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Sample records for liquid al-cu-sn alloy

  1. Enthalpies of mixing of liquid systems for lead free soldering: Al-Cu-Sn system

    Energy Technology Data Exchange (ETDEWEB)

    Flandorfer, Hans, E-mail: hans.flandorfer@univie.ac.at [University of Vienna, Department of Inorganic Chemistry/Materials Chemistry, Waehringer Str. 42, A-1090 Wien (Austria); Rechchach, Meryem; Elmahfoudi, A. [University of Vienna, Department of Inorganic Chemistry/Materials Chemistry, Waehringer Str. 42, A-1090 Wien (Austria); Faculte des Sciences, Universite Mohammed V, Laboratoire de Chimie Physique Generale, Av. Ibn Batouta, B.P. 1014, Rabat (Morocco); Bencze, Laszlo [Eoetvoes Lorand University, Dept. of Physical Chemistry, Pazmany Peter setany 1/A, H-1117 Budapest (Hungary); Popovic, Arkadij [Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Ipser, Herbert [University of Vienna, Department of Inorganic Chemistry/Materials Chemistry, Waehringer Str. 42, A-1090 Wien (Austria)

    2011-11-15

    Highlights: > First paper providing enthalpy of mixing determined by calorimetry for Al-Cu-Sn. > . > Comparative discussion of values derived from KEMS data published before. > Enthalpy of mixing at 1000 {sup o}C described for the entire ternary system Al-Cu-Sn. > New experimental enthalpy of mixing values for the binary Al-Cu system. - Abstract: The present work refers to high-temperature drop calorimetric measurements on liquid Al-Cu, Al-Sn, and Al-Cu-Sn alloys. The binary systems have been investigated at 973 K, up to 40 at.% Cu in case of Al-Cu, and over the entire concentrational range in case of Al-Sn. Measurements in the ternary Al-Cu-Sn system were performed along the following cross-sections: x{sub Al}/x{sub Cu} = 1:1, x{sub Al}/x{sub Sn} = 1:1, x{sub Cu}/x{sub Sn} = 7:3, x{sub Cu}/x{sub Sn} = 1:1, and x{sub Cu}/x{sub Sn} = 3:7 at 1273 K. Experimental data were used to find ternary interaction parameters by applying the Redlich-Kister-Muggianu model for substitutional solutions, and a full set of parameters describing the concentration dependence of the enthalpy of mixing was derived. From these, the isoenthalpy curves were constructed for 1273 K. The ternary system shows an exothermic enthalpy minimum of approx. -18,000 J/mol in the Al-Cu binary and a maximum of approx. 4000 J/mol in the Al-Sn binary system. The Al-Cu-Sn system is characterized by considerable repulsive ternary interactions as shown by the positive ternary interaction parameters.

  2. Density of Liquid Ni-Cr Alloy

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The density of liquid Ni-Cr alloy was measured by a modified sessile drop method. The density of liquid Ni-Cr alloywas found to decrease with increasing temperature and Cr concentration in the alloy. The molar volume of liquidNi-Cr alloy increases with increasing the Cr concentration in the alloy. The molar volume of Ni-Cr alloy determinedin the present work shows a positive deviation from the linear molar volume.

  3. STRUCTURE OF LIQUID CESIUM LEAD ALLOYS

    NARCIS (Netherlands)

    PRICE, DL; SABOUNGI, ML; DEWIJS, GA; VANDERLUGT, W

    1993-01-01

    Neutron diffraction measurements have been made on liquid Cs-Pb alloys at the Intense Pulsed Neutron Source. Equiatomic CsPb has been shown in previous work to be a Zintl alloy with well-defined Cs4Pb4 structural units, explaining the anomalously high electrical resistivity and specific heat observe

  4. NANOMETER SUPERSTRUCTURE IN LIQUID ALKALI THALLIUM ALLOYS

    NARCIS (Netherlands)

    XU, R; VERKERK, P; HOWELLS, WS; DEWIJS, GA; VANDERHORST, F; VANDERLUGT, W

    1993-01-01

    Structure factors obtained from neutron diffraction measurements on liquid K-Tl and Cs-Tl alloys exhibit large prepeaks at approximately 0.77 angstrom-1 and 0.70 angstrom-1, respectively. It is concluded that the liquid contains large units of thallium atoms, possibly bearing some resemblance to tho

  5. Thermodynamic and structural properties of liquid Al-Au alloys

    Science.gov (United States)

    Olajire, B. A.; Musari, A. A.

    2017-08-01

    The mixing properties of liquid Al-Au alloys with respect to the concentration of each constituent is determined using a method based on hard sphere system and pseudo-potential perturbation. These models were used to get relevant information on mixing properties of the Al-Au alloys like the Gibbs energy and the entropy of mixing. The concentration fluctuations, chemical short range order for the hard sphere mixture (quasi-lattice theory) and the activity are calculated to know the extent of order in the liquid alloys. The results revealed that there is a degree of ordering in liquid Al-Au alloy (hetero-coordinated).

  6. Liquid uranium alloy-helium fission reactor

    Science.gov (United States)

    Minkov, V.

    1984-06-13

    This invention describes a nuclear fission reactor which has a core vessel and at least one tandem heat exchanger vessel coupled therewith across upper and lower passages to define a closed flow loop. Nuclear fuel such as a uranium alloy in its liquid phase fills these vessels and flow passages. Solid control elements in the reactor core vessel are adapted to be adjusted relative to one another to control fission reaction of the liquid fuel therein. Moderator elements in the other vessel and flow passages preclude fission reaction therein. An inert gas such as helium is bubbled upwardly through the heat exchanger vessel operable to move the liquid fuel upwardly therein and unidirectionally around the closed loop and downwardly through the core vessel. This helium gas is further directed to heat conversion means outside of the reactor vessels to utilize the heat from the fission reaction to generate useful output. The nuclear fuel operates in the 1200 to 1800/sup 0/C range, and even higher to 2500/sup 0/C.

  7. Polyanions in liquid ionic alloys : A decade of research

    NARCIS (Netherlands)

    vanderLugt, W

    1996-01-01

    The occurrence of polyanions in a group of liquid ionic alloys, viz alloys of the alkali metals with 13, 14, 15 and 16 elements (post-transition-metal groups 3, 4, 5 and 6), is discussed. It is shown that there are strong parallels with the corresponding crystalline phases, in which polyanions such

  8. Thermodynamics of oxygen in dilute liquid silver-tellurium alloys.

    Science.gov (United States)

    Nyk, Justyna; Onderka, Bogusław

    The activity coefficient of oxygen [Formula: see text] in liquid Ag and binary Ag-Te dilute alloys were determined between 1,285 and 1,485 K by coulometric titration using the electrochemical cell (Ir, [O] in liquid metal or alloy | yttria stabilized zirconia | air, Pt). The experimental and evaluation procedures described in the literature were adopted. The oxygen activity coefficient was determined in pure liquid silver to be [Formula: see text]. Next, the oxygen activity coefficient in dilute Ag-(Te)-O alloys for variable XTe content (from 0.01 to 0.06) was measured. From the obtained results, Wagner's interaction parameter [Formula: see text] as a function of temperature was derived in the form [Formula: see text]. The electrochemical coulometric titration method seems to be very useful to study the thermodynamics of oxygen interaction in liquid silver and its alloys.

  9. Neutron diffraction study on liquid Al-Ni alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gruner, Sascha; Marczinke, Jennifer; Hoyer, Walter [Technische Univ. Chemnitz-Zwickau, Chemnitz (Germany). Inst. fuer Physik; Hennet, Louis [CNRS-CEMHTI, Orleans Univ. (France); Cuello, Gabriel Julio [Institute Laue - Langevin, Grenoble (France); Basque Country Univ., Bilbao (Spain)

    2010-06-15

    A neutron diffraction study on liquid Al-Ni alloys close to the liquidus temperature is presented. By applying an aerodynamic levitation technique associated with CO{sub 2} laser heating, it was possible to investigate the high-melting alloys around the equi-atomic composition, too. We observe a change in the local chemical atomic arrangement from preferred environing of like atoms in Al-rich alloys to hetero-coordination in the Ni-rich alloys. It is furthermore demonstrated that the apparent pre-peak can be attributed to a distinct Ni-Ni short-range order. (orig.)

  10. Density of Ni-Al Alloys in Liquid and Solid-Liquid Coexistence State Measured by a Modified Pycnometric Method

    Institute of Scientific and Technical Information of China (English)

    Liang FANG; Feng XIAO; Zushu LI; Zainan TAO

    2004-01-01

    The density of Ni-Al alloys in both liquid state and solid-liquid coexistence state was measured with a modified pycnometric method. It was found that the density of NI-Al alloys decreases with increasing temperature and Al concentration in the alloys. The molar volume of liquid Ni-Al binary alloys increases with the increase of temperature and Al concentration. The partial molar volume of Al in NI-Al binary alloy was calculated approximately. The molar volume of liquid NI-Al alloy determined in the present work shows a negative deviation from the ideal linear molar volume.

  11. Isothermal corrosion Fe3Si alloy in liquid zinc

    Institute of Scientific and Technical Information of China (English)

    Wen jun Wang; Junping Lin; Yanli Wang; Guoliang Chen

    2007-01-01

    The isothermal corrosion testing,microscopic examination and the performance of Fe3Si alloy as materials of construction for bath hardware in continuous hot-dipping lines were studied.The corrosion of Fe3Si alloy in molten zinc was controlled by attacking the grain boundaries preferentially.Aluminum reacted with iron of Fe3Si alloy firstly while the samples were immersed in molten zinc,although aluminum contents in the molten zinc were very low.The phase of reaction product was thought to be Fe2Al5.The corrosion rate of the Fe3Si alloy in molten zinc was determined to be approximately 2.9×10-3 mm/h,therefore the liquid zinc corrosion resistance of Fe3Si alloy was very weak.

  12. Cleavage crystallography of liquid metal embrittled aluminum alloys

    Science.gov (United States)

    Reynolds, A. P.; Stoner, G. E.

    1991-01-01

    The crystallography of liquid metal-induced transgranular cleavage in six aluminum alloys having a variety of microstructures has been determined via Laue X-ray back reflection. The cleavage crystallography was independent of alloy microstructure, and the cleavage plane was 100-plane oriented in all cases. It was further determined that the cleavage crystallography was not influenced by alloy texture. Examination of the fracture surface indicated that there was not a unique direction of crack propagation. In addition, the existence of 100-plane cleavage on alloy 2024 fracture surfaces was inferred by comparison of secondary cleavage crack intersection geometry on the 2024 surfaces with the geometry of secondary cleavage crack intersections on the test alloys.

  13. Thermodynamic Properties of Liquid Ag-Bi-Sn Alloys

    Science.gov (United States)

    Li, Zuoan; Knott, Sabine; Mikula, Adolf

    2007-01-01

    As a promising lead-free solder, the thermodynamic properties of the liquid ternary Ag-Bi-Sn system were investigated. Using an appropriate galvanic cell, the partial free energies of Sn in liquid Ag-Bi-Sn alloys were determined as a function of concentration and temperature. Thermodynamic properties were obtained for 27 alloys. Their composition was situated on three cross sections with the constant ratios of Ag:Bi = 2:1, 1:1, and 1:2. The integral Gibbs free energy and the integral enthalpy for the ternary system at 900 K were calculated by Gibbs Duhem integration.

  14. Liquid phase surface alloying of AZ91D magnesium alloy with Al and Ni powders

    Energy Technology Data Exchange (ETDEWEB)

    Elahi, Mohammad Reza, E-mail: m.r_elahi@alumni.ut.ac.ir [School of Metallurgy and Materials, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Sohi, Mahmoud Heydarzadeh; Safaei, Abdolghayoom [School of Metallurgy and Materials, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)

    2012-05-15

    In this paper, liquid phase surface alloying of AZ91D magnesium alloy was carried out by pre-placing of Al and Ni powder mixture and subsequent tungsten inert gas (TIG) melting process. The effects of TIG processing parameters on both microstructures and resulting hardness were investigated. Microstructures of alloyed layers were studied by optical microscope, and scanning electron microscope equipped with energy dispersive X-ray spectroscopy (EDS) analyzer, and the phases were identified by X-ray diffraction analysis. The microhardness of the surface alloyed layer was also measured. The surface hardness was increased from 80 HV{sub 0.1} for AZ91D magnesium alloy to as high as 162 HV{sub 0.1} for alloyed sample due to the formation of Mg{sub 17}Al{sub 12} and AlNi{sub 3} intermetallic compounds in the alloyed region and structural refinement. Hardness improvement reduced the wear rate of the surface alloyed layer to almost half of that of the untreated substrate.

  15. Density Measurement of Liquid Ni-Ta Alloys by a Modified Sessile Drop Method

    Institute of Scientific and Technical Information of China (English)

    FANG Liang; XIAO Feng; TAO Zainan; Kusuhiro Mukai

    2005-01-01

    The density of liquid Ni-Ta alloys was measured by using a modified sessile drop method. It is found that the density of the liquid Ni-Ta alloys decreases with the increasing temperature, but increases with the increase of tantalum concentration in the alloys. The molar volume of liquid Ni-Ta binary alloys increases with the increase of temperature and tantalum concentration.

  16. Thermodynamic and structural properties of Bi-based liquid alloys

    Science.gov (United States)

    Yadav, S. K.; Jha, L. N.; Adhikari, D.

    2015-10-01

    Thermodynamic and microscopic structural properties of two Bi-based liquid alloys, such as In-Bi at 900 K and Tl-Bi at 750 K have been studied employing the regular associated solution model. We have estimated the mole fractions of the complexes and the free monomers assuming the existence of complexes In2 Bi in In-Bi melt and TlBi in Tl-Bi melt. The thermodynamic properties have been studied by computing the Gibbs free energy of mixing, enthalpy of mixing, entropy of mixing and activities of the monomers. The compositional contributions of the heat associated with the formation of complexes and the heat of mixing of the monomers to the net enthalpy change has also been studied. The structural properties of the liquid alloys have been studied by computing concentration fluctuation in the long-wavelength limit, chemical short-range order parameter and the ratio of mutual to intrinsic diffusion coefficients. For both of the alloy systems, the theoretical as well as the experimental values of SCC (0) are found to be lower than the corresponding ideal values over the whole composition range, indicating the hetero-coordinating nature of Bi-In and Bi-Tl alloy melts. All the interaction energy parameters are found to be negative and temperature dependent, and both the alloy systems are found to be weakly interacting.

  17. Injectable liquid alkali alloy based-tumor thermal ablation therapy.

    Science.gov (United States)

    Rao, Wei; Liu, Jing

    2009-01-01

    The alkali metal was recently found to be a very useful agent for inducing minimally invasive tumor hyperthermia therapy. However, the solid-like metal makes it somewhat inconvenient to perform the surgery. Here, to overcome this drawback, the NaK alloy in liquid state at room temperature was proposed as a highly efficient thermal ablative agent for tumor treatment. For illustration purposes, the functionalized liquid NaK alloy at a mass ratio 1:1 was obtained and an amount of 0.35 ml was injected into in vitro pork. The sizes of the damage region and temperature response were measured. It was found that significant temperature increase by a magnitude of > 80 degrees C can easily be obtained. This produced a large coagulation and necrotic area within selected areas for in vitro tests and the necrotic region volume is three times that of the NaK injection quantity. Furthermore, for the in vivo experiment, breast EMT6 tumor in mouse was subjected to treatment by NaK alloy. Tumor was harvested after the experiment to assess its viability. Histological section showed complete necrosis at the target site. These conceptual results demonstrate that using injectable liquid alkali alloy to ablate tumor is rather promising. This study also raised interesting issues waiting for clarification in future technical and animal studies aiming to assess efficacy, side effects and safety of the new therapy.

  18. Structural studies of liquid Co–Sn alloys

    Science.gov (United States)

    Yakymovych, A.; Shtablavyi, I.; Mudry, S.

    2014-01-01

    An analysis of the structure features of liquid Co–Sn alloys has been performed by means of X-ray diffraction method, viscosity coefficient analysis and computer simulation method. The X-ray diffraction investigations were carried out over a wide concentration range at the temperature 1473 K. It was found that the structure of these alloys can be described in the frame of independent X-ray scattering model. The viscosity coefficient was calculated by an excess entropy scaling and compared with experimental data. PMID:25328282

  19. Structural studies of liquid Co-Sn alloys.

    Science.gov (United States)

    Yakymovych, A; Shtablavyi, I; Mudry, S

    2014-10-15

    An analysis of the structure features of liquid Co-Sn alloys has been performed by means of X-ray diffraction method, viscosity coefficient analysis and computer simulation method. The X-ray diffraction investigations were carried out over a wide concentration range at the temperature 1473 K. It was found that the structure of these alloys can be described in the frame of independent X-ray scattering model. The viscosity coefficient was calculated by an excess entropy scaling and compared with experimental data.

  20. Studying Cu Alloy Corrosion Products in Cooling Liquid

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The effect of cooiing liquid used for heat exchangers on the Cu alloy corrosion products has been examined using potential-time measurements under applied current condition (anodizing), potentiodynamic polarization, X-ray diffraction (XRD) and infrared spectroscopy (IR). The corrosion products formed on the Cu alloy surface during anodizing, are Cu2O, Cu2(OH)3CI, and Cu2S. NaCI is detected in the corrosion products. The film formation depends on the applied current and the shift of potential to nobler direction indicates its formation progress.

  1. TOPICAL REVIEW On the glass forming ability of liquid alloys

    Directory of Open Access Journals (Sweden)

    Yoshio Waseda et al

    2008-01-01

    Full Text Available By using the concepts of the short-range order (SRO and middle-range order (MRO characterizing structures, an attempt has been made to describe the glass forming ability (GFA of liquid alloys. This includes the effect of more than two kinds of SRO in the liquid caused by the addition of second and third elements to a metallic solvent. The minimum solute concentration is related to the atomic volume mismatch estimated from the cube of the atomic radius. The optimum solute concentration for good glass formability in several binary and some ternary alloys is discussed on the basis of the empirical guideline. A new approach to obtaining good GFA of liquid alloys is based on four main factors: (i formation of new SRO and coexistence of two or more kinds of SRO, (ii stabilization of dense random packing structure by restraining the atomic redistribution for initiating the nucleation and growth process, (iii formation of a stable cluster (SC or the MRO by the harmonious coupling of SROs, and (iv difference between SRO characterizing the liquid structure and the near-neighbor environment in the corresponding equilibrium crystalline phases. The use of interaction parameters, widely used in the thermodynamics of multicomponent metallic solutions, is proposed for effectively selecting the third solute element (X3 for enhancing the GFA of a metallic liquid (M containing the second solute (X2. Fe70-B20-(X310 alloys (X3=Cr, W, Nb, Zr and Hf are used for illustration. Two typical model structures denoted by the Bernal and chemical-order types are used in describing the new glass structure as a function of solute concentration.

  2. Electric field fluctuations in liquid tellurium alloys a hint to bond character

    NARCIS (Netherlands)

    Paulick, C.A.; Brinkmann, R.; Elwenspoek, Michael Curt; von Hartrott, M.; Kiehl, M.; Maxim, P.; Quitmann, D.

    1985-01-01

    Atomic scale electric field fluctuations in liquid tellurium alloys are detected as they induce nuclear spin relaxation rate RQ in noble gas impurity atoms, via quadrupolar interaction. Results for Xe in liquid Ag, Ga, In, Tl, Ge, Sn---Te alloys are discussed, assuming that bonding in these alloys

  3. Decomposition mechanism in supercooled liquid alloys.

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, W. L.; Loffler, J. F.; Thiyagarajan, P.

    1999-07-12

    The authors performed small-angle neutron scattering experiments on the bulk amorphous alloy Zr{sub 41.2}Ti{sub 13.8}Cu{sub 12.5}Ni{sub 10}Be{sub 22.5} (Vit1{reg_sign}) and on further alloys, where the ZrTi and CuBe content have been changed, following the tie-line in the direction of Zr{sub 46.8}Ti{sub 8.2}Cu{sub 7.5}Ni{sub 10}Be{sub 27.5} (Vit4{reg_sign}). The SANS data of the samples, preannealed at temperatures between 330 C and 390 C, show interference peaks giving evidence for spatially correlated arrangements of inhomogeneities. The Q values of the interference peaks, Q{sub max}, decrease with increasing annealing temperature T{sub a} and, at a given annealing temperature, with composition following the tie-line from Vit1 to Vit4. They find that, in two distinguished regimes, the data follow a relation 1/L{sup 2} {proportional_to} T{sub a} as predicted by Cahn's theory (L = 2{pi}/Q{sub max} is the wavelength of the decomposition), with a crossover at the glass transition temperature T{sub g} = 350 C. The authors explain the crossover by different diffusion mechanisms below and above T{sub g}.

  4. Experimental and calculated liquid-liquid interfacial tension in demixing metal alloys

    Institute of Scientific and Technical Information of China (English)

    Walter Hoyer; Ivan Kaban

    2006-01-01

    Liquid-liquid interfacial tension in binary and ternary Al-based monotectic systems has been determined experimentally with a tensiometric method in a wide temperature interval. The temperature dependence of the interfacial tension is well described by a power law function of the type σαβ~ (1 - T/Tc)δ with the critical exponent δ = 1.3 and a critical tem perature TC. Theoretical models describing the liquid-liquid interface in monotectic alloys and their applicability for calculation of the interfacial tension and its temperature dependence in binary systems are considered.

  5. Effect of Brownian Coagulation on the Liquid-liquid Decomposition in Gas-atomized Alloy Drops

    Institute of Scientific and Technical Information of China (English)

    Jiuzhou ZHAO; Lingling GAO; Jie HE; L.Ratke

    2006-01-01

    Modeling and simulation have been carried out for Al-Pb alloys to investigate the Brownian coagulation effect on the microstructure development in a gas-atomized drop during the liquid-liquid decomposition.The results indicate that Brownian coagulation has a weak effect on the nucleation and a relatively strong effect on coarsening the minority phase droplets. The influence of Brownian coagulation on the liquid-liquid decomposition decreases with the increase in the diameter (or the decrease in the cooling rate) of the atomized drop.

  6. Fatigue Resistance of Liquid-assisted Self-repairing Aluminum Alloys Reinforced with Shape Memory Alloys

    Science.gov (United States)

    Wright, M. Clara; Manuel, Michele; Wallace, Terryl

    2013-01-01

    A self-repairing aluminum-based composite system has been developed using a liquid-assisted healing theory in conjunction with the shape memory effect of wire reinforcements. The metal-metal composite was thermodynamically designed to have a matrix with a relatively even dispersion of a low-melting eutectic phase, allowing for repair of cracks at a predetermined temperature. Additionally, shape memory alloy (SMA) wire reinforcements were used within the composite to provide crack closure. Investigators focused the research on fatigue cracks propagating through the matrix in order to show a proof-of-concept Shape Memory Alloy Self-Healing (SMASH) technology for aeronautical applications.

  7. Surface properties of liquid In-Zn alloys

    Science.gov (United States)

    Pstruś, J.; Moser, Z.; Gąsior, W.

    2011-02-01

    The measurements of surface tension and density of zinc, indium and liquid In-Zn alloys containing 0.9, 0.85, 0.75, 0.70, 0.60, 0.40, 0.25 and 0.10 mole fraction of In were carried out using the method of maximum pressure in gaseous bubbles (MBP) as well as dilatometric technique. The technique of sessile drop was additionally applied in the measurements of surface tension for pure indium and zinc. The measurements were performed at temperature range 474-1151 K. The isotherms of surface tension calculated based on Butler's equation at 700 and 1100 K corresponded well with the experimental values for zinc content lower than 0.6 mole fraction. The surface tension calculated for alloys of higher zinc concentrations (0.6 < XZn < 0.95) had a positive value of the surface tension temperature coefficient (dσ/dT), which did not coincide with the experimental results. The density as well as molar volume of liquid In-Zn alloys showed almost identical behaviour like the ideal solutions. The observed little deviations were contained within assessed experimental errors.

  8. Surface properties of liquid In-Zn alloys

    Energy Technology Data Exchange (ETDEWEB)

    Pstrus, J., E-mail: nmpstrus@imim-pan.krakow.pl [Institute of Metallurgy and Materials Science, Polish Academy of Sciences, 25 Reymonta Str., 30-059 Krakow (Poland); Moser, Z.; Gasior, W. [Institute of Metallurgy and Materials Science, Polish Academy of Sciences, 25 Reymonta Str., 30-059 Krakow (Poland)

    2011-02-15

    The measurements of surface tension and density of zinc, indium and liquid In-Zn alloys containing 0.9, 0.85, 0.75, 0.70, 0.60, 0.40, 0.25 and 0.10 mole fraction of In were carried out using the method of maximum pressure in gaseous bubbles (MBP) as well as dilatometric technique. The technique of sessile drop was additionally applied in the measurements of surface tension for pure indium and zinc. The measurements were performed at temperature range 474-1151 K. The isotherms of surface tension calculated based on Butler's equation at 700 and 1100 K corresponded well with the experimental values for zinc content lower than 0.6 mole fraction. The surface tension calculated for alloys of higher zinc concentrations (0.6 < X{sub Zn} < 0.95) had a positive value of the surface tension temperature coefficient (d{sigma}/dT), which did not coincide with the experimental results. The density as well as molar volume of liquid In-Zn alloys showed almost identical behaviour like the ideal solutions. The observed little deviations were contained within assessed experimental errors.

  9. Concentration dependent structural parameters of liquid Al-Fe alloys

    Science.gov (United States)

    Lalnuntluanga, C.; Mishra, Raj Kumar

    2016-10-01

    Square well potential is perturbed over Lebowtiz solution of hard sphere mixtures to determine direct correlation function,C(0) ij(r) in repulsive and attractive regions under Mean Spherical Model Approximation [1]. Obtained direct correlation functions were employed to derive partial structure factors and then total structure factor, S(k) in liquid Al-Fe alloy at different atomic percent of Al. Fourier transform of partial and total structure factors gives partial and total radial distribution functions, g(r) from which partial and total coordination numbers and the partial nearest-neighbor distances were computed.

  10. Density of liquid NiCoAlCr quarternary alloys measured by modified sessile drop method

    Institute of Scientific and Technical Information of China (English)

    FANG Liang; ZHANG Shu-fang; XIAO Feng; YANG Ling-chuan; DONG Jian-xin; CAO Chun-lan; TAO Zai-nan; K. MUKAI

    2006-01-01

    The densities of liquid NiCoAlCr quaternary alloys with a fixed molar ratio of Ni to Co to Al (x(Ni)-x(Co)-x(Al)≈73-12-15) which is close to the average value of the commercial Ni-based superalloys TMS75, INCO713, CM247LC and CMSX-4, and the mass fraction of chromium changes from 0 to 9% were measured by a modified sessile drop method. It is found that with increasing temperature and chromium concentration in the alloys, the densities of the liquid NiCoAlCr quaternary alloys decrease, whereas the molar volume of the liquid NiCoAlCr quaternary alloys increases. And the liquid densities of NiCoAlCr quaternary alloys calculated from the partial molar volumes of nickel, cobalt, aluminum and chromium in the corresponding Ni-bases binary alloys are in good agreement with the experimental ones, i.e. within the error tolerance range the densities of the liquid Ni-based multi-component alloys can be predicted from the partial volumes of elements in Ni-based binary alloys in liquid state. The molar volume of liquid NiCoAlCr binary alloy shows a negative deviation from the ideal linear mixing and the deviation changes small with the increase of chromium concentration at the same temperature.

  11. Mechanisms of pressure filtration of liquid aluminum alloys

    Science.gov (United States)

    Cao, X.

    2006-12-01

    The Prefil Footprinter, a portable pressure filtration instrument, is usually used to detect the quality of liquid aluminum alloys. However, no investigations have ever been done to calculate the cake resistance to date. Based on the identification and classification of flow behavior using the first derivative method for filtrate mass vs filtration time curves, conventional filtration equations are successfully employed to understand the filtration behaviors. From the analyses of the variations of cake resistance with filtration time, the filtration mechanisms are discussed in detail over the different filtration stages. During the steady stage, either incompressible or compressible cake mode is the main mechanism. At the initial and terminal transient stages, however, deep-bed filtration, complete straining, and solidification clogging may appear. Solid inclusions in liquid metal have significant influence on the cake structures and properties. Some important issues related to the heterogeneity of filter media and test methodology are highlighted in this work.

  12. Liquid Phase Sintering of Highly Alloyed Stainless Steel

    DEFF Research Database (Denmark)

    Mathiesen, Troels

    1996-01-01

    Liquid phase sintering of stainless steel is usually applied to improve corrosion resistance by obtaining a material without an open pore system. The dense structure normally also give a higher strength when compared to conventional sintered steel. Liquid phase sintrering based on addition...... of boride to AISI 316L type steels have previously been studied, but were found to be sensitive to intergranular corrosion due to formation of intermetallic phases rich in chromium and molybdenum. In order to improve this system further, new investigations have focused on the use of higher alloyed stainless...... steel as base material. The stainless base powders were added different amounts and types of boride and sintered in hydrogen at different temperatures and times in a laboratory furnace. During sintering the outlet gas was analyzed and subsequently related to the obtained microstructure. Thermodynamic...

  13. Nuclear magnetic resonance studies of liquid metal alloys

    Science.gov (United States)

    Quitmann, D.

    1990-12-01

    The Knight shift K and quadrupolar relaxation rate Rq in liquid metallic systems, in which effects of bonding become increasingly prominent, are surveyed. In Rb, a theoretical calculation of Rq, including mode-coupling theory for the liquid, and the r-dependent Sternheimer factor, predicted closely the recent experimental redetermination. In Ge and in Cu-Ge and similar nearly free-electron systems, the quantitative analysis of K still poses problems, while qualitatively K(x) displays clearly a correspondence to the resistivity maximum. In metallic alloys with compound forming tendency, models based on an association (A+B from or to AB) connect K and Rq quantitatively with the heat of mixing, but the microscopic foundation of the association ansatz is uncertain.

  14. THE ELECTROCONDUCTIVITY OF THE LIQUID ALLOYS OF TRANSITION METALS

    Directory of Open Access Journals (Sweden)

    V.T.Shvets

    2004-01-01

    Full Text Available The concentration dependance of electroresistivity of the liquid binary alloys of transition metals Fe, Co and Ni is calculated. We considered the contribution to conductivity from the s-electrons, described within the model of nearly free electrons. The role of the partially occupied d-bands is reduced to resonance scattering of the s-electrons on d-states. The interaction of the s- and d-electrons is described by the hybridization potential of s- and d-states. The interaction with the ions, not including the partially occupied d-states, is described using the pseudopotential of the electron-ion interaction. The electroresistivity of the alloys is calculated in the second order of the perturbation theory in pseudopotential and hybridization potential. The concentration dependance of electroresistivity of the binary alloys approaches the linear regime as the resonance scattering of the s-electrons on d-states prevails over the scattering on the ions. The calculations exhibit good agreement with the experimental data.

  15. Thermodynamics and surface properties of liquid Al-Ga and Al-Ge alloys

    Energy Technology Data Exchange (ETDEWEB)

    Anusionwu, B.C. [Abdus Salam Int. Centre for Theoretical Physics, Trieste (Italy); Federal University of Technology, Department of Physics, Owerri (Nigeria); Adebayo, G.A. [Abdus Salam Int. Centre for Theoretical Physics, Trieste (Italy); University of Agriculture, Department of Physics, Abeokuta (Nigeria); Madu, C.A. [Federal University of Technology, Department of Physics, Owerri (Nigeria)

    2009-11-15

    The surface properties of Al-Ga and Al-Ge liquid alloys have been theoretically investigated at a temperature of 1100 K and 1220 K respectively. For the Al-Ga system, the quasi chemical model for regular alloy and a model for phase segregating alloy systems were applied, while for the Al-Ge system the quasi chemical model for regular and compound forming binary alloys were applied. In the case of Al-Ga, the models for the regular alloys and that for the phase segregating alloys produced the same value of order energy and same values of thermodynamic and surface properties, while for the Al-Ge system, the model for the regular alloy reproduced better the thermodynamic properties of the alloy. The model for the compound forming systems showed a qualitative trend with the measured values of the thermodynamic properties of the Al-Ge alloy and suggests the presence of a weak complex of the form Al{sub 2}Ge{sub 3}. The surface concentrations for the alloys show that Ga manifests some level of surface segregation in Al-Ga liquid alloy while the surface concentration of Ge in Al-Ge liquid alloy showed a near Roultian behavior below 0.8 atomic fraction of Ge. (orig.)

  16. Thermodynamics and surface properties of liquid Al-Ga and Al-Ge alloys

    Science.gov (United States)

    Anusionwu, B. C.; Adebayo, G. A.; Madu, C. A.

    2009-11-01

    The surface properties of Al-Ga and Al-Ge liquid alloys have been theoretically investigated at a temperature of 1100 K and 1220 K respectively. For the Al-Ga system, the quasi chemical model for regular alloy and a model for phase segregating alloy systems were applied, while for the Al-Ge system the quasi chemical model for regular and compound forming binary alloys were applied. In the case of Al-Ga, the models for the regular alloys and that for the phase segregating alloys produced the same value of order energy and same values of thermodynamic and surface properties, while for the Al-Ge system, the model for the regular alloy reproduced better the thermodynamic properties of the alloy. The model for the compound forming systems showed a qualitative trend with the measured values of the thermodynamic properties of the Al-Ge alloy and suggests the presence of a weak complex of the form Al2Ge3. The surface concentrations for the alloys show that Ga manifests some level of surface segregation in Al-Ga liquid alloy while the surface concentration of Ge in Al-Ge liquid alloy showed a near Roultian behavior below 0.8 atomic fraction of Ge.

  17. Density of Liquid Ni-Mo Alloys Measured by a Modified Sessile Drop Method

    Institute of Scientific and Technical Information of China (English)

    Liang FANG; Zushu LI; ZaiNan TAO; Feng XIAO

    2004-01-01

    The density of liquid binary Ni-Mo alloys with molybdenum concentration from 0 to 20% (mass fraction) was measured by a modified sessile drop method. It has been found that the density of the liquid Ni-Mo alloys decreases with increasing temperature, but increases with the increase of molybdenum concentration in the alloys. The molar volume of liquid Ni-Mo binary alloys increases with the increase of temperature and molybdenum concentration. The partial molar volume of molybdenum in Ni-Mo binary alloy has been approximately calculated as [13.18 - 2.65 × 10-3T + (-47.94 + 3.10 × 10-2T) × 10-2XMo] × 10-6m3·mol-1. The molar volume of Ni-Mo alloy determined in the present work shows a negative deviation from the ideal linear mixing molar volume.

  18. Study on Liquid Structure of Iron-Rich Fe-Si Alloy

    Institute of Scientific and Technical Information of China (English)

    TENG Xin-ying; LIU Han-lian; WANG Huan-rong; YE Yi-fu

    2003-01-01

    The liquid structure of iron-rich Fe-Si alloys (the silicon content is 22, 32, 34, 50 at%, respectively) was studied by high temperature θ-θ diffractometer at 1 550 ℃. The results show that the coordination number of atoms decreases with increasing silicon content. A visible pre-peak was observed in the structure factor of Fe-Si alloys, especially for the liquid Fe78Si22 and Fe68Si32 alloys. The special study was given on the liquid structure of Fe68Si32 alloy at temperature from 1 250 to 1 550 ℃. A distinct pre-peak was found at scattering vector Q=15.5 nm-1 in the structure factor. That means there are ordered D03 structure clusters in the liquid Fe68Si32 alloy. The correlation between silicon atoms in the Fe3Si compounds leads to the pre-peak in the structure factor.

  19. Dendrite growth characteristics within liquid Fe-Sb alloy

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Bulk samples and small droplets of liquid Fe-10%Sb alloys are undercooled up to 429 K (0.24TL) and 568 K (0.32TL), respectively, with glass fluxing and free fall techniques. The high undercooling does not change the phase constitution, and only the αFe solid solution is found in the rapidly solidified alloy. The experimental results show that when the undercooling is below 296 K, the growth velocity of αFe dendrite rises exponentially with the increase of undercooling and reaches a maximum value 1.38 m/s. Subsequently, the growth velocity begins to decrease if undercooling further increases. The αFe phase grows into coarse dendrites under small undercooling conditions, whereas it becomes vermicular dendrites in highly undercooled melts. The solute trapping is closely related to the dendrite growth velocity and cooling rate rather than undercooling. Although the solute trapping can be remarkably suppressed by the rapid dendrite growth, the segregationless solidification is not observed in the present experiments due to the large solidification temperature range.

  20. Dendrite growth characteristics within liquid Fe-Sb alloy

    Institute of Scientific and Technical Information of China (English)

    WANG WeiLi; Lü YongJun; QIN HaiYan; WEI BingBo

    2009-01-01

    Bulk samples and small droplets of liquid Fe-10%Sb alloys are undercooled up to 429 K (0.24TL) and 568 K (0.32 TL), respectively, with glass fluxing and free fall techniques. The high undercooling does not change the phase constitution, and only the αFe solid solution is found in the rapidly solidified alloy.The experimental results show that when the undercooling is below 296 K, the growth velocity of αFe dendrite rises exponentially with the increase of undercooling and reaches a maximum value 1.38 m/s.Subsequently, the growth velocity begins to decrease if undercooling further increases. The αFe phase grows into coarse dendrites under small undercooling conditions, whereas it becomes vermicular dendrites in highly undercooled melts. The solute trapping is closely related to the dendrite growth velocity and cooling rate rather than undercooling. Although the solute trapping can be remarkably suppressed by the rapid dendrite growth, the segregationless solidification is not observed in the present experiments due to the large solidification temperature range.

  1. Thermophysical Properties of Liquid AlTi-Based Alloys

    Science.gov (United States)

    Egry, I.; Holland-Moritz, D.; Novakovic, R.; Ricci, E.; Wunderlich, R.; Sobczak, N.

    2010-05-01

    The surface tension and density of three liquid AlTi-based alloys (AlTiV, AlTiNb, and AlTiTa) have been measured using electromagnetic levitation as a tool for containerless processing. Surface tension has been determined by the oscillating-drop method, while the density was measured using a shadowgraph technique. Both quantities were determined over a wide temperature range, including the undercooled regime. In addition, sessile-drop and pendant-drop experiments to determine the surface tension were performed in a recently built high-temperature furnace. The measured data were compared to thermodynamic calculations using phenomenological models and the Butler equation. Generally, good agreement was found.

  2. Effect of electric field on the activity and quenching structure of liquid Cu-Al alloys

    Institute of Scientific and Technical Information of China (English)

    Fajun Guo; Lingzhen Li; Yanbing Zong; Daqiang Cang; Wen Pan; Jun Zhang

    2005-01-01

    The activity coefficient of Al in molten Cu decreases with the increasing of electric current applied to the liquid alloy of Cu-0.2wt%Al. To investigate the mechanism, the quenching experimental results of the liquid Al-Cu alloy show that there is a remarkable change in structure, in which the solute congregates along the current direction especially for DC current. The mechanism of the activity coefficient change of Al in molten Cu-0.2wt%Al alloy treated by electrical field was discussed. Further, the results also provide an evidence for the short-range-ordered liquid metal.

  3. Thermodynamic and surface properties of Sb-Sn and In-Sn liquid alloys

    Indian Academy of Sciences (India)

    B C Anusionwu

    2006-08-01

    The thermodynamic properties of Sb-Sn and In-Sn liquid alloys have been studied using the quasi-chemical model for compound forming binary alloys and that for simple regular alloys. The concentration fluctuation cc(0) and the Warren-Cowley short-range order parameter (1) were determined for the whole concentration range at a temperature of 770 K. The surface tensions of these liquid alloys were determined for the whole concentration range by using energetics determined from thermodynamic calculations. In all calculations, In{Sn manifested properties very close to alloys of ideal mixing, while Sb-Sn showed properties that are asymmetric about equiatomic composition. Our results suggest that a weak complex of the form SbSn2 could be present in the Sb-Sn alloy at a temperature of about 770 K.

  4. Effect of Cerium on the Viscosity of Liquid Fe-C Alloy of Eutectic Content

    Institute of Scientific and Technical Information of China (English)

    滕新营; 叶以富; 刘含莲; 王焕荣; 石志强; 耿浩然

    2002-01-01

    The viscosities of liquid Fe-4.30C and Fe-4.30C-Ce alloys were measured by oscillating crucible viscometer. The results show that viscosity of Fe-4.30C alloy changes from 5.50 to 8.30 MPa*s when the liquid is cooled from 1425 ℃ to the melting point. The abnormity of viscosity of Fe-4.30C alloy near the melting point is reasonable due to the formation of graphite. The addition of cerium especially with content higher than 0.21% causes an evidently decrease in viscosity for eutectic alloy resulting from increase of free volume and size decrease of atom cluster in the liquids. It can be concended that the existence of C-Ce compound contributes to the discontinuous of viscosity at 1340~1370 ℃ for the Fe-4.30C-Ce alloy by experinments with differential scanning calorimeter.

  5. Correlation Between Superheated Liquid Fragility And Onset Temperature Of Crystallization For Al-Based Amorphous Alloys

    Directory of Open Access Journals (Sweden)

    Guo J.

    2015-06-01

    Full Text Available Amorphous alloys or metallic glasses have attracted significant interest in the materials science and engineering communities due to their unique physical, mechanical, and chemical properties. The viscous flow of amorphous alloys exhibiting high strain rate sensitivity and homogeneous deformation is considered to be an important characteristic in thermoplastic forming processes performed within the supercooled liquid region because it allows superplastic-like deformation behavior. Here, the correlation between the superheated liquid fragility, and the onset temperature of crystallization for Al-based alloys, is investigated. The activation energy for viscous flow of the liquid is also investigated. There is a negative correlation between the parameter of superheated liquid fragility and the onset temperature of crystallization in the same Al-based alloy system. The activation energy decreases as the onset temperature of crystallization increases. This indicates that the stability of a superheated liquid can affect the thermal stability of the amorphous alloy. It also means that a liquid with a large superheated liquid fragility, when rapidly solidified, forms an amorphous alloy with a low thermal stability.

  6. Electrical resistivity of NaPb compound-forming liquid alloy using ab initio pseudopotentials

    Indian Academy of Sciences (India)

    Anil Thakur; N S Negi; P K Ahluwalla

    2005-08-01

    The study of electrical resistivity of compound-forming liquid alloy, NaPb, is presented as a function of concentration. Hard sphere diameters of Na and Pb are obtained through the interionic pair potentials evaluated using Troullier and Martins ab initio pseudopotential, which have been used to calculate the partial structure factors (). Considering the liquid alloy to be a ternary mixture, Ziman formula, modified for complex formation has been used for calculating resistivity of binary liquid alloys. Form factors are calculated using ab initio pseudopotentials. The results suggest that Ziman formalism, when used with ab initio pseudopotentials, are quite successful in explaining the electrical resistivity data of compound-forming binary liquid alloys.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-09-23

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

  8. Magnetic susceptibilities of liquid Cr-Au, Mn-Au and Fe-Au alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ohno, S.; Shimakura, H. [Niigata University of Pharmacy and Applied Life Sciences, Higashijima, Akiha-ku, Niigata 956-8603 (Japan); Tahara, S. [Faculty of Science, University of the Ryukyus, Nishihara-cho, Okinawa 903-0213 (Japan); Okada, T. [Niigata College of Technology, Kamishin’eicho, Nishi-ku, Niigata 950-2076 (Japan)

    2015-08-17

    The magnetic susceptibility of liquid Cr-Au, Mn-Au, Fe-Au and Cu-Au alloys was investigated as a function of temperature and composition. Liquid Cr{sub 1-c}Au{sub c} with 0.5 ≤ c and Mn{sub 1-c}Au{sub c} with 0.3≤c obeyed the Curie-Weiss law with regard to their dependence of χ on temperature. The magnetic susceptibilities of liquid Fe-Au alloys also exhibited Curie-Weiss behavior with a reasonable value for the effective number of Bohr magneton. On the Au-rich side, the composition dependence of χ for liquid TM-Au (TM=Cr, Mn, Fe) alloys increased rapidly with increasing TM content, respectively. Additionally, the composition dependences of χ for liquid Cr-Au, Mn-Au, and Fe-Au alloys had maxima at compositions of 50 at% Cr, 70 at% Mn, and 85 at% Fe, respectively. We compared the composition dependences of χ{sub 3d} due to 3d electrons for liquid binary TM-M (M=Au, Al, Si, Sb), and investigated the relationship between χ{sub 3d} and E{sub F} in liquid binary TM-M alloys at a composition of 50 at% TM.

  9. Characterization of constitutional liquid film migration in nickel-base alloy 718

    Science.gov (United States)

    Acoff, V. L.; Thompson, R. G.

    1996-09-01

    When multiphase alloys are rapidly heated, it is possible to cause melting of the interface between phases. This is called constitutional liquation if, during melting, the bulk composition is in a nonliquid region of the phase diagram but the tie-line between the liquating phases passes through a liquid region. The liquid produced during constitutional liquation can spread along grain boundaries and promote liquid film migration (LFM). This is known as constitutional liquid film migration (CLFM), which is thermodynamically similar to liquid film migration; however, mechanistically there are significant differences. Nickel-base alloy 718 has been studied to show the features of migration that are unique to CLFM. Experimentation consisted of heat-treating rods of alloy 718 to promote the trapping of niobium carbide particles on the grain boundaries. These samples were then subjected to isothermal treatments above their constitutional-liquation temperature, which produced CLFM of the grain boundaries. The movement of the liquid films away from their centers of curvature, the formation of a new solid solution behind the migrated liquid films, and the reversals of curvature of the migrated liquid films confirmed that CLFM was the phenomenon observed. The concentration of niobium behind the migrated liquid films for isothermal treatments below the solidus temperature was shown to be greater than the niobium concentration in the matrix. Above the solidus temperature, there was no increase in niobium concentration. The validity of the coherency strain hypothesis as the driving force for CLFM in alloy 718 is discussed.

  10. Structural and dynamical properties of liquid Al-Au alloys

    Science.gov (United States)

    Peng, H. L.; Voigtmann, Th.; Kolland, G.; Kobatake, H.; Brillo, J.

    2015-11-01

    We investigate temperature- and composition-dependent structural and dynamical properties of Al-Au melts. Experiments are performed to obtain accurate density and viscosity data. The system shows a strong negative excess volume, similar to other Al-based binary alloys. We develop a molecular-dynamics (MD) model of the melt based on the embedded-atom method (EAM), gauged against the available experimental liquid-state data. A rescaling of previous EAM potentials for solid-state Au and Al improves the quantitative agreement with experimental data in the melt. In the MD simulation, the admixture of Au to Al can be interpreted as causing a local compression of the less dense Al system, driven by less soft Au-Au interactions. This local compression provides a microscopic mechanism explaining the strong negative excess volume of the melt. We further discuss the concentration dependence of self- and interdiffusion and viscosity in the MD model. Al atoms are more mobile than Au, and their increased mobility is linked to a lower viscosity of the melt.

  11. Activities of liquid Fe-As and Fe-Sb alloys saturated with carbon

    Institute of Scientific and Technical Information of China (English)

    Leandro Voisin; Kimio Itagaki

    2006-01-01

    A solid iron base alloy of the so-called furnace residue is often formed as a by-product in reduction smelting of lead sinter and scraps with high contents of arsenic and antimony. The use of phase separation into a liquid iron-rich alloy and a liquid lead-rich alloy in lead-iron-arsenic and lead-iron-antimony systems saturated with carbon at relatively low temperatures of about 1200℃ was proposed in a new process for treating the furnace residue to recover valuable elements into the lead-rich alloy and fix toxic arsenic into the iron-rich alloy. As a fundamental study for the proposed process, the activity coefficients and interaction parameters of the Fe-As and Fe-Sb systems saturated with carbon at 1200℃ were derived in this study, based on the determined phase relations in the Fe-Pb-As and Fe-Pb-Sb systems saturated with carbon.

  12. Determining the applicability of liquid alloy nitriding in fabrication of Al-AlN particle composites

    Directory of Open Access Journals (Sweden)

    J. Śleziona

    2008-08-01

    Full Text Available One of the possible techniques of the fabrication of dispersion-hardened composites is by in situ reaction between the liquid alloy and gas. The study presents the results of the research on nitriding of liquid aluminium alloy containing Mg and Ti as alloying elements under the conditions of high pressure comprised in the range of 150-1000hPa at the temperature of up to 1100oC. It has been stated that under the applied conditions of the synthesis it is possible to obtain the AlN nitride, but it is formed on the liquid alloy surface and as a deposit on the surface of the crucible. Some results of the analysis of the phase constitution obtained in the fabricated products were presented along with the structure of these products.

  13. Effects of Solid-Liquid Mixing on Microstructure of Semi-Solid A356 Aluminum Alloy

    Science.gov (United States)

    Guo, H. M.; Wang, L. J.; Wang, Q.; Yang, X. J.

    2014-08-01

    The desired starting material for semi-solid processing is the semi-solid slurry in which the solid phase is present as fine and globular particles. A modified solid-liquid mixing (SLM) is reported wherein semi-solid slurry can be produced by mixing a solid alloy block into a liquid alloy, and mechanical vibration is utilized to enhance the mixing. Effects such as liquid alloy temperature, mass ratio, and mixing intensity on the microstructure and the cooling curves during SLM were evaluated. 2D and 3D microstructure analysis of treated A356 aluminum alloy shows that microstructure can be refined significantly with a considerable morphology change in primary Al phase. It is critical that the temperature of mixture after mixing is lower than its liquidus temperature to obtain a valid SLM process. Specially, mixing intensity is identified as a primary factor for a favorable microstructure of semi-solid slurry.

  14. Isothermal corrosion (γ'+γ) Ni3Al alloy in liquid zinc

    Institute of Scientific and Technical Information of China (English)

    WANG Wen-jun; LIN Jun-pin; WANG Yan-li; CHEN Guo-liang

    2006-01-01

    The isothermal corrosion testing and microscopic examination of Ni3Al alloy in liquid zinc containing small amounts of aluminum (mass fraction less than 0.2%) at 450 ℃ were carried out. The results show that the controlling mechanism of the dissolution reaction is diffusion through a boundary layer into liquid zinc. For two-phase alloy, Ni3Al alloy (γ'+γ), the interface between dissolving solid and liquid remains remarkably planar and the difference in dissolution of the two adjacent phases (γ'+γ) can not be experimentally observed. The boundaries between γ' phase and γ phase play no perceptible role in the dissolution of Ni3Al alloy in liquid zinc. The X-ray diffraction spectra of the diffusion layer confirm the presence of Ni5Zn21. The corrosion rate of the Ni3Al alloy in molten zinc was calculated to be approximately 2.6×10-3 g/(cm2-h), therefore the liquid zinc corrosion resistance of Ni3Al alloy is very weak.

  15. Investigation of ordering phenomenon in Me–Pt (Me=Fe,Ni liquid alloys

    Directory of Open Access Journals (Sweden)

    Yisau Adelaja Odusote

    2008-01-01

    Full Text Available The phase diagrams of Fe–Pt and Ni–Pt liquid alloy systems show the existence of FePt and NiPt intermetallic compounds, respectively, in their solid intermediate states, and the associative tendency between unlike atoms in these liquid alloys has been analysed using the self-association model. The concentration dependences of mixing properties such as the free energy of mixing, GM; the concentration fluctuations, Scc(0, in the long-wavelength limits; the chemical short-range order (CSRO parameter, α1; as well as the chemical diffusion, enthalpy and entropy of the mixing of Fe–Pt and Ni–Pt liquid alloys have been investigated to determine the nature of ordering in the liquid alloys. The results show that heterocoordination occurs in the alloys at all concentrations. The effect of CSRO on Scc(0, chemical diffusion, D, and the order parameter, α1, has been considered. The ordering phenomenon in the liquid alloys is also related to the effect of the atomic size mismatch volume on Scc(0.

  16. Structure of liquid caesium-bismuth alloys studied by neutron diffraction

    NARCIS (Netherlands)

    van der Aart, SA; Verhoeven, VWJ; Verkerk, P; van der Lugt, W

    2000-01-01

    Neutron diffraction experiments were carried out for two liquid alloys with compositions CsBi and Cs3Bi2. The results indicate that probably polyanions with an average number of about two Bi atoms per cluster are formed. This result contrasts with that for liquid Cs-Sb, which contains larger chains

  17. Microstructural evolution and mechanical properties of hypereutectic Al–Si alloy processed by liquid die forging

    Indian Academy of Sciences (India)

    F F Wu; S T Li; G A Zhang; F Jiang

    2014-08-01

    The microstructural evolution and mechanical properties of a hypereutectic Al–Si alloy processed by liquid die forging were investigated. It is found that the grain size of the primary Si was significantly reduced by liquid die forging with increased pressure. The volume fraction of eutectic silicon was decreased with increased pressure. By liquid die forging with pressure up to 180 MPa, the average size of the primary Si was reduced to about 18 m, which results in the remarkable increase in the fracture strength and hardness of the hypereutectic Al–Si alloy.

  18. Study of atomic structure of liquid Hg-In alloys using ab-initio molecular dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Nalini; Ahluwalia, P. K. [Department of Physics, Himachal Pradesh University, Shimla(HP)-171005 (India); Thakur, Anil [Department of Physics, Govt. P. G. College Solan (HP)-173212 (India)

    2015-05-15

    Ab-initio molecular dynamics simulations are performed to study the structural properties of liquid Hg-In alloys. The interatomic interactions are described by ab-initio pseudopotentials given by Troullier and Martins. Five liquid Hg-In mixtures (Hg{sub 10}In{sub 90}, Hg{sub 30}In{sub 70}, Hg{sub 50}In{sub 50}, Hg{sub 70}In{sub 30} and Hg{sub 90}In{sub 10}) at 299K are considered. The radial distribution function g(r) and structure factor S(q) of considered alloys are compared with respective experimental results for liquid Hg (l-Hg) and (l-In). The radial distribution function g(r) shows the presence of short range order in the systems considered. Smooth curves of Bhatia-Thornton partial structure factors factor shows the presence of liquid state in the considered alloys.

  19. Fabrication methods and applications of microstructured gallium based liquid metal alloys

    Science.gov (United States)

    Khondoker, M. A. H.; Sameoto, D.

    2016-09-01

    This review contains a comparative study of reported fabrication techniques of gallium based liquid metal alloys embedded in elastomers such as polydimethylsiloxane or other rubbers as well as the primary challenges associated with their use. The eutectic gallium-indium binary alloy (EGaIn) and gallium-indium-tin ternary alloy (galinstan) are the most common non-toxic liquid metals in use today. Due to their deformability, non-toxicity and superior electrical conductivity, these alloys have become very popular among researchers for flexible and reconfigurable electronics applications. All the available manufacturing techniques have been grouped into four major classes. Among them, casting by needle injection is the most widely used technique as it is capable of producing features as small as 150 nm width by high-pressure infiltration. One particular fabrication challenge with gallium based liquid metals is that an oxide skin is rapidly formed on the entire exposed surface. This oxide skin increases wettability on many surfaces, which is excellent for keeping patterned metal in position, but is a drawback in applications like reconfigurable circuits, where the position of liquid metal needs to be altered and controlled accurately. The major challenges involved in many applications of liquid metal alloys have also been discussed thoroughly in this article.

  20. The Knight Shift in Liquid Binary Alloys : An Application of Quantum Chemistry in Liquid- and Solid-state Physics

    NARCIS (Netherlands)

    De Hosson, J. Th. M.; Van Der Lugt, W.

    1979-01-01

    We outline a model for calculating the Knight shifts of Na-23 and Li-7 nuclei in liquid sodium-lithium alloys. The model used for the calculations is based on the "multiple-scattering" model (self-consistent scattered wave). Bearing in mind that there exists an uncertainty of about 5-10% in the valu

  1. Surface properties and wetting behavior of liquid Ag-Sb-Sn alloys

    Directory of Open Access Journals (Sweden)

    Sklyarchuk V.

    2012-01-01

    Full Text Available Surface tension and density measurements of liquid Ag-Sb-Sn alloys were carried out over a wide temperature range by using the sessile drop method. The surface tension experimental data were analyzed by the Butler thermodynamic model in the regular solution approximation. The wetting characteristics of these alloys on Cu and Ni substrates have been also determined. The new experimental results were compared with the calculated values as well as with data available in the literature.

  2. Measurement of Activity of Indium in Liquid Bi-In-Sn Alloys by EMF Method

    Science.gov (United States)

    Kumar, M. R.; Mohan, S.; Behera, C. K.

    2016-08-01

    The electrochemical technique based on a molten salt electrolyte galvanic cell has been used to measure the activity of indium in liquid Bi-In-Sn alloys in the temperature range of 723 K to 855 K along three ternary sections. The activity of tin in Bi-Sn binary alloys has also been measured by the same technique in the above temperature range. The activity of indium in Bi-In-Sn alloys shows negative deviation from Raoult's law for most of the compositions and slight positive deviations for a few indium-rich compositions. The ternary excess molar free energies have been calculated by Darken's treatment. Isoactivity curves at 813 K in the ternary Bi-In-Sn alloys were derived by combining the activity data of In-Sn and Bi-In alloys. The values of excess molar free energy obtained in this study are compared with those calculated from the Muggianu model at 813 K.

  3. Magnetic Susceptibility of liquid Gd-NM (NM = Cu, Ga, Ge) alloys

    Science.gov (United States)

    Shimakura, Hironori; Tahara, Shuta; Okada, Tatsuya; Ohno, Satoru

    2017-08-01

    For rare earth alloys, the indirect interaction of RKKY is at work between rare-earth atoms. Therefore, the magnetism of them depends on the number of conduction electrons and the distance between rare-earth metals. In this work, to reveal the relationship between the number of conduction electrons and magnetic property of rare earth metal alloys, magnetic susceptibility measurements for liquid Gd-NM (NM = Cu, Ga, Ge) was performed by Faraday method. As the results, it was observed that the sign of paramagnetic Curie temperature of Cu-Gd alloys are positive at all composition, while Ga-Gd and Ge-Gd alloys show negative paramagnetic Curie temperature at certain composition. Moreover, it was indicated when the alloy at certain composition shows highest melting temperature, it has the lowest paramagnetic Curie temperature.

  4. Correlation between liquid structure and glass forming ability in glassy Ag-based binary alloys

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The atomic structures of liquid Ag-based binary alloys have been investigated in the solidification process by means of X-ray diffraction. The results of liquid structure show that there is a break point in the mean nearest neighbor distance r1 and the coordination number Nmin for glass-forming liquid, while the correlation radius rc and the coordination number Nmin display a monotone variational trend above the break point. It means glass-forming liquids have a steady changing in structure above liquidus and more inhomogeneous state at liquidus. We conclude that there is a strong correlation between liquid structure and glass forming ability in Ag-based binary alloys.

  5. Evaluation of anti-corrosive lubricating behavior of dicationic ionic liquid coatings for biomedical alloys

    Science.gov (United States)

    Siddiqui, Danyal Alam

    Since their inception, orthopedic implants composed of biomedical alloys have been plagued with failures associated with corrosion and wear processes. Despite current surface treatments and techniques being employed to mitigate corrosion and wear, these failure mechanisms continue to occur as prevalent failure modes. Recently, a novel class of compounds known as ionic liquids has been proposed as a multi-functional coating to protect the surfaces of commercially pure titanium surfaces comprising dental implants. In this study, the goal was to evaluate select formulations of these ionic liquids to serve as anti-corrosive lubricants for titanium and cobalt chromium molybdenum alloys widely used in orthopedic implants. Electrochemical and tribological testing of dicationic imidazolium-based ionic liquids revealed these compounds to be superior candidates as corrosion inhibitors and lubricants of biomedical alloy surfaces.

  6. Electrical Resistivity of Na-K Binary Liquid Alloy Using Ab-Initio Pseudopotentials

    Institute of Scientific and Technical Information of China (English)

    Anil Thakur; P. K. Ahluwalia

    2005-01-01

    @@ The study of electrical resistivity of simple binary liquid alloy Na-K is presented as a function of concentration.Hard sphere diameters of sodium (Na) and potassium (K) are obtained through the inter ionic pair potentials evaluated using Troullier and Martins ab-initio pseudopotentials, which have been used to calculate partial structure factors S(q). The Ziman formula for calculating resistivity of binary liquid alloys has been used. Form factors are calculated using ab-initio pseudopotentials. The results suggest that the first principle approach for calculating pseudopotentials with in the frame work of Ziman formalism is quite successful in explaining the electrical resistivity data of compound forming binary liquid alloys.

  7. The use of alloy 117 as a liquid metal current collector

    Science.gov (United States)

    Maribo, David; Sondergaard, Neal

    1987-09-01

    Low melting point, bismuth based alloys are potential replacements for NaK78 as liquid metal slip ring material because of their lower reactivity and potentially greater hydrodynamic stability. This paper describes experiments with one such alloy in a model of a 300 kW superconducting homopolar motor using close clearance braid type collectors. Slip ring tip velocities varied from 5 to 20 m/s and currents ranging from 500 to 2000 A. Viscous power losses tend to follow a simple turbulent mode. In all, the data supports the use of low melting point alloys as an alternative to Na78.

  8. Electronic structure of liquid iron alloys with manganese, chromium, and vanadium

    Science.gov (United States)

    Kudryavtseva, E. D.; Singer, V. V.; Radovskii, I. Z.; Dovgopol, S. P.; Vorontsov, B. S.; Gel'D, P. V.

    1983-01-01

    Electrical resistivity of liquid FeCr, FeV, and FeMn alloys has been measured in the concentration range between 0 and 70% (by weight) of the dopping element, and over the temperature interval from tmelting to 1750°C. Using the Faber-Ziman-Evans method, concentration dependences of the electrical resistivity of liquid FeCr, FeV, and FeMn alloys have been calculated. Concentration dependences of the number of electrons per atom have been estimated.

  9. Chemical short range order and magnetic correction in liquid manganese-gallium zero alloy

    Science.gov (United States)

    Grosdidier, B.; Ben Abdellah, A.; Osman, S. M.; Ataati, J.; Gasser, J. G.

