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Sample records for ternary nitinol alloys

  1. Hardness and Microstructure of Binary and Ternary Nitinol Compounds

    Science.gov (United States)

    Stanford, Malcolm K.

    2016-01-01

    The hardness and microstructure of twenty-six binary and ternary Nitinol (nickel titanium, nickel titanium hafnium, nickel titanium zirconium and nickel titanium tantalum) compounds were studied. A small (50g) ingot of each compound was produced by vacuum arc remelting. Each ingot was homogenized in vacuum for 48 hr followed by furnace cooling. Specimens from the ingots were then heat treated at 800, 900, 1000 or 1100 degree C for 2 hr followed by water quenching. The hardness and microstructure of each specimen was compared to the baseline material (55-Nitinol, 55 at.% nickel - 45 at.% titanium, after heat treatment at 900 degC). The results show that eleven of the studied compounds had higher hardness values than the baseline material. Moreover, twelve of the studied compounds had measured hardness values greater 600HV at heat treatments from 800 to 900 degree C.

  2. Cavitation Erosion of Electro Spark Deposited Nitinol vs. Stellite Alloy on Stainless Steel Substrate

    Science.gov (United States)

    2015-07-15

    Printed on recycled paper Approved for public release; distribution is unlimited. TECHNICAL REPORT TR-NAVFAC-EXWC-CI-1603 JULY 2015 CAVITATION ...SUBTITLE 5a. CONTRACT NUMBER CAVITATION EROSION TESTING OF ELECTRO SPARK DEPOSITED NITINOL VS STELLITE® ALLOY ON STAINLESS STEEL SUBTRATE 5b. GRANT...of combining Nitinol (NiTi) superelastic metal alloy with ElectroSpark Deposition (ESD) technology to increase the cavitation erosion resistance of

  3. Ternary alloy nanocatalysts for hydrogen evolution reaction

    Indian Academy of Sciences (India)

    Cu–Fe–Ni ternary alloys (size ∼55–80 nm) with varying compositions viz. CuFeNi (A1), CuFe2Ni (A2) and CuFeNi2 (A3) were successfully synthesized using microemulsion. It is to be noted that synthesis of nanocrystallineternary alloys with precise composition is a big challenge which can be overcome by choosing an ...

  4. Ternary alloy nanocatalysts for hydrogen evolution reaction

    Indian Academy of Sciences (India)

    Ternary alloy nanocatalysts for hydrogen evolution reaction. SOUMEN SAHA1, SONALIKA VAIDYA2, KANDALAM V RAMANUJACHARY3,. SAMUEL E LOFLAND4 and ASHOK K GANGULI1,2,∗. 1Department of Chemistry, Indian Institute of Technology, Hauz Khas, New Delhi 110016, India. 2Institute of Nano Science and ...

  5. Synthesis of ternary nitrides by mechanochemical alloying

    DEFF Research Database (Denmark)

    Jacobsen, C.J.H.; Zhu, J.J.; Lindelov, H.

    2002-01-01

    Ternary metal nitrides ( of general formula MxM'N-y(z)) attract considerable interest because of their special mechanical, electrical, magnetic, and catalytic properties. Usually they are prepared by ammonolysis of ternary oxides (MxM'O-y(m)) at elevated temperatures. We show that ternary...... nitrides by mechanochemical alloying of a binary transition metal nitride (MxN) with an elemental transition metal. In this way, we have been able to prepare Fe3Mo3N and Co3Mo3N by ball-milling of Mo2N with Fe and Co, respectively. The transformation sequence from the starting materials ( the binary...... nitride and the transition metal) to the ternary nitride was followed by Mossbauer spectroscopy (for Fe3Mo3N) and by X-ray powder diffraction ( for both Fe3Mo3N and Co3Mo3N). Usually, the preparation of a given ternary nitride by ammonolysis of a ternary oxide is dependent on the availability of an oxide...

  6. A study of phase separation in ternary alloys

    Indian Academy of Sciences (India)

    Keywords. Ternary systems; Cahn–Hilliard equations; spinodal decomposition. Abstract. We have studied the evolution of microstructure when a disordered ternary alloy is quenched into a ternary miscibility gap. We have used computer simulations based on multicomponent Cahn–Hilliard (CH) equations for A and B, ...

  7. Process mechanics and surface integrity of low plasticity burnishing of SE508 nitinol alloy

    Science.gov (United States)

    McKinney, John Ellis, Jr.

    Superelastic Nitinol and shape memory alloys have attracted growing attentions over the recent years in the areas of biomedical and aerospace applications. Surface integrity of Nitinol devices by various fabrication processes is critical for their functionality and performance. Low plasticity burnishing (LPB) is a surface enhancement process to improve surface integrity due to its unique capability to plastically deform material in the deep subsurface on the order of a 500-1000microm. This thesis focuses on the dynamic mechanical behavior of SE508 Nitinol (NiTi) alloy and process mechanics and surface integrity by ball burnishing of the material. The stress-strain behaviors of SE508 NiTi alloy at quasi-static and high strain rates were experimentally determined using a series of compression testing. Then, the experimentally determined stress-strain behavior was used in correlation with Hertzian theory of contact mechanics in ball burnishing of the material. It was found that quasi-static compressive stress-strain behavior correlates well with Hertzian peak pressure. This serves as a basis to select burnishing loads. The effects of LPB parameters, i.e. burnishing pressure, feed, speed, number of path, and pattern on surface integrity characteristics such as surface topography, roughness, microhardness, and microstructure are investigated.

  8. Corrosion and wear protective composition modulated alloy coatings based on ternary Ni-P-X alloys

    DEFF Research Database (Denmark)

    Leisner, P.; Benzon, M. E.; Christoffersen, Lasse

    1996-01-01

    Scattered reporting in the litterature describes a number of ternary Ni-P-X alloyes (where X can be Co, Cr, Cu, Mo, Pd, Re or W) with promising corrosin and wear protective performance. Based on a systematic study of Ni-P-X alloys it is the intention to produce coatings with improved corrosion...

  9. 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.

  10. Green superlubricity of Nitinol 60 alloy against steel in presence of castor oil

    Science.gov (United States)

    Zeng, Qunfeng; Dong, Guangneng; Martin, Jean Michel

    2016-07-01

    In the present work, first, we show that sliding Nitinol 60 alloy against steel under castor oil lubrication exhibits a new case of superlubricity (coefficient of friction CoF ≪ 0.01). So far, CoF below 0.01 have never been achieved under boundary lubrication at high contact pressure and in presence of vegetable oil as a green lubricant. Next, it is demonstrated that superlubricity is controlled by tribochemical reactions, involving chemical degradation of castor oil and the formation of metal oxy-hydroxides. Finally, to explain these findings, we propose a novel superlubricity mechanism consisting of hexanoic acid molecules intercalated between nickel and iron oxy-hydroxide lamellar layers, a structure very similar to the one found in Fe-Ni batteries. We propose that superlubricity is achieved due to repulsive electrostatic forces acting between the intercalated metal oxy-hydroxide lamellar compounds. This system would be suitable for practical engineering applications in many fields including biotechnologies.

  11. Determining Micromechanical Strain in Nitinol

    Energy Technology Data Exchange (ETDEWEB)

    Strasberg, Matthew; /SLAC

    2006-09-27

    Nitinol is a superelastic alloy made of equal parts nickel and titanium. Due to its unique shape memory properties, nitinol is used to make medical stents, lifesaving devices used to allow blood flow in occluded arteries. Micromechanical models and even nitinol-specific finite element analysis (FEA) software are insufficient for unerringly predicting fatigue and resultant failure. Due to the sensitive nature of its application, a better understanding of nitinol on a granular scale is being pursued through X-ray diffraction techniques at the Stanford Synchrotron Radiation Laboratory (SSRL) at the Stanford Linear Accelerator Center (SLAC). Through analysis of powder diffraction patterns of nitinol under increasing tensile loads, localized strain can be calculated. We compare these results with micromechanical predictions in order to advance nitinol-relevant FEA tools. From this we hope to gain a greater understanding of how nitinol fatigues under multi-axial loads.

  12. Model for the Prediction of the Hydriding Thermodynamics of Pd-Rh-Co Ternary Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Teter, D.F.; Thoma, D.J.

    1999-03-01

    A dilute solution model (with respect to the substitutional alloying elements) has been developed, which accurately predicts the hydride formation and decomposition thermodynamics and the storage capacities of dilute ternary Pd-Rh-Co alloys. The effect of varying the rhodium and cobalt compositions on the thermodynamics of hydride formation and decomposition and hydrogen capacity of several palladium-rhodium-cobalt ternary alloys has been investigated using pressure-composition (PC) isotherms. Alloying in the dilute regime (<10 at.%) causes the enthalpy for hydride formation to linearly decrease with increasing alloying content. Cobalt has a stronger effect on the reduction in enthalpy than rhodium for equivalent alloying amounts. Also, cobalt reduces the hydrogen storage capacity with increasing alloying content. The plateau thermodynamics are strongly linked to the lattice parameters of the alloys. A near-linear dependence of the enthalpy of hydride formation on the lattice parameter was observed for both the binary Pd-Rh and Pd-Co alloys, as well as for the ternary Pd-Rh-Co alloys. The Pd-5Rh-3Co (at. %) alloy was found to have similar plateau thermodynamics as a Pd-10Rh alloy, however, this ternary alloy had a diminished hydrogen storage capacity relative to Pd-10Rh.

  13. Dynamical simulation of sputtering and reflection from a ternary alloy

    Science.gov (United States)

    Ishida, M.; Yamaguchi, Y.; Yoshinaga, H.; Yamamura, Y.

    The sputtering and the reflection from a Tb0.2Fe0.7Co0.1 alloy due to Ar+ ion bombardment have been investigated by the Monte Carlo simulation code ACAT-DIFFUSE which include the compositional change induced by ion influence. In the Tb-Fe-Co system, Fe atoms are preferentially sputtered. The atomic size of a Tb atom is the largest of these three atoms, and so Tb atoms trap preferentially in vacancies. The steady-state concentration of Tb atoms at the topmost layer is larger than the bulk concentration for the low energy ions due to radiation-induced segregation and preferential sputtering of Fe atoms. As the ion fluence increases, the atomic fractions of sputtered atoms calculated by the ACAT-DIFFUSE code become those of the bulk concentration. The depth profiles of each element at the steady state depend on the incident energy. The total sputtering yield and the reflection coefficient from a Tb-Fe-Co alloy calculated by the ACAT-DIFFUSE code are larger than those by the ACAT code at near-threshold energies, where the ACAT code does not include the ion-influence effect. The energy spectra of back-scattered Ar atoms from the present ternary alloy have very similar profiles to those from a monoatomic Tb target, especially for low-energy Ar+ ions.

  14. Impact toughness of ternary Al–Zn–Mg alloys in as cast and ...

    Indian Academy of Sciences (India)

    Unknown

    present work. The alloys were used in as cast and homogenized condition purely on the basis of theoretical and academic interest. 2. Experimental. Al–Zn–Mg alloys were obtained by melt casting and air ... six ternary alloys of different compositions were obtained. ... the ratio of shear stress to normal stress (it is equal to 1.

  15. Review of Reactivity Experiments for Lithium Ternary Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Jolodosky, A. [Univ. of California, Berkeley, CA (United States); Bolind, A. [Univ. of California, Berkeley, CA (United States); Fratoni, M. [Univ. of California, Berkeley, CA (United States)

    2015-09-28

    Lithium is often the preferred choice as breeder and coolant in fusion blankets as it offers high tritium breeding, excellent heat transfer and corrosion properties, and most importantly, it has very high tritium solubility and results in very low levels of tritium permeation throughout the facility infrastructure. However, lithium metal vigorously reacts with air and water and exacerbates plant safety concerns. Consequently, Lawrence Livermore National Laboratory (LLNL) is attempting to develop a lithium-based alloy—most likely a ternary alloy—which maintains the beneficial properties of lithium (e.g. high tritium breeding and solubility) while reducing overall flammability concerns for use in the blanket of an inertial fusion energy (IFE) power plant. The LLNL concept employs inertial confinement fusion (ICF) through the use of lasers aimed at an indirect-driven target composed of deuterium-tritium fuel. The fusion driver/target design implements the same physics currently experimented at the National Ignition Facility (NIF). The plant uses lithium in both the primary coolant and blanket; therefore, lithium related hazards are of primary concern. Reducing chemical reactivity is the primary motivation for the development of new lithium alloys, and it is therefore important to come up with proper ways to conduct experiments that can physically study this phenomenon. This paper will start to explore this area by outlining relevant past experiments conducted with lithium/air reactions and lithium/water reactions. Looking at what was done in the past will then give us a general idea of how we can setup our own experiments to test a variety of lithium alloys.

  16. Biocompatibility and strength properties of nitinol shape memory alloy suture in rabbit tendon.

    Science.gov (United States)

    Kujala, Sauli; Pajala, Ari; Kallioinen, Matti; Pramila, Antti; Tuukkanen, Juha; Ryhänen, Jorma

    2004-01-01

    Nitinol (NiTi) is a promising new tendon suture material with good strength, easy handling and good super-elastic properties. NiTi sutures were implanted for biocompatibility testing into the right medial gastrocnemius tendon in 15 rabbits for 2, 6 and 12 weeks. Additional sutures were implanted in subcutaneous tissue for strength measurements in order to determine the effect of implantation on strength properties of NiTi suture material. Braided polyester sutures (Ethibond) of approximately the same diameter were used as control. Encapsulating membrane formation around the sutures was minimal in the case of both materials. The breaking load of NiTi was significantly greater compared to braided polyester. Implantation did not affect the strength properties of either material.

  17. Silver deposition on polypyrrole films electrosynthesised onto Nitinol alloy. Corrosion protection and antibacterial activity.

    Science.gov (United States)

    Saugo, M; Flamini, D O; Brugnoni, L I; Saidman, S B

    2015-11-01

    The electrosynthesis of polypyrrole films onto Nitinol from sodium salicylate solutions of different concentrations is reported. The morphology and corrosion protection properties of the resulting coatings were examined and they both depend on the sodium salicylate concentration. The immobilisation of silver species in PPy films constituted by hollow rectangular microtubes was studied as a function of the polymer oxidation degree. The highest amount of silver was deposited when the coated electrode was prepolarised at -1.00V (SCE) before silver deposition, suggesting an increase in the amount of non-oxidised segments in the polymer. Finally, the antibacterial activity of the coating against the Gram positive Staphylococcus aureus and Staphylococcus epidermidis bacteria was evaluated. Both strains resulted sensitive to the modified coatings, obtaining a slightly better result against S. aureus. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. FUNCTIONAL COATINGS BY TERNARY COBALT BASED ALLOYS FOR THE AUTUMOBILE INDUSTRY

    Directory of Open Access Journals (Sweden)

    T. Nenastіna

    2015-07-01

    Full Text Available The environmentally friendly and resource-saving technologies for producing multifunctional coatings based on cobalt and silver alloys with refractory metals are proposed. The catalytic activity testing results of binary and ternary alloys based on cobalt in the carbon monoxide oxidation reaction in carbon dioxide were analyzed. It was revealed that there is on improvement of functional properties of galvanic alloys when the content of tungsten and molybdenum is within the range of 10–30 wt. %.

  19. Deviations from Vegard’s law in ternary III-V alloys

    KAUST Repository

    Murphy, S. T.

    2010-08-03

    Vegard’s law states that, at a constant temperature, the volume of an alloy can be determined from a linear interpolation of its constituent’s volumes. Deviations from this description occur such that volumes are both greater and smaller than the linear relationship would predict. Here we use special quasirandom structures and density functional theory to investigate such deviations for MxN1−xAs ternary alloys, where M and N are group III species (B, Al, Ga, and In). Our simulations predict a tendency, with the exception of AlxGa1−xAs, for the volume of the ternary alloys to be smaller than that determined from the linear interpolation of the volumes of the MAs and BAs binary alloys. Importantly, we establish a simple relationship linking the relative size of the group III atoms in the alloy and the predicted magnitude of the deviation from Vegard’s law.

  20. Thermodynamics of Ga ternary alloys with Na and In, Sn or Zn

    Energy Technology Data Exchange (ETDEWEB)

    Dergacheva, M.B. [Institute of Org. Catalysis and Electrochem. NAN RK, Almaty (Kazakhstan); Shatrova, E.G. [Institute of Org. Catalysis and Electrochem. NAN RK, Almaty (Kazakhstan); Harina, O.V. [Institute of Org. Catalysis and Electrochem. NAN RK, Almaty (Kazakhstan)

    1996-12-01

    Thermodynamic properties of ternary liquid Ga alloys, containing Na (X{sub Na} = 0.025 to 0.045) and In, Sn or Zn have been determined by e.m.f. measurements. The partial thermodynamic properties of Na ({alpha}{sub Na}, {gamma}{sub Na}, {Delta} anti G{sub Na}, {Delta} anti S{sub Na}) have been calculated. The interaction of Na with the other components decreases in the following sequence: In => Sn => Zn. The liquidus temperatures of the investigated ternary alloys have been also determined. (orig.)

  1. Dynamic solidification mechanism of ternary Ag-Cu-Ge eutectic alloy under ultrasonic condition

    Science.gov (United States)

    Zhai, Wei; Hong, ZhenYu; Mei, CeXiang; Wang, WeiLi; Wei, BingBo

    2013-02-01

    The dynamic solidification of ternary Ag38.5Cu33.4Ge28.1 eutectic alloy within a 35 kHz ultrasonic field is investigated and compared with both its equilibrium solidification by DSC method and its rapid solidification in drop tube. The volume fractions of the primary (Ge) phase and pseudobinary (Ag+ ɛ 2) eutectic solidified within ultrasonic field are larger than those formed under equilibrium state, whereas that of ternary (Ag+ ɛ 2+Ge) eutectic exhibits the reverse trend. During rapid solidification, the liquid alloy droplet directly solidifies into ternary (Ag+ ɛ 2+Ge) eutectic if its diameter is smaller than 350 μm. The ultrasound stimulates the nucleation of alloy melt and prevents the bulk undercooling. With the increase of sound intensity, the primary (Ge) phase transfers from faceted dendrites to nonfaceted blocks with blunt edges, and its grain size is remarkably reduced. Both pseudobinary (Ag+ ɛ 2) and ternary (Ag+ ɛ 2+Ge) eutectics experience a morphological transition from regular to anomalous structures. This indicates that their cooperative growth mode is replaced by independent growth of eutectic phases under the combined effects of cavitation and acoustic streaming. The ultrasound also shows a prominent coarsening effect to the pseudobinary (Ag+ ɛ 2) and ternary (Ag+ ɛ 2 +Ge) eutectics.

  2. Corrosion Characteristics of Ti-29Nb-xHf Ternary Alloy for Biomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Pak, Sun Young; Choi, Han Chul [Chosun Univ., Kwangju (Korea, Republic of)

    2015-12-15

    The Cp-Ti and Ti-6Al-4V alloys were widely used for dental materials due to their mechanical properties and good corrosion resistance. However, Cp-Ti was known as bio-inert materials, Ti-6Al-4V alloy has a problem such as high Young modulus, potential loss of the surrounding bone, and to the release of potentially toxic ions from the alloy. To overcome this problem, Ti alloys containing Nb and Hf elements have been used for biomaterials due to low toxicity and high corrosion resistance. Especially, alloying element of Nb was known as β phase stabilizer. The β phase alloy was widely used to replace currently used implant materials. The corrosion resistances of Ti-29Nb-xHf ternary alloys were dependent on Hf content in oral environment solution.

  3. Properties of ternary NiFeW alloy coating by jet electrodeposition

    Indian Academy of Sciences (India)

    17

    Abstract. In this paper, ternary NiFeW alloy coatings were prepared by jet electrodeposition, and the effects of lord salt concentration, jet speed, current density, and temperature on the properties of the coatings, including the composition, microhardness, surface morphology, structure, and corrosion resistance, were ...

  4. Organic alloy systems suitable for the investigation of regular binary and ternary eutectic growth

    Science.gov (United States)

    Sturz, L.; Witusiewicz, V. T.; Hecht, U.; Rex, S.

    2004-09-01

    Transparent organic alloys showing a plastic crystal phase were investigated experimentally using differential scanning calorimetry and directional solidification with respect to find a suitable model system for regular ternary eutectic growth. The temperature, enthalpy and entropy of phase transitions have been determined for a number of pure substances. A distinction of substances with and without plastic crystal phases was made from their entropy of melting. Binary phase diagrams were determined for selected plastic crystal alloys with the aim to identify eutectic reactions. Examples for lamellar and rod-like eutectic solidification microstructures in binary systems are given. The system (D)Camphor-Neopentylglycol-Succinonitrile is identified as a system that exhibits, among others, univariant and a nonvariant eutectic reaction. The ternary eutectic alloy close to the nonvariant eutectic composition solidifies with a partially faceted solid-liquid interface. However, by adding a small amount of Amino-Methyl-Propanediol (AMPD), the temperature of the nonvariant eutectic reaction and of the solid state transformation from plastic to crystalline state are shifted such, that regular eutectic growth with three distinct nonfaceted phases is observed in univariant eutectic reaction for the first time. The ternary phase diagram and examples for eutectic microstructures in the ternary and the quaternary eutectic alloy are given.

  5. The structure and physical properties of the ternary CuZnPt{sub 6} alloy

    Energy Technology Data Exchange (ETDEWEB)

    Ziya, A.B. [Department of Physics, Bahauddin Zakariya University, Multan-60800 (Pakistan); Institute of Materials Science, University of Tsukuba, Tsukuba 305-8573 (Japan)], E-mail: amer_ziya@yahoo.com; Takahashi, M.; Ohshima, K. [Institute of Materials Science, University of Tsukuba, Tsukuba 305-8573 (Japan)

    2008-07-01

    The ternary addition of Zn to the binary Cu-Pt system was found to result in a complete miscibility at a stoichiometric composition of CuZnPt{sub 6}. The equilibrium ground state structure is face-centered cubic (fcc) (A{sub 1}-type). The results are associated with the alloying behavior in the ternary CuMPt{sub 6} (M=3d metals) system reported previously. They verify the fact that the Pt-based primary solid solution found in binary MPt{sub 3} alloys extends its region in the phase diagram to the composition of Cu:M:Pt=1:1:6. The Debye temperature ({theta}{sub D}) obtained is smaller than that of pure Pt, whereas no significant effect is observed on the linear thermal expansion and magnetic property of the alloy.

  6. Ternary diffusion in Cu-rich fcc Cu–Al–Si alloys at 1073 K

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Dandan [School of Materials Science and Engineering, Central South University, Changsha, Hunan 410083 (China); State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Zhang, Lijun [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Du, Yong, E-mail: yongducalphad@gmail.com [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Xu, Honghui [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Jin, Zhanpeng [School of Materials Science and Engineering, Central South University, Changsha, Hunan 410083 (China)

    2013-07-25

    Highlights: •Interdiffusivities in Cu-rich fcc Cu–Al–Si alloys at 1073 K were determined. •The present results were compared with experimental data in boundary binary systems. •The present results were validated by thermodynamic constraints and Fick’s law. •The sign of ternary cross diffusivities was predicted in terms of thermodynamics. -- Abstract: Utilizing six groups of bulk diffusion couples and with electron probe microanalysis technique, the composition dependence of ternary interdiffusion coefficients in Cu-rich fcc Cu–Al–Si alloys at 1073 K were determined by the Matano-Kirkaldy method. Using a three-dimensional representation, the obtained main ternary diffusion coefficients were found to be consistent with the experimental data in boundary binaries available in the literature. The reliability of the obtained interdiffusivities was further validated by thermodynamic constraints as well as by Fick’s second law applied to numerical simulation. The sign of the ternary cross diffusivities in fcc Cu–Al–Si alloys, which shows a noticeable effect on microstructure, was also successfully predicted in terms of thermodynamics.

  7. Molecular dynamics investigation of the thermal conductivity of ternary silicon–germanium–tin alloys

    Science.gov (United States)

    Lee, Yongjin; Hwang, Gyeong S.

    2017-12-01

    A further reduction of the thermal conductivity (κ) of silicon-germanium (SiGe) alloys is indispensable for their use as thermoelectric materials. Thus far, heteroatom-doped and nanostructured SiGe systems have been mainly synthesized and tested. This work presents a possibility of reducing the κ of SiGe by alloying with tin (Sn). Our molecular dynamics simulations predict that the κ of ternary SiGeSn alloys can be 40% lower than those of binary SiGe and GeSn alloys due mainly to increased mass disorder scattering of phonons. Our findings provide insight into the mechanism of κ suppression in multielement alloys and guidance on how to design them for thermoelectric applications.

  8. Mechanical properties identification and design optimization of nitinol shape memory alloy microactuators

    Science.gov (United States)

    Salehi, M.; Hamedi, M.; Salmani Nohouji, H.; Arghavani, J.

    2014-02-01

    Microactuators are essential elements of MEMS and are widely used in these devices. Microgrippers, micropositioners, microfixtures, micropumps and microvalves are well-known applications of microstructures. In this paper, the design optimization of shape memory alloy microactuators is discussed. Four different configurations of microactuator with variable geometrical parameters, generating different levels of displacement and force, are designed and analysed. In order to determine the optimum values of parameters for each microactuator, statistical design of experiments (DOE) is used. For this purpose, the Souza et al constitutive model (1988 Eur. J. Mech. A 17 789-806) is adapted for use in finite element analysis software. Mechanical properties of the SMA are identified by performing experimental tests on Ti-49.8%Ni. Finally, the specific energy of each microactuator is determined using the calibrated model and regression analysis. Moreover, the characteristic curve of each microactuator is obtained and with this virtual tool one can choose a microactuator with the desired force and displacement. The methodology discussed in this paper can be used as a reference to design appropriate microactuators for different MEMS applications producing various ranges of displacement and force.

  9. Phenomena of nanotube nucleation and growth on new ternary titanium alloys.

    Science.gov (United States)

    Choe, Han-Cheol; Jeong, Yong-Hoon; Brantley, William A

    2010-07-01

    Ti-30Nb-xZr and Ti-30Ta-xNb alloys have been investigated using various methods of surface nanotube formation. Ternary Ti-30Nb-xZr (x = 3 and 15 wt%) and Ti-30Ta-xNb (x = 3 and 15 wt%) alloys were prepared by using high-purity sponge Ti (Grade 4, G&S Titanium, USA), Ta, Zr and Nb spheres. The two groups of ternary Ti alloys were prepared using a vacuum arc melting furnace. Nanotube formation was carried out with a conventional three-electrode configuration with the Ti alloy specimen, a platinum counterelectrode, and a saturated calomel (SCE) reference electrode. Experiments were performed in 1 M H3PO4 with small additions of NaF (0.1-0.8 wt%), using a potentiostat. Nanotubes formed on the surfaces of the two ternary Ti alloys were examined by field emission scanning electron microscopy, EDS and XRD. The Ti-30Ta-xZr alloys had microstructure with entirely needle-like constituents; the thickness of the needle-like alpha-phase increased as the Zr content increased. The Ti-30Nb-xZr alloys had equiaxed microstructures of the beta-phase, and increasing amounts of the needle-like alpha phase appeared at the grain boundaries of the beta-phase as the Zr content increased. The nanotubes were nucleated and grew mainly on the beta phase for the Ti-30Ta-3Zr and Ti-30Nb-3Zr alloys, which had nanotubes with uniform shape, but the nanotubes were nucleated at the alpha phase for the Ti-30Ta-15Zr and Ti-30Nb-15Zr alloys, which had nanotubes with irregular shape and diameters of two sizes. The diameter and depth of the nanotubes could be controlled, depending upon the alloy composition and composition of the surface oxide films (TiO2, Nb2O5, Ta2O5, and ZrO2). It is concluded that this research that selection of the appropriate alloying element can allow significant control of the nanotopography of these Ti alloy surfaces and that it is possible to control the surface nanotube size to promote long-term osseointegration for clinical dental or orthopedic use.

  10. Magnetic features of a mixed ferro-ferrimagnetic ternary alloy cylindrical nanowire

    Science.gov (United States)

    Vatansever, Z. D.

    2017-10-01

    In the present study, we have investigated the finite temperature magnetic phase transition properties of a mixed ferro-ferrimagnetic ternary alloy cylindrical nanowire of the type ABpC1-p by Monte Carlo simulation technique. The nanowire system consists of two interpenetrating sublattices, one of which contains type-A magnetic components with spin-3/2 and the other one is randomly occupied type-B and type-C magnetic components with spin-1 and spin-5/2, respectively. We have examined the effect of exchange interaction ratio, R, and the concentration value of type-B magnetic ions, p, on the transition temperature of the system. It has been found that one can modify the transition temperature and saturation magnetization of the system by varying concentration value and interaction ratio. Moreover, our numerical results show that the ternary alloy nanowire system exhibits compensation behavior for particular values of the system parameters.

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

    KAUST Repository

    Chroneos, Alexander I.

    2010-06-01

    Simulation of defect interactions in binary/ternary group IV semiconductor alloys at the density functional theory level is difficult due to the random distribution of the constituent atoms. The special quasirandom structures approach is a computationally efficient way to describe the random nature. We systematically study the efficacy of the methodology and generate a number of special quasirandom cells for future use. In order to demonstrate the applicability of the technique, the electronic structures of E centers in Si1-xGex and Si1-x -yGexSny alloys are discussed for a range of nearest neighbor environments. © 2010 Elsevier B.V. All rights reserved.

  12. E centers in ternary Si1−x−yGexSny random alloys

    KAUST Repository

    Chroneos, Alexander

    2009-09-14

    Density functional theory calculations are used to study the association of arsenic (As) atoms to lattice vacancies and the formation of As-vacancy pairs, known as E centers, in the random Si0.375Ge0.5Sn0.125 alloy. The local environments are described by 32-atom special quasirandom structures that represent random Si1−x−yGexSny alloys. It is predicted that the nearest-neighbor environment will exert a strong influence on the stability of E centers in ternary Si0.375Ge0.5Sn0.125.

  13. High Permeability Ternary Palladium Alloy Membranes with Improved Sulfur and Halide Tolerances

    Energy Technology Data Exchange (ETDEWEB)

    K. Coulter

    2010-12-31

    The project team consisting of Southwest Research Institute{reg_sign} (SwRI{reg_sign}), Georgia Institute of Technology (GT), the Colorado School of Mines (CSM), TDA Research, and IdaTech LLC was focused on developing a robust, poison-tolerant, hydrogen selective free standing membrane to produce clean hydrogen. The project completed on schedule and on budget with SwRI, GT, CSM, TDA and IdaTech all operating independently and concurrently. GT has developed a robust platform for performing extensive DFT calculations for H in bulk palladium (Pd), binary alloys, and ternary alloys of Pd. Binary alloys investigated included Pd96M4 where M = Li, Na, Mg, Al, Si, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Y, Zr, Nb, Mo, Tc, Ru, Rh, Ag, Cd, In, Sn, Sb, Te, Hf, Ta, W, Re, Os, Ir, Pt, Au, Tl, Pb, Bi, Ce, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu. They have also performed a series of calculations on Pd{sub 70}Cu{sub 26}Ag{sub 4}, Pd{sub 70}Cu{sub 26}Au{sub 4}, Pd{sub 70}Cu{sub 26}Ni{sub 4}, Pd{sub 70}Cu{sub 26}Pt{sub 4}, and Pd{sub 70}Cu{sub 26}Y{sub 4}. SwRI deposited and released over 160 foils of binary and ternary Pd alloys. There was considerable work on characterizing and improving the durability of the deposited foils using new alloy compositions, post annealing and ion bombardment. The 10 and 25 {micro}m thick films were sent to CSM, TDA and IdaTech for characterization and permeation testing. CSM conducted over 60 pure gas permeation tests with SwRI binary and ternary alloy membranes. To date the PdAu and PdAuPt membranes have exhibited the best performance at temperatures in the range of 423-773 C and their performance correlates well with the predictions from GT. TDA completed testing under the Department of Energy (DOE) WGS conditions on over 16 membranes. Of particular interest are the PdAuPt alloys that exhibited only a 20% drop in flux when sulfur was added to the gas mixture and the flux was completely recovered when the sulfur flow was stopped. IdaTech tested binary

  14. Novel PdAgCu ternary alloy: Hydrogen permeation and surface properties

    Energy Technology Data Exchange (ETDEWEB)

    Tarditi, Ana M.; Braun, Fernando [Instituto de Investigaciones en Catalisis y Petroquimica (FIQ, UNL-CONICET), Santiago del Estero 2829, 3000 Santa Fe (Argentina); Cornaglia, Laura M., E-mail: lmcornag@fiq.unl.edu.ar [Instituto de Investigaciones en Catalisis y Petroquimica (FIQ, UNL-CONICET), Santiago del Estero 2829, 3000 Santa Fe (Argentina)

    2011-05-15

    Dense PdAgCu ternary alloy composite membranes were synthesized by the sequential electroless plating of Pd, Ag and Cu on top of both disk and tubular porous stainless steel substrates. X-ray diffraction and scanning electron microscopy were employed to study the structure and morphology of the tested samples. The hydrogen permeation performance of these membranes was investigated over a 350-450 deg. C temperature range and a trans-membrane pressure up to 100 kPa. After annealing at 500 deg. C in hydrogen stream followed by permeation experiments, the alloy layer presented a FCC crystalline phase with a bulk concentration of 68% Pd, 7% Ag and 25% Cu as revealed by EDS. The PdAgCu tubular membrane was found to be stable during more than 300 h on hydrogen stream. The permeabilities of the PdAgCu ternary alloy samples were higher than the permeabilities of the PdCu alloy membranes with a FCC phase. The co-segregation of silver and copper to the membrane surface was observed after hydrogen permeation experiments at high temperature as determined by XPS.

  15. Alloy multilayers and ternary nanostructures by direct-write approach

    Science.gov (United States)

    Porrati, F.; Sachser, R.; Gazzadi, G. C.; Frabboni, S.; Terfort, A.; Huth, M.

    2017-10-01

    The fabrication of nanopatterned multilayers, as used in optical and magnetic applications, is usually achieved by two independent steps, which consist in the preparation of multilayer films and in the successive patterning by means of lithography and etching processes. Here we show that multilayer nanostructures can be fabricated by using focused electron beam induced deposition (FEBID), which allows the direct writing of nanostructures of any desired shape with nanoscale resolution. In particular, {[{{{Co}}}2{{Fe}}/{{Si}}]}n multilayers are prepared by the alternating deposition from the metal carbonyl precursors, {{{HFeCo}}}3{({{CO}})}12 and {{Fe}}{({{CO}})}5, and neopentasilane, {{{Si}}}5{{{H}}}12. The ability to fabricate nanopatterned multilayers by FEBID is of interest for the realization of hyperbolic metamaterials and related nanodevices. In a second experiment, we treated the multilayers by low-energy electron irradiation in order to induce atomic species intermixing with the purpose to obtain ternary nanostructured compounds. Transmission electron microscopy and electrical transport measurements indicate that in thick multilayers, (n = 12), the intermixing is only partial, taking place mainly in the upper part of the structures. However, for thin multilayers, (n = 2), the intermixing is such that a transformation into the L21 phase of the Co2FeSi Heusler compound takes place over the whole sample volume.

  16. Correlated process of phase separation and microstructure evolution of ternary Co-Cu-Pb alloy

    Science.gov (United States)

    Yan, N.; Wang, W. L.; Luo, S. B.; Hu, L.; Wei, B.

    2013-11-01

    The phase separation and rapid solidification of liquid ternary Co45Cu42Pb13 immiscible alloy have been investigated under both bulk undercooling and containerless processing conditions. The undercooled bulk alloy is solidified as a vertical two-layer structure, whereas the containerlessly solidified alloy droplet is characterized by core-shell structures. The dendritic growth velocity of primary α(Co) phase shows a power-law relation to undercooling and achieves a maximum of 1.52 m/s at the undercooling of 112 K. The Pb content is always enriched in Cu-rich zone and depleted in Co-rich zone. Numerical analyses indicate that the Stokes motion, solutal Marangoni convection, thermal Marangoni convection, and interfacial energy play the main roles in the correlated process of macrosegregation evolution and microstructure formation.

  17. Surface modification of Ni–Ti alloys for stent application after magnetoelectropolishing

    Energy Technology Data Exchange (ETDEWEB)

    Gill, Puneet; Musaramthota, Vishal; Munroe, Norman [Department of Mechanical and Materials Engineering, Florida International University, Miami, FL 33174 (United States); Datye, Amit [Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37916 (United States); Dua, Rupak [Department of Biomedical Engineering, Florida International University, Miami, FL 33174 (United States); Haider, Waseem [Mechanical Engineering, University of Texas-Pan American, TX (United States); McGoron, Anthony [Department of Biomedical Engineering, Florida International University, Miami, FL 33174 (United States); Rokicki, Ryszard [Electrobright, Macungie, PA 18062 (United States)

    2015-05-01

    The constant demand for new implant materials and the multidisciplinary design approaches for stent applications have expanded vastly over the past decade. The biocompatibility of these implant materials is a function of their surface characteristics such as morphology, surface chemistry, roughness, surface charge and wettability. These surface characteristics can directly influence the material's corrosion resistance and biological processes such as endothelialization. Surface morphology affects the thermodynamic stability of passivating oxides, which renders corrosion resistance to passivating alloys. Magnetoelectropolishing (MEP) is known to alter the morphology and composition of surface films, which assist in improving corrosion resistance of Nitinol alloys. This work aims at analyzing the surface characteristics of MEP Nitinol alloys by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The wettability of the alloys was determined by contact angle measurements and the mechanical properties were assessed by Nanoindentation. Improved mechanical properties were observed with the addition of alloying elements. Cyclic potentiodynamic polarization tests were performed to determine the corrosion susceptibility. Further, the alloys were tested for their cytotoxicity and cellular growth with endothelial cells. Improved corrosion resistance and cellular viability were observed with MEP surface treated alloys. - Highlights: • Magnetoelectropolishing (MEP) reduces the surface asperities of Nitinol alloys and formed stable oxides on the surface. • Improved corrosion resistance and reduced Nickel ion leaching were observed for MEP surfaces. • Ni–Ti alloyed with Cr showed improved mechanical properties. • Enhanced endothelial cell proliferation on ternary Nitinol alloys.

  18. Educational Pathways through Nanoscience: Nitinol as a Paradigmatic Smart Material

    Science.gov (United States)

    Lisotti, Annamaria; De Renzi, Valentina; Rozzi, Carlo Andrea; Villa, Elena; Albertini, Franca; Goldoni, Guido

    2013-01-01

    We developed an educational path based on nitinol, a shape memory alloy which conveniently exemplifies the smart material concept, i.e., a material that performs a predetermined, reversible action in response to a change in the environment. Nitinol recovers a given shape, changes its resistivity drastically and modifies its elastic properties if…

  19. A first-principles model for anomalous segregation in dilute ternary tungsten-rhenium-vacancy alloys

    Science.gov (United States)

    Wróbel, J. S.; Nguyen-Manh, D.; Kurzydłowski, K. J.; Dudarev, S. L.

    2017-04-01

    The occurrence of segregation in dilute alloys under irradiation is a highly unusual phenomenon that has recently attracted attention, stimulated by the interest in the fundamental properties of alloys as well as by their applications. The fact that solute atoms segregate in alloys that, according to equilibrium thermodynamics, should exhibit full solubility, has significant practical implications, as the formation of precipitates strongly affects physical and mechanical properties of alloys. A lattice Hamiltonian, generalizing the so-called ‘ABV’ Ising model and including collective many-body inter-atomic interactions, has been developed to treat rhenium solute atoms and vacancies in tungsten as components of a ternary alloy. The phase stability of W-Re-vacancy alloys is assessed using a combination of density functional theory (DFT) calculations and cluster expansion (CE) simulations. The accuracy of CE parametrization is evaluated against the DFT data, and the cross-validation error is found to be less than 4.2 meV/atom. The free energy of W-Re-vacancy ternary alloys is computed as a function of temperature using quasi-canonical Monte Carlo simulations, using effective two, three and four-body interactions. In the low rhenium concentration range (<5 at. % Re), solute segregation is found to occur in the form of voids decorated by Re atoms. These vacancy-rhenium clusters remain stable over a broad temperature range from 800 K to 1600 K. At lower temperatures, simulations predict the formation of Re-rich rhenium-vacancy clusters taking the form of sponge-like configurations that contain from 30 to 50 at. % Re. The anomalous vacancy-mediated segregation of Re atoms in W can be rationalized by analyzing binding energy dependence as a function of Re to vacancy ratio as well as chemical Re-W and Re-vacancy interactions and short-range order parameters. DFT calculations show that rhenium-vacancy binding energies can be as high as 1.5 eV if the rhenium

  20. Mapping of Diffusion and Nanohardness Properties of Fcc Co-Al-V Alloys Using Ternary Diffusion Couples

    Science.gov (United States)

    Wang, Chuanyun; Xu, Guanglong; Cui, Yuwen

    2017-09-01

    Ternary diffusion behavior in Co-Al-V ternary alloys was investigated at 1373 K and 1473 K (1100 °C and 1200 °C) by the solid-state diffusion-couple technique. The extraction and interpolation of diffusion data allows the diffusion properties of Fcc Co-Al-V alloys to be mapped in the composition arrays of Al and V. A full picture of the diffusion properties was then constructed by interpolating all accessible interdiffusivities and impurity diffusivities of Co-Al binary and Co-Al-V ternary with a Redlich-Kister polynomial, in a graphic manner depicting a rapid increase of Al diffusion with increasing Al and a weak decrease with the V addition alone. Further incorporation of a nanoindentation technique enables the nanohardness property of the Co-Al-V fcc alloys to be screened in the Al and V arrays. The hardenability in the Co-Al-V alloy system has been evidenced; specifically, the alloy arrays containing higher contents of V, being solution-and-quenching processed, exhibit more effective strengthening than those with the addition of Al. The discovery of Co-Al-V alloys with comparable nanohardness but differing alloy compositions could facilitate the strengthening design of next generation Co-based alloys.

  1. Robust tribo-mechanical and hot corrosion resistance of ultra-refractory Ta-Hf-C ternary alloy films.

    Science.gov (United States)

    Yate, Luis; Coy, L Emerson; Aperador, Willian

    2017-06-08

    In this work we report the hot corrosion properties of binary and ternary films of the Ta-Hf-C system in V 2 O 5 -Na 2 SO 4 (50%wt.-50%wt.) molten salts at 700 °C deposited on AISI D3 steel substrates. Additionally, the mechanical and nanowear properties of the films were studied. The results show that the ternary alloys consist of solid solutions of the TaC and HfC binary carbides. The ternary alloy films have higher hardness and elastic recoveries, reaching 26.2 GPa and 87%, respectively, and lower nanowear when compared to the binary films. The corrosion rates of the ternary alloys have a superior behavior compared to the binary films, with corrosion rates as low as 0.058 μm/year. The combination and tunability of high hardness, elastic recovery, low nanowear and an excellent resistance to high temperature corrosion demonstrates the potential of the ternary Ta-Hf-C alloy films for applications in extreme conditions.

  2. Stability of a density-change flow in the solidification of a ternary alloy

    Science.gov (United States)

    Guba, Peter; Anderson, Daniel

    2017-11-01

    We consider phase-change driven flow and solidification of a ternary (three-component) alloy. The ternary system is characterized by the formation of two distinct mushy layers (primary and secondary), distinguished by the number of components present in their solid phases. A primary layer has the solid phase composed of a single component and, beneath the primary layer, a secondary layer has the solid phase composed of two components. Generally, the densities of the liquid, primary solid and secondary solid phases during solidification are different, and these differences give rise to a flow of the interstitial liquid. We identify four different flow regimes dependent upon whether the two solid phases shrink or expand upon solidification. The stability of this density-change flow in the absence of buoyancy is studied numerically applying a spectral method. A simple power law is employed to describe the permeability of the ternary mushy layers, with a sensitivity of permeability to changes in porosity used as the control parameter. An instability is found to occur not only in the case of expansion but also contraction, an option that is apparently unavailable for the binary case. A reduced model is derived which contains the bare essentials required to capture this instability.

  3. Morphological study of ternary Ni Cu P alloys by atomic force microscopy

    Science.gov (United States)

    Balaraju, J. N.; Anandan, C.; Rajam, K. S.

    2005-08-01

    Ternary electroless Ni-Cu-P alloy films were deposited by using nickel sulphate (B1)- and nickel chloride (B2)-based alkaline baths. Alloy films were characterized for their structure, morphology, chemical composition and microhardness. A single broad peak was obtained in XRD for both B1 and B2 films and the calculated grain sizes are 1.6 and 1.9 nm, respectively. Optical microscopic examination of the deposited coatings revealed a less nodular structure for B2-based coatings. SEM micrographs showed that films were smooth and nodular. Compositional analysis made on these deposits using EDX and the chemical state identification by XPS showed that the coatings are almost identical. AFM studies showed that the deposits from B2 bath are comparatively smoother with less nodular structure. Microhardness measurements and potentiodynamic polarization studies in 3.5% NaCl solution showed that both deposits have similar properties.

  4. Morphological study of ternary Ni-Cu-P alloys by atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Balaraju, J.N. [Surface Engineering Division, National Aerospace Laboratories, Post Bag No. 1779, Bangalore 560 017 (India)]. E-mail: jnbalaraju@rediffmail.com; Anandan, C. [Surface Engineering Division, National Aerospace Laboratories, Post Bag No. 1779, Bangalore 560 017 (India); Rajam, K.S. [Surface Engineering Division, National Aerospace Laboratories, Post Bag No. 1779, Bangalore 560 017 (India)

    2005-08-31

    Ternary electroless Ni-Cu-P alloy films were deposited by using nickel sulphate (B1)- and nickel chloride (B2)-based alkaline baths. Alloy films were characterized for their structure, morphology, chemical composition and microhardness. A single broad peak was obtained in XRD for both B1 and B2 films and the calculated grain sizes are 1.6 and 1.9 nm, respectively. Optical microscopic examination of the deposited coatings revealed a less nodular structure for B2-based coatings. SEM micrographs showed that films were smooth and nodular. Compositional analysis made on these deposits using EDX and the chemical state identification by XPS showed that the coatings are almost identical. AFM studies showed that the deposits from B2 bath are comparatively smoother with less nodular structure. Microhardness measurements and potentiodynamic polarization studies in 3.5% NaCl solution showed that both deposits have similar properties.

  5. Oxygen-induced Y surface segregation in a CuPdY ternary alloy

    Energy Technology Data Exchange (ETDEWEB)

    Tafen, D N.; Miller, J B.; Dogan, O N.; Baltrus, J P.; Kondratyuk, P

    2013-01-01

    We present a comprehensive theoretical and experimental study of the segregation behavior of the ternary alloy CuPdY in vacuum (i.e., the clean surface) and in the presence of oxygen. Theoretical prediction shows that for clean surface, yttrium will substitute first for Cu and then for Pd at the subsurface lattice site before segregating to the surface where it substitutes for Cu. XRD characterization of the surface of CuPdY indicates the presence of two major phases, B2 CuPd and Pd{sub 3}Y. In the presence of adsorbed oxygen, theory predicts that Y preferentially occupies surface sites due to its stronger oxygen affinity compared to Cu and Pd. XPS experiments confirm the computational results in the adsorbed oxygen case, showing that surface segregation of yttrium is induced by the formation of Y-oxides at the top-surface of the alloy.

  6. The band gap of II-Vi ternary alloys in a tight-binding description

    Energy Technology Data Exchange (ETDEWEB)

    Olguin, Daniel; Blanquero, Rafael [Instituto Politecnico Nacional, Mexico, D.F (Mexico); De Coss, Romeo [Instituto Politecnico Nacional, Yucatan (Mexico)

    2001-02-01

    We present tight-binding calculations for the band gap of II-Vi pseudobinary ternary alloys. We use an sp{sup 3} s* tight-binding Hamiltonian which include spin-orbit coupling. The band gap composition dependence is calculated using a extended version of the virtual crystal approximation, which introduce an empirical correction factor that takes into account the non-linear dependence of the band gap with the composition. The results compare quite well with the experimental data, both for the ternary alloys with wide band gap and for the narrow band gap ones. [Spanish] Presentamos el calculo de la banda de energia prohibida de aleaciones ternarias de compuestos II-VI. El calculo, que incluye interaccion espin-orbita, se hace con el metodo de enlace fuerte, utilizando una base ortogonal de cinco orbitales atomicos por atomo (sp{sup 3} s*), en conjunto con la aproximacion del cristal virtual. En la aproximacion del cristal virtual, incluimos un factor de correccion que toma en cuenta la no linealidad de la banda de energia prohibida como funcion de la concentracion. Con esta correccion nuestros resultados reproducen aceptablemente los datos experimentales hallados en la literatura.

  7. Rapid solidification mechanism of highly undercooled ternary Cu40Sn45Sb15 alloy

    Science.gov (United States)

    Zhai, W.; Wang, B. J.; Lu, X. Y.; Wei, B.

    2015-10-01

    The rapid solidification of ternary Cu40Sn45Sb15 peri-eutectic type alloy was realized by glass fluxing and drop tube methods, and the corresponding maximum undercoolings are 185 K (0.22 T L) and 321 K (0.39 T L), respectively. The phase constitution of Cu40Sn45Sb15 alloy in these two rapid solidification experiments deviates from the two equilibrium phases (Sn + Cu6Sn5). In glass fluxing method, the structural morphology of Cu40Sn45Sb15 alloy is mainly characterized by a three-layer lamellar structure, which is comprised by an inner layer of long strips of primary ɛ(Cu3Sn) phase, an intermediate layer of η(Cu6Sn5) phase and an outer layer of β(SnSb) phase. As undercooling rises, this lamellar structure is remarkably refined. When small alloy droplets are containerlessly solidified during free fall in drop tube, the primary ɛ(Cu3Sn) phase grows by non-faceted mode into dendrites as droplet diameter decreases. Especially, solidification path alters in the smallest droplet with 50 μm diameter, in which η(Cu6Sn5) and Sn3Sb2 phases form directly from the metastable liquid phase by suppressing the primary ɛ phase formation and the following peri-eutectic transformation.

  8. The thermodynamic stability induced by solute co-segregation in nanocrystalline ternary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Tao; Chen, Zheng; Zhang, Jinyong; Zhang, Ping [China Univ. of Mining and Technology, Xuzhou (China). School of Mateial Science and Engineering; Yang, Xiaoqin [China Univ. of Mining and Technology, Xuzhou (China). School of Chemical Engineering and Technology

    2017-06-15

    The grain growth and thermodynamic stability induced by solute co-segregation in ternary alloys are presented. Grain growth behavior of the single-phase supersaturated grains prepared in Ni-Fe-Pb alloy melt at different undercoolings was investigated by performing isothermal annealings at T = 400 C-800 C. Combining the multicomponent Gibbs adsorption equation and Guttmann's grain boundary segregation model, an empirical relation for isothermal grain growth was derived. By application of the model to grain growth in Ni-Fe-Pb, Fe-Cr-Zr and Fe-Ni-Zr alloys, it was predicted that driving grain boundary energy to zero is possible in alloys due to the co-segregation induced by the interactive effect between the solutes Fe/Pb, Zr/Ni and Zr/Cr. A non-linear relationship rather than a simple linear relation between 1/D* (D* the metastable equilibrium grain size) and ln(T) was predicted due to the interactive effect.

  9. Investigations of binary and ternary phase change alloys for future memory applications

    Energy Technology Data Exchange (ETDEWEB)

    Rausch, Pascal

    2012-09-13

    The understanding of phase change materials is of great importance because it enables us to predict properties and tailor alloys which might be even better suitable to tackle challenges of future memory applications. Within this thesis two topics have been approached: on the one hand the understanding of the alloy In{sub 3}Sb{sub 1}Te{sub 2} and on the other hand the so called resistivity drift of amorphous Ge-Sn-Te phase change materials. The main topic covers an in depth discussion of the ternary alloy In{sub 3}Sb{sub 1}Te{sub 2}. At first glance, this alloy does not fit into the established concepts of phase alloys: e.g. the existence of resonant bonding in the crystalline phase is not obvious and the number of p-electrons is very low compared to other phase change alloys. Furthermore amorphous phase change alloys with high indium content are usually not discussed in literature, an exception being the recent work by Spreafico et al. on InGeTe{sub 2}. For the first time a complete description of In{sub 3}Sb{sub 1}Te{sub 2} alloy is given in this work for the crystalline phase, amorphous phase and crystallization process. In addition comparisons are drawn to typical phase change materials like Ge{sub 2}Sb{sub 2}Te{sub 5}/GeTe or prototype systems like AgInTe{sub 2} and InTe. The second topic of this thesis deals with the issue of resistivity drift, i.e. the increase of resistivity of amorphous phase change alloys with aging. This drift effect greatly hampers the introduction of multilevel phase change memory devices into the market. Recently a systematic decrease of drift coefficient with stoichiometry has been observed in our group going from GeTe over Ge{sub 3}Sn{sub 1}Te{sub 4} to Ge{sub 2}Sn{sub 2}Te{sub 4}. These alloys are investigated with respect to constraint theory.

  10. Formation, Characteristics and Electrocatalytic Properties of Nanoporous Metals Formed by Dealloying of Ternary-Noble Alloys

    Science.gov (United States)

    Vega Zuniga, Adrian A.

    Nanoporous metals formed by electrochemical dealloying of silver from Ag-Au-Pt alloys, with 77 at.% silver and platinum contents of 1, 2 and 3 at.%, have been studied. The presence of platinum, which is immobile relative to gold, refine the ligament size and stabilized the nanostructure against coarsening, even under experimental conditions that would be expected to promote coarsening (e.g., exposure to high temperature, longer dealloying times). By adding only 1 at.% Pt to the alloy precursor, the ligament/pore size was reduced by 50% with respect to that in nanoporous gold (NPG), which was formed on a Ag-Au alloy with the same silver content as ternary alloys. A further decrease in the ligament size was observed by increasing the platinum content of the precursor; however, most of the improvement occurred with 1 at.% Pt. The adsorbate-induced surface segregation of platinum was also investigated for these nanoporous metals. By exposing freshly-dealloyed nanostructures to moderate temperatures in the presence of air, platinum segregated to the ligament surface; in contrast, in an inert atmosphere (Ar-H 2), platinum mostly reverted to the bulk of the ligaments. This thermally activated process was thermodynamically driven by the interaction between platinum and oxygen; however, at the desorption temperature of oxygen, platinum de-segregated from the surface. Moreover, the co-segregation of platinum and oxygen hindered the thermal coarsening of the ligaments. Finally, the electrocatalytic abilities of these nanostructures were studied towards methanol and ethanol electro-oxidation, in alkaline and acidic media, showing significantly improved response in comparison to that observed in NPG. The synergistic effect between gold and platinum atoms and the smaller feature size of the nanostructures were directly associated with this behaviour. In alkaline electrolyte, the nanostructure formed on the alloy with 1 at.% Pt showed higher catalytic response than the other two

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

    Science.gov (United States)

    Jolodosky, Alejandra

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

  12. The dynamics of nucleation and growth of a particle in the ternary alloy melt with anisotropic surface tension.

    Science.gov (United States)

    Chen, Ming-Wen; Li, Lin-Yan; Guo, Hui-Min

    2017-08-28

    The dynamics of nucleation and growth of a particle affected by anisotropic surface tension in the ternary alloy melt is studied. The uniformly valid asymptotic solution for temperature field, concentration field, and interface evolution of nucleation and particle growth is obtained by means of the multiple variable expansion method. The asymptotic solution reveals the critical radius of nucleation in the ternary alloy melt and an inward melting mechanism of the particle induced by the anisotropic effect of surface tension. The critical radius of nucleation is dependent on isotropic surface tension, temperature undercooling, and constitutional undercooling in the ternary alloy melt, and the solute diffusion melt decreases the critical radius of nucleation. Immediately after a nucleus forms in the initial stage of solidification, the anisotropic effect of surface tension makes some parts of its interface grow inward while some parts grow outward. Until the inward melting attains a certain distance (which is defined as "the melting depth"), these parts of interface start to grow outward with other parts. The interface of the particle evolves into an ear-like deformation, whose inner diameter may be less than two times the critical radius of nucleation within a short time in the initial stage of solidification. The solute diffusion in the ternary alloy melt decreases the effect of anisotropic surface tension on the interface deformation.

  13. Distribution of nickel after modified nitinol stent implantation in animals

    Science.gov (United States)

    Chepeleva, E.; Sergeevichev, D.; Lotkov, A.; Kashin, O.; Korobeynikov, A.; Kozyr, K.; Baystrukov, V.; Zubarev, D.; Kretov, E.; Pokushalov, E.

    2017-09-01

    Intravascular stenting of arteries in atherosclerotic lesions is one of the most frequently performed procedures in cardiovascular surgery today. Most stents are made of various stainless-steel alloys and other metals (such as nitinol). Nitinol is a biocompatible, superplastic and corrosion resistant material with an important feature of shape memory. However, the composition of this alloy includes nickel, which shows toxicity to the kidneys, liver, lungs, heart and other organs when it accumulates in the organism. In this research we investigated the nickel content in serum, urine and hair of the laboratory animals after implantation of nitinol stents treated with plasma ionic surface modification by silicon.

  14. Onset of Hot Tearing in Ternary Mg-Al-Sr Alloy Castings

    Science.gov (United States)

    Cao, G.; Haygood, I.; Kou, S.

    2010-08-01

    Ternary Mg-Al-Sr alloys are the base of a few new creep-resistant, lightweight Mg alloys for automobiles. Hot tearing of Mg-Al-Sr alloys was studied by constrained rod casting (CRC) in a steel mold equipped with a load cell and a thermocouple. The alloys investigated included, in order of decreasing hot tearing susceptibility, Mg-4Al-1.5Sr, Mg-6Al-1.5Sr, Mg-8Al-1.5Sr, and Mg-8Al-3Sr. Two different molds were used, one for 8.7-mm-diameter rods and the other 7.9 mm. The cooling rate was varied by varying mold preheating from 523 K (250 °C) to 658 K (385 °C) and mold insulation. The load curve showed a clear peak when hot tearing occurred in all but Mg-8Al-3Sr due to its high resistance to hot tearing. From the peak and the cooling curve, the temperature at which hot tearing occurred was determined and found to decrease with increasing Al content from 4 to 8 pct. For a specific alloy, the hot tearing onset temperature did not change significantly with the rod diameter or mold preheating, at least within the experimental conditions used. The Scheil solidification model was used to estimate the fraction solid at the onset of hot tearing. It was found that hot tearing occurred near the end of primary solidification L → α (Mg) and that the fraction solid at which hot tearing occurred decreased with increasing Al content. The validity of the Scheil model was discussed.

  15. Sn-Sb-Se based binary and ternary alloys for phase change memory applications

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Kyung-Min

    2008-10-28

    In this work, the effect of replacing Ge by Sn and Te by Se was studied for a systematic understanding and prediction of new potential candidates for phase change random access memories applications. The temperature dependence of the electrical/structural properties and crystallization kinetics of the Sn-Se based binary and Sn-Sb-Se based ternary alloys were determined and compared with those of the GeTe and Ge-Sb-Te system. The temperature dependence of electrical and structural properties were investigated by van der Pauw measurements, X-ray diffraction, X-ray reflectometry. By varying the heating rate, the Kissinger analysis has been used to determine the combined activation barrier for crystallization. To screen the kinetics of crystallization, a static laser tester was employed. In case of binary alloys of the type Sn{sub x}Se{sub 1-x}, the most interesting candidate is SnSe{sub 2} since it crystallizes into a single crystalline phase and has high electrical contrast and reasonably high activation energy for crystallization. In addition, the SnSe{sub 2}-Sb{sub 2}Se{sub 3} pseudobinary alloy system also might be sufficient for data retention due to their higher transition temperature and activation energy for crystallization in comparison to GeTe-Sb{sub 2}Te{sub 3} system. Furthermore, SnSe{sub 2}-Sb{sub 2}Se{sub 3} pseudobinary alloys have a higher crystalline resistivity. The desired rapid crystallization speed can be obtained for Sn{sub 1}Sb{sub 2}Se{sub 5} and Sn{sub 2}Sb{sub 2}Se{sub 7} alloys. (orig.)

  16. Solute redistribution during phase separation of ternary Fe-Cu-Si alloy

    Science.gov (United States)

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

    2015-06-01

    Ternary Fe48Cu48Si4 immiscible alloy was rapidly solidified under the containerless microgravity condition inside a drop tube. Liquid phase separation took place in the alloy melt and led to the formation of various segregated structures. The core-shell structure consisting of Fe-rich and Cu-rich zones and the homogenously dispersed structure were the major structural morphologies. Phase field simulation results revealed that the two-layer core-shell was the final structure of liquid phase separation. The solute redistribution of liquid Fe48Cu48Si4 alloy experienced the macroscopic solute distribution induced by liquid phase separation, the secondary phase separation within the separated liquid phases and the solute trapping during rapid solidification. Energy dispersive spectroscopy analysis showed that the solute Si was enriched in the Fe-rich zone whereas depleted in the Cu-rich zone. In addition, both αFe and (Cu) phases in the Fe-rich zone exhibited a conspicuous solute trapping effect. As compared with (Cu) phase, αFe phase had a stronger affinity with solute Si.

  17. Ternary Sn-Sb-Co alloy film as new negative electrode for lithium-ion cells

    Energy Technology Data Exchange (ETDEWEB)

    Tabuchi, T. [Institute for Chemical Technology of Inorganic Materials, Technical University of Graz, Stremayrgasse 16, Graz 8010 (Austria); Graduate School of Engineering, Kyoto University, Kyotodaigaku-katsura, Nishikyo-ku, Kyoto 615-8510 (Japan); Hochgatterer, N.; Winter, M. [Institute for Chemical Technology of Inorganic Materials, Technical University of Graz, Stremayrgasse 16, Graz 8010 (Austria); Ogumi, Z. [Graduate School of Engineering, Kyoto University, Kyotodaigaku-katsura, Nishikyo-ku, Kyoto 615-8510 (Japan)

    2009-03-15

    Ternary Sn-Sb-Co alloy film was successfully prepared by the co-electroplating method using an aqueous solution bath containing SnCl{sub 2}.2H{sub 2}O, CoCl{sub 2}, SbCl{sub 3}, Na{sub 2}C{sub 4}H{sub 4}O{sub 6}.2H{sub 2}O, K{sub 3}C{sub 6}H{sub 5}O{sub 7}.H{sub 2}O, and gelatine. The alloy composition was found to be mainly controllable by the amount of Na{sub 2}C{sub 4}H{sub 4}O{sub 6}.2H{sub 2}O and SbCl{sub 3} in the plating bath. The Sn-Sb-Co film electrode with a composition of 75.4% Sn, 6.5% Sb, and 18.1% Co gave an initial discharge capacity of 380 mAh g{sup -1}. The capacity gradually increased from the 1st to the 10th cycle and was then stabilized at a larger value of 580 mAh g{sup -1}. Furthermore, the electrode was found to give better cycle performance compared to binary Sn-Co and Sn-Sb alloys. (author)

  18. 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.

  19. Ternary Bi-Cu-Ni alloys – thermodynamics, characterization, mechanical and electrical properties

    Directory of Open Access Journals (Sweden)

    Branislav Radomir Marković

    2017-09-01

    Full Text Available The Bi–Cu–Ni ternary system belongs to the group of potential Cu-Ni-based advanced lead-free solder materials for high temperature application. The paper shows results of the thermodynamic calculations using general solution model along the line with the molar ratio of Cu: Ni = 1:1. The experimental part shows thermal, structural, electrical and mechanical properties based on differential scanning calorimetry (DSC, scanning electron microscopy with energy dispersive spectrometry (SEM-EDS, electroconductivity and hardness measurements of the alloys selected in the section from bismuth corner with molar ratio Cu: Ni = 1:1, Cu: Ni = 3:1, and Cu: Ni = 1:3.

  20. Determination of thermodynamic properties of aluminum based binary and ternary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Altıntas, Yemliha [Abdullah Gül University, Faculty of Engineering, Department of Materials Science and Nanotechnology, 38039, Kayseri (Turkey); Aksöz, Sezen [Nevşehir Hacı Bektaş Veli University, Faculty of Arts and Science, Department of Physics, 50300, Nevşehir (Turkey); Keşlioğlu, Kâzım, E-mail: kesli@erciyes.edu.tr [Erciyes University, Faculty of Science, Department of Physics, 38039, Kayseri (Turkey); Maraşlı, Necmettin [Yıldız Technical University, Faculty of Chemical and Metallurgical Engineering, Department of Metallurgical and Materials Engineering, 34210, Davutpaşa, İstanbul (Turkey)

    2015-11-15

    In the present work, the Gibbs–Thomson coefficient, solid–liquid and solid–solid interfacial energies and grain boundary energy of a solid Al solution in the Al–Cu–Si eutectic system were determined from the observed grain boundary groove shapes by measuring the thermal conductivity of the solid and liquid phases and temperature gradient. Some thermodynamic properties such as the enthalpy of fusion, entropy of fusion, the change of specific heat from liquid to solid and the electrical conductivity of solid phases at their melting temperature were also evaluated by using the measured values of relevant data for Al–Cu, Al–Si, Al–Mg, Al–Ni, Al–Ti, Al–Cu–Ag, Al–Cu–Si binary and ternary alloys. - Highlights: • The microstructure of the Al–Cu–Si eutectic alloy was observed through SEM. • The three eutectic phases (α-Al, Si, CuAl{sub 2}) have been determined by EDX analysis. • Solid–liquid and solid–solid interfacial energies of α-Al solution were determined. • ΔS{sub f},ΔH{sub M}, ΔC{sub P}, electrical conductivity of solid phases for solid Al solutions were determined. • G–T coefficient and grain boundary energy of solid Al solution were determined.

  1. Liquid-liquid phase separation of freely falling undercooled ternary Fe-Cu-Sn alloy

    Science.gov (United States)

    Wang, W. L.; Wu, Y. H.; Li, L. H.; Zhai, W.; Zhang, X. M.; Wei, B.

    2015-11-01

    The active modulation and control of the liquid phase separation for high-temperature metallic systems are still challenging the development of advanced immiscible alloys. Here we present an attempt to manipulate the dynamic process of liquid-liquid phase separation for ternary Fe47.5Cu47.5Sn5 alloy. It was firstly dispersed into numerous droplets with 66 ~ 810 μm diameters and then highly undercooled and rapidly solidified under the containerless microgravity condition inside drop tube. 3-D phase field simulation was performed to explore the kinetic evolution of liquid phase separation. Through regulating the combined effects of undercooling level, phase separation time and Marangoni migration, three types of separation patterns were yielded: monotectic cell, core shell and dispersive structures. The two-layer core-shell morphology proved to be the most stable separation configuration owing to its lowest chemical potential. Whereas the monotectic cell and dispersive microstructures were both thermodynamically metastable transition states because of their highly active energy. The Sn solute partition profiles of Fe-rich core and Cu-rich shell in core-shell structures varied only slightly with cooling rate.

  2. Liquid-liquid phase separation of freely falling undercooled ternary Fe-Cu-Sn alloy

    Science.gov (United States)

    Wang, W .L.; Wu, Y. H.; Li, L. H.; Zhai, W.; Zhang, X. M.; Wei, B.

    2015-01-01

    The active modulation and control of the liquid phase separation for high-temperature metallic systems are still challenging the development of advanced immiscible alloys. Here we present an attempt to manipulate the dynamic process of liquid-liquid phase separation for ternary Fe47.5Cu47.5Sn5 alloy. It was firstly dispersed into numerous droplets with 66 ~ 810 μm diameters and then highly undercooled and rapidly solidified under the containerless microgravity condition inside drop tube. 3-D phase field simulation was performed to explore the kinetic evolution of liquid phase separation. Through regulating the combined effects of undercooling level, phase separation time and Marangoni migration, three types of separation patterns were yielded: monotectic cell, core shell and dispersive structures. The two-layer core-shell morphology proved to be the most stable separation configuration owing to its lowest chemical potential. Whereas the monotectic cell and dispersive microstructures were both thermodynamically metastable transition states because of their highly active energy. The Sn solute partition profiles of Fe-rich core and Cu-rich shell in core-shell structures varied only slightly with cooling rate. PMID:26552711

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

    Directory of Open Access Journals (Sweden)

    Minic, Duško M.

    2015-06-01

    Full Text Available Structural, mechanical and electrical properties of selected alloys in ternary Ag-Bi-Zn system are presented in this paper. Chosen alloys were investigated using X-Ray Diffraction (XRD, light optical microscopy, Scanning Electron Microscopy combined with Energy Dispersive Spectrometry (SEM-EDS, as well as by electrical conductivity and Brinell hardness measurements. Isolines of electrical conductivity and hardness for the entire Ag-Bi-Zn system were calculated using regression models.Este trabajo estudia las propiedades estructurales, mecánicas y eléctricas de aleaciones seleccionadas del sistema ternario Ag-Bi-Zn. Las aleaciones elegidas se han caracterizado por medio de difracción de rayos X, microscopía óptica, microscopía electrónica de barrido combinada con espectrometría de dispersión de energía, así como por medio de medidas de conductividad eléctrica y dureza Brinell. Por medio de modelos de regresión se han calculado las líneas de isoconductividad eléctrica y dureza para todo el sistema Ag-Bi-Zn.

