WorldWideScience

Sample records for alloy systems

  1. Hydrogen storage systems from waste Mg alloys

    Science.gov (United States)

    Pistidda, C.; Bergemann, N.; Wurr, J.; Rzeszutek, A.; Møller, K. T.; Hansen, B. R. S.; Garroni, S.; Horstmann, C.; Milanese, C.; Girella, A.; Metz, O.; Taube, K.; Jensen, T. R.; Thomas, D.; Liermann, H. P.; Klassen, T.; Dornheim, M.

    2014-12-01

    The production cost of materials for hydrogen storage is one of the major issues to be addressed in order to consider them suitable for large scale applications. In the last decades several authors reported on the hydrogen sorption properties of Mg and Mg-based systems. In this work magnesium industrial wastes of AZ91 alloy and Mg-10 wt.% Gd alloy are used for the production of hydrogen storage materials. The hydrogen sorption properties of the alloys were investigated by means of volumetric technique, in situ synchrotron radiation powder X-ray diffraction (SR-PXD) and calorimetric methods. The measured reversible hydrogen storage capacity for the alloys AZ91 and Mg-10 wt.% Gd are 4.2 and 5.8 wt.%, respectively. For the Mg-10 wt.% Gd alloy, the hydrogenated product was also successfully used as starting reactant for the synthesis of Mg(NH2)2 and as MgH2 substitute in the Reactive Hydride Composite (RHC) 2LiBH4 + MgH2. The results of this work demonstrate the concrete possibility to use Mg alloy wastes for hydrogen storage purposes.

  2. Ti-V-Mn based alloys for hydrogen compression system

    Energy Technology Data Exchange (ETDEWEB)

    Dehouche, Z. [Institut de Recherche sur l' hydrogene, Universite du Quebec a Trois-Rivieres, C.P. 500, Trois-Rivieres, Que., G9A 5H7 (Canada)]. E-mail: zahir_dehouche@uqtr.ca; Savard, M. [Institut de Recherche sur l' hydrogene, Universite du Quebec a Trois-Rivieres, C.P. 500, Trois-Rivieres, Que., G9A 5H7 (Canada); Laurencelle, F. [Institut de Recherche sur l' hydrogene, Universite du Quebec a Trois-Rivieres, C.P. 500, Trois-Rivieres, Que., G9A 5H7 (Canada); Goyette, J. [Institut de Recherche sur l' hydrogene, Universite du Quebec a Trois-Rivieres, C.P. 500, Trois-Rivieres, Que., G9A 5H7 (Canada)

    2005-09-01

    Ti-V-Mn based hydrides are one family of alloys with improved hydrogenation properties and they have a great potential to replace the AB{sub 5} alloys as the sorption materials in hydrogen compression systems, although there still are many problems associated with their use, including unstable reversible hydrogen capacity and unfavorable thermodynamic properties. To gain a better understanding on the effect of the substitution elements and to optimize the alloy composition for high storage capacity, the influence of the alloy stoichiometry was investigated. Ti-Zr-V-Mn alloys were prepared by arc melting technique and were annealed in vacuum at temperature above 900 deg. C to obtain great sorption properties. Hydrogen absorption and desorption kinetics and PCT characteristics of these alloys at ambient temperature were measured and compared. These hydrogen storage features were also discussed in relation to the effect of alloy element compositions. Ti-Zr-V-Mn alloy cycling behavior was also examined.

  3. Ti-V-Mn based alloys for hydrogen compression system

    International Nuclear Information System (INIS)

    Ti-V-Mn based hydrides are one family of alloys with improved hydrogenation properties and they have a great potential to replace the AB5 alloys as the sorption materials in hydrogen compression systems, although there still are many problems associated with their use, including unstable reversible hydrogen capacity and unfavorable thermodynamic properties. To gain a better understanding on the effect of the substitution elements and to optimize the alloy composition for high storage capacity, the influence of the alloy stoichiometry was investigated. Ti-Zr-V-Mn alloys were prepared by arc melting technique and were annealed in vacuum at temperature above 900 deg. C to obtain great sorption properties. Hydrogen absorption and desorption kinetics and PCT characteristics of these alloys at ambient temperature were measured and compared. These hydrogen storage features were also discussed in relation to the effect of alloy element compositions. Ti-Zr-V-Mn alloy cycling behavior was also examined

  4. Mechanical alloying in the Fe-Cu system

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Gente, C.; Bormann, R.

    The studies of mechanical alloying on the Fe-Cu system, as a model system for those with positive heats of mixing, are reviewed. Several problems involved in the mechanical alloying process are discussed. For example, (1) whether alloying occurs on an atomic level; (2) what the solid solubility in...... the Fe-Cu system is; (3) where the positive energy is stored in the alloys; (4) what the decomposition process of the supersaturated alloys is; and (5) what type of magnetic properties the new materials have. The elucidation of these problems will shed light on the understanding of the mechanisms for...... the preparation of materials under highly non-equilibrium conditions in systems with positive heats of mixing by mechanical alloying....

  5. Developing of an expert system for nonferrous alloy design

    Institute of Scientific and Technical Information of China (English)

    李义兵; 何红波; 周继承; 李斌

    2004-01-01

    Expert systems have been used widely in the predictions and design of alloy systems. But the expert systems are based on the macroscopic models that have no physical meanings. Microscopic molecular dynamics is also a standard computational technique used in materials science. An approach is presented to the design system of nonferrous alloy that integrates the molecular dynamical simulation together with an expert system. The knowledge base in the expert system is able to predict nonferrous alloy properties by using machine learning technology. The architecture of the system is presented.

  6. Structural alloys for superconducting magnets in fusion energy systems

    International Nuclear Information System (INIS)

    The behaviour of selected alloys for superconducting magnet structures in fusion energy systems is reviewed with emphasis on the following austenitic stainless steels (AISI grades 304, 310S and 316), nitrogen-strengthened austenitic stainless steels (types 304LN, 316LN and 21Cr-6Ni-9Mn) and aluminium alloys (grades 5083, 6061 and 2219). The mechanical and physical properties of the selected alloys at 4 K are reviewed. Welding, the properties of weldments, and other fabrication considerations are briefly discussed. The available information suggests that several commercial alloys have adequate properties at 4 K and sufficient fabrication characteristics for the large magnet structures needed for fusion energy systems. (orig.)

  7. Structural alloys for superconducting magnets in fusion energy systems

    International Nuclear Information System (INIS)

    The behavior of selected alloys for superconducting magnet structures in fusion energy systems is reviewed with emphasis on austenitic stainless steels (AISI grades 304, 310S, and 316), nitrogen-strengthened austenitic stainless steels (304LN, 316LN, and 21Cr-6Ni-9Mn) and aluminum alloys (5083, 6061, and 2219). The mechanical and physical properties of the selected alloys at 40K are reviewed. Welding, properties of weldments, and other fabrication considerations are briefly discussed. The available information suggests that several commercial alloys have adequate properties at 40K and sufficient fabrication characteristics for the large magnet structures needed for fusion energy systems

  8. Single-, two-, and three-phase binary-alloy systems

    Science.gov (United States)

    Tenney, D. R.

    1980-01-01

    Series of three computer programs solves one-dimensional transient diffusion problems in single-and multiphase binary-alloy systems. Accurate understanding of diffusion process in binary-alloy system is important for development of metal matrix composites, some protective coatings, and thin-film technology.

  9. Alloys oxidation of aluminium-scandium system

    International Nuclear Information System (INIS)

    Alloys and compounds of rare earth metals with aluminium thanks to their high corrosion stability, durability and small specific weight find to apply in various new techniques. On the base of carried out investigation it could be recommend as de oxidizing and alloying compositions containing 15-50 % of scandium as in possession of minimal oxidation

  10. Aluminum Alloying Effects on Lattice Types, Microstructures, and Mechanical Behavior of High-Entropy Alloys Systems

    Science.gov (United States)

    Tang, Zhi; Gao, Michael C.; Diao, Haoyan; Yang, Tengfei; Liu, Junpeng; Zuo, Tingting; Zhang, Yong; Lu, Zhaoping; Cheng, Yongqiang; Zhang, Yanwen; Dahmen, Karin A.; Liaw, Peter K.; Egami, Takeshi

    2013-12-01

    The crystal lattice type is one of the dominant factors for controlling the mechanical behavior of high-entropy alloys (HEAs). For example, the yield strength at room temperature varies from 300 MPa for the face-centered-cubic (fcc) structured alloys, such as the CoCrCuFeNiTi x system, to about 3,000 MPa for the body-centered-cubic (bcc) structured alloys, such as the AlCoCrFeNiTi x system. The values of Vickers hardness range from 100 to 900, depending on lattice types and microstructures. As in conventional alloys with one or two principal elements, the addition of minor alloying elements to HEAs can further alter their mechanical properties, such as strength, plasticity, hardness, etc. Excessive alloying may even result in the change of lattice types of HEAs. In this report, we first review alloying effects on lattice types and properties of HEAs in five Al-containing HEA systems: Al x CoCrCuFeNi, Al x CoCrFeNi, Al x CrFe1.5MnNi0.5, Al x CoCrFeNiTi, and Al x CrCuFeNi2. It is found that Al acts as a strong bcc stabilizer, and its addition enhances the strength of the alloy at the cost of reduced ductility. The origins of such effects are then qualitatively discussed from the viewpoints of lattice-strain energies and electronic bonds. Quantification of the interaction between Al and 3 d transition metals in fcc, bcc, and intermetallic compounds is illustrated in the thermodynamic modeling using the CALculation of PHAse Diagram method.

  11. Corrosion of copper alloys in sulphide containing district heting systems

    DEFF Research Database (Denmark)

    Thorarinsdottir, R.I.; Maahn, Ernst Emanuel

    1999-01-01

    Copper and some copper alloys are prone to corrosion in sulphide containing geothermal water analogous to corrosion observed in district heating systems containing sulphide due to sulphate reducing bacteria. In order to study the corrosion of copper alloys under practical conditions a test was...... carried out at four sites in the Reykjavik District Heating System. The geothermal water chemistry is different at each site. The corrosion rate and the amount and chemical composition of deposits on weight loss coupons of six different copper alloys are described after exposure of 12 and 18 months...

  12. Overlay metallic-cermet alloy coating systems

    Science.gov (United States)

    Gedwill, M. A.; Levine, S. R.; Glasgow, T. K. (Inventor)

    1984-01-01

    A substrate, such as a turbine blade, vane, or the like, which is subjected to high temperature use is coated with a base coating of an oxide dispersed, metallic alloy (cermet). A top coating of an oxidation, hot corrosion, erosion resistant alloy of nickel, cobalt, or iron is then deposited on the base coating. A heat treatment is used to improve the bonding. The base coating serves as an inhibitor to interdiffusion between the protective top coating and the substrate. Otherwise, the protective top coating would rapidly interact detrimentally with the substrate and degrade by spalling of the protective oxides formed on the outer surface at elevated temperatures.

  13. System for ultra high vacuum made of aluminum alloys

    International Nuclear Information System (INIS)

    We have developed the system for ultra high vacuum made of aluminum alloys for proton and electron synchrotron. This is the first system for ultra high vacuum in which bakable metal seal flange and small diametral bellows of aluminum alloys have been put to practical use. The system consists of the flange protected by a CrN thin film and made of 2219-T87 alloy, the chamber made of 6063-T6 alloy, the aluminum metal gasket of Helico Flex and the bellows made of 5052 alloy. As a result of experiments at the National Laboratory for High Energy Physics (KEK), it had been confirmed that this system shows the special qualities of ultra high vacuum operation, resistance to hard radiation and baking and cooling operations. Up to now, this system has been widely used for the beam lines of the booster synchrotron utilization facility, K1, K2, linac, PI 1 and EP2-B extension of the KEK proton synchrotron. We investigate that this system is applicable to nuclear energy utilization facility and general vacuum apparatus. (author)

  14. Random alloy diffusion kinetics for the application to multicomponent alloy systems

    Science.gov (United States)

    Paul, T. R.; Belova, I. V.; Murch, G. E.

    2016-04-01

    In this paper, extensive Monte Carlo simulation results are reported on tracer and collective diffusion correlation effects in the random ternary alloy, as an example of a multicomponent alloy system. The problem of analytically describing both collective and tracer diffusion kinetics is also addressed for the random multicomponent alloy by application of a combination of the Manning theory and Holdsworth and Elliott theory. It is found that the overall results from the combined theory agree reasonably well with Monte Carlo results. This combined approach is much more accurate than Manning's approach itself and much more manageable than the almost exact, but unfortunately difficult to use, self-consistent theory of Moleko, Allnatt and Allnatt. Some relations between the Onsager phenomenological coefficients and tracer diffusion coefficients are derived and are tested with our Monte Carlo data. Good agreement is found.

  15. Low Temperature Shape Memory Alloys for Adaptive, Autonomous Systems Project

    Science.gov (United States)

    Falker, John; Zeitlin, Nancy; Williams, Martha; Benafan, Othmane; Fesmire, James

    2015-01-01

    The objective of this joint activity between Kennedy Space Center (KSC) and Glenn Research Center (GRC) is to develop and evaluate the applicability of 2-way SMAs in proof-of-concept, low-temperature adaptive autonomous systems. As part of this low technology readiness (TRL) activity, we will develop and train low-temperature novel, 2-way shape memory alloys (SMAs) with actuation temperatures ranging from 0 C to 150 C. These experimental alloys will also be preliminary tested to evaluate their performance parameters and transformation (actuation) temperatures in low- temperature or cryogenic adaptive proof-of-concept systems. The challenge will be in the development, design, and training of the alloys for 2-way actuation at those temperatures.

  16. Creep properties of Zr-based alloys with Zr-xNb-xSn-Fe-Cr-Mn alloying system

    International Nuclear Information System (INIS)

    To investigate the effect of Nb and Sn on the mechanical properties of Zr-based alloys with Zr-xNb-xSn-Fe-Cr-Mn alloying system, the Zr-based alloys were manufactured as two kinds of sheet specimens and tested for tensile properties and creep behaviors. PK2 alloy, which have more Sn content than Nb, showed higher tensile strength and creep resistance than PK1 alloy. With rising the applied stress and test temperature, PK1 and PK2 alloys increased the steady state creep rate and activation energy for the creep of the alloys. This behavior would be due to the effect of solid-solution hardening of Sn and the dislocation in worked structure. The stress exponent of the alloys also increased in response to rise the applied stress at the constant temperature. In the stress range of 50 to 180 MPa at 350 .deg. C and 400 .deg. C, the alloys showed creep deformation behavior due to diffusion and viscous dislocation glide mechanism below 4 of the stress exponent (n). Based on the higher stress exponent than 7. It is thought that the alloys were strained by dislocation climb mechanism at the applied stress over 100 MPa at 450 .deg. C

  17. Solid state amorphisation in binary systems prepared by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, G., E-mail: gemagonz@ivic.v [Lab. Ciencia e Ing. de Materiales, Instituto Venezolano de Investigaciones Cientificas, IVIC, Caracas (Venezuela, Bolivarian Republic of); Sagarzazu, A. [Lab. Ciencia e Ing. de Materiales, Instituto Venezolano de Investigaciones Cientificas, IVIC, Caracas (Venezuela, Bolivarian Republic of); Bonyuet, D. [Instituto de Investigacion en Biomedicina y Ciencias Aplicadas, Universidad de Oriente, Cumana (Venezuela, Bolivarian Republic of); D' Angelo, L. [UNEXPO, Universidad Experimental Politecnica Luis Caballero Mejias, Dpto. Ing. Mecanica (Venezuela, Bolivarian Republic of); Villalba, R. [Lab. Ciencia e Ing. de Materiales, Instituto Venezolano de Investigaciones Cientificas, IVIC, Caracas (Venezuela, Bolivarian Republic of)

    2009-08-26

    In the present work a detailed study of amorphisation in different systems prepared by mechanical alloying under the same experimental conditions was carried out, milling up to 50 and 100 h in some cases. The systems studied were: AlTi, AlNi, AlFe, FeNi, FeCo, NiMo, NiW, NiCo, MoW, CoMo. These systems were chosen to study the effect of Al-transition metal, transition metal-transition metal and also systems with large and small negative heat of mixing, different and similar crystal structures, atomic sizes and diffusion coefficients. Calculations based on the Miedema model for alloy formation and amorphisation on all the alloys studied were performed. The experimental results from X-ray diffraction and transmission electron microscopy showed that the systems based on Fe (FeNi, FeCo and FeAl) did not amorphised, even after milling for 100 h, and formed a stable solid solution with a nanometric grain size of 7 nm. The systems NiMo, NiW, MoW and CoMo (systems with small negative heat of mixing), showed amorphisation after 50 h of milling. NiAl and TiAl form an intermediate amorphous phase after around 20 h of milling and with further milling they recrystallize into a fcc solid solution. Agreement between the theoretical calculations based on the Miedema model and the experimental results was found in most of the systems.

  18. Solid state amorphisation in binary systems prepared by mechanical alloying

    International Nuclear Information System (INIS)

    In the present work a detailed study of amorphisation in different systems prepared by mechanical alloying under the same experimental conditions was carried out, milling up to 50 and 100 h in some cases. The systems studied were: AlTi, AlNi, AlFe, FeNi, FeCo, NiMo, NiW, NiCo, MoW, CoMo. These systems were chosen to study the effect of Al-transition metal, transition metal-transition metal and also systems with large and small negative heat of mixing, different and similar crystal structures, atomic sizes and diffusion coefficients. Calculations based on the Miedema model for alloy formation and amorphisation on all the alloys studied were performed. The experimental results from X-ray diffraction and transmission electron microscopy showed that the systems based on Fe (FeNi, FeCo and FeAl) did not amorphised, even after milling for 100 h, and formed a stable solid solution with a nanometric grain size of 7 nm. The systems NiMo, NiW, MoW and CoMo (systems with small negative heat of mixing), showed amorphisation after 50 h of milling. NiAl and TiAl form an intermediate amorphous phase after around 20 h of milling and with further milling they recrystallize into a fcc solid solution. Agreement between the theoretical calculations based on the Miedema model and the experimental results was found in most of the systems.

  19. Scandium Binary and Ternary Alloy Systems and Intermetallic Compounds

    OpenAIRE

    Kotur, Bogdan Ya.

    1998-01-01

    Scandium is the first d-element and a member of the rare earths family. The available data, published until the beginning of 1997, on scandium binary and ternary alloy systems and intermetallic compounds with other elements (with the exception of halogens, hydrogen, oxygen, sulphur and nitrogen) have been reviewed. Data about 65 binary and about 200 ternary systems have been generalized. The crystal chemical analysis of 462 investigated intermetallic compounds (out of 554 known to date) belon...

  20. An Electromotive Force Measurement System for Alloy Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Changhu Xing; Colby Jensen; Heng Ban; Robert Mariani; J. Rory Kennedy

    2010-11-01

    The development of advanced nuclear fuels requires a better understanding of the transmutation and micro-structural evolution of the materials. Alloy fuels have the advantage of high thermal conductivity and improved characteristics in fuel-cladding chemical reaction. However, information on thermodynamic and thermophysical properties is limited. The objective of this project is to design and build an experimental system to measure the thermodynamic properties of solid materials from which the understanding of their phase change can be determined. The apparatus was used to measure the electromotive force (EMF) of several materials in order to calibrate and test the system. The EMF of chromel was measured from 100°C to 800°C and compared with theoretical values. Additionally, the EMF measurement of Ni-Fe alloy was performed and compared with the Ni-Fe phase diagram. The prototype system is to be modified eventually and used in a radioactive hot-cell in the future.

  1. Experimental analyses of dynamical systems involving shape memory alloys

    DEFF Research Database (Denmark)

    Enemark, Søren; Savi, Marcelo A.; Santos, Ilmar F.

    2015-01-01

    The use of shape memory alloys (SMAs) in dynamical systems has an increasing importance in engineering especially due to their capacity to provide vibration reductions. In this regard, experimental tests are essential in order to show all potentialities of this kind of systems. In this work, SMA...... springs. This article shows several experimental tests that allow one to obtain a general comprehension of the dynamical behaviour of SMA systems. Results show the general thermo-mechanical behaviour of SMA dynamical systems and the obtained conclusions can be applied in distinct situations as in rotor...

  2. Phase equilibria in alloys of Cr-Hf-N system

    International Nuclear Information System (INIS)

    Metallographic, X-ray phase and differential thermal analyses are used to study phase equilibria in alloys of the Cr-Hf-N system with nitrogen concentration less than 15% (at.). Isothermal section at 1150 deg C is plotted. The polythermal Cr-HfN section is stated to be quasibinary eutectic one. Maximal solubility of HfN in chromium is estimated by thermodynamic calculation

  3. The copper-nickel alloy system for dental applications mechanical properties

    International Nuclear Information System (INIS)

    Four types of alloys were investigated to determine the feasibility of developing a non-noble casting alloy based on the copper-nickel system. Emphasis was given to the evaluation of its mechanical properties, which included tensile properties and hardness. Tensile properties included yield strength, ultimate tensife strength, modulus of elasticity and ductility, As demonstrated in this study, thefouralfoys, with the exception of alloy4, possessed mechanical properties of intermediate values between those of gold and base-metal alloys. (author)

  4. Shape memory alloys applied to improve rotor-bearing system dynamics - an experimental investigation

    OpenAIRE

    Enemark, Søren; Santos, Ilmar; Marcelo A. Savi

    2015-01-01

    tor-bearing systems have critical speeds and to pass through them is an ongoing challenge in the field of mechanical engineering. The incorporation of shape memory alloys in rotating systems has an increasing importance to improve system performance and to avoid potential damaging situations when passing through critical speeds. In this work, the feasibility of applying shape memory alloys to a rotating system is experimentally investigated. Shape memory alloys can change their stiffness with...

  5. System and method of forming nanostructured ferritic alloy

    Energy Technology Data Exchange (ETDEWEB)

    Dial, Laura Cerully; DiDomizio, Richard; Alinger, Matthew Joseph; Huang, Shenyan

    2016-07-26

    A system for mechanical milling and a method of mechanical milling are disclosed. The system includes a container, a feedstock, and milling media. The container encloses a processing volume. The feedstock and the milling media are disposed in the processing volume of the container. The feedstock includes metal or alloy powder and a ceramic compound. The feedstock is mechanically milled in the processing volume using metallic milling media that includes a surface portion that has a carbon content less than about 0.4 weight percent.

  6. Polyphase alloys as rechargeable electrodes in advanced battery systems

    Science.gov (United States)

    Huggins, Robert A.

    1987-01-01

    The rechargeability of electrochemical cells is often limited by negative electrode problems. These may include loss of capacity, increased impedance, macroscopic shape change, dendrite growth, or a tendency for filamentary or whisker growth. In principle, these problems can be reduced or eliminated by the use of alloys that undergo either displacement or insertion reactions at reactant species activities less than unity, rather than pure elements. The fundamental reasons for some of these problems with elemental electrodes, as well as the basic principles involved in the different behavior of alloys, are briefly discussed. More information is now available concerning the thermodynamic and kinetic properties of a number of alloys of potential interest for use as electrodes in elevated temperature lithium battery systems. Recent results have extended these results down to ambient temperatures, indicating that some such materials may be of interest for use with new low temperature molten salt electrolytes, or with organic solvent electrolytes. The all solid mixed conductor matrix concept is also reviewed.

  7. Thermodynamic potential of electrons and phonons system of disordered alloy

    International Nuclear Information System (INIS)

    The cluster decomposition for the delayed two-time Green functions and the disordered crystal dynamic potential is obtained with an account of the electron-phonon and electron-electron interactions. The system electron states are described within the frames of the multizone strong coupling model. The calculations are based on the diagram technique for the Green temperature functions. The coherent potential approximation is chosen as the zero mononode approximation in this cluster decomposition method. It is shown that the processes of the contributions of the elementary excitations scattering on the clusters decrease with the cluster nodes number growth in the cluster in correspondence with certain small parameters. The analytical evaluations of the electron-phonon interaction impact on the electron energy spectrum of the ordering alloy are made in the monozone model. The possibility of applying the obtained results for describing the strong electron correlations impact on the electron structure and properties for the transition metal alloys with narrow energy zones is shown by the Fe-Ti alloy example

  8. Microstructural investigation of uranium rich U–Zr–Nb ternary alloy system

    Energy Technology Data Exchange (ETDEWEB)

    Ghoshal, Kaushik, E-mail: kghoshal@barc.gov.in; Kaity, Santu; Mishra, Sudhir; Kumar, Arun

    2014-03-15

    Uranium rich U–Zr–Nb alloy system is a potential candidate among the family of alloys considered as metallic fuel for fast reactors application. As a part of the program U–7% Zr, U–5% Zr–2% Nb, U–3.5% Zr–3.5% Nb, U–2% Zr–5% Nb and U–7% Nb (composition in wt.%) alloys were prepared. The total amount of Nb and Zr was restricted, because higher addition of non-fissile alloying element not only reduces the fissile content it also decreases the breeding ratio due to parasitic absorption. The alloys were characterized by SEM micrograph. The phase analysis was performed with the help of XRD and the phase transformation temperatures were determined by DTA. The variation in crystal structure with subsequent replacement of Zr with Nb as an alloying element has been highlighted. The as quenched U–7% Nb alloy shows complete γ° phase at ambient temperature.

  9. Refractory metal alloys and composites for space power systems

    International Nuclear Information System (INIS)

    Space power requirements for future NASA and other United States missions will range from a few kilowatts to megawatts of electricity. Maximum efficiency is a key goal of any power system in order to minimize weight and size so that the space shuttle may be used a minimum number of times to put the power supply into orbit. Nuclear power has been identified as the primary power source to meet these high levels of electrical demand. One method to achieve maximum efficiency is to operate the power supply, energy conversion system, and related components at relatively high temperatures. NASA Lewis Research Center has undertaken a research program on advanced technology of refractory metal alloys and composites that will provide base line information for space power systems in the 1900's and the 21st century. Basic research on the tensile and creep properties of fibers, matrices, and composites will be discussed

  10. ASSET, An Information System for Alloy Corrosion in High Temperature Gases

    International Nuclear Information System (INIS)

    A large database for corrosion data and a corrosion prediction information system for metals and alloys corroding in high-temperature gases have been created. Corrosion data for about 75 commercial alloys, 4600 corrosion data measurements, and six million exposure hours have been compiled into an information system, ASSET. ASSET allows prediction of sound metal thickness losses for metals and alloys corroding by several common corrosion mechanisms at high-temperatures as functions of gas composition, temperature, time, and alloy. This paper presents examples of predicted metal losses of alloys corroding in standard conditions for several corrosion mechanisms expected in high-temperature gases. ASSET also provides a comprehensive capability to analyze the thermochemical interactions between alloys, corrosion products and exposure conditions. Some of the uses of the data compilation and the corrosion prediction feature are illustrated for oxidizing, sulfidizing, sulfidizing/oxidizing , and carburizing conditions

  11. Application Of Shape Memory Alloy In Harvesto-Absorber System

    Directory of Open Access Journals (Sweden)

    Kęcik Krzysztof

    2015-09-01

    Full Text Available This paper presents a conception of the harvester-absorber system consisting of two parts. The first is the pendulum attached to the main system (oscillator, which is suspended on the linear damper and the nonlinear spring made of shape memory alloy. The spring is modelled as a polynomial function based on Landau–Ginzburg theory of phase transitions (similar as ferroelectric and ferromagnets. The obtained results show, that SMA element can increase harvesting energy level, while the absorber effect can be impaired (but not loss. Additionally, introducing SMA element causes changes in dynamics, introduces a new unstable solutions and bifurcations. The analysis was done by classical integration and continuation solution methods.

  12. Novel tribological systems using shape memory alloys and thin films

    Science.gov (United States)

    Zhang, Yijun

    Shape memory alloys and thin films are shown to have robust indentation-induced shape memory and superelastic effects. Loading conditions that are similar to indentations are very common in tribological systems. Therefore novel tribological systems that have better wear resistance and stronger coating to substrate adhesion can be engineered using indentation-induced shape memory and superelastic effects. By incorporating superelastic NiTi thin films as interlayers between chromium nitride (CrN) and diamond-like carbon (DLC) hard coatings and aluminum substrates, it is shown that the superelasticity can improve tribological performance and increase interfacial adhesion. The NiTi interlayers were sputter deposited onto 6061 T6 aluminum and M2 steel substrates. CrN and DLC coatings were deposited by unbalanced magnetron sputter deposition. Temperature scanning X-ray diffraction and nanoindentation were used to characterize NiTi interlayers. Temperature scanning wear and scratch tests showed that superelastic NiTi interlayers improved tribological performance on aluminum substrates significantly. The two-way shape memory effect under contact loading conditions is demonstrated for the first time, which could be used to make novel tribological systems. Spherical indents in NiTi shape memory alloys and thin films had reversible depth changes that were driven by temperature cycling, after thermomechanical cycling, or one-cycle slip-plasticity deformation training. Reversible surface topography was realized after the indents were planarized. Micro- and nano- scale circular surface protrusions arose from planarized spherical indents in bulk and thin film NiTi alloy; line surface protrusions appeared from planarized scratch tracks. Functional surfaces with reversible surface topography can potentially result in novel tribological systems with reversible friction coefficient. A three dimensional constitutive model was developed to describe shape memory effects with slip

  13. Shape-Memory-Alloy-Based Deicing System Developed

    Science.gov (United States)

    1996-01-01

    Ice buildup on aircraft leading edge surfaces has historically been a problem. Most conventional deicing systems rely either on surface heating to melt the accreted ice or pneumatic surface inflation to mechanically debond the ice. Deicers that rely solely on surface heating require large amounts of power. Pneumatic deicers usually cannot remove thin layers of ice and lack durability. Thus, there is a need for an advanced, low-power ice protection system. As part of the NASA Small Business and Innovation Research (SBIR) program, Innovative Dynamics, Inc., developed an aircraft deicing system that utilizes the properties of Shape Memory Alloys (SMA). The SMA-based system has achieved promising improvements in energy efficiency and durability over more conventional deicers. When they are thermally activated, SMA materials change shape; this is analogous to a conventional thermal expansion. The thermal input is currently applied via conventional technology, but there are plans to implement a passive thermal input that is supplied from the energy transfer due to the formation of the ice itself. The actively powered deicer was tested in the NASA Lewis Icing Research Tunnel on a powered rotating rig in early 1995. The system showed promise, deicing both rime and glaze ice shapes as thin as 1/8 in. The first prototype SMA deicer reduced power usage by 45 percent over existing electrothermal systems. This prototype system was targeted for rotorcraft system development. However, there are current plans underway to develop a fixed-wing version of the deicer.

  14. Replacement of Co-base alloy for radiation exposure reduction in the primary system of PWR

    International Nuclear Information System (INIS)

    Of numerous Co-free alloys developed to replace Co-base stellite used in valve hardfacing material, two iron-base alloys of Armacor M and Tristelle 5183 and one nickel-base alloy of Nucalloy 488 were selected as candidate Co-free alloys, and Stellite 6 was also selected as a standard hardfacing material. These four alloys were welded on 316SS substrate using TIG welding method. The first corrosion test loop of KAERI simulating the water chemistry and operation condition of the primary system of PWR was designed and fabricated. Corrosion behaviors of the above four kinds of alloys were evaluated using this test loop under the condition of 300 deg C, 1500 psi. Microstructures of weldment of these alloys were observed to identify both matrix and secondary phase in each weldment. Hardnesses of weld deposit layer including HAZ and substrate were measured using micro-Vickers hardness tester. The status on the technology of Co-base alloy replacement in valve components was reviewed with respect to the classification of valves to be replaced, the development of Co-free alloys, the application of Co-free alloys and its experiences in foreign NPPs, and the Co reduction program in domestic NPPs and industries. 18 tabs., 20 figs., 22 refs. (Author)

  15. Recent developments of the aluminium-lithium system alloys for aircraft uses

    International Nuclear Information System (INIS)

    A brief review is made of the latest developments in the production of Aluminium-Lithium alloys. The necessity for new materials in the field of aeronautics has speeded up research on metallic and non-metallic materials. Lately, a good part of the research in the field of metallic components has been directed at Al-Li alloys. More recently, with the development of quaternary alloys Al-Li-X-X, the old problem of low toughness was overcome. The finality of this study is to cover the developments of the mentioned alloys, including the fundamentals of physical metallurgy of the complex system recently developed Al-Li-Cu-Mg. (author)

  16. Thermodynamic potential of electrons and phonons system of disordered alloy

    CERN Document Server

    Repetskij, S P

    2002-01-01

    The cluster decomposition for the delayed two-time Green functions and the disordered crystal dynamic potential is obtained with an account of the electron-phonon and electron-electron interactions. The system electron states are described within the frames of the multizone strong coupling model. The calculations are based on the diagram technique for the Green temperature functions. The coherent potential approximation is chosen as the zero mononode approximation in this cluster decomposition method. It is shown that the processes of the contributions of the elementary excitations scattering on the clusters decrease with the cluster nodes number growth in the cluster in correspondence with certain small parameters. The analytical evaluations of the electron-phonon interaction impact on the electron energy spectrum of the ordering alloy are made in the monozone model. The possibility of applying the obtained results for describing the strong electron correlations impact on the electron structure and propertie...

  17. Generator cooling hydrogen purity improvement system using hydrogen absorbing alloy; Suiso kyuzo gokin riyo hatsudenkinai suiso jundo kojo system

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, H.; Kabutomori, T.; Wakisaka, Y. [Japan Steel Works, Ltd., Tokyo (Japan); Nishimura, Y.; Kogi, T.; Sato, J.; Haruki, N. [Kansai Electric Power Co. Inc., Osaka (Japan); Fujita, T. [Mitsubishi Electric Corp., Tokyo (Japan)

    1998-09-15

    Described herein is a system which uses a hydrogen-absorbing alloy to purify a hydrogen gas stream used as a coolant for power generator. Hydrogen in the stream containing impurities such as nitrogen can be selectively absorbed by sufficiently cooled hydrogen-absorbing alloy. Impurity gases concentrated in the alloy pores are released, and then the alloy is heated to release hydrogen. This purifies hydrogen to at least 99.99%. This system essentially consists of an hydrogen-absorbing unit, hot water production/supply system which circulates hot water of 80 to 90degC to release hydrogen out of the alloy, pretreatment unit, and temperature and pressure sensors. It is confirmed, by the test in which the system is connected to a commercial power generator of 600MW, that the system can be continuously operated to purify hydrogen to at least 99.9% for an extended period. 4 refs., 18 figs., 1 tab.

  18. A comparison of thermoelectric phenomena in diverse alloy systems

    Energy Technology Data Exchange (ETDEWEB)

    Cook, Bruce

    1999-01-01

    The study of thermoelectric phenomena in solids provides a wealth of opportunity for exploration of the complex interrelationships between structure, processing, and properties of materials. As thermoelectricity implies some type of coupled thermal and electrical behavior, it is expected that a basic understanding of transport behavior in materials is the goal of such a study. However, transport properties such as electrical resistivity and thermal diffusivity cannot be fully understood and interpreted without first developing an understanding of the material's preparation and its underlying structure. It is the objective of this dissertation to critically examine a number of diverse systems in order to develop a broad perspective on how structure-processing-property relationships differ from system to system, and to discover the common parameters upon which any good thermoelectric material is based. The alloy systems examined in this work include silicon-germanium, zinc oxide, complex intermetallic compounds such as the half-Heusler MNiSn, where M = Ti, Zr, or Hf, and rare earth chalcogenides.

  19. A study of surface tension driven segregation in monotectic alloy systems

    Science.gov (United States)

    Andrews, J. Barry; Andrews, Rosalia N.; Gowens, Terrell F.

    1988-01-01

    The compatibilities of various monotectic alloy systems with several different crucible materials were evaluated. The study was carried out using small candidate alloy samples of compositions that produced fifty volume percent of each liquid phase at the monotectic temperature. Compatibility was based on the evaluation of the wetting tendency of the two immiscible phases with the crucible material in a one-g solidified sample. Three types of wetting phenomena were observed during the evaluation. Type 1 indicates an alloy-crucible combination where the L2 phase preferentially wets the crucible material. Since L2 is usually the minority phase in desirable alloys, this material combination would be difficult to process and is therefore considered incompatible. Type 2 behavior indicates an alloy-crucible combination where the L1 phase preferentially wets the crucible material. This type of combination is considered compatible since surface tension effects should aid in processing the alloy to a useful form. Type 3 indicates any combination that leads to major reactions between the alloy and crucible material, gas entrapment, or separation of the metal from the crucible wall. Additional compatibility evaluations would have to be carried out on combinations of this category. The five alloy systems studied included aluminum-bismuth, copper-lead, aluminum-indium, aluminum-lead and cadmium-gallium. The systems were combined with crucibles of alumina, boron nitride, mullite, quartz, silicon carbide and zirconia.

  20. Corrosion of alloys of the niobium--titanium--aluminium system

    International Nuclear Information System (INIS)

    The mechanical properties and corrosion resistance of niobium--titanium--aluminum alloys in 20 percent HCl and 40--75 percent H2SO4 at 40 and 1000C are considered. Current density vs potential and corrosion rate vs potential potentiostatic curves plotted in 75 percent H2SO4 at 1400C for the alloys with different titanium contents at a constant content of aluminum and also for alloys with a constant titanium content at different contents of aluminum are given. It was shown that the corrosion resistance of the alloys in 75 percent H2SO4 at 1400C is an exponential function of the atomic content of the alloying components (Ti, Al) in them; aluminum vitiates the corrosion resistance very strongly

  1. Investigation of austenitic alloys for advanced heat recovery and hot gas cleanup systems

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, R.W.; Ren, W. [Oak Ridge National Lab., TN (United States)

    1995-08-01

    Alloys for design and construction of structural components needed to contain process streams and provide internal structures in advanced heat recovery and hot gas cleanup systems were examined. Emphasis was placed on high-strength, corrosion-resistant alloys for service at temperatures above 1000 {degrees}F (540{degrees}C). Data were collected that related to fabrication, joining, corrosion protection, and failure criteria. Alloys systems include modified type 310 and 20Cr-25Ni-Nb steels and sulfidation-resistance alloys HR120 and HR160. Types of testing include creep, stress-rupture, creep crack growth, fatigue, and post-exposure short-time tensile. Because of the interest in relatively inexpensive alloys for high temperature service, a modified type 310 stainless steel was developed with a target strength of twice that for standard type 310 stainless steel.

  2. Investigation of austenitic alloys for advanced heat recovery and hot gas cleanup systems

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, R.W.; Ren, W. [Oak Ridge National Lab., TN (United States)

    1996-08-01

    Materials properties were collected for the design and construction of structural components for use in advanced heat recovery and hot gas cleanup systems. Alloys systems included 9Cr-1Mo-V steel, modified 316 stainless steel, modified type 310 stainless steel, modified 20Cr-25Ni-Nb stainless steel, modified alloy 800, and two sulfidation resistant alloys: HR160 and HR120. Experimental work was undertaken to expand the databases for potentially useful alloys. Types of testing included creep, stress-rupture, creep-crack growth, fatigue, and post-exposure short-time tensile tests. Because of the interest in relatively inexpensive alloys for service at 700{degrees}C and higher, research emphasis was placed on a modified type 310 stainless steel and a modified 20Cr-25Ni-Nb stainless steel. Both steels were found to have useful strength to 925{degrees}C with good weldability and ductility.

  3. Nonlinear Analysis of Shape Memory Alloy Component in Rotor System

    Institute of Scientific and Technical Information of China (English)

    王洪礼; 赵涛; 竺致文

    2004-01-01

    The active control of rotor vibration was studied while shape memory alloy (SMA) spring component was chosen as bearing of rotor system. The vibration of rotor system was controlled by the phase transformation of SMA with electric heating method. The SMA spring component has nonlinear coupling problem of thermal stress and thermal elasticity,because thermal constants α,β and elasticity constants λ,G vary with temperature when temperature changes sharply. Because δ,ε were both small parameters, their square items could be ignored and approximate results were obtained by perturbation. The characters of α,β,λ,G changing with temperature were analyzed. Results show that the character of thermal diffusivity α changes with temperature, which cannot influence U,Ψ,So the nonlinearity of α can be ignored; the character of β changes with temperature, which cannot influence U, but influences Ψ at high temperature; the character of λ,G change with temperature, which cannot influence Ψ, but influences U with U(01)ε. The more λ,G, the more their influence on U; the nonlinearity of (βT)/(ρcv)εkk influences U and Ψ, which must be calculated.

  4. New alloying systems for ferrous powder metallurgy precision parts

    Directory of Open Access Journals (Sweden)

    Danninger H.

    2008-01-01

    Full Text Available Traditionally, the common alloy elements for sintered steels have been Cu and Ni. With increasing requirements towards mechanical properties, and also as a consequence of soaring prices especially for these two metals, other alloy elements have also become more and more attractive for sintered steels, which make the steels however more tricky to process through PM. Here, the chances and risks of using in particular Cr and Mn alloy steels are discussed, considering the different alloying techniques viable in powder metallurgy, and it is shown that there are specific requirements in particular for sintering process. The critical importance of chemical reactions between the metal and the atmosphere is described, and it is shown that not only O2 and H2O but also H2 and even N2 can critically affect sintering and microstructural homogenization.

  5. Nonlinear dynamics of a pseudoelastic shape memory alloy system - theory and experiment

    DEFF Research Database (Denmark)

    Enemark, Søren; A Savi, M.; Santos, Ilmar

    2014-01-01

    In this work, a helical spring made from a pseudoelastic shape memory alloy was embedded in a dynamic system also composed of a mass, a linear spring and an excitation system. The mechanical behaviour of shape memory alloys is highly complex, involving hysteresis, which leads to damping capabilit......In this work, a helical spring made from a pseudoelastic shape memory alloy was embedded in a dynamic system also composed of a mass, a linear spring and an excitation system. The mechanical behaviour of shape memory alloys is highly complex, involving hysteresis, which leads to damping...... capabilities and varying stiffness. Besides, these properties depend on the temperature and pretension conditions. Because of these capabilities, shape memory alloys are interesting in relation to engineering design of dynamic systems. A theoretical model based on a modification of the 1D Brinson model was...... and forced vibrations of the system setup under different temperature conditions. The experiments give a thorough insight into dynamic systems involving pseudoelastic shape memory alloys. Comparison between experimental results and the proposed model shows that the model is able to explain and predict...

  6. The shape memory effect in systems Cu-based alloys

    OpenAIRE

    2013-01-01

    330a The aim of this work was to analyse the mechanisms of hindered internal passivation of silver based alloys which was obtained by the modification of basic chemical composition. A generalisation of the phenomenon, experimental verification and the estimated range of micro-element concentration is also introduced. The ability for inoculation of a particular alloy is determined by the differences between the formation energies of oxides, as well as their crystallographic similarity. Therefo...

  7. Structural, mechanical and electrical properties of alloys in ternary Ag-Bi-Zn system

    Energy Technology Data Exchange (ETDEWEB)

    Minic, D. M.; Premovic, M. M.; Zivkovic, D. T.; Manasijevic, D. M.; Dimie, M. Z.; Petrovic, Z. R.; Markovic, S. M.

    2015-07-01

    Structural, mechanical and electrical properties of selected alloys in ternary Ag-Bi-Zn system are presented in this paper. Chosen alloys were investigated using X-Ray Diffraction (XRD), light optical microscopy, Scanning Electron Microscopy combined with Energy Dispersive Spectrometry (SEM-EDS), as well as by electrical conductivity and Brinell hardness measurements. Isolines of electrical conductivity and hardness for the entire Ag-Bi-Zn system were calculated using regression models. (Author)

  8. Arc welding of high strength aluminium alloys for armour systems applications

    OpenAIRE

    Pickin, Craig Graeme

    2011-01-01

    The ternary Al-Cu-Mg system 2xxx series aluminium alloys were examined as construction materials for armour system applications based upon comparable ballistic properties to the currently employed Al-7xxx series alloys. Utilising MIG welding solidification cracking was evident when welding constrained Al-2024 candidate base material using Al-2319 filler, the only available consumable wire for this series. A previously developed thermodynamic model suggested that an incompatible...

  9. Study of the titanium alloys surfaces used in orthopaedic systems

    International Nuclear Information System (INIS)

    Total hip prosthesis (THP) is a highly successful orthopaedic device. However, its durability is generally limited to a few decades due to difficult conditions in the human body and huge demands it is subjected to. A hip prosthesis is deteriorating due to high surface pressures caused by mechanical movements of the body. The aim of this project is to improve the characteristics of hip prostheses, in order to increase their functionality and their life span. This paper presents an analysis regarding the topography and tribological parameters of femoral heads structures and of femoral heads coated with TiN. We studied the tribological properties of the surfaces of some femoral heads made of Ti alloys or coated with TiN. These femoral heads were obtained from some prostheses after revision surgery. Afterwards, we used TiN nanostructured coatings for reducing the wear process. TiN thin films were deposited using physical vapour deposition (PVD) and some scratch tests have been realized on these coatings surfaces. The study of coatings surfaces was made using atomic force microscopy (AFM) that offers the possibility to obtain nanometric 3D control of thin films. Main result of these researches is that used coatings offer the possibility to improve the system properties. (authors)

  10. Magnetic properties of X-Pt (X=Fe,Co,Ni) alloy systems

    OpenAIRE

    Paudyal, Durga; Saha-Dasgupta, Tanusri; Mookerjee, Abhijit

    2003-01-01

    We have studied the electronic and magnetic properties of Fe-Pt, Co-Pt and Ni-Pt alloy systems in ordered and disordered phases. The influence of various exchange-correlation functionals on values of equilibrium lattice parameters and magnetic moments in ordered Fe-Pt, Co-Pt and Ni-Pt alloys have been studied using linearized muffin-tin orbital method. The electronic structure calculations for the disordered alloys have been carried out using augmented space recursion technique in the framewo...

  11. Intermetallic eutectic alloys in the Ni-Al-Zr system with attractive high temperature properties

    Directory of Open Access Journals (Sweden)

    Tiwary Chandrasekhar

    2014-01-01

    Full Text Available We describe a group of alloys with ultrahigh strength of about 2 GPa at 700°C and exceptional oxidation resistance to 1100°C. These alloys exploit intermetallic phases with stable oxide forming elements that combine to form fine nanometric scale structures through eutectic transformations in ternary systems. The alloys offer engineering tensile plasticity of about 4% at room temperature though both conventional dislocation mechanisms and twinning in the more complex intermetallic constituent, along with slip lengths that are restricted by the interphase boundaries in the eutectics.

  12. Systems and Methods for the Electrodeposition of a Nickel-cobalt Alloy

    Science.gov (United States)

    Ogozalek, Nance Jo (Inventor); Wistrand, Richard E. (Inventor)

    2013-01-01

    Systems and methods for electrodepositing a nickel-cobalt alloy using a rotating cylinder electrode assembly with a plating surface and an electrical contact. The assembly is placed within a plating bath and rotated while running a plating cycle. Nickel-cobalt alloy deposition is selectively controlled by controlling current density distribution and/or cobalt content in the plating bath while running the plating cycle to deposit an alloy of a desired yield strength onto the plating surface in a single plating cycle. In various embodiments, the rotating cylinder may be used as an insitu monitoring method to assist in obtaining the properties desired.

  13. Design study of fuel circulating system using Pd-alloy membrane isotope separation method

    International Nuclear Information System (INIS)

    Design study on the fuel circulating system (FCS) for a tokamak experimental fusion reactor (JXFR) has been carried out to establish the system concept, to plan the development program, and to evaluate the feasibility of diffusion system. The FCS consists of main vacuum system, fuel gas refiners, isotope separators, fuel feeders, and auxiliary systems. In the system design, Pd-alloy membrane permeation method is adopted for fuel refining and isotope separating. All impurities are effectively removed and hydrogen isotopes are sufficiently separated by Pd-alloy membrane. The isotope separation system consists of 1st (47 separators) and 2nd (46 separators) cascades for removing protium and separating deuterium, respectively. In the FCS, while cryogenic distillation method appears to be practicable, Pd-alloy membrane diffusion method is attractive for isotope separation and refining of fuel gas. The choice will have to be based on reliability, economic, and safety analyses

  14. Investigation of austenitic alloys for advanced heat recovery and hot-gas cleanup systems

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, R.W. [Oak Ridge National Lab., TN (United States)

    1997-12-01

    Materials properties were collected for the design and construction of structural components for use in advanced heat recovery and hot gas cleanup systems. Alloys systems included 9Cr-1Mo-V steel, modified 316 stainless steel, modified type 310 stainless steel, modified 20Cr-25Ni-Nb stainless steel, and modified alloy 800. Experimental work was undertaken to expand the databases for potentially useful alloys. Types of testing included creep, stress-rupture, creep-crack growth, fatigue, and post-exposure short-time tensile tests. Because of the interest in relatively inexpensive alloys for service at 700 C and higher, research emphasis was placed on a modified type 310 stainless steel and a modified 20Cr-25Ni-Nb stainless steel. Both steels were found to have useful strength to 925 C with good weldability and ductility.

  15. New bulk glassy alloys in Cu-Zr-Ag ternary system prepared by casting and milling

    International Nuclear Information System (INIS)

    The thermal stability, crystallization behaviour and glass forming ability of Cu-Zr-Ag system have been investigated on the basis of a ternary phase diagram. We altered the concentration of the alloys from the Cu58Zr42 to the concentration of the deep eutectic point of the Cu-Zr-Ag ternary system and we calculated the glass forming ability parameters. This paper summarises the results of the procedure during which Cu-Zr-Ag amorphous alloys with different Ag content (0-25%) were prepared by casting and ball-milling. Wedge-shaped samples were prepared from the ingots by centrifugal casting into copper mold. The supercooled liquid region (ΔTx) exceeded 75K. Following the characterization of the cast alloys, master alloys of identical composition were milled in a Fritsch Pulverisette 2 ball-mill. The powders, milled for various periods of time were analysed by XRD in order to define the amorphous fraction.

  16. Estimating the Eutectic Composition of Simple Binary Alloy System Using Linear Geometry

    Directory of Open Access Journals (Sweden)

    Muhammed Olawale Hakeem AMUDA

    2008-06-01

    Full Text Available A simple linear equation was developed and applied to a hypothetical binary equilibrium diagram to evaluate the eutectic composition of the binary alloy system. Solution of the equations revealed that the eutectic composition of the case study Pb – Sn, Bi – Cd and Al – Si alloys are 39.89% Pb, 60.11% Sn, 58.01% Bi, 41.99% Cd and 90.94% Al, 9.06% Si respectively. These values are very close to experimental values. The percent deviation of analytical values from experimental values ranged between 2.87 and 5% for the three binary systems considered, except for Si – Al alloy in which the percent deviation for the silicon element was 22%.It is concluded that equation of straight line could be used to predict the eutectic composition of simple binary alloys within tolerable experimental deviation range of 2.5%.

  17. Crystallization behavior and magnetic properties in High Fe content FeBCSiCu alloy system

    International Nuclear Information System (INIS)

    High Fe content FeBCSiCu nanocrystalline alloys are prepared by annealing melt-spun amorphous ribbons with aim at increasing saturation magnetic flux density. Microstructures identified by XRD and TEM reveal that Cu addition inhibits the surface crystallization of Fe86B7C7 alloy and improve its glass-forming ability. Activation energy of crystallization calculated by Kissinger's equation indicates that both Cu and Si addition promotes the precipitation of α-Fe phase and improves the thermal stability. VSM and DC B–H loop tracer measurements show that the Fe85.5B7C6Si1Cu0.5 nanocrystalline alloy exhibits high saturation magnetic flux density of 1.8 T and low coercivity of 10 A/m, respectively. AC properties measured by AC B–H analyzer show this alloy exhibits low core loss of 0.35 W/kg at 1 T at 50 Hz. Low material cost and convenient productivity make the Fe85.5B7C6Si1Cu0.5 nanocrystalline alloy an economical application in industry. - Highlights: • Cu addition inhibits the surface crystallization and improves the GFA. • The competitive formation of Fe3C and α-Fe phase impedes the devitrification. • Fe85.5B7C6Si1Cu0.5 nanocrystalline alloy exhibits excellent magnetic properties. • The alloy system has an economical advantage and convenient productivity

  18. High-temperature shape memory alloys based on the RuNb system

    International Nuclear Information System (INIS)

    Many applications of shape memory alloys (SMAs) require the development of alloys with high martensitic transformation (MT) temperatures. Among the different systems for high temperature SMAs, equiatomic RuNb alloys demonstrate both shape memory effect (SME) and MT temperatures above 800 deg. C. This work investigates Ru50-xNb50+x (at.%) alloys and shows that Nb content significantly affects the MT behavior. Alloys near the equiatomic composition (x = 0, 2, 4) undergo two displacive transformations on cooling: β (B2) → β' (body centered tetragonal) → β'' (monoclinic). The Ru45Nb55 alloy exhibits a single transition from cubic to tetragonal on cooling. This MT gives rise to a highly twinned microstructure with a (0 1 1) compound-twinning mode and is considered to be responsible for the SME in both types of alloys. The reorientation of martensite variants during deformation has been confirmed through scanning electron microscopy of compression specimens. A promising shape memory behavior is obtained through three-point bend tests performed both in the β' and β'' phases

  19. Coating with overlay metallic-cermet alloy systems

    Science.gov (United States)

    Gedwill, M. A.; Levine, S. R.; Glasgow, T. K. (Inventor)

    1984-01-01

    A base layer of an oxide dispersed, metallic alloy (cermet) is arc plasma sprayed onto a substrate, such as a turbine blade, vane, or the like, which is subjected to high temperature use. A top layer of an oxidation, hot corrosion, erosion resistant alloy of nickel, cobalt, or iron is then arc plasma sprayed onto the base layer. A heat treatment is used to improve the bonding. The base layer serves as an inhibitor to interdiffusion between the protective top layer and the substrate. Otherwise, the 10 protective top layer would rapidly interact detrimentally with the substrate and degrade by spalling of the protective oxides formed on the outer surface at elevated temperatures.

  20. The dissolution and formation enthalpy of alloys and intermetallics of aluminium-lanthanum and aluminium-cerium systems

    International Nuclear Information System (INIS)

    Present article is devoted to dissolution and formation enthalpy of alloys and intermetallics of aluminium-lanthanum and aluminium-cerium systems. Therefore the dissolution temperatures of alloys and intermetallics of aluminium-lanthanum and aluminium-cerium systems were defined by means of calorimetry method. The enthalpy of formation of intermetallics of Al-Ce system was defined as well. The regularities in changes of dissolution and formation enthalpy of alloys and intermetallics depending on composition were studied.

  1. Design study of fuel circulating system using Pd alloy membrane isotope separation method

    International Nuclear Information System (INIS)

    It is expected that the method of permeating through Pd-alloy membrances is effective for isotope separation and the refining of fuel gas. In this paper, the design study of the Fuel Circulating System (FCS) using Pb-alloy membranes is described. The study is mainly focused on the main vacuum, fuel gas refining, isotope separating, and tritium containment systems. In the fuel gas refining system, impurities are effectively removed by using Pd-alloy membranes. For the isotope separation system, the diffusion method through Pd-alloy membranes was adopted. From the standpoint of the safety and economy, a three-stage tritium containment system was adopted to control tritium release to the environment as low as possible. The principal conclusion drawn from the design study was as follows. In the FCS, while cryogenic distillation method appears to be practicable, Pd-alloy membrane method is attractive for isotope separation and the refining of fuel gas. For a large amount of tritium inventory, handling and control technologies should be completed by the experimental evaluation and development of the components and materials used for the FCS. A three-stage containment system was adopted to control tritium release to environment as low as possible. Consideration to prevent tritium escape will be necessary for fuel gas refiners and isotope separators. (Kato, T.)

  2. New all aluminum alloy ultrahigh vacuum system and fittings

    International Nuclear Information System (INIS)

    The Al-ICF ALFLAT FLANGE corresponds to the ordinary stainless steel Conflat flange. The Al-ICF ALFLAT FLANGE is made of special aluminum alloy 2219-T87 by forging. It has the highest strength at elevated high temperature among all aluminum alloys as well as superior weldability and stress corrosion cracking resistivity. CrN or TiC coating on the flange surface by ion plating. The CrN or TiC treatment on the surface gave nearly protection against sticking between the knife edge of the flange and the aluminum gasket and surface scratching. Sealing surface of the knife edge for the Helicoflex is finished to a smooth mirror surface by a diamond tool. (author)

  3. Investigation of Effects of Neutron Irradiation on Tantalum Alloys for Radioisotope Power System Applications

    International Nuclear Information System (INIS)

    Tantalum alloys have been used by the U.S. Department of Energy as structural alloys for space nuclear power systems such as Radioisotopic Thermoelectric Generators (RTG) since the 1960s. Tantalum alloys are attractive for high temperature structural applications due to their high melting point, excellent formability, good thermal conductivity, good ductility (even at low temperatures), corrosion resistance, and weldability. A number of tantalum alloys have been developed over the years to increase high-temperature strength (Ta-10%W) and to reduce creep strain (T-111). These tantalum alloys have demonstrated sufficient high-temperature toughness to survive the increasing high pressures of the RTG's operating environment resulting from the alpha decay of the 238-plutonium dioxide fuel. However, 238-plutonium is also a powerful neutron source. Therefore, the RTG operating environment produces large amounts of 3-helium and neutron displacement damage over the 30 year life of the RTG. The literature to date shows that there has been very little work focused on the mechanical properties of irradiated tantalum and tantalum alloys and none at the fluence levels associated with a RTG operating environment. The minimum, reactor related, work that has been reported shows that these alloys tend to follow trends seen in the behavior of other BCC alloys under irradiation. An understanding of these mechanisms is important for the confident extrapolation of mechanical-property trends to the higher doses and gas levels corresponding to actual service lifetimes. When comparing the radiation effects between samples of Ta-10%W and T-111 (Ta-8%W-2%Hf) subjected to identical neutron fluences and environmental conditions at temperatures <0.3Tm (∼700 deg. C), evidence suggests the possibility that T-111 will exhibit higher levels of internal damage accumulation and degradation of mechanical properties compared to Ta-10%W

  4. Investigation of Effects of Neutron Irradiation on Tantalum Alloys for Radioisotope Power System Applications

    Science.gov (United States)

    Barklay, Chadwick D.; Kramer, Daniel P.; Talnagi, Joseph

    2007-01-01

    Tantalum alloys have been used by the U.S. Department of Energy as structural alloys for space nuclear power systems such as Radioisotopic Thermoelectric Generators (RTG) since the 1960s. Tantalum alloys are attractive for high temperature structural applications due to their high melting point, excellent formability, good thermal conductivity, good ductility (even at low temperatures), corrosion resistance, and weldability. A number of tantalum alloys have been developed over the years to increase high-temperature strength (Ta-10%W) and to reduce creep strain (T-111). These tantalum alloys have demonstrated sufficient high-temperature toughness to survive the increasing high pressures of the RTG's operating environment resulting from the alpha decay of the 238-plutonium dioxide fuel. However, 238-plutonium is also a powerful neutron source. Therefore, the RTG operating environment produces large amounts of 3-helium and neutron displacement damage over the 30 year life of the RTG. The literature to date shows that there has been very little work focused on the mechanical properties of irradiated tantalum and tantalum alloys and none at the fluence levels associated with a RTG operating environment. The minimum, reactor related, work that has been reported shows that these alloys tend to follow trends seen in the behavior of other BCC alloys under irradiation. An understanding of these mechanisms is important for the confident extrapolation of mechanical-property trends to the higher doses and gas levels corresponding to actual service lifetimes. When comparing the radiation effects between samples of Ta-10%W and T-111 (Ta-8%W-2%Hf) subjected to identical neutron fluences and environmental conditions at temperatures <0.3Tm (˜700 °C), evidence suggests the possibility that T-111 will exhibit higher levels of internal damage accumulation and degradation of mechanical properties compared to Ta-10%W.

  5. Shape memory alloys applied to improve rotor-bearing system dynamics - an experimental investigation

    DEFF Research Database (Denmark)

    Enemark, Søren; Santos, Ilmar; Savi, Marcelo A.

    2015-01-01

    hysteretic stress-strain relations which may be utilized for damping purposes. These ideas are tested in this study on a dedicated test-rig, consisting of a rigid shaft and disc held vertically by passive magnetic bearings, where the damping is low. The bearing housings is flexibly supported by shape memory...... alloy helical springs, and because of high dynamic coupling between shaft and bearing housing, the shape memory alloy springs are able to reduce vibration in the shaft. The shape memory alloy springs are characterized by force-displacement tests in different temperatures. Transients of step...... perturbations and mass imbalance responses of the rotor-bearing system at different temperatures and excitation frequencies are carried out to determine the dynamic behaviour of the system. The behaviour and the performance in terms of vibration reduction and system adaptability are compared against a benchmark...