    2015-12-01

    The Mn66Ga34 alloy at this particular composition is known to be zero alloy in which the linear combination of the two neutron scattering lengths weighted by the atomic compositions vanish. Thus for this specific concentration, the effect of the partial structure factors SNN and SNC is cancelled by a weighted term, which value is zero. Then the measured total structure factor S(q) gives directly the concentration-concentration structure factor SCC(q). We present here the first experimental results of neutron diffraction on the Mn66Ga34 "null matrix alloy" at 1050 °C. The main peak of the experimental SCC(q) gives a strong evidence of a hetero-atomic chemical order in this coordinated alloy. This order also appears in real space radial distribution function which is calculated by the Fourier transform of the structure factor. The degree of hetero-coordination is discussed together with other manganese-polyvalent alloys. However manganese also shows abnormal magnetic scattering in the alloy structure factor which must be corrected. This correction gives an experimental information on the mean effective spin of manganese in this liquid alloy. We present the first critical theoretical calculations of the magnetic correction factor in Mn-Ga zero-alloy based on our accurate experimental measurements of SCC(q).

  10. Anomalous temperature dependence of liquid state density for Ni50Ti50 alloy investigated under electrostatic levitation state

    Science.gov (United States)

    Zou, P. F.; Wang, H. P.; Yang, S. J.; Hu, L.; Wei, B.

    2017-08-01

    The density of liquid Ni-Ti alloys were measured by electrostatic levitation technique and the maximum reduced undercooling of ΔT/TL reaches 0.23. Quite different from the linear relationship between density and temperature for liquid Ni45Ti55 and Ni55Ti45 alloys, the density of liquid Ni50Ti50 alloy displays a nonlinear dependence on temperature. Interestingly, the density increasing tendency of liquid Ni50Ti50 alloy rises more rapidly with the decrease of temperature, which results from the more severe shrinking of the distance among atoms at lower temperatures. In addition, the thermal expansion coefficient of liquid Ni50Ti50 alloy increases linearly with the decrease of temperature.

  11. Energy of formation for AgIn liquid binary alloys along the line of phase separation

    CERN Document Server

    Bhuiyan, G M; Ziauddin-Ahmed, A Z

    2003-01-01

    We have investigated the energy of formation for AgIn liquid binary alloys along the solid-liquid phase separation line. A microscopic theory based on the first order perturbation has been applied. The interionic interaction and a reference liquid are the fundamental components of the theory. These are described by a local pseudopotential and the hard sphere liquids, respectively. The results of calculations reveal a characteristic feature that the energy of formation becomes minimum at the equiatomic composition, and thus indicates maximal mix-ability at this concentration. The energy of formation at a particular thermodynamic state that is at T 1173 K predicts the experimental trends fairly well.

  12. Optical and thermodynamic property measurements of liquid metals and alloys

    Science.gov (United States)

    Weber, J. K. Richard; Krishnan, Shankar; Schiffman, Robert A.; Nordine, Paul C.

    Optical properties and spectral emissivities of liquid silicon, titanium, niobium, and zirconium were investigated by HeNe laser polarimetry at λ = 632.8 nm. The metals were of a high purity and, except for zirconium, clean. The more demanding environmental requirements for eliminating oxide or nitride phases from zirconium were not met. Containerless conditions were achieved by electromagnetic levitation and heating. CO2 laser beam heating was also used to extend the temperature range for stable levitation and to heat solid silicon to form the metallic liquid phase. Corrections to previously reported calorimetric measurements of the heat capacity of liquid niobium were derived from the measured temperature dependence of its spectral emissivity. Property measurements were obtained for supercooled liquid silicon and supercooling of liquid zirconium was accomplished. The purification of liquid metals and the extension of this work on liquids to the measurement of thermodynamic properties and phase equilibria are discussed.

  13. On-demand frequency tunability of fluidic antenna implemented with gallium-based liquid metal alloy

    Science.gov (United States)

    Kim, Daeyoung; Doo, Seok Joo; Won, Heong Sup; Lee, Woojin; Jeon, Jinpyo; Chung, Sang Kug; Lee, Gil-Young; Oh, Semyoung; Lee, Jeong-Bong

    2017-04-01

    We investigated frequency tunability of a microfluidic-based antenna using on-demand manipulation of a gallium-based liquid metal alloy. The fluidic antenna was fabricated by polydimethylsiloxane (PDMS) and filled with the gallium-based liquid metal alloy (Galinstan®). It is composed of a digital number "7"-shaped feedline, and a square-shaped and a digital number "6"-shaped patterns, which are all implemented with the liquid metal. The gallium-based liquid metal was adhered to the channel surface due to its viscous oxide layer originating from the gallium oxide forming when it exposed to the air environment. We treated the liquid metal with hydrochloric acid solution to remove the oxide layer on the surface resulting in easy movement of the liquid metal in the channel, as the liquid metal surface has been transformed to be non-wettable. We controlled the physical length of the liquid metal slug filled in feedline with an applied air pressure, resulting in tuning the resonant frequency ranging from 2.2 GHz to 9.3 GHz. The fluidic antenna properties using the liquid metal's electrical conductivity and mobility were characterized by measuring the return loss (S11), and also simulated with CST Microwave Studio.

  14. Calculation of the thermodynamic properties of liquid Ag–In–Sb alloys

    Directory of Open Access Journals (Sweden)

    DRAGANA ZIVKOVIC

    2006-03-01

    Full Text Available The results of calculations of the thermodynamic properties of liquid Ag–In–Sb alloys are presented in this paper. The Redlich–Kister–Muggianu model was used for the calculations. Based on known thermodynamic data for constitutive binary systems and available experimental data for the investigated ternary system, the ternary interaction parameter for the liquid phase in the temperature range 1000–1200 K was determined. Comparison between experimental and calculated results showed their good mutual agreement.

  15. PREDICTION OF THE MIXING ENTHALPIES OF BINARY LIQUID ALLOYS BY MOLECULAR INTERACTION VOLUME MODEL

    Institute of Scientific and Technical Information of China (English)

    H.W.Yang; D.P.Tao; Z.H.Zhou

    2008-01-01

    The mixing enthalpies of 23 binary liquid alloys are calculated by molecular interaction volume model (MIVM), which is a two-parameter model with the partial molar infinite dilute mixing enthalpies. The predicted values are in agreement with the experimental data and then indicate that the model is reliable and convenient.

  16. GaBi alloy liquid metal ion source for microelectronics research.

    Science.gov (United States)

    Bischoff, L; Pilz, W; Ganetsos, Th; Forbes, R G; Akhmadaliev, Ch

    2007-09-01

    A GaBi alloy liquid metal ion source has been studied. From an analysis of the source mass spectra as a function of emission current, a mechanism is suggested for the production of single- and double-charged ions. There is good agreement with the results of Swanson's investigations of a pure Bi source.

  17. Extended superstructure in Tl-rich liquid Cs-Tl alloys

    NARCIS (Netherlands)

    van der Aart, SA; Verkerk, P; Badyal, YS; van der Lugt, W

    1998-01-01

    The structure factors of liquid caesium-thallium alloys with thallium concentrations of 50 to 85 at. % have been measured by means of neutron diffraction. They exhibit a prepeak which shifts to smaller wave vectors with increasing thallium content. This result is explained using a model in which neu

  18. Neutron diffraction investigation of liquid alkali metal-gallium alloys. Giant cluster formation?

    NARCIS (Netherlands)

    Alvarez, M; Lomba, E; Verkerk, P; van der Aart, SA; Bionducci, M; Mirebeau, [No Value; van der Lugt, W

    Neutron diffraction experiments were performed on the liquid alloys NaGa, NaGa3, KGa3 and CsGa3. The structure factors of KGa3 and CsGa3 display prepeaks at small wavenumbers (0.64 and 0.61 (A) over circle -1, respectively). This may indicate the existence of extremely large aggregates of atoms in

  19. CLUSTERS IN LIQUID K-TL AND CS-TL ALLOYS

    NARCIS (Netherlands)

    VERKERK, P; XU, R; HOWELLS, WS; DEWIJS, GA; VANDERLUGT, W

    1994-01-01

    The structure factors of several liquid K-Tl and Cs-Tl alloys have been measured by means of neutron time-of-flight diffraction at the spallation neutron source ISIS. A large first sharp diffraction peak (FSDP) or prepeak is observed in all measurements at relatively short wave vector, indicating

  20. Trace tritium recovery from the residue of liquid Li17Pb83 alloy

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The liquid Li17Pb83 alloy is a prominent breeder material for use in a fusion reactor.In the design of an effective tritium extraction system for the liquid lithium lead bubbler of the test blanket module of such a reactor,finding ways to strictly limit the losses of tritium and to minimize radioactive risks is very important.For this purpose,the isotope exchange process has been investigated as a means of trace tritium recovery from a model of the residue from Li17Pb83 alloy.The results indicate that the isotope exchange process is an effective means of tritium recovery from the residue of Li17Pb83 alloy,and the optimum composition of the exchange carrier gas is He + 0.1% D2.The exchange temperature and number of exchange steps are the main factors influencing the efficiency of tritium recovery from the residue.Trace tritium recovery efficiency increases with increasing exchange temperature and number of times of exchange.Tritium recovery efficiency can approach 80% when the residue is treated six times at 823 K.A gas-liquid two-phase contact model to describe the proceeding of tritium release from the liquid Li17Pb83 alloy has been derived on the basis of this experiment.

  1. Neutron diffraction investigation of liquid alkali metal-gallium alloys. Giant cluster formation?

    NARCIS (Netherlands)

    Alvarez, M; Lomba, E; Verkerk, P; van der Aart, SA; Bionducci, M; Mirebeau, [No Value; van der Lugt, W

    2002-01-01

    Neutron diffraction experiments were performed on the liquid alloys NaGa, NaGa3, KGa3 and CsGa3. The structure factors of KGa3 and CsGa3 display prepeaks at small wavenumbers (0.64 and 0.61 (A) over circle -1, respectively). This may indicate the existence of extremely large aggregates of atoms in t

  2. Chemical short range order and magnetic correction in liquid manganese–gallium zero alloy

    Energy Technology Data Exchange (ETDEWEB)

    Grosdidier, B. [Laboratoire de Chimie Physique – Approche Multi-Echelle des Milieux Complexes, Institut Jean Bariol, Université de Lorraine, Institut de Chimie, Physique et Matériaux, 1 Bd Arago, 57078 Metz Cedex 3 (France); Ben Abdellah, A. [Laboratoire de Chimie Physique – Approche Multi-Echelle des Milieux Complexes, Institut Jean Bariol, Université de Lorraine, Institut de Chimie, Physique et Matériaux, 1 Bd Arago, 57078 Metz Cedex 3 (France); Innovation and Management of Industrial Systems, Abdelmalek Essaadi University, College of Sciences and Techniques of Tangier , P.O. Box 416, Postal code 90000, Tangier (Morocco); Université Internationale de Rabat, Parc Technopolis Rabat-Shore, 11100 Sala El Jadida (Morocco); Osman, S.M., E-mail: osm@squ.edu.om [Physics Department, College of Science, Sultan Qaboos University, P.O. Box 36, Postal Code 123, Al-Khod, Muscat (Oman); Ataati, J. [Innovation and Management of Industrial Systems, Abdelmalek Essaadi University, College of Sciences and Techniques of Tangier, P.O. Box 416, Postal code 90000, Tangier (Morocco); Gasser, J.G. [Laboratoire de Chimie Physique – Approche Multi-Echelle des Milieux Complexes, Institut Jean Bariol, Université de Lorraine, Institut de Chimie, Physique et Matériaux, 1 Bd Arago, 57078 Metz Cedex 3 (France)

    2015-12-15

    The Mn{sub 66}Ga{sub 34} alloy at this particular composition is known to be zero alloy in which the linear combination of the two neutron scattering lengths weighted by the atomic compositions vanish. Thus for this specific concentration, the effect of the partial structure factors S{sub NN} and S{sub NC} is cancelled by a weighted term, which value is zero. Then the measured total structure factor S(q) gives directly the concentration–concentration structure factor S{sub CC}(q). We present here the first experimental results of neutron diffraction on the Mn{sub 66}Ga{sub 34} “null matrix alloy” at 1050 °C. The main peak of the experimental S{sub CC}(q) gives a strong evidence of a hetero-atomic chemical order in this coordinated alloy. This order also appears in real space radial distribution function which is calculated by the Fourier transform of the structure factor. The degree of hetero-coordination is discussed together with other manganese-polyvalent alloys. However manganese also shows abnormal magnetic scattering in the alloy structure factor which must be corrected. This correction gives an experimental information on the mean effective spin of manganese in this liquid alloy. We present the first critical theoretical calculations of the magnetic correction factor in Mn–Ga zero-alloy based on our accurate experimental measurements of S{sub CC}(q).

  3. Diffusion dynamics in liquid and undercooled Al-Ni alloys

    Energy Technology Data Exchange (ETDEWEB)

    Stueber, Sebastian

    2009-10-05

    This work presents data on Ni self-diffusion in binary Al-Ni alloys with high precision. For this, we combined two techniques: containerless electromagnetic levitation to position the samples, and neutron time-of-flight spectroscopy to measure the decay of the self-correlation. This combination offers new measurement ranges, especially at low temperatures, several hundreds of Kelvin below the liquidus temperature. Because without container, the primary cristallization seeds for the metallic melt are avoided. But it is also possible to measure reactive samples, and at very high temperatures at and above 2000K, as problematic reactions with the containing cask won't occur. Furthermore this technique also enables measurements at higher momentum transfer q, as one does not have to limit the q-range of the measurement to avoid Bragg peaks of the solid container material. By this time-of-flight spectroscopy on levitated metallic melts, it is possible to determine the Ni self-diffusion in these alloys directly and on an absolute scale. The dependence of the Ni self-diffusion coefficient on temperature and concentration was studied in pure Ni and binary Al-Ni alloys. In a temperature range of several hundred degrees, we always found Arrhenius-like temperature dependence of the diffusion, irrespective of possible undercooling. In the context of these measurements, we also studied the interdependence between diffusivity in the metallic melt and its quasielastic structure factor. Time-of-flight spectroscopy made it also possible to derive the dynamic partial structure factors of the binary alloy Al{sub 80}Ni{sub 20}. All this to enable a better understanding of the atomic processes in the metallic melt, especially of the undercooled melt, as an alloy is always formed out of the (undercooled) melt of its stoichiometric compounds. For this, material transport and diffusion are immensely important. The final goal would be materials design from the melt, i.e. the prediction

  4. The liquid phase separation of Bi-Ga hypermonotectic alloy under acoustic levitation condition

    Institute of Scientific and Technical Information of China (English)

    HONG ZhenYu; L(U) YongJun; XIE WenJun; WEI BingBo

    2007-01-01

    Containerless treatment of Bi-58.5at%Ga hypermonotectic alloy is successfully performed with acoustic levitation technique. Under acoustic levitation condition, the second phase (Ga) distributes almost homogeneously in solidification sample, opposite to macrosegregation in solidification sample under conventional condition. Stokes motion of the second liquid droplet (Ga) is significantly restrained under acoustic levitation condition. The analyses indicate that the melt vibration in the gravity direction forced by acoustic field can induce steady flow around the second liquid droplet, which influences droplet shape during its moving upward and consequently restrains Stokes motion velocity of the second liquid droplet.

  5. 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.

  6. Tape transfer atomization patterning of liquid alloys for microfluidic stretchable wireless power transfer.

    Science.gov (United States)

    Jeong, Seung Hee; Hjort, Klas; Wu, Zhigang

    2015-02-12

    Stretchable electronics offers unsurpassed mechanical compliance on complex or soft surfaces like the human skin and organs. To fully exploit this great advantage, an autonomous system with a self-powered energy source has been sought for. Here, we present a new technology to pattern liquid alloys on soft substrates, targeting at fabrication of a hybrid-integrated power source in microfluidic stretchable electronics. By atomized spraying of a liquid alloy onto a soft surface with a tape transferred adhesive mask, a universal fabrication process is provided for high quality patterns of liquid conductors in a meter scale. With the developed multilayer fabrication technique, a microfluidic stretchable wireless power transfer device with an integrated LED was demonstrated, which could survive cycling between 0% and 25% strain over 1,000 times.

  7. A generalized model on the evaluation of entropy and entropy of mixing of liquid Na-Sn alloys

    Science.gov (United States)

    Satpathy, Alok; Sengupta, Saumendu

    2017-01-01

    Recently proposed theory of entropy of mixing of the structurally inhomogeneous binary liquid alloys of alkali metals and group-IV elements is applied successfully to the liquid Na-Sn alloy. This alloy indicates chemical short range ordering (CSRO) i.e. exhibits partially salt like characteristics due to strong tendencies to compound formation, in the solid as well as in the liquid state. So, the generalized model for entropy of charged-hard-spheres mixture of arbitrary charge and size is employed to evaluate entropies of mixing, treating the sample as partially charge transfer system. The computed entropies of mixing are in excellent agreement with the experimental data.

  8. Electrolytic preparation of Al-Ca master alloy on liquid Al cathode

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    As a newly developing superplastic aluminum alloy, Al-Ca alloy has been widely used in industry, however thetechnology for preparing Al-Ca master alloy and its influencing factors need to be further studied. Therefore the Al-Camaster alloy was prepared by using liquid aluminum cathode and a mixture of 80%CaC12-18% KC1-2%CaF2 as the moltensalt electrolysis in a laboratory electrolyte cell; the effects of electrolysis temperature, cathodic current density and electrolytic duration on current efficiency and Ca content of Al-Ca alloy as well were studied. Through laboratory experiments, the parameters for smooth electrolytic reaction were proposed. The proper electrolysis technology is as follows:with the 80%CaCl2-18%KCl-2%CaF2 electrolyte, the electrolytic temperature is 973 K and the cathodic current densityis 0.8 A/cm2, the electrolysis can go on smoothly and a calcium content of 17.5%(mass fraction) can be obtained. Withthe increase of electrolysis duration, the calcium content in the alloy increasas whereas the current efficiency decreases

  9. Solid-liquid phase equilibria of Fe-Cr-Al alloys and spinels

    Science.gov (United States)

    McMurray, J. W.; Hu, R.; Ushakov, S. V.; Shin, D.; Pint, B. A.; Terrani, K. A.; Navrotsky, A.

    2017-08-01

    Ferritic FeCrAl alloys are candidate accident tolerant cladding materials. There is a paucity of data concerning the melting behavior for FeCrAl and its oxides. Analysis tools have therefore had to utilize assumptions for simulations using FeCrAl cladding. The focus of this study is to examine in some detail the solid-liquid phase equilibria of FeCrAl alloys and spinels with the aim of improving the accuracy of severe accident scenario computational studies.

  10. Surface and transport properties of Cu-Sn-Ti liquid alloys

    Institute of Scientific and Technical Information of China (English)

    R. Novakovic; E. Ricci; S. Amore; T. Lanata

    2006-01-01

    The lack of experimental data and / or limited experimental information concerning both surface and transport properties of liquid alloys often require the prediction of these quantities. An attempt has been made to link the thermophysical properties of a ternary Cu-Sn-Ti system and its binary Cu-Sn, Cu-Ti and Sn-Ti subsystems with the bulk through the study of the concentration dependence of various thermodynamic, structural, surface and dynamic properties in the frame of the statistical mechanical theory in conjunction with the quasi-lattce theory (QLT). This formalism provides valuable qualitative insight into mixing processes that occur in molten alloys.

  11. Surface tension of liquid Au-Bi-Sn alloys

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    The surface tension of a promising lead-free solder Au-Bi-Sn alloys was investigated both by the sessile-drop method and calculation. Experimental measurements were carried out for two cross-sections with the constant gold to bismuth ration of 1:1 and 1:2. For all the investigated compositions, decrease of the surface tension is observed with increasing temperature. Meanwhile, the surface tension values were also calculated based on Butler's equation, with using the newest research on thermodynamics data of...

  12. Phase field simulation of monotectic transformation for liquid Ni-Cu-Pb alloys

    Institute of Scientific and Technical Information of China (English)

    LUO BingChi; WANG HaiPeng; WEI BingBo

    2009-01-01

    Based on the subregular solution model, the liquid phase separation of ternary (NixCu100-x)50Pb50monotectic alloys is simulated by the phase field method. It is found that if the surface segregation potential is not incorporated, the dynamic morphologies of alloy melt show a transition from disperse microstructure into bicontinuous microstructure with the increase of fluidity parameter. When the sur-face segregation potential is coupled, Pb-rich phase migrates preferentially to the surface of the liquid alloy, and the Ni-rich phase depends on the Pb-rich phase to nucleate. With the extension of the phase separation time, the surface layer is formed through coagulation and growth, and its thickness gradu-ally increases. The Ni-rich phase migrates to the central part, and finally a two-layer core-shell micro-structure is produced. The concentration in the surface layer fluctuates more conspicuously than that inside the bulk phase, which subsequently transfers from the surface to the interior by a wave. The fluid field near the liquid-liquid interface is strong at the beginning of phase separation, and reduces later on. The surface segregation is essential to the formation of the surface layer, concentration profile variation, fluid field distribution and phase separation morphology.

  13. Thermodynamic properties of liquid Au-Cu-Sn alloys determined from electromotive force measurements

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Zhongnan, E-mail: guozhongn@163.com [Institute of Inorganic chemistry/Material chemistry, University of Vienna, A-1090 Vienna (Austria); Department of Chemistry, School of Chemical and Biological engineering, University of Science and Technology Beijing, 100083 Beijing (China); Hindler, Michael [Institute of Inorganic chemistry/Material chemistry, University of Vienna, A-1090 Vienna (Austria); Yuan, Wenxia [Department of Chemistry, School of Chemical and Biological engineering, University of Science and Technology Beijing, 100083 Beijing (China); Mikula, Adolf [Institute of Inorganic chemistry/Material chemistry, University of Vienna, A-1090 Vienna (Austria)

    2011-10-20

    Highlights: {yields} A full thermodynamic description of the liquid ternary Au-Cu-Sn system is reported. {yields} The electromotive force method with a liquid electrolyte was used to determine the activity of tin in the alloys. {yields} The partial free energies of tin in this system were calculated from the obtained EMF values. {yields} The Gibbs-Duhem integration was used to calculate the integral Gibbs free energy and integral enthalpy of the entire system. - Abstract: The thermodynamic properties of the ternary Au-Cu-Sn system were determined with the electromotive force (EMF) method using a liquid electrolyte. Three different cross-sections with constant Au:Cu ratios of 3:1, 1:1, and 1:3 were applied to measure the thermodynamic properties of the ternary system in the temperature range between the liquidus temperature of the alloys and 1023 K. The partial free energies of Sn in liquid Au-Cu-Sn alloys were obtained from EMF data. The integral Gibbs free energy and the integral enthalpy at 900 K were calculated by Gibbs-Duhem integration. The ternary interaction parameters were evaluated using the Redlich-Kister-Muggianu polynomial.

  14. Thermodynamic properties of liquid Al–Li–Zn alloys determined from electromotive force measurement

    Energy Technology Data Exchange (ETDEWEB)

    Trybula, Marcela, E-mail: m.trybula@imim.pl; Fima, Przemysław; Gąsior, Władysław

    2014-07-01

    Highlights: • Electromotive force (emf) was measured in liquid Al–Li–Zn alloys. • Partial thermodynamic properties (ΔG, ΔH, ΔS) were determined from emf data. • A set of Redlich–Kister (RK) parameters for liquid was optimized using these data. • Partial and mixing ΔG and ΔH were modelled using new and literature RK parameters. • Calculated mixing enthalpy is in good agreement with literature calorimetric data. - Abstract: Electromotive force measurements (emf) were carried out over broad temperature range for liquid ternary Al–Li–Zn alloys. Partial excess thermodynamic functions of lithium: Gibbs energy, enthalpy and entropy in liquid Al–Li–Zn alloys were determined. These data were compared to modelled values obtained using Redlich–Kister–Muggianu (RMK) equation and the set of literature binary and ternary interaction parameters. Mixing Gibbs energy and enthalpy was also computed with the new set of ternary parameters optimized in this work and confronted to available experimentally determined data.

  15. Modeling the diffusion of solid copper into liquid solder alloys

    Energy Technology Data Exchange (ETDEWEB)

    Rizvi, M.J. [School of Computing and Mathematical Sciences, University of Greenwich, 30 Park Row, London, SE10 9LS (United Kingdom)], E-mail: rm77@gre.ac.uk; Lu, H.; Bailey, C. [School of Computing and Mathematical Sciences, University of Greenwich, 30 Park Row, London, SE10 9LS (United Kingdom)

    2009-01-01

    During the soldering process, the copper atoms diffuse into liquid solders. The diffusion process determines integrity and the reworking possibility of a solder joint. In order to capture the diffusion scenarios of solid copper into liquid Sn-Pb and Sn-Cu solders, a computer modeling has been performed for 10 s. An analytical model has also been proposed for calculating the diffusion coefficient of copper into liquid solders. It is found that the diffusion coefficient for Sn-Pb solder is 2.74 x 10{sup -10} m{sup 2}/s and for Sn-Cu solder is 6.44 x 10{sup -9} m{sup 2}/s. The modeling results reveal that the diffusion coefficient is one of the major factors that govern the rate at which solid Cu dissolve in the molten solder. The predicted dissolved amounts of copper into solders have been validated with the help of scanning electron microscopic analysis.

  16. Surface tension of liquid metals and alloys--recent developments.

    Science.gov (United States)

    Egry, I; Ricci, E; Novakovic, R; Ozawa, S

    2010-09-15

    Surface tension measurements are a central task in the study of surfaces and interfaces. For liquid metals, they are complicated by the high temperatures and the consequently high reactivity characterising these melts. In particular, oxidation of the liquid surface in combination with evaporation phenomena requires a stringent control of the experimental conditions, and an appropriate theoretical treatment. Recently, much progress has been made on both sides. In addition to improving the conventional sessile drop technique, new containerless methods have been developed for surface tension measurements. This paper reviews the experimental progress made in the last few years, and the theoretical framework required for modelling and understanding the relevant physico-chemical surface phenomena.

  17. Thermodynamic properties of the liquid Bi-Cu-Sn lead-free solder alloys

    Directory of Open Access Journals (Sweden)

    Kopyto M.

    2009-01-01

    Full Text Available The electromotive force measurement method was employed to determine the thermodynamic properties of liquid Bi-Cu-Sn alloys using solid electrolyte galvanic cells as shown below: Kanthal+Re, Bi-Cu-Sn, SnO2 | Yttria Stabilized Zirconia | air, Pt, Po2=0.2:1 atm Measurements were carried out for three cross-sections with constant Bi/Cu ratio equal to: 1/3, 1 and 3 and for various tin content varying every 10%, resulting in a total of 26 different alloy compositions. The temperature of the measurements varied within the range from 973 to 1325 K. A linear dependence of the e.m.f. on temperature was observed for all alloy compositions and the appropriate line equations were derived. Tin activities were calculated as function of composition and temperature. Results were presented in tables and figures.

  18. Analysis of stability of a planar solid-liquid interface in a dilute binary alloy

    Science.gov (United States)

    Laxmanan, V.

    1990-01-01

    This paper reconsiders the question of stability of a planar solid-liquid interface in an undercooled alloy melt without making the restrictive assumption of no heat flow in the solid (i.e., Gs = 0). The results of this analysis indicate that, provided the thermal gradient on the solid side of the interface, Gs, is positive, stability can be achieved in an undercooled alloy melt for growth rates R greater than Ra (where Ra is the absolute stability limit of Mullins and Sekerka, 1964). Thus, the absolute stability criterion for steady-state planar growth in an undercooled alloy melt is the same as derived earlier by Mullins and Sekerka for directional solidification. Relaxing the restrictive assumption of Gs = 0 also reveals that there is a regime of stability for low growth rates and low supercoolings.

  19. Optimization method for the study of the properties of Al-Sn binary liquid alloys

    Energy Technology Data Exchange (ETDEWEB)

    Shrestha, G.K. [University Department of Physics, T.M. Bhagalpur University, Bhagalpur (India); Pulchowk Campus, IOE, Tribhuvan University, Lalitpur (Nepal); Singh, B.K. [University Department of Physics, T.M. Bhagalpur University, Bhagalpur (India); Jha, I.S. [M.M.A.M. Campus, Tribhuvan University, Biratnagar (Nepal); Singh, B.P. [University Department of Physics, T.M. Bhagalpur University, Bhagalpur (India); Adhikari, D., E-mail: adksbdev@yahoo.com [M.M.A.M. Campus, Tribhuvan University, Biratnagar (Nepal)

    2017-06-01

    The best fit value of order energy parameter (W) has been estimated over the entire range of concentration in Al-Sn binary liquid alloy at a specified temperature to determine the thermodynamic properties and concentration fluctuations, obtained by a theoretical formalism in which the combined effect of size ratio, entropic and enthalpic effect is considered. The values of W at different temperatures have been determined by finding the temperature derivative of W which are then used for the optimization procedure in order to determine the corresponding values of excess free energy of mixing, partial excess free energy of mixing and activity of the components involved in the alloy. These parameters have been used to calculate the concentration fluctuations in long wavelength limit {S_c_c(0)} at different temperatures over the entire range of concentration which predict the stability of the alloy at different temperatures.

  20. Short-Range Order in Liquid Al-Cu-Ni-Ce Alloy

    Institute of Scientific and Technical Information of China (English)

    孙民华; 边秀房

    2002-01-01

    The liquid and amorphous structures of Al85Ni10Ce5 and Al85Cu5Ni5Ce5 alloy were studied by X-ray diffraction. The position of the first peak shifts to bigger Q-values as the concentration of Cu increases. Gaussian decomposition of first peak in radical distribution function (RDF) was applied to Al-Ni(Cu)-Ce system. The bond lengths of Al-Al, Al-TM(Transition metal) and TM-TM increase with the substitution of Ni by Cu. Viscosity measurement shows that viscosity of Al-Ni-Ce alloy increases faster than that of Al-Ni-Cu-Ce alloy. The addition of Cu can decrease the interaction between atoms, so it is unfavorable to Al-based glass formability.

  1. Thermodynamic properties and atomic structure of Ca-based liquid alloys

    Science.gov (United States)

    Poizeau, Sophie

    To identify the most promising positive electrodes for Ca-based liquid metal batteries, the thermodynamic properties of diverse Ca-based liquid alloys were investigated. The thermodynamic properties of Ca-Sb alloys were determined by emf measurements. It was found that Sb as positive electrode would provide the highest voltage for Ca-based liquid metal batteries (1 V). The price of such a battery would be competitive for the grid-scale energy storage market. The impact of Pb, a natural impurity of Sb, was predicted successfully and confirmed via electrochemical measurements. It was shown that the impact on the open circuit voltage would be minor. Indeed, the interaction between Ca and Sb was demonstrated to be much stronger than between Ca and Pb using thermodynamic modeling, which explains why the partial thermodynamic properties of Ca would not vary much with the addition of Pb to Sb. However, the usage of the positive electrode would be reduced, which would limit the interest of a Pb-Sb positive electrode. Throughout this work, the molecular interaction volume model (MIVM) was used for the first time for alloys with thermodynamic properties showing strong negative deviation from ideality. This model showed that systems such as Ca-Sb have strong short-range order: Ca is most stable when its first nearest neighbors are Sb. This is consistent with what the more traditional thermodynamic model, the regular association model, would predict. The advantages of the MIVM are the absence of assumption regarding the composition of an associate, and the reduced number of fitting parameters (2 instead of 5). Based on the parameters derived from the thermodynamic modeling using the MIVM, a new potential of mixing for liquid alloys was defined to compare the strength of interaction in different Ca-based alloys. Comparing this trend with the strength of interaction in the solid state of these systems (assessed by the energy of formation of the intermetallics), the systems with

  2. THE STRUCTURE OF LIQUID LI-SI ALLOYS

    NARCIS (Netherlands)

    DEJONG, PHK; VERKERK, P; VANDERLUGT, W; DEGRAAF, LA

    1993-01-01

    The reverse Monte Carlo method is used to analyse neutron diffraction data on liquid Li65Si35. A well defined Si-Si partial pair correlation function is obtained with strong indications for covalent Si-Si bonds. It is also clear that most of the Si4 stars and Si5 rings occurring in solid Li12Si7 hav

  3. Transport properties and Stokes-Einstein relation in Al-rich liquid alloys

    Science.gov (United States)

    Jakse, N.; Pasturel, A.

    2016-06-01

    We use ab initio molecular dynamics simulations to study the transport properties and the validity of the Stokes-Einstein relation in Al-rich liquid alloys with Ni, Cu, and Zn as alloying elements. First, we show that the composition and temperature dependence of their transport properties present different behaviors, which can be related to their local structural ordering. Then, we evidence that the competition between the local icosahedral ordering and the local chemical ordering may cause the breakdown of the Stokes-Einstein relation even in the liquid phase. We demonstrate that this breakdown can be captured by entropy-scaling relationships developed by Rosenfeld and using the two-body excess entropy. Our findings provide a unique framework to study the relation between structure, thermodynamics, and dynamics in metallic melts and pave the way towards the explanation of various complex transport properties in metallic melts.

  4. Theoretical studies of mutual diffusivities and surface properties in Cd–Ga liquid alloys

    Indian Academy of Sciences (India)

    B C Anusionwu; C A Madu; C E Orji

    2009-06-01

    The mutual diffusion coefficients, activation energy for diffusion, surface concentration and surface tension of the liquid Cd–Ga alloys have been calculated throughout the concentration range using energetics obtained from the theoretical model fits of the experimental thermodynamic data. Our calculations show that Cd–Ga liquid alloys showed immiscibility at a temperature of 723 K between 0.4 and 0.5 atomic fraction of Cd. Within this concentration region and temperature, the mutual diffusion coefficients approached zero values and the activation energy for diffusion reached high peak values of 220 J/mol. It was also observed that within the region of immscibility, the diffusion coefficients do not obey Arrhenius relation over a wide range of temperature.

  5. Surface tension and specific heat of liquid Ni70.2Si29.8 alloy

    Institute of Scientific and Technical Information of China (English)

    WANG Haipeng; WEI Bingbo

    2005-01-01

    The surface tension and specific heat of stable and metastable liquid Ni70.2Si29.8 eutectic alloy were measured by electromagnetic levitation oscillating drop method and drop calorimetry. The surface tension depends on temperature linearly within the experimental undercooling regime of 0-182 K (0.12 TE). Its value is 1.693 N·m-1 at the eutectic temperature of 1488 K, and the temperature coefficient is -4.23×10-4 N·m-1·K-1. For the specific heat measurement, the maximum undercooling is up to 253 K (0.17 TE). The specific heat is determined as a polynomial function of temperature in the experimental temperature regime. On the basis of the measured data of surface tension and specific heat, the temperature-dependent density, excess volume and sound speed of liquid Ni70.2Si29.8 alloy are predicted theoretically.

  6. Thermodynamic properties of liquid Au–Cu–Sn alloys determined from electromotive force measurements

    Science.gov (United States)

    Guo, Zhongnan; Hindler, Michael; Yuan, Wenxia; Mikula, Adolf

    2011-01-01

    The thermodynamic properties of the ternary Au–Cu–Sn system were determined with the electromotive force (EMF) method using a liquid electrolyte. Three different cross-sections with constant Au:Cu ratios of 3:1, 1:1, and 1:3 were applied to measure the thermodynamic properties of the ternary system in the temperature range between the liquidus temperature of the alloys and 1023 K. The partial free energies of Sn in liquid Au–Cu–Sn alloys were obtained from EMF data. The integral Gibbs free energy and the integral enthalpy at 900 K were calculated by Gibbs–Duhem integration. The ternary interaction parameters were evaluated using the Redlich–Kister–Muggianu polynomial. PMID:22039311

  7. Thermodynamic properties of liquid Au-Cu-Sn alloys determined from electromotive force measurements.

    Science.gov (United States)

    Guo, Zhongnan; Hindler, Michael; Yuan, Wenxia; Mikula, Adolf

    2011-10-20

    The thermodynamic properties of the ternary Au-Cu-Sn system were determined with the electromotive force (EMF) method using a liquid electrolyte. Three different cross-sections with constant Au:Cu ratios of 3:1, 1:1, and 1:3 were applied to measure the thermodynamic properties of the ternary system in the temperature range between the liquidus temperature of the alloys and 1023 K. The partial free energies of Sn in liquid Au-Cu-Sn alloys were obtained from EMF data. The integral Gibbs free energy and the integral enthalpy at 900 K were calculated by Gibbs-Duhem integration. The ternary interaction parameters were evaluated using the Redlich-Kister-Muggianu polynomial.

  8. Bulk and Surface Properties of Liquid Al-Li and Li-Zn Alloys

    Science.gov (United States)

    Trybula, Marcela; Gancarz, Tomasz; Gasior, Wladyslaw; Pasturel, Alain

    2014-11-01

    Physicochemical properties like density, surface tension, and viscosity of liquid binary Al-Li and Li-Zn alloys have been measured using draining crucible method. The experimentally measured surface-tension values have been compared to theoretical results based either on the Butler model or the compound formation model assuming the existence of the most favored A 1 B 2 and A 2 B 3 clusters. Several models for viscosity calculation have been also applied and discussed in confrontation with measured data. Finally, the clustering effects in the liquid Al-Li and Li-Zn alloys have been examined using two microscopic functions, i.e., the concentration fluctuation function in the long-wavelength limit and the Warren-Cowley short-range order parameter.

  9. Explosive device of conduit using Ti Ni alloy

    Directory of Open Access Journals (Sweden)

    A. Yu. Kolobov

    2014-01-01

    Full Text Available Presently, materials have been developed which are capable at changing temperate to return significant inelastic deformations, exhibit rubber-like elasticity, convert heat into mechanical work, etc. The aggregate of these effects is usually called the shape memory effect.At present a great number of compounds and alloys with a shape memory effect has been known.These are alloys based on titanium nickelide (TiNi, copper-based alloys (Cu-Al, Cu-Sn, Cu-Al-Ni, Cu-Zn-Si, etc., gold and silver (Ag-Cd, Au-Ag-Cd, Au-Cd-Cu, Au-Zn-Cu, etc., manganese (Mn-Cr, Fe-Cu, Mn-Cu-Ni, Mn-Cu-Zr, Mn-Ni, etc., iron (Fe-Mn, Fe-Ni, Fe-Al, etc., and other compounds.The alloys based on titanium nickelide (nitinol are the most widely used.Alloys with shape memory effect find various applications in engineering and medicine, namely connecting devices, actuators, transformable design, multipurpose medical implants, etc.There is a task of breaking fuel conduit during separating the spacecraft from the rocket in space technology.The paper examines the procedure for design calculation of the separating device of conduit with the use of Ti-Ni alloy. This device can be used instead of the pyro-knives.The device contains two semi-rings from Ti-Ni alloy. In the place of break on the conduit an annular radius groove is made.At a temperature of martensite passage the semi-rings undergo deformation and in the strained state are set in the device. With heating to the temperature of the austenitic passage of bushing macro-deformation the energy stored by the nitinol bushing is great enough to break the conduit on the neck.The procedures of design calculation and response time of device are given.

  10. PREDICTION ON THE THERMODYNAMIC PROPERTIES OF TERNARY LIQUID ALLOYS BY MODIFIED COORDINATION EQUATION

    Institute of Scientific and Technical Information of China (English)

    D.P.Tao

    2001-01-01

    The coordination numbers in the Molecular Interaction Volume Model can be calcu-lated from the common physical quantities of pure matters.A significant advantage ofthe model lies in its ability to predict the thermodynamic properties of ternary liqmdalloys using only the binary infinite dilute activity coefficients,and the predicted values are in good agreement with the experimental data of ternary liquid alloys,whichshows that the model is reliable,convenient and economic.

  11. Pressure-induced structural change in liquid GaIn eutectic alloy

    DEFF Research Database (Denmark)

    Yu, Q.; Ahmad, A. S.; Ståhl, Kenny

    2017-01-01

    Synchrotron x-ray diffraction reveals a pressure induced crystallization at about 3.4 GPa and a polymorphic transition near 10.3 GPa when compressed a liquid GaIn eutectic alloy up to ~13 GPa at room temperature in a diamond anvil cell. Upon decompression, the high pressure crystalline phase rema...... in local atomic packing of the nearest neighbors as well as electronic structures at the transition pressure....

  12. Hard rhenium–boron–cobalt amorphous alloys with a wide supercooled liquid region

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jianfeng, E-mail: jfwang316@zzu.edu.cn [School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001 (China); Zhu, Shijie; Wang, Liguo; Guan, Shaokang [School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001 (China); Li, Ran; Zhang, Tao [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China)

    2015-10-01

    Novel Re–B–Co amorphous alloys with compositions of Re{sub 65−x}B{sub 35}Co{sub x} (at%, x=25, 30, 35, 40, 45, and 50) were fabricated by single-roller melt spinning. These alloys were found to exhibit a clear glass transition phenomenon. The width of supercooled liquid region (ΔT{sub x}) is in the range of 52–71 K. Such a large ΔT{sub x} allows us to produce amorphous alloy bulks by thermoplastic forming. The Vickers hardness is up to 19.10 GPa for the Re{sub 40}B{sub 35}Co{sub 25} alloy, which is close to that reported for some hard covalent crystals. Thus, the present alloys with a combination of large ΔT{sub x} and high hardness are expected to be used as a new type of structural materials. Furthermore, the relationships of hardness with glass transition temperature and Young's modulus were also discussed.

  13. 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.

  14. Electrophysical and structure-sensitive properties of liquid Ga-In alloys

    Energy Technology Data Exchange (ETDEWEB)

    Plevachuk, Yuriy; Sklyarchuk, Vasyl [Ivan Franko National Univ., Lviv (Ukraine). Dept. of Metal Physics; Shevchenko, Natalia; Eckert, Sven [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany)

    2015-01-15

    The broad interest in the thermophysical properties of gallium-based melts is stimulated by their extensive use in various applications, such as sliding contacts, heat-sensitive elements of liquid-metal thermometers and thermocouples, carrier liquid for conducting magnetic fluids and the working medium for physical modeling in solidification and magnetohydrodynamic studies. The electrical conductivity, thermal conductivity, viscosity, density and thermoelectric power were determined for different alloy compositions in a wide temperature range below and above the liquidus. Respective scaling relations are proposed. A comparison with data available in literature is given.

  15. Calorimetric Measurements of Liquid Al-Zn Alloys

    Science.gov (United States)

    Dębski, Adam; Gąsior, Władysław; Szmit, Katarzyna

    2016-10-01

    The integral molar enthalpies of mixing were determined by the drop calorimetric method for binary AL-Zn liquid solutions and compared with the Miedema model as well as the earlier experimental data. The measurements were conducted at two temperatures: 957 K and 1001 K (684 °C and 728 °C), in the entire concentration range. Based on the experimental calorimetric data of this study as well as those available in the literature and the results of the activity studies, the interaction parameters of the Redlich-Kister equation for the liquid Al-Zn phase were worked out with the use of the least square method. The partial and integral Gibbs energies, entropies and enthalpies were calculated and presented in tables and figures. Additionally, the concentration-concentration partial structure factors for the ideal and real Al-Zn solutions were calculated and graphically presented.

  16. Modeling the Hydrogen Solubility in Liquid Aluminum Alloys

    Science.gov (United States)

    Harvey, Jean-Philippe; Chartrand, Patrice

    2010-08-01

    The modeling of hydrogen solubility in multicomponent Al-(Li, Mg, Cu, and Si) liquid phase has been performed with a thermodynamic approach using the modified quasichemical model with the pair approximation (MQMPA). All hydrogen solubility data available in literature was assessed critically to obtain the binary parameters of the MQMPA model for the Al-H, Li-H, Mg-H, Cu-H, Zn-H, and Si-H melts. For the Li-H system, a new thermodynamic description of the stable solid lithium hydride was determined based on the c p found in literature. The thermodynamic model for the Al-Li system also was reassessed in this work to take into account the short-range ordering observed for this system. Built-in interpolation techniques allow the model to estimate the thermodynamic properties of the multicomponent liquid solution from the liquid model parameters of the lower order subsystems. A comparison of the calculated hydrogen solubility performed at various equilibrium conditions of temperature, pressure, and composition with the available experimental data found in the literature is presented in this work, as well as a comparison with some results from previous modeling.

  17. Enthalpy of mixing of liquid Ag–Bi–Cu alloys at 1073 K

    Energy Technology Data Exchange (ETDEWEB)

    Fima, Przemysław, E-mail: p.fima@imim.pl [Institute of Metallurgy and Materials Science, Polish Academy of Sciences, ul. Reymonta 25, 30-059 Krakow (Poland); Flandorfer, Hans [Department of Inorganic Chemistry/Materials Chemistry, University of Vienna, Waehringer Street 42, A-1090 Vienna (Austria)

    2014-01-10

    Highlights: • Partial and integral mixing enthalpies of liquid Ag–Bi–Cu alloys were determined. • Integral mixing enthalpies are small and endothermic, similar to limiting binaries. • The ternary data were fitted on the basis of Redlich–Kister–Muggianu model. - Abstract: The Ag–Bi–Cu system is among those ternary systems which have not been fully studied yet, in particular the thermodynamic description of the liquid phase is missing. Partial and integral enthalpies of mixing of liquid ternary Ag–Bi–Cu alloys were determined over a broad composition range along six sections: x(Ag)/x(Bi) = 0.25, 1, 4; x(Ag)/x(Cu) = 1.5; x(Bi)/x(Cu) = 1.86, 4. Measurements were carried out at 1073 K using two Calvet type microcalorimeters and drop calorimetric technique. It was found that integral enthalpies of mixing are small and endothermic, similarly to limiting binary alloys. The ternary data were fitted on the basis of an extended Redlich–Kister–Muggianu model for substitutional solutions. There are no significant additional ternary interactions.

  18. Temperature dependence of the bulk and surface properties of liquid Zn-Cd alloys

    Energy Technology Data Exchange (ETDEWEB)

    Awe, O.E. [University of Ibadan, Department of Physics, Ibadan (Nigeria); Azeez, A.A. [African University of Science and Technology, Abuja (Nigeria)

    2017-05-15

    The effects of temperature on the bulk and surface properties of liquid Zn-Cd alloys have been theoretically investigated, using a combination of self association model, Darken's thermodynamic equation for diffusion, empirical model for viscosity and a statistical mechanics model. The results from this study show that change in temperature resulted in cross-over effects in bulk and surface properties. We also found that with an increase in temperature, a pronounced asymmetry of viscosity isotherm is significantly reduced, and viscosity isotherm exhibited anomalous behaviour. Our results reveal that the homocoordination tendency in Zn-Cd liquid alloys is not strong and reduces with increasing temperature. The study further suggests a pronounced segregation of Cd-atoms at the surface of Zn-Cd liquid alloys and the extent of segregation reduces with temperature. We as well found that, in addition to the reported understanding that size-factor determines the compositional location of asymmetry of the viscosity isotherm, temperature is an operating parameter that has effect, not only on the composition of asymmetry, but also on the magnitude of asymmetry. In all the properties investigated, the most pronounced effect of temperature (52.9 %) is on the viscosity while the least effect (7.1 %) is on the surface tension. (orig.)

  19. Effect of atomic size on undercoolability of binary solid solution alloy liquids with Zr, Ti, and Hf using electrostatic levitation.

    Science.gov (United States)

    Jeon, S; Kang, D-H; Lee, Y H; Lee, S; Lee, G W

    2016-11-07

    We investigate the relationship between the excess volume and undercoolability of Zr-Ti and Zr-Hf alloy liquids by using electrostatic levitation. Unlike in the case of Zr-Hf alloy liquids in which sizes of the constituent atoms are matched, a remarkable increase of undercoolability and negative excess volumes are observed in Zr-Ti alloy liquids as a function of their compositional ratios. In this work, size mismatch entropies for the liquids were obtained by calculating their hard sphere diameters, number densities, and packing fractions. We also show that the size mismatch entropy, which arises from the differences in atomic sizes of the constituent elements, plays an important role in determining the stabilities of metallic liquids.

  20. Nanoparticles alloying in liquids: Laser-ablation-generated Ag or Pd nanoparticles and laser irradiation-induced AgPd nanoparticle alloying

    Science.gov (United States)

    Semaltianos, N. G.; Chassagnon, R.; Moutarlier, V.; Blondeau-Patissier, V.; Assoul, M.; Monteil, G.

    2017-04-01

    Laser irradiation of a mixture of single-element micro/nanomaterials may lead to their alloying and fabrication of multi-element structures. In addition to the laser induced alloying of particulates in the form of micro/nanopowders in ambient atmosphere (which forms the basis of the field of additive manufacturing technology), another interesting problem is the laser-induced alloying of a mixture of single-element nanoparticles in liquids since this process may lead to the direct fabrication of alloyed-nanoparticle colloidal solutions. In this work, bare-surface ligand-free Ag and Pd nanoparticles in solution were prepared by laser ablation of the corresponding bulk target materials, separately in water. The two solutions were mixed and the mixed solution was laser irradiated for different time durations in order to investigate the laser-induced nanoparticles alloying in liquid. Nanoparticles alloying and the formation of AgPd alloyed nanoparticles takes place with a decrease of the intensity of the surface-plasmon resonance peak of the Ag nanoparticles (at ∼405 nm) with the irradiation time while the low wavelength interband absorption peaks of either Ag or Pd nanoparticles remain unaffected by the irradiation for a time duration even as long as 30 min. The nanoalloys have lattice constants with values between those of the pure metals, which indicates that they consist of Ag and Pd in an approximately 1:1 ratio similar to the atomic composition of the starting mixed-nanoparticle solution. Formation of nanoparticle networks consisting of bimetallic alloyed nanoparticles and nanoparticles that remain as single elements (even after the end of the irradiation), joining together, are also formed. The binding energies of the 3d core electrons of both Ag and Pd nanoparticles shift to lower energies with the irradiation time, which is also a typical characteristic of AgPd alloyed nanoparticles. The mechanisms of nanoparticles alloying and network formation are also

  1. Nanoparticles alloying in liquids: Laser-ablation-generated Ag or Pd nanoparticles and laser irradiation-induced AgPd nanoparticle alloying.

    Science.gov (United States)

    Semaltianos, N G; Chassagnon, R; Moutarlier, V; Blondeau-Patissier, V; Assoul, M; Monteil, G

    2017-04-18

    Laser irradiation of a mixture of single-element micro/nanomaterials may lead to their alloying and fabrication of multi-element structures. In addition to the laser induced alloying of particulates in the form of micro/nanopowders in ambient atmosphere (which forms the basis of the field of additive manufacturing technology), another interesting problem is the laser-induced alloying of a mixture of single-element nanoparticles in liquids since this process may lead to the direct fabrication of alloyed-nanoparticle colloidal solutions. In this work, bare-surface ligand-free Ag and Pd nanoparticles in solution were prepared by laser ablation of the corresponding bulk target materials, separately in water. The two solutions were mixed and the mixed solution was laser irradiated for different time durations in order to investigate the laser-induced nanoparticles alloying in liquid. Nanoparticles alloying and the formation of AgPd alloyed nanoparticles takes place with a decrease of the intensity of the surface-plasmon resonance peak of the Ag nanoparticles (at ∼405 nm) with the irradiation time while the low wavelength interband absorption peaks of either Ag or Pd nanoparticles remain unaffected by the irradiation for a time duration even as long as 30 min. The nanoalloys have lattice constants with values between those of the pure metals, which indicates that they consist of Ag and Pd in an approximately 1:1 ratio similar to the atomic composition of the starting mixed-nanoparticle solution. Formation of nanoparticle networks consisting of bimetallic alloyed nanoparticles and nanoparticles that remain as single elements (even after the end of the irradiation), joining together, are also formed. The binding energies of the 3d core electrons of both Ag and Pd nanoparticles shift to lower energies with the irradiation time, which is also a typical characteristic of AgPd alloyed nanoparticles. The mechanisms of nanoparticles alloying and network formation are also

  2. Thermodynamics of solid and liquid group III-V alloys

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, T.J.

    1978-10-01

    Solid-state electrochemical techniques are applied to the Ga-In-Sb-O system to measure some thermodynamic properties important for the analysis of solid-liquid phase equilibria in these important semiconductor materials. The standard Gibbs energies of formation of the most stable oxides of gallium and of indium are determined with a high-temperature solid-state electrochemical cell utilizing calcia-stabilized zirconia as the solid electrolyte and a (CO + CO/sub 2/) gaseous mixture as the reference electrode.

  3. Solidification of Liquid Distributed in its Primary Matrix Phase of Al-10Cu-Fe Alloy and Their Tribological Characteristics

    Science.gov (United States)

    Rao, L. Sankara; Jha, A. K.; Ojha, S. N.

    2016-12-01

    Solidification behavior of liquid phase entrained in its primary solid has been investigated. A hypoeutectic alloy based on Al-Cu-Fe system containing Fe and Si was thermal cycled between semisolid regions to low temperatures. The freezing characteristics of the liquid were recorded in inverse rate cooling curves. The continuous network of the liquid phase progressively changed into isolated droplets with their different size and size distribution. Such droplets revealed undercooling of the melt varying from 20 to 35 °C below the eutectic temperature of the alloy. This behavior of melt undercooling is discussed in light of independent nucleation events associated with freezing of droplets. Solidification structure of droplets revealed particulate eutectic phases in contrast to lamellar eutectic microstructure in the interdendritic region of the as-cast alloy. The droplet distribution and their solidification structure resulted in an improvement in tribological characteristics of the alloy. This effect is correlated with features of wear surfaces generated on the matting surfaces.

  4. Electrical properties of liquid Cd-Te alloys

    Science.gov (United States)

    Moussa, A. Ben; Giordanengo, B.; Humbert, J. C.; Chaaba, H.; Bestandji, M.; Gasser, J. G.

    2000-12-01

    The electrical resistivity and the thermopower of liquid Cdx-Te1-x have been investigated experimentally as a function of temperature over the whole composition range. Due to the high melting point of Cd0.5Te0.5(1098 °C) and the low boiling points of cadmium (765 °C) and tellurium (990 °C), the measurements were difficult. Nevertheless, with a different experimental setup we were able to measure the resistivity and the thermopower from the liquidus up to 1200 °C. The resistivity shows a maximum at x=0.54 reaching a value of 13 000 μΩ cm at 1100 °C. A marked feature of liquid Cdx-Te1-x is that the thermopower varies rapidly from a positive value in the tellurium rich region to a negative value in the cadmium rich one around the equiatomic composition. The electronic properties, near this composition, were analyzed by using equations derived from the Kubo-Greenwood formula.

  5. Liquid Iron Alloys with Hydrogen at Outer Core Conditions by First Principles

    Science.gov (United States)

    Umemoto, K.; Hirose, K.

    2015-12-01

    Since the density of the outer core deduced from seismic data is about 10% lower than that of pure iron at core pressures and temperatures (P-T), it is widely believed that the outer core includes one or more light elements. Although intensive experimental and theoretical studies have been performed so far, the light element in the core has not yet been identified. Comparison of the density and sound velocity of liquid iron alloys with observations, such as the PREM, is a promising way to determine the species and quantity of light alloying component(s) in the outer core. Here we report the results of a first-principles molecular dynamics study on liquid iron alloyed with hydrogen, one of candidates of the light elements. Hydrogen had been much less studied than other candidates. However, hydrogen has been known to reduce the melting temperature of Fe-H solid [1]. Furthermore, very recently, Nomura et al. argued that the outer core may include 24 at.% H in order to be molten under relatively low temperature (attracted strong interests. We clarify the effects of hydrogen on density and sound velocity of liquid iron alloys under outer core P-T conditions. It is shown that ~1 wt% hydrogen can reproduce PREM density and sound velocity simultaneously very well. In addition, we show the presence of hydrogen rather reduces Gruneisen parameters. It indicates that, if hydrogen exists in the outer core, temperature profile of the outer core could be changed considerably from one estimated so far. [1] Sakamaki, K., E. Takahashi, Y. Nakajima, Y. Nishihara, K. Funakoshi, T. Suzuki, and Y. Fukai, Phys. Earth Planet. Inter., 174, 192-201 (2009). [2] Nomura, R., K. Hirose, K. Uesugi, Y. Ohishi, A. Tsuchiyama, A. Miyake, and Y. Ueno, Science 31, 522-525 (2014).

  6. Centrifugal Infiltration of Porous Ceramic Preforms by the Liquid Al Alloy – Theoretical Background and Experimental Verification

    Directory of Open Access Journals (Sweden)

    Dolata A.J.

    2016-03-01

    Full Text Available The goal of this work is the description of phenomena occurring during centrifugal infiltration of porous ceramic materials by liquid Al alloy. In this method, the pressure required to infiltration of liquid metal into pores of ceramic is generated by centrifugal force. From the beginning it was assumed that the porous ceramic material will create reinforcement layer in specific area of the casting. The forces that influence on the liquid metal during mould centrifugation and heat exchange between ceramic preform and metal alloy within the area of the front of infiltration were considered in the analysis. The paper presents also selected experiment results.

  7. Numerical model of the solidification of alloys with natural convection of the liquid

    Directory of Open Access Journals (Sweden)

    E. Węgrzyn-Skrzypczak

    2008-04-01

    Full Text Available The paper deals with comparison of numerical analysis results obtained for binary alloys solidification process in the sand and permanent mould with motion of the fluid in the liquid and mushy zone. The partial differential equations describing mathematical model of the phenomena are presented. Finite Element Method is used for modeling process. Characteristic Based Split (CBS method is used for solving momentum equation. Such approach allows to uncouple velocities and pressure. Petrov-Galerkin formulation is employed to stabilize heat conductivity equation with convective term. The results of the numerical simulations in the 2D region are discussed. Velocity fields, cooling rates and positions of the liquid, solid-liquid and solid regions are compared.

  8. Liquid Phase 3D Printing for Quickly Manufacturing Metal Objects with Low Melting Point Alloy Ink

    CERN Document Server

    Wang, Lei

    2014-01-01

    Conventional 3D printings are generally time-consuming and printable metal inks are rather limited. From an alternative way, we proposed a liquid phase 3D printing for quickly making metal objects. Through introducing metal alloys whose melting point is slightly above room temperature as printing inks, several representative structures spanning from one, two and three dimension to more complex patterns were demonstrated to be quickly fabricated. Compared with the air cooling in a conventional 3D printing, the liquid-phase-manufacturing offers a much higher cooling rate and thus significantly improves the speed in fabricating metal objects. This unique strategy also efficiently prevents the liquid metal inks from air oxidation which is hard to avoid otherwise in an ordinary 3D printing. Several key physical factors (like properties of the cooling fluid, injection speed and needle diameter, types and properties of the printing ink, etc.) were disclosed which would evidently affect the printing quality. In addit...

  9. Prediction of Activities in Fe-Based Ternary Liquid Alloys by Hoch-Arpshofen Model

    Institute of Scientific and Technical Information of China (English)

    YANGHong—wei; LIANChao; TAODong—ping

    2012-01-01

    Thermodynamic properties for an alloy system play an important role in the materials science and engineer- ing. Therefore, theoretical calculations having the flexibility to deal with complexity are very useful and have scien- tific meaning. The Hoch-Arpshofen model was deduced from physical principles and is applicable to binary, ternary and larger system using its binary interaction parameters only. Calculations of the activities of Fe-based liquid alloys are calculated using Hoch-Arpshofen model from data on the binary subsystems. Results for the activities for Fe-Au- Ni, Fe-Cr-Ni, Fe-Co-Cr and Fe-Co-Ni systems at required temperature are presented by Hoch-Arpshofen model. The average relative errors of prediction are 7.8%, 4.5%, 4.9~ and 2.7%, respectively. It shows that the calcu- lated results are in good agreement with the experimental data except Fe-Au-Ni system, which exhibits strong inter- action between unlike atoms. The model provides a simple, reliable and general method for calculating the activities for Fe-based liquid alloys.

  10. Theoretical means for searching bimetallic alloys as anode electrocatalysts for direct liquid-feed fuel cells

    Science.gov (United States)

    Demirci, Umit B.

    The present paper reviews the best anode electrocatalysts, mainly the alloys, which have been tested in direct liquid-feed fuel cells fed with methanol, ethanol or formic acid. It attempts to interpret the alloys catalytic behaviours by using the Nørskov and co-workers' theoretical work [A. Ruban, B. Hammer, P. Stoltze, H.L. Skriver, J.K. Nørskov, J. Mol. Catal. A 115 (1997) 421; B. Hammer, J.K. Nørskov, Adv. Catal. 45 (2000) 71; J. Greeley, J.K. Nørskov, M. Maurikakis, Annu. Rev. Phys. Chem. 53 (2002) 319], who proposed surface theories and databases about the metals d-band centre shift and the segregation. It also attempts to suggest new alloys combinations. For example, for the methanol oxidation, the best catalyst is Pt-Ru and the following features make this catalyst stand out: the d-band centre of Pt shifts down what supposes weaker molecules adsorption and Pt strongly segregates. From this analysis, it is suggested that the Pd-Ni alloy may be a potentially good catalyst. Similar interpretations are given for the three fuel cell systems regarded in the present paper.

  11. Liquid Supercoolability and Synthesis Kinetics of Quinary Refractory High-entropy Alloy

    Science.gov (United States)

    Wang, W. L.; Hu, L.; Yang, S. J.; Wang, A.; Wang, L.; Wei, B.

    2016-11-01

    The high-entropy configuration of equiatomic multicomponent alloys opens an effective access to the development of advanced materials. Here we report the synthesis of a new quinary refractory WMoTaNbZr high-entropy alloy under electrostatic levitation condition. It showed a high liquidus temperature of 2686 K and achieved a maximum supercooling of 640 K (0.24 TL) at molten state. The containerless measurements revealed a linear increasing tendency for both its liquid state density and the specific heat to emissivity ratio versus alloy supercooling. A high-entropy body-centered cubic (HEB) phase dominated its phase constitution despite the formation of a negligible amount of solid solution (Zr) phase. The dendritic growth of HEB phase always governed the crystallization process, attained a fastest growth velocity of 13.5 m/s and displayed a power function relation to alloy supercooling. The high speed videographic research of recalescence phenomenon indicated Johnson-Mehl-Avrami type transition kinetics for its rapid solidification process. As supercooling increases, the microstructures of primary HEB phase were refined conspicuously and exhibited an obvious solute trapping effect of the segregative Zr component. Meanwhile, the Vickers hardness of HEB phase displayed the rising tendency with supercooling.

  12. Liquid oxygen LOX compatibility evaluations of aluminum lithium (Al-Li) alloys: Investigation of the Alcoa 2090 and MMC weldalite 049 alloys

    Science.gov (United States)

    Diwan, Ravinder M.