  4. Contribution to the Study of the Relation between Microstructure and Electrochemical Behavior of Iron-Based FeCoC Ternary Alloys

    Directory of Open Access Journals (Sweden)

    Farida Benhalla-Haddad

    2012-01-01

    Full Text Available This work deals with the relation between microstructure and electrochemical behavior of four iron-based FeCoC ternary alloys. First, the arc-melted studied alloys were characterized using differential thermal analyses and scanning electron microscopy. The established solidification sequences of these alloys show the presence of two primary crystallization phases (δ(Fe and graphite as well as two univariante lines : peritectic L+(Fe↔(Fe and eutectic L↔(Fe+Cgraphite. The ternary alloys were thereafter studied in nondeaerated solution of 10−3 M NaHCO3 + 10−3 M Na2SO4, at 25°C, by means of the potentiodynamic technique. The results indicate that the corrosion resistance of the FeCoC alloys depends on the carbon amount and the morphology of the phases present in the studied alloys.

  5. Contribution to the Study of the Relation between Microstructure and Electrochemical Behavior of Iron-Based FeCoC Ternary Alloys

    Science.gov (United States)

    Benhalla-Haddad, Farida; Amara, Sif Eddine; Benchettara, Abdelkader; Taibi, Kamel; Kesri, Rafika

    2012-01-01

    This work deals with the relation between microstructure and electrochemical behavior of four iron-based FeCoC ternary alloys. First, the arc-melted studied alloys were characterized using differential thermal analyses and scanning electron microscopy. The established solidification sequences of these alloys show the presence of two primary crystallization phases (δ(Fe) and graphite) as well as two univariante lines : peritectic L + δ(Fe)↔γ(Fe) and eutectic L↔γ(Fe) + Cgraphite. The ternary alloys were thereafter studied in nondeaerated solution of 10−3 M NaHCO3 + 10−3 M Na2SO4, at 25°C, by means of the potentiodynamic technique. The results indicate that the corrosion resistance of the FeCoC alloys depends on the carbon amount and the morphology of the phases present in the studied alloys. PMID:22448342

  6. The structure and physical properties of CuMPd{sub 6} (M = Ti, V, Mn and Fe) ternary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ziya, A.B. [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan)], E-mail: amerziya@gmail.com; Takahashi, M.; Ohshima, K. [Institute of Materials Science, University of Tsukuba, Tsukuba 305-8573 (Japan)

    2009-06-24

    In situ X-ray diffraction and magnetic susceptibility measurements were performed to determine the structure, thermal and magnetic properties of the ternary alloys CuMPd{sub 6} (M = Ti, V, Mn and Fe). The X-ray diffraction experiments of the polycrystalline specimens annealed at 1273 K have shown that a single phase (A1-type face-centered cubic (fcc) structure) is formed at this stoichiometric composition up to a temperature of 1178 K. The integrated intensity data obtained from the diffraction experiments were utilized to determine the lattice parameters, Debye temperatures ({theta}{sub D}), the mean linear thermal expansion (MLTE) and the coefficients of thermal expansion ({alpha}(T)). The lattice parameters showed a positive deviation from the Vegard's law, whereas the Debye temperatures were found to be of the same order as for CuPd{sub 3} alloy. The contribution of the static displacements to the temperature factors was found to be nearly zero for the four alloys. The linear thermal expansion follows the classical Grueneisen relationship in these alloys. The trend of magnetic properties in these alloys was observed to be similar to that for CuMPt{sub 6} alloys (see text) i.e. paramagnetic - spin glass - ferromagnetic with the increasing atomic number of the metal M. The results have been discussed by comparing with those given in literature.

  7. Tunable fluorescence emission of ternary nonstoichiometric Ag-In-S alloyed nanocrystals

    Science.gov (United States)

    Feng, Jian; Yang, Xiurong

    2012-08-01

    Low toxic, nonstoichiometric colloidal Ag-In-S ternary quantum dots with different Ag content were synthesized by a one-pot hot-injection method based on the reaction of metal acetylacetonates with sulfur dissolved in octadecene. X-ray diffraction (XRD), transmission electron microscopy, and high-resolution transmission electron microscopy (HRTEM) were used to characterize the size, structure, and morphology of these samples. ICP-MS was employed to analyze the compositions of Ag-In-S nanocrystals. The optical properties were characterized by UV-Vis absorption, photoluminescence (PL) spectroscopy, and time-resolved photoluminescence. Varying the fraction of cationic and capping agents, the compositions of Ag-In-S nanocrystals were precisely controlled. XRD and HRTEM results indicate the compositional homogeneity of Ag-In-S. The emission spectra across the different compositions exhibiting a single bandgap feature further confirm the formation of Ag-In-S alloy NCs, rather than phase separated Ag2S and In2S3. Composition-dependent tunable PL emissions have been observed. The relative PL quantum yield is up to 16 %, which exhibited substantially enhanced comparing with the stoichiometric AgInS2 semiconductor core QDs reported in previous literature. The PL decay curve of Ag-In-S has a biexponential characteristic, which indicates that the recombination of an electron and a hole is dominated by the surface defect and the recombination process associated with internal traps is reduced significantly. The large Stokes shift between the absorption peaks and their emissions should inhibit the reabsorption and Förster energy transfer between Ag-In-S nanocrystals, which provides the alternative in the further applications where high-concentrations of nanocrystals are needed.

  8. Fullerene alloy formation and the benefits for efficient printing of ternary blend organic solar cells

    DEFF Research Database (Denmark)

    Angmo, Dechan; Bjerring, Morten; Nielsen, Niels Chr.

    2015-01-01

    with a third polymer component, the system exhibits pseudo-binary phase behaviour instead of the expected ternary phase behaviour. Our results experimentally confirm the earlier hypothesis that the unexpected composition average dependent IV-behaviour for these supposed ternary mixtures are indeed due to them...

  9. Neutronics Evaluation of Lithium-Based Ternary Alloys in IFE Blankets

    Energy Technology Data Exchange (ETDEWEB)

    Jolodosky, A. [Univ. of California, Berkeley, CA (United States); Fratoni, M. [Univ. of California, Berkeley, CA (United States)

    2015-09-22

    , low electrical conductivity and therefore low MHD pressure drop, low chemical reactivity, and extremely low tritium inventory; the addition of sodium (FLiNaBe) has been considered because it retains the properties of FliBe but also lowers the melting point. Although many of these blanket concepts are promising, challenges still remain. The limited amount of beryllium available poses a problem for ceramic breeders such as the HCPB. FLiBe and FLiNaBe are highly viscous and have a low thermal conductivity. Lithium lead possesses a poor thermal conductivity which can cause problems in both DCLL and LiPb blankets. Additionally, the tritium permeation from these two blankets into plant components can be a problem and must be reduced. Consequently, Lawrence Livermore National Laboratory (LLNL) is attempting to develop a lithium-based alloy—most likely a ternary alloy—which maintains the beneficial properties of lithium (e.g. high tritium breeding and solubility) while reducing overall flammability concerns for use in the blanket of an inertial fusion energy (IFE) power plant. The LLNL concept employs inertial confinement fusion (ICF) through the use of lasers aimed at an indirect-driven target composed of deuterium-tritium fuel. The fusion driver/target design implements the same physics currently experimented at the National Ignition Facility (NIF). The plant uses lithium in both the primary coolant and blanket; therefore, lithium-related hazards are of primary concern. Although reducing chemical reactivity is the primary motivation for the development of new lithium alloys, the successful candidates will have to guarantee acceptable performance in all their functions. The scope of this study is to evaluate the neutronics performance of a large number of lithium-based alloys in the blanket of the IFE engine and assess their properties upon activation. This manuscript is organized as follows: Section 12 presents the models and methodologies used for the analysis; Section

  10. Investigation Of Interaction Between Nitinol Stent And A Vascular Plaque Using Finite Element Method

    Directory of Open Access Journals (Sweden)

    Recep Güneş

    2012-06-01

    Full Text Available In this study, the interaction between the Nitinol stent and the artery with plaque was investigated using finite element method. The occurring pressure values during the cardiac contraction (systolic and loosening (diastolic were applied as loading to the modeled system with Nitinol stent. In the light of the stress values, the suitability of the Nitinol stent in an artery with plaque was investigated. In the analysis, Nitinol stent was assumed to be shape memory alloy, and artery and plaque were assumed to behave linearly elastic. As a result, the stress and deformations in the plaque and artery due to the interference of Nitinol stent were discussed and concluded that the structure of artery with plaque can be expanded in accordance with Nitinol stent.

  11. Quantum chemical analysis of binary and ternary ferromagnetic alloys; Quantenchemische Untersuchungen binaerer und ternaerer ferromagnetischer Legierungen

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, Yasemin Erika Charlotte

    2007-02-23

    In this work the electronic structures, densities of states, chemical bonding, magnetic exchange Parameters and Curie temperatures of binary and ternary ferromagnetic alloys are analyzed. The electronic structure of ferromagnetic MnAl has been calculated using density-functional techniques (TB-LMTO-ASA, FPLAPW) and quantum chemically analyzed by means of the crystal orbital Hamilton population analysis. The crystal structure of the ferromagnetic tetragonal MnAl may be understood to originate from the structure of nonmagnetic cubic MnAl with a CsCl motif through a two-step process. While the nonmagnetic cubic structure is stable against a structural deformation, antibonding Mn-Mn interactions at the Fermi level lead to spin polarization and the onset of magnetism, i.e., a symmetry reduction taking place solely in the electronic degrees of freedom, by that emptying antibonding Mn-Mn states. Residual antibonding Al--Al states can only be removed by a subsequent, energetically smaller structural deformation towards the tetragonal system. As a final result, homonuclear bonding is strengthened and heteronuclear bonding is weakened. Corresponding DFT calculations of the electronic structure as well as the calculation of the chemical bonding and the magnetic exchange interactions have been performed on the basis of LDA and GGA for a series of ferromagnetic full Heusler alloys of general formula Co2MnZ (Z=Ga,Si,Ge,Sn), Rh2MnZ (Z=Ge,Sn,Pb), Ni2MnZ (Z=Ga,In,Sn), Pd2MnZ (Z=Sn,Sb) and Cu2MnZ (Z=Al,In,Sn). The connection between the electronic spectra and the magnetic interactions have been studied. Correlations between the chemical bondings in Heusler alloys derived from COHP analysis and magnetic phenomena are obvious, and different mechanisms leading to spin polarization and ferromagnetism are derived. The band dependence of the exchange parameters, their dependence on volume and valence electron concentration have been thoroughly analyzed within the Green function technique

  12. X-ray diffraction study of the structure and thermal parameters of the ternary Au-Ag-Pd alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ziya, A.B. [Department of Physics, Bahauddin Zakariya University, Multan-60800 (Pakistan) and Institute of Materials Science, University of Tsukuba, Tsukuba 305-8573 (Japan)]. E-mail: amer_ziya@yahoo.com; Ohshima, K. [Institute of Materials Science, University of Tsukuba, Tsukuba 305-8573 (Japan)

    2006-11-30

    In situ X-ray diffraction experiments were performed on six samples of the ternary Au-Ag-Pd alloys (with A1 structure) having different compositions using a Cu-target. The integrated intensity data obtained in the temperature range of 373-1200K was utilized to determine the lattice parameters and the thermal parameters like Einstein's temperatures ({theta}{sub E}), the mean-square amplitudes (u{sup 2}-bar (T)) and the coefficients of thermal expansion with a high accuracy. The lattice parameter showed a small negative deviation from the Vegard's rule. It is also found that the mean-square amplitudes are independent of the static displacements. The mean-square amplitudes of vibration and the linear thermal expansion follow the classical Gruneisen relationship in these alloys.

  13. Toward Multi Principal Component Alloy Discovery: Assessment of the CALPHAD Approach for Ternary (Preprint)

    Science.gov (United States)

    2016-09-15

    phase names such as “ sigma ” or “r- phase ” were disregarded. Of the ternaries evaluated, 14% of the systems have a phase that is only present with a...principal element systems. However, the uncertainty of phase equilibria predictions within these regions is unknown. This study assesses the current...capabilities of a commercially available CALPHAD databases to accurately predict phase equilibria within ternary phase space as a function of the number

  14. Study on the Mg-Li-Zn ternary alloy system with improved mechanical properties, good degradation performance and different responses to cells

    NARCIS (Netherlands)

    Liu, Yang; Wu, Yuanhao; Bian, Dong; Gao, Shuang; Leeflang, M.A.; Guo, Hui; Zheng, Yufeng; Zhou, J.

    2017-01-01

    Novel Mg-(3.5, 6.5wt%)Li-(0.5, 2, 4wt%)Zn ternary alloys were developed as new kinds of biodegradable metallic materials with potential for stent application. Their mechanical properties, degradation behavior, cytocompatibility and hemocompatibility were studied. These potential biomaterials

  15. Nanoassembly of Polydisperse Photonic Crystals based on Binary and Ternary Polymer Opal Alloys

    CERN Document Server

    Zhao, Qibin; Schafer, Christian; Spahn, Peter; Gallei, Markus; Herrmann, Lars; Petukhov, Andrei; Baumberg, Jeremy J

    2016-01-01

    Ordered binary and ternary photonic crystals, composed of different sized polymer-composite spheres with diameter ratios up to 120%, are generated using bending induced oscillatory shearing (BIOS). This viscoelastic system creates polydisperse equilibrium structures, producing mixed opaline colored films with greatly reduced requirements for particle monodispersity, and very different sphere size ratios, compared to other methods of nano-assembly.

  16. Laparoscopic Inguinal Hernia Repair With a Novel Hernia Mesh Incorporating a Nitinol Alloy Frame Compared With a Standard Lightweight Polypropylene Mesh.

    Science.gov (United States)

    Bower, Curtis; Hazey, Jeffrey W; Jones, Edward L; Perry, Kyle A; Davenport, Daniel L; Roth, J Scott

    2015-10-01

    Numerous mesh materials are available for laparoscopic inguinal hernia repair. The role of fixation of mesh in laparoscopic inguinal hernia repair remains controversial. Mesh materials have been engineered to anatomically conform to the pelvis to potentially reduce or eliminate the need for fixation. This study evaluates the outcomes of laparoscopic inguinal hernia utilizing a device consisting of a lightweight polypropylene mesh with a nitinol frame (Rebound HRD) compared with repair with lightweight polypropylene mesh with permanent tack fixation. A prospective randomized trial evaluating the outcomes of laparoscopic inguinal hernia repair with a lightweight polypropylene mesh with a nitinol frame (N-LWM) compared with standard lightweight polypropylene mesh (LWM) was conducted. Randomization was performed at an N-LWM to LWM ratio of 2:1. Repairs were standardized to a laparoscopic extraperitoneal approach without fixation for N-LWM and titanium tack fixation for LWM repairs. Follow-up assessments were performed at 7 days, 6 months, and 1 year. Outcome measures include visual analog pain scale (VAS), Short Form 36 (SF-36), Carolinas Comfort Scale (CCS), operative details, complications, and recurrences. There were 47 patients that underwent laparoscopic inguinal hernia repair and adhered to study protocol (31 N-LWM, 16 LWM). The groups did not differ significantly in age, body mass index, ethnicity, or employment. The N-LWM group had bilateral mesh placed in 51.6% and LWM 43.8% (P = .76). Operative duration was similar, 59.6 ± 23.1 minutes for LWM and 62.4 ± 26.7 minutes for N-LWM (P = .705) as was mesh handling time was 5.4 ± 3.1 minutes LWM versus 7.3 ± 3.9 minutes N-LWM (P = .053). VAS, CCS, and SF-36 survey results were similar between groups. There was one recurrence (0.03%) in the N-LWM group. Nitinol-framed lightweight polypropylene mesh may be safely used during laparoscopic inguinal hernia repair with outcomes comparable to LWM at 1 year. N-LWM does

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

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Amanda [Pall Corporation, Port Washington, NY (United States); Zhao, Hongbin [Pall Corporation, Port Washington, NY (United States); Hopkins, Scott [Pall Corporation, Port Washington, NY (United States)

    2014-12-01

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

  18. Electronic properties of GaP{sub x}As{sub 1-x} ternary alloy: A first-principles study

    Energy Technology Data Exchange (ETDEWEB)

    Abdollahi, Arash, E-mail: arash_abdollahi60@yahoo.com; Golzan, Mir Maqsood, E-mail: m.golzan@urmia.ac.ir; Aghayar, Korosh, E-mail: k.aghayar@urmia.ac.ir

    2016-08-05

    The electronic properties of GaP{sub x}As{sub 1-x} ternary semiconductor alloy including effective band structures, density of states and effective masses were studied from first principles using supercell (SC) approach. The modified Becke–Johnson (MBJ) exchange potential together with correlation part of both the local density approximation (LDA) and M06 of Minnesota functionals were used to obtain accurate band structure profile. The effective band structures of alloys were calculated using spectral weight approach and composition dependence of the fundamental gap energy and electron effective masses were estimated from it. The results of the supercell calculations for energy gap and bowing parameters for both direct and indirect gaps are in good agreement with the experiments. The results also show that crossover point of (Γ-Γ) direct and (Γ-x) indirect gap energies occurs at x = 0.46, which is in excellent agreement with the experiments. Furthermore, our results show that the combination of MBJ exchange and M06 correlation potential can be used to estimate accurate band structure profile for GaP, GaAs and their alloys. - Highlights: • The spectral weight approach is applied to the band structure of GaP{sub x}As{sub 1-x}. • Composition dependence of the gap energy and effective masses were estimated. • Crossover point of direct and indirect gap, and bowing parameters were determined. • MBJ-M06 potential leads to accurate band structure for GaP, GaAs and their alloys.

  19. Ordering transitions of ternary alloys A(1-x)B(x)C

    Science.gov (United States)

    Newman, Kathie E.; Shen, Jun

    Alloys of the form A(1-x)B(x)C may form ordered structures for special values of the composition x. This possibility was investigated by considering alloys that have in their disordered high temperature form the zincblende crystal structure. That is, compounds that have a tetrahedral bonding of the type sp3, e.g., alloys of III-V compounds, II-VI compounds (including the diluted magnetic semiconductors), and alloys that are mixtures of the natural chalcopyrites (e.g., II-IV-V sub 2 compounds such as ZnGeAs2) with natural zincblende-structure materials were considered. Possible ordered forms of the alloys A(1-x)B(x)C include, for x = 0.5, a superlattice structure of alternating layers ACBC oriented along the (001) axis, such as was seen in the III-V compound GaAlAs2. Alternatively, for x = 0.5, alloys A(1-x)B(x)C may order in a low temperature phase as an ABC2 chalcopyrite structure, e.g., ZnGeAs2. The question of the relative stabilities of the possible ordered and disordered phases of A(1-x)B(x)C compounds was addressed by using the Kikuchi approximation. The calculations include chemical energies as well as the strain effects. Calculated phase diagrams are shown that exhibit the ordered phases of this type of alloy.

  20. Existence or absence of bandgap bowing in II-VI ternary alloys: Comparison between common-anion and common-cation cases

    Science.gov (United States)

    Tit, Nacir; Obaidat, I. M.; Reshak, A. H.; Alawadhi, H.

    2010-02-01

    The common-anion and common-cation II-VI ternary alloys of the family Cd(Zn)Se(Te) are theoretically investigated based on two different methods. Within the virtual-crystal approximation (VCA), both the sp3s*-tight-binding method, with the inclusion of spin-orbit coupling, and the first-principle full-potential linear augmented plane waves (FP-LAPW) technique are employed to determine the alloy constituents' charge states (ionicities) and degree of bond polarity. The results show that: (i) in the common-cation ternary alloys (i.e., CdSexTe1-x and ZnSexTe1-x), the anions alter a strong competition in trapping more charge. Such a competition builds up a compromised effect yielding the bowing behaviour. Whereas, (ii) in the common-anion ternary alloys (i.e., CdyZn1-yTe and CdyZn1-ySe), the absence of such competition would cause the complete absence of bandgap bowing behaviour. The variation of the bandgap is found to be rather close to linear. The obtained good agreement between our theoretical results and the recently available photoluminescence data does further corroborate our claims.

  1. Lattice Thermal Conductivity of the Binary and Ternary Group-IV Alloys Si-Sn, Ge-Sn, and Si-Ge-Sn

    Science.gov (United States)

    Khatami, S. N.; Aksamija, Z.

    2016-07-01

    Efficient thermoelectric (TE) energy conversion requires materials with low thermal conductivity and good electronic properties. Si-Ge alloys, and their nanostructures such as thin films and nanowires, have been extensively studied for TE applications; other group-IV alloys, including those containing Sn, have not been given as much attention as TEs, despite their increasing applications in other areas including optoelectronics. We study the lattice thermal conductivity of binary (Si-Sn and Ge-Sn) and ternary (Si-Ge-Sn) alloys and their thin films in the Boltzmann transport formalisms, including a full phonon dispersion and momentum-dependent boundary-roughness scattering. We show that Si-Sn alloys have the lowest conductivity (3 W /mK ) of all the bulk alloys, more than 2 times lower than Si-Ge, attributed to the larger difference in mass between the two constituents. In addition, we demonstrate that thin films offer an additional reduction in thermal conductivity, reaching around 1 W /mK in 20-nm-thick Si-Sn, Ge-Sn, and ternary Si-Ge-Sn films, which is near the conductivity of amorphous SiO2 . We conclude that group-IV alloys containing Sn have the potential for high-efficiency TE energy conversion.

  2. Solid-state reactions during mechanical alloying of ternary Fe–Al–X (X=Ni, Mn, Cu, Ti, Cr, B, Si) systems: A review

    Energy Technology Data Exchange (ETDEWEB)

    Hadef, Fatma, E-mail: hadef77@yahoo.fr [Laboratoire de Recherche sur la Physico-Chimie des Surfaces et Interfaces, LRPCSI, Université 20 Août 1955, BP 26, Route d’El-Haddaiek, Skikda 21000 (Algeria); Département de Physique, Faculté des Sciences, Université 20 Août 1955, BP 26, Route d’El-Haddaiek, Skikda 21000 (Algeria)

    2016-12-01

    The last decade has witnessed an intensive research in the field of nanocrystalline materials due to their enhanced properties. A lot of processing techniques were developed in order to synthesis these novel materials, among them mechanical alloying or high-energy ball milling. In fact, mechanical alloying is one of the most common operations in the processing of solids. It can be used to quickly and easily synthesize a variety of technologically useful materials which are very difficult to manufacture by other techniques. One advantage of MA over many other techniques is that is a solid state technique and consequently problems associated with melting and solidification are bypassed. Special attention is being paid to the synthesis of alloys through reactions mainly occurring in solid state in many metallic ternary Fe–Al–X systems, in order to improve mainly Fe–Al structural and mechanical properties. The results show that nanocrystallization is the common result occurring in all systems during MA process. The aim of this work is to illustrate the uniqueness of MA process to induce phase transformation in metallic Fe–Al–X (X=Ni, Mn, Cu, Ti, Cr, B, Si) systems. - Highlights: • A review of state of the art on binary Fe–Al alloys was presented. • Structural and microstructural properties of MA ternary Fe–Al–X alloys were summerized. • MA process is a powerful tool for producing metallic alloys at the nanometer scale.

  3. Study on the Mg-Li-Zn ternary alloy system with improved mechanical properties, good degradation performance and different responses to cells.

    Science.gov (United States)

    Liu, Yang; Wu, Yuanhao; Bian, Dong; Gao, Shuang; Leeflang, Sander; Guo, Hui; Zheng, Yufeng; Zhou, Jie

    2017-10-15

    Novel Mg-(3.5, 6.5wt%)Li-(0.5, 2, 4wt%)Zn ternary alloys were developed as new kinds of biodegradable metallic materials with potential for stent application. Their mechanical properties, degradation behavior, cytocompatibility and hemocompatibility were studied. These potential biomaterials showed higher ultimate tensile strength than previously reported binary Mg-Li alloys and ternary Mg-Li-X (X=Al, Y, Ce, Sc, Mn and Ag) alloys. Among the alloys studied, the Mg-3.5Li-2Zn and Mg-6.5Li-2Zn alloys exhibited comparable corrosion resistance in Hank's solution to pure magnesium and better corrosion resistance in a cell culture medium than pure magnesium. Corrosion products observed on the corroded surface were composed of Mg(OH) 2 , MgCO 3 and Ca-free Mg/P inorganics and Ca/P inorganics. In vitro cytotoxicity assay revealed different behaviors of Human Umbilical Vein Endothelial Cells (HUVECs) and Human Aorta Vascular Smooth Muscle Cells (VSMCs) to material extracts. HUVECs showed increasing nitric oxide (NO) release and tolerable toxicity, whereas VSMCs exhibited limited decreasing viability with time. Platelet adhesion, hemolysis and coagulation tests of these Mg-Li-Zn alloys showed different degrees of activation behavior, in which the hemolysis of the Mg-3.5Li-2Zn alloy was lower than 5%. These results indicated the potential of the Mg-Li-Zn alloys as good candidate materials for cardiovascular stent applications. Mg-Li alloys are promising as absorbable metallic biomaterials, which however have not received significant attention since the low strength, controversial corrosion performance and the doubts in Li toxicity. The Mg-Li-Zn alloy in the present study revealed much improved mechanical properties higher than most reported binary Mg-Li and ternary Mg-Li-X alloys, with superior corrosion resistance in cell culture media. Surprisingly, the addition of Li and Zn showed increased nitric oxide release. The present study indicates good potential of Mg-Li-Zn alloy as

  4. Neutronics Evaluation of Lithium-Based Ternary Alloys in IFE Blankets

    Energy Technology Data Exchange (ETDEWEB)

    Jolodosky, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Fratoni, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-11-20

    Pre-conceptual fusion blanket designs require research and development to reflect important proposed changes in the design of essential systems, and the new challenges they impose on related fuel cycle systems. One attractive feature of using liquid lithium as the breeder and coolant is that it has very high tritium solubility and results in very low levels of tritium permeation throughout the facility infrastructure. However, lithium metal vigorously reacts with air and water and presents plant safety concerns. If the chemical reactivity of lithium could be overcome, the result would have a profound impact on fusion energy and associated safety basis. The overriding goal of this project is to develop a lithium-based alloy that maintains beneficial properties of lithium (e.g. high tritium breeding and solubility) while reducing overall flammability concerns. To minimize the number of alloy combinations that must be explored, only those alloys that meet certain nuclear performance metrics will be considered for subsequent thermodynamic study. The specific scope of this study is to evaluate the neutronics performance of lithium-based alloys in the blanket of an inertial confinement fusion (ICF) engine. The results of this study will inform the development of lithium alloys that would guarantee acceptable neutronics performance while mitigating the chemical reactivity issues of pure lithium.

  5. Magnetic transition induced by mechanical deformation in Fe{sub 60}Al{sub 40−x}Si{sub x} ternary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Legarra, E., E-mail: estibaliz.legarra@ehu.es [Dpto. Electricidad y Electronica, Universidad del Pais Vasco (UPV/EHU), CP. 644, 48080 Bilbao (Spain); Apiñaniz, E. [Dpto. Fisica Aplicada I, Universidad del Pais Vasco, Alameda de Urquijo s/n, 48013 Bilbao (Spain); Plazaola, F. [Dpto. Electricidad y Electronica, Universidad del Pais Vasco (UPV/EHU), CP. 644, 48080 Bilbao (Spain); Jimenez, J.A. [Centro Nacional de Investigaciones Metalurgicas (CENIM), Avda. Gregorio del amo 8, 28040 Madrid (Spain)

    2014-02-15

    Highlights: • Fe{sub 60}Al{sub 40−x}Si{sub x} alloys were disordered by means of planetary ball milling technique. • Paramagnetic to ferromagnetic transition is observed with disordering. • Si addition hinders the disordering process and the increase of the lattice parameter. • Si addition promotes the paramagnetic to ferromagnetic transition. -- Abstract: We have used Mössbauer spectroscopy and X-ray diffraction to study the influence of different Al/Si ratios on the structural and magnetic properties of the mechanically deformed Fe{sub 60}Al{sub 40−x}Si{sub x} alloys. The results indicate that ternary alloys also present the magnetic transition with disordering observed in binary Fe{sub 60}Al{sub 40} alloys. Besides, Si introduction has two opposite contributions. From a structural point of view, hinders the disordering process, but, from a magnetic point of view promotes the magnetic transition.

  6. Nitinol versus steel partially covered self-expandable metal stent for malignant distal biliary obstruction: a randomized trial.

    Science.gov (United States)

    Soderlund, Claes; Linder, Stefan; Bergenzaun, Per E; Grape, Tomas; Hakansson, Hans-Olof; Kilander, Anders; Lindell, Gert; Ljungman, Martin; Ohlin, Bo; Nielsen, Jorgen; Rudberg, Claes; Stotzer, Per-Ove; Svartholm, Erik; Toth, Ervin; Frozanpor, Farshad

    2014-11-01

    Covered nitinol alloy self-expandable metal stents (SEMSs) have been developed to overcome the shortcomings of steel SEMS in patients with malignant biliary obstruction. In a randomized, multicenter trial, we compared stent patency, patient survival, and adverse events in patients with partly covered stents made from steel or nitinol. A total of 400 patients with unresectable distal malignant biliary obstruction were randomized at endoscopic retrograde cholangiopancreatography (ERCP) to insertion of a steel or nitinol partially covered SEMS, with 200 patients in each group. The primary outcome was confirmed stent failure during 300 days of follow-up.  At 300 days, the proportion of patients with patent stents was 77 % in the steel group, compared with 89 % in the nitinol group (P = 0.01). Confirmed stent failure occurred more often in the steel SEMS group compared with the nitinol SEMS group, in 30 versus 14 patients (P = 0.02). Stent migration occurred in 13 patients in the steel group and in 3 patients in the nitinol group (P = 0.01). Median patient survival (secondary outcome) was 137 days and 120 days in the steel SEMS and nitinol SEMS groups, respectively (P = 0.59). The nitinol SEMS showed longer patency time, and the nitinol group had fewer patients with stent failure, compared with the steel SEMS group. We could not detect any differences between the two groups regarding survival time, and regarding adverse event rate.Clinical trial registration : NCT 00980889. © Georg Thieme Verlag KG Stuttgart · New York.

  7. Investigation of solidification behavior of the Sn-rich ternary Sn–Bi–Zn alloys

    Directory of Open Access Journals (Sweden)

    S Mladenović

    2017-03-01

    Full Text Available Solidification properties and microstructure of six as-cast Sn–Bi–Zn alloys with 80 at.% of Sn and variable contents of Bi and Zn were experimentally investigated using the scanning electron microscopy (SEM with energy-dispersive X-ray spectroscopy (EDS and differential scanning calorimetry (DSC. The experimentally obtained results were compared with predicted phase equilibria according to the calculation of phase diagram (CALPHAD method and by the Scheil solidification simulation.

  8. Precipitation kinetics in binary Fe–Cu and ternary Fe–Cu–Ni alloys via kMC method

    Directory of Open Access Journals (Sweden)

    Yi Wang

    2017-08-01

    Full Text Available The precipitation kinetics of coherent Cu rich precipitates (CRPs in binary Fe–Cu and ternary Fe–Cu–Ni alloys during thermal aging was modelled by the kinetic Monte Carlo method (kMC. A good agreement of the precipitation kinetics of Fe–Cu was found between the simulation and experimental results, as observed by means of advancement factor and cluster number density. This agreement was obtained owing to the correct description of the fast cluster mobility. The simulation results indicate that the effects of Ni are two-fold: Ni promotes the nucleation of Cu clusters; while the precipitation kinetics appears to be delayed by Ni addition during the coarsening stage. The apparent delayed precipitation kinetics is revealed to be related with the cluster mobility, which are reduced by Ni addition. The reduction effect of the cluster mobility weakens when the CRPs sizes increase. The results provide a view angle on the effects of solute elements upon Cu precipitation kinetics through the consideration of the non-conventional cluster growth mechanism, and kMC is verified to be a powerful approach on that.

  9. Atomistic modeling of ternary additions to NiTi and quaternary additions to Ni-Ti-Pd, Ni-Ti-Pt and Ni-Ti-Hf shape memory alloys

    Energy Technology Data Exchange (ETDEWEB)

    Mosca, H.O., E-mail: hmosca@cnea.gov.ar [Gcia. Investigacion y Aplicaciones, CNEA, Av. Gral Paz 1499, B1650KNA San Martin (Argentina); GCMM, UTN, FRG Pacheco, Av. H. Yrigoyen 288, Gral. Pacheco (Argentina); Bozzolo, G. [Loyola University Maryland, 4501 N. Charles St., Baltimore, MD 21210 (United States); Grosso, M.F. del [Gcia. Investigacion y Aplicaciones, CNEA, Av. Gral Paz 1499, B1650KNA San Martin (Argentina); GCMM, UTN, FRG Pacheco, Av. H. Yrigoyen 288, Gral. Pacheco (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas, CONICET (Argentina)

    2012-08-15

    The behavior of ternary and quaternary additions to NiTi shape memory alloys is investigated using a quantum approximate method for the energetics. Ternary additions X to NiTi and quaternary additions to Ni-Ti-Pd, Ni-Ti-Pt, and Ni-Ti-Hf alloys, for X=Au, Pt, Ir, Os, Re, W, Ta,Ag, Pd, Rh, Ru, Tc, Mo, Nb, Zr, Zn, Cu, Co, Fe, Mn, V, Sc, Si, Al and Mg are considered. Bulk properties such as lattice parameter, energy of formation, and bulk modulus of the B2 alloys are studied for variations due to the presence of one or two simultaneous additives.

  10. Measurement of Hydrogen Absorption in Ternary Alloys with Volumetric (Sieverts Loop) Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Aceves, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-10-26

    The Sieverts loop is an inexpensive, robust and reliable methodology for calculating hydrogen absorption in materials [1]. In this approach, we start by storing a sample of the material being tested in the volume Vcell (Figure 1) and initiate the process by producing a high vacuum in the system while the material sample is heated to eliminate (most of) the hydrogen and other impurities previously absorbed. The system typically operates isothermally, with the volume Vref at ambient temperature and the sample at a temperature of interest – high enough to liquefy the alloy for the current application to nuclear fusion.

  11. Band gap characterization of ternary BBi1-xNx (0≤x≤1) alloys using modified Becke-Johnson (mBJ) potential

    Science.gov (United States)

    Yalcin, Battal G.

    2015-04-01

    The semi-local Becke-Johnson (BJ) exchange-correlation potential and its modified form proposed by Tran and Blaha have attracted a lot of interest recently because of the surprisingly accurate band gaps they can deliver for many semiconductors and insulators (e.g., sp semiconductors, noble-gas solids, and transition-metal oxides). The structural and electronic properties of ternary alloys BBi1-xNx (0≤x≤1) in zinc-blende phase have been reported in this study. The results of the studied binary compounds (BN and BBi) and ternary alloys BBi1-xNx structures are presented by means of density functional theory. The exchange and correlation effects are taken into account by using the generalized gradient approximation (GGA) functional of Wu and Cohen (WC) which is an improved form of the most popular Perdew-Burke-Ernzerhof (PBE). For electronic properties the modified Becke-Johnson (mBJ) potential, which is more accurate than standard semi-local LDA and PBE calculations, has been chosen. Geometric optimization has been implemented before the volume optimization calculations for all the studied alloys structure. The obtained equilibrium lattice constants of the studied binary compounds are in coincidence with experimental works. And, the variation of the lattice parameter of ternary alloys BBi1-xNx almost perfectly matches with Vegard's law. The spin-orbit interaction (SOI) has been also considered for structural and electronic calculations and the results are compared to those of non-SOI calculations.

  12. EIS and XPS investigations on the corrosion mechanism of ternary Zn-Co-Mo alloy coatings in NaCl solution

    Science.gov (United States)

    Winiarski, J.; Tylus, W.; Szczygieł, B.

    2016-02-01

    The changes in composition of the corrosion products of electrodeposited ternary Zn-Co-Mo alloy coatings on AISI 1015 steel during exposure to 0.5 mol dm-3 NaCl solution were investigated. XPS studies demonstrated that at the initial stage of corrosion on the surface of Zn-Co-Mo coating zinc hydroxide layer is formed. Hydroxyl groups react with chloride and carbonate ions which lead to the formation of zinc hydroxy carbonates and zinc hydroxy chlorides. The share of these compounds in the oxidation products is initially large. However, with time zinc hydroxy compounds slowly changes to zinc oxide, which is more stable corrosion product. It was estimated that after 24 h of exposure to NaCl solution nearly 60% of zinc detected on the surface of Zn-Co-Mo coating was present in the ZnO form, 18% in the form of zinc hydroxy chloride, and more than 21% as zinc hydroxy carbonate. XPS analyses revealed that the amount of zinc hydroxy chloride increases as the exposure time lengthens and it is significantly higher than at the surface of binary Zn-Co coating. The presence of crystalline zinc chloride hydroxide as a stable product of corrosion of ternary Zn-Co-Mo alloy coating in a 0.5 mol dm-3 NaCl solution was confirmed by XRD analysis. According to XRD and FTIR other zinc corrosion products like: ZnO, Zn(OH)2 and Zn5(CO3)2(OH)6 were also present. The results of XPS and EIS measurements allow us to assume that in the presence of Mo in the alloy, on the surface of ternary Zn-Co-Mo alloy (3.4 wt.% Co, 2.7 wt.% Mo) coating more zinc hydroxy chloride is formed, which favors higher corrosion resistance of this coating.

  13. Compositional bowing of band energies and their deformation potentials in strained InGaAs ternary alloys: A first-principles study

    Energy Technology Data Exchange (ETDEWEB)

    Khomyakov, Petr A.; Luisier, Mathieu; Schenk, Andreas [Integrated Systems Laboratory, Department of Information Technology and Electrical Engineering, ETH Zurich, Gloriastrasse 35, 8092 Zurich (Switzerland)

    2015-08-10

    Using first-principles calculations, we show that the conduction and valence band energies and their deformation potentials exhibit a non-negligible compositional bowing in strained ternary semiconductor alloys such as InGaAs. The electronic structure of these compounds has been calculated within the framework of local density approximation and hybrid functional approach for large cubic supercells and special quasi-random structures, which represent two kinds of model structures for random alloys. We find that the predicted bowing effect for the band energy deformation potentials is rather insensitive to the choice of the functional and alloy structural model. The direction of bowing is determined by In cations that give a stronger contribution to the formation of the In{sub x}Ga{sub 1−x}As valence band states with x ≳ 0.5, compared to Ga cations.

  14. Phase separation in ternary system of Ni{sub 3}Mn{sub x}Al{sub 1−x} alloys

    Energy Technology Data Exchange (ETDEWEB)

    Volkova, N.V., E-mail: nvolkova@imp.uran.ru [M.N. Miheev Institute of Metal Physics, Ural Branch, Russian Academy of Sciences, ul. S. Kovalevskoi 18, Ekaterinburg 620137 (Russian Federation); Kourov, N.I. [M.N. Miheev Institute of Metal Physics, Ural Branch, Russian Academy of Sciences, ul. S. Kovalevskoi 18, Ekaterinburg 620137 (Russian Federation); Marchenkov, V.V. [M.N. Miheev Institute of Metal Physics, Ural Branch, Russian Academy of Sciences, ul. S. Kovalevskoi 18, Ekaterinburg 620137 (Russian Federation); Ural Federal University, 620002 Ekaterinburg (Russian Federation)

    2016-03-01

    The concentration dependence of the resistance of the alloys of Ni{sub 3}Mn{sub x}Al{sub 1−x} system is described in the framework of the percolation theory in the model of an effective medium. The regions corresponding to the alloys of terminal compositions are present in the entire volume of the samples. The formation of an infinite cluster occurs near the percolation threshold x=0.3 for the phase of the Ni{sub 3}Al and x=0.7 for the phase of the Ni{sub 3}Mn type. This makes it possible to suppose that in the ternary Ni{sub 3}Mn{sub x}Al{sub 1−x} alloys in the intermediate region of concentrations there is realized an inhomogeneous heterophase structure.

  15. Structural and optoelectronic properties of BxAl1-xSb ternary alloys: first principles calculations

    Science.gov (United States)

    Benchehima, Miloud; Abid, Hamza; Chaouche, Abdallah Chabane; Resfa, Abbes

    2017-03-01

    In this paper, the full potential linearized augmented plane wave (FP-LAPW) formalism based on density functional theory (DFT) has been performed. To study the structural properties of BxAl1-xSb at different boron concentrations x (0 ≤ x ≤ 1), we have used the local density approximation (LDA) and the generalized gradient approximation of Wu and Cohen (GGA-WC). The phase stability of AlSb and BSb binary compounds in zinc-blend and rock salt phases has been investigated. The equilibrium lattice constant (a), bulk modulus (B) and pressure derivative of bulk modulus B' have been evaluated in both phases. We observe a small deviation from the linear concentration dependence (LCD) of the lattice constant parameter, while an important deviation of bulk modulus from "LCD" has been remarked. We have compared the results obtained to the available theoretical and experimental data for the binaries. The optoelectronic properties of BxAl1-xSb are studied in the most stable determined phase. In addition to the "GGA-WC", the GGA of Engel and Vosko, and the recent developed Tran-Blaha-modified Becke-Johnson (TB-mBJ) schemes were used to study the electronic properties of BxAl1-xSb ternary alloys. It is found that the band gap of BxAl1-xSb vary non-linearly with the boron concentrations, giving a negative deviation from Vegard's law. In addition, the optical properties such as the dielectric function, complex refractive index, absorption coefficient, optical conductivity and absorption coefficient are discussed in detail.

  16. Study on Mg/Al Weld Seam Based on Zn–Mg–Al Ternary Alloy

    Directory of Open Access Journals (Sweden)

    Liming Liu

    2014-02-01

    Full Text Available Based on the idea of alloying welding seams, a series of Zn–xAl filler metals was calculated and designed for joining Mg/Al dissimilar metals by gas tungsten arc (GTA welding. An infrared thermography system was used to measure the temperature of the welding pool during the welding process to investigate the solidification process. It was found that the mechanical properties of the welded joints were improved with the increasing of the Al content in the Zn–xAl filler metals, and when Zn–30Al was used as the filler metal, the ultimate tensile strength could reach a maximum of 120 MPa. The reason for the average tensile strength of the joint increasing was that the weak zone of the joint using Zn–30Al filler metal was generated primarily by α-Al instead of MgZn2. When Zn–40Al was used as the filler metal, a new transition zone, about 20 μm-wide, appeared in the edge of the fusion zone near the Mg base metal. Due to the transition zones consisting of MgZn2- and Al-based solid solution, the mechanical property of the joints was deteriorated.

  17. Macrosegregation in horizontal direct chill casting of ternary Al alloys: Investigation of solid motion

    Science.gov (United States)

    Vušanović, I.; Krane, M. J. M.

    2012-01-01

    Macrosegregation in direct chill casting processes is controlled by fluid flow due to the thermosolutal natural and forced convection, shrinkage, and transport of unattached solid grains. Because grain refinement is usually used in aluminum direct chill casting, some effort must be made to model free-floating solid grains, and their attachment to a rigid mushy zone. Criteria for attachment vary, but many are based on using a critical solid packing fraction, which is treated as uniform and constant throughout the domain. In the case of horizontal casting (HDC), gravity acts perpendicularly to the casting direction, and the assumption of a uniform packing fraction cannot be applied because the solid particles attach to some surfaces by settling and others by being swept into the rigid solid from below. In this simulation of HDC casting of an Al-Cu-Mg alloy, the rigid and unattached solid is tracked separately, and a rule set is developed to determine the attachment of free-floating solid. Comparison between cases with and without unattached solid movement shows qualitatively different results, particularly in bottom part of slab. Non-uniform packing fractions cause very different segregation patterns in the lower half of the ingot compared to the cases with no solid movement, less segregation near centerline compared to uniform packing fraction cases, and positive segregation near the place where inlet jet impinges on the mushy zone.

  18. 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.

  19. Device Fabrication using Crystalline CdTe and CdTe Ternary Alloys Grown by MBE

    Energy Technology Data Exchange (ETDEWEB)

    Zaunbrecher, Katherine; Burst, James; Seyedmohammadi, Shahram; Malik, Roger; Li, Jian V.; Gessert, Timothy A.; Barnes, Teresa

    2015-06-14

    We fabricated epitaxial CdTe:In/CdTe:As homojunction and CdZnTe/CdTe and CdMgTe/CdTe heterojunction devices grown on bulk CdTe substrates in order to study the fundamental device physics of CdTe solar cells. Selection of emitter-layer alloys was based on passivation studies using double heterostructures as well as band alignment. Initial results show significant device integration challenges, including low dopant activation, high resistivity substrates and the development of low-resistance contacts. To date, the highest open-circuit voltage is 715 mV in a CdZnTe/CdTe heterojunction following anneal, while the highest fill factor of 52% was attained in an annealed CdTe homojunction. In general, all currentvoltage measurements show high series resistance, capacitancevoltages measurements show variable doping, and quantum efficiency measurements show low collection. Ongoing work includes overcoming the high resistance in these devices and addressing other possible device limitations such as non-optimum junction depth, interface recombination, and reduced bulk lifetime due to structural defects.

  20. Magnetic properties of the ternary alloy system (FexNi1-x)11Se8 for 0.042

    Science.gov (United States)

    Sharma, Y. K.

    1990-07-01

    The ternary alloy system (FexNi1-x)11Se8 for 0.042

  1. Pit initiation on nitinol in simulated physiological solutions.

    Science.gov (United States)

    Pound, Bruce G

    2017-08-21

    Inclusions appear to play a crucial role in the initiation of pitting on nitinol, but the reason remains unclear. Furthermore, it has not been established whether the type of inclusion is a central factor. In this study, potentiodynamic polarization together with scanning electron microscopy and energy dispersive X-ray spectroscopy were used to provide more insight into the initiation of pits on electropolished nitinol wire. Corrosion was limited to a single primary pit on each of the few wire samples that exhibited breakdown. The pit contained numerous Ti2 NiOx inclusions, but secondary pits that developed within the primary pit provided evidence that these inclusions were the sites of pit initiation. Although several theories have been proposed to account for pit initiation at inclusions in mechanically polished and electropolished nitinol, titanium depletion in the adjacent alloy matrix appears to provide the most viable explanation. The key factor appears to be the size of the inclusion and therefore the extent of titanium depletion in the alloy matrix. The type of inclusion evidently plays a secondary role at most. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2017. © 2017 Wiley Periodicals, Inc.

  2. Ab-initio study of structural, elastic, electronic and thermodynamic properties of BaxSr1−xS ternary alloys

    Directory of Open Access Journals (Sweden)

    Chelli S.

    2015-12-01

    Full Text Available The structural, elastic, electronic and thermodynamic properties of BaxSr1−xS ternary alloys have been investigated using the full-potential (linearized augmented plane wave method. The ground state properties, such as lattice constant, bulk modulus and elastic constants, are in good agreement with numerous experimental and theoretical data. The dependence of the lattice parameters, bulk modulus and band gap on the composition x was analyzed. Deviation of the lattice constant from Vegard’s law and the bulk modulus from linear concentration dependence (LCD was observed. The microscopic origins of the gap bowing were explained by using the approach of Zunger et al. The thermodynamic stability of BaxSr1−xS alloy was investigated by calculating the excess enthalpy of mixing, ΔHm and the calculated phase diagram showed a broad miscibility gap with a critical temperature.

  3. Influence of ternary elements (X = Si, B, Cr) on TiAlN coating deposited by magnetron sputtering process with single alloying targets

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Duck Hyeong [Korea Institute of Industrial Technology, Heat and Surface Technology Service Center, Incheon, 426-791 (Korea, Republic of); Department of Materials Engineering, Hanyang University, Gyeonggi-do, 426-791 (Korea, Republic of); Moon, Kyoung Il; Shin, Seung Yong [Korea Institute of Industrial Technology, Heat and Surface Technology Service Center, Incheon, 426-791 (Korea, Republic of); Lee, Caroline Sunyong, E-mail: sunyonglee@hanyang.ac.kr [Department of Materials Engineering, Hanyang University, Gyeonggi-do, 426-791 (Korea, Republic of)

    2013-11-01

    Ti–Al based single alloying targets were prepared by mechanical alloying and spark plasma sintering. Also, Si, B, and Cr added targets were prepared to improve wear and corrosion properties. The investigation on the alloying targets showed that their microstructures were about 20–30 nm in size and all the elements were homogeneously distributed. Ternary Ti–Al-based coatings were deposited by magnetron sputtering method with various alloying targets, such as TiAlSi, TiAlB and TiAlCr. The composition of the coating was almost the same with that of the target. Their microstructures and mechanical properties were investigated by X-ray diffractometer, field emission scanning electron microscope, nano-indenter, tribometer and etc. Moreover, effects of 3rd element on the wear and corrosion properties of Ti–Al–N based coatings were studied here. From the results of TiAlN-X coating properties, the sample coated with TiAlN-B showed the highest hardness. Moreover, TiAlN-Cr coatings showed the best friction coefficient in oil condition and best corrosion resistance with the lowest corrosion current density. Therefore, easy method of coating TiAlN with ternary element using single target, was demonstrated as well as its improved structural properties. - Highlights: • Improve properties of TiAlN coatings by adding third elements such as Si, B, and Cr • TiAlN-B coatings showed the highest hardness. • TiAlN-Cr coatings showed the best friction coefficient in oil condition. • TiAlN-Cr coatings showed the best corrosion resistance.

  4. A Platinum Monolayer Core-Shell Catalyst with a Ternary Alloy Nanoparticle Core and Enhanced Stability for the Oxygen Reduction Reaction

    Directory of Open Access Journals (Sweden)

    Haoxiong Nan

    2015-01-01

    Full Text Available We synthesize a platinum monolayer core-shell catalyst with a ternary alloy nanoparticle core of Pd, Ir, and Ni. A Pt monolayer is deposited on carbon-supported PdIrNi nanoparticles using an underpotential deposition method, in which a copper monolayer is applied to the ternary nanoparticles; this is followed by the galvanic displacement of Cu with Pt to generate a Pt monolayer on the surface of the core. The core-shell Pd1Ir1Ni2@Pt/C catalyst exhibits excellent oxygen reduction reaction activity, yielding a mass activity significantly higher than that of Pt monolayer catalysts containing PdIr or PdNi nanoparticles as cores and four times higher than that of a commercial Pt/C electrocatalyst. In 0.1 M HClO4, the half-wave potential reaches 0.91 V, about 30 mV higher than that of Pt/C. We verify the structure and composition of the carbon-supported PdIrNi nanoparticles using X-ray powder diffraction, X-ray photoelectron spectroscopy, thermogravimetry, transmission electron microscopy, and energy dispersive X-ray spectrometry, and we perform a stability test that confirms the excellent stability of our core-shell catalyst. We suggest that the porous structure resulting from the dissolution of Ni in the alloy nanoparticles may be the main reason for the catalyst’s enhanced performance.

  5. Effects of varying indium composition on the thermoelectric properties of In{sub x}Ga{sub 1-x}Sb ternary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Nirmal Kumar, V.; Hayakawa, Y. [Shizuoka University, Graduate School of Science and Technology, Hamamatsu (Japan); Shizuoka University, Research Institute of Electronics, Hamamatsu, Shizuoka (Japan); Arivanandan, M. [Anna University, Centre for Nanoscience and Technology, Chennai (India); Koyoma, T. [Shizuoka University, Research Institute of Electronics, Hamamatsu, Shizuoka (Japan); Udono, H. [Ibaraki University, Faculty of Engineering, Hitachi (Japan); Inatomi, Y. [Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, Sagamihara (Japan); SOKENDAI (The Graduate University for Advanced Studies), School of Physical Sciences, Sagamihara (Japan)

    2016-10-15

    In{sub x}Ga{sub 1-x}Sb (x = 0-1), a III-V ternary alloy, was grown by melt solidification process. The effects of varying indium composition on the thermoelectric properties of In{sub x}Ga{sub 1-x}Sb polycrystals were studied for the first time. The segregations of indium and gallium elements were observed in the grown crystals, and the defects present in crystals were revealed by etching process. Room-temperature Raman measurement revealed that the dominant optical modes of phonon vibrations in InSb and GaSb binaries were suppressed in In{sub x}Ga{sub 1-x}Sb ternaries. The in-phase vibrations of acoustic mode phonons were scattered more effectively in In{sub x}Ga{sub 1-x}Sb by the present defects, and the relative value of lattice thermal conductivity was reduced. Thus, the thermal conductivity of InSb and GaSb binaries was drastically reduced in In{sub x}Ga{sub 1-x}Sb by alloy scattering. InSb indicated the highest ZT 0.51 because of its higher power factor 70 μW/cm K{sup 2}. Next to InSb, In{sub 0.8}Ga{sub 0.2}Sb had higher ZT value of 0.29 at 600 K among the In{sub x}Ga{sub 1-x}Sb ternaries. The ZT of In{sub 0.8}Ga{sub 0.2}Sb was increased about 30 times than that of GaSb by the increase of power factor as well as the decrease of thermal conductivity. (orig.)

  6. First-principles study on half-metallic ferromagnetic properties of Zn{sub 1-x}V{sub x}Se ternary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Khatta, Swati; Tripathi, S.K.; Prakash, Satya [Panjab University, Central of Advanced Study in Physics, Department of Physics, Chandigarh (India)

    2017-09-15

    The spin-polarised density functional theory along with self-consistent plane-wave pseudopotential is used to investigate the half-metallic ferromagnetic properties of ternary alloys Zn{sub 1-x}V{sub x}Se. The generalized gradient approximation is used for exchange-correlation potential. The equilibrium lattice constants, bulk modulus, and its derivatives are calculated. The calculated spin-polarised energy-band structures reveal that these alloys are half-metallic for x = 0.375 and 0.50 and nearly half-metallic for other values of x. The estimated direct and indirect bandgaps may be useful for the magneto-optical absorption experiments. It is found that there is strong Zn 4s, Se 4p, and V 3d orbital hybridization in the conduction bands of both the spins, while Se 4p and V 3d orbital hybridization predominates in the valence bands of both the spins. The s, p-d, and p-d orbital hybridization reduces the local magnetic moment of V atoms and small local magnetic moments are produced on Zn and Se atoms which get coupled with V atoms in ferromagnetic and antiferromagnetic phases, respectively. The conduction and valence-band-edge splittings and exchange constants predict the ferromagnetism in these alloys. The conduction band-impurity (s and p-d) exchange interaction is more significant for ferromagnetism in these alloys than the valence band-impurity (p-d) exchange interaction. (orig.)

  7. Experimental investigations and phase-field simulations of triple-phase-separation kinetics within liquid ternary Co-Cu-Pb immiscible alloys.

    Science.gov (United States)

    Wu, Y H; Wang, W L; Yan, N; Wei, B

    2017-05-01

    The phase-separation kinetics and microstructure evolution mechanisms of liquid ternary Co_{43}Cu_{40}Pb_{17} immiscible alloys are investigated by both the drop tube technique and phase-field method. Two successive phase separations take place during droplet falling and lead to the formation of a three-phase three-layer core-shell structure composed of a Co-rich core, a Cu-rich middle layer, and a Pb-rich shell. The Pb-rich shell becomes more and more conspicuous as droplet diameter decreases. Meanwhile, the Co-rich core center gradually moves away from the core-shell center. Theoretical analyses show that a larger temperature gradient inside a smaller alloy droplet induces the accelerated growth of the surface segregation shell during triple-phase separation. The residual Stokes motion and the asymmetric Marangoni convection result in the appearance of an eccentric Co-rich core and the core deviation degree is closely related to the droplet size and initial velocity. A three-dimensional phase-field model of ternary immiscible alloys, which considers the successive phase separations under the combined effects of Marangoni convection and surface segregation, is proposed to explore the formation mechanisms of three-phase core-shell structures. The simulated core-shell morphologies are consistent with the experimental observations, which verifies the model's validity in reproducing the core-shell dynamic evolution. Numerical results reveal that the development of three-phase three-layer core-shell structures can be attributed to the primary and then secondary phase separations dominated simultaneously by Marangoni convection and surface segregation. Furthermore, the effects of droplet temperature gradient on the growth kinetics of the surface segregation shell are analyzed in the light of phase-field theory.

  8. Experimental investigations and phase-field simulations of triple-phase-separation kinetics within liquid ternary Co-Cu-Pb immiscible alloys

    Science.gov (United States)

    Wu, Y. H.; Wang, W. L.; Yan, N.; Wei, B.

    2017-05-01

    The phase-separation kinetics and microstructure evolution mechanisms of liquid ternary C o43C u40P b17 immiscible alloys are investigated by both the drop tube technique and phase-field method. Two successive phase separations take place during droplet falling and lead to the formation of a three-phase three-layer core-shell structure composed of a Co-rich core, a Cu-rich middle layer, and a Pb-rich shell. The Pb-rich shell becomes more and more conspicuous as droplet diameter decreases. Meanwhile, the Co-rich core center gradually moves away from the core-shell center. Theoretical analyses show that a larger temperature gradient inside a smaller alloy droplet induces the accelerated growth of the surface segregation shell during triple-phase separation. The residual Stokes motion and the asymmetric Marangoni convection result in the appearance of an eccentric Co-rich core and the core deviation degree is closely related to the droplet size and initial velocity. A three-dimensional phase-field model of ternary immiscible alloys, which considers the successive phase separations under the combined effects of Marangoni convection and surface segregation, is proposed to explore the formation mechanisms of three-phase core-shell structures. The simulated core-shell morphologies are consistent with the experimental observations, which verifies the model's validity in reproducing the core-shell dynamic evolution. Numerical results reveal that the development of three-phase three-layer core-shell structures can be attributed to the primary and then secondary phase separations dominated simultaneously by Marangoni convection and surface segregation. Furthermore, the effects of droplet temperature gradient on the growth kinetics of the surface segregation shell are analyzed in the light of phase-field theory.

  9. Investigation of strain effects on phase diagrams in the ternary nitride alloys (InAlN, AlGaN, InGaN)

    Energy Technology Data Exchange (ETDEWEB)

    Mohamad, Ranim; Chen, Jun; Ruterana, Pierre [CIMAP, UMR 6252, CNRS-ENSICAEN-CEA-UNICAEN, Caen (France); Bere, Antoine [Laboratoire de Physique et de Chimie de l' Environnement, Universite Ouaga I Pr Joseph KI-ZERBO, Ouagadougou (Burkina Faso)

    2017-09-15

    In this work, we used a modified Stillinger-Weber potential and a methodology of free energy calculation based on numerical computation of the configuration partition function of an alloy, to make a comprehensive study of the properties of group-III nitride ternary compounds (In{sub x}Ga{sub 1-x}N; In{sub x}Al{sub 1-x}N; Al{sub x}Ga{sub 1-x}N). The wurtzite structure was used; and the critical temperatures for the random ternary alloys are determined as 2717 K for In{sub x}Al{sub 1-x}N, 1718 K for In{sub x}Ga{sub 1-x}N, and 177 K for Al{sub x}Ga{sub 1-x}N, respectively. Therefore, Al{sub x}Ga{sub 1-x}N has no unstable mixing region at typical growth temperatures around 1100 C. In contrast, In{sub x}Al{sub 1-x}N and In{sub x}Ga{sub 1-x}N exhibit a wide unstable region, which means that being thick layers, their stability as homogeneous alloys is probably limited. In agreement with other reports, it is also pointed out that the critical temperature T{sub c} may be decreased when the layers are grown under strain. Although the compression and extension have the same effect below 1.5% strain, it is shown, for the first time, that when the compressive strain goes beyond, T{sub c} abruptly increases in contrast to the case of tensile strain where it continues to decrease. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-12-01

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

  11. VANADIUM ALLOYS

    Science.gov (United States)

    Smith, K.F.; Van Thyne, R.J.

    1959-05-12

    This patent deals with vanadium based ternary alloys useful as fuel element jackets. According to the invention the ternary vanadium alloys, prepared in an arc furnace, contain from 2.5 to 15% by weight titanium and from 0.5 to 10% by weight niobium. Characteristics of these alloys are good thermal conductivity, low neutron capture cross section, good corrosion resistance, good welding and fabricating properties, low expansion coefficient, and high strength.

  12. Electronic and optical properties of ternary alloys ZnxCd1−xS, ZnxCd1−xSe, ZnSxSe1−x, MgxZn1−xSe

    Directory of Open Access Journals (Sweden)

    Benchikh K.

    2017-02-01

    Full Text Available The empirical pseudopotential method (EPM within the virtual crystal approximation (VCA is used to calculate the electronic and optical properties of ternary alloys ZnxCd1−xS, ZnxCd1−xSe, ZnSxSe1−x and MgxZn1−xSe. The alloy band structures and energy gaps are calculated using VCA which incorporates the compositional disorder as an effective potential. The calculated band structures for the ZnxCd1−xS, ZnxCd1−xSe and ZnSxSe1−x alloys show a direct band gap in the whole range of the concentration except for the MgxZn1−xSe alloy which presents a crossover from the direct gap to the indirect one.Also the dependence of the refractive index on the concentration is calculated for each ternary alloy. This parameter is found to depend nonlinearly on the alloy concentration. A detailed comparison of our results with experimental data and works of other authors has led to a good agreement.

  13. Trace element control in binary Ni-25Cr and ternary Ni-30Co-30Cr master alloy castings

    Energy Technology Data Exchange (ETDEWEB)

    Detrois, Martin [National Energy Technology Lab. (NETL), Albany, OR (United States); Oak Ridge Inst. for Science and Education (ORISE), Oak Ridge, TN (United States); Jablonski, Paul D. [National Energy Technology Lab. (NETL), Albany, OR (United States);

    2017-10-23

    Electro-slag remelting (ESR) is used for control of unwanted elements in commercial alloys. This study focuses on master alloys of Ni-25Cr and Ni-30Co-30Cr, processed through a combination of vacuum induction melting (VIM) and electro-slag remelting (ESR). Minor additions were made to control tramp element levels and modify the melting characteristics. Nitrogen and sulfur levels below 10 ppm and oxygen levels below 100 ppm were obtained in the final products. The role of the alloy additions in lowering the tramp element content, the resulting residual inclusions and the melting characteristics were determined computationally and confirmed experimentally. Additions of titanium were beneficial to the control of oxygen levels during VIM and nitrogen levels during ESR. Aluminum additions helped to control oxygen levels during remelting, however, aluminum pickup occurred when excess titanium was present during ESR. The usefulness of these master alloys for use as experimental remelt stock will also be discussed.

  14. Mechanical and Functional Properties of Laser-Welded Ti-55.8 Wt Pct Ni Nitinol Wires

    Science.gov (United States)

    Tam, B.; Khan, M. I.; Zhou, Y.

    2011-08-01

    As interest increases in incorporating Nitinol alloys in different microapplications and devices, the development of effective procedures for laser microwelding (LMW) these alloys becomes necessary. Laser welding processes applied to Nitinol have been shown to lower strength, induce inclusions of intermetallic compounds (IMCs), and alter the pseudoelastic and shape memory effects. Inconsistency in reported weld properties has also suggested that further studies are required. The current study details the mechanical, microstructural, and phase transformation properties of Nd:YAG LMW crossed Ti-55.8 wt pct Ni Nitinol wires. The effects of surface oxide on joint performance were also investigated. Fracture strength, weld microstructure, and phase transformation temperatures at varying peak power inputs were studied and compared to the unaffected base metal. Results showed good retention of strength and pseudoelastic properties, while the fusion zone exhibited higher phase transformation temperatures, which altered the active functional properties at room temperature.

  15. Shape memory alloy seals for geothermal applications. Final report. Report ESG-82-14

    Energy Technology Data Exchange (ETDEWEB)

    Friske, Warren H.; Schwartzbart, Harry

    1982-07-30

    A novel temperature-actuated seal for geothermal applications is under development. This program uses the shape memory property of nickel-titanium (Nitinol) alloys to achieve an improved seal in geothermal downhole pumps. Nitinol flange face seals and pump shaft seals have been designed, fabricated, and tested. It has been demonstrated that the shape memory effect of Nitinol alloys can be utilized to activate and maintain a leaktight seal in geothermal environments.

  16. Ternary fission

    Indian Academy of Sciences (India)

    2015-08-05

    Aug 5, 2015 ... We present the ternary fission of 252Cf and 236U within a three-cluster model as well as in a level density approach. The competition between collinear and equatorial geometry is studied by calculating the ternary fragmentation potential as a function of the angle between the lines joining the stationary ...

  17. Ternary fission

    Indian Academy of Sciences (India)

    Recently, we have studied the various aspects associated with the ternary fission process. A model, called the three-cluster model (TCM) [1–6] has been put forth. This accounts for the energy minimization of all possible ternary breakups of a heavy radioactive nucleus. Further, within the TCM we have analysed the ...

  18. Additively Manufactured and Surface Biofunctionalized Porous Nitinol

    NARCIS (Netherlands)

    Gorgin Karaji, Z; Speirs, M; Dadbakhsh, S; Kruth, J-P; Weinans, H|info:eu-repo/dai/nl/087198622; Zadpoor, A A; Amin Yavari, S|info:eu-repo/dai/nl/364172320

    2017-01-01

    Enhanced bone tissue regeneration and improved osseointegration are among the most important goals in design of multifunctional orthopedic biomaterials. In this study, we used additive manufacturing (selective laser melting) to develop multifunctional porous nitinol that combines superelasticity

  19. Alloying effect on bright-dark exciton states in ternary monolayer Mo x W1-x Se2

    Science.gov (United States)

    Liu, Yanping; Tom, Kyle; Zhang, Xiaowei; Lou, Shuai; Liu, Yin; Yao, Jie

    2017-07-01

    Binary transition metal dichalcogenides (TMDCs) in the class MX2 (M = Mo, W; X = S, Se) have been widely investigated for potential applications in optoelectronics and nanoelectronics. Recently, alloy-based monolayers of TMDCs have provided a stable and versatile technique to tune the physical properties and optimize them for potential applications. Here, we present experimental evidence for the existence of an intermediate alloy state between the MoSe2-like and the WSe2-like behavior of the neutral exciton (X 0) using temperature-dependent photoluminescence (PL) of the monolayer Mo x W1-x Se2 alloy. The existence of a maximum PL intensity around 120 K can be explained by the competition between the thermally activated bright states and the non-radiative quenching of the bright states. Moreover, we also measured localized exciton (XB ) PL peak in the alloy and the observed behavior agrees well with a model previously proposed for the 3D case, which indicates the theory also applies to 2D systems. Our results not only shed light on bright-dark states and localized exciton physics of 2D semiconductors, but also offer a new route toward the control of the bright-dark transition and tailoring optical properties of 2D semiconductors through defect engineering.

  20. Influence of aging at 180C on the corrosion behaviour of a ternary Al-Li-Zr alloy

    DEFF Research Database (Denmark)

    Ambat, Rajan; Prasad, R.K.; Dwarakadasa, E.S.

    1994-01-01

    The influence of aging at 180 °C on the corrosion behaviour of an Al-1.5%Li-0.1%Zr alloy has been studied using weight loss, open circuit potential (OCP) measurements and potentiodynamic polarization measurements in 3.5% NaCl solution. Corrosion rates obtained from weight loss and Icorr values...

  1. Stress Corrosion Evaluation of Nitinol 60 for the International Space Station Water Recycling System

    Science.gov (United States)

    Torres, P. D.

    2016-01-01

    A stress corrosion cracking (SCC) evaluation of Nitinol 60 was performed because this alloy is considered a candidate bearing material for the Environmental Control and Life Support System (ECLSS), specifically in the Urine Processing Assembly of the International Space Station. An SCC evaluation that preceded this one during the 2013-2014 timeframe included various alloys: Inconel 625, Hastelloy C-276, titanium (Ti) commercially pure (CP), Ti 6Al-4V, extra-low interstitial (ELI) Ti 6Al-4V, and Cronidur 30. In that evaluation, most specimens were exposed for a year. The results of that evaluation were published in NASA/TM-2015-218206, entitled "Stress Corrosion Evaluation of Various Metallic Materials for the International Space Station Water Recycling System,"1 available at the NASA Scientific and Technical Information program web page: http://www.sti.nasa.gov. Nitinol 60 was added to the test program in 2014.

  2. Corrosion Resistance of Electroless Ni-Cu-P Ternary Alloy Coatings in Acidic and Neutral Corrosive Mediums

    OpenAIRE

    Mbouillé Cissé; Mohamed Abouchane; Tayeb Anik; Karima Himm; Rida Allah Belakhmima; Mohamed Ebn Touhami; Rachid Touir; Abderrahmane Amiar

    2010-01-01

    Electroless Ni-Cu-P alloy coatings were deposited on the ordinary steel substrate in an acidic hypophosphite-type plating bath. These coatings were characterized by a scanning electron microscope (SEM) and an X-ray diffraction. The micrograph shows that coating presents a nodular aspect and is relatively homogeneous and very smooth. The EDX analysis shows that the coating contains 12 wt.% of phosphorus element with a predominance of nickel element. In addition, the anticorrosion properties of...

  3. Solutal configuration during coupled two-phase [α (Al) + θ-Al2Cu] planar univariant eutetic growth in Al-Cu-(Ag, Si) ternary eutetic alloys

    Science.gov (United States)

    De Wilde, J.; Froyen, L.

