-gL complex is critical for fusion and is inhibited by a neutralizing antibody, making the gB-gH-gL interface a promising antiviral target.

  15. A Fundamental Approach to Developing Aluminium based Bulk Amorphous Alloys based on Stable Liquid Metal Structures and Electronic Equilibrium - 154041

    Science.gov (United States)

    2017-03-28

    AFRL-AFOSR-JP-TR-2017-0027 A Fundamental Approach to Developing Aluminium -based Bulk Amorphous Alloys based on Stable Liquid-Metal Structures and...to 16 Dec 2016 4.  TITLE AND SUBTITLE A Fundamental Approach to Developing Aluminium -based Bulk Amorphous Alloys based on Stable Liquid-Metal...Air Force Research Laboratory for accurately predicting compositions of new amorphous alloys specifically based on aluminium with properties superior

  16. Morphology, deformation, and defect structures of TiCr2 in Ti-Cr alloys

    International Nuclear Information System (INIS)

    Chen, K.C.; Allen, S.M.; Livingston, J.D.

    1992-01-01

    The morphologies and defect structures of TiCr 2 in several Ti-Cr alloys have been examined by optical metallography, x-ray diffraction, and transmission electron microscopy (TEM), in order to explore the room-temperature deformability of the Laves phase TiCr 2 . The morphology of the Laves phase was found to be dependent upon alloy composition and annealing temperature. Samples deformed by compression have also been studied using TEM. Comparisons of microstructures before and after deformation suggest an increase in twin, stacking fault, and dislocation density within the Laves phase, indicating some but not extensive room-temperature deformability

  17. Structure of Ni-rich Ni--Cr--B--Si coating alloys

    International Nuclear Information System (INIS)

    Knotek, O.; Lugscheider, E.; Reimann, H.

    1975-01-01

    The structures of quaternary, nickel-rich Ni--Cr--B--Si alloys were analyzed at a constant boron content of 10 at. percent and a temperature of 850 0 C. The composition range for silicide formation was determined. In these quaternary alloys, known binary nickel silicides, nickel and chromium borides, and the ternary silico-boride Ni 6 Si 2 B were confirmed. A new composition for the W 5 Si 3 -type phase in the Ni--B--Si system was proposed. (U.S.)

  18. Chemical, electronic, and magnetic structure of LaFeCoSi alloy: Surface and bulk properties

    Energy Technology Data Exchange (ETDEWEB)

    Lollobrigida, V. [Dipartimento di Scienze, Università Roma Tre, I-00146 Rome (Italy); Dipartimento di Matematica e Fisica, Università Roma Tre, I-00146 Rome (Italy); Basso, V.; Kuepferling, M.; Coïsson, M.; Olivetti, E. S.; Celegato, F. [Istituto Nazionale di Ricerca Metrologica (INRIM), I-10135 Torino (Italy); Borgatti, F. [CNR, Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), I-40129 Bologna (Italy); Torelli, P.; Panaccione, G. [CNR, Istituto Officina dei Materiali (IOM), Lab. TASC, I-34149 Trieste (Italy); Tortora, L. [Laboratorio di Analisi di Superficie, Dipartimento di Matematica e Fisica, Università Roma Tre, I-00146 Rome (Italy); Dipartimento di Ingegneria Meccanica, Università Tor Vergata, I-00133 Rome (Italy); Stefani, G.; Offi, F. [Dipartimento di Scienze, Università Roma Tre, I-00146 Rome (Italy)

    2014-05-28

    We investigate the chemical, electronic, and magnetic structure of the magnetocaloric LaFeCoSi compound with bulk and surface sensitive techniques. We put in evidence that the surface retains a soft ferromagnetic behavior at temperatures higher than the Curie temperature of the bulk due to the presence of Fe clusters at the surface only. This peculiar magnetic surface effect is attributed to the exchange interaction between the ferromagnetic Fe clusters located at the surface and the bulk magnetocaloric alloy, and it is used here to monitor the magnetic properties of the alloy itself.

  19. Chemical, electronic, and magnetic structure of LaFeCoSi alloy: Surface and bulk properties

    Science.gov (United States)

    Lollobrigida, V.; Basso, V.; Borgatti, F.; Torelli, P.; Kuepferling, M.; Coïsson, M.; Olivetti, E. S.; Celegato, F.; Tortora, L.; Stefani, G.; Panaccione, G.; Offi, F.

    2014-05-01

    We investigate the chemical, electronic, and magnetic structure of the magnetocaloric LaFeCoSi compound with bulk and surface sensitive techniques. We put in evidence that the surface retains a soft ferromagnetic behavior at temperatures higher than the Curie temperature of the bulk due to the presence of Fe clusters at the surface only. This peculiar magnetic surface effect is attributed to the exchange interaction between the ferromagnetic Fe clusters located at the surface and the bulk magnetocaloric alloy, and it is used here to monitor the magnetic properties of the alloy itself.

  20. Chemical, electronic, and magnetic structure of LaFeCoSi alloy: Surface and bulk properties

    International Nuclear Information System (INIS)

    Lollobrigida, V.; Basso, V.; Kuepferling, M.; Coïsson, M.; Olivetti, E. S.; Celegato, F.; Borgatti, F.; Torelli, P.; Panaccione, G.; Tortora, L.; Stefani, G.; Offi, F.

    2014-01-01

    We investigate the chemical, electronic, and magnetic structure of the magnetocaloric LaFeCoSi compound with bulk and surface sensitive techniques. We put in evidence that the surface retains a soft ferromagnetic behavior at temperatures higher than the Curie temperature of the bulk due to the presence of Fe clusters at the surface only. This peculiar magnetic surface effect is attributed to the exchange interaction between the ferromagnetic Fe clusters located at the surface and the bulk magnetocaloric alloy, and it is used here to monitor the magnetic properties of the alloy itself.

  1. Synthesis and structural characterization of amorphous alloys of the Fe-Ni-B type

    International Nuclear Information System (INIS)

    Cabral P, A.; Jimenez B, J.; Garcia S, I.

    2004-01-01

    It was prepared the alloy FeNiB for chemical reduction, using four p H values (5, 6, 7 and 7.5). To p H=6 partially oxidized particles were obtained, between 16 and 20%. In the synthesis to other p H values, the obtained particles were highly oxidized (65-90%) according to the X-ray diffraction results, in all the preparations the particles were partially crystallized, with crystal size that varied between 4 and 10 nm. The structure of these particles can be consider that they are formed by a nucleus due to the alloy and an oxide armor recovering it. (Author)

  2. Process-Structure-Property Relationship in Magnesium-Based Biodegradable Alloy for Biomedical Applications

    Science.gov (United States)

    Trivedi, Pramanshu

    Magnesium alloys are considered to be the next generation of biomaterials because of their ability to degrade in the physiological environment. We elucidate here the impact of multiaxial forging of Mg-2Zn-2Gd alloy on grain refinement to sub-micron regime and relate the structure to mechanical properties and biological functionality. As-cast and annealed samples were multiaxial forged (MAF) for a total number of two passes with a true strain of 2/pass. Considering that the microstructure governs the biological response of materials, we studied the constituents of the microstructure in conjunction with the mechanical behavior. The antimicrobial behavior in a Mg-2Zn-2Gd alloy with different grain size in the range of 44 microm to 710 nm was studied by seeding. Surface energy and contact angle measurements using goniometer and wettability were assessed with water, SBF, n-Hexane, and DMEM. The structure-property relationship in Mg-2Zn-2Gd alloy to maintaining mechanical integrity during degradation was studied by seeding Escherichia coli ( E. coli). Furthermore, we studied the effect of degradation behavior in the presence and absence of cells. This was followed by the study of bioactivity in terms of phases present on the surface and degradation products in simulated body fluid (SBF). Magnesium coated with apatite using a biomimetic approach were placed in a 24-well culture plate with alpha-MEM media and the degradation behavior was studied in the absence and presence of cells (seeding density: 10,000 cells/cm2). The change in pH was monitored at regular intervals. Cell attachment was studied by seeding the cells for 4h and cell viability was studied by seeding the cells for up to 1, 3, and 7 days. The study underscores that the fine-grained alloys exhibited superior mechanical properties, antimicrobial resistance, and cell attachment. The degradation rate was also least for fine-grained alloy. The higher surface energy of ultrafine-grained Mg-2Zn-2Gd alloy led to the

  3. Vacuum hot-pressed beryllium and TiC dispersion strengthened tungsten alloy developments for ITER and future fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiang, E-mail: xliu@swip.ac.cn [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, Sichuan (China); Chen, Jiming; Lian, Youyun; Wu, Jihong; Xu, Zengyu; Zhang, Nianman; Wang, Quanming; Duan, Xuro [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, Sichuan (China); Wang, Zhanhong; Zhong, Jinming [Northwest Rare Metal Material Research Institute, CNMC, Ningxia Orient Group Co. Ltd.,No.119 Yejin Road, Shizuishan City, Ningxia,753000 (China)

    2013-11-15

    Beryllium and tungsten have been selected as the plasma facing materials of the ITER first wall (FW) and divertor chamber, respectively. China, as a participant in ITER, will share the manufacturing tasks of ITER first-wall mockups with the European Union and Russia. Therefore ITER-grade beryllium has been developed in China and a kind of vacuum hot-pressed (VHP) beryllium, CN-G01, was characterized for both physical, and thermo-mechanical properties and high heat flux performance, which indicated an equivalent performance to U.S. grade S-65C beryllium, a reference grade beryllium of ITER. Consequently CN-G01 beryllium has been accepted as the armor material of ITER-FW blankets. In addition, a modification of tungsten by TiC dispersion strengthening was investigated and a W–TiC alloy with TiC content of 0.1 wt.% has been developed. Both surface hardness and recrystallization measurements indicate its re-crystallization temperature approximately at 1773 K. Deuterium retention and thermal desorption behaviors of pure tungsten and the TiC alloy were also measured by deuterium ion irradiation of 1.7 keV energy to the fluence of 0.5–5 × 10{sup 18} D/cm{sup 2}; a main desorption peak at around 573 K was found and no significant difference was observed between pure tungsten and the tungsten alloy. Further characterization of the tungsten alloy is in progress.