    1989-01-01

    The behavior of liquid oxygen (LOX) compatibility of aluminum lithium (Al-Li) alloys is investigated. Alloy systems of Alcoa 2090, vintages 1 to 3, and of Martin Marietta Corporation (MMC) Weldalite 049 were evaluated for their behavior related to the LOX compatibility employing liquid oxygen impact test conditions under ambient pressures and up to 1000 psi. The developments of these aluminum lithium alloys are of critical and significant interest because of their lower densities and higher specific strengths and improved mechanical properties at cryogenic temperatures. Of the different LOX impact tests carried out at the Marshall Space Flight Center (MSFC), it is seen that in certain test conditions at higher pressures, not all Al-Li alloys are LOX compatible. In case of any reactivity, it appears that lithium makes the material more sensitive at grain boundaries due to microstructural inhomogeneities and associated precipitate free zones (PFZ). The objectives were to identify and rationalize the microstructural mechanisms that could be relaxed to LOX compatibility behavior of the alloy system in consideration. The LOX compatibility behavior of Al-Li 2090 and Weldalite 049 is analyzed in detail using microstructural characterization techniques with light optical metallography, scanning electron microscopy (SEM), electron microprobe analysis, and surface studies using secondary ion mass spectrometry (SIMS), electron spectroscopy in chemical analysis (ESCA) and Auger electron spectroscopy (AES). Differences in the behavior of these aluminum lithium alloys are assessed and related to their chemistry, heat treatment conditions, and microstructural effects.

  13. Interatomic potential for the compound-forming Li–Pb liquid alloy

    Energy Technology Data Exchange (ETDEWEB)

    Fraile, Alberto, E-mail: albertofrailegarcia@gmail.com [Instituto de Fusión Nuclear, ETSI Industriales, Universidad Politécnica de Madrid, Jose Gutierrez Abascal 2, 28006 Madrid (Spain); Cuesta-López, Santiago, E-mail: scuesta@ubu.es [Universidad de Burgos, Parque Científico I+D+I, Plaza Misael Bañuelos s/n, 09002 Burgos (Spain); Caro, Alfredo; Schwen, Daniel [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Manuel Perlado, J. [Instituto de Fusión Nuclear, ETSI Industriales, Universidad Politécnica de Madrid, Jose Gutierrez Abascal 2, 28006 Madrid (Spain)

    2014-05-01

    Atomistic simulations of liquid alloys face the challenge of correctly modeling basic thermodynamic properties. In this work we present an interatomic potential for this system, as well as a study of physical properties of Li–Pb alloys. Despite the complexity due to Li–Pb being a compound forming system where charge transfer is expected, we show here how the empirical EAM formalism is able to satisfactorily describe several physical properties in a wide range of Li concentration. Application of our potential to Li–Pb eutectic allows us to correctly predict many physical properties observed experimentally and calculated with ab initio techniques, providing in this way a potential suitable for future studies in the context of tritium breeder blanket designs in Fusion technology.

  14. Intermediate strength alloys for high temperature service in liquid-salt cooled energy systems

    Energy Technology Data Exchange (ETDEWEB)

    Muralidharan, Govindarajan; Wilson, Dane Francis; Holcomb, David Eugene

    2017-06-20

    An alloy consists essentially of, in terms of weight percent: 6 to 8.5 Cr, 5.5 to 13.5 Mo, 0.4 to 7.5 W, 1 to 2 Ti, 0.7 to 0.85 Mn, 0.05 to 0.3 Al, up to to 0.1 Co, 0.08 to 0.5 C, 1 to 5 Ta, 1 to 4 Nab, 1 to 3 Hf, balance Ni. The alloy is characterized by, at 850.degree. C., a yield strength of at least 36 Ksi, a tensile strength of at least 40 Ksi, a creep rupture life at 12 Ksi of at least 72.1 hours, and a corrosion rate, expressed in weight loss [g/(cm2sec)].times.10.sup.-11 during a 1000 hour immersion in liquid FLiNaK at 850.degree. C., in the range of 8 to 25.

  15. Intermediate strength alloys for high temperature service in liquid-salt cooled energy systems

    Energy Technology Data Exchange (ETDEWEB)

    Muralidharan, Govindarajan; Wilson, Dane Francis; Holcomb, David Eugene

    2017-06-20

    An alloy is composed essentially of, in terms of weight percent: 6 to 8.5 Cr, 5.5 to 13.5 Mo, 0.4 to 7.5 W, 1 to 2 Ti, 0.7 to 0.85 Mn, 0.05 to 0.3 Al, 0.08 to 0.5 C, 0 to 1 Nb, with the 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 30 Ksi, a creep rupture life at 12 Ksi of at least 45 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 6 to 39.

  16. Phase separation and rapid solidification of liquid Cu60Fe30Co10 ternary peritectic alloy

    Institute of Scientific and Technical Information of China (English)

    DAI FuPing; CAO ChongDe; WEI BingBo

    2007-01-01

    The metastable liquid phase separation and rapid solidification of Cu60Fe30Co10 ternary peritectic alloy were investigated by using the drop tube technique and the differential scanning calorimetry method. It was found that the critical temperature of metastable liquid phase separation in this alloy is 1623.5 K, and the two separated liquid phases solidify as Cu(Fe,Co) and Fe(Cu,Co) solid solutions, respectively. The undercooling and cooling rate of droplets processed in the drop tube increase with the decrease of their diameters. During the drop tube processing, the structural morphologies of undercooled droplets are strongly dependent on the cooling rate. With the increase of the cooling rate, Fe(Cu,Co) spheres are refined greatly and become uniformly dispersed in the Cu-rich matrix. The calculations of Marangoni migration velocity (VM) and Stokes motion velocity (VS) of Fe(Cu,Co) droplets indicated that Marangoni migration contributes more to the coarsening and congregation of the minor phase during free fall. At the same undercooling, the VM/VS ratio increases drastically as Fe(Cu,Co) droplet size decreases. On the other hand, a larger undercooling tends to increase the VM/VS value for Fe(Cu,Co) droplets with the same size.

  17. Phase separation and rapid solidification of liquid Cu60Fe30Co10 ternary peritectic alloy

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The metastable liquid phase separation and rapid solidification of Cu60Fe30Co10 ternary peritectic alloy were investigated by using the drop tube technique and the differential scanning calorimetry method. It was found that the critical temperature of metastable liquid phase separation in this alloy is 1623.5 K, and the two sepa- rated liquid phases solidify as Cu(Fe,Co) and Fe(Cu,Co) solid solutions, respec- tively. The undercooling and cooling rate of droplets processed in the drop tube increase with the decrease of their diameters. During the drop tube processing, the structural morphologies of undercooled droplets are strongly dependent on the cooling rate. With the increase of the cooling rate, Fe(Cu,Co) spheres are refined greatly and become uniformly dispersed in the Cu-rich matrix. The calculations of Marangoni migration velocity (VM) and Stokes motion velocity (VS) of Fe(Cu,Co) droplets indicated that Marangoni migration contributes more to the coarsening and congregation of the minor phase during free fall. At the same undercooling, the VM/VS ratio increases drastically as Fe(Cu,Co) droplet size decreases. On the other hand, a larger undercooling tends to increase the VM/VS value for Fe(Cu,Co) drop- lets with the same size.

  18. Enthalpy of mixing of liquid Cu-Fe-Hf alloys at 1873 K

    Energy Technology Data Exchange (ETDEWEB)

    Agraval, Pavel; Turchanin, Mikhail [Donbass State Engineering Academy, Kramatorsk (Ukraine). Metallurgical Dept.; Dreval, Liya [Donbass State Engineering Academy, Kramatorsk (Ukraine). Metallurgical Dept.; Materials Science International Services GmbH (MSI), Stuttgart (Germany)

    2016-12-15

    In the ternary Cu-Fe-Hf system, the mixing enthalpies of liquid alloys were investigated at 1873 K using a high-temperature isoperibolic calorimeter. The experiments were performed along the sections x{sub Cu}/x{sub Fe} = 3/1, 1/1 at x{sub Hf} = 0-0.47 and along the section x{sub Cu}/x{sub Fe} = 1/3 at x{sub Hf} = 0-0.13. The limiting partial enthalpies of mixing of undercooled liquid hafnium in liquid Cu-Fe alloys, Δ{sub mix} anti H{sub Hf}{sup ∞}, are (-122 ± 9) kJ mol{sup -1} (section x{sub Cu}/x{sub Fe} = 3/1), (-106 ± 9) kJ mol{sup -1} (section x{sub Cu}/x{sub Fe} = 1/1), and (-105 ± 2) kJ mol{sup -1} (section x{sub Cu}/x{sub Fe} = 1/3). In the investigated composition range, the integral mixing enthalpies are sign-changing. For the integral mixing enthalpy, an analytical expression was obtained by the least squares fit of the experimental results using the Redlich-Kister-Muggianu polynomial.

  19. Structure factors and phonon dispersion in liquid Li0.61Na0.39 alloy

    Indian Academy of Sciences (India)

    Arun Pratap; Kirit N Lad; K G Raval

    2004-08-01

    The phonon spectra for liquid Li and Na have been computed through the phenomenological model of Bhatia and Singh for disordered systems like liquids and glasses and the obtained results have been compared with the available data obtained by inelastic neutron scattering (INS) and inelastic X-ray scattering (IXS) experiments. The effective pair potentials and their space derivatives are important ingredients in the computation of the dispersion curves. The pair potentials are obtained using the pseudo-potential theory. The empty core model proposed by Ashcroft is widely used for pseudo-potential calculations for alkali metals. But, it is thought to be unsuitable for Li because of its simple 1s electronic structure. However, it can be used with an additional term known as Born–Mayer (BM) core term. The influence of the BM core term on the phonon dispersion is discussed. The same pseudo-potential formalism has been employed to obtain the dispersion relation in liquid Li0.61Na0.39 alloy. Apart from the phonon spectra, the Ashcroft–Langreth structure factors in the alloy are derived in the Percus–Yevick approximation.

  20. Corrosion and cracking behaviour of steel and alloys in liquid H{sub 2}S

    Energy Technology Data Exchange (ETDEWEB)

    Longaygue, X. [Institut Francais du Petrole, 1 et 4 avenue de Bois Preau 92852 Rueil-Malmaison (France); Duval, S. [Institut Francais du Petrole, BP no 3, 69390 Vernaison (France)

    2004-07-01

    When oil and gas wells with very high partial pressure of H{sub 2}S, e.g. H{sub 2}S-rich gas, are under production, the presence of liquid H{sub 2}S is highly probable in the process operations. Until now, corrosion engineers and materials designers have paid little attention to this situation because it is rarely encountered in practice. However, such a scenario recently met an increasing interest in the context of the Sprex development, a new H{sub 2}S pre-extraction process used for the treatment of very sour natural gases, which produces the separated acid gases as a liquid phase for re-injection to a disposal reservoir. It is generally accepted that pure liquid H{sub 2}S is not corrosive by itself towards carbon or low alloy steels, but the presence of water in production and reservoir fluids could make this medium much more corrosive, although this latter assumption is poorly documented. The aim of this paper is to present the corrosion and cracking behaviour of a pipeline carbon steel and of corrosion resistant alloys (CRA) (with Cr > 16%) after exposure to the following media: i) liquid H{sub 2}S saturated with water, and ii) liquid H{sub 2}O saturated with H{sub 2}S. For both solutions, the addition of solid sulphur on some specimens was considered to take into account the possible introduction of oxygen into the system, followed by a reaction with H{sub 2}S. The tests were performed at 80 deg. C in a laboratory autoclave where both phases coexisted, using U-bend specimens as well as rectangular corrosion coupons. The main conclusion of this study is that liquid H{sub 2}S is rather less critical for corrosion and cracking of construction alloys than 'classical' sour solutions, like H{sub 2}S-saturated water. As a consequence, the materials selection will be governed by the same criteria, with the following alternatives: i) use of carbon steels in conjunction with corrosion inhibitors, e.g. higher operation expense; or ii) selection of a CRA

  1. First-principles study of the structural and dynamic properties of the liquid and amorphous Li-Si alloys.

    Science.gov (United States)

    Chiang, Han-Hsin; Lu, Jian-Ming; Kuo, Chin-Lung

    2016-01-21

    We have performed density functional theory calculations and ab initio molecular dynamics to investigate the structures and dynamic properties of the liquid and amorphous LixSi alloys over a range of composition from x = 1.0 - 4.8. Our results show that Si atoms can form a variety of covalently bonded polyanions with diverse local bonding structures in the liquid alloys. Like in c-LiSi, Si atoms can form a continuous bond network in liquid Li1.0Si at 1050 K, while it gradually disintegrates into many smaller Si polyanions as the Li content increases in the alloys. The average sizes of Si polyanions in these liquid alloys were found to be relatively larger than those in their crystalline counterparts, which can even persist in the highly lithiated Li4.81Si alloy at 1500 K. Our results also show that amorphous LixSi alloys have similar local bonding structures but a largely increased short-range order as compared to their liquid counterparts. The differences between the average coordination number of each atomic pair in amorphous solids and that in the liquids are less than 1.1. Furthermore, our calculations reveal that Li and Si atoms can exhibit very distinct dynamic behaviors in the liquids and their diffusivities appear to be largely dependent on the chemical composition of the alloys. The diffusivity of Li was found to increase with the Li content in the alloys primarily because of the reduced interactions between Li and Si atoms, while the Si diffusivity also increases due to the gradual disintegration of the strongly interconnected Si bond network. The diffusivity of Li in amorphous LixSi was predicted to lie in the range between 10(-7) and 10(-9) cm(2)/s at 300 K, which is more than 20-fold larger than that of Si over the composition range considered. Our calculations further show that the diffusivities of both Li and Si can increase by two orders of magnitude as x increases from 1.0 to 3.57 in amorphous LixSi, indicating a more profound dependence on the

  2. First-principles study of the structural and dynamic properties of the liquid and amorphous Li–Si alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, Han-Hsin; Kuo, Chin-Lung, E-mail: chinlung@ntu.edu.tw [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Lu, Jian-Ming [National Center for High-Performance Computing, Tainan 74147, Taiwan (China)

    2016-01-21

    We have performed density functional theory calculations and ab initio molecular dynamics to investigate the structures and dynamic properties of the liquid and amorphous Li{sub x}Si alloys over a range of composition from x = 1.0 − 4.8. Our results show that Si atoms can form a variety of covalently bonded polyanions with diverse local bonding structures in the liquid alloys. Like in c-LiSi, Si atoms can form a continuous bond network in liquid Li{sub 1.0}Si at 1050 K, while it gradually disintegrates into many smaller Si polyanions as the Li content increases in the alloys. The average sizes of Si polyanions in these liquid alloys were found to be relatively larger than those in their crystalline counterparts, which can even persist in the highly lithiated Li{sub 4.81}Si alloy at 1500 K. Our results also show that amorphous Li{sub x}Si alloys have similar local bonding structures but a largely increased short-range order as compared to their liquid counterparts. The differences between the average coordination number of each atomic pair in amorphous solids and that in the liquids are less than 1.1. Furthermore, our calculations reveal that Li and Si atoms can exhibit very distinct dynamic behaviors in the liquids and their diffusivities appear to be largely dependent on the chemical composition of the alloys. The diffusivity of Li was found to increase with the Li content in the alloys primarily because of the reduced interactions between Li and Si atoms, while the Si diffusivity also increases due to the gradual disintegration of the strongly interconnected Si bond network. The diffusivity of Li in amorphous Li{sub x}Si was predicted to lie in the range between 10{sup −7} and 10{sup −9} cm{sup 2}/s at 300 K, which is more than 20-fold larger than that of Si over the composition range considered. Our calculations further show that the diffusivities of both Li and Si can increase by two orders of magnitude as x increases from 1.0 to 3.57 in amorphous Li

  3. 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.

  4. Interfacial reactions between solid Ni and liquid Sn-Zn alloys

    Directory of Open Access Journals (Sweden)

    Gandova V.

    2015-01-01

    Full Text Available The limitation of the harmful lead-containing solders used in the electronics and other industry applications change lead with another metals. Interfacial reactions between Sn-Zn alloys and Ni substrate after annealing at 400 and 450°C were studied. Three intermetallic compounds Ni3Sn4, T1, γ-Ni5Zn21 and liquid Sn were observed in the Ni/Sn-Zn diffusion couples. Scanning electron microscope was used for the investigation of the microstructure. The microhardness measurement of the intermetallic layers was also performed.

  5. Atomic transport properties of Ag xSn 1-x liquid binary alloys

    Science.gov (United States)

    Bhuiyan, E. H.; Ziauddin Ahmed, A. Z.; Bhuiyan, G. M.; Shahjahan, M.

    2008-05-01

    Atomic transport properties, in particular the shear viscosity and diffusion constants for Ag xSn 1-x less simple liquid binary alloys are theoretically studied from a statistical mechanical theory called the distribution function method. The essential ingredients of this theory are the interionic interaction and the pair distribution function for hard spheres. The interionic interaction are described from a local pseudopotential model and the effective hard sphere diameters are obtained from the thermodynamic perturbative method known as the linearized Weeks-Chandler-Andersen (LWCA). Results of calculations for shear viscosities agree well with the available experimental data.

  6. Mephisto - Research equipment for the study of solid/liquid interface destabilization in metal alloys

    Science.gov (United States)

    Favier, J. J.; Malmejac, Y.; Praizey, J. P.; Cambon, G.; Barillot, R.; Changeart, F. J.

    1982-09-01

    Preliminary results of a feasiblity study of space apparatus intended for solid/liquid destabilization in metal alloys, the Mephisto project, are presented. The phenomena that Mephisto will observe, the parameters it will measure, and the scientific studies that it will perform are stated. A general description is given of the instrument, its experimental tubes, and the experiment process. The environmental and thermal constraints, electrical characteristics, and the characteristics of the different signals are outlined. Finally, the requirements of the payload interfaces on which the equipment will be mounted are set forth, including mechanical/geometrical interfaces, thermal interfaces, and electrical interfaces.

  7. Design and testing of electrochemical oxygen sensors for service in liquid lead alloys

    Energy Technology Data Exchange (ETDEWEB)

    Schroer, Carsten, E-mail: carsten.schroer@kit.edu [Karlsruher Institut fuer Technologie (KIT), Institut fuer Angewandte Materialien - Werkstoffprozesstechnik (IAM-WPT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Konys, Juergen [Karlsruher Institut fuer Technologie (KIT), Institut fuer Angewandte Materialien - Werkstoffprozesstechnik (IAM-WPT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Verdaguer, Ariadna; Abella, Jordi [Universitat Ramon Llull, Institut Quimic de Sarria (IQS), Via Augusta, 390, 08017 Barcelona (Spain); Gessi, Alessandro [Agenzia nazionale per le nuove tecnologie, l' energia e lo sviluppo economico sostenibile (ENEA), Centro ricercho Brasimone, FISING, 40032 Camugnano (Bologna) (Italy); Kobzova, Alena; Babayan, Stella [Nuclear Research Institute Rez plc (NRI), Division of Integrity and Technical Engineering, Husinec-Rez 130, 250 68 Rez (Czech Republic); Courouau, Jean-Louis [CEA, DEN, DPC, SCCME, Laboratoire d' Etude de la Corrosion Non Aqueuse, F-91191 Gif-sur-Yvette (France)

    2011-08-31

    Electrochemical oxygen sensors currently used for measuring the chemical potential of oxygen in liquid lead alloys were investigated by five European laboratories, focussing on factors influencing the accuracy of the sensor output, the long-term performance in experimental facilities and methods of testing the sensors before installation and during operation in a plant. The design of different electrochemical oxygen sensors is introduced, along with the experimentally determined sensor reliability and appropriate testing methods. The reported results summarize the results of Task 4.2.4 within Domain 4 (DEMETRA) of the integrated project (IP) EUROTRANS that was funded by the EURATOM 6th Framework Programme.

  8. Multi-Scale Study of the Static Structure of Liquid Li70-Bi30 Alloy

    Directory of Open Access Journals (Sweden)

    Bove L.E.

    2011-05-01

    Full Text Available A multi-scale approach is applied to study the static structure of Li70-Bi30 liquid alloy. In order to describe the interatomic interactions in this non-simple metal, we make a set of three empirical pair potentials fit ab-initio computations of the forces and energy in this system. Large scale classical simulations are performed using these fitted potentials from which the partial and total structures are computed. These results are validated by comparison with new experimental neutron data. The partial structure clearly indicates heterocoordination, which is consistent with a marked ionic nature of the bonding, in agreement with earlier electrical resistivity measurements.

  9. Specific heat and related thermophysical properties of liquid Fe-Cu-Mo alloy

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The specific heat and related thermophysical properties of liquid Fe77.5Cu13Mo9.5 monotectic alloy were investigated by an electromagnetic levitation drop calo-rimeter over a wide temperature range from 1482 to 1818 K.A maximum under-cooling of 221 K(0.13 Tm)was achieved and the specific heat was determined as 44.71 J·mol1·K1.The excess specific heat,enthalpy change,entropy change and Gibbs free energy difference of this alloy were calculated on the basis of experimental results.It was found that the calculated results by traditional esti-mating methods can only describe the solidification process under low under-cooling conditions.Only the experimental results can reflect the reality under high undercooling conditions.Meanwhile,the thermal diffusivity,thermal conductivity,and sound speed were derived from the present experimental results.Furthermore,the solidified microstructural morphology was examined,which consists of(Fe)and(Cu)phases.The calculated interface energy was applied to exploring the correlation between competitive nucleation and solidification microstructure within monotectic alloy.

  10. High strength alloys for high temperature service in liquid-salt cooled energy systems

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-01-10

    An essentially cobalt-free alloy consists essentially of, in terms of weight percent: 6.3 to 7.2 Cr, 0.5 to 2 Al, 0 to 5 Fe, 0.7 to 0.8 Mn, 9 to 12.5 Mo, 0 to 6 Ta, 0.75 to 3.5 Ti, 0.01 to 0.25 Nb, 0.2 to 0.6 W, 0.02 to 0.04 C, 0 to 0.001 B, 0.0001 to 0.002 N, balance Ni. The alloy is characterized by a .gamma.' microstructural component in the range of 3 to 17.6 weight percent of the total composition. The alloy is further characterized by, at 850.degree. C., a yield strength of at least 60 Ksi, a tensile strength of at least 70 Ksi, a creep rupture life at 12 Ksi of at least 700 hours, and a corrosion rate, expressed in weight loss [g/(cm.sup.2sec)]10.sup.-11 during a 1000 hour immersion in liquid FLiNaK at 850.degree. C., in the range of 5.5 to 17.

  11. Thermal Diffusivity and Thermal Conductivity of Five Different Steel Alloys in the Solid and Liquid Phases

    Science.gov (United States)

    Wilthan, B.; Schützenhöfer, W.; Pottlacher, G.

    2015-08-01

    The need for characterization of thermophysical properties of steel and nickel-based alloys was addressed in the FFG-Bridge Project 810999 in cooperation with a partner from industry, Böhler Edelstahl GmbH & Co KG. To optimize numerical simulations of production processes, such as remelting or plastic deformation, additional, and more accurate data were necessary for the alloys under investigation. With a fast ohmic pulse heating circuit system, the temperature-dependent specific electrical resistivity, density, and specific heat capacity for a set of five high alloyed steels were measured. Hence, using the Wiedemann-Franz law with a Lorenz number of , the thermal diffusivity and thermal conductivity could be calculated for the solid and liquid phases up to temperatures of 2500 K. This experimental approach is limited by the following requirements for the specimens: they have to be electrically conducting, the melting point has to be high enough for the implemented pyrometric temperature measurement, and one has to be able to draw wires of the material. The latter restriction is technologically challenging with some of the materials being very brittle. For all samples, electrical and temperature signals are recorded and a fast shadowgraph method is used to measure the volume expansion. For each material under investigation, a set of data including the chemical composition, the density at room temperature, solidus and liquidus temperatures, and the change of enthalpy, resistivity, density, thermal conductivity, and thermal diffusivity as a function of temperature is reported.

  12. Specific heat and related thermophysical properties of liquid Fe-Cu-Mo alloy

    Institute of Scientific and Technical Information of China (English)

    WANG HaiPeng; LUO BingChi; CHANG Jian; WEI BingBo

    2007-01-01

    The specific heat and related thermophysical properties of liquid Fe77.5Cu13Mo9.5 monotectic alloy were investigated by an electromagnetic levitation drop calorimeter over a wide temperature range from 1482 to 1818 K. A maximum undercooling of 221 K (0.13 Tm) was achieved and the specific heat was determined as 44.71 J·mol-1·K-1. The excess specific heat, enthalpy change, entropy change and Gibbs free energy difference of this alloy were calculated on the basis of experimental results. It was found that the calculated results by traditional estimating methods can only describe the solidification process under low undercooling conditions. Only the experimental results can reflect the reality under high undercooling conditions. Meanwhile, the thermal diffusivity, thermal conductivity, and sound speed were derived from the present experimental results. Furthermore, the solidified microstructural morphology was examined, which consists of (Fe) and (Cu) phases. The calculated interface energy was applied to exploring the correlation between competitive nucleation and solidification microstructure within monotectic alloy.

  13. High strength alloys for high temperature service in liquid-salt cooled energy systems

    Science.gov (United States)

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

    2017-01-10

    An essentially cobalt-free alloy consists essentially of, in terms of weight percent: 6.3 to 7.2 Cr, 0.5 to 2 Al, 0 to 5 Fe, 0.7 to 0.8 Mn, 9 to 12.5 Mo, 0 to 6 Ta, 0.75 to 3.5 Ti, 0.01 to 0.25 Nb, 0.2 to 0.6 W, 0.02 to 0.04 C, 0 to 0.001 B, 0.0001 to 0.002 N, balance Ni. The alloy is characterized by a .gamma.' microstructural component in the range of 3 to 17.6 weight percent of the total composition. The alloy is further characterized by, at 850.degree. C., a yield strength of at least 60 Ksi, a tensile strength of at least 70 Ksi, a creep rupture life at 12 Ksi of at least 700 hours, and a corrosion rate, expressed in weight loss [g/(cm.sup.2sec)]10.sup.-11 during a 1000 hour immersion in liquid FLiNaK at 850.degree. C., in the range of 5.5 to 17.

  14. Thermodynamic properties of the liquid Ag-Bi-Cu-Sn lead-free solder alloys

    Directory of Open Access Journals (Sweden)

    Garzel G.

    2014-01-01

    Full Text Available The electromotive force measurement method was employed to determine the thermodynamic properties of liquid Ag-Bi-Cu-Sn alloys using solid electrolyte galvanic cells as shown below: Kanthal+Re, Ag-Bi-Cu-Sn, SnO2 | Yttria Stabilized Zirconia | air, Pt, Experiments were made within temperature interval: 950 - 1300K along four composition paths of constant ratios: XAg : XBi : XCu = 1, XAg : (XBi + XCu = 3:2 for XBi = XCu, XBi : (XAg + XCu = 3:2 for XAg = XCu and XCu : (XAg + XBi = 3:2 for XAg = XBi and tin concentration changing from 0.1 to 0.9 mole fractions, every 0.1. Almost all the results were approximated by straight line equations: EMF vs T, and tin activities were then calculated in arbitrary temperature; measurement results were presented by graphs. Unusual activity plot for XBi : (XAg + XCu = 3:2 composition path was most probably caused by miscibility gap detected earlier in Bi-Cu-Sn ternary liquid alloys.

  15. Enthalpies of mixing in binary liquid alloys of lutetium with 3d metals

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Michael; Berezutski, Vadim [National Academy of Sciences, Kyiv (Ukraine). I. Frantsevich Institute for Problems of Materials Science; Usenko, Natalia; Kotova, Natalia [Taras Shevchenko National Univ., Kyiv (Ukraine). Dept. of Chemistry

    2017-01-15

    The enthalpies of mixing in binary liquid alloys of lutetium with chromium, cobalt, nickel and copper were determined at 1 773 - 1 947 K by isoperibolic calorimetry. The enthalpies of mixing in the Lu-Cr melts (measured up to 40 at.% Cr) demonstrate endothermic effects (ΔH = 6.88 ± 0.66 kJ . mol{sup -1} at x{sub Lu} = 0.60), whereas significant exothermic enthalpies of mixing have been established within a wide composition region for the Co-Lu, Ni-Lu and Cu-Lu liquid alloys. Minimum values of the integral enthalpy of mixing are as follows: ΔH{sub min} = -23.57 ± 1.41 kJ . mol{sup -1} at x{sub Lu} = 0.38 for the Co-Lu system; ΔH{sub min} = -48.65 ± 2.83 kJ . mol{sup -1} at x{sub Lu} = 0.40 for the Ni-Lu system; ΔH{sub min} = -24.63 ± 1.52 kJ . mol{sup -1} at x{sub Lu} = 0.37 for the Cu-Lu system.

  16. Low-temperature, vapor-liquid-solid, laterally grown silicon films using alloyed catalysts

    Science.gov (United States)

    LeBoeuf, Jerome L.; Brodusch, Nicolas; Gauvin, Raynald; Quitoriano, Nathaniel J.

    2014-12-01

    Using amorphous oxide templates known as micro-crucibles which confine a vapor-liquid-solid catalyst to a specific geometry, two-dimensional silicon thin-films of a single orientation have been grown laterally over an amorphous substrate and defects within crystals have been necked out. The vapor-liquid-solid catalysts consisted nominally of 99% gold with 1% titanium, chromium, or aluminum, and each alloy affected the processing of micro-crucibles and growth within them significantly. It was found that chromium additions inhibited the catalytic effect of the gold catalysts, titanium changed the morphology of the catalyst during processing and aluminum stabilized a potential third phase in the gold-silicon system upon cooling. Two mechanisms for growing undesired nanowires were identified both of which hindered the VLS film growth, fast silane cracking rates and poor gold etching, which left gold nanoparticles near the gold-vapor interface. To reduce the silane cracking rates, growth was done at a lower temperature while an engineered heat and deposition profile helped to reduce NWs caused by the second mechanism. Through experimenting with catalyst compositions, the fundamental mechanisms which produce concentration gradients across the gold-silicon alloy within a given micro-crucible have been proposed. Using the postulated mechanisms, micro-crucibles were designed which promote high-quality, single crystal growth of semiconductors.

  17. Influence of Liquid Structure on Solid Transformation of CuAlNi Shape Memory Alloy

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Molten Cu-13Al and Cu-13Al-4Ni (mass fraction) alloys have been investigated using X-ray diffraction method.A distinct pre-peak has been found in the structure factors. The pre-peak increases its intensity with decreasing temperature and addition of Ni. The structural unit size corresponding to the pre-peak equals to magnitude of (111)planar distance ofβ phase. The appearance of a pre-peak is due to existence of clusters withβ-phase-like structure in melt. Quantity and size of clusters increase with decreasing temperature but their structural unit size remains constant. Cu-13Al-4Ni shape memory alloy ribbons can be fabricated by rapid solidification technique. Order degree of martensite and temperature of the reverse martensitic transformation increase with decreasing liquid quenching temperature. Β phase particles develop from incorporating and growing of the clusters during solidification, thus result in the correlation between liquid structure and solid transformation.

  18. Diffusion in a liquid alloy - theories and experiments; Diffusion dans un alliage liquide theories et experiences

    Energy Technology Data Exchange (ETDEWEB)

    Chastang, C. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. des Procedes d`Enrichissement]|[Ecole Polytechnique Feminine France (France)

    1997-12-31

    Different theories concerning the calculation of diffusion coefficients in liquid metals, as well for auto as for hetero-diffusion are presented and some experimental procedures using tracer techniques in shear cells and capillary tubes are described. Diffusion curves are calculated with the TRIO-EF code. Calculated and measured values of diffusion coefficients are compared and discussed with regard to various diffusion mechanisms. Copper gadolinium mixtures have been investigated in more detail. (C.B.). 35 refs.

  19. Instability of the Liquid Metal-Pattern Interface in the Lost Foam Casting of Aluminum Alloys

    Science.gov (United States)

    Griffiths, W. D.; Ainsworth, M. J.

    2016-06-01

    The nature of the liquid metal-pattern interface during mold filling in the Lost Foam casting of aluminum alloys was investigated using real-time X-ray radiography for both normal expanded polystyrene, and brominated polystyrene foam patterns. Filling the pattern under the action of gravity from above or below had little effect on properties, both cases resulting in a large scatter of tensile strength values, (quantified by their Weibull Modulus). Countergravity filling at different velocities demonstrated that the least scatter of tensile strength values (highest Weibull Modulus) was associated with the slowest filling, when a planar liquid metal-pattern interface occurred. Real-time X-ray radiography showed that the advancing liquid metal front became unstable above a certain critical velocity, leading to the entrainment of the degrading pattern material and associated defects. It has been suggested that the transition of the advancing liquid metal-pattern interface into an unstable regime may be a result of Saffman-Taylor Instability.

  20. In Situ Observation of MgO Inclusions in Liquid Iron-Aluminum Alloys

    Science.gov (United States)

    Mu, Haoyuan; Zhang, Tongsheng; Yang, Liang; Xavier, Rodrigo R.; Fruehan, Richard J.; Webler, Bryan A.

    2016-08-01

    This study showed that MgO inclusions can be stable in liquid iron with elevated Al and it illustrated an important role of vaporization in the evolution of inclusions. Previous studies have shown that dissolved Al reduces MgO from slags and refractories, leading to spinel (MgAl2O4) inclusions. The elevated Al content of newer steels raises the possibility that MgO inclusions can be stable. In this work, MgO inclusions were produced and observed in an Fe-Al alloy. The inclusions in the liquid alloy at 1873 K (1600 °C) were observed in situ with a Confocal Laser Scanning Microscope (CLSM). Two types of experiments were performed: one where only a metal sample was melted and the other where the sample was in contact with a liquid, MgO-saturated slag. When no slag was present, the MgO inclusions shrank and disappeared at 1873 K (1600 °C). No inclusions were observed in situ during cooling or in post-CLSM analysis. When the MgO-saturated slag was present, the inclusion sizes were essentially constant and MgO was observed on the surface of post-CLSM samples. Analysis of the results showed that MgO can be stable in 1873 K (1600 °C), but that its presence depends on the rate of removal of Mg due to vaporization and the supply of Mg due to slag/metal or refractory/metal reactions.

  1. A comparative first-principles study of the structural and electronic properties of the liquid Li-Si and Li-Ge alloys.

    Science.gov (United States)

    Chiang, Han-Hsin; Kuo, Chin-Lung

    2017-02-14

    We have performed a comparative first-principles study on the structural and electronic properties of the liquid Li1-xSix and Li1-xGex alloys over a range of composition from x = 0.09 to 0.50. Our calculations showed that Si and Ge atoms can exhibit very distinct local bonding characteristics as they were alloyed with the Li atoms in the liquid state, where Si atoms tended to form a variety of covalent bonding configurations while Ge atoms predominantly appeared as the isolated anions in the liquid alloys. These differences in bonding characteristics were reflected in their electronic density of states, in which the liquid Li1-xGex alloys have a lower degree of s-p hybridization with narrower distributions of the 3s and 3p states than the liquid Li1-xSix alloys. Our calculations also showed that the optical conductivities of these two liquid alloys can undergo a transition from the Drude-like metallic nature to the semiconductor-like character as the Si/Ge content increases from 0.09 to 0.22. However, as the Si/Ge content further increases to 0.50, the liquid Li1-xGex alloys may transit to exhibit the Drude-like metallic nature, while the liquid Li1-xSix alloys can still hold the semiconductor-like character. Moreover, our calculations revealed that the dc conductivities of these liquid alloys are predominantly determined by the number of total electronic states at the Fermi level. As the liquid Li1-xSix alloys are within the composition range between 0.20 and 0.50, the increment of the states at the Fermi level with increasing the Si content is nearly identical to the amount of the Li states decreased, leading to an almost unchanged number of total electronic states at the Fermi level. However, since Ge atoms do not favor forming covalent bonding in the liquid alloys to keep the Fermi level at a minimum of the density of states, the liquid Li1-xGex alloys would have more electronic states at the Fermi level and thereby higher dc conductivities than the liquid Li1

  2. Thermodynamic and experimental study of corrosion behavior of vanadium-based alloy in liquid sodium-potassium coolant

    Science.gov (United States)

    Krasin, V. P.; Lyublinski, I. E.; Soyustova, S. I.

    2016-11-01

    A preliminary assessment of oxygen effect on vanadium solubility in Na-K melt eutectic composition has been carried out using mathematical framework of the subregular solution model and equations of coordination-cluster model. The effect of oxygen on the solubility of vanadium in the Na-K alloy can be considered as the result of short-range ordering in liquid metal solution. The negative deviations from the ideality for dilute oxygen solutions in Na-K solvent is one reason that explains the quantitative differences between Na and Na-K coolants, when we need to estimate the threshold oxygen concentration for the formation of ternary oxide NaVO2 on the surface of the solid vanadium in liquid sodium and in Na-K alloy. Isothermal capsule experiments qualitatively confirmed the results of calculations of vanadium solubility in Na0.32K0.68 alloy.

  3. Gibbs free energy difference between the undercooled liquid and the beta phase of a Ti-Cr alloy

    Science.gov (United States)

    Ohsaka, K.; Trinh, E. H.; Holzer, J. C.; Johnson, W. L.

    1992-01-01

    The heat of fusion and the specific heats of the solid and liquid have been experimentally determined for a Ti60Cr40 alloy. The data are used to evaluate the Gibbs free energy difference, delta-G, between the liquid and the beta phase as a function of temperature to verify a reported spontaneous vitrification (SV) of the beta phase in Ti-Cr alloys. The results show that SV of an undistorted beta phase in the Ti60Cr40 alloy at 873 K is not feasible because delta-G is positive at the temperature. However, delta-G may become negative with additional excess free energy to the beta phase in the form of defects.

  4. Newly developed EMF cell with zirconia solid electrolyte for measurement of low oxygen potentials in liquid Cu-Cr and Cu-Zr alloys

    Directory of Open Access Journals (Sweden)

    Katayama I.

    2012-01-01

    Full Text Available In order to measure the very low oxygen potential by use of stabilized zirconia solid electrolyte emf method, a new cell construction was devised. The idea was based on Janke but a zirconia rod was used instead of the zirconia crucible which contacts liquid alloy electrode. The cell was used for determination of the oxygen potentials in liquid dilute Cu-Cr and Cu-Zr alloys. The reference electrode was Cr,Cr2O3. Emf measurements were performed in the temperature range of 1400-1580K and composition range of 0.198-3.10at%Cr-Cu alloys, and 1380-1465K, 0.085-0.761at%Zr-Cu alloys. The composition of liquid alloys were determined by picking up from the liquid alloys and ICP analysis. By use of the newly devised cell construction in this study, stable emf values were obtained at each temperature and alloy composition. Emf values were corrected by using the parameter for electronic contribution of the YSZ. Activity of Cr obeys Henry’s law and activity coefficient at infinitely dilute alloys of Cr in Cu-Cr alloys are: lng0 Cr =(3.80 at 1423K, (3.57 at 1473K, (3.38 at 1523K and (3.20 at 1573K. At 1423 K activity coefficient of Zr at infinitely diluted alloy is lnγo Zr = -4.0.

  5. Microstructure and properties of liquid-phase sintered tungsten heavy alloys by using ultra-fine tungsten powders

    Institute of Scientific and Technical Information of China (English)

    于洋; 王尔德

    2004-01-01

    The microstructure and properties of liquid-phase sintered 93W-4.9Ni-2.1Fe tungsten heavy alloys using ultra-fine tungsten powders (medium particle size of 700 nm) and original tungsten powders (medium particle size of 3 μm) were investigated respectively. Commercial tungsten powders (original tungsten powders) were mechanically milled in a high-energy attritor mill for 35 h. Ultra-fine tungsten powders and commercial Ni, Fe powders were consolidated into green compacts by using CIP method and liquid-phase sintering at 1 465 ℃ for 30 min in the dissociated ammonia atmosphere. Liquid-phase sintered tungsten heavy alloys using ultra-fine tungsten powders exhibit full densification (above 99% in relative density) and higher strength and elongation compared with conventional liquidphase sintered alloys using original tungsten powders due to lower sintering temperature at 1 465 ℃ and short sintering time. The mechanical properties of sintered tungsten heavy alloy are found to be mainly dependent on the particles size of raw tungsten powders and liquid-phase sintering temperature.

  6. Thermodynamic Properties of Liquid Silver-Antimony-Tin Alloys Determined from Electrochemical and Calorimetric Measurements

    Science.gov (United States)

    Łapsa, Joanna; Onderka, Bogusław

    2016-08-01

    The thermodynamic properties of liquid Ag-Sb-Sn alloys were obtained through use of the drop solution calorimetric method and electromotive force (emf) measurements of galvanic cells with a yttria stabilized zirconia (YSZ) solid electrolyte. The experiments were carried out along Ag0.25Sb0.75, Ag0.5Sb0.5 and Ag0.75Sb0.25 sections of the ternary system in the temperature range from 973 K to 1223 K. From the measured emf, the tin activity in liquid solutions of Ag-Sb-Sn was determined for the first time. The partial and integral enthalpy of mixing were determined from calorimetric measurements at two temperatures. These measurements were performed along two cross-sections: Sb0.5Sn0.5 at 912 K and 1075 K, and Ag0.75Sb0.25 at 1075 K. Both experimental data sets were used to find ternary interaction parameters by applying the Redlich-Kister-Muggianu model of the substitutional solution. Consequently, the set of parameters describing the thermodynamic properties of the liquid phase was derived.

  7. Standard test method for tension testing of structural alloys in liquid helium

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This test method describes procedures for the tension testing of structural alloys in liquid helium. The format is similar to that of other ASTM tension test standards, but the contents include modifications for cryogenic testing which requires special apparatus, smaller specimens, and concern for serrated yielding, adiabatic heating, and strain-rate effects. 1.2 To conduct a tension test by this standard, the specimen in a cryostat is fully submerged in normal liquid helium (He I) and tested using crosshead displacement control at a nominal strain rate of 10−3 s−1 or less. Tests using force control or high strain rates are not considered. 1.3 This standard specifies methods for the measurement of yield strength, tensile strength, elongation, and reduction of area. The determination of the elastic modulus is treated in Test Method E 111. Note 1—The boiling point of normal liquid helium (He I) at sea level is 4.2 K (−269°C or −452.1°F or 7.6°R). It decreases with geographic elevation and is...

  8. The solubility of hydrogen in liquid binary Al-Li alloys

    Science.gov (United States)

    Anyalebechi, P. N.; Talbot, D. E. J.; Granger, D. A.

    1988-04-01

    The solubility of hydrogen in liquid binary aluminum alloys with 1, 2, and 3 wt pct lithium has been determined for the temperature range of 913 to 1073 K and pressure 5.3 × 104 to 10.7 × 104 Pa, using an appropriate version of Sieverts’ method. The results fit the Van’t Hoff isobar and Sieverts’ isotherm and the solubility, S, is given by: Al-1 pct Li: log( S/S°) - 1/2 log( P/P°) = -2113/T/k + 2.568 Al-1 pct Li: log( S/S°) - 1/2 log( P/P°) = -2797/T/k + 3.329 Al-1 pct Li: log( S/S°) - 1/2 log( P/P°) = -2889/T/k + 3.508 where S° is a standard value of solubility equal to 1 cm3 of diatomic hydrogen measured at 273 K and 101,325 Pa per 100 g of metal, and P° is a standard pressure equal to 101,325 Pa. Added lithium progressively increases the solubility of hydrogen in liquid aluminum, due more to its effect on the entropy of solution of hydrogen, through its influence on the liquid metal structure than to an increase in the solute hydrogen atom binding enthalpy.

  9. A Novel Vibrating Finger Viscometer for High-Temperature Measurements in Liquid Metals and Alloys

    Science.gov (United States)

    Dubberstein, T.; Schürmann, M.; Chaves, H.; Heller, H.-P.; Aneziris, C. G.

    2016-10-01

    A novel vibrating finger viscometer for high-temperature measurement in liquid metals and alloys up to 1823 K was constructed. The dynamic viscosity (η ) of the liquid fluid is measured as a product of (ρ \\cdot η )^{0.5} and the relative change of the field coil input for a constant amplitude recording at the resonant frequency of the oscillator. The viscometer was calibrated at 298 K using reference silicon oils with varying kinematic viscosities (ν ), (0.79 to 200)× 10^{-6} m2\\cdot s^{-1}. In the present study, the viscosity of liquid gold (99.99 % Au), silver (99.9 % Ag), and tin (99.9 % Sn) was measured. The viscosities expressed as an Arrhenius function of temperature are: {for Au:}quad quad ln η= & {} -0.1990+2669/T {for Ag:} quad quad ln η= & {} -0.4631+2089/T {for Sn:} quad quad ln η= & {} -0.5472+671/T The viscosity values are consistent within the range of available literature data.

  10. Determination of solid-liquid interfacial energies in the In-Bi-Sn ternary alloy

    Energy Technology Data Exchange (ETDEWEB)

    Akbulut, S; Ocak, Y [Department of Physics, Institute of Science and Technology, Erciyes University, Kayseri, 38039 (Turkey); Marasli, N; Keslioglu, K [Department of Physics, Faculty of Arts and Sciences, Erciyes University, Kayseri, 38039 (Turkey); Kaya, H [Department of Science Education, Education Faculty, Erciyes University, Kayseri, 38039 (Turkey); Cadirli, E [Department of Physics, Faculty of Arts and Sciences, Nigde University, Nigde (Turkey)], E-mail: marasli@erciyes.edu.tr

    2008-09-07

    The equilibrated grain boundary groove shapes of solid In{sub 2}Bi solution in equilibrium with the In-Bi-Sn eutectic liquid were observed from a quenched sample at 59 {sup 0}C. The Gibbs-Thomson coefficient, solid-liquid interfacial energy and grain boundary energy of the solid In{sub 2}Bi solution have been determined to be (1.42 {+-} 0.07) x 10{sup -7} K m, (49.6 {+-} 5.0) x 10{sup -3} J m{sup -2} and (97.1 {+-} 10.7) x 10{sup -3} J m{sup -2}, respectively, from the observed grain boundary groove shapes. The thermal conductivities of the solid phases for In-21.23 at% Bi-19.04 at% Sn and In-30.5 at% Bi-3 at% Sn alloys and the thermal conductivity ratio of the liquid phase to the solid phase for In-21.23 at% Bi-19.04 at% Sn have also been measured with a radial heat flow apparatus and a Bridgman type growth apparatus, respectively, at their melting temperature.

  11. Influence of chemical liquids on the fatigue crack growth of the AZ31 magnesium alloy

    Science.gov (United States)

    Wang, Zhang-Zhong; He, Xian-Cong; Bai, Yun-Qiang; Ba, Zhi-Xin; Dai, Yu-Ming; Zhou, Heng-Zhi

    2012-03-01

    The fatigue crack growth behavior of an AZ31 magnesium alloy was investigated by comparing the effect of zirconate and phosphate chemical liquids. The morphology, components, and phase compositions of the chemical depositions at the fatigue crack tip were analyzed by employing scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD), respectively. For samples with and without the chemical liquids, their stress-intensity factor values at the fatigue crack tip were compared by using a stress-strain gauge. The results demonstrated that a zirconate film (Zr x O y ·Zn x O y ) and a phosphate film (Zn3(PO4)2·4H2O and MgZnP2O7) could be formed on the fatigue crack-surface at the fatigue crack tip. The stress distribution was changed because of the chemical depositions and the causticity of the chemical liquids. This could decrease the stress-intensity factor value and thus effectively cause fatigue crack closure, which reduces the fatigue crack growth rate. Moreover, it was found that the fatigue crack closure effect of zirconates was more positive than that of phosphates.

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

    Science.gov (United States)

    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.

  13. Study of surface interactions of ionic liquids with aluminium alloys in corrosion and erosion corrosion processes

    Science.gov (United States)

    Bermúdez, María-Dolores; Jiménez, Ana-Eva; Martínez-Nicolás, Ginés

    2007-06-01

    Surface interactions of alkylimidazolium ionic liquids (ILs) with aluminium alloy Al 2011 have been studied by immersion tests in seven neat ILs [1- n-alkyl-3-methylimidazolium X - (X = BF 4; n = 2 (IL1), 6 (IL2), 8 (IL3). X = CF 3SO 3; n = 2 (IL4). X = (4-CH 3C 6H 4SO 3); n = 2 (IL5). X = PF 6; n = 6 (IL6)] and 1-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide (IL7)]. Immersion tests for Al 2011 have also been carried out in 1 wt.% and 5 wt.% solutions of 1-ethyl,3-methylimidazolium tetrafluoroborate (IL1) in water. No corrosion of Al 2011 by neat ILs is observed. The highest corrosion rate for Al 2011 in water is observed in the presence of a 5 wt.% IL1 due to hydrolysis of the anion with hydrogen evolution and formation of aluminium fluoride. Erosion-corrosion processes have been studied for three aluminium alloys (Al 2011, Al 6061 and Al 7075) in a 90 wt.% IL1 solution in water in the presence of α-alumina particles. The erosion-corrosion rates are around 0.2 mm/year or lower, and increase with increasing copper content to give a corrosion resistance order of Al 6061 > Al 7075 > Al 2011. Results are discussed on the basis of scanning electron microscopy (SEM) observations, energy dispersive spectroscopy (EDS) analysis, X-ray diffraction (XRD) patterns and X-ray photoelectron spectroscopy (XPS) determinations.

  14. 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.

  15. Effect of thermosolutal convection on the solid-liquid interface in Pb-Au alloy

    Science.gov (United States)

    Tewari, S. N.; Chopra, M. A.

    1990-01-01

    Liquid-solid interface distortion in the region of primary dendrite tips has been investigated in directionally solidified Pb-8 wt pct Au alloy. The distortions are caused by thermosolutal convection despite choice of growth conditions which should have been thermally and solutally stabilizing. The convection produces clustering of primary dendrites on a plane perpendicular to the growth direction. It produces a mushy zone, where the primary dendrites do not protrude with a uniform length, across the specimen cross section, resulting in large macrosegregation in the transverse direction. However, little macrosegregation is observed along the growth direction. The mushy zone, with uneven dendrite lengths, forms in the beginning of directional solidification. Its shape and dendrite distribution do not show much change during subsequent solidification. Tip morphologies of primary dendrites, within the dendrite clusters, appear to follow the morphological stability relationship.

  16. Atomic mobility in a ternary liquid Ga-In-Sn alloy of the eutectic composition

    Science.gov (United States)

    Nefedov, D. Yu.; Antonenko, A. O.; Podorozhkin, D. Yu.; Uskov, A. V.; Charnaya, E. V.; Lee, M. K.; Chang, J. L.; Haase, J.; Michel, D.; Kumzerov, Yu. A.; Fokin, A. V.; Samoilovich, M. I.; Bugaev, A. S.

    2017-02-01

    The nuclear spin-lattice relaxation and Knight shift of 71Ga, 69Ga, and 115In nuclei in a ternary liquid gallium-indium-tin alloy of the eutectic composition, which was introduced into pores of an opal matrix and porous glasses with pore sizes of 18 and 7 nm, have been investigated and compared with those for the bulk melt. It has been found that longitudinal relaxation is accelerated and the Knight shift is decreased, depending on the size of pores. The correlation time of the atomic motion has been calculated for the nanostructured melt in porous matrices. It has been shown that the atomic mobility in the melt decreases with decreasing size of pores in the glasses.

  17. Liquid metal alloy ion sources—An alternative for focussed ion beam technology

    Science.gov (United States)

    Bischoff, Lothar; Mazarov, Paul; Bruchhaus, Lars; Gierak, Jacques

    2016-06-01

    Today, Focused Ion Beam (FIB) processing is nearly exclusively based on gallium Liquid Metal Ion Sources (LMIS). But, many applications in the μm- or nm range could benefit from ion species other than gallium: local ion implantation, ion beam mixing, ion beam synthesis, or Focused Ion Beam Lithography (IBL). Therefore, Liquid Metal Alloy Ion Sources (LMAIS) represent a promising alternative to expand the remarkable application fields for FIB. Especially, the IBL process shows potential advantages over, e.g., electron beam or other lithography techniques: direct, resistless, and three-dimensional patterning, enabling a simultaneous in-situ process control by cross-sectioning and inspection. Taking additionally into account that the used ion species influences significantly the physical and chemical nature of the resulting nanostructures—in particular, the electrical, optical, magnetic, and mechanic properties leading to a large potential application area which can be tuned by choosing a well suited LMAIS. Nearly half of the elements of the periodic table are recently available in the FIB technology as a result of continuous research in this area during the last forty years. Key features of a LMAIS are long life-time, high brightness, and stable ion current. Recent developments could make these sources feasible for nano patterning issues as an alternative technology more in research than in industry. The authors will review existing LMAIS, LMIS other than Ga, and binary and ternary alloys. These physical properties as well as the fabrication technology and prospective domains for modern FIB applications will similarly be reviewed. Other emerging ion sources will be also presented and their performances discussed.

  18. CaO insulator and Be intermetallic coatings on V-base alloys for liquid-lithium fusion blanket applications

    Energy Technology Data Exchange (ETDEWEB)

    Park, J.H.; Kassner, T.F. [Argonne National Laboratory, Chicago, IL (United States)

    1996-04-01

    The objective of this study is to develop (a) stable CaO insulator coatings at the Liquid-Li/structural-material interface, with emphasis on electrically insulating coating that prevent adverse MHD-generated currents from passing through the V-alloy wall, and (b) stable Be-V intermetallic coating for first-wall components that face the plasma. Electrically insulating and corrosion-resistant coatings are required at the liquid-Li/structural interface in fusion first-wall/blanket application. The electrical resistance of CaO coatings produced on oxygen-enriched surface layers of V-5%Cr-5%Ti by exposing the alloy to liquid Li that contained 0.5-85 wt% dissolved Ca was measured as a function of time at temperatures between 250 and 600{degrees}C. Crack-free Be{sub 2}V intermetallic coatings were also produced by exposing V-alloys to liquid Li that contained Be as a solute. These techniques can be applied to various shapes (e.g., inside/outside of tubes, complex geometrical shapes) because the coatings are formed by liquid-phase reactions.

  19. Segregation and temperature effect on the atomic structure of Bi{sub 30}Ga{sub 70} liquid alloy

    Energy Technology Data Exchange (ETDEWEB)

    Sbihi, D Es; Grosdidier, B; Gasser, J-G [Laboratoire de Physique des Milieux Denses, Institut de Chimie Physique et Materiaux, Universite Paul Verlaine-Metz, 1 Boulevard Arago 57078 Metz Cedex 3 (France); Kaban, I; Gruner, S; Hoyer, W [Institute of Physics, Chemnitz University of Technology, D-09107 Chemnitz (Germany)], E-mail: grosdidi@univ-metz.fr

    2009-06-17

    We investigate the structure of liquid monotectic alloy Bi{sub 30}Ga{sub 70} above and below the critical point. The three-dimensional structure at 265 deg. C is modelled by means of the reverse Monte Carlo simulation technique using neutron and x-ray diffraction experimental data. It is shown that atomic segregation on the short-range scale exists in the liquid Bi{sub 30}Ga{sub 70} slightly above the critical temperature (T{sub C} = 262 deg. C). We present also the structure factors of Bi{sub 30}Ga{sub 70} liquid alloy under the critical point at 240 and 230 deg.C obtained with neutron diffraction to highlight the temperature effect in the atomic structure.

  20. Short-range order in ab initio computer generated amorphous and liquid Cu–Zr alloys: A new approach

    Energy Technology Data Exchange (ETDEWEB)

    Galván-Colín, Jonathan, E-mail: jgcolin@ciencias.unam.mx [Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Apartado Postal 70-360, México, D.F. 04510, México (Mexico); Valladares, Ariel A., E-mail: valladar@unam.mx [Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Apartado Postal 70-360, México, D.F. 04510, México (Mexico); Valladares, Renela M.; Valladares, Alexander [Facultad de Ciencias, Universidad Nacional Autónoma de México, Apartado Postal 70-542, México, D.F. 04510, México (Mexico)

    2015-10-15

    Using ab initio molecular dynamics and a new approach based on the undermelt-quench method we generated amorphous and liquid samples of Cu{sub x}Zr{sub 100−x} (x=64, 50, 36) alloys. We characterized the topology of our resulting structures by means of the pair distribution function and the bond-angle distribution; a coordination number distribution was also calculated. Our results for both amorphous and liquids agree well with experiment. Dependence of short-range order with the concentration is reported. We found that icosahedron-like geometry plays a major role whenever the alloys are Cu-rich or Zr-rich disregarding if the samples are amorphous or liquid. The validation of these results, in turn would let us calculate other properties so far disregarded in the literature.

  1. Compatibility of T91 steel with liquid Pb-Bi eutectic alloy at 450 oC

    Directory of Open Access Journals (Sweden)

    Zhang Yutuo

    2014-05-01

    Full Text Available Pb-Bi eutectic alloy has been receiving increasing attention as a heavy liquid metal coolant in accelerator driven systems and Generation IV fission reactors. Compatibility of structural materials with liquid Pb-Bi eutectic alloy at high temperature is one of the issues concerned. In the present study, corrosion tests of T91 steel in stagnant Pb-Bi eutectic alloy in saturated oxygen condition at 450 篊 were carried out. After experiments, the thickness and compositional profile of the oxide layer on the specimen were analyzed using SEM and EDX. Analysis results show that the thickness of the oxide layer increases as the exposure time increases from 500 h to 1,000 h. The thickness of the oxide layer remains almost unchanged at 15 to 16 mm from 1,000 to 1,500 h. Formation of a thick and protective oxide layer at 450 oC prevents the penetration of liquid Pb-Bi eutectic alloy into the matrix of the T91 steel.

  2. CaO insulator coatings on a vanadium-base alloy in liquid 2 at.% calcium-lithium

    Energy Technology Data Exchange (ETDEWEB)

    Park, J.H.; Kassner, T.F. [Argonne National Laboratory, IL (United States)

    1996-10-01

    The electrical resistance of CaO coatings produced on V-4%Cr-4%Ti and V-15%Cr-5%Ti by exposure of the alloy (round bottom samples 6-in. long by 0.25-in. dia.) to liquid lithium that contained 2 at.% dissolved calcium was measured as a function of time at temperatures between 300-464{degrees}C. The solute element, calcium in liquid lithium, reacted with the alloy substrate at these temperatures for 17 h to produce a calcium coating {approx}7-8 {mu}m thick. The calcium-coated vanadium alloy was oxidized to form a CaO coating. Resistance of the coating layer on V-15Cr-5Ti, measured in-situ in liquid lithium that contained 2 at.% calcium, was 1.0 x 10{sup 10} {Omega}-cm{sup 2} at 300{degrees}C and 400 h, and 0.9 x 10{sup 10} {Omega}-cm{sup 2} at 464{degrees}C and 300 h. Thermal cycling between 300 and 464{degrees}C changed the resistance of the coating layer, which followed insulator behavior. Examination of the specimen after cooling to room temperature revealed no cracks in the CaO coating. The coatings were evaluated by optical microscopy, scanning electron microscopy (SEM), electron dispersive spectroscopy (EDS), and X-ray analysis. Adhesion between CaO and vanadium alloys was enhanced as exposure time increased.

  3. Experimental and molecular dynamics simulation study of structure of liquid and amorphous Ni62Nb38 alloy

    Science.gov (United States)

    Zhang, Y.; Ashcraft, R.; Mendelev, M. I.; Wang, C. Z.; Kelton, K. F.

    2016-11-01

    The state-of-the-art experimental and atomistic simulation techniques were utilized to study the structure of the liquid and amorphous Ni62Nb38 alloy. First, the ab initio molecular dynamics (AIMD) simulation was performed at rather high temperature where the time limitations of the AIMD do not prevent to reach the equilibrium liquid structure. A semi-empirical potential of the Finnis-Sinclair (FS) type was developed to almost exactly reproduce the AIMD partial pair correlation functions (PPCFs) in a classical molecular dynamics simulation. This simulation also showed that the FS potential well reproduces the bond angle distributions. The FS potential was then employed to elongate the AIMD PPCFs and determine the total structure factor (TSF) which was found to be in excellent agreement with X-ray TSF obtained within the present study demonstrating the reliability of the AIMD for the simulation of the structure of the liquid Ni-Nb alloys as well as the reliability of the developed FS potential. The glass structure obtained with the developed potential was also found to be in excellent agreement with the X-ray data. The analysis of the structure revealed that a network of the icosahedra clusters centered on Ni atoms is forming during cooling the liquid alloy down to Tg and the Nb Z14, Z15, and Z16 clusters are attached to this network. This network is the main feature of the Ni62Nb38 alloy and further investigations of the properties of this alloy should be based on study of the behavior of this network.

  4. Alloy

    Science.gov (United States)

    Cabeza, Sandra; Garcés, Gerardo; Pérez, Pablo; Adeva, Paloma

    2014-07-01

    The Mg98.5Gd1Zn0.5 alloy produced by a powder metallurgy route was studied and compared with the same alloy produced by extrusion of ingots. Atomized powders were cold compacted and extruded at 623 K and 673 K (350 °C and 400 °C). The microstructure of extruded materials was characterized by α-Mg grains, and Mg3Gd and 14H-LPSO particles located at grain boundaries. Grain size decreased from 6.8 μm in the extruded ingot, down to 1.6 μm for powders extruded at 623 K (350 °C). Grain refinement resulted in an increase in mechanical properties at room and high temperatures. Moreover, at high temperatures the PM alloy showed superplasticity at high strain rates, with elongations to failure up to 700 pct.