    2005-03-01

    The solutal configuration, both in the solid as in the liquid, during coupled two-phase planar growth as it can be obtained during unidirectional solidification of ternary Al-Cu-Ag and Al-Cu-Si alloys with a composition close to the univariant eutectic reaction L → α (Al) + θ-Al2Cu has been investigated during preparatory ground experiments. During solidification, both Al and Cu can be redistributed in the liquid by cross-diffusion parallel to the planar solid/liquid interface. However the third element, i.e. Ag and Si, must be segregated over a much longer distance. In the case of Ag, a diffusive stable solute boundary layer has been observed. Si however is found to be solutal unstable and gravity driven solutal convection breaks up the boundary layer. In both cases, however, the interface is prone to a Mullins-Sekerka instability giving rise to two-phase cellular growth at a critical value of the growth velocity. In the solid, the α(Al) composition, determined by the solidus line, changes with changing growth velocity.

  4. The phase diagrams of the mixed-spin ternary-alloy consisting of half-integer spins: Standard-random approach

    Science.gov (United States)

    Albayrak, Erhan

    2018-02-01

    The ternary-alloy in the form ABpC1-p is investigated on the Bethe lattice with the odd numbered shells containing only A atoms (spin-1/2), while the even shells randomly containing either B (spin-3/2) or C (spin-5/2) atoms with different concentrations p and 1 - p, respectively. The phase diagrams are calculated on the (p ,kTc /JAB) and (R = |JAC | /JAB ,kTc /JAB) planes for given values of R and p, respectively, with the coordination numbers z = 3 , 4 , 5 and 6 by studying the thermal variations of the order-parameters. It is found that there exist a critical value of R, i.e. Rc ≅ 0.653, which is independent of z. In addition, the critical temperatures increase as z increases. The present work is an extension of the previous work [1] and it only differs from it by the implementation technique of randomness into the model. The obtained phase diagrams are in agreement with the site-dependent random case [1] except at low temperatures. On the other hand, there is an overall agreement with the literature.

  5. First-principle study of the structural, electronic, and optical properties of cubic InN{sub x}P{sub 1-x} ternary alloys under hydrostatic pressure

    Energy Technology Data Exchange (ETDEWEB)

    Hattabi, I. [Ibn Khaldoun Univ. de Tiaret (Algeria). Lab. Synthese et Catalyse; Abdiche, A.; Riane, R. [Sidi-bel-Abbes Univ. (Algeria). Applied Materials Lab.; Moussa, R. [Sidi-bel-Abbes Univ. (Algeria). Physic Dept.; Hadji, K. [Ibn Khaldoun Univ. de Tiaret (Algeria). Science and Technology Dept.; Soyalp, F. [Yuezuencue Yil Univ., Van (Turkey). Dept. of Physics; Varshney, Dinesh [Devi Ahilya Univ., Indore (India). Materials Science Lab.; Syrotyuk, S.V. [National Univ. ' Lviv Polytechnic' , Lviv (Ukraine). Semiconductor Electronics Dept.; Khenata, R. [Mascara Univ. (Algeria). Lab. de Physique Quantique et de Modelisation Mathematique (LPQ3M)

    2016-07-01

    In this article, we present results of the first-principle study of the structural, electronic, and optical properties of the InN, InP binary compounds and their related ternary alloy InN{sub x}P{sub 1-x} in the zinc-blend (ZB) phase within a nonrelativistic full potential linearised augmented plan wave (FP-LAPW) method using Wien2k code based on the density functional theory (DFT). Different approximations of exchange-correlation energy were used for the calculation of the lattice constant, bulk modulus, and first-order pressure derivative of the bulk modulus. Whereas the lattice constant decreases with increasing nitride composition x. Our results present a good agreement with theoretical and experimental data. The electronic band structures calculated using Tran-Blaha-modified Becke-Johnson (TB-mBJ) approach present a direct band gap semiconductor character for InN{sub x}P{sub 1-x} compounds at different x values. The electronic properties were also calculated under hydrostatic pressure for (P=0.00, 5.00, 10.0, 15.0, 20.0, 25.0 GPa) where it is found that the InP compound change from direct to indirect band gap at the pressure P≥7.80 GPa. Furthermore, the pressure effect on the dielectric function and the refractive index was carried out. Results obtained in our calculations present a good agreement with available theoretical reports and experimental data.

  6. Extended x-ray absorption fine structure and micro-Raman spectra of Bridgman grown Cd1-xZnxTe ternary alloys

    Science.gov (United States)

    Talwar, Devki N.; Feng, Zhe Chuan; Lee, Jyh-Fu; Becla, P.

    2014-03-01

    We have performed low-temperature micro-Raman scattering and extended x-ray absorption fine-structure (EXAFS) measurements on the Bridgman-grown bulk zinc-blende Cd1-x Zn x Te (1.0 ≧̸ x ≧̸ 0.03) ternary alloys to comprehend their structural and lattice dynamical properties. The micro-Raman results are carefully appraised to authenticate the classical two-phonon mode behavior insinuated by far-infrared (FIR) reflectivity study. The composition-dependent EXAFS experiments have revealed a bimodal distribution of the nearest-neighbor bond lengths—its analysis by first-principles bond-orbital model enabled us to estimate the lattice relaxations around Zn/Cd atoms in CdTe/ZnTe to help evaluate the necessary force constant variations for constructing the impurity-perturbation matrices. The simulated results of impurity vibrational modes by average-t-matrix Green’s function (ATM-GF) theory has put our experimental findings of the gap mode ˜153 cm-1 near x ≈ 1 on a much firmer ground.

  7. The effect of Pd on the isothermal relaxation of short-range order in Au(Ag)-based ternary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ziya, A.B. [Institute of Materials Science, University of Tsukuba, Tsukuba 305-8573 (Japan) and Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan)]. E-mail: dr.a.b.ziya@bzumail.edu.pk; Ohshima, K. [Institute of Materials Science, University of Tsukuba, Tsukuba 305-8573 (Japan)

    2005-08-01

    The effect of Pd on the isothermal relaxation of short-range order (SRO) was studied in Au{sub x}Ag{sub x}Pd{sub 100-2x} (x=25, 40at%) alloys, using the residual resistometry at 77K. The short-range ordering resulted in an increase of electrical resistivity. The equilibrium values of this property characterizing the SRO-equilibrium states exhibit a linear dependence on the reciprocal of temperature. The analysis of the resistivity data using the fundamental laws of SRO-kinetics shows that the resistivity behavior can be satisfactorily explained by the two-exponentials law and leads to the determination of characteristic time constants and the activation enthalpies for the two processes. Further, it is found that both the equilibrium and kinetic behavior of these alloys are highly dependent on the concentration of Pd. The presence of Pd reduces the atomic mobility which results from a decrease in the vacancy mobility linked to the positive size effect of Pd in these alloys.

  8. Characterization of Ternary NiTiPd High-Temperature Shape-Memory Alloys under Load-Biased Thermal Cycling

    Science.gov (United States)

    Bigelow, Glen S.; Padula, Santo A.; Noebe, Ronald D.; Garg, Anita; Gaydosh, Darrell

    2010-01-01

    While NiTiPd alloys have been extensively studied for proposed use in high-temperature shape-memory applications, little is known about the shape-memory response of these materials under stress. Consequently, the isobaric thermal cyclic responses of five (Ni,Pd)49.5Ti50.5 alloys with constant stoichiometry and Pd contents ranging from 15 to 46 at. pct were investigated. From these tests, transformation temperatures, transformation strain (which is proportional to work output), and unrecovered strain per cycle (a measure of dimensional instability) were determined as a function of stress for each alloy. It was found that increasing the Pd content over this range resulted in a linear increase in transformation temperature, as expected. At a given stress level, work output decreased while the amount of unrecovered strain produced during each load-biased thermal cycle increased with increasing Pd content, during the initial thermal cycles. However, continued thermal cycling at constant stress resulted in a saturation of the work output and nearly eliminated further unrecovered strain under certain conditions, resulting in stable behavior amenable to many actuator applications.

  9. A comparative evaluation between new ternary zirconium alloys as alternative metals for orthopedic and dental prosthetic devices.

    Science.gov (United States)

    Shyti, Genti; Rosalbino, Francesco; Macciò, Daniele; Scarabelli, Linda; Quarto, Rodolfo; Giannoni, Paolo

    2014-02-01

    We assessed in vitro the corrosion behavior and biocompatibility of four Zr-based alloys (Zr97.5 Nb1.5VM1.0  ; VM, valve metal: Ti, Mo, W, Ta; at%) to be used as implant materials, comparing the results with grade-2 titanium, a biocompatible metal standard. Corrosion resistance was investigated by open circuit potential and electrochemical impedance spectroscopy measurements as a function of exposure time to an artificial physiological environment (Ringer's solution). Human bone marrow stromal cells were used to evaluate biocompatibility of the alloys and their influence on growth kinetics and cell osteogenic differentiation through histochemical and gene expression analyses. Open circuit potential values indicated that Zr-based alloys and grade-2 Ti undergo spontaneous passivation in the simulated aggressive environment. High impedance values for all samples demonstrated improved corrosion resistance of the oxide film, with the best protection characteristics displayed by Zr97.5  Nb1.5Ta1.0. Cells seeded on all surfaces showed the same growth kinetics, although matrix mineralization and alkaline phosphatase activity were maximal on Zr97.5  Nb1.5Mo1.0 and Zr97.5   Nb1.5Ta1.0. Markers of ongoing proliferation, however, such as podocalyxin and CD49f, were still overexpressed on Zr97.5   Nb1.5   Mo1.0 even upon osteoinduction. No relevant effects were noted for the CD146-expressing population of bone progenitors. Nonetheless, the presence of a more differentiated cell population on Zr97.5Nb1.5Ta1.0 samples was inferable by comparing mineralization data and transcript levels of osteogenic markers (osteocalcin, osteopontin, bone sialoprotein, and RUNX2). The combination of passivation, corrosion resistance and satisfactory biotolerance to bone progenitors make the Zr-based alloys promising implant materials. Among those we tested, Zr97.5Nb1.5Ta1.0 seems to be the most appealing.

  10. Crystal growth, characterization and photo detection properties of 2H–V0.75W0.25Se2 ternary alloy with 1T–VSe2 secondary phase

    Science.gov (United States)

    Pataniya, Pratik; Solanki, G. K.; Patel, K. D.; Pathak, V. M.; Sumesh, C. K.

    2017-10-01

    Transition metal chalcogenides have shown great potential for the applications in high performance optoelectronic devices. Here, we demonstrate for the first time the growth of V0.75W0.25Se2 van der Waals ternary alloy and its application in high performance photodetection. The crystals of V0.75W0.25Se2 were grown by direct vapour transport technique and chemical composition was confirmed by EDAX. The powder XRD results reveal the good crystallinity of grown samples, exhibits hexagonal lattice structure with P63/mmc space group. The XRD pattern also reveals the presence of 1T–VSe2 secondary phase. The SEM and TEM analysis are also carried out for structural analysis. The optical response, studied by photoluminescence spectroscopy discloses the various excitonic mechanisms of V0.75W0.25Se2 ternary alloy. The results of Raman spectroscopy discloses the presence of A 1g and E 2g modes of vibration and confirms the 2H-poly-type of grown V0.75W0.25Se2 ternary compound. The moderately fast time-resolved photoresponse is demonstrated under 670 nm laser light of power intensity 3 mW cm‑2 at 0.3 V bias voltage. The quantitative analysis of performance was carried out from the determined detector parameters such as response time, photo-responsivity, external quantum efficiency and detectivity.

  11. The Measurement and Interpretation of Transformation Temperatures in Nitinol

    Science.gov (United States)

    Duerig, T. W.; Pelton, A. R.; Bhattacharya, K.

    2017-12-01

    A previous paper (Duerig and Bhattacharya in Shap Mem Superelasticity 1:153-161, 2015) introduced several engineering considerations surrounding the R-phase in Nitinol and highlighted a common, if not pervasive, misconception regarding the use of the term Af by the medical device industry. This paper brings additional data to bear on the issue and proposes more accurate terminology. Moreover, a variety of tools are used to establish the forward and reverse stress-temperature phase diagrams for a superelastic wire typical of that used in medical devices. Once established, the two most common methods of measuring transformation temperatures, Differential Scanning Calorimetry and Bend Free Recovery, are tested against the observed behavior. Light is also shed upon the origin of the Clausius-Clapeyron ratio (d σ/d T), the triple point, and why such large variations are reported in superelastic alloys.

  12. Corrosion Resistance of Electroless Ni-Cu-P Ternary Alloy Coatings in Acidic and Neutral Corrosive Mediums

    Directory of Open Access Journals (Sweden)

    Mbouillé Cissé

    2010-01-01

    Full Text Available Electroless Ni-Cu-P alloy coatings were deposited on the ordinary steel substrate in an acidic hypophosphite-type plating bath. These coatings were characterized by a scanning electron microscope (SEM and an X-ray diffraction. The micrograph shows that coating presents a nodular aspect and is relatively homogeneous and very smooth. The EDX analysis shows that the coating contains 12 wt.% of phosphorus element with a predominance of nickel element. In addition, the anticorrosion properties of the Ni-Cu-P coatings in 1 M HCl, 1 M H2SO4, and 3% NaCl solutions were investigated using Tafel polarization curves, electrochemical impedance spectroscopy, and SEM/EDX analysis. The result showed a marginal improvement in corrosion resistance in 3% NaCl solution compared to acidic medium. It also showed that the corrosion mechanism depends on the nature of the solution.

  13. Theoretical investigation of structural, electronic and optical properties of MgxBa1-xS, MgxBa1-xSe and MgxBa1-xTe ternary alloys using DFT based FP-LAPW approach

    Science.gov (United States)

    Bhattacharjee, Rahul; Chattopadhyaya, Surya

    2017-11-01

    Density functional theory (DFT) based full-potential linearized augmented plane wave (FP-LAPW) methodology has been employed to investigate theoretically the structural, electronic and optical properties of MgxBa1-xS, MgxBa1-xSe and MgxBa1-xTe ternary alloys for 0 ≤ x ≤ 1 in their rock-salt (B1) crystallographic phase. The exchange-correlation potentials for the structural properties have been computed using the Wu-Cohen generalized-gradient approximation (WC-GGA) scheme, while those for the electronic and optical properties have been computed using both the WC-GGA and the recently developed Tran-Blaha modified Becke-Johnson (TB-mBJ) schemes. The thermodynamic stability of all the ternary alloys have been investigated by calculating their respective enthalpy of formation. The atomic and orbital origin of different electronic states in the band structure of the compounds have been identified from the respective density of states (DOS). Using the approach of Zunger and co-workers, the microscopic origin of band gap bowing has been discussed in term of volume deformation, charge exchange and structural relaxation. Bonding characteristics among the constituent atoms of each of the specimens have been discussed from their charge density contour plots. Optical properties of the binary compounds and ternary alloys have been investigated theoretically in terms of their respective dielectric function, refractive index, normal incidence reflectivity and optical conductivity. Several calculated results have been compared with available experimental and other theoretical data.

  14. Microstructural characterization and phase transformation of ternary alloys near at Al{sub 3}Ti compound; Caracterizacion microestructural y transformaciones de fase de aleaciones ternareas cercanas al compuesto Al{sub 3}Ti

    Energy Technology Data Exchange (ETDEWEB)

    Angeles Ch, C. [Instituto Nacional de Investigaciones Nucleares. Depto.de Sintesis y Caracterizacion de Materiales. Carretera Mexico-Toluca Km. 36.5 C.P. 52045, Ocoyoacac, Edo. de Mexico (Mexico)

    1999-07-01

    This research work is related with the structural characteristic and compositional values of the crystalline phases, which are found in ternary alloys of Ti-Al-Fe and TI-Al-Cu. These types of alloys were obtained using a rapid solidification technique (10{sup 3}-10{sup 4} K/s) and pure elements such as Al, Ti, Fe and Cu (99.99%). These cooling velocities allow the formation of stable phases and small grain sizes (approximately in range of a few micras). The obtained results indicate the presence of Al{sub 3}Ti and others phases of L1{sub 2} type. These phases are commonly found in a matrix rich in A1. The microalloyed elements (Cu and Fe) substitute the aluminum in both kinds of phases. Alloys with low content of Cu show transition states from the tetragonal structure DO{sub 22} to the cubic phases L1{sub 2}. The structural characteristics of the alloys are related with some microhardness measurement. The results show that the presence of the L1{sub 2} phase tends to increase to hardness depending of the content of this phase.

  15. Low-temperature sequential pulsed chemical vapor deposition of ternary B{sub x}Ga{sub 1-x}N and B{sub x}In{sub 1-x}N thin film alloys

    Energy Technology Data Exchange (ETDEWEB)

    Haider, Ali, E-mail: ali.haider@bilkent.edu.tr, E-mail: biyikli@unam.bilkent.edu.tr; Kizir, Seda; Ozgit-Akgun, Cagla; Biyikli, Necmi, E-mail: ali.haider@bilkent.edu.tr, E-mail: biyikli@unam.bilkent.edu.tr [National Nanotechnology Research Center (UNAM), Bilkent University, Bilkent, Ankara 06800, Turkey and Institute of Materials Science and Nanotechnology, Bilkent University, Bilkent, Ankara 06800 (Turkey); Okyay, Ali Kemal [National Nanotechnology Research Center (UNAM), Bilkent University, Bilkent, Ankara 06800 (Turkey); Institute of Materials Science and Nanotechnology, Bilkent University, Bilkent, Ankara 06800 (Turkey); Department of Electrical and Electronics Engineering, Bilkent University, Bilkent, Ankara 06800 Turkey (Turkey)

    2016-01-15

    In this work, the authors have performed sequential pulsed chemical vapor deposition of ternary B{sub x}Ga{sub 1-x}N and B{sub x}In{sub 1-x}N alloys at a growth temperature of 450 °C. Triethylboron, triethylgallium, trimethylindium, and N{sub 2} or N{sub 2}/H{sub 2} plasma have been utilized as boron, gallium, indium, and nitrogen precursors, respectively. The authors have studied the compositional dependence of structural, optical, and morphological properties of B{sub x}Ga{sub 1-x}N and B{sub x}In{sub 1-x}N ternary thin film alloys. Grazing incidence X-ray diffraction measurements showed that boron incorporation in wurtzite lattice of GaN and InN diminishes the crystallinity of B{sub x}Ga{sub 1-x}N and B{sub x}In{sub 1-x}N sample. Refractive index decreased from 2.24 to 1.65 as the B concentration of B{sub x}Ga{sub 1-x}N increased from 35% to 88%. Similarly, refractive index of B{sub x}In{sub 1-x}N changed from 1.98 to 1.74 for increase in B concentration value from 32% to 87%, respectively. Optical transmission band edge values of the B{sub x}Ga{sub 1-x}N and B{sub x}In{sub 1-x}N films shifted to lower wavelengths with increasing boron content, indicating the tunability of energy band gap with alloy composition. Atomic force microscopy measurements revealed an increase in surface roughness with boron concentration of B{sub x}Ga{sub 1-x}N, while an opposite trend was observed for B{sub x}In{sub 1-x}N thin films.

  16. Electrochemical Properties of Ni 47 Ti 49 Co 4 Shape Memory Alloy in Artificial Urine for Urological Implant

    KAUST Repository

    Ahmed, Rasha A.

    2015-09-02

    © 2015 American Chemical Society. The corrosion performance of Ni47Ti49Co4 shape memory alloys (SMA) in artificial urine solution was evaluated in comparison with Ni51Ti49 alloy as reference, at 37°C and pH 5.6-6.4. SEM results revealed less pitting attack for Ni47Ti49Co4 SMA surface after immersion in artificial urine solution. The XRD analysis demonstrated the formation of passive film on Ni47Ti49Co4 SMA. The XPS analysis indicated that the film mainly consisted of O, Ti, Co, P, and a small amount of Ni, and the concentration of Ni ions release was greatly reduced compared to that of the Ni51Ti49 SMA. Linear polarization results illustrated that corrosion potential (Ecorr), corrosion current density (icorr), and ac polarization resistance (Rp) were affected greatly by alloying Co to Nitinol alloy. Our observations indicated that the corrosion resistance of the ternary alloy, Ni47Ti49Co4 SMA, offers superior corrosion resistance in artificial urine when compared to Ni51Ti49 SMA, which was suitable for medical applications.

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

    Science.gov (United States)

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

    2009-01-01

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

  18. Comparative study on corrosion behaviour of Nitinol and stainless steel orthodontic wires in simulated saliva solution in presence of fluoride ions.

    Science.gov (United States)

    Mirjalili, M; Momeni, M; Ebrahimi, N; Moayed, M H

    2013-05-01

    Localized corrosion and effects of pre-passivation treatment of Nitinol and SS304 orthodontic wires in simulated saliva solution in the presence and absence of fluoride ions were investigated by means of potentiodynamic and potentiostatic polarisations. Results revealed that Nitinol does not show pitting corrosion in saliva solution however, SS304 shows pitting corrosion. Meanwhile fluoride ion has deteriorative effect on pitting corrosion of Nitinol, while its effect on SS304 was marginally constructive. Additionally, the presence of artificial crevice has no effect on corrosion behaviour in the presence of fluoride. Pre-passivation treatment has positive influence on pitting corrosion of both alloys in the presence of F(-) ions. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Formation of ternary Mg–Cu–Dy bulk metallic glasses

    Indian Academy of Sciences (India)

    Administrator

    Abstract. The glass-forming ability (GFA) of ternary Mg–Cu–Dy alloys was systematically investigated by using differential scanning calorimetry (DSC) and X-ray diffractometry (XRD) techniques. The results showed that a series of ternary Mg–Cu–Dy bulk metallic glasses (BGMs) with a diameter of 4–8 mm were suc-.

  20. Carbon fibre and nitinol needles for MRI-guided interventions: First in vitro and in vivo application

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Christoph, E-mail: Christoph.thomas@med.uni-tuebingen.de [Department of Diagnostic and Interventional Radiology, University of Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tuebingen (Germany); Wojtczyk, Hanne [Section of Experimental Radiology, University of Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tuebingen (Germany); Rempp, Hansjoerg; Clasen, Stephan; Horger, Marius [Department of Diagnostic and Interventional Radiology, University of Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tuebingen (Germany); Lassberg, Christoph von [Department of Sports Medicine, University of Tuebingen, Silcherstrasse 5, 72076 Tuebingen (Germany); Fritz, Jan [Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD 21287 (United States); Claussen, Claus D. [Department of Diagnostic and Interventional Radiology, University of Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tuebingen (Germany); Pereira, Philippe L. [Department of Radiology, Minimally Invasive Therapies and Nuclearmedicine, SLK-Kliniken Heilbronn GmbH, Am Gesundbrunnen 20-26, 74078 Heilbronn (Germany)

    2011-09-15

    Objective: To assess the artefact properties of a MR-compatible carbon fibre needle with a nitinol mandrin in vitro and to report first clinical experiences. Materials and methods: In vitro, the carbon fibre/nitinol needle was imaged at different angles against the main magnetic field (1.5 T open bore magnet). A gradient echo MR fluoroscopy sequence (GRE: TR 9.3 ms, TE 3.12 ms, bandwidth 200 Hz/pixel, flip-angle 12{sup o}) and a fast turbo spin echo sequence (FSE: TR 412 ms, TE 9.7 ms, bandwidth 200 Hz/pixel, flip-angle 150{sup o}) were used. Artefact width, needle intensity contrast and needle tip location errors were assessed. In vivo, lumbar periradicular corticosteroid injections and one sclerotherapy were performed with carbon fibre needles (10 procedures) and with titanium alloy needles (2 procedures). The artefact sizes and contrasts were measured. Results: In vitro, artefact diameters of the carbon fibre needle ranged from 3.3 to 4.6 mm, contrasts from 0.11 to 0.52, with larger artefact contrasts and widths with the GRE sequence. Needle tip location errors of -2.1 to -2.8 mm were observed. Decreasing angles to the main field lead to smaller artefacts. In vivo, the carbon fibre/nitinol needle produced smaller artefacts (mean width FSE/GRE: 2.8 mm/4.6 mm) with lower contrast (0.30-0.42) than the titanium alloy needle (mean width FSE/GRE: 4.1 mm/7.5 mm, contrast 0.60-0.73). Conclusions: The carbon fibre/nitinol needle is useful for performing MR-guided interventions at 1.5 T, producing more subtle artefacts than a titanium alloy needle, but with an incomplete depiction and thus inaccurate localization of the needle tip.

  1. Sodium Hypochlorite Treatment and Nitinol Performance for Medical Devices

    Science.gov (United States)

    Weaver, J. D.; Gutierrez, E. J.; Nagaraja, S.; Stafford, P. R.; Sivan, S.; Di Prima, M.

    2017-09-01

    Processing of nitinol medical devices has evolved over the years as manufacturers have identified methods of reducing surface defects such as inclusions. One recent method proposes to soak nitinol medical devices in a 6% sodium hypochlorite (NaClO) solution as a means of identifying surface inclusions. Devices with surface inclusions could in theory then be removed from production because inclusions would interact with NaClO to form a visible black material on the nitinol surface. To understand the effects of an NaClO soak on performance, we compared as-received and NaClO-soaked nitinol wires with two different surface finishes (black oxide and electropolished). Pitting corrosion susceptibility was equivalent between the as-received and NaClO-soaked groups for both surface finishes. Nickel ion release increased in the NaClO-soaked group for black oxide nitinol, but was equivalent for electropolished nitinol. Fatigue testing revealed a lower fatigue life for NaClO-soaked black oxide nitinol at all alternating strains. With the exception of 0.83% alternating strain, NaClO-soaked and as-received electropolished nitinol had similar average fatigue life, but the NaClO-soaked group showed higher variability. NaClO-soaked electropolished nitinol had specimens with the lowest number of cycles to fracture for all alternating strains tested with the exception of the highest alternating strain 1.2%. The NaClO treatment identified only one specimen with surface inclusions and caused readily identifiable surface damage to the black oxide nitinol. Damage from the NaClO soak to electropolished nitinol surface also appears to have occurred and is likely the cause of the increased variability of the fatigue results. Overall, the NaClO soak appears to not lead to an improvement in nitinol performance and seems to be damaging to the nitinol surface in ways that may not be detectable with a simple visual inspection for black material on the nitinol surface.

  2. An overview of thin film nitinol endovascular devices.

    Science.gov (United States)

    Shayan, Mahdis; Chun, Youngjae

    2015-07-01

    Thin film nitinol has unique mechanical properties (e.g., superelasticity), excellent biocompatibility, and ultra-smooth surface, as well as shape memory behavior. All these features along with its low-profile physical dimension (i.e., a few micrometers thick) make this material an ideal candidate in developing low-profile medical devices (e.g., endovascular devices). Thin film nitinol-based devices can be collapsed and inserted in remarkably smaller diameter catheters for a wide range of catheter-based procedures; therefore, it can be easily delivered through highly tortuous or narrow vascular system. A high-quality thin film nitinol can be fabricated by vacuum sputter deposition technique. Micromachining techniques were used to create micro patterns on the thin film nitinol to provide fenestrations for nutrition and oxygen transport and to increase the device's flexibility for the devices used as thin film nitinol covered stent. In addition, a new surface treatment method has been developed for improving the hemocompatibility of thin film nitinol when it is used as a graft material in endovascular devices. Both in vitro and in vivo test data demonstrated a superior hemocompatibility of the thin film nitinol when compared with commercially available endovascular graft materials such as ePTFE or Dacron polyester. Promising features like these have motivated the development of thin film nitinol as a novel biomaterial for creating endovascular devices such as stent grafts, neurovascular flow diverters, and heart valves. This review focuses on thin film nitinol fabrication processes, mechanical and biological properties of the material, as well as current and potential thin film nitinol medical applications. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  3. Electrochemical, Polarization, and Crevice Corrosion Testing of Nitinol 60, A Supplement to the ECLSS Sustaining Materials Compatibility Study

    Science.gov (United States)

    Lee, R. E.

    2016-01-01

    In earlier trials, electrochemical test results were presented for six noble metals evaluated in test solutions representative of waste liquids processed in the Environmental Control and Life Support System (ECLSS) aboard the International Space Station (ISS). Subsequently, a seventh metal, Nitinol 60, was added for evaluation and subjected to the same test routines, data analysis, and theoretical methodologies. The previous six test metals included three titanium grades, (commercially pure, 6Al-4V alloy and 6Al-4V low interstitial alloy), two nickel-chromium alloys (Inconel(RegisteredTrademark) 625 and Hastelloy(RegisteredTrademark) C276), and one high-tier stainless steel (Cronidur(RegisteredTrademark) 30). The three titanium alloys gave the best results of all the metals, indicating superior corrosive nobility and galvanic protection properties. For this current effort, the results have clearly shown that Nitinol 60 is almost as noble as titanium, being very corrosion-resistant and galvanically compatible with the other six metals electrochemically and during long-term exposure. is also quite noble as it is very corrosion resistant and galvanically compatible with the other six metals from both an electrochemical perspective and long-term crevice corrosion scenario. This was clearly demonstrated utilizing the same techniques for linear, Tafel and cyclic polarization, and galvanic coupling of the metal candidate as was done for the previous study. The high nobility and low corrosion susceptibility for Nitinol 60 appear to be intermediate to the nickel/chromium alloys and the titanium metals with indications that are more reflective of the titanium metals in terms of general corrosion and pitting behavior.

  4. Influence of Nitinol wire surface treatment on oxide thickness and composition and its subsequent effect on corrosion resistance and nickel ion release.

    Science.gov (United States)

    Clarke, B; Carroll, W; Rochev, Y; Hynes, M; Bradley, D; Plumley, D

    2006-10-01

    Medical implants and devices are now used successfully in surgical procedures on a daily basis. Alloys of nickel and titanium, and in particular Nitinol are of special interest in the medical device industry, because of their shape memory and superelastic properties. The corrosion behavior of nitinol in the body is also of critical importance because of the known toxicological effects of nickel. The stability of a NiTi alloy in the physiological environment is dependant primarily on the properties of the mostly TiO(2) oxide layer that is present on the surface. For the present study, a range of nitinol wires have been prepared using different drawing processes and a range of surface preparation procedures. It is clear from the results obtained that the wire samples with very thick oxides also contain a high nickel content in the oxide layer. The untreated samples with the thicker oxides show the lowest pitting potential values and greater nickel release in both long and short-term experiments. It was also found that after long-term immersion tests breakdown potentials increased for samples that exhibited lower values initially. From these results it would appear that surface treatment is essential for the optimum bioperformance of nitinol. (c) 2006 Wiley Periodicals, Inc

  5. Mechanical response of proton beam irradiated nitinol

    Energy Technology Data Exchange (ETDEWEB)

    Afzal, Naveed [Centre for Advanced Studies in Physics, GC University, Lahore (Pakistan); Ghauri, I.M., E-mail: ijaz.phys@gmail.co [Centre for Advanced Studies in Physics, GC University, Lahore (Pakistan); Mubarik, F.E.; Amin, F. [Centre for Advanced Studies in Physics, GC University, Lahore (Pakistan)

    2011-01-01

    The present investigation deals with the study of mechanical behavior of proton beam irradiated nitinol at room temperature. The specimens in austenitic phase were irradiated over periods of 15, 30, 45 and 60 min at room temperature using 2 MeV proton beam obtained from Pelletron accelerator. The stress-strain curves of both unirradiated and irradiated specimens were obtained using a universal testing machine at room temperature. The results of the experiment show that an intermediate rhombohedral (R) phase has been introduced between austenite and martensite phase, which resulted in the suppression of direct transformation from austenite to martensite (A-M). Stresses required to start R-phase ({sigma}{sub RS}) and martensitic phase ({sigma}{sub MS}) were observed to decrease with increase in exposure time. The hardness tests of samples before and after irradiation were also carried out using Vickers hardness tester. The comparison reveals that the hardness is higher in irradiated specimens than that of the unirradiated one. The increase in hardness is quite sharp in specimens irradiated for 15 min, which then increases linearly as the exposure time is increased up to 60 min. The generation of R-phase, variations in the transformation stresses {sigma}{sub RS} and {sigma}{sub MS} and increase in hardness of irradiated nitinol may be attributed to lattice disorder and associated changes in crystal structure induced by proton beam irradiation.

  6. Shape memory alloys: metallurgy, biocompatibility, and biomechanics for neurosurgical applications.

    Science.gov (United States)

    Hoh, Daniel J; Hoh, Brian L; Amar, Arun P; Wang, Michael Y

    2009-05-01

    SHAPE MEMORY ALLOYS possess distinct dynamic properties with particular applications in neurosurgery. Because of their unique physical characteristics, these materials are finding increasing application where resiliency, conformation, and actuation are needed. Nitinol, the most frequently manufactured shape memory alloy, responds to thermal and mechanical stimuli with remarkable mechanical properties such as shape memory effect, super-elasticity, and high damping capacity. Nitinol has found particular use in the biomedical community because of its excellent fatigue resistance and biocompatibility, with special interest in neurosurgical applications. The properties of nitinol and its diffusionless phase transformations contribute to these unique mechanical capabilities. The features of nitinol, particularly its shape memory effect, super-elasticity, damping capacity, as well as its biocompatibility and biomechanics are discussed herein. Current and future applications of nitinol and other shape memory alloys in endovascular, spinal, and minimally invasive neurosurgery are introduced. An understanding of the metallurgic properties of nitinol provides a foundation for further exploration of its use in neurosurgical implant design.

  7. Synthesis of Ternary Nitrides From Intermetallic Precursors: Modes of Nitridation in Model Cr3Pt Alloys to Form Cr3PtN Perovskite and Applications to Other Systems

    Energy Technology Data Exchange (ETDEWEB)

    Brady, Michael P [ORNL; Wrobel, Sarah [University of Tennessee, Knoxville (UTK); Lograsso, Tom [Ames Laboratory; Payzant, E Andrew [ORNL; Hoelzer, David T [ORNL; Horton Jr, Joe A [ORNL; Walker, Larry R [ORNL

    2004-01-01

    The use of intermetallic alloy precursors is explored as a new means to synthesize complex transition and refractory metal nitrides, carbides, and related phases. The conditions under which model single-phase Cr{sub 3}Pt and two-phase Cr{sub 3}Pt-dispersed Cr alloys form Cr{sub 3}PtN antiperovskite when thermally nitrided were studied. Phenomenological experiments suggest that the key variable to achieving single-phase Cr{sub 3}PtN surface layers is the Cr{sub 3}Pt phase composition. In two-phase {beta}-Cr-Cr{sub 3}Pt alloys, the formation of single-phase Cr{sub 3}PtN at Cr{sub 3}Pt precipitates by in-place internal nitridation was found to be a strong function of the size of the Cr{sub 3}Pt dispersion in the microstructure. Nanoscale Cr{sub 3}Pt dispersions were readily converted to near single-phase Cr{sub 3}PtN, whereas nitridation of coarse Cr{sub 3}Pt particles resulted in a cellular or discontinuous-type reaction to form a lath mixture of Cr{sub 3}PtN and a more Cr-rich Cr{sub 3}Pt or {beta}-Cr. The potential for using such external/internal oxidation phenomena as a synthesis approach to layered or composite surfaces of ternary ceramic phases (nitrides, carbides, borides, etc.) of technological interest such as the Ti{sub 3}AlC{sub 2} phase, bimetallic nitride, and carbide catalysts (Co{sub 3}Mo{sub 3}N and Co{sub 3}Mo{sub 3}C and related phases), and magnetic rare earth nitrides (Fe{sub 17}Sm{sub 2}N{sub x} or Fe{sub 17}Nd{sub 2}N{sub x}) is discussed.

  8. Effect of surface etching and electrodeposition of copper on nitinol

    Science.gov (United States)

    Ramos-Moore, E.; Rosenkranz, A.; Matamala, L. F.; Videla, A.; Durán, A.; Ramos-Grez, J.

    2017-10-01

    Nitinol-based materials are very promising for medical and dental applications since those materials can combine shape memory, corrosion resistance, biocompatibility and antibacterial properties. In particular, surface modifications and coating deposition can be used to tailor and to unify those properties. We report preliminary results on the study of the effect of surface etching and electrodeposition of Copper on Nitinol using optical, chemical and thermal techniques. The results show that surface etching enhances the surface roughness of Nitinol, induces the formation of Copper-based compounds at the Nitinol-Copper interface, reduces the austenitic-martensitic transformations enthalpies and reduces the Copper coating roughness. Further studies are needed in order to highlight the influence of the electrodeposited Copper on the memory shape properties of NiTi.

  9. Nitinol Fatigue Life for Variable Strain Amplitude Fatigue

    Science.gov (United States)

    Lin, Z.; Pike, K.; Schlun, M.; Zipse, A.; Draper, J.

    2012-12-01

    Nitinol fatigue testing results are presented for variable strain amplitude cycling. The results indicate that cycles smaller than the constant amplitude fatigue limit may contribute to significant fatigue damage when they occur in a repeating sequence of large and small amplitude cycles. The testing utilized two specimen types: stent-like diamond specimens and Z-shaped wire specimens. The diamond specimens were made from nitinol tubing with stent-like manufacturing processes and the Z-shaped wire specimens were made from heat set nitinol wire. The study explored the hypothesis that duty cycling can have an effect on nitinol fatigue life. Stent-like structures were subjected to different in vivo loadings in order to create more complex strain amplitudes. The main focus in this study was to determine whether a combination of small and large amplitudes causes additional damage that alters the fatigue life of a component.

  10. A precious metal alloy for construction of MR imaging-compatible balloon-expandable vascular stents

    NARCIS (Netherlands)

    L.C. van Dijk (Lukas); J. van Holten; B.P. van Dijk (Bastiaan); N.A. Matheijssen; P.M.T. Pattynama (Peter)

    2001-01-01

    textabstractThe authors developed ABI alloy, which mechanically resembles stainless steel 316. The main elements of ABI alloy are palladium and silver. Magnetic resonance (MR) images and radiographs of ABI alloy and stainless steel 316 stent models and of nitinol, tantalum, and

  11. Effect of a novel load-bearing trabecular Nitinol scaffold on rabbit radius bone regeneration

    Science.gov (United States)

    Gotman, Irena; Zaretzky, Asaph; Psakhie, Sergey G.; Gutmanas, Elazar Y.

    2015-10-01

    The research aim was to evaluate the bone regeneration capability of novel load-bearing NiTi alloy (Nitinol) scaffolds in a critical-size defect (CSD) model. High strength "trabecular Nitinol" scaffolds were prepared by PIRAC (Powder Immersion Reaction Assisted Coating) annealing of the highly porous Ni foam in Ti powder at 900°C. This was followed by PIRAC nitriding to mitigate the release of potentially toxic Ni ions. Scaffolds phase composition and microstructure were characterized by X-ray diffraction and scanning electron microscopy (SEM/EDS), and their mechanical properties were tested in compression. New Zealand white rabbits received bone defect in right radius and were divided in four groups randomly. In the control group, nothing was placed in the defect. In other groups, NiTi scaffolds were implanted in the defect: (i) as produced, (ii) loaded with bone marrow aspirate (BMA), and (iii) biomimetically CaP-coated. The animals were sacrificed after 12 weeks. The forelimbs with scaffolds were resected, fixed, sectioned and examined in SEM. New bone formation inside the scaffold was studied by EDS analysis and by the processing of backscattered electron images. Bone ingrowth into the scaffold was observed in all implant groups, mostly next to the ulna. New bone formation was strongly enhanced by BMA loading and biomimeatic CaP coating, the bone penetrating as much as 1-1.5 mm into the scaffold. The results of this preliminary study demonstrate that the newly developed high strength trabecular Nitinol scaffolds can be successfully used for bone regeneration in critical size defects.

  12. Hierarchical periodic micro/nano-structures on nitinol and their influence on oriented endothelialization and anti-thrombosis

    Energy Technology Data Exchange (ETDEWEB)

    Nozaki, Kosuke [Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-Surugadai, Chiyoda, Tokyo 101-0062 (Japan); Shinonaga, Togo [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Ebe, Noriko; Horiuchi, Naohiro; Nakamura, Miho; Tsutsumi, Yusuke; Hanawa, Takao [Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-Surugadai, Chiyoda, Tokyo 101-0062 (Japan); Tsukamoto, Masahiro [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Yamashita, Kimihiro [Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-Surugadai, Chiyoda, Tokyo 101-0062 (Japan); Nagai, Akiko, E-mail: nag-bcr@tmd.ac.jp [Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-Surugadai, Chiyoda, Tokyo 101-0062 (Japan)

    2015-12-01

    The applications of hierarchical micro/nano-structures, which possess properties of two-scale roughness, have been studied in various fields. In this study, hierarchical periodic micro/nano-structures were fabricated on nitinol, an equiatomic Ni–Ti alloy, using a femtosecond laser for the surface modification of intravascular stents. By controlling the laser fluence, two types of surfaces were developed: periodic nano- and micro/nano-structures. Evaluation of water contact angles indicated that the nano-surface was hydrophilic and the micro/nano-surface was hydrophobic. Endothelial cells aligned along the nano-structures on both surfaces, whereas platelets failed to adhere to the micro/nano-surface. Decorrelation between the responses of the two cell types and the results of water contact angle analysis were a result of the pinning effect. This is the first study to show the applicability of hierarchical periodic micro/nano-structures for surface modification of nitinol. - Highlights: • Hierarchical micro/nano-structures were created on nitinol using a femtosecond laser. • The nano-surface was hydrophilic and the micro/nano-surface was hydrophobic. • Endothelial cells aligned along the nano-structures • Platelets failed to adhere to the micro/nano-surface.

  13. Biomedical engineering in design and application of nitinol stents with shape memory effect

    Science.gov (United States)

    Ryklina, E. P.; Khmelevskaya, I. Y.; Morozova, Tamara V.; Prokoshkin, S. D.

    1996-04-01

    Our studies in the field of endosurgery in collaboration with the physicians of the National Research Center of Surgery of the Academy of Medical Sciences are carried out beginning in 1983. These studies laid the foundation for the new direction of X-ray surgery--X-ray Nitinol stenting of vessels and tubular structures. X-ray nitinol stents are unique self-fixing shells based on the shape memory effect and superelasticity of nickel-titanium alloys self- reconstructed under human body temperature. Applied for stenting of arteries in cases of stenosis etc., bile ducts in cases of benign and malignant stenoses, digestive tract in cases of oesophageal cancer and cervical canal uterus in cases of postsurgical atresiss and strictures of uterine. The purpose of stenting is restoration of the shape of artery or tubular structure by a cylinder frame formation. The especially elaborated original method of stenting allows to avoid the traditional surgical operation, i.e. the stenting is performed without blood, narcosis and surgical knife. The stent to be implanted is transported into the affected zone through the puncture under the X-ray control. Clinical applications of X-ray endovascular stenting has been started in March 1984. During this period nearly 400 operations on stenting have been performed on femoral, iliac, brachio-cephalic, subclavian arteries, bile ducts, tracheas, digestive tract and cervical canal uterus.

  14. A novel bending fatigue test device based on self-excited vibration principle and its application to superelastic Nitinol microwire study

    Science.gov (United States)

    Leng, Jiaming; Yan, Xiaojun; Zhang, Xiaoyong; Qi, Mingjing; Liu, Zhiwei; Huang, Dawei

    2017-10-01

    Most Nitinol-alloy-based biomedical devices are usually manufactured from straight drawn microwires or microbeams. Fatigue due to cyclic bending is interpreted as the primary failure mechanism in these devices. However, the bending fatigue performance of a Nitinol microwire is rarely studied because of the lack of test devices. Therefore, we firstly establish a bending fatigue test device based on the self-excited vibration principle. Then, we further improve and experimentally verify the device in three aspects to enlarge the strain amplitude: electrode distance optimization, electrode placement angle optimization and local stiffness enhancement. Based on these improvements, the strain amplitude is increased to 6%, successfully meeting the requirements of Nitinol microwire bending fatigue tests. Using the improved test device, a group of superelastic Nitinol (55.8% Ni-44.2% Ti) microwires with a diameter of 50.8 μm are tested. The test results show that the fatigue strain limit for the chosen life (1 × 106 cycles) is around 1.9%, and the inflexion appears at a strain amplitude of 2.3%. SEM observation shows the typical features of low-cycle and high-cycle fatigue on the fracture surfaces.

  15. The role of bismuth on the microstructure and corrosion behavior of ternary Mg–1.2Ca–xBi alloys for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Tok, H.Y.; Hamzah, E., E-mail: Esah@fkm.utm.my; Bakhsheshi-Rad, H.R.

    2015-08-15

    Highlights: • Secondary phases have a significant effect on corrosion properties of the alloys. • Microstructure of Mg–Ca–xBi was refined significantly after Bi addition. • Addition of 0.5 wt.% Bi to Mg–Ca alloy leads to increase corrosion resistance. • Microstructure analysis showed needle-shaped precipitates at the grain boundaries. - Abstract: In this study the influence of various Bi additions on the microstructure and corrosion behavior of the Mg–1.2Ca–xBi alloys (x = 0.5, 1.5, 3, 5, 12 wt.%) were evaluated by using optical and scanning electron microscopy, immersion and electrochemical tests. Microstructural observations showed that the refinement efficiency became more pronounced with increased Bi amount. Microstructural results of Mg–1.2Ca–xBi (x = 0.5, 1.5, and 3) indicated that the formation of three distinct phases—namely α-Mg, Mg{sub 2}Ca and Mg{sub 3}Bi{sub 2}. However, further addition of Bi to 5 and 12 wt.% leads to evolution of α-Mg, Mg{sub 3}Bi{sub 2}, and Mg{sub 2}Bi{sub 2}Ca phases. The addition of Bi up to 0.5 wt.% enhanced corrosion resistance while further addition from 1.5 to 12 wt.% accelerated the degradation rate because of the emergence of more galvanic coupling between the α-Mg phases and secondary phases. The analyses showed that the Mg–1.2Ca–0.5Bi alloy gives the best corrosion resistance behavior, which makes it ideal for biodegradable medical applications.

  16. Liquid phase separation and rapid dendritic growth of highly undercooled ternary Fe62.5Cu27.5Sn10 alloy

    Science.gov (United States)

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

    2015-02-01

    The phase separation and dendritic growth characteristics of undercooled liquid Fe62.5Cu27.5Sn10 alloy have been investigated by glass fluxing and drop tube techniques. Three critical bulk undercoolings of microstructure evolution are experimentally determined as 7, 65, and 142 K. Equilibrium peritectic solidification proceeds in the small undercooling regime below 7 K. Metastable liquid phase separation takes place if bulk undercooling increases above 65 K. Remarkable macroscopic phase separation is induced providing that bulk undercooling overtakes the third threshold of 142 K. With the continuous increase of bulk undercooling, the solidified microstructure initially appears as well-branched dendrites, then displays microscale segregation morphology, and finally evolves into macrosegregation patterns. If alloy undercooling is smaller than 142 K, the dendritic growth velocity of γFe phase varies with undercooling according to a power function relationship. Once bulk undercooling exceeds 142 K, its dendritic growth velocity increases exponentially with undercooling, which reaches 30.4 m/s at the maximum undercooling of 360 K (0.21TL). As a comparative study, the liquid phase separation of Fe62.5Cu27.5Sn10 alloy droplets is also explored under the free fall condition. Theoretical calculations reveal that the thermal and solutal Marangoni migrations are the dynamic mechanisms responsible for the development of core-shell structure.

  17. Phase field crystal modeling of ternary solidification microstructures

    OpenAIRE

    Berghoff, Marco; Nestler, Britta

    2015-01-01

    In the present work, we present a free energy derivation of the multi-component phase-field crystal model [1] and illustrate the capability to simulate dendritic and eutectic solidification in ternary alloys. Fast free energy minimization by a simulated annealing algorithm of an approximated crystal is compared with the free energy of a fully simulated phase field crystal structure. The calculation of ternary phase diagrams from these free energies is described. Based on the free energies rel...

  18. Panchromatic Sequentially Cast Ternary Polymer Solar Cells.

    Science.gov (United States)

    Ghasemi, Masoud; Ye, Long; Zhang, Qianqian; Yan, Liang; Kim, Joo-Hyun; Awartani, Omar; You, Wei; Gadisa, Abay; Ade, Harald

    2017-01-01

    A sequential-casting ternary method is developed to create stratified bulk heterojunction (BHJ) solar cells, in which the two BHJ layers are spin cast sequentially without the need of adopting a middle electrode and orthogonal solvents. This method is found to be particularly useful for polymers that form a mechanically alloyed morphology due to the high degree of miscibility in the blend. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Rapid, Reliable Shape Setting of Superelastic Nitinol for Prototyping Robots.

    Science.gov (United States)

    Gilbert, Hunter B; Webster, Robert J

    Shape setting Nitinol tubes and wires in a typical laboratory setting for use in superelastic robots is challenging. Obtaining samples that remain superelastic and exhibit desired precurvatures currently requires many iterations, which is time consuming and consumes a substantial amount of Nitinol. To provide a more accurate and reliable method of shape setting, in this paper we propose an electrical technique that uses Joule heating to attain the necessary shape setting temperatures. The resulting high power heating prevents unintended aging of the material and yields consistent and accurate results for the rapid creation of prototypes. We present a complete algorithm and system together with an experimental analysis of temperature regulation. We experimentally validate the approach on Nitinol tubes that are shape set into planar curves. We also demonstrate the feasibility of creating general space curves by shape setting a helical tube. The system demonstrates a mean absolute temperature error of 10°C.

  20. Thermodynamic Study of Sn-Bi-Nd, Tb Ternary Systems

    Science.gov (United States)

    Xu, F.; Chen, Y. T.; Ye, R.; Chen, Y. Y.; Su, X. H.; Wang, S. L.; Fu, C. Y.

    2017-09-01

    The aim of this study was to investigate the effect of the addition of rare earth elements on Sn-Bi-based alloy, and to study the phase equilibrium of Sn-Bi-Nd, Tb ternary systems by means of establishing the thermodynamic database. Combined with the thermodynamic parameters of relevant binary systems, the thermodynamic database of the Sn-Bi-Nd, Tb ternary systems has been developed to present the significant information for the design of low-temperature lead-free solder alloys.

  1. First principles calculation of electronic structure, bonding and chemical stability of TiB 2, NbB 2 and their ternary alloy Ti 0.5Nb 0.5B 2

    Science.gov (United States)

    Hamdad, N.; Benosman, N.; Bouhafs, B.

    2010-01-01

    The metal diboride family has been systematically studied in recent years due to the discovery of superconductivity for magnesium diboride MgB 2 at 39 K. TiB 2 is the most stable of several titanium-boron compounds, due to its high hardness, extreme melting point and chemical inertness. TiB 2 is a candidate for a number of applications; it is used for wear parts and in composites with other materials. In combination with other primarily oxide ceramics, TiB 2 is used to constitute composite materials in which the presence of the material serves to increase the strength and fracture toughness of the matrix. In our paper, the electronic structure of AlB 2-type transition metal diboride of TiB 2, NbB 2 and their ternary alloy Ti 0.5Nb 0.5B 2 have been calculated by using the full potential linearized augmented plane wave method with local orbitals (APW+ lo). We included the exchange correlation potential by using both the generalized gradient approximation (GGA) and the local density approximation (LDA), respectively, as embodied in the Wien2 K in full relativistic version. The electronic structure is discussed and the rigid band model is shown to provide a fairly good description. The Ti-3d and Nb-4d electron are treated as valence electrons. We explained in some detail the bonding nature of our compounds. The existence of the pseudogap in the total densities is found to be a common feature of these compounds, but we found that the pseudogap at Fermi-levels of TiB 2 is the competing effect of Ti-3d resonance and strong hybridization between Ti-3d and B-2p states. The variation of the chemical stabilities of these diborides is analysed. The results are compared with other theoretical and experimental work.

  2. Calculated site substitution in ternary gamma'-Ni3Al: Temperature and composition effects

    DEFF Research Database (Denmark)

    Ruban, Andrei; Skriver, Hans Lomholt

    1997-01-01

    The temperature and composition dependence of the site substitution behavior of ternary additions to Ni3Al is examined on the basis of first-principles calculations of the total energies of ternary, partially ordered (gamma') alloys. The calculations are performed by means of the linear muffin...

  3. Carbon/Ternary Alloy/Carbon Optical Stack on Mylar as an Optical Data Storage Medium to Potentially Replace Magnetic Tape

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hao; Lunt, Barry M.; Gates, Richard J.; Asplund, Matthew C.; Shutthanandan, V.; Davis, Robert C.; Linford, Matthew R.

    2013-09-11

    A novel write-once-read-many (WORM) optical stack on Mylar tape is proposed as a replacement for magnetic tape for archival data storage. This optical tape contains a cosputtered bismuth–tellurium–selenium (BTS) alloy as the write layer sandwiched between thin, protective films of reactively sputtered carbon. The composition and thickness of the BTS layer were confirmed by Rutherford Backscattering (RBS) and atomic force microscopy (AFM), respectively. The C/BTS/C stack on Mylar was written to/marked by 532 nm laser pulses. Under the same conditions, control Mylar films without the optical stack were unaffected. Marks, which showed craters/movement of the write material, were characterized by optical microscopy and AFM. The threshold laser powers for making marks on C/BTS/C stacks with different thicknesses were explored. Higher quality marks were made with a 60× objective compared to a 40× objective in our marking apparatus. Finally, the laser writing process was simulated with COMSOL.

  4. Research and Development on Titanium Alloys

    Science.gov (United States)

    1949-08-31

    61 No. 733 LWE: ec/mk/ma September 14, 1949 13ATTK- LLE MESMORIAL INSTITUTE DEPARTMENT OF THE AIR FORCE HEADOUARTERS AERONAUTICAL SYSTEMS CENTER (AFMC...period reported, titanium binary alloys of germanium and nickel vere studied, as venl as tltanium-molybdenum and titanium- manganese ternary alloys. Carbon...September 18, 1949, titanium binary alloys of germanium and nickel were studied. Also investigated were titanium-molybdenum and titanium-manganese ternary

  5. Ternary chalcopyrite semiconductors

    CERN Document Server

    Shay, J L; Pamplin, B R

    2013-01-01

    Ternary Chalcopyrite Semiconductors: Growth, Electronic Properties, and Applications covers the developments of work in the I-III-VI2 and II-IV-V2 ternary chalcopyrite compounds. This book is composed of eight chapters that focus on the crystal growth, characterization, and applications of these compounds to optical communications systems. After briefly dealing with the status of ternary chalcopyrite compounds, this book goes on describing the crystal growth of II-IV-V2 and I-III-VI2 single crystals. Chapters 3 and 4 examine the energy band structure of these semiconductor compounds, illustrat

  6. Effect of a novel load-bearing trabecular Nitinol scaffold on rabbit radius bone regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Gotman, Irena, E-mail: gotman@technion.ac.il; Gutmanas, Elazar Y., E-mail: gutmanas@technion.ac.il [Department of Materials Science and Engineering, Techion-Israel Institute of Technology, Haifa, 32000 Israel (Israel); National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Zaretzky, Asaph [The Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, 31096 Israel (Israel); Psakhie, Sergey G. [National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation)

    2015-10-27

    The research aim was to evaluate the bone regeneration capability of novel load-bearing NiTi alloy (Nitinol) scaffolds in a critical-size defect (CSD) model. High strength “trabecular Nitinol” scaffolds were prepared by PIRAC (Powder Immersion Reaction Assisted Coating) annealing of the highly porous Ni foam in Ti powder at 900°C. This was followed by PIRAC nitriding to mitigate the release of potentially toxic Ni ions. Scaffolds phase composition and microstructure were characterized by X-ray diffraction and scanning electron microscopy (SEM/EDS), and their mechanical properties were tested in compression. New Zealand white rabbits received bone defect in right radius and were divided in four groups randomly. In the control group, nothing was placed in the defect. In other groups, NiTi scaffolds were implanted in the defect: (i) as produced, (ii) loaded with bone marrow aspirate (BMA), and (iii) biomimetically CaP-coated. The animals were sacrificed after 12 weeks. The forelimbs with scaffolds were resected, fixed, sectioned and examined in SEM. New bone formation inside the scaffold was studied by EDS analysis and by the processing of backscattered electron images. Bone ingrowth into the scaffold was observed in all implant groups, mostly next to the ulna. New bone formation was strongly enhanced by BMA loading and biomimeatic CaP coating, the bone penetrating as much as 1–1.5 mm into the scaffold. The results of this preliminary study demonstrate that the newly developed high strength trabecular Nitinol scaffolds can be successfully used for bone regeneration in critical size defects.

  7. CHARACTERIZING SURFACE LAYERS IN NITINOL USING X-RAY PHOTOELECTRON SPECTROSCOPY

    Energy Technology Data Exchange (ETDEWEB)

    Christopfel, R.; Mehta, A.

    2008-01-01

    Nitinol is a shape memory alloy whose properties allow for large reversible deformations and a return to its original geometry. This nickel-titanium (NiTi) alloy has become a material used widely in the biomedical fi eld as a stent to open up collapsed arteries. Both ambient and biological conditions cause surface oxidation in these devices which in turn change its biocompatibility. The thickness of oxidized layers can cause fractures in the material if too large and can allow for penetration if too thin. Depending on the type and abundance of the chemical species on or near the surface, highly toxic metal ions can leak into the body causing cell damage or even cell death. Thus, biocompatibility of such devices is crucial. By using highly surface sensitive x-ray photoelectron spectroscopy to probe the surface of these structures, it is possible to decipher both layer composition and layer thickness. Two samples, both of which were mechanically polished, were investigated. Of the two samples, one was then exposed to a phosphate buffered saline (PBS) solution to mimic the chemical properties of blood, while the other remained unexposed. Although both samples were found to have oxide layers of appropriate thickness (on the order of a few nm), it was found that the sample exposed to the saline solution had a slightly thicker oxide layer and more signifi cantly, a phosphate layer very near the surface suggesting toxic metal components are well contained within the sample. These are considerable indications of a biocompatible device.

  8. Addressing Machining Issues for the Intermetallic Compound 60-NITINOL

    Science.gov (United States)

    Stanford, Malcolm K.; Wozniak, Walter A.; McCue, Terry R.

    2012-01-01

    60-NITINOL (60 wt.% Ni - 40 wt.% Ti) is being studied as a material for advanced aerospace components. Frequent wire breakage during electrical-discharge machining of this material was investigated. The studied material was fabricated from hot isostatically pressed 60-NITINOL powder obtained through a commercial source. Bulk chemical analysis of the material showed that the composition was nominal but had relatively high levels of certain impurities, including Al and O. It was later determined that Al2O3 particles had contaminated the material during the hot isostatic pressing procedure and that these particles were the most likely cause of the wire breakage. The results of this investigation highlight the importance of material cleanliness to its further implementation.

  9. Contributions to Design of Actuators functioning with Nitinol Active Springs

    Directory of Open Access Journals (Sweden)

    Daniel Amariei

    2015-07-01

    Full Text Available The paper presents the research results achieved in order to perform a comparison regarding the influence of natural and forced cooling process applied to the Nitinol active springs inside a linear motion actuator. SMAs offer attractive potentials such as reversible strains of several percent, generation of high recovery stresses and high power / weight ratios. The actuator behavior was simulated first with SolidWorks and experimentally tested for results validation.

  10. Treatment of otosclerosis with a superelastic nitinol piston: first results.

    Science.gov (United States)

    Bast, F; Weikert, S; Schrom, T

    2011-04-01

    Stapedotomy with implantation of an alloplastic prosthesis is a well-established therapy for the treatment of otosclerosis. Since the middle of 2008, a new Nitinol prosthesis with memory function and superelastic properties has been available which is expected to make fixation on the long process of the incus much easier. The advantage of this prosthesis is that heat-induced wire crimping is no longer necessary and damage to the incus caused by heat is avoided. Since May 2008, laser-assisted stapedotomy with implantation of a Nitinol prosthesis was performed in 21 patients suffering from otosclerosis. The prostheses used for all patients had a size of 4.5 mm × 0.4 mm. The patient collective consisted of 14 women and 7 men with a mean age of 53.4 years. Pre- and postoperatively, an ENT examination was carried out followed by an audiological evaluation of the hearing result. In addition, the properties of the prosthesis ("proper fitt", "handling", and "overall rating") were evaluated intraoperatively by means of a test protocol. The Nitinol prosthesis was implanted successfully in all 21 patients. The mean air-bone gap for the frequencies from 0.5 to 4 kHz was 9.83 dB postoperatively. Intraoperatively, the fit of the prosthesis was rated as "good to very good", the handling as "good" and the overall rating of the system was "good to very good". Our patient collective showed good postoperative hearing results. Due to simple intraoperative handling, especially placing the Nitinol prosthesis in position, the critical work step of crimping is no longer necessary.

  11. Designing and simulating a nitinol-based micro ejector

    Directory of Open Access Journals (Sweden)

    Yesid Mora Sierra

    2012-01-01

    Full Text Available This paper describes pico-droplet ejector design and simulation. The actuation system was based on two interconnected nitinol membranes’ shape memory effect. Ejected volume was 12pL and it operated at 30°C to 64°C. Ejecting excitation voltage was 12V and the ejecting energy required by actuator operation was 26µJ per drop. These pico-liter ejectors could have applications in making, lubricating and cooling integrated circuits.

  12. Malignant duodenal obstructions: palliative treatment with covered expandable nitinol stent

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Chul; Jung, Gyoo Sik; Lee, Sang Hee; Kim, Sung Min; Oh, Kyung Seung; Huh, Jin Do; Cho, Young Duk [College of Medicine, Kosin Univ, Pusan (Korea, Republic of); Song, Ho Young [College of Medicine, Ulsan Univ., Seoul (Korea, Republic of)

    2002-04-01

    To evaluate the feasibility and clinical effectiveness of using a polyurethane-covered expandable nitinol stent in the palliative treatment of malignant duodenal obstruction. Under fluoroscopic guidance, a polyurethane-covered expandable nitinol stent was placed in 12 consecutive patients with malignant duodenal obstructions. All presented with severe nausea and recurrent vomiting. The underlying causes of obstruction were duodenal carcinoma (n=4), pancreatic carcinoma (n=4), gall bladder carcinoma (n=2), distal CBD carcinoma (n=1), and uterine cervical carcinoma (n=1). The sites of obstruction were part I (n=1), part II (n=8), and III (n=3). Due to pre-existing jaundice, eight patients with part II obstructions underwent biliary decompression prior to stent placement. An introducer sheath with a 6-mm outer diameter and stents 16 mm in diameter were employed, and to place the stent, and after-loading technique was used. Stent placement was technically successful in ten patients, and no procedural complications occuured. In one of two patients in whom there was technical failure, and in whom the obstructions were located in part III, the stent was placed transgastrically. Stent migration occurred in one patient four days after the procedure, and treatment involved the palcement of a second, uncovered, nitinol stent. After stent placement, symptoms improved in all patients. During follow-up, obstructive symptoms due to stent stenosis (n=1), colonic obstruction (n=1), and multiple small bowel obstruction (n=1) recurred in three patients. Two of these were treated by placing additional stents in the duodenum and colon, respectively. One of the eight patients in whom a stent was placed in the second portion of the duodenum developed jaundice. The patients died a mean 14 (median, 9) weeks after stent placement. The placement of a polyurethane-covered expandable nitinol stent seems to be technically feasible, safe and effective for the palliative treatment of malignant

  13. Designing and simulating a nitinol-based micro ejector

    Directory of Open Access Journals (Sweden)

    Yesid Mora Sierra

    2012-04-01

    Full Text Available This paper describes pico-droplet ejector design and simulation. The actuation system was based on two interconnected nitinol membranes’ shape memory effect. Ejected volume was 12pL and it operated at 30°C to 64°C. Ejecting excitation voltage was 12V and the ejecting energy required by actuator operation was 26µJ per drop. These pico-liter ejectors could have applications in making, lubricating and cooling integrated circuits.

  14. Compliant articulation structure using superelastic NiTiNOL

    Science.gov (United States)

    Liu, Jiening; Hall, Benjamin; Frecker, Mary; Reutzel, Edward W.

    2013-09-01

    A device that can provide articulation to surgical tool tips is needed in natural orifice transluminal endoscopy surgery (NOTES). In this paper, we propose a compliant articulation structure that uses superelastic NiTiNOL to achieve a large deflection angle and force in a compact size. Six geometric parameters are used to define this structure, and constraints based on the fabrication process are imposed. Using finite element analysis, a family of designs is evaluated in terms of the free deflection angle and blocked force. The same family of designs is evaluated for both NiTiNOL and stainless steel. It can be seen that significant benefits are observed when using NiTiNOL compared to 316 stainless steel; a maximum free deflection angle of 64.8° and maximum blocked force of 24.7 N are predicted. The structures are designed to avoid stress concentrations, and design guidelines are recommended. The meso-scale articulation structure is fabricated using both a Coherent Avia Q-switched, 355 nm laser and a Myachi Unitek 200 W single mode pulsed fiber laser with active water cooling. Select fabricated structures are then tested to validate the finite element models.

  15. A retrievable nitinol endobronchial stent : an experimental study in dog

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Sang Jin; Park, Sang Soo; Yoon, Hyun Ki; Sung, Kyu Bo; Song, Ho Young [Asan Medical Center, Ulsan Univ. College of Medicine, Seoul (Korea, Republic of); Kang, Sung Gwon [Inha Univ. College of Medicine, Inchon (Korea, Republic of)

    1999-06-01

    The purpose of this study was to evaluate the safety and the retrievability of a new covered retrievable nitinol tracheobronchial stent. Stents were knitted from 0.2mm nitinol wire, covered with polyurethane, and were 20-22mm in diameter and 2cm in length. Under fluoroscopic guidance, a stent was placed in the normal right bronchus intermedius of ten dogs. Using a retrieval hook, stent retrieval was attempted after 1 month(N=5) or 2 months(N=5). After removal, the dogs were sacrificed and their their tracheobronchial trees were examined grossly and histologically. Eleven stents were successfully placed in ten dogs. Migration and expectoration occurred in four of ten stents in nine dogs(40%). Five stents were successfully removed from six dogs(83%). Without significant difference between the two groups, mild to moderate mucosal hyperplasia was noted at the sites of stents as well as above and below them. On microscopy, three of five dogs showed pneumonia in the right middle lobes, but none of the stents was covered with epithelium. Temporary placement of a covered expandable nitinol stent in the tracheobronchial tree is feasible, but to establish its efficacy, further experimental studies are needed.

  16. Fracture of Polymer-Coated Nitinol During Gamma Sterilization

    Science.gov (United States)

    Norwich, Dennis W.

    2012-12-01

    After gamma sterilization of a packaged medical device, fractures were discovered in the superelastic nitinol wire used as part of the assembly. The nitinol wire was encased in fluorinated ethylene propylene (FEP) shrink tube. The only fractures occurred where the encased wire was held under strain during gamma sterilization. A study was conducted to determine the susceptibility of nitinol to this type of failure. The variables studied included wire diameter, wire surface finish, wire oxide layer, quantity of wires encased, type of tubing, and strain level during gamma sterilization. The greatest susceptibility to fracture occurred to single wire samples with a light oxide layer held under high strain in FEP shrink tube. Gamma sterilization experiments were conducted to isolate and confirm this failure mechanism. Scanning electron microscopy was used to analyze the fractured samples. Chemical analysis was performed in an attempt to detect trace elements to determine the root cause of the failures. Stress corrosion cracking caused by the liberation of fluorine due to the degradation of the polymer during gamma sterilization is suspected.

  17. Martensitic transformations in nanostructured nitinol: Finite element modeling of grain size and distribution effects

    DEFF Research Database (Denmark)

    Liu, Hong-Sheng; Mishnaevsky, Leon

    2013-01-01

    transformation are totally suppressed. Graded and localized distributions of grain sizes of nitinol were compared with nitinol samples with homogeneous grain size distribution. In the materials with localized region of small grains, it was observed that the martensite rich regions form first on the border......A computational model of martensitic phase transformation in nanostructured nitinol is developed which takes into account the grain size effect. On the basis of the theoretical analysis of the thermodynamic transformation criterion and the energy barrier for phase transformation......, it was demonstrated that the energy barrier for martensitic phase transformation in nanocrystalline nitinol increase drastically with decreasing the grain size. Finite element simulations of phase transformations and structure evolution in nanocrystalline nitinol under mechanical (tensile) loading are carried out...

  18. The intrinsically high pitting corrosion resistance of mechanically polished nitinol in simulated physiological solutions.