  4. Study of incomplete fusion sensitivity to projectile structure from forward recoil range distribution measurement

    International Nuclear Information System (INIS)

    Kumar, Harish; Tali, Suhail A.; Afzal Ansari, M.

    2017-01-01

    Recently, the projectile structure is found to affect the incomplete fusion (ICF) process by using α- and non-α-cluster structured projectiles which is explored in terms of projectile α-Q-value and is still limited only for a very few systems. Keeping in view the recent aspects especially the projectile structure effect on ICF, the present work is carried out in the series of experiment by using α- and non-α-cluster structured projectiles. Presently, the FRRDs of evaporation residues (ERs) produced in 13 C + 175 Lu system have been measured at ≈ 88 MeV energy. In this work, an attempt has been made to have a better knowledge of projectile α-Q-value effect on ICF

  5. Structural order and magnetism of rare-earth metallic amorphous alloys

    International Nuclear Information System (INIS)

    Maurer, M.

    1984-01-01

    Local symmetry (as evaluated from the electric field gradient tensor) and radial distribution functions (obtained by EXAFS measurement) are determined in a series of amorphous rare-earth base alloys. Local order is found to increase with the extent of heteroatomic interactions. Various magnetic phases (including ferromagnetic, spin-glass, reentrant spin-glass) occur for europium alloys with simple metals (Mg, Zn, Cd, Al, Au, ...). This variety reflects the sensitivity of exchange interactions to the presence of non-s conduction electrons. Asperomagnetic structures are established for the Dy alloys. The crystalline electric field interactions at the Dy 3+ ions are interpreted with the help of local symmetry data. Quadratic axial and non-axial crystal field terms are sufficient and necessary in order to account for the hyperfine and bulk experimental results [fr

  6. Structural and electronic properties of Si1−xGex alloy nanowires

    International Nuclear Information System (INIS)

    Iori, Federico; Ossicini, Stefano; Rurali, Riccardo

    2014-01-01

    We present first-principles density-functional calculations of Si 1−x Ge x alloy nanowires. We show that given the composition of the alloy, the structural properties of the nanowires can be predicted with great accuracy by means of Vegard's law, linearly interpolating the values of a pure Si and a pure Ge nanowire of the same diameter. The same holds, to some extent, also for electronic properties such as the band-gap. We also assess to what extend the band-gap varies as a function of disorder, i.e., how it changes for different random realization of a given concentration. These results make possible to tailor the desired properties of SiGe alloy nanowires starting directly from the data relative to the pristine wires.

  7. Effects of alloying on Co--Si eutectoid structures and properties

    International Nuclear Information System (INIS)

    Livingston, J.D.

    1976-01-01

    The effects of various ternary alloying elements on the microstructure and properties of directionally solidified and transformed Co-Si eutectoid alloys were studied. Aligned eutectoid structures were maintained with additions of up to 10 at. percent Ni. However, higher Ni additions led to changes in both the silicide and solid-solution phases, related changes in microstructure, and decreased tensile strength. Additions of 5 at. percent Cr, Cu, Fe, or Mn produced cellular eutectoid microstructures which deteriorated the mechanical properties. Additions of W, Ta, or Al led to eutectic, rather than eutectoid, microstructures. Alloys based on the Co-W-Si eutectic appear to have the most promising high-temperature mechanical properties

  8. Structure and Mechanical Properties of AlSiCuMg Alloy after Thermo Processing

    Directory of Open Access Journals (Sweden)

    Piątkowski J.

    2015-03-01

    Full Text Available In the dissertation it has been shown, that so called „time-thermal treatment” (TTT of the alloy in liquid state, as overheating the metal with around 250°C above the Tliq. and detaining it in this temperature for around 30 minutes, improves the mechanical properties (HB, Rm, R0,2. It was ascertained, that overheating the AlSi17Cu5Mg alloy aids the modification, resulting with microcrystalline structure. Uniform arrangement of the Si primeval crystals in the warp, and α(Al solution type, supersaturated with alloying elements present in the base content (Cu, Mg assures not only increased durability in the ambient temperature, but also at elevated temperature (250°C, what is an advantage, especially due to the use in car industry.

  9. Structural properties of calcogenic thin films and alloys subjected to synchrotron light

    International Nuclear Information System (INIS)

    Moura, P.R.; Almeida, D.P.; Lima, J.C. de; Campos, C.E.M.; Ponciano, C.R.

    2009-01-01

    Results on structural characterization of Sb 50 Te 50 and Te 24 In 38 Sb 38 alloys prepared as powder and after deposited as a thin films are presented. For that x ray diffraction and energy dispersive X-ray fluorescence were used. The nanocrystalline phases Sb 2 Te 2 and Sb 24 Te 9 were nucleated in both Sb 50 Te 50 and Te 24 In 38 Sb 38 alloys, respectively. The thin films of both binary and ternary alloys are mainly amorphous. According to X-ray fluorescence results the chemical composition inside the ultraviolet irradiated region on one of the binary thin film become different than that outside irradiation marks, suggesting Sb migration. (author)

  10. Study of the structure and development of the set of reference materials of composition and structure of heat resisting nickel and intermetallic alloys

    Directory of Open Access Journals (Sweden)

    E. B. Chabina

    2016-01-01

    Full Text Available Relevance of research: There are two sizes (several microns and nanodimensional of strengthening j'-phase in single-crystal heat resisting nickel and intermetallic alloys, used for making blades of modern gas turbine engines (GTD. For in-depth study of structural and phase condition of such alloys not only qualitative description of created structure is necessary, but quantitative analysis of alloy components geometrical characteristics. Purpose of the work: Development of reference material sets of heat resisting nickel and intermetallic alloy composition and structure. Research methods: To address the measurement problem of control of structural and geometrical characteristics of single-crystal heat resisting and intermetallic alloys by analytical microscopy and X-ray diffraction analysis the research was carried out using certified measurement techniques on facilities, entered in the Register of Measurement Means of the Russian Federation. The research was carried out on microsections, foils and plates, cut in the plane {100}. Results: It is established that key parameters, defining the properties of these alloys are particle size of strengthening j' -phase, the layer thickness of j-phase between them and parameters of phases lattice. Metrological requirements for reference materials of composition and structure of heat resisting nickel and intermetallic alloys are formulated. The necessary and sufficient reference material set providing the possibility to determine the composition and structure parameters of single-crystal heat resisting nickel and intermetallic alloys is defined. The developed RM sets are certified as in-plant reference materials. Conclusion: The reference materials can be used for graduation of spectral equipment when conducting element analysis of specified class alloys; for calibration of means of measuring alloy structure parameters; for measurement of alloys phases lattice parameters; for structure reference pictures

  11. Aging Optimization of Aluminum-Lithium Alloy L277 for Application to Cryotank Structures

    Science.gov (United States)

    Sova, B. J.; Sankaran, K. K.; Babel, H.; Farahmand, B.; Cho, A.

    2003-01-01

    Compared with aluminum alloys such as 2219, which is widely used in space vehicle for cryogenic tanks and unpressurized structures, aluminum-lithium alloys possess attractive combinations of lower density and higher modulus along with comparable mechanical properties and improved damage tolerance. These characteristics have resulted in the successful use of the aluminum-lithium alloy 2195 for the Space Shuttle External Tank, and the consideration of newer U.S. aluminum-lithium alloys such as L277 and C458 for future space vehicles. A design of experiments aging study was conducted for plate and a limited study on extrusions. To achieve the T8 temper, Alloy L277 is typically aged at 290 F for 40 hours. In the study for plate, a two-step aging treatment was developed through a design of experiments study and the one step aging used as a control. Based on the earlier NASA studies on 2195, the first step aging temperature was varied between 220 F and 260 F. The second step aging temperatures was varied between 290 F and 310 F, which is in the range of the single-step aging temperature. For extrusions, two, single-step, and one two-step aging condition were evaluated. The results of the design of experiments used for the T8 temper as well as a smaller set of experiments for the T6 temper for plate and the results for extrusions will be presented.

  12. Effects of Surface Structure and Chemical Composition of Binary Ti Alloys on Cell Differentiation

    Directory of Open Access Journals (Sweden)

    Ok-Sung Han

    2016-07-01

    Full Text Available Binary Ti alloys containing Fe, Mo, V and Zr were micro-arc oxidized and hydrothermally treated to obtain micro- and nano-porous layers. This study aimed to investigate cell differentiation on micro and micro/nanoporous oxide layers of Ti alloys. The properties of the porous layer formed on Ti alloys were characterized by X-ray diffraction pattern, microstructural and elemental analyses and inductively coupled plasma mass spectrometry (ICP-MS method. The MTT assay, total protein production and alkaline phosphatase (ALPase activity were evaluated using human osteoblast-like cells (MG-63. Microporous structures of micro-arc oxidized Ti alloys were changed to micro/nanoporous surfaces after hydrothermal treatment. Micro/nanoporous surfaces consisted of acicular TiO2 nanoparticles and micron-sized hydroxyapatite particles. From ICP and MTT tests, the Mo and V ions released from porous oxide layers were positive for cell viability, while the released Fe ions were negative for cell viability. Although the micro/nanoporous surfaces led to a lower total protein content than the polished and microporous Ti surfaces after cell incubation for 7 days, they caused higher ALPase activities after 7 days and 14 days of incubation except for V-containing microporous surfaces. The micro/nanoporous surfaces of Ti alloys were more efficient in inducing MG-63 cell differentiation.

