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Sample records for high nickel alloys

  1. Nickel alloys and high-alloyed special stainless steels. Properties, manufacturing, applications. 4. compl. rev. ed.

    Energy Technology Data Exchange (ETDEWEB)

    Heubner, Ulrich; Kloewer, Jutta; Alves, Helena; Behrens, Rainer; Schindler, Claudius; Wahl, Volker; Wolf, Martin

    2012-07-01

    This book contains the following eight topics: 1. Nickel alloys and high-alloy special stainless steels - Material overview and metallurgical principles (U. Heubner); 2. Corrosion resistance of nickel alloys and high-alloy special stainless steels (U. Heubner); 3. Welding of nickel alloys and high-alloy special stainless steels (T. Hoffmann, M. Wolf); 4. High-temperature materials for industrial plant construction (J. Kloewer); 5. Nickel alloys and high-alloy special stainless steels as hot roll clad composites-a cost-effective alternative (C. Schindler); 6. Selected examples of the use of nickel alloys and high-alloy special stainless steels in chemical plants (H. Alves); 7. The use of nickel alloys and stainless steels in environmental engineering (V. Wahl); 8: Nickel alloys and high-alloy special stainless steels for the oil and gas industry (R. Behrens).

  2. Oxidation resistant iron and nickel alloys for high temperature use

    Science.gov (United States)

    Hill, V. L.; Misra, S. K.; Wheaton, H. L.

    1970-01-01

    Iron-base and nickel-base alloys exhibit good oxidation resistance and improved ductility with addition of small amounts of yttrium, tantalum /or hafnium/, and thorium. They can be used in applications above the operating temperatures of the superalloys, if high strength materials are not required.

  3. High strength nickel base alloy, WAZ-16, for applications up to 2200 F

    Science.gov (United States)

    Waters, W. J.; Freche, J. C.

    1974-01-01

    Alloy product is high strength, high temperature nickel base material with higher incipient melting temperature than all known nickel base alloys. It is microstructurally stable and has high impact resistance both before and after prolonged thermal exposure. It contains relatively few alloying constitutents and low content of expensive and rare metals.

  4. Advanced nickel base alloys for high strength, corrosion applications

    Science.gov (United States)

    Flinn, John E.

    1998-01-01

    Improved nickel-base alloys of enhanced strength and corrosion resistance, produced by atomization of an alloy melt under an inert gas atmosphere and of composition 0-20Fe, 10-30Cr, 2-12Mo, 6 max. Nb, 0.05-3 V, 0.08 max. Mn, 0.5 max. Si, less than 0.01 each of Al and Ti, less than 0.05 each of P and S, 0.01-0.08C, less than 0.2N, 0.1 max. 0, bal. Ni.

  5. Study of fluoride corrosion of nickel alloys

    Science.gov (United States)

    Gunther, W. H.; Steindler, M. J.

    1969-01-01

    Report contains the results of an investigation of the corrosion resistance of nickel and nickel alloys exposed to fluorine, uranium hexafluoride, and volatile fission product fluorides at high temperatures. Survey of the unclassified literature on the subject is included.

  6. Nickel-base alloy forgings for advanced high temperature power plants

    Energy Technology Data Exchange (ETDEWEB)

    Donth, B.; Diwo, A.; Blaes, N.; Bokelmann, D. [Saarschmiede GmbH Freiformschmiede, Voelklingen (Germany)

    2008-07-01

    The strong efforts to reduce the CO{sub 2} emissions lead to the demand for improved thermal efficiency of coal fired power plants. An increased thermal efficiency can be realised by higher steam temperatures and pressures in the boiler and the turbine. The European development aims for steam temperatures of 700 C which requires the development and use of new materials and also associated process technology for large components. Temperatures of 700 C and above are too high for the application of ferritic steels and therefore only Nickel-Base Alloys can fulfill the required material properties. In particular the Nickel-Base Alloy A617 is the most candidate alloy on which was focused the investigation and development in several German and European programs during the last 10 years. The goal is to verify and improve the attainable material properties and ultrasonic detectability of large Alloy 617 forgings for turbine rotors and boiler parts. For many years Saarschmiede has been manufacturing nickel and cobalt alloys and is participating the research programs by developing the manufacturing routes for large turbine rotor forgings up to a maximum diameter of 1000 mm as well as for forged tubes and valve parts for the boiler side. The experiences in manufacturing and testing of very large forgings made from nickel base alloys for 700 C steam power plants are reported. (orig.)

  7. High specialty stainless steels and nickel alloys for FGD dampers

    Energy Technology Data Exchange (ETDEWEB)

    Herda, W.R.; Rockel, M.B.; Grossmann, G.K. [Krupp VDM GmbH, Werdohl (Germany); Starke, K. [Mannesmann-Seiffert GmbH, Beckum (Germany)

    1997-08-01

    Because of process design and construction, FGD installations normally have bypass ducts, which necessitates use of dampers. Due to corrosion from acid dew resulting from interaction of hot acidic flue gases and colder outside environments, carbon steel cannot be used as construction material under these specific conditions. In the past, commercial stainless steels have suffered by pitting and crevice corrosion and occasionally failed by stress corrosion cracking. Only high alloy specialty super-austenitic stainless steels with 6.5% Mo should be used and considered for this application. Experience in Germany and Europe has shown that with regard to safety and life cycle cost analysis as well as providing a long time warranty, a new specialty stainless steel, alloy 31--UNS N08031--(31 Ni, 27 Cr, 6.5 Mo, 0.2 N) has proven to be the best and most economical choice. Hundreds of tons in forms of sheet, rod and bar, as well as strip (for damper seals) have been used and installed in many FGD installations throughout Europe. Under extremely corrosive conditions, the new advanced Ni-Cr-Mo alloy 59--UNS N06059--(59 Ni, 23 Cr, 16 Mo) should be used. This paper describes qualification and workability of these alloys as pertains to damper applications. Some case histories are also provided.

  8. Calculation of the high-temperature strength of complexly alloyed nickel alloys using equations of the system of nonpolarized ionic radii

    Science.gov (United States)

    Ovsepyan, S. V.; Lomberg, B. S.; Baburina, E. V.

    1995-06-01

    Modern complexly alloyed high-temperature nickel-base alloys contain up to 14 alloying elements. The complex composition ensures fulfillment of strict and often contradictory requirements imposed on the materials of critical parts of gas turbine engines (GTE). However, multi-component alloying creates considerable difficulties in the development of new compositions with specified characteristics or in the optimization of existing alloys. The present work is devoted to calculating the high-temperature strength of nickel alloys by means of the system of nonpolarized ionic radii (SNIR).

  9. The strengthening mechanism of a nickel-based alloy after laser shock processing at high temperatures

    Directory of Open Access Journals (Sweden)

    Yinghong Li, Liucheng Zhou, Weifeng He, Guangyu He, Xuede Wang, Xiangfan Nie, Bo Wang, Sihai Luo and Yuqin Li

    2013-01-01

    Full Text Available We investigated the strengthening mechanism of laser shock processing (LSP at high temperatures in the K417 nickel-based alloy. Using a laser-induced shock wave, residual compressive stresses and nanocrystals with a length of 30–200 nm and a thickness of 1 μm are produced on the surface of the nickel-based alloy K417. When the K417 alloy is subjected to heat treatment at 900 °C after LSP, most of the residual compressive stress relaxes while the microhardness retains good thermal stability; the nanocrystalline surface has not obviously grown after the 900 °C per 10 h heat treatment, which shows a comparatively good thermal stability. There are several reasons for the good thermal stability of the nanocrystalline surface, such as the low value of cold hardening of LSP, extreme high-density defects and the grain boundary pinning of an impure element. The results of the vibration fatigue experiments show that the fatigue strength of K417 alloy is enhanced and improved from 110 to 285 MPa after LSP. After the 900 °C per 10 h heat treatment, the fatigue strength is 225 MPa; the heat treatment has not significantly reduced the reinforcement effect. The feature of the LSP strengthening mechanism of nickel-based alloy at a high temperature is the co-working effect of the nanocrystalline surface and the residual compressive stress after thermal relaxation.

  10. High gas velocity oxidation and hot corrosion testing of oxide dispersion-strengthened nickel-base alloys

    Science.gov (United States)

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

    1975-01-01

    Several oxide dispersion strengthened (ODS) nickel-base alloys were tested in high velocity gases for cyclic oxidation resistance at temperatures to 1200 C and times to 500 hours and for hot corrosion resistance at 900 C for 200 hours. Nickel-chromium-aluminum ODS alloys were found to have superior resistance to oxidation and hot corrosion when compared to bare and coated nickel-chromium ODS alloys. The best of the alloys tested had compositions of nickel - 15.5 to 16 weight percent chromium with aluminum weight percents between 4.5 and 5.0. All of the nickel-chromium-aluminum ODS materials experienced small weight losses (less than 16 mg/sq cm).

  11. Stress corrosion cracking of several high strength ferrous and nickel alloys

    Science.gov (United States)

    Nelson, E. E.

    1971-01-01

    The stress corrosion cracking resistance of several high strength ferrous and nickel base alloys has been determined in a sodium chloride solution. Results indicate that under these test conditions Multiphase MP35N, Unitemp L605, Inconel 718, Carpenter 20Cb and 20Cb-3 are highly resistant to stress corrosion cracking. AISI 410 and 431 stainless steels, 18 Ni maraging steel (250 grade) and AISI 4130 steel are susceptible to stress corrosion cracking under some conditions.

  12. Heat resistant nickel base alloy excellent in workability and high temperature strength properties

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    Susukida, H.; Itoh, H.; Kawai, H.; Kojima, T.; Sahira, K.; Takeiri, T.; Tsuji, I.; Yuge, M.

    1984-10-02

    A heat resistant nickel base alloy which is excellent in not only hot and cold workability but also high temperature strength properties and which also possesses satisfactory oxidation resistance. The nickel base alloy consists essentially of 0.001-0.15 percent carbon, 0.0005-0.05 percent calcium, 20.0-126.0 percent chromium, 4.7-9.4 percent cobalt, 5.0-16.0 percent molybdenum, 0.5-4.0 percent tungsten, with the total of molybdenum plus tungsten being from 9.0 to 16.5 percent, and the balance nickel and inevitable impurities. The alloy may further contain one selected from the group consisting of (1) 0.3-1.5 percent aluminum and 0.1-1.0 percent titanium, (2) 0.001-0.30 percent at least one of yttrium and rare earth elements, and (3) 0.001-1.0 percent at least one of niobium, vanadium and tantalum, whereby the aforementioned characteristics are further enhanced.

  13. Production of High-Purity Anhydrous Nickel(II) Perrhenate for Tungsten-Based Sintered Heavy Alloys.

    Science.gov (United States)

    Leszczyńska-Sejda, Katarzyna; Benke, Grzegorz; Kopyto, Dorota; Majewski, Tomasz; Drzazga, Michał

    2017-04-24

    This paper presents a method for the production of high-purity anhydrous nickel(II) perrhenate. The method comprises sorption of nickel(II) ions from aqueous nickel(II) nitrate solutions, using strongly acidic C160 cation exchange resin, and subsequent elution of sorbed nickel(II) ions using concentrated perrhenic acid solutions. After the neutralization of the resulting rhenium-nickel solutions, hydrated nickel(II) perrhenate is then separated and then dried at 160 °C to obtain the anhydrous form. The resulting compound is reduced in an atmosphere of dissociated ammonia in order to produce a Re-Ni alloy powder. This study provides information on the selected properties of the resulting Re-Ni powder. This powder was used as a starting material for the production of 77W-20Re-3Ni heavy alloys. Microstructure examination results and selected properties of the produced sintered heavy alloys were compared to sintered alloys produced using elemental W, Re, and Ni powders. This study showed that the application of anhydrous nickel(II) perrhenate in the production of 77W-20Re-3Ni results in better properties of the sintered alloys compared to those made from elemental powders.

  14. Production of High-Purity Anhydrous Nickel(II Perrhenate for Tungsten-Based Sintered Heavy Alloys

    Directory of Open Access Journals (Sweden)

    Katarzyna Leszczyńska-Sejda

    2017-04-01

    Full Text Available This paper presents a method for the production of high-purity anhydrous nickel(II perrhenate. The method comprises sorption of nickel(II ions from aqueous nickel(II nitrate solutions, using strongly acidic C160 cation exchange resin, and subsequent elution of sorbed nickel(II ions using concentrated perrhenic acid solutions. After the neutralization of the resulting rhenium-nickel solutions, hydrated nickel(II perrhenate is then separated and then dried at 160 °C to obtain the anhydrous form. The resulting compound is reduced in an atmosphere of dissociated ammonia in order to produce a Re-Ni alloy powder. This study provides information on the selected properties of the resulting Re-Ni powder. This powder was used as a starting material for the production of 77W-20Re-3Ni heavy alloys. Microstructure examination results and selected properties of the produced sintered heavy alloys were compared to sintered alloys produced using elemental W, Re, and Ni powders. This study showed that the application of anhydrous nickel(II perrhenate in the production of 77W-20Re-3Ni results in better properties of the sintered alloys compared to those made from elemental powders.

  15. Kinetics of passivation of a nickel-base alloy in high temperature water

    Energy Technology Data Exchange (ETDEWEB)

    Machet, A. [Laboratoire de Physico-Chimie des Surfaces, CNRS-ENSCP (UMR 7045), Ecole Nationale Superieure de Chimie de Paris, Universite Pierre et Marie Curie, F-75231 Paris cedex 05 (France)]|[Framatome ANP, Tour AREVA, F-92084 Paris-la-Defense (France); Galtayries, A.; Zanna, S.; Marcus, P. [Laboratoire de Physico-Chimie des Surfaces, CNRS-ENSCP (UMR 7045), Ecole Nationale Superieure de Chimie de Paris, Universite Pierre et Marie Curie, F-75231 Paris cedex 05 (France); Jolivet, P.; Scott, P. [Framatome ANP, Tour AREVA, F-92084 Paris-la-Defense (France); Foucault, M.; Combrade, P. [Framatome ANP, Centre Technique, F-71205 Le Creusot (France)

    2004-07-01

    The kinetics of passivation and the composition of the surface oxide layer, in high temperature and high pressure water, of a nickel-chromium-iron alloy (Alloy 600) have been investigated by X-ray Photoelectron Spectroscopy (XPS). The samples have been exposed for short (0.4 - 8.2 min) and longer (0 - 400 hours) time periods to high temperature (325 deg. C) and high pressure water (containing boron and lithium) under controlled hydrogen pressure. The experiments were performed in two types of autoclaves: a novel autoclave dedicated to short time periods and a classic static autoclave for the longer exposures. In the initial stage of passivation, a continuous ultra-thin layer of chromium oxide (Cr{sub 2}O{sub 3}) is rapidly formed on the surface with an external layer of chromium hydroxide. For longer times of passivation, the oxide layer is in a duplex form with an internal chromium oxide layer and an external layer of nickel hydroxide. The growth of the internal Cr{sub 2}O{sub 3} oxide layer has been fitted by three classical models (parabolic, logarithmic and inverse logarithmic laws) for the short passivation times, and the growth curves have been extrapolated to longer passivation periods. The comparison with the experimental results reveals that the kinetics of passivation of Alloy 600 in high temperature and high pressure water, for passivation times up to 400 hours, is well fitted by a logarithmic growth law. (authors)

  16. Mechanical properties of Inconel 718 and Nickel 201 alloys after thermal histories simulating brazing and high temperature service

    Science.gov (United States)

    James, W. F.

    1985-01-01

    An experimental investigation was made to evaluate two nickel base alloys (Nickel-201 and Inconel-718) in three heat treated conditions. These conditions were: (1) annealed; (2) after thermal exposure simulating a braze cycle; and (3) after a thermal exposure simulating a braze cycle plus one operational lifetime of high temperature service. For the Nickel-201, two different braze cycle temperatures were evaluated. A braze cycle utilizing a lower braze temperature resulted in less grain growth for Nickel-201 than the standard braze cycle used for joining Nickel-201 to Inconel-718. It was determined, however, that Nickel-201, was marginal for temperatures investigated due to large grain growth. After the thermal exposures described above, the mechanical properties of Nickel-201 were degraded, whereas similar exposure on Inconel-718 actually strengthened the material compared with the annealed condition. The investigation included tensile tests at both room temperature and elevated temperatures, stress-rupture tests, and metallographic examination.

  17. Nickel Alloy Catalysts for the Anode of a High Temperature PEM Direct Propane Fuel Cell

    Directory of Open Access Journals (Sweden)

    Shadi Vafaeyan

    2014-01-01

    Full Text Available High temperature polymer electrode membrane fuel cells that use hydrocarbon as the fuel have many theoretical advantages over those that use hydrogen. For example, nonprecious metal catalysts can replace platinum. In this work, two of the four propane fuel cell reactions, propane dehydrogenation and water dissociation, were examined using nickel alloy catalysts. The adsorption energies of both propane and water decreased as the Fe content of Ni/Fe alloys increased. In contrast, they both increased as the Cu content of Ni/Cu alloys increased. The activation energy for the dehydrogenation of propane (a nonpolar molecule changed very little, even though the adsorption energy changed substantially as a function of alloy composition. In contrast, the activation energy for dissociation of water (a molecule that can be polarized decreased markedly as the energy of adsorption decreased. The different relationship between activation energy and adsorption energy for propane dehydrogenation and water dissociation alloys was attributed to propane being a nonpolar molecule and water being a molecule that can be polarized.

  18. The machinability of nickel-based alloys in high-pressure jet assisted (HPJA turning

    Directory of Open Access Journals (Sweden)

    D. Kramar

    2013-10-01

    Full Text Available Due to their mechanical, thermal and chemical properties, nickel-based alloys are generally included among materials that are hard to machine. An experimental study has been performed to investigate the capabilities of conventional and high-pressure jet assisted (HPJA turning of hard-to-machine materials, namely Inconel 718. The capabilities of different hard turning procedures are compared by means of chip breakability. The obtained results show that HPJA method offers a significant increase in chip breakability, under the same cutting conditions (cutting speed, feed rate, depth of cut.

  19. Nickel, cobalt, and their alloys

    CERN Document Server

    2000-01-01

    This book is a comprehensive guide to the compositions, properties, processing, performance, and applications of nickel, cobalt, and their alloys. It includes all of the essential information contained in the ASM Handbook series, as well as new or updated coverage in many areas in the nickel, cobalt, and related industries.

  20. High-temperature, high-frequency fretting fatigue of a single crystal nickel alloy

    Science.gov (United States)

    Matlik, John Frederick

    Fretting is a structural damage mechanism arising from a combination of wear, corrosion, and fatigue between two nominally clamped surfaces subjected to an oscillatory loading. A critical location for fretting induced damage has been identified at the blade/disk and blade/damper interfaces of gas turbine engine turbomachinery and space propulsion components. The high-temperature, high-frequency loading environment seen by these components lead to severe stress gradients at the edge-of-contact that could potentially foster crack growth leading to component failure. These contact stresses drive crack nucleation in fretting and are very sensitive to the geometry of the contacting bodies, the contact loads, materials, temperature, and contact surface tribology (friction). To diagnose the threat that small and relatively undetectable fretting fatigue cracks pose to damage tolerance and the ensuing structural integrity of aerospace components, a strong motivation exists to develop a quantitative mechanics based understanding of fretting crack nucleation in advanced aerospace alloys. In response to this need, the objective of this work is to characterize the fretting behavior exhibited by a polycrystalline/single crystal nickel contact subjected to elevated frequency and temperature. The effort to meet this objective is two fold: (1) to develop a well-characterized experimental fretting rig to investigate fretting behavior of advanced aerospace alloys at high frequency and high temperature, and (2) to develop the associated contact modeling tools for calculating contact stresses given in-situ experimentally measured remote contact loads. By coupling the experimental results and stress analysis, this effort aims to correlate the fretting crack nucleation behavior with the local contact stresses calculated from the devised three dimensional, anisotropic, dissimilar material contact model. The experimental effort is first motivated by a survey of recent fretting issues and

  1. Hydrogen induced cracking tests of high strength steels and nickel-iron base alloys using the bolt-loaded specimen

    Energy Technology Data Exchange (ETDEWEB)

    Vigilante, G.N.; Underwood, J.H.; Crayon, D.; Tauscher, S.; Sage, T.; Troiano, E. [Army Armament RD and E Center, Watervliet, NY (United States). Benet Labs.

    1997-12-31

    Hydrogen induced cracking tests were conducted on high strength steels and nickel-iron base alloys using the constant displacement bolt-loaded compact specimen. The bolt-loaded specimen was subjected to both acid and electrochemical cell environments in order to produce hydrogen. The materials tested were A723, Maraging 200, PH 13-8 Mo, Alloy 718, Alloy 706, and A286, and ranged in yield strength from 760--1400 MPa. The effects of chemical composition, refinement, heat treatment, and strength on hydrogen induced crack growth rates and thresholds were examined. In general, all high strength steels tested exhibited similar crack growth rates and thresholds were examined. In general, all high strength steels tested exhibited similar crack growth rates and threshold levels. In comparison, the nickel-iron base alloys tested exhibited up to three orders of magnitude lower crack growth rates than the high strength steels tested. It is widely known that high strength steels and nickel base alloys exhibit different crack growth rates, in part, because of their different crystal cell structure. In the high strength steels tested, refinement and heat treatment had some effect on hydrogen induced cracking, though strength was the predominant factor influencing susceptibility to cracking. When the yield strength of one of the high strength steels tested was increased moderately, from 1130 MPa to 1275 MPa, the incubation times decreased by over two orders of magnitude, the crack growth rates increased by an order of magnitude, and the threshold stress intensity was slightly lower.

  2. Pulse Reversal Plating of Nickel and Nickel Alloys for MEMS

    DEFF Research Database (Denmark)

    Tang, Peter Torben

    2001-01-01

    Pulse plating has previously been reported to improve the properties of nickel and nickel alloy deposits. Typically, focus has been on properties such as grain size, hardness and smoothness. When pulse plating is to be utilized for micro electromechanical systems (MEMS), internal stress...... and material distribution is even more important. Using a bath consisting mostly of nickel chloride, pulse reversal plating of both pure nickel and nickel-cobalt alloys has been used to fabricate tools for micro-injection molding. Pulse reversal plating of ternary soft-magnetic alloys, comprising 45-65 percent...

  3. Zirconium modified nickel-copper alloy

    Science.gov (United States)

    Whittenberger, J. D. (Inventor)

    1977-01-01

    An improved material for use in a catalytic reactor which reduces nitrogen oxide from internal combustion engines is in the form of a zirconium-modified, precipitation-strengthened nickel-copper alloy. This material has a nominal composition of Ni-30 Cu-0.2 Zr and is characterized by improved high temperature mechanical properties.

  4. Nickel aluminide alloys with improved weldability

    Science.gov (United States)

    Santella, M.L.; Goodwin, G.M.

    1995-05-09

    Weldable nickel aluminide alloys which are essentially free, if not entirely free, of weld hot cracking are provided by employing zirconium concentrations in these alloys of greater than 2.6 wt. % or sufficient to provide a substantial presence of Ni--Zr eutectic phase in the weld so as to prevent weld hot cracking. Weld filler metals formed from these so modified nickel aluminide alloys provide for crack-free welds in previously known nickel aluminide alloys. 5 figs.

  5. Passivation and corrosion of the high performance materials alloy 33, alloy 31 and nickel in LiBr solution at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Igual Munoz, A.; Garcia Anton, J.; Guinon, J.L.; Perez Herranz, V. [Departamento de Ingenieria Quimica y Nuclear. E.T.S. Industriales, Universidad Politecnica de Valencia, P.O. Box 22012, E-46071 Valencia (Spain)

    2004-07-01

    Aqueous solutions containing high concentrations of Lithium Bromide are employed as absorbent solutions for almost all types of heating and refrigerating absorption systems that use natural gas or steam as energy sources. LiBr solutions can cause serious corrosion problems in common metallic components. The objective of the present work was to study the corrosion resistance of new high alloyed materials in commercial LiBr heavy brine solution (which contains chromate as inhibitor), at different temperatures (25, 30, 40, 50, 60, 70 and 80 deg. C). The materials tested were stainless steels Alloy 33 (UNS R20033), a new corrosion resistant austenitic material alloyed with nominally (wt%) 33 Cr, 32 Fe, 31 Ni; Nicrofer 3127 hMo-alloy 31 (UNS N08031), an iron-nickel-chromium-molybdenum alloy with nitrogen; and pure Nickel. Corrosion resistance was estimated from the cyclic potentiodynamic polarization curves, comparing OCP values, calculating corrosion potentials and current rates from Tafel analysis; in order to characterize the passivating behaviour of the alloys the study was completed with the analysis of the pitting potentials, passivating current and re-passivating properties at the temperatures under study. Passivating properties are well observed in all the samples in commercial LiBr solution at all temperatures. In these cases, passivation properties decrease with temperature. (authors)

  6. Braze Alloy Development for Fast Epitaxial High-Temperature Brazing of Single-Crystalline Nickel-Based Superalloys

    Science.gov (United States)

    Laux, B.; Piegert, S.; Rösler, J.

    2009-01-01

    For the repair of single-crystalline turbine components, fabricated from nickel-based superalloys, a new high-temperature brazing technology has been developed. Cracks in single-crystalline parts can be repaired by reproducing the single-crystalline microstructure over the complete gap width within very short brazing times. Nickel-manganese-based alloys were identified as systems that provide very high, epitaxial solidification rates. In contrast to commonly used braze alloys, such as nickel-boron or nickel-silicon systems, the process is not completely diffusion controlled but works with consolute systems. For brazing experiments 300- μm-wide parallel gaps as well as V-shaped gaps with a maximum width of 250 μm were used. A complete epitaxial solidification, that is, the absence of large-angle grain boundaries, could be achieved within brazing times, being up to 100 times shorter compared to commonly used transient-liquid-phase bonding technologies. To quantify the misorientation relative to the base material and the composition within and near the filled gaps, the results of the brazing experiments were visualized by means of light microscopy and scanning electron microscopy (SEM). Furthermore, electron backscatter diffraction (EBSD) analyses and energy dispersive X-ray (EDX) analyses were conducted.

  7. Using the PSCPCSP computer software for optimization of the composition of industrial alloys and development of new high-temperature nickel-base alloys

    Science.gov (United States)

    Rtishchev, V. V.

    1995-11-01

    Using computer programs some foreign firms have developed new deformable and castable high-temperature nickel-base alloys such as IN, Rene, Mar-M, Udimet, TRW, TM, TMS, TUT, with equiaxial, columnar, and single-crystal structures for manufacturing functional and nozzle blades and other parts of the hot duct of transport and stationary gas-turbine installations (GTI). Similar investigations have been carried out in Russia. This paper presents examples of the use of the PSCPCSP computer software for a quantitative analysis of structural und phase characteristics and properties of industrial alloys with change (within the grade range) in the concentrations of the alloying elements for optimizing the composition of the alloys and regimes of their heat treatment.

  8. AN ELECTROPLATING METHOD OF FORMING PLATINGS OF NICKEL, COBALT, NICKEL ALLOYS OR COBALT ALLOYS

    DEFF Research Database (Denmark)

    1997-01-01

    An electroplating method of forming platings of nickel, cobalt, nickel alloys or cobalt alloys with reduced stresses in an electrodepositing bath of the type: Watt's bath, chloride bath or a combination thereof, by employing pulse plating with periodic reverse pulse and a sulfonated naphthalene...... additive. This method makes it possible to deposit nickel, cobalt, nickel or cobalt platings without internal stresses....

  9. Pulse reversal plating of nickel alloys

    DEFF Research Database (Denmark)

    Tang, Peter Torben

    2007-01-01

    Pulse plating has previously been reported to improve the properties of nickel and nickel alloy deposits. Typically, focus has been on properties such as grain size, hardness and smoothness. When pulse plating is to be utilised for microtechnologies such as microelectromechanical systems (MEMS......), internal stress and material distribution are even more important. With baths based upon nickel chloride, and nickel and cobalt chlorides, pulse reversal plating of both pure nickel and nickel-cobalt alloys has been used to fabricate tools for microinjection moulding. Pulse reversal plating of ternary soft...

  10. Nickel-base alloys for severe environments

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, R.K.; Flower, H.L. [Inco Alloys International Inc., Huntington, WV (United States); Hack, G.A.J. [Inco Alloys Ltd., Hereford (United Kingdom); Isobe, S. [Daido Steel Co. Ltd., Nagoya (Japan)

    1996-03-01

    Inconel alloys MA754 and MA758 are nickel-base, oxide dispersion-strengthened superalloys made by mechanical alloying. The simple nickel-chromium matrix, when combined with the strengthening effect of the yttrium oxide dispersoid during mechanical alloys, provides excellent creep properties, resistance to thermal fatigue, and surface stability suitable for operation without protective coatings. Gas turbine engine components are primary applications for alloy MA754, but this aerospace alloy has been applied in many other products that operate in severe conditions, and alloy MA758 was developed specifically for aggressive, elevated temperature industrial environments. Billets for large bar and plate are typically consolidated by hot isostatic pressing (HIP), because this technology allows production of forms suitable for a variety of industrial components. Material consolidated by HIP and conventionally worked by extrusion and hot rolling generally exhibits properties that are more isotropic than those of material consolidated by extrusion. However, the degree of anisotropy depends strongly on the specific processing of the consolidated billet. This article describes production of new mill shapes from HIP billets, and reviews current and potential applications such as skid rails for high-temperature walking-beam furnaces, heat treating furnace parts, equipment for handling molten glass, and furnace tubes.

  11. Static and dynamic cyclic oxidation of 12 nickel-, cobalt-, and iron-base high-temperature alloys

    Science.gov (United States)

    Barrett, C. A.; Johnston, J. R.; Sanders, W. A.

    1978-01-01

    Twelve typical high-temperature nickel-, cobalt-, and iron-base alloys were tested by 1 hr cyclic exposures at 1038, 1093, and 1149 C and 0.05 hr exposures at 1093 C. The alloys were tested in both a dynamic burner rig at Mach 0.3 gas flow and in static air furnace for times up to 100 hr. The alloys were evaluated in terms of specific weight loss as a function of time, and X-ray diffraction analysis and metallographic examination of the posttest specimens. A method previously developed was used to estimate specific metal weight loss from the specific weight change of the sample. The alloys were then ranked on this basis. The burner-rig test was more severe than a comparable furnace test and resulted in an increased tendency for oxide spalling due to volatility of Cr in the protective scale and the more drastic cooling due to the air-blast quench of the samples. Increased cycle frequency also increased the tendency to spall for a given test exposure. The behavior of the alloys in both types of tests was related to their composition and their tendency to form scales. The alloys with the best overall behavior formed alpha-Al2O3 aluminate spinels.

  12. Influence of Crucible Materials on High-temperature Properties of Vacuum-melted Nickel-chromium-cobalt Alloy

    Science.gov (United States)

    Decker, R F; Rowe, John P; Freeman, J W

    1957-01-01

    A study of the effect of induction-vacuum-melting procedure on the high-temperature properties of a titanium-and-aluminum-hardened nickel-base alloy revealed that a major variable was the type of ceramic used as a crucible. Reactions between the melt and magnesia or zirconia crucibles apparently increased high-temperature properties by introducing small amounts of boron or zirconium into the melts. Heats melted in alumina crucibles had relatively low rupture life and ductility at 1,600 F and cracked during hot-working as a result of deriving no boron or zirconium from the crucible.

  13. Dendritic Solidification in a Copper Nickel Alloy

    OpenAIRE

    DÜNDAR, Sacit

    2014-01-01

    The distribution of nickel in dendrite arms and in interdendritic regions of copper-10% nickel alloy solidified under production conditions designed to provide 4 different cooling rates was investigated. The results indicate that at different rates of solidification undercooling, diffusion and convection mechanisms affect the microsegregation of nickel and copper in the cast materials to various extents.

  14. Current Status of Development of High Nickel Low Alloy Steels for Commercial Reactor Pressure Vessel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Chul; Lee, B. S.; Park, S. G.; Lee, K. H. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2008-12-15

    SA508 Gr.3 Mn-Mo-Ni low alloy steels have been used for nuclear reactor pressure vessel steels up to now. Currently, the design goal of nuclear power plant is focusing at larger capacity and longer lifetime. Requirements of much bigger pressure vessels may cause critical problems in the manufacturing stage as well as for the welding stage. Application of higher strength steel may be required to overcome the technical problems. It is known that a higher strength and fracture toughness of low alloy steels such as SA508 Gr.4N low alloy steel could be achieved by increasing the Ni and Cr contents. Therefore, SA508 Gr.4N low alloy steel is very attractive as eligible RPV steel for the next generation PWR systems. In this report, we propose the possibility of SA508 Gr.4N low alloy steel for an application of next generation commercial RPV, based on the literature research result about development history of the RPV steels and SA508 specification. In addition, we have surveyed the research result of HSLA(High Strength Low Alloy steel), which has similar chemical compositions with SA508 Gr.4N, to understand the problems and the way of improvement of SA508 Gr.4N low alloy steel. And also, we have investigated eastern RPV steel(WWER-1000), which has higher Ni contents compared to western RPV steel.

  15. High temperature corrosion of nickel-base alloys in environments containing alkali sulphate

    Energy Technology Data Exchange (ETDEWEB)

    Pettersson, Rachel; Flyg, Jesper; Caddeo, Sophie [Corrosion and Metals Research Institute, KIMAB, Stockholm (Sweden); Karlsson, Fredrik [Siemens Industrial Turbomachinery, Finspong (Sweden)

    2007-02-15

    This work is directed towards producing data to assist in lifetime assessment of components in gas turbines run in severely polluted industrial environments where the main corrosive species is SO{sub 2}, which can condense to form alkali sulphates. Corrosion rates have been measured for the base materials, in order to assess the worst-case scenario, in which cracks or other damage has occurred to the protective coating. The information is expected to be of value to manufacturers, owners and inspectors of gas turbines. Six nickel-base superalloys were subject to thermal cycles of 160 hours duration, and 0.8mg/cm{sup 2} of 20 mol % Na{sub 2}SO{sub 4} + 80mol% K{sub 2}SO{sub 4} was applied before each cycle. The test temperatures were 850 deg C and 900 deg C, with maximum test durations of 24 cycles and 12 cycles respectively. The metal loss was assessed by metallography of cross sections and the sulphidation attack was found to be very uneven. Mass change data indicated that the corrosion process was largely linear in character, and probability plots and estimations of the propagation rate of corrosion based on the linear growth assumption were produced. The performance of the alloys increased with increasing chromium content. The single crystal materials CMSX4 and MD2 showed such high corrosion rates that their use in severely contaminated industrial environments is considered inadvisable. The best performance was shown by Inconel 939 and Inconel 6203, so that even if cracks occur in the protective coating, a reasonable remaining lifetime can be expected for these materials. Sulphide formation occurred at the reaction front in all cases and mixed sulphides such as Ta-Ni or Ti-Nb sulphides were often present. The work has news value since very little long-term data is currently available for materials performance in severely sulphidising environments. The project goals in terms of exposures and metrology have been fully realised. Contributions have been made to the

  16. Pulse reversal plating of nickel-cobalt alloys

    DEFF Research Database (Denmark)

    Tang, Peter Torben; Jaskula, M.; Kubiczek, M.

    2009-01-01

    extreme demands, in terms of tool accuracy, process temperature and tool wear, are requested. In order to meet these demands, electroforming of hard nickel alloys is an obvious way forward. This paper presents several electrolytes from which it is possible to deposit nickel-cobalt alloys with high...... hardness (>550 HV), low internal stress and easy maintenance. Moreover, different organic complexing agents - as well as alternatives to boric acid - have been investigated....

  17. Corrosion behavior of nickel-containing alloys in artificial sweat.

    Science.gov (United States)

    Randin, J P

    1988-07-01

    The corrosion resistance of various nickel-containing alloys was measured in artificial sweat (perspiration) using the Tafel extrapolation method. It was found that Ni, CuNi 25 (coin alloy), NiAl (colored intermetallic compounds), WC + Ni (hard metal), white gold (jewelry alloy), FN42 and Nilo Alby K (controlled expansion alloys), and NiP (electroless nickel coating) are in an active state and dissolve readily in oxygenated artificial sweat. By contrast, austenitic stainless steels, TiC + Mo2C + Ni (hard metal), NiTi (shape-memory alloy), Hastelloy X (superalloy), Phydur (precipitation hardening alloy), PdNi and SnNi (nickel-containing coatings) are in a passive state but may pit under certain conditions. Cobalt, Cr, Ti, and some of their alloys were also investigated for the purpose of comparison. Cobalt and its alloys have poor corrosion resistance except for Stellite 20. Chromium and high-chromium ferritic stainless steels have a high pitting potential but the latter are susceptible to crevice corrosion. Ti has a pitting potential greater than 3 V. Comparison between the in vitro measurements of the corrosion rate of nickel-based alloys and the clinical observation of the occurrence of contact dermatitis is discussed.

  18. Gold-nickel-titanium brazing alloy

    Science.gov (United States)

    Mizuhara, Howard

    1990-07-03

    A brazing alloy in accordance with this invention has the following composition, by weight: 91 to 99% gold, 0.5 to 7% nickel; 0.10 to 2% titanium. Alternatively, with palladium present, the composition is as follows, by weight: 83 to 96% gold; 3 to 10% palladium; 0.5 to 5% nickel; 0.10 to 2% titanium.

  19. Biocompatibility of nickel and cobalt dental alloys.

    Science.gov (United States)

    Grimaudo, N J

    2001-01-01

    Allergies related to dentistry generally constitute delayed hypersensitivity reactions to specific dental materials. Although true allergic hypersensitivity to dental materials is rare, certain products have definite allergenic properties. This review presents a comparative evaluation of the biocompatibility of nickel-chromium, nickel-chromium-beryllium, and cobalt-chromium alloys.

  20. Replicated Electro-Formed Nickel Alloy Mirror

    Science.gov (United States)

    1999-01-01

    NASA's Space Optics Manufacturing Center has been working to expand our view of the universe via sophisticated new telescopes. The Optics Center's goal is to develop low-cost, advanced space optics technologies for the NASA program in the 21st century - including the long-term goal of imaging Earth-like planets in distant solar systems. To reduce the cost of mirror fabrication, Marshall Space Flight Center (MSFC) has developed replication techniques, the machinery, and materials to replicate electro-formed nickel mirrors. The process allows fabricating precisely shaped mandrels to be used and reused as masters for replicating high-quality mirrors. Dr. Joe Ritter examines a replicated electro-formed nickel-alloy mirror which exemplifies the improvements in mirror fabrication techniques, with benefits such as dramtic weight reduction that have been achieved at the Marshall Space Flight Center's Space Optics Manufacturing Technology Center (SOMTC).

  1. High strength alloys

    Energy Technology Data Exchange (ETDEWEB)

    Maziasz, Phillip James; Shingledecker, John Paul; Santella, Michael Leonard; Schneibel, Joachim Hugo; Sikka, Vinod Kumar; Vinegar, Harold J.; John, Randy Carl; Kim, Dong Sub

    2012-06-05

    High strength metal alloys are described herein. At least one composition of a metal alloy includes chromium, nickel, copper, manganese, silicon, niobium, tungsten and iron. System, methods, and heaters that include the high strength metal alloys are described herein. At least one heater system may include a canister at least partially made from material containing at least one of the metal alloys. At least one system for heating a subterranean formation may include a tublar that is at least partially made from a material containing at least one of the metal alloys.

  2. High strength alloys

    Energy Technology Data Exchange (ETDEWEB)

    Maziasz, Phillip James [Oak Ridge, TN; Shingledecker, John Paul [Knoxville, TN; Santella, Michael Leonard [Knoxville, TN; Schneibel, Joachim Hugo [Knoxville, TN; Sikka, Vinod Kumar [Oak Ridge, TN; Vinegar, Harold J [Bellaire, TX; John, Randy Carl [Houston, TX; Kim, Dong Sub [Sugar Land, TX

    2010-08-31

    High strength metal alloys are described herein. At least one composition of a metal alloy includes chromium, nickel, copper, manganese, silicon, niobium, tungsten and iron. System, methods, and heaters that include the high strength metal alloys are described herein. At least one heater system may include a canister at least partially made from material containing at least one of the metal alloys. At least one system for heating a subterranean formation may include a tubular that is at least partially made from a material containing at least one of the metal alloys.

  3. High temperature mechanical properties of a zirconium-modified, precipitation- strengthened nickel, 30 percent copper alloy

    Science.gov (United States)

    Whittenberger, J. D.

    1974-01-01

    A precipitation-strengthened Monel-type alloy has been developed through minor alloying additions of zirconium to a base Ni-30Cu alloy. The results of this exploratory study indicate that thermomechanical processing of a solution-treated Ni-30Cu-0.2Zr alloy produced a dispersion of precipitates. The precipitates have been tentatively identified as a Ni5Zr compound. A comparison of the mechanical properties, as determined by testing in air, of the zirconium-modified alloy to those of a Ni-30Cu alloy reveals that the precipitation-strengthened alloy has improved tensile properties to 1200 K and improved stress-rupture properties to 1100 K. The oxidation characteristics of the modified alloy appeared to be equivalent to those of the base Ni-30Cu alloy.

  4. Human biomonitoring of chromium and nickel from an experimental exposure to manual metal arc welding fumes of low and high alloyed steel.

    Science.gov (United States)

    Bertram, Jens; Brand, Peter; Schettgen, Thomas; Lenz, Klaus; Purrio, Ellwyn; Reisgen, Uwe; Kraus, Thomas

    2015-05-01

    The uptake and elimination of metals from welding fumes is currently not fully understood. In the Aachen Workplace Simulation Laboratory (AWSL) it is possible to investigate the impact of welding fumes on human subjects under controlled exposure conditions. In this study, the uptake and elimination of chromium or chromium (VI) respectively as well as nickel was studied in subjects after exposure to the emissions of a manual metal arc welding process using low or high alloyed steel. In this present study 12 healthy male non-smokers, who never worked as welders before, were exposed for 6h to welding fumes of a manual metal arc welding process. In a three-fold crossover study design, subjects were exposed in randomized order to either clean air, emissions from welding low alloyed steel, and emissions from welding high alloyed steel. Particle mass concentration of the exposure aerosol was 2.5mg m(-3). The content of chromium and nickel in the air was determined by analysing air filter samples on a high emission scenario. Urine analysis for chromium and nickel was performed before and after exposure using methods of human biomonitoring. There were significantly elevated chromium levels after exposure to welding fumes from high alloyed steel compared to urinary chromium levels before exposure to high alloyed welding fumes, as well as compared to the other exposure scenarios. The mean values increased from 0.27 µg l(-1) to 18.62 µg l(-1). The results were in good agreement with already existing correlations between external and internal exposure (German exposure equivalent for carcinogenic working materials EKA). The variability of urinary chromium levels was high. For urinary nickel no significant changes could be detected at all. Six-hour exposure to 2.5mg m(-3) high alloyed manual metal arc welding fumes lead to elevated urinary chromium levels far higher (7.11-34.16 µg l(-1)) than the German biological exposure reference value (BAR) of 0.6 µg l(-1) directly after

  5. Nickel/metal hydride batteries using rate-earth hydrogen storage alloy

    Science.gov (United States)

    Chen, J.; Zhang, Y. S.

    1994-07-01

    Fine particles of a hydrogen storage alloy (LaNi3.8Co0.5Mn0.4Al0.3) were microencapsulated with a thin film of nickel of about 0.6 micron thickness. The microencapsulated alloy powders were used as an anode material in a sealed nickel/metal hydride battery. The battery characteristics were compared with those of a battery with a bare (uncoated) alloy anode. The battery using the bare alloy was less stable compared to the coated alloy due to the role of the coated nickel as an oxygen barrier for protecting the alloy surface from oxidation. In addition, charge- discharge characteristics were improved greatly by the nickel coating, especially at high rates and at low temperatures due to the role of nickel as a microcurrent collector. So the microencapsulation of the alloy powders improves the performances of the alloy electrode.

  6. Nanophase Nickel-Zirconium Alloys for Fuel Cells

    Science.gov (United States)

    Narayanan, Sekharipuram; Whitacre, jay; Valdez, Thomas

    2008-01-01

    Nanophase nickel-zirconium alloys have been investigated for use as electrically conductive coatings and catalyst supports in fuel cells. Heretofore, noble metals have been used because they resist corrosion in the harsh, acidic fuel cell interior environments. However, the high cost of noble metals has prompted a search for less-costly substitutes. Nickel-zirconium alloys belong to a class of base metal alloys formed from transition elements of widely different d-electron configurations. These alloys generally exhibit unique physical, chemical, and metallurgical properties that can include corrosion resistance. Inasmuch as corrosion is accelerated by free-energy differences between bulk material and grain boundaries, it was conjectured that amorphous (glassy) and nanophase forms of these alloys could offer the desired corrosion resistance. For experiments to test the conjecture, thin alloy films containing various proportions of nickel and zirconium were deposited by magnetron and radiofrequency co-sputtering of nickel and zirconium. The results of x-ray diffraction studies of the deposited films suggested that the films had a nanophase and nearly amorphous character.

  7. Structure and phases in nickel-base self-fluxing alloy coating containing high chromium and boron

    Science.gov (United States)

    Otsubo, F.; Era, H.; Kishitake, K.

    2000-03-01

    The structure of a nickel-base, self-fluxing alloy coating, containing chromium and boron thermal sprayed and fused, was investigated by x-ray diffraction (XRD), scanning electron microscopy (SEM), electron probe microanalysis (EPMA), and transmission electron microscopy (TEM). A lumpy M6C carbide, a rodlike M3B2 boride of tetragonal structure, a rodlike M7C3 carbide of hexagonal structure, and a Ni-Ni3B eutectic phase formed in the coating after fusing. Metals of M6C, M3B2, and M7C3 phases are composed of chromium, molybdenum, and nickel; chromium and molybdenum; and mainly chromium, respectively. The nickel phase in the coating has the L12 type superlattice structure.

  8. Influence of High-Current-Density Impulses on the Compression Behavior: Experiments with Iron and a Nickel-Based Alloy

    Science.gov (United States)

    Demler, E.; Gerstein, G.; Dalinger, A.; Epishin, A.; Rodman, D.; Nürnberger, F.

    2017-01-01

    Difficulties of processing of high strength and/or brittle materials by plastic deformation, e.g., by forging, require to develop new industrial technologies. In particular, the feasible deformation rates are limited for low-ductile metallic materials. For this reason, processes were investigated to improve the deformability in which electrical impulses are to be applied to lower the yield strength. However, owing to the impulse duration and low current densities, concomitant effects always occur, e.g., as a result of Joule heating. Current developments in power electronics allow now to transmit high currents as short pulses. By reducing the impulse duration and increasing the current density, the plasticity of metallic materials can be correspondingly increased. Using the examples of polycrystalline iron and a single-crystal, nickel-based alloy (PWA 1480), current advances in the development of methods for forming materials by means of high-current-density impulses are demonstrated. For this purpose, appropriate specimens were loaded in compression and, using novel testing equipment, subjected to a current strength of 10 kA with an impulse duration of 2 ms. For a pre-defined strain, the test results show a significant decrease in the compressive stress during the compression test and a significant change in the dislocation distribution following the current impulse treatment.

  9. Nickel alloys development-Inconel alloys development

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yong Soo; Uhm, Tae Sik; Kim, Taek Jun; Jeon, Yu Taek; Chang, Hyun Young [Yonsei University, Seoul (Korea, Republic of); Kim, Young Sik [Andong National University, Andon (Korea, Republic of)

    1996-07-01

    This report dealt with the evaluation of Alloy 600 and alloy 690 of steam= generator materials. The experimental alloys were divided into two groups. ; Seamless tubings made by different ingot, and Mo-modified alloys. Thermal treatment had no influenced on the anodic polarization resistance in some caustic solution, but improved stress corrosion resistance by CERT. The effect of SO{sub 4}{sup =} ions reduced markedly caustic SCC resistance. The corrosion mode by 70 days and 120 days C-ring tests revealed the intergranular corrosion instead of stress corrosion cracking. Mo addition on the corrosion resistance of Alloy 690M showed beneficial effect in neutral and acidic solutions, but a little effect in caustic solutions. However, the caustic stress corrosion resistance was improved by the addition of molybdenum. 27 refs., 84 figs., 5 tabs. (author)

  10. Analysis of thermoelectric properties of high-temperature complex alloys of nickel-base, iron-base and cobalt-base groups

    Science.gov (United States)

    Holanda, R.

    1984-01-01

    The thermoelectric properties alloys of the nickel-base, iron-base, and cobalt-base groups containing from 1% to 25% 106 chromium were compared and correlated with the following material characteristics: atomic percent of the principle alloy constituent; ratio of concentration of two constituents; alloy physical property (electrical resistivity); alloy phase structure (percent precipitate or percent hardener content); alloy electronic structure (electron concentration). For solid-solution-type alloys the most consistent correlation was obtained with electron concentration, for precipitation-hardenable alloys of the nickel-base superalloy group, the thermoelectric potential correlated with hardener content in the alloy structure. For solid-solution-type alloys, no problems were found with thermoelectric stability to 1000; for precipitation-hardenable alloys, thermoelectric stability was dependent on phase stability. The effects of the compositional range of alloy constituents on temperature measurement uncertainty are discussed.

  11. Effect of aluminumion implantation on high temperature oxidation of nickel-based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Mitsuo, Atsushi (Tokyo Metropolitan Industrial Technology Center, 3-13-10 Nishigaoka, Kita-ku, Tokyo 115 (Japan)); Tanaki, Toshiyuki (Tokyo Metropolitan Industrial Technology Center, 3-13-10 Nishigaoka, Kita-ku, Tokyo 115 (Japan)); Shinozaki, Teruo (Japan Gas Appliances Inspection Association, 4-1-10 Azusawa, Itabashi-ku, Tokyo 174 (Japan)); Iwaki, Masaya (Institute of Physics and Chemical Research, 2-1 Hirosawa, Wako-shi, Saitama 350-01 (Japan))

    1994-08-01

    The thermal oxidation properties of Al-ion-implanted, Ni-based alloys used for thermocouples of Inconel 600, alumel, chromel and constantan have been studied in humid O[sub 2] atmospheres at 970K for 50h. The Al ion implantation was performed with doses ranging from 1x10[sup 16] to 2x10[sup 17] ioncm[sup -2] at an energy of 50keV. The depth profiles measured by Auger electron spectroscopy showed that the concentrations of Al and O were higher near the surface of the alloys after implantation. The implanted alumel and constantan exhibited no effect on the suppression of oxidation. However, implantation above a dose of 1x10[sup 17]Al ioncm[sup -2] significantly slowed the oxidation of the Inconel 600 and chromel alloys containing Cr. The thermoelectric properties of the actual thermocouples modified by Al ion implantation are discussed. ((orig.))

  12. Structure and properties of deformable nickel alloys for gas turbines

    Science.gov (United States)

    Filatova, M. A.; Sudakov, V. S.

    1994-12-01

    The construction of high power gas turbine installations necessitates the development and use of new high-strength heat-resistant nickel alloys for large forged turbine blades. The blade material must possess not only superior properties (high temperature strength, ductility, fatigue and thermal fatigue strength, stability in the fuel combustion products) but also the required level of metallurgical and manufacturing producibility. The results of a study of the deformable nickel alloys KhN65KVMYuTB (ÉK78), KhN65KMVYuB (ÉP800), and KhN60KVYuMB (ÉP957), which have substantially better properties than the alloy now used for gas turbine blades (KhN65VMTYu) (ÉI893), are presented in this article.

  13. Process for the electrodeposition of low stress nickel-manganese alloys

    Science.gov (United States)

    Kelly, James John; Goods, Steven Howard; Yang, Nancy Yuan-Chi; Cadden, Charles Henry

    2005-06-07

    A process for electrodepositing a low stress nickel-manganese multilayer alloy on an electrically conductive substrate is provided. The process includes the steps of immersing the substrate in an electrodeposition solution containing a nickel salt and a manganese salt and repeatedly passing an electric current through an immersed surface of the substrate. The electric current is alternately pulsed for predetermined durations between a first electrical current that is effective to electrodeposit nickel and a second electrical current that is effective to electrodeposit nickel and manganese. A multilayered alloy having adjacent layers of nickel and a nickel-manganese alloy on the immersed surface of the substrate is thereby produced. The resulting multilayered alloy exhibits low internal stress, high strength and ductility, and high strength retention upon exposure to heat.

  14. High temperature deformation behavior and processing map for a nickel-titanium shape memory alloy

    Science.gov (United States)

    Yin, Xiang-Qian; Lee, Sang-Won; Li, Yan-Feng; Park, Chan-Hee; Mi, Xu-Jun; Yeom, Jong-Taek

    2017-09-01

    The hot deformation behavior of 49.2Ti-50.8Ni shape memory alloy was studied using hot compressive deformation testing in the temperature range of 1023-1323 K and at strain rates of 0.01-10 s-1. The work-hardening rate was induced to analyze the stress-strain curves, and the critical stress σc and the dynamic recovery saturation stress σsat were measured which can be specified approximately by the expressions: σsat-1.12σp and σc-0.86σp. An Arrhenius model was calculated to describe the relationship between peak stress and the Z parameter. The relationship between deformation activation energy, the deformation conditions and the effect of Ni component in a binary TiNi alloy on the activation energy were discussed in this work. With the help of electron backscattering diffraction, a connected mode dynamic recrystallization microstructure was confirmed in peak efficiency regimes (850 °C & 0.01 s-1 and 1050 °C & 10 s-1) of the processing map.

  15. Nickel-titanium alloys: a systematic review

    Directory of Open Access Journals (Sweden)

    Marcelo do Amaral Ferreira

    2012-06-01

    Full Text Available OBJECTIVE: A systematic review on nickel-titanium wires was performed. The strategy was focused on Entrez-PubMed-OLDMEDLINE, Scopus and BioMed Central from 1963 to 2008. METHODS: Papers in English and French describing the behavior of these wires and laboratorial methods to identify crystalline transformation were considered. A total of 29 papers were selected. RESULTS: Nickel-titanium wires show exceptional features in terms of elasticity and shape memory effects. However, clinical applications request a deeper knowledge of these properties in order to allow the professional to use them in a rational manner. In addition, the necessary information regarding each alloy often does not correspond to the information given by the manufacturer. Many alloys called "superelastic" do not present this effect; they just behave as less stiff alloys, with a larger springback if compared to the stainless steel wires. CONCLUSIONS: Laboratory tests are the only means to observe the real behavior of these materials, including temperature transition range (TTR and applied tensions. However, it is also possible to determine in which TTR these alloys change the crystalline structure.

  16. Arrhenius-Type Constitutive Model for High Temperature Flow Stress in a Nickel-Based Corrosion-Resistant Alloy

    Science.gov (United States)

    Wang, L.; Liu, F.; Cheng, J. J.; Zuo, Q.; Chen, C. F.

    2016-04-01

    Hot deformation behavior of Nickel-based corrosion-resistant alloy (N08028) was studied in compression tests conducted in the temperature range of 1050-1200 °C and the strain rate range of 0.001-1 s-1. The flow stress behavior and microstructural evolution were observed during the hot deformation process. The results show that the flow stress increases with deformation temperature decreasing and strain rate increasing, and that the deformation activation energy ( Q) is not a constant but increases with strain rate increasing at a given strain, which is closely related with dislocation movement. On this basis, a revised strain-dependent hyperbolic sine constitutive model was established, which considered that the "material constants" in the original model vary as functions of the strain and strain rate. The flow curves of N08028 alloy predicted by the proposed model are in good agreement with the experimental results, which indicates that the revised constitutive model can estimate precisely the flow curves of N08028 alloy.

  17. Effective and Environmentally Friendly Nickel Coating on the Magnesium Alloy

    Directory of Open Access Journals (Sweden)

    Ivana Škugor Rončević

    2016-12-01

    Full Text Available The low density and good mechanical properties make magnesium and its alloys attractive construction materials in the electronics, automotive, and aerospace industry, together with application in medicine due to their biocompatibility. Magnesium AZ91D alloy is an alloy with a high content of aluminum, whose mechanical properties overshadow the low corrosion resistance caused by the composition of the alloy and the existence of two phases: α magnesium matrix and β magnesium aluminum intermetallic compound. To improve the corrosion resistance, it is necessary to find an effective protection method for the alloy surface. Knowing and predicting electrochemical processes is an essential for the design and optimization of protective coatings on magnesium and its alloys. In this work, the formations of nickel protective coatings on the magnesium AZ91D alloy surface by electrodeposition and chemical deposition, are presented. For this purpose, environmentally friendly electrolytes were used. The corrosion resistance of the protected alloy was determined in chloride medium using appropriate electrochemical techniques. Characterization of the surface was performed with highly sophisticated surface-analytical methods.

  18. Arc fusion of self-fluxed nickel alloys

    OpenAIRE

    Marques,Paulo Villani; Trevisan,Roseana da Exaltação

    2000-01-01

    Self-fluxed nickel alloys are usually flame fused after thermal spraying. However, due to the practical aspects of high temperatures reached during flame fusing, large structures such as the hydraulic turbines for power generation, can not be efficiently coated. An alternative is to fuse the sprayed coating with a gas tungsten electric arc. In this case, heating is much more intensive and substrate temperature during and after the fusing operation is much lower, thus reducing the possibility ...

  19. Cobalt, nickel and chromium release from dental tools and alloys.

    Science.gov (United States)

    Kettelarij, Jolinde A B; Lidén, Carola; Axén, Emmy; Julander, Anneli

    2014-01-01

    Cobalt-chromium alloys are used as casting alloys by dental technicians when producing dental prostheses and implants. Skin exposure and metal release from alloys and tools used by the dental technicians have not been studied previously. To study the release of cobalt, nickel and chromium from alloys and tools that come into contact with the skin of dental technicians. Cobalt and nickel release from tools and alloys was tested with the cobalt spot test and the dimethylglyoxime test for nickel. Also, the release of cobalt, nickel and chromium in artificial sweat (EN1811) at different time-points was assessed. Analysis was performed with inductively coupled plasma-mass spectrometry. Sixty-one tools were spot tested; 20% released nickel and 23% released cobalt. Twenty-one tools and five dental alloys were immersed in artificial sweat. All tools released cobalt, nickel and chromium. The ranges were 0.0047-820, 0.0051-10 and 0.010-160 µg/cm(2) /week for cobalt, nickel and chromium, respectively. All dental alloys released cobalt in artificial sweat, with a range of 0.0010-17 µg/cm(2) /week, and they also released nickel and chromium at low concentrations. Sensitizing metals are released from tools and alloys used by dental technicians. This may cause contact allergy and hand eczema. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. Thermophysical properties of Incoloy 800 and five additional FeNiCr-base high temperature alloys in comparison with the nickel-base alloy Nimonic 86 between 20 and 1000deg C

    Energy Technology Data Exchange (ETDEWEB)

    Richter, F. (Mannesmann-Forschungsinstitut GmbH, Duisburg (Germany, F.R.))

    1991-05-01

    The most important physical properties of the following high temperature alloys have been determined in the temperature range between 20 and 1000deg C: Incoloy 800, Incoloy 800 H, Incoloy 802, Incoloy 802 Nb, Manaurite 36 X, IN 519 and Nimonic 86. It is shown that these materials differ only a little in some of the properties. These properties include thermal expansion, thermal conductivity and thermal diffusivity. Owing to a substantially higher nickel content, the density of the nickel-base alloy Nimonic 86 differs significantly from that of the other materials investigated. The differences in the elastic properties of the materials are to be attributed to the differences in their crystallographic texture. Incoly 800 was very highly textured compared to other materials. The temperature dependence of the coefficient of linear thermal expansion and electrical resistivity of these materials is different from the normal behaviour of pure metals and alloys. The discrepancies observed are attributable to short range ordering processes in the case of Nimonic 86 and to temperature-induced electron transitons in the case of the other materials investigated, as known for austenitic Cr-Ni steels. (orig.).

  1. Transient liquid phase bonding of magnesium alloys AZ31 using nickel coatings and high frequency induction heat sintering

    Directory of Open Access Journals (Sweden)

    A.N. AlHazaa

    2016-04-01

    Full Text Available Transient liquid phase (TLP bonding process was applied to join magnesium alloy AZ31 samples with minimum microstructural changes. The magnesium samples were coated by 5 μm nickel prior to the TLP bonding. Bonding conditions of 8 MPa uniaxial pressure and 520 °C bonding temperature were applied for all bonds at various bonding times. The microstructure across the joint regions was examined as a function of bonding time (5–60 min. Investigating the change in Ni contents was examined by EDS line scan. It was noticed that Ni coating could not be observed by SEM for bonds made at 30 and 60 min due to complete dissolution of the Ni coating. Second phase particles containing Mg2Ni intermetallics were observed by X-ray Photoelectron Spectroscopy (XPS near the joint region. The shear strength of the bonds initially increases with the increase in bonding time till 20 min. On the other hand, with bonding times over 20 min the shear strength decreases. Therefore the optimum bonding time at the conditions applied was concluded to be 20 min.

  2. Evaluation of flexural bond strength of porcelain to used nickel-chromium alloy in various percentages

    Directory of Open Access Journals (Sweden)

    VNV Madhav

    2012-01-01

    Fresh nickel-chromium alloy shows the greatest porcelain adherence.There is no significant change in bond strength of ceramic to alloy with up to 75% of used nickel-chromium alloy.At least 25%- of new alloy should be added when recycled nickel-chromium alloy is being used for metal ceramic restorations.

  3. Computer simulations of martensitic transformations in iron-nickel and nickel-aluminium alloys

    CERN Document Server

    Meyer, R J

    1998-01-01

    This thesis focuses on the martensitic transformations in iron-nickel and nickel-aluminum alloys. Molecular-dynamics simulations have been done, employing potentials based on the so-called embedded-atom method (EAM). These potentials were obtained by a fit of parameterized functions to experimental data of the elements iron, nickel, and aluminum as well as the intermetallic compound NiAl. Many aspects of the austenitic transformation in iron-nickel alloys and both, the martensitic and austenitic transformations, in nickel-aluminum alloys were reproduced well by the simulations. The results allow to draw conclusions on the reasons of differences and similarities in the behavior of both alloy systems.

  4. Peculiar features of boron distribution in high temperature fracture area of rapidly quenched heat-resistant nickel alloy

    Energy Technology Data Exchange (ETDEWEB)

    Shulga, A. V., E-mail: avshulga@mephi.ru [National Research Nuclear University MEPhI (Russian Federation)

    2016-12-15

    This article comprises the results of comprehensive study of the structure and distribution in the high temperature fracture area of rapidly quenched heat-resistant superalloy of grade EP741NP after tensile tests. The structure and boron distribution in the fracture area are studied in detail by means of direct track autoradiography in combination with metallography of macro- and microstructure. A rather extensive region of microcracks generation and intensive boron redistribution is detected in the high temperature fracture area of rapidly quenched nickel superalloy of grade EP741NP. A significant decrease in boron content in the fracture area and formation of elliptically arranged boride precipitates are revealed. The mechanism of intense boron migration and stability violation of the structural and phase state in the fracture area of rapidly quenched heat-resistant nickel superalloy of grade EP741NP is proposed on the basis of accounting for deformation occurring in the fracture area and analysis of the stressed state near a crack.

  5. Hydrogen adsorption and diffusion, and subcritical-crack growth in high strength steels and nickel base alloys

    Science.gov (United States)

    Wei, R. P.; Klier, K.; Simmons, G. W.; Chornet, E.

    1973-01-01

    Embrittlement, or the enhancement of crack growth by gaseous hydrogen in high strength alloys, is of primary interest in selecting alloys for various components in the space shuttle. Embrittlement is known to occur at hydrogen gas pressures ranging from fractions to several hundred atmospheres, and is most severe in the case of martensitic high strength steels. Kinetic information on subcritical crack growth in gaseous hydrogen is sparse at this time. Corroborative information on hydrogen adsorption and diffusion is inadequate to permit a clear determination of the rate controlling process and possible mechanism in hydrogen enhanced crack growth, and for estimating behavior over a range of temperatures and pressures. Therefore, coordinated studies of the kinetics of crack growth, and adsorption and diffusion of hydrogen, using identical materials, have been initiated. Comparable conditions of temperature and pressure will be used in the chemical and mechanical experiments. Inconel 718 alloy and 18Ni(200) maraging steel have been selected for these studies. Results from these studies are expected to provide not only a better understanding of the gaseous hydrogen embrittlement phenomenon itself, but also fundamental information on hydrogen adsorption and diffusion, and crack growth information that can be used directly for design.

  6. Advanced characterization techniques in understanding the roles of nickel in enhancing strength and toughness of submerged arc welding high strength low alloy steel multiple pass welds in the as-welded condition

    Science.gov (United States)

    Sham, Kin-Ling

    Striving for higher strength along with higher toughness is a constant goal in material properties. Even though nickel is known as an effective alloying element in improving the resistance of a steel to impact fracture, it is not fully understood how nickel enhances toughness. It was the goal of this work to assist and further the understanding of how nickel enhanced toughness and maintained strength in particular for high strength low alloy (HSLA) steel submerged arc welding multiple pass welds in the as-welded condition. Using advanced analytical techniques such as electron backscatter diffraction, x-ray diffraction, electron microprobe, differential scanning calorimetry, and thermodynamic modeling software, the effect of nickel was studied with nickel varying from one to five wt. pct. in increments of one wt. pct. in a specific HSLA steel submerged arc welding multiple pass weldment. The test matrix of five different nickel compositions in the as-welded and stress-relieved condition was to meet the targeted mechanical properties with a yield strength greater than or equal to 85 ksi, a ultimate tensile strength greater than or equal to 105 ksi, and a nil ductility temperature less than or equal to -140 degrees F. Mechanical testing demonstrated that nickel content of three wt. pct and greater in the as-welded condition fulfilled the targeted mechanical properties. Therefore, one, three, and five wt. pct. nickel in the as-welded condition was further studied to determine the effect of nickel on primary solidification mode, nickel solute segregation, dendrite thickness, phase transformation temperatures, effective ferrite grain size, dislocation density and strain, grain misorientation distribution, and precipitates. From one to five wt. pct nickel content in the as-welded condition, the primary solidification was shown to change from primary delta-ferrite to primary austenite. The nickel partitioning coefficient increased and dendrite/cellular thickness was

  7. Generalized corrosion of nickel base alloys in high temperature aqueous media: a contribution to the comprehension of the mechanisms; Corrosion generalisee des alliages a base nickel en milieu aqueux a haute temperature: apport a la comprehension des mecanismes

    Energy Technology Data Exchange (ETDEWEB)

    Marchetti-Sillans, L

    2007-11-15

    In France, nickel base alloys, such as alloy 600 and alloy 690, are the materials constituting steam generators (SG) tubes of pressurized water reactors (PWR). The generalized corrosion resulting from the interaction between these alloys and the PWR primary media leads, on the one hand, to the formation of a thin protective oxide scale ({approx} 10 nm), and on the other hand, to the release of cations in the primary circuit, which entails an increase of the global radioactivity of this circuit. The goal of this work is to supply some new comprehension elements about nickel base alloys corrosion phenomena in PWR primary media, taking up with underlining the effects of metallurgical and physico-chemical parameters on the nature and the growth mechanisms of the protective oxide scale. In this context, the passive film formed during the exposition of alloys 600, 690 and Ni-30Cr, in conditions simulating the PWR primary media, has been analyzed by a set of characterization techniques (SEM, TEM, PEC and MPEC, XPS). The coupling of these methods leads to a fine description, in terms of nature and structure, of the multilayered oxide forming during the exposition of nickel base alloys in primary media. Thus, the protective part of the oxide scale is composed of a continuous layer of iron and nickel mixed chromite, and Cr{sub 2}O{sub 3} nodules dispersed at the alloy / mixed chromite interface. The study of protective scale growth mechanisms by tracers and markers experiments reveals that the formation of the mixed chromite is the consequence of an anionic mechanism, resulting from short circuits like grain boundaries diffusion. Besides, the impact of alloy surface defects has also been studied, underlining a double effect of this parameter, which influences the short circuits diffusion density in oxide and the formation rate of Cr{sub 2}O{sub 3} nodules. The sum of these results leads to suggest a description of the nickel base alloys corrosion mechanisms in PWR primary

  8. Nickel-Titanium Alloys: Corrosion "Proof" Alloys for Space Bearing, Components and Mechanism Applications

    Science.gov (United States)

    DellaCorte, Christopher

    2010-01-01

    An intermetallic nickel-titanium alloy, 60NiTi (60 wt% Ni, 40 wt% Ti), is shown to be a promising candidate tribological material for space mechanisms. 60NiTi offers a broad combination of physical properties that make it unique among bearing materials. 60NiTi is hard, electrically conductive, highly corrosion resistant, readily machined prior to final heat treatment, and is non-magnetic. Despite its high Ti content, 60NiTi is non-galling even under dry sliding. No other bearing alloy, metallic or ceramic, encompasses all of these attributes. Since 60NiTi contains such a high proportion of Ti and possesses many metallic properties, it was expected to exhibit poor tribological performance typical of Ti alloys, namely galling type behavior and rapid lubricant degradation. In this poster-paper, the oil-lubricated behavior of 60NiTi is presented.

  9. Characterization of zinc–nickel alloy electrodeposits obtained from ...

    Indian Academy of Sciences (India)

    Zinc alloy offers superior sacrificial protection to steel as the alloy dissolves more slowly than pure zinc. ... characterization of zinc-nickel electrodeposits obtained from sulphamate bath containing substituted aldehydes was carried out using hardness testing, X-ray diffraction, and corrosion resistance measurements.

  10. Electrochemical and surface characterization of a nickel-titanium alloy

    NARCIS (Netherlands)

    Wever, Dirk; Veldhuizen, AG; de Vries, J; Busscher, HJ; Uges, DRA; van Horn, James

    1998-01-01

    For clinical implantation purposes of shape memory metals the nearly equiatomic nickel-titanium (NiTi) alloy is generally used. In this study, the corrosion properties and surface characteristics of this alloy were investigated and compared with two reference controls, AISI 316 LVM stainless steel

  11. PLUTONIUM-CERIUM-COBALT AND PLUTONIUM-CERIUM-NICKEL ALLOYS

    Science.gov (United States)

    Coffinberry, A.S.