    Science.gov (United States)

    Bai, Zhijun; Rotermund, Harm H

    2011-10-01

    Nitinol wires have been widely used in many biomedical applications, such as cardiovascular stent due to their superelasticity and shape memory effect. However, their corrosion properties and the related biocompatibility are not well understood, and the reported results are controversial. In this study, we evaluate the pitting corrosion property of nitinol, titanium, nickel, and 316L stainless steel (316LSS) wires with different surface roughnesses in a saline solution at 37 °C. The cyclic potentiodynamic polarization results show that mechanically polished nitinol and Ti wires are highly resistant to pitting corrosion, while Ni and 316LSS wires are susceptible to pitting corrosion. Electrochemical impedance spectroscopy is used to study the interface of oxide film/solution and all mechanically polished nitinol wires are covered by 2-3 nm thick films formed under open circuit potential. Furthermore, the electronic structures and semiconducting properties of passive films on nitinol, Ti and Ni wires are studied by Mott-Schottky analysis. Passive films formed on nitinol and Ti exhibit n-type semiconducting characteristics, whereas films on Ni show p-type semiconducting characteristics. Scanning Kelvin Microscopy is used to measure the surface potential difference between common inclusions from the nitinol matrix and the results indicate that the inclusions are more electrochemically noble than the nitinol matrix. Band energy theory is used to model the electrochemical interface between the passive films of nitinol and the solution under different applied potential conditions. A mechanism for the strong pitting corrosion resistance of nitinol in saline solution is proposed. Copyright © 2011 Wiley Periodicals, Inc.

  19. A New Coated Nitinol Occluder for Transcatheter Closure of Ventricular Septal Defects in a Canine Model

    Directory of Open Access Journals (Sweden)

    Yong Zhou

    2013-01-01

    Full Text Available Aims. This study evaluated feasibility and safety of implanting the polyester-coated nitinol ventricular septal defect occluder (pcVSDO in the canine model. Methods and Results. VSD models were successfully established by transseptal ventricular septal puncture via the right jugular vein in 15 out of 18 canines. Two types of VSDOs were implanted, either with pcVSDOs (n=8 as the new type occluder group or with the commercial ventricular septal defect occluders (VSDOs, n=7, Shanghai Sharp Memory Alloy Co. Ltd. as the control group. Sheath size was 10 French (10 Fr in two groups. Then the general state of the canines was observed after implantation. ECG and TTE were performed, respectively, at 7, 30, 90 days of follow-up. The canines were sacrificed at these time points for pathological and scanning electron microscopy examination. The devices were successfully implanted in all 15 canines and were retrievable and repositionable. There was no thrombus formation on the device or occurrence of complete heart block. The pcVSDO surface implanted at day 7 was already covered with neotissue by gross examination, and it completed endothelialization at day 30, while the commercial VSDO was covered with the neotissue in 30th day and the complete endothelialization in 90th day. Conclusion. The study shows that pcVSDO is feasible and safe to close canine VSD model and has good biocompatibility and shorter time of endothelialization.

  20. PEEK (polyether-ether-ketone)-coated nitinol wire: Film stability for biocompatibility applications

    Science.gov (United States)

    Sheiko, Nataliia; Kékicheff, Patrick; Marie, Pascal; Schmutz, Marc; Jacomine, Leandro; Perrin-Schmitt, Fabienne

    2016-12-01

    High quality biocompatible poly-ether-ether-ketone (PEEK) coatings were produced on NiTi shape memory alloy wires using dipping deposition from colloidal aqueous PEEK dispersions after substrate surface treatment. The surface morphology and microstructure were investigated by Scanning Electron Microscopy at every step of the process from the as-received Nitinol substrate to the ultimate PEEK-coated NiTi wire. Nanoscratch tests were carried out to access the adhesive behavior of the polymer coated film to the NiTi. The results indicate that the optimum process conditions in cleaning, chemical etching, and electropolishing the NiTi, were the most important and determining parameters to be achieved. Thus, high quality PEEK coatings were obtained on NiTi wires, straight or curved (even with a U-shape) with a homogeneous microstructure along the wire length and a uniform thickness of 12 μm without any development of cracks or the presence of large voids. The biocompatibility of the PEEK coating film was checked in fibrobast cultured cells. The coating remains stable in biological environment with negligible Ni ion release, no cytotoxicity, and no delamination observed with time.

  1. Fatigue Behavior Characterization of Nitinol for Peripheral Stents

    Science.gov (United States)

    Petrini, Lorenza; Wu, Wei; Dordoni, Elena; Meoli, Alessio; Migliavacca, Francesco; Pennati, Giancarlo

    2012-03-01

    Nitinol stents are nowadays widely used for the treatment of occlusions in peripheral arteries. However, the expansion of this indication has also highlighted some complications. In particular, the patient daily activities expose the peripheral arteries to large and cyclic deformations which may cause long-term failure of the device and consequently re-occlusion of the artery. Accordingly, the assessment of the stent fatigue rupture is of primary importance to assure the effectiveness of stenting procedure. However the fatigue behavior characterization of Nitinol for peripheral stent is a quite difficult problem because of the complexity of the in vivo solicitations the stent is subjected to and the strong nonlinearity in the material response. In this paper we approached the problem in two steps: (i) in the first step the study of the stent solicitations under realistic (physiological) conditions was performed through the use of numerical simulations which allowed sophisticated patient-specific models of the stenting procedure; (ii) in the second step, the previous results were used for the design of an experimental campaign and the following execution of the tests for the material mechanical characterization and fatigue life study. The tests were performed on Nitinol specimens derived from the same tubes used for producing a commercial peripheral stent and created following the same procedure employed for the device. As a consequence of the small dimension of the specimens, a preliminary design of the experimental test set-up was also required. The obtained results allowed a sufficiently accurate characterization of the stent material fatigue behavior in the range of interest.

  2. New Theoretical Technique for Alloy Design

    Science.gov (United States)

    Ferrante, John

    2005-01-01

    During the last 2 years, there has been a breakthrough in alloy design at the NASA Lewis Research Center. A new semi-empirical theoretical technique for alloys, the BFS Theory (Bozzolo, Ferrante, and Smith), has been used to design alloys on a computer. BFS was used, along with Monte Carlo techniques, to predict the phases of ternary alloys of NiAl with Ti or Cr additions. High concentrations of each additive were used to demonstrate the resulting structures.

  3. Characterization the microstructure of pulsed Nd:YAG welding method in low frequencies; correlation with tensile and fracture behavior in laser-welded nitinol joints

    Science.gov (United States)

    Shojaei Zoeram, Ali; Rahmani, Aida; Asghar Akbari Mousavi, Seyed Ali

    2017-05-01

    The precise controllability of heat input in pulsed Nd:YAG welding method provided by two additional parameters, frequency and pulse duration, has made this method very promising for welding of alloys sensitive to heat input. The poor weldability of Ti-rich nitinol as a result of the formation of Ti2Ni IMC has deprived us of the unique properties of this alloy. In this study, to intensify solidification rate during welding of Ti-rich nitinol, pulsed Nd:YAG laser beam in low frequency was employed in addition to the employment of a copper substrate. Specific microstructure produced in this condition was characterized and the effects of this microstructure on tensile and fracture behavior of samples welded by two different procedures, full penetration and double-sided method with halved penetration depth for each side were investigated. The investigations revealed although the combination of low frequencies, the use of a high thermal conductor substrate and double-sided method eliminated intergranular fracture and increased tensile strength, the particular microstructure, built in the pulsed welding method in low frequencies, results to the formation of the longitudinal cracks during the first stages of tensile test at weld centerline. This degrades tensile strength of welded samples compared to base metal. The results showed samples welded in double-sided method performed much better than samples welded in full penetration mode.

  4. Corrosion resistance improvement of nitinol by anodisation in the presence of molybdate ions

    Energy Technology Data Exchange (ETDEWEB)

    Saugo, M. [Instituto de Ingeniería Electroquímica y Corrosión (INIEC), Departamento de Ingeniería Química, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahía Blanca (Argentina); Flamini, D.O., E-mail: dflamini@uns.edu.ar [Instituto de Ingeniería Electroquímica y Corrosión (INIEC), Departamento de Ingeniería Química, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahía Blanca (Argentina); Zampieri, G. [Centro Atómico Bariloche, Comisión Nacional de Energía Atómica, Av. Bustillo 9500, 8400 San Carlos de Bariloche (Argentina); Instituto Balseiro, Universidad Nacional de Cuyo, Av. Bustillo 9500, 8400 San Carlos de Bariloche (Argentina); Saidman, S.B. [Instituto de Ingeniería Electroquímica y Corrosión (INIEC), Departamento de Ingeniería Química, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahía Blanca (Argentina)

    2017-04-01

    The corrosion behaviour of Nitinol (NiTi) alloy was studied in Ringer solution. In order to improve its corrosion resistance, protective films were formed on the NiTi surface by means of anodisation under potentiostatic or galvanostatic control in the presence of the corrosion inhibitor molybdate in alkaline and acidic solutions. The anodisation process reduces considerably the Ni content and increases the Ti content in the oxide film, indicating that the Ti/Ni stoichiometry in the outermost surface is much higher than in pure NiTi. The titanium enrichment on the outermost surface as TiO{sub 2} enhanced its anticorrosion performance, as was suggested by the decrease in the amount of Ni and Ti released in Ringer solution under open circuit potential (OCP) condition and under potentials where the bare substrate suffers pitting attack. The best anodised film in terms of corrosion protection was obtained under potentiostatic condition in alkaline solution. The presence of oxidised molybdenum species in the oxide potentiostatically grown in alkaline solution, generates a corrosion protective film with a smoother and denser surface than other oxides formed in acidic solutions, without any defects like micro-cracks or pores. - Highlights: • NiTi alloy was anodised applying a low voltage in the presence of a MoO{sub 4}{sup −2} solution. • The formed oxides provided good corrosion protection to the substrate. • The presence of Mo in the oxide film was confirmed by different techniques. • The increase of the Ti/Ni ratio in the oxidised sample was key to protection.

  5. Effects of Crimping on Mechanical Performance of Nitinol Stent Designed for Femoral Artery: Finite Element Analysis

    Science.gov (United States)

    Nematzadeh, F.; Sadrnezhaad, S. K.

    2013-11-01

    Nitinol stents are used to minimize improper dynamic behavior, low twistability, and inadequate radial mechanical strength of femoral artery stents. In this study, finite element method is used to investigate the effect of crimping and Austenite finish temperature ( A f) of Nitinol on mechanical performance of Z-shaped open-cell femoral stent under crimping conditions. Results show that low A f Nitinol has better mechanical and clinical performance due to small chronic outward force, large radial resistive force, and appropriate superelastic behavior.

  6. Thermodynamics of liquid aluminium-copper-silicon alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kanibolotsky, D.S.; Bieloborodova, O.A.; Stukalo, V.A.; Kotova, N.V.; Lisnyak, V.V

    2004-03-23

    In this paper, thermodynamic properties of liquid Al-Cu-Si alloys were studied by electromotive force method with liquid electrolyte at 920-1250 K and by high-temperature isoperibolic calorimetry at 1750{+-}5 K. The integral enthalpy of mixing in ternary Al-Cu-Si melts was estimated by Bonnier model for definition of boundary binary systems contribution to ternary alloys thermodynamics. The satisfactory agreement between experimental and estimated data demonstrates that thermodynamic properties of ternary liquid alloys are mainly defined by thermodynamic behaviour of boundary binary systems. Analysis of concentration and thermal dependencies of thermodynamic functions of mixing in liquid Al-Cu-Si alloys has been performed. It has been established that increasing of temperature results in decreasing of the integral enthalpy of mixing. This fact is probably associated with contribution of silicon clusters into ternary alloys thermodynamics.

  7. Improved Damage Resistant Composite Materials Incorporating Shape Memory Alloys

    Science.gov (United States)

    Paine, Jeffrey S. N.; Rogers, Craig A.

    1996-01-01

    Metallic shape memory alloys (SMA) such as nitinol have unique shape recovery behavior and mechanical properties associated with a material phase change that have been used in a variety of sensing and actuation applications. Recent studies have shown that integrating nitinol-SMA actuators into composite materials increases the composite material's functionality. Hybrid composites of conventional graphite/epoxy or glass/epoxy and nitinol-SMA elements can perform functions in applications where monolithic composites perform inadequately. One such application is the use of hybrid composites to function both in load bearing and armor capacities. While monolithic composites with high strength-to-weight ratios function efficiently as loadbearing structures, because of their brittle nature, impact loading can cause significant catastrophic damage. Initial composite failure modes such as delamination and matrix cracking dissipate some impact energy, but when stress exceeds the composite's ultimate strength, fiber fracture and material perforation become dominant. One of the few methods that has been developed to reduce material perforation is hybridizing polymer matrix composites with tough kevlar or high modulus polyethynylene plies. The tough fibers increase the impact resistance and the stiffer and stronger graphite fibers carry the majority of the load. Similarly, by adding nitinol-SMA elements that absorb impact energy through the stress-induced martensitic phase transformation, the composites' impact perforation resistance can be greatly enhanced. The results of drop-weight and high velocity gas-gun impact testing of various composite materials will be presented. The results demonstrate that hybridizing composites with nitinol-SMA elements significantly increases perforation resistance compared to other traditional toughening elements. Inspection of the composite specimens at various stages of perforation by optical microscope illustrates the mechanisms by which

  8. Nanostructured Platinum Alloys for Use as Catalyst Materials

    Science.gov (United States)

    Hays, Charles C. (Inventor); Narayan, Sri R. (Inventor)

    2015-01-01

    A series of binary and ternary Pt-alloys, that promote the important reactions for catalysis at an alloy surface; oxygen reduction, hydrogen oxidation, and hydrogen and oxygen evolution. The first two of these reactions are essential when applying the alloy for use in a PEMFC.

  9. Effects of Cyclic Loading on the Uniaxial Behavior of Nitinol

    Science.gov (United States)

    Schlun, M.; Zipse, A.; Dreher, G.; Rebelo, N.

    2011-07-01

    The widespread development and use of implants made from NiTi is accompanied by the publication of many NiTi material characterization studies. These publications have increased significantly the knowledge about the mechanical properties of NiTi. However, this knowledge also increased the complexity of the numerical simulation of NiTi implants or devices. This study is focused on the uniaxial behavior of NiTi tubing due to cyclic loading and had the goal to deliver both precise and application-oriented results. Single aspects of this study have already been published (Wagner in Ein Beitrag zur strukturellen und funktionalen Ermüdung von Drähten und Federn aus NiTi-Formgedaechtnislegierungen, Ph.D. Thesis, 2005; Eucken and Duerig in Acta Metall 37:2245-2252, 1989; Yawny et al. in Z Metallkd 96:608-618, 2005); however, there is no publication known that shows all the single effects combined in a "duty cycle case." It was of particular importance to summarize the main effects of pre-strain and subsequent small or large strain amplitudes on the material properties. The phenomena observed were captured in an extended Abaqus® Nitinol material model, presented by Rebelo et al. (A Material Model for the Cyclic Behavior of Nitinol, SMST Extended Abstracts 2010). The cyclic tensile tests were performed using a video extensometer to obtain accurate strain measurement on small electro-polished dog-bone specimen that were incorporated into a stent framework so that standard manufacturing methods could be used for the fabrication. This study indicates that a prestrain beyond 6% strain alters the transformation plateaus and if the cyclic displacement amplitude is large enough, additional permanent deformations are observed, the lower plateau and most notably the upper plateau change. The changes to the upper plateau are very interesting in the sense that an additional stress plateau develops: its "start stress" is lowered thereby creating a new plateau up to the highest level

  10. Nitinol-teflon stapes prosthesis improves low-frequency hearing results after stapedotomy.

    Science.gov (United States)

    Mangham, Charles A

    2010-09-01

    To determine if nitinol-Teflon shape-memory stapes prostheses offer a hearing result advantage compared with platinum-Teflon pistons that must be manually crimped. Retrospective chart review. One hundred eighty-eight consecutive ears with either a platinum or a nitinol piston and primary stapes surgery between 1998 and 2009. Subspecialty private practice. One hundred forty-four ears received a platinum 0.6-mm-diameter piston, and 44 ears received a nitinol 0.6-mm-diameter piston. American Academy of Otolaryngology-Head and Neck Surgery guidelines, including 4-frequency pure-tone average air-bone (AB) gap, and success (gap nitinol, 92%; p = not significant). The nitinol group had significantly smaller mean AB gaps in the lower frequencies (at 250 Hz, 9.3 versus 15.4 dB and at 500 Hz, 1.9 versus 5.0 dB; p's < 0.01), but not at 1, 2 or 4 kHz. The highly malleable platinum loop was adaptable to various incus diameters and was easy to crimp. The 360-degree circumferential version of the nitinol prosthesis may adapt to various incus diameters better than the original version (minimum heat-crimped diameter, 0.70 versus 0.76 mm). In some cases, both nitinol versions were difficult to crimp using only a laser, and a manual crimp was also required. The nitinol stapes prostheses failed to live up to claims of consistent ease of crimping; however, the significantly better low-frequency hearing results justify an effort to make the devices more user friendly.

  11. A torsional artificial muscle from twisted nitinol microwire

    Science.gov (United States)

    Mirvakili, Seyed M.; Hunter, Ian W.

    2017-04-01

    Nitinol microwires of 25 μm in diameter can have tensile actuation of up to 4.5% in less than 100 ms. A work density of up to 480 MPa can be achieved from these microwires. In the present work, we are showing that by twisting the microwires in form of closed-loop two-ply yarn we can create a torsional actuator. We achieved a revisable torsional stroke of 46°/mm with peak rotational speed of up to 10,000 rpm. We measured a gravimetric torque of up to 28.5 N•m/kg which is higher than the 3 - 6 N•m/kg for direct-drive commercial electric motors. These remarkable performance results are comparable to those of guest-infiltrated carbon nanotube twisted yarns.

  12. Charpy Impact Energy and Microindentation Hardness of 60-NITINOL

    Science.gov (United States)

    Stanford, Malcolm K.

    2012-01-01

    60-NITINOL (60 wt.% Ni 40 wt.% Ti) is being studied as a material for advanced aerospace components. The Charpy impact energy and microindentation hardness has been studied for this material, fabricated by vacuum induction skull melting (casting) and by hot isostatic pressing. Test specimens were prepared in various hardened and annealed heat treatment conditions. The average impact energy ranged from 0.33 to 0.49J for the hardened specimens while the annealed specimens had impact energies ranging from 0.89 to 1.18J. The average hardness values of the hardened specimens ranged from 590 to 676 HV while that of the annealed specimens ranged from 298 to 366 HV, suggesting an inverse relationship between impact energy and hardness. These results are expected to provide guidance in the selection of heat treatment processes for the design of mechanical components.

  13. Approximately Ternary Homomorphisms on C*-Ternary Algebras

    Directory of Open Access Journals (Sweden)

    Eon Wha Shim

    2013-01-01

    functional equation: fx2-x1/3+fx1-3x3/3+f3x1+3x3-x2/3=fx1, by the direct method. Under the conditions in the main theorems, we can show that the related mappings must be zero. In this paper, we correct the conditions and prove the corrected theorems. Furthermore, we prove the Hyers-Ulam stability and the superstability of C*-ternary homomorphisms and C*-ternary derivations on C*-ternary algebras by using a fixed point approach.

  14. Nitinol Embolic Protection Filters: Design Investigation by Finite Element Analysis

    Science.gov (United States)

    Conti, Michele; de Beule, Matthieu; Mortier, Peter; van Loo, Denis; Verdonck, Pascal; Vermassen, Frank; Segers, Patrick; Auricchio, Ferdinando; Verhegghe, Benedict

    2009-08-01

    The widespread acceptance of carotid artery stenting (CAS) to treat carotid artery stenosis and its effectiveness compared with surgical counterpart, carotid endarterectomy (CEA), is still a matter of debate. Transient or permanent neurological deficits may develop in patients undergoing CAS due to distal embolization or hemodynamic changes. Design, development, and usage of embolic protection devices (EPDs), such as embolic protection filters, appear to have a significant impact on the success of CAS. Unfortunately, some drawbacks, such as filtering failure, inability to cross tortuous high-grade stenoses, malpositioning and vessel injury, still remain and require design improvement. Currently, many different designs of such devices are available on the rapidly growing dedicated market. In spite of such a growing commercial interest, there is a significant need for design tools as well as for careful engineering investigations and design analyses of such nitinol devices. The present study aims to investigate the embolic protection filter design by finite element analysis. We first developed a parametrical computer-aided design model of an embolic filter based on micro-CT scans of the Angioguard™ XP (Cordis Endovascular, FL) EPD by means of the open source pyFormex software. Subsequently, we used the finite element method to simulate the deployment of the nitinol filter as it exits the delivery sheath. Comparison of the simulations with micro-CT images of the real device exiting the catheter showed excellent correspondence with our simulations. Finally, we evaluated circumferential basket-vessel wall apposition of a 4 mm size filter in a straight vessel of different sizes and shape. We conclude that the proposed methodology offers a useful tool to evaluate and to compare current or new designs of EPDs. Further simulations will investigate vessel wall apposition in a realistic tortuous anatomy.

  15. PEEK (polyether-ether-ketone)-coated nitinol wire: Film stability for biocompatibility applications

    Energy Technology Data Exchange (ETDEWEB)

    Sheiko, Nataliia [Institut Charles Sadron, C.N.R.S. UPR 22, Université de Strasbourg, 23 rue du Loess, BP 84047, 67034 Strasbourg Cedex 2 (France); Kékicheff, Patrick, E-mail: patrick.kekicheff@ics-cnrs.unistra.fr [Institut Charles Sadron, C.N.R.S. UPR 22, Université de Strasbourg, 23 rue du Loess, BP 84047, 67034 Strasbourg Cedex 2 (France); Marie, Pascal; Schmutz, Marc; Jacomine, Leandro [Institut Charles Sadron, C.N.R.S. UPR 22, Université de Strasbourg, 23 rue du Loess, BP 84047, 67034 Strasbourg Cedex 2 (France); Perrin-Schmitt, Fabienne [Faculté de Médecine, INSERM, UMR-S 1121, “Biomaterials and Bioengineering”, Université de Strasbourg, 11 rue Humann, 67085 Strasbourg Cedex (France)

    2016-12-15

    Highlights: • A thin (12 μm) homogeneous PEEK film without any defects or voids is deposited on NiTi wires. • The coating remains stable in biological environment with negligible Ni ion release and no cytotoxicity. • Large pressure (>2 GPa) can only disrupt the coating film as shown by nanoscratch tests. • Coated spring wires sustain mechanical stress in continuous cycles of axial compression/stretching for >7 million cycles. - Abstract: High quality biocompatible poly-ether-ether-ketone (PEEK) coatings were produced on NiTi shape memory alloy wires using dipping deposition from colloidal aqueous PEEK dispersions after substrate surface treatment. The surface morphology and microstructure were investigated by Scanning Electron Microscopy at every step of the process from the as-received Nitinol substrate to the ultimate PEEK-coated NiTi wire. Nanoscratch tests were carried out to access the adhesive behavior of the polymer coated film to the NiTi. The results indicate that the optimum process conditions in cleaning, chemical etching, and electropolishing the NiTi, were the most important and determining parameters to be achieved. Thus, high quality PEEK coatings were obtained on NiTi wires, straight or curved (even with a U-shape) with a homogeneous microstructure along the wire length and a uniform thickness of 12 μm without any development of cracks or the presence of large voids. The biocompatibility of the PEEK coating film was checked in fibrobast cultured cells. The coating remains stable in biological environment with negligible Ni ion release, no cytotoxicity, and no delamination observed with time.

  16. Theoretical investigations of Co{sub 2}Mn{sub 1-x}Cr{sub x}Sn and Co{sub 2}MnSn{sub 1-y}Si{sub y} pseudo-ternary alloys: First principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Charifi, Z., E-mail: charifizoulikha@gmail.com [Physics Department, Faculty of Science, University of M' sila, 28000 M' sila (Algeria); Hamad, B. [Physics Department, The University of Jordan, Amman 11942 (Jordan); Physics Department, University of Arkansas, 825 W. Dickson St., Fayetteville, AR 72701 (United States); Baaziz, H. [Physics Department, Faculty of Science, University of M' sila, 28000 M' sila (Algeria); Soyalp, F. [Yüzüncü Yıl University, Faculty of Education, Department of Physics, Van 65080 (Turkey)

    2015-11-01

    The electronic and magnetic properties of Co{sub 2}Mn{sub 1−x}Cr{sub x}Sn and Co{sub 2}MnSn{sub 1−y}Si{sub y} alloys are investigated using density functional theory (DFT) within a full-potential linearized augmented-plane-wave (FP-LAPW) method. Amongst the systems under investigation, Co{sub 2}MnSn{sub 1−y}Si{sub y} alloys show half metallicity with 100% spin polarization at the Fermi level, however Co{sub 2}Mn{sub 1−x}Cr{sub x}Sn are found to be pseudo-half metals with few minority states at the Fermi level and high spin polarization. The substitution of Si with Sn keeps the magnetic moment constant in Co{sub 2}MnSn{sub 1−y}Si{sub y} alloys, whereas the substitution of Mn with Cr decreases the magnetic moment and degrade the half-metallicity in Co{sub 2}Mn{sub 1−x}Cr{sub x}Sn alloys. The Curie temperature is calculated and it is found to be about 928 K for all Co{sub 2}MnSn{sub 1−y}Si{sub y} alloys, whereas it decreases linearly with x for Co{sub 2}Mn{sub 1−x}Cr{sub x}Sn alloys. The lattices constants, bulk modulii, energy gaps, polarization ratio and density of states are calculated and their variation versus x or y are discussed. - Highlights: • The band structure calculations show that Co{sub 2}MnSn{sub 1−y}Si{sub y} alloys are half-metallic ferromagnets. • The effect of substituting Sn by Si is a slight change in the position of the Fermi level and an increase in the band gap. • For Co{sub 2}Mn{sub 1−x}Cr{sub x}Sn alloys, the results suggest that there is a finite density of states in the minority-spin d band of manganese. • The Co{sub 2}Mn{sub 1−x}Cr{sub x}Sn compounds cannot be classified as half-metallic ferromagnets. • The substitution of Mn with Cr decreases the magnetic moment per formula unit from 5.0 to 4.0µ{sub B}.

  17. Iron binary and ternary coatings with molybdenum and tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Yar-Mukhamedova, Gulmira, E-mail: gulmira-alma-ata@mail.ru [Institute Experimental and Theoretical Physics Al-Farabi Kazakh National University, 050038, Al-Farabi av., 71, Almaty (Kazakhstan); Ved, Maryna; Sakhnenko, Nikolay; Karakurkchi, Anna; Yermolenko, Iryna [National Technical University “Kharkov Polytechnic Institute”, Kharkov (Ukraine)

    2016-10-15

    Highlights: • High quality coatings of double Fe-Mo and ternary Fe-Mo-W electrolytic alloys can be produced both in a dc and a pulsed mode. • Application of unipolar pulsed current allows receiving an increased content of the alloying components and their more uniform distribution over the surface. • It is established that Fe-Mo and Fe-Mo-W coatings have an amorphous structure and exhibit improved corrosion resistance and microhardness as compared with the steel substrate due to the inclusion molybdenum and tungsten. - Abstract: Electrodeposition of Fe-Mo-W and Fe-Mo layers from a citrate solution containing iron(III) on steel and iron substrates is compared. The utilization of iron(III) compounds significantly improved the electrolyte stability eliminating side anodic redox reactions. The influence of concentration ratios and electrodeposition mode on quality, chemical composition, and functional properties of the alloys is determined. It has been found that alloys deposited in pulse mode have more uniform surface morphology and chemical composition and contain less impurities. Improvement in physical and mechanical properties as well as corrosion resistance of Fe-Mo and Fe-Mo-W deposits when compared with main alloy forming metals is driven by alloying components chemical passivity as well as by alloys amorphous structure. Indicated deposits can be considered promising materials in surface hardening technologies and repair of worn out items.

  18. ZIRCONIUM-TITANIUM-BERYLLIUM BRAZING ALLOY

    Science.gov (United States)

    Gilliland, R.G.; Patriarca, P.; Slaughter, G.M.; Williams, L.C.

    1962-06-12

    A new and improved ternary alloy is described which is of particular utility in braze-bonding parts made of a refractory metal selected from Group IV, V, and VI of the periodic table and alloys containing said metal as a predominating alloying ingredient. The brazing alloy contains, by weight, 40 to 50 per cent zirconium, 40 to 50 per cent titanium, and the balance beryllium in amounts ranging from 1 to 20 per cent, said alloy having a melting point in the range 950 to 1400 deg C. (AEC)

  19. Fretting corrosion behavior of nitinol spinal rods in conjunction with titanium pedicle screws.

    Science.gov (United States)

    Lukina, Elena; Kollerov, Mikhail; Meswania, Jay; Khon, Alla; Panin, Pavel; Blunn, Gordon W

    2017-03-01

    Untypical corrosion damage including erosions combined with the build-up of titanium oxide as a corrosion product on the surface of explanted Nitinol spinal rods in the areas where it was in contact with titanium pedicle screw head is reported. It was suggested that Nitinol rods might have inferior fretting corrosion resistance compared with that made of titanium or CoCr. Fretting corrosion of Nitinol spinal rods with titanium (Ti6Al4V) pedicle screws were tested in-vitro by conducting a series of potentiostatic measurements of the peak-to-peak values of fretting corrosion current under bending in a 10% solution of calf serum in PBS. The test included Nitinol rods locked in titanium pedicle screws of different designs. Performance of commercially available titanium (Ti6Al4V) and CoCr spinal rods was also investigated for a comparison. Corrosion damage observed after the in-vitro tests was studied using SEM and EDAX analysis and was compared with patterns on Nitinol rods retrieved 12months after initial surgery. Metal ions level was measured in the test media after in-vitro experiments and in the blood and tissues of the patients who had the rods explanted. The results of this study revealed that Nitinol spinal rods locked in Ti pedicle screws are susceptible to fretting corrosion demonstrating higher fretting corrosion current compared with commercially used Ti6Al4V and CoCr rods. On the surface of Nitinol rods after in-vitro tests and on those retrieved from the patients similar corrosion patterns were observed. Improved resistance to fretting corrosion was observed with Nitinol rods in the in-vitro tests where pedicle screws were used with a stiffer locking mechanism. Since the development of the localized corrosion damage might increase the risk of premature fatigue failure of the rods and result in leaching of Ni ions, it is concluded that Nitinol rods should not be used in conjunction with Ti pedicle screws without special protection especially where the

  20. Self-crimping superelastic nitinol prosthesis and malleostapedotomy: a temporal bone study.

    Science.gov (United States)

    Magliulo, Giuseppe

    2013-02-01

    The aim of this study was to compare the results of application of 2 types of superelastic nitinol prostheses. Temporal bones study with planned data collection. Tertiary referral center. Malleostapedotomy was performed in 15 human temporal bones implanting 3 different prostheses: manually crimping polytetrafluoroethylene (MC-PTFE) piston, nitinol self-crimping polytetrafluoroethylene (SC-PTFE) piston, and a modified nitinol self-crimping polytetrafluoroethylene (mSC-PTFE) piston. The first 2 have a diameter of 0.4 mm and length of 7 mm, whereas the mSC-PTFE piston has a diameter of 0.4 mm but a length of 7.75 mm. We evaluated various parameters of prosthesis attachment-that is, the time for implantation of SC and mSC nitinol loop pistons and the MC platinum loop piston, the quality of attachment of the prostheses to the malleus, their positions with respect to the center of the stapes footplate, and the protrusion of the piston into the vestibule. The mSC-PTFE superelastic nitinol prosthesis showed a statistically significant difference in mean operation time (mSC vs SC, P piston into the vestibule was highly reproducible in all 3 prostheses. Because of its greater length, the mSC-PTFE allows for management of the most varied anatomical conditions. At the same time, its self-crimping nature prevents the risk of distortion of the prosthesis by the crimping process and reduces the operation time in combination with standardized bending of the prosthesis shaft.

  1. Contribution to the aluminum–tin–zinc ternary system

    Science.gov (United States)

    Drápala, J.; Kostiuková, G.; Losertová, M.

    2017-11-01

    The Sn–Zn–Al alloys are one of significant candidates in the proposal of alternative lead-free solders for higher temperature soldering. This paper deals with the study of the aluminum–tin–zinc system. Twenty Sn–Zn–Al alloys together with six binary Sn–Zn alloys were prepared and studied experimentally. Alloys were prepared from pure Sn, Zn and Al (melting and cooling in a vacuum resistance furnace). The specimens were studied metallographically including the micro-hardness measurements, complete chemical analysis (ICP-AES, OES), X-ray micro-analysis of alloys by SEM and EDX in order to determine the composition and identification of individual phases. Significant temperatures and enthalpies of phase transformations were determined by DTA. After long-term annealing of selected alloys in vacuum followed by quenching the structural and chemical microanalyses of the present phases and their limit concentrations were carried out. The achieved results were compared with the thermodynamic modelling of the ternary Sn–Zn–Al system (computer programs THERMOCALC, MTDATA, PANDAT and databases CALPHAD, COST). Electrical resistivity, density, magnetic susceptibility and wettability of Sn–Zn–Al solders were measured as well.

  2. In Vivo and In Vitro Nitinol Corrosion Properties

    Science.gov (United States)

    Lonn, Melissa K.; Metcalf, Justin M.; Choules, Brian D.

    2015-09-01

    Regulatory authorities often require in vitro testing on medical devices prior to approval. Current standardized corrosion testing methods (ASTM F2129) require testing in a non-physiologic, de-oxygenated solution for a pre-exposure time of ≤1 h; however, no correlations between the prescribed simulated environment and whole blood conditions have been elucidated. This study compared open circuit potential (OCP), breakdown potentials (Eb), Eb - OCP, and cyclic polarization curves tested in vivo (OCP only) and in vitro in whole blood to those tested in phosphate-buffered saline (PBS). Two oxide thicknesses of Nitinol, two solution oxygen contents (deaerated and aerated solutions), and two pre-exposure durations (acute and chronic) were investigated. The in vitro OCP in whole blood was not significantly different than the in vivo OCP, suggesting that whole blood in vitro can be used to determine baseline corrosion behavior of medical implants. Eb - OCP tested per ASTM F2129 was comparable to acute whole blood and was conservative compared to chronic whole blood for both oxide thicknesses. However, OCP, Eb, and cyclic polarization curves were not always comparable to whole blood. Testing in aerated PBS achieved Eb, Eb - OCP, and cyclic polarization curves that were comparable to or more conservative than whole blood testing, regardless of pre-exposure duration and oxide thickness.

  3. Effect of the selected alloying on Ni-Mn-Ga alloys

    Energy Technology Data Exchange (ETDEWEB)

    Soederberg, O.; Koho, K.; Sammi, T.; Liu, X.W.; Sozinov, A.; Lanska, N.; Lindroos, V.K

    2003-07-25

    The aim of the present study was to investigate the possibilities of changing some characteristics of ternary Ni-Mn-Ga alloys by alloying. Therefore, five quaternary materials were prepared from the same polycrystalline Ni-Mn-Ga master ternary alloy with about 2 at.% additions of Bi, Pb, Si, Sn and Zn. The transformation temperatures and Curie points of the annealed materials were determined with DSC and magnetic susceptibility measurements. The crystal structures of the alloys were determined with the X-ray diffraction. In alloys with Si and Sn phase transformations were retarded to very low temperatures or outside the observable temperature region (below 113 K). With Si alloying a clear premartensitic softening was present. Bi, Pb and Zn doping preserved the original monoclinic crystal structure of the master alloy with slight lattice parameter changes. Bi increased slightly the phase transformation temperatures and decreased the Curie point, while in the two others phase transformations were shifted little lower and Curie temperature to higher temperatures. The intermartensitic transformation present in the ternary alloy was either totally retarded or diminished to a large extent in all of the doped alloys.

  4. The ternary system: Silicon-tantalum-uranium

    Energy Technology Data Exchange (ETDEWEB)

    Rogl, Peter, E-mail: peter.franz.rogl@univie.ac.a [Institute of Physical Chemistry, University of Vienna, A-1090 Wien, Waehringerstrasse 42 (Austria); Noel, Henri [Laboratoire de Chimie du Solide et Materiaux, UMR-CNRS 6226, Universite de Rennes I, Avenue du General Leclerc, F-35042 Rennes, Cedex (France)

    2010-09-01

    Phase equilibria in the ternary system Si-Ta-U have been established in an isothermal section at 1000 {sup o}C by optical microscopy, electron probe microanalysis and X-ray diffraction. Two novel ternary compounds were observed and were characterised by X-ray powder Rietveld refinement: stoichiometric {tau}{sub 1}-U{sub 2}Ta{sub 3}Si{sub 4} (U{sub 2}Mo{sub 3}Si{sub 4}-type, P2{sub 1}/c; a = 0.70011(1), b = 0.70046(1), c = 0.68584(1) nm, ss = 109.38(1); R{sub F} = 0.073, X-ray powder Rietveld refinement) and {tau}{sub 2}-U{sub 2-x}Ta{sub 3+x}Si{sub 4} at x {approx} 0.30 (Sc{sub 2}Re{sub 3}Si{sub 4}-type = partially ordered Zr{sub 5}Si{sub 4}-type, P4{sub 1}2{sub 1}2; a = b = 0.69717(3)(1), c = 1.28709(4) nm; R{sub F} = 0.056; X-ray single crystal data). Mutual solubility of U-silicides and Ta-silicides are found to be very small i.e. below about 1 at.%. Due to the equilibrium tie-line Ta{sub 2}Si-U(Ta), no compatibility exists between the U-rich silicides U{sub 3}Si or U{sub 3}Si{sub 2} and tantalum metal. Single crystals obtained from alloys slowly cooled from liquid (2000 {sup o}C), yielded a fully ordered compound U{sub 2}Ta{sub 2}Si{sub 3}C (unique structure type; Pmna, a = 0.68860(1); b = 2.17837(4); c = 0.69707(1) nm; R{sub F2} = 0.048).

  5. [Numerical modeling of shape memory alloy vascular stent's self-expandable progress and "optimized grid" of stent].

    Science.gov (United States)

    Xu, Qiang; Liu, Yulan; Wang, Biao; He, Jin

    2008-10-01

    Vascular stent is an important medical appliance for angiocardiopathy. Its key deformation process is the expandable progress of stent in the vessel. The important deformation behaviour corresponds to two mechanics targets: deformation and stress. This paper is devoted to the research and development of vascular stent with proprietary intellectual property rights. The design of NiTinol self-expandable stent is optimized by means of finite element software. ANSYS is used to build the finite element simulation model of vascular stent; the molding material is NiTinol shape memory alloy. To cope with the factors that affect the structure of stent, the shape of grid and so on, the self-expanding process of Nitinol stent is simulated through computer. By making a comparison between two kinds of stents with similar grid structure, we present a new concept of "Optimized Grid" of stent.

  6. Amorphous phase formation in the Cu{sub 36}Zr{sub 59}A{sub l5} and Cu{sub 48}Zr{sub 43}A{sub l9} ternary alloys studied by molecular dynamics; Estudo da formacao de fase amorfa nas ligas ternarias Cu{sub 36}Zr{sub 59}A{sub l5} e Cu{sub 48}Zr{sub 43}A{sub l9} por dinamica molecular

    Energy Technology Data Exchange (ETDEWEB)

    Aliaga, L.C.R.; Schimidt, C.S.; Lima, L.V.; Domingues, G.M.B.; Bastos, I.N., E-mail: aliaga@iprj.uer.br [Universidade do Estado do Rio de Janeiro (UERJ), Nova friburgo, RJ (Brazil). Departamento de Materiais

    2016-07-01

    Amorphous alloys presents better mechanical and physical properties than its crystalline counterparts. However, there is a scarce understanding on structure - properties relationship in this class of materials. This paper presents the results of the molecular dynamics application to obtain an atomistic description of melting, solidification and the glass forming ability in the ternary Cu{sub 36}Zr{sub 59}A{sub l5} and Cu{sub 48}Zr{sub 43}A{sub l9} alloys. In the study we used the EAM potential and different cooling rates, β = 0.1, 1 and 100 K/ps to form the amorphous phase in a system consisting of 32,000 atoms by using the free code LAMMPS. The solidus and liquidus temperatures, on a heating rate of the 5 K/ps, were obtained. Also, on the cooling down step, it was observed that the glass transition temperature (T{sub g}) decreases as cooling rate increases. The structural evolution was analyzed through the radial distribution functions and Voronoi polyhedra. Furthermore, it was determined the evolution of viscosity upper T{sub g}, as well as the fragility (m) parameter for each amorphous alloy. The thermal parameters of the simulation obtained are compared with those of the experiments. (author)

  7. Development of Powder Diffraction Analysis Tools for aNanocrystalline Specimen: An Emphasis upon NiTi (Nitinol)

    Energy Technology Data Exchange (ETDEWEB)

    Owens, Erich; /Albion Coll. /SLAC

    2006-08-30

    Powder diffraction is a specialized technique whose investigatory limits are constrained by the scale of the crystallized substance being scanned versus the probe beam used. When disparate in scale, with the photon spot size larger than the crystal being probed, many are employed, the resulting diffraction image being cast from all possible incident angles, constructing {chi}-arcs containing information about the crystalline structure of the material under examination. Of particular interest to our collaboration is the structure of Nitinol, a superelastic Nickel-Titanium alloy, whose phase transformations and load bearing deformations can be studied by usage of diffraction, with wide sweeping biomedical uses. Analysis of this data is complicated by phase transformation and material fluorescence, which make difficult the computational modeling of the peaks within concentric {chi}-arcs. We endeavored to construct a series of computational tools (the amalgamation of them known as 2DPeakFinder) for refining and extracting this relevant data, toward the end of employing previously developed algorithms in the material's structural analysis. We succeeded to a large degree with the use of an iterative algorithm to navigate radial complexity of the signal and manage to retain a distinction between useful signal and superfluous background noise. The tools developed in this project are a small step in readily streamlining the analysis and physical modeling of a Nanocrystalline material's structural properties.

  8. Optical Characterization of AlAsSb Digital Alloy and Random Alloy on GaSb

    Directory of Open Access Journals (Sweden)

    Bor-Chau Juang

    2017-10-01

    Full Text Available III-(As, Sb alloys are building blocks for various advanced optoelectronic devices, but the growth of their ternary or quaternary materials are commonly limited by spontaneous formation of clusters and phase separations during alloying. Recently, digital alloy growth by molecular beam epitaxy has been widely adopted in preference to conventional random alloy growth because of the extra degree of control offered by the ordered alloying. In this article, we provide a comparative study of the optical characteristics of AlAsSb alloys grown lattice-matched to GaSb using both techniques. The sample grown by digital alloy technique showed stronger photoluminescence intensity, narrower peak linewidth, and larger carrier activation energy than the random alloy technique, indicating an improved optical quality with lower density of non-radiative recombination centers. In addition, a relatively long carrier lifetime was observed from the digital alloy sample, consistent with the results obtained from the photoluminescence study.

  9. Data transmission is faster with ternary coding

    CERN Document Server

    Bruins, T

    1974-01-01

    Discusses a ternary data transmission system for an effective rate of up to 6 megabits per second over a 1-mile line of ordinary twisted- pair cable. The methods are discussed of implementing a ternary data transmission system. (0 refs).

  10. Bandgap and Structure Engineering via Cation Exchange: From Binary Ag2S to Ternary AgInS2, Quaternary AgZnInS alloy and AgZnInS/ZnS Core/Shell Fluorescent Nanocrystals for Bioimaging.

    Science.gov (United States)

    Song, Jiangluqi; Ma, Chao; Zhang, Wenzhe; Li, Xiaodong; Zhang, Wenting; Wu, Rongbo; Cheng, Xiangcan; Ali, Asad; Yang, Mingya; Zhu, Lixin; Xia, Ruixiang; Xu, Xiaoliang

    2016-09-21

    Attention on semiconductor nanocrystals have been largely focused because of their unique optical and electrical properties, which can be applied as light absorber and luminophore. However, the band gap and structure engineering of nanomaterials is not so easy because of their finite size. Here we demonstrate an approach for preparing ternary AgInS2 (AIS), quaternary AgZnInS (AZIS), AgInS2/ZnS and AgZnInS/ZnS nanocompounds based on cation exchange. First, pristine Ag2S quantum dots (QDs) with different sizes were synthesized in one-pot, followed by the partial cation exchange between In(3+) and Ag(+). Changing the initial ratio of In(3+) to Ag(+), reaction time and temperature can control the components of the obtained AIS QDs. Under the optimized conditions, AIS QDs were obtained for the first time with a cation disordered cubic phase and high photoluminescence (PL) quantum yield (QY) up to 32% in aqueous solution, demonstrating the great potential of cation exchange in the synthesis for nanocrystals with excellent optical properties. Sequentially, Zn(2+) ions were incorporated in situ through a second exchange of Zn(2+) to Ag(+)/In(3+), leading to distinct results under different reaction temperature. Addition of Zn(2+) precursor at room temperature produced AIS/ZnS core/shell NCs with successively enhancement of QY, while subsequent heating could obtain AZIS homogeneous alloy QDs with a successively blue-shift of PL emission. This allow us to tune the PL emission of the products from 483 to 675 nm and fabricate the chemically stable QDs core/ZnS shell structure. Based on the above results, a mechanism about the cation exchange for the ternary nanocrystals of different structures was proposed that the balance between cation exchange and diffusion is the key factor of controlling the band gap and structure of the final products. Furthermore, photostability and in vitro experiment demonstrated quite low cytotoxicity and remarkably promising applications in the

  11. [Application of damper craniofixators from nitinol in plasty of skull defects].

    Science.gov (United States)

    Gevorkov, A V; Davydov, E A; Safarov, B I; Il'in, A A; Kollerov, M Iu; Cheremkin, S N; Ulitin, A Iu

    2010-01-01

    An overview of the methods of fixation of the skull bones is presented,as well as discussion and characterization of different methods of fixation. A new system of fixation of the skull bones was used in osseous-plastic trepanation and reconstructive operations using nitinol craniofixators. Results of cranioplasty using craniofixators were analyzed in 62 patients with craniocerebral injuries and its consequences, vascular and oncological diseases of the brain. There were no complications in the postoperative period. Articles made of nitinol are very strong, elastic and have the effect of thermo-mechanical memory of the form.

  12. Recentering Shape Memory Alloy Passive Damper for Structural Vibration Control

    Directory of Open Access Journals (Sweden)

    Hui Qian

    2013-01-01

    Full Text Available This paper presents a preliminary study on the evaluation of an innovative energy dissipation system with shape memory alloys (SMAs for structural seismic protection. A recentering shape memory alloy damper (RSMAD, in which superelastic nitinol wires are utilized as energy dissipation components, is proposed. Improved constitutive equations based on Graesser and Cozzarelli model are proposed for superelastic nitinol wires used in the damper. Cyclic tensile-compressive tests on the damper with various prestrain under different loading frequencies and displacement amplitudes were conducted. The results show that the hysteretic behaviors of the damper can be modified to best fit the needs for passive structural control applications by adjusting the pretension of the nitinol wires, and the damper performance is not sensitive to frequencies greater than 0.5 Hz. To assess the effectiveness of the dampers for structural seismic protection, nonlinear time history analysis on a ten-story steel frame with and without the dampers subjected to representative earthquake ground motions was performed. The simulation results indicate that superelastic SMA dampers are effective in mitigating the structural response of building structures subjected to strong earthquakes.

  13. Investigation of crystal structures of one-way shape memory Nitinol wire actuators for active steerable needle

    Science.gov (United States)

    Honarvar, Mohammad; Konh, Bardia; Hutapea, Parsaoran

    2015-04-01

    Due to its outstanding properties of Nitinol, known as shape memory and superelasticity, Nitinol wires have been used as actuators in many medical devices. For the medical applications, it is critical to have a consistent strain response of Nitinol wires. This work focuses on studying the effect of parameters such as biased stress, maximum temperature, and wire diameters that influence the strain response of Nitinol wires. Specifically, Nitinol phase transformations were studied from microstructural point of view. The crystal structures of one-way shape memory Nitinol wires of various diameters under different thermomechanical loading conditions were studied using X-Ray Diffraction (XRD) method. The location and intensity of characteristic peaks were determined prior and after the thermomechanical loading cycles. It was observed that Nitinol wires of diameters less than 0.19 mm exhibit unrecovered strain while heated to the range of 70ºC to 80ºC in a thermal cycle, whereas no unrecovered strains were found in larger wires. The observation was supported by the XRD patterns where the formation of R-phase crystal structure was showed in wire diameters less than 0.19 mm at room temperature.

  14. Data and analyses of phase relations in the Ce-Fe-Sb ternary system.

    Science.gov (United States)

    Zhu, Daiman; Xu, Chengliang; Li, Changrong; Guo, Cuiping; Zheng, Raowen; Du, Zhenmin; Li, Junqin

    2018-02-01

    These data and analyses support the research article "Experimental study on phase relations in the Ce-Fe-Sb ternary system" Zhu et al. (2017) [1]. The data and analyses presented here include the experimental results of XRD, SEM and EPMA for the determination of the whole liquidus projection and the isothermal section at 823 K in the Ce-Fe-Sb system. All the results enable the understanding of the constituent phases and the solidification processes of the as-cast alloys as well as the phase relations and the equilibrium regions at 823 K in the Ce-Fe-Sb ternary system over the entire composition.

  15. Application of Taguchi method to optimization of surface roughness during precise turning of NiTi shape memory alloy

    Science.gov (United States)

    Kowalczyk, M.

    2017-08-01

    This paper describes the research results of surface quality research after the NiTi shape memory alloy (Nitinol) precise turning by the tools with edges made of polycrystalline diamonds (PCD). Nitinol, a nearly equiatomic nickel-titanium shape memory alloy, has wide applications in the arms industry, military, medicine and aerospace industry, and industrial robots. Due to their specific properties NiTi alloys are known to be difficult-to-machine materials particularly by using conventional techniques. The research trials were conducted for three independent parameters (vc, f, ap) affecting the surface roughness were analyzed. The choice of parameter configurations were performed by factorial design methods using orthogonal plan type L9, with three control factors, changing on three levels, developed by G. Taguchi. S/N ratio and ANOVA analyses were performed to identify the best of cutting parameters influencing surface roughness.

  16. Phase equilibria of the Mo-Al-Ho ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yitai; Chen, Xiaoxian; Liu, Hao [Guangxi Univ., Nanning (China). College of Materials Science and Engineering; Guangxi Univ., Nanning (China). Guangxi Key Laboratory of Processing for Non-ferrous Metal and Featured Materials; Zhan, Yongzhong [Guangxi Univ., Nanning (China). College of Materials Science and Engineering; Guangxi Univ., Nanning (China). Guangxi Key Laboratory of Processing for Non-ferrous Metal and Featured Materials; Guangxi Univ., Nanning (China). Center of Ecological Collaborative Innovation for Aluminum Industry

    2017-08-15

    Investigation into the reactions and phase equilibria of transition metal elements (i.e. Mo, Zr, Cr, V and Ti), Al and rare earths is academically and industrially important for the development of both refractory alloys and lightweight high-temperature materials. In this work, the equilibria of the Mo-Al-Ho ternary system at 773 K have been determined by using X-ray powder diffraction and scanning electron microscopy equipped with energy dispersive X-ray analysis. A new ternary phase Al{sub 4}Mo{sub 2}Ho has been found and the other ternary phase Al{sub 43}Mo{sub 4}Ho{sub 6} is observed. Ten binary phases in the Al-Mo and Al-Ho systems, including Al{sub 17}Mo{sub 4} rather than Al{sub 4}Mo, have been determined to exist at 773 K. The homogeneity ranges of AlMo{sub 3} and Al{sub 8}Mo{sub 3} phase are 7.5 at.% and 1 at.%, respectively. According to the phase-disappearing method, the maximum solubility of Al in Mo is about 16 at.%.

  17. On the Mechanical Properties and Microstructure of Nitinol forBiomedical Stent Applications

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, Scott W. [Univ. of California, Berkeley, CA (United States)

    2006-01-01

    This dissertation was motivated by the alarming number of biomedical device failures reported in the literature, coupled with the growing trend towards the use of Nitinol for endovascular stents. The research is aimed at addressing two of the primary failure modes in Nitinol endovascular stents: fatigue-crack growth and overload fracture. The small dimensions of stents, coupled with their complex geometries and variability among manufacturers, make it virtually impossible to determine generic material constants associated with specific devices. Instead, the research utilizes a hybrid of standard test techniques (fracture mechanics and x-ray micro-diffraction) and custom-designed testing apparatus for the determination of the fracture properties of specimens that are suitable representations of self-expanding Nitinol stents. Specifically, the role of texture (crystallographic alignment of atoms) and the austenite-to-martensite phase transformation on the propagation of cracks in Nitinol was evaluated under simulated body conditions and over a multitude of stresses and strains. The results determined through this research were then used to create conservative safe operating and inspection criteria to be used by the biomedical community for the determination of specific device vulnerability to failure by fracture and/or fatigue.

  18. Mesoscale inhomogeneities in an aqueous ternary system

    Science.gov (United States)

    Subramanian, Deepa; Hayward, Stephen; Altabet, Elia; Collings, Peter; Anisimov, Mikhail

    2012-02-01

    Aqueous solutions of certain low-molecular-weight organic compounds, such as alcohols, amines, or ethers, which are considered macroscopically homogeneous, show the presence of mysterious mesoscale inhomogeneities, order of a hundred nm in size. We have performed static and dynamic light scattering experiments in an aqueous ternary system consisting of tertiary butyl alcohol and propylene oxide. Tertiary butyl alcohol is completely soluble in water and in propylene oxide, and forms strong hydrogen bonds with water molecules. Based on results of the study, we hypothesize that the mesoscale inhomogeneities are akin to a micro phase separation, resulting from a competition between water molecules and propylene oxide molecules, wanting to be adjacent to amphiphilic tertiary butyl alcohol molecules. Coupling between two competing order parameters, super-lattice binary-alloy-like (``antiferromagnetic'' type) and demixing (``ferromagnetic'' type) may explain the formation of these inhomogeneities. Long-term stability investigation of this supramolecular structure has revealed that these inhomogeneities are exceptionally long-lived non-equilibrium structures that persist for weeks or even months.

  19. Research and Development on Titanium Alloys

    Science.gov (United States)

    1949-10-31

    are being prepared by the Norton Company for evaluation. Titanium boride , tantalum boride , zirconium boride , tungsten boride , and molybdenum boride ...alloying additionO will be ex- tended. 9 Ternary alloys of manganese and carbon, manganese and vanadium, and molybdenum and tungsten, prepared by...graphite crucibles lined with tantalum carbide and turgsten boride as refractories for molten titanium,. Melts were prepared In crucibles made of zirconium

  20. Laser alloyed Al-Ni-Fe coatings

    CSIR Research Space (South Africa)

    Pityana, SL

    2008-10-01

    Full Text Available The aim of this work was to produce crack-free thin surface layers consisting of binary (Al-Ni, Al-Fe) and ternary (Al-Ni-Fe) intermetallic phases by means of a high power laser beam. The laser surface alloying was carried out by melting Fe and Ni...

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

    Science.gov (United States)

    Hudish, Grant A.

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

  2. Microstructural evolution and thermal stability of aluminum-cerium-nickel ternary eutectic

    Science.gov (United States)

    Fodran, Eric John

    The engineering community has identified several applications in which the use of a lightweight alloy for elevated temperature service, in substitution for current heavier and more costly alloys, would have a substantial benefit. This need for structural materials to perform at elevated temperatures has driven researchers to develop novel alloys as well as processing routes to manufacture them and obtain optimum microstructures. Previous studies on aluminum based binary eutectic systems have proven that the aluminum alloy system shows promising potential for satisfying this need. This has motivated the investigation of the solidification and thermal stability of the Al-12 wt% Ce-5 wt% Ni ternary eutectic performed in this investigation. The solidification behavior of the Al-Ce-Ni ternary eutectic was conducted via solidification of various compositions at and above the eutectic composition in a copper chill mold, thus allowing the observation of various solidification rates on a single ingot. Directional solidification of the ternary eutectic was also conducted to further study the unique microstructures forms. After casting the ingots were analyzed for the composition of phases in the microstructure via X-ray diffraction, and the distribution of the phases determined by scanning electron microscopy. The solidification of the ternary eutectic was found to occur much like that of a faceted/non-faceted binary couples growth. The thermal stability of the microstructure was also studied. Ternary eutectic microstructures were heat treated at various temperatures for time intervals up to 100 hours. The coupled growth microstructures were found to coarsen at temperature above 400°C, which was associated with a loss in hardness. Coarsening of the microstructures at elevated temperatures was also observed to occur by multiple mechanisms: an Ostwald ripening within the eutectic cell, and an accelerated coarsening at the cell boundaries due to increased diffusion at

  3. Some new ternary linear codes

    Directory of Open Access Journals (Sweden)

    Rumen Daskalov

    2017-07-01

    Full Text Available Let an $[n,k,d]_q$ code be a linear code of length $n$, dimension $k$ and minimum Hamming distance $d$ over $GF(q$. One of the most important problems in coding theory is to construct codes with optimal minimum distances. In this paper 22 new ternary linear codes are presented. Two of them are optimal. All new codes improve the respective lower bounds in [11].

  4. A simple method for determining the lattice parameter and chemical composition in ternary bcc-Fe rich nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Moya, Javier A., E-mail: jmoya.fi.uba@gmail.com [Grupo Interdisciplinario en Materiales-IESIING, Universidad Católica de Salta, INTECIN UBA-CONICET, Salta (Argentina); Gamarra Caramella, Soledad; Marta, Leonardo J. [Grupo Interdisciplinario en Materiales-IESIING, Universidad Católica de Salta, INTECIN UBA-CONICET, Salta (Argentina); Berejnoi, Carlos [Universidad Nacional de Salta, Facultad de Ingeniería, Salta (Argentina)

    2015-05-15

    Highlights: • A method for determining composition in ternary nanocrystals is presented. • X-ray diffraction and Mössbauer spectroscopy data were employed. • We perform theoretical charts for lattice parameter of Fe-rich ternary alloys. • A linear relationship in lattice parameter for binary alloys is evaluated. • A parabolic relationship is proposed for the Fe–Co–Si alloy. - Abstract: Charts containing lattice parameters of Fe{sub 1−x}(M,N){sub x} ternary systems with M and N = Si, Al, Ge or Co, and 0 ⩽ x ⩽ ∼0.3, were developed by implementing a linear relationship between the respective binary alloys with the same solute content of the ternary one. Charts were validated with experimental data obtained from literature. For the Fe–Co–Si system, the linear relationship does not fit the experimental data. For the other systems (except the Fe–Co–Ge one where no experimental data was found), the lineal relationship constitute a very good approximation. Using these charts and the lattice parameter data obtained from X-ray diffraction technique combining with the solute content data obtained from Mössbauer spectroscopy technique it is possible to determine the chemical composition of nanograins in soft magnetic nanocomposite materials and some examples are provided.

  5. Density functional theory based screening of ternary alkali-transition metal borohydrides: A computational material design project

    DEFF Research Database (Denmark)

    Hummelshøj, Jens Strabo; Landis, David; Voss, Johannes

    2009-01-01

    We present a computational screening study of ternary metal borohydrides for reversible hydrogen storage based on density functional theory. We investigate the stability and decomposition of alloys containing 1 alkali metal atom, Li, Na, or K (M1); and 1 alkali, alkaline earth or 3d/4d transition...

  6. Nearly Ternary Quadratic Higher Derivations on Non-Archimedean Ternary Banach Algebras: A Fixed Point Approach

    Directory of Open Access Journals (Sweden)

    M. Eshaghi Gordji

    2011-01-01

    Full Text Available We investigate the stability and superstability of ternary quadratic higher derivations in non-Archimedean ternary algebras by using a version of fixed point theorem via quadratic functional equation.

  7. Ternary cobalt-molybdenum-zirconium coatings for alternative energies

    Science.gov (United States)

    Yar-Mukhamedova, Gulmira; Ved', Maryna; Sakhnenko, Nikolay; Koziar, Maryna

    2017-11-01

    Consistent patterns for electrodeposition of Co-Mo-Zr coatings from polyligand citrate-pyrophosphate bath were investigated. The effect of both current density amplitude and pulse on/off time on the quality, composition and surface morphology of the galvanic alloys were determined. It was established the coating Co-Mo-Zr enrichment by molybdenum with current density increasing up to 8 A dm-2 as well as the rising of pulse time and pause duration promotes the content of molybdenum because of subsequent chemical reduction of its intermediate oxides by hydrogen ad-atoms. It was found that the content of the alloying metals in the coating Co-Mo-Zr depends on the current density and on/off times extremely and maximum Mo and Zr content corresponds to the current density interval 4-6 A dm-2, on-/off-time 2-10 ms. Chemical resistance of binary and ternary coatings based on cobalt is caused by the increased tendency to passivity and high resistance to pitting corrosion in the presence of molybdenum and zirconium, as well as the acid nature of their oxides. Binary coating with molybdenum content not less than 20 at.% and ternary ones with zirconium content in terms of corrosion deep index are in a group ;very proof;. It was shown that Co-Mo-Zr alloys exhibits the greatest level of catalytic properties as cathode material for hydrogen electrolytic production from acidic media which is not inferior a platinum electrode. The deposits Co-Mo-Zr with zirconium content 2-4 at.% demonstrate high catalytic properties in the carbon(II) oxide conversion. This confirms the efficiency of materials as catalysts for the gaseous wastes purification and gives the reason to recommend them as catalysts for red-ox processes activating by oxygen as well as electrode materials for red-ox batteries.

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

    Directory of Open Access Journals (Sweden)

    Sravya Tekumalla

    2014-12-01

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

  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. Composition dependences of thermodynamical properties associated with Pb-free ternary, quaternary, and quinary solder systems

    Science.gov (United States)

    Dogan, A.; Arslan, H.

    2016-05-01

    In the present study, Chou's General Solution Model (GSM) has been used to predict the enthalpy and partial enthalpies of mixing of the liquid Ag-In-Sn ternary, Ag-In-Sn-Zn quaternary, and Ag-Au-In-Sn-Zn quinary systems. These are of technical importance to optimize lead-free solder alloys, in selected cross-sections: x In/ x Sn = 0.5/0.5 (ternary), Au-In0.1-Sn0.8-Zn0.1, Ag-In0.1-Sn0.8-Zn0.1 (quaternary), and t = x Au/ x In = 1, x In = x Sn = x Zn (quinary) at 1173, 773, and 773 K, respectively. Moreover, the activity of In content in the ternary alloy system Ag-In-Sn has been calculated and its result is compared with that determined from the experiment, while the activities of Ag contents associated with the alloys mentioned above have been calculated. The other traditional models such as of Colinet, Kohler, Muggianu, Toop, and Hillert are also included in calculations. Comparing those calculated from the proposed GSM with those determined from experimental measurements, it is seen that this model becomes considerably realistic in computerization for estimating thermodynamic properties in multicomponent systems.

  11. NiTi Alloys for Tribological Applications: The Role of In-Situ Nanotechnology

    Science.gov (United States)

    Dellacorte, Christopher

    2016-01-01

    Beginning in 2004, NASA initiated the investigation and development of, Nitinol 60, a nickel-rich and dimensionally stable version of shape memory alloy Nitinol 55, as an alternative to bearing steel. Early investigations showed it to be hard and impervious to aqueous corrosion but the fundamental reasons for these properties were unknown. Shape memory alloys made from equiatomic Ni-Ti are widely known for their unique dimensional instability behavior that can be triggered by thermal and mechanical stress. The nickel-rich alloys exhibit no such dimension change property and have high hardness but have largely been overlooked by industry and the engineering community. Though steel is the dominant material of choice for mechanical components (bearings and gears) it has intrinsic limitations related to corrosion and plastic deformation. In contrast, Ni-Ti alloys are intrinsically rustproof and can withstand high contact loads without damage (denting). Over the last decade, focused RD to exploit these alloys for new applications has revealed that in-situ nano-scale phases that form during processing are largely responsible for NiTis remarkable properties. In this presentation, the state-of-art of nickel-rich NiTi alloys will be introduced and the nanotechnology behind their intriguing behavior will be addressed. The presentation will include discussion of how NASA is adopting this new technology inside the space station water recycling system as a pathfinder for more down-to-earth tribological challenges.

  12. Cytotoxicity of Ni from Surface-Treated Porous Nitinol (PNT) on Osteoblast Cells

    OpenAIRE

    Pulletikurthi, C.; Munroe, N.; Gill, P.; Pandya, S.; Persaud, D.; Haider, W; Iyer, K.; McGoron, A.

    2011-01-01

    The leaching of nickel from the surface of porous Nitinol (PNT) is mainly dependent on its surface characteristics, which can be controlled by appropriate surface treatments. In this investigation, PNT was subjected to two surface treatments, namely, water-boiling and dry-heating passivations. Phosphate buffer saline (PBS) solutions obtained from cyclic potentiodynamic polarization tests on PNT were employed to assess the cytotoxicity of Ni contained therein on osteoblast cells by Sulforhodam...

  13. Treatment of malignant gastroduodenal obstruction with using a newly designed complex expandable nitinol stent: initial experiences

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Mi Hee; Ko, Ji Ho; Lee, Eun Jung; Oh, Kyeng Seung; Huh, Jin Do; Cho, Young Duk; Park, Seun Ja [College of Medicine, Kosin University, Busan (Korea, Republic of); Jung, Gyoo Sik [Ulsan Hospital, Ulsan (Korea, Republic of)

    2005-12-15

    We wanted to evaluate the usefulness of a new type of a complex expandable nitinol stent that was designed to reduce the stent's propensity to migration during the treatment of malignant gastroduodenal obstructions. Two types of expandable nitinol stent were constructed by weaving a single thread of 0.2mm nitinol wire in a tubular configuration: an uncovered stent 18mm in diameter and a covered stent 16mm in diameter. Both ends of the covered stent were fabricated by coaxially inserting the covered stent into the tubular uncovered stent and then attaching the two stents together with using nylon monofilament. Under fluoroscopic guidance, the stent was placed in 29 consecutive patients (20 men and 9 women, mean age: 65 years) who were suffering with malignant gastric outlet obstruction (n=20), duodenal obstruction (n=6) or combined obstruction (n=3). Clinical improvement was assessed by comparing the food intake capacity before and after the procedure. The complications were investigated during the follow up period. Stent placement was successful in all the patients. After stent placement, the symptoms improved in all but one patient. During the follow up, stent migration occurred in one patient (3%) at 34 days after the procedure. Despite the stent migration, the patient was able to resume a soft diet. Six patients developed recurrent symptoms of obstruction with tumor overgrowth at a mean of 145 days after the procedure; all the patients underwent coaxial placement of an additional stent with good results. One patient showed recurrence of obstruction due to tumor in-growth, and this was treated by placement of a second stent. Two patients with stent placement in the duodenum suffered from jaundice 26 days and 65 days, respectively, after their procedures. Placement of the newly designed complex expandable nitinol stent seems to be effective for the palliative treatment of malignant gastroduodenal obstructions. The new stent also seems to help overcome the

  14. Corrosion resistance, chemistry, and mechanical aspects of Nitinol surfaces formed in hydrogen peroxide solutions

    Energy Technology Data Exchange (ETDEWEB)

    Shabalovskay, Svetlana A.; Anderegg, James W.; Undisz, Andreas; Rettenmayr, Markus; Rondelli, Gianni C.

    2012-06-12

    Ti oxides formed naturally on Nitinol surfaces are only a few nanometers thick. To increase their thickness, heat treatments are explored. The resulting surfaces exhibit poor resistance to pitting corrosion. As an alternative approach to accelerate surface oxidation and grow thicker oxides, the exposure of Nitinol to strong oxidizing H2O2 aqueous solutions (3 and 30%) for various periods of time was used. Using X-Ray Photoelectron Spectroscopy (XPS) and Auger spectroscopy, it was found that the surface layers with variable Ti (6–15 at %) and Ni (5–13 at %) contents and the thickness up to 100 nm without Ni-enriched interfaces could be formed. The response of the surface oxides to stress in superelastic regime of deformations depended on oxide thickness. In the corrosion studies performed in both strained and strain-free states using potentiodynamic and potentiostatic polarizations, the surfaces treated in H2O2 showed no pitting in corrosive solution that was assigned to higher chemical homogeneity of the surfaces free of secondary phases and inclusions that assist better biocompatibility of Nitinol medical devices. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 100B: 1490–1499, 2012

  15. Nano-Impact (Fatigue Characterization of As-Deposited Amorphous Nitinol Thin Film

    Directory of Open Access Journals (Sweden)

    Rehan Ahmed

    2012-08-01

    Full Text Available This paper presents nano-impact (low cycle fatigue behavior of as-deposited amorphous nitinol (TiNi thin film deposited on Si wafer. The nitinol film was 3.5 µm thick and was deposited by the sputtering process. Nano-impact tests were conducted to comprehend the localized fatigue performance and failure modes of thin film using a calibrated nano-indenter NanoTest™, equipped with standard diamond Berkovich and conical indenter in the load range of 0.5 mN to 100 mN. Each nano-impact test was conducted for a total of 1000 fatigue cycles. Depth sensing approach was adapted to understand the mechanisms of film failure. Based on the depth-time data and surface observations of films using atomic force microscope, it is concluded that the shape of the indenter test probe is critical in inducing the localized indentation stress and film failure. The measurement technique proposed in this paper can be used to optimize the design of nitinol thin films.

  16. Effect of Applied Potential on Fatigue Life of Electropolished Nitinol Wires

    Science.gov (United States)

    Sivan, Shiril; Di Prima, Matthew; Weaver, Jason D.