  13. Fe–Al–Mn–C lightweight structural alloys: a review on the microstructures and mechanical properties

    Directory of Open Access Journals (Sweden)

    Hansoo Kim, Dong-Woo Suh and Nack J Kim

    2013-01-01

    Full Text Available Adding a large amount of light elements such as aluminum to steels is not a new concept recalling that several Fe–Al–Mn–C alloys were patented in 1950s for replacement of nickel or chromium in corrosion resistance steels. However, the so-called lightweight steels or low-density steels were revisited recently, which is driven by demands from the industry where steel has served as a major structural material. Strengthening without loss of ductility has been a triumph in steel research, but lowering the density of steel by mixing with light elements will be another prospect that may support the competitiveness against emerging alternatives such as magnesium alloys. In this paper, we review recent studies on lightweight steels, emphasizing the concept of alloy design for microstructures and mechanical properties. The influence of alloying elements on the phase constituents, mechanical properties and the change of density is critically reviewed. Deformation mechanisms of various lightweight steels are discussed as well. This paper provides a reason why the success of lightweight steels is strongly dependent on scientific achievements even though alloy development is closely related to industrial applications. Finally, we summarize some of the main directions for future investigations necessary for vitalizing this field of interest.

  14. Fe–Al–Mn–C lightweight structural alloys: a review on the microstructures and mechanical properties

    Science.gov (United States)

    Kim, Hansoo; Suh, Dong-Woo; Kim, Nack J

    2013-01-01

    Adding a large amount of light elements such as aluminum to steels is not a new concept recalling that several Fe–Al–Mn–C alloys were patented in 1950s for replacement of nickel or chromium in corrosion resistance steels. However, the so-called lightweight steels or low-density steels were revisited recently, which is driven by demands from the industry where steel has served as a major structural material. Strengthening without loss of ductility has been a triumph in steel research, but lowering the density of steel by mixing with light elements will be another prospect that may support the competitiveness against emerging alternatives such as magnesium alloys. In this paper, we review recent studies on lightweight steels, emphasizing the concept of alloy design for microstructures and mechanical properties. The influence of alloying elements on the phase constituents, mechanical properties and the change of density is critically reviewed. Deformation mechanisms of various lightweight steels are discussed as well. This paper provides a reason why the success of lightweight steels is strongly dependent on scientific achievements even though alloy development is closely related to industrial applications. Finally, we summarize some of the main directions for future investigations necessary for vitalizing this field of interest. PMID:27877553

  15. Fe-Al-Mn-C lightweight structural alloys: a review on the microstructures and mechanical properties.

    Science.gov (United States)

    Kim, Hansoo; Suh, Dong-Woo; Kim, Nack J

    2013-02-01

    Adding a large amount of light elements such as aluminum to steels is not a new concept recalling that several Fe-Al-Mn-C alloys were patented in 1950s for replacement of nickel or chromium in corrosion resistance steels. However, the so-called lightweight steels or low-density steels were revisited recently, which is driven by demands from the industry where steel has served as a major structural material. Strengthening without loss of ductility has been a triumph in steel research, but lowering the density of steel by mixing with light elements will be another prospect that may support the competitiveness against emerging alternatives such as magnesium alloys. In this paper, we review recent studies on lightweight steels, emphasizing the concept of alloy design for microstructures and mechanical properties. The influence of alloying elements on the phase constituents, mechanical properties and the change of density is critically reviewed. Deformation mechanisms of various lightweight steels are discussed as well. This paper provides a reason why the success of lightweight steels is strongly dependent on scientific achievements even though alloy development is closely related to industrial applications. Finally, we summarize some of the main directions for future investigations necessary for vitalizing this field of interest.

  16. Identification of a human protein-derived HIV-1 fusion inhibitor targeting the gp41 fusion core structure.

    Directory of Open Access Journals (Sweden)

    Lijun Chao

    Full Text Available The HIV-1 envelope glycoprotein (Env gp41 plays a crucial role in the viral fusion process. The peptides derived from the C-terminal heptad repeat (CHR of gp41 are potent HIV fusion inhibitors. However, the activity of these anti-HIV-1 peptides in vivo may be attenuated by their induction of anti-gp41 antibodies. Thus, it is essential to identify antiviral peptides or proteins with low, or no, immunogenicity to humans. Here, we found that the C-terminal fragment (aa 462-521 of the human POB1 (the partner of RalBP1, designated C60, is an HIV-1 fusion inhibitor. It bound to N36, the peptide derived from the N-terminal heptad repeat (NHR of gp41, and to the six-helix bundle (6-HB formed by N36 and C34, a CHR-peptide, but it did not bind to C34. Unlike the CHR-peptides, C60 did not block gp41 6-HB formation. Rather, results suggest that C60 inhibits HIV-1 fusion by binding to the 6-HB, in particular, the residues in the gp41 NHR domain that are exposed on the surface of 6-HB. Since 6-HB plays a crucial role in the late stage of fusion between the viral envelope and endosomal membrane during the endocytic process of HIV-1, C60 may serve as a host restriction factor to suppress HIV-1 entry into CD4+ T lymphocytes. Taken together, it can be concluded from these results that C60 can be used as a lead for the development of anti-HIV-1 therapeutics or microbicides for the treatment and prevention of HIV-1 infection, as well as a molecular probe to study the fusogenic mechanism of HIV-1.

  17. Optimisation by plastic deformation of structural and mechanical uranium alloys properties

    International Nuclear Information System (INIS)

    Prunier, Claude.

    1981-08-01

    Structural and mechanical properties evolution of rich and poor uranium alloys are investigated. Good usual properties are obtained with few metallic additions with a limited effect giving a fine and isotrope grain structure. Amelioration is observed with heat treatment from β and γ phases high temperature range. However, dynamic recrystallisation, related to hot working, is the better phenomena to maximize the usual mechanical and structural properties. So high temperature behaviour of rich and poor uranium alloys in α, β and γ crystalline structure is studied: - dynamic recrystallisation phenomena begins only in α, and β phases high temperature range; - high strength and brittle β phase shows a very large ductility above 700 deg C. Recrystallisation is a thermal actived phenomena localised at grain boundary, dependant with alloys concentration and crystalline structure. β phase activation energy and deformation rate for dynamic recrystallisation beginning are most important, than α and γ phases in relation with quadratic structure complexity. Both temperature and deformation rate are the main dynamic recrystallisation factors. Optimal usual mechanical and structural properties obtained by hot working (forging, milling) are sensible to hydrogen embrittlement [fr

  18. Structural conditions of achieving maximum ductility of two-phase Ni-NiO alloys

    International Nuclear Information System (INIS)

    Grabin, V.V.; Dabizha, E.V.; Movchan, B.A.

    1984-01-01

    A study was made on possibility of increasing ductility of two-phase Ni-NiO alloys, proJuced by traditional technology: ingot smelting, rolling and corresponding annealing for production of grain with certain size. The correlation of mechanical properties of Ni-NiO alloys and pure nickel shows that completion of the structural conJition D--lambda (where D - the average grain diameter, lambda - the value of free path between particles) in two-phase alloys enables: to increase the ultimate strength 1.5 times and preserve the basic level of pure nickel plasticity - at 20 deg C; to increase plasticity 1.4-1.5 times with preserved basic level of pure nickel plasticity - at 800 deg C. The conclusions testify to possibility of controlling mechanical properties of two-phase alloys using structural D and lambda parameters It is proposed that creation of structures with more unifor m particle distribution with respect to sizes will the accompanied by further increase of plasticity under D=lambda condition

  19. Formation and structure of V-Zr amorphous alloy thin films

    KAUST Repository

    King, Daniel J M

    2015-01-01

    Although the equilibrium phase diagram predicts that alloys in the central part of the V-Zr system should consist of V2Zr Laves phase with partial segregation of one element, it is known that under non-equilibrium conditions these materials can form amorphous structures. Here we examine the structures and stabilities of thin film V-Zr alloys deposited at room temperature by magnetron sputtering. The films were characterized by X-ray diffraction, transmission electron microscopy and computational methods. Atomic-scale modelling was used to investigate the enthalpies of formation of the various competing structures. The calculations confirmed that an amorphous solid solution would be significantly more stable than a random body-centred solid solution of the elements, in agreement with the experimental results. In addition, the modelling effort provided insight into the probable atomic configurations of the amorphous structures allowing predictions of the average distance to the first and second nearest neighbours in the system.

  20. Effect of tantalum on α-martensite crystal structure in Co-Ta alloy

    International Nuclear Information System (INIS)

    Skorodzievskij, V.S.; Ustinov, A.I.; Chuistov, K.V.

    1985-01-01

    Changes in the crystal structure of α-martensite, formed during Co-Ta alloy hardening from the region of a homogeneous solid solution, are investigated by X-ray analysis methods. In case of increasing tantalum content in the alloy, intensity redistribution of X-ray scattering along the direction of the reverse space of H-K not equal to 3N (N=0, +-1, +-2...) type is fixed, which appears, depending on concentration, in continuous displacement of maxima from positions being characteristic for the initial 2H structure, as well as in occurring additional maxima and in changing the ratio between them by ipteΣity. For limiting values of tantalum concentration, where β → α-transformations are still observed, the number of intepsity maxima and their positions an the period of α-martensite reverse lattice recurrence period is closer to the location of 15R 1 -structure reverse structure unit

  1. Influence of structural relaxation and partial devitrification on the corrosion resistance of Fe78B13Si9 amorphous alloy

    International Nuclear Information System (INIS)

    Souza, C.A.C.; Politi, F.S.; Kiminami, C.S.