  5. Effect of the third element on the structure of liquid Mg{sub 65}Cu{sub 25}Y{sub 10} alloy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Dan [Key Laboratory for Liquid–Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061 (China); Weihai Wanfeng Magnesium Industry Science and Technology Development Co. Ltd., Weihai 264209 (China); Zhu, Xun Ming [Weihai Wanfeng Magnesium Industry Science and Technology Development Co. Ltd., Weihai 264209 (China); Qin, Jing Yu, E-mail: qinjy@sdu.edu.cn [Key Laboratory for Liquid–Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061 (China); Duan, Jun Peng; Wang, Ai Min [Weihai Wanfeng Magnesium Industry Science and Technology Development Co. Ltd., Weihai 264209 (China); Gu, Ting Kun [School of Electrical Engineering, Shandong University, Jinan 250061 (China)

    2016-08-12

    The liquid structures of Mg{sub 65}Cu{sub 25}Y{sub 10} and its three homologous binary liquid alloys are investigated via ab initio molecular dynamics in the present work. The chemical and topological environments in all four liquid alloys are analyzed using pair distribution function, coordination number, and the Voronoi polyhedron. It shows that the Cu atoms play significant role in deciding the chemical and topological short-range orders of the Mg{sub 65}Cu{sub 25}Y{sub 10} liquid alloy. The Voronoi polyhedra in the ternary liquid alloy illustrate less varieties and longer lifetime. Moreover, the diffusion coefficients are decreased significantly in the ternary liquid alloys according to the mean square displacements. All above offer a deeper insight into how the three species work in the Mg{sub 65}Cu{sub 25}Y{sub 10} liquid alloy. - Highlights: • Cu plays crucial role in Mg{sub 65}Cu{sub 25}Y{sub 10}'s chemical and topological SROs. • Additive elements decrease varieties and prolong lifetimes of Voronoi polyhedra. • Additive elements hinder the diffusion of Mg and Y efficiently.

  6. Efficientcy of corrosion protection properties of epoxy resin/cashew nut shell liquid alloy reinforced with titanium dioxide

    Directory of Open Access Journals (Sweden)

    Wilaivan Loonpooht

    2014-12-01

    Full Text Available The cure behavior of epoxy resin containing cashew nut shell liquid (CNSL and corrosion protective performance of epoxy alloy reinforced with titanium dioxide (TiO2 have been investigated. According to FTIR spectra obtained from epoxy alloys, the CNSL can be employed as a curing agent. The curing process occurred when amount of CNSL was as low as 20%wt. It was found experimentally that the CNSL used for epoxy curing should not be higher than 40%wt.in order to minimize amount CNSL left after reaction. The corrosion protective performance of epoxy alloy on aluminum sheets was carried out. The results revealed that the ability of corrosion resistance increased with the amount of TiO2 introduced into the Epoxy/CNSL film investigated. In this work, the highest corrosion resistance value was found when the TiO2 concentration of 1.5 %wt was reached.

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

    Science.gov (United States)

    Rahman, A. H. M. Esfakur

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

  8. Al and Si Alloying Effect on Solder Joint Reliability in Sn-0.5Cu for Automotive Electronics

    Science.gov (United States)

    Hong, Won Sik; Oh, Chulmin; Kim, Mi-Song; Lee, Young Woo; Kim, Hui Joong; Hong, Sung Jae; Moon, Jeong Tak

    2016-08-01

    To suppress the bonding strength degradation of solder joints in automotive electronics, we proposed a mid-temperature quaternary Pb-free Sn-0.5Cu solder alloy with minor Pd, Al, Si and Ge alloying elements. We manufactured powders and solder pastes of Sn-0.5Cu-(0.01,0.03)Al-0.005Si-(0.006-0.007)Ge alloys (T m = 230°C), and vehicle electronic control units used for a flame-retardant-4 printed circuit board with an organic solderability preservative finish were assembled by a reflow soldering process. To investigate the degradation properties of solder joints used in engine compartments, thermal cycling tests were conducted from -40°C to 125°C (10 min dwell) for 1500 cycles. We also measured the shear strength of the solder joints in various components and observed the microstructural evolution of the solder joints. Based on these results, intermetallic compound (IMC) growth at the solder joints was suppressed by minor Pd, Al and Si additions to the Sn-0.5Cu alloy. After 1500 thermal cycles, IMC layers thicknesses for 100 parts per million (ppm) and 300 ppm Al alloy additions were 6.7 μm and 10 μm, compared to the as-reflowed bonding thicknesses of 6 μm and 7 μm, respectively. Furthermore, shear strength degradation rates for 100 ppm and 300 ppm Al(Si) alloy additions were at least 19.5%-26.2%. The cause of the improvement in thermal cycling reliability was analyzed using the (Al,Cu)-Sn, Si-Sn and Al-Sn phases dispersed around the Cu6Sn5 intermetallic at the solder matrix and bonding interfaces. From these results, we propose the possibility of a mid-temperature Sn-0.5Cu(Pd)-Al(Si)-Ge Pb-free solder for automotive engine compartment electronics.

  9. Transient liquid phase bonding of a third generation gamma-titanium aluminum alloy: Gamma Met PX

    Science.gov (United States)

    Butts, Daniel A.

    The research work presented here discusses transient liquid phase (TLP) bonding of a current (i.e. third) generation gamma-TiAl alloy known as Gamma Met PX (GMPX). Effective implementation of GMPX in service is likely to require fabrication of complicated geometries for which a high performance metallurgical joining technique must be developed. Although a number of joining processes have been investigated, all have significant disadvantages that limit their ability to achieve sound joints. TLP bonding has proved to be a successful method of producing joints with microstructures and compositions similar to that of the bulk substrates. Hence, bonds with parent-like mechanical and oxidation properties are possible. The interlayer and bonding conditions employed for joining of GMPX were based on successful wide-gap TLP joining trials of an earlier generation cast gamma-TiAl alloy with a composition of Ti-48Al-2Cr-2Nb in atomic percent (abbreviated here to 48-2-2). A composite interlayer consisting of a 6:1 weight ratio (7 vol.% copper) of gas atomized 48-2-2 powders (-270 mesh) and pure copper powders (-325 mesh) was employed. When applied to GMPX, these interlayer ratio and bonding conditions produced undesirable microstructures and poor mechanical performance in as-bonded joints. Thus, modifications to the joining technique were required. Initially these modifications were based purely on empirical and phenomenological studies, however, detailed mechanistic studies of the underlying joining mechanisms were conducted to aid in selecting these modifications. Mechanisms such as diffusion, solubility and wettability of copper in/on GMPX and 48-2-2 bulk substrates were investigated and compared. A difference in solubility of copper in GMPX and 48-2-2 bulk substrates was attributed to (at least in part) to the observed differences in GMPX and 48-2-2 bonds. The copper solubility, at the bonding temperature, in the 48-2-2 and GMPX alloys was determined to be ˜2 at.% and ˜1

  10. Interionic pair potentials and partial structure factors of compound-forming quaternary NaSn liquid alloy: First principle approach

    Indian Academy of Sciences (India)

    Anil Thakur; P K Ahluwalia

    2007-10-01

    In this paper formulae for partial structure factors have been used to study partial structure factors of compound-forming quaternary liquid alloys by considering Hoshino's m-component hard-sphere mixture, which is based on Percus-Yevic equation of Hiroike. Formulae are applied to NaSn (Na, Sn, NaSn, Na3Sn) which is considered as a quaternary liquid mixture with the formation of two compounds simultaneously. We have compared the total structure factors for ternary and quaternary alloys with experimental total structure factors which are found to be in good agreement. This suggests that, for suitable stoichiometric composition, two compounds are formed simultaneously. The hard-sphere diameters needed have been calculated using Troullier and Martins ab-initio pseudopotentials.

  11. Chemical short-range order and the Meyer - Neldel rule for liquid alloys: AlCa and GaAlCa

    Science.gov (United States)

    You, D.; Schnyders, H. S.; Van Zytveld, J. B.

    1997-02-01

    We have measured the electrical resistivity, 0953-8984/9/7/006/img1, its specific temperature dependence, 0953-8984/9/7/006/img2, and the thermopower, S, of two series of ternary liquid alloys: 0953-8984/9/7/006/img3 and 0953-8984/9/7/006/img4. We also provide new analysis for the binary liquid alloy AlCa. We do not see the unusually large values for S that were found earlier for amorphous solid ternary alloys of the approximate composition 0953-8984/9/7/006/img5. We do find that, while chemical short-range order (CSRO) appears to occur in the liquid binary alloy 0953-8984/9/7/006/img6, CSRO is apparently destroyed by substitution of one Ga atom for one Al per complex: 0953-8984/9/7/006/img7. CSRO may exist in the liquid alloy 0953-8984/9/7/006/img8. And we find that the activated conductivities of these ternary liquid alloys (and also of liquid AlCa) are consistent with the Meyer - Neldel rule (MNR), extending the range of applicability of the MNR to systems with activation energies about an order of magnitude smaller than previously observed. These results appear to rule out two physical models as universal bases for the MNR, but are consistent with one based on a hopping conductivity whose characteristic energy is that of a polaron shift.

  12. Surface enrichment of Pt in Ga2O3 films grown on liquid Pt/Ga alloys

    Science.gov (United States)

    Grabau, Mathias; Krick Calderón, Sandra; Rietzler, Florian; Niedermaier, Inga; Taccardi, Nicola; Wasserscheid, Peter; Maier, Florian; Steinrück, Hans-Peter; Papp, Christian

    2016-09-01

    The formation of surface Ga2O3 films on liquid samples of Ga, and Pt-Ga alloys with 0.7 and 1.8 at.% Pt was examined using near-ambient pressure (NAP) X-ray photoelectron spectroscopy (XPS). Thickness, composition and growth of the oxide films were deduced as a function of temperature and Pt content of the alloys, in ultra-high vacuum and at oxygen pressures of 3 × 10- 7, 3 × 10- 3 and 1 mbar. We examined oxide layers up to a thickness of 37 Å. Different growth modes were found for oxidation at low and high pressures. The formed Ga2O3 oxide films showed an increased Pt content, while the pristine GaPt alloy showed a surface depletion of Pt at the examined temperatures. Upon growth of Ga2O3 on Pt/Ga alloys a linear increase of Pt content was observed, due to the incorporation of 3.6 at.% Pt in the Ga2O3. The Pt content in Ga2O3, at the examined temperatures and bulk Pt concentrations is found to be independent of pressure, temperature and the nominal Pt content of the metallic alloy.

  13. Short-Range Wetting at Liquid Gallium-Bismuth Alloy Surfaces: X-Ray Measurements and Square-Gradient Theory

    OpenAIRE

    Huber, Patrick; Shpyrko, Oleg; Pershan, Peter S.; Ocko, Ben; DiMasi, Elaine; Deutsch, Moshe

    2003-01-01

    We present an x-ray reflectivity study of wetting at the free surface of the binary liquid metal alloy gallium-bismuth (Ga-Bi) in the region where the bulk phase separates into Bi-rich and Ga-rich liquid phases. The measurements reveal the evolution of the microscopic structure of the wetting films of the Bi-rich, low-surface-tension phase along several paths in the bulk phase diagram. The wetting of the Ga-rich bulk’s surface by a Bi-rich wetting film, the thickness of which is limited by gr...

  14. Measurement of hydrogen solubility and desorption rate in V-4Cr-4Ti and liquid lithium-calcium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Park, J.H.; Erck, R.; Park, E.T. [Argonne National Lab., IL (United States)] [and others

    1997-04-01

    Hydrogen solubility in V-4Cr-4Ti and liquid lithium-calcium was measured at a hydrogen pressure of 9.09 x 10{sup {minus}4} torr at temperatures between 250 and 700{degrees}C. Hydrogen solubility in V-4Cr-4Ti and liquid lithium decreased with temperature. The measured desorption rate of hydrogen in V-4Cr-4Ti is a thermally activated process; the activation energy is 0.067 eV. Oxygen-charged V-4Cr-4Ti specimens were also investigated to determine the effect of oxygen impurity on hydrogen solubility and desorption in the alloy. Oxygen in V-4Cr-4Ti increases hydrogen solubility and desorption kinetics. To determine the effect of a calcium oxide insulator coating on V-4Cr-4Ti, hydrogen solubility in lithium-calcium alloys that contained 0-8.0 percent calcium was also measured. The distribution ratio R of hydrogen between liquid lithium or lithium-calcium and V-4Cr-4Ti increased as temperature decreased (R {approx} 10 and 100 at 700 and 250{degrees}C, respectively). However at <267{degrees}C, solubility data could not be obtained by this method because of the slow kinetics of hydrogen permeation through the vanadium alloy.

  15. The Overcoat Oil Lubrication of Microarc Oxidation Coating on Al Alloy by Liquid Plasma Technique

    Institute of Scientific and Technical Information of China (English)

    LUO Zhuang-zi; ZHANG Zhao-zhu; LIU Wei-ming; WANG Wen-jing; TIAN Jun

    2004-01-01

    Ceramic coatings were deposited on 2Al2 alloy with a 100 kW micro-arc oxidation equipment consisting of a potential adjustable ac power supply and alkali electrolyte. The structure of the micro-arc oxidiation coatings was examined using scanning electron microscopy and transmission electron microscopy. The tribological properties of the coatings sliding against steel under the drop and adsorption lubrication of liquid paraffin were evaluated with a Timken tester. The lower friction coefficient of 0.14 and longer wear life of 2450 m of overcoat were observed for the polished micro-arc oxidation coating of 180μm thick at a sliding speed 2. 50 m/s and load 1500 N. This is because the coating has an interlayer of suitable porosity and thickness, which helps to improve the deposition of lubricants and endure the higher load. In other words, the oil is able to adsorb in the porous holes of the overcoat and provided the lubrication of micro reservoir during friction, and the compact and relatively hard interlayer of oxidation coating is able to support heavy load and prevent the oil lubricating film from damage.

  16. Tape Transfer Printing of a Liquid Metal Alloy for Stretchable RF Electronics

    Directory of Open Access Journals (Sweden)

    Seung Hee Jeong

    2014-09-01

    Full Text Available In order to make conductors with large cross sections for low impedance radio frequency (RF electronics, while still retaining high stretchability, liquid-alloy-based microfluidic stretchable electronics offers stretchable electronic systems the unique opportunity to combine various sensors on our bodies or organs with high-quality wireless communication with the external world (devices/systems, without sacrificing enhanced user comfort. This microfluidic approach, based on printed circuit board technology, allows large area processing of large cross section conductors and robust contacts, which can handle a lot of stretching between the embedded rigid active components and the surrounding system. Although it provides such benefits, further development is needed to realize its potential as a high throughput, cost-effective process technology. In this paper, tape transfer printing is proposed to supply a rapid prototyping batch process at low cost, albeit at a low resolution of 150 μm. In particular, isolated patterns can be obtained in a simple one-step process. Finally, a stretchable radio frequency identification (RFID tag is demonstrated. The measured results show the robustness of the hybrid integrated system when the tag is stretched at 50% for 3000 cycles.

  17. Electromotive force measurements in liquid Ag-In-Pd lead-free alloys

    Institute of Scientific and Technical Information of China (English)

    Grzegorz Garzel; Leszek A. Zabdyr

    2006-01-01

    Emf technique was employed to determine indium activities in the liquid Ag-In-Pd alloys using galvanic cellswith yttria-stabilised-zirconia as solid electrolyte according to the scheme: kanthal/rhenium, Ag-In-Pd, In2O3 | YSZ | Ni, NiO, Pt. Composition and temperature measurement ranges were limited, because of very steep liquidus surface; 35 compositions for XPd up to 0.3 were investigated and at temperatures from near-liquidus up to 1700 K. High temperature experiments required special moly furnace to be constructed with unique automatic gas supply system for furnace winding protective atmosphere. Emf readings were taken and recorded by automatic data acquisition system. Linear dependence of emf on temperature was observed for all compositions investigated, and results were approximated by straight line equations. Then In activities were calculated using well-known relations and taking into account correction for thermoelectric power between kanthal and platinum. Results are to be used along with other existing data to perform assessment of the ternary system under accord.

  18. Thermodynamic properties of liquid silver-gallium alloys determined from e.m.f. and calorimetric measurements

    Energy Technology Data Exchange (ETDEWEB)

    Jendrzejczyk-Handzlik, Dominika, E-mail: djendrze@agh.edu.p [Laboratory of Physical Chemistry and Electrochemistry, Faculty of Non-Ferrous Metals, AGH University of Science and Technology, 30 Mickiewicza Ave., 30-059 Krakow (Poland); Fitzner, Krzysztof [Laboratory of Physical Chemistry and Electrochemistry, Faculty of Non-Ferrous Metals, AGH University of Science and Technology, 30 Mickiewicza Ave., 30-059 Krakow (Poland)

    2011-03-15

    The thermodynamic properties of the liquid Ag-Ga alloys were determined using e.m.f. and calorimetric methods. In the e.m.f. method, solid oxide galvanic cells were used with zirconia electrolyte. The cells of the type W,Ag{sub x}Ga{sub (1-x)},Ga{sub 2}O{sub 3}//ZrO{sub 2}+(Y{sub 2}O{sub 3})//FeO,Fe,W were used in the temperature range from 1098 K to 1273 K, and in the range of mole fraction from x{sub Ga} = 0.1 to x{sub Ga} = 1.0. At first, the Gibbs free energy of formation of pure solid gallium oxide, Ga{sub 2}O{sub 3}, from pure elements was derived. Using values of the measured e.m.f. for the cell with x{sub Ga} = 1.0, the following temperature dependence was obtained: {Delta}{sub f}G{sub m},Ga{sub 2}O{sub 3}{sup 0}({+-}4kJ{center_dot}mol{sup -1}J)=-1061.7235+0.2899T/K. Next, the activity of the gallium was derived as a function of the alloy composition from the values of the measured e.m.f. Activities of silver were calculated using the Gibbs-Duhem equation. The drop calorimetric measurements were carried out at two temperatures, viz. 923 K and 1123 K, using a Setaram MHTC calorimeter. Integral enthalpies of mixing of liquid binary alloys were determined at those temperatures. Finally, thermodynamic properties of the liquid alloys were described with the Redlich-Kister equation using ThermoCalc software.

  19. Friction and wear of selected metals and alloys in sliding contact with AISI 440 C stainless steel in liquid methane and in liquid natural gas

    Science.gov (United States)

    Wisander, D. W.

    1978-01-01

    Aluminum, titanium, beryllium, nickel, iron, copper, and several copper alloys were run in sliding contact with AISI 440C in liquid methane and natural gas. All of the metals run except copper and the copper alloys of tin and tin-lead showed severely galled wear scars. Friction coefficients varied from 0.2 to 1.0, the lowest being for copper, copper-17 wt. % tin, and copper-8 wt. % tin-22 wt. % lead. The wear rate for copper was two orders of magnitude lower than that of the other metals run. An additional order of magnitude of wear reduction was achieved by the addition of tin and/or lead to copper.

  20. Halogen-Free Phosphonate Ionic Liquids as Precursors of Abrasion Resistant Surface Layers on AZ31B Magnesium Alloy

    Directory of Open Access Journals (Sweden)

    Tulia Espinosa

    2015-01-01

    Full Text Available Surface coatings formed by immersion in the ionic liquids (ILs 1,3-dimethylimidazolium methylphosphonate (LMP101, 1-ethyl-3-methylimidazolium methylphosphonate (LMP102 and 1-ethyl-3-methylimidazolium ethylphosphonate (LEP102 on magnesium alloy AZ31B at 50 °C have been studied. The purpose of increasing the temperature was to reduce the immersion time, from 14 days at room temperature, to 48 hours at 50 °C. The abrasion resistance of the coated alloy was studied by microscratching under progressively increasing load, and compared with that of the uncoated material. The order of abrasion resistance as a function of the IL is LEP102 > LMP101 > LMP102, which is in agreement with the order obtained for the coatings grown at room temperature. The maximum reduction in penetration depth with respect to the uncovered alloy, of a 44.5%, is obtained for the sample treated with the ethylphosphonate LEP102. However, this reduction is lower than that obtained when the coating is grown at room temperature. This is attributed to the increased thickness and lower adhesion of the coatings obtained at 50 °C, particularly those obtained from methylphosphonate ionic liquids. The results are discussed from SEM-EDX and profilometry.

  1. 3D structures of liquid-phase GaIn alloy embedded in PDMS with freeze casting.

    Science.gov (United States)

    Fassler, Andrew; Majidi, Carmel

    2013-11-21

    Liquid phase electronic circuits are created by freeze casting gallium-indium (GaIn) alloys, such as eutectic gallium-indium (EGaIn), and encapsulating these frozen components within an elastomer. These metal alloys are liquid at room temperature, and can be cast using either injection or a vacuum to fill a PDMS mold and placing the mold in a freezer. Once solidified, a GaIn alloy segment can be manipulated, altered, or bonded to other circuit elements. A stretchable circuit can be fabricated by placing frozen components onto an elastomer substrate, which can be either patterned or flat, and sealing with an additional layer of elastomer. Circuits produced in this fashion are soft, stretchable, and can have complex 3D channel geometries. In contrast, current fabrication techniques, including needle injection, mask deposition, and microcontact printing, are limited to 2D planar designs. Additionally, freeze casting fabrication can create closed loops, multi-terminal circuits with branching features, and large area geometries.

  2. Effects of Tungsten Addition on the Microstructure and Corrosion Resistance of Fe-3.5B Alloy in Liquid Zinc.

    Science.gov (United States)

    Liu, Xin; Wang, Mengmeng; Yin, Fucheng; Ouyang, Xuemei; Li, Zhi

    2017-04-10

    The effects of tungsten addition on the microstructure and corrosion resistance of Fe-3.5B alloys in a liquid zinc bath at 520 °C were investigated by means of scanning electron microscopy, X-ray diffraction and electron probe micro-analysis. The microstructure evolution in different alloys is analyzed and discussed using an extrapolated Fe-B-W ternary phase diagram. Experimental results show that there are three kinds of borides, the reticular (Fe, W)₂B, the rod-like (Fe, W)₃B and flower-like FeWB. The addition of tungsten can refine the microstructure and improve the stability of the reticular borides. Besides, it is beneficial to the formation of the metastable (Fe, W)₃B phase. The resultant Fe-3.5B-11W (wt %) alloy possesses excellent corrosion resistance to liquid zinc. When tungsten content exceeds 11 wt %, the formed flower-like FeWB phase destroys the integrity of the reticular borides and results in the deterioration of the corrosion resistance. Also, the corrosion failure resulting from the spalling of borides due to the initiation of micro-cracks in the grain boundary of borides is discussed in this paper.

  3. Molar volume, thermal expansion, and bulk modulus in liquid Fe-Ni alloys at 1 bar: Evidence for magnetic anomalies?

    Science.gov (United States)

    Nasch, P. M.; Manghnani, M. H.

    New experimental data on the molar volume Ω, thermal expansion coefficient α, and ultrasonic sound velocity vp in liquid Fe-Ni systems at temperatures between melting and 1975 K are reported. The molar volume and thermal expansion data were acquired using a penetrating γ radiation method; the sound velocity data were obtained by ultrasonic interferometry. In the temperature range of this study, the molar volume Ω increases and the sound velocity vp decreases, both linearly with temperature. The adiabatic bulk modulus KS ∝ v2p/Ωp of liquid Fe-Ni alloys is nearly independent of composition at Fe content greater than 65 wt%. The temperature derivative ∂K/∂T of both adiabatic and isothermal bulk modulus of pure liquid Fe decreases by approximately 50% upon being alloyed with 15 wt% Ni. The mixing behavior of thermodynamic and cohesive properties of liquid Fe-Ni is interpreted as resulting from the existence of disordered and localized magnetic states and correlations in the liquid state, i.e., well above the Curie temperature and extending from pure Fe into the Fe-Ni stability field. These magnetic contributions have strong mechanical effects on the structure in modifying the volume and elastic modulus by as much as 13% and 31%, respectively, in the case of pure liquid Fe. It is believed that the magnetic contribution, which is likely to be absent at core temperatures, should be removed from the measured 1-bar values of density and elastic moduli if these latter were to be used as precise anchoring points in high pressure-temperature EOS.

  4. Influence of Zinc on the Surface Tension, Density and Molar Volume of (Ag-Sneut +Zn Liquid Alloys

    Directory of Open Access Journals (Sweden)

    Gąsior W.

    2016-03-01

    Full Text Available The dilatometric and maximum bubble pressure methods were applied for the measurements of the density and surface tension of liquid (Ag-Sneut +Zn lead-free solders. The experiments were carried out in the temperature range from 515 to 1223 K for the alloys of the zinc concentration equaling 0.01, 0.02, 0.04, 0.05, 0.1 and 0.2 of the mole fraction. It was found that the temperature dependence of both the density and the surface tension could be thought as linear, so they were interpreted by straight line equations. The experimental data of the molar volume of the investigated alloys were described by the polynomial dependent on the composition and temperature.

  5. Molecular dynamics determination of the surface tension of silver-gold liquid alloys and the Tolman length of nanoalloys

    Science.gov (United States)

    Calvo, F.

    2012-04-01

    Using molecular dynamics simulations, an embedded-atom model potential, and the mechanistic route, we have computed the pressure tensor and the surface tension γ of Ag-Au liquid alloys. Although the model generally underestimates γ for pure metals, calculations for a bulk planar slab exhibit nonlinear variations of γ with increasing gold concentration, which agree with experiments and can be accounted for by a perfect solution model. Calculations for various nanoscale droplets containing between 100 and 3200 atoms show a systematic decrease of γ with increasing droplet radius R. The positive Tolman length of the alloy determined from these size variations is estimated to vary slightly with gold concentration. The effects of temperature in the range 1300-1700 K are discussed.

  6. Solid-liquid state pressure bonding of Si3N4 ceramics with aluminum based alloys and its mechanism

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Solid-liquid state pressure bonding of Si3N4 ceramics with aluminum based alloys, which contain a small amount of intermetallic compounds Al3Ti or Al3Zr, was investigated. With this new method, the heat resistant properties of the bonding zone metal are improved, and the joints' strengths at high temperature is increased. The joints' shear strength at room temperature and at 600  ℃ reach 126~133  MPa and 32~34  MPa, respectively, with suitable bonding pressure. The reaction between aluminum and Si3N4 ceramics, which produces Al-Si-N-O type compounds is the dominant interfacial reaction, while the reactions between the second active element Ti or Zr in the aluminum based alloys and Si3N4 ceramics also occur to some extend.

  7. Electrical resistivity and thermal conductivity of liquid Fe alloys at high P and T, and heat flux in Earth's core.

    Science.gov (United States)

    de Koker, Nico; Steinle-Neumann, Gerd; Vlcek, Vojtech

    2012-03-13

    Earth's magnetic field is sustained by magnetohydrodynamic convection within the metallic liquid core. In a thermally advecting core, the fraction of heat available to drive the geodynamo is reduced by heat conducted along the core geotherm, which depends sensitively on the thermal conductivity of liquid iron and its alloys with candidate light elements. The thermal conductivity for Earth's core is very poorly constrained, with current estimates based on a set of scaling relations that were not previously tested at high pressures. We perform first-principles electronic structure computations to determine the thermal conductivity and electrical resistivity for Fe, Fe-Si, and Fe-O liquid alloys. Computed resistivity agrees very well with existing shock compression measurements and shows strong dependence on light element concentration and type. Thermal conductivity at pressure and temperature conditions characteristic of Earth's core is higher than previous extrapolations. Conductive heat flux near the core-mantle boundary is comparable to estimates of the total heat flux from the core but decreases with depth, so that thermally driven flow would be constrained to greater depths in the absence of an inner core.

  8. Liquid Phase Separation and the Aging Effect on Mechanical and Electrical Properties of Laser Rapidly Solidified Cu100−xCrx Alloys

    Directory of Open Access Journals (Sweden)

    Song-Hua Si

    2015-11-01

    Full Text Available Duplex structure Cu-Cr alloys are widely used as contact materials. They are generally designed by increasing the Cr content for the hardness improvement, which, however, leads to the unfavorable rapid increase of the electrical resistivity. The solidification behavior of Cu100−xCrx (x = 4.2, 25 and 50 in wt.% alloys prepared by laser rapid solidification is studied here, and their hardness and electrical conductivity after aging are measured. The results show that the Cu-4.2%Cr alloy has the most desirable combination of hardness and conductive properties after aging in comparison with Cu-25%Cr and Cu-50%Cr alloys. Very importantly, a 50% improvement in hardness is achieved with a simultaneous 70% reduction in electrical resistivity. The reason is mainly attributed to the liquid phase separation occurring in the Cu-4.2%Cr alloy, which introduces a large a

  9. Performance of high speed ball bearings with lead and lead alloy plated retainers in liquid hydrogen at 1.2 million DN

    Science.gov (United States)

    Brewe, D. E.; Scibbe, H. W.; Wisander, D. W.

    1973-01-01

    Ball bearings with lead- and lead-alloy-coated retainers were operated in liquid hydrogen at 30,000 rpm under a thrust load of 400 lb. Bearing lives were compared using different: (1) lead- and lead-alloy coatings, (2) coating thicknesses, (3) substrate materials, (4) retainer locating surfaces, and (5) plating techniques. Longer bearing run times were achieved using retainers with a lead-tin-copper alloy coating electroplated onto a leaded-bronze material and an aluminum-bronze alloy. Thirty percent of the bearings tested achieved the desired objective of 10 hours. All of the lead-alloy coated retainers exceeded this objective. A coating thickness of at least 0.0014 in. was used for all bearings exceeding the 10-hour goal.

  10. Origin of the pre-peak in the structure factor of liquid Fe-4.30C-0.21Ce alloy

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The liquid structure of Fe-4.30C and Fe-4.30C-0.21Ce alloys was studied by high temperature X-ray diffractometer. Theresults show that for Fe-C alloy the nearest neighbor distance of the eutectic alloy is 0.259-0.260 nm at the temperature range of1200-1400℃, which increases to 0.269-0.271 nm with the addition of 0.21% (mass fraction) Ce in the Fe-C alloy at the same tem-perature range. There is a pre-peak at Q = 15.5 nm-1 on the original intensity curve and structure factor S(Q) of the liquid Fe-4.30C-0.21Ce alloy, which was caused by the Ce atoms in the C-Ce clusters. Combined with the shared face, the tetragonal structure canmeet the requirement for the distance of Ce-Ce atoms. It also shows that the cluster size in the liquid Fe-4.30C-0.21Ce alloy in-creases with the decreasing temperature.

  11. Solidification pathways of ternary Cu62.5Fe27.5Sn10 alloy modulated through liquid undercooling and containerless processing

    Science.gov (United States)

    Xia, Z. C.; Wang, W. L.; Wu, Y. H.; Luo, S. B.; Wei, B.

    2016-11-01

    The active control of microstructure evolution is still a challenging factor for the development of advanced immiscible alloys. Here, we make an attempt to modulate the solidification pathways of undercooled Cu62.5Fe27.5Sn10 alloy by glass fluxing and drop tube techniques. Through regulating the liquid undercooling, three types of microstructures, dendrite, dispersive structure and macrosegregation pattern, were formed under the normal gravity condition. Below the first critical undercooling of 15 K, the alloy melt displayed the normal peritectic solidification. At moderate undercoolings above 15 K, the metastable liquid phase separation took place and the solidified microstructure appeared as homogeneously dispersed structure. If undercooling further overtook the second threshold of 107 K, macrosegregation occurred and the bulk alloy separated into an Fe-rich zone and a Cu-rich zone. Under the free fall condition, the alloy droplets with the droplet diameter beyond 805 μm showed the equilibrium peritectic solidification. If the droplet diameter decreased below 805 μm, the metastable liquid phase separation was induced and the microstructural morphology of Cu62.5Fe27.5Sn10 alloy droplet evolved from dendrite into dispersive structure. Furthermore, experimental and simulated results revealed that the temperature gradient had great influence on the size distribution of Fe-rich globules.

  12. Rapid ultrasound-induced transient-liquid-phase bonding of Al-50Si alloys with Zn interlayer in air for electrical packaging application.

    Science.gov (United States)

    Wang, Qian; Chen, Xiaoguang; Zhu, Lin; Yan, Jiuchun; Lai, Zhiwei; Zhao, Pizhi; Bao, Juncheng; Lv, Guicai; You, Chen; Zhou, Xiaoyu; Zhang, Jian; Li, Yuntao

    2017-01-01

    Al-50Si alloys were joined by rapid ultrasound-induced transient-liquid-phase bonding method using Zn foil as interlayer at 390°C in air, below the melt point of interlayer. The fracture of oxide films along the edge of Si particles led to contact and inter-diffusion between aluminum substrate and Zn interlayer, and liquefied Zn-Al alloys were developed. The width of Zn-Al alloys gradually decreased with increasing the ultrasonic vibration time due to liquid squeezing out and accelerated diffusion. A stage of isothermal solidification existed, and the completion time was significantly shortened. In the liquid metal, the acoustic streaming and ultrasonic cavitations were induced. As the process developed, much more Si particles, which were particulate-reinforced phases of Al-50Si, gradually migrated to the center of soldering seam. The highest average shear strength of joints reached to 94.2MPa, and the fracture mainly occurred at the base metal.

  13. Temperature dependence of the liquid eutectic lead-lithium alloy density

    Institute of Scientific and Technical Information of China (English)

    Alchagirov; Boris; B.; Mozgovoi; Alexandr; G.; Taova; Tamara; M.

    2005-01-01

    Lead-lithium alloys are of great interest for practice as the advanced materials to be used in new technique, nuclear energetics, and so forth. Terefore, study on the physico-chemical properties of the latter is of major significance. An analysis of the available literature shows that there are a few works, devoted to study of Pb-Li alloys densities. However, temperature dependence of the density ρ(T), and its temperature coefficientK=dρ/dT for eutectic alloy were obtained by either extrapolation of the density data up to the eutectic alloy's composition, or calculation method. There is a certain discrepancy amounting to as high as 4%, while the allowable error in the density measurements is less than 0.5%. The discrepancy between the results for the temperature coefficients of density amounts to 80%.In this work we present the experimental data on the temperature dependence of Ph0.83 Li0.17 eutectic alloy's density in the temperature range 520K to 643 K. The alloys were prepared using Pb and Li with 99. 999% and 99.8% contents of the basic elements, respectively. We use the improved device, which permits to get the results with error less than 0. 15%. The results of 115 measurements of density in 520K to 643K temperature range were processed by the least-square method. Density polytherm of Pb0.83 Li0. 17 eutectic alloy is described by linear equation ρ(T) =9507.89-0. 79813(T-508) , kg/m3 ,where T is the absolute temperature by K. Mearsurement error was 0. 12% at 95% reliability.Discrepancy in the temperature coefficient data was 1.08%.Thus, the temperature dependence of the Pb-Li eutectic alloy density was studied by the precise two-capillary method. The obtained results may be recommended as the most reliable reference data.

  14. Electrodeposition mechanism and characterization of Ni-Cu alloy coatings from a eutectic-based ionic liquid

    Science.gov (United States)

    Wang, Shaohua; Guo, Xingwu; Yang, Haiyan; Dai, JiChun; Zhu, Rongyu; Gong, Jia; Peng, Liming; Ding, Wenjiang

    2014-01-01

    The electrodeposition mechanism, microstructures and corrosion resistances of Ni-Cu alloy coatings on Cu substrate were investigated in a choline chloride-urea (1:2 molar ratio) eutectic-based ionic liquid (1:2 ChCl-urea IL) containing nickel and copper chlorides. Cyclic voltammetry showed that the onset reduction potentials for Cu (∼-0.32 V) and for Ni (∼-0.47 V) were close to each other, indicating that Ni-Cu co-deposition could be easily achieved in the absence of complexing agent which was indispensable in aqueous plating electrolyte. Chronoamperometric investigations revealed that Ni-Cu deposits followed the three-dimensional instantaneous nucleation/growth mechanism, thus producing a solid solution. The compositions, microstructures and corrosion resistances of Ni-Cu alloy coatings were significantly dependent on the deposition current densities. Ni-Cu alloy coatings were α-Ni(Cu) solid solutions, and the coating containing ∼17.6 at.% Cu exhibited the best corrosion resistance because of its dense and crack-free structure.

  15. Atomic mobility in liquid and fcc Al-Si-Mg-RE (RE = Ce, Sc) alloys and its application to the simulation of solidification processes in RE-containing A357 alloys

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Zhao; Zhang, Lijun [Central South Univ., Changsha (China). State Key Lab of Powder Metallurgy; Tang, Ying [Thermo-Calc Software AB, Solna (Sweden)

    2017-06-15

    This paper first provides a critical review of experimental and theoretically-predicted diffusivities in both liquid and fcc Al-Si-Mg-RE (RE = Ce, Sc) alloys as-reported by previous researchers. The modified Sutherland equation is then employed to predict self- and impurity diffusivities in Al-Si-Mg-RE melts. The self-diffusivity of metastable fcc Sc is evaluated via the first-principles computed activation energy and semi-empirical relations. Based on the critically-reviewed and presently evaluated diffusivity information, atomic mobility descriptions for liquid and fcc phases in the Al-Si-Mg-RE systems are established by means of the Diffusion-Controlled TRAnsformation (DICTRA) software package. Comprehensive comparisons show that most of the measured and theoretically-predicted diffusivities can be reasonably reproduced by the present atomic mobility descriptions. The atomic mobility descriptions for liquid and fcc Al-Si-Mg-RE alloys are further validated by comparing the model-predicted differential scanning calorimetry curves for RE-containing A357 alloys during solidification against experimental data. Detailed analysis of the curves and microstructures in RE-free and RE-containing A357 alloys indicates that both Ce and Sc can serve as the grain refiner for A357 alloys, and that the grain refinement efficiency of Sc is much higher.

  16. A study of early corrosion behaviors of FeCrAl alloys in liquid lead-bismuth eutectic environments

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jun [Nuclear Transmutation Energy Research Center of Korea (NUTRECK), Seoul National University, San 56-1 Shinlim-dong, Gwanak-ku, Seoul 151-742 (Korea, Republic of); Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology, 100 Banyeon-ri, Eonyang-eup, Ulju-gun, Ulsan 689-798 (Korea, Republic of); Nam, Hyo On; Hwang, Il Soon [Nuclear Transmutation Energy Research Center of Korea (NUTRECK), Seoul National University, San 56-1 Shinlim-dong, Gwanak-ku, Seoul 151-742 (Korea, Republic of); Kim, Ji Hyun, E-mail: kimjh@unist.ac.k [Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology, 100 Banyeon-ri, Eonyang-eup, Ulju-gun, Ulsan 689-798 (Korea, Republic of)

    2010-12-31

    Lead and lead-bismuth eutectic (LBE) alloy have been increasingly receiving attention as heavy liquid metal coolants (HLMC) for future nuclear energy systems. The compatibility of structural materials and components with lead-bismuth eutectic liquid at high temperature is one of key issues for the commercialization of lead fast reactors. In the present study, the corrosion behaviors of iron-based alumina-forming alloys (Kanthal-AF (registered) , PM2000, MA956) were investigated by exposing to stagnant LBE environments at 500 {sup o}C and 550 {sup o}C for up to 500 h. After exposures, the thickness and chemistry of the oxide layer on the specimens were analyzed by scanning electron microscopy, scanning transmission electron microscopy and energy dispersive X-ray spectroscopy. As a result, the oxide characteristics and the corrosion resistance were compared. In this study, it was shown that the corrosion resistance of FeCrAl ODS steels (PM2000, MA956) are superior to that of FeCrAl ferritic steel (Kanthal-AF (registered)) in higher temperature LBE.

  17. Characteristics of bulk liquid undercooling and crystallization behaviors of jet electrodeposition Ni–W–P alloy

    Indian Academy of Sciences (India)

    J K Yu; Y H Wang; G Z Xing; Q Qiao; B Liu; Z J Chu; C L Li; F You

    2015-02-01

    The undercooling of Ni–W– P ternary alloy coating melt was investigated by in situ differential scanning calorimeter (DSC) with the flux processing technique. The results showed that the highest undercooling of Ni–W–P ternary alloy with 359 K was obtained as the thermal treatment temperature of themelt being 1679 K and the cooling rate being 50 K min-1. When cooling rate is fixed, the change of undercooling depends on the melt processing temperature, and the undercooling will increase rapidly at the first stage. The effects of thermal treatment temperature and cooling rates on the undercooling were discussed.

  18. Performance of 40-millimeter-bore ball bearings with lead- and lead-alloy-plated retainers in liquid hydrogen at 1.2 million DN

    Science.gov (United States)

    Brewe, D. E.; Wisander, D. W.; Scribbe, H. W.

    1972-01-01

    Forty-millimeter-bore ball bearings with lead- and lead-alloy-coated retainers were operated in liquid hydrogen at 30,000 rpm under a thrust load of 1780 N (400 lb.) Four different substrate materials were used for the retainer. Longer bearing run times were achieved with a lead-tin-copper alloy coating plated onto a leaded-bronze material (22.5 hr) and an aluminum-bronze alloy (19.3 hr). One bearing with a pure lead coating achieved the desired objective of 10 hr. This bearing had an aluminum - bronze substrate retainer and ran successfully for 12.4 hr. Additions of antimony to the lead provided an alloy coating with better wear resistance than pure lead; however, this coating was abrasive to the outer-race lands.

  19. Influence of liquid surface segregation on the pitting corrosion behavior of semi-solid metal high pressure die cast alloy F357

    CSIR Research Space (South Africa)

    Moller, H

    2009-01-01

    Full Text Available Semi-solid metal processing results in liquid segregation at the surface of the components. The pitting behaviour of this surface layer of semi-solid metal processed alloy F357 was compared with the centre (or bulk) of cast plates in 3.5% Na...

  20. Extended superstructures in electron-deficient Zintl-type liquid alloys

    NARCIS (Netherlands)

    Alvarez, M; Verkerk, P; van der Lugt, W

    2002-01-01

    Zintl phases can be distinguished in the so-called Zintl-Klemm compounds and the electron-deficient compounds. In the covalent bonds of the latter an electron may be shared by more than two atoms. Electron-deficient compounds are found among the alkali-group-13 alloys. The bonding type is reflected

  1. Extended superstructures in electron-deficient Zintl-type liquid alloys

    NARCIS (Netherlands)

    Alvarez, M; Verkerk, P; van der Lugt, W

    2002-01-01

    Zintl phases can be distinguished in the so-called Zintl-Klemm compounds and the electron-deficient compounds. In the covalent bonds of the latter an electron may be shared by more than two atoms. Electron-deficient compounds are found among the alkali-group-13 alloys. The bonding type is reflected

  2. A systematic study of segregation for Zn{sub x}Bi{sub 1−x} liquid binary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kasem, Md. Riad; Maruf, Md. Helal Uddin [Department of Physics, University of Dhaka, Dhaka (Bangladesh); Bhuiyan, G. M., E-mail: gbhuiyan@du.ac.bd [Department of Theoretical Physics, University of Dhaka, Dhaka (Bangladesh)

    2015-07-21

    We have investigated the segregating properties of Zn{sub x}Bi{sub 1−x} liquid binary alloys through the thermodynamic route that involves both energy of mixing and entropy of mixing. The perturbation approach is used for effective numerical calculations. Results of our calculations agree well with corresponding experimental data for energy and entropy of mixing in the mixed state. The final prediction of segregating properties such as critical concentration and critical temperature also matches reasonably well with experimental data. Most importantly, both energy of mixing and entropy of mixing have produced almost same values for critical concentration and critical temperature of segregation and thus confirm the reliability of the present approach.

  3. Microstructure and properties of liquid film solution-diffusion welding interface for ZCuBe2.5 Alloy

    Institute of Scientific and Technical Information of China (English)

    徐锦锋; 翟秋亚; 钱翰城

    2004-01-01

    The microstructures and properties of liquid film solution-diffusion welding interface for ZCuBe2.5 alloy have been studied using Cu-base powder. It reveals that the welding joint has high tensile strength up to 278 MPa,rational distribution of hardness and better matches with base materials in properties. Weld metal consists of the uniform and fine α-Cu equiaxed grain and intergranular Cu5.6 Sn phase. The weld is well combined with base materials. The transition solid solution combination interface with a thickness of 150 μm has been formed. In the processof stable welding, the thickness of interface appears to have an increase linearly with bonding time. In the cases of same bonding time, the thickness of interface increases with an increase of temperature gradient, which will become even more apparent with the increase of bonding time.

  4. Model on medium range order in liquid Al-Fe alloys

    Institute of Scientific and Technical Information of China (English)

    秦敬玉; 秦绪波; 王伟民; 边秀房

    2004-01-01

    Numerical analysis confirms that in some cases the prepeak in the structure factor causes obvious change in the coordination number, but change in the interatomic distance can be neglected for the study of the medium range order(MRO). In order to model the MRO, it is not possible to get enough information based on the pair correlation function; however the quasi-Bragg equation can be employed to characterize the quasi-period of MRO corresponding to the prepeak position. By assuming that the interatomic distance between Fe and Al atoms hardly varies with composition, structural models were constructed based on the B2-type structure units of ordered FeAl alloy.The quasi-periods for different alloys obtained from the model structures are in reasonable agreement with the experimental ones.

  5. High Temperature Mass Spectrometry of Liquid Nickel-Aluminum Alloys at 2000 K

    Science.gov (United States)

    1991-05-01

    cmporatlire range 1200 K to 1400 K. Malkin and Pokidyshev 1151 used electromotive force (emf) measurements on a high temperature galvanic cell with a molten...relation. Schaeffer [16] used emf measurements on a high temperature galvanic cell with a molten salt electrolyte to calculate aluminium activities of...measurements on a high temperature galvanic cell with a solid electrolyte to calculate aluminium activities of solid nickel-rich alloys with aluminium

  6. Interactions between drops of molten Al-Li alloys and liquid water

    Energy Technology Data Exchange (ETDEWEB)

    Hyder, M.L. [Westinghouse Savannah River Co., Aiken, SC (United States); Nelson, L.S. [Sandia National Labs., Albuquerque, NM (United States); Duda, P.M.; Hyndman, D.A. [Ktech Corp., Albuquerque, NM (United States)

    1993-08-01

    Sandia National Laboratories, at the request of the Savannah River Technology Center (SRTC), studied the interactions between single drops of molten aluminum-lithium alloys and water. Most experiments were performed with ``B`` alloy (3.1 w/o Li, balance A1). Objectives were to develop experimental procedures for preparing and delivering the melt drops and diagnostics for characterizing the interactions, measure hydrogen generated by the reaction between melt and water, examine debris recovered after the interaction, determine changes in the aqueous phase produced by the melt-water chemical reactions, and determine whether steam explosions occur spontaneously under the conditions studied. Although many H{sub 2} bubbles were generated after the drops entered the water, spontaneous steam explosions never occurred when globules of the ``B`` alloy at temperatures between 700 and 1000C fell freely through water at room temperature, or upon or during subsequent contact with submerged aluminum or stainless steel surfaces. Total amounts of H{sub 2} (STP) increased from about 2 to 9 cm{sup 3}/per gram of melt as initial melt temperature increased over this range of temperatures.

  7. Isoconfigurational elastic constants and liquid fragility of a bulk metallic glass forming alloy.

    Science.gov (United States)

    Lind, Mary Laura; Duan, Gang; Johnson, William L

    2006-07-07

    Samples of Zr(46.25)Ti(8.25)Cu(7.5)Ni(10)Be(27.5) were isothermally annealed and quenched near the glass transition temperature and studied by the pulse-echo overlap technique. The shear modulus G of the samples shows a strong reversible dependence on annealing temperatures and, thus, on the specific configurational potential energy of the equilibrium liquid. The low-T dependence of G of the configurationally frozen glasses shows linear temperature dependence as expected by Debye-Grüneisen theory. The T dependence of G in the liquid state is directly related to the viscosity and fragility of the liquid.

  8. Thermodynamic properties of the liquid Hg-Tl alloys determined from vapour pressure measurements

    Directory of Open Access Journals (Sweden)

    Gierlotka W.

    2002-01-01

    Full Text Available The partial vapour pressure of mercury over liquid Hg-Tl liquid solutions were determined in the temperature range from 450 to 700 K by direct vapour pressure measurements carried out with the quartz gauge. From the measured ln pHg vs. T relationships activities of mercury were determined. Using Redlich-Kister formulas logarithms of the activity coefficients were described with the following equations: From which all thermodynamic functions in the solutions can be derived.

  9. XPS Depth Study on the Liquid Oxidation of Sn-Bi-Zn-X(Al/P) Alloy and the Effect of Al/P on the Film

    OpenAIRE

    Wang, X. J.; Liu, N.; Shi, S.; Chen, Y. X.

    2015-01-01

    X-ray photoelectron spectroscopy (XPS) was used to study the properties of liquid oxidation of Sn-Bi-Zn (SBZ) solder alloys and the effect of Al/P on the oxide film. The results showed that the oxidation film on SBZ surface was in high concentration of both oxygen and zinc. Adding trace amount of Al/P to SBZ alloys (SBZA/ABZP) decreased the ratio of O/M (M could be Sn, Bi, and Al/P) and changed the film compositions. Layers near the free surface of oxidation film mostly contained Zn2+ and Al3...

  10. Experimental and molecular dynamics simulation study of structure of liquid and amorphous Ni 62 Nb 38 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y.; Ashcraft, R.; Mendelev, M. I.; Wang, C. Z.; Kelton, K. F.

    2016-11-28

    The state-of-the-art experimental and atomistic simulation techniques were utilized to study the structure of the liquid and amorphous Ni62Nb38 alloy. First, the ab initio molecular dynamics (AIMD) simulation was performed at rather high temperature where the time limitations of the AIMD do not prevent to reach the equilibrium liquid structure. A semi-empirical potential of the Finnis-Sinclair (FS) type was developed to almost exactly reproduce the AIMD partial pair correlation functions (PPCFs) in a classical molecular dynamics simulation. This simulation also showed that the FS potential well reproduces the bond angle distributions. The FS potential was then employed to elongate the AIMD PPCFs and determine the total structure factor (TSF) which was found to be in excellent agreement with X-ray TSF obtained within the present study demonstrating the reliability of the AIMD for the simulation of the structure of the liquid Ni–Nb alloys as well as the reliability of the developed FS potential. The glass structure obtained with the developed potential was also found to be in excellent agreement with the X-ray data. The analysis of the structure revealed that a network of the icosahedra clusters centered on Ni atoms is forming during cooling the liquid alloy down to Tg and the Nb Z14, Z15, and Z16 clusters are attached to this network. This network is the main feature of the Ni62Nb38 alloy and further investigations of the properties of this alloy should be based on study of the behavior of this network.

  11. The Structure, Dynamics and Electronic Structure of Liquid Ag-Se Alloys Investigated by ab initio Simulation

    CERN Document Server

    Kirchhoff, F; Gillan, M J

    1996-01-01

    Ab initio molecular-dynamics simulations have been used to investigate the structure, dynamics and electronic properties of the liquid alloy Ag(1-x)Se(x) at 1350 K and at the three compositions x=0.33, 0.42 and 0.65. The calculations are based on density-functional theory in the local density approximation and on the pseudopotential plane-wave method. The reliability of the simulations is confirmed by detailed comparisons with very recent neutron diffraction results for the partial structure factors and radial distribution functions (RDF) of the stoichiometric liquid Ag2Se. The simulations show a dramatic change of the Se-Se RDF with increasing Se content. This change is due to the formation of Se clusters bound by covalent bonds, the Se-Se bond length being almost the same as in pure c-Se and l-Se. The clusters are predominantly chain-like, but for higher x a large fraction of 3-fold coordinated Se atoms is also found. It is shown that the equilibrium fractions of Se present as isolated atoms and in clusters...

  12. Correlation between liquid structure and γ2-phase precipitation of Cu-Al-Ni shape memory alloys

    Institute of Scientific and Technical Information of China (English)

    潘学民; 边秀房; 孙景芹; 王伟民

    2002-01-01

    Cu71Al25Ni4 (mole fraction,%) shape memory alloy ribbons exhibit a good shape memory effect, which were prepared by melt-spinning technique. The microstructure of the as-spun ribbons was identified by D/Max-rA X-ray diffractometer. The order degree of martensite increases with decreasing liquid quenching temperature at the same quenching rate. The liquid structure of Cu75Al25 and Cu71Al25Ni4 was investigated using X-ray diffraction method. The distinct pre-peaks have been found in front of main peaks of the structure factors. The pre-peak increases intensity with decreasing temperature or adding Ni. Gaussian peaks decomposing radial distribution function (RDF) indicated that Cu-Al distance is anomalously short. These results suggest that a strong interaction between Cu and Al is favorable to form β-phase-like clusters, which leads to chemical medium-range ordering in melt. This promotes formation of order martensite and suppresses γ2-phase precipitation.

  13. Bulk and surface properties of demixing liquid Al-Sn and Sn-Tl alloys

    Science.gov (United States)

    Odusote, Y. A.; Popoola, A. I.; Oluyamo, S. S.

    2016-02-01

    The energetics of mixing in Al-Sn and Sn-Tl-segregating binary alloys has been explained through the study of surface properties (surface concentrations and surface tension) and various concentration-dependent thermodynamic (free energy of mixing, entropy of mixing and enthalpy of mixing) and transport (chemical diffusion) properties as well as the microscopic functions (concentration fluctuations in the long-wavelength limits and chemical short-range order parameter) using a statistical mechanical theory in conjunction with the self-association model (SAM). The theoretical property values obtained by the SAM were compared to the corresponding experimental values available in literature.

  14. Faceted to non-faceted transition of solid-liquid interface in binary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Yumoto, H.; Hasiguti, R.R.; Kaneko, T.

    1987-03-01

    Jackson's theory on the interfacial roughening transition of pure materials is extended to that of AB binary alloys. In this model, the concept of quasi-dangling bonds is introduced. The bonds are produced by the difference between the number of the interfacial component of nearest neighbors of the A atom and that of the B atom. The roughening temperatures calculated from this model coincide with the faceted - non-faceted transition temperatures obtained experimentally by Miller and Chadwick and by the present authors.

  15. Research perspectives in the field of acoustic treatment of liquid alloys of iron

    Directory of Open Access Journals (Sweden)

    K. Nowacki

    2015-01-01

    Full Text Available One of significant factors affecting properties of steel is uniform distribution of non-metallic inclusions and alloy elements across the steel product cross-section. Acoustic treatment may be the final technological stage enabling the quality of steel to be influenced. Further research to be undertaken in this field should be focused on the design of power heads with application of a stack of several piezoceramic elements or what is referred to as a mosaic head, or consisting in simultaneous use of several heads. What is additionally required is to determine ranges of parameters of the acoustic treatment process for individual groups of steel grades.

  16. Collective Modes and Elastic Constants of Liquid Al83Cu17 Binary Alloy

    Institute of Scientific and Technical Information of China (English)

    B.Y.Thakore; S.G.Khambholja; P.H.Suthar; N.K.Bhatt; A.R.Jani

    2010-01-01

    @@ The collective dynamics(longitudinal and transverse phonon modes)are studied for aluminum-copper(Al-Cu)binary alloy in terms of the eigen-frequencies of the localized collective excitations.The model pseudopotential formalism is employed using a self-consistent phonon scheme by involving multiple scattering and phonon eigenfrequencies.These frequencies are expressed in terms of many-body correlation functions of atoms as well as of interatomic potential.The important ingredients in the present study are the pair-potential and pair-correlation functions.

  17. Viscosity and Electrical Conductivity of the Liquid Sn-3.8Ag-0.7Cu Alloy with Minor Co Admixtures

    Science.gov (United States)

    Yakymovych, A.; Sklyarchuk, V.; Plevachuk, Yu.; Sokoliuk, B.

    2016-10-01

    The viscosity and electrical conductivity as structure-sensitive transport properties of the liquid metals and alloys are important for modeling of the melting and solidification processes. The viscosity and electrical conductivity data provide additional information about the influence of impurities on the structure and physicochemical properties of the liquid metal matrix, which is useful for understanding of structural transformations in the liquid state. In the present work, an impact of minor Co admixtures on the viscosity and electrical conductivity of liquid Sn-3.8Ag-0.7Cu alloy was studied. An increase in viscosity with minor Co admixtures is in a satisfactory agreement with model predicted data obtained from thermodynamic approaches and suggests a significant impact of interatomic interactions. Cobalt admixtures significantly affect the electrical conductivity, which gradually decreases with increasing the amount of Co. Additionally, the sample microstructure has been examined using x-ray diffraction and scanning electron microscopy analyses. The formation of Sn-based Co-Sn intermetallic compounds was detected in the alloys with more than 1 wt.% Co.

  18. Thermal expansion measurements by x-ray scattering and breakdown of Ehrenfest's relation in alloy liquids

    Energy Technology Data Exchange (ETDEWEB)

    Gangopadhyay, A. K.; Blodgett, M. E.; Johnson, M. L.; Vogt, A. J.; Mauro, N. A.; Kelton, K. F. [Department of Physics and Institute of Materials Science and Engineering, Washington University in St. Louis, St. Louis, Missouri 63130 (United States)

    2014-05-12

    Measurements of sharp diffraction peaks as a function of temperature are routinely used to obtain precise linear expansion coefficients of crystalline solids. In this case, the relation between temperature dependent changes in peak position in momentum transfer (q{sub 1}) and volume expansion is straightforward (Ehrenfest's relation: q{sub 1} = K(2π/d), where K is a constant and d is the interatomic spacing) and the data obtained are usually in close agreement with more direct measurements. With high intensity synchrotron x-ray and spallation neutron sources, it is also possible to accurately measure the positions of the much broader peaks for liquids and glasses. This has led to a debate on whether linear expansion coefficients derived from these data are an accurate representation of the volume expansion coefficients. We present here volume thermal expansion and x-ray diffraction data for a large number of glass-forming alloy liquids acquired in a containerless environment using the beamline electrostatic levitation technique. The data show a large difference in the values obtained from the two different techniques. Moreover, the position of the first peak (q{sub 1}) in the scattered intensity in the structure factor (S(q)) and the atomic volume v for all liquids follow a simple relationship, v∝(q{sub 1}){sup −ε}. The exponent, ε = 2.28 (±0.11), is much different from the expected value of 3 from Ehrenfest's relation and shows no temperature dependence over the temperature range of the data collected.

  19. Liquid -to-glass transition in bulk glass-forming Cu55-xZr45Agx alloys using molecular dynamic simulations

    Directory of Open Access Journals (Sweden)

    Celtek M.

    2011-05-01

    Full Text Available We report results from molecular dynamics (MD studies concerning the microscopic structure of the ternary, bulk metallic glass-forming Cu55-x Zr45Agx (x=0,10,20 alloys using tight-binding potentials. Understanding of the nature of Glass Forming Ability (GFA of studied alloys, GFA parameters, glass transition temperature (T-g, melting temperature (T-m, reduced glass transition temperature (T-g/T-m, the supercooled liquid region and other parameters were simulated and compared with experiments. The computed pair distribution functions reproduce well experimental x-ray data of Inoue and co-workers. Structure analysis of the Cu-Zr-Ag alloy based on MD simulation will be also presented

  20. Study of surface interactions of ionic liquids with aluminium alloys in corrosion and erosion-corrosion processes

    Energy Technology Data Exchange (ETDEWEB)

    Bermudez, Maria-Dolores [Grupo de Ciencia de Materiales e Ingenieria Metalurgica, Departamento de Ingenieria de Materiales y Fabricacion, Universidad Politecnica de Cartagena, C/ Doctor Fleming s/n, Campus Muralla del Mar, 30202 Cartagena (Spain)]. E-mail: mdolores.bermudez@upct.es; Jimenez, Ana-Eva [Grupo de Ciencia de Materiales e Ingenieria Metalurgica, Departamento de Ingenieria de Materiales y Fabricacion, Universidad Politecnica de Cartagena, C/ Doctor Fleming s/n, Campus Muralla del Mar, 30202 Cartagena (Spain); Martinez-Nicolas, Gines [Grupo de Ciencia de Materiales e Ingenieria Metalurgica, Departamento de Ingenieria de Materiales y Fabricacion, Universidad Politecnica de Cartagena, C/ Doctor Fleming s/n, Campus Muralla del Mar, 30202 Cartagena (Spain)

    2007-06-30

    Surface interactions of alkylimidazolium ionic liquids (ILs) with aluminium alloy Al 2011 have been studied by immersion tests in seven neat ILs [1-n-alkyl-3-methylimidazolium X{sup -} (X = BF{sub 4}; n = 2 (IL1), 6 (IL2), 8 (IL3). X = CF{sub 3}SO{sub 3}; n = 2 (IL4). X = (4-CH{sub 3}C{sub 6}H{sub 4}SO{sub 3}); n = 2 (IL5). X PF{sub 6}; n = 6 (IL6)] and 1-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide (IL7)]. Immersion tests for Al 2011 have also been carried out in 1 wt.% and 5 wt.% solutions of 1-ethyl,3-methylimidazolium tetrafluoroborate (IL1) in water. No corrosion of Al 2011 by neat ILs is observed. The highest corrosion rate for Al 2011 in water is observed in the presence of a 5 wt.% IL1 due to hydrolysis of the anion with hydrogen evolution and formation of aluminium fluoride. Erosion-corrosion processes have been studied for three aluminium alloys (Al 2011, Al 6061 and Al 7075) in a 90 wt.% IL1 solution in water in the presence of {alpha}-alumina particles. The erosion-corrosion rates are around 0.2 mm/year or lower, and increase with increasing copper content to give a corrosion resistance order of Al 6061 > Al 7075 > Al 2011. Results are discussed on the basis of scanning electron microscopy (SEM) observations, energy dispersive spectroscopy (EDS) analysis, X-ray diffraction (XRD) patterns and X-ray photoelectron spectroscopy (XPS) determinations.

  1. Surface coating from phosphonate ionic liquid electrolyte for the enhancement of the tribological performance of magnesium alloy.

    Science.gov (United States)

    Jiménez, Ana Eva; Rossi, Antonella; Fantauzzi, Marzia; Espinosa, Tulia; Arias-Pardilla, Joaquin; Martínez-Nicolás, Ginés; Bermúdez, María-Dolores

    2015-05-20

    A chronoamperometric method has been applied for the growth of a surface coating on AZ31B magnesium alloy, using the imidazolium alkylphosphonate room-temperature ionic liquid 1-ethyl-3-methylimidazolium ethylphosphonate ([EMIM][EtPO3H]) as electrolyte. A surface coating layer is obtained after 4 h under a constant voltage bias of -0.8 V with respect to the standard electrode. The coating nucleation and growth process correlates well with a 3D progressive mechanism. X-ray photoelectron spectrometry (XPS) analysis of [EMIM][EtPO3H] shows new P 2p and O 1s peaks after its use as electrolyte, as a consequence of reaction between the phosphonate anion and the magnesium substrate. Angle-resolved XPS (ARXPS) analysis of [EMIM][EtPO3H] did not show any change in the composition of the surface before and after chronoamperometry, since the sampling depth (1.5 nm at the highest emission angle) is larger than the cation and anion sizes (ca. 7 and 5 Å, respectively). Characterization of the coating was made by scanning electron microscopy (SEM), focussed ion beam SEM, energy dispersive X-ray spectroscopy, XPS, and ARXPS. FIB-SEM shows that the coating presents a mean thickness of 374 (±36) nm and contains magnesium and aluminum phosphates. Linear reciprocating tribological tests under variable load show that the presence of the coating can reduce friction coefficients of the coated AZ31B against steel up to 32% and wear rates up to 90%, with respect to the uncoated alloy.