  6. Microbiologically induced corrosion of aluminum alloys in fuel-oil/aqueous system.

    Science.gov (United States)

    Yang, S S; Lin, J Y; Lin, Y T

    1998-09-01

    To investigate the microbiologically induced corrosion of aluminum alloys in fuel-oil/aqueous system, aluminum alloys A356, AA 5052, AA 5083 and AA 6061 were chosen as the test alloys and Cladosporium and several fuel-oil contaminated microbes isolated in Taiwan were used as test organisms. Aluminum alloy AA 5083 in fuel-oil/aqueous system was the most susceptible material for microbial corrosion, then followed by aluminum alloys AA 5052 and A356, and AA 6061 was more resistant to microbial aggression. Mixed culture had high capability of corrosion, then followed by Penicillium sp. AM-F5, Fusarium sp. AM-F1, Pseudomonas aeruginosa AM-B5, Ps. fluorescens AM-B9, C. resinae ATCC 22712, Penicillium sp. AM-F2, Candida sp. AM-Y1 and Ps. aeruginosa AM-B11. From energy dispersive spectrometer analysis, aluminum and magnesium contents decreased in the corrosion area, while chlorine and sulfur contents increased. The major organic acid produced in fuel-oil/aqueous system was acetic acid, and the total organic acids content had a positive correlation with the degree of microbial corrosion. PMID:10496152

  7. Computer simulations of phase decomposition in real alloy systems based on the modified Khachaturyan diffusion equation

    International Nuclear Information System (INIS)

    Recently, Khachaturyan's group proposed a new calculation method for phase decomposition on the basis of the Onsager equation. IN the present study, the authors modified the Khachaturyan diffusion equation to allow simulation of the phase decomposition in actual alloy systems. Two-dimensional (2-D) computer calculations are performed for the phase decompositions of Al-Zn, Cu-Co, and Fe-Mo binary systems by using the thermodynamic data related to the equilibrium phase diagrams. The calculated microstructures are very similar to the actual micrographs experimentally obtained for these alloys

  8. The Effect of Novel Mercapto Silane Systems on Resin Bond Strength to Dental Noble Metal Alloys.

    Science.gov (United States)

    Lee, Yangho; Kim, Kyo-Han; Kim, Young Kyung; Son, Jun Sik; Lee, Eunkyung; Kwon, Tae-Yub

    2015-07-01

    Self-assembled monolayers of thiols (RSH), which are key elements in nanoscience and nanotechnology, have been used to link a range of materials to planar gold surfaces or gold nanoparticles. In this study, the adhesive performance of mercapto silane systems to dental noble metal alloys was evaluated in vitro and compared with that of commercial dental primers. Dental gold-palladium-platinum (Au-Pd-Pt), gold-palladium-silver (Au-Pd-Ag), and palladium-silver (Pd-Ag) alloys were used as the bonding substrates after air-abrasion (sandblasting). One of the following primers was applied to each alloy: (1) no primer treatment (control), (2) three commer- cial primers: V-Primer, Metal Primer II, and M.L. Primer, and (3) two experimental silane primer systems: 2-step application with 3-mercaptopropyltrimethoxysilane (SPS) (1.0 wt%) and then 3-methacryloxypropyltrimethoxysilane (MPS) (1.0 wt%), and a silane blend consisting of SPS and MPS (both 1.0 wt%). Composite resin cylinders with a diameter of 2.38 mm were bonded to the surfaces and irradiated for 40 sec using a curing light. After storage in water at 37 °C for 24 h, all the bonded specimens were thermocycled 5000 times before the shear bond strength test. Regardless of the alloy type, the mercapto silane systems (both the 2-step and blend systems) consistently showed superior bonding performance than the commercial primers. Contact angle analysis of the primed surfaces indicated that higher resin bond strengths were produced on more hydrophilic alloy surfaces. These novel mercapto silane systems are a promising alternative for improving resin bonding to dental noble metal alloys. PMID:26373046

  9. Self-healing electrical insulating coating processes for vanadium alloy-lithium systems

    International Nuclear Information System (INIS)

    The existing technological approaches for the formation of nitride- and oxide-based self-healing electrical insulating coatings for vanadium alloy-lithium systems are considered. The results of the property study of coatings applied from liquid lithium containing Al, N, Si, B additions on various modes are considered. The formation conditions of AlN-based coatings with scale specific electrical resistivity (∼50 Ω m) on the V-4Ti-4Cr vanadium alloy are determined. The results of formation and stability research of coatings on the V-4Ti-4Cr vanadium alloy in convectional and forced circulating lithium with Al and N additions in the homogeneous and heterogeneous lithium systems are discussed

  10. An Automated System To Classify Alloy Steel Surface Using Contourlet Transform

    Directory of Open Access Journals (Sweden)

    Mr.N.Vimalraj

    2014-01-01

    Full Text Available Surface defect detection of metallic surfaces is a major challenge in any manufacturing industry. In this paper, an automated system to classify alloy steel surface based on contourlet transform is presented. As the contourlet transform is a multi resolution analysis, texture present in alloy steel surface is represented in various scales and directions. The image is decomposed at various scales and directions and the energy features are extracted. By analyzing the energies from the trained images, the best set that distinguishes the surface into defect or non defect is chosen for classification. The classification results are evaluated on the given set of images of alloy steel surface and the performance of the system is evaluated.

  11. Study on a multi-component palladium alloy membrane for the fusion fuel cleanup system

    International Nuclear Information System (INIS)

    Demonstration Tests with (D,T)2 gas to examine the reported hydrogen embrittlement and helium damage on Pd and Pd-Ag binary alloy are needed for a palladium alloy membrane for its application to a fusion fuel system. T2-gas circulating and T2-gas immersion tests with a multi-component palladium alloy, which had been selected for use of tritum purification, have been performed in the Tritium Systems Test Assembly(TSTA) at Los Alamos National Laboratory under the Japan/US Fusion Cooperation Program. Mechanical tensile tests and metallographic studies have been conducted in these durability tests. Similar tests had been performed on the same material under tritium-free atmospheres(H2, N2) to analyse the data obtained by the T2-gas tests. This report describes the results of the mechanical tensile tests and the test conditions. (author)

  12. Shape memory alloy heat engines and energy harvesting systems

    Science.gov (United States)

    Browne, Alan L; Johnson, Nancy L; Keefe, Andrew C; Alexander, Paul W; Sarosi, Peter Maxwell; Herrera, Guillermo A; Yates, James Ryan

    2013-12-17

    A heat engine includes a first rotatable pulley and a second rotatable pulled spaced from the first rotatable pulley. A shape memory alloy (SMA) element is disposed about respective portions of the pulleys at an SMA pulley ratio. The SMA element includes first spring coil and a first fiber core within the first spring coil. A timing cable is disposed about disposed about respective portions of the pulleys at a timing pulley ratio, which is different than the SMA pulley ratio. The SMA element converts a thermal energy gradient between the hot region and the cold region into mechanical energy.

  13. Controllable Catalysis with Nanoparticles: Bimetallic Alloy Systems and Surface Adsorbates

    KAUST Repository

    Chen, Tianyou

    2016-05-16

    Transition metal nanoparticles are privileged materials in catalysis due to their high specific surface areas and abundance of active catalytic sites. While many of these catalysts are quite useful, we are only beginning to understand the underlying catalytic mechanisms. Opening the “black box” of nanoparticle catalysis is essential to achieve the ultimate goal of catalysis by design. In this Perspective we highlight recent work addressing the topic of controlled catalysis with bimetallic alloy and “designer” adsorbate-stabilized metal nanoparticles.

  14. Crystallization behavior and magnetic properties in High Fe content FeBCSiCu alloy system

    Energy Technology Data Exchange (ETDEWEB)

    Fan, X.D., E-mail: fanxd@seu.edu.cn; Shen, B.L., E-mail: blshen@seu.edu.cn

    2015-07-01

    High Fe content FeBCSiCu nanocrystalline alloys are prepared by annealing melt-spun amorphous ribbons with aim at increasing saturation magnetic flux density. Microstructures identified by XRD and TEM reveal that Cu addition inhibits the surface crystallization of Fe{sub 86}B{sub 7}C{sub 7} alloy and improve its glass-forming ability. Activation energy of crystallization calculated by Kissinger's equation indicates that both Cu and Si addition promotes the precipitation of α-Fe phase and improves the thermal stability. VSM and DC B–H loop tracer measurements show that the Fe{sub 85.5}B{sub 7}C{sub 6}Si{sub 1}Cu{sub 0.5} nanocrystalline alloy exhibits high saturation magnetic flux density of 1.8 T and low coercivity of 10 A/m, respectively. AC properties measured by AC B–H analyzer show this alloy exhibits low core loss of 0.35 W/kg at 1 T at 50 Hz. Low material cost and convenient productivity make the Fe{sub 85.5}B{sub 7}C{sub 6}Si{sub 1}Cu{sub 0.5} nanocrystalline alloy an economical application in industry. - Highlights: • Cu addition inhibits the surface crystallization and improves the GFA. • The competitive formation of Fe{sub 3}C and α-Fe phase impedes the devitrification. • Fe{sub 85.5}B{sub 7}C{sub 6}Si{sub 1}Cu{sub 0.5} nanocrystalline alloy exhibits excellent magnetic properties. • The alloy system has an economical advantage and convenient productivity.

  15. Development of a magnesium secondary alloy system for mixed magnesium post-consumer scrap

    International Nuclear Information System (INIS)

    Six alloys were prepared by high pressure die casting in order to develop a magnesium secondary alloy system for mixed post-consumer scrap. The alloys were investigated with regard to intermetallic phases, grain structures, mechanical properties and performance in the salt spray test. The results are discussed in relation to the characteristics of the high pressure die casting process. The effect of contamination by copper and compensation for this effect by the addition of zinc were thoroughly investigated for the most promising alloy. It is evident that the alloying elements strontium, silicon and calcium are incorporated in the ternary Zintl phase Sr6.33Mg16.67Si13, while aluminium, zinc, copper and magnesium form the tau-phases Mg32(Alx,Cu1−x)49 and Mg32(Al,Zn)49. The two tau-phases can merge due to isomorphism. Mg32(Al,Zn)49 ensures improved corrosion resistance after the addition of copper

  16. Activity of hydrogen in metal-hydrogen systems: strontium, thorium-nitrogen, and vanadium alloys

    International Nuclear Information System (INIS)

    The dissolution of H gas has been studied using pressure-composition isotherms in Sr, Th-N and V alloys containing either Nb, Cr or Ti. Direct H equilibrium vapor pressure measurements were performed in the Sr-H and Th-N-H systems at 973 to 11730K and 623 to 11230K, respectively. Isopiestic solubility was used to measure the H equilibrium pressures for the V alloys at 223 to 4730K. In all the alloys studied, the reaction of hydrogen with the metal phase was exothermic and hydrogen followed Sieverts' law over a considerable range of hydrogen concentration. The enthalpy of solution of H in the Sr and the enthalpy of formation of ThNH/sub x/ are -14.3 +- 1.2 kcal;/mol H and -16.3 +- 1.5 kcal/mol H2, respectively. Enthalpies of solution of H for the V alloys ranged from -8.0 to -10.5 +- 0.3 kcal/mol H. Additions of T to V dramatically enhanced the isopiestic solubility of H, Cr significantly reduced the solubility and Nb moderately increased the solubility. Sieverts' law behavior for H in the V alloys showed that substitutional atoms did not act as deep traps for H

  17. Development of a magnesium secondary alloy system for mixed magnesium post-consumer scrap

    Energy Technology Data Exchange (ETDEWEB)

    Fechner, Daniel, E-mail: dfechner@tuev-nord.de; Blawert, Carsten; Hort, Norbert; Dieringa, Hajo; Kainer, Karl Ulrich

    2013-08-01

    Six alloys were prepared by high pressure die casting in order to develop a magnesium secondary alloy system for mixed post-consumer scrap. The alloys were investigated with regard to intermetallic phases, grain structures, mechanical properties and performance in the salt spray test. The results are discussed in relation to the characteristics of the high pressure die casting process. The effect of contamination by copper and compensation for this effect by the addition of zinc were thoroughly investigated for the most promising alloy. It is evident that the alloying elements strontium, silicon and calcium are incorporated in the ternary Zintl phase Sr{sub 6.33}Mg{sub 16.67}Si{sub 13}, while aluminium, zinc, copper and magnesium form the tau-phases Mg{sub 32}(Al{sub x},Cu{sub 1−x}){sub 49} and Mg{sub 32}(Al,Zn){sub 49}. The two tau-phases can merge due to isomorphism. Mg{sub 32}(Al,Zn){sub 49} ensures improved corrosion resistance after the addition of copper.

  18. Mechanical alloying in Fe2O3-MO (M: Zn, Ni, Cu, Mg) systems

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Gerward, Leif; Mørup, Steen

    1999-01-01

    Mechanical alloying processes in four Fe2O3MO (M: Zn, Ni, Cu, Mg) systems by high-energy ball milling from simple oxide powder mixtures in both open and closed tungsten carbide containers have been investigated by x-ray powder diffraction and Mossbauer spectroscopy. Mechanisms for the formation of......-energy ball milling under the conditions used here. The dominant alloying mechanism depends on the interdiffusion at relatively low temperatures. The experimental results may also be explained by the crystal structures of the reactants and the ferrites....

  19. Phase structures and morphologies of rapidly solidified intermetallic alloys in Nb-Ti-Al ternary system

    International Nuclear Information System (INIS)

    In order to evaluate the potential of applying RSP (rapid solidification processing) to the intermetallic alloys in the Nb-Ti-Al ternary system, the phase structures and morphologies of splat quenched alloys among TiAl, Ti3Al, γ1 and TiAl3, NbAl3 phases were investigated by optical microscopy, transmission electron microscopy and X-ray and electron diffraction. A phase constitution map under a rapid solidified state is given. The modification of microstructures, formation of metastable phases, solubility extension and change in solidification path are presented and discussed. Some comparisons are made with the results of previous workers

  20. Physicochemical properties of alloys of PbTe-Fe2Te3 system

    International Nuclear Information System (INIS)

    Physicochemical and some electric properties of PbTe-Fe2Te3 cut alloys are investigated. State diagram for this system where at 1145 K PbFe2Te4 new ternary compound is formed, is plotted. Temperature dependences of electric parameters have shown that PbFe2Te4 compound is semiconductor with conductivity of electron type

  1. Physical properties of the complex metallic alloy phases in the Al-Pd-Mn system

    OpenAIRE

    Dolinsek, Janez; Jaglicic, Zvonko; Smontara, Ana

    2005-01-01

    Abstract The Al-Pd-Mn system of intermetallics contains complex metallic alloy (CMA) phases, whose crystal structures are based on giant unit cells comprising up to more than a thousand atoms per cell. We performed investigation of the magnetic, electrical, thermal transport and thermoelectric properties of the i' phase and the related ? phase on single-crystalline samples.

  2. Formation of hydrotalcite coating on the aluminum alloy 6060 in spray system

    DEFF Research Database (Denmark)

    Zhou, Lingli; Friis, Henrik; Roefzaad, Melanie;

    2016-01-01

    Coatings with the composition of Li-Al-NO3 hydrotalcite were formed on the Al alloy 6060 using a spray system. The coatings consist of crystals with a typical hydrotalcite structure. Dense, uniform and blade-like flakes cover completely the surface of the Al substrate. The coatings display a mult...

  3. Enhancement and Commercialization of the Alloy Selection System for Elevated Temperatures - ASSET

    Energy Technology Data Exchange (ETDEWEB)

    Randy C. John

    2005-11-05

    A corrosion engineering information system was created to manage, correlate and predict corrosion of alloys and also to use thermochemical calculations to predict the occurrence of dominant corrosion mechanisms in hot gases found in many different chemical processes and other related industrial processes.

  4. Design of lead-free candidate alloys for high-temperature soldering based on the Au–Sn system

    DEFF Research Database (Denmark)

    Chidambaram, Vivek; Hattel, Jesper Henri; Hald, John

    2010-01-01

    Au–Sn based candidate alloys have been proposed as a substitute for high-lead content solders that are currently being used for high-temperature soldering. The changes in microstructure and microhardness associated with the alloying of Ag and Cu to the Au rich side as well to the Sn rich side of...... the Au–Sn binary system were explored in this work. Furthermore, the effects of thermal aging on the microstructure and microhardness of these promising Au–Sn based ternary alloys were investigated. For this purpose, the candidate alloys were aged at a lower temperature, 150°C for up to 1week and...

  5. Precipitation hardening in ternary alloys of the Al-Sc-Cu and Al-Sc-Si systems

    International Nuclear Information System (INIS)

    The processes of precipitation hardening in cast ternary alloys of the Al-Sc-Cu and Al-Sc-Si systems were studied in the temperature range of aging from 100 to 450 C and at exposures to 200 h. It was shown that the CuAl2 and ScAl3 phases were involved in the process of aging in ternary Al-Sc-Cu alloys, and the Si and V (AlSiSc) phases, in ternary Al-Sc-Si alloys with excess silicon in a supersaturated solid solution. The V phase was for the first time revealed as the hardening phase in aluminum alloys

  6. Thermodynamic analysis of the change of solid solubility in a binary system processed by mechanical alloying

    International Nuclear Information System (INIS)

    Using a non-equilibrium process, it is possible to extend the solid solubility range in metallic systems. Therefore, the main objective of this work was to apply a thermodynamic model to predict the change in the solubility limit of systems with positive enthalpy mixing (Cu-Cr and Fe-Cu) processed by mechanical alloying. It was found that increasing the density of crystalline defects alters the solubility limit in these binary systems

  7. A Computational Investigation of Precipitates in Mg-RE Alloys With Applications To Mg-X Systems

    Science.gov (United States)

    Issa, Ahmed

    Increasing fuel efficiency in transportation vehicles is a major policy goal for both government and auto and aerospace manufacturers. Lightweight structural materials, such as magnesium alloys, hold great promise in enabling such fuel efficiency gains. Understanding the controlling factors in Mg alloy strengthening is crucial for the rational design of structurally strong and inexpensive Mg alloys. In this work, we seek to understand the energetic underpinnings giving rise to a class of remarkably strong Mg alloys: Mg-RE systems. We use first-principles methods to efficiently explore seventeen Mg-RE systems, drawing out broad patterns and distilling our knowledge into simple design rules for Mg alloys. We begin by investigating the controlling factors for the Mg-strengthening prismatic plate precipitates in Mg-RE systems, discovering the critical role of strain in such systems. We then proceed to investigate the surprising role of interfacial energies in determining the course of the Mg-RE precipitation reactions. Using strain and interfacial energies, we construct a phase-field model which accurately depicts the precipitate morphology as a function of time and size in a Mg-Nd system. Finally, we combine our gained insights to implement a computational alloy design scheme on a large portion of the periodic table where we seek Mg-strengthening solutes. Our work advances the understanding of strengthening in Mg alloys and lays the groundwork for full scale computational alloy design.

  8. Application of advanced austenitic alloys to fossil power system components

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, R.W.

    1996-06-01

    Most power and recovery boilers operating in the US produce steam at temperatures below 565{degrees}C (1050{degrees}F) and pressures below 24 MPa (3500 psi). For these operating conditions, carbon steels and low alloy steels may be used for the construction of most of the boiler components. Austenitic stainless steels often are used for superheater/reheater tubing when these components are expected to experience temperatures above 565{degrees}C (1050{degrees}F) or when the environment is too corrosive for low alloys steels. The austenitic stainless steels typically used are the 304H, 321H, and 347H grades. New ferritic steels such as T91 and T92 are now being introduced to replace austenitic: stainless steels in aging fossil power plants. Generally, these high-strength ferritic steels are more expensive to fabricate than austenitic stainless steels because the ferritic steels have more stringent heat treating requirements. Now, annealing requirements are being considered for the stabilized grades of austenitic stainless steels when they receive more than 5% cold work, and these requirements would increase significantly the cost of fabrication of boiler components where bending strains often exceed 15%. It has been shown, however, that advanced stainless steels developed at ORNL greatly benefit from cold work, and these steels could provide an alternative to either conventional stainless steels or high-strength ferritic steels. The purpose of the activities reported here is to examine the potential of advanced stainless steels for construction of tubular components in power boilers. The work is being carried out with collaboration of a commercial boiler manufacturer.

  9. Effect of cobalt content on electrochemical performance of La-Mg-Ni system (Ce2Ni7-type) electrode alloys

    Institute of Scientific and Technical Information of China (English)

    WANG Xinlin; DONG Xiaoping; ZHANG Yanghuan; GUO Shihai; Lü Fanxiu

    2008-01-01

    In order to improve the cyclic stability of La-Mg-Ni system (Ce2Ni7-type) alloy electrode, small amount of Co was added in La0.75Mg0.25Ni3.5 alloy. The effect of Co on electrochemical performance and microstructure of the alloys were investigated in detail. XRD results showed that the alloys had multiphase structure composed of (La, Mg)2Ni7, LaNi5 and small amount of LaNi2 phases. The discharge capacity of the alloys first increased and then decreased with increasing Co content. At a discharge current density of 900 mA/g, the HRD of the alloy electrodes increased from 81.3% (x=0) to 89.2 % (x=0.2), and then reduced to 87.8 % (x=0.6). After 60 charge/discharge cycles, the capacity retention rate of the alloys enhanced from 52.67% to 61.32%, and the capacity decay rate of the alloys decreased from 2.60 to 2.05 mAh/g per cycle with increasing Co content. The obtained results by XPS and XRD showed that the fundamental reasons for the capacity decay of the La-Mg-Ni system (Ce2Ni7-type) alloy electrodes were corrosion and oxidation as well as passivation of Mg and La in alkaline solution.

  10. Alloying effects on the hydrogen-storage capability of Pd–TM–H (TM = Cu, Au, Pt, Ir) systems

    International Nuclear Information System (INIS)

    Highlights: • Magnetic susceptibilities and hydrogen capabilities for Pd–TM–H were simultaneously measured. • Magnetic susceptibilities of Pd–Pt–H and Pd–Ir–H exhibited different behavior from Pd–H. • Hydrogen capabilities of Pd–TM were decreased with increasing TM content. • Alloying Pd with Pt and Ir reduced more its hydrogen capability than alloying with Cu and Au. • These results were explained by change on band structure above Fermi level by alloying. - Abstract: Pressure–composition isotherms and the magnetic susceptibilities of Pd–TM–H (TM = Cu, Au, Pt, and Ir) systems were measured at ambient temperature, and the effects of alloying between Pd and transition metals on the hydrogen storage capability of these Pd–TM alloys were investigated by considering their electronic band structures. All of the magnetic susceptibilities for the Pd–TM–H systems decreased linearly with hydrogen uptake. For the Pd–Cu alloy, the magnetic susceptibility was nearly zero at the terminal composition of hydrogen in the plateau region obtained from the pressure–composition isotherm, and the terminal composition decreased with increasing Cu substitution. These results indicated that the hydrogen-storage capability was proportional to the amount of unoccupied d states in the electronic band structure of the Pd–Cu alloy. The Pd–Au–H system exhibited substantially the same behavior as the Pd–Cu–H system. For the Pd–Pt and Pd–Ir alloys, the magnetic susceptibility at the terminal composition of hydrogen in the plateau exhibited a finite positive value, indicating that the unoccupied d states in the Pd–Pt and Pd–Ir alloys were not filled when the maximum quantity of hydrogen was stored in the alloys. These finite magnetic susceptibilities at the terminal composition of hydrogen in the plateau region were explained by the structural modification of the unoccupied d states in the electronic band structures due to alloying

  11. Effect of phase composition on the corrosion properties of alloys of the magnesium-yttrium system in neutral solutions

    International Nuclear Information System (INIS)

    A study is made of the effect of phase composition on the corrosive dissolution of binary alloys of the system magnesium-8.2% yttrium. It is shown that the appearance of the intermetallide Mg24Y5 - being the effective cathode - intensifies self-dissolution of the alloy under conditions of anodic galvanostatic polarization

  12. Multistrand, Fast Reaction, Shape Memory Alloy System for Uninhabited Aerial Vehicle Flight Control

    OpenAIRE

    M. Brennison; Barrett, R. M.; Kerth, L

    2012-01-01

    This paper details an investigation of shape memory alloy (SMA) filaments which are used to drive a flight control system with precision control in a real flight environment. An antagonistic SMA actuator was developed with an integrated demodulator circuit from a JR NES 911 subscale UAV actuator. Most SMA actuator studies concentrate on modeling the open-loop characteristics of such a system with full actuator performance modeling. This paper is a bit different in that it is very practically ...

  13. Thermodynamic properties of alloys of the binary In-La system

    Science.gov (United States)

    Shevchenko, M. A.; Ivanov, M. I.; Berezutski, V. V.; Sudavtsova, V. S.

    2016-06-01

    The thermochemical properties of melts of the binary In-La system were studied by the calorimetry method at 1250-1480 K over the whole concentration interval. It was shown that significant negative heat effects of mixing are characteristic features for these melts. Using the ideal associated solution (IAS) model, the activities of components, Gibbs energies and the entropies of mixing in the alloys, and the phase diagram of this system were calculated. They agree with the data from literature.

  14. Bioinspired Soft Actuation System Using Shape Memory Alloys

    Directory of Open Access Journals (Sweden)

    Matteo Cianchetti

    2014-07-01

    Full Text Available Soft robotics requires technologies that are capable of generating forces even though the bodies are composed of very light, flexible and soft elements. A soft actuation mechanism was developed in this work, taking inspiration from the arm of the Octopus vulgaris, specifically from the muscular hydrostat which represents its constitutive muscular structure. On the basis of the authors’ previous works on shape memory alloy (SMA springs used as soft actuators, a specific arrangement of such SMA springs is presented, which is combined with a flexible braided sleeve featuring a conical shape and a motor-driven cable. This robot arm is able to perform tasks in water such as grasping, multi-bending gestures, shortening and elongation along its longitudinal axis. The whole structure of the arm is described in detail and experimental results on workspace, bending and grasping capabilities and generated forces are presented. Moreover, this paper demonstrates that it is possible to realize a self-contained octopus-like robotic arm with no rigid parts, highly adaptable and suitable to be mounted on underwater vehicles. Its softness allows interaction with all types of objects with very low risks of damage and limited safety issues, while at the same time producing relatively high forces when necessary.

  15. Influence of system and degree of alloying on the parameters of shape-memory effect in titanium alloys

    International Nuclear Information System (INIS)

    The influence of chemical composition, compression degree, heating rate on characteristics of shape memory effect of Ti-Nb, Ti-V, Ti-Al-V, Ti-Al-V-Cr is studied. A comparative analysis is made between experimentally defined values of restitution deformation degree and calculated values of crystographically reversible deformation of martensitic transformation. Main reasons for non complete restitution of form in the titanium base alloy are as the formation of embrittling ω-phase in titanium alloys of critical composition with a β-stabilizer; the proximity of martensitic transformation-induced stresses and sliding ones on deformation; low thermal stability of β- and α''-phase of titanium alloys in the range of temperatures of reverse martensitic transformation. Aluminium and chromium alloying of titanium alloys permits increasing the value of restitution deformation due to the suppression of ω-phase formation during quenching of critical composition alloys and the increase of sliding stresses. The optimal composition of the titanium alloy is proposed

  16. Interaction of ions in water system containing copper-zinc alloy for boiler energy saving

    Institute of Scientific and Technical Information of China (English)

    MING Xing; LIANG Jinsheng; OU Xiuqin; TANG Qingguo; DING Yan

    2006-01-01

    Copper-zinc alloy element for boiler energy saving was put in the intake of simulated boiler system to investigate the interaction and transfer of ions in water system both theoretically and experimentally. The fouling was analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray detector (EDX). The results show that the transfer of calcium and magnesium ions in heat-transfer-surface-water system is affected by zinc ions dissolved from the alloy because of primary battery reaction. Some calcium ions of calcium carbonate crystal are replaced by zinc ions, the growth of aragonite crystal nucleus is retarded, and the transition of calcium carbonate from aragonite to calcite is hampered.

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

    International Nuclear Information System (INIS)

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

  18. Weldability and joining techniques for advanced fossil energy system alloys

    Energy Technology Data Exchange (ETDEWEB)

    Lundin, C.D.; Qiao, C.Y.P.; Liu, W.; Yang, D.; Zhou, G.; Morrison, M. [Univ. of Tennessee, Knoxville, TN (United States)

    1998-05-01

    The efforts represent the concerns for the basic understanding of the weldability and fabricability of the advanced high temperature alloys so necessary to affect increases in the efficiency of the next generation Fossil Energy Power Plants. The effort was divided into three tasks with the first effort dealing with the welding and fabrication behavior of 310HCbN (HR3C), the second task details the studies aimed at understanding the weldability of a newly developed 310TaN high temperature stainless (a modification of 310 stainless) and Task 3 addressed the cladding of austenitic tubing with Iron-Aluminide using the GTAW process. Task 1 consisted of microstructural studies on 310HCbN and the development of a Tube Weldability test which has applications to production welding techniques as well as laboratory weldability assessments. In addition, the evaluation of ex-service 310HCbN which showed fireside erosion and cracking at the attachment weld locations was conducted. Task 2 addressed the behavior of the newly developed 310 TaN modification of standard 310 stainless steel and showed that the weldability was excellent and that the sensitization potential was minimal for normal welding and fabrication conditions. The microstructural evolution during elevated temperature testing was characterized and the second phase particles evolved upon aging were identified. Task 3 details the investigation undertaken to clad 310HCbN tubing with Iron Aluminide and developed welding conditions necessary to provide a crack free cladding. The work showed that both a preheat and a post-heat was necessary for crack free deposits and the effect of a third element on the cracking potential was defined together with the effect of the aluminum level for optimum weldability.

  19. Determination of mutual diffusion coefficients in quaternary alloy systems

    International Nuclear Information System (INIS)

    Procedures of experimental study of mutual diffusion in four-component system are developed, limit ratios for diffusion coefficients are found at the transition from four component system to three-component one and experimental check of some of these ratios is carried out. Concentrational dependence of complete matrix of outer diffusion coefficients in Fe-Cr-Ni-Co system is determined. Limit correlations for this system are checked up at cobalt concentration yielding to zero

  20. MgB{sub 2} thin films grown on graphene/Ni–Mo alloy system

    Energy Technology Data Exchange (ETDEWEB)

    Linghu, Kehuan, E-mail: linghukehuan@126.com [School of Physics and State Key Laboratory for Artificial Structure and Mesoscopic Physics, Peking University, Beijing 100871 (China); Song, Qingjun [School of Physics and State Key Laboratory for Artificial Structure and Mesoscopic Physics, Peking University, Beijing 100871 (China); Collaborative Innovation Center of Quantum Matter, Beijing 100871 (China); Zhang, Huai [School of Physics and State Key Laboratory for Artificial Structure and Mesoscopic Physics, Peking University, Beijing 100871 (China); Yang, QianQian [College of Applied Sciences, Beijing University of Technology, Beijing 100124 (China); Zhang, Jibo; Wu, Qianhong; Nie, Ruijuan [School of Physics and State Key Laboratory for Artificial Structure and Mesoscopic Physics, Peking University, Beijing 100871 (China); Dai, Lun [School of Physics and State Key Laboratory for Artificial Structure and Mesoscopic Physics, Peking University, Beijing 100871 (China); Collaborative Innovation Center of Quantum Matter, Beijing 100871 (China); Feng, Qingrong; Wang, Furen [School of Physics and State Key Laboratory for Artificial Structure and Mesoscopic Physics, Peking University, Beijing 100871 (China)

    2015-09-15

    Highlights: • Depositing MgB{sub 2} thin films on graphene/Ni–Mo alloy substrate by HPCVD is a completely new method. • The growth of MgB{sub 2} thin films in this system lays a good foundation of depositing MgB{sub 2} thick films. • We directly deposite MgB{sub 2} films on graphene(without transferring) which keeps graphene’s original morphology and properties. - Abstract: 200 nm Ni film is coated on 25 μm thick Mo foil, and graphene is grown on the Ni–Mo system by CVD method. After the annealing process of CVD, the Ni/Mo bilayer transforms into Ni–Mo alloy, then we have successfully fabricated MgB{sub 2} films on graphene/Ni–Mo alloy system via the hybrid physical–chemical vapor deposition (HPCVD) technique. The transition temperature T{sub c} onset is 38.25 K with a corresponding transition width of 0.75 K. The average thickness of MgB{sub 2} films is 200 nm (25% concentration B{sub 2}H{sub 6}). The critical current density derives from the magnetization measurement at 5 K is, j{sub c} (5 K, 0 T) = 9.6 × 10{sup 6} A/cm{sup 2}. We can easily deposite MgB{sub 2} on graphene/Ni–Mo alloy system with a lower B{sub 2}H{sub 6} concentration and less gas flow, which lays a good foundation for depositing MgB{sub 2} thick films. The graphene in this system is multilayer and with defects, it may act like an intermediary film for the growth of MgB{sub 2}, or a carbon-doping source.

  1. On amorphization and nanocomposite formation in Al–Ni–Ti system by mechanical alloying

    Indian Academy of Sciences (India)

    K Das; G K Dey; B S Murty; S K Pabi

    2005-11-01

    Amorphous structure generated by mechanical alloying (MA) is often used as a precursor for generating nanocomposites through controlled devitrification. The amorphous forming composition range of ternary Al–Ni–Ti system was calculated using the extended Miedema's semi-empirical model. Eleven compositions of this system showing a wide range of negative enthalpy of mixing (− mix) and amorphization (− amor) of the constituent elements were selected for synthesis by MA. The Al88Ni6Ti6 alloy with relatively small negative mix (−0.4 kJ/mol) and amor (−14.8 kJ/mol) became completely amorphous after 120 h of milling, which is possibly the first report of complete amorphization of an Al-based rare earth element free Al–TM–TM system (TM = transition metal) by MA. The alloys of other compositions selected had much more negative mix and amor; but they yielded either nanocomposites of partial amorphous and crystalline structure or no amorphous phase at all in the as-milled condition, evidencing a high degree of stability of the intermetallic phases under the MA environment. Hence, the negative mix and amor are not so reliable for predicting the amorphization in the present system by MA.

  2. Design, manufacturing and current use of hard coating system of Aluminium and its alloys

    International Nuclear Information System (INIS)

    Due to the light weight and high specific strength of Aluminum and its alloys, they have found many industrial applications. These alloys have good formability, corrosion resistivity and good electrical and thermal conductivities, but because of their weak tribological properties in applications where the Al surfaces are in moving contact with each other, they do not have enough wear resistance. Decorative and protective anodizing layers of 10-25 micron thick are made for this reason. The search for the denser and heavier co stings (50 to 200 micron) has led to the development of hard anodizing. Coatings provide abrasion resistance for sliding wear applications, erosion and corrosion resistance, as well as electrical and thermal insulation properties. In this research work a hard anodizing system consists of a refrigeration system capable of reducing the temperature of electrolyte to 10deg C, to be controlled within ±1deg C, and a complex rectifier for providing and maintaining the current during the anodizing period was designed and fabricated. The system is now in daily operational condition in electrochemistry laboratory. In this research work the 8079 series aluminum alloys were hard coated using hard anodizing system. the results have indicated that by increasing the coating thickness the wear rate is reduced considerably and the load carrying capacity is increased to some extent. The mechanism in thin coatings was demonstrated to be brittle fracture

  3. The relationship between viscosity and glass forming ability of Al-(Ni)-Yb alloy systems

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The dynamic viscosity of Al-Yb and Al-Ni-Yb superheated melts was measured using a torsional oscillation viscometer. The results show that the temperature dependence of viscosity fits the Arrhenius law well and the fitting factors are calculated. The amorphous ribbons of these alloys were produced by the melt spinning technique and the thermal properties were characterized by using a differential scanning calorimetry (DSC). E (the activation energy for viscous flow), which reflects the change rate of viscosity, has a good negative relation with the GFA in both Al-Yb and Al-Ni-Yb systems. However, there is no direct relation between liquidus viscosity (ηL) and GFA. The superheated fragility M can predict GFA in Al-Yb or Al-Ni-Yb alloy system.

  4. Thermodynamic prediction of thixoformability in alloys based on the Al-Si-Cu and Al-Si-Cu-Mg systems

    Energy Technology Data Exchange (ETDEWEB)

    Liu, D. [Department of Engineering, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Atkinson, H.V. [Department of Engineering, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Jones, H. [Department of Engineering Materials, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield S1 3JD (United Kingdom)

    2005-08-15

    Most commercial semi-solid processing (of which thixoforming is one type) utilises the conventional casting alloys A356 and A357. There is, however, a demand to widen the range of alloys, including those with higher performance which tend to show poor characteristics for thixoforming. Thermodynamic calculation packages, such as MTDATA, provide a tool for predicting thixoformability. Here, the effects of compositional variations, in particular the effect of added copper on the thixoformability of alloy A356 and the effect of added silicon on the thixoformability of alloy 2014, have been investigated using MTDATA thermodynamic and phase equilibrium software combined with the MTAL database. Criteria for thixoformability are identified and a range of alloy compositions based on Al-Si-Cu and Al-Si-Cu-Mg evaluated in relation to these criteria. Compositions which satisfy these criteria include: 308 (Al-5.5Si-4.5Cu); 319 (Al-6Si-3.5Cu); 238 (Al-10Cu-4Si-0.3Mg); 355 (Al-5Si-1.3Cu-0.5Mg); 2014 based alloys Al-4.4Cu-0.5Mg-(4-6)Si; and a range of alloys (7.5 Si + Cu 9 and 1.5 Si/Cu 2.33) and alloys (9 < Si + Cu 10 and Si/Cu = 1.5) based on the Al-Si-Cu-Mg system.

  5. Design and fabrication of a mechanical alloying system for preparing intermetallic, nanocrystalline, amorphous and quasicrystalline compounds

    International Nuclear Information System (INIS)

    In this work a grinding system was designed and fabricated which allowed to improve the operation conditions in time, frequency, temperature and selection of the grinding media and that allow the contamination decrease of the compounds. By means of this method of mechanical alloying new metallic compounds can be produced, starting from elemental powders, with fine and controlled microstructures. These compounds prepared by this method are going to be used as materials for the hydrogen storage. (Author)

  6. Transmutation of alloys in MFE facilities as calculated by REAC (a computer code system for activation and transmutation)

    International Nuclear Information System (INIS)

    A computer code system for fast calculation of activation and transmutation has been developed. The system consists of a driver code, cross-section libraries, flux libraries, a material library, and a decay library. The code is used to predict transmutations in a Ti-modified 316 stainless steel, a commercial ferritic alloy (HT9), and a V-15%Cr-5%Ti alloy in various magnetic fusion energy (MFE) test facilities and conceptual reactors

  7. General laws of the effect of hydrogen on the crystallization of amorphous alloys based on the quasi-binary TiNi-TiCu system

    Science.gov (United States)

    Spivak, L. V.; Shelyakov, A. V.; Shchepina, N. E.

    2014-02-01

    The crystallization processes that occur during heating of hydrogen-containing melt-quenched alloys based on the quasi-binary TiNi-TiCu system alloyed with aluminum, iron, hafnium, and zirconium are studied by high-resolution differential scanning calorimetry. The general laws of the transition of the hydrogen-containing alloys from an amorphous into a crystalline state are determined.

  8. Direct Measurement of the Metastable Liquid Miscibility Gap in Fe-Co-Cu Ternary Alloy System

    Institute of Scientific and Technical Information of China (English)

    CAO Chong-De; Georg P.G(O)RLER

    2005-01-01

    @@ The metastable liquid-liquid phase separation in undercooled Fe-Co-Cu ternary alloy melts (XCu = 0.10-0.84;XCo:XFe = 1:3,1:1 and 3:1) is investigated by differential thermal analysis in combination with glass fluxing technique. In almost every case, the undercooling of the homogeneous alloy melt was sufficient to reach the boundary line of the submerged miscibility gap. The differential-thermal-analysis signals indicate that this separation into a (Fe, Co)-rich liquid phase L1 and a Cu-rich liquid L2 is exothermic and proceeds until the rapid solidification of the L1 phase occurs. At a given Cu concentration and with the increase of Co content, the phase separation temperatures decrease monotonically between the corresponding values of the boundary systems Fe-Cu and Co-Cu. The boundary lines of the miscibility gap, which are determined for the three quasi-binary cross-sections of the (Fe, Co)-Cu alloy system, show remarkably flat domes. The occurrence of the liquid phase separation shows an evident influence on the subsequent γ-Fe(Co, Cu)→α-Fe(Co, Cu) solid phase transformation.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-07-29

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

  10. Chemical equilibrium studies of tritium--lithium and tritium--lithium alloy systems

    International Nuclear Information System (INIS)

    In deuterium-tritium fusion reactors currently under design, the production of tritium is accomplished by utilizing a lithium-bearing blanket. Lithium metal is presently the leading candidate for the blanket material, although molten Li2BeF4, solid Li--Al (50-50 at. percent) alloy and other lithium-containing materials are distinct possibilities. This paper summarizes progress of ongoing studies of the thermodynamics of some of these lithium containing systems. The individual solubilities of hydrogen, deuterium, and tritium in lithium as a function of temperature (700 to 10000C) and pressure are presented. Recent work with the solid alloy Li--Al (50-50 at. percent) has shown that the tritium solubility between 400 and 6000C is low. When the tritium pressure was between 0.14 and 0.52 torr, the Li--Al samples contained only 1 to 4 ppm tritium

  11. Selection of a Microbiological Corrosion System for Studying Effects on Structural Aluminum Alloys.

    Science.gov (United States)

    Hedrick, H G; Miller, C E; Halkias, J E; Hildebrand, J E

    1964-05-01

    Two laboratory methods, a metal-strip test and a tank test, were evaluated as microbiological corrosion systems for producing corroded test specimens on a structural aluminum alloy. The results show that corrosion of the test alloy occurred best in the metal-strip test in a deionized water-fuel medium inoculated with a mixture of microorganisms under aerated conditions. The metal-strip test was more successful for producing large numbers of corroded test specimens and proved more economical than the tank-type test, since less structural material is needed to obtain a specimen with sufficient corrosion areas, and since the corrosion can more easily be restricted by maskants to certain areas for specific test purposes. PMID:16349646

  12. Effect of substitutional element in the microstructure and hardness of Ti-Zr system alloys used as biomaterials

    International Nuclear Information System (INIS)

    New titanium alloys had been developed with the aim of obtaining materials with improved properties for application as biomaterial, and alloys of the Ti-Zr system are among those most promising. The objective of this study is to analyze the influence of the zirconium concentration on microstructure and hardness of the Ti-5Zr, Ti-10Zr and Ti-15Zr alloys. After arc-melting melting, the samples were analyzed by chemical and gas composition, and characterized by density measurements, optical microscopy, x-ray diffraction and hardness. The results showed a microstructure formed by alpha phase (hexagonal close-packed structure) and increased of hardness. (author)

  13. Experimental Study of the Sb-Sn-Zn Alloy System

    Czech Academy of Sciences Publication Activity Database

    Zobač, O.; Sopoušek, J.; Buršík, Jiří; Zemanová, Adéla; Roupcová, Pavla

    2014-01-01

    Roč. 45, č. 3 (2014), s. 1181-1188. ISSN 1073-5623 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : Sb-Sn-Zn system * thermal analysis * CALPHAD method Subject RIV: BJ - Thermodynamics Impact factor: 1.730, year: 2014

  14. Ruthenium-manganese / Alumina supported bimetallic alloy system for car exhaust pollution control

    International Nuclear Information System (INIS)

    The main source of carbon monoxide emission onto the atmosphere causing pollution and environmental hazards comes from car exhaust. A bimetallic alloy system Ru:Mn supported on high surface area, alumina oxide support was developed using CO impregnation method. This system was subjected to alternate reduction and oxidation at high temperature. The purpose of this treatment was two folds. 1). To produce a large surface area for the CO adsorption emitted from car exhaust. 2). To produce potentially important saturate/ unsaturated hydrocarbon products by the hydrogenation of the deposited carbon. The prepared system was characterised using bet surface area measurement, XPS, SSIMS, TEM, EELS and CO chemisorption. After adsorption of CO, the pellets were removed and the system was subjected to CO-hydrogenation. The data indicates that CO coming from car exhaust in linearly adsorbed on the surface and the subject treatment of the system at high temperature after hydrogenation produces more unsaturated hydrocarbon products due to presence of higher oxidation states of the metal used. The alloy system was finally recovered for further use. A high surface area pellets were finally prepared and arrangements are in progress to test the prepared system for its life and working. (author)

  15. Extended solid solubility of a Co-Cr system by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Betancourt-Cantera, J.A. [Area Academica de Ciencias de la Tierra y Materiales, UAEH Carr. Pachuca-Tulancingo Km. 4.5, Pachuca, Hidalgo 42184 (Mexico); Sanchez-De Jesus, F., E-mail: fsanchez@uaeh.edu.mx [Area Academica de Ciencias de la Tierra y Materiales, UAEH Carr. Pachuca-Tulancingo Km. 4.5, Pachuca, Hidalgo 42184 (Mexico); Torres-Villasenor, G. [Instituto de Investigaciones en Materiales-UNAM, Apdo. Postal 70-360, 04510 Mexico, DF (Mexico); Bolarin-Miro, A.M. [Area Academica de Ciencias de la Tierra y Materiales, UAEH Carr. Pachuca-Tulancingo Km. 4.5, Pachuca, Hidalgo 42184 (Mexico); Cortes-Escobedo, C.A. [Centro de Investigacion e Innovacion Tecnologica del IPN Cda. CECATI S/N, Col. Sta. Catarina, Azcapotzalco, 02250 Mexico, DF (Mexico)

    2012-07-15

    Highlights: Black-Right-Pointing-Pointer Solubility of the Co-Cr system is modified by means of Mechanical Alloying (MA). Black-Right-Pointing-Pointer MA induces the formation of new solid solutions of Co-Cr system in non-equilibrium. Black-Right-Pointing-Pointer MA promote the formation of metastable Co-Cr phases with greater solubility. - Abstract: Mechanical alloying, MA, has been successfully used to extend the limits of solid solubility in many commercially important metallic systems. The aim of this work is to demonstrate that MA modifies the solid solubility of the Co-Cr system. Co and Cr elemental powders were used as precursors and mixed in an adequate weight ratio to obtain Co{sub 100-x}Cr{sub x} (0 {<=} x {<=} 100, {Delta}x = 10) to study the effect of mechanical processing in the solubility of the Co-Cr system. Processing was carried out at room temperature in a shaker mixer mill using vials and balls of hardened steel as milling media with a ball:powder weight ratio of 10:1. Crystalline structure characterization of the milled powders was conducted using X-ray diffraction, and phase transformations as a function of composition were analyzed. Thermal analysis confirmed structural changes occurred in the mechanically alloyed powders. The evolution of the phase transformations with composition is reported for each composition. The results showed that after high energy ball milling for 7 h, the solid solubility between Co and Cr could be evidently extended, despite the low solid solubility at the equilibrium conditions of this system. Additionally, the micrographs of the milled powders showed that increasing composition of chromium changes the shape and size of the particles while simultaneously reducing their agglomeration; this effect is possibly attributed to the brittleness of elemental chrome.

  16. Mechanical Properties of Magnesium-Rare Earth Alloy Systems: A Review

    Directory of Open Access Journals (Sweden)

    Sravya Tekumalla

    2014-12-01

    Full Text Available Magnesium-rare earth based alloys are increasingly being investigated due to the formation of highly stable strengthening phases, activation of additional deformation modes and improvement in mechanical properties. Several investigations have been done to study the effect of rare earths when they are alloyed to pure magnesium and other Mg alloys. In this review, the mechanical properties of the previously investigated different magnesium-rare earth based binary alloys, ternary alloys and other higher alloys with more than three alloying elements are presented.

  17. Analysis of causes inappropriate registrations in the computer system control high-grade alloys casting

    OpenAIRE

    B. Pisarek

    2010-01-01

    In the aim of improvement of the process of the registration of characteristics TDA (thermal and derivative analysis) in the industry as and the Process Failure Mode and Effects Analysis was carry out on investigative stands using the Computer System of Quality Control Alloys (CSQCA). The necessity of the operators of the system, the workers of section QC and the managers of production in the aim of realiza-tion of and emphasising the meaning of the warning of the methodic of measurements usi...

  18. Phase equilibria in the Ni-Co-Ga alloy system

    International Nuclear Information System (INIS)

    Phase equilibria among the α (A1), α' (L12), β (B2), δ (Ni5Ga3) and ε (Ni13Ga9) phases at elevated temperatures and the existing composition region of the martensite phase at room temperature in the Ni-Co side of the Ni-Co-Ga system were examined by electron probe microanalysis (EPMA) using diffusion triples which were fabricated by two-step diffusion coupling. It was confirmed that single-phase regions of the α, α' and β phases at 700 and 1000 deg. C exist in a wide composition range parallel to Ni-Co section and that the existing region of the martensite phase at room temperature is also located over a wide range in the β phase along the β + α (or α') two-phase region

  19. Investigation of austenitic alloys for advanced heat recovery and hot gas cleanup systems

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, R.W.; Ren, W.

    1996-06-01

    The objective of the research is to provide databases and design criteria to assist in the selection of optimum alloys for construction of components needed to contain process streams in advanced heat recovery and hot-gas cleanup systems. Typical components include: steam line piping and superheater tubing for low emission boilers (600 to 700{degrees}C), heat exchanger tubing for advanced steam cycles and topping cycle systems (650 to 800{degrees}C), foil materials for recuperators, on advanced turbine systems (700 to 750{degrees}C), and tubesheets for barrier filters, liners for piping, cyclones, and blowback system tubing for hot-gas cleanup systems (850 to 1000{degrees}C). The materials being examined fall into several classes, depending on which of the advanced heat recovery concepts is of concern. These classes include martensitic steels for service to 650{degrees}C, lean stainless steels and modified 25Cr-30Ni steels for service to 700{degrees}C, modified 25Cr-20Ni steels for service to 900{degrees}C, and high Ni-Cr-Fe or Ni-Cr-Co-Fe alloys for service to 1000{degrees}C.

  20. Phase equilibria in the Ni-Fe-Ga alloy system

    International Nuclear Information System (INIS)

    The phase equilibria, A2/B2 and B2/L21 (or D03) order-disorder transitions and martensitic transformation on the Ni-Fe side of the Ni-Fe-Ga system were examined by electron probe microanalysis (EPMA) and differential scanning calorimetric (DSC) measurement. The equilibrium compositions of interrelations mainly among the α (A2), β (B2), β' (L21 or D03), γ (A1) and γ' (L12) phases were determined using diffusion triples which were fabricated by two-step diffusion coupling. It was confirmed that a bcc single-phase region composed of α, β and β' at 850-1000 deg. C exists in a wide composition range and that the critical temperature of the B2/L21 order-disorder transformation in the Fe3Ga-Ni3Ga pseudo-binary section gradually increases with increasing Ni content. The existing composition region of the martensite phase at room temperature was also determined by the diffusion triple method

  1. Wettability in the liquid Cu-Ag alloy – fireproof material – gas phase system

    Directory of Open Access Journals (Sweden)

    G. Siwiec

    2013-07-01

    Full Text Available In the present paper, results of wettability studies on the liquid metal – fireproof material – gas phase system using copper and Cu-Ag alloys as well as typical fireproof materials, i.e. aluminium oxide, magnesium oxide and graphite, are presented. Contact angle measurements were conducted at 1 373–1 573 K by means of a high-temperature microscope coupled with a camera and a computer equipped with a program for recording and analysing images. For the measurements, the sessile drop method was used.

  2. Calculation of the self-formation driving force for composite microstructure in liquid immiscible alloy system

    Institute of Scientific and Technical Information of China (English)

    LIU Xingjun; WANG Cuiping; Ikuo OHNUMA; Ryosuke KAINUMA; Kiyohito ISHIDA; CHEN Xiaohu

    2005-01-01

    Using Becker's method, we calculate the interfacial energy between two liquid phases in an immiscible system. Based on the Gibbs-Thomson equation, the force acting on the droplet towards the thermal center can be obtained by integrating the interfacial energy between the droplet and matrix liquid phase, which is related to both the radius of a droplet and the temperature gradient. In addition, the forces of gravitation and buoyancy also act on the droplet. The calculated results indicate that the resultant for these forces together mainly decides the microstructure morphology of the solidified alloy. The calculated results are in good agreement with the corresponding experimental results.

  3. 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.

  4. 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.

  5. Neutron scattering measurements a useful alloy development tool for the new generation high temperature alloys based Co-Re system

    Czech Academy of Sciences Publication Activity Database

    Mukherji, D.; Wehr, J.; Strunz, Pavel; Gilles, R.; Hofmann, M.; Hoelzel, M.; Roesler, J.

    München : Technische Universität München, 2012 - (Carsughi, F.; Lommatzsch, I.; Neuhaus, J.). s. 34-34 [4th User Meeting at the FRM II. 23.03.2012-23.03.2012, Garching bei München] Institutional support: RVO:61389005 Keywords : Co-Re based alloys * neutron scattering * high temeperature Subject RIV: BM - Solid Matter Physics ; Magnetism http://cdn.frm2.tum.de/fileadmin/stuff/ information /UserOffice/UM2012_Booklet_lr.pdf

  6. Comparison of Shear Bond Strengths of three resin systems for a Base Metal Alloy bonded to

    Directory of Open Access Journals (Sweden)

    Jlali H

    1999-12-01

    Full Text Available Resin-bonded fixed partial dentures (F.P.D can be used for conservative treatment of partially edentulous"npatients. There are numerous studies regarding the strength of resin composite bond to base meta! alloys. Shear bond"nstrength of three resin systems were invistigated. In this study these systems consisted of: Panavia Ex, Mirage FLC and"nMarathon V. Thirty base metal specimens were prepared from rexillium III alloy and divided into three groups. Then each"ngroup was bonded to enamel of human extracted molar teeth with these systems. All of specimens were stored in water at"n37ac for 48 hours. A shear force was applied to each specimen by the instron universal testing machine. A statistical"nevaluation of the data using one-way analysis of variance showed that there was highly significant difference (P<0.01"nbetween the bond strengths of these three groups."nThe base metal specimens bonded with panavia Ex luting agent, exhibited the highest mean bond strength. Shear bond"nstrength of the specimens bonded to enamel with Mirage F1C showed lower bond strenght than panavia EX. However, the"nlowest bond strength was obtained by the specimens bonded with Marathon V.

  7. Comparison of the Effect of Different Ceramic Alloys and Porcelain Systems upon the Color of Metal–Ceramic Restorations: An In Vitro Study

    OpenAIRE

    Anitha, K. V.; Dhanraj, M.; Haribabu, R.

    2013-01-01

    The exact replication of natural tooth color in a metal ceramic restoration is a challenging fact as its affected by enumerable factors. Research revealing the influence of base metal alloys with different porcelain systems on the color of the restorations have shown minimal interest. The aim of the study was to evaluate the optical influence of different alloys (mainly base metal) and ceramic systems affecting the final color of metal–ceramic restorations. Four commercial ceramic alloys, two...

  8. Corrosion of copper-alloy tubes in the NPP cooling systems

    International Nuclear Information System (INIS)

    Factors efficiency on leaks in the NPP power unit steam turbine condensers are analyzed. Causes of corrosion - erosion wear of copper-alloy tubes are considered. A model for calculation of copper and copper-nickel alloy corrosion is proposed

  9. 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...

  10. Structure of alloys and phase equilibrium diagram in Zr-Ru-Ir system

    International Nuclear Information System (INIS)

    A projection of solidus surface is plotted for the partial Ru-ZrRu-ZrIr-I) system. It is shown that ternary compounds are not formed in this system. Isostrucutural ZeRu and ZrIr phases form a continuous series of solid solutions. A high reciprocal solubility of ruthenium and iridium is observed both in primary solid solutions and in intermediate ZrRu2, ZpIr2 and ZrIr3 phase (from 0.29 to 0.5%). Four triphase fields exist at subsolidus temperatures: + + 3 >, 3 > + 2 > + 2 >, 2 > + 2 > + Zr(Ru, Ir) and + 3 > + 2 > as well as nine duel phases corresponding to them. Temperatures of the melting start for the Ru-ZrRu-ZrIA-Ir system alloys decrease to the Zr-Ru side of the concentration triangle

  11. Critical issues in the use of metals and alloys in sulphur-containing aqueous systems

    Energy Technology Data Exchange (ETDEWEB)

    Macdonald, D.D.

    1992-12-31

    Sulphur-containing aqueous fluids are amongst the most corrosive environments experienced in industrial and natural systems. The high corrosivity is due principally to the wide range of oxidation states that sulphur may exist in within the thermodynamic stability domain of water, as well as to the high lability of many sulphur species, such as the polythionic acids and polysulfides. Additionally, sulphur, along with arsenic, antimony, and mercury, effectively promotes the entry of hydrogen into metal and alloy matrices, thereby leading to hydrogen damage and hydrogen embrittlement. In this paper, the chemistry of sulphur species in aqueous solutions and of the various iron sulphides is reviewed with emphasis on illustrating the diverse nature of metal/sulphur interactions. Finally, we identify a number of critical issues that need to be resolved to greatly improve our understanding of the chemistry of sulphur-containing systems and to improve our ability to predict the form and extent of corrosion in geochemical and geoenergy systems.

  12. Critical issues in the use of metals and alloys in sulphur-containing aqueous systems

    Energy Technology Data Exchange (ETDEWEB)

    Macdonald, D.D.

    1992-01-01

    Sulphur-containing aqueous fluids are amongst the most corrosive environments experienced in industrial and natural systems. The high corrosivity is due principally to the wide range of oxidation states that sulphur may exist in within the thermodynamic stability domain of water, as well as to the high lability of many sulphur species, such as the polythionic acids and polysulfides. Additionally, sulphur, along with arsenic, antimony, and mercury, effectively promotes the entry of hydrogen into metal and alloy matrices, thereby leading to hydrogen damage and hydrogen embrittlement. In this paper, the chemistry of sulphur species in aqueous solutions and of the various iron sulphides is reviewed with emphasis on illustrating the diverse nature of metal/sulphur interactions. Finally, we identify a number of critical issues that need to be resolved to greatly improve our understanding of the chemistry of sulphur-containing systems and to improve our ability to predict the form and extent of corrosion in geochemical and geoenergy systems.

  13. Exploration of CIGAS Alloy System for Thin-Film Photovoltaics on Novel Lightweight and Flexible Substrates

    Science.gov (United States)

    Woods, Lawrence M.; Kalla, Ajay; Ribelin, Rosine

    2007-01-01

    Thin-film photovoltaics (TFPV) on lightweight and flexible substrates offer the potential for very high solar array specific power (W/kg). ITN Energy Systems, Inc. (ITN) is developing flexible TFPV blanket technology that has potential for specific power greater than 2000 W/kg (including space coatings) that could result in solar array specific power between 150 and 500 W/kg, depending on array size, when mated with mechanical support structures specifically designed to take advantage of the lightweight and flexible substrates.(1) This level of specific power would far exceed the current state of the art for spacecraft PV power generation, and meet the needs for future spacecraft missions.(2) Furthermore the high specific power would also enable unmanned aircraft applications and balloon or high-altitude airship (HAA) applications, in addition to modular and quick deploying tents for surface assets or lunar base power, as a result of the high power density (W/sq m) and ability to be integrated into the balloon, HAA or tent fabric. ITN plans to achieve the high specific power by developing single-junction and two-terminal monolithic tandem-junction PV cells using thin-films of high-efficiency and radiation resistant CuInSe2 (CIS) partnered with bandgap-tunable CIS-alloys with Ga (CIGS) or Al (CIAS) on novel lightweight and flexible substrates. Of the various thin-film technologies, single-junction and radiation resistant CIS and associated alloys with gallium, aluminum and sulfur have achieved the highest levels of TFPV device performance, with the best efficiency reaching 19.5% under AM1.5 illumination conditions and on thick glass substrates.(3) Thus, it is anticipated that single- and tandem-junction devices with flexible substrates and based on CIS and related alloys will achieve the highest levels of thin-film space and HAA solar array performance.

  14. An innovative ultra-capacitor driven shape memory alloy actuator with an embedded control system

    International Nuclear Information System (INIS)

    In this paper, an innovative ultra-capacitor driven shape memory alloy (SMA) actuator with an embedded control system is proposed targeting high power high-duty cycle SMA applications. The ultra-capacitor, which is capable of delivering massive amounts of instantaneous current in a compact dimension for high power applications, is chosen as the main component of the power supply. A specialized embedded system is designed from the ground up to control the ultra-capacitor driven SMA system. The control of the ultra-capacitor driven SMA is different from that of a regular constant voltage powered SMA system in that the energy and the voltage of the ultra-capacitor decrease as the system load increases. The embedded control system is also different from a computer-based control system in that it has limited computational power, and the control algorithm has to be designed to be simple while effective so that it can fit into the embedded system environment. The problem of a variable voltage power source induced by the use of the ultra-capacitor is solved by using a fuzzy PID (proportional integral and derivative) control. The method of using an ultra-capacitor to drive SMA actuators enabled SMA as a good candidate for high power high-duty cycle applications. The proposed embedded control system provides a good and ready-to-use solution for SMA high power applications. (paper)

  15. Development of Advanced Wear and Corrosion Resistant Systems Through Laser Surface Alloying and Materials Simulations

    Energy Technology Data Exchange (ETDEWEB)

    R. P. Martukanitz and S. Babu

    2007-05-03

    precipitation of titanium carbonitrides during laser surface alloying provided there was sufficient amount of dissolved titanium, carbon, and nitrogen in the liquid steel. This was confirmed experimentally by using a powder mixture of 431-martensitic steel, titanium carbide powder, and nitrogen shielding, during laser deposition to produce deposits exhibiting relatively high hardness (average surface hardness of 724 HV). The same approach was extended to direct diode laser processing and similar microstructures were attained. The above analysis was extended to develop an in-situ precipitation of Ti(CN) during laser deposition. The Ti addition was achieving by mixing the 431 martensitic steel powders with ferro-titanium. The dissolution of nitrogen was achieved by using 100% nitrogen shielding gas, which was indicated by thermodynamic analysis. Demonstrations were also conducted utilizing the tools developed during the program and resulted in several viable composite coating systems being identified. This included the use of TiC and ferro-titanium in martensitic-grade stainless steel matrix material with and without the use of active N2 shielding gas, WC hard particles in a martensitic-grade stainless steel matrix material, WC and BN in a nickel-based matrix material, and WC in highly alloyed iron-based matrix. Although these demonstrations indicated the potential of forming composite coatings, in certain instances, the intended industrial applications involved unique requirements, such as coating of internal surfaces, which hindered the full development of the improved coating technology. However, it is believed that the addition of common hard particles, such as WC or TiC, to matrix material representing martensitic grades of stainless steel offer opportunities for improved performance at relatively low material cost.

  16. Metastable phases in the aluminum-germanium alloy system: Synthesis by mechanical alloying and pressure induced transformations

    Energy Technology Data Exchange (ETDEWEB)

    Yvon, P.

    1994-01-01

    Al and Ge form a simple equilibrium eutectic with limited mutual solubility and no intermetallic intermediate phases. We used a regular solution approach to model effects of pressure on Al-Ge. Effects of pressure are to extend solubility of Ge in Al, to displace the eutectic composition towards the Ge rich side, and to slightly decrease the eutectic temperature. We designed thermobaric treatments to induce crystal-to-glass transformations in fine grain mixtures of Al and Ge. We used Merrill-Bassett diamond anvil cells to perform experiments at high pressures. We built an x-ray apparatus to determine the structure of alloys at pressure and from cryogenic temperatures to 400C. Two-phase Al-Ge samples with fine microstructures were prepared by splat-quenching and mechanical alloying. We observed a crystal-to-glass transformation at about 80 kbar. The amorphous phase formed was metastable at ambient temperature after pressure release. This was confirmed by TEM. The amorphous phase obtained by pressurization was found to have a liquid-like structure and was metallic. In the TEM samples we also observed the presence of a second amorphous phase formed upon release of the pressure. This second phase had a tetrahedrally-bonded continuous random network structure, similar to that of semi-conducting amorphous germanium.