    1998-01-01

    Amorphous alloys obtained by rapid solidification from the melt exhibit a similar structure to those observed in the liquid state, i.e., without long range ordering, in such a way that the constituents of the alloy usually are randomly and homogeneously distributed. Amorphous alloys, depending on their composition, may exhibit interesting characteristics such as very soft magnetic properties and improved resistance to corrosion. The high corrosion resistance of these alloys is attributed mainly to a higher rate of dissolution of passivating elements in the amorphous state. In addition, amorphous alloys are chemically homogeneous and free of defects such as grain boundaries, precipitates and segregation, which are favorable sites for corrosion. The corrosion resistance of amorphous alloys also depends on their thermal history. Several authors have reported that structural changes, such as structural relaxation and devitrification caused by annealing, change significantly the corrosion properties of these alloys. The purpose of this paper is to study corrosion resistance of the amorphous FeBSi alloy and the effects of structural changes such as structural relaxation and partial crystallization caused by annealing

  2. RCC-MRx: Design and construction rules for mechanical components in high-temperature structures, experimental reactors and fusion reactors

    International Nuclear Information System (INIS)

    2015-01-01

    The RCC-MRx code was developed for sodium-cooled fast reactors (SFR), research reactors (RR) and fusion reactors (FR-ITER). It provides the rules for designing and building mechanical components involved in areas subject to significant creep and/or significant irradiation. In particular, it incorporates an extensive range of materials (aluminum and zirconium alloys in response to the need for transparency to neutrons), sizing rules for thin shells and box structures, and new modern welding processes: electron beam, laser beam, diffusion and brazing. The RCC-MR code was used to design and build the prototype Fast Breeder Reactor (PFBR) developed by IGCAR in India and the ITER Vacuum Vessel. The RCC-Mx code is being used in the current construction of the RJH experimental reactor (Jules Horowitz reactor). The RCC-MRx code is serving as a reference for the design of the ASTRID project (Advanced Sodium Technological Reactor for Industrial Demonstration), for the design of the primary circuit in MYRRHA (Multi-purpose hybrid Research Reactor for High-tech Applications) and the design of the target station of the ESS project (European Spallation Source). Contents of the 2015 edition of the RCC-MRx code: Section I General provisions; Section II Additional requirements and special provisions; Section III Rules for nuclear installation mechanical components: Volume I: Design and construction rules: Volume A (RA): General provisions and entrance keys, Volume B (RB): Class 1 components and supports, Volume C (RC): Class 2 components and supports, Volume D (RD): Class 3 components and supports, Volume K (RK): Examination, handling or drive mechanisms, Volume L (RL): Irradiation devices, Volume Z (Ai): Technical appendices; Volume II: Materials; Volume III: Examinations methods; Volume IV: Welding; Volume V: Manufacturing operations; Volume VI: Probationary phase rules

  3. Reactive wetting of amorphous silica by molten Al–Mg alloys and their interfacial structures

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Laixin [Key Laboratory of Automobile Materials (Ministry of Education), Department of Materials Science and Engineering, Jilin University, No. 5988 Renmin Street, Changchun 130025 (China); School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Shen, Ping, E-mail: shenping@jlu.edu.cn [Key Laboratory of Automobile Materials (Ministry of Education), Department of Materials Science and Engineering, Jilin University, No. 5988 Renmin Street, Changchun 130025 (China); Zhang, Dan [Editorial Office, Journal of Bionic Engineering, Jilin University, No. 5988 Renmin Street, Changchun 130025 (China); Jiang, Qichuan [Key Laboratory of Automobile Materials (Ministry of Education), Department of Materials Science and Engineering, Jilin University, No. 5988 Renmin Street, Changchun 130025 (China)

    2016-07-30

    Highlights: • The wettability improves with increasing Mg concentration and temperature. • Reaction product zone consists of layered structures relating with Mg concentration. • Formation of MgAl{sub 2}O{sub 4} and MgO at the interface does not promote the wettability. • Formation of Mg{sub 2}Si plays a dominant role in promoting the wettability. • Anomalous recession of the triple line was mainly due to diminishing Mg in the alloy. - Abstract: The reactive wetting of amorphous silica substrates by molten Al–Mg alloys over a wide composition range was studied using a dispensed sessile drop method in a flowing Ar atmosphere. The effects of the nominal Mg concentration and temperature on the wetting and interfacial microstructures were discussed. The initial contact angle for pure Al on the SiO{sub 2} surface was 115° while that for pure Mg was 35° at 1073 K. For the Al–Mg alloy drop, it decreased with increasing nominal Mg concentration. The reaction zone was characterized by layered structures, whose formation was primarily controlled by the variation in the alloy concentration due to the evaporation of Mg and the interfacial reaction from the viewpoint of thermodynamics as well as by the penetration or diffusion of Mg, Al and Si from the viewpoint of kinetics. In addition, the effects of the reaction and the evaporation of Mg on the movement of the triple line were examined. The spreading of the Al–Mg alloy on the SiO{sub 2} surface was mainly attributed to the formation of Mg{sub 2}Si at the interface and the recession of the triple line to the diminishing Mg concentration in the alloy.

  4. Structure of Ti-6Al-4V nanostructured titanium alloy joint obtained by resistance spot welding

    Energy Technology Data Exchange (ETDEWEB)

    Klimenov, V. A., E-mail: klimenov@tpu.ru [Tomsk State University of Architecture and Building, 2 Solyanaya Sq, Tomsk, 634003 (Russian Federation); National Research Tomsk Polytechnic University, 30 Lenin Av., Tomsk, 634050 (Russian Federation); Kurgan, K. A., E-mail: kirill-k2.777@mail.ru [Tomsk State University of Architecture and Building, 2 Solyanaya Sq, Tomsk, 634003 (Russian Federation); Chumaevskii, A. V., E-mail: tch7av@gmail.com [Institute of Strength Physics and Materials Science, Siberian Branch of the Russian Academy of Sciences, 2/4 Akademicheskii pr., Tomsk, 634021 (Russian Federation); Klopotov, A. A., E-mail: klopotovaa@tsuab.ru [Tomsk State University of Architecture and Building, 2 Solyanaya Sq, Tomsk, 634003 (Russian Federation); National Research Tomsk State University, 36 Lenin Ave., Tomsk, 634050 (Russian Federation); Gnyusov, S. F., E-mail: gnusov@rambler.ru [National Research Tomsk Polytechnic University, 30 Lenin Av., Tomsk, 634050 (Russian Federation)

    2016-01-15

    The structure of weld joints of the titanium alloy Ti-6Al-4V in the initial ultrafine-grained state, obtained by resistance spot welding, is studied using the optical and scanning electron microscopy method and the X-ray structure analysis. The carried out studies show the relationship of the metal structure in the weld zone with main joint zones. The structure in the core zone and the heat affected zone is represented by finely dispersed grains of needle-shaped martensite, differently oriented in these zones. The change in the microhardness in the longitudinal section of the weld joint clearly correlates with structural changes during welding.

  5. Recent developments in transient magneto-structural integrated analysis for fusion applications

    International Nuclear Information System (INIS)

    Crutzen, Y.; Papadopoulos, S.; Richard, N.; Siakavellas, N.; Wu, J.

    1992-01-01

    In this paper three different numerical approaches modelling the mutual field-structure interactions during transient electromagnetic events are presented. The application of these approaches to simple plate models, simulating flexible conducting components of fusion devices, show that a magnetic damping is encountered when coupling effects between eddy currents and plate motion are taken into account. This damping increases with the applied magnetic field, modifying the mechanical behavior. An Integrated Design/Analysis System is also proposed, in order to combine different computer codes, obtaining performing computational schemes, in the field of 3D electromagneto-mechanical analyses

  6. Conceptual design of nuclear fusion power reactor DREAM. Reactor structures and remote maintenance

    International Nuclear Information System (INIS)

    Nishio, Satoshi; Seki, Yasushi; Ueda, Shuzo; Kurihara, Ryoichi; Adachi, Junichi; Yamazaki, Seiichiro; Hashimoto, Toshiyuki.

    1997-01-01

    Nuclear fusion reactors are required to be able to compete another energy sources in economy, reliability, safety and environmental integrity for commercial use. In the DREAM (DRastically EAsy Maintenance) reactor, a very low activated material of SiC/SiC composite has been introduced for the structural material, a reactor configuration for very easy maintenance and the helium gas of a high temperature for the cooling system, and hence DREAM has been proven to be very attractively as the commercial power reactor due to the high availability and efficiency of the plant and minimization of radioactive wastes. (author)

  7. Contribution of Shape Memory Alloys Elements in Designing Underwater Smart Structures

    Directory of Open Access Journals (Sweden)

    Daniel Amariei

    2007-10-01

    Full Text Available Shape memory alloys (SMA have generated a lot of new ideas in engineering. Application is however so far limited to clamps and springs. With respect to smart structures sensing as well as control has to be included. While sensing looks to be relatively feasible control is the big challenge. This paper describes some related a smart structure idea using SMAs and discusses the challenges which need to be solved before these ideas can be realised.

  8. Structure and Stability of Pt-Y Alloy Particles for Oxygen Reduction Studied by Electron Microscopy

    DEFF Research Database (Denmark)

    Deiana, Davide; Wagner, Jakob Birkedal; Hansen, Thomas Willum

    2015-01-01

    Platinum-yttrium alloy nanoparticles show both a high activity and stability for the oxygen reduction reaction. The catalysts were prepared by magnetron sputter aggregation and mass filtration providing a model catalyst system with a narrow size distribution. The structure and stability of nanost...... the catalyst after reaction and after aging tests shows the development of a core-shell type structure after being exposed to reaction conditions....

