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Sample records for additive al oh3

  1. Synthesis and characterization of non halogen fire retardant composite through combination of epoxy resin, Al(OH)3 additive and filler

    Science.gov (United States)

    Saputra, Asep Handaya; Sungkar, Faraj

    2017-11-01

    Epoxy has a wide range of applications in many sectors, but it still has deficiency in fire retardancy. Therefore, it is combined with fire retardant additives. Fire retardant additive commonly contains halogen compounds that causes environmental and health problems. Therefore Al (OH)3 additive is used to improve the fire retardancy properties of composite through decomposition that produced water vapour and formation of oxide layer on its surface. In this research, synthesis of fire retardant composite has been conducted by varying filler carbon black and silica (1%, 2.5%, 5%, 7.5%, 10%wt) with composition of Al (OH)3 50%wt and epoxy 50%wt. Fire retardancy of composite was observed by UL-94V standard, while thermal degradation behaviour of composite was analyzed by thermal gravimetric analysis and differential scanning calorimetry. Whereas, mechanical properties was studied based on its tensile strength and hardness. It was found that the best concentration for carbon black and silica is 1%wt and 2.5%wt respectively. The addition of carbon black 1%wt and silica 2.5%wt could improve the flame retardancy and gives V-0 flammability rating. Besides that, the addition of carbon black 1%wt is able to increase the thermal stability of composite by reducing mass loss rate until 10.75%/minute and total mass loss until 53.76%. While adding silica 2.5%wt could also enhance its thermal stability by decreasing mass loss rate until 9.32%/minute and total mass loss until 51.06%. Furthermore, the addition of carbon black and silica could decrease its tensile strength and hardness. The addition of carbon black 1%wt yields composite with 6.59 MPa for tensile strength and 65.8 shore D for hardness. Whereas the addition of of silica 2.5%wt produces composite with the tensile strength up to 9.89MPa and hardness up to71.2 shore D.

  2. Synthesis of Al(OH3 Nanostructures from Al(OH3 Microagglomerates via Dissolution-Precipitation Route

    Directory of Open Access Journals (Sweden)

    Bo Yu

    2013-01-01

    Full Text Available A facile method was developed to synthesize Al(OH3 nanostructures from Al(OH3 microagglomerates by dissolution in 9.0 mol·L−1 NaOH at 115°C followed by dilution and aging of the solution at room temperature. The influence of Al(OH3 nanoseed and surfactants as sodium dodecyl sulfate (SDS, polyethylene glycol 6000 (PEG6000, and cetyltrimethylammonium bromide (CTAB on the formation of the Al(OH3 nano-structures was investigated. The experimental results indicated that the Al(OH3 microspheres composed of nanoparticles were prepared in the blank experiment, while dispersive Al(OH3 nano-particles with a diameter of 80–100 nm were produced in the presence of Al(OH3 nano-seed and CTAB.

  3. New insights into the intercalation chemistry of Al(OH)3.

    Science.gov (United States)

    Williams, Gareth R; Moorhouse, Saul J; Prior, Timothy J; Fogg, Andrew M; Rees, Nicholas H; O'Hare, Dermot

    2011-06-14

    This paper reports a number of recent developments in the intercalation chemistry of Al(OH)(3). From Rietveld refinement and solid-state NMR, it has been possible to develop a structural model for the recently reported [M(II)Al(4)(OH)(12)](NO(3))(2)·yH(2)O family of layered double hydroxides (LDHs). The M(2+) cations occupy half of the octahedral holes in the Al(OH)(3) layers, and it is thought that there is complete ordering of the metal ions while the interlayer nitrate anions are highly disordered. Filling the remainder of the octahedral holes in the layers proved impossible. While the intercalation of Li salts into Al(OH)(3) is facile, it was found that the intercalation of M(II) salts is much more capricious. Only with Co, Ni, Cu, and Zn nitrates and Zn sulfate were phase-pure LDHs produced. In other cases, there is either no reaction or a phase believed to be an LDH forms concomitantly with impurity phases. Reacting Al(OH)(3) with mixtures of M(II) salts can lead to the production of three-metal M(II)-M(II)'-Al LDHs, but it is necessary to control precisely the starting ratios of the two M(II) salts in the reaction gel because Al(OH)(3) displays selective intercalation of M nitrate (Li > Ni > Co ≈ Zn). The three-metal M(II)-M(II)'-Al LDHs exhibit facile ion exchange intercalation, which has been investigated in the first energy dispersive X-ray diffraction study of a chemical reaction system performed on Beamline I12 of the Diamond Light Source.

  4. Facile synthesis of Co(OH)2/Al(OH)3 nanosheets with improved electrochemical properties for asymmetric supercapacitor

    Science.gov (United States)

    Zhao, Cuimei; Ren, Fang; Cao, Yang; Xue, Xiangxin; Duan, Xiaoyue; Wang, Hairui; Chang, Limin

    2018-01-01

    Sheet-like Co(OH)2/Al(OH)3 or Co(OH)2 nanomaterial has been synthesized on conducting carbon fiber paper (CFP) by a facile one-step electrochemical deposition. The binder-free Co(OH)2/Al(OH)3/CFP displays an improved electrical conductivity, electrochemical activity and material utilization than solitary Co(OH)2, therefore Co(OH)2/Al(OH)3 nanomaterial exhibits improved electrochemical properties (a maximum capacitance of 1006 Fg-1 at 2 Ag-1, with 77% retention even at a high current density of 32 Ag-1, and more than 87% of the capacitance retention after 10000 cycles at 32 Ag-1) in comparison to that of the Co(OH)2/CFP (709 Fg-1, 65%, 79%). In addition, an asymmetric supercapacitor (ASC) fabricated with Co(OH)2/Al(OH)3/CFP positive electrode and AC/CFP negative electrode demonstrates ultrahigh specific capacitance (75.8 Fg-1) and potential window (1.7 V). These encouraging results make these low-cost and eco-friendly materials promising for high-performance energy storage application.

  5. Preparation, optical properties of ZnO, ZnO:Al nanorods and Y(OH)3:Eu nanotube

    International Nuclear Information System (INIS)

    Tran Kim Anh; Dinh Xuan Loc; Lam thi Kieu Giang; Le Quoc Minh; Strek, Wieslaw

    2009-01-01

    ZnO, ZnO:Al nanorods and Y(OH) 3 nanotubes have been prepared by the chemical vapor deposition and liquid phase synthesis. ZnO nanorods with diameter of 50 - 100 nm and length of 5 μm have been obtained by the CVD method. ZnO:Al nanorods were synthesized by the hydrothermal method from ZnSO 4. and Al 2 (SO 4 ) 3 . Nanorods and nanotubes of Y(OH) 3 with diameter of 200 nm and length of several micrometers were prepared by the soft template method. The crystal structure and morphology of rods and tubes were analyzed by the X-Ray diffraction and FE-SEM. The influence of fabrication conditions and Al, Eu concentration have been discussed.

  6. Reaction mechanisms of phosphate with Al(OH)3 and a sandy soil

    NARCIS (Netherlands)

    Riemsdijk, van W.H.

    1979-01-01

    Al(OH) 3 is a very effective sorbent for orthophosphate especially at low pH. At low phosphate concentration c p , phosphate is adsorbed by an exchange mechanism with singly coordinated OH(H) groups residing on the surface of the Al(OH)

  7. Laboratory study on the adsorption of Mn(2+) on suspended and deposited amorphous Al(OH)(3) in drinking water distribution systems.

    Science.gov (United States)

    Wang, Wendong; Zhang, Xiaoni; Wang, Hongping; Wang, Xiaochang; Zhou, Lichuan; Liu, Rui; Liang, Yuting

    2012-09-01

    Manganese (II) is commonly present in drinking water. This paper mainly focuses on the adsorption of manganese on suspended and deposited amorphous Al(OH)(3) solids. The effects of water flow rate and water quality parameters, including solution pH and the concentrations of Mn(2+), humic acid, and co-existing cations on adsorption were investigated. It was found that chemical adsorption mainly took place in drinking water with pHs above 7.5; suspended Al(OH)(3) showed strong adsorption capacity for Mn(2+). When the total Mn(2+) input was 3 mg/L, 1.0 g solid could accumulate approximately 24.0 mg of Mn(2+) at 15 °C. In drinking water with pHs below 7.5, because of H(+) inhibition, active reaction sites on amorphous Al(OH)(3) surface were much less. The adsorption of Mn(2+) on Al(OH)(3) changed gradually from chemical coordination to physical adsorption. In drinking water with high concentrations of Ca(2+), Mg(2+), Fe(3+), and HA, the removal of Mn(2+) was enhanced due to the effects of co-precipitation and adsorption. In solution with 1.0 mg/L HA, the residual concentration of Mn(2+) was below 0.005 mg/L, much lower than the limit value required by the Chinese Standard for Drinking Water Quality. Unlike suspended Al(OH)(3), deposited Al(OH)(3) had a much lower adsorption capacity of 0.85 mg/g, and the variation in flow rate and major water quality parameters had little effect on it. Improved managements of water age, pipe flushing and mechanical cleaning were suggested to control residual Mn(2+). Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Statistical Evaluation of Potential Damage to the Al(OH)3 Layer on nTiO2 Particles in the Presence of Swimming Pool and Seawater

    Science.gov (United States)

    Nanosized TiO2 particles (nTiO2) are usually coated with an Al(OH)3 layer when used in sunscreen to shield against the harmful effects of free radicals that are generated when these particles are exposed to UV radiation. Therefore, it is vital to ...

  9. 1 IN TR ODU CT ION Gibbsite (7-Al(OH)3) and boehmite (7-AlOOH ...

    African Journals Online (AJOL)

    2005-07-10

    Jul 10, 2005 ... of A-B-B-A-A-B-B-A-A-B in the direction perpen- dicular to the planes. On dehydroxylation, boehmite and gibbsite do not go directly to the thermodynamically stable a-. Al2O3 phase. Initially the long range crystalline order is destroyed to give 'transition aluminas' or. 'activated aluminas' (Misra, 1 986, Ingram ...

  10. A simple method to prepare ZnO and Al(OH)3 nanorods by the reaction of the metals with liquid water

    International Nuclear Information System (INIS)

    Panchakarla, L.S.; Shah, M.A.; Govindaraj, A.; Rao, C.N.R.

    2007-01-01

    Reaction of liquid water with Zn and Al powders and foils have been investigated in the 25-75 deg. C range. The reaction of Zn metal powder with water in this temperature range yields ZnO nanorods. The diameter of the nanorods decreases slightly with the increase in the reaction temperature, accompanied by an increase in the relative intensity of UV emission band. Zn metal foils also yield ZnO nanorods on reaction with water in the 25-75 deg. C range. Reaction of Al metal powder or foil with water in the 25-75 deg. C range yields Al(OH) 3 nanorods. The formation of ZnO and Al(OH) 3 nanorods by the reaction of the metals with water is suggested to occur because of the decomposition of water by the metal giving hydrogen. - Graphical abstract: The reaction of water at a temperature in the 25-27 deg. C range with zinc metal gives rise to ZnO nanorods; with Al metal water gives Al(OH) 3 nanorods

  11. Elasticity of phase-Pi (Al3Si2O7(OH)3) - A hydrous aluminosilicate phase

    Science.gov (United States)

    Peng, Ye; Mookherjee, Mainak; Hermann, Andreas; Bajgain, Suraj; Liu, Songlin; Wunder, Bernd

    2017-08-01

    Phase-Pi (Al3Si2O7(OH)3) is an aluminosilicate hydrous mineral and is likely to be stable in hydrated sedimentary layers of subducting slabs. Phase-Pi is likely to be stable between the depths of 60 and 200 km and is likely to transport water into the Earth's interior. Here, we use first principles simulations based on density functional theory to explore the crystal structure at high-pressure, equation of state, and full elastic stiffness tensor as a function of pressure. We find that the pressure volume results could be described by a finite strain fit with V0 , K0 , and K0‧ being 310.3 Å3, 133 GPa, and 3.6 respectively. At zero pressure, the full elastic stiffness tensor shows significant anisotropy with the diagonal principal components C11 , C22 , and C33 being 235, 292, 266 GPa respectively, the diagonal shear C44 , C55 , and C66 being 86, 92, and 87 GPa respectively, and the off-diagonal stiffness C12 , C13 , C14 ,C15 , C16 , C23 , C24 , C25 , C26 , C34 , C35 , C36 , C45 , C46 , and C56 being 73, 78, 6, -30, 15, 61, 17, 2, 1, -13, -15, 6, 3, 1, and 3 GPa respectively. The zero pressure, shear modulus, G0 and its pressure derivative, G0 ‧ are 90 GPa and 1.9 respectively. Upon compression, hydrogen bonding in phase-Pi shows distinct behavior, with some hydrogen bonds weakening and others strengthening. The latter eventually undergo symmetrization, at pressure greater (>40 GPa) than the thermodynamic stability of phase-Pi. Full elastic constant tensors indicate that phase-Pi is very anisotropic with AVP ∼22.4% and AVS ∼23.7% at 0 GPa. Our results also indicate that the bulk sound velocity of phase-Pi is slower than that of the high-pressure hydrous aluminosilicate phase, topaz-OH.

  12. Statistical evaluation of potential damage to the Al(OH)3 layer on nTiO2 particles in the presence of swimming pool and seawater

    International Nuclear Information System (INIS)

    Virkutyte, Jurate; Al-Abed, Souhail R.

    2012-01-01

    Nanosized TiO 2 particles (nTiO 2 ) are usually coated with an Al(OH) 3 layer when used in sunscreen to shield against the harmful effects of free radicals that are generated when these particles are exposed to UV radiation. Therefore, it is vital to insure the structural stability of these particles in the environment where the protective layer may be damaged and adverse health and environmental effects can occur. This study utilized X-ray analysis (SEM–EDS) to provide a qualitative and semi-quantitative assessment of the chemical and physical characteristics of Al(OH) 3 -coated original and damaged nTiO 2 particles (used in sunscreen lotion formulations) in the presence of both swimming pool and seawater. Also, by utilizing statistical tools, a distribution of Al/Ti (%) on the particle surface was determined and evaluated. It was found that 45 min of treatment with swimming pool and seawater significantly induced the redistribution of Al/Ti (%), which changed the surface characteristics of particles and, therefore, may have induced undesired photo-activity and the consequent formation of free radicals.

  13. Properties of B4C–PbO–Al(OH)3-epoxy nanocomposite prepared by ultrasonic dispersion approach for high temperature neutron shields

    International Nuclear Information System (INIS)

    Lee, M.K.; Lee, J.K.; Kim, J.W.; Lee, G.J.

    2014-01-01

    High functional epoxy nanocomposites with three different filler materials, i.e., B 4 C, PbO, and Al(OH) 3 , were fabricated using an effective fabrication method consisting of an ultrasonic dispersion of nanoparticles in low-viscosity hardener and a subsequent mixing of a hardener-nanoparticle colloid with epoxy resins. It was confirmed that this approach provided not only an uniform dispersion but also an excellent wetting with enhanced interfacial adhesion of nano-particulate fillers within the matrix. By incorporating those three fillers, a synergistic effect was verified in multiple properties such as mechanical strength properties, thermal degradation, flame retardancy, and radiation shielding performance

  14. Thermoluminescent properties of polycrystalline carbon doped LaAlO3/La(OH)3 crystals synthesized by solid state reaction for application in UV dosimetry

    International Nuclear Information System (INIS)

    Alves, N.; Oliveira de F, L.; Barbosa F, W.

    2017-10-01

    It is well known that UV radiation can induce certain deleterious effects, such as erythema, painful inflammation of the membrane of the eye and skin cancer. Therefore, it has been pushing the research for producing new and high performance UV sensitive Tl materials. There is an increasing interest in the development of new Tl materials for ultraviolet (UV) dosimetry purposes, owing to simplicity of the sample readout compared to other techniques. In this paper, thermoluminescence and dosimetric characteristics of pure and carbon doped lanthanum aluminate and hydroxide lanthanum crystals, irradiated with different UV doses, were studied and discussed. All samples studied were produced by solid state reaction method with different mixing methodologies. Characterization of sintered powders by X-ray diffraction, UV-Vis spectrophotometry and Ftir spectroscopy were performed. XRD data confirmed the LaAlO 3 and La(OH) 3 crystalline phases. The thermoluminescent study revealed that all compositions presented high UV sensibility. The sample which was grown by first sintering La 2 O 3 together carbon atoms and then sintering again in order to obtain La 2 O 3 :C together Al 2 O 3 , presented the best linear dose response over UV doses ranging from 0.042 to 0.63 mJ/cm 2 , with correlation coefficients equal to 0.99931. The synthesis methodology used was very efficient to obtain crystals with high Tl output intensities for low exposure rate UV R fields. (Author)

  15. Experimental cation redistribution in the tourmaline lucchesiite, CaFe2 + 3Al6(Si6O18)(BO3)3(OH)3O

    Science.gov (United States)

    Bosi, Ferdinando; Skogby, Henrik; Hålenius, Ulf; Ciriotti, Marco E.

    2018-02-01

    Natural Mg-rich lucchesiite was thermally treated in air and hydrogen atmosphere up to 800 °C to study potential changes in Fe-, Mg- and Al ordering over the octahedrally coordinated Y- and Z-sites, and to explore possible applications to intracrystalline geothermometry based on tourmaline. Overall, the experimental data (structural refinement, Mössbauer, infrared and optical absorption spectroscopy) show that thermal treatment of lucchesiite results in an increase of Fetot contents at Z balanced by an increase of Mg and Al at Y. This process is accompanied by a significant deprotonation of the O3 anion site. The Fe order-disorder reaction depends more on temperature, than on redox conditions. During heat treatment in H2, reduction of Fe3+ to Fe2+ was not observed despite strongly reducing conditions, indicating that the f O2 conditions do not exclusively control the Fe oxidation state at the present experimental conditions. On the basis of this and previous studies, the intersite order-disorder process induced by thermal treatment indicates that Fe redistribution is an important factor for Fe-Mg-Al-exchange and is significant at temperatures around 800 °C. As a result, Fe-Mg-Al intersite order-disorder is sensitive to temperature variations, whereas geothermometers based solely on Mg-Al order-disorder appear insensitive and involve large uncertainties. The presented findings are important for interpretation of the post-crystallization history of both tourmaline and tourmaline host rocks, and indicate that successful tourmaline geothermometers may be developed by thermal calibration of the Fe-Mg-Al order-disorder reaction.

  16. Formation and characterization of nanotubes of La(OH)3 obtained using porous alumina membranes

    International Nuclear Information System (INIS)

    Gonzalez-Rovira, L; Sanchez-Amaya, J M; Botana, F J; Lopez-Haro, M; Hungria, A B; Boukha, Z; Bernal, S

    2008-01-01

    An electrodeposition process is used to synthesize nanotubes of a lanthanum-containing phase, employing porous alumina membranes as templates. This method should lead to the formation of La(OH) 3 nanowires, according to the previous results presented by Bocchetta et al (2007 Electrochem. Commun. 9 683-8), which can be decomposed to La 2 O 3 , as the latter shows more interest for different applications. The results obtained by means of different electron microscopy techniques indicate that this method leads to the formation of nanotubes of about 200 nm in diameter and 30-40 μm in length, instead of the nanowires proposed in the literature. Additionally, the chemical characterization demonstrates that the material synthesized is composed of lanthanum hydroxycarbonate. The presence of carbonates is found to be crucial in determining the conditions for the preparation of La 2 O 3 from the nanotubes here obtained.

  17. Formation and characterization of nanotubes of La(OH)3 obtained using porous alumina membranes

    Science.gov (United States)

    González-Rovira, L.; Sánchez-Amaya, J. M.; López-Haro, M.; Hungria, A. B.; Boukha, Z.; Bernal, S.; Botana, F. J.

    2008-12-01

    An electrodeposition process is used to synthesize nanotubes of a lanthanum-containing phase, employing porous alumina membranes as templates. This method should lead to the formation of La(OH)3 nanowires, according to the previous results presented by Bocchetta et al (2007 Electrochem. Commun. 9 683-8), which can be decomposed to La2O3, as the latter shows more interest for different applications. The results obtained by means of different electron microscopy techniques indicate that this method leads to the formation of nanotubes of about 200 nm in diameter and 30-40 µm in length, instead of the nanowires proposed in the literature. Additionally, the chemical characterization demonstrates that the material synthesized is composed of lanthanum hydroxycarbonate. The presence of carbonates is found to be crucial in determining the conditions for the preparation of La2O3 from the nanotubes here obtained.

  18. Nitrate-assisted photocatalytic efficiency of defective Eu-doped Pr(OH)3 nanostructures.

    Science.gov (United States)

    Aškrabić, S; Araújo, V D; Passacantando, M; Bernardi, M I B; Tomić, N; Dojčinović, B; Manojlović, D; Čalija, B; Miletić, M; Dohčević-Mitrović, Z D

    2017-12-06

    Pr(OH) 3 one-dimensional nanostructures are a less studied member of lanthanide hydroxide nanostructures, which recently demonstrated an excellent adsorption capacity for organic pollutant removal from wastewater. In this study, Pr 1-x Eu x (OH) 3 (x = 0, 0.01, 0.03, and 0.05) defective nanostructures were synthesized by a facile and scalable microwave-assisted hydrothermal method using KOH as an alkaline metal precursor. The phase and surface composition, morphology, vibrational, electronic and optical properties of the as-prepared samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma optical emission spectrometry (ICP-OES), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), Raman, infrared (IR), photoluminescence (PL), and diffuse reflectance spectroscopy (DRS). It was deduced that the incorporation of Eu 3+ ions promoted the formation of oxygen vacancies in the already defective Pr(OH) 3 , subsequently changing the Pr(OH) 3 nanorod morphology. The presence of KNO 3 phase was registered in the Eu-doped samples. The oxygen-deficient Eu-doped Pr(OH) 3 nanostructures displayed an improved photocatalytic activity in the removal of reactive orange (RO16) dye under UV-vis light irradiation. An enhanced photocatalytic activity of the Eu-doped Pr(OH) 3 nanostructures was caused by the synergetic effect of oxygen vacancies and Eu 3+ (NO 3 - ) ions present on the Pr(OH) 3 surface, the charge separation efficiency and the formation of the reactive radicals. In addition, the 3% Eu-doped sample exhibited very good adsorptive properties due to different morphology and higher electrostatic attraction with the anionic dye. Pr 1-x Eu x (OH) 3 nanostructures with the possibility of tuning their adsorption/photocatalytic properties present a great potential for wastewater treatment.

  19. Formation of AlFeSi phase in AlSi12 alloy with Ce addition

    Directory of Open Access Journals (Sweden)

    S. Kores

    2012-04-01

    Full Text Available The influence of cerium addition on the solidification sequence and microstructure constituents of the Al-Si alloys with 12,6 mass % Si was examined. The solidification was analyzed by a simple thermal analysis. The microstructures were examined with conventional light and scanning electron microscopy. Ternary AlSiCe phase was formed in the Al-Si alloys with added cerium during the solidification process. AlSiCe and β-AlFeSi phases solidified together in the region that solidified the last. Cerium addition influenced on the morphology of the α-AlFeSi phase solidification.

  20. Microstructure and mechanical properties of molybdenum silicides with Al additions

    International Nuclear Information System (INIS)

    Rosales, I.; Bahena, D.; Colin, J.

    2007-01-01

    Several molybdenum silicides alloys with different aluminum additions were produced by the arc-cast method. Microstructure observed in the alloys presented a variation of the precipitated second phase respect to the aluminum content. Evaluation of the compressive behavior at high temperature of the alloys shows an important improvement in its ductility, approximately of 20%. Fracture toughness was increased proportionally with Al content. In addition at room temperature the alloys show a better mechanical behavior in comparison with the sample unalloyed. In general, Al additions result to be a good alternative to improve the resistance of these intermetallic alloys. The results are interpreted on the base of the analysis of second phase strengthening

  1. Fracture toughness of Al-Cr alloys with minor additions

    International Nuclear Information System (INIS)

    Datta, S.; Banerjee, M.K.

    2000-01-01

    Fracture toughness behavior of aluminium chromium alloys with minor additions is studied to determine its relation with microstructure and ageing conditions. The effect of the minor additions on the fracture toughness property of the alloys is also studied. Fracture toughness of Al-Cr alloys has been improved by selected minor additions. Also, the fracture toughness of the investigated alloys is found to be sensitive to ageing conditions. (author)

  2. Ultrasonic assessment of additive manufactured Ti-6Al-4V

    Science.gov (United States)

    Schehl, Norman; Kramb, Vicki; Dierken, Josiah; Aldrin, John; Schwalbach, Edwin; John, Reji

    2018-04-01

    Additive Manufacturing (AM) processes offer the potential for manufacturing cost savings and rapid insertion into service through production of near net shape components for complicated structures. Use of these parts in high reliability applications such as those in the aerospace industry will require nondestructive characterization methods to ensure post-process material quality in as-built condition. Ultrasonic methods can be used for this quality verification. Depending on the application, the service life of AM components can be sensitive to the part surface condition. The surface roughness and layered structure inherent to the electron-beam powder-bed fusion process necessitates new approaches to evaluate subsurface material integrity in its presence. Experimental methods and data analytics may improve the evaluation of as-built additively manufactured materials. This paper discusses the assessment of additively manufactured EBM Ti-6Al-4V panels using ultrasonic methods and the data analytics applied to evaluate material integrity. The assessment was done as an exploratory study as the discontinuities of interest in these test samples were not known when the measurements were performed. Water immersion ultrasonic techniques, including pulse-echo and through transmission with 10 MHz focused transducers, were used to explore the material integrity of as-built plates. Subsequent destructive mechanical tests of specimens extracted from the plates provided fracture locations indicating critical flaws. To further understand the effect of surface-roughness, an evaluation of ultrasonic response in the presence of as-built surfaces and with the surface removed was performed. The assessment of additive manufactured EBM Ti-6Al-4V panels with ultrasonic techniques indicated that ultrasonic energy was attenuated by the as-built surface roughness. In addition, feature detection was shown to be sensitive to experimental ultrasonic parameters and flaw morphology.

  3. Fabrication and properties of highly luminescent materials from Tb(OH)3-SiO2 and Tb(OH)3-SiO2:Eu3+ nanotubes

    International Nuclear Information System (INIS)

    Tran Thu Huong; Tran Kim Anh; Le Quoc Minh

    2009-01-01

    Luminescent nanomaterials with one-dimensional (1D) structures have attracted much attention due to their unique properties and potential applications in nanophotonics and nanobiophotonics. In this paper, we report a synthesis of terbium - hydroxide - at - silica Tb(OH) 3 -SiO 2 and Tb(OH) 3 -SiO 2 :Eu 3+ nanotubes. Terbium - hydroxide tubes were synthesized by soft template method. The size of the tubes can be controlled precisely and have outer diameters ranging from 80 to 120 nm, wall thickness of about 30 nm, and lengths ranging from 300 to 800 nm. To fabricate core/shell materials, the seed growth method is used. FESEM, X-ray diffraction, Raman spectra of Tb(OH) 3 and Tb(OH) 3 -SiO 2 nanotubes were investigated. The photoluminescence (PL) spectrum of Tb(OH) 3 under 325 nm excitation consists of four main peaks at 488, 542, 582, and 618 nm. Furthermore, a preliminary suggestion for the mechanism of growth of the Tb(OH) 3 nanotubes using the soft - template synthesis technique has been proposed. The PL intensity from Tb(OH) 3 -SiO 2 or Tb(OH) 3 -SiO 2 :Eu 3+ nanotubes is much stronger than that of Tb(OH) 3 .

  4. Grain refining mechanism of Al-containing Mg alloys with the addition of Mn-Al alloys

    International Nuclear Information System (INIS)

    Qin, Gaowu W.; Ren Yuping; Huang Wei; Li Song; Pei Wenli

    2010-01-01

    Graphical abstract: Display Omitted Research highlights: The ε-AlMn phase acts as the heterogeneous nucleus of α-Mg phase during the solidification of the AZ31 Mg alloy, not the γ-Al 8 Mn 5 phase. The grain refinement effect is very clear with the addition of only 0.5 wt% Mn-28Al alloy (pure ε-AlMn). The grain refinement does not deteriorate up to the holding time of 60 min at 740 o C. - Abstract: The effect of manganese on grain refinement of Al-containing AZ31 Mg alloy has been investigated by designing a series of Mn-Al alloys composed of either pure ε-AlMn, γ 2 -Al 8 Mn 5 or both of them using optical microscopy and X-ray diffraction. It is experimentally clarified that the grain refinement of the AZ31 Mg alloy is due to the existence of the ε-AlMn phase in the Mn-Al alloys, not the γ 2 -Al 8 Mn 5 phase. The grain size of AZ31 Mg alloy is about 91 μm without any addition of Mn-Al alloys, but remarkably decreases to ∼55 μm with the addition of either Mn-34 wt% Al or Mn-28 wt% Al. With a minor addition of 0.5 wt% Mn-28Al alloy, the grain size of AZ31 alloy decreases to ∼53 μm, and the Mn-28Al alloy can be active as grain refiner for holding time up to 60 min for the melt AZ31 alloy at 750 o C.

  5. Grain refining mechanism of Al-containing Mg alloys with the addition of Mn-Al alloys

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Gaowu W., E-mail: qingw@smm.neu.edu.c [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Wenhu Road 3-11, Heping District, Shenyang 110004, Liaoning Province (China); Ren Yuping; Huang Wei; Li Song; Pei Wenli [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Wenhu Road 3-11, Heping District, Shenyang 110004, Liaoning Province (China)

    2010-10-08

    Graphical abstract: Display Omitted Research highlights: The {epsilon}-AlMn phase acts as the heterogeneous nucleus of {alpha}-Mg phase during the solidification of the AZ31 Mg alloy, not the {gamma}-Al{sub 8}Mn{sub 5} phase. The grain refinement effect is very clear with the addition of only 0.5 wt% Mn-28Al alloy (pure {epsilon}-AlMn). The grain refinement does not deteriorate up to the holding time of 60 min at 740 {sup o}C. - Abstract: The effect of manganese on grain refinement of Al-containing AZ31 Mg alloy has been investigated by designing a series of Mn-Al alloys composed of either pure {epsilon}-AlMn, {gamma}{sub 2}-Al{sub 8}Mn{sub 5} or both of them using optical microscopy and X-ray diffraction. It is experimentally clarified that the grain refinement of the AZ31 Mg alloy is due to the existence of the {epsilon}-AlMn phase in the Mn-Al alloys, not the {gamma}{sub 2}-Al{sub 8}Mn{sub 5} phase. The grain size of AZ31 Mg alloy is about 91 {mu}m without any addition of Mn-Al alloys, but remarkably decreases to {approx}55 {mu}m with the addition of either Mn-34 wt% Al or Mn-28 wt% Al. With a minor addition of 0.5 wt% Mn-28Al alloy, the grain size of AZ31 alloy decreases to {approx}53 {mu}m, and the Mn-28Al alloy can be active as grain refiner for holding time up to 60 min for the melt AZ31 alloy at 750 {sup o}C.

  6. Machinability of Al 6061 Deposited with Cold Spray Additive Manufacturing

    Science.gov (United States)

    Aldwell, Barry; Kelly, Elaine; Wall, Ronan; Amaldi, Andrea; O'Donnell, Garret E.; Lupoi, Rocco

    2017-10-01

    Additive manufacturing techniques such as cold spray are translating from research laboratories into more mainstream high-end production systems. Similar to many additive processes, finishing still depends on removal processes. This research presents the results from investigations into aspects of the machinability of aluminum 6061 tubes manufactured with cold spray. Through the analysis of cutting forces and observations on chip formation and surface morphology, the effect of cutting speed, feed rate, and heat treatment was quantified, for both cold-sprayed and bulk aluminum 6061. High-speed video of chip formation shows changes in chip form for varying material and heat treatment, which is supported by the force data and quantitative imaging of the machined surface. The results shown in this paper demonstrate that parameters involved in cold spray directly impact on machinability and therefore have implications for machining parameters and strategy.

  7. Control of interfacial intermetallic compounds in Fe–Al joining by Zn addition

    Energy Technology Data Exchange (ETDEWEB)

    Yang, J. [Key Laboratory of Robot and Welding Automation of Jiangxi Province, School of Mechanical and Electrical Engineering, Nanchang University, Nanchang, Jiangxi 330031 (China); Center for Advanced Materials Joining, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 (Canada); Li, Y.L., E-mail: liyulong1112ster@gmail.com [Key Laboratory of Robot and Welding Automation of Jiangxi Province, School of Mechanical and Electrical Engineering, Nanchang University, Nanchang, Jiangxi 330031 (China); Zhang, H. [Key Laboratory of Robot and Welding Automation of Jiangxi Province, School of Mechanical and Electrical Engineering, Nanchang University, Nanchang, Jiangxi 330031 (China); Guo, W. [Center for Advanced Materials Joining, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 (Canada); School of Mechanical Engineering and Automation, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Zhou, Y. [Center for Advanced Materials Joining, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 (Canada)

    2015-10-01

    By Zn addition to the fusion zone, the interfacial intermetallic compounds (IMCs) of laser Al/steel joint changed from layered Fe{sub 2}Al{sub 5} and needle-like FeAl{sub 3} to layered Fe{sub 2}Al{sub 5−x}Zn{sub x} and dispersed FeZn{sub 10} with minor Al-rich amorphous phase. This resulted in an improvement in the joint strength and the change of failure mode.

  8. Effects of combined additions of Sr and AlTiB grain refiners in hypoeutectic Al-Si foundry alloys

    International Nuclear Information System (INIS)

    Lu, L.; Dahle, A.K.

    2006-01-01

    Strontium is the most widely used and a very effective element for modifying the morphology of eutectic silicon, while Ti and B are commonly present in the commercial grain refiners used for Al-Si alloys. Systematic studies on the effects of combined additions of Sr and different AlTiB grain refiners on the Al + Si eutectic and primary aluminium solidification have been performed. While slight coarsening of both eutectic Si and primary aluminium grains occurs during holding, no obvious interactions are observed between Sr and AlTiB grain refiners when the addition level of grain refiners is low. As a result, a well-modified and grain refined structure was obtained. However, strong negative interactions between Sr and Al1.5Ti1.5B were observed as the addition level of the grain refiner increases. It was found that these interactions have a much more profound impact on the eutectic solidification than the primary Al solidification. The melt treated with combined additions of Sr and Al1.5Ti1.5B still shows good grain refinement efficiency even after losing its modification completely. The mechanism responsible for such negative interactions is further discussed

  9. Effects of combined additions of Sr and AlTiB grain refiners in hypoeutectic Al-Si foundry alloys

    Energy Technology Data Exchange (ETDEWEB)

    Lu, L. [CSIRO Minerals, P.O. Box 883, Kenmore, Qld. 4069 (Australia)]. E-mail: Liming.Lu@csiro.au; Dahle, A.K. [CRC for Cast Metals Manufacturing, Division of Materials, School of Engineering, University of Queensland, Brisbane, Qld. 4072 (Australia)

    2006-11-05

    Strontium is the most widely used and a very effective element for modifying the morphology of eutectic silicon, while Ti and B are commonly present in the commercial grain refiners used for Al-Si alloys. Systematic studies on the effects of combined additions of Sr and different AlTiB grain refiners on the Al + Si eutectic and primary aluminium solidification have been performed. While slight coarsening of both eutectic Si and primary aluminium grains occurs during holding, no obvious interactions are observed between Sr and AlTiB grain refiners when the addition level of grain refiners is low. As a result, a well-modified and grain refined structure was obtained. However, strong negative interactions between Sr and Al1.5Ti1.5B were observed as the addition level of the grain refiner increases. It was found that these interactions have a much more profound impact on the eutectic solidification than the primary Al solidification. The melt treated with combined additions of Sr and Al1.5Ti1.5B still shows good grain refinement efficiency even after losing its modification completely. The mechanism responsible for such negative interactions is further discussed.

  10. A novel method to fabricate TiAl intermetallic alloy 3D parts using additive manufacturing

    Directory of Open Access Journals (Sweden)

    J.J.S. Dilip

    2017-04-01

    Full Text Available The present work explores the feasibility of fabricating porous 3D parts in TiAl intermetallic alloy directly from Ti–6Al–4V and Al powders. This approach uses a binder jetting additive manufacturing process followed by reactive sintering. The results demonstrate that the present approach is successful for realizing parts in TiAl intermetallic alloy.

  11. Study of Ni/Si(1 0 0) solid-state reaction with Al addition

    International Nuclear Information System (INIS)

    Huang Yifei; Jiang Yulong; Ru Guoping; Li Bingzong

    2008-01-01

    The characteristics of Ni/Si(1 0 0) solid-state reaction with Al addition (Ni/Al/Si(1 0 0), Ni/Al/Ni/Si(1 0 0) and Al/Ni/Si(1 0 0)) is studied. Ni and Al films were deposited on Si(1 0 0) substrate by ion beam sputtering. The solid-state reaction between metal films and Si was performed by rapid thermal annealing. The sheet resistance of the formed silicide film was measured by four-point probe method. The X-ray diffraction (XRD) was employed to detect the phases in the silicide film. The Auger electron spectroscopy was applied to reveal the element profiles in depth. The influence of Al addition on the Schottky barrier heights of the formed silicide/Si diodes was investigated by current-voltage measurements. The experimental results show that NiSi forms even with the addition of Al, although the formation temperature correspondingly changes. It is revealed that Ni silicidation is accompanied with Al diffusion in Ni film toward the film top surface and Al is the dominant diffusion species in Ni/Al system. However, no Ni x Al y phase is detected in the films and no significant Schottky barrier height modulation by the addition of Al is observed

  12. Effects of Al addition on atomic structure of Cu-Zr metallic glass

    Science.gov (United States)

    Li, Feng; Zhang, Huajian; Liu, Xiongjun; Dong, Yuecheng; Yu, Chunyan; Lu, Zhaoping

    2018-02-01

    The atomic structures of Cu52Zr48 and Cu45Zr48Al7 metallic glasses (MGs) have been studied by molecular dynamic simulations. The results reveal that the molar volume of the Cu45Zr48Al7 MG is smaller than that of the Cu52Zr48 MG, although the size of the Al atom is larger than that of the Cu atom, implying an enhanced atomic packing density achieved by introducing Al into the ternary MG. Bond shortening in unlike atomic pairs Zr-Al and Cu-Al is observed in the Cu45Zr48Al7 MG, which is attributed to strong interactions between Al and (Zr, Cu) atoms. Meanwhile, the atomic packing efficiency is enhanced by the minor addition of Al. Compared with the Cu52Zr48 binary MG, the potential energy of the ternary MG decreases and the glass transition temperature increases. Structural analyses indicate that more Cu- and Al-centered full icosahedral clusters emerge in the Cu45Zr48Al7 MG as some Cu atoms are substituted by Al. Furthermore, the addition of Al leads to more icosahedral medium-range orders in the ternary MG. The increase of full icosahedral clusters and the enhancement of the packing density are responsible for the improved glass-forming ability of Cu45Zr48Al7.

  13. Effects of Mn addition on microstructure and hardness of Al-12.6Si alloy

    Science.gov (United States)

    Biswas, Prosanta; Patra, Surajit; Mondal, Manas Kumar

    2018-03-01

    In this work, eutectic Al-12.6Si alloy with and without manganese (Mn) have been developed through gravity casting route. The effect of Mn concentration (0.0 wt.%, 1 wt%, 2 wt% and 3 wt%) on microstructural morphology and hardness property of the alloy has been investigated. The eutectic Al-12.6 Si alloy exhibits the presence of combine plate, needle and rod-like eutectic silicon phase with very sharp corners and coarser primary silicon particles within the α-Al phase. In addition of 1wt.% of Mn in the eutectic Al-12.6Si alloy, sharp corners of the primary Si and needle-like eutectic Si are became blunt and particles size is reduced. Further, increase in Mn concentration (2.0 wt.%) in the Al-12.6Si alloy, irregular plate shape Al6(Mn,Fe) intermetallics are formed inside the α-Al phase, but the primary and eutectic phase morphology is similar to the eutectic Al-12.6Si alloy. The volume fraction of Al6(Mn,Fe) increases and Al6(Mn,Fe) particles appear as like chain structure in the alloy with 3 wt.% Mn. An increase in Mn concentration in the Al-12.6Si alloys result in the increase in bulk hardness of the alloy as an effects of microstructure modification as well as the presence of harder Al6(Mn,Fe) phase in the developed alloy.

  14. Evolution of Mg-5Al-0.4Mn microstructure after rare earth elements addition

    Directory of Open Access Journals (Sweden)

    A. Żydek

    2011-04-01

    Full Text Available Mg-5Al-0.4Mn-xRE (x = 0, 1, 2, 3 wt.% magnesium alloys were prepared successfully by casting method. The microstructure wasinvestigated by light microscopy. The influence of rare earth (RE elements on the area fraction of eutectic was analysed. The obtainedresults revealed that the as-cast Mg-5Al-0.4Mn alloy consist of α - Mg matrix and eutectic α + γ (where γ is Mg17Al12. However, whilerare earth elements were added to the Mg-Al type alloy, Al11RE3 precipitates were formed. The amount of the Al11RE3 precipitatesincreased with increasing addition of RE, but the amount of γ - Mg17Al12 decreased.

  15. Integrated nanophotonic hubs based on ZnO-Tb(OH3/SiO2 nanocomposites

    Directory of Open Access Journals (Sweden)

    Lin Yu

    2011-01-01

    Full Text Available Abstract Optical integration is essential for practical application, but it remains unexplored for nanoscale devices. A newly designed nanocomposite based on ZnO semiconductor nanowires and Tb(OH3/SiO2 core/shell nanospheres has been synthesized and studied. The unique sea urchin-type morphology, bright and sharply visible emission bands of lanthanide, and large aspect ratio of ZnO crystalline nanotips make this novel composite an excellent signal receiver, waveguide, and emitter. The multifunctional composite of ZnO nanotips and Tb(OH3/SiO2 nanoparticles therefore can serve as an integrated nanophotonics hub. Moreover, the composite of ZnO nanotips deposited on a Tb(OH3/SiO2 photonic crystal can act as a directional light fountain, in which the confined radiation from Tb ions inside the photonic crystal can be well guided and escape through the ZnO nanotips. Therefore, the output emission arising from Tb ions is truly directional, and its intensity can be greatly enhanced. With highly enhanced lasing emissions in ZnO-Tb(OH3/SiO2 as well as SnO2-Tb(OH3/SiO2 nanocomposites, we demonstrate that our approach is extremely beneficial for the creation of low threshold and high-power nanolaser.

  16. Lubrication performance and mechanisms of Mg/Al-, Zn/Al-, and Zn/Mg/Al-layered double hydroxide nanoparticles as lubricant additives

    International Nuclear Information System (INIS)

    Li, Shuo; Bhushan, Bharat

    2016-01-01

    Highlights: • Mg/Al-, Zn/Al- and Zn/Mg/Al-layered double hydroxide were synthesized. • Mg/Al-LDH had superior tribological performance compared to other LDHs. • The best thermal stability of Mg/Al-LDH was responsible for its friction property. - Abstract: Solid lubricant particles are commonly used as oil additives for low friction and wear. Mg/Al-, Zn/Al-, and Zn/Mg/Al-layered double hydroxides (LDH) were synthesized by coprecipitation method. The benefits of LDH nanoparticles are that they can be synthesized using chemical methods where size and shape can be controlled, and can be modified organically to allow dispersal in fluids. The LDH nanoparticles were characterized by X-ray diffraction, scanning electron microscope, thermogravimetry, and differential scanning calorimetry. A pin-on-disk friction and wear tester was used for evaluating the friction and wear properties of LDH nanoparticles as lubricant additives. LDH nanoparticles have friction-reducing and anti-wear properties compared to oil without LDHs. Mg/Al-LDH has the best lubrication, possibly due to better thermal stability in severe conditions.

  17. Lubrication performance and mechanisms of Mg/Al-, Zn/Al-, and Zn/Mg/Al-layered double hydroxide nanoparticles as lubricant additives

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shuo [School of Materials Science and Technology, China University of Geosciences (Beijing), 29 Xueyuan Road, Haidian Distract, Beijing 100083 (China); Nanoprobe Laboratory for Bio- & Nanotechnology and Biomimetics (NLBB), The Ohio State University, 201 W. 19th Avenue Columbus, OH 43210-1142 (United States); Bhushan, Bharat, E-mail: bhushan.2@osu.edu [Nanoprobe Laboratory for Bio- & Nanotechnology and Biomimetics (NLBB), The Ohio State University, 201 W. 19th Avenue Columbus, OH 43210-1142 (United States)

    2016-08-15

    Highlights: • Mg/Al-, Zn/Al- and Zn/Mg/Al-layered double hydroxide were synthesized. • Mg/Al-LDH had superior tribological performance compared to other LDHs. • The best thermal stability of Mg/Al-LDH was responsible for its friction property. - Abstract: Solid lubricant particles are commonly used as oil additives for low friction and wear. Mg/Al-, Zn/Al-, and Zn/Mg/Al-layered double hydroxides (LDH) were synthesized by coprecipitation method. The benefits of LDH nanoparticles are that they can be synthesized using chemical methods where size and shape can be controlled, and can be modified organically to allow dispersal in fluids. The LDH nanoparticles were characterized by X-ray diffraction, scanning electron microscope, thermogravimetry, and differential scanning calorimetry. A pin-on-disk friction and wear tester was used for evaluating the friction and wear properties of LDH nanoparticles as lubricant additives. LDH nanoparticles have friction-reducing and anti-wear properties compared to oil without LDHs. Mg/Al-LDH has the best lubrication, possibly due to better thermal stability in severe conditions.

  18. Synthesis and Application of One-Dimensional La(OH3 Nanostructures: An Overview

    Directory of Open Access Journals (Sweden)

    Xiang Xiao

    2014-01-01

    Full Text Available One-dimensional (1D semiconductor nanomaterials are of particular importance owing to their unique properties and potential applications. This review attempts to provide a comprehensive introduction of 1D La(OH3 nanostructures including nanowires, nanoneedles, nanobelts, and nanorods. Firstly, various strategies developed to fabricate the 1D La(OH3 nanostructures are discussed, such as precipitation and composite-hydroxide-mediated, hydrothermal, and solvothermal methods, accompanying the description of the corresponding growth mechanisms. Then, the unique properties such as novel physical properties of 1D La(OH3 nanostructures resulting from their unique electronic structures and numerous transition modes involving the 4f shells of these ions are represented in detail. Also, the wide applications in photocatalyst, capacitors, and photoluminescence based on the unique properties are discussed. Finally, the paper ends with a summary and some perspectives on the challenges and new directions in this emerging area.

  19. Effects of Be additions on microstructures of TiAl intermetallic compounds

    International Nuclear Information System (INIS)

    Nonaka, Katsuhiko; Tanosaki, Kazuo; Kawabata, Takeshi; Nakajima, Hideo

    1997-01-01

    TiAl-0.1-3.0 mol%Be alloys made by the argon arc melting method were investigated to characterize microstructures in cast and annealed conditions using optical microscopy, SEM, EPMA and X-ray diffractometer. The addition of Be to TiAl resulted in a decrease of α 2 phase, thereby coarsening grains and a shift of γ/(γ+α 2 ) phase boundary to Ti-rich side. Two types of Be compound were observed: one was a few micron size of particles which contain a large amount of oxygen and the other was a coarse and eutectic-like phase (θ) which has an atomic ratio of Ti:Al:Be=41:30:29. The solubility limit of Be in TiAl was less than 0.1 mol%. In the (γ+θ) two phase and (γ+α 2 +θ) three phase regions, an increase of Be addition beyond the solubility limit resulted in a small increase of Ti/Al compositional ratio in γ phase. A volume fraction of lamellar structure in TiAl-Be ternary alloys was smaller in the cast structure but was larger in the annealed structure than that in TiAl binary alloys which have nearly the same Ti/Al ratio as that in the ternary alloys, because the Be addition may increase the stacking fault energy and will stabilize the lamellar twin boundaries, respectively. (author)

  20. Microstructures and Properties Evolution of Al-Cu-Mn Alloy with Addition of Vanadium

    Directory of Open Access Journals (Sweden)

    Fansheng Meng

    2016-12-01

    Full Text Available The effect of the vanadium addition on the microstructure, the precipitation behavior, and the mechanical properties of the Al-5.0Cu-0.4Mn alloy has been studied. The as-cast Al-5.0Cu-0.4Mn alloy was produced by squeeze casting and the heat treatment was carried out following the standard T6 treatment. It is shown that, with the addition of V, grain refinement of aluminum occurred. During heat treatment, the addition of V accelerates the precipitation kinetics of θ′ (Al2Cu phase along the grain boundaries, and promotes the growth rate of the θ′ in the α(Al matrix. Meanwhile, the addition of V retards the precipitation of T (Al20Cu2Mn3 phase. The tensile strength of the Al-5.0Cu-0.4Mn alloy increases with the increase of V content, which can be explained by combined effects of the solid solution strengthening and precipitate strengthening. However, excessively high V addition deteriorates the mechanical properties by forming brittle coarse intermetallic phases.

  1. The Effectiveness of Additional Literacy Support (ALS) in Years 3 and 4

    Science.gov (United States)

    Bunn, Tim

    2008-01-01

    This study compared the progress in reading and spelling of 256 children in 11 classes in 9 English primary schools in Years 3 and 4, and a partially overlapping sample of 126 children who received additional help with literacy during 1 year. Teachers and teaching assistants used either Additional Literacy Support (ALS), a highly structured set of…

  2. Magnetic and structural properties of yellow europium oxide compound and Eu(OH)3

    International Nuclear Information System (INIS)

    Lee, Dongwook; Seo, Jiwon; Valladares, Luis de los Santos; Avalos Quispe, O.; Barnes, Crispin H.W.

    2015-01-01

    A new material based on a yellow europium oxide compound was prepared from europium oxide in a high vacuum environment. The structural and magnetic properties of the material were investigated. Owing to the absence of a crystal structure, the material exhibited a disordered magnetic behavior. In a reaction with deionized (DI) water without applied heat, the compound assumed a white color as soon as the DI water reached the powder, and the structure became polycrystalline Eu(OH) 3 . The magnetic properties, such as the thermal hysteresis, disappeared after the reaction with DI water, and the magnetic susceptibility of the yellow oxide compound weakened. The magnetic properties of Eu(OH) 3 were also examined. Although Eu 3+ is present in Eu(OH) 3 , a high magnetic moment due to the crystal field effect was observed. - Graphical abstract: (top left) Optical image of the yellow europium oxide compound. (top right) Optical image of the product of DI water and yellow europium oxide. (bottom) Magnetization curves as a function of temperature measured in various magnetic field. - Highlights: • We prepared a new material based on a yellow europium oxide compound from europium oxide. • We characterized the magnetic properties of the material which exhibits a disordered magnetic behavior such as thermal hysteresis. • The compound turned white (Eu(OH) 3 ) as soon as the DI water reached the powder. • The thermal hysteresis disappeared after the reaction with DI water and the magnetic susceptibility of the yellow oxide compound weakened

  3. Crystal structure and stability of LiAlD4 with TiF3 additive

    International Nuclear Information System (INIS)

    Brinks, H.W.; Fossdal, A.; Fonnelop, J.E.; Hauback, B.C.

    2005-01-01

    LiAlD 4 samples with TiF 3 additives have been investigated by synchrotron X-ray diffraction, neutron diffraction and a Sieverts-type apparatus. Directly after ball milling there are no signs of any Ti-containing phases, and the unit-cell of LiAlD 4 and Al give no indication of any solid solutions. Hence it is concluded that the Ti is in an amorphous state directly after ball milling. Furthermore, no LiF was observed in the samples. Based on Sieverts-type measurements the plateau pressure at 80 deg C has been proved to be higher than 85 bar. Samples stored in a glove box are slowly desorbed, and after 6 months for a LiAlD 4 + TiF 3 sample, the reaction to LiD + Al is nearly finished

  4. Structure and mechanical properties of TiZr binary alloy after Al addition

    International Nuclear Information System (INIS)

    Jiang, X.J.; Jing, R.; Liu, C.Y.; Ma, M.Z.; Liu, R.P.

    2013-01-01

    Microstructure and mechanical properties of hot-rolled TiZrAl alloys were studied. The results showed that the microstructure of all alloys mainly consisted of lamellar α phase. The thickness of the lamellar α phase gradually increased with increasing aluminum content. Moreover, large numbers of stacking faults was observed in Ti–25Zr–15Al (at%) alloy. The aluminum addition strongly affected the mechanical properties of the TiZrAl alloys. With increased aluminum contents, the strength increased evidently, whereas, the elongation decreased. Ti–25Zr–15Al (at%) with the highest aluminum contents in all alloys, possessed the highest tensile strength (σ b =1319 MPa), i.e. strengthened by 41% compared with Ti–25Zr (at%) alloy, and still retained the elongation of 5.5%. According to the classical size and/or modulus misfits model, the effect of aluminum addition was significant in TiZr alloys because of the considerable misfits between aluminum and zirconium

  5. Homogeneous and Heterogeneous (Fex, Cr1-x)(OH)3 Precipitation: Implications for Cr Sequestration.

    Science.gov (United States)

    Dai, Chong; Zuo, Xiaobing; Cao, Bo; Hu, Yandi

    2016-02-16

    The formation of (Fe, Cr)(OH)3 nanoparticles determines the fate of aqueous Cr in many aquatic environments. Using small-angle X-ray scattering, precipitation rates of (Fe, Cr)(OH)3 nanoparticles in solution and on quartz were quantified from 0.1 mM Fe(III) solutions containing 0-0.25 mM Cr(III) at pH = 3.7 ± 0.2. Concentration ratio of aqueous Cr(III)/Fe(III) controlled the chemical composition (x) of (Fex, Cr1-x)(OH)3 precipitates, solutions' supersaturation with respect to precipitates, and the surface charge of quartz. Therefore, the aqueous Cr(III)/Fe(III) ratio affected homogeneous (in solution) and heterogeneous (on quartz) precipitation rates of (Fex, Cr1-x)(OH)3 through different mechanisms. The sequestration mechanisms of Cr(III) in precipitates were also investigated. In solutions with high aqueous Cr(III)/Fe(III) ratios, surface enrichment of Cr(III) on the precipitates occurred, resulting in slower particle growth in solutions. From solutions with 0-0.1 mM Cr(III), the particles on quartz grew from 2 to 4 nm within 1 h. Interestingly, from solution with 0.25 mM Cr(III), particles of two distinct sizes (2 and 6 nm) formed on quartz, and their sizes remained unchanged throughout the reaction. Our study provided new insights on homogeneous and heterogeneous precipitation of (Fex, Cr1-x)(OH)3 nanoparticles, which can help determine the fate of Cr in aquatic environments.

  6. Instability of TiC and TiAl3 compounds in Al-10Mg and Al-5Cu alloys by addition of Al-Ti-C master alloy

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The performance of Al-Ti-C master alloy in refining Al-10Mg and A1-5Cu alloys was studied by using electron probe micro-analyzer (EPMA) and X-ray diffractometer (XRD) analysis.The results indicate that there are obvious fading phenomena in both Al-10Mg and Al-5Cu alloys with the addition of Al-5Ti-0.4C refiner which contains TiC and TiAl3 compounds.Mg element has no influence on the stability of TiC and TiAl3, while TiC particles in Al-10Mg alloy react with Al to form Al4C3 particles, resulting in the refinement fading.However, TiC particles are relatively stable in Al-5Cu alloy, while TiAl3 phase reacts with Al2Cu to produce a new phase Ti(Al, Cu)2, which is responsible for the refinement fading in Al-5Cu alloy.These indicate that the refinement fading will not occur only when both the TiC particles and TiAl3 compound of Al-Ti-C refiner are stable in Al alloys.

  7. A Review of the Fatigue Properties of Additively Manufactured Ti-6Al-4V

    Science.gov (United States)

    Cao, Fei; Zhang, Tiantian; Ryder, Matthew A.; Lados, Diana A.

    2018-03-01

    Various additive manufacturing (AM) technologies have been used to fabricate Ti-6Al-4V. The fatigue performance of Ti-6Al-4V varies from process to process. In this review, fatigue properties of Ti-6Al-4V alloys made by different AM technologies and post-fabrication treatments were compiled and discussed to correlate with the materials' characteristic features, primarily surface roughness and porosity. Microstructure anisotropy and porosity effects on fatigue crack growth and fatigue life are also presented and discussed. A modified Kitagawa-Takahashi diagram developed from current available fatigue data was used to quantify the influence of defects on fatigue strength. This review aims to assist in selecting/optimizing AM processes to achieve high fatigue resistance in Ti-6Al-4V, as well as provide a better understanding of the advantages and limitations of current AM techniques in producing titanium alloys.

  8. Effects of La and Ce Addition on the Modification of Al-Si Based Alloys

    Directory of Open Access Journals (Sweden)

    Emad M. Elgallad

    2016-01-01

    Full Text Available This study focuses on the effects of the addition of rare earth metals (mainly lanthanum and cerium on the eutectic Si characteristics in Al-Si based alloys. Based on the solidification curves and microstructural examination of the corresponding alloys, it was found that addition of La or Ce increases the alloy melting temperature and the Al-Si eutectic temperature, with an Al-Si recalescence of 2-3°C, and the appearance of post-α-Al peaks attributed to precipitation of rare earth intermetallics. Addition of La or Ce to Al-(7–13% Si causes only partial modification of the eutectic Si particles. Lanthanum has a high affinity to react with Sr, which weakens the modification efficiency of the latter. Cerium, however, has a high affinity for Ti, forming a large amount of sludge. Due to the large difference in the length of the eutectic Si particles in the same sample, the normal use of standard deviation in this case is meaningless.

  9. Ductility and fracture of single crystaliine Ni3Al with boron additions

    International Nuclear Information System (INIS)

    Heredia, F.E.; Pope, D.P.

    1989-01-01

    Low and high temperature tensile tests were performed on single crystals of pure Ni 3 Al and Ni 3 Al+B in order to determine the effect of B additions on the ductility and fracture behavior. Tests were carried out in air at a constant strain rate of 1/3 x 10 -3 s -1 . The orientation tested were [001] for whic the yield stress in tension is always greater than in compression, and those for wich the tension/compression asymmetry is zero ([T=C]) for each particular composition. At room temperature, the results show a positive effect of B additions on both the fracture stress and on the ductility. The ductility at 800K appears to decrease monotonically with B additions. The largest ductilities are found for [T=C] at room temperature where an improvement of about 26% (resolved strain) for an addition of 0.2 at % B was obtained. However, the most dramatic increase in ductility occurs for the [001] oriented samples at room temperature where a 55% improvement was measured over that of pure Ni 3 Al. Fracture surfaces show a combinaton of massive slip, some clevage, and heavily dimpled areas. These observations show that B additions not only increase the ductility of polycrystalline Ni 3 Al, as has been previously observed by many investigators, but also that the already-ductile single crystalline material, indicating that a bulk effect should be added to the grain boundary strengthening effect of B when explaining the improvement in ductility of polycrystalline Ni 3 Al due to B additions

  10. In-situ alloyed LENS additively manufactured TiAl-Nb structure

    CSIR Research Space (South Africa)

    Tlotleng, Monnamme

    2017-11-01

    Full Text Available corporates are interested in developments that will lead to cost effective manufacturing technologies that are able to produce homogenous, defect free TiAl structures. Additive manufacturing is one promising technology hence it was explored here in studying...

  11. Studies of Gravity Waves Using Michelson Interferometer Measurements of OH (3-1) Bands

    Science.gov (United States)

    Won, Young-In; Cho, Young-Min; Lee, Bang Yong; Kim, J.

    2001-06-01

    As part of a long-term program for polar upper atmospheric studies, temperatures and intensities of the OH (3-1) bands were derived from spectrometric observations of airglow emissions over King Sejong station (62.22o S, 301.25o E). These measurements were made with a Michelson interferometer to cover wavelength regions between 1000 nm and 2000 nm. A spectral analysis was performed to individual nights of data to acquire information on the waves in the upper mesosphere/lower thermosphere. It is assumed that the measured fluctuations in the intensity and temperature of the OH (3-1) airglow were caused by gravity waves propagating through the emission layer. Correlation of intensity and temperature variation revealed oscillations with periods ranging from 2 to 9 hours. We also calculated Krassovsky's parameter and compared with published values.

  12. Studies of Gravity Waves Using Michelson Interferometer Measurements of OH (3-1 Bands

    Directory of Open Access Journals (Sweden)

    Young-In Won

    2001-06-01

    Full Text Available As part of a long-term program for polar upper atmospheric studies, temperatures and intensities of the OH (3-1 bands were derived from spectrometric observations of airglow emissions over King Sejong station (62.22o S, 301.25o E. These measurements were made with a Michelson interferometer to cover wavelength regions between 1000 nm and 2000 nm. A spectral analysis was performed to individual nights of data to acquire information on the waves in the upper mesosphere/lower thermosphere. It is assumed that the measured fluctuations in the intensity and temperature of the OH (3-1 airglow were caused by gravity waves propagating through the emission layer. Correlation of intensity and temperature variation revealed oscillations with periods ranging from 2 to 9 hours. We also calculated Krassovsky's parameter and compared with published values.

  13. Role of cerium, lanthanum, and strontium additions in an Al-Si-Mg (A356) alloy

    Energy Technology Data Exchange (ETDEWEB)

    Nabawy, Ahmed M.; Samuel, Agnes M.; Samuel, Fawzy H. [Universite du Quebec, Chicoutimi (Canada). Dept. des Sciences Appliquees; Alkahtani, Saleh A.; Abuhasel, Khaled A. [Salman Bin Abdulaziz Univ., Riyadh (Saudi Arabia). Mechanical Engineering Dept.

    2016-05-15

    The effects of individual and combined additions of cerium (Ce), lanthanum (La), and strontium (Sr) on the eutectic modification and solidification characteristics of an Al-Si-Mg (A356) aluminum alloy were investigated using optical microscopy and thermal analysis techniques. Addition of Ce, La, and Sr resulted in different depression levels of the eutectic nucleation temperature and eutectic growth undercooling, generating modified eutectic structures exhibiting different levels of modification. Microstructural results showed that the best modification levels using individual additions were achieved by Sr which produced a fine fibrous eutectic structure, followed by La, which produced a refined lamellar structure, with Ce providing the lowest level of modification. On the other hand, a combined addition of Ce and Sr provided the highest modification level, with the production of a very fine fibrous eutectic silicon structure. In general, the addition of Sr helped to further increase the refinement obtained in the alloys containing La or Ce + La additions. In the latter alloy, the main intermetallic phases observed were La(Al,Si){sub 2} and Al{sub 20}(La,Ce)Ti{sub 2}Si. The improved modification levels were found to be proportional to the depression in the eutectic nucleation temperature and the eutectic growth undercooling. A high cooling rate also improved the modification level by at least one level.

  14. Synthesis, characterization and flocculation activity of novel Fe(OH)3-polyacrylamide hybrid polymer

    International Nuclear Information System (INIS)

    Wang Huilong; Cui Jinyan; Jiang Wenfeng

    2011-01-01

    Highlights: → The preparation of a novel Fe(OH) 3 -PAM hybrid polymer flocculant is achieved via free radical solution polymerization. → Flocculation of kaolin suspensions using this novel Fe(OH) 3 -PAM hybrid polymer flocculant is revealed in this study. → The statistical model was first applied for calculating the thermodynamic parameters for the kaolin flocculating process. - Abstract: A novel Fe(OH) 3 -polyacrylamide inorganic-organic hybrid polymer (FHPAM) was synthesized via free radical solution polymerization initiated by a redox initiation system ((NH 4 ) 2 S 2 O 8 -NaHSO 3 ) in an aqueous medium. Reaction parameters influencing the intrinsic viscosity and the yield of the hybrid polymer, such as initiator concentration, monomer mass fraction, temperature and reaction time were investigated and optimized. The results show that the maximum intrinsic viscosity and up to 94% yields of the hybrid polymer can be achieved using initiator concentration of 0.3% with acrylamide monomer mass fraction of 20% under solution polymerization at 40 deg. C for 7 h. The physicochemical properties of this hybrid flocculant were characterized with TEM, FTIR spectra, TGA, and conductivity. It was found that a chemical bond exists between Fe(OH) 3 colloid and polyacrylamide chains in the FHPAM. The application of the hybrid polymer for the treatment of 2.5 g L -1 kaolin suspension indicates that it had an excellent flocculation capacity and its flocculation efficiency was much better than that of commercial available polyacrylamide (PAM) and polymeric ferric sulfate (PFS). The optimal conditions for the flocculation treatment of kaolin suspension were the FHPAM dosage of 40 mg L -1 at pH 7.0. The thermodynamic parameters for the flocculation process were calculated based on a statistical model. Interpretation of the results was given.

  15. Low silicon U(Al,Si)3 stabilization by Zr addition

    International Nuclear Information System (INIS)

    Pizarro, L.M.; Alonso, P.R.; Rubiolo, G.H.