    1959-08-25

    >New plutonium-base teroary alloys useful as liquid reactor fuels are described. The alloys consist of 10 to 20 atomic percent cobalt with the remainder plutonium and cerium in any desired proportion, with the plutonium not in excess of 88 atomic percent; or, of from 10 to 25 atomic percent nickel (or mixture of nickel and cobalt) with the remainder plutonium and cerium in any desired proportion, with the plutonium not in excess of 86 atomic percent. The stated advantages of these alloys over unalloyed plutonium for reactor fuel use are a lower melting point and a wide range of permissible plutonium dilution.

  12. Production of high-purity nickel base alloys by electroslag remelting; Hochreine Nickelbasislegierungen durch Elektro-Schlacke-Umschmelzverfahren

    Energy Technology Data Exchange (ETDEWEB)

    Schmilinsky, E. [Krupp VDM GmbH, Unna (Germany). Umschmelzbetrieb; Scholz, H. [ALD Vacuum Technologies GmbH, Erlensee (Germany)

    2000-12-01

    Electroslag melting is a process for production of high-density, low-fault blocks of high-purity special alloys ready for hot forming. A new melting unit is currently being constructed at the Unna plant of Krupp VDM GmbH. The whole melting process takes place in an adjustable inert gas atmosphere and is fully automatic. Refined alloys are used in applications where high corrosion resistance or high temperature resistance are required, e.g. in gas turbines, motor valves, offshore plants and the electronic industry. [German] Das Elektro-Schlacke-Umschmelzen (ESU) ermoeglicht die Erzeugung dichter, seigerungsarmer Bloecke von hochreinen Speziallegierungen, die auf Grund ihrer glatten und fehlerfreien Oberflaeche direkt durch Warmumformung weiterverarbeitet werden koennen. Am Standort Unna der Krupp VDM GmbH wird derzeit eine neue Umschmelzanlage in Betrieb genommen. Eine Besonderheit dieser Anlage ist ein gasdichter und evakuierbarer Ofenkessel fuer Rundformate, bei dem der gesamte Umschmelzprozess, der bei konventionellen ESU-Anlagen unter Luftatmosphaere stattfindet, unter einer gezielt einstellbaren Schutzgasatmosphaere ablaeuft. Eine ESU-Charge, die je nach Blockgewicht und -format bis zu 24 Stunden dauern kann, gliedert sich in Start-, Hauptschmelz- und Schopfheizphase auf. Die einzelnen Phasen laufen bei der VDM-Anlage nach Eingabe des Startdialogs, von einem Anlagen-Rechner gesteuert, vollautomatisch ab. Das Ergebnis des ESU-Prozesses ist ein Block mit isotropen Eigenschaften, hoher Dichte und Homogenitaet, ohne Seigerungen und Lunker. Umgeschmolzene Legierungen werden ueberall dort eingesetzt, wo ein Hoechstmass an Bestaendigkeit gegen korrosive Einwirkung oder hohe Temperaturen gefordert wird, wie z.B. bei Gasturbinen, Motorventilen, im Offshore-Bereich und in der Elektronikindustrie. (orig.)

  13. XPS and STM study of the growth and structure of passive films in high temperature water on a nickel-base alloy

    Energy Technology Data Exchange (ETDEWEB)

    Machet, A.; Galtayries, A.; Zanna, S.; Klein, L.; Maurice, V.; Jolivet, P.; Foucault, M.; Combrade, P.; Scott, P.; Marcus, P

    2004-09-15

    The early stages of passivation in high temperature water of a nickel-chromium-iron alloy (Alloy 600) have been investigated by X-ray Photoelectron Spectroscopy (XPS) and Scanning Tunneling Microscopy (STM). The samples (polycrystal Ni-16Cr-9Fe (wt. %) and single crystal Ni-17Cr-7Fe (1 1 1)) have been exposed for short time periods (0.4-8.2 min) to high temperature (325 deg. C) and high pressure water, under controlled hydrogen pressure, in a microautoclave designed to transfer the samples from and to the XPS spectrometer without air exposure. In the early stages of oxidation of the alloy (0.4-4 min), an ultra-thin oxide layer (about 1 nm) is formed, which consists of chromium oxide (Cr{sub 2}O{sub 3}), according to the Cr 2p{sub 3/2} core level spectrum. An outer layer of Cr(OH){sub 3} with a very small amount of Ni(OH){sub 2} is also revealed by the Cr 2p{sub 3/2}, Ni 2p{sub 3/2}, and O 1s core level spectra. At this early stage, there is a temporary blocking of the growth of Cr{sub 2}O{sub 3}. For longer exposures (4-8 min), the Cr{sub 2}O{sub 3} inner layer becomes thicker, at the expense of the outer Cr(OH){sub 3} layer. This implies the transport of Cr and Ni through the oxide layer, and release of Ni{sup 2+} in the solution. The structure of the ultra-thin oxide film formed on a single crystal Ni-17Cr-7Fe(1 1 1) alloy was analysed by STM in the constant current mode; STM images reveal that, in the early stages of oxidation, the oxide is crystalline, and the observed structure is consistent with the hexagonal structure of the oxygen sub-lattice in the basal plane (0 0 0 1) of {alpha}-Cr{sub 2}O{sub 3}.

  14. Brushing-induced surface roughness of nickel-, palladium-, and gold-based dental casting alloys.

    Science.gov (United States)

    Wataha, John C; Lockwood, Petra E; Messer, Regina L W; Lewis, Jill B; Mettenburg, Donald J

    2008-06-01

    Alloys with high nickel content have been increasingly used for dental prostheses. These alloys have excellent hardness, elastic modulus, and strength, yet have high corrosion rates when exposed to chemical or physical forces that are common intraorally. The purpose of the current study was to measure the susceptibility of several types of nickel-based alloys to brushing abrasion relative to gold- and palladium-based alloys. Au-Pt, Au-Pd, Pd-Ag, Ni-Cr, and Ni-Cr-Be dental alloys were brushed with a toothbrush (Oral-B Soft) and toothpaste (Ultrabrite) in a linear brushing machine, then the surface roughness was measured by profilometry (R(a), R(v), R(p)). Specimens (n=4) were brushed for 48 hours in a saline solution (pH 7). The effect of brushing was determined using 2-sided t tests (alpha=.05), and roughness among alloys postbrushing was compared using 1-way ANOVA with Tukey post hoc analyses (alpha=.05). All polished alloy surfaces (before brushing) had roughnesses of 1 microm (R(a)). Ni-Cr alloys without Be had a postbrushing surface roughness of 0.25 microm (R(a)). Postbrushing roughness of all other alloys ranged from 0.1-0.25 microm (R(a)). R(v) and R(p) values behaved similarly to R(a) values for all alloys. Although they have many excellent mechanical properties, Ni-Cr-Be alloys may be prone to degradation from brushing.

  15. The elemental move characteristic of nickel-based alloy in molten salt corrosion by using nuclear microprobe

    Science.gov (United States)

    Lei, Qiantao; Liu, Ke; Gao, Jie; Li, Xiaolin; Shen, Hao; Li, Yan

    2017-08-01

    Nickel-based alloys as candidate materials for Thorium Molten Salt Reactor (TMSR), need to be used under high temperature in molten salt environment. In order to ensure the safety of the reactor running, it is necessary to study the elemental move characteristic of nickel-based alloys in the high temperature molten salts. In this work, the scanning nuclear microprobe at Fudan University was applied to study the elemental move. The Nickel-based alloy samples were corroded by molten salt at different temperatures. The element concentrations in the Nickel-based alloys samples were determined by the scanning nuclear microprobe. Micro-PIXE results showed that the element concentrations changed from the interior to the exterior of the alloy samples after the corrosion.

  16. Hot corrosion of TD nickel and TD nickel chromium in a high velocity gas stream.

    Science.gov (United States)

    Sanders, W. A.; Probst, H. B.

    1971-01-01

    Results of cyclical tests of TD nickel (2% thoria-dispersed nickel) and TD nickel chromium (2% thoria-dispersed nickel-20% chromium alloy) 1.5 mm (60 mil) sheet specimens for susceptibility to hot corrosion in a Mach 0.5 gas stream of Jet A-1 fuel combustion products containing 2 ppm sea salt. Tests as long as 500 one-hour cycles between room temperature and specimen hot zone temperatures of 899 C (1650 F), 982 C (1800 F), and 1149 C (2100 F) were performed. Evidence of hot corrosion was found for both materials in the 899 C (1650 F) and 982 C (1800 F) tests, but not at 1149 C (2100 F). It was concluded that because of high metal thickness losses neither alloy in sheet form is suitable for long-time engine application in a hot corrosion environment at temperatures of 982 C (1800 F) or above.

  17. DEFORMATION TEXTURES IN A COPPER NICKEL ALLOY

    Directory of Open Access Journals (Sweden)

    Sacit DÜNDAR

    2002-03-01

    Full Text Available Non-random distribution of orientations between the neigbouring grains of polycrystalline aggregates leads to preferred orientations or textures. Texture analysis of a Cu-10 % Ni alloy carried out on three types of cast materials after varying amounts of deformation led to clearly defined copper type texture due to the dominance of high stacking fault energy SFE regions in the structure. (123 [41 2 ] is the strongest orientation observed with (123 as the plane lying paralel to the rolling plane and [41 2 ] as the direction paralel to the rolling direction.

  18. Regenerability of hydrotalcite-derived nickel-iron alloy nanoparticles for syngas production from biomass tar.

    Science.gov (United States)

    Li, Dalin; Koike, Mitsuru; Wang, Lei; Nakagawa, Yoshinao; Xu, Ya; Tomishige, Keiichi

    2014-02-01

    Nickel-iron/magnesium/aluminum bimetallic catalysts were prepared by the calcination and reduction of nickel-magnesium-iron-aluminum hydrotalcite-like compounds. Characterization suggests that, at iron/nickel≤0.5, both nickel and iron species are homogeneously distributed in the hydrotalcite precursor and incorporated into the Mg(Ni, Fe, Al)O periclase after calcination, giving rise to uniform nickel-iron alloy nanoparticles after reduction. Ni-Fe/Mg/Al (Fe/Ni=0.25) exhibits the best catalytic performance for the steam reforming of tar derived from the pyrolysis of biomass. It is suggested that the uniform nickel-iron alloy nanoparticles and the synergy between nickel and iron are responsible for the high catalytic performance. Moreover, the Ni-Fe/Mg/Al catalyst exhibits much better regenerability toward oxidation-reduction treatment for the removal of deposited coke than that of conventional Ni-Fe/α-Al2 O3 . This property can be attributed to the better regeneration of Ni-Fe alloy nanoparticles through the formation and reduction of Mg(Ni, Fe, Al)O. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Microfissuring in Electron-Beam-Welded Nickel Alloy

    Science.gov (United States)

    Nunes, A. C., Jr

    1985-01-01

    Mathematical model developed for microfissuring of commercial nickel alloy during electron-beam welding. Number of measured microfissures per unit length of weld plotted against excess power calculated by computer model. Excess power that above level likely to produce microfissures. In agreement with model, measured microfissures increase at rate of 4.5 per inch (1.8 per centimeter) per excess kilowatt.

  20. Determination of elastic modulus in nickel alloy from ultrasonic ...

    Indian Academy of Sciences (India)

    The aim of the present investigation is to study the behaviour of elastic constants and the variation on heat treatment in a nickel base super alloy Nimonic 263 by ultrasonic velocity measurements. From the present study it is evident that the elastic moduli of the material are very sensitive to any minor compositional changes, ...

  1. Thermodynamic Considerations of Contamination by Alloying Elements of Remelted End-of-Life Nickel- and Cobalt-Based Superalloys

    Science.gov (United States)

    Lu, Xin; Matsubae, Kazuyo; Nakajima, Kenichi; Nakamura, Shinichiro; Nagasaka, Tetsuya

    2016-06-01

    Cobalt and nickel are high-value commodity metals and are mostly used in the form of highly alloyed materials. The alloying elements used may cause contamination problems during recycling. To ensure maximum resource efficiency, an understanding of the removability of these alloying elements and the controllability of some of the primary alloying elements is essential with respect to the recycling of end-of-life (EoL) nickel- and cobalt-based superalloys by remelting. In this study, the distribution behaviors of approximately 30 elements that are usually present in EoL nickel- and cobalt-based superalloys in the solvent metal (nickel, cobalt, or nickel-cobalt alloy), oxide slag, and gas phases during the remelting were quantitatively evaluated using a thermodynamic approach. The results showed that most of the alloying elements can be removed either in the slag phase or into the gas phase. However, the removal of copper, tin, arsenic, and antimony by remelting is difficult, and they remain as tramp elements during the recycling. On the other hand, the distribution tendencies of iron, molybdenum, and tungsten can be controlled by changing the remelting conditions. To increase the resource efficiency of recycling, preventing contamination by the tramp elements and identifying the alloying compositions of EoL superalloys are significantly essential, which will require the development of efficient prior alloy-sorting systems and advanced separation technologies.

  2. Effect of alloying elements on the corrosion behaviour of copper-nickel alloys in a marine environment

    Science.gov (United States)

    Taher, Abulmaali M. Y.

    depends on maintaining iron in a single phase in the solid solution (the maximum amount of iron can be used was 1.5 w%). Quenching improves the electrochemical behaviour of synthetic Cu-Ni-Fe alloys containing relatively high iron content. The outer layer of the passive film is porous in the absence of iron, but when iron is added, the pores disappear and cracks appear. When no sulphate is present in the solution, the passive film formed on synthetic Cu-Ni-Fe alloys consists entirely of chlorides, and Fe2O3. In the presence of sulphate FeS and NiS where detected in the corrosion film. Cu-Ni-2.0 w% Co is the most protective alloy in both the 2260 ppm sulphate artificial saline solution and N.S. sea water, and it can replace the Cu-Ni-2.0 w% Fe [quenched] alloy in marine applications. The Cu-Ni-2 w% Al alloy is recommended to be used only in clean sea water (without sulphate content). It is not recommended to use Cu-Ni-2 w% Mo, Cu-Ni-2 w% In, Cu-Ni-2 w% V, or Cu-Ni-2 w% Ti alloys in all three environments. The behaviour of Cu-Ni-2 w% Cr alloy indicates that this alloy could be used to some extent. Addition of alloying elements to the copper-nickel alloys resulted in the presence of these elements in the passive film as oxides, and sometimes chlorides.

  3. Hydrogen adsorption and diffusion, and subcritical-crack growth in high-strength steels and nickel base alloys

    Science.gov (United States)

    Wei, R. P.; Klier, K.; Simmons, G. W.

    1974-01-01

    Coordinated studies of the kinetics of crack growth and of hydrogen adsorption and diffusion were initiated to develop information that is needed for a clearer determination of the rate controlling process and possible mechanism for hydrogen enhanced crack growth, and for estimating behavior over a range of temperatures and pressures. Inconel 718 alloy and 18Ni(200) maraging steel were selected for these studies. 18Ni(250) maraging steel, 316 stainless steel, and iron single crystal of (111) orientation were also included in the chemistry studies. Crack growth data on 18Ni(250) maraging steel from another program are included for comparison. No sustained-load crack growth was observed for the Inconel 718 alloy in gaseous hydrogen. Gaseous hydrogen assisted crack growth in the 18Ni maraging steels were characterized by K-independent (Stage 2) extension over a wide range of hydrogen pressures (86 to 2000 torr or 12 kN/m2 to 266 kN/m2) and test temperatures (-60 C to +100 C). The higher strength 18Ni(250) maraging steel was more susceptible than the lower strength 200 grade. A transition temperature was observed, above which crack growth rates became diminishingly small.

  4. DC Electric Arc Furnace Application for Production of Nickel-Boron Master Alloys

    Science.gov (United States)

    Alkan, Murat; Tasyürek, Kerem Can; Bugdayci, Mehmet; Turan, Ahmet; Yücel, Onuralp

    2017-09-01

    In this study, nickel-boron (Ni-B) alloys were produced via a carbothermic reduction starting from boric acid (H3BO3) with high-purity nickel oxide (NiO), charcoal, and wood chips in a direct current arc furnace. In electric arc furnace experiments, different starting mixtures were used, and their effects on the chemical compositions of the final Ni-B alloys were investigated. After the reduction and melting stages, Ni-B alloys were obtained by tapping from the bottom of the furnace. The samples from the designated areas were also taken and analyzed. The chemical composition of the final alloys and selected samples were measured with wet chemical analysis. The Ni-B alloys had a composition of up to 14.82 mass% B. The phase contents of the final alloys and selected samples were measured using x-ray diffraction (XRD). The XRD data helped predict possible reactions and reaction mechanisms. The material and energy balance calculations were made via the XRD Rietveld and chemical compositions. Nickel boride phases started to form 600 mm below the surface. The targeted NiB phase was detected at the tapping zone of the crucible (850-900 mm depth). The energy consumption was 1.84-4.29 kWh/kg, and the electrode consumption was 10-12 g/kg of raw material charged.

  5. Magnetic properties of the binary Nickel/Bismuth alloy

    Energy Technology Data Exchange (ETDEWEB)

    Keskin, Mustafa; Şarlı, Numan, E-mail: numansarli82@gmail.com

    2017-09-01

    Highlights: • We model and investigate the magnetic properties of the Ni/Bi alloy within the EFT. • Magnetizations of the Ni/Bi alloy are observed as Bi1 > Bi2 > Ni/Bi > Ni at T < Tc. • Magnetization of the Bi1 is dominant and Ni is at least dominant T < Tc. • Total magnetization of the Ni/Bi alloy is close to those of Ni at T < Tc. • Hysteresis curves are overlap at T < 0.1 and they behave separately at T > 0.1. - Abstract: Magnetic properties of the binary Nickel/Bismuth alloy (Ni/Bi) are investigated within the effective field theory. The Ni/Bi alloy has been modeled that the rhombohedral Bi lattice is surrounded by the hexagonal Ni lattice. According to lattice locations, Bi atoms have two different magnetic properties. Bi1 atoms are in the center of the hexagonal Ni atoms (Ni/Bi1 single layer) and Bi2 atoms are between two Ni/Bi1 bilayers. The Ni, Bi1, Bi2 and Ni/Bi undergo a second-order phase transition from the ferromagnetic phase to paramagnetic phase at Tc = 1.14. The magnetizations of the Ni/Bi alloy are observed as Bi1 > Bi2 > Ni/Bi > Ni at T < Tc; hence the magnetization of the Bi1 is dominant and Ni is at least dominant. However, the total magnetization of the Ni/Bi alloy is close to magnetization of the Ni at T < Tc. The corcivities of the Ni, Bi1, Bi2 and Ni/Bi alloy are the same with each others, but the remanence magnetizations are different. Our theoretical results of M(T) and M(H) of the Ni/Bi alloy are in quantitatively good agreement with the some experimental results of binary Nickel/Bismuth systems.

  6. Vapor phase lubrication of high temperature alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hanyaloglu, B.F.; Graham, E.E.; Oreskovic, T.; Hajj, C.G. [Cleveland State Univ., OH (United States)

    1995-06-01

    In a previous study, it was found that when a nickel-based superalloy IN750 was heated to high temperatures, a passive layer of aluminum oxide formed on the surface, preventing vapor phase lubrication. In this study, two nickel-chrome-iron alloys and a nickel-copper alloy were studied for high temperature lubrication to see if these alloys, which contained small amounts of aluminum, would exhibit similar behavior. It was found that under static conditions, all three alloys formed a lubricious nodular coating when exposed to a vapor of aryl phosphate. Under dynamic sliding conditions at 500{degrees}C, these alloys were successfully lubricated with a coefficient of friction of 0.1 and no detectable wear. In order to explain these results, a direct correlation between successful vapor phase lubrication and the composition of the alloys containing aluminum has been proposed. If the ratio of copper/aluminum or iron/aluminum is greater that 100 vapor phase, lubrication will be successful. If the ratio is less than 10, a passive aluminum oxide layer will prevent vapor phase lubrication. By selecting alloys with a high iron or copper content, vapor phase lubrication can provide excellent lubrication at high temperatures. 14 refs., 11 figs., 1 tab.

  7. Grinding temperature and energy ratio coefficient in MQL grinding of high-temperature nickel-base alloy by using different vegetable oils as base oil

    Directory of Open Access Journals (Sweden)

    Li Benkai

    2016-08-01

    Full Text Available Vegetable oil can be used as a base oil in minimal quantity of lubrication (MQL. This study compared the performances of MQL grinding by using castor oil, soybean oil, rapeseed oil, corn oil, sunflower oil, peanut oil, and palm oil as base oils. A K-P36 numerical-control precision surface grinder was used to perform plain grinding on a workpiece material with a high-temperature nickel base alloy. A YDM–III 99 three-dimensional dynamometer was used to measure grinding force, and a clip-type thermocouple was used to determine grinding temperature. The grinding force, grinding temperature, and energy ratio coefficient of MQL grinding were compared among the seven vegetable oil types. Results revealed that (1 castor oil-based MQL grinding yields the lowest grinding force but exhibits the highest grinding temperature and energy ratio coefficient; (2 palm oil-based MQL grinding generates the second lowest grinding force but shows the lowest grinding temperature and energy ratio coefficient; (3 MQL grinding based on the five other vegetable oils produces similar grinding forces, grinding temperatures, and energy ratio coefficients, with values ranging between those of castor oil and palm oil; (4 viscosity significantly influences grinding force and grinding temperature to a greater extent than fatty acid varieties and contents in vegetable oils; (5 although more viscous vegetable oil exhibits greater lubrication and significantly lower grinding force than less viscous vegetable oil, high viscosity reduces the heat exchange capability of vegetable oil and thus yields a high grinding temperature; (6 saturated fatty acid is a more efficient lubricant than unsaturated fatty acid; and (7 a short carbon chain transfers heat more effectively than a long carbon chain. Palm oil is the optimum base oil of MQL grinding, and this base oil yields 26.98 N tangential grinding force, 87.10 N normal grinding force, 119.6 °C grinding temperature, and 42.7% energy

  8. Effect of Nickel Content on the Corrosion Resistance of Iron-Nickel Alloys in Concentrated Hydrochloric Acid Pickling Solutions

    Directory of Open Access Journals (Sweden)

    Nabeel Alharthi

    2017-01-01

    Full Text Available The effect of Ni content on the resistance against corrosion of Fe-36% Ni and Fe-45% Ni alloys in 1 M hydrochloric acid pickling solution was reported. Various electrochemical and spectroscopic techniques such as potentiodynamic cyclic polarization (CPP, open-circuit potential (OCP, electrochemical impedance spectroscopy (EIS, potentiostatic current-time (PCT, and scanning electron microscopy (SEM, and energy dispersive spectroscopy (EDS have been employed. CPP measurements indicated that the corrosion current and corrosion rate recorded lower values for the alloy that had higher nickel content. OCP curves proved that the presence of high Ni content shifts the absolute potential to the positive potential direction. EIS results revealed that the surface and polarization resistances were much higher for the alloy with higher Ni content. PCT curves also showed that the absolute currents were lower for Fe-45% Ni alloy. All results were in good agreement with others and confirmed clearly that the corrosion resistance in HCl solutions for Fe-45% Ni alloy was higher than that obtained for Fe-45% Ni alloy.

  9. Grain boundary selective oxidation and intergranular stress corrosion crack growth of high-purity nickel binary alloys in high-temperature hydrogenated water

    Energy Technology Data Exchange (ETDEWEB)

    Bruemmer, S. M.; Olszta, M. J.; Toloczko, M. B.; Schreiber, D. K.

    2018-02-01

    The effects of alloying elements in Ni-5at%X binary alloys on intergranular (IG) corrosion and stress corrosion cracking (SCC) have been assessed in 300-360°C hydrogenated water at the Ni/NiO stability line. Alloys with Cr or Al additions exhibited grain boundary oxidation and IGSCC, while localized degradation was not observed for pure Ni, Ni-Cu or Ni-Fe alloys. Environment-enhanced crack growth was determined by comparing the response in water and N2 gas. Results demonstrate that selective grain boundary oxidation of Cr and Al promoted IGSCC of these Ni alloys in hydrogenated water.

  10. Effective and Environmentally Friendly Nickel Coating on the Magnesium Alloy

    OpenAIRE

    Ivana Škugor Rončević; Mirjana Metikoš-Huković; Marijo Buzuk; Nives Vladislavić

    2016-01-01

    The low density and good mechanical properties make magnesium and its alloys attractive construction materials in the electronics, automotive, and aerospace industry, together with application in medicine due to their biocompatibility. Magnesium AZ91D alloy is an alloy with a high content of aluminum, whose mechanical properties overshadow the low corrosion resistance caused by the composition of the alloy and the existence of two phases: α magnesium matrix and β magnesium aluminum intermetal...

  11. Chill block melt spinning of nickel-molybdenum alloys

    Science.gov (United States)

    Hemker, Kevin J.; Glasgow, Thomas K.

    1987-01-01

    Samples of Ni-Mo alloys ranging in composition from pure nickel to Ni-40 at. pct molybdenum were cast by the chill block melt-spinning rapid solidification technique and examined by optical metallography, X-ray diffraction, and microhardness testing. Casting difficulties were encountered with lean alloys, but richer alloys spread more readily on the casting wheel. Alloy microstructures for 5 to 37.5 at. pct molybdenum ribbons were primarily cellular/dendritic; microstructure feature size decreased with increasing molybdenum content. Extended solubility of molybdenum in gamma-nickel, with fcc lattice parameter increasing with composition to the 1.05 power, was observed up to 37/5 at. pct molybdenum. Substoichiometric Ni-Mo (delta) nucleated on the wheel side of the ribbons of compositions 35, 37.5, and 40 at. pct molybdenum. The amount of partitionless delta-phase thus formed increased with increasing molybdenum content and quench rate. This substoichiometric delta transformed readily to a fine structure gamma-delta mixture.

  12. A new composite material-low-carbon Stellite alloy reinforced with nickel-coated carbon fibers

    National Research Council Canada - National Science Library

    Khoddamzadeh, A; Liu, R; Liang, M; Yang, Q

    2014-01-01

    .... The focus of this research is on obviating the problems related to the presence of carbides in Stellite alloys by substituting carbides as the main strengthening agent in Stellite alloys with nickel...

  13. Corrosion of nickel-based dental casting alloys.

    Science.gov (United States)

    Wylie, Christopher M; Shelton, Richard M; Fleming, Garry J P; Davenport, Alison J

    2007-06-01

    To study the microstructure, corrosion behaviour and cell culture response of two nickel-based dental casting alloys before and after a heat treatment to simulate porcelain firing. The microstructure was studied using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). Corrosion behaviour was evaluated by electrochemical measurements in artificial saliva at different values of pH in the presence of a crevice. 3T3 mouse fibroblasts were exposed indirectly to alloy specimens and the number of viable cells counted after 3 and 6 days compared to a control culture. Small changes in microstructure were observed after heat treatment but had a negligible effect on the corrosion properties in the conditions tested. The alloy with a lower bulk level of Cr (12.6 wt.%) showed lower corrosion resistance, indicated by an increased passive current density and this stability was greatly reduced at pH 2.5, where crevice corrosion was observed. Selective dissolution occurred at regions within the microstructure containing lower levels of Cr and Mo. Furthermore, the proliferation of 3T3 mouse fibroblasts was reduced (pcorrosion resistance, which was associated with a more uniform distribution of Cr in the alloy microstructure. The presence of crevices combined with an inhomogeneous distribution of Cr in the microstructure can lead to accelerated corrosion of Ni-based alloys with lower Cr contents. This effect can be avoided by increasing the Cr content of the alloy.

  14. Development and Processing of Nickel Aluminide-Carbide Alloys

    Science.gov (United States)

    Newport, Timothy Scott

    1996-01-01

    With the upper temperature limit of the Ni-based superalloys attained, a new class of materials is required. Intermetallics appear as likely candidates because of their attractive physical properties. With a relatively low density, high thermal conductivity, excellent oxidation resistance, high melting point, and simple crystal structure, nickel aluminide (NiAl) appears to be a potential candidate. However, NiAl is limited in structural applications due to its low room temperature fracture toughness and poor elevated temperature strength. One approach to improving these properties has been through the application of eutectic composites. Researchers have shown that containerless directional solidification of NiAl-based eutectic alloys can provide improvement in both the creep strength and fracture toughness. Although these systems have shown improvements in the mechanical properties, the presence of refractory metals increases the density significantly in some alloys. Lower density systems, such as the carbides, nitrides, and borides, may provide NiAl-based eutectic structure. With little or no information available on these systems, experimental investigation is required. The objective of this research was to locate and develop NiAl-carbide eutectic alloys. Exploratory arc-melts were performed in NiAl-refractory metal-C systems. Refractory metal systems investigated included Co, Cr, Fe, Hf, Mo, Nb, Ta, Ti, W, and Zr. Systems containing carbides with excellent stability (i.e.,HfC, NbC, TaC, TiC, and ZrC) produced large blocky cubic carbides in an NiAl matrix. The carbides appeared to have formed in the liquid state and were randomly distributed throughout the polycrystalline NiAl. The Co, Cr, Fe, Mo, and W systems contained NiAl dendrites with a two-phase interdendritic microconstituent present. Of these systems, the NiAl-Mo-C system had the most promising microstructure for in-situ composites. Three processing techniques were used to evaluate the NiAl-Mo-C system

  15. Intermetallic Nickel-Titanium Alloys for Oil-Lubricated Bearing Applications

    Science.gov (United States)

    DellaCorte, C.; Pepper, S. V.; Noebe, R.; Hull, D. R.; Glennon, G.

    2009-01-01

    An intermetallic nickel-titanium alloy, NITINOL 60 (60NiTi), containing 60 wt% nickel and 40 wt% titanium, is shown to be a promising candidate material for oil-lubricated rolling and sliding contact applications such as bearings and gears. NiTi alloys are well known and normally exploited for their shape memory behavior. When properly processed, however, NITINOL 60 exhibits excellent dimensional stability and useful structural properties. Processed via high temperature, high-pressure powder metallurgy techniques or other means, NITINOL 60 offers a broad combination of physical properties that make it unique among bearing materials. NITINOL 60 is hard, electrically conductive, highly corrosion resistant, less dense than steel, readily machined prior to final heat treatment, nongalling and nonmagnetic. No other bearing alloy, metallic or ceramic encompasses all of these attributes. Further, NITINOL 60 has shown remarkable tribological performance when compared to other aerospace bearing alloys under oil-lubricated conditions. Spiral orbit tribometer (SOT) tests were conducted in vacuum using NITINOL 60 balls loaded between rotating 440C stainless steel disks, lubricated with synthetic hydrocarbon oil. Under conditions considered representative of precision bearings, the performance (life and friction) equaled or exceeded that observed with silicon nitride or titanium carbide coated 440C bearing balls. Based upon this preliminary data, it appears that NITINOL 60, despite its high titanium content, is a promising candidate alloy for advanced mechanical systems requiring superior and intrinsic corrosion resistance, electrical conductivity and nonmagnetic behavior under lubricated contacting conditions.

  16. Nickel and its alloys as perspective materials for intermediate temperature steam electrolysers operating on proton conducting solid acids as electrolyte

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey; Petrushina, Irina; Jensen, Jens Oluf

    2012-01-01

    Several stainless steels, nickel-based alloys, Ta-coated stainless steel, niobium, nickel, platinum and gold were evaluated as possible materials for use in the intermediate temperature water electrolysers. The corrosion resistance was measured in molten KH2PO4 as simulated conditions corresponding...... plates and cell housing. It was shown, that nickel, high-nickel alloys and austenitic stainless steels containing small amounts of Ti have high corrosion resistance in this media. © The Electrochemical Society....... to protonconducting solid acids or transition metal phosphates as electrolytes. It was shown that Au is subject to corrosion in molten KH 2PO4 during polarisation. However, Ni and Ta-coated stainless steel (AISI 316L) demonstrated high corrosion stability and can be recommended as a construction material for bipolar...

  17. Nickel Alloy Primary Water Bulk Surface and SCC Corrosion Film Analytical Characterization and SCC Mechanistic Implications

    Energy Technology Data Exchange (ETDEWEB)

    Morton, D.; Lewis, N.; Hanson, M.; Rice, S.; Sanders, P.

    2007-04-18

    Alloy 600 corrosion coupon tests were performed: (1) to quantify the temperature dependency of general corrosion and (2) to characterize the composition and structure of bulk surface corrosion films for comparison with ongoing primary water SCC (PWSCC) crack tip corrosion film analyses. Results suggest that the thermal activation energy of Alloy 600 corrosion is consistent with the thermal activation energy of nickel alloy PWSCC. Analytical investigations of the structure and composition of Alloy 600 bulk surface corrosion oxides revealed a duplex (inner and outer) oxide layer structure. The outer layer is discontinuous and comprised of relatively large (1 to 3 {micro}m) nickel ferrite crystals and smaller ({approx}0.1 {micro}m) chromium containing nickel ferrite crystals. The inner layer consists of a relatively continuous chromite spinel (major phase) and chromia (Cr{sub 2}O{sub 3} minor phase) which formed through non-selective oxidation. Chromia and dealloyed Alloy 600 (highly Ni enriched metal) were only observed at 337 C (640 F) and only along the boundaries of deformation induced fine grains and subcells. Specimens having deformation free surfaces exhibited continuous uniform inner chromite spinel oxide layers. Specimens with machining induced surface deformation produced non-uniform inner layer oxides (chromite spinel, Cr{sub 2}O{sub 3} and unoxidized material). PWSCC crack tip oxides, in contrast, were fine grain (no duplex structure) and consisted of both chromium rich spinels and ''NiO'' structure oxides. Generally, nickel rich oxides were more abundant under more oxidized conditions (reduced coolant hydrogen) and spinel rich crack tip oxides were favored under more reducing conditions (increased coolant hydrogen). Bulk surface corrosion film thickness did not correlate with observed SCC growth rates. These results suggest that corrosion is not the rate controlling step of PWSCC but rather that PWSCC and corrosion have a common rate

  18. Towards low-friction and wear-resistant plasma sintering dies via plasma surface co-alloying CM247 nickel alloy with V/Ag and N

    Directory of Open Access Journals (Sweden)

    Zhang Zhenxue

    2015-01-01

    Full Text Available Nickel based superalloys have good oxidation and creep resistance and hence they can function under high mechanical stress and high temperatures. However, their undesirable tribological behaviour is the major technical barrier to the challenging high-temperature, lubricant-free plasma sintering tool application. In this study, nickel based CM247 superalloy surfaces were co-alloyed using innovative active screen plasma technology with both interstitial element (e.g. N and substitutional alloying elements (e.g. V and Ag to provide a synergy effect to enhance its tribological properties. The tribological behaviour of the plasma co-alloyed CM247 superalloy surfaces were fully evaluated using reciprocal and pin-on-disc tribometers at temperatures from room temperature to 600 ∘C. The experimental results demonstrate that the co-alloyed surface with N, Ag and V can effectively lower the friction coefficient, which is expected to help demoulding during lubricant-free plasma sintering.

  19. Hot corrosion resistance of nickel-chromium-aluminum alloys

    Science.gov (United States)

    Santoro, G. J.; Barret, C. A.

    1977-01-01

    The hot corrosion resistance of nickel-chromium-aluminum alloys was examined by cyclically oxidizing sodium sulfate-coated specimens in still air at 900, 1000, and 1100 C. The compositions tested were within the ternary region: Ni, Ni-50 at.% Cr, and Ni-50 at.% Al. At each temperature the corrosion data were statistically fitted to a third order regression equation as a function of chromium and aluminum contents. From these equations corrosion isopleths were prepared. Compositional regions with the best hot corrosion resistance were identified.

  20. Preparation of Copper (Cu)-Nickel (Ni) Alloy Thin Films for Bilayer Graphene Growth

    Science.gov (United States)

    2016-02-01

    ARL-TR-7593 ● FEB 2016 US Army Research Laboratory Preparation of Copper (Cu)-Nickel (Ni) Thin Films for Bilayer Graphene Growth...Laboratory Preparation of Copper (Cu)-Nickel (Ni) Alloy Thin Films for Bilayer Graphene Growth by Andrew Chen and Eugene Zakar Sensors and Electron...COVERED (From - To) June–August 2015 4. TITLE AND SUBTITLE Preparation of Copper (Cu)-Nickel (Ni) Alloy Thin Films for Bilayer Graphene Growth 5a

  1. Corrosion Behavior of Amorphous Nickel-Base Alloys in a Boiling Concentrated Sodium Hydroxide Solution

    OpenAIRE

    Kazuo, SHIMAMURA; Kimikado, MIURA; Asahi, Kawashima; Katsuhiko, Asami; Koji, Hashimoto; Institute for Materials Research:Mitsui Engineering & Shipbuilding Co., Ltd.; Institute for Materials Research

    1988-01-01

    Polarization curves were measured in a boiling 50% NaOH solution, and the specimen surface was analyzed by X-ray photoelectron spectroscopy. A combined addition of chromium and molybdenum to amorphous nickel-phosphorus alloys significantly enhances the corrosion resistance. Addition of copper and lead are also effective in improving the corrosion resistance. The surface film formed on amorphous nickel-base alloys consists mainly of hydrated nickel oxyhydroxide. Chromium is concentrated in the...

  2. Temperature effects on the chemical composition of nickel-phosphorus alloy thin films

    Energy Technology Data Exchange (ETDEWEB)

    Oguocha, I.N.A., E-mail: iko340@mail.usask.c [Department of Mechanical Engineering, Engineering Building, 57 Campus Drive, University of Saskatchewan, Saskatoon, SK, S7N 5A9 (Canada); Taheri, R.; Yannacopoulos, S. [School of Engineering, University of British Columbia Okanagan, 3333 University Way, Kelowna, B.C. V1V 1V7 (Canada); Uju, W.A. [Department of Mechanical Engineering, Engineering Building, 57 Campus Drive, University of Saskatchewan, Saskatoon, SK, S7N 5A9 (Canada); Sammynaiken, R., E-mail: r.sammynaiken@usask.c [Saskatchewan Structural Science Centre, University of Saskatchewan, 110 Science Place, Saskatoon, SK, S7N 5C9 (Canada); Wettig, S. [School of Pharmacy, University of Waterloo, 200 University Avenue West, Waterloo, ON, N2L 3G1 (Canada); Hu, Y.-F. [Canadian Light Source Inc., 101 Perimeter Road, Saskatoon, SK, S7N 0X4 (Canada)

    2010-02-01

    Electroless Ni-P (EN) alloys are widely used as coating materials. Their properties depend on the level of phosphorus present and the extent of thermal treatment. We report the results of two complimentary electronic structure techniques, X-ray absorption near edge structure (XANES) and X-ray photoelectron spectroscopy (XPS), and the site-specific surface chemistry in EN alloys of different phosphorus compositions and thermal treatments. In XANES experiment, absorption at the Ni L{sub 3,2} edge and the P K edge were measured and the P 2p, Ni 2p, and Ni 3p bands were measured by XPS. Heating EN alloys to high temperatures result in a competitive reaction between phosphorus and nickel on the surface for oxygen. There is an increase in the level of phosphates and other forms of phosphorus oxides and a decrease in the oxidized nickel on the surface of the EN alloy thin film. Changes in the electronic structure and chemical composition in the bulk of the EN alloy are not obvious.

  3. Standard specification for Nickel-Chromium-Iron alloys (UNS N06600, N06601, N06603, N06690, N06693, N06025, N06045 and N06696), Nickel-Chromium-Cobalt-Molybdenum alloy (UNS N06617), and Nickel-Iron-Chromium-Tungsten alloy (UNS N06674) plate, sheet and strip

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    Standard specification for Nickel-Chromium-Iron alloys (UNS N06600, N06601, N06603, N06690, N06693, N06025, N06045 and N06696), Nickel-Chromium-Cobalt-Molybdenum alloy (UNS N06617), and Nickel-Iron-Chromium-Tungsten alloy (UNS N06674) plate, sheet and strip

  4. Standard specification for Nickel-Chromium-Iron alloys (UNS N06600, N06601, N06603, N06690, N06693, N06025, N06045, and N06696), Nickel-Chromium-Cobalt-Molybdenum alloy (UNS N06617), and Nickel-Iron-Chromium-Tungsten alloy (UNS N06674) rod, bar, and wire

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    Standard specification for Nickel-Chromium-Iron alloys (UNS N06600, N06601, N06603, N06690, N06693, N06025, N06045, and N06696), Nickel-Chromium-Cobalt-Molybdenum alloy (UNS N06617), and Nickel-Iron-Chromium-Tungsten alloy (UNS N06674) rod, bar, and wire

  5. Solid particle erosion of steels and nickel based alloys candidates for USC steam turbine blading

    Energy Technology Data Exchange (ETDEWEB)

    Cernuschi, Federico; Guardamagna, Cristina; Lorenzoni, Lorenzo [ERSE SpA, Milan (Italy); Robba, Davide [CESI, Milan (Italy)

    2010-07-01

    The main objective of COST536 Action is to develop highly efficient steam power plant with low emissions, from innovative alloy development to validation of component integrity. In this perspective, to improve the operating efficiency, materials capable of withstanding higher operating temperatures are required. For the manufacturing of components for steam power plants with higher efficiency steels and nickel-based alloys with improved oxidation resistance and creep strength at temperature as high as 650 C - 700 C have to be developed. Candidate alloys for manufacturing high pressure steam turbine diaphragms, buckets, radial seals and control valves should exhibit, among other properties, a good resistance at the erosion phenomena induced by hard solid particles. Ferric oxide (magnetite) scales cause SPE by exfoliating from boiler tubes and steam pipes (mainly super-heaters and re-heaters) and being transported within the steam flow to the turbine. In order to comparatively study the erosion behaviour of different materials in relatively short times, an accelerated experimental simulation of the erosion phenomena must be carried out. Among different techniques to induce erosion on material targets, the use of an air jet tester is well recognised to be one of the most valid and reliable. In this work the results of SPE comparative tests performed at high temperatures (550 C, 600 C and 650 C) at different impaction angles on some steels and nickel based alloys samples are reported. (orig.)

  6. Assessment of corrosion resistance of cast cobalt- and nickel-chromium dental alloys in acidic environments.

    Science.gov (United States)

    Mercieca, Sven; Caligari Conti, Malcolm; Buhagiar, Joseph; Camilleri, Josette

    2017-10-26

    The aim of this study was to compare the degradation resistance of nickel-chromium (Ni-Cr) and cobalt-chromium (Co-Cr) alloys used as a base material for partial dentures in contact with saliva. Wiron® 99 and Wironit Extra-Hard® were selected as representative casting alloys for Ni-Cr and Co-Cr alloys, respectively. The alloys were tested in contact with deionized water, artificial saliva and acidified artificial saliva. Material characterization was performed by X-ray diffractometry (XRD) and microhardness and nanohardness testing. The corrosion properties of the materials were then analyzed using open circuit potential analysis and potentiodynamic analysis. Alloy leaching in solution was assessed by inductively coupled plasma mass spectrometry techniques. Co-Cr alloy was more stable than the Ni-Cr alloy in all solutions tested. Leaching of nickel and corrosion attack was higher in Ni-Cr alloy in artificial saliva compared with the acidified saliva. The corrosion resistance of the Co-Cr alloy was seen to be superior to that of the Ni-Cr alloy, with the former exhibiting a lower corrosion current in all test solutions. Microstructural topographical changes were observed for Ni-Cr alloy in contact with artificial saliva. The Ni-Cr alloy exhibited microstructural changes and lower corrosion resistance in artificial saliva. The acidic changes did not enhance the alloy degradation. Ni-Cr alloys are unstable in solution and leach nickel. Co-Cr alloys should be preferred for clinical use.

  7. Simultaneous material flow analysis of nickel, chromium, and molybdenum used in alloy steel by means of input-output analysis.

    Science.gov (United States)

    Nakajima, Kenichi; Ohno, Hajime; Kondo, Yasushi; Matsubae, Kazuyo; Takeda, Osamu; Miki, Takahiro; Nakamura, Shinichiro; Nagasaka, Tetsuya

    2013-05-07

    Steel is not elemental iron but rather a group of iron-based alloys containing many elements, especially chromium, nickel, and molybdenum. Steel recycling is expected to promote efficient resource use. However, open-loop recycling of steel could result in quality loss of nickel and molybdenum and/or material loss of chromium. Knowledge about alloying element substance flow is needed to avoid such losses. Material flow analyses (MFAs) indicate the importance of steel recycling to recovery of alloying elements. Flows of nickel, chromium, and molybdenum are interconnected, but MFAs have paid little attention to the interconnected flow of materials/substances in supply chains. This study combined a waste input-output material flow model and physical unit input-output analysis to perform a simultaneous MFA for nickel, chromium, and molybdenum in the Japanese economy in 2000. Results indicated the importance of recovery of these elements in recycling policies for end-of-life (EoL) vehicles and constructions. Improvement in EoL sorting technologies and implementation of designs for recycling/disassembly at the manufacturing phase are needed. Possible solutions include development of sorting processes for steel scrap and introduction of easier methods for identifying the composition of secondary resources. Recovery of steel scrap with a high alloy content will reduce primary inputs of alloying elements and contribute to more efficient resource use.

  8. Erosion-Corrosion of Iron and Nickel Alloys at Elevated Temperature in a Combustion Gas Environment

    Energy Technology Data Exchange (ETDEWEB)

    Tylczak, Joseph [National Energy Technology Lab. (NETL), Albany, OR (United States)

    2014-05-02

    This paper reports on the results of a study that compares the erosion-corrosion behavior of a variety of alloys (Fe- 2¼Cr 1Mo, 304 SS, 310 SS, Incoloy 800, Haynes 230 and a Fe3Al) in a combustion environment. Advanced coal combustion environments, with higher temperatures, are driving re-examination of traditional and examination of new alloys in these hostile environments. In order to simulate conditions in advanced coal combustion boilers, a special erosion apparatus was used to allow for impingement of particles under a low abrasive flux in a gaseous environment comprised of 20 % CO2, 0.05 % HCl, 77 % N2, 3 % O2, and 0.1 % SO2. Tests were conducted at room temperature and 700 °C with ~ 270 μm silica, using an impact velocity of 20 m/s in both air and the simulated combustion gas environment. The erosion-corrosion behavior was characterized by gravimetric measurements and by examination of the degraded surfaces optically and by scanning electron microscopy (SEM). At room temperature most of the alloys had similar loss rates. Not surprisingly, at 700 °C the lower chrome-iron alloy had a very high loss rate. The nickel alloys tended to have higher loss rates than the high chrome austenitic alloys.

  9. Metallic ions released from stainless steel, nickel-free, and titanium orthodontic alloys: toxicity and DNA damage.

    Science.gov (United States)

    Ortiz, Antonio José; Fernández, Esther; Vicente, Ascensión; Calvo, José L; Ortiz, Clara

    2011-09-01

    The aims of this study were to determine the amounts of metallic ions that stainless steel, nickel-free, and titanium alloys release to a culture medium, and to evaluate the cellular viability and DNA damage of cultivated human fibroblasts with those mediums. The metals were extracted from 10 samples (each consisting of 4 buccal tubes and 20 brackets) of the 3 orthodontic alloys that were submerged for 30 days in minimum essential medium. Next, the determination of metals was performed by using inductively coupled plasma mass spectrometry, cellular viability was assessed by using the tetrazolium reduction assay (MTT assay) (3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide), and DNA damage was determined with the Comet assay. The metals measured in all the samples were Ti(47), Cr(52), Mn(55), Co(59), Ni(60), Mo(92), Fe(56), Cu(63), Zn(66), As(75), Se(78), Cd(111), and Pb(208). The cellular viability of the cultured fibroblasts incubated for 7 days with minimum essential medium, with the stainless steel alloy submerged, was close to 0%. Moreover, high concentrations of titanium, chromium, manganese, cobalt, nickel, molybdenum, iron, copper, and zinc were detected. The nickel-free alloy released lower amounts of ions to the medium. The greatest damage in the cellular DNA, measured as the olive moment, was also produced by the stainless steel alloy followed by the nickel-free alloy. Conversely, the titanium alloy had an increased cellular viability and did not damage the cellular DNA, as compared with the control values. The titanium brackets and tubes are the most biocompatible of the 3 alloys studied. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  10. Alloy development and mechanical properties of nickel aluminide (Ni sub 3 Al) alloys

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.T.; Sikka, V.K.; Horton, J.A.; Lee, E.H.

    1988-08-01

    This report summarizes recent alloy development of nickel aluminides for structural applications. Boron-doped Ni{sub 3}Al showed severe embrittlement when tested in oxidizing environments above 300{degrees}C. The embrittlement is due to a dynamic effect, which can be alleviated by alloying with 8 at. % Cr. The chromium-modified aluminide alloys possess a good combination of strength and ductility for use at temperatures to 1000{degrees}C. The hot ductility and fabricability of the aluminide alloys can be substantially improved by reducing the zirconium content to below 0.35 at. %. Material processing of large aluminide heats has been demonstrated by both conventional and innovative techniques. Mechanical properties of the aluminide alloys were characterized at temperatures to 1200{degrees}C. Grain size, which is the main difference between the materials produced by the various processing techniques, is the major metallurgical parameter that strongly influences the mechanical properties of the aluminide alloys. 35 refs., 20 figs., 11 tabs.

  11. Influence of microstructure on the shape memory properties of two titanium-lean, nickel-titanium-platinum high temperature shape memory alloys

    Science.gov (United States)

    Hudish, Grant A.

    Because of NiTi's superior properties (work output, strength, ductility, recoverable strain, etc.) it is the base system of choice for development of derivative high-temperature shape memory alloys (HTSMAs). Ternary additions of Hf, Zr, Pt, Pd, and Au can be made, in quantities greater than ≈ 10 at.%, to increase the transformation temperature of Ni-Ti based SMAs. Pt as an alloying addition is attractive because of (1) its efficiency in raising the martensitic transformation temperature, (2) the relatively stable properties during thermal cycling of Pt-containing Nitinol (NiTi), and (3) the high work outputs of Ni-Ti-Pt alloys relative to other HTSMAs. Platinum containing samples of NiTi were thermally processed to explore the utility of Ti-lean precipitates for matrix strengthening and stabilization of shape memory properties during thermomechanical cycling. Two alloys, Ti48.5Ni30.5Pt 21 and Ti49.5Ni29.5Pt21, were heat treated for 1, 5, 24 and 100h at 500, 550, 600, 650, and 700°C and examined using SEM, EDS, DTA, XRD and TEM techniques. Two relevant precipitate phases, the PL and Ti2(Ni,Pt)3 phases, were identified, characterized and the thermodynamic stability and relevant behavior during thermal processing determined. Samples were then subjected to thermomechanical testing that consisted of two parts, (1) two thermal cycles (75°C to 500°C to 75°C) each at stresses of 0, 50, 100, 150, 200, 250, and 300MPa, and (2) 100 thermal cycles at 200MPa. With this combination of systematic microstructural characterization and isobaric thermal cycling, the link between microstructure and shape memory performance was made. The influence the PL and Ti2(Ni,Pt)3 phases have on properties such as martensitic transformation temperatures, transformation strain, and accumulated irrecoverable strain are explained and discussed. Specifically, it was found that the P L-phase suppresses transformation temperatures and strains through a matrix strengthening effect, but also

  12. Mechanical properties of metal-ceramic systems from nickel-chromium and cobalt-chromium alloys

    OpenAIRE

    Mirković Nemanja

    2007-01-01

    Background/Aim. Metal-ceramic bond strength and alloys' elastic modulus clearly determine the potential of alloy application, because the ceramic integrity during mastication depends on these two characteristics. The aim of this study was to evaluate metal-ceramic bond strength and elastic modulus of cobalt-chromium alloys in making porcelainfused- to-metal restorations, regarding the application of the most frequent nickel-chromium alloy. Methods. The research was performed as an experimenta...

  13. Mechanical properties of metal-ceramic systems from nickel-chromium and cobalt-chromium alloys

    Directory of Open Access Journals (Sweden)

    Mirković Nemanja

    2007-01-01

    Full Text Available Background/Aim. Metal-ceramic bond strength and alloys' elastic modulus clearly determine the potential of alloy application, because the ceramic integrity during mastication depends on these two characteristics. The aim of this study was to evaluate metal-ceramic bond strength and elastic modulus of cobalt-chromium alloys in making porcelainfused- to-metal restorations, regarding the application of the most frequent nickel-chromium alloy. Methods. The research was performed as an experimental study. Six metalceramic samples were made from nickel-chromium alloy (Wiron 99 and cobalt-chromium alloy (Wirobond C, according to the manufactures manuals and instructions from ISO 9693: 1996. Three-point bending test was performed up to the ceramic fracture. The fracture load was measured on an universal testing machine (Zwick, type 1464, with cross-head speed of 0,05mm/min. Results. The results of this study confirmed the significant differences between the metal-ceramic bond strength (p < 0.01 and elastic modulus (p < 0.001 of nickel-chromium and cobalt-chromium alloys, where cobalt-chromium alloys showed higher values for both tested parameters. Conclusion. Cobalt-chromium metal-ceramic alloys can successfully replace nickel-chromium alloys, especially for fabrication of long-span metal-ceramic bridges due to the great flexural strength.

  14. Evaluation and comparison of shear bond strength of porcelain to a beryllium-free alloy of nickel-chromium, nickel and beryllium free alloy of cobalt-chromium, and titanium: An in vitro study

    Directory of Open Access Journals (Sweden)

    Ananya Singh

    2017-01-01

    Conclusion: It could be concluded that newer nickel and beryllium free Co-Cr alloys and titanium alloys with improved strength to weight ratio could prove to be good alternatives to the conventional nickel-based alloys when biocompatibility was a concern.

  15. Alloys for hydrogen storage in nickel/hydrogen and nickel/metal hydride batteries

    Science.gov (United States)

    Anani, Anaba; Visintin, Arnaldo; Petrov, Konstantin; Srinivasan, Supramaniam; Reilly, James J.; Johnson, John R.; Schwarz, Ricardo B.; Desch, Paul B.

    1993-01-01

    Since 1990, there has been an ongoing collaboration among the authors in the three laboratories to (1) prepare alloys of the AB(sub 5) and AB(sub 2) types, using arc-melting/annealing and mechanical alloying/annealing techniques; (2) examine their physico-chemical characteristics (morphology, composition); (3) determine the hydrogen absorption/desorption behavior (pressure-composition isotherms as a function of temperature); and (4) evaluate their performance characteristics as hydride electrodes (charge/discharge, capacity retention, cycle life, high rate capability). The work carried out on representative AB(sub 5) and AB(sub 2) type modified alloys (by partial substitution or with small additives of other elements) is presented. The purpose of the modification was to optimize the thermodynamics and kinetics of the hydriding/dehydriding reactions and enhance the stabilities of the alloys for the desired battery applications. The results of our collaboration, to date, demonstrate that (1) alloys prepared by arc melting/annealing and mechanical alloying/annealing techniques exhibit similar morphology, composition and hydriding/dehydriding characteristics; (2) alloys with the appropriate small amounts of substituent or additive elements: (1) retain the single phase structure, (2) improve the hydriding/dehydriding reactions for the battery applications, and (3) enhance the stability in the battery environment; and (3) the AB(sub 2) type alloys exhibit higher energy densities than the AB(sub 5) type alloys but the state-of-the-art, commercialized batteries are predominantly manufactured using Ab(sub 5) type alloys.

  16. Studies on the Codeposition of SiC Nanopowder with Nickel, Cobalt, and Co-Ni Alloys

    Directory of Open Access Journals (Sweden)

    Ewa Rudnik

    2014-01-01

    Full Text Available Electrodeposition of SiC nanopowder (approximately 120 nm with nickel, cobalt, and Co-Ni alloy matrix was studied. It was found that particles suspended in the bath affect slightly the reduction of metallic ions. Incorporation of the ceramic particles was governed mainly by the morphology of the matrix surface, while no strict correlation between the amount of cobalt ions adsorbed on the powder and the SiC content in the composites was found. Microhardness of nickel deposits was 585±5 HV, while for cobalt-rich coatings (84–95 wt.% Co the values were in the range of 260–290 HV, independently of the SiC content in the coatings. Fine-grained nickel deposits were characterized by good corrosion resistance, while cobalt and Co-Ni alloys showed high corrosion current densities.

  17. Simulation of Low Nickel Content Alloys For Industrial Ground Fault Circuit-Breaker Relays

    OpenAIRE

    Messal, Oualid; Sixdenier, Fabien; Morel, Laurent; Burais, Noël; Waeckerle, Thierry

    2014-01-01

    International audience; The aim of this paper is to simulate the performances of a ground fault circuit-breaker (GFCB) relay with new low nickel content alloys. Indeed, in the construction industry, the materials become more expensive as their nickel content increases. Moreover, the demand for nickel is particularly sensitive to the economic conjuncture. Therefore, an original electromagnetic relay model has been developed and validated in different working conditions (current amplitude, freq...

  18. The electrochemical deposition of tin-nickel alloys and the corrosion properties of the coating

    DEFF Research Database (Denmark)

    Jellesen, Morten Stendahl; Møller, Per

    2005-01-01

    electrodeposition. The alloy has unique corrosion properties and exhibits surface passivation like stainless steel. The coating is decorative and non-allergic to the skin, can replace decorative nickel and nickel-chromium coatings in many cases and decreases the risk for allergic contact dermatitis. A number...

  19. Creep and stress rupture of a mechanically alloyed oxide dispersion and precipitation strengthened nickel-base superalloy

    Science.gov (United States)

    Howson, T. E.; Tien, J. K.; Mervyn, D. A.

    1980-01-01

    The creep and stress rupture behavior of a mechanically alloyed oxide dispersion strengthened (ODS) and gamma-prime precipitation strengthened nickel-base alloy (alloy MA 6000E) was studied at intermediate and elevated temperatures. At 760 C, MA 6000E exhibits the high creep strength characteristic of nickel-base superalloys and at 1093 C the creep strength is superior to other ODS nickel-base alloys. The stress dependence of the creep rate is very sharp at both test temperatures and the apparent creep activation energy measured around 760 C is high, much larger in magnitude than the self-diffusion energy. Stress rupture in this large grain size material is transgranular and crystallographic cracking is observed. The rupture ductility is dependent on creep strain rate, but usually is low. These and accompanying microstructural results are discussed with respect to other ODS alloys and superalloys and the creep behavior is rationalized by invoking a recently-developed resisting stress model of creep in materials strengthened by second phase particles.

  20. Thresholds of time dependent intergranular crack growth in a nickel disc alloy Alloy 720Li

    Directory of Open Access Journals (Sweden)

    Li Hangyue

    2014-01-01

    Full Text Available At high temperatures in air, introducing a dwell period at the peak stress of fatigue cycles promotes time dependent intergranular crack growth which can increase crack growth rates by upto a few orders of magnitude from the rates of transgranular fatigue crack growth in superalloys. It is expected that time dependent intergranular crack growth in nickel-based superalloys may not occur below a critical mechanical driving force, ΔKth−IG, analogous to a fatigue threshold (ΔKth and a critical temperature, Tth. In this study, dwell fatigue crack growth tests have been carefully designed and conducted on Alloy 720Li to examine such thresholds. Unlike a fatigue threshold, the threshold stress intensity factor range for intergranular crack growth is observed to be highly sensitive to microstructure, dwell time and test procedure. The near threshold crack growth behaviour is made complex by the interactions between grain boundary oxidation embrittlement and crack tip stress relaxation. In general, lower ΔKth−IG values are associated with finer grain size and/or shorter dwell times. Often a load increasing procedure promotes stress relaxation and tends to lead to higher ΔKth−IG. When there is limited stress relaxation at the crack tip, similar ΔKth−IG values are measured with load increasing and load shedding procedures. They are generally higher than the fatigue threshold (ΔKth despite faster crack growth rates (da/dN in the stable crack growth regime. Time dependent intergranular crack growth cannot be activated below a temperature of 500 ∘C.

  1. Development of highly sensitive extractive spectrophotometric determination of nickel(II) in medicinal leaves, soil, industrial effluents and standard alloy samples using pyridoxal-4-phenyl-3-thiosemicarbazone.

    Science.gov (United States)

    Sarma, Loka Subramanyam; Kumar, Jyothi Rajesh; Reddy, Koduru Janardhan; Thriveni, Thenepalli; Reddy, Ammireddy Varada

    2008-01-01

    Pyridoxal-4-phenyl-3-thiosemicarbazone (PPT) is proposed as a new sensitive reagent for the extractive spectrophotometric determination of nickel(II). PPT reacts with nickel(II) in the pH range 4.0-6.0 to form a reddish brown colored complex, which was well-extracted into n-butanol. The absorbance value of the Ni(II)-PPT complex was measured at different time intervals at 430nm, to ascertain the stability of the complex. The system obeyed Beer's law up to 0.5-5.0microgmL(-1) of nickel(II), with an excellent linearity in terms of the correlation coefficient value of 0.99. The molar absorptivity and Sandell's sensitivity of the extracted species are 1.92 x 10(4)Lmol(-1)cm(-1) and 0.003057microgcm(-2) respectively at 430nm. The detection limit of the method is 0.069microgmL(-1). To assess precision and accuracy of the developed method, determinations were carried out at different concentrations. The relative standard deviation of all measurements does not exceed 2.62%. The developed method has been satisfactorily applied for the determination of nickel(II), when present alone or in the presence of diverse ions, which are usually associated with nickel(II) in medicinal leaves, soil and industrial effluent samples. Various standard and certified reference materials (CM 247 LC, IN 718, BCS 233, 266, 253 and 251) have also been tested for the determination of nickel for the purpose of validation of the present method. The results of the proposed method are compared with those obtained from an atomic absorption spectrometer (AAS).

  2. Comparison of joining processes for Haynes 230 nickel based super alloy

    Science.gov (United States)

    Williston, David Hugh

    Haynes 230 is a nickel based, solid-solution strengthened alloy that is used for high-temperature applications in the aero-engine and power generation industries. The alloy composition is balanced to avoid precipitation of undesirable topologically closed-packed (TCP) intermetallic phases, such as Sigma, Mu, or Laves-type, that are detrimental to mechanical and corrosion properties. This material is currently being used for the NASA's J2X upper stage rocket nozzle extension. Current fabrication procedures use fusion welding processes to join blanks that are subsequently formed. Cracks have been noted to occur in the fusion welded region during the forming operations. Use of solid state joining processes, such as friction stir welding are being proposed to eliminate the fusion weld cracks. Of interest is a modified friction stir welding process called thermal stir welding. Three welding process: Gas Metal Arc Welding (GMAW), Electron Beam Welding (EBW), and Thermal Stir Welding (TSWing) are compared in this study.

  3. Segregation-induced ordered superstructures at general grain boundaries in a nickel-bismuth alloy

    Science.gov (United States)

    Yu, Zhiyang; Cantwell, Patrick R.; Gao, Qin; Yin, Denise; Zhang, Yuanyao; Zhou, Naixie; Rohrer, Gregory S.; Widom, Michael; Luo, Jian; Harmer, Martin P.

    2017-10-01

    The properties of materials change, sometimes catastrophically, as alloying elements and impurities accumulate preferentially at grain boundaries. Studies of bicrystals show that regular atomic patterns often arise as a result of this solute segregation at high-symmetry boundaries, but it is not known whether superstructures exist at general grain boundaries in polycrystals. In bismuth-doped polycrystalline nickel, we found that ordered, segregation-induced grain boundary superstructures occur at randomly selected general grain boundaries, and that these reconstructions are driven by the orientation of the terminating grain surfaces rather than by lattice matching between grains. This discovery shows that adsorbate-induced superstructures are not limited to special grain boundaries but may exist at a variety of general grain boundaries, and hence they can affect the performance of polycrystalline engineering alloys.

  4. Method for inhibiting alkali metal corrosion of nickel-containing alloys

    Science.gov (United States)

    DeVan, Jackson H.; Selle, James E.

    1983-01-01

    Structural components of nickel-containing alloys within molten alkali metal systems are protected against corrosion during the course of service by dissolving therein sufficient aluminum, silicon, or manganese to cause the formation and maintenance of a corrosion-resistant intermetallic reaction layer created by the interaction of the molten metal, selected metal, and alloy.

  5. [Mechanical properties of metal-ceramic systems from nickel-chromium and cobalt-chromium alloys].

    Science.gov (United States)

    Mirković, Nemanja

    2007-04-01

    Metal-ceramic bond strength and alloys' elastic modulus clearly determine the potential of alloy application, because the ceramic integrity during mastication depends on these two characteristics. The aim of this study was to evaluate metal-ceramic bond strenght and elastic modulus of cobalt-chromium alloys in making porcelain-fused-to-metal restorations, regarding the application of the most frequent nickel-chromium alloy. The research was performed as an experimental study. Six metal-ceramic samples were made from nickel-chromium alloy (Wiron 99) and cobalt-chromium alloy (Wirobond C), according to the manufactures manuals and instructions from ISO 9693: 1996. Three-point bending test was performed up to the ceramic fracture. The fracture load was measured on an universal testing machine (Zwick, type 1464), with cross-head speed of 0,05mm/min. The results of this study confirmed the significant differences between the metal-ceramic bond strength (p chromium and cobalt-chromium alloys, where cobalt-chromium alloys showed higher values for both tested parameters. Cobalt-chromium metal-ceramic alloys can successfully replace nickel-chromium alloys, especially for fabrication of long-span metal-ceramic bridges due to the great flexural strength.

  6. Nickel-silver alloy electrocatalysts for hydrogen evolution and oxidation in an alkaline electrolyte.

    Science.gov (United States)

    Tang, Maureen H; Hahn, Christopher; Klobuchar, Aidan J; Ng, Jia Wei Desmond; Wellendorff, Jess; Bligaard, Thomas; Jaramillo, Thomas F

    2014-09-28

    The development of improved catalysts for the hydrogen evolution reaction (HER) and hydrogen oxidation reaction (HOR) in basic electrolytes remains a major technical obstacle to improved fuel cells, water electrolyzers, and other devices for electrochemical energy storage and conversion. Based on the free energy of adsorbed hydrogen intermediates, theory predicts that alloys of nickel and silver are active for these reactions. In this work, we synthesize binary nickel-silver bulk alloys across a range of compositions and show that nickel-silver alloys are indeed more active than pure nickel for hydrogen evolution and, possibly, hydrogen oxidation. To overcome the mutual insolubility of silver and nickel, we employ electron-beam physical vapor codeposition, a low-temperature synthetic route to metastable alloys. This method also produces flat and uniform films that facilitate the measurement of intrinsic catalytic activity with minimal variations in the surface area, ohmic contact, and pore transport. Rotating-disk-electrode measurements demonstrate that the hydrogen evolution activity per geometric area of the most active catalyst in this study, Ni0.75Ag0.25, is approximately twice that of pure nickel and has comparable stability and hydrogen oxidation activity. Our experimental results are supported by density functional theory calculations, which show that bulk alloying of Ni and Ag creates a variety of adsorption sites, some of which have near-optimal hydrogen binding energy.

  7. Thermal Analysis in the Technological “Step” Test of H282 Nickel Alloy

    Directory of Open Access Journals (Sweden)

    Pirowski Z.

    2015-03-01

    Full Text Available Superalloys show a good combination of mechanical strength and resistance to surface degradation under the influence of chemically active environments at high temperature. They are characterized by very high heat and creep resistance. Their main application is in gas turbines, chemical industry, and in all those cases where resistance to creep and the aggressive corrosion environment is required. Modern jet engines could never come into use if not for progress in the development of superalloys. Superalloys are based on iron, nickel and cobalt. The most common and the most interesting group includes superalloys based on nickel. They carry loads at temperatures well in excess of the eighty percent of the melting point. This group includes the H282 alloy, whose nominal chemical composition is as follows (wt%: Ni - base, Fe - max. 1.5%, Al - 1.5% Ti - 2.1%, C - 0.06% Co - 10% Cr - 20% Mo - 8.5%. This study shows the results of thermal analysis of the H282 alloy performed on a cast step block with different wall thickness. Using the results of measurements, changes in the temperature of H282 alloy during its solidification were determined, and the relationship dT / dt = f (t was derived. The results of the measurements taken at different points in the cast step block allowed identifying a number of thermal characteristics of the investigated alloy and linking the size of the dendrites formed in a metal matrix (DAS with the thermal effect of solidification. It was found that the time of solidification prolonged from less than ome minute at 10 mm wall thickness to over seven minutes at the wall thickness of 44 mm doubled the value of DAS.

  8. Electrochemical studies of copper, nickel and a Cu55/Ni45 alloy in aqueous sodium acetate

    Directory of Open Access Journals (Sweden)

    Gonçalves Reinaldo Simões

    2001-01-01

    Full Text Available This paper discusses the electrochemical behavior of copper, nickel and a copper/nickel alloy in aerated aqueous 0.10 and 1.0 mol L-1 sodium acetate. The data obtained from different electrochemical techniques were analyzed to determine the influence of Ni and Cu on the electrochemical processes of the alloy electrode. The shapes of the potentiodynamic I(E curves of the alloy were found to be quite similar to those of the Ni voltamograms. Although the anodic current densities of Ni and the alloy increased with greater concentrations of acetate, the opposite effect occurred in Cu. The impedance measurements taken at the open circuit potential revealed that the polarization resistance (R P of the electrodes decreased in the following order: Ni > Alloy > Cu. With increasing concentrations of acetate, the R P of the alloy and the Cu increased while that of the Ni electrode decreased.

  9. Corrosion resistance of nickel-based alloys in salt and metal melts containing REE

    Science.gov (United States)

    Abramov, A. V.; Karpov, V. V.; Zhilyakov, A. Yu.; Belikov, S. V.; Volkovich, V. A.; Polovov, I. B.; Rebrin, O. I.

    2017-09-01

    The corrosion resistance of Hastelloy G-35 and VDM® Alloy 625 nickel alloys was studied in a wide temperature range (750-1100 °C) in fused LiCl, CaCl2, NaCl-KCl, LiF mixtures containing REE. The rates and the mechanisms of the corrosion of the materials studied were determined. The processes taking place during the interaction between alloys and melts were investigated.