  9. Structural studies of amorphous Mo-Ge alloys using synchrotron radiation

    International Nuclear Information System (INIS)

    Kortright, J.B.

    1984-06-01

    Structural changes in sputtered amorphous Mo-Ge alloy films with composition varying from a-Ge to about 70 at. % Mo have been studied with several x-ray techniques. Results of individual techniques are presented and discussed in separate chapters. The complementary nature of information obtained from EXAFS and scattering for these materials is discussed in a separate chapter. A concluding chapter summarizes the results and structural changes with composition

  10. Band structure of Mgsub(x)Znsub(1-x)Te alloys

    International Nuclear Information System (INIS)

    Laugier, A.; Montegu, B.; Barbier, D.; Chevallier, J.; Guillaume, J.C.; Somogyi, K.

    1980-01-01

    The band structure of Mgsub(x)Znsub(1-x)Te alloys is studied using a double beam wavelength modulated system in first derivative mode. Modulated reflectivity measurements are made from 82 to 300 K within spectral range 2500 to 5400 A. Structures corresponding to the E 0 , E 0 + Δ 0 , E 1 , E 1 + Δ 1 , e 1 and e 1 + Δ 1 critical points are indexed on the basis of existing band calculations for ZnTe. (author)

  11. Automatic structural parcellation of mouse brain MRI using multi-atlas label fusion.

    Directory of Open Access Journals (Sweden)

    Da Ma

    Full Text Available Multi-atlas segmentation propagation has evolved quickly in recent years, becoming a state-of-the-art methodology for automatic parcellation of structural images. However, few studies have applied these methods to preclinical research. In this study, we present a fully automatic framework for mouse brain MRI structural parcellation using multi-atlas segmentation propagation. The framework adopts the similarity and truth estimation for propagated segmentations (STEPS algorithm, which utilises a locally normalised cross correlation similarity metric for atlas selection and an extended simultaneous truth and performance level estimation (STAPLE framework for multi-label fusion. The segmentation accuracy of the multi-atlas framework was evaluated using publicly available mouse brain atlas databases with pre-segmented manually labelled anatomical structures as the gold standard, and optimised parameters were obtained for the STEPS algorithm in the label fusion to achieve the best segmentation accuracy. We showed that our multi-atlas framework resulted in significantly higher segmentation accuracy compared to single-atlas based segmentation, as well as to the original STAPLE framework.

  12. The structure-property relationships of powder processed Fe-Al-Si alloys

    Energy Technology Data Exchange (ETDEWEB)

    Prichard, Paul D. [Iowa State Univ., Ames, IA (United States)

    1998-02-23

    Iron-aluminum alloys have been extensively evaluated as semi-continuous product such as sheet and bar, but have not been evaluated by net shape P/M processing techniques such as metal injection molding. The alloy compositions of iron-aluminum alloys have been optimized for room temperature ductility, but have limited high temperature strength. Hot extruded powder alloys in the Fe-Al-Si system have developed impressive mechanical properties, but the effects of sintering on mechanical properties have not been explored. This investigation evaluated three powder processed Fe-Al-Si alloys: Fe-15Al, Fe-15Al-2.8Si, Fe-15Al-5Si (atomic %). The powder alloys were produced with a high pressure gas atomization (HPGA) process to obtain a high fraction of metal injection molding (MIM) quality powder (D84 < 32 μm). The powders were consolidated either by P/M hot extrusion or by vacuum sintering. The extruded materials were near full density with grain sizes ranging from 30 to 50 μm. The vacuum sintering conditions produced samples with density ranging from 87% to 99% of theoretical density, with an average grain size ranging from 26 μm to 104 μm. Mechanical property testing was conducted on both extruded and sintered material using a small punch test. Tensile tests were conducted on extruded bar for comparison with the punch test data. Punch tests were conducted from 25 to 550 C to determine the yield strength, and fracture energy for each alloy as a function of processing condition. The ductile to brittle transition temperature (DBTT) was observed to increase with an increasing silicon content. The Fe-15Al-2.8Si alloy was selected for more extensive testing due to the combination of high temperature strength and low temperature toughness due to the two phase α + DO3 structure. This investigation provided a framework for understanding the effects of silicon in powder processing and mechanical property behavior of Fe-Al-Si alloys.

  13. Special topics reports for the reference tandem mirror fusion breeder. Volume 4. Structural analysis

    International Nuclear Information System (INIS)

    Orient, G.; Westmann, R.A.; Ghoniem, N.M.; Garner, J.K.; Gromada, R.G.

    1984-12-01

    This report presents a structural analysis of the reference fission suppressed fusion breeder blanket. An axisymmetric structural model is used to analyze thermal and pressure stresses in the blanket. Results indicate that the first wall must be decoupled from the back of the blanket to avoid large thermal stresses. The composite first wall appears to be adequate to resist buckling, and is further strengthened by radial diaphragms. Semieliptical closures for the module ends appear to be feasible, although the attachment of these end closures to the composite first wall has not been analyzed. Radiation effects have not been included in the structural model, but an assessment of creep and swelling indicates a 4 to 5 year blanket life at an assumed strain limit of 2%. Design modifications which will reduce thermal stresses and simplify manufacturing are recommended

  14. Structure of Sn1−xGex random alloys as obtained from the coherent potential approximation

    KAUST Repository

    Pulikkotil, J. J.; Chroneos, A.; Schwingenschlö gl, Udo

    2011-01-01

    The structure of the Sn1−xGex random alloys is studied using density functional theory and the coherent potential approximation. We report on the deviation of the Sn1−xGex alloys from Vegard’s law, addressing their full compositional range

  15. Critical evaluation on structural stiffness of porous cellular structure of cobalt chromium alloy

    Science.gov (United States)

    Abd Malek, N. M. S.; Mohamed, S. R.; Che Ghani, S. A.; Harun, W. S. Wan

    2015-12-01

    In order to improve the stiffness characteristics of orthopedic devices implants that mimic the mechanical behavior of bone need to be considered. With the capability of Additive layer manufacturing processes to produce orthopedic implants with tailored mechanical properties are needed. This paper discusses finite element (FE) analysis and mechanical characterization of porous medical grade cobalt chromium (CoCr) alloy in cubical structures with volume based porosity ranging between 60% to 80% produced using direct metal laser sintering (DMLS) process. ANSYS 14.0 FE modelling software was used to predict the effective elastic modulus of the samples and comparisons were made with the experimental data. The effective mechanical properties of porous samples that were determined by uniaxial compression testing show exponential decreasing trend with the increase in porosity. Finite element model shows good agreement with experimentally obtained stress-strain curve in the elastic regions. The models prove that numerical analysis of actual prosthesis implant can be computed particularly in load bearing condition

  16. Critical evaluation on structural stiffness of porous cellular structure of cobalt chromium alloy

    International Nuclear Information System (INIS)

    Abd Malek, N M S; Mohamed, S R; Che Ghani, S A; Wan Harun, W S

    2015-01-01

    In order to improve the stiffness characteristics of orthopedic devices implants that mimic the mechanical behavior of bone need to be considered. With the capability of Additive layer manufacturing processes to produce orthopedic implants with tailored mechanical properties are needed. This paper discusses finite element (FE) analysis and mechanical characterization of porous medical grade cobalt chromium (CoCr) alloy in cubical structures with volume based porosity ranging between 60% to 80% produced using direct metal laser sintering (DMLS) process. ANSYS 14.0 FE modelling software was used to predict the effective elastic modulus of the samples and comparisons were made with the experimental data. The effective mechanical properties of porous samples that were determined by uniaxial compression testing show exponential decreasing trend with the increase in porosity. Finite element model shows good agreement with experimentally obtained stress-strain curve in the elastic regions. The models prove that numerical analysis of actual prosthesis implant can be computed particularly in load bearing condition (paper)

  17. Analysis of irradiation creep and the structural integrity of fusion in-vessel components

    International Nuclear Information System (INIS)

    Karditsas, Panayiotis J.