    2009-01-01

    Previous knowledge states that (U,Zr)Al 3 and U(Al,Si) 3 phases with Zr and Si content higher than 6 at.% (7.7 wt%) and 4 at.% (1.4 wt%), respectively, does not partially transform to UAl 4 at 600 o C. In this work, four alloys within the quaternary system U-Al-Si-Zr were made with a fixed nominal 0.18 at.% (0.1 wt%) Si content in order to assess the synergetic effect of both Zr and Si alloying elements to the thermodynamic stability of the (U,Zr)(Al,Si) 3 phase. Heat treatments at 600 deg. C were undertaken and samples were analyzed by means of XRD, EPMA and EDS techniques. A remarkable conclusion is that addition of 0.3 at.% Si in the (U,Zr)(Al,Si) 3 phase reduces in 2.7 at.% the necessary Zr content to inhibit its transformation to U(Al,Si) 4 .

  16. Mechanical properties of Fe3Al-based alloys with addition of carbon, niobium and titanium

    International Nuclear Information System (INIS)

    Zhang Zhengrong; Liu Wenxi

    2006-01-01

    Several Fe 3 Al-based iron aluminides with the addition of alloying elements carbon, niobium and titanium were produced by vacuum induction melting (VIM) and hot spinning forging. Analytic techniques including transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used in studying the microstructure and fracture manner of these alloys. The results show that due to the addition of alloying elements, the superlattice dislocations tend towards multiple slipping, leaving behind on their slip plane ribbons of square-shaped slip-induced antiphase boundaries. The elongation of Fe 3 Al in tension at room temperature increased to about 10% by the addition of suitable alloying elements, the usage of thermo-mechanical processing that has the function of refining grains and substructures, and subsequent annealing

  17. Measurement of casting parameters in ZnAlCu3 molds created by additive technology

    Directory of Open Access Journals (Sweden)

    S. Medić

    2016-10-01

    Full Text Available This paper examines the parameters of casting ZnAl4Cu3 alloy (volume, castability, density and occupancy of the mold in mold made additive technology. Molds made by additive technology are: cheaper in production of a small number of castings, geometrically more accurate and faster made. From obtained results of this paper it is clearly seen that printed mold must be protected with thermal coating because liquid adhesive of powder otherwise evaporates during casting and creates additional moisture in the mold, as it was noted.

  18. Effect of CeLa addition on the microstructures and mechanical properties of Al-Cu-Mn-Mg-Fe alloy

    International Nuclear Information System (INIS)

    Du, Jiandi; Ding, Dongyan; Xu, Zhou; Zhang, Junchao; Zhang, Wenlong; Gao, Yongjin; Chen, Guozhen; Chen, Weigao; You, Xiaohua; Chen, Renzong; Huang, Yuanwei; Tang, Jinsong

    2017-01-01

    Development of high strength lithium battery shell alloy is highly desired for new energy automobile industry. The microstructures and mechanical properties of Al-Cu-Mn-Mg-Fe alloy with different CeLa additions were investigated through optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Rietveld refinement and tensile testing. Experimental results indicate that Al 8 Cu 4 Ce and Al 6 Cu 6 La phases formed due to CeLa addition. Addition of 0.25 wt.% CeLa could promote the formation of denser precipitation of Al 20 Cu 2 Mn 3 and Al 6 (Mn, Fe) phases, which improved the mechanical properties of the alloy at room temperature. However, up to 0.50 wt.% CeLa addition could promote the formation of coarse Al 8 Cu 4 Ce phase, Al 6 Cu 6 La phase and Al 6 (Mn, Fe) phase, which resulted in weakened mechanical properties. - Highlights: •Al-Cu-Mn-Mg-Fe alloys with different CeLa addition were fabricated through casting and rolling. •Al 8 Cu 4 Ce and Al 6 Cu 6 La phases formed after CeLa addition. •Addition of 0.25 wt.% CeLa promoted formation of denser precipitates of Al 20 Cu 2 Mn 3 and Al 6 (Mn, Fe). •Mechanical properties of the alloy was improved after 0.25 wt.% CeLa addition.

  19. Production of Al-Ti-C grain refiners with the addition of elemental carbon

    International Nuclear Information System (INIS)

    Gezer, Berke Turgay; Toptan, Fatih; Daglilar, Sibel; Kerti, Isil

    2010-01-01

    Grain refining process used in aluminium alloys, has an important role for preventing columnar, coarse grains and encouraging fine, equiaxed grain formation. Al-Ti-B grain refiners are widely used as aluminium grain refiners despite the problems in application Al-Ti-C refiners have an increasing demand in recent years. In the present work, Al-Ti-C grain refiners with different Ti:C ratios were produced by insitu method with the addition of elemental carbon. Microstructures were characterised by optic microscope and scanning electron microscope equipped with energy dispersive spectroscopy. The effects of temperature, holding time and Ti:C ratio on the grain refinement process were investigated and optimum conditions were determined.

  20. The effect of Al and Cr additions on pack cementation zinc coatings

    International Nuclear Information System (INIS)

    Chaliampalias, D.; Papazoglou, M.; Tsipas, S.; Pavlidou, E.; Skolianos, S.; Stergioudis, G.; Vourlias, G.

    2010-01-01

    Zinc is widely used as a protective coating material due to its corrosion resistant properties. The structure and oxidation resistance of Al and Cr mixed zinc coatings, deposited by pack cementation process, is thoroughly examined in this work. The morphology and chemical composition of the as-deposited and oxidized samples was accomplished by electron microscopy while the phase identification was performed by XRD diffraction analysis. The experimental results showed that the addition of aluminum or chromium in the pack mixture forms only Al and Cr rich phases on the surface of the specimens without affecting significantly the phase composition of the rest zinc coatings. In the case of Zn-Al coatings, the overlying layer contains high concentrations of Al together with lower amounts of zinc and iron and in Zn-Cr coatings this layer contains Cr, Fe and Zn atoms and has much smaller thickness. The presence of these additional layers promotes significantly the oxidation resistance of the zinc pack coatings and they preserve most of their initial thickness and chemical content when exposed to an aggressive environment while their oxidation mass gain was measured at low levels during the oxidation tests.

  1. Additive manufactured Ti6Al4V scaffolds with the RF- magnetron sputter deposited hydroxyapatite coating

    International Nuclear Information System (INIS)

    Chudinova, E; Surmeneva, M; Surmenev, R; Koptioug, A; Scoglund, P

    2016-01-01

    Present paper reports on the results of surface modification of the additively manufactured porous Ti6Al4V scaffolds. Radio frequency (RF) magnetron sputtering was used to modify the surface of the alloy via deposition of the biocompatible hydroxyapatite (HA) coating. The surface morphology, chemical and phase composition of the HA-coated alloy were studied. It was revealed that RF magnetron sputtering allows preparing a homogeneous HA coating onto the entire surface of scaffolds. (paper)

  2. Effect of Ternary Addition of Iron on Shape Memory Characteristics of Cu-Al Alloys

    Science.gov (United States)

    Raju, T. N.; Sampath, V.

    2011-07-01

    The effect of alloying Cu-Al alloys with Fe on their transformation temperatures and shape memory properties was investigated by differential scanning calorimetry and bend test. It was found that the minor additions of iron resulted in change of transformation temperatures and led to excellent shape memory properties of the alloys. Since the transformation temperatures are high, they are an ideal choice for high-temperature applications.

  3. The Effects of Cr and Al Addition on Transformation and Properties in Low‐Carbon Bainitic Steels

    OpenAIRE

    Junyu Tian; Guang Xu; Mingxing Zhou; Haijiang Hu; Xiangliang Wan

    2017-01-01

    Three low‐carbon bainitic steels were designed to investigate the effects of Cr and Al addition on bainitic transformation, microstructures, and properties by metallographic method and dilatometry. The results show that compared with the base steel without Cr and Al addition, only Cr addition is effective for improving the strength of low‐carbon bainitic steel by increasing the amount of bainite. However, compared with the base steel, combined addition of Cr and Al has no significant effect o...

  4. K-capture by Al-Si based Additives in an Entrained Flow Reactor

    DEFF Research Database (Denmark)

    Wang, Guoliang; Jensen, Peter Arendt; Wu, Hao

    2016-01-01

    A water slurry, consisting of KCl and Al-Si based additives (kaolin and coal fly ash) was fed into an entrained flow reactor (EFR) to study the K-capturing reaction of the additives at suspension-fired conditions. Solid products collected from the reactor were analysed with respect to total...... of KCl to K-aluminosilicate decreased. When reaction temperature increased from 1100 °C to 1450 °C, the conversion of KCl does not change significantly, which differs from the trend observed in fixed-bed reactor....

  5. Ti-6Al-4V Additively Manufactured by Selective Laser Melting with Superior Mechanical Properties

    Science.gov (United States)

    Xu, W.; Sun, S.; Elambasseril, J.; Liu, Q.; Brandt, M.; Qian, M.

    2015-03-01

    The Achilles' heel of additively manufactured Ti-6Al-4V by selective laser melting (SLM) is its inferior mechanical properties compared with its wrought (forged) counterparts. Acicular α' martensite resulted from rapid cooling by SLM is primarily responsible for high strength but inadequate tensile ductility achieved in the as-fabricated state. This study presents a solution to eliminating the adverse effect of the nonequilibrium α' martensite. This is achieved by enabling in situ martensite decomposition into a novel ultrafine (200-300 nm) lamellar ( α + β) microstructure via the selection of an array of processing variables including the layer thickness, energy density, and focal offset distance. The resulting tensile elongation reached 11.4% while the yield strength was kept above 1100 MPa. These properties compare favorably with those of mill-annealed Ti-6Al-4V consisting of globular α and β. The fatigue life of SLM-fabricated Ti-6Al-4V with an ultrafine lamellar ( α + β) structure has approached that of the mill-annealed counterparts and is much superior to that of SLM-fabricated Ti-6Al-4V with α' martensite.

  6. Selective synthesis of clinoatacamite Cu2(OH)3Cl and tenorite CuO nanoparticles by pH control

    DEFF Research Database (Denmark)

    Engelbrekt, Christian; Malcho, Phillip; Andersen, Jonas

    2014-01-01

    , it directed the growth of Cu2(OH)3Cl to provide pure clinoatacamite without the presence of related poly- morphs. The products were characterized by transmission electron microscopy, infrared spectroscopy, ultraviolet–visible light spectroscopy, X-ray powder diffraction (XRD), scanning transmission X......-ray microscopy and atomic force microscopy. Infrared spectroscopy was essential for characterization of closely related polymorphs of Cu2(OH)3Cl indistinguishable by XRD. A plausible mechanism has been proposed and discussed for the formation of the CuO and Cu2(OH)3Cl nanostructures....

  7. Comparison Study on Additive Manufacturing (AM) and Powder Metallurgy (PM) AlSi10Mg Alloys

    Science.gov (United States)

    Chen, B.; Moon, S. K.; Yao, X.; Bi, G.; Shen, J.; Umeda, J.; Kondoh, K.

    2018-02-01

    The microstructural and mechanical properties of AlSi10Mg alloys fabricated by additive manufacturing (AM) and powder metallurgy (PM) routes were investigated and compared. The microstructures were examined by scanning electron microscopy assisted with electron-dispersive spectroscopy. The crystalline features were studied by x-ray diffraction and electron backscatter diffraction. Room-temperature tensile tests and Vickers hardness measurements were performed to characterize the mechanical properties. It was found that the AM alloy had coarser Al grains but much finer Si precipitates compared with the PM alloy. Consequently, the AM alloy showed more than 100% increment in strength and hardness compared with the PM alloy due to the presence of ultrafine forms of Si, while exhibiting moderate ductility.

  8. Characterization of Ti-6Al-4V produced via electron beam additive manufacturing

    Science.gov (United States)

    Hayes, Brian J.

    In recent years, additive manufacturing (AM) has become an increasingly promising method used for the production of structural metallic components. There are a number of reasons why AM methods are attractive, including the ability to produce complex geometries into a near-net shape and the rapid transition from design to production. Ti-6Al-4V is a titanium alloy frequently used in the aerospace industry which is receiving considerable attention as a good candidate for processing via electron beam additive manufacturing (EBAM). The Sciaky EBAM method combines a high-powered electron beam, weld-wire feedstock, and a large build chamber, enabling the production of large structural components. In order to gain wide acceptance of EBAM of Ti-6Al-4V as a viable manufacturing method, it is important to understand broadly the microstructural features that are present in large-scale depositions, including specifically: the morphology, distribution and texture of the phases present. To achieve such an understanding, stereological methods were used to populate a database quantifying key microstructural features in Ti-6Al-4V including volume fraction of phases, alpha lath width, colony scale factor, and volume fraction of basket weave type microstructure. Microstructural features unique to AM, such as elongated grains and banded structures, were also characterized. Hardness and tensile testing were conducted and the results were related to the microstructural morphology and sample orientation. Lastly, fractured surfaces and defects were investigated. The results of these activities provide insight into the process-structure-properties relationships found in EBAM processed Ti-6Al-4V.

  9. Microstructural characterisation of Al-Si cast alloys containing rare earth additions

    Science.gov (United States)

    Elgallad, E. M.; Ibrahim, M. F.; Doty, H. W.; Samuel, F. H.

    2018-05-01

    This paper presents a thorough study on the effect of rare earth elements, specifically La and Ce, on the microstructure characteristics of non-modified and Sr-modified A356 and A413 alloys. Several alloys were prepared by adding 1% La and 1% Ce either individually or in combination. Microstructural characterisation was carried out using optical microscopy, scanning electron microscopy and electron probe microanalysis as well as differential scanning calorimetry (DSC) analysis. The results showed that the individual and combined additions of La and Ce did not bring about any modification or even refinement in the eutectic Si structure. Moreover, these additions were found to negate the modification effect of Sr, particularly in the presence of La. The A356 and A413 alloys containing La and/or Ce displayed high phase volume fractions owing to the formation of Al-Si-La/Ce/(La,Ce) and Al-Ti-La/Ce intermetallic phases. DSC analysis revealed that the formation temperatures of these phases varied from 560 to 568 °C and 568 to 574 °C, respectively. This analysis also showed that the addition of La and Ce whether individually or in combination resulted in a depression in the eutectic temperature and a considerable increase in the solidification range, particularly for the A413 alloy.

  10. Effects of Zr Addition on Strengthening Mechanisms of Al-Alloyed High-Cr ODS Steels.

    Science.gov (United States)

    Ren, Jian; Yu, Liming; Liu, Yongchang; Liu, Chenxi; Li, Huijun; Wu, Jiefeng

    2018-01-12

    Oxide dispersion strengthened (ODS) steels with different contents of zirconium (denoted as 16Cr ODS, 16Cr-0.3Zr ODS and 16Cr-0.6Zr ODS) were fabricated to investigate the effects of Zr on strengthening mechanism of Al-alloyed 16Cr ODS steel. Electron backscatter diffraction (EBSD) results show that the mean grain size of ODS steels could be decreased by Zr addition. Transmission electron microscope (TEM) results indicate that Zr addition could increase the number density but decrease the mean diameter and inter-particle spacing of oxide particles. Furthermore, it is also found that in addition to Y-Al-O nanoparticles, Y-Zr-O oxides with finer size were observed in 16Cr-0.3Zr ODS and 16Cr-0.6Zr ODS steels. These changes in microstructure significantly increase the yield strength (YS) and ultimate tensile strength (UTS) of ODS steels through mechanisms of grain boundary strengthening and dispersion strengthening.

  11. Microstructural discovery of Al addition on Sn–0.5Cu-based Pb-free solder design

    International Nuclear Information System (INIS)

    Koo, Jahyun; Lee, Changsoo; Hong, Sung Jea; Kim, Keun-Soo; Lee, Hyuck Mo

    2015-01-01

    It is important to develop Pb-free solder alloys suitable for automotive use instead of traditional Sn–Pb solder due to environmental regulations (e.g., Restriction of Hazardous Substances (RoHS)). Al addition has been spotlighted to enhance solder properties. In this study, we investigated the microstructural change of Sn–0.5Cu wt.% based Pb-free solder alloys with Al addition (0.01–0.05 wt.%). The small amount of Al addition caused a remarkable microstructural change. The Al was favored to form Cu–Al intermetallic compounds inside the solder matrix. We identified the Cu–Al intermetallic compound as Cu_3_3Al_1_7, which has a rhombohedral structure, using EPMA and TEM analyses. This resulted in refined Cu_6Sn_5 networks in the Sn–0.5Cu based solder alloy. In addition, we conducted thermal analysis to confirm its stability at a high temperature of approximately 230 °C, which is the necessary temperature range for automotive applications. The solidification results were substantiated thermodynamically using the Scheil solidification model. We can provide criteria for the minimum aluminum content to modify the microstructure of Pb-free solder alloys. - Graphical abstract: The minor Al additions refined eutectic Cu_6Sn_5 IMC networks on the Sn–0.5Cu based solder alloys. The microstructure was dramatically changed with the minor Al addition. - Highlights: • We observed dramatic microstructure-change with Al additions. • We defined Cu_3_3Al_1_7 IMC with Al additions using TEM analysis. • We investigated grain refinement with Al additions using EBSD. • We discussed the refinement based on Scheil solidification model.

  12. Microstructural discovery of Al addition on Sn–0.5Cu-based Pb-free solder design

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Jahyun; Lee, Changsoo [Department of Materials Science and Engineering, KAIST, Daejeon 305-701 (Korea, Republic of); Hong, Sung Jea [MK Electron Co., Ltd., Yongin Cheoin-gu 316-2 (Korea, Republic of); Kim, Keun-Soo, E-mail: keunsookim@hoseo.edu [Department of Display Engineering, Hoseo University, Asan 336-795 (Korea, Republic of); Lee, Hyuck Mo, E-mail: hmlee@kaist.ac.kr [Department of Materials Science and Engineering, KAIST, Daejeon 305-701 (Korea, Republic of)

    2015-11-25

    It is important to develop Pb-free solder alloys suitable for automotive use instead of traditional Sn–Pb solder due to environmental regulations (e.g., Restriction of Hazardous Substances (RoHS)). Al addition has been spotlighted to enhance solder properties. In this study, we investigated the microstructural change of Sn–0.5Cu wt.% based Pb-free solder alloys with Al addition (0.01–0.05 wt.%). The small amount of Al addition caused a remarkable microstructural change. The Al was favored to form Cu–Al intermetallic compounds inside the solder matrix. We identified the Cu–Al intermetallic compound as Cu{sub 33}Al{sub 17}, which has a rhombohedral structure, using EPMA and TEM analyses. This resulted in refined Cu{sub 6}Sn{sub 5} networks in the Sn–0.5Cu based solder alloy. In addition, we conducted thermal analysis to confirm its stability at a high temperature of approximately 230 °C, which is the necessary temperature range for automotive applications. The solidification results were substantiated thermodynamically using the Scheil solidification model. We can provide criteria for the minimum aluminum content to modify the microstructure of Pb-free solder alloys. - Graphical abstract: The minor Al additions refined eutectic Cu{sub 6}Sn{sub 5} IMC networks on the Sn–0.5Cu based solder alloys. The microstructure was dramatically changed with the minor Al addition. - Highlights: • We observed dramatic microstructure-change with Al additions. • We defined Cu{sub 33}Al{sub 17} IMC with Al additions using TEM analysis. • We investigated grain refinement with Al additions using EBSD. • We discussed the refinement based on Scheil solidification model.

  13. Dynamic tensile behavior of electron beam additive manufactured Ti6Al4V

    International Nuclear Information System (INIS)

    Rodriguez, O.L.; Allison, P.G.; Whittington, W.R.; Francis, D.K.; Rivera, O.G.; Chou, K.; Gong, X.; Butler, T.M.; Burroughs, J.F.

    2015-01-01

    High rate and quasi-static tensile experiments examined strain rate dependence on flow stress and strain hardening of additive manufactured Ti6Al4V. Variations on strain-hardening coefficient indicate that the rate of thermal softening is greater than strain hardening during plastic deformation. Strain rate sensitivity calculations within the plastic strain regime suggest changes in deformation mechanisms. Fractography revealed cup-and-cone fracture for quasi-static samples and shear mechanisms for high rate samples. As-deposited microstructure consisted of bimodal α+β with the presence of secondary martensitic phase

  14. Effect of scandium additions on microstructure and mechanical properties of Al-Zn-Mg alloy welds

    International Nuclear Information System (INIS)

    Dev, Selvi; Stuart, A. Archibald; Kumaar, R.C. Ravi Dev; Murty, B.S.; Rao, K. Prasad

    2007-01-01

    The microstructure and mechanical properties of fusion zones of medium strength Al-Zn-Mg alloy (RDE-40) welds obtained by using different fillers containing various amount of scandium was investigated. It was observed that addition of scandium led to very significant grain refinement in the fusion zone especially for scandium levels greater than the eutectic composition (0.55 wt%). The grain refinement led to the reduction in solidification cracking and improved the tensile properties of fusion zone compared to the ones obtained by the commercial AA5556 filler

  15. Dynamic tensile behavior of electron beam additive manufactured Ti6Al4V

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, O.L. [Department of Mechanical Engineering, University of Alabama, Tuscaloosa, AL 35487 (United States); Allison, P.G., E-mail: pallison@eng.ua.edu [Department of Mechanical Engineering, University of Alabama, Tuscaloosa, AL 35487 (United States); Whittington, W.R.; Francis, D.K. [Department of Mechanical Engineering, Mississippi State University, Starkville, MS 35759 (United States); Rivera, O.G.; Chou, K.; Gong, X. [Department of Mechanical Engineering, University of Alabama, Tuscaloosa, AL 35487 (United States); Butler, T.M. [Department of Metallurgical Engineering, University of Alabama, Tuscaloosa, AL 35487 (United States); Burroughs, J.F. [Geotechnical & Structures Laboratory, US Army ERDC, Vicksburg, MS 39180 (United States)

    2015-08-12

    High rate and quasi-static tensile experiments examined strain rate dependence on flow stress and strain hardening of additive manufactured Ti6Al4V. Variations on strain-hardening coefficient indicate that the rate of thermal softening is greater than strain hardening during plastic deformation. Strain rate sensitivity calculations within the plastic strain regime suggest changes in deformation mechanisms. Fractography revealed cup-and-cone fracture for quasi-static samples and shear mechanisms for high rate samples. As-deposited microstructure consisted of bimodal α+β with the presence of secondary martensitic phase.

  16. Influence of trace boron addition on the directional solidification characteristics of Ti-6Al-4V

    International Nuclear Information System (INIS)

    Srinivasan, Raghavan; Tamirisakandala, Sesh

    2010-01-01

    Trace boron addition to several titanium alloys results in a reduction in the as-cast grain size by an order of magnitude. TiB needles are observed along the prior beta grain boundaries and not the grain interior in these alloys, indicating that TiB needles are not sites for the heterogeneous nucleation of beta grains. This study seeks to understand the influence of the growth rate R on microstructure evolution and grain refinement in Ti-6Al-4V-0.1B alloy using directional solidification experiments and microstructural characterization.

  17. Dry sliding wear behaviour of Al-12Si-4Mg alloy with cerium addition

    International Nuclear Information System (INIS)

    Anasyida, A.S.; Daud, A.R.; Ghazali, M.J.

    2010-01-01

    The purpose of this work is to understand the effect of cerium addition on wear resistance behaviour of as-cast alloys. Al-12Si-4 Mg alloys with 1-5 wt% cerium addition were prepared using the casting technique. A sliding wear test was carried out under applied loads of 10 N, 30 N and 50 N at a fixed sliding speed of 1 m/s using a pin-on-disc configuration. The wear test was conducted in dry conditions at room temperature of ∼25 o C. Detailed analysis of the microstructure, worn surface, collected debris and microhardness was undertaken in order to investigate the differences between the as-cast alloys with different levels of cerium addition. The addition of 1-5 wt% cerium was found to lead to the precipitation of intermetallic phases (Al-Ce), resulting a needle-like structures. Increasing cerium content up to 2 wt% improved both wear resistance and microhardness of as-cast alloys. Addition of more than 2 wt% cerium, however, led to a decrease in microhardness, resulting in lower wear resistance of the alloys. Moderate wear was observed at all loads, with specific wear rates (K') ranging from 6.82 x 10 -5 with 2 wt% Ce at applied load of 50 N to 21.48 x 10 -5 mm 3 /N m without added Ce at an applied load of 10 N. Based on K' ranges, the as-cast alloys exhibited moderate wear regimes, and the mechanism of wear is a combination of abrasion and adhesion. Alloy containing 2 wt% Ce, with the highest hardness and lowest K' value, showed the greatest wear resistance.

  18. As-cast structure refinement of Ti-46Al alloy by hafnium and boron additions

    Directory of Open Access Journals (Sweden)

    Zhang Li

    2009-05-01

    Full Text Available The infl uence of Hf and B on the solidifi cation structure of cast Ti-46Al alloys was investigated. The results show that the coupling effect of Hf and B changes the solidifi cation structure morphology and strongly refi nes the grain size. When the Hf+B contents were increased from 0 + 0.0 to 3 + 0.2, 5 + 0.6 and 7 + 1.0 (in at. %, the solidification structure morphology changed from coarse columnar dendrite to fine columnar dendrite, then to equiaxed dendrite, and further to fi ne near granular grain whilst the average grain size decreased to 20 μm. It is concluded that the columnar dendrite refinement is due to the effect of Hf and B on the decrease of Al diffusion coeffi cient in the melt. The fi ne near granular grain formation is attributed to the combined constitutional supercooling formed by Al and B segregation that is strengthened by Hf and B additions at the solid/liquid interface during solidifi cation, and the TiB2 precipitates acting as heterogeneous nuclei

  19. Effect of CeLa addition on the microstructures and mechanical properties of Al-Cu-Mn-Mg-Fe alloy

    Energy Technology Data Exchange (ETDEWEB)

    Du, Jiandi [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Ding, Dongyan, E-mail: dyding@sjtu.edu.cn [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Xu, Zhou; Zhang, Junchao; Zhang, Wenlong [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Gao, Yongjin; Chen, Guozhen; Chen, Weigao; You, Xiaohua [Huafon NLM Al Co., Ltd, Shanghai 201506 (China); Chen, Renzong; Huang, Yuanwei; Tang, Jinsong [Shanghai Huafon Materials Technology Institute, Shanghai 201203 (China)

    2017-01-15

    Development of high strength lithium battery shell alloy is highly desired for new energy automobile industry. The microstructures and mechanical properties of Al-Cu-Mn-Mg-Fe alloy with different CeLa additions were investigated through optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Rietveld refinement and tensile testing. Experimental results indicate that Al{sub 8}Cu{sub 4}Ce and Al{sub 6}Cu{sub 6}La phases formed due to CeLa addition. Addition of 0.25 wt.% CeLa could promote the formation of denser precipitation of Al{sub 20}Cu{sub 2}Mn{sub 3} and Al{sub 6}(Mn, Fe) phases, which improved the mechanical properties of the alloy at room temperature. However, up to 0.50 wt.% CeLa addition could promote the formation of coarse Al{sub 8}Cu{sub 4}Ce phase, Al{sub 6}Cu{sub 6}La phase and Al{sub 6}(Mn, Fe) phase, which resulted in weakened mechanical properties. - Highlights: •Al-Cu-Mn-Mg-Fe alloys with different CeLa addition were fabricated through casting and rolling. •Al{sub 8}Cu{sub 4}Ce and Al{sub 6}Cu{sub 6}La phases formed after CeLa addition. •Addition of 0.25 wt.% CeLa promoted formation of denser precipitates of Al{sub 20}Cu{sub 2}Mn{sub 3} and Al{sub 6}(Mn, Fe). •Mechanical properties of the alloy was improved after 0.25 wt.% CeLa addition.

  20. Trends in Solidification Grain Size and Morphology for Additive Manufacturing of Ti-6Al-4V

    Science.gov (United States)

    Gockel, Joy; Sheridan, Luke; Narra, Sneha P.; Klingbeil, Nathan W.; Beuth, Jack

    2017-12-01

    Metal additive manufacturing (AM) is used for both prototyping and production of final parts. Therefore, there is a need to predict and control the microstructural size and morphology. Process mapping is an approach that represents AM process outcomes in terms of input variables. In this work, analytical, numerical, and experimental approaches are combined to provide a holistic view of trends in the solidification grain structure of Ti-6Al-4V across a wide range of AM process input variables. The thermal gradient is shown to vary significantly through the depth of the melt pool, which precludes development of fully equiaxed microstructure throughout the depth of the deposit within any practical range of AM process variables. A strategy for grain size control is demonstrated based on the relationship between melt pool size and grain size across multiple deposit geometries, and additional factors affecting grain size are discussed.

  1. Side-by-Side In(OH3 and In2O3 Nanotubes: Synthesis and Optical Properties

    Directory of Open Access Journals (Sweden)

    Tao Xiaojun

    2009-01-01

    Full Text Available Abstract A simple and mild wet-chemical approach was developed for the synthesis of one-dimensional (1D In(OH3 nanostructures. By calcining the 1D In(OH3 nanocrystals in air at 250 °C, 1D In2O3 nanocrystals with the same morphology were obtained. TEM results show that both 1D In(OH3 and 1D In2O3 are composed of uniform nanotube bundles. SAED and XRD patterns indicate that 1D In(OH3 and 1D In2O3 nanostructures are single crystalline and possess the same bcc crystalline structure as the bulk In(OH3 and In2O3, respectively. TGA/DTA analyses of the precursor In(OH3 and the final product In2O3 confirm the existence of CTAB molecules, and its content is about 6%. The optical absorption band edge of 1D In2O3 exhibits an evident blueshift with respect to that of the commercial In2O3 powders, which is caused by the increasing energy gap resulted from decreasing the grain size. A relatively strong and broad purple-blue emission band centered at 440 nm was observed in the room temperature PL spectrum of 1D In2O3 nanotube bundles, which was mainly attributed to the existence of the oxygen vacancies.

  2. Processing simulated high-level liquid waste by heat treatment with addition of TiN and AlN or Al2O3

    International Nuclear Information System (INIS)

    Uno, Masayoshi; Kinoshita, Hajime; Sakai, Etsuro; Ikeda, Akira; Matsumoto, Y.; Yamanaka, Shinsuke

    1999-01-01

    The present study aims to decrease the melting temperature of the oxide phase by the addition of the mixture of TiN and AlN or Al 2 O 3 for reduction of the treatment temperature of super high temperature method. The addition of the mixture of TiN and AlN or Al 2 O 3 with the atomic ratio of Al to Ti of 1:9 caused the melting of both the alloy phase and oxide phase at 1673 K. The measured values of density and hardness for thus obtained oxide phase were same as those for the oxide phase obtained at 1873 K without Al. Thus, above mentioned method is achieved at 1673 K without degradation of the properties of the oxide phase as an waste. (author)

  3. Effect of V or Zr addition on the mechanical properties of the mechanically alloyed Al-8wt%Ti alloys

    International Nuclear Information System (INIS)

    Moon, I.H.; Lee, J.H.; Lee, K.M.; Kim, Y.D.

    1995-01-01

    Mechanical alloying (MA) of Al-Ti alloy, being a solid state process, offers the unique advantage of producing homogeneous and fine dispersions of thermally stable Al 3 Ti phase, where the formation of the fine Al 3 Ti phase by the other method is restricted from the thermodynamic viewpoint. The MA Al-Ti alloys show substantially higher strength than the conventional Al alloys at the elevated temperature due to the presence of Al 3 Ti as well as Al 4 C 3 and Al 2 O 3 , of which the last two phases were introduced during MA process. The addition of V or Zr to Al-Ti alloy was known to decrease the lattice mismatch between the intermetallic compound and the aluminum matrix, and such decrease in lattice mismatching can influence positively the high temperature mechanical strength of the MA Al-Ti by increasing the resistance to dispersoid coarsening at the elevated temperature. In the present study, therefore, the mechanical behavior of the MA Al-Ti-V and Al-Ti-Zr alloys were investigated in order to evaluate the effect of V or Zr addition on the mechanical properties of the MA Al-8Ti alloy at high temperature

  4. The influence of chromium additions on order and ductility in Fe3Al intermetallic

    International Nuclear Information System (INIS)

    Morris, D.G.; Dadras, M.; Morris, M.A.

    1993-01-01

    It has previously been shown that the addition of Cr to the Fe 3 Al alloy can lead to improvements in ductility. Initial interpretations of this effect were based on changes in the fault energies and dislocation configurations, but recently the influence of environmental attack has been invoked. In the present study the role of Cr and other elemental additions on the state of order, dislocation dissociations and configurations, and on ductility has been examined under conditions where environmental attack should not be important. The addition of Cr is shown to have only a minor affect on ordering kinetics, fault energies and dislocation configurations. However, for the alloys generally considered, containing 28% Al, it is shown that the ordered state and microstructure depends sensitively on the precise composition and heat treatments given. In particular, small amounts of solute elements such as B can lead to the appearance of two-phase ordered-disordered microstructures over a wide temperature range, to the appearance of imperfect long range and short range order, and to major changes in the kinetics of ordering and disordering. The mechanical properties achieved are shown to depend critically on the extent and distribution of disorder (the long range order parameter, the extent of short range order, the presence and distribution of thick disordered domain walls) and this factor may explain much of the variability in properties reported between similar alloys. By way of example, the presence of short range order will confine dislocations to well-defined shear planes, concentrating shear and inducing early failure; disordered domain walls will dissociate superdislocations thereby spreading shear homogeneously; the ordered domains/disordered walls morphology will lead to particle-dispersion hardening. (orig.)

  5. The Effect of Mg Addition and Manufacturing Conditions on the Interfacial Reactions between Al and CNT in Al-CNT Pellets

    International Nuclear Information System (INIS)

    Lim, Jung-Kyu; Choi, Soon-Yool; Choe, Kyong-Hwan; Cho, Gue-Serb; Kim, Sang-Sub

    2013-01-01

    In the present study, Al-CNT pellets were investigated to understand the effect of Mg addition and manufacturing conditions on the interfacial reactions between Al and CNTs in Al-CNT pellets. The pellets were heated and held at 700 °C and 800 °C for 2 hours under nitrogen (N_2) atmosphere. To confirm the reactions between Al and CNT in the pellets under different manufacturing conditions, the microstructures were observed by optical microscopy (OM) and field emission scanning electro microscopy (FESEM). And, the composition and reaction phases were analyzed by energy dispersive X-ray spectroscory (EDXS) and X-ray diffractometry (XRD). The presence of oxidation products and Mg on the surface of Al powder in the pellets appeared to prevent the formation of Al_4C_3. But, Al_4C_3 reaction products were increased due to the high temperature of 800 °C, which produced a high amount of reduced aluminium and increased the reaction areas between Al and CNT. The Al-CNT pellets compacted under air atmosphere prohibited the reaction between Al and CNT because of the high amount of oxidation products, such as MgO and MgAl_2O_4.

  6. The Effects of Cr and Al Addition on Transformation and Properties in Low‐Carbon Bainitic Steels

    Directory of Open Access Journals (Sweden)

    Junyu Tian

    2017-01-01

    Full Text Available Three low‐carbon bainitic steels were designed to investigate the effects of Cr and Al addition on bainitic transformation, microstructures, and properties by metallographic method and dilatometry. The results show that compared with the base steel without Cr and Al addition, only Cr addition is effective for improving the strength of low‐carbon bainitic steel by increasing the amount of bainite. However, compared with the base steel, combined addition of Cr and Al has no significant effect on bainitic transformation and properties. In Cr‐bearing steel, Al addition accelerates initial bainitic transformation, but meanwhile reduces the final amount of bainitic transformation due to the formation of a high‐temperature transformation product such as ferrite. Consequently, the composite strengthening effect of Cr and Al addition is not effective compared with individual addition of Cr in low‐carbon bainitic steels. Therefore, in contrast to high‐carbon steels, bainitic transformation in Cr‐bearing low‐carbon bainitic steels can be finished in a short time, and Al should not be added because Al addition would result in lower mechanical properties.

  7. Effects of Al addition and minor elements on oxidation behaviour of FeCr alloys

    International Nuclear Information System (INIS)

    Herbelin, J.M.; Mantel, M.

    1995-01-01

    It is shown that the addition of aluminium is very effective for the high temperature oxidation resistance of FeCr alloys. 1% aluminium produces a continuous protective Al 2 O 3 oxide for FeCr alloy that contains more than 13% of chromium. However this aluminium content is not enough for the high temperature resistance of thin foils and a 5% aluminium content is needed since the substrate plays the role of an aluminium reserve susceptible to oxidation. Impurity elements such as sulphur are detrimental and give rise to scaling of the oxide layer. Active elements such as Y, Ce, La, Zr are therefore necessary to tie up sulphur and increase the life of the alloys. (orig.)

  8. The effects of Re addition to the nanostructure of a Ni-Cr-Al model superalloy

    International Nuclear Information System (INIS)

    Yoon, K.E.; Seidman, D.N.; Noebe, R.D.

    2004-01-01

    Full text: The refractory elements, such as W, Mo, Ta, and Re, have been at the center of focus since the late 1970s for the development of single-crystal turbine-blades, and they have improved significantly the high-temperature properties of Ni-based superalloys. The optimum mechanical properties and operating temperature of single-crystal blades are achieved by increasing the total amounts of refractory elements. In spite of the improvement of mechanical properties of Ni-based superalloys utilizing the addition of refractory elements, their effects on the microstructure of superalloys are mostly unidentified at the subnano- to nanoscale. Rhenium (2 at.%) was added to a model ternary Ni-8.5 at.% Cr-10 at.% Al superalloy to study its effects on the temporal evolution. The temporal evolution of γ' (L1 2 ) precipitates in a Ni-Cr-AI-Re FCC alloy, aged at 1073 K from 0.25 to 264 h, is investigated by transmission-electron and three-dimensional atom-probe (3DAP) microscopies. The coarsening kinetics of γ' precipitates is investigated by measuring the mean radius, number density of precipitates and matrix supersaturation, and compared with Umantsev-Olson's (UO) coarsening theory for multicomponent alloys. The coarsening experiments do not agree with the time dependencies prediction of UO theory. The cluster-diffusion-coagulation mechanism is involved in coarsening, as well as evaporation-condenzation mechanism, and is suggested to generate discrepancy between the experiments and theory. The addition of Re reduces the lattices parameter misfit between the matrix and precipitates. Therefore, unlike other Ni-based superalloys, this Ni-Cr-AI-Re alloy does not undergo the sphere-to-cube morphological transition and maintains the spheroidal morphology of the γ' precipitates for extended aging times. In addition, the γ' precipitates do not align along [100] direction, even at the longest aging time of 264 h. Contrary to a commercial superalloy Rene N6, significant Re

  9. Effect of Mn and AlTiB Addition and Heattreatment on the Microstructures and Mechanical Properties of Al-Si-Fe-Cu-Zr Alloy.

    Science.gov (United States)

    Yoo, Hyo-Sang; Kim, Yong-Ho; Lee, Seong-Hee; Son, Hyeon-Taek

    2018-09-01

    The microstructure and mechanical properties of as-extruded Al-0.1 wt%Si-0.2 wt%Fe- 0.4 wt%Cu-0.04 wt%Zr-xMn-xAlTiB (x = 1.0 wt%) alloys under various annealing processes were investigated and compared. After the as-cast billets were kept at 400 °C for 1 hr, hot extrusion was carried out with a reduction ratio of 38:1. In the case of the as-extruded Al-Si-Fe-Cu-Zr alloy at annealed at 620 °C, large equiaxed grain was observed. When the Mn content is 1.0 wt%, the phase exhibits a skeleton morphology, the phase formation in which Mn participated. Also, the volume fraction of the intermetallic compounds increased with Mn and AlTiB addition. For the Al-0.1Si-0.2Fe-0.4Cu-0.04Zr alloy with Mn and AlTiB addition from 1.0 wt%, the ultimate tensile strength increased from 100.47 to 119.41 to 110.49 MPa. The tensile strength of the as-extruded alloys improved with the addition of Mn and AlTiB due to the formation of Mn and AlTiB-containing intermetallic compounds.

  10. Electric conductivity of low-temperature molten electrolyte KF-AlF3 with additions of LiF and Al2O3

    International Nuclear Information System (INIS)

    Apisarov, A.P.; Kryukovskij, V.A.; Zajkov, Yu.P.; Red'kin, A.A.; Tkacheva, O.Yu.; Khokhlov, V.A.

    2007-01-01

    Electric conductivity of LiF, Al 2 O 3 doped KF-AlF 3 (Cryolite Ratio CR=1.3) molten electrolytes was estimated on the basis of empiric equations. Specific electric conductivity of KF-AlF 3 , KF-AIF 3 -AI 2 O 3 , KF-AlF 3 -LiF, KF-AlF 3 -LiF-Al 2 0 3 molten mixtures was measured in the range 687-797 Deg C. Cells with the pyrolytic boron nitride capillary and parallel molybdena electrodes were applied for the determination of electric conductivity. Comparison of calculated and experimental data of the specific electric conductivity of cryolite-alumina melts confirms that the offered model of the calculation adequate represents temperature and concentration dependencies, and it permits forecasting its change under the introduction of different additives in electrolyte [ru

  11. Derivation of gravity wave intrinsic parameters and vertical wavelength using a single scanning OH(3-1) airglow spectrometer

    Science.gov (United States)

    Wüst, Sabine; Offenwanger, Thomas; Schmidt, Carsten; Bittner, Michael; Jacobi, Christoph; Stober, Gunter; Yee, Jeng-Hwa; Mlynczak, Martin G.; Russell, James M., III

    2018-05-01

    For the first time, we present an approach to derive zonal, meridional, and vertical wavelengths as well as periods of gravity waves based on only one OH* spectrometer, addressing one vibrational-rotational transition. Knowledge of these parameters is a precondition for the calculation of further information, such as the wave group velocity vector.OH(3-1) spectrometer measurements allow the analysis of gravity wave ground-based periods but spatial information cannot necessarily be deduced. We use a scanning spectrometer and harmonic analysis to derive horizontal wavelengths at the mesopause altitude above Oberpfaffenhofen (48.09° N, 11.28° E), Germany for 22 nights in 2015. Based on the approximation of the dispersion relation for gravity waves of low and medium frequencies and additional horizontal wind information, we calculate vertical wavelengths. The mesopause wind measurements nearest to Oberpfaffenhofen are conducted at Collm (51.30° N, 13.02° E), Germany, ca. 380 km northeast of Oberpfaffenhofen, by a meteor radar.In order to compare our results, vertical temperature profiles of TIMED-SABER (thermosphere ionosphere mesosphere energetics dynamics, sounding of the atmosphere using broadband emission radiometry) overpasses are analysed with respect to the dominating vertical wavelength.

  12. Influence of additives on microstructures, mechanical properties and shock-induced reaction characteristics of Al/Ni composites

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Wei; Zhang, Xianfeng, E-mail: lynx@mail.njust.edu.cn; Wu, Yang; He, Yong; Wang, Chuanting; Guo, Lei

    2015-11-05

    Granular composites containing aluminum (Al) and nickel (Ni) are typical structural energetic materials, which possess ideal combination of both mechanical properties and energy release capability. The influence of two additives, namely Teflon (PTFE) and copper (Cu), on mechanical properties and shock-induced chemical reaction (SICR) characteristics of Al/Ni material system has been investigated. Three composites, namely Al/Ni, Al/Ni/PTFE and Al/Ni/Cu with same volumetric ratio of Al powder to Ni powder, were processed by means of static pressing. Scanning electron microscopy was used to study the microstructure of the mentioned three composites. Quasi static compression tests were also conducted to determine the mechanical properties and fracture behavior of the mentioned three composites. It was shown that the additives affected both compressive strength and fracture mode of the three composites. Impact initiation experiments on the mentioned three composites were performed to determine their shock-induced chemical reaction characteristics by considering pressure histories measured in the test chamber. The experimental results showed that the additives had significant effects on critical initiation velocity, reaction rate, reaction efficiency and post-reaction behavior. - Highlights: • .Al/Ni, Al/Ni/PTFE and Al/Ni/Cu were processed by means of static pressing. • .Microstructures, mechanical properties and shock-induced reactions were studied. • .Microstructures affect both compressive strength and fracture mode. • .Impact velocity is an important factor in shock-induced chemical characteristics. • .Each additive has significant effects on energy release behavior.

  13. Influence of additives on microstructures, mechanical properties and shock-induced reaction characteristics of Al/Ni composites

    International Nuclear Information System (INIS)

    Xiong, Wei; Zhang, Xianfeng; Wu, Yang; He, Yong; Wang, Chuanting; Guo, Lei

    2015-01-01

    Granular composites containing aluminum (Al) and nickel (Ni) are typical structural energetic materials, which possess ideal combination of both mechanical properties and energy release capability. The influence of two additives, namely Teflon (PTFE) and copper (Cu), on mechanical properties and shock-induced chemical reaction (SICR) characteristics of Al/Ni material system has been investigated. Three composites, namely Al/Ni, Al/Ni/PTFE and Al/Ni/Cu with same volumetric ratio of Al powder to Ni powder, were processed by means of static pressing. Scanning electron microscopy was used to study the microstructure of the mentioned three composites. Quasi static compression tests were also conducted to determine the mechanical properties and fracture behavior of the mentioned three composites. It was shown that the additives affected both compressive strength and fracture mode of the three composites. Impact initiation experiments on the mentioned three composites were performed to determine their shock-induced chemical reaction characteristics by considering pressure histories measured in the test chamber. The experimental results showed that the additives had significant effects on critical initiation velocity, reaction rate, reaction efficiency and post-reaction behavior. - Highlights: • .Al/Ni, Al/Ni/PTFE and Al/Ni/Cu were processed by means of static pressing. • .Microstructures, mechanical properties and shock-induced reactions were studied. • .Microstructures affect both compressive strength and fracture mode. • .Impact velocity is an important factor in shock-induced chemical characteristics. • .Each additive has significant effects on energy release behavior

  14. Grain refinement of Ca addition in a twin-roll-cast Mg-3Al-1Zn alloy

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Bin, E-mail: jiangbinrong@cqu.edu.cn [National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400030 (China); College of Materials Science and Engineering, Chongqing University, Chongqing 400030 (China); Liu Wenjun [College of Materials Science and Engineering, Chongqing University, Chongqing 400030 (China); Qiu Dong; Zhang Mingxing [Division of Materials, School of Mechanical and Mining Engineering, University of Queensland, St Lucia, QLD 4072 (Australia); Pan Fusheng [National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400030 (China)

    2012-04-16

    Highlights: Black-Right-Pointing-Pointer Grain refinement of Ca addition in a twin-roll-cast Mg-3Al-1Zn alloy was investigated. Black-Right-Pointing-Pointer Addition of 0.08 wt% Ca into Mg melts can significantly reduce the grain size to 30 {mu}m from 100 {mu}m. Black-Right-Pointing-Pointer Al{sub 2}Ca intermetallic particles have high potency to act as heterogeneous nucleation sites for {alpha}-Mg. - Abstract: Addition of 0.08 wt% Ca into AZ31 melts significantly reduces the average grain size of thin strips produced by twin-roll-cast to 30 {mu}m from 100 {mu}m. Like Zr, due to the high chemical activity, the Ca added into the melts reacts with Al and forms Al{sub 2}Ca intermetallic compound. X-ray diffraction result approves the existence of Al{sub 2}Ca in the thin strips, which formed in the melts. Crystallographic examination of relationship between Al{sub 2}Ca and Mg using the edge-to-edge matching model indicates that Al{sub 2}Ca particles are effective inoculants for heterogeneous nucleation of Mg. It is considered that Al{sub 2}Ca is a potential and effective grain refiner for Mg alloys and the grain refinement through addition of Ca in the AZ31 alloy is attributed to the inoculation effect of Al{sub 2}Ca particles formed in the melts.

  15. Effect of Si addition to Al-8Mg alloy on the microstructure and thermo-physical properties of SiCp/Al composites prepared by pressureless infiltration

    International Nuclear Information System (INIS)

    Ren Shubin; He Xinbo; Qu Xuanhui; Humail, Islam S.; Li Yan

    2007-01-01

    Fifty-five volume percentage of SiCp/Al composites were prepared by pressureless infiltration to investigate the effect of Si addition to Al-8Mg alloy from 0 wt% to 18 wt% on the interfacial reaction between Al and SiC and the thermo-physical properties of the prepared composites. TEM and X-ray analysis showed that the degree of interfacial reaction decreased as the Si content increased, and that it ceased at 1273 K when the Si addition to the aluminum was greater than 12 wt%. The Si addition to Al-8Mg alloy reduced the CTE of the composites and increased their thermal conductivity (TC), but Si beyond 12 wt% led to the reduction of TC, though the CTE was lower. This is attributable to the combined action of the Si on the wettability, interfacial reaction and the TC and CTE of the matrix itself

  16. Ostwald ripening of Pb nanocrystalline phase in mechanically milled Al-Pb alloys and the influence of Cu additive

    International Nuclear Information System (INIS)

    Wu, Z.F.; Zeng, M.Q.; Ouyang, L.Z.; Zhang, X.P.; Zhu, M.

    2005-01-01

    The coarsening behavior of nanosized Pb phase in both Al-10%Pb and Al-10%Pb-4.5%Cu alloys has been studied by X-ray diffraction and transmission electron microscopy analysis. The coarsening of Pb nanophase in Al-Pb alloys still follows the classical ripening theory (the LSW theory) and the addition of Cu decreases the coarsening rate of Pb nanophase

  17. Influence of Al addition on phase transformation and thermal stability of nickel silicides on Si(0 0 1)

    International Nuclear Information System (INIS)

    Huang, Shih-Hsien; Twan, Sheng-Chen; Cheng, Shao-Liang; Lee, Tu; Hu, Jung-Chih; Chen, Lien-Tai; Lee, Sheng-Wei

    2014-01-01

    Highlights: ► The presence of Al slows down the Ni 2 Si–NiSi phase transformation but significantly promotes the NiSi 2−x Al x formation. ► The behavior of phase transformation strongly depends on the Al concentration of the initial Ni 1−x Al x alloys. ► The Ni 0.91 Al 0.09 /Si system exhibits remarkably improved thermal stability, even after high temperature annealing for 1000 s. ► The relationship between microstructures, electrical property, and thermal stability of Ni(Al) silicides is discussed. -- Abstract: The influence of Al addition on the phase transformation and thermal stability of Ni silicides on (0 0 1)Si has been systematically investigated. The presence of Al atoms is found to slow down the Ni 2 Si–NiSi phase transformation but significantly promote the NiSi 2−x Al x formation during annealing. The behavior of phase transformation strongly depends on the Al concentration of the initial Ni 1−x Al x alloys. Compared to the Ni 0.95 Pt 0.05 /Si and Ni 0.95 Al 0.05 /Si system, the Ni 0.91 Al 0.09 /Si sample exhibits remarkably enhanced thermal stability, even after high temperature annealing for 1000 s. The relationship between microstructures, electrical property, and thermal stability of Ni silicides is discussed to elucidate the role of Al during the Ni 1−x Al x alloy silicidation. This work demonstrated that thermally stable Ni 1−x Al x alloy silicides would be a promising candidate as source/drain (S/D) contacts in advanced complementary metal–oxide-semiconductor (CMOS) devices

  18. Data on the surface morphology of additively manufactured Ti-6Al-4V implants during processing by plasma electrolytic oxidation

    NARCIS (Netherlands)

    van Hengel, I.A.J. (Ingmar A.J.); M. Riool (Martijn); L.E. Fratila-Apachitei (L.); J. Witte-Bouma (Janneke); E. Farrell (Eric); A.A. Zadpoor (Amir Abbas); S.A.J. Zaat (Sebastiaan); I. Apachitei (I.)

    2017-01-01

    textabstractAdditively manufactured Ti-6Al-4V implants were biofunctionalized using plasma electrolytic oxidation. At various time points during this process scanning electron microscopy imaging was performed to analyze the surface morphology (van Hengel et al., 2017) [1]. This data shows the

  19. Data on the surface morphology of additively manufactured Ti-6Al-4V implants during processing by plasma electrolytic oxidation

    NARCIS (Netherlands)

    van Hengel, I.A.J.; Riool, Martijn; Fratila-Apachitei, E.L.; Witte-Bouma, Janneke; Farrell, Eric; Zadpoor, A.A.; Zaat, Sebastian A.J.; Apachitei, I.

    2017-01-01

    Additively manufactured Ti-6Al-4V implants were biofunctionalized using plasma electrolytic oxidation. At various time points during this process scanning electron microscopy imaging was performed to analyze the surface morphology (van Hengel et al., 2017) [1]. This data shows the changes in

  20. Effect of Zr Additions on Thermal Stability of Al-Cu Precipitates in As-Cast and Cold Worked Samples

    Directory of Open Access Journals (Sweden)

    Kyle Deane

    2018-05-01

    Full Text Available While Zr is frequently added to Al alloys to control grain size with the formation of large (>1 μm primary precipitates, little research has been conducted on the effect of nanoscale Al3Zr precipitates on Al alloys. By comparing the precipitation and corresponding strength evolution between Al-Cu-Zr alloys with different Zr concentrations, the effects of Zr on Al-Cu precipitation with and without primary Al3Zr precipitates can be observed. In the absence of these large precipitates, all Al3Zr phases can be formed, through high temperature aging treatments, as a dispersion of nanoprecipaites inside the Al grains. In this study, Al-Cu-Zr ternary alloys were produced and heat treated to determine whether an increase in the coarsening resistance of Al-Cu precipitate phases would be observed with a distribution of the more thermally stable Al3Zr nanoprecipitates. Generally, properly aged Al-Cu alloys will coarsen when encountering elevated temperatures higher than ~473 K (~200 °C. Diluted Al-Zr alloys (<0.07 at % Zr resist coarsening behavior until the significantly higher temperatures of ~673 K (~400 °C, but are comparatively limited in strength because of a limited solubility of Zr in the Al matrix. Hardness testing and transmission electron microscope (TEM results are discussed, in which it is found that even very small additions of Zr, when properly accounted for during heat treating, produce a finer microstructure and higher strength than in similar Al-Cu binary alloys. No significant change in the thermal stability of strengthening was observed, indicating that the finer precipitate microstructure is resultant from a higher nucleation density, as opposed to a decrease in coarsening behavior.

  1. Effect of the addition of Al-Ti-C master alloy on the microstructure and microhardness of a cast Al-10Mg alloy

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The microstructure and microhardness of a cast Al-10wt%Mg (henceforth Al-l0Mg) alloy with 0.2wt% addition of Al-5Ti-0.25C master alloy were compared with those of a refiner-free alloy of similar chemical composition.It was found that this level of the master alloy addition not only caused an effective grain refinement, but also caused a significant increase in the microhardness of the Al-10Mg alloy.Microchemical analysis revealed that TiC particles existed in the grain center.The relationship between the holding time and grain size was also studied.It shows that the grain refining efficiency is faded observably with the holding time.This is explained in terms of the instability of TiC particles.

  2. Effect of {gamma}` and {gamma} (Ag{sub 2}Al) precipitates on the steady state creep of Al-16wt%Ag alloys with and without Zr addition

    Energy Technology Data Exchange (ETDEWEB)

    Deaf, G.H. [Ain Shams Univ., Cairo (Egypt). Dept. of Physics; Youssef, S.B. [Ain Shams Univ., Cairo (Egypt). Dept. of Physics; Mahmoud, M.A. [Ain Shams Univ., Cairo (Egypt). Dept. of Physics

    1996-11-16

    The steady state creep behaviour of Al-16 wt% Ag and Al-16 wt% Ag-0.1 wt% Zr alloys has been studied at constant load (= 137.2 MPa) and tested at different working temperatures for samples aged at temperatures favouring the formation of {gamma}` and {gamma} precipitates. It was found that addition of Zr to Al-16 wt% Ag alloy accelerates the precipitations {gamma}` and {gamma} due to the formation of the metastable phase Al{sub 3}Zr. For both alloys, two values of activation energy have been obtained as (34 {+-} 0.3) kJ/mol for viscous glide of dislocations due to the existence of {gamma}` precipitates and (68 {+-} 0.3) kJ/mol for grain boundary diffusion due to the existence of {gamma} precipitates. TEM investigations of {gamma}` and {gamma} precipitates confirmed the above-mentioned effect of Zr addition. (orig.)

  3. Effect of Hypoeutectic Boron Additions on the Grain Size and Mechanical Properties of Ti-6Al-4V Manufactured with Powder Bed Electron Beam Additive Manufacturing

    Science.gov (United States)

    Mahbooba, Zaynab; West, Harvey; Harrysson, Ola; Wojcieszynski, Andrzej; Dehoff, Ryan; Nandwana, Peeyush; Horn, Timothy

    2017-03-01

    In additive manufacturing, microstructural control is feasible via processing parameter alteration. However, the window for parameter variation for certain materials, such as Ti-6Al-4V, is limited, and alternative methods must be employed to customize microstructures. Grain refinement and homogenization in cast titanium alloys has been demonstrated through the addition of hypoeutectic concentrations of boron. This work explores the influence of 0.00 wt.%, 0.25 wt.%, 0.50 wt.%, and 1.0 wt.% boron additions on the microstructure and bulk mechanical properties of Ti-6Al-4V samples fabricated in an Arcam A2 electron beam melting (EBM) system with commercial processing parameters for Ti-6Al-4V. Analyses of EBM fabricated Ti-6Al-4V + B indicate that the addition of 0.25-1.0 wt.% boron progressively refines the grain structure, and it improves hardness and elastic modulus. Despite a reduction in size, the β grain structure remained columnar as a result of directional heat transfer during EBM fabrication.

  4. Surface Roughness and Morphology Customization of Additive Manufactured Open Porous Ti6Al4V Structures

    Directory of Open Access Journals (Sweden)

    Martine Wevers

    2013-10-01

    Full Text Available Additive manufacturing (AM is a production method that enables the building of porous structures with a controlled geometry. However, there is a limited control over the final surface of the product. Hence, complementary surface engineering strategies are needed. In this work, design of experiments (DoE was used to customize post AM surface treatment for 3D selective laser melted Ti6Al4V open porous structures for bone tissue engineering. A two-level three-factor full factorial design was employed to assess the individual and interactive effects of the surface treatment duration and the concentration of the chemical etching solution on the final surface roughness and beam thickness of the treated porous structures. It was observed that the concentration of the surface treatment solution was the most important factor influencing roughness reduction. The designed beam thickness decreased the effectiveness of the surface treatment. In this case study, the optimized processing conditions for AM production and the post-AM surface treatment were defined based on the DoE output and were validated experimentally. This allowed the production of customized 3D porous structures with controlled surface roughness and overall morphological properties, which can assist in more controlled evaluation of the effect of surface roughness on various functional properties.

  5. Surface Roughness and Morphology Customization of Additive Manufactured Open Porous Ti6Al4V Structures.

    Science.gov (United States)

    Pyka, Grzegorz; Kerckhofs, Greet; Papantoniou, Ioannis; Speirs, Mathew; Schrooten, Jan; Wevers, Martine

    2013-10-22

    Additive manufacturing (AM) is a production method that enables the building of porous structures with a controlled geometry. However, there is a limited control over the final surface of the product. Hence, complementary surface engineering strategies are needed. In this work, design of experiments (DoE) was used to customize post AM surface treatment for 3D selective laser melted Ti6Al4V open porous structures for bone tissue engineering. A two-level three-factor full factorial design was employed to assess the individual and interactive effects of the surface treatment duration and the concentration of the chemical etching solution on the final surface roughness and beam thickness of the treated porous structures. It was observed that the concentration of the surface treatment solution was the most important factor influencing roughness reduction. The designed beam thickness decreased the effectiveness of the surface treatment. In this case study, the optimized processing conditions for AM production and the post-AM surface treatment were defined based on the DoE output and were validated experimentally. This allowed the production of customized 3D porous structures with controlled surface roughness and overall morphological properties, which can assist in more controlled evaluation of the effect of surface roughness on various functional properties.

  6. Influence of small additions of Sc and Zr on structure and mechanical properties of Al-Zn-Mg-Cu alloy

    International Nuclear Information System (INIS)

    Kajgorodova, L.I.; Sel'nikhina, E.I.; Tkachenko, E.A.; Senatorova, O.G.

    1996-01-01

    A study was made into Sc and Zr addition effects on grain structure formation, supersaturated solid solution decomposition and mechanical properties of Al-7%Zn-2%Mg-1.2%Cu alloy. It is shown that grain structure is determined by volume fraction and distribution character of disperse particles of Al 3 Sc and Al 3 (Sc 1-x Zr x ). The reason for additives influence on decomposition kinetics during natural and artificial ageing are revealed. The structural factors responsible for the enhancement of mechanical properties on alloying are discussed. 17 refs.; 5 figs.; 2 tabs

  7. Effect of Rapid Solidification and Addition of Cu3P on the Mechanical Properties of Hypereutectic Al-Si Alloys

    OpenAIRE

    Suárez-Rosales,Miguel Ángel; Pinto-Segura,Raúl; Palacios-Beas,Elia Guadalupe; Hernández-Herrera,Alfredo; Chávez-Alcalá,José Federico

    2016-01-01

    The combined processes; rapid solidification, addition of Cu3P compound and heat treatments to improve the mechanical properties of the hypereutectic Al-13Si, Al-20Si and Al-20Si-1.5Fe-0.7Mn alloys (in wt. %) was studied. Optical microscopy and scanning electron microscopy were used to characterize the microstructures. The mechanical properties were evaluated by tensile tests. It was found that the cooling rate (20-50°C/s) used to solidify the alloys plus the addition of Cu3P compound favored...

  8. Investigation of thermal, mechanical and magnetic behaviors of the Cu-11%Al alloy with Ag and Mn additions

    International Nuclear Information System (INIS)

    Silva, R.A.G.; Paganotti, A.; Gama, S.; Adorno, A.T.; Carvalho, T.M.; Santos, C.M.A.

    2013-01-01

    The investigation of thermal, mechanical and magnetic behaviors of the Cu-11%Al, Cu-11%Al-3%Ag, Cu-11%Al-10%Mn and Cu-11%Al-10%Mn-3%Ag alloys was made using microhardness measurements, differential scanning calorimetry, X-ray diffractometry, scanning electron microscopy, energy dispersion X-ray spectroscopy and magnetic moment change with applied field measurement. The results indicated that the Mn addition changes the phase stability range, the microhardness values and makes undetectable the eutectoid reaction in annealed Cu-11%Al and Cu-11%Al-3%Ag alloys while the presence of Ag does not modify the phase transformation sequence neither microhardness values of the annealed Cu-11%Al and Cu-11%Al-10%Mn alloys, but it increases the magnetic moment of this latter at about 2.7 times and decreases the rates of eutectoid and peritectoid reactions of the former. - Highlights: ► The microstructure of Cu-Al alloy is modified in the Ag presence. ► (α + γ) phase is stabilized down to room temperature when Ag is added to Cu-Al alloy. ► Ag-rich phase modifies the magnetic characteristics of Cu–Al–Mn alloy.

  9. Remelting of aluminium with the addition of AlTi5B1 and AlTi3C0,15 grain refiners

    Directory of Open Access Journals (Sweden)

    Dobešrek, M.

    2008-04-01

    Full Text Available It was found that concentration of boron in aluminium with the addition of AlTi5B1 grain refiner is decreasing during remelting as a consequence of TiB2 particles settling down due to gravity. TiB2 particles remained in aluminium after four remelts shows lower effect of grain refinement compared to non-remelted samples with the same TiB2 content. It was also found that TiC particles are still present in aluminium with the addition of AlTi3C0,15 grain refiner after four remelts and they probably participate in nucleation of α-Al grains.

  10. The Effect of Nb Addition on the Microstructure and the High-Temperature Strength of Fe3Al Aluminide

    Science.gov (United States)

    Kratochvíl, Petr; Švec, Martin; Král, Robert; Veselý, Jozef; Lukáč, Pavel; Vlasák, Tomáš

    2018-02-01

    The microstructural and high-temperature mechanical properties of Fe-26Al-xNb (x = 3 and 5 at. pct) are compared. The alloys were investigated "as cast" and after hot rolling at 1473 K (1200 °C). Scanning electron microscopes equipped with EDS and EBSD were used for the microstructure and phase identification. The addition of 3 at. pct of Nb into the Fe3Al matrix leads to the formation of C14 λ—Laves phase (Fe,Al)2Nb (LP) particles spread in the Fe3Al matrix, while an eutectic with thin lamellae of LP C14 λ—Laves phase (Fe,Al)2Nb and matrix is also formed in the iron aluminide with 5 at. pct of Nb. The presence of incoherent precipitates is connected with the enhancement of the high-temperature strength and creep resistance.

  11. Crystal structure and stability of LiAlD{sub 4} with TiF{sub 3} additive

    Energy Technology Data Exchange (ETDEWEB)

    Brinks, H.W. [Department of Physics, Institute for Energy Technology, P.O. Box 40, Kjeller NO-2027 (Norway)]. E-mail: hwbrinks@ife.no; Fossdal, A. [Department of Physics, Institute for Energy Technology, P.O. Box 40, Kjeller NO-2027 (Norway); Fonnelop, J.E. [Department of Physics, Institute for Energy Technology, P.O. Box 40, Kjeller NO-2027 (Norway); Hauback, B.C. [Department of Physics, Institute for Energy Technology, P.O. Box 40, Kjeller NO-2027 (Norway)

    2005-07-19

    LiAlD{sub 4} samples with TiF{sub 3} additives have been investigated by synchrotron X-ray diffraction, neutron diffraction and a Sieverts-type apparatus. Directly after ball milling there are no signs of any Ti-containing phases, and the unit-cell of LiAlD{sub 4} and Al give no indication of any solid solutions. Hence it is concluded that the Ti is in an amorphous state directly after ball milling. Furthermore, no LiF was observed in the samples. Based on Sieverts-type measurements the plateau pressure at 80 deg C has been proved to be higher than 85 bar. Samples stored in a glove box are slowly desorbed, and after 6 months for a LiAlD{sub 4} + TiF{sub 3} sample, the reaction to LiD + Al is nearly finished.