  10. Co-reduction of Copper Smelting Slag and Nickel Laterite to Prepare Fe-Ni-Cu Alloy for Weathering Steel

    Science.gov (United States)

    Guo, Zhengqi; Pan, Jian; Zhu, Deqing; Zhang, Feng

    2018-02-01

    In this study, a new technique was proposed for the economical and environmentally friendly recovery of valuable metals from copper smelting slag while simultaneously upgrading nickel laterite through a co-reduction followed by wet magnetic separation process. Copper slag with a high FeO content can decrease the liquidus temperature of the SiO2-Al2O3-CaO-MgO system and facilitate formation of liquid phase in a co-reduction process with nickel laterite, which is beneficial for metallic particle growth. As a result, the recovery of Ni, Cu, and Fe was notably increased. A crude Fe-Ni-Cu alloy with 2.5% Ni, 1.1% Cu, and 87.9% Fe was produced, which can replace part of scrap steel, electrolytic copper, and nickel as the burden in the production of weathering steel by an electric arc furnace. The study further found that an appropriate proportion of copper slag and nickel laterite in the mixture is essential to enhance the reduction, acquire appropriate amounts of the liquid phase, and improve the growth of the metallic alloy grains. As a result, the liberation of alloy particles in the grinding process was effectively promoted and the metal recovery was increased significantly in the subsequent magnetic separation process.

  11. Co-reduction of Copper Smelting Slag and Nickel Laterite to Prepare Fe-Ni-Cu Alloy for Weathering Steel

    Science.gov (United States)

    Guo, Zhengqi; Pan, Jian; Zhu, Deqing; Zhang, Feng

    2017-11-01

    In this study, a new technique was proposed for the economical and environmentally friendly recovery of valuable metals from copper smelting slag while simultaneously upgrading nickel laterite through a co-reduction followed by wet magnetic separation process. Copper slag with a high FeO content can decrease the liquidus temperature of the SiO2-Al2O3-CaO-MgO system and facilitate formation of liquid phase in a co-reduction process with nickel laterite, which is beneficial for metallic particle growth. As a result, the recovery of Ni, Cu, and Fe was notably increased. A crude Fe-Ni-Cu alloy with 2.5% Ni, 1.1% Cu, and 87.9% Fe was produced, which can replace part of scrap steel, electrolytic copper, and nickel as the burden in the production of weathering steel by an electric arc furnace. The study further found that an appropriate proportion of copper slag and nickel laterite in the mixture is essential to enhance the reduction, acquire appropriate amounts of the liquid phase, and improve the growth of the metallic alloy grains. As a result, the liberation of alloy particles in the grinding process was effectively promoted and the metal recovery was increased significantly in the subsequent magnetic separation process.

  12. Electron Beam Welding Characteristics of Cast Iron and Bonding of Mild Steel to Cast Iron by using Iron-base Alloy of High Nickel Content

    Science.gov (United States)

    Hatate, Minoru; Shiota, Toshio; Nagasaki, Yoichi; Abe, Nobuyuki; Amano, Masaharu; Tanaka, Toshio

    Bonding characteristics of mild steel to cast iron using electron beam welding (EBW) process are investigated from the viewpoint of microstructure and mechanical properties. When the electron beam is radiated to a cast iron, remelting of the surface and corresponding rapid cooling take place, and it results in formation of brittle fine-cementite structure whose hardness is over 700 Hv. As Ni is an alloying element that may prevent formation of cementite, we compare two kinds of welding methods with Ni addition. One method is EBW process, radiating the electron beam to a thin plate made of spheroidal graphite cast iron with a high Ni content after the plate inserts between cast iron and steel, and other one is a metal active gas (MAG) welding process using a Fe-Ni wire. Bonding tensile strength by EBW process is higher than that by MAG welding process. In case of welding of cast iron and other metallic material, EBW process is found to be more advantageous than MAG welding process.

  13. MACHINING OF NICKEL BASED ALLOYS USING DIFFERENT CEMENTED CARBIDE TOOLS

    Directory of Open Access Journals (Sweden)

    BASIM A. KHIDHIR

    2010-09-01

    Full Text Available This paper presents the results of experimental work in dry turning of nickel based alloys (Haynes – 276 using Deferent tool geometer of cemented carbide tools. The turning tests were conducted at three different cutting speeds (112, 152, 201and 269 m/min while feed rate and depth of cut were kept constant at 0.2 mm/rev and 1.5 mm, respectively. The tool holders used were SCLCR with insert CCMT-12 and CCLNR – M12-4 with insert CNGN-12. The influence of cutting speed, tool inserts type and workpiece material was investigated on the machined surface roughness. The worn parts of the cutting tools were also examined under scanning electron microscope (SEM. The results showed that cutting speed significantly affected the machined surface finish values in related with the tool insert geometry. Insert type CCMT-12 showed better surface finish for cutting speed to 201 m/min, while insert type CNGN-12 surface roughness increased dramatically with increasing of speed to a limit completely damage of insert geometer beyond 152 m/min.

  14. Fracture behavior of nickel-based alloys in water

    Energy Technology Data Exchange (ETDEWEB)

    Mills, W.J.; Brown, C.M.

    1999-08-01

    The cracking resistance of Alloy 600, Alloy 690 and their welds, EN82H and EN52, was characterized by conducting J{sub IC} tests in air and hydrogenated water. All test materials displayed excellent toughness in air and high temperature water, but Alloy 690 and the two welds were severely embrittled in low temperature water. In 54 C water with 150 cc H{sub 2}/kg H{sub 2}O, J{sub IC} values were typically 70% to 95% lower than their air counterparts. The toughness degradation was associated with a fracture mechanism transition from microvoid coalescence to intergranular fracture. Comparison of the cracking response in water with that for hydrogen-precharged specimens tested in air demonstrated that susceptibility to low temperature cracking is due to hydrogen embrittlement of grain boundaries. The effects of water temperature, hydrogen content and loading rate on low temperature crack propagation were studied. In addition, testing of specimens containing natural weld defects and as-machined notches was performed to determine if low temperature cracking can initiate at these features. Unlike the other materials, Alloy 600 is not susceptible to low temperature cracking as the toughness in 54 C water remained high and a microvoid coalescence mechanism was operative in both air and water.

  15. Nonequilibrium Phase Chemistry in High Temperature Structure Alloys

    Science.gov (United States)

    Wang, R.

    1991-01-01

    Titanium and nickel aluminides of nonequilibrium microstructures and in thin gauge thickness were identified, characterized and produced for potential high temperature applications. A high rate sputter deposition technique for rapid surveillance of the microstructures and nonequilibrium phase is demonstrated. Alloys with specific compositions were synthesized with extended solid solutions, stable dispersoids, and specific phase boundaries associated with different heat treatments. Phase stability and mechanical behavior of these nonequilibrium alloys were investigated and compared.

  16. Combined thermodynamic study of nickel-base alloys. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, C. R.; Meschter, P. J.

    1981-02-15

    Achievements during this period are the following: (1) initiation of a high-temperature study of the Ni-Ta system using the galvanic cell technique, (2) emf study of high-temperature thermodynamics in the Ni-Mo system, (3) measured heat capacity data on ordered and disordered Ni/sub 4/Mo, (4) heat capacities of Ni and disordered Ni/sub 3/Fe, and (5) computer correlation of thermodynamic and phase diagram data in binary Ni-base alloys. (MOW)

  17. Plastic strain characterization in austenitic stainless steels and nickel alloys by electron backscatter diffraction

    Science.gov (United States)

    Sáez-Maderuelo, A.; Castro, L.; de Diego, G.

    2011-09-01

    Stress corrosion cracking (SCC) is enhanced by cold work and causes many problems in components of the nuclear power plants. Besides, during manufacturing, installation, welding and service of the material, residual strains can be produced increasing the susceptibility to SCC. For this reason, it is important to characterize the degree of plastic strain due to dislocation accumulation in each crystal. Electron backscatter diffraction (EBSD), in conjunction with scanning electron microscope (SEM), has been a great advance in this field because it enables to estimate the plastic strain in a quick and easy way. Nevertheless, over the last few years, a lot of different mathematical expressions to estimate the plastic strain have appeared in the literature. This situation hinders the election of one of them by a novel scientist in this field. Therefore, in this paper some of the more common expressions used in the calculation of the angular misorientation have been presented and discussed in order to clarify their more important aspects. Then, using one of these expressions (average local misorientation), curves relating misorientation density with known levels of strain will be obtained for an austenitic stainless steel 304L and nickel base alloy 690, which have shown a linear behaviour that is in good agreement with results found in the literature. Finally, using curves obtained in previous steps, levels of plastic strain in a plate of nickel base alloy 600 welded with weld metal 182 were estimated between 8 and 10% for a high temperature mill annealing sample.

  18. X-ray diffraction study of residual elastic stress and microstructure of near-surface layers in nickel-titanium alloy irradiated with low-energy high-current electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Meisner, L.L. [Institute of Strength Physics and Materials Science SB RAS, 2/4 Akademichesky Ave., Tomsk, 634021 (Russian Federation); National Research Tomsk State University, 36 Lenin Ave., Tomsk, 634036 (Russian Federation); Lotkov, A.I. [Institute of Strength Physics and Materials Science SB RAS, 2/4 Akademichesky Ave., Tomsk, 634021 (Russian Federation); Ostapenko, M.G., E-mail: artifakt@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, 2/4 Akademichesky Ave., Tomsk, 634021 (Russian Federation); National Research Tomsk Polytechnic University, 30 Lenin Ave., Tomsk, 634050 (Russian Federation); Gudimova, E.Yu. [Institute of Strength Physics and Materials Science SB RAS, 2/4 Akademichesky Ave., Tomsk, 634021 (Russian Federation)

    2013-09-01

    In the work, we compare quantitative estimates of residual stresses in nickel-titanium (NiTi) alloy surface layers after electron beam treatment. The quantitative estimates to be compared were taken using X-ray diffraction (XRD) techniques with symmetric and asymmetric Bragg diffraction geometries. A method of quantitative X-ray diffraction estimation of residual stresses in materials with gradient changes in microstructure and physical properties, including elastic moduli, is described. It is found that in a NiTi specimen with one side irradiated by a low-energy high-current electron beam, the maximum residual elastic stresses σ ≈550 MPa are localized in the modified surface layer (melted by the electron beam and rapidly quenched), whereas the residual elastic stresses in the underlying layer with initial B2 structure are no greater than ∼100 MPa. It is for this reason that stress-induced B19′ martensite is formed in the material layer beneath the modified layer.

  19. Recovery of aluminium, nickel-copper alloys and salts from spent fluorescent lamps.

    Science.gov (United States)

    Rabah, Mahmoud A

    2004-01-01

    This study explores a combined pyro-hydrometallurgical method to recover pure aluminium, nickel-copper alloy(s), and some valuable salts from spent fluorescent lamps (SFLs). It also examines the safe recycling of clean glass tubes for the fluorescent lamp industry. Spent lamps were decapped under water containing 35% acetone to achieve safe capture of mercury vapour. Cleaned glass tubes, if broken, were cut using a rotating diamond disc to a standard shorter length. Aluminium and copper-nickel alloys in the separated metallic parts were recovered using suitable flux to decrease metal losses going to slag. Operation variables affecting the quality of the products and the extent of recovery with the suggested method were investigated. Results revealed that total loss in the glass tube recycling operation was 2% of the SFLs. Pure aluminium meeting standard specification DIN 1712 was recovered by melting at 800 degrees C under sodium chloride/carbon flux for 20 min. Standard nickel-copper alloys with less than 0.1% tin were prepared by melting at 1250 degrees C using a sodium borate/carbon flux. De-tinning of the molten nickel-copper alloy was carried out using oxygen gas. Tin in the slag as oxide was recovered by reduction using carbon or hydrogen gas at 650-700 degrees C. Different valuable chloride salts were also obtained in good quality. Further research is recommended on the thermodynamics of nickel-copper recovery, yttrium and europium recovery, and process economics.

  20. Carbide Coatings for Nickel Alloys, Graphite and Carbon/Carbon Composites to be used in Fluoride Salt Valves

    Energy Technology Data Exchange (ETDEWEB)

    Nagle, Denis [Johns Hopkins Univ., Baltimore, MD (United States); Zhang, Dajie [Johns Hopkins Univ., Baltimore, MD (United States)

    2015-10-22

    The focus of this research was concerned with developing materials technology that supports the evolution of Generation IV Advanced High Temperature Reactor (AHTR) concepts. Specifically, we investigate refractory carbide coatings for 1) nickel alloys, and 2) commercial carbon-carbon composites (CCCs). Numerous compelling reasons have driven us to focus on carbon and carbide materials. First, unlike metals, the strength and modulus of CCCs increase with rising temperature. Secondly, graphite and carbon composites have been proven effective for resisting highly corrosive fluoride melts such as molten cryolite [Na₃AlF₆] at ~1000°C in aluminum reduction cells. Thirdly, graphite and carbide materials exhibit extraordinary radiation damage tolerance and stability up to 2000°C. Finally, carbides are thermodynamically more stable in liquid fluoride salt than the corresponding metals (i.e. Cr and Zr) found in nickel based alloys.

  1. Influence of Chromium and Molybdenum on the Corrosion of Nickel Based Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, J R; Gray, J; Szmodis, A W; Orme, C A

    2005-08-02

    The addition of chromium and molybdenum to nickel creates alloys with exceptional corrosion resistance in a diverse range of environments. This study examines the complementary roles of Cr and Mo in Ni alloy passivation. Four nickel alloys with varying amounts of chromium and molybdenum were studied in 1 molar salt solutions over a broad pH range. The passive corrosion and breakdown behavior of the alloys suggests that chromium is the primary element influencing general corrosion resistance. The breakdown potential was nearly independent of molybdenum content, while the repassivation potential is strongly dependant on the molybdenum content. This indicates that chromium plays a strong role in maintaining the passivity of the alloy, while molybdenum acts to stabilize the passive film after a localized breakdown event.

  2. Dendritic growth and structure of undercooled nickel base alloys

    Science.gov (United States)

    Flemings, M. C.; Shiohara, Y.

    1988-01-01

    The principal objectives of this overall investigation are to: study means for obtaining high undercooling in levitation melted droplets, and study structures produced upon the solidification of these undercooled specimens. Thermal measurements are made of the undercooling, and of the rapid recalescence, to develop an understanding of the solidification mechanism. Comparison of results is made with the modeling studies. Characterization and metallographic work is done to gain an understanding of the relationship between rapid solidification variables and the structures so produced. In ground based work to date, solidification of undercooled Ni-25 wt percent Sn alloy was observed by high-speed cinematography and the results compared with optical temperature measurements. Also in ground based work, high-speed optical temperature measurements were made of the solidification behavior of levitated metal samples within a transparent glass medium. Two undercooled Ni-Sn alloys were examined. Measurements were carried out on samples at undercoolings up to 330 K. Microstructures of samples produced in ground based work were determined by optical metallography and by SEM, and microsegregation by electron microprobe measurements. A series of flight tests were planned to conduct experiments similar to the ground based experiments. The Space Shuttle Columbia carried an alloy undercooled experiment in the STS 61-C mission in January 1986. A sample of Ni-32.5 wt percent Sn eutectic was melted and solidified under microgravity conditions.

  3. High speed machining of aero-engine alloys

    OpenAIRE

    Ezugwu, E. O.

    2004-01-01

    Materials used in the manufacture of aero-engine components generally comprise of nickel and titanium base alloys. Advanced materials such as aero-engine alloys, structural ceramic and hardened steels provide serious challenges for cutting tool materials during machining due to their unique combinations of properties such as high temperature strength, hardness and chemical wear resistance. These materials are referred to as difficult-to-cut since they pose a greater challenge to manufacturing...

  4. [Effects of Sol-Gel coating on the corrosion resistance of nickel-chronium alloys].

    Science.gov (United States)

    Li, Lei; Zhu, Zhi-Min; Liao, Yun-Mao

    2009-02-01

    To investigate the effects of Sol-Gel coating on the corrosion resistance of nickel-chronium alloys in vitro. The bond strength of coating-substrate interface sintered at different temperatures (300, 400, 500, 600 degrees C) was tested by scratching method. The Sol-Gel coating was analyzed by scanning electron microscope (SEM), and its corrosion resistance was assessed by a static immersion method. The bond strength of coating-substrate interface reaches the peak at 400 degrees C. The Sol -Gel coating can apparently inhibit the release of metal ions and improve the corrosion resistance of nickel-chromium alloy. Sol-Gel coating can evidently improve corrosion resistance of the nickel-chromium alloy, which has great potential in prospective clinical practice.

  5. Spectrophotometric studies and applications for the determination of Ni²+ in zinc-nickel alloy electrolyte.

    Science.gov (United States)

    Qiao, Xiaoping; Li, Helin; Zhao, Wenzhen; Li, Dejun

    2012-09-01

    The absorption properties of zinc-nickel alloy electrolyte were studied by visible spectrophotometer. The results show that the relationship between the absorbance of the zinc-nickel alloy electrolyte and Ni(2+) concentration in the electrolyte obeys Beer's law at 660 nm. In addition, other components except Ni(2+) in the zinc-nickel alloy electrolyte such as zinc chloride, ammonium chloride, potassium chloride and boric acid have no obvious effect on the absorbance of zinc-nickel alloy electrolyte. Based on these properties, a new method is developed to determine Ni(2+) concentration in zinc-nickel alloy electrolyte. Comparing with other methods, this method is simple, direct and accurate. Moreover, the whole testing process does not consume any reagent and dilution, and after testing, the electrolyte samples can be reused without any pollution to the environment. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

  6. An Investigation of the Mechanical Properties of a Weldment of 7% Nickel Alloy Steels

    Directory of Open Access Journals (Sweden)

    Jeong Yeol Park

    2016-11-01

    Full Text Available During the last decade, the demand for natural gas has steadily increased for the prevention of environmental pollution. For this reason, many liquefied natural gas (LNG carriers have been manufactured. Since one of the most important issues in the design of LNG carriers is to guarantee structural safety, the use of low-temperature materials is increasing. Among commonly employed low-temperature materials, nickel steel has many benefits such as good strength and outstanding corrosion resistance. Accordingly, nickel steels are one of the most commonly used low-temperature steels for LNG storage tanks. However, the study of fracture toughness with various welding consumables of 7% nickel alloy steel is insufficient for ensuring the structural safety of LNG storage tanks. Therefore, the aim of this study was to evaluate fracture toughness of several different weldments for 7% nickel alloy steels. The weldment of 7% nickel alloy steel was fabricated by tungsten inert gas (TIG, flux cored arc welding (FCAW, and gas metal arc welding (GMAW. In order to assess the material performance of the weldments at low temperature, fracture toughness such as crack tip opening displacement (CTOD and the absorbed impact energy of weldments were compared with those of 9% nickel steel weldments.

  7. In vivo aging of orthodontic alloys: implications for corrosion potential, nickel release, and biocompatibility.

    Science.gov (United States)

    Eliades, Theodore; Athanasiou, Athanasios E

    2002-06-01

    Despite the large number of studies investigating nickel release from orthodontic stainless steel and nickel-titanium alloys, there is a lack of conclusive evidence with respect to the composition and kinetics of the corrosive products released. The objective of this review is to address the critical issues of corrosion potential and nickel leaching from alloys by investigating the effect of intraoral conditions on the surface reactivity of the materials. After an overview of fundamentals of metallurgical structure of orthodontic alloys, we provide an analysis of corrosion processes occurring in vivo. We present recent evidence suggesting the formation of a proteinaceous biofilm on retrieved orthodontic materials that later undergoes calcification. We illustrate the vastly irrelevant surface structure of in vivo- vs in vitro-aged alloys and discuss the potential implications of this pattern in the reactivity of the materials. Finally, we present a comprehensive review of the issue of nickel release, based on three perspectives: its biologic effects, the methods used for studying its release, and nickel-induced hypersensitivity in orthodontic patients.

  8. Welding of titanium and nickel alloy by combination of explosive welding and spark plasma sintering technologies

    Science.gov (United States)

    Malyutina, Yu. N.; Bataev, A. A.; Mali, V. I.; Anisimov, A. G.; Shevtsova, L. I.

    2015-10-01

    A possibility of titanium and nickel-based alloys composite materials formation using combination of explosive welding and spark plasma sintering technologies was demonstrated in the current research. An employment of interlayer consisting of copper and tantalum thin plates makes possible to eliminate a contact between metallurgical incompatible titanium and nickel that are susceptible to intermetallic compounds formation during their interaction. By the following spark plasma sintering process the bonding has been received between titanium and titanium alloy VT20 through the thin powder layer of pure titanium that is distinguished by low defectiveness and fine dispersive structure.

  9. Initial deposition mechanism of electroless nickel plating on AZ91D magnesium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Song, Y.; Shan, D.; Han, E. [Chinese Academy of Sciences, Environmental Corrosion Center, Inst. of Metal Research, Shenyang (China)

    2006-04-15

    The pretreatment processes and initial deposition mechanism of electroless nickel plating on AZ91D magnesium alloy were investigated by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). The results showed that alkaline cleaning could remove the greases and oils from the substrate surface. Acid etching could wipe off the metal chippings and oxides. The hydrofluoric acid activating process which could improve the adhesion of coating to substrate played a key role in the subsequent process of electroless nickel plating. The nickel coating was deposited preferentially on the primary {alpha} phase and then spread to the eutectic {alpha} phase and {beta} phase. The nickel initially nucleated on the primary {alpha} phase by a replacement reaction, then grew depending on the autocatalysis function of nickel. The coating on the {beta} phase displayed better adhesion than that on the {alpha} phase due to the nails fixing effect. (author)

  10. Corrosion behaviour of austenitic stainless steel, nickel-base alloy and its weldments in aqueous LiBr solutions

    Energy Technology Data Exchange (ETDEWEB)

    Blasco-Tamarit, E.; Igual-Munoz, A.; Garcia Anton, J.; Garcia-Garcia, D. [Departamento de Ingenieria Quimica y Nuclear. E.T.S.I.Industriales, Universidad Politecnica de Valencia, P.O. Box 22012 E-46071 Valencia (Spain)

    2004-07-01

    With the advances in materials production new alloys have been developed, such as High- Alloy Austenitic Stainless Steels and Nickel-base alloys, with high corrosion resistance. These new alloys are finding applications in Lithium Bromide absorption refrigeration systems, because LiBr is a corrosive medium which can cause serious corrosion problems, in spite of its favourable properties as absorbent. The objective of the present work was to study the corrosion resistance of a highly alloyed austenitic stainless steel (UNS N08031) used as base metal, a Nickel-base alloy (UNS N06059) used as its corresponding filler metal, and the weld metal obtained by the Gas Tungsten Arc Welding (GTAW) procedure. The materials have been tested in different LiBr solutions (400 g/l, 700 g/l, 850 g/l and a commercial 850 g/l LiBr heavy brine containing Lithium Chromate as corrosion inhibitor), at 25 deg. C. Open Circuit Potential tests and potentiodynamic anodic polarization curves have been carried out to obtain information about the general electrochemical behaviour of the materials. The polarization curves of all the alloys tested were typical of passivable materials. Pitting corrosion susceptibility has been evaluated by means of cyclic potentiodynamic curves, which provide parameters to analyse re-passivation properties. The galvanic corrosion generated by the electrical contact between the welded and the base material has been estimated from the polarization diagrams according to the Mixed Potential Method. Samples have been etched to study the microstructure by Scanning Electron Microscopy (SEM). The results demonstrate that the pitting resistance of all these materials increases as the LiBr concentration decreases. In general, the presence of chromate tended to shift the pitting potential to more positive values than those obtained in the 850 g/l LiBr solution. (authors)

  11. Application of cast nickel alloys for parts of electronics characterised by special magnetic properties

    Directory of Open Access Journals (Sweden)

    W. UhI

    2008-03-01

    Full Text Available Thc thcorctical part of the study highlights thc origin of thc idca 10 start investigations on alloys of high ~nngnctic pcrmcability.manufactured mainly by cornpanics in ~ h Uc S A and Japan.'Phc said materials arc applicd for various pans of ctcctronics uscd by thc military industry. c.g. sntctlitc antcnnas Tor globalcommunication with suhmarincs. and for rcscarch instmrncnts, c,g. fcrromagnctic corcs. Thcy arc chnr:~clcriscd by vcry high lnnpncticpcrrncability. resistivity and corrosion rcsistancc which makc thcm suitablc for opcrat ion undcr cxtrn-~ryingc onditions.Nickel alloys of high magnctic propcrtics arc usuall y manufactured as roZlcd products. The amhition of t hc authors or this srlldy is Inmanufacture !hem as cast prnducts.Thc pmgram of rcscarch incIudcd characteristic of nickcl alloys wirh ddi t i ons of molybdcnum slid iron sn~isryingt hc ahnvc mc~iito ncdrcquircmcnu. with attcn~ionf ocusscd on thcir application for magnctic parts of satcllitc antcnnns and fcrromngnctic corcs.Moulding and casting tcchnologics wcrc proposcd to bcst suit ~ h pcr occss OF maaufacturc of r hcsc clcmcnrs.Thc rangc of chcmicaI cornpostion was sclcctcd 20 cnsurc thc rcquircd magnctic. mcchnnicnl and anti-corrosive pmpcrtics.A scrics of melts was prcparcd and castings of thc abovc mcnlioncd clclncn1s wcrc mndc. Thc chclnicnl composi~ioii of IEIC alloys wasanalyscd along with thc stnlcturc cxarninations nnd quality asscssmcnt rnadc by ~ h cno n-dcsrructi vc rncthods, Casrings wcrc sitbjcctcd tothc finishing trcatmcnt, followed by tests and cxamina~ionsto cnablc thcir practical application.

  12. Nickel, cobalt and titanium-based alloys – from aircraft vehicles to medical applications - REVIEW

    OpenAIRE

    Milan Jovanović

    2016-01-01

    Since the introduction of nickel, cobalt and titanium-based alloys in the early 1950s, these materials in a relatively short time became backbone materials for the aerospace, energy, chemical industry and even medicine. The combination of excellent mechanical properties, corrosion resistance and bio-compatibility renders these alloys the best material choice for many critical applications. This review describes the results realized through the research in the Department of Materials Science i...

  13. High-strength and high-RRR Al-Ni alloy for aluminum-stabilized superconductor

    CERN Document Server

    Wada, K; Sakamoto, H; Yamamoto, A; Makida, Y

    2000-01-01

    The precipitation type aluminum alloys have excellent performance as the increasing rate in electric resistivity with additives in the precipitation state is considerably low, compared to that of the aluminum alloy with additives in the solid-solution state. It is possible to enhance the mechanical strength without remarkable degradation in residual resistivity ratio (RRR) by increasing content of selected additive elements. Nickel is the suitable additive element because it has very low solubility in aluminum and low increasing rate in electric resistivity, and furthermore, nickel and aluminum form intermetallic compounds which effectively resist the motion of dislocations. First, Al-0.1wt%Ni alloy was developed for the ATLAS thin superconducting solenoid. This alloy achieved high yield strength of 79 MPa (R.T.) and 117 MPa (4.2 K) with high RRR of 490 after cold working of 21% in area reduction. These highly balanced properties could not be achieved with previously developed solid-solution aluminum alloys. ...

  14. Properties of experimental copper-aluminium-nickel alloys for dental post-and-core applications.

    Science.gov (United States)

    Rittapai, Apiwat; Urapepon, Somchai; Kajornchaiyakul, Julathep; Harniratisai, Choltacha

    2014-06-01

    This study aimed to develop a copper-aluminium-nickel alloy which has properties comparable to that of dental alloys used for dental post and core applications with the reasonable cost. Sixteen groups of experimental copper alloys with variants of 3, 6, 9, 12 wt% Al and 0, 2, 4, 6 wt% Ni were prepared and casted. Their properties were tested and evaluated. The data of thermal, physical, and mechanical properties were analyzed using the two-way ANOVA and Tukey's test (α=0.05). The alloy toxicity was evaluated according to the ISO standard. The solidus and liquidus points of experimental alloys ranged from 1023℃ to 1113℃ and increased as the nickel content increased. The highest ultimate tensile strength (595.9 ± 14.2 MPa) was shown in the Cu-12Al-4Ni alloy. The tensile strength was increased as the both elements increased. Alloys with 3-6 wt% Al exhibited a small amount of 0.2% proof strength. Accordingly, the Cu-9Al-2Ni and Cu-9Al-4Ni alloys not only demonstrated an appropriate modulus of elasticity (113.9 ± 8.0 and 122.8 ± 11.3 GPa, respectively), but also had a value of 0.2% proof strength (190.8 ± 4.8 and 198.2 ± 3.4 MPa, respectively), which complied with the ISO standard requirement (>180 MPa). Alloys with the highest contents of nickel (6 wt% Ni) revealed a widespread decolourisation zone (5.0-5.9 mm), which correspondingly produced the largest cell response, equating positive control. The copper alloys fused with 9 wt% Al and 2-4 wt% Ni can be considered for a potential use as dental post and core applications.

  15. Brushing-induced surface roughness of two nickel based alloys and a titanium based alloy: a comparative study - in vitro study.

    Science.gov (United States)

    Acharya, B L Guruprasanna; Nadiger, Ramesh; Shetty, Bharathraj; Gururaj, G; Kumar, K Naveen; Darshan, D D

    2014-06-01

    Alloys with high nickel content have been increasingly used in dentistry. Alloys have high corrosion rates when exposed to chemical or physical forces that are common intra orally. Titanium is the most biocompatible materials for crowns, fixed partial dentures and implants in the present use, but paradoxically the self-protective oxide film on the titanium can be affected by excessive use of the most common preventive agents in dentistry. Therefore, this study is undertaken in order to draw attention toward the potential effect of prophylactic brushing in a saline medium. Forty-five wax patterns in equal dimensions of 10 mm × 10 mm × 2 mm were cast in titanium (Grade II) and nickel-chromium. Of the 45 wax patterns, 15 wax patterns were used for preparing cast titanium samples and 30 wax patterns were used for preparing cast nickel-chromium samples and polished. These samples were divided into three groups of 15 samples each. They are brushed for 48 h each clinically simulating 2 years of brushing in a saline tooth paste medium. The surface roughnesses of the samples were evaluated using profilometer, scanning electron microscopes and energy dispersive spectroscopy. RESULTS were subjected to statistical analysis. The statistical analysis of the Rz and Ra surface roughness values were calculated. Significant difference of surface roughness was present in the titanium samples compared to that of the machine-readable cataloguing and Wirolloy (nickel-chromium) samples after the study. To know the difference in the values of all samples before and after, Student's paired t-test was carried out. RESULTS showed that there is a significant change in the Rz and Ra values of titanium samples. The present findings suggest that, prophylactic brushing with the fluoridated toothpaste have an effect on the surface roughness of titanium and also to a certain extent, on nickel-chromium. Therefore, careful consideration must be given to the selection of the toothbrushes and

  16. The environmentally-assisted cracking behaviour in the transition region of nickel-base alloy/low-alloy steel dissimilar weld joints under simulated BWR conditions

    Energy Technology Data Exchange (ETDEWEB)

    Ritter, S.; Seifert, H.P.; Leber, H.J. [Paul Scherrer Institute, Nuclear Energy and Safety Research Department, Lab for Nuclear Materials, 5232 Villigen PSI (Switzerland)

    2011-07-01

    The stress corrosion cracking (SCC) behaviour perpendicular to the fusion line in the transition region between the Alloy 182 nickel-base weld metal and the adjacent low-alloy reactor pressure vessel (RPV) steel of simulated dissimilar metal weld joints was investigated under boiling water reactor normal water chemistry conditions at different stress intensities and chloride concentrations. A special emphasis was placed to the question whether a fast growing inter-dendritic SCC crack in the highly susceptible Alloy 182 weld metal can easily cross the fusion line and significantly propagate into the adjacent low-alloy RPV steel. Cessation of inter-dendritic stress corrosion crack growth was observed in high-purity or sulphate-containing oxygenated water under periodical partial unloading or constant loading conditions with stress intensity factors below 60 MPa-m{sup 1/2} for those parts of the crack front, which reached the fusion line. In chloride containing water, on the other hand, the inter-dendritic stress corrosion crack in the Alloy 182 weld metal very easily crossed the fusion line and further propagated with a very high growth rate as a transgranular crack into the heat-affected zone and base material of the adjacent low-alloy steel. (authors)

  17. Assessment of special stainless steels and nickel-base alloys for use under offshore conditions

    Energy Technology Data Exchange (ETDEWEB)

    Jasner, M.R. [Krupp VDM GmbH, Duisburg (Germany); Herda, W.R. [Krupp VDM GmbH, Werdohl (Germany)

    1994-12-31

    Major offshore installations are designed for a 25-years` life span and more. To predict the corrosion behavior of various alloys for such a long period results from accelerated laboratory tests have to be verified by suitable field tests. The results from laboratory tests and exposure to natural seawater show that nickel-based alloys such as alloy 59 (UNS N06059) and alloy 31 (UNS N08031) can be employed to most severe conditions. For general applications 6Mo stainless steels with 25% Ni such as alloy 926 (UNS N08926) may be used. If higher strength is required alloy 24 (18 Ni-24.5 Cr-6.2 Mn-4.3 Mo-0.6 Cu-0.45 Mn) is the preferred material.

  18. NASA vane alloy boasts high-temperature strength

    Science.gov (United States)

    Waters, W. J.; Freche, J. C.

    1975-01-01

    The higher inlet-gas temperatures in new aircraft turbine engines make it necessary to use improved superalloys in engine design. Such superalloys are provided by WAZ alloys. NASA has explored the Ni-W-Al system in an attempt to find higher-strength nickel-based alloys for use as stator vane materials. Critical performance goals have been met with the new alloy WAZ-16. With suitable protective coatings, WAZ-16 appears to have considerable potential for high-temperature stator vane applications.

  19. Cytotoxic, allergic and genotoxic activity of a nickel-titanium alloy

    NARCIS (Netherlands)

    Veldhuizen, AG; Sanders, MM; Schakenraad, JM; vanHorn, [No Value

    The nearly equiatomic nickel-titanium (NiTi) alloy is known for its shape memory properties. These properties can be put to excellent use in various biomedical applications, such as wires for orthodontic tooth alignment and osteosynthesis staples. The aim of this study was to evaluate the short-term

  20. Determination of Trace Elements in Nickel Base Alloys by Atomic Absorption Spectrophotometry.

    Science.gov (United States)

    An investigation is described to ascertain whether or not atomic absorption spectrophotometry could be used to determine the concentration of trace ... elements such as silver (Ag), bismuth (Bi), cadmium (Cd), lead (Pb), phosphorus (P), and arsenic (As) in nickel alloys such as Udimet 500 without interference of other constituent elements. (Author)

  1. Effects of surface finishing conditions on the biocompatibility of a nickel-chromium dental casting alloy.

    LENUS (Irish Health Repository)

    McGinley, Emma Louise

    2011-07-01

    To assess the effects of surface finishing condition (polished or alumina particle air abraded) on the biocompatibility of direct and indirect exposure to a nickel-chromium (Ni-Cr) d.Sign®10 dental casting alloy on oral keratinocytes. Biocompatibility was performed by assessing cellular viability and morphology, metabolic activity, cellular toxicity and presence of inflammatory cytokine markers.

  2. Nickel-free Fe-12Mn-0.2Ti alloy steel for cryogenic applications

    Science.gov (United States)

    Hwang, S.; Jin, S.; Morris, J. W., Jr.

    1976-01-01

    A nickel-free Fe-12Mn-0.2Ti alloy steel was investigated for cryogenic applications. The systematic control of the grain size and the microstructural distribution of the retained gamma phase was made through alpha plus gamma heat treatments in combination with mechanical working. Substantial improvements of important low temperature mechanical properties were obtained by these processings.

  3. Separating the strengthening phase in nickel-cobalt alloys doped with tantalum

    Science.gov (United States)

    Shaipov, R. Kh.; Kerimov, E. Yu.; Slyusarenko, E. M.

    2017-02-01

    The hardness values of monophasic (fcc solid solution) and biphasic (fcc solid solution and separated phase) nickel-cobalt alloys doped with tantalum are determined using the Vickers method. Based on the resulting data, a composition-structure-hardness diagram is devised for the Co-Ni-Ta system.

  4. Study made of corrosion resistance of stainless steel and nickel alloys in nuclear reactor superheaters

    Science.gov (United States)

    Greenberg, S.; Hart, R. K.; Lee, R. H.; Ruther, W. E.; Schlueter, R. R.

    1967-01-01

    Experiments performed under conditions found in nuclear reactor superheaters determine the corrosion rate of stainless steel and nickel alloys used in them. Electropolishing was the primary surface treatment before the corrosion test. Corrosion is determined by weight loss of specimens after defilming.

  5. Carbon induced metal dusting of iron-nickel-chromium alloy surfaces : a scanning auger microscopy study

    NARCIS (Netherlands)

    Palasantzas, G; DeHosson, JTM

    2004-01-01

    In this work, we present an investigation on metal dusting of iron-nickel-chromium (Fe-Ni-Cr) alloy surfaces using scanning auger microscopy. It is shown that the formation of surface Cr-oxide and the surface finish condition can strongly influence and interrupt this catastrophic phenomenon. The

  6. Corrosion Behavior of Amorphous Nickel-Valve Metal Alloys in Boiling Concentrated Nitric and Hydrochloric Acids

    OpenAIRE

    Kazuo, SHIMAMURA; Asahi, Kawashima; Katsuhiko, Asami; Koji, Hashimoto; Mitsui Engineering & Shipbuilding Co., Ltd.; The Research Institute for Iron, Steel and Other Metals

    1986-01-01

    The corrosion behavior of amorphous nickel-base alloys containing titanium, zirconium, niobium, tantalum and/or phosphorus in boiling 9 N HNO_3 solutions with and without Cr^ ion and in a boiling 6 N HCl solution was investigated. In boiling 9 N HNO_3 solutions alloys containing 20 at% or more tantalum were immune to corrosion, maintaining the metallic luster, and Ni-40~60Nb alloys showed low corrosion rates of the order of μm/year. In the boiling 6 N HCl solution only tantalum-containing all...

  7. Corrosion Behavior of Amorphous Nickel-Valve Metal Alloys in Boiling Concentrated Nitric and Hydrochloric Acids

    OpenAIRE

    Shimamura, Kazuo; Kawashima, Asahi; ASAMI, Katsuhiko; Hashimoto, Koji

    1986-01-01

    The corrosion behavior of amorphous nickel-base alloys containing titanium, zirconium, niobium, tantalum and/or phosphorus in boiling 9 N HNO_3 solutions with and without Cr^ ion and in a boiling 6 N HCl solution was investigated. In boiling 9 N HNO_3 solutions alloys containing 20 at% or more tantalum were immune to corrosion, maintaining the metallic luster, and Ni-40?60Nb alloys showed low corrosion rates of the order of μm/year. In the boiling 6 N HCl solution only tantalum-containing all...

  8. Crystallographic Orientation Dependence of Corrosion Behavior of a Single Crystal Nickel-Based Alloy

    Science.gov (United States)

    Zhang, L. N.; Ojo, O. A.

    2018-01-01

    Crystallographic orientation dependence of corrosion behavior of a nickel-based single crystal alloy IN738 was studied. Potentiodynamic polarization and electrochemical impedance spectroscopy show that corrosion performance of the single crystal alloy varies with crystallographic orientation. The dependence of passivation behavior on crystallographic orientation is influenced by environmental concentration. Potentiostatic polarization, scanning probe microscopy, and X-ray photoelectron spectroscopy were performed to understand the variation in passivation of different crystallographic orientations. The crystallographic orientation dependence of corrosion performance of the alloy can be explained by the difference of passive films in terms of chemical compositions, compactness, and porosity properties, as well as surface roughness.

  9. Experimental study on dieless drawing of Nickel-Titanium alloy.

    Science.gov (United States)

    Twohig, E; Tiernan, P; Tofail, S A M

    2012-04-01

    The effect of a dieless drawing process on commercial grade Nickel-Titanium rods, of 5 mm diameter, was investigated by varying the established critical process parameters of temperature, cooling rate, drawing velocity, and heating/cooling velocity. The rods were successfully dieless drawn with a maximum steady state reduction in cross-sectional area of 54%. The thermal and mechanical loading profiles of the rod during processing, and the resulting changes in microstructure and hardness, have been investigated. Uniform levels of stress and strain resulted in uniform reduction of the rod cross-sectional area. The grain structure was highly deformed in the drawing direction and increased porosity was observed as a result of the process. The longitudinal section hardness of the rod was significantly reduced as a result of the dieless drawing process. Any failures that arose were due to discontinuities within the material microstructure caused by a high necking rate, shorter exposure time to the process temperature and low heating and cooling rates. A uniform oxidation layer was observed on the surface of the processed rods as a result of processing in atmospheric conditions. This oxidation layer has the potential to aid in the lubrication of subsequent cold working operations of the dieless drawn rods. Coupling the thermomechanical effects of the dieless drawing process with a cold drawing processing step has the potential to produce a NiTi wire in fewer passes, and therefore at a reduced cost. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. An invitro analysis of elemental release and cytotoxicity of recast nickel-chromium dental casting alloys.

    Science.gov (United States)

    Reddy, Nagam Raja; Abraham, Anandapandian Ponsekar; Murugesan, Krishnan; Matsa, Vasanthakumar

    2011-06-01

    Recasting of the casting alloys affects the composition and elemental release which may have cytotoxic effect different from the pure alloy in the surrounding tissues. An Invitro study was conducted to investigate the elemental release and their cytotoxic effects from commercially available Ni-Cr dental casting alloys, commonly used for fabricating fixed partial dentures. Three Ni-Cr alloys [Wiron 99(A), Ceramet (B), and Hi Nickel CB (C)] were tested. Alloy specimens (disks 3 × 5 mm) were casted and grouped as follows: Group I (A(1)/B(1)/C(1)): 100% pure alloy; Group II (A(2)/B(2)/C(2)): 50% new with 50% recast; and Group III (A(3)/B(3)/C(3)): 100% recast. Disks of each alloy type from each group were transferred to Dulbecco's modified eagle medium and left for 3 days at 37°C in an atmosphere of 5% CO(2). Ni, Cr, Co, Cu and Mo elemental release from metal alloys into culture medium was investigated using Inductively Coupled Plasma Mass Spectrometry. Cytotoxicity was tested using mouse fibroblast cells and MTT Assay. Controls consisted of 6 wells containing cells with no alloy specimens. Data were analyzed by two-way analysis of variance followed by t-test. The total amount of elements released in parts per billion for various casting groups were Group I, A(1)-6.572, B(1)-6.732, C(1)-8.407; Group II, A(2)-22.046, B(2)-26.450, C(2)-29.189; Group III, A(3)-84.554, B(3)-88.359, C(3)-92.264. More amounts of elements were released in Hi Nickel CB than Ceramet and Wiron 99 in all the three test groups. Percentage of viable cells from MTT analysis were Group I, A(1)-62.342, B(1)-61.322 C(1)-60.593, Group II, A(2)-58.699, B(2)-56.494, C(2)-52.688, Group III, A(3)-53.101, B(3)-52.195, C(3)-47.586. The viable cells present in the culture media were more in Wiron 99 than Ceramet and Hi Nickel CB. Elemental release increased with amount of recast alloy. Amongst the three alloys tested Hi Nickel CB had significantly higher elements released compared to Ceramet and Wiron 99

  11. Platinum-nickel alloy nanoparticles supported on carbon for 3-pentanone hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Lihua, E-mail: lihuazhu@stu.xmu.edu.cn [School of Metallurgy and Chemical Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, Jiang Xi (China); Department of Chemical and Biochemical Engineering, National Engineering Laboratory for Green Productions of Alcohols-Ethers-Esters, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China); Zheng, Tuo; Yu, Changlin [School of Metallurgy and Chemical Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, Jiang Xi (China); Zheng, Jinbao [Department of Chemical and Biochemical Engineering, National Engineering Laboratory for Green Productions of Alcohols-Ethers-Esters, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China); Tang, Zhenbiao [School of Metallurgy and Chemical Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, Jiang Xi (China); Zhang, Nuowei [Department of Chemical and Biochemical Engineering, National Engineering Laboratory for Green Productions of Alcohols-Ethers-Esters, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China); Shu, Qing [School of Metallurgy and Chemical Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, Jiang Xi (China); Chen, Bing H., E-mail: chenbh@xmu.edu.cn [Department of Chemical and Biochemical Engineering, National Engineering Laboratory for Green Productions of Alcohols-Ethers-Esters, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China)

    2017-07-01

    Highlights: • The PtNi/Ni(OH){sub 2}/C catalyst was successfully synthesized at room temperature. • PtNi alloy/C was obtained after PtNi/Ni(OH){sub 2}/C reduced in hydrogen at 300 °C. • Nanostructures of the PtNi catalysts were characterized by numerous techniques. • PtNi alloy/C exhibited high catalytic activity for 3-pentanone hydrogenation. - Abstract: In this work, we prepared the Ni/Ni(OH){sub 2}/C sample at room temperature by hydrazine hydrate reducing method. The galvanic replacement reaction method was applied to deposit platinum on the Ni/Ni(OH){sub 2} nanoparticles, to prepare the PtNi/Ni(OH){sub 2}/C catalyst. The catalyst of platinum-nickel alloy nanoparticles supported on carbon (signed as PtNi/C) was obtained by the thermal treatment of PtNi/Ni(OH){sub 2}/C in flowing hydrogen at 300 °C for 2 h. The size, nanostructure, surface properties, Pt and Ni chemical states of the PtNi/C catalyst were analyzed using powder X-ray diffraction (XRD), transmission electron microscope (TEM) and high resolution transmission electron microscope (HRTEM), high-angle annular dark-field scanning TEM (HAADF-STEM) and elemental energy dispersive X-ray spectroscopy (EDS) line scanning, X-ray photoelectron spectroscopy (XPS) and high-sensitivity low-energy ion scattering spectroscopy (HS-LEIS) techniques. The as-synthesized PtNi/C catalyst showed enhanced catalytic performance relative to the Ni/Ni(OH){sub 2}/C, Ni/C, Pt/C and PtNi/Ni(OH){sub 2}/C catalysts for 3-pentanone hydrogenation due to electron synergistic effect between Pt and Ni species in the PtNi/C catalyst. The PtNi/C catalyst also had exceling stability, with industrial application value.

  12. Standard specification for Nickel-Chromium-Iron alloys (UNS N06600, N06601, N06603, N06690, N06693, N06025, N06045, and N06696), Nikel-Chromium-Cobalt-Molybdenum alloy (UNS N06617), and Nickel-Iron-Chromium-Tungsten alloy (UNS N06674) seamless pipe and tube

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    Standard specification for Nickel-Chromium-Iron alloys (UNS N06600, N06601, N06603, N06690, N06693, N06025, N06045, and N06696), Nikel-Chromium-Cobalt-Molybdenum alloy (UNS N06617), and Nickel-Iron-Chromium-Tungsten alloy (UNS N06674) seamless pipe and tube

  13. In situ corrosion testing of various nickel alloys at Måbjerg waste incineration plant

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Hansson, A. N.; Jensen, S. A.

    2013-01-01

    The majority of waste in Denmark is disposed via waste to energy (WTE) incineration plants which are fabricated from carbon steel. However, due to the increasing corrosiveness of waste over the years, more corrosion resistant alloys are required. In Denmark, Inconel 625 (UNSN06625) is the weld...... overlay material currently being used to give improved corrosion resistance. In order to assess the use of alternative nickel alloys, test panels have been manufactured and inserted into Måbjerg waste incineration plant. Inconel 625 as a 50% weld overlay, two layered weld overlay and as a spiral weld....... The composition of the deposits from the exposed waterwall panels was also analysed each time sections were removed. This paper will compare the various nickel alloys in the two areas and assess the results of the long‐term testing project....

  14. The effect of nickel addition on antimicrobial, physical, and mechanical properties of copper-nickel alloy against suspensions of Escherichia coli

    Science.gov (United States)

    Nurhayani, Dinni; Korda, Akhmad A.

    2015-09-01

    Escherichia coli (E. coli) infection can cause serious illness. Humans can be infected by E. coli via contact with the contaminated food and water. Copper and copper alloys were known for their antimicrobial properties and were applied in several healthcare setting as antimicrobial material. However, the people preference in the appearance of stainless steel and aluminum contribute to the low application of copper and its alloy. In this study, the mechanical, physical, and antibacterial properties of copper and copper-nickel alloy compared with stainless steel 304 were tested. The antibacterial activity of stainless steel, copper, and copper-nickel alloy was evaluated by inoculating 7.5 × 106 - 2.5 × 107 CFU/ml suspensions of E. coli. The bacterial colonies were investigated after 0-4 hour incubation at 37°C. The result showed that on the observation time, copper and copper-nickel (Cu-Ni) alloys have antibacterial activity while the bacteria in stainless steel remain existed. The appearance (color / shade) of Cu-Ni alloys in some composition is silvery which is stainless steel-like. For the mechanical properties, copper-nickel alloys have lower hardness than stainless steel (SS 304). This research proved that copper-nickel alloys have the ability to reduce the amount of E. col colonies. The copper content may affect the antibacterial activity but not directly linked. Cu-Ni alloys also have the appearance and mechanical properties that quite similar compared to SS304. Therefore, Cu-Ni alloys have the potential to be applied as substitution or complementary material of SS304 in various applications for preventing the bacterial contamination especially E. coli.

  15. Specification and qualification of welding procedures for metallic materials : welding procedure test : part 1 : arc and gas welding of steels and arc welding of nickel and nickel alloys : technical corrigendum 1

    CERN Document Server

    International Organization for Standardization. Geneva

    2005-01-01

    Specification and qualification of welding procedures for metallic materials : welding procedure test : part 1 : arc and gas welding of steels and arc welding of nickel and nickel alloys : technical corrigendum 1

  16. Effect of dry cryogenic treatment on Vickers hardness and wear resistance of new martensitic shape memory nickel-titanium alloy

    National Research Council Canada - National Science Library

    Vinothkumar, Thilla Sekar; Kandaswamy, Deivanayagam; Prabhakaran, Gopalakrishnan; Rajadurai, Arunachalam

    2015-01-01

    The aim of this study is to investigate the role of dry cryogenic treatment (CT) temperature and time on the Vickers hardness and wear resistance of new martensitic shape memory (SM) nickel-titanium (NiTi) alloy...

  17. Bending properties of a new nickel-titanium alloy with a lower percent by weight of nickel.

    Science.gov (United States)

    Testarelli, Luca; Plotino, Gianluca; Al-Sudani, Dina; Vincenzi, Valentina; Giansiracusa, Alessio; Grande, Nicola M; Gambarini, Gianluca

    2011-09-01

    The aim of the present study was to evaluate the bending properties of Hyflex instruments, which exhibit a lower percent in weight of nickel (52 Ni %wt) and compare them with other commercially available nickel-titanium (NiTi) rotary instruments. Ten instruments with tip size 25, 0.06 taper of each of the following NiTi rotary instrumentation techniques were selected for the study: Hyflex, EndoSequence, ProFile, Hero, and Flexmasters. All instruments from each group were tested for stiffness by comparing their bending moment when they attained a 45-degree bend. Experimental procedures strictly followed testing methodology described in ISO 3630-1. All data were recorded and subjected to statistical evaluation by using analysis of variance test. Statistical significance was set at P Hyflex files were found to be the most flexible instruments, with a significant difference (P .05). Results of the present study have illustrated an increased flexibility of the new NiTi alloy over conventional NiTi alloy, and they highlight the potential of the new manufacturing process. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  18. Effect of sulfur on the protective layers on alloys 600 and 690 in low and high temperature environments

    Energy Technology Data Exchange (ETDEWEB)

    Combrade, P.; Foucault, M.; Vancon, D. (Unirec, 42 - Firminy (FR)); Marcus, P.; Grimal, J.M. (Ecole Nationale Superieure de Chimie, 75 - Paris (FR)); Gelpi, A. (Societe Franco-Americaine de Constructions Atomiques (Framatome), 92 - Courbevoie (FR))

    The effect of the presence of sulfide dissolved in the environment on the dissolution and film repair was studied on alloy 600, alloy 690 and nickel exposed to neutral and caustic deaerated solutions at 290{sup 0}C. Comparison with the effect of adsorbed sulfur on the dissolution and film built up on high purity alloy 600 and nickel in acidic solutions at room temperature shows strong analogies. In both cases the beneficial effect of chromium is clearly shown and this is consistent with the better behaviour of alloy with increased chromium content such as alloy 690.

  19. Evaluation and comparison of shear bond strength of porcelain to a beryllium-free alloy of nickel-chromium, nickel and beryllium free alloy of cobalt-chromium, and titanium: An in vitro study.

    Science.gov (United States)

    Singh, Ananya; Ramachandra, Keerthi; Devarhubli, Achut R

    2017-01-01

    The aim of this study was to evaluate and compare the shear bond strength of porcelain to the alloys of nickel-chromium (Ni-Cr), cobalt-chromium (Co-Cr), and titanium. A total of 40 samples (25 mm × 3 mm × 0.5 mm) were fabricated using smooth casting wax and cast using Ni-Cr, Co-Cr, and titanium alloys followed by porcelain buildup. The samples were divided into four groups with each group containing 10 samples (Group A1-10: sandblasted Ni-Cr alloy, Group B1-10: sandblasted Co-Cr alloy, Group C1-10: nonsandblasted titanium alloy, and Group D1-10: sandblasted titanium alloy). Shear bond strength was measured using a Universal Testing Machine. ANOVA test and Tukey's honestly significance difference post hoc test for multiple comparisons. The mean shear bond strength values for these groups were 22.8960, 27.4400, 13.2560, and 25.3440 MPa, respectively, with sandblasted Co-Cr alloy having the highest and nonsandblasted titanium alloy having the lowest value. It could be concluded that newer nickel and beryllium free Co-Cr alloys and titanium alloys with improved strength to weight ratio could prove to be good alternatives to the conventional nickel-based alloys when biocompatibility was a concern.

  20. [The effect of hydrogen peroxide on the electrochemical corrosion properties and metal ions release of nickel-chromium dental alloys].

    Science.gov (United States)

    Wang, Jue; Qiao, Guang-yan

    2013-04-01

    To investigate the effect of hydrogen peroxide on the electrochemical corrosion and metal ions release of nickel-chromium dental alloys. The corrosion resistance of nickel-chromium dental alloys was compared by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curve (PD) methods in artificial saliva after immersed in different concentrations of hydrogen peroxide for 112 h. The metal ions released from nickel-chromium dental alloys to the artificial saliva were detected after electrochemical measurements using inductively coupled plasma mass spectrometry (ICP-MS). The data was statistically analyzed by analysis of variance (ANOVA) using SPSS 13.0 software package. The electrochemical experiment showed that the sequence of polarization resistance in equivalent circuit (Rct), corrosion potential (Ecorr), pitting breakdown potential (Eb), and the difference between Ecorr and Eb representing the "pseudo-passivation" (δE) of nickel-chromium alloys in artificial saliva was 30% corrosion resistance of nickel-chromium dental alloys decrease after immersed in different concentrations of hydrogen peroxide for 112 h. Nickel-chromium dental alloys are more prone to corrosion in the artificial saliva with the concentration of hydrogen peroxide increased, and more metal ions are released in the artificial saliva.

  1. Localized corrosion of molybdenum-bearing nickel alloys in chloride solutions

    Energy Technology Data Exchange (ETDEWEB)

    Postlethwaite, J.; Scoular, R.J.; Dobbin, M.H.

    1988-04-01

    Electrochemical and immersion tests have been applied to a study of the localized corrosion resistance of two molybdenum-bearing nickel alloys. Alloys C-276 and 6y25, in neutral chloride solutions in the temperature range of 25 to 200 C as part of the container materials evaluation screening tests for the Canadian Nuclear Fuel Waste Management Program. Cyclic polarization studies show that the passivation breakdown potentials move rapidly to more active values with increasing temperatures, indicating a reduced resistance to localized corrosion. The results of immersion tests show that both alloys do suffer crevice corrosion in neutral aerated sodium chloride solutions at elevated temperatures, but that in both cases there is a limiting temperature > 100C, below which, the alloys are not attacked, regardless of the chloride concentration.

  2. Study of biocompatibility of medical grade high nitrogen nickel-free austenitic stainless steel in vitro.

    Science.gov (United States)

    Li, Menghua; Yin, Tieying; Wang, Yazhou; Du, Feifei; Zou, Xingzheng; Gregersen, Hans; Wang, Guixue

    2014-10-01

    Adverse effects of nickel ions being released into the living organism have resulted in development of high nitrogen nickel-free austenitic stainless steels for medical applications. Nitrogen not only replaces nickel for austenitic structure stability but also improves steel properties. The cell cytocompatibility, blood compatibility and cell response of high nitrogen nickel-free austenitic stainless steel were studied in vitro. The mechanical properties and microstructure of this stainless steel were compared to the currently used 316L stainless steel. It was shown that the new steel material had comparable basic mechanical properties to 316L stainless steel and preserved the single austenite organization. The cell toxicity test showed no significant toxic side effects for MC3T3-E1 cells compared to nitinol alloy. Cell adhesion testing showed that the number of MC3T3-E1 cells was more than that on nitinol alloy and the cells grew in good condition. The hemolysis rate was lower than the national standard of 5% without influence on platelets. The total intracellular protein content and ALP activity and quantification of mineralization showed good cell response. We conclude that the high nitrogen nickel-free austenitic stainless steel is a promising new biomedical material for coronary stent development. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. The applications and research progresses of nickel-titanium shape memory alloy in reconstructive surgery.

    Science.gov (United States)

    Li, Qiang; Zeng, Yanjun; Tang, Xiaoying

    2010-06-01

    In spite of some good successes and excellent researches of nickel-titanium shape memory alloy (NiTi-SMA) in reconstructive surgery, there are still serious limitations to the clinical applications of NiTi alloy today. The potential leakage of elements and ions could be toxic to cells, tissues and organs. This review discussed the properties, clinical applications, corrosion performance, biocompatibility, the possible preventive measures to improve corrosion resistance by surface/structure modifications and the long-term challenges of using SMAs.

  4. The Solidification Velocity of Undercooled Nickel and Titanium Alloys with Dilute Solute

    Science.gov (United States)

    Algoso, Paul R.; Altgilbers, A. S.; Hofmeister, William H.; Bayuzick, Robert J.

    2003-01-01

    The study of solidification velocity is important for two reasons. First, understanding the manner in which the degree of undercooling of the liquid and solidification velocity affect the microstructure of the solid is fundamental. Second, there is disagreement between theoretical predictions of the relationship between undercooling and solidification velocity and experimental results. Thus, the objective of this research is to accurately and systematically quantify the solidification velocity as a function of undercooling for dilute nickel-and titanium-based alloys. The alloys chosen for study cover a wide range of equilibrium partition coefficients, and the results are compared to current theory.

  5. Crack growth rates of nickel alloy welds in a PWR environment.

    Energy Technology Data Exchange (ETDEWEB)

    Alexandreanu, B.; Chopra, O. K.; Shack, W. J.; Energy Technology

    2006-05-31

    In light water reactors (LWRs), vessel internal components made of nickel-base alloys are susceptible to environmentally assisted cracking. A better understanding of the causes and mechanisms of this cracking may permit less conservative estimates of damage accumulation and requirements on inspection intervals. A program is being conducted at Argonne National Laboratory to evaluate the resistance of Ni alloys and their welds to environmentally assisted cracking in simulated LWR coolant environments. This report presents crack growth rate (CGR) results for Alloy 182 shielded-metal-arc weld metal in a simulated pressurized water reactor (PWR) environment at 320 C. Crack growth tests were conducted on 1-T compact tension specimens with different weld orientations from both double-J and deep-groove welds. The results indicate little or no environmental enhancement of fatigue CGRs of Alloy 182 weld metal in the PWR environment. The CGRs of Alloy 182 in the PWR environment are a factor of {approx}5 higher than those of Alloy 600 in air under the same loading conditions. The stress corrosion cracking for the Alloy 182 weld is close to the average behavior of Alloy 600 in the PWR environment. The weld orientation was found to have a profound effect on the magnitude of crack growth: cracking was found to propagate faster along the dendrites than across them. The existing CGR data for Ni-alloy weld metals have been compiled and evaluated to establish the effects of key material, loading, and environmental parameters on CGRs in PWR environments. The results from the present study are compared with the existing CGR data for Ni-alloy welds to determine the relative susceptibility of the specific Ni-alloy weld to environmentally enhanced cracking.

  6. Antibacterial effect of nickel-titanium alloy owing to nickel ion release

    Science.gov (United States)

    Ohtsu, Naofumi; Suginishi, Sachie; Hirano, Mitsuhiro

    2017-05-01

    This paper demonstrates that a NiTi shape memory alloy demonstrates antibacterial effect owing to the release of Ni ions from the alloy itself. Moreover, non-cytotoxic NiTi alloy with antibacterial properties can be prepared by simple post-heat treatment. We demonstrated that applying Escherichia coli to a NiTi surface resulted in 40% reduction in the number of cells following a 4 h incubation in an ambient atmosphere. When the alloy was heated at 450 °C in air, the antibacterial effect was slightly reduced but the cytotoxicity was drastically reduced. This result indicates that the production of an antibacterial NiTi alloy (without cytotoxic effects) is feasible with an appropriate surface modification. We further revealed that the appropriate Ni ion concentration for both antibacterial effect and biosafety was in the range from 0.05 mg L-1 to 3 mg L-1. Our novel finding represents a new and unique strategy for improving the antibacterial performance of NiTi alloy.

  7. Static and dynamic crack toughness of brazed joints of Inconel 718 nickel-base alloy

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, B.Z. (Technion-Israel Inst. of Tech., Haifa); Steffens, H.D.; Englehart, A.H.; Wielage, B.

    1979-10-01

    The crack toughness of brazed joints of Inconel 718 nickel-base alloy was investigated at different strain rates. The brazing filler metal used was BNi5. The results were compared with those obtained on specimens made of the base material. The brazed joints were heat-treated after the brazing process in order to achieve a desirable distribution of the brittle phases in the joint.

  8. Dislocation Climb Sources Activated by 1 MeV Electron Irradiation of Copper-Nickel Alloys

    DEFF Research Database (Denmark)

    Barlow, P.; Leffers, Torben

    1977-01-01

    Climb sources emitting dislocation loops are observed in Cu-Ni alloys during irradiation with 1 MeV electrons in a high voltage electron microscope. High source densities are found in alloys containing 5, 10 and 20% Ni, but sources are also observed in alloys containing 1 and 2% Ni. The range of ...

  9. Corrosion investigation of multilayered ceramics and experimental nickel alloys in SCWO process environments

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, K.M.; Mizia, R.

    1995-02-01

    A corrosion investigation was done at MODAR, Inc., using a supercritical water oxidation (SCWO) vessel reactor. Several types of multilayered ceramic rings and experimental nickel alloy coupons were exposed to a chlorinated cutting oil TrimSol, in the SCWO process. A corrosion casing was designed and mounted in the vessel reactor with precautions to minimize chances of degrading the integrity of the pressure vessel. Fifteen of the ceramic coated rings were stacked vertically in the casing at one time for each test. There was a total of 36 rings. The rings were in groupings of three rings that formed five sections. Each section saw a different SCWO environment, ranging from 650 to 300{degrees}C. The metal coupons were mounted on horizontal threaded holders welded to a vertical rod attached to the casing cover in order to hang down the middle of the casing. The experimental nickel alloys performed better than the baseline nickel alloys. A titania multilayered ceramic system sprayed onto a titanium ring remained intact after 120-180 hours of exposure. This is the longest time any coating system has withstood such an environment without significant loss.

  10. Corrosion of high temperature alloys in solar salt at 400, 500, and 680ÀC.

    Energy Technology Data Exchange (ETDEWEB)

    Kruizenga, Alan Michael; Gill, David Dennis; LaFord, Marianne Elizabeth

    2013-09-01

    Corrosion tests at 400, 500, and 680ÀC were performed using four high temperature alloys; 347SS, 321SS In625, and HA230. Molten salt chemistry was monitored over time through analysis of nitrite, carbonate, and dissolved metals. Metallography was performed on alloys at 500 and 680ÀC, due to the relatively thin oxide scale observed at 400ÀC. At 500ÀC, corrosion of iron based alloys took the form of chromium depletion and iron oxides, while nickel based alloys also had chromium depletion and formation of NiO. Chromium was detected in relatively low concentrations at this temperature. At 680ÀC, significant surface corrosion occurred with metal losses greater than 450microns/year after 1025hours of exposure. Iron based alloys formed complex iron, sodium, and chromium oxides. Some data suggests grain boundary chromium depletion of 321SS. Nickel alloys formed NiO and metallic nickel corrosion morphologies, with HA230 displaying significant internal oxidation in the form of chromia. Nickel alloys both exhibited worse corrosion than iron based alloys likely due to preferential dissolution of chromium, molybdenum, and tungsten.

  11. In vitro Assessment of Clasps of Cobalt-Chromium and Nickel-titanium Alloys in Removable Prosthesis.

    Science.gov (United States)

    Kola, Mohammed Zaheer; Raghav, Deepti; Kumar, Prince; Alqahtani, Fawaz; Murayshed, Mohammed S; Bhagat, Tushar Vithal

    2016-03-01

    It has been since a long time that the use of base-metal alloys has significantly increased in the area of prosthetic science. One of the factors contributing for the increasing use of base-metal alloys is the increasing and high cost factor of noble metals. Although numerous materials have been tried since the recent past, Cobalt-Chromium (CoCr) alloys still form the most commonly used ones because of the numerous advantages they offer. Titanium alloys are also significantly being used in this field because of their high resistance strength and high corrosion resistance. Therefore, we aimed to evaluate the flexure strength and fatigue resistance of clasps made up of CoCr alloys and Nickel-titanium (NiTi) alloys. We evaluated the retentive forces of CoCr and NiTi clasps two different sizes engaging retentive undercuts of different depths (0.25 and 0.50 mm). Mandibluar second premolar was prepared to frame the prosthesis for missing mandibular first and second molar. A total of 50 clasps were included in the study out of which 30 were NiTi clasps and 30 CoCr clasps. We evaluated the loading of the force at the rate of half Newton(N)/second at the central part of the specimen until fracturing of the specimen occurred and finally measurement of the modulus of elasticity was also done. Statistical analysis was carried out; unpaired "t" test was used for evaluating the level of significance. The mean load needed for CoCr clasps was 0.7450 and for NiTi clasp was 0.6140 Kgf for producing a deflection of 0.25 mm. As far as flexibility is concerned, more value was seen in NiTi group than CoCr group. For deflecting the clasp up to 0.50 mm, the mean load needed for CoCr clasps was 1.4102 and for NiTi clasp was 0.8260 Kgf. The results were statistically significant. While measuring the flexibility, more value (p alloy clasps had mean flexural strength of 1640 MPa and modulus of elasticity of 32 GPa. For producing deflection of 0.25 and 0.50 mm, the mean loading force was

  12. [Effect of recasting on the thickness of metal-ceramic interface of nickel-chromium and cobalt-chromium alloys].

    Science.gov (United States)

    2008-05-01

    This research was done to establish recasting effects of nickel-chromium and cobalt-chromium alloys on the thickness of their metal-ceramic interface in making fixed partial dentures. Metal-ceramic interface determines their functional integrity and prevents damages on ceramics during mastication. Investigation of metal-ceramic samples is supposed to show if base metal alloys for metal-ceramics are successfully recycled without any risk of reduction of metal-ceramic interface thickness. The research was performed as an experimental study. Per six metal-ceramic samples of nickel-chromium alloy (Wiron99) and cobalt-chromium alloy (Wirobond C) were made each. Alloy residues were recycled through twelve casting generations with the addition of 50% of new alloy on the occasion of every recasting. Analysis Energy Dispersive X-ray (EDX) (Oxford Instruments) and Scanning Electon Microscop (SEM) analysis (JEOL) were used to determine thickness of metal-ceramic interface together with PC Software for quantification of visual informations (KVI POPOVAC). Results of this research introduced significant differences between thickness of metal-ceramic interface in every examined recycle generation. Recasting had negative effect on thickness of metal-ceramic interface of the examined alloys. This research showed almost linear reduction of elastic modulus up to the 12th generation of recycling. Recasting of nickel-chromium and cobalt-chromium alloys is not recommended because of reduced thickness of metal-ceramic interface of these alloys. Instead of recycling, the alloy residues should be returned to the manufacturers.

  13. Nickel based alloys as electrocatalysts for oxygen evolution from alkaline solutions. [Metal--air batteries

    Energy Technology Data Exchange (ETDEWEB)

    Lu, P.W.T.; Srinivasan, S.

    1977-01-01

    The slowness of the oxygen evolution reaction is one of the main reasons for significant energy losses in water electrolysis cells and secondary air--metal batteries. To date, data on the kinetics of this reaction on alloys and intermetallic compounds are sparse. In this work, mechanically polished alloys of nickel with Ir, Ru or W and Ni--Ti intermetallic compounds were studied as oxygen electrodes. Since the oxygen evolution reaction always takes place on oxide-film covered surfaces, the nature of oxide films formed on these alloys were investigated using cyclic voltametric techniques. Steady-state potentiostatic and slow potentiodynamic (at 0.1 mV/s) methods were employed to obtain the electrode kinetic parameters for the oxygen evolution reaction in 30 wt. percent KOH at 80/sup 0/C, the conditions normally used in water electrolysis cells. The peaks for the formation or reduction of oxygen-containing layers appearing on the pure metals are not always found on the alloys. The maximum decreases in oxygen overpotential at an apparent current density of 20 mA cm/sup -2/ (as compared with that on Ni) were found for the alloys of 50Ni--50Ir and 75Ni--25Ru and the intermetallic compound Ni/sub 3/Ti, these decreases being about 40, 30, and 20 mV, respectively. On the long-term polarization in the potential region of oxygen evolution, the oxygen-containing layers on Ni--Ir or Ni--Ru alloys are essentially composed of nickel oxides instead of true mixed oxide films of two components. The present work confirms that, possibly because of coverage by oxide films, there is no direct dependence of the electrocatalytic activities of the alloys on their electronic properties. 11 figures, 1 table.