    2017-09-01

    Nitinol is used as a metallic biomaterial in medical devices due to its shape memory and pseudoelastic properties. The clinical performance of nitinol depends on factors which include the surface finish, the local environment, and the mechanical loads to which the device is subjected. Preclinical evaluations of device durability are performed with fatigue tests while electrochemical characterization methods such as ASTM F2129 are employed to evaluate corrosion susceptibility by determining the rest potential and breakdown potential. However, it is well established that the rest potential of a metal surface can vary with the local environment. Very little is known regarding the influence of voltage on fatigue life of nitinol. In this study, we developed a fatigue testing method in which an electrochemical system was integrated with a rotary bend wire fatigue tester. Samples were fatigued at various strain levels at electropotentials anodic and cathodic to the rest potential to determine if it could influence fatigue life. Wires at potentials negative to the rest potential had a significantly higher number of cycles to fracture than wires held at potentials above the breakdown potential. For wires for which no potential was applied, they had fatigue life similar to wires at negative potentials.

  17. Irradiation-Assisted Stress-Corrosion Cracking of Nitinol During eBeam Sterilization

    Science.gov (United States)

    Smith, Stuart A.; Gause, Brock; Plumley, David; Drexel, Masao J.

    2012-12-01

    Medical device fractures during gamma and electron beam (eBeam) sterilization have been reported. Two common factors in these device fractures were a constraining force and the presence of fluorinated ethylene propylene (FEP). This study investigated the effects of eBeam sterilization on constrained light-oxide nitinol wires in FEP. The goal was to recreate these fractures and determine their root cause. Superelastic nitinol wires were placed inside FEP tubes and constrained with nominal outer fiber strains of 10, 15, and 20%. These samples were then subjected to a range of eBeam sterilization doses up to 400 kGy and compared with unconstrained wires also subjected to sterilization. Fractures were observed at doses of >100 kGy. Analysis of the fracture surfaces indicated that the samples failed due to irradiation-assisted stress-corrosion cracking (IASCC). This same effect was also observed to occur with PTFE at 400 kGy. These results suggest that nitinol is susceptible to IASCC when in the presence of a constraining stress, fluorinated polymers, and irradiation.

  18. 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.

  19. On Some Ternary LCD Codes

    OpenAIRE

    Darkunde, Nitin S.; Patil, Arunkumar R.

    2018-01-01

    The main aim of this paper is to study $LCD$ codes. Linear code with complementary dual($LCD$) are those codes which have their intersection with their dual code as $\\{0\\}$. In this paper we will give rather alternative proof of Massey's theorem\\cite{8}, which is one of the most important characterization of $LCD$ codes. Let $LCD[n,k]_3$ denote the maximum of possible values of $d$ among $[n,k,d]$ ternary $LCD$ codes. In \\cite{4}, authors have given upper bound on $LCD[n,k]_2$ and extended th...

  20. Calculation of ternary Si-Fe-Al phase equilibrium in vacuum distillation by molecular interaction volume model

    Directory of Open Access Journals (Sweden)

    Liu K.

    2014-01-01

    Full Text Available The vacuum distillation of aluminum from Si-Fe-Al ternary alloy with high content of Al is studied by a molecular interaction volume model (MIVM in this paper. The vapor-liquid phase equilibrium of the Si-Fe-Al system in vacuum distillation has been calculated using only the properties of pure components and the activity coefficients. A significant advantage of the model lies in its ability to predict the thermodynamic properties of liquid alloys using only binary infinite dilution activity coefficients. The thermodynamic activities and activity coefficients of components of the related Si-Fe, Si- Al and Fe-Al binary and the Si-Fe-Al ternary alloy systems are calculated based on the MIVM. The computational activity values are presented graphically, and evaluated with the reported experiment data in the literature, which shows that the prediction effect of the proposed model is of stability and reliability.

  1. Superconducting state parameters of ternary metallic glasses

    Indian Academy of Sciences (India)

    Administrator

    pseudopotential to ternary metallic glasses involves the assumption of pseudoions with average properties, which are assumed to replace three types of ions in the ternary systems, and a gas of free electrons is assumed to perme- ate through them. The electron–pseudoion is accounted by the pseudopotential, and the ...

  2. Ternary rhythm and the lapse constraint

    NARCIS (Netherlands)

    Elenbaas, N.; Kager, R.W.J.

    2004-01-01

    Ternary rhythmic systems differ from binary systems in stressing every third syllable in a word, rather than every second. Ternary rhythm is well-established for only a small group of languages, including Chugach Alutiiq, Cayuvava, and Estonian, and possibly Winnebago. Nevertheless the stress

  3. High-Efficient Circuits for Ternary Addition

    Directory of Open Access Journals (Sweden)

    Reza Faghih Mirzaee

    2014-01-01

    Full Text Available New ternary adders, which are fundamental components of ternary addition, are presented in this paper. They are on the basis of a logic style which mostly generates binary signals. Therefore, static power dissipation reaches its minimum extent. Extensive different analyses are carried out to examine how efficient the new designs are. For instance, the ternary ripple adder constructed by the proposed ternary half and full adders consumes 2.33 μW less power than the one implemented by the previous adder cells. It is almost twice faster as well. Due to their unique superior characteristics for ternary circuitry, carbon nanotube field-effect transistors are used to form the novel circuits, which are entirely suitable for practical applications.

  4. Heat storage in alloy transformations

    Science.gov (United States)

    Birchenall, C. E.

    1980-01-01

    The feasibility of using metal alloys as thermal energy storage media was investigated. The elements selected as candidate media were limited to aluminum, copper, magnesium, silicon, zinc, calcium, and phosphorus on the basis of low cost and latent heat of transformation. Several new eutectic alloys and ternary intermetallic phases were determined. A new 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. The method and apparatus are discussed and the experimental results are presented for aluminum and two aluminum-eutectic alloys. Candidate materials were evaluated to determine suitable materials for containment of the metal alloys. Graphite was used to contain the alloys during the volume change measurements. Silicon carbide was identified as a promising containment material and surface-coated iron alloys were also evaluated. System considerations that are pertinent if alloy eutectics are used as thermal energy storage media are discussed. Potential applications to solar receivers and industrial furnaces are illustrated schematically.

  5. Optical characterization of one-step synthesis of ternary nanoalloy by laser ablation of stainless steel target in Hexane

    Science.gov (United States)

    Soliman, Wafaa; El-Ansary, Sara; Badr, Yehia

    2017-12-01

    In this work, we ablated stainless steel target in Hexane by 355 nm by tuning laser power to synthesize ternary nanoalloys from its constituents. XRD patterns didn't match with any machine code of carbides, carbonyls and oxides of target elements. Also, they didn't match with any of binary alloys, suggesting the formation of carbides or carbonyls of ternary nanoalloys. In addition, the optical properties of nanoalloys confirms the resonance fluorescence and multistep excitation. By tuning laser power, the shape of nanoalloys is controlled.

  6. A high-throughput search for new ternary superalloys

    Science.gov (United States)

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

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

  7. A study of phase separation in ternary alloys

    Indian Academy of Sciences (India)

    Unknown

    BB. A. 2. AB. B. 2. BB c. K c. K cf. M. ∇. −. ∇. −. ∂∂∇. +. (4) where Mij are the effective mobilities; KAA = KA + KC,. KBB = KB + KC and KAB = KBA = KC. We have used a characteristic length l* = Tk. K. B. 2/1. A. 2/)*( and a chara- cteristic time, t* = )**/. (. 2. AA. B l. MTk to render the above equations non-dimensional; the ...

  8. Ternary alloy material prediction using genetic algorithm and cluster expansion

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chong [Iowa State Univ., Ames, IA (United States)

    2015-12-01

    This thesis summarizes our study on the crystal structures prediction of Fe-V-Si system using genetic algorithm and cluster expansion. Our goal is to explore and look for new stable compounds. We started from the current ten known experimental phases, and calculated formation energies of those compounds using density functional theory (DFT) package, namely, VASP. The convex hull was generated based on the DFT calculations of the experimental known phases. Then we did random search on some metal rich (Fe and V) compositions and found that the lowest energy structures were body centered cube (bcc) underlying lattice, under which we did our computational systematic searches using genetic algorithm and cluster expansion. Among hundreds of the searched compositions, thirteen were selected and DFT formation energies were obtained by VASP. The stability checking of those thirteen compounds was done in reference to the experimental convex hull. We found that the composition, 24-8-16, i.e., Fe3VSi2 is a new stable phase and it can be very inspiring to the future experiments.

  9. Corrosion resistance improvement of titanium base alloys

    Directory of Open Access Journals (Sweden)

    Mihai V. Popa

    2010-01-01

    Full Text Available The corrosion resistance of the new Ti-6Al-4V-1Zr alloy in comparison with ternary Ti-6Al-4V alloy in Ringer-Brown solution and artificial Carter-Brugirard saliva of different pH values was studied. In Ringer-Brown solution, the new alloy presented an improvement of all electrochemical parameters due to the alloying with Zr; also, impedance spectra revealed better protective properties of its passive layer. In Carter-Brugirard artificial saliva, an increase of the passive film thickness was proved. Fluoride ions had a slight negative influence on the corrosion and ion release rates, without to affect the very good stability of the new Ti-6Al-4V-1Zr alloy.

  10. Performance Estimation for Lowpass Ternary Filters

    Directory of Open Access Journals (Sweden)

    Brenton Steele

    2003-11-01

    Full Text Available Ternary filters have tap values limited to −1, 0, or +1. This restriction in tap values greatly simplifies the multipliers required by the filter, making ternary filters very well suited to hardware implementations. Because they incorporate coarse quantisation, their performance is typically limited by tap quantisation error. This paper derives formulae for estimating the achievable performance of lowpass ternary filters, thereby allowing the number of computationally intensive design iterations to be reduced. Motivated by practical communications systems requirements, the performance measure which is used is the worst-case stopband attenuation.

  11. Experimental investigation of phase equilibria in the Zr-Cu-Ni ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Mujin; Wang, Cuiping; Yang, Shuiyuan; Shi, Zhan; Han, Jiajia; Liu, Xingjun [Xiamen Univ. (China). College of Materials and Fujian Provincial Key Lab. of Materials Genome

    2017-08-15

    The phase equilibria in the Zr-Cu-Ni ternary system are investigated combined with X-ray diffraction, electron probe micro-analysis and differential scanning calorimetry. Two isothermal sections of the Zr-Cu-Ni ternary system at 1 000 C and 1 100 C are experimentally established. Most of the binary intermetallic compounds, e.g. Zr{sub 7}Ni{sub 10}, ZrNi, ZrNi{sub 5}, Zr{sub 14}Cu{sub 51}, and Zr{sub 2}Cu{sub 9}, show a remarkable ternary solubility. A new ternary compound named τ{sub 3} (Zr{sub 31.1-30.7} . Cu{sub 28.5-40.3}Ni{sub 40.4-29.0}) is detected at 1 000 C and dissolved at 1 020 C because the nearby large liquid phase field further expands. The newly determined phase equilibria will provide important information for both thermodynamic assessment and alloy design of Zr-based metallic glass.

  12. Synthesis, structural and magnetic characterization of soft magnetic nanocrystalline ternary FeNiCo particles

    Energy Technology Data Exchange (ETDEWEB)

    Toparli, Cigdem [Department of Metallurgical & Materials Eng., Istanbul Technical University, 34469 Istanbul (Turkey); Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf (Germany); Ebin, Burçak [Department of Metallurgical & Materials Eng., Istanbul Technical University, 34469 Istanbul (Turkey); Nuclear Chemistry and Industrial Material Recycling, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, S-412 96 Gothenburg (Sweden); Gürmen, Sebahattin, E-mail: gurmen@itu.edu.tr [Department of Metallurgical & Materials Eng., Istanbul Technical University, 34469 Istanbul (Turkey)

    2017-02-01

    The present study focuses on the synthesis, microstructural and magnetic properties of ternary FeNiCo nanoparticles. Nanocrystalline ternary FeNiCo particles were synthesized via hydrogen reduction assisted ultrasonic spray pyrolysis method in single step. The effect of precursor concentration on the morphology and the size of particles was investigated. The syntheses were performed at 800 °C. Structure, morphology and magnetic properties of the as-prepared products were characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM) studies. Scherer calculation revealed that crystallite size of the ternary particles ranged between 36 and 60 nm. SEM and TEM investigations showed that the particle size was strongly influenced by the precursor concentration and Fe, Ni, Co elemental composition of individual particles was homogeneous. Finally, the soft magnetic properties of the particles were observed to be a function of their size. - Highlights: • Ternary FeNiCo alloy nanocrystalline particles were synthesized in a single step. • Cubic crystalline structure and spherical morphology was observed by XRD, SEM and TEM investigations. • The analysis of magnetic properties indicates the soft magnetic features of particles.

  13. The effects of surface processing on in-vivo corrosion of Nitinol stents in a porcine model.

    Science.gov (United States)

    Sullivan, Stacey J L; Madamba, Daniel; Sivan, Shiril; Miyashiro, Katie; Dreher, Maureen L; Trépanier, Christine; Nagaraja, Srinidhi

    2017-10-15

    A major limitation with current assessments of corrosion in metallic medical devices is the lack of correlation between in-vitro and in-vivo corrosion performance. Therefore, the objective of this study was to elucidate the relationship between pitting corrosion measured by breakdown potentials (Eb) in ASTM F2129 testing and corrosion resistance in-vivo. Four groups of Nitinol stents were manufactured using different processing methods to create unique surface properties. The stents were implanted into iliac arteries of minipigs for six months and explanted for corrosion analysis. Scanning electron microscopy and energy dispersive X-ray spectrometry analyses indicated that stents with a thick complex thermal oxide (420nm) and high corrosion resistance in-vitro (Eb=975±94mV) were free from detectable corrosion in-vivo and exhibited no changes in Ni/Ti ratio when compared to non-implanted controls. This result was also found in mechanically polished stents with a thin native oxide (4nm; Eb=767±226mV). In contrast, stents with a moderately thick thermal oxide (130nm) and low corrosion resistance in-vitro (Eb=111±63mV) possessed corrosion with associated surface microcracks in-vivo. In addition, Ni/Ti ratios in corroded regions were significantly lower compared to non-corroded adjacent areas on explanted stents. When stents were minimally processed (i.e. retained native tube oxide from the drawing process), a thick thermal oxide was present (399nm) with low in-vitro corrosion resistance (Eb=68±29mV) resulting in extensive in-vivo pitting. These findings demonstrate that functional corrosion testing combined with a detailed understanding of the surface characteristics of a Nitinol medical device can provide insight into in-vivo corrosion resistance. Nitinol is a commonly used material in the medical device industry. However, correlations between surface processing of nitinol and in-vivo corrosion has yet to be established. Elucidating the link between in

  14. Theoretical prediction and experimental confirmation of unusual ternary ordered semiconductor compounds in Sr-Pb-S system.

    Science.gov (United States)

    Hao, Shiqiang; Zhao, Li-Dong; Chen, Chang-Qiang; Dravid, Vinayak P; Kanatzidis, Mercouri G; Wolverton, Christopher M

    2014-01-29

    We examine the thermodynamics of phase separation and ordering in the ternary Ca(x)Pb(1-x)S and Sr(x)Pb(1-x)S systems by density-functional theory combined with a cluster expansion and Monte Carlo simulations. Similar to most other ternary III-V or IV-VI semiconductor alloys, we find that bulk phase separation is thermodynamically preferred for PbS-CaS. However, we predict the surprising existence of stable, ordered ternary compounds in the PbS-SrS system. These phases are previously unreported ordered rocksalt-based compounds: SrPb3S4, SrPbS2, and Sr3PbS4. The stability of these predicted ordered phases is confirmed by transmission electron microscopy observations and band gap measurements. We believe this work paves the way for a combined theory-experiment approach to decipher complex phase relations in multicomponent chalcogenide systems.

  15. Open preperitoneal mesh repair of inguinal hernias using a mesh with nitinol memory frame.

    Science.gov (United States)

    Berrevoet, F; Vanlander, A; Bontinck, J; Troisi, R I

    2013-06-01

    To prospectively evaluate the use of a continuous Nitinol containing memory frame patch during a TIPP-technique in the open repair of inguinal and femoral hernias. Over a 3-year period all consecutive adult patients that needed treatment for an inguinal or femoral hernia were treated by the TIPP repair using the Rebound Shield mesh. Intra-operatively the type and size of the hernia were evaluated according to the EHS classification, as well as the size of the mesh used. Baseline characteristics for all patients were evaluated considering age, gender, BMI and American society of Anesthesiologists score. Standard X-ray was performed to evaluate mesh position. All patients were evaluated for post-operative pain using the visual analogue scale (VAS 0-10 scale). In total 289 groin hernias were operated using a nitinol containing patch in 235 patients. The mean operating time was 38 min for unilateral hernias and 59 min for bilateral hernias. The median follow-up is 21.2 months (14-33 months) during which three patients died, unrelated to the groin hernia repair. At the time of re-evaluation 12 patients (5.0 %) complained of chronic pain, with a VAS score higher than 3 after 3 months (range 3-10). Two of these patients already had severe pain pre-operatively. A total of 3 recurrences (2.9 %) were noted with strong correlation with X-ray findings. A nitinol memory frame containing mesh is a valuable tool to achieve complete deployment of a large pore mesh in a TIPP repair for inguinal hernias with acceptable morbidity and a low recurrence rate.

  16. Collateral damage to the ureter and Nitinol stone baskets during thulium fiber laser lithotripsy.

    Science.gov (United States)

    Wilson, Christopher R; Hardy, Luke A; Irby, Pierce B; Fried, Nathaniel M

    2015-07-01

    The experimental Thulium fiber laser (TFL) is currently being studied as a potential alternative lithotripter to the clinical gold standard Holmium:YAG laser. Safety studies characterizing undesirable Holmium:YAG laser-induced damage to ureter tissue and stone baskets have been previously reported. Similarly, this study characterizes TFL induced ureter and stone basket damage. A TFL beam with energy of 35 mJ per pulse, pulse duration of 500 µs, and variable pulse rates of 50-500 Hz, was delivered through 100-µm-core optical fibers, to either porcine ureter wall, in vitro, or a standard 1.9-Fr Nitinol stone basket wire. Ureter perforation times were measured and gross, histological, and optical coherence tomography images of the ablation area were acquired. Stone basket damage was graded as a function of pulse rate, number of pulses, and working distance. TFL operation at 150, 300, and 500 Hz produced mean ureter perforation times of 7.9, 3.8, and 1.8 seconds, respectively. Collateral damage widths averaged 510, 370, and 310 µm. Nitinol wire damage decreased with working distance and was non-existent at distances greater than 1.0 mm. In contact mode, 500 pulses delivered at pulse rates ≥300 Hz (≤1.5 seconds) were sufficient to cut Nitinol wires. The TFL, operated in low pulse energy and high pulse rate mode, may provide a greater safety margin than the standard Holmium:YAG laser for lithotripsy, as evidenced by longer TFL ureter perforation times and shorter non-contact working distances for stone basket damage than previously reported with Holmium:YAG laser. © 2015 Wiley Periodicals, Inc.

  17. Relationship Between Primary Patency and Lesion Length Following Bare Nitinol Stent Placement for Femoropopliteal Disease.

    Science.gov (United States)

    Soga, Yoshimitsu; Takahara, Mitsuyoshi; Iida, Osamu; Suzuki, Kenji; Hirano, Keisuke; Kawasaki, Daizo; Shintani, Yoshiaki; Yamaoka, Terutoshi; Ando, Kenji

    2015-12-01

    To evaluate the relationship between 1-year primary patency and lesion length in patients with femoropopliteal disease treated with bare nitinol stents. The study was a retrospective analysis of a prospectively maintained multicenter database. Between January 2004 and December 2011, 1047 consecutive patients (mean age 72 years; 765 men) underwent femoropopliteal stenting with nitinol stents in 1373 limbs. The mean vessel diameter was 5.3±0.7 mm and the mean lesion length was 142±75 mm. One-year follow-up data were collected and analyzed to ascertain which lesion length would be expected to demonstrate a 1-year primary patency above the established 66% objective performance goal (OPG). The lower limit of the 95% confidence interval (CI) for the unadjusted 1-year primary patency was >66% when the lesion length was ≤243 mm. After adjustment of the covariates to match those of the OPG-derived population, the 1-year primary patency decreased linearly with longer lesion length. The 1-year primary patency was 83.2% (95% CI 79.8% to 86.1%) for a 100-mm lesion length, 76.4% (95% CI 71.7% to 80.5%) for a 200-mm lesion length, and 70.7% (95% CI 62.4% to 77.7%) for a 300-mm lesion length. The maximum lesion length providing a 1-year primary patency significantly greater than 66% was calculated to be 263 mm. The 1-year primary patency of femoropopliteal lesions treated with bare nitinol stents decreased linearly with longer lesion length. The maximum lesion length providing a higher patency rate than the OPG of 66% was ~25 cm. © The Author(s) 2015.

  18. Ternary networks reliability and Monte Carlo

    CERN Document Server

    Gertsbakh, Ilya; Vaisman, Radislav

    2014-01-01

    Ternary means “based on three”. This book deals with reliability investigations of  networks whose components subject to failures can be in three states –up, down and middle (mid), contrary to traditionally considered networks  having only binary (up/down) components. Extending binary case to ternary allows to consider more realistic and flexible models for communication, flow and supply networks.

  19. The Effect of Various Quenchants on the Hardness and Microstructure of 60-NITINOL

    Science.gov (United States)

    Thomas, Fransua

    2015-01-01

    The effect of various quenching media on the hardness and microstructure of 60 NITINOL (60 NiTi) were evaluated. Specimens of 60 NiTi were heat treated in air at 1000 degC for 30 min or 2 hr, then quench cooled by one of seven different methods. The microstructure and hardness of this material was examined post heat treatment. The results indicated that the quench method had little effect on the resulting hardness and microstructure of 60 NiTi.

  20. On phase transformation models for thermo-mechanically coupled response of Nitinol

    KAUST Repository

    Sengupta, Arkaprabha

    2011-03-31

    Fully coupled thermomechanical models for Nitinol at the grain level are developed in this work to capture the inter-dependence between deformation and temperature under non-isothermal conditions. The martensite transformation equations are solved using a novel algorithm which imposes all relevant constraints on the volume fractions. The numerical implementation of the resulting models within the finite element method is effected by the monolithic solution of the momentum and energy equations. Validation of the models is achieved by means of thin-tube experiments at different strain rates. © 2011 Springer-Verlag.

  1. Internal oxidation of laminated ternary Ru-Ta-Zr coatings

    Science.gov (United States)

    Chen, Yung-I.; Lu, Tso-Shen

    2015-10-01

    Researchers have observed the internal oxidation phenomenon in binary alloy coatings when developing refractory alloy coatings for protective purposes by conducting annealing at high temperatures and in oxygen-containing atmospheres. The coatings were assembled using cyclical gradient concentration deposition during cosputtering by employing a substrate holder rotating at a slow speed. The internally oxidized zone demonstrated a laminated structure, comprising alternating oxygen-rich and oxygen-deficient layers stacked in a general orientation. In the current study, Ru-Ta-Zr coatings were prepared with various stacking sequences during cosputtering. The Ru-Ta-Zr coatings were annealed at 600 °C in an atmosphere continuously purged with 1% O2-99% Ar mixed gas for 30 min. A transmission electron microscope was used to examine the periods of the laminated layers and crystallinity of the annealed coatings. Depth profiles produced using an Auger electron spectroscope and X-ray photoelectron spectroscope were used to certify the periodic variation of the related constituents and chemical states of the elements, respectively. The results indicate that the internally oxidized ternary coatings are stacked of Ru-, Ta2O5-, and ZrO2-dominant sublayers and that the stacking sequences of the sublayers affect the crystalline structure of the coatings. Zr is oxidized preferentially in the Ru-Ta-Zr coatings, increasing the surface hardness of the oxidized coatings.

  2. Design and Testing of a Minimally Invasive Blood Clot Removal Device ConstructedWith Elements of Superelastic Nitinol

    Science.gov (United States)

    Puffer, Andrew J.

    Many vascular system problems stem from insufficient blood return flow to the heart. One of the main causes is a blockage within veins or arteries known as a blood clot, or thrombus. This can occur after trauma, surgery, or other phenomenological reasons. Each year in the U.S. more than 175,000 bypass procedures and more than 160,000 amputations resulting from peripheral vessel disease are performed. Clinical data indicates that clot removal devices and procedures can reduce the need for an amputation by 80 percent. Percutaneous thrombectomy refers to the removal of thrombus using catheter based non-surgical methods. The ultimate goal of any modality to treat these conditions of the arterial or venous system is to restore patency, quickly, safely, and cost effectively. Catheter directed thrombectomy and thrombolysis is less traumatic and avoids the morbidity and mortality associated with conventional surgical technique. As a result, there has been a push recently for the use of percutaneous mechanical thrombectomy (PMT) devices. However, all devices have their own set of drawbacks: distal embolization, vessel wall trauma, hemolysis, to name a few. Ongoing efforts have been made to create a prototype thrombectomy device that uses elements of superelastic nitinol (a type of shape memory alloy), that seeks to address some of the drawbacks of current devices. The prototype was designed and tested in a simulated human circulatory system along side a commercially available device (The DiverCE Clot Extraction Catheter). The test evaluated how well the devices minimized distal embolization of a human blood clot created in vitro.. Results of the testing showed that the prototype device created significantly less embolization when compared to the DiverCE particles greater than 102mum (p = 0.0332). Means were statistically not different for particles between 25mum and 102mum (p = 0.2454), and particles between 5mum and 25mum (p = 0.6524). In addition the prototype was shown

  3. Influence of temperature of the short-period heat treatment on mechanical properties of the NiTi alloy

    Directory of Open Access Journals (Sweden)

    Jaroslav Čapek

    2014-01-01

    Full Text Available The equiatomic alloy of nickel and titanium, known as nitinol, possesses unique properties such as superelasticity, pseudoplasticity, shape memory, while maintaining good corrosion resistance and sufficient biocompatibility. Therefore it is used for production of various devices including surgery implants. Heat treatment of nickel-rich NiTi alloys can result in precipitation of nickel-rich phases, which strongly influence tensile and fatigue behaviour of the material.In this work we have studied influence of short-period heat treatment on tensile behaviour and fatigue life of the NiTi (50.9 at. % Ni wire intended for fabrication of surgery stents.

  4. Undercooling and demixing of copper-based alloys

    DEFF Research Database (Denmark)

    Kolbe, M.; Brillo, J.; Egry, I.

    2006-01-01

    Since the beginning of materials science research under microgravity conditions immiscible alloys have been an interesting subject. New possibilities to investigate such systems are offered by containerless processing techniques. Of particular interest is the ternary system Cu-Fe-Co, and its...

  5. Reduction in thermal conductivity of Bi–Te alloys through grain ...

    Indian Academy of Sciences (India)

    Ternary alloys of thermoelectric materials Bi–Sb–Te and Bi–Se–Te of molecular formula, Bi0.5Sb1.5Te3 ( type) and Bi0.36Se0.064Te0.576 ( type), were prepared by mechanical alloying method. The preparation of materials by mechanical alloying method has effectively reduced the thermal conductivity by generating a ...

  6. Growth and characterization of III-N ternary thin films by plasma assisted atomic layer epitaxy at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Nepal, Neeraj; Anderson, Virginia R.; Hite, Jennifer K.; Eddy, Charles R.

    2015-08-31

    We report the growth and characterization of III-nitride ternary thin films (Al{sub x}Ga{sub 1−x}N, In{sub x}Al{sub 1−x}N and In{sub x}Ga{sub 1−x}N) at ≤ 500 °C by plasma assisted atomic layer epitaxy (PA-ALE) over a wide stoichiometric range including the range where phase separation has been an issue for films grown by molecular beam epitaxy and metal organic chemical vapor deposition. The composition of these ternaries was intentionally varied through alterations in the cycle ratios of the III-nitride binary layers (AlN, GaN, and InN). By this digital alloy growth method, we are able to grow III-nitride ternaries by PA-ALE over nearly the entire stoichiometry range including in the spinodal decomposition region (x = 15–85%). These early efforts suggest great promise of PA-ALE at low temperatures for addressing miscibility gap challenges encountered with conventional growth methods and realizing high performance optoelectronic and electronic devices involving ternary/binary heterojunctions, which are not currently possible. - Highlights: • III-N ternaries grown at ≤ 500 °C by plasma assisted atomic layer epitaxy • Growth of InGaN and AlInN in the spinodal decomposition region (15–85%) • Epitaxial, smooth and uniform III-N film growth at low temperatures.

  7. Endoscopic placement of multiple artificial chordae with robotic assistance and nitinol clip fixation.

    Science.gov (United States)

    Smith, J Michael; Stein, Hubert

    2008-03-01

    A totally endoscopic method of placing multiple premeasured artificial chordae with the assistance of the da Vinci surgical system (Intuitive Surgical Inc, Sunnyvale, Calif) and V60 U-clip devices (Medtronic Inc, Minneapolis, Minn) was evaluated. Totally endoscopic placement of multiple artificial chordae with robotic assistance and nitinol clips was performed in 30 patients. After subvalvular exposure with a robotically controlled Atrial Retractor (Intuitive Surgical Inc), artificial chordae constructed of 4-0 polytetrafluoroethylene (Gore-Tex; WL Gore & Associates Inc, Flagstaff, Ariz) were secured to the prolapsing leaflet edge with V60 U-clips. Transesophageal echocardiography to assess successful repair was performed. Repairs of the anterior leaflet, the posterior leaflet, and combinations of both were performed. Crossclamp and cardiopulmonary bypass times were in the range of 78.63 +/- 17.03 minutes and 118.17 +/- 22.55 minutes, respectively. Transesophageal echocardiography showed grade 0 to less than grade 1 mitral regurgitation postoperatively. All patients had an uneventful recovery phase and were discharged within 5 days. Endoscopic placement of premeasured artificial neochordae is greatly facilitated by applying robotic assistance and using nitinol clips for chordae fixation. The endoscopic robotic technique provides excellent functional and clinical outcomes.

  8. Short-term hearing results after primary stapedotomy with nitinol and teflon-platinum prostheses for otosclerosis.

    Science.gov (United States)

    Gouveris, Haralampos; Tóth, Miklós; Koutsimpelas, Dimitrios; Schmidtmann, Irene; Mann, Wolf J

    2013-08-01

    The aim of this study is to determine differences in postoperative air-bone gap (ABG) after placement of teflon-platinum or nitinol middle ear prostheses in primary stapedotomy patients with otosclerosis. Thirty otosclerosis patients (24 female, 6 male; age 10-61 years) with primary stapedotomy were studied prospectively. Before and after surgery, the mean and standard deviations of the ABG were measured at eight frequencies (0.25-4 kHz). Patients were randomized into one of two groups receiving either teflon-platinum or nitinol prostheses. Hearing results were assessed 1 year after surgery. To assess the joint influence of treatment and frequency on ABG reduction, a linear mixed model was used (significance level was p = 5%). The Tukey-Kramer method was used to adjust for multiple comparisons. Significant differences were found between treatment groups (p Teflon group had a larger reduction of conductive components, on average 8.0 dB more reduction, than patients in the nitinol group. However, after adjusting for multiple comparisons, we could not identify a single frequency with a significant difference in reduction of conductive components. Use of the teflon-platinum prosthesis results in statistically non-significant better ABG closure at 0.25-4 kHz 1 year postoperatively than the use of the nitinol prosthesis.

  9. Effect of biologically active coating on biocompatibility of Nitinol devices designed for the closure of intra-atrial communications

    NARCIS (Netherlands)

    Kong, XQ; Grabitz, RG; van Oeveren, W; Klee, D; van Kooten, TG; Freudenthal, F; Qing, M; von Bernuth, G; Seghaye, MC

    Anti-thrombogenicity and rapid endothelialisation are prerequisites for the use of closure devices of intra-atrial communications in order to reduce the risk of cerebral embolism. The purpose of this study was therefore to assess the effect of bioactive coatings on biocompatibility of Nitinol coils

  10. Porous surface structure of biocompatible implants and tissue scaffolds base of titanium and nitinol synthesized SLS/M methods

    Science.gov (United States)

    Shishkovsky, I.; Sherbakov, V.; Petriv, A.; Kuznetsov, M.; Morozov, Yu.; Volova, L.; Barikov, I.; Fakeev, S.

    2007-06-01

    The objectives of these researches were to investigate the technical fundamentals of synthesizing high-strength biocompatible medical implants and tissue scaffolds made from nitinol or titanium using of Selective Laser Sintering/Melting (SLS/M). In particular, we had been identify the processing parameters and procedures necessary to successfully laser synthesize multi-material and functionally graded implants: the physical and mechanical properties, microstructure, and corrosion behavior of the resulting structures; the shape memory effect in porous layered nitinol structures made using laser synthesis. The comparative morphological and histological results of Selective Laser Sintering of porous titanium and nitinol implants are presented. Studies are conducted also on primary cultures of dermal fibroblasts and mesenchymal stromal human cells of the 4-18 passages. The principle possibility of long cultivating a bone marrow on the porous carrier-incubator from NiTi and titanium in vitro was determined. Sufficient understanding of laser synthesized titanium and nitinol structures to determine their suitability for future use as implants, resulting in superior tissue to implant fixation and minimally invasive surgical procedures, was developed.

  11. Understanding Organic Film Behavior on Alloy and Metal Oxides

    Science.gov (United States)

    Raman, Aparna; Quiñones, Rosalynn; Barriger, Lisa; Eastman, Rachel; Parsi, Arash

    2010-01-01

    Native oxide surfaces of stainless steel 316L and Nitinol alloys and their constituent metal oxides namely, nickel, chromium, molybdenum, manganese, iron and titanium were modified with long chain organic acids to better understand organic film formation. The adhesion and stability of films of octadecylphosphonic acid, octadecylhydroxamic acid, octadecylcarboxylic acid and octadecylsulfonic acid on these substrates was examined in this study. The films formed on these surfaces were analyzed by diffuse reflectance infrared Fourier transform spectroscopy, contact angle goniometry, atomic force microscopy and matrix assisted laser desorption ionization mass spectrometry. The effect of the acidity of the organic moiety and substrate composition on the film characteristics and stability is discussed. Interestingly, on the alloy surfaces, the presence of less reactive metal sites does not inhibit film formation. PMID:20039608

  12. Pulse reversal plating of nickel alloys

    DEFF Research Database (Denmark)

    Tang, Peter Torben

    2007-01-01

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

  13. Study on La–Mg based ternary system for hydrogen storage

    Energy Technology Data Exchange (ETDEWEB)

    Capurso, Giovanni, E-mail: giovanni.capurso@gmail.com [Dipartimento di Ingegneria Industriale, Università di Padova, via Marzolo 9, 35131 Padova (Italy); Naik, Mehraj-ud-din; Lo Russo, Sergio [Dipartimento di Fisica e Astronomia “Galileo Galilei”, Università di Padova, via Marzolo 8, 35131 Padova (Italy); Maddalena, Amedeo [Dipartimento di Ingegneria Industriale, Università di Padova, via Marzolo 9, 35131 Padova (Italy); Saccone, Adriana; Gastaldo, Federica; De Negri, Serena [Dipartimento di Chimica e Chimica Industriale, Università di Genova, via Dodecaneso 31, 16146 Genova (Italy)

    2013-12-15

    Highlights: ► Explorative study in the Mg-rich corner of the La–Pd–Mg ternary system. ► The studied alloys lay on the La{sub 2}(Mg{sub 1−x}Pd{sub x}){sub 17} compositional line. ► Higher Pd content results in lower H{sub 2} capacity, but higher equilibrium pressures. ► The highest absorbed hydrogen quantity is 4.8 wt% at 2 MPa and 310 °C. -- Abstract: An explorative study on the hydriding/dehydriding characteristics of the La{sub 2}(Mg,Pd){sub 17} ternary alloy, with different Pd content, is presented. All the samples were prepared by induction melting of the selected elements, characterized with scanning electron microscopy and X-ray powder diffraction, to detect present phases, and subsequently milled with a high-energy shaker apparatus. The hydrogen reaction kinetics and thermodynamics properties have been investigated by means of a volumetric Sievert’s apparatus. The measured H{sub 2} gravimetric capacity of the alloy varied with the Pd content, being the highest for the sample without Pd (>4.5 wt%). A possible correlation between the constituent phases individuated with microanalysis and the variation in the hydrogenation behaviour is proposed.

  14. Insight of magnesium alloys and composites for orthopedic implant applications – a review

    Directory of Open Access Journals (Sweden)

    R Radha

    2017-09-01

    Full Text Available Magnesium (Mg and its alloys have been widely researched for orthopedic applications recently. Mg alloys have stupendous advantages over the commercially available stainless steel, Co-Cr-Ni alloy and titanium implants. Till date, extensive mechanical, in-vitro and in-vivo studies have been done to improve the biomedical performance of Mg alloys through alloying, processing conditions, surface modification etc. This review comprehensively describes the strategies for improving the mechanical and degradation performance of Mg alloys through properly tailoring the composition of alloying elements, reinforcements and processing techniques. It also highlights the status and progress of research in to (i the selection of nutrient elements for alloying, reinforcement and its effects (ii type of Mg alloy system (binary, ternary and quaternary and composites (iii grain refinement for strengthening through severe plastic deformation techniques. Furthermore it also emphasizes on the importance of Mg composites with regard to hard tissue applications.

  15. Pd-Cu-M (M = Y, Ti, Zr, V, Nb, and Ni) Alloys for the Hydrogen Separation Membrane.

    Science.gov (United States)

    Nayebossadri, Shahrouz; Speight, John D; Book, David

    2017-01-25

    Self-supported fcc Pd-Cu-M (M = Y, Ti, Zr, V, Nb, and Ni) alloys were studied as potential hydrogen purification membranes. The effects of small additions (1-2.6 at. %) of these elements on the structure, hydrogen solubility, diffusivity, and permeability were examined. Structural analyses by X-ray diffraction (XRD) showed the fcc phase for all alloys with induced textures from cold rolling. Heat treatment at 650 °C for 96 h led to the reorientation in all alloys except the Pd-Cu-Zr alloy, exhibiting the possibility to enhance the structural stability by Zr addition. Hydrogen solubility was almost doubled in the ternary alloys containing Y and Zr compared to Pd65.1Cu34.9 alloy at 300 °C. It was noted that hydrogen diffusivity is decreased upon additions of these elements compared to the Pd65.1Cu34.9 alloy, with the Pd-Cu-Zr alloy showing the lowest hydrogen diffusivity. However, the comparable hydrogen permeability of the Pd-Cu-Zr alloy with the corresponding binary alloy, as well as its highest hydrogen permeability among the studied ternary alloys at temperatures higher than 300 °C, suggested that hydrogen permeation of these alloys within the fcc phase is mainly dominated by hydrogen solubility. Hydrogen flux variations of all ternary alloys were studied and compared with the Pd65.1Cu34.9 alloy under 1000 ppm of H2S + H2 feed gas. Pd-Cu-Zr alloy showed superior resistance to the sulfur poisoning probably due to the less favorable H2S-surface interaction and more importantly slower rate of bulk sulfidation as a result of improved structural stability upon Zr addition. Therefore, Pd-Cu-Zr alloys may offer new potential hydrogen purification membranes with improved chemical stability and hydrogen permeation compared to the binary fcc Pd-Cu alloys.

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

    DEFF Research Database (Denmark)

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

    2010-01-01

    of the Au–Sn binary system were explored in this work. Furthermore, the effects of thermal aging on the microstructure and microhardness of these promising Au–Sn based ternary alloys were investigated. For this purpose, the candidate alloys were aged at a lower temperature, 150°C for up to 1week...

  17. 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.

  18. Heat storage in alloy transformations. Final report

    Energy Technology Data Exchange (ETDEWEB)

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

    1981-03-01

    A study conducted to determine the feasibility of using metal alloys as thermal energy storage media is described. The study had the following major elements: (1) the identification of congruently transforming alloys and thermochemical property measurements, (2) the development of a precise and convenient method for measuring volume change during phase transformation and thermal expansion coefficients, (3) the development of a numerical modeling routine for calculating heat flow in cylindrical heat exchangers containing phase-change materials, and (4) the identification of materials that could be used to contain the metal alloys. The elements selected as candidate media were limited to aluminum, copper, magnesium, silicon, zinc, calcium, and phosphorus on the basis of low cost and latent heat of transformation. Several new eutectic alloys and ternary intermetallic phases have been determined. A new 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 that are 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. Candidate materials were evaluated to determine suitable materials for containment of the metal alloys. Graphite was used to contain the alloys during the volume change measurements. Silicon carbide has been identified as a promising containment material and surface-coated iron alloys were considered.

  19. Shape Memory Alloys (Part II: Classification, Production and Application

    Directory of Open Access Journals (Sweden)

    I. Ivanic

    2014-09-01

    Full Text Available Shape memory alloys (SMAs have been extensively investigated because of their unique shape memory behaviour, i.e. their ability to recover their original shape they had before deformation. Shape memory effect is related to the thermoelastic martensitic transformation. Austenite to martensite phase transformation can be obtained by mechanical (loading and thermal methods (heating and cooling. Depending on thermomechanical conditions, SMAs demonstrate several thermomechanical phenomena, such as pseudoelasticity, superelasticity, shape memory effect (one-way and two-way and rubber-like behaviour. Numerous alloys show shape memory effect (NiTi-based alloys, Cu-based alloys, Fe-based alloys etc.. Nitinol (NiTi is the most popular and the most commonly used SMA due to its superior thermomechanical and thermoelectrical properties. NiTi alloys have greater shape memory strain and excellent corrosion resistance compared to Cu – based alloys. However, they are very costly. On the other hand, copper-based alloys (CuZn and CuAl based alloys are much less expensive, easier to manufacture and have a wider range of potential transformation temperatures. The characteristic transformation temperatures of martensitic transformation of CuAlNi alloys can lie between −200 and 200 °C, and these temperatures depend on Al and Ni content. Among the Cu – based SMAs, the most frequently applied are CuZnAl and CuAlNi alloys. Although CuZnAl alloys with better mechanical properties are the most popular among the Cu-based SMAs, they lack sufficient thermal stability, while CuAlNi shape memory alloys, in spite of their better thermal stability, have found only limited applications due to insufficient formability owing to the brittle γ2 precipitates. The most important disadvantage of polycrystalline CuAlNi alloys is a small reversible deformation (one-way shape memory effect: up to 4 %; two-way shape memory effect: only approximately 1.5 % due to intergranular

  20. Ternary interaction parameters in calphad solution models

    Energy Technology Data Exchange (ETDEWEB)

    Eleno, Luiz T.F., E-mail: luizeleno@usp.br [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Fisica; Schön, Claudio G., E-mail: schoen@usp.br [Universidade de Sao Paulo (USP), SP (Brazil). Computational Materials Science Laboratory. Department of Metallurgical and Materials Engineering

    2014-07-01

    For random, diluted, multicomponent solutions, the excess chemical potentials can be expanded in power series of the composition, with coefficients that are pressure- and temperature-dependent. For a binary system, this approach is equivalent to using polynomial truncated expansions, such as the Redlich-Kister series for describing integral thermodynamic quantities. For ternary systems, an equivalent expansion of the excess chemical potentials clearly justifies the inclusion of ternary interaction parameters, which arise naturally in the form of correction terms in higher-order power expansions. To demonstrate this, we carry out truncated polynomial expansions of the excess chemical potential up to the sixth power of the composition variables. (author)

  1. Ternary carbon composite films for supercapacitor applications

    Science.gov (United States)

    Tran, Minh-Hai; Jeong, Hae Kyung

    2017-09-01

    A simple, binder-free, method of making supercapacitor electrodes is introduced, based on modification of activated carbon with graphite oxide and carbon nanotubes. The three carbon precursors of different morphologies support each other to provide outstanding electrochemical performance, such as high capacitance and high energy density. The ternary carbon composite shows six times higher specific capacitance compared to that of activated carbon itself with high retention. The excellent electrochemical properties of the ternary composite attribute to the high surface area of 1933 m2 g-1 and low equivalent series resistance of 2 Ω, demonstrating that it improve the electrochemical performance for supercapacitor applications.

  2. Effect of alloying on elastic properties of ZrN based transition metal nitride alloys

    KAUST Repository

    Kanoun, Mohammed

    2014-09-01

    We report the effect of composition and metal sublattice substitutional element on the structural, elastic and electronic properties of ternary transition metal nitrides Zr1-xMxN with M=Al, Ti, Hf, V, Nb, W and Mo. The analysis of the elastic constants, bulk modulus, shear modulus, Young\\'s modulus, and Poisson\\'s ratio provides insights regarding the mechanical behavior of Zr1-xMxN. We predict that ternary alloys are more ductile compared to their parent binary compounds. The revealed trend in the mechanical behavior might help for experimentalists on the ability of tuning the mechanical properties during the alloying process by varying the concentration of the transition metal. © 2014 Elsevier B.V.

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

    DEFF Research Database (Denmark)

    Tang, Peter Torben

    2001-01-01

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

  4. Nb-Based Nb-Al-Fe Alloys: Solidification Behavior and High-Temperature Phase Equilibria

    Science.gov (United States)

    Stein, Frank; Philips, Noah

    2017-09-01

    High-melting Nb-based alloys hold significant promise for the development of novel high-temperature materials for structural applications. In order to understand the effect of alloying elements Al and Fe, the Nb-rich part of the ternary Nb-Al-Fe system was investigated. A series of Nb-rich ternary alloys were synthesized from high-purity Nb, Al, and Fe metals by arc melting. Solidification paths were identified and the liquidus surface of the Nb corner of the ternary system was established by analysis of the as-melted microstructures and thermal analysis. Complementary analysis of heat-treated samples yielded isothermal sections at 1723 K and 1873 K (1450 °C and 1600 °C).

  5. Effect of scandium addition on the microstructure, mechanical and wear properties of the spray formed hypereutectic aluminum–silicon alloys

    Energy Technology Data Exchange (ETDEWEB)

    Raghukiran, Nadimpalli; Kumar, Ravi, E-mail: nvrk@iitm.ac.in

    2015-08-12

    Hypereutectic Al–x%Si–0.8Sc alloys (x=13, 16, 19 and 22 wt%) were produced by spray forming. The microstructures of all the alloys exhibited very fine silicon phase with average size of about 5–10 µm irrespective of the silicon content of the alloy. Transmission electron microscopy revealed the presence of a nano-scale scandium rich phase, identified as AlSi{sub 2}Sc{sub 2} (V-phase) uniformly distributed in the alloy. The presence of V-phase resulted in higher matrix hardness (1.34 GPa) in contrast to 1.04 GPa observed in the case of binary Al–Si alloys by nanoindentation. Isothermal heat treatment at 375 °C revealed insignificant coarsening of silicon phase in both binary and ternary alloys. The Al–x%Si–0.8Sc alloys exhibited higher flow stress and tensile strength in contrast to their binary alloy counterparts which was attributed to the bi-modal size distribution of the strengthening phases in the form of nano-scale V-phase and sub-micron to 10 µm size silicon particles. The pin-on-disk wear tests exhibited appreciable improvement in the wear performance of the relatively low-silicon content ternary alloys over their binary counterparts while the high-silicon content binary and ternary alloys exhibited no much difference in the wear performance.

  6. Cytotoxicity of Ni from Surface-Treated Porous Nitinol (PNT) on Osteoblast Cells

    Science.gov (United States)

    Pulletikurthi, C.; Munroe, N.; Gill, P.; Pandya, S.; Persaud, D.; Haider, W.; Iyer, K.; McGoron, A.

    2011-07-01

    The leaching of nickel from the surface of porous Nitinol (PNT) is mainly dependent on its surface characteristics, which can be controlled by appropriate surface treatments. In this investigation, PNT was subjected to two surface treatments, namely, water-boiling and dry-heating passivations. Phosphate buffer saline (PBS) solutions obtained from cyclic potentiodynamic polarization tests on PNT were employed to assess the cytotoxicity of Ni contained therein on osteoblast cells by Sulforhodamine B (SRB) assay. In addition, similar concentrations of Ni were added exogenously to cell culture media to determine cytotoxic effects on osteoblast cells. The morphologies of the untreated and the surface-treated PNTs were examined using SEM and AFM. Furthermore, growth of human osteoblast cells was observed on the PNT surfaces.

  7. Ternary-fragmentation-driving potential energies of 252Cf

    Science.gov (United States)

    Karthikraj, C.; Ren, Zhongzhou

    2017-12-01

    Within the framework of a simple macroscopic model, the ternary-fragmentation-driving potential energies of 252Cf are studied. In this work, all possible ternary-fragment combinations of 252Cf are generated by the use of atomic mass evaluation-2016 (AME2016) data and these combinations are minimized by using a two-dimensional minimization approach. This minimization process can be done in two ways: (i) with respect to proton numbers (Z1, Z2, Z3) and (ii) with respect to neutron numbers (N1, N2, N3) of the ternary fragments. In this paper, the driving potential energies for the ternary breakup of 252Cf are presented for both the spherical and deformed as well as the proton-minimized and neutron-minimized ternary fragments. From the proton-minimized spherical ternary fragments, we have obtained different possible ternary configurations with a minimum driving potential, in particular, the experimental expectation of Sn + Ni + Ca ternary fragmentation. However, the neutron-minimized ternary fragments exhibit a driving potential minimum in the true-ternary-fission (TTF) region as well. Further, the Q -value energy systematics of the neutron-minimized ternary fragments show larger values for the TTF fragments. From this, we have concluded that the TTF region fragments with the least driving potential and high Q values have a strong possibility in the ternary fragmentation of 252Cf. Further, the role of ground-state deformations (β2, β3, β4, and β6) in the ternary breakup of 252Cf is also studied. The deformed ternary fragmentation, which involves Z3=12 -19 fragments, possesses the driving potential minimum due to the larger oblate deformations. We also found that the ground-state deformations, particularly β2, strongly influence the driving potential energies and play a major role in determining the most probable fragment combinations in the ternary breakup of 252Cf.

  8. OPTIMIZATION RESULTS OF TEMPOROMANDIBULAR REPARATIVE REGENERATION BY NITINOL MATRICES (Experimental study

    Directory of Open Access Journals (Sweden)

    N. M. Dyuryagin

    2014-01-01

    Full Text Available Aim. Through the experiments on animals, mandibular fragments reparative regeneration and osteohistogenesis in the post-resection period using different ways of their optimization by artifi cial nitinol matrices were investigated.Materials and methods. Rabbits (two groups were subjected to similar resections of mandibular right branch fragments with articular head exarticulation. In the fi rst group (n = 10 extrafocal matrix structures placement option towards regeneration foci (sagittal dislocation was used, in the second one (n = 10 intrafocal matrix bone and periosteum nitinol constructions placement option was used.Results. In the fi rst group, the following reconstructive results were received: organ-like osteogenic regenerates fully displaced mandibular defects in 12 months. In the second group reconstructive results were the following: tissue-engineered composites fully displaced mandibular defects in 3 months. Biological, biometric, radiological, histological, immunohistochemical, morphometric, statistical methods were used to evaluate the results.Conclusion. Reparative regeneration and osteohistogenesis at extrafocal placement of artifi cial matrix structures are able to reconstruct independently mandibular fragments due to natural regeneration. Reparative regeneration and osteohistogenesis at intrafocal placement of artifi cial matrix structures are able to reconstruct independently mandibular fragments due to bone and periosteum tissue-engineered composites forming. Four-fold advantage of mandibular reconstruction dynamics by tissue-engineered composites being equal in functional effi ciency with natural regeneration results testifi es to their availability for usage in clinical practice.

  9. Effect of the third element on the structure of liquid Mg65Cu25Y10 alloy

    Science.gov (United States)

    Liu, Dan; Zhu, Xun Ming; Qin, Jing Yu; Duan, Jun Peng; Wang, Ai Min; Gu, Ting Kun

    2016-08-01

    The liquid structures of Mg65Cu25Y10 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 Mg65Cu25Y10 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 Mg65Cu25Y10 liquid alloy.

  10. Self-triggered coordination with ternary controllers

    NARCIS (Netherlands)

    De Persis, Claudio; Frasca, Paolo

    2012-01-01

    This paper regards coordination of networked systems with ternary controllers. We develop a hybrid coordination system which implements a self-triggered communication policy, based on polling the neighbors upon need. We prove that the proposed scheme ensures finite-time convergence to a neighborhood

  11. Ternary Dynamic Images In Robotic Smooth Pursuit

    Science.gov (United States)

    Morasso, Pietro; Tagliasco, Vincenzo

    1984-02-01

    Early stages of visuo-motor interaction are considered with regard to dynamic scene analysis. Target fixation and tracking is distinguished from target visual analysis. The notion of target specification is elaborated upon. The use of ternary dynamic images is shown as an example of target tracking.

  12. Spray Forming of NiTi and NiTiPd Shape-Memory Alloys

    Science.gov (United States)

    Mabe, James; Ruggeri, Robert; Noebe, Ronald

    2008-01-01

    In the work to be presented, vacuum plasma spray forming has been used as a process to deposit and consolidate prealloyed NiTi and NiTiPd powders into near net shape actuators. Testing showed that excellent shape memory behavior could be developed in the deposited materials and the investigation proved that VPS forming could be a means to directly form a wide range of shape memory alloy components. The results of DSC characterization and actual actuation test results will be presented demonstrating the behavior of a Nitinol 55 alloy and a higher transition temperature NiTiPd alloy in the form of torque tube actuators that could be used in aircraft and aerospace controls.

  13. NiTi Alloys: New Materials that enable Shockproof, Corrosion Immune Bearings

    Science.gov (United States)

    DellaCorte, Christopher

    2017-01-01

    Though steel is the dominant material of choice for mechanical components (bearings and gears) it has intrinsic limitations related to corrosion and plastic deformation. In contrast, dimensionally stable nickel-rich Ni-Ti alloys, such as Nitinol 60, are intrinsically rustproof and can withstand high contact loads without damage (denting). Over the last decade, focused RD to exploit these alloys for new applications has revealed the science behind NiTi's remarkable properties. In this presentation, the state-of-the-art of nickel-rich NiTi alloys will be introduced along with a discussion of how NASA is adopting this new technology inside the space station water recycling system as a pathfinder for more down-to-earth tribological challenges.

  14. Experimental investigation of phase equilibria in the Co-Ni-Zr ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xingjun; Yang, Shuiyuan; Yu, Wenjie; Wang, Cuiping [Xiamen Univ. (China). Fujian Key Laboratory of Materials Genome; Xiong, Huaping; Cheng, Yaoyong; Wu, Xin [Beijing Institute of Aeronautical Materials (China). Div. of Welding and Forging

    2016-10-15

    The phase equilibria of the Co-Ni-Zr ternary system at 1 000 C, 1 100 C and 1 200 C were experimentally investigated by means of back-scattered electron imaging, electron probe microanalysis and X-ray diffraction on the equilibrated ternary alloys. In this study, no ternary compound is found. The (αCo, Ni) phase region extends from the Ni-rich corner to the Co-rich corner with small solubility of Zr at three sections. At 1 000 C and 1 100 C, Ni{sub 5}Zr, Co{sub 2}Zr and Ni{sub 10}Zr{sub 7} phases have large solid solution ranges, but Ni{sub 10}Zr{sub 7} phase disappears at 1 200 C. The Ni{sub 7}Zr{sub 2}, NiZr, Co{sub 11}Zr{sub 2}, Co{sub 23}Zr{sub 6} and CoZr phases exhibit nearly linear compounds in the studied sections, and have large composition ranges. Additionally, some differences in phase relationship exist among the above three isothermal sections.

  15. The analysis of fuel constituent redistribution for ternary metallic fuel slug

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byoung Oon; Lee, Dong Uk; Kim, Young Kyun; Chang, Jin Wook; Lee, Ki Bok; Kim, Young Il

    2004-02-01

    U-TRU-Zr metallic alloy is being considered as the fuel slug for the proliferation resistance core of KALIMER. The radial fuel constituent migration is a general phenomenon in the metallic alloys. This phenomenon may affect the in-reactor performance of metallic fuel rods, influencing such factors as melting temperature, thermal conductivity, power generation rate, phase boundaries and eutectic melting of the fuel slug. Thus, constituent redistribution modeling is essential when developing a metallic fuel performance code. The constituent migration model adopted in this report was based on the Ishida's model and Hofman's theory. A subroutine program has been made and installed into the MACSIS code to simulate constituent redistribution. The radial profile of Zr redistribution was calculated for the ternary metallic fuel, and compared with the measured data.

  16. ACTIVE DELIVERY CABLE TUNED TO DEVICE DEPLOYMENT STATE: ENHANCED VISIBILITY OF NITINOL OCCLUDERS DURING PRE-CLINICAL INTERVENTIONAL MRI

    Science.gov (United States)

    Bell, Jamie A.; Saikus, Christina E.; Ratnayaka, Kanishka; Barbash, Israel M.; Faranesh, Anthony Z.; Franson, Dominique N.; Sonmez, Merdim; Slack, Michael C.; Lederman, Robert J.; Kocaturk, Ozgur

    2012-01-01

    Purpose To develop an active delivery system that enhances visualization of nitinol cardiac occluder devices during deployment under real-time MRI. Materials and Methods We constructed an active delivery cable incorporating a loopless antenna and a custom titanium microscrew to secure the occluder devices. The delivery cable was tuned and matched to 50Ω at 64 MHz with the occluder device attached. We used real-time balanced SSFP in a wide-bore 1.5T scanner. Device-related images were reconstructed separately and combined with surface-coil images. The delivery cable was tested in vitro in a phantom and in vivo in swine using a variety of nitinol cardiac occluder devices. Results In vitro, the active delivery cable provided little signal when the occluder device was detached and maximal signal with the device attached. In vivo, signal from the active delivery cable enabled clear visualization of occluder device during positioning and deployment. Device release resulted in decreased signal from the active cable. Post-mortem examination confirmed proper device placement. Conclusions The active delivery cable enhanced the MRI depiction of nitinol cardiac occluder devices during positioning and deployment, both in conventional and novel applications. We expect enhanced visibility to contribute to effectiveness and safety of new and emerging MRI-guided treatments. PMID:22707441

  17. Self-expandable polytetrafluoroethylene (PTFE)-covered nitinol stent for the palliative treatment of malignant biliary obstruction

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Oong; Jung, Gyoo Sik; Han, Byung Hoon; Shin, Dong Hoon [Gospel Hospital, College of Medicine, Kosin University, Busan (Korea, Republic of); Ko, Ji Ho [Masan Samsung Medical Center, Sungkyunkwan University School of Medicine, Masan (Korea, Republic of)

    2008-06-15

    We wanted to determine the technical and clinical efficacy of placing a self-expandable PTFE-covered nitinol stent for the management of inoperable malignant biliary obstruction. Thirty six patients with inoperable malignant biliary obstructions were treated by placement of self-expandable PTFE-covered nitinol stents (S and G Biotech Corporation, Seongnam, Korea). Clinical evaluation was done with assessment of the serum bilirubin and alkaline phosphatase levels, which were measured before and after stent placement within 1 week, at 1 month and at 3 months. The patient survival rate and stent patency rate were calculated with performing Kaplan-Meier survival analysis. Successful stent placement was achieved in all the patients without procedure-related complication. Pancreatitis as an early complication occurred in two cases. The serum bilirubin and alkaline phosphatase levels were significantly decreased after the procedure. During the follow-up, recurrent obstructive jaundice occurred in six cases; stent migration occurred in four cases and tumor overgrowth occurred in two cases. The survival rates were 97%, 80%, 67% and 59% at 1, 3, 6 and 9 months, respectively. The stent patency rates were 96%, 92%, 86% and 86% at 1, 3, 6 and 9 months, respectively. Self-expandable PTFE-covered nitinol stent placement seems to be technically feasible and effective for the palliative treatment of malignant biliary obstruction.

  18. THE USE OF NITINOL RODS IN SURGICAL TREATMENT OF DEGENERATIVE SCOLIOSIS. 2.5-YEAR FOLLOW-UP

    Directory of Open Access Journals (Sweden)

    Natalia Sergeyevna Morozova

    2016-03-01

    Full Text Available ABSTRACT Objectives: To compare the outcomes of surgical treatment with lumbar fixation using nitinol rods without fusion and with standard lumbar fixation with titanium rods and interbody fusion. Methods: Treatment results of 70 patients with degenerative lumbar scoliosis aged 40 to 82 were analyzed. In all cases pedicle screws and nitinol rods with a diameter of 5.5 mm were used. Thirty patients underwent fixation at L1-S1 and 40 patients underwent fixation at L1-L5. Spinal fusion was not performed. All patients had radiography, CT and MRI performed. The results were assessed according to the Oswestry scale, SRS 22, SF 36 and VAS. The minimum follow-up period for all patients was 2.5 years. For the control group, consisting of 72 patients, pedicle fixation with titanium rods and interbody fusion in the lumbosacral region were performed. Results: The average level of deformity correction equaled 25° (10° - 38°. The analysis of X-ray and CT-scans revealed a single patient with implant instability, two patients with bone resorption around the screws and one patient with rod fractures. Functional radiography 2.5 years after surgery showed an average mobility of the lumbar spine of 21° (15° - 30°. There were no problems at the adjacent levels. Conclusions: The use of nitinol rods in spinal deformity surgery is promising. This technology is an alternative to rigid fixation. Continued gathering of clinical data and its further evaluation is necessary.

  19. Development Program for Natural Aging Aluminum Casting Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Geoffrey K. Sigworth

    2004-05-14

    A number of 7xx aluminum casting alloys are based on the ternary Al-Zn-Mg system. These alloys age naturally to high strength at room temperature. A high temperature solution and aging treatment is not required. Consequently, these alloys have the potential to deliver properties nearly equivalent to conventional A356-T6 (Al-Si-Mg) castings, with a significant cost saving. An energy savings is also possible. In spite of these advantages, the 7xx casting alloys are seldom used, primarily because of their reputation for poor castibility. This paper describes the results obtained in a DOE-funded research study of these alloys, which is part of the DOE-OIT ''Cast Metals Industries of the Future'' Program. Suggestions for possible commercial use are also given.

  20. Functional and structural fatigue of titanium tantalum high temperature shape memory alloys (HT SMAs)

    Energy Technology Data Exchange (ETDEWEB)

    Niendorf, T., E-mail: Thomas.Niendorf@iwt.tu-freiberg.de [Institute of Materials Engineering, Technische Universität Bergakademie Freiberg, 09599 Freiberg (Germany); Krooß, P. [Lehrstuhl für Werkstoffkunde (Materials Science), University of Paderborn, 33098 Paderborn (Germany); Batyrsina, E. [Institut für Werkstoffkunde (Materials Science), Leibniz Universität Hannover, 30823 Garbsen (Germany); Paulsen, A.; Motemani, Y.; Ludwig, A.; Buenconsejo, P.; Frenzel, J.; Eggeler, G. [Institut für Werkstoffe, Ruhr-Universität Bochum, 44801 Bochum (Germany); Maier, H.J. [Institut für Werkstoffkunde (Materials Science), Leibniz Universität Hannover, 30823 Garbsen (Germany)

    2015-01-03

    Due to their high work output and good mechanical properties, actuators made from shape memory alloys (SMAs) are used in numerous applications. Unfortunately, SMAs such as nickel–titanium (Ni–Ti) can only be employed at temperatures up to about 100 °C. Lately, high-temperature shape memory alloys (HT SMAs) have been introduced to overcome this limitation. Ternary systems based on Ni–Ti have been intensively characterized and alloys are available that can operate at elevated temperatures. However, these alloys either contain substantial amounts of expensive noble elements like platinum and palladium, or the materials are brittle. The titanium–tantalum (Ti–Ta) system has been developed to overcome these issues. Binary Ti–Ta provides relatively high M{sub S} temperature combined with excellent workability, but it suffers from fast cyclic degradation. By alloying with third elements this drawback can be overcome: The ternary Ti–Ta–Al alloy shows overall promising properties as will be shown in the present work. In-situ thermo-mechanical cycling experiments were conducted and allowed for evaluation of the factors affecting the functional and structural fatigue of this alloy. Functional fatigue is dominated by ω-phase evolution, while structural fatigue is triggered by an interplay of ω-phase induced embrittlement and deformation constraints imposed by unsuitable texture. In addition, a concept for fatigue life extension proposed very recently for binary Ti–Ta, is demonstrated to be also applicable for the ternary Ti–Ta–Al.

  1. Ternary rare earth-lanthanide sulfides

    Science.gov (United States)

    Takeshita, Takuo; Gschneidner, Jr., Karl A.; Beaudry, Bernard J.

    1987-01-06

    A new ternary rare earth sulfur compound having the formula: La.sub.3-x M.sub.x S.sub.4 where M is a rare earth element selected from the group europium, samarium and ytterbium and x=0.15 to 0.8. The compound has good high-temperature thermoelectric properties and exhibits long-term structural stability up to 1000.degree. C.

  2. Equilibrium study for ternary mixtures of biodiesel

    Science.gov (United States)

    Doungsri, S.; Sookkumnerd, T.; Wongkoblap, A.; Nuchitprasittichai, A.

    2017-11-01

    The liquid-liquid equilibrium (LLE) data for the ternary mixtures of methanol + fatty acid methyl ester (FAME) + palm oil and FAME + palm oil + glycerol at various temperatures from 35 to 55°C, the tie lines and binodial curves were also investigated and plotted in the equilibrium curve. The experimental results showed that the binodial curves of methanol + FAME + palm oil depended significantly with temperature while the binodial curves of FAME + palm oil + glycerol illustrated insignificant change with temperatures. The interaction parameters between liquid pair obtained for NRTL (Nonrandom Two-Liquid) and UNIQUAC (Universal Quasi-Chemical Theory) models from the experimental data were also investigated. It was found that the correlated parameters of UNIQUAC model for system of FAME + palm oil + glycerol, denoted as a13 and a31, were 580.42K and -123.69K, respectively, while those for system of methanol + FAME + palm oil, denoted as a42 and a24, were 71.48 K and 965.57K, respectively. The ternary LLE data reported here would be beneficial for engineers and scientists to use for prediction of yield and purity of biodiesel for the production. The UNIQUAC model agreed well with the experimental data of ternary mixtures of biodiesel.

  3. The Ternary Alpha Energy Distribution Revisited

    Science.gov (United States)

    Wagemans, Cyriel; Janssens, Peter; Heyse, Jan; Serot, Olivier; Geltenbort, Peter; Soldner, Torsten

    2004-02-01

    The shape of the energy distribution of the particles emitted in ternary fission has been studied since the discovery of the phenomenon for a large variety of fissioning systems. The general tendency of the observations is that most particles have a Gaussian-shaped energy distribution, except the α-particles, for which mostly an important non-Gaussian tailing on the low-energy side is reported. The origin of this tailing is generally ascribed to the decay of ternary 5He particles in an α-particle and a neutron. Since the experiments reported in the literature are rarely optimised for measuring the low-energy part of the α-spectrum, we realised good experimental conditions for studying the 235U(nth,f) ternary α energy distribution at the High Flux Reactor of the ILL in Grenoble. Thanks to a very intense and clean neutron beam, a small, very thin sample of highly enriched U could be used, with an activity of only 1.6 Bq. So the measurements could be done without absorber in between the sample and the ΔE-E detector. With the resulting low detection limit of 6 MeV, a clearly asymmetric energy distribution was obtained, in agreement with most data in the literature.

  4. More statistics on intermetallic compounds - ternary phases.

    Science.gov (United States)

    Dshemuchadse, Julia; Steurer, Walter

    2015-05-01

    How many different intermetallic compounds are known so far, and in how many different structure types do they crystallize? What are their chemical compositions, the most abundant ones and the rarest ones? These are some of the questions we are trying to find answers for in our statistical analysis of the structures of the 20,829 intermetallic phases included in the database Pearson's Crystal Data, with the goal of gaining insight into some of their ordering principles. In the present paper, we focus on the subset of 13,026 ternary intermetallics, which crystallize in 1391 different structure types; remarkably, 667 of them have just one representative. What makes these 667 structures so unique that they are not adopted by any other of the known intermetallic compounds? Notably, ternary compounds are known in only 5109 of the 85,320 theoretically possible ternary intermetallic systems so far. In order to get an overview of their chemical compositions we use structure maps with Mendeleev numbers as ordering parameters.

  5. Three-year results of the VIBRANT trial of VIABAHN endoprosthesis versus bare nitinol stent implantation for complex superficial femoral artery occlusive disease.