  12. Effect of Ge addition on mechanical properties and fracture behavior of Cu-Zr-Al bulk metallic glass

    International Nuclear Information System (INIS)

    Malekan, M.; Shabestari, S.G.; Gholamipour, R.; Seyedein, S.H.

    2009-01-01

    Effect of the addition of a small amount of Ge on mechanical properties and fracture behavior of Cu 50 Zr 43 Al 7 (at.%) bulk metallic glass were studied. The Cu 50 Zr 43 Al 7 alloy has a surprising glass-forming ability (GFA), and the glassy rods up to 4 mm in diameter can be formed. Partial addition of Ge causes the crystalline phases precipitate in the glassy matrix of (Cu 50 Zr 43 Al 7 ) 100-x Ge x (x = 0, 1, 2) rods with a diameter of 4 mm. In uniaxial compression, Cu 50 Zr 43 Al 7 bulk metallic glass exhibit high strength of 1692 MPa and very limited plasticity of 0.05%. When Ge increases from 0 to 2 at.%, the strength decreases, but plastic strain increases about 2.5%. Fracture surface and shear bands of samples were investigated by scanning electron microscopy (SEM).

  13. Effect of boron addition on the magnetic properties of the Fe-Nd-Al alloys prepared by suction casting

    International Nuclear Information System (INIS)

    Bai, Q.; Xu, H.; Tan, X.H.; Zhang, S.Y.

    2007-01-01

    The microstructure and magnetic properties of the Fe-Nd-Al alloys prepared by suction casting with boron addition have been investigated. The increasing boron content in the Fe-Nd-Al alloys significantly increases the intrinsic coercivity ( i H c ) and decreases the proportion of the amorphous phase. The magnetization at the maximum applied field (σ ' s ) of the Fe-Nd-Al-B alloys decreases, while the coercivity increases markedly after annealing. The high intrinsic coercivity is due to the presence of the Nd 2 Fe 14 B phase

  14. Data on the surface morphology of additively manufactured Ti-6Al-4V implants during processing by plasma electrolytic oxidation

    Directory of Open Access Journals (Sweden)

    Ingmar A.J. van Hengel

    2017-08-01

    Full Text Available Additively manufactured Ti-6Al-4V implants were biofunctionalized using plasma electrolytic oxidation. At various time points during this process scanning electron microscopy imaging was performed to analyze the surface morphology (van Hengel et al., 2017 [1]. This data shows the changes in surface morphology during plasma electrolytic oxidation. Data presented in this article are related to the research article “Selective laser melting porous metallic implants with immobilized silver nanoparticles kill and prevent biofilm formation by methicillin-resistant Staphylococcus aureus” (van Hengel et al., 2017 [1].

  15. Spin-glass state in the mixed system (Co1-xFex)2(OH)3Cl on deformed pyrochlore lattice

    International Nuclear Information System (INIS)

    Fujihala, M.; Hagihala, M.; Zheng, X.G.; Kawae, T.

    2009-01-01

    Magnetic interactions in a new geometrically frustrated system (Co 1-x Fe x ) 2 (OH) 3 Cl are investigated using magnetic susceptibility and μSR study. While Co 2 (OH) 3 Cl is ferromagnetic and Fe 2 (OH) 3 Cl antiferromagnetic, the partially substituted series (Co 1-x Fe x ) 2 (OH) 3 Cl show spin-glass behaviours, wherein ferromagnetic interactions prevail for low Fe concentration and antiferromagnetic ones prevail for high Fe concentration. In special, analysis of the AC magnetic susceptibility and ZF-μ + SR for the x=0.5 sample suggest that CoFe(OH) 3 Cl has both features of chemically disordered random spin glass and geometrically frustrated spin glass. It is also the first spin-glass system for the newly found geometric frustration series M 2 (OH) 3 X.

  16. Effect of TiC addition on fracture toughness of Al6061 alloy

    Science.gov (United States)

    Raviraj, M. S.; Sharanprabhu, C. M.; Mohankumar, G. C.

    2018-04-01

    Al 6061 matrix was reinforced with different proportions of TiC particles such as 3wt%, 5wt% and 7wt% and the effect on fracture toughness was studied. Al-TiC metal matrix composites were produced by stir casting method to ensure uniform distribution of the TiC particulates in the Al matrix. LEFM (Linear Elastic Fracture Mechanics) has been used to characterize the fracture toughness using various specimen geometries. The compact tension (CT) specimens with straight through notch were machined as per ASTM E399 specifications. All the specimens were machined to have constant a/W=0.5 and B/W was varied from 0.2 to 0.7. A sharp crack initiation was done at the end of notch by fatigue loading using servo-hydraulic controlled testing machine. Load v/s crack mouth opening displacement (CMOD) data was plotted and stress intensity factor, KQ determined. Critical stress intensity factor KIC was obtained by plotting KQ v/s thickness of specimen data. The fracture toughness of the composites varied between 16-19 MPa√m as compared to 23MPa√m for base alloy Al6061. Composites with 3wt% and 7wt% TiC showed better fracture toughness than 5wt% TiC reinforced Al metal matrix composites.

  17. Structure alterations in Al-Y-based metallic glasses with La and Ni addition

    Energy Technology Data Exchange (ETDEWEB)

    Shi, X. M.; Wang, X. D., E-mail: wangxd@zju.edu.cn, E-mail: jiangjz@zju.edu.cn; Yu, Q.; Cao, Q. P.; Jiang, J. Z., E-mail: wangxd@zju.edu.cn, E-mail: jiangjz@zju.edu.cn [International Center for New-Structured Materials (ICNSM), Laboratory of New-Structured Materials, and School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Zhang, D. X. [State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou 310027 (China); Zhang, J.; Hu, T. D. [Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing (China); Lai, L. H.; Xie, H. L.; Xiao, T. Q. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201203 (China)

    2016-03-21

    The atomic structures of Al{sub 89}Y{sub 11}, Al{sub 90}Y{sub 6.5}La{sub 3.5}, and Al{sub 82.8}Y{sub 6.07}Ni{sub 8}La{sub 3.13} metallic glasses have been studied by using high energy X-ray diffraction, X-ray absorption fine structure combined with the ab initio molecular dynamics and reverse Monte Carlo simulations. It is demonstrated that the partial replacement of Y atoms by La has limited improvement of the glass forming ability (GFA), although La atoms reduce the ordering around Y atoms and also the fractions of icosahedron-like polyhedra centered by Al atoms. In contrast, Ni atoms can significantly improve the GFA, which are inclined to locate in the shell of polyhedra centered by Al, Y, and La atoms, mainly forming Ni-centered icosahedron-like polyhedra to enhance the spatial connectivity between clusters and suppress the crystallization.

  18. Hardening mechanisms of spray formed Al-Zn-Mg-Cu alloys with scandium and other elemental additions

    International Nuclear Information System (INIS)

    Sharma, M.M.; Amateau, M.F.; Eden, T.J.

    2006-01-01

    The hardening mechanisms in spray formed Al-Zn-Mg-Cu alloys with additions of chromium, zinc and scandium were studied. The microstructure of the spray formed alloys was analyzed by transmission electron microscopy. A range of tensile strengths were achieved, and varied based on elemental additions, and second phase particle strengthening. To explain the significantly higher strength in one alloy with scandium, theoretical results due to the yield stress of Al-Zn-Mg-Cu alloys as a function of volume fraction and precipitate particle size, were compared to experimental data. Both the possibilities of coherency and order strengthening are examined. The significant additional hardening achieved in the alloy with scandium is attributed to small ordered particles of Al 3 Sc, which precipitated during aging

  19. Metallurgical evaluation of laser additive manufactured Ti6Al4V components

    CSIR Research Space (South Africa)

    Mutombo, K

    2013-10-01

    Full Text Available of contact between single deposited layer and Ti6Al4V base as well as the tensile properties of the component were evaluated. Powdered metal globularization, size segregation, un-melted or semi-melted particles and chemical surface contamination were revealed...

  20. Influence of cooling rate and cerium addition on rapidly solidified Al-TM alloys

    Czech Academy of Sciences Publication Activity Database

    Michalcová, A.; Vojtěch, D.; Schumacher, G.; Novák, P.; Klementová, Mariana; Šerák, J.; Mudrová, M.; Valdaufová, J.

    2010-01-01

    Roč. 48, č. 1 (2010), s. 1-7 ISSN 0023-432X Institutional research plan: CEZ:AV0Z40320502 Keywords : rapid solidification * Al-TM * microstructure * aluminium Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.471, year: 2010

  1. Fabrication of Copper-Rich Cu-Al Alloy Using the Wire-Arc Additive Manufacturing Process

    Science.gov (United States)

    Dong, Bosheng; Pan, Zengxi; Shen, Chen; Ma, Yan; Li, Huijun

    2017-12-01

    An innovative wire-arc additive manufacturing (WAAM) process is used to fabricate Cu-9 at. pct Al on pure copper plates in situ, through separate feeding of pure Cu and Al wires into a molten pool, which is generated by the gas tungsten arc welding (GTAW) process. After overcoming several processing problems, such as opening the deposition molten pool on the extremely high-thermal conductive copper plate and conducting the Al wire into the molten pool with low feed speed, the copper-rich Cu-Al alloy was successfully produced with constant predesigned Al content above the dilution-affected area. Also, in order to homogenize the as-fabricated material and improve the mechanical properties, two further homogenization heat treatments at 1073 K (800 °C) and 1173 K (900 °C) were applied. The material and mechanical properties of as-fabricated and heat-treated samples were compared and analyzed in detail. With increased annealing temperatures, the content of precipitate phases decreased and the samples showed gradual improvements in both strength and ductility with little variation in microstructures. The present research opened a gate for in-situ fabrication of Cu-Al alloy with target chemical composition and full density using the additive manufacturing process.

  2. Effects of Ce Addition and Isothermal Aging on the Elevated Temperature Tensile Properties of Mechanically Alloyed Al-Ti Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kim, JunKi; Oh, YoungMin; Kim, YongDeog; Kim, SeonJin [Hanyang Univ., Seoul (Korea, Republic of); Kim, ByungChul [KOREA ATOMIC RESEARCH INSTITUTE, TAEJON (Korea, Republic of)

    1997-05-01

    The room and elevated temperature tensile strength of mechanically alloyed Al-8wt%. Ti alloy increased by substituting Ce for Ti up to 25at.%. However, further substitution of Ce for Ti decreased the tensile strength. It was considered to be due to the decrease of volume fraction of Ce contained dispersoid. In the meantime, the decrease of tensile strength due to the isothermal aging was effectively reduced by the addition of Ce at 400 deg. C but not 510 deg. C. The activation energies for the deformation of Al-80wt.%(Ti+Ce)alloys measured at the temperature between 300 deg. C{approx}510 deg. C were about 1.3{approx}1.9 times higher than that for pure Al self-diffusion(142 kJ/mole). Thus, it was considered that the elevated temperature deformation of Al-8wt.%(Ti+Ce)alloys was governed by Orowan mechanism (author). 9 refs. 6 figs.

  3. Addition of iron for the removal of the {beta}-AlFeSi intermetallic by refining of {alpha}-AlFeSi phase in an Al-7.5Si-3.6Cu alloy

    Energy Technology Data Exchange (ETDEWEB)

    Belmares-Perales, S. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon (Mexico); Zaldivar-Cadena, A.A., E-mail: azaldiva70@hotmail.com [Facultad de Ingenieria Civil, Departamento de Ecomateriales y Energia, Instituto de Ingenieria Civil, Av. Fidel Velasquez and Av. Universidad S/N, Cd. Universitaria, San Nicolas de los Garza, N.L. 66450 (Mexico)

    2010-10-25

    Addition of iron into the molten metal for the removal of the {beta}-AlFeSi intermetallic by refining of {alpha}-AlFeSi phase has been studied. Solidification conditions and composition determine the final microstructure and mechanical properties of a casting piece. It is known that increasing the iron content will produce an increasing of the {alpha}-AlFeSi and {beta}-AlFeSi phases. This phenomenon was confirmed with calculations made by Thermo-Calc{sup TM} software and validated with experimental results, however, the technique of iron addition in this study plays an important role on the solidification kinetics of these iron phases because the refining of {alpha}-AlFeSi and removal of {beta}-AlFeSi phases can be improved. Final results showed an improvement in mechanical properties by removal and refining of {beta}-AlFeSi and {alpha}-AlFeSi phases, respectively. This study shows a new method of removal of {beta}-AlFeSi that could be adopted in the aluminum smelting industry in aluminum alloys with a low cooling rate with a secondary dendritic spacing of about 37 {mu}m.

  4. Addition of iron for the removal of the β-AlFeSi intermetallic by refining of α-AlFeSi phase in an Al-7.5Si-3.6Cu alloy

    International Nuclear Information System (INIS)

    Belmares-Perales, S.; Zaldivar-Cadena, A.A.

    2010-01-01

    Addition of iron into the molten metal for the removal of the β-AlFeSi intermetallic by refining of α-AlFeSi phase has been studied. Solidification conditions and composition determine the final microstructure and mechanical properties of a casting piece. It is known that increasing the iron content will produce an increasing of the α-AlFeSi and β-AlFeSi phases. This phenomenon was confirmed with calculations made by Thermo-Calc TM software and validated with experimental results, however, the technique of iron addition in this study plays an important role on the solidification kinetics of these iron phases because the refining of α-AlFeSi and removal of β-AlFeSi phases can be improved. Final results showed an improvement in mechanical properties by removal and refining of β-AlFeSi and α-AlFeSi phases, respectively. This study shows a new method of removal of β-AlFeSi that could be adopted in the aluminum smelting industry in aluminum alloys with a low cooling rate with a secondary dendritic spacing of about 37 μm.

  5. Improved performance of U-Mo dispersion fuel by Si addition in Al matrix.

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Y S; Hofman, G L [Nuclear Engineering Division

    2011-06-01

    The purpose of this report is to collect in one publication and fit together work fragments presented in many conferences in the multi-year time span starting 2002 to the present dealing with the problem of large pore formation in U-Mo/Al dispersion fuel plates first observed in 2002. Hence, this report summarizes the excerpts from papers and reports on how we interpreted the relevant results from out-of-pile and in-pile tests and how this problem was dealt with. This report also provides a refined view to explain in detail and in a quantitative manner the underlying mechanism of the role of silicon in improving the irradiation performance of U-Mo/Al.

  6. Effect of Additions of Ceramic Nanoparticles and Gas-Dynamic Treatment on Al Casting Alloys

    Directory of Open Access Journals (Sweden)

    Konstantin Borodianskiy

    2015-12-01

    Full Text Available In recent years, improving the mechanical properties of metals has become the main challenge in the modern materials and metallurgical industry. An alloying process is usually used to achieve advanced performance of metals. This paper, however, describes an alternative approach. Modification with ceramic nanoparticles, gas-dynamic treatment (GDT and a combined treatment were investigated on a hypoeutectic Al-Si A356 alloy. Microstructural studies revealed the refinement of coarse α-Al grains and the formation of distributed eutectic Si particles. Subsequent testing of the mechanical properties revealed improvement after applying each of the treatments. The best results were obtained after modification with TiCN nanoparticles followed by GDT; the tensile strength and elongation of the A356 alloys increased by 18% and 19%, respectively.

  7. Derivative thermo analysis of the Al-Si cast alloy with addition of rare earths metals

    Directory of Open Access Journals (Sweden)

    M. Krupiński

    2010-01-01

    Full Text Available In this paper the dependence between chemical composition, structure and cooling rate of Al–Si aluminium cast alloy was investigated. For studying of the structure changes the thermo-analysis was carried out, using the UMSA (Universal Metallurgical Simulator and Analyzer device. For structure investigation optical and electron scanning microscopy was used, phase and chemical composition of the Al cast alloy also using qualitative point-wise EDS microanalysis.

  8. Effect of Sn addition on the microstructure and deformation behavior of Mg-3Al alloy

    International Nuclear Information System (INIS)

    Suh, Byeong-Chan; Kim, Jae H.; Bae, Jun Ho; Hwang, Ji Hyun; Shim, Myeong-Shik; Kim, Nack J.

    2017-01-01

    Mg alloys generally suffer from their poor formability at low temperatures due to their strong basal texture and a lack of adequate deformation systems. In the present study, a small amount of Sn was added instead of Zn to Mg-3Al alloy to modify its deformation behavior and improve the stretch formability. Microstructural examinations of the deformed Mg-3Al-1Sn (AT31) alloy by electron backscatter diffraction and transmission electron microscopy show that prismatic slip is quite active during deformation, resulting in much lower r-values and planar anisotropy than the counterpart Mg-3Al-1Zn (AZ31) alloy. Polycrystal plasticity simulation based on visco-plasticity self-consistent (VPSC) model also shows that prismatic slip is the dominant deformation mode in AT31 alloy besides basal slip. As a consequence, AT31 alloy shows a much higher stretch formability than AZ31 alloy. On the other hand, AZ31 alloy shows the development of intense shear bands during stretch forming, and these shear bands act as crack propagating paths, limiting the stretch formability of AZ31 alloy.

  9. Characterization of an Additive Manufactured TiAl Alloy—Steel Joint Produced by Electron Beam Welding

    Directory of Open Access Journals (Sweden)

    Gloria Basile

    2018-01-01

    Full Text Available In this work, the characterization of the assembly of a steel shaft into a γ-TiAl part for turbocharger application, obtained using Electron Beam Welding (EBW technology with a Ni-based filler, was carried out. The Ti-48Al-2Nb-0.7Cr-0.3Si (at % alloy part was produced by Electron Beam Melting (EBM. This additive manufacturing technology allows the production of a lightweight part with complex shapes. The replacement of Nickel-based superalloys with TiAl alloys in turbocharger automotive applications will lead to an improvement of the engine performance and a substantial reduction in fuel consumption and emission. The welding process allows a promising joint to be obtained, not affecting the TiAl microstructure. Nevertheless, it causes the formation of diffusive layers between the Ni-based filler and both steel and TiAl, with the latter side being characterized by a very complex microstructure, which was fully characterized in this paper by means of Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, and nanoindentation. The diffusive interface has a thickness of about 6 µm, and it is composed of several layers. Specifically, from the TiAl alloy side, we find a layer of Ti3Al followed by Al3NiTi2 and AlNi2Ti. Subsequently Ni becomes more predominant, with a first layer characterized by abundant carbide/boride precipitation, and a second layer characterized by Si-enrichment. Then, the chemical composition of the Ni-based filler is gradually reached.

  10. Effects of heat treatment on microstructure and mechanical behaviour of additive manufactured porous Ti6Al4V

    NARCIS (Netherlands)

    Ahmadi, S.M.; Ashok Kumar Jain, R. K.; Zadpoor, A.A.; Ayas, C.; Popovich, V.

    2018-01-01

    Titanium and its alloys such as Ti6Al4V play a major role in the medical industry as bone implants. Nowadays, by the aid of additive manufacturing (AM), it is possible to manufacture porous complex structures which mimic human bone. However, AM parts are near net shape and post processing may be

  11. Effect of Ga2O3 addition on the properties of Y2O3-doped AlN ceramics

    Directory of Open Access Journals (Sweden)

    Shin H.

    2015-01-01

    Full Text Available Effect Ga2O3 addition on the densification and properties of Y2O3-doped AlN ceramics was investigated under the constraint of total sintering additives (Y2O3 and Ga2O3 of 4.5 wt%. Ga was detected in the AlN grain as well as the grain boundary phases. YAlO3 and Y4Al2O9 were observed as the secondary crystalline phases in all of the investigated compositions. As the substitution of Ga2O3 for Y2O3 increased, the quantity of the Y4Al2O9 phase decreased while that of YAlO3 was more or less similar. Neither additional secondary phases was identified, nor was the sinterability inhibited by the Ga2O3 addition; the linear shrinkage and apparent density were above 20 percent and 3.34-3.37 g/cm3, respectively. However, the optical reflectance and the elastic modulus generally decreased whereas the Poisson ratio increased significantly. The dielectric constant and the loss tangent of 4.0Y2O3-0.5Ga2O3-95.5Y2O3 at the resonant frequency of 8.22 GHz were 8.63 and 0.003, respectively.

  12. Uniform Cu2Cl(OH)3 hierarchical microspheres: A novel adsorbent for methylene blue adsorptive removal from aqueous solution

    International Nuclear Information System (INIS)

    Wei, Wei; Gao, Pin; Xie, Jimin; Zong, Sekai; Cui, Henglv; Yue, Xuejie

    2013-01-01

    Using the solution phase method without any surfactants or templates, the hierarchical of Cu 2 Cl(OH) 3 microspheres were synthesized by freeze drying. The size and surface area of the microspheres are ca. 1–2 µm and 76.61 m 2 g −1 , respectively. A possible formation mechanism is presented based on the experimental results. Methylene blue was chosen to investigate the adsorption capacity of the as-prepared adsorbent. The effects of various experimental parameters, such as pH, initial dye concentration, and contact time were investigated. The results showed that the dye removal increased with the increasing in the initial concentration of the dye and also increased in the amount of microspheres used and initial pH. Adsorption data fitted well with the Freundlich adsorption isotherm. The thermodynamic analysis presented the exothermic, spontaneous and more ordered arrangement process. The microspheres could be employed effective for removal of dyes from aqueous solution. - Graphical abstract: The single-crystalline hierarchical Cu 2 Cl(OH) 3 spheres can be prepared for the first time by using a template-free process through freeze-drying. Meanwhile, the hierarchical spheres exhibited high adsorption capacity to methylene blue. Display Omitted - Highlights: • Cu 2 Cl(OH) 3 microspheres were successfully synthesized through a freeze drying process. • A possible formation mechanism of hierarchical microspheres was presented. • The Cu 2 Cl(OH) 3 microspheres have high methylene blue adsorption capacity. • Methylene blue adsorption is a spontaneous and exothermic process. • The adsorption mechanism of microspheres onto dye was proposed in detail

  13. Effect of Si addition on the glass-forming ability of a NiTiZrAlCu alloy

    International Nuclear Information System (INIS)

    Liang, W.Z.; Shen, J.; Sun, J.F.

    2006-01-01

    The effect of Si addition on the glass-forming ability (GFA) of a NiTiZrAlCu alloy was investigated by using differential scanning calorimetry (DSC), differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The maximum diameter of glassy rods increased from 0.5 mm for the Ni 42 Ti 20 Zr 25 Al 8 Cu 5 alloy (the base alloy) to 2.5 mm for the Ni 42 Ti 20 Zr 21.5 Al 8 Cu 5 Si 3.5 alloy and to 3 mm for the Ni 42 Ti 19 Zr 22.5 Al 8 Cu 5 Si 3.5 alloy, when prepared by using the copper mould casting. The GFA of the alloys can be assessed by the reduced glass transition temperature T rg (=T g /T l ) and a newly proposed parameter, δ(=T x /T l - T g ). An addition of a proper amount of Si and a minor substitution of Ti with Zr can enhance the GFA of the base alloy by suppressing the formation of primary Ni(TiZr) and (TiZr)(CuAl) 2 phases and inducing the composition close to eutectic

  14. Effect of Cooling Rate on the Microstructure of Al-Zn Alloys with Addition of Silicon as Nanocomposite

    Directory of Open Access Journals (Sweden)

    S. García-Villarreal

    2013-01-01

    Full Text Available Al-43.5Zn-1.5Si (wt% alloys are widely used as coatings on steel substrates. This kind of coatings is manufactured by hot-dip process, in which Si is added as solid particles or master alloy. The role of Si during formation of the coating is to control the metallurgical reactions between solid steel and liquid Al-Zn-Si alloy initially forming an AlZnFeSi intermetallic layer and next the excess of Si forms intermetallic compounds, which grows over this alloy layer, segregates into the Zn rich interdendritic regions, and solidifies as eutectic reaction product as massive particles with needle like morphology. Therefore, during the experimental procedure is very difficult to control the final morphology and distribution of the silicon phase. The acicular morphology of this phase greatly affects the mechanical properties of the alloy because it acts as stress concentrators. When the coated steel sheet is subjected to bending, the coating presents huge cracks due to the presence of silicon phase. Therefore, the aim of the paper was to propose a new methodology to control the silicon phase through its addition to Al-Zn alloy as nanocomposite and additionally determine the effect of cooling rate (between 10 and 50°Cs−1 on the solidification microstructure and mechanical properties of Al-Zn alloy.

  15. Additional records of vector mosquito diversity collected from Al Khor district of North-eastern Qatar

    Directory of Open Access Journals (Sweden)

    Mahmoud Mohammed Kardousha

    2015-10-01

    Full Text Available Objective: To survey mosquito diversity in the north-eastern area, which includes the most important gas industrial city in Qatar, and to investigate the potential mosquitoes for transmitting diseases. Methods: A study was performed from September 2009 until June 2011 in Al-Khor district of North-eastern Qatar. Five localities were selected for larval collection: Al Khor City (the main city, Al Dhakira, Ras Laffan (gas industrial city, Simsimah and Al Ghuwariyah. The survey was carried out by using different sampling methods and covering all expected natural breeding sites. The larvae were collected, preserved and transferred to the laboratory for identification. Results: Our findings revealed that 10 species of mosquito larvae had been detected from the area and five of them were new records in Qatar. The species encountered were: Ochlerotatus caspius (Pallas 1771, Anopheles stephensi (Liston 1901, Culex quinquefasciatus (Say 1823 (Cx. quinquefasciatus, Culex pipiens biotype molestus (Forskal 1775 (Cx. pipiens, Culex univittatus (Theobald 1901, Culex pusillus (Macquart 1850, Culex tritaeniorhynchus (Giles 1901 (Cx. tritaeniorhynchus, Culex laticinctus (Edwards 1913, Culex sitiens (Weidmann 1828 and Culex perexiguus (Theobald 1901. The new recorded species were Cx. quinquefasciatus, Cx. tritaeniorhynchus, Culex laticinctus, Culex sitiens and Culex perexiguus. The most prevalent type was Cx. pipiens molestus (31.29% and followed by Culex pusillus and Cx. quinquefasciatus which have relatively similar prevalence of 18.72% and 18.52% respectively. Anopheles stephensi was an established vector for malaria. Cx. pipiens molestus and Cx. quinquefasciatus were vectors of West Nile virus and filariasis. Cx. tritaeniorhynchus was established as a vector of Rift Valley virus and Culex univittatus was the main vector of Sindbis virus. Conclusions: The north-eastern area of Qatar harbors is the most important industrial city in the country, which has

  16. Characterization of an Additive Manufactured TiAl Alloy-Steel Joint Produced by Electron Beam Welding.

    Science.gov (United States)

    Basile, Gloria; Baudana, Giorgio; Marchese, Giulio; Lorusso, Massimo; Lombardi, Mariangela; Ugues, Daniele; Fino, Paolo; Biamino, Sara

    2018-01-17

    In this work, the characterization of the assembly of a steel shaft into a γ-TiAl part for turbocharger application, obtained using Electron Beam Welding (EBW) technology with a Ni-based filler, was carried out. The Ti-48Al-2Nb-0.7Cr-0.3Si (at %) alloy part was produced by Electron Beam Melting (EBM). This additive manufacturing technology allows the production of a lightweight part with complex shapes. The replacement of Nickel-based superalloys with TiAl alloys in turbocharger automotive applications will lead to an improvement of the engine performance and a substantial reduction in fuel consumption and emission. The welding process allows a promising joint to be obtained, not affecting the TiAl microstructure. Nevertheless, it causes the formation of diffusive layers between the Ni-based filler and both steel and TiAl, with the latter side being characterized by a very complex microstructure, which was fully characterized in this paper by means of Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, and nanoindentation. The diffusive interface has a thickness of about 6 µm, and it is composed of several layers. Specifically, from the TiAl alloy side, we find a layer of Ti₃Al followed by Al₃NiTi₂ and AlNi₂Ti. Subsequently Ni becomes more predominant, with a first layer characterized by abundant carbide/boride precipitation, and a second layer characterized by Si-enrichment. Then, the chemical composition of the Ni-based filler is gradually reached.

  17. Effect of molybdenum and chromium additions on the mechanical properties of Fe3Al-based alloys

    International Nuclear Information System (INIS)

    Sun Yangshan; Xue Feng; Mei Jianping; Yu Xingquan; Zhang Lining

    1995-01-01

    Iron aluminides based on Fe 3 Al offer excellent oxidation and sulfidation resistance, with lower material cost and density than stainless steels. However, their potential use as structural material has been hindered by limited ductility and a sharp drop in strength above 600 C. Recent development efforts have indicated that adequate engineering ductility of 10--20% and tensile yield strength of as high as 500 MPa can be achieved through control of composition and microstructure. These improved tensile properties make Fe 3 Al-based alloys more competitive against conventional austenic and ferritic steels. The improvement of high temperature mechanical properties has been achieved mainly by alloying processes. Molybdenum has been found to be one of the most important alloying elements for strengthening Fe 3 Al-based alloys at high temperatures. However, the RT(room temperature) ductility decreases with the increase of a molybdenum addition. On the other hand, a chromium addition to Fe 3 Al-based alloys is very efficient for improving RT ductility but not beneficial to yield strength at temperatures to 800 C. The purpose of the present paper is to report the effects of combined additions of molybdenum and chromium on mechanical properties at ambient temperature and high temperature of 600 C

  18. Reduction in secondary dendrite arm spacing in cast eutectic Al-Si piston alloys by cerium addition

    Science.gov (United States)

    Ahmad, R.; Asmael, M. B. A.; Shahizan, N. R.; Gandouz, S.

    2017-01-01

    The effects of Ce on the secondary dendrite arm spacing (SDAS) and mechanical behavior of Al-Si-Cu-Mg alloys were investigated. The reduction of SDAS at different Ce concentrations was evaluated in a directional solidification experiment via computer-aided cooling curve thermal analysis (CA‒CCTA). The results showed that 0.1wt%-1.0wt% Ce addition resulted in a rapid solidification time, Δ t s, and low solidification temperature, Δ T S, whereas 0.1wt% Ce resulted in a fast solidification time, Δ t a-Al, of the α-Al phase. Furthermore, Ce addition refined the SDAS, which was reduced to approximately 36%. The mechanical properties of the alloys with and without Ce were investigated using tensile and hardness tests. The quality index ( Q) and ultimate tensile strength of (UTS) Al-Si-Cu-Mg alloys significantly improved with the addition of 0.1wt% Ce. Moreover, the base alloy hardness was improved with increasing Ce concentration.

  19. The effects of Cu addition on the microstructure and thermal stability of an Al-Mg-Si alloy

    International Nuclear Information System (INIS)

    Man, Jin; Jing, Li; Jie, Shao Guang

    2007-01-01

    The effects of Cu addition on the microstructure and thermal stability of 6082 Al-Mg-Si alloys were investigated. The results show the Q' precipitates are formed when aged at 170 o C for 4 h in 6082 alloy with 0.6% Cu addition. The hardness value of the alloy with 0.6% Cu is always distinctly higher than that of the alloy without Cu during isothermal treatment at 250 o C. Based on the TEM and three-dimensional atom probe (3DAP) results, the thermal stability of the 6082 alloys with Cu addition is discussed with respect to the distribution of Cu

  20. Al-Awadi/Raas-Rothschild Syndrome in a Newborn with Additional Anomalies

    Science.gov (United States)

    Alp, Esma; Atabek, Mehmet Emre; Pirgon, Özgür

    2010-01-01

    Al-Awadi/Raas-Rothschild (AARR) syndrome is a rare phocomelia syndrome characterized by limb/pelvic hypoplasia/aplasia, renal anomalies such as horseshoe and polycystic kidney, and abnormal facial features including cleft palate, hypertelorism and micro-retrognatia. Autosomal recessive inheritance has been proposed for AARR syndrome. In this report a boy affected with AARR syndrome is presented. The previous pregnancy of the mother was terminated because of lower limb agenesis detected at 14th week of gestation. This report emphasizes the importance of recognizing severe pelvic and limb deficiencies in newborns with AARR syndrome and differentiating the syndrome from other multiple malformation syndromes. Fetal ultrasonography at 15th week of gestation is helpful in diagnosing the major extremity anomalies in the fetus. Conflict of interest:None declared. PMID:21274338

  1. Effect of carbon addition on functional and mechnical properties of the Ni3Al phase

    Directory of Open Access Journals (Sweden)

    E. Olejnik

    2012-10-01

    Full Text Available Casting technology was applied and research was carried out on two alloys based on the Ni3Al phase with variable carbon content of 0,2 and 1,25 wt. % C, respectively. Resistance to abrasive wear, friction coefficient and Vickers microhardness were determined. Metallographic studies were conducted to examine the macrostructure and microstructure of the investigated alloys. An increase in resistance to abrasive wear and microhardness of alloy containing 1,25 wt. % C was observed. The coefficient of friction was determined, which for the alloy with increased carbon content was much lower than for the alloy containing 0,2 wt. % C. Structural changes were reported to have some effect on functional and mechanical properties of the examined alloys.

  2. Microstructure and tensile properties of Fe-40 at. pct Al alloys with C, Zr, Hf, and B additions

    Science.gov (United States)

    Gaydosh, D. J.; Draper, S. L.; Nathal, M. V.

    1989-01-01

    The influence of small additions of C, Zr, and Hf, alone or in combination with B, on the microstructure and tensile behavior of substoichiometric FeAl was investigated. Tensile properties were determined from 300 to 1100 K on powder which was consolidated by hot extrusion. All materials possessed some ductility at room temperature, although ternary additions generally reduced ductility compared to the binary alloy. Adding B to the C- and Zr-containing alloys changed the fracture mode from intergranular to transgranular and restored the ductility to approximately 5 percent elongation. Additions of Zr and Hf increased strength up to about 900 K. Fe6Al6Zr and Fe6Al6Hf precipitates, both with identical body-centered tetragonal structures, were identified as the principal second phase in these alloys. Strength decreased steadily as temperature increased above 700 K, as diffusion-assisted mechanisms became operative. Although all alloys had similar strengths at 1100 K, Hf additions significantly improved high-temperature ductility by suppressing cavitation.

  3. The Influence of oxide additives on Ni/Al2O3 catalysts in low temperature methane steam reforming

    International Nuclear Information System (INIS)

    Lazar, Mihaela; Dan, Monica; Mihet, Maria; Almasan, Valer

    2009-01-01

    Hydrogen is industrially produced by methane steam reforming. The process is catalytic and the usual catalyst is based on Ni as the active element. The main problem of this process is its inefficiency. It requires high temperatures at which Ni also favors the formation of graphite, which deactivates the catalysts. Ni has the advantage of being much cheaper than noble metal catalysts, so many researches are done in order to improve the properties of supported Ni catalysts and to decrease the temperature at which the process is energetically efficient. In order to obtain catalysts with high activity and stability, it is essential to maintain the dispersion of the active phase (Ni particles) and the stability of the support. Both properties can be improved by addition of a second oxide to the support. In this paper we present the results obtained in preparation and characterization of Ni/Al 2 O 3 catalysts modified by addition of CeO 2 and La 2 O 3 to alumina support. The following catalysts were prepared by impregnation method: Ni/Al 2 O 3 , Ni/CeO 2 -Al 2 O 3 and Ni/La 2 O 3 -Al 2 O 3 (10 wt.% Ni and 6 wt.% additional oxide). The catalytic surface was characterized by N 2 adsorption - desorption isotherms. The hydrogen - surface bond was characterized by Thermo-Programmed-Desorption (TPD) method. All catalysts were tested in steam reforming reaction of methane in the range of 600 - 700 deg. C, at atmospheric pressure working with CH 4 :H 2 O ratio of 1:3. The modified catalysts showed a better catalytic activity and selectivity for H 2 and CO 2 formation, at lower temperatures than the simple Ni/Al 2 O 3 catalyst. (authors)

  4. Effect of boron addition to the hard magnetic bulk Nd60Fe30Al10 amorphous alloy

    International Nuclear Information System (INIS)

    Kong, H.Z.; Li, Y.; Ding, J.

    2000-01-01

    A detailed study of the effect of boron addition to crystallinity, magnetic properties and thermal properties was carried out for alloys Nd 60-x Fe 30 Al 10 B x with x=0, 1, 3 and 5 produced by copper mold chill casting and melt-spinning. The cast rods of alloys Nd 60-x Fe 30 Al 10 B x were largely amorphous. Remanence up to 0.154 T and coercivity up to 355 kA/m were observed, which were higher than those of the bulk amorphous Nd 60 Fe 30 Al 10 rod of the same diameter. A step in hysteresis loop was observed for the hard magnetic cast rod and ribbon melt-spun at a low speed of 5 m/s of the alloys with boron addition. Consistent increase in the amplitude of the step and magnetic field (H) at which the step was observed as the boron content increased. A single magnetic phase with low coercivity was observed for fully amorphous ribbon melt-spun at high speed of 30 m/s. Full crystallization due to heat treatment resulted in transition of hard magnetic amorphous phase of Nd 55 Fe 30 Al 10 B 5 cast rod to paramagnetic crystalline phases. TEM results of the as-cast rods illustrated the existence of numerous minute Nd-crystallites in amorphous matrix

  5. Mechanical Properties of Additive Manufactured Ti-6Al-4V Using Wire and Powder Based Processes

    International Nuclear Information System (INIS)

    Brandl, Erhard; Palm, Frank; Leyens, Christoph

    2011-01-01

    Since 1986 several techniques of building up geometries layer by layer have been developed and successfully commercialized under numerous trade names. Today, not only prototypes are realized by these techniques, but serial production parts are envisaged. To achieve this progress, the development activities have to focus on the reliability and output material quality. Particularly for aerospace applications, the material quality is an all-dominant factor. In this paper, an electron beam based powder-bed process and a laser based wire-feed process are investigated. Microstructure, chemical composition, static tensile and high cycle fatigue properties of Ti-6Al-4V samples are presented and evaluated from an aerospace application point of view. The static tensile properties resulting from both processes are mostly comparable to properties of cast or wrought material depending on post heat treatment and test direction. Fatigue limits of all samples are similar to those of wrought material. The impurity levels of oxygen, nitrogen, carbon and hydrogen are below the maximum level of plate material (AMS 4911L). The wire-feed process leads to a material with fewer impurities than the powder-bed process.

  6. Tem Observation Of Precipitate Structures In Al-Zn-Mg Alloys With Additions Of Cu/Ag

    Directory of Open Access Journals (Sweden)

    Watanabe K.

    2015-06-01

    Full Text Available Al-Zn-Mg alloy has been known as one of the aluminum alloys with the good age-hardening ability and the high strength among commercial aluminum alloys. The mechanical property of the limited ductility, however, is required to further improvement. In this work, three alloys, which were added Cu or Ag into the Al-Zn-Mg alloy, were prepared to compare the effect of the additional elements on the aging behavior. The content of Ag and Cu were 0.2at.% and the same as, respectively. Ag or Cu added alloy showed higher maximum hardness than base alloy. The particle shape and rod shape precipitates were observed in all alloys peak-aged at 423K. According to addition of Ag or Cu, the number density of the precipitates increased higher than that of base alloy.

  7. Influence of Co addition on the magnetocaloric effect of FeCoSiAlGaPCB amorphous alloys

    OpenAIRE

    Franco García, Victorino; Borrego Moro, Josefa María; Conde Amiano, Alejandro

    2006-01-01

    The FeCoSiAlGaPCB alloys can be prepared as bulk amorphous materials, with outstanding mechanical properties and increased electrical resistivity. These features can be beneficial for their application as a magnetic refrigerant. The influence of Co addition on the magnetic entropy change of the alloy has been studied. This compositional modification displaces the temperature of the peak entropy change closer to room temperature, but reduces the refrigerant capacity of the material...

  8. Accelerated age hardening by plastic deformation in Al-Cu with minor additions of Si and Ge

    International Nuclear Information System (INIS)

    Victoria Castro Riglos, M.; Taquire de la Cruz, M.; Tolley, Alfredo

    2011-01-01

    An extremely fast hardening response with no reduction in peak hardness was obtained in Al-Cu with minor additions of Si and Ge by 8% plastic deformation before artificial aging. The mechanism for the accelerated hardening was determined by detailed characterization with transmission electron microscopy. Plastic deformation was found to enhance the nucleation rate of Si-Ge precipitates, resulting in a higher volume density. Such precipitates catalyzed the formation of θ' precipitates that are responsible for hardening.

  9. Effect of Cu addition on microstructure and corrosion behavior of spray-deposited Zn–30Al alloy

    International Nuclear Information System (INIS)

    Wang Feng; Xiong Baiqing; Zhang Yongan; Liu Hongwei; Li Zhihui; Li Xiwu; Qu Chu

    2012-01-01

    Highlights: ► Zn–30Al–xCu alloys were synthesized by the spray atomization and deposition technique. ► Immersion test and electrochemical measurements have been used to estimate the corrosion rate and the behavior. ► The result indicates that the 1 wt.% Cu addition displays superior corrosion resistance. - Abstract: In this study, one binary Zn–30Al and three ternary Zn–30Al–Cu alloys were synthesized by the spray atomization and deposition technique. The microstructures of the spray-deposited alloys were investigated by means of scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD). Immersion test, potentiodynamic polarization and electrochemical impedance measurements have been used to estimate the corrosion rate and the behavior. The results indicate that the 1 wt.% Cu addition to spray-deposited Zn–30Al alloy does not make significant change in microstructure. However, with the 2, 4 wt.% Cu additions to the alloy, some ε-CuZn 4 compounds with particle or irregular shapes were observed on the grain boundaries in the microstructures. Immersion test and electrochemical measurements confirmed that the 1 wt.% Cu addition displays superior corrosion resistance, whereas the 2, 4 wt.% Cu additions have a baneful effect on the corrosion behavior.

  10. Modeling of Processing-Induced Pore Morphology in an Additively-Manufactured Ti-6Al-4V Alloy.

    Science.gov (United States)

    Kabir, Mohammad Rizviul; Richter, Henning

    2017-02-08

    A selective laser melting (SLM)-based, additively-manufactured Ti-6Al-4V alloy is prone to the accumulation of undesirable defects during layer-by-layer material build-up. Defects in the form of complex-shaped pores are one of the critical issues that need to be considered during the processing of this alloy. Depending on the process parameters, pores with concave or convex boundaries may occur. To exploit the full potential of additively-manufactured Ti-6Al-4V, the interdependency between the process parameters, pore morphology, and resultant mechanical properties, needs to be understood. By incorporating morphological details into numerical models for micromechanical analyses, an in-depth understanding of how these pores interact with the Ti-6Al-4V microstructure can be gained. However, available models for pore analysis lack a realistic description of both the Ti-6Al-4V grain microstructure, and the pore geometry. To overcome this, we propose a comprehensive approach for modeling and discretizing pores with complex geometry, situated in a polycrystalline microstructure. In this approach, the polycrystalline microstructure is modeled by means of Voronoi tessellations, and the complex pore geometry is approximated by strategically combining overlapping spheres of varied sizes. The proposed approach provides an elegant way to model the microstructure of SLM-processed Ti-6Al-4V containing pores or crack-like voids, and makes it possible to investigate the relationship between process parameters, pore morphology, and resultant mechanical properties in a finite-element-based simulation framework.

  11. Modeling of Processing-Induced Pore Morphology in an Additively-Manufactured Ti-6Al-4V Alloy

    Directory of Open Access Journals (Sweden)

    Mohammad Rizviul Kabir

    2017-02-01

    Full Text Available A selective laser melting (SLM-based, additively-manufactured Ti-6Al-4V alloy is prone to the accumulation of undesirable defects during layer-by-layer material build-up. Defects in the form of complex-shaped pores are one of the critical issues that need to be considered during the processing of this alloy. Depending on the process parameters, pores with concave or convex boundaries may occur. To exploit the full potential of additively-manufactured Ti-6Al-4V, the interdependency between the process parameters, pore morphology, and resultant mechanical properties, needs to be understood. By incorporating morphological details into numerical models for micromechanical analyses, an in-depth understanding of how these pores interact with the Ti-6Al-4V microstructure can be gained. However, available models for pore analysis lack a realistic description of both the Ti-6Al-4V grain microstructure, and the pore geometry. To overcome this, we propose a comprehensive approach for modeling and discretizing pores with complex geometry, situated in a polycrystalline microstructure. In this approach, the polycrystalline microstructure is modeled by means of Voronoi tessellations, and the complex pore geometry is approximated by strategically combining overlapping spheres of varied sizes. The proposed approach provides an elegant way to model the microstructure of SLM-processed Ti-6Al-4V containing pores or crack-like voids, and makes it possible to investigate the relationship between process parameters, pore morphology, and resultant mechanical properties in a finite-element-based simulation framework.

  12. Fabricating Superior NiAl Bronze Components through Wire Arc Additive Manufacturing

    Directory of Open Access Journals (Sweden)

    Donghong Ding

    2016-08-01

    Full Text Available Cast nickel aluminum bronze (NAB alloy is widely used for large engineering components in marine applications due to its excellent mechanical properties and corrosion resistance. Casting porosity, as well as coarse microstructure, however, are accompanied by a decrease in mechanical properties of cast NAB components. Although heat treatment, friction stir processing, and fusion welding were implemented to eliminate porosity, improve mechanical properties, and refine the microstructure of as-cast metal, their applications are limited to either surface modification or component repair. Instead of traditional casting techniques, this study focuses on developing NAB components using recently expanded wire arc additive manufacturing (WAAM. Consumable welding wire is melted and deposited layer-by-layer on substrates producing near-net shaped NAB components. Additively-manufactured NAB components without post-processing are fully dense, and exhibit fine microstructure, as well as comparable mechanical properties, to as-cast NAB alloy. The effects of heat input from the welding process and post-weld-heat-treatment (PWHT are shown to give uniform NAB alloys with superior mechanical properties revealing potential marine applications of the WAAM technique in NAB production.

  13. Effect of Y addition on the aging hardening behavior and precipitation evolution of extruded Mg-Al-Zn alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ren, L.B. [Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Chengdu, Sichuan 610031 (China); School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Quan, G.F., E-mail: quangf@home.swjtu.edu.cn [Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Chengdu, Sichuan 610031 (China); School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Zhou, M.Y.; Guo, Y.Y.; Jiang, Z.Z.; Tang, Q. [Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Chengdu, Sichuan 610031 (China); School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China)

    2017-04-06

    Abstract:: The 443 K aging hardening behavior and microstructure evolution of extruded Mg-Al-Zn-Y alloys was investigated in aspects of yttrium (Y) content (0.2–0.8 wt%), holding time (0.5–156 h) and the initial states (as-extruded, solution treated). The grain size, precipitation evolution, phases and chemical composition were characterized by the optical microscope, scanning electron microscope, X-ray diffraction, and energy dispersive spectrometer, respectively. The corresponding mechanical response, including the hardness, uniaxial tensile strength were measured with the Vickers hardness tester and universal testing machine, respectively. The results show that, firstly, there is reversal hardness anisotropy between extrusion direction and normal direction in as-extruded Mg-Al-Zn-Y sheets compared with T5 treated ones. Secondly, the short-term aging softening exist at the beginning of T5 treatment which results in a lower hardness even be close to that of solution treated ones, but not for T6 conditions. Thirdly, the suppression of discontinuous precipitation during the aging treatment become more remarkable with increasing Y addition which because of the reduction of diffusional coherency strain near grain boundary, increasing activation energy for the discontinuous precipitates (β-Mg{sub 17}Al{sub 12} phase, DPs) formation and the dilution region of Al near the Al{sub 2}Y. Serrated GBs can also provide more nucleation sites for DPs and lead to relatively more precipitates during T5 treatment. Moreover, the proportional precipitation strengthening in yield strength and hardness was verified in Mg-Al-Zn-Y alloy during the aging process.

  14. Effect of the AlCr20 Addition on the Microstructure of Secondary AlSi7Mg0.3 Alloy

    Directory of Open Access Journals (Sweden)

    Bolibruchová D.

    2014-06-01

    Full Text Available This paper deals with influence of chrome addition and heat treatment on segregation of iron based phases in the secondary alloy AlSi7Mg0.3 microstructure by chrome and heat treatment. Iron is the most common and harmful impurity in aluminum casting alloys and has long been associated with an increase of casting defects. In generally, iron is associated with the formation of Fe-rich intermetallic phases. It is impossible to remove iron from melt by standard operations, but it is possible to eliminate its negative influence by addition some other elements that affect the segregation of intermetallics in less harmful type or by heat treatment. Realization of experiments and results of analysis show new view on solubility of iron based phases during melt preparation with higher iron content and influence of chrome as iron corrector of iron based phases.

  15. Al2O3 base composites, with addition of NbC and MgO

    International Nuclear Information System (INIS)

    Tonello, Karolina Pereira dos Santos

    2009-01-01

    The worldwide technological advances generate the needs of improved materials with better properties, according to its final purpose. Alumina composites with the addition of carbide particles have become an interesting option for structural applications. This work studies the influence of two commercial aluminas with different particle size and the adding of 1.5 and 6% in volume of niobium carbide and MgO 500 ppm in microstructural and mechanical properties of the composite. Samples were prepared by uniaxial and isostatic pressing and sintering was carried out in a graphite resistance furnace at 1600, 1650, 1700 and 1750 degree C for thirty minutes in Ar atmosphere. The obtained samples were evaluated sintering behavior, density, microstructure and mechanical properties, diffusion tests were realized to verify chemical reactivity between pairs formed by alumina and gray cast iron samples. The differences between aluminas caused some changes on the composites final properties. The composites produced with A16 alumina presented density about 2% higher than those produced with A1000 alumina. Similarly, the hardness also showed higher values. The carbide niobium added to the matrix of alumina delayed the sintering start, with an increase of about 30% in shrinkage initial states, when 6% of NbC was added. Composite with addition of 1,5% of NbC have higher density and hardness, even at lower sintering temperatures. The adding of niobium carbide to the alumina matrix and higher sintering temperatures provided higher density, hardness and fracture toughness to the composite. The best densification and hardness results of were obtained for composites produced with alumina A16 and when 1.5% of NbC was added. (author)

  16. Specific Adaptation of Gas Atomization Processing for Al-Based Alloy Powder for Additive Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Iver [Ames Lab., Ames, IA (United States); Siemon, John [Alcoa Inc., Pittsburgh, PA (United States)

    2017-06-30

    The charge for each gas atomization experiment was provided by Alcoa and consisted of cast blocks cut into 1 inch by 1 inch square rods of the chosen aluminum alloys. The atmosphere in the melting chamber and connected atomization system was evacuated with a mechanical pump prior to backfilling with ultrahigh purity (UHP grade) Ar. The melt was contained in a bottom tapped alumina crucible with an alumina stopper rod to seal the exit while heating to a pouring temperature of 1000 – 1400°C. When the desired superheat was reached, the stopper rod was lifted and melt flowed through pour tube and was atomized with Ar from a 45-22-052-409 gas atomization nozzle (or atomization die), having a jet apex angle of 45 degrees with 22 cylindrical gas jets (each with diameter of 1.32 mm or 0.052 inches) arrayed around the axis of a 10.4 mm central bore. The Ar atomization gas supply regulator pressure was set to produce nozzle manifold pressures for the series of runs at pressures of 250-650 psi. Secondary gas halos of Ar+O2 and He also were added to the interior of the spray chamber at various downstream locations for additional cooling of the atomized droplets, surface passivation, and to prevent coalescence of the resulting powder.

  17. Specific Adaptation of Gas Atomization Processing for Al-Based Alloy Powder for Additive Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Iver [Ames Lab., Ames, IA (United States); Siemon, John [Alcoa, Inc, Pittsburgh, PA (United States)

    2017-06-30

    The initial three atomization attempts resulted in “freeze-outs” within the pour tubes in the pilot-scale system and yielded no powder. Re-evaluation of the alloy liquidus temperatures and melting characteristics, in collaboration with Alcoa, showed further superheat to be necessary to allow the liquid metal to flow through the pour tube to the atomization nozzle. A subsequent smaller run on the experimental atomization system verified these parameters and was successful, as were all successive runs on the larger pilot scale system. One alloy composition froze-out part way through the atomization on both pilot scale runs. SEM images showed needle formation and phase segregations within the microstructure. Analysis of the pour tube freeze-out microstructures showed that large needles formed within the pour tube during the atomization experiment, which eventually blocked the melt stream. Alcoa verified the needle formation in this alloy using theoretical modeling of phase solidification. Sufficient powder of this composition was still generated to allow powder characterization and additive manufacturing trials at Alcoa.

  18. The Influence of Cu Addition on Dispersoid Formation and Mechanical Properties of Al-Mn-Mg 3004 Alloy

    Directory of Open Access Journals (Sweden)

    Zhen Li

    2018-03-01

    Full Text Available The effect of Cu addition on dispersoid precipitation, mechanical properties and creep resistance was investigated in an Al-Mn-Mg 3004 alloy. The addition of Cu promoted dispersoid precipitation by increasing the number density and decreasing the size of dispersoids. Metastable β′-Mg2Si and Q-AlCuMgSi precipitates were observed during the heating process and both could provide favorable nucleation sites for dispersoid precipitation. The addition of Cu improved the thermal stability of dispersoids during a long-term thermal holding at 350 °C for 500 h. Results of mechanical testing show that the addition of Cu remarkably improved the hardness at room temperature, as well as the yield strength and creep resistance at 300 °C, which was mainly attributed to dispersoid strengthening and Cu solid solution strengthening. The yield strength contribution at 300 °C was quantitatively evaluated based on the dispersoid, solid solution and matrix contributions. It was confirmed that dispersoid strengthening is the main strengthening mechanism in the experimental alloys.

  19. The critical effect of Fe on the grain refinement of aluminium via Al-5Ti-1B addition

    International Nuclear Information System (INIS)

    Zhang, Y; Ma, N

    2016-01-01

    The influence of Fe on the nucleation potency of TiB 2 particles was investigated by employing grain refinement of high purity aluminium in this study. Experiment results showed that without Fe, high purity aluminium cannot be refined by 0.8wt.% addition of Al-5Ti-1B. However, high purity aluminium containing 0.08wt.% Fe can be refined effectively by 0.2wt.% addition of Al-5Ti-1B, its grain size was about 206µm in diameter. Fine equiaxed grains of about 153µm in diameter can be obtained for high purity aluminium containing 0.08wt.% Fe and 0.006wt.% Ti. Grain refinement mechanism should include nucleation and dendrite remelting and multiplication. Both nucleation and dendrite remelting and multiplication played essential role on the grain refinement of aluminium. The effect of Fe was linked to increase active nuclei by segregation on TiB 2 surface and then to promote nucleation of α-Al. The performance of Ti was to enhance the dendrite remelting and multiplication by forming small conglomeration zones of Ti atoms concentrated around TiB 2 particles. (paper)

  20. Corrosion resistance of micro-arc oxidation coatings formed on aluminum alloy with addition of Al2O3

    Science.gov (United States)

    Zhang, Y.; Chen, Y.; Du, H. Q.; Zhao, YW

    2018-03-01

    Micro-arc oxidation (MAO) coatings were formed on the aluminum alloy in silicate-based electrolyte without and with the addition of Al2O3. It is showed that the coating produced in 7 g l‑1 Al2O3-containing electrolyte was of the most superior corrosion resistance. Besides, the corrosion properties of the coatings were studied by means of potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) test in both 0.5 M and 1 M NaCl solution. The results proved that the coating is capable to protect the substrate from the corrosion of aggressive Cl‑ in 0.5 M NaCl after 384 h immersion. However, it can not offer protection to the aluminum alloy substrate after 384 h immersion in 1 M NaCl solution. The schematic diagrams illustrate the corrosion process and matched well with the corrosion test results.

  1. Investigation of the HA film deposited on the porous Ti6Al4V alloy prepared via additive manufacturing

    International Nuclear Information System (INIS)

    Surmeneva, M; Chudinova, E; Syrtanov, M; Surmenev, R; Koptioug, A

    2015-01-01

    This study is focused on the use of radio frequency magnetron sputtering to modify the surface of porous Ti6Al4V alloy fabricated via additive manufacturing technology. The hydroxyapatite (HA) coated porous Ti6Al4V alloy was studied in respect with its chemical and phase composition, surface morphology, water contact angle and hysteresis, and surface free energy. Thin nanocrystalline HA film was deposited while its structure with diamond-shaped cells remained unchanged. Hysteresis and water contact angle measurements revealed an effect of the deposited HA films, namely an increased water contact angle and contact angle hysteresis. The increase of the contact angle of the coating-substrate system compared to the uncoated substrate was attributed to the multiscale structure of the resulted surfaces. (paper)

  2. A study of phase transformation in a TiAlNb alloy and the effect of Cr addition

    Energy Technology Data Exchange (ETDEWEB)

    Kesler, Michael S.; Goyel, Sonalika; Rios, Orlando [University of Florida, Materials Science and Engineering, P.O. Box 116400, Gainesville, FL 32611 (United States); Cupid, Damian M. [University of Florida, Materials Science and Engineering, P.O. Box 116400, Gainesville, FL 32611 (United States); Freiberg University of Mining and Technology, Institute of Materials Science, Freiberg (Germany); Seifert, Hans J. [Freiberg University of Mining and Technology, Institute of Materials Science, Freiberg (Germany); Ebrahimi, Fereshteh, E-mail: febra@mse.ufl.edu [University of Florida, Materials Science and Engineering, P.O. Box 116400, Gainesville, FL 32611 (United States)

    2010-05-15

    The phase transformation paths, transformation temperatures and phase equilibria of Ti-45Al-27Nb and Ti-45Al-22Nb-5Cr (at%) alloys were evaluated over a temperature range from 865 deg. C to 1600 deg. C. Both alloys solidified as single {beta}-phase and transformed to {gamma} + {sigma} phases upon slow cooling. The addition of Cr did not affect the {beta} {yields} {gamma} transformation temperature upon slow cooling. In contrast, the temperature, at which the {sigma}-phase formed, was reduced noticeably. Upon heating, the temperature at which the {beta}-phase evolves from the {gamma} + {sigma} microstructure was found to decrease significantly with the addition of Cr. In the ternary alloy the formation of the {gamma}-phase could not be retarded on quenching, however, the substitution of Nb with Cr allowed for the retainment of the {beta}-phase to room temperature. These results are explained by the partitioning of Cr into the {beta}-phase, which in addition to thermodynamic stability reduces the kinetics of transformations at lower temperatures.

  3. A study of phase transformation in a TiAlNb alloy and the effect of Cr addition

    Energy Technology Data Exchange (ETDEWEB)

    Kesler, Michael [University of Florida, Gainesville; Goyel, Sonalika [University of Florida, Gainesville; Rios, Orlando [ORNL; Cupid, Damian M [Freiberg University of Mining and Technology; Seifert, Hans J [Freiberg University of Mining and Technology; Ebrahimi, Fereshteh [University of Florida, Gainesville

    2010-01-01

    The phase transformation paths, transformation temperatures and phase equilibria of Ti-45Al-27Nb and Ti-45Al-22Nb-5Cr (at%) alloys were evaluated over a temperature range from 865 C to 1600 C. Both alloys solidified as single {beta}-phase and transformed to {gamma} + {sigma} phases upon slow cooling. The addition of Cr did not affect the {beta} {yields} {gamma} transformation temperature upon slow cooling. In contrast, the temperature, at which the {sigma}-phase formed, was reduced noticeably. Upon heating, the temperature at which the {beta}-phase evolves from the {gamma} + {sigma} microstructure was found to decrease significantly with the addition of Cr. In the ternary alloy the formation of the {gamma}-phase could not be retarded on quenching, however, the substitution of Nb with Cr allowed for the retainment of the {beta}-phase to room temperature. These results are explained by the partitioning of Cr into the {beta}-phase, which in addition to thermodynamic stability reduces the kinetics of transformations at lower temperatures.

  4. A study of phase transformation in a TiAlNb alloy and the effect of Cr addition

    International Nuclear Information System (INIS)

    Kesler, Michael S.; Goyel, Sonalika; Rios, Orlando; Cupid, Damian M.; Seifert, Hans J.; Ebrahimi, Fereshteh

    2010-01-01

    The phase transformation paths, transformation temperatures and phase equilibria of Ti-45Al-27Nb and Ti-45Al-22Nb-5Cr (at%) alloys were evaluated over a temperature range from 865 deg. C to 1600 deg. C. Both alloys solidified as single β-phase and transformed to γ + σ phases upon slow cooling. The addition of Cr did not affect the β → γ transformation temperature upon slow cooling. In contrast, the temperature, at which the σ-phase formed, was reduced noticeably. Upon heating, the temperature at which the β-phase evolves from the γ + σ microstructure was found to decrease significantly with the addition of Cr. In the ternary alloy the formation of the γ-phase could not be retarded on quenching, however, the substitution of Nb with Cr allowed for the retainment of the β-phase to room temperature. These results are explained by the partitioning of Cr into the β-phase, which in addition to thermodynamic stability reduces the kinetics of transformations at lower temperatures.

  5. Effect of Si addition on glass-forming ability and mechanical properties of Cu-Zr-Al bulk metallic glass

    International Nuclear Information System (INIS)

    Malekan, M.; Shabestari, S.G.; Zhang, W.; Seyedein, S.H.; Gholamipour, R.; Makino, A.; Inoue, A.

    2010-01-01

    Research highlights: The Cu 50 Zr 43 Al 7 alloy has a surprising GFA, and the glassy rods with diameter of 10 mm have been produced in this research. It has not been reported that the Cu-based glassy rods (Cu ≥ 50 at.%) to be produced with the critical diameter greater than 10 mm. The novelty of this research is that the glass formation has been improved and the critical diameter increased to 12 mm for the alloy having x = 1 with the addition of Si. Different criteria are used to evaluate the influence of Si content on the GFA, and the possible mechanisms involved in the achievement of this GFA are also discussed. - Abstract: The effect of Si addition on the glass-forming ability (GFA) and mechanical properties of (Cu 50 Zr 43 Al 7 ) 100-x Si x (x = 0, 0.5, 1, 1.5 and 2 at.%) alloys were investigated. The GFA of Cu 50 Zr 43 Al 7 alloy is improved by addition of a small amount of Si, and the critical diameter for glass formation increases from 10 mm for the alloy with x = 0-12 mm for the alloy with x = 1 when prepared using copper mold casting. Different criteria are used to evaluate the influence of Si content on the GFA, and the possible mechanisms involved in the achievement of this GFA are also discussed. In the uniaxial compression, the bulk glassy alloys exhibit a limited plastic strain of less than 1%, but the compressive fracture strength and Young's modulus were obtained in high values of 1969-2129 MPa and 101-144 GPa, respectively. Fracture surface and shear bands of samples were studied by using scanning electron microscopy (SEM).

  6. The effect of boron additions on irradiation-induced order changes in Ni3Al intermetallic compounds

    International Nuclear Information System (INIS)

    Njah, N.; Gilbon, D.; Dimitrov, O.

    1995-01-01

    The effects of boron additions (0.1 wt%) on the kinetics of atomic order changes in a Ni 76 Al 24 intermetallic compound, under 1 MeV electron irradiation, were investigated at temperatures of 293 K and 410 K and displacement rates of 0.09 x 10 -3 to 4.7 x 10 -3 dpa.s -1 . In these irradiation conditions, a state of residual order was obtained for long irradiation times, characterized by a steady state order parameter S∞; it corresponds to a competition between two opposite features: irradiation disordering and thermal reordering enhanced by irradiation. Boron additions did not affect the efficiency of irradiation-induced disordering: the disordering cross-section (or, equivalently, the number of replacements per displacement var-epsilon) were comparable with and without a boron addition. By contrast, the S∞ values at 293 K were much lower in the alloy containing boron. Since boron does not change the disordering rate, the large difference between the values obtained in undoped and in boron-doped alloys shows that the reordering rate is strongly reduced by the presence of boron. Thus, boron modifies the mobility of the defects responsible for the irradiation-enhanced diffusion. The data on dislocation-loop size and the reordering kinetics suggest that vacancies are trapped by boron at low temperatures and immobilized, probably by the formation of a boron-vacancy complex. The effect becomes weaker at higher displacement rates and higher temperatures, probably due to the boron-vacancy complexes becoming unstable. It is proposed that two different reordering mechanisms may be operative at 293 K, according to the presence of boron: reordering is promoted by vacancy migration in the Ni 76 Al 24 alloy, whereas in the Ni 76 Al 24 (0.1 wt%B) alloy, it is promoted by the migration of split-interstitials or/and of low-mobility vacancy-boron complexes

  7. MICROSTRUCTURE AND TENSILE PROPERTIES OF Fe3Al-BASED ALLOYS WITH VC AND TiC ADDITIONS

    Institute of Scientific and Technical Information of China (English)

    W.L.Xu; Y.S.Sun; S.S.Ding

    2001-01-01

    Microstructure and tensile properties of Fe3Al-based alloys with additions of TiC andVC particles have been investigated.Results show that the formation of TiC particlesresults in the refinement of the macrostructure of as-cast ingots.Although the additionof VC particles does not cause significant change of the as-cast microstructure,themicrostructure of the alloy after hot-working and recrystallization has been found tobe refined.The formation of both VC and TiC particles results in the increase of yieldstrength,especially at high temperature of 600℃.