  17. Creeping of ZrC-ZrB2 and TiC-TiB2 system alloys at compression

    International Nuclear Information System (INIS)

    The paper is concerned with regularities of high-temperature (1700-2420 deg C) creeping in high-dense fine-grained sintered compositions of the ZrC-ZrB2 and TiC-TiB2 systems. Extremum creeping rate epsilon is determined for alloys with the most developed grain interface (V1:V2=1:1) which for the mentioned system coincides with eutectic compositions. It is shown that nonadditive changes in the creeping rate and a considerable increase in the absolute value of deformation (not less than 30%) in compositions with extremum epsilon as compared with that in individual alloys (5-6%) testify to superplasticity effects in alloys of the mentioned systems. An effect of stress (5-30 MPa) on the epsilon=f(σsup(n)) dependence is studied. It is determined that in alloys of the ZrC-ZrB2 system n>=1 in the TiC-TiB2 system - n>=1.5. It is shown that participation of threshold mechanisms in the mainly intergranular deformation in the TiC-TiB2 system may be related to a possibility for coherent grain boundaries to arise during sintering of disperse powders (d<<0.5 μm)

  18. Interactions between TiAl alloy and AZC/AMT binder systems in investment casting

    Directory of Open Access Journals (Sweden)

    Yi Jia

    2015-11-01

    Full Text Available In this work, two kinds of binders, Ammonium Zirconium Carbonate (AZC and Ammonium Metatungstate (AMT hydrate, and three kinds of powders (ZrO2, Al2O3 and Y2O3 were mixed to fabricate six kinds of face coating systems. The thermal behaviors of the AZC and AMT dried binders were investigated by TG-DTA, and the phase transformation of the two binders was determined by XRD. Monoclinic ZrO2 phase was formed from AZC at 620 °C and WO3 at 700 °C, and the phase transformation was completed at lower than 1000 °C in both binders, and therefore, the sintering temperature for the molds was selected at 950 °C. The interaction between the ceramic molds with different face coatings and the Ti-48Al-2Cr-2Nb alloy during investment casting was studied. Results showed no α-case reaction in the TiAl-mold reaction, and the AMT + Y2O3 face coating appeared to be the best choice for investment casting of TiAl alloys under the experimental conditions.

  19. Gating System Design for Casting thin Aluminium Alloy (Al-Si Plates

    Directory of Open Access Journals (Sweden)

    Victor ANJO

    2013-11-01

    Full Text Available The main problems caused by improper gating are entrained aluminium oxide films, cuts and washes, low casting yield and entrapped gas. This study describes the design of a gating system to produce thin Aluminium cast alloy plates of different sizes and thicknesses of 4mm, 6mm, 8mm, and 10mm using the non-pressurized gating with ratio of 1:4:4 and green sand moulding technique. The gating design was based on the laws of fluid mechanics and empirical rules of gating for non ferrous metals. The equipments used for this experiment includes; a coal fired crucible furnace and an X-Ray machine. Materials used include; silica sand, clay, wood, glue and Aluminium alloy scraps. The experimental procedure involved: the gating design calculations, construction of wooden pattern and gating; using the wooden pattern and gating to produce the mould cavities and gating; melting, melt treatment and pouring of melt in the sand mould to produce the casting. The plate castings after removal from mould were visually examined for surface defects and after fettling and cleaning X-Ray radiography was used to find the internal soundness of the castings. From the results obtained in the experiment, it was found that there were no internal defects and quality castings were produced.

  20. An innovative seismic bracing system based on a superelastic shape memory alloy ring

    Science.gov (United States)

    Gao, Nan; Jeon, Jong-Su; Hodgson, Darel E.; DesRoches, Reginald

    2016-05-01

    Shape memory alloys (SMAs) have great potential in seismic applications because of their remarkable superelasticity. Seismic bracing systems based on SMAs can mitigate the damage caused by earthquakes. The current study investigates a bracing system based on an SMA ring which is capable of both re-centering and energy dissipation. This lateral force resisting system is a cross-braced system consisting of an SMA ring and four tension-only cable assemblies, which can be applied to both new construction and seismic retrofit. The performance of this bracing system is examined through a quasi-static cyclic loading test and finite element (FE) analysis. This paper describes the experimental design in detail, discusses the experimental results, compares the performance with other bracing systems based on SMAs, and presents an Abaqus FE model calibrated on the basis of experimental results to simulate the superelastic behavior of the SMA ring. The experimental results indicate that the seismic performance of this system is promising in terms of damping and re-centering. The FE model can be used in the simulation of building structures using the proposed bracing system.

  1. Seismic assessment of bridge structures isolated by a shape memory alloy/rubber-based isolation system

    International Nuclear Information System (INIS)

    This paper explores the effectiveness of shape memory alloy (SMA)/rubber-based isolation systems for seismic protection of bridges against near-field earthquakes by performing a sensitivity analysis. The isolation system considered in this study consists of a laminated rubber bearing, which provides lateral flexibility while supplying high vertical load-carrying capacity, and an auxiliary device made of multiple loops of SMA wires. The SMA device offers additional energy dissipating and re-centering capability. A three-span continuous bridge is modeled with the SMA/rubber-based (SRB) isolation system. Numerical simulations of the bridge are conducted for various near-field ground motions that are spectrally matched to a target design spectrum. The normalized forward transformation strength, forward transformation displacement and pre-strain level of the SMA device, ambient temperature and the lateral stiffness of the rubber bearings are selected as parameters of the sensitivity study. The variation of the seismic response of the bridge with the considered parameters is assessed. Also, the performance of the SRB isolation system with optimal design parameters is compared with an SMA-based sliding isolation system. The results indicate that the SRB isolation system can successfully reduce the seismic response of highway bridges; however, a smart isolation system that combines sliding bearings together with an SMA device is more efficient than the SRB isolation system

  2. Analysis of causes inappropriate registrations in the computer system control high-grade alloys casting

    Directory of Open Access Journals (Sweden)

    B. Pisarek

    2010-10-01

    Full Text Available In the aim of improvement of the process of the registration of characteristics TDA (thermal and derivative analysis in the industry as and the Process Failure Mode and Effects Analysis was carry out on investigative stands using the Computer System of Quality Control Alloys (CSQCA. The necessity of the operators of the system, the workers of section QC and the managers of production in the aim of realiza-tion of and emphasising the meaning of the warning of the methodic of measurements using TDA periodical training results from intro-duced analyses. The mechanization and automation (in well-founded cases e.g.: in the process of pressure die casting the station of cast the probe, the repeatability of conditions can guarantee cast the probe ATD (i.e. the speeds cast the probe, proper heating of pouring cup dosing metal, the quantities of the metal poured to probe. Proper designing the Station of Cast TDA Probe isolates the tripod and probe itself from man-made interference generated by the closest surroundings and the more frequent measurements of the temperature of the liquid metal in landle, they make possible avoidance of the basic causes of incorrect the TDA registrations. Work this makes up training materials for the operators of the system and the managers is responsible for the control of the quality of alloys the TDA method in the foundry. The introduced list of the most frequent irregularities, during the registration the TDA, it will make possible the quick identification of their causes and undertaking of suitable preventive workings to the operators of the system.

  3. An experimental search for high ZT semiconductors: A survey of the preparation and properties of several alloy systems

    International Nuclear Information System (INIS)

    A survey was conducted of several alloy systems identified as having certain properties thought to be desirable in high figure-of-merit thermoelectric materials. The systems examined include the cerium and lanthanum borocarbides, yttrium nitrides, osmium silicides, and titanium sulfides. Various approaches to the preparation of these alloy systems were explored including vapor transport, arc melting, and mechanical alloying. Among these systems, the borocarbides were found to exhibit p-type conductivity but generally suffered from relatively high carrier concentrations (on the order of 1021/cm3) and low mobilities (≤10 cm2/V-s). Both carbon and sulfur dopants produced the highest figure of merit (0.13x10-3/ degree C) in the yttrium nitride system at room temperature. Excess silicon was observed to increase carrier concentration and Hall mobility in osmium disilicide while additions of chromium were observed to stabilize the OsSi2 crystal structure. Electrical power factors comparable to state of the art silicon-germanium alloys were achieved in titanium disulfide, however, the electrical transport properties were found to be critically dependent upon the amount of excess Ti in Ti1+xS2. copyright 1995 American Institute of Physics

  4. Solid State Joining of High Temperature Alloy Tubes for USC and Heat-Exchanger Systems

    Energy Technology Data Exchange (ETDEWEB)

    Bimal Kad

    2011-12-31

    The principal objective of this project was to develop materials enabling joining technologies for use in forward looking heat-exchanger fabrication in Brayton cycle HIPPS, IGCC, FutureGen concepts capable of operating at temperatures in excess of 1000{degree}C as well as conventional technology upgrades via Ultra Super-Critical (USC) Rankine-cycle boilers capable of operating at 760{degree}C (1400F)/38.5MPa (5500psi) steam, while still using coal as the principal fossil fuel. The underlying mission in Rankine, Brayton or Brayton-Rankine, or IGCC combined cycle heat engine is a steady quest to improving operating efficiency while mitigating global environmental concerns. There has been a progressive move to higher overall cycle efficiencies, and in the case of fossil fuels this has accelerated recently in part because of concerns about greenhouse gas emissions, notably CO{sub 2}. For a heat engine, the overall efficiency is closely related to the difference between the highest temperature in the cycle and the lowest temperature. In most cases, efficiency gains are prompted by an increase in the high temperature, and this in turn has led to increasing demands on the materials of construction used in the high temperature end of the systems. Our migration to new advanced Ni-base and Oxide Dispersion Strengthened (ODS) alloys poses significant fabrication challenges, as these materials are not readily weldable or the weld performs poorly in the high temperature creep regime. Thus the joining challenge is two-fold to a) devise appropriate joining methodologies for similar/dissimilar Ni-base and ODS alloys while b) preserving the near baseline creep performance in the welded region. Our program focus is on solid state joining of similar and dissimilar metals/alloys for heat exchanger components currently under consideration for the USC, HIPPS and IGCC power systems. The emphasis is to manipulate the joining methods and variables available to optimize joint creep

  5. Microstructural studies on variation of defect parameters in Zr-Sn alloys and their transition with interchange of solvent and solute in Zr-Ti and Ti-Zr alloy systems by modified Rietveld method and Warren-Averbach method

    International Nuclear Information System (INIS)

    The effects of deformation and the transition of microstructural defect states with the interchange of solvent and solute in Ti-Zr and Zr-Ti alloys of six different compositions and Zr-Sn alloys in three different compositions have been investigated by x-ray diffraction line profile analysis. The detailed analysis of the x-ray powder diffraction line profiles was interpreted by Fourier line shape analysis using modified Rietveld method and Warren-Averbach method taking silicon as standard. Finally the microstructural parameters such as coherent domain size, microstrains within domains, faulting probability and dislocation density were evaluated from the analysis of x-ray powder diffraction data of Zr base Sn, Ti and Ti base Zr alloys by modified Rietveld powder structure refinement. This analysis confirms that the growth fault, β, is totally absent or negligibly present in Zr-Ti, Ti-Zr and Zr-Sn alloy systems, because the growth fault, β, has been observed to be either negative or very small for these alloy systems. This analysis also revealed that the deformation fault, α, has significant presence in titanium-base zirconium alloy systems but when zirconium content in the matrix goes on increasing beyond 50%, this faulting behaviour suffers a drastic transition and faulting tendency abruptly drops to a level of negligible presence or zero. This tendency has also been observed in Zr-Sn alloys signifying high stacking fault energy. Therefore, Zr and Zr-base alloys having high stacking fault energy can be used as hard alloys in nuclear technology at high temperature. (author)

  6. Microstructural studies on variation of defect parameters in Zr–Sn alloys and their transition with interchange of solvent and solute in Zr–Ti and Ti–Zr alloy systems by modified Rietveld method and Warren–Averbach method

    Indian Academy of Sciences (India)

    J Ghosh; S K Chattopadhyay; A K Meikap; S K Chatterjee

    2006-08-01

    The effects of deformation and the transition of microstructural defect states with the interchange of solvent and solute in Ti–Zr and Zr–Ti alloys of six different compositions and Zr–Sn alloys in three different compositions have been investigated by X-ray diffraction line profile analysis. The detailed analysis of the X-ray powder diffraction line profiles was interpreted by Fourier line shape analysis using modified Rietveld method and Warren–Averbach method taking silicon as standard. Finally the microstructural parameters such as coherent domain size, microstrains within domains, faulting probability and dislocation density were evaluated from the analysis of X-ray powder diffraction data of Zr base Sn, Ti and Ti base Zr alloys by modified Rietveld powder structure refinement. This analysis confirms that the growth fault, , is totally absent or negligibly present in Zr–Ti, Ti–Zr and Zr–Sn alloy systems, because the growth fault, , has been observed to be either negative or very small for these alloy systems. This analysis also revealed that the deformation fault, , has significant presence in titanium-base zirconium alloy systems but when zirconium content in the matrix goes on increasing beyond 50%, this faulting behaviour suffers a drastic transition and faulting tendency abruptly drops to a level of negligible presence or zero. This tendency has also been observed in Zr–Sn alloys signifying high stacking fault energy. Therefore, Zr and Zr-base alloys having high stacking fault energy can be used as hard alloys in nuclear technology at high temperature.

  7. Experience with the use of copper alloys in seawater systems in the Norwegian sector of the North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Johnsen, Roy [Norwegian University of Science and Technology, NO-7491 Trondheim (Norway)

    2004-07-01

    Offshore oil and gas has been produced on the Norwegian Continental Shelf (NCS) for nearly 30 years. Seawater has been used extensively as cooling medium and firewater. Copper alloys have been an alternative material both for piping and equipment like pumps, valves, heat exchangers and screens. In this presentation the experience from the use from different oil companies will be presented. The paper will also contain a discussion about the future for copper alloys in seawater systems. This part will be based on input and discussions with senior corrosion specialists in oil companies. (authors)

  8. Planning and Computerised Monitoring of an Experiment of Thermal Analysis of the Alloys in the Al-Cu-Si System

    Directory of Open Access Journals (Sweden)

    Florentina Cziple

    2007-10-01

    Full Text Available The paper presents an installation conceived for the automatic registration of the temperature in the thermal analysis, at the industrial and laboratory level, with application to the system of non-ferrous alloys Al-Cu-Si. The experiment performed on the above installation is compared to processes monitored through simulation with specialised software.

  9. Application of the cobalt based superalloy Haynes Alloy 25 (L605) in the fabrication of future radioisotope power systems

    International Nuclear Information System (INIS)

    The development of a new generation of radioisotope power systems is presently underway using a variety of innovative material selections. One of these materials is the cobalt based superalloy Haynes Alloy 25 (L605) (Haynes International, Inc., Kokomo, IN) which is being proposed as a structural member in the fabrication of Alkali Metal Thermal to Electrical Conversion (AMTEC) cells for space applications and other proposed heat source applications. Even though Haynes Alloy 25 has been previously used in several space power systems, the new power systems presently being developed will have some operational characteristics outside of the known design envelope. Therefore, the future application of these new power system technologies is dependent on determining many of the long term high-temperature physical and mechanical properties of the base-lined materials. The emphasis of this paper is on the determination of some of the high temperature mechanical properties (yield strength, ultimate tensile strength, and percent elongation) and the material compatibility characteristics of Haynes Alloy 25. Haynes Alloy 25 compatibility capsules were designed and tested to determine its high-temperature compatibility with various proposed AMTEC cell materials (nickel, rhodium, and molybdenum) being considered for future applications. The results of the studies and material recommendations will be discussed

  10. Putative quantum criticality in the (Cr90Ir10)100−yVy alloy system

    International Nuclear Information System (INIS)

    Quantum criticality (QC) in spin-density-wave antiferromagnetic Cr and Cr alloy systems is a topic of current interest. In the present study, V was used as a tuning parameter to drive the Néel transition temperature (TN) of the (Cr90Ir10)100−yVy alloy series with 0 ≤ y ≤ 14.3 to zero and search for effects of QC in the process. The magnetic properties and possible QC behaviour (QCB) in this alloy system were investigated through electrical resistivity (ρ), specific heat (Cp), and susceptibility (χ) measurements as a function of temperature (T), indicating that TN is suppressed to zero at a critical concentration yc ≈ 9. The Sommerfeld coefficient (γ) is considered a key indicator of QCB and a peak is observed in γ(y) at yc on decreasing y through this concentration, followed by a sharp decreasing trend. This behaviour is reminiscent of that observed for γ of the prototypical Cr100−xVx QC system and allows for the classification of yc in the (Cr90Ir10)100−yVy alloy system as a possible QC point

  11. The thermal field contactless monitoring system for welding and local heat treatment of the zirconium alloys tubes

    International Nuclear Information System (INIS)

    One of the most controllable parameters at welding and heat treatment of ring joints from zirconium alloys are distribution and gradual change of temperature field in treatment zone. The proposed system is firmware complex which allows to measure contactless temperature field according to its thermal radiation

  12. Phase composition and structure of NiAl base alloys of Ni-Al-Co-M systems where M-Ti, Zr, Hf, V, Nb, Ta, Cr, Mo

    International Nuclear Information System (INIS)

    A study was made into the effect of transition metals (0.27-23 at.% of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo) on phase composition and microstructure of (β + γ)-alloys of the Ni-Al-Co system. It is concluded that for designing heat resistant nickel base alloys with the density not exceeding 7.3 g/cm3 the two-phase (β + γ) alloys can be taken as a basis. In alloys of the (29-43) Ni-(20-25)Al-(32-34)Co compositions with 1-1.8 at%Mo, Ta, Nb or V the occurrence of gamma'-phase secondary precipitations is shown to be possible. Ti and Cr contents may reach 3 and 12 at.% respectively. Alloying elements promote an increase of main strengthening element (Co) content in β-phase and enhance heat resistance of Ni-Al-Co alloys. 3 refs.; 6 figs

  13. Coating system of hydrogen storage alloy powder slurry; Suiso kyuzo gokin funmatsu surari no tofu sochi

    Energy Technology Data Exchange (ETDEWEB)

    Furukawa, J.

    1995-03-31

    As the hydrogen storage alloy powder slurry has a high density and a high viscosity, it is necessary to apply a considerably high tension to the current collector sheet when the current collector sheet is continuously coated with the hydrogen storage alloy powder slurry. This invention provides a method of continuously coating the hydrogen storage alloy powder slurry on the running current collector sheet. In order to keep the viscosity of alloy powder slurry constant and to reduce the tension to be applied to the sheet during coating, a stirring jig is installed facing to the front surface and back surface of the current collector sheet and rotating in the sheet running direction and in the opposite direction. In this way, the thixotropic structure of the hydrogen storage alloy powder slurry is constantly broken, so that a gradual increase in viscosity does not take place. Resultingly, the homogeneous hydrogen storage alloy electrode can be continuously produced. 6 figs.

  14. The formation of quasicrystal phase in Al-Cu-Fe system by mechanical alloying

    Directory of Open Access Journals (Sweden)

    Dilermando Nagle Travessa

    2012-10-01

    Full Text Available In order to obtain quasicrystalline (QC phase by mechanical alloying (MA in the Al-Cu-Fe system, mixtures of elementary Al, Cu and Fe in the proportion of 65-20-15 (at. % were produced by high energy ball milling (HEBM. A very high energy type mill (spex and short milling times (up to 5 hours were employed. The resulting powders were characterized by X-ray diffraction (XRD, differential scanning calorimetry (DSC and scanning electron microscopy (SEM. QC phase was not directly formed by milling under the conditions employed in this work. However, phase transformations identified by DSC analysis reveals that annealing after HEBM possibly results in the formation of the ψ QC phase.

  15. Dezincification and Brass Lead Leaching in Premise Plumbing Systems: Effects of Alloy, Physical Conditions and Water Chemistry

    OpenAIRE

    Zhang, Yaofu

    2009-01-01

    Brass components are widely used in drinking water distribution systems as valves, faucets and other fixtures. They can be corroded by â dezincification,â which is the selective leaching of zinc from the alloy. Dezincification in potable water systems has important practical consequences that include clogged water lines, premature system failure and leaks, and release of contaminants such as lead. Brass failures attributed to dezincification are known to occur at least occasionally all ove...

  16. DENSITY-FUNCTIONAL STUDY OF Zr-BASED ACTINIDE ALLOYS: 2. U-Pu-Zr SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Landa, A; Soderlind, P; Turchi, P; Vitos, L; Ruban, A

    2009-02-09

    Density-functional theory, previously used to describe phase equilibria in the U-Zr alloys [1], is applied to study ground state properties of the bcc U-Pu-Zr solid solutions. Calculated heats of formation of the Pu-U and Pu-Zr alloys are in a good agreement with CALPHAD assessments. We found that account for spin-orbit coupling is important for successful description of Pu-containing alloys.

  17. Multistrand, Fast Reaction, Shape Memory Alloy System for Uninhabited Aerial Vehicle Flight Control

    Directory of Open Access Journals (Sweden)

    M. Brennison

    2012-01-01

    Full Text Available This paper details an investigation of shape memory alloy (SMA filaments which are used to drive a flight control system with precision control in a real flight environment. An antagonistic SMA actuator was developed with an integrated demodulator circuit from a JR NES 911 subscale UAV actuator. Most SMA actuator studies concentrate on modeling the open-loop characteristics of such a system with full actuator performance modeling. This paper is a bit different in that it is very practically oriented and centered on development of a flight-capable system which solves the most tricky, practical problems associated with using SMA filaments for aircraft flight control. By using well-tuned feedback loops, it is shown that intermediate SMA performance prediction is not appropriate for flight control system (FCS design. Rather, capturing the peak behavior is far more important, along with appropriate feedback loop design. To prove the system, an SMA actuator was designed and installed in the fuselage of a 2 m uninhabited aerial vehicle (UAV and used to control the rudder through slips and coordinated turns. The actuator was capable of 20 degrees of positive and negative deflection and was capable of 7.5 in-oz (5.29 N cm of torque at a bandwidth of 2.8 Hz.

  18. Novel Concepts for Damage-Resistant Alloys in Next Generation Nuclear Power Systems

    Energy Technology Data Exchange (ETDEWEB)

    Stephen M. Bruemmer; Peter L. Andersen; Gary Was

    2002-12-27

    The discovery of a damage-resistant alloy based on Hf solute additions to a low-carbon 316SS is the highlight of the Phase II research. This damage resistance is supported by characterization of radiation-induced microstructures and microchemistries along with measurements of environmental cracking. The addition of Hf to a low-carbon 316SS reduced the detrimental impact of radiation by changing the distribution of Hf. Pt additions reduced the impact of radiation on grain boundary segregation but did not alter its effect on microstructural damage development or cracking. Because cracking susceptibility is associated with several material characteristics, separate effect experiments exploring strength effects using non-irradiated stainless steels were conducted. These crack growth tests suggest that irradiation strength by itself can promote environmental cracking. The second concept for developing damage resistant alloys is the use of metastable precipitates to stabilize the microstructure during irradiation. Three alloys have been tailored for evaluation of precipitate stability influences on damage evolution. The first alloy is a Ni-base alloy (alloy 718) that has been characterized at low neutron irradiation doses but has not been characterized at high irradiation doses. The other two alloys are Fe-base alloys (PH 17-7 and PH 17-4) that have similar precipitate structures as alloy 718 but is more practical in nuclear structures because of the lower Ni content and hence lesser transmutation to He.

  19. NUMERICAL ANALYSES FOR TREATING DIFFUSION IN SINGLE-, TWO-, AND THREE-PHASE BINARY ALLOY SYSTEMS

    Science.gov (United States)

    Tenney, D. R.

    1994-01-01

    This package consists of a series of three computer programs for treating one-dimensional transient diffusion problems in single and multiple phase binary alloy systems. An accurate understanding of the diffusion process is important in the development and production of binary alloys. Previous solutions of the diffusion equations were highly restricted in their scope and application. The finite-difference solutions developed for this package are applicable for planar, cylindrical, and spherical geometries with any diffusion-zone size and any continuous variation of the diffusion coefficient with concentration. Special techniques were included to account for differences in modal volumes, initiation and growth of an intermediate phase, disappearance of a phase, and the presence of an initial composition profile in the specimen. In each analysis, an effort was made to achieve good accuracy while minimizing computation time. The solutions to the diffusion equations for single-, two-, and threephase binary alloy systems are numerically calculated by the three programs NAD1, NAD2, and NAD3. NAD1 treats the diffusion between pure metals which belong to a single-phase system. Diffusion in this system is described by a one-dimensional Fick's second law and will result in a continuous composition variation. For computational purposes, Fick's second law is expressed as an explicit second-order finite difference equation. Finite difference calculations are made by choosing the grid spacing small enough to give convergent solutions of acceptable accuracy. NAD2 treats diffusion between pure metals which form a two-phase system. Diffusion in the twophase system is described by two partial differential equations (a Fick's second law for each phase) and an interface-flux-balance equation which describes the location of the interface. Actual interface motion is obtained by a mass conservation procedure. To account for changes in the thicknesses of the two phases as diffusion

  20. Advanced materials for nuclear reactor systems: Alloys by design to overcome past limitations

    International Nuclear Information System (INIS)

    Advanced materials have the potential to improve reactor performance via increased safety margins, design flexibility, and fast reactor economics and overcome traditional limitations. Increased strength and creep resistance can give greater design margins leading to improved safety margins, longer lifetimes, and higher operating temperatures, thus enabling greater flexibility. Improved mechanical performance may also help reduce the plant capital cost for new reactors both by reducing the required commodities (with concomitant reductions in welding, quality assurance and fabrication costs) and through design simplifications. However, successful implementation requires considerable development and licensing effort. Modern materials science tools such as computational thermodynamics and multiscale radiation damage computational models in conjunction with rapid science-guided experimental validation may offer the potential for a dramatic reduction in the time period to develop and qualify structural materials. There are many requirements for all nuclear reactor structural materials, regardless of the exact design or purpose. All requirements for a materials use in an advanced fast reactor system must be considered and carefully weighed. These factors may include material availability and cost, ease of fabrication and joining, long-term stability, mechanical performance, thermal properties, neutronics, corrosion and compatibility performance, radiation tolerance, and code qualification status. Only through careful evaluation of all factors and a thorough trade analysis will the most promising candidate materials be chosen for further development. It is important to note that there is no ideal material that is best for each of the considerations listed. Indeed, all candidate materials have advantages and limitations. The most promising alloys, which allow the best performance, are also the least technically mature and will require the most substantial effort. These

  1. Formation of alloys in Ti-V system in hydride cycle and synthesis of their hydrides in self-propagating high-temperature synthesis regime

    Energy Technology Data Exchange (ETDEWEB)

    Aleksanyan, A.G., E-mail: a.g.aleks_yan@mail.ru [A.B. Nalbandyan Institute of Chemical Physics of Armenian NAS, 5/2 P.Sevak Str., Yerevan 0014 (Armenia); Dolukhanyan, S.K. [A.B. Nalbandyan Institute of Chemical Physics of Armenian NAS, 5/2 P.Sevak Str., Yerevan 0014 (Armenia); Shekhtman, V.Sh. [Institute of Solid State Physics, RAS, Chernogolovka, Moscow District 142432 (Russian Federation); Huot, J., E-mail: jacques_huot@uqtr.ca [Institut de recherche sur l' hydrogene, Universite du Quebec a Trois-Rivieres (Canada); Ter-Galstyan, O.P.; Mnatsakanyan, N.L. [A.B. Nalbandyan Institute of Chemical Physics of Armenian NAS, 5/2 P.Sevak Str., Yerevan 0014 (Armenia)

    2011-09-15

    Research highlights: > We synthesize Ti-V alloys by new 'hydride cycle' method. Structural characteristics of formed alloys we investigate by X-ray diffraction. > We show that the alloys contain mainly BCC crystal structure. > We investigate the interaction of the synthesized alloys with hydrogen in combustion regime. > We study the properties of hydrides by X-ray, DTA and DSC analyses. - Abstract: In the present work, the possibility of formation of titanium and vanadium based alloys of BCC structure using hydride cycle was investigated. The mechanism of formation of alloys in Ti-V system from the powders of hydrides TiH{sub 2} and VH{sub 0.9} (or of V) by compaction followed by dehydrogenation was studied. Then, the interaction of the synthesized alloys with hydrogen in combustion regime (self-propagating high-temperature synthesis, SHS) resulting in hydrides of these alloys was investigated. DTA and DSC analyses of some alloys and their hydrides were performed and their thermal characteristics were measured.

  2. Portable, real-time alloy identification of metallic wear debris from machinery lubrication systems: laser-induced breakdown spectroscopy versus x-ray fluorescence

    Science.gov (United States)

    Suresh, Pooja

    2014-05-01

    Alloy identification of oil-borne wear debris captured on chip detectors, filters and magnetic plugs allows the machinery maintainer to assess the health of the engine or gearbox and identify specific component damage. Today, such identification can be achieved in real time using portable, at-line laser-induced breakdown spectroscopy (LIBS) and Xray fluorescence (XRF) instruments. Both techniques can be utilized in various industries including aviation, marine, railways, heavy diesel and other industrial machinery with, however, some substantial differences in application and instrument performance. In this work, the performances of a LIBS and an XRF instrument are compared based on measurements of a wide range of typical aerospace alloys including steels, titanium, aluminum and nickel alloys. Measurement results were analyzed with a staged correlation technique specifically developed for the purposes of this study - identifying the particle alloy composition using a pre-recorded library of spectral signatures. The analysis is performed in two stages: first, the base element of the alloy is determined by correlation with the stored elemental spectra and then, the alloy is identified by matching the particle's spectral signature using parametric correlation against the stored spectra of all alloys that have the same base element. The correlation analysis has achieved highly repeatable discrimination between alloys of similar composition. Portable LIBS demonstrates higher detection accuracy and better identification of alloys comprising lighter elements as compared to that of the portable XRF system, and reveals a significant reduction in the analysis time over XRF.

  3. Thermal stability and growth kinetics of the interfacial TiC layer in the Ti alloy/carbon steel system

    International Nuclear Information System (INIS)

    The thermal stability and growth kinetics of the titanium carbide interfacial layer, formed in the course of the diffusion bonding of low-alloy carbon steel (0.3 wt.% C) and Ti alloy, were investigated. Thermal stability of the titanium carbide interfacial layer was evaluated based on the thermodynamic analysis of the Fe–Ti–C ternary system. Thermodynamic analysis of the Fe–Ti–C system confirmed that the titanium carbide layer is stable in contact with the steel part of the diffusion couple. An experiment with inert markers at the interface confirms that growth kinetics of the TiC layer is governed by carbon diffusion from steel to titanium alloy through the titanium carbide phase. In the 800–950 °C temperature range, carbon diffusion in austenite was found to be a rate-determining step of the titanium carbide layer growth during the initial stage of the interaction (<40 min). For advanced stages, the thickness of the layer depends on two simultaneously occurring processes, namely flow of carbon atoms through the titanium carbide layer and that from the titanium carbide layer into the titanium alloy. The estimated values of the carbon diffusion coefficient and the activation energy of the process reflect the grain boundary mechanism of carbon diffusion through the interfacial layer

  4. High strength and high electrical conductivity Cu–Cr system alloys manufactured by hot rolling–quenching process and thermomechanical treatments

    International Nuclear Information System (INIS)

    Highlights: ► HR–Q and thermomechanical treatments are successfully developed to manufacture Cu–Cr system alloys. ► Ordered fcc structure Cr precipitates are considered to be precursors of equilibrium bcc Cr precipitates. ► The Cr precipitates are responsible for the improvement of properties. ► Additions of Zr, Mg and Si bring about significant improvement in properties of Cu–Cr alloy. ► Good properties are ascribed to grain boundary strengthening, strain hardening and precipitation hardening. - Abstract: Cu–Cr system alloy strips were manufactured by an online hot rolling–quenching (HR–Q) process and subsequent thermomechanical treatments. The microstructure and properties of the alloys were investigated by observations of optical microscopy and transmission electron microscopy, and measurements of microhardness and electrical conductivity. The results show that the HR–Q process and thermomechanical treatments are successfully developed to manufacture Cu–Cr system alloy strips with good combinations of strength, conductivity and softening resistance. Ordered fcc structure Cr precipitates, which are decomposed from the thermomechanical treated alloys, are considered to be precursors to the formation of equilibrium bcc Cr precipitates and responsible for the improvement of properties during near peak aging. Small additions of Zr, Mg and Si effectively improve the hardness and softening resistance of Cu–Cr alloy, and slightly reduce the electrical conductivity. The achievement of high strength and high electrical conductivity in the alloys is ascribed to the interactions of grain boundary strengthening, strain hardening and precipitation hardening.

  5. Development of a new hydrogen purification system by using hydrogen absorbing alloy for generator cooling; Suiso kyuzo gokin riyo hatsudenkinai suiso jundo kojo system no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Haruki, N.; Sato, J.; Kogi, T.; Nishimura, Y. [Kansai Electric Power Co., Inc., Osaka (Japan); Takeda, H. [Japan Steel works Ltd., Tokyo (Japan)] Fujita, T. [Mitsubishi Electric Corp., Tokyo (Japan)

    1997-05-20

    Hydrogen absorbing alloys have a number of useful functions, such as energy conversion, hydrogen storage and purification. As an application to separation and purification of hydrogen, we have developed a new hydrogen purification system by using a hydrogen absorbing alloy for generator cooling. For demonstration testing with an actual machine, a hydrogen recovery and purification device using 120kg of alloy was manufactured and installed on No.5 turbine-synchronous generator at Himeji No.2 power station. This device is designed to improve the purity of the hydrogen gas in generator containing impurities such as nitrogen and oxygen. The test results tell that the purity of the hydrogen gas in the generator can be enhanced from 98% to 99.9% and maintained at this level under continuous operation. An application of the hydrogen purification system is expected to decrease the generator`s windage loss, resulting higher generator efficiency. 2 refs., 18 figs.

  6. Phase identification in In-Fe-B system alloys produced by carbothermic reduction of oxides

    International Nuclear Information System (INIS)

    A study is made into phase composition of Nd-Fe-B-C-O alloy castings intended for permanent magnets fabrication. Main phase in the standard Nm34R alloy is known to be Nd2Fe14B. The use of the least square method for Z-ray diffraction spectra processing and of laser microanalyzer makes it possible to reveal two phases of the following compositions at %: 86Nd-14B-0.4C and 74Fe-23B-3C. It is concluded that in the alloy produced by carbothermic reduction of NdFeO3 and NdBO3 practically all carbon dissolves in iron constituent. Minimization of carbon content in the alloy is reduced to that in Fe-C alloys. This process may be performed by well-known methods. 12 refs., 2 figs

  7. A metallurgical approach toward alloying in rare earth permanen magnet systems

    Energy Technology Data Exchange (ETDEWEB)

    Branagan, D. J.

    1995-02-23

    The approach was developed to allow microstructural enhancement and control during solidification and processing. Compound additions of Group IVA, VA, or VIA transition metals (TM) and carbon were added to Nd{sub 2}Fe{sub 14}B (2-14-1). Transition metal carbides formed in IVA (TiC, ZrC, HfC) and Group VA (VC, NbC, TaC) systems, but not in the VIA system. The alloying ability of each TM carbide was graded using phase stability, liquid and equilibrium solid solubility, and high temperature carbide stability. Ti with C additions was chosen as the best system. The practically zero equilibrium solid solubility means that the Ti and C additions will ultimately form TiC after heat treatment which allows the development of a composite microstructure consisting of the 2-14-1 phase and TiC. Thus, the excellent intrinsic magnetic properties of the 2-14-1 phase remain unaltered and the extrinsic properties relating to the microstructure are enhanced due to the TiC stabilized microstructure which is much more resistant to grain growth. When Ti + C are dissolved in the liquid melt or solid phases, such as the glass or 2-14-1 phase, the intrinsic properties are changed; favorable changes include increased glass forming ability, reduced optimum cooling rate, increased optimum energy product, and enhanced nucleation kinetics of crystallization.

  8. Biochemical Contributions to Corrosion of Carbon Steel and Alloy 22 in a Continual Flow System

    International Nuclear Information System (INIS)

    Microbiologically influenced corrosion (MIC) may decrease the functional lifetime of nuclear waste packaging materials in the potential geologic repository at Yucca Mountain (YM), Nevada. Biochemical contributions to corrosion of package materials are being determined in reactors containing crushed repository-site rock with the endogenous microbial community, and candidate waste package materials. These systems are being continually supplied with simulated ground water. Periodically, bulk chemistries are analyzed on the system outflow, and surfacial chemistries are assessed on withdrawn material coupons. Both Fe and Mn dissolved from C1020 coupons under conditions that included the presence of YM microorganisms. Insoluble corrosion products remained in a reduced state at the coupon surface, indicating at least a localized anoxic condition; soluble reduced Mn and Fe were also detected in solution, while precipitated and spalled products were oxidized. Alloy 22 surfaces showed a layer of chrome oxide, almost certainly in the Cr(III) oxidation state, on microcosm-exposed coupons, while no soluble chrome was detected in solution. The results of these studies will be compared to identical testing on systems containing sterilized rock to generate, and ultimately predict, microbial contributions to waste package corrosion chemistries

  9. 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. .

  10. Physicochemical study of alloys of the system GeTe-Ag2Te and their electrophysical properties

    International Nuclear Information System (INIS)

    Using the methods of differential thermal, X-ray phase, mi mi microstructural analyses and according to the measurement of microhardness of the alloys the interaction between GeTe and Ag2, Te is studied, the T-x projection of phase diagram of the condensed system GeTe-Ag2Te is built. In the system the 8Ag2Tex3GeTe compound is found, which melts incongruently at 883 K (610 deg C). The boundaries of the regions of solid solutions on the basis of the components of the system are determined. It is found that the solid solutions on the basis of components undergo polymorphous transformations. The coefficients of thermo e.m.f., specific electric conductivity, thermal conductivity, Hall coefficient are measured and thermoelectric soundness of alloys is determined

  11. Applying a new criterion to predict glass forming alloys in the Zr–Ni–Cu ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Déo, L.P., E-mail: leonardopratavieira@gmail.com [Universidade de São Paulo, EESC, SMM - Av. Trabalhador São Carlense, 400 – São Carlos, SP 13566-590 (Brazil); Mendes, M.A.B., E-mail: marcio.andreato@gmail.com [Universidade Federal de São Carlos, DEMa - Rod. Washington Luiz, Km 235 – São Carlos, SP 13565-905 (Brazil); Costa, A.M.S., E-mail: alexmatos1980@gmail.com [Universidade de São Paulo, DEMAR, EEL – Polo Urbo-Industrial Gleba AI-6, s/n – Lorena, SP 12600-970 (Brazil); Campos Neto, N.D., E-mail: nelsonddcn@gmail.com [Universidade de São Paulo, EESC, SMM - Av. Trabalhador São Carlense, 400 – São Carlos, SP 13566-590 (Brazil); Oliveira, M.F. de, E-mail: falcao@sc.usp.br [Universidade de São Paulo, EESC, SMM - Av. Trabalhador São Carlense, 400 – São Carlos, SP 13566-590 (Brazil)

    2013-03-15

    Highlights: ► Calculation to predict and select the glass forming ability (GFA) of metallic alloys in Zr–Ni–Cu system. ► Good correlation between theoretical and experimental GFA samples. ► Combination of X-ray diffraction (XRD) and differential scanning calorimetry (DSC) techniques mainly to characterize the samples. ► Oxygen impurity dramatically reduced the GFA. ► The selection criterion used opens the possibility to obtain new amorphous alloys, reducing the experimental procedures of trial and error. -- Abstract: A new criterion has been recently proposed to predict and select the glass forming ability (GFA) of metallic alloys. It was found that the critical cooling rate for glass formation (R{sub c}) correlates well with a proper combination of two factors, the minimum topological instability (λ{sub min}) and the thermodynamic parameter (Δh). The (λ{sub min}) criterion is based on the concept of topological instability of stable crystalline structures and (Δh) depends on the average work function difference (Δϕ) and the average electron density difference Δn{sub ws}{sup 1/3} among the constituent elements of the alloy. In the present work, the selection criterion was applied in the Zr–Ni–Cu system and its predictability was analyzed experimentally. Ribbon-shaped and splat-shaped samples were produced by melt-spinning and splat-cooling techniques respectively. The crystallization content and behavior were analyzed by X-ray diffraction (XRD) and differential scanning calorimetry (DSC), respectively. The results showed a good correlation between the theoretical GFA values and the amorphous phase percentages found in different alloy compositions.

  12. Controller Parameter Tuning for Systems with Hysteresis and Its Application to Shape Memory Alloy Actuators

    Science.gov (United States)

    Wakasa, Yuji; Kanagawa, Shinji; Tanaka, Kanya; Nishimura, Yuki

    This paper proposes a simple controller parameter tuning method that can compensate for hysteresis. The proposed method is based on the so-called fictitious reference iterative tuning (FRIT) technique which can easily tune controller parameters such as proportional-integral-derivative gains using a one-shot closed-loop experimental data. In the proposed framework, a simple hysteresis model is introduced to a control system, and its inverse is used as a hysteresis compensator. Since the hysteresis model is characterized with only three parameters, the related computational burden is moderate in the parameter tuning process. Also, the proposed FRIT method needs an only one-shot experiment as in the standard FRIT one, which implies that the feature of FRIT is well-maintained. In the optimization process, the so-called covariance matrix adaptation evolution strategy is used for simultaneously searching hysteresis parameters as well as controller parameters. The proposed FRIT method is applied to an experimental control system that comprises a shape memory alloy actuator, and its effectiveness is verified.

  13. Mechanisms Governing the Creep Behavior of High Temperature Alloys for Generation IV Nuclear Energy Systems

    Energy Technology Data Exchange (ETDEWEB)

    Vasudevan, Vijay [Univ. of Cincinnati, OH (United States); Carroll, Laura [Idaho National Lab. (INL), Idaho Falls, ID (United States); Sham, Sam [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-04-06

    This research project, which includes collaborators from INL and ORNL, focuses on the study of alloy 617 and alloy 800H that are candidates for applications as intermediate heat exchangers in GEN IV nuclear reactors, with an emphasis on the effects of grain size, grain boundaries and second phases on the creep properties; the mechanisms of dislocation creep, diffusional creep and cavitation; the onset of tertiary creep; and theoretical modeling for long-term predictions of materials behavior and for high temperature alloy design.

  14. Effect of Alloying Elements to Aluminium on the Wettability of AL/SiC System

    OpenAIRE

    CANDAN, Ercan

    2002-01-01

    The wettability at a liquid Al-alloy/SiC interface was evaluated by the sessile drop method at 750oC. The wetting angle, q ,of a sessile drop on SiC substrate decreased with the addition of Pb, Mg and Ca to pure aluminium. The reduction in q of the Al-Pb alloy was proportional to the reduction in surface tension, glv, of aluminium, whereas in Al-Mg and Al-Ca alloys the reduction in q was greater than the reduction in g lv of Al. This was attributed to reactions that took place at the Al-all...

  15. Performance of tantalum-tungsten alloy selective emitters in thermophotovoltaic systems

    Science.gov (United States)

    Stelmakh, Veronika; Rinnerbauer, Veronika; Chan, Walker R.; Senkevich, Jay J.; Joannopoulos, John D.; Soljačić, Marin; Celanovic, Ivan

    2014-06-01

    A tantalum tungsten solid solution alloy, Ta 3% W, based 2D photonic crystal (PhC) was designed and fabricated for high-temperature energy conversion applications. Ta 3% W presents advantages compared to the non-alloys as it combines the better high-temperature thermomechanical properties of W with the more compliant material properties of Ta, allowing for a direct system integration path of the PhC as selective emitter/absorber into a spectrum of energy conversion systems. Indeed metallic PhCs are promising as high performance selective thermal emitters for thermophotovoltaics (TPV), solar thermal, and solar TPV applications due to the ability to tune their spectral properties and achieve highly selective emission. A 2D PhC was designed to have high spectral selectivity matched to the bandgap of a TPV cell using numerical simulations and fabricated using standard semiconductor processes. The emittance of the Ta 3% WPhC was obtained from near-normal reectance measurements at room temperature before and after annealing at 1200 °C for 24h in vacuum with a protective coating of 40 nm HfO2, showing high selectivity in agreement with simulations. SEM images of the cross section of the PhC prepared by FIB confirm the structural stability of the PhC after anneal, i.e. the coating effectively prevented structural degradation due to surface diffusion. The mechanical and thermal stability of the substrate was characterized as well as the optical properties of the fabricated PhC. To evaluate the performance of the selective emitters, the spectral selectivity and useful emitted power density are calculated as a function of operating temperature. At 1200 °C, the useful emitted irradiance is selectively increased by a factor of 3 using the selective emitter as compared to the non-structured surface. All in all, this paper demonstrates the suitability of 2D PhCs fabricated on polycrystalline Ta-W substrates with an HfO2 coating for TPV applications.

  16. Investigation of the structure and properties of the titanium alloy of the Ti-Al-Mo-V-Fe-Cu-Zr-Sn system

    International Nuclear Information System (INIS)

    The alloys of martensitic type in the Ti-Al-Mo-V-Fe-Cu-Zr-Sn system after heat treatment are investigated. To determine the composition of the titanium alloy methods of mathematical planning of the experiment are applied. Results of mechanical tests of the alloys are presented, as well as coefficients of models for the properties, calculated according to these data. The investigation establishes the composition of a high-strength titanium alloy of a martensitic type, containing 4.5-60 % Al, 2.0-4.0 % Mo, 0.5-1.9 % V, 0.3-1.5 % Fe, 0.3-1.5 % Cu, 1.5-3.0 % Sn, 2.0-4.0 % Zr. The semiproducts, produced by deformation in β-field, after heat treatment have an ultimate strength >=120 kg/mm2, satisfactory ductility and reliability. The alloy possesses rather a high heat resistance and can be operated at 400-500 deg C

  17. Indoor atmospheric corrosion of historical ferrous alloys. System characterisation, mechanisms and modelling discussion

    International Nuclear Information System (INIS)

    Understanding the mechanisms of indoor atmospheric corrosion in iron alloys is of primary importance in several fields, including for the conservation of Middle Ages monuments or the long term storage of nuclear waste. In this research, a double approach was developed, combining fine characterisation of corrosion systems and design of experiments to answers specific questions related to mechanisms understanding. Iron indoor atmospheric corrosion was investigated on samples coming from the reinforcing chain of the Amiens cathedral (15. century). In the first stage, the corrosion system has been extensively characterised from the macroscopic to the nano-metric scale. In particular, structural micro-analysis (μ-Raman, μ-XRD, μ-XAS) has been used to locate, identify and quantify the oxidised phases. Rust layers are composed of a matrix of nano-metric goethite, with low quantities of lepidocrocite and akaganeite mostly located in the extern part of the corrosion system. In addition, clear marblings are dispersed in the matrix, which are sometimes connected with the metal core. Although these may contain maghemite, these marblings are generally made of ferri-hydrite/feroxyhite phases. In the second stage, specific experiments have been carried out in an unsaturated marked medium to locate oxygen reduction sites in the rust layers. Several cases were evidenced, depending on the rust layer morphology. In addition, reduction processes of model phases have been studied in situ, using an electrochemical cell coupled with structural characterisation techniques. This combination highlighted the influence of reduction mode and pH on the type of reduced phase formed. From the obtained results, several mechanisms are proposed to explain the long term indoor atmospheric corrosion of iron, including rust layers morphology and phases properties. The different hypotheses have been integrated in a proposed method to diagnosis ancient ferrous systems stability. These hypotheses also

  18. Lattice parameters values and phase diagram for the Cu2Zn1-zFezGeSe4 alloy system

    International Nuclear Information System (INIS)

    X-ray powder diffraction and differential thermal analysis (DTA) measurements were made on polycrystalline samples of the Cu2Zn1-zFezGeSe4 alloy system. The diffraction patterns were used to show the equilibrium conditions and to estimate crystalline parameter values. It was found that, at room temperature, a single phase solid solution with the tetragonal stannite α structure (I4-bar2m) occurs across the whole composition range. The DTA thermograms were used to construct the phase diagram of the Cu2Zn1-zFezGeSe4 alloy system. It was confirmed that the Cu2ZnGeSe4 compound melts incongruently. It was observed that undercooling effects occur for samples with z > 0.9

  19. Low spring index, large displacement Shape Memory Alloy (SMA) coil actuators for use in macro- and micro-systems

    Science.gov (United States)

    Holschuh, Brad; Newman, Dava

    2014-03-01

    Shape memory alloys (SMA) offer unique shape changing characteristics that can be exploited to produce low­ mass, low-bulk, large-stroke actuators. We are investigating the use of low spring index (defined as the ratio of coil diameter to wire diameter) SMA coils for use as actuators in morphing aerospace systems. Specifically, we describe the development and characterization of minimum achievable spring index coiled actuators made from 0.3048 mm (0.012") diameter shape memory alloy (SMA) wire for integration in textile architectures for future compression space suit applications. Production and shape setting of the coiled actuators, as well as experimental test methods, are described. Force, length and voltage relationships for multiple coil actuators are reported and discussed. The actuators exhibit a highly linear (R2 designs, and the broader viability of these actuators in both macro- and micro-systems, are presented.

  20. INFLUENCE OF NONEQUILIBRIUM CONDITIONS OF HARDENING ON MECHANICAL PROPERTIES FOUNDINGS RECEIVED ON THE BASIS OF ALLOYS OF SYSTEM Al-Si-Cu

    OpenAIRE

    Доценко, Юрий Валериевич

    2010-01-01

    The analysis of results of researches on modifying influence by ultradisperse modifier TiCN and gaz-dynamyc influences on mechanical foundings properties received of aluminium alloys of system Al-Si-Cu is resulted.

  1. The role of off-diagonal disorder on alloy phase stability: An application to the Ni-Pt system

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-12-10

    The occurrence of ordering in the Ni-Pt alloy system seems to violate theoretical predictions based on a tight-binding description of the electronic structure. In these descriptions of transition metal alloys, ordering is predicted if the d-band is about half filled, and phase separation is predicted if the d-band is almost empty or almost full. This so-called bandfilling argument clearly fails in the case of Ni-Pt alloys, which order despite an almost filled d-band. The band filling rule is derived under the assumption that off-diagonal disorder (ODD), that is, the difference in d-bandwidths of the constituents, can be ignored. However, it has been argued that taking ODD into account would result in an even stronger phase separation tendency in the theoretical prediction. Magnetism is not a factor in equiatomic Ni-Pt alloys, and thus can not be invoked to correct the erroneous prediction. Other factors, such as spin orbit coupling in the relativistic description of Pt can change the prediction only if very large spin orbit splitting is assumed on the Pt atom. In this paper, the effect of ODD is examined and evaluated. It has been shown that when ODD is taken into account, ordering is indeed predicted although the order-disorder temperatures tend to be lower than those experimentally observed. The densities of states (DOE) computed with, and without ODD are contrasted and the energetic properties as defined by the Generalized Perturbation Method (GPM) are employed to determine the ground state of the alloy at three compositions, Ni{sub 3}Pt, NiPt, and NiPt{sub 3}, and to compute order-disorder temperatures.

  2. ENVIRONMENTALLY COMPLIANT CORROSION-ACTIVATED INHIBITOR SYSTEM FOR ALUMINUM ALLOYS - PHASE I

    Science.gov (United States)

    The federal government is estimated to spend $1 billion on painting/repainting aircraft annually. Aircraft have surfaces composed of aluminum alloys that are highly susceptible to corrosion and must be protected with corrosion-preventative treatments that typically conta...

  3. The effect of the solute on the structure, selected mechanical properties, and biocompatibility of Ti–Zr system alloys for dental applications

    International Nuclear Information System (INIS)

    New titanium alloys have been developed with the aim of utilizing materials with better properties for application as biomaterials, and Ti–Zr system alloys are among the more promising of these. In this paper, the influence of zirconium concentrations on the structure, microstructure, and selected mechanical properties of Ti–Zr alloys is analyzed. After melting and swaging, the samples were characterized through chemical analysis, density measurements, X-ray diffraction, optical microscopy, Vickers microhardness, and elasticity modulus. In-vitro cytotoxicity tests were performed on cultured osteogenic cells. The results showed the formation essentially of the α′ phase (with hcp structure) and microhardness values greater than cp-Ti. The elasticity modulus of the alloys was sensitive to the zirconium concentrations while remaining within the range of values of conventional titanium alloys. The alloys presented no cytotoxic effects on osteoblastic cells in the studied conditions. - Highlights: • Ti–Zr alloys for biomedical applications were developed. • Only α′ phase was observed. • Influence of zirconium concentrations on the properties of Ti–Zr alloys was analyzed. • No cytotoxic effects were observed

  4. The effect of the solute on the structure, selected mechanical properties, and biocompatibility of Ti–Zr system alloys for dental applications

    Energy Technology Data Exchange (ETDEWEB)

    Correa, D.R.N.; Vicente, F.B. [UNESP — Univ. Estadual Paulista, Laboratório de Anelasticidade e Biomateriais, 17.033-360, Bauru, SP (Brazil); Donato, T.A.G.; Arana-Chavez, V.E. [USP — Universidade de São Paulo, Faculdade de Odontologia, Departamento de Biologia Oral e Biomateriais, 05.508-900, São Paulo, SP (Brazil); Buzalaf, M.A.R. [USP — Universidade de São Paulo, Faculdade de Odontologia de Bauru, Departamento de Ciências Biológicas, 17.012-901, Bauru, SP (Brazil); Grandini, C.R., E-mail: betog@fc.unesp.br [UNESP — Univ. Estadual Paulista, Laboratório de Anelasticidade e Biomateriais, 17.033-360, Bauru, SP (Brazil)

    2014-01-01

    New titanium alloys have been developed with the aim of utilizing materials with better properties for application as biomaterials, and Ti–Zr system alloys are among the more promising of these. In this paper, the influence of zirconium concentrations on the structure, microstructure, and selected mechanical properties of Ti–Zr alloys is analyzed. After melting and swaging, the samples were characterized through chemical analysis, density measurements, X-ray diffraction, optical microscopy, Vickers microhardness, and elasticity modulus. In-vitro cytotoxicity tests were performed on cultured osteogenic cells. The results showed the formation essentially of the α′ phase (with hcp structure) and microhardness values greater than cp-Ti. The elasticity modulus of the alloys was sensitive to the zirconium concentrations while remaining within the range of values of conventional titanium alloys. The alloys presented no cytotoxic effects on osteoblastic cells in the studied conditions. - Highlights: • Ti–Zr alloys for biomedical applications were developed. • Only α′ phase was observed. • Influence of zirconium concentrations on the properties of Ti–Zr alloys was analyzed. • No cytotoxic effects were observed.

  5. Alloys in energy development

    International Nuclear Information System (INIS)

    The development of new and advanced energy systems often requires the tailoring of new alloys or alloy combinations to meet the novel and often stringent requirements of those systems. Longer life at higher temperatures and stresses in aggressive environments is the most common goal. Alloy theory helps in achieving this goal by suggesting uses of multiphase systems and intermediate phases, where solid solutions were traditionally used. However, the use of materials under non-equilibrium conditions is now quite common - as with rapidly solidified metals - and the application of alloy theory must be modified accordingly. Under certain conditions, as in a reactor core, the rate of approach to equilibrium will be modified; sometimes a quasi-equilibrium is established. Thus an alloy may exhibit enhanced general diffusion at the same time as precipitate particles are being dispersed and solute atoms are being carried to vacancy sinks. We are approaching an understanding of these processes and can begin to model these complex systems

  6. Injection Molding of Titanium Alloy Implant For Biomedical Application Using Novel Binder System Based on Palm Oil Derivatives

    OpenAIRE

    Ibrahim, R.; M. Azmirruddin; Jabir, M; Ismail, M. R.; M. Muhamad; R. Awang; Muhamad, S.

    2010-01-01

    Problem statement: Titanium alloy (Ti6Al4V) has been widely used as an implant for biomedical application. In this study, the implant had been fabricated using high technology of Powder Injection Molding (PIM) process due to the cost effective technique for producing small, complex and precision parts in high volume compared with conventional method through machining. Approach: Through PIM, the binder system is one of the most important criteria in order to successfully fabricate the implants...

  7. Some features of beryllium corrosion behavior in Be-liquid Li-V-4Ti-4Cr alloy system

    International Nuclear Information System (INIS)

    Recent experimental results on beryllium corrosion behavior in a V-4Ti-4Cr alloy, liquid lithium static system during testing for 200-500 h at temperatures from 600 to 800 deg. C are presented. The influence of test conditions (temperature, duration and lithium purity) and beryllium characteristics (microstructure, grain size and chemical composition) on weight loss of beryllium and penetration of lithium into beryllium are discussed. Results of compressive tests for beryllium specimens before and after corrosion testing are also introduced

  8. Study on electrodeposition of La-Mg alloys in chloride system with molten salt electrolysis process

    International Nuclear Information System (INIS)

    This work presents the study on electrochemical codeposition of La-Mg alloys on molybdenum electrode in LaCl3-MgCl2-LiCl-KCl melt. The feasibility of alloy deposition was studied extensively by implementing electro analytical techniques like cyclic voltametry, square wave voltametry and chronopotentiometry in a temperature range of 923 to 1023K. The mechanism of codeposition was also studied implementing the above mentioned transient electrochemical techniques. The components of the alloy element can be controlled by fixing the concentration of feeding salt in the electrolyte. Based on this basic investigation, deposition of La-Mg alloys were attempted on molybdenum electrode at higher operating temperature above 1073K to obtain the product in liquid state to have better purity. The material has been prepared in 200-300g scale to support practical application. Different phases of La-Mg alloys could be prepared by galvanostatic electrolysis by varying the concentration of LaCl3 and MgCl2 in the feed material. X-ray diffraction (XRD) and Scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) techniques were implemented to characterize the phase and microstructure of the alloys respectively. Inductively couple plasma-atomic emission spectroscopy (ICP-AES) analyses of the obtained products by electrolysis showed that chemical compositions of La-Mg alloys were consistent with XRD results. The effects of various process parameters such as concentration of magnesium chloride in bath, temperature of electrolysis and cathode current density on current efficiency have been investigated. These parameters were standardized to get highest current efficiency and yield in preparing La-Mg alloys in 200-300 g scale in our lab set-up. (author)

  9. Compatibility of refractory alloys with space reactor system coolants and working fluids

    International Nuclear Information System (INIS)

    The bulk of this report deals with compatibility studies in liquid lithium and boiling potassium. Substantial information is also presented concerning the reactivity of niobium and tantalum alloys with residual gases in high and ultrahigh vacuum atmospheres. The remaining information, which is much less extensive, covers the compatibility behavior of molybdenum and tungsten alloys in alkali metals and a qualitative assessment of the use of refractory metals for containing helium in a closed Brayton cycle. 22 references, 29 figures, 14 tables

  10. Investigation into thermodynamic properties of indium-copper system alloys by method of instant emf registration

    International Nuclear Information System (INIS)

    Direct measurement of activity of In-Cu alloy both components is carried out. Thermodynamic properties of (In0.147Cu0.853; In0.326Cu0.674; In0.341Cu0.659; In0.302Cu0.638; In0.617Cu0.383) alloys calculated proceeding from the measured activities, well agree with each other and the literary data. 6 refs.; 3 tabs

  11. Constituent phase diagrams of the Al-Cu-Fe-Mg-Ni-Si system and their application to the analysis of aluminium piston alloys

    Energy Technology Data Exchange (ETDEWEB)

    Belov, N.A. [Moscow Institute of Steel and Alloys, Leninsky prosp. 4, Moscow 119049 (Russian Federation); Eskin, D.G. [Netherlands Institute for Metals Research, Rotterdamseweg 137, 2628AL Delft (Netherlands)]. E-mail: deskin@nimr.nl; Avxentieva, N.N. [Moscow Institute of Steel and Alloys, Leninsky prosp. 4, Moscow 119049 (Russian Federation)

    2005-10-15

    The evaluation of phase equilibria in quinary systems that constitute the commercially important Al-Cu-Fe-Mg-Ni-Si alloying system is performed in the compositional range of casting alloys by means of metallography, electron probe microanalysis, X-ray diffractometry, differential scanning calorimetry, and by the analysis of phase equilibria in the constituent systems of lesser dimensionality. Suggested phase equilibria are illustrated by bi-, mono- and invariant solidification reactions, polythermal diagrams of solidification, distributions of phase fields in the solid state, and isothermal and polythermal sections. Phase composition of as-cast alloys is analyzed in terms of non-equilibrium solidification. It is shown that the increase in copper concentration in piston Al-Si alloys results in the decrease in the equilibrium solidus from 540 to 505 deg C. Under non-equilibrium solidification conditions, piston alloys finish solidification at {approx}505 deg C. Iron is bound in the quaternary Al{sub 8}FeMg{sub 3}Si{sub 6} phase in low-iron alloys and in the ternary Al{sub 9}FeNi and Al{sub 5}FeSi phases in high-iron alloys.

  12. Constituent phase diagrams of the Al-Cu-Fe-Mg-Ni-Si system and their application to the analysis of aluminium piston alloys

    International Nuclear Information System (INIS)

    The evaluation of phase equilibria in quinary systems that constitute the commercially important Al-Cu-Fe-Mg-Ni-Si alloying system is performed in the compositional range of casting alloys by means of metallography, electron probe microanalysis, X-ray diffractometry, differential scanning calorimetry, and by the analysis of phase equilibria in the constituent systems of lesser dimensionality. Suggested phase equilibria are illustrated by bi-, mono- and invariant solidification reactions, polythermal diagrams of solidification, distributions of phase fields in the solid state, and isothermal and polythermal sections. Phase composition of as-cast alloys is analyzed in terms of non-equilibrium solidification. It is shown that the increase in copper concentration in piston Al-Si alloys results in the decrease in the equilibrium solidus from 540 to 505 deg C. Under non-equilibrium solidification conditions, piston alloys finish solidification at ∼505 deg C. Iron is bound in the quaternary Al8FeMg3Si6 phase in low-iron alloys and in the ternary Al9FeNi and Al5FeSi phases in high-iron alloys

  13. 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...