  2. Liquid Phase Sintering of Carbides Using a Nickel-Molybdenum Alloy

    Science.gov (United States)

    1988-07-01

    AD TECHNICAL REPORT ARCCB-TR-88031 LIQUID PHASE SINTERING OF CARBIDES USING A NICKEL-MOL YBDENUM ALL 0 Y co J. M. BARRANCO mS R. A. WARENCHAK...ORG. REPORT NUMBER 7. AUTHOR(e) S. CONTRACT OR GRANT NUMBER,) J. M. Barranco and R. A. Warenchak 9. PERFORMING ORGANIZATION NAME AND ADDRESS 10

  3. XPS Depth Study on the Liquid Oxidation of Sn-Bi-Zn-X(Al/P Alloy and the Effect of Al/P on the Film

    Directory of Open Access Journals (Sweden)

    X. J. Wang

    2015-01-01

    Full Text Available X-ray photoelectron spectroscopy (XPS was used to study the properties of liquid oxidation of Sn-Bi-Zn (SBZ solder alloys and the effect of Al/P on the oxide film. The results showed that the oxidation film on SBZ surface was in high concentration of both oxygen and zinc. Adding trace amount of Al/P to SBZ alloys (SBZA/ABZP decreased the ratio of O/M (M could be Sn, Bi, and Al/P and changed the film compositions. Layers near the free surface of oxidation film mostly contained Zn2+ and Al3+ oxides for SBZA. From the half quantitative analysis result, the aluminum had a surface enrichment behavior in liquid solder, so did phosphorus and zinc. Therefore, the Al/P addition changed their stoichiometry such as the ratio of O/M near film surface.

  4. PLUTONIUM-THORIUM ALLOYS

    Science.gov (United States)

    Schonfeld, F.W.

    1959-09-15

    New plutonium-base binary alloys useful as liquid reactor fuel are described. The alloys consist of 50 to 98 at.% thorium with the remainder plutonium. The stated advantages of these alloys over unalloyed plutonium for reactor fuel use are easy fabrication, phase stability, and the accompanying advantuge of providing a means for converting Th/sup 232/ into U/sup 233/.

  5. Modeling of Coalescence and Separation of Liquid Droplets During Solidification of Immiscible Alloys

    Institute of Scientific and Technical Information of China (English)

    Lirong; Tong; Nagy; El-Kaddah

    2002-01-01

    Directional solidification methods are being used f or in-situ production of metallic immiscible composites. A quantitative understa nding of the dynamic behavior and growth kinetics of the nucleated second phase during solidification is necessary to produce homogeneous dispersion in solidifi ed composites. This paper presents a mathematical model for describing the grow th of nucleated dispersed phase in the two-liquid phase region ahead of the sol idification front and the entrapment of these droplets...

  6. Structure of the glass-forming metallic liquids by ab-initio and classical molecular dynamics, a case study: Quenching the Cu60Ti20Zr20 alloy

    Science.gov (United States)

    Amokrane, S.; Ayadim, A.; Levrel, L.

    2015-11-01

    We consider the question of the amorphization of metallic alloys by melt quenching, as predicted by molecular dynamics simulations with semi-empirical potentials. The parametrization of the potentials is discussed on the example of the ternary Cu-Ti-Zr transition metals alloy, using the ab-initio simulation as a reference. The pair structure in the amorphous state is computed from a potential of the Stillinger-Weber form. The transferability of the parameters during the quench is investigated using two parametrizations: from solid state data, as usual and from a new parametrization on the liquid structure. When the adjustment is made on the pair structure of the liquid, a satisfactory transferability is found between the pure components and their alloys. The liquid structure predicted in this way agrees well with experiment, in contrast with the one obtained using the adjustment on the solid. The final structure, after quenches down to the amorphous state, determined with the new set of parameters is shown to be very close to the ab-initio one, the latter being in excellent agreement with recent X-rays diffraction experiments. The corresponding critical temperature of the glass transition is estimated from the behavior of the heat capacity. Discussion on the consistency between the structures predicted using semi-empirical potentials and ab-initio simulation, and comparison of different experimental data underlines the question of the dependence of the final structure on the thermodynamic path followed to reach the amorphous state.

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

    Directory of Open Access Journals (Sweden)

    A.N. AlHazaa

    2016-04-01

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

  8. Accuracy of Ceramic Mould Filling with Liquid AlSi9 Aluminium Alloy in the Process Using Back-pressure

    Directory of Open Access Journals (Sweden)

    A. Karwiński

    2013-01-01

    Full Text Available The paper presents the effect of suction pressure exerted on the liquid AlSi alloy when it is introduced into a ceramic mould made in the investment process and the results compared with data obtained on gravity poured castings.The study used special pattern sets and ceramic moulds made with the alternately applied soluble silicate binder and ethyl silicate.Additionally, self-supported moulds based entirely on the Ekosil binder were used. In the analysis of castings, the following parameters were examined: a linear dimensional accuracy, the state of surface microgeometry and the possibility of metal penetration into a complex ceramic mould, allowing also for the presence of capillary phenomena. In the process of casting with back-pressure, the pressure values of 500 hPa, 600 hPa and 700 hPa were applied in the chamber where the ceramic mould was located, with the temperature of the said mould kept at a level of 150  10C.

  9. Modelling of nodular particle growth in a liquid-solid film during condensation experiments of copper-silver alloys

    Energy Technology Data Exchange (ETDEWEB)

    Leroux, S.; Ny, J. le; Gueneau, C.; Goldstein, S. [DCC/DPE/SPCP/LEPCA, Commissariat a l' Energie Atomique Saclay, Gif-sur-Yvette (France); Camel, D. [DTA/CEREM/DEM/SPCM, Commissariat a l' Energie Atomique, Centre d' Etudes Nucleaires de Grenoble, Grenoble (France)

    2001-07-01

    Silver-copper alloys are condensed in a liquid-solid domain of the phase diagram on a tilted molybdenum substrate regulated in temperature. After a droplets regime, a film which contains a monolayer of nodular solid crystals forms. The size distribution and density of the particles in the film are measured after different condensation times. Results show that in our experimental conditions a ripening process occurs which is evidenced by a decrease of the number of particles with time, and a broad particle size distribution. However, the decrease rate is smaller than expected without a condensation flux. A model is then developed to interpret and generalize these results. This model results from the modification of the Lifshitz-Slyosov model to take into account the supply from the vapour phase. It is shown that the higher the flux of material to solidify from the vapour phase is, the more the growth from the vapour phase overcomes the ripening process. Once the particle density reaches a characteristic value which is simply proportional to the incoming flux, no more particles are dissolved. The system then tends towards a monomodal distribution with a radius which grows in t{sup 1/3}. (orig.)

  10. Solid-Liquid State Bonding of Si3N4 Ceramics with Ceramic-Modified Brazing Alloy

    Institute of Scientific and Technical Information of China (English)

    杨俊; 吴爱萍; 邹贵生; 张德库; 刘根茂

    2004-01-01

    Solid-liquid state bonding of Si3N4 ceramics with TiN-modified Ag-Cu-Ti brazing alloy was used to enhance joint strength. The effects of the TiN particles on the microstructures, interfacial reactions, and room-temperature properties of the joints were investigated. The results show that the TiN particles are generally well dispersed in the Ag-Cu eutectic base and the interface between them is both clean and compact. Changes in the TiN volume fractions from 0 to 20% exert no noticeable effect on the interfacial reaction between Ag-Cu-Ti and the substrates. Other bonding parameters being constant, the TiN volume fraction in the filler material plays a key role in the joint properties. For TiN volume fractions below 20%, the joints are reinforced, especially joints with 5% and 20% TiN. The average shearing strength of joints with 5%TiN is 200.8 MPa, 30% higher than that of joints with no TiN (154.1 MPa). However, for TiN volumes fractions above 20%, the joint strengths decrease.

  11. Influence of water on the interfacial behavior of gallium liquid metal alloys.

    Science.gov (United States)

    Khan, Mohammad R; Trlica, Chris; So, Ju-Hee; Valeri, Michael; Dickey, Michael D

    2014-12-24

    Eutectic gallium indium (EGaIn) is a promising liquid metal for a variety of electrical and optical applications that take advantage of its soft and fluid properties. The presence of a rapidly forming oxide skin on the surface of the metal causes it to stick to many surfaces, which limits the ability to easily reconfigure its shape on demand. This paper shows that water can provide an interfacial slip layer between EGaIn and other surfaces, which allows the metal to flow smoothly through capillaries and across surfaces without sticking. Rheological and surface characterization shows that the presence of water also changes the chemical composition of the oxide skin and weakens its mechanical strength, although not enough to allow the metal to flow freely in microchannels without the slip layer. The slip layer provides new opportunities to control and actuate liquid metal plugs in microchannels-including the use of continuous electrowetting-enabling new possibilities for shape reconfigurable electronics, sensors, actuators, and antennas.

  12. Formation of coatings from a liquid phase on the surface of iron-base alloys

    Directory of Open Access Journals (Sweden)

    A. Tatarek

    2008-12-01

    Full Text Available The study discloses the present state of the art regarding the technology and investigations of the phenomena that take place during the formation and growth of aluminum and zinc coatings hot-dip formed on iron products. In its cognitive aspect, the study offers an in-depth analysis of the partial processes that proceed in metal bath at the solid body – liquid metal interface. It is expected that the present study will help in a more detailed description of the respective phenomena and in full explanation of the mechanism of the coating growth, taking as an example the growth of aluminum coatings. The obtained results can serve as a background for some general conclusions regarding the thickness evolution process in other hot-dip coatings.

  13. Interfacial Microstructure of Al-Sn-Pb Alloy/Steel During Liquid-Solid Bonding Rolling

    Institute of Scientific and Technical Information of China (English)

    XU Guang-ming; LI Bao-mian; CUI Jian-zhong

    2006-01-01

    Studies were conducted on the interfacial microstructure of a steel/liquid aluminium and its evolution during the bonding rolling process. The effects of wetting time and deformation on the diffusion layer and on the bonding strength were examined. By means of electron microscopy and electron probe analysis, it was found that the diffusion layer is mainly composed of FeAl3. For a steel temperature of 250 ℃ and an aluminium temperature of 850 ℃, the diffusion layer was formed within 3 s, and the shear strength of the samples increased after 8 to 14 s. Although the interface was not damaged, it was deformed notably. For an aluminium temperature of 750 ℃ and a wetting time of 11 to 17 s, the shear strength of the interface remained high, but the interface was obviously broken during rolling, leading to reduced bonding strength.

  14. Evolution of solid-liquid interface morphology of primary TiB2 in non-equilibrium solidified Ti-Al-B alloys

    Institute of Scientific and Technical Information of China (English)

    张虎; 高文理; 金云学; 曾松岩

    2002-01-01

    Ti-Al-B alloys were produced by in-situ synthesis method. The phase constitutions, microstructure of these alloys and the morphology of the primary TiB2 were investigated by XRD and SEM. The results show that these alloys are composed of TiAl and TiB2, and the primary TiB2 is hexagonal prism shape. Growth terraces, pyramidal protrusion, and rod shape dendrites are observed on (0001) plane of primary TiB2. There are thin flake convexes on plane of primary TiB2, parallel to (0001) plane of the primary TiB2. The rod-shaped crystal orientation and thin flake convexes are parallel to primary TiB2 where they protrude out. The solid-liquid interface morphology of primary TiB2 during solidification was also investigated. It was indicated that the solid-liquid interface morphology of primary TiB2 is instable and gradually develops into a complicated interface consisted of a few separated secondary interfaces. These secondary interfaces are facet with the same crystalline orientation.

  15. Thermodynamic modelling of Li–Sn liquid alloy based on Knudsen effusion mass spectrometric measurements

    Energy Technology Data Exchange (ETDEWEB)

    Bencze, L., E-mail: bencze@chem.elte.hu [Institute for Energy and Climate Research (IEK-2), Forschungszentrum Jülich GmbH, D-52425 Jülich (Germany); Eötvös Loránd University, Dept. of Physical Chemistry, H-1117 Budapest, Pázmány Péter sétány 1/A (Hungary); Henriques, D. [Institute for Energy and Climate Research (IEK-2), Forschungszentrum Jülich GmbH, D-52425 Jülich (Germany); Motalov, V. [Institute for Energy and Climate Research (IEK-2), Forschungszentrum Jülich GmbH, D-52425 Jülich (Germany); Department of Physics, Ivanovo State University of Chemistry and Technology, Sheremetevsky av.7, 153000 Ivanovo (Russian Federation); Markus, T. [Institute for Energy and Climate Research (IEK-2), Forschungszentrum Jülich GmbH, D-52425 Jülich (Germany)

    2014-09-01

    Highlights: • The experimental KEMS data fit well with the Redlich–Kister sub-regular solution model applied to Li–Sn melt. • The Redlich–Kister binary interaction L-parameters of the Li–Sn melt were provided in this work. • The experimental KEMS data fit well with the ideally associated mixture model, too. • The quantitative associate composition of the Li–Sn melt was given. • The thermodynamic properties of the associate-forming reactions were also provided. - Abstract: The mixing thermodynamic properties of liquid Li–Sn system, determined previously by Knudsen effusion mass spectrometry (KEMS), were successfully fitted to both Redlich–Kister (RK) sub-regular mixture and ideally associated mixture (IAMT) models. The RK binary interaction L parameters, as a function of temperature in the CALPHAD-type functional form, were obtained as follows: L{sup (0)}=-(108580±0.00171)+(16.4±1.6·10{sup -5})·T+(1.96496·10{sup -9}±2.03133·10{sup -6}) ·T·ln(T) L{sup (1)}=-(96600±4700)+(3.3±43.0)·T+(4.4±5.6)·T·ln(T) L{sup (2)}=-(64670±190)-(44.4±1.7)·T+(8.44±0.22)·T·ln(T) L{sup (3)}=-(20900±1500)-(29±14)·T+(4.3±1.8)·T·ln(T) The former literature data provided only qualitative information on possible liquid associates but no quantitative associate composition was given as a function of the sample composition and temperature. The experimental KEMS data in the composition range X{sub Li} = 0 to ∼0.7 fit well with the Li(l) + Sn(l) + LiSn(l) + LiSn{sub 2}(l) + Li{sub 2}Sn(l) associate model. At X{sub Li} > 0.7 no associate variations – including further associate variants such as Li{sub 4}Sn(l) etc. – could be fitted to the KEMS data. Nevertheless, in this work the Li(l) + Sn(l) + LiSn(l) + LiSn{sub 2}(l) + Li{sub 2}Sn(l) + Li{sub 4}Sn(l) + Li{sub 9}Sn(l) associate model was successfully fitted to the thermodynamic data of a selected literature study over the complete composition range. The thermodynamic data of the associate

  16. Electrical resistivity and thermal conductivity of liquid Fe alloys at high P and T, and heat flux in Earth’s core

    Science.gov (United States)

    de Koker, Nico; Steinle-Neumann, Gerd; Vlček, Vojtěch

    2012-01-01

    Earth’s magnetic field is sustained by magnetohydrodynamic convection within the metallic liquid core. In a thermally advecting core, the fraction of heat available to drive the geodynamo is reduced by heat conducted along the core geotherm, which depends sensitively on the thermal conductivity of liquid iron and its alloys with candidate light elements. The thermal conductivity for Earth’s core is very poorly constrained, with current estimates based on a set of scaling relations that were not previously tested at high pressures. We perform first-principles electronic structure computations to determine the thermal conductivity and electrical resistivity for Fe, Fe–Si, and Fe–O liquid alloys. Computed resistivity agrees very well with existing shock compression measurements and shows strong dependence on light element concentration and type. Thermal conductivity at pressure and temperature conditions characteristic of Earth’s core is higher than previous extrapolations. Conductive heat flux near the core–mantle boundary is comparable to estimates of the total heat flux from the core but decreases with depth, so that thermally driven flow would be constrained to greater depths in the absence of an inner core. PMID:22375035

  17. Fluidic patch antenna based on liquid metal alloy/single-wall carbon-nanotubes operating at the S-band frequency

    Science.gov (United States)

    Aïssa, B.; Nedil, M.; Habib, M. A.; Haddad, E.; Jamroz, W.; Therriault, D.; Coulibaly, Y.; Rosei, F.

    2013-08-01

    This letter describes the fabrication and characterization of a fluidic patch antenna operating at the S-band frequency (4 GHz). The antenna prototype is composed of a nanocomposite material made by a liquid metal alloy (eutectic gallium indium) blended with single-wall carbon-nanotube (SWNTs). The nanocomposite is then enclosed in a polymeric substrate by employing the UV-assisted direct-writing technology. The fluidic antennas specimens feature excellent performances, in perfect agreement with simulations, showing an increase in the electrical conductivity and reflection coefficient with respect to the SWNTs concentration. The effect of the SWNTs on the long-term stability of antenna's mechanical properties is also demonstrated.

  18. Dendrite growth kinetics of βZr phase within highly undercooled liquid Zr-Si hypoeutectic alloys under electrostatic levitation condition

    Science.gov (United States)

    Hu, L.; Yang, S. J.; Wang, L.; Zhai, W.; Wei, B.

    2017-04-01

    The liquid Zr100-xSix (x = 1, 3, and 5) alloys were substantially undercooled by up to 392 K (0.19TL), 423 K (0.21TL), and 451 K (0.23TL), respectively, under the electrostatic levitation condition. The measured dendrite growth velocity of the primary βZr phase increased with the enhancement of liquid undercooling. Although the undercooling ability showed an increasing tendency with the increase in the Si content, dendrite growth was obviously depressed due to the dominance of solute diffusion controlled growth. Their critical undercoolings for kinetics transition from solute diffusion to thermal diffusion controlled growth were determined. It demonstrates a remarkable refinement of dendrites and an increasing trend of Si solubility in αZr dendrites with increasing undercooling.

  19. THE INFLUENCE OF HEAT TREATMENT WITH THE LIQUID PHASE ON FORMATION OF A MICROSTRUCTURE OF EUTECTIC Al-Si-ALLOY

    Directory of Open Access Journals (Sweden)

    A. Anikin

    2015-01-01

    Full Text Available The effect of heat treatment on the structure of the eutectic Al-Si-alloy, a theoretical substantiation process based on thermal analyzer and cooked microstructures was presented in this paper.

  20. Numerical Modeling and In-Situ Observations of the Dynamics of the Solid/Liquid Interface Morphology During Directional Solidification of Alloys

    Science.gov (United States)

    Catalina, Adrian V.; Stefanescu, Doru M.; Sen, Subhayu; Curreri, Peter A.; Kaukler, W. F.

    1999-01-01

    The departure from interface planarity and the subsequent evolution to a periodic array of cells or dendrites is a fundamental process that characterizes most microstructures in solidified alloys. The growing demand for high quality alloys and semiconductor crystals requires a precise methodology to predict and subsequently control both the interface morphology and the distribution of impurities, additives, and phases in the grown crystal. Apart from its practical significance, the study of morphological evolution has also been viewed as a means to unearth a general paradigm for pattern formation in nature. A previously developed 2D numerical model for the solid/liquid interface tracking has been further refined and used to simulate the time-evolution of the perturbations on the interface. The dynamics of the local growth velocity, interface undercooling and solute concentration at the interface has been theoretically predicted by means of the numerical model for Al-Cu and Pb-Sn alloys. The model shows that perturbations with a wavelengths, lambda greater than a critical wavelength lambda(sub c) continue to grow in time whereas perturbations with lambda interface. Comparison of these predictions with existing theories of pattern formation and experimental results will be discussed.

  1. Numerical Modeling and In-Situ Observations of the Dynamics of the Solid/Liquid Interface Morphology During Directional Solidification of Alloys

    Science.gov (United States)

    Catalina, Adrian V.; Stefanescu, Doru M.; Sen, Subhayu; Curreri, Peter A.; Kaukler, W. F.

    1999-01-01

    The departure from interface planarity and the subsequent evolution to a periodic array of cells or dendrites is a fundamental process that characterizes most microstructures in solidified alloys. The growing demand for high quality alloys and semiconductor crystals requires a precise methodology to predict and subsequently control both the interface morphology and the distribution of impurities, additives, and phases in the grown crystal. Apart from its practical significance, the study of morphological evolution has also been viewed as a means to unearth a general paradigm for pattern formation in nature. A previously developed 2D numerical model for the solid/liquid interface tracking has been further refined and used to simulate the time-evolution of the perturbations on the interface. The dynamics of the local growth velocity, interface undercooling and solute concentration at the interface has been theoretically predicted by means of the numerical model for Al-Cu and Pb-Sn alloys. The model shows that perturbations with a wavelengths, lambda greater than a critical wavelength lambda(sub c) continue to grow in time whereas perturbations with lambda < lambda(sub c) cease to propagate. The model further predicts that under certain conditions perturbation can also propagate along the interface. Comparison of these predictions with existing theories of pattern formation and experimental results will be discussed.

  2. Diffusion of liquid uranium into foils of tantalum metal and tantalum-10 wt% tungsten alloy up to 1350/sup 0/C

    Energy Technology Data Exchange (ETDEWEB)

    Kuznietz, M.; Livne, Z.; Cotler, C.; Erez, G.

    1988-05-01

    Immersion experiments have been performed to investigate the diffusion of liquid uranium into 0.3 mm thick foils of tantalum metal and tantalum-10wt% tungsten alloy in the temperature range of 1160/sup 0/C to 1350/sup 0/C, for reaction times up to 20 h, in zirconia crucibles. The orginal and uranium-reacted foils have been studied microscopically (SEM-EDAX) and a multilayer structure is revealed in the reacted foils. Layers identified for tantalum immersed in uranium: Uranium-tantalum (U/Ta approx. = 1), precipitated columnar tantalum (< 1wt% U), inner uranium, and inner tantalum (with grown grains and uranium along grain boundaries). Layers identified for Ta-10wt% W alloy immersed in uranium: Uranium-tantalum (U/Ta approx. = 1, 0.3wt% W), precipitated tantalum (< 1wt% U, down to 1-2wt% W), and inner Escher-type grains of tantalum-tungsten (up to 18wt% W) and of uranium (< 2wt% Ta, < 0.4wt% W). A mechanism for the multilayer formation and the intrusion of liquid uranium into the solid foils is proposed and substantiated.

  3. SERS-active Ag, Au and Ag–Au alloy nanoparticles obtained by laser ablation in liquids for sensing methylene blue

    Energy Technology Data Exchange (ETDEWEB)

    Olea-Mejía, Oscar, E-mail: oleaoscar@yahoo.com.mx [Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Universidad Autónoma del Estado de México, km 14.5 Carretera Toluca-Atlacomulco, San Cayetano 50200, México (Mexico); Fernández-Mondragón, Mariana; Rodríguez-de la Concha, Gabriela [Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Universidad Autónoma del Estado de México, km 14.5 Carretera Toluca-Atlacomulco, San Cayetano 50200, México (Mexico); Camacho-López, Marco [Laboratorio de Investigación y Desarrollo de Materiales Avanzados, Universidad Autónoma del Estado de México, Km 14.5 Carretera Toluca-Atlacomulco, San Cayetano 50925, México (Mexico)

    2015-09-01

    Highlights: • We synthesized Ag/Au nanoparticles by laser ablation in liquids. • We characterized such particles by UV–vis, TEM and EDS/STEM. • The SERS effect was studied for the obtained nanoparticles. • Pure silver nanoparticles showed the highest SERS signals. • We can sense methylene blue at a concentration of 10{sup −10} mole/L. - Abstract: We have synthesized Ag–Au nanoparticles by laser ablation in liquids using five different targets: 100% Ag, 80%Ag/20%Au, 50%Ag/50%Au, 20%Ag/80%Au and 100% Au (weight percentages). We used ethanol and methylene blue solutions in ethanol as the liquid media. The nanoparticles were mostly spherical with diameters 15, 19, 18, 23 and 11 nm, respectively. When alloyed targets were used, the resulting nanoparticles were completely alloyed forming solid solutions as evidenced by UV–vis Spectroscopy and Scanning Transmission Electron Microscopy. The obtained nanoparticles were employed to study the SERS effect of the methylene blue molecule. All the samples showed good SERS activity, however the ones composed of pure silver showed the greatest Raman signal enhancement. Finally, pure Ag nanoparticles were used for sensing methylene blue at different concentrations. While almost no signal can be discerned from the Raman spectrum when no particles are used at a concentration of methylene blue of 1 × 10{sup −2} M (∼3000 ppm), when Ag nanoparticles are used one can observe the characteristic peak of the molecule at concentrations as low as 1 × 10{sup −10} M (∼3 × 10{sup −5} ppm)

  4. Tuning the structural and optical properties of gold/silver nano-alloys prepared by laser ablation in liquids for optical limiting, ultra-sensitive spectroscopy, and optical trapping

    Science.gov (United States)

    Messina, E.; D'Urso, L.; Fazio, E.; Satriano, C.; Donato, M. G.; D'Andrea, C.; Maragò, O. M.; Gucciardi, P. G.; Compagnini, G.; Neri, F.

    2012-12-01

    The plasmon resonance of metallic Au/Ag nano-alloys in the colloidal state was tuned from 400 nm to 500 nm using a laser irradiated technique performed directly in the liquid state. Interesting optical nonlinearities, trapping effects and spectroscopic enhancements were detected by modifying the gold molar fraction in the nano-alloys. In particular a reduction of the limiting threshold was observed by increasing the gold amount. The SERS activity of the Au/Ag alloys was tested in liquid and in solid state in presence of linear carbon chains as probe molecules. The increased Raman signals for nanoparticles with different Au/Ag atomic ratio are presented. Finally, studies and prospects for optical and Raman tweezers experiments are discussed.

  5. Characterization of surface liquid segregation in SSM-HPDC aluminium alloys 7075, 2024, 6082 and A201

    CSIR Research Space (South Africa)

    Moller, H

    2010-09-01

    Full Text Available analysis. Chemical profiles of the main alloying elements were plotted for the cross-section of the plates in the as-cast and T6 (after solution treatment) temper conditions. Vickers hardness profiles from the surface to the centre of the plates were...

  6. Influence of surface liquid segregation on corrosion behavior of semi-solid metal high pressure die cast aluminium alloys

    CSIR Research Space (South Africa)

    Masuku, EP

    2010-09-01

    Full Text Available alloys 7075-T6 and 2024-T6. Potentiodynamic testing was performed in deaerated 3.5%NaCl solution. In separate tests, the open-circuit potential was monitored in aerated 3.5% NaCl for 30 minutes after immersion. The electrochemical tests show...

  7. Ultrasonic cavitation erosion of 316L steel weld joint in liquid Pb-Bi eutectic alloy at 550°C.

    Science.gov (United States)

    Lei, Yucheng; Chang, Hongxia; Guo, Xiaokai; Li, Tianqing; Xiao, Longren

    2017-11-01

    Liquid lead-bismuth eutectic alloy (LBE) is applied in the Accelerator Driven transmutation System (ADS) as the high-power spallation neutron targets and coolant. A 19.2kHz ultrasonic device was deployed in liquid LBE at 550°C to induce short and long period cavitation erosion damage on the surface of weld joint, SEM and Atomic force microscopy (AFM) were used to map out the surface properties, and Energy Dispersive Spectrometer (EDS) was applied to the qualitative and quantitative analysis of elements in the micro region of the surface. The erosion mechanism for how the cavitation erosion evolved by studying the element changes, their morphology evolution, the surface hardness and the roughness evolution, was proposed. The results showed that the pits, caters and cracks appeared gradually on the erode surface after a period of cavitation. The surface roughness increased along with exposure time. Work hardening by the bubbles impact in the incubation stage strengthened the cavitation resistance efficiently. The dissolution and oxidation corrosion and cavitation erosion that simultaneously happened in liquid LBE accelerated corrosion-erosion process, and these two processes combined to cause more serious damage on the material surface. Contrast to the performance of weld metal, base metal exhibited a much better cavitation resistance. Copyright © 2017. Published by Elsevier B.V.

  8. Investigations on the Influence of Liquid-Assisted Laser Ablation of NiTi Rotating Target to Improve the Formation Efficiency of Spherical Alloyed NiTi Nanoparticles

    Science.gov (United States)

    Nandini, Patra; Akash, K.; Rohit, Gagrani; Vipul, Singh; Palani, I. A.

    2017-09-01

    In this work, the liquid-assisted laser ablation of NiTi rotating target has been used as a promising technique for generating spherical NiTi alloy nanoparticles with higher formation efficiency. Nd: YAG nanosecond laser with three different laser wavelengths (355, 532 and 1064 nm), three different laser fluences (30, 40 and 50 J/cm2) and three different rotational speeds (10 RPM, 20 RPM and 30 RPM) of target has been used to ablate the nitinol (Ni-55%, Ti-45%) target. The influences of different laser parameters (wavelengths and fluences) and different RPMs have been studied on the size, morphology and formation of alloy nanoparticles. It has been observed that the formation efficiency is maximum (39.9 mg/h) for smaller size nanoparticle ( 40 nm) at 355 nm wavelength, 50 J/cm2 fluence and 10 RPM rotational speed. On the other hand, we find that the formation efficiency (10.5 mg/h) is lowest with a bigger size of nanoparticle ( 110 nm) at 1064 nm wavelength, 50 J/cm2 fluence and 30 RPM speed. Therefore, this is a promising technique to synthesize spherical alloy nanoparticles with higher ablation efficiency. Thus, the higher ablation of particles helps to improve the optical absorption of the colloidal solution as optical absorption has a direct relation with the particle concentration. The shape and size of particles were characterized through SEM and DLS analysis whereas the crystallinity was confirmed through TEM and XRD analysis, respectively. Moreover, the elemental analysis was done with the help of XPS and EDS and optical absorption through UV-Vis spectrum analysis.

  9. Transient Liquid Phase Bonding of Cu-Cr-Zr-Ti Alloy Using Ni and Mn Coatings: Microstructural Evolution and Mechanical Properties

    Science.gov (United States)

    Venkateswaran, T.; Ravi, K. R.; Sivakumar, D.; Pant, Bhanu; Janaki Ram, G. D.

    2017-08-01

    High-strength copper alloys are used extensively in the regenerative cooling parts of aerospace structures. Transient liquid phase (TLP) bonding of a Cu-Cr-Zr-Ti alloy was attempted in the present study using thin layers of elemental Ni and Mn coatings applied by electroplating. One of the base metals was given a Ni coating of 4 µm followed by a Mn coating of 15 µm, while the other base metal was given only the Ni coating (4 µm). The bonding cycle consisted of the following: TLP stage—heating to 1030 °C and holding for 15 min; homogenization stage—furnace cooling to 880 °C and holding for 2 h followed by argon quenching to room temperature. Detailed microscopy and electron probe microanalysis analysis of the brazed joints were carried out. The braze metal was found to undergo isothermal solidification within the 15 min of holding time at 1030 °C. At the end of TLP stage, the braze metal showed a composition of Cu-17Ni-9Mn (wt.%) at the center of the joint with a steep gradient in Ni and Mn concentrations from the center of the braze metal to the base metal interfaces. After holding for 2 h at 880 °C (homogenization stage), the compositional gradients were found to flatten significantly and the braze metal was found to develop a homogeneous composition of Cu-11Ni-7Mn (wt.%) at the center of the joint. In lap-shear tests, failures were always found to occur in the base metal away from the brazed region. The copper alloy base metal was found to undergo significant grain coarsening due to high-temperature exposure during brazing and, consequently, suffer considerable reduction in yield strength.

  10. Correlation between dynamic slowing down and local icosahedral ordering in undercooled liquid Al{sub 80}Ni{sub 20} alloy

    Energy Technology Data Exchange (ETDEWEB)

    Jakse, N.; Pasturel, A. [Sciences et Ingénierie des Matériaux et Procédés, UMR CNRS 5266, Grenoble Université Alpes, BP 75, 38402 Saint-Martin d’Hères Cedex (France)

    2015-08-28

    We use ab initio molecular dynamics simulations to study the correlation between the local ordering and the dynamic properties of liquid Al{sub 80}Ni{sub 20} alloy upon cooling. Our results evidence a huge increase of local icosahedral ordering (ISRO) in the undercooled regime which is more developed around Ni than Al atoms. We show that ISRO has a strong impact on self-diffusion coefficients of both species and is at the origin of their crossover from Arrhenius to non-Arrhenius behavior around a crossover temperature T{sub X} = 1000 K, located in the undercooled region. We also clearly identify that this temperature corresponds to the development of dynamic heterogeneities and to the breakdown of the Stokes-Einstein relation. At temperatures below this crossover, we find that the behavior of the diffusion and relaxation dynamics is mostly incompatible with predictions of the mode-coupling theory. Finally, an analysis of the van Hove function indicates that the crossover temperature T{sub X} marks the onset of a change in the diffusion mechanism from a normal flow to an activated process with hopping. From these results, the glass-forming ability of the alloy is discussed.

  11. Electric and magnetic properties of Al{sub 86}Ni{sub 8}R{sub 6} (R=Sm, Gd, Ho) alloys in liquid and amorphous states

    Energy Technology Data Exchange (ETDEWEB)

    Sidorov, V. [Ural State Pedagogical University, Ekaterinburg (Russian Federation); Ural Federal University, Ekaterinburg (Russian Federation); Svec, P.; Svec, P.; Janickovic, D. [Institute of Physics SAS, Bratislava (Slovakia); Mikhailov, V. [Ural State Pedagogical University, Ekaterinburg (Russian Federation); Sidorova, E. [Plekhanov Russian University of Economics, Moscow (Russian Federation); Son, L. [Ural State Pedagogical University, Ekaterinburg (Russian Federation); Ural Federal University, Ekaterinburg (Russian Federation)

    2016-06-15

    Electrical resistivity and magnetic susceptibility of Al{sub 86}Ni{sub 8}Sm{sub 6}, Al{sub 86}Ni{sub 8}Gd{sub 6} and Al{sub 86}Ni{sub 8}Ho{sub 6} alloys are studied in a wide temperature range including amorphous, crystalline and liquid states. The negative value of resistivity temperature coefficient in amorphous ribbons is explained by the structural separation starting much before the beginning of their crystallization. The effective magnetic moments per Gd and Ho atoms are found to be essentially lower than for R{sup 3+} ions. The results are discussed in supposition of directed bonds between rare earth and aluminum atoms. - Highlights: • Electric and magnetic properties of Al{sub 86}Ni{sub 8}R{sub 6} alloys are studied experimentally. • The negative value of rtc in amorphous ribbons is explained. • The effective magnetic moments per Gd and Ho are found to be lower than for R{sup 3+} ions.

  12. Comparison of the Molecular Interaction Volume Model with the Unified Interaction Parameter Formalism in the Fe-Cr-Ni Liquid Alloys at 1873 K

    Institute of Scientific and Technical Information of China (English)

    Dongping TAO

    2006-01-01

    The molecular interaction volume model (MIVM) for a general ternary system was deduced in detail for further clarifying and understanding its general multicomponent expression. Both MIVM and the unified interaction parameterformalism (UIPF) can be used to predict the activities of solutes and solvents in the Fe-Cr-Ni liquid alloys. But the former employs only the infinite dilute activity coefficients, and the later is not applicable without the dilute binary and ternary interaction parameters. MIVM has a certain physical meaning from the viewpoint of statistical thermodynamics, so it is an alternative for the estimation of activity coefficients of the solutes and solvents in a dilute or finite concentration metal solution where the interaction parameters are absent or their accuracies are questionable.

  13. Non-linear effects of initial melt temperatures on microstructures and mechanical properties during quenching process of liquid Cu46Zr54 alloy

    Science.gov (United States)

    Mo, Yun-Fei; Liu, Rang-Su; Tian, Ze-An; Liang, Yong-Chao; Zhang, Hai-Tao; Hou, Zhao-Yang; Liu, Hai-Rong; Zhang, Ai-long; Zhou, Li-Li; Peng, Ping; Xie, Zhong

    2015-05-01

    A MD simulation of liquid Cu46Zr54 alloys has been performed for understanding the effects of initial melt temperatures on the microstructural evolution and mechanical properties during quenching process. By using several microstructural analyzing methods, it is found that the icosahedral and defective icosahedral clusters play a key role in the microstructure transition. All the final solidification structures obtained at different initial melt temperatures are of amorphous structures, and their structural and mechanical properties are non-linearly related to the initial melt temperatures, and fluctuated in a certain range. Especially, there exists a best initial melt temperature, from which the glass configuration possesses the highest packing density, the optimal elastic constants, and the smaller extent of structural softening under deforming.

  14. Microstructure Evolution of Ti-47Al-2Cr-2Nb Alloy in the Liquid-Metal-Cooling (LMC) Directional-Solidification Process

    Institute of Scientific and Technical Information of China (English)

    XIAO Zhixia; ZHENG Lijing; WANG Lei; YANG Lili; ZHANG Hu

    2011-01-01

    The microstructure evolution of Ti-47Al-2Cr-2Nb alloy was investigated on liquid metal cooling type directional solidified apparatus at high temperature gradient. The analysis shows that it is solidified with primaryβ cells/dendrites, and then α phase is formed through peritectic reaction.Once the columnar grains grow into the steady state, the lameilar orientation inclined with the angle of 45° to the withdrawal direction is more favored than that with parallel to the withdrawal direction. In addition, α phase grain nucleates from β-interdendrite regions, and grows up to the dendritic trunk. If no other α grain hinders its growth, it would occupy the whole dendrite, or it would stop at the dendritic trunk for the weakened motivating drive in theβ dendritic core.

  15. Comparison of lithium and the eutectic lead lithium alloy, two candidate liquid metal breeder materials for self-cooled blankets

    Energy Technology Data Exchange (ETDEWEB)

    Malang, S. [Kernforschungszentrum Karlsruhe GmbH (Germany); Mattas, R. [Argonne National Lab., IL (United States)

    1994-06-01

    Liquid metals are attractive candidates for both near-term and long-term fusion applications. The subjects of this comparison are the differences between the two candidate liquid metal breeder materials Li and LiPb for use in breeding blankets in the areas of neutronics, magnetohydrodynamics, tritium control, compatibility with structural materials, heat extraction system, safety, and required R&D program. Both candidates appear to be promising for use in self-cooled breeding blankets which have inherent simplicity with the liquid metal serving as both breeders and coolant. The remaining feasibility question for both breeder materials is the electrical insulation between liquid metal and duct walls. Different ceramic coatings are required for the two breeders, and their crucial issues, namely self-healing of insulator cracks and radiation induced electrical degradation are not yet demonstrated. Each liquid metal breeder has advantages and concerns associated with it, and further development is needed to resolve these concerns.

  16. Solid/liquid interaction between a multicomponent FeCrNiCoMnAl high entropy alloy and molten aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Hung-Hua [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 701, Taiwan (China); Tsai, Wen-Ta, E-mail: wttsai@mail.ncku.edu.tw [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 701, Taiwan (China); Kuo, Jui-Chao [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 701, Taiwan (China); Yang, Chih-Chao [Industrial Technology Research Institute, 31 Gongye 2nd Rd., Annan District, Tainan 709, Taiwan (China)

    2011-08-11

    Highlights: > The interfacial reaction between a high-entropy alloy and an Al melt was studied. The major findings obtained are as following. > The dissolution of Al into the HEA cause selective attack of the constituent phases. > A nanocrystalline layer and Al{sub 13}Cr{sub 2} precipitation were found at the interface. > The structure and chemical composition of the solidified Al were also modified. - Abstract: This study investigates the interfacial reaction between an as-cast multicomponent FeCrNiCoMnAl high-entropy alloy (HEA) and an Al melt at 700 deg. C. The microstructure, phase identification, and chemical composition were analyzed by using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), transmission electron microscopy (TEM) and electron back scattering diffraction (EBSD). The results showed that the contact between the solid substrate and the Al melt resulted in the formation of a region with complicated microstructure at the interface. The dissolution of the substrate alloying elements into the Al melt also caused chemical composition and phase changes in the solidified Al crust.

  17. Density of Liquid Binary Ni-W Alloys Measured by Modified Sessile Drop Method%用改良静滴法测量液态Ni-W二元合金的密度

    Institute of Scientific and Technical Information of China (English)

    方亮; 肖锋; 陶再南

    2004-01-01

    In order ot provide a scientific base for studying the shrinkage, transport phenomena and macrosegregation during the solidification of an alloy, the density of liquid binary Ni-W alloys with tungsten concentration from 0 to 15 mass% was measured by a modified sessile drop method. It has been found that the density of the liquid Ni-W alloys decreases with increasing temperature, but increases with the increase of tungsten concentration in the alloys. The molar volume of liquid Ni-W binary alloys increases with the increase of temperature and tungsten concentration. The partial molar volume of tungsten in Ni-W binary alloy has been evaluated approximately as (10.80-1.35× 10-3T) × 10-6 m3·mol-1.%为了给研究合金在凝固过程中发生收缩、迁移现象和偏析提供科学依据,我们用改良静滴法对钨浓度为0到15%的液态Ni-W二元合金的密度进行了测量.结果表明:Ni-W二元合金的液态密度随温度的增加而减少,但随合金中钨浓度的增加而增加;液态Ni-W二元合金的摩尔体积随温度和合金中钨浓度的增加而增加.金属钨在Ni-W二元合金中的偏摩尔体积约为(10.80-1.35×10-3T)×10-6m3·mol-1.

  18. Fundamentals of Liquid Processing in Low Earth Orbit: From Thermophysical Properties to Microstructure Formation in Metallic Alloys

    Science.gov (United States)

    Fecht, Hans-Jörg; Wunderlich, Rainer K.

    2017-08-01

    Materials science, as an interdisciplinary field with significant attention paid to nanoscience and nanotechnology in recent years, is generally concerned with the synthesis, atomic structure, chemical element distribution and various favorable properties of solid materials and structures. While solid-state processing conditions are generally insensitive to gravity effects, liquid-state processing depends considerably on gravity, leading to strong impact of interfacial phenomena (liquid/solid, liquid/liquid), momentum, heat and mass transport on solidification patterns, as well as further consequences regarding phase selection during solidification and growth conditions, segregation, etc. In this regard, it is interesting to note that almost 100% of all metallic products are, at some stage, produced through solidification and casting processes. Experiments on metallic liquids excluding the effects of gravity—which is achievable through processing in space, thus reducing gravity effects to micro-levels—allow benchmark experiments and the opening of a new realm of experimental possibilities to investigate basic features of the liquid state. The basics and several experimental results are discussed including recent experiments on long time scales under high temperature and containerless processing conditions on board the International Space Station.

  19. Lattice vibrations study of Ga{sub 1-x}In{sub x}As{sub y}Sb{sub 1-y} quaternary alloys with low (In, As) content grown by liquid phase epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Olvera-Herandez, J [Centro de Investigacion en Dispositivos Semiconductores (CIDS), BUAP, Puebla, Pue. 72570 (Mexico); Olvera-Cervantes, J [Centro de Investigacion en Dispositivos Semiconductores (CIDS), BUAP, Puebla, Pue. 72570 (Mexico); Rojas-Lopez, M [Centro de Investigacion en BiotecnologIa Aplicada (CIBA), IPN, Tlaxcala, Tlax. 72160 (Mexico); Navarro-Contreras, H [Instituto de Investigacion en Comunicacion Optica (IICO), UASLP, 78100, San Luis PotosI, S.L.P. (Mexico); Vidal, M A [Instituto de Investigacion en Comunicacion Optica (IICO), UASLP, 78100, San Luis PotosI, S.L.P. (Mexico); Anda, F de [Instituto de Investigacion en Comunicacion Optica (IICO), UASLP, 78100, San Luis PotosI, S.L.P. (Mexico)

    2006-01-01

    Raman scattering spectroscopy was used to measure and analyze the lattice vibrations in some quaternary Ga{sub 1-x}In{sub x}As{sub y}Sb{sub 1-y} alloys with low (In, As) contents (0.03 liquid phase epitaxy on (001) GaSb substrates at 540{sup 0}C. High Resolution X-Ray Diffraction results showed profiles associated with a quaternary layer lattice matched to the GaSb substrate as obtained from the (004) reflection. The experimental diffractograms were simulated to estimate alloy composition, thickness and lattice mismatch of the layer. Raman scattering results show phonon frequencies associated to the TO and LO GaAs-like modes as well as GaSb + InAs-like mode, which are characteristic of this quaternary alloy. The As content dependence of the phonon frequency measured in this alloy for low (In, As) contents agree well with the modified Random-Element Isodisplacement (REI) model and also with other available experimental reports. This method can also be used to estimate alloy compositions for this kind of quaternary alloys.

  20. Tungsten Alloy Outgassing Measurements

    CERN Document Server

    Rutherfoord, John P; Shaver, L

    1999-01-01

    Tungsten alloys have not seen extensive use in liquid argon calorimeters so far. Because the manufacturing process for tungsten is different from the more common metals used in liquid argon there is concern that tungsten could poison the argon thereby creating difficulties for precision calorimetry. In this paper we report measurements of outgassing from the tungsten alloy slugs proposed for use in the ATLAS FCal module and estimate limits on potential poisoning with reasonable assumptions. This estimate gives an upper limit poisoning rate of liquid argon equal to the volume of tungsten slugs.

  1. Surface Tension Calculation of Undercooled Alloys

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Based on the Butler equation and extrapolated thermodynamic data of undercooled alloys from those of liquid stable alloys, a method for surface tension calculation of undercooled alloys is proposed. The surface tensions of liquid stable and undercooled Ni-Cu (xNi=0.42) and Ni-Fe (xNi=0.3 and 0.7) alloys are calculated using STCBE (Surface Tension Calculation based on Butler Equation) program. The agreement between calculated values and experimental data is good enough, and the temperature dependence of the surface tension can be reasonable down to 150-200 K under the liquid temperature of the alloys.

  2. Measurement of solid-liquid interfacial energy in the In-Bi eutectic alloy at low melting temperature

    Energy Technology Data Exchange (ETDEWEB)

    Marasli, N [Department of Physics, Faculty of Arts and Sciences, Erciyes University, 38039 Kayseri (Turkey); Akbulut, S [Institute of Science and Technology, Department of Physics, Erciyes University, 38039 Kayseri (Turkey); Ocak, Y [Department of Physics, Faculty of Arts and Sciences, Erciyes University, 38039 Kayseri (Turkey); Keslioglu, K [Department of Physics, Faculty of Arts and Sciences, Erciyes University, 38039 Kayseri (Turkey); Boeyuek, U [Institute of Science and Technology, Department of Physics, Erciyes University, 38039 Kayseri (Turkey); Kaya, H [Department of Science Education, Education Faculty, Erciyes University, 38039 Kayseri (Turkey); Cadirli, E [Department of Physics, Faculty of Arts and Sciences, Nigde University, Nigde (Turkey)

    2007-12-19

    The Gibbs-Thomson coefficient and solid-liquid interfacial energy of the solid In solution in equilibrium with In Bi eutectic liquid have been determined to be (1.46 {+-} 0.07) x 10{sup -7} K m and (40.4 {+-} 4.0) x 10{sup -3} J m{sup -2} by observing the equilibrated grain boundary groove shapes. The grain boundary energy of the solid In solution phase has been calculated to be (79.0 {+-} 8.7) x 10{sup -3} J m{sup -2} by considering force balance at the grain boundary grooves. The thermal conductivities of the In-12.4 at.% Bi eutectic liquid phase and the solid In solution phase and their ratio at the eutectic melting temperature (72 deg. C) have also been measured with radial heat flow apparatus and Bridgman-type growth apparatus.

  3. Electrodeposition and magnetic characterization of iron and iron-silicon alloys from the ionic liquid 1-butyl-1-methylpyrrolidinium trifluoromethylsulfonate.

    Science.gov (United States)

    Giridhar, Pulletikurthi; Weidenfeller, Bernd; El Abedin, Sherif Zein; Endres, Frank

    2014-11-10

    The electrodeposition of soft magnetic iron and iron-silicon alloys for magnetic measurements is presented. The preparation of these materials in 1-butyl-1-methylpyrrolidinium trifluoromethylsulfonate, [Py1,4]TfO, at 100 °C with FeCl2 and FeCl2 +SiCl4 was studied by using cyclic voltammetry. Constant-potential electrolysis was carried out to deposit either Fe or FeSi, and deposits of approximately 10 μm thicknesses were obtained. By using scanning electron microscopy and X-ray diffraction, the microstructure and crystallinity of the deposits were investigated. Grain sizes in the nanometer regime (50-80 nm) were found and the presence of iron-silicon alloys was verified. Frequency-dependent magnetic polarizations, coercive forces, and power losses of some deposits were determined by using a digital hysteresis recorder. Corresponding to the small grain sizes, the coercive forces are around 950-1150 A m(-1) and the power losses were at 6000 J m(-3), which is much higher than in commercial Fe(3.2 wt %)Si electrical steel. Below a polarization of 1.8 T, the power losses are mainly caused by domain wall movements and, above 1.8 T, by rotation of magnetic moments as well as domain wall annihilation and recreation.

  4. Ultrasonic-electrodeposition of PtPd alloy nanoparticles on ionic liquid-functionalized graphene paper: towards a flexible and versatile nanohybrid electrode

    Science.gov (United States)

    Sun, Yimin; Zheng, Huaming; Wang, Chenxu; Yang, Mengmeng; Zhou, Aijun; Duan, Hongwei

    2016-01-01

    Here we fabricate a new type of flexible and versatile nanohybrid paper electrode by ultrasonic-electrodeposition of PtPd alloy nanoparticles on freestanding ionic liquid (IL)-functionalized graphene paper, and explore its multifunctional applications in electrochemical catalysis and sensing systems. The graphene-based paper materials demonstrate intrinsic flexibility, exceptional mechanical strength and high electrical conductivity, and therefore can serve as an ideal freestanding flexible electrode for electrochemical devices. Furthermore, the functionalization of graphene with IL (i.e., 1-butyl-3-methylimidazolium tetrafluoroborate) not only increases the electroactive surface area of a graphene-based nanohybrid paper electrode, but also improves the adhesion and dispersion of metal nanoparticles on the paper surface. These unique attributes, combined with the merits of an ultrasonic-electrodeposition method, lead to the formation of PtPd alloy nanoparticles on IL-graphene paper with high loading, uniform distribution, controlled morphology and favourable size. Consequently, the resultant nanohybrid paper electrode exhibits remarkable catalytic activity as well as excellent cycle stability and improved anti-poisoning ability towards electrooxidation of fuel molecules such as methanol and ethanol. Furthermore, for nonenzymatic electrochemical sensing of some specific biomarkers such as glucose and reactive oxygen species, the nanohybrid paper electrode shows high selectivity, sensitivity and biocompatibility in these bio-catalytic processes, and can be used for real-time tracking hydrogen peroxide secretion by living human cells. All these features demonstrate its promising application as a versatile nanohybrid electrode material in flexible and lightweight electrochemical energy conversion and biosensing systems such as bendable on-chip power sources, wearable/implantable detectors and in vivo micro-biosensors.Here we fabricate a new type of flexible and

  5. Metastable alloy nanoparticles, metal-oxide nanocrescents and nanoshells generated by laser ablation in liquid solution: influence of the chemical environment on structure and composition.

    Science.gov (United States)

    Scaramuzza, Stefano; Agnoli, Stefano; Amendola, Vincenzo

    2015-11-14

    Alloy nanoparticles are characterized by the combination of multiple interesting properties, which are attractive for technological and scientific purposes. A frontier topic of this field is nanoalloys with compositions not thermodynamically allowed at ordinary temperature and pressure (i.e. metastable), because they require out-of-equilibrium synthetic approaches. Recently, laser ablation synthesis in solution (LASiS) was successfully applied for the realization of metastable nanoalloys because of the fast kinetics of nanoparticle formation. However, the role played by the chemical environment on the final composition and structure of laser generated nanoalloys still has to be fully elucidated. Here, we investigated the influence of different synthetic conditions on the LASiS of metastable nanoalloys composed of Au and Fe, such as the use of water instead of ethanol, the bubbling of inert gases and the addition of a few vol% of H2O2 and H2O. The two elements showed different reactivity when LASiS was performed in water instead of ethanol, while minor effects were observed from bubbling pure gases such as N2, Ar and CO2 in the liquid solution. Moreover, the plasmonic response and the structure of the nanoalloys were sensibly modified by adding H2O2 to water. We also found that nanoparticle production is dramatically influenced just by adding 0.2% of H2O in ethanol. These results suggest that the formation of a cavitation bubble with long lifetime and large size during LASiS is useful for the preservation of the metastable alloy composition, whereas an oxidative environment hampers the formation of metastable alloy nanoparticles. Overall, by acting on the type of solvent and solutes, we were able to switch from a traditional synthetic approach for the composition of Au-Fe nanoalloys to one using a reactive environment, which gives unconventional structures such as metal@iron-oxide nanoshells and nanocrescents of oxide supported on metal nanospheres. These results

  6. Role of Dissolved and Molecular Oxygen on Cu and PtCu Alloy Particle Structure during Laser Ablation Synthesis in Liquids.

    Science.gov (United States)

    Marzun, Galina; Bönnemann, Helmut; Lehmann, Christian; Spliethoff, Bernd; Weidenthaler, Claudia; Barcikowski, Stephan

    2017-05-05

    The role of molecular oxygen dissolved in the solvent is often discussed as being an influential factor on particle oxidation during pulsed laser ablation in liquids. However, the formation of the particles during laser synthesis takes place under extreme conditions that enable the decomposition of the liquid medium. Reactive species of the solvent may then affect particle formation due to a chemical reaction in the reactive plasma. Experimental results show a difference between the role of dissolved molecular oxygen and the contribution from the oxygen in water molecules. Using a metallic Cu target in air-saturated water, laser ablation led to 20.5 wt % Cu, 11.5 wt % Cu2 O, and 68 wt % CuO nanoparticles, according to X-ray diffraction results. In contrast to particles obtained in air-saturated water, no CuO was observed in the colloid synthesized in a Schlenk ablation chamber in completely oxygen-free water. Under these conditions, less-oxidized nanoparticles (25 wt % Cu and 75 wt % Cu2 O) were synthesized. The results show that nanoparticle oxidation during laser synthesis is mainly caused by reactive oxygen species from the decomposition of water molecules. However, the addition of molecular oxygen promotes particle oxidation. Storage of the Cu colloid in the presence of dissolved oxygen leads, due to aging, to nanostructures with a higher oxidation state than the freshly prepared colloid. The XRD pattern of the sample prepared in air-saturated acetone showed no crystalline phases, which is possibly due to small crystallites or low particle concentration. Concentration of the particles by centrifugation showed that in the large fraction (>20 nm), even less oxidized nanoparticles (46 wt % Cu and 54 wt % Cu2 O) were present, although the solubility of molecular oxygen is higher in acetone than in water. The nanoparticles in acetone were stable due to a Cu-catalyzed graphite layer formed on their surfaces. The influence of the solvent

  7. Structure of the glass-forming metallic liquids by ab-initio and classical molecular dynamics, a case study: Quenching the Cu{sub 60}Ti{sub 20}Zr{sub 20} alloy

    Energy Technology Data Exchange (ETDEWEB)

    Amokrane, S.; Ayadim, A.; Levrel, L. [Groupe “Physique des Liquides et Milieux Complexes,” Faculté des Sciences et Technologie, Université Paris-Est (Créteil), 61 av. du Général de Gaulle, 94010 Créteil Cedex (France)

    2015-11-21

    We consider the question of the amorphization of metallic alloys by melt quenching, as predicted by molecular dynamics simulations with semi-empirical potentials. The parametrization of the potentials is discussed on the example of the ternary Cu-Ti-Zr transition metals alloy, using the ab-initio simulation as a reference. The pair structure in the amorphous state is computed from a potential of the Stillinger-Weber form. The transferability of the parameters during the quench is investigated using two parametrizations: from solid state data, as usual and from a new parametrization on the liquid structure. When the adjustment is made on the pair structure of the liquid, a satisfactory transferability is found between the pure components and their alloys. The liquid structure predicted in this way agrees well with experiment, in contrast with the one obtained using the adjustment on the solid. The final structure, after quenches down to the amorphous state, determined with the new set of parameters is shown to be very close to the ab-initio one, the latter being in excellent agreement with recent X-rays diffraction experiments. The corresponding critical temperature of the glass transition is estimated from the behavior of the heat capacity. Discussion on the consistency between the structures predicted using semi-empirical potentials and ab-initio simulation, and comparison of different experimental data underlines the question of the dependence of the final structure on the thermodynamic path followed to reach the amorphous state.

  8. Behavior of steels in flowing liquid PbBi eutectic alloy at 420-600 deg. C after 4000-7200 h

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, G. [Forschungszentrum Karlsruhe GmbH, Institute for Pulsed Power and Microwave Technology, P.O. Box 3640, D-76021 Karlsruhe (Germany); Heinzel, A. [Forschungszentrum Karlsruhe GmbH, Institute for Pulsed Power and Microwave Technology, P.O. Box 3640, D-76021 Karlsruhe (Germany)]. E-mail: annette.heinzel@ihm.fzk.de; Konys, J. [Forschungszentrum Karlsruhe GmbH, Institute for Pulsed Power and Microwave Technology, P.O. Box 3640, D-76021 Karlsruhe (Germany); Schumacher, G. [Forschungszentrum Karlsruhe GmbH, Institute for Pulsed Power and Microwave Technology, P.O. Box 3640, D-76021 Karlsruhe (Germany); Weisenburger, A. [Forschungszentrum Karlsruhe GmbH, Institute for Pulsed Power and Microwave Technology, P.O. Box 3640, D-76021 Karlsruhe (Germany); Zimmermann, F. [Forschungszentrum Karlsruhe GmbH, Institute for Pulsed Power and Microwave Technology, P.O. Box 3640, D-76021 Karlsruhe (Germany); Engelko, V. [Efremov Institute of Electrophysical Apparatus, 189631 St. Petersburg (Russian Federation); Rusanov, A. [IPPE, Bondarenko Square 1, 249020 Obninsk, Kaluga Region (Russian Federation); Markov, V. [CRISM ' PROMETEY' , 193015 St. Petersburg (Russian Federation)

    2004-11-01

    This paper presents the results of steel exposure up to 7200 h in flowing LBE at elevated temperatures and is a follow-up paper of that with results of an exposure of up to 2000 h. The examined AISI 316 L, 1.4970 austenitic and MANET 10Cr martensitic steels are suitable as a structural material in LBE (liquid eutectic Pb{sub 45}Bi{sub 55}) up to 550 deg. C, if 10{sup -6} wt% of oxygen is dissolved in the LBE. The martensitic steel develops a thick magnetite and spinel layer while the austenites have thin spinel surface layers at 420 deg. C and thick oxide scales like the martensitic steel at 550 deg. C. The oxide scales protect the steels from dissolution attack by LBE during the whole test period of 7200 h. Oxide scales that spall off are replaced by new protective ones. At 600 deg. C severe attack occurs already after 2000 and 4000 h of exposure. Steels with 8-15 wt% Al alloyed into the surface suffer no corrosion attack at all experimental temperatures and exposure times.

  9. Electrodeposition of diamond-like carbon films on titanium alloy using organic liquids: Corrosion and wear resistance

    Energy Technology Data Exchange (ETDEWEB)

    Falcade, Tiago, E-mail: tiago.falcade@ufrgs.br [Federal University of Rio Grande do Sul, 9500 Bento Goncalves Ave. Sector 4, Building 75, 2nd floor, Porto Alegre, RS (Brazil); Shmitzhaus, Tobias Eduardo, E-mail: tobiasschmitzhaus@gmail.com [Federal University of Rio Grande do Sul, Porto Alegre, RS (Brazil); Gomes dos Reis, Otavio, E-mail: otavio_gomes214@hotmail.com [Federal University of Rio Grande do Sul, Porto Alegre, RS (Brazil); Vargas, Andre Luis Marin; Huebler, Roberto [Pontificia Universidade Catolica do Rio Grande do Sul (Brazil); Mueller, Iduvirges Lourdes, E-mail: ilmuller@ufrgs.br [Federal University of Rio Grande do Sul, Porto Alegre, RS (Brazil); Fraga Malfatti, Celia de, E-mail: celia.malfatti@ufrgs.br [Federal University of Rio Grande do Sul, Porto Alegre, RS (Brazil)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer The electrodeposition may be conducted at room temperature. Black-Right-Pointing-Pointer The DLC films have good resistance to corrosion in saline environments. Black-Right-Pointing-Pointer The films have lower coefficient of friction than the uncoated substrate. Black-Right-Pointing-Pointer The abrasive wear protection is evident in coated systems. - Abstract: Diamond-like carbon (DLC) films have been studied as coatings for corrosion protection and wear resistance because they have excellent chemical inertness in traditional corrosive environments, besides presenting a significant reduction in coefficient of friction. Diamond-like carbon (DLC) films obtained by electrochemical deposition techniques have attracted a lot of interest, regarding their potential in relation to the vapor phase deposition techniques. The electrochemical deposition techniques are carried out at room temperature and do not need vacuum system, making easier this way the technological transfer. At high electric fields, the organic molecules polarize and react on the electrode surface, forming carbon films. The aim of this work was to obtain DLC films onto Ti6Al4V substrate using as electrolyte: acetonitrile (ACN) and N,N-dimethylformamide (DMF). The films were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), Raman spectroscopy, potentiodynamic polarization and wear tests. The results show that these films can improve, significantly, the corrosion resistance of titanium and its alloys and their wear resistance.