  8. Determination of Process Parameters for High-Density, Ti-6Al-4V Parts Using Additive Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Kamath, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-08-10

    In our earlier work, we described an approach for determining the process parameters that re- sult in high-density parts manufactured using the additive-manufacturing process of selective laser melting (SLM). Our approach, which combines simple simulations and experiments, was demon- strated using 316L stainless steel. We have also used the approach successfully for several other materials. This short note summarizes the results of our work in determining process parameters for Ti-6Al-4V using a Concept Laser M2 system.

  9. Effects of heat treatment on microstructure and mechanical behaviour of additive manufactured porous Ti6Al4V

    Science.gov (United States)

    Ahmadi, S. M.; Jain, R. K. Ashok Kumar; Zadpoor, A. A.; Ayas, C.; Popovich, V. A.

    2017-12-01

    Titanium and its alloys such as Ti6Al4V play a major role in the medical industry as bone implants. Nowadays, by the aid of additive manufacturing (AM), it is possible to manufacture porous complex structures which mimic human bone. However, AM parts are near net shape and post processing may be needed to improve their mechanical properties. For instance, AM Ti6Al4V samples may be brittle and incapable of withstanding dynamic mechanical loads due to their martensitic microstructure. The aim of this study was to apply two different heat treatment regimes (below and above β-transus) to investigate their effects on the microstructure and mechanical properties of porous Ti6Al4V specimens. After heat treatment, fine acicular α‧ martensitic microstructure was transformed to a mixture of α and β phases. The ductility of the heat-treated specimens, as well as some mechanical properties such as hardness, plateau stress, and first maximum stress changed while the density and elastic gradient of the porous structure remained unchanged.

  10. Effect of temperature and electrolyte concentration on the surface charge properties of fe(oh)3

    International Nuclear Information System (INIS)

    Irshad, M.

    2014-01-01

    Amorphous iron hydroxide was fabricated in the laboratory by precipitation technique. Salt addition and fast titration methods were employed for the determination of zero point charge. The present study is mainly focused on the surface charge, PZC determination from the potentiometric titration data in the temperature range 293 - 323 K and to calculate the thermodynamic parameters during the exchange of surface H+/OH- ions. The PZC of the solid was decreased with increasing the temperature of electrolytic solution. The Standard thermodynamic parameters such as delta H and delta S were also determined from Berube and DeBruyn equation, which showed the endothermic nature of potential determining ion H+/OH- ions. Further, their freedom in the double layer has lost on account of the electrostatic force of interaction. The positive delta G degree values are suggesting the nonspontaneous transferring reactions of H+ and OH- from the bulk solution to the interfacial region. (author)

  11. Co-existence of long-range order and spin fluctuation in a new geometric frustration series M2(OH)3Cl

    International Nuclear Information System (INIS)

    Zheng, X.G.; Hagihala, Masato; Toriyi, Takato

    2007-01-01

    Recently, we observed the co-existence of a long-range magnetic order and spin fluctuation in a clean compound of clinoatacamite, Cu 2 (OH) 3 Cl (PRL95 (2005) 057201). The present work reports magnetic studies on other compounds of this transition metal series M 2 (OH) 3 Cl, where M represents three-dimensional (3D)-electron magnetic ions of Co 2+ , Fe 2+ , etc., respectively. The present study shows that this co-existence is a common feature of the M 2 Cl(OH) 3 series, no matter whether it is anti-ferromagnetic, as in the case of Fe 2 (OH) 3 Cl (T N =15 K), or ferromagnetic, as in the case of Co 2 (OH) 3 Cl (T C =10.5 K). These compounds show a 3D network of corner-sharing tetrahedrons for the magnetic ions. The tetrahedron is slightly tilted with roughly 10% longer distance between the M-M bonded by Cl than those bonded by O and this distortion is suspected to be responsible for the partial order. This research suggests that the transition metal hydroxyhalide M 2 Cl(OH) 3 series are new geometric frustration system on tetrahedral lattice for d-electron spins

  12. Additive manufacturing of Ti-6Al-4V components by shaped metal deposition: Microstructure and mechanical properties

    International Nuclear Information System (INIS)

    Baufeld, Bernd; Biest, Omer Van der; Gault, Rosemary

    2010-01-01

    Shaped metal deposition (SMD) is a relatively new technology of additive manufacturing, which creates near-net shaped components by additive manufacture utilizing tungsten inert gas welding. Especially for Ti alloys, which are difficult to shape by traditional methods and for which the loss of material during machining is also very costly, SMD has great advantages. In the case of Ti-6Al-4V the dense SMD components exhibit large, columnar prior β grains, with a Widmanstaetten α/β microstructure. These prior β grains are slightly tilted in a direction following the temperature field resulting from the moving welding torch. The ultimate tensile strength is between 929 and 1014 MPa, depending on orientation and location of the tensile specimens. Tensile testing vertically to the deposition layers exhibits a strain at failure of 16 ± 3%, while testing parallel to the layers gives a lower value of about 9%.

  13. Development ceramic composites based on Al2O3, SiO2 and IG-017 additive

    Science.gov (United States)

    Kurovics, E.; Shmakova, A.; Kanev, B.; Gömze, L. A.

    2017-02-01

    Based on high purity alumina and quartz powders and IG-017 bio-original additives the authors have developed new ceramic composite materials for different industrial purposes. The main goal was to fine a material and morphological structures of high performance ceramic composites as frames for development complex materials for extreme consumptions in the future. For this the mixed powders of Al2O3 , SiO2 and IG-017 bio-original additive were uniaxially pressed at different compaction pressures into disc shapes and were sintered in electric kiln under air (1) and nitrogrn (2) atmosphere. The grain size distributions of the raw materials were determined by laser granulometry. There thermo-physical properties were also determined by derivatography. The prepared and sintered specimens were tested on geometrical sizes, microstructure and morphology by scanning electron microscopy, porosity and water absorption. In this work the authors present the results of their research and investigation.

  14. Optimization of heat treatment parameters for additive manufacturing and gravity casting AlSi10Mg alloy

    Science.gov (United States)

    Girelli, L.; Tocci, M.; Montesano, L.; Gelfi, M.; Pola, A.

    2017-11-01

    Additive manufacturing of metals is a production process developed in the last few years to realize net shape components with complex geometry and high performance. AlSi10Mg is one of the most widely used aluminium alloys, both in this field and in conventional foundry processes, for its significant mechanical properties combined with good corrosion resistance. In this paper the effect of heat treatment on AlSi10Mg alloy was investigated. Solution and ageing treatments were carried out with different temperatures and times on samples obtained by direct metal laser sintering and gravity casting in order to compare their performance. Microstructural analyses and hardness tests were performed to investigate the effectiveness of the heat treatment. The results were correlated to the sample microstructure and porosity, analysed by means of optical microscopy and density measurements. It was found that, in the additive manufactured samples, the heat treatment can reduce significantly the performance of the alloy also because of the increase of porosity due to entrapped gas during the deposition technique and that the higher the solution temperature the higher the increase of such defects. A so remarkable effect was not found in the conventional cast alloy.

  15. The Influence of Nickel and Tin Additives on the Microstructural and Mechanical Properties of Al-Zn-Mg-Cu Alloys

    Directory of Open Access Journals (Sweden)

    Haider T. Naeem

    2014-01-01

    Full Text Available The effects of nickel and nickel combined tin additions on mechanical properties and microstructural evolutions of aluminum-zinc-magnesium-copper alloys were investigated. Aluminum alloys containing Ni and Sn additives were homogenized at different temperatures conditions and then aged at 120°C for 24 h (T6 and retrogressed at 180°C for 30 min and then reaged at 120°C for 24 h (RRA. Comparison of the ultimate tensile strength (UTS of as-quenched Al-Zn-Mg-Cu-Ni and Al-Zn-Mg-Cu-Ni-Sn alloys with that of similar alloys which underwent aging treatment at T6 temper showed that gains in tensile strengths by 385 MPa and 370 MPa were attained, respectively. These improvements are attributed to the precipitation hardening effects of the alloying element within the base alloy and the formation of nickel/tin-rich dispersoid compounds. These intermetallic compounds retard the grain growth, lead to grain refinement, and result in further strengthening effects. The outcomes of the retrogression and reaging processes which were carried on aluminum alloys indicate that the mechanical strength and Vickers hardness have been enhanced much better than under the aging at T6 temper.

  16. Nickel electroplating on copper pre-activated Al alloy in the electrolyte containing PEG1000 as an additive

    Science.gov (United States)

    Guan, Jie; Wang, Jinwei; Zhang, Dawei

    2018-06-01

    Ni coatings are prepared on Cu-pretreated anodic Al alloy by electroplating technique in environment-friendly electrolytes with PEG1000 as an additive. Some defects like pores, cracks and even uncovered areas are observed for the sample of the Cu-pretreated anodic Al alloy, and these defects seem to be remedied with the following Ni electroplating as observed from their SEM images; while the covering effect of Ni onto the Cu layer is rather limited as judged by their corrosion current data of polarization test. After adding PEG1000 in the Ni electroplating electrolyte, the obtained coating surfaces are seen smoother and thicker; and most of the tiny particles are seen closely packed together with some bigger particles on them. The diffusion of nickel particles into copper layer are confirmed by the line and mapping mode of EDS element analysis for the Ni-Cu composite coating. Their much lower corrosion current density ( I corr) and higher micro-hardness support the fact that the addition of PEG1000 in Ni plating electrolyte has a function of promoting the refinement of Ni particles and the formation of more compacter, thicker and smoother Ni-Cu composite coating.

  17. Sintering of Si C by hot-pressing with addition of Al2O3 and concentrate of rare earths

    International Nuclear Information System (INIS)

    Hwang, M.K.; Silva, C.R.M.

    2004-01-01

    Silicon carbide (SiC) has essentially covalent bonds (∼88%). The high covalency bond is responsible for the good mechanical properties, although it induces a low self diffusion coefficient, making densification more difficult. For a successful densification is necessary to apply pressure on the samples, and/or the addition of sintering additives, which improves the densification. In this SiC samples with alumina (Al2O3) and concentrate of rare earth (CRE) addition were sintered by hot pressing in argon atmospheric at 20 MPa of pressure, heating rate of 20 deg C/min up to 1800 deg C and a dwell time of 1 h. Initially the CRE was calcined at 1000 deg C during 1 h. After that, three mixtures were prepared with distinct concentrations in high energy mill and the samples were sintered. The aim of this work is to improve SiC densification by the liquid phase formation during sintering owing to the additives reactions between itself. The pressure intensify the driving force for densification, taking the liquid phase to drain easier through the grain boundaries, making possible best accommodation and rearrangement of the grains. The application of the pressure on the samples during sintering contributes to improve densification and becomes possible sintering in lower temperature than conventional one. The phases of the sintered samples were analyzed by X-ray diffraction and the morphology were verified by scanning electron microscopy. (author)

  18. Superplasticity behaviors of Al-Zn-Mg-Zr cold-rolled alloy sheet with minor Sc addition

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, H. [School of Materials Science and Engineering, Central South University (Light Alloy Research Institute, Central South University), Changsha 410083 (China); Nonferrous Metal Oriented Advanced Structural Materials and Manufacturing Cooperative Innovation Center, Changsha 410083 (China); Pan, Q.L., E-mail: pql2016@126.com [School of Materials Science and Engineering, Central South University (Light Alloy Research Institute, Central South University), Changsha 410083 (China); Nonferrous Metal Oriented Advanced Structural Materials and Manufacturing Cooperative Innovation Center, Changsha 410083 (China); Yu, X.H.; Huang, X.; Sun, X.; Wang, X.D.; Li, M.J.; Yin, Z.M. [School of Materials Science and Engineering, Central South University (Light Alloy Research Institute, Central South University), Changsha 410083 (China); Nonferrous Metal Oriented Advanced Structural Materials and Manufacturing Cooperative Innovation Center, Changsha 410083 (China)

    2016-10-31

    A refined microstructure of Al-Zn-Mg-Sc-Zr alloy sheet was produced by simple hot and cold rolling to an average grain size of 3 µm. Experiments were completed in electro-fluid servo-fatigue tester and results were investigated by means of optical microscope (OM), scanning electron microscopy (SEM) and transmission electron microscope (TEM). Superplastic deformation was conducted and superplastic ductility of ≥200% was achieved at a testing temperature range from 425 ºC to 500 ºC and relative high strain rate range of 1×10{sup −3} s{sup −1}~1×10{sup −1} s{sup −1}. The maximum elongation of 539% was obtained at 500 ºC and 1×10{sup −2} s{sup −1}. In addition, the scanning electron microscopy (SEM) and transmission electron microscope (TEM) analyses showed that the presence of Al{sub 3} (Sc, Zr) particles in pinning grain boundaries and dislocations had a great influence on the superplastic deformation. The analyses of superplastic test data calculated out the coherent strain rates sensitivity parameter of 0.43 and the average activation energy of 143.762 kJ/mol. The data interpreted that the dominant deformation mechanism was grain boundary sliding controlled by lattice self-diffusion.

  19. Additive manufacturing of a functionally graded material from Ti-6Al-4V to Invar: Experimental characterization and thermodynamic calculations

    International Nuclear Information System (INIS)

    Bobbio, Lourdes D.; Otis, Richard A.; Borgonia, John Paul; Dillon, R. Peter; Shapiro, Andrew A.; Liu, Zi-Kui; Beese, Allison M.

    2017-01-01

    In functionally graded materials (FGMs), the elemental composition, or structure, within a component varies gradually as a function of position, allowing for the gradual transition from one alloy to another, and the local tailoring of properties. One method for fabricating FGMs with varying elemental composition is through layer-by-layer directed energy deposition additive manufacturing. This work combines experimental characterization and computational analysis to investigate a material graded from Ti-6Al-4V to Invar 36 (64 wt% Fe, 36 wt% Ni). The microstructure, composition, phases, and microhardness were determined as a function of position within the FGM. During the fabrication process, detrimental phases associated with the compositional blending of the Ti-6Al-4V and Invar formed, leading to cracking in the final deposited part. Intermetallic phases (FeTi, Fe_2Ti, Ni_3Ti, and NiTi_2) were experimentally identified to occur throughout the gradient region, and were considered as the reason that the FGM cracked during fabrication. CALPHAD (CALculation of PHase Diagrams) thermodynamic calculations were used concurrently to predict phases that would form during the manufacturing process and were compared to the experimental results. The experimental-computational approach described herein for characterizing FGMs can be used to improve the understanding and design of other FGMs.

  20. Influence of Li₂Sb Additions on Microstructure and Mechanical Properties of Al-20Mg₂Si Alloy.

    Science.gov (United States)

    Yu, Hong-Chen; Wang, Hui-Yuan; Chen, Lei; Zha, Min; Wang, Cheng; Li, Chao; Jiang, Qi-Chuan

    2016-03-29

    It is found that Li₂Sb compound can act as the nucleus of primary Mg₂Si during solidification, by which the particle size of primary Mg₂Si decreased from ~300 to ~15-25 μm. Owing to the synergistic effect of the Li₂Sb nucleus and adsorption-poisoning of Li atoms, the effect of complex modification of Li-Sb on primary Mg₂Si was better than that of single modification of Li or Sb. When Li-Sb content increased from 0 to 0.2 and further to 0.5 wt.%, coarse dendrite changed to defective truncated octahedron and finally to perfect truncated octahedral shape. With the addition of Li and Sb, ultimate compression strength (UCS) of Al-20Mg₂Si alloys increased from ~283 to ~341 MPa and the yield strength (YS) at 0.2% offset increased from ~112 to ~179 MPa while almost no change was seen in the uniform elongation. Our study offers a simple method to control the morphology and size of primary Mg₂Si, which will inspire developing new Al-Mg-Si alloys with improved mechanical properties.

  1. Effect of Nitric and Oxalic Acid Addition on Hard Anodizing of AlCu4Mg1 in Sulphuric Acid

    Directory of Open Access Journals (Sweden)

    Maximilian Sieber

    2018-02-01

    Full Text Available The anodic oxidation process is an established means for the improvement of the wear and corrosion resistance of high-strength aluminum alloys. For high-strength aluminum-copper alloys of the 2000 series, both the current efficiency of the anodic oxidation process and the hardness of the oxide coatings are significantly reduced in comparison to unalloyed substrates. With regard to this challenge, recent investigations have indicated a beneficial effect of nitric acid addition to the commonly used sulphuric acid electrolytes both in terms of coating properties and process efficiency. The present work investigates the anodic oxidation of the AlCu4Mg1 alloy in a sulphuric acid electrolyte with additions of nitric acid as well as oxalic acid as a reference in a full-factorial design of experiments (DOE. The effect of the electrolyte composition on process efficiency, coating thickness and hardness is established by using response functions. A mechanism for the participation of the nitric acid additive during the oxide formation is proposed. The statistical significance of the results is assessed by an analysis of variance (ANOVA. Eventually, scratch testing is applied in order to evaluate the failure mechanisms and the abrasion resistance of the obtained conversion coatings.

  2. Numerical investigation of FAST powder consolidation of Al2O3 and additive free β-SiC

    International Nuclear Information System (INIS)

    Allen, J B; Cornwell, C F; Carlson, T; Marsh, C P

    2015-01-01

    In this work we examine ceramic synthesis through powder consolidation and the field assisted sintering technique. In particular, we investigate the sintering of Al 2 O 3 and additive free β−SiC from both an experimental and numerical perspective. For the numerical model, the continuum theory of sintering model is employed, and the densification mechanisms corresponding to power law creep and grain boundary diffusion are considered. Experiments are used for comparison and validation purposes. The results indicate that in general, the densification kinetics simulated by the numerical model compare favorably with the experimental results. Parametric studies involving initial grain size, heating rate, and applied stress are also examined using the numerical model, and confirm many of the expected results from previous research, including increased densification due to higher heating rates, smaller grain sizes, and increased applied loading conditions. (paper)

  3. Experimental analysis on semi-finishing machining of Ti6Al4V additively manufactured by direct melting laser sintering

    Science.gov (United States)

    Imbrogno, Stano; Bordin, Alberto; Bruschi, Stefania; Umbrello, Domenico

    2016-10-01

    The Additive Manufacturing (AM) techniques are particularly appealing especially for titanium aerospace and biomedical components because they permit to achieve a strong reduction of the buy-to-fly ratio. However, finishing machining operations are often necessary to reduce the uneven surface roughness and geometrics because of local missing accuracy. This work shows the influence of the cutting parameters, cutting speed and feed rate, on the cutting forces as well as on the thermal field observed in the cutting zone, during a turning operation carried out on bars made of Ti6Al4V obtained by the AM process called Direct Metal Laser Sintering (DMLS). Moreover, the sub-surface microstructure alterations due to the process are also showed and commented.

  4. Characterization of Ti-6Al-4V open cellular foams fabricated by additive manufacturing using electron beam melting

    International Nuclear Information System (INIS)

    Murr, L.E.; Gaytan, S.M.; Medina, F.; Martinez, E.; Martinez, J.L.; Hernandez, D.H.; Machado, B.I.; Ramirez, D.A.; Wicker, R.B.

    2010-01-01

    Ti-6Al-4V open cellular foams were fabricated by additive manufacturing using electron beam melting (EBM). Foam models were developed from CT-scans of aluminum open cellular foams and embedded in CAD for EBM. These foams were fabricated with solid cell structures as well as hollow cell structures and exhibit tailorable stiffness and strength. The strength in proportion to the measured microindentation hardness is as much as 40% higher for hollow cell (wall) structures in contrast to solid, fully dense EBM fabricated components. Plots of relative stiffness versus relative density were in good agreement with the Gibson-Ashby model for open cellular foam materials. Stiffness or Young's modulus values measured using a resonant frequency-damping analysis technique were found to vary inversely with porosity especially for solid cell wall, open cellular structure foams. These foams exhibit the potential for novel biomedical, aeronautics, and automotive applications.

  5. The Effects of Dy Addition on Microstructure and Mechanical Properties of the As-Cast Mg-5Al-3Ca-2Nd Alloys.

    Science.gov (United States)

    Son, Hyeon-Taek; Kim, Yong-Ho; Yoo, Hyo-Sang

    2018-03-01

    The microstructure of the as-cast Mg-5Al-3Ca-2Nd-xDy alloys consists of α-Mg matrix, (Mg, Al)2Ca eutectic phase, Al-Nd and Al-Dy intermetallic compounds. α-Mg matrix morphology was changed from dendritic to equiaxed with the increase Dy addition. And grain size was remarkably refined. As Dy content was increased, yield strength was improved due to the refined grains and the homogeneous distribution of Al-Dy phase.

  6. Aluminum anode for aluminum-air battery - Part II: Influence of In addition on the electrochemical characteristics of Al-Zn alloy in alkaline solution

    Science.gov (United States)

    Park, In-Jun; Choi, Seok-Ryul; Kim, Jung-Gu

    2017-07-01

    Effects of Zn and In additions on the aluminum anode for Al-air battery in alkaline solution are examined by the self-corrosion rate, cell voltage, current-voltage characteristics, anodic polarization, discharge performance and AC impedance measurements. The passivation behavior of Zn-added anode during anodic polarization decreases the discharge performance of Al-air battery. The addition of In to Al-Zn anode reduces the formation of Zn passivation film by repeated adsorption and desorption behavior of In ion onto anode surface. The attenuated Zn passive layer by In ion attack leads to the improvement of discharge performance of Al-air battery.

  7. Facile fabrication of carbon microspheres decorated with B(OH) 3 and α-Fe 2 O 3 nanoparticles: superior microwave absorption

    KAUST Repository

    Zhong, Bo

    2017-06-02

    We demonstrate that novel three-dimensional (3D) B(OH)3 and α-Fe2O3 nanoparticles decorated carbon microspheres (B(OH)3/α-Fe2O3-CMSs) can be fabricated via a facile thermal treatment process. The carbon microspheres with diameter of 1 to 3 μm and decorated B(OH)3 and α-Fe2O3 nanoparticles with diameters of several to tens of nanometers are successfully fabricated. These novel 3D B(OH)3/α-Fe2O3-CMS composites exhibit enhanced microwave absorption with tunable strong absorption wavebands in the frequency range of 2–18 GHz. They have a minimum reflection loss (RL) value of -52.69 dB at a thickness of 3.0 mm, and the effective absorption bandwidth for RL less than -10 dB is as large as 5.64 GHz. The enhanced microwave absorption performance arises from the synergy of the impedance matching caused by the B(OH)3 nanoparticles, dielectric loss as well as the enhancement of multiple reflection among 3D α-Fe2O3 nanocrystals. These results provide a new strategy to tune electromagnetic properties and enhance the capacity of high-efficient microwave absorbers.

  8. Facile fabrication of carbon microspheres decorated with B(OH) 3 and α-Fe 2 O 3 nanoparticles: superior microwave absorption

    KAUST Repository

    Zhong, Bo; Wang, Chaojun; Yu, Yuanlie; Xia, Long; Wen, Guangwu

    2017-01-01

    We demonstrate that novel three-dimensional (3D) B(OH)3 and α-Fe2O3 nanoparticles decorated carbon microspheres (B(OH)3/α-Fe2O3-CMSs) can be fabricated via a facile thermal treatment process. The carbon microspheres with diameter of 1 to 3 μm and decorated B(OH)3 and α-Fe2O3 nanoparticles with diameters of several to tens of nanometers are successfully fabricated. These novel 3D B(OH)3/α-Fe2O3-CMS composites exhibit enhanced microwave absorption with tunable strong absorption wavebands in the frequency range of 2–18 GHz. They have a minimum reflection loss (RL) value of -52.69 dB at a thickness of 3.0 mm, and the effective absorption bandwidth for RL less than -10 dB is as large as 5.64 GHz. The enhanced microwave absorption performance arises from the synergy of the impedance matching caused by the B(OH)3 nanoparticles, dielectric loss as well as the enhancement of multiple reflection among 3D α-Fe2O3 nanocrystals. These results provide a new strategy to tune electromagnetic properties and enhance the capacity of high-efficient microwave absorbers.

  9. Influence of 8-hydroxyquinoline addition on the corrosion behavior of commercial Al and Al-HO411 alloys in NaOH aqueous media

    International Nuclear Information System (INIS)

    Soliman, H.N.

    2011-01-01

    Highlights: → The corrosion of commercial Al alloy is higher than that of Al-HO411 alloy. → The inhibition efficiency increases with the increasing of 8-hydroxyquinoline (8HQ) concentration. → The inhibition efficiencies of Al-HO411 samples are higher than those of commercial Al. → The 8HQ is promising candidate to be added to the coating systems as active anti-corrosive component for corrosion protection of both alloys. - Abstract: The effect of 8-hydroxyquinoline (8HQ) on the corrosion inhibition of commercial Al and Al-HO411 alloys has been investigated in NaOH solutions. Results showed that the inhibition efficiency was increased with increasing concentration of 8HQ. Al-HO411 alloy exhibited higher corrosion resistance and inhibition efficiency than the commercial Al. Examination of both samples was studied by means of optical microscope as well as energy-dispersive X-ray spectrometer. The crystallographic structure of both samples was analyzed by means of X-ray diffractometry. It was observed that protective films are formed on the surfaces that play an essential role in the corrosion inhibition of the alloys under investigation.

  10. Effect of trace addition of al on microstructure, texture and tensile ductility of Mg-6Zn-0.5Er alloy

    Directory of Open Access Journals (Sweden)

    Xiaobing Zheng

    2016-06-01

    Full Text Available The effects of trace addition of Al on the microstructure and mechanical properties of the as-extruded Mg-6Zn-0.5Er alloy were investigated in the present investigation. The results showed that the trace addition of Al affected the mechanical properties significantly. The elongation of the extruded alloy was improved markedly from 17 to 25% with the trace addition of Al. It is suggested that the improvement of ductility was mainly attributed to the modification of basal texture of the as-extruded alloy, resulting from the complete dynamic recrystallization due to the trace addition of Al. In addition, the existence of the complete dynamic recrystallization led to an obvious increase in the number fraction of high angle grain boundaries, the average misorientation angle and Schmid factors for the (0001 〈112¯0〉 slip, which also have contributed to the improvement of ductility.

  11. Influence of the addition of chromium in the microstructure and property of Cu-Al-Ni shape memory alloy

    International Nuclear Information System (INIS)

    Teixeira, C.A.; Coelho, R.E.; Lima, P.C. de; Carvalho, C.O. de; Conrado, L.C.

    2016-01-01

    The Copper based alloys with addition of a fourth element have been studied for 20 years. These alloys, depending on their composition present shape memory effect structure and now a day possess a diversity of applications. Considering the importance of these materials, it was developed in this research alloys of Cu-Al-Ni with addition of Cr in different percentages (0.2, 0.4, 0.7 and 2.26wt.%). A plasma furnace (Company-EDG, model-Discovery), with vacuum control and argon gas injection, was utilized. Posteriorly, the samples underwent heat treatment of solubilization. This treatment consisted in submitting all samples to a temperature of 900 deg C for 1 hour and followed by water solution (salt, water, ice and alcohol) quenching at a temperature of -10 deg C. The samples were polished and etched with Ferric Chloride. All samples were analyzed X-ray Fluorescence, Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). XRD was carried out with a tension 30kV from 25 deg to 100 deg. It was possible to verify, through the obtained SEM images, that Cr has a fundamental role in the martensite structure evolution and with XRD analyses it was observed that with the increase of Cr, results in the formation of phases 18R and 2H with a decrease of phase γ2, the last one unwanted to this type of alloy. (author)

  12. Aminobenzoate modified MgAl hydrotalcites as a novel smart additive of reinforced concrete for anticorrosion applications

    NARCIS (Netherlands)

    Yang, Z.; Fischer, H.R.; Cerezo, J.; Mol, J.M.C.; Polder, R.B.

    2013-01-01

    A carbonate form of MgAl hydrotalcite, Mg(2)Al-CO3 and its p-aminobenzoate (pAB) modified derivative, Mg(2)Al-pAB, were synthesized and characterized by means of XRD, FT-IR and TG/DSC. The anticorrosion behavior of Mg(2)Al-pAB was evaluated based on open circuit potential (OCP) of carbon steel in

  13. Band structure and optical properties of highly anisotropic LiBa2[B10O16(OH)3] decaborate crystal

    International Nuclear Information System (INIS)

    Smok, P.; Kityk, I.V.; Berdowski, J.

    2003-01-01

    The band structure (BS), charge density distribution and linear-optical properties of the anisotropic crystal LiBa 2 [B 10 O 16 (OH) 3 ] (LBBOH) are calculated using a self-consistent norm-conserving pseudopotential method within the framework of the local-density approximation theory. A high anisotropy of the band energy gap (4.22 eV for the E parallel b, 4.46 eV for the E parallel c) and giant birefringence (up to 0.20) are found. Comparison of the theoretically calculated and the experimentally measured polarised spectra of the imaginary part of the dielectric susceptibility ε 2 shows a good agreement. The anisotropy of the charge density distribution, BS dispersion and of the optical spectra originate from anisotropy between the 2p z B-2p z O and 2p y,x B-2p y,y O bonding orbitals. The observed anisotropy in the LBBOH is principally different from that of β-BaB 2 O 4 (BBO) single crystals. In the LBBOH single crystals the anisotropy of optical and charge density distribution is caused by different projection of the orbitals originating from particular borate clusters on the particular crystallographic axes, contrary to the BBO, where the anisotropy is caused prevailingly by a different local site symmetry of oxygen within the borate planes. The observed anisotropy is analysed in terms of the band energy dispersion and space charge density distribution

  14. The effect of Cu addition and milling contaminations on the microstructure evolution of ball milled Al-Pb alloy during sintering

    International Nuclear Information System (INIS)

    Zhu, M.; Ouyang, L.Z.; Wu, Z.F.; Zeng, M.Q.; Li, Y.Y.; Zou, J.

    2006-01-01

    Al-10 wt.%Pb and Al-10 wt.%Pb-x wt.%Cu (x = 0-7.0) bulk alloys were prepared by sintering the mechanically alloyed powders at various temperatures. The microstructure changes of the as consolidated powders in the course of sintering were analyzed by differential scanning calorimetry, scanning electron microscopy, X-ray diffraction analysis and transmission electron microscopy. It has been found that, with respect to the Al-10 wt.%Pb-x wt.%Cu alloy, CuAl 2 and Cu 9 Al 4 phases formed in the milling process, and the amount of CuAl 2 phase increased while the Cu 9 Al 4 phase disappeared gradually in the sintering process. In both Al-10 wt.%Pb and Al-10 wt.%Pb-x wt.%Cu alloys, the sintering process results in the coarsening of Pb phase and the growth rate of Pb phase fulfills the Lifshitz-Slyozov-Wagner equation even though the size of the Pb phase was in nanometer range. The Pb particle exhibits cuboctahedral morphology and has a cubic to cubic orientation relationship with the Al matrix. The addition of Cu strongly depressed the growth rate of Pb. Contamination induced by milling has apparent influence on the microstructure of the sintered alloys. Al 7 Cu 2 Fe and aluminium oxide phases were identified in the sintered alloys. The cuboctahedral morphology of Pb particles was broken up by the presence of the oxide phase

  15. Influence of silver addition on the microstructure and mechanical properties of squeeze cast Mg-6Al-1Sn-0.3Mn-0.3Ti

    International Nuclear Information System (INIS)

    Acikgoez, Sehzat; Sevik, Hueseyin; Kurnaz, S.Can

    2011-01-01

    Graphical abstract: Highlights: → X-ray diffractometry reveals that the main phases are α-Mg, α-Ti, β-Mg 17 Al 12 and Al 8 Mn 5 in the base alloy. → With addition of silver, Al 81 Mn 19 phase was found. → The mechanical properties of the base alloy are improved with addition of silver. → The fracture surface of base alloy shows relatively deeper and more amount of dimples than that of alloys containing silver. - Abstract: In this study, the effect of silver (0, 0.2, 0.5, and 1 wt.%) on the microstructure and mechanical properties of a magnesium-based alloy (Mg-Al 6 wt.%-Sn 1 wt.%-Mn 0.3 wt.%-Ti 0.3 wt.%) were investigated. The alloys were produced under a controlled atmosphere by a squeeze-casting process. X-ray diffractometry revealed that the main phases are α-Mg, α-Ti, β-Mg 17 Al 12 and Al 8 Mn 5 in the all of alloys. In addition to, Al 81 Mn 19 phase was found with Ag additive. Besides, the amount of β-Mg 17 Al 12 phase was decreased with increasing the amount of Ag. The strength of the base alloy was increased by solid solution mechanism and decreasing the amount of β-Mg 17 Al 12 phase with addition of Ag. Furthermore, existence of Al 81 Mn 19 phase can be acted an important role in the increase on the mechanical properties of the alloys.

  16. Effect of Cr and Mn addition and heat treatment on AlSi3Mg casting alloy

    Energy Technology Data Exchange (ETDEWEB)

    Tocci, Marialaura, E-mail: m.tocci@unibs.it [Department of Mechanical and Industrial Engineering, University of Brescia, Via Branze 38, 25123 Brescia (Italy); Donnini, Riccardo, E-mail: riccardo.donnini@cnr.it [National Research Council of Italy (CNR), Institute of Condensed Matter Chemistry and Technologies for Energy (ICMATE), Via R. Cozzi 53, 20125 Milan (Italy); Angella, Giuliano, E-mail: giuliano.angella@cnr.it [National Research Council of Italy (CNR), Institute of Condensed Matter Chemistry and Technologies for Energy (ICMATE), Via R. Cozzi 53, 20125 Milan (Italy); Pola, Annalisa, E-mail: annalisa.pola@unibs.it [Department of Mechanical and Industrial Engineering, University of Brescia, Via Branze 38, 25123 Brescia (Italy)

    2017-01-15

    In the present paper the effect of heat treatment on an AlSi3Mg alloy with and without Cr and Mn addition was investigated. Beside the well-known modification of the morphology of Fe-containing intermetallics, it was found that Cr and Mn allowed the formation of dispersoids in the aluminium matrix after solution heat treatment at 545 °C, as shown by scanning transmission electron microscope observations. These particles were responsible of the enhanced Vickers microhardness of the aluminium matrix in comparison with the base alloy after solution treatment and quenching, according to dispersion hardening mechanism. The presence of these particles was not affected by ageing treatment, which instead allowed the precipitation of β-Mg{sub 2}Si, as shown by the elaboration of differential scanning calorimeter curves. The formation of dispersoids and the study of their effect on mechanical properties can represent an interesting development for applications at high temperatures of casting alloys due to their thermal stability compared to other strengthening phases as β-Mg{sub 2}Si. - Highlights: •Cr and Mn successfully modified the morphology of Fe-containing intermetallics. •Cr- and Mn-dispersoids formed in the aluminium matrix during solution treatment. •Dispersion hardening was detected after solution treatment for Cr-containing alloy. •The dispersion hardening effect was maintained after ageing treatment.

  17. Microstructure-mechanical property relationships for Al-Cu-Li-Zr alloys with minor additions of cadmium, indium or tin

    Science.gov (United States)

    Blackburn, L. B.; Starke, E. A., Jr.

    1989-01-01

    Minor amounts of cadmium, indium or tin were added to a baseline alloy with the nominal composition of Al-2.4Cu-2.4Li-0.15Zr. These elements were added in an attempt to increase the age-hardening response of the material such that high strengths could be achieved through heat-treatment alone, without the need for intermediate mechanical working. The alloy variant containing indium achieved a higher peak hardness in comparison to the other alloy variations, including the baseline material, when aged at temperatures ranging from 160 C to 190 C. Tensile tests on specimens peak-aged at 160 indicated the yield strength of the indium-bearing alloy increased by approximately 15 percent compared to that of the peak-aged baseline alloy. In addition, the yield strength obtained in the indium-bearing alloy was comparable to that reported for similar baseline material subjected to a 6 percent stretch prior to peak-aging at 190 C. The higher strength levels obtaied for the indium-bearing alloy are attributed to increased number densities and homogeneity of both the T1 and theta-prime phases, as determined by TEM studies.

  18. Influence of Al{sub 2}O{sub 3} addition on microstructure and mechanical properties of 3YSZ-Al{sub 2}O{sub 3} composites

    Energy Technology Data Exchange (ETDEWEB)

    Abden, Md. Jaynul [International Islamic Univ., Chittagong (Bangladesh). Dept. of Electrical and Electronic Engineering; Afroze, Jannatul Dil [Noakhali Science and Technology Univ. (Bangladesh). Faculty of Science and Engineering; Gafur, Md. Abdul [Bangladesh Council of Scientific and Industrial Research, Dhaka (Bangladesh). Pilot Plant and Process Development Centre; Chowdhury, Faruque-Uz-Zaman [Chittagong University of Engineering and Technology (Bangladesh). Dept. of Physics

    2015-07-01

    The effect of the amount of Al{sub 2}O{sub 3} content on microstructure, tetragonal phase stability and mechanical properties of 3YSZ-Al{sub 2}O{sub 3} composites are investigated in this study. The ceramic composites are obtained by means of uniaxial compacting at 210 MPa and green compacts are sintered at 1550 C for 3 h in air. The monoclinic zirconia (m-ZrO{sub 2}) phase has completely been transformed into tetragonal zirconia (t-ZrO{sub 2}) phase with corresponding higher Al{sub 2}O{sub 3} content. The t-ZrO{sub 2} grains induce transgranular fracture mode that has contribution in improvement of fracture toughness. The maximum flexural strength of 340 MPa, Vickers hardness value of 14.31 GPa and fracture toughness of 5.1 MPa x m{sup 1/2} in the composition containing 40 wt.-% Al{sub 2}O{sub 3} is attributed to the microstructure with t-ZrO{sub 2} grains as inter- and intragranular particles in the Al{sub 2}O{sub 3} grains, which makes it suitable for dental applications.

  19. Melting and solidification behavior of Cu/Al and Ti/Al bimetallic core/shell nanoparticles during additive manufacturing by molecular dynamics simulation

    Science.gov (United States)

    Rahmani, Farzin; Jeon, Jungmin; Jiang, Shan; Nouranian, Sasan

    2018-05-01

    Molecular dynamics (MD) simulations were performed to investigate the role of core volume fraction and number of fusing nanoparticles (NPs) on the melting and solidification of Cu/Al and Ti/Al bimetallic core/shell NPs during a superfast heating and slow cooling process, roughly mimicking the conditions of selective laser melting (SLM). One recent trend in the SLM process is the rapid prototyping of nanoscopically heterogeneous alloys, wherein the precious core metal maintains its particulate nature in the final manufactured part. With this potential application in focus, the current work reveals the fundamental role of the interface in the two-stage melting of the core/shell alloy NPs. For a two-NP system, the melting zone gets broader as the core volume fraction increases. This effect is more pronounced for the Ti/Al system than the Cu/Al system because of a larger difference between the melting temperatures of the shell and core metals in the former than the latter. In a larger six-NP system (more nanoscopically heterogeneous), the melting and solidification temperatures of the shell Al roughly coincide, irrespective of the heating or cooling rate, implying that in the SLM process, the part manufacturing time can be reduced due to solidification taking place at higher temperatures. The nanostructure evolution during the cooling of six-NP systems is further investigated. [Figure not available: see fulltext.

  20. Effect of the Heusler phase formation on the magnetic behavior of the Cu–10 wt.%Mn alloy with Al and Ag additions

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, T.M., E-mail: thaisa.mary@gmail.com [Instituto de Química – UNESP, Caixa Postal 355, 14801-970 Araraquara, SP (Brazil); Adorno, A.T.; Santos, C.M.A. [Instituto de Química – UNESP, Caixa Postal 355, 14801-970 Araraquara, SP (Brazil); Silva, R.A.G. [Departamento de Ciências Exatas e da Terra – UNIFESP, 09972-270 Diadema, SP (Brazil); Magnani, M. [Instituto de Química – UNESP, Caixa Postal 355, 14801-970 Araraquara, SP (Brazil)

    2015-09-15

    Highlights: • The presence of the Cu{sub 2}MnAl phase was observed in annealed alloys. • Al and Ag additions shift the equilibrium concentration to higher Al values. • There is a correlation between the Ag-rich phase and the Cu{sub 2}MnAl phase. - Abstract: In this work, the formation of the Cu{sub 2}AlMn Heusler phase and its influence on the magnetic behavior of the Cu–Mn–Al–Ag alloys in the range of 8–10 wt.% of aluminum and 2–4 wt.% of silver were studied using differential scanning calorimetry (DSC), transmission electron microscopy (TEM), high-resolution TEM (HRTEM) and saturation magnetization measurements at 4 K. The results showed that there is a correlation between the presence of the Ag-rich phase and the formation of the Cu{sub 2}MnAl phase.

  1. The effect of vanadium and grain refiner additions on the nucleation of secondary phases in 1XXX Al alloys

    Energy Technology Data Exchange (ETDEWEB)

    Allen, C.M.; O' Reilly, K.A.Q.; Evans, P.V.; Cantor, B.

    1999-11-26

    High purity Al-0.3 wt% Fe-0.1 wt% Si alloys with different Si, V and grain refiner contents were melt spun to produce microstructures of submicron secondary phases entrained in a higher melting point Al matrix. On reheating, a dispersion of eutectic liquid droplets forms that represents an exaggerated version of the liquid puddles that solidify punched-off between Al dendrite arms during conventional casting. The subsequent resolidification of the droplets, analyzed using differential scanning calorimetry (DSC), allows the nucleation-controlled aspects of secondary phase selection to be studied. The droplets solidify as the metastable FeAl{sub m} phase in ribbons containing {approx{underscore}equal}500 ppm V or {approx{underscore}equal}100 ppm V plus Al-Ti-B, Al-Ti-C or Al-B grain refiner. This phase contributes to the fir-tree surface defect in commercial sheet products. this work suggests that the combination of V and Al-Ti-B promotes FeAl{sub m} in commercial ingots, and confirms that solidification rate and bulk Si content also influence phase content.

  2. A density functional theory study of arsenic immobilization by the Al(III)-modified zeolite clinoptilolite

    NARCIS (Netherlands)

    Awuah, Joel B.; Dzade, N.Y.; Tia, Richard; Adei, Evans; Kwakye-Awuah, Bright; Catlow, C. Richard A.; de Leeuw, Nora H.

    2016-01-01

    We present density functional theory calculations of the adsorption of arsenic acid (AsO(OH)3) and arsenous acid (As(OH)3) on the Al(III)-modified natural zeolite clinoptilolite under anhydrous and hydrated conditions. From our calculated adsorption energies, we show that adsorption of both arsenic

  3. Effect of Cr, Ti, V, and Zr Micro-additions on Microstructure and Mechanical Properties of the Al-Si-Cu-Mg Cast Alloy

    Science.gov (United States)

    Shaha, S. K.; Czerwinski, F.; Kasprzak, W.; Friedman, J.; Chen, D. L.

    2016-05-01

    Uniaxial static and cyclic tests were used to assess the role of Cr, Ti, V, and Zr additions on properties of the Al-7Si-1Cu-0.5Mg (wt pct) alloy in as-cast and T6 heat-treated conditions. The microstructure of the as-cast alloy consisted of α-Al, eutectic Si, and Cu-, Mg-, and Fe-rich phases Al2.1Cu, Al8.5Si2.4Cu, Al5.2CuMg4Si5.1, and Al14Si7.1FeMg3.3. In addition, the micro-sized Cr/Zr/Ti/V-rich phases Al10.7SiTi3.6, Al6.7Si1.2TiZr1.8, Al21.4Si3.4Ti4.7VZr1.8, Al18.5Si7.3Cr2.6V, Al7.9Si8.5Cr6.8V4.1Ti, Al6.3Si23.2FeCr9.2V1.6Ti1.3, Al92.2Si16.7Fe7.6Cr8.3V1.8, and Al8.2Si30.1Fe1.6Cr18.8V3.3Ti2.9Zr were present. During solution treatment, Cu-rich phases were completely dissolved, while the eutectic silicon, Fe-, and Cr/Zr/Ti/V-rich intermetallics experienced only partial dissolution. Micro-additions of Cr, Zr, Ti, and V positively affected the alloy strength. The modified alloy in the T6 temper during uniaxial tensile tests exhibited yield strength of 289 MPa and ultimate tensile strength of 342 MPa, being significantly higher than that for the Al-Si-Cu-Mg base. Besides, the cyclic yield stress of the modified alloy in the T6 state increased by 23 pct over that of the base alloy. The fatigue life of the modified alloy was substantially longer than that of the base alloy tested using the same parameters. The role of Cr, Ti, V, and Zr containing phases in controlling the alloy fracture during static and cyclic loading is discussed.

  4. Cr(OH)3-NPs-CNC hybrid nanocomposite: a sorbent for adsorptive removal of methylene blue and malachite green from solutions.

    Science.gov (United States)

    Nekouei, Farzin; Nekouei, Shahram; Keshtpour, Farzaneh; Noorizadeh, Hossein; Wang, Shaobin

    2017-11-01

    In this article, Cr(OH) 3 nanoparticle-modified cellulose nanocrystal (CNC) as a novel hybrid nanocomposite (Cr(OH) 3 -NPs-CNC) was prepared by a simple procedure and used as a sorbent for adsorptive removal of methylene blue (MB) and malachite green (MG) from aqueous solution. Different kinetic models were tested, and the pseudo-second-order kinetic model was found more suitable for the MB and MG adsorption processes. The BET and Langmuir models were more suitable for the adsorption processes of MB and MG. Thermodynamic studies suggested that the adsorption of MB and MG onto Cr(OH) 3 -NPs-CNC nanocomposite was a spontaneous and endothermic process. The maximum adsorption capacities for MB and MG were reached 106 and 104 mg/g, respectively, which were almost two times higher than unmodified CNC. The chemical stability and leaching tests of the Cr(OH) 3 -NPs-CNC hybrid nanocomposite showed that only small amounts of chromium were leached into the solution.

  5. Effects of additives on the sintering of UO2.Gd2O3 nuclear fuel

    International Nuclear Information System (INIS)

    Pagano Junior, Luciano

    2009-01-01

    The addition of 0.5wt% TiO 2 , Nb 2 O 5 , SiO 2 , Fe 2 O 3 and Al(OH) 3 in the UO 2 ·7%Gd 2 O 3 nuclear fuel and the effect on its sintering kinetics under a 99.999% H 2 atmosphere were investigated by stepwise isothermal dilatometry. This fuel, used as burnable poison in nuclear power plants, presents a diffusion barrier around 1573 K that impairs densification. The aid of the sintering additives TiO 2 , Al(OH) 3 , Nb 2 O 5 and Fe 2 O 3 turned out to be effective to obtain the required final density, unlike the effect observed for the SiO 2 -doped composition. The activation energy for the intermediate sintering stage was calculated by stepwise isothermal dilatometry method and a positive correlation with the sintered body density was found. The method was valid for part of the intermediate sintering stage, in the range from 1200 K to 1700 K for the doped compositions and with no additive, except for the SiO 2 -doped one, whose validity range was between 1500 K and 1900 K. The energy-density correlation was not valid for the SiO 2 -doped composition, whose effect was to reduce the final density. This anomalous behavior may be attributed to the intense loss of Si mass, probably due to lower oxides volatilization, during the initial sintering stage at temperatures lower than 1173 K. Similar loss, but no so intense, was observed for the Al(OH) 3 -doped composition in the temperature interval from 1173 K to 1573 K. The Si concentration decrease to residual values of dozens of parts per million may explain its anomalous behavior. The positive correlation between activation energy and sintered body density may be explained by the inhibitor role played by the TiO 2 , Nb 2 O 5 , Fe 2 O 3 and Al(OH) 3 additives on the diffusion mechanisms that enhance the coarsening regime. As a consequence, the densification mechanisms are favored in the competition for the surface free energy. The coarsening-densification transition temperature model, originally suggested for the UO 2

  6. Thermal conductivity enhancement and sedimentation reduction of magnetorheological fluids with nano-sized Cu and Al additives

    Science.gov (United States)

    Rahim, M. S. A.; Ismail, I.; Choi, S. B.; Azmi, W. H.; Aqida, S. N.

    2017-11-01

    This work presents enhanced material characteristics of smart magnetorheological (MR) fluids by utilizing nano-sized metal particles. Especially, enhancement of thermal conductivity and reduction of sedimentation rate of MR fluids those are crucial properties for applications of MR fluids are focussed. In order to achieve this goal, a series of MR fluid samples are prepared using carbonyl iron particles (CIP) and hydraulic oil, and adding nano-sized particles of copper (Cu), aluminium (Al), and fumed silica (SiO2). Subsequently, the thermal conductivity is measured by the thermal property analyser and the sedimentation of MR fluids is measured using glass tubes without any excitation for a long time. The measured thermal conductivity is then compared with theoretical models such as Maxwell model at various CIP concentrations. In addition, in order to show the effectiveness of MR fluids synthesized in this work, the thermal conductivity of MRF-132DG which is commercially available is measured and compared with those of the prepared samples. It is observed that the thermal conductivity of the samples is much better than MRF-132DG showing the 148% increment with 40 vol% of the magnetic particles. It is also observed that the sedimentation rate of the prepared MR fluid samples is less than that of MRF-132DG showing 9% reduction with 40 vol% of the magnetic particles. The mixture optimized sample with high conductivity and low sedimentation was also obtained. The magnetization of the sample recorded an enhancement of 70.5% when compared to MRF-132DG. Furthermore, the shear yield stress of the sample were also increased with and without the influence of magnetic field.

  7. Glass forming ability and mechanical properties of the NiZrTiSi amorphous alloys modified with Al, Cu and Nb additions

    International Nuclear Information System (INIS)

    Czeppe, Tomasz; Ochin, Patrick; Sypien, Anna

    2007-01-01

    The composition of the amorphous alloy Ni 59 Zr 20 Ti 16 Si 5 was modified with 2-9 at.% additions of Cu, Al and Nb. The ribbons and the bars 2.7 mm in diameter were prepared by melt spinning and injection casting from the alloys of the compositions: Ni 56 Zr 18 Ti 16 Si 5 Al 3 Cu 2 , Ni 56 Zr 18 Ti 13 Al 6 Si 5 Cu 2 , Ni 56 Zr 16 Ti 12 Nb 9 Al 3 Cu 2 Si 2 and Ni 56 Zr 16 Ti 12 Nb 6 Al 6 Cu 2 Si 2 . All ribbons were amorphous up to the resolution of the X-ray diffraction and conventional transmission electron microscopy, however rods were partially crystalline. Increase of Al content lowered and Nb content slightly increased crystallization start temperature T x and glass transition temperature T g . The influence of composition changes on the overcooled liquid range ΔT was more complicated. The increase of Nb and decrease of Ti and Zr content led to the remarkable increase of the liquidus temperature T l . As a result GFA calculated as T g /T l was lowered to the values about 0.63 for 6 and 9 at.% Nb addition. The activation energies for primary crystallization in alloy with 6 at.% Al and 6 at.% of Nb, were determined. The changes of tensile test strength and microhardness with Al and Nb additions showed hardening effect caused by Nb additions and increase in fracture strength with increasing Al content

  8. Si3N4 ceramic cutting tool sintered with CeO2 and Al2O3 additives with AlCrN coating

    Directory of Open Access Journals (Sweden)

    José Vitor Candido Souza

    2011-12-01

    Full Text Available Ceramic cutting tools are showing a growing market perspective in terms of application on machining operations due to their high hardness, wear resistance, and machining without a cutting fluid, therefore are good candidates for cast iron and Nickel superalloys machining. The objective of the present paper was the development of Si3N4 based ceramic cutting insert, characterization of its physical and mechanical properties, and subsequent coating with AlCrN using a PVD method. The characterization of the coating was made using an optical profiler, XRD, AFM and microhardness tester. The results showed that the tool presented a fracture toughness of 6.43 MPa.m½ and hardness of 16 GPa. The hardness reached 31 GPa after coating. The machining tests showed a decrease on workpiece roughness when machining with coated insert, in comparison with the uncoated cutting tool. Probably this fact is related to hardness, roughness and topography of AlCrN.

  9. The effect of CuAl addition on the magnetic property, thermal stability and corrosion resistance of the sintered NdFeB magnets

    Science.gov (United States)

    Liu, Y. L.; Liang, J.; He, Y. Ch.; Li, Y. F.; Wang, G. F.; Ma, Q.; Liu, F.; Zhang, Y.; Zhang, X. F.

    2018-05-01

    To improve the coercivity of the Nd-Fe-B sintered magnets, the Cu29.8Al70.2 (at.%) powders with low melting point were introduced into the Nd-Fe-B magnets. The magnetic properties, microstructure, thermal stability and corrosion behavior of the sintered magnets with different amount of Cu29.8Al70.2 (0,0.25,0.50,0.75,1.0 wt.%) were investigated. When the amount of doped Cu29.8Al70.2 was less than 0.75 wt.%, the coercivity was improved, especially that of the magnets with 0.25 wt.% Cu29.8Al70.2, markedly increased to 13.97 kOe from 12.67 kOe (without CuAl). The improvement of magnetic properties could be attributed to enhanced wettability between Nd2Fe14B phase and Nd-rich phase and decreased exchange coupling between grains, which depended on the optimization of grain boundary microstructure and their distribution by codoping Cu and Al. With the addition of 0-1.0 wt.% Cu29.8Al70.2 powders, the reversible temperature coefficients of remanence and coercivity of the magnets could be also improved. The corrosion resistances was also found to be improved through small addition of Cu29.8Al70.2 powder in 3.5 wt.% NaCl solution by electrochemical and immersion tests, which could be due to the enhancement of the Nd-rich intergranular phase by addition Cu29.8Al70.2.

  10. Effect of Ce addition on microstructure of Al20Cu2Mn3 twin phase in an Al–Cu–Mn casting alloy

    International Nuclear Information System (INIS)

    Chen Zhongwei; Chen Pei; Li Shishun

    2012-01-01

    Highlights: ► Rare earth element Ce can retard the formation of the Al 20 Cu 2 Mn 3 twin phase in an Al–Cu–Mn casting alloy. ► Patterns of the particles of the Al 20 Cu 2 Mn 3 phase in Al–Cu–Mn free Ce alloy are more diverse. ► The symmetry of neighboring components of twins is characterized by glide reflection and reflection. ► The twins of Al 20 Cu 2 Mn 3 phase can enhance the mechanical properties of the Al–Cu–Mn casting alloys. - Abstract: Effects of Ce addition on microstructure of Al 20 Cu 2 Mn 3 twin phase and mechanical properties of an Al–Cu–Mn casting alloy were investigated by transmission electron microscopy, selected area electron diffraction, high resolution transmission electron microscopy and tensile test. The results show that rare earth element Ce can retard the formation of the Al 20 Cu 2 Mn 3 phase in the Al–Cu–Mn alloy. Compared with the Ce containing alloy, patterns of particles of the Al 20 Cu 2 Mn 3 phase in the Al–Cu–Mn free Ce alloy are more diverse. The symmetry of neighboring components of twins is characterized by glide reflection and reflection. In addition, twins of the Al 20 Cu 2 Mn 3 phase can enhance the mechanical properties of the Al–Cu–Mn alloy.

  11. Stabilization effect of Zr and Ti additions on the ageing characteristics of Al-1 wt% Si alloy through a creep study

    Energy Technology Data Exchange (ETDEWEB)

    Deaf, G.H.; Beshai, M.H.N.; Abd El Khalek, A.M.; Graiss, G. [Ain Shams Univ., Cairo (Egypt). Dept. of Physics; Kenawy, M.A. [Ain Shams Univ., Cairo (Egypt). Womens Coll.

    1997-12-31

    Al-1 wt% Si and Al-1 wt% Si-0.1 wt% Zr-0.1 wt% Ti alloys were used to trace the effect of Zr and Ti additions on the behaviour of the steady state creep. After solid solution treatment specimens of both alloys were aged at 623, 673, 723 and 773 K and creep tests were performed at room temperature by applying stresses of 60.0, 62.4, 64.7 and 67.1 MPa. The results showed a sound stabilization effect of Zr and Ti on the ageing characteristics of binary Al-1 wt% Si alloy. Values of the applied stress sensitivity parameter, m, obtained were in the range of (20-34) for Al-Si alloy and (14-19) for Al-Si-Zr-Ti alloy. Time to rupture was found to be strongly increased by Zr and Ti additions. The activation energies of the precipitation process involved were found to be 81.9 kJ/mole and 33.7 kJ/mole of the Al-Si and Al-Si-Zr-Ti alloys respectively. (orig.) 17 refs.

  12. The Effect of Ag Addition on the Enhancement of the Thermal and Mechanical Properties of CuZrAl Bulk Metallic Glasses

    Directory of Open Access Journals (Sweden)

    Tsan-Man Chung

    2016-09-01

    Full Text Available In this study, the thermal and mechanical properties of Cu50−xZr43Al7Agx (x = 0, 3, 4, 5, 6 bulk metallic glasses (BMGs are investigated by using an X-ray diffractometer (XRD, a differential scanning calorimeter (DSC, differential thermal analysis (DTA, a Vickers hardness tester, a material test system (MTS, scanning electron microscopy (SEM, and transmission electron microscopy (TEM. Cu50−xZr43Al7Agx (x = 0, 3, 4, 5, 6 BMGs were made by arc-melting and an injection casting process. The results revealed that the glass transition temperature (Tg and the crystallization temperature (Tx of CuZrAl alloy decreased with the Ag addition. Hence, the supercooled liquid region and γ of Cu45Zr43Al7Ag5 alloy increased to 76 K and 0.42, respectively. The thermal stability and glass forming ability of CuZrAlAg BMG alloys were enhanced by the microalloyed Ag content. The room temperature compressive fracture strength and strain measured of Cu47Zr43Al7Ag3 were about 2200 MPa and 2.1%, respectively. The distribution of vein patterns and the formation of nanocrystalline phases on the fracture surface of Cu47Zr43Al7Ag3 alloy can be observed by SEM and TEM to be significant, indicating a typical ductile fracture behavior and an improved plasticity of alloys with the addition of microalloyed Ag from 0 to 6 atom %.

  13. Influence of Ti addition and sintering method on microstructure and mechanical behavior of a medium-entropy Al0.6CoNiFe alloy

    International Nuclear Information System (INIS)

    Fu, Zhiqiang; Chen, Weiping; Chen, Zhen; Wen, Haiming; Lavernia, Enrique J.

    2014-01-01

    The influence of Ti addition and sintering method on the microstructure and mechanical behavior of a medium-entropy alloy, Al 0.6 CoNiFe alloy, was studied in detail. Alloying behavior, microstructure, phase evolution and mechanical properties of Al 0.6 CoNiFe and Ti 0.4 Al 0.6 CoNiFe alloys were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), as well as by mechanical testing. During the mechanical alloying (MA) process, a supersaturated solid solution consisting of both BCC and FCC phases was formed in the Al 0.6 CoNiFe alloy. With Ti addition, the Ti 0.4 Al 0.6 CoNiFe alloy exhibited a supersaturated solid solution with a single FCC phase. Following hot pressing (HP), the HP sintered (HP’ed) Al 0.6 CoNiFe bulk alloy was composed of a major BCC phase and a minor FCC phase. The HP’ed Ti 0.4 Al 0.6 CoNiFe alloy exhibited a FCC phase, two BCC phases and a trace unidentified phase. Nanoscale twins were present in the HP’ed Ti 0.4 Al 0.6 CoNiFe alloy, where deformation twins were observed in the FCC phase. Our results suggest that the addition of Ti facilitated the formation of nanoscale twins. The compressive strength and Vickers hardness of HP’ed Ti 0.4 Al 0.6 CoNiFe alloy were slightly lower than the corresponding values of the HP’ed Al 0.6 CoNiFe alloy. In contrast with HP’ed Al 0.6 CoNiFe alloy, spark plasma sintered (SPS’ed) Al 0.6 CoNiFe alloy exhibited a major FCC phase and a minor BCC phase. Moreover, the SPS’ed Al 0.6 CoNiFe alloy exhibited a lower compressive strength and Vickers hardness, but singificantly higher plasticity, as compared to those of the HP’ed counterpart material

  14. Effect of Ta Additions on the Microstructure, Damping, and Shape Memory Behaviour of Prealloyed Cu-Al-Ni Shape Memory Alloys

    Directory of Open Access Journals (Sweden)

    Safaa N. Saud

    2017-01-01

    Full Text Available The influence of Ta additions on the microstructure and properties of Cu-Al-Ni shape memory alloys was investigated in this paper. The addition of Ta significantly affects the green and porosity densities; the minimum percentage of porosity was observed with the modified prealloyed Cu-Al-Ni-2.0 wt.% Ta. The phase transformation temperatures were shifted towards the highest values after Ta was added. Based on the damping capacity results, the alloy of Cu-Al-Ni-3.0 wt.% Ta has very high internal friction with the maximum equivalent internal friction value twice as high as that of the prealloyed Cu-Al-Ni SMA. Moreover, the prealloyed Cu-Al-Ni SMAs with the addition of 2.0 wt.% Ta exhibited the highest shape recovery ratio in the first cycle (i.e., 100% recovery, and when the number of cycles is increased, this ratio tends to decrease. On the other hand, the modified alloys with 1.0 and 3.0 wt.% Ta implied a linear increment in the shape recovery ratio with increasing number of cycles. Polarization tests in NaCl solution showed that the corrosion resistance of Cu-Al-Ni-Ta SMA improved with escalating Ta concentration as shown by lower corrosion current densities, higher corrosion potential, and formation of stable passive film.

  15. Effect of Ta Additions on the Microstructure, Damping, and Shape Memory Behaviour of Prealloyed Cu-Al-Ni Shape Memory Alloys.

    Science.gov (United States)

    Saud, Safaa N; Hamzah, E; Bakhsheshi-Rad, H R; Abubakar, T

    2017-01-01

    The influence of Ta additions on the microstructure and properties of Cu-Al-Ni shape memory alloys was investigated in this paper. The addition of Ta significantly affects the green and porosity densities; the minimum percentage of porosity was observed with the modified prealloyed Cu-Al-Ni-2.0 wt.% Ta. The phase transformation temperatures were shifted towards the highest values after Ta was added. Based on the damping capacity results, the alloy of Cu-Al-Ni-3.0 wt.% Ta has very high internal friction with the maximum equivalent internal friction value twice as high as that of the prealloyed Cu-Al-Ni SMA. Moreover, the prealloyed Cu-Al-Ni SMAs with the addition of 2.0 wt.% Ta exhibited the highest shape recovery ratio in the first cycle (i.e., 100% recovery), and when the number of cycles is increased, this ratio tends to decrease. On the other hand, the modified alloys with 1.0 and 3.0 wt.% Ta implied a linear increment in the shape recovery ratio with increasing number of cycles. Polarization tests in NaCl solution showed that the corrosion resistance of Cu-Al-Ni-Ta SMA improved with escalating Ta concentration as shown by lower corrosion current densities, higher corrosion potential, and formation of stable passive film.

  16. Improvement of the magnetic property, thermal stability and corrosion resistance of the sintered Nd-Fe-B magnets with Dy{sub 80}Al{sub 20} addition

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Beibei; Li, Xiangbin; Liang, Xiaolin [School of Physics and Technology, Wuhan University, Wuhan, Hubei (China); Yan, Gaolin, E-mail: gaolinyan@whu.edu.cn [School of Physics and Technology, Wuhan University, Wuhan, Hubei (China); Chen, Kan; Yan, Aru [Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang (China)

    2017-05-01

    To improve the coercivity and thermal stability of the Nd-Fe-B sintered magnets simultaneously, the Dy{sub 80}Al{sub 20} (at%) powders with low melting point were introduced into the Nd-Fe-B magnets. Additionally, the magnetic properties, microstructure and thermal stability of the sintered magnets with different amounts of Dy{sub 80}Al{sub 20} were investigated. By adding a small amount of Dy{sub 80}Al{sub 20}, the coercivity was significantly increased from 12.72 to 21.75 kOe. As indicated by the microstructure analysis, a well-developed core-shell structure was formed in the magnets with the addition of Dy{sub 80}Al{sub 20}. The improvement of magnetic properties could be attributed to the refined and uniform matrix phase, continuous grain boundaries and a (Nd, Dy){sub 2}Fe{sub 14}B hardening shell surrounding the matrix phase grains. With the addition of 0–4 wt% Dy{sub 80}Al{sub 20} powder, the reversible temperature coefficients of remanence (α) and coercivity (β) of the magnets could be improved from −0.117 to −0.108%/°C and −0.74 to −0.66%/°C in the range of 20–100 °C, respectively. Additionally, the irreversible loss of magnetic flux (hirr) decreased sharply as Dy{sub 80}Al{sub 20} powder was added. The results of temperature-dependent magnetic properties suggest that, the thermal stability of the magnets was effectively improved with the intergranular addition of Dy{sub 80}Al{sub 20} alloy. Also, the corrosion resistance was found to be improved through small addition of Dy{sub 80}Al{sub 20} powders This was partly due to the stability enhancement of the (Pr, Nd)-rich intergranular phase by Dy{sub 80}Al{sub 20}. - Highlights: • We successfully introduced the Dy{sub 80}Al{sub 20} alloy into the Nd-Fe-B magnets. • The magnetic properties and thermal stability of the Nd-Fe-B magnets were improved. • The corrosion resistance of the Nd-Fe-B magnets were improved.