  14. Development of a rotor alloy for advanced ultra super critical turbine power generation system

    Energy Technology Data Exchange (ETDEWEB)

    Miyashita, Shigekazu; Yamada, Masayuki; Suga, Takeo; Imai, Kiyoshi; Nemoto, Kuniyoshi; Yoshioka, Youmei [Toshiba Corporation, Yokohama (Japan)

    2008-07-01

    A Ni-based superalloy ''TOS1X'', for the rotor material of the 700 class advanced ultra super critical (A-USC) turbine power generation system was developed. TOS1X is an alloy that is improved in the creep rupture strength of Inconel trademark 617 maintaining both forgeability and weldability. The 7 t weight model rotor made of TOS1X was manufactured by double melt process, vacuum induction melting and electro slag remelting, and forging. During forging process, forging cracks and any other abnormalities were not detected on the ingots. The metallurgical and the mechanical properties in this rotor were investigated. Macro and micro structure observation, and some mechanical tests were conducted. According to the metallurgical structure investigation, there was no remarkable segregation in whole area and the forging effect was reached in the center part of the rotor ingot. The results of tensile test and creep rupture test proved that proof stress and tensile stress of the TOS1X are higher than those of Inconel trademark 617 and creep rupture strength of TOS1X is much superior than that of Inconel trademark 617. (orig.)

  15. Cluster-variation calculation for random-field systems: Application to hydrogen in niobium alloys

    International Nuclear Information System (INIS)

    The cluster-variation method is applied to random-field lattice systems and specifically used to model the disorder-disorder phase transition of hydrogen in niobium-molybdenum and niobium-vanadium alloys. A small concentration of molybdenum or vanadium in the niobium lattice is treated as adding at each hydrogen site a random energy with a known probability distribution. Pairwise interactions between hydrogen atoms are included out to the first fifty shells on the bcc tetrahedral interstitial lattice, allowing for the effect of site blocking for the first three shells. The results show the small and large depression in the critical temperature for Nb/sub 1-//sub y/V/sub y/H/sub x/ and Nb/sub 1-//sub y/Mo/sub y/H/sub x/, respectively, with increasing concentration of V or Mo, as observed in experiments. Comparison is made with Monte Carlo calculations of other workers with use of the same interaction parameters, and the effects of variations in the random-energy distribution are described

  16. Titanium alloys. Advances in alloys, processes, products and applications

    OpenAIRE

    Blenkinsop, P.

    1993-01-01

    The last few years have been a period of consolidation of existing alloys and processes. While the aerospace industry remains the principal driving force for alloy development, the paper illustrates examples of new markets being established in "older" alloys, by a combination of product/process development and a re-examination of engineering design parameters. Considerable attention is still being directed towards the titanium aluminide systems, but other more conventional alloy developments ...

  17. High temperature niobium alloys

    International Nuclear Information System (INIS)

    Niobium alloys are currently being used in various high temperature applications such as rocket propulsion, turbine engines and lighting systems. This paper presents an overview of the various commercial niobium alloys, including basic manufacturing processes, properties and applications. Current activities for new applications include powder metallurgy, coating development and fabrication of advanced porous structures for lithium cooled heat pipes

  18. Shape-retainment control using an antagonistic shape memory alloy system

    Science.gov (United States)

    Ikeda, T.; Sawamura, K.; Senba, A.; Tamayama, M.

    2015-04-01

    Since shape memory alloy (SMA) actuators can generate large force per unit weight, they are expected as one of the next generation actuators for aircraft. To keep a position of conventional control surfaces or morphing wings with SMA actuators, the SMA actuators must keep being heated, and the heating energy is not small. To save the energy, a new control method proposed for piezoelectric actuators utilizing hysteresis in deformation [Ikeda and Takahashi, Proc. SPIE 8689 (2013), 86890C] is applied to an antagonistic SMA system. By using the control method any position can be an equilibrium point within hysteresis of stress-strain diagrams. To confirm a feasibility of the control method, a fundamental experiment is performed. The SMA wires are heated by applying electric current to the wires. When a pulsed current is applied to the two SMA wires alternately, the equilibrium position changes between two positions alternately, and when a series of pulse whose amplitude increases gradually is applied to one SMA wire, the equilibrium position changes like a staircase. However, just after the pulse the position returns slightly, that is, overshoot takes place. To investigate such a behavior of the system, numerical simulation is also performed. The one-dimensional phase transformation model [Ikeda, Proc. SPIE 5757 (2005), 344-352] is used for a constitutive model of the SMA wires. The simulated result agrees with the experiment qualitatively, including the overshoot. By examining volume fraction of each phase, it is found that the overshoot is caused by that austenite phase transforms into stress-induced martensite phase during the cooling process after the pulse.

  19. Refractory alloy component fabrication

    International Nuclear Information System (INIS)

    Purpose of this report is to describe joining procedures, primarily welding techniques, which were developed to construct reliable refractory alloy components and systems for advanced space power systems. Two systems, the Nb-1Zr Brayton Cycle Heat Receiver and the T-111 Alloy Potassium Boiler Development Program, are used to illustrate typical systems and components. Particular emphasis is given to specific problems which were eliminated during the development efforts. Finally, some thoughts on application of more recent joining technology are presented. 78 figures

  20. Benchmarking of thermalhydraulic loop models for lead-alloy-cooled advanced nuclear energy systems. Phase I: Isothermal forced convection case

    International Nuclear Information System (INIS)

    Under the auspices of the NEA Nuclear Science Committee (NSC), the Working Party on Scientific Issues of the Fuel Cycle (WPFC) has been established to co-ordinate scientific activities regarding various existing and advanced nuclear fuel cycles, including advanced reactor systems, associated chemistry and flowsheets, development and performance of fuel and materials and accelerators and spallation targets. The WPFC has different expert groups to cover a wide range of scientific issues in the field of nuclear fuel cycle. The Task Force on Lead-Alloy-Cooled Advanced Nuclear Energy Systems (LACANES) was created in 2006 to study thermal-hydraulic characteristics of heavy liquid metal coolant loop. The objectives of the task force are to (1) validate thermal-hydraulic loop models for application to LACANES design analysis in participating organisations, by benchmarking with a set of well-characterised lead-alloy coolant loop test data, (2) establish guidelines for quantifying thermal-hydraulic modelling parameters related to friction and heat transfer by lead-alloy coolant and (3) identify specific issues, either in modelling and/or in loop testing, which need to be addressed via possible future work. Nine participants from seven different institutes participated in the first phase of the benchmark. This report provides details of the benchmark specifications, method and code characteristics and results of the preliminary study: pressure loss coefficient and Phase-I. A comparison and analysis of the results will be performed together with Phase-II

  1. Performance of single wire earth return transformers with amorphous alloy core in a rural electric energy distribution system

    Directory of Open Access Journals (Sweden)

    Benedito Antonio Luciano

    2012-10-01

    Full Text Available In this paper are presented some considerations about the performance of single wire earth return amorphous alloy core transformers in comparison with conventional silicon steel sheets cores transformers used in rural electric energy distribution network. It has been recognized that amorphous metal core transformers improve electrical power distribution efficiency by reducing transformer core losses. This reduction is due to some electromagnetic properties of the amorphous alloys such as: high magnetic permeability, high resistivity, and low coercivity. Experimental results obtained with some single-phase, 60 Hz, 5 kVA amorphous core transformers installed in a rural area electric distribution system in Northern Brazil have been confirming their superior performance in comparison to identical nominal rated transformers built with conventional silicon steel cores, particularly with regard to the excitation power and to the no-load losses.

  2. Temperature dependence of strength, ductility and impact strength for quenched alloys of Fe-Cr-Mn system at 20, -196 and -253 deg C

    International Nuclear Information System (INIS)

    Physical and mechanical properties of 48 alloys, belonging to different phase regions of a quenched state diagram for Fe-Cr-Mn system (containing about 0.03% of C) at 20, -196 and -253 deg C, are studied. Alloys of a different strength, plasticity and impact strength level are revealed. The region of austenitic alloys, containing 10-14% Cr and 24-30% Mn and having maximum values of relative elongation (> 50%) and impact strength (KCV > 2.6 MJ/m2) at cryogenic temperatures, is found

  3. Research on change of phase transformation temperatures and electrical resistance triggered by heat treatment of alloy from Cu-Mn system

    Science.gov (United States)

    Karakaya, N.; Aldirmaz, E.

    2016-05-01

    This paper is aimed at studying influence of various heat treatments on transformation temperatures and electrical resistance properties of alloys from binary Cu-Mn system. It was noticed that with an increase in sample's grain size, transformation temperatures also increased. The activation energies of samples were calculated according to Kissinger and Augis-Bennett. Thermogravimetric and differential thermal analysis measurements were used to investigate phase transformations and kinetic parameters. The electrical values of resistance of alloy were investigated at different temperatures. The resistance as a function of quenching temperature showed a decrease. Depending on quenching techniques, Cu-Mn alloy can display different product phases such as parent phase and precipitation.

  4. Phase diagrams of aluminium alloys of Al-Cu-Mg, Al-Mg-Si-Cu, and Al-Mg-Li system

    International Nuclear Information System (INIS)

    Isothermal diagrams of phase transformations (DPT) and temperature-time charts (TTC) of variation of electric conductivity and of mechanical features at tension were plotted following thermal treatment according to the pattern of direct hardening and ageing and according to the pattern of normal aging for D16 commercial alloy, Al-Cu-Mg model alloy of the same system, AD37 commercial alloys of Al-Mg-Si-Cu and 1424 one of Al-Li-Mg system. Phase transformations were studied by means of fluorescence electron microscopy, micro-X-ray spectral analysis, X-ray phase analysis of single crystals and polycrystals and differential scanning calorimetry. For every alloy comparison of TTC and DPT enables to clarity the mechanism of phase composition effect on features and to optimize conditions of hardening cooling and ageing

  5. Improvements of welding characteristics of aluminum alloys with YAG laser and TIG arc hybrid system

    Science.gov (United States)

    Fujinaga, Shigeki; Ohashi, Ryoji; Katayama, Seiji; Matsunawa, Akira

    2003-03-01

    In high power YAG laser welding of steels, a rectangularly modulated beam with high peak power is usually used to get deep penetration. On the other hand, many spatters and solidification cracks are generated when some aluminum alloys are welded with a rectangularly modulated beam because of its high heat conductivity, high reflectivity, low surface tension, large contraction, wide solidification temperature range, etc. Therefore, a properly modulated beam or a continuous beam is usually used in aluminum alloy welding, although the penetration depth is shallow. In this research, sinusoidal wave or rectangularly modulated wave of YAG laser combined with TIG arc was tried to improve the weldability of A6061 aluminum alloy. As a result, when TIG arc was superimposed behind the YAG laser beam, deeply penetrated weld beads with good surface appearances were produced without spatter losses and cracks.

  6. High-temperature alloys and thermal spray coatings for energy conversion systems

    International Nuclear Information System (INIS)

    Materials continue to be of primary concern as the potential limiting factor for the implementation of coal gasification technology in Canada. Superalloys and thermal spray coatings for syngas coolers represent one class of materials where a knowledge of general trends in oxidation/sulphidation and erosion resistance for a range of chemical compositions is thought to be essential for reliable operation of such technology. Alloy 800H, 304, 310, T91, Monit and Sanicro 28 along with four types of coatings (Al2O3, Cr2O3, Al2O3/Ni3Al and CoCrAlYNi) applied on each one of the above alloys have been subjected to a series of exposures (6 x 250h cycles) in two different gas mixtures containing CO, H2, H2S, H2O at 600 C. The kinetics and mechanisms of corrosion and erosion of these alloys have been investigated using Scanning Electron Microscopy and surface analytical techniques. Thermal spray coatings of ceramic and composite materials were found to be problematic on austenitic alloys because of spallation. Ceramic, composite and metallic coatings adhered well to the ferritic alloy. Nickel aluminide in combination with aluminum oxide as a composite did not display the expected high degree of corrosion resistance. High temperature erosion rates were found to be low on the bare superalloys and to be decreased by highly alloyed metallic coatings such as CoCrAlYNi, FeCrAlYMo and NiCrAlYCo. Ceramic and composite coatings were ineffective in reducing erosion rates because of spallation and reactivity in the simulated gasification environment

  7. Low friction and wear resistant coating systems on Ti6Al4V alloy

    Directory of Open Access Journals (Sweden)

    B.G. Wendler

    2008-02-01

    Full Text Available Purpose: Development of an original multiplex hybrid treatment of Ti6Al4V alloy: diffusion hardening+intermediate hard gradient TiCxNy layer with use of continuous CAE+top low friction and wear resistant hard amorphous a-C layer with use of pulsed CAE method.Design/methodology/approach: Ti6Al4V substrates were diffusion hardened with interstitial O or N atoms with use of glow discharge plasma in the atmosphere Ar+O2 or Ar+N2. Next they were deposited with a hard gradient TiCxNy layer and with a hard amorphous a-C coating as the top one. The morphology, microstructure, chemical and phase composition, chemical bonds, microhardness and tribological properties during dry friction of the alloy after multiplex treatment have been investigated with use of SEM, EDS, XRD, XPS, Vickers diamond indenter and ball-on-plate test.Findings: An important increase of hardness of the near surface zone of the Ti6Al4V alloy has been achieved (from ~350VHN to ~1000 VHN, good adhesion between the gradient TiCxNy coating and the Ti6Al4V substrate as well as an important decrease of dry friction coefficient (down to ~0.15 and a substantial increase of the resistance to wear (up to two orders of magnitude in comparison with non treated Ti alloy.Research limitations/implications: The research will be continued on greater number of specimens and against other counterbodies.Practical implications: It looks like that the Ti alloys can be used as mobile parts of machines due to high resistance to wear and low friction.Originality/value: A novel original multiplex hybrid treatment of Ti alloys has been developed at the Lodz University of Technology.

  8. Effects of coolant chemistry on corrosion of 3003 aluminum alloy in automotive cooling system

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y.; Cheng, Y.F. [Department of Mechanical and Manufacturing Engineering, University of Calgary, Calgary, Alberta (Canada)

    2010-07-15

    In this work, effects of coolant chemistry, including concentrations of chloride ions and ethylene glycol and addition of various ions, on corrosion of 3003 Al alloy were investigated by electrochemical impedance spectroscopy measurements and scanning electron microscopy characterization. In chloride-free, ethylene glycol-water solution, a layer of Al-alcohol film is proposed to form on the electrode surface. With the increase of ethylene glycol concentration, more Al-alcohol film is formed, resulting in the increase in film resistance and charge-transfer resistance. In the presence of Cl{sup -} ions, they would be involved in the film formation, decreasing the stability of the film. In 50% ethylene glycol-water solution, the threshold value of Cl{sup -} concentration for pitting initiation is within the range of 100 ppm to 0.01 M. When the ethylene glycol concentration increases to 70%, the threshold Cl{sup -} concentration for pitting is from 0.01 to 0.1 M. In 100% ethylene glycol, there is no pitting of 3003 Al alloy even at 0.1 M of Cl{sup -}. Even a trace amount of impurity cation could affect significantly the corrosion behavior of 3003 Al alloy in ethylene glycol-water solution. Addition of Zn{sup 2+} is capable of increasing the corrosion resistance of Al alloy electrode, while Cu{sup 2+} ions containing in the solution would enhance corrosion, especially pitting corrosion, of Al alloy. The effect of Mg{sup 2+} on Al alloy corrosion is only slight. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  9. The Al-rich region of the Al–Fe–Mn alloy system

    International Nuclear Information System (INIS)

    Highlights: • Constitution of Al–Fe–Mn was studied above 50 at.% Al at 650–1070 °C. • AlMn (A2) and AlFe (B2) phases form a continuous compositional region. • Al8Mn5 and Al8Fe5 γ-brass type phases form a continuous compositional region. • Al13Fe4, Al5Fe2, Al2Fe, Al6Mn, Al11Mn4, γ2 exhibit wide ternary extensions. • Four ternary intermetallics were revealed. - Abstract: Phase equilibria in the Al-rich region of the Al–Fe–Mn alloy system were studied at 1070, 1020, 950, 875, 800, 740, 695 and 650 °C. The continuous region of the bcc solid solution was estimated between the Al–Mn and Al–Fe terminals. Also the isostructural high-temperature Al–Mn and Al–Fe γ1-phases (γ-brass type structure) form continuous regions. The Al6Mn, high-temperature T-Al11Mn4 and low-temperature γ2 phases dissolve up to 9.0, 14.5 and 31.0 at.% Fe, respectively, while the M-Al13Fe4, Al5Fe2 and Al2Fe phases dissolve up to 15.5, 11.5 and 10.0 at.% Mn, respectively. The thermodynamically stable decagonal D3-phase with periodicity of 1.25 nm in the specific direction and two periodic intermetallics designated φ (P63/mmc; a = 0.7554, c = 0.7872 nm) and κ (P63/m; a = 1.7630, c = 1.2506 nm) were identified. An additional ternary phase of unknown structure was also revealed

  10. Designing and Validating Ternary Pd Alloys for Optimum Sulfur/Carbon Resistance in Hydrogen Separation and Carbon Capture Membrane Systems Using High-Throughput Combinatorial Methods

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Amanda; Zhao, Hongbin; Hopkins, Scott

    2014-09-30

    This report summarizes the work completed under the U.S. Department of Energy Project Award No.: DE-FE0001181 titled “Designing and Validating Ternary Pd Alloys for Optimum Sulfur/Carbon Resistance in Hydrogen Separation and Carbon Capture Membrane Systems Using High-Throughput Combinatorial Methods.” The project started in October 1, 2009 and was finished September 30, 2014. Pall Corporation worked with Cornell University to sputter and test palladium-based ternary alloys onto silicon wafers to examine many alloys at once. With the specialized equipment at Georgia Institute of Technology that analyzed the wafers for adsorbed carbon and sulfur species six compositions were identified to have resistance to carbon and sulfur species. These compositions were deposited on Pall AccuSep® supports by Colorado School of Mines and then tested in simulated synthetic coal gas at the Pall Corporation. Two of the six alloys were chosen for further investigations based on their performance. Alloy reproducibility and long-term testing of PdAuAg and PdZrAu provided insight to the ability to manufacture these compositions for testing. PdAuAg is the most promising alloy found in this work based on the fabrication reproducibility and resistance to carbon and sulfur. Although PdZrAu had great initial resistance to carbon and sulfur species, the alloy composition has a very narrow range that hindered testing reproducibility.

  11. Effect of the substitutional elements on the microstructure of the Ti-15Mo-Zr and Ti-15Zr-Mo systems alloys

    OpenAIRE

    Diego Rafael Nespeque Correa; Fábio Bossoi Vicente; Raul Oliveira Araújo; Mariana Luna Lourenço; Pedro Akira Bazaglia Kuroda; Marília Afonso Rabelo Buzalaf; Carlos Roberto Grandini

    2015-01-01

    Titanium alloys have excellent biocompatibility, and combined with their low elastic modulus, become more efficient when applied in orthopedic prostheses. Samples of Ti-15Mo-Zr and Ti-15Zr-Mo system alloys were prepared using an arc-melting furnace with argon atmosphere. The chemical quantitative analysis was performed using an optical emission spectrometer with inductively coupled plasma and thermal conductivity difference. The X-ray diffractograms, allied with optical microscopy, revealed t...

  12. Electrochemical studies on La-Co alloy film in acetamide-urea-NaBr melt system

    Institute of Scientific and Technical Information of China (English)

    GUO Cheng-yu; WANG Jian-chao; CHEN Bi-qing; WANG Jing-gui

    2005-01-01

    The kinetics of La-Co alloy film in acetamide-urea-NaBr molten salt electrolyte at 353 K was investigated. It is shown that the reduction of Co( Ⅱ ) to Co is irreversible reaction with the transfer coefficient of 0.28 and the diffusion coefficient of 7.46 × 10-5cm2/s. While La( Ⅲ ) cannot be reduced to La directly; but can be codeposited with cobalt. The content of La in the uncrystallized La-Co alloy film increases with increasing cathodic overpotential, molar ratio of La3+ to Co2+ and electrolysis time as well, and reaches the maximum of 66.32%.

  13. Influence of milling container internal geometry on the mechanical alloying process of the Fe75Si15B10 system

    International Nuclear Information System (INIS)

    57Fe Moessbauer spectroscopy and X-ray diffraction were used to study the influence of container internal geometry (flat-endings or round-endings) on the mechanical alloying process of the Fe75Si15B10 system. The Moessbauer spectrum for the sample processed for 19 h in a round-endings container indicates the formation of an amorphous Fe-B-Si phase, with 96% of the Fe total volume. Oppositely, the alloy processed in a flat-endings container for 12 h has a spectrum with 82% of Fe atoms in nanocrystalline Fe,Si and Fe2B phases and the remaining 18% are dispersed at the disordered grain boundary region (amorphous state). This result suggests that a single phase alloy is hard to be obtained in this container. It is also shown that the samples processed in the flat-endings container can be de-mixed to α-Fe phase by milling at times above 18 h. The sample preparation procedures have been repeated twice in order to prove the results reproducibility

  14. Direct observation of the crystal structure changes in the MgxZn1−xO alloy system

    International Nuclear Information System (INIS)

    We directly observed the crystal structure changes of the MgxZn1−xO alloy thin film deposited on Si (111) substrates. Through the in situ heating transmission electron microscopy study, it was determined that the crystal structure changes did not occur up to at 400 °C, whereas the disappearance of the hexagonal structure was observed at 500 °C in the layer of nanosized grains. Additionally, the decreased intensity of the Zn L-edge was analyzed in the comparison of the core loss electron energy loss spectroscopy spectra of the Zn L-edge and the Mg K-edge obtained at room temperature and 500 °C. Based on these experimental results, the process of crystal structure changes could be explained by the evaporation of Zn atoms in the MgxZn1−xO alloy system. This phenomenon is prominent in the improvement of the microstructure of the MgxZn1−xO alloy thin film by controlling the thermal annealing temperature. - Highlights: • MgxZn1−xO thin films coexisting with cubic and hexagonal structures were deposited. • Crystal structure changes of the thin films were directly observed at 500 °C. • The process of microstructure changes could be caused by the evaporation of Zn atoms

  15. Gating system optimization of low pressure casting A356 aluminum alloy intake manifold based on numerical simulation

    Directory of Open Access Journals (Sweden)

    Jiang Wenming

    2014-03-01

    Full Text Available To eliminate the shrinkage porosity in low pressure casting of an A356 aluminum alloy intake manifold casting, numerical simulation on filling and solidification processes of the casting was carried out using the ProCAST software. The gating system of the casting is optimized according to the simulation results. Results show that when the gating system consists of only one sprue, the filling of the molten metal is not stable; and the casting does not follow the sequence solidification, and many shrinkage porosities are observed through the casting. After the gating system is improved by adding one runner and two in-gates, the filling time is prolonged from 4.0 s to 4.5 s, the filling of molten metal becomes stable, but this casting does not follow the sequence solidification either. Some shrinkage porosity is also observed in the hot spots of the casting. When the gating system was further improved by adding risers and chill to the hot spots of the casting, the shrinkage porosity defects were eliminated completely. Finally, by using the optimized gating system the A356 aluminum alloy intake manifold casting with integrated shape and smooth surface as well as dense microstructure was successfully produced.

  16. Welding of aluminum alloys through thermite like reactions in Al–CuO–Ni system

    International Nuclear Information System (INIS)

    Highlights: ► Combustion synthesis reactions were utilized for welding of aluminum alloys. ► A composite joint reinforced by different intermetallic compounds was obtained. ► Using metal oxides as a part of raw materials makes the welding process economical. ► Furthermore, this process introduces new applications for thermite reactions. - Abstract: In this work, first, a metastable composite powder of “14Al–3CuO–Ni” with a decreased ignition temperature was obtained via Arrested Reactive Milling (ARM), then this exothermic blend was used for welding of 1100 Aluminum alloy. The reactive media and the weld zones were investigated using scanning electron microscope. X-ray diffraction experiment and morphological investigations accompanied with the EDS analyses were carried out in order to evaluate the reactions’ products. Vickers microhardness profile across the joint and the shear strength of the joints were determined. The weld zone thickness in each of the parent alloys was measured to be 750 μm, approximately. Results showed that different reactions occurring during the process lead to the in situ formation of different intermetallic compounds such as Al3Ni2 and Al7Cu4Ni as well as Al2O3 nanoparticles at the interface. Thus, this area has the maximum hardness (80–90 VHN) and the minimum hardness of 35 VHN belongs to the parent alloys. The mean shear strength of the obtained joints was 27 MPa.

  17. Development of High-Temperature Ferritic Alloys and Performance Prediction Methods for Advanced Fission Energy Systems

    Energy Technology Data Exchange (ETDEWEB)

    G. RObert Odette; Takuya Yamamoto

    2009-08-14

    Reports the results of a comprehensive development and analysis of a database on irradiation hardening and embrittlement of tempered martensitic steels (TMS). Alloy specific quantitative semi-empirical models were derived for the dpa dose, irradiation temperature (ti) and test (Tt) temperature of yield stress hardening (or softening) .

  18. A thermodynamic approach to energy storage on mechanical alloying of the Cu-Cr system

    International Nuclear Information System (INIS)

    The object of this work is to estimate the increase in new surface and elastic energy during mechanical alloying of Cu-Cr powders processed by means of a SPEX mill in comparison with a regular solution model. The presence of crystalline defects increases the Gibbs free energy and the Gibbs free energy curves are moved upwards; hence the solubility limit changes

  19. Peculiarities of structure formation of layered metal-oxide system Ti-Ta-(Ti,Ta)xOy during electro-spark alloying and thermally stimulated modification

    Science.gov (United States)

    Fomina, Marina A.; Koshuro, Vladimir A.; Fomin, Aleksandr A.; Rodionov, Igor V.; Skaptsov, Aleksandr A.; Zakharevich, Andrey M.; Aman, Alexander; Oseev, Aleksandr; Hirsch, Soeren; Majcherek, Soeren

    2016-04-01

    The study focuses on high-performance combined electro-spark alloying of titanium and titanium alloy (VT1-0, VT16) surface and porous matrix structure oxidation. The metal-oxide coatings morphology is the result of melt drop transfer, heat treatment, and oxidation. The study establishes the influence of technological regimes of alloying and oxidation on morphological heterogeneity of biocompatible layered metal-oxide system Ti-Ta-(Ti,Ta)xOy. It was found that during electro-spark alloying the concentration of tantalum on the titanium surface ranges from 0.1 to 3.2 at.%. Morphology of the deposited splats is represented by uniformly grown crystals of titanium and tantalum oxides, which increase from nano- to submicron size.

  20. Evaluation of austenitic alloys abrasive wear of FeMnAlC system; Avaliacao de desgaste abrasivo de ligas austeniticas do sistema FeMnAlC

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Allan Ribeiro de; Acselrad, Oscar [Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Metalurgica e de Materiais. Lab. de Processamento Termomecanico e Engenharia Microestrutural]. E-mail: allariba@metalmat.ufrj.br

    2003-07-01

    Alloys of the FeMnAlC system have been studied as an alternative to stainless steels applications. Such alloys, when solubilized, are non-magnetic and present an austenitic structure that can be modified by thermal treatments. In this way, a large spectrum of mechanical and physical properties can be obtained. They are oxidation-resistant alloys, and by 15 hours aging at 550 deg C mechanical strength can be as high as conventional structural alloy steels. Information concerning the performance of these alloys under wear conditions are still limited. The possibility of application in components exposed to cavitation or abrasive loads, such as pipes, pumps and drilling systems is still a subject for fundamental research, such as the one that is now reported. Samples of a FeMnAlC alloy have been submitted to different thermal processing, leading to microstructures that have been characterized by optical, transmission and atomic force microscopy and by X-ray diffraction. They were subsequently subjected to a micro-abrasion test in which the abrasive wear resistance could be determined. The results have been used to differentiate the performance of different microstructures and allowed also a comparative analysis with the performance of an AISI M2 tool steel. (author)

  1. The effect of silicon on the wettability and interfacial reaction in AlN/Cu alloy systems

    International Nuclear Information System (INIS)

    Wetting behavior of AlN by Cu alloys has been studied in vacuum through sessile drop technique. The contact angle was determined by high temperature photography and shape analysis software. Pure copper does not wet AlN. The contact angle of the AlN/Cu system at 1200 deg. C is 138 deg. Adding 20 at% Si leads to the decrease of the contact angle from 138 deg. to 96 deg., and a reaction layer forms in the interfacial area. The addition of Si can also improve the wettability of AlN/Cu10Ti (the atomic ratio of Cu:Ti is 90:10) system. The contact angle of the system decreases to the values less than 20 deg. at 1200 deg. C by adding 20 at% or 27 at% Si. During the wetting experiment, Ti diffuses to and reacts with AlN, leading to the formation of TiN. Addition of Si can retard the reaction between Ti and AlN by forming a Si-rich layer, mainly composed of Ti-Si compound, between the reaction layer, mainly composed of TiN, and the CuSiTi alloy. The Si-rich layer also contributes to the improvement of the wettability of the system. In the meantime, the addition of Si contributes to the decrease of the stress in the interfacial area and to the bonding at the interfaces.

  2. Assessment of the transmutation capability an accelerator driven system cooled by lead bismuth eutectic alloy

    International Nuclear Information System (INIS)

    1. PURPOSE The reduction of long-lived fission products (LLFP) and minor actinides (MA) is a key point for the public acceptability and economy of nuclear energy. In principle, any nuclear fast reactor is able to burn and transmute MA, but the amount of MA content has to be limited a few percent, having unfavourable consequences on the coolant void reactivity, Doppler effect, and delayed neutron fraction, and therefore on the dynamic behaviour and control. Accelerator Driven Systems (ADS) are instead able to safely burn and/or transmute a large quantity of actinides and LLFP, as they do not rely on delayed neutrons for control or power change and the reactivity feedbacks have very little importance during accidents. Such systems are very innovative being based on the coupling of an accelerator with a subcritical system by means of a target system, where the neutronic source needed to maintain the neutron reaction chain is produced by spallation reactions. To this end the PDS-XADS (Preliminary Design Studies on an experimental Accelerator Driven System) project was funded by the European Community in the 5th Framework Program in order both to demonstrate the feasibility of the coupling between an accelerator and a sub-critical core loaded with standard MOX fuel and to investigate the transmutation capability in order to achieve values suitable for an Industrial Scale Transmuter. This paper summarizes and compares the results of neutronic calculations aimed at evaluating the transmutation capability of cores cooled by Lead-Bismuth Eutectic alloy and loaded with assemblies based on (Pu, Am, Cm) oxide dispersed in a molybdenum metal (CERMET) or magnesia (CERCER) matrices. It also describes the constraints considered in the design of such cores and describes the thermo-mechanical behaviour of these innovative fuels along the cycle. 2. DESCRIPTION OF THE WORK: The U-free composite fuels (CERMET and CERCER) were selected for this study, being considered at European level

  3. Ab initio simulations of liquid systems Concentration dependence of the electric conductivity of NaSn alloys

    CERN Document Server

    Kaschner, R; Seifert, G; Pastore, G

    1996-01-01

    Liquid NaSn alloys in five different compositions (20, 40, 50, 57 and 80% sodium) are studied using density functional calculations combined with molecular dynamics(Car-Parrinello method). The frequency-dependent electric conductivities for the systems are calculated by means of the Kubo-Greenwood formula. The extrapolated DC conductivities are in good agreement with the experimental data and reproduce the strong variation with the concentration. The maximum of conductivity is obtained, in agreement with experiment, near the equimolar composition. The strong variation of conductivity, ranging from almost semiconducting up to metallic behaviour, can be understood by an analysis of the densities-of-states.

  4. Isothermal compressibility and some elastic properties of TlInS2-TlGdS2 system alloys

    International Nuclear Information System (INIS)

    Temperature dependence of isothermal compression coefficient in alloys of the TlInS2-TlGdS2 system was studied. An anomaly was revealed, which was related to the second type phase transition. It is ascertained that with the growth of gadolinium atom content in TlIn1-xGdxS2 elasticity parameters: the Young modulus, shear modulus, the Poisson ratio and longitudinal velocity of ultrasonic waves - increase, which is in all probability explained by chemical bond weakening

  5. The Al-rich region of the Al–Fe–Mn alloy system

    Energy Technology Data Exchange (ETDEWEB)

    Balanetskyy, S. [IMF-IFF, Forschungszentrum Jülich, D-52425 Jülich (Germany); Department of Physical Chemistry of Inorganic Materials, I.N. Frantsevich Institute for Problems of Materials Science, 03680 Kyiv 142 (Ukraine); Pavlyuchkov, D. [Department of Physical Chemistry of Inorganic Materials, I.N. Frantsevich Institute for Problems of Materials Science, 03680 Kyiv 142 (Ukraine); Institute of Materials Science, Technical University of Freiberg, D-09599 Freiberg (Germany); Velikanova, T. [Department of Physical Chemistry of Inorganic Materials, I.N. Frantsevich Institute for Problems of Materials Science, 03680 Kyiv 142 (Ukraine); Grushko, B., E-mail: b.grushko@fz-juelich.de [PGI-5, Forschungszentrum Jülich, D-52425 Jülich (Germany)

    2015-01-15

    Highlights: • Constitution of Al–Fe–Mn was studied above 50 at.% Al at 650–1070 °C. • AlMn (A2) and AlFe (B2) phases form a continuous compositional region. • Al{sub 8}Mn{sub 5} and Al{sub 8}Fe{sub 5} γ-brass type phases form a continuous compositional region. • Al{sub 13}Fe{sub 4}, Al{sub 5}Fe{sub 2}, Al{sub 2}Fe, Al{sub 6}Mn, Al{sub 11}Mn{sub 4}, γ{sub 2} exhibit wide ternary extensions. • Four ternary intermetallics were revealed. - Abstract: Phase equilibria in the Al-rich region of the Al–Fe–Mn alloy system were studied at 1070, 1020, 950, 875, 800, 740, 695 and 650 °C. The continuous region of the bcc solid solution was estimated between the Al–Mn and Al–Fe terminals. Also the isostructural high-temperature Al–Mn and Al–Fe γ{sub 1}-phases (γ-brass type structure) form continuous regions. The Al{sub 6}Mn, high-temperature T-Al{sub 11}Mn{sub 4} and low-temperature γ{sub 2} phases dissolve up to 9.0, 14.5 and 31.0 at.% Fe, respectively, while the M-Al{sub 13}Fe{sub 4}, Al{sub 5}Fe{sub 2} and Al{sub 2}Fe phases dissolve up to 15.5, 11.5 and 10.0 at.% Mn, respectively. The thermodynamically stable decagonal D{sub 3}-phase with periodicity of 1.25 nm in the specific direction and two periodic intermetallics designated φ (P6{sub 3}/mmc; a = 0.7554, c = 0.7872 nm) and κ (P6{sub 3}/m; a = 1.7630, c = 1.2506 nm) were identified. An additional ternary phase of unknown structure was also revealed.

  6. Thermodynamic Measurements on Alloys and Compounds in Ag-Au-Se and Ag-Pd systems by the Electromotive Force Method

    OpenAIRE

    Feng, Dawei

    2014-01-01

    Gold and silver chalcogenides are significant minerals and major carriers of precious metals, and silver palladium alloy is one of the most important silver alloys with various industrial applications. The Ag-Au-Se ternary system and the Ag-Pd binary system have been investigated by the electromotive force (EMF) method in this study. For the Ag-Au-Se ternary system, the numerical values of the standard thermodynamic functions of the compounds Ag2Se (naumannite), AuSe, and Ag3AuSe2 (fisches...

  7. Injection Molding of Titanium Alloy Implant For Biomedical Application Using Novel Binder System Based on Palm Oil Derivatives

    Directory of Open Access Journals (Sweden)

    R. Ibrahim

    2010-01-01

    Full Text Available Problem statement: Titanium alloy (Ti6Al4V has been widely used as an implant for biomedical application. In this study, the implant had been fabricated using high technology of Powder Injection Molding (PIM process due to the cost effective technique for producing small, complex and precision parts in high volume compared with conventional method through machining. Approach: Through PIM, the binder system is one of the most important criteria in order to successfully fabricate the implants. Even though, the binder system is a temporary, but failure in the selection and removal of the binder system will affect on the final properties of the sintered parts. Therefore, the binder system based on palm oil derivative which is palm stearin had been formulated and developed to replace the conventional binder system. Results: The rheological studies of the mixture between the powder and binders system had been determined properly in order to be successful during injection into injection molding machine. After molding, the binder held the particles in place. The binder system had to be removed completely through debinding step. During debinding step, solvent debinding and thermal pyrolysis had been used to remove completely of the binder system. The debound part was then sintered to give the required physical and mechanical properties. The in vitro biocompatibility also was tested using Neutral Red (NR and mouse fibroblast cell lines L-929 for the direct contact assay. Conclusion: The results showed that the properties of the final sintered parts fulfill the Standard Metal Powder Industries Federation (MPIF 35 for PIM parts except for tensile strength and elongation due to the formation of titanium carbide. The in vitro biocompatibility on the extraction using mouse fibroblast cell line L-929 by means of NR assays showed non toxic for the sintered specimen titanium alloy parts.

  8. Hydrogen effect on shear modulus in TiNi-TiCu system quasibinary alloys

    International Nuclear Information System (INIS)

    The study on the quick-quenched films of the Ti50Ni25Cu25 alloys, 40-60 μm thick, saturated with hydrogen through the electrolytic facility is carried out. The crystalline, amorphous or amorphous-crystalline states were obtained in dependence on the melt cooling rate. The shear modulus was measured through the method of the torsion oscillations on the 1 Hz order frequencies. Sharp decrease in the modulus shear in the amorphous alloys was noted in the hydrogen saturation process. The conclusion is made that the observed effect is not connected with the origination of new phase and structural constituents by the hydrogen saturation and it may be explained by its superequilibrium concentration

  9. Welding of aluminum alloys through thermite like reactions in Al-CuO-Ni system

    Energy Technology Data Exchange (ETDEWEB)

    Bahrami Motlagh, Ehsan, E-mail: ehsan.bahramimotlagh@stu-mail.um.ac.ir [Department of Materials Science and Engineering, Engineering Faculty, Ferdowsi University of Mashhad, P.O. Box 9177948944, Mashhad (Iran, Islamic Republic of); Vahdati Khaki, Jalil; Haddad Sabzevar, Mohsen [Department of Materials Science and Engineering, Engineering Faculty, Ferdowsi University of Mashhad, P.O. Box 9177948944, Mashhad (Iran, Islamic Republic of)

    2012-04-16

    Highlights: Black-Right-Pointing-Pointer Combustion synthesis reactions were utilized for welding of aluminum alloys. Black-Right-Pointing-Pointer A composite joint reinforced by different intermetallic compounds was obtained. Black-Right-Pointing-Pointer Using metal oxides as a part of raw materials makes the welding process economical. Black-Right-Pointing-Pointer Furthermore, this process introduces new applications for thermite reactions. - Abstract: In this work, first, a metastable composite powder of '14Al-3CuO-Ni' with a decreased ignition temperature was obtained via Arrested Reactive Milling (ARM), then this exothermic blend was used for welding of 1100 Aluminum alloy. The reactive media and the weld zones were investigated using scanning electron microscope. X-ray diffraction experiment and morphological investigations accompanied with the EDS analyses were carried out in order to evaluate the reactions' products. Vickers microhardness profile across the joint and the shear strength of the joints were determined. The weld zone thickness in each of the parent alloys was measured to be 750 {mu}m, approximately. Results showed that different reactions occurring during the process lead to the in situ formation of different intermetallic compounds such as Al{sub 3}Ni{sub 2} and Al{sub 7}Cu{sub 4}Ni as well as Al{sub 2}O{sub 3} nanoparticles at the interface. Thus, this area has the maximum hardness (80-90 VHN) and the minimum hardness of 35 VHN belongs to the parent alloys. The mean shear strength of the obtained joints was 27 MPa.

  10. Structural analysis and magnetic properties of solid solutions of Co–Cr system obtained by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Betancourt-Cantera, J.A. [Área Académica de Ciencias de la Tierra y Materiales, UAEH Carr., Pachuca-Tulancingo Km. 4.5, Pachuca, Hidalgo 42184 (Mexico); Sánchez-De Jesús, F., E-mail: fsanchez@uaeh.edu.mx [Área Académica de Ciencias de la Tierra y Materiales, UAEH Carr., Pachuca-Tulancingo Km. 4.5, Pachuca, Hidalgo 42184 (Mexico); Bolarín-Miró, A.M. [Área Académica de Ciencias de la Tierra y Materiales, UAEH Carr., Pachuca-Tulancingo Km. 4.5, Pachuca, Hidalgo 42184 (Mexico); Betancourt, I.; Torres-Villaseñor, G. [Departamento de Materiales Metálicos y Cerámicos, Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, México D.F. 04510 (Mexico)

    2014-03-15

    In this paper, a systematic study on the structural and magnetic properties of Co{sub 100−x}Cr{sub x} alloys (0alloying is presented. Co and Cr elemental powders were used as precursors, and mixed in an adequate weight ratio to obtain Co{sub 1−x}Cr{sub x} (0alloying (MA) induces the formation of solid solutions of Co–Cr system in non-equilibrium. • We report the crystal structure and the magnetic behavior of Co–Cr alloys produced by MA. • MA improves the magnetic properties of Co–Cr system.

  11. In situ X-ray Diffraction Study of Ni–Yb Interlayer and Alloy Systems on Si„100

    Energy Technology Data Exchange (ETDEWEB)

    Knaepen, W.; Demeulemeester, J; Jordan-Sweet, J; Vantomme, A; Detavernier, C; Van Meirhaeghe, R; Lavoie, C

    2010-01-01

    The phase formation in the ternary Ni/Yb/Si system was studied for Ni-Yb alloy and interlayer structures on Si(100) substrates using in situ x-ray diffraction measurements. Yb was treated as an alloying element in the Ni-Si system with Yb concentrations varying between 0 and 40 at. % of the Ni concentration. Independent of the initial structure of the sample, a Ni-Si or Ni-Yb compound was detected first which suggests that Ni is the dominant diffusing species during the solid state reactions. No pure Yb silicides were identified but a ternary phase (YbNi{sub 2}Si{sub 2}) formed in all samples after the Si atoms became mobile. Information about the distribution of the phases throughout the thin silicide film was obtained using ex situ Rutherford backscattering analysis. Independent of the Yb concentration, the NiSi phase formed at the substrate interface. As a result, the immobile Yb atoms shifted toward the sample surface and no detectable amount of Yb atoms was left at the Ni-silicide/Si interface after annealing.

  12. Mechanical properties and biocompatibility in alloy Ti-Ta system containing oxygen; Propriedades mecanicas e biocompatibilidades em ligas do sistema Ti-Ta contendo oxigenio

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, S.L.M.; Grandini, C.R., E-mail: samlea@fc.unesp.b [Universidade Estadual Paulista (UNESP), Bauru, SP (Brazil). Lab. de Anelasticidade e Biomateriais; Claro, A.P.R.A. [Universidade Estadual Paulista Julio de Mesquisa Filho (DMT/UNESP), Guaratingueta, SP (Brazil). Fac. de Engenharia. Dept. de Materiais e Tecnologia

    2010-07-01

    Due to the excellent properties such as corrosion resistance, good mechanical strength/density, good performance at high temperatures, Ti is very useful in the chemical industry and aerospace. Currently, their use has expanded to the field of biomaterials, due to its excellent biocompatibility and reduced elasticity modulus, favouring the production of orthopaedic and dental prostheses. Promising alloys are the Ti-Ta system and researches have been directed to describe and understand the behavior of this system. In this paper, samples of Ti-Ta alloys containing 8 and 16% (wt%) containing interstitial oxygen were prepared and characterized by density, xray diffraction, hardness, elasticity modulus measurements and in vitro cytotoxicity tests. (author)

  13. Magnetic losses and their relation with coercive force in Co80(Cr,Mo)10Zr10 system amorphous alloys with near-zero magnetostriction

    International Nuclear Information System (INIS)

    Co80Cr10-xMoxZr10 system amorphous alloys where x=0,2,8 and 10 at.% Mo were studied. In general case similar dependence of P and Hc magnetic losses on annealing temperature is shown to b absent in Co80(Cr, Mo)10Zr10 system alloys. Uniformity of P and Hc variation is observed in the annealing temperature range where predominant relaxation process simultaneous by affects both P and H, or when single-type variations of P and Hc is caused by different processes, but affecting P and Hc in the same direction. 11 refs., 5 figs

  14. Transmission electron microscopy studies of mechanical alloying in the immiscible a-Fe2O3-SnO2 system

    DEFF Research Database (Denmark)

    Rickerby, D.G.; Jiang, Jianzhong; Lin, R.; Mørup, Steen

    Microstructural development and nanoscale compositional variations in mechanically alloyed Fe2O3-SnO2 powders have been examined by transmission electron microscopy and energy dispersive X-ray spectrometry. The mean grain size was found to stabilize around 10 nm after 19 h milling time, in close......, indicating that a supersaturated solid solution is formed, but that mixing may be locally inhomogeneous at the atomic level. Similar conclusions have been reported for studies of mechanical alloying in immiscible metallic systems. The tendency for SnO2 grains above a certain critical size to remain...... relation to precious measurements in the same system by X-ray diffraction and Mossbauer spectroscopy, which suggested that alloying on the atomic scale occurred after 110 h milling. The present studies confirm that the amount of Sn dissolved in the Fe2O3 hematite lattice increases with longer milling times...

  15. Interphase thermodynamic bond in heterogeneous alloys: effects on alloy properties

    International Nuclear Information System (INIS)

    Inconsistency between a conventional thermodynamic description of alloys as a mechanical mixture of phases and a real alloys state as a common thermodynamic system in which there is a complicated physical-chemical phases interaction has been considered. It is supposed that in heterogeneous alloys (eutectic ones, for instance), so called interphase thermodynamic bond can become apparent due to a partial electron levels splitting under phase interaction. Thermodynamic description of phase equilibrium in alloys is proposed taking into account a thermodynamic bond for the system with phase diagram of eutectic type, and methods of the value of this bond estimation are presented. Experimental evidence (Al-Cu-Si, Al-Si-Mg-Cu, U-Mo + Al) of the effect of interphase thermodynamic bond on temperature and enthalpy of melting of alloys are produced as well as possibility of its effects on alloys electrical conduction, strength, heat and corrosion resistance is substantiated theoretically

  16. Precipitation of K phase in austenitic alloys of Fe-Mn-Al system

    International Nuclear Information System (INIS)

    The kinetics of austenite decomposition in a fully austenitic Fe-Mn-Al-Si-C alloy aged for up to 400 hours at 500, 550, 600 and 6500C was investigated. Mettalographic studies using optical and scanning electron microscopy, microprobe analysis and X-ray diffraction showed the presence only of the K-phase in the aged samples. Ferrite and other phases such as β-Mn were not detected at the aging temperatures employed. The activation energy for the K phase precipitation was evaluated by means of the evaluation of hardness peaks associated to the early stages of precipitation. (author)

  17. Low friction and wear resistant coating systems on Ti6Al4V alloy

    OpenAIRE

    Wendler, B.G.; W. Pawlak

    2008-01-01

    Purpose: Development of an original multiplex hybrid treatment of Ti6Al4V alloy: diffusion hardening+intermediate hard gradient TiCxNy layer with use of continuous CAE+top low friction and wear resistant hard amorphous a-C layer with use of pulsed CAE method.Design/methodology/approach: Ti6Al4V substrates were diffusion hardened with interstitial O or N atoms with use of glow discharge plasma in the atmosphere Ar+O2 or Ar+N2. Next they were deposited with a hard gradient TiCxNy layer and with...

  18. Integration of Shape Memory Alloys into Low-Damped Rotor-Bearing Systems

    DEFF Research Database (Denmark)

    Enemark, Søren

    2015-01-01

    to use passive adaptive control through smart materials. Shape Memory Alloys (SMAs) are interesting candidates in that relation, because of their highly temperature sensitive stiffness and mechanical hysteresis, which can be used for damping purposes. The thesis focuses on three main aspects related...... physical validity and identifiability, and to call attention to the inherent uncertainties of model predictions. The second aspect concerns design and modelling of machine elements made from SMAs. Different actuation principles of SMAs are covered, and pseudoelastic elements in pre-tension are found to...

  19. Phase Transformations in Low-Fe Alloys of the Al-Cu-Fe System

    Institute of Scientific and Technical Information of China (English)

    Liming Zhang

    2004-01-01

    Microstructure and phase transformation in the Al-Cu-Fe alloys of the approximate compositional range of 20 -50 at.% Cu and 2 - 10 Fe at.% have been investigated from samples quenched from their respective temperatures by means of different thermal analysis, magnetothermal analysis, scanning electron microscopy, electron probe analysis and powder X-ray diffraction. Representative phase transformations categorized as polymorphic, discontinuous precipitation,quasi-binary eutectoid, and ternary transitional U-type phase transformation are presented. These phase transformations were found to have a common feature which consumes the β phase and appears the φ phase. A schematic diagram was proposed to demonstrate the transition processes with decreasing temperature.

  20. Creep-resistant, cobalt-free alloys for high temperature, liquid-salt heat exchanger systems

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, David E; Muralidharan, Govindarajan; Wilson, Dane F.

    2016-09-06

    An essentially Fe- and Co-free alloy is composed essentially of, in terms of weight percent: 6.0 to 7.5 Cr, 0 to 0.15 Al, 0.5 to 0.85 Mn, 11 to 19.5 Mo, 0.03 to 4.5 Ta, 0.01 to 9 W, 0.03 to 0.08 C, 0 to 1 Re, 0 to 1 Ru, 0 to 0.001 B, 0.0005 to 0.005 N, balance Ni, the alloy being characterized by, at 850.degree. C., a yield strength of at least 25 Ksi, a tensile strength of at least 38 Ksi, a creep rupture life at 12 Ksi of at least 25 hours, and a corrosion rate, expressed in weight loss [g/(cm.sup.2 sec)]10.sup.-11 during a 1000 hour immersion in liquid FLiNaK at 850.degree. C., in the range of 3 to 10.

  1. Contributions on degradation kinetics of some alloys in cooling water systems of CANDU NPP

    International Nuclear Information System (INIS)

    Service lifetime of nuclear components may be limited indirectly by oxidation. The heat transport circuits of nuclear power plant have different water chemistry, corrosion products sources, temperatures and flow rates and these parameters can promote the growth and deposition of oxides with different composition on the surface of the nuclear steam generator tubes. Corrosion resistance of alloys in high temperature water of steam generator secondary circuit is related closely to the oxide films developed on their surfaces. The corrosion tests have been developed and conducted in order to investigate the characteristics of the oxide films formed on alloy 800, stainless steel 304L and carbon steel SA 516 in steam generator primary and secondary environments. The oxide films were formed by static autoclavization in simulated secondary environment solution (demineralized water with volatile amine treatment, T=260 deg C and p=5.1 MPa) and in primary environment solution (demineralized water with LiOH ,T=310 deg C and p=9 MPa). The characterization of the oxide films was done by metallographic microscopy and electrochemical methods. Based on these techniques were established correlations between oxidation kinetics and main characteristics of the oxide films. (author)

  2. Phase-field modelling of rapid solidification in alloy systems: Spontaneous grain refinement effects

    Science.gov (United States)

    Mullis, A. M.

    2012-07-01

    Phase-field modelling of rapid alloy solidification, in which the rejection of latent heat from the growing solid cannot be ignored, has lagged significantly behind the modelling of conventional casting practises which can be approximated as isothermal. This is in large part due to the fact that if realistic materials properties are adopted the ratio of the thermal to solute diffusivity (the Lewis number) is typically 103 - 104, leading to severe multi-scale problems. However, use of state-of-the-art numerical techniques such as local mesh adaptivity, implicit time-stepping and a non-linear multi-grid solver allow these difficulties to be overcome. Here we describe how the application of this model, formulated in the thin-interface limit, can help to explain the long-standing phenomenon of spontaneous grain refinement in deeply undercooled melts. We find that at intermediate undercoolings the operating point parameter, σ*, may collapse to zero, resulting in the growth of non-dendritic morphologies such as doublons and 'dendritic seaweed'. Further increases in undercooling then lead to the re-establishment of stable dendritic growth. We postulate that remelting of such seaweed structures gives rise to the low undercooling instance of grain refinement observed in alloys.

  3. Phase-field modelling of rapid solidification in alloy systems: Spontaneous grain refinement effects

    International Nuclear Information System (INIS)

    Phase-field modelling of rapid alloy solidification, in which the rejection of latent heat from the growing solid cannot be ignored, has lagged significantly behind the modelling of conventional casting practises which can be approximated as isothermal. This is in large part due to the fact that if realistic materials properties are adopted the ratio of the thermal to solute diffusivity (the Lewis number) is typically 103 - 104, leading to severe multi-scale problems. However, use of state-of-the-art numerical techniques such as local mesh adaptivity, implicit time-stepping and a non-linear multi-grid solver allow these difficulties to be overcome. Here we describe how the application of this model, formulated in the thin-interface limit, can help to explain the long-standing phenomenon of spontaneous grain refinement in deeply undercooled melts. We find that at intermediate undercoolings the operating point parameter, σ*, may collapse to zero, resulting in the growth of non-dendritic morphologies such as doublons and 'dendritic seaweed'. Further increases in undercooling then lead to the re-establishment of stable dendritic growth. We postulate that remelting of such seaweed structures gives rise to the low undercooling instance of grain refinement observed in alloys.

  4. System integration and demonstration of adhesive bonded high temperature aluminum alloys for aerospace structure, phase 2

    Science.gov (United States)

    Falcone, Anthony; Laakso, John H.

    1993-01-01

    Adhesive bonding materials and processes were evaluated for assembly of future high-temperature aluminum alloy structural components such as may be used in high-speed civil transport aircraft and space launch vehicles. A number of candidate high-temperature adhesives were selected and screening tests were conducted using single lap shear specimens. The selected adhesives were then used to bond sandwich (titanium core) test specimens, adhesive toughness test specimens, and isothermally aged lap shear specimens. Moderate-to-high lap shear strengths were obtained from bonded high-temperature aluminum and silicon carbide particulate-reinforced (SiC(sub p)) aluminum specimens. Shear strengths typically exceeded 3500 to 4000 lb/in(sup 2) and flatwise tensile strengths exceeded 750 lb/in(sup 2) even at elevated temperatures (300 F) using a bismaleimide adhesive. All faceskin-to-core bonds displayed excellent tear strength. The existing production phosphoric acid anodize surface preparation process developed at Boeing was used, and gave good performance with all of the aluminum and silicon carbide particulate-reinforced aluminum alloys investigated. The results of this program support using bonded assemblies of high-temperature aluminum components in applications where bonding is often used (e.g., secondary structures and tear stoppers).

  5. Exact electronic spectra and inverse localization lengths in one-dimensional random systems I. Random alloy, liquid metal and liquid alloy

    Science.gov (United States)

    Nieuwenhuizen, T. M.

    1983-07-01

    Analytic continuations into the complex energy plane of Dyson-Schmidt type of equations for the calculation of the density of states are constructed for a random alloy model, a liquid metal and for a liquid alloy. In all these models the characteristic function follows from the solution of this equation. Its imaginary part yields the accumulated density of states and its real part is a measure for the inverse of the localization length of the eigenfunctions. The equations have been solved exactly for some distributions of the random variables. In the random alloy case the strengths of the delta-potentials have an exponential distribution. They may also have finite, exponentially distributed values with probability 0 ⪕ p ⪕ 1 and be infinite with probability q = 1 - p. In the liquid metal the liquid particles are assumed to behave like hard rods. This implies an exponential distribution of the distances between the particles. The common electronic potential may be arbitrary, but is assumed to vanish outside the rods. In the one-dimensional liquid alloy there is, apart from positional randomness of the liquid particles, a distribution of the strengths of the electronic delta-potentials. For Cauchy distributions an argument of Lloyd is extended to obtain the characteristic function from the one in the model with equal strengths. For the case of a liquid of point particles a three parameter class of distributions of the strengths is shown to yield a solution in the form of known functions of the equation mentioned above. For several cases numerical calculations of the density of states and the inverse localization length of the eigenfunctions are presented and discussed. New results are found: exponential decay of the density of states near special energies in the random alloy and liquid metal; divergence of the density of states at certain energies with non-classical exponent {1}/{3} in the random alloy if the average of the potential strengths vanishes

  6. Creep Behavior of High Temperature Alloys for Generation IV Nuclear Energy Systems

    Science.gov (United States)

    Wen, Xingshuo

    The Very High Temperature Reactor (VHTR) is one of the leading concepts of the Generation IV nuclear reactor development, which is the core component of Next Generation Nuclear Plant (NGNP). The major challenge in the research and development of NGNP is the performance and reliability of structure materials at high temperature. Alloy 617, with an exceptional combination of high temperature strength and oxidation resistance, has been selected as a primary candidate material for structural use, particularly in Intermediate Heat Exchanger (IHX) which has an outlet temperature in the range of 850 to 950°C and an inner pressure from 5 to 20MPa. In order to qualify the material to be used at the operation condition for a designed service life of 60 years, a comprehensive scientific understanding of creep behavior at high temperature and low stress regime is necessary. In addition, the creep mechanism and the impact factors such as precipitates, grain size, and grain boundary characters need to be evaluated for the purpose of alloy design and development. In this study, thermomechanically processed specimens of alloy 617 with different grain sizes were fabricated, and creep tests with a systematic test matrix covering the temperatures of 850 to 1050°C and stress levels from 5 to 100MPa were conducted. Creep data was analyzed, and the creep curves were found to be unconventional without a well-defined steady-state creep. Very good linear relationships were determined for minimum creep rate versus stress levels with the stress exponents determined around 3-5 depending on the grain size and test condition. Activation energies were also calculated for different stress levels, and the values are close to 400kJ/mol, which is higher than that for self-diffusion in nickel. Power law dislocation climb-glide mechanism was proposed as the dominant creep mechanism in the test condition regime. Dynamic recrystallization happening at high strain range enhanced dislocation climb and

  7. Nuclear Magnetic Resonance Study of the Unconventional Kondo Alloy System Uranium COPPER(5-X) Palladium(x)

    Science.gov (United States)

    Bernal, Oscar Orlando

    The intermetallic Kondo alloy system UCu _{5-x}Pd_{x } is one of a number of recently-discovered Kondo materials which exhibit deviations from Fermi liquid behavior in their thermodynamic and transport properties down to micro-Kelvin temperatures. Studying local electronic structure by nuclear magnetic resonance techniques (NMR) in this unconventional system, we find anomalous behavior of NMR parameters versus magnetic susceptibility chi in UCu_4Pd and UCu_{3.5}Pd_ {1.5}. Metallic alloys containing magnetic impurities usually display a linear relation between the susceptibility and the Knight shift and its distribution, the magnetic broadening. In UCu_{5 -x}Pd_{x}, as the temperature is lowered, it is found that for both concentrations the magnetic broadening of the ^{63}Cu NMR spectra grows non-linearly with respect to chi, reaching enhancements at the lowest temperatures of ~100% over the values expected from a high-temperature linear relation. Enhancement of the linewidth over the susceptibility might indicate the possibility of U-spin freezing, as observed in some dilute Kondo alloys. The absence of any anomalies in either the specific heat or the magnetic susceptibility of these samples suggests, however, that spin freezing does not account for the observations, and that the enhancement is related to intrinsic behavior of the paramagnetic alloys. Smaller but similar anomalies are found for the isotropic and axial components of the Knight shift {cal K} as functions chi in the two materials. {cal K} presents a linear relation with chi only down to ~30 K. Below this temperature, the absolute value of the Knight-shift components grows more slowly than would be expected from extrapolating their high temperature behavior, suggesting temperature-dependent transferred-hyperfine fields at the Cu sites or a temperature-dependent lineshape asymmetry. We interpret these observations in terms of disorder of the density of conduction-electron states (DOS). A simple model of

  8. Transmission electron microscopy studies of mechanical alloying in the immiscible a-Fe2O3-SnO2 system

    DEFF Research Database (Denmark)

    Rickerby, D.G.; Jiang, Jianzhong; Lin, R.;

    1998-01-01

    Microstructural development and nanoscale compositional variations in mechanically alloyed Fe2O3-SnO2 powders have been examined by transmission electron microscopy and energy dispersive X-ray spectrometry. The mean grain size was found to stabilize around 10 nm after 19 h milling time, in close......, indicating that a supersaturated solid solution is formed, but that mixing may be locally inhomogeneous at the atomic level. Similar conclusions have been reported for studies of mechanical alloying in immiscible metallic systems. The tendency for SnO2 grains above a certain critical size to remain...

  9. Effect of amide type modified rapeseed oil as lubricating additive on friction and wear behavior of steel-steel and steel-aluminum alloy systems

    Institute of Scientific and Technical Information of China (English)

    FANG Jian-hua; CHEN Bo-shui; LIU Wei-min; DONG Lin; WANG Jiu

    2004-01-01

    A new type of environmentally friendly lube additive-amide type modified rapeseed oil was synthesized and characterized by infrared spectrum. Its effect on the friction and wear behavior of steel-steel and steel-aluminum alloy systems were investigated with a four-ball machine and an Optimol SRV friction and wear tester respectively.The morphographies of the worn surfaces were analyzed by means of scanning electron microscopy(SEM). The worn surfaces of the 2024Al alloy block were analyzed by means of X-ray photoelectron spectroscopy(XPS). The results show that the modified rapeseed oil as additives can obviously decrease the wear rate and friction coefficient of steel pair and steel-aluminum frictional pair. Its lubrication mechanism is inferred that a high strength complex protection films form on the worn surface of the Al alloy due to the adsorption or tribochemistry reaction of a long chain additive molecule and high reaction activity of N element.

  10. Anomalous decrease in X-ray diffraction intensities of Cu-Ni-Al-Co-Cr-Fe-Si alloy systems with multi-principal elements

    International Nuclear Information System (INIS)

    With an aim to understand the great reduction in the X-ray diffraction (XRD) intensities of high-entropy alloys, a series of Cu-Ni-Al-Co-Cr-Fe-Si alloys with systematic addition of principal elements from pure element to seven elements was investigated for quantitative analysis of XRD intensities. The variation of XRD peak intensities of the alloy system is similar to that caused by thermal effect, but the intensities further drop beyond the thermal effect with increasing number of incorporated principal elements. An intrinsic lattice distortion effect caused by the addition of multi-principal elements with different atomic sizes is expected for the anomalous decrease in XRD intensities. The mathematical factor of this distortion effect for the modification of XRD structure factor is formulated analogue to that of thermal effect

  11. Hardface coating systems and methods for metal alloys and other materials for wear and corrosion resistant applications

    Science.gov (United States)

    Seals, Roland D.