    2000-01-01

    This paper presents a brief review of the irradiation creep mechanism, analyses of the effect on the performance and behaviour of fusion in-vessel components, and discusses procedures for the estimation of in-service time (or lifetime) of components under combined creep-fatigue. The irradiation creep models and proposed theories are examined and analysed to produce a creep law relevant to fusion conditions. The necessary material data, constitutive equations and other parameters needed for estimation of in-service time from the combination of creep and fatigue damage are identified. Wherever possible, design curves are proposed for stress and strain. Time dependent non-linear elastoplastic example calculations are performed, for a typical first wall structure under power plant loading conditions, assuming austenitic and martensitic steel as structural materials, including material irradiation creep. The results of calculations for the stress and strain history of the first wall are used together with the proposed cumulative damage expressions derived in this study to estimate the in-service time, including the effects of stress relaxation due to creep, reduction of ductility (or fracture strain) and helium-to-displacement-damage ratio. The calculations give a displacement damage of ∼70 dpa for the 316 austenitic steel and ∼110-130 dpa for the martensitic steel. Provided there are no power transients, for a design strain of 0.5%, the in-service time is estimated to be ∼3 years for the 316 steel case (at 2.2 MW/m 2 wall load) and the high wall loading martensitic steel (5.0 MW/m 2 case), and ∼5.3 years for the martensitic steel at lower wall load (2.2 MW/m 2 case). The difficulty in defending these results lies in the uncertainty arising from the limited database and experience of the material properties, especially the creep constitutive law, when exposed to fusion environments

  18. Near term, low cost, 14 MeV fusion neutron irradiation facility for testing the viability of fusion structural materials

    Energy Technology Data Exchange (ETDEWEB)

    Kulcinski, Gerald L., E-mail: glkulcin@wisc.edu [University of Wisconsin-Madison, Madison, WI (United States); Radel, Ross F. [Phoenix Nuclear Labs LLC, Monona, WI (United States); Davis, Andrew [University of Wisconsin-Madison, Madison, WI (United States)

    2016-11-01

    For over 50 years, engineers have been looking for an irradiation facility that can provide a fusion reactor appropriate neutron spectrum over a significant volume to test fusion reactor materials that is relatively inexpensive and can be built in a minimum of time. The 14 MeV neutron irradiation facility described here can nearly exactly duplicate the neutron spectrum typical of a DT fusion reactor first wall at damage rates of ≈4 displacements per atom and 40 appm He generated over a 2 l volume per full power year of operation. The projected cost of this multi-beam facility is estimated at ≈$20 million and it can be built in <4 years. A single-beam prototype, funded by the U.S. Department of Energy, is already being built to produce medical isotopes. The neutrons are produced by a 300 keV deuterium beam accelerated into 4 kPa (30 Torr) tritium target. The total tritium inventory is <2 g and <0.1 g of T{sub 2} is consumed per year. The core technology proposed has already been fully demonstrated, and no new plasma physics or materials innovations will be required for the test facility to become operational.

  19. First-principles study of ternary bcc alloys using special quasi-random structures

    International Nuclear Information System (INIS)

    Jiang Chao

    2009-01-01

    Using a combination of exhaustive enumeration and Monte Carlo simulated annealing, we have developed special quasi-random structures (SQSs) for ternary body-centered cubic (bcc) alloys with compositions of A 1 B 1 C 1 , A 2 B 1 C 1 , A 6 B 1 C 1 and A 2 B 3 C 3 , respectively. The structures possess local pair and multisite correlation functions that closely mimic those of the random bcc alloy. We employed the SQSs to predict the mixing enthalpies, nearest neighbor bond length distributions and electronic density of states of bcc Mo-Nb-Ta and Mo-Nb-V solid solutions. Our convergence tests indicate that even small-sized SQSs can give reliable results. Based on the SQS energetics, the predicting powers of the existing empirical ternary extrapolation models were assessed. The present results suggest that it is important to take into account the ternary interaction parameter in order to accurately describe the thermodynamic behaviors of ternary alloys. The proposed SQSs are quite general and can be applied to other ternary bcc alloys.

  20. Ti2FeZ (Z=Al, Ga, Ge) alloys: Structural, electronic, and magnetic properties

    International Nuclear Information System (INIS)

    Liping, Mao; Yongfan, Shi; Yu, Han

    2014-01-01

    Using the first-principle projector augmented wave potential within the generalized gradient approximation taking into account the on-site Coulomb repulsive, we investigate the structural, electronic and magnetic properties of Ti 2 FeZ (Z=Al, Ga, Ge) alloys with Hg 2 CuTi-type structure. These alloys are found to be half-metallic ferrimagnets. The total magnetic moments of the Heusler alloys Ti 2 FeZ follow the µ t =Z t −18 rule and agree with the Slater–Pauling curve quite well. The band gaps are mainly determined by the bonding and antibonding states created from the hybridizations of the d states between the Ti(A)–Ti(B) coupling and Fe atom. - Highlights: • Ti 2 FeZ (Z=Al, Ga, Ge) are found to be half-metallic ferrimagnets. • The band gaps are mainly determined by the hybridizations of the d states between the Ti(A)–Ti(B) coupling and Fe atom. • The s–p elements play an important role in the half-metallicity of these Heusler alloys

  1. Formation, stability and crystal structure of the {sigma} phase in Mo-Re-Si alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bei, H., E-mail: beih@ornl.gov [Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge, TN 37831 (United States); Yang, Y., E-mail: ying.yang@computherm.com [CompuTherm LLC, Madison, WI 53719 (United States); Viswanathan, G.B. [Air Force Research Laboratory, Wright-Patterson AFB, OH 45433 (United States); Rawn, C.J.; George, E.P. [Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge, TN 37831 (United States)] [University of Tennessee, Department of Materials Science and Engineering, Knoxville, TN 37996 (United States); Tiley, J. [Air Force Research Laboratory, Wright-Patterson AFB, OH 45433 (United States); Chang, Y.A. [CompuTherm LLC, Madison, WI 53719 (United States)] [University of Wisconsin-Madison, Madison, WI 53705 (United States)

    2010-10-15

    The formation, stability and crystal structure of the {sigma} phase in Mo-Re-Si alloys were investigated. Guided by thermodynamic calculations, six critically selected alloys were arc melted and annealed at 1600 deg. C for 150 h. Their as-cast and annealed microstructures, including phase fractions and distributions, the compositions of the constituent phases and the crystal structure of the {sigma} phase were analyzed by thermodynamic modeling coupled with experimental characterization by scanning electron microscopy, electron probe microanalysis, X-ray diffraction and transmission electron microscopy. Two key findings resulted from this work. One is the large homogeneity range of the {sigma} phase region, extending from binary Mo-Re to ternary Mo-Re-Si. The other is the formation of a {sigma} phase in Mo-rich alloys either through the peritectic reaction of liquid + Mo{sub ss} {yields} {sigma} or primary solidification. These findings are important in understanding the effects of Re on the microstructure and providing guidance on the design of Mo-Re-Si alloys.

  2. Structural transformations in the Co53Mo35Cr12 alloy at different temperatures

    International Nuclear Information System (INIS)

    Ustinovshikov, Y.

    2014-01-01

    Highlights: • Phase separation microstructures are formed in the alloy studied below solidus line. • Co 3 Mo chemical compound precipitates in the liquidus–solidus temperature interval. • Ordering-phase separation transition takes place in Co/Mo diffusional couple only. - Abstract: Structural transformations of the Co 53 Mo 35 Cr 12 alloy were studied at temperatures of 1250, 1000 and 700 °C, when in all the three diffusion couples of the alloy there takes place a tendency to phase separation and at a temperature above the solidus, when in the Co/Mo diffusion couple there appears a tendency to ordering and the So 3 Mo phase is formed. It has been shown that at a temperature of 1250 °C, this phase is completely dissolved, and in the process of such dissolution, a Co-enriched fcc solid solution with a large number of stacking faults is formed. Simultaneously, there occurs precipitation of particles of Sr atoms, the sizes of which grow with lowering the temperature of heat treatment. The stacking faults, formed at 1250 °C, turn out to be the place, where laths enriched in Mo atoms, begin to form. After a heat treatment at 700 °C, the whole structure of the alloy consists of light-color and dark laths, arranged along the elastically- soft directions of the matrix. Each of these laths is enriched in atoms of either cobalt (fcc lattice) or molybdenum (bcc lattice)

  3. The structural and phase state formed in construction titanium alloy by radial forging

    Energy Technology Data Exchange (ETDEWEB)

    Shlyakhova, Galina V.; Danilov, Vladimir I.; Orlova, Dina V.; Zuev, Lev B. [Institute of Strength Physics and Materials Science SB RAS, Tomsk (Russian Federation); Zavodchikov, Aleksandr S. [Perm State Technical University, Perm (Russian Federation)

    2011-07-01

    The feasibility of rod manufacture from construction titanium alloy using radial forging on a high duty machine SXK16 was investigated. The investigations were carried on for titanium rod samples using the methods of metallography, electron transmission microscophy and X-ray analysis. The results obtained are described herein. It is found that radial forging results in the formation of homogeneous fine-grained structure.Using radial forging process, high-quality items are produced. As-worked material has submicrocrystalline globular structure and an optimal α:β phase ratio. Besides, the technology is more cost-effective relative to conventional flow charts. Key words: forging, titanium alloy, fine-grain structure, substructure, pore size.

  4. Transport, Structural and Mechanical Properties of Quaternary FeVTiAl Alloy

    Science.gov (United States)

    Bhat, Tahir Mohiuddin; Gupta, Dinesh C.

    2016-11-01

    The electronic, structural, magnetic and transport properties of FeVTiAl quaternary alloy have been investigated within the framework of density functional theory. The material is a completely spin-polarized half-metallic ferromagnet in its ground state with F-43m structure. The structural stability was further confirmed by elastic constants in the cubic phase with high Young's modulus and brittle nature. The present study predicts an energy band gap of 0.72 eV in a localized minority spin channel at equilibrium lattice parameter of 6.00 Å. The transport properties of the material are discussed based on the Seebeck coefficient, and electrical and thermal conductivity coefficients. The alloy presents large values of Seebeck coefficients, ~39 μV K-1 at room temperature (300 K), and has an excellent thermoelectric performance with ZT = ~0.8.

  5. Structural evolution of Ni-20Cr alloy during ball milling of elemental powders

    International Nuclear Information System (INIS)

    Lopez B, I.; Trapaga M, L. G.; Martinez F, E.; Zoz, H.