  17. Effects of B4C Addition on the Laser Beam Welding Characteristics of Al/SiC MMCs Produced By P/M

    Directory of Open Access Journals (Sweden)

    Serdar KARAOĞLU

    2011-01-01

    Full Text Available Fusion weldability characteristics of metal matrix composites (MMC produced by powder metallurgy (P/M are usually insufficient due to unwanted micro-structural changes that occur during welding. This study aims to investigate the effects of B4C addition as reinforcement on the weld quality of Al/SiC MMCs. After the production of Al/SiC MMCs by P/M with or without the addition of B4C, laser beam welding (LBW characteristics of the materials were investigated by focusing on the integrity of the welds. Optical microscopy (OM, scanning electron microscopy (SEM, and energy dispersive X-ray analysis (EDX were utilized for the characterization of the welds. Results show that Al/SiC MMCs produced by P/M can not be easily welded by LBW, but weldability characteristics of the material can be improved by the addition of B4C.

  18. Effects of flux additives on the characteristics of Y2.95Al5O12:0.05Ce3+ phosphor: Particle growth mechanism and luminescence

    International Nuclear Information System (INIS)

    Chiang, Chung-Hao; Liu, Te-Hsing; Lin, Han-Yu; Kuo, Hung-Yi; Chu, Sheng-Yuan

    2013-01-01

    The dependence of the amount of the BaF 2 flux additive on the luminescence of Y 2.95 Al 5 O 12 :0.05Ce 3+ phosphors was investigated. The integrated emission intensity of Y 2.95 Al 5 O 12 :0.05Ce 3+ prepared without the flux was enhanced by 29% with the addition of BaF 2 flux at the optimum amount of 6 wt. %. Such an enhancement can be attributed to the purer phase of Y 3 Al 5 O 12 and the morphology change from the irregular shape to spherical shape with the smoother surface due to the flux. The morphology and luminescence of Y 2.95 Al 5 O 12 :0.05Ce 3+ prepared with the 6 wt. % BaF 2 flux additive (Sample II) were further compared with those of Y 2.95 Al 5 O 12 :0.05Ce 3+ prepared with the 7 wt. % H 3 BO 3 flux additive (Sample I). The particle size, particle shape, and integrated emission intensity (λ ex  = 450 nm) of the former were found to be larger, more regular, and 6% higher than those of the latter. The difference in the morphology of Samples I and II, which led to the difference in the emission intensity and the external quantum efficiency, were well explained by the particle growth mechanism

  19. Effect of phosphorus addition on the hydrotreating activity of NiMo/Al{sub 2}O{sub 3} carbide catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Sundaramurthy, V.; Dalai, A.K. [Catalysis and Chemical Reaction Engineering Laboratories, Department of Chemical Engineering, University of Saskatchewan, Saskatoon, SK S7N 5A9 (Canada); Adjaye, J. [Syncrude Edmonton Research Centre, Edmonton, AB T6N 1H4 (Canada)

    2007-07-30

    A series of phosphorus promoted {gamma}-Al{sub 2}O{sub 3} supported NiMo carbide catalysts with 0-4.5 wt.% P, 13 wt.% Mo and 2.5 wt.% Ni were synthesized and characterized by elemental analysis, pulsed CO chemisorption, BET surface area measurement, X-ray diffraction, near-edge X-ray absorption fine structure, DRIFT spectroscopy of CO adsorption and H{sub 2} temperature programmed reduction. X-ray diffraction patterns and CO uptake showed the P addition to NiMo/{gamma}-Al{sub 2}O{sub 3} carbide, increased the dispersion of {beta}-Mo{sub 2}C particles. DRIFT spectra of adsorbed CO revealed that P addition to NiMo/{gamma}-Al{sub 2}O{sub 3} carbide catalyst not only increases the dispersion of Ni-Mo carbide phase, but also changes the nature of surface active sites. The hydrodenitrogenation (HDN) and hydrodesulfurization (HDS) activities of these P promoted NiMo/{gamma}-Al{sub 2}O{sub 3} carbide catalysts were performed in trickle bed reactor using light gas oil (LGO) derived from Athabasca bitumen and model feed containing quinoline and dibenzothiophene at industrial conditions. The P added NiMo/{gamma}-Al{sub 2}O{sub 3} carbide catalysts showed enhanced HDN activity compared to the NiMo/{gamma}-Al{sub 2}O{sub 3} catalysts with both the feed stocks. The P had almost no influence on the HDS activity of NiMo/{gamma}-Al{sub 2}O{sub 3} carbide with LGO and dibenzothiophene. P addition to NiMo/{gamma}-Al{sub 2}O{sub 3} carbide accelerated C-N bond breaking and thus increased the HDN activity. (author)

  20. The dehydrogenation performance and reaction mechanisms of Li{sub 3}AlH{sub 6} with TiF{sub 3} additive

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Shu-Sheng [Materials and Thermochemistry Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); Graduate School of Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Yao; Sun, Li-Xian; Zhang, Jian; Zhao, Jun-Ning [Materials and Thermochemistry Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); Xu, Fen [Faculty of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian 116029 (China); Huang, Feng-Lei [State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081 (China)

    2010-05-15

    For Li{sub 3}AlH{sub 6} prepared by mechanical milling method, the dissociation reaction enthalpy and activation energy are calculated to be 22.1 kJ mol{sup -1} H{sub 2} and 133.7 {+-} 2.7 kJ mol{sup -1}, respectively. The dehydrogenation performance of Li{sub 3}AlH{sub 6} is greatly enhanced by TiF{sub 3} additive, especially in the kinetic behaviors. For the Li{sub 3}AlH{sub 6} + 10 mol% TiF{sub 3} sample, the starting temperature of dehydrogenation is obviously decreased by 60 C from that of pure Li{sub 3}AlH{sub 6} (190 C), and 3.0 wt.% H{sub 2} may be released within 1000 s at 120 C under an initial vacuum. With the amount of TiF{sub 3} increasing, the starting temperature decreases and the kinetics improves due to the decrease in the activation energy. The X-ray diffraction (XRD) together with thermogravimetric analysis (TGA) results show that there are three mechanochemical reactions involved during milling: i) Li{sub 3}AlH{sub 6} + TiF{sub 3} {yields} 3 LiF + Al + Ti + 3H{sub 2}, ii) Ti + H{sub 2} {yields} TiH{sub 2}, iii) 3 Al + Ti {yields} Al{sub 3}Ti. The in-situ formed Ti species (TiH{sub 2} and Al{sub 3}Ti) co-catalyze the thermal dehydrogenation of Li{sub 3}AlH{sub 6}. (author)

  1. Additional evaluation of alpha induced neutron production nuclear data. 9Be, 27Al, 28,29,30Si

    International Nuclear Information System (INIS)

    Murata, Toru; Shibata, Keiichi

    2005-01-01

    Alpha particle induced neutron production cross sections, emitted neutron energy spectrum and angular distributions were evaluated for the target nucleus 9 Be, 27 Al and Si isotopes; 28 Si, 29 Si and 30 Si in the incident energy region below 15 MeV. (author)

  2. Influence of additives on the microstructure and tensile properties of near-eutectic Al-10.8%Si cast alloy

    International Nuclear Information System (INIS)

    Mohamed, A.M.A.; Samuel, A.M.; Samuel, F.H.; Doty, H.W.

    2009-01-01

    The continuing quest for aluminum castings with enhanced mechanical properties for applications in the automotive industries has intensified the interest in aluminum-silicon alloys. In Al-Si alloys, the properties are influenced by the shape and distribution of the eutectic silicon particles in the matrix, as also by the iron intermetallics and copper phases that occur upon solidification. The detailed microstructure and tensile properties of as-cast and heat-treated new experimental alloy belonging to cast Al-Si near-eutectic alloys have been investigated as a function of Fe, Mn, Cu, and Mg content. Microstructural examination was carried out using optical microscopy, image analysis, and electron probe microanalysis (EPMA), wavelength dispersive spectroscopic (WDS) analysis facilities. Tensile properties upon artificial aging in the temperature range of 155-240 o C for 5 h were also investigated. The results show that the volume fraction of Fe-intermetallics increases as the iron or manganese contents increase. Compact polygonal or star-like particles form when the sludge factor is greater than 2.1. The Al 2 Cu phase was observed to dissolve almost completely during solution heat treatment of all the alloys studied, especially those containing high levels of Mg and Fe, while Al 5 Cu 2 Mg 8 Si 6 , sludge, and α-Fe phases were found to persist after solution heat treatment. The β-Al 5 (Fe,Mn)Si phase dissolved partially in Sr-modified alloys, and its dissolution became more pronounced after solution heat treatment. At 0.5% Mn, the β-Fe phase forms when the Fe content is above 0.75%, causing the tensile properties to decrease drastically. The same results are obtained when the levels of both Fe and Mn are increased beyond 0.75%, because of sludge formation. On the other hand, the tensile properties of the Cu-containing alloys are affected slightly at high levels of Mg as a result of the formation of Al 5 Cu 2 Mg 8 Si 6 which decreases the amount of free Mg

  3. The Effects of Al and Ti Additions on the Structural Stability, Mechanical and Electronic Properties of D8m-Structured Ta5Si3

    Directory of Open Access Journals (Sweden)

    Linlin Liu

    2016-05-01

    Full Text Available In the present study, the influence of substitutional elements (Ti and Al on the structural stability, mechanical properties, electronic properties and Debye temperature of Ta5Si3 with a D8m structure were investigated by first principle calculations. The Ta5Si3 alloyed with Ti and Al shows negative values of formation enthalpies, indicating that these compounds are energetically stable. Based on the values of formation enthalpies, Ti exhibits a preferential occupying the Ta4b site and Al has a strong site preference for the Si8h site. From the values of the bulk modulus (B, shear modulus (G and Young’s modulus (E, we determined that both Ti and Al additions decrease both the shear deformation resistance and the elastic stiffness of D8m structured Ta5Si3. Using the shear modulus/bulk modulus ratio (G/B, Poisson’s ratio (υ and Cauchy’s pressure, the effect of Ti and Al additions on the ductility of D8m-structured Ta5Si3 are explored. The results show that Ti and Al additions reduce the hardness, resulting in solid solution softening, but improve the ductility of D8m-structured Ta5Si3. The electronic calculations reveal that Ti and Al additions change hybridization between Ta-Si and Si-Si atoms for the binary D8m-structured Ta5Si3. The new Ta-Al bond is weaker than the Ta-Si covalent bonds, reducing the covalent property of bonding in D8m-structured Ta5Si3, while the new strong Ti4b-Ti4b anti-bonding enhances the metallic behavior of the binary D8m-structured Ta5Si3. The change in the nature of bonding can well explain the improved ductility of D8m-structured Ta5Si3 doped by Ti and Al. Moreover, the Debye temperatures, ΘD, of D8m-structured Ta5Si3 alloying with Ti and Al are decreased as compared to the binary Ta5Si3.

  4. Promoting Effect of CeO2 Addition on Activity and Catalytic Stability in Steam Reforming of Methane over Ni/Al2O3

    International Nuclear Information System (INIS)

    Rakib, A.; Gennequin, C.; Ringot, S.; Aboukais, A.; Abi-Aad, E.; Dhainaut, T.

    2011-01-01

    Hydrogen production by steam reforming of methane was studied over Ni catalysts supported on CeO 2 , Al 2 O 3 and CeO 2 -Al 2 O 3 . These catalysts were prepared using the impregnation method and characterized by XRD. The effect of CeO2 promoter on the catalytic performance of Ni/Al 2 O 3 catalyst for methane steam reforming reaction was investigated. In fact, CeO 2 had a positive effect on the catalytic activity in this reaction. Experimental results demonstrated that Ni/CeO 2 -Al 2 O 3 catalyst showed excellent catalytic activity and high reaction performance. In addition, the effects of reaction temperature and metal content on the conversion of CH 4 and H 2 /CO ratio were also investigated. Results indicated that CH4 conversion increased significantly with the increase of the reaction temperature and metal content. (author)

  5. On the Chemical Signature and Origin of Dicoppertrihydroxyformate (Cu2(OH)3HCOO) Formed on Copper Miniatures of 17th and 18th centuries.

    Science.gov (United States)

    Veiga, Alfredina; Teixeira, Dora Martins; Candeias, António J; Mirão, José; Rodrigues, Paulo Simões; Teixeira, Jorge Ginja

    2016-10-01

    A corrosion product rarely reported in the literature has been found on the copper support of three miniature paintings of the 17th and 18th centuries. This product, which has been identified as dicoppertrihydroxyformate (Cu2(OH)3HCOO), is an unusual basic copper formate found on copper artifacts. The identification and characterization of dicoppertrihydroxyformate was carried out directly over the corroded surface of the objects, using a nondestructive approach, which combines the integrated use of various microanalytical techniques. Using this approach, it was possible to obtain a set of new reference data about the natural form of Cu2(OH)3HCOO, that will enable its unambiguous identification in other similar objects. In this work, the probable causes that may have contributed to its formation are also discussed.

  6. Evaluation of liquid-phase sintering SiC using as additive the system Al2O3/DyO3

    International Nuclear Information System (INIS)

    Oliveira, M.R.; Atilio, I.; Garcia, G.C.R.; Ribeiro, S.

    2012-01-01

    The objective of this work was to study the liquid-phase sintering SiC with additives that has not been studied yet, Al 2 O 3 /Dy 2 O 3 , with 10% in volume. The powders were mixed, dried, and pressed in uniaxial and isostatic pressing. It was studied the melting temperature of the additives and bars were sintered at temperatures of 1900, 1950 e 2000 deg C, with averaged linear shrinkage of 17%, phase transformations of β-SiC into α-SiC and formation of Dy 3 Al 5 O 12 at all temperatures. The results showed that for further densification, the temperature of 1950 deg C is enough for a higher densification, with a low wetting angle, transformations of SiC and formation of Dy 3 Al 5 O 12 . (author)

  7. The influence of additions of Al and Si on the lattice stability of fcc and hcp Fe-Mn random alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gebhardt, T; Music, D; Schneider, J M [Materials Chemistry, RWTH Aachen University, D-52056 Aachen (Germany); Ekholm, M; Abrikosov, I A [Department of Physics, Chemistry and Biology (IFM), Linkoeping University, SE-58183 Linkoeping (Sweden); Vitos, L [Department of Materials and Engineering, Applied Materials Physics, Royal Institute of Technology (KTH), SE-10044 Stockholm (Sweden); Dick, A; Hickel, T; Neugebauer, J, E-mail: gebhardt@mch.rwth-aachen.de [Department of Computational Materials Design, Max-Planck-Institut fuer Eisenforschung GmbH, D-40237 Duesseldorf (Germany)

    2011-06-22

    We have studied the influence of additions of Al and Si on the lattice stability of face-centred-cubic (fcc) versus hexagonal-closed-packed (hcp) Fe-Mn random alloys, considering the influence of magnetism below and above the fcc Neel temperature. Employing two different ab initio approaches with respect to basis sets and treatment of magnetic and chemical disorder, we are able to quantify the predictive power of the ab initio methods. We find that the addition of Al strongly stabilizes the fcc lattice independent of the regarded magnetic states. For Si a much stronger dependence on magnetism is observed. Compared to Al, almost no volume change is observed as Si is added to Fe-Mn, indicating that the electronic contributions are responsible for stabilization/destabilization of the fcc phase.

  8. The influence of additions of Al and Si on the lattice stability of fcc and hcp Fe-Mn random alloys

    International Nuclear Information System (INIS)

    Gebhardt, T; Music, D; Schneider, J M; Ekholm, M; Abrikosov, I A; Vitos, L; Dick, A; Hickel, T; Neugebauer, J

    2011-01-01

    We have studied the influence of additions of Al and Si on the lattice stability of face-centred-cubic (fcc) versus hexagonal-closed-packed (hcp) Fe-Mn random alloys, considering the influence of magnetism below and above the fcc Neel temperature. Employing two different ab initio approaches with respect to basis sets and treatment of magnetic and chemical disorder, we are able to quantify the predictive power of the ab initio methods. We find that the addition of Al strongly stabilizes the fcc lattice independent of the regarded magnetic states. For Si a much stronger dependence on magnetism is observed. Compared to Al, almost no volume change is observed as Si is added to Fe-Mn, indicating that the electronic contributions are responsible for stabilization/destabilization of the fcc phase.

  9. Effect of iron addition on the work-hardening characteristics of Al-16 wt%Ag alloy

    International Nuclear Information System (INIS)

    Abd El-Salam, F.; Mahmoud, M.A.; Abd El-Khalek, A.M.; Nada, R.H.

    2002-01-01

    The effect of pre-aging time (up to 120 min) and temperatures (428-498 K) on the stress-strain characteristics of Al-16 wt%Ag and Al-16 wt%Ag-0.28 wt%Fe alloys was investigated at different deformation temperatures in the range 353-413 K. The tensile parameters measured for both alloys showed general increase with increasing pre-aging time at 428 and 458 K, while the samples pre-aged at 498 K showed initial softening up to pre-aging time of 60 min followed by increased hardening for longer pre-aging times. The Fe-free samples were generally harder than the ternary samples. The activation energy of the fracture mechanism in both alloys was around 28 kJ/mol

  10. THE INFLUENCES OF Fe(III ION and Fe(OH3 COLLOID ON THE PHOTODEGRADATION of p-CHLOROPHENOL CATALYZED BY TiO2

    Directory of Open Access Journals (Sweden)

    Endang Tri Wahyuni

    2010-06-01

    Full Text Available The influences of ionic Fe(III and colloidal Fe(OH3 on the effectiveness of p-chlorophenol photodegradation catalyzed by TiO2 has been studied. Photodegradation was carried out in a batch system by irradiating a suspension of TiO2, p-chlorophenol, and Fe(III as ionic or colloidal forms, using UV lamp for a period of time accompanied by magnetic stirring. Concentration of photodegraded p-chlorophenol was calculated by subtracting the initial concentration with that of undegraded p-chlorophenol. Concentration of undegraded p-chlorophenol was determined by gas chromatography. In this study, TiO2 mass and the photodegradation time were optimized. The influences of concentration of Fe(III solution, mass of Fe(OH3, and pH of the solution have also been systematically studied. The research results showed that the presence of Fe(III ions improved the effectiveness of photocatalytical degradation of p-chlorophenol, which was proportional to the concentrations of Fe(III ion. In contrast, the increasing mass of Fe(OH3 led to a decrease in the degree of p-chlorophenol photodegradation. Furthermore, it was observed that increasing pH of the solution resulted in a decrease in the photodegradation of p-chlorophenol. This phenomena may be due to the different species of TiO2 available at the surface of photocatalyst and of ionic Fe(III and colloidal Fe(OH3 in the solution resulted from the pH alteration. The highest photodegradation degree, ca. 80 % was obtained when 20 mg of TiO2 was applied in the photodegradation of 50 mL of 100 ppm p-chlorophenol solution in the presence of 100 ppm Fe3+ irradiated by UV-light for 25 hours.    Keywords: p-chlorophenol photodegradation, TiO2, Fe(III species

  11. The Effect of Al2O3 Addition on the Thermal Diffusivity of Heat Activated Acrylic Resin.

    Science.gov (United States)

    Atla, Jyothi; Manne, Prakash; Gopinadh, A; Sampath, Anche; Muvva, Suresh Babu; Kishore, Krishna; Sandeep, Chiramana; Chittamsetty, Harika

    2013-08-01

    This study aimed at investigating the effect of adding 5% to 20% by weight aluminium oxide powder (Al2O3) on thermal diffusivity of heat-polymerized acrylic resin. Twenty five cylindrical test specimens with an embedded thermocouple were used to determine thermal diffusivity over a physiologic temperature range (0 to 70°C). The specimens were divided into five groups (5 specimens/group) which were coded A to E. Group A was the control group (unmodified acrylic resin specimens). The specimens of the remaining four groups were reinforced with 5%, 10%, 15%, and 20% Al2O3 by weight. RESULTS were analysed by using one-way analysis of variance (ANOVA). Test specimens which belonged to Group E showed the highest mean thermal diffusivity value of 10.7mm(2)/sec, followed by D (9.09mm(2)/sec), C (8.49mm(2)/sec), B(8.28mm(2)/sec) and A(6.48mm(2)/sec) groups respectively. Thermal diffusivities of the reinforced acrylic resins were found to be significantly higher than that of the unmodified acrylic resin. Thermal diffusivity was found to increase in proportion to the weight percentage of alumina filler. Al2O3 fillers have potential to provide increased thermal diffusivity. Increasing the heat transfer characteristics of the acrylic resin base material could lead to more patient satisfaction.

  12. The effects of small metal additions (Co, Cu, Ga, Mn, Al, Bi, Sn) on the magnetocaloric properties of the Gd5Ge2Si2 alloy

    Czech Academy of Sciences Publication Activity Database

    Shull, R. D.; Provenzano, V.; Shapiro, A. J.; Fu, A.; Lufaso, M. W.; Karapetrova, J.; Kletetschka, Günther; Mikula, V.

    2006-01-01

    Roč. 99, č. 8 (2006), s. 8-8 ISSN 0021-8979 Institutional research plan: CEZ:AV0Z30130516 Keywords : magnetocaloric * (Co, Cu, Ga, Mn, Al, Bi, Sn) additions * Cryogenic properties Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.316, year: 2006

  13. Synthesis and structure of a 1,6-hexyldiamine heptaborate, [H3N(CH2)6NH3][B7O10(OH)3

    International Nuclear Information System (INIS)

    Yang Sihai; Li Guobao; Tian Shujian; Liao Fuhui; Xiong Ming; Lin Jianhua

    2007-01-01

    A new 1,6-hexyldiamine heptaborate, [H 3 N(CH 2 ) 6 NH 3 ][B 7 O 10 (OH) 3 ] (1), has been solvothermally synthesized and characterized by single-crystal X-ray diffraction, FTIR, elemental analysis, and thermogravimetric analysis. Compound 1 crystallizes in monoclinic system, space group P2 1 /n with a=8.042(2) A, b=20.004(4) A, c=10.103(2) A, and β=90.42(3) deg. The anionic [B 7 O 10 (OH) 3 ] n 2n- layers are interlinked via hydrogen bonding to form a 3D supramolecular network containing large channels, in which the templated [H 3 N(CH 2 ) 6 NH 3 ] 2+ cations are located. - Graphical abstract: A layered 1,6-hexyldiamine heptaborate, [H 3 N(CH 2 ) 6 NH 3 ][B 7 O 10 (OH) 3 ], was solvothermally synthesized at 150 deg. C. It is a layer borate and crystallized in monoclinic space group P2 1 /n with a=8.042(2) A, b=20.004(4) A, c=10.103(2) A, β=90.42(3) deg

  14. Thermo-Exfoliated Graphite Containing CuO/Cu2(OH3NO3:(Co2+/Fe3+ Composites: Preparation, Characterization and Catalytic Performance in CO Conversion

    Directory of Open Access Journals (Sweden)

    Vladyslav V. Lisnyak

    2010-01-01

    Full Text Available Thermo-exfoliated graphite (TEG/CuO/Cu2(OH3NO3:(Co2+/Fe3+ composites were prepared using a wet impregnation method and subsequent thermal treatment. The physicochemical characterization of the composites was carried out by powder X-ray diffraction (PXRD, scanning electron microscopy (SEM and Ar temperature-desorption techniques. The catalytic efficiency toward CO conversion to CO2 was examined under atmospheric pressure. Characterization of species adsorbed over the composites taken after the activity tests were performed by means of temperature programmed desorption massspectrometry (TPD MS. (TEG/CuO/Cu2(OH3NO3:(Co2+/Fe3+ composites show superior performance results if lower temperatures and extra treatment with H2SO4 or HNO3 are used at the preparation stages. The catalytic properties enhancements can be related to the Cu2(OH3NO3 phase providing reaction centers for the CO conversion. It has been found that prevalence of low-temperature states of desorbed CO2 over high-temperature ones in the TPD MS spectra is characteristic of the most active composite catalysts.

  15. Improving High-Temperature Tensile and Low-Cycle Fatigue Behavior of Al-Si-Cu-Mg Alloys Through Micro-additions of Ti, V, and Zr

    Science.gov (United States)

    Shaha, S. K.; Czerwinski, F.; Kasprzak, W.; Friedman, J.; Chen, D. L.

    2015-07-01

    High-temperature tensile and low-cycle fatigue tests were performed to assess the influence of micro-additions of Ti, V, and Zr on the improvement of the Al-7Si-1Cu-0.5Mg (wt pct) alloy in the as-cast condition. Addition of transition metals led to modification of microstructure where in addition to conventional phases present in the Al-7Si-1Cu-0.5Mg base, new thermally stable micro-sized Zr-Ti-V-rich phases Al21.4Si4.1Ti3.5VZr3.9, Al6.7Si1.2TiZr1.8, Al2.8Si3.8V1.6Zr, and Al5.1Si35.4Ti1.6Zr5.7Fe were formed. The tensile tests showed that with increasing test temperature from 298 K to 673 K (25 °C to 400 °C), the yield stress and tensile strength of the present studied alloy decreased from 161 to 84 MPa and from 261 to 102 MPa, respectively. Also, the studied alloy exhibited 18, 12, and 5 pct higher tensile strength than the alloy A356, 354 and existing Al-Si-Cu-Mg alloy modified with additions of Zr, Ti, and Ni, respectively. The fatigue life of the studied alloy was substantially longer than those of the reference alloys A356 and the same Al-7Si-1Cu-0.5Mg base with minor additions of V, Zr, and Ti in the T6 condition. Fractographic analysis after tensile tests revealed that at the lower temperature up to 473 K (200 °C), the cleavage-type brittle fracture for the precipitates and ductile fracture for the matrix were dominant while at higher temperature fully ductile-type fracture with debonding and pull-out of cracked particles was identified. It is believed that the intermetallic precipitates containing Zr, Ti, and V improve the alloy performance at increased temperatures.

  16. Dehydrogenation of Surface-Oxidized Mixtures of 2LiBH4 + Al/Additives (TiF3 or CeO2

    Directory of Open Access Journals (Sweden)

    Juan Luis Carrillo-Bucio

    2017-11-01

    Full Text Available Research for suitable hydrogen storage materials is an important ongoing subject. LiBH4–Al mixtures could be attractive; however, several issues must be solved. Here, the dehydrogenation reactions of surface-oxidized 2LiBH4 + Al mixtures plus an additive (TiF3 or CeO2 at two different pressures are presented. The mixtures were produced by mechanical milling and handled under welding-grade argon. The dehydrogenation reactions were studied by means of temperature programmed desorption (TPD at 400 °C and at 3 or 5 bar initial hydrogen pressure. The milled and dehydrogenated materials were characterized by scanning electron microscopy (SEM, X-ray diffraction (XRD, and Fourier transformed infrared spectroscopy (FT-IR The additives and the surface oxidation, promoted by the impurities in the welding-grade argon, induced a reduction in the dehydrogenation temperature and an increase in the reaction kinetics, as compared to pure (reported LiBH4. The dehydrogenation reactions were observed to take place in two main steps, with onsets at 100 °C and 200–300 °C. The maximum released hydrogen was 9.3 wt % in the 2LiBH4 + Al/TiF3 material, and 7.9 wt % in the 2LiBH4 + Al/CeO2 material. Formation of CeB6 after dehydrogenation of 2LiBH4 + Al/CeO2 was confirmed.

  17. Adsorption of tetracycline on Fe (hydr)oxides: effects of pH and metal cation (Cu2+, Zn2+ and Al3+) addition in various molar ratios

    Science.gov (United States)

    Hsu, Liang-Ching; Liu, Yu-Ting; Syu, Chien-Hui; Huang, Mei-Hsia; Teah, Heng Yi

    2018-01-01

    Iron (Fe) (hydr)oxides control the mobility and bioavailability of tetracycline (TC) in waters and soils. Adsorption of TC on Fe (hydr)oxides is greatly affected by polyvalent metals; however, impacts of molar metal/TC ratios on TC adsorptive behaviours on Fe (hydr)oxides remain unclear. Results showed that maximum TC adsorption on ferrihydrite and goethite occurred at pH 5–6. Such TC adsorption was generally promoted by the addition of Cu2+, Zn2+ and Al3+. The greatest increase in TC adsorption was found in the system with molar Cu/TC ratio of 3 due to the formation of Fe hydr(oxide)–Cu–TC ternary complexes. Functional groups on TC that were responsible for the complexation with Cu2+shifted from phenolic diketone groups at Cu/TC molar ratio adsorption at a molar Al/TC ratio of 1. However, TC adsorption decreased for Al/TC molar ratio > 1 as excess Al3+ led to the competitive adsorption with Al/TC complexes. For the Zn2+ addition, no significant correlation was found between TC adsorption capacity and molar Zn/TC ratios. PMID:29657795

  18. Morphology, microstructure, and hardness of titanium (Ti-6Al-4V) blocks deposited by wire-feed additive layer manufacturing (ALM)

    International Nuclear Information System (INIS)

    Brandl, Erhard; Schoberth, Achim; Leyens, Christoph

    2012-01-01

    Highlights: ► The microstructure and hardness of deposited Ti-6Al-4V blocks are investigated. ► Hardness is influenced by post heat treatment rather than by process parameters. ► Microstructure within the prior β-grains varies to some extent from grain to grain. ► A 600 °C/4 h treatment significantly increased the average hardness. - Abstract: Additive layer manufacturing offers a potential for time and cost savings, especially for aerospace components made from costly titanium alloys. In this paper, the morphology, microstructure, chemical composition, and hardness of additive manufactured Ti-6Al-4V blocks are investigated and discussed. Blocks (7 beads wide, 7 layers high) were deposited using Ti-6Al-4V wire and a Nd:YAG laser. Two different sets of parameters are used and three different post heat treatment conditions (as-built, 600 °C/4 h, 1200 °C/2 h) are investigated. The experiments reveal elementary properties of additive manufactured Ti-6Al-4V material in correlation to process parameters and heat treatments, which are discussed comprehensively.

  19. Morphology, microstructure, and hardness of titanium (Ti-6Al-4V) blocks deposited by wire-feed additive layer manufacturing (ALM)

    Energy Technology Data Exchange (ETDEWEB)

    Brandl, Erhard, E-mail: erhard.brandl@eads.net [EADS Innovation Works, Metallic Technologies and Surface Engineering, D-81663 Munich (Germany); Schoberth, Achim, E-mail: achim.schoberth@eads.net [EADS Innovation Works, Metallic Technologies and Surface Engineering, D-81663 Munich (Germany); Leyens, Christoph, E-mail: christoph.leyens@tu-dresden.de [Technical University of Dresden, Institute of Materials Science, Chair of Materials Technology, Berndt-Bau, Helmholtzstr. 7, D-01062 Dresden (Germany)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer The microstructure and hardness of deposited Ti-6Al-4V blocks are investigated. Black-Right-Pointing-Pointer Hardness is influenced by post heat treatment rather than by process parameters. Black-Right-Pointing-Pointer Microstructure within the prior {beta}-grains varies to some extent from grain to grain. Black-Right-Pointing-Pointer A 600 Degree-Sign C/4 h treatment significantly increased the average hardness. - Abstract: Additive layer manufacturing offers a potential for time and cost savings, especially for aerospace components made from costly titanium alloys. In this paper, the morphology, microstructure, chemical composition, and hardness of additive manufactured Ti-6Al-4V blocks are investigated and discussed. Blocks (7 beads wide, 7 layers high) were deposited using Ti-6Al-4V wire and a Nd:YAG laser. Two different sets of parameters are used and three different post heat treatment conditions (as-built, 600 Degree-Sign C/4 h, 1200 Degree-Sign C/2 h) are investigated. The experiments reveal elementary properties of additive manufactured Ti-6Al-4V material in correlation to process parameters and heat treatments, which are discussed comprehensively.

  20. Reduction of tobacco smoke components yield in commercial cigarette brands by addition of HUSY, NaY and Al-MCM-41 to the cigarette rod.

    Science.gov (United States)

    Marcilla, A; Gómez-Siurana, A; Berenguer, D; Martínez-Castellanos, I; Beltrán, M I

    2015-01-01

    The effect of two zeolites, HUSY, NaY and a mesoporous synthesized Al-MCM-41 material on the smoke composition of ten commercial cigarettes brands has been studied. Cigarettes were prepared by mixing the tobacco with the three powdered materials, and the smoke obtained under the ISO conditions was analyzed. Up to 32 compounds were identified and quantified in the gas fraction and 80 in the total particulate matter (TPM) condensed in the cigarettes filters and in the traps located after the mouth end of the cigarettes. Al-MCM-41 is by far the best additive, providing the highest reductions of the yield for most compounds and brands analyzed. A positive correlation was observed among the TPM and nicotine yields with the reduction obtained in nicotine, CO, and most compounds with the three additives. The amount of ashes in additive free basis increases due to the coke deposited on the solids, especially with Al-MCM-41. Nicotine is reduced with Al-MCM-41 by an average of 34.4% for the brands studied (49.5% for the brand where the major reduction was obtained and 18.5 for the brand behaving the worst). CO is reduced by an average of 18.6% (ranging from 10.3 to 35.2% in the different brands).

  1. Reduction of tobacco smoke components yield in commercial cigarette brands by addition of HUSY, NaY and Al-MCM-41 to the cigarette rod

    Directory of Open Access Journals (Sweden)

    A. Marcilla

    2015-01-01

    Full Text Available The effect of two zeolites, HUSY, NaY and a mesoporous synthesized Al-MCM-41 material on the smoke composition of ten commercial cigarettes brands has been studied. Cigarettes were prepared by mixing the tobacco with the three powdered materials, and the smoke obtained under the ISO conditions was analyzed. Up to 32 compounds were identified and quantified in the gas fraction and 80 in the total particulate matter (TPM condensed in the cigarettes filters and in the traps located after the mouth end of the cigarettes. Al-MCM-41 is by far the best additive, providing the highest reductions of the yield for most compounds and brands analyzed. A positive correlation was observed among the TPM and nicotine yields with the reduction obtained in nicotine, CO, and most compounds with the three additives. The amount of ashes in additive free basis increases due to the coke deposited on the solids, especially with Al-MCM-41. Nicotine is reduced with Al-MCM-41 by an average of 34.4% for the brands studied (49.5% for the brand where the major reduction was obtained and 18.5 for the brand behaving the worst. CO is reduced by an average of 18.6% (ranging from 10.3 to 35.2% in the different brands.

  2. Reply to comment on 'Formation and characterization of nanotubes of La(OH)3 obtained using porous alumina membranes'

    International Nuclear Information System (INIS)

    Gonzalez-Rovira, L; Sanchez-Amaya, J M; Boukha, Z; Botana, F J; Lopez-Haro, M; Hungria, A B; Bernal, S

    2010-01-01

    The authors are grateful for the opportunity to reply to the comments on our previous contribution (Gonzalez-Rovira et al 2008 Nanotechnology 18 495305). We would like to clarify some aspects regarding the aim of our studies along with the morphological, chemical and structural features of the nanomaterials synthesized. (reply)

  3. Furfural and other furane-derivates as diesel fuel additives. Furfural und andere Furanderivate als Zusatz zum Dieselkraftstoff

    Energy Technology Data Exchange (ETDEWEB)

    Nemling, O.

    1982-01-01

    Alternative energies such as fuel additives or fuel-substitutes are on their way upwards as they may help to reduce the dependency on crude and crude-based fuels. A number of solutions has already been indicated for carburettor engines whereas a lot more of research and development is needed to find a safe alternative to diesel fuels. Possibilities of using furfural, furfuralcohol and furan-2-carbonic acid-methylester as additives to diesel or as a substitute were investigated. A survey on the characteristic properties of these substances is given, then several tests are set up in order to describe the properties of diesel additive mixtures at low temperatures. Based on these tests two mixtures are proposed both with a furfural/butanole mixture. Furfural is suitable as diesel additive, a solubilizer is needed though.

  4. Effect of surface roughness on the fatigue life of laser additive manufactured Ti6Al4V alloy

    Czech Academy of Sciences Publication Activity Database

    Bača, A.; Konečná, R.; Nicoletto, G.; Kunz, Ludvík

    2015-01-01

    Roč. 15, č. 4 (2015), s. 498-502 ISSN 1213-2489 Institutional support: RVO:68081723 Keywords : Additive manufacturing * direct metal laser sintering * Fatigue life Subject RIV: JL - Materials Fatigue, Friction Mechanics

  5. Development of sensitisation or tolerance following repeated OVA inhalation in BALB/cJ mice. Dose-dependency and modulation by the Al(OH)3 adjuvant

    DEFF Research Database (Denmark)

    Clausen, Susanne Knoth; Bergqvist, Mette; Poulsen, Lars K.

    2003-01-01

    Anthropogenically induced exposures may, due to their adjuvant effect, promote development of sensitisation to commonly occurring aeroallergens. No generally accepted model exists for determination of adjuvant effect of airborne substances. Therefore, BALB/cJ mice were exposed for 10 consecutive...

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

    Directory of Open Access Journals (Sweden)

    Richtárech L.

    2015-06-01

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

  7. Corrosion behavior of Fe3Al intermetallics with addition of lithium, cerium and nickel in 2.5 % SO2+N2 at 900 degree centigrade

    International Nuclear Information System (INIS)

    Luna-Ramirez, A.; Porcayo-Calderon, J.; Martinez-Villafane, A.; Gonzalez-Rodriguez, J. G.; Chaon-Nava, J. G.

    2012-01-01

    The corrosion behavior of Fe 3 Al-type intermetallic alloys with addition of 1 at. % cerium, lithium and nickel at high temperature has been studied. The various alloys were exposed to an environment composed of 2.5 % SO 2 +N 2 at 900 degree centigrade for 48 h. For all the intermetallic tested, the corrosion kinetics showed a parabolic behavior. The alloy, which showed less corrosion rate, was the Fe3AlNi alloy, being Fe 3 AlCeLi the alloy with the highest corrosion rate. For the various alloys, energy dispersive X-ray spectroscopy analysis, EDS, on the developed scale only detected aluminum, oxygen, and traces of iron and cerium, suggesting the formation of alumina as main component. The intermetallic alloys showed oxide cracking and spalling. The intermetallic chemical composition played an important role in defining the oxide scale morphology and the extent of damage. (Author) 39 refs.

  8. Effect of titanium and calcium oxide additions on Zr2O2 polymorphism during Al2O3+Zr2O2 mixture fusion

    International Nuclear Information System (INIS)

    Gladkov, V.E.; Zhekhanova, N.B.; Fotiev, A.A.; Viktorov, V.V.; Ivashinnikov, V.T.; Zubov, A.S.

    1985-01-01

    The effect of titanium and calcium containing additions introduced into the Al 2 O 3 +ZrO 2 melt on the phase composition and temperature ranges of ZrO 2 polymorphous transformation in the material is investigated. It is shown that introducing sponge titanium into the 70Al 2 O 3 +30ZrO 2 prepared composition melt (mass. %) with its subsequent intensive cooling one can conserve upto room temperatures 50-70% of ZrO 2 metastable tetragonal modification and therefore reduce the volume changes causing metal cracking. Calcium oxide doping stabilizes the ZrO 2 cubic modification and reduces α-Al 2 O 3 content due to formation of aluminates

  9. Analysis of the co-deposition of Al2O3 particles with nickel by an electrolytic route: The influence of organic additives presence and Al2O3 concentration

    Science.gov (United States)

    Temam, H. B.; Temam, E. G.

    2016-04-01

    Alloy coatings were prepared by co-deposition of Al2O3 particles in Ni matrix on carbon steel substrate from nickel chloride bath in which metallic powders were held in suspension. The influence of metal powder amount in the bath on chemical composition, morphology, thickness, microhardness and corrosion behavior of obtained coatings, has been investigated. It was shown that the presence of Al2O3 particles in deposit greatly improves the hardness and the wear resistance of alloy coatings. Characterization by microanalysis (EDX) of the various deposits elaborated confirms that the rate of particles incorporated increases as the concentration of solid particles increasing. The results showed that the presence of organic additives in Ni-Al2O3 electrolyte deposition led to an increase in the hardness and corrosion resistance of the deposits.

  10. Heterogeneous coarsening of Pb phase and the effect of Cu addition on it in a nanophase composite of Al-10 wt%Pb alloy prepared by mechanical alloying

    International Nuclear Information System (INIS)

    Zhu, M.; Liu, X.; Wu, Z.F.; Ouyang, L.Z.; Zeng, M.Q.

    2009-01-01

    A nanophase composite of Al-10 wt%Pb alloy was prepared by mechanical alloying. The coarsening behavior of Pb phase in the composite during heating process was investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and nanoindentation test. The present work shows that the Pb phase grew substantially and had two different size distributions when the heating temperature was above 823 K. The different size distributions of Pb phase were owing to different grain size ranges of Al matrix in different regions, which led to the different growth rates of the Pb phase in those regions. It has been proposed that the different size ranges of Al grain appeared upon heating were originated from a statistical size distribution of Al grains in the as-milled powder. With the addition of a small amount of Cu, the heterogeneous growth of Pb phase can be suppressed, and the coarsening of Pb phase shows two distinct rates. This indicates that the coarsening is mainly governed by grain boundary diffusion and lattice diffusion of Al matrix in the initial stage and the later one, respectively

  11. Effect of Al_2O_3 Nanoparticles Additives on the Density, Saturated Vapor Pressure, Surface Tension and Viscosity of Isopropyl Alcohol

    Science.gov (United States)

    Zhelezny, Vitaly; Geller, Vladimir; Semenyuk, Yury; Nikulin, Artem; Lukianov, Nikolai; Lozovsky, Taras; Shymchuk, Mykola

    2018-03-01

    This paper presents results of an experimental study of the density, saturated vapor pressure, surface tension and viscosity of Al_2O_3 nanoparticle colloidal solutions in isopropyl alcohol. Studies of the thermophysical properties of nanofluids were performed at various temperatures and concentrations of Al_2O_3 nanoparticles. The paper gives considerable attention to a turbidimetric analysis of the stability of nanofluid samples. Samples of nanofluids remained stable over the range of parameters of the experiments, ensuring the reliability of the thermophysical property data for the Al_2O_3 nanoparticle colloidal solutions in isopropyl alcohol. The studies show that the addition of Al_2O_3 nanoparticles leads to an increase of the density, saturated vapor pressure and viscosity, as well as a decrease for the surface tension of isopropyl alcohol. The information reported in this paper on the various thermophysical properties for the isopropyl alcohol/Al_2O_3 nanoparticle model system is useful for the development of thermodynamically consistent models for predicting properties of nanofluids and correct modeling of the heat exchange processes.

  12. TEM and HRTEM study of oxide particles in an Al-alloyed high-Cr oxide dispersion strengthened ferritic steel with Hf addition

    Energy Technology Data Exchange (ETDEWEB)

    Dou, Peng, E-mail: doup@tsinghua.edu.cn [School of Materials Science and Engineering, Chongqing University, Chongqing 400044 (China); Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Kimura, Akihiko, E-mail: kimura@iae.kyoto-u.ac.jp [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Kasada, Ryuta, E-mail: r-kasada@iae.kyoto-u.ac.jp [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Okuda, Takanari, E-mail: okuda.takanari@kki.kobelco.com [Kobelco Research Institute, 1-5-5 Takatsukadai, Nishi-ku, Kobe, Hyogo 651-2271 (Japan); Inoue, Masaki, E-mail: inoue.masaki@jaea.go.jp [Advanced Nuclear System R& D Directorate, Japan Atomic Energy Agency, 4002 Narita, O-arai, Ibaraki 311-1393 (Japan); Ukai, Shigeharu, E-mail: s-ukai@eng.hokudai.ac.jp [Graduate School of Engineering, Hokkaido University, N13, W8, Kita-ku, Sapporo 060-8628 (Japan); Ohnuki, Somei, E-mail: ohnuki@eng.hokudai.ac.jp [Graduate School of Engineering, Hokkaido University, N13, W8, Kita-ku, Sapporo 060-8628 (Japan); Fujisawa, Toshiharu, E-mail: fujisawa@esi.nagoya-u.ac.jp [EcoTopia Science Institute, Nagoya University, Furo, Chikusa-ku, Nagoya 464-8603 (Japan); Abe, Fujio, E-mail: ABE.Fujio@nims.go.jp [Structural Metals Center, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Jiang, Shan, E-mail: js93518@gmail.com [School of Materials Science and Engineering, Chongqing University, Chongqing 400044 (China); Yang, Zhigang, E-mail: zgyang@tsinghua.edu.cn [Key Laboratory of Advanced Materials (MOE), School of Materials Sciences and Engineering, Tsinghua University, Beijing 100084 (China)

    2017-03-15

    The nanoparticles in an Al-alloyed high-Cr oxide dispersion strengthened (ODS) ferritic steel with Hf addition, i.e., SOC-16 (Fe-15Cr-2W-0.1Ti-4Al-0.62Hf-0.35Y{sub 2}O{sub 3}), have been examined by transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). Relative to an Al-alloyed high-Cr ODS ferritic steel without Hf addition, i.e., SOC-9 (Fe-15.5Cr-2W-0.1Ti-4Al-0.35Y{sub 2}O{sub 3}), the dispersion morphology and coherency of the oxide nanoparticles in SOC-16 were significantly improved. Almost all the small nanoparticles (diameter <10 nm) in SOC-16 were found to be consistent with cubic Y{sub 2}Hf{sub 2}O{sub 7} oxides with the anion-deficient fluorite structure and coherent with the bcc steel matrix. The larger particles (diameter >10 nm) were also mainly identified as cubic Y{sub 2}Hf{sub 2}O{sub 7} oxides with the anion-deficient fluorite structure. The results presented here are compared with those of SOC-9 with a brief discussion of the underlying mechanisms of the unusual thermal and irradiation stabilities of the oxides as well as the superior strength, excellent irradiation tolerance and extraordinary corrosion resistance of SOC-16.

  13. Inhibition of ammonia poisoning by addition of platinum to Ru/α-Al2 O3 for preferential CO oxidation in fuel cells.

    Science.gov (United States)

    Sato, Katsutoshi; Yagi, Sho; Zaitsu, Shuhei; Kitayama, Godai; Kayada, Yuto; Teramura, Kentaro; Takita, Yusaku; Nagaoka, Katsutoshi

    2014-12-01

    In polymer electrolyte fuel cell (PEFC) systems, small amounts of ammonia (NH3 ) present in the reformate gas deactivate the supported ruthenium catalysts used for preferential oxidation (PROX) of carbon monoxide (CO). In this study, we investigated how the addition of a small amount of platinum to a Ru/α-Al2 O3 catalyst (Pt/Ru=1:9 w/w) affected the catalyst's PROX activity in both the absence and the presence of NH3 (130 ppm) under conditions mimicking the reformate conditions during steam reforming of natural gas. The activity of undoped Ru/α-Al2 O3 decreased sharply upon addition of NH3 , whereas Pt/Ru/α-Al2 O3 exhibited excellent PROX activity even in the presence of NH3 . Ruthenium K-edge X-ray absorption near-edge structure (XANES) spectra indicated that in the presence of NH3 , some of the ruthenium in the undoped catalyst was oxidized in the presence of NH3 , whereas ruthenium oxidation was not observed with Pt/Ru/α-Al2 O3 . These results suggest that ruthenium oxidation is retarded by the platinum, so that the catalyst shows high activity even in the presence of NH3 . © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. TEM and HRTEM study of oxide particles in an Al-alloyed high-Cr oxide dispersion strengthened ferritic steel with Hf addition

    International Nuclear Information System (INIS)

    Dou, Peng; Kimura, Akihiko; Kasada, Ryuta; Okuda, Takanari; Inoue, Masaki; Ukai, Shigeharu; Ohnuki, Somei; Fujisawa, Toshiharu; Abe, Fujio; Jiang, Shan; Yang, Zhigang

    2017-01-01

    The nanoparticles in an Al-alloyed high-Cr oxide dispersion strengthened (ODS) ferritic steel with Hf addition, i.e., SOC-16 (Fe-15Cr-2W-0.1Ti-4Al-0.62Hf-0.35Y 2 O 3 ), have been examined by transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). Relative to an Al-alloyed high-Cr ODS ferritic steel without Hf addition, i.e., SOC-9 (Fe-15.5Cr-2W-0.1Ti-4Al-0.35Y 2 O 3 ), the dispersion morphology and coherency of the oxide nanoparticles in SOC-16 were significantly improved. Almost all the small nanoparticles (diameter <10 nm) in SOC-16 were found to be consistent with cubic Y 2 Hf 2 O 7 oxides with the anion-deficient fluorite structure and coherent with the bcc steel matrix. The larger particles (diameter >10 nm) were also mainly identified as cubic Y 2 Hf 2 O 7 oxides with the anion-deficient fluorite structure. The results presented here are compared with those of SOC-9 with a brief discussion of the underlying mechanisms of the unusual thermal and irradiation stabilities of the oxides as well as the superior strength, excellent irradiation tolerance and extraordinary corrosion resistance of SOC-16.

  15. Influence of Powder Characteristics on Formation of Porosity in Additive Manufacturing of Ti-6Al-4V Components

    Science.gov (United States)

    Iebba, Maurizio; Astarita, Antonello; Mistretta, Daniela; Colonna, Ivano; Liberini, Mariacira; Scherillo, Fabio; Pirozzi, Carmine; Borrelli, Rosario; Franchitti, Stefania; Squillace, Antonino

    2017-08-01

    This paper aims to study the genesis of defects in titanium components made through two different additive manufacturing technologies: selective laser melting and electron beam melting. In particular, we focussed on the influence of the powders used on the formation of porosities and cavities in the manufactured components. A detailed experimental campaign was carried out to characterize the components made through the two additive manufacturing techniques aforementioned and the powders used in the process. It was found that some defects of the final components can be attributed to internal porosities of the powders used in the manufacturing process. These internal porosities are a consequence of the gas atomization process used for the production of the powders themselves. Therefore, the importance of using tailored powders, free from porosities, in order to manufacture components with high mechanical properties is highlighted.

  16. Numerical and experimental study of Ti6Al4V components manufactured using powder bed fusion additive manufacturing

    OpenAIRE

    Zielinski, J.; Mindt, H.-W.; Düchting, J.; Schleifenbaum, J.H.; Megahed, M.

    2017-01-01

    Powder bed fusion additive manufacturing of titanium alloys is an interesting manufacturing route for many applications requiring high material strength combined with geometric complexity. Managing powder bed fusion challenges, including porosity, surface finish, distortions and residual stresses of as-built material, is the key to bringing the advantages of this process to production main stream. This paper discusses the application of experimental and numerical analysis towards optimizing t...

  17. Effects of Ce and Zr addition on microstructure and hardness of Al-Si-Cu-Mg alloy

    International Nuclear Information System (INIS)

    Bevilaqua, William Lemos; Reguly, Afonso; Froehlich, Andre Ronaldo; Stadtlander, Antonio Ricardo

    2016-01-01

    The effects of cerium and zirconium contents (0.3%-0.16%Zr; 0.3%-0.27%Zr e 0.3%-0.36%Zr) to aluminum alloy 354.0 was investigated by microstructural analysis and hardness measurements in as-cast and heat-treated conditions. The macrostructure show an excellent grain refinement for all Ce and Zr contents used. Additionally, the Cu-Ce reaction during solidification changes significantly the age hardening process of modified alloys. (author)

  18. Electron-microscopy studies of NaAlH{sub 4} with TiF{sub 3} additive: hydrogen-cycling effects

    Energy Technology Data Exchange (ETDEWEB)

    Andrei, C.M.; Holmestad, R. [Norwegian University of Science and Technology, Department of Physics, Trondheim (Norway); Walmsley, J.C. [SINTEF Materials and Chemistry, Trondheim (Norway); Brinks, H.W.; Hauback, B.C. [Institute for Energy Technology, P.O. Box 40, Kjeller (Norway); Srinivasan, S.S.; Jensen, C.M. [University of Hawaii, Department of Chemistry, Honolulu, HI (United States)

    2005-02-01

    NaAlH{sub 4} is a promising candidate material for hydrogen storage. Ti additives are effective in reducing the reaction temperatures and improving kinetics. In this work, the microstructure of NaAlH{sub 4} with 2% TiF{sub 3} has been studied in different conditions using a combination of transmission electron microscopy and scanning electron microscopy, both with energy-dispersive spectroscopic X-ray analysis. The effect of the additive on particle and grain size was examined after the initial ball-milling process and after 15 cycles. The additive has an uneven distribution in the sample after ball milling. Selected-area diffraction and high-resolution imaging confirmed the presence of TiF{sub 3}. This phase accounts for most of the Ti in the material at this stage and showed limited mixing with the alanate. The grain size within particles for TiF{sub 3} is larger than for the alanate particles. Diffraction from the latter was dominated by metallic aluminium. After cycling, the TiF{sub 3} has decomposed and energy-dispersive spectroscopic X-ray analysis maps showed some combination of Ti with the alanate phase. There is no significant change in the measurable grain size of the Al-containing alanate particles between the ball-milled and the 15-cycled samples, but more cycles result in agglomeration of the material. (orig.)

  19. Effect of CuO addition on the sintering temperature and microwave dielectric properties of CaSiO3–Al2O3 ceramics

    Directory of Open Access Journals (Sweden)

    Denghao Li

    2014-06-01

    Full Text Available CuO-doped CaSiO3–1 wt% Al2O3 ceramics were synthesized via a traditional solid-state reaction method, and their sintering behavior, microstructure and microwave dielectric properties were investigated. The results showed that appropriate CuO addition could accelerate the sintering process and assist the densification of CaSiO3–1 wt% Al2O3 ceramics, which could effectively lower the densification temperature from 1250 °C to 1050 °C. However, the addition of CuO undermined the microwave dielectric properties. The optimal amount of CuO addition was found to be 0.8 wt%, and the derived CaSiO3–Al2O3 ceramic sintered at 1100 °C presented good microwave dielectric properties of εr=7.27, Q×f=16,850 GHz and τf=−39.53 ppm/°C, which is much better than those of pure CaSiO3 ceramic sintered at 1340 oC (Q×f=13,109 GHz. The chemical compatibility of the above ceramic with 30 Pd/70 Ag during the cofiring process has also been investigated, and the result showed that there was no chemical reaction between palladium–silver alloys and ceramics.

  20. Variability of OH(3-1) and OH(6-2) emission altitude and volume emission rate from 2003 to 2011

    Science.gov (United States)

    Teiser, Georg; von Savigny, Christian

    2017-08-01

    In this study we report on variability in emission rate and centroid emission altitude of the OH(3-1) and OH(6-2) Meinel bands in the terrestrial nightglow based on spaceborne nightglow measurements with the SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) instrument on the Envisat satellite. The SCIAMACHY observations cover the time period from August 2002 to April 2012 and the nighttime observations used in this study are performed at 10:00 p.m. local solar time. Characterizing variability in OH emission altitude - particularly potential long-term variations - is important for an appropriate interpretation of ground-based OH rotational temperature measurements, because simultaneous observations of the vertical OH volume emission rate profile are usually not available for these measurements. OH emission altitude and vertically integrated emission rate time series with daily resolution for the OH(3-1) band and monthly resolution for the OH(6-2) band were analyzed using a standard multilinear regression approach allowing for seasonal variations, QBO-effects (Quasi-Biennial Oscillation), solar cycle (SC) variability and a linear long-term trend. The analysis focuses on low latitudes, where SCIAMACHY nighttime observations are available all year. The dominant sources of variability for both OH emission rate and altitude are the semi-annual and annual variations, with emission rate and altitude being highly anti-correlated. There is some evidence for a 11-year solar cycle signature in the vertically integrated emission rate and in the centroid emission altitude of both the OH(3-1) and OH(6-2) bands.

  1. UO2-7%Gd2O3 fuel process development by mechanical blending with reprocessing of waste products and usage of densification additive

    International Nuclear Information System (INIS)

    Santos, Lauro Roberto dos

    2009-01-01

    In the nuclear fuel cycle, reprocessing and storage of 'burned' fuels, either temporary or permanent, demand high investments and, in addition, can potentially generate environmental problems. A strategy to decrease these problems is to adopt measures to reduce the amount of waste generated. The usage of integrated burnable poison based on gadolinium is a measure that contributes to achieve this goal. The reason to use burnable poison is to control the neutron population in the reactor during the early life of the fresh reactor core or the beginning of each recharging fuel cycle, extending its cycle duration. Another advantage of using burnable poison is to be able to operate the reactor with higher burning rate, optimizing the usage of the fuel. The process of manufacturing UO 2 -Gd 2 O 3 integrated burnable fuel poison generates waste that, as much as possible, needs to be recycled. Blending of Gd 2 O 3 in UO 2 powder requires the usage of a special additive to achieve the final fuel pellet specified density. The objective of this work is to develop the process of obtaining UO 2 - 7% Gd 2 O 3 integrated burnable poison using densification additives, aluminum hydroxide (Al(OH)3), and reprocessing manufacturing waste products by mechanical blending. The content of 7%- Gd 2 O 3 is based on commercial PWR reactor fuels - Type Angra 2. The results show that the usage of Al(OH) 3 as an additive is a very effective choice that promotes the densification of fuel pellets with recycle up to 10%. Concentrations of 0,20 % of Al(OH) 3 were found to be the indicated amount on an 7 industrial scale, specially when the recycled products come from U 3 O 8 obtained by calcination of sintered pellets. This is particularly interesting because it is following the steps of sintering and rectifying of the pellets, which is generating the largest amounts of recycled material. (author)

  2. UO2-7%Gd2O3 fuel process development by mechanical blending with reprocessing of waste products and usage of densification additive

    International Nuclear Information System (INIS)

    Santos, Lauro Roberto dos

    2009-01-01

    In the nuclear fuel cycle, reprocessing and storage of 'burned' fuels, either temporary or permanent, demand high investments and, in addition, can potentially generate environmental problems. A strategy to decrease these problems is to adopt measures to reduce the amount of waste generated. The usage of integrated burnable poison based on gadolinium is a measure that contributes to achieve this goal. The reason to use burnable poison is to control the neutron population in the reactor during the early life of the fresh reactor core or the beginning of each recharging fuel cycle, extending its cycle duration. Another advantage of using burnable poison is to be able to operate the reactor with higher burning rate, optimizing the usage of the fuel. The process of manufacturing UO 2 -Gd 2 O 3 integrated burnable fuel poison generates waste that, as much as possible, needs to be recycled. Blending of Gd 2 O 3 in UO 2 powder requires the usage of a special additive to achieve the final fuel pellet specified density. The objective of this work is to develop the process of obtaining UO 2 - 7% Gd 2 O 3 integrated burnable poison using densification additives, aluminum hydroxide (Al(OH) 3 ), and reprocessing manufacturing waste products by mechanical blending. The content of 7%- Gd 2 O 3 is based on commercial PWR reactor fuels - Type Angra 2. The results show that the usage of Al(OH) 3 as an additive is a very effective choice that promotes the densification of fuel pellets with recycle up to 10%. Concentrations of 0,20 % of Al(OH) 3 were found to be the indicated amount on an industrial scale, specially when the recycled products come from U 3 O 8 obtained by calcination of sintered pellets. This is particularly interesting because it is following the steps of sintering and rectifying of the pellets, which is generating the largest amounts of recycled material. (author)

  3. Numerical and Experimental Study of Ti6Al4V Components Manufactured Using Powder Bed Fusion Additive Manufacturing

    Science.gov (United States)

    Zielinski, Jonas; Mindt, Hans-Wilfried; Düchting, Jan; Schleifenbaum, Johannes Henrich; Megahed, Mustafa

    2017-12-01

    Powder bed fusion additive manufacturing of titanium alloys is an interesting manufacturing route for many applications requiring high material strength combined with geometric complexity. Managing powder bed fusion challenges, including porosity, surface finish, distortions and residual stresses of as-built material, is the key to bringing the advantages of this process to production main stream. This paper discusses the application of experimental and numerical analysis towards optimizing the manufacturing process of a demonstration component. Powder characterization including assessment of the reusability, assessment of material consolidation and process window optimization is pursued prior to applying the identified optima to study the distortion and residual stresses of the demonstrator. Comparisons of numerical predictions with measurements show good correlations along the complete numerical chain.

  4. Fatigue performance of laser additive manufactured Ti-6Al-4V in very high cycle fatigue (VHCF regime up to 109 cycles

    Directory of Open Access Journals (Sweden)

    Eric eWycisk

    2015-12-01

    Full Text Available Additive manufacturing technologies are in the process of establishing themselves as an alternative production technology to conventional manufacturing such as casting or milling. Especially laser additive manufacturing (LAM enables the production of metallic parts with mechanical properties comparable to conventionally manufactured components. Due to the high geometrical freedom in LAM the technology enables the production of ultra-light weight designs and therefore gains increasing importance in aircraft and space industry. The high quality standards of these industries demand predictability of material properties for static and dynamic load cases. However, fatigue properties especially in the very high cycle fatigue regime until 109 cycles have not been sufficiently determined yet. Therefore this paper presents an analysis of fatigue properties of laser additive manufactured Ti-6Al-4V under cyclic tension-tension until 107 cycles and tension-compression load until 109 cycles.For the analysis of laser additive manufactured titanium alloy Ti-6Al-4V Woehler fatigue tests under tension-tension and tension-compression were carried out in the high cycle and very high cycle fatigue regime. Specimens in stress-relieved as well as hot-isostatic-pressed conditions were analyzed regarding crack initiation site, mean stress sensitivity and overall fatigue performance. The determined fatigue properties show values in the range of conventionally manufactured Ti-6Al-4V with particularly good performance for hot-isostatic-pressed additive-manufactured material. For all conditions the results show no conventional fatigue limit but a constant increase in fatigue life with decreasing loads. No effects of test frequency on life span could be determined. However, independently of testing principle, a shift of crack initiation from surface to internal initiation could be observed with increasing cycles to failure.

  5. In-depth study of the mechanical properties for Fe{sub 3}Al based iron aluminide fabricated using the wire-arc additive manufacturing process

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Chen; Pan, Zengxi, E-mail: zengxi@uow.edu.au; Cuiuri, Dominic; Dong, Bosheng; Li, Huijun

    2016-07-04

    An innovative wire-arc additive manufacturing (WAAM) process is used to fabricate iron aluminide alloy in-situ, through separate feeding of pure Fe and Al wires into a molten pool that is generated by the gas tungsten arc welding (GTAW) process. This paper investigates the morphologies, chemical compositions and mechanical properties of the as-fabricated 30 at% Al iron aluminide wall components, and how these properties vary at different locations within the buildup wall. The tensile properties are also measured in different loading orientations; as epitaxial growth of large columnar grains is observed in the microstructures. Fe{sub 3}Al is the only phase detected in the middle buildup section of the wall structure, which constitutes the majority of the deposited material. The bottom section of the structure contains a dilution affected region where some acicular Fe{sub 3}AlC{sub 0.5} precipitates can be observed, induced by carbon from the steel substrate that was used for fabrication. The microhardness and chemical composition indicate relatively homogeneous material properties throughout the buildup wall. However, the tensile properties are very different in the longitudinal direction and normal directions, due to epitaxial growth of large columnar grains. In general, the results have demonstrated that the WAAM process is capable of producing full density in-situ-alloyed iron aluminide components with tensile properties that are comparable to powder metallurgy methods.

  6. In-depth study of the mechanical properties for Fe_3Al based iron aluminide fabricated using the wire-arc additive manufacturing process

    International Nuclear Information System (INIS)

    Shen, Chen; Pan, Zengxi; Cuiuri, Dominic; Dong, Bosheng; Li, Huijun

    2016-01-01

    An innovative wire-arc additive manufacturing (WAAM) process is used to fabricate iron aluminide alloy in-situ, through separate feeding of pure Fe and Al wires into a molten pool that is generated by the gas tungsten arc welding (GTAW) process. This paper investigates the morphologies, chemical compositions and mechanical properties of the as-fabricated 30 at% Al iron aluminide wall components, and how these properties vary at different locations within the buildup wall. The tensile properties are also measured in different loading orientations; as epitaxial growth of large columnar grains is observed in the microstructures. Fe_3Al is the only phase detected in the middle buildup section of the wall structure, which constitutes the majority of the deposited material. The bottom section of the structure contains a dilution affected region where some acicular Fe_3AlC_0_._5 precipitates can be observed, induced by carbon from the steel substrate that was used for fabrication. The microhardness and chemical composition indicate relatively homogeneous material properties throughout the buildup wall. However, the tensile properties are very different in the longitudinal direction and normal directions, due to epitaxial growth of large columnar grains. In general, the results have demonstrated that the WAAM process is capable of producing full density in-situ-alloyed iron aluminide components with tensile properties that are comparable to powder metallurgy methods.