    2015-08-18

    The present disclosure relates generally to hardface coating systems and methods for metal alloys and other materials for wear and corrosion resistant applications. More specifically, the present disclosure relates to hardface coatings that include a network of titanium monoboride (TiB) needles or whiskers in a matrix, which are formed from titanium (Ti) and titanium diboride (TiB.sub.2) precursors by reactions enabled by the inherent energy provided by the process heat associated with coating deposition and, optionally, coating post-heat treatment. These hardface coatings are pyrophoric, thereby generating further reaction energy internally, and may be applied in a functionally graded manner. The hardface coatings may be deposited in the presence of a number of fluxing agents, beta stabilizers, densification aids, diffusional aids, and multimode particle size distributions to further enhance their performance characteristics.

  12. Anomalous glass transition behavior in Cu-Zr-Sn alloy system

    International Nuclear Information System (INIS)

    Research highlights: → Effects of Sn addition on anomalous glass transition behavior in Cu-Zr BMGs. → An unusual endothermic reaction in Cu55Zr40Sn5 ribbon. → Growth reaction of quenched-in nuclei from 0.4 nm to 3.7 nm in the supercooled liquid region. → This anomalous devitrification may be useful for the synthesis of a novel composite. - Abstract: We discuss the effect of Sn addition on anomalous glass transition behavior in Cu-Zr bulk-forming metallic glasses. We found that an unusual endothermic reaction in Cu55Zr40Sn5 ribbon can originate from the growth reaction of quenched-in nuclei from 0.4 nm to 3.7 nm in the supercooled liquid region. This anomalous devitrification may prove useful for the synthesis of a novel composite with uniform atomic/nanometer scale heterogeneity modulated by controlling cooling rate as well as by tailoring alloy composition.

  13. Interfacial Chemical Interactions in the (Alumina/Graphite/Al Alloys) System: Thermodynamic Modeling and Experimental Results

    Science.gov (United States)

    Gelbstein, M.; Edry, I.; Froumin, N.; Frage, N.

    2009-04-01

    The stability of alumina-coated graphite couples in liquid Al is investigated in the 1373 to 1573 K temperature range. A thermodynamic model was carried out to determine the mechanisms controlling the couple stability and the effect of alloying Al with high melting point element for instance U (up to 3 at. pct). It was established that the dissolved uranium dose not play any role in the interfacial interactions and that the couple stability is governed by the interactions with Al resulting in the release of gaseous products. The experiments focused on wetting kinetics under conditions allowing for an in-situ reduction of the alumina coating by the liquid Al. The experimental results confirm the predictions of the thermodynamic analysis.

  14. Slurry wear characteristics of zinc-based alloys: Effects of sand content of slurry, silicon addition to alloy system and traversal distance

    Institute of Scientific and Technical Information of China (English)

    B.K. PRASAD; O.P. MODI

    2009-01-01

    This investigation deals with the observations pertaining to the effects of specimen and slurry compositions as well as traversal distance on the slurry wear response of a zinc-based alloy. The composition of the alloy was altered by adding 4% silicon to it. The slurry composition was varied through changing the concentration of the sand particles in the range of 0-60% that were suspended in the (liquid) electrolyte. The electrolyte contained 4 g sodium chloride and 5 mL concentrated sulphuric acid dissolved in 10 L of water. The slurry wear tests were conducted at a speed of 7.02 m/s over the traversal distance range of 15-500 km. The wear rate increased initially with traversal distance, attained a maximum and decreased thereafter irrespective of the specimen and test environment. However, the wear rate peaks were less prominent in the liquid plus sand environments than the liquid-only medium. Further, the wear rate peak in the liquid-only medium appeared at a shorter traversal distance than the one in the sand containing slurries. Addition of sand particles to the electrolyte reduced the wear rate of the samples to 5%-15% depending on the sand concentration of the slurry. Moreover, intermediate (40%) sand content led to a maximum wear rate when compared with in the liquid plus sand media. However, this maximum was still less than in the liquid-only medium. The silicon containing alloy suffered from higher wear rates than the silicon free alloy samples when tested in the liquid-only medium. On the contrary, the trend reversed in liquid plus 20% and 40% sand environments whereas a mixed response was noted in the slurry containing 60% sand. In the latter case, the presence of silicon proved deleterious initially while an opposite trend was observed at longer traversal distances. The wear response of the samples was discussed in terms of specific features of their microconstituents like silicon and the predominant material removal mechanism in a given set of

  15. Alloying effect on the titanium alloys tendency to the salt corrosion

    International Nuclear Information System (INIS)

    Salt corrosion tendency of commercial titanium alloys, such as OT4, 0T4-1 (the Ti-Al-Mn system); VT14, VT16 (the Ti-Al-Mo-V system) and VT30 (the Ti-Mo-Sn-Zr system) is compared with the intensity of salt corrosion of VT1-0 titanium and experimental alloys of the Ti-Al and Ti-Mo systems. It is established that the salt corrosion tendency of alloys of the Ti-Al system increases when they are alloyed with manganese and decreases when they are alloyed with vanadium and molybdenum in combination. Alloys of the Ti-Mo system have no tendency to salt corrosion. Alloying with zirconium and tin brings about the propagation of salt corrosion in the alloys

  16. Through-thickness recrystallization characteristics of a laminated AA3xxx–AA6xxx aluminum alloy system

    Energy Technology Data Exchange (ETDEWEB)

    Liao, L.H., E-mail: l2liao@uwaterloo.ca [Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Ave. West, Waterloo, ON N2L 3G1 (Canada); Jin, H.; Gallerneault, M. [Formerly Novelis Research and Technology Centre, 945 Princess Street, Kingston, ON K7L 5L9 (Canada); Esmaeili, S., E-mail: shahrzad@uwaterloo.ca [Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Ave. West, Waterloo, ON N2L 3G1 (Canada)

    2015-03-15

    The through-thickness annealing behavior of a laminated AA3xxx–AA6xxx alloy system at 300 °C has been studied by scanning electron microscopy, electron backscatter diffraction analysis, electron probe micro-analysis, differential scanning calorimetry, and hardness measurement. Results show that the recrystallization process starts at the interface region between the AA3xxx (clad) and AA6xxx (core) layers. Subsequently, the recrystallization process front progresses into the core layer, while the clad layer is the last region to recrystallize. It is also found that precipitation precedes recrystallization in the entire laminate at the investigated temperature. The preferential onset of recrystallization at the interface region is attributed to the net driving pressure being the highest in this region. The factors that lead to such enhanced net driving pressure are (a) deformation incompatibility between the two alloy layers, (b) lower solute content of the interface, which also leads to lower volume fraction of precipitates, and (c) an accelerated rate of precipitate coarsening due to the presence of a higher density of dislocations. The gradual progress of recrystallization from the interface towards the core layer is dictated by precipitate coarsening and the dependence of its rate on the density of deformation-induced dislocations. The lower driving pressure due to lower work hardening capacity, high solute drag pressure due to Mn, and additional Zener drag from precipitates that form due to solute redistribution during annealing explain the late initiation of recrystallization in the clad layer. - Highlights: • The through-thickness recrystallization of a laminated system is investigated. • The early onset of recrystallization at the interface is discussed. • The effects of precipitation and coarsening on recrystallization are analyzed.

  17. Through-thickness recrystallization characteristics of a laminated AA3xxx–AA6xxx aluminum alloy system

    International Nuclear Information System (INIS)

    The through-thickness annealing behavior of a laminated AA3xxx–AA6xxx alloy system at 300 °C has been studied by scanning electron microscopy, electron backscatter diffraction analysis, electron probe micro-analysis, differential scanning calorimetry, and hardness measurement. Results show that the recrystallization process starts at the interface region between the AA3xxx (clad) and AA6xxx (core) layers. Subsequently, the recrystallization process front progresses into the core layer, while the clad layer is the last region to recrystallize. It is also found that precipitation precedes recrystallization in the entire laminate at the investigated temperature. The preferential onset of recrystallization at the interface region is attributed to the net driving pressure being the highest in this region. The factors that lead to such enhanced net driving pressure are (a) deformation incompatibility between the two alloy layers, (b) lower solute content of the interface, which also leads to lower volume fraction of precipitates, and (c) an accelerated rate of precipitate coarsening due to the presence of a higher density of dislocations. The gradual progress of recrystallization from the interface towards the core layer is dictated by precipitate coarsening and the dependence of its rate on the density of deformation-induced dislocations. The lower driving pressure due to lower work hardening capacity, high solute drag pressure due to Mn, and additional Zener drag from precipitates that form due to solute redistribution during annealing explain the late initiation of recrystallization in the clad layer. - Highlights: • The through-thickness recrystallization of a laminated system is investigated. • The early onset of recrystallization at the interface is discussed. • The effects of precipitation and coarsening on recrystallization are analyzed

  18. First-principles investigation of L10-disorder phase equilibria of Fe-Ni, -Pd, and -Pt binary alloy systems

    International Nuclear Information System (INIS)

    FLAPW total energy electronic structure calculations are combined with cluster variation method in order to perform first-principles investigation of phase equilibria for three kinds of Fe-based binary alloy systems, Fe-Ni, Fe-Pd, and Fe-Pt. A particular focus of the present investigation is placed on L10-disorder phase equilibria. The lattice vibration effects are incorporated within the quasi-harmonic approximation via Debye-Gruneisen model. The ground state analysis revealed that magnetism plays a crucial role in the phase stability of each system. The calculated transition temperatures for Fe-Pd and Fe-Pt systems are in close agreement with experimental ones. The lattice vibration effects further improves the accuracy, and it is found that magnetic fine structure also affects the resultant transition temperature in Fe-Pt system. Although L10-ordered phase does not appear as a stable ordered phase in a conventional phase diagram of Fe-Ni system, the present first-principles calculation suggests the possibility of the stabilization of this phase. The effect of the second nearest neighbor pair interactions as well as multibody interactions are investigated

  19. Development of a thermodynamic control system for the Fontan circulation pulsation device using shape memory alloy fibers.

    Science.gov (United States)

    Yamada, Akihiro; Shiraishi, Yasuyuki; Miura, Hidekazu; Hashem, Hashem Mohamed Omran; Tsuboko, Yusuke; Yamagishi, Masaaki; Yambe, Tomoyuki

    2015-09-01

    The Fontan procedure is one of the common surgical treatments for circulatory reconstruction in pediatric patients with congenital heart disease. In Fontan circulation, low pulsatility may induce localized lung ischemia and may impair the development of pulmonary peripheral endothelial cells. To promote pulmonary circulation in Fontan circulation, we have been developing a pediatric pulmonary circulatory pulsation device using shape memory alloy fibers attached from the outside of total cavopulmonary connection. In this study, we developed a new thermal control system for the device and examined its functions. We mounted on the device 16 fibers connected in parallel around an ePTFE graft circumferentially. To provide optimized contraction, we designed the new thermal control system. The system consisted of a thermistor, a pressure sensor, and a regulator that was controlled by the adaptive thermodynamic transfer functions. We monitored the parameters and calculated heat transfer function as well as pressure distribution on the graft surface. Then we examined and compared the dynamic contractile pressure and changes in surface temperature. As a result, by the application of the control based on the new feedback system analysis, the circumferential contractile pressure increased by 35%. The adaptive thermodynamic regulation was useful for the selection of alternative thresholds of the surface temperature of the graft. The system could achieve effective contraction for the pulsatile flow generation by the device. PMID:25894077

  20. Novel Concepts for Damage-Resistant Alloys in Next Generation Nuclear Power Systems - Final Report , Project 99-0280

    Energy Technology Data Exchange (ETDEWEB)

    Bruemmer, Stephen M.; Simonen, Edward P.; Gan, Jian; Garner, Francis A.; Gelles, David S.; Edwards, Danny J.; Andresen, Peter L.; Young, Lisa M.; Was, Gary S.; Fournier, L.; Sencer, Bulent H.

    2002-12-27

    The discovery of a damage-resistant alloy based on Hf solute additions to a low-carbon 316SS is the highlight of the Phase II research. This damage resistance is supported by characterization of radiation-induced microstructures and microchemistries along with measurements of environmental cracking. The addition of Hf to a low-carbon 316SS reduced the detrimental impact of radiation by changing the distribution of Hf. Pt additions reduced the impact of radiation on grain boundary segregation but did not alter its effect on microstructural damage development or cracking. Because cracking susceptibility is associated with several material characteristics, separate effect experiments exploring strength effects using non-irradiated stainless steels were conducted. These crack growth tests suggest that irradiation strength by itself can promote environmental cracking. The second concept for developing damage resistant alloys is the use of metastable precipitates to stabilize the microstructure during irradiation. Three alloys have been tailored for evaluation of precipitate stability influences on damage evolution. The first alloy is a Ni-base alloy (alloy 718) that has been characterized at low neutron irradiation doses but has not been characterized at high irradiation doses. The other two alloys are Fe-base alloys (PH 17-7 and PH 17-4) that have similar precipitate structures as alloy 718 but is more practical in nuclear structures because of the lower Ni content and hence lesser transmutation to He.

  1. Electron correlation and relativity of the 5f electrons in the U-Zr alloy system

    Science.gov (United States)

    Söderlind, P.; Sadigh, B.; Lordi, V.; Landa, A.; Turchi, P. E. A.

    2014-01-01

    We address a recently communicated conception that spin-orbit interaction and strong electron correlations are important for the metal fuel U-Zr system. Here, we show that (i) relativistic effects only marginally correct the uranium metal equation-of-state and (ii) addition of onsite Coulomb repulsion leads to an unphysical magnetic ground state of the body-centered cubic (γ) phase and a grossly overestimated equilibrium volume. Consequently, LSDA + U is deemed unsuitable for describing the electronic structure of the U-Zr system. Recently, Xiong et al. [1] reported on thermodynamic modeling of the U-Zr system motivated by its potential as a nuclear fuel for fast breeder reactors. This work [1] came on the heels of another report by Landa et al. [2] on the same system, but with very different results for the formation enthalpies and ultimate conclusion on the U-Zr phase diagram. The authors [1] argue that their calculated energetics are significantly more accurate than that by Landa et al. [2], and they further attribute the difference to strong electron correlations and the relativistic spin-orbit interaction.In the present letter we show that uranium metal, and thus the U-Zr metal nuclear fuel system, possess weakly correlated electrons that are adequately described within density-functional theory in the generalized gradient approximation, and that addition of onsite Coulomb repulsion using the LSDA + U formalism leads to finite magnetization of the γ phase in contradiction to experiments. Furthermore, we show that spin-orbit interaction is quite weak in uranium metal and that its inclusion will not significantly change the chemical bonding and formation enthalpies.In order to illustrate our arguments, we perform comparative electronic-structure calculations using the full-potential linear augmented plane-wave (FPLAPW) method and the projector augmented plane-wave (PAW) method as implemented in the Wien2K [3] and VASP [4] codes. The Wien2K computations are set

  2. Investigating of the Effect of Rectangular and Trapezium Cross Section of Gating System by CFD Simulation in Cooling of Aluminium Alloy in a Permanent Mould Casting

    Directory of Open Access Journals (Sweden)

    N. A. Chowdhury

    2012-01-01

    Full Text Available This paper presents a systemic study of the effect of different cross section of gate in permanent mould casting of aluminium alloy. To ensure best quality of the product the mould cavity must be filled with clean metal in a controlled manner to ensure smooth, uniform and complete filling. A gating system controls smooth, uniform and complete filling of the cavity by the molten metal. In this paper, CFD models illustrating the effect of rectangular and trapezium cross sections of gating on cooling of Aluminium alloy in a permanent mould casting were investigated. Same hydraulic diameter was assigned for each of the cross section of gating systems. Bottom gating system is used for its low gas entrapment and less surface defect characteristics. By analyzing it has been observed that in rectangular cross section the cooling is more rapid than trapezium cross sections considered in the investigation.

  3. Systems based on hypo-eutectic Mg–Mg{sub 2}Ni alloys for medium to large scale hydrogen storage and delivery

    Energy Technology Data Exchange (ETDEWEB)

    Moroz, Stephanie, E-mail: stephanie.moroz@hydrexia.com; Tan, Xin Fu; Pierce, Jordan; Greaves, Matthew; Duguid, Andrew; Dumur, Krista; Ng, Jeffrey

    2013-12-15

    Highlights: •High performance, low cost hydrogen storage systems are in development based on a Mg–Mg2Ni alloy. •These systems have higher storage density than compressed gas •They can be filled with hydrogen at low pressure, removing the need for a compressor •The systems can deliver hydrogen at a lower cost per unit of hydrogen delivered than compressed gas. •The metal hydride systems also have significant safety advantages over compressed gas. -- Abstract: Magnesium based metal hydrides have a number of attractive properties for hydrogen storage, particularly the high storage density and the safety benefits of low pressure operation. A hypo-eutectic Mg–Mg{sub 2}Ni alloy has been developed. The material can be produced at a much lower cost than ball-milled materials while achieving a reversible storage of 6.5–7 wt% hydrogen at a rate of reaction that is acceptable for existing industrial applications. This alloy has been employed in a series of increasingly large prototype systems, reaching commercial scale in 2010 with a system storing 22 kg of hydrogen, appropriate for industrial merchant applications. The technology is also under development for larger scale applications such as refueling infrastructure and energy storage. This paper will discuss the potential applications of these systems and their technical and economic comparison to traditional compressed gas hydrogen storage and delivery.

  4. Regularities of structure formation and magnetic properties production in Fe-Cr-Co system magnetically hard alloys

    International Nuclear Information System (INIS)

    A new approach to alloy development is suggested. The approach is based on the thermodynamic model and the knowledge of structure formation regularities determining magnetic properties. The method suggested was used in development of new magnetically hard Fe-Cr-Co (V, Mo) alloys and allowed to substitute computer analysis for the most part of expensive experiments

  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. An Introduction to a Porous Shape Memory Alloy Dynamic Data Driven Application System

    KAUST Repository

    Douglas, Craig C.

    2012-06-02

    Shape Memory Alloys are capable of changing their crystallographic structure due to changes of temperature and/or stress. Our research focuses on three points: (1) Iterative Homogenization of Porous SMAs: Development of a Multiscale Model of porous SMAs utilizing iterative homogenization and based on existing knowledge of constitutive modeling of polycrystalline SMAs. (2) DDDAS: Develop tools to turn on and off the sensors and heating unit(s), to monitor on-line data streams, to change scales based on incoming data, and to control what type of data is generated. The application must have the capability to be run and steered remotely. (3) Modeling and applications of porous SMA: Vibration isolation devices with SMA and porous SMA components for aerospace applications will be analyzed and tested. Numerical tools for modeling porous SMAs with a second viscous phase will be developed.The outcome will be a robust, three-dimensional, multiscale model of porous SMA that can be used in complicated, real-life structural analysis of SMA components using a DDDAS framework.

  7. Bio-inspired Actuating System for Swimming Using Shape Memory Alloy Composites

    Institute of Scientific and Technical Information of China (English)

    Tao Tao; Yuan-Chang Liang; Minoru Taya

    2006-01-01

    The paper addresses the designs of a caudal peduncle actuator, which is able to furnish a thrust for swimming of a robotic fish. The caudal peduncle actuator is based on concepts of ferromagnetic shape memory alloy (FSMA) composite and hybrid mechanism that can provide a fast response and a strong thrust. The caudal peduncle actuator was inspired by Scomber Scombrus which utilises thunniform mode swimming, which is the most efficient locomotion mode evolved in the aquatic environment, where the thrust is generated by the lift-based method, allowing high cruising speeds to be maintained for a long period of time. The morphology of an average size Scomber Scombrus (length in 310 mm) was investigated, and a 1:1 scale caudal peduncle actuator prototype was modelled and fabricated. The propulsive wave characteristics of the fish at steady speeds were employed as initial design objectives. Some key design parameters are investigated, i.e. aspect ratio (AR) (AR = 3.49), Reynolds number (Re = 429 649), reduced frequency (σ = 1.03), Strouhal number (St = 0.306) and the maximum strain of the bent tail was estimated at ε = 1.11% which is in the range of superelasticity. The experimental test of the actuator was carried out in a water tank. By applying 7 V and 2.5 A, the actuator can reach the tip-to-tip rotational angle of 85° at 4 Hz.

  8. Facile synthesis, pharmacokinetic and systemic clearance evaluation, and positron emission tomography cancer imaging of 64Cu-Au alloy nanoclusters

    Science.gov (United States)

    Zhao, Yongfeng; Sultan, Deborah; Detering, Lisa; Luehmann, Hannah; Liu, Yongjian

    2014-10-01

    Gold nanoparticles have been widely used for oncological applications including diagnosis and therapy. However, the non-specific mononuclear phagocyte system accumulation and potential long-term toxicity have significantly limited clinical translation. One strategy to overcome these shortcomings is to reduce the size of gold nanoparticles to allow renal clearance. Herein, we report the preparation of 64Cu alloyed gold nanoclusters (64CuAuNCs) for in vivo evaluation of pharmacokinetics, systemic clearance, and positron emission tomography (PET) imaging in a mouse prostate cancer model. The facile synthesis in acqueous solution allowed precisely controlled 64Cu incorporation for high radiolabeling specific activity and stability for sensitive and accurate detection. Through surface pegylation with 350 Da polyethylene glycol (PEG), the 64CuAuNCs-PEG350 afforded optimal biodistribution and significant renal and hepatobiliary excretion. PET imaging showed low non-specific tumor uptake, indicating its potential for active targeting of clinically relevant biomarkers in tumor and metastatic organs.Gold nanoparticles have been widely used for oncological applications including diagnosis and therapy. However, the non-specific mononuclear phagocyte system accumulation and potential long-term toxicity have significantly limited clinical translation. One strategy to overcome these shortcomings is to reduce the size of gold nanoparticles to allow renal clearance. Herein, we report the preparation of 64Cu alloyed gold nanoclusters (64CuAuNCs) for in vivo evaluation of pharmacokinetics, systemic clearance, and positron emission tomography (PET) imaging in a mouse prostate cancer model. The facile synthesis in acqueous solution allowed precisely controlled 64Cu incorporation for high radiolabeling specific activity and stability for sensitive and accurate detection. Through surface pegylation with 350 Da polyethylene glycol (PEG), the 64CuAuNCs-PEG350 afforded optimal

  9. Development of generator-cooling hydrogen purity improvement system using hydrogen absorbing alloy; Suiso kyuzo gokin ni yoru hatsudenkinai suiso jundo kojo system no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Y.; Sato, J.; Haruki, N.; Kogi, T.; Okuno, Y. [The Kansai Electric Power Co. Inc., Osaka (Japan); Takeda, H.; Wakisaka, Y. [The Japan Steel Works, Ltd., Tokyo (Japan); Fujita, T. [Mitsubishi Electric Corp., Tokyo (Japan)

    1997-01-31

    A generator-cooling hydrogen purity improvement system was developed by utilizing hydrogen absorbing and discharging functions of hydrogen storage alloy. For demonstration test with an actual machine, four elements, Ca, Ni, Mm and Al, were used as hydrogen storage alloys. To treat hydrogen gas with a wide range of purity and reduce hydrogen gas feed, flow operation for hydrogen purity improvement, batch operation, and recycle operation for maintaining the hydrogen purity were performed. As a result of the generator-cooling hydrogen purity improvement demonstration test, it was found that the hydrogen purity can be enhanced from 97.69% before operation to 99.9% after operation for 104 hours and to 99.95% after operation for 140 hours. The hydrogen recovery rates during flow test and batch test were between 92 and 95%. For the hydrogen purity maintaining test, it was confirmed that the high hydrogen purity of 99.9% has been continuously maintained for 140 days, and that the hydrogen recovery rate was over 99%. 2 refs., 15 figs., 3 tabs.

  10. The constitution of alloys in the Al-rich corner of the Al-Si-Sm ternary system

    International Nuclear Information System (INIS)

    The constitution of alloys and the liquidus surface in the Al-rich corner of the Al-Si-Sm ternary system were determined by the examination of controlled heated and cooled specimens, as well as heat-treated specimens by means of optical and scanning electron microscopy, energy-dispersive X-ray spectroscopy, differential thermal analysis and X-ray diffraction. The Al-rich corner of the Al-Si-Sm ternary system comprises five regions of primary crystallisation (αAl, βSi, Al3Sm, Al2Si2Sm and AlSiSm) with following characteristic invariant reaction sequences: ternary eutectic reaction L → αAl + βSi + Al2Si2Sm, and two liquidus transition reactions, i. e., L + Al3Sm → αAl + AlSiSm, and L + AlSiSm → αAl + Al2Si2Sm. Along with the position of ternary eutectic and both interstitial points in the Al-rich corner of the Al-Si-Sm ternary system, the temperatures for each reaction were determined. (orig.)

  11. Critical behavior and magnetocaloric effect in Co50−xNixCr25Al25 (x = 0 and 5) full Heusler alloy system

    International Nuclear Information System (INIS)

    Highlights: • The Curie temperature of alloy series of Co50−xNixCr25Al25 decreases with increasing x. • The critical exponents behavior and scaling relation of the alloy series have been investigated. • Using M–H data, employing Modified Arrott plot and Kouvel–Fisher plot exponents are estimated. • The estimated critical exponent values match very well with the mean field theory. • Under a magnetic field maximum up to 5 T, normal magnetocaloric effect has been observed. - Abstract: This work reports the investigation of critical behavior of Co50−xNixCr25Al25 (x = 0 and 5) and magneto caloric effect (MCE) of bulk Co2CrAl full Heusler alloy system. The alloy series of Co50−xNixCr25Al25 (x = 0, 1, 2, 3, 4 and 5) have been prepared using arc melting technique. The magnetic properties of all the samples have been studied in the temperature range of 5–300 K. The value of Curie temperature (TC) is found to decrease with increasing doping concentration of the Ni (substitution of Ni at Co site). The critical exponents behavior and scaling relation have been investigated using magnetic isotherms in Co50−xNixCr25Al25 (x = 0 and 5) alloys. The critical exponents are estimated by various techniques such as, Modified Arrott plot, Kouvel–Fisher plot and critical isotherm technique. The value of critical exponents vicinity to the second order magnetic phase transition of Co50Cr25Al25 were found to be β = 0.488 (7), γ = 1.144 (16) and δ = 3.336 (5) with TC = 328.64 (5) K whereas for Co50Ni5Cr25Al25 the values are β = 0.522 (13), γ = 1.014 (6) and δ = 3.043 (7) with TC = 285.71 (11). The critical exponent values for both the samples are almost similar to the value as predicted by mean field theory. This has been best explained by long range mean field like ferromagnetic interaction in the entire Co50−xNixCr25Al25 (x = 0, 5) highly spin polarized full Heusler alloy system. Under an external magnetic field maximum up to 5 T, normal magneto caloric

  12. Electrical Resistance Alloys and Low-Expansion Alloys

    DEFF Research Database (Denmark)

    Kjer, Torben

    1996-01-01

    The article gives an overview of electrical resistance alloys and alloys with low thermal expansion. The electrical resistance alloys comprise resistance alloys, heating alloys and thermostat alloys. The low expansion alloys comprise alloys with very low expansion coefficients, alloys with very low...... thermoelastic coefficients and age hardenable low expansion alloys....

  13. Glass formation in eutectic alloys

    International Nuclear Information System (INIS)

    We have analyzed the glass forming ability around eutectic composition in terms of the competitive growth/formation of primary dendrites, eutectic and glass. It is concluded that the glass forming ability of a eutectic alloy system depends on the type of the eutectics, i.e. symmetric or asymmetric eutectic coupled zone. For the alloy systems with symmetric eutectic coupled zone, the best glass forming alloys should be at or very close to the eutectic composition. For the alloys with asymmetric eutectic coupled zone, which is associated with the irregular eutectic, the best glass forming alloys should be at off-eutectic compositions, probably towards the side of the faceted phase with a high entropy in the phase diagram. (orig.)

  14. Contribution to the knowledge of the Cu–Sn–Zn system for compositions close to brass alloys

    OpenAIRE

    Vilarinho, Cândida; Soares, Delfim; Castro, F.

    2004-01-01

    The effect of tin content in the equilibrium phases of the Cu–Zn-based alloys, within the range of chemical compositions with interest to brass producers is described. For this purpose, ternary alloys with copper contents between 55.4 and 67.5 wt.% and tin contents up to 5.30 wt.% have been studied. The chemical composition of each alloy has been determined by X-ray fluorescence spectrometry (XRF). Isothermal homogenization, followed by rapid cooling, has been employed to determine the ...

  15. A Review of FSW Research on Dissimilar Metal and Alloy Systems

    Science.gov (United States)

    Murr, L. E.

    2010-11-01

    This review summarizes friction-stir welding (FSW) research over a period of a decade and a half, involving 18 different same materials FSW reference systems, and the FSW of 25 different, dissimilar materials systems. These are summarized in tables. The FSW of dissimilar materials systems is distinguished from same materials systems FSW by the formation of complex, intercalated vortex, and related flow patterns. These intercalated, lamellar-like patterns represent solid-state flow by dynamic recrystallization (DRX) which facilitates unrecrystallized, block flow in the DRX regime. A detailed characterization of representative systems involving optical and transmission electron microscopy is also presented. Residual microindentation hardness or other hardness measured across the weld face provides comparative performance signatures for the same material FSW systems in contrast to the dissimilar FSW systems. Hardness fluctuations or complex spikes occurring in the dissimilar systems are skewed from the weld centerline and are shifted when the tool rotation direction changes or the advancing side is reversed.

  16. Preparation of ultra fine-grained metal hydride alloy of Mg-Fe system by mechanical milling for hydrogen storage application

    International Nuclear Information System (INIS)

    The synthesis and characterization of ultra fine-grained metal hydride alloy of the Mg–Fe system by mechanical milling technique have been performed. The Mg and Fe powders were mixed and milled with the variation of milling time 0, 10, 20, 30, 40, 50, 60 and 70 hours. The refinement of the X-ray diffractions reveals that the sample consists of three phases, namely nanocrystalline Mg, Fe, and FeH with the average grain size of approximately less than 5 nm. The observations of the microstructure using SEM shows that the sample consists of very small particles with sizes of about 100 – 500 nm. It is concluded that the ultra fine-grained metal hydride alloy of the Mg-Fe system for hydrogen storage application can be prepared by mechanical milling technique. (author)

  17. Diffusion kinetics originating a bifurcation of the final states in the phase separation of the Ni3Al1-xVx alloy system

    International Nuclear Information System (INIS)

    The evolution of states related to D022 precipitation in the supersaturated L12 matrix to form the L12+D022 equilibrium state of the Ni3Al1-xVx (0.40≤x≤0.60) alloy system was examined by transmission electron microscopy. Our results revealed that the microstructure of the initial L12 single state varied with the change in the alloy composition and that such a variation caused a bifurcation of the final states, i.e., the L12+D022 equilibrium state (x = 0.40 and x≥0.55) and the metastable L12 single state (0.402 matrix from supersaturated to equilibrium ones during the isothermal process. The final bifurcation due to such sensitivity strongly suggests that the diffusion kinetics should be treated as an 'open system' in terms of the annihilation of vacancies under the present thermodynamic conditions

  18. The relationship between chromium content and erosion-corrosion resistance of Fe-Cr{sub C} alloy system

    Energy Technology Data Exchange (ETDEWEB)

    Hue, Nguyen Viet; Phuong, Doan Dinh; Tich, Nguyen Van; Binh, Hoang Thi [The Institute of Materials Science Hoang Quoc Viet Rd., Hanoi (Viet Nam)

    2002-02-15

    In order to determine the influence of chromium on erosion-corrosion coefficient of alloy in acid media, experiments were performed with chromium content in the range of 12-33% in different typical erosion -corrosion environments such as solution of sand with free acid in pH 2-7. The erosion-corrosion coefficient was evaluated by Apparatus for abrasion-corrosion testing. Wear coefficient, K, was calculated by formula: K= {Delta} M{sub etalon} / {Delta} M{sub alloy} Testing results were showed that the alloy with composition (%): Cr = 28-30: C = 1.8-2.0: Mn = 2.5-3.0: is the optimum for manufacturing details resistant erosion-corrosion in media upto pH=2-3. This alloy is used successfully to produce details for sand-pumps, minerals processing cyclones

  19. Thermodynamics and separation factor of uranium from lanthanum in liquid eutectic gallium-indium alloy/molten salt system

    International Nuclear Information System (INIS)

    Highlights: • The behavior of lanthanum and uranium on liquid gallium-indium eutectic alloy was carried out. The experiments were done in fused 3LiCl-2KCl eutectic vs. Cl−/Cl2 reference electrode at the temperature range 723–823 K. Thermodynamic properties of La-Ga-In and U-Ga-In alloys and the separation factor U/La were calculated. - Abstract: This work presents the electrochemical study of lanthanum and uranium compounds in fused 3LiCl-2KCl eutectic vs. Cl−/Cl2 reference electrode in the temperature range 723–823 K on liquid gallium-indium eutectic alloy. Thermodynamics and the activity coefficients of lanthanum and uranium were studied. The separation factor of uranium from lanthanum on gallium-indium eutectic alloy was determined

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

    OpenAIRE

    Wang Xinzhi; He Yurong; Zheng Yan; Ma Junjun; H. Inaki Schlaberg

    2014-01-01

    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 stres...

  1. Magnetic, electrical, thermal transport, and thermoelectric proberties of the ... and ... complex metallic alloy phases in the Al-Pd-Mn system

    OpenAIRE

    Dolinsek, J.; Jeglic, P.; Urban, K; McGuiness, P. J.; Jaglicic, Z.; Bilusic, A.; Bihar, Z.; Smontara, A.; Landauro, C.V.; Feuerbacher, M.; Grushko, B.

    2005-01-01

    The Al-Pd-Mn system of intermetallics contains complex metallic alloy (CMA) phases, whose crystal structures are based on giant unit cells comprising up to more than a thousand atoms per cell. We performed investigation of the magnetic, electrical, and thermal transport and thermoelectric properties of the xi(') phase and the related Psi phase on single-crystalline samples grown by the Bridgman technique. The samples are diamagnets with a tiny paramagnetic Curie-like magnetization and an esti...

  2. Mo-Si alloy development

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.T.; Heatherly, L.; Wright, J.L. [Oak Ridge National Lab., TN (United States)

    1996-06-01

    The objective of this task is to develop new-generation corrosion-resistant Mo-Si intermetallic alloys as hot components in advanced fossil energy conversion and combustion systems. The initial effort is devoted to Mo{sub 5}-Si{sub 3}-base (MSB) alloys containing boron additions. Three MSB alloys based on Mo-10.5Si-1.1B (wt %), weighing 1500 g were prepared by hot pressing of elemental and alloy powders at temperatures to 1600{degrees}C in vacuum. Microporosities and glassy-phase (probably silicate phases) formations are identified as the major concerns for preparation of MSB alloys by powder metallurgy. Suggestions are made to alleviate the problems of material processing.

  3. A Combinatorial Approach to the Investigation of Metal Systems that Form Both Bulk Metallic Glasses and High Entropy Alloys

    Science.gov (United States)

    Welk, Brian A.; Gibson, Mark A.; Fraser, Hamish L.

    2016-03-01

    In this work, compositionally graded specimens were deposited using the laser engineered net-shaping (LENS™) additive manufacturing technique to study the glass-forming ability of two bulk metallic glass (BMG) and high entropy alloy (HEA) composite systems. The first graded specimen varied from Zr57Ti5Al10Cu20Ni8 (BMG) to CoCrFeNiCu0.5 (HEA) and the second graded specimen varied from TiZrCuNb (BMG) to (TiZrCuNb)65Ni35 (HEA). After deposition, laser surface melting experiments were performed parallel to the gradient to remelt and rapidly solidify the specimen. Scanning electron microscopy and energy dispersive x-ray spectroscopy were used to determine the morphology and composition variations in the as-deposited and laser surface melted phases. Selected area diffraction of the melt pool regions confirmed an almost fully amorphous region in the first gradient and an amorphous matrix/crystalline dendrite composite structure in the second gradient.

  4. System-Level Design of a Shape Memory Alloy Actuator for Active Clearance Control in the High-Pressure Turbine

    Science.gov (United States)

    DeCastro, Jonathan A.; Melcher, Kevin J.; Noebe, Ronald D.

    2005-01-01

    This paper describes results of a numerical analysis evaluating the feasibility of high-temperature shape memory alloys (HTSMA) for active clearance control actuation in the high-pressure turbine section of a modern turbofan engine. The prototype actuator concept considered here consists of parallel HTSMA wires attached to the shroud that is located on the exterior of the turbine case. A transient model of an HTSMA actuator was used to evaluate active clearance control at various operating points in a test bed aircraft engine simulation. For the engine under consideration, each actuator must be designed to counteract loads from 380 to 2000 lbf and displace at least 0.033 inches. Design results show that an actuator comprised of 10 wires 2 inches in length is adequate for control at critical engine operating points and still exhibits acceptable failsafe operability and cycle life. A proportional-integral-derivative (PID) controller with integrator windup protection was implemented to control clearance amidst engine transients during a normal mission. Simulation results show that the control system exhibits minimal variability in clearance control performance across the operating envelope. The final actuator design is sufficiently small to fit within the limited space outside the high-pressure turbine case and is shown to consume only small amounts of bleed air to adequately regulate temperature.

  5. First-principles calculation of phase equilibria and phase separation of the Fe-Ni alloy system

    Institute of Scientific and Technical Information of China (English)

    Ying Chen; Shuichi Iwata; Tetsuo Mohri

    2006-01-01

    Theoretical investigation of the phase equilibria of the Fe-Ni alloy has been performed by combining the FLAPW total energy calculations and the Cluster Variation Method through the Cluster Expansion Method. The calculations have proved the stabilization of the L12 phase at 1:3 stoichiometry, which is in agreement with the experimental result,and predicted the existence of L10 as a stable phase below 550 K; this L10 phase has been missing in the conventional phasediagram. The calculations are extended to the Fe-rich region that is characterized by a wide range phase separation and has drawn considerable attention because of the intriguing Invar property associated with a Fe concentration of 65%. To reveal the origin of the phase separation, a P-V curve in an entire concentration range is derived by the second derivative of free energy functional of the disordered phase with respect to the volume. The calculation confirmed that the phase separation is caused by the breakdown of the mechanical-stability criterion. The newly calculated phase separation line combined with the L10 and L12 order-disordered phase boundaries provides phase equilibria in the wider concentration range of the system. Furthermore, a coefficient of thermal expansion (CTE) is attempted by incorporating the thermal vibration effect through harmonic approximation of the Debye-Gruneisen model. The Invar behavior has been reproduced, and the origin of this anomalous volume change has been discussed.

  6. Dual chamber shape memory alloy unplugging and mixing system coupled to a high pressure optical cell for biophysical studies

    International Nuclear Information System (INIS)

    High pressure optical measurements are useful for understanding structure and function of biological molecules. Commonly used high-pressure optical cells can only observe a single sample under elevated pressure. If researchers wish to observe the interaction between different biological samples, they must mix the samples at atmospheric pressure, place the mixture within the pressure chamber, and wait until the desired pressure is reached. In many cases, researchers want to observe the initial reaction between two separate biological samples; however, the sample mixing and the assembly of the high pressure optical cell coupled with a spectrometer at desired pressures can take several minutes or longer. Our current design uses a shape memory alloy (SMA) spring actuator to seal a dual chamber cuvette for separation of two different biological samples. Once the desired pressure is reached, power is applied to the system that activates the SMA to unplug and mix the two samples using a micro dc-motor. During the mixing efficiency tests, deionized water was placed in the top chamber of the cuvette and an aqueous solution of carboxyfluorescein (a fluorescent dye) placed in the bottom chamber. Based on this design, we were able to achieve a total unplugging and mixing time within a few seconds (at atmospheric pressure). Quicker mixing means researchers will have more reliable data for analyzing the initial reactions between two different biological samples. Future tests on this new actuator will be conducted at elevated pressures. (paper)

  7. Mechanical alloying in Fe2O3-MO (M: Zn, Ni, Cu, Mg) systems

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Gerward, Leif; Mørup, Steen

    1999-01-01

    MFe2O4 ferrites are critically discussed. No significant with respect to ferrite formation rates was observed in open and closed containers used here. In the Fe2O3/ZnO system, a single ferrite phase can be synthesized but in other systems no significant amounts of ferrites are formed by high...

  8. Super ODS steels R and D for fuel cladding of next generation nuclear systems. 1) Introduction and alloy design

    International Nuclear Information System (INIS)

    Cladding material development is essential for realization of highly efficient high burn-up operation of next generation nuclear systems, where high performance is required for the materials, that is, high strength at elevated temperature, high resistance to corrosion and high resistance to irradiation. Oxide dispersion strengthening (ODS) ferritic steels are considered to be most adequate for the cladding material because of their high strength at elevated temperature. In this work, 'Super ODS steel' that has better corrosion resistance than 9Cr-ODS steel, has been developed for application to cladding of a variety of next generation nuclear systems. In the following ten papers, the recent experimental results of 'Super ODS steel' R and D will be presented, indicating that many unexpected preferable features were found in the mechanical properties of nano-sized oxide dispersion high-Cr ODS ferritic steel. A series of paper begins with alloy design of 'Super ODS steel'. Corrosion issue requires Cr concentration more than 14wt.%, but aging embrittlement issue requires less than 16wt.%. An addition of 4wt.%Al is effective to improve corrosion resistance of 16wt.%Cr-ODS steel in supercritical water (SCW) and lead-bismuth eutectic (LBE), while it is detrimental to high-temperature strength. Additions of 2wt.%W and 0.1wt.%Ti are necessary to keep high strength at elevated temperatures. An addition of small amount of Zr or Hf results in a significant increase in creep strength at 700degC in Al added ODS steels. Tube manufacturing was successfully done for the super ODS steel candidates. 'Super ODS steel' is promising for the fuel cladding material of next generation nuclear systems, and the R and D is now ready to proceed to the next stage of empirical verification. (author)

  9. Theory of Random Anisotropic Magnetic Alloys

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker

    1976-01-01

    A mean-field-crystal-field theory is developed for random, multicomponent, anisotropic magnetic alloys. It is specially applicable to rare-earth alloys. A discussion is given of multicritical points and phase transitions between various states characterized by order parameters with different....... Quantitative agreement can be obtained by increasing the interaction between different alloy elements, in particular for alloys with very different axial anisotropy, e.g., Tb-Tm. A model system consisting of a singlet-singlet and singlet-doublet alloy is discussed in detail. A simple procedure to include...

  10. Ferromagnetic bulk glassy alloys

    International Nuclear Information System (INIS)

    This paper deals with the review on the formation, thermal stability and magnetic properties of the Fe-based bulk glassy alloys in as-cast bulk and melt-spun ribbon forms. A large supercooled liquid region over 50 K before crystallization was obtained in Fe-(Al, Ga)-(P, C, B, Si), Fe-(Cr, Mo, Nb)-(Al, Ga)-(P, C, B) and (Fe, Co, Ni)-Zr-M-B (M=Ti, Hf, V, Nb, Ta, Cr, Mo and W) systems and bulk glassy alloys were produced in a thickness range below 2 mm for the Fe-(Al, Ga)-(P, C, B, Si) system and 6 mm for the Fe-Co-(Zr, Nb, Ta)-(Mo, W)-B system by copper-mold casting. The ring-shaped glassy Fe-(Al, Ga)-(P, C, B, Si) alloys exhibit much better soft magnetic properties as compared with the ring-shaped alloy made from the melt-spun ribbon because of the formation of the unique domain structure. The good combination of high glass-forming ability and good soft magnetic properties indicates the possibility of future development as a new bulk glassy magnetic material

  11. Evaluating protection systems against marine corrosion of aeronautic alloy Alclad 2024-T3

    Directory of Open Access Journals (Sweden)

    William Aperador Chaparro

    2011-05-01

    Full Text Available  This paper shows how two coating systems were obtained as an alternative for protection against corrosion of al clad 2024-T3which is used in battery compartment manufacture for T-41 aircraft. Such systems consist of three types of organic resin: a first layer of P-115 polyester resin as the first coating on both systems, and a second layer of Hetron 197-3 polyester resin in the first system and vinyl-ester resin in the second one. Scanning electron microscopy (SEM was used for surface morphology analysis, showing the roughness produced by surface treatment. The coatings were electrochemically characterised by electro chemical impedance spectroscopy (EIS and Tafel polarization curves; it was found that both systems had good performance against corrosion in a marine environment and the chemical surface preparation system had a superior protective pattern for Alodine5700 + 197-3 Hetron, a 1.42x10-12mpycorrosion rate being obtained while substratum rate was 1.59x10-7 mpy. 

  12. Features of formation of nanocrystalline state in internal- oxidized V-Cr-Zr-W and V-Mo-Zr system alloys during deformation by torsion under pressure

    Science.gov (United States)

    Smirnov, I. V.; Ditenberg, I. A.; Grinayev, K. V.; Radishevsky, V. L.

    2016-02-01

    The results of investigation of features of nanostructural state formed during deformation by torsion under pressure in high-strength vanadium V-Cr-Zr-W and V-Mo-Zr systems alloys are presented. It was found that after deformation at number of revolutions N = 1, samples are characterized by high anisotropy of defect and grain structure. Inside grains, limited by high-angle boundaries, the formation of two-level structure states was revealed: fragmentation of the above grains on nanofragments from 5 to 20 nm in size with a dipole nature of low-angle misorientations and high (hundreds of degrees per micron) elastic curvature of crystal lattice. Formation of the above structural states leads to a 3-fold increase in microhardness values. Further increase in deformation degree leads to fracture of samples of vanadium alloy V-Mo-Zr with a high volumetric content of fine-disperse oxide phase. At the same time V-Cr-Zr-W-system alloy with a lower concentration of Zr and, as a result, a lower volume fraction of fine particles remains ductile.

  13. Effect of the substitutional elements on the microstructure of the Ti-15Mo-Zr and Ti-15Zr-Mo systems alloys

    Directory of Open Access Journals (Sweden)

    Diego Rafael Nespeque Correa

    2015-04-01

    Full Text Available Titanium alloys have excellent biocompatibility, and combined with their low elastic modulus, become more efficient when applied in orthopedic prostheses. Samples of Ti-15Mo-Zr and Ti-15Zr-Mo system alloys were prepared using an arc-melting furnace with argon atmosphere. The chemical quantitative analysis was performed using an optical emission spectrometer with inductively coupled plasma and thermal conductivity difference. The X-ray diffractograms, allied with optical microscopy, revealed the structure and microstructure of the samples. The mechanical analysis was evaluated by Vickers microhardness measurements. The structure and microstructure of alloys were sensitive to molybdenum and zirconium concentration, presenting α′, α″ and β phases. Molybdenum proved to have greater β-stabilizer action than zirconium. Microhardness was changed with addition of molybdenum and zirconium, having Ti-15Zr-10Mo (436 ± 2 HV and Ti-15Mo-10Zr (378 ± 4 HV the highest values in each system.

  14. 铝合金游艇液压系统的设计%Design of the Hydraulic Control System of Aluminum Alloy Yacht

    Institute of Scientific and Technical Information of China (English)

    凌勇坚; 李安定; 张良华; 姜宝东; 方文炜

    2013-01-01

    This paper describes the design of a new aluminium alloy yacht used water sightseeing and sailing in the waters of Taihu. It focuses on introducing the design principle and characteristic of the hydraulic control system of the aluminum boat propeller and the winch, and the alloy yacht’s the actual use conditions and social value.%  叙述了一种用于水上观光游览、航行于太湖水域的新款式铝合金游艇的设计,重点介绍了该铝艇螺旋桨液压控制系统、绞盘机液压控制系统两大部分的设计原理和特点,以及完工后的该艇实际使用情况和社会价值。

  15. Liquid structure as a guide for phase stability in the solid state: Discovery of a stable compound in the Au-Si alloy system

    International Nuclear Information System (INIS)

    A new crystalline ground state was discovered in the Au-Si system through first-principles electronic structure calculations. The new structure was found using the experimentally and theoretically determined local atomic structure in the liquid as a guide for the solid state. Local atomic structure in the liquid was matched with that for all known crystal structures as compiled in the Pauling File structural database. The best matching crystalline structures were then explicitly calculated using first-principles methods. Most candidate crystal structures were found to be close, but above the enthalpy of a composition weighted average of the face-centered cubic Au and diamond structure Si terminal phases, but one crystal structure was more stable than the terminal phases by about 10 meV atom-1 at T = 0 K. As first-principles simulations of local structure are feasible for most liquid alloys, the present methodology is applicable to other alloys lying near a eutectic composition.

  16. Auger electron spectroscopy of alloys

    International Nuclear Information System (INIS)

    This thesis describes how the surface compositions of some alloys can be determined by Auger Electron Spectroscopy (AES). The motivation for this research and the reasons for the choice of alloy systems studied are formulated. The theoretical background of AES is briefly discussed and the apparatus used and the experimental procedures applied are described. Four alloy systems have been investigated in this thesis - Ni-Cu and Pd - Ag (consisting of a component active in most cataytic reactions - Ni and Pd; and a component which is almost inactive for a number of reactions - Cu and Ag) and Pt - Pd and Pt-Ir (consisting of two active components). Knowledge of the surface composition of the various alloy systems is shown to be essential for the interpretation of catalytic results. (Auth./C.F.)

  17. Calculation of thermodynamic properties of alloys of V-N system

    International Nuclear Information System (INIS)

    Concentration dependences of free energies of V2N and VN formation at 1473 and 1673 K are obtained on the basis of experimental data by phase equilibria in Cr-V-N system and available literary data on thermodynamics of limiting binary systems. It is noted that thermodynamic data from phase diagrams obtained by solving inverse problem are of much interest. Correctness of such approach is defined by adequate selection of phase thermodynamic models participating in equilibrium and also by reliability of experimental data used in calculation

  18. Inconel alloy 625 clad steel for application in wet scrubber systems

    International Nuclear Information System (INIS)

    Test panels from INCONEL 625 clad plate were successfully installed in two wet flue gas scrubber systems. In one system INCONEL 625 clad plate was located in the roof section of the absorber just ahead of the outlet ducting. The test plates, including weld seams, showed no signs to corrosion after six months of exposure. In the other scrubber test plates located in the outlet duct of an I.D. fan house, in the stack lining, and in the absorber quench area were unattacked after nine months

  19. Effect of substitutional element in the microstructure and hardness of Ti-Zr system alloys used as biomaterials; Efeito do elemento substitucional na microestrutura e dureza de ligas do sistema Ti-Zr para aplicacao como biomaterial

    Energy Technology Data Exchange (ETDEWEB)

    Correa, D.R.N.; Vicente, F.B.; Grandini, C.R., E-mail: diegornc@fc.unesp.b [Universidade Estadual Paulista (UNESP), Bauru, SP (Brazil). Lab. de Anelasticidade e Biomateriais

    2010-07-01

    New titanium alloys had been developed with the aim of obtaining materials with improved properties for application as biomaterial, and alloys of the Ti-Zr system are among those most promising. The objective of this study is to analyze the influence of the zirconium concentration on microstructure and hardness of the Ti-5Zr, Ti-10Zr and Ti-15Zr alloys. After arc-melting melting, the samples were analyzed by chemical and gas composition, and characterized by density measurements, optical microscopy, x-ray diffraction and hardness. The results showed a microstructure formed by alpha phase (hexagonal close-packed structure) and increased of hardness. (author)

  20. Study of fatigue and fracture behavior of NbCr{sub 2}-based alloys: Phase stability in Nb-Cr-Ni ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, J.H.; Liaw, P.K. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Materials Science and Engineering; Liu, C.T. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

    1997-12-01

    Phase stability in a ternary Nb-Cr-Ni Laves phase system was studied in this paper. Their previous study in NbCr{sub 2}-based transition-metal Laves phases has shown that the average electron concentration factor, e/a, is the dominating factor in controlling the phase stability of NbCr{sub 2}-based Laves phases when the atomic size ratios are kept identical. Since Ni has ten out-shell electrons, the substitution of Ni for Cr in NbCr{sub 2} will increase the average electron concentration of the alloy, thus leading to the change of the crystal structures from C15 to C14. In this paper, a number of pseudo-binary Nb(Cr,Ni){sub 2} alloys were prepared, and the crystal structures of the alloys after a long heat-treatment at 1000 C as a function of the Ni content were determined by the X-ray diffraction technique. The boundaries of the C15/C14 transition were determined and compared to their previous predictions. It was found that the electron concentration and phase stability correlation is obeyed in the Nb-Cr-Ni system. However, the e/a ratio corresponding to the C15/C14 phase transition was found to move to a higher value than the predicted one. The changes in the lattice constant, Vickers hardness and fracture toughness were also determined as a function of the Ni content, which were discussed in light of the phase stability difference of the alloys.

  1. Boundaries of the homologous phases in Sb–Te and Bi–Te binary alloy systems

    Energy Technology Data Exchange (ETDEWEB)

    Kifune, K., E-mail: k.kifune.yw@cc.it-hiroshima.ac.jp [Hiroshima Institute of Technology, Research Center for Condensed Matter Physics, 2-1-1 Miyake, Saeki-ku, Hiroshima 731-5193 (Japan); Tachizawa, T.; Kanaya, H.; Kubota, Y. [Osaka Prefecture University, Graduate School of Science, Osaka 599-8531 (Japan); Yamada, N. [Kyoto University, Department of Materials Science & Engineering, Kyoto 606-8501 (Japan); Matsunaga, T. [Panasonic Corporation, Advanced Research Division, Osaka 571-8501 (Japan)

    2015-10-05

    Highlights: • Phase boundary of the homologous phase in Sb–Te is fixed at Sb{sub 20}Te{sub 3} compound. • Crystal structure of Sb{sub 20}Te{sub 3} is refined by the 4D structure analysis. • Phase boundary of the homologous phase in Bi–Te is fixed at Bi{sub 8}Te{sub 3} compound. • Crystal structure of Bi{sub 8}Te{sub 3} is refined by the 4D structure analysis. • Difference between Sb–Te and Bi–Te systems are proposed. - Abstract: Sb–Te and Bi–Te binary systems have long-period stacking structures called homologous phases. Within these structures, two types of fundamental structural units change their numbers according to their composition, and the stacking periods also change systematically. X-ray powder diffraction data on bulk specimens with different compositions reveal both the phase boundaries of the homologous phases and the structures of the boundary phases. The boundary phases are Sb{sub 20}Te{sub 3} in the Sb–Te system and Bi{sub 8}Te{sub 3} in the Bi–Te system.

  2. The Ti-V-Fe ternary alloy system and its application to hydrogen storage

    International Nuclear Information System (INIS)

    In this work, the samples synthesized on a wide composition range of the system Ti-V-Fe have allowed to specify the isothermal section at 1000 C and to give data on the expansion of the centered cubic structure, attractive for hydrogen storage. (O.M.)

  3. New Tribo-systems for Cold Forming of Steel, Stainless Steel and Aluminium Alloys

    DEFF Research Database (Denmark)

    Bay, Niels

    2013-01-01

    Globalisation of industrial production and increasing demands for environmentally benign solutions has forced cold forging industry to search for new, economically optimized tribo-systems, which are less harmful to the working as well as the global environment. The present paper describes efforts...

  4. Magnetic transition in NiPt alloy systems: experiment and theory

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Uday [Laboratory for Condensed Matter Physics, S.N. Bose National Centre for Basic Sciences, JD Block, Sector 3, Salt Lake City, Kolkata 700098 (India); Padmalekha, K.G. [Department of Physics, Indian Institute of Science, Bangalore 560012 (India); Mukhopadhyay, P.K. [Laboratory for Condensed Matter Physics, S.N. Bose National Centre for Basic Sciences, JD Block, Sector 3, Salt Lake City, Kolkata 700098 (India)]. E-mail: pkm@bose.res.in; Paudyal, Durga [Condensed Matter Theory Group, S.N. Bose National Centre for Basic Sciences, JD Block, Sector 3, Salt Lake City, Kolkata 700098 (India)]. E-mail: dpaudyal@bose.res.in; Mookerjee, Abhijit [Condensed Matter Theory Group, S.N. Bose National Centre for Basic Sciences, JD Block, Sector 3, Salt Lake City, Kolkata 700098 (India)]. E-mail: abhijit@bose.res.in

    2005-04-15

    We report here the preparation and measurements on the susceptibility, sound velocity and internal friction for NiPt systems. We then compare these experimental results with the first principle theoretical predictions and show that there is reasonable agreement with experiment and theory.

  5. Comparison of secondary neutron dose in proton therapy resulting from the use of a tungsten alloy MLC or a brass collimator system

    International Nuclear Information System (INIS)

    Purpose: To apply the dual ionization chamber method for mixed radiation fields to an accurate comparison of the secondary neutron dose arising from the use of a tungsten alloy multileaf collimator (MLC) as opposed to a brass collimator system for defining the shape of a therapeutic proton field. Methods: Hydrogenous and nonhydrogenous ionization chambers were constructed with large volumes to enable measurements of absorbed doses below 10-4 Gy in mixed radiation fields using the dual ionization chamber method for mixed-field dosimetry. Neutron dose measurements were made with a nominal 230 MeV proton beam incident on a closed tungsten alloy MLC and a solid brass block. The chambers were cross-calibrated against a 60Co-calibrated Farmer chamber in water using a 6 MV x-ray beam and Monte Carlo simulations were performed to account for variations in ionization chamber response due to differences in secondary neutron energy spectra. Results: The neutron and combined proton plus γ-ray absorbed doses are shown to be nearly equivalent downstream from either a closed tungsten alloy MLC or a solid brass block. At 10 cm downstream from the distal edge of the collimating material the neutron dose from the closed MLC was (5.3 ± 0.4) x 10-5 Gy/Gy. The neutron dose with brass was (6.4 ± 0.7) x 10-5 Gy/Gy. Further from the secondary neutron source, at 50 cm, the neutron doses remain close for both the MLC and brass block at (6.9 ± 0.6) x 10-6 Gy/Gy and (6.3 ± 0.7) x 10-6 Gy/Gy, respectively. Conclusions: The dual ionization chamber method is suitable for measuring secondary neutron doses resulting from proton irradiation. The results of measurements downstream from a closed tungsten alloy MLC and a brass block indicate that, even in an overly pessimistic worst-case scenario, secondary neutron production in a tungsten alloy MLC leads to absorbed doses that are nearly equivalent to those seen from brass collimators. Therefore, the choice of tungsten alloy in constructing the

  6. Shape-memory alloy overload protection device for osseointegrated transfemoral implant prosthetic limb attachment system

    Science.gov (United States)

    Xu, Wei; Shao, Fei; Hughes, Steven

    2002-11-01

    The osseointegrated trans-femoral implant system provides a direct anchoring technique to attach prosthetic limb. This technique was first introduced PI Brenmark in Sweden. The UK had the first clinical trial in 1997 and currently has 6 active limb wearers. The success of this procedure has the potential for improved gait function and mobility, increased employability and significant long-term improvements in the quality of life for above knee amputees. However, the significant load involved in the trans-femoral implant system has caused permanent deformation and/or fractures of the implant abutment in several occasions. To protect the implant system, the implant abutment in particularly, an overloading protection device was introduced. The device uses mechanical mechanism to release torsion overload on the abutment. However, the bending overload protection remains unsolved. To solve the problem, a new overload protection device was developed. This device uses SMA component for bending overload protection. In this paper, the results of non-linear finite element modelling of the SMA and steel (AISI 1040) components were presented. Experiments were also carried out using steel components to assess the design which is based on the non-linear property of the materials.

  7. Development of an atomic mobility database for liquid phase in multicomponent Al alloys. Focusing on binary systems

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shaoqing; Du, Yong; Zhang, Lijun [Central South Univ., Changsha, Hunan (China). State Key Laboratory of Powder Metallurgy; Liu, Dandan [Central South Univ., Changsha, Hunan (China). State Key Laboratory of Powder Metallurgy; Central South Univ., Changsha, Hunan (China). School of Materials Science and Engineering; Chen, Qing; Engstroem, Anders [Thermo-Calc Software AB, Stockholm (Sweden)

    2013-08-15

    An atomic mobility database for binary liquid phase in multicomponent Al-Cu-Fe-Mg-Mn-Ni-Si-Zn alloys was established based on critically reviewed experimental and theoretical diffusion data by using DICTRA (Diffusion Controlled TRAnsformation) software. The impurity diffusivities of the elements with limited experimental data are obtained by means of the least-squares method and semi-empirical correlations. Comprehensive comparisons between the calculated and measured diffusivities indicate that most of the reported diffusivities can be well reproduced by the currently obtained atomic mobilities. The reliability of this diffusivity database is further validated by comparing the simulated concentration profiles with the measured ones, as well as the measured main inter-diffusion coefficients of liquid Al-Cu-Zn alloys with the extrapolated ones from the present binary atomic mobility database. The approach is of general validity and applicable to establish mobility databases of other liquid alloys. (orig.)