  14. Electrochemical preparation of aluminium-nickel alloys by under-potential deposition in molten fluorides

    Energy Technology Data Exchange (ETDEWEB)

    Gibilaro, M. [Laboratoire de Genie Chimique UMR 5503, Departement Procedes Electrochimiques, Universite Paul Sabatier, 31062 Toulouse Cedex 9 (France); Massot, L. [Laboratoire de Genie Chimique UMR 5503, Departement Procedes Electrochimiques, Universite Paul Sabatier, 31062 Toulouse Cedex 9 (France)], E-mail: massot@chimie.ups-tlse.fr; Chamelot, P.; Taxil, P. [Laboratoire de Genie Chimique UMR 5503, Departement Procedes Electrochimiques, Universite Paul Sabatier, 31062 Toulouse Cedex 9 (France)

    2009-03-05

    The electrochemical behaviour of AlF{sub 3} was investigated in LiF-CaF{sub 2} medium first with inert tungsten and then with reactive nickel electrodes. Cyclic voltammetry, square-wave voltammetry and chronopotentiometry indicated that the reduction of Al(III) in Al(0) is a single-step process exchanging three electrons: Al(III) + 3e{sup -} = Al The electrochemical reduction is controlled by the diffusion of AlF{sub 3} in the solution. On a nickel electrode, a depolarisation effect for Al(III) reduction was observed in cyclic voltammetry due to the formation of Al-Ni alloys when aluminium ions react with the nickel substrate. Galvanostatic and potentiostatic electrolyses on a nickel electrode led to the formation of four nickel aluminides characterised by SEM: AlNi{sub 3}, AlNi, Al{sub 3}Ni{sub 2} and Al{sub 3}Ni. Layers with a uniform composition of AlNi{sub 3}, AlNi and Al{sub 3}Ni{sub 2} were prepared by varying the electrolysis potential, the current density and duration of intermetallic diffusion.

  15. Modeling of self-controlling hyperthermia based on nickel alloy ferrofluids: Proposition of new nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Delavari, H. Hamid, E-mail: Hamid.delavari@gmail.com [Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Azadi Avenue, 145888-9694 Tehran (Iran, Islamic Republic of); Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120 Uppsala (Sweden); Madaah Hosseini, Hamid R. [Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Azadi Avenue, 145888-9694 Tehran (Iran, Islamic Republic of); Department of Materials Science and Engineering, Sharif University of Technology, Azadi Avenue, 145888-9694 Tehran (Iran, Islamic Republic of); Wolff, Max, E-mail: Max.wolff@physics.uu.se [Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120 Uppsala (Sweden)

    2013-06-15

    In order to provide sufficient heat without overheating healthy tissue in magnetic fluid hyperthermia (MFH), a careful design of the magnetic properties of nanoparticles is essential. We perform a systematic calculation of magnetic properties of Ni-alloy nanoparticles. Stoner–Wohlfarth model based theories (SWMBTs) are considered and the linear response theory (LRT) is used to extract the hysteresis loop of nickel alloy nanoparticles in alternating magnetic fields. It is demonstrated that in the safe range of magnetic field intensity and frequency the LRT cannot be used for the calculation of the area in the hysteresis for magnetic fields relevant for hyperthermia. The best composition and particle size for self-controlling hyperthermia with nickel alloys is determined based on SWMBTs. It is concluded that Ni–V and Ni–Zn are good candidates for self-controlling hyperthermia. - Highlights: ► Systematic calculation of magnetic properties of Ni-alloy NPs with composition has been performed. ► Optimum composition and particle size for self-controlling hyperthermia (SCH) have been determined. ► Ni–V and Ni–Zn nanoparticles are more appropriate candidates for SCH.

  16. Optical modeling of nickel-base alloys oxidized in pressurized water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Clair, A. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS, Universite de Bourgogne, 9 avenue Alain Savary, BP 47870, 21078 Dijon cedex (France); Foucault, M.; Calonne, O. [Areva ANP, Centre Technique Departement Corrosion-Chimie, 30 Bd de l' industrie, BP 181, 71205 Le Creusot (France); Finot, E., E-mail: Eric.Finot@u-bourgogne.fr [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS, Universite de Bourgogne, 9 avenue Alain Savary, BP 47870, 21078 Dijon cedex (France)

    2012-10-01

    The knowledge of the aging process involved in the primary water of pressurized water reactor entails investigating a mixed growth mechanism in the corrosion of nickel-base alloys. A mixed growth induces an anionic inner oxide and a cationic diffusion parallel to a dissolution-precipitation process forms the outer zone. The in situ monitoring of the oxidation kinetics requires the modeling of the oxide layer stratification with the full knowledge of the optical constants related to each component. Here, we report the dielectric constants of the alloys 600 and 690 measured by spectroscopic ellipsometry and fitted to a Drude-Lorentz model. A robust optical stratification model was determined using focused ion beam cross-section of thin foils examined by transmission electron microscopy. Dielectric constants of the inner oxide layer depleted in chromium were assimilated to those of the nickel thin film. The optical constants of both the spinels and extern layer were determined. - Highlights: Black-Right-Pointing-Pointer Spectroscopic ellipsometry of Ni-base alloy oxidation in pressurized water reactor Black-Right-Pointing-Pointer Measurements of the dielectric constants of the alloys Black-Right-Pointing-Pointer Optical simulation of the mixed oxidation process using a three stack model Black-Right-Pointing-Pointer Scattered crystallites cationic outer layer; linear Ni-gradient bottom layer Black-Right-Pointing-Pointer Determination of the refractive index of the spinel and the Cr{sub 2}O{sub 3} layers.

  17. Statistical analysis and optimization of direct metal laser deposition of 227-F Colmonoy nickel alloy

    Science.gov (United States)

    Angelastro, A.; Campanelli, S. L.; Casalino, G.

    2017-09-01

    This paper presents a study on process parameters and building strategy for the deposition of Colmonoy 227-F powder by CO2 laser with a focal spot diameter of 0.3 mm. Colmonoy 227-F is a nickel alloy especially designed for mold manufacturing. The substrate material is a 10 mm thick plate of AISI 304 steel. A commercial CO2 laser welding machine was equipped with a low-cost powder feeding system. In this work, following another one in which laser power, scanning speed and powder flow rate had been studied, the effects of two important process parameters, i.e. hatch spacing and step height, on the properties of the built parts were analysed. The explored ranges of hatch spacing and step height were respectively 150-300 μm and 100-200 μm, whose dimensions were comparable with that of the laser spot. The roughness, adhesion, microstructure, microhardness and density of the manufactured specimens were studied for multi-layer samples, which were made of 30 layers. The statistical significance of the studied process parameters was assessed by the analysis of the variance. The process parameters used allowed to obtain both first layer-to-substrate and layer-to-layer good adhesions. The microstructure was fine and almost defect-free. The microhardness of the deposited material was about 100 HV higher than that of the starting powder. The density as high as 98% of that of the same bulk alloy was more than satisfactory. Finally, simultaneous optimization of density and roughness was performed using the contour plots.

  18. Tensile properties of a nickel-base alloy subjected to surface severe plastic deformation

    Energy Technology Data Exchange (ETDEWEB)

    Tian, J.W. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN (United States); Dai, K. [Quality Engineering and Software Technology, East Hartford, CT 06108 (United States); Villegas, J.C. [Intel Corporation, Chandler, AZ (United States); Shaw, L. [Department of Chemical, Materials and Biomolecular Engineering, University of Connecticut, Storrs, CT (United States)], E-mail: leon.shaw@uconn.edu; Liaw, P.K. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN (United States); Klarstrom, D.L. [Haynes International, Inc., Kokomo, IN (United States); Ortiz, A.L. [Departamento de Ingenieria Mecanica, Energetica y de los Materiales, Universidad de Extremadura, 06071 Badajoz (Spain)

    2008-10-15

    A surface severe plastic deformation (S{sup 2}PD) method has been applied to bulk specimens of HASTELLOY C-2000 alloy, a nickel-base alloy. The mechanical properties of the processed C-2000 alloy were determined via tensile tests and Vickers hardness measurements, whereas the microstructure was characterized using scanning electron microscopy, transmission electron microscopy, and X-ray diffractometry. The improved tensile strength was related to the nanostructure at the surface region, the residual compressive stresses, and the work-hardened surface layer, all of which resulted from the S{sup 2}PD process. To understand the contributions of these three factors, finite element modeling was performed. It was found that the improved tensile strength could be interpreted based on the contributions of nano-grains, residual stresses, and work hardening.

  19. Quantitative in vivo biocompatibility of new ultralow-nickel cobalt-chromium-molybdenum alloys.

    Science.gov (United States)

    Sonofuchi, Kazuaki; Hagiwara, Yoshihiro; Koizumi, Yuichiro; Chiba, Akihiko; Kawano, Mitsuko; Nakayama, Masafumi; Ogasawara, Kouetsu; Yabe, Yutaka; Itoi, Eiji

    2016-09-01

    Nickel (Ni) eluted from metallic biomaterials is widely accepted as a major cause of allergies and inflammation. To improve the safety of cobalt-chromium-molybdenum (Co-Cr-Mo) alloy implants, new ultralow-Ni Co-Cr-Mo alloys with and without zirconium (Zr) have been developed, with Ni contents of less than 0.01%. In the present study, we investigated the biocompatibility of these new alloys in vivo by subcutaneously implanting pure Ni, conventional Co-Cr-Mo, ultralow-Ni Co-Cr-Mo, and ultralow-Ni Co-Cr-Mo with Zr wires into the dorsal sides of mice. After 3 and 7 days, tissues around the wire were excised, and inflammation; the expression of IL-1β, IL-6, and TNF-α; and Ni, Co, Cr, and Mo ion release were analyzed using histological analyses, qRT-PCR, and inductively coupled plasma mass spectrometry (ICP-MS), respectively. Significantly larger amounts of Ni eluted from pure Ni wires than from the other wires, and the degree of inflammation depended on the amount of eluted Ni. Although no significant differences in inflammatory reactions were identified among new alloys and conventional Co-Cr-Mo alloys in histological and qRT-PCR analyses, ICP-MS analysis revealed that Ni ion elution from ultralow-Ni Co-Cr-Mo alloys with and without Zr was significantly lower than from conventional Co-Cr-Mo alloys. Our study, suggests that the present ultralow-Ni Co-Cr-Mo alloys with and without Zr have greater safety and utility than conventional Co-Cr-Mo alloys. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1505-1513, 2016. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  20. [The effect of epigallocatechin gallate (EGCG) on the surface properties of nickel-chromium dental casting alloys after electrochemical corrosion].

    Science.gov (United States)

    Qiao, Guang-yan; Zhang, Li-xia; Wang, Jue; Shen, Qing-ping; Su, Jian-sheng

    2014-08-01

    To investigate the effect of epigallocatechin gallate (EGCG) on the surface properties of nickel-chromium dental alloys after electrochemical corrosion. The surface morphology and surface structure of nickel-chromium dental alloys were examined by stereomicroscope and scanning electron microscopy before and after electrochemical tests in 0 g/L and 1.0 g/L EGCG artificial saliva. The surface element component and chemical states of nickel-chromium dental alloys were analyzed by X-ray photoelectron spectrograph after electrochemical tests in 0 g/L and 1.0 g/L EGCG artificial saliva. More serious corrosion happened on the surface of nickel-chromium alloy in 1.0 g/L EGCG artificial saliva than in 0 g/L EGCG. The diameters of corrosion pits were smaller, and the dendrite structure of the alloy surface was not affected in 0 g/L EGCG. While the diameters of corrosion pits were larger, the dendritic interval of the alloy surface began to merge, and the dendrite structure was fuzzy in 1.0 g/L EGCG. In addition, the O, Ni, Cr, Be, C and Mo elements were detected on the surface of nickel-chromium alloys after sputtered for 120 s in 0 g/L EGCG and 1.0 g/L EGCG artificial saliva after electrochemical corrosion, and the surface oxides were mainly NiO and Cr(2)O(3). Compared with 0 g/L EGCG artificial saliva, the content of O, NiO and Cr(2)O(3) were lower in 1.0 g/L EGCG. The results of surface morphology and the corrosion products both show that the corrosion resistance of nickel-chromium alloys become worse and the oxide content of corrosion products on the surface reduce in 1.0 g/L EGCG artificial saliva.

  1. Hall-Petch relationship in a nanotwinned nickel alloy

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, Leon L. [Department of Chemical, Materials and Biomolecular Engineering, University of Connecticut, Storrs, CT 06269 (United States)], E-mail: leon.shaw@uconn.edu; Ortiz, Angel L. [Departamento de Ingenieria Mecanica, Energetica y de los Materiales Universidad de Extremadura, 06071 Badajoz (Spain); Villegas, Juan C. [Intel Corporation, Chandler, AZ 85226 (United States)

    2008-06-15

    The Hall-Petch relationship in a nanotwinned alloy with absence of dislocation pile-ups is investigated for the first time. It is shown that, when the twin spacing is large (d > 150 nm), the hardness exhibits a d{sup -1/2} dependence. However, when the twin spacing is small (d < 100 nm), a d{sup -1} dependence results. These phenomena are interpreted based on dislocation-mediated mechanisms corroborated by the analysis of electron microscopy and X-ray diffractometry.

  2. Materials corrosion of high temperature alloys immersed in 600C binary nitrate salt.

    Energy Technology Data Exchange (ETDEWEB)

    Kruizenga, Alan Michael; Gill, David Dennis; LaFord, Marianne Elizabeth

    2013-03-01

    Thirteen high temperature alloys were immersion tested in a 60/40 binary nitrate salt. Samples were interval tested up to 3000 hours at 600ÀC with air as the ullage gas. Chemical analysis of the molten salt indicated lower nitrite concentrations present in the salt, as predicted by the equilibrium equation. Corrosion rates were generally low for all alloys. Corrosion products were identified using x-ray diffraction and electron microprobe analysis. Fe-Cr based alloys tended to form mixtures of sodium and iron oxides, while Fe-Ni/Cr alloys had similar corrosion products plus oxides of nickel and chromium. Nickel based alloys primarily formed NiO, with chromium oxides near the oxide/base alloy interface. In625 exhibited similar corrosion performance in relation to previous tests, lending confidence in comparisons between past and present experiments. HA230 exhibited internal oxidation that consisted of a nickel/chromium oxide. Alloys with significant aluminum alloying tended to exhibit superior performance, due formation of a thin alumina layer. Soluble corrosion products of chromium, molybdenum, and tungsten were also formed and are thought to be a significant factor in alloy performance.

  3. Hydrogen embrittlement: the game changing factor in the applicability of nickel alloys in oilfield technology

    Science.gov (United States)

    Sarmiento Klapper, Helmuth; Klöwer, Jutta; Gosheva, Olesya

    2017-06-01

    Precipitation hardenable (PH) nickel (Ni) alloys are often the most reliable engineering materials for demanding oilfield upstream and subsea applications especially in deep sour wells. Despite their superior corrosion resistance and mechanical properties over a broad range of temperatures, the applicability of PH Ni alloys has been questioned due to their susceptibility to hydrogen embrittlement (HE), as confirmed in documented failures of components in upstream applications. While extensive work has been done in recent years to develop testing methodologies for benchmarking PH Ni alloys in terms of their HE susceptibility, limited scientific research has been conducted to achieve improved foundational knowledge about the role of microstructural particularities in these alloys on their mechanical behaviour in environments promoting hydrogen uptake. Precipitates such as the γ', γ'' and δ-phase are well known for defining the mechanical and chemical properties of these alloys. To elucidate the effect of precipitates in the microstructure of the oil-patch PH Ni alloy 718 on its HE susceptibility, slow strain rate tests under continuous hydrogen charging were conducted on material after several different age-hardening treatments. By correlating the obtained results with those from the microstructural and fractographic characterization, it was concluded that HE susceptibility of oil-patch alloy 718 is strongly influenced by the amount and size of precipitates such as the γ' and γ'' as well as the δ-phase rather than by the strength level only. In addition, several HE mechanisms including hydrogen-enhanced decohesion and hydrogen-enhanced local plasticity were observed taking place on oil-patch alloy 718, depending upon the characteristics of these phases when present in the microstructure. This article is part of the themed issue 'The challenges of hydrogen and metals'.

  4. Radiation damage buildup by athermal defect reactions in nickel and concentrated nickel alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, S. [School of Nuclear Science and Technology, Lanzhou University, Lanzhou, People' s Republic of China; Department of Physics and Helsinki Institute of Physics, University of Helsinki, Helsinki, Finland; Nordlund, K. [Department of Physics and Helsinki Institute of Physics, University of Helsinki, Helsinki, Finland; National Research Nuclear University MEPhI, Moscow, Russia; Djurabekova, F. [Department of Physics and Helsinki Institute of Physics, University of Helsinki, Helsinki, Finland; National Research Nuclear University MEPhI, Moscow, Russia; Granberg, F. [Department of Physics and Helsinki Institute of Physics, University of Helsinki, Helsinki, Finland; Zhang, Y. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA; Wang, T. S. [School of Nuclear Science and Technology, Lanzhou University, Lanzhou, People' s Republic of China

    2017-03-09

    We develop a new method using binary collision approximation simulating the Rutherford backscattering spectrometry in channeling conditions (RBS/C) from molecular dynamics atom coordinates of irradiated cells. The approach allows comparing experimental and simulated RBS/C signals as a function of depth without fitting parameters. The simulated RBS/C spectra of irradiated Ni and concentrated solid solution alloys (CSAs, NiFe and NiCoCr) show a good agreement with the experimental results. The good agreement indicates the damage evolution under damage overlap conditions in Ni and CSAs at room temperature is dominated by defect recombination and migration induced by irradiation rather than activated thermally.

  5. Refining a complex ZhS32-VI nickel alloy from silicon and phosphorus by unidirectional solidification of the melt at low solidification front velocities

    Science.gov (United States)

    Sidorov, V. V.; Kablov, D. E.; Min, P. G.; Vadeev, V. E.

    2016-12-01

    The possibility of decreasing the silicon and phosphorus contents in a high-temperature ZhS32-VI nickel alloy by directional movement of solidification front at a velocity V = 6 mm/h has been studied. As a result, the contents of the impurities have decreased as compared to those in the starting alloy; the decrease in the silicon and phosphorus contents is from 2 to 4 and from 14 to 20 times, respectively. Thus, nonmetallic inclusions, in particular, those containing silicon and phosphorus, are moved to the top of the ingot.

  6. OPTIMIZATION OF TECHNOLOGY PERTAINING TO PROCESSING OF MECHANICALLY ALLOYED AND DISPERSIVELY HARDENED NICKEL-CHROMIUM COMPOSITIONS IN SEMI-FINISHED PRODUCTS

    Directory of Open Access Journals (Sweden)

    F. G. Lovshenko

    2010-01-01

    Full Text Available The paper investigates an influence of main technological factors pertaining to processing operations (annealing and hot-tempered  compaction of nano-structural mechanically alloyed granulated nickel-chromium compositions on the properties of highly strong compact semi-products with inter-metallide and oxide hardening. Optimization of the process, phase composition and structure of semi-products have been executed and investigated in the paper.

  7. Auricle reconstruction with a nickel-titanium shape memory alloy as the framework.

    Science.gov (United States)

    Chi, Fang-Lu; Wang, Shen-Jun; Liu, Hong-Jian

    2007-02-01

    The objective of this study is to explore the biocompatibility and implantability of a nickel-titanium (NiTi) alloy in auricle reconstruction. Twelve New Zealand rabbits underwent subcutaneous implantation with a NiTi alloy framework shaped like the human auricle under general anesthesia. The implant was inserted after skin expansion. Implant vascularization was evaluated at months 1, 3, 6, 9, and 12 after implantation by histologic analysis. Immunohistochemical methods were used to examine expression of vascular endothelial growth factor in tissue around the implant. The fibrovascular ingrowth rate of implants was determined by bone scanning using (99m)Tc-PYP. The surface of the NiTi alloy implant was examined microscopically with scanning electron microscopy. The implant harvested showed only partial vascularization at 1 month and completely vascularized at 3 months. The amount of vascular endothelial growth factor-positive cells was markedly increased at 6 months and reached the highest number at 3 months. The fibrovascular ingrowth rate of implant was assessed by (99m)Tc-PYP bone scan using ratios of (99m)Tc-PYP activity in placement regions versus the contralateral normal region. One rabbit had exposure of the NiTi alloy framework as a result of overlying skin flap necrosis. It was rescued with animal skin without the complete removal of the framework. All the other rabbits tolerated the implant well, and there were no complications. The NiTi alloy implant represents an alternative implant for auricular reconstruction.

  8. Synthesis of carbon nanofibers by catalytic CVD of chlorobenzene over bulk nickel alloy

    Science.gov (United States)

    Kenzhin, Roman M.; Bauman, Yuri I.; Volodin, Alexander M.; Mishakov, Ilya V.; Vedyagin, Aleksey A.

    2018-01-01

    Catalytic chemical vapor deposition (CCVD) of chlorobenzene over bulk nickel alloy (nichrome) was studied. The bulk Ni-containing samples being exposed to a contact with aggressive reaction medium undergo self-disintegration followed by growth of carbon nanofibers. This process, also known as a metal dusting, requires the simultaneous presence of chlorine and hydrogen sources in the reaction mixture. Molecule of chlorobenzene complies with these requirements. The experiments on CCVD were performed in a flow-through reactor system. The initial stages of nickel disintegration process were investigated in a closed system under Autogenic Pressure at Elevated Temperature (RAPET) conditions. Scanning and transmission electron microscopies and ferromagnetic resonance spectroscopy were applied to examine the samples after their interaction with chlorobenzene. Introduction of additional hydrogen into the flow-through system was shown to affect the morphology of grown carbon nanofibers.

  9. Mechanodynamical analysis of nickel-titanium alloys for orthodontics application; Analise mecanodinamica de ligas de niquel-titanio para aplicacao ortodontica

    Energy Technology Data Exchange (ETDEWEB)

    Arruda, Carlos do Canto

    2002-07-01

    Nickel-titanium alloys may coexist in more than one crystalline structure. There is a high temperature phase, austenite, and a low temperature phase, martensite. The metallurgical basis for the superelasticity and the shape memory effect relies in the ability of these alloys to transform easily from one phase to another. There are three essential factors for the orthodontist to understand nickel-titanium alloys behaviour: stress; deflection; and temperature. These three factors are related to each other by the stress-deflection, stress-temperature and deflection-temperature diagrams. This work was undertaken with the objective to analyse commercial nickel-titanium alloys for orthodontics application, using the dynamical mechanical analyser - DMA. Four NiTi 0,017 X 0,025'' archwires were studied. The archwires were Copper NiTi 35 deg C (Ormco), Neo Sentalloy F200 (GAC), Nitinol Superelastic (Unitek) and NiTi (GAC). The different mechanodynamical properties such as elasticity and damping moduli were evaluated. Each commercial material was evaluated with and without a 1 N static force, aiming to evaluate phase transition temperature variation with stress. The austenitic to martensitic phase ratio, for the experiments without static force, was in the range of 1.59 to 1.85. For the 1 N static force tests the austenitic to martensitic phase ratio, ranged from 1.28 to 1.57 due to the higher martensite elasticity modulus. With elastic modulus variation with temperature behaviour, the orthodontist has the knowledge of the force variation applied in the tooth in relation to the oral cavity temperature change, for nickel-titanium alloys that undergo phase transformation. The damping capacity of the studied alloys depends on the materials state: martensitic phase; austenitic phase or during phase transformation. The martensitic phase shows higher dumping capacity. During phase transformation, an internal friction peak may be observed for the CuNiTi 35 deg C and Neo

  10. Late complications of nickel-titanium alloy stent in tracheal stenosis.

    Science.gov (United States)

    Chen, Wenxian; Ruan, Yanyan

    2012-04-01

    To investigate and treat the late complications of using nickel-titanium alloy stents in laryngotracheal, bronchial, and esophageal stenosis patients who developed severe laryngotracheal stenosis (SLS). Retrospective clinical study. Thirteen patients with SLS or tracheoesophageal fistula secondary to insertion of a nickel-titanium alloy stent for treatment of laryngotracheal, bronchial, or esophageal stenosis treated between May 2004 and March 2010 were retrospectively analyzed. Of the 13 total patients, nine had one stent placed, and four had two stents placed. The late complications observed were glottic and/or subglottic extension of cervical tracheal stenosis (n = 6), new stricture of the thoracic trachea (n = 4), severe left bronchial stricture with massive left pulmonary collapse (n = 1), and cervical tracheoesophageal fistula (n = 2). Six patients with glottic and/or subglottic to cervical tracheal stenosis underwent successful laryngotracheal reconstruction. Two patients with subglottic and upper thoracic tracheal stenosis were successfully treated by staged operation for the stenosis. Two patients with subglottic and distal thoracic tracheal stenosis are still undergoing treatment. One patient with severe left bronchial stricture and massive left pulmonary collapse has been treated but has not achieved full recovery. One patient with cervical tracheoesophageal fistula underwent successful repair but died later from metastatic disease. One patient with tracheoesophageal fistula died from massive hemorrhage and asphyxiation induced by the stent, which had not been removed. The nickel-titanium alloy stents should be used with extreme caution in patients with laryngotracheal, bronchial, or esophageal stenosis treatment that can be corrected by surgical therapy. Copyright © 2012 The American Laryngological, Rhinological, and Otological Society, Inc.

  11. Nanoscale nickel-titanium shape memory alloys thin films fabricated by using biased target ion beam deposition

    Science.gov (United States)

    Hou, Huilong

    Shape memory alloys offer the highest work output per unit volume among smart materials and have both high actuation stress and large recoverable strain. Miniaturization of materials and devices requires shape memory actuation which is uncompromised at a small scale. However, size effects need to be understood in order to scale shape memory actuation with the minimum size critical to device design. Controlling material quality and properties is essential in fabrication of shape memory alloys into nanometer regime. This work demonstrates a novel fabrication technique, biased target ion beam deposition (BTIBD), which uses additional adatom energy in order to fabricate high-quality nickel-titanium (NiTi) alloys thin films with nanometer thickness. These fabricated ultrathin NiTi films provide insight into the size scale dependence of shape memory functionality at nanoscale regime. BTIBD provides additional adatom energy to the growing film in order to fundamentally tailor the film growth mode for quality and properties. An independent ion beam source is customized in BTIBD to provide low-energy ions (tens of eV) during growth of films on substrates. Pure Ti and pure Ni targets are co-sputtering in BTIBD to fabricate NiTi thin films. The prepared NiTi films are continuous, and the thickness ranges from several tens to a few hundreds nanometers. The composition is controllable over the range of Ni-rich (>50.5 at% Ni), near-equiatomic, and Ti-rich (stress measurements. The thermal hysteresis in these films is considerably smaller (up to 50 %) than that in magnetron sputtered films. Free-standing NiTi alloy 1D nanowires are machined from the NiTi alloy thin films by using nanoskiving. Results are also shown for focused ion beam 1D micropillars, 2D thin sheet with nanometer thickness, and 2D micro-double shear specimen as additional objects to investigate geometric/microstructural size effect. Nanoskiving combines deposition of thin films with thin sectioning to generate

  12. Microstructure characterization of alloy 625 deposited on nickel foam using air plasma spraying

    Energy Technology Data Exchange (ETDEWEB)

    Azarmi, F.; Saaedi, J.; Coyle, T.W.; Mostaghimi, J. [Center for Advanced Coating Technologies, University of Toronto (Canada)

    2008-05-15

    Ni-based superalloy 625 has been deposited on nickel foam by air plasma spraying (APS) using an optimized set of spraying parameters under two different substrate conditions. For condition (i) the substrate was not cooled during spraying and for condition (ii) the substrate constantly cooled using air jets during spraying. Microstructural characteristics of the as-sprayed coating microstructure were examined by a combination of optical and scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), image analysis, and X-ray diffraction (XRD) analysis, and compared to those of the alloy 625 powder used for spraying. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  13. Structural evaluation of a nickel base super alloy metal foam via NDE and finite element

    Science.gov (United States)

    Abdul-Aziz, Ali; Abumeri, G.; Garg, Mohit; Young, P. G.

    2008-03-01

    Cellular materials are known to be useful in the application of designing light but stiff structures. This applies to various components used in various industries such as rotorcraft blades, car bodies or portable electronic devices. Structural application of the metal foam is typically confined to light weight sandwich panels, made up of thin solid face sheets and a metallic foam core. The resulting high-stiffness structure is lighter than that constructed only out of the solid metal material. The face sheets carry the applied in-plane and bending loads and the role of the foam core is separate the face sheets to carry some of the shear stresses, while remaining integral with the face sheet. Many challenges relating to the fabrication and testing of these metal foam panels continue to exist due to some mechanical properties falling short of their theoretical potential. Hence in this study, a detailed three dimensional foam structure is generated using series of 2D Computer Tomography (CT) scans, on Haynes 25 metal foam. Series of the 2D images are utilized to construct a high precision solid model including all the fine details within the metal foam as detected by the CT scanning technique. Subsequently, a finite element analysis is then performed on an as fabricated metal foam microstructures to evaluate the foam structural durability and behavior under tensile and compressive loading conditions. The analysis includes a progressive failure analysis (PFA) using GENOA code to further assess the damage initiation, propagation, and failure. The open cell metal foam material is a cobalt-nickel-chromium-tungsten alloy that combines excellent high-temperature strength with good resistance to oxidizing environments up to 1800 °F (980 °C) for prolonged exposures. The foam is formed by a powder metallurgy process with an approximate 100 pores per inch (PPI).

  14. Probability of Occurrence of Life-Limiting Fatigue Mechanism in P/M Nickel-Based Alloys (Postprint)

    Science.gov (United States)

    2016-03-30

    Microstructures 8 and 9 in Figure 3(b) can be considered to correspond to the " Small " and "Large" seeded specimens under no peening with volumetric...AFRL-RX-WP-JA-2017-0146 PROBABILITY OF OCCURRENCE OF LIFE-LIMITING FATIGUE MECHANISM IN P/M NICKEL-BASED ALLOYS (POSTPRINT) M.J...February 2016 4. TITLE AND SUBTITLE PROBABILITY OF OCCURRENCE OF LIFE-LIMITING FATIGUE MECHANISM IN P/M NICKEL-BASED ALLOYS (POSTPRINT) 5a

  15. Internal nitridation of nickel-base alloys; Innere Nitrierung von Nickelbasis-Legierungen

    Energy Technology Data Exchange (ETDEWEB)

    Krupp, U.; Christ, H.J. [Siegen Univ. (Gesamthochschule) (Germany). Inst. fuer Werkstofftechnik

    1998-12-31

    The chromuim concentration is the crucial variable in nitridation processes in nickel-base alloys. Extensive nitridation experiments with various specimen alloys of the system Ni-Cr-Al-Ti have shown that the Cr itself starts to form nitrides as from elevated initial concentrations of about 10 to 20 weight%, (depending on temperature), but that lower concentrations have an earlier effect in that they induce a considerable increase in the N-solubility of the nickel-base alloys. This causes an accelerated nitridation attack on the alloying elements Ti and Al. Apart from experimental detection and analysis, the phenomenon of internal nitridation could be described as well by means of a mathematical model calculating the diffusion with the finite-differences method and determining the precipitation thermodynamics by way of integrated equilibrium calculations. (orig./CB) [Deutsch] Im Verlauf der Hochtemperaturkorrosion von Nickelbasis-Superlegierungen kann durch beanspruchungsbedingte Schaedigungen der Oxiddeckschicht ein Verlust der Schutzwirkung erfolgen und als Konsequenz Stickstoff aus der Atmosphaere in den Werkstoff eindringen. Der eindiffundierende Stickstoff bildet vor allem mit den Legierungselementen Al, Cr und Ti Nitridausscheidungen, die zu einer relativ rasch fortschreitenden Schaedigung fuehren koennen. Eine bedeutende Rolle bei diesen Nitrierungsprozessen in Nickelbasislegierungen spielt die Cr-Konzentration in der Legierung. So ergaben umfangreiche Nitrierungsexperimente an verschiedenen Modellegierungen des Systems Ni-Cr-Al-Ti, dass Cr zwar selbst erst ab Ausgangskonzentrationen von ca. 10-20 Gew.% (abhaengig von der Temperatur) Nitride bildet, allerdings bereits bei geringen Konzentrationen die N-Loeslichkeit von Nickelbasis-Legierungen entscheidend erhoeht. Dies hat zur Folge, dass es zu einem beschleunigten Nitrierungsangriff auf die Legierungselemente Ti und Al kommt. Neben den experimentellen Untersuchungen konnte das Phaenomen der inneren

  16. The use of new PHACOMP in understanding the solidification microstructure of nickel base alloy weld metal

    Science.gov (United States)

    Cieslak, M. J.; Knorovsky, G. A.; Headley, T. J.; Romig, A. D.

    1986-12-01

    The weld metal microstructures of five commercial nickel base alloys (HASTELLOYS* C-4, C-22, and C-276, and INCONELS* 625 and 718) have been examined by electron probe microanalysis and analytical electron microscopy. It has been found that solidification terminates in many of these alloys with the formation of a constituent containing a topologically-close-packed (TCP) intermetallic phase (i.e., σ, P, Laves). Electron microprobe examination of gas-tungsten-arc welds revealed a solidification segregation pattern of Ni depletion and solute enrichment in interdendritic volumes. New PHACOMP calculations performed on these segregation profiles revealed a pattern of increasing M d (metal- d levels) in traversing from a dendrite core to an adjacent interdendritic volume. In alloys forming a terminal solidification TCP constituent, the calculated M d values in interdendritic regions were greater than the critical M d values for formation of σ as stated by Morinaga et al. Implications of the correlation between TCP phase formation and M d in the prediction of weld metal solidification microstructure, prediction of potential hot-cracking behavior, and applications in future alloy design endeavors are discussed.

  17. UNDERSTANDING THE MECHANISMS CONTROLLING ENVIRONMENTALLY-ASSISTED INTERGRANULAR CRACKING OF NICKEL-BASE ALLOYS

    Energy Technology Data Exchange (ETDEWEB)

    Gary S. Was

    2004-02-13

    Creep and IG cracking of nickel-base alloys depend principally on two factors--the deformation behavior and the effect of the environment. We have shown that both contribute to the observed degradation in primary water. The understanding of cracking does not lie wholly within the environmental effects arena, nor can it be explained only by intrinsic mechanical behavior. Rather, both processes contribute to the observed behavior in primary water. In this project, we had three objectives: (1) to verify that grain boundaries control deformation in Ni-16Cr-9Fe at 360 C, (2) to identify the environmental effect on IGSCC, and (3) to combine CSLBs and GBCs to maximize IGSCC resistance in Ni-Cr-Fe in 360 C primary water. Experiments performed in hydrogen gas at 360 C confirm an increase in the primary creep rate in Ni-16Cr-9Fe at 360 C due to hydrogen. The creep strain transients caused by hydrogen are proposed to be due to the collapse of dislocation pile-ups, as confirmed by observations in HVEM. The observations only partially support the hydrogen-enhanced plasticity model, but also suggest a potential role of vacancies in the accelerate creep behavior in primary water. In high temperature oxidation experiments designed to examine the potential for selective internal oxidation in the IGSCC process, cracking is greatest in the more oxidizing environments compared to the low oxygen potential environments where nickel metal is stable. In Ni-Cr-Fe alloys, chromium oxides form preferentially along the grain boundaries, even at low oxygen potential, supporting a potential role in grain boundary embrittlement due to preferential oxidation. Experiments designed to determine the role of grain boundary deformation on intergranular cracking have established, for the first time, a cause-and-effect relationship between grain boundary deformation and IGSCC. That is, grain boundary deformation in Ni-16Cr-9Fe in 360 C primary water leads to IGSCC of the deformed boundaries. As well

  18. High strength forgeable tantalum base alloy

    Science.gov (United States)

    Buckman, R. W., Jr.

    1975-01-01

    Increasing tungsten content of tantalum base alloy to 12-15% level will improve high temperature creep properties of existing tantalum base alloys while retaining their excellent fabrication and welding characteristics.

  19. Effect of recasting on the thickness of metal-ceramic interface of nickel-chromium and cobalt-chromium alloys

    OpenAIRE

    Mirković Nemanja; Draganjac Miroslav; Stamenković Dragoslav; Ristić Ljubiša

    2008-01-01

    Introduction/Aim. This research was done to establish recasting effects of nickel-chromium and cobalt-chromium alloys on the thickness of their metal-ceramic interface in making fixed partial dentures. Metal-ceramic interface determines their functional integrity and prevents damages on ceramics during mastication. Investigation of metal-ceramic samples is supposed to show if base metal alloys for metalceramics are successfully recycled without any risk of reduction of metal-ceramic interface...

  20. Effect of recasting on the thickness of metal-ceramic interface of nickel-chromium and cobalt-chromium alloys

    Directory of Open Access Journals (Sweden)

    Mirković Nemanja

    2008-01-01

    Full Text Available Introduction/Aim. This research was done to establish recasting effects of nickel-chromium and cobalt-chromium alloys on the thickness of their metal-ceramic interface in making fixed partial dentures. Metal-ceramic interface determines their functional integrity and prevents damages on ceramics during mastication. Investigation of metal-ceramic samples is supposed to show if base metal alloys for metalceramics are successfully recycled without any risk of reduction of metal-ceramic interface thickness. Methods. The research was performed as an experimental study. Per six metal-ceramic samples of nickel-chromium alloy (Wiron99 and cobalt-chromium alloy (Wirobond C were made each. Alloy residues were recycled through twelve casting generations with the addition of 50% of new alloy on the occasion of every recasting. Analysis Energy Dispersive X-ray (EDX (Oxford Instruments and Scanning Electon Microscop (SEM analysis (JEOL were used to determine thickness of metal-ceramic interface together with PC Software for quantification of visual information's (KVI POPOVAC. Results. Results of this research introduced significant differences between thickness of metal-ceramic interface in every examined recycle generation. Recasting had negative effect on thickness of metal-ceramic interface of the examined alloys. This research showed almost linear reduction of elastic modulus up to the 12th generation of recycling. Conclusion. Recasting of nickel-chromium and cobaltchromium alloys is not recommended because of reduced thickness of metal-ceramic interface of these alloys. Instead of recycling, the alloy residues should be returned to the manufacturers.

  1. Interactions at the mould – modifying coating – molten nickel alloy interface

    Directory of Open Access Journals (Sweden)

    J. Michalska

    2011-07-01

    Full Text Available The study describes thermal-chemical interactions that take place in the molten nickel alloy-ceramic mould system, where the mould is either coated with a modifying coating („blue” mould or is not („white” mould. The ceramic mould based on zirconium silicate was made by investment process at the WSK Rzeszów Foundry. The main component of the modifying coating was cobalt aluminate CoAl2O4 added in an amount of 10%. Thermodynamic calculations indicated the possibility of chemical reactions taking place between the chemically active nickel alloy constituents (Al, Ti, Hf, Ta and Nb and the components of a ceramic mould and modifying coating. The result of such interactions is the risk of the formation of cracks on the surface of mould and molten metal penetration into these cracks, combined with the formation of casting defects, like burns-on, pitting, etc., as proved by extensive X-ray microanalysis. Changes of chemical composition in the surface layer of castings were also reported.

  2. Effect of Water Nutrient Pollution on Long-Term Corrosion of 90:10 Copper Nickel Alloy

    Directory of Open Access Journals (Sweden)

    Robert E. Melchers

    2015-11-01

    Full Text Available Due to their good corrosion resistance, copper and copper alloys such as 90:10 Cu-Ni are used extensively in high-quality marine and industrial piping systems and also in marine, urban, and industrial environments. Their corrosion loss and pitting behaviour tends to follow a bi-modal trend rather than the classic power law. Field data for 90:10 copper nickel immersed in natural seawater are used to explore the effect of water pollution and in particular the availability of critical nutrients for microbiologically induced corrosion. It is shown, qualitatively, that increased dissolved inorganic nitrogen increases corrosion predominantly in the second, long-term, mode of the model. Other, less pronounced, influences are salinity and dissolved oxygen concentration.

  3. Thermodynamics of copper-nickel alloys containing aluminum, silicon, titanium, and chromium relative to their use in ceramic brazing

    Energy Technology Data Exchange (ETDEWEB)

    Williams, R.O.

    1984-11-01

    By varying the copper-to-nickel ratio the activity coefficients of Al, Si, Ti, and Cr can be varied over a wide range. Thus to a degree one can tailor the behavior of such alloys for usefulness in brazing ceramics. Further, considerable amounts of these active elements can be present while the ability of carbon to reduce the surface oxide film in a high-vacuum system is retained. The critical aluminum concentrations required to prevent the formation of SiO/sub 2/, TiO, or Cr/sub 2/O/sub 3/ by reaction with Al/sub 2/O/sub 3/ are calculated. The simultaneous presence of the four active additions will presumably promote wetting without making the surface deoxidation more difficult.

  4. Effect of Water Nutrient Pollution on Long-Term Corrosion of 90:10 Copper Nickel Alloy.

    Science.gov (United States)

    Melchers, Robert E

    2015-11-27

    Due to their good corrosion resistance, copper and copper alloys such as 90:10 Cu-Ni are used extensively in high-quality marine and industrial piping systems and also in marine, urban, and industrial environments. Their corrosion loss and pitting behaviour tends to follow a bi-modal trend rather than the classic power law. Field data for 90:10 copper nickel immersed in natural seawater are used to explore the effect of water pollution and in particular the availability of critical nutrients for microbiologically induced corrosion. It is shown, qualitatively, that increased dissolved inorganic nitrogen increases corrosion predominantly in the second, long-term, mode of the model. Other, less pronounced, influences are salinity and dissolved oxygen concentration.

  5. High Temperature Deformation Mechanisms in a DLD Nickel Superalloy

    Directory of Open Access Journals (Sweden)

    Sean Davies

    2017-04-01

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

  6. High Temperature Deformation Mechanisms in a DLD Nickel Superalloy.

    Science.gov (United States)

    Davies, Sean; Jeffs, Spencer; Lancaster, Robert; Baxter, Gavin

    2017-04-26

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

  7. High specific energy, high capacity nickel-hydrogen cell design

    Science.gov (United States)

    Wheeler, James R.

    1993-01-01

    A 3.5 inch rabbit-ear-terminal nickel-hydrogen cell was designed and tested to deliver high capacity at steady discharge rates up to and including a C rate. Its specific energy yield of 60.6 wh/kg is believed to be the highest yet achieved in a slurry-process nickel-hydrogen cell, and its 10 C capacity of 113.9 AH the highest capacity yet of any type in a 3.5 inch diameter size. The cell also demonstrated a pulse capability of 180 amps for 20 seconds. Specific cell parameters and performance are described. Also covered is an episode of capacity fading due to electrode swelling and its successful recovery by means of additional activation procedures.

  8. Synthesis, structure and properties of nickel-iron-tungsten alloy electrodeposits - Part II: Effect of microstructure on hardness, electrical and magnetic properties

    Directory of Open Access Journals (Sweden)

    Ćirović Nataša

    2016-01-01

    Full Text Available Nanostructured nickel-iron-tungsten alloys were produced by electrodeposition from an ammoniacal citrate bath. The tungsten content of the alloy ranged from 0.8 wt.% to 11 wt.%, and the crystal grain size of the FCC phase of the solid solution of iron and tungsten in nickel was between 14 nm and 3.3 nm. The amorphous phase content of the alloy increases with decreasing crystal grain size. As the amorphous phase content increases, the magnetization, electrical conductivity and hardness of the alloy decrease. Annealing the alloy to crystallization temperature results in structural relaxation during which the alloy undergoes short-range ordering in conjunction with decreases in the density of chaotically distributed dislocations and internal microstrain level, which increases the exchange integral value, the electronic density of states at the Fermi level, the mean free path of electrons, the ordering and the mean size of cluster in the sliding plane and results in more uniform orientation of dipole moments of certain nanoparticles. These changes: a increase the mobility of magnetic domain walls, facilitate the orientation of domains in the external magnetic field and cause an increase in magnetization; b cause a decrease in electrical resistance, and c impede the sliding of grain boundaries and increase the hardness of the alloy. Annealing the alloys at temperatures above 400ºC results in amorphous phase crystallization and larger crystal grains of the FCC phase, along with a decrease in the density of chaotically distributed dislocations and a decrease in internal microstrain level. The formation of larger crystal grains reduces the hardness of the alloy, decreases its specific electrical resistance and impedes both the orientation of certain magnetic domains and the shift of walls of already oriented domains, thus inducing a decrease in magnetization. The heat released during the milling of Ni87.3Fe11.3W1.4 alloy with FCC-phase crystal grains 8

  9. High temperature alloy chloridation at 850 C

    Energy Technology Data Exchange (ETDEWEB)

    Chevalier, S.; Bekaddour, A. [Laboratoire de Recherches sur la Reactivite des Solides, UMR 5613 CNRS, Universite de Bourgogne, 9 avenue Alain Savary, 21078 Dijon (France); Ched' Homme, S. [DTM/SRPU/LPPU, CEA Valduc, 21120 Is-sur-Tille (France); Amilain-Basset, K.; Buisson, L. [Interface Caracterisation des Materiaux, Universite de Bourgogne, 21078 Dijon (France)

    2007-05-15

    The resistance of eight alloys against chloridation was tested at 850 C in Ar/Cl{sub 2} (2.5% Cl{sub 2}) for 15 min. Pre-oxidation treatments were performed for 1 h and 8 h at 850 C in order to produce a thin, adherent and protective oxide scale able to improve the chloridation behaviour of the tested materials. The chloridised sample morphologies were compared to the morphologies observed on the non pre-oxidised samples. The alloys containing a large amount of iron did not exhibit any chloridation resistance, even after pre-oxidation, and were severely damaged. The nickel based alloys gave interesting results but were also attacked by chloride, probably by the ''active oxidation'' mechanism. The duration of the pre-oxidation treatment plays an important role, since the 8 h pre-oxidation appears more beneficial than the 1 h pre-oxidation, to delay the chloridation, probably because of the best quality of the oxide layer grown during 8 h. For the nickel based materials, the effects of chloride appear less severe than for the iron-based alloys, but are not stopped. The ''active oxidation'' mechanism is proposed to be responsible for the degradation of the tested materials. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  10. Two-phase chromium-niobium alloys exhibiting improved mechanical properties at high temperatures

    Science.gov (United States)

    Liu, Chain T.; Takeyama, Masao

    1994-01-01

    The specification discloses chromium-niobium alloys which exhibit improved mechanical properties at high temperatures in the range of 1250.degree. C. and improved room temperature ductility. The alloys contain a Cr.sub.2 Nb-rich intermetallic phase and a Cr-rich phase with an overall niobium concentration in the range of from about 5 to about 18 at. %. The high temperature strength is substantially greater than that of state of the art nickel-based superalloys for enhanced high temperature service. Further improvements in the properties of the compositions are obtained by alloying with rhenium and aluminum; and additional rare-earth and other elements.

  11. Evaluation of effect of recasting of nickel-chromium alloy on its castability using different investment materials: An in vitro study

    Directory of Open Access Journals (Sweden)

    Abhinav Sharma

    2016-01-01

    Conclusions: Within the limitations of the study, it was concluded that there was no significant difference found in castability of different percentage combinations of new and once casted alloy using two investment materials. The addition of new alloy during recasting to maintain the castability of nickel-chromium alloy may therefore not be required.

  12. Studying the effect of Ruthenium on High Temperature Mechanical Properties of Nickel Based Superalloys and Determining the Universal Behavior of Ruthenium at Atomic Scale with respect to alloying elements, Stress and Temperature

    Directory of Open Access Journals (Sweden)

    Sriswaroop Dasari

    2016-10-01

    Full Text Available Any property of a material is a function of its microstructure and microstructure is a function of material composition. So, to maximize the desired properties of a material, one has to understand the evolution of microstructure which in turn is nothing but the reflection of the role of alloying elements. Research has not been done to understand the universal behavior of a certain base/alloying element. Let’s take the example of Cl- ion in HCl, we all know that in general, chloride ion can only be replaced by Fluoride or oxygen ion and that no other ion can replace it. But when you consider a metal like Ni, Co, Cr, Fe etc. there is no establishment that it behaves only in a certain way. Though I concord to the fact that discovery of universal behavior of Ni is lot complex than chloride ion, I think that future research should be focused in this direction also. Superalloys are the candidate materials required to improve thermal efficiency of a gas turbine by allowing higher turbine inlet gas temperatures. Gas turbines are the heart of local power systems, next generation jet engines and high performance space rockets. Recent research in superalloys showed that addition of some alloying elements in minor quantities can result in drastic change in properties. Such an alloying element is Ruthenium (Ru. Addition of Ruthenium to superalloys has shown improvement in mechanical properties by an order of magnitude. However reasons for such improvement are not known yet. Hence, there is a need to identify its role and discover the universal behavior of ruthenium to utilize it efficiently. In this proposal, we study materials with different compositions that are derived based on one ruthenium containing superalloy, and different thermomechanical history. Based on the evolution of microstructures and results of mechanical testing, we plan to determine the exact role of Ruthenium and prediction of its behavior with respect to other elements in the material

  13. Characterization and assessment of dermal and inhalable nickel exposures in nickel production and primary user industries.

    Science.gov (United States)

    Hughson, G W; Galea, K S; Heim, K E

    2010-01-01

    electrolytic processes for nickel recovery (GM = 0.04 mg m(-3) total nickel, containing 82% soluble nickel) and those jobs involving contact with soluble nickel compounds (GM = 0.02 mg m(-3) total nickel content, containing 76% soluble nickel). The stainless steel workers were exposed to low concentrations of relatively insoluble airborne nickel species (GM = 0.03 mg m(-3) total nickel, containing 1% soluble nickel). A statistically significant correlation was observed between dermal exposures for all anatomical areas across all tasks. In addition, the dermal and inhalable (total) nickel exposures were similarly associated. Overall, dermal exposures to nickel, nickel compounds, and nickel alloys were relatively low. However, exposures were highly variable, which can be explained by the inconsistent use of personal protective equipment, varying working practices, and different standards of automation and engineering controls within each exposure category.

  14. Titanium-nickel shape memory alloy foams for bone tissue engineering.

    Science.gov (United States)

    Xiong, J Y; Li, Y C; Wang, X J; Hodgson, P D; Wen, C E

    2008-07-01

    Titanium-nickel (TiNi) shape memory alloy (SMA) foams with an open-cell porous structure were fabricated by space-holder sintering process and characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. The mechanical properties and shape memory properties of the TiNi foam samples were investigated using compressive test. Results indicate that the plateau stresses and elastic moduli of the foams under compression decrease with the increase of their porosities. The plateau stresses and elastic moduli are measured to be from 1.9 to 38.3 MPa and from 30 to 860 MPa for the TiNi foam samples with porosities ranged from 71% to 87%, respectively. The mechanical properties of the TiNi alloy foams can be tailored to match those of bone. The TiNi alloy foams exhibit shape memory effect (SME), and it is found that the recoverable strain due to SME decreases with the increase of foam porosity.

  15. Evaluation of Metallurgical Quality of Master Heat IN-713C Nickel Alloy Ingots

    Directory of Open Access Journals (Sweden)

    F. Binczyk

    2012-12-01

    Full Text Available The paper presents the results of evaluation of the metallurgical quality of master heat ingots and of the identification of non-metallic inclusions (oxides of Al., Zr, Hf, Cr, etc., which have been found in the shrinkage cavities formed in these ingots. The inclusions penetrate into the liquid alloy, and on pouring of mould are transferred to the casting, especially when the filtering system is not sufficiently effective. The specific nature of the melting process of nickel and cobalt alloys, carried out in vacuum induction furnaces,excludes the possibility of alloy refining and slag removal from the melt surface. Therefore, to improve the quality of castings (parts of aircraft engines, it is so important to evaluate the quality of ingots before charging them into the crucible of an induction furnace. It has been proved that one of the methods for rapid quality evaluation is an ATD analysis of the sample solidification process, where samples are taken from different areas of the master heat ingot. The evaluation is based on a set of parameters plotted on the graph of the dT/dt derivative curve during the last stage of the solidification process in a range from TEut to Tsol.

  16. Microstructure, nickel suppression and mechanical characteristics of electropolished and photoelectrocatalytically oxidized biomedical nickel titanium shape memory alloy.

    Science.gov (United States)

    Chu, C L; Guo, C; Sheng, X B; Dong, Y S; Lin, P H; Yeung, K W K; Chu, Paul K

    2009-07-01

    A new surface modification protocol encompassing an electropolishing pretreatment (EP) and subsequent photoelectrocatalytic oxidation (PEO) has been developed to improve the surface properties of biomedical nickel titanium (NiTi) shape memory alloy (SMA). Electropolishing is a good way to improve the resistance to localized breakdown of NiTi SMA whereas PEO offers the synergistic effects of advanced oxidation and electrochemical oxidation. Our results indicate that PEO leads to the formation of a sturdy titania film on the EP NiTi substrate. There is an Ni-free zone near the top surface and a graded interface between the titania layer and NiTi substrate, which bodes well for both biocompatibility and mechanical stability. In addition, Ni ion release from the NiTi substrate is suppressed, as confirmed by the 10-week immersion test. The modulus and hardness of the modified NiTi surface increase with larger indentation depths, finally reaching plateau values of about 69 and 3.1GPa, respectively, which are slightly higher than those of the NiTi substrate but much lower than those of a dense amorphous titania film. In comparison, after undergoing only EP, the mechanical properties of NiTi exhibit an inverse change with depth. The deformation mechanism is proposed and discussed. Our results indicate that surface modification by dual EP and PEO can notably suppress Ni ion release and improve the biocompatibility of NiTi SMA while the surface mechanical properties are not compromised, making the treated materials suitable for hard tissue replacements.

  17. Influence of Nickel Addition on Properties of Secondary AlSi7Mg0.3 Alloy

    Directory of Open Access Journals (Sweden)

    Richtárech L.

    2015-06-01

    Full Text Available This paper deals with influence on segregation of iron based phases on the secondary alloy AlSi7Mg0.3 microstructure by nickel. Iron is the most common and harmful impurity in aluminum casting alloys and has long been associated with an increase of casting defects. In generally, iron is associated with the formation of Fe-rich intermetallic phases. It is impossible to remove iron from melt by standard operations. Some elements eliminates iron by changing iron intermetallic phase morphology, decreasing its extent and by improving alloy properties. Realization of experiments and results of analysis show new view on solubility of iron based phases during melt preparation with higher iron content and influence of nickel as iron corrector of iron based phases.

  18. Analytical and electrochemical evaluation of the in vitro corrosion behavior of nickel-chrome and cobalt-chrome casting alloys for metal-ceramic restorations.

    Science.gov (United States)

    Yfantis, Constaninos; Yfantis, Dimitrios; Anastassopoulou, Jane; Theophanides, Theophilos

    2007-03-01

    In this study we examined the hypothesis based on relevant literature survey that the in vitro corrosion behavior of a Cobalt-chrome dental casting alloy for metal-ceramic restorations is better than that of a Nickel-chrome dental casting alloy. The corrosion released metal ions were analysed by Inductively Coupled Plasma-Atomic Emission Spectroscopy. Moreover, the specimens were electrochemically tested by linear polarization. The statistical analysis of the results showed statistically significant differences in corrosion rates of Nickel-chrome alloy and Cobalt-chrome alloy calculated by analytical and electrochemical measurements. The hypothesis was confirmed and the results showed that the corrosion rates of the Cobalt-chrome alloy were lower than that of the Nickel-chrome alloy.

  19. Oxidation-induced phase transformations and lifetime limits of chromia-forming nickel-base alloy 625

    Energy Technology Data Exchange (ETDEWEB)

    Chyrkin, Anton

    2011-12-05

    For its high creep resistance the commercial nickel-base alloy 625 relies on solid solution strengthening in combination with precipitation hardening by formation of δ-Ni{sub 3}Nb and (Ni,Mo,Si){sub 6}C precipitates during high-temperature service. In oxidizing environments the alloy forms a slow growing, continuous chromia layer on the material surface which protects the alloy against rapid oxidation attack. The growth of the chromia base oxide scale results during exposure at 900-1000 C in oxidation-induced chromium depletion in the subsurface zone of the alloy. Microstructural analyses of the cross-sectioned specimens revealed that this process results in formation of a wide subsurface zone in which the mentioned strengthening phases are dissolved, in spite of the fact that both phases do not contain substantial amounts of the scale-forming element chromium. The cross-sectional analyses revealed that, in parallel to the formation of a precipitate depleted zone, a thin, continuous layer of niobium-rich intermetallic precipitates formed in the immediate vicinity of the scale/alloy interface. The Subsurface Phase Enrichment (abbreviated as SPE) was shown to be the result of an uphill-diffusion of niobium, i.e. the element stabilizing the strengthening precipitates δ-Ni{sub 3}Nb, in the chromium activity gradient and is thus a natural consequence of the oxidation-induced chromium depletion beneath the chromia scale. The thermodynamic calculations carried out using the Thermo-Calc/DICTRA software packages revealed that in alloy 625 the chemical activity of niobium decreases with decreasing chromium content. As chromium is being continuously removed from the alloy as the result of the chromia scale growth, the zone of lowest Nb-activity is formed in the location with the lowest chromium concentration, i.e. the scale/alloy interface. This creates a driving force for Nb to diffuse towards the scale/alloy interface against its own concentration gradient, which is known

  20. The properties and transport phenomena in oxide films on iron, nickel, chromium and their alloys in aqueous environments

    Energy Technology Data Exchange (ETDEWEB)

    Laitinen, T.; Bojinov, M.; Betova, I.; Maekelae, K.; Saario, T. [VTT Manufacturing Technology, Espoo (Finland)

    1999-01-01

    The construction materials used in coolant systems in nuclear power plants become covered with oxide films as a result of exposure to the aqueous environment. The susceptibility of the materials to different forms of corrosion, as well as the extent of the incorporation of radioactive species on the surfaces of the primary circuit, are greatly influenced by the physical and chemical properties of these oxide films. The composition and characteristics of the oxide films in turn depend on the applied water chemistry. This work was undertaken in order to collect and evaluate the present views on the structure and behaviour of oxide films formed on iron- and nickel-based materials in aqueous environments. This survey should serve to recognise the areas in which more understanding and research effort is needed. The review begins with a discussion on the bulk oxides of iron, nickel and chromium, as well as their mixed oxides. In addition to bulk oxides, the structure and properties of oxide films forming on pure iron, nickel and chromium and on iron- and nickel-based engineering alloys are considered. General approaches to model the structure and growth of oxide films on metals are discussed in detail. The specific features of the oxide structures, properties and growth at high temperatures are presented with special focus on the relevance of existing models. Finally, the role of oxide films in localised corrosion, oxide breakdown pitting. Stress corrosion cracking and related phenomena is considered. The films formed on the surfaces of iron- and nickel-based alloys in high-temperature aqueous environments generally comprise two layers, i.e. the so-called duplex structure. The inner part is normally enriched in chromium and has a more compact structure, while the outer part is enriched in iron and has a cracked or porous structure. The information collected clearly indicates the effect of the chemical environment on the properties of oxide films growing on metal surfaces

  1. Influence of Trace Elements on Hot Ductility of an Ultra High Purity Invar Alloy

    OpenAIRE

    Perrot-Simonetta, M.; Kobylanski, A.

    1995-01-01

    Like steels, austenitic INVAR alloys Fe-Ni 36 % show a large ductility trough between 500°C and 1100°C. To understand hot brittleness mechanisms and especially trace element effects, synthetic alloys were prepared using ultra-high purity iron and nickel doped with selected amounts of carbon, sulphur, boron, aluminium, and nitrogen. Four kinds of synthetic alloys were studied to establish the intrinsic influence of sulphur, the combined effects of sulphur and precipitates such AlN or BN, and t...

  2. Studies on the Codeposition of SiC Nanopowder with Nickel, Cobalt, and Co-Ni Alloys

    OpenAIRE

    Ewa Rudnik; Sławomir Syrek

    2014-01-01

    Electrodeposition of SiC nanopowder (approximately 120 nm) with nickel, cobalt, and Co-Ni alloy matrix was studied. It was found that particles suspended in the bath affect slightly the reduction of metallic ions. Incorporation of the ceramic particles was governed mainly by the morphology of the matrix surface, while no strict correlation between the amount of cobalt ions adsorbed on the powder and the SiC content in the composites was found. Microhardness of nickel deposits was 585±5 HV, wh...

  3. Corrosion of Alloy 617 in high-temperature gas environments

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, Tsung-Kuang [Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu 300, Taiwan (China); Department of Engineering and System Science, National Tsing Hua University, Hsinchu 300, Taiwan (China); Chang, Hao-Ping [Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu 300, Taiwan (China); Wang, Mei-Ya, E-mail: meywang@mx.nthu.edu.tw [Nuclear Science and Technology Development Center, National Tsing Hua University, Hsinchu 300, Taiwan (China); Yuan, Trai [Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu 300, Taiwan (China); Kai, Ji-Jung [Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu 300, Taiwan (China); Department of Engineering and System Science, National Tsing Hua University, Hsinchu 300, Taiwan (China)

    2014-05-01

    High-temperature gas-cooled reactors (HTGRs) with helium gas as the primary coolant have been considered as one type of the Generation IV nuclear power reactor systems. Several nickel-based superalloys, including Alloy 617, are potential structural materials to serve as pressure boundary components, such as the intermediate heat exchanger (IHX) in an HTGR. Impurities in a helium coolant, such as H{sub 2}O and O{sub 2}, can interact with structural materials at working temperatures of >900 °C, leading to serious degradation on these materials. In addition, defects in IHX surface coatings would allow these species to reach and interact with the external surfaces of these components, leading to similar or even more serious degradation. In this study we investigated the oxidation behavior of Alloy 617 in high-temperature, gaseous environments with various levels of O{sub 2} and H{sub 2}O. A series of general corrosion tests were conducted at test temperatures of 650 °C, 750 °C, 850 °C and 950 °C under various coolant compositions of dry air, 1% O{sub 2}, 10% relative humidity (RH), and 50% RH. Preliminary results showed that the surface morphologies of the Alloy 617 samples exhibited distinct evidence of intergranular corrosion. Compact chromium oxide layers were observed on the sample surfaces. The oxidation mechanisms of this alloy in the designated environments are discussed.

  4. Effect of Metal Primers on Bond Strength of a Composite Resin to Nickel-Chrome Metal Alloy.

    Science.gov (United States)

    Nima, Gabriel; Ferreira, Paulo Vitor Campos; Paula, Andreia Bolzan de; Consani, Simonides; Giannini, Marcelo

    2017-01-01

    This study evaluated the effects of three metal primers and one multi-mode adhesive system on the shear bond strength (SBS) of a flowable composite resin to nickel-chrome metal alloy (Ni-Cr). Ninety plates were cast from Ni-Cr and divided in nine groups (n=10). The surfaces were sandblasted with Al2O3 and primed with three adhesive primers: Alloy Primer (AP), Universal Primer (TP) and RelyX Ceramic Primer (CP), and a multi-mode adhesive (Scotchbond Universal, SU). The Adper Single Bond Plus (SB) and SU adhesives were also combined with adhesive primers. Control group did not have any surface treatment. The groups were: AP, AP+SB, AP+SU, TP+SB, TP+SU, CP+SB, CP+SU and SU. Composite cylinders were built on alloy surface. After 24 h, half the specimens were subjected to SBS and the other half to thermal cycling before testing. Data were analyzed by two-way ANOVA and Tukey's test (a=0.05). Failure modes were assessed by SEM observation. Higher SBS were obtained with AP and TP combined with adhesives at 24 h and the lowest one for control group. Thermocycling reduced SBS for AP, CP+SU and SU. Combination between TP and SU resulted in the highest SBS after the thermocycling. TP groups showed all types of failures and high incidence of mixed failures. The use of AP and UP metal primers before application of SU and SB adhesive systems increased the SBS of composite to Ni-Cr. These combinations between metal primers and adhesives had the highest SBS after thermocycling.

  5. Fireside corrosion of nickel base alloys in future 700 C coal fired power plants; Rauchgasseitige Korrosion von Nickelbasislegierungen fuer zukuenftige 700 C-Dampfkraftwerke

    Energy Technology Data Exchange (ETDEWEB)

    Luettschwager, Frank

    2011-09-27

    Coal is still the most important energy source in Germany. In 2009 it produced 42.9 % of the overall German electrical power. Coal is available world-wide in large quantities and can be delivered economically. One of the possible ways to reduce CO{sub 2} pollution is the increase of efficiency of coal fired power plants, which requires steam conditions of up to 700 C - 730 C and 350 bar. Because many German power units will reach the end of their technical lifespan in a few years or the following decade, one will have the possibility to build up modern types of power plants with increased efficiency of more than 50 %. Some international standards (European Pressure Equipment Directive or ASME Boiler and Pressure Vessel Code) require 100 000 hour creep rupture strength of 100 MPa at 750 C. Therefore, nickel base alloys are in the focus of material qualification processes. Nickel base alloys are well investigated due to their hot corrosion behaviour. It is known that sodium sulphate may generate hot corrosion on those alloys at temperatures above its melting point of 884 C. On nickel base alloys an eutectic mixture of nickel sulphate and sodium sulphate with a melting point of 671 C can be generated, which leads to accelerated corrosion. This work examines, whether the high amount of sulphur and alkali metals will induce hot corrosion at the estimated working temperature on devices manufactured from nickel base alloy. Two synthetic coal ash deposits, according to the chemical composition of hard coal and lignite, and typical flue gases with and without sulphur dioxide were blended of pure agents. The reactions of the deposits with heater tubes' materials and synthetic flue gases are examined in the temperature range from 650 C to 800 C and different time ranges up to 2000 hours. The corroded specimen are examined with SEM/EDX to identify relevant corrosion products and determine the corrosivity of deposited compounds. Deposits increase the corrosion rate of

  6. [LONG-SEGMENTAL TRACHEA REPLACEMENT USING NICKEL-TITANIUM ALLOY STENT WRAPPED WITH AUTOLOGOUS PERICARDIUM].

    Science.gov (United States)

    Luo, Yuekui; Guo, Pengming; Li, Bin; Song, Tieniu; Yu, Lixin; Zhang, Jianhua; Wang, Cheng; Jiang, Peng

    2015-11-01

    To perfect the surgical process that trachea could be reconstructed by nickel-titanium (Ni- Ti) alloy stent wrapped with autologous pericardium, and to evaluate the effectiveness and observe the complications. In the experiment, twelve healthy Bama suckling pigs with weight of 18-25 kg were selected. The pericardium was harvested to cover the Ni-Ti alloy stent. The compound artificial trachea was used to reconstruct long-segmental (6 cm) trachea defect. The effectiveness, complications, the properties, and growth rate of the new mucosa of the artificial trachea lumen were observed. Of 12 pigs, 2 died soon because of hemorrhage and infection, respectively; 7 died at 2-4 months after operation because of hyperplasia at the middle section and blockage of phlegm plug; 3 survived after 42 weeks postoperatively, but accompanied with dyspnea symptom. At 1, 2, 3, 4, and 5 months after operation, the average crawl length of the new trachea mucosa was 1, 3, 5, 7, and 10 mm, respectively; the occurrence rates of anastomotic stenosis were 0 (0/10), 0 (0/9), 0 (0/4), 33.3% (1/3), and 33.3% (1/3) respectively; and the occurrence rates of scar hyperplasia in the middle of lumen were 20% (2/10), 66.7% (6/9), 75.0% (3/4), 66.7% (2/3), and 100% (3/3), respectively. At 7 months postoperatively, the bronchoscopy examination showed that the scar in central part of artificial trachea had the trends of stagnation, softening, and narrowing, and respiratory symptom had the trend of slight ease. Hyperplasia tissue could be found in central part of artificial trachea by autopsy and was verified to be fiber cells and necrotic tissue by pathology examination. Ni-Ti alloy stent with autologous pericardium can insure that the reconstructed tracheal lumen is unobstructed, and support the trachea epithelium regeneration; the main factors of the death of the

  7. Progress in High-Entropy Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Michael C

    2013-12-01

    Strictly speaking, high-entropy alloys (HEAs) refer to single-phase, solid-solution alloys with multiprincipal elements in an equal or a near-equal molar ratio whose configurational entropy is tremendously high. This special topic was organized to reflect the focus and diversity of HEA research topics in the community.

  8. 3D printing of high-strength aluminium alloys

    Science.gov (United States)

    Martin, John H.; Yahata, Brennan D.; Hundley, Jacob M.; Mayer, Justin A.; Schaedler, Tobias A.; Pollock, Tresa M.

    2017-09-01

    Metal-based additive manufacturing, or three-dimensional (3D) printing, is a potentially disruptive technology across multiple industries, including the aerospace, biomedical and automotive industries. Building up metal components layer by layer increases design freedom and manufacturing flexibility, thereby enabling complex geometries, increased product customization and shorter time to market, while eliminating traditional economy-of-scale constraints. However, currently only a few alloys, the most relevant being AlSi10Mg, TiAl6V4, CoCr and Inconel 718, can be reliably printed; the vast majority of the more than 5,500 alloys in use today cannot be additively manufactured because the melting and solidification dynamics during the printing process lead to intolerable microstructures with large columnar grains and periodic cracks. Here we demonstrate that these issues can be resolved by introducing nanoparticles of nucleants that control solidification during additive manufacturing. We selected the nucleants on the basis of crystallographic information and assembled them onto 7075 and 6061 series aluminium alloy powders. After functionalization with the nucleants, we found that these high-strength aluminium alloys, which were previously incompatible with additive manufacturing, could be processed successfully using selective laser melting. Crack-free, equiaxed (that is, with grains roughly equal in length, width and height), fine-grained microstructures were achieved, resulting in material strengths comparable to that of wrought material. Our approach to metal-based additive manufacturing is applicable to a wide range of alloys and can be implemented using a range of additive machines. It thus provides a foundation for broad industrial applicability, including where electron-beam melting or directed-energy-deposition techniques are used instead of selective laser melting, and will enable additive manufacturing of other alloy systems, such as non-weldable nickel

  9. 3D printing of high-strength aluminium alloys.

    Science.gov (United States)

    Martin, John H; Yahata, Brennan D; Hundley, Jacob M; Mayer, Justin A; Schaedler, Tobias A; Pollock, Tresa M

    2017-09-20

    Metal-based additive manufacturing, or three-dimensional (3D) printing, is a potentially disruptive technology across multiple industries, including the aerospace, biomedical and automotive industries. Building up metal components layer by layer increases design freedom and manufacturing flexibility, thereby enabling complex geometries, increased product customization and shorter time to market, while eliminating traditional economy-of-scale constraints. However, currently only a few alloys, the most relevant being AlSi10Mg, TiAl6V4, CoCr and Inconel 718, can be reliably printed; the vast majority of the more than 5,500 alloys in use today cannot be additively manufactured because the melting and solidification dynamics during the printing process lead to intolerable microstructures with large columnar grains and periodic cracks. Here we demonstrate that these issues can be resolved by introducing nanoparticles of nucleants that control solidification during additive manufacturing. We selected the nucleants on the basis of crystallographic information and assembled them onto 7075 and 6061 series aluminium alloy powders. After functionalization with the nucleants, we found that these high-strength aluminium alloys, which were previously incompatible with additive manufacturing, could be processed successfully using selective laser melting. Crack-free, equiaxed (that is, with grains roughly equal in length, width and height), fine-grained microstructures were achieved, resulting in material strengths comparable to that of wrought material. Our approach to metal-based additive manufacturing is applicable to a wide range of alloys and can be implemented using a range of additive machines. It thus provides a foundation for broad industrial applicability, including where electron-beam melting or directed-energy-deposition techniques are used instead of selective laser melting, and will enable additive manufacturing of other alloy systems, such as non-weldable nickel

  10. Accelerated Degradation Test and Predictive Failure Analysis of B10 Copper-Nickel Alloy under Marine Environmental Conditions

    OpenAIRE

    Bo Sun; Tianyuan Ye; Qiang Feng; Jinghua Yao; Mumeng Wei

    2015-01-01

    This paper studies the corrosion behavior of B10 copper-nickel alloy in marine environment. Accelerated degradation test under marine environmental conditions was designed and performed based on the accelerated testing principle and the corrosion degradation mechanism. With the prolongation of marine corrosion time, the thickness of Cu2O film increased gradually. Its corrosion product was Cu2(OH)3Cl, which increased in quantity over time. Cl− was the major factor responsible for the marine c...