  10. Measurement and Analysis of Liquid Density of NiCoAlMo Quarternary Alloys%四元合金NiCoAlMo液态密度的测量与分析

    Institute of Scientific and Technical Information of China (English)

    唐先智; 方亮; 肖锋; 陶再南

    2011-01-01

    用改良静滴法对钼浓度在0%到10%(质量分数)的NiCoAlMo四元合金的液态密度进行了测量,NiCoA1Mo合金的Ni:Co:A1摩尔比与商用镍基超合金TMS75、INCO713、CM247LC和CMSX-4的Ni:Co:Al摩尔比接近(χNi:χCo:χAl=73:12:15).结果表明:液态密度随温度的增加而减小,随合金中钼浓度的增加而增加;液态NiCoAlMo四元合金的摩尔体积随温度和合金中钼浓度的增加而增加,与理想混合相比,呈负偏差.由镍基二元合金中镍、钻、铝、钼4个元素的偏摩尔体积计算获得的NiCoAlMo四元合金的液态密度与实验测量密度吻合良好,表明在误差范围内,多元镍基合金的液态密度可以通过二元镍基合金中相应元素的偏摩尔体积进行预测估计.%The density of liquid NiCoAlMo quaternary alloy with a fixed molar ratio of Ni:Co:Al (χNi:χCo:χAl≈73:12:15) which is close to the average value of the commercial Ni-based superalloys TMS75, INCO713, CM247LC and CMSX-4, and molybdenum concentration change from 0% to 10% (mass fraction) was measured by a modified sessile drop method. It is found that the density of the liquid NiCoA1Mo quaternary alloy decreases with increasing of temperature, but increases with the increase of molybdenum concentration in the alloys. The molar volume of liquid NiCoAIMo quaternary alloy increases with the increase of temperature and molybdenum concentration, and shows a negative deviation from the ideal linear mixing. The liquid density of NiCoA1Mo quaternary alloy calculated from the partial molar volumes of nickel, cobalt, aluminum and molybdenum in the corresponding Ni-bases binary alloy are in good agreement with the experimental results; it means that within the error tolerance range the density of liquid Ni-based multi-component alloys can be predicted from the partial volumes of elements in Ni-based binary alloys in liquid state.

  11. Phase Boundary Propagation in Li-Alloying Battery Electrodes Revealed by Liquid-Cell Transmission Electron Microscopy.

    Science.gov (United States)

    Leenheer, Andrew J; Jungjohann, Katherine L; Zavadil, Kevin R; Harris, Charles T

    2016-06-28

    Battery cycle life is directly influenced by the microstructural changes occurring in the electrodes during charge and discharge cycles. Here, we image in situ the nanoscale phase evolution in negative electrode materials for Li-ion batteries using a fully enclosed liquid cell in a transmission electron microscope (TEM) to reveal early degradation that is not evident in the charge-discharge curves. To compare the electrochemical phase transformation behavior between three model materials, thin films of amorphous Si, crystalline Al, and crystalline Au were lithiated and delithiated at controlled rates while immersed in a commercial liquid electrolyte. This method allowed for the direct observation of lithiation mechanisms in nanoscale negative electrodes, revealing that a simplistic model of a surface-to-interior lithiation front is insufficient. For the crystalline films, a lithiation front spread laterally from a few initial nucleation points, with continued grain nucleation along the growing interface. The intermediate lithiated phases were identified using electron diffraction, and high-resolution postmortem imaging revealed the details of the final microstructure. Our results show that electrochemically induced solid-solid phase transformations can lead to highly concentrated stresses at the laterally propagating phase boundary which should be considered for future designs of nanostructured electrodes for Li-ion batteries.

  12. Separation in liquid and the formation of supersaturated solid solutions in Fe-Cu alloys upon rapid laser melting

    Science.gov (United States)

    Kharanzhevskiy, E. V.

    2016-09-01

    The structure of compacted specimens produced using the rapid laser melting of ultradispersed Fe-50 wt % Cu powders has been studied. The original powder was produced via the mechanical milling of iron and copper powders in a planetary-type ball mill. It has been found that the structure of the compacted specimens produced using rapid laser melting exhibits signs of the initial stages of separation in supercooled liquid. It has been shown using X-ray diffraction analysis as well as scanning and transmission electron microscopy that the final structure contains a supersaturated (Fe; Cu) solid solution formed from the high-speed movement of the solidification front and the nonequilibrium capture of copper by the moving front.

  13. Oxidation mechanism of a Fe-9Cr-1Mo steel by liquid Pb-Bi eutectic alloy (Part I)

    Energy Technology Data Exchange (ETDEWEB)

    Martinelli, L. [CEA, DEN, Service de la Corrosion et du Comportement des Materiaux dans leur Environnement, F-91191 Gif sur Yvette (France)], E-mail: laure.martinelli@cea.fr; Balbaud-Celerier, F.; Terlain, A. [CEA, DEN, Service de la Corrosion et du Comportement des Materiaux dans leur Environnement, F-91191 Gif sur Yvette (France); Delpech, S. [CNRS, UMR 7575 Ecole Nationale superieure de Chimie de Paris, Laboratoire d' Electrochimie et de Chimie Analytique, 11 rue Pierre et Marie Curie 75231 Paris (France); Santarini, G. [CEA, Cabinet du Haut-Commisaire, F-91191 Gif sur Yvette (France); Favergeon, J.; Moulin, G. [CNRS, centre de recherche de Royallieu FRE CNRS 2833, Laboratoire Roberval, 20529-60205 Compiegne (France); Tabarant, M. [CEA, DEN, Service de Chimie Physique, F- 91191 Gif sur Yvette (France); Picard, G. [CNRS, UMR 7575 Ecole Nationale superieure de Chimie de Paris, Laboratoire d' Electrochimie et de Chimie Analytique, 11 rue Pierre et Marie Curie 75231 Paris (France)

    2008-09-15

    This paper is the first part of a global study on the oxidation process of a Fe-9Cr-1Mo martensitic steel (T91) in static liquid Pb-Bi. It focuses on the oxygen transport mode across the oxide scale. The oxide layer has a duplex structure composed of an internal Fe-Cr spinel layer and an external magnetite layer. Oxygen 18 tracer experiments are performed: they show that the magnetite layer grows at the Pb-Bi/ oxide interface whereas the Fe-Cr spinel layer grows at the metal/oxide interface. Oxygen seems to diffuse across the oxide scale dissolved inside nanometric lead penetrations called nano-channels. Specific experiments are performed to characterize the nano-channels.

  14. Study of the removal mechanism of magnesium from Al-Si liquid alloys using silica base minerals injection; Estudio del mecanismo de eliminacion de magnesio de aleaciones Al-Si en estado liquido mediante inyeccion de minerales base silice

    Energy Technology Data Exchange (ETDEWEB)

    Munoz-Arroyo, R.; Escobedo-Bocardo, J. C.; Hernande-Garcia, H. M.; Cortes-Hernandez, D. A.; Terrones-Maldonado, M.; Rodriguez-Pulido, A.; Hernandez-Pinero, J. L.

    2010-07-01

    In order to eliminate magnesium from an A 380 Al-Si alloy at 750 degree centigrade, the submerged powder injection method, using an inert carrier gas (Ar), was applied. The injected powders in the liquid aluminum bath were zeolite, silica and mixtures of zeolite-silica minerals. For each experiment the response variables were: eliminated magnesium versus injection time and quantity of drosses produced. Chemical analysis by atomic absorption spectrometry showed that mixtures of silica-zeolite 66:34 wt% have the best results with regarding to the removal magnesium from 1 to 0.0066 wt%. During the elimination of magnesium complex stoichiometry compounds were formed due to the reactions among zeolite, water steam and liquid aluminum. These compounds were analyzed by XRD, SEM and TEM. The results obtained, along with using the FactSage 6 thermodynamic software, allowed to elucidate the reaction mechanism between the minerals used and liquid aluminum. (Author)

  15. Design, Selection and Application of High Efficient Complex Alloys

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The design, selection and application principles of complex alloys according to the requirements of making low-alloy steels are di scussed. The designed complex alloys containing calcium, barium, magne sium, strontium, rare earth elements, etc. should not only be able to deoxidize, desulphurize and refine liquid steel, but also alloy it. Th e application principles of alloys are as follows: using Si-Mn or Si-M n-Al alloys for pre-deoxidizing, Si-Al-Ba or Si-Al-Ca-Ba alloys for fi nal deoxidizing and Si-Ca-Ba-Mg(Sr) alloys for refining.

  16. Experimental partitioning of Zr, Ti, and Nb between silicate liquid and a complex noble metal alloy and the partitioning of Ti between perovskite and platinum metal

    Science.gov (United States)

    Jurewicz, Stephen R.; Jones, John H.

    1993-01-01

    El Goresy et al.'s observation of Nb, Zr, and Ta in refractory platinum metal nuggets (RPMN's) from Ca-Al-rich inclusions (CAI's) in the Allende meteorite led them to propose that these lithophile elements alloyed in the metallic state with noble metals in the early solar nebula. However, Grossman pointed out that the thermodynamic stability of Zr in the oxide phase is vastly greater than metallic Zr at estimated solar nebula conditions. Jones and Burnett suggested this discrepancy may be explained by the very non-ideal behavior of some lithophile transition elements in noble metal solutions and/or intermetallic compounds. Subsequently, Fegley and Kornacki used thermodynamic data taken from the literature to predict the stability of several of these intermetallic compounds at estimated solar nebula conditions. Palme and Schmitt and Treiman et al. conducted experiments to quantify the partitioning behavior of certain lithophile elements between silicate liquid and Pt-metal. Although their results were somewhat variable, they did suggest that Zr partition coefficients were too small to explain the observed 'percent' levels in some RPMN's. Palme and Schmitt also observed large partition coefficients for Nb and Ta. No intermetallic phases were identified. Following the work of Treiman et al., Jurewicz and Jones performed experiments to examine Zr, Nb, and Ti partitioning near solar nebula conditions. Their results showed that Zr, Nb, and Ti all have an affinity for the platinum metal, with Nb and Ti having a very strong preference for the metal. The intermetallic phases (Zr,Fe)Pt3, (Nb,Fe)Pt3, and (Ti,Fe)Pt3 were identified. Curiously, although both experiments and calculations indicate that Ti should partition strongly into Pt-metal (possibly as TiPt3), no Ti has ever been observed in any RPMN's. Fegley and Kornacki also noticed this discrepancy and hypothesized that the Ti was stabilized in perovskite which is a common phase in Allende CAI's.

  17. Differential Scanning Calorimetry (DSC) and Thermodynamic Prediction of Liquid Fraction vs Temperature for Two High-Performance Alloys for Semi-Solid Processing (Al-Si-Cu-Mg (319s) and Al-Cu-Ag (201))

    Science.gov (United States)

    Zhang, Duyao; Atkinson, Helen V.; Dong, Hongbiao; Zhu, Qiang

    2017-10-01

    There is a need to extend the application of semi-solid processing (SSP) to higher performance alloys such as 319s (Al-Si-Cu-Mg) and 201 (Al-Cu-Ag). The melting of these two alloys was investigated using differential scanning calorimetry (DSC) and thermodynamic prediction. The alloys had been processed by magneto-hydrodynamic (MHD) stirring before receipt to produce a microstructure suitable for SSP. The DSC results for the as-received MHD material were compared with those for material which has been taken through a complete DSC cycle and then reheated for a second DSC run. The effects of microsegregation were then analyzed. A higher liquid fraction for a particular temperature is found in the second DSC run than the first. Microstructural observations suggest this is because the intermetallics which form during the first cooling cycle tend to co-located. Quaternary and ternary reactions then occur during the second DSC heat and the co-location leads to enhanced peaks. The calculated liquid fraction is lower with 10 K/min DSC heating rate comparing with 3 K/min at a given temperature. The DSC scan rate must therefore be carefully considered if it is to be used to identify temperature parameters or the suitability of alloys for SSP. In addition, the starting material for DSC must represent the starting material for the SSP. With thermodynamic prediction, the equilibrium condition will provide better guidance for the thixoforming of MHD stirred starting material than the Scheil condition. The Scheil mode approximates more closely with a strongly microsegregated state.

  18. Alloy element redistribution during sintering of powder metallurgy steels

    OpenAIRE

    Tahir, Abdul Malik

    2014-01-01

    Homogenization of alloying elements is desired during sintering of powder metallurgy components. The redistribution processes such as penetration of liquid phase into the interparticle/grain boundaries of solid particles and subsequent solid-state  diffusion of alloy element(s) in the base powder, are important for the effective homogenization of alloy element(s) during liquid phase sintering of the mixed powders. The aim of this study is to increase the understanding of alloy element redistr...

  19. Technique of Aluminum Alloy Composite by Inversion Casting

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The influence of the temperature of liquid aluminum alloy, the dipping time in liquid alloy and the thickness of base strips on the solidified layer was studied during the process of producing aluminum alloy composite strips used in automobile radiator with inversion casting. It is concluded that there is welding as well as diffusion of alloying elements between the base strip and the coating. Experiments proved that the interface has a good bonding.

  20. Liquid metal enabled microfluidics.

    Science.gov (United States)

    Khoshmanesh, Khashayar; Tang, Shi-Yang; Zhu, Jiu Yang; Schaefer, Samira; Mitchell, Arnan; Kalantar-Zadeh, Kourosh; Dickey, Michael D

    2017-03-14

    Several gallium-based liquid metal alloys are liquid at room temperature. As 'liquid', such alloys have a low viscosity and a high surface tension while as 'metal', they have high thermal and electrical conductivities, similar to mercury. However, unlike mercury, these liquid metal alloys have low toxicity and a negligible vapor pressure, rendering them much safer. In comparison to mercury, the distinguishing feature of these alloys is the rapid formation of a self-limiting atomically thin layer of gallium oxide over their surface when exposed to oxygen. This oxide layer changes many physical and chemical properties of gallium alloys, including their interfacial and rheological properties, which can be employed and modulated for various applications in microfluidics. Injecting liquid metal into microfluidic structures has been extensively used to pattern and encapsulate highly deformable and reconfigurable electronic devices including electrodes, sensors, antennas, and interconnects. Likewise, the unique features of liquid metals have been employed for fabricating miniaturized microfluidic components including pumps, valves, heaters, and electrodes. In this review, we discuss liquid metal enabled microfluidic components, and highlight their desirable attributes including simple fabrication, facile integration, stretchability, reconfigurability, and low power consumption, with promising applications for highly integrated microfluidic systems.

  1. The Behavior of Temperature Decreasing and Fraction Solid Increasing in Solid-Liquid Coexisting Zone in Solidification Process of Aluminum Alloy Weld Metal

    OpenAIRE

    Shozaburo, Ohta; Kimioku, Asai; Musashi Institute of Technology

    1993-01-01

    It is the ultimate purpose of this investigation to elucidate the fundamental phenomena in cooling and solidification process and to establish reasonably the methos of estimating hot cracking sensitivity and preventing aluminum alloy weld from hot cracking. In this raport, temperature measurement was carried out by CA thermocouple in cooling and solidification process on TIG arc spot welds of commercial aluminum alloys 2024 and 5083 and various analyses were performed. On the basis of the mea...

  2. Analysis of laser alloyed surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Jacobson, D.C.; Augustyniak, W.M.; Buene, L.; Draper, C.W.; Poate, J.M.

    1981-04-01

    Surface alloys of precious metals have many advantages over bulk alloys, the most obvious of which is cost reduction due to the reduced consumption of precious metal. There are several techniques for producing surface alloys. In this paper the laser irradiation technique is presented. The following lasers: CW CO/sub 2/, Q-switched Nd-YAG, frequency double Q-switched Nd-YAG, and pulsed ruby were used to irradiate and melt thin solid films of precious metals on metal substrates. This causes the surfaces to melt to a depth of approximately 10,000A. Alloying then takes place in the liquid phase where most metals are miscible. The high quench rates obtainable by this method of melting can result in the forming of metastable alloys. This melting and regrowth process is well understood and has been discussed in the literature over the last few years. This paper deals with two binary alloy systems, Au-Ni and Pd-Ti. Surface alloys of Au-Ni with a wide range of concentrations have been produced by laser irradiation of thin Au films on Ni. These films have been analyzed using Rutherford backscattering (RBS) and channeling. Many thin film metals other than Au have also been successfully alloyed using these methods. An example of a potential application is the laser surface alloying of Pd to Ti for corrosion passivation.

  3. Heat storage in alloy transformations

    Science.gov (United States)

    Birchenall, C. E.; Gueceri, S. I.; Farkas, D.; Labdon, M. B.; Nagaswami, N.; Pregger, B.

    1981-01-01

    The feasibility of using metal alloys as thermal energy storage media was determined. The following major elements were studied: (1) identification of congruently transforming alloys and thermochemical property measurements; (2) development of a precise and convenient method for measuring volume change during phase transformation and thermal expansion coefficients; (3) development of a numerical modeling routine for calculating heat flow in cylindrical heat exchangers containing phase change materials; and (4) identification of materials that could be used to contain the metal alloys. Several eutectic alloys and ternary intermetallic phases were determined. A method employing X-ray absorption techniques was developed to determine the coefficients of thermal expansion of both the solid and liquid phases and the volume change during phase transformation from data obtained during one continuous experimental test. The method and apparatus are discussed and the experimental results are presented. The development of the numerical modeling method is presented and results are discussed for both salt and metal alloy phase change media.

  4. Bulk amorphous Mg-based alloys

    DEFF Research Database (Denmark)

    Pryds, Nini

    2004-01-01

    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...

  5. Bonding theory for metals and alloys

    CERN Document Server

    Wang, Frederick E

    2005-01-01

    Bonding Theory for Metals and Alloys exhorts the potential existence of covalent bonding in metals and alloys. Through the recognition of the covalent bond in coexistence with the 'free' electron band, the book describes and demonstrates how the many experimental observations on metals and alloys can all be reconciled. Subsequently, it shows how the individual view of metals and alloys by physicists, chemists and metallurgists can be unified. The physical phenomena of metals and alloys covered in this book are: Miscibility Gap between two liquid metals; Phase Equilibrium Diagrams; Phenomenon of Melting. Superconductivity; Nitinol; A Metal-Alloy with Memory; Mechanical Properties; Liquid Metal Embrittlement; Superplasticity; Corrosion; The author introduces a new theory based on 'Covalon' conduction, which forms the basis for a new approach to the theory of superconductivity. This new approach not only explains the many observations made on the phenomenon of superconductivity but also makes predictions that ha...

  6. Evaluation of single liquid primers with organic sulfur compound for bonding between indirect composite material and silver-palladium-copper-gold alloy.

    Science.gov (United States)

    Shimoe, Saiji; Tanoue, Naomi; Satoda, Takahiro; Murayama, Takeshi; Nikawa, Hiroki; Matsumura, Hideo

    2010-01-01

    The purpose of this study was to evaluate the effect of primers on bonding between a silver-palladium-copper-gold alloy and an indirect composite material. Cast disks were air-abraded with alumina, conditioned with one of five primers (Alloy Primer, Luna-Wing Primer, Metal Primer II, Metaltite, M.L. Primer), and bonded with a light-activated indirect composite. Shear bond strengths were determined after 20,000 times of thermocycling. The results showed that four of the primers, except the Luna-Wing Primer, were effective in enhancing the bond strength as compared with the unprimed control group. Of these four primers, Alloy Primer, Metal Primer II, and M.L. Primer exhibited significantly greater bond strengths. It can be concluded that the effectiveness of primers varies considerably according to the organic sulfur compounds added to the solvent, and that care must be taken in selecting priming agents for bonding the composite material and the silver-palladium-copper-gold alloy.

  7. Influence of alloy ingredients on mechanical properties of ternary boride hard alloy clad materials

    Institute of Scientific and Technical Information of China (English)

    LIU Fu-tian; SONG Shi-xue; YANG Jun-ru; HUANG Wei-ling; HUANG Chuan-zhen; CHENG Xin; LI Zhao-qian

    2004-01-01

    Using Mo, B-Fe alloy and Fe powders as raw materials, and adding C, Cr and Ni ingredients, respectively, or C, Cr and Ni mixed powders, ternary boride hard alloy clad materials was prepared on Q235 steel substrate by means of in-situ reaction and vacuum liquid phase sintering technology. The influence of alloy ingredients on the mechanical properties of ternary boride hard alloy clad materials was investigated. The results indicate that a mixture of 0.8% C, 5% Cr and 2% Ni ingredients gives a ternary boride hard alloy clad material with optimal mechanical properties, such as high transverse rupture strength, high hardness and good wear resistance.

  8. Transparent Analogs for Alloy Phase Studies

    Science.gov (United States)

    Frazier, D. O.; Smith, James E., Jr.

    1987-01-01

    Report describes experiments to add information to data base supporting use of transparent, partially miscible liquids and solids as analogs in studies of alloy solidification. Behavior of these materials observed directly while they undergo liquid/liquid and liquid/solid phase transformations. Light-scattering techniques used to determine phase boundaries. Transparent analogs allow observation of both solidification patterns and processes leading to those patterns, whereas metal alloys require tedious post-solidification metallographic analyses because processes not generally observed. Experiments with transparent substances safer and cheaper since conducted at much lower temperatures.

  9. Printing graphene-carbon nanotube-ionic liquid gel on graphene paper: Towards flexible electrodes with efficient loading of PtAu alloy nanoparticles for electrochemical sensing of blood glucose.

    Science.gov (United States)

    He, Wenshan; Sun, Yimin; Xi, Jiangbo; Abdurhman, Abduraouf Alamer Mohamed; Ren, Jinghua; Duan, Hongwei

    2016-01-15

    The increasing demands for portable, wearable, and implantable sensing devices have stimulated growing interest in innovative electrode materials. In this work, we have demonstrated that printing a conductive ink formulated by blending three-dimensional (3D) porous graphene-carbon nanotube (CNT) assembly with ionic liquid (IL) on two-dimensional (2D) graphene paper (GP), leads to a freestanding GP supported graphene-CNT-IL nanocomposite (graphene-CNT-IL/GP). The incorporation of highly conductive CNTs into graphene assembly effectively increases its surface area and improves its electrical and mechanical properties. The graphene-CNT-IL/GP, as freestanding and flexible substrates, allows for efficient loading of PtAu alloy nanoparticles by means of ultrasonic-electrochemical deposition. Owing to the synergistic effect of PtAu alloy nanoparticles, 3D porous graphene-CNT scaffold, IL binder and 2D flexible GP substrate, the resultant lightweight nanohybrid paper electrode exhibits excellent sensing performances in nonenzymatic electrochemical detection of glucose in terms of sensitivity, selectivity, reproducibility and mechanical properties.

  10. Free energy of mixing of an Fe-Co liquid alloy taking into account nondiagonal d-d-electron coupling in the framework of the Willis-Harrison model

    Science.gov (United States)

    Dubinin, N. E.; Vatolin, N. A.

    2016-11-01

    Within the framework of the Willis-Harrison model, the effect of taking into account d-d-electron couplings nondiagonal in the magnetic quantum number between the neighboring atoms in a transition metal on the partial pair potentials and the free energy of mixing of an Fe-Co liquid alloy near the melting temperature is investigated. It is found that an increase in the fraction of nondiagonal couplings results in a decrease in the depth of the first minimum of the partial pair potentials and in the displacement of its position towards larger r. It is shown that taking this factor into account considerably improves the agreement with experimental data of the concentration dependence of the free energy of mixing of the system under consideration.

  11. Shape-Memory-Alloy Actuator For Flight Controls

    Science.gov (United States)

    Barret, Chris

    1995-01-01

    Report proposes use of shape-memory-alloy actuators, instead of hydraulic actuators, for aerodynamic flight-control surfaces. Actuator made of shape-memory alloy converts thermal energy into mechanical work by changing shape as it makes transitions between martensitic and austenitic crystalline phase states of alloy. Because both hot exhaust gases and cryogenic propellant liquids available aboard launch rockets, shape-memory-alloy actuators exceptionally suited for use aboard such rockets.

  12. Temperature-induced liquid state change and its effects on solidiifcation of thermoelectric alloy Bi0.3Sb1.7Te3

    Institute of Scientific and Technical Information of China (English)

    Zhang Wenjin; Wu Zhan; Yu Yuan; Zu Fangqiu

    2014-01-01

    The behaviors of electrical resistivityvs temperature (ρ-T) of the molten p-type thermoelectric aloy Bi0.3Sb1.7Te3 (at.%) were explored in heating and cooling processes. An obvious hump appeared on theρ-T curve from 932℃ to 1,020℃ at the heating process, while the curve became smooth in the folowing cooling, which suggests an irreversible temperature-induced liquid-liquid structure transition (TI-LLST) occurred in the liquid aloy. Based on this judgment, solidiifcation experiments were carried out to ifnd out the effects of the different liquid states. It was veriifed that, for the melt experiencing the presumed TI-LLST, both the nucleation and growth undercooling degrees were elevated and the solidiifcation time was remarkably prolonged. On the other hand, the conifguration of Bi0.3Sb1.7Te3 phase was reifned, and its preferential orientation was weakened.

  13. Ultrasonic processing of aluminum alloys

    NARCIS (Netherlands)

    Zhang, L.

    2013-01-01

    The research in ultrasonic processing for metallurgical application shows a promising influence on improving casting properties of aluminium alloys. The principle of ultrasonic processing is introduction of acoustic waves with a frequency higher than 17 kHz into liquid metal. Several promising

  14. Liquid gallium and the eutectic gallium indium (EGaIn) alloy: Dielectric functions from 1.24 to 3.1 eV by electrochemical reduction of surface oxides

    Science.gov (United States)

    Morales, Daniel; Stoute, Nicholas A.; Yu, Zhiyuan; Aspnes, David E.; Dickey, Michael D.

    2016-08-01

    Liquid metals based on gallium are promising materials for soft, stretchable, and shape reconfigurable electromagnetic devices. The behavior of these metals relates directly to the thicknesses of their surface oxide layers, which can be determined nondestructively by ellipsometry if their dielectric functions ɛ are known. This paper reports on the dielectric functions of liquid gallium and the eutectic gallium indium (EGaIn) alloy from 1.24 to 3.1 eV at room temperature, measured by spectroscopic ellipsometry. Overlayer-induced artifacts, a continuing problem in optical measurements of these highly reactive metals, are eliminated by applying an electrochemically reductive potential to the surface of the metal immersed in an electrolyte. This technique enables measurements at ambient conditions while avoiding the complications associated with removing overlayers in a vacuum environment. The dielectric responses of both metals are closely represented by the Drude model. The EGaIn data suggest that in the absence of an oxide the surface is In-enriched, consistent with the previous vacuum-based studies. Possible reasons for discrepancies with previous measurements are discussed.

  15. 液相三元Al-Ni-Zn合金的热力学性质计算%Calculation of thermodynamic properties in liquid phase for ternary Al-Ni-Zn alloys

    Institute of Scientific and Technical Information of China (English)

    D. (Z)IVKOVI(C); 杜勇; N. TALIJAN; A. KOSTOV; Lj. BALANOVI(C)

    2012-01-01

    The results of the calculation of thermodynamic properties in liquid state for ternary Al-Ni-Zn alloys using the newest version of the general solution model for thermodynamic prediction are presented.Nine sections with different molar ratios of Ni to Zn,Zn to Al and Al to Ni were investigated in a temperature interval of 1800-2000 K.Partial and integral molar thermodynamic properties in liquid phase for the Al-Ni-Zn ternary system are determined and discussed.%将用于热力学预测的最新版本的通用模型用来计算液相三元Al-Ni-Zn合金的热力学性质.对9个具有不同Ni与Zn,Zn与Al和Al与N摩尔比的截面在1800~2000 K的热力学性质进行研究.对液相三元Al-Ni-Zn合金的局部和整体的摩尔热力学性质进行了测定,并对结果进行了讨论.

  16. Aluminum alloy

    Science.gov (United States)

    Blackburn, Linda B. (Inventor); Starke, Edgar A., Jr. (Inventor)

    1989-01-01

    This invention relates to aluminum alloys, particularly to aluminum-copper-lithium alloys containing at least about 0.1 percent by weight of indium as an essential component, which are suitable for applications in aircraft and aerospace vehicles. At least about 0.1 percent by weight of indium is added as an essential component to an alloy which precipitates a T1 phase (Al2CuLi). This addition enhances the nucleation of the precipitate T1 phase, producing a microstructure which provides excellent strength as indicated by Rockwell hardness values and confirmed by standard tensile tests.

  17. Preparation and Properties of High-quality CdSeS Alloyed Quantum Dots in Liquid Paraffin%液体石蜡体系中CdSeS三元量子点的制备及性能

    Institute of Scientific and Technical Information of China (English)

    张德龙; 李万万; 王解兵; 孙康

    2012-01-01

    采用液体石蜡为反应溶剂,油酸为Cd源的溶剂和配体,在无磷条件下通过用高温热解法合成了高质量的CdSeS三元合金量子点.用透射电子显微镜(TEM)、X射线粉末衍射仪(XRD)和能量色散X射线分析仪(EDX)等对产物的性能进行了表征.结果表明,反应温度、反应时间和Se与S的比例等因素均对量子点的生长过程及光学性能产生影响.采用该方法制得的CdSeS三元合金量子点均为立方闪锌矿结构,且形成了一种内富S外富Se的成分梯度结构,其最大发射波长可在370~ 595 nm(近紫外~橙红色)范围内连续可调,量子效率最高可达65%.该体系下制备的CdSeS三元量子点具有良好的热稳定性和光稳定性.%A phosphine-free route was successfully developed to prepare highly-quality cadmium selenium sul-fide(CdSeS) alloyed quantum dots(QDs) using paraffin liquid as the reaction solvent and oleic acid as the ligand. The effects of the reaction temperature, growth time, and the molar ratio of S to Se on the properties of the CdSeS QDs were investigated. The as-prepared alloyed CdSeS QDs with zinc-blend crystalline structure possess a broad emission spectral ranging from 370 nm to 595 nm ( from near-ultraviolet to salmon pink ) and high photoluminescence quantum yield (PLQY) up to 65%. Moreover, the as-prepared alloyed CdSeS QDs with a gradient "CdS-rich core/CdSe-rich surface" structure also demonstrate good optical stabilities against the temperature change and photobleaching, which suggests their promising application on photoelectric devices and biological fluorescent labeling.

  18. Effect of Cooling Rate on Phase Transformations in a High-Strength Low-Alloy Steel Studied from the Liquid Phase

    Science.gov (United States)

    Dorin, Thomas; Stanford, Nicole; Taylor, Adam; Hodgson, Peter

    2015-12-01

    The phase transformation and precipitation in a high-strength low-alloy steel have been studied over a large range of cooling rates, and a continuous cooling transformation (CCT) diagram has been produced. These experiments are unique because the measurements were made from samples cooled directly from the melt, rather than in homogenized and re-heated billets. The purpose of this experimental design was to examine conditions pertinent to direct strip casting. At the highest cooling rates which simulate strip casting, the microstructure was fully bainitic with small regions of pearlite. At lower cooling rates, the fraction of polygonal ferrite increased and the pearlite regions became larger. The CCT diagram and the microstructural analysis showed that the precipitation of NbC is suppressed at high cooling rates, and is likely to be incomplete at intermediate cooling rates.

  19. Metal Alloy Compositions And Process Background Of The Invention

    Science.gov (United States)

    Flemings, Merton C.; Martinez-Ayers, Raul A.; de Figueredo, Anacleto M.; Yurko, James A.

    2003-11-11

    A skinless metal alloy composition free of entrapped gas and comprising primary solid discrete degenerate dendrites homogeneously dispersed within a secondary phase is formed by a process wherein the metal alloy is heated in a vessel to render it a liquid. The liquid is then rapidly cooled while vigorously agitating it under conditions to avoid entrapment of gas while forming solid nuclei homogeneously distributed in the liquid. Agitation then is ceased when the liquid contains a small fraction solid or the liquid-solid alloy is removed from the source of agitation while cooling is continued to form the primary solid discrete degenerate dendrites in liquid secondary phase. The solid-liquid mixture then can be formed such as by casting.

  20. Interfacial properties of immiscible Co-Cu alloys

    DEFF Research Database (Denmark)

    Egry, I.; Ratke, L.; Kolbe, M.

    2010-01-01

    Using electromagnetic levitation under microgravity conditions, the interfacial properties of an Cu75Co25 alloy have been investigated in the liquid phase. This alloy exhibits a metastable liquid miscibility gap and can be prepared and levitated in a configuration consisting of a liquid cobalt......-rich core surrounded by a liquid copper-rich shell. Exciting drop oscillations and analysing the frequency spectrum, both surface and (liquid–liquid) interfacial tension can be derived from the observed oscillation frequencies. This paper briefly reviews the theoretical background and reports on a recent...

  1. Phase transformation and liquid density redistribution during solidification of Ni-based superalloy Inconel 718

    National Research Council Canada - National Science Library

    Wang Ling Gong He Zhao Haofeng Dong Jianxin Zhang Maicang

    2012-01-01

    .... It was found that significant segregation in liquid prompts high Nb phase to precipitate directly from liquid, which results in the redistribution of alloy elements and liquid density in their vicinity. The term...

  2. 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...

  3. Novel Directional Solidification Processing of Hypermonotectic Alloys

    Science.gov (United States)

    Kaukler, William; Fedoseyev, Alex

    2002-01-01

    A model has been developed that determines the size of Liquid (sub 11) droplets generated during application of ultrasonic energy (as a function of amplitude) to immiscible alloys. The initial results are in accordance with experimental results based on Succinonitrile - Glycerol "alloys" and pure tin dispersions. Future work will take into account the importance of other effects, e.g., thermo-vibrational convection, sound attenuation, viscosity variations, and compositional changes.

  4. Degassing of Aluminum Alloys Using Ultrasonic Vibration

    Energy Technology Data Exchange (ETDEWEB)

    Meek, T. T.; Han, Q.; Xu, H.

    2006-06-01

    The research was intended to lead to a better fundamental understanding of the effect of ultrasonic energy on the degassing of liquid metals and to develop practical approaches for the ultrasonic degassing of alloys. The goals of the project described here were to evaluate core principles, establish a quantitative basis for the ultrasonic degassing of aluminum alloy melts, and demonstrate the application of ultrsaonic processing during ingot casting and foundry shape casting.

  5. Long - range foundry Al composite alloys

    Directory of Open Access Journals (Sweden)

    A. D. Mekhtiev

    2014-10-01

    Full Text Available The technology of obtaining nanostructural composite aluminum alloys consists in the plasma injection of refractory nanometric particles with simultaneous two-plane magnetic dynamic mixing of the melt. Particularly important in obtaining composite aluminum matrix alloys is the provision of the introduced particles wettability with the matrix melt for forming stable adhesive bonds. Nanostructured powder components can be considered not only to be a starting product for producing nanostructural composite aluminum alloys but as an independent commerce product. Nanostructural composite metal matrix alloys make one of the most prospective structural materials of the future, and liquid-phase technologies of their obtaining are the most competitive in producing products of nanostructural composite aluminum alloys in the industrial scale.

  6. A sessile drop setup for the time-resolved synchrotron study of solid-liquid interactions: Application to intermetallic formation in 55%Al-Zn alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bernier, N., E-mail: n.bernier@yahoo.fr; De Bruyn, D.; De Craene, M.; Scheers, J.; Claessens, S. [OCAS N.V., ArcelorMittal Global R and D Gent, Pres. J.F. Kennedylaan 3, 9060 Zelzate (Belgium); Vaughan, G. B. M.; Vitoux, H.; Gleyzolle, H.; Gorges, B. [European Synchrotron Radiation Facility, BP 220, 38043 Grenoble Cedex (France)

    2014-04-28

    We introduce a dedicated setup for measuring by synchrotron diffraction in-situ crystallographic and chemical information at the solid–liquid interface. This setup mostly consists of a double-heating furnace composed of a resistive heating for the solid surface and an inductive heating to produce a liquid droplet. The available high energy and high flux beams allow the rapid reaction kinetics to be investigated with very good time resolution down to 1 ms. An application of this setup is illustrated for the growth mechanisms of intermetallic phases during the hot-dipping of steel in a 55%Al-Zn bath. Results show that the three η-Al{sub 5}Fe{sub 2}, θ-Al{sub 13}Fe{sub 4}, and α-Al{sub 8}Fe{sub 2}Si phases grow at different times and rates during the dipping process, whereas the face-centered cubic AlFe{sub 3} phase is not formed.

  7. Joining Techniques for Ferritic ODS Alloys

    Energy Technology Data Exchange (ETDEWEB)

    V.G. Krishnardula; V.G. Krishnardula; D.E. Clark; T.C. Totemeier

    2005-06-01

    This report presents results of research on advanced joining techniques for ferritic oxide-dispersion strengthened alloys MA956 and PM2000. The joining techniques studied were resistance pressure welding (also known as pressure forge welding), transient liquid phase bonding, and diffusion bonding. All techniques were shown to produce sound joints in fine-grained, unrecrystallized alloys. Post-bond heat treatment to produce a coarse-grained, recrystallized microstructure resulted in grain growth across the bondline for transient liquid phase and diffusion bonds, giving microstructures essentially identical to that of the parent alloy in the recrystallized condition. The effects of bond orientation, boron interlayer thickness, and bonding parameters are discussed for transient liquid phase and diffusion bonding. The report concludes with a brief discussion of ODS joining techniques and their applicability to GEN IV reactor systems.

  8. Glass Transitions, Semiconductor-Metal Transitions, and Fragilities in Ge -V -Te (V =As , Sb) Liquid Alloys: The Difference One Element Can Make

    Science.gov (United States)

    Wei, Shuai; Coleman, Garrett J.; Lucas, Pierre; Angell, C. Austen

    2017-03-01

    Glass-transition temperatures (Tg ) and liquid fragilities are measured along a line of constant Ge content in the system Ge-As-Te, and contrasted with the lack of glass-forming ability in the twin system Ge-Sb-Te at the same Ge content. The one composition established as free of crystal contamination in the latter system shows a behavior opposite to that of a more covalent system. The comparison of Tg vs bond density in the three systems Ge-As-chalcogen differing in chalcogen, i.e., S, Se, or Te, shows that as the chalcogen becomes more metallic, i.e., in the order S ambient pressure) melting point.

  9. Cobalt alloy ion sources for focused ion beam implantation

    Energy Technology Data Exchange (ETDEWEB)

    Muehle, R.; Doebeli, M. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Zimmermann, P. [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

    1997-09-01

    Cobalt alloy ion sources have been developed for silicide formation by focused ion beam implantation. Four eutectic alloys AuCo, CoGe, CoY and AuCoGe were produced by electron beam welding. The AuCo liquid alloy ion source was investigated in detail. We have measured the emission current stability, the current-voltage characteristics, and the mass spectrum as a function of the mission current. (author) 1 fig., 2 refs.

  10. Examination of the anisotropy of the wetting behaviour of liquid Al-Cu alloys on single crystalline oriented Al{sub 2}O{sub 3}-substrates; Untersuchung der Anisotropie im Benetzungsverhalten fluessiger Al-Cu Legierungen auf einkristallinen orientierten Al{sub 2}O{sub 3}-Substraten

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, Julianna

    2011-02-04

    The wetting behaviour of liquid Al-Cu alloys and pure metals on oriented single crystalline Al{sub 2}O{sub 3}-substrates was examined, utilising the sessile drop technique. Measurements were performed at moderate temperatures of 1100 C, where the alloys are liquid. Different Al{sub 2}O{sub 3}-surfaces were studied, which are terminated by the crystallographic planes (0001), (11 anti 20), and (1 anti 102), also called C-, A-, and R-surfaces. After deposition, pure Cu-droplets show an exponential increase of the wetting angle to a value of about 115 for all investigated Al{sub 2}O{sub 3}-surfaces. The timescale of this increase is of the order of 100 s. The effect of surface- and interfacial energies on the wetting angle is discussed considering Young's equation. The most probable reason for its time-dependence seems to be an increase of the interfacial energy due to deoxidation of the droplet. Therefore it is reasonable to regard the isotropic contact angle value as the intrinsic one of the Cu/Al{sub 2}O{sub 3} system. In contrast, the wetting angle of pure Al metal with the different Al{sub 2}O{sub 3}-substrates shows a qualitatively different behaviour. In this system, it rises from about 90 to 115 roughly for C-substrates, twice as fast as in the Cu case but to a comparable value. On the other substrates a wetting angle of about 90 establishes immediately, and no pronounced time dependence is obvious. In order to study changes in the wetting behaviour of Al-Cu-alloys, which is isotropic for Cu and anisotropic for Al-rich alloys, contact angles of Al{sub 50}Cu{sub 50}, Al{sub 30}Cu{sub 70} und Al{sub 17}Cu{sub 83} on Al{sub 2}O{sub 3} were determined. For each alloy composition the wetting angle is about 120 after 300 s. The initial values on distinct surfaces hardly differ and become non-wetting with increasing Cu-content. Hence, anisotropy decreases. To determine the work of adhesion of the solid-liquid interface, the temperature- and composition

  11. Specificity in liquid metal induced embrittlement

    CSIR Research Space (South Africa)

    Fernandes, PJL

    1996-12-01

    Full Text Available compounds between the solid and liquid metals. To study the embrittlement of two brass alloys by molten gallium (Tm = 29.8 °C), Tensile tests on smooth, unnotched specimens were used. The alloys used were CZ106, a 70/30 alpha-brass, and CZ109, a 60/40 alpha...

  12. Advanced Materials and Manufacturing for Low-Cost, High-Performance Liquid Rocket Combustion Chambers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Silicided niobium alloy (C103) combustion chambers have been used extensively in both NASA and DoD liquid rocket propulsion systems. Niobium alloys offer a good...

  13. Liquids and liquid mixtures

    CERN Document Server

    Rowlinson, J S; Baldwin, J E; Buckingham, A D; Danishefsky, S

    2013-01-01

    Liquids and Liquid Mixtures, Third Edition explores the equilibrium properties of liquids and liquid mixtures and relates them to the properties of the constituent molecules using the methods of statistical thermodynamics. Topics covered include the critical state, fluid mixtures at high pressures, and the statistical thermodynamics of fluids and mixtures. This book consists of eight chapters and begins with an overview of the liquid state and the thermodynamic properties of liquids and liquid mixtures, including vapor pressure and heat capacities. The discussion then turns to the thermodynami

  14. The effect of the magnetic field on the viscosity of the liquid alloys%磁场对液态金属粘度的影响

    Institute of Scientific and Technical Information of China (English)

    徐星

    2015-01-01

    金属熔体的粘滞性是液态金属原子迁徙能力的一种表现,反映了原子间结合能力的大小。理论研究表明:在无磁场的条件下,随着温度的降低金属熔体的粘度增大;在磁场的条件下,金属熔体的粘度随着磁场强度的增加而增大。磁场对粘度的影响是洛伦兹力和磁化能的共同作用的结果。%The viscosity of liquid metal is a migratory ability of atoms, which reflects the size of binding force between atoms.The experimental results howedthat:the iscosity of etalin creasesas the temperaturede creases in the absence of amagneticfield.Under the condition of the magnetic field,the viscosity is increased with he decreasing in tensity of the magnetic ield.Theeffect of the magnetic fieldon the viscosityis Lorentz for ceandmagneticen-ergytheresult of jointaction.

  15. Surface exploration of a room-temperature ionic liquid-chitin composite film decorated with electrochemically deposited PdFeNi trimetallic alloy nanoparticles by pattern recognition: an elegant approach to developing a novel biotin biosensor.

    Science.gov (United States)

    Gholivand, Mohammad-Bagher; Jalalvand, Ali R; Goicoechea, Hector C; Paimard, Giti; Skov, Thomas

    2015-01-01

    In this study, a novel biosensing system for the determination of biotin (BTN) based on electrodeposition of palladium-iron-nickel (PdFeNi) trimetallic alloy nanoparticles (NPs) onto a glassy carbon electrode (GCE) modified with a room-temperature ionic liquid (RTIL)-chitin (Ch) composite film (PdFeNi/ChRTIL/GCE) is established. NPs have a wide range of applications in science and technology and their sizes are often measured using transmission electron microscopy (TEM) or X-ray diffraction. Here, we used a pattern recognition method (digital image processing, DIP) for measuring particle size distributions (PSDs) from scanning electron microscopic (SEM) images in the presence of an uneven background. Different depositions were performed by varying the number of cyclic potential scans (N) during electroreduction step. It was observed that the physicochemical properties of the deposits were correlated to the performance of the PdFeNi/ChRTIL/GCE with respect to BTN assay. The best results were obtained for eight electrodeposition cyclic scans, where small-sized particles (19.54 ± 6.27 nm) with high density (682 particles µm(-2)) were obtained. Under optimized conditions, a linear range from 2.0 to 44.0 × 10(-9) mol L(-1) and a limit of detection (LOD) of 0.6 × 10(-9) mol L(-1) were obtained. The PdFeNi/ChRTIL nanocomposite showed excellent compatibility, enhanced electron transfer kinetics, large electroactive surface area, and was highly sensitive, selective, and stable toward BTN determination. Finally, the PdFeNi/ChRTIL/GCE was satisfactorily applied to the determination of BTN in infant milk powder, liver, and egg yolk samples.

  16. Nanoparticle enhanced ionic liquid heat transfer fluids

    Science.gov (United States)

    Fox, Elise B.; Visser, Ann E.; Bridges, Nicholas J.; Gray, Joshua R.; Garcia-Diaz, Brenda L.

    2014-08-12

    A heat transfer fluid created from nanoparticles that are dispersed into an ionic liquid is provided. Small volumes of nanoparticles are created from e.g., metals or metal oxides and/or alloys of such materials are dispersed into ionic liquids to create a heat transfer fluid. The nanoparticles can be dispersed directly into the ionic liquid during nanoparticle formation or the nanoparticles can be formed and then, in a subsequent step, dispersed into the ionic liquid using e.g., agitation.

  17. 液态三元Fe-Sn-Si/Ge偏晶合金相分离过程的实验和模拟研究∗%Exp erimental investigation and numerical simulation on liquid phase separation of ternary Fe-Sn-Si/Ge monotectic alloy

    Institute of Scientific and Technical Information of China (English)

    吴宇昊; 王伟丽; 魏炳波

    2016-01-01

    The liquid phase separation of small Fe-Sn-Si/Ge alloy droplets under reduced-gravity condition is investigated experimentally by free fall technique and theoretically by lattice Boltzmann method. In the drop tube experiments, the Fe-Sn-Si/Ge monotectic alloys are heated by induction heating in an ultrahigh vacuum chamber and further overheated to 200 K above their liquid temperatures for a few seconds. Finally, the molten alloy melt is ejected out from the small orifice of a quartz tube by high pressure jetting gas of He and dispersed into numerous tiny droplets, which are rapidly solidified during free fall in a protecting He gas environment. These droplets benefit from the combined advantages of high undercooling, containerless state and rapid cooling, which can provide an effcient way to study the liquid phase separation of high-temperature alloys in microgravity. In order to effciently reproduce the dynamic process of phase separation inside drop tube equipment, the effects of surface segregation and Marangoni convection are introduced into the interaction potential of different liquids within lattice Boltzmann theory. Based on this modified model, the dynamic mechanism of phase separation can be suffciently analyzed and the phase separation patterns can be realistically simulated. Experimental results demonstrate that conspicuous liquid phase separations have taken place for both Fe-Sn-Si and Fe-Sn-Ge alloy droplets and the corresponding morphologies are mainly characterized by core-shell and dispersed structures. The phase separation process can be modulated by the third-element addition. As the Si element of Fe-Sn-Si alloy is replaced by the Ge element with the same fraction, the distribution order of Fe-rich and Sn-rich zones is reversed within core-shell structure. A core-shell structure composed of a Fe-rich core and a Sn-rich shell is frequently observed in Fe-Sn-Si alloy droplets whereas the Fe-Sn-Ge alloy droplets tend to form a core-shell structure

  18. Free energy change of off-eutectic binary alloys on solidification

    Science.gov (United States)

    Ohsaka, K.; Trinh, E. H.; Lin, J.-C.; Perepezko, J. H.

    1991-01-01

    A formula for the free energy difference between the undercooled liquid phase and the stable solid phase is derived for off-eutectic binary alloys in which the equilibrium solid/liquid transition takes place over a certain temperature range. The free energy change is then evaluated numerically for a Bi-25 at. pct Cd alloy modeled as a sub-subregular solution.

  19. Intermetallic particles-induced pitting corrosion in 6061-T651 aluminium alloy

    CSIR Research Space (South Africa)

    Mutombo, K

    2011-07-01

    Full Text Available -Induced Pitting Corrosion in 6061-T651 Aluminium Alloy Kalenda Mutombo Council for Scientific and Industrial Research (CSIR), South Africa kmutombo@csir.co.za Keywords: pitting corrosion, 6061-T651 aluminium alloy, intermetallic particles, 3.5% Na... extrudability, reasonable weldability and good corrosion resistance. This alloy finds widespread application in ship building and in the fabrication of tank containers for transporting various liquids. 6061-T651 aluminium alloy is, however, prone to pitting...

  20. Corrosion behavior of construction materials for ionic liquid hydrogen compressor

    DEFF Research Database (Denmark)

    Arjomand Kermani, Nasrin; Petrushina, Irina; Nikiforov, Aleksey Valerievich

    2016-01-01

    The corrosion behavior of various commercially available stainless steels and nickel-based alloys as possible construction materials for components which are in direct contact with one of five different ionic liquids was evaluated. The ionic liquids, namely: 1-ethyl-3-methylimidazolium triflate, 1...... liquid hydrogen compressor. An electrochemical cell was specially designed, and steady-state cyclic voltammetry was used to measure the corrosion resistance of the alloys in the ionic liquids at 23 °C, under atmospheric pressure. The results showed a very high corrosion resistance and high stability...... for all the alloys tested. The two stainless steels, AISI 316L and AISI 347 showed higher corrosion resistance compared to AISI 321 in all the ionic liquids tested. It was observed that small addition of molybdenum, tantalum, and niobium to the alloys increased the corrosion stability in the ionic liquids...

  1. Precipitation hardening and hydrogen embrittlement of aluminum alloy AA7020

    Indian Academy of Sciences (India)

    Santosh Kumar; T K G Namboodhiri

    2011-04-01

    AA7020 Al–Mg–Zn, a medium strength aluminium alloy, is used in welded structures in military and aerospace applications. As it may be subjected to extremes of environmental exposures, including high pressure liquid hydrogen, it could suffer hydrogen embrittlement. Hydrogen susceptibility of alloy AA7020 was evaluated by slow strain-rate tensile testing, and delayed failure testing of hydrogen-charged specimens of air-cooled, duplexaged, and water-quenched duplex agedmaterials. The resistance to hydrogen embrittlement of the alloy was found to be in the order of air-cooled duplex aged alloy > as-received (T6 condition) > water quenched duplex aged material.

  2. Characteristics and experimental evaluation of super-heat-resisting Nb-based and Mo-based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Morinaga, Masahiko; Furui, Mitsuaki; Noda, Kenji; Oda, Masaaki [Nagoya Univ. (Japan). School of Engineering

    1997-03-01

    Nb-based and Mo-based alloys have been investigated in order to develop the frontiers of materials technique which will be utilized in the environment of high-temperature liquid alkali metals. In this study, both mechanical properties and corrosion resistance to liquid Li were evaluated for two designed Mo-based alloys, Mo-15Re-0.1Zr and Mo-15Re-0.1Zr-0.1Ti. In addition, a series of corrosion test was performed with provisionally designed Nb-based alloys, Nb-(1-4)Hf. High-temperature tensile properties: The designed Mo-based alloys were found to have more excellent high-temperature tensile properties, compared to the commercial TZM alloy. High-temperature creep properties: The designed Mo-based alloys were superior in the high-temperature creep properties to other solid solution hardening Mo-based alloys. Workability: The designed Mo-based alloys exhibited an excellent workability, irrespective of the Ti addition. Corrosion resistance to liquid Li: The Nb-1Hf alloy was chosen as a promising alloy of having the highest corrosion resistance among the Nb-based alloys. Also, the Mo-15Re-0.1Zr-0.1Ti alloy was superior to Mo-15Re-0.1Zr alloy, in view of the corrosion resistance to liquid Li. (J.P.N.)

  3. Additional force field in cooling process of cellular Al alloy

    Institute of Scientific and Technical Information of China (English)

    郑明军; 何德坪; 戴戈

    2002-01-01

    The foaming process of Al alloy is similar to that of Al, but there is a solid-liquid state zone in the solidification process of cellular Al alloy which does not exist in the case of Al. In the unidirectional solidification of cellular Al alloy, the proportion of the solid phase gradually reduces from the solid front to the liquid front. This will introduce a force and result in a serious quick shrinkage. By the mathematic and physical mode, the solidification of the cellular Al alloy is studied. The data measured by experiment are close to the result calculated by the mode. This kind of shrinkage can be solved by suitable cooling method in appropriate growth stage. The compressive strength of the cellular Al alloy made by this way is 40% higher than that of cellular Al.

  4. 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.

  5. Real-time monitoring of plutonium content in uranium-plutonium alloys

    Science.gov (United States)

    Li, Shelly Xiaowei; Westphal, Brian Robert; Herrmann, Steven Douglas

    2015-09-01

    A method and device for the real-time, in-situ monitoring of Plutonium content in U--Pu Alloys comprising providing a crucible. The crucible has an interior non-reactive to a metallic U--Pu alloy within said interior of said crucible. The U--Pu alloy comprises metallic uranium and plutonium. The U--Pu alloy is heated to a liquid in an inert or reducing atmosphere. The heated U--Pu alloy is then cooled to a solid in an inert or reducing atmosphere. As the U--Pu alloy is cooled, the temperature of the U--Pu alloy is monitored. A solidification temperature signature is determined from the monitored temperature of the U--Pu alloy during the step of cooling. The amount of Uranium and the amount of Plutonium in the U--Pu alloy is then determined from the determined solidification temperature signature.

  6. Thermal aging effects in refractory metal alloys

    Science.gov (United States)

    Stephens, Joseph R.

    1987-01-01

    The alloys of niobium and tantalum are attractive from a strength and compatibility viewpoint for high operating temperatures required in materials for fuel cladding, liquid metal transfer, and heat pipe applications in space power systems that will supply from 100 kWe to multi-megawatts for advanced space systems. To meet the system requirements, operating temperatures ranging from 1100 to 1600 K have been proposed. Expected lives of these space power systems are from 7 to 10 yr. A program is conducted at NASA Lewis to determine the effects of long-term, high-temperature exposure on the microstructural stability of several commercial tantalum and niobium alloys. Variables studied in the investigation include alloy composition, pre-age annealing temperature, aging time, temperature, and environment (lithium or vacuum), welding, and hydrogen doping. Alloys are investigated by means of cryogenic bend tests and tensile tests. Results show that the combination of tungsten and hafnium or zirconium found in commercial alloys such as T-111 and Cb-752 can lead to aging embrittlement and increased susceptibility to hydrogen embrittlement of ternary and more complex alloys. Modification of alloy composition helps to eliminate the embrittlement problem.

  7. Solidification microstructure formation in HK40 and HH40 alloys

    Science.gov (United States)

    Ding, Xian-fei; Liu, Dong-fang; Guo, Pei-liang; Zheng, Yun-rong; Feng, Qiang

    2016-04-01

    The microstructure formation processes in HK40 and HH40 alloys were investigated through JmatPro calculations and quenching performed during directional solidification. The phase transition routes of HK40 and HH40 alloys were determined as L → L + γ → L + γ + M7C3 → γ + M7C3 → γ + M7C3 + M23C6→ γ + M23C6 and L → L + δ → L + δ + γ→ L + δ + γ + M23C6 δ + γ + M23C6, respectively. The solidification mode was determined to be the austenitic mode (A mode) in HK40 alloy and the ferritic-austenitic solidification mode (FA mode) in HH40 alloy. In HK40 alloy, eutectic carbides directly precipitate in a liquid and coarsen during cooling. The primary γ dendrites grow at the 60° angle to each other. On the other hand, in HH40 alloy, residual δ forms because of the incomplete transformation from δ to γ. Cr23C6 carbide is produced in solid delta ferrite δ but not directly in liquid HH40 alloy. Because of carbide formation in the solid phase and no rapid growth of the dendrite in a non-preferential direction, HH40 alloy is more resistant to cast defect formation than HK40 alloy.

  8. Effect of alloying addition and microstructural parameters on mechanical properties of 93% tungsten heavy alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ravi Kiran, U., E-mail: uravikiran@gmail.com [Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad 500 058 (India); Panchal, A.; Sankaranarayana, M. [Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad 500 058 (India); Nageswara Rao, G.V.S. [National Institute of Technology, Warangal 506004 (India); Nandy, T.K. [Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad 500 058 (India)

    2015-07-29

    Liquid phase sintering, heat treatment and swaging studies on three tungsten heavy alloys, 93W–4.9Ni–2.1Fe (wt%), 93W–4.2Ni–1.2Fe–1.6Co (wt%) and 93W–4.9Ni–1.9Fe–0.2Re (wt%) were carried out in detail with respect to microstructure, tensile and impact properties. All the alloys were sintered and swaged to 40% deformation. The results indicate that Re addition reduces the grain size of the alloy compared to W–Ni–Fe and W-Ni-Fe-Co alloys. W–Ni–Fe–Re alloy shows superior tensile properties in heat treated condition as compared to W–Ni–Fe and W–Ni–Fe–Co alloys. SEM study of fractured specimens clearly indicates that the failure in case of W–Ni–Fe–Re was due to transgranular cleavage of tungsten grains and W–W de-cohesion. W–Ni–Fe and W–Ni–Fe–Co alloys also failed by mixed mode failure. However, in these cases, ductile dimples corresponding the failure of the matrix phase was rarely seen. Thermo-mechanical processing resulted in significant changes in mechanical properties. While W–Ni–Fe–Re alloy showed the highest tensile strength (1380 MPa), W–Ni–Fe–Co exhibited the highest elongation (12%) to failure. A detailed analysis involving microstructure, mechanical properties and failure behavior was undertaken in order to understand the property trends.

  9. Advanced Materials and Manufacturing for Low-Cost, High-Performance Liquid Rocket Combustion Chambers, Phase II Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Silicided niobium alloy (C103) combustion chambers have been used extensively in both NASA and DoD liquid rocket propulsion systems. Niobium alloys offer a good...

  10. Medium-Range Order Structure and Fragility of Superheated Melts of Amorphous CuHf Alloys

    Institute of Scientific and Technical Information of China (English)

    BIAN Xiu-Fang; SUN Bao-An; HU Li-Na

    2006-01-01

    @@ The structural factors of amorphous CuHf alloys at different temperatures are determined by using a high temperature x-ray diffractometer. It is found that not only the short-range order structure but also the medium-range order structure exists in amorphous CuHf alloys. The dynamic viscosities of CuHf alloy melts are measured by a torsional oscillation viscometer. The fragility of superheated melts of CuHf alloys is calculated based on the viscosity data. The experimental results show that the glass-forming ability of the CuHf alloys is closely related to the fragility of their superheated melt. The relationship between the medium-range order structures and the fragility of superheated melts has also been established in amorphous CuHf alloys. In contrast to the fragility of supercooled liquids, the fragility of superheated liquids promises a better approach to reflecting the dynamics of glass forming liquids.

  11. Electroplated solder alloys for flip chip interconnections

    Science.gov (United States)

    Annala, P.; Kaitila, J.; Salonen, J.

    1997-01-01

    Flip chip mounting of bare dice is gaining widespread use in microelectronics packaging. The main drivers for this technology are high packaging density, improved performance at high frequency, low parasitic effects and potentially high reliability and low cost. Many companies have made significant efforts to develop a technology for bump processing, bare die testing and underfill encapsulation to gain the benefit of all potential advantages. We have focussed on low cost bumping of fully processed silicon wafers to develop a flexible scheme for various reflow requirements. The bumping process is based on galvanic plating from an alloy solution or, alternatively, from several elemental plating baths. Sputtered Mo/Cu or Cr/Cu is used as a wettable base for electroplating. Excess base metal is removed by using the bumps as an etching mask. Variation of the alloy composition or the layer structure, allows the adjustment of the bump reflow temperature for the specific requirements of the assembly. Using binary tin-lead and ternary tin-lead-bismuth alloys, reflow temperatures from 100 °C (bismuth rich alloys) to above 300 °C (lead rich alloys) can be covered. The influence of the plating current density on the final alloy composition has been established by ion beam analysis of the plated layers and a series of reflow experiments. To control the plating uniformity and the alloy composition, a new cup plating system has been built with a random flow pattern and continuous adjustment of the current density. A well-controlled reflow of the bumps has been achieved in hot glycerol up to the eutectic point of tin-lead alloys. For high temperature alloys, high molecular weight organic liquids have been used. A tensile pull strength of 20 g per bump and resistance of 5 mΩ per bump have been measured for typical eutectic tin-lead bumps of 100 μm in diameter.

  12. Diffusion bonding of Al7075 alloy to titanium aluminum vanadate alloy

    Science.gov (United States)

    Alhazaa, Abdulaziz Nasser

    The aluminum alloy (Al7075) and titanium alloy (Ti-6Al-4V) are used in a variety of applications in the aerospace industry. However, the high cost of Ti-6Al-4V alloy has been a major factor which has limited its use and therefore, the ability to join Al7075 alloy to Ti-6Al-4V alloy can provide a product that is less costly, but retains the high strength and light weight properties necessary for the transport industry. However, the large difference in the physical properties between these two alloys prevents the use of conventional joining techniques such as fusion welding to join these dissimilar alloys. Therefore, the diffusion bonding technique was used to join Al7075 alloy to Ti-6Al-4V alloy with the objective of minimizing microstructural changes of the two alloys during the bonding process. In this thesis, solid state and liquid phase bonding processes were undertaken. Solid state bonding was employed without interlayers and was successful at 510°C and 7 MPa. The bond interface showed an absence of the oxides due to the dissolution of oxygen into the titanium solution. Bonds made using copper interlayers at a temperature sufficient enough to form eutectic liquid formation between copper and aluminum were produced. The intermetallics theta(Al2Cu), S(Al2CuMg) and T(Al2Mg3Zn3) were identified at the aluminum interface while Cu3Ti2 intermetallic was identified at the titanium interface. Bonds made using tin based alloys interlayers and copper coatings were successful and gave the highest shear strength. The eutectic formation on the Al7075 alloy was responsible for joint formation at the aluminum interface while the formation of Sn3Ti5 intermetallic was responsible for the joint formation at titanium interface. The corrosion rate of the bonds decreased with increasing bonding time for joints made using the tin based interlayer in 3% NaCl solution. However, the presence of copper within the joint increased the corrosion rate of the bonds and this was attributed to

  13. Mechanism of constitution liquid film migration

    Energy Technology Data Exchange (ETDEWEB)

    Zuo, Hongjun [Univ. of Alabama, Birmingham, AL (United States)

    1999-06-01

    Liquid film migration (LFM) in liquid phase sintering classically involves a large metastable liquid volume adjacent to solid, and migration occurs at an isolated solid-liquid (S-L) interface. Constitutional liquid film migration (CLFM), discovered in alloy 718, has major characteristics similar to those of LFM, except that the metastable liquid is from the constitutional liquation of precipitates on the grain boundary. The similarity between LFM and CLFM has led to the theory that coherency lattice strain responsible for LFM is also responsible for CLFM. The coherency strain hypothesis was tested in this study by evaluating whether the Hillert model of LFM would also apply for CLFM. Experimental results of CLFM in alloy 718 showed that migration velocity followed the trend predicted by the Hillert model. This indicates that the coherency strain hypothesis of LFM also applies for CLFM and that the coherency lattice strain responsible for LFM is also the driving force for CLFM.