  8. Compositional characterization of Nb-1% Zr alloy used for the reactor vessel in space nuclear power systems by ICPOES

    International Nuclear Information System (INIS)

    Mira mist nebulizer of ICP-OES (Inductive Coupled Plasma-Optical Emission Spectrometer) in combination with argon humidifier and Teflon kit was used for quantitative determination of Nb, Zr, traces of Mg and Al in Nb-1%Zr alloy. This alloy is commonly used in space power applications where resistance to liquid alkali metal corrosion at temperatures near 1100 K is the primary concern. In addition to this, Nb-1% Zr alloy is also used in fabrication of various parts of space nuclear power reactor like vessel, heat pipe, and power components. It was observed that the addition of 1% zirconium to niobium greatly improved the creep strength over the soft pure metal. Thus Nb-1%Zr became the replacement for pure niobium in applications requiring the chemical resistance of niobium and a material with high melting temperature. Nb-1%Zr also has low thermal nuclear capture cross-section properties

  9. The relationship between chromium content and erosion-corrosion resistance of Fe-CrC alloy system

    International Nuclear Information System (INIS)

    In order to determine the influence of chromium on erosion-corrosion coefficient of alloy in acid media, experiments were performed with chromium content in the range of 12-33% in different typical erosion -corrosion environments such as solution of sand with free acid in pH 2-7. The erosion-corrosion coefficient was evaluated by Apparatus for abrasion-corrosion testing. Wear coefficient, K, was calculated by formula: K= Δ Metalon / Δ Malloy Testing results were showed that the alloy with composition (%): Cr = 28-30: C = 1.8-2.0: Mn = 2.5-3.0: is the optimum for manufacturing details resistant erosion-corrosion in media upto pH=2-3. This alloy is used successfully to produce details for sand-pumps, minerals processing cyclones

  10. 3D reconstruction and characterization of carbides in Ni-based high carbon alloy in a FIB-SEM system

    International Nuclear Information System (INIS)

    Dual beam focused ion beam scanning electron microscopes (FIB-SEMs) are well suited for characterizing micron and submicron size microstructural features in three dimensions throughout a serial-sectioning experiment. In this article, a FIB-SEM instrument was used to collect morphological, crystallographic, and chemical information for an Ni-Ta-Al-Cr alloy of high carbon content. The alloy has been designed to have excellent tribological properties at elevated temperatures. The morphology, spatial distribution, scale, and degree of interconnection of primary carbides in the Ni-Ta-Al-Cr-C alloy was assessed via serial sectioning in a casting cross-section. The 3D reconstructions showed that the primary carbides and dendrites were forming a dendrite surrounded by primary carbide network over the entire cross-section. Additionally, the morphology and spatial distribution of secondary carbides after heat treatment was determined.

  11. Synthesis of ferromagnetic Fe-based bulk glassy alloys in the Fe-Si-B-P-C system

    International Nuclear Information System (INIS)

    Multi-component Fe76P5(BxSiyCz)19 glassy alloys were fount to exhibit a distinct glass transition, followed by a supercooled liquid region before crystallization in a rather wide composition range. The largest value of the supercooled liquid region defined by the difference between the glass transition temperature (Tg) and crystallization temperature (Tx), ΔTx (=Tx - Tg) was 54 K for Fe76P5(Si0.3B0.5C0.2)19. Furthermore, the crystallization of the glassy alloy occurs through a single exothermic reaction, which means simultaneous precipitation of several kinds of crystallites leading to higher glassy forming ability (GFA) due to the necessity of the atomic rearrangement on a long range scale. By copper mold casting, bulk glassy alloy rods with diameters up to 3 mm were produced. The representative Fe76P5(B0.5Si0.3C0.2)19 alloy exhibits rather high saturation magnetization of 1.44 T with good soft-magnetic properties, i.e., low coercive force of 1.2 A/m, and high effective permeability of 17,600 at 1 kHz under a field of 1 A/m. The bulk glassy alloy also possesses superhigh fracture strength of 3700 MPa and Young's modulus of 185 GPa. This new ferromagnetic bulk glassy alloy simultaneously exhibiting high GFA, rather high saturation magnetization, excellent soft-magnetic properties and superhigh fracture strength is promising for future applications as not only functional but also structural material

  12. Experimental study of the Ca–Mg–Zn system using diffusion couples and key alloys

    Directory of Open Access Journals (Sweden)

    Yi-Nan Zhang, Dmytro Kevorkov, Florent Bridier and Mamoun Medraj

    2011-01-01

    Full Text Available Nine diffusion couples and 32 key samples were prepared to map the phase diagram of the Ca–Mg–Zn system. Phase relations and solubility limits were determined for binary and ternary compounds using scanning electron microscopy, electron probe microanalysis and x-ray diffraction (XRD. The crystal structure of the ternary compounds was studied by XRD and electron backscatter diffraction. Four ternary intermetallic (IM compounds were identified in this system: Ca3MgxZn15−x (4.6≤x≤12 at 335 °C, IM1, Ca14.5Mg15.8Zn69.7 (IM2, Ca2Mg5Zn13 (IM3 and Ca1.5Mg55.3Zn43.2 (IM4. Three binary compounds were found to have extended solid solubility into ternary systems: CaZn11, CaZn13 and Mg2Ca form substitutional solid solutions where Mg substitutes for Zn atoms in the first two compounds, and Zn substitutes for both Ca and Mg atoms in Mg2Ca. The isothermal section of the Ca–Mg–Zn phase diagram at 335 °C was constructed on the basis of the obtained experimental results. The morphologies of the diffusion couples in the Ca–Mg–Zn phase diagram at 335 °C were studied. Depending on the terminal compositions of the diffusion couples, the two-phase regions in the diffusion zone have either a tooth-like morphology or contain a matrix phase with isolated and/or dendritic precipitates.

  13. Corrosion of aluminum alloys as a function of alloy composition

    International Nuclear Information System (INIS)

    A study was initiated which included nineteen aluminum alloys. Tests were conducted in high purity water at 3600C and flow tests (approx. 20 ft/sec) in reactor process water at 1300C (TF-18 loop tests). High-silicon alloys and AlSi failed completely in the 3600C tests. However, coupling of AlSi to 8001 aluminum suppressed the failure. The alloy compositions containing iron and nickel survived tht 3600C autoclave exposures. Corrosion rates varied widely as a function of alloy composition, but in directions which were predictable from previous high-temperature autoclave experience. In the TF-18 loop flow tests, corrosion penetrations were similar on all of the alloys and on high-purity aluminum after 105 days. However, certain alloys established relatively low linear corrosion rates: Al-0.9 Ni-0.5 Fe-0.1 Zr, Al-1.0 Ni-0.15 Fe-11.5 Si-0.8 Mg, Al-1.2 Ni-1.8 Fe, and Al-7.0 Ni-4.8 Fe. Electrical polarity measurements between AlSi and 8001 alloys in reactor process water at temperatures up to 1500C indicated that AlSi was anodic to 8001 in the static autoclave system above approx. 500C

  14. Oxygen partial pressure: a key to alloying and discovery in metal oxide--metal eutectic systems

    International Nuclear Information System (INIS)

    Control of oxygen partial pressure is essential in the directional solidification of oxide--metal eutectic composites by techniques involving gas-solid and gas-liquid interactions. The existence of end components in the eutectic composite is Po2 sensitive as are melt stoichiometry, solid phase compositions, and vapor losses due to oxidation-volatilization. Simple criteria are postulated which can aid the experimentalist in selecting the proper gas mixture for oxide--metal eutectic composite growth. The Cr2O3--Mo--Cr systems was used to verify certain aspects of the proposed criteria

  15. Integration of Shape Memory Alloys into Low-Damped Rotor-Bearing Systems

    DEFF Research Database (Denmark)

    Enemark, Søren

    2015-01-01

    employed, and modifications are made to two subparts dealing with the evolution of phase transformations. By using the modifications, it is possible to reproduce experimental observations with higher accuracy. Uncertainty analysis of material parameters is a general theme of the thesis in order to ensure...... passive magnetic bearings. A holistic and multidisciplinary approach is used for modelling the system, linking the nonlinear SMA spring, the weakly nonlinear passive magnetic bearings, and the dynamic interaction between the rotor and bearing housings. Theoretical and experimental results show that it is...

  16. Hydrogen four-level tunnel systems in substitutional body-centred cubic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Cordero, F. [CNR, Area di Ricerca di Roma - Tor Vergata, Ist. di Acustica ' ' O. M. Corbino' ' , Roma (Italy); INFM (Italy); Cantelli, R. [INFM (Italy); Univ. di Roma ' ' La Sapienza' ' , Dipt. di Fisica, Roma (Italy)

    2002-10-01

    A brief account is provided of the main results of a study of the tunneling states of H trapped by substitutional (S) impurities in Nb, mainly consisting in anelasticity experiments. The phenomenology is rather complex when the concentration of S atoms is higher than a few parts per thousand, and various and contrasting interpretations are possible. The complication arises from the destruction of the symmetry of the S-H pair by the elastic interactions among the defects. The situation becomes, however, clear for an S content around 0.1%, when the anelastic spectra reveal the relaxation processes due to the now nearly undistorted S-H complexes. In this case H delocalizes over four tetrahedral sites of a face of the cube containing the S atom, giving rise to a four-level tunnel system (FLS). The parameters of tunneling and coupling to phonons and electron excitations are similar to those found for the two-level system of H near an interstitial impurity, but new effects are found, due to the symmetry of the additional eigenstates of a centrosymmetric FLS. (orig.)

  17. Magnetic properties of the alloys system CuAl1-xCrxS2 (x = 0.50, 0.75)

    International Nuclear Information System (INIS)

    The synthesis, structural characterization and magnetic properties of alloy system CuAl1-xCrxS2 (x = 0.50, 075) are reported. The samples were synthesized by using the direct fusion technique. The chemical analysis (EDX) confirmed the stoichiometric ratio for the concentrations. The powder diffraction patterns were indexed and the principal phases crystallizes with tetragonal symmetry with unit cell parameters a = 5.312(1) A, c = 10.389(2) A for x = 0.50 and a = 5.314(2) A, c = 10.393(2) A for x = 0.75. These alloys behave as antiferromagnetic, with Neel temperature of 37 K and 39 K, respectively. The EPR linewidth for these alloys shows a paramagnetic behavior between 100 and 610 K. The resonance field and the g factor show a slight variation with temperature. These results are discussed in terms of nearest-neighbor Cr+3 (S=3/2) spin-coupled pairs. (Author)

  18. In-situ and real-time investigation of the columnar-equiaxed transition in the transparent alloy system neopentylglycol-camphor onboard the sounding rocket TEXUS-47

    Science.gov (United States)

    Sturz, L.; Zimmermann, G.

    2011-12-01

    The low-gravity experiment TRACE (TRansparent Alloys in Columnar Equiaxed solidification) has been performed onboard the sounding rocket TEXUS-47 to enable the investigation of dendritic growth and the dendrites' columnar to equiaxed transition during solidification. Low-gravity conditions provide solidification under diffusive heat and mass transfer conditions and without sedimentation or buoyancy of equiaxed dendrites or nucleation seeds to simplify the boundary conditions for dendritic microstructure simulation. In addition the transparent organic alloy system Neopentylglycol (NPG) - (D)Camphor (DC) was used to allow for a real-time and in-situ observation of the microstructure evolution with standard optics. For the flight experiment all relevant experimental parameters like thermal gradient, solidification velocity and undercooling within the bulk liquid and at the columnar dendritic tips have been determined by image analysis or from thermocouple recordings within the solidifying alloy. This allows a very detailed comparison with results of existing models for dendritic growth and for columnar-to-equiaxed transition. Here we present a summary of the experimental findings in comparison with results of some of the theoretical models.

  19. Design of a planar probe diagnostic system for plasmatron VISIONI and its application for the study of deuterium retention in W-Ta alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zayachuk, Y., E-mail: yzayachu@sckcen.be [SCK-CEN, Boeretang 200, 2400 Mol (Belgium); Department of Applied Physics, Ghent University, Plateaustraat 22, 9000 Ghent (Belgium); Bousselin, G.; Schuurmans, J. [SCK-CEN, Boeretang 200, 2400 Mol (Belgium); Gasparyan, Yu. [National Research Nuclear University ' MEPhI' , Kashirskoe shosse 31, 115409 Moscow (Russian Federation); Uytdenhouwen, I. [SCK-CEN, Boeretang 200, 2400 Mol (Belgium); Van Oost, G. [Department of Applied Physics, Ghent University, Plateaustraat 22, 9000 Ghent (Belgium)

    2011-10-15

    One of the issues still to be clarified with respect to the possible use of tungsten and tungsten alloys as first wall material in fusion reactors is the retention of hydrogen isotopes under fusion-relevant conditions, such as the presence of helium ash, neutron irradiation, thermal shock. The low flux, high temperature plasma simulator VISIONI, being currently constructed at the Belgian nuclear research center SCK.CEN, will have the unique ability to handle radioactive materials - neutron irradiated samples and tritium plasma. Currently it is being tested with non-irradiated samples and deuterium plasma. To monitor the plasma parameters near the investigated specimen, a planar probe system has been developed. It was demonstrated that the plasmatron is able to provide conditions relevant for the ITER first wall. Investigations of deuterium retention in W-Ta alloys have been performed, using thermodesorption spectroscopy. A hypothesis of the existence of three kinds of trapping sites for deuterium in W-Ta alloys, based on deuterium release studies, is suggested.

  20. Imparting passivity to vapor deposited magnesium alloys

    Science.gov (United States)

    Wolfe, Ryan C.

    Magnesium has the lowest density of all structural metals. Utilization of low density materials is advantageous from a design standpoint, because lower weight translates into improved performance of engineered products (i.e., notebook computers are more portable, vehicles achieve better gas mileage, and aircraft can carry more payload). Despite their low density and high strength to weight ratio, however, the widespread implementation of magnesium alloys is currently hindered by their relatively poor corrosion resistance. The objective of this research dissertation is to develop a scientific basis for the creation of a corrosion resistant magnesium alloy. The corrosion resistance of magnesium alloys is affected by several interrelated factors. Among these are alloying, microstructure, impurities, galvanic corrosion effects, and service conditions, among others. Alloying and modification of the microstructure are primary approaches to controlling corrosion. Furthermore, nonequilibrium alloying of magnesium via physical vapor deposition allows for the formation of single-phase magnesium alloys with supersaturated concentrations of passivity-enhancing elements. The microstructure and surface morphology is also modifiable during physical vapor deposition through the variation of evaporation power, pressure, temperature, ion bombardment, and the source-to-substrate distance. Aluminum, titanium, yttrium, and zirconium were initially chosen as candidates likely to impart passivity on vapor deposited magnesium alloys. Prior to this research, alloys of this type have never before been produced, much less studied. All of these metals were observed to afford some degree of corrosion resistance to magnesium. Due to the especially promising results from nonequilibrium alloying of magnesium with yttrium and titanium, the ternary magnesium-yttrium-titanium system was investigated in depth. While all of the alloys are lustrous, surface morphology is observed under the scanning

  1. Hydride storage systems consisting of Al alloys for the decoupling of heat and electricity; Hydridspeicher aus Al-Legierungen zur Entkopplung von Waerme und Strom

    Energy Technology Data Exchange (ETDEWEB)

    Urbanczyk, Robert; Peil, Stefan [Institut fuer Energie- und Umwelttechnik e.V., Duisburg (Germany); Peinecke, Kateryna; Felderhoff, Michael; Hauschild, Klaus [Max-Planck-Institut fuer Kohlenforschung, Muelheim an der Ruhr (Germany)

    2012-07-01

    The authors of the contribution under consideration report on the development of a H{sub 2} solid state storage system consisting of aluminium alloys. The storage system was assembled from an extruded round rod consisting of the Aluminium alloy EN AW 6082 T6. Also an extruded heat transmission structure consisting of EN AW 6060 T6 was used as a bayonet heat exchanger. The heat transfer medium consisted of a circulating thermal oil. The storage system was filled with a complex metal hydride Na{sub 3}AlH{sub 6} and operated in several cycles of hydrogenation and dehydrogenation. Theoretically, Na{sub 3}AlH{sub 6} stores 3 mass-% hydrogen and is hydrogenated and dehydrogenated at lower pressures in contrast to the dehydrogenation preliminary stage NaAlH{sub 4}. The storage material was dehydrogenated at a temperature of nearly 180 Celsius and at a pressure of 15 bar H{sub 2}. The authors discuss the operation of the storage system in stationary applications. Stationary storage systems can be produced in a simply manner and in large quantities by means of the implanted extrusion process.

  2. A New Method for Low Cost Production of Titanium Alloys for Reducing Energy Consumption of Mechanical Systems

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Z. Zak [Univ. of Utah, Salt Lake City, UT (United States); Chandran, Ravi [Univ. of Utah, Salt Lake City, UT (United States); Koopman, Mark [Univ. of Utah, Salt Lake City, UT (United States)

    2016-02-29

    This project investigated an innovative manufacturing process intended to minimize the cost of production of titanium materials and components, and increase the adoption of Ti components for energy consuming applications, such as automobiles. A key innovation of the proposed manufacturing approach is a novel Ti powder sintering technology for making titanium materials with ultrafine grain microstructure in the as-sintered state with minimum, or an absence, of post-sintering processes. The new sintering technology is termed Hydrogen Sintering and Phase Transformations (HSPT), and constitutes a promising manufacturing technology that can be used to produce titanium (Ti) materials and components in a near-net-shape form, thus also minimizing machining costs. Our objective was to meet, or possibly surpass, the mechanical property levels for ASTM B348 Grade 5 for wrought Ti-6Al-4V. Although specific applications call for varying mechanical property requirements, ASTM B348 was created for the demanding applications of the aerospace industry, and is the established standard for Ti-6Al-4V. While the primary goal was to meet, or exceed this standard, the team also had the goal of demonstrating this could be done at a significantly lower cost of production. Interim goals of the project were to fully develop this novel sintering process, and provide sufficient baseline testing to make the method practical and attractive to industry. By optimizing the process parameters for the sintering of titanium hydride (TiH2) powders in a hydrogen atmosphere and controlling the phase transformations during and after sintering, the HSPT process was expected to reduce the energy consumption, and thus cost, of making Ti alloys and fabricating Ti components. The process was designed such that no high temperature melting is required for producing Ti alloys; little or no post-sintering processing is needed for producing desired microstructures (and therefore enhanced mechanical

  3. Effect of radiolysis on long-term corrosion system formed on low-alloy steels

    International Nuclear Information System (INIS)

    In France, for nuclear waste management, it is planned to build a storage device with a barrier system composed of steel container. Corrosion is evaluated for the safety of anoxic storage over the long term. With radiation, water radiolysis generates oxidizing and reducing species that can change the corrosion. Three aspects are developed in this thesis. The first concerns iron coupon samples experimented in carbonate deaerated water and subjected to gamma irradiation. It is shown that irradiation can increase corrosion rates within the parameters of dose. Identified crystalline phases are little changed with irradiation. Solution chemistry shows a decrease in pH with dose related to iron. Organic species are identified. The second axis is archaeological analogues irradiation with an old corrosion products layer. Structural analysis verified the phase stability with radiolysis, only the newly formed products changes. The third axis is a kinetic simulation approach. It checks the pH drop under irradiation. Taken together, these results allow us to provide new data for the anoxic corrosion under irradiation. (author)

  4. Assessing the Effects of Radiation Damage on Ni-base Alloys for the Prometheus Space Reactor System

    Energy Technology Data Exchange (ETDEWEB)

    T. Angeliu

    2006-01-19

    Ni-base alloys were considered for the Prometheus space reactor pressure vessel with operational parameters of {approx}900 K for 15 years and fluences up to 160 x 10{sup 20} n/cm{sup 2} (E > 0.1 MeV). This paper reviews the effects of irradiation on the behavior of Ni-base alloys and shows that radiation-induced swelling and creep are minor considerations compared to significant embrittlement with neutron ,exposure. While the mechanism responsible for radiation-induced embrittlement is not fully understood, it is likely a combination of helium embrittlement and solute segregation that can be highly dependent on the alloy composition and exposure conditions. Transmutation calculations show that detrimental helium levels would be expected at the end of life for the inner safety rod vessel (thimble) and possibly the outer pressure vessel, primarily from high energy (E > 1 MeV) n,{alpha} reactions with {sup 58}Ni. Helium from {sup 10}B is significant only for the outer vessel due to the proximity of the outer vessel to the Be0 control elements. Recommendations for further assessments of the material behavior and methods to minimize the effects of radiation damage through alloy design are provided.

  5. Assessing the Effects of Radiation Damage on Ni-base Alloys for the Prometheus Space Reactor System

    International Nuclear Information System (INIS)

    Ni-base alloys were considered for the Prometheus space reactor pressure vessel with operational parameters of ∼900 K for 15 years and fluences up to 160 x 1020 n/cm2 (E > 0.1 MeV). This paper reviews the effects of irradiation on the behavior of Ni-base alloys and shows that radiation-induced swelling and creep are minor considerations compared to significant embrittlement with neutron exposure. While the mechanism responsible for radiation-induced embrittlement is not fully understood, it is likely a combination of helium embrittlement and solute segregation that can be highly dependent on the alloy composition and exposure conditions. Transmutation calculations show that detrimental helium levels would be expected at the end of life for the inner safety rod vessel (thimble) and possibly the outer pressure vessel, primarily from high energy (E > 1 MeV) n,α reactions with 58Ni. Helium from 10B is significant only for the outer vessel due to the proximity of the outer vessel to the BeO control elements. Recommendations for further assessments of the material behavior and methods to minimize the effects of radiation damage through alloy design are provided

  6. Assessing the Effects of Radiation Damage on Ni-base Alloys for the Prometheus Space Reactor System

    Energy Technology Data Exchange (ETDEWEB)

    T Angeliu; J Ward; J Witter

    2006-04-04

    Ni-base alloys were considered for the Prometheus space reactor pressure vessel with operational parameters of {approx}900 K for 15 years and fluences up to 160 x 10{sup 20} n/cm{sup 2} (E > 0.1 MeV). This paper reviews the effects of irradiation on the behavior of Ni-base alloys and shows that radiation-induced swelling and creep are minor considerations compared to significant embrittlement with neutron exposure. While the mechanism responsible for radiation-induced embrittlement is not fully understood, it is likely a combination of helium embrittlement and solute segregation that can be highly dependent on the alloy composition and exposure conditions. Transmutation calculations show that detrimental helium levels would be expected at the end of life for the inner safety rod vessel (thimble) and possibly the outer pressure vessel, primarily from high energy (E > 1 MeV) n,{alpha} reactions with {sup 58}Ni. Helium from {sup 10}B is significant only for the outer vessel due to the proximity of the outer vessel to the BeO control elements. Recommendations for further assessments of the material behavior and methods to minimize the effects of radiation damage through alloy design are provided.

  7. Bulk amorphous Mg-based alloys

    DEFF Research Database (Denmark)

    Pryds, Nini

    The present paper describes the preparation and properties of bulk amorphous quarternary Mg-based alloys and the influence of additional elements on the ability of the alloy to form bulk amorphous. The main goal is to find a Mg-based alloy system which shows both high strength to weight ratio and a...... low glass transition temperature. The alloys were prepared by using a relatively simple technique, i.e. rapid cooling of the melt in a copper wedge mould. The essential structural changes that are achieved by going from the amorphous to the crystalline state through the supercooled liquid state are...... discussed in this paper. On the basis of these measurements phase diagrams of the different systems were constructed. Finally, it is demonstrated that when pressing the bulk amorphous alloy onto a metallic dies at temperatures within the supercooled liquid region, the alloy faithfully replicates the surface...

  8. Copper-based alloys, crystallographic and crystallochemical parameters of alloys in binary systems Cu-Me (Me=Co, Rh, Ir, Cu, Ag, Au, Ni, Pd, Pt)

    International Nuclear Information System (INIS)

    The article presents the results of the analysis of phase equilibrium of ordered phases in binary systems based on copper Cu- Me (where Me - Co, Rh, Ir, Ag, Au, Ni, Pd, Pt) to find correlations of crystallochemical and crystallographic factors. It is established that the packing index in disordered solid solutions in binary systems based on copper is close to the value of 0.74 against the background of an insignificant deviation of atomic volumes from the Zen’s law

  9. Copper-based alloys, crystallographic and crystallochemical parameters of alloys in binary systems Cu-Me (Me=Co, Rh, Ir, Cu, Ag, Au, Ni, Pd, Pt)

    Science.gov (United States)

    Porobova, Svetlana; Markova, Tat'jana; Klopotov, Vladimir; Klopotov, Anatoliy; Loskutov, Oleg; Vlasov, Viktor

    2016-01-01

    The article presents the results of the analysis of phase equilibrium of ordered phases in binary systems based on copper Cu- Me (where Me - Co, Rh, Ir, Ag, Au, Ni, Pd, Pt) to find correlations of crystallochemical and crystallographic factors. It is established that the packing index in disordered solid solutions in binary systems based on copper is close to the value of 0.74 against the background of an insignificant deviation of atomic volumes from the Zen's law.

  10. Copper-based alloys, crystallographic and crystallochemical parameters of alloys in binary systems Cu-Me (Me=Co, Rh, Ir, Cu, Ag, Au, Ni, Pd, Pt)

    Energy Technology Data Exchange (ETDEWEB)

    Porobova, Svetlana, E-mail: porobova.sveta@yandex.ru; Loskutov, Oleg, E-mail: lom58@mail.ru [Tomsk State University of Architecture and Building, Russia, Tomsk, 2 Solyanaya sq, Tomsk, 634003 (Russian Federation); Markova, Tat’jana, E-mail: patriot-rf@mail.ru [Siberian State Industrial University. 42 Kirov St., Novokuznetsk, 654007 (Russian Federation); Klopotov, Vladimir, E-mail: vdklopotov@mail.ru [Research Tomsk Polytechnic University, 30 Lenin Ave., Tomsk, 634050 (Russian Federation); Klopotov, Anatoliy, E-mail: klopotovaa@tsuab.ru [Tomsk State University of Architecture and Building, Russia, Tomsk, 2 Solyanaya sq, Tomsk, 634003 (Russian Federation); National Research Tomsk State University, 36, Lenin Ave., Tomsk, 634050 (Russian Federation); Vlasov, Viktor, E-mail: vik@tsuab.ru [Tomsk State University of Architecture and Building, Russia, Tomsk, 2 Solyanaya sq, Tomsk, 634003 (Russian Federation); Research Tomsk Polytechnic University, 30 Lenin Ave., Tomsk, 634050 (Russian Federation)

    2016-01-15

    The article presents the results of the analysis of phase equilibrium of ordered phases in binary systems based on copper Cu- Me (where Me - Co, Rh, Ir, Ag, Au, Ni, Pd, Pt) to find correlations of crystallochemical and crystallographic factors. It is established that the packing index in disordered solid solutions in binary systems based on copper is close to the value of 0.74 against the background of an insignificant deviation of atomic volumes from the Zen’s law.

  11. {332}〈113〉 Twinning system selection in a β-type Ti–15Mo–5Zr polycrystalline alloy

    International Nuclear Information System (INIS)

    The orientational dependence of {332}〈113〉 twinning and its system was examined in a 4.0% tensile-strained Ti–15Mo–5Zr (mass%) polycrystalline alloy by electron backscatter diffraction analysis combined with Schmid factor analysis. Twinning and system selections were found to obey the Schmid law in grains with tensile axes close to the [1-bar 11] and [001] directions, in which the maximum Schmid factors of an easily operative (233)[3-bar 11] twinning system were larger than 0.46 and smaller than 0.34, respectively. However, when the maximum Schmid factor ranged from 0.34 to 0.46, both selections became complex and not entirely explainable by the Schmid law around the center of a stereographic triangle. Twinning systems other than (233)[3-bar 11] were also activated in grains with a Schmid factor even below 0.1 and inside twins with a negative Schmid factor. We conclude that additional factors, specifically local stress concentrations and geometric constraints between neighboring grains, should also be considered in regard to {332}〈113〉 twin formation, even in a polycrystalline β-titanium alloy that has been only slightly deformed

  12. Vanadium alloys: development strategy

    International Nuclear Information System (INIS)

    A strategy for the development of vanadium alloys for use in radiation environments is outlined. An attractive reference alloy (V-15Cr-5Ti) has been identified. The critical issues in developing vanadium base alloys are summarized

  13. Surface Bond Strength in Nickel Based Alloys

    OpenAIRE

    Ramesh, Ganesh; Padmanabhan, T. V.; Ariga, Padma; Joshi, Shalini; Bhuminathan, S.; Vijayaraghavan, Vasantha

    2012-01-01

    Bonding of ceramic to the alloy is essential for the longevity of porcelain fused to metal restorations. Imported alloys used now a days in processing them are not economical. So this study was conducted to evaluate and compare the bond strength of ceramic material to nickel based cost effective Nonferrous Materials Technology Development Center (NFTDC), Hyderabad and Heraenium S, Heraeus Kulzer alloy. An Instron testing machine, which has three-point loading system for the application of loa...

  14. A bidirectional shape memory alloy folding actuator

    OpenAIRE

    Paik, Jamie; Wood, Robert J.

    2012-01-01

    This paper presents a low-profile bidirectional folding actuator based on annealed shape memory alloy sheets applicable for meso-and microscale systems. Despite the advantages of shape memory alloys-high strain, silent operation, and mechanical simplicity-their application is often limited to unidirectional operation. We present a bidirectional folding actuator that produces two opposing 180 degrees motions. A laser-patterned nickel alloy (Inconel 600) heater localizes actuation to the foldin...

  15. Mapping between Alloy specifications and database implementations

    OpenAIRE

    Cunha, Alcino; Pacheco, Hugo

    2009-01-01

    The emergence of lightweight formal methods tools such as Alloy improves the software design process, by encouraging developers to model and verify their systems before engaging in hideous implementation details. However, an abstract Alloy specification is far from an actual implementation, and manually refining the former into the latter is unfortunately a non-trivial task. This paper identifies a subset of the Alloy language that is equivalent to a relational database schema with the most c...

  16. Use of flux welding slag of the Mn-O-SiO2 system for the obtaining of a new alloyed agglomerated flux

    International Nuclear Information System (INIS)

    This paper deals with the use of welding slags of the MnO-SiO2 system fluxes, coming from the recovering by means of the submerged arc welding in the manufacturing of agglomerated fluxes for surfacing with the same propose. the composition of the matrix is studied by means of an experimental design in a restricted area of the Mc Lean Anderson kind, the technological behaviour of the different mixtures is checked, and the results of the best types that have alloy charges included are analysed by a characterization of the weld. (Author) 20 refs

  17. Separation factors of U and Pr or Nd in LiCl-KCl-CsCl melt – Liquid gallium, indium or galliumindium eutectic alloy system

    International Nuclear Information System (INIS)

    Metals of the third group of the periodic table and their alloys are promising systems for separating components of spent nuclear fuel (SNF) during its pyrochemical reprocessing. Radiation stability of this metals allow reprocessing a high burn-up fuel of fast neutron reactors after a relatively short cooling time, while low melting points (29.77 ° for Ga, 156.78 ° for In and 15.3 ° for the Ga-In eutectic) allow working in a wide temperature range

  18. The effect of silicide ceramic coatings on the high-temperature strength and plasticity of niobium alloys of the Nb-W-Mo-Zr system

    International Nuclear Information System (INIS)

    A study is made into short-term rupture strength and plasticity of 5VMTs alloy of Nb-W-Mo-Zr system and a 5VMTs-silicide ceramic coating composite material in vacuum, inert environment and in the air within a temperature range of 290-2070 K. The kinetics of defect generation and development both in the protective coating and the matrix is studied. The values of limiting plastic strains are determined at which the composite materials preserves its carrying capacity in high temperature aggressive and oxidizing gaseous media

  19. Preparation of Mg-Ti System Alloy and FGM with Density Gradient by Spark Plasma Sintering Technique

    Institute of Scientific and Technical Information of China (English)

    SHEN Qiang; ZHANG Lian-meng; TAN Hua; JING Fu-qian

    2004-01-01

    A new kind of functionally graded materials (FGM) with density gradient has come to showgreat potentials as flier-plates for creating quasi- isotropic compression waves. In order to meet the demand of lowerdensity in the front face for sueh fiier-plate, Mg with a low density of 1.74g/cm3 is selected to make a Mg-TiFGM. Mg- Ti alloys with various weight ratios were sintered by spark plasma sintering (SPS) technique at relativelow temperatures, and the processing of densification is mainly investigated. It is found that, up to 75wt% Ti, theMg- Ti alloys can be fully deasified at 560℃ due to the conglutination of Mg and the formation of a small amountof Mg- Ti solid solution. Finally, the Mg- Ti FGM with a density gradient from 1.74g/cm3 to 3.23g/cm3 is suc-cessfully fabricated.

  20. Experience with detection and disposition of PWSCC flaws in PWR pressurizer and reactor coolant system loop Alloy 600 penetrations

    International Nuclear Information System (INIS)

    The discovery of cracking of alloy 600 heater sleeve penetrations in a Combustion Engineering (CE) designed pressurizer in 1989, prompted utilities and the designer to form a group to investigate the cracking and address the potential safety concerns. The cause of cracking was determined to be axial primary water stress corrosion cracking (PWSCC). Its axial orientation made ejection of a penetration highly unlikely. Therefore, PWSCC of alloy 600 penetrations was not considered a safety issue but an economic issue. To manage the issue at the Florida Power and Light Co.'s (FPL's) two unit St. Lucie Nuclear Power Plant, FPL has: performed visual inspections for evidence of PWSCC (leakage), preventively replaced penetrations based on predictions from industry data, and developed a standardized repair method as a contingency to respond to emergent repairs while minimizing the associated outage time

  1. A Study of the effect of gamma radiation on some alloy materials for use as dosimetry systems and its applications

    International Nuclear Information System (INIS)

    Alloys are metallic materials consisting of two or more elements combined in such a way that they cannot be readily separated by physical means. More than 90% of metals used are in the form of alloys. Alloys can be divided into two types: ferrous and non- ferrous. In metallurgy, a nonferrous metal is any metal that is not ferrous, including alloys, that does not contain iron in appreciable amounts. Groups of inorganic glassy materials which always contain one or more of the chalcogen elements S, Se or Te, in conjunction with more electropositive elements as As, Sb and Bi, are recognized as chalcogenide glasses but Ferroalloy refers to various alloys of iron with a high proportion of one or more other elements, for example ferrotitanium alloy. Chalcogenide glasses are generally less robust, more weakly bonded materials than oxide glasses. Glasses were prepared from Ge, Se, As and Te elements with purity 99.999%.These glasses are reactive at high temperature with oxygen. Therefore, synthesis was accomplished in evacuated clean silica tubes. The tubes were washed by distilled water, and then dried in a furnace whose temperature was about 100 degree C. The weighted materials were introduced into the cleaned silica tubes and then evacuated to about 10-4 torr and sealed. The sealed tubes were placed inside the furnace and the temperature of the furnace was raised gradually up to 900 degree C within 1 hour and kept constant for 10 hours. Moreover, shaking of the constituent materials inside the tube in the furnace was necessary for realizing the homogeneity of the composition. After synthesis, the tube was quenched into ice water. The glassy ingots could be obtained by drastic quenching. Then materials were removed from the tubes and kept in dry atmosphere. Thin films of the selected compositions were prepared by thermal evaporation technique under vacuum 10-4 torr with constant thickness 100 nm. Ferrotitanium alloy is prepared by the reduction of rutile and ilmenite ores

  2. Correlations between IMC thickness and three factors in Sn-3Ag-0.5Cu alloy system

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The effects of Ni content, soldering temperature and time on the IMC thickness in Sn-3Ag-0.5Cu and Sn-3Ag-0.5Cu-0.2Co alloys were researched using uniform design method and computer programs. For each alloy, the factors were divided into three levels in the experiment. Two correlative equations are given by regression. They indicate that the effects of three factors on the function are in the mutual and quadratic forms. And the analysis of variance shows the equations are sound and meaningful. Using the equations, it is easy to search, predict and control the IMC thickness. The existence of element Co accelerates the crystallization and growing up of IMC.

  3. Brazing technology of Ti alloy/stainless steel dissimilar metal joint at system integrated modular advanced reactor

    International Nuclear Information System (INIS)

    For the technoldogy development of brazing Ti alloy to stainless steel joints used at SMART, the status of brazing technology development, brazing processes, and the brazing technology of Ti alloy and stainless steel are reviewed. Because fusion welding process cannot be applied due to the formation of intermetallic compounds in the weld metal, brazing joint was selected at the design. The joint part is assembled with a thread composed with male part of Ti alloy tube and female part of stainless tube. The gap in the thread will be filled with brazing filler metal. However, brittle Ti-Fe intermetallic compounds are formed at the surface of stainless steel through the diffusion of Ti at the melt. Brazing conditions should be set-up to reduce the formation of intermetallic compounds. For that, 3 kinds of Ag filler metals were selected as the candidates and heating will be done with induction and electric furnaces. Through measuring of joint strength according to the control of pre- and post-braze treatment, heating rate and heating time, optimal brazing method will be fixed. To qualify the brazing procedure and performance and to check defects in final product, the inspection plan will be established according to the req2wuirements of AWS and ASME

  4. Effect of antimony on the corrosion behavior of low-alloy steel for flue gas desulfurization system

    International Nuclear Information System (INIS)

    The alloying effect of Sb in a new low-alloy steel for the purpose of FGD materials was investigated by potentiodynamic polarization, linear polarization resistance measurement, electrochemical impedance spectroscopy (EIS) and weight loss measurements in an aggressive solution of 16.9 vol.% H2SO4 + 0.35 vol.% HCl (modified green death solution) at 60 deg. C, pH -0.3. All measurements confirmed the marked improvement in the corrosion behavior of the low-alloy steel via the addition of a small amount of Sb, particularly for the 0.10Sb steel. Pitting corrosion was detected by scanning electron microscopy (SEM) on the surface of blank steel and 0.05Sb steel, but not 0.10Sb steel, after weight loss measurements. X-ray photoelectron spectroscopy (XPS) analysis of the corroded surfaces after EIS and linear polarization measurements showed that the decrease in corrosion rates was due to the formation of a protective Sb2O5 oxide film on the surface of the Sb-containing steels. Moreover, the addition of 0.10% Sb stimulated the development of high corrosion inhibiting, Cu-containing compounds which further inhibited the anodic and cathodic reactions

  5. Improving microstructure and ductility in the Mg–Zn alloy system by combinational Ce–Ca microalloying

    Energy Technology Data Exchange (ETDEWEB)

    Langelier, B.; Nasiri, A.M. [Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Avenue West, Ontario, Canada N2L 3G1 (Canada); Lee, S.Y. [Department of Materials Science and Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Gharghouri, M.A. [Canadian Neutron Beam Centre, Chalk River Laboratories, Chalk River, Ontario, Canada K0J 1J0 (Canada); Esmaeili, S. [Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Avenue West, Ontario, Canada N2L 3G1 (Canada)

    2015-01-03

    A strategy is proposed to enhance the microstructure and mechanical properties of Mg–Zn alloys by combining microalloying additions of the rare earth element Ce and the non-rare earth element Ca. The double additions of Ce–Ca are found to significantly increase tensile elongation compared to binary Mg–Zn, or single additions of either Ce or Ca. Microstructure analysis reveals that the Ce–Ca additions increase ductility by modifying texture and refining grain size. Texture modification is attributed to solute effects from the microalloying elements, particularly Ca, while grain refinement is additionally influenced by a fine dispersion of Mg{sub 6}Ca{sub 2}Zn{sub 3} precipitates that form during rolling and pin grain boundaries. The microalloying element additions also lead to large secondary phase particles in the alloys, which can limit ductility enhancement by promoting early fracture. By scaling Zn content in the Mg–Zn–Ce–Ca alloys, the Mg{sub 6}Ca{sub 2}Zn{sub 3} phase fraction and Zn solute content can be controlled for optimum ductility or strengthening potential.

  6. A lightweight shape-memory magnesium alloy

    Science.gov (United States)

    Ogawa, Yukiko; Ando, Daisuke; Sutou, Yuji; Koike, Junichi

    2016-07-01

    Shape-memory alloys (SMAs), which display shape recovery upon heating, as well as superelasticity, offer many technological advantages in various applications. Those distinctive behaviors have been observed in many polycrystalline alloy systems such as nickel titantium (TiNi)–, copper-, iron-, nickel-, cobalt-, and Ti-based alloys but not in lightweight alloys such as magnesium (Mg) and aluminum alloys. Here we present a Mg SMA showing superelasticity of 4.4% at –150°C and shape recovery upon heating. The shape-memory properties are caused by reversible martensitic transformation. This Mg alloy includes lightweight scandium, and its density is about 2 grams per cubic centimeter, which is one-third less than that of practical TiNi SMAs. This finding raises the potential for development and application of lightweight SMAs across a number of industries.

  7. Surfacing of drawplates by compound alloys

    Energy Technology Data Exchange (ETDEWEB)

    Myshko, Y.D.; Gladchenko, A.N.; Gonchak, N.E.; Matkovskii, N.V.; Nechiporenko, V.G.

    1984-01-01

    Hard alloy sleeves fixed by soldering them with silver solder to drawplates of pelletizing heads in machinery used for processing plastic materials does not provide the required strength. A technology for surfacing the drawplates with wear-resistant alloys type VK8+MNMts by thermal impregnation has been developed. The strength of the compound alloy tested depends on the wetting of the solid phase by the matrix alloy-binder. The systems studied possessed high wettability and a stable bond between the phases. Surfaces drawplates have been successfully tested.

  8. Development of a program in LABVIEW platform to controlling and monitoring a Sievert-type system for comminution of metallic uranium and its alloys

    Energy Technology Data Exchange (ETDEWEB)

    Dutra, Aimore R.R.; Ferraz, Wilmar B.; Ferreira, Ricardo A.N., E-mail: ferrazw@cdtn.b, E-mail: ranf@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2011-07-01

    A comminution process by hydriding-dehydriding method was developed at CDTN-Centro de Desenvolvimento da Tecnologia Nuclear with the purpose of obtaining plate type nuclear fuel. This fuel requires the use of metallic uranium and its alloys in form of powders. This comminution process was performed based on a Sievert system. Initially this system was controlled and monitored by a computer program developed in Turbo Pascal language. In order to improve the control of the comminution process, a new program was developed in LabVIEW platform. This paper presents a description of this new program and the main aspects of the operation of the system. The more accurate monitoring and controlling of the various stages of the comminution process as well as greater flexibility in the choice of input data, real-time graphics, generation of reports and a reduction of time passivation were achieved. (author)

  9. Development of a program in LABVIEW platform to controlling and monitoring Sievert-type system for comminution of metallic uranium and its alloys

    Energy Technology Data Exchange (ETDEWEB)

    Dutra, Aimore R.R.; Ferraz, Wilmar B.; Ferreira, Ricardo A.N., E-mail: ferrazw@cdtn.b, E-mail: ranf@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2011-07-01

    A comminution process by hydriding-de hydriding method was developed at CDTN-Centro de Desenvolvimento da Tecnologia Nuclear with the purpose of obtaining plate type nuclear fuel. This fuel requires the use of metallic uranium and its alloys in form of powders. This comminution process was performed based on a Sievert system. Initially this system was controlled and monitored by a computer program developed in Turbo Pascal language. In order to improve the control of the comminution process, a new program was developed in LabVIEW platform. This paper presents a description of this new program and the main aspects of the operation of the system. The more accurate monitoring and controlling of the various stages of the comminution process as well as greater flexibility in the choice of input data, real-time graphics, generation of reports and a reduction of time passivation were achieved. (author)

  10. Lattice parameters values and phase diagram for the Cu2Zn1−zMnzGeSe4 alloy system

    International Nuclear Information System (INIS)

    Highlights: • The samples were annealed at 500 °C for 1 month. • Samples in the ranges 0 < z < 0.375 had the tetragonal stannite α structure (I4¯2m). • For 0.725 < z ⩽ 1 the wurtz–stannite δ structure (Pmn21). • Undercooling effects occur for samples in the range 0.725 < z < 0.925. - Abstract: The T(z) phase diagram of the Cu2Zn1−zMnzGeSe4 alloy system is obtained from X-ray diffraction and differential thermal analysis DTA. At room temperature, the X-ray diffraction data showed that samples in the ranges 0 < z < 0.375 had the tetragonal stannite α structure (I4¯2m), while for 0.725 < z ⩽ 1 the wurtz–stannite δ structure (Pmn21). The α and δ fields are separated by a relative wide three-phase field (α + δ + MnSe2). The DTA thermograms were used to construct the phase diagram of the Cu2Zn1−zMnzGeSe4 alloy system. It was confirmed that the Cu2ZnGeSe4 and Cu2MnGeSe4 compounds melt incongruently. It was observed that undercooling effects occur for samples in the range 0.725 < z < 0.925

  11. Translating VDM to Alloy

    DEFF Research Database (Denmark)

    Lausdahl, Kenneth

    2013-01-01

    specifications. However, to take advantage of the automated analysis of Alloy, the model-oriented VDM specifications must be translated into a constraint-based Alloy specifications. We describe how a sub- set of VDM can be translated into Alloy and how assertions can be expressed in VDM and checked by the Alloy...

  12. New Dental Alloys with Special Consumer Properties

    Institute of Scientific and Technical Information of China (English)

    TYKOCHINSKIY D. S.; VASEKIN V. V.

    2012-01-01

    The purpose of the investigation was to create a new gold alloy of yellow for casting the frames of metal-ceramic dentures.The yellow color corresponds to the consumer and aesthetic needs of some patients,because it is a sign of the metal,which is noble and innocuous.The main alloying elements of the majority of gold alloys for metal-ceramics are platinum and palladium,which increase the strength characteristics.Copper,tin,and other precious metals and base metals are also introduced in these alloys.At the same time,it is necessary to ensure the correspondence of the properties of the alloy with those of the ceramics applied onto the metal frame.For this purpose,the thermal expansion coefficient of the alloy (TEC) should be in a range of 13.5~14.5 × 10-6 K-1 when heated from 20 to 600 ℃.The two-component alloys,alloying of gold with platinum and palladium results in a decrease in the TEC,and the introduction of copper,silver,and tin,increases it.Multidirectional influence of the alloying elements is a factor in achieving compliance of the TEC with the given values of the alloy.In multicomponent systems,however,the mutual influence of individual components on the properties of the alloy is unpredictable.This also applies to the color characteristics of the alloys,which vary in the direction of reducing the yellowness with increasing concentration of platinum and palladium,while other elements may have the opposite effect on the results.Yellowness index (YI),calculated according to the results of spectrophotometric studies,has been chosen as an objective indicator of color.In this study,the requirement for YI was given not less than 25; the color of such alloys can be called light yellow.All the alloys investigated contained 85% (by weight)of gold.Therefore,higher corrosion resistance and biological inertness of a finished dental products were ensured.Among the alloys that met the yellowness/TEC requirements,two alloys have been selected that were "most yellow

  13. Influence of heat treatment and welding on fatigue strength in molybdenum alloys of Mo-Zr-B and Mo-Al-B systems

    International Nuclear Information System (INIS)

    Fatigue test results are presented for thin sheets and welded joints of molybdenum base alloys TsM6 and TsM10. It is shown that the fatigue strength of alloys is greatly dependent on their structural states (deformed, polygonized, recrystallized, cast). Deformed alloys have the highest value of endurance limit, cast and recrystallized alloys posses the least one. The dependence of endurance limit on grain size obeys the power law. Some correlations were established between fatigue resistance and short-term tensile properties of the alloys studied

  14. Rotor-bearing system integrated with shape memory alloy springs for ensuring adaptable dynamics and damping enhancement-Theory and experiment

    Science.gov (United States)

    Enemark, Søren; Santos, Ilmar F.

    2016-05-01

    Helical pseudoelastic shape memory alloy (SMA) springs are integrated into a dynamic system consisting of a rigid rotor supported by passive magnetic bearings. The aim is to determine the utility of SMAs for vibration attenuation via their mechanical hysteresis, and for adaptation of the dynamic behaviour via their temperature dependent stiffness properties. The SMA performance, in terms of vibration attenuation and adaptability, is compared to a benchmark configuration of the system having steel springs instead of SMA springs. A theoretical multidisciplinary approach is used to quantify the weakly nonlinear coupled dynamics of the rotor-bearing system. The nonlinear forces from the thermo-mechanical shape memory alloy springs and from the passive magnetic bearings are coupled to the rotor and bearing housing dynamics. The equations of motion describing rotor tilt and bearing housing lateral motion are solved in the time domain. The SMA behaviour is also described by the complex modulus to form approximative equations of motion, which are solved in the frequency domain using continuation techniques. Transient responses, ramp-ups and steady-state frequency responses of the system are investigated experimentally and numerically. By using the proper SMA temperature, vibration reductions up to around 50 percent can be achieved using SMAs instead of steel. Regarding system adaptability, both the critical speeds, the mode shapes and the modes' sensitivity to disturbances (e.g. imbalance) highly depend on the SMA temperature. Examples show that vibration reduction at constant rotational speeds up to around 75 percent can be achieved by changing the SMA temperature, primarily because of stiffness change, whereas hysteresis only limits large vibrations. The model is able to capture and explain the experimental dynamic behaviour.

  15. Atomic scale modelling of hexagonal structured metallic fission product alloys

    OpenAIRE

    Middleburgh, S. C.; King, D M; Lumpkin, G. R.

    2015-01-01

    Noble metal particles in the Mo-Pd-Rh-Ru-Tc system have been simulated on the atomic scale using density functional theory techniques for the first time. The composition and behaviour of the epsilon phases are consistent with high-entropy alloys (or multi-principal component alloys)—making the epsilon phase the only hexagonally close packed high-entropy alloy currently described. Configurational entropy effects were considered to predict the stability of the alloys with increasing temperature...

  16. Passive control of the flutter instability on a two-degrees-of-freedom system with pseudoelastic shape-memory alloy springs.

    Directory of Open Access Journals (Sweden)

    Malher A.

    2014-01-01

    Full Text Available A passive control of aeroelastic instabilities on a two-degrees-of-freedom (dofs system is considered here using shape memory alloys (SMA springs in their pseudo-elastic regime. SMA present a solid-solid phase change that allow them to face strong deformations (∼ 10%; in the pseudo-elastic regime, an hysteresis loop appears in the stress-strain relationship which in turn gives rise to an important amount of dissipated energy. This property makes the SMA a natural candidate for damping undesired vibrations in a passive manner. A 2-dofs system is here used to model the classical flutter instability of a wing section in an uniform flow. The SMA spring is selected on the pitch mode in order to dissipate energy of the predominant motion. A simple model for the SMA hysteresis loop is introduced, allowing for a quantitative study of the important parameters to optimize in view of an experimental design.

  17. Prediction of corrosion-fatigue initiation in low-alloy steel and carbon-steel/water systems at 288 degrees C

    International Nuclear Information System (INIS)

    There has been recent concern about corrosion fatigue data (produced on initially smooth specimens) for carbon and low alloy steels in high temperature water. The concern hinges around the decrease in cycles to crack 'initiation' observed with specific combinations of temperature, dissolved oxygen content and loading history, such that the cycles to crack initiation may be less than those given by the current ASME III design code; thus, the concern is relevant to life extension decisions for Light Water Reactors, (LWR's). After a brief review of the laboratory data on this subject, this paper concentrates on the development of a life-prediction model for corrosion-fatigue 'initiation' of such parameters as strain rate, corrosion potential, sulfur content, loading history, strain amplitude, etc. It is concluded that, although the ASME III code approach to corrosion fatigue of carbon and low alloy steels does not specifically account for the wide range of system parameters pertinent to LWR operations, the current ASME III code line is probably conservative for normal operating conditions

  18. Liquid structure as a guide for phase stability in the solid state: Discovery of a stable compound in the Au-Si alloy system

    Energy Technology Data Exchange (ETDEWEB)

    Tasci, Emre S. [Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628CD Delft (Netherlands); Sluiter, Marcel H.F., E-mail: m.h.f.sluiter@tudelft.nl [Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628CD Delft (Netherlands); Pasturel, Alain [Laboratoire de Physique et Modelisation des Milieux Condensees, 38042 Grenoble (France); Villars, Pierre [Material Phases Data System (MPDS), CH-6354 Vitznau (Switzerland)

    2010-01-15

    A new crystalline ground state was discovered in the Au-Si system through first-principles electronic structure calculations. The new structure was found using the experimentally and theoretically determined local atomic structure in the liquid as a guide for the solid state. Local atomic structure in the liquid was matched with that for all known crystal structures as compiled in the Pauling File structural database. The best matching crystalline structures were then explicitly calculated using first-principles methods. Most candidate crystal structures were found to be close, but above the enthalpy of a composition weighted average of the face-centered cubic Au and diamond structure Si terminal phases, but one crystal structure was more stable than the terminal phases by about 10 meV atom{sup -1} at T = 0 K. As first-principles simulations of local structure are feasible for most liquid alloys, the present methodology is applicable to other alloys lying near a eutectic composition.

  19. Neutron irradiation effect on thermomechanical properties of shape memory alloys

    International Nuclear Information System (INIS)

    Alloys of Ti-Ni, Ti-Ni-Pd, Fe-Mn-Si, Mn-Cu-Cr, Mn-Cu, Cu-Al-Mn, Cu-Al-Ni systems are investigated after irradiation in IVV-2M reactor at various temperatures with neutron fluence of 1019 - 1020 cm-2. The degradation of shape memory effect in titanium nickelide base alloys is revealed after irradiation. Mn-Cu and Mn-Cu-Cr alloys show the best results. Trends in shape memory alloy behaviour depending on irradiation temperature are found. A consideration is given to the possibility of using these alloys for components of power reactor control and protection systems

  20. Alloyed steel

    International Nuclear Information System (INIS)

    The composition and properties are listed of alloyed steel for use in the manufacture of steam generators, collectors, spacers, emergency tanks, and other components of nuclear power plants. The steel consists of 0.08 to 0.11% w.w. C, 0.6 to 1.4% w.w. Mn, 0.35 to 0.6% w.w. Mo, 0.02 to 0.07% w.w. Al, 0.17 to 0.37% w.w. Si, 1.7 to 2.7% w.w. Ni, 0.03 to 0.07% w.w. V, 0.005 to 0.012% w.w. N, and the rest is Fe. The said steel showed a sufficiently low transition temperature between brittle and tough structures, a greater depth of hardenability, and better weldability than similar steels. (B.S.)

  1. Relations between the modulus of elasticity of binary alloys and their structure

    Science.gov (United States)

    Koster, Werner; Rauscher, Walter

    1951-01-01

    A comprehensive survey of the elastic modulus of binary alloys as a function of the concentration is presented. Alloys that form continuous solid solutions, limited solid solutions, eutectic alloys, and alloys with intermetallic phases are investigated. Systems having the most important structures have been examined to obtain criteria for the relation between lattice structure, type of binding, and elastic behavior.

  2. Ternary alloy systems. Phase diagrams, crystallographic and thermodynamic data critically evaluated by MSIT {sup registered}. Subvol. D. Iron systems. Pt. 4: Selected systems from Cu-Fe-Si to Fe-N-U

    Energy Technology Data Exchange (ETDEWEB)

    Effenberg, Guenter; Ilyenko, Svitlana (eds.) [MSI, Materials Science International Services GmbH, Stuttgart (Germany); Baetzner, Christian; Cacciamani, Gabriele; Cornish, Lesley (and others)

    2008-07-01

    Volume 11 of group IV presents phase diagrams, crystallographic and thermodynamic data of ternary alloy systems. The subvolume D deals with iron systems, with part 4 considering selected systems from Cu-Fe-Si to Fe-N-U. At ambient pressure the equilibria of each individual ternary system are discussed as functions of temperature yielding spatial diagrams whose sections and projections are displayed. The phase equilibria are described in terms of liquidus, solidus and solvus projections, isothermal, vertical and quasibinary sections. Data on invariant equilibria are generally given in the form of tables and reaction schemes. The volume forms a comprehensive review and rigorous systematization of the presently available data. For each system the often conflicting literature and contradictory information has been thoroughly evaluated by a team of experts, MSIT, and can thus be presented in a standard format. Back to the year 1900 the literature has been reviewed, implying possible reinterpretations from today's state of knowledge, and incorporated in the volume. The tables and diagrams are preceded by descriptive commenting texts. (orig.)

  3. Comment on 'Thermodynamic description of the Hg-Te system' [Journal of Alloys and Compounds 494 (1-2) (2010) 102-108

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Youn-Bae, E-mail: ybkang@postech.ac.k [Graduate Institute of Ferrous Technology (GIFT), Pohang University of Science and Technology, Hyojadong, Pohang, Kyungbuk 790-784 (Korea, Republic of)

    2010-09-03

    Recently Gierlotka [Journal of Alloys and Compounds 494 (1-2) (2010) 102-108] reported on thermodynamic assessments of the Hg-Te binary system using (1) two-sublattice ionic model, (2) associate model, and (3) random mixing model for the liquid phase. And a conclusion was made such that the two-sublattice ionic model and the associate model are superior to the random mixing model in describing thermodynamic properties and phase diagram of the Hg-Te system, and the two-sublattice ionic model seems to be more suitable for describing Hg-Te binary system due to ionic behavior of the Hg-Te liquid. Purpose of the present letter is to point out that (1) the two-sublattice ionic model and the associate model can be made mathematically the same in a binary system as in the Hg-Te system, therefore two different assessments using either the two-sublattice ionic model or the associate model by Gierlotka are essentially very similar as long as the parameters used in both models are similar, and (2) the two models can also be made mathematically equivalent even in higher order system under certain conditions.

  4. Shape memory alloys. Ultralow-fatigue shape memory alloy films.

    Science.gov (United States)

    Chluba, Christoph; Ge, Wenwei; Lima de Miranda, Rodrigo; Strobel, Julian; Kienle, Lorenz; Quandt, Eckhard; Wuttig, Manfred

    2015-05-29

    Functional shape memory alloys need to operate reversibly and repeatedly. Quantitative measures of reversibility include the relative volume change of the participating phases and compatibility matrices for twinning. But no similar argument is known for repeatability. This is especially crucial for many future applications, such as artificial heart valves or elastocaloric cooling, in which more than 10 million transformation cycles will be required. We report on the discovery of an ultralow-fatigue shape memory alloy film system based on TiNiCu that allows at least 10 million transformation cycles. We found that these films contain Ti2Cu precipitates embedded in the base alloy that serve as sentinels to ensure complete and reproducible transformation in the course of each memory cycle. PMID:26023135

  5. The (CuGaSe{sub 2}){sub 1-x}(MgSe){sub x} alloy system (0{<=}x{<=}0.5): X-ray diffraction, energy dispersive spectrometry and differential thermal analysis

    Energy Technology Data Exchange (ETDEWEB)

    Grima Gallardo, P.; Munoz, M.; Ruiz, J. [Centro de Estudios en Semiconductores (C.E.S.), Dpto. Fisica, Fac. Ciencias, La Hechicera, Merida (Venezuela); Delgado, G.E. [Laboratorio de Cristalografia, Dpto. Quimica, Fac. Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Briceno, J.M. [Laboratorio de Analisis Quimico y Estructural (LAQUEM), Dpto. Fisica, Fac. Ciencias, La Hechicera, Merida (Venezuela)

    2004-07-01

    The (CuGaSe{sub 2}){sub 1-x}(MgSe){sub x} alloy system (0=}0.15. All the alloys showed the chalcopyrite structure and the lattice parameters of the unit cell do not follow a linear behavior but showed a soft local maximum at x {proportional_to} 0.15. In the single-phase field, the increasing behavior of the lattice parameters can be reproduced using an extension for quaternary alloys of Jaffe and Zunger's model for chalcopyrites. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Surface alloying in the Sn/Ni(111) system studied by synchrotron radiation photoelectron valence band spectroscopy and ab-initio density of states calculations

    Energy Technology Data Exchange (ETDEWEB)

    Karakalos, S.; Ladas, S. [Department of Chemical Engineering, University of Patras and FORTH/ICE-HT, POB 1414, 26504 Rion (Patras) (Greece); Janecek, P.; Sutara, F.; Nehasil, V. [Department of Electronic and Vacuum Physics, Charles University, V.Holesovickach 2, 18000 Prague 8 (Czech Republic); Tsud, N. [Sincrotrone Trieste, Strada Statale 14, km 163.5, 34012 Basovizza-Trieste (Italy); Prince, K. [Sincrotrone Trieste, Strada Statale 14, km 163.5, 34012 Basovizza-Trieste (Italy); INFM, Laboratorio TASC, in Area Science Park, Strada Statale 14, km 163.5, 34012 Basovizza-Trieste (Italy); Matolin, V. [Department of Electronic and Vacuum Physics, Charles University, V.Holesovickach 2, 18000 Prague 8 (Czech Republic); Chab, V. [Institute of Physics, Czech Academy of Sciences, Cucrovarnicka 10, 16200 Prague (Czech Republic); Papanicolaou, N.I. [Department of Physics, University of Ioannina, P.O. Box 1186, 45110 Ioannina (Greece)], E-mail: nikpap@uoi.gr; Dianat, A.; Gross, A. [Institute of Theoretical Chemistry, University of Ulm, D-89069 Ulm (Germany)

    2008-03-31

    Photoelectron spectroscopy using synchrotron radiation and ab-initio electronic structure calculations were used in order to describe the fine structure of the valence band in the Sn/Ni(111) system. The characteristic contributions of each metal in the valence band photoemission spectra obtained with a photon energy of 80 eV and their changes upon the formation of the ({radical}3 x {radical}3)R30{sup o} Sn/Ni(111) surface alloy were also born out in the calculated density-of-states curves in fair agreement with the experiments. The Sn-Ni interaction leads to a considerable broadening of the valence band width at the bimetallic surfaces.

  7. A tunable amorphous p-type ternary oxide system: The highly mismatched alloy of copper tin oxide

    Energy Technology Data Exchange (ETDEWEB)

    Isherwood, Patrick J. M., E-mail: P.J.M.Isherwood@lboro.ac.uk; Walls, John M. [CREST, School of Electronic, Electrical and Systems Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU (United Kingdom); Butler, Keith T.; Walsh, Aron [Centre for Sustainable Technologies and Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom)

    2015-09-14

    The approach of combining two mismatched materials to form an amorphous alloy was used to synthesise ternary oxides of CuO and SnO{sub 2}. These materials were analysed across a range of compositions, and the electronic structure was modelled using density functional theory. In contrast to the gradual reduction in optical band gap, the films show a sharp reduction in both transparency and electrical resistivity with copper contents greater than 50%. Simulations indicate that this change is caused by a transition from a dominant Sn 5s to Cu 3d contribution to the upper valence band. A corresponding decrease in energetic disorder results in increased charge percolation pathways: a “compositional mobility edge.” Contributions from Cu(II) sub band-gap states are responsible for the reduction in optical transparency.