  11. Characteristics of nickel and iron diffusion in molten lead–17lithium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Yun, E-mail: gao.y.ad@m.titech.ac.jp [Tokyo Institute of Technology, 2-12-1-N1-18, Ookayama, Meguro, Tokyo (Japan); Takahashi, Minoru; Nomura, Masao [Tokyo Institute of Technology, 2-12-1-N1-18, Ookayama, Meguro, Tokyo (Japan); Nozawa, Takashi [Japan Atomic Energy Agency, 2-166 Oaza-Obuchi-Aza-Omotedate, Rokkasho-mura, Aomori (Japan)

    2016-11-01

    Highlights: • The characteristics of nickel (Ni) and iron (Fe) diffusion in molten lead–17lithium (Pb–17Li) alloy were investigated experimentally with the long capillary method. • The chromatography was adopted to measure the concentration distributions of Ni and Fe in the diffusing specimens by ICP-MS. • Arrhenius correlations of diffusion coefficient of both impurities in Pb–17Li were obtained. - Abstract: Diffusion characteristics of transition metals – nickel (Ni) and iron (Fe) diffusion in the molten lead–17lithium (Pb–17Li) were investigated experimentally under the argon atmosphere in the temperature range from 300 °C to 600 °C by using the long capillary method. The axial concentration distributions of Ni and Fe in Pb–17Li specimens were measured by ICP-MS, and the diffusion coefficients of Ni and Fe were determined based on the Fick's second law. The Arrhenius correlations of diffusion coefficient of Ni and Fe were obtained as D{sub Ni} =7.37 × 10{sup −5}exp (−4.66 × 10{sup 3}/RT) (300 °C ≤ T ≤ 450 °C) [cm{sup 2}/s], D{sub Fe} =3.21 × 10{sup −4}exp (−2.64 × 10{sup 4}/RT) (450 °C ≤ T ≤ 600 °C) [cm{sup 2}/s]. It is found that the diffusion coefficient of Ni is one order magnitude bigger than that of Fe in Pb–17Li. The diffusion coefficient of Fe in Pb–17Li was approximately in the same order as that in lead–bismuth eutectic reported by authors.

  12. Influence of Chemical Composition on Rupture Properties at 1200 Degrees F. of Forged Chromium-Cobalt-Nickel-Iron Base Alloys in Solution-Treated and Aged Condition

    Science.gov (United States)

    Reynolds, E E; Freeman, J W; White, A E

    1951-01-01

    The influence of systematic variations of chemical composition on rupture properties at 1200 degrees F. was determined for 62 modifications of a basic alloy containing 20 percent chromium, 20 percent nickel, 20 percent cobalt, 3 percent molybdenum, 2 percent tungsten, 1 percent columbium, 0.15 percent carbon, 1.7 percent manganese, 0.5 percent silicon, 0.12 percent nitrogen and the balance iron. These modifications included individual variations of each of 10 elements present and simultaneous variations of molybdenum, tungsten, and columbium. Laboratory induction furnace heats were hot-forged to round bar stock, solution-treated at 2200 degrees F., and aged at 1400 degrees F. The melting and fabrication conditions were carefully controlled in order to minimize all variable effects on properties except chemical composition. Information is presented which indicates that melting and hot-working conditions play an important role in high-temperature properties of alloys of the type investigated.

  13. Copper Alloy For High-Temperature Uses

    Science.gov (United States)

    Dreshfield, Robert L.; Ellis, David L.; Michal, Gary

    1994-01-01

    Alloy of Cu/8Cr/4Nb (numbers indicate parts by atom percent) improved over older high-temperature copper-based alloys in that it offers enhanced high temperature strength, resistance to creep, and ductility while retaining most of thermal conductivity of pure copper; in addition, alloy does not become embrittled upon exposure to hydrogen at temperatures as high as 705 degrees C. Designed for use in presence of high heat fluxes and active cooling; for example, in heat exchangers in advanced aircraft and spacecraft engines, and other high-temperature applications in which there is need for such material. High conductivity and hardness of alloy exploited in welding electrodes and in high-voltage and high-current switches and other applications in which wear poses design problem.

  14. Development of high performance ODS alloys

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Lin; Gao, Fei; Garner, Frank

    2018-01-29

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

  15. Influence of preparation method on supported Cu-Ni alloys and their catalytic properties in high pressure CO hydrogenation

    DEFF Research Database (Denmark)

    Wu, Qiongxiao; Eriksen, Winnie L.; Duchstein, Linus Daniel Leonhard

    2014-01-01

    (50 bar CO and 50 bar H2). These alloy catalysts are highly selective (more than 99 mol%) and active for methanol synthesis; however, loss of Ni caused by nickel carbonyl formation is found to be a serious issue. The Ni carbonyl formation should be considered, if Ni-containing catalysts (even...... in alloyed form) are used under conditions with high partial pressure of CO. This journal is © The Royal Society of Chemistry....

  16. The use of stainless steel and nickel alloys as low-cost cathodes in microbial electrolysis cells

    KAUST Repository

    Selembo, Priscilla A.

    2009-05-01

    Microbial electrolysis cells (MECs) are used to produce hydrogen gas from the current generated by bacteria, but low-cost alternatives are needed to typical cathode materials (carbon cloth, platinum and Nafion™). Stainless steel A286 was superior to platinum sheet metal in terms of cathodic hydrogen recovery (61% vs. 47%), overall energy recovery (46% vs. 35%), and maximum volumetric hydrogen production rate (1.5 m3 m-3 day-1 vs. 0.68 m3 m-3 day-1) at an applied voltage of 0.9 V. Nickel 625 was better than other nickel alloys, but it did not perform as well as SS A625. The relative ranking of these materials in MEC tests was in agreement with cyclic voltammetry studies. Performance of the stainless steel and nickel cathodes was further increased, even at a lower applied voltage (0.6 V), by electrodepositing a nickel oxide layer onto the sheet metal (cathodic hydrogen recovery, 52%, overall energy recovery, 48%; maximum volumetric hydrogen production rate, 0.76 m3 m-3 day-1). However, performance of the nickel oxide cathodes decreased over time due to a reduction in mechanical stability of the oxides (based on SEM-EDS analysis). These results demonstrate that non-precious metal cathodes can be used in MECs to achieve hydrogen gas production rates better than those obtained with platinum. © 2009 Elsevier B.V. All rights reserved.

  17. The French regulatory experience and views on nickel-base alloy PWSCC prevention and treatment

    Energy Technology Data Exchange (ETDEWEB)

    Turluer, G.; Cattiaux, G.; Monnot, B. [Institut de Radioprotection et de Surete Nucleaire, IRSN, 92 - Fontenay aux Roses (France); Emond, D.; Reuchet, J.; Chartier, Ph. [Direction Generale de la Surete Nucleaire et de la Radioprotection, 75 - Paris (France)

    2003-10-01

    This paper presents the experience feedback and views of the French Regulatory Authority (ASN) and of the technical support institute (IRSN) on PWSCC prevention since the initiation in 1989 of the 'Inconel Zones Review' requested by ASN to Electricite de France (EDF), the national operator of a fleet of 58 PWRs. This proactive requirement, launched before the discovery, in September 1991, of the only CRDM nozzle leak in France, on Bugey unit 3, was then triggered by the recurrence of many alloy 600 rapid degradations and leaks, world wide, and also in France in the late 1980's, particularly on steam generator tubes and on some pressurizer penetrations. Thus, the ASN requested that EDF, perform a comprehensive (generic) proactive assessment on all the nickel-base alloy components and parts of the main primary circuits, which of course included vessel head penetrations and bottom vessel head penetrations, and some other zones as a first priority. This proactive 'review' did, a minima, include the following tasks and actions: - Update and complete, by an extensive R and D program, the understanding and characterization of the Ni base alloys prone to PWSCC, - Analyze the various materials, metallurgical features, mechanical stresses, and physicochemical conditions of the parts exposed to primary water, in order to predict the occurrence of PWSCC initiation and propagation, - Provide a prioritization of the zones to be inspected, - Implement by improved NDE techniques a practical inspection program on the 58 PWRs, - Prepare and implement any needed mitigation actions as a result of the components conditions assessment. The present paper relates the main features of the French regulatory experience over more than 13 years and recalls the main principles of the assessment, which were applied by ASN. These principles, which are formalized in the current regulation rules revised in 1999, are briefly listed hereunder: - It is based on avoiding and

  18. Effect of residual elements on high performance nickel base ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 28; Issue 4. Effect of residual elements on high performance nickel base superalloys for gas turbines and strategies for manufacture. O P Sinha M Chatterjee V V R S Sarma S N Jha. Volume 28 Issue 4 July 2005 pp 379-382 ...

  19. Nickel nanoparticles: A highly efficient catalyst for one pot synthesis ...

    Indian Academy of Sciences (India)

    Nickel nanoparticles: A highly efficient catalyst for one pot synthesis of tetraketones and biscoumarins. JITENDER M KHURANA. ∗ and KANIKA VIJ. Department of Chemistry, University of Delhi, Delhi 110 007, India e-mail: jmkhurana1@yahoo.co.in. MS received 18 March 2011; revised 17 November 2011; accepted 20 ...

  20. Survey of degradation modes of four nickel-chromium-molybdenum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gdowski, G.E. [KMI Energy Services, Livermore, CA (United States)

    1991-03-01

    This report examines the degradation modes of four Ni-Cr-Mo alloys under conditions relevant to the Yucca Mountain Site Characterization Project (YMP). The materials considered are Alloys C-276, C-4, C-22, and 625 because they have desirable characteristics for the conceptual design (CD) of the high-level radioactive-waste containers presented in the YMP Site Characterization Plan (SCP). The types of degradation covered in this report are general corrosion; localized corrosion, including pitting and crevice corrosion; stress corrosion cracking in chloride environments; hydrogen embrittlement (HE); and undesirable phase transformations due to a lack of phase stability. Topics not specifically addressed are welding concerns and microbiological corrosion. The four Ni-Cr-Mo alloys have excellent corrosion resistance in chloride environments such as seawater as well as in more aggressive environments. They have significantly better corrosion resistance than the six materials considered for the CD waste container in the YMP SCP. (Those six materials are Types 304L and 3161L stainless steels, Alloy 825, unalloyed copper, Cu(70)-Ni(30), and 7% aluminum bronze.) In seawater, the Ni-Cr-Mo alloys have negligible general corrosion rates and show little evidence of localized corrosion. The four base materials of these alloys are expected to have nearly indistinguishable corrosion resistance in the YMP environments. The strength requirements of the SCP-CD waste container are met by these materials in the annealed condition; in this condition, they are highly resistant to HE. Historically, HE has been noted when these materials have been strengthened (cold-worked) and used in sour gas (H{sub 2}S and CO{sub 2}) well service -- conditions that are not expected for the YMP. Metallurgical phase stability may be a concern under conditions favoring (1) the formation of intermetallics and carbides, and (2) microstructural ordering.

  1. Standard Test Methods for Detecting Susceptibility to Intergranular Corrosion in Wrought, Nickel-Rich, Chromium-Bearing Alloys

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 These test methods cover two tests as follows: 1.1.1 Method A, Ferric Sulfate-Sulfuric Acid Test (Sections 3-10, inclusive)—This test method describes the procedure for conducting the boiling ferric sulfate—50 % sulfuric acid test which measures the susceptibility of certain nickel-rich, chromium-bearing alloys to intergranular corrosion (see Terminology G 15), which may be encountered in certain service environments. The uniform corrosion rate obtained by this test method, which is a function of minor variations in alloy composition, may easily mask the intergranular corrosion components of the overall corrosion rate on alloys N10276, N06022, N06059, and N06455. 1.1.2 Method B, Mixed Acid-Oxidizing Salt Test (Sections 11-18, inclusive)—This test method describes the procedure for conducting a boiling 23 % sulfuric + 1.2 % hydrochloric + 1 % ferric chloride + 1 % cupric chloride test which measures the susceptibility of certain nickel-rich, chromium-bearing alloys to display a step function increa...

  2. Miniature High Force, Long Stroke Linear Shape Memory Alloy Actuators Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Shape Memory Alloys (SMAs) are metal alloys (of Nickel-Titanium, for example) that can change their shape when heated. When drawn and processed in wire form, the...

  3. Miniature High Force, Long Stroke Linear Shape Memory Alloy Actuators Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Shape Memory Alloys (SMAs) are metal alloys (Nickel-Titanium, for example) that change shape when heated. When drawn and processed in wire form, the shape change is...

  4. Analysis of the ductility dip cracking in the nickel-base alloy 617mod

    Science.gov (United States)

    Eilers, A.; Nellesen, J.; Zielke, R.; Tillmann, W.

    2017-03-01

    While testing steam leading power plant components made of the nickel-base alloy A617mod at elevated temperatures (700 °C), ductility dip cracking (DDC) was observed in welding seams and their surroundings. In order to clarify the mechanism of crack formation, investigations were carried out on welded specimens made of A617mod. Interrupted tensile tests were performed on tensile specimens taken from the area of the welding seam. To simulate the conditions, the tensile tests were conducted at a temperature of 700 °C and with a low strain rate. Local strain fields at grain boundaries and inside single grains were determined at different deformation states by means of two-dimensional digital image correlation (DIC). Besides the strain fields, local hardnesses (nanoindentation), energy dispersive X-Ray spectroscopy (EDX), and electron backscatter diffraction (EBSD) measurements were performed. Besides information concerning the grain orientation, the EBSD measurement provides information on the coincidence site lattice (CSL) at grain boundaries as well as the Schmid factor of single grains. All results of the analysis methods mentioned above were correlated and compared to each other and related to the crack formation. Among other things, correlations between strain fields and Schmid factors were determined. The investigations show that the following influences affect the crack formation: orientation of the grain boundaries to the direction of the loading, the orientation of the grains to each other (CSL), and grain boundary sliding.

  5. Mechanisms of dwell fatigue crack growth in an advanced nickel disc alloy RR1000

    Directory of Open Access Journals (Sweden)

    Yu S.Y.

    2014-01-01

    Full Text Available RR1000 is one of an advanced class of nickel-based superalloys developed for disc applications. Under one hour dwell fatigue loading, complex crack growth behaviour has been observed especially in a coarse grained version of this alloy. At a temperature of 700 ∘C in air an increase of nearly two orders of magnitude in crack growth rates compared to baseline fatigue crack growth rates may be seen. However for certain microstructural conditions, cracks can also demonstrate retardation following initial acceleration. When using a direct current potential difference (d.c.p.d technique for monitoring crack growth, a damage zone of a few hundred microns is often measured ahead of a fast growing crack. Advanced characterisation techniques including SEM, ECCI and X-ray tomography have been adopted in the current study to understand the observed damage zone and retardation phenomenon. It is found that damage zones measured by d.c.p.d reflect brittle and non-uniform advance of the crack resulting from continuous dynamic or quasi-dynamic fracture of an oxide intrusion ahead of the crack tip during the dwell period. In contrast, cracking of the oxide intrusion is less frequent or even prevented during dwell periods associated with a retarded and slow growing crack. Crack tip stress relaxation plays an important role in dictating whether or not dynamic cracking of the oxide intrusion can be avoided.

  6. Analytic estimation and numerical modeling of actively cooled thermal protection systems with nickel alloys

    Directory of Open Access Journals (Sweden)

    Wang Xinzhi

    2014-12-01

    Full Text Available Actively cooled thermal protection system has great influence on the engine of a hypersonic vehicle, and it is significant to obtain the thermal and stress distribution in the system. So an analytic estimation and numerical modeling are performed in this paper to investigate the behavior of an actively cooled thermal protection system. The analytic estimation is based on the electric analogy method and finite element analysis (FEA is applied to the numerical simulation. Temperature and stress distributions are obtained for the actively cooled channel walls with three kinds of nickel alloys with or with no thermal barrier coating (TBC. The temperature of the channel wall with coating has no obvious difference from the one with no coating, but the stress with coating on the channel wall is much smaller than that with no coating. Inconel X-750 has the best characteristics among the three Ni-based materials due to its higher thermal conductivity, lower elasticity module and greater allowable stress. Analytic estimation and numerical modeling results are compared with each other and a reasonable agreement is obtained.

  7. Fatigue resistance of rotary instruments manufactured using different nickel-titanium alloys: a comparative study.

    Science.gov (United States)

    Plotino, Gianluca; Testarelli, Luca; Al-Sudani, Dina; Pongione, Gianlcarlo; Grande, Nicola M; Gambarini, Gianluca

    2014-01-01

    The aim of this study was to investigate whether cyclic fatigue resistance is increased for Controlled Memory (CM) Nickel-Titanium (NiTi) instruments, compared to instruments produced using traditional NiTi and instruments produced using M-Wire alloy. Two groups of NiTi endodontic instruments consisting of identical instrument sizes (constant 0.06 taper and 0.25 tip diameter and constant 0.04 taper and 0.40 tip diameter) were tested: group A compared Hyflex™ CM, Vortex ™ and ProFile ™ size 25 and 0.06 taper and group B compared Hyflex™ CM, Vortex™ and ProFile™ size 40 and 0.04 taper. 10 files from each different subgroup were tested for cyclic fatigue resistance. Mean and standard deviations of the Number of Cycles to Failure (NCF) were calculated for each group and data were statistically analysed (p 0.05) was noted between Vortex™ and ProFile™ in the tested sizes. The new manufacturing process involving memory shape heat treatment produced new NiTi rotary files (Hyflex™ CM) significantly more resistant to fatigue than instruments produced with other proprietary methods of treatment (Vortex™) and with the traditional NiTi grinding process (ProFile™).

  8. Torsional fatigue resistance of pathfinding instruments manufactured from several nickel-titanium alloys.

    Science.gov (United States)

    Alcalde, M P; Duarte, M A H; Bramante, C M; Tanomaru-Filho, M; Vasconcelos, B C; Só, M V R; Vivan, R R

    2017-11-24

    To evaluate the torsional properties of pathfinding nickel-titanium (NiTi) rotary instruments manufactured from several NiTi alloys, ProGlider (M-wire), Hyflex GPF (conventional NiTi Wire and controlled memory wire), Logic (conventional NiTi wire and controlled memory wire) and Mtwo (conventional NiTi wire). A total of 56 NiTi instruments from Glidepath rotary systems (n = 8) were used: Logic (size 25, .01 taper), Logic CM (size 25, .01 taper), ProGlider (size 16, .02 taper), Hyflex GPF (size 15, .01 taper), Hyflex GPF CM (size 15, .02 taper; size 20, .02 taper) and Mtwo (size 10, .04 taper). The torsion tests were performed based on ISO 3630-1 (1992). Three millimetres of each instrument tip was clamped to a small load cell by a lever arm linked to the torsion axis. Data were analysed using a one-way analysis of variance (anova) and Tukey test with a significance level at a = 5%. The Logic size 25, .01 taper had significantly higher torsional strength values (P Hyflex GPF size 15, .01 taper and size 15, .02 taper (P Hyflex GPF size 15, .01 taper and size 15, .02 taper (P Hyflex GPF groups (size 15, .01 taper; size 15, .02 taper; size 20, .02 taper). In relation to the angle of rotation, Logic CM size 25, .01 taper and Hyflex GPF size 15, .01 taper had the highest angle values (P < 0.05). The ProGlider had the lowest angle values in comparison with all the groups (P < 0.05) followed by Mtwo size 10, .04 taper. The Logic size 25, .01 taper had significantly higher angle of rotation values than ProGlider and Mtwo size 10, .04 taper (P < 0.05). The Logic size 25, .01 taper instrument made of conventional NiTi alloy had the highest torsional strength of all instruments tested. In addition, the ProGlider instrument manufactured from M-Wire alloy had the lowest angle of rotation to fracture in comparison with the other instruments. © 2017 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  9. The Effect of Load-Line Displacement Rate on the SCC Growth Rate of Nickel Alloys and Mechanistic Implications

    Energy Technology Data Exchange (ETDEWEB)

    D Morton

    2005-10-19

    A key set of SCC growth experiments was designed to test the hypothesis that deformation/creep is the rate controlling step in LPSCC. These tests were performed on Alloy X-750 AH compact tension specimens at a various constant displacement rates. The deformation/creep rate within the crack tip zone is proportional to the test displacement rate. If crack growth rates were observed to increase with the load-line displacement rate, then this would indicate that deformation/creep is a critical SCC mechanism process. However, results obtained from the load-line displacement tests did not find X-750 AH SCC growth rate to be dependent on the position rate and therefore do not support the assumption that deformation/creep is the rate controlling process in LPSCC. The similarities between the SCC response of X-750, Alloy 600 and EN82H suggests that it is likely that the same SCC process is occurring for all these alloys (i.e., the same rate controlling step) and that deformation based models are also inappropriate for Alloy 600 and EN82H. The strong temperature and coolant hydrogen dependencies exhibited by these alloys make it more likely that nickel alloy LPSCC is controlled by an environmental or corrosion driven process.

  10. Nickel and cobalt release from metal alloys of tools--a current analysis in Germany.

    Science.gov (United States)

    Kickinger-Lörsch, Anja; Bruckner, Thomas; Mahler, Vera

    2015-11-01

    The former 'EU Nickel Directive' and, since 2009, the REACH Regulation (item 27 of Annex XVII) do not include all metallic objects. The nickel content of tools is not regulated by the REACH Regulation, even if they may come into in prolonged contact with the skin. Tools might be possible sources of nickel and cobalt sensitization, and may contribute to elicitation and maintenance of hand eczema. To perform a current analysis of the frequency of nickel or cobalt release from new handheld tools purchased in Germany. Six hundred unused handheld tools from the German market were investigated with the dimethylglyoxime test for nickel release and with disodium-1-nitroso-2-naphthol-3,6-disulfonate solution for cobalt release. Nickel release was detected in 195 of 600 (32.5%) items, and cobalt in only six (1%) of them. Positive nickel results were nearly twice as frequent in tools 'made in Germany' than in tools without a mark of origin. Tools made in other European countries did not release nickel. Cobalt release was only found in pliers and a saw. A correlation was found between price level and nickel release. Among toolkits, 34.2% were inhomogeneous concerning nickel release. The German market currently provides a large number of handheld tools that release nickel, especially tools 'made in Germany'. For consumer protection, it seems appropriate to include handheld tools in the REACH Regulation on nickel. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  11. Effect of environmental and stress intensity factors on IGA/SCC of nickel-base alloy. Nickel ki gokin no ryukai fushoku no hassei shinten ni oyobosu kankyo oyobi oryoku inshi no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Hirano, H.; Kawamura, H. (Central Research Institute of Electric Power Industry, Tokyo (Japan))

    1993-12-25

    Test was conducted on the intergranular attack (IGA) and stress corrosion cracking (SCC) of nickel-base alloy (inconel alloy 600) used for the PWR steam generator heat transfer tubes. The conducted items of test were U-bending test (IGA/SCC generation test with U-bending specimens), double cantilever beam (DCB) test (IGA/SCC generation test with DCB specimens), slow strain rate test (SSRT) and steam generator (SG) model boiler test (boiling/heat transfer/corrosion test by model boiler). The result was as follows: In the high acidity or high alkalinity aqueous solution, the film is unstable on the alloy surface, and the IGA/SCC is generated under the existence of stress. From the result of stress analysis, it was revealed that with an increase in number of long cracks, the stress intensity factor drops. Even with an increase in number of short cracks, the stress intensity factor does not change. In the region (0 to 120kg/mm[sup 3/2]) of stress intensity factor acting on the heat transfer tube, there exists no domain where the crack propagates rapidly. From the SG model boiler test, the crack propagation rate was revealed to be as slow as 10[sup -3] to 10[sup -2][mu]m/h. 22 refs., 13 figs., 3 tabs.

  12. Microstructure of Cast Ni-Cr-Al-C Alloy

    OpenAIRE

    Cios G.; Bała P.; Stępień M.; Górecki K.

    2015-01-01

    Nickel based alloys, especially nickel based superalloys have gained the advantage over other alloys in the field of high temperature applications, and thus become irreplaceable at high temperature creep and aggressive corrosion environments, such as jet engines and steam turbines. However, the wear resistance of these alloys is insufficient at high temperatures. This work describes a microstructure of a new cast alloy. The microstructure consists of γ matrix strengthened by γ’ fine precipita...

  13. Cyclic degradation of titanium-tantalum high-temperature shape memory alloys - The role of dislocation activity and chemical decomposition

    OpenAIRE

    Niendorf, T.; Krooß, P.; Somsen, C.; Rynko, R.; Paulsen, A.; Batyrshina, E.; Frenzel, J.; G. Eggeler; Maier, Hans Jürgen

    2015-01-01

    Titanium-tantalum shape memory alloys (SMAs) are promising candidates for actuator applications at elevated temperatures. They may even succeed in substituting ternary nickel-titanium high temperature SMAs, which are either extremely expensive or difficult to form. However, titanium-tantalum alloys show rapid functional and structural degradation under cyclic thermo-mechanical loading. The current work reveals that degradation is not only governed by the evolution of the ω-phase. Dislocation ...

  14. Evaluation of High-temperature Physicochemical Interactions Between the H282Alloy Melt and Ceramic Material of the Crucible

    Directory of Open Access Journals (Sweden)

    Pirowski Z.

    2014-12-01

    Full Text Available Nickel alloys belong to the group of most resistant materials when used under the extreme operating conditions, including chemically aggressive environment, high temperature, and high loads applied over a long period of time. Although in the global technology market one can find several standard cast nickel alloys, the vast majority of components operating in machines and equipment are made from alloys processed by the costly metalworking operations. Analysis of the available literature and own studies have shown that the use of casting technology in the manufacture of components from nickel alloys poses a lot of difficulty. This is due to the adverse technological properties of these alloys, like poor fluidity, high casting shrinkage, and above all, high reactivity of liquid metal with the atmospheric air over the bath and with the ceramic material of both the crucible and foundry mold. The scale of these problems increases with the expected growth of performance properties which these alloys should offer to the user.

  15. Intrusion features of a high-speed striker of a porous tungsten-based alloy with a strengthening filler in a steel barrier

    Science.gov (United States)

    Ishchenko, A. N.; Afanas'eva, S. A.; Belov, N. N.; Burkin, V. V.; Rogaev, K. S.; Sammel', A. Yu.; Skosyrskii, A. B.; Tabachenko, A. N.; Yugov, N. T.

    2017-09-01

    The complex problem of increasing the penetrating power of strikers based on highly porous tungsten composites is considered by improving their strengthening properties by alloying the hardening components under high-speed collision conditions. Using the method of liquid-phase sintering, we fabricated samples of strikers based on a porous WNiFeCo alloy (tungsten + nickel + iron + cobalt), alloyed with tungsten carbide with cobalt (WCCo8) and titanium-tungsten carbide (TiWC). Dynamic tests of the strikers from the developed alloys were carried out at the collision velocity with a steel barrier of the order of 2800 m/s. The penetration depth of the striker based on a porous WNiFeCo alloy doped with tungsten carbides is 30% higher than the penetration depth of a striker of a monolithic WNiFe-90 alloy (tungsten + nickel + iron with a tungsten content of 90%).

  16. Effects of Alloying Elements on Room and High Temperature Tensile Properties of Al-Si Cu-Mg Base Alloys =

    Science.gov (United States)

    Alyaldin, Loay

    In recent years, aluminum and aluminum alloys have been widely used in automotive and aerospace industries. Among the most commonly used cast aluminum alloys are those belonging to the Al-Si system. Due to their mechanical properties, light weight, excellent castability and corrosion resistance, these alloys are primarily used in engineering and in automotive applications. The more aluminum is used in the production of a vehicle, the less the weight of the vehicle, and the less fuel it consumes, thereby reducing the amount of harmful emissions into the atmosphere. The principal alloying elements in Al-Si alloys, in addition to silicon, are magnesium and copper which, through the formation of Al2Cu and Mg2Si precipitates, improve the alloy strength via precipitation hardening following heat treatment. However, most Al-Si alloys are not suitable for high temperature applications because their tensile and fatigue strengths are not as high as desired in the temperature range 230-350°C, which are the temperatures that are often attained in automotive engine components under actual service conditions. The main challenge lies in the fact that the strength of heat-treatable cast aluminum alloys decreases at temperatures above 200°C. The strength of alloys under high temperature conditions is improved by obtaining a microstructure containing thermally stable and coarsening-resistant intermetallics, which may be achieved with the addition of Ni. Zr and Sc. Nickel leads to the formation of nickel aluminide Al3Ni and Al 9FeNi in the presence of iron, while zirconium forms Al3Zr. These intermetallics improve the high temperature strength of Al-Si alloys. Some interesting improvements have been achieved by modifying the composition of the base alloy with additions of Mn, resulting in an increase in strength and ductility at both room and high temperatures. Al-Si-Cu-Mg alloys such as the 354 (Al-9wt%Si-1.8wt%Cu-0.5wt%Mg) alloys show a greater response to heat treatment as a

  17. 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

  18. Effect of cleanser solutions on the color of acrylic resins associated with titanium and nickel-chromium alloys.

    Science.gov (United States)

    Freitas Oliveira Paranhos, Helena de; Bezzon, Osvaldo Luiz; Davi, Letícia Resende; Felipucci, Daniela Nair Borges; Silva, Cláudia Helena Lovato da; Pagnano, Valéria Oliveira

    2014-01-01

    This study evaluated the effect of cleanser solutions on the color of heat-polymerized acrylic resin (HPAR) and on the brightness of dental alloys with 180 immersion trials. Disk-shaped specimens were made with I) commercially pure titanium, II) nickel-chromium-molybdenum-titanium, III) nickel-chromium molybdenum, and IV) nickel-chromium-molybdenum beryllium. Each cast disk was invested in the flasks, incorporating the metal disk into the HPAR. The specimens (n=5) were then immersed in solutions containing: 0.05% sodium hypochlorite, 0.12% chlorhexidine digluconate, 0.500 mg cetylpyridinium chloride, a citric acid tablet, one of two different sodium perborate/enzyme tablets, and water. The color measurements (∆E) of the HPAR were determined by a colorimeter in accordance with the National Bureau of Standards. The surface brightness of the metal was visually examined for the presence of tarnish. The results (ANOVA; Tukey test-α=0.05) show that there was a significant difference between the groups (psodium hypochlorite caused metallic brightness changes in groups II and IV. It can be concluded that the agents had the same effect on the color of the resin and that the metallic alloys are not resistant to the action of 0.05% sodium hypochlorite.

  19. Phonon broadening in high entropy alloys

    Science.gov (United States)

    Körmann, Fritz; Ikeda, Yuji; Grabowski, Blazej; Sluiter, Marcel H. F.

    2017-09-01

    Refractory high entropy alloys feature outstanding properties making them a promising materials class for next-generation high-temperature applications. At high temperatures, materials properties are strongly affected by lattice vibrations (phonons). Phonons critically influence thermal stability, thermodynamic and elastic properties, as well as thermal conductivity. In contrast to perfect crystals and ordered alloys, the inherently present mass and force constant fluctuations in multi-component random alloys (high entropy alloys) can induce significant phonon scattering and broadening. Despite their importance, phonon scattering and broadening have so far only scarcely been investigated for high entropy alloys. We tackle this challenge from a theoretical perspective and employ ab initio calculations to systematically study the impact of force constant and mass fluctuations on the phonon spectral functions of 12 body-centered cubic random alloys, from binaries up to 5-component high entropy alloys, addressing the key question of how chemical complexity impacts phonons. We find that it is crucial to include both mass and force constant fluctuations. If one or the other is neglected, qualitatively wrong results can be obtained such as artificial phonon band gaps. We analyze how the results obtained for the phonons translate into thermodynamically integrated quantities, specifically the vibrational entropy. Changes in the vibrational entropy with increasing the number of elements can be as large as changes in the configurational entropy and are thus important for phase stability considerations. The set of studied alloys includes MoTa, MoTaNb, MoTaNbW, MoTaNbWV, VW, VWNb, VWTa, VWNbTa, VTaNbTi, VWNbTaTi, HfZrNb, HfMoTaTiZr.

  20. Management of long-term and reversible hysteroscopic sterilization: a novel device with nickel-titanium shape memory alloy.

    Science.gov (United States)

    Xu, Bin; Zhu, Ke-an; Xu, Dabao; Aili, Aixingzi

    2014-07-07

    Female sterilization is the second most commonly used method of contraception in the United States. Female sterilization can now be performed through laparoscopic, abdominal, or hysteroscopic approaches. The hysteroscopic sterilization may be a safer option than sterilization through laparoscopy or laparotomy because it avoids invading the abdominal cavity and undergoing general anaesthesia. Hysteroscopic sterilization mainly includes chemical agents and mechanical devices. Common issues related to the toxicity of the chemical agents used have raised concerns regarding this kind of contraception. The difficulty of the transcervical insertion of such mechanical devices into the fallopian tubes has increased the high incidence of device displacement or dislodgment. At present, Essure® is the only commercially available hysteroscopic sterilization device being used clinically. The system is irreversible and is not effective immediately. Our new hysteroscopic sterility system consists of nickel-titanium (NiTi) shape memory alloy and a waterproof membrane. The NiTi alloy is covered with two coatings to avoid toxic Ni release and to prevent stimulation of epithelial tissue growth around the oviducts. Because of the shape memory effect of the NiTi alloy, the device works like an umbrella: it stays collapsed at low temperature before placement and opens by the force of shape memory activated by the body temperature after it is inserted hysteroscopically into the interstitial tubal lumen. The rim of the open device will incise into interstitial myometrium during the process of unfolding. Once the device is fixed, it blocks the tube completely. When the patient no longer wishes for sterilization, the device can be closed by perfusing liquid with low temperature into the uterine cavity, followed by prospective hysteroscopic removal. After the device removal, the fallopian tube will revert to its physiological functions. Currently, experimental and clinical studies are needed

  1. High-temperature performance evaluation of adirectionally solidified nickel-base superalloy

    Science.gov (United States)

    Woodford, D. A.; Stiles, D.

    1997-08-01

    The application of a new approach, design for performance, for high-temperature alloy development, design analysis, and remaining life assessment, based on short-time high-precision testing, is described in this paper. The material tested was a directionally solidified nickel-base alloy, GTD111. It was found that the creep strength at 850 °C was indeed superior to that of a competitive alloy, IN738, but was not necessarily enhanced by the preferred alignment of grain boundaries and crystal orientation. In contrast, the fracture resistance at 800 °C was improved in the longitudinal direction compared with transverse and diagonal orientations in terms of susceptibility to gas phase embrittlement (GPE) by oxygen. Specimens cut transversely and diagonally to the growth direction were more sensitive to GPE than specimens taken from conventionally cast IN738. The new conceptual framework allows account to be taken of GPE and other embrittling phenomena, which may develop in service, leading to rational life management decisions for gas turbine users. Additionally, straightforward design analysis procedures can be developed from the test data, which for the first time allow separate measurements of creep strength and fracture resistance to be used for performance evaluation.

  2. STACKING FAULT ENERGY IN HIGH MANGANESE ALLOYS

    Directory of Open Access Journals (Sweden)

    Eva Mazancová

    2009-04-01

    Full Text Available Stacking fault energy of high manganese alloys (marked as TWIP and TRIPLEX is an important parameter determining deformation mechanism type realized in above mentioned alloys. Stacking fault energy level can be asserted with a gliding of partial and/or full dislocations, b gliding mechanism and twinning deformation process in connection with increasing of fracture deformation level (deformation elongation and with increasing of simultaneously realized work hardening proces., c gliding mechanism and deformation induced e-martensite formation. In contribution calculated stacking fault energies are presented for various chemical compositions of high manganese alloys. Stacking fault energy dependences on manganese, carbon, iron and alluminium contents are presented. Results are confronted with some accessible papers.The aim of work is to deepen knowledge of presented data. The TWIP and TRIPLEX alloys can be held for promissing new automotive materials.

  3. Impact properties of tungsten-based alloys under conditions of high-speed interaction

    Science.gov (United States)

    Afanas'eva, S. A.; Belov, N. N.; Biryukov, Yu. A.; Burkin, V. V.; Ishchenko, A. N.; Martsunova, L. S.; Tabachenko, A. N.; Khabibullin, M. V.; Yugov, N. T.

    2013-04-01

    Some aspects of obtaining alloys of the tungsten-nickel-iron-cobalt (TNIC) system have been investigated by the method of liquid-phase sintering of powder preparations, including those containing nano-size tungsten powders. By varying the initial porosity of the powder preparations, samples of highly porous composites have been obtained. A calculational-experimental method was used to investigate the penetrating power of cylindrical impactors made from TNIC alloys on steel plates. An increase in penetration depth with growth of porosity of the sample has been established in the considered range of impact speeds.

  4. Magnesium-Nickel alloy for hydrogen storage produced by melt spinning followed by cold rolling

    Directory of Open Access Journals (Sweden)

    Daniel Rodrigo Leiva

    2012-10-01

    Full Text Available Severe plastic deformation routes (SPD have been shown to be attractive for short time preparation of magnesium alloys for hydrogen storage, generating refined microstructures and interesting hydrogen storage properties when compared to the same materials processed by high-energy ball milling (HEBM, but with the benefit of higher air resistance. In this study, we present results of a new processing route for Mg alloys for hydrogen storage: rapid solidification followed by cold work. A Mg97Ni3 alloy was processed by melt spinning (MS and by extensive cold rolling (CR. Submitting Mg97Ni3 ribbons between steel plates to cold rolling has shown to be a viable procedure, producing a thin cold welded foil, with little material waste. The as-processed material presents a high level of [002] fiber texture, a sub microcrystalline grain structure with a high density of defects, and also a fine dispersion of Mg2Ni nanoparticles. This refined microstructure allied to the developed texture resulted in enhanced activation and H-sorption kinetics properties.

  5. Corrosion resistance of stainless steel, nickel-titanium, titanium molybdenum alloy, and ion-implanted titanium molybdenum alloy archwires in acidic fluoride-containing artificial saliva: Anin vitrostudy.

    Science.gov (United States)

    Pulikkottil, Venith Jojee; Chidambaram, S; Bejoy, P U; Femin, P K; Paul, Parson; Rishad, Mohamed

    2016-10-01

    (1) To evaluate the corrosion resistance of four different orthodontic archwires and to determine the effect of 0.5% NaF (simulating high fluoride-containing toothpaste of about 2250 ppm) on corrosion resistance of these archwires. (2) To assess whether surface roughness (Ra) is the primary factor influencing the corrosion resistance of these archwires. Four different archwires (stainless steel [SS], nickel-titanium [NiTi], titanium molybdenum alloy [TMA], and ion-implanted TMA) were considered for this study. Surface characteristics were analyzed using scanning electron microscopy, atomic force microscopy (AFM), and energy dispersive spectroscopy. Linear polarization test, a fast electrochemical technique, was used to evaluate the corrosion resistance, in terms of polarization resistance of four different archwires in artificial saliva with NaF concentrations of 0% and 0.5%. Statistical analysis was performed by one-way analysis of variance. The potentiostatic study reveals that the corrosion resistance of low-friction TMA (L-TMA) > TMA > NiTi > SS. AFM analysis showed the surface Ra of TMA > NiTi > L-TMA > SS. This indicates that the chemical composition of the wire is the primary influential factor to have high corrosion resistance and surface Ra is only secondary. The corrosion resistance of all wires had reduced significantly in 0.5% acidic fluoride-containing artificial saliva due to formation of fluoride complex compound. The presence of 0.5% NaF in artificial saliva was detrimental to the corrosion resistance of the orthodontic archwires. Therefore, complete removal of residual high-fluorinated toothpastes from the crevice between archwire and bracket during tooth brushing is mandatory.

  6. Corrosion resistance, surface mechanical properties, and cytocompatibility of plasma immersion ion implantation-treated nickel-titanium shape memory alloys.

    Science.gov (United States)

    Yeung, K W K; Poon, R W Y; Liu, X Y; Ho, J P Y; Chung, C Y; Chu, P K; Lu, W W; Chan, D; Cheung, K M C

    2005-11-01

    Nickel-titanium shape memory alloys are promising materials in orthopedic applications because of their unique properties. However, for prolonged use in a human body, deterioration of the corrosion resistance of the materials becomes a critical issue because of the increasing possibility of deleterious ions released from the substrate to living tissues. We have investigated the use of nitrogen, acetylene, and oxygen plasma immersion ion implantation (PIII) to improve the corrosion resistance and mechanical properties of the materials. Our results reveal that the corrosion resistance and mechanical properties such as hardness and elastic modulus are significantly enhanced after surface treatment. The release of nickel is drastically reduced as compared with the untreated control. In addition, our in vitro tests show that the plasma-treated surfaces are well tolerated by osteoblasts. Among the three types of samples, the best biological effects are observed on the nitrogen PIII samples.

  7. Simulation and Modeling in High Entropy Alloys

    Science.gov (United States)

    Toda-Caraballo, I.; Wróbel, J. S.; Nguyen-Manh, D.; Pérez, P.; Rivera-Díaz-del-Castillo, P. E. J.

    2017-11-01

    High entropy alloys (HEAs) is a fascinating field of research, with an increasing number of new alloys discovered. This would hardly be conceivable without the aid of materials modeling and computational alloy design to investigate the immense compositional space. The simplicity of the microstructure achieved contrasts with the enormous complexity of its composition, which, in turn, increases the variety of property behavior observed. Simulation and modeling techniques are of paramount importance in the understanding of such material performance. There are numerous examples of how different models have explained the observed experimental results; yet, there are theories and approaches developed for conventional alloys, where the presence of one element is predominant, that need to be adapted or re-developed. In this paper, we review of the current state of the art of the modeling techniques applied to explain HEAs properties, identifying the potential new areas of research to improve the predictability of these techniques.

  8. High-temperature alloys for high-power thermionic systems

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Kwang S.; Jacobson, D.L.; D' cruz, L.; Luo, Anhua; Chen, Bor-Ling.

    1990-08-01

    The need for structural materials with useful strength above 1600 k has stimulated interest in refractory-metal alloys. Tungsten possesses an extreme high modulus of elasticity as well as the highest melting temperature among metals, and hence is being considered as one of the most promising candidate materials for high temperature structural applications such as space nuclear power systems. This report is divided into three chapters covering the following: (1) the processing of tungsten base alloys; (2) the tensile properties of tungsten base alloys; and (3) creep behavior of tungsten base alloys. Separate abstracts were prepared for each chapter. (SC)

  9. The Study of the Impact of Surface Preparation Methods of Inconel 625 and 718 Nickel-Base Alloys on Wettability by BNi-2 and BNi-3 Brazing Filler Metals

    Directory of Open Access Journals (Sweden)

    Lankiewicz K.

    2015-04-01

    Full Text Available The article discusses the impact of surface preparation method of Inconel 625 and 718 nickel-base alloys in the form of sheets on wettability of the surface. The results of the investigations of surface preparation method (such as nicro-blasting, nickel plating, etching, degreasing, abrasive blasting with grit 120 and 220 and manually grinding with grit 120 and 240 on spreading of BNi-2 and BNi-3 brazing filler metals, widely used in the aerospace industry in high temperature vacuum brazing processes, are presented. Technological parameters of vacuum brazing process are shown. The macro- and microscopic analysis have shown that nicro-blasting does not bring any benefits of wettability of the alloys investigated.

  10. The Study Of The Impact Of Surface Preparation Methods Of Inconel 625 And 718 Nickel-Base Alloys On Wettability By BNi-2 And BNi-3 Brazing Filler Metals

    Directory of Open Access Journals (Sweden)

    Lankiewicz K.

    2015-06-01

    Full Text Available The article discusses the impact of surface preparation method of Inconel 625 and 718 nickel-base alloys in the form of sheets on wettability of the surface. The results of the investigations of surface preparation method (such as nicro-blasting, nickel plating, etching, degreasing, abrasive blasting with grit 120 and 220 and manually grinding with grit 120 and 240 on spreading of BNi-2 and BNi-3 brazing filler metals, widely used in the aerospace industry in high temperature vacuum brazing processes, are presented. Technological parameters of vacuum brazing process are shown. The macro- and microscopic analysis have shown that nicro-blasting does not bring any benefits of wettability of the alloys investigated.

  11. Surface mechanical properties, corrosion resistance, and cytocompatibility of nitrogen plasma-implanted nickel-titanium alloys: a comparative study with commonly used medical grade materials.

    Science.gov (United States)

    Yeung, K W K; Poon, R W Y; Chu, P K; Chung, C Y; Liu, X Y; Lu, W W; Chan, D; Chan, S C W; Luk, K D K; Cheung, K M C

    2007-08-01

    Stainless steel and titanium alloys are the most common metallic orthopedic materials. Recently, nickel-titanium (NiTi) shape memory alloys have attracted much attention due to their shape memory effect and super-elasticity. However, this alloy consists of equal amounts of nickel and titanium, and nickel is a well known sensitizer to cause allergy or other deleterious effects in living tissues. Nickel ion leaching is correspondingly worse if the surface corrosion resistance deteriorates. We have therefore modified the NiTi surface by nitrogen plasma immersion ion implantation (PIII). The surface chemistry and corrosion resistance of the implanted samples were studied and compared with those of the untreated NiTi alloys, stainless steel, and Ti-6Al-4V alloy serving as controls. Immersion tests were carried out to investigate the extent of nickel leaching under simulated human body conditions and cytocompatibility tests were conducted using enhanced green fluorescent protein mice osteoblasts. The X-ray photoelectron spectroscopy results reveal that a thin titanium nitride (TiN) layer with higher hardness is formed on the surface after nitrogen PIII. The corrosion resistance of the implanted sample is also superior to that of the untreated NiTi and stainless steel and comparable to that of titanium alloy. The release of nickel ions is significantly reduced compared with the untreated NiTi. The sample with surface TiN exhibits the highest amount of cell proliferation whereas stainless steel fares the worst. Compared with coatings, the plasma-implanted structure does not delaminate as easily and nitrogen PIII is a viable way to improve the properties of NiTi orthopedic implants.

  12. Electrodeposition mechanism and corrosion behavior of multilayer nanocrystalline nickel-tungsten alloy

    DEFF Research Database (Denmark)

    Allahyarzadeh, M.H.; Aliofkhazraei, M.; Rouhaghdam, A. Sabour

    2017-01-01

    Multilayer nickel-tungsten coatings were deposited on carbon steel using the pulse reverse current technique. Nickel-tungsten layered structure coatings were developed using the continuous and alternative variation of pulse duty cycle at two specific and fixed values. In these coatings, the multi......Multilayer nickel-tungsten coatings were deposited on carbon steel using the pulse reverse current technique. Nickel-tungsten layered structure coatings were developed using the continuous and alternative variation of pulse duty cycle at two specific and fixed values. In these coatings...

  13. [Effect of recasting on the elastic modulus of metal-ceramic systems from nickel-chromium and cobalt-chromium alloys].

    Science.gov (United States)

    Mirković, Nemanja

    2007-07-01

    Elastic modulus of metal-ceramic systems determines their flexural strenght and prevents damages on ceramics during mastication. Recycling of basic alloys is often a clinical practice, despite the possible effects on the quality of the future metal-ceramic dentures. This research was done to establish recasting effects of nickel-chromium and cobalt-chromium alloys on the elastic modulus of metal-ceramic systems in making fixed partial dentures. The research was performed as an experimental study. Six metal-ceramic samples of nickel-chromium alloy (Wiron 99) and cobalt-chromium alloy (Wirobond C) were made. Alloy residues were recycled through twelve casting generations with the addition of 50% of new alloy on the occasion of every recasting. Three- point bending test was used to determine elastic modulus, recommended by the standard ISO 9693:1999. Fracture load for damaging ceramic layer was recorded on the universal testing machine (Zwick, type 1464), with the speed of 0,05 mm/min. The results of this research revealed significant differences between elasticity modules of metal-ceramic samples in every examined recycle generation. Recasting had negative effect on the elastic modulus of the examined alloys. This research showed the slight linear reduction of elastic modulus up to the 6th generation of recycling. After the 6th recycling there was a sudden fall of elastic modulus. Recasting of nickel-chromium and cobalt-chromium alloys is not recommended because of the reduced elastic modulus of these alloys. Instead of reusing previously recasted alloys, the alloy residues should be returned to the manufacturer.

  14. Progress in Preparation and Research of High Entropy Alloys

    Directory of Open Access Journals (Sweden)

    CHEN Yong-xing

    2017-11-01

    Full Text Available The current high entropy alloys' studies are most in block, powder, coating, film and other areas. There are few studies of high entropy alloys in other areas and they are lack of unified classification. According to the current high entropy alloys' research situation, The paper has focused on the classification on all kinds of high entropy alloys having been researched, introduced the selecting principle of elements, summarized the preparation methods, reviewed the research institutions, research methods and research contents of high entropy alloys, prospected the application prospect of high entropy alloys, put forward a series of scientific problems of high entropy alloys, including less research on mechanism, incomplete performance research, unsystematic thermal stability study, preparation process parameters to be optimized, lightweight high entropy alloys' design, the expansion on the research field, etc, and the solutions have been given. Those have certain guiding significance for the expansion of the application of high entropy alloys subjects in the future research direction.

  15. High-temperature performance of a new nickel-based filler metal for power generation application

    Energy Technology Data Exchange (ETDEWEB)

    Shingledecker, J.; Coleman, K. [Electric Power Research Institute, Charlotte, NC (United States); Siefert, J.; Tanzosh, J. [Babcok and Wilcox Research Center, Barberton, OH (United States); Newell, W. [Euroweld, Mooresville, NC (United States)

    2010-07-01

    A new nickel-based weld filler metal, EPRI P87, has been developed as a superior alternative to ERNiCr-3 for use in dissimilar metal welds (DMW) between ferritic and austenitic materials. EPRI P87 has a low coefficient of thermal expansion more closely matching alloys such as Grade 91 and 92 than other available filler metals. Additionally, the size of the carbon denuded region adjacent to the weld in the heat-affected-zone is minimized/eliminated by proper control of weld metal composition. In this work the high-temperature mechanical behavior of DMWs utilizing EPRI P87 (GTAW and GMAW processes) was characterized through tensile and long-term creep-rupture testing. Microstructure analysis was also conducted on tested specimens to evaluate the HAZ regions and failure modes. Performance of the weld metal and welded joints is discussed and compared with ERNiCr-3 and typical 9%Cr-MoV filler metals. (orig.)

  16. The electrochemical deposition of tin-nickel alloys and the corrosion properties of the coating

    DEFF Research Database (Denmark)

    Jellesen, Morten Stendahl; Møller, Per

    2005-01-01

    The electrodeposition of tin/nickel (65/35 wt%) is a unique coating process because of the deposition of an intermetallic phase of nickel and tin, which cannot be formed by any pyrometallurgical process. From thermodynamic calculations it can be shown that intermetallic phases can be formed throu...

  17. Study of Acidithiobacillus ferrooxidans and enzymatic bio-Fenton process-mediated corrosion of copper-nickel alloy.

    Science.gov (United States)

    Jadhav, U; Hocheng, H

    2016-10-01

    This study presents the corrosion behavior of the copper-nickel (Cu-Ni) alloy in the presence of Acidithiobacillus ferrooxidans (A. ferrooxidans) and glucose oxidase (GOx) enzyme. In both the cases ferric ions played an important role in weight loss and thereby to carry out the corrosion of the Cu-Ni alloy. A corrosion rate of 0.6 (±0.008), 2.11 (±0.05), 3.69 (±0.26), 0.7 (±0.006) and 0.08 (±0.002) mm/year was obtained in 72 h using 9K medium with ferrous sulfate, A. ferrooxidans culture supernatant, A. ferrooxidans cells, GOx enzyme and hydrogen peroxide (H2O2) solution respectively. The scanning electron microscopy (SEM) micrographs showed that a variable extent of corrosion was caused by 9K medium with ferrous sulfate, GOx and A. ferrooxidans cells. An arithmetic average surface roughness (Ra) of 174.78 nm was observed for the control work-piece using optical profilometer. The change in Ra was observed with the treatment of the Cu-Ni alloy using various systems. The Ra for 9K medium with ferrous sulfate, GOx and A. ferrooxidans cells was 374.54, 607.32 and 799.48 nm, respectively, after 24 h. These results suggest that A. ferrooxidans cells were responsible for more corrosion of the Cu-Ni alloy than other systems used.

  18. Reactive oxygen species and oxidative DNA damage mediate the cytotoxicity of tungsten-nickel-cobalt alloys in vitro.

    Science.gov (United States)

    Harris, R M; Williams, T D; Hodges, N J; Waring, R H

    2011-01-01

    Tungsten alloys (WA) have been introduced in an attempt to find safer alternatives to depleted uranium and lead munitions. However, it is known that at least one alloy, 91% tungsten-6% nickel-3% cobalt (WNC-91-6-3), causes rhabdomyosarcomas when fragments are implanted in rat muscle. This raises concerns that shrapnel, if not surgically removable, may result in similar tumours in humans. There is therefore a clear need to develop rapid and robust in vitro methods to characterise the toxicity of different WAs in order to identify those that are most likely to be harmful to human health and to guide development of new materials in the future. In the current study we have developed a rapid visual in vitro assay to detect toxicity mediated by individual WA particles in cultured L6-C11 rat muscle cells. Using a variety of techniques (histology, comet assay, caspase-3 activity, oxidation of 2'7'-dichlorofluorescin to measure the production of reactive oxygen species and whole-genome microarrays) we show that, in agreement with the in vivo rat carcinogenicity studies, WNC-91-6-3 was the most toxic of the alloys tested. On dissolution, it produces large amounts of reactive oxygen species, causes significant amounts of DNA damage, inhibits caspase-3, triggers a severe hypoxic response and kills the cells in the immediate vicinity of the alloy particles within 24h. By combining these in vitro data we offer a mechanistic explanation of the effect of this alloy in vivo and show that in vitro tests are a viable alternative for assessing new alloys in the future. Copyright © 2010 Elsevier Inc. All rights reserved.

  19. An exploratory study of a zirconium-modified, precipitation-strengthened nickel-30 copper alloy

    Science.gov (United States)

    Whittenberger, J. D.

    1974-01-01

    A precipitation-strengthened alloy has been produced through minor additions of zirconium to a base Ni-30Cu alloy. The results of this exploratory study indicate that thermomechanical processing of a solution-treated Ni-30Cu-0.2Zr alloy produced a dispersion of precipitates. The precipitates have been tentatively identified as a Ni5Zr compound. Comparison of the mechanical properties, as determined by testing in air, of the Zr-modified alloy to those of a Ni-30Cu alloy reveals that the precipitation-strengthened alloy has improved tensile properties to 1200 K and improved stress-rupture properties to 1100 K. The oxidation characteristics of the modified alloy appeared to be equivalent to those of the base Ni-30Cu alloy.

  20. Effect of recasting on the elastic modulus of metal-ceramic systems from nickel-chromium and cobalt-chromium alloys

    OpenAIRE

    Mirković Nemanja

    2007-01-01

    Background/Aim. Elastic modulus of metal-ceramic systems determines their flexural strength and prevents damages on ceramics during mastication. Recycling of basic alloys is often a clinical practice, despite the possible effects on the quality of the future metal-ceramic dentures. This research was done to establish recasting effects of nickel-chromium and cobalt-chromium alloys on the elastic modulus of metalceramic systems in making fixed partial dentures. Methods. The research was perform...

  1. Effect of ion-implantation on surface characteristics of nickel titanium and titanium molybdenum alloy arch wires

    Directory of Open Access Journals (Sweden)

    Manu Krishnan

    2013-01-01

    Full Text Available Aim: To evaluate the changes in surface roughness and frictional features of ′ion-implanted nickel titanium (NiTi and titanium molybdenum alloy (TMA arch wires′ from its conventional types in an in-vitro laboratory set up. Materials and Methods: ′Ion-implanted NiTi and low friction TMA arch wires′ were assessed for surface roughness with scanning electron microscopy (SEM and 3 dimensional (3D optical profilometry. Frictional forces were studied in a universal testing machine. Surface roughness of arch wires were determined as Root Mean Square (RMS values in nanometers and Frictional Forces (FF in grams. Statistical Analysis Used: Mean values of RMS and FF were compared by Student′s ′t′ test and one way analysis of variance (ANOVA. Results: SEM images showed a smooth topography for ion-implanted versions. 3D optical profilometry demonstrated reduction of RMS values by 58.43% for ion-implanted NiTi (795.95 to 330.87 nm and 48.90% for TMA groups (463.28 to 236.35 nm from controls. Nonetheless, the corresponding decrease in FF was only 29.18% for NiTi and 22.04% for TMA, suggesting partial correction of surface roughness and disproportionate reduction in frictional forces with ion-implantation. Though the reductions were highly significant at P < 0.001, relations between surface roughness and frictional forces remained non conclusive even after ion-implantation. Conclusion: The study proved that ion-implantation can significantly reduce the surface roughness of NiTi and TMA wires but could not make a similar reduction in frictional forces. This can be attributed to the inherent differences in stiffness and surface reactivity of NiTi and TMA wires when used in combination with stainless steel brackets, which needs further investigations.

  2. Cast Aluminum Alloy for High Temperature Applications

    Science.gov (United States)

    Lee, Jonathan A.

    2003-01-01

    Originally developed by NASA as high performance piston alloys to meet U.S. automotive legislation requiring low exhaust emission, the novel NASA alloys now offer dramatic increase in tensile strength for many other applications at elevated temperatures from 450 F (232 C) to about 750 F (400 C). It is an ideal low cost material for cast automotive components such as pistons, cylinder heads, cylinder liners, connecting rods, turbo chargers, impellers, actuators, brake calipers and rotors. It can be very economically produced from conventional permanent mold, sand casting or investment casting, with silicon content ranging from 6% to 18%. At high silicon levels, the alloy exhibits excellent dimensional stability, surface hardness and wear resistant properties.

  3. Reconstruction of tracheal wall defect with a mesh patch of nickel-titanium shape-memory alloy.

    Science.gov (United States)

    Luo, Jia-Sheng; Cui, Peng-Cheng; Gao, Peng-Fei; Nan, Hou; Liu, Zhi; Sun, Yong-Zhu

    2011-03-01

    We explored the feasibility of reconstructing tracheal wall defects with a mesh patch fashioned from a nickel-titanium shape-memory alloy. A tracheal wall defect was first constructed surgically by resecting the anterior half of the tracheal wall between the second and sixth tracheal rings. The defect was reconstructed in 8 experimental animals by replacing the resected tracheal mucosa and tracheal cartilage with a pedicle skin flap, which was then enclosed in the mesh patch. In 4 control animals, only a pedicle skin flap with strap muscles was used in the reconstruction procedure. The performance of the animals was observed after surgery. At the end of the experiments, the reconstructed segment was harvested for anatomic evaluation. In the experimental group, 1 animal died 5 days after the operation. Endoscopic and anatomic examination of the 7 animals that survived the observation period showed that the reconstructed trachea was stable, with sufficient airway space for breathing. All 4 control animals died after the operation. After observing successful completion of this operation in animals, we successfully used this method to repair a tracheal wall defect in a human victim of a traffic accident. Tracheal defects can be successfully reconstructed by use of a mesh patch of nickel-titanium shape-memory alloy as an extraluminal stent--a method that avoids complications associated with intraluminal stents.

  4. FEATURES OF SPHEROIDIZING MODIFICATION OF HIGH-STRENGTH CAST IRON WITH MASTER ALLOYS BASED ON COPPER

    Directory of Open Access Journals (Sweden)

    A. S. Kalinichenko

    2016-01-01

    Full Text Available The increase of efficiency of modification process for ductile iron is topically, thereby increasing its mechanical and operational properties. For these purposes, in practice, various magnesium containing alloys are used, including «heavy» ones on the basis of Copper and Nickel. The analysis has shown that the application of bulk inoculating alloys based on copper basis were not effectively due to long dissolution period. From this point of view, the interest is high-speed casting, allowing the production of inoculating alloys in the form of strips – chips that are characterized by a low dissolution time and low piroeffekt. The aim of this work is to study the features of structure formation in nodular cast iron using different spheroidizing alloys based on copper. Studies have shown that the transition from the use of briquetted form alloys based on copper and magnesium to the «chips-inoculating alloys» allowed increasing the efficiency of the spheroidizing process. Further improvement in the quality of ductile iron can be achieved by the use in «chip-inoculating alloys» additives of nanosized yttrium oxide powder. 

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

    Science.gov (United States)

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

    1982-01-01

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

  6. Effect of cleanser solutions on the color of acrylic resins associated with titanium and nickel-chromium alloys

    Directory of Open Access Journals (Sweden)

    Helena de Freitas Oliveira Paranhos

    2014-06-01

    Full Text Available This study evaluated the effect of cleanser solutions on the color of heat-polymerized acrylic resin (HPAR and on the brightness of dental alloys with 180 immersion trials. Disk-shaped specimens were made with I commercially pure titanium, II nickel-chromium-molybdenum-titanium, III nickel-chromium molybdenum, and IV nickel-chromium-molybdenum beryllium. Each cast disk was invested in the flasks, incorporating the metal disk into the HPAR. The specimens (n = 5 were then immersed in solutions containing: 0.05% sodium hypochlorite, 0.12% chlorhexidine digluconate, 0.500 mg cetylpyridinium chloride, a citric acid tablet, one of two different sodium perborate/enzyme tablets, and water. The color measurements (∆E of the HPAR were determined by a colorimeter in accordance with the National Bureau of Standards. The surface brightness of the metal was visually examined for the presence of tarnish. The results (ANOVA; Tukey test-α = 0.05 show that there was a significant difference between the groups (p < 0.001 but not among the solutions (p = 0.273. The highest mean was obtained for group III (5.06, followed by group II (2.14. The lowest averages were obtained for groups I (1.33 and IV (1.35. The color changes in groups I, II and IV were slight but noticeable, and the color change was considerable for group III. The visual analysis showed that 0.05% sodium hypochlorite caused metallic brightness changes in groups II and IV. It can be concluded that the agents had the same effect on the color of the resin and that the metallic alloys are not resistant to the action of 0.05% sodium hypochlorite.

  7. Construction of a high-temperature viscosimeter and measurement of the viscosity of melts of the system aluminium-nickel; Aufbau eines Hochtemperaturviskosimeters und Messung der Viskositaet von Schmelzen des Systems Aluminium-Nickel

    Energy Technology Data Exchange (ETDEWEB)

    Kehr, Mirko

    2009-10-29

    The system aluminium-nickel is of importance as a model-system in materials science as well as a basic system for superalloys in technical applications. The knowledge of the thermophysical properties of the system aluminium-nickel has been limited to the areas close to the pure elements mainly related to the high melting temperatures of up to 1638 C. The viscosity, which is one of these thermophysical properties, depends on alloy composition as well as on temperature. The viscosity is of importance as an input parameter in computer simulations and for improving casting processes of metallic alloys. The viscosity of aluminium-nickel melts has been measured only once so far. However, not the whole concentration range of the aluminium-nickel system was covered by these data. In particular the viscosity values of the high melting alloys, which are of technological interest, were unknown. The measurement of the missing values was not possible due to the high melting temperatures using existing viscometers. A new oscillating cup viscometer has been constructed within this work. The viscometer has been tested measuring the viscosity values of pure metals, which are well known in literature. The test measurements have been done at temperatures up to 1800 C. A temperature of 2300 C is achievable with slight modifications. A new software for controlling the device and evaluation of the measured data has been developed. Several working equations for calculating the viscosity have been implemented. Furthermore a new approach has been used for detecting the damping of the oscillation of the pendulum containing the liquid sample. The viscosity of aluminium-nickel melts have been measured successfully. The measured values are in good agreement with the little number of known values. A good agreement with values calculated from diffusion experiments and computer simulations was observed as well. Several models for calculating the viscosity of liquid alloys have been tested and

  8. Assessment of creep rupture data of the nickel alloy 617B

    Energy Technology Data Exchange (ETDEWEB)

    Krein, Ronny [Salzgitter Mannesmann Forschung GmbH, Duisburg (Germany); Kloewer, Jutta [Outokumpu VDM GmbH, Werdohl (Germany); Schraven, Patrik [Salzgitter Mannesmann Stainless Tubes GmbH, Muelheim an der Ruhr (Germany); Knezevic, Vida [Vallourec und Mannesmann Tubes Deutschland GmbH, Duesseldorf (Germany)

    2013-10-01

    Alloy 617B is an advancement of the standard Alloy 617 aiming on improved weldability and better creep behaviour especially for applications at temperatures below 800 C. Against this background, Alloy 617B has been considered as a very promising candidate for the design of Advanced Ultra-Super-Critical power plants operating with steam temperatures of 700 C or even above. However, results show that the creep rupture strength of Alloy 617B is superior to the classical Alloy 617; for higher temperatures the beneficial effect is negligible. (orig.)

  9. X-ray diffraction measurement of residual stress in sol-gel grown lead zirconate titanate thick films on nickel-based super alloy substrate

    Energy Technology Data Exchange (ETDEWEB)

    Hoshyarmanesh, Hamidreza; Nehzat, Naser; Salehi, Mehdi [Isfahan University of Technology, Isfahan (Iran, Islamic Republic of); Ghodsi, Mojtaba [Sultan Qaboos University, Muscat (Oman)

    2015-02-15

    Residual compressive stress of Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} thick films was investigated using residual strains derived from X-ray diffraction patterns. Sin{sup 2}ψ method was applied for the 5, 10 and 15 μm sol-gel derived thick films annealed at 700 .deg. C for 1 hr as high frequency structural health monitoring square-shape transducers of 10 x10 mm, deposited onto the curved nickel-based super alloy substrates. A triaxial model was proposed based on piezoelectric constitutive equations, and Bragg's law at a large diffraction angle (∼89°) was utilized considering the electromechanical coupling factor as well as elastic, dielectric and piezoelectric constants. Thickness variations led to a significant change in residual stress magnitudes delineated from more-accurate triaxial model compared to small angle plane-stress results not considering the piezoelectric coupling effects.

  10. Corrosion Behavior of Nickel Alloy (ASTM A 494 M) Reinforced with Fused SiO2 Chilled Metal Matrix Composites (MMCs) for Marine Applications

    Science.gov (United States)

    Hemanth, Joel, Dr.

    2017-08-01

    This paper presents the results obtained and the discussions made from a series of corrosion experiments involving Nickel alloy (ASTM A 494 M) reinforced with fused SiO2, size of the particles dispersed varies from 80-120 µm and amount of addition varies from 3 to 12 wt.% in steps of 3 wt.%. The resulting chilled MMCs are solidified under the influence of copper chill of 25 mm thickness to study the effect of corrosion behavior. Corrosion resistance was found to increase significantly with increase in SiO2 content in chilled MMCs. Nevertheless, even with high SiO2 content corrosion attack ie., pitting was found to be most severe during the initial stages of each test but it invariably decreased to a very low value in the later stages, due to the formation of an adherent protective layer on the MMCs developed.

  11. High-strength iron aluminide alloys

    Energy Technology Data Exchange (ETDEWEB)

    McKamey, C.G.; Maziasz, P.J.

    1996-06-01

    Past studies have shown that binary Fe{sub 3}Al possesses low creep-rupture strength compared to many other alloys, with creep-rupture lives of less than 5 h being reported for tests conducted at 593{degrees}C and 207 MPa. The combination of poor creep resistance and low room-temperature tensile ductility due to a susceptibility to environmentally-induced dynamic hydrogen embrittlement has limited use of these alloys for structural applications despite their excellent corrosion properties. With regard to the ductility problem, alloy development efforts have produced significant improvements, with ductilities of 10-20% and tensile yield strengths as high as 500 MPa being reported. Likewise, initial improvements in creep resistance have been realized through small additions of Mo, Nb, and Zr.

  12. Development of improved low-strain creep strength in Cabot alloy R-41 sheet. [nickel base sheet alloy for reentry shielding

    Science.gov (United States)

    Rothman, M. F.

    1984-01-01

    The feasibility of improving the low-strain creep properties of a thin gauge nickel base sheet alloy through modified heat treatment or through development of a preferred crystal-lographic texture was investigated. The basic approach taken to improve the creep strength of the material by heat treatment was to increase grain size by raising the solution treatment temperature for the alloy to the range of 1420 K to 1475 K (2100 F to 2200 F). The key technical issue involved was maintenance of adequate tensile ductility following the solutioning of M6C primary carbides during the higher temperature solution treatment. The approach to improve creep properties by developing a sheet texture involved varying both annealing temperatures and the amount of prior cold work. Results identified a heat treatment for alloy R-14 sheet which yields a substantial creep-life advantage at temperatures above 1090 K (1500 F) when compared with material given the standard heat treatment. At the same time, this treatment provides reasonable tensile ductility over the entire temperature range of interest. The mechanical properties of the material given the new heat treatment are compared with those for material given the standard heat treatment. Attempts to improve creep strength by developing a sheet texture were unsuccessful.