  7. Bifunctional behavior of Er3+ ions as the sintering additive and the fluorescent agent in Er3+ single doped γ-AlON transparent ceramics

    International Nuclear Information System (INIS)

    Wang, Ying; Xie, Xiumin; Qi, Jianqi; Wang, Shanshan; Wei, Nian; Lu, Zhongwen; Chen, Xingtao; Lu, Tiecheng

    2016-01-01

    We report on the sintering promoting and fluorescent activator roles of Er 3+ in AlON:Er 3+ transparent ceramics prepared by pressureless sintering with Er 2 O 3 and AlON powder. There shows that the transparency of samples varied with the content of Er 2 O 3 additive. The AlON:Er 3+ ceramics showed upconversion luminescence peaking at 546 nm, 662 nm and 840 nm under the 980 nm excitation due to transition of 4 S 3/2 / 2 H 11/2 → 4 I 15/2 , 4 F 9/2 → 4 I 15/2 and 4 S 3/2 / 2 H 11/2 → 4 I 13/2 of Er 3+ ions, respectively. The infrared spectra exhibited strong emission at 1534 nm corresponds to 4 I 13/2 → 4 I 15/2 transition. The mechanism of the IR and visible emission bands in AlON:Er 3+ ceramics are discussed, which suggest it should be attractive for lighting and display devices applications.

  8. Influence of minor combined addition of Cr and Pr on microstructure, mechanical properties and corrosion behaviors of an ultrahigh strength Al-Zn-Mg-Cu-Zr alloy.

    Science.gov (United States)

    Wang, Ming; Huang, Lanping; Chen, Kanghua; Liu, Wensheng

    2018-01-01

    This work focuses on controlling grain boundary structure in an ultra-high strength Al-8.6Zn-2.5Mg-2.2Cu-0.16Zr (wt.%) alloy by the combined addition of trace Cr (0.1wt.%) and Pr (0.14wt.%), and evaluating mechanical properties and localized corrosion behaviors of the alloy in the peak aged condition. The introduction of trace Cr and Pr leads to the formation of nanoscale Cr, Pr-containing Al 3 Zr and Zr-containing PrCr 2 Al 20 dispersoids which can obviously inhibit the recrystallization and sub-grain growth of the super-high strength Al-Zn-Mg-Cu alloys, and retain the deformation-recovery microstructure dominated by low-angle grain boundaries. The nearly ellipsoidal dispersoids with a size of 10-35nm are discretely distributed and precipitate free zones are hardly formed in low-angle grain boundaries. This new alloy composition exhibits better combined properties, higher resistance to stress corrosion, exfoliation corrosion and inter-granular corrosion with the undamaged strength, ductility and fracture toughness. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Effects of Processing Parameters on Surface Roughness of Additive Manufactured Ti-6Al-4V via Electron Beam Melting

    Science.gov (United States)

    Sin, Wai Jack; Nai, Mui Ling Sharon; Wei, Jun

    2017-01-01

    As one of the powder bed fusion additive manufacturing technologies, electron beam melting (EBM) is gaining more and more attention due to its near-net-shape production capacity with low residual stress and good mechanical properties. These characteristics also allow EBM built parts to be used as produced without post-processing. However, the as-built rough surface introduces a detrimental influence on the mechanical properties of metallic alloys. Thereafter, understanding the effects of processing parameters on the part’s surface roughness, in turn, becomes critical. This paper has focused on varying the processing parameters of two types of contouring scanning strategies namely, multispot and non-multispot, in EBM. The results suggest that the beam current and speed function are the most significant processing parameters for non-multispot contouring scanning strategy. While for multispot contouring scanning strategy, the number of spots, spot time, and spot overlap have greater effects than focus offset and beam current. The improved surface roughness has been obtained in both contouring scanning strategies. Furthermore, non-multispot contouring scanning strategy gives a lower surface roughness value and poorer geometrical accuracy than the multispot counterpart under the optimized conditions. These findings could be used as a guideline for selecting the contouring type used for specific industrial parts that are built using EBM. PMID:28937638

  10. Synthesis and crystal structure of Na6[(UO2)3O(OH)3(SeO4)2]2·10H2O

    International Nuclear Information System (INIS)

    Baeva, E.Eh.; Serezhkina, L.B.; Virovets, A.V.; Peresypkina, E.V.

    2006-01-01

    The complex Na 6 [(UO 2 ) 3 O(OH) 3 (SeO 4 ) 2 ] 2 ·10H 2 O (I) is synthesized and studied by monocrystal X-ray diffraction. The compound crystallizes in the orthorhombic crystal system with the unit cell parameters: a=14.2225(7) A, b=18.3601(7) A, c=16.5406(6) A, V=4319.2(3) A 3, Z=4, space group Cmcm, R 1 =0.0406. Compound I is found to be a representative of the crystal-chemical group A 3 M 3 M 3 2 T 2 3 (A=UO 2 2+ , M 3 =O 2- , M 2 =OH - , T 3 =SeO 4 2- ) of the uranyl complexes; it contains layer uranium-containing groups [(UO 2 ) 3 O(OH) 3 (SeO 4 ) 2 ] 3- . These layers are linked to form a three-dimensional cage through bonds formed by the sodium atoms with the oxygen atoms of the uranyl ions and SeO 4 groups that belong to different layers [ru

  11. The influence of some additives to the highly carbohydrate diet on the distribution of Al, Ca, Mg, Mn and Na in teeth enamel and bones of experimental animals

    International Nuclear Information System (INIS)

    Bakyrdzhiev, P.

    1985-01-01

    An instrument neutron activation analysis had been used for the investigation of diets with different salt and permanent basic composition. The diets with MgCl 2 and methylene blue additives were used. Three groups of animals Wistar, Hamster and S. Dawley with different genetic reactivity had been fed on adlibidum for 45 days. After killing the animals the teeth enamel, mandibula and tibia had been sampled and content of Al, Mg, Mn, Na and Cl 2 was determined by means of INAA. The samples were irradiated for 1 min in the rabbit system of the experimental reactor IRT-2000. Two measurements were carried out - after a cooling time of 1 min for the determination of Al, Ca, Cl 2 , Mg, and after 2 h cooling time - for Na and Mn. The precision of the analysis was between 4 and 12%

  12. Wear- and heat resistance of vacuum-arc TiN and TiAlN based coatings with Si and Y additives

    International Nuclear Information System (INIS)

    Aksenov, I.I.; Belous, V.A.; Grigor'ev, A.N.; Ermolenko, I.G.; Zadneprovskij, Yu.A.; Kovalenko, V.I.; Lomino, N.S.; Marinin, V.G.; Tolmacheva, G.N.; Sobol', O.V.

    2011-01-01

    It is shown, that insertion of silicon additives into TiN coatings and of yttrium into TiAlN coatings in explored limits (to a few wht. %) leads to increasing of resistance against abrasive friction wear. At the same time silicon or yttrium presence in the coatings leads to loos of their columnar structure and demonstrate decrease in the cavitation resistance. It is supposed, that such distinction in behaviour of the given working performances is a consequence of that mechanisms of the coating surface fracture at action of cavitation and abrasive friction are different. All explored coatings of (Ti-Si)N composition are not oxidised up to 600 o C, and of (Ti-Al-Y)N coatings - up to 800 o C.

  13. Effects of Rhenium Addition on the Temporal Evolution of the Nanostructure and Chemistry of a Model Ni-Cr-Al Superalloy. 2; Analysis of the Coarsening Behavior

    Science.gov (United States)

    Yoon, Kevin E.; Noebe, Ronald D.; Seidman, David N.

    2007-01-01

    The temporal evolution of the nanostructure and chemistry of a model Ni-8.5 at.% Cr-10 at.% Al alloy with the addition of 2 at.% Re was studied using transmission electron microscopy and atom-probe tomography in order to measure the number density and mean radius of the y' (LIZ) precipitates and the chemistry of the y'-precipitates and the y (fcc)-matrix. In this article, the coarsening behavior of the y'-precipitates is discussed in detail and compared with the Umantsev-Olson model for multi-component alloys. In addition, the experimental results are evaluated with PrecipiCalc(TradeMark) simulations. The results show that the diffusivities of the solute elements play a major role in the coarsening behavior of the y'-precipitates and that the addition of Re retards the coarsening kinetics and stabilizes the spheroidal morphology of the precipitates by reducing the interfacial energy.

  14. Effect of additives in sintering UO2-7wt%Gd2O3 fuel pellets

    International Nuclear Information System (INIS)

    Santos, L.R.; Riella, H.G.

    2009-01-01

    Gadolinium has been used as burnable poison for reactivity control in modern PWRs. The incorporation of Gd 2 O 3 powder directly into the UO 2 powder enables longer fuel cycles and optimized fuel utilization. Nevertheless, processing by this method leads to difficulties while obtaining sintered pellets with the minimum required density. The process for manufacturing UO 2 - Gd 2 O 3 generates scraps that should be reused. The main scraps are green and sintered pellets, which must be calcined to U 3 O 8 to return to the fabrication process. Also, the incorporation of Gd 2 O 3 in UO 2 requires the use of an additive to improve the sintering process, in order to achieve the physical properties specified for the mixed fuel, mainly density and microstructure. This paper describes the effect of the addition of fabrication scraps on the properties of the UO 2 -Gd 2 O 3 fuel. Aluminum hydroxide Al(OH) 3 was also incorporated to the fuel as a sintering aid. The results shown that the use of 2000 ppm of Al(OH) 3 as additive allow to fabricate good pellets with up to 10 wt% of recycled scraps. (author)

  15. Corrosion behavior of Fe3Al intermetallics with addition of lithium, cerium and nickel in 2.5 % SO2+N2 at 900 °C

    Directory of Open Access Journals (Sweden)

    González-Rodríguez, J. G.

    2012-12-01

    Full Text Available The corrosion behavior of Fe3Al-type intermetallic alloys with addition of 1 at. % cerium, lithium and nickel at high temperature has been studied. The various alloys were exposed to an environment composed of 2.5 % SO2+N2 at 900 °C for 48 h. For all the intermetallic tested, the corrosion kinetics showed a parabolic behavior. The alloy, which showed less corrosion rate, was the Fe3AlNi alloy, being Fe3AlCeLi the alloy with the highest corrosion rate. For the various alloys, energy dispersive X-ray spectroscopy analysis, EDS, on the developed scale only detected aluminum, oxygen, and traces of iron and cerium, suggesting the formation of alumina as main component. The intermetallic alloys showed oxide cracking and spalling. The intermetallic chemical composition played an important role in defining the oxide scale morphology and the extent of damage.Se estudió el comportamiento a la corrosión a alta temperatura de intermetálicos tipo Fe3Al con adición de 1at. % de cerio, litio y níquel. Las diferentes aleaciones fueron expuestas bajo un ambiente compuesto de 2,5 % SO2+N2 a 900 °C durante 48 h. Para todos los intermetálicos ensayados, la cinética de corrosión presentó un comportamiento parabólico. La aleación que mostró la menor velocidad de corrosión fue el intermetálico Fe3AlNi, siendo el intermetálico Fe3AlCeLi el de mayor velocidad de corrosión. Los análisis mediante espectroscopía de dispersión de rayos X, EDS, sobre la costra formada identificaron únicamente aluminio, oxígeno y trazas de hierro y cerio, lo que sugiere la formación de alúmina como el componente principal. Los intermetálicos mostraron agrietamiento y desprendimiento de la costra de óxido. La composición química de los intermetálicos tuvo un papel importante en la definición de la morfología del óxido formado y el grado de daño.

  16. Sorptive stabilization of organic matter by amorphous Al hydroxide

    NARCIS (Netherlands)

    Schneider, M.P.W.; Scheel, T.; Mikutta, R.; van Hees, P.; Kaiser, K.; Kalbitz, K.

    2010-01-01

    Amorphous Al hydroxides (am-Al(OH)(3)) strongly sorb and by this means likely protect dissolved organic matter (OM) against microbial decay in soils. We carried out batch sorption experiments (pH 4.5; 40 mg organic C L-1) with OM extracted from organic horizons under a Norway spruce and a European

  17. Thermal stability of (AlSi)x(ZrVTi) intermetallic phases in the Al–Si–Cu–Mg cast alloy with additions of Ti, V, and Zr

    International Nuclear Information System (INIS)

    Shaha, S.K.; Czerwinski, F.; Kasprzak, W.; Friedman, J.; Chen, D.L.

    2014-01-01

    Highlights: • Al–Si–Cu–Mg alloy was modified by introducing Zr, V, and Ti. • The chemistry of the phases was identified using SEM/EDX. • The crystal lattice parameters of the phases were characterized using EBSD. • To investigate the phase stability, XRD was performed up to 600 °C. • Thermal analysis was done to find out the possible phase transformation reactions. - Abstract: The Al–Si–Cu–Mg cast alloy was modified with additions of Ti–V–Zr to improve the thermal stability of intermetallics at increased temperatures. A combination of electron microscopy, electron backscatter diffraction, and high temperature X-ray diffraction was explored to identify phases and temperatures of their thermal stability. The micro-additions of transition metals led to formation of several (AlSi) x (TiVZr) phases with D0 22 /D0 23 tetragonal crystal structure and different lattice parameters. While Cu and Mg rich phases along with the eutectic Si dissolved at temperatures from 300 to 500 °C, the (AlSi) x (TiVZr) phases were stable up to 696–705 °C which is the beneficial to enhance the high temperature properties. Findings of this study are useful for selecting temperatures during melting and heat treatment of Al–Si alloys with additions of transition metals

  18. The influence of SiO2 Addition on 2MgO-Al2O3-3.3P2O5 Glass

    DEFF Research Database (Denmark)

    Larsen, P.H.; Poulsen, F.W.; Berg, Rolf W.

    1999-01-01

    2MgO-Al2O3-3.3P2O5 glasses with increasing amounts of SiO2 are considered for sealing applications in Solid Oxide Fuel Cells (SOFC). The change in chemical durability under SOFC anode conditions and the linear thermal expansion is measured as functions of the SiO2 concentration. Raman spectroscopy...... analysis of the glasses reveals no sign of important changes in the glass structure upon SiO2 addition. Some increase in glass durability with SiO2 concentration is reported and its cause is discussed....

  19. Development of a high temperature high strength Al alloy by addition of small amounts of Sc and Mg to 2219 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Mondol, S. [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India); Alam, T.; Banerjee, R. [Advanced Materials and Manufacturing Processes Institute and Department of Materials Science and Engineering, University of North Texas, Denton, TX 76203-5017 (United States); Kumar, S. [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India); Chattopadhyay, K., E-mail: kamanio@materials.iisc.ernet.in [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India)

    2017-02-27

    The paper reports a significant improvement in tensile properties, in particular at 200 °C, of commercial 2219 Al alloy by addition of small amounts of Sc (0.8 wt%) and Mg (0.45 wt%), and employing copper mould suction casting followed by natural ageing and cold rolling. Microstructural examination and measurement of hardness were performed in order to explain the effects of Sc and Mg at each processing step. It is found that the remarkable improvement of room temperature strength occurs due to fine grain size, Al{sub 3}Sc and Al{sub 3}(Sc,Zr) dispersoids, GP zones on {100} and {111} planes, and work hardening. On exposure at 200 °C, the GP zones transform primarily to θ′ precipitates and a few Ω precipitates. Sc and Mg atoms segregate at the θ′/matrix interface, which suppress the coarsening of θ′ precipitates and make them stable at higher temperatures. Thus, the work reports extremely high 0.2% proof stress of 542 MPa at room temperature, 378 MPa at 200 °C and 495 MPa at room temperature after 200 h exposure at 200 °C accompanied by reasonable ductility. Theoretical yield strength is calculated on the basis of the observed microstructure and is found to be in good agreement with the experimentally obtained value.

  20. Development of a high temperature high strength Al alloy by addition of small amounts of Sc and Mg to 2219 alloy

    International Nuclear Information System (INIS)

    Mondol, S.; Alam, T.; Banerjee, R.; Kumar, S.; Chattopadhyay, K.

    2017-01-01

    The paper reports a significant improvement in tensile properties, in particular at 200 °C, of commercial 2219 Al alloy by addition of small amounts of Sc (0.8 wt%) and Mg (0.45 wt%), and employing copper mould suction casting followed by natural ageing and cold rolling. Microstructural examination and measurement of hardness were performed in order to explain the effects of Sc and Mg at each processing step. It is found that the remarkable improvement of room temperature strength occurs due to fine grain size, Al 3 Sc and Al 3 (Sc,Zr) dispersoids, GP zones on {100} and {111} planes, and work hardening. On exposure at 200 °C, the GP zones transform primarily to θ′ precipitates and a few Ω precipitates. Sc and Mg atoms segregate at the θ′/matrix interface, which suppress the coarsening of θ′ precipitates and make them stable at higher temperatures. Thus, the work reports extremely high 0.2% proof stress of 542 MPa at room temperature, 378 MPa at 200 °C and 495 MPa at room temperature after 200 h exposure at 200 °C accompanied by reasonable ductility. Theoretical yield strength is calculated on the basis of the observed microstructure and is found to be in good agreement with the experimentally obtained value.

  1. Ball-milling and AlB2 addition effects on the hydrogen sorption properties of the CaH2 + MgB2 system

    International Nuclear Information System (INIS)

    Schiavo, B.; Girella, A.; Agresti, F.; Capurso, G.; Milanese, C.

    2011-01-01

    Research highlights: → Calcium hydride + magnesium-aluminum borides as candidates for hydrogen storage. → Long time ball milling improves hydrogen sorption kinetics of the CaH 2 +MgB 2 system. → Coexistence of MgB 2 and AlB 2 does not improve hydrogen sorption performances. → Total substitution of MgB 2 with AlB 2 improves the system kinetics and reversibility. → Below 400 deg. C almost the full hydrogen capacity of the CaH 2 + AlB 2 system is reached. - Abstract: Among the borohydrides proposed for solid state hydrogen storage, Ca(BH 4 ) 2 is particularly interesting because of its favourable thermodynamics and relatively cheap price. Composite systems, where other species are present in addition to the borohydride, show some advantages in hydrogen sorption properties with respect to the borohydrides alone, despite a reduction of the theoretical storage capacity. We have investigated the milling time influence on the sorption properties of the CaH 2 + MgB 2 system from which Ca(BH 4 ) 2 and MgH 2 can be synthesized by hydrogen absorption process. Manometric and calorimetric measurements showed better kinetics for long time milled samples. We found that the total substitution of MgB 2 with AlB 2 in the starting material can improve the sorption properties significantly, while the co-existence of both magnesium and aluminum borides in the starting mixture did not cause any improvement. Rietveld refinements of the X-ray powder diffraction spectra were used to confirm the hypothesized reactions.

  2. Additive manufacturing of metals: a brief review of the characteristic microstructures and properties of steels, Ti-6Al-4V and high-entropy alloys

    Science.gov (United States)

    Gorsse, Stéphane; Hutchinson, Christopher; Gouné, Mohamed; Banerjee, Rajarshi

    2017-01-01

    Abstract We present a brief review of the microstructures and mechanical properties of selected metallic alloys processed by additive manufacturing (AM). Three different alloys, covering a large range of technology readiness levels, are selected to illustrate particular microstructural features developed by AM and clarify the engineering paradigm relating process–microstructure–property. With Ti-6Al-4V the emphasis is placed on the formation of metallurgical defects and microstructures induced by AM and their role on mechanical properties. The effects of the large in-built dislocation density, surface roughness and build atmosphere on mechanical and damage properties are discussed using steels. The impact of rapid solidification inherent to AM on phase selection is highlighted for high-entropy alloys. Using property maps, published mechanical properties of additive manufactured alloys are graphically summarized and compared to conventionally processed counterparts. PMID:28970868

  3. Black Carbon as an Additional Indicator of the Adverse Health Effects of Airborn Particles; Roet als additionele indicator voor de gezondheidseffecten van fijn stof

    Energy Technology Data Exchange (ETDEWEB)

    Janssen, N.; Fischer, P.; Cassee, F. [Rijksinstituut voor Volksgezondheid en Milieu RIVM, Bilthoven (Netherlands); Van Bree, L. [Planbureau voor de Leefomgeving PBL, Den Haag (Netherlands); Keuken, M. [TNO Gebouwde Omgeving, Utrecht (Netherlands); Hoek, G.; Brunekreef, B. [Institute for Risk Assessment Sciences IRAS, Universiteit Utrecht, Utrecht (Netherlands)

    2011-12-15

    The current standards for particulate matter are based on the mass concentration of particulates. In the study 'Black Carbon as an Additional Indicator of the Adverse Health Effects of Airborn Particles Compared to PM{sub 10} and PM{sub 2.5}' the authors investigated the value of carbon as an indicator of the public health effects of particulates in comparison with the mass concentration of particulates. [Dutch] De huidige normen voor fijn stof zijn gebaseerd op de massaconcentratie van fijnstofdeeltjes. In de studie 'Black Carbon as an Additional Indicator of the Adverse Health Effects of Airborn Particles Compared to PM{sub 10} and PM{sub 2.5}' onderzoeken de auteurs de toegevoegde waarde van roet als indicator voor de gezondheidseffecten van fijn stof in vergelijking met de massaconcentratie van fijn stof.

  4. Structure and electromagnetic properties of NiZn spinel ferrite with nano-sized ZnAl{sub 2}O{sub 4} additions

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Zongliang, E-mail: zzlma@163.com; Zhang, Huaiwu; Yang, Qinghui; Jia, Lijun

    2015-11-05

    In this study, nanocrystalline ZnAl{sub 2}O{sub 4} (ZA) (x = 0–20 wt%) were introduced into Ni{sub 0.4}Zn{sub 0.6}Fe{sub 2}O{sub 4} ferrite (NZ) by a solid-state reaction method combining a sol–gel auto-combustion method. The effects of ZA addition on the crystalline phase formation, microstructures, magnetic and dielectric properties were systematically investigated. X-ray diffraction and scanning electron microscope results reveal that the added ZA can fully solve into the NZ to form a ceramic with single-phase cubic spinel structure, and the grain size decreases obviously as x > 5 wt%. Meanwhile, the magnetic and dielectric properties exhibit significantly dependent on the ZA addition content. With the increasing addition level of ZA from 0 to 20 wt%, the initial permeability μ{sub i} is found increased initially and then decreased with the maximum 679 at x = 0.5 wt%. For the samples with x ≤ 5 wt%, permittivity ε′ is relatively higher at low frequencies (ε′ = 91–138 at 1 MHz) and dielectric loss tan δ{sub ε} shows distinct peak behavior. When x reaches 10 wt%, however, the ε′ and tan δ{sub ε} show very stable spectra from 1 MHz to 1 GHz. - Highlights: • Various amount of nanocrystalline ZnAl{sub 2}O{sub 4} (ZA) were introduced into NiZn ferrite. • NiZn ferrite can form single-phase spinel ceramic materials with ZA additives. • ZA has significant effects on magnetic and dielectric properties of the ceramics. • It provides a new method for fabricating NiZn ferrite with tunable properties.

  5. Improvement of the thermoplastic formability of Zr65Cu17.5Ni10Al7.5 bulk metallic glass by minor addition of Erbium

    International Nuclear Information System (INIS)

    Hu, Q.; Zeng, X.R.; Fu, M.W.; Chen, S.S.; Jiang, J.

    2016-01-01

    The softness of Zr 65 Cu 17.5 Ni 10 Al 7.5 bulk metallic glass (BMG) in the super-cooled liquid range (SCLR) is obviously improved by minor addition of 2% Er, which makes (Zr 65 Cu 17.5 Ni 10 Al 7.5 ) 98 Er 2 (Zr65Er2) to be a very formable Be-free Zr-based BMG. It is found the lower glass transition temperature of Zr65Er2 has an important contribution to the improvement of formability, which is contrary to the general understanding that the larger fragility and wider super-cooled liquid region (SCLR) are the major reasons for better thermoplastic formability. This finding is well explained by using the linear simplification of the SCLR in Angell plot. Zr65Er2 also has lower crystallization temperature and melting temperature, which is believed to be related to the formation of short-range ordering with lower transition energy rather than the composition shift to near eutectic. The above results help understand the effect of minor addition of rare-earth to the formability of Zr-based bulk metallic glasses.

  6. Effect of MgCl2 addition on the sintering behavior of MgAl2O4 spinel and formation of nano-particles

    Directory of Open Access Journals (Sweden)

    Mohammadi F.

    2014-01-01

    Full Text Available In this paper, the effect of MgCl2 addition on the sintering behavior of MgAl2O4 spinel produced via oxide mixture method was investigated. For this reason, the stoichiometric mixture of magnesite and calcined alumina as raw materials was calcined at 1100°C. The calcined mixture was milled, pressed and then, fired at 1300 and 1500°C after addition of various amounts of MgCl2. Besides, the physical properties, phase composition and microstructure of fired samples were investigated. The results showed that MgCl2 addition has great effect on the densification and particle size of spinel. Besides, MgCl2 addition increases the amount of spinel phase at all firing temperatures. Due to the decomposition of MgCl2 and then formation of ultra-fine MgO particles, the nano-sized spinel is formed on the surface of the larger spinel particles.

  7. Application of the Akinfiev-Diamond equation of state to neutral hydroxides of metalloids (B(OH)3, Si(OH)4, As(OH)3) at infinite dilution in water over a wide range of the state parameters, including steam conditions

    Science.gov (United States)

    Akinfiev, Nikolay N.; Plyasunov, Andrey V.

    2014-02-01

    The Akinfiev and Diamond (2003) equation of state (EoS) for aqueous nonelectrolytes was employed to describe hydroxides of metalloids (B(OH)3, Si(OH)4, As(OH)3) over a wide temperature and pressure ranges, including steam conditions. The EoS is based on the accurate knowledge of solvent (H2O) properties and requires only three empirical parameters to be fitted to experimental data, and these are independent of temperature and pressure. For nonvolatile components thermodynamic properties of species in the ideal gas state were evaluated using quantum chemical computations. The proposed approach has been tested to predict the whole set of thermodynamic properties of solutes (the chemical potential, entropy, molar volume, and molar heat capacity) over a wide range of temperatures (273-1200 K) and pressures (0.1-1000 MPa), including the near-critical region and both low and high density regions of the solvent. Thus it can be used for modeling various geochemical processes over a whole range of solvent densities, including processes in boiling fluids and a vapor phase as well. solubility data in a low density aqueous fluid (ρ1∗ 1 mol kg-1) where polymerization effects may take place (Newton and Manning, 2003); the rest of data, containing the majority of quartz solubility points at 293-1273 K, 0.1-1000 MPa. Only the 3rd part of experimental quartz solubility data has been used in the fitting procedure. Thermodynamic properties of Si(OH)4 in the ideal gas state were recently determined by the analysis of the relevant experimental data in Plyasunov (2011b). The temperature dependence of heat capacity of the molecule was adopted from comprehensive study of Rutz and Bockhorn (2005)where DFT calculations at different levels of theory including CBS-QBS and G3MP2 methods, as well as corrections for hindered rotations and scaling for vibration frequencies were employed. The adopted Cpo (T = 300-1500 K) values for gaseous Si(OH)4 were approximated by a function and used in the

  8. A Comparative Study of Additively Manufactured Thin Wall and Block Structure with Al-6.3%Cu Alloy Using Cold Metal Transfer Process

    Directory of Open Access Journals (Sweden)

    Baoqiang Cong

    2017-03-01

    Full Text Available In order to build a better understanding of the relationship between depositing mode and porosity, microstructure, and properties in wire + arc additive manufacturing (WAAM 2319-Al components, several Al-6.3%Cu deposits were produced by WAAM technique with cold metal transfer (CMT variants, pulsed CMT (CMT-P and advanced CMT (CMT-ADV. Thin walls and blocks were selected as the depositing paths to make WAAM samples. Porosity, microstructure and micro hardness of these WAAM samples were investigated. Compared with CMT-P and thin wall mode, CMT-ADV and block process can effectively reduce the pores in WAAM aluminum alloy. The microstructure varied with different depositing paths and CMT variants. The micro hardness value of thin wall samples was around 75 HV from the bottom to the middle, and gradually decreased toward the top. Meanwhile, the micro hardness value ranged around 72–77 HV, and varied periodically in block samples. The variation in micro hardness is consistent with standard microstructure characteristics.

  9. Effect of Tool-Path on Morphology and Mechanical Properties of Ti-6Al-4V Fabricated by Wire and Arc Additive Manufacturing

    Directory of Open Access Journals (Sweden)

    Fu Jie

    2017-01-01

    Full Text Available Ti-6Al-4V components are widely used in aerospace industry. However, it’s not economic to manufacture them in traditional subtractive methods. Wire and arc additive manufacturing (WAAM is a promising alternative technology for fabricating it efficiently and economically. Tool-path planning strategy is a very important step in WAAM process. This paper investigated the influence of the lap way between layers and layers in tool-path on the Ti-6Al-4V samples fabricated by WAAM. It has been found that the lap way between layers and layers in tool-path do influence the forming quality and especially mechanical properties of the fabricated samples. Samples have different surface quality (smooth or undulating and defects inside or on the surface of the components. The highest and smallest ultra tensile strength of the fabricated samples are respectively 907.86 MPa, 684.82 MPa. But it has few effect on the grains of the fabricated samples, and they all have cross-sectional columnar grains.

  10. The Influence of As-Built Surface Conditions on Mechanical Properties of Ti-6Al-4V Additively Manufactured by Selective Electron Beam Melting

    Science.gov (United States)

    Sun, Y. Y.; Gulizia, S.; Oh, C. H.; Fraser, D.; Leary, M.; Yang, Y. F.; Qian, M.

    2016-03-01

    Achieving a high surface finish is a major challenge for most current metal additive manufacturing processes. We report the first quantitative study of the influence of as-built surface conditions on the tensile properties of Ti-6Al-4V produced by selective electron beam melting (SEBM) in order to better understand the SEBM process. Tensile ductility was doubled along with noticeable improvements in tensile strengths after surface modification of the SEBM-fabricated Ti-6Al-4V by chemical etching. The fracture surfaces of tensile specimens with different surface conditions were characterised and correlated with the tensile properties obtained. The removal of a 650- μm-thick surface layer by chemical etching was shown to be necessary to eliminate the detrimental influence of surface defects on mechanical properties. The experimental results and analyses underline the necessity to modify the surfaces of SEBM-fabricated components for structural applications, particularly for those components which contain complex internal concave and convex surfaces and channels.

  11. Fatigue Performance of Ti-6Al-4V Additively Manufactured Specimens with Integrated Capillaries of an Embedded Structural Health Monitoring System.

    Science.gov (United States)

    Hinderdael, Michaël; Strantza, Maria; De Baere, Dieter; Devesse, Wim; De Graeve, Iris; Terryn, Herman; Guillaume, Patrick

    2017-08-25

    Additive manufacturing (AM) of metals offers new possibilities for the production of complex structures. Up to now, investigations on the mechanical response of AM metallic parts show a significant spread and unexpected failures cannot be excluded. In this work, we focus on the detection of fatigue cracks through the integration of a Structural Health Monitoring (SHM) system in Ti-6Al-4V specimens. The working principle of the presented system is based on the integration of small capillaries that are capable of detecting fatigue cracks. Four-point bending fatigue tests have been performed on Ti-6Al-4V specimens with integrated capillaries and compared to the reference specimenswithout capillaries. Specimens were produced by conventional subtractive manufacturing of wrought material and AM, using the laser based Directed Energy Deposition (DED) process. In this study, we investigated the effect of the presence of the capillary on the fatigue strength and fatigue initiation location. Finite element (FEM) simulations were performed to validate the experimental test results. The presence of a drilled capillary in the specimens did not alter the fatigue initiation location. However, the laser based DED production process introduced roughness on the capillary surface that altered the fatigue initiation location to the capillary surface. The fatigue performance was greatly reduced when considering a printed capillary. It is concluded that the surface quality of the integrated capillary is of primary importance in order not to influence the structural integrity of the component to be monitored.

  12. Morphology and performances of the anodic oxide films on Ti6Al4V alloy formed in alkaline-silicate electrolyte with aminopropyl silane addition under low potential

    International Nuclear Information System (INIS)

    Chen, Jiali; Wang, Jinwei; Yuan, Hongye

    2013-01-01

    Oxide films on Ti6Al4V alloy are prepared using sodium hydroxide–sodium silicate as the base electrolyte with addition of aminopropyl trimethoxysilane (APS) as additive by potentiostatic anodizing under 10 V. APS is incorporated into the films during anodizing and the surface morphology of the oxide films is changed from particle stacked to honeycomb-like porous surfaces as shown by scanning electron microscopy (SEM) with Energy Disperse Spectroscopy (EDX). The surface roughness and aminopropyl existence on the oxide films result in their differences in wettability as tested by the surface profile topography and contact angle measurements. The anti-abrasive ability of the anodic films is improved with the addition of APS due to its toughening effects and serving as lubricants in the ceramic oxide films as measured by ball-on-disk friction test. Also, potentiodynamic corrosion test proves that their anticorrosive ability in 3.5 wt.% NaCl is greatly improved as reflected by their much lower corrosion current (I corr ) and higher corrosion potential (E corr ) than those of the substrate.

  13. Morphology and performances of the anodic oxide films on Ti6Al4V alloy formed in alkaline-silicate electrolyte with aminopropyl silane addition under low potential

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jiali; Wang, Jinwei, E-mail: wangjw@ustb.edu.cn; Yuan, Hongye

    2013-11-01

    Oxide films on Ti6Al4V alloy are prepared using sodium hydroxide–sodium silicate as the base electrolyte with addition of aminopropyl trimethoxysilane (APS) as additive by potentiostatic anodizing under 10 V. APS is incorporated into the films during anodizing and the surface morphology of the oxide films is changed from particle stacked to honeycomb-like porous surfaces as shown by scanning electron microscopy (SEM) with Energy Disperse Spectroscopy (EDX). The surface roughness and aminopropyl existence on the oxide films result in their differences in wettability as tested by the surface profile topography and contact angle measurements. The anti-abrasive ability of the anodic films is improved with the addition of APS due to its toughening effects and serving as lubricants in the ceramic oxide films as measured by ball-on-disk friction test. Also, potentiodynamic corrosion test proves that their anticorrosive ability in 3.5 wt.% NaCl is greatly improved as reflected by their much lower corrosion current (I{sub corr}) and higher corrosion potential (E{sub corr}) than those of the substrate.

  14. Effects of Cu and Ag additions on age-hardening behavior during multi-step aging in Al--Mg--Si alloys

    International Nuclear Information System (INIS)

    Kim, JaeHwang; Daniel Marioara, Calin; Holmestad, Randi; Kobayashi, Equo; Sato, Tatsuo

    2013-01-01

    Low Cu and Ag additions (≤0.10 at%) were found to strongly affect the age-hardening behavior in Al--Mg--Si alloys with Mg+Si>1.5 at%. The hardness increased during aging at 170 °C and the formation of β ″ precipitates was kinetically accelerated. The activation energy of the formation of the β ″ phase was calculated to 127, 105, 108 and 99 KJmol −1 in the base, Cu-added, Ag-added and Cu--Ag-added alloys, respectively using the Kissinger method. The negative effect of two-step aging caused by the formation of Cluster (1) during natural aging was not overcome by the addition of microalloying elements. However, it was suppressed by the formation of Cluster (2) through a pre-aging at 100 °C. Quantitative analysis of the precipitate microstructure was performed using a transmission electron microscope equipped with a parallel electron energy loss spectrometer for the determination of specimen thickness. The formation of Cluster (2) was found to increase the number density of β ″ precipitates, whereas the formation of Cluster (1) decreased the number density and increased the needle length. The effects of low Cu and Ag additions in combination with multi-step aging are discussed based on microstructure observations and hardness and resistivity measurements.

  15. Effect of Ag additions on the lengthening rate of Ω plates and formation of σ phase in Al-Cu-Mg alloys during thermal exposure

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yaru; Liu, Zhiyi, E-mail: liuzhiyi@csu.edu.cn; Bai, Song; Ying, Puyou; Lin, Lianghua

    2017-01-15

    Effect of Ag additions on the mechanical properties and microstructures of the peak-aged Al-Cu-Mg alloys during prolonged thermal exposure at 150 °C, was investigated by tensile testing, conventional transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). The results showed that after exposure for 500 h, > 85% of the peak strength remained. Microstructure observations indicated that increasing the Ag content from 0.14 to 0.57% promoted the precipitation of a fine and uniform Ω phase and suppressed the formation of the θ′ phase, leading to a notable improvement of the strength properties and thermal stability of the studied alloys. Quantitative TEM analysis showed that the coarsening of Ω phase was predominated by plate lengthening rather than thickening, while its lengthening rate was independent of various Ag additions during exposure at 150 °C. In addition, an increase of Ag also facilitated the formation of a cubic σ phase, which was further supported by STEM results. - Highlights: •Increasing Ag improved strength properties and thermal stability of the alloys. •After exposure for 500 h, > 85% of the peak strength remained. •The lengthening rate of Ω plates remained constant as Ag increased at 150 °C. •Increasing Ag content facilitated the formation of σ phase.

  16. Effect of Molten Pool Size on Microstructure and Tensile Properties of Wire Arc Additive Manufacturing of Ti-6Al-4V Alloy.

    Science.gov (United States)

    Wu, Qianru; Lu, Jiping; Liu, Changmeng; Fan, Hongli; Shi, Xuezhi; Fu, Jie; Ma, Shuyuan

    2017-07-04

    Wire arc additive manufacturing (WAAM) technique is a cost-competitive and efficient technology to produce large structure components in industry domains. Mechanical properties are mainly dominated by the microstructure of the components, which is deeply affected by the molten pool size. In this work, to investigate the effect of the molten pool size on microstructure and mechanical properties of the components, a series of Ti-6Al-4V alloy blocks with different width of molten pool (WMP) ranging from 7 mm to 22 mm were deposited by adjusting the wire feed speed (WFS) from 100 cm/min to 500 cm/min. It is interesting to find that the macrostructure changes from columnar grains to equiaxial grains, and then returns to large columnar grains with the increase of WMP, which is mainly caused by the different cooling rates and thermal gradients. Nonetheless, the tensile properties of the components have a tendency to decline with the increase of WMP.

  17. Effects of Rhenium Addition on the Temporal Evolution of the Nanostructure and Chemistry of a Model Ni-Cr-Al Superalloy. 1; Experimental Observations

    Science.gov (United States)

    Yoon, Kevin E.; Noebe, Ronald D.; Seidman, David N.

    2006-01-01

    The temporal evolution of the nanostructure and chemistry of a model Ni-8.5 at.% Cr-10 at. % Al alloy, with the addition of 2 at.% Re, aged at 1073 K from 0.25 to 264 h, was studied. Transmission electron microscopy and atom-probe tomography were used to measure the number density and mean radius of the gamma prime (L1(sub 2) structure)-precipitates and the chemistry of the gamma prime-precipitates and the gamma (face-centered cubic)-matrix, including the partitioning behavior of all alloying elements between the gamma- and gamma prime-phases and the segregation behavior at gamma/gamma prime interfaces. The precipitates remained spheroidal for an aging time of up to 264 h and, unlike commercial nickel-based superalloys containing Re, there was not confined (nonmonotonic) Re segregation at the gamma/gamma prime interfaces.

  18. Wire-based laser metal deposition for additive manufacturing of TiAl6V4: basic investigations of microstructure and mechanical properties from build up parts

    Science.gov (United States)

    Klocke, Fritz; Arntz, Kristian; Klingbeil, Nils; Schulz, Martin

    2017-02-01

    The wire-based laser metal deposition (LMD-W) is a new technology which enables to produce complex parts made of titanium for the aerospace and automotive industry. For establishing the LMD-W as a new production process it has to be proven that the properties are comparable or superior to conventional produced parts. The mechanical properties were investigated by analysis of microstructure and tensile test. Therefore, specimens were generated using a 4.5 kW diode laser cladding system integrated in a 5-Axis-machining center. The structural mechanical properties are mainly influence by crystal structure and thereby the thermal history of the work piece. Especially the high affinity to oxide, distortion and dual phase microstructure make titanium grade 5 (TiAl6V4) one of the most challenging material for additive manufacturing. By using a proper local multi-nozzle shielding gas concept the negative influence of oxide in the process could be eliminated. The distortion being marginal at a single bead, accumulated to a macroscopic effect on the work piece. The third critical point for additive processing of titanium, the bimodal microstructure, could not be cleared by the laser process alone. All metallurgical probes showed α-martensitic-structure. Therefore, a thermal treatment became a necessary production step in the additive production chain. After the thermal treatment the microstructure as well as the distortion was analyzed and compared with the status before. Although not all technical issues could be solved, the investigation show that LMD-W of titanium grade 5 is a promising alternative to other additive techniques as electronic beam melting or plasma deposition welding.

  19. A comparison of porosity analysis using 2D stereology estimates and 3D serial sectioning for additively manufactured Ti 6Al 2Sn 4Zr 2Mo alloy

    International Nuclear Information System (INIS)

    Ganti, Satya R.; Velez, Michael A.; Geier, Brian A.; Hayes, Brian J.; Turner, Bryan J.; Jenkins, Elizabeth J.

    2017-01-01

    Porosity is a typical defect in additively manufactured (AM) parts. Such defects limit the properties and performance of AM parts, and therefore need to be characterized accurately. Current methods for characterization of defects and microstructure rely on classical stereological methods that extrapolate information from two dimensional images. The automation of serial sectioning provides an opportunity to precisely and accurately quantify porosity in three dimensions in materials. In this work, we analyzed the porosity of an additively manufactured Ti 6Al 2Sn 4Zr 2Mo sample using Robo-Met.3D "r"e"g"i"s"t"e"r"e"d, an automated serial sectioning system. Image processing for three dimensional reconstruction of the serial-sectioned two dimensional images was performed using open source image analysis software (Fiji/ImageJ, Dream.3D, Paraview). The results from this 3D serial sectioning analysis were then compared to classical 2D stereological methods (Saltykov stereological theory). We found that for this dataset, the classical 2D methods underestimated the porosity size and distributions of the larger pores; a critical attribute to fatigue behavior of the AM part. The results suggest that acquiring experimental data with equipment such as Robo-Met.3D "r"e"g"i"s"t"e"r"e"d to measure the number and size of particles such as pores in a volume irrespective of knowing their shape is a better choice.

  20. The influence of small SO2 additions on the corrosion behaviour of NiCrAl alloys at 1000-1100deg C

    International Nuclear Information System (INIS)

    Wasserfuhr, C.H.; Quadakkers, W.J.; Schuster, H.; Nickel, H.

    1990-06-01

    The corrosion behaviour of NiCrAl alloys in air containing small amounts of SO 2 has been investigated. The alloys containing 9-20 wt.% chromium and 6-10 wt% aluminium were oxidized in air and in air containing 1 vol% SO 2 . In addition to long term tests, the initial stages of oxidation were examined using various surface analysis techniques. The results have shown that small SO 2 additions to the test atmosphere cause a much higher oxidation rate, especially for cast alloys of low chromium and high aluminium contents. The mechanism of the deleterious effect of SO 2 on the oxidation rate was studied in two ways: measurement of the gas-metal reaction kinetics using gas chromatographical analysis of the test gas, investigation of trace amounts of sulphur in the alloy. On the basis of the results obtained, it can be shown that the high oxidation rates caused by the presence of SO 2 in the test atmosphere can be significantly reduced by increasing the chromium content of the alloy, by adding yttrium to the alloy, and by ensuring a fine-grained microstructure. (orig.) [de

  1. The effect of Nb addition on mechanical properties, corrosion behavior, and metal-ion release of ZrAlCuNi bulk metallic glasses in artificial body fluid.

    Science.gov (United States)

    Qiu, C L; Liu, L; Sun, M; Zhang, S M

    2005-12-15

    Bulk metallic glasses (BMGs) of Zr(65 - x)Nb(x)- Cu(17.5)Ni(10)Al(7.5) with Nb = 0, 2, and 5 at % were prepared by copper mold casting. Compression tests reveal that the two BMGs containing Nb exhibited superior strength and plasticity to the base alloy. The corrosion behavior of the alloys obtained was investigated in artificial body fluid by electrochemical measurements. It was found that the addition of Nb significantly enhanced the corrosion resistance of the Zr-based BMG, as indicated by a remarkable increase in corrosion potential and pitting potential. XPS analysis revealed that the passive film formed after anodic polarization was enriched in aluminum oxide and depleted in phosphate ions for the BMGs containing Nb, which accounts for the improvement of corrosion resistance. On the other hand, metal-ion release of different BMGs were determined in PPb (ng/mL) level with inductively coupled plasma mass spectrometry (ICP-MS) after being immersed in artificial body fluid at 37 degrees C for 20 days. It was found that the addition of Nb considerably reduced the ion release of all kinds of metals of the base system. This is probably attributed to the promoting effect of Nb on a rapid formation of highly protective film.

  2. The natural aging and precipitation hardening behaviour of Al-Mg-Si-Cu alloys with different Mg/Si ratios and Cu additions

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Lipeng [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 China (China); Jia, Zhihong, E-mail: zhihongjia@cqu.edu.cn [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 China (China); Zhang, Zhiqing; Sanders, Robert E.; Liu, Qing [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 China (China); Yang, Guang [Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education and International Centre for Dielectric Research, Xi’an Jiaotong University, Xi’an 710049 (China)

    2015-03-11

    The natural aging and artificial aging behaviours of Al-Mg-Si-Cu alloys with different Mg/Si ratios and Cu additions were investigated using Vickers microhardness measurements, differential scanning calorimetry (DSC) analysis and transmission electron microscopy (TEM) characterisation. Excess Si and Cu additions enhanced the alloy hardening ability during natural (NA) and artificial aging (AA). Alloys with low Cu and high Si contents exhibited higher precipitation hardening than alloys rich in Mg during artificial aging. In contrast, the alloys with high amounts of Cu were less dependent on the Mg/Si ratio during precipitation hardening due to their similar aging kinetics. The main precipitate phases that contributed to the peak-aging hardness were the L, Q′ and β″ phases. In the over-aging conditions, the alloys rich in Mg and Cu had finer and more numerous precipitates than their Si-rich equivalents due to the preferential precipitation of the L phase. The combination of excess Mg and high Cu resulted in an alloy with a relatively low hardness in T4 temper and a relatively higher hardness after the paint baking cycle. Thus, this alloy has good potential for use in auto body panel applications.

  3. Influence of Inherent Surface and Internal Defects on Mechanical Properties of Additively Manufactured Ti6Al4V Alloy: Comparison between Selective Laser Melting and Electron Beam Melting.

    Science.gov (United States)

    Fousová, Michaela; Vojtěch, Dalibor; Doubrava, Karel; Daniel, Matěj; Lin, Chiu-Feng

    2018-03-31

    Additive manufacture (AM) appears to be the most suitable technology to produce sophisticated, high quality, lightweight parts from Ti6Al4V alloy. However, the fatigue life of AM parts is of concern. In our study, we focused on a comparison of two techniques of additive manufacture-selective laser melting (SLM) and electron beam melting (EBM)-in terms of the mechanical properties during both static and dynamic loading. All of the samples were untreated to focus on the influence of surface condition inherent to SLM and EBM. The EBM samples were studied in the as-built state, while SLM was followed by heat treatment. The resulting similarity of microstructures led to comparable mechanical properties in tension, but, due to differences in surface roughness and specific internal defects, the fatigue strength of the EBM samples reached only half the value of the SLM samples. Higher surface roughness that is inherent to EBM contributed to multiple initiations of fatigue cracks, while only one crack initiated on the SLM surface. Also, facets that were formed by an intergranular cleavage fracture were observed in the EBM samples.

  4. Influence of Inherent Surface and Internal Defects on Mechanical Properties of Additively Manufactured Ti6Al4V Alloy: Comparison between Selective Laser Melting and Electron Beam Melting

    Directory of Open Access Journals (Sweden)

    Michaela Fousová

    2018-03-01

    Full Text Available Additive manufacture (AM appears to be the most suitable technology to produce sophisticated, high quality, lightweight parts from Ti6Al4V alloy. However, the fatigue life of AM parts is of concern. In our study, we focused on a comparison of two techniques of additive manufacture—selective laser melting (SLM and electron beam melting (EBM—in terms of the mechanical properties during both static and dynamic loading. All of the samples were untreated to focus on the influence of surface condition inherent to SLM and EBM. The EBM samples were studied in the as-built state, while SLM was followed by heat treatment. The resulting similarity of microstructures led to comparable mechanical properties in tension, but, due to differences in surface roughness and specific internal defects, the fatigue strength of the EBM samples reached only half the value of the SLM samples. Higher surface roughness that is inherent to EBM contributed to multiple initiations of fatigue cracks, while only one crack initiated on the SLM surface. Also, facets that were formed by an intergranular cleavage fracture were observed in the EBM samples.

  5. Influence of the addition of chromium in the microstructure and property of Cu-Al-Ni shape memory alloy; Influencia do cromo na microestrutura e propriedade de ligas Cu-Al-Ni com efeito memoria de forma

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, C.A.; Coelho, R.E.; Lima, P.C. de; Carvalho, C.O. de; Conrado, L.C., E-mail: amilateixeira93@hotmail.com [Instituto Federal de Educacao, Ciencia e Tecnologia da Bahia (IFBA), BA (Brazil)

    2016-07-01

    The Copper based alloys with addition of a fourth element have been studied for 20 years. These alloys, depending on their composition present shape memory effect structure and now a day possess a diversity of applications. Considering the importance of these materials, it was developed in this research alloys of Cu-Al-Ni with addition of Cr in different percentages (0.2, 0.4, 0.7 and 2.26wt.%). A plasma furnace (Company-EDG, model-Discovery), with vacuum control and argon gas injection, was utilized. Posteriorly, the samples underwent heat treatment of solubilization. This treatment consisted in submitting all samples to a temperature of 900 deg C for 1 hour and followed by water solution (salt, water, ice and alcohol) quenching at a temperature of -10 deg C. The samples were polished and etched with Ferric Chloride. All samples were analyzed X-ray Fluorescence, Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). XRD was carried out with a tension 30kV from 25 deg to 100 deg. It was possible to verify, through the obtained SEM images, that Cr has a fundamental role in the martensite structure evolution and with XRD analyses it was observed that with the increase of Cr, results in the formation of phases 18R and 2H with a decrease of phase γ2, the last one unwanted to this type of alloy. (author)

  6. Effect of cooling rate and Mg addition on the structural evaluation of rapidly solidified Al-20wt%Cu-12wt%Fe alloy

    Energy Technology Data Exchange (ETDEWEB)

    Karaköse, Ercan, E-mail: ekarakose@karatekin.edu.tr [Çankırı Karatekin University, Faculty of Sciences, Department of Physics, 18100 Çankırı (Turkey); Çolak, Hakan [Çankırı Karatekin University, Faculty of Sciences, Department of Chemistry, 18100 Çankırı (Turkey)

    2016-11-15

    The present work examines the effect of Mg contents and cooling rate on the morphology and mechanical properties of Al{sub 20}Cu{sub 12}Fe quasicrystalline alloy. The microstructure of the alloys was analyzed by scanning electron microscopy and the phase composition was identified by X-ray diffractometry. The melting characteristics were studied by differential thermal analysis under an Ar atmosphere. The mechanical features of the melt-spun and conventionally solidified alloys were tested by tensile-strength test and Vickers micro-hardness test. It was found that the final microstructure of the Al{sub 20}Cu{sub 12}Fe samples mainly depends on the cooling rate and Mg contents, which suggests that different cooling rates and Mg contents produce different microstructures and properties. The average grain sizes of the melt spun samples were about 100–300 nm at 35 m/s. The nanosize, dispersed, different shaped quasicrystal particles possessed a remarkable effect to the mechanical characteristics of the rapidly solidified ribbons. The microhardness values of the melt spun samples were approximately 18% higher than those of the conventionally counterparts. - Highlights: •Quasicrystal-creating materials have high potential for applications. •Different shaped nanosize quasicrystal particles were observed. •The addition of Mg has an important impact on the mechanical properties. •H{sub V} values of the MS0, MS3 and MS5 samples at 35 m/s were 8.56, 8.66 and 8.80 GPa. •The volume fraction of IQC increases with increasing cooling rates.

  7. Batagayite, CaZn2(Zn,Cu)6(PO4)4(PO3OH)3·12H2O, a new phosphate mineral from Këster tin deposit (Yakutia, Russia): occurrence and crystal structure

    Science.gov (United States)

    Yakovenchuk, Victor N.; Pakhomovsky, Yakov A.; Konopleva, Nataliya G.; Panikorovskii, Taras L.; Bazai, Ayya; Mikhailova, Julia A.; Bocharov, Vladimir N.; Ivanyuk, Gregory Yu.; Krivovichev, Sergey V.

    2017-12-01

    Batagayite, CaZn2(Zn,Cu)6(PO4)4(PO3OH)3·12H2O, is a new secondary phosphate mineral from the Këster deposit, Arga-Ynnykh-Khai massif, NE Yakutia, Russia. It is monoclinic, P21, a = 8.4264(4), b = 12.8309(6), c = 14.6928(9) Å, β = 98.514(6)o, V = 1571.05(15) Å3 and Z = 2 (from single-crystal X-ray diffraction data). Batagayite crystals are blades up to 2 mm long, flattened on {001} and elongated on [100]; blades often grow in radial aggregates. Associated minerals are arsenolite, native copper, epifanovite, fluorapatite, libethenite, Na-analogue of batagayite, pseudomalachite, quartz, sampleite, tobermorite, and Mg-analogue of hopeite. The streak is white and the luster is vitreous. The mineral is brittle and has a perfect cleavage on {001}, no parting was observed. The Mohs hardness is 3. Density, determined by the float-sink method in Clerici solution, is 2.90(3) g/cm3, and the calculated density is 3.02 g/cm3 (using the empirical formula and single-crystal unit-cell parameters). Batagayite is biaxial, optically negative, α = 1.566 ± 0.002, β = 1.572 ± 0.002, γ = 1.573 ± 0.002 at 589 nm. 2V meas. = 40(5)°, 2V calc = 44.3°. Optical orientation: Z is perpendicular to (001), further details unclear. No dispersion or pleochroism were observed. The mean chemical composition determined by electron microprobe is: Na2O 0.31, MgO 1.39, Al2O3 0.55, SiO2 0.48, P2O5 34.37, K2O 0.17, CaO 2.76, MnO 1.03, CuO 5.80, ZnO 35.62, CdO 0.24 wt%. The H2O content estimated from the crystal-structure refinement is 16.83 wt%, giving a total of 99.55 wt%. The empirical formula calculated on the basis of P + Si = 7 is (Zn6.22Cu1.04Ca0.70Mg0.49Mn0.21Al0.15Na0.14K0.05Cd0.03)Σ9.03(P6.89Si0.11)Σ7.00O24.91(OH)3.09·12.10H2O. The mineral easily dissolves in 10% room-temperature HCl. The eight diagnostic lines in the X-ray powder-diffraction pattern are (I-d[Å]-hkl): 100-14.59-001, 25-6.34-012, 11-6.02-111, 37-4.864-003, 13-4.766-112, 20-3.102-1 \\overline {2} \\overline {4} , 11

  8. Effect of Molten Pool Size on Microstructure and Tensile Properties of Wire Arc Additive Manufacturing of Ti-6Al-4V Alloy

    Directory of Open Access Journals (Sweden)

    Qianru Wu

    2017-07-01

    Full Text Available Wire arc additive manufacturing (WAAM technique is a cost-competitive and efficient technology to produce large structure components in industry domains. Mechanical properties are mainly dominated by the microstructure of the components, which is deeply affected by the molten pool size. In this work, to investigate the effect of the molten pool size on microstructure and mechanical properties of the components, a series of Ti-6Al-4V alloy blocks with different width of molten pool (WMP ranging from 7 mm to 22 mm were deposited by adjusting the wire feed speed (WFS from 100 cm/min to 500 cm/min. It is interesting to find that the macrostructure changes from columnar grains to equiaxial grains, and then returns to large columnar grains with the increase of WMP, which is mainly caused by the different cooling rates and thermal gradients. Nonetheless, the tensile properties of the components have a tendency to decline with the increase of WMP.

  9. Spark plasma sintering of α-Si3N4 ceramics with Al2O3 and Y2O3 as additives and its morphology transformation

    International Nuclear Information System (INIS)

    Ceja-Cardenas, L.; Lemus-Ruiz, J.; Jaramillo-Vigueras, D.; Torre, S.D. de la

    2010-01-01

    The spark plasma sintering SPS technique has been used to densify pure α-Si 3 N 4 commercial powder, having Y 2 O 3 and Al 2 O 3 additions; from 0, 2.5 and 5.0 wt% to 0, 1.5 and 3 wt%, respectively. Such powder admixtures were previously spray-dried at 160 o C in such a way that powder was thoroughly homogenized. Set sintering treatment included: 0-20 min holding time and 38 MPa axial load, sintering temperature of 1500 o C and heating rate of 300 o C/min. The maximum relative density developed on studied specimens ranged from 99.4 to 99.8% and could only be attained once the β-phase nucleated from the α-silicon nitride matrix. Obtained Si 3 N 4 composites combine both α- and β-phases. The later phase becomes evident trough the rod-like geometry, which forms throughout the presence of a liquid face. The largest hardness value developed (1588 Hv (20kgf) ) on studied ceramics (3M-series - 3 min) matched close to the corresponding counterpart found in literature (1600 Hv), the former developed in much shorter sintering times. Using X-ray diffraction XRD and scanning electron microscope SEM analyses, the two major phases of Si 3 N 4 were identified in the resultant microstructures. The morphology evolution of Si 3 N 4 particles as occurred upon SPS-sintering is analyzed.

  10. The effect of postproduction heat treatment on γ-TiAl alloys produced by the GTAW-based additive manufacturing process

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Yan; Cuiuri, Dominic; Li, Huijun; Pan, Zengxi, E-mail: zengxi@uow.edu.au; Shen, Chen

    2016-03-07

    Postproduction heat treatments were carried out on additively manufactured γ-TiAl alloys that were produced by using the gas tungsten arc welding (GTAW) process. The microstructural evolution and mechanical properties of both as-fabricated and heat-treated specimens were investigated to assess the effect of different heat treatment conditions, by using optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Neutron Diffraction and tensile tests. The results indicated that heat treatment promotes the formation of the γ phase in the majority region after heat treatment at 1200 °C for 24 h, while a fully lamellar structure was formed in the near-substrate zone. The response to heat treatment at 1060 °C/24 h was markedly different, producing a fine lamellar structure with differing sizes in the majority region and near-substrate zone. These various microstructural characteristics determined the mechanical properties of the heat-treated samples. The heat-treated samples at 1200 °C/24 h exhibited lower UTS and microhardness values but higher ductility than the as-fabricated samples without heat treatment, while the 1060 °C/24 h heat treatment resulted in higher UTS and microhardness values but lower ductility. Due to the homogenous microstructure in the majority region after each postproduction heat treatment, the tensile properties were similar for both the build direction (Z) and travel direction (Y), thereby minimising the anisotropy that is exhibited by the as-fabricated alloy prior to heat treatment.

  11. Influence of strontium as additive on corrosive-electrochemical behavior of alloy Al +6% lithium in NaCI electrolyte medium

    International Nuclear Information System (INIS)

    Ganiev, I.N.; Norova, M.T.; Nazarov, Kh.M.; Nikitin, V.I.; Karieva, Z.M.

    2005-01-01

    At various voltages, strontium settles down ahead of hydrogen, and the standard electrode potential equals -2,89B. Thus, in relation to aluminum- lithium an alloy Al-Li (6 % lithium) at electrode potential -1,020B, strontium is the anode. Taking into account anodic properties of strontium as additional and its solubility in aluminum-lithium a firm solution is formed, we have selected the following ratio of concentration of an alloying component, 0.01; 0.05; 0.1; 0.5 (mass %). It has perilously been shown, that potential of free corrosion in time, alloys alloyed by strontium, are exposed a little bit faster passivity, than not alloyed. The similar tendency has been observed in all three investigated medium: with the increase in concentration of strontium, the potential of free corrosion is displaced in positive area. Results potentiodynamic researches of alloys in the medium of electrolyte NaCI of various concentration of chlorines -ions the potential of corrosion is displaced in negative area that testifies to decrease of corrosion stability of allays, with growth of aggression of the corrosion medium. It proves to be true accounting speeds of corrosion of alloys from a catholic branch potentiodynamic curves. (author)

  12. 3D FE simulation of semi-finishing machining of Ti6Al4V additively manufactured by direct metal laser sintering

    Science.gov (United States)

    Imbrogno, Stano; Rinaldi, Sergio; Raso, Antonio; Bordin, Alberto; Bruschi, Stefania; Umbrello, Domenico

    2018-05-01

    The Additive Manufacturing techniques are gaining more and more interest in various industrial fields due to the possibility of drastically reduce the material waste during the production processes, revolutionizing the standard scheme and strategies of the manufacturing processes. However, the metal parts shape produced, frequently do not satisfy the tolerances as well as the surface quality requirements. During the design phase, the finite element simulation results a fundamental tool to help the engineers in the correct decision of the most suitable process parameters, especially in manufacturing processes, in order to produce products of high quality. The aim of this work is to develop a 3D finite element model of semi-finishing turning operation of Ti6Al4V, produced via Direct Metal Laser Sintering (DMLS). A customized user sub-routine was built-up in order to model the mechanical behavior of the material under machining operations to predict the main fundamental variables as cutting forces and temperature. Moreover, the machining induced alterations are also studied by the finite element model developed.

  13. Low-loss Z-type barium hexaferrite composites from nanoscale ZnAl2O4 addition for high-frequency applications

    Science.gov (United States)

    Zheng, Zongliang; Feng, Quanyuan; Harris, Vincent G.

    2018-05-01

    In this study, nanocrystalline ZnAl2O4 (ZA) were introduced to Z-type barium hexaferrite (Co2Z) and the effects of ZA addition upon the crystal-phase composition, microstructure, permeability and permittivity as well as losses characteristics over a wide frequency range of 10 MHz-1 GHz have been systematically investigated. With increasing ZA content (x) from 0 to 15 wt%, the permeability μ' at low frequencies decreased from 12.0 to 4.3, while the permittivity ɛ' was decreased from 27.4 to 10.7. Correspondingly, the frequency stability of permeability and permittivity were improved and the losses were effectively reduced. When x is in the range of 5-10 wt%, the magnetic loss tan δμ is in the order of 10-2 and the dielectric loss tan δɛ is in the order of 10-3 at 300 MHz, which is lower by one order of magnitude compared with that of undoped Co2Z. The modified magnetic and dielectric properties are closely related to the changing phase composition and microstructure.

  14. Usage of ATND method to determination of mechanical properties of AlMg10 alloy with complex additive of SbNiCr

    Directory of Open Access Journals (Sweden)

    J. Pezda

    2009-07-01

    Full Text Available Aluminum alloys with magnesium are commonly used in foundry industry due to lower density and higher corrosion resistance, comparing with silumins. Complicated shapes of produced alloys, differences in wall thickness and operation under changing loads require performing quality control as early as in stage of their preparation (melting. To register crystallization processes and monitor a phenomena arisen in result of the crystallization, are implemented methods based on analysis of temperature change (ATD, DTA. In the paper is present an attempt of usage of the ATND method (Thermal-Voltage-Derivative Analysis to registration of crystallization process of the investigated alloy. Obtained results concern registration of the crystallization process, strength and fatigue tests of the material, and visual observation of morphology of alloy’s fracture after static tensile test. Performed regression analysis has enabled implementation of changeable values of characteristic points of the ATND method to estimation of mechanical properties of the AlMg10 alloy with SbNiCr additive.

  15. Corrosion behavior of Mg–5Al based magnesium alloy with 1 wt.% Sn, Mn and Zn additions in 3.5 wt.% NaCl solution

    Directory of Open Access Journals (Sweden)

    Nguyen Dang Nam

    2014-06-01

    Full Text Available The corrosion properties of four Mg–5Al alloys with M-alloying elements (tin, manganese and zinc in a 3.5 wt.% NaCl solution were examined using electrochemical tests and surface analyses. The electrochemical results indicated that the addition of 1 wt.% M metal decreased the corrosion rate and hydrogen evolution rate of the Mg–5Al specimens. Moreover, the addition of 1Zn resulted in having the best corrosion resistance due to the interaction of Zn oxide with Mg and Al oxides which acted as a corrosion barrier.

  16. Tortuosity and calcification of the splenic artery. More than an additional finding; Schlaengelung und Verkalkung der Milzarterie im Roentgenbild. Mehr als ein Nebenbefund

    Energy Technology Data Exchange (ETDEWEB)

    Golder, W.A. [SELARL Association d' Imagerie Medicale, Troyes (France)

    2008-11-15

    Tortuosity of the splenic artery and calcification of the vessel wall are typical additional findings on plain abdominal x-ray. The combination of both anomalies is common in elderly persons presenting without symptoms of splenic ischemia. Its pathogenesis is thought to be multifactorial. In infancy and childhood, the splenic artery is stretched in its entire course. A growing difference between the length of the vessel and the distance between its origin and the splenic hilum gives rise to tortuosity. The artery's proximal segment is involved more frequently and more severely than the distal one. The tortuous route of the vessel is accentuated by the direction of its major branches, which is roughly perpendicular to the main trajectory. Neither tortuosity nor calcification should be taken to be risk factors for the comparatively common splenic artery aneurysm. Calcific deposits are not confined to the media but are also detected in the intima of the vascular wall. Critical narrowings of the lumen arising on the calcium deposits are not observed. Calcifying atherosclerosis of the splenic artery is comparable to medial sclerosis of the peripheral arteries frequently noticed in diabetics and dialysis patients. Only the less important calcification of the intima may be attributed to mechanisms of the hydrohemodynamic theory of atherosclerosis. The spleen's blood storage capacity may contribute to the characteristic age-dependent alterations of the shape and course of the splenic artery. (orig.) [German] Die Schlaengelung der Milzarterie und Verkalkungen in der Wand des Gefaesses sind ein typischer Nebenbefund bei der Roentgenuntersuchung des Abdomens. Die Kombination wird v. a. bei Senioren beobachtet, ohne dass Symptome einer Mangelperfusion der Milz fassbar sind. Bei der Pathogenese wirken eine Reihe verschiedener Faktoren zusammen. Im Kindesalter verlaeuft die A. lienalis stets gestreckt. Die zunehmende Schlaengelung wird durch die wachsende Differenz

  17. Characterization of geopolymer fly-ash based foams obtained with the addition of Al powder or H{sub 2}O{sub 2} as foaming agents

    Energy Technology Data Exchange (ETDEWEB)

    Ducman, V., E-mail: vilma.ducman@zag.si; Korat, L.