  8. X-ray diffraction study of the ordered structures and phase relation in Pd-Mn alloy system

    International Nuclear Information System (INIS)

    This paper reports the results of structural study on the ordered phases formed in Pd-rich Pd-Mn alloys adopting X-ray powder diffraction method. Formations of the tetragonal D023-type Pd3Mn, orthorhombic Pd2Mn and orthorhombic Pd5Mn3 reported by previous researchers have been confirmed. Rietveld refinement of the diffraction data of the latter two phases has determined precisely the atomic parameters and revealed the significance of the shifts of atoms in Pd2Mn. It is shown that the L10-type phase extends to about 33 at% Mn at high temperatures and Pd2Mn and Pd5Mn3 form via two-step ordering from the L10-type phase. A revised phase diagram on the Pd-rich side has been proposed. Discussion is given on the stability of the relevant ordered phases by making calculation of the total energy by the density functional method. (author)

  9. Quasicrystal-reinforced Mg alloys

    International Nuclear Information System (INIS)

    The formation of the icosahedral phase (I-phase) as a secondary solidification phase in Mg–Zn–Y and Mg–Zn–Al base systems provides useful advantages in designing high performance wrought magnesium alloys. The strengthening in two-phase composites (I-phase + α-Mg) can be explained by dispersion hardening due to the presence of I-phase particles and by the strong bonding property at the I-phase/matrix interface. The presence of an additional secondary solidification phase can further enhance formability and mechanical properties. In Mg–Zn–Y alloys, the co-presence of I and Ca2Mg6Zn3 phases by addition of Ca can significantly enhance formability, while in Mg–Zn–Al alloys, the co-presence of the I-phase and Mg2Sn phase leads to the enhancement of mechanical properties. Dynamic and static recrystallization are significantly accelerated by addition of Ca in Mg–Zn–Y alloy, resulting in much smaller grain size and more random texture. The high strength of Mg–Zn–Al–Sn alloys is attributed to the presence of finely distributed Mg2Sn and I-phase particles embedded in the α-Mg matrix. (review)

  10. Effect of Heat-Treatment Process on Properties of Rare Earth Mg-Based System Hydrogen Storage Alloys with AB3-Type

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The effect of heat-treatment process on the properties of Mm0.8Mg0.2(NiCoAlMn)3.5 hydrogen storage alloy was discussed. The electrochemical properties such as cycling stability, activation property, and the plateau voltage of the alloy which was heat-treated in various temperatures and times had different changes during the cycle process, the optimum heat-treatment conditions of this alloy were determined by this work.

  11. Low-density, refractory multi-principal element alloys of the Cr–Nb–Ti–V–Zr system: Microstructure and phase analysis

    International Nuclear Information System (INIS)

    The crystal structure, microstructure, density and Vickers hardness of four multi-principal element alloys, NbTiVZr, NbTiV2Zr, CrNbTiZr, and CrNbTiVZr, are reported. The characteristics of these potential new high-temperature structural alloys are explored. The alloys were prepared by vacuum arc melting followed by hot isostatic pressing (at 1200 °C, 207 MPa for 1 h) and homogenization annealing (at 1200 °C for 24 h). The alloys have densities of 6.52, 6.34, 6.67 and 6.57 g cm−3, and Vickers microhardness values of 3.29, 2.99, 4.10 and 4.72 GPa, respectively. The NbTiVZr alloy is essentially a single-phase alloy consisting of a coarse-grained disordered body-centered cubic (bcc) phase with fine, submicron-size precipitates inside the grains. The NbTiV2Zr alloy contains three disordered bcc phases. The CrNbTiZr and CrNbTiVZr alloys contain a disordered bcc phase and an ordered Laves phase. The lattice parameters and compositions of the identified phases are reported. The experimental data are compared with the results of the thermodynamic modeling of non-equilibrium and equilibrium phases in these alloys

  12. New amorphous alloy with high glass forming ability on the Cu-Zr-Al-Gd system; Desenvolvimento de nova liga com estrutura amorfa no sistema Cu-Zr-Al-Gd

    Energy Technology Data Exchange (ETDEWEB)

    Mazzer, E.M.; Aliaga, L.C.R.; Bolfarini, C.; Botta Filho, W.J.; Kiminami, C.S., E-mail: eric_mazzer@hotmail.co [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais

    2010-07-01

    The prediction of the Glass Forming Ability (GFA) in metallic alloys is usually performed by empirical or semi-empirical criteria in binary or ternary systems. For multi-component systems with more than three elements, the criteria or models become extremely complex making it impractical. In this paper we present the results on the GFA prediction of the Cu-Zr-Al-Gd alloys, where compositions had been selected for the synergy of the topological instability and electronegativity criteria which was increased by the average radio criterion for the quaternary system. Alloys were prepared and processed by arc-meting and die casting techniques. Characterization was made by x-ray diffraction (XRD), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) techniques. It was concluded that Cu{sub 39,2}Zr{sub 49}Al{sub 9}, {sub 80}Gd{sub 2} alloy presents high thermal stability expressed by great supercooled liquid region upper to 76 deg C. (author)

  13. New Stainless Steel Alloys for Low Temperature Surface Hardening?

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lundin; Dahl, Kristian Vinter; Somers, Marcel A. J.

    2015-01-01

    The present contribution showcases the possibility for developing new surface hardenable stainless steels containing strong nitride/carbide forming elements (SNCFE). Nitriding of the commercial alloys, austenitic A286, and ferritic AISI 409 illustrates the beneficial effect of having SNCFE present...... in the stainless steel alloys. The presented computational approach for alloy design enables “screening” of hundreds of thousands hypothetical alloy systems by use of Thermo-Calc. Promising compositions for new stainless steel alloys can be selected based on imposed criteria, i.e. facilitating easy...

  14. Molybdenum-rhenium alloy development for space nuclear power applications

    International Nuclear Information System (INIS)

    Refractory metals and refractory metal alloys are essential to the development of advanced nuclear reactor systems for space power applications because of the anticipated high operating temperatures of these systems. The refractory metals and alloys based on niobium, molybdenum, tantalum and tungsten are being considered for use in these systems because of their high temperature capabilities and compatibility with alkali metals. Molybdenum-base alloys offer many advantages in these systems, but their brittleness at low temperatures serves as a major deterrent to their use. Molybdenum-rhenium alloys with 11-13 wt% rhenium have been found to possess good low temperature ductility that results from the solution softening process in this alloy system. The development of solution softened molybdenum-rhenium alloys for use in space nuclear power applications is in progress at the Los Alamos National Laboratory, and this paper presents a review and update of this work

  15. Alloy Fabrication Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — At NETL’s Alloy Fabrication Facility in Albany, OR, researchers conduct DOE research projects to produce new alloys suited to a variety of applications, from gas...

  16. Oxidation of alloys for advanced steam turbines

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, Gordon R.; Covino, Bernard S., Jr.; Bullard, Sophie J.; Ziomek-Moroz, M.; Alman, David E.

    2005-01-01

    Ultra supercritical (USC) power plants offer the promise of higher efficiencies and lower emissions. Current goals of the U.S. Department of Energy’s Advanced Power Systems Initiatives include coal generation at 60% efficiency, which would require steam temperatures of up to 760°C. This research examines the steamside oxidation of advanced alloys for use in USC systems, with emphasis placed on alloys for high- and intermediate-pressure turbine sections.

  17. Oxidation of advanced steam turbine alloys

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, G.R.; Covino, B.S., Jr.; Bullard, S.J.; Ziomek-Moroz, M.

    2006-03-01

    Advanced or ultra supercritical (USC) steam power plants offer the promise of higher efficiencies and lower emissions. Current goals of the U.S. Department of Energy’s Advanced Power Systems Initiatives include coal generation at 60% efficiency, which would require steam temperatures of up to 760°C. This research examines the steamside oxidation of advanced alloys for use in USC systems, with emphasis placed on alloys for high- and intermediate-pressure turbine sections.

  18. Microstructural characterisation of Ti-Nb-(Fe-Cr) alloys obtained by powder metallurgy

    OpenAIRE

    Amigó Mata, Angèlica; Zambrano, Jenny Cecilia; Martínez, S; Amigó Borrás, Vicente

    2014-01-01

    beta alloys based on the Ti Nb alloy system are of growing interest to the biomaterial community. The addition of small amounts of Fe and Cr further increases beta-phase stability, improving the properties of Ti Nb alloy. However, PM materials sintered from elemental powders are inhomogeneous due to restricted solid state diffusion and mechanical alloying provides a route to enhance mixing and lemental diffusion. The microstructural characteristics and bend strength of Ti Nb (Fe Cr) alloys ...

  19. The Microstructure-Processing-Property Relationships in an Al Matrix Composite System Reinforced by Al-Cu-Fe Alloy Particles

    Energy Technology Data Exchange (ETDEWEB)

    Fei Tang

    2004-12-19

    Metal matrix composites (MMC), especially Al matrix composites, received a lot of attention during many years of research because of their promise for the development of automotive and aerospace materials with improved properties and performance, such as lighter weight and better structural properties, improved thermal conductivity and wear resistance. In order to make the MMC materials more viable in various applications, current research efforts on the MMCs should continue to focus on two important aspects, including improving the properties of MMCs and finding more economical techniques to produce MMCs. Solid state vacuum sintering was studied in tap densified Al powder and in hot quasi-isostatically forged samples composed of commercial inert gas atomized or high purity Al powder, generated by a gas atomization reaction synthesis (GARS) technique. The GARS process results in spherical Al powder with a far thinner surface oxide. The overall results indicated the enhanced ability of GARS-processed Al and Al alloy powders for solid state sintering, which may lead to simplification of current Al powder consolidation processing methods. Elemental Al-based composites reinforced with spherical Al-Cu-Fe alloy powders were produced by quasi-isostatic forging and vacuum hot pressing (VHP) consolidation methods. Microstructures and tensile properties of AYAl-Cu-Fe composites were characterized. It was proved that spherical Al-Cu-Fe alloy powders can serve as an effective reinforcement particulate for elemental Al-based composites, because of their high hardness and a preferred type of matrix/reinforcement interfacial bonding, with reduced strain concentration around the particles. Ultimate tensile strength and yield strength of the composites were increased over the corresponding Al matrix values, far beyond typical observations. This remarkable strengthening was achieved without precipitation hardening and without severe strain hardening during consolidation because of

  20. Characterization of crystallite size, dislocation characteristics and stacking faults in nanostructured mechanically alloyed Cu–Fe system using an advanced X-ray diffraction analysis method

    International Nuclear Information System (INIS)

    Highlights: • Various microstructural features of mechanically alloyed Cu–Fe are investigated simultaneously. • The crystallite size and size distribution are calculated via refinement of XRD profiles. • Using the eCMWP method, characteristics of dislocations are studied as a function of milling time and composition. • The probability of stacking faults are calculated. -- Abstract: Developments in the synthesis of nanostructured materials have expanded the need for appropriate characterization methods. The aim of this work is to apply new X-ray diffraction analysis methods for simultaneous investigation of various microstructural characteristics. For this purpose, the structure of mechanically alloyed Cu–Fe system with three compositions of 30 wt%, 50% and 70% of iron was studied. By applying the modified Williamson-Hall method, the type of dislocations in the FCC phase is distinguished. Afterwards by modification of previous XRD analysis methods, the proportion of edge/screw dislocations was characterized. Moreover, the outer cut-off radius, the density and energy of dislocations were calculated as a function of the composition and the milling time. On the other hand, using the extended convolutional multiple whole profile fitting procedure, the variations in the crystallite size and size distribution of FCC and BCC phases were studied. Finally, the stacking fault probability was calculated in different milled samples. It is revealed that smaller steady state crystallite size of samples with higher Fe content, is relevant to reduction of the outer cut-off radius of dislocation. On the other hand, the density of dislocations and stacking faults increased continuously up to 96 h of milling

  1. Terbium base alloy

    International Nuclear Information System (INIS)

    Composition of terbium-5-7 % gadolinium alloy with high magnetostriction sensitivity (180x10-8 Oe) is suggested. The alloy is designed for usage under cryogenic temperature within 500-1500 Oe fields. Magnetostriction sensitivity of the suggested alloy is by 2-2.5 times higher, than that of well-known before one. 1 tab

  2. F-Alloy: An Alloy Based Model Transformation Language

    OpenAIRE

    Gammaitoni, Loïc; Kelsen, Pierre

    2015-01-01

    Model transformations are one of the core artifacts of a model-driven engineering approach. The relational logic language Alloy has been used in the past to verify properties of model transformations. In this paper we introduce the concept of functional Alloy modules. In essence a functional Alloy module can be viewed as an Alloy module representing a model transformation. We describe a sublanguage of Alloy called F-Alloy that allows the specification of functional Alloy modules. Module...

  3. Effects of annealing on the corrosion and creep resistance of Zr-Nb- Mo or P alloys

    International Nuclear Information System (INIS)

    They have reported that the fabrication processes including especially the different annealing treatments have a significant effect on corrosion and creep resistance of Zr-Nb alloys. So many researchers have studied to establish the ideal alloying elements and their amounts. In this study, two kinds of alloys were designed to improve corrosion and creep resistances. One is Zr-Nb .P alloy; P system (P-1∼4), the other is Zr-Nb-Mo alloys; Mo system (Mo-1∼3). The purpose of this investigation is to get the more effective alloying system and annealing temperature which has good corrosion and creep resistance. The effects of the alloying elements and annealing conditions for the Zr-Nb alloys with P or Mo were investigated. The corrosion resistance of P system alloys were worse than that of Mo system alloys. Because Mo system alloys contain more precipitates that causes more improving corrosion resistance than P system alloys. In the same alloying system, as the heat treatment temperature increased, the corrosion resistance were improved. The creep resistances of P system alloys was better than that of Mo system alloys

  4. Aluminum Bronze Alloys to Improve the System Life of Basic Oxygen and Electric Arc Furnace Hoods, Roofs and Side Vents.

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence C. Boyd Jr.; Dr. Vinod K. Sikka

    2006-12-29

    Energy Industries of Ohio was the lead organization for a consortium that examined the current situation involving the service life of electric arc and basic oxygen furnace hoods, roofs and side vents. Republic Engineered Products (REP), one of the project partners, installed a full-scale Al-Bronze “skirt” in their BOF at their Lorain OH facility, believed to be the first such installation of this alloy in this service. In 24 months of operation, the Al-Bronze skirt has processed a total of 4,563 heats, requiring only 2 shutdowns for maintenance, both related to physical damage to the skirt from operational mishaps. Yearly energy savings related to the REP facility are projected to be ~ 10 billion Btu's with significant additional environmental and productivity benefits. In recognition of the excellent results, this project was selected as the winner of the Ohio’s 2006 Governor’s Award for Excellence in Energy, the state’s award for outstanding achievements in energy efficiency.

  5. Alloy phase stability and design

    International Nuclear Information System (INIS)

    At the level of basic quantum theory the papers in this symposium reflect the great progress that has been made in understanding the physical properties of both ordered and disordered alloys based on Density Functional Theory (DFT). DFT provides a quantitative parameter-free (often referred to as first principles) theory of the ground state properties of these systems. This general approach has also been used in combination with classical elasticity and dislocation theory to provide the first quantitative understanding of some of the mechanical properties of intermetallic alloys. Recent advances have built on DFT theory to provide the first glimpses of a theory of the finite temperature phase stability of alloys. It is the strength of these first principles theories that the understanding of materials properties is in terms of the underlying electronic structure. At the level of atomistic simulation, based on semi-empirical potentials, again much progress has been made in understanding the properties of extended defects such as grain boundaries and dislocations. On the experimental front increasingly sophisticated tools are being brought to bear in order to understand both the underlying electronic structure and detailed atomic arrangements. This information, together with input from theory, is playing an increasing role in guiding alloy design efforts. At the more practical level a number of these sophisticated alloy design efforts have in recent years produced impressive results across a broad front. The properties of existing materials are continually being improved and new ones developed. Often this progress is based on a deeper understanding of the properties at the atomistic and electronic level. The design of new ordered intermetallic alloys that have reached or are reaching commercialization represents one of the major achievements of this investment of intellectual resources

  6. Pilot Study for Investigating the Cyclic Behavior of Slit Damper Systems with Recentering Shape Memory Alloy (SMA Bending Bars Used for Seismic Restrainers

    Directory of Open Access Journals (Sweden)

    Junwon Seo

    2015-07-01

    Full Text Available Although the steel slit dampers commonly utilized for aseismic design approach can dissipate considerable energy created by the yielding of base materials, large residual deformation may happen in the entire frame structure. After strong external excitation, repair costs will be incurred in restoring a structure to its original condition and to replace broken components. For this reason, alternative recentering devices characterized by smart structures, which mitigate the damage for such steel energy dissipation slit dampers, are developed in this study. These devices, feasibly functioning as seismic restrainers, can be improved by implementing superelastic shape memory alloy (SMA bending bars in a parallel motion with the steel energy-dissipating damper. The bending bars fabricated with superelastic SMAs provide self-centering forces upon unloading, and accordingly contribute to reducing permanent deformation in the integrated slit damper system. The steel slit dampers combined with the superelastic SMA bending bars are evaluated with respect to inelastic behavior as simulated by refined finite element (FE analyses. The FE slit damper models subjected to cyclic loads are calibrated to existing test results in an effort to predict behavior accurately. The responses of the proposed slit damper systems are compared to those of the conventionally used slit damper systems. From the analysis results, it is concluded that innovative steel slit dampers combined with superelastic SMA bending bars generate remarkable performance improvements in terms of post-yield strength, energy dissipation, and recentering capability.

  7. Multiharmonic rf feedforward system for compensation of beam loading and periodic transient effects in magnetic-alloy cavities of a proton synchrotron

    Science.gov (United States)

    Tamura, Fumihiko; Ohmori, Chihiro; Yamamoto, Masanobu; Yoshii, Masahito; Schnase, Alexander; Nomura, Masahiro; Toda, Makoto; Shimada, Taihei; Hasegawa, Katsushi; Hara, Keigo

    2013-05-01

    Beam loading compensation is a key for acceleration of a high intensity proton beam in the main ring (MR) of the Japan Proton Accelerator Research Complex (J-PARC). Magnetic alloy loaded rf cavities with a Q value of 22 are used to achieve high accelerating voltages without a tuning bias loop. The cavity is driven by a single harmonic (h=9) rf signal while the cavity frequency response also covers the neighbor harmonics (h=8,10). Therefore the wake voltage induced by the high intensity beam consists of the three harmonics, h=8,9,10. The beam loading of neighbor harmonics is the source of periodic transient effects and a possible source of coupled bunch instabilities. In the article, we analyze the wake voltage induced by the high intensity beam. We employ the rf feedforward method to compensate the beam loading of these three harmonics (h=8,9,10). The full-digital multiharmonic feedforward system was developed for the MR. We describe the system architecture and the commissioning methodology of the feedforward patterns. The commissioning of the feedforward system has been performed by using high intensity beams with 1.0×1014 proteins per pulse. The impedance seen by the beam is successfully reduced and the longitudinal oscillations due to the beam loading are reduced. By the beam loading compensation, stable high power beam operation is achieved. We also report the reduction of the momentum loss during the debunching process for the slow extraction by the feedforward.

  8. Fiber reinforced titanium alloy composites

    International Nuclear Information System (INIS)

    The more important titanium matrix composites studied to date are composed of titanium alloy matrices, such as Ti 6Al--4V, reinforced with filaments of boron, silicon carbide, or sapphire, as well as with wires of beryllium or refractory metal alloys. The primary fabrication techniques for these materials involve vacuum hot pressing at 1300 to 16000F, alternate layers of titanium alloy matrix foils, and suitably aligned filament mats. The more ductile reinforcements such as beryllium, have been incorporated into titanium matrix composites by coextrusion. Fabrication of composite gas turbine engine fan blades from both boron (SiC coated) and beryllium reinforced Ti 6Al--4V alloy is described. Feasibility studies have been made in the fabrication of Boron/Ti 6Al--4V composite rings for possible gas turbine engine disc applications. Mechanical properties of various titanium matrix composite systems are presented and demonstrate the attractive elevated temperature properties of some systems to 10000F. (35 fig, 6 tables) (U.S.)

  9. Surface tension of tin-lithium alloys

    International Nuclear Information System (INIS)

    Temperature and concentration dependences of surface tension of tin-lithium alloys in the range of temperatures 250-410 deg C and concentrations 6.3-15.0 at. % Li were measured by the big drop method. It was ascertained that lithium is a surfactant component of Sn-Li system. Positive sign of surface tension temperature coefficients suggests prevailing lithium desorption from the liquid alloy surface with temperature increase. Calculated value of maximum lithium adsorption in its alloys with tin, containing about 4 at. % Li, makes up 8.5 x 10-6 mol/m2

  10. 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.)

  11. Dislocation Formation in Alloys

    Science.gov (United States)

    Minami, Akihiko; Onuki, Akira

    2006-05-01

    An interaction between dislocations and phase transitions is studied by a phase field model both in two and three dimensional systems. Our theory is a simple extension of the traditional linear elastic theory, and the elastic energy is a periodic function of local strains which is reflecting the periodicity of crystals. We find that the dislocations are spontaneously formed by quenching. Dislocations are formed from the interface of binary alloys, and slips are preferentially gliding into the soft metals. In three dimensional systems, formation of dislocations under applied strain is studied in two phase state. We find that the dislocation loops are created from the surface of hard metals. We also studied the phase separation above the coexisting temperature which is called as the Cottrell atmosphere. Clouds of metals cannot catch up with the motion of dislocations at highly strained state.

  12. Titanium-alloy enhances bone-pedicle screw fixation: mechanical and histomorphometrical results of titanium-alloy versus stainless steel

    OpenAIRE

    Christensen, F.B.; Dalstra, M.; Sejling, F.; Overgaard, S.; Bünger, C.

    2000-01-01

    Several types of pedicle screw systems have been utilized to augment lumbar spine fusion. The majority of these systems are made of stainless steel (Ss), but titanium-alloy (Ti-alloy) devices have recently been available on the market. Ti-alloy implants have several potential advantages over Ss ones. High bioactivity and more flexibility may improve bone ingrowth and mechanical fixation, and the material also offers superior magnetic resonance imaging (MRI) and computed tomography (CT) resolu...

  13. The Al-rich region of the Al-Mn-Ni alloy system. Part II. Phase equilibria at 620-1000 oC

    International Nuclear Information System (INIS)

    Research highlights: → Phase equilibria in the Al-rich region of the Al-Mn-Ni alloy system were studied at 1000, 950, 850, 750, 700, 645 and 620 deg. C by means of SEM, TEM, powder XRD and DTA. → Three ternary thermodynamically stable intermetallics, the φ-phase (Al5Co2-type, hP26, P63/mmc; a = 0.76632(16), c = 0.78296(15) nm), the κ-phase (κ-Al14.4Cr3.4Nil.1-type, hP227, P63/m; a = 1.7625(10), c = 1.2516(10) nm), and the O-phase (O-Al77Cr14Pd9-type, Pmmn, oP650,: a = 2.3316(16), b = 1.2424(15), c = 3.2648(14) nm), as well as three ternary metastable phases, the decagonal D3-phase with periodicity about 1.25 nm, the Al9(Mn,Ni)2-phase (Al9Co2-type, P1121/a, mP22; a = 0.8585(16), b = 0.6269(9), c = 0.6205(11) nm, β = 95.34(10)o) and the O1-phase (basecentered orthorhombic, a ∼ 23.8, b ∼ 12.4, c ∼ 32.2 nm) were revealed. → The existence of a thermodynamically stable R-phase of stoichiometry Al60Mn11Ni4, reported earlier in literature, was not confirmed in the present study. - Abstract: Phase equilibria in the Al-rich region of the Al-Mn-Ni alloy system were studied at 1000, 950, 850, 750, 700, 645 and 620 oC. Three ternary thermodynamically stable intermetallics, the φ-phase (Al5Co2-type, hP26, P63/mmc; a = 0.76632(16), c = 0.78296(15) nm), the κ-phase (κ-Al14.4Cr3.4Nil.1-type, hP227, P63/m; a = 1.7625(10), c = 1.2516(10) nm), and the O-phase (O-Al77Cr14Pd9-type, Pmmn, oP650,: a = 2.3316(16), b = 1.2424(15), c = 3.2648(14) nm), as well as three ternary metastable phases, the decagonal D3-phase with periodicity about 1.25 nm, the Al9(Mn,Ni)2-phase (Al9Co2-type, P1121/a, mP22; a = 0.8585(16), b = 0.6269(9), c = 0.6205(11) nm, β = 95.34(10)o) and the O1-phase (base-centered orthorhombic, a ∼ 23.8, b ∼ 12.4, c ∼ 32.2 nm) were revealed. Their physicochemical behaviour in the Al-Mn-Ni alloy system was studied.

  14. Coupling between bulk ordering and surface segregation: from alloy surfaces to surface alloys

    International Nuclear Information System (INIS)

    -The knowledge of the alloy surfaces is of prime interest to understand their catalytic properties. On the one hand, the determination of the stability of the surface alloys depends very strongly on the behaviours of the AcB1-c alloy surfaces. On the other hand, the knowledge of the kinetics of the formation-dissolution of surface alloys can allow to understand the equilibrium segregation isotherm. We have then studied the relation between the equilibrium surface segregation in an alloy AcB1-c and the kinetics of dissolution of a few metallic layers of A/B and the inverse deposit. We have used an energetic model derived from the electronic structure (T.I.B.M.) allowing us to study the surface segregation both in the disordered state and in the ordered one. The kinetics of dissolution were studied using the kinetic version of this model (K.T.I.B.M.) consistent with the equilibrium model. To illustrate our study, we have chosen the Cu-Pd system, a model for the formation of surface alloys and for which a great number of studies, both experimental and theoretical, are in progress. We then have shown for the (111) surface of this system that the surface alloys obtained during the dissolution are related to the alloy surfaces observed for the equilibrium segregation. The Cu-Pd system is characteristic of systems which have a weak segregation energy. Then, we have performed an equivalent study for a system with a strong segregation energy. Our choice was directly put on the Pt-Sn system. The surface behaviour, both in equilibrium and during the kinetics of dissolution, is very different from the Cu-Pd case. In particular, we have found pure 2-D surface alloys. Finally, a quenched molecular dynamics study has allowed us to determine the relative stability of various possible surface superstructures. (author)

  15. Thermodynamical study of the vanadium-hydrogen system. The hydrogen effect on the mechanical properties of V-4Cr-4Ti and V-5Cr-5Ti alloys

    International Nuclear Information System (INIS)

    In the framework of the international research programs on fusion reactors, the vanadium alloys are among the most appropriate candidate to constitute the first wall. The author deals with the specific alloys V-4Cr-4Ti and V-5Cr-5Ti and study the hydrogen diffusion. Experimental results show that the induced hydrogen concentration in the sample by diffusion is higher, for the same partial pressure of exposure, in the case of the alloy than for the pure vanadium. He shows that this result can be explained by the trapping for which the hydrogen is trapped by the titanium. (A.L.B.)

  16. The Al-rich region of the Al-Mn-Ni alloy system. Part I: Ternary phases at 750-950 oC

    International Nuclear Information System (INIS)

    Research highlights: → The Al-Mn-Ni alloy system was investigated by means of SEM, TEM, powder XRD and DTA in the Al-rich region ranging from 60 to 100 at.% Al in the temperature range from 750 to 950 deg. C. → Two new ternary intermetallic compounds were revealed: the φ-phase (Al5Co2-type, hP26, P63/mmc: a = 0.76632(16) and c = 0.78296(15) nm) and the κ-phase (κ-Al14.4Cr3.4Nil.1-type, hP227, P63/m: a = 1.7625(10) and c = 1.2516(10) nm). The formation of the O-phase (Pmmn; oP650; O-Al77Cr14Pd9-type; a = 2.3316(16), b = 1.2424(15) and c = 3.2648(14) nm) was confirmed and its chemical composition as well as thermodynamic stability was specified. → Close relationship between the hexagonal phases φ, κ and μ as well as the orthorhombic phases T, R and O has been discussed. - Abstract: Ternary phases in the Al-rich region of the Al-Mn-Ni alloy system were studied at 950, 850 and 750 deg. C. Two new ternary intermetallic compounds were revealed: the φ-phase (Al5Co2-type, hP26, P63/mmc: a = 0.76632(16) and c = 0.78296(15) nm) and the κ-phase (κ-Al14.4Cr3.4Nil.1-type, hP227, P63/m: a = 1.7625(10) and c = 1.2516(10) nm). The formation of the O-phase (Pmmn; oP650; O-Al77Cr14Pd9-type; a = 2.3316(16), b = 1.2424(15) and c = 3.2648(14) nm) was confirmed and its chemical composition as well as thermodynamic stability was specified.

  17. The DynAlloy Visualizer

    OpenAIRE

    Bendersky, Pablo; Galeotti, Juan Pablo; Garbervetsky, Diego

    2014-01-01

    We present an extension to the DynAlloy tool to navigate DynAlloy counterexamples: the DynAlloy Visualizer. The user interface mimics the functionality of a programming language debugger. Without this tool, a DynAlloy user is forced to deal with the internals of the Alloy intermediate representation in order to debug a flaw in her model.

  18. Electrical resistivity of liquid noble metal alloys

    International Nuclear Information System (INIS)

    Calculations of the dependence of the electrical resistivity in liquid Ag-Au, Cu-Ag, Cu-Au binary alloys on composition are reported. The structure of the binary alloy is described as a hard sphere system. A one-parameter local pseudopotential, which incorporates s-d hybridization effects phenomenologically, is employed in the resistivity calculation. A reasonable agreement with experimental trends is observed in cases where experimental information is available. (author)

  19. Introduction to hydrogen in alloys

    International Nuclear Information System (INIS)

    Substitutional alloys, both those that form hydrides and those that do not, are discussed, but with more emphasis on the former than the latter. This overview includes the following closely related subjects: (1) the significant effects of substitutional solutes on the pressure-composition-temperature (PCT) equilibria of metal-hydrogen systems, (2) the changes in thermodynamic properties resulting from differences in atom size and from modifications of electronic structure, (3) attractive and repulsive interactions between H and solute atoms and the effects of such interactions on the pressure dependent solubility for H, (4) H trapping in alloys of Group V metals and its effect on the terminal solubility for H (TSH), (5) some other mechanisms invoked to explain the enhancement (due to alloying) of the (TSH) in Group V metals, and (6) H-impurity complexes in alloys of the metals Ni, Co, and Fe. Some results showing that an enhanced TSH may ameliorate the resistance of a metal to hydrogen embrittlement are presented

  20. Introduction to hydrogen in alloys

    Energy Technology Data Exchange (ETDEWEB)

    Westlake, D.G.

    1980-01-01

    Substitutional alloys, both those that form hydrides and those that do not, are discussed, but with more emphasis on the former than the latter. This overview includes the following closely related subjects: (1) the significant effects of substitutional solutes on the pressure-composition-temperature (PCT) equilibria of metal-hydrogen systems, (2) the changes in thermodynamic properties resulting from differences in atom size and from modifications of electronic structure, (3) attractive and repulsive interactions between H and solute atoms and the effects of such interactions on the pressure dependent solubility for H, (4) H trapping in alloys of Group V metals and its effect on the terminal solubility for H (TSH), (5) some other mechanisms invoked to explain the enhancement (due to alloying) of the (TSH) in Group V metals, and (6) H-impurity complexes in alloys of the metals Ni, Co, and Fe. Some results showing that an enhanced TSH may ameliorate the resistance of a metal to hydrogen embrittlement are presented.

  1. Response to letter "Electron correlation and relativity of the 5f electrons in the Usbnd Zr alloy system"

    Science.gov (United States)

    Xie, Wei; Marianetti, Chris A.; Morgan, Dane

    2016-08-01

    In the Letter [Söderlind et al., J. Nucl. Mater. 444, 356 (2014)], Söderlind et al. state their interpretation that 1) we view electron correlation to be strong and including spin-orbit coupling (SOC) to be necessary for U metal and Usbnd Zr alloy in our article [Xiong et al., J. Nucl. Mater. 443, 331 (2013)]. Further, they argue that 2) density functional theory (DFT) without adding the Hubbard U potential, especially when solved using all electron methods, already models U and Usbnd Zr accurately, and 3) adding the Hubbard U potential to DFT in DFT + U models U and Usbnd Zr worse than DFT according to volume, bulk modulus, and magnetic moments predicted from their calculations of the γU phase of elemental U metal. With respect to Söderlind et al.'s interpretation 1), we clarify that our opinions are that U and Usbnd Zr are not strongly, but weakly to moderately correlated and that including SOC is beneficial but not necessary for modeling most ground state properties of U and Usbnd Zr. With respect to Söderlind et al.'s argument 2) we demonstrate that previously neglected and very recent experimental data suggest that DFT in Söderlind's full-potential linear muffin-tin orbital calculations [Söderlind, Phys. Rev. B 66, 085113 (2002)] in fact models the bulk modulus and elastic constants of αU with errors considerably larger than other related elements, e.g., most transition metals. With respect to Söderlind et al.'s argument 3) we argue that they have inappropriately focused on just one phase (the BCC γU phase of U metal), neglecting the other phases which represent the majority of our evidence, and made overgeneralizations based on results at only one Ueff value of 2 eV. We therefore maintain our original conclusion that the accuracy of DFT for modeling U and Usbnd Zr has room for improvement and DFT + U can be of value for this purpose on at least some ground state properties.

  2. Controlling quality of ferroalloys and alloying additives in the manufacture of nickel alloys for nuclear applications

    International Nuclear Information System (INIS)

    Nickel alloys supplied to the nuclear industry must meet strict requirements for quality and traceability of constituents. Ensuring that end products meet those requirements involves careful control of the raw materials used in melting the alloys. Especially important is an effective system of quality control for purchasing and consuming ferroalloys and alloying additives. Development and operation of such a system requires (1) adequate specifications, (2) good relations with suppliers, (3) an approved-suppliers list, (4) formal receiving inspection, and (5) backup surveillance during processing

  3. A study on new zirconium alloys with improved corrosion resistance

    International Nuclear Information System (INIS)

    In order to improve the corrosion resistance of zirconium alloys, corrosion mechanism of zirconium alloys has been systematically studied. By acquiring mastery of different existing theories, the new frame of theory system was established. And based on existing test results, seven new zirconium alloys were designed. For different alloy systems, different representative manufacturing processes were designed. And autoclave corrosion tests validated author's design theory. Finally, two new zirconium alloys were obtained which had improved corrosion resistance. The specimens were corroded in pure water and lithiated water at 360°C/18.6 MPa after 200 days exposure, two zirconium alloys with copper and silicon additions were better than other five zirconium alloys. And for the zirconium alloys with Nb content (0.8∼1.2) %, conventional low temperature annealing process should be used, which is beneficial to the corrosion resistance improvement. For the zirconium alloy with Nb content (0.2∼0.5) %, β water quenching process instead of intermediate annealing should be used, which can obviously improve the corrosion resistance of zirconium alloys. (author)

  4. Advanced gas cooled nuclear reactor materials evaluation and development program. Selection of candidate alloys. Vol. 1. Advanced gas cooled reactor systems definition

    International Nuclear Information System (INIS)

    Candidate alloys for a Very High Temperature Reactor (VHTR) Nuclear Process Heal (NPH) and Direct Cycle Helium Turbine (DCHT) applications in terms of the effect of the primary coolant exposure and thermal exposure were evaluated

  5. Advanced gas cooled nuclear reactor materials evaluation and development program. Selection of candidate alloys. Vol. 1. Advanced gas cooled reactor systems definition

    Energy Technology Data Exchange (ETDEWEB)

    Marvin, M.D.

    1978-10-31

    Candidate alloys for a Very High Temperature Reactor (VHTR) Nuclear Process Heal (NPH) and Direct Cycle Helium Turbine (DCHT) applications in terms of the effect of the primary coolant exposure and thermal exposure were evaluated. (FS)

  6. Electrochemical deposition of La-Mg alloys in LaCl3-MgCl2-KCl system with molten salt electrolysis process

    Directory of Open Access Journals (Sweden)

    Sahoo Kumar D.

    2014-01-01

    Full Text Available La-Mg alloys of different compositions were prepared by electrolysis of LaCl3-MgCl2-KCl melts. Different phases of La-Mg alloys were characterized by X-ray diffraction (XRD and Scanning Electron Microscopy (SEM. Energy dispersive spectrometry (EDS and Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES analyses showed that chemical compositions of La-Mg alloys were consistent with phase structures of XRD pattern, and magnesium content in the alloy could be controlled by electrolysis parameters. The effects of various process parameters such as concentration of magnesium chloride in the bath, temperature of electrolysis and cathode current density on the current efficiency have been investigated. A maximum current efficiency of 85% and yield of 80% was obtained from the bath at 12.5A/cm2 current density at an operating temp 850°C.

  7. Bounded Model Checking of Temporal Formulas with Alloy

    OpenAIRE

    Cunha, Alcino

    2012-01-01

    Alloy is formal modeling language based on first-order relational logic, with no specific support for specifying reactive systems. We propose the usage of temporal logic to specify such systems, and show how bounded model checking can be performed with the Alloy Analyzer.

  8. Design and fabrication of a mechanical alloying system for preparing intermetallic, nanocrystalline, amorphous and quasicrystalline compounds; Diseno y fabricacion de un sistema de aleado mecanico para preparar compuestos intermetalicos, nanocristalinos, amorfos y cuasicristalinos

    Energy Technology Data Exchange (ETDEWEB)

    Bonifacio M, J.; Iturbe G, J.L.; Castaneda J, G. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2002-07-01

    In this work a grinding system was designed and fabricated which allowed to improve the operation conditions in time, frequency, temperature and selection of the grinding media and that allow the contamination decrease of the compounds. By means of this method of mechanical alloying new metallic compounds can be produced, starting from elemental powders, with fine and controlled microstructures. These compounds prepared by this method are going to be used as materials for the hydrogen storage. (Author)

  9. Antibacterial biodegradable Mg-Ag alloys

    Directory of Open Access Journals (Sweden)

    D Tie

    2013-06-01

    Full Text Available The use of magnesium alloys as degradable metals for biomedical applications is a topic of ongoing research and the demand for multifunctional materials is increasing. Hence, binary Mg-Ag alloys were designed as implant materials to combine the favourable properties of magnesium with the well-known antibacterial property of silver. In this study, three Mg-Ag alloys, Mg2Ag, Mg4Ag and Mg6Ag that contain 1.87 %, 3.82 % and 6.00 % silver by weight, respectively, were cast and processed with solution (T4 and aging (T6 heat treatment.The metallurgical analysis and phase identification showed that all alloys contained Mg4Ag as the dominant β phase. After heat treatment, the mechanical properties of all Mg-Ag alloys were significantly improved and the corrosion rate was also significantly reduced, due to presence of silver. Mg(OH2 and MgO present the main magnesium corrosion products, while AgCl was found as the corresponding primary silver corrosion product. Immersion tests, under cell culture conditions, demonstrated that the silver content did not significantly shift the pH and magnesium ion release. In vitro tests, with both primary osteoblasts and cell lines (MG63, RAW 264.7, revealed that Mg-Ag alloys show negligible cytotoxicity and sound cytocompatibility. Antibacterial assays, performed in a dynamic bioreactor system, proved that the alloys reduce the viability of two common pathogenic bacteria, Staphylococcus aureus (DSMZ 20231 and Staphylococcus epidermidis (DSMZ 3269, and the results showed that the killing rate of the alloys against tested bacteria exceeded 90%. In summary, biodegradable Mg-Ag alloys are cytocompatible materials with adjustable mechanical and corrosion properties and show promising antibacterial activity, which indicates their potential as antibacterial biodegradable implant materials.

  10. Benchmarking of thermal hydraulic loop models for Lead-Alloy Cooled Advanced Nuclear Energy System (LACANES), phase-I: Isothermal steady state forced convection

    International Nuclear Information System (INIS)

    As highly promising coolant for new generation nuclear reactors, liquid Lead-Bismuth Eutectic has been extensively worldwide investigated. With high expectation about this advanced coolant, a multi-national systematic study on LBE was proposed in 2007, which covers benchmarking of thermal hydraulic prediction models for Lead-Alloy Cooled Advanced Nuclear Energy System (LACANES). This international collaboration has been organized by OECD/NEA, and nine organizations - ENEA, ERSE, GIDROPRESS, IAEA, IPPE, KIT/IKET, KIT/INR, NUTRECK, and RRC KI - contribute their efforts to LACANES benchmarking. To produce experimental data for LACANES benchmarking, thermal-hydraulic tests were conducted by using a 12-m tall LBE integral test facility, named as Heavy Eutectic liquid metal loop for integral test of Operability and Safety of PEACER (HELIOS) which has been constructed in 2005 at the Seoul National University in the Republic of Korea. LACANES benchmark campaigns consist of a forced convection (phase-I) and a natural circulation (phase-II). In the forced convection case, the predictions of pressure losses based on handbook correlations and that obtained by Computational Fluid Dynamics code simulation were compared with the measured data for various components of the HELIOS test facility. Based on comparative analyses of the predictions and the measured data, recommendations for the prediction methods of a pressure loss in LACANES were obtained. In this paper, results for the forced convection case (phase-I) of LACANES benchmarking are described.

  11. Effect of high temperature corrosion tests in be-liquid Li-V4Ti4Cr alloy system on mechanical properties of beryllium

    International Nuclear Information System (INIS)

    Full text of publication follows: Self-cooled lithium blanket is one of the promising concepts of breeding blanket for future fusion reactor. Beryllium proposed to be used in this design of blanket as a neutron multiplier and moderator for providing the required tritium breeding efficiency. Corrosion behavior of beryllium in liquid Li is important and at the same time not clearly understood aspect of beryllium application in fusion. Recent experimental results on beryllium corrosion behavior of two modem RF beryllium grades (DIP, TE-56) after testing in Be- liquid lithium - V4Ti4Cr alloy static system for 200-500 hours at temperatures from 600 to 800 deg. C are presented. The influences of test conditions (temperature, duration, lithium purity), beryllium characteristics (microstructure, grain size and chemical composition) and penetration of lithium into beryllium on compressive properties of beryllium are discussed. Compressive properties can be considered as an integral characteristic of grain boundaries weakening that is caused by penetration of lithium into beryllium during corrosion tests. The data obtained show that the stability of modem beryllium grades in lithium is much higher than that for the 'old' grades. (authors)

  12. Study on the cutting of self-fluxing alloy of Ni-Cr-WC systems. Ni-Cr-WC kei jiyo gokin yosha himaku no sessaku kako ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Inui, Y.; Hayami, T.; Kubohori, T.; Ikuta, T. (Kinki University, Osaka (Japan). Faculty of Science and Technology)

    1991-03-31

    In this paper, to investigate the cutting of sprayed self-fluxing alloy films of Ni-Cr-WC system containing 35 and 50%WC-Co composite grains in the Ni-Cr matrix, cutting tests by the lathe turning method were performed using CBN tools containing either oxide or carbonitride systems as a binder. Self-fluxing alloy films with about 2mm thichness, which were sprayed on the surface of a cylindrical substrate made of low carbon steel, were used as cutting materials. The wear was increased rapidly at the early stage of cutting, but this was changed to the gradual increasing level after about 30 seconds of cutting. The tool was subject to the abrasive action in cutting, and was fractured when CBN content was low. The CBN tool containing oxide system was found most suitable for cutting of these alloys. The variation in resistance to cutting was observed at the early stage, but this was disappeared after 90 seconds. The roughness of the cutting surface was decreased with cutting time. 8 refs., 10 figs., 2 tabs.

  13. Measurement of super alloy and tool steel powder consolidation using an eddy current sensor based intelligent processing system

    Energy Technology Data Exchange (ETDEWEB)

    Rowland, R.; Deng, Y.G. [MATSYS, Arlington, VA (United States); Dorsch, C.; Verducci, J. [Crucible Research, Pittsburgh, PA (United States)

    1996-12-31

    An eddy current sensor based intelligent processing system designed to monitor consolidation powdered metal compacts has been implemented at Crucible Research, Inc. In this work an eddy current sensor measurement system was used to track the consolidation of nickel-based superalloy and tool steel powders. The system enabled the HIP process engineer to interactively control pressure and temperature profile while observing the real-time density rate. The primary features of this system are automated in-HIP sensor calibration, sensor thermal compensation, reproducible density measurement and computer data acquisition for real-time graphical display, process control, and recording for post process analysis and process model optimization. This work has demonstrated that the application of an intelligent system for HIPing provides the process engineer with a tool for rapid process improvement.

  14. Superplasticity in titanium alloys

    OpenAIRE

    J. Sieniawski; Motyka, M.

    2007-01-01

    Purpose: The paper reports characteristic of superplasticity phenomenon in titanium alloys and possibility of its applications.Design/methodology/approach: The main objective of the paper is to show features of superplastic forming of titanium alloys and current research trends aiming at widespread application of this technology.Findings: In the paper characteristic of selected superplastic titanium alloys was presented. The effect of microstructural parameters on superplasticity was consider...

  15. Phase transformations in high alloy cold work tool steel

    OpenAIRE

    Šturm, Roman; Moravčík, Roman; Štefániková, Mária; Čička, Roman; Čaplovič, L'ubomír; Kocúrová, Karin

    2015-01-01

    Phase transformations in the alloy tool steels have a crucial effect on the final properties of the steels. High alloy systems have different solidification conditions compared to construction steels. This paper deals with the phase evolution in high alloy tool steel in quasi-equilibrium state. For analysis various methods such as differential thermal analysis, thermomagnetometry, light microscopy, scanning electron microscopy with energy dispersive analysis, X-ray diffraction analysis and di...

  16. Phase transformations in high alloy cold work tool steel:

    OpenAIRE

    Čaplovič, L'.; Čička, Roman; Kocúrová, Karin; Moravčík, Roman; Štefániková, Mária; Šturm, Roman

    2012-01-01

    Phase transformations in the alloy tool steels have a crucial effect on the final properties of the steels. High alloy systems have different solidification conditions compared to construction steels. This paper deals with the phase evolution in high alloy tool steel in quasi-equilibrium state. For analysis various methods such as differential thermal analysis, thermomagnetometry, light microscopy, scanning electron microscopy with energy dispersive analysis, X-ray diffraction analysis and di...

  17. Processing and production of molybdenum and tungsten alloys

    International Nuclear Information System (INIS)

    The technological means to produce and process Mo and W alloys are summarized because for many Mo and W alloy systems the mechanical properties can be optimized only by thermomechanical processing requiring production and processing capabilities that are not widely available. First, the producers of commercial Mo and W alloys are presented along with currently available product forms. Second, currently disclosed standard capabilities of producers and processors in the United States are presented. 56 references, 13 figures, 9 tables

  18. Environmental Studies on Titanium Aluminide Alloys

    Science.gov (United States)

    Brindley, William J.; Bartolotta, Paul A.; Smialek, James L.; Brady, Michael P.

    2005-01-01

    Titanium aluminides are attractive alternatives to superalloys in moderate temperature applications (600 to 850 C) by virtue of their high strength-to-density ratio (high specific strength). These alloys are also more ductile than competing intermetallic systems. However, most Ti-based alloys tend to degrade through interstitial embrittlement and rapid oxidation during exposure to elevated temperatures. Therefore, their environmental behavior must be thoroughly investigated before they can be developed further. The goals of titanium aluminide environmental studies at the NASA Lewis Research Center are twofold: characterize the degradation mechanisms for advanced structural alloys and determine what means are available to minimize degradation. The studies to date have covered the alpha 2 (Ti3Al), orthorhombic (Ti2AlNb), and gamma (TiAl) classes of alloys.

  19. Ternary alloy nanocatalysts for hydrogen evolution reaction

    Indian Academy of Sciences (India)

    SOUMEN SAHA; SONALIKA VAIDYA; KANDALAM V RAMANUJACHARY; SAMUEL E LOFLAND; ASHOK K GANGULI

    2016-04-01

    Cu–Fe–Ni ternary alloys (size ∼55–80 nm) with varying compositions viz. CuFeNi (A1), CuFe2Ni (A2) and CuFeNi2 (A3) were successfully synthesized using microemulsion. It is to be noted that synthesis of nanocrystallineternary alloys with precise composition is a big challenge which can be overcome by choosing an appropriate microemulsion system. High electrocatalytic activity towards HER in alkaline medium was achieved by the formation of alloys of metals with low and high binding energies. A high value of current density (228 mA cm$^2$) at an overpotential of 545 mV was obtained for CuFeNi (A1), which is significantly high as compared to the previously reported Ni$_{59}$Cu$_{41}$ alloy catalyst.

  20. Simulation of nuclei morphologies for binary alloy

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    We study the critical nuclei morphologies of a binary alloy by the string method. The dynamic equation of the string, connecting the metastable phase (liquid) and stable phase (solid), is governed by Helmholtz free energy for the binary alloy system at a given temperature. The stationary string through the critical nucleus (saddle point) is obtained if the relaxation time of the string is su?ciently large. The critical nucleus radius and energy barrier to nucleation of a pure alloy with isotropic interface energy in two and three dimensions are calculated, which are consistent with the classical nucleation theory. The critical nuclei morphologies are sensitive to the anisotropy strength of interface energy and interface thickness of alloy in two and three dimensions. The critical nucleus and energy barrier to nucleation become smaller if the anisotropy strength of the interface energy is increased, which means that it is much easier to form a stable nucleus if the anisotropy of the interface energy is considered.

  1. Corrosion resistant amorphous alloys

    International Nuclear Information System (INIS)

    A review of publication data on corrosion resistance of amorphous alloys and the methods of amorphization of surface layers of massive materials (laser treatment, iron implantation, detonation-gas spraying, cathode and ion sputtering, electrodeposition) was made. A study was made on corrosion properties of Fe66Cr11B10Si4 alloy in cast state and after laser irradiation, rendering the surface amorphous as well as the samples of Arenco iron and steel 20 with ion-plasma coatings of Fe-Cr-Ni-Ti alloy. It was established that amorphous coatings posses much higher corrosion resistance as compared to crystalline alloys on the same base

  2. Effect of alloy composition on the volume fraction of beta phase in duplex titanium alloys

    International Nuclear Information System (INIS)

    Titanium alloys are strong, light, corrosion resistant and superplastic. While many of them show superplastic behavior, working and forging temperatures are still high, 850-925 degree C, and their range is narrow. Moreover, the material's resistance to deformation is not negligible and, therefore, the cost of making dies and presses for forging or hot deformation is high and it poses a serious problem. To increase the efficiency and to reduce the temperature of hot deformation, increasing the volume fraction of the beta phase present in duplex titanium alloys is suggested. With the introduction of the beta-modified Ti-6Al-4V alloy the decrease in the temperature and the increase in the strain rate of the superplastic regime promise to make superplastic forming of this alloy even more economical, and many researches have been made. In this study, efforts are put on designing new duplex alloys based on the Ti-6Al-4V and Ti-Al-Fe systems, which will have a beta volume fraction of 40-50 percent at around 800 degree C. To accomplish this, experimental volume fractions of the beta phase in several titanium alloys are being compared with predicted and calculated ones using phase equilibria analyses and some suggestions will be made on modifying the alloy compositions. For comparison, the quaternary Ti-V-Fe-Al system and their subsystems are chosen due to availability of both experimental and thermodynamic data

  3. Effect of titanium addition on fracture toughness behavior of ZL108 alloy

    Institute of Scientific and Technical Information of China (English)

    WENG Yong-gang; LI Zi-jing; LIU Zhi-yong; LIU Wen-cai; WANG Ming-xing; SONG Tian-fu

    2006-01-01

    Two different titanium alloying methods were applied to ZL108 alloy for preparing specimens containing titanium. The specimens were tested on the MTS 810 material test system for studying their behavior of the plane strain fracture toughness KIC. The experimental data were analyzed by the statistical significance tests. The results show that the fracture toughness of the ZL108 alloy containing titanium is superior to that of common ZL108 alloy containing no titanium, but there is no significant difference for different titanium alloying methods. Therefore titanium addition is an effective method for improving the fracture toughness of the alloy ZL108.

  4. Micro X-ray diffraction using X-ray area detector and identifying multiple phases in Zr2TiAl alloy system

    International Nuclear Information System (INIS)

    The birth of X-ray diffraction technique and its evolution has catalyzed the development of solid state science and further our understanding of material properties. The first single crystal X-ray diffraction pattern recorded was of Copper Sulphate Hydrate on a photographic film by Laue, and his co-workers Friedrich and Knipping, in 1912, for which he was awarded the Nobel prize. The actual diffraction pattern obtained was pretty awful with vague smudges instead of sharp diffraction spots (1). Development of X-ray detection technology has been playing an important role in advancing the development of new X-ray diffraction and imaging techniques. For instance, developments in electronics in the 1960's to 80's enabled advent of point detectors (eg. Nal scintillation detector) and line detectors (e.g gas filled single wire detector). These led to faster and more sensitive detection of X-rays leading to good XRD patterns. However, important information about microstructural details, defects, etc that are manifest well in the two dimensional map of the reciprocal space could be obtained reliably using area detectors (e.g X-ray films) (2). In the 1990's new developments in 2D X-ray area detectors such as Charge coupled devices (CCD), Imaging Plate Systems (IPS) and Multiwire proportional counters (MPC) led to replacement of the slower and low sensitive X-ray films with extremely sensitive 2D detection technology. This presentation will discuss these 2D detection techniques and their underlying mechanism. Recently the structure of multiple phases in Zr2TiAl alloy system could be identified using micro-XRD and 2D detection technique. Result of this study will be presented. (author)

  5. Dual-bath Plating of Composition Modulated Alloys (CMA) based on a newly developed Computer Controlled Plating System

    DEFF Research Database (Denmark)

    Tang, Peter Torben; Leisner, Peter; Møller, Per; Nielsen, C. Bergenstof; NabiRahni, D.M.A.

    1994-01-01

    computer controlled plating system for producing large scale CMA-coatings. Employing a dual-bath technique, multilayered materials with more than 1000 alternating layers have been manufactured and investigated. The thickness of each layer ranges from 25 nm to several microns. The characterisation results...

  6. Ultra high strength beta titanium alloy for fasteners

    International Nuclear Information System (INIS)

    A new high strength titanium alloy has been developed primarily intended for fastener applications. While Ti-6Al-4V is used extensively as a fastener alloy in the aerospace industry, its shear strength allowable is limited to 655 MPa (95 ksi). For higher shear strength requirements, various steels or nickel-based alloys are used (up to 860 MPa (125 ksi)), but with the attendant density penalty. This new alloy is intended to provide the 860 MPa shear strength at roughly a 40% weight savings. After screening various alloy systems, the optimum chemistry has been selected as follows: Ti-6.0V-6.2Mo-5.7Fe-3Al. In light of its 125 ksi shear strength goal, the alloy has been designated TIMETAL reg-sign 125

  7. Thermofluency in zirconium alloys

    International Nuclear Information System (INIS)

    A summary is presented about the theoretical and experimental results obtained at present in thermofluency under radiation in zirconium alloys. The phenomenon of thermofluency is presented in a general form, underlining the thermofluency at high temperature because this phenomenon is similar to the thermofluency under radiation, which ocurrs in zirconium alloys into the operating reactor. (author)

  8. Development of Advanced Alloys using Fullerenes

    Science.gov (United States)

    Sims, J.; Wasz, M.; O'Brien, J.; Callahan, D. L.; Barrera, E. V.

    1994-01-01

    Development of advanced alloys using fullerenes is currently underway to produce materials for use in the extravehicular mobility unit (EMU). These materials will be directed toward commercial usages as they are continually developed. Fullerenes (of which the most common is C(sub 60)) are lightweight, nanometer size, hollow molecules of carbon which can be dispersed in conventional alloy systems to enhance strength and reduce weight. In this research, fullerene interaction with aluminum is investigated and a fullerene-reinforced aluminum alloy is being developed for possible use on the EMU. The samples were manufactured using standard commercial approaches including powder metallurgy and casting. Alloys have been processed having 1.3, 4.0 and 8.0 volume fractions of fullerenes. It has been observed that fullerene dispersion is related to the processing approach and that they are stable for the processing conditions used in this research. Emphasis will be given to differential thermal analysis and wavelength dispersive analysis of the processed alloys. These two techniques are particularly useful in determining the condition of the fullerenes during and after processing. Some discussion will be given as to electrical properties of fullerene-reinforced materials. Although the aluminum and other advanced alloys with fullerenes are being developed for NASA and the EMU, the properties of these materials will be of interest for commercial applications where specific Dual-Use will be given.

  9. Crystallization of amorphous Zr-Be alloys

    Science.gov (United States)

    Golovkova, E. A.; Surkov, A. V.; Syrykh, G. F.

    2015-02-01

    The thermal stability and structure of binary amorphous Zr100 - x Be x alloys have been studied using differential scanning calorimetry and neutron diffraction over a wide concentration range (30 ≤ x ≤ 65). The amorphous alloys have been prepared by rapid quenching from melt. The studied amorphous system involves the composition range around the eutectic composition with boundary phases α-Zr and ZrBe2. It has been found that the crystallization of alloys with low beryllium contents ("hypoeutectic" alloys with x ≤ 40) proceeds in two stages. Neutron diffraction has demonstrated that, at the first stage, α-Zr crystallizes and the remaining amorphous phase is enriched to the eutectic composition; at the second stage, the alloy crystallizes in the α-Zr and ZrBe2 phases. At higher beryllium contents ("hypereutectic" alloys), one phase transition of the amorphous phase to a mixture of the α-Zr and ZrBe2 phases has been observed. The concentration dependences of the crystallization temperature and activation energy have been revealed.

  10. Ultrahigh temperature intermetallic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Brady, M.P.; Zhu, J.H.; Liu, C.T.; Tortorelli, P.F.; Wright, J.L.; Carmichael, C.A.; Walker, L.R. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

    1997-12-01

    A new family of Cr-Cr{sub 2}X based alloys with fabricability, mechanical properties, and oxidation resistance superior to previously developed Cr-Cr{sub 2}Nb and Cr-Cr{sub 2}Zr based alloys has been identified. The new alloys can be arc-melted/cast without cracking, and exhibit excellent room temperature and high-temperature tensile strengths. Preliminary evaluation of oxidation behavior at 1100 C in air indicates that the new Cr-Cr{sub 2}X based alloys form an adherent chromia-based scale. Under similar conditions, Cr-Cr{sub 2}Nb and Cr-Cr{sub 2}Zr based alloys suffer from extensive scale spallation.

  11. Manufacturing development of low activation vanadium alloys

    International Nuclear Information System (INIS)

    General Atomics is developing manufacturing methods for vanadium alloys as part of a program to encourage the development of low activation alloys for fusion use. The culmination of the program is the fabrication and installation of a vanadium alloy structure in the DIII-D tokamak as part of the Radiative Divertor modification. Water-cooled vanadium alloy components will comprise a portion of the new upper divertor structure. The first step, procuring the material for this program has been completed. The largest heat of vanadium alloy made to date, 1200 kg of V-4Cr-4Ti, has been produced and is being converted into various product forms. Results of many tests on the material during the manufacturing process are reported. Research into potential fabrication methods has been and continues to be performed along with the assessment of manufacturing processes particularly in the area of joining. Joining of vanadium alloys has been identified as the most critical fabrication issue for their use in the Radiative Divertor Program. Joining processes under evaluation include resistance seam, electrodischarge (stud), friction and electron beam welding. Results of welding tests are reported. Metallography and mechanical tests are used to evaluate the weld samples. The need for a protective atmosphere during different welding processes is also being determined. General Atomics has also designed, manufactured, and will be testing a helium-cooled, high heat flux component to assess the use of helium cooled vanadium alloy components for advanced tokamak systems. The component is made from vanadium alloy tubing, machined to enhance the heat transfer characteristics, and joined to end flanges to allow connection to the helium supply. Results are reported

  12. Brazing with plated alloys

    International Nuclear Information System (INIS)

    The use of braze alloy preforms on complex geometry components is at times a very difficult task requiring extensive handling of the parts or even tack welding of the preform to ensure that it is held in place. One method of overcoming these difficulties is the use of plated braze alloys (i.e., filler metals) applied directly to the braze region. Plating helps to avoid the potential for contamination resulting from handling and also ensures that the braze alloy is located properly. Examples are discussed in which an electroplated silver-copper alloy is used as an alternative to the BAg8 preforms and electroless nickel is used as a replacement for an amorphous Ni-P braze alloy foil. A toroidal cooling plate with helical flow channels was fabricated from oxygen-free high conductivity (OFHC) and brazed using the electroplated silver-copper alloy. The silver-copper braze alloy was applied to the copper substrate in a laminated fashion of alternating layers of silver and copper, which in combination approximated the eutectic composition (72% Ag-28% Cu by weight). Examination of the brazed assemblies indicated that in both cases the advantages of using plated braze alloys are numerous. These advantages include decreased labor, improved cleanliness and exactness of braze alloy placement. The primary disadvantage was an increased tendency for solidification defects presumably resulting from contaminants in the plating baths. This last observation is presently being examined in greater detail. The end results is that the assemblies brazed with the plated alloys were acceptable for the intended application and that the use of plating facilitated the successful assembly of these components

  13. Development of surface composite based on Mg–Al–Ni system on AZ31 magnesium alloy and evaluation of formation mechanism

    International Nuclear Information System (INIS)

    Highlights: • This research showed that by applying friction stir processing (FSP) in-situ surface composite based on Mg–Al/Ni alloying systems is produced on AZ31 plate under different FSP passes. • Thermodynamic and kinetic study of interfacial solid state reactions confirmed phase formation during different FSP passes. • Moreover, the effective Gibbs free energy of formation graphs for the compounds were plotted at 711 K. • Based on kinetic standpoint, schematic diagram of Mg–Ni intermetallic compounds during difference FSP passes is plotted. • Due to presence of intermetallic phases the mean hardness of the stir zone reached about 106 Hv, which is about two times higher than the base metal. - Abstract: The in-situ synthesis of Mg–Al–Ni composite on the surface of AZ31 plate by friction stir processing (FSP), has been investigated in this article. The unprocessed AZ31 plate consisted of grains of 25 μm size. By increasing the number of FSP passes from one to five, the grain size of the AZ31 plate decreased to 7.5 and 3 μm, respectively. A uniform distribution of the reinforcements was also obtained by increasing the number of FSP passes. Based on the results of X-ray diffraction (XRD) and Energy dispersive spectrometry (EDS) analyses, Mg2Ni and Al3Ni2 intermetallic compounds are in-situ formed by a single-pass FSP of the composite specimens. By increasing the number of FSP passes, the amounts of Mg2Ni and Al3Ni2 compounds are dramatically reduced and AlNi and MgNi2 intermetallic compounds take their place. Thermodynamic and kinetic of interfacial solid state reactions were studied to determine the reactive mechanisms and phase evolutions during different passes of FSP. The maximum amount of hardness (∼106 Hv), was obtained for the composite sample after five passes of FSP

  14. Preparation and magnetic properties of InTe-Cr2Te3 alloys In-Cr-Te system

    International Nuclear Information System (INIS)

    Samples of different compositions of the In-Cr-Te system over cross section InTe-Cr2Te3 were synthesized. Their temperature dependences on specific magnetization are studied and the Curie points were determined. Data of the differential thermal, X-ray phase and microstructural analyses on formation of compounds of compositions In9Cr2Te12 and In2Cr6Te11 is a ferromagnetic material, while In2Cr6Te11 features a more complicated magnetic structure

  15. Change of relative Gibbs energy of martensite and austenite alloys of Fe-Ni system in the pre-martensite temperature range

    International Nuclear Information System (INIS)

    Chemical potentials of the components of quenched Fe-Ni alloys (28.7-32.7 at. % Ni) with martensite and austenite structures have been found with the Touch Instant Electromotive Force method. Differences between Gibbs energies of martensite and austenite phases have been calculated in the temperature range of 253-315 K which characterize the relative thermodynamic stability of these metastable phases. By means of interpolation the temperatures were determined when Gibbs energies of alloys with both types of structures are the same. Non-chemical contribution into Gibbs energy of martensite transformation has been evaluated

  16. Application of shape memory alloy (SMA) as actuator

    OpenAIRE

    Ľ. Miková; Medvecká - Beňová, S.; M. Kelemen; Trebuňa, F.; Virgala, I.