    2011-01-01

    The ball milling (B M) of blended Ni and Cr elemental powders was carried out in a Simoloyer performing on high-energy scale mode at maximum production to obtain a nano structured Ni-20Cr alloy. The phase transformations and structural changes occurring during mechanical alloying were investigated by X-ray diffraction (XRD) and optical microscopy (Om). A gradual solid solubility of Cr and the subsequent formation of crystalline metastable solid solutions described in terms of the Avrami-Ero fe ev kinetics model were calculated. The XRD analysis of the structure indicates that cumulative lattice strain contributes to the driving force for solid solution between Ni and Cr during B M. Microstructure evolution has shown, additionally to the lamellar length refinement commonly observed, the folding of lamellae in the final processing stage. Om observations revealed that the lamellar spacing of Ni rich zones reaches a steady value near 500 nm and almost disappears after 30 h of milling. (Author)

  6. Average Structure Evolution of δ-phase Pu-Ga Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Alice Iulia [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Page, Katharine L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Gourdon, Olivier [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Siewenie, Joan E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Richmond, Scott [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Saleh, Tarik A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ramos, Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Schwartz, Daniel S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-03-30

    [Full Text] Plutonium metal is a highly unusual element, exhibiting six allotropes at ambient pressure, from room temperature to its melting point. Many phases of plutonium metal are unstable with temperature, pressure, chemical additions, and time. This strongly affects structure and properties, and becomes of high importance, particularly when considering effects on structural integrity over long time periods. The fcc δ-phase deserves additional attention, not only in the context of understanding the electronic structure of Pu, but also as one of the few high-symmetry actinide phases that can be stabilized down to ambient pressure and room temperature by alloying it with trivalent elements. We will present results on recent work on aging of Pu-2at.%Ga and Pu-7at.%Ga alloys

  7. Structural evolution of Ni-20Cr alloy during ball milling of elemental powders

    Energy Technology Data Exchange (ETDEWEB)

    Lopez B, I.; Trapaga M, L. G. [IPN, Centro de Investigacion y de Estudios Avanzados, Unidad Queretaro, Libramiento Norponiente No. 2000, Juriquilla, 76230 Queretaro (Mexico); Martinez F, E. [Centro de Investigacion e Innovacion Tecnologica, Cerrada de Cecati s/n, Col. Santa Catarina Azcapotzalco, 02250 Mexico D. F. (Mexico); Zoz, H., E-mail: israelbaez@gmail.co [Zoz GmbH, D-57482, Wenden (Germany)

    2011-07-01

    The ball milling (B M) of blended Ni and Cr elemental powders was carried out in a Simoloyer performing on high-energy scale mode at maximum production to obtain a nano structured Ni-20Cr alloy. The phase transformations and structural changes occurring during mechanical alloying were investigated by X-ray diffraction (XRD) and optical microscopy (Om). A gradual solid solubility of Cr and the subsequent formation of crystalline metastable solid solutions described in terms of the Avrami-Ero fe ev kinetics model were calculated. The XRD analysis of the structure indicates that cumulative lattice strain contributes to the driving force for solid solution between Ni and Cr during B M. Microstructure evolution has shown, additionally to the lamellar length refinement commonly observed, the folding of lamellae in the final processing stage. Om observations revealed that the lamellar spacing of Ni rich zones reaches a steady value near 500 nm and almost disappears after 30 h of milling. (Author)

  8. Nuclear Fusion Blast and Electrode Lifetimes in a PJMIF Reactor

    Science.gov (United States)

    Thio, Y. C. Francis; Witherspoon, F. D.; Case, A.; Brockington, S.; Cruz, E.; Luna, M.; Hsu, S. C.

    2017-10-01

    We present an analysis and numerical simulation of the nuclear blast from the micro-explosion following the completion of the fusion burn for a baseline design of a PJMIF fusion reactor with a fusion gain of 20. The stagnation pressure from the blast against the chamber wall defines the engineering requirement for the structural design of the first wall and the plasma guns. We also present an analysis of the lifetimes of the electrodes of the plasma guns which are exposed to (1) the high current, and (2) the neutron produced by the fusion reactions. We anticipate that the gun electrodes are made of tungsten alloys as plasma facing components reinforced structurally by appropriate steel alloys. Making reasonable assumptions about the electrode erosion rate (100 ng/C transfer), the electrode lifetime limited by the erosion rate is estimated to be between 19 and 24 million pulses before replacement. Based on known neutron radiation effects on structural materials such as steel alloys and plasma facing component materials such as tungsten alloys, the plasma guns are expected to survive some 22 million shots. At 1 Hz, this equal to about 6 months of continuous operation before they need to be replaced. Work supported by Strong Atomics, LLC.

  9. First stage of the structural evolution of austenite in Cu-Al-Ni shape memory alloys

    International Nuclear Information System (INIS)

    Pelosin, V.; Gerland, M.; Riviere, A.

    2001-01-01

    Two shape memory Cu-Al-Ni alloys, a polycrystal and a single crystal, exhibiting a martensitic transformation close to 130 C (in the as-quenched state) have been studied. Specimens have been quenched after heat treatment at 850 C. The structural evolutions of the high temperature phase (austenite) have been studied for thermal treatments performed below 200 C. Investigations have been carried out using electrical resistivity measurements, TEM (transmission electron microscopy) observations and X-ray diffraction analysis. The main structural modifications are observed in the polycrystalline alloy and concern first, the reordering process of the austenite structure (B2→L2 1 ), and second, the precipitation of the (Cu 9 Al 4 ) γ 2 phase. In the single crystal alloy, the evolutions are very slight and localized on the structural defects. Particular attention is paid to the role of the quenched-in vacancy elimination on the observed mechanisms. In addition, the incidence of the structural evolution on the transformation temperatures is also discussed. (orig.)

  10. Nanoscale characterization of martensite structures in copper based shape memory alloys

    Energy Technology Data Exchange (ETDEWEB)

    Adiguzel, O, E-mail: oadiguzel@firat.edu.t [Firat University Department of Physics, 23169 Elazig (Turkey)

    2010-11-01

    Martensitic transformations are first order displacive transitions and occur in the materials on cooling from high temperature. Shape memory effect is an unusual property exhibited by certain alloy systems, and leads to martensitic transition. Copper-based alloys exhibit this property in beta phase field which possess simple bcc- structures, austenite structure at high-temperatures. As temperature is lowered the austenite undergoes martensitic transition following two ordering reactions, and structural changes in nanoscale govern this transition. Atomic movements are also confined to interatomic lengths in sub-{mu}m or angstrom scale in martensitic transformation. The formation of the layered structures in copper based alloys consists of shears and shear mechanism. Martensitic transformations occur in a few steps with the cooperative movement of atoms less than interatomic distances by means of lattice invariant shears on a {l_brace}110{r_brace} - type plane of austenite matrix which is basal plane or stacking plane of martensite. The lattice invariant shears occurs, in two opposite directions, <110> -type directions on the {l_brace}110{r_brace}-type plane. These shears gives rise to the formation of layered structure.

  11. L10 ordered structures in Al-Cu-(Mg) alloys at the early stages of elevated temperature aging

    Energy Technology Data Exchange (ETDEWEB)

    Fuzhong, X.; Mingpu, W.

    2016-07-01

    This study concerns the precipitation structures of Al-3Cu and Al-3Cu-1.78Mg (wt. %) alloys at the early stages of elevated temperature aging. The Al-3Cu and Al-3Cu-1.78 Mg alloys were solution treated at 540 °C and 500 °C for 2 h, respectively, and then aged at 190 °C for 2 min. The precipitation structures in aged Al-3Cu-(1.78Mg) alloys were characterized by Transmission Electron Microscopy (TEM) and High Resolution Transmission Electron Microscopy (HTREM). 001 zone axis Selected area electron diffraction patterns indicate that L10 ordered structures are formed in the two aged alloys. HRTEM experiments reveal the partial dislocations on the interfaces of L10 ordered structures. From comparing experimental results with that in the literature, it is concluded that the L10 ordered structures in aged Al-3Cu alloy consist of Al and Cu atoms, and they are comprised by Al, Cu and Mg atoms together in the aged Al-3Cu-1.78Mg alloy. On the basis of precipitate growing thermodynamics, it is thought the L10 ordered structures act as nuclei for GP zones in Al-Cu-(Mg) alloys during aging. (Author)

  12. L10 ordered structures in Al-Cu-(Mg) alloys at the early stages of elevated temperature aging

    International Nuclear Information System (INIS)

    Fuzhong, X.; Mingpu, W.

    2016-01-01

    This study concerns the precipitation structures of Al-3Cu and Al-3Cu-1.78Mg (wt. %) alloys at the early stages of elevated temperature aging. The Al-3Cu and Al-3Cu-1.78 Mg alloys were solution treated at 540 °C and 500 °C for 2 h, respectively, and then aged at 190 °C for 2 min. The precipitation structures in aged Al-3Cu-(1.78Mg) alloys were characterized by Transmission Electron Microscopy (TEM) and High Resolution Transmission Electron Microscopy (HTREM). 001 zone axis Selected area electron diffraction patterns indicate that L10 ordered structures are formed in the two aged alloys. HRTEM experiments reveal the partial dislocations on the interfaces of L10 ordered structures. From comparing experimental results with that in the literature, it is concluded that the L10 ordered structures in aged Al-3Cu alloy consist of Al and Cu atoms, and they are comprised by Al, Cu and Mg atoms together in the aged Al-3Cu-1.78Mg alloy. On the basis of precipitate growing thermodynamics, it is thought the L10 ordered structures act as nuclei for GP zones in Al-Cu-(Mg) alloys during aging. (Author)

  13. Stereological analysis of structure formation for solid WC-Co alloys in the process of carbide powder consolidation

    Energy Technology Data Exchange (ETDEWEB)

    Chernyavskij, K S

    1986-03-01

    Evolution of particle size distribution in carbide powders of different technological prehistory is studied in the process of their consolidation as a hard alloy. A successive estimate on identical preparations is used to study a structural powder->alloy transition. Temperature dependences of integral measures of the consolidated structure and characteristics of its heterogeneity are studied. It is shown that all studied structural rearrangements: formation of regular alternation of carbide and binding phases, development of particle-phase interfaces, change in size distribution - more intensely proceed in the high-temperature carbide base alloy.