    2016-03-15

    Recent innovations in geopolymer technology have led to the development of various different types of geopolymeric products, including highly porous geopolymer-based foams, which are formed by the addition of foaming agents to a geopolymer fly-ash based matrix. These agents decompose, or react with the liquid matrix or oxygen in the matrix, resulting in the release of gases which form pores prior to the hardening of the gel. The hardened structure has good mechanical and thermal properties, and can therefore be used for applications in acoustic panels and in lightweight pre-fabricated components for thermal insulation purposes. This study presents the results of the pore-forming process in the case when two different foaming agents, i.e. aluminium powder amounting to 0.07, 0.13 and 0.20 mass. % and H{sub 2}O{sub 2} amounting to 0.5, 1.0, 1.5 and 2.0 mass. %, were added to a fly-ash geopolymer matrix. The physical, mechanical, and microstructural properties of the thus obtained foams, and the effects of the type and amount of the added foaming agent, are presented and discussed. Highly porous structures were obtained in the case of both of the investigated foaming agents, with overall porosities up to 59% when aluminium powder was added, and of up 48% when H{sub 2}O{sub 2} was added. In the latter case, when 2% of the H{sub 2}O{sub 2} foaming agent was added, finer pores (with diameters up to 500 μm) occurred in the structure, whereas somewhat larger pores (some had diameters greater than 1 mm) occurred when the same amount of aluminium powder was added. The mechanical properties of the investigated foams depended on their porosity. In the case of highly porous structures a compressive strength of 3.3 MPa was nevertheless achieved for the samples containing 0.2% of aluminium powder, and 3.7 MPa for those containing 2.0% of H{sub 2}O{sub 2}. - Highlights: • Preparation of geopolymer foams based on fly ash with the addition of Al powder or H{sub 2}O{sub 2} as

  18. Oxy-schorl, Na(Fe2+2Al)Al6Si6O18(BO3)3(OH)3O, a new mineral from Zlatá Idka, Slovak Republic and Přibyslavice, Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Bačík, P.; Cempírek, J.; Uher, P.; Novák, M.; Ozdín, D.; Filip, J.; Škoda, R.; Breiter, Karel; Klementová, Mariana; Ďuďa, R.; Groat, L. A.

    2013-01-01

    Roč. 98, 2/3 (2013), s. 485-492 ISSN 0003-004X Institutional support: RVO:67985831 ; RVO:68378271 Keywords : Oxy-schorl * tourmaline-supergroup minerals * new mineral * electron microanalysis * crystal-structure refinement * Přibyslavice * Zlatá Idka Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.059, year: 2013

  19. Liquid phase surface melting of AA8011 aluminum alloy by addition of Al/Al{sub 2}O{sub 3} nano-composite powders synthesized by high-energy milling

    Energy Technology Data Exchange (ETDEWEB)

    Sohi, M. Heydarzadeh [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Hojjatzadeh, S.M.H., E-mail: Hojatzadeh@yahoo.com [Department of Welding, Science and Research Branch, Azad University, Tehran (Iran, Islamic Republic of); Moosavifar, Sh. S.; Heshmati-Manesh, S. [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)

    2014-09-15

    Highlights: • Aluminum matrix composite layers reinforced with alumina particles were fabricated. • Non milled powders caused porosity in the microstructures because of poor wettability. • The ball milling of powders was significantly improved the wettability of nano ceramic particles. • The micro hardness of the layers was approximately 3 times greater than that of the base metal. - Abstract: Poor wettability of particles is an obstacle in formation of sound composite layer via surface melting. Pre-coating of particles with metallic material by different techniques, such as ball milling may enhance the wettability of the particles with molten metal. In this study, composite surface layers containing Al{sub 2}O{sub 3} particles were fabricated on the surface of AA8011 aluminum substrates by tungsten inert gas (TIG) surface melting using preplaced layers of Al/Al{sub 2}O{sub 3} powder mixtures in two different forms: (1) a mixture of 40 wt% Al and 60 wt% of 50 nm Al{sub 2}O{sub 3} powders and (2) a mixture obtained by mechanical alloying of 40 wt% Al and 60 wt% of 60 μm Al{sub 2}O{sub 3} powders. Morphology evolution of powders during ball milling and the microstructure of the fabricated composite layers were studied through conventional characterization techniques, such as optical microscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD). Microhardness measurements were also performed across the alloyed zone. The results indicated that the layer fabricated by the second route showed a defect free structure with a more uniform distribution of Al{sub 2}O{sub 3} particles in comparison with the layer obtained by the first route. It was also noticed that the uniform dispersion of Al{sub 2}O{sub 3} particles in the fabricated layer increased the hardness to 133 HV which was over 3 times of that of the base metal.

  20. Influence of Al addition on the thermal stability and mechanical properties of Fe76.5-xCu1Si13.5b9Alx amorphous alloys

    Directory of Open Access Journals (Sweden)

    Sun Y.Y.

    2012-01-01

    Full Text Available This paper fabricated Fe76.5-xCu1Si13.5B9Alx (x=0,1,2,3,5,7 at.% amorphous ribbons using singleroller melt-spinning method. The effect of Al content on the thermal stability and mechanical properties was investigated. The results indicated that Al addition have little effect on the amorphous formation ability of the alloys. On the other hand, increasing the Al content can substantially increase Tx2, which corresponds to the crystallization of Fe borides. Nanoindentation tests indicated that hardness of the alloys increase slightly with increasing the Al content, and Young’s modulus has a complicated relationship with the Al content.

  1. Zr O/sub 2/ and ZrSiO/sub 4/ addition influence in mechanical resistance and thermical shock of Al/sub 2/TiO/sub 5/

    Energy Technology Data Exchange (ETDEWEB)

    Marinho, P A; Longo, E; Varela, J A; Pandolfelli, V C

    1985-01-01

    The ZrO/sub 2/ and ZrSiO/sub 4/ addition on the Al/sub 2/O/sub 3/TiO/sub 2/ composition showed to be efficient on higher the mechanical and thermal shock resistence of the compound formed. The reactions that formed the phases and the influence of the ones on thermal and mechanical behaviour of the compound Al/sub 2/TiO/sub 5/ were discussed. (L.M.J.).

  2. Effect of build geometry on the β-grain structure and texture in additive manufacture of Ti-6Al-4V by selective electron beam melting

    International Nuclear Information System (INIS)

    Antonysamy, A.A.; Meyer, J.; Prangnell, P.B.

    2013-01-01

    With titanium alloys, the solidification conditions in Additive Manufacturing (AM) frequently lead to coarse columnar β-grain structures. The effect of geometry on the variability in the grain structure and texture, seen in Ti-6Al-4V alloy components produced by Selective Electron Beam Melting (SEBM), has been investigated. Reconstruction of the primary β-phase, from α-phase EBSD data, has confirmed that in bulk sections where in-fill “hatching” is employed growth selection favours columnar grains aligned with an β direction normal to the deposited powder layers; this results in a coarse β-grain structure with a strong β fibre texture (up 8 x random) that can oscillate between a near random distribution around the fibre axis and cube reinforcement with build height. It is proposed that this behaviour is related to the highly elongated melt pool and the raster directions alternating between two orthogonal directions every layer, which on average favours grains with cube alignment. In contrast, the outline, or “contour”, pass produces a distinctly different grain structure and texture resulting in a skin layer on wall surfaces, where nucleation occurs off the surrounding powder and growth follows the curved surface of the melt pool. This structure becomes increasingly important in thin sections. Local heterogeneities have also been found within different section transitions, resulting from the growth of skin grain structures into thicker sections. Texture simulations have shown that the far weaker α-texture (∼ 3 x random), seen in the final product, arises from transformation on cooling occurring with a near random distribution of α-plates across the 12 variants possible from the Burgers relationship. - Highlights: • Distinctly different skin and bulk structures are produced by the contour and hatching passes. • Bulk sections contain coarse β-grains with a fibre texture in the build direction. • This oscillates between a random distribution

  3. Effect of build geometry on the β-grain structure and texture in additive manufacture of Ti-6Al-4V by selective electron beam melting

    Energy Technology Data Exchange (ETDEWEB)

    Antonysamy, A.A., E-mail: alphons.antonysamy@GKNAerospace.com [Additive Manufacturing Centre, GKN Aerospace, P.O. Box 500, Golf Course Lane, Filton, BS34 9 AU (United Kingdom); Meyer, J., E-mail: jonathan.meyer@eads.com [EADS Innovation Works, 20A1 Building, Golf Course Lane, Filton, Bristol, BS997AR (United Kingdom); Prangnell, P.B., E-mail: philip.prangnell@manchester.ac.uk [School of Materials, University of Manchester, Manchester M13 9PL (United Kingdom)

    2013-10-15

    With titanium alloys, the solidification conditions in Additive Manufacturing (AM) frequently lead to coarse columnar β-grain structures. The effect of geometry on the variability in the grain structure and texture, seen in Ti-6Al-4V alloy components produced by Selective Electron Beam Melting (SEBM), has been investigated. Reconstruction of the primary β-phase, from α-phase EBSD data, has confirmed that in bulk sections where in-fill “hatching” is employed growth selection favours columnar grains aligned with an <001> {sub β} direction normal to the deposited powder layers; this results in a coarse β-grain structure with a strong < 001 > {sub β} fibre texture (up 8 x random) that can oscillate between a near random distribution around the fibre axis and cube reinforcement with build height. It is proposed that this behaviour is related to the highly elongated melt pool and the raster directions alternating between two orthogonal directions every layer, which on average favours grains with cube alignment. In contrast, the outline, or “contour”, pass produces a distinctly different grain structure and texture resulting in a skin layer on wall surfaces, where nucleation occurs off the surrounding powder and growth follows the curved surface of the melt pool. This structure becomes increasingly important in thin sections. Local heterogeneities have also been found within different section transitions, resulting from the growth of skin grain structures into thicker sections. Texture simulations have shown that the far weaker α-texture (∼ 3 x random), seen in the final product, arises from transformation on cooling occurring with a near random distribution of α-plates across the 12 variants possible from the Burgers relationship. - Highlights: • Distinctly different skin and bulk structures are produced by the contour and hatching passes. • Bulk sections contain coarse β-grains with a < 001 > fibre texture in the build direction. • This

  4. MTBE experts' discussion: Environmental pollution from MTBE fuel additives. Proceedings; MTBE-Fachgespraech: Umweltbelastungen durch die Nutzung von MTBE (Methyl-tertiaer-butylether) als Kraftstoffzusatz. Tagungsband

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    MTBE is a volatile, water-soluble, oxygen-containing liquid with a high octane rating. It hardly absorbs to the soil matrix, is hardly degradable by biological means, and moves in groundwater at practically the same speed as the groundwater itself. This makes it an important groundwater hazard. The main problem is the low taste and smell threshold concentration of MTBE, because of which contaminated water is unfit for drinking. MTBE has been used as a fuel additive in the USA since the seventies and in Germany since the eighties for a better antiknock rating. MTBE concentrations depend on the fuel quality, ranging from 0.3 percent in normal gasoline and 1.6 percent in super gasoline to 6-12 percent by volume in SuperPlus and Optimax fuels. At this conference, which comprised nine lectures and a round of detailed discussions, measured concentrations of MTBE in air, precipitations, surface water and groundwater were presented, and the possibilities of modelling were discussed. The attendants of the meeting agreed that in view of the available data and at the present state of knowledge concerning the sources and fate of MTBE in environmental media, MTBE cannot be excluded as a groundwater pollutant. (orig.) [German] MTBE ist eine leichtfluechtige, gut wasserloesliche, sauerstoffhaltige Fluessigkeit mit hoher Oktanzahl. Es sorbiert fast nicht an die Bodenmatrix, ist sehr schlecht biologisch abbaubar und bewegt sich im Grundwasser praktisch mit der gleichen Geschwindigkeit wie das Grundwasser selbst. Aufgrund dieser Eigenschaften stellt MTBE eine Gefahr fuer das Grundwasser dar. Problematisch aus Sicht der Wasserversorgung ist die niedrige Geruchs- und Geschmacksschwelle von MTBE, weshalb kontaminiertes Wasser nicht mehr als Trinkwasser brauchbar ist. MTBE wird seit Mitte der 70er Jahre in den USA und seit Anfang der 80er Jahre in Deutschland dem Benzin zugesetzt, um die Klopffestigkeit zu verbessern. Der MTBE-Gehalt haengt von der Benzin-Qualitaet ab: Waehrend

  5. Comparative analysis of Nb and Ti addition in the Cu-11,8%wt.Al-0,5%wt.Be e Cu-11,8%wt.Al-3,0%wt.Ni shape memory alloy

    International Nuclear Information System (INIS)

    Silva Junior, M.Q. da; Oliveira, G.D. de

    2014-01-01

    The system of the Cu-Al alloys shape memory alloy have been the subject of many studies due to a wide range of possible applications and relatively low cost, and the chemical composition of the main factors that determine the properties of these properties. This work analyzed the influence of Nb and Ti elements in Cu-11,8Al-0,5Be and Cu-11,8Al-3,0Ni alloy. The alloys are obtained by melting and passed through homogenizing heat treatment followed by water quenching at 30°C. The samples were characterized by Microscopy Optical, X-ray Diffraction and Microhardness testing. The alloys showed fine precipitates of second phase homogeneously distributed in the matrix that provides improvement in the properties of these alloys. (author)

  6. Influence of ZrB2 addition on microstructural development and microhardness of Ti-SiC clad coatings on Ti6Al4V substrate

    CSIR Research Space (South Africa)

    Farotade, GA

    2017-08-01

    Full Text Available The microstructural features and microhardness of ZrB(sub2) reinforced Ti-SiC coatings on Ti-6Al-4V substrate were studied.The deposition of these coatings was achieved via laser cladding technique. A 4.0 KW fiber delivered Nd: YAG laser was used...

  7. Effects of Nb addition on icosahedral quasicrystalline phase formation and glass-forming ability of Zr--Ni--Cu--Al metallic glasses

    International Nuclear Information System (INIS)

    Fan, Cang; Li, Chunfei; Inoue, Akihisa; Haas, Volker

    2001-01-01

    This work shows that the crystallization process of Zr--Ni--Cu--Al metallic glass is greatly influenced by adding Nb as an alloying element. Based on the results of the differential scanning calorimetry experiments for metallic glasses Zr 69-x Nb x Ni 10 Cu 12 Al 9 (x=0--15at.%), the crystallization process takes place through two individual stages. For Zr 69 Ni 10 Cu 12 Al 9 (x=0), metastable hexagonal ω-Zr and a small fraction of tetragonal Zr 2 Cu are precipitated upon completion of the first exothermic reaction. Contrary to this alloy, the precipitation of a nanoquasicrystalline phase is detected when 5--10 at.% Nb is added. Furthermore, the crystallization temperature T x , supercooled liquid region ΔT x and reduced temperature T g /T L (T g is the glass transition temperature, T L the liquidus temperature) increase with increasing Nb content. These results indicate that adding Nb content to Zr--Ni--Cu--Al metallic glasses not only induces quasicrystalline phase formation, but also enhances glass-forming ability. Copyright 2001 American Institute of Physics

  8. Kampelite, Ba3Mg1.5Sc4(PO4)6(OH)3·4H2O, a new very complex Ba-Sc phosphate mineral from the Kovdor phoscorite-carbonatite complex (Kola Peninsula, Russia)

    Science.gov (United States)

    Yakovenchuk, Victor N.; Ivanyuk, Gregory Yu.; Pakhomovsky, Yakov A.; Panikorovskii, Taras L.; Britvin, Sergei N.; Krivovichev, Sergey V.; Shilovskikh, Vladimir V.; Bocharov, Vladimir N.

    2018-02-01

    Kampelite, Ba3Mg1.5Sc4(PO4)6(OH)3·4H2O, is a new Ba-Sc phosphate from the Kovdor phoscorite-carbonatite complex (Kola Peninsula, Russia). It is orthorhombic, Pnma, a = 11.256(1), b = 8.512(1), c = 27.707(4) Å, V = 2654.6(3) Å3 and Z = 4 (from powder diffraction data) or a = 11.2261(9), b = 8.5039(6), c = 27.699(2) Å, V = 2644.3(3) Å3 (from single-crystal diffraction data). The mineral was found in a void within the calcite-magnetite phoscorite (enriched in hydroxylapatite and Sc-rich baddeleyite) inside the axial zone of the Kovdor phoscorite-carbonatite pipe. Kampelite forms radiated aggregates (up to 1.5 mm in diameter) of platy crystals grown on the surfaces of crystals of quintinite-2 H in close association with pyrite, bobierrite and quintinite-3 R. Kampelite is colourless, with a pearly lustre and a white streak. The cleavage is perfect on {001}, the fracture is smooth. Mohs hardness is about 1. In transmitted light, the mineral is colourless without pleochroism or dispersion. Kampelite is biaxial + (pseudouniaxial), α ≈ β = 1.607(2), γ = 1.612(2) (589 nm), and 2 V calc = 0°. The calculated and measured densities are 3.28 and 3.07(3) g·cm-3, respectively. The mean chemical composition determined by electron microprobe is: MgO 4.79, Al2O3 0.45, P2O5 31.66, K2O 0.34, Sc2O3 16.17, Mn2O3 1.62, Fe2O3 1.38, SrO 3.44, and BaO 29.81 wt%. The H2O content estimated from the crystal-structure refinement is 7.12 wt%, giving a total of 96.51 wt%. The empirical formula calculated on the basis of P = 6 apfu (atoms per formula unit) is (Ba2.62Sr0.45K0.10Ca0.06)Σ3.23Mg1.60Mn0.28(Sc3.15Fe3+ 0.23Al0.12)Σ3.50(PO4)6(OH)2.61·4.01H2O. The simplified formula is Ba3Mg1.5Sc4(PO4)6(OH)3·4H2O. The mineral easily dissolves in 10% cold HCl. The strongest X-ray powder-diffraction lines [listed as d in Å ( I) ( hkl)] are as follows: 15.80(100)(001), 13.86(45)(002), 3.184(18)(223), 3.129(19)(026), 2.756(16)(402), 2.688(24)(10 10). The crystal structure of kampelite was

  9. Effects of samarium (Sm) additions on the microstructure and mechanical properties of as-cast and hot-extruded Mg-5 wt%Al-3 wt%Ca-based alloys

    International Nuclear Information System (INIS)

    Son, Hyeon-Taek; Lee, Jae-Seol; Kim, Dae-Guen; Yoshimi, Kyosuke; Maruyama, Kouichi

    2009-01-01

    Samarium (Sm) additions to as-cast Mg-5Al-3Ca-based alloys result in changes, such as equiaxed grains and a refined grain size. The microstructure of as-cast Mg-5Al-3Ca-xSm alloys consists of an α-Mg matrix, a (Mg, Al) 2 Ca eutectic phase, and an Al 2 Sm intermetallic compound. In as-cast alloys, the (Mg, Al) 2 Ca eutectic phase was located at grain boundaries with a chain structure, and the Al 2 Sm intermetallic compounds were homogeneously distributed at the α-Mg matrix and grain boundaries. The eutectic phase of the extruded alloys was elongated in the extrusion direction and crushed into fine particles because of severe deformation during hot extrusion, and the grain size was refined with an increased amount of Sm addition. The maximum values of the yield strength and tensile strength were 313 MPa and 330 MPa at 2 wt%Sm alloy content, respectively

  10. Kamarizaite, Fe{3/3+}(AsO4)2(OH)3 · 3H2O, a new mineral species, arsenate analogue of tinticite

    Science.gov (United States)

    Chukanov, N. V.; Pekov, I. V.; Möckel, S.; Mukhanova, A. A.; Belakovsky, D. I.; Levitskaya, L. A.; Bekenova, G. K.

    2010-12-01

    Kamarizaite, a new mineral species, has been identified in the dump of the Kamariza Mine, Lavrion mining district, Attica Region, Greece, in association with goethite, scorodite, and jarosite. It was named after type locality. Kamarizaite occurs as fine-grained monomineralic aggregates (up to 3 cm across) composed of platy crystals up to 1 μm in size and submicron kidney-shaped segregations. The new mineral is yellow to beige, with light yellow streak. The Mohs hardness is about 3. No cleavage is observed. The density measured by hydrostatic weighing is 3.16(1) g/cm3, and the calculated density is 3.12 g/cm3. The wavenumbers of absorption bands in the IR spectrum of kamarizaite are (cm-1; s is strong band, w is weak band): 3552, 3315s, 3115, 1650w, 1620w, 1089, 911s, 888s, 870, 835s, 808s, 614w, 540, 500, 478, 429. According to TG and IR data, complete dehydration and dehydroxylation in vacuum (with a weight loss of 15.3(1)%) occurs in the temperature range 110-420°C. Mössbauer data indicate that all iron in kamarizaite is octahedrally coordinated Fe3+. Kamarizaite is optically biaxial, positive: n min = 1.825, n max = 1.835, n mean = 1.83(1) (for a fine-grained aggregate). The chemical composition of kamarizaite (electron microprobe, average of four point analyses) is as follows, wt %: 0.35 CaO, 41.78 Fe2O3, 39.89 As2O5, 1.49 SO3, 15.3 H2O (from TG data); the total is 98.81. The empirical formula calculated on the basis of (AsO4,SO4)2 is Ca0.03Fe{2.86/3+} (AsO4)1.90(SO4)0.10(OH)2.74 · 3.27H2O. The idealized formula is Fe{3/3+}(AsO4)2(OH)3 · 3H2O. Kamarizaite is an arsenate analogue of orthorhombic tinticite, space group Pccm, Pcc2, Pcmm, Pcm21, or Pc2 m; a = 21.32(1), b = 13.666(6), c =15.80(1) Å, V= 4603.29(5) Å3, Z= 16. The strongest reflections of the X-ray powder diffraction pattern [ bar d , Å ( I, %) ( hkl)] are: 6.61 (37) (112, 120), 5.85 (52) (311), 3.947 (100) (004, 032, 511), 3.396 (37) (133, 431), 3.332 (60) (314), 3.085 (58) (621, 414, 324

  11. Synthesis and characterization of Al2O3NbC composite and the effect of Y2O3 addition on its sintering

    International Nuclear Information System (INIS)

    Pasotti, Rosa Maria da Rocha

    1999-01-01

    Alumina composites containing ceramic particles have been intensively studied because they show improved mechanical properties and some advantages over fibres and whiskers based composites mainly for processing. The embedment of NbC particles in an Al 2 O 3 matrix has been investigated in this work. Composite materials were obtained by the conventional ceramic processing with compositions Al 2 O 3 -x NbC where x=10, 20, and 40 weight %. Materials were sintered in argon at 1650 deg C/30 min, and at 1750 deg C/15min using a graphite resistance furnace. Three sets of samples were processed: containing NbC powder as received; containing NbC powder milled for 30 h; and containing 3 weight % of Y 2 O 3 added to the Al 2 O 3 matrix. After sintering samples were analysed to evaluate the densification grade. Phases were determined by X-ray diffraction, and samples were analysed by optical microscopy, scanning electron microscopy and transmission electron microscopy to observe the microstructure features. Hardness and fracture toughness at room temperature were also determined by the indentation method, and the sintering kinetic was evaluated by dilatometry. The present work shows that Al 2 O 3 -NbC composite can be produced by using pressureless sintering, leading to materials with densities higher than 95% of the theoretical density for all composites containing NbC and sintered at 1750 deg C. The same result can be obtained for composites containing 10 and 20 weight % of NbC, and sintered at temperatures as low as 1650 deg C. Higher concentration of NbC in the Al 2 O 3 matrix promotes an improvement of fracture toughness. Samples with 40-wt % of NbC show K IC equals to 4.5 MPa.m 1/2 . This value is compared to the ones previously determined for Al 2 O 3 - TiC composites, available commercially and used in ceramic cutting-tools. (author)

  12. Effect of Al-R (R = Dy or Tb) master alloys addition on the properties of magnets made of Nd14.7R1.3Fe75Co2B7

    International Nuclear Information System (INIS)

    Savchenko, A.G.; Ryazantsev, V.A.; Skuratovskij, Yu.E.; Lileev, A.S.; Menushenkov, V.P.

    2000-01-01

    The hysteresis characteristics of caked constant magnets of the (Nd, R)-(Fe, Co)-B system alloys with the Al-R master easily-melting additions, wherein R is Dy or Tb, are studied. High efficiency of the mixture method by obtaining highly-coercive constant magnets on the basis of the studied systems alloys is shown. The hysteresis properties of the caked constant magnets may be changed within sufficiently wide limits by varing the number and composition of the alloys mixture components. The effect of the Al-Dy and Al-Tb additions on properties of constant magnets of uniform nominal composition is compared. Higher efficiency of master alloys on the Tb basis is noted; the coercive force and energy characteristics of this series of caked constant magnets is higher [ru

  13. Effect of Y additions on the solidification behavior of a copper mold cast CuZrAl alloy with high oxygen content

    International Nuclear Information System (INIS)

    Coury, F.G.; Batalha, W.; Botta, W.J.; Bolfarini, C.; Kiminami, C.S.

    2014-01-01

    Bulk glassy samples of the CuAlZr system were produced by copper mold casting in the form of wedges with different amounts of yttrium (0 , 0.3 and 2 at%) , the processing conditions led to high oxygen contents on the samples (1000ppm). A reportedly good glass-former composition was chosen as the base alloy, it’s nominal composition is Cu47Zr45Al8. This study aimed to understand the influence of oxygen and yttrium in the solidification of these alloys. The samples were analyzed by scanning and transmission electron microscopy, differential scanning calorimetry and X-Ray diffraction. The sequence of formation of crystalline phases in these alloys was determined as a function of the different cooling rates inherent in the process. It was observed that the formation of CuZr2 phase was inhibited in samples with Y allowing the production of a fully glassy 8mm. (author)

  14. Preparation of Al-SBA-15 Pellets with Low Amount of Additives: Effect of Binder Content on Texture and Mechanical Properties. Application to Friedel-Crafts Alkylation

    Czech Academy of Sciences Publication Activity Database

    Topka, Pavel; Karban, Jindřich; Soukup, Karel; Jirátová, Květa; Šolcová, Olga

    2011-01-01

    Roč. 168, č. 1 (2011), s. 433-440 ISSN 1385-8947 R&D Projects: GA ČR GA104/09/0694; GA AV ČR KAN400720701 Institutional research plan: CEZ:AV0Z40720504 Keywords : mesoporous aluminosilicates * pellets * Al-SBA-15 Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 3.461, year: 2011

  15. The variable potency of TiB{sub 2} nucleant particles in the grain refinement of aluminium by Al-Ti-B additions

    Energy Technology Data Exchange (ETDEWEB)

    Quested, T.E.; Greer, A.L. [Cambridge Univ. (United Kingdom). Dept. of Metallurgy and Materials Science; Cooper, P.S. [London and Scandinavian Metallurgical Co. Ltd., Rotherham (United Kingdom)

    2002-07-01

    The development of Al-Ti-B grain-refiners is outlined. The relationships between nucleant particle potency, number and volume efficiencies, and overall refiner performance are explored. The importance of the particle size distribution is illustrated using hypothetical log-normal distributions in a thermal model for grain refinement which uses a free-growth criterion for grain initiation. In this way the degree of optimization of a current commercial refiner is assessed. (orig.)

  16. Thermodynamics of the interaction of UO2 with carbon in the presence of the additives Al2O3XSiO2, SiC, and UC2

    International Nuclear Information System (INIS)

    Khromov, Y.F.; Suistunov, D.E.; Zhmurov, S.A.

    1986-01-01

    The authors investigate the thermodynamics of the interaction of UO 2 with C in the presence of the additives, viz., aluminosilicate Al 2 O 3 XSiO 2 , silicon carbide, and uranium dicarbide. The studies were carried out according to the Knudsen method. The characteristics of the components and the experimental systems in contact with carbon are presented. The obtained experimental and calculated thermodynamic data permit one to describe the interaction process of uranium-dioxide-containing additives with carbon

  17. Improvement of photoluminescence properties and thermal stability of Y2.9Ce0.1Al5−xSixO12 phosphors with Si3N4 addition

    International Nuclear Information System (INIS)

    Zhang, Fangfang; Song, Kaixin; Jiang, Jun; Wu, Song; Zheng, Peng; Huang, Qingming; Xu, Junming; Qin, Huibin

    2014-01-01

    Highlights: • Y 2.9 Ce 0.1 Al 5−x Si x O 12 phosphors were prepared by solid-state reaction in reduced air ambience. • Si 4+ could be incorporated into the host lattice of Y 3 Al 5 O 12 through partial occupation of the Al 3+ sites. • Si 3 N 4 addition can improve photoluminescence efficiency and thermal stability of Y 3 Al 5 O 12 :Ce. - Abstract: A series of Si 3 N 4 doping Y 2.9 Ce 0.1 Al 5−x Si x O 12−3x/2 N 4x/3 phosphors were prepared by solid-state reaction in 95%N 2 –5%H 2 reduced air ambience. The XRD characteristics plus Rietveld refinement results shows that the as-sintered powders are unique crystal phase with the same crystal structure of Y 3 Al 5 O 12 (PDF No. 79-1891). The N element was not detected by the analysis of X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectrum (EDS). The photoluminescence spectra (PL and PLE) tests show that the exciting and emitting intensity of PLE and PL gradually increase due to the increase of Si 3 N 4 concentration. Meanwhile, the phosphorescence decay times are prolonged from 45 ns (x = 0) to 78 ns (x = 0.3), under the monitor of 530 nm wavelength. The thermoluminescence tests (TL) confirm the thermal stability of as-phosphors with Si 3 N 4 addition is much better than that of the pristine Y 2.9 Ce 0.1 Al 5 O 12 phosphors

  18. Investigation of laser cladding high temperature anti-wear composite coatings on Ti6Al4V alloy with the addition of self-lubricant CaF2

    International Nuclear Information System (INIS)

    Xiang, Zhan-Feng; Liu, Xiu-Bo; Ren, Jia; Luo, Jian; Shi, Shi-Hong; Chen, Yao; Shi, Gao-Lian; Wu, Shao-Hua

    2014-01-01

    Highlights: • A novel high temperature self-lubricating wear-resistant coating was fabricated. • TiC carbides and self-lubricant CaF 2 were “in situ” synthesized in the coating. • The coating with the addition of CaF 2 possessed superior properties than without. - Abstract: To improve the high-temperature tribological properties of Ti–6Al–4V alloy, γ-NiCrAlTi/TiC and γ-NiCrAlTi/TiC/CaF 2 coatings were fabricated on Ti–6Al–4V alloy by laser cladding. The phase compositions and microstructure of the coatings were investigated using X-ray diffraction (XRD) and scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS). The tribological behaviors were evaluated using a ball-on-disk tribometer from ambient temperature to 600 °C under dry sliding wear conditions and the corresponding wear mechanisms were discussed. The results indicated that the γ-NiCrAlTi/TiC/CaF 2 coating consisted of α-Ti, the “in situ” synthesized TiC block particles and dendrite, γ-NiCrAlTi solid solution and spherical CaF 2 particles. The wear rates of γ-NiCrAlTi/TiC/CaF 2 coating were decreased greatly owing to the combined effects of the reinforced carbides and continuous lubricating films. Furthermore, the friction coefficients of γ-NiCrAlTi/TiC/CaF 2 coating presented minimum value of 0.21 at 600 °C, which was reduced by 43% and 50% compared to the substrate and γ-NiCrAlTi/TiC coating respectively. It was considered that the γ-NiCrAlTi/TiC/CaF 2 coating exhibited excellent friction-reducing and anti-wear properties at high temperature

  19. Investigation of laser cladding high temperature anti-wear composite coatings on Ti6Al4V alloy with the addition of self-lubricant CaF{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, Zhan-Feng [School of Mechanical and Electric Engineering, Soochow University, 178 East Ganjiang Road, Suzhou 215006 (China); Liu, Xiu-Bo, E-mail: liuxiubo@suda.edu.cn [School of Mechanical and Electric Engineering, Soochow University, 178 East Ganjiang Road, Suzhou 215006 (China); Ren, Jia; Luo, Jian; Shi, Shi-Hong; Chen, Yao [School of Mechanical and Electric Engineering, Soochow University, 178 East Ganjiang Road, Suzhou 215006 (China); Shi, Gao-Lian; Wu, Shao-Hua [Suzhou Institute of Industrial Technology, Suzhou 215104 (China)

    2014-09-15

    Highlights: • A novel high temperature self-lubricating wear-resistant coating was fabricated. • TiC carbides and self-lubricant CaF{sub 2} were “in situ” synthesized in the coating. • The coating with the addition of CaF{sub 2} possessed superior properties than without. - Abstract: To improve the high-temperature tribological properties of Ti–6Al–4V alloy, γ-NiCrAlTi/TiC and γ-NiCrAlTi/TiC/CaF{sub 2} coatings were fabricated on Ti–6Al–4V alloy by laser cladding. The phase compositions and microstructure of the coatings were investigated using X-ray diffraction (XRD) and scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS). The tribological behaviors were evaluated using a ball-on-disk tribometer from ambient temperature to 600 °C under dry sliding wear conditions and the corresponding wear mechanisms were discussed. The results indicated that the γ-NiCrAlTi/TiC/CaF{sub 2} coating consisted of α-Ti, the “in situ” synthesized TiC block particles and dendrite, γ-NiCrAlTi solid solution and spherical CaF{sub 2} particles. The wear rates of γ-NiCrAlTi/TiC/CaF{sub 2} coating were decreased greatly owing to the combined effects of the reinforced carbides and continuous lubricating films. Furthermore, the friction coefficients of γ-NiCrAlTi/TiC/CaF{sub 2} coating presented minimum value of 0.21 at 600 °C, which was reduced by 43% and 50% compared to the substrate and γ-NiCrAlTi/TiC coating respectively. It was considered that the γ-NiCrAlTi/TiC/CaF{sub 2} coating exhibited excellent friction-reducing and anti-wear properties at high temperature.

  20. Influence of grain size and additions of Al and Mn on the magnetic properties of non-oriented electrical steels with 3 wt. (% Si

    Directory of Open Access Journals (Sweden)

    Rodrigo Felix de Araujo Cardoso

    2008-03-01

    Full Text Available The influence of hot-band grain size and additions of aluminum and manganese on the magnetic properties of non-oriented grain (NOG low-carbon electrical steel with about 3 wt. (% Si were investigated using optical microscopy and X ray diffraction. The addition of manganese resulted in larger grains after final annealing. Coarse grains in the hot-band and addition of Mn led to a Goss orientation component after final annealing, which resulted in an increase in the magnetic permeability.

  1. Indirect improvement of high temperature mechanical properties of a Mg-based alloy Elektron21 by addition of AlN nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Daudin, R. [Univ. Grenoble Alpes, CNRS, SIMaP, F-38000 Grenoble (France); Terzi, S. [European Space Agency, ESTEC, TEC-TS, EPN Campus, CS20156, 38042 Grenoble Cedex 9 (France); Mallmann, C. [Univ. Grenoble Alpes, CNRS, SIMaP, F-38000 Grenoble (France); Martín, R. Sánchez [IMDEA Materials Institute, Tecnogetafe C/ Eric Kandel, 2, 28906 Getafe, Madrid (Spain); Lhuissier, P. [Univ. Grenoble Alpes, CNRS, SIMaP, F-38000 Grenoble (France); Boller, E.; Pacureanu, A. [European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble (France); Katsarou, L.; Dieringa, H. [Helmholtz-Zentrum Geesthacht, Magnesium Innovation Centre – MagIC, Max-Planck-Str. 1, 21502 Geesthacht (Germany); Salvo, L. [Univ. Grenoble Alpes, CNRS, SIMaP, F-38000 Grenoble (France)

    2017-03-14

    Magnesium being the lightest metal on earth used as a structural material, the design of the chemistry and the microstructures of Mg-based alloys has been developed over the years to always further ameliorate their mechanical properties. A supplementary option consists in adding ceramic nanoparticles to such alloys to design Mg-based metal matrix nanocomposites (MMNCs) displaying improvement of both strength and ductility. In practice however, careful attention is required to understand the fundamental mechanisms at the heart of the enhancement of these properties as they still remain quite uncertain and subjected to misleading interpretations. Here, high temperature (350 °C) strain rate jump tests in compression reveal an enhancement of 20–60% of the mechanical properties when AlN nano-particles are added to the Elektron21 alloy (Mg-2.8Nd-1.2Gd-0.4Zr-0.3Zn, in wt%). At the same time, nano-indentation investigations suppose that forest or Orowan strengthening, due to particles-dislocations interactions, is unlikely to occur. Instead, using complementary microstructural characterization techniques (scanning electron macroscopy, energy dispersive spectroscopy as well as micro- and nano-tomography), we show that AlN nano-particles physically and chemically interact with the alloy and modify the overall microstructure, in particular the intermetallic phase, at the origin of the improvement of the mechanical properties.

  2. The Effects of Sn Addition on the Microstructure and Surface Properties of Laser Deposited Al-Si-Sn Coatings on ASTM A29 Steel

    Science.gov (United States)

    Fatoba, Olawale S.; Akinlabi, Stephen A.; Akinlabi, Esther T.

    2018-03-01

    Aluminium and its alloys have been successful metal materials used for many applications like commodity roles, automotive and vital structural components in aircrafts. A substantial portion of Al-Fe-Si alloy is also used for manufacturing the packaging foils and sheets for common heat exchanger applications. The present research was aimed at studying the morphology and surface analyses of laser deposited Al-Sn-Si coatings on ASTM A29 steel. These Fe-intermetallic compounds influence the material properties during rapid cooling by laser alloying technique and play a crucial role for the material quality. Thus, it is of considerable technological interest to control the morphology and distribution of these phases in order to eliminate the negative effects on microstructure. A 3 kW continuous wave ytterbium laser system (YLS) attached to a KUKA robot which controls the movement of the alloying process was utilized for the fabrication of the coatings at optimum laser parameters. The fabricated coatings were investigated for its hardness and wear resistance performance. The field emission scanning electron microscope equipped with energy dispersive spectroscopy (SEM/EDS) was used to study the morphology of the fabricated coatings and X-ray diffractometer (XRD) for the identification of the phases present in the coatings. The coatings were free of cracks and pores with homogeneous and refined microstructures. The enhanced hardness and wear resistance performance were attributed to metastable intermetallic compounds formed.

  3. Microstructural study of Ni/γ-Al2O3 catalyst: addition effects of CeO2 on carbon dioxide reforming of methane

    International Nuclear Information System (INIS)

    Valentini, Antoninho; Probst, Luiz Fernando Dias; Carreno, Neftali L. V.; Leite, Edson R.; Pontes, Fenelon M.; Longo, Elson; Schreiner, Wido H.; Lisboa-Filho, Paulo N.

    2003-01-01

    The carbon dioxide reforming of methane was carried out over nickel catalysts supported on the γ-Al 2 O 3 /CeO 2 system prepared by wet impregnation. With the increase of the Co2 weight in the catalyst, a higher stability was observed in the catalytic activity, together with an excellent resistance to carbon deposition and a better Ni dispersion. The catalysts were characterized by means of surface area measurements, TPR, H 2 chemisorption, XRD, SEM, EDX, XPS and TEM. An interaction between Ni and CeO 2 was observed to the Ni/CeO 2 sample after activation in a H 2 atmosphere above 300 deg C. Such behavior has a significantly influence on the catalytic activity. (author)

  4. Effect of Concurrent ZnO Addition and AlF3 Reduction on the Elastic Properties of Tellurite Based Glass System

    Directory of Open Access Journals (Sweden)

    Haji Abdul Aziz Sidek

    2014-01-01

    Full Text Available New ternary zinc oxyfluorotellurite (ZOFT with the composition (ZnOx-(AlF3y-(TeO2z, where 5≤x<35; 5≤y≤25; 60≤z≤70, has been successfully prepared by the conventional rapid melt quenching technique. Density, molar volume, and glass transition temperature have been assessed for each ZOFT glass sample. The longitudinal and transverse ultrasonic waves propagated in each glass sample were measured using a MBS8020 ultrasonic data acquisition system at 5 MHz frequency and room temperature. The longitudinal modulus (L, shear modulus (G, Young’s modulus (E, bulk modulus (K, and Poisson’s ratio (σ are assessed from both velocity data and their respective density. The compositional dependence of the ultrasonic velocities and related parameters are discussed to understand the rigidity and compactness of the glass system studied.

  5. Synthesis of γ-Al2O3 nanowires through a boehmite precursor route

    Indian Academy of Sciences (India)

    has applications in absorbent, catalyst carrier and reinforce- ment of ceramic .... nia into the transparent solution, Al(OH)3 with colloidal form generates .... 99 1823. Zhou J, Deng S Z, Chen J, She J C and Xu N S 2002 Chem. Phys. Lett. 365 505.

  6. Effect of air annealing on the color center in Yb:Y3Al5O12 transparent ceramics with MgO as sintering additive

    Science.gov (United States)

    Lu, Zhongwen; Lu, Tiecheng; Wei, Nian; Zhang, Wei; Ma, Benyuan; Qi, Jianqi; Guan, Yongbing; Chen, Xingtao; Wu, Huajun; Zhao, Yu

    2015-09-01

    High quality Yb:Y3Al5O12 (YAG) transparent ceramics were fabricated by vacuum sintering with MgO as sintering aids. The Yb:YAG samples were annealed at 1250-1450 °C for 20 h in air. The experimental results showed that the transparency of Yb:YAG samples declined markedly with the annealing temperatures of 1250-1450 °C. The samples became increasingly orange-yellow in color with the increase of annealing temperature. The potential reasons of discoloration were discussed for the first time. It was attributed to the complex color center [Mg2+F+] formed during the annealing, which was evidenced by optical absorption in the range of 300-500 nm wavelength and the presence of an electron spin resonance (ESR) line at g = 1.9806. The formation mechanism of the complex color center was explained in detail. The complex color center can be eliminated after post-HIP (hot isostatic pressing). And by air annealing and post-HIP, the transmittance of the samples increased from 80.3% to 83.4%.

  7. Additional considerations to the model of musical empathic engagement: Empathy facets, preferences, and openness. Comment on "Music, empathy, and cultural understanding" by E. Clarke et al.

    Science.gov (United States)

    Greenberg, David M.

    2015-12-01

    Recent research has shown that empathy plays an important role in musical experience including perception, preference, and performance [9,11,13,16,17]. Clarke, DeNora, and Vuoskoski's [4] timely review extends this work by establishing a framework for how ;music empathic engagement; can facilitate cultural understanding. In this commentary I raise attention to some additional factors that may be at play in their model.

  8. Thermodynamics of UO2 interaction with carbon in the presence of Al2O3xSiO2, SiC and UC2 additions

    International Nuclear Information System (INIS)

    Khromov, Yu.F.; Svistunov, D.E.; Zhmurov, S.A.

    1985-01-01

    Thermodynamics of carbon interaction with uranium dioxide containing additions of alumosilicates, silicon carbide and uranium dicarbide is studied within the temperature range from 1300 to 1900 K. Uranium dioxide behaviour is analyzed in such compositions under equilibrium and nonequilibrium conditions taking into consideration experimental and calculation data. Equations of reactions are presented and it is shown that silicon and aluminium formation can take place within the range of 1300-1800 K at residual CO pressure lower than 0.133 and 1330 Pa respectivey

  9. Drastic influence of minor Fe or Co additions on the glass forming ability, martensitic transformations and mechanical properties of shape memory Zr-Cu-Al bulk metallic glass composites.

    Science.gov (United States)

    González, Sergio; Pérez, Pablo; Rossinyol, Emma; Suriñach, Santiago; Dolors Baró, Maria; Pellicer, Eva; Sort, Jordi

    2014-06-01

    The microstructure and mechanical properties of Zr 48 Cu 48 -  x Al 4 M x (M ≡ Fe or Co, x  = 0, 0.5, 1 at.%) metallic glass (MG) composites are highly dependent on the amount of Fe or Co added as microalloying elements in the parent Zr 48 Cu 48 Al 4 material. Addition of Fe and Co promotes the transformation from austenite to martensite during the course of nanoindentation or compression experiments, resulting in an enhancement of plasticity. However, the presence of Fe or Co also reduces the glass forming ability, ultimately causing a worsening of the mechanical properties. Owing to the interplay between these two effects, the compressive plasticity for alloys with x  = 0.5 (5.5% in Zr 48 Cu 47.5 Al 4 Co 0.5 and 6.2% in Zr 48 Cu 47.5 Al 4 Fe 0.5 ) is considerably larger than for Zr 48 Cu 48 Al 4 or the alloys with x  = 1. Slight variations in the Young's modulus (around 5-10%) and significant changes in the yield stress (up to 25%) are also observed depending on the composition. The different microstructural factors that have an influence on the mechanical behavior of these composites are investigated in detail: (i) co-existence of amorphous and crystalline phases in the as-cast state, (ii) nature of the crystalline phases (austenite versus martensite content), and (iii) propensity for the austenite to undergo a mechanically-driven martensitic transformation during plastic deformation. Evidence for intragranular nanotwins likely generated in the course of the austenite-martensite transformation is provided by transmission electron microscopy. Our results reveal that fine-tuning of the composition of the Zr-Cu-Al-(Fe,Co) system is crucial in order to optimize the mechanical performance of these bulk MG composites, to make them suitable materials for structural applications.

  10. Abrasive wear resistance and microstructure of Ni-Cr-B-Si hardfacing alloys with additions of Al, Nb, Mo, Fe, Mn and C

    International Nuclear Information System (INIS)

    Berns, H.; Fischer, A.; Theisen, W.

    1987-01-01

    The development of new Ni-base hardfacing alloys for filler wire welding or metal spraying should result in materials with a good resistance against high temperature corrosion and abrasive wear. The first step is to design microstructures, which obtain a satisfactory abrasive wear behaviour at room temperature. Thus, different alloys are melted and scrutinized as to their microstructure and their abrasive wear resistance in laboratory. Compared to commercial Ni-base hardfacing alloys they show a higher volume fraction of coarse hard phases due to the additional, initial solidification of Nb-carbides and Cr-, and Mo-borides. Thus, the abrasive wear resistance is improved. For hard abrasive particles, such as corundum, the Ni-base alloys are more wear resistant than harder Fe-base alloys investigate earlier. This is due to the tougher Ni metal matrix that results in microcracking not to be the most significantly acting wear mechanism

  11. Mechano-hydrothermal preparation of Li-Al-OH layered double hydroxides

    Science.gov (United States)

    Zhang, Fengrong; Hou, Wanguo

    2018-05-01

    A mechano-hydrothermal (MHT) method was used to synthesize Li-Al-OH layered double hydroxides (LDHs) from LiOH·H2O, Al(OH)3 and H2O as starting materials. A two-step synthesis was conducted, that is, Al(OH)3 was milled for 1 h, followed by hydrothermal treatment with LiOH·H2O solution. Effects of the LiOH/Al(OH)3 molar ratio (RLi/Al) and hydrothermal temperature (Tht) on the crystallinity, morphology, and composition of the product were examined. The resulting LDHs were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, Fourier transform infrared, and elemental analyses. The results showed that pre-milling plays a key role in the LDH formation during subsequent hydrothermal treatment. The Li/Al molar ratio of the obtained LDHs keeps constant at 0.5, independent from theRLi/Al (0.5-5.0) in the starting materials. An increase in the Tht (20-80 °C) can enhance the crystallinity and morphology regularity of the products. The so-obtained Li-Al-OH LDHs exhibit high crystallinity and well-dispersity, which may have wider applications than the aggregate ones obtained using conventional mechanochemical and Li+-imbibition methods.

  12. Complexing power of hydro-soluble degradation products from γ-irradiated polyvinylchloride. Influence on Eu(OH)_3(s) solubility and Eu(III) speciation in neutral to alkaline environment

    International Nuclear Information System (INIS)

    Reiller, Pascal E.; Badji, Hawa; Tabarant, Michel; Vercouter, Thomas; Fromentin, Elodie; Ferry, Muriel; Dannoux-Papin, Adeline

    2017-01-01

    The complexing power of hydrosoluble degradation products (HDPs) from an alkaline hydrolysis of a 10 MGy γ-irradiated polyvinylchloride is studied. The complexation of Eu(III), as an analogue of lanthanide and actinide radionuclides at their +III oxidation state for oxygen containing functions, is evidenced both from the increasing of Eu(OH)_3(s) dissolution, and from a complexometric titration by time-resolved luminescence spectroscopy. The dissolution of Eu(OH)_3(s) in a simplified alkaline solution (0.3 M KOH/0.1 M NaOH) increases moderately, but significantly, with the HDPs concentration. The luminescence signal of the supernatant clearly indicates the presence of several complexed Eu(III) species. Performing a complexometric titration of Eu(III) from pH 6 by alkaline HDPs shows the formation of two different species with increasing HDPs' concentration and pH. Operational complexation constants - based on dissolved carbon concentration - are proposed. The analyses of the spectra and luminescence decays seem to confirm the presence of two different species.

  13. Solid-State Synthesis and Structure of the Enigmatic Ammonium Octaborate: (NH4)2[B7O9(OH)5]·3/4B(OH)3·5/4H2O.

    Science.gov (United States)

    Neiner, Doinita; Sevryugina, Yulia V; Schubert, David M

    2016-09-06

    The compound known since the 19th century as ammonium octaborate was structurally characterized revealing the ammonium salt of the ribbon isomer of the heptaborate anion, [B7O9(OH)5](2-), with boric acid and water molecules. Of composition (NH4)2B7.75O12.63·4.88H2O, it approximates the classical ammonium octaborate composition (NH4)2B8O13·6H2O and has the structural formula {(NH4)2[B7O9(OH)5]}4·3B(OH)3·5H2O. It spontaneously forms at room temperature in solid-state mixtures of ammonium tetraborate and ammonium pentaborate. It crystallizes in the monoclinic space group P21/c with a = 11.4137(2) Å, b = 11.8877(2) Å, c = 23.4459(3) Å, β = 90.092(1)°, V = 3181.19(8) Å(3), and Z = 2 and contains well-ordered ammonium cations and [B7O9(OH)5](2-) anions and disordered B(OH)3 and H2O molecules linked by extensive H bonding. Expeditious solid-state formation of the heptaborate anion under ambient conditions has important implications for development of practical syntheses of industrially useful borates.

  14. Cardiac MRI in addition to MR angiography: a longitudinal study in vascular risk patients; Kardiale MRT als Ergaenzung zur MR-Angiografie: Eine longitudinale Studie bei vaskulaeren Risikopatienten

    Energy Technology Data Exchange (ETDEWEB)

    Seeger, A.; Grimm, F.; Fenchel, M.; Kramer, U.; Doering, J.S.; Klumpp, B.; Claussen, C.D.; Miller, S. [Abt. fuer Radiologische Diagnostik, Eberhard-Karls-Univ. Tuebingen (Germany); Scheule, A. [Abt. fuer Herz-, Thorax- und Gefaesschirurgie, Eberhard-Karls-Univ. Tuebingen (Germany); May, A.E. [Abt. fuer Kardiologie, Eberhard-Karls-Univ. Tuebingen (Germany)

    2008-05-15

    Purpose: the aim of the study was to assess the feasibility and additional diagnostic information of cardiac MRI as a supplement to state-of-the-art MR angiography (MRA) in the case of vascular risk patients. Therefore, the prevalence of delayed myocardial enhancement (DE) was determined in patients suffering from peripheral artery disease (PAD) and a clinical follow-up was evaluated after 2 years. Materials and method: 87 consecutive patients (ages 66 {+-} 10 years, 67 males) with symptomatic peripheral arterial occlusive disease (n = 68) or abdominal aortic aneurysm (n = 19) were examined using delayed cardiac enhancement (DE) within the clinical indication of MRA at a 1.5T system. A follow-up examination was carried out two years later (24 months {+-} 4 months) with regards to cardiac events (cardiac death, myocardial infarction or acute coronary syndrome, heart insufficiency, coronary revascularization). Results: in total, 40/87 patients had myocardial infarctions shown in MRI (46%). In 25 patients (29%), the myocardial infarction was already known, while in 15 patients (17%) an occult progressing infarction was diagnosed (38% of the myocardial infarcts). Follow-up data was able to be obtained after 2 years for 82 patients. 15 patients had a major cardiac event during the follow-up period, and 10 (67%) of them already showed DE in the MRI. In the group with occult progressing infarctions, cardiac events occurred in 40% (6/15 patients, cardiac death n = 1, ischemia n = 4, heart insufficiency n = 1, bypass n = 1), in patients with known infarction in 17% (4/23 patients, cardiac death n = 1, ischemia n = 3, bypass n = 2) and in 11% of patients without myocardial scars (5/44 patients, cardiac death n = 1, ischemia n = 2, heart insufficiency n = 2). (orig.)

  15. MF59- and Al(OH3-adjuvanted Staphylococcus aureus (4C-Staph vaccines induce sustained protective humoral and cellular immune responses, with a critical role for effector CD4 T cells at low antibody titers.

    Directory of Open Access Journals (Sweden)

    Elisabetta eMonaci

    2015-09-01

    Full Text Available Staphylococcus aureus (S. aureus is an important opportunistic pathogen that may cause invasive life-threatening infections like sepsis and pneumonia. Due to increasing antibiotic-resistance, the development of an effective vaccine against S. aureus is needed. Although a correlate of protection against staphylococcal diseases is not yet established, several findings suggest that both antibodies and CD4 T cells might contribute to optimal immunity. In this study, we show that adjuvanting a multivalent vaccine (4C-Staph with MF59, an oil-in-water emulsion licensed in human vaccines, further potentiated antigen-specific IgG titers and CD4 T cell responses compared to alum and conferred protection in the peritonitis model of S. aureus infection. Moreover, we showed that MF59- and alum-adjuvanted 4C-Staph vaccines induced persistent antigen-specific humoral and T cell responses, and protected mice from infection up to 4 months after immunization. Furthermore, 4C-Staph formulated with MF59 was used to investigate which immune compartment is involved in vaccine-induced protection. Using CD4 T cell-depleted mice or B cell deficient mice, we demonstrated that both T and B cell responses contributed to 4C-Staph vaccine-mediated protective immunity. However, the role of CD4 T cells seemed more evident in the presence of low antibody responses. This study provides preclinical data further supporting the use of the adjuvanted 4C-Staph vaccines against S. aureus diseases, and provides critical insights on the correlates of protective immunity necessary to combat this pathogen.

  16. Microstructure and Mechanical Properties of Long Ti-6Al-4V Rods Additively Manufactured by Selective Electron Beam Melting Out of a Deep Powder Bed and the Effect of Subsequent Hot Isostatic Pressing

    Science.gov (United States)

    Lu, S. L.; Tang, H. P.; Ning, Y. P.; Liu, N.; StJohn, D. H.; Qian, M.

    2015-09-01

    An array of eight long Ti-6Al-4V rods (diameter: 12 mm; height: 300 mm) have been additively manufactured, vertically and perpendicular to the powder bed, by selective electron beam melting (SEBM). The purpose was to identify and understand the challenges of fabricating Ti-6Al-4V samples or parts from a deep powder bed (more than 200-mm deep) by SEBM and the necessity of applying post heat treatment. The resulting microstructure and mechanical properties of these Ti-6Al-4V rods were characterized along their building ( i.e., axial) direction by dividing each rod into three segments (top, middle, and bottom), both before ( i.e., as-built) and after hot isostatic pressing (HIP). The as-built microstructure of each rod was inhomogeneous; it was coarsest in the top segment, which showed a near equilibrium α- β lamellar structure, and finest in the bottom segment, which featured a non-equilibrium mixed structure. The tensile properties varied along the rod axis, especially the ductility, but all tensile properties met the requirements specified by ASTM F3001-14. HIP increased the relative density from 99.03 pct of the theoretical density (TD) to 99.90 pct TD and homogenized the microstructure thereby leading to highly consistent tensile properties along the rod axis. The temperature of the stainless steel substrate used in the powder bed was monitored. The as-built inhomogeneous microstructure is attributed to the temperature gradient in the deep powder bed. Post heat treatment is thus necessary for Ti-6Al-4V samples or parts manufactured from a deep powder bed by SEBM. This differs from the additive manufacturing of small samples or parts from a shallow powder bed (less than 100-mm deep) by SEBM.

  17. Thermal stability of (AlSi){sub x}(ZrVTi) intermetallic phases in the Al–Si–Cu–Mg cast alloy with additions of Ti, V, and Zr

    Energy Technology Data Exchange (ETDEWEB)

    Shaha, S.K. [Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3 (Canada); Czerwinski, F., E-mail: Frank.Czerwinski@nrcan.gc.ca [CanmetMATERIALS, Natural Resources Canada, 183 Longwood Road South, Hamilton, Ontario L8P 0A5 (Canada); Kasprzak, W. [CanmetMATERIALS, Natural Resources Canada, 183 Longwood Road South, Hamilton, Ontario L8P 0A5 (Canada); Friedman, J.; Chen, D.L. [Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3 (Canada)

    2014-11-10

    Highlights: • Al–Si–Cu–Mg alloy was modified by introducing Zr, V, and Ti. • The chemistry of the phases was identified using SEM/EDX. • The crystal lattice parameters of the phases were characterized using EBSD. • To investigate the phase stability, XRD was performed up to 600 °C. • Thermal analysis was done to find out the possible phase transformation reactions. - Abstract: The Al–Si–Cu–Mg cast alloy was modified with additions of Ti–V–Zr to improve the thermal stability of intermetallics at increased temperatures. A combination of electron microscopy, electron backscatter diffraction, and high temperature X-ray diffraction was explored to identify phases and temperatures of their thermal stability. The micro-additions of transition metals led to formation of several (AlSi){sub x}(TiVZr) phases with D0{sub 22}/D0{sub 23} tetragonal crystal structure and different lattice parameters. While Cu and Mg rich phases along with the eutectic Si dissolved at temperatures from 300 to 500 °C, the (AlSi){sub x}(TiVZr) phases were stable up to 696–705 °C which is the beneficial to enhance the high temperature properties. Findings of this study are useful for selecting temperatures during melting and heat treatment of Al–Si alloys with additions of transition metals.

  18. Effect of boron addition on the microstructures and electrochemical properties of MmNi3.8Co0.4Mn0.6Al0.2 electrode alloys prepared by casting and rapid quenching

    International Nuclear Information System (INIS)

    Zhang Yanghuan; Chen Meiyan; Wang Xinlin; Wang Guoqing; Lin Yufang; Qi Yan

    2004-01-01

    The rapid quenching technology was used in the preparation of the MmNi 3.8 Co 0.4 Mn 0.6 Al 0.2 B x (x=0, 0.1, 0.2, 0.3, 0.4) electrode alloys. The microstructures and electrochemical performances of the as-cast and quenched alloys were analysed and measured. The effects of boron additive on the microstructures and electrochemical properties of as-cast and quenched alloy MmNi 3.8 Co 0.4 Mn 0.6 Al 0.2 were investigated. The experimental results showed that the microstructure of as-cast MmNi 3.8 Co 0.4 Mn 0.6 Al 0.2 B x (x=0, 0.1, 0.2, 0.3, 0.4) alloy is composed of CaCu 5 -type main phase and a small amount of CeCo 4 B-type secondary phase. The abundance of the secondary phase increases with the increase of the boron content x. The secondary phase in the alloys disappears when quenching rate is larger than 22 m/s. The electrochemical measurement showed that the addition of boron slightly modifies the activation performance and dramatically enhances the cycle life of the alloys, whereas it reduces the capacities of the as-cast and quenched alloys. The influence of boron additive on the electrochemical characteristics of the as-quenched alloy is much stronger than that on the as-cast alloy. It is because boron strongly promotes the formation of the amorphous phase in the as-quenched alloy

  19. Nano-structure formation of Fe-Pt perpendicular magnetic recording media co-deposited with MgO, Al2O3 and SiO2 additives

    International Nuclear Information System (INIS)

    Safran, G.; Suzuki, T.; Ouchi, K.; Barna, P.B.; Radnoczi, G.

    2006-01-01

    Perpendicular magnetic recording media samples were prepared by sputter deposition on sapphire with a layer sequence of MgO seed-layer/Cr under-layer/FeSi soft magnetic under-layer/MgO intermediate layer/FePt-oxide recording layer. The effects of MgO, Al 2 O 3 and SiO 2 additives on the morphology and orientation of the FePt layer were investigated by transmission electron microscopy. The samples exhibited (001) orientation of the L1 FePt phase with the mutual orientations of sapphire substrate//MgO(100)[001]//Cr(100)[11-bar0]//FeSi(100)[11-bar0]//MgO(100) [001]//FePt(001)[100]. The morphology of the FePt films varied due to the co-deposited oxides: The FePt layers were continuous and segmented by stacking faults aligned at 54 o to the surface. Films with SiO 2 addition, beside the oriented columnar FePt grains, exhibited a fraction of misoriented crystallites due to random repeated nucleation. Al 2 O 3 addition resulted in a layered structure, i.e. an initial continuous epitaxial FePt layer covered by a secondary layer of FePt-Al 2 O 3 composite. Both components (FePt and MgO) of the MgO-added samples were grown epitaxially on the MgO intermediate layer, so that a nano-composite of intercalated (001) FePt and (001) MgO was formed. The revealed microstructures and formation mechanisms may facilitate the improvement of the structural and magnetic properties of the FePt-oxide composite perpendicular magnetic recording media

  20. Influence of the Sr and Mg Alloying Additions on the Bonding Between Matrix and Reinforcing Particles in the AlSi7Mg/SiC-Cg Hybrid Composite

    Directory of Open Access Journals (Sweden)

    Dolata A. J.

    2016-06-01

    Full Text Available The aim of the work was to perform adequate selection of the phase composition of the composite designated for permanent - mould casting air compressor pistons. The hybrid composites based on AlSi7Mg matrix alloy reinforced with mixture of silicon carbide (SiC and glassy carbon (Cg particles were fabricated by the stir casting method. It has been shown that the proper selection of chemical composition of matrix alloy and its modification by used magnesium and strontium additions gives possibility to obtain both the advantageous casting properties of composite suspensions as well as good bonding between particles reinforcements and matrix.

  1. Improvement of photoluminescence intensity of Ce-doped Y{sub 3}Al{sub 5}O{sub 12} phosphor by Si{sub 3}N{sub 4} addition

    Energy Technology Data Exchange (ETDEWEB)

    Shyu, Jiin-Jyh, E-mail: jjshyu@ttu.edu.tw; Yang, Chia-Wei

    2017-06-01

    Yttrium aluminum garnet (Y{sub 3}Al{sub 5}O{sub 12}, YAG) has been widely used as a host for luminescent ions. The present paper describes the effects of Si{sub 3}N{sub 4} addition on the formation and photoluminescence properties of the Ce-doped YAG yellow phosphors. Phosphor powders with the nominal compositions of Y{sub 2.95}Ce{sub 0.05}Al{sub 5-m}Si{sub m}O{sub 12-m}N{sub m} (m = 0–0.6) were prepared by calcining the mixed raw materials at 1500 °C in nitrogen atmosphere. X-ray diffraction, x-ray photoelectron spectroscopy, scanning electron microscope, and transmission electron microscopy equipped with an energy dispersive x-ray spectrometer were used to characterize the structure of the calcined powders. The photoluminescence properties were measured with fluorescence spectrophotometry. It was found that in the range of m = 0–0.27, single phase YAG solid solution (s.s.) in which the Y, Al, and O sites are partially occupied by Ce, Si, and N ions, respectively. The nitrogen ions do not distribute homogeneously over the YAG lattice. The tendency to bond with nitrogen ion for the cations is (Y, Ce) > Si > Al. With the increase in the Si{sub 3}N{sub 4} content, the increase in both the Ce{sup 3+}/(Ce{sup 3+} + Ce{sup 4+}) ratio and the Ce-N bonds improve the intensity of the photoluminescent emission. At m = 0.27, the emission intensity reaches a maximum which is about 2.5 and 1.6 times of that for the Si{sub 3}N{sub 4}-free composition (m = 0) calcined in air and nitrogen, respectively. When the Si{sub 3}N{sub 4} content (m) is higher than 0.27, the emission intensity decreases due to the existence of residual Si{sub 3}N{sub 4} phase. - Highlights: • Addition of Si{sub 3}N{sub 4} can increase the emission intensity of YAG:Ce up to 2.5 times. • Increase in the Ce{sup 3+}/Ce{sup 4+} ratio and the number of Ce-N bonds improve the emission. • The tendency to bond with nitrogen ion for cations in YAG:Ce is (Y, Ce) > Si > Al. • The incomplete dissolution

  2. Calculated and experimental electron energy-loss spectra of La2O3, La(OH)3, and LaOF nanophases in high permittivity lanthanum-based oxide layers

    Science.gov (United States)

    Calmels, L.; Coulon, P. E.; Schamm-Chardon, S.