  13. Lifetime assessment of thick-walled components made of nickel-base alloys under near-service loading conditions; Lebensdauerbewertung dickwandiger Bauteile aus Nickelbasislegierungen unter betriebsnahen Beanspruchungen

    Energy Technology Data Exchange (ETDEWEB)

    Hueggenberg, Daniel

    2015-11-06

    Until 2050 the renewable energies should provide 80% of the power in Germany according to Renewable Energy law. Due to that reason the conventional power plants are not used for base load, but rather for the supply of average and peak load. The change of the operating mode leads to shorter times at stationary temperatures and the number of faster start-ups/shut-downs of the power plants will increase. As a result of this the components are exposed to an interacting load of creep and fatigue which reduces the lifetimes. The aim of this thesis is the development and verification of a lifetime assessment procedure for components made of the nickel-base alloys Alloy 617 mod. and Alloy 263 under creep fatigue loading conditions based on numerical phenomenological models and on the approaches of different standards/recommendations. The focus lies on two components of the high temperature material test rig II (HWT II), a header made of Alloy 617 mod. and Alloy 263 as well as a formed part made of Alloy 617 mod. For the basis characterization of the HWT II melts, specimens of the Alloy 617 mod. and Alloy 263 are tested in uniaxial tensile tests, (creep-)fatigue tests, creep tests and charpy tests in a temperature range between 20 C and 725 C. From the comparisons of the test results and the material specifications respectively the results of the projects COORETEC DE4, MARCKO DE2 and MARCKO700 no deviations were obvious for both materials with the exception of the creep test results with Alloy 617 mod. material. The creep tests with Alloy 617 mod. material of the HWT II melt show differences regarding the deformation and damage behavior. In addition to the basis characterization tests some complex lab tests for the characterization of the material behavior under creep-fatigue and multiaxial loading conditions were conducted. The developments of the microstructure, the precipitations as well as the structure of dislocations are investigated in the light optical microscope

  14. Transient liquid phase bonding of titanium-, iron- and nickel-based alloys

    Science.gov (United States)

    Rahman, A. H. M. Esfakur

    The operating temperature of land-based gas turbines and jet engines are ever-increasing to increase the efficiency, decrease the emissions and minimize the cost. Within the engines, complex-shaped parts experience extreme temperature, fatigue and corrosion conditions. Ti-based, Ni-based and Fe-based alloys are commonly used in gas turbines and jet engines depending on the temperatures of different sections. Although those alloys have superior mechanical, high temperature and corrosion properties, severe operating conditions cause fast degradation and failure of the components. Repair of these components could reduce lifecycle costs. Unfortunately, conventional fusion welding is not very attractive, because Ti reacts very easily with oxygen and nitrogen at high temperatures, Ni-based superalloys show heat affected zone (HAZ) cracking, and stainless steels show intergranular corrosion and knife-line attack. On the other hand, transient liquid phase (TLP) bonding method has been considered as preferred joining method for those types of alloys. During the initial phase of the current work commercially pure Ti, Fe and Ni were diffusion bonded using commercially available interlayer materials. Commercially pure Ti (Ti-grade 2) has been diffusion bonded using silver and copper interlayers and without any interlayer. With a silver (Ag) interlayer, different intermetallics (AgTi, AgTi2) appeared in the joint centerline microstructure. While with a Cu interlayer eutectic mixtures and Ti-Cu solid solutions appeared in the joint centerline. The maximum tensile strengths achieved were 160 MPa, 502 MPa, and 382 MPa when Ag, Cu and no interlayers were used, respectively. Commercially pure Fe (cp-Fe) was diffusion bonded using Cu (25 m) and Au-12Ge eutectic interlayer (100 microm). Cu diffused predominantly along austenite grain boundaries in all bonding conditions. Residual interlayers appeared at lower bonding temperature and time, however, voids were observed in the joint

  15. High Strength Aluminum Alloy For High Temperature Applications

    Science.gov (United States)

    Lee, Jonathan A. (Inventor); Chen, Po-Shou (Inventor)

    2005-01-01

    A cast article from an aluminum alloy has improved mechanical properties at elevated temperatures. The cast article has the following composition in weight percent: Silicon 6.0-25.0, Copper 5.0-8.0, Iron 0.05-1.2, Magnesium 0.5-1.5, Nickel 0.05-0.9, Manganese 0.05-1.2, Titanium 0.05-1.2, Zirconium 0.05-1.2, Vanadium 0.05-1.2, Zinc 0.05-0.9, Strontium 0.001-0.1, Phosphorus 0.001-0.1, and the balance is Aluminum, wherein the silicon-to-magnesium ratio is 10-25, and the copper-to-magnesium ratio is 4-15. The aluminum alloy contains a simultaneous dispersion of three types of Al3X compound particles (X=Ti, V, Zr) having a LI2 crystal structure, and their lattice parameters are coherent to the aluminum matrix lattice. A process for producing this cast article is also disclosed, as well as a metal matrix composite, which includes the aluminum alloy serving as a matrix containing up to about 60% by volume of a secondary filler material.

  16. Effectiveness of nickel plating in inhibiting atmospheric corrosion of copper alloy contacts

    Energy Technology Data Exchange (ETDEWEB)

    Ernest, T.; Sorensen, R.; Guilinger, T.

    1997-12-31

    A series of tests was run to determine the effect of Ni plating thickness on connector contact resistance. Copper coupons were plated with an electrolytic nickel strike followed by electroless nickel to produce Ni layers of 10, 20, 55 and 100 {micro}in. The coupons were then exposed to a simulated industrial environment. Pore corrosion was observed after the exposure, which correlated with Ni thickness. In a second series of tests, beryllium-copper four-tine contacts with 50 {micro}in of gold plate over electrolytic nickel strike/electroless-nickel plates of varying thickness were exposed the same corrosive environment. Contact resistance of mated pairs was monitored over a two-month period. The degradation in contact resistance correlated with the Ni thickness used in the connectors.

  17. Controllable synthesis of nickel bicarbonate nanocrystals with high homogeneity for a high-performance supercapacitor

    Science.gov (United States)

    Gu, Jianmin; Liu, Xin; Wang, Zhuang; Bian, Zhenpan; Jin, Cuihong; Sun, Xiao; Yin, Baipeng; Wu, Tianhui; Wang, Lin; Tang, Shoufeng; Wang, Hongchao; Gao, Faming

    2017-08-01

    The electrochemical performance of supercapacitors might be associated with the homogeneous structure of the electrode materials. However, the relationship between the degree of uniformity for the electrode materials and the electrochemical performance of the supercapacitor is not clear. Herein, we synthesize two types of nickel bicarbonate nanocrystals with different degrees of uniformity to investigate this relationship. As the electroactive material, the nickel bicarbonate nanocrystals with a homogeneous structure could provide a larger space and offer more exposed atoms for the electrochemical reaction than the nanocrystals with a heterogeneous structure. The homogeneous nickel bicarbonate nanocrystals exhibit better electrochemical performance and show excellent specific capacitance (1596 F g-1 at 2 A g-1 and 1260 F g-1 at 30 A g-1), which is approximately twice that of the heterogeneous nickel bicarbonate nanocrystals. The cycling stability for the homogeneity (˜80%) is higher than the inhomogeneity (˜61%) at a high current density of 5 A g-1.

  18. Development of high-temperature corrosion-resistant alloys and heat-treatment regimes for components placed in the hot section of stationary gas turbines

    Science.gov (United States)

    Zvezdin, Yu. I.; Kotov, Yu. V.; Kats, E. L.; Lubenets, V. P.; Spiridonov, E. V.; Konter, M. L.

    1991-06-01

    New single-crystal alloys for the blades of gas turbines, highly corrosion-resistant alloys for guide vanes and combustion chambers, and low-cost alloys for the gears of turbine compressors have been developed and implemented. In term sof the set of properties, the new alloys are superior to foreign alloys for stationary turbines. A computer-aided design system for alloys with a given level of properties has been created for the development of a new generation of high-temperature nickel alloys. Special heat-treatment regimes, which make it possible to combine heat treatment with the production cycle involving the application of plasmas protective coatings and to achieve the combination of basic mechanical properties that is optimal for a specific component have been developed as applies to specific operating conditions of turbine components.

  19. HighP–TNano-Mechanics of Polycrystalline Nickel

    Directory of Open Access Journals (Sweden)

    Shen TD

    2007-01-01

    Full Text Available AbstractWe have conducted highP–Tsynchrotron X-ray and time-of-flight neutron diffraction experiments as well as indentation measurements to study equation of state, constitutive properties, and hardness of nanocrystalline and bulk nickel. Our lattice volume–pressure data present a clear evidence of elastic softening in nanocrystalline Ni as compared with the bulk nickel. We show that the enhanced overall compressibility of nanocrystalline Ni is a consequence of the higher compressibility of the surface shell of Ni nanocrystals, which supports the results of molecular dynamics simulation and a generalized model of a nanocrystal with expanded surface layer. The analytical methods we developed based on the peak-profile of diffraction data allow us to identify “micro/local” yield due to high stress concentration at the grain-to-grain contacts and “macro/bulk” yield due to deviatoric stress over the entire sample. The graphic approach of our strain/stress analyses can also reveal the corresponding yield strength, grain crushing/growth, work hardening/softening, and thermal relaxation under highP–Tconditions, as well as the intrinsic residual/surface strains in the polycrystalline bulks. From micro-indentation measurements, we found that a low-temperature annealing (T < 0.4 Tm hardens nanocrystalline Ni, leading to an inverse Hall–Petch relationship. We explain this abnormal Hall–Petch effect in terms of impurity segregation to the grain boundaries of the nanocrystalline Ni.

  20. The three dimensional distribution of chromium and nickel alloy welding fumes.

    Science.gov (United States)

    Mori, T; Matsuda, A; Akashi, S; Ogata, M; Takeoka, K; Yoshinaka, M

    1991-08-01

    In the present study, the fumes generated from manual metal arc (MMA) and submerged metal arc (SMA) welding of low temperature service steel, and the chromium and nickel percentages in these fumes, were measured at various horizontal distances and vertical heights from the arc in order to obtain a three dimensional distribution. The MMA welding fume concentrations were significantly higher than the SMA welding fume concentrations. The highest fume concentration on the horizontal was shown in the fumes collected directly above the arc. The fume concentration vertically was highest at 50 cm height and reduced by half at 150 cm height. The fume concentration at 250 cm height was scarcely different from that at 150 cm height. The distribution of the chromium concentration vertically was analogous to the fume concentration, and a statistically significant difference in the chromium percentages was not found at the different heights. The nickel concentrations were not statistically significant within the welding processes, but the nickel percentages in the SMA welding fumes were statistically higher than in the MMA welding fumes. The highest nickel concentration on the horizontal was found in the fumes collected directly above the arc. The highest nickel concentration vertically showed in the fume samples collected at 50 cm height, but the greater the height the larger the nickel percentage in the fumes.

  1. A comparison of torque expression between stainless steel, titanium molybdenum alloy, and copper nickel titanium wires in metallic self-ligating brackets.

    Science.gov (United States)

    Archambault, Amy; Major, Thomas W; Carey, Jason P; Heo, Giseon; Badawi, Hisham; Major, Paul W

    2010-09-01

    The force moment providing rotation of the tooth around the x-axis (buccal-lingual) is referred to as torque expression in orthodontic literature. Many factors affect torque expression, including the wire material characteristics. This investigation aims to provide an experimental study into and comparison of the torque expression between wire types. With a worm-gear-driven torquing apparatus, wire was torqued while a bracket mounted on a six-axis load cell was engaged. Three 0.019 x 0.0195 inch wire (stainless steel, titanium molybdenum alloy [TMA], copper nickel titanium [CuNiTi]), and three 0.022 inch slot bracket combinations (Damon 3MX, In-Ovation-R, SPEED) were compared. At low twist angles (<12 degrees), the differences in torque expression between wires were not statistically significant. At twist angles over 24 degrees, stainless steel wire yielded 1.5 to 2 times the torque expression of TMA and 2.5 to 3 times that of nickel titanium (NiTi). At high angles of torsion (over 40 degrees) with a stiff wire material, loss of linear torque expression sometimes occurred. Stainless steel has the largest torque expression, followed by TMA and then NiTi.

  2. Nickel-based alloy/austenitic stainless steel dissimilar weld properties prediction on asymmetric distribution of laser energy

    Science.gov (United States)

    Zhou, Siyu; Ma, Guangyi; Chai, Dongsheng; Niu, Fangyong; Dong, Jinfei; Wu, Dongjiang; Zou, Helin

    2016-07-01

    A properties prediction method of Nickel-based alloy (C-276)/austenitic stainless steel (304) dissimilar weld was proposed and validated based on the asymmetric distribution of laser energy. Via the dilution level DC-276 (the ratio of the melted C-276 alloy), the relations between the weld properties and the energy offset ratio EC-276 (the ratio of the irradiated energy on the C-276 alloy) were built, and the effects of EC-276 on the microstructure, mechanical properties and corrosion resistance of dissimilar welds were analyzed. The element distribution Cweld and EC-276 accorded with the lever rule due to the strong convention of the molten pool. Based on the lever rule, it could be predicted that the microstructure mostly consists of γ phase in each weld, the δ-ferrite phase formation was inhibited and the intermetallic phase (P, μ) formation was promoted with the increase of EC-276. The ultimate tensile strength σb of the weld joint could be predicted by the monotonically increasing cubic polynomial model stemming from the strengthening of elements Mo and W. The corrosion potential U, corrosion current density I in the active region and EC-276 also met the cubic polynomial equations, and the corrosion resistance of the dissimilar weld was enhanced with the increasing EC-276, mainly because the element Mo could help form a steady passive film which will resist the Cl- ingress.

  3. Accelerated Degradation Test and Predictive Failure Analysis of B10 Copper-Nickel Alloy under Marine Environmental Conditions.

    Science.gov (United States)

    Sun, Bo; Ye, Tianyuan; Feng, Qiang; Yao, Jinghua; Wei, Mumeng

    2015-09-10

    This paper studies the corrosion behavior of B10 copper-nickel alloy in marine environment. Accelerated degradation test under marine environmental conditions was designed and performed based on the accelerated testing principle and the corrosion degradation mechanism. With the prolongation of marine corrosion time, the thickness of Cu₂O film increased gradually. Its corrosion product was Cu₂(OH)₃Cl, which increased in quantity over time. Cl(-) was the major factor responsible for the marine corrosion of copper and copper alloy. Through the nonlinear fitting of corrosion rate and corrosion quantity (corrosion weight loss), degradation data of different corrosion cycles, the quantitative effects of two major factors, i.e., dissolved oxygen (DO) and corrosion medium temperature, on corrosion behavior of copper alloy were analyzed. The corrosion failure prediction models under different ambient conditions were built. One-day corrosion weight loss under oxygenated stirring conditions was equivalent to 1.31-day weight loss under stationary conditions, and the corrosion rate under oxygenated conditions was 1.31 times higher than that under stationary conditions. In addition, corrosion medium temperature had a significant effect on the corrosion of B10 copper sheet.

  4. Accelerated Degradation Test and Predictive Failure Analysis of B10 Copper-Nickel Alloy under Marine Environmental Conditions

    Science.gov (United States)

    Sun, Bo; Ye, Tianyuan; Feng, Qiang; Yao, Jinghua; Wei, Mumeng

    2015-01-01

    This paper studies the corrosion behavior of B10 copper-nickel alloy in marine environment. Accelerated degradation test under marine environmental conditions was designed and performed based on the accelerated testing principle and the corrosion degradation mechanism. With the prolongation of marine corrosion time, the thickness of Cu2O film increased gradually. Its corrosion product was Cu2(OH)3Cl, which increased in quantity over time. Cl− was the major factor responsible for the marine corrosion of copper and copper alloy. Through the nonlinear fitting of corrosion rate and corrosion quantity (corrosion weight loss), degradation data of different corrosion cycles, the quantitative effects of two major factors, i.e., dissolved oxygen (DO) and corrosion medium temperature, on corrosion behavior of copper alloy were analyzed. The corrosion failure prediction models under different ambient conditions were built. One-day corrosion weight loss under oxygenated stirring conditions was equivalent to 1.31-day weight loss under stationary conditions, and the corrosion rate under oxygenated conditions was 1.31 times higher than that under stationary conditions. In addition, corrosion medium temperature had a significant effect on the corrosion of B10 copper sheet. PMID:28793549

  5. Accelerated Degradation Test and Predictive Failure Analysis of B10 Copper-Nickel Alloy under Marine Environmental Conditions

    Directory of Open Access Journals (Sweden)

    Bo Sun

    2015-09-01

    Full Text Available This paper studies the corrosion behavior of B10 copper-nickel alloy in marine environment. Accelerated degradation test under marine environmental conditions was designed and performed based on the accelerated testing principle and the corrosion degradation mechanism. With the prolongation of marine corrosion time, the thickness of Cu2O film increased gradually. Its corrosion product was Cu2(OH3Cl, which increased in quantity over time. Cl− was the major factor responsible for the marine corrosion of copper and copper alloy. Through the nonlinear fitting of corrosion rate and corrosion quantity (corrosion weight loss, degradation data of different corrosion cycles, the quantitative effects of two major factors, i.e., dissolved oxygen (DO and corrosion medium temperature, on corrosion behavior of copper alloy were analyzed. The corrosion failure prediction models under different ambient conditions were built. One-day corrosion weight loss under oxygenated stirring conditions was equivalent to 1.31-day weight loss under stationary conditions, and the corrosion rate under oxygenated conditions was 1.31 times higher than that under stationary conditions. In addition, corrosion medium temperature had a significant effect on the corrosion of B10 copper sheet.

  6. Effect of recasting on the elastic modulus of metal-ceramic systems from nickel-chromium and cobalt-chromium alloys

    Directory of Open Access Journals (Sweden)

    Mirković Nemanja

    2007-01-01

    Full Text Available Background/Aim. Elastic modulus of metal-ceramic systems determines their flexural strength and prevents damages on ceramics during mastication. Recycling of basic alloys is often a clinical practice, despite the possible effects on the quality of the future metal-ceramic dentures. This research was done to establish recasting effects of nickel-chromium and cobalt-chromium alloys on the elastic modulus of metalceramic systems in making fixed partial dentures. Methods. The research was performed as an experimental study. Six metal-ceramic samples of nickel-chromium alloy (Wiron 99 and cobalt-chromium alloy (Wirobond C were made. Alloy residues were recycled through twelve casting generations with the addition of 50% of new alloy on the occasion of every recasting. Three- point bending test was used to determine elastic modulus, recommended by the standard ISO 9693:1999. Fracture load for damaging ceramic layer was recorded on the universal testing machine (Zwick, type 1464, with the speed of 0,05 mm/min. Results. The results of this research revealed significant differences between elasticity modules of metal-ceramic samples in every examined recycle generation. Recasting had negative effect on the elastic modulus of the examined alloys. This research showed the slight linear reduction of elastic modulus up to the 6th generation of recycling. After the 6th recycling there was a sudden fall of elastic modulus. Conclusion. Recasting of nickelchromium and cobalt-chromium alloys is not recommended because of the reduced elastic modulus of these alloys. Instead of reusing previously recasted alloys, the alloy residues should be returned to the manufacturer. .

  7. Polymorphism in a high-entropy alloy

    Science.gov (United States)

    Zhang, Fei; Wu, Yuan; Lou, Hongbo; Zeng, Zhidan; Prakapenka, Vitali B.; Greenberg, Eran; Ren, Yang; Yan, Jinyuan; Okasinski, John S.; Liu, Xiongjun; Liu, Yong; Zeng, Qiaoshi; Lu, Zhaoping

    2017-06-01

    Polymorphism, which describes the occurrence of different lattice structures in a crystalline material, is a critical phenomenon in materials science and condensed matter physics. Recently, configuration disorder was compositionally engineered into single lattices, leading to the discovery of high-entropy alloys and high-entropy oxides. For these novel entropy-stabilized forms of crystalline matter with extremely high structural stability, is polymorphism still possible? Here by employing in situ high-pressure synchrotron radiation X-ray diffraction, we reveal a polymorphic transition from face-centred-cubic (fcc) structure to hexagonal-close-packing (hcp) structure in the prototype CoCrFeMnNi high-entropy alloy. The transition is irreversible, and our in situ high-temperature synchrotron radiation X-ray diffraction experiments at different pressures of the retained hcp high-entropy alloy reveal that the fcc phase is a stable polymorph at high temperatures, while the hcp structure is more thermodynamically favourable at lower temperatures. As pressure is increased, the critical temperature for the hcp-to-fcc transformation also rises.

  8. Effect of recasting of nickel-chromium alloy on its porosity

    Directory of Open Access Journals (Sweden)

    Jayant Palaskar

    2010-01-01

    Full Text Available Statement of Problem: As per the review of literature very few studies have been carried on recasting of dental casting alloy and in particlular its effect on occurrence of porosities. Purpose of Study: This study was designed to find out occurrence of porosities in new alloy and recasted alloy using a scanning electron microscope. Materials and Methods: Different percentage combinations of new and once casted alloy were used to produce twenty five samples. Castings obtained from new alloy were used as control group. All the samples were scanned under scanning electron mocroscope and photographs were taken from three specific sites for comparison. Results: There is no significant difference in occurrence of porosities in casting obtained by using new alloy and recasted alloy. Conclusion: With in the limitations of the study it is conducted that the prorosities will not be affected by recasting of neckel-chromium alloy. Clinical Implication: Porosities in dental casting alloy can alter physical and mechanical properties of the mental which inturn may lead to failure of crown and bridge, and also cast partial denture prosthesis.

  9. Boron Steel: An Alternative for Costlier Nickel and Molybdenum Alloyed Steel for Transmission Gears

    Directory of Open Access Journals (Sweden)

    A. Verma

    2010-06-01

    Full Text Available Case Carburized (CC low carbon steels containing Ni, Cr and Mo alloying elements are widely used for transmission gears in automobile, as it possesses desired mechanical properties. In order to cut cost and save scarce materials like Ni and Mo for strategic applications, steel alloyed with Boron has been developed, which gives properties comparable to Ni-Cr-Mo alloyed steel. In the process of steel development, care was taken to ensure precipitation of boron which results in precipitation hardening. The characterization of the developed boron steel had exhibited properties comparable to Ni-Cr-Mo alloyed steel and superior to conventional boron steel.

  10. Carbon coated nickel nanoparticles produced in high-frequency arc plasma at ambient pressure

    Science.gov (United States)

    Vnukova, Natalia; Dudnik, Alexander; Komogortsev, Sergey; Velikanov, Dmitry; Nemtsev, Ivan; Volochaev, Michael; Osipova, Irina; Churilov, Grigory

    2017-10-01

    The nickel particles with the mean size about 10-20 nm coated with carbon were extracted by the treatment of the carbon condensate with nitric and hydrochloric acids. The initial carbon condensate containing nickel nanoparticles with a graphite conversion was synthesized in the high-frequency carbon-helium arc plasma at ambient pressure with the nickel nanoparticles as a catalyst. The nickel content in the nanoparticles was 84.6 wt%. Magnetic properties of the nanoparticles are characterized by the high hysteresis and thermal stability. The sample of compacted nanoparticles is characterized by electrical resistance much higher than it in of compacted initial condensate.

  11. Effect of preconditioning cobalt and nickel based dental alloys with Bacillus sp. extract on their surface physicochemical properties and theoretical prediction of Candida albicans adhesion.

    Science.gov (United States)

    Balouiri, Mounyr; Bouhdid, Samira; Sadiki, Moulay; Ouedrhiri, Wessal; Barkai, Hassan; El Farricha, Omar; Ibnsouda, Saad Koraichi; Harki, El Houssaine

    2017-02-01

    Biofilm formation on dental biomaterials is implicated in various oral health problems. Thus the challenge is to prevent the formation of this consortium of microorganisms using a safe approach such as antimicrobial and anti-adhesive natural products. Indeed, in the present study, the effects of an antifungal extract of Bacillus sp., isolated from plant rhizosphere, on the surface physicochemical properties of cobalt and nickel based dental alloys were studied using the contact angle measurements. Furthermore, in order to predict the adhesion of Candida albicans to the treated and untreated dental alloys, the total free energy of adhesion was calculated based on the extended Derjaguin-Landau-Verwey-Overbeek approach. Results showed hydrophobic and weak electron-donor and electron-acceptor characteristics of both untreated dental alloys. After treatment with the antifungal extract, the surface free energy of both dental alloys was influenced significantly, mostly for cobalt based alloy. In fact, treated cobalt based alloy became hydrophilic and predominantly electron donating. Those effects were time-dependent. Consequently, the total free energy of adhesion of C. albicans to this alloy became unfavorable after treatment with the investigated microbial extract. A linear relationship between the electron-donor property and the total free energy of adhesion has been found for both dental alloys. Also, a linear relationship has been found between this latter and the hydrophobicity for the cobalt based alloy. However, the exposure of nickel based alloy to the antifungal extract failed to produce the same effect. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Electrochemical deposition and characterization of zinc–nickel alloys deposited by direct and reverse current

    Directory of Open Access Journals (Sweden)

    JELENA B. BAJAT

    2005-12-01

    Full Text Available Zn–Ni alloys electrochemically deposited on steel under various deposition conditions were investigated. The alloys were deposited on a rotating disc electrode and on a steel panel from chloride solutions by direct and reverse current. The influence of reverse plating variables (cathodic and anodic current densities and their time duration on the composition, phase structure and corrosion properties were investigated. The chemical content and phase composition affect the anticorrosive properties of Zn–Ni alloys during exposure to a corrosive agent (3 % NaCl solution. It was shown that the Zn–Ni alloy electrodeposited by reverse current with a full period T = 1 s and r = 0.2 exhibits the best corrosion properties of all the investigated alloys deposited by reverse current.

  13. Aluminium–copper–nickel thin film compositional spread: Nickel influence on fundamental alloy properties and chemical stability of copper

    Energy Technology Data Exchange (ETDEWEB)

    Hafner, Martina; Burgstaller, Wolfgang; Mardare, Andrei Ionut; Hassel, Achim Walter

    2015-04-01

    An Al–Cu–Ni thin film compositional spread was deposited by thermal evaporation and investigated in order to study the Ni influence on the overall properties. The chemical composition was detected by energy dispersive X-ray spectroscopy and showed a compositional spread of approximately 20 at.% Ni. Decreasing the Ni content in the Al–Cu–Ni thin films resulted in an increased grain size and characteristic surface microstructure evolution. Scanning Kelvin probe measurements were performed to investigate the surface potential variation along the compositional gradient, and a distinct surface potential drop was observed between Al–Cu–7 at.% Ni and Al–Cu–13 at.% Ni. The results of the X-ray photoelectron spectroscopy surface analysis and Auger electron spectroscopy as well as the electrochemical investigations by cyclic voltammetry evidenced mainly the presence of Al{sub 2}O{sub 3} but also CuO and Cu{sub 2}O together with metallic Cu were clearly identified along the compositional gradient. Chemical dissolution experiments have shown that Ni is enhancing the chemical stability of Cu, excepting inside the compositional region between 7 and 13 at.% Ni. - Highlights: • Properties of Al–Cu–Ni thin film combinatorial library (5–25 at.% Ni) were mapped. • A surface potential drop was found between AlCu–7 at.% Ni and AlCu–13 at.% Ni. • CuO, Cu{sub 2}O and Cu were found along the Al–Cu–Ni library by cyclic voltammetry. • Downstream analytics probed the corrosion behaviour of Al–Cu–Ni alloys. • Ni enhanced Cu chemical stability excepting the compositional range 7–13 at.% Ni.

  14. Reversible contraceptive effect of the oviduct plug with nickel-titanium shape memory alloy and silicone rubber in rabbits.

    Science.gov (United States)

    Wang, Lei-Guang; Qiu, Yi; Fan, Yun-Jing; Li, Xin-Ying; Han, Xiang-Jun

    2011-04-01

    The aim of this study was to observe the contraceptive effectiveness and reversibility of the oviduct plug with nickel-titanium (Ni-Ti) shape memory alloy and silicone rubber in rabbits. The oviduct plugs with Ni-Ti shape memory alloy and silicone rubber were made as contraceptive devices. The frame of the oviduct plug is made of silicone rubber and Ni-Ti shape memory alloy wire. The central part of the frame resembles a circular cylinder and the amphi-terminal of the frame is like a spigot which is formed with three mounting rings. Thirty-five New Zealand adult female rabbits were randomly divided into three groups. Thirty rabbits in Group 1 were used to test the contraceptive effect of the oviduct plug. Ten rabbits in Group 2 were used to assess the reproductive reversibility of the rabbits; 3 months after the operation, the oviduct plugs were removed from the junction of the uterus and tubes by incision of the abdomen. Another five rabbits (Group 3) served as the control group. In 30 female rabbits (Group 1), the plugs were inserted into the oviducts via a 0.5-cm incision of the uterus by using an inserter that contained the plug, then the female rabbits copulated with male rabbits once a week after the operation for 1 month. The plugs were then taken out from 10 rabbits (Group 2) 3 months after the operation. Out of 30 cases (Group 1), only one rabbit from Group 1 was pregnant 2 months after the insertion of the plugs due to improper insertion. However, five rabbits in the control group were all pregnant. All 10 rabbits from Group 2 were pregnant 1 month after the plug was removed. The oviduct plug with Ni-Ti shape memory alloy and silicone rubber is a new, effective and reversible contraceptive tool. Copyright © 2011 Elsevier Inc. All rights reserved.

  15. Determination of in vitro lung solubility and intake-to-dose conversion factor for tritiated lanthanum nickel aluminum alloy.

    Science.gov (United States)

    Farfán, Eduardo B; Labone, Thomas R; Staack, Gregory C; Cheng, Yung-Sung; Zhou, Yue; Varallo, Thomas P

    2012-09-01

    A sample of tritiated lanthanum nickel aluminum alloy (LaNi4.25Al0.75 or LANA.75) similar to that used at the Savannah River Site Tritium Facilities was analyzed to estimate the particle size distribution of this metal tritide powder and the rate at which this material dissolves in the human respiratory tract after it is inhaled. This information is used to calculate the committed effective dose received by a worker after inhaling the material. These doses, which were calculated using the same methodology given in the U.S. Department of Energy Tritium Handbook, are presented as inhalation intake-to-dose conversion factors (DCF). The DCF for this metal tritide was determined to be 9.4 × 10 Sv Bq, which is less than the DCF for tritiated water. Therefore, the radiation worker bioassay programs designed for tritiated water are adequate to monitor for intakes of this material.

  16. THE EFFECT OF THE CONDITIONS OF SHOT PEENING THE INCONEL 718 NICKEL ALLOY ON THE GEOMETRICAL STRUCTURE OF THE SURFACE

    Directory of Open Access Journals (Sweden)

    Kazimierz Zaleski

    2017-06-01

    Full Text Available The article presents the research results of roughness and topography of the surface of Inconel 718 nickel alloy after shot peening. Evaluation of stereometric properties of the surface layer of the examined material was performed based on the amplitude, height and Abbott-Firestone curve parametres. The shot peening was carried out on the impulse shot peening stand. The impact energy Ej, distance between the traces xs and the ball diameter dk were changed in the range: Ej = 60 ÷ 240 mJ, xs = 0,15 ÷ 0,5 mm, dk = 3,95 ÷ 12,45 mm. The T8000 RC 120-140 device of the Hommel-Etamic company, along with the software, was used for measuring the surface roughness and for determining the material bearing curve. As a result of the machin-ing, the surface roughness was reduced and the selected functional parameters were improved.

  17. Influences of Holes Arrangement on Creep Characteristic of Nickel-Base Single Crystal Alloy Blade Cooling Holes

    Directory of Open Access Journals (Sweden)

    Lei Li

    2013-01-01

    Full Text Available Film cooling technology is developed to enhance the temperature resistant of nickel-base single crystal alloy blade. The shape, dimension, and arrangement of cooling holes impact the blade strength and life grievously. In this paper, the influences of holes arrangement on creep characteristic of cooling holes in the plate sample are investigated. The constitutive model for creep considering both cavitation and degradation damage is developed to predict the creep behavior of cooling holes. Results show that there are stress interferences among cooling holes. The distance and radius of the cooling holes impact the creep behavior of cooling holes seriously. Decreasing horizontal distance of the holes results in creep time reducing. On the contrary, increasing the vertical distance of the holes makes the creep time reduced.

  18. DETERMINATION OF IN-VITRO LUNG SOLUBILITY AND INTAKE-TO-DOSE CONVERSION FACTOR FOR TRITIATED LANTHANUM NICKEL ALUMINUM ALLOY

    Energy Technology Data Exchange (ETDEWEB)

    Farfan, E.; Labone, T.; Staack, G.; Cheng, Y.; Zhou, Y.; Varallo, T.

    2011-11-11

    A sample of tritiated lanthanum nickel aluminum alloy (LaNi4.25Al0.75 or LANA.75) similar to that used at the Savannah River Site Tritium Facilities was analyzed to estimate the particle size distribution of this metal tritide powder and the rate, at which this material dissolves in the human respiratory tract after it is inhaled. This information is used to calculate the committed effective dose received by a worker after inhaling the material. These doses, which were calculated using the same methodology given in the DOE Tritium Handbook, are presented as inhalation intake-to-dose conversion factors (DCF). The DCF for this metal tritide is less than the DCF for tritiated water and radiation worker bioassay programs designed for tritiated water are adequate to monitor for intakes of this material.

  19. Effect of Laser Power on Metallurgical, Mechanical and Tribological Characteristics of Hardfaced Surfaces of Nickel-Based Alloy

    Science.gov (United States)

    Gnanasekaran, S.; Padmanaban, G.; Balasubramanian, V.

    2017-10-01

    In this present work, nickel based alloy was deposited on 316 LN austenitic stainless steel (ASS) by a laser hardfacing technique to investigate the influence of laser power on macrostructure, microstructure, microhardness, dilution and wear characteristics. The laser power varied from 1.1 to 1.9 kW. The phase constitution, microstructure and microhardness were examined by optical microscope, scanning electron microscopy, energy dispersion spectroscopy and Vickers microhardness tester. The wear characteristics of the hardfaced surfaces and substrate were evaluated at room temperature (RT) under dry sliding wear condition (pin-on-disc). The outcome demonstrates that as the laser power increases, dilution increases and hardness of the deposit decreases. This is because excess heat melts more volume of substrate material and increases the dilution; subsequently it decreases the hardness of the deposit. The microstructure of the deposit is characterized by Ni-rich carbide, boride and silicide.

  20. Dynamic Process Analysis In Cutting Zone During Machining Of Nickel Alloys

    Science.gov (United States)

    Czán, Andrej; Šajgalík, Michal; Martikáň, Anton; Mrázik, Jozef

    2015-12-01

    To generally improve effectivity of parts production and metal cutting process, there are used process models of super alloys together with finite element modeling simulations. Advanced measurement methods of the process could improve and verify the accuracy of these models. These methods cause many error sources when using empiric or exact methods such as infrared radiation thermography to measure the temperature distribution of the tool, workpiece, and chip during metal cutting. Measuring of metal machining is challenging due to factors such as the high magnification required, high surface speeds and deformations, micro-blackbody effects, changing emissivity and deformations present at metal cutting. As part of an ongoing effort to improve our understanding of uncertainties associated with these measurement methods, multimeasurement sets of experiments were performed. First set of measurements observed connection between surface temperature and the internal temperature of the cutting tool. This was accomplished by measuring the temperature using a thermal camera in cutting zone. Second set performed high-speed scan of dynamic processes such as formation of elastic and plastic deformation. During this operation was applied high-speed scannning system using macro conversion lens for monitoring of micro-structural changes in deformation areas. Next necessary applied set is recording of dynamic processes by implementation of piezoelectric measurement device for monitoring of cutting forces. The outputs from multimeasuring system are the basis for verification of theoretical knowledge from this field and elimination of uncertainties, which arise by using computer simulation systems.

  1. Pacific Northwest National Laboratory Investigation of the Stress Corrosion Cracking in Nickel-Base Alloys, Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Bruemmer, Stephen M.; Toloczko, Mychailo B.; Olszta, Matthew J.

    2012-03-01

    The objective of this program is to evaluate the primary water stress corrosion cracking (PWSCC) susceptibility of high chromium alloy 690 and its weld metals, establish quantitative measurements of crack-growth rates and determine relationships among cracking susceptibility, environmental conditions and metallurgical characteristics. Stress-corrosion, crack-growth rates have been determined for 12 alloy 690 specimens, 11 alloy 152/52/52M weld metal specimens, 4 alloy 52M/182 overlay specimens and 2 alloy 52M/82 inlay specimens in simulated PWR primary water environments. The alloy 690 test materials included three different heats of extruded control-rod-drive mechanism (CRDM) tubing with variations in the initial material condition and degree of cold work for one heat. Two cold-rolled (CR) alloy 690 plate heats were also obtained and evaluated enabling comparisons to the CR CRDM materials. Weld metal, overlay and inlay specimens were machined from industry mock ups to provide plant-representative materials for testing. Specimens have been tested for one alloy 152 weld, two alloy 52 welds and three alloy 52M welds. The overlay and inlay specimens were prepared to propagate stress-corrosion cracks from the alloy 182 or 82 material into the more resistant alloy 52M. In all cases, crack extension was monitored in situ by direct current potential drop (DCPD) with length resolution of about +1 µm making it possible to measure extremely low growth rates approaching 5x10-10 mm/s. Most SCC tests were performed at 325-360°C with hydrogen concentrations from 11-29 cc/kg; however, environmental conditions were modified during a few experiments to evaluate the influence of temperature, water chemistry or electrochemical potential on propagation rates. In addition, low-temperature (~50°C) cracking behavior was examined for selected alloy 690 and weld metal specimens. Extensive characterizations have been performed on material microstructures and stress-corrosion cracks by

  2. Pulsed Electrodeposited Nickel – Cerium for Hydrogen Production Studies

    OpenAIRE

    Sivaranjani, T; Revathy, T A; Dhanapal, K; Narayanan, V; A. Stephen

    2017-01-01

    International audience; The approach of alloying different elements results in new alloy phase with exclusive properties that could be a potential candidate in various applications. In the present work an attempt has been made to electrodeposit Nickel-Cerium (NiCe) alloy. Nickel is an intriguing metal with much availability in earth's crust. The catalytic power of Nickel based alloys towards hydrogen evolution reaction has been already reported for Nickel-Metal alloys, NiO/Ni and Nickel-Rare ...

  3. Metallurgical characterization of new palladium-containing cobalt chromium and nickel chromium alloys

    Science.gov (United States)

    Puri, Raghav

    Recently introduced to the market has been an entirely new subclass of casting alloy composition whereby palladium (˜25 wt%) is added to traditional base metal alloys such as CoCr and NiCr. Objectives. The purpose of this study was to evaluate the microstructure and Vickers hardness of two new CoPdCr and one new NiPdCr alloy and compare them to traditional CoCr and NiCr alloys. Methods. The casting alloys investigated were: CoPdCr-A (Noble Crown NF, The Argen Corporation), CoPdCr-I (Callisto CP+, Ivoclar Vivadent), NiPdCr (Noble Crown, Argen), CoCr (Argeloy N.P. Special, Argen), and NiCr (Argeloy N.P. Star, Argen). As-cast cylindrical alloy specimens were mounted in epoxy resin and prepared with standard metallographic procedures, i.e. grinding with successive grades of SiC paper and polishing with alumina suspensions. The alloys were examined with an optical microscope, SEM/EPMA, and XRD to gain insight into their microstructure, composition, and crystal structure. Vickers hardness (VHN) was measured and statistically analyzed by one way ANOVA and Tukey's HSD test (alpha=0.05). Results. Optical microscopy showed a dendritic microstructure for all alloys. The Pd-containing alloys appear to possess a more complex microstructure. SEM/EPMA showed Cr to be rather uniformly distributed in the matrix with palladium tending to be segregated apart from Mo and Ni or Co. Areas of different composition may explain the poor electrochemical results noted in previous studies. XRD suggested the main phase in the Ni-containing solutions was a face centered cubic Ni solid solution, whereas the CoCr exhibited a hexagonal crystal structure that was altered to face centered cubic when Pd was included in the composition. For Vickers hardness, the Co-containing alloys possessed a greater hardness than the Ni-containing alloys. However, the incorporation of Pd in CoCr and NiCr had only a slight effect on microhardness. Conclusion. Overall, the inclusion of palladium increases the

  4. Laser Brazing of High Temperature Braze Alloy

    Science.gov (United States)

    Gao, Y. P.; Seaman, R. F.; McQuillan, T. J.; Martiens, R. F.

    2000-01-01

    The Space Shuttle Main Engine (SSME) consists of 1080 conical tubes, which are furnace brazed themselves, manifolds, and surrounding structural jacket making almost four miles of braze joints. Subsequent furnace braze cycles are performed due to localized braze voids between the coolant tubes. SSME nozzle experiences extremely high heat flux (180 mW/sq m) during hot fire. Braze voids between coolant tubes may result in hot combustion gas escape causing jacket bulges. The nozzle can be disqualified for flight or result in mission failure if the braze voids exceed the limits. Localized braze processes were considered to eliminate braze voids, however, damage to the parent materials often prohibited use of such process. Being the only manned flight reusable rocket engine, it has stringent requirement on the braze process. Poor braze quality or damage to the parent materials limits the nozzle service life. The objective of this study was to develop a laser brazing process to provide quality, localized braze joints without adverse affect on the parent materials. Gold (Au-Cu-Ni-Pd-Mn) based high temperature braze alloys were used in both powder and wire form. Thin section iron base superalloy A286 tube was used as substrate materials. Different Laser Systems including CO2 (10.6 micrometers, 1kW), ND:YAG (1.06 micrometers, 4kW). and direct diode laser (808nm. 150W) were investigated for brazing process. The laser process variables including wavelength. laser power, travel speed and angle of inclination were optimized according to bead geometry and braze alloy wetting at minimum heat input level, The properties of laser brazing were compared to that of furnace brazing. Microhardness profiles were used for braze joint property comparison between laser and furnace brazing. The cooling rate of laser brazing was compared to furnace brazing based on secondary dendritic arm spacing, Both optical and Scanning Electron Microscope (SEM) were used to evaluate the microstructures of

  5. Polynitroaniline as brightener for zinc–nickel alloy plating from non ...

    Indian Academy of Sciences (India)

    ... presence of addition agent. Corrosion resistance test revealed good protection of base metal by zinc–nickel coating obtained from the developed electrolyte. SEM photomicrograph shows fine-grained deposit in the presence of addition agent. The consumption of brightener in the lab-scale was 0.01 gL-1 for 1000 amp-h.

  6. Alloy development for high burnup cladding (PWR)

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, R. [Kraftwerk Union AG, Mulheim (Germany); Jeong, Y.H.; Baek, K.H.; Kim, S.J.; Choi, B.K.; Kim, J.M. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1999-04-01

    An overview on current alloy development for high burnup PWR fuel cladding is given. It is mainly based on literature data. First, the reasons for an increase of the current mean discharge burnup from 35 MWd / kg(U) to 70 MWd / kg(U) are outlined. From the material data, it is shown that a batch average burnup of 60-70 MWd / kg(U), as aimed by many fuel vendors, can not be achieved with stand (=ASTM-) Zry-4 cladding tubes without violating accepted design criteria. Specifically criteria which limit maximum oxide scale thickness and maximum hydrogen content, and to a less degree, maximum creep and growth rate, can not be achieved. The development potential of standard Zry-4 is shown. Even when taking advantage of this potential, it is shown that an 'improved' Zry-4 is reaching its limits when it achieves the target burnup. The behavior of some Zr alloys outside the ASTM range is shown, and the advantages and disadvantages of the 3 alloy groups (ZrSn+transition metals, ZrNb, ZrSnNb+transition metals) which are currently considered to have the development potential for high burnup cladding materials are depicted. Finally, conclusions are drawn. (author). 14 refs., 11 tabs., 82 figs.

  7. DEVELOPMENT OF HIGH-TEMPERATURE TITANIUM ALLOY VT9,

    Science.gov (United States)

    The paper describes work, done in 1957-58, in the course of the development of the high-temperature (HT) Ti alloy currently termed BT9(VT9). The...target requirements for the new alloy specified the development of a Ti alloy for forging billets and stamping blanks which at 500 degrees centigrade

  8. FORMATION OF THIN COBALT AND NICKEL-COBALT ALLOY FILMS ON A GLASS SURFACE,

    Science.gov (United States)

    Cobalt and Ni-Co alloys were deposited at 100-500 A films on glass plates from citrate or ammoniacal solns. by hypophosphite redn. of dil. solns. of their metal chlorides. The method is discussed in detail.

  9. Mechanical properties of metal-ceramic systems from nickel-chromium and cobalt-chromium alloys

    National Research Council Canada - National Science Library

    Mirković, Nemanja

    2007-01-01

    .... The aim of this study was to evaluate metal-ceramic bond strenght and elastic modulus of cobalt-chromium alloys in making porcelain-fused-to-metal restorations, regarding the application of the most...

  10. Mechanical properties of metal-ceramic systems from nickel-chromium and cobalt-chromium alloys

    National Research Council Canada - National Science Library

    Mirkovic, Nemanja

    2007-01-01

    .... The aim of this study was to evaluate metal-ceramic bond strength and elastic modulus of cobalt-chromium alloys in making porcelainfused- to-metal restorations, regarding the application of the most...

  11. Excessively High Vapor Pressure of Al-based Amorphous Alloys

    OpenAIRE

    Jeong, Jae; Lee, Sung; Jeon, Je-Beom; Kim, Suk

    2015-01-01

    Aluminum-based amorphous alloys exhibited an abnormally high vapor pressure at their approximate glass transition temperatures. The vapor pressure was confirmed by the formation of Al nanocrystallites from condensation, which was attributed to weight loss of the amorphous alloys. The amount of weight loss varied with the amorphous alloy compositions and was inversely proportional to their glass-forming ability. The vapor pressure of the amorphous alloys around 573 K was close to the va...

  12. Characterization of Magnetron Sputtered Copper-Nickel Thin Film and Alloys

    Science.gov (United States)

    2016-09-01

    Deposition Sputter coating is the process of creating a vapor via physical means and depositing the vapor to form a thin film on a substrate...films 2.5 Composition Analysis of the Alloyed Films EDX spectroscopy is an analytical technique used for the elemental analysis or chemical...1000 °C in a low- pressure chemical vapor deposition (LPCVD) reactor with a gas mixture of 40%H2/60%Ar at 15 Torr pressure to form the final alloys

  13. Interrogation of the microstructure and residual stress of a nickel-base alloy subjected to surface severe plastic deformation

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, A.L. [Departamento de Ingenieria Mecanica, Energetica y de los Materiales, Universidad de Extremadura, 06071 Badajoz (Spain); Tian, J.W. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN (United States); Villegas, J.C. [Intel Corporation, Chandler, AZ (United States); Shaw, L.L. [Department of Chemical, Materials and Biomolecular Engineering, University of Connecticut, Storrs, CT (United States)], E-mail: Leon.Shaw@Uconn.Edu; Liaw, P.K. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN (United States)

    2008-02-15

    A low stacking-fault energy nickel-base, single-phase, face-centered-cubic (fcc) alloy has been subjected to surface severe plastic deformation (S{sup 2}PD) to introduce nano-grains and grain size gradients to the surface region of the alloy. The simultaneous microstructural and stress state changes induced by S{sup 2}PD have been investigated via the X-ray diffraction (XRD) analysis that includes evaluation of annealing and deformation twins, deformation faults, in-plane lattice parameters and elastic strains of the crystal lattice, macroscopic residual in-plane stresses, crystallite sizes, internal strains, dislocation densities, and crystallographic texture as a function of the depth measured from the processed surface. Microstructural changes have also been characterized using optical and electron microscopy in order to corroborate the findings from the XRD analysis. The results from the XRD analysis are in excellent agreement with those derived from the microscopy analysis. This is the first systematic and comprehensive study using XRD to quantify depth-profile changes in a wide range of microstructural features and stress states in a fcc material resulting from the S{sup 2}PD process.

  14. Distribution of nickel between copper-nickel and alumina saturated iron silicate slags

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, R.G.; Acholonu, C.C.

    1984-03-01

    The solubility of nickel in slag is determined in this article by equilibrating copper-nickel alloys with alumina-saturated iron silicate slags in an alumina crucible at 1573 K. The results showed that nickel dissolves in slag both as nickel oxide and as nickel metal. The presence of alumina is shown to increase the solubility of nickel in slags.

  15. Dwell Notch Low Cycle Fatigue Behavior of a Powder Metallurgy Nickel Disk Alloy

    Science.gov (United States)

    Telesman, J.; Gabb, T. P.; Yamada, Y.; Ghosn, L. J.; Jayaraman, N.

    2012-01-01

    A study was conducted to determine the processes which govern dwell notch low cycle fatigue (NLCF) behavior of a powder metallurgy (P/M) ME3 disk superalloy. The emphasis was placed on the environmentally driven mechanisms which may embrittle the highly stressed notch surface regions and reduce NLCF life. In conjunction with the environmentally driven notch surface degradation processes, the visco-plastic driven mechanisms which can significantly change the notch root stresses were also considered. Dwell notch low cycle fatigue testing was performed in air and vacuum on a ME3 P/M disk alloy specimens heat treated using either a fast or a slow cooling rate from the solutioning treatment. It was shown that dwells at the minimum stress typically produced a greater life debit than the dwells applied at the maximum stress, especially for the slow cooled heat treatment. Two different environmentally driven failure mechanisms were identified as the root cause of early crack initiation in the min dwell tests. Both of these failure mechanisms produced mostly a transgranular crack initiation failure mode and yet still resulted in low NLCF fatigue lives. The lack of stress relaxation during the min dwell tests produced higher notch root stresses which caused early crack initiation and premature failure when combined with the environmentally driven surface degradation mechanisms. The importance of environmental degradation mechanisms was further highlighted by vacuum dwell NLCF tests which resulted in considerably longer NLCF lives, especially for the min dwell tests.

  16. A probabilistic-based approach to monitoring tool wear state and assessing its effect on workpiece quality in nickel-based alloys

    Science.gov (United States)

    Akhavan Niaki, Farbod

    The objective of this research is first to investigate the applicability and advantage of statistical state estimation methods for predicting tool wear in machining nickel-based superalloys over deterministic methods, and second to study the effects of cutting tool wear on the quality of the part. Nickel-based superalloys are among those classes of materials that are known as hard-to-machine alloys. These materials exhibit a unique combination of maintaining their strength at high temperature and have high resistance to corrosion and creep. These unique characteristics make them an ideal candidate for harsh environments like combustion chambers of gas turbines. However, the same characteristics that make nickel-based alloys suitable for aggressive conditions introduce difficulties when machining them. High strength and low thermal conductivity accelerate the cutting tool wear and increase the possibility of the in-process tool breakage. A blunt tool nominally deteriorates the surface integrity and damages quality of the machined part by inducing high tensile residual stresses, generating micro-cracks, altering the microstructure or leaving a poor roughness profile behind. As a consequence in this case, the expensive superalloy would have to be scrapped. The current dominant solution for industry is to sacrifice the productivity rate by replacing the tool in the early stages of its life or to choose conservative cutting conditions in order to lower the wear rate and preserve workpiece quality. Thus, monitoring the state of the cutting tool and estimating its effects on part quality is a critical task for increasing productivity and profitability in machining superalloys. This work aims to first introduce a probabilistic-based framework for estimating tool wear in milling and turning of superalloys and second to study the detrimental effects of functional state of the cutting tool in terms of wear and wear rate on part quality. In the milling operation, the

  17. A comparative study of the cytotoxicity and corrosion resistance of nickel-titanium and titanium-niobium shape memory alloys.

    Science.gov (United States)

    McMahon, Rebecca E; Ma, Ji; Verkhoturov, Stanislav V; Munoz-Pinto, Dany; Karaman, Ibrahim; Rubitschek, Felix; Maier, Hans J; Hahn, Mariah S

    2012-07-01

    Nickel-titanium (NiTi) shape memory alloys (SMAs) are commonly used in a range of biomedical applications. However, concerns exist regarding their use in certain biomedical scenarios due to the known toxicity of Ni and conflicting reports of NiTi corrosion resistance, particularly under dynamic loading. Titanium-niobium (TiNb) SMAs have recently been proposed as an alternative to NiTi SMAs due to the biocompatibility of both constituents, the ability of both Ti and Nb to form protective surface oxides, and their superior workability. However, several properties critical to the use of TiNb SMAs in biomedical applications have not been systematically explored in comparison with NiTi SMAs. These properties include cytocompatibility, corrosion resistance, and alterations in alloy surface composition in response to prolonged exposure to physiological solutions. Therefore, the goal of the present work was to comparatively investigate these aspects of NiTi (49.2 at.% Ti) and TiNb (26 at.% Nb) SMAs. The results from the current studies indicate that TiNb SMAs are less cytotoxic than NiTi SMAs, at least under static culture conditions. This increased TiNb cytocompatibility was correlated with reduced ion release as well as with increased corrosion resistance according to potentio-dynamic tests. Measurements of the surface composition of samples exposed to cell culture medium further supported the reduced ion release observed from TiNb relative to NiTi SMAs. Alloy composition depth profiles also suggested the formation of calcium phosphate deposits within the surface oxide layers of medium-exposed NiTi but not of TiNb. Collectively, the present results indicate that TiNb SMAs may be promising alternatives to NiTi for certain biomedical applications. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  18. The implantation of a Nickel-Titanium shape memory alloy ameliorates vertebral body compression fractures: a cadaveric study.

    Science.gov (United States)

    Chen, Bo; Zheng, Yue-Huang; Zheng, Tao; Sun, Chang-Hui; Lu, Jiong; Cao, Peng; Zhou, Jian-Hua

    2015-01-01

    To evaluate the effect of a Nickel-Titanium (Ni-Ti) shape memory alloy in the treatment of vertebral body compression fractures. The experimental thoracic-lumbar fracture units were made with adult human fresh-frozen vertebral specimens. A total of 30 fresh-frozen vertebral units were randomly assigned to 3 experimental groups: control group, percutaneous kyphoplasty group (PKP group), and percutaneous Ni-Ti shape memory alloys implant group (Ni-Ti implant group). Vertebral height and ultimate compression load of the vertebral body before and after procedures were measured to determine the restoration of vertebral heights and compressive strength, respectively. The Ni-Ti implant group achieved a vertebrae endplate reduction effect comparable to the PKP group. The vertebral height of the PKP group was restored from 2.01±0.21 cm to 2.27±0.18 cm after procedure, whereas that of the Ni-Ti implant group was restored from 2.00±0.18 cm to 2.31±0.17 cm. The ultimate loads of the vertebrae body of the PKP and the Ni-Ti implant groups were 2880.75±126.17 N and 2888.00±144.69 N, respectively, both of which were statistically significantly higher than that of the control group (2017.17±163.71 N). There was no significant difference in ultimate compression load of vertebrae body between the Ni-Ti implant and PKP groups. The implantation of Ni-Ti shape memory alloys of vertebral body induced effective endplate reduction, restored vertebral height, and provided immediate biomechanical spinal stability.

  19. Analysis of zirconium and nickel based alloys and zirconium oxides by relative and internal monostandard neutron activation analysis methods

    Energy Technology Data Exchange (ETDEWEB)

    Shinde, Amol D.; Acharya, Raghunath; Reddy, Annareddy V. R. [Bhabha Atomic Research Centre, Mumbai (India)

    2017-04-15

    The chemical characterization of metallic alloys and oxides is conventionally carried out by wet chemical analytical methods and/or instrumental methods. Instrumental neutron activation analysis (INAA) is capable of analyzing samples nondestructively. As a part of a chemical quality control exercise, Zircaloys 2 and 4, nimonic alloy, and zirconium oxide samples were analyzed by two INAA methods. The samples of alloys and oxides were also analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES) and direct current Arc OES methods, respectively, for quality assurance purposes. The samples are important in various fields including nuclear technology. Samples were neutron irradiated using nuclear reactors, and the radioactive assay was carried out using high-resolution gamma-ray spectrometry. Major to trace mass fractions were determined using both relative and internal monostandard (IM) NAA methods as well as OES methods. In the case of alloys, compositional analyses as well as concentrations of some trace elements were determined, whereas in the case of zirconium oxides, six trace elements were determined. For method validation, British Chemical Standard (BCS)-certified reference material 310/1 (a nimonic alloy) was analyzed using both relative INAA and IM-NAA methods. The results showed that IM-NAA and relative INAA methods can be used for nondestructive chemical quality control of alloys and oxide samples.

  20. Effects of alloy composition on cyclic flame hot-corrosion attack of cast nickel-base superalloys at 900 deg C

    Science.gov (United States)

    Deadmore, D. L.

    1984-01-01

    The effects of Cr, Al, Ti, Mo, Ta, Nb, and W content on the hot corrosion of nickel base alloys were investigated. The alloys were tested in a Mach 0.3 flame with 0.5 ppmw sodium at a temperature of 900 C. One nondestructive and three destructive tests were conducted. The best corrosion resistance was achieved when the Cr content was 12 wt %. However, some lower-Cr-content alloys ( 10 wt%) exhibited reasonable resistance provided that the Al content alloys ( 10 wt %) exhibited reasonable resistance provided that the Al content was 2.5 wt % and the Ti content was Aa wt %. The effect of W, Ta, Mo, and Nb contents on the hot-corrosion resistance varied depending on the Al and Ti contents. Several commercial alloy compositions were also tested and the corrosion attack was measured. Predicted attack was calculated for these alloys from derived regression equations and was in reasonable agreement with that experimentally measured. The regression equations were derived from measurements made on alloys in a one-quarter replicate of a 2(7) statistical design alloy composition experiment. These regression equations represent a simple linear model and are only a very preliminary analysis of the data needed to provide insights into the experimental method.

  1. High Copper Amalgam Alloys in Dentistry

    Directory of Open Access Journals (Sweden)

    Gaurav Solanki

    2012-07-01

    Full Text Available Amalgam Restoration is an example of the material giving its name to the process. Amalgam fillings are made up of mercury, powdered silver and tin. They are mixed and packed into cavities in teeth where it hardens slowly and replaces the missing tooth substance. The high copper have become material of choice as compared to low copper alloys nowadays because of their improved mechanical properties, corrosion resistance, better marginal integrity and improved performance in clinical trial. The high copper amalgam was used as a restorative material. The application of high copper amalgam was found to be much more useful than low copper amalgam. High copper had much more strength, corrosion resistance, durability and resistance to tarnish as compared to low copper amalgams. No marked expansion or condensation was noted in the amalgam restoration after its setting after 24 hrs. By using the high copper alloy, the chances of creep were also minimized in the restored tooth. No discomfort or any kind of odd sensation in the tooth was noted after few days of amalgam restoration in the tooth.

  2. Transient Liquid Phase Bonding of Nickel-Base Single Crystal Alloy with a Novel Ni-Cr-Co-Mo-W-Ta-Re-B Amorphous Interlayer

    Science.gov (United States)

    Guo, Wei; Wang, Haiyan; Jia, Qiang; Peng, Peng; Zhu, Ying

    2017-07-01

    A novel Ni-Cr-Co-W-Mo-Ta-Re-B alloy consisting of plate γ and M23B6 phases was prepared as interlayer for the transient liquid phase (TLP) bonding of Rene' N5 nickel-base single crystal superalloy. The molten Ni-Cr-Co-W-Mo-Ta-Re-B alloy exhibited an excellent wettability on the nickel-base superalloy. The TLP bonding experiment has been carried out in vacuum furnace at 1,240 ° for 12 h and followed by post-weld heat treatment (PWHT) at 1,305 ° for 4 h. PWHT eliminated the intermetallic compounds and promoted the formation of γ´ precipitates in the bonding region. A more uniform microhardness profile of TLP joint was found after PWHT. The shear strength of the joint after PWHT significantly increased to 533.4 MPa compared with the value of 437.2 MPa without PWHT.

  3. XPS and electrochemical impedance spectroscopy studies on effects of the porcelain firing process on surface and corrosion properties of two nickel-chromium dental alloys.

    Science.gov (United States)

    Qiu, Jing; Tang, Chun-bo; Zhu, Zhi-jun; Zhou, Guo-xing; Wang, Jie; Yang, Yi; Wang, Guo-ping

    2013-11-01

    The aim of this study was to evaluate the effects of a simulated porcelain firing process on the surface, corrosion behavior and cell culture response of two nickel-chromium (Ni-Cr) dental alloys. A Be-free alloy and a Be-containing alloy were tested. Before porcelain firing, as-cast specimens were examined for surface composition using X-ray photoelectron spectroscopy and metallurgical phases using X-ray diffraction. Corrosion behaviors were evaluated using electrochemical impedance spectroscopy. 3T3 fibroblasts were cultured and exposed indirectly to specimens. MTT assays were counted after 3 and 6 days. The cell culture mediums exposed to specimens were analyzed for metal ion release. After porcelain firing, similar specimens were examined for the same properties. In both as-cast and fired conditions, the Be-free Ni-Cr alloy showed significantly more resistance to corrosion than the Be-containing Ni-Cr alloy, which exhibited BeNi phase. After porcelain firing, the corrosion resistance of the Be-free Ni-Cr alloy decreased statistically, corresponding with evident decreases of Cr and Ni oxides on the alloy surface. Also, the alloy's MTT assay decreased significantly corresponding with an obvious increase of Ni-ion release after the firing. For the Be-containing Ni-Cr alloy, the firing process led to increases of surface oxides and metallic Be, while its corrosion resistance and cell culture response were not significantly changed after porcelain firing. The results suggested that the corrosion resistance and biocompatibility of the Be-free Ni-Cr alloy decreased after porcelain firing, whereas the firing process had little effect on the same properties of the Be-containing Ni-Cr alloy.

  4. The recasting effects on the high gold dental alloy properties

    Directory of Open Access Journals (Sweden)

    Maksimović V.M.

    2015-01-01

    Full Text Available Noble dental alloys are often reused in dental practice by recasting. The aim of this study was to determine if repeated casting of high gold dental alloys has a detrimental effect on alloy microstructure, type of porosity, structure and microhardness. Results showed that recasting procedure had a strong effect on the change of alloy porosity type. It was also found that alloy microhardness increased with the increase of the number of recasting cycles. At the same time the grain growth and changes of the solid solution phases in the microstructure were observed. [Projekat Ministarstva nauke Republike Srbije, br. III 45012

  5. STRUCTURE, PHASE COMPOSITION AND PROPERTIES OF GAS-THERMAL COVERINGS OF MECHANICALLY ALLOYED THERMOREACTING COMPOSITE POWDERS OF NICKEL-ALUMINIUM SYSTEM

    Directory of Open Access Journals (Sweden)

    F. G. Lovshenko

    2015-01-01

    Full Text Available The presented results show that coverings from mechanically alloyed thermoreacting powders of system «nickel–aluminum» are nonequilibrium multiphase systems which basis represents solid solution of aluminum in nickel. It has the microcrystalline type of structure which is characterized by an advanced surface of borders of the grains and subgrains stabilized by nanodimensional inclusions of oxides and alyuminid. These coverings surpass by 1,2–1,6 times analogs in durability, hardness and wear resistance.

  6. How NO affects nickel and cobalt nitrates at low temperatures to arrive at highly dispersed silica-supported nickel and cobalt catalysts

    NARCIS (Netherlands)

    Wolters, M.|info:eu-repo/dai/nl/304829560; Munnik, P.|info:eu-repo/dai/nl/328228524; Bitter, J.H.|info:eu-repo/dai/nl/160581435; de Jongh, P.E.|info:eu-repo/dai/nl/186125372; de Jong, K.P.|info:eu-repo/dai/nl/06885580X

    2011-01-01

    Impregnation of porous silica supports with cobalt and nickel nitrate precursor solutions is a convenient method to prepare supported nickel and cobalt (oxide) catalysts. However, the metal (oxide) dispersion obtained is highly dependent on the gas atmosphere during thermal treatment to convert the

  7. PRODUCTION OF NICKEL CONCENTRATE OF WORKED-OUT METAL-CONTAINING CATALYSTS WITH LOW NICKEL CONTENT

    Directory of Open Access Journals (Sweden)

    O. S. Komarov

    2011-01-01

    Full Text Available The carried out series of experiments confirmed the technical reasonability of enrichment of exhaust nickel catalysts with the purpose of their further usage as nickel concentrates for alloying of casting alloys.

  8. Polynitroaniline as brightener for zinc–nickel alloy plating from non ...

    Indian Academy of Sciences (India)

    Electroplated zinc coatings are considered as one of the many ways of corrosion protection of steel. Recently, interest in. Zn–Ni alloy coating has increased owing to its better mecha- nical and corrosion properties compared with pure zinc coatings (Shears 1989; Angelopoulos 2001; Brooks and. Erb 2001; Muller et al 2002).

  9. Reusable High Aspect Ratio 3-D Nickel Shadow Mask.

    Science.gov (United States)

    Shandhi, M M H; Leber, M; Hogan, A; Warren, D J; Bhandari, R; Negi, S

    2017-04-01

    Shadow Mask technology has been used over the years for resistless patterning and to pattern on unconventional surfaces, fragile substrate and biomaterial. In this work, we are presenting a novel method to fabricate high aspect ratio (15:1) three-dimensional (3D) Nickel (Ni) shadow mask with vertical pattern length and width of 1.2 mm and 40 μm respectively. The Ni shadow mask is 1.5 mm tall and 100 μm wide at the base. The aspect ratio of the shadow mask is 15. Ni shadow mask is mechanically robust and hence easy to handle. It is also reusable and used to pattern the sidewalls of unconventional and complex 3D geometries such as microneedles or neural electrodes (such as the Utah array). The standard Utah array has 100 active sites at the tip of the shaft. Using the proposed high aspect ratio Ni shadow mask, the Utah array can accommodate 300 active sites, 200 of which will be along and around the shaft. The robust Ni shadow mask is fabricated using laser patterning and electroplating techniques. The use of Ni 3D shadow mask will lower the fabrication cost, complexity and time for patterning out-of-plane structures.

  10. Precipitation in solid solution and structural transformations in single crystals of high rhenium ruthenium-containing nickel superalloys at high-temperature creep

    Energy Technology Data Exchange (ETDEWEB)

    Alekseev, A.A.; Petrushin, N.V.; Zaitsev, D.V.; Treninkov, I.A.; Filonova, E.V. [All-Russian Scientific Research Institute of Aviation Materials (VIAM), Moscow (Russian Federation)

    2010-07-01

    The phase composition and structure of single crystals of two superalloys (alloy 1 and alloy 2) were investigated in this work. For alloy 1 (Re - 9 wt%) the kinetics of precipitation in solid solution at heat treatment (HT) was investigated. TEM and X-Ray examinations have revealed that during HT rhombic phase (R-phase) precipitation (Immm class (BCR)) occurs. The TTT diagram is plotted, it contains the time-temperature area of the existence of R-phase particles. The element content of R-phase is identified (at. %): Re- 51.5; Co- 23.5; Cr- 14.8; Mo- 4.2; W- 3.3; Ta- 2.7. For alloy 2 (Re - 6.5 wt %, Ru - 4 wt %) structural transformations at high-temperature creep are investigated. By dark-field TEM methods it is established, that in alloy 2 the additional phase with a rhombic lattice is formed during creep. Particles of this phase precipitate in {gamma}-phase and their quantity increases during high-temperature creep. It is revealed that during creep 3-D dislocation network is formed in {gamma}-phase. At the third stage of creep the process of inversion structure formation is observed in the alloy, i.e. {gamma}'-phase becomes a matrix. Thus during modeling creep the volume fraction of {gamma}'-phase in the samples increases from 30% (at creep duration of 200 hrs) up to 55% (at 500 hrs). The processes of structure formation in Re and Ru-containing nickel superalloys are strongly affected by decomposition of solid solution during high-temperature creep that includes precipitation of additional TCP-phases. (orig.)

  11. Microstructure and magnetic properties of mechanically alloyed FeSiBAlNi (Nb) high entropy alloys

    Science.gov (United States)

    Wang, Jian; Zheng, Zhou; Xu, Jing; Wang, Yan

    2014-04-01

    In this paper, the effects of milling duration and composition on the microstructure and magnetic properties of equi-atomic FeSiBAlNi and FeSiBAlNiNb high entropy alloys during mechanical alloying have been investigated using X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, transmission electron microscopy and alternating gradient magnetometry. The amorphous high entropy alloys have been successfully fabricated using the mechanical alloying method. The results show that the Nb addition prolongs the milling time for the formation of the fully FeSiBAlNi amorphous phase and decreases the glass forming ability. However, FeSiBAlNiNb amorphous high entropy alloy has the higher thermal stability and heat resisting properties. Moreover, the as-milled FeSiBAlNi(Nb) powders are soft-magnetic materials indicated by their low coercivity. The saturation magnetization of the as-milled FeSiBAlNi(Nb) powders decreases with prolonging of the milling time and shows the lowest value when the amorphous high entropy alloys are formed. It suggests that the as-milled products with solid solution phases show the better soft-magnetic properties than those with fully amorphous phases. The Nb addition does not improve the soft-magnetic properties of the FeSiBAlNi high entropy alloys. Rather, both amorphous high entropy alloys have similar soft-magnetic properties after a long milling time.

  12. High-strength, low-alloy steels.

    Science.gov (United States)

    Rashid, M S

    1980-05-23

    High-strength, low-alloy (HSLA) steels have nearly the same composition as plain carbon steels. However, they are up to twice as strong and their greater load-bearing capacity allows engineering use in lighter sections. Their high strength is derived from a combination of grain refinement; precipitation strengthening due to minor additions of vanadium, niobium, or titanium; and modifications of manufacturing processes, such as controlled rolling and controlled cooling of otherwise essentially plain carbon steel. HSLA steels are less formable than lower strength steels, but dualphase steels, which evolved from HSLA steels, have ferrite-martensite microstructures and better formability than HSLA steels of similar strength. This improved formability has substantially increased the utilization potential of high-strength steels in the manufacture of complex components. This article reviews the development of HSLA and dual-phase steels and discusses the effects of variations in microstructure and chemistry on their mechanical properties.

  13. An evaluation of the shape of some popular nickel titanium alloy preformed arch wires.

    Science.gov (United States)

    Braun, S; Hnat, W P; Leschinsky, R; Legan, H L

    1999-07-01

    The mathematical Beta function is shown to be an accurate planar representation of the natural human arch form defined by the spatial coordinates of the labial and buccal dental/bracket interfacing surfaces in the maxillary and mandibular arches. Graphic planar representations of the corresponding bracket base spatial coordinates of 33 popular preformed nickel titanium arch wires and bracket assemblies were superimposed on each of the relevant maxillary and mandibular natural forms. The arch forms of the preformed nickel titanium arch wires and bracket assemblies did not emulate the natural human arch form. The average mandibular natural human arch form first molar/canine width ratio is 2.38/1; the same preformed arch wire/bracket ratio is 1.87/1. These ratios for the maxillary arch are 1.92/1 and 1.54/1, respectively. The average canine width exceeded the natural canine width by 5.95 mm in the mandibular arch and 8.23 mm in the maxillary arch. The corresponding mandibular first molar and maxillary first molar widths exceeded the natural human first molar arch width by 0.84 mm and 2.68 mm, respectively. These findings have implications with respect to posttreatment stability and facial esthetics. "Round tripping" teeth resulting from subsequent change to stainless steel arch wires to restore a more natural human arch form and size may result in deleterious tissue effects.