  14. Order and disorder in liquid alloys.

    NARCIS (Netherlands)

    Alblas, Bernard Pieter

    1983-01-01

    In the theory of mixtures the concept of ideal mixtures, though naive and simple, is an important one. It defines the borderline betvreen at the oneh and,t he mixturesw ith a tenden cyto clusterin or phases eparation and at the other hand, the mixtures with a tendency to compound formation. The form

  15. Structure and phase transformations in Fe-Ni-Mn alloys nanostructured by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Pustov, L.Yu., E-mail: pustov@mail.r [Moscow State Institute of Steel and Alloys, Leninsky prosp. 4, Moscow 119049 (Russian Federation); Tcherdyntsev, V.V.; Abdulhalikov, Sh.M.; Kaloshkin, S.D.; Shelekhov, E.V. [Moscow State Institute of Steel and Alloys, Leninsky prosp. 4, Moscow 119049 (Russian Federation); Estrin, E.I. [Central Research Inst. of Ferrous Metallurgy, 2nd Baumanskaya st, 9/23, Moscow 107005 (Russian Federation); Baldokhin, Yu.V. [Institute of Chemical Physics, Russian Academy of Sciences, Kosygina str., 4, Moscow 117334 (Russian Federation)

    2009-08-26

    Ternary Fe{sub 86}Ni{sub x}Mn{sub 14-x} alloys, where x = 0, 2, 4, 6, 8, 10, 12, 14, 16 at.%, were prepared by the mechanical alloying (MA) of elemental powders in a high-energy planetary ball mill. X-ray diffraction analysis and Moessbauer spectroscopy were used to investigate the structure and phase composition of samples. Thermo-magnetic measurements were used to study the phase transformation temperatures. The MA results in the formation of bcc alpha-Fe and fcc gamma-Fe based solid solutions, the hcp phase was not observed after MA. As-milled alloys were annealed with further cooling to ambient or liquid nitrogen temperatures. A significant decrease in martensitic points for the MA alloys was observed that was attributed to the nanocrystalline structure formation.

  16. Interface properties and phase formation between surface coated SKD61 and aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    Se-Weon CHOI; Young-Chan KIM; Se-Hun CHANG; Ik-Hyun OH; Joon-Sik PARK; Chang-Seog KANG

    2009-01-01

    The intermediate phase formation and surface protection effects between SKD61 die mold alloys and aluminum alloys were investigated during a simulated die-casting process. The surface coatings of SKD61 alloy were carried out via Si pack cementation coatings at 900 ℃ for 10 h and the e-FeSi phase formed. When the coated SKD61 alloy was dipped in the liquid aluminum alloy (ALDC12), the surface coated SKD61 alloys showed better surface properties compared with uncoated SKD61 alloys, i.e., the intermediate phases (FeSiAl compound) were not produced for the coated SKD61 alloy. The coating layer of e-FeSi served as a diffusion barrier for the formation of FeSiAl compounds.

  17. Translating VDM to Alloy

    DEFF Research Database (Denmark)

    Lausdahl, Kenneth

    2013-01-01

    . Traditionally, theorem provers are used to prove that specifications are correct but this process is highly dependent on expert users. Alternatively, model finding has proved to be useful for validation of specifications. The Alloy Analyzer is an automated model finder for checking and visualising Alloy...... 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...

  18. Structural relaxation in viscous metallic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, A. [National Inst. of Standards and Technology (BFRL), Gaithersburg, MD (United States)]|[Technische Univ. Muenchen, Muenchen (Germany); Wuttke, J.; Petry, W. [Technische Univ. Muenchen, Muenchen (Germany); Schober, H. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France); Randl, O.G. [Manufacture Michelin, Clermont-Ferrand (France)

    1999-11-01

    Recently, metallic alloys have been found that exhibit extremely large viscosities in the liquid state. These liquids can be quenched into bulk metallic glasses at relatively modest cooling rates. In contrast to simple metals the structural relaxation of these systems show a two step decay in the liquid state. This behaviour has long been known for molecular or ionic glass formers in their under-cooled liquid state. Applying an analysis previously used for the glass formers (mode-coupling theory) a full quantitative description of the neutron data is obtained for these metallic liquids. (authors) 3 refs., 2 figs.

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

    Institute of Scientific and Technical Information of China (English)

    FANG Liang; XIAO Feng; TAO Zainan; MuKai Kusuhiro

    2005-01-01

    The density of molten Ni-W alloys was measured with a modified pycnometric method. It is found that the density of the molten Ni- W alloys decreases with temperature rising, but increases with the increase of tungsten concentration in the alloys. The molar volume of molten Ni- W binary alloys increases with the increase of temperature and tungsten concentration. The partial molar volume of tungsten in liquid Ni- W binary alloy has been calculated approximately as ( - 1.59+ 5.64 × 10-3 T) × 10-6m3 ·mol-1.

  20. Microstructures of Sintered Mo-Cu Alloys with Mechanically Activated Powder

    Institute of Scientific and Technical Information of China (English)

    蒋凯; 张秀英; 郭崇峰

    2001-01-01

    Mechanical activation and liquid phase sintering were used to manufacture high performance Mo-Cu alloy and develop new processes. The microstructures and properties of the alloy were investigated. The experimental results showed that: (1) the ball milled Mo/Cu powder has lamellar structure, (2) the microstructures of the sintered Mo-Cu alloy were homogenous compound structures of adhesive phase Cu linking Mo grains, (3) Mo grains frequently strung or ga thered in Cu phase, and (4) the full densities of Mo-Cu alloy was achieved through sintering and special densification process. As a result, the properties of the alloy are good enough to satisfy various requirements.

  1. Thermophysical Property Measurements of Silicon-Transition Metal Alloys

    Science.gov (United States)

    Banish, R. Michael; Erwin, William R.; Sansoucie, Michael P.; Lee, Jonghyun; Gave, Matthew A.

    2014-01-01

    Metals and metallic alloys often have high melting temperatures and highly reactive liquids. Processing reactive liquids in containers can result in significant contamination and limited undercooling. This is particularly true for molten silicon and it alloys. Silicon is commonly termed "the universal solvent". The viscosity, surface tension, and density of several silicon-transition metal alloys were determined using the Electrostatic Levitator system at the Marshall Space Flight Center. The temperature dependence of the viscosity followed an Arrhenius dependence, and the surface tension followed a linear temperature dependence. The density of the melts, including the undercooled region, showed a linear behavior as well. Viscosity and surface tension values were obtain for several of the alloys in the undercooled region.

  2. [Radioactivity of phosphorus implanted TiNi alloy].

    Science.gov (United States)

    Zhao, Xingke; Cai, Wei; Zhao, Liancheng

    2003-09-01

    Exposed to neutron flow, the phosphorus implanted TiNi alloy gets radioactive. This radioactive material is used in vascular stent for prevention and cure of restenosis. Phosphorus implantation is carried out in a plasma immerged ion implantation system, and the dose of phosphorus implantation is in the range of 2-10 x 10(17) cm-2. After ion implantation, the alloy is exposed to the slow neutron flow in a nuclear reactor, the dose of the slow neutron is 1.39-5.88 x 10(19) n/cm2. The radioactivity of the TiNi alloy was measured by liquid scintillation spectrometry and radio-chromic-film dosimetry. The result shows that whether the phosphorus is implanted or not, the TiNi alloy comes to be radioactive after exposure to neutron flow. Just after neutron irradiation, the radiation dose of phosphorus implanted TiNi alloy is about one hundred times higher than that of un-phosphorus implanted TiNi alloy. The radiation difference between phosphorus and un-phosphorus implanted alloy decreases as time elapses. Within three months after neutron irradiation, the average half-decay period of phosphorus implanted TiNi alloy is about 62 days. The radiation ray penetration of phosphorus implanted TiNi alloy is deeper than that of pure 32P; this is of benefit to making radiation uniformity between stent struts and reducing radiation grads beyond the edge of stent.

  3. 从2AlCl3/Et3NHCl离子液体中电沉积制备Ni和Ni-Al合金%Preparation of Ni and Ni-Al Alloys from 2AlCl3/Et3NHCl Ionic Liquid by Electrodeposition

    Institute of Scientific and Technical Information of China (English)

    高丽霞; 王丽娜; 齐涛; 余江

    2012-01-01

    在含Ni2+的2AlCl3/Et3NHCl离子液体中的铜电极上通过恒电位电沉积制备出金属Ni和Ni-Al合金.采用循环伏安和计时电流方法,揭示铜电极上沉积金属Ni的成核机理,研究了电沉积Ni-Al合金的机理,以及恒电位沉积Ni-Al合金工艺条件对沉积Ni-Al合金表面形貌和电流效率的影响.结果表明:在铜电极上电沉积金属Ni的成核机理为受扩散控制的三维瞬时成核过程.在电量≥3.0 C时,电沉积Ni-Al合金的组成基本不再变化.Ni-Al合金的电沉积机理为,Ni的电沉积受扩散控制,同时进行Al的欠电位沉积,在Ni-Al合金电沉积过程中某些Ni-Al合金相的沉积可能受动力学限制而使Ni-Al合金的组成偏离热力学预测结果.在电沉积Ni-Al合金的沉积电流小且平稳,电沉积速率慢条件下,Ni-Al合金表面形貌致密均一,反之就会出现瘤节.电沉积Ni-Al合金的电流效率>90%.电沉积物的组成接近于Ni3Al合金.%Nickel and nickel-aluminum alloy were successfully electrodeposited on Cu electrodes from 2: 1 molar ratio aluminum chloride (AICI3)/triethylamine hydrochloride (Et3NHCI) ionic liquids containing Ni2* by constant potential electrolysis. The nucleation mechanism of nickel electrodeposition on Cu was investigated by cyclic voltammograms and chronoamperometry. The mechanism and the influence of experimental conditions on the current efficiency and the surface morphology of nickel-aluminum alloy electrodeposition on Cu electrodes were studied. The electrodeposition of nickel on Cu electrodes was controlled by three-dimensional instantaneous nucleation with diffusion-controlled growth. The Ni-AI alloy composition did not become independent of the deposition charge until at least 3.0 C had been accumulated. The mechanism of Ni-AI alloy formation appears to involve the underpotential deposition of aluminum on the developing nickel deposit and alloy formation must be kinetically hindered because the aluminum

  4. 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...

  5. Turbine Blade Alloy

    Science.gov (United States)

    MacKay, Rebecca

    2001-01-01

    The High Speed Research Airfoil Alloy Program developed a fourth-generation alloy with up to an +85 F increase in creep rupture capability over current production airfoil alloys. Since improved strength is typically obtained when the limits of microstructural stability are exceeded slightly, it is not surprising that this alloy has a tendency to exhibit microstructural instabilities after high temperature exposures. This presentation will discuss recent results obtained on coated fourth-generation alloys for subsonic turbine blade applications under the NASA Ultra-Efficient Engine Technology (UEET) Program. Progress made in reducing microstructural instabilities in these alloys will be presented. In addition, plans will be presented for advanced alloy development and for computational modeling, which will aid future alloy development efforts.

  6. EFFECT OF PRE-ALLOYING CONDITION ON THE BULK AMORPHOUS ALLOY ND(60)FE(30)AL(10).

    Energy Technology Data Exchange (ETDEWEB)

    OCONNOR,A.S.; LEWIS,L.H.; MCCALLUM,R.W.; DENNIS,K.W.; KRAMER,M.J.; KIM ANH,D.T.; DAN,N.H.; PHUC,N.X.

    2000-09-10

    Bulk metallic glasses are materials that require only modest cooling rates to obtain amorphous solids directly from the melt. Nd{sub 60}Fe{sub 30}Al{sub 10} has been reported to be a ferromagnetic bulk metallic glass that exhibits high coercivity, a combination unlike conventional Nd-based amorphous magnetic alloys. To clarify the relationship between short-range order and high coercivity in glassy Nd{sub 60}Fe{sub 30}Al{sub 10}, experiments were performed to verify the existence of a homogeneous liquid state prior to rapid solidification. Alloys were prepared by various pre-alloying routes and then melt-spun. Arc-melted alloys were prepared for melt spinning using three different protocols involving: (1) alloying all three elements at once, (2) forming a Nd-Fe alloy which was subsequently alloyed with Al, and (3) forming a Fe-Al alloy for subsequent alloying with Nd. XRD, DTA, and magnetic measurement data from the resultant ribbons indicate significant differences in both the glassy fraction and the crystalline phase present in the as-spun material. These observed differences are attributed to the presence of highly stable nanoscopic aluminide-and/or silicide-phases, or motes, present in the melt prior to solidification. These motes would affect the short-range order and coercivity of the resultant glassy state and are anticipated to provide heterogeneous nucleation sites for crystallization.

  7. TEM microstructure of mechanically alloyed Ti-12Mg powders

    Institute of Scientific and Technical Information of China (English)

    T. S. KIM; B. T. LEE; J. P. AHN; J. K. PARK; J. C. BAE

    2006-01-01

    The microstructures of mechanical alloyed(MA) Ti-12%Mg alloy powders were examined using a high resolution TEM (HRTEM). The effect of MA atmospheres such as argon gas and liquid isopropyl alcohol on the resultant microstructure was investigated. Both the MA powders form a homogeneous Ti-Mg solid solution, but the oxidation behavior is distinguished. The phase change was studied as a function of milling conditions and annealing temperatures.

  8. Effects of alloying elements on nitrogen diffusion behavior around TiN/Ti interface α region in as-cast titanium alloys

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    To characterize the effects of alloying elements on inclusion dissolution of titanium nitride, the content profiles of elements around TiN/Ti boundary α phase regions in liquid titanium alloys have been experimentally carried out. Four kinds of commercial alloys of CpTi, Ti64, Ti17 and Ti6242 containing different α-stabilizing or β-stabilizing elements are examined through artificially embedding the TiN sponge particle into liquid alloys in VAR conditions. The content profiles of nitrogen and alloying elements around TiN/Ti boundary were measured by WDX and microprobe for as-cast samples. The content profiles of nitrogen and alloying elements around N-containing solid in αTi region of these alloys show a common features of a steep change. In particular, the content profiles of elements for Ti6242 demonstrate unique change of a more gentle change tendency and further deeper into the alloy matrix. The experiment results show that, the differences among composite effects of alloying elements in different alloys within nitrogen-induced diffusion α region result in different dissolution and diffusion behaviors to overcome the α phase region barriers.

  9. Structure and properties of stir-cast zinc alloys

    Energy Technology Data Exchange (ETDEWEB)

    LeHuy, H.; Blain J.; Masounave, J.; Bata, G.L. (Industrial Materials Research Institute, Boucherville, P.Q. (Canada))

    Stir casting (or rheocasting) of ZA-27 zinc alloys was investigated experimentally. By vigorously agitating the alloys during cooling, the dendrites that were forming were fragmented giving a unique structure composed of spherical and rosette shaped particles suspended in the remaining liquid. Under high shear rates ({center dot}{gamma} = 300s{sup {minus}1} or more) the slurries with primary particle concentrations as high as 60% displayed viscosities as low as 20 poises and could easily be casted. The effects of processing variables such as shearing and cooling rates and casting temperatures were studied. Their relative importance on the rheological and microstructural behavior of the stir cast alloys are discussed. Results from viscosity measurements on slurries show that non-dendritical ZA-27 alloys obey a power law fluid model. Finally, results from mechanical and compressive studies carried out on solidified slurries are discussed and compared to conventional casted and wrought alloy properties.

  10. Rheological behaviour of semi-solid succinonitrile-camphor alloy

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Rheology experiments were carried out on succinonitrile-4% (mass fraction) camphor alloy, using a Haake VT550 viscometer.The results showed that the steady state viscosity of succinonitrile-4% camphor alloy in semi-solid process can be described well by the classical power law of viscosity versus shear rate, η= kym, and the test method can be used to simulate the semi-solid processing for metals. The viscosity of the organic alloy decreases with increasing shear rate at a given temperature within liquid-solid range, and the viscosity of the organic alloy slurries increases with decreasing temperature, decreases with decreasing cooling rate. The structure and viscosity of organic alloy during solidification are strongly influenced by shear rate.

  11. 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...

  12. Mechanics and forming theory of liquid metal forging

    Institute of Scientific and Technical Information of China (English)

    罗守靖; 姜巨福; 王迎; 藤东东

    2003-01-01

    On the basis of steel liquid forging and aluminium alloy liquid forging, liquid metal forging was investigated, such as the assembly model, metal plastic flowing, the force-displacement curves, the harmonious equation, calculation of value of altitude deformation and determination of specific pressure of liquid metal forging. On the basis of the theory of metal plastic forming and the characteristics of liquid metal forging, the achievements on the mechanics and forming theory of liquid metal forging were given out by combining the theory and experiments systematically, and an important preparation for establishing liquid metal forging theory was suggested.

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

    Science.gov (United States)

    Coffinberry, A.S.

    1959-08-25

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

  14. Simulation study for atomic size and alloying effects during forming processes of amorphous alloys

    Institute of Scientific and Technical Information of China (English)

    ZHENG Caixing; LIU Rangsu; PENG Ping; ZHOU Qunyi

    2004-01-01

    A molecular dynamics (MD) simulation study has been performed for the solidification processes of two binary liquid alloys Ag6Cu4 and CuNi by adopting the quantum Sutton-Chen many-body potentials. By analyzing bond-types, it is demonstrated that at the cooling rate of 2×1012K/s, the CuNi forms fcc crystal structures, while the Ag6Cu4 forms amorphous structures. The original reason is that the atomic radius ratio (1.13) of the CuAg is bigger than that (1.025) of the CuNi. This shows that the atomic size difference is indeed the main factor for forming amorphous alloys. Moreover, for Ag60Cu40,corresponding to the deep eutectic point in the phase diagram, it forms amorphous structure easily. This confirms that as to the forming tendency and stability of amorphous alloys, the alloying effect plays a key role. In addition, having analyzed the transformation of microstructures by using the bond-type index and cluster-type index methods, not only the key role of the icosahedral configuration to the formation and stability of amorphous alloys can be explained, but also the solidification processes of liquid metals and the characteristics of amorphous structures can be further understood.

  15. High strength alloys

    Science.gov (United States)

    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.

  16. 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.

  17. 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.)

  18. Creep Resistant Zinc Alloy

    Energy Technology Data Exchange (ETDEWEB)

    Frank E. Goodwin

    2002-12-31

    This report covers the development of Hot Chamber Die Castable Zinc Alloys with High Creep Strengths. This project commenced in 2000, with the primary objective of developing a hot chamber zinc die-casting alloy, capable of satisfactory service at 140 C. The core objectives of the development program were to: (1) fill in missing alloy data areas and develop a more complete empirical model of the influence of alloy composition on creep strength and other selected properties, and (2) based on the results from this model, examine promising alloy composition areas, for further development and for meeting the property combination targets, with the view to designing an optimized alloy composition. The target properties identified by ILZRO for an improved creep resistant zinc die-casting alloy were identified as follows: (1) temperature capability of 1470 C; (2) creep stress of 31 MPa (4500 psi); (3) exposure time of 1000 hours; and (4) maximum creep elongation under these conditions of 1%. The project was broadly divided into three tasks: (1) Task 1--General and Modeling, covering Experimental design of a first batch of alloys, alloy preparation and characterization. (2) Task 2--Refinement and Optimization, covering Experimental design of a second batch of alloys. (3) Task 3--Creep Testing and Technology transfer, covering the finalization of testing and the transfer of technology to the Zinc industry should have at least one improved alloy result from this work.

  19. Creep Resistant Zinc Alloy

    Energy Technology Data Exchange (ETDEWEB)

    Frank E. Goodwin

    2002-12-31

    This report covers the development of Hot Chamber Die Castable Zinc Alloys with High Creep Strengths. This project commenced in 2000, with the primary objective of developing a hot chamber zinc die-casting alloy, capable of satisfactory service at 140 C. The core objectives of the development program were to: (1) fill in missing alloy data areas and develop a more complete empirical model of the influence of alloy composition on creep strength and other selected properties, and (2) based on the results from this model, examine promising alloy composition areas, for further development and for meeting the property combination targets, with the view to designing an optimized alloy composition. The target properties identified by ILZRO for an improved creep resistant zinc die-casting alloy were identified as follows: (1) temperature capability of 1470 C; (2) creep stress of 31 MPa (4500 psi); (3) exposure time of 1000 hours; and (4) maximum creep elongation under these conditions of 1%. The project was broadly divided into three tasks: (1) Task 1--General and Modeling, covering Experimental design of a first batch of alloys, alloy preparation and characterization. (2) Task 2--Refinement and Optimization, covering Experimental design of a second batch of alloys. (3) Task 3--Creep Testing and Technology transfer, covering the finalization of testing and the transfer of technology to the Zinc industry should have at least one improved alloy result from this work.

  20. Novel Directional Solidification of Hypermonotectic Alloys

    Science.gov (United States)

    Grugel, R. N.; Fedoseyev, A. I.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    There are many metal alloy systems that separate into two different liquids upon cooling from a higher temperature. Uniform microstructural development during solidification of these immiscible liquids on Earth is hampered by inherent density differences between the phases. Microgravity processing minimizes settling but segregation still occurs due to gravity independent wetting and coalescence phenomena. Experiments with the transparent organic, metal analogue, succinonitrile-glycerol system were conducted in conjunction with applied ultrasonic energy. The processing parameters associated with this technique have been evaluated in view of optimizing dispersion uniformity. Characterization of the experimental results in terms of an initial modeling effort will also be presented.

  1. Compatibility of Anti-Wear Additives with Non-Ferrous Engine Bearing Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Jun [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Zhou, Yan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-01-01

    Investigate the compatibility of engine lubricant antiwear (AW) additives, specifically conventional zinc dialkyldithiophosphate (ZDDP) and newly developed ionic liquids (ILs), with selected non-ferrous engine bearing alloys, specifically aluminum and bronze alloys that are commonly used in connecting rod end journal bearings and bushings, to gain fundamental understanding to guide future development of engine lubricants

  2. Effect of Applied Pressure on the Joining of Combustion Synthesized Ni3Al Intermetallics with Al Alloy

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    We focused on the surface reinforcement of ligth weight casting alloys with Ni-Al intermetallic compounds by in-situ combustion reaction to improve the surface properties of non-ferrous casting components. In our previous works, green compact of elemental Ni and Al powders were reacted to form Ni3Al intermetallic compound by SHS (Self-propagating high temperature synthesis) reaction with the heat of molten Al alloy and simultaneously bonded with Al casting alloy. But some defects such as tiny cracks and porosities were remained in the reacted compact. So we applied pressure to prevent thermal cracks and fill up the pores with liquid Al alloy by squeeze casting process. The compressed Al alloy bonded with the Ni3Al intermetallic compound was sectioned and observed by optical microscopy and scanning electron microscopy (SEM). The stoichiometric compositions of the intermetallics formed around the bonded interface and in the reacted compact were identified by energy dispersive spectroscopy (EDS) and electron probe micro analysis (EPMA).Si rich layer was formed on the Al alloy side near the bonded interface by the sequential solidification of Al alloy. The porosities observed in the reacted Ni3Al compact were filled up with the liquid Al alloy. The Si particles from the molten Al alloy were detected in the pores of reacted Ni3Al intermetallic compact. The Al casting alloy and Ni3Al intermetallic compound were joined very soundly by applying pressure to the liquid Al alloy.

  3. Effect of rolling temperature on microstructure and mechanical properties of 6063 Al alloy

    Energy Technology Data Exchange (ETDEWEB)

    Panigrahi, S.K. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Roorkee, Roorkee 247667 (India); Jayaganthan, R. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Roorkee, Roorkee 247667 (India)], E-mail: rjayafmt@iitr.ernet.in

    2008-09-25

    Aluminium alloy (6063) was severely rolled upto 92% thickness reduction at liquid nitrogen temperature and room temperature to study the effect of rolling temperature on its mechanical properties and microstructural characteristics by using tensile tests and SEM/electron back scattered diffraction (EBSD), transmission electron microscope (TEM), DSC, X-ray diffraction (XRD) as compared to room temperature rolled (RTR) material with the same deformation strain. An improved strength (257 MPa) of cryorolled 6063 Al alloy was observed as compared to the room temperature rolled alloy (232 MPa). The improved strength of cryorolled alloy is due to the accumulation of higher dislocation density than the room temperature rolled material. The tensile properties of cryorolled alloy and the alloy subjected to different annealing treatments were measured. The cryorolled alloy subjected to annealing treatment at 300 deg. C for 5 min exhibits an ultrafine-grained (UFG) microstructure with improved tensile strength and ductility.

  4. Microstructural Evolution of 6061 Alloy during Isothermal Heat Treatment

    Institute of Scientific and Technical Information of China (English)

    Na Wang; Zhimin Zhou; Guimin Lu

    2011-01-01

    The semi-solid billet of 6061 aluminum alloy was prepared by the near-liquidus semi-continuous casting (LSC) with rosette or near-spheroide grains. The pre-deformation processing was applied before partial remelting to further improve the microstructure and properties of the semi-solid alloy. The efiects of different processing parameters, such as holding temperature and holding time, on the semisolid microstructures during partial remelting have been investigated. It was found that the optimal partial remelting parameters should be 630℃ and 10-15 min for 6061 alloy cold rolled with 60% reduction in height of pre-deformation. The coarsening rates were anasysed by Lifshitz-Slyozov-Wagner (LSW) theory. The pre-deformed 6061 alloy exhibits lower coarsening rate constants than that of the as-cast one, and also lower than other alloys processed by different method found in previous literature. It is because the coarsening rate is associated with the initial microstructure and composition of the alloy. The secondary phases in the alloy inhibit the migration of the liquid film grain boundaries. The microstructure obtained by using the combination of near-liquidus semicontinuous casting and pre-deformation treatment is better than that without pre-deformation processing, which demonstrates that the used method is promising for fabricating high quality semi-solid alloys.

  5. Model for calculation of microstructural development in rapidly directionally solidified immiscible alloys

    Institute of Scientific and Technical Information of China (English)

    赵九洲

    2002-01-01

    A model has been developed for the calculation of the microstructural evolution in a rapidly directionally solidified immiscible alloy. Numerical solutions have been performed for Al-Pb immiscible alloys. The results demonstrate that at a higher solidification velocity a constitutional supercooling region appears in front of the solid/liquid interface and the liquid-liquid decomposition takes place in this region. A higher solidification velocity leads to a higher nucleation rate and, therefore, a higher number density of the minority phase droplets. As a result, the average radius of droplets in the melt at the solid/liquid interface decreases with the solidification velocity.

  6. Assessment Of Usability Of Molten Salt Mixtures In Metallurgy Of Aluminum Alloys And Recycling Of Composite Materials Based On The Matrix Of Al Alloys

    Directory of Open Access Journals (Sweden)

    Jackowski J.

    2015-09-01

    Full Text Available Effectiveness of the slags used in metallurgy of aluminum alloys and in recycling of composite materials containing these alloys depends on their surface properties at the phase boundaries they are in contact with. An index of surface properties of molten mixtures of slag-forming salts has been formulated. Its calculated values are compared with measured results of surface tension (liquid – atmosphere and interfacial tension (liquidliquid in the considered systems. It was found that the index can be helpful for purposes of proper choice of the mixtures of slag-forming salts used both in Al alloys metallurgy and in recycling of composite materials based on the matrix of Al alloys.

  7. Environmentally Asisted Cracking Behavior of Nickel Alloys in Simulated Acidic and Alkaline Ground Waters Using U-bend Specimens

    Energy Technology Data Exchange (ETDEWEB)

    Fix, D V; Estill, J C; Hust, G A; Wong, L L; Rebak, R B

    2003-10-17

    The model for the degradation of the containers for nuclear waste includes three modes of corrosion, namely general corrosion, localized corrosion and environmentally assisted cracking (EAC). The objective of the current research was to quantify the susceptibility of five nickel alloys to EAC in several environmental conditions with varying solution composition, temperature and electrochemical potential. These alloys included: Alloy 22 (N06022), Alloy C-4 (N06455), Alloy 625 (N06625), Alloy G-3 (N06985) and Alloy 825 (N08825). The susceptibility to EAC was evaluated using constant deformation (deflection) U-bend specimens in both the non-welded (wrought) and welded conditions. Results show that after more than five years exposure in the vapor and liquid phases of alkaline (pH {approx} 10) and acidic (pH {approx} 3) multi-ionic environments at 60 C and 90 C, none of the tested alloys suffered environmentally assisted cracking.

  8. Catalyst Alloys Processing

    Science.gov (United States)

    Tan, Xincai

    2014-10-01

    Catalysts are one of the key materials used for diamond formation at high pressures. Several such catalyst products have been developed and applied in China and around the world. The catalyst alloy most widely used in China is Ni70Mn25Co5 developed at Changsha Research Institute of Mining and Metallurgy. In this article, detailed techniques for manufacturing such a typical catalyst alloy will be reviewed. The characteristics of the alloy will be described. Detailed processing of the alloy will be presented, including remelting and casting, hot rolling, annealing, surface treatment, cold rolling, blanking, finishing, packaging, and waste treatment. An example use of the catalyst alloy will also be given. Industrial experience shows that for the catalyst alloy products, a vacuum induction remelt furnace can be used for remelting, a metal mold can be used for casting, hot and cold rolling can be used for forming, and acid pickling can be used for metal surface cleaning.

  9. PLUTONIUM-ZIRCONIUM ALLOYS

    Science.gov (United States)

    Schonfeld, F.W.; Waber, J.T.

    1960-08-30

    A series of nuclear reactor fuel alloys consisting of from about 5 to about 50 at.% zirconium (or higher zirconium alloys such as Zircaloy), balance plutonium, and having the structural composition of a plutonium are described. Zirconium is a satisfactory diluent because it alloys readily with plutonium and has desirable nuclear properties. Additional advantages are corrosion resistance, excellent fabrication propenties, an isotropie structure, and initial softness.

  10. NICKEL-BASE ALLOY

    Science.gov (United States)

    Inouye, H.; Manly, W.D.; Roche, T.K.

    1960-01-19

    A nickel-base alloy was developed which is particularly useful for the containment of molten fluoride salts in reactors. The alloy is resistant to both salt corrosion and oxidation and may be used at temperatures as high as 1800 deg F. Basically, the alloy consists of 15 to 22 wt.% molybdenum, a small amount of carbon, and 6 to 8 wt.% chromium, the balance being nickel. Up to 4 wt.% of tungsten, tantalum, vanadium, or niobium may be added to strengthen the alloy.

  11. Liquid metal embrittlement mechanism

    Institute of Scientific and Technical Information of China (English)

    周国辉; 刘晓敏; 万发荣; 乔利杰; 褚武扬; 张文清; 陈难先; 周富信

    1999-01-01

    Liquid metal embrittlement was studied in the following two aspects. First the first principle and ChenNanxian three-dimensional lattice reverse method were employed to obtain the effective potentials for Al-Ga and GaGa. Then with the molecular dynamics simulation, the influence of liquid metal adsorption on dislocation emission was studied. The simulated result shows that after Ga atoms are adsorbed on the crack plane in Al crystal, the critical stress intensity factor decreases, which changes from 0.5 MPam1/2 (without adsorption) to 0.4 MPam1/2 (with adsorption). The reason for the reduction in the critical intensity stress factor is that Ga adsorption reduces the surface energy of the crack plane. Moreover, 7075 Al alloy adsorbing liquid metal (Hg+3atm%Ga) was in-situ studied in TEM by using a special constant deflection device. The experimental result showed that liquid metal adsorption could facilitate emission, multiplication and motion of dislocations. When this process reached a critical

  12. Binary Colloidal Alloy Test-3 and 4: Critical Point

    Science.gov (United States)

    Weitz, David A.; Lu, Peter J.

    2007-01-01

    Binary Colloidal Alloy Test - 3 and 4: Critical Point (BCAT-3-4-CP) will determine phase separation rates and add needed points to the phase diagram of a model critical fluid system. Crewmembers photograph samples of polymer and colloidal particles (tiny nanoscale spheres suspended in liquid) that model liquid/gas phase changes. Results will help scientists develop fundamental physics concepts previously cloaked by the effects of gravity.

  13. Welding Metallurgy of Alloy HR-160

    Energy Technology Data Exchange (ETDEWEB)

    DuPont, J.N.; Michael, J.R.; Newbury, B.D.

    1999-05-28

    The solidification behavior and resultant solidification cracking susceptibility of autogenous gas tungsten arc fusion welds in alloy HR-160 was investigated by Varestraint testing, differential thermal analysis, and various microstructural characterization techniques. The alloy exhibited a liquidus temperature of 1387 {deg}C and initiated solidification by a primary L - {gamma} reaction in which Ni, Si, and Ti segregated to the interdendritic liquid and Co segregated to the {gamma} dendrite cores. Chromium exhibited no preference for segregation to the solid or liquid phase during solidification. Solidification terminated at {approx} 1162 {deg}C by a eutectic-type L - [{gamma}+ (Ni,Co){sub 16}(Ti,Cr){sub 6}Si{sub 7}] reaction. The (Ni,Co){sub 16}(Ti,Cr){sub 6}Si{sub 7} phase is found to be analogous to the G phase which forms in the Ni-Ti-Si and Co-Ti-Si ternary systems, and similarities are found to exist between the solidification behavior of this commercial multicomponent alloy and the simple Ni-Si and Ni-Ti binary systems. Reasonable agreement is obtained between the calculated and measured volume percent of the [{gamma} +(Ni,Co){sub l6}(Ti,Cr){sub 6}Si{sub 7}] eutectic-typr constituent with the Scheil equation using experimentally determined k values for Si and Ti from electron microprobe data. The alloy exhibited a very high susceptibility to solidification cracking in the Varestraint test. This is attributed to a large solidification temperature range of 225 {deg}C and the presence of 2 to 5 vol% solute rich interdendritic liquid which preferentially wets the grain boundaries and interdendritic regions.

  14. Containerless processing of hypermonotectic and glass forming alloys using the Marshall Space Flight Center 100 meter drop tube facility

    Science.gov (United States)

    Andrews, J. B.

    1986-01-01

    Two separate projects were carried out to study alloys whose solidification structures can be strongly influenced by the presence of a container during melting and solidifications. One project involved containerless solidification of hypermonotectic Au35Rh65 alloys. This alloy exhibits liquid immiscibility over a temperature range. It has been suggested that containerless melting might be one solution to the problem of sedimentation in the dispersions of immiscible liquid phases. However, surface tension driven flows could also lead to accumulation of the minority liquid phase at the external surface of a containerlessly melted alloy. The research underway is a first step in determining the influence of containerless, microgravity processing on immiscible alloys. Nickel-niobium alloys were studied using the drop tube facility. One alloy in this system, a Ni60Nb40 alloy, is a good candidate for the formation of a bulk metallic glass. Amorphous alloys of this composition were produced using thin film and mechanical alloying techniques. However, theory indicates that if heterogeneous nucleation can be avoided, it should be possible to produce an amorphous structure in this system using a moderate cooling rate from the melt. The containerless melting and solidification capabilities of the drop tube faciltiy provide ideal conditions for a study of this type. To date, several Ni60Nb40 samples have been levitated, melted and cooled during 4.6 seconds of free fall in the 100 meter drop tube. Structures obtained are discussed.

  15. Method for fabricating a seal between a ceramic and a metal alloy

    Science.gov (United States)

    Kelsey, P.V. Jr.; Siegel, W.T.

    1983-08-16

    A method of fabricating a seal between a ceramic and an alloy comprising the steps of prefiring the alloy in an atmosphere with a very low partial pressure of oxygen, firing the assembled alloy and ceramic in air, and gradually cooling the fired assembly to avoid the formation of thermal stress in the ceramic. The method forms a bond between the alloy and the ceramic capable of withstanding the environment of a pressurized water reactor and suitable for use in an electrical conductivity sensitive liquid level transducer.

  16. A New Thermodynamic Calculation Method for Binary Alloys: Part I: Statistical Calculation of Excess Functions

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The improved form of calculation formula for the activities of the components in binary liquids and solid alloys has been derived based on the free volume theory considering excess entropy and Miedema's model for calculating the formation heat of binary alloys. A calculation method of excess thermodynamic functions for binary alloys, the formulas of integral molar excess properties and partial molar excess properties for solid ordered or disordered binary alloys have been developed. The calculated results are in good agreement with the experimental values.

  17. Advanced methods for preparation and characterization of infrared detector materials. [mercury cadmium telluride alloys

    Science.gov (United States)

    Lehoczky, S. L.; Szofran, F. R.

    1981-01-01

    Differential thermal analysis data were obtained on mercury cadmium telluride alloys in order to establish the liquidus temperatures for the various alloy compositions. Preliminary theoretical analyses was performed to establish the ternary phase equilibrium parameters for the metal rich region of the phase diagram. Liquid-solid equilibrium parameters were determined for the pseudobinary alloy system. Phase equilibrium was calculated and Hg(l-x) Cd(x) Te alloys were directionally solidified from pseudobinary melts. Electrical resistivity and Hall coefficient measurements were obtained.

  18. Tensile Strength of the Al-9%Si Alloy Modified with Na, F and Cl Compounds

    Directory of Open Access Journals (Sweden)

    T. Lipiński

    2010-01-01

    Full Text Available The modification of the Al-9%Si alloy with the use of a complex modifier containing Na, F and Cl was investigated in the study. The modifier was composed of NaCl, Na3AlF6 and NaF compounds. The modifier and the liquid Al-Si alloy were kept in the crucible for 15 minutes. The modifier's effect relative to the weight of the processed alloy on its tensile strength was presented in graphic form. The results of the study indicate that the complex modifier altered the investigated properties of the eutectic Al-9%Si alloy.

  19. Formation and crystallization of bulk Pd82Si18 amorphous alloys

    Institute of Scientific and Technical Information of China (English)

    蒲建; 王敬丰; 肖建中; 崔昆

    2003-01-01

    Bulk amorphous Pd82Si18 alloy with the largest diameter of 8 mm was prepared by water quenching the molten alloy with flux medium in a quartz tube. The calculation result indicates that the bulk Pd82Si18 amorphous alloys have a low critical cooling rate (Rc) of 4.589 K/s or less. The experimental results show that purifying melt may improve glass forming ability(GFA) of undercooled melt, while liquid phase separation (LPS) of undercooled melt will decrease its GFA. There are some differences in crystallization experiments between bulk metallic glass and amorphous ribbons of Pd82Si18 alloys. These include the numbers of exothermic peak, glass transition temperature Tg, crystallization temperature Tx, region of undercooling liquid (ΔT=Tx-Tg) respectively. The links of cooling rates of melt and crystallization of Pd82Si18 amorphous alloys are explored.

  20. Rapid solidification of immiscible alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bosco, Enrica; Rizzi, Paola; Baricco, Marcello E-mail: marcello.baricco@unito.it

    2003-05-01

    Immiscible alloys have been rapidly solidified for the preparation of granular materials with giant magnetoresistance properties. Au-based (Au-Co and Au-Fe) and Cu-based (Cu-Co and Cu-Fe) systems have been investigated. Single supersaturated solid solution has been obtained for Au-Fe, whereas three FCC solid solutions with different Co content have been found for Au-Co. For Cu-Co and Cu-Fe a limit of solubility in Cu has been observed. Ni additions to Cu-Fe strongly enhance solid solubility. A thermodynamic analysis has been used to describe the competition between partition-less solidification and phase separation in undercooled liquid.

  1. Role of alloying additions on the properties of Cu–Al–Mn shape memory alloys

    Energy Technology Data Exchange (ETDEWEB)

    Dasgupta, Rupa, E-mail: rupadasgupta@ampri.res.in; Jain, Ashish Kumar; Kumar, Pravir; Hussain, Shahadat; Pandey, Abhishek

    2015-01-25

    Highlights: • Cu based SMAs with high transition temperature could be made using LM route. • The properties depend on alloying composition. • Property characterisation establishes feasibility of making SMAs. - Abstract: The effect of alloying seven different elements [Zn, Si, Fe, Ni, Mg, Cr and Ti] on the microstructure, hardness, phase precipitation and transformation temperature in a Cu–12.5Al–5Mn alloy with a view to possible improvements as a result of these additions is the focus of the reported study. The base alloy has been chosen keeping in mind its ability to exhibit shape memory properties and improved ductility over other Cu-based SMAs. The objective was to ascertain changes or improvements attained due to the individual tertiary additions. The samples were prepared through liquid metallurgy route using pure copper, aluminum, manganese and the respective quaternary alloying elements in right quantities to weigh 1000 g of the alloy in total and were melted together. Samples from the cast alloys were subject to homogenisation treatment at 200 °C for 2 h in a muffle furnace and furnace cooled. Samples from the homogenised alloys were heated and held for 2 h at 920 °C followed by ice quenching to obtain the desired martensitic structure for shape memory behaviour. The alloys in the cast, homogenised and quenched conditions were metallographically polished to observe the martensitic phase formation mainly in quenched samples which is a pre requisite for exhibiting shape memory properties in these alloys. X-ray Diffraction studies were carried out on the cast and quenched samples using Cu Kα target; and the phases identified indicate martensitic phase precipitation; however in some cases the precipitation is incomplete. Differential Scanning Calorimetric [DSC] studies were carried out on quenched samples from room temperature to 600 °C maintaining a constant rate of 10 °C/min. Results indicate clear transformation peaks in all the samples which

  2. Hollow platinum alloy tailored counter electrodes for photovoltaic applications

    Science.gov (United States)

    Li, Pinjiang; Zhang, Yange; Fa, Wenjun; Yang, Xiaogang; Wang, Liang

    2017-08-01

    Without sacrifice of photovoltaic performances, low-platinum alloy counter electrodes (CEs) are promising in bringing down the fabrication cost of dye-sensitized solar cells (DSSCs). We present here the realization of ZnO nanostructure assisted hollow platinum-nickel (PtNi) alloy microstructure CEs with a simple hydrothermal methods and maximization of electrocatalytic behaviors by tuning Zn precursors. The maximal power conversion efficiency is up to 8.74% for the liquid-junction dye-sensitized solar cells with alloyed PtNi0.41 electrode, yielding a 37.6% cell efficiency enhancement in comparison with pristine solar cell from planar Pt electrode. Moreover, the dissolution-resistant and charge-transfer abilities toward I-/I3- redox electrolyte have also been markedly enhanced due to competitive dissolution reactions and alloying effects.

  3. Ductile transplutonium metal alloys

    Science.gov (United States)

    Conner, William V.

    1983-01-01

    Alloys of Ce with transplutonium metals such as Am, Cm, Bk and Cf have properties making them highly suitable as sources of the transplutonium element, e.g., for use in radiation detector technology or as radiation sources. The alloys are ductile, homogeneous, easy to prepare and have a fairly high density.

  4. Use of sodium salt electrolysis in the process of continuous modification of eutectic EN AC-AlSi12 alloy

    Indian Academy of Sciences (India)

    J Pezda; A Białobrzeski

    2015-04-01

    This paper presents test results concerning the selection of sodium salt for the technology of continuous modification of the EN AC-AlSi12 alloy, which is based on electrolysis of sodium salts, occurring directly in a crucible with liquid alloy. Sodium ions formed as a result of the sodium salt dissociation and the electrolysis are 'transferred' through walls of the retort made of solid electrolyte. Upon contact with the liquid alloy, which functions as a cathode, sodium ions are transformed into the atomic state, modifying the alloy. As a measure of the alloy modification extent, the obtained increase of the tensile strength m and change of metallographic structure are used, confirming obtained modification effect of the investigated alloy.

  5. 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.

  6. Mg based alloys obtained by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez, S. [Univ. de Santiago de Chile (Chile). Fac. de Ingenieria; Garcia, G.; Serafini, D.; San Martin, A.

    1999-07-01

    In the present work, we studied the production of magnesium alloys, of stoichiometry 2Mg + Ni, by mechanical alloying (MA) and the behavior of the alloys under hydrogen in a Sievert`s type apparatus. The elemental powders were milled under argon atmosphere in a Spex 8000 high energy ball mill. The milled materials were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Only minimum amounts of the Mg{sub 2}Ni intermetallic compound was obtained after 22 h of milling time. Most of the material was sticked to the inner surface of the container as well as to the milling balls. Powders milled only for 12 hours transforms to the intermetallic at around 433 K. Effects of the MA on the hydrogen absorption kinetics were also studied. (orig.) 10 refs.

  7. A New Model for Microstructure of Liquid Metals

    Institute of Scientific and Technical Information of China (English)

    田学雷; 沈军; 孙剑飞; 李庆春

    2004-01-01

    A nanocrystalline model for microstructures of liquid metals is constructed. According to the nanocrystalline model, the intensity curves of x-ray diffraction (XRD) on liquid Cu, Al and Al65Cu20Fe15 alloy are derived by broadening the XRD peaks of these metals in some crystal structures. These broadening intensity curves are identical with the results measured by an x-ray diffractometer on these liquid metals. The present results indicate that the nanocrystal model may be helpful to understand the microstructures of liquid metals and that there is aclose correlation between the short-range orders (SROs) of these liquid metals and some crystal lattice structures.That is, the SRO structures of liquid Cu, Al and Al65Cu20Fe15 alloy are fcc, bcc and icosahedron, respectively.

  8. Effect of yttrium on the microstructure of a semi-solid A356 Al alloy

    Institute of Scientific and Technical Information of China (English)

    LIU Zheng; HU Yongmei

    2008-01-01

    The semi-solid slurry of an A356 Al alloy,which was grain-freed by yttrium,was manufactured by low temperature pouring.The effects of grain-refining on the morphology and the grain size of the primary α phase in the semi-solid A356 Al alloy were researched.The results indicate that the semi-solid A356 Al alloy with particle-like and rosette-like primary α-Al can be prepared by low temperature pouring from a liquid grain-refined A356 alloy.The grain size and particle morphology of primary α-Al in the A356 Al alloy are markedly improved by the addition of 0.5 wt.% Y.The fining mechanism of Y on the morphology and grain size of the primary α-Al in the semi-solid A356 Al alloy was delved.

  9. Liquid phase surface melting of AA8011 aluminum alloy by addition of Al/Al{sub 2}O{sub 3} nano-composite powders synthesized by high-energy milling

    Energy Technology Data Exchange (ETDEWEB)

    Sohi, M. Heydarzadeh [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Hojjatzadeh, S.M.H., E-mail: Hojatzadeh@yahoo.com [Department of Welding, Science and Research Branch, Azad University, Tehran (Iran, Islamic Republic of); Moosavifar, Sh. S.; Heshmati-Manesh, S. [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)

    2014-09-15

    Highlights: • Aluminum matrix composite layers reinforced with alumina particles were fabricated. • Non milled powders caused porosity in the microstructures because of poor wettability. • The ball milling of powders was significantly improved the wettability of nano ceramic particles. • The micro hardness of the layers was approximately 3 times greater than that of the base metal. - Abstract: Poor wettability of particles is an obstacle in formation of sound composite layer via surface melting. Pre-coating of particles with metallic material by different techniques, such as ball milling may enhance the wettability of the particles with molten metal. In this study, composite surface layers containing Al{sub 2}O{sub 3} particles were fabricated on the surface of AA8011 aluminum substrates by tungsten inert gas (TIG) surface melting using preplaced layers of Al/Al{sub 2}O{sub 3} powder mixtures in two different forms: (1) a mixture of 40 wt% Al and 60 wt% of 50 nm Al{sub 2}O{sub 3} powders and (2) a mixture obtained by mechanical alloying of 40 wt% Al and 60 wt% of 60 μm Al{sub 2}O{sub 3} powders. Morphology evolution of powders during ball milling and the microstructure of the fabricated composite layers were studied through conventional characterization techniques, such as optical microscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD). Microhardness measurements were also performed across the alloyed zone. The results indicated that the layer fabricated by the second route showed a defect free structure with a more uniform distribution of Al{sub 2}O{sub 3} particles in comparison with the layer obtained by the first route. It was also noticed that the uniform dispersion of Al{sub 2}O{sub 3} particles in the fabricated layer increased the hardness to 133 HV which was over 3 times of that of the base metal.

  10. First-principles molecular dynamics simulation of liquid Mg3Bi2

    NARCIS (Netherlands)

    deWijs, GA; Pastore, G; Selloni, A; vanderLugt, W

    1996-01-01

    The liquid Mg-Bi system exhibits strong compound formation at the 'octet' composition (Mg3Bi2) We present results of first-principles molecular dynamics simulations of this alloy system at different compositions: the pure Mg and Bi liquid components, the stoichiometric liquid, and a Mg-rich composit

  11. POLY-ANIONS IN LIQUID CSPB - AN AB-INITIO MOLECULAR-DYNAMICS SIMULATION

    NARCIS (Netherlands)

    DEWIJS, GA; PASTORE, G; SELLONI, A; VANDERLUGT, W

    1994-01-01

    Most alkali-group-IV liquid alloys exhibit strong chemical effects leading to well-defined equiatomic compounds. This is generally explained by the survival of particular clusters of lead-''Zintl'' ions-in the liquid state. We report on an ab initio simulation of liquid CsPb, for which the chemical

  12. Evolution of atomic structure in Al75Cu25 liquid from experimental and ab initio molecular dynamics simulation studies.

    Science.gov (United States)

    Xiong, L H; Yoo, H; Lou, H B; Wang, X D; Cao, Q P; Zhang, D X; Jiang, J Z; Xie, H L; Xiao, T Q; Jeon, S; Lee, G W

    2015-01-28

    X-ray diffraction and electrostatic levitation measurements, together with the ab initio molecular dynamics simulation of liquid Al(75)Cu(25) alloy have been performed from 800 to 1600 K. Experimental and ab initio molecular dynamics simulation results match well with each other. No abnormal changes were experimentally detected in the specific heat capacity over total hemispheric emissivity and density curves in the studied temperature range for a bulk liquid Al(75)Cu(25) alloy measured by the electrostatic levitation technique. The structure factors gained by the ab initio molecular dynamics simulation precisely coincide with the experimental data. The atomic structure analyzed by the Honeycutt-Andersen index and Voronoi tessellation methods shows that icosahedral-like atomic clusters prevail in the liquid Al(75)Cu(25) alloy and the atomic clusters evolve continuously. All results obtained here suggest that no liquid-liquid transition appears in the bulk liquid Al(75)Cu(25) alloy in the studied temperature range.

  13. SURFACE MELTING OF ALUMINIUM ALLOYS

    OpenAIRE

    Veit, S.; Albert, D; Mergen, R.

    1987-01-01

    The wear properties of aluminium base alloys are relatively poor. Laser surface melting and alloying has proved successful in many alloy systems as a means of significantly improving the surface properties. The present work describes experiments designed to establish the scope of laser treatment of aluminium alloys. Aluminium does not absorb CO2 laser light as well as other metals which necessitated first a general study of absorption caotings. Aluminium alloys offer fewer opportunities than ...

  14. Crystalline 'Genes' in Metallic Liquids

    CERN Document Server

    Sun, Yang; Ye, Zhuo; Fang, Xiaowei; Ding, Zejun; Wang, Cai-Zhuang; Mendelev, Mikhail I; Ott, Ryan T; Kramer, M J; Ho, Kai-Ming

    2014-01-01

    The underlying structural order that transcends the liquid, glass and crystalline states is identified using an efficient genetic algorithm (GA). GA identifies the most common energetically favorable packing motif in crystalline structures close to the alloy's Al-10 at.% Sm composition. These motifs are in turn compared to the observed packing motifs in the actual liquid structures using a cluster-alignment method which reveals the average topology. Conventional descriptions of the short-range order, such as Voronoi tessellation, are too rigid in their analysis of the configurational poly-types when describing the chemical and topological ordering during transition from undercooled metallic liquids to crystalline phases or glass. Our approach here brings new insight into describing mesoscopic order-disorder transitions in condensed matter physics.

  15. Market Liquidity and Funding Liquidity

    OpenAIRE

    Brunnermeier, Markus K; Lasse Heje Pedersen

    2007-01-01

    We provide a model that links an asset's market liquidity - i.e., the ease with which it is traded - and traders' funding liquidity - i.e., the ease with which they can obtain funding. Traders provide market liquidity, and their ability to do so depends on their availability of funding. Conversely, traders' funding, i.e., their capital and the margins they are charged, depend on the assets' market liquidity. We show that, under certain conditions, margins are destabilizing and market liquidit...

  16. Market Liquidity and Funding Liquidity

    OpenAIRE

    Markus K. Brunnermeier; Lasse Heje Pedersen

    2007-01-01

    We provide a model that links an asset's market liquidity - i.e., the ease with which it is traded - and traders' funding liquidity - i.e., the ease with which they can obtain funding. Traders provide market liquidity, and their ability to do so depends on their availability of funding. Conversely, traders' funding, i.e., their capital and the margins they are charged, depend on the assets' market liquidity. We show that, under certain conditions, margins are destabilizing and market liquidit...

  17. Experimental evidence of Alfven wave propagation in a Gallium alloy

    OpenAIRE

    2011-01-01

    10p.; International audience; Experiments with a liquid metal alloy, galinstan, are reported and show clear evidence of Alfvén wave propagation as well as resonance of Alfvén modes. Galinstan is liquid at room temperature, and although its electrical conductivity is not as large as that of liquid sodium or NaK, it has still been possible to study Alfvén waves, thanks to the use of intense magnetic fi elds, up to 13 teslas. The maximal values of Lundquist number, around 60, are similar to that...

  18. Corrosion behavior of Mg-Zn-Ca amorphous alloys with Nd addition in simulated body fluids

    Directory of Open Access Journals (Sweden)

    Qin Chunling

    2014-11-01

    Full Text Available The effects of Nd addition on corrosion behavior of Mg66Zn30Ca4 amorphous alloys in simulated body fluids (SBF were studied in this paper. Electrochemical properties of the samples before and after corrosion were determined. Surface morphologies of samples after immersion in SBF at 37 篊 for different times were observed under scanning electron microscope (SEM. Results show that the corrosion resistance of Mg-based alloys in SBF is improved with the addition of Nd element. The electrochemical properties indicate that microalloying Nd element to the alloys leads to an ennoblement in the open circuit potentials of the alloys and a decrease in the anodic current density in SBF, especially for the Mg66-xZn30Ca4Ndx alloys with Nd content of 1.0at.%-1.5at.%. It was observed that the surface morphologies of the alloys immersed in SBF change with the Nd addition. A flake-like structure parallel to the alloy substrate formed on the surface of 1.0at.% Nd-containing alloy immersed in SBF for 7 days improves the corrosion resistance of the amorphous alloys by blocking the corrosion liquid from attacking the alloys.

  19. Description Of Alloy Layer Formation On A Cast Steel Substrate

    Directory of Open Access Journals (Sweden)

    Szajnar J.

    2015-09-01

    Full Text Available A description of alloy layer formation on a steel substrate is presented. Two types of formation are considered: diffusion of carbon and chromium into the solid from the pad in the direction of the cast steel within the FeCrC (grains and diffusion in a layer of liquid chromium cast iron formed in a preceding step. The influence of silicon in the pad on the pad’s transformation into the liquid is also examined. Solidus and liquidus temperatures of high carbon ferrochromium are determined. The larger the content of Si is used in the experiment, the lower the solidus temperature of the FeCrC alloy is observed. This results from the higher intensity of the elements’ diffusion and faster formation of the liquid.

  20. Analysis of niobium alloys.

    Science.gov (United States)

    Ferraro, T A

    1968-09-01

    An ion-exchange method was applied to the analysis of synthetic mixtures representing various niobium-base alloys. The alloying elements which were separated and determined include vanadium, zirconium, hafnium, titanium, molybdenum, tungsten and tantalum. Mixtures containing zirconium or hafnium, tungsten, tantalum and niobium were separated by means of a single short column. Coupled columns were employed for the resolution of mixtures containing vanadium, zirconium or titanium, molybdenum, tungsten and niobium. The separation procedures and the methods employed for the determination of the alloying elements in their separate fractions are described.

  1. TUNGSTEN BASE ALLOYS

    Science.gov (United States)

    Schell, D.H.; Sheinberg, H.

    1959-12-15

    A high-density quaternary tungsten-base alloy having high mechanical strength and good machinability composed of about 2 wt.% Ni, 3 wt.% Cu, 5 wt.% Pb, and 90wt.% W is described. This alloy can be formed by the powder metallurgy technique of hot pressing in a graphite die without causing a reaction between charge and the die and without formation of a carbide case on the final compact, thereby enabling re-use of the graphite die. The alloy is formable at hot- pressing temperatures of from about 1200 to about 1350 deg C. In addition, there is little component shrinkage, thereby eliminating the necessity of subsequent extensive surface machining.

  2. Whisker Formation in Porosity in Al Alloys

    Science.gov (United States)

    Griffiths, William David; Elsayed, Ahmed; El-Sayed, Mahmoud Ahmed

    2016-12-01

    An examination of the fracture surfaces of tensile test bars from Al alloy castings held in the liquid state for up to 20 minutes revealed porosity which in some cases contained whisker-like features. Energy-dispersive X-ray analysis in a SEM suggested that these might be oxide whiskers forming in an oxide-related pore or double oxide film defect. Such entrainment defects (also known as bifilms) may entrap a small amount of the local atmosphere when they form and become incorporated into the liquid metal. This atmosphere may be predominantly air, which then subsequently reacts with the surrounding melt, firstly by reaction with oxygen and secondly by reaction with nitrogen. A CFD model of the heat distribution associated with the reactions between the interior atmosphere of a double oxide film defect and the surrounding liquid alloy suggested that highly localized increases in temperature, up to about 2000 K to 5000 K (1727 °C to 4727 °C), could occur, over a scale of a few hundred micrometers. Such localized increases in temperature might lead to the evaporation or disassociation of oxide within the pore, followed by condensation, to form the whisker structures observed. Hydrogen might also be expected to diffuse into the bifilm and may play a role in the chemical reactions associated with the development of the bifilm.

  3. A new coupled model for alloy solidification

    Institute of Scientific and Technical Information of China (English)

    LI Daming; LI Ruo; ZHANG Pingwen

    2004-01-01

    A new coupled model in the binary alloy solidification has been developed. The model is based on the cellular automaton (CA)technique to calculate the evolution of the interface governed by temperature, solute diffusion and Gibbs-Thomson effect. The diffusion equation of temperature with the release of latent heat on the solid/liquid (S/L) interface is valid in the entire domain.The temperature diffusion without the release of latent heat and solute diffusion are solved in the entire domain. In the interface cells, the energy and solute conservation, thermodynamic and chemical potential equilibrium are adopted to calculate the temperature, solid concentration, liquid concentration and the increment of solid fraction. Compared with other models where the release of latent heat is solved in implicit or explicit form according to the solid/liquid (S/L) interface velocity, the energy diffusion and the release of latent heat in this model are solved at differentscales, I.e. The macro-scale and micro-scale. The variation ofsolid fraction in this model is solved using several algebraicrelations coming from the chemical potential equilibrium andthermodynamic equilibrium which can be cheaply solved insteadof the calculation of S/L interface velocity. With the assumptionof the solute conservation and energy conservation, the solidfraction can be directly obtained according to the thermodynamicdata. This model is natural to be applied to multiple (>2)spatial dimension case and multiple (>2) component alloy. Themorphologies of equiaxed dendrite are obtained in numericalexperiments.

  4. Standard Specification for Copper-Aluminum-Silicon-Cobalt Alloy, Copper-Nickel-Silicon-Magnesium Alloy, Copper-Nickel-Silicon Alloy, Copper-Nickel-Aluminum-Magnesium Alloy, and Copper-Nickel-Tin Alloy Sheet and Strip

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2015-01-01

    Standard Specification for Copper-Aluminum-Silicon-Cobalt Alloy, Copper-Nickel-Silicon-Magnesium Alloy, Copper-Nickel-Silicon Alloy, Copper-Nickel-Aluminum-Magnesium Alloy, and Copper-Nickel-Tin Alloy Sheet and Strip

  5. Environmentally Assisted Cracking of Nickel Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, R B

    2004-02-06

    Environmentally Assisted Cracking (EAC) is a general term that includes phenomena such as stress corrosion cracking (SCC), hydrogen embrittlement (HE), sulfide stress cracking (SSC), liquid metal embrittlement (LME), etc. EAC refers to a phenomenon by which a normally ductile metal looses its toughness (e.g. elongation to rupture) when it is subjected to mechanical stresses in presence of a specific corroding environment. For EAC to occur, three affecting factors must be present simultaneously. These include: (1) Mechanical tensile stresses, (2) A susceptible metal microstructure and (3) A specific aggressive environment. If any of these three factors is removed, EAC will not occur. That is, to mitigate the occurrence of EAC, engineers may for example eliminate residual stresses in a component or limit its application to certain chemicals (environment). The term environment not only includes chemical composition of the solution in contact with the component but also other variables such as temperature and applied potential. Nickel alloys are in general more resistant than stainless steels to EAC. For example, austenitic stainless steels (such as S30400) suffer SCC in presence of hot aqueous solutions containing chloride ions. Since chloride ions are ubiquitous in most industrial applications, the use of stressed stainless steels parts is seriously limited. On the other hand, nickel alloys (such as N10276) are practically immune to SCC in presence of hot chloride solutions and therefore an excellent alternative to replace the troubled stainless steels. Nonetheless, nickel alloys are not immune to other types of EAC. There are several environments (such as hot caustic and hot hydrofluoric acid) that may produce embrittlement in nickel alloys (Crum et al, 2000) (Table 1). The conditions where nickel alloys suffer EAC are highly specific and therefore avoidable by the proper design of the industrial components.