    2015-01-01

    This paper deals w ith actuators based on shape memory alloys. The testing device has been developed for experimental verification of shape memory alloy actuator testing. Static characteristic shows the hysteresis of this material. Also dynamic properties have been explored through the step response characteristic. Application of the material as actuator in engineering system is shown.

  17. 铝合金砂型低压铸造浇注系统的选择与设计%Choice and Design of Gating System of Sand Mold Low-pressure Casting for Aluminum Alloy

    Institute of Scientific and Technical Information of China (English)

    佘瑞平; 赵拴勃; 千斌; 段昭; 曲媛

    2013-01-01

    低压铸造是目前获得优质铝合金铸件的有力手段之一.本文立足于低压铸造生产实践经验,结合低压铸造原理,对不同结构、材质(糊状凝固或顺序凝固模式)类型的铝合金铸件砂型低压铸造浇注系统的选择与设计进行了系统的归纳和总结.实践证明,所归纳总结的结果对铝合金低压铸造工艺设计具有一定参考作用.%The low-pressure foundry is one of the emollient means for acquiring a high-quality aluminum alloy castings currently. Based on fulfillment experience of casting production at die low pressure and combining low pressure casting principle. The choice and design of the aluminum alloy castings with different structures, and different material (paste form solidify or in proper order solidify mode) structure and sand type for the low-pressure foundry system were summaried. The research results have singificant effects on the design of aluminum alloy low-pressure casting process

  18. Development of environmentally friendly cast alloys. High-zinc Al alloys

    Directory of Open Access Journals (Sweden)

    W.K. Krajewski

    2010-10-01

    Full Text Available Purpose: The main purpose of this paper is presenting the results obtained in years 2007 – 2010 in frame of the project Marie Curie Transfer of Knowledge – CastModel. The project was focused, among others, at elaborating new, environmentally friendly cast alloys based on the Al-Zn system. Particularly, efforts were aimed at improving ductility of the sand cast high-zinc aluminium alloys (HZnAl by using the newly elaborated master alloys, based on the Al-Zn-Ti system.Design/methodology/approach: The presented work is focused on the nucleation of the high-zinc Al-20 wt% Zn (HZnAl AlZn20 alloy, known as the high damping one, aiming at improving plastic properties of the sand castings. The melted alloy was nucleated with AlTi5B1 (TiBAl and AlTi3C0.15 (TiCAl refiners as well as with the newly introduced ZnAl-Ti3 one. During the research the following experimental techniques were used: LM, SEM-EBSD, EDS, TA, DSC, Quantitative Metallography, UTS, Elongation and Attenuation coefficient measurements.Findings: During the performed examinations it was found out that significant increasing of the grain population of the inoculated alloy increases plasticity represented by elongation. The attenuation coefficient of the nucleated alloy, measured using an Olympus Epoch XT device, preserves its high value. The results obtained allow to characterize the examined AlZn20 alloy as promissive, having good strength and damping properties as well as the environmentally friendly alloy because of its comparatively low melting temperatures.Practical implications: The grain-refined high-zinc aluminium alloys can be used as the high damping substitutes of the traditional, more energy consumable Fe-based foundry alloys.Originality/value: The newly elaborated ZnAl-Ti based master alloys show high refining potency and quick dissolution in low melting temperatures of about 500°C, and are the promissive alternatives of the traditional AlTi-based ones.

  19. An universal formula for the calculation of nitrogen solubility in liquid nitrogen-alloyed steels

    Directory of Open Access Journals (Sweden)

    J. Siwka

    2009-01-01

    Full Text Available The results of the authors’ own experimental studies on the Fe - N system, its standard state, binary alloys of iron with chromium, molybdenum, manganese, nickel, vanadium, silicon and carbon, as well as ternary alloys with chromium, have made it possible to work out the whole required complex of parameters of nitrogen interaction in liquid iron alloys, including the self-interaction parameters of nitrogen-nitrogen and nitrogen-alloying elements.

  20. An universal formula for the calculation of nitrogen solubility in liquid nitrogen-alloyed steels

    OpenAIRE

    J. Siwka; A. Hutny

    2009-01-01

    The results of the authors’ own experimental studies on the Fe - N system, its standard state, binary alloys of iron with chromium, molybdenum, manganese, nickel, vanadium, silicon and carbon, as well as ternary alloys with chromium, have made it possible to work out the whole required complex of parameters of nitrogen interaction in liquid iron alloys, including the self-interaction parameters of nitrogen-nitrogen and nitrogen-alloying elements.

  1. Densities of Some Low Melting Plutonium Alloys

    International Nuclear Information System (INIS)

    The change in fuel density with temperature is an important parameter in nuclear reactor design. For molten fuels, such as are used in LAMPRE-type reactor it is also necessary to know the volume change on melting. A volumeter employing NaK as a working fluid was used to obtain'these data for various plutonium and cerium base alloys over the range 25-800°C. Cerium and several low-melting binary cerium alloys were studied with this equipment. Cerium, Ce-Co, Ce-Ni, and Ce-Cu alloys all exhibit an increase in density on melting, while a Ce-Mn alloy expands on melting. The melting temperatures of several of these alloys differ from those reported in the literature, and the compositions of several eutectics in these systems are also reported incorrectly. The densities of unstabilized and gallium- stabilized plutonium and Pu-10 at.% Fe were measured and compared over this temperature range. All these materials expand on freezing. At 675°C, molten unstabilized plutonium is approximately 2% more dense than Pu-l wt.% Ga alloy. Molten Pu-Fe alloy containing 0.2 wt.% Ga at 435°C is 0.8% less dense than unstabilized alloy. This indicates that there is short-range ordering of plutonium atoms by gallium in the liquid state. The materials containing gallium melted over a 20°C temperature range, while the unstabilized materials melted sharply. Pu-Co-Ce alloys containing 3, 5, 6.2 and 8 g Pu/cm3 were investigated. They all melt in the range 425-442°C and expand on freezing. This expansion increases with increasing plutonium content from 1.3% for the 3 g Pu/cm3 alloy to 3% for the 8 g Pu/cm3 material. Manganese additions to this fuel system are being studied in an attempt to reduce this expansion on freezing. (author)

  2. Alloy NASA-HR-1

    Science.gov (United States)

    Chen, Po-Shou; Mitchell, Michael

    2005-01-01

    NASA-HR-1 is a high-strength Fe-Ni-base superalloy that resists high-pressure hydrogen environment embrittlement (HEE), oxidation, and corrosion. Originally derived from JBK-75, NASA-HR-1 has exceptional HEE resistance that can be attributed to its gamma-matrix and eta-free (Ni3Ti) grain boundaries. The chemistry was formulated using a design approach capable of accounting for the simultaneous effects of several alloy additions. This approach included: (1) Systematically modifying gamma-matrix compositions based on JBK-75; (2) Increasing gamma (Ni3(Al,Ti)) volume fraction and adding gamma-matrix strengthening elements to obtain higher strength; and (3) Obtaining precipitate-free grain boundaries. The most outstanding attribute of NASA-HR-1 is its ability to resist HEE while showing much improved strength. NASA-HR-1 has approximately 25% higher yield strength than JXK-75 and exhibits tensile elongation of more than 20% with no ductility loss in a hydrogen environment at 5 ksi, an achievement unparalleled by any other commercially available alloy. Its Cr and Ni contents provide exceptional resistance to environments that promote oxidation and corrosion. Microstructural stability was maintained by improved solid solubility of the gamma-matrix, along with the addition of alloying elements to retard eta (Ni3Ti) precipitation. NASA-HR-1 represents a new system that greatly extends the compositional ranges of existing HEE-resistant Fe-Ni-base superalloys.

  3. Oxidation mechanisms for alloys in single-oxidant gases

    Energy Technology Data Exchange (ETDEWEB)

    Whittle, D.P.

    1981-03-01

    Scales formed on alloys invariably contain the alloy constituents in a ratio different from that in the alloy, owing to the differing thermodynamic tendencies of the alloy components to react with the oxidant and to differences in diffusion rates in scale and alloy phases. This complex interrelationship between transport rates and the thermodynamics of the alloy-oxidant system can be analyzed using multicomponent diffusion theory when transport-controlled growth of single or multi-layered scales occurs. In particular, the superimposition of the diffusion data on an isothermal section of the appropriate phase diagram indicates the likely morphologies of the reaction products, including the sequence of phases found in the scale, the occurrence of internal oxidation and the development of an irregular metal/scale interface. The scale morphologies on alloys are also time-dependent: there is an initial transient stage, a steady state period, and a final breakdown, the latter often related to mechanical influences such as scale adherence, spallation, thermal or mechanical stresses and void formation. Mechanical influences have a more devastating effect in alloy oxidation due to the changes in alloy surface composition during the steady state period.

  4. Surface alloying in the Sn/Ni(111) system studied by synchrotron radiation photoelectron valence band spectroscopy and ab-initio density of states calculations

    Czech Academy of Sciences Publication Activity Database

    Karakalos, S.; Ladas, S.; Janeček, P.; Šutara, F.; Nehasil, V.; Tsud, N.; Prince, K.; Matolín, V.; Cháb, Vladimír; Papanicolaou, N.I.; Dianat, A.; Gross, A.

    2008-01-01

    Roč. 516, č. 10 (2008), s. 2962-2965. ISSN 0040-6090 Institutional research plan: CEZ:AV0Z10100521 Keywords : surface alloys * electronic structure calculations * photoelectron spectroscopy * synchrotron radiation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.884, year: 2008

  5. Structure, castability and mechanical properties of commercially pure and alloyed titanium cast in graphite mould.

    Science.gov (United States)

    Cheng, W W; Ju, C P; Lin, J H Chern

    2007-07-01

    This report is a study of structure, castability, mechanical properties as well as corrosion behaviour of titanium doped with up to 5 weight percentage (wt%) of a series of alloy elements, including Ta, Mo, Nb, Hf, Zr, Sn, Bi and Ag. The results indicate that, with addition of 1 wt% alloy element, Bi and Mo were most effective in enhancing the castability of titanium. With more alloy elements added, the castability values of most alloys more or less decreased. Except Ti-Mo system, all Ti alloys with a fine acicular morphology had the same crystal structure (hcp) as that of c.p. Ti with a typical lath type morphology. When 3 wt% or more Mo was added, a finer orthorhombic alpha'' phase was formed. The microhardness and bending strength values of Ti alloys were all higher than those of c.p. Ti. Among all alloys, Ti-Mo system exhibited the highest hardness and strength level. For a certain alloy, the bending strength did not necessarily increase with its alloy content. Except Ti-5Zr and Ti-Mo alloys, the bending moduli of most alloy systems were not much different from that of c.p. Ti. All alloys showed an excellent resistance to corrosion in Hanks' solution at 37 degrees C. PMID:17559621

  6. Critical behavior and magnetocaloric effect in Co{sub 50−x}Ni{sub x}Cr{sub 25}Al{sub 25} (x = 0 and 5) full Heusler alloy system

    Energy Technology Data Exchange (ETDEWEB)

    Panda, J.; Saha, S.N.; Nath, T.K., E-mail: tnath@phy.iitkgp.ernet.in

    2015-09-25

    Highlights: • The Curie temperature of alloy series of Co{sub 50−x}Ni{sub x}Cr{sub 25}Al{sub 25} decreases with increasing x. • The critical exponents behavior and scaling relation of the alloy series have been investigated. • Using M–H data, employing Modified Arrott plot and Kouvel–Fisher plot exponents are estimated. • The estimated critical exponent values match very well with the mean field theory. • Under a magnetic field maximum up to 5 T, normal magnetocaloric effect has been observed. - Abstract: This work reports the investigation of critical behavior of Co{sub 50−x}Ni{sub x}Cr{sub 25}Al{sub 25} (x = 0 and 5) and magneto caloric effect (MCE) of bulk Co{sub 2}CrAl full Heusler alloy system. The alloy series of Co{sub 50−x}Ni{sub x}Cr{sub 25}Al{sub 25} (x = 0, 1, 2, 3, 4 and 5) have been prepared using arc melting technique. The magnetic properties of all the samples have been studied in the temperature range of 5–300 K. The value of Curie temperature (T{sub C}) is found to decrease with increasing doping concentration of the Ni (substitution of Ni at Co site). The critical exponents behavior and scaling relation have been investigated using magnetic isotherms in Co{sub 50−x}Ni{sub x}Cr{sub 25}Al{sub 25} (x = 0 and 5) alloys. The critical exponents are estimated by various techniques such as, Modified Arrott plot, Kouvel–Fisher plot and critical isotherm technique. The value of critical exponents vicinity to the second order magnetic phase transition of Co{sub 50}Cr{sub 25}Al{sub 25} were found to be β = 0.488 (7), γ = 1.144 (16) and δ = 3.336 (5) with T{sub C} = 328.64 (5) K whereas for Co{sub 50}Ni{sub 5}Cr{sub 25}Al{sub 25} the values are β = 0.522 (13), γ = 1.014 (6) and δ = 3.043 (7) with T{sub C} = 285.71 (11). The critical exponent values for both the samples are almost similar to the value as predicted by mean field theory. This has been best explained by long range mean field like ferromagnetic interaction in the

  7. Calorimetry studies on U-Cr alloys

    International Nuclear Information System (INIS)

    A calorimetric study of Uranium-Chromium system is of interest on both basic and applied fronts. With the advent of U-Pu-Zr alloy as the fuel, in combination with ferritic-martensitic steel as the cladding material, the metal fuelled fast reactors constitute the second major step in Indian nuclear power program. In such a context, a fundamental investigation on the high temperature phase stability of U-Cr alloys is of particular relevance in getting further insight in to the complex issue of the metallurgical compatibility of ferritic steels with metallic Uranium-Zirconium fuel. It may be added that following U-Fe, and U-Zr binaries, the U-Cr constitutes one of the important subsystems of the complex U-Zr-Pu-Fe- Cr-Mn-Si-V-Nb-C-N multinary system. In the current study, the results of calorimetry investigations on U, U-2, 3, 7, 15wt. % Cr alloys are presented

  8. First principles analysis of hydrogen chemisorption on Pd-Re alloyed overlayers and alloyed surfaces

    DEFF Research Database (Denmark)

    Pallassana, Venkataraman; Neurock, Matthew; Hansen, Lars Bruno; Nørskov, Jens Kehlet

    2000-01-01

    Gradient corrected periodic density functional theory (DFT-GGA) slab calculations were used to examine the chemisorption of atomic hydrogen on various Pd-Re alloyed overlayers and uniformly alloyed surfaces. Adsorption was examined at 33% surface coverage, where atomic hydrogen preferred the three...... developed to extend the Hammer-Norskov surface reactivity model [Surf. Sci. 343, 211 (1995)] to the analysis of bimetallic Pd-Re alloyed systems. The hydrogen chemisorption energies are correlated linearly to the surface d-band center, which is weighted appropriately by the d-band coupling matrix elements...... for Pd and Re. The farther the weighted d-band center is shifted below the Fermi energy, the weaker is the interaction of atomic hydrogen with the alloyed Pd-Re surface. (C) 2000 American Institute of Physics....

  9. Establishing a Scientific Basis for Optimizing Compositions, Process Paths and Fabrication Methods for Nanostructured Ferritic Alloys for Use in Advanced Fission Energy Systems

    Energy Technology Data Exchange (ETDEWEB)

    Odette, G Robert; Cunningham, Nicholas J., Wu, Yuan; Etienne, Auriane; Stergar, Erich; Yamamoto, Takuya

    2012-02-21

    The broad objective of this NEUP was to further develop a class of 12-15Cr ferritic alloys that are dispersion strengthened and made radiation tolerant by an ultrahigh density of Y-Ti-O nanofeatures (NFs) in the size range of less than 5 nm. We call these potentially transformable materials nanostructured ferritic alloys (NFAs). NFAs are typically processed by ball milling pre-alloyed rapidly solidified powders and yttria (Y2O3) powders. Proper milling effectively dissolves the Ti, Y and O solutes that precipitate as NFs during hot consolidation. The tasks in the present study included examining alternative processing paths, characterizing and optimizing the NFs and investigating solid state joining. Alternative processing paths involved rapid solidification by gas atomization of Fe, 14% Cr, 3% W, and 0.4% Ti powders that are also pre-alloyed with 0.2% Y (14YWT), where the compositions are in wt.%. The focus is on exploring the possibility of minimizing, or even eliminating, the milling time, as well as producing alloys with more homogeneous distributions of NFs and a more uniform, fine grain size. Three atomization environments were explored: Ar, Ar plus O (Ar/O) and He. The characterization of powders and alloys occurred through each processing step: powder production by gas atomization; powder milling; and powder annealing or hot consolidation by hot isostatic pressing (HIPing) or hot extrusion. The characterization studies of the materials described here include various combinations of: a) bulk chemistry; b) electron probe microanalysis (EPMA); c) atom probe tomography (APT); d) small angle neutron scattering (SANS); e) various types of scanning and transmission electron microscopy (SEM and TEM); and f) microhardness testing. The bulk chemistry measurements show that preliminary batches of gas-atomized powders could be produced within specified composition ranges. However, EPMA and TEM showed that the Y is heterogeneously distributed and phase separated, but

  10. New Fuel Alloys Seeking Optimal Solidus and Phase Behavior for High Burnup and TRU Burning

    International Nuclear Information System (INIS)

    Recent modifications to fast reactor metallic fuels have been directed toward improving the melting and phase behaviors of the fuel alloy, for the purpose of ultra-high burnup and transuranic (TRU) burning. Improved melting temperatures increase the safety margin for uranium-based fast reactor fuel alloys, which is especially important for transuranic burning because the introduction of plutonium and neptunium acts to lower the alloy melting temperature. Improved phase behavior—single-phase, body-centered cubic—is desired because the phase is isotropic and the alloy properties are more predictable. An optimal alloy with both improvements was therefore sought through a comprehensive literature survey and theoretical analyses, and the creation and testing of some alloys selected by the analyses. Summarized here are those analyses, the impact of alloy modifications, and recent experimental results for selected pseudo-binary alloy systems that are hoped to accomplish the goals in a short timeframe. (author)

  11. 电力系统用LF21铝合金的电化学腐蚀行为%Electrochemical Corrosion Behavior of LF21 Aluminum Alloy Used in Electric Power System

    Institute of Scientific and Technical Information of China (English)

    杨萍; 黎学明; 宗庆彬; 邱妮; 姚强; 苗玉龙

    2012-01-01

    采用Tafel直线外推法、电化学阻抗谱和中性盐雾腐蚀试验研究了电力系统用LF21铝合金在5%NaCl溶液中的电化学腐蚀行为,利用SEM和EDS表征材料的腐蚀形态与腐蚀产物组成,并探讨腐蚀机理.结果表明,LF21铝合金在5%NaCl溶液中耐蚀性很差.随着电解液温度升高,铝合金的自腐蚀电位负移,腐蚀速率变大.电化学阻抗谱显示其容抗减小,膜电容下降,合金表面的保护膜被破坏.LF21铝合金在NaCl介质中的腐蚀主要以点蚀为主,形成较深的腐蚀坑,点蚀部位O含量明显增高.%The electrochemical behavior of LF21 aluminum alloy,as a major base materials used in electric power system,in 5% NaCl solution were investigated by Tafel linear extrapolation method,electrochemical impedance spectroscopy technique and neutral salt spray test.The surface morphology and chemical composition of the corrosion product of the alloy were examined by scanning electron microscope and energy dispersive spectrometer,respectively.The results showed that LF21 aluminum alloy exhibited poor anti-corrosion performance in 5%NaCl solution.When the temperature of solution increased,the corrosion potential of LF21 aluminum alloy shifted negatively,and the corrosion current density increased.Meanwhile,the capacitive resistance and film capacity decreased with the increasing of the solution temperature,implying that the protection film on the surface of material was deteriorated to some extent.The major corrosion form of LF21 aluminum alloy in NaCl solution was pitting corrosion,and the corrosion resulted in much deeper corrosion pits.

  12. Machining of titanium alloys

    CERN Document Server

    2014-01-01

    This book presents a collection of examples illustrating the resent research advances in the machining of titanium alloys. These materials have excellent strength and fracture toughness as well as low density and good corrosion resistance; however, machinability is still poor due to their low thermal conductivity and high chemical reactivity with cutting tool materials. This book presents solutions to enhance machinability in titanium-based alloys and serves as a useful reference to professionals and researchers in aerospace, automotive and biomedical fields.

  13. Pareto-optimal alloys

    DEFF Research Database (Denmark)

    Bligaard, Thomas; Johannesson, Gisli Holmar; Ruban, Andrei; Skriver, Hans Lomholt; Jacobsen, Karsten Wedel; Nørskov, Jens Kehlet

    2003-01-01

    cost. In this letter we present a database consisting of the lattice parameters, bulk moduli, and heats of formation for over 64 000 ordered metallic alloys, which has been established by direct first-principles density-functional-theory calculations. Furthermore, we use a concept from economic theory......, the Pareto-optimal set, to determine optimal alloy solutions for the compromise between low compressibility, high stability, and cost....

  14. Development of surface composite based on Mg–Al–Ni system on AZ31 magnesium alloy and evaluation of formation mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Abdollahi, S.H.; Karimzadeh, F., E-mail: karimzadeh_f@cc.iut.ac.ir; Enayati, M.H.

    2015-02-25

    Highlights: • This research showed that by applying friction stir processing (FSP) in-situ surface composite based on Mg–Al/Ni alloying systems is produced on AZ31 plate under different FSP passes. • Thermodynamic and kinetic study of interfacial solid state reactions confirmed phase formation during different FSP passes. • Moreover, the effective Gibbs free energy of formation graphs for the compounds were plotted at 711 K. • Based on kinetic standpoint, schematic diagram of Mg–Ni intermetallic compounds during difference FSP passes is plotted. • Due to presence of intermetallic phases the mean hardness of the stir zone reached about 106 Hv, which is about two times higher than the base metal. - Abstract: The in-situ synthesis of Mg–Al–Ni composite on the surface of AZ31 plate by friction stir processing (FSP), has been investigated in this article. The unprocessed AZ31 plate consisted of grains of 25 μm size. By increasing the number of FSP passes from one to five, the grain size of the AZ31 plate decreased to 7.5 and 3 μm, respectively. A uniform distribution of the reinforcements was also obtained by increasing the number of FSP passes. Based on the results of X-ray diffraction (XRD) and Energy dispersive spectrometry (EDS) analyses, Mg{sub 2}Ni and Al{sub 3}Ni{sub 2} intermetallic compounds are in-situ formed by a single-pass FSP of the composite specimens. By increasing the number of FSP passes, the amounts of Mg{sub 2}Ni and Al{sub 3}Ni{sub 2} compounds are dramatically reduced and AlNi and MgNi{sub 2} intermetallic compounds take their place. Thermodynamic and kinetic of interfacial solid state reactions were studied to determine the reactive mechanisms and phase evolutions during different passes of FSP. The maximum amount of hardness (∼106 Hv), was obtained for the composite sample after five passes of FSP.

  15. Texture in low-alloyed uranium alloys

    International Nuclear Information System (INIS)

    The dependence of the preferred orientation of cast and heat-treated polycrystalline adjusted uranium and uranium -0.1 w/o chromium alloys on the production process was studied. The importance of obtaining material free of preferred orientation is explained, and a survey of the regular methods to determine preferred orientation is given. Dilatometry, tensile testing and x-ray diffraction were used to determine the extent of the directionality of these alloys. Data processing showed that these methods are insufficient in a case of a material without any plastic forming, because of unreproducibility of results. Two parameters are defined from the results of Schlz's method diffraction test. These parameters are shown theoretically and experimentally (by extreme-case samples) to give the deviation from isotropy. Application of these parameters to the examined samples showes that cast material has preferred orientation, though it is not systematic. This preferred orientation was reduced by adequate heat treatments

  16. WC-3015 alloy (high-temperature alloy)

    International Nuclear Information System (INIS)

    WC-3015 Nb alloy containing 28 to 30 Hf, 1 to 2 Zr, 13 to 16 W, 0 to 4 Ta, 0 to 5 Ti, 0.07 to 0.33 C, less than or equal to 0.02 N, less than or equal to 0.03 O, less than or equal to 0.001 H was developed for use at high temperature in oxidizing environments. Its composition can be tailored to meet specific requirements. When WC-3015 is exposed to O at elevated temperature, Hf and Nb oxidized preferentially and HfO2 dissolves in Nb2O5 to form 6HfO-Nb2O5. This complex oxide has a tight cubic lattice which resists the diffusion of O into the substrate. During 24-h exposure to air at 24000F, the alloy oxidizes to a depth of approximately 0.035 in. with a surface recession of 0 to 0.004 in. Oxidation resistance of WC-3015 welds and base material can be further enhanced greatly by applying silicide coatings. WC-3015 alloy can be machined by conventional and electrical-discharge methods. It can be hot worked readily by extrusion, forging or rolling. Cold working can be used at room or elevated temperature. It can be welded by the electron-beam or Tig processes. Physical constants, typical mechanical properties at 75 to 24000F, and effects of composition and heat treatment on tensile and stress-rupture properties of the alloy are tabulated

  17. A bidirectional shape memory alloy folding actuator

    International Nuclear Information System (INIS)

    This paper presents a low-profile bidirectional folding actuator based on annealed shape memory alloy sheets applicable for meso- and microscale systems. Despite the advantages of shape memory alloys—high strain, silent operation, and mechanical simplicity—their application is often limited to unidirectional operation. We present a bidirectional folding actuator that produces two opposing 180° motions. A laser-patterned nickel alloy (Inconel 600) heater localizes actuation to the folding sections. The actuator has a thin ( < 1 mm) profile, making it appropriate for use in robotic origami. Various design parameters and fabrication variants are described and experimentally explored in the actuator prototype. (paper)

  18. Methods for Electrodepositing Composition-Modulated Alloys

    DEFF Research Database (Denmark)

    Leisner, Peter; Nielsen, Christian Bergenstof; Tang, Peter Torben; Dörge, Tommy C.; Møller, Per

    1996-01-01

    Materials exhibiting unique mechanical, physical and chemical properties can be obtained by combining thin layers of different metals or alloys forming a multilayered structure. Two general techniques exist for electrodepositing composition-modulated alloy (CMA) materials; dual-bath and single......-bath plating. For both techniques a number of variations exist. The most suitable technique and variation for the manufacture of a certain CMA material is highly dependent on the metals included in the given CMA system and on the dimensions of the multilayered structure. In this paper, the main principles of...

  19. Liquid eutectic alloys as a cluster solutions

    OpenAIRE

    I. Shcherba; Shtablavyi, I.; S. Mudry

    2008-01-01

    Purpose: In this research work the results of structure studies for Al0.88Si0.12, Bi0.995Cu0.005, Al0.83Cu0.17 eutecticand Co0.05Cu0.95 peritectic melts have been presented. The structure parameters of molten alloys are comparedwith ones for liquid pure components and with model values.Design/methodology/approach: The structure in liquid state has been studied with use of X-raydiffractometer containing special attachment for investigation of liquid metallic alloys. The system was equippedwith...

  20. Microstructures and oxidation behavior of some Molybdenum based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ray, Pratik Kumar [Iowa State Univ., Ames, IA (United States)

    2011-01-01

    The advent of Ni based superalloys revolutionized the high temperature alloy industry. These materials are capable of operating in extremely harsh environments, comprising of temperatures around 1050 C, under oxidative conditions. Demands for increased fuel efficiency, however, has highlighted the need for materials that can be used under oxidative conditions at temperatures in excess of 1200 C. The Ni based superalloys are restricted to lower temperatures due to the presence of a number of low melting phases that melt in the 1250 - 1450 C, resulting in softening of the alloys above 1000 C. Therefore, recent research directions have been skewed towards exploring and developing newer alloy systems. This thesis comprises a part of such an effort. Techniques for rapid thermodynamic assessments were developed and applied to two different systems - Mo-Si alloys with transition metal substitutions (and this forms the first part of the thesis) and Ni-Al alloys with added components for providing high temperature strength and ductility. A hierarchical approach towards alloy design indicated the Mo-Ni-Al system as a prospective candidate for high temperature applications. Investigations on microstructures and oxidation behavior, under both isothermal and cyclic conditions, of these alloys constitute the second part of this thesis. It was seen that refractory metal systems show a marked microstructure dependence of oxidation.

  1. Microstructure and Mechanical Properties of Solution Heat-Treated Alloy 617 ODS Alloy

    International Nuclear Information System (INIS)

    Alloy 617 is a solution hardened Ni-based Superalloy containing Cr, Co, Mo, and Fe, and is among the best candidate materials for the key components of VHTR (Very High Temperature Reactor) system. As an alternative, Oxide Dispersion Strengthened (ODS) Ni-based superalloys, are known to possess superior high temperature mechanical properties and long-term high temperature microstructural stability due to the nano sized oxide dispersoids, which effectively hinder the dislocation motion at high temperature. This study is focused on the fabrication and characterization of nanosized oxide dispersion strengthened alloy 617. The influences of alloy composition and processing variables such as the content of Y2O3, hot extrusion ratio, and hydrogen reduction on the microstructure and mechanical properties were studied. From the analyses of microstructure of solution heat treated Alloy 617 ODS alloy specimens, a proper solid solution heat treatment temperature to reduce carbides is 1250 .deg. C. The major phases present in the alloy 617 ODS were found to be M23C6 and Al-O

  2. Steam generated conversion coating on aluminium alloys

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Jellesen, Morten Stendahl; Ambat, Rajan

    into functional conversion coatings in order to enhance corrosion resistance and adhesion to paint systems. Chromium based conversion coatings have been extensively used on aluminium alloys to improve adhesion of subsequent paint layers and corrosion resistance. However, the use of hexavalent chromium...

  3. Corrosion, Al containing corrosion barriers and mechanical properties of steels foreseen as structural materials in liquid lead alloy cooled nuclear systems

    International Nuclear Information System (INIS)

    A key problem in development of heavy liquid metal cooled nuclear energy and transmutation reactors is the corrosion of structural and fuel. Above 500 oC steels have to be protected by stable, thin oxide scales. A well understood measure is alloying of stable oxide formers into the surface. Two methods, alloying an Al layer into the steel surface using pulsed electron beams (GESA - gepulste Elektronenstrahlanlage) and coating the surface with an Al-alloy with subsequent GESA treatment are applied. In the range of 4-10 wt% Al on the surface a stable thin alumina scale is formed by Al diffusion to the surface and selective oxidation. The alumina scale grows only very slowly and prevents migration of oxygen into the steel as well as migration of steel components onto the surface. A number of corrosion experiments showed the good protective behaviour of Al scales in LBE with 10-6 wt% oxygen up to 650 oC and for exposure times up to 10,000 h. Furthermore the influence of parameters like stresses in the cladding wall, creep behaviour, different flow velocities of the LBE and changing temperatures and oxygen concentrations in LBE is discussed. This paper will provide an overview on the activities concerning Pb-PbBi corrosion and corrosion protection performed at the Institute of Pulsed Power and Microwave Technology (IHM) at the KIT.

  4. Alloy 800 welding experience at UKAEA Springfields

    International Nuclear Information System (INIS)

    Investigatins into the welding of alloy 800 at the Reactor Fuel Element Laboratories, Springfields, commenced about three years ago following an extended development programme on tube to tube plate welding of low alloy and stainless steels for the Prototype Fast Reactor. The techniques and approach developed for critical fuel element welding applications had proved equally suitable for the precision welding requirements on the much heavier sections of heat exchangers. It had been demonstrated that the same control of weld quality and profile could be achieved with consistency and the permissible range of critical parameters could be readily defined. Because of this, development work was continued to include other materials, such as alloy 800, which might be of potential use. The tungsten inert gas (T.I.G.) arc welding process is used, and the equipment, including the control system, is described. Tube to tube-plate welding, and tube to tube butt welding, are discussed. (author)

  5. Trace hydrogen extraction from liquid lithium tin alloy

    International Nuclear Information System (INIS)

    In order to finish the design of tritium extraction system (TES) of fusion fission hybrid reactor (FFHR) tritium blanket, involving the dynamic mathematical model of liquid metal in contact with a gaseous atmosphere, approximate mathematical equation of tritium in lithium tin alloy was deduced. Moreover, carrying process used for trace hydrogen extraction from liquid lithium tin alloy was investigated with hydrogen being used to simulate tritium in the study. The study results indicate that carrying process is effective way for hydrogen extraction from liquid lithium tin alloy, and the best flow velocity of carrier gas is about 4 L/min under 1 kg alloy temperatures and carrying numbers are the main influencing factors of hydrogen number. Hydrogen extraction efficiency can reach 85% while the alloy sample is treated 6 times at 823 K. (authors)

  6. Cr{sub 2}Nb-based alloy development

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.T.; Tortorelli, P.F.; Horton, J.A. [Oak Ridge National Lab., TN (United States)] [and others

    1996-08-01

    Alloys of Cr-Cr{sub 2}Nb with exceptionally high strength at 1200{degrees}C have been developed. However, these compositions suffer from limited ductility and toughness at room temperature. Despite improvements from processing modifications, as-fabricated defects still limit room temperature mechanical behavior. In contrast, an alloy system with only a small mismatch of the coefficients of thermal expansion of the two phases, Cr-Cr{sub 2}Zr, showed good fabricability. However, these alloys are weaker than Cr-Cr{sub 2}Nb compositions at high temperatures and have poor oxidation resistance. Silicide coatings can provide high-temperature oxidation and sulfidation protection of these alloys. Improvements in room temperature mechanical properties of Laves-phase-strengthened alloys will rely on further development based on increasing the ductility of the matrix phase by impurity control and compositional modifications.

  7. Refractory alloy technology for space nuclear power applications

    International Nuclear Information System (INIS)

    Purpose of this symposium is twofold: (1) to review and document the status of refractory alloy technology for structural and fuel-cladding applications in space nuclear power systems, and (2) to identify and document the refractory alloy research and development needs for the SP-100 Program in both the short and the long term. In this symposium, an effort was made to recapture the space reactor refractory alloy technology that was cut off in midstream around 1973 when the national space nuclear reactor program began in the early 1960s, was terminated. The six technical areas covered in the program are compatibility, processing and production, welding and component fabrication, mechanical and physical properties, effects of irradiation, and machinability. The refractory alloys considered are niobium, molybdenum, tantalum, and tungsten. Thirteen of the 14 pages have been abstracted separately. The remaining paper summarizes key needs for further R and D on refractory alloys

  8. Refractory alloy technology for space nuclear power applications

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, R.H. Jr.; Hoffman, E.E. (eds.)

    1984-01-01

    Purpose of this symposium is twofold: (1) to review and document the status of refractory alloy technology for structural and fuel-cladding applications in space nuclear power systems, and (2) to identify and document the refractory alloy research and development needs for the SP-100 Program in both the short and the long term. In this symposium, an effort was made to recapture the space reactor refractory alloy technology that was cut off in midstream around 1973 when the national space nuclear reactor program began in the early 1960s, was terminated. The six technical areas covered in the program are compatibility, processing and production, welding and component fabrication, mechanical and physical properties, effects of irradiation, and machinability. The refractory alloys considered are niobium, molybdenum, tantalum, and tungsten. Thirteen of the 14 pages have been abstracted separately. The remaining paper summarizes key needs for further R and D on refractory alloys. (DLC)

  9. The Formablity of AZ31B Magnesium Alloy Sheet

    Institute of Scientific and Technical Information of China (English)

    WANG Lingyun; LU Zhiwen; ZHAO Yazhong; QIU Xiaogang

    2006-01-01

    The forming limit diagrams(FLD)of AZ31B magnesium alloy sheet were tested by means of the electro etching grid method based on the forming experiment of magnesium alloy sheet carried out with a BCS-30D sheet forming testing machine and the strain testing analysis made with an advanced ASAME automatic strain measuring system. Experiments show that, at room temperature, the mechanical properties and deep drawing performance of AZ31B cold-rolled magnesium alloy sheet were so poor that it failed to test the forming limit diagrams without an ideal forming and processing capacity, while the hot-rolled magnesium alloy sheet was of a little better plasticity and forming performance after testing its forming limit diagrams. It can be concluded that the testing of the forming limit curves (FLC)offers the theoretical foundation for the drawing of the deep drawing and forming process of magnesium alloy sheet.

  10. Electrochemical preparation La-Co magnetic alloy films from dimethylsulfoxide

    International Nuclear Information System (INIS)

    The electrochemical behavior of La3+ ion is investigated on a Pt electrode in the 2.5 x 10-3 mol L-1 La(ClO4)3-7.5 x 10-2 mol L-1 LiClO4-dimethylsulfoxide (DMSO) system. The experimental results indicate that the reduction of La3+ ion is irreversible. Some electrochemical parameters are measured. The pulse deposition technique is used to prepare La-Co alloy films. The surfaces of La-Co alloy films are uniform, compact and showed a metallic luster. The grain sizes of La-Co alloy observed by scanning electron microscope (SEM) are about 100 nm. La-Co alloy film is amorphous as proven by the X-ray diffraction (XRD). The magnetic properties of the amorphous La-Co alloy film are measured

  11. Microelectrochemical and corrosion behaviour of metal alloy waste forms

    International Nuclear Information System (INIS)

    Within the USDOE Fuel Cycle Research and Development Program steel-based alloys have shown promise as potential waste forms for Tc-based waste streams produced from spent fuel processing. Waste stream components are alloyed with steel to create an alloy with a complex microstructure. Surface analytical techniques (SEM, EDS) coupled with long-term corrosion studies and electrochemical techniques have been used to analyze the corrosion behaviour of this material. Due to the complex alloy structure it is difficult to determine which phases are active or passive to corrosion. A microelectrochemical cell system has been employed to isolate and study individual phases and regions to separate their corrosion behaviours. Such analyses lead to a much clearer picture of alloy corrosion processes when coupled with bulk studies. (author)

  12. Effect of filtration on reoxidation proceses in aluminium alloys

    Directory of Open Access Journals (Sweden)

    D. Bolibruchova

    2010-01-01

    Full Text Available This article is focused on reoxidation processes during filtration of aluminium alloys. Many of our experimental works pointed out, that using filtration media placed in gating system causes reoxidation of poured aluminium alloy. Main aim of our latest work was to validate our arguments, that filter in gating system can be considered as obstacle for continuous pouring, with help of computer simulations. This article is only a small part of our researches focused on reoxidation processes during filtration of aluminium alloys.

  13. Correlation between diffusion barriers and alloying energy in binary alloys

    DEFF Research Database (Denmark)

    Vej-Hansen, Ulrik Grønbjerg; Rossmeisl, Jan; Stephens, Ifan; Schiøtz, Jakob

    2016-01-01

    In this paper, we explore the notion that a negative alloying energy may act as a descriptor for long term stability of Pt-alloys as cathode catalysts in low temperature fuel cells.......In this paper, we explore the notion that a negative alloying energy may act as a descriptor for long term stability of Pt-alloys as cathode catalysts in low temperature fuel cells....

  14. Precipitation Hardening and Statistical Modeling of the Aging Parameters and Alloy Compositions in Al-Cu-Mg-Ag Alloys

    Science.gov (United States)

    Al-Obaisi, A. M.; El-Danaf, E. A.; Ragab, A. E.; Soliman, M. S.

    2016-06-01

    The addition of Ag to Al-Cu-Mg systems has been proposed to replace the existing high-strength 2xxx and 7xxx Al alloys. The aged Al-Cu-Mg-Ag alloys exhibited promising properties, due to special type of precipitates named Ω, which cooperate with other precipitates to enhance the mechanical properties significantly. In the present investigation, the effect of changing percentages of alloying elements, aging time, and aging temperature on the hardness values was studied based on a factorial design. According to this design of experiments (DOE)—23 factorial design, eight alloys were cast and hot rolled, where (Cu, Mg, and Ag) were added to aluminum with two different levels for each alloying element. These alloys were aged at different temperatures (160, 190, and 220 °C) over a wide range of time intervals from 10 min. to 64 h. The resulting hardness data were used as an input for Minitab software to model and relate the process variables with hardness through a regression analysis. Modifying the alloying elements' weight percentages to the high level enhanced the hardness of the alloy with about 40% as compared to the alloy containing the low level of all alloying elements. Through analysis of variance (ANOVA), it was figured out that altering the fraction of Cu had the greatest effect on the hardness values with a contribution of about 49%. Also, second-level interaction terms had about 21% of impact on the hardness values. Aging time, quadratic terms, and third-level interaction terms had almost the same level of influence on hardness values (about 10% contribution). Furthermore, the results have shown that small addition of Mg and Ag was enough to improve the mechanical properties of the alloy significantly. The statistical model formulated interpreted about 80% of the variation in hardness values.

  15. Thermodynamic properties of average-atom interatomic potentials for alloys

    Science.gov (United States)

    Nöhring, Wolfram Georg; Curtin, William Arthur

    2016-05-01

    The atomistic mechanisms of deformation in multicomponent random alloys are challenging to model because of their extensive structural and compositional disorder. For embedded-atom-method interatomic potentials, a formal averaging procedure can generate an average-atom EAM potential and this average-atom potential has recently been shown to accurately predict many zero-temperature properties of the true random alloy. Here, the finite-temperature thermodynamic properties of the average-atom potential are investigated to determine if the average-atom potential can represent the true random alloy Helmholtz free energy as well as important finite-temperature properties. Using a thermodynamic integration approach, the average-atom system is found to have an entropy difference of at most 0.05 k B/atom relative to the true random alloy over a wide temperature range, as demonstrated on FeNiCr and Ni85Al15 model alloys. Lattice constants, and thus thermal expansion, and elastic constants are also well-predicted (within a few percent) by the average-atom potential over a wide temperature range. The largest differences between the average atom and true random alloy are found in the zero temperature properties, which reflect the role of local structural disorder in the true random alloy. Thus, the average-atom potential is a valuable strategy for modeling alloys at finite temperatures.

  16. Characterization of thermally stable Ir-Ta alloy thin films deposited by sputtering

    OpenAIRE

    Watanabe, E; Abe, Y.; Sasaki, K; Iura, S.; 阿部, 良夫; 佐々木, 克孝

    2004-01-01

    Ir-Ta alloy thin films were deposited on Si0_2/Si substrates by a magnetron sputtering system using pure Ar as sputtering gas. The lr/Ta composition ratio of the alloy films was varied by changing the number of Ta chips on an lr target. The crystal structure of the alloy films changed from fcc-Ir to lr_3Ta, α-(Ir,Ta), Ta_3Ir, and bcc-Ta with increasing Ta content. Post-deposition annealing of the alloy films was carried out in oxygen at temperatures from 300℃ to 800℃ for 1 hour. The alloy fil...

  17. Controllable galvanic synthesis of triangular Ag-Pd alloy nanoframes for efficient electrocatalytic methanol oxidation.

    Science.gov (United States)

    Xu, Lin; Luo, Zhimin; Fan, Zhanxi; Yu, Sijia; Chen, Junze; Liao, Yusen; Xue, Can

    2015-06-01

    Triangular Ag-Pd alloy nanoframes were successfully synthesized through galvanic replacement by using Ag nanoprisms as sacrificial templates. The ridge thickness of the Ag-Pd alloy nanoframes could be readily tuned by adjusting the amount of the Pd source during the reaction. These obtained triangular Ag-Pd alloy nanoframes exhibit superior electrocatalytic activity for the methanol oxidation reaction as compared with the commercial Pd/C catalyst due to the alloyed Ag-Pd composition as well as the hollow-framed structures. This work would be highly impactful in the rational design of future bimetallic alloy nanostructures with high catalytic activity for fuel cell systems. PMID:25925988

  18. Influence of alloying elements and nitrogen content on deformation resistance of chromium-nickel stainless steels

    International Nuclear Information System (INIS)

    Four groups of steels with a type Kh20N15 matrix differing in the contents of nitrogen and additional alloying element (Cu, Si, V or Nb) were studied for the influence of the alloying system on deformation resistance in hot rolling. The one-pass rolling was carried out at 900, 1000, 1100 and 1200 deg C with 20, 40 and 60 % reductions. Experimental data statistical processing showed that vanadium alloying results in a sharp increase of nitrogen content influence comparable with strain hardening. The hardening effect in copper- and silicon-containing alloys almost is independent of nitrogen concentration. Niobium-containing alloys lie between two above mentioned groups

  19. A super-ductile alloy for the die-casting of aluminium automotive body structural components

    OpenAIRE

    Watson, D.; Ji, S; Fan, Z.

    2014-01-01

    Super-ductile die-cast aluminium alloys are critical to future light-weighting of automotive body structures. This paper introduces a die-cast aluminium alloy that can satisfy the requirements of these applications. After a review of currently available alloys, the requirement of a die-cast aluminium alloy for automotive body structural parts is proposed and an Al-Mg-Si system is suggested. The effect of the alloying elements, in the composition, has been investigated on the microstructure an...

  20. The Eighth International Ural Seminar Radiation damage physics of metals and alloys. Abstracts

    International Nuclear Information System (INIS)

    The book includes abstracts of the Eight International Ural Seminar Radiation damage physics of metals and alloys (Snezhinsk, 23 February - 1 March, 2009). Reports on the characteristics of point defects in different alloys and compounds including Fe-Cr(Ni) systems are presented. Effects of irradiation and strong deformation on changing microstructure and properties of metals and alloys are discussed. Gaseous impurities in irradiated metals and alloys, materials problems in nuclear and thermonuclear powers, physical properties and atomic defects in actinides and actinide alloys, and model analogs are discussed. Reports on physics of radiation effects in magnetics, superconductors, semiconductors and nonconductors, as well as technology and experimental technique, ion implantation are performed

  1. Transparent conductive Nb-doped TiO2 films deposited by reactive dc sputtering using Ti-Nb alloy target, precisely controlled in the transition region using impedance feedback system

    Science.gov (United States)

    Oka, Nobuto; Sanno, Yuta; Jia, Junjun; Nakamura, Shin-ichi; Shigesato, Yuzo

    2014-05-01

    In this study, a stable reactive sputtering process using a Ti-Nb alloy target was achieved by applying a plasma impedance feedback system. High-quality transparent conductive Nb-doped TiO2 (Nb:TiO2) films were fabricated with high reproducibility. The films were deposited on unheated substrate and subsequently annealed at 873 K under vacuum conditions (below 6.0 × 10-4 Pa) for 1 h. During reactive sputtering, the feedback system precisely controlled the oxidation of the target surface in the so-called transition region. The post-annealing process yielded polycrystalline Nb:TiO2 films whose lattice defects decreased with increasing Nb concentration. An extremely low resistivity (7.2 × 10-4 Ω cm) was achieved for Nb:TiO2 film with 60-70% transmittance in the visible region. The reactive sputtering using Ti-Nb alloys is considered to be a strong candidate for industrial-scale thin-film deposition. Furthermore, it can also control the metal-oxygen stoichiometry of Nb:TiO2 films precisely to achieve desirable properties for each industrial application.

  2. INVESTIGATION OF MAGNESIUM ALLOYS MACHINABILITY

    Directory of Open Access Journals (Sweden)

    Berat Barıs BULDUM

    2013-01-01

    Full Text Available Magnesium is the lightest structural metal. Magnesium alloys have a hexagonal lattice structure, which affects the fundamental properties of these alloys. Plastic deformation of the hexagonal lattice is more complicated than in cubic latticed metals like aluminum, copper and steel. Magnesium alloy developments have traditionally been driven by industry requirements for lightweight materials to operate under increasingly demanding conditions. Magnesium alloys have always been attractive to designers due to their low density, only two thirds that of aluminium and its alloys [1]. The element and its alloys take a big part of modern industry needs. Especially nowadays magnesium alloys are used in automotive and mechanical (trains and wagons manufacture, because of its lightness and other features. Magnesium and magnesium alloys are the easiest of all metals to machine, allowing machining operations at extremely high speed. All standard machining operations such as turning, drilling, milling, are commonly performed on magnesium parts.

  3. Structural thermodynamics of alloys

    CERN Document Server

    Manenc, Jack

    1973-01-01

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

  4. INVESTIGATION OF MAGNESIUM ALLOYS MACHINABILITY

    OpenAIRE

    Berat Barıs BULDUM; Aydın SIK; Iskender OZKUL

    2013-01-01

    Magnesium is the lightest structural metal. Magnesium alloys have a hexagonal lattice structure, which affects the fundamental properties of these alloys. Plastic deformation of the hexagonal lattice is more complicated than in cubic latticed metals like aluminum, copper and steel. Magnesium alloy developments have traditionally been driven by industry requirements for lightweight materials to operate under increasingly demanding conditions. Magnesium alloys have always been attra...

  5. Productive Machining of Titanium Alloys

    OpenAIRE

    Čejka, Libor

    2013-01-01

    This diploma thesis is focused on a productive machining of titanium alloys. At the beginning it deals about titanium and its alloys. It describes chip generation mechanism, tool blunting and surface quality. Further it contains modern strategies of efficient titanium alloys machining. Then it analyzes contemporary manufacturing technology of hinge made of titanium alloy Ti-6Al-4V in Frentech Aerospace s.r.o. company, and at the end finds possibility of savings by inovation of roughing process.

  6. De-alloyed platinum nanoparticles

    Science.gov (United States)

    Strasser, Peter; Koh, Shirlaine; Mani, Prasanna; Ratndeep, Srivastava

    2011-08-09

    A method of producing de-alloyed nanoparticles. In an embodiment, the method comprises admixing metal precursors, freeze-drying, annealing, and de-alloying the nanoparticles in situ. Further, in an embodiment de-alloyed nanoparticle formed by the method, wherein the nanoparticle further comprises a core-shell arrangement. The nanoparticle is suitable for electrocatalytic processes and devices.

  7. Hydrogen in titanium alloys

    International Nuclear Information System (INIS)

    The titanium alloys that offer properties worthy of consideration for fusion reactors are Ti-6Al-4V, Ti-6Al-2Sn-4Zr-2Mo-Si (Ti-6242S) and Ti-5Al-6Sn-2Zr-1Mo-Si (Ti-5621S). The Ti-6242S and Ti-5621S are being considered because of their high creep resistance at elevated temperatures of 5000C. Also, irradiation tests on these alloys have shown irradiation creep properties comparable to 20% cold worked 316 stainless steel. These alloys would be susceptible to slow strain rate embrittlement if sufficient hydrogen concentrations are obtained. Concentrations greater than 250 to 500 wppm hydrogen and temperatures lower than 100 to 1500C are approximate threshold conditions for detrimental effects on tensile properties. Indications are that at the elevated temperature - low hydrogen pressure conditions of the reactors, there would be negligible hydrogen embrittlement

  8. Welding of refractory alloys

    International Nuclear Information System (INIS)

    This review primarily summarizes welding evaluations supported by NASA-Lewis Research Center in the 1960s. A literature search run in preparation for this review indicates that more recent work is modest by comparison. Hence, this review restates these accomplishments briefly and addresses opportunities which have evolved in welding technology (such as lasers) in the intervening decade. Emphasis in this review is given to tantalum- and niobium-base alloys. Considerable work was also done to assure that a consistent comparison was made with tungsten. A wide variety of candidate alloys derived primarily from developments directed at aircraft propulsion applications were available. Early efforts by NASA were directed at screening studies to select promising structural alloys for the space power application. This objective required fine tuning of welding procedures, e.g., the demonstration of stringent standards for control of welding atmosphere to assure good corrosion resistance in liquid alkali metals. 16 figures, 6 tables

  9. Shape Memory Alloys

    Directory of Open Access Journals (Sweden)

    Deexith Reddy

    2016-07-01

    Full Text Available Shape memory alloys (SMAs are metals that "remember" their original shapes. SMAs are useful for such things as actuators which are materials that "change shape, stiffness, position, natural frequency, and other mechanical characteristics in response to temperature or electromagnetic fields" The potential uses for SMAs especially as actuators have broadened the spectrum of many scientific fields. The study of the history and development of SMAs can provide an insight into a material involved in cutting-edge technology. The diverse applications for these metals have made them increasingly important and visible to the world. This paper presents the working of shape memory alloys , the phenomenon of super-elasticity and applications of these alloys.

  10. Double Glow Plasma Surface Alloyed Burn-resistant Titanium Alloy

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ping-ze; XU Zhong; HE Zhi-yong; ZHANG Gao-hui

    2004-01-01

    Conventional titanium alloy may be ignited and burnt under high temperature, high pressure and high gas flow velocity condition. In order to avoid this problem, we have developed a new kind of burn-resistant titanium alloy-double glow plasma surface alloying burn-resistant titanium alloy. Alloying element Cr, Mo, Cu are induced into the Ti-6Al-4V and Ti-6.5Al-0.3Mo-l.5Zr-0.25Si substrates according to double glow discharge phenomenon, Ti-Cr ,Ti-Mo, Ti-Cu binary burn-resistant alloy layers are formed on the surface of Ti-6Al-4V and Ti-6.5Al-0.3Mo-l.5Zr-0.25Si alloys. The depth of the surface burn-resistant alloy layer can reach to above 200 microns and alloying element concentration can reach 90%.Burn-resistant property experiments reveal that if Cr concentration reach to 14%, Cu concentration reach to 12%, Mo concentration reach to 10% in the alloying layers, ignition and burn of titanium alloy can be effectively avoided.

  11. Double Glow Plasma Surface Alloyed Burn-resistant Titanium Alloy

    Institute of Scientific and Technical Information of China (English)

    ZHANGPing-ze; XUZhong; HEZhi-yong; ZHANGGao-hui

    2004-01-01

    Conventional titanium alloy may be ignited and burnt under high temperature, high pressure and high gas flow velocity condition. In order to avoid this problem, we have developed a new kind of burn-resistant titanium alloy-double glow plasma surface alloying burn-resistant titanium alloy. Alloying element Cr, Mo, Cu are induced into the Ti-6A1-4V and Ti-6.5Al-0.3Mo-1.5Zr-0.25Si substrates according to double glow discharge phenomenon, Ti-Cr ,Ti-Mo, Ti-Cu binary burn-resistant alloy layers are formed on the surface of Ti-6A1-4V and Ti-6.5Al-0.3Mo-1.5Zr-0.25Si alloys. The depth of the surface burn-resistant alloy layer can reach to above 200 microns and alloying element concentration can reach 90%. Burn-resistant property experiments reveal that if Cr concentration reach to 14%, Cu concentration reach to 12%, Mo concentration reach to 10% in the alloying layers, ignition and burn of titanium alloy can be effectively avoided.

  12. Liquid eutectic alloys as a cluster solutions

    Directory of Open Access Journals (Sweden)

    I. Shcherba

    2008-11-01

    Full Text Available Purpose: In this research work the results of structure studies for Al0.88Si0.12, Bi0.995Cu0.005, Al0.83Cu0.17 eutecticand Co0.05Cu0.95 peritectic melts have been presented. The structure parameters of molten alloys are comparedwith ones for liquid pure components and with model values.Design/methodology/approach: The structure in liquid state has been studied with use of X-raydiffractometer containing special attachment for investigation of liquid metallic alloys. The system was equippedwith special camera for sample, filled with pure helium in order to avoid the oxidation. Experimental data wereinterpreted with using of random atomic distribution model and self-associated one.Findings: The research has shown that structure of liquid alloys Al0.88Si0.12, Bi0.995Cu0.005, Al0.83Cu0.17 andCo0.05Cu0.95 shows the deviation from random atomic distribution model and these alloys in liquid state attemperatures not far from melting point can be considered as cluster solutions.Practical implications: Existence of clusters in eutectic and peritectic melts influence the structure andproperties of corresponding solid alloys, that is important for casting, soldering, welding and at producing ofcomposite materials on the base of eutectic matrix.Originality/value: Cluster structure of eutectic melts is responsible for behaviour of structure and physicalchemicalproperties. The change of this structure allows to improve the properties of solidificated alloys, bothcrystalline and amorphous.

  13. Machining of Titanium Alloys

    OpenAIRE

    Karásek, Jan

    2008-01-01

    The main goal of this work is the analysis of manufacturing costs for the component of wheel´s blower. Followed by setting up the size of specific cutting force for milling operation of the titanium alloy Ti-Al6-Mo2-Cr2-Fe-Si, the used tool was a milling cutter which is made out of sintered carbide with conical and spherical face. The final values which are at intervals of 1500 to 1800 MPa were compared with the values of the Sandvik Coromant firm kc = 1690 MPa, for titanium alloy with the st...

  14. Shape memory effect alloys

    International Nuclear Information System (INIS)

    Although the pseudo- or super-elasticity phenomena and the shape memory effect were known since the 1940's, the enormous curiosity and the great interest to their practical applications emerged with the development of the NITINOL alloy (Nickel-Titanium Naval Ordance Laboratory) by the NASA during the 1960's. This fact marked the appearance of a new class of materials, popularly known as shape memory effect alloys (SMEA). The objective of this work is to present a state-of-the-art of the development and applications for the SMEA. (E.O.)

  15. Soldering of aluminium alloys

    International Nuclear Information System (INIS)

    A literature survey about soldering in general and aluminium alloys soldering in particular is presented. The existing methods of soldering aluminium alloys are described. These include soldering with flux, soldering after preliminary plating, vacuum brazipressure and temperature (NTP), sample age calculation based on 14C half life of 5570 and 5730 years, age correction for NTP, dendrochronological corrections and the relative radiocarbon concentration. All results are given with one standard deviation. Input data test (Chauvenet's criterion), gas purity test, standard deviation test and test of the data processor are also included in the program. (author)

  16. The electrolytic plating of compositionally modulated alloys and laminated metal nano-structures based on an automated computer-controlled dual-bath system

    DEFF Research Database (Denmark)

    NabiRahni, D.M.A.; Tang, Peter Torben; Leisner, Peter

    1996-01-01

    Compositionally modulated alloys (CMAs) and laminated nano-structures of metals are attracting ever-increasing enthusiasm due to their unique mechanical, electrical and, in particular, magnetic properties when compared to those of the respective bulk metals, and as evidenced by new and fascinating....... Employing the automated dual-bath technique, multilayered composite materials of copper-nickel and copper-cobalt with more than 1000 alternating layers of varying dimensions, if desired, have been investigated and manufactured. The thickness of each sub-layer ranges from 25 nm to several micrometres (mu m...

  17. High-strength shape memory steels alloyed with nitrogen

    International Nuclear Information System (INIS)

    Since shape memory effect in Fe-Mn-Si systems was observed, increasing attention has been paid to iron based shape memory alloys due to their great technological potential. Properties of Fe-Mn-Si shape memory alloys have been improved by alloying with Cr, Ni, Co and C. A significant improvement on shape memory, mechanical and corrosion properties is attained by introducing nitrogen in Fe-Mn-Si based systems. By increasing the nitrogen content, strength of the matrix increases and the stacking fault energy decreases, which promote the formation of stress induced martensite and decrease permanent slip. The present authors have shown that nitrogen alloyed shape memory steels exhibit recoverable strains of 2.5--4.2% and recovery stresses of 330 MPa. In some cases, stresses over 700 MPa were attained at room temperature after cooling a constrained sample. Yield strengths of these steels can be as high as 1,100 MPa and tensile strengths over 1,500 MPa with elongations of 30%. In the present study, effect of nitrogen alloying on shape memory and mechanical properties of Fe-Mn-Si, Fe-Mn-Si-Cr-Ni and Fe-Mn-Cr-Ni-V alloys is studied. Nitrogen alloying is shown to exhibit a beneficial effect on shape memory properties and strength of these steels

  18. Pemilihan Bahan Alloy Untuk Konstruksi Gigitiruan

    OpenAIRE

    Medila Dahlan

    2008-01-01

    Pada kedokteran gigi bahan alloy sangat banyak digunakan dalam segala bidang. Dalam pembuatan konstruksi gigitiman biasanya digunakan alloy emas, alloy kobalt kromium, alloy nikei kromium dan alloy stainless steel sebagai komponen gigitiman kerangka logam serta pembuatan mahkota dan jembatan. Pemilihan bahan alloy dapat dilakukan berdasarkan sifat yang dimiiiki oleh masing-masing bahan alloy sehingga akan didapat hasil konstmksi gigitiruan yang memuaskan. Pada pemakaiannya didaiam mulut...

  19. Hydrogen embrittlement of vanadium alloys

    International Nuclear Information System (INIS)

    The mechanical properties of several vanadium alloys were measured with the hydrogen concentration high up to 113 mg/kg. The results showed that the alloys with low mechanical strength had better properties against hydrogen embrittlement. Oxygen in the alloy, especially that in the alloys with high strength, could enhance the hydrogen embrittlement. Mechanism analysis was given to show that the brittle fracture was mainly caused by intergranular failure. The effects of oxygen concentration and the strength of the alloy were both resulted from their contributions to the grain strength and the grain boundary strength

  20. Galvanic corrosion in odontological alloys

    International Nuclear Information System (INIS)

    Galvanic corrosion can occur when different alloys are placed in direct contact within the oral cavity or within tissues. Concern has been expressed associated with the coupling of selected restorative materials as well as implant material with various alloys used for restorative procedures. This could be critical if the crown or bridge had subgingival finish line with a metallic zone in contact with the tissue, and the implant was made in titanium alloy. The present work shows the results of galvanic coupling studies done on implants of titanium alloy connected to nickel-chromium and cobalt-chromium alloys. (Author)