    Science.gov (United States)

    Geraghty, Patrick J; Mewissen, Mark W; Jaff, Michael R; Ansel, Gary M

    2013-08-01

    The predominant mode of bare nitinol stent failure is diffuse in-stent restenosis, and failure rates correlate to the length and complexity of the treated lesion. Addition of an expanded polytetrafluoroethylene lining to a nitinol stent frame, as found in the VIABAHN endoprosthesis, mitigates the ingrowth of intimal hyperplasia. We compared the long-term outcomes of complex superficial femoral artery disease intervention using the VIABAHN endoprosthesis to those obtained with bare nitinol stent implantation. One hundred forty-eight patients with symptomatic complex superficial femoral artery disease (TransAtlantic Inter-Society Consensus I class C and D lesions, accompanied by intermittent claudication or ischemic rest pain) were randomized to endovascular intervention using either bare nitinol stent implantation (76 patients) or nonheparin-bonded VIABAHN endoprosthesis deployment (72 patients). Patency, limb hemodynamics, and quality of life were evaluated at 1, 6, 12, 24, and 36 months following intervention. The average treated lesion measured 18 ± 8 cm in length, and 58.8% of lesions displayed segmental or complete occlusion. At 3 years, primary patency rates (defined by peak systolic velocity ratio ≤ 2.0 and no target lesion revascularization) did not significantly differ between patients treated with the VIABAHN stent graft and those who received a bare nitinol stent (24.2% vs 25.9%; P = .392). Stent fractures were significantly more common in bare nitinol stents (50.0%) than in the VIABAHN endoprostheses (2.6%). Primary-assisted patency rates were higher in those receiving bare nitinol stents than the VIABAHN stent graft (88.8% vs 69.8%; P = .04), although secondary patency rates did not differ between bare nitinol stent and stent graft recipients (89.3% vs 79.5%; P = .304). There were no instances of procedure-related mortality or amputation. The hemodynamic improvement and quality measures improved equally in both groups. The long-term outcomes of

  6. Primary nitinol stenting in femoropopliteal occlusive disease: a meta-analysis of randomized controlled trials.

    Science.gov (United States)

    Acin, Francisco; de Haro, Joaquin; Bleda, Silvia; Varela, Cesar; Esparza, Leticia

    2012-10-01

    To determine the efficacy and safety of balloon angioplasty (BA) with optional stenting vs. routine stenting with current open cell nitinol stents for femoropopliteal occlusive disease by analyzing the overall results from all available randomized controlled trials. A bibliographic search of electronic medical databases (MEDLINE, Embase, ISI Web of Knowledge, and the Cochrane Central Register of Controlled Trials) was conducted to identify relevant articles from 1960 to July 2011. Of the 701 published articles retrieved, 17 clinical trials randomized patients with symptomatic femoropopliteal occlusive disease to either primary BA or primary stenting. Of these, 4 RCTs involved the use of currently employed high flexibility nitinol stents. Thirteen other trials that employed obsolete, steel, or coated stents were excluded. The technical success rate, the target lesion revascularization (TLR) rate, and the binary restenosis rate at 12 months were primary efficacy endpoints; mortality was the primary safety endpoint. The results are reported as the odds ratio (OR) with 2-tailed 95% confidence intervals (95% CI). The study population was made up of 627 patients (416 men; mean age 67±10 years) and 665 lesions (361 assigned to the primary stenting and 304 to BA). The mean length of the treated lesion was similar in both groups (74.6±45.7 mm in the stenting group vs. 66.7±41.3 mm in the BA group). Technical success was significantly higher in the stenting group compared to BA (95.8% vs. 64.2%; OR 0.31, 95% CI 0.09 to 0.92, p<0.001). Follow-up ranged from 12 to 24 months. Based on 3 studies, the TLR at 12 months favored the stent group (OR 2.47, 95% CI 0.72 to 8.49, p=0.065), but the difference did not reach statistical significance. However, the 12-month binary restenosis rate was significantly lower in the primary stenting group (OR 3.02, 95% CI 1.3 to 6.71, p<0.001). With respect to the safety endpoint, mortality was similar in both groups (OR 0.83, 95% CI 0.39 to 1

  7. Page 1 Structure and superconductivity in ternary systems of ...

    Indian Academy of Sciences (India)

    Structure and superconductivity in ternary systems of compounds 299. Erra B2 structure do not have T. above 1:2 K (Ku and Meisner 1981); (iii) for. Ao.67Pt3B the T. are 1-6, 28 and 56K for A = Ca,Sr and Ba (Shelton 1978) and. (iv) AOs B, A = Th, T = 3 K; A = Y, T = 6K (Ku 1980). 3. Ternary carbides. Of the known ternary ...

  8. Ternary q-Virasoro-Witt Hom-Nambu-Lie algebras

    Energy Technology Data Exchange (ETDEWEB)

    Ammar, F [Faculte des Sciences, Universite de Sfax, BP 1171, 3000 Sfax (Tunisia); Makhlouf, A [Laboratoire de Mathematiques, Informatique et Applications, Universite de Haute Alsace, 4, rue des Freres Lumiere F-68093 Mulhouse (France); Silvestrov, S, E-mail: Faouzi.Ammar@rnn.fss.t, E-mail: Abdenacer.Makhlouf@uha.f, E-mail: sergei.silvestrov@math.lth.s [Centre for Mathematical Sciences, Lund University, Box 118, SE-221 00 Lund (Sweden)

    2010-07-02

    In this paper we construct ternary q-Virasoro-Witt algebras which q-deform the ternary Virasoro-Witt algebras constructed by Curtright, Fairlie and Zachos using su(1, 1) enveloping algebra techniques. The ternary Virasoro-Witt algebras constructed by Curtright, Fairlie and Zachos depend on a parameter and are not Nambu-Lie algebras for all but finitely many values of this parameter. For the parameter values for which the ternary Virasoro-Witt algebras are Nambu-Lie, the corresponding ternary q-Virasoro-Witt algebras constructed in this paper are also Hom-Nambu-Lie because they are obtained from the ternary Nambu-Lie algebras using the composition method. For other parameter values this composition method does not yield a Hom-Nambu-Lie algebra structure for q-Virasoro-Witt algebras. We show however, using a different construction, that the ternary Virasoro-Witt algebras of Curtright, Fairlie and Zachos, as well as the general ternary q-Virasoro-Witt algebras we construct, carry a structure of the ternary Hom-Nambu-Lie algebra for all values of the involved parameters.

  9. Robotic mitral valve annuloplasty with double-arm nitinol U-clips.

    Science.gov (United States)

    Reade, Clifton C; Bower, Curtis E; Bailey, B Marcus; Maziarz, David M; Masroor, Saqib; Kypson, Alan P; Nifong, L Wiley; Chitwood, W Randolph

    2005-04-01

    Robotic mitral valve repair increases precision however operative times are longer. Prior studies have indicated that robotic knot tying is time consuming and it is without potential room for improvement. We therefore investigated tissue approximation devices that may shorten operative times. A 67-year-old female was approached through a right mini-thoracotomy with the da Vinci Robotic Surgical System (Intuitive Surgical, Sunnyvale, CA). Using 12 nitinol U-clips (Coalescent Surgical, Sunnyvale, CA) an annuloplasty band was placed under robotic guidance. Clip placement and deployment times were recorded and statistical comparisons were assessed to prior suture annuloplasties. Clip placement time was 1.3 +/- 0.9 (minutes +/- standard deviation), statistical comparison with first, most recent, and all prior suture annuloplasties proving no significance. Clip deployment time was 0.5 +/- 0.2, whereas knot-tying times and respective statistical comparison for first, most recent, and all prior suture annuloplasties were 2.0 +/- 0.7 (p = 0.003), 1.2 +/- 0.4 (p = 0.0004), and 1.6 +/- 0.6 (p echocardiography performed postoperatively, at 3 months, and at 9 months revealed valvular structural integrity with only minimal mitral regurgitation. U-clips considerably reduce time for annuloplasty over conventional suture and may help reduce operative times as well.

  10. Expression of TGF-β in Fractures Fixed by Nitinol Swan-like Memory Compressive Connectors

    Science.gov (United States)

    Li, M.; Zhang, C. C.; Xu, S. G.; Fu, Q. G.

    2011-07-01

    In this article, the effect of internal fixation of a Nitinol swan-like memory compressive connector (SMC) on the temporal expression of transforming growth factor-β (TGF-β) at fracture sites is evaluated. Specimens were collected from 35 New Zealand rabbits modeled for bilateral humeral fracture fixed with either SMC or stainless dynamic compression plate (DCP). Five rabbits each were killed at day 1, 3, 7, 14, 21, 28, and 56. The local positive staining potency, positive area ratio, and positive index of TGF-β were measured using an immunohistochemistry approach (EnVision) in combination with a computerized image analysis system. TGF-β staining was seen in mesenchymal cells, osteoblasts, chondrocytes, and in the extracellular matrix of fractures fixed in both the SMC and the DCP samples without a significant difference in staining at both the early stages (days 1 and 3) and day 56. A higher TGF-β content was observed in the fractures fixed with SMC when compared to that of DCP from day 7 to 28. As a conclusion, TGF-β is highly expressed in fractures fixed with SMC during chondrogenesis stage and entochondrostosis stage. Finally, the mechanism of how SMC promoting synthesis and secretion of TGF-β in the process of fracture healing has been discussed.

  11. Use of Micropatterned Thin Film Nitinol in Carotid Stents to Augment Embolic Protection

    Directory of Open Access Journals (Sweden)

    Mahdis Shayan

    2016-12-01

    Full Text Available Stenting is an alternative to endarterectomy for the treatment of carotid artery stenosis. However, stenting is associated with a higher risk of procedural stroke secondary to distal thromboembolism. Hybrid stents with a micromesh layer have been proposed to address this complication. We developed a micropatterned thin film nitinol (M-TFN covered stent designed to prevent thromboembolism during carotid intervention. This innovation may obviate the need or work synergistically with embolic protection devices. The proposed double layered stent is low-profile, thromboresistant, and covered with a M-TFN that can be fabricated with fenestrations of varying geometries and sizes. The M-TFN was created in multiple geometries, dimensions, and porosities by sputter deposition. The efficiency of various M-TFN to capture embolic particles was evaluated in different atherosclerotic carotid stenotic conditions through in vitro tests. The covered stent prevented emboli dislodgement in the range of 70%–96% during 30 min duration tests. In vitro vascular cell growth study results showed that endothelial cell elongation, alignment and growth behaviour silhouettes significantly enhance, specifically on the diamond-shape M-TFN, with the dimensions of 145 µm × 20 µm and a porosity of 32%. Future studies will require in vivo testing. Our results demonstrate that M-TFN has a promising potential for carotid artery stenting.

  12. The mid-term efficacy and safety of a permanent nitinol IVC filter (TrapEase)

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wei Chiang [Sungae General Hospital, Seoul (Korea, Republic of); Do, Young Soo; Choo, Sung Wook; Kim, Dong Ik; Kim, Young Wook; Kim, Duk Kyung; Shin, Sung Wook; Park, Kwang Bo; Jeon, Yong Hwan; Choo, In Wook [Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2005-06-15

    1) To evaluate the mid-term efficacy and safety of a permanent nitinol inferior vena cava (IVC) filter; 2) to evaluate filter effectiveness, filter stability and caval occlusion. A prospective evaluation of the TrapEase IVC filter was performed on 42 patients (eight men, 34 women) ranging in age from 22 to 78 years (mean age 66 years). All patients were ill with a high risk of pulmonary embolism (PE). Indications for filter placement were: 1) deep vein thrombosis with recurrent thromboembolism; 2) and/or free-floating thrombus with contraindication to anticoagulation; and 3) complications in achieving adequate anticoagulation. Follow-up evaluations (mean: 15.4 months, range: 2 to 28 months) were performed at 6- and 12-month intervals after the procedure and included clinical histories, chart reviews, plain film, Doppler ultrasounds, and contrasted abdominal CT scans. In follow-up evaluations, the data analysis revealed no cases of symptomatic PE. There were no cases of filter migration, insertion site thrombosis, filter fracture, or vessel wall perforation. During the study, there was one case of filter thrombosis; early symptomatic thrombosis that was successfully treated in the hospital. Of the 42 subjects, eight dead. These deaths were not related to the filter device or the implantation procedure, but to the underlying disease. This study demonstrates that the TrapEase permanent IVC filter is a safe and an effective device with low complication rates and is best used in patients with thromboembolic disease with a high risk of PE.

  13. The underdilation of nitinol stents at TIPS implantation: Solution or illusion?

    Science.gov (United States)

    Mollaiyan, Ashkan; Bettinger, Dominik; Rössle, Martin

    2017-04-01

    This study investigates the behaviour of self-expanding nitinol stents at the time of TIPS-implantation and thereafter. Hundred consecutive patients with cirrhosis receiving a TIPS revision were included. The smallest stent diameter was measured radiologically immediately after implantation and before shunt revision. Accuracy of the measurement was assessed by comparing the nominal stent diameter with the largest stent diameter measured at the time of revision. Pearson correlation between largest measured and nominal diameters was excellent (r=0.952, pballoons were used. During a mean follow-up of 12.7±17.8months (median 3 months, range 1-81) stents expanded by 0.5-1.6mm dependent on the nominal stent size (8, 9, 10mm) and the grade of primary underdilation. No significant difference was found between Viatorr and bare stents. At TIPS-implantation, the compliance of the surrounding tissue predominantly determines the stent diameter. The nominal size of the stent or the dilatation balloon has little influence. Accurate adjustment of a desired pressure gradient is, therefore, not possible. During follow-up, stents expand towards their nominal diameter questioning the usefulness of underdilation. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Thermodynamic database of multi-component Mg alloys and its application to solidification and heat treatment

    Directory of Open Access Journals (Sweden)

    Guanglong Xu

    2016-12-01

    Full Text Available An overview about one thermodynamic database of multi-component Mg alloys is given in this work. This thermodynamic database includes thermodynamic descriptions for 145 binary systems and 48 ternary systems in 23-component (Mg–Ag–Al–Ca–Ce–Cu–Fe–Gd–K–La–Li–Mn–Na–Nd–Ni–Pr–Si–Sn–Sr–Th–Y–Zn–Zr system. First, the major computational and experimental tools to establish the thermodynamic database of Mg alloys are briefly described. Subsequently, among the investigated binary and ternary systems, representative binary and ternary systems are shown to demonstrate the major feature of the database. Finally, application of the thermodynamic database to solidification simulation and selection of heat treatment schedule is described.

  15. Lubricated sliding wear behaviour of Ni-P-W multilayered alloy coatings produced by pulse plating

    DEFF Research Database (Denmark)

    Panagopoulos, C. N.; Papachristos, V. D.; Christoffersen, Lasse

    2000-01-01

    The lubricated sliding wear behaviour of Ni-P-W multilayered alloy coatings sliding against hardened steel discs was studied, in a pin-on-disc set-up. The multilayered coatings had been deposited on mild steel pins by pulse plating and they consisted of ternary Ni-P-W layers of high and low W...

  16. Low alloy additions of iron, silicon, and aluminum to uranium: a literature survey

    Energy Technology Data Exchange (ETDEWEB)

    Ludwig, R.L.

    1980-12-31

    A survey of the literature has been made on the experimental results of small additions of iron, silicon, and aluminum to uranium. Information is also included on the constitution, mechanical properties, heat treatment, and deformation of various binary and ternary alloys. 42 references, 24 figures, 13 tables.

  17. Neutron Damage and MAX Phase Ternary Compounds

    Energy Technology Data Exchange (ETDEWEB)

    Barsoum, Michael [Drexel Univ., Philadelphia, PA (United States); Hoffman, Elizabeth [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Sindelar, Robert [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Garcua-Duaz, Brenda [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Kohse, Gordon [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2014-06-17

    The Demands of Gen IV nuclear power plants for long service life under neutron radiation at high temperature are severe. Advanced materials that would withstand high temperatures (up to 1000+ C) to high doses in a neutron field would be ideal for reactor internal structures and would add to the long service life and reliability of the reactors. The objective of this work is to investigate the response of a new class of machinable, conductive, layered, ternary transition metal carbides and nitrides - the so-called MAX phases - to low and moderate neutron dose levels.

  18. Design of a Shape Memory Alloy deployment hinge for reflector facets

    Science.gov (United States)

    Anders, W. S.; Rogers, C. A.

    1991-01-01

    A design concept for a Shape Memory Alloy (SMA) actuated hinge mechanism for deploying segmented facet-type reflector surfaces on antenna truss structures is presented. The mechanism uses nitinol, a nickel-titanium shape memory alloy, as a displacement-force micro-actuator. An electrical current is used to resistively heat a 'plastically' elongated SMA actuator wire, causing it to contract in response to a thermally-induced phase transformation. The resulting tension creates a moment, imparting rotary motion between two adjacent panels. Mechanical stops are designed into the device to limit its range of motion and to establish positioning accuracy at the termination of deployment. The concept and its operation are discussed in detail, and an analytical dynamic simulation model is presented. The model has been used to perform nondimensionalized parametric design studies.

  19. Solidification processing of intermetallic Nb-Al alloys

    Science.gov (United States)

    Smith, Preston P.; Oliver, Ben F.; Noebe, Ronald D.

    1992-01-01

    Several Nb-Al alloys, including single-phase NbAl3 and the eutectic of Nb2Al and NbAl3, were prepared either by nonconsumable arc melting in Ar or by zone processing in He following initial induction melting and rod casting, and the effect of the solidification route on the microstructure and room-temperature mechanical properties of these alloys was investigated. Automated control procedures and melt conditions for directional solidification of NbAl3 and the Nb2Al/Nb3Al eutectic were developed; high purity and stoichiometry were obtained. The effects of ternary additions of Ti and Ni are described.

  20. Lead activity in Pb-Sb-Bi alloys

    Directory of Open Access Journals (Sweden)

    A. S. Kholkina

    2014-11-01

    Full Text Available The present work is devoted to the study of lead thermodynamic activity in the Pb-Sb-Bi alloys. The method for EMF measurements of the concentration cell: (–Pb|KCl-PbCl2¦¦KCl-PbCl2|Pb-(Sb-Bi(+ was used. The obtained concentration dependences of the galvanic cell EMF are described by linear equations. The lead activity in the ternary liquid-metal alloy demonstrates insignificant negative deviations from the behavior of ideal solutions.

  1. Whole shaft visibility and mechanical performance for active MR catheters using copper-nitinol braided polymer tubes

    Directory of Open Access Journals (Sweden)

    McVeigh Elliot R

    2009-08-01

    Full Text Available Abstract Background Catheter visualization and tracking remains a challenge in interventional MR. Active guidewires can be made conspicuous in "profile" along their whole shaft exploiting metallic core wire and hypotube components that are intrinsic to their mechanical performance. Polymer-based catheters, on the other hand, offer no conductive medium to carry radio frequency waves. We developed a new "active" catheter design for interventional MR with mechanical performance resembling braided X-ray devices. Our 75 cm long hybrid catheter shaft incorporates a wire lattice in a polymer matrix, and contains three distal loop coils in a flexible and torquable 7Fr device. We explored the impact of braid material designs on radiofrequency and mechanical performance. Results The incorporation of copper wire into in a superelastic nitinol braided loopless antenna allowed good visualization of the whole shaft (70 cm in vitro and in vivo in swine during real-time MR with 1.5 T scanner. Additional distal tip coils enhanced tip visibility. Increasing the copper:nitinol ratio in braiding configurations improved flexibility at the expense of torquability. We found a 16-wire braid of 1:1 copper:nitinol to have the optimum balance of mechanical (trackability, flexibility, torquability and antenna (signal attenuation properties. With this configuration, the temperature increase remained less than 2°C during real-time MR within 10 cm horizontal from the isocenter. The design was conspicuous in vitro and in vivo. Conclusion We have engineered a new loopless antenna configuration that imparts interventional MR catheters with satisfactory mechanical and imaging characteristics. This compact loopless antenna design can be generalized to visualize the whole shaft of any general-purpose polymer catheter to perform safe interventional procedures.

  2. Endovascular repair of arterial iliac vessel wall lesions with a self-expandable nitinol stent graft system.

    Directory of Open Access Journals (Sweden)

    Birger Mensel

    Full Text Available To assess the therapeutic outcome after endovascular repair of iliac arterial lesions (IALs using a self-expandable Nitinol stent graft system.Between July 2006 and March 2013, 16 patients (13 males, mean age: 68 years with a self-expandable Nitinol stent graft. A total of 19 lesions were treated: nine true aneurysms, two anastomotic aneurysms, two dissections, one arteriovenous fistula, two type 1B endoleaks after endovascular aneurysm repair, one pseudoaneurysm, and two perforations after angioplasty. Pre-, intra-, and postinterventional imaging studies and the medical records were analyzed for technical and clinical success and postinterventional complications.The primary technical and clinical success rate was 81.3% (13/16 patients and 75.0% (12/16, respectively. Two patients had technical failure due to persistent type 1A endoleak and another patient due to acute stent graft thrombosis. One patient showed severe stent graft kinking on the first postinterventional day. In two patients, a second intervention was performed. The secondary technical and clinical success rate was 87.5% (14/16 and 93.8% (15/16. The minor complication rate was 6.3% (patient with painful hematoma at the access site. The major complication rate was 6.3% (patient with ipsilateral deep vein thrombosis. During median follow-up of 22.4 months, an infection of the aneurysm sac in one patient and a stent graft thrombosis in another patient were observed.Endovascular repair of various IALs with a self-expandable Nitinol stent graft is safe and effective.

  3. Balanced ternary addition using a gated silicon nanowire

    NARCIS (Netherlands)

    Mol, J.A.; Van der Heijden, J.; Verduijn, J.; Klein, M.; Remacle, F.; Rogge, S.

    2011-01-01

    Ternary logic has the lowest cost of complexity, here, we demonstrate a CMOS hardware implementation of a ternary adder using a silicon metal-on-insulator single electron transistor. Gate dependent rectifying behavior of a single electron transistor (SET) results in a robust three-valued output as a

  4. Density-Driven segregation in Binary and Ternary Granular Systems

    NARCIS (Netherlands)

    Windows-Yule, Kit; Parker, David

    2015-01-01

    We present a first experimental study of density-induced segregation within a three-dimensional, vibrofluidised, ternary granular system. Using Positron Emission Particle Tracking (PEPT), we study the steady-state particle distributions achieved by binary and ternary granular beds under a variety of

  5. A high-speed interconnect network using ternary logic

    DEFF Research Database (Denmark)

    Madsen, Jens Kargaard; Long, S. I.

    1995-01-01

    This paper describes the design and implementation of a high-speed interconnect network (ICN) for a multiprocessor system using ternary logic. By using ternary logic and a fast point-to-point communication technique called STARI (Self-Timed At Receiver's Input), the communication between...

  6. Densities and Excess Molar Volume for the Ternary Systems (1 ...

    African Journals Online (AJOL)

    methylimidazolium methyl sulphate ([BMIM]+[MeSO4]-) were determined. The ternary systems studied were ([BMIM]+[MeSO4]-+ nitromethane + methanol or ethanol or 1-propanol) at the temperatures (303.15 and 313.15) K. The ternary excess molar ...

  7. Single polymer-based ternary electronic memory material and device.

    Science.gov (United States)

    Liu, Shu-Juan; Wang, Peng; Zhao, Qiang; Yang, Hui-Ying; Wong, Jenlt; Sun, Hui-Bin; Dong, Xiao-Chen; Lin, Wen-Peng; Huang, Wei

    2012-06-05

    A ternary polymer memory device based on a single polymer with on-chain Ir(III) complexes is fabricated by combining multiple memory mechanisms into one system. Excellent ternary memory performances-low reading, writing, and erasing voltages and good stability for all three states-are achieved. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. In-Vitro Corrosion Studies of Bioabsorbable Alloys

    Science.gov (United States)

    Gill, P.; Munroe, N.

    Magnesium alloys have inspired a significant amount of attention from researchers all over the world for cardiovascular and orthopedic applications due to their light weight, mechanical integrity and degradation behavior. In this investigation, cast manufactured binary, ternary and quaternary magnesium alloys were studied for their degradation behavior by potentiodynamic polarization tests in phosphate buffer saline solution (PBS) and PBS containing amino acids (cysteine, C and tryptophan, W) at 37 °C. Electrochemical impedance spectroscopy (EIS) tests were performed to determine the charge transfer resistance and immersion tests were performed to assess corrosion rate and hydrogen evolution from the alloys. Furthermore, the surface morphology and surface chemistry of the alloys were observed by scanning electron microscopy (SEM) and X-ray diffraction (XRD).

  9. Polycation-Based Ternary Gene Delivery System.

    Science.gov (United States)

    Liu, Shuai; Guo, Tianying

    2015-01-01

    Recent progress in gene therapy has opened the door for various human diseases. The greatest challenge that gene vectors still face is the ability to sufficiently deliver nucleic acid into target cells. To overcome various barriers, plenty of researches have been undertaken utilizing diverse strategies, among which a wide variety of polycation/pDNA vectors have been developed and explored frequently. For enhanced transfection efficiency, polycations are constantly utilized with covalent modifications, which however lead to reduced positive charge density and changed properties of polycation/pDNA complexes. Accordingly, non-covalent or ternary strategy is proposed. The cationic properties of polycations can be retained and the transfection efficiency can be enhanced by introducing additional polymers with functional groups via non-covalent assembly. This review will discuss the construction and advantages of ternary complexes gene delivery system, including low toxicity and enhanced gene expression both in vitro and in vivo. Recent progress and expectations with promising results that may have some reference for clinical application are also discussed.

  10. Plasmonic spectral tunability of conductive ternary nitrides

    Energy Technology Data Exchange (ETDEWEB)

    Kassavetis, S.; Patsalas, P., E-mail: ppats@physics.auth.gr [Department of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki (Greece); Bellas, D. V.; Lidorikis, E. [Department of Materials Science and Engineering, University of Ioannina, GR-45110 Ioannina (Greece); Abadias, G. [Institut Pprime, Département Physique et Mécanique des Matériaux, Université de Poitiers-CNRS-ENSMA, 86962 Chasseneuil-Futuroscope (France)

    2016-06-27

    Conductive binary transition metal nitrides, such as TiN and ZrN, have emerged as a category of promising alternative plasmonic materials. In this work, we show that ternary transition metal nitrides such as Ti{sub x}Ta{sub 1−x}N, Ti{sub x}Zr{sub 1−x}N, Ti{sub x}Al{sub 1−x}N, and Zr{sub x}Ta{sub 1−x}N share the important plasmonic features with their binary counterparts, while having the additional asset of the exceptional spectral tunability in the entire visible (400–700 nm) and UVA (315–400 nm) spectral ranges depending on their net valence electrons. In particular, we demonstrate that such ternary nitrides can exhibit maximum field enhancement factors comparable with gold in the aforementioned broadband range. We also critically evaluate the structural features that affect the quality factor of the plasmon resonance and we provide rules of thumb for the selection and growth of materials for nitride plasmonics.

  11. Irregular Homogeneity Domains in Ternary Intermetallic Systems

    Directory of Open Access Journals (Sweden)

    Jean-Marc Joubert

    2015-12-01

    Full Text Available Ternary intermetallic A–B–C systems sometimes have unexpected behaviors. The present paper examines situations in which there is a tendency to simultaneously form the compounds ABx, ACx and BCx with the same crystal structure. This causes irregular shapes of the phase homogeneity domains and, from a structural point of view, a complete reversal of site occupancies for the B atom when crossing the homogeneity domain. This work reviews previous studies done in the systems Fe–Nb–Zr, Hf–Mo–Re, Hf–Re–W, Mo–Re–Zr, Re–W–Zr, Cr–Mn–Si, Cr–Mo–Re, and Mo–Ni–Re, and involving the topologically close-packed Laves, χ and σ phases. These systems have been studied using ternary isothermal section determination, DFT calculations, site occupancy measurement using joint X-ray, and neutron diffraction Rietveld refinement. Conclusions are drawn concerning this phenomenon. The paper also reports new experimental or calculated data on Co–Cr–Re and Fe–Nb–Zr systems.

  12. Vertebral Augmentation with Nitinol Endoprosthesis: Clinical Experience in 40 Patients with 1-Year Follow-up

    Energy Technology Data Exchange (ETDEWEB)

    Anselmetti, Giovanni Carlo, E-mail: gc.anselmetti@fastwebnet.it [Villa Maria Hospital, Interventional Radiology Unit (Italy); Manca, Antonio, E-mail: anto.manca@gmail.com [Institute for Cancer Research and Treatment (IRCC), Interventional Radiology Unit (Italy); Marcia, Stefano, E-mail: stemarcia@gmail.com [Institute of Radiology, University of Cagliari (Italy); Chiara, Gabriele, E-mail: gabriele.chiara@ircc.it [Institute for Cancer Research and Treatment (IRCC), Interventional Radiology Unit (Italy); Marini, Stefano, E-mail: stemarini@gmail.com [Institute of Radiology, University of Cagliari (Italy); Baroud, Gamal, E-mail: gamalbaroud@gmail.com [University of Sherbrooke, Departement de Genie Mecanique (Canada); Regge, Daniele, E-mail: daniele.regge@ircc.it [Institute for Cancer Research and Treatment (IRCC), Radiology Unit (Italy); Montemurro, Filippo, E-mail: filippo.montemurro@ircc.it [Institute for Cancer Research and Treatment (IRCC), Internal Medicine Unit (Italy)

    2013-05-08

    PurposeThis study was designed to assess the clinical outcomes of patients treated by vertebral augmentation with nitinol endoprosthesis (VNE) to treat painful vertebral compression fractures.MethodsForty patients with one or more painful osteoporotic VCF, confirmed by MRI and accompanied by back-pain unresponsive to a minimum 2 months of conservative medical treatment, underwent VNE at 42 levels. Preoperative and postoperative pain measured with Visual Analog Scale (VAS), disability measured by Oswestry Disability Index (ODI), and vertebral height restoration (measured with 2-dimensional reconstruction CT) were compared at last follow-up (average follow-up 15 months). Cement extravasation, subsequent fractures, and implant migration were recorded.ResultsLong-term follow-up was obtained in 38 of 40 patients. Both VAS and ODI significantly improved from a median of 8.0 (range 5–10) and 66 % (range 44–88 %) to 0.5 (range 0–8) and 6 % (range 6–66 %), respectively, at 1 year (p < 0.0001). Vertebral height measurements comparing time points increased in a statistically significant manner (ANOVA, p < 0.001). Overall cement extravasation rate was 9.5 %. Discal and venous leakage rates were 7.1 and 0 % respectively. No symptomatic extravasations occurred. Five of 38 (13.1 %) patients experienced new spontaneous, osteoporotic fractures. No device change or migration was observed.ConclusionsVNE is a safe and effective procedure that is able to provide long-lasting pain relief and durable vertebral height gain with a low rate of new fractures and cement leakages.

  13. An in vivo pilot study of a microporous thin film nitinol-covered stent to assess the effect of porosity and pore geometry on device interaction with the vessel wall.

    Science.gov (United States)

    Chun, Youngjae; Kealey, Colin P; Levi, Daniel S; Rigberg, David A; Chen, Yanfei; Tillman, Bryan W; Mohanchandra, K P; Shayan, Mahdis; Carman, Gregory P

    2017-03-01

    Sputter-deposited thin film nitinol constructs with various micropatterns were fabricated to evaluate their effect on the vessel wall in vivo when used as a covering for commercially available stents. Thin film nitinol constructs were used to cover stents and deployed in non-diseased swine arteries. Swine were sacrificed after approximately four weeks and the thin film nitinol-covered stents were removed for histopathologic evaluation. Histopathology revealed differences in neointimal thickness that correlated with the thin film nitinol micropattern. Devices covered with thin film nitinol with a lateral × vertical length = 20 × 40 µm diamond pattern had minimal neointimal growth with well-organized cell architecture and little evidence of ongoing inflammation. Devices covered with thin film nitinol with smaller fenestrations exhibited a relatively thick neointimal layer with inflammation and larger fenestrations showed migration of inflammatory and smooth muscle cells through the micro fenestrations. This "proof-of-concept" study suggests that there may be an ideal thin film nitinol porosity and pore geometry to encourage endothelialization and incorporation of the device into the vessel wall. Future work will be needed to determine the optimal pore size and geometry to minimize neointimal proliferation and in-stent stenosis.

  14. BRAZING ALLOYS

    Science.gov (United States)

    Donnelly, R.G.; Gilliland, R.G.; Slaughter, G.M.

    1962-02-20

    A brazing alloy is described which, in the molten state, is characterized by excellent wettability and flowability and is capable of forming a corrosion-resistant brazed joint. At least one component of said joint is graphite and the other component is a corrosion-resistant refractory metal. The brazing alloy consists essentially of 40 to 90 wt % of gold, 5 to 35 wt% of nickel, and 1 to 45 wt% of tantalum. (AEC)

  15. Design and development of novel antibacterial Ti-Ni-Cu shape memory alloys for biomedical application.

    Science.gov (United States)

    Li, H F; Qiu, K J; Zhou, F Y; Li, L; Zheng, Y F

    2016-11-29

    In the case of medical implants, foreign materials are preferential sites for bacterial adhesion and microbial contamination, which can lead to the development of prosthetic infections. Commercially biomedical TiNi shape memory alloys are the most commonly used materials for permanent implants in contact with bone and dental, and the prevention of infections of TiNi biomedical shape memory alloys in clinical cases is therefore a crucial challenge for orthopaedic and dental surgeons. In the present study, copper has been chosen as the alloying element for design and development novel ternary biomedical Ti‒Ni‒Cu shape memory alloys with antibacterial properties. The effects of copper alloying element on the microstructure, mechanical properties, corrosion behaviors, cytocompatibility and antibacterial properties of biomedical Ti‒Ni‒Cu shape memory alloys have been systematically investigated. The results demonstrated that Ti‒Ni‒Cu alloys have good mechanical properties, and remain the excellent shape memory effects after adding copper alloying element. The corrosion behaviors of Ti‒Ni‒Cu alloys are better than the commercial biomedical Ti‒50.8Ni alloys. The Ti‒Ni‒Cu alloys exhibit excellent antibacterial properties while maintaining the good cytocompatibility, which would further guarantee the potential application of Ti‒Ni‒Cu alloys as future biomedical implants and devices without inducing bacterial infections.

  16. Evaluation of Nb-base alloys for the divertor structure in fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Purdy, I.M. [Argonne National Laboratory, Upton, IL (United States)

    1996-04-01

    Niobium-base alloys are candidate materials for the divertor structure in fusion reactors. For this application, an alloy should resist aqueous corrosion, hydrogen embrittlement, and radiation damage and should have high thermal conductivity and low thermal expansion. Results of corrosion and embrittlement screening tests of several binary and ternary Nb alloys in high-temperature water indicated the Mb-1Zr, Nb-5MO-1Zr, and Nb-5V-1Z4 (wt %) showed sufficient promise for further investigation. These alloys, together with pure Nb and Zircaloy-4 have been exposed to high purity water containing a low concentration of dissolved oxygen (<12 ppb) at 170, 230, and 300{degrees}C for up to {approx}3200 h. Weight-change data, microstructural observations, and qualitative mechanical-property evaluation reveal that Nb-5V-1Zr is the most promising alloy at higher temperatures. Below {approx}200{degrees}C, the alloys exhibit similiar corrosion behavior.

  17. Ultrathin ternary semiconductor TlGaSe2 phototransistors with broad-spectral response

    Science.gov (United States)

    Yang, Shengxue; Wu, Minghui; Wang, Hui; Cai, Hui; Huang, Li; Jiang, Chengbao; Tongay, Sefaattin

    2017-09-01

    Ternary layered III-III-VI2-type metal chalcogenides are a comparatively new group of semiconductors and have attracted strong interest due to their distinct optical and electrical properties in view of potential applications in nonlinear optical, acousto-optical and optoelectronic devices. Here, we report on the fabrication of two-terminal phototransistors based on ultrathin direct-bandgap TlGaSe2 sheets for the first time. Devices exhibit typical p-type conducting behaviors with current on/off ratio of ~102 and gate-tunable transport characteristics. The photocurrent presents stable and reproducible response for various wavelengths of light from ultraviolet (UV) to near-infrared region, confirming the broadband photodetection capability. Photoresponsive behavior of ultrathin TlGaSe2 phototransistors can be modulated by the incident optical power density or wavelength, as well as bias or back-gate voltages. Owing to the presence of direct bandgap, devices possess high photoresponsivity (270 mA W-1) under white light in vacuum, and it is higher than that of single-layer MoS2 phototransistor and graphene photodetectors, accompanying by a fast response time of ~0.2 s. Our studies introduce ternary alloy monochalcogenides phototransistors, and expand the library of ultrathin flexible semiconductors.

  18. Direct observation of interface and nanoscale compositional modulation in ternary III-As heterostructure nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Venkatesan, Sriram; Scheu, Christina [Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, Butenandstr 5-13(E), 81377 München (Germany); Madsen, Morten H.; Krogstrup, Peter; Johnson, Erik [Nano-Science Center and Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark); Schmid, Herbert [INM-Leibniz Institute for New Materials, 66123 Saarbrücken (Germany)

    2013-08-05

    Straight, axial InAs nanowire with multiple segments of Ga{sub x}In{sub 1−x}As was grown. High resolution X-ray energy-dispersive spectroscopy (EDS) mapping reveals the distribution of group III atoms at the axial interfaces and at the sidewalls. Significant Ga enrichment, accompanied by a structural change is observed at the Ga{sub x}In{sub 1−x}As/InAs interfaces and a higher Ga concentration for the early grown Ga{sub x}In{sub 1−x}As segments. The elemental map and EDS line profile infer Ga enrichment at the facet junctions between the sidewalls. The relative chemical potentials of ternary alloys and the thermodynamic driving force for liquid to solid transition explains the growth mechanisms behind the enrichment.

  19. Quantitative Comparison of Ternary Eutectic Phase-Field Simulations with Analytical 3D Jackson-Hunt Approaches

    Science.gov (United States)

    Steinmetz, Philipp; Kellner, Michael; Hötzer, Johannes; Nestler, Britta

    2018-02-01

    For the analytical description of the relationship between undercoolings, lamellar spacings and growth velocities during the directional solidification of ternary eutectics in 2D and 3D, different extensions based on the theory of Jackson and Hunt are reported in the literature. Besides analytical approaches, the phase-field method has been established to study the spatially complex microstructure evolution during the solidification of eutectic alloys. The understanding of the fundamental mechanisms controlling the morphology development in multiphase, multicomponent systems is of high interest. For this purpose, a comparison is made between the analytical extensions and three-dimensional phase-field simulations of directional solidification in an ideal ternary eutectic system. Based on the observed accordance in two-dimensional validation cases, the experimentally reported, inherently three-dimensional chain-like pattern is investigated in extensive simulation studies. The results are quantitatively compared with the analytical results reported in the literature, and with a newly derived approach which uses equal undercoolings. A good accordance of the undercooling-spacing characteristics between simulations and the analytical Jackson-Hunt apporaches are found. The results show that the applied phase-field model, which is based on the Grand potential approach, is able to describe the analytically predicted relationship between the undercooling and the lamellar arrangements during the directional solidification of a ternary eutectic system in 3D.

  20. Kinetic Phase Diagrams of Ternary Al-Cu-Li System during Rapid Solidification: A Phase-Field Study.

    Science.gov (United States)

    Yang, Xiong; Zhang, Lijun; Sobolev, Sergey; Du, Yong

    2018-02-08

    Kinetic phase diagrams in technical alloys at different solidification velocities during rapid solidification are of great importance for guiding the novel alloy preparation, but are usually absent due to extreme difficulty in performing experimental measurements. In this paper, a phase-field model with finite interface dissipation was employed to construct kinetic phase diagrams in the ternary Al-Cu-Li system for the first time. The time-elimination relaxation scheme was utilized. The solute trapping phenomenon during rapid solidification could be nicely described by the phase-field simulation, and the results obtained from the experiment measurement and/or the theoretical model were also well reproduced. Based on the predicted kinetic phase diagrams, it was found that with the increase of interface moving velocity and/or temperature, the gap between the liquidus and solidus gradually reduces, which illustrates the effect of solute trapping and tendency of diffusionless solidification.

  1. The New Nitinol Conformable Self-Expandable Metal Stents for Malignant Colonic Obstruction: A Pilot Experience as Bridge to Surgery Treatment

    Directory of Open Access Journals (Sweden)

    Roberto Di Mitri

    2014-01-01

    Full Text Available Introduction. Self-expandable metal stents (SEMS are a nonsurgical option for treatment of malignant colorectal obstruction also as a bridge to surgery approach. The new nitinol conformable stent has improved clinical outcomes in these kinds of patients. We report a pilot experience with nitinol conformable SEMS placement as bridge to surgery treatment in patients with colorectal obstruction. Materials and Methods. Between April and August 2012, we collected data on colonic nitinol conformable SEMS placement in a cohort of consecutive symptomatic patients, with malignant colorectal obstruction, who were treated as a bridge to surgery. Technical success, clinical success, and adverse events were recorded. Results. Ten patients (7 male (70%, with a mean age of 69.2 ± 10.1, were evaluated. The mean length of the stenosis was 3.6 ± 0.6 cm. Five patients (50% were treated on an emergency basis. The median time from stent placement to surgery was 16 days (interquartile range 7–21. Technical and clinical success was achieved in all patients with a significant early improvement of symptoms. No adverse events due to the SEMS placement were observed. Conclusion. This pilot study confirmed the important role of nitinol conformable SEMS as a bridge to surgery option in the treatment of symptomatic malignant colorectal obstruction.

  2. Fabrication of biodegradable Zn-Al-Mg alloy: Mechanical properties, corrosion behavior, cytotoxicity and antibacterial activities.

    Science.gov (United States)

    Bakhsheshi-Rad, H R; Hamzah, E; Low, H T; Kasiri-Asgarani, M; Farahany, S; Akbari, E; Cho, M H

    2017-04-01

    In this work, binary Zn-0.5Al and ternary Zn-0.5Al-xMg alloys with various Mg contents were investigated as biodegradable materials for implant applications. Compared with Zn-0.5Al (single phase), Zn-0.5Al-xMg alloys consisted of the α-Zn and Mg 2 (Zn, Al) 11 with a fine lamellar structure. The results also revealed that ternary Zn-Al-Mg alloys presented higher micro-hardness value, tensile strength and corrosion resistance compared to the binary Zn-Al alloy. In addition, the tensile strength and corrosion resistance increased with increasing the Mg content in ternary alloys. The immersion tests also indicated that the corrosion rates in the following order Zn-0.5Al-0.5Mgcorrosion rate, good biocompatibility and antibacterial activities was believed to be a good candidate as a biodegradable implant material. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Compositional trends in Ni-Mn-Ga Heusler alloys: first-principles approach

    Directory of Open Access Journals (Sweden)

    Sokolovskiy Vladimir

    2015-01-01

    Full Text Available In this work we present a systematic investigation of magnetic and structural properties of a broad range of Ni-Mn-Ga alloys by means of the density functional theory. Calculations are carried out for the cubic austenitic phase. The effect of chemical disorder is simulated by using the single-site coherent-potential approximation and the spin-polarized generalized gradient approximation. Equilibrium lattice parameters, bulk moduli, total magnetic moments, and formation energies of a wide range of Heusler alloys have been mapped on compositional ternary diagrams that give a bigger picture of the variety of physical properties of this family of alloys.

  4. Facile Synthesis of Ternary Boron Carbonitride Nanotubes

    Directory of Open Access Journals (Sweden)

    Luo Lijie

    2009-01-01

    Full Text Available Abstract In this study, a novel and facile approach for the synthesis of ternary boron carbonitride (B–C–N nanotubes was reported. Growth occurred by heating simple starting materials of boron powder, zinc oxide powder, and ethanol absolute at 1150 °C under a mixture gas flow of nitrogen and hydrogen. As substrate, commercial stainless steel foil with a typical thickness of 0.05 mm played an additional role of catalyst during the growth of nanotubes. The nanotubes were characterized by SEM, TEM, EDX, and EELS. The results indicate that the synthesized B–C–N nanotubes exhibit a bamboo-like morphology and B, C, and N elements are homogeneously distributed in the nanotubes. A catalyzed vapor–liquid–solid (VLS mechanism was proposed for the growth of the nanotubes.

  5. First principles theoretical investigations of low Young's modulus beta Ti-Nb and Ti-Nb-Zr alloys compositions for biomedical applications.

    Science.gov (United States)

    Karre, Rajamallu; Niranjan, Manish K; Dey, Suhash R

    2015-05-01

    High alloyed β-phase stabilized titanium alloys are known to provide comparable Young's modulus as that to the human bones (~30 GPa) but is marred by its high density. In the present study the low titanium alloyed compositions of binary Ti-Nb and ternary Ti-Nb-Zr alloy systems, having stable β-phase with low Young's modulus are identified using first principles density functional framework. The theoretical results suggest that the addition of Nb in Ti and Zr in Ti-Nb increases the stability of the β-phase. The β-phase in binary Ti-Nb alloys is found to be fully stabilized from 22 at.% of Nb onwards. The calculated Young's moduli of binary β-Ti-Nb alloy system are found to be lower than that of pure titanium (116 GPa). For Ti-25(at.%)Nb composition the calculated Young's modulus comes out to be ~80 GPa. In ternary Ti-Nb-Zr alloy system, the Young's modulus of Ti-25(at.%)Nb-6.25(at.%)Zr composition is calculated to be ~50 GPa. Furthermore, the directional Young's moduli of these two selected binary (Ti-25(at.%)Nb) and ternary alloy (Ti-25(at.%)Nb-6.25(at.%)Zr) compositions are found to be nearly isotropic in all crystallographic directions. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. 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...

  7. Theoretical Studies of Hydrogen Storage Alloys.

    Energy Technology Data Exchange (ETDEWEB)

    Jonsson, Hannes

    2012-03-22

    Theoretical calculations were carried out to search for lightweight alloys that can be used to reversibly store hydrogen in mobile applications, such as automobiles. Our primary focus was on magnesium based alloys. While MgH{sub 2} is in many respects a promising hydrogen storage material, there are two serious problems which need to be solved in order to make it useful: (i) the binding energy of the hydrogen atoms in the hydride is too large, causing the release temperature to be too high, and (ii) the diffusion of hydrogen through the hydride is so slow that loading of hydrogen into the metal takes much too long. In the first year of the project, we found that the addition of ca. 15% of aluminum decreases the binding energy to the hydrogen to the target value of 0.25 eV which corresponds to release of 1 bar hydrogen gas at 100 degrees C. Also, the addition of ca. 15% of transition metal atoms, such as Ti or V, reduces the formation energy of interstitial H-atoms making the diffusion of H-atoms through the hydride more than ten orders of magnitude faster at room temperature. In the second year of the project, several calculations of alloys of magnesium with various other transition metals were carried out and systematic trends in stability, hydrogen binding energy and diffusivity established. Some calculations of ternary alloys and their hydrides were also carried out, for example of Mg{sub 6}AlTiH{sub 16}. It was found that the binding energy reduction due to the addition of aluminum and increased diffusivity due to the addition of a transition metal are both effective at the same time. This material would in principle work well for hydrogen storage but it is, unfortunately, unstable with respect to phase separation. A search was made for a ternary alloy of this type where both the alloy and the corresponding hydride are stable. Promising results were obtained by including Zn in the alloy.

  8. Effect of wire fretting on the corrosion resistance of common medical alloys.

    Science.gov (United States)

    Siddiqui, Danyal A; Sivan, Shiril; Weaver, Jason D; Di Prima, Matthew

    2017-11-01

    Metallic medical devices such as intravascular stents can undergo fretting damage in vivo that might increase their susceptibility to pitting corrosion. As a result, the US Food and Drug Administration has recommended that such devices be evaluated for corrosion resistance after the devices have been fatigue tested in situations where significant micromotion can lead to fretting damage. Three common alloys that cardiovascular implants are made from [MP35N cobalt chromium (MP35N), electropolished nitinol (EP NiTi), and 316LVM stainless steel (316LVM)] were selected for this study. In order to evaluate the effect of wire fretting on the pitting corrosion susceptibility of these medical alloys, small and large fretting scar conditions of each alloy fretting against itself, and the other alloys in phosphate buffered saline (PBS) at 37°C were tested per ASTM F2129 and compared against as received or PBS immersed control specimens. Although the general trend observed was that fretting damage significantly lowered the rest potential (E r ) of these specimens (p  0.05) and hence did not affect the susceptibility to pitting corrosion. In summary, our results demonstrate that fretting damage in PBS alone is not sufficient to cause increased susceptibility to pitting corrosion in the three common alloys investigated. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2487-2494, 2017. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

  9. Microstructure, a limiting parameter for determining the engineering range of compositions for light alloys: The Al-Cu-Si system

    Energy Technology Data Exchange (ETDEWEB)

    Plaza, D.; Pero-Sanz, J.A. [Univ. Politecnica, Madrid (Spain); Asensio, J.; Verdeja, J.I. [Univ. de Oviedo (Spain)

    1998-03-01

    Twelve as-cast alloys of the Al-Cu-Si ternary system were investigated. In all the cases, the microstructural phases observed were: {alpha} solid solution of Cu and Si in Al, CuAl{sub 2} ({theta} phase), and silicon crystals. The morphology and distribution of the {theta} and Si brittle constituents limit the percentages of Cu and Si added in the composition ranges of these commercial alloys.

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

    OpenAIRE

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

    2015-01-01

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

  11. Understanding the vapor-liquid-solid growth and composition of ternary III-V nanowires and nanowire heterostructures

    Science.gov (United States)

    Dubrovskii, V. G.

    2017-11-01

    Based on the recent achievements in vapor-liquid-solid (VLS) synthesis, characterization and modeling of ternary III-V nanowires and axial heterostructures within such nanowires, we try to understand the major trends in their compositional evolution from a general theoretical perspective. Clearly, the VLS growth of ternary materials is much more complex than in standard vapor-solid epitaxy techniques, and even maintaining the necessary control over the composition of steady-state ternary nanowires is far from straightforward. On the other hand, VLS nanowires offer otherwise unattainable material combinations without introducing structural defects and hence are very promising for next-generation optoelectronic devices, in particular those integrated with a silicon electronic platform. In this review, we consider two main problems. First, we show how and by means of which parameters the steady-state composition of Au-catalyzed or self-catalyzed ternary III-V nanowires can be tuned to a desired value and why it is generally different from the vapor composition. Second, we present some experimental data and modeling results for the interfacial abruptness across axial nanowire heterostructures, both in Au-catalyzed and self-catalyzed VLS growth methods. Refined modeling allows us to formulate some general growth recipes for suppressing the unwanted reservoir effect in the droplet and sharpening the nanowire heterojunctions. We consider and refine two approaches developed to date, namely the regular crystallization model for a liquid alloy with a critical size of only one III-V pair at high supersaturations or classical binary nucleation theory with a macroscopic critical nucleus at modest supersaturations.

  12. Corrosion behavior of palladium-silver-copper alloys in model saliva.

    Science.gov (United States)

    Joska, Ludek; Poddana, Marcela; Leitner, Jindrich

    2008-08-01

    Palladium-silver system alloyed with other metals represents one of possible material choices in prosthetics. Its corrosion properties are influenced by minority components added in order to obtain the properties required for stomatological purposes. The objective of this work was to ascertain the influence of copper on the corrosion mechanism of palladium-silver alloys. Corrosion properties of four palladium-silver-copper alloys were compared with the behavior of the palladium-silver binary system. Standard electrochemical measurements in a model saliva solution were complemented with an XPS analysis of the specimens surface. Experimental data were compared with the results of thermodynamic analysis. The foregoing study revealed formation of a saline layer of insoluble silver compounds as the dominant feature of the corrosion mechanism in a binary system. This process is suppressed in ternary alloys where electrochemical reactions of copper take place on the alloy-electrolyte phase boundary leading to the formation of a layer based on copper oxides. The alloying of the palladium-silver binary system with copper results in an important change in the corrosion behavior of ternary alloys. A change in the mechanism of interaction with the environment leads to susceptibility to non-uniform corrosion.

  13. Formation and thermal stability of amorphous Ti-Si-C alloys

    Energy Technology Data Exchange (ETDEWEB)

    Naka, M. [Joining and Welding Research Inst., Osaka (Japan); Sakai, H. [Osaka University, Osaka 565 (Japan); Maeda, M. [Joining and Welding Research Inst., Osaka (Japan); Mori, H. [Research Center for Ultra-High Voltage Electronmicroscopy, Osaka University, Osaka 565 (Japan)

    1997-06-15

    The crystallization behavior of Ti-Si-C ternary amorphous alloys sputtered in low-pressure argon was investigated by measuring differential scanning calorimetry (DSC) curves. The crystallized microstructures of Ti-Si-C amorphous alloys were observed by in-situ heating in a hot stage of an electron microscope. Ti-46at.%Si-32at.%C amorphous alloy crystallizes to fine grains composed of {beta}-SiC and TiSi{sub 2}. Ti-14at.%Si-20at.%C amorphous alloy crystallizes to fine grains composed of TiC and Ti{sub 5}Si{sub 3}. Although the carbon improves the thermal stability of the Ti-Si-C ternary alloys, the silicon degrades the thermal stability of the alloys. The amorphous alloys containing compositions corresponding to carbosilicide or carbide such as Ti{sub 5}Si{sub 3}C{sub x}, Ti{sub 3}SiC{sub 2} or SiC possess high thermal stability and high hardness values. (orig.)

  14. Characterization of microstructural, mechanical and thermophysical properties of Th-52U alloy

    Energy Technology Data Exchange (ETDEWEB)

    Das, Santanu, E-mail: reachoutsantanu@gmail.com [Integrated Fuel Fabrication Facility, Bhabha Atomic Research Centre, Mumbai (India); Kaity, S. [Radiometallurgy Division, Bhabha Atomic Research Centre, Mumbai (India); Kumar, R. [Uranium Extraction Division, Bhabha Atomic Research Centre, Mumbai (India); Banerjee, J. [Radiometallurgy Division, Bhabha Atomic Research Centre, Mumbai (India); Roy, S.B. [Chemical Engineering Group, Bhabha Atomic Research Centre, Mumbai (India); Chaudhari, G.P.; Daniel, B.S.S. [Indian Institute of Technology Roorkee, Roorkee (India)

    2016-11-15

    Th-52 wt.% U alloy has a microstructure featuring interspersed networks of uranium rich and thorium rich phases. Room temperature hardness of the alloy is more than twice that of unalloyed thorium. The alloy age hardens (550 °C) only slightly (peak hardness/hardness of solution heated and quenched = 1.05). Room temperature thermal conductivity (25.6 W m{sup −1} {sup °}C{sup −1}) is close to that of uranium and most of the binary and ternary metallic alloy fuel materials. Average linear coefficient of thermal expansion (CTE) of Th-52 wt.% U alloy [11.2 × 10{sup −06} °C{sup −1} (27–290 °C) and 16.75 × 10{sup −06} °C{sup −1} (27–600 °C)] are comparable with that of many metallic alloy fuel candidates. Th-52 wt.% U alloy with non-age hardenable microstructure, appreciable thermal conductivity, moderate thermal expansion may find metallic fuel applications in nuclear reactors. - Highlights: • Th-52U alloy consists of continuous, interspersed network of Th-rich and U-rich phases. • This monotectic alloy composition shows negligible age hardening but fast kinetics. • Average linear CTE (27–600 {sup °}C) (16.7 × 10{sup −6} °C{sup -1}) of Th-52U alloy is comparable with that of other metallic fuels. • λ{sub RT} (25.6 W m{sup −1} °C{sup −1}) is comparable with that of most of the binary and ternary alloy fuels.

  15. Positron annihilation lifetime study of interfaces in ternary polymer blends

    Science.gov (United States)

    Meghala, D.; Ramya, P.; Pasang, T.; Raj, J. M.; Ranganathaiah, C.; Williams, J. F.

    2013-06-01

    A new method based on positron lifetime spectroscopy is developed to characterize individual interfaces in ternary polymer blends and hence determine the composition dependent miscibility level. The method owes its origin to the Kirkwood-Risemann-Zimm (KRZ) model for the evaluation of the hydrodynamic interaction parameters (αij) which was used successfully for a binary blend with a single interface. The model was revised for the present work for ternary polymer blends to account for three interfaces. The efficacy of this method is shown for two ternary blends namely poly(styrene-co-acrylonitrile)/poly (ethylene-co-vinylacetate)/poly(vinyl chloride) (SAN/EVA/PVC) and polycaprolactone /poly(styrene-co-acrylonitrile)/poly(vinyl chloride) (PCL/SAN/PVC) at different compositions. An effective hydrodynamic interaction parameter, αeff, was introduced to predict the overall miscibility of ternary blends.

  16. Orthodontic silver brazing alloys.

    Science.gov (United States)

    Brockhurst, P J; Pham, H L

    1989-10-01

    Orthodontic silver brazing alloys suffer from the presence of cadmium, excessive flow temperatures, and crevice corrosion on stainless steel. Seven alloys were examined. Two alloys contained cadmium. The lowest flow temperature observed was 629 degrees C for a cadmium alloy and 651 degrees C for two cadmium free alloys. Three alloys had corrosion resistance superior to the other solders. Addition of low melting temperature elements gallium and indium reduced flow temperature in some cases but produced brittleness in the brazing alloy.

  17. Subarrayed Antenna Array Synthesis Using Ternary Adjusting Method

    Directory of Open Access Journals (Sweden)

    Guolong He

    2014-01-01

    Full Text Available Ternary adjusting method is proposed and combined with particle swarm optimization (PSO algorithm for subarrayed antenna array synthesis. Ternary variables are introduced to represent element adjustments between adjacent subarrays. Compared to previous methods, rounding-off operations are not required any longer, and the equation constraint of the fixed total element number is also removed, which effectively reduces the complexity of implementation while obtaining improved topology exploration capability simultaneously.

  18. A new look at biomedical Ti-based shape memory alloys.

    Science.gov (United States)

    Biesiekierski, Arne; Wang, James; Gepreel, Mohamed Abdel-Hady; Wen, Cuie

    2012-05-01

    Shape memory alloys (SMAs) are materials that exhibit a distinct thermomechanical coupling, one that gives rise to a wide variety of applications across a broad range of fields. One of the most successful roles is in the construction of novel medical implants. Unfortunately, concerns have been raised about the biocompatibility of the most popular SMA, nitinol (NiTi), due to the known toxic, allergenic and carcinogenic properties of nickel. Given the unique capabilities of SMAs, it is apparent that there is a need for a new class of alloys - alloys that exhibit the full range of shape memory abilities yet are also free of any undesirable side effects. This article reviews the literature surrounding SMAs and identifies the metals Ti, Au, Sn, Ta, Nb, Ru and Zr as candidates for the production of thoroughly biocompatible SMAs. Hf and Re are also promising, though more research is necessary before a definitive statement can be made. Further, the Ti-(Ta,Nb)-(Zr,Hf) alloy system is particularly suited for orthopaedic implants due to a reduced Young's modulus. However, concerns over this system's shape memory properties exist, and should be taken into consideration. Alternate alloy systems that demonstrate higher bulk moduli may still be considered, however, if they are formed into a porous structure. Due to the nature of the alloying components, blended elemental powder metallurgy is recommended for the manufacture of these alloys, particularly due to the ease with which it may be adapted to the formation of porous alloys. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  19. On the importance of thermodynamic investigations for the re-assessment of selected ternary Fe-base systems

    Science.gov (United States)

    Presoly, P.; Bernhard, C.

    2016-07-01

    Reliable thermodynamic data are essential for the design and the production of new alloying systems. Particularly, the knowledge of the high-temperature phase transformations (TLiquid, TSolid, TPerit, Tγ→δ) are important for the solidification and the further processing. Investigations of selected commercial Dual-Phase, TRIP and high-Mn TWIP steels by DTA/DSC measurements show that the experimental results differ significantly from the calculation results of thermodynamic databases with respect to the phase transformation temperature and sequence. Based on these findings, it is very important to identify the defective subsystems of complex alloys in order to optimise the thermodynamic databases. In order to verify a quaternary system, e.g. the Fe-C-Si-Mn system, it is important to check the corresponding ternary subsystems. This was performed by DSC measurements of selected model alloys. By doing so, it was found that in Si- and Mn-alloyed Dual-Phase steels the thermodynamic description of the Fe-Si-Mn system is currently inadequate. This is a very important result, since all new designed steel grades for the automotive industry are based on a Fe-C-Si-Mn matrix.

  20. Charge distribution in the ternary fragmentation of {sup 252}Cf

    Energy Technology Data Exchange (ETDEWEB)

    Senthil Kannan, M.T.; Balasubramaniam, M. [Bharathiar University, Department of Physics, Coimbatore (India)

    2017-08-15

    We present here, for the first time, a study on ternary fragmentation charge distribution of {sup 252}Cf using the convolution integral method and the statistical theory. The charge distribution for all possible charge combinations of a ternary breakup are grouped as a bin containing different mass partitions. Different bins corresponding to various third fragments with mass numbers from A{sub 3} = 16 to 84 are identified with the available experimental masses. The corresponding potential energy surfaces are calculated using the three cluster model for the two arrangements A{sub 1} + A{sub 2} + A{sub 3} and A{sub 1} + A{sub 3} + A{sub 2}. The ternary fragmentation yield values are calculated for the ternary combination from each bin possessing minimum potential energy. The yields of the resulting ternary combinations as a function of the charge numbers of the three fragments are analyzed for both the arrangements. The calculations are carried out at different excitation energies of the parent nucleus. For each excitation energy the temperature of the three fragments are iteratively computed conserving the total energy. The distribution of fragment temperatures corresponding to different excitation energies for some fixed third fragments are discussed. The presence of the closed shell nucleus Sn in the favourable ternary fragmentation is highlighted. (orig.)

  1. Impact of ternary blends of biodiesel on diesel engine performance

    Directory of Open Access Journals (Sweden)

    Prem Kumar

    2016-06-01

    Full Text Available The Pongamia and waste cooking oils are the main non edible oils for biodiesel production in India. The aim of the present work is to evaluate the fuel properties and investigate the impact on engine performance using Pongamia and waste cooking biodiesel and their ternary blend with diesel. The investigation of the fuel properties shows that Pongamia biodiesel and waste cooking biodiesel have poor cold flow property. This will lead to starting problem in the engine operation. To overcome this problem the ternary blends of diesel, waste cooking biodiesel and Pongamia biodiesel are prepared. The cloud and pour point for ternary blend, (WCB20:PB20:D60 were found to be 7 °C and 6.5 °C which are comparable to cloud and pour point of diesel 6 °C and 5 °C, respectively. The result of the test showed that brake specific fuel consumption for Pongamia biodiesel and waste cooking biodiesel is higher than ternary blend, (WCB20:PB20:D60 due to their lower energy content. The brake thermal efficiency of ternary blend and diesel is comparable while the Pongamia and waste cooking biodiesel have low efficiency. The result of investigation showed that ternary blend can be developed as alternate fuel.

  2. Magnesium and related low alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, J.; Caillat, R.; Darras, R. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1959-07-01

    In the first part the authors examine the comparative corrosion of commercial magnesium, of a magnesium-zirconium alloy (0,4 per cent {<=} Zr {<=} 0,7 per cent) of a ternary magnesium-zinc-zirconium alloy (0,8 per cent {<=} Zn {<=} 1,2 per cent) and of english 'Magnox type' alloys, in dry carbon dioxide-free air, in damp carbon dioxide-free air, and in dry and damp carbon dioxide, at temperatures from 300 to 600 deg. C. In the second part the structural stability of these materials is studied after annealings, of 10 to 1000 hours at 300 to 450 deg. C. Variations in grain after these heat treatments and mechanical stretching properties at room temperature are presented. Finally various creep rate and life time diagrams are given for these materials, for temperatures ranging from 300 to 450 deg. C. (author) [French] Dans une premiere partie les auteurs etudient la corrosion comparee du magnesium commercial, d'un alliage magnesium-zirconium (0,4 pour cent {<=} Zr {<=} 0,7 pour cent), d'un alliage ternaire magnesium-zinc-zirconium (0,8 pour cent {<=} Zn {<=} 1,2 pour cent), et d'alliages anglais 'type Magnox', dans l'air sec decarbonate, l'air humide decarbonate, le gaz carbonique sec et humide a des temperatures de 300 a 600 deg. C. Dans une seconde partie, est etudiee la stabilite structurale de ces materiaux apres des recuits de 300 a 450 deg. C, et de 10 a 1000 heures. Sont presentees les variations, apres ces traitements thermiques, de la grosseur du grain, et des caracteristiques mecaniques de traction a la temperature ambiante. Enfin, quelques diagrammes de vitesse de fluage et de durees de vie sont presentes sur ces materiaux pour des temperatures variant entre 300 et 450 deg. C. (auteur)

  3. Maxwell-Stefan diffusion coefficient estimation for ternary systems: an ideal ternary alcohol system.

    Science.gov (United States)

    Allie-Ebrahim, Tariq; Zhu, Qingyu; Bräuer, Pierre; Moggridge, Geoff D; D'Agostino, Carmine

    2017-06-21

    The Maxwell-Stefan model is a popular diffusion model originally developed to model diffusion of gases, which can be considered thermodynamically ideal mixtures, although its application has been extended to model diffusion in non-ideal liquid mixtures as well. A drawback of the model is that it requires the Maxwell-Stefan diffusion coefficients, which are not based on measurable quantities but they have to be estimated. As a result, numerous estimation methods, such as the Darken model, have been proposed to estimate these diffusion coefficients. However, the Darken model was derived, and is only well defined, for binary systems. This model has been extended to ternary systems according to two proposed forms, one by R. Krishna and J. M. van Baten, Ind. Eng. Chem. Res., 2005, 44, 6939-6947 and the other by X. Liu, T. J. H. Vlugt and A. Bardow, Ind. Eng. Chem. Res., 2011, 50, 10350-10358. In this paper, the two forms have been analysed against the ideal ternary system of methanol/butan-1-ol/propan-1-ol and using experimental values of self-diffusion coefficients. In particular, using pulsed gradient stimulated echo nuclear magnetic resonance (PGSTE-NMR) we have measured the self-diffusion coefficients in various methanol/butan-1-ol/propan-1-ol mixtures. The experimental values of self-diffusion coefficients were then used as the input data required for the Darken model. The predictions of the two proposed multicomponent forms of this model were then compared to experimental values of mutual diffusion coefficients for the ideal alcohol ternary system. This experimental-based approach showed that the Liu's model gives better predictions compared to that of Krishna and van Baten, although it was only accurate to within 26%. Nonetheless, the multicomponent Darken model in conjunction with self-diffusion measurements from PGSTE-NMR represents an attractive method for a rapid estimation of mutual diffusion in multicomponent systems, especially when compared to exhaustive

  4. USE OF COVERED SELF-EXPANDABLE NITINOL STENT FOR ANASTOMOTIC BILIARY STRUCTURE MANAGEMENT AFTER LIVER TRANSPLANTATION: THE FIRST EXPERIENCE

    Directory of Open Access Journals (Sweden)

    M. N. Kornilov

    2013-01-01

    Full Text Available Aim. The aim of this study focuses on the first experience with self-expandable stents, analysis of its efficacy and safety in the treatment of anastomotic strictures after liver transplantation. Materials and methods. There’re 136 liver transplantations performed from 2004 till 2012. To correct anastomotic strictures we’ve used only the self-expandable coated nitinol stent. We performed stenting in 7 recipient. Result. In 131 liver transplant recipients incidence of biliary strictures has been 5.3%. All of 5 patients have been managed by retrograde or antegrade way. Conclusion. Our first experience demonstrate efficacy and safety of the used tecniques up to 24 months. The analysis of more long-term results is required. 

  5. Evolution of Ternary AuAgPd Nanoparticles by the Control of Temperature, Thickness, and Tri-Layer

    Directory of Open Access Journals (Sweden)

    Sundar Kunwar

    2017-11-01

    Full Text Available Metallic alloy nanoparticles (NPs possess great potential to enhance the optical, electronic, chemical, and magnetic properties for various applications by the control of morphology and elemental composition. This work presents the fabrication of ternary AuAgPd alloy nanostructures on sapphire (0001 via the solid-state dewetting of sputter-deposited tri-metallic layers. Based on the systematic control of temperature, thickness, and deposition order of tri-layers, the composite AuAgPd alloy nanoparticles (NPs with various shape, size, and density are demonstrated. The metallic tri-layers exhibit various stages of dewetting based on the increasing growth temperatures between 400 and 900 °C at 15 nm tri-layer film thickness. Specifically, the nucleation of tiny voids and hillocks, void coalescence, the growth and isolated nanoparticle formation, and the shape transformation with Ag sublimation are observed. With the reduced film thickness (6 nm, tiny alloy NPs with improved structural uniformity and spatial arrangement are obtained due to enhanced dewetting. The growth trend of alloy NPs is drastically altered by changing the deposition order of metallic tri-layers. The overall evolution is governed by the surface diffusion and inter-mixing of metallic atoms, Rayleigh-like instability, surface and interface energy minimization, and equilibrium state of the system. The UV-VIS-NIR reflectance spectra reveal the formation of an absorption band and reflectance maxima at specific wavelengths based on the morphology and composition of AuAgPd alloy NPs. In addition, Raman spectra analysis shows the modulation of intensity and peak position of natural vibration modes of sapphire (0001.

  6. Effect of composition on the structure and properties of Ti-Co-Cr alloys

    Directory of Open Access Journals (Sweden)

    T. Matković

    2010-01-01

    Full Text Available The present work is a study of six as-cast Ti-Co-Cr alloys in the Ti-rich region with the purpose of examining the possibility of obtaining a new β-type Ti-alloys. Two experimental alloys Ti80Co10Cr10 and Ti70Co10Cr20 are nearly single-phases and are identified as bcc β-Ti phase. They also display the lowest hardness values and the best corrosion properties. The present study indicates that the region of biomedically-acceptable ternary Ti-rich alloys is situated within lower concentrations of alloying elements, i.e. about 10 at.% Co and 20 at. % Cr.