  6. Evolution of Globular Microstructure and Rheological Properties of Stellite™ 21 Alloy after Heating to Semisolid State

    Science.gov (United States)

    Sołek, Krzysztof Piotr; Rogal, Łukasz; Kapranos, Platon

    2016-11-01

    Metal alloys can be successfully thixoformed in the partially liquid state if they display non-dendritic near-globular microstructures. The article presents the development of feedstock with such non-dendritic microstructure produced through the solid-state route of strain-induced melt-activated (SIMA) method, for a Stellite™ 21 alloy. Stellite™ alloys are a range of cobalt-chromium alloys designed for wear and corrosion resistance, currently shaped by casting, powder metallurgy or forging processes, but semisolid-state processing offers the possibility of a near-net-shaping method for these alloys. In this work, sprayformed followed by extrusion samples were heated to the temperature range at which the liquid and solid phases coexist in the material and spheroidal shape solid particles in a liquid matrix were obtained as required for semisolid processing. Microstructural investigations were carried out using scanning electron microscopy (SEM) in combination with energy-dispersive spectroscopy (EDS), with a further objective of analyzing the rheological properties of Stellite™ 21 alloy in the semisolid state, providing results to be used for identification of a processing window of temperature and viscosity ranges for thixoforming this alloy.

  7. Actively convected liquid metal divertor

    Science.gov (United States)

    Shimada, Michiya; Hirooka, Yoshi

    2014-12-01

    The use of actively convected liquid metals with j × B force is proposed to facilitate heat handling by the divertor, a challenging issue associated with magnetic fusion experiments such as ITER. This issue will be aggravated even more for DEMO and power reactors because the divertor heat load will be significantly higher and yet the use of copper would not be allowed as the heat sink material. Instead, reduced activation ferritic/martensitic steel alloys with heat conductivities substantially lower than that of copper, will be used as the structural materials. The present proposal is to fill the lower part of the vacuum vessel with liquid metals with relatively low melting points and low chemical activities including Ga and Sn. The divertor modules, equipped with electrodes and cooling tubes, are immersed in the liquid metal. The electrode, placed in the middle of the liquid metal, can be biased positively or negatively with respect to the module. The j × B force due to the current between the electrode and the module provides a rotating motion for the liquid metal around the electrodes. The rise in liquid temperature at the separatrix hit point can be maintained at acceptable levels from the operation point of view. As the rotation speed increases, the current in the liquid metal is expected to decrease due to the v × B electromotive force. This rotating motion in the poloidal plane will reduce the divertor heat load significantly. Another important benefit of the convected liquid metal divertor is the fast recovery from unmitigated disruptions. Also, the liquid metal divertor concept eliminates the erosion problem.

  8. Modeling Material Properties of Lead-Free Solder Alloys

    Science.gov (United States)

    Guo, Zhanli; Saunders, Nigel; Miodownik, Peter; Schillé, Jean-Philippe

    2008-01-01

    A full set of physical and thermophysical properties for lead-free solder (LFS) alloys have been calculated, including liquidus/solidus temperatures, fraction solid, density, coefficient of thermal expansion, thermal conductivity, Young’s modulus, viscosity, and liquid surface tension, all as a function of composition and temperature (extending into the liquid state). The results have been extensively validated against data available in the literature. A detailed comparison of the properties of two LFS alloys Sn-20In-2.8Ag and Sn-5.5Zn-4.5In-3.5Bi with Sn-37Pb has been made to show the utility and need for calculations that cover a wide range of properties, including the need to consider the effect of nonequilibrium cooling. The modeling of many of these properties follows well-established procedures previously used in JMatPro software for a range of structural alloys. This paper describes an additional procedure for the calculation of the liquid surface tension for multicomponent systems, based on the Butler equation. Future software developments are reviewed, including the addition of mechanical properties, but the present calculations can already make a useful contribution to the selection of appropriate new LFS alloys.

  9. Three orthogonal ultrasounds fabricate uniform ternary Al-Sn-Cu immiscible alloy

    Science.gov (United States)

    Zhai, W.; Wang, B. J.; Liu, H. M.; Hu, L.; Wei, B.

    2016-11-01

    The production of Al based monotectic alloys with uniform microstructure is usually difficult due to the large density difference between the two immiscible liquid phases, which limits the application of such alloys. Here, we apply three orthogonal ultrasounds during the liquid phase separation process of ternary Al71.9Sn20.4Cu7.7 immiscible alloy. A uniform microstructure consisting of fine secondary (Sn) phase dispersed on Al-rich matrix is fabricated in the whole alloy sample with a large size of 30 × 30 × 100 mm. The numerical calculation results indicate that the coupled effect of three ultrasounds promotes the sound pressure level and consequently enlarges the cavitation zone within the alloy melt. The strong shockwaves produced by cavitation prevent the (Sn) droplets from coalescence, and keep them suspended in the parent Al-rich liquid phase. This accounts for the formation of homogeneous composite structures. Thus the introduction of three orthogonal ultrasounds is an effective way to suppress the macrosegregation caused by liquid phase separation and produce bulk immiscible alloys with uniform structures.

  10. Alloy Selection System

    Energy Technology Data Exchange (ETDEWEB)

    None

    2001-02-01

    Software will Predict Corrosion Rates to Improve Productivity in the Chemical Industry. Many aspects of equipment design and operation are influenced by the choice of the alloys used to fabricate process equipment.

  11. Strength of Hard Alloys,

    Science.gov (United States)

    Partial replacement of titanium carbide by tantalum carbide in three-phase WC-TiC-Co alloys tends to have a favorable effect on mechanical properties such as fatigue strength under bending and impact durability.

  12. Fabrication and characterization of Ag-Cd/CdO materials produced by incorporation of CdO particles to liquid Ag-Cd alloys; Fabricacion y caracterizacion de materiales Ag-Cd/CdO producidos mediante incorporacion de particulas de CdO en aleaciones Ag-Cd liquidas

    Energy Technology Data Exchange (ETDEWEB)

    Equihua-Guillen, F.; Ruiz-Mondragon, J.; Servin-Castaneda, R.; Orozco-Gonzalez, P.; Zaldivar-Cadena, A.; Martinez-Villafane, F.; Villarreal-Garza, E. J.

    2014-04-01

    In the present work it has been investigated the kinetic behavior of internal oxidation processes of strips of Ag-Cd/CdO materials fabricated by adding CdO particles (size of 5 and 20 {mu}m) in liquid Ag-Cd alloys. It has been established the metallurgical mechanism that controls the formation of the thickness covered with CdO particles produced by internal oxidation of the Ag-Cd/CdO material. It has been developed, successfully, a metallographic preparation technique for characterizing the morphology, size and distribution of CdO particles produced by heat treatment of internal oxidation on the surface of each sample based on the distance from the original surface to the boundary of dispersed CdO particles. The material strips were sequentially roughed on its surface and the roughing thickness was measured in the cross section of each new surface to determine the number of particles per area and average particle size. (Author)

  13. A new thermodynamic expression for Gibbs free energy difference ΔG between the under-cooled liquid and on microstructure of near-eutectic Al-13wt%Si alloy

    Directory of Open Access Journals (Sweden)

    Xi Xiao

    2008-05-01

    Full Text Available Under cooling rates of 2 ℃/s and 10 ℃/s, the influences of B content on the microstructure of near eutectic Al-13.0wt%Si alloy have been investigated. Results showed that the addition of boron resulted in refi nement of eutectic grains, and to some extent, had an inhibiting effect on precipitation of the primary phases, and the refi ning and inhibiting effects are much more obvious at higher cooling rate. When B was not added, higher cooling rate promoted the a-Al dendrites formation. At lower cooling rate, the addition of B did not cause the so called "columnar to equiaxed transition (CET", however, at higher cooling rate, this transition was obvious. After the addition of B, the nucleation temperature TN ascended and nucleation mode changed from nucleation mode of from wall towards centre (without B addition to a nucleation mode that the eutectic nucleated evenly throughout whole sample (with B added. It can be concluded that the addition of B offers a large amount of nuclei for eutectic solidifi cation, as a result, the eutectic grains was refi ned. Higher cooling rate will lead to more nuclei, so the effects on the refi nement of eutectic grains and on suppression of primary phases are increased.

  14. Liquid Ventilation

    Directory of Open Access Journals (Sweden)

    Qutaiba A. Tawfic

    2011-01-01

    Full Text Available Mammals have lungs to breathe air and they have no gills to breath liquids. When the surface tension at the air-liquid interface of the lung increases, as in acute lung injury, scientists started to think about filling the lung with fluid instead of air to reduce the surface tension and facilitate ventilation. Liquid ventilation (LV is a technique of mechanical ventilation in which the lungs are insufflated with an oxygenated perfluorochemical liquid rather than an oxygen-containing gas mixture. The use of perfluorochemicals, rather than nitrogen, as the inert carrier of oxygen and carbon dioxide offers a number of theoretical advantages for the treatment of acute lung injury. In addition, there are non-respiratory applications with expanding potential including pulmonary drug delivery and radiographic imaging. The potential for multiple clinical applications for liquid-assisted ventilation will be clarified and optimized in future. Keywords: Liquid ventilation; perfluorochemicals; perfluorocarbon; respiratory distress; surfactant.

  15. First Everlasting Alloy

    Institute of Scientific and Technical Information of China (English)

    杨仲言

    1994-01-01

    There′s new alloy that apparently just won′t give up. When a pin was scraped along it the equivalent of one million times, the alloy-made of zirconium, palladium, and ruthenium—displayed no net loss of surface material. When astonished researchers at the National Institute of Standards and Technology(NIST) persevered with a five-million-cycle wear test, they got the same result.

  16. 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.

  17. Nonlinear equations on controlling interface patterns during solidification of a dilute binary alloy

    Institute of Scientific and Technical Information of China (English)

    王自东; 周永利; 常国威; 胡汉起

    1999-01-01

    In nonequilibrium nonlinear region, by assuming that there is local equilibrium at the solid/liquid interface, and considering that curvature, temperature and composition at the solid/liquid interface which are related to perturbation amplitude are nonlinear, nonlinear equations of the time dependence of the perturbation amplitude of the solid/liquid interface during solidification of a dilute binary alloy are established. Crystal growth from nonsteady state to steady state can be controlled by these nonlinear equations.

  18. Alloy development for irradiation performance: program strategy

    Energy Technology Data Exchange (ETDEWEB)

    Bloom, E. E.; Stiegler, J. O.; Wiffen, F. W.; Dalder, E. N.C.; Reuther, T. C.; Gold, R. E.; Holmes, J. J.; Kummer, D. L.; Nolfi, F. V.

    1978-01-01

    The objective of the Alloy Development for Irradiation Performance Program is the development of structural materials for use in the first wall and blanket region of fusion reactors. The goal of the program is a material that will survive an exposure of 40 MWyr/m/sup 2/ at a temperature which will allow use of a liquid-H/sub 2/O heat transport system. Although the ultimate aim of the program is development of materials for commercial reactors by the end of this century, activities are organized to provide materials data for the relatively low performance interim machines that will precede commercial reactors.

  19. Role of temperature gradient in liquid/solid phase solution-diffusion bonding

    Institute of Scientific and Technical Information of China (English)

    翟秋亚; 徐锦锋

    2004-01-01

    The liquid-film solution-diffusion bonding of ZCuBe2.5 alloys was conducted using Cu-based alloy powders. The tensile strength of the bonding time decreases and the interface migration velocity increases bonding time, the thickness of diffusion layer increases with the increase of temperature gradient, and this tendency becomes more remarkable with the prolonging of bonding time.

  20. Supercoducting property of Zr-Cu-Al-Ni-Nb alloys

    Science.gov (United States)

    Okai, D.; Motoyama, G.; Kimura, H.; Inoue, A.

    The superconducting property of Zr55Cu(30-X)Al10Ni5NbX alloys prepared by arc melting and liquid quenching methods was investigated by magnetic susceptibility measurements. The crystalline alloys with X = 0∼25 at.% prepared by arc melting method exhibited superconductivity with maximum Tc,on of 10.1 K. The alloys (X = 10∼23 at.%) with crystalline particles embedded in an amorphous structure, which were fabricated by melt spinning method, showed superconductivity with Tc,on of less than 4.0 K. The superconducting property of the Zr-Cu-Al-Ni-Nb alloys was attributed to superconducting phases of Zr2Cu, Zr2Ni, Zr65Al10Nb25 and Zr-Nb contained in the Zr-Cu-Al-Ni-Nb alloys. The melt-spun Zr55Cu(30-X)Al10Ni5NbX (X = 10∼20 at.%) alloys exhibited glass transition at 718∼743 K and were found to be superconducting metallic glasses.

  1. Design of multi materials combining crystalline and amorphous metallic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Volland, A.; Ragani, J.; Liu, Y.; Gravier, S.; Suery, M. [Grenoble University/CNRS, SIMAP Laboratory, Grenoble INP/UJF, 38402 Saint-Martin d' Heres (France); Blandin, J.J., E-mail: jean-jacques.blandin@simap.grenoble-inp.fr [Grenoble University/CNRS, SIMAP Laboratory, Grenoble INP/UJF, 38402 Saint-Martin d' Heres (France)

    2012-09-25

    Highlights: Black-Right-Pointing-Pointer Elaboration of multi materials associating metallic glasses and conventional crystalline alloys by co-deformation performed at temperatures close to the glass transition temperature of the metallic glasses. Black-Right-Pointing-Pointer Elaboration of filamentary metal matrix composites with a core in metallic glass by co extrusion. Black-Right-Pointing-Pointer Sandwich structures produced by co-pressing. Black-Right-Pointing-Pointer Detection of atomic diffusion from the glass to the crystalline alloys during the processes. Black-Right-Pointing-Pointer Good interfaces between the metallic glasses and the crystalline alloys, as confirmed by mechanical characterisation. - Abstract: Multi materials, associating zirconium based bulk metallic glasses and crystalline metallic alloys like magnesium alloys or copper are elaborated by co-deformation processing performed in the supercooled liquid regions (SLR) of the bulk metallic glasses. Two processes are investigated: co-extrusion and co-pressing. In the first case, filamentary composites with various designs can be produced whereas in the second case sandwich structures are obtained. The experimental window (temperature, time) in which processing can be carried out is directly related to the crystallisation resistance of the glass which requires getting information about the crystallisation conditions in the selected metallic glasses. Thermoforming windows are identified for the studied BMGs by thermal analysis and compression tests in their SLR. The mechanical properties of the produced multi materials are investigated thanks to specifically developed mechanical devices and the interfaces between the amorphous and the crystalline alloys are characterised.

  2. Preparation of Ti-based amorphous brazing alloy

    Institute of Scientific and Technical Information of China (English)

    ZOU Jia-sheng; JIANG Zhi-guo; XU Zhi-rong; CHEN Guang

    2006-01-01

    A new kind of amorphous active brazing alloy foil with the composition of Ti40Zr25Ni15Cu20 was successfully synthesized using melt spinning in roll forging machine in argon atmosphere. The amorphous structure and composition were examined by X-ray diffraction, differential thermal analysis and energy dispersive X-ray detector. The results show that the Ti40Zr25Ni15Cu20 amorphous alloy foil has excellent wettability on Si3N4 ceramic and demonstrate a strong glass forming ability. The reduced glass transition temperature (Trg) and the temperature interval of supercooled liquid region before crystallization are 0.76 and 78 K, respectively.

  3. Cracking susceptibility of aluminum alloys during laser welding

    Directory of Open Access Journals (Sweden)

    Lara Abbaschian

    2003-06-01

    Full Text Available The influence of laser parameters in welding aluminum alloys was studied in order to reduce hot cracking. The extension of cracks at the welding surface was used as a cracking susceptibility (CS index. It has been shown that the CS changes with changing welding velocity for binary Al-Cu alloys. In general, the CS index increased until a maximum velocity and then dropped to zero, generating a typical lambda-curve. This curve is due to two different mechanisms: 1 the refinement of porosities with increasing velocity and 2 the changes in the liquid fraction due to decreasing microsegregation with increasing velocities.

  4. Control of Surface Attack by Gallium Alloys in Electrical Contacts.

    Science.gov (United States)

    1986-03-28

    and atmospheric control but does not allow visual observation of the contact brushes. This machine is a small homopolar motor built from mild steel...collectors,gallium, homopolar devices,liquid metals,~- is. ABSTRACT ICNI.. .. w 41N"w -~dv.mp.d Wrllt by Itabata" * Electrical contact between a copp’er...32 5 Test rig with felt metal brushes 32 6 Homopolar test apparatus 33 7 Rewetting of alloy track 33 8 Alloy track after running with finger 34 brushes

  5. Phase transformations and microstructure development in low alloy steel welds

    Energy Technology Data Exchange (ETDEWEB)

    Babu, S.S.; David, S.A.; Vitek, J.M. [and others

    1995-07-01

    Microstructure development in low alloy steel welds depends on various phase transformations that are a function of weld heating and cooling. The phase changes include non-metallic oxide inclusion formation in the liquid state, weld pool solidification, and solid state transformations. In this paper the mechanism of inclusion formation during low alloy steel welding is considered and the model predictions are compared with published results. The effect of inclusions on the austenite to ferrite transformation kinetics is measured and the mechanisms of transformation are discussed. The austenite gain development is related to the driving force for transformation of {delta} ferrite to austenite.

  6. Mg Alloy Foam Fabrication via Melt Foaming Method

    Institute of Scientific and Technical Information of China (English)

    Donghui YANC; Changhwan SEO; Bo-Young HUR

    2008-01-01

    For the first time AZ91 (MgAl9Zn1) and AM60 (MgAl6) Mg alloy foams with homogeneous pore structures were prepared successfully via melt foaming method using CaCO3 as blowing agent. It is revealed that the blowing gas to foam the melt is not CO2 but CO, which comes from liquid-solid reaction between Mg melt. The reaction temperature is more than 100℃ lower than CaCO3 decomposition, which makes Mg alloy melts foam into cellular structure much more easily in the temperature range from 690℃ to 750℃.

  7. Sample preparation of metal alloys by electric discharge machining

    Science.gov (United States)

    Chapman, G. B., II; Gordon, W. A.

    1976-01-01

    Electric discharge machining was investigated as a noncontaminating method of comminuting alloys for subsequent chemical analysis. Particulate dispersions in water were produced from bulk alloys at a rate of about 5 mg/min by using a commercially available machining instrument. The utility of this approach was demonstrated by results obtained when acidified dispersions were substituted for true acid solutions in an established spectrochemical method. The analysis results were not significantly different for the two sample forms. Particle size measurements and preliminary results from other spectrochemical methods which require direct aspiration of liquid into flame or plasma sources are reported.

  8. Correlation of recalescence with grain refinement of magnesium alloys

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The grain refinement of Mg-Al based alloys with carbon inoculation was investigated by a computer-aided cooling curve analysis(CA-CCA)system.The results show that carbon inoculation decreases the main parameters of the recalescence regime during the initial stage of solidification.These parameters include the recalescence undercooling(△θrec),duration of recalescence (trec),and liquid peak parameter(LPP)which is firstly introduced into magnesium alloys.The resultant grain size decreases with increasing nucleation temperature(θn)and decreasing values of △θrec,trec and LPE

  9. The effects of microstructure on crack initiation in liquid-metal environments

    CSIR Research Space (South Africa)

    Fernandes, PJL

    1997-09-01

    Full Text Available Liquid-metal-induced embrittlement under tensile test conditions is identified by the existence of a characteristic ductility trough. In this study, the effect of molten gallium on the behaviour of two brass alloys with different microstructures...

  10. Numerical Simulation for Filling Process of Aluminum Alloy in Semi-Solid Diecasting and Liquid Diecasting%铝合金半固态压铸与液态压铸充型过程的模拟

    Institute of Scientific and Technical Information of China (English)

    史立峰; 赵大志; 王平; 崔建忠

    2012-01-01

    利用AnyCasting软件模拟了ZL201合金半固态压铸和液态压铸充型的流动过程,并进行了试验验证.模拟及试验结果显示:合理的控制速度转换位置,能够保证半固态浆料以层流方式充填型腔,获得平缓的充型过程,有利于避免卷气、氧化夹杂等缺陷的产生.在相同的速度条件下进行液态压铸,金属液以湍流方式充填型腔,容易形成喷溅和卷气的现象.模拟结果与试验相符合.%The flow characteristics of semi-solid filling and liquid filling were compared and analyzed by using the AnyCasting software. The experiment was conducted to validate the simulated results. The results indicate that if speed switch section is reasonable, the semi-solid slurry fill the cavity by way of laminar flow which can reduce the foundry defects such as gas cavity and oxide inclusion. However, under the same speed conditions, the liquid filling is characteristic of turbulent flow, and air entrapment and sputtering easily occur. The simulation results are well in agreement with experimental ones.

  11. Some Issues in Liquid Metals Research

    Directory of Open Access Journals (Sweden)

    Maria José Caturla

    2015-11-01

    Full Text Available The ten articles [1–10] included in this Special Issue on “Liquid Metals” do not intend to comprehensively cover this extensive field, but, rather, to highlight recent discoveries that have greatly broadened the scope of technological applications of these materials. Improvements in understanding the physics of liquid metals are, to a large extent, due to the powerful theoretical tools in the hands of scientists, either semi-empirical [1,5,6] or ab initio (molecular dynamics, see [7]. Surface tension and wetting at metal/ceramic interfaces is an everlasting field of fundamental research with important technological implications. The review of [2] is broad enough, as the work carried out at Grenoble covers almost all interesting matters in the field. Some issues of interest in geophysics and astrophysics are discussed in [3]. The recently discovered liquid–liquid transition in several metals is dealt with in [4]. The fifth contribution [5] discusses the role of icosahedral superclusters in crystallization. In [6], thermodynamic calculations are carried out to identify the regions of the ternary phase diagram of Al-Cu-Y, where the formation of amorphous alloys is most probable. Experimental data and ab initio calculations are presented in [7] to show that an optimal microstructure is obtained if Mg is added to the Al-Si melt before than the modifier AlP alloy. Shock-induced melting of metals by means of laser driven compression is discussed in [8]. With respect to recent discoveries, one of the most outstanding developments is that of gallium alloys that are liquid at room temperature [9], and that, due to the oxide layer that readily cover their surface, maintain some “stiffness”. This has opened the possibility of 3D printing with liquid metals. The last article in this Special Issue [10] describes nano-liquid metals, a suspension of liquid metal and its alloy containing nanometer-sized particles. A room-temperature nano-liquid metal

  12. Chinese Tritium Technology of the Liquid Lithium-lead Alloy Experimental Loop for ITER%ITER中国液态锂铅实验回路中的氚技术

    Institute of Scientific and Technical Information of China (English)

    谢波; 吴宜灿; 翁葵平; 杨通在; 刘云怒; 宋勇; FDS团队

    2011-01-01

    The multinational cooperation in the International Thermonuclear Experimental Reactor (ITER) plan aims to show that fusion reactors are a new and viable way to address global energy concerns.The Chinese Dual Function Lithium Lead Testing Blanket Module (DFLL-TBM) is one of the major research programs and uses liquid lithium-lead as both breeder and cooler, and a helium-hydrogen gas bubbling method is used to extract tritium.So, tritium technology is a key issue in the liquid metal blanket.Based on the development strategy for Chinese liquid lithium-lead experimental blanket technology, development of Chinese tritium technology for liquid lithiumlead loops between 2004 and 2010 was elaberated in three fields, namely, theoretical analysis and calculation, experimental research, and engineering design.Some important information were introduced, such as the simulation-design-develop of liquid lithium-lead bubbler,tritium analysis and permeation barriers in the loops, tritium release from lithium-lead after irradiation, design of tritium extraction system for the blanket, etc.These works indicate that it is possible to completely overcome the difficulties involving very small solubility of tritium in the lithium-lead, accumulation of Magneto-Hydro-Dynamics (MHD) after a long period of continuous operation, materials corrosion together with the pressure drop caused by wall stress, and many technical problems, such as tritium retention, penetration,recovery and environment pollution, can be thoroughly solved.%多方合作的国际热核实验堆(ITER)计划是全球能源问题关注的一个重要进展标志,中国参与提出的双功能液态锂铅包层模块(DFLL-TBM)是一重要组成部分,采用液态锂铅合金作为氚增殖剂和冷却剂,氢-氦混合气鼓泡方式提取氚.因此,氚技术成为关系液态金属包层成败的关键问题之一.结合中国液态锂铅实验包层技术的发展战略,从理论分析与计算

  13. Modification Mechanism of Rare Earth Elements in ZA27 Casting Alloys

    Institute of Scientific and Technical Information of China (English)

    刘贵立; 李荣德

    2003-01-01

    The model of the liquid-phase ZA27 alloys was set up by molecular dynamics theory. The atomic structure of phase, RE-compounds, and the phase-liquid interface in ZA27 alloys were constructed by computer programming. Electronic structures of phase with rare earth elements dissolved and of phase-liquid interfaces with rare earth elements enrichment in ZA27 casting alloys were investigated by using the Recursion method. The ESE energy of RE elements and the structure energy of RE-compounds, phase, and the liquid-phase ZA27 alloys were calculated. The results show that rare earth elements are more stable to be in the phase interface than in phase, which explains the fact of very small solid so lubility of rare earth elements in phase, and the enrichment in the solid-liquid growth front. This makes dendrite melt and break down, dissociate and propagate. RE-compounds can act as heterogeneous nuclei for phase, leading to phase refinement. All above elucidates the modification mechanism of rare earth elements in zinc-aluminum casting alloys at electronic level.

  14. Pressure Induced Liquid-to-Liquid Transition in Zr-based Supercooled Melts and Pressure Quenched Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Dmowski, W.; Gierlotka, S.; Wang, Z.; Yokoyama, Y.; Palosz, B.; Egami, T.

    2017-07-26

    Through high-energy x-ray diffraction and atomic pair density function analysis we find that Zr-based metallic alloy, heated to the supercooled liquid state under hydrostatic pressure and then quenched to room temperature, exhibits a distinct glassy structure. The PDF indicates that the Zr-Zr distances in this glass are significantly reduced compared to those quenched without pressure. Annealing at the glass transition temperature at ambient pressure reverses structural changes and the initial glassy state is recovered. This result suggests that pressure causes a liquid-to-liquid phase transition in this metallic alloy supercooled melt. Such a pressure induced transition is known for covalent liquids, but has not been observed for metallic liquids. The High Pressure Quenched glasses are stable in ambient conditions after decompression.

  15. Correlation between diffusion barriers and alloying energy in binary alloys

    DEFF Research Database (Denmark)

    Vej-Hansen, Ulrik Grønbjerg; Rossmeisl, Jan; Stephens, Ifan;

    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....

  16. Numerical modelling of the binary alloys solidification with solutal undercooling

    Directory of Open Access Journals (Sweden)

    T. Skrzypczak

    2008-03-01

    Full Text Available In thc papcr descrip~ion of mathcmn~icaI and numerical modcl of binay alloy sot idification is prcscntcd. Mctal alloy consisting of maincomponent and solulc is introduced. Moving, sharp solidification rmnt is assumcd. Conaitulional undcrcooling phcnomcnon is tnkcn intoconsidcralion. As a solidifica~ionf ront advances, solutc is rcdistributcd at thc intcrfacc. Commonly, solutc is rejccted into Itlc liquid. whcrcit accumuIatcs into solittc boundary laycr. Depending on thc tcmpcrature gradient, such tiquid may be undcrcoolcd hclow its mclting point,cvcn though it is hot~crth an liquid at thc Front. This phcnomcnon is orten callcd constitutional or soIr~talu ndcrcool ing, to cmphasizc that itariscs from variations in solutal distribution or I iquid. An important conscqucncc of this accurnulntion of saIutc is that it can cause thc frontto brcak down into cclls or dendri~csT. his occurs bccausc thcrc is a liquid ahcad of thc front with lowcr solutc contcnt, and hcncc a highcrme1 ting tcmpcraturcs than liquid at thc front. In rhc papcr locarion and shapc of wndcrcoolcd rcgion dcpcnding on solidification pararnctcrsis discussed. Nurncrical mcthod basing on Fini tc Elelncnt Mctbod (FEM allowi~lgp rcdiction of breakdown of inoving planar front duringsolidification or binary alloy is proposed.

  17. Subsidizing Liquidity

    DEFF Research Database (Denmark)

    Malinova, Katya; Park, Andreas

    2015-01-01

    Facing increased competition over the last decade, many stock exchanges changed their trading fees to maker-taker pricing, an incentive scheme that rewards liquidity suppliers and charges liquidity demanders. Using a change in trading fees on the Toronto Stock Exchange, we study whether and why...

  18. Liquid pearls

    CERN Document Server

    Bremond, Nicolas; Bibette, Jérôme

    2010-01-01

    This fluid dynamics video reports how to form liquid core capsules having a thin hydrogel elastic membrane named liquid pearls. These fish-egg like structures are initially made of a millimetric liquid drop, aqueous or not, coated with an aqueous liquid film containing sodium alginate that gels once the double drop enters a calcium chloride bath. The creation of such pearls with micrometer thick membrane requires to suppress mixing until gelling takes place. Here, we show that superimposing a two dimensional surfactant precipitation at the interface confers a transient rigidity that can damp the shear induced instability at impact. Based on this, pearls containing almost any type of liquids can be created. The video focuses on the dynamics of the entry of the compound drop into the gelling bath.

  19. Impact toughness of laser alloyed aluminium AA1200 alloys

    CSIR Research Space (South Africa)

    Mabhali, Luyolo AB

    2013-08-01

    Full Text Available Laser surface alloying of aluminium AA1200 was performed with a 4kW Nd:YAG laser and impact resistance of the alloys was investigated. The alloying powders were a mixture of Ni, Ti and SiC in different proportions. Surfaces reinforced...

  20. Microstructure and corrosion resistance of AlCrFeCuCo high entropy alloy

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Xing-Wu, E-mail: qiuxingwu@126.com [School of Material Science and Engineering, Xi' an University of Technology, Xi' an 710048 (China); Department of Materials Engineering, Sichuan College of Architectural Technology, Deyang 618000 (China); Zhang, Yun-Peng; He, Li [School of Material Science and Engineering, Xi' an University of Technology, Xi' an 710048 (China); Liu, Chun-ge [Department of Transportation and Municipal Engineering, Sichuan College of Architectural Technology, Deyang 618000 (China)

    2013-02-05

    Highlights: Black-Right-Pointing-Pointer We use a new method (laser cladding) to prepare high-entropy alloy. Black-Right-Pointing-Pointer We gained small microstructure under rapid solidification condition. Black-Right-Pointing-Pointer We studied corrosion resistance of AlCrFeCuCo high-entropy alloy in two different liquids. - Abstract: The AlCrFeCuCo high-entropy alloys were prepared by the laser cladding method. The microstructure and corrosion resistance property of AlCrFeCuCo high-entropy alloy were researched by scanning electron microscopy, X-ray diffraction and electrochemical workstation. The results show that, under the rapid solidification small microstructure gained, the morphology of AlCrFeCuCo high entropy alloy is simple, the phase mainly compose of FCC and BCC; elements segregated in the alloys; the alloy shows excellent corrosion resistance, along with the increase of the scanning speed, alloy corrosion resistance performance shows a enhancement in the first and then weakened trend. The corrosion resistance performance of AlCrFeCuCo high-entropy alloys in 1 mol/L NaCl solution is better than in 0.5 mol/L H{sub 2}SO{sub 4} solution.

  1. 用铜锌中间层瞬时液相连接Al 2024和Ti-6Al-4V合金%Transient liquid phase bonding of Al 2024 to Ti-6Al-4V alloy using Cu-Zn interlayer

    Institute of Scientific and Technical Information of China (English)

    Majid SAMAVATIAN; Ayoub HALVAEE; Ahmad Ali AMADEH; Alireza KHODABANDEH

    2015-01-01

    采用Cu−22%Zn中间层,在510°C、真空度为0.01 Pa和不同连接时间下将两种异质合金Al 2024和Ti−6Al−4V进行瞬时液相连接。采用SEM、EDS和XRD技术对连接区的显微组织演变进行表征。结果表明,接头的形成归因于Cu和Zn固相扩散进入Ti−6Al−4V和Al 2024合金中,然后形成共晶并沿Cu−Zn/Al 2024界面等温扩散。接头界面处的硬度随连接时间的延长而增加,这是由于形成了Al2Cu、TiCu3、Al4.2Cu3.2Zn0.7、Al0.71Zn0.29、Ti2Cu、TiAl3和TiZn16金属间合物。此外,当连接时间为60 min时,接头的剪切强度达到最大,为37 MPa。%Transient liquid phase bonding of two dissimilar alloys Al 2024 and Ti−6Al−4V using Cu−22%Zn interlayer was carried out at 510 °C under vacuum of 0.01 Pa for various bonding time. In order to characterize the microstructure evolution in the joint zone, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) were applied. The results show that joint formation is attributed to the solid-state diffusion of Cu and Zn into Ti−6Al−4V and Al 2024 alloys followed by eutectic formation and isothermal solidification along the Cu−Zn/Al 2024 interface. The hardness of the joints at the interface increases with an increase in bonding time which can be attributed to formation of intermetallic compounds such as Al2Cu, TiCu3, Al4.2Cu3.2Zn0.7, Al0.71Zn0.29, Ti2Cu, TiAl3 and TiZn16 in the joint zone. Moreover, shear strength of the joint reaches the highest value of 37 MPa at bonding time of 60 min.

  2. Simulation of formation and evolution of nano-clusters during rapid solidification of liquid Ca70Mg30 alloy%液态Ca70Mg30合金快速凝固过程中纳米团簇结构形成演变特性模拟

    Institute of Scientific and Technical Information of China (English)

    周丽丽; 刘让苏; 田泽安

    2013-01-01

    A molecular dynamics simulation study was performed to investigate the formation and evolution mechanisms of nano-clusters during the rapid solidification of liquid Ca70Mg30 alloy. The cluster-type index method (CTIM) was adopted to describe microstructure evolutions of nano-clusters during solidification. Results indicate that amorphous structure is mainly formed with three bond-types of 1551, 1541 and 1431 at the cooling rate of 5×1011 K/s, and glass transition temperature Tg is about 530 K;the icosahedron cluster of (12 0 12 0) plays a key role in formation of amorphous structure, and smaller Mg atoms are much more probable to be central atoms of icosahedron clusters; and nano-clusters are mainly formed by combining medium-size clusters. Interestingly, it was also found that formation and evolution processes of the nano-cluster display a three-stage feature which is analogous to crystallization process of amorphous alloy.%采用分子动力学方法对液态Ca70Mg30合金快速凝固过程中纳米团簇结构的形成和演变特性进行模拟。采用原子团类型指数法(CTIM)对凝固过程中纳米团簇结构的演变进行分析。结果表明:系统在5×1011 K/s的冷速条件下形成以1551、1541和1431为主的非晶态结构,非晶转变温度约为530 K;(120120)二十面体基本原子团对系统非晶结构的形成起到决定性的作用,并且原子半径较小的Mg原子更容易占据二十面体基本原子团中心原子的位置;同时,纳米团簇主要是通过中等尺寸团簇的合并而形成,纳米级大团簇的形成演变过程呈现出类似于非晶晶化过程的3个阶段式的变化。

  3. 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.

  4. Selective dissolution in binary alloys

    Science.gov (United States)

    McCall, Carol Rene

    Corrosion is an important issue in the design of engineering alloys. De-alloying is an aspect of alloy corrosion related to the selective dissolution of one or more of the components in an alloy. The work reported herein focuses on the topic of de-alloying specific to single-phase binary noble metal alloy systems. The alloy systems investigated were gold-silver and gold-copper. The onset of a bulk selective dissolution process is typically marked by a critical potential whereby the more reactive component in the alloy begins dissolving from the bulk, leading to the formation of a bi-continuous solid-void morphology. The critical potential was investigated for the entire composition range of gold-silver alloys. The results presented herein include the formulation of an expression for critical potential as a function of both alloy and electrolyte composition. Results of the first investigation of underpotential deposition (UPD) on alloys are also presented herein. These results were implemented as an analytical tool to provide quantitative measurements of the surface evolution of gold during de-alloying. The region below the critical potential was investigated in terms of the compositional evolution of the alloy surface. Below the critical potential, there is a competition between the dissolution of the more reactive alloying constituent (either silver or copper) and surface diffusion of gold that serves to cover dissolution sites and prevent bulk dissolution. By holding the potential at a prescribed value below the critical potential, a time-dependent gold enrichment occurs on the alloy surface leading to passivation. A theoretical model was developed to predict the surface enrichment of gold based on the assumption of layer-by-layer dissolution of the more reactive alloy constituent. The UPD measurements were used to measure the time-dependent surface gold concentration and the results agreed with the predictions of the theoretical model.

  5. Modelling temperature and concentration dependent solid/liquid interfacial energies

    Science.gov (United States)

    Lippmann, Stephanie; Jung, In-Ho; Paliwal, Manas; Rettenmayr, Markus

    2016-01-01

    Models for the prediction of the solid/liquid interfacial energy in pure substances and binary alloys, respectively, are reviewed and extended regarding the temperature and concentration dependence of the required thermodynamic entities. A CALPHAD-type thermodynamic database is used to introduce temperature and concentration dependent melting enthalpies and entropies for multicomponent alloys in the temperature range between liquidus and solidus. Several suitable models are extended and employed to calculate the temperature and concentration dependent interfacial energy for Al-FCC with their respective liquids and compared with experimental data.

  6. 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...

  7. Choice of salts for process of continous sodium modification of Al-Si alloys

    Directory of Open Access Journals (Sweden)

    Białobrzeski A.

    2007-01-01

    Full Text Available Broad application of aluminum cast alloys, silumins first of all, have become to be possible after finding a method of change of solidification form in Al-Si eutectic mixture. By introduction to liquid alloy a slight additive of modifying agent this primary thick, needle-like shape of Si crystals becomes altered into fine and compact structure. Quality of structure modification depends on correct proportioning of the modifying agent, temperature of metal and time elapsing from modification to solidification of the alloy. The sodium is used as one of the modifying agents. The sodium is introduced into metal bath in metallic form or in form of compounds containing sodium. Apart from a form in which modifying agent is introduced to metal bath, however, its action is relatively short (about 15-20 minutes. Prolongation of modifying agent’s action can be accomplished due to technology of continuous introduction of the sodium to metal bath. That technology is based on continuous electrolysis of sodium salt, occurring directly in melting pot with liquid alloy. Sodium salt placed in retort ( immersed in liquid metal undergoes dissociation due to applied voltage, and next electrolysis. Sodium ions arisen during the dissociation of sodium salts and electrolysis are “conveyed” through retort walls made from solid electrolyte. In contact with liquid alloy as cathode, sodium ions pass to atomic state, modifying the alloy. Suitable selection of material for the anode (source of sodium is an important issue. The paper presents results of preliminary research concerning selection of sodium salt, based on predetermined Rm tensile strength and measured voltage drop for the alloy in solid state. Values of those parameters confirm modification effect on tested alloys. Complexity of physical-chemical phenomena occurring in course of the process effects on necessity of further investigation which needs to be performed for optimization of parameters of the

  8. Microstructure and properties of vacuum counter-pressure cast aluminum alloy

    OpenAIRE

    YAN Qing-song; Yu, Huan; WEI Bo-kang

    2006-01-01

    The microstructure and properties of vacuum counter-pressure cast aluminum alloy were studied. Results indicated that under the condition of vacuum counter-pressure, liquid melts fill mould cavity under the vacuum and crystallize under high pressure which have very good effect on nucleation and solidification feeding. Compared with gravity casting, the microstructure of vacuum counter-pressure cast aluminum alloy is much finer and more uniformly distributed. Mechanical properties of vacuum co...

  9. Preparation of Al-Sr Master Alloy in Aluminum Electrolysis Cell

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Al-Sr master alloy was prepared by using liquid aluminum cathode and a mixture of Na3AlF6- SrCO3 as the basic molten salt electrolyte in a laboratory electrolysis cell.The effects of electrolyte composition,electrolysis temperature,cathodic current density and the electrolytic duration on Sr content of Al-Sr alloy were studied.Through laboratory experiments,the parameters for smooth electrolytic reaction were proposed.

  10. In-situ observation of porosity formation during directional solidification of Al-Si casting alloys

    Directory of Open Access Journals (Sweden)

    Zhao Lei

    2011-02-01

    Full Text Available In-situ observation of porosity formation during directional solidification of two Al-Si alloys (7%Si and 13%Si was made by using of micro-focus X-ray imaging. In both alloys, small spherical pores initially form in the melt far away from the eutectic solid-liquid (S/L interface and then grow and coagulate during solidification. Some pores can float and escape from the solidifying melt front at a relatively high velocity. At the end of solidification, the remaining pores maintain spherical morphology in the near eutectic alloy but become irregular in the hypoeutectic alloy. This is attributed to different solidification modes and aluminum dendrite interactions between the two alloys. The mechanism of the porosity formation is briefly discussed in this paper.

  11. Surface alloying of Cu with Ti by double glow discharge process

    Institute of Scientific and Technical Information of China (English)

    袁庆龙; 池成忠; 苏永安; 徐重; 唐宾

    2004-01-01

    The surface of pure copper alloyed with Ti using double glow discharge process was investigated. The morphology, structure and forming mechanism of the Cu-Ti alloying layer were analyzed. The microhardness and wear resistance of the Cu-Ti alloying layer were measured, and compared with those of pure copper. The results indicate that the surface of copper activated by Ar and Ti ions bombardment is favorable to absorption and diffusion of Ti element. In current experimental temperature, as the Ti content increases, the liquid phase occurs between the deposited layer and diffused layer, which makes the Ti ions and atoms easy to dissolve and the thickness of Cu-Ti alloying layer increase rapidly. After cooling, the structure of the alloying layer is composed of CuTi, Cu4 Ti and Cu(Ti) solid solution. The solid solution strengthening and precipitation strengthening effects of Ti result in high surface hardness and wear resistance.

  12. Influence of Ultrasound Treatment on Cavitation Erosion Resistance of AlSi7 Alloy

    Directory of Open Access Journals (Sweden)

    Annalisa Pola

    2017-03-01

    Full Text Available Ultrasound treatment of liquid aluminum alloys is known to improve mechanical properties of castings. Aluminum foundry alloys are frequently used for production of parts that undergo severe cavitation erosion phenomena during service. In this paper, the effect of the ultrasound treatment on cavitation erosion resistance of AlSi7 alloy was assessed and compared to that of conventionally cast samples. Cavitation erosion tests were performed according to ASTM G32 standard on as-cast and heat treated castings. The response of the alloy in each condition was investigated by measuring the mass loss as a function of cavitation time and by analyzing the damaged surfaces by means of optical and scanning electron microscope. It was pointed out that the ultrasound treatment increases the cavitation erosion resistance of the alloy, as a consequence of the higher chemical and microstructural homogeneity, the finer grains and primary particles and the refined structure of the eutectic induced by the treatment itself.

  13. De-alloyed platinum nanoparticles

    Science.gov (United States)

    Strasser, Peter [Houston, TX; Koh, Shirlaine [Houston, TX; Mani, Prasanna [Houston, TX; Ratndeep, Srivastava [Houston, TX

    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.

  14. Extreme solid state refrigeration using nanostructured Bi-Te alloys.

    Energy Technology Data Exchange (ETDEWEB)

    Lima Sharma, Ana L. (San Jose State University, San Jose, CA); Spataru, Dan Catalin; Medlin, Douglas L.; Sharma, Peter Anand; Morales, Alfredo Martin

    2009-09-01

    Materials are desperately needed for cryogenic solid state refrigeration. We have investigated nanostructured Bi-Te alloys for their potential use in Ettingshausen refrigeration to liquid nitrogen temperatures. These alloys form alternating layers of Bi{sub 2} and Bi{sub 2}Te{sub 3} blocks in equilibrium. The composition Bi{sub 4}Te{sub 3} was identified as having the greatest potential for having a high Ettingshausen figure of merit. Both single crystal and polycrystalline forms of this material were synthesized. After evaluating the Ettingshausen figure of merit for a large, high quality polycrystal, we simulated the limits of practical refrigeration in this material from 200 to 77 K using a simple device model. The band structure was also computed and compared to experiments. We discuss the crystal growth, transport physics, and practical refrigeration potential of Bi-Te alloys.

  15. Corrosion behavior of electrodeposited Co-Fe alloys in aerated solutions

    Science.gov (United States)

    Chansena, A.; Sutthiruangwong, S.

    2017-05-01

    Co-Fe alloy is an important component for reader-writer in hard disk drive. The surface of the alloy is exposed to the environment both in gas phase and in liquid phase during manufacturing process. The study of corrosion behavior of Co-Fe alloys can provide useful fundamental data for reader-writer production planning especially when corrosion becomes a major problem. The corrosion study of electrodeposited Co-Fe alloys from cyclic galvanodynamic polarization was performed using potentiodynamic polarization technique. The composition of electrodeposited Co-Fe alloys was determined by X-ray fluorescence spectrometry. The patterns from X-ray diffractometer showed that the crystal structure of electrodeposited Co-Fe alloys was body-centered cubic. A vibrating sample magnetometer was used for magnetic measurements. The saturation magnetization (Ms) was increased and the intrinsic coercivity (Hci) was decreased with increasing Fe content. The corrosion rate study was performed in aerated deionized water and aerated acidic solutions at pH 3, 4 and 5. The corrosion rate diagram for Co-Fe alloys was constructed. It was found that the corrosion rate of Co-Fe alloys was increased with increasing Fe content in both aerated deionized water and aerated acidic solutions. In aerated pH 3 solution, the Co-Fe alloy containing 78.8% Fe showed the highest corrosion rate of 7.7 mm yr-1 with the highest Ms of 32.0 A m2 kg-1. The corrosion rate of the alloy with 23.8% Fe was at 1.1 mm yr-1 with Ms of 1.2 A m2 kg-1. In aerated deionized water, the alloy with the highest Fe content of 78.5% still showed the highest corrosion rate of 0.0059 mm yr-1 while the alloy with the lowest Fe content of 20.4% gave the lowest corrosion rate of 0.0045 mm yr-1.

  16. Studies of Nucleation and Growth, Specific Heat and Viscosity of Undercooled Melts of Quasicrystals and Polytetrehedral-Phase-Forming Alloys

    Science.gov (United States)

    2003-01-01

    By investigating the properties of quasicrystals and quasicrystal-forming liquid alloys, we may determine the role of ordering of the liquid phase in the formation of quasicrystals, leading to a better fundamental understanding of both the quasicrystal and the liquid. A quasicrystal is solid characterized by a symmetric but non-periodic arrangement of atoms, usually in the form of an icosahedron (12 atoms, 20 triangular faces). It is theorized that the short-range order in liquids takes this same form. The degree of ordering depends on the temperature of the liquid, and affects many of the liquid s properties, including specific heat, viscosity, and electrical resistivity. The MSFC role in this project includes solidification studies, phase diagram determination, and thermophysical property measurements on the liquid quasicrystal-forming alloys, all by electrostatic levitation (ESL). The viscosity of liquid quasicrystal-forming alloys is measured by the oscillating drop method, both in the stable and undercooled liquid state. The specific heat of solid, undercooled liquid, and stable liquid are measured by the radiative cooling rate of the droplets.

  17. Managing liquidity

    DEFF Research Database (Denmark)

    Pokutta, Sebastian; Schmaltz, Christian

    2011-01-01

    Large banking groups face the question of how to optimally allocate and generate liquidity: in a central liquidity hub or in many decentralized branches. We translate this question into a facility location problem under uncertainty. We show that volatility is the key driver behind (de...... above which it is advantageous to open a liquidity center and show that it is a function of the volatility and the characteristic of the bank network. Finally, we discuss the n-branch model for real-world banking groups (10-60 branches) and show that it can be solved with high granularity (100 scenarios...

  18. 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.

  19. Neutron absorbing alloy

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Masayuki

    1998-12-04

    The neutron absorbing alloy of the present invention comprises Ti or an alloy thereof as a mother material, to which from 2 to 40% by weight of Hf and Gd within a range of from 4 to 50% by weight in total are added respectively. Ti is excellent in specific strength, corrosion resistance and workability, and produces no noxious intermetallic compound with Hf and Gd. In addition, since the alloy can incorporate a great quantity of Hf and Gd, a neutron absorbing material having excellent neutron absorbing performance than usual and excellent in specific strength, corrosion resistance and workability can be manufactured conveniently and economically not by a special manufacturing method. (T.M.)

  20. Multistep electrochemical deposition of hierarchical platinum alloy counter electrodes for dye-sensitized solar cells

    Science.gov (United States)

    Zhang, Junjun; Ma, Mingming; Tang, Qunwei; Yu, Liangmin

    2016-01-01

    The preferred platinum counter electrode (CE) has been a burden for commercialization of dye-sensitized solar cell (DSSC) due to high expense and chemical corrosion by liquid electrolyte. In the current study, we have successfully realized the multistep deposition of platinum alloy CEs including PtNi, PtFe, and PtCo for liquid-junction DSSC applications. The preliminary results demonstrate that the enhanced electrochemical activities are attributable to high charge-transfer ability and matching work functions of the PtM (M = Ni, Fe, Co) alloy CEs to redox potential of I-/I3- electrolyte. The resultant DSSCs yield impressive power conversion efficiencies of 8.65%, 7.48%, and 7.08% with PtNi, PtFe, and PtCo CEs, respectively. On behalf of the competitive reactions between transition metals with liquid electrolyte, the PtM alloy CEs display enhanced long-term stability.

  1. 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.

  2. 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.

  3. Method of fabricating thin-walled articles of tungsten-nickel-iron alloy

    Science.gov (United States)

    Hovis, V.M. Jr.; Northcutt, W.G. Jr.

    The present invention relates to a method for fabricating thin-walled high-density structures of tungsten-nickel-iron alloys. A powdered blend of the selected alloy constituents is plasma sprayed onto a mandrel having the desired article configuration. The sprayed deposit is removed from the mandrel and subjected to liquid phase sintering to provide the alloyed structure. The formation of the thin-walled structure by plasma spraying significantly reduces shrinkage, and cracking while increasing physical properties of the structure over that obtainable by employing previously known powder metallurgical procedures.

  4. Semi-solid Processing of Alloys

    Science.gov (United States)

    Kirkwood, David H.; Suéry, Michel; Kapranos, Plato; Atkinson, Helen V.; Young, Kenneth P.

    The original semisolid forming process, developed at MIT in 1972, involved stirring an alloy during solidification to produce a slurry of spheroidal primary particles in a liquid matrix, which was then injected directly into a die to produce a solid component. This was termed "rheocasting." Subsequently, it was found more convenient to solidify the slurry completely during the continuous casting of an electromag netically stirred strand, which was then cut into slugs for partial remelting back into semisolid billets on demand. These could be loaded into a diecasting machine in this state for injection into the die. This alternative process route is called "thixoforming," and until recently, it was the preferred industrial process. For this reason, the microstructure developed during the reheating and melting for thixo forming will be considered first. Experimentally, it has been found that the most effective fraction solid f s for thixoforming, lies between 0.5 and 0.6. Below this range, the semisolid slug becomes too soft to support its own weight and sags during remelting; above this range, it is too stiff to flow readily and fill the die. However, the slurry technologies used in rheocasting typically operate at lower fraction solids and rely on the ability to pour the semisolid alloy much like a liquid (see Chap. 4). It has been observed in practice that the fraction solid is in fact a critical factor for effective thixoforming, and therefore, both good temperature control and lack of sensitivity of f s to small temperature variations of the alloy are essential to efficient manufacturing.

  5. 液态Pb-Cu合金结构与扩散性质的分子动力学模拟%Molecular Dynamics Simulation on Structural and Transport Properties of Binary Liquid Pb-Cu Alloy

    Institute of Scientific and Technical Information of China (English)

    刘媛媛; 贾国斌; 杨斌; 刘大春

    2011-01-01

    通过分子动力学方法模拟液态Pb-Cu合金的熔体结构,得到液态合金的对相关函数曲线、配位数和相关半径,并用于分析合金熔体内部的结构.同时将NRTL方程与分子动力学方法结合,提出一种计算合金互扩散系数的新方法,使用该方法计算得到了Pb-Cu合金的自扩散与互扩散系数,并分析了熔体结构对合金扩散性质的影响.%The structure of binary Pb-Cu liquid was studied using molecular dynamics simulation method. The pair distribution function, coordination number and coordination radius were calculated to analyze the melt structure. By combining the molecular dynamics method and NRTL equation, a new method of computing the mutual diffusion coefficients was obtained. The self and mutual diffusion coefficients of Pb-Cu melt were computed with this method. Moreover the effect of the melt structure on diffusion coefficients was analyzed.

  6. The effect of the interaction between the minority phase droplets on the nucleation behavior during the liquid-liquid phase transformation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The microstructure evolution during the liquid-liquid phase transformation of Al-Pb alloy was calculated. The numerical results indicate that the interaction between the minority phase droplets has effect on the nucleation process of the droplets, and the effect increases with the cooling rate and the content of Pb.

  7. Gravitational Role in Liquid Phase Sintering

    Science.gov (United States)

    Upadhyaya, Anish; Iacocca, Ronald G.; German, Randall M.

    1998-01-01

    To comprehensively understand the gravitational effects on the evolution of both the microstructure and the macrostructure during liquid phase sintering, W-Ni-Fe alloys with W content varying from 35 to 98 wt.% were sintered in microgravity. Compositions that slump during ground-based sintering also distort when sintered under microgravity. In ground-based sintering, low solid content alloys distort with a typical elephant-foot profile, while in microgravity, the compacts tend to spheroidize. This study shows that microstructural segregation occurs in both ground-based as well as microgravity sintering. In ground-based experiments, because of the density difference between the solid and the liquid phase, the solid content increases from top to the bottom of the sample. In microgravity, the solid content increases from periphery to the center of the samples. This study also shows that the pores during microgravity sintering act as a stable phase and attain anomalous shapes.

  8. 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...

  9. Strip Casting of High Performance Structural Alloys

    Institute of Scientific and Technical Information of China (English)

    S S Park; J G Lee; Nack J Kim

    2004-01-01

    There exists a great need for the development of high performance alloys due to increasing demands for energy conservation and environmental protection. Application of strip casting shows a strong potential for the improvement of properties of existing alloys and also for the development of novel alloy systems with superior properties. The present paper reviews our Center's activities in the development of high performance alloys by strip casting. Examples include (1) Al alloys, (2) wrought Mg alloys, and (3) bulk metallic glass (BMG) alloys.

  10. Environmental Durability of Coated GRCop-84 Copper Alloys

    Science.gov (United States)

    Raj, Sai V.; Robinson, C.; Barrett, C.; Humphrey, D.

    2005-01-01

    An advanced Cu-8(at.%)Cr-4%Nb alloy developed at NASA's Glenn Research Center, and designated as GRCop-84, is currently being considered for use as liners in combustor chambers and nozzle ramps in NASA s future generations of reusable launch vehicles (RLVs). However, past experience has shown that unprotected copper alloys undergo an environmental attack called "blanching" in rocket engines using liquid hydrogen as fuel and liquid oxygen as the oxidizer. Potential for sulfidation attack of the liners in hydrocarbon-fueled engines is also of concern. As a result, protective overlay coatings alloys are being developed for GRCop-84. The oxidation behavior of several new coating alloys has been evaluated. GRCop-84 specimens were coated with several copper and nickel-based coatings, where the coatings were deposited by either vacuum plasma spraying or cold spraying techniques. Coated and uncoated specimens were thermally cycled in a furnace at different temperatures in order to evaluate the performance of the coatings. Additional studies were conducted in a high pressure burner rig using a hydrocarbon fuel and subjected to a high heat flux hydrogen-oxygen combustion flame in NASA s Quick Access Rocket Exhaust (QARE) rig. The performance of these coatings are discussed.

  11. Solidification crack susceptibility of aluminum alloy weld metals

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The susceptibilities of the three aluminum alloys to solidification crack were studied with trans-varestraint tests and tensile tests at elevated temperature. Their metallurgical characteristics, morphologies of the fractured surface and dynamic cracking behaviors at elevated temperature were analyzed with a series of micro-analysis methods. The results show that dynamic cracking models can be classified into three types. The first model has the healing effect which is called type A. The second is the one with deformation and breaking down of metal bridge, called type B. The last one is with the separation of liquid film along grain boundary, called type C.Moreover, the strain rate has different effects on crack susceptibility of aluminum alloys with different cracking models. ZL101 and 5083 alloys belong to type A and type C cracking model respectively, in which strain rate has greater effect on eutectic healing and plastic deformation of metal bridge. 6082 alloy is type B cracking model in which the strain rate has little effect on the deformation ability of the liquid film.

  12. Rapid solidification of undercooled Al-Cu-Si eutectic alloys

    Institute of Scientific and Technical Information of China (English)

    RUAN Ying; WEI BingBo

    2009-01-01

    Under the conventional solidification condition,a liquid aluminium alloy can be hardly undercooled because of oxidation.In this work,rapid solidification of an undercooled liquid Al,80.4Cu,13.6Si,6 ternary eutectic alloy was realized by the glass fluxing method combined with recycled superheating.The re-lationship between superheating and undercooling was investigated at a certain cooling rate of the alloy melt.The maximum undercooling is 147 K (0.18 TE).The undercooled ternary eutectic is composed of α(Al) solid solution,(Si) semiconductor and β(CuAl,2) intermetallic compound.In the (Al+Si+θ) ternary eutectic,(Si) faceted phase grows independently,while (Al) and θ non-faceted phases grow coopera-tively in the lamellar mode.When undercooling is small,only (Al) solid solution forms as the leading phase.Once undercooling exceeds 73 K,(Si) phase nucleates firstly and grows as the primary phase.The alloy microstructure consists of primary (Al) dendrite,(Al+9) pseudobinary eutectic and (Al+Si+θ) ternary eutectic at small undercooling,while at large undercooling primary (Si) block,(Al+θ) pseudo-binary eutectic and (Al+Si+θ) ternary eutectic coexist.As undercooling increases,the volume fraction of primary (Al) dendrite decreases and that of primary (Si) block increases.

  13. Experimental Investigation of Ternary Alloys for Fusion Breeding Blankets

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-26

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

  14. Liquid explosives

    CERN Document Server

    Liu, Jiping

    2015-01-01

    The book drawing on the author's nearly half a century of energetic materials research experience intends to systematically review the global researches on liquid explosives. The book focuses on the study of the conception, explosion mechanism, properties and preparation of liquid explosives. It provides a combination of theoretical knowledge and practical examples in a reader-friendly style. The book is likely to be interest of university researchers and graduate students in the fields of energetic materials, blasting engineering and mining.

  15. Ab-initio Simulations of Molten Ni Alloys

    Science.gov (United States)

    2010-04-01

    Mukai’s experimental measurements using the (modified) sessile drop method and (modified) py- 12 cnometric method place β in the range of 2.0 × 10...optimization of the site specific proper- ties of a component. The balance of material and component properties could then take advantage of variations...several other re- cent measurements of liquid Ni alloy densities. Using a sesslie drop method Feng and co-workers measured the density of elemental Ni and

  16. Nanomaterial Synthesis Using Plasma Generation in Liquid

    Directory of Open Access Journals (Sweden)

    Genki Saito

    2015-01-01

    Full Text Available Over the past few decades, the research field of nanomaterials (NMs has developed rapidly because of the unique electrical, optical, magnetic, and catalytic properties of these materials. Among the various methods available today for NM synthesis, techniques for plasma generation in liquid are relatively new. Various types of plasma such as arc discharge and glow discharge can be applied to produce metal, alloy, oxide, inorganic, carbonaceous, and composite NMs. Many experimental setups have been reported, in which various parameters such as the liquid, electrode material, electrode configuration, and electric power source are varied. By examining the various electrode configurations and power sources available in the literature, this review classifies all available plasma in liquid setups into four main groups: (i gas discharge between an electrode and the electrolyte surface, (ii direct discharge between two electrodes, (iii contact discharge between an electrode and the surface of surrounding electrolyte, and (iv radio frequency and microwave plasma in liquid. After discussion of the techniques, NMs of metal, alloy, oxide, silicon, carbon, and composite produced by techniques for plasma generation in liquid are presented, where the source materials, reaction media, and electrode configurations are discussed in detail.

  17. Glass Formation in Ni-Zr-(Al Alloy Systems

    Directory of Open Access Journals (Sweden)

    Lanping Huang

    2013-01-01

    Full Text Available Structural and thermal properties of binary Ni100-xZrx (30alloys obtained by melt spinning and copper mold casting methods were investigated. The fully amorphous samples in a bulk form cannot be obtained in the binary Ni-Zr alloys over a wide composition range, though they have Tg/Tl and γ values close to or even higher than those of the binary Cu-Zr bulk metallic glasses (BMGs. The low thermal stability of the supercooled liquid against crystallization and the formation of the equilibrium crystalline phases with a high growth rate are responsible for their low glass-forming abilities (GFAs. Relatively low thermal conductivities of Ni-based alloys are also considered to be another factor to limit their GFAs. The GFA of the binary Ni65.5Zr34.5 alloy alloyed with 4% or 5% Al was enhanced, and a fully glassy rod with a diameter of 0.5 mm was formed.

  18. Inhibited Aluminization of an ODS FeCr Alloy

    Energy Technology Data Exchange (ETDEWEB)

    Vande Put Ep Rouaix, Aurelie [ORNL; Pint, Bruce A [ORNL

    2012-01-01

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

  19. Formation of austenite in peritectic Fe-C-X alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kalinushkin, E.P.; Sitalo, J. [State Metall. Acad. of Ukraine, Dnepropetrovsk (Ukraine); Fras, E.; Kapturkiewicz, W.; Burbelko, A.A. [Akademia Gorniczo-Hutnicza, Cracow (Poland)

    2000-07-01

    The mechanism for the formation of peritectic austenite in ferrous alloys was examined. The basic role, played by the mechanisms, is well known in technical literature; like diffusion transport through the solid phase which forms an envelope of austenite (peritectic transformation) and a mechanism of transport through channels of liquid in the envelope of austenite (peritectic reaction). Our calculations show that the peritectic transformation prevails at the initial stage of the grain growth, but afterwards the leading role is taken over by the transport through the channels of liquid. Images of the microstructure support the calculations and transport mechanism. (orig.)

  20. Pareto-optimal alloys

    DEFF Research Database (Denmark)

    Bligaard, Thomas; Johannesson, Gisli Holmar; Ruban, Andrei;

    2003-01-01

    and the 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...