  14. Processing of Ni30Pt20Ti50 High-Temperature Shape-Memory Alloy Into Thin Rod Demonstrated

    Science.gov (United States)

    Noebe, Ronald D.; Draper, Susan L.; Biles, Tiffany A.; Leonhardt, Todd

    2005-01-01

    High-temperature shape-memory alloys (HTSMAs) based on nickel-titanium (NiTi) with significant ternary additions of palladium (Pd), platinum (Pt), gold (Au), or hafnium (Hf) have been identified as potential high-temperature actuator materials for use up to 500 C. These materials provide an enabling technology for the development of "smart structures" used to control the noise, emissions, or efficiency of gas turbine engines. The demand for these high-temperature versions of conventional shape-memory alloys also has been growing in the automotive, process control, and energy industries. However these materials, including the NiPtTi alloys being developed at the NASA Glenn Research Center, will never find widespread acceptance unless they can be readily processed into useable forms.

  15. Composition tunable cobalt–nickel and cobalt–iron alloy nanoparticles below 10 nm synthesized using acetonated cobalt carbonyl

    NARCIS (Netherlands)

    van Schooneveld, Matti M.|info:eu-repo/dai/nl/315032863; Campos-Cuerva, Carlos; Pet, Jeroen; Meeldijk, Johannes D.|info:eu-repo/dai/nl/323921647; van Rijssel, Jos; Meijerink, Andries; Erne, Ben H.|info:eu-repo/dai/nl/141937378; de Groot, Frank M. F.|info:eu-repo/dai/nl/08747610X

    A general organometallic route has been developed to synthesize CoxNi1-x and CoxFe1-x alloy nanoparticles with a fully tunable composition and a size of 4–10 nm with high yield. In contrast to previously reported synthesis methods using dicobalt octacarbonyl (Co2(CO)8), here the cobalt–cobalt bond

  16. Microstructure of Cast Ni-Cr-Al-C Alloy

    Directory of Open Access Journals (Sweden)

    Cios G.

    2015-04-01

    Full Text Available Nickel based alloys, especially nickel based superalloys have gained the advantage over other alloys in the field of high temperature applications, and thus become irreplaceable at high temperature creep and aggressive corrosion environments, such as jet engines and steam turbines. However, the wear resistance of these alloys is insufficient at high temperatures. This work describes a microstructure of a new cast alloy. The microstructure consists of γ matrix strengthened by γ’ fine precipitates (dendrites improving the high temperature strength and of Chromium Cr7C3 primary carbides (in interdendritic eutectics which are designed to improve wear resistance as well as the high temperature strength.

  17. Effects of alloying on aging and hardening processes of steel with 20% nickel

    Science.gov (United States)

    Bogachev, I. N.; Zvigintsev, N. V.; Maslakova, T. M.

    1981-01-01

    Measurements of hardness, thermal emf, and electrical resistance were used to study the effects of Co, Mo, Ti and Al contents on aging and hardening processes in Fe 20%Ni steel. It is shown that the effects of these alloying elements differ substantially. Anomalies which arise in the temperature dependence of physical properties due to the presence of cobalt and molybdenum are reduced by the inclusion of titanium and aluminum (and vice versa).

  18. Diamond-like nanocomposite coatings for LIGA-fabricated nickel alloy parts.

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, Somuri V.; Scharf, Thomas W.

    2005-03-01

    A commercial plasma enhanced chemical vapor deposition (PECVD) technique with planetary substrate rotation was used to apply a thin (200-400 nm thick) conformal diamond-like carbon (DLC) coating (known as a diamond-like nanocomposite (DLN)) on LIGA fabricated Ni-Mn alloy parts. The PECVD technique is known to overcome the drawbacks associated with the line-of-sight nature of physical vapor deposition (PVD) and substrate heating inherent with traditional chemical vapor deposition (CVD). The purpose of the present study is to characterize the coverage, adhesion, and tribological (friction and wear) behavior of DLN coatings applied to planar and sidewall surfaces of small featured LIGA Ni-Mn fabricated parts, e.g. 280 {micro}m thick sidewalls. Friction and wear tests were performed in dry nitrogen, dry air, and air with 50% RH at Hertzian contact pressures ranging from 0.3 to 0.6 GPa. The friction coefficient of bare Ni-Mn alloy was determined to be 0.9. In contrast, low friction coefficients ({approx}0.02 in dry nitrogen and {approx}0.2 in 50% RH air) and minimal amount of wear were exhibited for the DLN coated LIGA Ni-Mn alloy parts and test coupons. This behavior was due to the ability of the coating to transfer to the rubbing counterface providing low interfacial shear at the sliding contact; resultantly, coating one surface was adequate for low friction and wear. In addition, a 30 nm thick titanium bond layer was determined to be necessary for good adhesion of DLN coating to Ni-Mn alloy substrates. Raman spectroscopy and cross-sectional SEM with energy dispersive x-ray analysis revealed that the DLN coatings deposited by the PECVD with planetary substrate rotation covered both the planar and sidewall surfaces of LIGA fabricated parts, as well as narrow holes of 300 {micro}m (0.012 inch) diameter.

  19. Fracture of nickel-titanium superelastic alloy in sodium hypochlorite solution

    Energy Technology Data Exchange (ETDEWEB)

    Yokoyama, Ken' ichi; Kaneko, Kazuyuki; Yabuta, Eiji; Asaoka, Kenzo; Sakai, Jun' ichi

    2004-03-25

    Fracture of the Ni-Ti superelastic alloy for endodontic instruments such as files was investigated with a sustained tensile-loading test in sodium hypochlorite (NaOCl) solution of various concentrations. It was found that the time to fracture was reduced when the applied stress exceeded the critical stress for martensite transformation. When the applied stress was higher than the critical stress, the 0.3 mm diameter wires of the Ni-Ti superelastic alloy sometimes fractured within 60 min. From the results of observations of the fracture surface using a scanning electron microscope, it was revealed that the fracture of the Ni-Ti superelastic alloy is significantly influenced by corrosion when the applied stress was higher than the critical stress for martensite transformation. The results of the present study suggest that one of the causes of the fracture of Ni-Ti files during clinical use is corrosion under the applied stress above the critical stress for martensite transformation in NaOCl solution.

  20. Corrosion of pre-oxidized nickel alloy X-750 in simulated BWR environment

    Science.gov (United States)

    Tuzi, Silvia; Lai, Haiping; Göransson, Kenneth; Thuvander, Mattias; Stiller, Krystyna

    2017-04-01

    Samples of pre-oxidized Alloy X-750 were exposed to a simulated boiling water reactor environment in an autoclave at a temperature of 286 °C and a pressure of 80 bar for four weeks. The effect of alloy iron content on corrosion was investigated by comparing samples with 5 and 8 wt% Fe, respectively. In addition, the effect of two different surface pre-treatments was investigated. The microstructure of the formed oxide scales was studied using mainly electron microscopy. The results showed positive effects of an increased Fe content and of removing the deformed surface layer by pickling. After four weeks of exposure the oxide scale consists of oxides formed in three different ways. The oxide formed during pre-oxidization at 700 °C, mainly consisting of chromia, is partly still present. There is also an outer oxide consisting of NiFe2O4 crystals, reaching a maximum size of 3 μm, which has formed by precipitation of dissolved metal ions. Finally, there is an inner nanocrystalline and porous oxide, with a metallic content reflecting the alloy composition, which has formed by corrosion.

  1. In situ Raman spectroscopic analysis of surface oxide films on Ni-base alloy/low alloy steel dissimilar metal weld interfaces in high-temperature water

    Science.gov (United States)

    Kim, Jongjin; Choi, Kyung Joon; Bahn, Chi Bum; Kim, Ji Hyun

    2014-06-01

    In situ Raman spectroscopy has been applied to analyze the surface oxide films formed on dissimilar metal weld (DMW) interfaces of nickel-base alloy/low alloy steel under hydrogenated high-temperature water condition. For the analysis of the oxide films under high temperature/pressure aqueous conditions, an in situ Raman spectroscopy system was developed by constructing a hydrothermal cell where the entire optics including the excitation laser and the Raman light collection system were located at the nearest position to the specimen by means of immersion optics. In situ Raman spectra of the DMW interfaces were collected in hydrogenated water condition at different temperatures up to 300 °C. The measured in situ Raman spectra showed peaks of Cr2O3, NiCr2O4 and Fe3O4 at the DMW interface. It is considered that differences in the oxide chemistry originated from the chemical element distribution inside of the DMW interface region.

  2. High-temperature ordered intermetallic alloys V

    Energy Technology Data Exchange (ETDEWEB)

    Baker, I. (ed.) (Dartmouth Coll., Hanover, NH (United States). Thayer School of Engineering); Darolia, R. (ed.) (GE Aircraft Engines, Cincinnati, OH (United States)); Whittenberger, J.D. (ed.) (NASA, Cleveland, OH (United States). Lewis Research Center); Yoo, M.H. (ed.) (Oak Ridge National Lab., TN (United States))

    1993-01-01

    These proceedings represent the written record of the High-Temperature Ordered Intermetallic Alloys 5 Symposium which was held in conjunction with the 1992 Fall Materials Research Society meeting in Boston, Massachusetts. This symposium, which was the fifth in the series originated by C.C Koch, C.T. Liu and N.S. Stoloff in 1984, was very successful with 86 oral presentations over four days, and approximately 140 posters given during two lively evening sessions. Such a response, in view of the increasing number of conferences being held on intermetallics each year, reveals the continued high regard for this series of symposia. Individual papers have been processed separately for inclusion in the appropriate data bases.

  3. Effect of Specific Energy Input on Microstructure and Mechanical Properties of Nickel-Base Intermetallic Alloy Deposited by Laser Cladding

    Science.gov (United States)

    Awasthi, Reena; Kumar, Santosh; Chandra, Kamlesh; Vishwanadh, B.; Kishore, R.; Viswanadham, C. S.; Srivastava, D.; Dey, G. K.

    2012-12-01

    This article describes the microstructural features and mechanical properties of nickel-base intermetallic alloy laser-clad layers on stainless steel-316 L substrate, with specific attention on the effect of laser-specific energy input (defined as the energy required per unit of the clad mass, kJ/g) on the microstructure and properties of the clad layer, keeping the other laser-cladding parameters same. Defect-free clad layers were observed, in which various solidified zones could be distinguished: planar crystallization near the substrate/clad interface, followed by cellular and dendritic morphology towards the surface of the clad layer. The clad layers were characterized by the presence of a hard molybdenum-rich hexagonal close-packed (hcp) intermetallic Laves phase dispersed in a relatively softer face-centered cubic (fcc) gamma solid solution or a fine lamellar eutectic phase mixture of an intermetallic Laves phase and gamma solid solution. The microstructure and properties of the clad layers showed a strong correlation with the laser-specific energy input. As the specific energy input increased, the dilution of the clad layer increased and the microstructure changed from a hypereutectic structure (with a compact dispersion of characteristic primary hard intermetallic Laves phase in eutectic phase mixture) to near eutectic or hypoeutectic structure (with reduced fraction of primary hard intermetallic Laves phase) with a corresponding decrease in the clad layer hardness.

  4. Material composition and nuclear data libraries' influence on nickel-chromium alloys activation evaluation: a comparison with decay heat experiments

    CERN Document Server

    Cepraga, D G

    2000-01-01

    The paper presents the activation analyses on Inconel-600 nickel-chromium alloy. Three activation data libraries, namely the EAF-4.1, the EAF-97 and the FENDL/A-2, and the FENDL/D-2 decay data library, have been used to perform the calculation with the European activation code ANITA-4/M. The neutron flux distribution into the material samples was provided by JAERI as results of 3D Monte-Carlo MCNP transport code experiment simulation. A comparison with integral decay heat measurement performed at the Fusion Neutronics Source (FNS), JAERI, Tokai, Japan, is used to validate the computational approach. The calculation results are given and discussed. The impact of the material composition, including impurities, on the decay heat of samples irradiated in fusion-like neutron spectra is assessed and discussed. The discrepancies calculations-experiments are within the experimental errors, that is between 6% and 10%, except for the short cooling times (less than 40 min after the end of irradiation). To improve calcul...

  5. Effect of Processing Parameters on the Protective Quality of Electroless Nickel-Phosphorus on Cast Aluminium Alloy

    Directory of Open Access Journals (Sweden)

    Olawale Olarewaju Ajibola

    2015-01-01

    Full Text Available The effects of temperature, pH, and time variations on the protective amount and quality of electroless nickel (EN deposition on cast aluminium alloy (CAA substrates were studied. The temperature, pH, and plating time were varied while the surface condition of the substrate was kept constant in acid or alkaline bath. Within solution pH of 5.0–5.5 range, the best quality is obtained in acid solution pH of 5.2. At lower pH (5.0–5.1, good adhesion characterised the EN deposition. Within the range of plating solution pH of 7.0 to 11.5, the highest quantity and quality of EN deposition are obtained on CAA substrate in solution pH of 10.5. It is characterised with few pores and discontinuous metallic EN film. The quantity of EN deposition is time dependent, whereas the adhesion and brightness are not time controlled. The best fit models were developed from the trends of result data obtained from the experiments. The surface morphologies and the chemical composition of the coating were studied using the Jeol JSM-7600F field emission scanning electron microscope.

  6. Properties of electrochromic nickel-vanadium oxide films sputter-deposited from nonmagnetic alloy target

    Science.gov (United States)

    Avendano, Esteban; Azens, Andris; Niklasson, Gunnar A.

    2001-11-01

    In this study we investigate the structure, composition, diffusion coefficient, and electrochromic properties of nickel-vanadium oxide films as a function of deposition conditions. Polycrystalline films have been deposited by DC magnetron sputtering from a nonmagnetic target of Ni0.93V0.07 in an atmosphere of O2/Ar and Ar/O2/H2, with the gas flow ratios varied systematically to cover the range from nearly-metallic to overoxidized films. The results contradict the usual view that films deposited in O2/Ar are dark brown in their as-deposited state. While such films can easily be deposited, the optimum electrochromic properties have been observed at O2/Ar ratios giving nearly transparent films. Addition of hydrogen to the sputtering atmosphere improved cycling stability of the films. The diffusion coefficient has been determined by the Galvanostatic Intermittent Titration Technique (GITT).

  7. High performance transparent conductor of graphene wrapped copper/nickel microgrids

    Science.gov (United States)

    Wu, Wei; Tassi, Nancy G.; Walls, Dennis J.; Zhang, Lei; Willner, Bruce

    2014-12-01

    A high performance, highly stable transparent conducting structure based on microscale copper/nickel grids wrapped with graphene is presented. Graphene is selectively deposited on the surfaces of the microgrids by atmospheric pressure chemical vapor deposition method. The optical transmittance of the copper/nickel microgrid sample is ˜80% over the visible and near-infrared spectra with a very small sheet resistance of ˜0.58 Ω/sq. After the high temperature deposition of graphene, the sample's transmittance increases to be ˜90% due to the line width reduction of the microgrids while the sheet resistance also increases to ˜5 Ω/sq. The graphene layer is deposited to keep the copper/nickel surfaces from being oxidized in the air. Both stability testing and composition spectra results confirm the long-term stability of the copper/nickel microgrids wrapped with graphene.

  8. KCl-induced high temperature corrosion of selected commercial alloys. Part I: chromia-formers

    DEFF Research Database (Denmark)

    Kiamehr, Saeed; Dahl, Kristian Vinter; Montgomery, Melanie

    2015-01-01

    Laboratory testing of selected chromia-forming alloys was performed to rank the materials and gain further knowledge on the mechanism of KCl-induced high temperature corrosion. The investigated alloys were stainless steels EN1.4021, EN1.4057, EN1.4521, TP347H (coarse-grained), TP347HFG (fine......-grained), Sanicro 28 and the nickel-based alloys 625, 263 and C276. Exposure was performed at 600 °C for 168 h in flowing N2(g)+5%O2(g)+15% H2O(g) (vol.%). Samples were covered with KCl powder prior to exposure. A salt-free exposure was also performed for comparison. Corrosion morphology and products were studied...... with scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffractometry (XRD). It was observed that in the salt-free exposure, stainless steels TP347H (coarse-grained) and EN1.4521 failed to form a thin protective oxide layer compared to the oxide formed on the other alloys...

  9. Additive Manufacturing of High-Entropy Alloys by Laser Processing

    NARCIS (Netherlands)

    Ocelik, V.; Janssen, Niels; Smith, Stefan; De Hosson, J. Th M.

    This contribution concentrates on the possibilities of additive manufacturing of high-entropy clad layers by laser processing. In particular, the effects of the laser surface processing parameters on the microstructure and hardness of high-entropy alloys (HEAs) were examined. AlCoCrFeNi alloys with

  10. Comparison of brazed joints made with BNi-1 and BNi-7 nickel-base brazing alloys

    Directory of Open Access Journals (Sweden)

    Zorc, Borut

    2000-04-01

    Full Text Available Kinetics of the processes are different with different types of brazing alloys. Precipitation processes in the parent metal close to the brazing gap are of great importance. They control the mechanical properties of the joint area when the brittle eutectic has disappeared from the gap. A comparative study of brazed joints on austenitic stainless alloys made with BNi-7 (Ni-P type and BNi-1 (Ni-Si-B type brazing alloys was made. Brazing alloys containing phosphorus behave in a different manner to those containing boron.

    Las aleaciones de níquel se producen mediante tres sistemas de aleación: Ni-P, Ni-Si y Ni-B. Durante las reacciones metalúrgicas con el metal de base, la eutéctica frágil en la separación soldada puede transformarse en la solución dúctil-sólida con todas aleaciones. La cinética del proceso varía según el tipo de aleación. Los procesos de precipitación en el metal de base cerca de la separación soldada son de mucha importancia, ya que controlan las propiedades mecánicas de la área de unión después de desaparecer la eutéctica frágil de la separación. Se ha hecho un análisis comparativo de uniones soldadas en aleaciones austeníticas inoxidables realizadas con aleaciones BNi-7 (tipo Ni-P y BNi-1 (tipo Ni-Si-B. Las aleaciones que contienen fósforo se comportan de una manera diferente, tanto con el cambio de la eutéctica a la solución sólida, como con los procesos de precipitación en el metal de base cerca de la unión soldada.

  11. Recent Progress in High Entropy Alloy Research

    Science.gov (United States)

    MacDonald, B. E.; Fu, Z.; Zheng, B.; Chen, W.; Lin, Y.; Chen, F.; Zhang, L.; Ivanisenko, J.; Zhou, Y.; Hahn, H.; Lavernia, E. J.

    2017-10-01

    Since their discovery in 2004, high-entropy alloys (HEAs) have generated significant interest from the scientific community. Based on a multi-principal element design approach, HEAs are engineered to possess a unique random solid solution (RSS) crystalline structure, in which each of the constituent elements has an equal probability of occupying a given lattice site. Published literature reports that certain HEAs exhibit exceptional chemical, physical, mechanical and functional properties that are attributed to the presence of a RSS phase. Not surprisingly, research on HEAs has begun to expand at an accelerated rate. The scientific and engineering topics being studied include: experimentally measuring various properties in HEA systems, understanding the effect of the RSS on these properties, and developing methods for predicting the formation of RSS phases. Accordingly, the goal of this brief review is to introduce the field of HEAs, discuss their core concepts, highlight exceptional properties, and discuss current design aspects.

  12. Standard practice for determining the susceptibility of stainless steels and related Nickel-Chromium-Iron Alloys to stress-corrosion cracking in polythionic acids

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This practice covers procedures for preparing and conducting the polythionic acid test at room temperature, 22 to 25°C (72 to 77°F), to determine the relative susceptibility of stainless steels or other related materials (nickel-chromiumiron alloys) to intergranular stress corrosion cracking. 1.2 This practice can be used to evaluate stainless steels or other materials in the “as received” condition or after being subjected to high-temperature service, 482 to 815°C (900 to 1500°F), for prolonged periods of time. 1.3 This practice can be applied to wrought products, castings, and weld metal of stainless steels or other related materials to be used in environments containing sulfur or sulfides. Other materials capable of being sensitized can also be tested in accordance with this test. 1.4 This practice may be used with a variety of stress corrosion test specimens, surface finishes, and methods of applying stress. 1.5 This standard does not purport to address all of the safety concerns, if any, ...

  13. Long-Term Corrosion Protection of a Cupro-Nickel Alloy Due to Graphene Coating

    Directory of Open Access Journals (Sweden)

    Abhishek Tiwari

    2017-11-01

    Full Text Available This study demonstrates the corrosion resistance of a Cu-Ni alloy coated with a multi-layer graphene. This is one of the first demonstrations of long-term corrosion resistance due to graphene coating, which is crucial since earlier studies have suggested graphene-coated copper to be considerably inferior to bare copper in terms of corrosion during long-term exposure to a corrosive environment. The inferior corrosion resistance of graphene-coated copper arises due to defects and poor surface coverage by graphene. Since it is prohibitively difficult to develop defect-free graphene on metals at a commercially feasible scale, this study investigated the hypothesis for an alternative approach, i.e., to develop multi-layer graphene with a reasonable assumption that the areas of defects/poor coverage of a layer will be masked by the subsequent over-layer(s. This study has validated this hypothesis. Electrochemical investigations have demonstrated multi-layer graphene to improve the corrosion resistance of a Cu-Ni alloy by an order of magnitude. However, the most striking finding of this study is that the improvement in corrosion resistance due to the multi-layer graphene coating sustained the entire duration of a long-term test (~350 h.

  14. Effect of environmental and stress intensity factors on IGA/SCC of nickel-base alloy

    Energy Technology Data Exchange (ETDEWEB)

    Hirano, H.; Kawamura, H. (Central Research Inst. of Electric Power Industry, Komae, Tokyo (Japan). Komae Research Lab.)

    1993-12-01

    Inconel alloy 600 has been used for PWR Steam Generator (SG) tubes due to its superior corrosion resistance and excellent thermal conductivity. However, it is reported that Intergranular Attack and Stress Corrosion Cracking (IGA/SCC) has occurred in the crevices between the tube and tube sheet or tube support plate. Therefore, it is important to clarify the IGA/SCC initiation and propagation behaviors and establish the countermeasure against IGA/SCC. This report describes the effect of environmental and stress intensity factors on the IGA/SCC initiation and propagation behaviors in the alloy 600 tube. The main results are as follows: (1) IGA/SCC test results showed that IGA/SCC crack did not propagate rapidly within the stress intensity factor range in which the crack tip of tube is loaded under PWR secondary condition. (2) SG model boiler test revealed that IGA/SCC propagation rate is slow, i.e., 10[sup -3] to 10[sup -2] [mu]m/hr. (author).

  15. Excessively High Vapor Pressure of Al-based Amorphous Alloys

    Directory of Open Access Journals (Sweden)

    Jae Im Jeong

    2015-10-01

    Full Text Available Aluminum-based amorphous alloys exhibited an abnormally high vapor pressure at their approximate glass transition temperatures. The vapor pressure was confirmed by the formation of Al nanocrystallites from condensation, which was attributed to weight loss of the amorphous alloys. The amount of weight loss varied with the amorphous alloy compositions and was inversely proportional to their glass-forming ability. The vapor pressure of the amorphous alloys around 573 K was close to the vapor pressure of crystalline Al near its melting temperature, 873 K. Our results strongly suggest the possibility of fabricating nanocrystallites or thin films by evaporation at low temperatures.

  16. Non-enzymatic glucose sensing on copper-nickel thin film alloy

    Science.gov (United States)

    Pötzelberger, Isabella; Mardare, Andrei Ionut; Hassel, Achim Walter

    2017-09-01

    A simple and cost efficient glucose sensor was constructed using 3D printing having as active material a copper-15 at.% nickel thin film thermally co-evaporated on copper plated circuit boards. The glucose detection in alkaline solution was studied in detail by cyclic voltammetric and chronoamperometric measurements. The sensor suitability for being used in both quantitative and qualitative glucose detection was demonstrated and calibration of its response to various amounts of glucose revealed two linear regimes with different sensitivities. Glucose levels between 0 and 10 mM are most efficiently quantified as indicated by an amperometric signal increase of 240 μA cm-2 for each 1 mM increase of glucose concentration. The potentiostatic stability of the sensor was evaluated and its complete insensitivity after 7 h was solely attributed to the irreversible transformation of glucose into gluconolactone. A sensor life time of 20 cycles was demonstrated during potentiodynamic cycling when the sensor response remains constant at its maximum level. The magnitude of possible glucose quantification errors were evaluated as interferences induced by additions of ascorbic and uric acids. A worst case scenario of 96 % accuracy of glucose levels quantification was demonstrated using 25 times higher concentrations of interfering substances as compared to the glucose level.

  17. High conductivity Be-Cu alloys for fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Lilley, E.A. [NGK Metals Corp., Reading, PA (United States); Adachi, Takao; Ishibashi, Yoshiki [NGK Insulators, Ltd., Aichi-ken (Japan)

    1995-09-01

    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.

  18. Determination of thermophysical and structural properties of nickel super-alloy

    Directory of Open Access Journals (Sweden)

    S. Zlá

    2015-10-01

    Full Text Available In this work the differential thermal analysis (DTA was selected for the study of 718Plus super-alloy. Particular attention was paid to determination of the phase transformation temperatures (liquidus, γ´ precipitation temperature, etc.. Almost at all temperatures of samples an undercooling was observed. Shifting of almost all temperatures was observed in the heating/cooling mode towards higher values with an increasing rate of heating, lower values with the increasing cooling rate. On the basis of DTA and structural analysis it may be stated that development of phase transformations will probably correspond to the following scheme: melting → γ phase; melting → γ + MC (NbC, TiC; melting + MC → γ + Laves + σ; γ → γ´ (γ´´.

  19. Comparison of experimental and theoretical thermal fatigue lives for five nickel-base alloys.

    Science.gov (United States)

    Spera, D. A.

    1972-01-01

    Alloys investigated were Nimonic 90, IN 100, coated IN 100, B 1900, coated B 1900, MAR M200, and MAR M200DS (directionally solidified). Maximum temperatures ranged from 770 to 1120 C. Specimen geometries included tapered disks, double-edged wedges, and cambered airfoils. The disks and wedges were heated and cooled in fluidized beds. The airfoil specimens were heated by a Mach 1 natural gas burner and rapid-air cooled, with and without spanwise loading. Life calculations included two distinct failure modes: conventional low-cycle fatigue and cyclic creep. The complete life calculation system included the calculation of transient temperature distributions, thermal strains, stresses, creep damage, fatigue damage, and finally cycles to first crack. Calculated lives were within a factor of two for 76 of the 86 data points analyzed.

  20. Comparison of experimental and theoretical thermal fatigue lives for five nickel base alloys

    Science.gov (United States)

    Spera, D. A.

    1972-01-01

    The alloys Nimonic 90, IN 100, coated IN 100, B 1900, coated B 1900, MAR M200, and MAR M200DS (directionally solidified) were studied. Maximum temperatures ranged from 770 C to 1120 C (1420 F to 2050 F). Specimen geometries included tapered disks, double-edged wedges, and cambered airfoils. The disks and wedges were heated and cooled in fluidized beds. The airfoil specimens were heated by a Mach 1 natural gas burner and rapid-air-cooled, with and without spanwise loading. Life calculations included two distinct failure modes: conventional low cycle fatigue and cyclic creep. Required material properties were limited to conventional thermal, tensile, and creep rupture data. The complete life calculation system included the calculation of transient temperature distributions, thermal strains, stresses, creep damage, fatigue damage, and cycles to first crack. Calculated lives were within a factor of two for 76 of the 86 data points analyzed. Cyclic creep accounted for 81% of all the calculated damage.

  1. Influence of the brazing parameters on microstructure and mechanical properties of brazed joints of Hastelloy B2 nickel base alloy; Influencia de los parametros de soldeo fuerte en la microestructura y propiedades mecanicas de la union de la aleacion base niquel Hastelloy B2

    Energy Technology Data Exchange (ETDEWEB)

    Sotelo, J. C.; Gonzalez, M.; Porto, E.

    2014-07-01

    A study of the high vacuum brazing process of solid solution strengthened Hastelloy B2 nickel alloy has been done. A first stage of research has focused on the selection of the most appropriate brazing filler metal to the base material and vacuum furnace brazing process. The influence of welding parameters on joint microstructure constituents, relating the microstructure of the joint to its mechanical properties, has been evaluated. Two gaps of 50 and 200 micrometers, and two dwell times at brazing temperature of 10 and 90 minutes were studied. The braze joint mainly consists of the nickel rich matrix, nickel silicide and ternary compounds. Finally, the results of this study have shown the high bond strength for small gaps and increased dwell times of 90 minutes. (Author)

  2. Fiber laser cladding of nickel-based alloy on cast iron

    Science.gov (United States)

    Arias-González, F.; del Val, J.; Comesaña, R.; Penide, J.; Lusquiños, F.; Quintero, F.; Riveiro, A.; Boutinguiza, M.; Pou, J.

    2016-06-01

    Gray cast iron is a ferrous alloy characterized by a carbon-rich phase in form of lamellar graphite in an iron matrix while ductile cast iron presents a carbon-rich phase in form of spheroidal graphite. Graphite presents a higher laser beam absorption than iron matrix and its morphology has also a strong influence on thermal conductivity of the material. The laser cladding process of cast iron is complicated by its heterogeneous microstructure which generates non-homogeneous thermal fields. In this research work, a comparison between different types of cast iron substrates (with different graphite morphology) has been carried out to analyze its impact on the process results. A fiber laser was used to generate a NiCrBSi coating over flat substrates of gray cast iron (EN-GJL-250) and nodular cast iron (EN-GJS-400-15). The relationship between processing parameters (laser irradiance and scanning speed) and geometry of a single laser track was examined. Moreover, microstructure and composition were studied by Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS) and X-Ray Diffraction (XRD). The hardness and elastic modulus were analyzed by means of micro- and nanoindentation. A hardfacing coating was generated by fiber laser cladding. Suitable processing parameters to generate the Ni-based alloy coating were determined. For the same processing parameters, gray cast iron samples present higher dilution than cast iron samples. The elastic modulus is similar for the coating and the substrate, while the Ni-based coating obtained presents a significantly superior hardness than cast iron.

  3. Fatigue in a heat treatable high silicon containing aluminium alloy

    Science.gov (United States)

    González, J. A.; Talamantes-Silva, J.; Valtierra, S.; Colás, Rafael

    2017-05-01

    The use of cast aluminium alloys in automobiles contributes to reductions in weight and fuel consumption without impairing the safety for the occupants or the performance of the car. Most of the alloys used are heat treatable hypoeutectic Al-Si alloys, which have the drawback of exhibiting low wear resistance. So industry relies in wear resistant alloys, such as grey iron, for the liners of the combustion chambers in engine blocks, which increase the weight of the engine. Therefore, it is of interest to cast high silicon containing alloys into engine components that are able to resist wear while maintaining the mechanical properties required by the components. This work presents the result of the work carried out in a high silicon containing heat treatable aluminium alloy as it is subjected to high cycle fatigue. The alloy was prepared and cast in ingots designed to promote one dimensional solidification gradient to obtain samples to study the high cycle fatigue. The material was machined into hour-glass specimens that were tested at room temperature in a servohydraulic machine under load control following the stair case method. The results show that the resistance to fatigue depends on the microstructure of the sample, as the fatigue cracks originate in pores close to the surface of the sample and propagate through the eutectic aggregate. The results from this work are compared with those from previously obtained with hypoeutectic alloys.

  4. Microstructure Evolution During Stainless Steel-Copper Vacuum Brazing with a Ag/Cu/Pd Filler Alloy: Effect of Nickel Plating

    Science.gov (United States)

    Choudhary, R. K.; Laik, A.; Mishra, P.

    2017-03-01

    Vacuum brazing of stainless steel and copper plates was done using a silver-based filler alloy. In one set of experiments, around 30-µm-thick nickel coatings were electrochemically applied on stainless steel plates before carrying out the brazing runs and its effect in making changes in the braze-zone microstructure was studied. For brazing temperature of 830 °C, scanning electron microscopy examination of the braze-zone revealed that relatively sound joints were obtained when brazing was done with nickel-coated stainless steel than with uncoated one. However, when brazing of nickel-coated stainless steel and copper plates was done at 860 °C, a wide crack appeared in the braze-zone adjacent to copper side. Energy-dispersive x-ray analysis and electron microprobe analysis confirmed that at higher temperature, the diffusion of Cu atoms from copper plate towards the braze-zone was faster than that of Ni atoms from nickel coating. Helium leak rate of the order 10-11 Pa m3/s was obtained for the crack-free joint, whereas this value was higher than 10-4 Pa m3/s for the joint having crack. The shear strength of the joint was found to decrease considerably due to the presence of crack.

  5. Corrosion behavior of Haynes {sup registered} 230 {sup registered} nickel-based super-alloys for integrated coal gasification combined cycle syngas plants. A plant exposure study

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sungkyu; Lee, Jieun; Kang, Suk-Hwan; Lee, Seung-Jong; Yun, Yongseung [Institute for Advanced Engineering (IAE), Gyeonggi-do (Korea, Republic of). Plant Engineering Center; Kim, Min Jung [Sungkyunkwan Univ, Gyeonggi-do (Korea, Republic of). Advanced Materials Technology Research Center

    2015-07-01

    The corrosion behavior of commercially available Haynes {sup registered} 230 {sup registered} nickel-based alloy samples was investigated by exposure to coal-gasifying integrated coal gasification combined cycle pilot plant facilities affiliated with the Institute for Advanced Engineering (2.005 MPa and 160-300 C). The morphological and microstructural analyses of the exposed samples were conducted using scanning electron microscopy and energy-dispersive X-ray spectroscopy analysis on the external surface of the recovered corrosion test samples to obtain information of the corrosion scale. These analyses based on the pre- and post-exposure corrosion test samples combined with thermodynamic Ellingham-Pourbaix stability diagrams provided preliminary insight into the mechanism of the observed corrosion behavior prevailing in the piping materials that connected the particulate removal unit and water scrubber of the integrated coal gasification combined cycle pilot plant. Uniform material wastage was observed after 46 hours of operation, and a preliminary corrosion mechanism was suggested: the observed material waste and corrosion behavior of the Haynes {sup registered} 230 {sup registered} nickel-based alloy samples cut off from the coal syngas integrated coal gasification combined cycle plant were explained by the formation of discontinuous (complex) oxide phases and subsequent chlorine-induced active oxidation under the predominantly reducing environment encountered. This contribution continues the already published studies of the Fe-Ni-Cr-Co alloy Haynes {sup registered} 556 {sup registered}.

  6. Study of the high-temperature corrosion of heat-resisting alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wada, K.

    1986-01-01

    An experimental study is reported of the corrosion resistance of the heat-resistant materials which play such an important role in the development of high-efficiency coal gasification combined-cycle power generation. Specifically, a study was made of the high-temperature and molten salt corrosion of nickel base alloys in coal combustion gas environments. The authors outline various types of high-temperature corrosion which occur: oxidation, sulfidation, decarburization and carburizing, nitridation, hot corrosion and halogenation. The mechanisms involved in molten salt corrosion are explained with reference to various models and currently available data. Finally, a study of electro-chemical measuring methods is reported. The authors conclude that future work on corrosion in coal gasification combined cycle power generation systems should concentrate on the following items: 1) elucidating the conditions under which molten salts form; 2) developing methods for predicting the quantity of molten salts which will form, and for assessing their contribution to corrosion; 3) evaluating the corrosion resistance of specific alloys to molten salts of given composition; 4) clarifying the effect of alloy surface temperature on corrosion resistance and local corrosion; and 5) developing techniques for predicting the amount of corrosion. 24 references, 28 figures, 7 tables.

  7. Biocompatibility of dental alloys

    Energy Technology Data Exchange (ETDEWEB)

    Braemer, W. [Heraeus Kulzer GmbH and Co. KG, Hanau (Germany)

    2001-10-01

    Modern dental alloys have been used for 50 years to produce prosthetic dental restorations. Generally, the crowns and frames of a prosthesis are prepared in dental alloys, and then veneered by feldspar ceramics or composites. In use, the alloys are exposed to the corrosive influence of saliva and bacteria. Metallic dental materials can be classified as precious and non-precious alloys. Precious alloys consist of gold, platinum, and small amounts of non-precious components such as copper, tin, or zinc. The non-precious alloys are based on either nickel or cobalt, alloyed with chrome, molybdenum, manganese, etc. Titanium is used as Grade 2 quality for dental purposes. As well as the dental casting alloys, high purity electroplated gold (99.8 wt.-%) is used in dental technology. This review discusses the corrosion behavior of metallic dental materials with saliva in ''in vitro'' tests and the influence of alloy components on bacteria (Lactobacillus casei and Streptococcus mutans). The test results show that alloys with high gold content, cobalt-based alloys, titanium, and electroplated gold are suitable for use as dental materials. (orig.)

  8. Cyclic fatigue resistance of XP-endo Shaper compared with different nickel-titanium alloy instruments.

    Science.gov (United States)

    Elnaghy, Amr; Elsaka, Shaymaa

    2017-10-13

    The aims of this study were to assess and compare the resistance to cyclic fatigue of XP-endo Shaper (XPS; FKG Dentaire, La Chaux-de-Fonds, Switzerland) instruments with TRUShape (TRS; Dentsply Tulsa Dental Specialties, Tulsa, OK, USA), HyFlex CM (HCM; Coltene, Cuyahoga Falls, OH, USA), Vortex Blue (VB; Dentsply Tulsa Dental Specialties), and iRace (iR; FKG Dentaire) nickel-titanium rotary instruments at body temperature. Size 30, 0.01 taper of XPS, size 30, 0.04 taper of HCM, VB, iR, and size 30, 0.06 taper of TRS instruments were immersed in saline at 37 ± 1 °C during cyclic fatigue testing. The instruments were tested with 60° angle of curvature and a 3-mm radius of curvature. The number of cycles to failure (NCF) was calculated and the length of the fractured segment was measured. Fractographic examination of the fractured surface was performed using a scanning electron microscope. The data were analyzed statistically using Kruskal-Wallis H test and Mann-Whitney U tests. Statistical significance was set at P < 0.05. XPS had a significantly greater NCF compared with the other instruments (P < 0.001). The topographic appearance of the fracture surfaces of tested instruments revealed ductile fracture of cyclic fatigue failure. XPS instruments exhibited greater cyclic fatigue resistance compared with the other tested instruments. XP-endo Shaper instruments could be used more safely in curved canals due to their higher fatigue resistance.

  9. Thermal aging effects on the microstructure, oxidation behavior, and mechanical properties of as-cast nickel aluminide alloys

    Science.gov (United States)

    Lee, Dongyun

    The thermal aging effects on the microstructure, oxidation behavior at 900° and 1100°C, and mechanical properties of IC221M (Ni3Al based intermetallic alloy, ASTM A1002-99) were investigated. The microstructure consists of dendritic arms of the gamma (nickel solid solution) phase containing cube-shape gamma' (Ni3Al precipitates. The interdendritic regions are mostly gamma' (Ni3Al with up to 8 vol.% gamma + Ni5Zr eutectic constituents. Thermal aging effects on the microstructures and how microsegregation affects the oxidation behavior were examined. Four primary changes in the microstructures were observed: (1) there is considerable homogenization of the cast microstructures with aging, (2) the volume fraction of gamma' increases with aging time and temperature, (3) the gamma' phase coarsens, and (4) the volume fraction of the gamma + Ni5Zr eutectic constituents decreases. During the initial stages of oxidation at 900°C, surface oxides form along the microsegregation patterns, revealing the cast microstructures. The first oxide to form is mostly NiO with small amounts of Cr2O 3, ZrO2, NiCr2O4, and theta-Al 2O3. Initial oxidation occurs primarily in the interdendritic regions due to microsegregation of alloying elements during casting. With further aging, the predominant surface oxides become NiO and NiAl2O 4 spinel, with a continuous film of alpha-Al2O3 forming immediately beneath them. Although these oxides are constrained to the near surface region, other oxides penetrate to greater depths, facilitated by oxidation of the gamma + Ni5Zr eutectic constituents. These oxides appear in the microstructure as long, thin spikes of ZrO2 surrounded by a sheath of Al2O3. They can penetrate to depths greater than 10 times that of the continuous surface oxide. The oxidation behavior at 1100°C is similar to that at 900°C, but the oxidation kinetics are faster, NiO dominates at all aging periods, and the surface oxides do not adhere to the matrix meaning that a protective

  10. The cost of nickel allergy

    DEFF Research Database (Denmark)

    Hamann, Carsten R; Hamann, Dathan; Hamann, Curtis

    2013-01-01

    Background. Nickel is widely used in coins; nickel may cause contact allergy and allergic contact dermatitis in those who handle them. Objectives. To investigate alloy use, coin composition and nickel and cobalt release for a worldwide selection of currently circulating coins. Materials and methods...

  11. Dissimilar welding of nickel-based Alloy 690 to SUS 304L with Ti addition

    Science.gov (United States)

    Lee, H. T.; Jeng, S. L.; Yen, C. H.; Kuo, T. Y.

    2004-10-01

    This study investigates the effects of Ti addition on the weldability, microstructure and mechanical properties of a dissimilar weldment of Alloy 690 and SUS 304L. Shielding metal arc welding (SMAW) is employed to butt-weld two plates with three welding layers, where each layer is deposited in a single pass. To investigate the effects of Ti addition, the flux coatings of the electrodes used in the welding process are modified by varying additions of either a Ti-Fe compound or a Ti powder. The results indicate that the microstructure of the fusion zone (FZ) is primarily dendritic. With increasing Ti content, it is noted that the microstructure changes from a columnar dendritic to an equiaxed dendritic, in which the primary dendrite arm spacing (PDAS) becomes shorter. Furthermore, it is observed that the amount of Al-Ti oxide phase increases in the inter-dendritic region, while the amount of Nb-rich phase decreases. Moreover, the average hardness of the FZ increases slightly. The results indicate that Ti addition prompts a significant increase in the elongation of the weldment (i.e. 36.5%, Ti: 0.41 wt%), although the tensile strength remains relatively unchanged. However, at an increased Ti content of 0.91 wt%, an obvious reduction in the tensile strength is noted, which can be attributed to a general reduction in the weldability of the joint.

  12. High bandgap III-V alloys for high efficiency optoelectronics

    Energy Technology Data Exchange (ETDEWEB)

    Alberi, Kirstin; Mascarenhas, Angelo; Wanlass, Mark

    2017-01-10

    High bandgap alloys for high efficiency optoelectronics are disclosed. An exemplary optoelectronic device may include a substrate, at least one Al.sub.1-xIn.sub.xP layer, and a step-grade buffer between the substrate and at least one Al.sub.1-xIn.sub.xP layer. The buffer may begin with a layer that is substantially lattice matched to GaAs, and may then incrementally increase the lattice constant in each sequential layer until a predetermined lattice constant of Al.sub.1-xIn.sub.xP is reached.

  13. Comparative Evaluation of Metal-ceramic Bond Strengths of Nickel Chromium and Cobalt Chromium Alloys on Repeated Castings: An In vitro Study.

    Science.gov (United States)

    Atluri, Kaleswara Rao; Vallabhaneni, Tapan Teja; Tadi, Durga Prasad; Vadapalli, Sriharsha Babu; Tripuraneni, Sunil Chandra; Averneni, Premalatha

    2014-09-01

    Recasting the base metal alloys is done as a routine procedure in the dental laboratories whenever there is casting failure or to decrease the unit cost of a fixed partial denture. However, this procedure may affect the metal ceramic bond. Furthermore, it is unclear, as to which test closely predicts the bond strength of metal-ceramic interface. The aim was to compare the bond strength of nickel chromium (Ni-Cr) and cobalt chromium (Co-Cr) alloys with dental ceramic on repeated castings using shear bond test with a custom made apparatus. Sixty metal ceramic samples were prepared using Wiron 99 and Wirobond C, respectively. Three subgroups were prepared for each of the groups. The first subgroup was prepared by casting 100% fresh alloy. The second and third subgroups were prepared by adding 50% of fresh alloy and the remnants of the previous cast alloy. The bond load (N) between alloy and dental porcelain was evaluated using universal testing machine using a crosshead speed of 1 mm/min, which had a 2500-kgf load cell. Mean values were compared using oneway analysis of variance with post-hoc Tukey's test and Student's t-test. The mean shear bond load of A0 (842.10N) was significantly higher than the load of A1 (645.50N) and A2 (506.28N). The mean shear bond load of B0 (645.57N) was significantly higher than the load of B1 (457.35N) and B2 (389.30N). Significant reduction in the bond strength was observed with the addition of the first recast alloy (A1 and B1) compared with the addition of second recast alloy (A2 and B2). Ni-Cr alloys (664.63N) showed higher bond strengths compared to that of Co-Cr alloys (497.41N). The addition of previously used base metal dental alloy for fabricating metal ceramic restorations is not recommended.

  14. Localized corrosion of high performance metal alloys in an acid/salt environment

    Science.gov (United States)

    Macdowell, L. G.; Ontiveros, C.

    1991-01-01

    Various vacuum jacketed cryogenic supply lines at the Space Shuttle launch site at Kennedy Space Center use convoluted flexible expansion joints. The atmosphere at the launch site has a very high salt content, and during a launch, fuel combustion products include hydrochloric acid. This extremely corrosive environment has caused pitting corrosion failure in the thin walled 304L stainless steel flex hoses. A search was done to find a more corrosion resistant replacement material. The study focussed on 19 metal alloys. Tests which were performed include electrochemical corrosion testing, accelerated corrosion testing in a salt fog chamber, and long term exposure at a beach corrosion testing site. Based on the results of these tests, several nickel based alloys were found to have very high resistance to this corrosive environment. Also, there was excellent agreement between the electrochemical tests and the actual beach exposure tests. This suggests that electrochemical testing may be useful for narrowing the field of potential candidate alloys before subjecting samples to long term beach exposure.

  15. DEVELOPMENT OF CERTIFIED REFERENCE MATERIALS OF HEAT RESISTING NICKEL ALLOYS FOR DETERMINATION OF DETRIMENTAL IMPURITIES AND RARE EARTH ELEMENTS BY SPECTRAL METHODS

    Directory of Open Access Journals (Sweden)

    2015-01-01

    Full Text Available Results of development and certification of reference materials of composition of heat resisting nickel alloy with the certified values of content of detrimental impurities (Zn, Cd, Pb, Tl, Bi, In, Ag, Sb, Ga, Ge, As, Se, Sn, Te, Mn, Cu, rare earth elements (Pr, Nd, Dy, Gd, Ho, Er, Nb, Sc, Y, La, Ce, and also other impurities (P, B, Fe, Si, V, Ru, Zr, Hf, Ca, Mg are given. Developed CRMs are used for calibration of optical emission spectrometers, mass-spectrometers with glow discharge and laser sampling and others.

  16. Closed system Fischer-Tropsch synthesis over meteoritic iron, iron ore and nickel-iron alloy. [deuterium-carbon monoxide reaction catalysis

    Science.gov (United States)

    Nooner, D. W.; Gibert, J. M.; Gelpi, E.; Oro, J.

    1976-01-01

    Experiments were performed in which meteoritic iron, iron ore and nickel-iron alloy were used to catalyze (in Fischer-Tropsch synthesis) the reaction of deuterium and carbon monoxide in a closed vessel. Normal alkanes and alkenes and their monomethyl substituted isomers and aromatic hydrocarbons were synthesized. Iron oxide and oxidized-reduced Canyon Diablo used as Fischer-Tropsch catalysts were found to produce aromatic hydrocarbons in distributions having many of the features of those observed in carbonaceous chondrites, but only at temperatures and reaction times well above 300 C and 6-8 h.

  17. Analysis of components depth profile at the interface of Ti6242 alloy and TiNi coatings after high temperature oxidation in air

    Energy Technology Data Exchange (ETDEWEB)

    Galdikas, A. [Department of Physics and Mathematics, Kaunas University of Medicine (Lithuania); Riviere, J.P.; Pichon, L. [Laboratoire de Physique des Materiaux, University of Poitiers, Poitiers (France); Petraitiene, A.; Moskalioviene, T. [Physics Department, Kaunas University of Technology, 50 Studentu st., Kaunas (Lithuania)

    2010-11-15

    We have analyzed the interfacial elemental depth profile evolution after high temperature isothermal oxidation of NiTi coatings deposited by dynamic ion mixing on a Ti6242 alloy (Ti-6Al-2Sn-4Zr-2Mo). NiTi coatings (thickness 0.4 {mu}m) were deposited at room temperature (RT) by ion beam sputtering. High temperature isothermal oxidation tests in 1 atm flowing synthetic air (80% N{sub 2}, 20% O{sub 2}) have been conducted at 500 C and 600 C during 100 hours. We have observed a non-monotonous depth distribution of nickel in GDOES depth profiles after oxidation of TiNi/Ti6242: nickel segregates to the surface of TiNi coating and to the interface between TiNi coating and Ti6242 alloy. We propose a kinetic model based on rate equations for analyzing the depth profile. This model includes microprocesses taking place during oxidation in air such as: adsorption of nitrogen and oxygen, diffusion of components through the film and interface, formation of chemical compounds. It is shown by modeling that non-monotonous depth profile of nickel occurs because nickel from TiNi coating is forming a nickel oxide compound when oxygen atoms reach the film/alloy interface. XRD analysis confirms the presence of nickel oxide in the TiNi/Ti6242 interface after oxidation at both temperatures 500 C and 600 C (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Structural Properties of High Speed Electrodeposited Ni-Co Alloy Film on Titanium

    Science.gov (United States)

    Xie, Kan; Hussain, Mohammad Sakhawat; Ayres, Virginia

    A new and innovative high-speed process for direct electrodeposition of Ni-Co alloy on titanium surfaces without any pretreatment or displacement reaction has recently been reported. Investigations of the non-columnar growth mechanism(s) that result in high-speed adhesive coating formation are presented. Our results indicate that deposition of nanocrystalline nickel throughout the entire film growth process plays a critical role. When present, local nanowire formation is interpreted in terms of super-saturated conditions. Titanium is a metal that finds use in a wide variety of applications as a structural material in aircrafts, engines, missiles, bicycles and load-bearing bone prostheses. Conventional pretreatment methods to remove a thin tenacious oxide layer and then cap the surface with a sacrificial layer are dangerous, time-consuming and environmentally unfriendly. Extensions of the new high speed method to additional thin film systems are considered.

  19. A new strategy to improve the high-rate performance of hydrogen storage alloys with MoS2 nanosheets

    Science.gov (United States)

    Chen, L. X.; Zhu, Y. F.; Yang, C. C.; Chen, Z. W.; Zhang, D. M.; Jiang, Q.

    2016-11-01

    The poor high-rate dischargeability of negative electrode materials (hydrogen storage alloys) has hindered applications of nickel metal hydride batteries in high-power fields, new-energy vehicles, power tools, military devices, etc. In this work, a new strategy is developed to improve the high-rate performance of hydrogen storage alloys by coating MoS2 nanosheets on alloy surfaces. The capacity retention rate of the composite electrode reaches 50.5% at a discharge current density of 3000 mA g-1, which is 2.7 times that of bare alloy (18.4%). The density functional theory simulations indicate that such an outstanding performance is derived from adjustments of ion concentrations at the electrode/electrolyte interface by MoS2 nanosheets: (1) the higher OH- concentration facilitates the electrochemical reaction of MHads + OH- - e- → M + H2O; and (2) the lower H+ concentration leads to a large gradient between the electrode/electrolyte interface and interior of alloys, which is beneficial for the diffusion of atomic hydrogen during the discharging process.

  20. Microstructure and Mechanical Behavior of High-Entropy Alloys

    Science.gov (United States)

    Licavoli, Joseph J.; Gao, Michael C.; Sears, John S.; Jablonski, Paul D.; Hawk, Jeffrey A.

    2015-10-01

    High-entropy alloys (HEAs) have generated interest in recent years due to their unique positioning within the alloy world. By incorporating a number of elements in high proportion, usually of equal atomic percent, they have high configurational entropy, and thus, they hold the promise of interesting and useful properties such as enhanced strength and alloy stability. The present study investigates the mechanical behavior, fracture characteristics, and microstructure of two single-phase FCC HEAs CoCrFeNi and CoCrFeNiMn with some detailed attention given to melting, homogenization, and thermo-mechanical processing. Ingots approaching 8 kg in mass were made by vacuum induction melting to avoid the extrinsic factors inherent to small-scale laboratory button samples. A computationally based homogenization heat treatment was given to both alloys in order to eliminate any solidification segregation. The alloys were then fabricated in the usual way (forging, followed by hot rolling) with typical thermo-mechanical processing parameters employed. Transmission electron microscopy was subsequently used to assess the single-phase nature of the alloys prior to mechanical testing. Tensile specimens (ASTM E8) were prepared with tensile mechanical properties obtained from room temperature through 800 °C. Material from the gage section of selected tensile specimens was extracted to document room and elevated temperature deformation within the HEAs. Fracture surfaces were also examined to note fracture failure modes. The tensile behavior and selected tensile properties were compared with results in the literature for similar alloys.

  1. Laser assisted high entropy alloy coating on aluminum: Microstructural evolution

    Energy Technology Data Exchange (ETDEWEB)

    Katakam, Shravana; Joshi, Sameehan S.; Mridha, Sanghita; Mukherjee, Sundeep; Dahotre, Narendra B., E-mail: Narendra.Dahotre@unt.edu [Department of Materials Science and Engineering, University of North Texas, 1150 Union Circle, 305310 Denton, Texas 76203-5017 (United States)

    2014-09-14

    High entropy alloy (Al-Fe-Co-Cr-Ni) coatings were synthesized using laser surface engineering on aluminum substrate. Electron diffraction analysis confirmed the formation of solid solution of body centered cubic high entropy alloy phase along with phases with long range periodic structures within the coating. Evolution of such type of microstructure was a result of kinetics associated with laser process, which generates higher temperatures and rapid cooling resulting in retention of high entropy alloy phase followed by reheating and/or annealing in subsequent passes of the laser track giving rise to partial decomposition. The partial decomposition resulted in formation of precipitates having layered morphology with a mixture of high entropy alloy rich phases, compounds, and long range ordered phases.

  2. Nickel: makes stainless steel strong

    Science.gov (United States)

    Boland, Maeve A.

    2012-01-01

    Nickel is a silvery-white metal that is used mainly to make stainless steel and other alloys stronger and better able to withstand extreme temperatures and corrosive environments. Nickel was first identified as a unique element in 1751 by Baron Axel Fredrik Cronstedt, a Swedish mineralogist and chemist. He originally called the element kupfernickel because it was found in rock that looked like copper (kupfer) ore and because miners thought that "bad spirits" (nickel) in the rock were making it difficult for them to extract copper from it. Approximately 80 percent of the primary (not recycled) nickel consumed in the United States in 2011 was used in alloys, such as stainless steel and superalloys. Because nickel increases an alloy's resistance to corrosion and its ability to withstand extreme temperatures, equipment and parts made of nickel-bearing alloys are often used in harsh environments, such as those in chemical plants, petroleum refineries, jet engines, power generation facilities, and offshore installations. Medical equipment, cookware, and cutlery are often made of stainless steel because it is easy to clean and sterilize. All U.S. circulating coins except the penny are made of alloys that contain nickel. Nickel alloys are increasingly being used in making rechargeable batteries for portable computers, power tools, and hybrid and electric vehicles. Nickel is also plated onto such items as bathroom fixtures to reduce corrosion and provide an attractive finish.

  3. Magnesium Diecasting Alloys for High Temperature Applications

    Science.gov (United States)

    Pekguleryuz, Mihriban O.; Kaya, A. Arslan

    New growth area for automotive use of magnesium is powertrain applications such as the transmission case and engine block. These applications see service conditions in the temperature range of 150-200C under 50-70 MPa of tensile and compressive loads. In addition, metallurgical stability, fatigue resistance, corrosion resistance and castability requirements need to be met. A decade of research and development has resulted in a number of creep- resistant magnesium alloys that are potential candidates for elevated-temperature automotive applications. These alloys are mostly based on rare-earth and alkaline earth element additions to magnesium. This paper gives an overview of the various magnesium alloy systems for use in elevated-temperature applications.

  4. A computational investigation of the effect of alloying elements on the thermodynamic and diffusion properties of fcc nickel alloys, with application to the creep rate of dilute nickel-X alloys

    Science.gov (United States)

    Zacherl, Chelsey L.

    In this dissertation, two computational techniques have been employed to understand the alloying effects of various transition elements in Ni and its alloys. To aid in the process of narrowing down the large composition space for the design of future Ni-base superalloys, a thermodynamic model using the CALPHAD approach is developed, where Gibbs energy functions of individual phases are parameterized based on fittings to experimentally measured phase equilibria or thermochemical data and computationally predicted thermochemical data. Multi-component Ni-base superalloys can be accurately described within the CALPHAD approach through the extrapolation of the Gibbs energy functions of the simpler sub-systems which are modeled where experimental and computational data is usually more abundant. The Re-Y and Re-Ti systems, integral binary alloy systems in the Ni-base superalloy database, are modeled in the present work. In addition to studying thermodynamic and phase stability properties of Ni-base superalloys, this thesis also highlights the importance of the kinetic properties of these materials through their diffusion coefficients. Vacancy mediated self-diffusion coefficients are calculated on ferromagnetic and non-magnetic fcc Ni as a function of temperature. Within Eyring’s reaction rate theory, minimum energy pathways for the diffusing atom is calculated using the Nudged Elastic Band method. The present work demonstrates that the mid-row 5d transition row element impurities have the highest activation barriers for impurity diffusion, and subsequently are the slowest diffusers in Ni. The fastest diffusers in Ni coupled with the lowest activation barriers for impurity diffusion are demonstrated to be at the far left of the 3d and 4d transition element rows on the periodic table. The present work also demonstrates that the primary mechanism driving the variation in the impurity diffusion coefficient from element to element is the migration barrier for impurity

  5. High frequency fatigue test of IN 718 alloy – microstructure and fractography evaluation

    Directory of Open Access Journals (Sweden)

    J. Belan

    2015-01-01

    Full Text Available INCONEL alloy 718 is a high-strength, corrosion-resistant nickel chromium material used at -253 °C to 705 °C for production of heat resistant parts of aero jet engine mostly. The fatigue test provided on this kind materials were done via low frequency loading up to this time. Nowadays, needs of results at higher volume of loading cycles leads to high frequency loading with aim to shorten testing time. Fatigue test of experimental material was carried out at frequency 20 kHz with stress ration R = - 1 (push – pull at room temperature. It was found that this superalloy can still fracture after exceeding 108 cycles. Besides fatigue test were microstructural characterisation and scanning electron microscopy (SEM fractography evaluation done.

  6. Characterization of nickel-copper alloy specimens processed as a part of the M553 sphere forming experiment during the Skylab 1 and 2 flight

    Science.gov (United States)

    Hubbard, J. L.; Johnson, J. W.; Brown, J. L.

    1973-01-01

    Both processed nickel-copper alloy specimens apparently completely melted by the electron beam in the Skylab M512 materials processing facility and either floated free in space, but collided with some smooth flat surface before solidifying, or remained attached to its support post during solidification. Both specimens had a smooth flat area on the surface due to this adherence during solidification. The nominal composition of the alloy before processing in space was 70 percent Ni and 30 percent Cu. Tests show that a considerable amount of copper was lost during processing by evaporation. It was further found that less copper was present in the cap areas, particularly at the surface, than was in the remainder of the specimens. The microchemistry of the dendrites and interdendritic regions, however, is in agreement with the phase diagram for this alloy. The measured densities of these specimens were less than the theoretical density of the alloy due to the amount of porosity present, however, no large voids were found by radiographic techniques.

  7. Design criteria for rhenium-reduced nickel-based single-crystal alloys. Identification and computer-assisted conversion; Designkriterien fuer rheniumreduzierte Nickelbasis-Einkristalllegierungen. Identifikation und rechnergestuetzte Umsetzung

    Energy Technology Data Exchange (ETDEWEB)

    Goehler, Thomas

    2016-06-17

    In the present work, design criteria and property models for the creep strength optimization of rhenium-free nickel based single crystal Superalloys are investigated. The study focuses on a typical load condition of 1050 C and 150 MPa, which is representative for flight engine applications. Thereby the key aspect is to link chemical composition, manufacturing processes, microstructure formation and mechanistic understanding of dislocation creep through a computational materials engineering approach. Beside the positive effect of rhenium on solid solution hardening, a second mechanism in which rhenium increases high temperature creep strength is identified. It indirectly stabilizes precipitation hardening by reducing the coarsening kinetics of γ'-rafting. Five 1st and 2nd generation technical Superalloys show a comparable microstructure evolution for up to 2 % plastic elongation, while creep times differ by a factor of five. The application of a microstructure sensitive creep model shows that these coarsening processes can activate γ-cutting and thus lead to an increasing creep rate. Based on these calculations a threshold value of φ{sub γ/γ'} > 2,5 at 150 MPa is estimated. This ratio of matrix channel to raft thickness has been proofed for multiple positions by microstructure analysis of interrupted creep tests. The mechanism described previously can be decelerated by the enrichment of the γ-matrix with slow diffusing elements. The same principle also increases the solid solution strength of the γ-matrix. Therefore, the present work delivers an additional mechanistic explanation why creep properties of single phase nickel based alloys can be transferred to two phase technical Superalloys with rafted γ'-structure. Following, the best way to substitute both rhenium fundamental properties, namely a slow diffusion coefficient and a small solubility in g', has been investigated by means of CALPHAD-modeling. Only molybdenum and especially

  8. Corrosion resistance of stainless steel, nickel-titanium, titanium molybdenum alloy, and ion-implanted titanium molybdenum alloy archwires in acidic fluoride-containing artificial saliva: An in vitro study

    Directory of Open Access Journals (Sweden)

    Venith Jojee Pulikkottil

    2016-01-01

    Full Text Available Objective: (1 To evaluate the corrosion resistance of four different orthodontic archwires and to determine the effect of 0.5% NaF (simulating high fluoride-containing toothpaste of about 2250 ppm on corrosion resistance of these archwires. (2 To assess whether surface roughness (Ra is the primary factor influencing the corrosion resistance of these archwires. Materials and Methods: Four different archwires (stainless steel [SS], nickel-titanium [NiTi], titanium molybdenum alloy [TMA], and ion-implanted TMA were considered for this study. Surface characteristics were analyzed using scanning electron microscopy, atomic force microscopy (AFM, and energy dispersive spectroscopy. Linear polarization test, a fast electrochemical technique, was used to evaluate the corrosion resistance, in terms of polarization resistance of four different archwires in artificial saliva with NaF concentrations of 0% and 0.5%. Statistical analysis was performed by one-way analysis of variance. Results: The potentiostatic study reveals that the corrosion resistance of low-friction TMA (L-TMA > TMA > NiTi > SS. AFM analysis showed the surface Ra of TMA > NiTi > L-TMA > SS. This indicates that the chemical composition of the wire is the primary influential factor to have high corrosion resistance and surface Ra is only secondary. The corrosion resistance of all wires had reduced significantly in 0.5% acidic fluoride-containing artificial saliva due to formation of fluoride complex compound. Conclusion: The presence of 0.5% NaF in artificial saliva was detrimental to the corrosion resistance of the orthodontic archwires. Therefore, complete removal of residual high-fluorinated toothpastes from the crevice between archwire and bracket during tooth brushing is mandatory.

  9. Thermal conductivity, electrical resistivity and Seebeck coefficient of high purity iron and selected iron alloys from 90 K to 400 K. [Fe--1. 14 Cr, Fe--2. 96 Cr, Fe--1. 15 Cr--1. 30 Ni, and Fe--3. 15 Ni

    Energy Technology Data Exchange (ETDEWEB)

    Holder, T.K.

    1977-06-01

    The thermal conductivity, electrical resistivity, and Seebeck coefficient of high-purity iron, two iron--chromium alloys, one iron--nickel alloy, and one iron--chromium--nickel alloy were measured over the temperature range from 90 K to 400 K. Smoothed values for the thermal conductivity and electrical resistivity were used to calculate the electronic thermal conductivity, the lattice conductivity, and the Lorenz function by means of a binary alloy separation technique. The lattice conductivity and Lorenz function exhibited little change due to the addition of chromium; however, the addition of small amounts of nickel resulted in significant property changes. The lattice conductivity at high temperatures was calculated from theory and compared to experimental results. Good agreement between theory and experimental data was obtained. 17 figures, 29 tables.

  10. Influence of oxidation on the high-temperature mechanical properties of zirconia/nickel cermets

    Energy Technology Data Exchange (ETDEWEB)

    Morales-Rodriguez, A. [Departamento de Fisica de la Materia Condensada, Universidad de Sevilla, Av. Reina Mercedes s/n, Facultad de Fisica, 41012 Seville (Spain)]. E-mail: amr@us.es; Bravo-Leon, A. [Departamento de Fisica de la Materia Condensada, Universidad de Sevilla, Av. Reina Mercedes s/n, Facultad de Fisica, 41012 Seville (Spain); Richter, G. [Max-Planck-Institut fuer Metallforschung, Stuttgart (Germany); Ruehle, M. [Max-Planck-Institut fuer Metallforschung, Stuttgart (Germany); Dominguez-Rodriguez, A. [Departamento de Fisica de la Materia Condensada, Universidad de Sevilla, Av. Reina Mercedes s/n, Facultad de Fisica, 41012 Seville (Spain); Jimenez-Melendo, M. [Departamento de Fisica de la Materia Condensada, Universidad de Sevilla, Av. Reina Mercedes s/n, Facultad de Fisica, 41012 Seville (Spain)

    2006-06-15

    influence of an oxidizing atmosphere on the high-temperature plasticity of zirconia/nickel cermets has been studied by conducting creep tests in air. The resulting microstructure has been characterized by scanning, conventional and high-resolution electron microscopy. Despite the large microstructural changes, the composites do not exhibit mechanical degradation.

  11. Experimental determination of Poisson's ratio of a single crystal nickel heat-resistant alloy in the temperature range of 20-1000°C

    Science.gov (United States)

    Golynets, S. A.; Toloraiya, V. N.; Nekrasov, S. N.; Khvatskii, K. K.

    2017-09-01

    This work is devoted to the experimental determination of Poisson's ratio at temperatures of 20-1000°C, which was carried out on cylindrical samples of a single-crystal heat-resistant nickel alloy with crystallographic orientations of (CGOs) [001], [011], and [111]. The modulus of elasticity for the samples of these orientations has also been determined. It has been established that, in samples of heat-resistant nickel singlecrystal alloy with CGO [011], Poisson's ratio can vary from negative to positive values depending on the azimuthal orientation, i.e., on the crystallographic directions that lie in the plane perpendicular to the longitudinal axis of the sample. To control the azimuthal CGO of cylindrical samples [011], a special metallographic procedure was developed based on the determination of the dendritic structure on the butt ends of these samples using etching. The data on the azimuthal orientation were subsequently used to place a sensor in order to determine the transverse deformation in these directions.

  12. DEVELOPMENT OF NEW VALVE STEELS FOR APPLICATION IN HIGH PERFORMANCE ENGINES

    Directory of Open Access Journals (Sweden)

    Alexandre Bellegard Farina

    2013-12-01

    Full Text Available UNS N07751 and UNS N07080 alloys are commonly applied for automotive valves production for high performance internal combustion engines. These alloys present high hot resistance to mechanical strength, oxidation, corrosion, creep and microstructural stability. However, these alloys presents low wear resistance and high cost due to the high nickel contents. In this work it is presented the development of two new Ni-based alloys for application in high performance automotive valve as an alternative to the alloys UNS N07751 and UNS N07080. The new developed alloys are based on a high nickel-chromium austenitic matrix with dispersion of γ’ and γ’’ phases and containing different NbC contents. Due to the nickel content reduction in the developed alloys in comparison with these actually used alloys, the new alloys present an economical advantage for substitution of UNS N07751 and UNS N0780 alloys.

  13. In-situ Raman spectroscopic study of nickel-base alloy in nuclear power plants and its implications to SCC

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji Hyun [Massachusetts Institute of Technology, Cambridge (United States); Bahn, Chi Bum; Hwang, Il Soon [Seoul National University, Seoul (Korea, Republic of)

    2004-10-15

    Although there has been no general agreement on the mechanism of primary water stress corrosion cracking (PWSCC) as one of major degradation modes of Ni-base alloys in pressurized water reactors (PWR's), common postulation derived from previous studies is that the damage to the alloy substrate can be related to mass transport characteristics and/or repair properties of overlaid oxide film. Recently, it was shown that the oxide film structure and PWSCC initiation time as well as crack growth rate were systematically varied as a function of dissolved hydrogen concentration in high temperature water, supporting the postulation. In order to understand how the oxide film composition can vary with water chemistry, this study was conducted to characterize oxide films on Alloy 600 by an in-situ Raman spectroscopy. Based on both experimental and thermodynamic prediction results, Ni/NiO thermodynamic equilibrium condition was defined as a function of electrochemical potential and temperature. The results agree well with Attanasio et al.'s data by contact electrical resistance measurements. The anomalously high PWSCC growth rate consistently observed in the vicinity of Ni/NiO equilibrium is then attributed to weak thermodynamic stability of NiO. Redox-induced phase transition between Ni metal and NiO may undermine the integrity of NiO and enhance presumably the percolation of oxidizing environment through the oxide film, especially along grain boundaries. The redox-induced grain boundary oxide degradation mechanism has been postulated and will be tested by using the in-situ Raman facility

  14. Nickel Dermatitis - Nickel Excretion

    DEFF Research Database (Denmark)

    Menné, T.; Thorboe, A.

    1976-01-01

    Nickel excretion in urine in four females -sensitive to nickel with an intermittent dyshidrotic eruption was measured with flameless atomic absorption. Excretion of nickel was found to be increased in association with outbreaks of vesicles. The results support the idea that the chronic condition...... was maintained by ingestion of nickel in food....

  15. [Experimental reconstruction of the canine trachea with shape-memory titanium-nickel alloy stent coupled with free jejunal graft].