  7. Acceptance Criteria for Corrosion Resistance of Medical Devices: Statistical Analysis of Nitinol Pitting in In Vivo Environments

    Science.gov (United States)

    Eiselstein, Lawrence E.; Steffey, Duane; Nissan, Andrew; Corlett, Nigel; Dugnani, Roberto; Kus, Esra; Stewart, Sarah G.

    2009-08-01

    ASTM F 2129 test method nor the FDA provides any guidance as to what constitutes an acceptance criterion for the corrosion resistance of implantable medical devices. Neither provide any guidance on how many samples to test or how to handle censored data, i.e. datasets where there are only a few tests that breakdown. The development of both a statistically valid acceptance criterion for corrosion resistance and a method of evaluation would be of significant benefit to the medical device community. This study of 420 nitinol cyclic polarization tests, which builds on previous research that was presented at SMST 2007, investigates the effect of long-term exposure to simulated in vivo environments with differing degrees of aeration. This was accomplished by pre-exposing electropolished (EP) nitinol to phosphate buffered saline (PBS) at 37 °C that had been sparged with either ultra high purity nitrogen or laboratory air. Immersion times ranged from 1 h up to 30 days. A total of 290 EP samples were tested in order to obtain a reasonable number of samples with breakdown, i.e. pitted. In addition, a total of 130 mechanical polished (MP) samples were also analyzed. This data allow us to test our statistical model that was presented at SMST 2007. This model takes into account the probability of breakdown per unit of exposed surface area and, if breakdown occurs, predicts the probability that E b - E r is greater than some threshold value. Aerated PBS environments were found to have a large influence on the margin of safety against pitting in vivo. Statistical methods for treating highly right censored pitting data are presented.

  8. Two-layer synchronized ternary quantum-dot cellular automata wire crossings

    Science.gov (United States)

    2012-01-01

    Quantum-dot cellular automata are an interesting nanoscale computing paradigm. The introduction of the ternary quantum-dot cell enabled ternary computing, and with the recent development of a ternary functionally complete set of elementary logic primitives and the ternary memorizing cell design of complex processing structures is becoming feasible. The specific nature of the ternary quantum-dot cell makes wire crossings one of the most problematic areas of ternary quantum-dot cellular automata circuit design. We hereby present a two-layer wire crossing that uses a specific clocking scheme, which ensures the crossed wires have the same effective delay. PMID:22507371

  9. Contrasting performance of donor-acceptor copolymer pairs in ternary blend solar cells and two-acceptor copolymers in binary blend solar cells.

    Science.gov (United States)

    Khlyabich, Petr P; Rudenko, Andrey E; Burkhart, Beate; Thompson, Barry C

    2015-02-04

    Here two contrasting approaches to polymer-fullerene solar cells are compared. In the first approach, two distinct semi-random donor-acceptor copolymers are blended with phenyl-C61-butyric acid methyl ester (PC61BM) to form ternary blend solar cells. The two poly(3-hexylthiophene)-based polymers contain either the acceptor thienopyrroledione (TPD) or diketopyrrolopyrrole (DPP). In the second approach, semi-random donor-acceptor copolymers containing both TPD and DPP acceptors in the same polymer backbone, termed two-acceptor polymers, are blended with PC61BM to give binary blend solar cells. The two approaches result in bulk heterojunction solar cells that have the same molecular active-layer components but differ in the manner in which these molecular components are mixed, either by physical mixing (ternary blend) or chemical "mixing" in the two-acceptor (binary blend) case. Optical properties and photon-to-electron conversion efficiencies of the binary and ternary blends were found to have similar features and were described as a linear combination of the individual components. At the same time, significant differences were observed in the open-circuit voltage (Voc) behaviors of binary and ternary blend solar cells. While in case of two-acceptor polymers, the Voc was found to be in the range of 0.495-0.552 V, ternary blend solar cells showed behavior inherent to organic alloy formation, displaying an intermediate, composition-dependent and tunable Voc in the range from 0.582 to 0.684 V, significantly exceeding the values achieved in the two-acceptor containing binary blend solar cells. Despite the differences between the physical and chemical mixing approaches, both pathways provided solar cells with similar power conversion efficiencies, highlighting the advantages of both pathways toward highly efficient organic solar cells.

  10. Nanoporous PtFe alloys as highly active and durable electrocatalysts for oxygen reduction reaction

    Science.gov (United States)

    Duan, Huimei; Hao, Qin; Xu, Caixia

    2014-12-01

    Nanoporous PtFe alloys with two different bimetallic ratios are fabricated by selectively dealloying PtFeAl ternary alloys, characterized by nanoscaled bicontinuous network skeleton with interconnected hollow channels extending in all three dimensions. The reactive components in PtFeAl ternary alloy were sequentially leached out in a highly controllable manner, generating nanoporous architecture with different bimetallic ratios and the typical ligament size as small as 5 nm. These nanoporous PtFe alloys exhibit much enhanced electrocatalytic activity for oxygen reduction reaction compared with the PtFe/C and Pt/C catalysts. The specific and mass activities for oxygen reduction follow the order of nanoporous Pt75Fe25 > nanoporous Pt55Fe45 > PtFe/C > Pt/C. In the absence of any catalyst support, the structure stability of nanoporous PtFe alloys is greatly enhanced with less loss of the electrochemical surface area and the oxygen reduction activity upon long-term potential scan tests compared with PtFe/C and Pt/C catalysts. The as-made nanoporous PtFe alloys thus hold great application potential as promising cathode electrocatalyst in proton exchange membrane fuel cells with the advantages of easy preparation along with superior oxygen reduction activity and durability.

  11. The Effect of Cu and Cr on Clustering and Precipitation in Al-Mg-Si Alloys

    Science.gov (United States)

    Liang, Zeqin; Chang, Cynthia Sin Ting; Banhart, John; Hirsch, Jürgen

    A group of alloys based on pure ternary Al-0.4 wt.%Mg-1.0 wt.%Si are used to study the effect of Cu and Cr on clustering and precipitation in Al-Mg-Si alloys. Differential Scanning Calorimetry (DSC) is performed for samples naturally aged for different times after solution heat treatment and ice water quenching. Three clustering processes are observed in all the alloys. The fundamental clustering sequence does not change by additional elements. However, the Cu containing alloy shows less clustering and the first clustering event is hindered. Kissinger analysis reveals that the 2nd and 3rd processes have very similar effective activation energies. Therefore, a model incorporating only two independent reactions is used to obtain kinetic parameters. It is found that the first clustering process starts with a low effective activation energy of 50 kJ/mol and has a mechanism similar to mixed nucleation while the latter two processes are governed by a higher activation energy of 79 kJ/mol and have a mechanism similar to particle growth. During precipitation, the Cr containing alloy shows a similar precipitation heat signal in DSC as the pure ternary, thus having negligible effect on precipitation. On the other hand, the formation of β″ is less dominant in the Cu-containing alloy while precipitation of other phases before reaching the peak-aged condition is possible.

  12. Phase Equilibria in the Fe-Mo-Ti Ternary System at 1173 K (900 °C) and 1023 K (750 °C)

    Science.gov (United States)

    Knowles, A. J.; Jones, N. G.; Jones, C. N.; Stone, H. J.

    2017-09-01

    Alloys with fine-scale eutectic microstructures comprising Ti-based A2 and TiFe B2 phases have been shown to have excellent mechanical properties. In this study, the potential of alloys with further refined A2-B2 microstructures formed through solid-state precipitation has been explored by analyzing a series of six alloys within the Fe-Mo-Ti ternary system. Partial isothermal sections of this system at 1173 K (900 °C) and 1023 K (750 °C) were constructed, from which the ternary solubility limits of the A2 (Ti, Mo), B2 TiFe, D85 Fe7Mo6, and C14 Fe2Ti phases were determined. With these data, the change in solubility of Fe in the A2 phase with temperature, which provides the driving force for precipitation of B2 TiFe, was determined and used to predict the maximum potential volume fraction of B2 TiFe precipitates that may be formed in an A2 (Ti, Mo) matrix.

  13. New Theoretical Technique Developed for Predicting the Stability of Alloys

    Science.gov (United States)

    1996-01-01

    When alloys are being designed for aeronautical and other applications, a substantial experimental effort is necessary to make incremental changes in the desired alloy properties. A scheme to narrow the field to the most promising candidates would substantially reduce the high cost of this experimental screening. Such a method for determining alloy properties, called the BFS (Bozzolo, Ferrante, and Smith) method, has been developed at the NASA Lewis Research Center. This method was used to calculate the thermal stability and mechanical strength of 200 alloys of Ni3Al, with Cu and Au impurities forming ternary and quaternary compounds. With recent advances in the method, almost any metallic impurity and crystal structure can be addressed. In addition, thermal effects can be addressed with Monte Carlo techniques. At present, an experimental program is in progress to verify these results. The method identified a small number of the most promising candidates from the 200 alloys with the largest negative heat of formation and the highest bulk modulus. This calculation required only 5 min of CPU time on a VAX computer. It is clear that semi-empirical methods have achieved the level of development and reliability to warrant examining this new approach to the problem of alloy design. The present work was meant to demonstrate, perhaps in a rather simple way, this power. This type of application of atomistic simulation methods can narrow the gap and improve the feedback between theoretical predictions and laboratory experimentation.

  14. Liquid-liquid equilibria for ternary polymer mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Suk Yung [Division of Chemical Engineering and Molecular Thermodynamics Laboratory, Hanyang University, Seoul 133-791 (Korea, Republic of); Bae, Young Chan, E-mail: ycbae@hanyang.ac.kr [Division of Chemical Engineering and Molecular Thermodynamics Laboratory, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2011-01-24

    Graphical abstract: We developed a molecular thermodynamic model for multicomponent systems and discribed the phase equilibrium for ternary polymer mixtures by using the model parameters obtained from the binary systems. Research highlights: {yields} Model parameters were obtained from the binary systems. {yields} The obtained parameters were directly used to predict the ternary data. {yields} The undetermined parameters were used to correlate the ternary data. {yields} The proposed model agreed well with the experimental data. - Abstract: A molecular thermodynamic model for multicomponent systems based on a closed-packed lattice model is presented based on two contributions; entropy and energy contribution. The calculated liquid-liquid equilibria of ternary chainlike mixtures agreed with Monte Carlo simulation results. The proposed model can satisfactorily predict Types 0, 1, 2 and 3 phase separations of the Treybal classification. The model parameters obtained from the binary systems were used to directly predict real ternary systems and the calculated results correlated well with experimental data using few adjustable parameters. Specific interactions in associated binary systems were considered using a secondary lattice.

  15. Effects of Palladium Content, Quaternary Alloying, and Thermomechanical Processing on the Behavior of Ni-Ti-Pd Shape Memory Alloys for Actuator Applications

    Science.gov (United States)

    Bigelow, Glen

    2008-01-01

    The need for compact, solid-state actuation systems for use in the aerospace, automotive, and other transportation industries is currently driving research in high-temperature shape memory alloys (HTSMA) having transformation temperatures above 100 C. One of the basic high temperature systems under investigation to fill this need is NiTiPd. Prior work on this alloy system has focused on phase transformations and respective temperatures, no-load shape memory behavior (strain recovery), and tensile behavior for selected alloys. In addition, a few tests have been done to determine the effect of boron additions and thermomechanical treatment on the aforementioned properties. The main properties that affect the performance of a solid state actuator, namely work output, transformation strain, and permanent deformation during thermal cycling under load have mainly been neglected. There is also no consistent data representing the mechanical behavior of this alloy system over a broad range of compositions. For this thesis, ternary NiTiPd alloys containing 15 to 46 at.% palladium were processed and the transformation temperatures, basic tensile properties, and work characteristics determined. However, testing reveals that at higher levels of alloying addition, the benefit of increased transformation temperature begins to be offset by lowered work output and permanent deformation or "walking" of the alloy during thermal cycling under load. In response to this dilemma, NiTiPd alloys have been further alloyed with gold, platinum, and hafnium additions to solid solution strengthen the martensite and parent austenite phases in order to improve the thermomechanical behavior of these materials. The tensile properties, work behavior, and dimensional stability during repeated thermal cycling under load for the ternary and quaternary alloys were compared and discussed. In addition, the benefits of more advanced thermomechanical processing or training on the dimensional stability of

  16. Monte Carlo Simulation of Alloy Design Techniques: Fracture and Welding Studied Using the BFS Method for Alloys

    Science.gov (United States)

    Bozzolo, Guillermo H.; Good, Brian; Noebe, Ronald D.; Honecy, Frank; Abel, Phillip

    1999-01-01

    Large-scale simulations of dynamic processes at the atomic level have developed into one of the main areas of work in computational materials science. Until recently, severe computational restrictions, as well as the lack of accurate methods for calculating the energetics, resulted in slower growth in the area than that required by current alloy design programs. The Computational Materials Group at the NASA Lewis Research Center is devoted to the development of powerful, accurate, economical tools to aid in alloy design. These include the BFS (Bozzolo, Ferrante, and Smith) method for alloys (ref. 1) and the development of dedicated software for large-scale simulations based on Monte Carlo- Metropolis numerical techniques, as well as state-of-the-art visualization methods. Our previous effort linking theoretical and computational modeling resulted in the successful prediction of the microstructure of a five-element intermetallic alloy, in excellent agreement with experimental results (refs. 2 and 3). This effort also produced a complete description of the role of alloying additions in intermetallic binary, ternary, and higher order alloys (ref. 4).

  17. Two-year Clinical Outcomes Post Implantation of Epic(TM) Self-Expanding Nitinol Stents for the Aortoiliac Occlusive Disease in Patients with Peripheral Arterial Disease.

    Science.gov (United States)

    Tsujimura, Takuya; Iida, Osamu; Fujita, Masashi; Masuda, Masaharu; Okamoto, Shin; Ishihara, Takayuki; Nanto, Kiyonori; Kanda, Takashi; Okuno, Shota; Matsuda, Yasuhiro; Fujihara, Masahiko; Yokoi, Yoshiaki; Mano, Toshiaki

    2017-10-05

    We investigated 2-year clinical outcomes after implantaton of Epic(TM) self-expanding nitinol stents for patients with peripheral artery disease (PAD) due to the aortoiliac occlusive disease (AIOD). This study was a multicenter and retrospective study. From February 2013 through October 2014, 292 lesions (chronic total occlusion, 21%; TASC Ⅱ C/D, 35%) in 217 consecutive patients (74±8 years; male, 81%; diabetes mellitus, 47%; dialysis, 21%; critical limb ischemia, 29%) who had undergone endovascular therapy (EVT) with Epic(TM) self-expanding nitinol stents for PAD with AIOD were analyzed. The primary endpoints were 2-year primary patency and target lesion revascularization (TLR)-free rate. The primary patency and freedom from TLR were determined by Kaplan-Meier analysis. Additionally, predictors for loss of patency were estimated by Cox proportional hazard model. The mean follow-up duration was 19.1±8.5 months. Primary patency was 87.3% at 2 years. Freedom from TLR rate was 94.1% at 2 years. Multivariate analysis revealed that the presence of diabetes mellitus was associated with a loss of patency. The Epic(TM) self-expanding nitinol stent was demonstrated to be safe and effectivene for AIOD when tested for two years in patients with PAD.

  18. Microstructural characterization of Mg–Al–Sr alloys

    Directory of Open Access Journals (Sweden)

    M. Aljarrah et al

    2007-01-01

    Full Text Available The microstructural details of fourteen Mg–Al–Sr alloys were investigated in the as-cast form by a combination of scanning electron microscopy/energy dispersive spectrometer (SEM/EDS analysis and quantitative electron probe microanalysis (EPMA. The heat transfer method coupled with the DSC measurement has been utilized to determine the solidification curves of the alloys. The morphology and the chemical composition of the phases were characterized. The microstructure of the alloys is primarily dominated by (Mg and (Al4Sr. In the present investigation, ternary solid solubility of three binary compounds extended into the ternary system has been reported and denoted as: (Al4Sr, (Mg17Sr2 and (Mg38Sr9. The (Al4Sr phase is a substitutional solid solution represented by MgxAl4−xSr and has a plate-like structure. The maximum solubility of Al in Mg17Sr2 was found to be 21.3 at%. It was also observed that Mg38Sr9 dissolved 12.5 at% Al.

  19. Structure and anelasticity of Fe{sub 3}Ga and Fe{sub 3}(Ga,Al) type alloys

    Energy Technology Data Exchange (ETDEWEB)

    Golovin, I.S., E-mail: i.golovin@misis.ru [Department of Physical Metallurgy of Non-Ferrous Metals, National University of Science and Technology “MISIS”, Leninsky ave. 4, Moscow 117936 (Russian Federation); Palacheva, V.V.; Bazlov, A.I. [Department of Physical Metallurgy of Non-Ferrous Metals, National University of Science and Technology “MISIS”, Leninsky ave. 4, Moscow 117936 (Russian Federation); Cifre, J. [Serveis Cientificotecnics, Universitat de les Illes Balears, Ctra. deValldemossa, km. 7.5, E-07122 Palma de Mallorca (Spain); Pons, J. [Dept. de Fisica, Universitat de les Illes Balears, Ctra. deValldemossa, km. 7.5, E-07122 Palma de Mallorca (Spain)

    2015-09-25

    Highlights: • The A2 to D0{sub 3} transition in quenched Fe–27Ga takes place at heating from 150 to 300 °C. • The L1{sub 2} phase appears after incubation period at 350 °C and above. • The L1{sub 2} phase formation is accompanied by a transient internal friction peak. • Substitution of Ga atoms by Al slows down the massive formation of the L1{sub 2} phase. • TEM study of Fe–Ga–Al alloy proves weak D0{sub 3} ordering and formation L1{sub 2} phase. - Abstract: The structure of binary Fe–27at.%Ga and ternary Fe–18at.%Ga–6at.%Al alloys is studied after different annealing regimes of as quenched samples. This paper focuses mainly on early stages of different phase transitions: from A2 to D0{sub 3}, to L1{sub 2} and D0{sub 19}, which decrease functional properties of Fe–Ga alloys. Formation of stable phases goes through formation of metastable phases: according to XRD, the D0{sub 3} ordering of practically disordered A2 solid solution clearly takes place at 150 °C, while formation of equilibrium fcc ordered L1{sub 2} phase starts after four hours annealing at 350 °C. Upon continuous heating, the transition from D0{sub 3} to L1{sub 2} phase is accompanied by a transient internal friction peak. On its turn, the phase transitions are retarded in the ternary Fe–18Ga–5Al alloy, although a careful TEM study of the ternary alloy proves weak D0{sub 3} ordering in the as-quenched state and formation of small precipitates of L1{sub 2} phase (not detectable by X-ray) after four hours annealing at 275 °C. The presence of carbon in studied alloys leads to appearance of Snoek-type relaxation in both binary and ternary alloys: the peak in binary Fe–27Ga alloy is unimodal with activation energy of about 1 eV, and it has bi-modal shape in the ternary alloy Fe–18Ga–5Al with activation energies of about 1.1 and 1.4 eV, corresponding to carbon atom diffusion under stress in vicinity of Ga and Al atoms, respectively.

  20. Completed Local Ternary Pattern for Rotation Invariant Texture Classification

    Directory of Open Access Journals (Sweden)

    Taha H. Rassem

    2014-01-01

    Full Text Available Despite the fact that the two texture descriptors, the completed modeling of Local Binary Pattern (CLBP and the Completed Local Binary Count (CLBC, have achieved a remarkable accuracy for invariant rotation texture classification, they inherit some Local Binary Pattern (LBP drawbacks. The LBP is sensitive to noise, and different patterns of LBP may be classified into the same class that reduces its discriminating property. Although, the Local Ternary Pattern (LTP is proposed to be more robust to noise than LBP, however, the latter’s weakness may appear with the LTP as well as with LBP. In this paper, a novel completed modeling of the Local Ternary Pattern (LTP operator is proposed to overcome both LBP drawbacks, and an associated completed Local Ternary Pattern (CLTP scheme is developed for rotation invariant texture classification. The experimental results using four different texture databases show that the proposed CLTP achieved an impressive classification accuracy as compared to the CLBP and CLBC descriptors.

  1. On the interpretation, verification and calibration of ternary probabilistic forecasts

    CERN Document Server

    Jupp, Tim E; Coelho, Caio A S; Stephenson, David B

    2011-01-01

    We develop a geometrical interpretation of ternary probabilistic forecasts in which forecasts and observations are regarded as points inside a triangle. Within the triangle, we define a continuous colour palette in which hue and colour saturation are defined with reference to the observed climatology. In contrast to current methods, forecast maps created with this colour scheme convey all of the information present in each ternary forecast. The geometrical interpretation is then extended to verification under quadratic scoring rules (of which the Brier Score and the Ranked Probability Score are well--known examples). Each scoring rule defines an associated triangle in which the square roots of the \\emph{score}, the \\emph{reliability}, the \\emph{uncertainty} and the \\emph{resolution} all have natural interpretations as root--mean--square distances. This leads to our proposal for a \\emph{Ternary Reliability Diagram} in which data relating to verification and calibration can be summarised. We illustrate these id...

  2. [Synthesis and luminescence properties of reactive ternary europium complexes].

    Science.gov (United States)

    Guo, Dong-cai; Shu, Wan-gen; Zhang, Wei; Liu, You-nian; Zhou, Yue

    2004-09-01

    In this paper, five new reactive ternary europium complexes were synthesized with the first ligand of 1,10-phenanthroline and the reactive second ligands of maleic anhydride, acrylonitrile, undecenoic acid, oleic acid and linoleic acid, and also characterized by means of elemental analysis, EDTA titrimetric method, FTIR spectra and UV spectra. The fluorescence spectra show that the five new ternary complexes have much higher luminescence intensity than their corresponding binary complexes, and the synergy ability sequence of the five reactive ligands is as follows: linoleic acid > oleic acid > acrylonitrile > maleic anhydride > undecenoic acid. At the same time, the reactive ternary europium complexes coordinated with the reactive ligands, which can be copolymerized with other monomers, will provide a new way for the synthesis of bonding-type rare earth polymer functional materials with excellent luminescence properties.

  3. Thermodynamic evaluation of hypereutectic Al-Si (A390) alloy with addition of Mg

    Energy Technology Data Exchange (ETDEWEB)

    Hekmat-Ardakan, Alireza [Ecole Polytechnique de Montreal, Dep. de Genie Chimique, P.O. Box 6079, Centre-Ville, Montreal, Quebec, H3C 3A7 (Canada); Ajersch, Frank, E-mail: frank.ajersch@polymtl.ca [Ecole Polytechnique de Montreal, Dep. de Genie Chimique, P.O. Box 6079, Centre-Ville, Montreal, Quebec, H3C 3A7 (Canada)

    2010-05-15

    This paper presents the thermodynamic evaluation of A390 hypereutectic Al-Si alloy (Al-17% Si-4.5% Cu-0.5% Mg) and alloys up to 10% Mg, using the Factsage (registered) software. Two critical compositions were detected at 4.2% and 7.2% Mg where the temperatures of the liquidus, the start of the binary and of the ternary eutectic reaction are changed. These critical compositions show differences in the formation of Mg{sub 2}Si intermetallic particles during the solidification interval. For compositions up to 4.2% Mg, the Mg{sub 2}Si intermetallic phase first appears in the ternary eutectic zone. With Mg contents between 4.2% and 7.2%, Mg{sub 2}Si particle appears in both the binary and ternary eutectic reactions. Above 7.2% Mg, it solidifies as a primary phase and also during the binary and ternary reactions. The calculated liquid fraction vs. temperature curves also showed a decrease of the eutectic formation temperature (knee point temperature) with the addition of Mg content up to 4.2% Mg. This temperature becomes almost constant up to 10% Mg. The calculation of eutectic formation temperature shows a good agreement with differential scanning calorimetry (DSC) tests.

  4. Studies on yttrium-containing smart alloys

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Felix; Wegener, Tobias; Litnovsky, Andrey; Rasinski, Marcin; Linsmeier, Christian [Forschungszentrum Juelich GmbH, Institut fuer Energie- und Klimaforschung - Plasmaphysik (Germany); Mayer, Joachim [Ernst Ruska-Centrum, 52425 Juelich (Germany)

    2016-07-01

    Tungsten is the main candidate as plasma-facing armour material for future fusion reactors, like DEMO. Advantages of tungsten include high melting point, high thermal conductivity, low tritium retention, and low erosion yield. A problem is oxide volatilisation under accidental conditions where the temperature of the first wall can reach 1200 K to 1450 K and air ingress occurs. Therefore smart tungsten alloys are developed. Smart alloys are supposed to preserve properties of tungsten during plasma operation coupled with suppressed tungsten oxide formation in case of an accident. Lab-scale tungsten-chromium-yttrium (W-Cr-Y) samples prepared by magnetron sputtering are used as model system. The mechanisms of oxidation and its dynamics are studied using a thermogravimetric system, focussed ion beam, and electron microscopy. A composition scan was conducted: The new material composition featuring W, ∝ 12 wt.% Cr, ∝ 0.3 wt.% Y showed strongest suppression of oxidation, no pores, and least internal oxidation. At 1273 K in argon-oxygen atmosphere an oxidation rate of 3 . 10{sup -6} mg{sup 2}cm{sup -4}s{sup -1} was measured. At 1473 K ternary W-Cr-Y alloys suppressed evaporation up to 20 min while for W-Cr evaporation was already evident after 5 min. Comparison of passivation in dry and humid atmosphere, at temperatures of 1073 K to 1473 K is performed.

  5. Multimetallic alloy nanotubes with nanoporous framework.

    Science.gov (United States)

    Choi, Bu-Seo; Lee, Young Wook; Kang, Shin Wook; Hong, Jong Wook; Kim, Jung; Park, Inkyu; Han, Sang Woo

    2012-06-26

    One-dimensional nanotubes (NTs) that consist of multiple metallic components are promising platforms for potential applications, whereas only a few synthetic methods of multimetallic NTs have been reported to date. In the present work, we developed a general synthesis route for the production of uniform multicomponent one-dimensional tubular nanostructures with various combinations of Pt, Pd, and Ag by using ZnO nanowires (NWs) as sacrificial templates. The ZnO NWs serve not only as physical templates but also as nucleation sites for the reduction of metal precursors, and thereby several metal precursors could be reduced simultaneously to produce multimetallic NTs. By using this approach, Pt-Pd, Pt-Ag, and Pd-Ag binary alloy NTs, and even Pt-Pd-Ag ternary alloy NTs could be successfully prepared. The prepared Pt-Pd binary alloy NTs exhibited improved electrocatalytic activity and stability toward ethanol oxidation due to their characteristic tubular morphology with well-interconnected nanoporous framework and synergism between two constituent metals. Furthermore, our approach can facilitate the fabrication of patterned multimetallic NT arrays on solid and flexible substrates with strong mechanical robustness. The present templating method does not require any extra steps to remove templates or additional surfactants which are often required to control the shape of nanostructures. This strategy offers a convenient, versatile, low-cost, and highly valuable approach to the fabrication of multimetallic nanostructures with various components and compositions.

  6. The welding metallurgy of HASTELLOY alloys C-4, C-22, and C-276

    Science.gov (United States)

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

    1986-11-01

    The welding metallurgy (solidification and solid state transformations) of HASTELLOY* Alloys C-4, C-22, and C-276 has been determined. Varestraint hot-cracking tests performed on commercial alloys revealed a weldability ranking as follows: C-4 > C-22 > C-276. All alloys would be expected to have good weldability, with Alloy C-4 having a very low hot-cracking tendency, comparable to 304L stainless steel. Microstructures of gas-tungsten-arc welds of these alloys have been characterized by scanning electron microscopy and analytical electron microscopy. Intermetallic secondary solidification constituents have been found associated with weld metal hot cracks in Alloys C-276 and C-22. In Alloy C-276, this constituent is a combination of P and ώ phases, and in Alloy C-22, this constituent is composed of σ, P, and ώ phases. With phase composition data obtained by AEM techniques and available ternary (Ni-Cr-Mo) phase diagrams, an equivalent chemistry model is proposed to account for the microstructures observed in each alloy's weld metal.

  7. Effect of composition on the high rate dynamic behaviour of tungsten heavy alloys

    Directory of Open Access Journals (Sweden)

    Latif Kesemen

    2015-01-01

    Full Text Available Tungsten heavy alloys are currently used as kinetic energy penetrators in military applications due to their high density and superior mechanical properties. In the literature, quasi-static properties of different tungsten heavy alloys based on W-Ni-Cu and W-Ni-Fe ternary systems are well documented and presented. However, comparison of the dynamic behaviour of these alloys in terms of the correlation between quasi-static mechanical characterization and dynamical properties is lacking. In the present study, dynamic properties of tungsten heavy alloys having different binder phase compositions (90W-7Ni-3Cu and 90W-8Ni-2Fe at different projectile velocities were investigated. The examined and tested alloys were produced through the conventional powder metallurgy route of mixing, cold compaction and sintering. Mechanical characterization of these alloys was performed. In the ballistic tests, cylindrical tungsten heavy alloys with L/D ratio of 3 were impacted to hardened steel target at different projectile velocities. After the ballistic tests, deformation characteristics of test specimens during dynamic loading were evaluated by comparing the change of length and diameter of the specimens versus kinetic energy densities. The study concluded that 90W-8Ni-2Fe alloy has better perforation characteristics than 90W-7Ni-3Cu alloy.

  8. Effect of composition on the high rate dynamic behaviour of tungsten heavy alloys

    Science.gov (United States)

    Latif, Kesemen; Kaan, Çalışkan N.; Emrah, Konokman H.; Nuri, Durlu

    2015-09-01

    Tungsten heavy alloys are currently used as kinetic energy penetrators in military applications due to their high density and superior mechanical properties. In the literature, quasi-static properties of different tungsten heavy alloys based on W-Ni-Cu and W-Ni-Fe ternary systems are well documented and presented. However, comparison of the dynamic behaviour of these alloys in terms of the correlation between quasi-static mechanical characterization and dynamical properties is lacking. In the present study, dynamic properties of tungsten heavy alloys having different binder phase compositions (90W-7Ni-3Cu and 90W-8Ni-2Fe) at different projectile velocities were investigated. The examined and tested alloys were produced through the conventional powder metallurgy route of mixing, cold compaction and sintering. Mechanical characterization of these alloys was performed. In the ballistic tests, cylindrical tungsten heavy alloys with L/D ratio of 3 were impacted to hardened steel target at different projectile velocities. After the ballistic tests, deformation characteristics of test specimens during dynamic loading were evaluated by comparing the change of length and diameter of the specimens versus kinetic energy densities. The study concluded that 90W-8Ni-2Fe alloy has better perforation characteristics than 90W-7Ni-3Cu alloy.

  9. Changes in the interface structure and strength of diffusion brazed joints of Al-Si alloy castings

    Energy Technology Data Exchange (ETDEWEB)

    Osawa, T. [Aoyamagakuin Univ., Tokyo (Japan). Coll. of Science and Technology

    1995-06-01

    The diffusion brazing process, which utilizes diffusion between the base metal and the filler metal, has been tried for joining Al-Si alloy castings. If a ternary eutectic Al-Cu-Si alloy system with a lower melting point than the Al-Si system base metal is produced at the braze interface by the diffusion reaction between the base metal and the cooper filler metal, it may be possible to join an Al-Si system alloy casting by the diffusion brazing process, using a ternary eutectic Al-Si-Cu alloy as a filler metal. In this experiment both copper and brass materials were used as preforms. It was clarified that the diffusion brazing process with a copper or brass preform could be used for all hypoeutectic, eutectic and hypereutectic alloys of Al-Si system castings, and that the minimum temperature where the braze interface, showed a liquid phase structure was 530 C for the copper preform and 510 C for the brass preform. The shear strength of the diffusion brazed joint was dependent on the chemical compositions of the base metal, the type of material for the preform, and brazing temperature and time. The maximum strength of the diffusion brazed joint under optimum conditions was 130 to 150 MPa for the base metal of both Al-7Si and Al-12Si alloy castings and 100 to 130 MPa for the base metal of Al-20Si alloy casting.

  10. Evaluation of Contact Friction in Fracture of Rotationally Bent Nitinol Endodontic Files

    Science.gov (United States)

    Haimed, Tariq Abu

    2011-12-01

    The high flexibility of rotary Nitinol (Ni-Ti) files has helped clinicians perform root canal treatments with fewer technical errors than seen with stainless steel files. However, intracanal file fracture can occur, compromising the outcome of the treatment. Ni-Ti file fracture incidence is roughly around 4% amongst specialists and higher amongst general practitioners. Therefore, eliminating or reducing this problem should improve patient care. The aim of this project was to isolate and examine the role of friction between files and the canal walls of the glass tube model, and bending-related maximum strain amplitudes, on Ni-Ti file lifetimes-tofracture in the presence of different irrigant solutions and file coatings. A specifically designed device was used to test over 300 electropolished EndoSequenceRTM Ni-Ti files for number of cycles to failure (NCF) in smooth, bent glass tube models at 45 and 60 degrees during dry, coated and liquid-lubricated rotation at 600rpm. Fractured files were examined under Scanning Electron Microscopy (SEM) afterwards. Four different file sizes 25.04, 25.06, 35.04, 35.06 (diameter in mm/taper %) and six surface modification conditions were used independently. These conditions included, three solutions; (1) a surfactant-based solution, Surface-Active-Displacement-Solution (SADS), (2) a mouth wash proven to remove biofilms, Delmopinol 1%(DEL), and (3) Bleach 6% (vol.%), the most common antibacterial endodontic irrigant solution. The conditions also included two low-friction silane-based coating groups, 3-Hepta-fluoroisopropyl-propoxymethyl-dichlorosilane (3-HEPT) and Octadecyltrichlorosilane (ODS), in addition to an as-received file control group (Dry). The coefficient of friction (CF) between the file and the canal walls for each condition was measured as well as the surface tension of the irrigant solutions and the critical surface tension of the coated and uncoated files by contact angle measurements. The radius of curvature and

  11. Ternary jitter-based true random number generator

    Science.gov (United States)

    Latypov, Rustam; Stolov, Evgeni

    2017-01-01

    In this paper a novel family of generators producing true uniform random numbers in ternary logic is presented. The generator consists of a number of identical ternary logic combinational units connected into a ring. All the units are provided to have a random delay time, and this time is supposed to be distributed in accordance with an exponential distribution. All delays are supposed to be independent events. The theory of the generator is based on Erlang equations. The generator can be used for test production in various systems. Features of multidimensional random vectors, produced by the generator, are discussed.

  12. Liquid-liquid equilibria for ternary polymer mixtures

    Science.gov (United States)

    Oh, Suk Yung; Bae, Young Chan

    2011-01-01

    A molecular thermodynamic model for multicomponent systems based on a closed-packed lattice model is presented based on two contributions; entropy and energy contribution. The calculated liquid-liquid equilibria of ternary chainlike mixtures agreed with Monte Carlo simulation results. The proposed model can satisfactorily predict Types 0, 1, 2 and 3 phase separations of the Treybal classification. The model parameters obtained from the binary systems were used to directly predict real ternary systems and the calculated results correlated well with experimental data using few adjustable parameters. Specific interactions in associated binary systems were considered using a secondary lattice.

  13. PM1 steganographic algorithm using ternary Hamming Code

    Directory of Open Access Journals (Sweden)

    Kamil Kaczyński

    2015-12-01

    Full Text Available PM1 algorithm is a modification of well-known LSB steganographic algorithm. It has increased resistance to selected steganalytic attacks and increased embedding efficiency. Due to its uniqueness, PM1 algorithm allows us to use of larger alphabet of symbols, making it possible to further increase steganographic capacity. In this paper, we present the modified PM1 algorithm which utilizies so-called syndrome coding and ternary Hamming code. The modified algorithm has increased embedding efficiency, which means fewer changes introduced to carrier and increased capacity.[b]Keywords[/b]: steganography, linear codes, PM1, LSB, ternary Hamming code

  14. First principles investigation of the activity of thin film Pt, Pd and Au surface alloys for oxygen reduction

    DEFF Research Database (Denmark)

    Tripkovic, Vladimir; Hansen, Heine Anton; Rossmeisl, Jan

    2015-01-01

    Further advances in fuel cell technologies are hampered by kinetic limitations associated with the sluggish cathodic oxygen reduction reaction. We have investigated a range of different formulations of binary and ternary Pt, Pd and Au thin films as electrocatalysts for oxygen reduction. The most...... driving force for surface segregation, diffusion to defects or surface self-assembling. On the basis of stability and activity analysis we conclude that the near surface alloy of Pd in Pt and some PdAu binary and PtPdAu ternary thin films with a controlled amount of Au are the best catalysts for oxygen...

  15. The ternary system: silicon-uranium-vanadium

    Energy Technology Data Exchange (ETDEWEB)

    Noel, Henri [Laboratoire de Chimie du Solide et Materiaux, UMR-CNRS 6226, Universite de Rennes I, Avenue du General Leclerc, F-35042 Rennes, Cedex (France); Rogl, Peter Franz, E-mail: peter.franz.rogl@univie.ac.a [Institute of Physical Chemistry, University of Vienna, A-1090 Wien, Waehringerstrasse 42 (Austria)

    2010-09-01

    Phase equilibria in the system Si-U-V were established at 1100 {sup o}C by optical microscopy, EMPA and X-ray diffraction. Two ternary compounds were observed, U{sub 2}V{sub 3}Si{sub 4} and (U{sub 1-x}V{sub x}){sub 5}Si{sub 3}, for which the crystal structures were elucidated by X-ray powder data refinement and found to be isotypic with the monoclinic U{sub 2}Mo{sub 3}Si{sub 4}-type (space group P2{sub 1}/c; a = 0.6821(3), b = 0.6820(4), c = 0.6735(3) nm, {beta} = 109.77(1){sup o}) and the tetragonal W{sub 5}Si{sub 3}-type (space group I4/mcm, a = 1.06825(2), c = 0.52764(2) nm), respectively. (U{sub 1-x}V{sub x}){sub 5}Si{sub 3} appears at 1100 {sup o}C without any significant homogeneity region at x {approx} 0.2 resulting in a formula U{sub 4}VSi{sub 3} which corresponds to a fully ordered atom arrangement. DTA experiments clearly show decomposition of this phase above 1206 {sup o}C revealing a two-phase region U{sub 3}Si{sub 2} + V{sub 3}Si. At 1100 {sup o}C U{sub 4}VSi{sub 3} is in equilibrium with V{sub 3}Si, V{sub 5}Si{sub 3}, U{sub 3}Si{sub 2} and U(V). At 800 {sup o}C U{sub 4}VSi{sub 3} forms one vertex of the tie-triangle to U{sub 3}Si and V{sub 3}Si. Due to the rather high thermodynamic stability of V{sub 3}Si and the corresponding tie-lines V{sub 3}Si + liquid at 1100 {sup o}C and V{sub 3}Si + U(V) below 925 {sup o}C, no compatibility exists between U{sub 3}Si or U{sub 3}Si{sub 2} and vanadium metal.

  16. Microstructure, Mechanical Property, and Phase Transformation of Quaternary NiTiFeNb and NiTiFeTa Shape Memory Alloys

    National Research Council Canada - National Science Library

    Yulong Liang; Shuyong Jiang; Yanqiu Zhang; Junbo Yu

    2017-01-01

    Based on ternary Ni45Ti51.8Fe3.2 (at %) shape memory alloy (SMA), Nb and Ta elements are added to an NiTiFe SMA by replacing Ni element, and consequently quaternary Ni44Ti51.8Fe3.2Nb1 and Ni44Ti51.8Fe3.2Ta1...

  17. The atomic structure of ternary amorphous TixSi1-xO2 hybrid oxides.

    Science.gov (United States)

    Landmann, M; Köhler, T; Rauls, E; Frauenheim, T; Schmidt, W G

    2014-06-25

    Atomic length-scale order characteristics of binary and ternary amorphous oxides are presented within the framework of ab initio theory. A combined numerically efficient density functional based tight-binding molecular dynamics and density functional theory approach is applied to model the amorphous (a) phases of SiO2 and TiO2 as well as the amorphous phase of atomically mixed TixSi1-xO2 hybrid-oxide alloys over the entire composition range. Short and mid-range order in the disordered material phases are characterized by bond length and bond-angle statistics, pair distribution function analysis, coordination number and coordination polyhedra statistics, as well as ring statistics. The present study provides fundamental insights into the order characteristics of the amorphous hybrid-oxide frameworks formed by versatile types of TiOn and SiOm coordination polyhedra. In a-SiO2 the fourfold crystal coordination of Si ions is almost completely preserved and the atomic structure is widely dominated by ring-like mid-range order characteristics. In contrast, the structural disorder of a-TiO2 arises from short-range disorder in the local coordination environment of the Ti ion. The coordination number analysis indicates a large amount of over and under-coordinated Ti ions (coordination defects) in a-TiO2. Aside from the ubiquitous distortions of the crystal-like coordinated polyhedra, even the basic coordination-polyhedra geometry type changes for a significant fraction of TiO6 units (geometry defects). The combined effects of topological and chemical disorder in a-TixSi1-xO2 alloys lead to a continuos increase in both the Si as well as the Ti coordination number with the chemical composition x. The important roles of intermediate fivefold coordination states of Ti and Si cations are highlighted for ternary a-TixSi1-xO2 as well as for binary a-TiO2. The continuous decrease in ring size with increasing Ti content reflects the progressive loss of mid-range order structure

  18. Preparation of Binary and Ternary Oxides by Molten Salt Method and its Electrochemical Properties

    Science.gov (United States)

    Reddy, M. V.; Theng, L. Pei; Soh, Hulbert; Beichen, Z.; Jiahuan, F.; Yu, C.; Ling, A. Yen; Andreea, L. Y.; Ng, C. H. Justin; Liang, T. J. L. Galen; Ian, M. F.; An, H. V. T.; Ramanathan, K.; Kevin, C. W. J.; Daryl, T. Y. W.; Hao, T. Yi; Loh, K. P.; Chowdari, B. V. R.

    2013-07-01

    We report simple binary oxides namely SnO2, TiO2, CuO, MnO2, Fe2O3, Co3O4 and ternary oxides like MnCo2O4 by molten salt method at a temperature range of 280°C to 950°C in air and discuss the effect of morphology, crystal structure and electrochemical properties of binary and ternary oxides. Materials were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Brunauer-Emmett-Teller (BET) surface area methods. XRD patterns showed all MSM prepared materials exhibited characteristic lattice parameter values. BET surface area varies depending on the nature of the material, molten salt and preparation temperature and the obtained values are in the range, 1 to 160 m2/g. Electrochemical properties were studied using cyclic voltammetry (CV) and electrochemical performance studies were carried in the voltage range, 0.005-1.0V for SnO2, 1.0-2.8V for TiO2 and Fe2O3, MCo2O4 (M = Co, Mn), MnO2 and CuO were cycled in the range, 0.005-3.0V. At a current rates of 30-100 mA/g and a scan rate of 0.058 mV/sec was used for galvanostatic cycling and cyclic voltammetry. SnO2 showed that an alloying-de-alloying reaction occurs at ˜0.2 and ˜0.5 V vs. Li. TiO2 main intercalation and de-interaction reactions at ˜1.7 and ˜1.8 V vs. Li. Co3O4, MnCo2O4, and MnO2 main discharge potentials at ˜1.2, 0.9V and 0.4V, resp. and charge potentials peak ˜2.0V and 1.5V vs. Li. CuO prepared at 750°C exhibited main anodic peak at ˜2.45V and cathodic peaks at ˜0.85V and ˜1.25V. We discussed the possible reaction mechanisms and Li-storage performance values in detail.

  19. Electrical resistivity of NaPb compound-forming liquid alloy using ab ...

    Indian Academy of Sciences (India)

    Complex formation model [17,18] has its basis on the fact that a typical binary liquid alloy forms a compound at one or more stoichiometric compositions and therefore behaves like a ternary mixture consisting of free atoms A, B and a chemical compound or pseudomolecule AαBβ such that αA + βB = AαBβ. There are nA.

  20. Retrospective analysis of the results of implanting Nitinol pistons with heat-crimping piston loops in stapes surgery.

    Science.gov (United States)

    Hornung, Joachim Albert; Brase, Christoph; Bozzato, Alessandro; Zenk, Johannes; Schick, Bernhard; Iro, Heinrich

    2010-01-01

    The study presented here evaluates the hearing results after the implantation of a new nickel-titanium (Nitinol) prosthesis in stapes surgery; on heating, this prosthesis crimps itself around the long process of the incus. In addition, we compare the outcome with results published in the literature. The medical records of all patients who underwent surgery for otosclerosis with implantation of a Nitinol piston during the period 2004-2006 were evaluated retrospectively. 83 patients (58 women and 25 men), with a provisional diagnosis of otosclerosis that was confirmed during surgery in all but one of the cases, were treated by primary stapes surgery (85 ears). We were able to include 53 patients (55 ears) who had audiograms with air and bone conduction preoperatively and both 2-6 weeks and about 1 year after surgery. We found a mean air-bone gap (ABG) for the frequencies 0.5, 1, 2 and 4 kHz (ABG4000) of 10.4 ± 5.5 dB after a mean postoperative follow-up period of 24.5 ± 16 days, and of 7.4 ± 3.7 dB after 462 ± 119 days. For the frequencies 0.5, 1, 2 and 3 kHz (ABG3000), the results were 9.1 ± 4.8 and 6.4 ± 3.9 dB. The differences in preoperative versus postoperative air-bone gap, referred to as ABGC, after 25 and 462 days, respectively, were 19.4 ± 8.9 and 22.3 ± 8.8 dB for AGB4000, and 19.5 ± 8.8 and 22.2 ± 8.9 for ABG3000. Very good results were achieved with a new nickel-titanium prosthesis that crimps itself around the long process of the incus, thus facilitating stapes surgery and at the same time stabilizing the high quality of the results. However, no long-term results after 10 years or more, which would allow a final judgment, are yet available.

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

    Science.gov (United States)

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

    1977-01-01

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

  2. Researches Regarding the Effect of Nitinol Vibration Damper Applied to Infrastructures

    Directory of Open Access Journals (Sweden)

    Daniel Amariei

    2009-10-01

    Full Text Available Many of the performed researches all around the world aim to develop advanced technologies in order to enhance the performances of the infrastructure systems, different from the actual ones, fact which involves multidisciplinary research (IT, sensoring, electronics, smart materials and others, aiming to assist engineers in realizing full benefits of structural health monitoring. The paper presents a preliminary feasibility study of a system that can be used for damping of structural vibrations. Thus, shape memory alloys (SMA components can affect through two mechanisms the structure’s vibrations. The stresses from a SMA element that realize phase transformations, as a result of vibrations, have an effect on the frequency-amplitude characteristics. In addition, a dissipation of energy due to hysteresis in a SMA element can reduce the natural frequency and affect forced vibrations.

  3. Design and Control of a Proof-of-Concept Active Jet Engine Intake Using Shape Memory Alloy Actuators

    Science.gov (United States)

    Song, Gangbing; Ma, Ning; Penney, Nicholas; Barr, Todd; Lee, Ho-Jun; Arnold, Steven M.

    2004-01-01

    The design and control of a novel proof-of-concept active jet engine intake using Nickel-Titanium (Ni-Ti or Nitinol) shape memory alloy (SMA) wire actuators is used to demonstrate the potential of an adaptive intake to improve the fuel efficiency of a jet engine. The Nitinol SMA material is selected for this research due to the material's ability to generate large strains of up to 5 percent for repeated operations, a high power-to-weight ratio, electrical resistive actuation, and easy fabrication into a variety of shapes. The proof-of-concept engine intake employs an overlapping leaf design arranged in a concentric configuration. Each leaf is mounted on a supporting bar that rotates upon actuation by SMA wires electrical resistive heating. Feedback control is enabled through the use of a laser range sensor to detect the movement of a leaf and determine the radius of the intake area. Due to the hysteresis behavior inherent in SMAs, a nonlinear robust controller is used to direct the SMA wire actuation. The controller design utilizes the sliding-mode approach to compensate for the nonlinearities associated with the SMA actuator. Feedback control experiments conducted on a fabricated proof-of-concept model have demonstrated the capability to precisely control the intake area and achieve up to a 25 percent reduction in intake area. The experiments demonstrate the feasibility of engine intake area control using the proposed design.

  4. Evaluation of Nitinol staples for the Lapidus arthrodesis in a reproducible biomechanical model

    Directory of Open Access Journals (Sweden)

    Nicholas Alexander Russell

    2015-12-01

    Full Text Available While the Lapidus procedure is a widely accepted technique for treatment of hallux valgus, the optimal fixation method to maintain joint stability remains controversial. The purpose of this study was to evaluate the biomechanical properties of new Shape Memory Alloy staples arranged in different configurations in a repeatable 1st Tarsometatarsal arthrodesis model. Ten sawbones models of the whole foot (n=5 per group were reconstructed using a single dorsal staple or two staples in a delta configuration. Each construct was mechanically tested in dorsal four-point bending, medial four-point bending, dorsal three-point bending and plantar cantilever bending with the staples activated at 37°C. The peak load, stiffness and plantar gapping were determined for each test. Pressure sensors were used to measure the contact force and area of the joint footprint in each group. There was a significant (p < 0.05 increase in peak load in the two staple constructs compared to the single staple constructs for all testing modalities. Stiffness also increased significantly in all tests except dorsal four-point bending. Pressure sensor readings showed a significantly higher contact force at time zero and contact area following loading in the two staple constructs (p < 0.05. Both groups completely recovered any plantar gapping following unloading and restored their initial contact footprint. The biomechanical integrity and repeatability of the models was demonstrated with no construct failures due to hardware or model breakdown. Shape memory alloy staples provide fixation with the ability to dynamically apply and maintain compression across a simulated arthrodesis following a range of loading conditions.

  5. Measurements for Cu and Si diffusivities in Al-Cu-Si alloys by diffusion couples

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Dingfei [College of Materials Science and Engineering, Chongqing University, Chongqing 400045 (China)]. E-mail: zhangdingfei@cqu.edu.cn; Morral, John E. [Department of Materials Science and Engineering, Ohio State University, OH 43210 (United States); Brody, Harold D. [Institute of Materials Science, University of Connecticut, CT 06268 (United States)

    2007-02-25

    This paper deals with diffusivity measurements for Cu and Si atoms in Al-Cu-Si alloys by diffusion couples. With Cu and Si concentration profiles in the diffusion couples treated by different heating temperatures and times, their diffusivities including D {sub CuCu}, D {sub SiSi}, D {sub CuSi} and D {sub SiCu} in Al-Cu-Si ternary alloys could be calculated and their D {sub 0} and Q also could be obtained by their diffusivities under different temperatures.

  6. Equilibrium compositional distribution in freestanding ternary semiconductor quantum dots: the case of In(x)Ga(1-x)As.

    Science.gov (United States)

    Pandey, Sumeet C; Maroudas, Dimitrios

    2011-12-21

    We report the findings of a systematic computational study that addresses the effects of surface segregation on the atomic distribution at equilibrium of constituent group-III atoms in freestanding ternary semiconductor In(x)Ga(1-x)As nanocrystals. Our analysis is based on density functional theory calculations in conjunction with Monte Carlo simulations of the freestanding nanocrystals using a DFT-re-parameterized valence force field description of interatomic interactions. We have determined the equilibrium concentration profiles as a function of nanocrystal size (d), composition (x), and temperature (T). The ranges of d, x, and T are explored and demonstrate surface segregation and phase separation that leads to different extents of alloying in the nanocrystal core and in the near-surface regions. We find that formation of core/shell-like quantum dots characterized by an In-deficient core and an In-rich shell with a diffuse interface is favored at equilibrium. The analysis elucidates the relationship between the constituent species distribution in the nanocrystal and the parameters that can be tuned experimentally to design synthesis routes for tailoring the properties of ternary quantum dots.

  7. Equilibrium Compositional Distribution in Freestanding Ternary Semiconductor Quantum Dots: The Case of In(x)Ga(1-x)As

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Sumeet C.; Maroudas, Dimitrios

    2011-01-01

    We report the findings of a systematic computational study that addresses the effects of surface segregation on the atomic distribution at equilibrium of constituent group-III atoms in freestanding ternary semiconductor InxGa1-xAs nanocrystals. Our analysis is based on density functional theory calculations in conjunction with Monte Carlo simulations of the freestanding nanocrystals using a DFT-re-parameterized valence force field description of interatomic interactions. We have determined the equilibrium concentration profiles as a function of nanocrystal size (d), composition (x), and temperature (T). The ranges of d, x, and T are explored and demonstrate surface segregation and phase separation that leads to different extents of alloying in the nanocrystal core and in the near-surface regions. We find that formation of core/shell-like quantum dots characterized by an In-deficient core and an In-rich shell with a diffuse interface is favored at equilibrium. The analysis elucidates the relationship between the constituent species distribution in the nanocrystal and the parameters that can be tuned experimentally to design synthesis routes for tailoring the properties of ternary quantum dots.

  8. Co(x)Ni(4-x)Sb(12-y)Sn(y) Ternary Skutterudites: Processing and Thermoelectric Properties

    Science.gov (United States)

    Mackey, Jon; Sehirlioglu, Alp; Dynys, Fred

    2014-01-01

    Skutterudites have proven to be a useful thermoelectric system as a result of their high figure of merit, favorable mechanical properties, and good thermal stability. Binary skutterudites have received the majority of interest in recent years, as a result of successful double and triple filling schemes. Ternary skutterudites, such as Ni4Sb7Sn5, also demonstrate good thermoelectric performance, with high power factor and low thermal conductivity. Ternary skutterudites, as contrasted to binary systems, provide more possibility for tuning electronic structure as substitutions can be studied on three elements. The Co(x)Ni(4-x)Sb(12-y)Sn(y) system has been investigated as both a p- and n-type thermoelectric material, stable up to 200 C. The system is processed through a combination of solidification, mechanical alloying, and hot pressing steps. Rietveld structure refinement has revealed an interesting occupancy of Sn on both the 24g Wyckoff position with Sb as well as the 2a position as a rattler. In addition to thermoelectric properties, detailed processing routes have been investigated on the system.

  9. The precipitation process in Mg-Ca-(Zn) alloys investigated by positron annihilation spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, Yanicet [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain); Departamento de Fisica de Materiales, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, 28040 Madrid (Spain)], E-mail: yanicet@fis.ucm.es; Monge, Miguel Angel; Pareja, Ramiro [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain)

    2008-09-08

    Coincidence doppler broadening (CDB) spectroscopy has been applied to study the precipitation process induced by aging in Mg-1.0 wt.% Ca and Mg-1.0 wt.% Ca-1.0 wt.% Zn alloys. In addition positron lifetime experiments and microhardness measurements have been performed. A peak centered at {approx}11.5 x 10{sup -3}m{sub 0}c is found in the CDB ratio spectra of the alloys aged at 473 K. It is attributed to annihilations with the core electrons of Ca. The results indicate the formation of a particle dispersion that hardens the alloys. This dispersion is correlated with the appearance of the peak attributed to Ca atoms. Zn atoms in the Mg matrix inhibit the formation of quenched-in vacancies bound to Ca atoms in the aged ternary alloy producing the dispersion refinement.

  10. Oxidation of zirconium alloys in 2.5 kPa water vapor for tritium readiness.

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Bernice E.

    2007-11-01

    A more reactive liner material is needed for use as liner and cruciform material in tritium producing burnable absorber rods (TPBAR) in commercial light water nuclear reactors (CLWR). The function of these components is to convert any water that is released from the Li-6 enriched lithium aluminate breeder material to oxide and hydrogen that can be gettered, thus minimizing the permeation of tritium into the reactor coolant. Fourteen zirconium alloys were exposed to 2.5 kPa water vapor in a helium stream at 300 C over a period of up to 35 days. Experimental alloys with aluminum, yttrium, vanadium, titanium, and scandium, some of which also included ternaries with nickel, were included along with a high nitrogen impurity alloy and the commercial alloy Zircaloy-2. They displayed a reactivity range of almost 500, with Zircaloy-2 being the least reactive.

  11. Structure, electronic and mechanical properties of Ga1-xBxP alloys

    Science.gov (United States)

    Zhao, Bin; Zhang, Junqin; Ma, Huihui; Wei, Qun; Yang, Yintang

    2017-09-01

    The structural, electronic and mechanical properties of Ga1-xBxP ternary alloys are carried out by the first-principles based on density functional theory. We studied the effect of composition on the ground state properties such as lattice parameter, band gap and elastic modulus and anisotropy. The elastic anisotropy of Ga1-xBxP alloys have been described through different anisotropic factors. We analyzed elastic anisotropy by depicting the three-dimensional surface structure of elastic modulus. Due to the introduction of boron atoms, the Ga1-xBxP alloys become direct-gap semiconductors at x = 0.25, 0.50 and 0.75. At last, we calculated the average acoustic velocity in different directions and the Debye temperatures for the Ga1-xBxP alloys.

  12. Studies on Molecular Interaction in Ternary Liquid Mixtures

    Directory of Open Access Journals (Sweden)

    R. Uvarani

    2010-01-01

    Full Text Available Ultrasonic velocity, density and viscosity for the ternary liquid mixtures of cyclohexanone with 1-propanol and 1-butanol in carbon tetrachloride were measured at 303 K. The acoustical parameters and their excess values were calculated. The trends in the variation of these excess parameters were used to discuss the nature and strength of the interactions present between the component molecules.

  13. Hierarchic structure formation in binary and ternary polymer blends

    NARCIS (Netherlands)

    Sprenger, M; Walheim, S; Budkowski, A; Steiner, U

    The phase morphology of multi-component polymer blends is governed by the interfacial interactions of its components. We discuss here the domain morphology in thin films of model binary and ternary polymer blends containing polystyrene, poly(methyl metacrylate), and poly(2-vinylpyridine) (PS, PMMA,

  14. Mechanical, microstructure and electrical properties of ternary ZnO ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 38; Issue 3. Mechanical, microstructure and electrical properties of ternary ZnO–V2O5–Mn3O4 varistor with sintering temperature. S El-Rabai A H Khafagy M T Dawoud M T Attia. Volume 38 Issue 3 June 2015 pp 773-781 ...

  15. Intermolecular Interactions in Ternary Glycerol–Sample–H2O

    DEFF Research Database (Denmark)

    Westh, Peter; Rasmussen, Erik Lumby; Koga, Yoshikata

    2011-01-01

    We studied the intermolecular interactions in ternary glycerol (Gly)–sample (S)–H2O systems at 25 °C. By measuring the excess partial molar enthalpy of Gly, HGlyEHEGly, we evaluated the Gly–Gly enthalpic interaction, HGly-GlyEHEGly--Gly, in the presence of various samples (S). For S, tert...

  16. Excess isentropic compressibility and speed of sound of the ternary ...

    Indian Academy of Sciences (India)

    These excess properties of the binary mixtures were fitted to Redlich-Kister equation, while the Cibulka's equation was used to fit the values related to the values to the ternary system. These excess properties have been used to discuss the presence of significant interactions between the component molecules in the binary ...

  17. Robust self-triggered coordination with ternary controllers

    NARCIS (Netherlands)

    De Persis, Claudio; Frasca, Paolo

    2013-01-01

    This paper regards the coordination of networked systems, studied in the framework of hybrid dynamical systems. We design a coordination scheme which combines the use of ternary controllers with a self-triggered communication policy. The communication policy requires the agents to measure, at each

  18. Univolatility curves in ternary mixtures: geometry and numerical computation

    DEFF Research Database (Denmark)

    Shcherbakova, Nataliya; Rodriguez-Donis, Ivonne; Abildskov, Jens

    2017-01-01

    We propose a new non-iterative numerical algorithm allowing computation of all univolatility curves in homogeneous ternary mixtures independently of the presence of the azeotropes. The key point is the concept of generalized univolatility curves in the 3D state space, which allows the main...... computational part to be reduced to a simple integration of a system of ordinary differential equations....

  19. Evaluation of griseofulvin binary and ternary solid dispersions with HPMCAS.

    Science.gov (United States)

    Al-Obaidi, Hisham; Buckton, Graham

    2009-01-01

    The stability and dissolution properties of griseofulvin binary and ternary solid dispersions were evaluated. Solid dispersions of griseofulvin and hydroxypropyl methylcellulose acetate succinate (HPMCAS) were prepared using the spray drying method. A third polymer, poly[N-(2-hydroxypropyl)methacrylate] (PHPMA), was incorporated to investigate its effect on the interaction of griseofulvin with HPMCAS. In this case, HPMCAS can form H bonds with griseofulvin directly; the addition of PHPMA to the solid dispersion may enhance the stability of the amorphous griseofulvin due to greater interaction with griseofulvin. The X-ray powder diffraction results showed that griseofulvin (binary and ternary solid dispersions) remained amorphous for more than 19 months stored at 85% RH compared with the spray-dried griseofulvin which crystallized totally within 24 h at ambient conditions. The Fourier transform infrared scan showed that griseofulvin carbonyl group formed hydrogen bonds with the hydroxyl group in the HPMCAS, which could explain the extended stability of the drug. Further broadening in the peak could be seen when PHPMA was added to the solid dispersion, which indicates stronger interaction. The glass transition temperatures increased in the ternary solid dispersions regardless of HPMCAS grade. The dissolution rate of the drug in the solid dispersion (both binary and ternary) has significantly increased when compared with the dissolution profile of the spray-dried griseofulvin. These results reveal significant stability of the amorphous form due to the hydrogen bond formation with the polymer. The addition of the third polymer improved the stability but had a minor impact on dissolution.

  20. Excess isentropic compressibility and speed of sound of the ternary ...

    Indian Academy of Sciences (India)

    relation (NR), Van Deal's ideal mixing relation (IMR) and Junjie's relation (JR). The results are used to ... The compounds used were 2-propanol (>99 mass%), diethyl ether (>99.5 mass%) and n-hexane (>99 .... The excess speed of sound, uE, is estimated in binary and ternary mixtures using the following expression:.

  1. Viscometric and thermodynamic studies of interactions in ternary ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 117; Issue 3. Viscometric and thermodynamic studies of interactions in ternary solutions containing sucrose and aqueous alkali metal halides at 293.15, 303.15 and 313.15 K. Reena Gupta Mukhtar Singh. Volume 117 Issue 3 May 2005 pp 275-282 ...

  2. Modeling adsorption of binary and ternary mixtures on microporous media

    DEFF Research Database (Denmark)

    Monsalvo, Matias Alfonso; Shapiro, Alexander

    2007-01-01

    The goal of this work is to analyze the adsorption of binary and ternary mixtures on the basis of the multicomponent potential theory of adsorption (MPTA). In the MPTA, the adsorbate is considered as a segregated mixture in the external potential field emitted by the solid adsorbent. This makes i...

  3. A Simple Refraction Experiment for Probing Diffusion in Ternary Mixtures

    Science.gov (United States)

    Coutinho, Cecil A.; Mankidy, Bijith D.; Gupta, Vinay K.

    2010-01-01

    Diffusion is a fundamental phenomenon that is vital in many chemical processes such as mass transport in living cells, corrosion, and separations. We describe a simple undergraduate-level experiment based on Weiner's Method to probe diffusion in a ternary aqueous mixture of small molecular-weight molecules. As an illustration, the experiment…

  4. Electron paramagnetic resonance study of ternary Cu compounds ...

    Indian Academy of Sciences (India)

    Abstract. We report here electron paramagnetic resonance (EPR) measurements at 9 and 34 GHz, and room temperature (T ), in powder and single crystal samples of the ternary compounds of copper nitrate or copper chloride with glycine and 1,10-phenanthroline [Cu(Gly)(phen)(H2O)]·NO3·1.5H2O (1) and.

  5. IMPROVING THE PROPERTIES OF MILD STEEL BY TERNARY ...

    African Journals Online (AJOL)

    Protective coatings are perhaps the most extensively used system for chemical and mechanical degradation in application. ... mechanical and electrochemical resistance bond needful during application. .... binary phase of SiC and ZrO2 results to a reduction in the hardness value compare to the ternary phase which is in ...

  6. Experimental examination of ternary fission in nuclear track emulsion

    Science.gov (United States)

    Mamatkulov, K. Z.; Ambrožová, I.; Artemenkov, D. A.; Bradnova, V.; Firu, E.; Haiduc, M.; Kakona, M.; Kattabekov, R. R.; Marey, A.; Neagu, A.; Ploc, O.; Rusakova, V. V.; Stanoeva, R.; Turek, K.; Zaitsev, A. A.; Zarubin, P. I.; Zarubina, I. G.

    2017-11-01

    Activities performed in preparation for the search for ternary fission of heavy nuclei and the analysis of fragment angular correlations with nuclear track emulsion and an automated microscope are detailed. Surface irradiation of nuclear emulsion by a Cf source was initiated. Planar events containing nothing but fragment triples were found and studied.

  7. Multiscale Modeling of Grain Boundary Segregation and Embrittlement in Tungsten for Mechanistic Design of Alloys for Coal Fired Plants

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Jian; Tomar, Vikas; Zhou, Naixie; Lee, Hongsuk

    2013-06-30

    Based on a recent discovery of premelting-like grain boundary segregation in refractory metals occurring at high temperatures and/or high alloying levels, this project investigated grain boundary segregation and embrittlement in tungsten (W) based alloys. Specifically, new interfacial thermodynamic models have been developed and quantified to predict high-temperature grain boundary segregation in the W-Ni binary alloy and W-Ni-Fe, W-Ni-Ti, W-Ni-Co, W-Ni-Cr, W-Ni-Zr and W-Ni-Nb ternary alloys. The thermodynamic modeling results have been experimentally validated for selected systems. Furthermore, multiscale modeling has been conducted at continuum, atomistic and quantum-mechanical levels to link grain boundary segregation with embrittlement. In summary, this 3-year project has successfully developed a theoretical framework in combination with a multiscale modeling strategy for predicting grain boundary segregation and embrittlement in W based alloys.

  8. An experimental canine patent ductus arteriosus occlusion device based on shape memory polymer foam in a nitinol cage.

    Science.gov (United States)

    Wierzbicki, Mark A; Raines, Sarah B; Gordon, Sonya G; Criscione, John C; Saunders, Ashley B; Birch, Scott; Due, Bradley; Keller, Brandis; Nash, Landon D; Miller, Matthew W; Maitland, Duncan J

    2017-11-01

    Patent ductus arteriosus (PDA) is a congenital cardiovascular defect in which a fetal connection between the aorta and pulmonary artery does not spontaneously close shortly after birth. If left uncorrected serious complications and even death can occur. Surgical ligation is the traditional treatment method; however, it is an invasive procedure, that motivates development of a minimally invasive option. Shape memory polymer (SMP) foams are unique materials that hold promise in the field of minimally invasive occlusion devices. In this work, a prototype nitinol foam cage (NFC) incorporating SMP foams has been designed and evaluated in multiple mechanical and in vitro verification tests. The NFC demonstrated acceptable fatigue resistance in a preliminary strut integrity test, withstanding one million cycles without complete strut fracture. Radial force analysis of both thick- and thin-walled prototype variations generated less vessel distension and wall tension in a vessel mimic compared to a commercial device. The NFCs exhibited negligible in vitro migration, comparable to that of a commercial device, using simplified, ideal models of PDA. Deployment characteristics of the prototypes were evaluated and compared to that of a commercial device when delivered into physiological models of PDA. During mock deployments, a veterinary cardiologist noted that, while deliverable, the thin-walled NFC prototype exhibited poor deployment characteristics, however the thick-walled NFC had deployment characteristics comparable to that of a commercial device. The promising results of this study warrant further investigation of the NFC device for canine PDA closure. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Induction of osteogenic differentiation of adipose derived stem cells by microstructured nitinol actuator-mediated mechanical stress.

    Directory of Open Access Journals (Sweden)

    Sarah Strauß

    Full Text Available The development of large tissue engineered bone remains a challenge in vitro, therefore the use of hybrid-implants might offer a bridge between tissue engineering and dense metal or ceramic implants. Especially the combination of the pseudoelastic implant material Nitinol (NiTi with adipose derived stem cells (ASCs opens new opportunities, as ASCs are able to differentiate osteogenically and therefore enhance osseointegration of implants. Due to limited knowledge about the effects of NiTi-structures manufactured by selective laser melting (SLM on ASCs the study started with an evaluation of cytocompatibility followed by the investigation of the use of SLM-generated 3-dimensional NiTi-structures preseeded with ASCs as osteoimplant model. In this study we could demonstrate for the first time that osteogenic differentiation of ASCs can be induced by implant-mediated mechanical stimulation without support of osteogenic cell culture media. By use of an innovative implant design and synthesis via SLM-technique we achieved high rates of vital cells, proper osteogenic differentiation and mechanically loadable NiTi-scaffolds could be achieved.

  10. Induction of osteogenic differentiation of adipose derived stem cells by microstructured nitinol actuator-mediated mechanical stress.