  14. Incentives for the use of depleted uranium alloys as transport cask containment structure

    International Nuclear Information System (INIS)

    McConnell, P.; Salzbrenner, R.; Wellman, G.W.; Sorenson, K.B.

    1992-01-01

    Radioactive material transport casks use either lead or depleted uranium (DU) as gamma-ray shielding material. Stainless steel is conventionally used for structural containment. If a DU alloy had sufficient properties to guarantee resistance to failure during both nominal use and accident conditions to serve the dual-role of shielding and containment, the use of other structure materials (i.e., stainless steel) could be reduced. (It is recognized that lead can play no structural role.) Significant reductions in cask weight and dimensions could then be achieved perhaps allowing an increase in payload. The mechanical response of depleted uranium has previously not been included in calculations intended to show that DU-shielded transport casks will maintain their containment function during all conditions. This paper describesa two-part study of depleted uranium alloys: First, the mechanical behavior of DU alloys was determined in order to extend the limited set of mechanical properties reported in the literature. The mechanical properties measured include the tensile behavior the impact energy. Fracture toughness testing was also performed to determine the sensitivity of DU alloys to brittle fracture. Fracture toughness is the inherent material property which quantifies the fracmm resistance of a material. Tensile strength and ductility are significant in terms of other failure modes, however, as win be discussed. These mechanical properties were then input into finite element calculations of cask response to loading conditions to quantify the potential for claiming structural credit for DU. (The term ''structural credit'' describes whether a material has adequate properties to allow it to assume a positive role in withstanding structural loadings.)

  15. Structure of molten Bi-Sb-alloys by means of neutron diffraction

    International Nuclear Information System (INIS)

    Lamparter, P.; Knoll, W.; Steeb, S.

    1976-01-01

    The structural investigations with melts can be subdivided into two groups: The first group contains molten metals and molten alloys, and one can state that the structure of molten metals and of molten alloys nowadays is rather well understood. Interference functions of molten metals may be described by a hard sphere model. This is valid also for molten alloys with statistical distribution. For the second group, namely molten non-metals and molecular melts, the interference functions as well as the pair correlation functions are very offen rather complicated and not well understood. The present study is concerned with the transition region between these two groups. It is shown that the melts of the Bi-Sb system exhibit a change from metallic to non-metallic structure. Regarding the experimental details: the experiments were done with the two-axes spectrometer D 4 at the high-flux reactor at Grenoble. The containers consisted of cylindrical quartz tubes with a wall thickness of 0.1 cm. The furnace consisted of a direct-heated vanadium tube. The wavelength of the neutrons was 0.695 A. The final result is that the structure in molten Bi-Sb-alloys consists of primitive tetrahedra with coordination number 3. There are less tetrahedra in molten Bi than in molten Sb. Also with rising temperature the number of tetrahedra decreases. It is shown how to compose the coordination numbers of two structures to get the observed coordination number. The observed values are always the mean values of the two structures. (orig./HK) [de

  16. Incentives for the use of depleted uranium alloys as transport cask containment structure

    International Nuclear Information System (INIS)

    McConnell, P.; Salzbrenner, R.; Wellman, G.W.; Sorenson, K.B.

    1993-01-01

    Radioactive material transport casks use either lead or depleted uranium (DU) as gamma-ray shielding material. Stainless steel is conventionally used for structural containment. If a DU alloy had sufficient properties to guarantee resistance to failure during both normal use and accident conditions to serve the dual-role of shielding and containment, the use of other structural materials (i.e., stainless steel) could be reduced. (It is recognized that lead can play no structural role.) Significant reductions in cask weight and dimensions could then be achieved perhaps allowing an increase in payload. The mechanical response of depleted uranium has previously not been included in calculations intended to show that DU-shielded transport casks will maintain their containment function during all conditions. This paper describes a two-part study of depleted uranium alloys: First, the mechanical behavior of DU alloys was determined in order to extend the limited set of mechanical properties reported in the literature (Eckelmeyer, 1991). The mechanical properties measured include the tensile behavior the impact energy. Fracture toughness testing was also performed to determine the sensitivity of DU alloys to brittle fracture. Fracture toughness is the inherent material property which quantifies the fracture resistance of a material. Tensile strength and ductility are significant in terms of other failure modes, however, as will be discussed. These mechanical properties were then input into finite element calculations of cask response to loading conditions to quantify the potential for claiming structural credit for DU. (The term 'structural credit' describes whether a material has adequate properties to allow it to assume a positive role in withstanding structural loadings.) (J.P.N.)

  17. Materials program for magnetic fusion energy

    International Nuclear Information System (INIS)

    Zwilsky, K.M.; Cohen, M.M.; Finfgeld, C.R.; Reuther, T.C.

    1978-01-01

    The Magnetic Fusion Reactor Materials Program is currently operating at a level of $7.8M. The program is divided into four technical areas which cover both short and long term problems. These are: Alloy Development for Irradiation Performance, Damage Analysis and Fundamental Studies, Plasma-Materials Interaction, and Special Purpose Materials. A description of the program planning process, the continuing management structure, and the resulting documents is presented

  18. Determination of haplotypes at structurally complex regions using emulsion haplotype fusion PCR.

    Science.gov (United States)

    Tyson, Jess; Armour, John A L

    2012-12-11

    Genotyping and massively-parallel sequencing projects result in a vast amount of diploid data that is only rarely resolved into its constituent haplotypes. It is nevertheless this phased information that is transmitted from one generation to the next and is most directly associated with biological function and the genetic causes of biological effects. Despite progress made in genome-wide sequencing and phasing algorithms and methods, problems assembling (and reconstructing linear haplotypes in) regions of repetitive DNA and structural variation remain. These dynamic and structurally complex regions are often poorly understood from a sequence point of view. Regions such as these that are highly similar in their sequence tend to be collapsed onto the genome assembly. This is turn means downstream determination of the true sequence haplotype in these regions poses a particular challenge. For structurally complex regions, a more focussed approach to assembling haplotypes may be required. In order to investigate reconstruction of spatial information at structurally complex regions, we have used an emulsion haplotype fusion PCR approach to reproducibly link sequences of up to 1kb in length to allow phasing of multiple variants from neighbouring loci, using allele-specific PCR and sequencing to detect the phase. By using emulsion systems linking flanking regions to amplicons within the CNV, this led to the reconstruction of a 59kb haplotype across the DEFA1A3 CNV in HapMap individuals. This study has demonstrated a novel use for emulsion haplotype fusion PCR in addressing the issue of reconstructing structural haplotypes at multiallelic copy variable regions, using the DEFA1A3 locus as an example.

  19. Determination of haplotypes at structurally complex regions using emulsion haplotype fusion PCR

    Directory of Open Access Journals (Sweden)

    Tyson Jess

    2012-12-01

    Full Text Available Abstract Background Genotyping and massively-parallel sequencing projects result in a vast amount of diploid data that is only rarely resolved into its constituent haplotypes. It is nevertheless this phased information that is transmitted from one generation to the next and is most directly associated with biological function and the genetic causes of biological effects. Despite progress made in genome-wide sequencing and phasing algorithms and methods, problems assembling (and reconstructing linear haplotypes in regions of repetitive DNA and structural variation remain. These dynamic and structurally complex regions are often poorly understood from a sequence point of view. Regions such as these that are highly similar in their sequence tend to be collapsed onto the genome assembly. This is turn means downstream determination of the true sequence haplotype in these regions poses a particular challenge. For structurally complex regions, a more focussed approach to assembling haplotypes may be required. Results In order to investigate reconstruction of spatial information at structurally complex regions, we have used an emulsion haplotype fusion PCR approach to reproducibly link sequences of up to 1kb in length to allow phasing of multiple variants from neighbouring loci, using allele-specific PCR and sequencing to detect the phase. By using emulsion systems linking flanking regions to amplicons within the CNV, this led to the reconstruction of a 59kb haplotype across the DEFA1A3 CNV in HapMap individuals. Conclusion This study has demonstrated a novel use for emulsion haplotype fusion PCR in addressing the issue of reconstructing structural haplotypes at multiallelic copy variable regions, using the DEFA1A3 locus as an example.

  20. Effect of strontium on liquid structure of Al-Si hypoeutectic alloys using high-energy X-ray diffraction

    International Nuclear Information System (INIS)

    Srirangam, P.; Kramer, M.J.; Shankar, S.

    2011-01-01

    High-energy X-ray diffraction experiments were performed using a synchrotron beam source to investigate the effect of strontium on the liquid atomic structure of Al-Si hypoeutectic alloys. The high-temperature liquid diffraction experiments were carried out on Al alloys with 3, 7, 10 and 12.5 (eutectic) wt.% Si, respectively, with 0 and 0.04 wt.% addition of Sr to each of the alloys. Further, the diffraction data for all the alloys were obtained at various melt temperatures (5-220 K) above the respective liquidus temperature. It was observed that the addition of 0.04 wt.% Sr results in significant change in the liquid structure parameters, such as structure factor, pair distribution function, radial distribution function, coordination number and packing density, at any given melt temperature of the alloy. Salient observations were that, for any specific alloy and temperature, addition of Sr significantly decreases coordination number and packing density. Further, with the addition of Sr in the liquid alloy, the atomic coordination number and packing density increases with decreasing temperature and decreasing Si content of the alloy. The results coupled with prior knowledge have enabled an in-depth understanding of the nucleation environment of the solidifying phases, specifically the role of Sr in delaying the clustering tendencies (nucleation) of the eutectic Si phase.