    Science.gov (United States)

    Ma, Ling-guo; Wang, Yue-jian; He, Fa-yao; Zhang, Jian-li; Zhou, Xing

    2004-10-01

    To explore the reconstruction method of extensive circumferential tracheal defects longer than 6.0 cm and evaluate the influence on pulmonary function from jejunal secretion. Jejunal secretion model without extraneous nerve were established. 10 mongrel dogs were randomly divided into two groups. In group A, the nude stent made by shape-memory titanium-nickel alloy (SMA stent) was placed in the interior of the intestinal lumen. In group B, the SMA stent with silicone membrane was placed in the interior of the intestinal lumen. The secretion and histological chance of these jejunal were observed regularly. The cervical tracheal segment (6.5 cm) was replaced by the intestinal graft. In group C (6 mongrel dogs), the nude stent made by SMA stent was placed in the interior of the intestinal lumen. In group D (6 mongrel dogs and 6 Beagle dogs), the SMA stent with silicone membrane was placed in the interior of the intestinal lumen, the nude "C-shaped" SMA stent was placed out of the intestinal lumen, and the silicone stent was removed the fourth week after operation. In group C and group D, endoscopic and histological examinations were performed between the first week and eighth month. The secretory peak of Jejunal secretion model without extraneous nerve ranged from the first day to seventh day after operation. The jejunal secretion reduced gradually from 7th days after operation. The jejunal secretion remained steady after postoperative two months. In group C, endoscopic examination showed heavy proliferation of granulation in the tracheo-intestinal anastomosis. 4 dogs died between seventh day to second month. In group D, one dog died from ileus third month after operation. The other all survived operation. Gentle pneumonia happened to some dogs during 1-2 months after operation by X-ray examination. No one died of pneumonia result from hypersecretion. Reconstruction of the canine trachea with SMA stent with silicone membrane placed in the interior of the intestinal

  16. Highly Dispersed Nickel-Containing Mesoporous Silica with Superior Stability in Carbon Dioxide Reforming of Methane: The Effect of Anchoring.

    Science.gov (United States)

    Cai, Wenjia; Ye, Lin; Zhang, Li; Ren, Yuanhang; Yue, Bin; Chen, Xueying; He, Heyong

    2014-03-19

    A series of nickel-containing mesoporous silica samples (Ni-SiO₂) with different nickel content (3.1%-13.2%) were synthesized by the evaporation-induced self-assembly method. Their catalytic activity was tested in carbon dioxide reforming of methane. The characterization results revealed that the catalysts, e.g., 6.7%Ni-SiO₂, with highly dispersed small nickel particles, exhibited excellent catalytic activity and long-term stability. The metallic nickel particle size was significantly affected by the metal anchoring effect between metallic nickel particles and unreduced nickel ions in the silica matrix. A strong anchoring effect was suggested to account for the remaining of small Ni particle size and the improved catalytic performance.

  17. Highly Dispersed Nickel-Containing Mesoporous Silica with Superior Stability in Carbon Dioxide Reforming of Methane: The Effect of Anchoring

    Directory of Open Access Journals (Sweden)

    Wenjia Cai

    2014-03-01

    Full Text Available A series of nickel-containing mesoporous silica samples (Ni-SiO2 with different nickel content (3.1%–13.2% were synthesized by the evaporation-induced self-assembly method. Their catalytic activity was tested in carbon dioxide reforming of methane. The characterization results revealed that the catalysts, e.g., 6.7%Ni-SiO2, with highly dispersed small nickel particles, exhibited excellent catalytic activity and long-term stability. The metallic nickel particle size was significantly affected by the metal anchoring effect between metallic nickel particles and unreduced nickel ions in the silica matrix. A strong anchoring effect was suggested to account for the remaining of small Ni particle size and the improved catalytic performance.

  18. Analysis of phase transformation in high strength low alloyed steels

    OpenAIRE

    A. Di Schino

    2017-01-01

    The effect of low-alloy additions on phase transformation of high strength low alloyed steels is reported. Various as-quenched materials with microstructures consisting of low carbon (granular) bainitic, mixed bainitic/martensitic and fully martensitic microstructures were reproduced in laboratory. Results show that for a given cooling rate, an increase of austenite grain size (AGS) and of Mo and Cr contents decreases the transformation temperatures and promotes martensite formation.

  19. High temperature seals between ceramic separation membranes and super-alloy housing

    Science.gov (United States)

    Honea, G.; Sridhar, K. R.

    1991-01-01

    One of the concepts for oxygen production from Martian atmospheric carbon dioxide involves the use of tubular electrochemical membranes for oxygen separation. The tubular configuration offers the advantage of being able to separate the oxygen at pressures of up to 500 psi, thereby eliminating the need for a pre-liquefaction oxygen compressor. A key technology that has to be developed in order for the electrochemical separator to combine as a compressor is a high temperature static seal between the ceramic separation cell and the nickel-based super-alloy tube. Equipment was designed and fabricated to test the seals. Efforts are under way to develop a finite element model to study the thermal stresses at the joints and on the seal, and the optimal shape of the seal. The choice of seal materials and the technique to be used to fabricate the seals are also being investigated.

  20. Etude expérimentale du soudage par laser YAG de l'alliage base nickel Hastelloy X Experimental study of YAG laser welding of nickel base alloy Hastelloy X

    Directory of Open Access Journals (Sweden)

    Graneix Jérémie

    2013-11-01

    Full Text Available Le procédé de soudage laser YAG est envisagé pour remplacer le procédé de soudage TIG manuel pour la réalisation de pièces de turboréacteur en alliage nickel-chrome-molybdène Hastelloy X. Cette étude expérimentale a permis de définir un domaine de soudabilité de cet alliage répondant aux critères spécifiques du secteur aéronautique. The YAG laser welding process is contemplated to replace the manual TIG welding process for the production of parts of turbojet in Hastelloy X. This experimental study has identified the field of weldability of this alloy to meet the specific requirements of the aerospace industry.

  1. Spectral emissivity of candidate alloys for very high temperature reactors in high temperature air environment

    Energy Technology Data Exchange (ETDEWEB)

    Cao, G., E-mail: gcao@wisc.edu; Weber, S.J.; Martin, S.O.; Sridharan, K.; Anderson, M.H.; Allen, T.R.

    2013-10-15

    Emissivity measurements for candidate alloys for very high temperature reactors were carried out in a custom-built experimental facility, capable of both efficient and reliable measurements of spectral emissivities of multiple samples at high temperatures. The alloys studied include 304 and 316 austenitic stainless steels, Alloy 617, and SA508 ferritic steel. The oxidation of alloys plays an important role in dictating emissivity values. The higher chromium content of 304 and 316 austenitic stainless steels, and Alloy 617 results in an oxide layer only of sub-micron thickness even at 700 °C and consequently the emissivity of these alloys remains low. In contrast, the low alloy SA508 ferritic steel which contains no chromium develops a thicker oxide layer, and consequently exhibits higher emissivity values.

  2. Spectral emissivity of candidate alloys for very high temperature reactors in high temperature air environment

    Science.gov (United States)

    Cao, G.; Weber, S. J.; Martin, S. O.; Sridharan, K.; Anderson, M. H.; Allen, T. R.

    2013-10-01

    Emissivity measurements for candidate alloys for very high temperature reactors were carried out in a custom-built experimental facility, capable of both efficient and reliable measurements of spectral emissivities of multiple samples at high temperatures. The alloys studied include 304 and 316 austenitic stainless steels, Alloy 617, and SA508 ferritic steel. The oxidation of alloys plays an important role in dictating emissivity values. The higher chromium content of 304 and 316 austenitic stainless steels, and Alloy 617 results in an oxide layer only of sub-micron thickness even at 700 °C and consequently the emissivity of these alloys remains low. In contrast, the low alloy SA508 ferritic steel which contains no chromium develops a thicker oxide layer, and consequently exhibits higher emissivity values.

  3. High-throughput premix membrane emulsification using nickel sieves having straight-through pores

    NARCIS (Netherlands)

    Nazir, A.; Schroën, C.G.P.H.; Boom, R.M.

    2011-01-01

    We report on the use of nickel sieves, having a uniform pore size (typically 10 µm × 300 µm), for (oil-in-water) premix emulsification at relatively low transmembrane pressures. The droplet break-up was found to be based on elongation and recompression of droplets typical of high-pressure

  4. Hierarchical one-dimensional ammonium nickel phosphate microrods for high-performance pseudocapacitors

    CSIR Research Space (South Africa)

    Raju, K

    2015-12-01

    Full Text Available architecture makes them suitable for use in energy storage. For the first time, we report 1-D microrod structures (~ 36 nm width) of ammonium nickel phosphate hydrate (ANP(submr)) as a pseudocapacitor with high energy rating and power handling. To confirm...

  5. Quantification of the microstructures of high purity nickel subjected to dynamic plastic deformation

    DEFF Research Database (Denmark)

    Luo, Z.P.; Zhang, H.W.; Hansen, Niels

    2012-01-01

    A quantitative microstructural analysis is presented for pure polycrystalline nickel processed by means of dynamic plastic deformation at high strain rates (102–103 s−1) to strains from 0.3 to 2.9. This analysis covers a number of structural parameters, such as the spacing between...

  6. A comparison of corrosion-resistant steel (18 percent chromium - 8 percent nickel) and aluminum alloy (24st)

    Science.gov (United States)

    Sullivan, J E

    1936-01-01

    In the selection of materials for aircraft application, it is not enough to make the selection on a strength-weight basis alone. A strength-weight comparison is significant but other factors must be considered, for while a material with a high ratio of strength to weight may be perfectly satisfactory for one use, it may be totally unfitted for another. It is essential, among other things, that the probable nature, magnitude, and direction of the principal stresses be given special consideration. The following analysis has therefore been made with this in mind. An attempt has been made to cover insofar as possible the major, but not all the points, that a designer would consider in the use of "18-8", as it is commonly referred to, and 24ST aluminum alloy, as applied to aircraft. 24ST was selected for this comparison as it has practically replaced 17ST for aircraft construction and it appears to have the best combination of properties of the alloys now available for this purpose. The cost of fabrication has not been considered.

  7. Jewellery: alloy composition and release of nickel, cobalt and lead assessed with the EU synthetic sweat method.

    Science.gov (United States)

    Hamann, Dathan; Thyssen, Jacob P; Hamann, Carsten R; Hamann, Curtis; Menné, Torkil; Johansen, Jeanne D; Spiewak, Radoslaw; Maibach, Howard; Lundgren, Lennart; Lidén, Carola

    2015-10-01

    Several studies have shown nickel and cobalt release from jewellery by using spot tests, but the metal composition of jewellery is largely unknown. To evaluate the metal composition of a large worldwide sample of mainly inexpensive jewellery items, and investigate the release of nickel, cobalt and lead from a subsample by using EN 1811:1998-required methods. A total of 956 metallic jewellery components were examined with X-ray fluorescence spectroscopy. A subsample of 96 jewellery items purchased in the United States were investigated for nickel, cobalt and lead release by the use of artificial sweat immersion and plasma optical emission spectroscopy. Eighteen elements were detected. The 10 most frequently occurring were, in order of frequency, copper, iron, zinc, nickel, silver, chromium, tin, manganese, lead, and cobalt. Release of nickel was noted from 79 of the 96 US samples (0.01-98 µg/cm(2) /week), release of cobalt from 35 samples (0.02-0.5 µg/cm(2) /week), and release of lead from 37 samples (0.03-2718 µg/cm(2) /week). We present here a comprehensive list of the most frequently encountered metals in jewellery and fashion accessories. Different allergenic and non-allergenic metals are utilized. We also report the frequent release of nickel, cobalt and lead from these objects, despite legislative restrictions. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  8. In vitro element release and biological aspects of base?metal alloys for metal-ceramic applications

    OpenAIRE

    Holm, Charlotta; Morisbak, Else; Kalfoss, Torill; Dahl, Jon E.

    2015-01-01

    Abstract Objective: The aims of this study were to investigate the release of element from, and the biological response in vitro to, cobalt?chromium alloys and other base?metal alloys used for the fabrication of metal-ceramic restorations. Material and methods: Eighteen different alloys were investigated. Nine cobalt?chromium alloys, three nickel?chromium alloys, two cobalt?chromium?iron alloys, one palladium?silver alloy, one high-noble gold alloy, titanium grade II and one type III copper?a...

  9. Oxidation of CoCrFeMnNi High Entropy Alloys

    Science.gov (United States)

    Holcomb, Gordon R.; Tylczak, Joseph; Carney, Casey

    2015-06-01

    Eight model high entropy alloys (HEAs) in the CoCrFeMnNi family (including one alloy each in the CoCrFeNi and CoFeMnNi subfamilies) were made, prepared, and exposed to laboratory air for 1100 h at 650°C and 750°C. Two commercial alloys, nickel-base superalloy 230 (N06230) and austenitic stainless steel 304H (S30409), were simultaneously exposed for comparison. Mass change oxidation kinetics were measured and cross-sections of exposed samples were observed. Seven of these HEAs contained much more Mn (12-24 wt.%) than is found in commercial heat-resistant stainless steels and superalloys. The oxidation resistance of CoCrFeNi was excellent and comparable to 304H at 650°C and only slightly worse at 750°C. The thin oxide scale on CoCrFeNi was primarily Cr oxide (presumably Cr2O3) with some Mn oxide at the outer part of the scale. The CoCrFeMnNi HEAs all experienced more rapid oxidation than CoCrFeNi and, especially at 750°C, experienced oxide scale spallation. The addition of Y in the alloy to lower S improved the oxidation resistance of these HEAs. Alloy CoFeMnNi, without Cr, experienced much higher oxidation rates and scale spallation than the Cr-containing alloys. A linear regression analysis of the log of the parabolic rate constant, log(kp), as functions of wt.% Cr and Mn found a good correlation for the compositional dependence of the oxidation rate constant, especially at 650°C. Mn was found to be more detrimental increasing log(k p) than Cr was helpful reducing log(k p). If CoCrFeMnNi HEAs are to be used in high temperature oxidizing environments, then examining lower levels of Mn, while maintaining Cr levels, should be pursued.

  10. 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...

  11. The Production of Nickel-Chromium-Molybdenum Alloy with Open Pore Structure as an Implant and the Investigation of Its Biocompatibility In Vivo

    Directory of Open Access Journals (Sweden)

    Yusuf Er

    2013-01-01

    Full Text Available A dental crown material, Nickel-Chrome-Molybdenum alloy, is manufactured using precision casting method from a polyurethane foam model in a regular and open-pore form, as a hard tissue implant for orthopedic applications. The samples produced have 10, 20, and 30 (±3 pores per inch of pore densities and 0.0008, 0.0017, and 0.0027 g/mm3 densities, respectively. Samples were implanted in six dogs and observed for a period of two, four, and six months for the histopathological examinations. The dogs were examined radiologically in 15-day intervals and clinically in certain intervals. The implants were taken out with surrounding tissue at the end of these periods. Implants and surrounding tissues were examined histopathologically in terms of biocompatibility. As a result, it is seen that new bone tissue was formed, in pores of the porous implant at the head of the tibia in dogs implanted. Any pathology, inflammation, and reaction in old and new tissues were not observed. It was concluded that a dental alloy (Ni-Cr-Mo alloy could also be used as a biocompatible hard tissue implant material for orthopedics.

  12. High temperature oxidation of iron-chromium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Mikkelsen, Lars

    2003-06-15

    The high temperature oxidation of the ferritic alloy Fe78Cr22 has been investigated in the present work. The effect of small alloying additions of cerium and/or silicon was also investigated. The alloys were oxidized at 973, 1173 and 1373 K in either air or a hydrogen/argon mixture. The various reaction atmospheres contained between 0.02 and 50% water vapour. The oxide scales formed on the various alloys at 973 K consisted of thin chromia layers. The oxide scales grown on the alloys at 1173 K also consisted of a chromia layer. The microstructure of the chromia scales was found to depend on the reaction atmosphere. The chromia scales grown in hydrogen/argon atmospheres formed oxide whiskers and oxide ridges at the surface of the scales, while the chromia scales grown in air formed larger oxide grains near the surface. This difference in oxide microstructure was due to the vaporization of chromium species from the chromia scales grown in air. Two different growth mechanisms are proposed for the growth of oxide whiskers. The growth rate of the chromia scales was independent of the oxygen activity. This is explained by a growth mechanism of the chromia scales, where the growth is governed by the diffusion of interstitial chromium. The addition of silicon to the iron-chromium alloy resulted in the formation of silica particles beneath the chromia scale. The presence of silicon in the alloy was found to decrease the growth rate of the chromia scale. This is explained by a blocking mechanism, where the silica particles beneath the chromia scale partly block the outwards diffusion of chromium from the alloy to the chromia scale. The addition of cerium to the iron-chromium alloy improved the adhesion of the chromia scale to the alloy and decreased the growth rate of chromia. It was observed that the minimum concentration of cerium in the alloy should be 0.3 at.% in order to observe an effect of the cerium addition. The effect of cerium is explained by the &apos

  13. Microstructure Control of High-alloyed White Cast Iron

    Directory of Open Access Journals (Sweden)

    Kawalec M.

    2014-03-01

    Full Text Available This paper presents the results of studies of high-alloyed white cast iron modified with lanthanum, titanium, and aluminium-strontium. The samples were taken from four melts of high-vanadium cast iron with constant carbon and vanadium content and near-eutectic microstructure into which the tested inoculants were introduced in an amount of 1 wt% respective of the charge weight. The study included a metallographic examinations, mechanical testing, as well as hardness and impact resistance measurements taken on the obtained alloys. Studies have shown that different additives affect both the microstructure and mechanical properties of high-vanadium cast iron.

  14. Refractory High-Entropy Alloys (Postprint)

    Science.gov (United States)

    2010-06-23

    1763concentrations in the centers of dendrite arms, Cda, and inter- dendrite regions, Cidr , are also given in these tables. The distribution of elements in the...Cda/ Cidr [8], which values are given in Tables 3 and 4. In agreement with the EDS results, the dendrite arms in Alloy 1 are enriched with W and... Cidr , as well as comparison of these values with Caver and the partition coefficient K¼Cda/ Cidr , are also given. Concentrations (at.%) Nb Mo Ta W Average

  15. Lanthanum nickel aluminum alloy

    Science.gov (United States)

    Gruen, Dieter M.; Mendelsohn, Marshall H.; Dwight, Austin E.

    1979-01-01

    A ternary intermetallic compound capable of reversible sorption of hydrogen having the chemical formula LaNi.sub.5-x Al.sub.x, where x is in the range of about 0.01 to 1.5 and the method of storing hydrogen using the intermetallic compound.

  16. A study of the composition and microstructure of nanodispersed Cu-Ni alloys obtained by different routes from copper and nickel oxides

    Energy Technology Data Exchange (ETDEWEB)

    Cangiano, Maria de los A; Ojeda, Manuel W., E-mail: mojeda@unsl.edu.ar; Carreras, Alejo C.; Gonzalez, Jorge A.; Ruiz, Maria del C

    2010-11-15

    Mixtures of CuO and NiO were prepared by two different techniques, and then the oxides were reduced with H{sub 2}. Method A involved the preparation of mechanical mixtures of CuO and NiO using different milling and pelletizing processes. Method B involved the chemical synthesis of the mixture of CuO and NiO. The route used to prepare the copper and nickel oxide mixture was found to have great influence on the characteristics of bimetallic Cu-Ni particles obtained. Observations performed using the X-ray diffraction (XRD) technique showed that although both methods led to the Cu-Ni solid solution, the diffractogram of the alloy obtained with method A revealed the presence of NiO together with the alloy. The temperature-programmed reduction (TPR) experiments indicated that the alloy is formed at lower temperatures when using method B. The scanning electron microscopy (SEM) studies revealed notable differences in the morphology and size distribution of the bimetallic particles synthesized by different routes. The results of the electron probe microanalysis (EPMA) studies evidenced the existence of a small amount of oxygen in both cases and demonstrated that the alloy synthesized using method B presented a homogeneous composition with a Cu-Ni ratio close to 1:1. On the contrary, the alloy obtained using method A was not homogeneous in all the volume of the solid. The homogeneity depended on the mechanical treatment undergone by the mixture of the oxides. - Research Highlights: {yields}Study of the properties of Cu-Ni alloys synthesized by two different routes. {yields}Mixtures of Cu and Ni oxides prepared by two techniques were reduced with H{sub 2}. {yields}Mixtures of oxides were obtained by a mechanical process and the citrate-gel route. {yields}The characterizations were carried out by TPR, XRD, SEM and EPMA. {yields}The route used to prepare oxide mixtures influences on the Cu-Ni alloy obtained.

  17. High temperature strain of metals and alloys. Physical fundamentals

    Energy Technology Data Exchange (ETDEWEB)

    Levitin, V. [National Technical Univ., Zaporozhye (Ukraine)

    2006-07-01

    The author shows how new in-situ X-ray investigations and transmission electron microscope studies lead to novel explanations of high-temperature deformation and creep in pure metals, solid solutions and super alloys. This approach is the first to find unequivocal and quantitative expressions for the macroscopic deformation rate by means of three groups of parameters: substructural characteristics, physical material constants and external conditions. Creep strength of the studied uptodate single crystal super alloys is greatly increased over conventional polycrystalline super alloys. The contents of this book include: macroscopic characteristics of strain at high temperatures; experimental equipment and technique of in situ X-ray investigations; experimental data and structural parameters in deformed metals; sub-boundaries as dislocation sources and obstacles; the physical mechanism of creep and the quantitative structural model; simulation of the parameters evolution; system of differential equations; high-temperature deformation of industrial super alloys; single crystals of super alloys; effect of composition, orientation and temperature on properties; and creep of some refractory metals.

  18. Use of thermogravimetry and thermodynamic calculations for specifying chromium diffusion occurring in alloys containing chromium carbides during high temperature oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Berthod, Patrice, E-mail: Patrice.Berthod@univ-lorraine.fr; Conrath, Elodie

    2015-09-01

    The chromium diffusion is of great importance for the high temperature oxidation behaviour of the chromium-rich carbides-strengthened superalloys. These ones contain high chromium quantities for allowing them well resisting hot corrosion by constituting and maintaining a continuous external scale of chromia. Knowing how chromium can diffuse in such alloys is thus very useful for predicting the sustainability of their chromia-forming behaviour. Since Cr diffusion occurs through the external part of the alloy already affected by the previous steps of oxidation (decarburized subsurface) it is more judicious to specify this diffusion during the oxidation process itself. This was successfully carried out in this work in the case of a model chromia-forming nickel-based alloy containing chromium carbides, Ni(bal.)–25Cr–0.5C (in wt.%). This was done by specifying, using real-time thermogravimetry, the mass gain kinetic due to oxidation, and by combining it with the post-mortem determination of the Cr concentration profiles in subsurface. The values of D{sub Cr} thus obtained for 1000, 1050 and 1100 °C in the alloy subsurface are consistent with the values obtained in earlier works for similar alloy's chemical compositions. - Highlights: • A Ni25Cr0.50C alloy was oxidized at high temperature in a thermo-balance. • The mass gain files were analysed to specify the Cr{sub 2}O{sub 3} volatilization constant K{sub v}. • Concentration profiles were acquired to specify the chromium gradient. • The diffusion coefficient of chromium through the subsurface was deduced. • The obtained diffusion coefficient is consistent with values previously obtained.

  19. A Highly Sensitive Electrochemical Glucose Sensor By Nickel-Epoxy Electrode With Non-Enzymatic Sensor

    Directory of Open Access Journals (Sweden)

    Riyanto Riyanto

    2016-03-01

    Full Text Available The preparation of new sensor for glucose was based on the fact that glucose can be determined by non-enzymatic glucose oxidase. The Ni metals (99.98% purity, 0.5 mm thick, Aldrich Chemical Company was used to prepare Ni-Epoxy electrode. The Ni-epoxy electrodes were prepared in square cut of 1 cm and 1 mm by length and wide respectively. The Ni metal electrodes were connected to silver wire with silver conducting paint prior covered with epoxy gum. The prepared of nickel-epoxy modified electrode showed outstanding electro catalytic activity toward the oxidation of glucose in alkaline solution. The result from this research are correlation of determination using Nickel-Epoxyelectrode for electroanalysis of glucose in NaOH was R2 = 0.9984. LOQ, LOD and recovery of the Nickel-Epoxy electrode towards glucose were found to be 4.4 μM, 1.48 μM and 98.19%, respectively. The Nickel-Epoxy wire based electrochemical glucose sensor demonstrates good sensitivity, wide linear range, outstanding detection limit, attractive selectivity, good reproducibility, high stability as well as prominent feasibility use of non-enzymatic sensor for monitoring glucose in human urine owing to its advantages of low cost, simple preparation and excellent properties for glucose detection.

  20. Fabrication of Bulk Glassy Alloy Foams by High Pressure Hydrogen

    Science.gov (United States)

    Wada, Takeshi; Inoue, Akihisa

    Porous Pd42.5Cu30Ni7.5P20 bulk glassy alloy rods with porosities of up to 70% were successfully prepared by high pressure hydrogen of 15 MPa. The melt of Pd42.5Cu30Ni7.5P20 alloy kept under high pressure hydrogen absorbs hydrogen and subsequent water quenching of the melt causes the homogeneous dispersion of hydrogen bubbles, which was resulted from the decrease of hydrogen solubility with decrease of pressure. Annealing the hydrogen bubble containing sample at a supercooled liquid state under vacuum, the bubbles are allowed to expand due to the decrease of viscosity of metallic glass matrix. Pores expansion continues until glassy matrix crystallizes or the equilibration among pressure of the pores, pressure of the atmosphere and surface tension is achieved. By utilizing these phenomena, pores up to 80 m in diameters are homogeneously distributed over the whole cross-sectional area of a fully glassy matrix. Under compressive deformation, the porous alloys with porosities exceeding 40% did not show macroscopic fracture in a wide compressive strain range up to 0.6 whereas the non-porous alloy fractures instantly after elastic limit of about 0.02. Porous bulk glassy alloys exhibit higher plateau stress, lower Young‧s modulus and higher energy absorption capacity compared with the conventional crystalline metal foams.

  1. Corrosion-Resistant High-Entropy Alloys: A Review

    Directory of Open Access Journals (Sweden)

    Yunzhu Shi

    2017-02-01

    Full Text Available Corrosion destroys more than three percent of the world’s gross domestic product. Therefore, the design of highly corrosion-resistant materials is urgently needed. By breaking the classical alloy-design philosophy, high-entropy alloys (HEAs possess unique microstructures, which are solid solutions with random arrangements of multiple elements. The particular locally-disordered chemical environment is expected to lead to unique corrosion-resistant properties. In this review, the studies of the corrosion-resistant HEAs during the last decade are summarized. The corrosion-resistant properties of HEAs in various aqueous environments and the corrosion behavior of HEA coatings are presented. The effects of environments, alloying elements, and processing methods on the corrosion resistance are analyzed in detail. Furthermore, the possible directions of future work regarding the corrosion behavior of HEAs are suggested.

  2. Mechanism of competitive grain growth in a curvilinear channel of crystal-sorter during the orientational solidification of nickel-based heat-resistant alloy

    Science.gov (United States)

    Monastyrskiy, V. P.; Pozdnyakov, A. N.; Ershov, M. Yu.; Monastyrskiy, A. V.

    2017-07-01

    Using numerical simulation in the ProCAST program complex, the conditions of the solidification of heat-resistant nickel alloy in curvilinear channels of a ceramic mold have been investigated. It has been shown that, in practically important cases, the vector of the temperature gradient is oriented along the axis of the curvilinear channel. In a spiral crystal selector, a cyclic change in the preferred direction of growth occurs because of the cyclic change in the direction of the vector of the temperature gradient. The fact that the vector of the temperature gradient is almost always directed along the axis of the curvilinear channel makes it possible to govern the orientation of the vector of the temperature gradient in space and, therefore, to obtain a grain with the preferred crystallographic orientation. Based on the results of this investigation, a method of the grain selection with a desired azimuthal orientation is proposed.

  3. Synthesis and characterization of binder-free Cr{sub 3}C{sub 2} coatings on nickel-based alloys for molten fluoride salt corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Brupbacher, Michael C.; Zhang, Dajie [Department of Materials Science and Engineering, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Buchta, William M. [The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Graybeal, Mark L. [U.S. Army Research Laboratory, Aberdeen Proving Ground, MD 21005 (United States); Rhim, Yo-Rhin [The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Nagle, Dennis C. [Department of Materials Science and Engineering, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Spicer, James B., E-mail: spicer@jhu.edu [Department of Materials Science and Engineering, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States)

    2015-06-15

    Under various conditions, chromium carbides appear to be relatively stable in the presence of molten fluoride salts and this suggests that their use in corrosion resistant coatings for fluoride salt environments could be beneficial. One method for producing these coatings is the carburization of sprayed Cr coatings using methane-containing gaseous precursors. This process has been investigated for the synthesis of binder-free chromium carbide coatings on nickel-based alloy substrates for molten fluoride salt corrosion resistance. The effects of the carburization process on coating microstructure have been characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) in conjunction with energy dispersive spectroscopy (EDS). Both plasma-sprayed and cold-sprayed Cr coatings have been successfully converted to Cr{sub 3}C{sub 2}, with the mechanism of conversion being strongly influenced by the initial porosity in the as-deposited coatings.

  4. Amorphous Alloy Membranes for High Temperature Hydrogen Separation

    Energy Technology Data Exchange (ETDEWEB)

    Coulter, K. [Southwest Research Inst. (SwRI), San Antonio, TX (United States)

    2013-09-30

    At the beginning of this project, thin film amorphous alloy membranes were considered a nascent but promising new technology for industrial-scale hydrogen gas separations from coal- derived syngas. This project used a combination of theoretical modeling, advanced physical vapor deposition fabricating, and laboratory and gasifier testing to develop amorphous alloy membranes that had the potential to meet Department of Energy (DOE) targets in the testing strategies outlined in the NETL Membrane Test Protocol. The project is complete with Southwest Research Institute® (SwRI®), Georgia Institute of Technology (GT), and Western Research Institute (WRI) having all operated independently and concurrently. GT studied the hydrogen transport properties of several amorphous alloys and found that ZrCu and ZrCuTi were the most promising candidates. GT also evaluated the hydrogen transport properties of V, Nb and Ta membranes coated with different transition-metal carbides (TMCs) (TM = Ti, Hf, Zr) catalytic layers by employing first-principles calculations together with statistical mechanics methods and determined that TiC was the most promising material to provide catalytic hydrogen dissociation. SwRI developed magnetron coating techniques to deposit a range of amorphous alloys onto both porous discs and tubular substrates. Unfortunately none of the amorphous alloys could be deposited without pinhole defects that undermined the selectivity of the membranes. WRI tested the thermal properties of the ZrCu and ZrNi alloys and found that under reducing environments the upper temperature limit of operation without recrystallization is ~250 °C. There were four publications generated from this project with two additional manuscripts in progress and six presentations were made at national and international technical conferences. The combination of the pinhole defects and the lack of high temperature stability make the theoretically identified most promising candidate amorphous alloys

  5. Nickel resistance and chromatin condensation in Saccharomyces cerevisiae expressing a maize high mobility group I/Y protein.

    Science.gov (United States)

    Forzani, C; Loulergue, C; Lobréaux, S; Briat, J F; Lebrun, M

    2001-05-18

    Expression of a maize cDNA encoding a high mobility group (HMG) I/Y protein enables growth of transformed yeast on a medium containing toxic nickel concentrations. No difference in the nickel content was measured between yeast cells expressing either the empty vector or the ZmHMG I/Y2 cDNA. The ZmHMG I/Y2 protein contains four AT hook motifs known to be involved in binding to the minor groove of AT-rich DNA regions. HMG I/Y proteins may act as architectural elements modifying chromatin structure. Indeed, a ZmHMG I/Y2-green fluorescent protein fusion protein was observed in yeast nuclei. Nickel toxicity has been suggested to occur through an epigenetic mechanism related to chromatin condensation and DNA methylation, leading to the silencing of neighboring genes. Therefore, the ZmHMG I/Y2 protein could prevent nickel toxicity by interfering with chromatin structure. Yeast cell growth in the presence of nickel and yeast cells expressing the ZmHMG I/Y2 cDNA increased telomeric URA3 gene silencing. Furthermore, ZmHMG I/Y2 restored a wild-type level of nickel sensitivity to the yeast (Delta)rpd3 mutant. Therefore, nickel resistance of yeast cells expressing the ZmHMG I/Y2 cDNA is likely achieved by chromatin structure modification, restricting nickel accessibility to DNA.

  6. An evaluation of mechanical and high-temperature corrosion properties of Ni-Cr alloy with composition of alloying elements

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Sujin; Kim, Dongjin [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Helium is used as a coolant in a VHTR owing to its high thermal conductivity, inertness, and low neutron absorption. However, helium inevitably includes impurities that create an imbalance in the surface reactivity at the interface of the coolant and the exposed materials. As the Alloy 617 has been exposed to high temperatures at 950 .deg. C in the impure helium environment of a VHTR, degradation of material is accelerated and mechanical properties decreased. An alloy superior to alloy 617 should be developed. In this study, the mechanical and high-temperature corrosion properties for Ni-Cr alloys fabricated in laboratory were evaluated as a function of the grain boundary strengthening and alloying element composition. The mechanical property and corrosion property for Ni-Cr alloys fabricated in a laboratory were evaluated as a function of the main element composition. The ductility was increased and decreased by increasing the amount of Mo and Cr, respectively. Surface oxide was detached during the corrosion test, because there was not aluminum element in the alloy. Aluminum seems to act as an anti-corrosive role in Ni-based alloy. In conclusion, the addition of Al into the alloy is required to improvement of high temperature corrosion resistance.

  7. High temperature hardness of steels and iron-based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Torres, H., E-mail: torres@ac2t.at; Varga, M.; Ripoll, M. Rodríguez

    2016-08-01

    Hot hardness, related to the mechanical strength and wear resistance of materials at high temperatures, has been measured from room temperature up to 800 °C for a comprehensive set of iron-based alloys having different microstructures and chemical compositions. The results obtained suggest the existence of several softening regimes with increasing temperatures, also with a massive hardness drop observed to begin at temperatures close to 0.5 times the melting temperature for most of the chosen alloys. Austenitic steel grades were also observed to show a significant softening behaviour at moderate temperatures compared to ferritic and martensitic alloys, attributed to the dislocation dynamics of face cubic centred alloys. The exact nature of the temperature dependence shown by hardness has been proposed to adopt the form of an exponential Arrhenius equation. Another model suggested in the available literature is also discussed within this context. Additionally, the role of alloying elements has been correlated to the softening behaviour. Molybdenum or boron were found to slow down the softening behaviour, while carbide-forming elements such as vanadium and tungsten were found to be beneficial for room temperature hardness.

  8. High-temperature corrosion and applications of nickel and iron aluminides in coal-conversion power systems

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K. [Argonne National Lab., IL (United States); Tortorelli, P.F. [Oak Ridge National Lab., TN (United States)

    1996-10-01

    Nickel and iron aluminide intermetallics are being developed for use as structural materials and/or as cladding for conventional engineering alloys. In addition to strength advantages, these materials exhibit excellent resistance to corrosion in single- and multioxidant environments at elevated temperatures by the formation of slow-growing, adherent alumina scales. Corrosion resistance in a given environment is strongly dependent on the composition of the alloy and on the nature of the corrosive species prevalent in the service environment. This paper presents a comprehensive review of the current status of the corrosion performance of these intermetallics in oxidizing, sulfidizing, and multicomponent gas environments of typical coal-conversion systems. Mechanisms of scale development/breakdown, performance envelopes for long-term usage of these materials, approaches to modifying the surfaces of engineering alloys by cladding or coating them with intermetallics, and in-service experience with these materials are emphasized.

  9. High Work Output Ni-Ti-Pt High Temperature Shape Memory Alloys and Associated Processing Methods

    Science.gov (United States)

    Noebe, Ronald D. (Inventor); Draper, Susan L. (Inventor); Nathal, Michael V. (Inventor); Garg, Anita (Inventor)

    2009-01-01

    According to the invention, compositions of Ni-Ti-Pt high temperature, high force, shape memory alloys are disclosed that have transition temperatures above 100 C.; have narrow hysteresis; and produce a high specific work output.

  10. Separating the Influence of Environment from Stress Relaxation Effects on Dwell Fatigue Crack Growth in a Nickel-Base Disk Alloy

    Science.gov (United States)

    Telesman, J.; Gabb, T. P.; Ghosn, L. J.

    2016-01-01

    Both environmental embrittlement and crack tip visco-plastic stress relaxation play a significant role in determining the dwell fatigue crack growth (DFCG) resistance of nickel-based disk superalloys. In the current study performed on the Low Solvus High Refractory (LSHR) disk alloy, the influence of these two mechanisms were separated so that the effects of each could be quantified and modeled. Seven different microstructural variations of LSHR were produced by controlling the cooling rate and the subsequent aging and thermal exposure heat treatments. Through cyclic fatigue crack growth testing performed both in air and vacuum, it was established that four out of the seven LSHR heat treatments evaluated, possessed similar intrinsic environmental resistance to cyclic crack growth. For these four heat treatments, it was further shown that the large differences in dwell crack growth behavior which still persisted, were related to their measured stress relaxation behavior. The apparent differences in their dwell crack growth resistance were attributed to the inability of the standard linear elastic fracture mechanics (LEFM) stress intensity parameter to account for visco-plastic behavior. Crack tip stress relaxation controls the magnitude of the remaining local tensile stresses which are directly related to the measured dwell crack growth rates. It was hypothesized that the environmentally weakened grain boundary crack tip regions fail during the dwells when their strength is exceeded by the remaining local crack tip tensile stresses. It was shown that the classical creep crack growth mechanisms such as grain boundary sliding did not contribute to crack growth, but the local visco-plastic behavior still plays a very significant role by determining the crack tip tensile stress field which controls the dwell crack growth behavior. To account for the influence of the visco-plastic behavior on the crack tip stress field, an empirical modification to the LEFM stress

  11. A new high strength alloy for hydrogen fueled propulsion systems

    Science.gov (United States)

    Mcpherson, W. B.

    1986-01-01

    This paper describes the development of a high-strength alloy (1241 MPa ultimate and 1103 MPa yield, with little or no degradation in hydrogen) for application in advanced hydrogen-fueled rocket engines. Various compositions of the Fe-Ni-Co-Cr system with elemental additions of Cb, Ti and Al are discussed. After processing, notched tensile specimens were tested in 34.5-MPa hydrogen at room temperature, as the main screening test. The H2/air notch tensile ratio was used as the selection/rejection criterion. The most promising alloys are discussed.

  12. High temperature fracture characteristics of a nanostructured ferritic alloy (NFA)

    Science.gov (United States)

    Byun, Thak Sang; Kim, Jeoung Han; Yoon, Ji Hyun; Hoelzer, David T.

    2010-12-01

    The nanostructured ferritic alloys (NFAs) have been developed to improve high temperature strength and radiation resistance by refining grains and including nanoclusters. Among the key properties of NFAs needed to be assessed for advanced reactor applications the cracking resistance at high temperatures has not been well known. In this work, therefore, the high temperature fracture behavior has been investigated for the latest nanostructured ferritic alloy 14YWT (SM10). The fracture toughness of the alloy was above 140 MPa √m at low temperatures, room temperature (RT) and 200 °C, but decreased to a low fracture toughness range of 52-82 MPa √m at higher temperatures up to 700 °C. This behavior was explained by the fractography results indicating that the unique nanostructure of 14YWT alloy produced shallow plasticity layers at high temperatures and a low-ductility grain boundary debonding occurred at 700 °C. The discussion also proposes methods to improve resistance to cracking.

  13. Microwave-Assisted Preparation of High Entropy Alloys

    Directory of Open Access Journals (Sweden)

    Paolo Veronesi

    2015-10-01

    Full Text Available Microwaves at the ISM (Industrial, Scientific and Medical, reserved internationally frequency of 2450 or 5800 MHz have been used to prepare FeCoNiCuAl, FeCrNiTiAl and FeCoCrNiAl2.5 high entropy alloys by direct heating of pressed mixtures of metal powders. The aim of this work is to explore a new microwave-assisted near-net-shape technology, using a powder metallurgy approach for the preparation of high entropy alloys, able to overcome the limits of current melting technologies (defects formation or solid state ones (time demanding. High entropy alloy compositions have been selected so as to comprise at least one ferromagnetic element and one highly reactive couple, like Ni-Al, Ti-Al, Co-Al or Fe-Al. Results show that direct microwave heating of the powder precursors occurs, and further heating generation is favored by the ignition of exothermal reactions in the load. Microwaves have been applied both for the ignition and sustaining of such reactions, showing that by the proposed technique, it is possible to control the cooling rate of the newly-synthesized high entropy alloys. Results showed also that microwave heating in predominant magnetic field regions of the microwave applicator is more effective at controlling the cooling rate. The herein proposed microwave-assisted powder metallurgy approach is suitable to retain the shape of the load imparted during forming by uniaxial pressing. The homogeneity of the prepared high entropy alloys in all cases was good, without the dendritic segregation typical of arc melting, even if some partially-unreacted powders were detected in the samples.

  14. Plasma-assisted catalytic dry reforming of methane: Highly catalytic performance of nickel ferrite nanoparticles embedded in silica

    Science.gov (United States)

    Zheng, Xiaogang; Tan, Shiyu; Dong, Lichun; Li, Shaobo; Chen, Hongmei

    2015-01-01

    Spinel nickel ferrite nanoparticles (NiFe2O4 NPs) embedded in silica (NiFe2O4#SiO2) was prepared to enhance the reaction performance of the dry reforming of methane in a coaxial dielectric barrier discharge reactor. NiFe2O4 NPs of around 10 nm were effectively embedded in porous SiO2 NPs (∼100 nm in diameter). Compared to the supported Ni-based catalysts (Ni/γ-Al2O3, Ni-Fe/γ-Al2O3, Ni-Fe/SiO2, and NiFe2O4), the NiFe2O4#SiO2 catalyst placed at the discharge zone exhibited excellent catalytic performance and high resistance to carbon formation during dry reforming under ambient conditions without the involvement of extra heat. The synergetic effect between the non-thermal plasma and the NiFe2O4#SiO2 catalyst favored the conversion of CH4 and CO2 into syngas. The results indicated that the special structure of the as-synthesized NiFe2O4#SiO2 catalyst was capable of restraining the aggregation of Ni-Fe alloy and suppressing the carbon formation in the reforming process.

  15. In situ Raman spectroscopic analysis of surface oxide films on Ni-base alloy/low alloy steel dissimilar metal weld interfaces in high-temperature water

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jongjin; Choi, Kyung Joon [School of Mechanical and Nuclear Engineering, Ulsan National Institute of Science and Technology (UNIST), 100 Banyeon-ri, Eonyang-eup, Ulju-gun, Ulsan 689-798 (Korea, Republic of); Bahn, Chi Bum [School of Mechanical Engineering, Pusan National University 2, 63-gil, Geumjeong-Gu, Pusan 609-735 (Korea, Republic of); Kim, Ji Hyun, E-mail: kimjh@unist.ac.kr [School of Mechanical and Nuclear Engineering, Ulsan National Institute of Science and Technology (UNIST), 100 Banyeon-ri, Eonyang-eup, Ulju-gun, Ulsan 689-798 (Korea, Republic of)

    2014-06-01

    In situ Raman spectroscopy has been applied to analyze the surface oxide films formed on dissimilar metal weld (DMW) interfaces of nickel-base alloy/low alloy steel under hydrogenated high-temperature water condition. For the analysis of the oxide films under high temperature/pressure aqueous conditions, an in situ Raman spectroscopy system was developed by constructing a hydrothermal cell where the entire optics including the excitation laser and the Raman light collection system were located at the nearest position to the specimen by means of immersion optics. In situ Raman spectra of the DMW interfaces were collected in hydrogenated water condition at different temperatures up to 300 °C. The measured in situ Raman spectra showed peaks of Cr{sub 2}O{sub 3}, NiCr{sub 2}O{sub 4} and Fe{sub 3}O{sub 4} at the DMW interface. It is considered that differences in the oxide chemistry originated from the chemical element distribution inside of the DMW interface region.

  16. The effect of thermal and mechanical cycling on bond strength of a ceramic to nickel-chromium (Ni-Cr) and cobalt-chromium (Co-Cr) alloys.

    Science.gov (United States)

    Vojdani, M; Shaghaghian, S; Khaledi, A; Adibi, S

    2012-01-01

    This study evaluates the effect of thermo-mechanical cycling (TMC) on the bond strength of a ceramic to three cobalt-chromium (Co-Cr) and two nickel-chromium (Ni-Cr) alloys. One hundred metal-ceramic specimens were prepared. While half of the specimens from each metal-ceramic combination (n = 10) were tested after storage in water at 37°C for 24 hours, the other half were subjected to TMC before testing. The bond strength was evaluated by the flexural strength test according to ISO 9693:1999 (E) recommendations. TMC decreased the bond strength of the tested metal-ceramic systems as compared to the water storage (control groups) (P=0.04). Although metal alloys were significantly different from each other in their bond strength with porcelain (P<0.001), the effect of TMC on the various metal-ceramic systems was not significantly different (P=0.99). It may be concluded that base metal-ceramic bond strength is affected by aging and the effect is relatively the same for all the tested porcelain-metal systems.

  17. The Interfacial Microstructure and Mechanical Properties of Diffusion-Bonded Joints of 316L Stainless Steel and the 4J29 Kovar Alloy Using Nickel as an Interlayer

    Directory of Open Access Journals (Sweden)

    Tingfeng Song

    2016-11-01

    Full Text Available 316L stainless steel (Fe–18Cr–11Ni and a Kovar (Fe–29Ni–17Co or 4J29 alloy were diffusion-bonded via vacuum hot-pressing in a temperature range of 850–950 °C with an interval of 50 °C for 120 min and at 900 °C for 180 and 240 min, under a pressure of 34.66 MPa. Interfacial microstructures of diffusion-bonded joints were characterized by optical microscopy (OM, scanning electron microscopy (SEM, X-ray diffraction (XRD, and energy dispersive spectroscopy (EDS. The inter-diffusion of the elements across the diffusion interface was revealed via electron probe microanalysis (EPMA. The mechanical properties of the joints were investigated via micro Vickers hardness and tensile strength. The results show that an Ni interlayer can serve as an effective diffusion barrier for the bonding of 316L stainless steel and the 4J29 Kovar alloy. The composition of the joints was 316L/Ni s.s (Fe–Cr–Ni/remnant Ni/Ni s.s (Fe–Co–Ni/4J29. The highest tensile strength of 504.91 MPa with an elongation of 38.75% was obtained at 900 °C for 240 min. After the width of nickel solid solution (Fe–Co–Ni sufficiently increased, failure located at the 4J29 side and the fracture surface indicated a ductile nature.

  18. Modeling of high entropy alloys of refractory elements

    Energy Technology Data Exchange (ETDEWEB)

    Grosso, M.F. del, E-mail: delgrosso@tandar.cnea.gov.ar [Gcia. Investigacion y Aplicaciones, CNEA, Av. Gral Paz 1499, (B1650KNA), San Martin (Argentina); GCMM, UTN, FRG Pacheco, Av. H. Yrigoyen 288, Gral. Pacheco (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas, CONICET (Argentina); Bozzolo, G. [Loyola University Maryland, 4501 N. Charles St., Baltimore, MD 21210 (United States); Mosca, H.O. [Gcia. Investigacion y Aplicaciones, CNEA, Av. Gral Paz 1499, (B1650KNA), San Martin (Argentina); GCMM, UTN, FRG Pacheco, Av. H. Yrigoyen 288, Gral. Pacheco (Argentina)

    2012-08-15

    Reverting the traditional process of developing new alloys based on one or two single elements with minority additions, the study of high entropy alloys (HEA) (equimolar combinations of many elements) has become a relevant and interesting new field of research due to their tendency to form solid solutions with particular properties in the absence of intermetallic phases. Theoretical or modeling studies at the atomic level on specific HEA, describing the formation, structure, and properties of these alloys are limited due to the large number of constituents involved. In this work we focus on HEA with refractory elements showing atomistic modeling results for W-Nb-Mo-Ta and W-Nb-Mo-Ta-V HEA, for which experimental background exists. An atomistic modeling approach is applied for the determination of the role of each element and identification of the interactions and features responsible for the transition to the high entropy regime. Results for equimolar alloys of 4 and 5 refractory elements, for which experimental results exist, are shown. A straightforward algorithm is introduced to interpret the transition to the high entropy regime.

  19. TEM observation on phase separation and interfaces of laser surface alloyed high-entropy alloy coating.

    Science.gov (United States)

    Cai, Zhaobing; Cui, Xiufang; Jin, Guo; Liu, Zhe; Li, Yang; Dong, Meiling

    2017-12-01

    Phase separation is a common phenomenon in traditional alloys. Under the condition of appropriate undercooling, the segregation phenomenon can be also found in blue-chip high-entropy alloys (HEAs). In this work, the phase separation behavior and interfacial investigation of laser surface alloyed HEA coating with high content Ti were studied principally by transmission electron microscopy. The results show that crystal structure and elementary composition on both sides of the interface of coating/substrate are quite different, and the interfaces between different phases are incoherent or semi-coherent boundarys, resolved by high resolution transmission electron microscopy. In the interface of (Co, Ni)Ti 2 phase/β-Ti phase, there is angle of 80° between BCC〈100〉 and FCC〈201〉. An interesting 'island' structure, that β-Ti phases are embraced by (Co, Ni)Ti 2 compounds in the BCC matrix, was observed definitely, which is attributed to the combined action of Ti segregation and inter-attraction of Ti and other elements. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Wear-dependent specific coefficients in a mechanistic model for turning of nickel-based superalloy with ceramic tools

    Directory of Open Access Journals (Sweden)

    López de Lacalle Luis Norberto

    2017-09-01

    Full Text Available Difficult to cut materials such as nickel and titanium alloys are used in the aeronautical industry, the former alloys due to its heat-resistant behavior and the latter for the low weight - high strength ratio. Ceramic tools made out alumina with reinforce SiC whiskers are a choice in turning for roughing and semifinishing workpiece stages. Wear rate is high in the machining of these alloys, and consequently cutting forces tends to increase along one operation.

  1. Features of formation of the structure in production of blanks of disks of heat-resistant nickel alloys

    Science.gov (United States)

    Vlasova, O. N.; Korneeva, N. N.; Eremenko, V. I.; Fatkullin, O. Kh.; Semenova, N. M.; Petrova, S. N.; Vaulin, D. D.

    1991-12-01

    To provide a high level of mechanical properties in wrought blanks of cast ÉP741NP and ÉP962 alloys it is necessary to form controlled structures. A "necklace"-type structure formed in homogenizing isostatic treatment, subsequent thermomechanical working including alternation of the operations of deformation in the (γ+γ')-area and recrystallization anneals, and final heat treatment is preferable. The temperature conditions of all stages of thermomechanical working are strictly controlled, especially the final operation of deformation and heating for hardening. To eliminate hardening cracks and distortions it is necessary to use molten salts at t=600°C as quenchants. The use of multiple production operations makes it possible to significantly reduce the structural inhomogeneity related to inhertance of the original dendritic structure. However, the structure of the final semifinished product is nevertheless characterized by a difference in occurrence of the processes of polygonization and recrystallization between the former dendritic cells and the interdendritic spaces in deformation and heat treatment. To obtain structurally homogeneous blanks for gas turbine engine parts it is necessary to use basically new methods of remelting such as vacuum double electrode remelting and electron beam remelting with an intermediate vessel.

  2. A novel Nickel-Aluminum alloy with Titanium for improved anode performance and properties in Molten Carbonate Fuel Cells

    Science.gov (United States)

    Frattini, Domenico; Accardo, Grazia; Moreno, Angelo; Yoon, Sung Pil; Han, Jong Hee; Nam, Suk Woo

    2017-06-01

    The anode materials of MCFC require more investigations in order to boost performances at long term. In literature, many NiAl modified alloys have been proposed but not always enhanced cell performance and improved mechanical properties are achieved together. In this work, differently from previous literature, the use of Ti in a NiAl/Ti system is proposed as an effective strategy to enhance both mechanical and electrochemical properties. Results show that bending strength and stiffness increase whereas creep deformation under high pressure-temperature is lower, i.e. around 5-6%, compared to 7.5% of the standard benchmark. The preliminary cell tests carried out show also how the performance, in terms of current and voltage output, is better for anodes with Ti addition with a maximum power density of 165 mW cm-2 at 300 mA cm-2 for Ti 5% compared to 149 mW cm-2 of Ni5Al at the same current density. Finally, the best electrochemical behavior is found for the Ti 5% sample as it achieved the lowest internal and charge transfer resistance at the end of tests. These results suggest that NiAl/Ti systems can be eligible anode materials and are worthy to be investigated more in order to attract a renewed interest for development of MCFCs.

  3. Comparative analysis of the fit of 3-unit implant-supported frameworks cast in nickel-chromium and cobalt-chromium alloys and commercially pure titanium after casting, laser welding, and simulated porcelain firings.

    Science.gov (United States)

    Tiossi, Rodrigo; Rodrigues, Renata Cristina Silveira; de Mattos, Maria da Glória Chiarello; Ribeiro, Ricardo Faria

    2008-01-01

    This study compared the vertical misfit of 3-unit implant-supported nickel-chromium (Ni-Cr) and cobalt-chromium (Co-Cr) alloy and commercially pure titanium (cpTi) frameworks after casting as 1 piece, after sectioning and laser welding, and after simulated porcelain firings. The results on the tightened side showed no statistically significant differences. On the opposite side, statistically significant differences were found for Co-Cr alloy (118.64 microm [SD: 91.48] to 39.90 microm [SD: 27.13]) and cpTi (118.56 microm [51.35] to 27.87 microm [12.71]) when comparing 1-piece to laser-welded frameworks. With both sides tightened, only Co-Cr alloy showed statistically significant differences after laser welding. Ni-Cr alloy showed the lowest misfit values, though the differences were not statistically significantly different. Simulated porcelain firings revealed no significant differences.

  4. Hydrogen Assisted Cracking of High Strength Alloys

    National Research Council Canada - National Science Library

    Gangloff, Richard P

    2003-01-01

    ... (Irwin and Wells, 1997; Paris, 1998). Second, materials scientists developed metals with outstanding balances of high tensile strength and high fracture toughness (Garrison, 1990; Wells, 1993; Boyer, 1993...

  5. Commercialization of NASA's High Strength Cast Aluminum Alloy for High Temperature Applications

    Science.gov (United States)

    Lee, Jonathan A.

    2003-01-01

    In this paper, the commercialization of a new high strength cast aluminum alloy, invented by NASA-Marshall Space Flight Center, for high temperature applications will be presented. Originally developed to meet U.S. automotive legislation requiring low- exhaust emission, the novel NASA aluminum alloy offers dramatic improvement in tensile and fatigue strengths at elevated temperatures (450 F-750 F), which can lead to reducing part weight and cost as well as improving performance for automotive engine applications. It is an ideal low cost material for cast components such as pistons, cylinder heads, cylinder liners, connecting rods, turbo chargers, impellers, actuators, brake calipers and rotors. NASA alloy also offers greater wear resistance, dimensional stability, and lower thermal expansion compared to conventional aluminum alloys, and the new alloy can be produced economically from sand, permanent mold and investment casting. Since 2001, this technology was licensed to several companies for automotive and marine internal combustion engines applications.

  6. Effect of residual elements on high performance nickel base ...

    Indian Academy of Sciences (India)

    Unknown

    The need for better gas turbine operating efficiency and reliability has resulted in tightening of specification and acceptance standards ... added in controlled amounts to enhance the hot workability or high temperature performance. .... tion, tundish design and type of filter etc in order to pro- duce premium quality superalloys.

  7. Coin exposure may cause allergic nickel dermatitis: a review.

    Science.gov (United States)

    Thyssen, Jacob P; Gawkrodger, David J; White, Ian R; Julander, Anneli; Menné, Torkil; Lidén, Carola

    2013-01-01

    Nickel is used in coins because the metal has beneficial properties, including price, colour, weight, and corrosion resistance, and also because it is easy to stamp. It has often been claimed that the duration of skin contact with coins is too short to cause nickel release and dermatitis. However, it is well known by dermatologists specialized in occupational skin diseases, and by their nickel-allergic patients, that hand eczema in cashiers and other professionals who handle coins may be caused or aggravated by nickel release from coins. In this review, we present evidence from past studies showing that nickel-containing coins can indeed pose a risk for those who handle them. For protection of the health of consumers, cashiers, and other workers who handle coins, it is suggested that coins without nickel release should be used as a substitute for the high nickel-releasing coins currently in widespread use. The key risk factor in this situation is the ability of metal alloys in coins to release nickel and contaminate the skin after repeated contact from coin handling. © 2012 John Wiley & Sons A/S.

  8. First-principles prediction of high-entropy-alloy stability

    Science.gov (United States)

    Feng, Rui; Liaw, Peter K.; Gao, Michael C.; Widom, Michael

    2017-11-01

    High entropy alloys (HEAs) are multicomponent compounds whose high configurational entropy allows them to solidify into a single phase, with a simple crystal lattice structure. Some HEAs exhibit desirable properties, such as high specific strength, ductility, and corrosion resistance, while challenging the scientist to make confident predictions in the face of multiple competing phases. We demonstrate phase stability in the multicomponent alloy system of Cr-Mo-Nb-V, for which some of its binary subsystems are subject to phase separation and complex intermetallic-phase formation. Our first-principles calculation of free energy predicts that the configurational entropy stabilizes a single body-centered cubic (BCC) phase from T = 1700 K up to melting, while precipitation of a complex intermetallic is favored at lower temperatures. We form the compound experimentally and confirm that it develops as a single BCC phase from the melt, but that it transforms reversibly at lower temperatures.

  9. One-step synthesis of nitrogen-doped carbon nanofibers from melamine over nickel alloy in a closed system

    Science.gov (United States)

    Kenzhin, Roman M.; Bauman, Yuri I.; Volodin, Alexander M.; Mishakov, Ilya V.; Vedyagin, Aleksey A.

    2017-10-01

    A novel approach to the synthesis of nitrogen-doped carbon nanofibers in a closed system at elevated pressure with the use of bulk Ni-Cr alloy as a catalyst precursor was proposed. Melamine was chosen as a substrate containing both carbon and nitrogen. Method of ferromagnetic resonance was applied for diagnostics of dispersed Ni particles appearance. The process of corrosion of a bulk alloy followed by formation of dispersed Ni particles catalyzing the growth of nitrogen-doped carbon nanofibers was found to take place at temperatures above 560 °C. The final content of nitrogen in obtained carbon nanofibers was about 10 at.%.

  10. Application of powder metallurgy to an advanced-temperature nickel-base alloy, NASA-TRW 6-A

    Science.gov (United States)

    Freche, J. C.; Ashbrook, R. L.; Waters, W. J.

    1971-01-01

    Bar stock of the NASA-TRW 6-A alloy was made by prealloyed powder techniques and its properties evaluated over a range of temperatures. Room temperature ultimate tensile strength was 1894 MN/sq m (274 500 psi). The as-extruded powder product showed substantial improvements in strength over the cast alloy up to 649 C (1200 F) and superplasticity at 1093 C (2000 F). Both conventional and autoclave heat treatments were applied to the extruded powder product. The conventional heat treatment was effective in increasing rupture life at 649 and 704 C (1200 and 1300 F); the autoclave heat treatment, at 760 and 816 C (1400 and 1500 F).

  11. INFLUENCE OF HIGH SPEED OF CRYSTALLIZATION ON THE STRUCTURE OF ALUMINIUM ALLOYS

    Directory of Open Access Journals (Sweden)

    G. V. Dovnar

    2010-01-01

    Full Text Available The aim of the work is development of new compositions of aluminium alloys with refractory metals of transition group and cremnium due to range extension of alloying at usage of high speed of melts cooling.

  12. Damage and service life of nickel-base alloys under thermal-mechanical fatigue stress at different phase positions; Schaedigung und Lebensdauer von Nickelbasislegierungen unter thermisch-mechanischer Ermuedungsbeanspruchung bei verschiedenen Phasenlagen

    Energy Technology Data Exchange (ETDEWEB)

    Guth, Stefan

    2016-07-01

    This work considers the behaviour of two nickel-base alloys (NiCr22Co12Mo9 and MAR-M247 LC) under thermo-mechanical fatigue loading with varying phase angles between mechanical strain and temperature. The investigations focus on the characterisation of microstructures and damage mechanisms as a function of the phase angle. Based on the results, a life prediction model is proposed.

  13. Advanced Corrosion-Resistant Zr Alloys for High Burnup and Generation IV Application

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Y. H.; Park, S. Y.; Lee, M. H.; Choi, B. K.; Baek, J. H.; Park, J. Y.; Kim, J. H.; Kim, H. G.; Jung, Y. H.; Bang, B. G

    2006-08-15

    The systematic study was performed to develop the advanced corrosion-resistant Zr alloys for high burnup and Gen IV application. The corrosion behavior was significantly changed with the alloy composition and the corrosion environment. In general, the model alloys with a higher alloying elements showed a higher corrosion resistance. Among the model alloys tested in this study, Zr-10Cr-0.2Fe showed the best corrosion resistance regardless of the corrosion condition. The oxide on the higher corrosion-resistant alloy such as Zr-1.0Cr-0.2Fe consisted of mainly columnar grains, and it have a higher tetragonal phase stability. In comparison with other alloys being considered for the SCWR, the Zr alloys showed a lower corrosion rate than ferritic-martensitic steels. The results of this study imply that, at least from a corrosion standpoint, Zr alloys deserve consideration as potential cladding or structural materials in supercritical water cooled reactors.

  14. Effect of Nb Doping on High Temperature Oxidation Resistance of Ti-Al Alloyed Coatings

    Directory of Open Access Journals (Sweden)

    DAI Jing-jie

    2017-02-01

    Full Text Available Ti-Al alloyed coatings with different Nb doping contents were fabricated on TC4 titanium alloy by laser surface alloying to improve high temperature oxidation resistance of the alloy. Structures and high temperature oxidation behaviors of the alloyed coatings were analyzed and tested by X-ray diffraction (XRD, scanning electron microscope (SEM, energy dispersive spectrometer (EDS and box-type resistance furnace. The results show that the alloyed coatings consist of TiAl and Ti3Al, and no niobium compound are formed in Ti-Al-Nb alloyed coatings. The alloyed coatings are uniform and exhibit excellent metallurgical bonding with the substrates. A large amount of surface cracks and a few penetrating cracks are formed in Ti-Al alloyed coating without Nb doping, while no obvious cracks are formed in Ti-Al alloyed coating with Nb doping. The oxidation mass gains of all the alloyed coatings were significantly lower than those of the substrate. The alloyed coatings with Nb doping exhibit more excellent high temperature oxidation resistance due to the beneficial machanism of Nb doping. The mechanism of Nb doping on improving high temperature oxidation resistance of Ti-Al alloyed coatings includes reducing the defect concentration of TiO2, refining oxide grains and promoting the formation of Al2O3.

  15. Effect of alloying additions on structure and mechanical properties of high carbon Fe-16 wt.% Al alloy

    Energy Technology Data Exchange (ETDEWEB)

    Baligidad, R.G.; Radhakrishna, A. [Defence Metallurgical Research Lab., Hyderabad (India)

    2000-07-15

    Effect of quaternary alloying elements Mn,Cr,Ni and Ti on structure and properties of Fe{sub 3}Al-based alloy containing about l wt.% carbon have been investigated. Four different alloys were prepared. The composition of the quaternary alloying element was proposed to be {approx}4 wt.% and was substituted for iron. Processing of Fe-16Al-4.1Mn-1.0C,Fe-16.5Al-3.5Cr-0.94C,Fe-16Al-4.0Ni-0.9C and Fe-15.6Al-2.8Ti-1.0C alloys through a combination of air induction melting with flux cover (AIM) and electroslag remelting (ESR) yields a sound ingot free from macro and microporosity with very low sulphur, oxygen and nitrogen. This process route also exhibited excellent recovery of alloying elements. As-cast alloys were examined using optical microscopy, X-ray diffraction, electron probe microanalyses (EPMA) and scanning electron microscopy (SEM) in conjunction with energy dispersive X-ray analysis to understand the microstructure of these alloys. The as-cast ESR ingots of alloys containing Mn, Cr and Ni exhibited a two-phase structure of Fe{sub 3}AlC{sub 0.5} precipitate in the Fe{sub 3}Al-based matrix. Both phases exhibited considerable amount of solid solubility for Mn, Cr and Ni, whereas the alloy containing Ti exhibited a three-phase microstructure of TiC particles and Fe{sub 3}AlC precipitates in the Fe{sub 3}Al-based matrix. This alloy has also exhibited very low solubility of Ti in the Fe{sub 3}Al-based matrix and no solubility in the Fe{sub 3}AlC precipitates. Several microcracks were observed in the as-cast ESR ingots of the high carbon Fe{sub 3}Al alloy containing Ni and tensile tests could not be carried out for this composition. Tensile and creep tests were performed on the high carbon Fe{sub 3}Al alloys containing Mn, Cr and Ti in the as-cast condition. No improvement in room temperature tensile strength and inferior high temperature strength and creep properties was observed by the addition of quaternary alloying elements. (orig.)

  16. Zirconium alloys with small amounts of iron and copper or nickel show improved corrosion resistance in superheated steam

    Science.gov (United States)

    Greenberg, S.; Youngdahl, C. A.

    1967-01-01

    Heat treating various compositions of zirconium alloys improve their corrosion resistance to superheated steam at temperatures higher than 500 degrees C. This increases their potential as fuel cladding for superheated-steam nuclear-fueled reactors as well as in autoclaves operating at modest pressures.

  17. Surface Modification and Alloying of Aluminum and Titanium Alloys with Low-Energy, High-Current Electron Beams

    Directory of Open Access Journals (Sweden)

    V. P. Rotshtein

    2011-01-01

    Full Text Available The paper reviews the results of investigations of surface modification and alloying of Al, Ti, and its alloys with a low-energy (up to ~40 keV, high-current (up to 25 J/cm2 electron beams of microsecond duration under systematically varied conditions. The microstructural evolution of the surface layers of Al alloys (Al2024 and Al6061 and Ti-6Al-4V alloy subjected to pulsed melting as well as changes in surface-sensitive properties of these alloys are considered. Phase formation and properties of Al-based and Ti-based surface alloys, synthesized by liquid-phase mixing of multilayer film-substrate systems in wide range of solid solubility, including [Al/Si]/Al, [Al/C]/Al, [Zr/Ti]/Ti-6Al-4V, and Al/Ti, are studied. In case of Ti-based substrates, this method allows to fabricate the single-phase nanocrystalline α-(TiZr surface alloy, free of Al and V, as well as nanosized and ultrafine grain TiAl/Ti3Al-based surface alloys of thickness ≥3 μm with enhanced mechanical properties.

  18. Refractory High-Entropy Alloys (Preprint)

    Science.gov (United States)

    2011-07-01

    the equimolar mixtures of the corresponding elements. High purity titanium was used as a getter for residual gases in the high vacuum chamber. The...tungsten, molybdenum and vanadium were in the form of 45.7 mm diameter rods with a purity of 99.7%, 99.0% and 99.9%, respectively. The tantalum and...15.6 9.08 / 21.0 Table 2. The crystal lattice parameter, a, density, ρ, and Vickers hardness, Hv, of high purity W, Nb, Mo, Ta and V metals, and

  19. Evaluation of nickel-rich alloys for the electrolytic generation of hydrogen in an alkaline medium; Evaluacion de aleaciones ricas en niquel para la generacion electrolitica de hidrogeno en medio alcalino

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz Verdin, A.A.; Ortega Borges, R.; Trejo Cordova, G.; Meas Vong, Y. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, S.C., Pedro Escobedo, Queretaro (Mexico)]. E-mail: aortiz@cideteq.mx

    2009-09-15

    The simultaneous electrodeposition of Ni with metals such as Zn to form alloys enables obtaining surfaces with high electrocatalytic activity or particular characteristics that resist wear and abrasion. This work presents the results of the study of the electrochemical characterization of different types of nickel electrodeposition and compositions, used as cathodes, and measurements of the electrocatalytic activity in the release of hydrogen in an alkaline medium. Curves I through IV were generated, which were potentiostatically obtained in a nitrogen atmosphere in a NaOH alkaline solution. The morphology of the deposits was evaluated with sweep electron micrscopy(SEM). The results enabled evaluating its potential application as electrode materials for the generation of electrolytic hydrogen in alkaline medium, given the good electrocatalytic activity of nickel-rich materials. [Spanish] El electrodeposito simultaneo del Ni, con metales como el Zn para formar aleaciones, permite obtener superficies con elevada actividad electrocatalitica o con caracteristicas particulares de resistencia al desgaste y abrasion. En este trabajo se presentan los resultados del estudio de la caracterizacion electroquimica de los electrodepositos a base de niquel de diferente naturaleza y composicion utilizandolos como catodos midiendo la actividad electrocatalitica con respecto a la reaccion de desprendimiento de hidrogeno (RDH) en medio alcalino. Se realizaron curvas I vs V obtenidas potenciostaticamente bajo atmosfera de nitrogeno en una solucion alcalina de NaOH. La morfologia de los depositos se evaluo mediante SEM (microscopio electronico de barrido). Los resultados permiten evaluar su potencial aplicacion como materiales de electrodo para la generacion electrolitica de hidrogeno en medio alcalino, dada la buena actividad electrocatalitica de los materiales ricos en niquel.

  20. High-speed deformation processing of a titanium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Tamirisakandala, S.; Medeiros, S.C.; Malas, J.C. [Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson Air Force Base, OH 45433 (United States); Yellapregada, P.V.R.K. [Department of Metallurgy, Indian Institute of Science Bangalore, Karnataka 560 012 (India); Frazier, W.G. [NCPA Coliseum Drive, University, MS 38677 (United States); Dutta, B. [Department of Materials Science, Darmstadt University of Technology, Petersenstrasse 23, D-64287 Darmstadt (Germany)

    2003-09-01

    The deformation rate is the critical parameter for the phase transforming mechanism and subsequently the morphology of Ti-Al-V alloys, which in turn determines the feasibility of high-speed deformation. The evolution of defect-free equiaxed microstructures is due to dislocation-induced heterogeneous nucleation and growth. The Figure shows a microstructure of a Ti-6Al-4V specimen deformed at 1000 C in a backscattered SEM image. (Abstract Copyright [2003], Wiley Periodicals, Inc.)