    Science.gov (United States)

    Strauß, Sarah; Dudziak, Sonja; Hagemann, Ronny; Barcikowski, Stephan; Fliess, Malte; Israelowitz, Meir; Kracht, Dietmar; Kuhbier, Jörn W; Radtke, Christine; Reimers, Kerstin; Vogt, Peter M

    2012-01-01

    The development of large tissue engineered bone remains a challenge in vitro, therefore the use of hybrid-implants might offer a bridge between tissue engineering and dense metal or ceramic implants. Especially the combination of the pseudoelastic implant material Nitinol (NiTi) with adipose derived stem cells (ASCs) opens new opportunities, as ASCs are able to differentiate osteogenically and therefore enhance osseointegration of implants. Due to limited knowledge about the effects of NiTi-structures manufactured by selective laser melting (SLM) on ASCs the study started with an evaluation of cytocompatibility followed by the investigation of the use of SLM-generated 3-dimensional NiTi-structures preseeded with ASCs as osteoimplant model. In this study we could demonstrate for the first time that osteogenic differentiation of ASCs can be induced by implant-mediated mechanical stimulation without support of osteogenic cell culture media. By use of an innovative implant design and synthesis via SLM-technique we achieved high rates of vital cells, proper osteogenic differentiation and mechanically loadable NiTi-scaffolds could be achieved.

  11. Fabrication of NiTi shape memory alloy by Micro-FAST

    Directory of Open Access Journals (Sweden)

    Huang Kunlan

    2015-01-01

    Full Text Available A NiTi shape memory alloy, known as nitinol, has been intensively studied for last five decades. The NiTi alloy with large size is commonly produced by vacuum sintering, thermal explosion mode of self-propagating high-temperature synthesis (TE-SHS and spark plasma sintering (SPS. These methods are, however, rarely utilized for the forming of miniature and micro-sized components and have their own limits and disadvantages, such as long process chains and low efficiency with the processes. In the study reported in this paper, an innovation in rapid powder consolidation technology, called Micro-FAST (combining micro-forming and electric-current activated sintering techniques (FAST is introduced for the forming of micro-components in which the loose powders are loaded directly into the die, followed by electric-sintering. In the study, Φ4.0 mm × 4.0 mm miniature cylinders were formed with pre-alloyed NiTi powders. Sintered sample with relative density of 98.65% has been fabricated at a sintering temperature of 1150 °C in a relatively short cycle time (119.5 s. Based on the results of SEM and XRD, it was found that the densified samples with Ni3Ti, NiTi and NiTi2 phases were produced.

  12. In vitro corrosion properties and cytocompatibility of Fe-Ga alloys as potential biodegradable metallic materials.

    Science.gov (United States)

    Wang, Henan; Zheng, Yang; Liu, Jinghua; Jiang, Chengbao; Li, Yan

    2017-02-01

    The in vitro biodegradable properties and cytocompatibility of Fe-Ga alloys including Fe81Ga19, (Fe81Ga19)98B2 and (Fe81Ga19)99.5(TaC)0.5, and pure Fe were investigated for biomedical applications. The microstructure of the alloys was characterized using X-ray diffraction spectroscopy and optical microscopy. The results showed that A2 and D03 phases were detected for the three types of Fe-Ga alloys, and additional Fe2B and TaC phases were found in the (Fe81Ga19)98B2 and (Fe81Ga19)99.5(TaC)0.5 alloys, respectively. The corrosion rates of the Fe-Ga alloys were higher than that of pure Fe, as demonstrated by both potentiodynamic polarization measurements and immersion tests in simulated body fluid. The alloying element Ga lowered the corrosion potential of the Fe matrix and made it more susceptible to corrosion. Severe pitting corrosion developed on the surface of the Fe81Ga19 alloy after the addition of ternary B or TaC due to the multi-phase microstructures. The MC3T3-E1 cells exhibited good adhesion and proliferation behavior on the surfaces of the Fe-Ga alloys after culture for 4h and 24h. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Effect of low temperature annealing on the wear properties of NITINOL

    Science.gov (United States)

    Mukunda, Sriram; Nath. S, Narendra; Herbert, Mervin A.; Mukunda, P. G.

    2016-02-01

    NiTi shape memory alloy is a wonder material that is a solution looking for problems. The material finds wide biomedical applications like endodontic files for root canal treatment and cardiovascular stents. This material has rendered the surgical procedure simple compared to that with the existing Stainless Steel (SS) or titanium ones. NiTi as an endodontic file would cause less discomfort to the patients in comparison to that with far stiffer SS or titanium ones. Here nearly equi-atomic 50:50 commercial NiTi rods were subjected to low temperature aging at 300 to 450°C. The wear resistance of the as-received and the heat-treated samples was studied using adhesive wear tests on hardened steel counter face. Abrasive wear tests were run against Alumina disc to simulate the working of endodontic drills and files against dental hard and soft tissues. The abrasive wear resistance is expected to be proportional to the Vickers Hardness of the material and is high for the 450°C heat-treated sample. A correlation between the mechanical properties and microstructures of this material is attempted

  14. Preparation and Characterization of Nitinol Bone Staples for Cranio-Maxillofacial Surgery

    Science.gov (United States)

    Lekston, Z.; Stróż, D.; Jędrusik-Pawłowska, M.

    2012-12-01

    The aim of this work was to form NiTi and TiNiCo body temperature activated and superelastic staples for clinical joining of mandible and face bone fractures. The alloys were obtained by VIM technique. Hot and cold processing was applied to obtain wires of required diameters. The martensitic transformation was studied by DSC, XRD, and TEM. The shape memory effects were measured by a bend and free recovery ASTM F2082-06 test. The superelasticity was recorded in the tension stress-strain and by the three-point bending cycles in an instrument equipped with a Hottinger force transducer and LVDT. Excellent superelastic behavior of TiNiCo wires was obtained after cold working and annealing at 400-500 °C. The body temperature activated shape memory staples were applied for fixation of mandibular condyle fractures. In experiments on the skull models, fixation of the facial fractures by using shape memory and superelastic staples were compared. The superelastic staples were used in osteosynthesis of zygomatico-maxillo-orbital fractures.

  15. Crystal structure of the ternary silicide Gd2Re3Si5

    Directory of Open Access Journals (Sweden)

    Vitaliia Fedyna

    2014-12-01

    Full Text Available A single crystal of the title compound, the ternary silicide digadolinium trirhenium pentasilicide, Gd2Re3Si5, was isolated from an alloy of nominal composition Gd20Re30Si50 synthesized by arc melting and investigated by X-ray single-crystal diffraction. Its crystal structure belongs to the U2Mn3Si5 structure type. All atoms in the asymmetric lie on special positions. The Gd site has site symmetry m..; the two Mn atoms have site symmetries m.. and 2.22; the three Si atoms have site symmetries m.., ..2 and 4.. . The coordination polyhedra of the Gd atoms have 21 vertices, while those of the Re atoms are cubooctahedra and 13-vertex polyhedra. The Si atoms are arranged as tricapped trigonal prisms, bicapped square antiprisms, or 11-vertex polyhedra. The crystal structure of the title compound is also related to the structure types CaBe2Ge2 and W5Si3. It can be represented as a stacking of Gd-centred polyhedra of composition [GdSi9]. The Re atoms form infinite chains with an Re—Re distance of 2.78163 (5 Å and isolated squares with an Re—Re distance of 2.9683 (6 Å.

  16. Enhanced formic acid electro-oxidation reaction on ternary Pd-Ir-Cu/C catalyst

    Science.gov (United States)

    Chen, Jinwei; Zhang, Jie; Jiang, Yiwu; Yang, Liu; Zhong, Jing; Wang, Gang; Wang, Ruilin

    2015-12-01

    Aim to further reduce the cost of Pd-Ir for formic acid electro-oxidation (FAEO), the Cu was used to construct a ternary metallic alloy catalyst. The prepared catalysts are characterized using XRD, TGA, EDX, TEM, XPS, CO-stripping, cyclic voltammetry and chronoamperometry. It is found that the Pd18Ir1Cu6 nanoparticles with a mean size of 3.3 nm are highly dispersed on carbon support. Componential distributions on catalyst are consistent with initial contents. Electrochemical measurements show that the PdIrCu/C catalyst exhibits the highest activity for FAEO. The mass activity of Pd in Pd18Ir1Cu6/C at 0.16 V (vs. SCE) is about 1.47, 1.62 and 2.08 times as high as that of Pd18Cu6/C, Pd18Ir1/C and Pd/C, respectively. The activity enhancement of PdIrCu/C should be attributed to the weakened CO adsorption strength and the removal of adsorbed intermediates at lower potential with the addition of Cu and Ir.

  17. Influence of tin additions on the precipitation processes in a Cu-Ni-Zn alloys; Influencia de la adicion de estano en el proceso de precipitacion en una aleacion de Cu-Ni-Zn

    Energy Technology Data Exchange (ETDEWEB)

    Donoso, E. C.; Dianez, M. J.; Criado, J. M.; Espinoza, R.; Mosquera, E.

    2016-05-01

    The influence of 1.1 wt% tin additions on the precipitation hardening of Cu-11 wt% Ni-20 wt% Zn alloy was studied by Differential Scanning Calorimetry (DSC), microhardeness measurements and High Resolution Transmission Electron Microscopy (HRTEM). The calorimetric curves, in the range of temperatures analyzed, show the presence of two exothermic reactions in the ternary alloy, associated to the short-range-order development assisted by migration of excess vacancies. On the other hand, one exothermic and one endothermic reaction are observed in the quaternary alloy, associated to the formation and dissolution of Cu{sub 2}NiZn precipitates, respectively. It has been show that an addition of 1.1% tin plays an important role in the formation of Cu{sub 2}NiZn precipitates, responsible for the precipitation hardening of the ternary alloy. (Author)

  18. In Situ Synthesis of Al-Si-Cu Alloy During Brazing Process and Mechanical Property of Brazing Joint

    OpenAIRE

    LONG Wei-min; LU Quan-bin; He, Peng; XUE Song-bai; Wu, Ming-Fang; Xue, Peng

    2016-01-01

    The Al-Si-Cu alloy system is considered to be a promising choice of filler metal for aluminium alloys brazing due to its high strength and low melting point. The greatest obstacle is its lack of plastic forming ability and being difficult to be processed by conventional methods. This disadvantage is ascribed to the considerable amount of brittle CuAl2 intermetallic compound which forms when alloy composition is around the ternary eutectic point. In order to overcome this deficiency, authors o...

  19. Structural, electric and kinetic parameters of ternary alloys of GeSbTe

    Energy Technology Data Exchange (ETDEWEB)

    Morales-Sanchez, E. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Queretaro, Libramiento Norponiente 2000, Ap. Postal 13, Juriquilla, Queretaro, C. P. 76230, (Mexico)]. E-mail: m6007@ciateq.net.mx; Prokhorov, E.F. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Queretaro, Libramiento Norponiente 2000, Ap. Postal 13, Juriquilla, Queretaro, C. P. 76230, (Mexico); Gonzalez-Hernandez, J. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Queretaro, Libramiento Norponiente 2000, Ap. Postal 13, Juriquilla, Queretaro, C. P. 76230, (Mexico); Mendoza-Galvan, A. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Queretaro, Libramiento Norponiente 2000, Ap. Postal 13, Juriquilla, Queretaro, C. P. 76230, (Mexico)

    2005-01-03

    Thin amorphous films of GeSbTe have been widely employed in the technology used for phase change optical memory or compact disks. In this article, we report on measurements of resistance, transmittance, and X-ray diffraction in thin films with stoichiometric compositions of Ge{sub 1}Sb{sub 4}Te{sub 7}, Ge{sub 1}Sb{sub 2}Te{sub 4}, Ge{sub 2}Sb{sub 2}Te{sub 5}, and Ge{sub 4}Sb{sub 1}Te{sub 5.} The resistivity, lattice constant, and the temperature at which transformation from the amorphous phase to the cubic crystalline structure occurs were calculated for each stoichiometric composition, and the energy activation was determined, applying Kissinger's model. It was found that the Ge{sub 4}Sb{sub 1}Te{sub 5} composition has the highest crystallization temperature (425 K), the highest resistivity (0.178 {omega} cm), the greatest E{sub a} (3.09 eV), and the lowest lattice constant (a=5.975 A) in the cubic phase at 170 deg C.

  20. Influence of indium clustering on the band structure of semiconducting ternary and quaternarynitride alloys

    DEFF Research Database (Denmark)

    Gorczyca,, I.; Łepkowski, S. P.; Suski, T.

    2009-01-01

    and atomic arrangements are examined. Particular attention is paid to the magnitude of and trends in bowing of the band gaps. Indium composition fluctuation (clustering) is simulated by different distributions of In atoms and it is shown that it strongly influences the band gaps. The gaps are considerably...

  1. A Hydrogen-Deuterium Exchange Study on Nickel-based Binary-Ternary Amorphous and Crystalline Membranes

    Science.gov (United States)

    Adibhatla, Anasuya

    to determine the heat of hydrogen absorption and desorption on the alloy surface. Electrochemical Impedance Spectroscopy was conducted on the membranes to determine the surface resistance and it was found that Ni64Zr36 as-spun ribbon displayed highest resistance while Ni60Ta20Zr20 showed lowest resistance. Absorption studies on Ni60V 40 binary alloy and Ni60V20Zr20 ternary alloy indicated that the addition of Zr to these non-coated alloys increased the hydrogen solubility in the bulk. SEM and TEM analyses showed the presence of possible nano crystalline phases in Ni64Zr36 membrane. XRD and SEM studies conducted on post treated samples showed the possible phase segregation of Ni and ZrO2. Ni60Nb40 did not show any phase transformations after hydrogen heat treated unlike its ternary composition, Ni60Nb20Zr20. It is noteworthy to mention that bubbles were observed during SEM on Ni 64Zr36 post-treated sample on the surface due to possible hydrogen trapping and subsequent release of hydrogen gas.

  2. Development of Combinatorial Methods for Alloy Design and Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Pharr, George M.; George, Easo P.; Santella, Michael L

    2005-07-01

    The primary goal of this research was to develop a comprehensive methodology for designing and optimizing metallic alloys by combinatorial principles. Because conventional techniques for alloy preparation are unavoidably restrictive in the range of alloy composition that can be examined, combinatorial methods promise to significantly reduce the time, energy, and expense needed for alloy design. Combinatorial methods can be developed not only to optimize existing alloys, but to explore and develop new ones as well. The scientific approach involved fabricating an alloy specimen with a continuous distribution of binary and ternary alloy compositions across its surface--an ''alloy library''--and then using spatially resolved probing techniques to characterize its structure, composition, and relevant properties. The three specific objectives of the project were: (1) to devise means by which simple test specimens with a library of alloy compositions spanning the range interest can be produced; (2) to assess how well the properties of the combinatorial specimen reproduce those of the conventionally processed alloys; and (3) to devise screening tools which can be used to rapidly assess the important properties of the alloys. As proof of principle, the methodology was applied to the Fe-Ni-Cr ternary alloy system that constitutes many commercially important materials such as stainless steels and the H-series and C-series heat and corrosion resistant casting alloys. Three different techniques were developed for making alloy libraries: (1) vapor deposition of discrete thin films on an appropriate substrate and then alloying them together by solid-state diffusion; (2) co-deposition of the alloying elements from three separate magnetron sputtering sources onto an inert substrate; and (3) localized melting of thin films with a focused electron-beam welding system. Each of the techniques was found to have its own advantages and disadvantages. A new and very

  3. Thermodynamic calculations in ternary titanium–aluminium–manganese system

    Directory of Open Access Journals (Sweden)

    ANA I. KOSTOV

    2008-04-01

    Full Text Available Thermodynamic calculations in the ternary Ti–Al–Mn system are shown in this paper. The thermodynamic calculations were performed using the FactSage thermochemical software and database, with the aim of determining thermodynamic properties, such as activities, coefficient of activities, partial and integral values of the enthalpies and Gibbs energies of mixing and excess energies at two different temperatures: 2000 and 2100 K. Bearing in mind that no experimental data for the Ti–Al–Mn ternary system have been obtained or reported. The obtained results represent a good base for further thermodynamic analysis and may be useful as a comparison with some future critical experimental results and thermodynamic optimization of this system.

  4. A New Multifunctional Sensor for Measuring Concentrations of Ternary Solution

    Science.gov (United States)

    Wei, Guo; Shida, Katsunori

    This paper presents a multifunctional sensor with novel structure, which is capable of directly sensing temperature and two physical parameters of solutions, namely ultrasonic velocity and conductivity. By combined measurement of these three measurable parameters, the concentrations of various components in a ternary solution can be simultaneously determined. The structure and operation principle of the sensor are described, and a regression algorithm based on natural cubic spline interpolation and the least square method is adopted to estimate the concentrations. The performances of the proposed sensor are experimentally tested by the use of ternary aqueous solution of sodium chloride and sucrose, which is widely involved in food and beverage industries. This sensor could prove valuable as a process control sensor in industry fields.

  5. Cohesion energy calculations for ternary ionic novel crystals

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez P, G.; Cabrera, E. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, A.P. 20-364, 01000 Mexico D.F. (Mexico); Mijangos, R.R. [Centro de Investigacion en Fisica, Universidad de Sonora, A.P. 5-88, 83190 Hermosillo, Sonora (Mexico); Valdez, E. [Escuela Nacional de Estudios Profesionales Acatlan, Universidad Nacional Autonoma de Mexico, Santa Cruz Acatlan, Naucalpan (Mexico); Duarte, C. [Departamento de Geologia, Universidad de Sonora, 83000 Hermosillo, Sonora (Mexico)

    2001-07-01

    The present work calculates the value of the link energy of a crystalline ternary structure newly formed by alkali halides. The ternary structure prepared with different concentrations of KCl{sub x}KBrRbCl{sub 2} maintains a very good miscibility and stability. The calculation is based on the use of a generalization of the Vegard law (which generally is valid for binary compounds) for calculating the values of the lattice constant and the repulsive m exponent. The value of the lattice parameter given by X-ray diffractometry agrees with the close approximation of the calculated value of the method used. It also compares the value of energy cohesion obtained by the Born expression with more complex approximations. (Author)

  6. Optical Properties of Silver Aluminium Sulphide Ternary Thin Films ...

    African Journals Online (AJOL)

    Ternary thin films of Silver Aluminium Sulphide (AgAlS2) have been prepared by chemical bath deposition techniques. Aqueous solution of 41.5 mls containing AgNO3, Al2(SO4)3, thiourea and EDTA was used, where AgNO3, Al2(SO4)3, thiourea were the source of Ag+, Al+ and S- respectively and EDTA was used as a ...

  7. Evaluation of Griseofulvin Binary and Ternary Solid Dispersions with HPMCAS

    OpenAIRE

    Al-Obaidi, Hisham; Buckton, Graham

    2009-01-01

    The stability and dissolution properties of griseofulvin binary and ternary solid dispersions were evaluated. Solid dispersions of griseofulvin and hydroxypropyl methylcellulose acetate succinate (HPMCAS) were prepared using the spray drying method. A third polymer, poly[N-(2-hydroxypropyl)methacrylate] (PHPMA), was incorporated to investigate its effect on the interaction of griseofulvin with HPMCAS. In this case, HPMCAS can form H bonds with griseofulvin directly; the addition of PHPMA to t...

  8. Some new quasi-twisted ternary linear codes

    Directory of Open Access Journals (Sweden)

    Rumen Daskalov

    2015-09-01

    Full Text Available Let [n, k, d]_q code be a linear code of length n, dimension k and minimum Hamming distance d over GF(q. One of the basic and most important problems in coding theory is to construct codes with best possible minimum distances. In this paper seven quasi-twisted ternary linear codes are constructed. These codes are new and improve the best known lower bounds on the minimum distance in [6].

  9. Theoretical prediction of topological insulator in ternary rare earth chalcogenides

    OpenAIRE

    Yan, Binghai; Zhang, Hai-Jun; Liu, Chao-Xing; Qi, Xiao-Liang; Frauenheim, Thomas; Zhang, Shou-Cheng

    2010-01-01

    A new class of three-dimensional topological insulator, ternary rare earth chalcogenides, is theoretically investigated with ab initio calculations. Based on both bulk band structure analysis and the direct calculation of topological surface states, we demonstrate that LaBiTe3 is a topological insulator. La can be substituted by other rare earth elements, which provide candidates for novel topological states such as quantum anomalous Hall insulator, axionic insulator and topological Kondo ins...

  10. Optical critical points of Si x Ge1‑x‑y Sn y alloys with high Si content

    Science.gov (United States)

    Fischer, Inga A.; Berrier, Audrey; Hornung, Florian; Oehme, Michael; Zaumseil, Peter; Capellini, Giovanni; von den Driesch, Nils; Buca, Dan; Schulze, Jörg

    2017-12-01

    We extend the analysis of optical transition energies above 1.5 eV in ternary Si x Ge1‑x‑y Sn y alloys grown by molecular beam epitaxy to a composition range in which 1‑x‑y is as low as 0.405. Simple models for transition energies assume a quadratic dependence on material content. Comparing our results to existing predictions of the transition energies based on results obtained from samples with much lower Si and Sn content, however, we find a significant disagreement between experiment and theory, indicating that the assumption of a quadratic dependence might not be valid for the entire composition range of the ternary alloy.

  11. Ternary Ag/epoxy adhesive with excellent overall performance.

    Science.gov (United States)

    Ji, Yan-Hong; Liu, Yu; Huang, Gui-Wen; Shen, Xiao-Jun; Xiao, Hong-Mei; Fu, Shao-Yun

    2015-04-22

    Excellent electrical conductivity (EC) generally conflicts with high lap shear strength (LSS) for electrically conductive adhesives (ECAs) since EC increases while LSS decreases with increasing conductive filler content. In this work, the ECAs with the excellent overall performance are developed based on the ternary hybrid of Ag microflakes (Ag-MFs), Ag nanospheres (Ag-NSs), and Ag nanowires (Ag-NWs). First, a low silver content adhesive system is determined. Then, the effects of the relative contents of Ag fillers on the EC and the LSS are studied. It is shown that a small amount of Ag-NSs or Ag-NWs can dramatically improve the EC for the Ag-MF/epoxy adhesives. The Ag-NSs and Ag-NWs with appropriate contents have a synergistic effect in improving the EC. Meanwhile, the LSS of the as-prepared adhesive with the appropriate Ag contents reaches an optimal value. Both the EC and the LSS of the as-prepared ternary hybrid ECA with a low content of 40 wt % Ag are higher than those of the commercial ECAs filled with the Ag-MF content over 60 wt %. Finally, the ternary hybrid ECA with the optimal formulation is shown to be promising for printing the radio frequency identification tag antennas as an immediate application example.

  12. Valence band electronic structure of Pd based ternary chalcogenide superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Lohani, H. [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005 (India); Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400085 (India); Mishra, P. [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005 (India); Goyal, R.; Awana, V.P.S. [National Physical Laboratory(CSIR), Dr. K. S. Krishnan Road, New Delhi 110012 (India); Sekhar, B.R., E-mail: sekhar@iopb.res.in [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005 (India); Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400085 (India)

    2016-12-15

    Highlights: • VB Photoemission study and DFT calculations on Pd based ternary superconductors are presented. • Nb{sub 2}Pd{sub 0.95}S{sub 5} shows a temperature dependent pseudogap. • VB spectral features of ternary superconductors are correlated to their structural geometry. - Abstract: We present a comparative study of the valence band electronic structure of Pd based ternary chalcogenide superconductors Nb{sub 2}Pd{sub 0.95}S{sub 5}, Ta{sub 2}Pd{sub 0.97}S{sub 6} and Ta{sub 2}Pd{sub 0.97}Te{sub 6} using experimental photoemission spectroscopy and density functional based theoretical calculations. We observe a qualitatively similarity between valence band (VB) spectra of Nb{sub 2}Pd{sub 0.95}S{sub 5} and Ta{sub 2}Pd{sub 0.97}S{sub 6}. Further, we find a pseudogap feature in Nb{sub 2}Pd{sub 0.95}S{sub 5} at low temperature, unlike other two compounds. We have correlated the structural geometry with the differences in VB spectra of these compounds. The different atomic packing in these compounds could vary the strength of inter-orbital hybridization among various atoms which leads to difference in their electronic structure as clearly observed in our DOS calculations.

  13. Realizing Ternary Logic in FPGAs for SWL DSP Systems

    Directory of Open Access Journals (Sweden)

    Tayeb Din

    2013-07-01

    Full Text Available Recently SWL (Short Word Length DSP (Digital Signal Processing applications has been proposed to overcome multiplier complexity that is evident in most of the digital applications. These SWL applications have been processed through sigma-delta modulation as a key element. For such applications, adder design plays vital role and can impact upon the chip area and its performance. In this paper, a ternary approach for adder tree has been proposed instead of binary that can accommodate more data with less chip-area at the cost of extra pin. The proposed ternary adder tree has been designed and developed in Quartus-II using three different design strategies namely T-gate (Ternary gate, LUT (Look Up Table and algebraic equations. Through rigorous simulation it was found that T-gate technique results in superior performance, an average of 23.5 and 33% improvement compared to the same adder structure based on Boolean Algebraic Equation and LUT, respectively. The proposed adder design would benefit the efficient implementation of SWL applications.

  14. Rhenium alloying of tungsten heavy alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bose, A.; Jerman, G.; German, R.M.

    1989-06-01

    Alloying experiments have been performed using rhenium additions to a classic 90 mass% tungsten heavy alloy. The mixed powder system was liquid phase sintered to full density at 1500/sup 0/C in 60 min. The rhenium modified alloys exhibited a smaller grain size, higher hardness, higher strength, and lower ductility than the unalloyed system. For an alloy with a composition of 84W-6Re-8Ni-2Fe, the sintered density was 17,4 Mg/m/sup 3/ with a yield strength of 815 MPa, tensile strength of 1180 MPa, and elongation to failure of 13%. This property combination results from the aggregate effects of grain size reduction and solid solution hardening due to rhenium. In the unalloyed system these properties require post-sintering swaging and aging; thus, alloying with rhenium is most attractive for applications where netshaping is desired, such as by powder injection molding. (orig.).

  15. Rhenium alloying of tungsten heavy alloys

    Energy Technology Data Exchange (ETDEWEB)

    German, R.M.; Bose, A.; Jerman, G.

    1989-01-01

    Alloying experiments were performed using rhenium additions to a classic 90 mass % tungsten heavy alloy. The mixed-powder system was liquid phase sintered to full density at 1500 C in 60 min The rhenium-modified alloys exhibited a smaller grain size, higher hardness, higher strength, and lower ductility than the unalloyed system. For an alloy with a composition of 84W-6Re-8Ni-2Fe, the sintered density was 17, 4 Mg/m{sup 3} with a yield strength of 815 MPa, tensile strength of 1180 MPa, and elongation to failure of 13%. This property combination results from the aggregate effects of grain size reduction and solid solution hardening due to rhenium. In the unalloyed system these properties require post-sintering swaging and aging; thus, alloying with rhenium is most attractive for applications where net shaping is desired, such as by powder injection molding.

  16. Nickel alloys development-Inconel alloys development

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-07-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Santana M, J.S

    2003-07-01

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

  18. Design of high density gamma-phase uranium alloys for LEU dispersion fuel applications.

    Energy Technology Data Exchange (ETDEWEB)

    Hofman, G. L.

    1998-10-19

    Uranium alloys are candidates for the fuel phase in aluminum matrix dispersion fuels requiring high uranium loading. Certain uranium alloys have been shown to have good irradiation performance at intermediate burnup. Previous studies have shown that acceptable fission gas swelling behavior and fuel-aluminum interaction is possible only if the fuel alloy can be maintained in the high temperature body-centered-cubic {gamma}-phase during fabrication and irradiation, i.e., at temperatures at which {alpha}-U is the equilibrium phase. Transition metals in Groups V through VIII are known to allow metastable retention of the gamma phase below the equilibrium isotherm. These metals have varying degrees of effectiveness in stabilizing the gamma phase. Certain alloys are metastable for very long times at the relatively low fuel temperatures seen in research reactor operation. In this paper, the existing data on the gamma stability of binary and ternary uranium alloys is analyzed. The mechanism and kinetics of decomposition of the gamma phase are assessed with the help of metal alloy theory. Alloys with the highest possible uranium content, good gamma-phase stability, and good neutronic performance are identified for further metallurgical studies and irradiation tests. Results from theory will be compared with experimentally generated data.

  19. Neural network potential for Al-Mg-Si alloys

    Science.gov (United States)

    Kobayashi, Ryo; Giofré, Daniele; Junge, Till; Ceriotti, Michele; Curtin, William A.

    2017-10-01

    The 6000 series Al alloys, which include a few percent of Mg and Si, are important in automotive and aviation industries because of their low weight, as compared to steels, and the fact their strength can be greatly improved through engineered precipitation. To enable atomistic-level simulations of both the processing and performance of this important alloy system, a neural network (NN) potential for the ternary Al-Mg-Si has been created. Training of the NN uses an extensive database of properties computed using first-principles density functional theory, including complex precipitate phases in this alloy. The NN potential accurately reproduces most of the pure Al properties relevant to the mechanical behavior as well as heat of solution, solute-solute, and solute-vacancy interaction energies, and formation energies of small solute clusters and precipitates that are required for modeling the early stage of precipitation and mechanical strengthening. This success not only enables future detailed studies of Al-Mg-Si but also highlights the ability of NN methods to generate useful potentials in complex alloy systems.

  20. High strength alloys

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-06-05

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

  1. 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.

  2. Information on individual interfaces in ternary polymer blends from positron annihilation lifetime studies

    Science.gov (United States)

    Meghala, D.; Ramya, P.; Pasang, T.; Ravikumar, H. B.; Ranganathaiah, C.

    2012-06-01

    Positron Annihilation Lifetime Spectroscopy has been used to determine the free volume content in the ternary blends of SAN/EVA/PVC. The method of deriving hydrodynamic interaction parameter (α) in binary polymer blends was modified for ternary polymer blend system characterized by three distinct interfaces. Each interface characterized, is associated with an α and its assertion for the ternary blend are compared with available literature data.

  3. Development of a high density fuel based on uranium-molybdenum alloys with high compatibility in high temperatures; Desenvolvimento de um combustivel de alta densidade a base das ligas uranio-molibdenio com alta compatibilidade em altas temperaturas

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Fabio Branco Vaz de

    2008-07-01

    This work has as its objective the development of a high density and low enriched nuclear fuel based on the gamma-UMo alloys, for utilization where it is necessary satisfactory behavior in high temperatures, considering its utilization as dispersion. For its accomplishment, it was started from the analysis of the RERTR ('Reduced Enrichment for Research and Test Reactors') results and some theoretical works involving the fabrication of gamma-uranium metastable alloys. A ternary addition is proposed, supported by the properties of binary and ternary uranium alloys studied, having the objectives of the gamma stability enhancement and an ease to its powder fabrication. Alloys of uranium-molybdenum were prepared with 5 to 10% Mo addition, and 1 and 3% of ternary, over a gamma U7Mo binary base alloy. In all the steps of its preparation, the alloys were characterized with the traditional techniques, to the determination of its mechanical and structural properties. To provide a process for the alloys powder obtention, its behavior under hydrogen atmosphere were studied, in thermo analyser-thermo gravimeter equipment. Temperatures varied from the ambient up to 1000 deg C, and times from 15 minutes to 16 hours. The results validation were made in a semi-pilot scale, where 10 to 50 g of powders of some of the alloys studied were prepared, under static hydrogen atmosphere. Compatibility studies were conducted by the exposure of the alloys under oxygen and aluminum, to the verification of possible reactions by means of differential thermal analysis. The alloys were exposed to a constant heat up to 1000 deg C, and their performances were evaluated in terms of their reaction resistance. On the basis of the results, it was observed that ternary additions increases the temperatures of the reaction with aluminum and oxidation, in comparison with the gamma UMo binaries. A set of conditions to the hydration of the alloys were defined, more restrictive in terms of temperature

  4. 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.

  5. 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.)

  6. Microstructural development during solidification of stainless steel alloys

    Science.gov (United States)

    Elmer, J. W.; Allen, S. M.; Eagar, T. W.

    1989-10-01

    The microstructures that develop during the solidification of stainless steel alloys are related to the solidification conditions and the specific alloy composition. The solidification conditions are determined by the processing method, i.e., casting, welding, or rapid solidification, and by parametric variations within each of these techniques. One variable that has been used to characterize the effects of different processing conditions is the cooling rate. This factor and the chemical composition of the alloy both influence (1) the primary mode of solidification, (2) solute redistribution and second-phase formation during solidification, and (3) the nucleation and growth behavior of the ferrite-to-austenite phase transformation during cooling. Consequently, the residual ferrite content and the microstructural morphology depend on the cooling rate and are governed by the solidification process. This paper investigates the influence of cooling rate on the microstructure of stainless steel alloys and describes the conditions that lead to the many microstructural morphologies that develop during solidification. Experiments were performed on a series of seven high-purity Fe-Ni-Cr alloys that spanned the line of twofold saturation along the 59 wt pct Fe isopleth of the ternary alloy system. High-speed electron-beam surface-glazing was used to melt and resolidify these alloys at scan speeds up to 5 m/s. The resulting cooling rates were shown to vary from 7°C/s to 7.5×106°C/s, and the resolidified melts were analyzed by optical metallographic methods. Five primary modes of solidification and 12 microstructural morphologies were characterized in the resolidified alloys, and these features appear to be a complete “set” of the possible microstructures for 300-series stainless steel alloys. The results of this study were used to create electron-beam scan speed vs composition diagrams, which can be used to predict the primary mode of solidification and the

  7. Liquid-liquid equilibria for binary and ternary polymer solutions with PC-SAFT

    DEFF Research Database (Denmark)

    Lindvig, Thomas; Michelsen, Michael Locht; Kontogeorgis, Georgios

    2004-01-01

    are used for investigating the correlative and predictive capabilities of the thermodynamic model PC-SAFT. The investigation shows that the model correlates well experimental LLE data for binary as well as ternary systems but further predicts the behavior of the ternary systems with reasonably good......Two algorithms for evaluating liquid-liquid equilibria (LLE) for binary and ternary polymer solutions are presented. The binary algorithm provides the temperature versus concentration cloud-point curve at fixed pressure, whereas the ternary algorithm provides component 1 versus component 2...

  8. Computational thermodynamics aided design of novel ferritic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ying [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Chen, Tianyi [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Tan, Lizhen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-06-30

    With the aid of computational thermodynamics, Ni was identified to suppress the liquidus temperature of Fe2Zr and four Fe-Cr-Ni-Zr alloys were designed to study the Ni effect on the phase stability of Fe2Zr laves_phase. These alloys were fabricated through traditional arc-metling, followed by annealing at 1000 C for 336 hours and 700 C for 1275 hours. The microstructure were examined and characterized by SEM BSE image, EDS compositional mapping and point scan, XRD and TEM analysis. The major results were summarized below: 1)For investigated alloys with 12wt% Cr, 3~6wt% Zr and 3~9 wt%Ni, the phases in equilibrium with the BCC phase are C15_Laves phase, Fe23Zr6 phase. The volume fraction of intermetallic phases increases with Ni and Zr contents. 2)Instead of (Fe,Cr)2Zr C14_Laves phase, Ni stabilizes the C15_Laves structure in Fe-Cr-Ni-Zr alloys by substituting Fe and Cr atoms with Ni atoms in the first sublattice. 3)Fe23Zr6, that is metastable in the Fe-Cr-Zr ternary, is also stabilized by Ni addition. 4)Ni7Zr2 phase was observed in samples with high Ni/Zr ratio. Extensive solubility of Fe was identified in the phase. The microstructural and composition results obtained from this study will be incorportated into the the Fe-Cr-Ni-Zr database. The current samples will be subjected to ion irradiaition to be compared with those results for Fe-Cr-Zr alloys. Additional alloys will be designed to form (Fe,Cr,Ni)2Zr nanoprecipitates for further studies.

  9. Temperature dependence of the photoluminescence polarization of ordered III-V semiconductor alloys

    Energy Technology Data Exchange (ETDEWEB)

    Prutskij, T.; Makarov, N. [Instituto de Ciencias, BUAP, Privada 17 Norte, No 3417, col. San Miguel Huyeotlipan, 72050 Puebla, Pue. (Mexico); Attolini, G. [IMEM/CNR, Parco Area delle Scienze 37/A, 43010 Parma (Italy)

    2016-03-21

    We studied the linear polarization of the photoluminescence (PL) emission of atomically ordered GaInAsP and GaInP alloys with different ordering parameters in the temperature range from 10 to 300 K. The epitaxial layers of these alloys were grown on GaAs and Ge (001) substrates by metal organic vapor phase epitaxy. The polarization of the PL emission propagating along different crystallographic axes depends on the value of biaxial strain in the layer and changes with temperature. We calculated the PL polarization patterns for different propagation directions as a function of biaxial strain using an existing model developed for ternary atomically ordered III-V alloys. Comparing the calculated PL polarization patterns with those obtained experimentally, we separated the variation of the PL polarization due to change of biaxial strain with temperature.

  10. Mg amorphous alloys for biodegradable implants; Ligas amorfas de magnesio utilizadas em implantes consumiveis

    Energy Technology Data Exchange (ETDEWEB)

    Danez, G.P., E-mail: gabidanez@hotmail.co [Universidade Federal de Sao Carlos (PPG-CEMUFSCar), SP (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais; Koga, G.Y.; Tonucci, S.; Bolfarini, C.; Kiminami, C.S.; Botta Filho, W.J. [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais

    2010-07-01

    The use of implants made from amorphous alloys magnesium-based with additions of zinc and calcium are promising. Properties such as biocompatibility, low density, high mechanical strength, low modulus (as compared to alloys such as stainless steel and titanium), corrosion resistance and wear resistance make it attractive for use in implants. Moreover, the by-products of corrosion and wear are not toxic and may contribute to fixation. Aiming to understand the tendency of this amorphous ternary (Mg-Zn-Ca) and expand the information about this system, this work involved the use of the topological criterion of instability ({lambda}) and the criterion of electronegativity ({Delta}e) to the choice of compositions. The alloys were processed into wedge-shaped and analyzed structurally and in X-ray diffraction and scanning electron microscopy. (author)

  11. Corrosion behavior in high-temperature pressurized water of Zircaloy-4 joints brazed with Zr-Cu-based amorphous filler alloys

    Science.gov (United States)

    Lee, Jung Gu; Lee, Gyoung-Ja; Park, Jin-Ju; Lee, Min-Ku

    2017-05-01

    The compositional effects of ternary Zr-Cu-X (X: Al, Fe) amorphous filler alloys on galvanic corrosion susceptibility in high-temperature pressurized water were investigated for Zircaloy-4 brazed joints. Through an Al-induced microgalvanic reaction that deteriorated the overall nobility of the joint, application of the Zr-Cu-Al filler alloy caused galvanic coupling to develop readily between the Al-bearing joint and the Al-free base metal, finally leading to massive localized corrosion of the joint. Contrastingly, joints prepared with a Zr-Cu-Fe filler alloy showed excellent corrosion resistance comparable to that of the Zircaloy-4 base metal, since the Cu and Fe elements forming fine intermetallic particles with Zr did not influence the electrochemical stability of the resultant joints. The present results demonstrate that Fe is a more suitable alloying element than Al for brazing filler alloys subjected to high-temperature corrosive environments.

  12. Development of High-Strength High-Temperature Cast Al-Ni-Cr Alloys Through Evolution of a Novel Composite Eutectic Structure

    Science.gov (United States)

    Pandey, P.; Kashyap, S.; Tiwary, C. S.; Chattopadhyay, K.

    2017-12-01

    Aiming to develop high-strength Al-based alloys with high material index (strength/density) for structural application, this article reports a new class of multiphase Al alloys in the Al-Ni-Cr system that possess impressive room temperature and elevated temperature (≥ 200 °C) mechanical properties. The ternary eutectic and near eutectic alloys display a complex microstructure containing intermetallic phases displaying hierarchically arranged plate and rod morphologies that exhibit extraordinary mechanical properties. The yield strengths achieved at room temperatures are in excess of 350 MPa with compressive plastic strains of more than 30 pct (without fracturing) for these alloys. The stability of the complex microstructure also leads to a yield stress of 191 ± 8 to 232 ± 5 MPa at 250 °C. It is argued that the alloys derive their high strength and impressive plasticity through synergic effects of refined nanoeutectics of two different morphologies forming a core shell type of architecture.

  13. Lanthanum nickel aluminum alloy

    Science.gov (United States)

    Gruen, Dieter M.; Mendelsohn, Marshall H.; Dwight, Austin E.

    1979-01-01

    A ternary intermetallic compound capable of reversible sorption of hydrogen having the chemical formula LaNi.sub.5-x Al.sub.x, where x is in the range of about 0.01 to 1.5 and the method of storing hydrogen using the intermetallic compound.

  14. Atomistic Method Applied to Computational Modeling of Surface Alloys

    Science.gov (United States)

    Bozzolo, Guillermo H.; Abel, Phillip B.

    2000-01-01

    The formation of surface alloys is a growing research field that, in terms of the surface structure of multicomponent systems, defines the frontier both for experimental and theoretical techniques. Because of the impact that the formation of surface alloys has on surface properties, researchers need reliable methods to predict new surface alloys and to help interpret unknown structures. The structure of surface alloys and when, and even if, they form are largely unpredictable from the known properties of the participating elements. No unified theory or model to date can infer surface alloy structures from the constituents properties or their bulk alloy characteristics. In spite of these severe limitations, a growing catalogue of such systems has been developed during the last decade, and only recently are global theories being advanced to fully understand the phenomenon. None of the methods used in other areas of surface science can properly model even the already known cases. Aware of these limitations, the Computational Materials Group at the NASA Glenn Research Center at Lewis Field has developed a useful, computationally economical, and physically sound methodology to enable the systematic study of surface alloy formation in metals. This tool has been tested successfully on several known systems for which hard experimental evidence exists and has been used to predict ternary surface alloy formation (results to be published: Garces, J.E.; Bozzolo, G.; and Mosca, H.: Atomistic Modeling of Pd/Cu(100) Surface Alloy Formation. Surf. Sci., 2000 (in press); Mosca, H.; Garces J.E.; and Bozzolo, G.: Surface Ternary Alloys of (Cu,Au)/Ni(110). (Accepted for publication in Surf. Sci., 2000.); and Garces, J.E.; Bozzolo, G.; Mosca, H.; and Abel, P.: A New Approach for Atomistic Modeling of Pd/Cu(110) Surface Alloy Formation. (Submitted to Appl. Surf. Sci.)). Ternary alloy formation is a field yet to be fully explored experimentally. The computational tool, which is based on

  15. The Lattice Compatibility Theory: Arguments for Recorded I-III-O2 Ternary Oxide Ceramics Instability at Low Temperatures beside Ternary Telluride and Sulphide Ceramics

    Directory of Open Access Journals (Sweden)

    K. Boubaker

    2013-01-01

    Full Text Available Some recorded behaviours differences between chalcopyrite ternary oxide ceramics and telluride and sulphides are investigated in the framework of the recently proposed Lattice Compatibility Theory (LCT. Alterations have been evaluated in terms of Urbach tailing and atomic valence shell electrons orbital eigenvalues, which were calculated through several approximations. The aim of the study was mainly an attempt to explain the intriguing problem of difficulties of elaborating chalcopyrite ternary oxide ceramics (I-III-O2 at relatively low temperatures under conditions which allowed crystallization of ternary telluride and sulphides.

  16. The Effect of Sb Addition on Sn-Based Alloys for High-Temperature Lead-Free Solders: an Investigation of the Ag-Sb-Sn System

    Science.gov (United States)

    Li, D.; Delsante, S.; Watson, A.; Borzone, G.

    2012-01-01

    Today there is renewed interest in alloys belonging to the Sb-Sn-X (X = Cu, Ag, Bi) ternary systems and their phase equilibria, phase transformations, and thermodynamic properties because of their possible use as high-temperature lead-free solders in the electronics industry. The integral mixing enthalpy of Ag-Sb-Sn liquid alloys has been measured along five different sections (Ag0.25Sn0.75, Ag0.50Sn0.50, Sb0.30Sn0.70, Sb0.50Sn0.50, and Sb0.70Sn0.30) at 530°C, 600°C, and 630°C, using a high-temperature Calvet calorimeter by dropping pure elements (Ag or Sb) in the binary alloy liquid bath. The ternary extrapolation models of Muggianu and Toop were used to calculate the integral enthalpy of mixing and to compare measured and extrapolated values. Selected ternary alloys have been prepared for thermal investigation by using a differential scanning calorimeter at different heating/cooling rates in order to clarify the temperature of the invariant reactions and the crystallization path.

  17. In Situ Synthesis of Al-Si-Cu Alloy During Brazing Process and Mechanical Property of Brazing Joint

    Directory of Open Access Journals (Sweden)

    LONG Wei-min

    2016-06-01

    Full Text Available The Al-Si-Cu alloy system is considered to be a promising choice of filler metal for aluminium alloys brazing due to its high strength and low melting point. The greatest obstacle is its lack of plastic forming ability and being difficult to be processed by conventional methods. This disadvantage is ascribed to the considerable amount of brittle CuAl2 intermetallic compound which forms when alloy composition is around the ternary eutectic point. In order to overcome this deficiency, authors of this article proposed to synthesize Al-Si-Cu filler metal by using in situ synthesis method, and the structure and properties of brazing joints were studied. The results show that AlSi alloy is used as the wrap layer, and CuAl alloy is used as the powder core in the composite brazing wire, the two alloys have similar melting points. The machinability of the composite brazing wire is much superior to the traditional Al-Si-Cu filler metal. During the induction brazing of 3A21 alloy, when using AlSi-CuAl composite filler wire, AlSi and CuAl alloys melt almost simultaneously, then after short time holding, Al-Si-Cu braze filler is obtained, the brazing seam has uniform composition and good bonding interface, also, the shearing strength of the brazing joints is higher than the joint brazed by conventional Al-Si-Cu filler metal.

  18. Crystal Growth of Ternary Compound Semiconductors in Low Gravity Environment

    Science.gov (United States)

    Su, Ching-Hua

    2014-01-01

    A low gravity material experiment will be performed in the Material Science Research Rack (MSRR) on International Space Station (ISS). There are two sections of the flight experiment: (I) crystal growth of ZnSe and related ternary compounds, such as ZnSeS and ZnSeTe, by physical vapor transport (PVT) and (II) melt growth of CdZnTe by directional solidification. The main objective of the project is to determine the relative contributions of gravity-driven fluid flows to the compositional distribution, incorporation of impurities and defects, and deviation from stoichiometry observed in the grown crystals as results of buoyancy-driven convection and growth interface fluctuations caused by irregular fluid-flows on Earth. The investigation consists of extensive ground-based experimental and theoretical research efforts and concurrent flight experimentation. This talk will focus on the ground-based studies on the PVT crystal growth of ZnSe and related ternary compounds. The objectives of the ground-based studies are (1) obtain the experimental data and conduct the analyses required to define the optimum growth parameters for the flight experiments, (2) perfect various characterization techniques to establish the standard procedure for material characterization, (3) quantitatively establish the characteristics of the crystals grown on Earth as a basis for subsequent comparative evaluations of the crystals grown in a low-gravity environment and (4) develop theoretical and analytical methods required for such evaluations. ZnSe and related ternary compounds have been grown by vapor transport technique with real time in-situ non-invasive monitoring techniques. The grown crystals have been characterized extensively by various techniques to correlate the grown crystal properties with the growth conditions.

  19. 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.

  20. Quantifying the energetics of cooperativity in a ternary protein complex

    DEFF Research Database (Denmark)

    Andersen, Peter S; Schuck, Peter; Sundberg, Eric J

    2002-01-01

    and mathematical modeling to describe the energetics of cooperativity in a trimolecular protein complex. As a model system for quantifying cooperativity, we studied the ternary complex formed by the simultaneous interaction of a superantigen with major histocompatibility complex and T cell receptor, for which...... a structural model is available. This system exhibits positive and negative cooperativity, as well as augmentation of the temperature dependence of binding kinetics upon the cooperative interaction of individual protein components in the complex. Our experimental and theoretical analysis may be applicable...... to other systems involving cooperativity....

  1. Implementation of DFT application on ternary optical computer

    Science.gov (United States)

    Junjie, Peng; Youyi, Fu; Xiaofeng, Zhang; Shuai, Kong; Xinyu, Wei

    2018-03-01

    As its characteristics of huge number of data bits and low energy consumption, optical computing may be used in the applications such as DFT etc. which needs a lot of computation and can be implemented in parallel. According to this, DFT implementation methods in full parallel as well as in partial parallel are presented. Based on resources ternary optical computer (TOC), extensive experiments were carried out. Experimental results show that the proposed schemes are correct and feasible. They provide a foundation for further exploration of the applications on TOC that needs a large amount calculation and can be processed in parallel.

  2. A review on ternary vanadate one-dimensional nanomaterials.

    Science.gov (United States)

    Pei, Li Z; Wang, Shuai; Liu, Han D; Pei, Yin Q

    2014-01-01

    Ternary vanadate one-dimensional nanomaterials exhibit great application potential in the fields of lithium ion batteries, photocatalysis and electrochemical sensors owing to their good electrochemical and photocatalytic properties. The article reviews the recent progress and patents on the vanadate one-dimensional nanomaterials. The synthesis of the vanadate nanorods, nanobelts and nanotubes by hydrothermal method, template method and room temperature wet chemical process is demonstrated. The application of the vanadate one-dimensional nanomaterials for lithium ion batteries, electrochemical sensors and photocatalysis is discussed. The possible development direction of the vanadate one-dimensional nanomaterials for the synthesis and application is also analyzed.

  3. Low activation ferritic alloys

    Science.gov (United States)

    Gelles, D.S.; Ghoniem, N.M.; Powell, R.W.

    1985-02-07

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

  4. Ternary System with Controlled Structure: A New Strategy toward Efficient Organic Photovoltaics.

    Science.gov (United States)

    Cheng, Pei; Wang, Rui; Zhu, Jingshuai; Huang, Wenchao; Chang, Sheng-Yung; Meng, Lei; Sun, Pengyu; Cheng, Hao-Wen; Qin, Meng; Zhu, Chenhui; Zhan, Xiaowei; Yang, Yang

    2018-02-01

    Recently, a new type of active layer with a ternary system has been developed to further enhance the performance of binary system organic photovoltaics (OPV). In the ternary OPV, almost all active layers are formed by simple ternary blend in solution, which eventually leads to the disordered bulk heterojunction (BHJ) structure after a spin-coating process. There are two main restrictions in this disordered BHJ structure to obtain higher performance OPV. One is the isolated second donor or acceptor domains. The other is the invalid metal-semiconductor contact. Herein, the concept and design of donor/acceptor/acceptor ternary OPV with more controlled structure (C-ternary) is reported. The C-ternary OPV is fabricated by a sequential solution process, in which the second acceptor and donor/acceptor binary blend are sequentially spin-coated. After the device optimization, the power conversion efficiencies (PCEs) of all OPV with C-ternary are enhanced by 14-21% relative to those with the simple ternary blend; the best PCEs are 10.7 and 11.0% for fullerene-based and fullerene-free solar cells, respectively. Moreover, the averaged PCE value of 10.4% for fullerene-free solar cell measured in this study is in great agreement with the certified one of 10.32% obtained from Newport Corporation. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Using a Ternary Diagram to Display a System's Evolving Energy Distribution

    Science.gov (United States)

    Brazzle, Bob; Tapp, Anne

    2016-01-01

    A ternary diagram is a graphical representation used for systems with three components. They are familiar to mineralogists (who typically use them to categorize varieties of solid solution minerals such as feldspar) but are not yet widely used in the physics community. Last year the lead author began using ternary diagrams in his introductory…

  6. Visible and near-infrared light emitting calix[4]arene-based ternary lanthanide complexes

    NARCIS (Netherlands)

    Hebbink, G.A.; Klink, S.I.; Oude Alink, Patrick G.B.; van Veggel, F.C.J.M.

    2001-01-01

    In this article ternary lanthanide complexes consisting of a calix[4]arene unit and dibenzoylmethane (dbm) as the antenna are described. In the europium complex [(Eu)2]NO3 two solvent molecules are still coordinated to the ion, making substitution of them by the dbm antenna possible. In the ternary

  7. INTERVAL-VALUED INTUITIONISTIC FUZZY BI-IDEALS IN TERNARY SEMIRINGS

    Directory of Open Access Journals (Sweden)

    D. KRISHNASWAMY

    2016-04-01

    Full Text Available In this paper we introduce the notions of interval-valued fuzzy bi-ideal, interval-valued anti fuzzy bi-ideal and interval-valued intuitionistic fuzzy bi-ideal in ternary semirings and some of the basic properties of these ideals are investigated. We also introduce normal interval-valued intuitionistic fuzzy ideals in ternary semirings.

  8. Ternary-fission dynamics and asymmetries in reactions with polarized neutrons

    CERN Document Server

    Bunakov, V E

    2002-01-01

    Experimental results of measuring various asymmetries of charged-particles emission in ternary fission induced by polarized neutrons, namely parity nonconserving asymmetries, left-right asymmetries and triple-odd correlations are presented. It is demonstrated what kind of new information about the mechanism of ternary fission can be obtained from their analysis

  9. Towards tailoring the magnetocaloric response in FeRh-based ternary compounds

    Energy Technology Data Exchange (ETDEWEB)

    Barua, Radhika, E-mail: barua.r@husky.neu.edu; Jiménez-Villacorta, Félix; Lewis, L. H. [Department of Chemical Engineering, Northeastern University, Boston, Massachusetts 02115 (United States)

    2014-05-07

    In this work, we demonstrate that the magnetocaloric response of FeRh-based compounds may be tailored for potential magnetic refrigeration applications by chemical modification of the FeRh lattice. Alloys of composition Fe(Rh{sub 1−x}A{sub x}) or (Fe{sub 1−x}B{sub x})Rh (A = Cu, Pd; B = Ni; 0 < x < 0.06) were synthesized via arc-melting and subsequent annealing in vacuum at 1000 °C for 48 h. The magnetocaloric properties of the FeRh-based systems were determined using isothermal M(H) curves measured in the vicinity of the magnetostructural temperature (T{sub t}). It is found that the FeRh working temperature range (δT{sub FWHM}) may be chemically tuned over a wide temperature range, 100 K ≤ T ≤ 400 K. While elemental substitution consistently decreases the magnetic entropy change (ΔS{sub mag}) of the FeRh-based ternary alloys from that of the parent FeRh compound (ΔS{sub mag},{sub FeRh} ∼ 17 J/kg K; ΔS{sub mag,FeRh-ternary =} 7–14 J/kg K at H{sub app} = 2 T), the net refrigeration capacity (RC), defined as the amount of heat that can be transferred during one magnetic refrigeration cycle, of the modified systems is significantly higher (RC{sub FeRh} ∼ 150 J/kg; RC{sub FeRh-ternary =} 170–210 J/kg at H{sub app} = 2 T). These results are attributed to stoichiometry-induced changes in the FeRh electronic band structure and beneficial broadening of the magnetostructural transition due to local chemical disorder.

  10. Mechanical characterization and structural of Mg{sub 70}Zn{sub 28}Ca{sub 2} alloy for use as bioabsorbable implants; Caracterizacao mecanica e estrutural de uma liga Mg{sub 70}Zn{sub 28}Ca{sub 2} para uso como implante bioabsorvivel

    Energy Technology Data Exchange (ETDEWEB)

    Asato, G.H.; Matias, T.B.; Kiminami, C.S.; Botta, W.J.; Bolfarini, C., E-mail: asato.hitoshi@gmail.com [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil)

    2014-07-01

    A ternary magnesium-based alloy was studied for your biocompatibility, high mechanical properties, elastic modulus close to the bone and corrosion rate less than pure magnesium. The experimental conditions enabled to process a Mg70Zn28Ca2 ternary amorphous alloy by the fusion of eutectic binary alloys (Mg-Zn and Mg-Ca), which were obtained from pure elements in a induction furnace in an argon atmosphere. The characterization of alloy involved quantitative chemical analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The results indicated that the actual composition was very close to the nominal, with the presence of amorphous up to 1.3 mm thick. The mechanical compression test was performed in the conventional cylindrical samples with a diameter of 3 mm on an Instron type machine, obtaining the compressive strength above 400 MPa. (author)

  11. Spin glass-like behavior in spin-density-wave CrCoMn alloys

    Energy Technology Data Exchange (ETDEWEB)

    Galkin, Vladimir Yu. E-mail: galkin@magn.ru; Ortiz, Wilson A.; Ali, Naushad

    2003-03-01

    Magnetic susceptibility and magnetization of spin-density-wave (SDW) alloy systems (Cr+3.2%Co){sub 1-x}Mn{sub x} and (Cr+6.5%Co){sub 1-x}Mn{sub x} have been measured with a SQUID magnetometer. Magnetic properties of the studied alloys are compared with those exhibited by binary Cr{sub 1-x}Mn{sub x} and ternary (CrFe){sub 1-x}Mn{sub x} and (CrSi){sub 1-x}Mn{sub x} alloys. All these alloys show spin glass (SG)-like behavior; however, some of their magnetic properties are quite different from those exhibited by conventional metallic spin glasses. Though both Fe and Co produce a local moment in Cr and CrMn, addition of Co to CrMn does not result in suppression of SG-like phase like that in (CrFe){sub 1-x}Mn{sub x}. This seems to be a result of essentially different strengths of Fe-Cr and Co-Cr couplings. All alloys studied show a low-temperature SG-like magnetic hysteresis. Such hysteresis is shifted to negative fields by cooling the alloys in a strong magnetic field through the Neel temperature. This effect is caused by unidirectional anisotropy of Co atoms frozen in the SDW matrix.

  12. Metal-insulator transition of alloyed radical cation salts, (MexEDO-TTF)2PF6

    Science.gov (United States)

    Murata, Tsuyoshi; Shao, Xiangfeng; Nakano, Yoshiaki; Yamochi, Hideki; Saito, Gunzi; Uruichi, Mikio; Yakushi, Kyuya; Tanaka, Koichiro

    2010-06-01

    Ternary radical cation salts containing ethylenedioxytetrathiafulvalene, its mono-methyl substituted derivative, and hexafluorophosphate, [(EDO-TTF)1-x(MeEDO-TTF)x]2PF6 (x=mole fraction of MeEDO-TTF, x=0.01-0.13) were prepared by electrooxidation. Mole fractions of EDO-TTF and MeEDO-TTF in EDO-TTF rich alloys were consistent with the donor mixing ratios in preparation. Crystal structures of these alloys at room temperature were isostructural to that of (EDO-TTF)2PF6, where the donor molecules formed a nearly uniform stacking column to give a quasi-one-dimensional Fermi surface. The alloys exhibited a metal-insulator transition with tetramerization within the donor stack and anion-ordering. Temperature-variable structural analysis and Raman spectra revealed that the charge-ordering took place in the low temperature phase of x=0.05 alloy, however, this feature vanished in the x=0.13 alloy. The phase transition temperature decreased with increasing x value from 279 K of pristine (EDO-TTF)2PF6 to 188 K of x=0.13 alloy.

  13. Factoring with qutrits: Shor's algorithm on ternary and metaplectic quantum architectures

    Science.gov (United States)

    Bocharov, Alex; Roetteler, Martin; Svore, Krysta M.

    2017-07-01

    We determine the cost of performing Shor's algorithm for integer factorization on a ternary quantum computer, using two natural models of universal fault-tolerant computing: (i) a model based on magic state distillation that assumes the availability of the ternary Clifford gates, projective measurements, classical control as its natural instrumentation set; (ii) a model based on a metaplectic topological quantum computer (MTQC). A natural choice to implement Shor's algorithm on a ternary quantum computer is to translate the entire arithmetic into a ternary form. However, it is also possible to emulate the standard binary version of the algorithm by encoding each qubit in a three-level system. We compare the two approaches and analyze the complexity of implementing Shor's period-finding function in the two models. We also highlight the fact that the cost of achieving universality through magic states in MTQC architecture is asymptotically lower than in generic ternary case.

  14. High-performance ternary blend polymer solar cells involving both energy transfer and hole relay processes

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Luyao; Chen, Wei; Xu, Tao; Yu, Luping

    2015-06-04

    The integration of multiple materials with complementary absorptions into a singlejunction device is regarded as an efficient way to enhance the power conversion efficiency (PCE) of organic solar cells (OSCs). However, due to increased complexity with one more component, only limited high performance ternary systems have been demonstrated previously. Here, we report an efficient ternary blend OSC with a PCE of 9.2%. We show for the first time that the third component can reduce surface trap densities in the ternary blend. Detailed studies unravel that the improved performance results from synergistic effects of enlarged open circuit voltage, suppressed trap assisted recombination, enhanced light absorption, increased hole extraction, efficient energy transfer, and better morphology. The novel working mechanism and high device performance demonstrate new insights and design guidelines for high performance ternary blend solar cells and suggest that ternary structure is a promising platform to boost the efficiency of OSCs.

  15. Local Directional Ternary Pattern for Facial Expression Recognition.

    Science.gov (United States)

    Ryu, Byungyong; Rivera, Adin Ramirez; Kim, Jaemyun; Chae, Oksam

    2017-07-11

    This paper presents a new face descriptor, local directional ternary pattern (LDTP), for facial expression recognition. LDTP efficiently encodes information of emotion-related features (i.e., eyes, eyebrows, upper nose, and mouth) by using the directional information and ternary pattern in order to take advantage of the robustness of edge patterns in the edge region while overcoming weaknesses of edge-based methods in smooth regions. Our proposal, unlike existing histogram-based face description methods that divide the face into several regions and sample the codes uniformly, uses a two level grid to construct the face descriptor while sampling expression-related information at different scales. We use a coarse grid for stable codes (highly related to non-expression), and a finer one for active codes (highly related to expression). This multi-level approach enables us to do a finer grain description of facial motions, while still characterizing the coarse features of the expression. Moreover, we learn the active LDTP codes from the emotionrelated facial regions. We tested our method by using persondependent and independent cross-validation schemes to evaluate the performance. We show that our approaches improve the overall accuracy of facial expression recognition on six datasets.

  16. Genetic Synthesis of New Reversible/Quantum Ternary Comparator

    Directory of Open Access Journals (Sweden)

    DEIBUK, V.

    2015-08-01

    Full Text Available Methods of quantum/reversible logic synthesis are based on the use of the binary nature of quantum computing. However, multiple-valued logic is a promising choice for future quantum computer technology due to a number of advantages over binary circuits. In this paper we have developed a synthesis of ternary reversible circuits based on Muthukrishnan-Stroud gates using a genetic algorithm. The method of coding chromosome is presented, and well-grounded choice of algorithm parameters allowed obtaining better circuit schemes of one- and n-qutrit ternary comparators compared with other methods. These parameters are quantum cost of received reversible devices, delay time and number of constant input (ancilla lines. Proposed implementation of the genetic algorithm has led to reducing of the device delay time and the number of ancilla qutrits to 1 and 2n-1 for one- and n-qutrits full comparators, respectively. For designing of n-qutrit comparator we have introduced a complementary device which compares output functions of 1-qutrit comparators.

  17. Enhanced Light Absorption in Fluorinated Ternary Small-Molecule Photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Eastham, Nicholas D. [Department; Dudnik, Alexander S. [Department; Harutyunyan, Boris [Department; Aldrich, Thomas J. [Department; Leonardi, Matthew J. [Department; Manley, Eric F. [Department; Chemical; Butler, Melanie R. [Department; Harschneck, Tobias [Department; Ratner, Mark A. [Department; Chen, Lin X. [Department; Chemical; Bedzyk, Michael J. [Department; Department; Melkonyan, Ferdinand S. [Department; Facchetti, Antonio [Department; Chang, Robert P. H. [Department; Marks, Tobin J. [Department; Department

    2017-06-14

    Using small-molecule donor (SMD) semiconductors in organic photovoltaics (OPVs) has historically afforded lower power conversion efficiencies (PCEs) than their polymeric counterparts. The PCE difference is attributed to shorter conjugated backbones, resulting in reduced intermolecular interactions. Here, a new pair of SMDs is synthesized based on the diketopyrrolopyrrole-benzodithiophene-diketopyrrolopyrrole (BDT-DPP2) skeleton but having fluorinated and fluorinefree aromatic side-chain substituents. Ternary OPVs having varied ratios of the two SMDs with PC61BM as the acceptor exhibit tunable open-circuit voltages (Vocs) between 0.833 and 0.944 V due to a fluorination-induced shift in energy levels and the electronic “alloy” formed from the miscibility of the two SMDs. A 15% increase in PCE is observed at the optimal ternary SMD ratio, with the short-circuit current density (Jsc) significantly increased to 9.18 mA/cm2. The origin of Jsc enhancement is analyzed via charge generation, transport, and diffuse reflectance measurements, and is attributed to increased optical absorption arising from a maximum in film crystallinity at this SMD ratio, observed by grazing incidence wide-angle X-ray scattering.

  18. Phase transformations in a manganese-alloyed austenitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Jargelius-Pettersson, R.F.A. (Swedish Inst. for Metals Research, Stockholm (Sweden))

    1994-05-01

    The increasing demands placed on the corrosion resistance of stainless steels has led to the successive development of more highly alloyed materials. In this context nitrogen has shown considerable value as an alloying element but its use is restricted by a solubility limit of approximately 0.2 wt% in conventional austenitic stainless steel grades. Manganese increases the nitrogen solubility appreciably and for this reason there has also been an increased interest in its use as an alloying addition but numerous questions remain to be answered about the effect of both nitrogen and manganese on structural stability. Although much work has been published on the precipitation of secondary phases in CrNi(Mo) stainless steels, there is a relative paucity of information available on manganese-alloyed steels. Brandis et al. investigated precipitation in a 25Cr 17Ni 3Mo 6Mn 0.2Nb steel and found no manganese-enriched phases to occur. Sigma phase was the predominant intermetallic precipitate at low nitrogen contents while higher nitrogen contents retarded the onset of sigma phase precipitation but caused the appearance of chi phase. Boothby et al. investigated a 12Cr 11-35Ni (3Mo) steel in which the nickel was partially replaced by 20 or 30% manganese and found the precipitation of the intermetallic sigma, chi and Laves phases to be promoted by manganese, although again no manganese-enriched phases were observed. Fritscher demonstrated however the existence in the Fe-Cr-Ni system of a brittle ternary Y phase containing 30--60% manganese which was destabilized by nitrogen. The present work represents part of a study designed to gain greater understanding of the precipitation and sensitization behavior of highly alloyed austenitic stainless steels and concentrates on the influence of nitrogen additions up to 0.5wt% on precipitation of secondary phases in a 20Cr 18Ni 4.5Mo 10Mn steel.

  19. Engineering Platinum Alloy Electrocatalysts in Nanoscale for PEMFC Application

    Energy Technology Data Exchange (ETDEWEB)

    He, Ting [Idaho National Laboratory

    2016-03-01

    particle size and microcomposition in nanoscale, it is able to achieve superior electrocatalytic activities comparing with traditional preparative methods. Examples to be discussed are high surface area carbon supported Pt, PtM binary, and PtMN ternary alloys, their synthesis processes, characterizations and electrocatalytic activities towards molecular oxygen reduction.

  20. KTP laser stapedotomy with a self-crimping, thermal shape memory Nitinol piston: follow-up study reporting intermediate-term hearing.

    Science.gov (United States)

    Gerlinger, Imre; Bakó, Péter; Piski, Zalán; Révész, Péter; Ráth, Gábor; Karosi, Tamás; Lujber, László

    2014-12-01

    The aim of this study was an evaluation of the mid-term hearing results after the implantation of a self-crimping heat memory Nitinol piston in stapes surgery. The 12-month postoperative results were compared with those at a minimum of 3 years (maximum 6.7, average 4.4 years). The medical records of all 44 patients who underwent surgery with a Nitinol piston for stapes fixation between November 2005 and January 2007 were evaluated retrospectively. The prostheses used in all cases measured either 4.5 or 4.75 × 0.6 mm. We hypothesized that the 12-month postoperative hearing results would be permanent after an average follow-up of 4.4 years. Thirty-two of the 44 consecutive patients were females and 12 were males. Their mean age was 40.4 years (range 27-69). All underwent a 12-month postoperative audiometric evaluation. 38 (30 females, 8 males, average age 45, range 28-77 years) of the 44 were available for mid-term 4.4-year (minimum 3 years, maximum 6.7 years) postoperative audiometric evaluation. The mean air-bone gap (ABG) for the frequencies 0.5, 1, 2 and 3 kHz at the 12-month postoperative follow-up was 11 dB (SD 4.1) and that after an average 4.4-year postoperative evaluation was 6.4 dB (SD 3.6). The mean decrease in ABG after 12 months was 19.5 dB, and that after the average 4.4 years was 21.3 dB. ABG closure within 10 dB was achieved in 77.2 % after 12 months and in 89.5 % after the average 4.4 years. No patient with an ABG > 20 dB was recorded after the average 4.4 years. The mean air conduction threshold at 4 kHz was examined pre and postoperatively so as to indicate any possible inner ear damage. At the 12-month follow-up, the difference between the pre and postoperative values was -2.5 dB, whereas after the average 4.4 years the difference was surprisingly +13 dB. The individual AC improvements were also demonstrated with the use of Amsterdam Hearing Evaluation Plots (AHEPs). The Nitinol prosthesis allowed excellent intraoperative handling and no