    2011-06-01

    Using first principles methods, the O K energy-loss near-edge structure of cubic and hexagonal La2O3, La(OH)3, and LaOF phases have been calculated. These calculations support the identification of nanocrystalline phases evidenced experimentally by electron energy-loss spectroscopy (EELS) performed in a transmission electron microscope. The nanocrystals have been observed in atomic layer deposited La2O3 thin films developed for advanced metal-oxide-semiconductor field effect transistor applications. The presence of the nanophases can be explained by the hygroscopicity and the particular reactivity with fluorine of La2O3. These calculations provide a set of EELS fingerprints which will be useful for local phase identification in La2O3-based materials.

  3. Improvement of the thermoplastic formability of Zr{sub 65}Cu{sub 17.5}Ni{sub 10}Al{sub 7.5} bulk metallic glass by minor addition of Erbium

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Q. [Shenzhen Key Laboratory of Special Functional Materials, College of Materials Science and Engineering, Shenzhen 518060 (China); Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); Zeng, X.R., E-mail: zengxier@szu.edu.cn [Shenzhen Key Laboratory of Special Functional Materials, College of Materials Science and Engineering, Shenzhen 518060 (China); Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); JANUS Precision Components Co., LTD., Dongguan 523000 (China); Fu, M.W., E-mail: mmmwfu@polyu.edu.hk [Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China); Chen, S.S. [Shenzhen Key Laboratory of Special Functional Materials, College of Materials Science and Engineering, Shenzhen 518060 (China); Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); Jiang, J. [Institute of Applied Physics, Jiangxi Academy of Sciences, Nanchang 330029 (China)

    2016-12-01

    The softness of Zr{sub 65}Cu{sub 17.5}Ni{sub 10}Al{sub 7.5} bulk metallic glass (BMG) in the super-cooled liquid range (SCLR) is obviously improved by minor addition of 2% Er, which makes (Zr{sub 65}Cu{sub 17.5}Ni{sub 10}Al{sub 7.5}){sub 98}Er{sub 2} (Zr65Er2) to be a very formable Be-free Zr-based BMG. It is found the lower glass transition temperature of Zr65Er2 has an important contribution to the improvement of formability, which is contrary to the general understanding that the larger fragility and wider super-cooled liquid region (SCLR) are the major reasons for better thermoplastic formability. This finding is well explained by using the linear simplification of the SCLR in Angell plot. Zr65Er2 also has lower crystallization temperature and melting temperature, which is believed to be related to the formation of short-range ordering with lower transition energy rather than the composition shift to near eutectic. The above results help understand the effect of minor addition of rare-earth to the formability of Zr-based bulk metallic glasses.

  4. Hydrogen generation from Al-NiCl2/NaBH4 mixture affected by lanthanum metal.

    Science.gov (United States)

    Sun, Wen Qiang; Fan, Mei-Qiang; Fei, Yong; Pan, Hua; Wang, Liang Liang; Yao, Jun

    2012-01-01

    The effect of La on Al/NaBH(4) hydrolysis was elaborated in the present paper. Hydrogen generation amount increases but hydrogen generation rate decreases with La content increasing. There is an optimized composition that Al-15 wt% La-5 wt% NiCl(2)/NaBH(4) mixture (Al-15 wt% La-5 wt% NiCl(2)/NaBH(4) weight ratio, 1 : 3) has 126 mL g(-1 )min(-1) maximum hydrogen generation rate and 1764 mL g(-1) hydrogen generation amount within 60 min. The efficiency is 88%. Combined with NiCl(2), La has great effect on NaBH(4) hydrolysis but has little effect on Al hydrolysis. Increasing La content is helpful to decrease the particle size of Al-La-NiCl(2) in the milling process, which induces that the hydrolysis byproduct Ni(2)B is highly distributed into Al(OH)(3) and the catalytic reactivity of Ni(2)B/Al(OH)(3) is increased therefore. But hydrolysis byproduct La(OH)(3) deposits on Al surface and leads to some side effect. The Al-La-NiCl(2)/NaBH(4) mixture has good stability in low temperature and its hydrolytic performance can be improved with increasing global temperature. Therefore, the mixture has good safety and can be applied as on board hydrogen generation material.

  5. Solid-state 27Al and 29Si NMR characterization of hydrates formed in calcium aluminate-silica fume mixtures

    International Nuclear Information System (INIS)

    Pena, P.; Rivas Mercury, J.M.; Aza, A.H. de; Turrillas, X.; Sobrados, I.; Sanz, J.

    2008-01-01

    Partially deuterated Ca 3 Al 2 (SiO 4 ) y (OH) 12-4y -Al(OH) 3 mixtures, prepared by hydration of Ca 3 Al 2 O 6 (C 3 A), Ca 12 Al 14 O 33 (C 12 A 7 ) and CaAl 2 O 4 (CA) phases in the presence of silica fume, have been characterized by 29 Si and 27 Al magic-angle spinning-nuclear magnetic resonance (MAS-NMR) spectroscopies. NMR spectroscopy was used to characterize anhydrous and fully hydrated samples. In hydrated compounds, Ca 3 Al 2 (OH) 12 and Al(OH) 3 phases were detected. From the quantitative analysis of 27 Al NMR signals, the Al(OH) 3 /Ca 3 Al 2 (OH) 12 ratio was deduced. The incorporation of Si into the katoite structure, Ca 3 Al 2 (SiO 4 ) 3-x (OH) 4x , was followed by 27 Al and 29 Si NMR spectroscopies. Si/OH ratios were determined from the quantitative analysis of 27 Al MAS-NMR components associated with Al(OH) 6 and Al(OSi)(OH) 5 environments. The 29 Si NMR spectroscopy was also used to quantify the unreacted silica and amorphous calcium aluminosilicate hydrates formed, C-S-H and C-A-S-H for short. From 29 Si NMR spectra, the amount of Si incorporated into different phases was estimated. Si and Al concentrations, deduced by NMR, transmission electron microscopy, energy dispersive spectrometry, and Rietveld analysis of both X-ray and neutron data, indicate that only a part of available Si is incorporated in katoite structures. - Graphical abstract: Transmission electron micrograph of CaAl 2 O 4 -microsilica mixture hydrated at 90 deg. C for 31 days showing a cubic Ca 3 Al 2.0±0.2 (SiO 4 ) 0.9±0.2 (OH) 1.8 crystal surrounded by unreacted amorphous silica spheres

  6. Additively manufactured 3D porous Ti-6Al-4V constructs mimic trabecular bone structure and regulate osteoblast proliferation, differentiation and local factor production in a porosity and surface roughness dependent manner

    International Nuclear Information System (INIS)

    Cheng, Alice; Boyan, Barbara D; Humayun, Aiza; Cohen, David J; Schwartz, Zvi

    2014-01-01

    Additive manufacturing by laser sintering is able to produce high resolution metal constructs for orthopedic and dental implants. In this study, we used a human trabecular bone template to design and manufacture Ti-6Al-4V constructs with varying porosity via laser sintering. Characterization of constructs revealed interconnected porosities ranging from 15–70% with compressive moduli of 2579–3693 MPa. These constructs with macro porosity were further surface-treated to create a desirable multi-scale micro-/nano-roughness, which has been shown to enhance the osseointegration process. Osteoblasts (MG63 cells) exhibited high viability when grown on the constructs. Proliferation (DNA) and alkaline phosphatase specific activity, an early differentiation marker, decreased as porosity increased, while osteocalcin, a late differentiation marker, as well as osteoprotegerin, vascular endothelial growth factor and bone morphogenetic proteins 2 and 4 increased with increasing porosity. Three-dimensional (3D) constructs with the highest porosity and surface modification supported the greatest osteoblast differentiation and local factor production. These results indicate that additively manufactured 3D porous constructs mimicking human trabecular bone and produced with additional surface treatment can be customized for increased osteoblast response. Increased factors for osteoblast maturation and differentiation on high porosity constructs suggest the enhanced performance of these surfaces for increasing osseointegration in vivo. (paper)

  7. Additively manufactured 3D porous Ti-6Al-4V constructs mimic trabecular bone structure and regulate osteoblast proliferation, differentiation and local factor production in a porosity and surface roughness dependent manner.

    Science.gov (United States)

    Cheng, Alice; Humayun, Aiza; Cohen, David J; Boyan, Barbara D; Schwartz, Zvi

    2014-10-07

    Additive manufacturing by laser sintering is able to produce high resolution metal constructs for orthopedic and dental implants. In this study, we used a human trabecular bone template to design and manufacture Ti-6Al-4V constructs with varying porosity via laser sintering. Characterization of constructs revealed interconnected porosities ranging from 15-70% with compressive moduli of 2579-3693 MPa. These constructs with macro porosity were further surface-treated to create a desirable multi-scale micro-/nano-roughness, which has been shown to enhance the osseointegration process. Osteoblasts (MG63 cells) exhibited high viability when grown on the constructs. Proliferation (DNA) and alkaline phosphatase specific activity, an early differentiation marker, decreased as porosity increased, while osteocalcin, a late differentiation marker, as well as osteoprotegerin, vascular endothelial growth factor and bone morphogenetic proteins 2 and 4 increased with increasing porosity. Three-dimensional (3D) constructs with the highest porosity and surface modification supported the greatest osteoblast differentiation and local factor production. These results indicate that additively manufactured 3D porous constructs mimicking human trabecular bone and produced with additional surface treatment can be customized for increased osteoblast response. Increased factors for osteoblast maturation and differentiation on high porosity constructs suggest the enhanced performance of these surfaces for increasing osseointegration in vivo.

  8. The effect of the addition of the elements Ni, Zn and Co in a composite AlTiO2 obtained by high-energy milling and sintering process

    International Nuclear Information System (INIS)

    Carvalho, C.O. de; Coelho, R.E.; Conrado, L.C.; Nascimento, C.S.; Teixeira, C.A.; Mendonca, E.S.

    2016-01-01

    The present work use aluminum scrap with addition of TiO 2 , Ni, Zn or Co to preparation and characterization of nanocomposites. The aluminum were cut and subjected to high energy milling for 2 hours at 1200rpm. The obtained powder was added to TiO 2 , Ni, Zn or Co in a nominal composition 97Al-2TiO 2 -1X (X = Ni, Zn or Co) (weight %) and again, the mixture was subjected to milling for 1 hour at 1000rpm. Grinding powders were hot pressed in the closed die and then removed; the compressed were sintered at 950°C in a tubular furnace N 2 passing atmosphere. The samples obtained were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and X-ray Diffraction (XRD). The results of SEM images showed a very refined microstructure and an aluminum matrix without porosity. (author)

  9. Oxidation behaviors of the TiNi/Ti_2Ni matrix composite coatings with different contents of TaC addition fabricated on Ti6Al4V by laser cladding

    International Nuclear Information System (INIS)

    Lv, Y.H.; Li, J.; Tao, Y.F.; Hu, L.F.

    2016-01-01

    The TiNi/Ti_2Ni matrix composite coatings were fabricated on Ti6Al4V by laser cladding the mixtures of NiCrBSi and different contents of TaC (0 wt%, 5 wt%, 15 wt%, 30 wt% and 40 wt%). Scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray diffractometry (XRD) were used to examine the microstructures of the coatings. Oxidation behaviors of these coatings were also investigated at 800 °C for 50 h in air. The results showed that the coating without TaC addition was mainly composed of TiNi/Ti_2Ni as the matrix and TiC/TiB_2/TiB as the reinforcement. TaC was dissolved completely and precipitated again during laser cladding. Ta and C from the added TaC mainly existed as the solute atoms in the solid solutions of TiC, TiB_2 and TiB in the coatings with TaC addition. The addition of TaC refined the microstructures of the coatings. In the oxidation test, the oxidation process was divided into the violent oxidation stage and the slow oxidation stage. The oxidation rates of the substrate and the coatings with different contents of TaC (0, 5, 15, 30, 40 wt%) were 0.644, 0.287, 0.173, 0.161, 0.223 and 0.072 mg cm"−"2 h"−"1 in the first stage, 0.884, 0.215, 0.136, 0.126, 0.108 and 0.040 mg"2 cm"−"4 h"−"1 in the second stage, respectively. The weight gain of these samples were 6.70, 3.30, 2.86, 2.64, 2.41 and 1.69 mg cm"−"2, respectively after the whole oxidation test. The oxidation film formed on the surface of the coating without TaC addition mainly consisted of TiO_2, Al_2O_3, and a small amount of NiO, Cr_2O_3 and SiO_2. Moreover, Ta_2O_5 was also formed on the surfaces of these coatings with different contents of TaC. The oxides formed during the oxidation test were supposed to be responsible for the improvement in oxidation resistance of these coatings. - Highlights: • The composite coatings with TaC addition were fabricated on Ti6Al4V by laser cladding. • Effect of TaC addition on microstructural evolution of the coatings was

  10. Oxidation behaviors of the TiNi/Ti{sub 2}Ni matrix composite coatings with different contents of TaC addition fabricated on Ti6Al4V by laser cladding

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Y.H.; Li, J., E-mail: jacob_lijun@sina.com; Tao, Y.F.; Hu, L.F.

    2016-09-15

    The TiNi/Ti{sub 2}Ni matrix composite coatings were fabricated on Ti6Al4V by laser cladding the mixtures of NiCrBSi and different contents of TaC (0 wt%, 5 wt%, 15 wt%, 30 wt% and 40 wt%). Scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray diffractometry (XRD) were used to examine the microstructures of the coatings. Oxidation behaviors of these coatings were also investigated at 800 °C for 50 h in air. The results showed that the coating without TaC addition was mainly composed of TiNi/Ti{sub 2}Ni as the matrix and TiC/TiB{sub 2}/TiB as the reinforcement. TaC was dissolved completely and precipitated again during laser cladding. Ta and C from the added TaC mainly existed as the solute atoms in the solid solutions of TiC, TiB{sub 2} and TiB in the coatings with TaC addition. The addition of TaC refined the microstructures of the coatings. In the oxidation test, the oxidation process was divided into the violent oxidation stage and the slow oxidation stage. The oxidation rates of the substrate and the coatings with different contents of TaC (0, 5, 15, 30, 40 wt%) were 0.644, 0.287, 0.173, 0.161, 0.223 and 0.072 mg cm{sup −2} h{sup −1} in the first stage, 0.884, 0.215, 0.136, 0.126, 0.108 and 0.040 mg{sup 2} cm{sup −4} h{sup −1} in the second stage, respectively. The weight gain of these samples were 6.70, 3.30, 2.86, 2.64, 2.41 and 1.69 mg cm{sup −2}, respectively after the whole oxidation test. The oxidation film formed on the surface of the coating without TaC addition mainly consisted of TiO{sub 2}, Al{sub 2}O{sub 3}, and a small amount of NiO, Cr{sub 2}O{sub 3} and SiO{sub 2}. Moreover, Ta{sub 2}O{sub 5} was also formed on the surfaces of these coatings with different contents of TaC. The oxides formed during the oxidation test were supposed to be responsible for the improvement in oxidation resistance of these coatings. - Highlights: • The composite coatings with TaC addition were fabricated on Ti6Al4V by laser

  11. Sintering of SiC ceramics, via liquid phase, with Al{sub 2}O{sub 3}-Yb{sub 2}O{sub 3} additives; Sinterizacao de ceramicas de SiC, via fase liquida, com aditivos de Al{sub 2}O{sub 3}-Yb{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Atilio, I.; Oliveira, M.R.; Garcia, G.C.R.; Ribeiro, S., E-mail: isabelaatilio@hotmail.com [Universidade de Sao Paulo (USP/EEL), Lorena, SP (Brazil). Escola de Engenharia. Dept. de Engenharia de Materiais

    2012-07-01

    The objective of this work was to study the sintering of SiC, through liquid phase, using the additive system Al{sub 2}O{sub 3} and Yb{sub 2}O{sub 3} for the first time. The samples were sintered at temperatures of 1900, 1950 and 2000 deg C for 60 minutes. The melting point of the system was determined according to DIN 51730. It has been found the ability of wetting of SiC in the system. The densification results were: 86,36% at 1900 deg C, 88,25% at 1950 deg C and 82,09% at 2000 deg C. The average linear shrinkage was approximately 17%. There was a conversion of β-SiC in α-SiC at all temperatures and sintering phase formation Yb{sub 3}Al{sub 5}O{sub 12}. The melting temperature was 1850 deg C for de system, consistent with the value in the phase diagram, and the wetting angle of 20 deg. The system (Yb{sub 2}O{sub 3}-Al{sub 2}O{sub 3}) is promising to make liquid phase sintering of SiC, for presenting a good result of wettability. (author)

  12. Influence of Y2O3 Addition on Crystallization, Thermal, Mechanical, and Electrical Properties of BaO-Al2O3-B2O3-SiO2 Glass-Ceramic for Ceramic Ball Grid Array Package

    Science.gov (United States)

    Li, Bo; Li, Wei; Zheng, Jingguo

    2018-01-01

    Y2O3 addition has a significant influence on the crystallization, thermal, mechanical, and electrical properties of BaO -Al2O3 -B2O3 -SiO2 (BABS) glass-ceramics. Semi-quantitative calculation based on x-ray diffraction demonstrated that with increasing Y2O3 content, both the crystallinity and the phase content of cristobalite gradually decreased. It is effective for the additive Y2O3 to inhibit the formation of cristobalite phase with a large coefficient of thermal expansion value. The flexural strength and the Young's modulus, thus, are remarkably increased from 140 MPa to 200 MPa and 56.5 GPa to 63.7 GPa, respectively. Also, the sintering kinetics of BABS glass-ceramics with various Y2O3 were investigated using the isothermal sintering shrinkage curve at different sintering temperatures. The sintering activation energy Q sharply decreased from 99.8 kJ/mol to 81.5 kJ/mol when 0.2% Y2O3 was added, which indicated that a small amount of Y2O3 could effectively promote the sintering procedure of BABS glass-ceramics.

  13. Antimicrobial activity study of a μ3-oxo bridged [Fe3O(PhCO2)6(MeOH)3](NO3)(MeOH)2] cluster

    Science.gov (United States)

    Pathak, Sayantan; Jana, Barun; Mandal, Manab; Mandal, Vivekananda; Ghorai, Tanmay K.

    2017-11-01

    Synthesis, characterization and antimicrobial activity of a tri-nuclear μ3-Oxobridged Fe(III) cluster [Fe3O(PhCO2)6(MeOH)3](NO3)(MeOH)2(1) is reported. Cluster 1 is synthesized in a single pot reaction among Fe(NO3)3·9H2O, C6H5COOH, NaN3 (1:4:1) in MeOH. Single crystal X-ray diffraction studies of the isolated crystals show that it is μ3-Oxo bridged trimeric assembly of three Fe atoms via bridging benzoate anions. Furthermore, BVS calculations show that all three Fe atoms in complex 1 are in +3 oxidation state and are surrounded by benzoate anions and methanol in octahedral environment. The oxidation state of iron is also confirmed from the cyclic voltamogram. FT-IR spectroscopy and CHN analysis of the isolated crystals further supports the functional group attached to the periphery of the complex. The nanomolecular size of complex 1 is 1.29 nm. The antimicrobial efficiency studies of the complex 1 show significant inhibition of the growth of the organisms, viz. B. cereus MTCC 1272, S. epidermidis MTCC 3086 and S. typhimurium MTCC 98 and produced 23 ± 1.93 mm, 16 ± 1.77 mm and 12 ± 2.42 mm inhibition zones respectively. However, it shows zero inhibition to the strain of E. coli MTCC 723.

  14. Evaluation of alkaline dissolution of Al 6061 and Al 1050 for the production of Mo-99 from LEU targets

    International Nuclear Information System (INIS)

    Mindrisz, Ana C.; Camilo, Ruth L.; Araujo, Izilda C.; Forbicini, Christina A.L.G. de O.

    2013-01-01

    Since 2008, due to the global crisis in the production of radioisotope 99 Mo, which product of decay, 99m Tc, is the tracer element most often used in nuclear medicine and accounts for about 80% of all diagnostic procedures in vivo. Studies on the alkaline dissolution to obtain 9 9M o from irradiated UAl x -Al LEU targets are under development. Processing time should be minimized, considering the short half-life of 99 Mo and 99m Tc, about 66 h and 6 h, respectively. This makes dissolution time a significant factor in the development of the process. This paper presents the results of alkaline dissolution of 'scraps' of Al 6061 and 1050, used to simulate the dissolution process of UAl x -Al targets. Dissolution time and gas releasing were evaluated using the following alkaline solutions: a) NaOH 3 mol.L -1 and NaNO 3 2 mol.L -1 , b) NaOH 3 mol.L -1 and NaNO 3 4 mol.L -1 . The initial temperature of dissolution was 85 deg C in all cases. Al 6061 showed values of dissolution time greater than that for Al 1050, 25% for NaNO 3 2 mol.L -1 and 104.55% for NaNO 3 4 mol.L -1 . The dissolution with NaNO 3 2 mol.L -1 showed that the gas releasing for Al 6061 was 2.7% greater than for Al 1050. However Al 1050 showed that gas releasing 9.92% greater than for Al 6061 during the dissolution with NaNO 3 4 mol.L -1 . The decision about what type of alloy has to be used, Al 1050 or Al 6061, it will be upto the group that will manufacture the targets for the RMB. (author)

  15. Sintering of Si C by hot-pressing with addition of Al{sub 2}O{sub 3} and concentrate of rare earths; Sinterizacao por prensagem a quente com SiC com adicao de Al{sub 2}O{sub 3} e concentrado de terras raras

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, M.K.; Silva, C.R.M. [Centro Tecnico Aeroespacial (CTA-IAE), Sao Jose dos Campos, SP (Brazil). Inst. de Atividades Espaciais]. E-mail: miriamk@iae.cta.br; Nono, M.C.A.; Vieira, R.A. [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil)

    2004-07-01

    Silicon carbide (SiC) has essentially covalent bonds ({approx}88%). The high covalency bond is responsible for the good mechanical properties, although it induces a low self diffusion coefficient, making densification more difficult. For a successful densification is necessary to apply pressure on the samples, and/or the addition of sintering additives, which improves the densification. In this SiC samples with alumina (Al2O3) and concentrate of rare earth (CRE) addition were sintered by hot pressing in argon atmospheric at 20 MPa of pressure, heating rate of 20 deg C/min up to 1800 deg C and a dwell time of 1 h. Initially the CRE was calcined at 1000 deg C during 1 h. After that, three mixtures were prepared with distinct concentrations in high energy mill and the samples were sintered. The aim of this work is to improve SiC densification by the liquid phase formation during sintering owing to the additives reactions between itself. The pressure intensify the driving force for densification, taking the liquid phase to drain easier through the grain boundaries, making possible best accommodation and rearrangement of the grains. The application of the pressure on the samples during sintering contributes to improve densification and becomes possible sintering in lower temperature than conventional one. The phases of the sintered samples were analyzed by X-ray diffraction and the morphology were verified by scanning electron microscopy. (author)

  16. Effects of superfine refractory carbide additives on microstructure and mechanical properties of TiB2–TiC+Al2O3 composite ceramic cutting tool materials

    International Nuclear Information System (INIS)

    Zou, Bin; Ji, Wenbin; Huang, Chuanzhen; Wang, Jun; Li, Shasha; Xu, Kaitao

    2014-01-01

    Highlights: • The superfine carbides determined the mechanical properties of composites. • Superfine HfC or TaC caused some oxide impurities in composites. • Superfine VC or NbC refined and homogenized the microstructure. • Failure of composites containing HfC or TaC was produced by larger grains. • Composite containing VC exhibited more bridging and transcrystalline failure. -- Abstract: A study to increase the mechanical properties of TiB 2 –TiC+Al 2 O 3 composite ceramic cutting tool material by using superfine refractory carbide additives is presented. Four superfine refractory carbides are considered to investigate their effects on the phase composition, element distribution, grain size, fracture surface, crack propagation of the metal ceramic. The physicochemical properties of superfine carbides, such as chemical activities and atom radius, were found to have the significant effects on the microstructure and mechanical properties of the metal ceramic. Hafnium carbide (HfC) and Tantalum carbide (TaC) reduced the mechanical properties of the metal ceramic because of their poor solubility with the Ni binder phase and the formation of oxides. The mechanical properties of the metal ceramic were increased by the addition of superfine niobium carbide (NbC) and vanadium carbide (VC), and their optimum values were a flexural strength of 1100 ± 62 MPa, fracture toughness of 8.5 ± 0.8 MPa.m1/2 and hardness of 21.53 ± 0.36 GPa, respectively, when 3.2 wt% superfine VC was used

  17. ALS Association

    Science.gov (United States)

    ... toward a world without ALS! Walk to Defeat ALS® Walk to Defeat ALS® draws people of all ... We need your help. I Will Advocate National ALS Registry The National ALS Registry is a congressionally ...

  18. Familial ALS

    Science.gov (United States)

    Boylan, Kevin

    2015-01-01

    Synopsis Genes linked to ALS susceptibility are being identified at an increasing rate owing to advances in molecular genetic technology. Genetic mechanisms in ALS pathogenesis appear to exert major effects in ~10% of patients, but genetic factors at some level may be important components of disease risk in most ALS patients. Identification of gene variants associated with ALS has informed concepts of the pathogenesis of ALS, aided the identification of therapeutic targets, facilitated research to develop new ALS biomarkers, and supported the establishment of clinical diagnostic tests for ALS-linked genes. Translation of this knowledge to ALS therapy development is ongoing. PMID:26515623

  19. Effect of Y{sub 2}O{sub 3} addition to Rh/Al{sub 2}O{sub 3} catalysts on the autothermal reforming of methane; Efeito da adicao de Y{sub 2}O{sub 3} a catalisadores de Rh/Al{sub 2}O{sub 3} na reforma autotermica do metano

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Vanessa Monteiro; Cardoso, Gabriel Alexandre Lima; Coutinho, Ana Carla da S. Lomba S.; Passos, Fabio Barboza [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Dept. de Engenharia Quimica e de Petroleo. Lab. de Reatores, Cinetica e Catalise (RECAT)]. E-mail: vanessafisqui@yahoo.com.br

    2008-07-01

    In this work, the effect of the addition of Y{sub 2}O{sub 3} (with 2%, 5% and 10% weight content) on Rh/{alpha}-Al{sub 2}O{sub 3} catalysts in the autothermal reforming reaction of methane to the production of hydrogen for fuel cells was investigated. The catalysts were characterized by the following techniques: N{sub 2} adsorption, H{sub 2} chemisorption, X-ray diffraction (XRD) and cyclohexane dehydrogenation reaction. The catalysts were also evaluated in the reaction of autothermal reforming. The catalyst with higher Y{sub 2}O{sub 3} content showed the best results both in the cyclohexane dehydrogenation rate and in the conversion of methane. (author)

  20. The effect of the addition of the elements Ni, Zn and Co in a composite AlTiO{sub 2} obtained by high-energy milling and sintering process; Efeito da adicao dos elementos Ni, Zn ou Co no composito AlTiO{sub 2} obtido por moagem de alta energia e sinterizacao

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, C.O. de; Coelho, R.E.; Conrado, L.C.; Nascimento, C.S.; Teixeira, C.A.; Mendonca, E.S., E-mail: cristiane.olv.carvalho@hotmail.com [Instituto Federal de Educacao, Ciencia e Tecnologia da Bahia (IFBA), BA (Brazil)

    2016-07-01

    The present work use aluminum scrap with addition of TiO{sub 2}, Ni, Zn or Co to preparation and characterization of nanocomposites. The aluminum were cut and subjected to high energy milling for 2 hours at 1200rpm. The obtained powder was added to TiO{sub 2}, Ni, Zn or Co in a nominal composition 97Al-2TiO{sub 2}-1X (X = Ni, Zn or Co) (weight %) and again, the mixture was subjected to milling for 1 hour at 1000rpm. Grinding powders were hot pressed in the closed die and then removed; the compressed were sintered at 950°C in a tubular furnace N{sub 2} passing atmosphere. The samples obtained were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and X-ray Diffraction (XRD). The results of SEM images showed a very refined microstructure and an aluminum matrix without porosity. (author)

  1. Hydrogen generation by aluminum corrosion in aqueous alkaline solutions of inorganic promoters: The AlHidrox process

    International Nuclear Information System (INIS)

    Macanas, Jorge; Soler, Lluis; Candela, Angelica Maria; Munoz, Maria; Casado, Juan

    2011-01-01

    The research of alternative processes to obtain clean fuels has become a main issue because of the concerns related to the current energy system, both from economical and environmental points of view. Hydrogen storage and production methods are being investigated for stationary and portable applications. Up to now, a significant part of H 2 production on demand was thought to be fulfilled by using chemical hydrides, but recent studies have proved the limitations of this approach. Conversely, H 2 production based in the corrosion of light metals in water solutions is an interesting alternative. Among all of them, Al is probably the most adequate metal for energetic purposes due to its high electron density and oxidation potential. But concerning H 2 production from Al corrosion in water, a major issue remains unsolved: metal passivation due to the formation of Al(OH) 3 inhibits H 2 evolution. In this work we show the last results obtained for the generation of H 2 from water using Al powder using diverse alkaline solutions. It is confirmed that corrosion is not affected solely by the solution pH but also by the nature of the ionic species found in the aqueous medium. Moreover, we describe the AlHidrox process, which minimizes Al passivation under mild conditions by the addition of different inorganic salts as corrosion promoters, allowing 100% yields and flow rates up to 2.9 L/min per gram of Al. The feasibility of the process has been regarded in terms of stability (by conducting several successive runs) and self-initiation without an external heating. -- Highlights: → The AlHidrox process minimizes Al passivation by the addition of inorganic salts. → Al corrosion to produce H 2 greatly depends on the nature of the dissolved species. → The maximum flow achieved was 2.9 dm 3 H 2 min -1 .per gram of Al using Fe 2 (SO 4 ) 3 . → We found conditions to start up H 2 generation without external energy input.

  2. Comparative analysis of Nb and Ti addition in the Cu-11,8%wt.Al-0,5%wt.Be e Cu-11,8%wt.Al-3,0%wt.Ni shape memory alloy; Analise comparativa da adicao de NB e TI nas ligas Cu-11,8Al-0,5Be e Cu-11,8Al-3,0Ni passiveis do efeito memoria de forma

    Energy Technology Data Exchange (ETDEWEB)

    Silva Junior, M.Q. da; Oliveira, G.D. de, E-mail: manoel.quirino@ufersa.edu.br [Universidade Federal Rural do Semi-Arido (UFERSA), Mossoro, RN (Brazil)

    2014-07-01

    The system of the Cu-Al alloys shape memory alloy have been the subject of many studies due to a wide range of possible applications and relatively low cost, and the chemical composition of the main factors that determine the properties of these properties. This work analyzed the influence of Nb and Ti elements in Cu-11,8Al-0,5Be and Cu-11,8Al-3,0Ni alloy. The alloys are obtained by melting and passed through homogenizing heat treatment followed by water quenching at 30°C. The samples were characterized by Microscopy Optical, X-ray Diffraction and Microhardness testing. The alloys showed fine precipitates of second phase homogeneously distributed in the matrix that provides improvement in the properties of these alloys. (author)

  3. Additive manufacturing.

    Science.gov (United States)

    Mumith, A; Thomas, M; Shah, Z; Coathup, M; Blunn, G

    2018-04-01

    Increasing innovation in rapid prototyping (RP) and additive manufacturing (AM), also known as 3D printing, is bringing about major changes in translational surgical research. This review describes the current position in the use of additive manufacturing in orthopaedic surgery. Cite this article: Bone Joint J 2018;100-B:455-60.

  4. Food additives

    Science.gov (United States)

    ... GO About MedlinePlus Site Map FAQs Customer Support Health Topics Drugs & Supplements Videos & Tools Español You Are Here: Home → Medical Encyclopedia → Food additives URL of this page: //medlineplus.gov/ency/article/ ...

  5. A comparison of porosity analysis using 2D stereology estimates and 3D serial sectioning for additively manufactured Ti 6Al 2Sn 4Zr 2Mo alloy; Vergleich der Porositaetsanalyse einer Ti 6Al 2Sn 4Zr 2Mo-Legierung aus additiver Fertigung mittels stereologischer Schaetzungen (2D) und mit Serienschnitten (3D)

    Energy Technology Data Exchange (ETDEWEB)

    Ganti, Satya R.; Velez, Michael A.; Geier, Brian A.; Hayes, Brian J.; Turner, Bryan J.; Jenkins, Elizabeth J. [UES Inc., Dayton, OH (United States)

    2017-02-15

    Porosity is a typical defect in additively manufactured (AM) parts. Such defects limit the properties and performance of AM parts, and therefore need to be characterized accurately. Current methods for characterization of defects and microstructure rely on classical stereological methods that extrapolate information from two dimensional images. The automation of serial sectioning provides an opportunity to precisely and accurately quantify porosity in three dimensions in materials. In this work, we analyzed the porosity of an additively manufactured Ti 6Al 2Sn 4Zr 2Mo sample using Robo-Met.3D {sup registered}, an automated serial sectioning system. Image processing for three dimensional reconstruction of the serial-sectioned two dimensional images was performed using open source image analysis software (Fiji/ImageJ, Dream.3D, Paraview). The results from this 3D serial sectioning analysis were then compared to classical 2D stereological methods (Saltykov stereological theory). We found that for this dataset, the classical 2D methods underestimated the porosity size and distributions of the larger pores; a critical attribute to fatigue behavior of the AM part. The results suggest that acquiring experimental data with equipment such as Robo-Met.3D {sup registered} to measure the number and size of particles such as pores in a volume irrespective of knowing their shape is a better choice.

  6. Mechanochemical synthesis of Cu-Al and methyl orange intercalated Cu-Al layered double hydroxides

    International Nuclear Information System (INIS)

    Qu, Jun; He, Xiaoman; Chen, Min; Hu, Huimin; Zhang, Qiwu; Liu, Xinzhong

    2017-01-01

    In this study, a mechanochemical route to synthesize a Cu-Al layered double hydroxide (LDH) and a methyl orange (MO) intercalated one (MO-LDH) was introduced, in which basic cupric carbonate (Cu_2(OH)_2CO_3) and aluminum hydroxide (Al(OH)_3) with Cu/Al molar ratio at 2/1 was first dry ground for 2 h and then agitated in water or methyl orange solution for another 4 h to obtain the LDH and MO-LDH products without any heating operation. The prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermogravimetry (TG), Differential scanning calorimetry (DSC) and Scanning electron microscopy (SEM). The products showed high crystallinity phase of Cu-Al and MO intercalated Cu-Al LDH with no evident impurities, proving that the craft introduced here was facile and effective. The new idea can be applied in other fields to produce organic-inorganic composites. - Highlights: • A facile mechanochemical route to synthesize Cu-Al and MO intercalated Cu-Al LDH. • The products possesses high crystalline of LDH phase with no impure phases. • The dry milling process induces the element substitution between the raw materials. • The agitation operation helps the grain growth of LDH.

  7. Determination of the constants of the solubility product of Ln(OH)3 and the effect of the chloride ions on the lanthanum hydrolysis, praseodymium and lutetium in aqueous solutions of ion force 2 Molar

    International Nuclear Information System (INIS)

    Lopez G, H.D.

    2005-01-01

    The behavior of lanthanum (III), praseodymium (III), and lutetium (III) was studied in 2 M NaClO 4 (aq) and 2 M NaCl (aq) at 303 K and free -CO 2 conditions. Solubility diagrams (p Ln(aq)-pC H ) were obtained by means of a radiochemical method. The pC H borderlines of saturation and unsaturation zones of the solutions and solubility product constants for Ln(OH) 3 were determined from these diagrams. The fitting of the solubility equation to the experimental values of p Ln(aq)-pC H diagrams allowed the calculation of the first hydrolysis and solubility product constants. Independently, the stability constants for the first species of hydrolysis were determined by means of pH titrations, the data were treated with the program SUPERQUAD and fitted to the mean ligand number equation. The stability constants for the species LnCl 2+ were as well calculated in 2M ionic strength and 303 K from the hydrolysis constant values obtained in both perchlorate and chloride media. The values obtained for La, Pr and Lu were: logK ps : 21.11 ± 0.09, 19.81 ± 0.11 and 18.10 ± 0.13 in 2M NaClO 4 ; logK ps : 22.22 ± 0.09, 21.45 ± 0.14 and 18.52 ± 0.29 in 2M NaCl; log β 1 : - 8.64 ± 0.02, - 8.37 ± 0.01 and - 7.95 ± 0.11 in 2M NaClO 4 ; log β 1 / : - 9.02 ± 0.11, - 8.75 ± 0.01 and - 8.12 ± 0.03 in 2M NaCl and the values for log β 1,Cl were - 0.0255, - 0.155 and - 0.758, respectively. (Author)

  8. effects of sulphur addition on addition on and mechanical properties

    African Journals Online (AJOL)

    User

    on the microstructure and mechanical properties of sand cast been investigated ... owed that the addition of sulphur to Al-12wt%Si alloy. 12wt%Si alloy .... 28 materials. 29. Element. Aluminum. Silicon. Al. Si. Ca. Fe. Cu. Zn. Mn. Mg. Cr. B. 99.71.

  9. Investigation of the crystal structure of a basic bismuth(III) nitrate with the composition [Bi6O4(OH)(4)](0.54(1))[Bi6O5(OH)(3)](0.46(1))(NO3)(5.54(1))

    DEFF Research Database (Denmark)

    Christensen, Axel Norlund; Lebech, Bente

    2012-01-01

    A basic bismuth(III) nitrate with the composition [Bi6O4(OH)(4)](0.5)[Bi6O5(OH)(3)](0.5)(NO3)(5.5) formed in a slow crystal growth mode has an ordered crystal structure with the monoclinic space group P2(1) and lattice parameters a = 15.850(3), b = 14.986(3), c = 18.230(4) angstrom, beta = 107...... a trigonal R (3) over bar cell with a = 15.1865(1) and c = 15.8416(1) angstrom (hexagonal setting). In a Rietveld type structure model refinement with a total of 28 atom sites (4 Bi, 3 N, 15 O and 6 H), the composition of this sample is determined to be [Bi6O4(OH)(4)](0.54(1))[Bi6O5(OH)(3)](0.46(1))(NO3)(5.54(1))....

  10. Hydrogen Generation from Al-NiCl2/NaBH4 Mixture Affected by Lanthanum Metal

    Directory of Open Access Journals (Sweden)

    Wen Qiang Sun

    2012-01-01

    Full Text Available The effect of La on Al/NaBH4 hydrolysis was elaborated in the present paper. Hydrogen generation amount increases but hydrogen generation rate decreases with La content increasing. There is an optimized composition that Al-15 wt% La-5 wt% NiCl2/NaBH4 mixture (Al-15 wt% La-5 wt% NiCl2/NaBH4 weight ratio, 1 : 3 has 126 mL g−1 min−1 maximum hydrogen generation rate and 1764 mL g−1 hydrogen generation amount within 60 min. The efficiency is 88%. Combined with NiCl2, La has great effect on NaBH4 hydrolysis but has little effect on Al hydrolysis. Increasing La content is helpful to decrease the particle size of Al-La-NiCl2 in the milling process, which induces that the hydrolysis byproduct Ni2B is highly distributed into Al(OH3 and the catalytic reactivity of Ni2B/Al(OH3 is increased therefore. But hydrolysis byproduct La(OH3 deposits on Al surface and leads to some side effect. The Al-La-NiCl2/NaBH4 mixture has good stability in low temperature and its hydrolytic performance can be improved with increasing global temperature. Therefore, the mixture has good safety and can be applied as on board hydrogen generation material.

  11. Effect of Al_2O_3 addition on ceramic-type semiconductor NTC from NiO and CO_3O_4 and characterization of electrical conductivity indirect via constant current source

    International Nuclear Information System (INIS)

    Machado, L.V.R.; Moraes, E.T.; Correa, R.R.

    2011-01-01

    The NTC has been used as a temperature sensor, protection of electrical equipment, hospital instruments and automotive industry, thereby justifying its study. This pottery was processed, by a Spex mill by varying the concentration of Al_2O_3 in the oxides calcined at 1100 ° C to form the desired phases, then compressed to 120 MPa in a mold of 10mm"2 in size and 3mm thick and sintered at 1200 ° C and 1300 ° C, thermogravimetric analysis and DSC justified these temperatures. The XRD was used as powder for phase identification and FEG present in the pastilles to check the influence of microstructure on electrical property. A DC characterization was presented in an indirect way, by measuring the voltage through a constant current source, which eliminates the effect of the positive feedback generated by Joule effect. The electrical conductance is determined by Ohm's law. Samples with higher content of Al_2O_3 showed lower electrical conductivity. (author)

  12. Ti, Al

    Indian Academy of Sciences (India)

    In the present study, authors report on the effect that substrate bias voltage has on the microstructure and mechanical properties of (Ti, Al)N hard coatings deposited with cathodic arc evaporation (CAE) technique. The coatings were deposited from a Ti0.5Al0.5 powder metallurgical target in a reactive nitrogen atmosphere at ...

  13. The Influence of Backwater Al3+ on Diaspore Bauxite Flotation

    Directory of Open Access Journals (Sweden)

    Chaojun Fang

    2017-10-01

    Full Text Available The effect of Al3+ in backwater on the flotation of diaspore bauxite was investigated by micro-flotation tests and the underlying mechanisms were investigated by inductively coupled plasma (ICP measurement, zeta potential measurements, solution chemistry analyses, and synchrotron near edge X-ray absorption fine structure (NEXAFS analyses. The ICP measurement results show the concentration of Al3+ in backwater was up to 1 × 10−4 mol/L. The micro-flotation results indicated that backwater Al3+ reduced the flotation recovery of diaspore and improved the flotation recovery of kaolinite at pH 9, which was the pH value used in the industrial flotation. The adsorption of Al3+ species changed the zeta potential, the Al atomic abundance, and the number of active sites on the mineral surface. In particular, the result of solution chemistry analyses and synchrotron NEXAFS analyses show that the Al3+ in backwater was adsorbed on the mineral surface in the form of Al(OH3 (s, and the bond of –Al–O–Al–(OH2 or –Al/Si–O–Al–(OH2 was formed at pH 9. It changed the intensity of hydrogen bond force between minerals and collectors, and resulted in the depression of diaspore flotation and the activation of kaolinite flotation. This study can be used to guide the application of backwater in the flotation of diaspore bauxite in industry.

  14. The Additively Manufactured Porous NiTi and Ti-6Al-4V in Mandibular Reconstruction: Introducing the Stiffness-Matched and the Variable Stiffness Options for the Reconstruction Plates

    Science.gov (United States)

    Jahadakbar, Ahmadreza

    Mandibular reconstruction surgery is a part of treatment for cancer, tumor, and all the cases that involve segmental defects. One of the most common approaches for the reconstruction surgery is to resect the segmental defect and use a double barrel fibula graft to fill the resected region and recover the mandible's normal functions, such as chewing. The grafted bone is connected to the host mandible, using the standard of the care Ti-6Al-4V fixation plates. The fixation plates are available in the form of prefabricated plates and also patient-specific plates in the market. Due to the high stiffness of the Ti-6Al-4V plates in comparison with the mandible bone and the grafted bone, the loading distribution on the whole reconstructed mandible will be different from a healthy mandible. The high stiffness fixation hardware carries a great portion of the loading and causes stress shielding on the grafted bone and the surrounding host bone. Based on the bone remodeling theory, the stress shielding on the cortical bone causes bone resorption and may lead to implant failure. A solution to reduce the risk of implant failure is to use a low stiffness biocompatible material for the mandibular fixation plates. We have proposed the use of stiffness-matched, porous NiTi fixation plates either in the form of patient-specific or prefabricated, instead of the standard of the care Ti-6Al-4V plates. NiTi is a biocompatible material that has a low stiffness in comparison with Ti-6Al-4V and also benefits from the superelastic feature. Superelasticity, which can also be found in bone tissues, allows the material to recover large strains (up to 8%) and increases the shock absorption. In this thesis, we have evaluated the use of proposed fixation hardware by comparing it with a healthy mandible and a reconstructed mandible using the standard method. To this end, first different models including a healthy mandible, a reconstructed mandible using patient-specific Ti-6Al-4V fixation hardware

  15. Effects of Process Conditions on the Mechanical Behavior of Aluminium Wrought Alloy EN AW-2219 (AlCu6Mn Additively Manufactured by Laser Beam Melting in Powder Bed

    Directory of Open Access Journals (Sweden)

    Michael Cornelius Hermann Karg

    2017-01-01

    Full Text Available Additive manufacturing is especially suitable for complex-shaped 3D parts with integrated and optimized functionality realized by filigree geometries. Such designs benefit from low safety factors in mechanical layout. This demands ductile materials that reduce stress peaks by predictable plastic deformation instead of failure. Al–Cu wrought alloys are established materials meeting this requirement. Additionally, they provide high specific strengths. As the designation “Wrought Alloys” implies, they are intended for manufacturing by hot or cold working. When cast or welded, they are prone to solidification cracks. Al–Si fillers can alleviate this, but impair ductility. Being closely related to welding, Laser Beam Melting in Powder Bed (LBM of Al–Cu wrought alloys like EN AW-2219 can be considered challenging. In LBM of aluminium alloys, only easily-weldable Al–Si casting alloys have succeeded commercially today. This article discusses the influences of boundary conditions during LBM of EN AW-2219 on sample porosity and tensile test results, supported by metallographic microsections and fractography. Load direction was varied relative to LBM build-up direction. T6 heat treatment was applied to half of the samples. Pronounced anisotropy was observed. Remarkably, elongation at break of T6 specimens loaded along the build-up direction exceeded the values from literature for conventionally manufactured EN AW-2219 by a factor of two.

  16. Improvement of photoluminescence properties and thermal stability of Y{sub 2.9}Ce{sub 0.1}Al{sub 5−x}Si{sub x}O{sub 12} phosphors with Si{sub 3}N{sub 4} addition

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Fangfang [College of Electronic Information and Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Song, Kaixin, E-mail: kxsong@hdu.edu.cn [College of Electronic Information and Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Jiang, Jun [Ningbo Institute of Materials Technologies and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Wu, Song; Zheng, Peng [College of Electronic Information and Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Huang, Qingming [Instrument Analysis and Testing Center, Fuzhou University, Fuzhou 350002 (China); Xu, Junming; Qin, Huibin [College of Electronic Information and Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China)

    2014-12-05

    Highlights: • Y{sub 2.9}Ce{sub 0.1}Al{sub 5−x}Si{sub x}O{sub 12} phosphors were prepared by solid-state reaction in reduced air ambience. • Si{sup 4+} could be incorporated into the host lattice of Y{sub 3}Al{sub 5}O{sub 12} through partial occupation of the Al{sup 3+} sites. • Si{sub 3}N{sub 4} addition can improve photoluminescence efficiency and thermal stability of Y{sub 3}Al{sub 5}O{sub 12}:Ce. - Abstract: A series of Si{sub 3}N{sub 4} doping Y{sub 2.9}Ce{sub 0.1}Al{sub 5−x}Si{sub x}O{sub 12−3x/2}N{sub 4x/3} phosphors were prepared by solid-state reaction in 95%N{sub 2}–5%H{sub 2} reduced air ambience. The XRD characteristics plus Rietveld refinement results shows that the as-sintered powders are unique crystal phase with the same crystal structure of Y{sub 3}Al{sub 5}O{sub 12} (PDF No. 79-1891). The N element was not detected by the analysis of X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectrum (EDS). The photoluminescence spectra (PL and PLE) tests show that the exciting and emitting intensity of PLE and PL gradually increase due to the increase of Si{sub 3}N{sub 4} concentration. Meanwhile, the phosphorescence decay times are prolonged from 45 ns (x = 0) to 78 ns (x = 0.3), under the monitor of 530 nm wavelength. The thermoluminescence tests (TL) confirm the thermal stability of as-phosphors with Si{sub 3}N{sub 4} addition is much better than that of the pristine Y{sub 2.9}Ce{sub 0.1}Al{sub 5}O{sub 12} phosphors.

  17. AL Amyloidosis

    Directory of Open Access Journals (Sweden)

    Desport Estelle

    2012-08-01

    Full Text Available Abstract Definition of the disease AL amyloidosis results from extra-cellular deposition of fibril-forming monoclonal immunoglobulin (Ig light chains (LC (most commonly of lambda isotype usually secreted by a small plasma cell clone. Most patients have evidence of isolated monoclonal gammopathy or smoldering myeloma, and the occurrence of AL amyloidosis in patients with symptomatic multiple myeloma or other B-cell lymphoproliferative disorders is unusual. The key event in the development of AL amyloidosis is the change in the secondary or tertiary structure of an abnormal monoclonal LC, which results in instable conformation. This conformational change is responsible for abnormal folding of the LC, rich in β leaves, which assemble into monomers that stack together to form amyloid fibrils. Epidemiology AL amyloidosis is the most common type of systemic amyloidois in developed countries with an estimated incidence of 9 cases/million inhabitant/year. The average age of diagnosed patients is 65 years and less than 10% of patients are under 50. Clinical description The clinical presentation is protean, because of the wide number of tissues or organs that may be affected. The most common presenting symptoms are asthenia and dyspnoea, which are poorly specific and may account for delayed diagnosis. Renal manifestations are the most frequent, affecting two thirds of patients at presentation. They are characterized by heavy proteinuria, with nephrotic syndrome and impaired renal function in half of the patients. Heart involvement, which is present at diagnosis in more than 50% of patients, leading to restrictive cardiopathy, is the most serious complication and engages prognosis. Diagnostic methods The diagnosis relies on pathological examination of an involved site showing Congo red-positive amyloid deposits, with typical apple-green birefringence under polarized light, that stain positive with an anti-LC antibody by immunohistochemistry and

  18. Estudo microestrutural do catalisador Ni/gama-Al2O3: efeito da adição de CeO2 na reforma do metano com dióxido de carbono Microstructural study of Ni/gamma-Al2O3 catalyst: addition effects of CeO2 on carbon dioxide reforming of methane

    Directory of Open Access Journals (Sweden)

    Antoninho Valentini

    2003-10-01

    Full Text Available The carbon dioxide reforming of methane was carried out over nickel catalysts supported on the gamma-Al2O3/CeO2 system prepared by wet impregnation. With the increase of the CeO2 weight in the catalyst, a higher stability was observed in the catalytic activity, together with an excellent resistance to carbon deposition and a better Ni dispersion. The catalysts were characterized by means of surface area measurements, TPR, H2 chemisorption, XRD, SEM, EDX, XPS and TEM. An interaction between Ni and CeO2 was observed to the Ni/CeO2 sample after activation in a H2 atmosphere above 300 ºC. Such behavior has a significantly influence on the catalytic activity.

  19. Dehydration of δ-AlOOH in the lower mantle

    Science.gov (United States)

    Piet, H.; Shim, S. H.; Tappan, J.; Leinenweber, K. D.; Greenberg, E.; Prakapenka, V. B.

    2017-12-01

    Hydrous phase δ-AlOOH is an important candidate for water transport and storage in the Earth's deep mantle [1]. Knowing the conditions, under which it is stable and dehydrated, is therefore important for understanding the water transportation to the deep mantle or even to the core. A few experimental studies [1, 2] have shown that δ-AlOOH may be stable in cold descending slabs while it is dehydrated into a mixture of corundum and water under normal mantle conditions, up to 25 GPa. A subsequent study [3] reported the stability of δ-AlOOH in cold descending slabs to the core-mantle boundary conditions (2300 K at 135 GPa). However, the dehydration of δ-AlOOH has not bee directly observed in the experiments conducted at pressures above 25 GPa. We have synthesized δ-AlOOH from diaspore and Al(OH)3 in multi-anvil press at ASU. The sample was mixed with Au for coupling with near IR laser beams and loaded in diamond-anvil cells. We performed the laser-heated diamond anvil cell experiments at the 13IDD beamline of the Advanced Photon Source and ASU. At APS, we measured X-ray diffraction patterns at in situ high pressure and temperature. We observed the appearance of the corundum diffraction lines at 1700-2000 K and 55-90 GPa, indicating the dehydration of δ-AlOOH to Al2O3+ H2O. We found that the transition occurs over a broad range of temperature (500 K). We also observed that the dehydration of δ-AlOOH was accompanied by sudden change in laser coupling, most likely due to the release of fluids. The property change also helps us to determine the dehydration at ASU without in situ XRD. Our new experimental results indicate that δ-AlOOH would be stable in most subducting slabs in the deep mantle. However, because the dehydration occurs very close to the temperatures expected for the lower mantle, its stability is uncertain in the normal mantle. [1] Ohtani et al. 2001, Stability field of new hydrous phase, delta-AlOOH, Geophysical Research Letters 28, 3991-3993. [2

  20. Crystallization of mordenite zeolite with seed addition in reaction mixtures with different SiO{sub 2}/Al{sub 2}O{sub 3} ratios; Cristalizacao da zeolita mordenita com adicao de sementes em meio reacionais com diferentes razoes SiO{sub 2}/Al{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Cysneiros, O.M.S.; Silva, B.J.B.; Silva, A.O.S.; Alencar, S.L.; Santos, R.B.; Soares, P.F.M.; Mendonca, T.R.D.; Sousa Junior, L.V.; Santos, J.R., E-mail: brunojbarros@hotmail.com [Universidade Federal de Alagoas (UFAL), Maceio (Brazil). Departamento de Engenharia Quimica. Laboratorio de Sintese de Catalisadores

    2016-04-15

    The synthesis of samples of mordenite were performed using the hydrothermal method using two different types of crystallization seed (mordenite and ferrierite), where they were exploited to change some parameters of the synthesis, such as SiO{sub 2}/Al{sub 2}O{sub 3} = 20, 60 and 100 and the ratio OH/SiO{sub 2} = 0.2, 0.3 and 0.4, at different times of crystallization, at a temperature of 170 °C. The samples were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA/DTA), nitrogen adsorption at -196 °C (BET) and temperature programmed desorption of ammonia (NH{sub 3}-TPD). It was found that the use of the ratio OH/SiO{sub 2} = 0.4, together with the seeds of the most MOR and FER crystalline samples were obtained, demonstrating the critical role of mineralizing agent OH{sup -} in the middle. (author)

  1. Deficiência da 3-OH-3-metil-glutaril-CoA-liase como causa de coma no período neonatal: relato de caso 3-hydroxy-3-methylglutaryl-CoA-lyase deficiency as coma etiology in the neonatal period: case report

    Directory of Open Access Journals (Sweden)

    ERASMO BARBANTE CASELLA

    1998-09-01

    Full Text Available Estudamos um paciente que apresentou dois episódios de coma no primeiro mês de vida, com descompensação metabólica, nos quais se observou hipoglicemia e acidose metabólica acentuada, sem cetonúria. O estudo dos ácidos orgânicos urinários demonstrou elevação acentuada de 3-OH-3-metil-glutárico, 3-metil-glutacônico, 3-metil-glutárico e 3-OH-isovalérico. Os sinais e sintomas clínicos associados às alterações metabólicas citadas permitiram o diagnóstico da deficiência da 3-OH-3-metil-glutaril-CoA-liase, entidade de origem autossômica recessiva, passível de ser tratada, como no caso estudado, com dieta hipoproteica, restrita em leucina, hipogordurosa e rica em carboidratos, associada a L-carnitina e evitando-se períodos prolongados de jejum.We report a patient that presented two episodes of coma in the neonatal period, with severe metabolic acidosis and hypoglycemia, without ketosis. The urinary organic acid analysis showed increased amounts of 3-hydroxy-3-methyl-glutaric, 3-methylglutaconic, 3-methylglutaric and 3-hydroxyisovaleric acid. The deficiency of 3-hydroxy-3-methylglutaryl-CoA lyase was diagnosed by the clinical and metabolic features. This disease shows autosomal recessive inheritance and the treatment is done by a diet with restriction of protein (mainly leucine and lipids, high in carbohydrate content, and the avoidance of fasting and carnitine supplementation.

  2. Current generation in microbial electrolysis cells with addition of amorphous ferric hydroxide, Tween 80, or DNA

    KAUST Repository

    Ren, Lijiao

    2012-11-01

    Iron-oxide nanoparticles and the Tween 80 have previously been shown to improve power generation in microbial fuel cells (MFCs), presumably by improving electron transfer from the bacteria to the anode. We examined whether several chemicals would affect current production in single-chamber microbial electrolysis cells (MECs), where hydrogen gas is produced at the cathode, using mixed cultures and Geobacter sulfurreducens. Tween 80 did not increase the current. Fe(OH) 3 addition increased the maximum current density of both the mixed cultures (from 6.1 ± 0.9 A/m 2 to 8.8 ± 0.3 A/m 2) and pure cultures (from 4.8 ± 0.5 A/m 2 to 7.4 ± 1.1 A/m 2). Improved current production was sustained even after iron was no longer added to the medium. It was demonstrated that increased current resulted from improved cathode performance. Analysis using electrochemical impedance spectroscopy (EIS) showed that the iron primarily reduced the diffusion resistances of the cathodes, and scanning electron microscopy (SEM) images showed the formation of highly porous structures on the cathode. The addition of DNA also did not improve MEC or MFC performance. These results demonstrated that among these treatments only Fe(OH) 3 addition was a viable method for enhancing current densities in MECs, primarily by improving cathode performance. Copyright © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights.

  3. Combustion synthesis of AlB2-Al2O3 composite powders with AlB2 nanowire structures

    Science.gov (United States)

    Yang, Pan; Xiao, Guoqing; Ding, Donghai; Ren, Yun; Yang, Shoulei; Lv, Lihua; Hou, Xing

    2018-05-01

    Using of Al and B2O3 powders as starting materials, and Mg-Al alloy as additives, AlB2-Al2O3 composite powders with AlB2 nanowire structures were successfully fabricated via combustion synthesis method in Ar atmosphere at a pressure of 1.5 MPa. The effect of different amount of Mg-Al alloy on the phase compositions and morphology of the combustion products was investigated. The results revealed that AlB2 and Al2O3 increased, whereas Al decreased with the content of Mg-Al alloy increasing. The impurities MgAl2O4 and AlB12 would exist in the sample with adding of 18 wt% Mg-Al alloy. Interestingly, FESEM/TEM/EDS results showed that AlB2 nanowires were observed in the products when the content of Mg-Al alloy is 6 wt% and 12 wt%. The more AlB2 nanowires can be found as the content of Mg-Al alloy increased. And the yield of AlB2 nanowires with the diameter of about 200 nanometers (nm) and the length up to several tens of micrometers (μm) in the combustion product is highest when the content of Mg-Al alloy is 12 wt%. The vapor, such as Mg-Al (g), B2O2 (g), AlO (g) and Al2O (g), produced during the process of combustion synthesis, reacted with each other to yield AlB2 nanowires by vapor-solid (VS) mechanism and the corresponding model was also proposed.

  4. Additive Manufactured Superconducting Cavities

    Science.gov (United States)

    Holland, Eric; Rosen, Yaniv; Woolleet, Nathan; Materise, Nicholas; Voisin, Thomas; Wang, Morris; Mireles, Jorge; Carosi, Gianpaolo; Dubois, Jonathan

    Superconducting radio frequency cavities provide an ultra-low dissipative environment, which has enabled fundamental investigations in quantum mechanics, materials properties, and the search for new particles in and beyond the standard model. However, resonator designs are constrained by limitations in conventional machining techniques. For example, current through a seam is a limiting factor in performance for many waveguide cavities. Development of highly reproducible methods for metallic parts through additive manufacturing, referred to colloquially as 3D printing\\x9D, opens the possibility for novel cavity designs which cannot be implemented through conventional methods. We present preliminary investigations of superconducting cavities made through a selective laser melting process, which compacts a granular powder via a high-power laser according to a digitally defined geometry. Initial work suggests that assuming a loss model and numerically optimizing a geometry to minimize dissipation results in modest improvements in device performance. Furthermore, a subset of titanium alloys, particularly, a titanium, aluminum, vanadium alloy (Ti - 6Al - 4V) exhibits properties indicative of a high kinetic inductance material. This work is supported by LDRD 16-SI-004.

  5. Construction of g-C_3N_4/Al_2O_3 hybrids via in-situ acidification and exfoliation with enhanced photocatalytic activity

    International Nuclear Information System (INIS)

    Wang, Xiao-jing; Liu, Chao; Li, Xu-li; Li, Fa-tang; Li, Yu-pei; Zhao, Jun; Liu, Rui-hong

    2017-01-01

    Highlights: • Ultrathin g-C_3N_4/Al_2O_3 hybrids are prepared via in-situ reaction. • The structure modification role of in-situ formed HNO_3 for g-C_3N_4 is found. • The ultrathin g-C_3N_4 nanosheets are formed by the acidified melamine and Al(OH)_3. • In-situ calcination of melamine and Al(OH)_3 benefits the contact of C_3N_4 and Al_2O_3. • The activity of g-C_3N_4/Al_2O_3 is 16.6 times that of pristine g-C_3N_4 in degrading RhB. - Abstract: Homogeneous ultrathin g-C_3N_4 nanosheets/Al_2O_3 heterojunctions are synthesized using melamine and Al(NO_3)_3 via in-situ reaction and the following thermal polymerization approach. The in-situ reaction between melamine and Al(NO_3)_3 results in the existence of HNO_3-acidified melamine and Al(OH)_3 aggregates via the hydrolysis of Al(NO_3)_3. After thermal polymerization, the aggregates are converted to g-C_3N_4/Al_2O_3 composites. The thermal polymerization of acidified melamine and the support effect of aluminum hydroxide for g-C_3N_4 during the calcination process lead to highly dispersed amrophous Al_2O_3 on ultrathin g-C_3N_4 nanosheets, which is beneficial for the separation of photogenerated electron-hole pairs in the heterojunction. The degradation rate for Rhodamine B (RhB) over the most activie sample is 16.6 times than that of pristine g-C_3N_4 under visible light irradiation, which can be attributed to the high specific surface area, highly dispersion of amorphous Al_2O_3 on ultrathin g-C_3N_4 nanosheet, and the effective electrons transfer from g-C_3N_4 to the amorphous Al_2O_3.

  6. United modification of Al-24Si alloy by Al-P and Al-Ti-C master alloys

    Institute of Scientific and Technical Information of China (English)

    韩延峰; 刘相法; 王海梅; 王振卿; 边秀房; 张均艳

    2003-01-01

    The modification effect of a new type of Al-P master alloy on Al-24Si alloys was investigated. It is foundthat excellent modification effect can be obtained by the addition of this new type of A1-P master alloy into Al-24Simelt and the average primary Si grain size is decreased below 47 μm from original 225 μm. It is also found that theTiC particles in the melt coming from Al8Ti2C can improve the modification effect of the Al-P master alloy. Whenthe content of TiC particles in the Al-24Si melt is 0.03 %, the improvement reaches the maximum and keeps steadywith increasing content of TiC particles. Modification effect occurs at 50 min after the addition of the Al-P master al-loy and TiC particles, and keeps stable with prolonging holding time.

  7. Estimation of the additive and dominance variances in SA Landrace ...

    African Journals Online (AJOL)

    NORRIS

    South African Journal of Animal Science 2006, 36 (4) ... Fuerst (1996) simulated a genetic model with different levels of additive, dominance and additive by additive genetic effects to .... However, a simulation study by Norris et al. (2002) ...

  8. Li{sub 4}SiO{sub 4} based breeder ceramics with Li{sub 2}TiO{sub 3}, LiAlO{sub 2} and Li{sub X}La{sub Y}TiO{sub 3} additions, part I: Fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Kolb, M.H.H., E-mail: Matthias.kolb@kit.edu [Karlsruhe Institute of Technology, Institute for Applied Materials, PO Box 3640, 76021 Karlsruhe (Germany); Mukai, K.; Knitter, R. [Karlsruhe Institute of Technology, Institute for Applied Materials, PO Box 3640, 76021 Karlsruhe (Germany); Hoshino, T. [Breeding Functional Materials Development Group, Department of Blanket Systems Research, Rokkasho Fusion Institute, Fusion Energy Research and Development Directorate, National Institutes for Quantum and Radiological Science and Technology (QST) (Japan)

    2017-02-15

    Highlights: • This study shows that the emulsion method can easily be adapted to add different phases into Li4SiO4 breeder pebbles. • Slurries with various compositions to form LOS + LMT, LOS + LAO and LOS + LLTO were processed.The calculated activation behavior shows that samples with added LAO or LLTO qualify as low activation material. • Yet, the long-term activation of the LAO containing samples is problematic as hands-on level activity is not reached quickly. - Abstract: Wet-chemical fabrication processes are highly adaptable to a wide range of raw materials and are therefore well suited for evaluating new material compositions. Here the established emulsion method was modified to fabricate novel two-phase Li{sub 4}SiO{sub 4} pebbles of 1 mm diameter with additions of Li{sub 2}TiO{sub 3}, LiAlO{sub 2} or Li{sub x}La{sub y}TiO{sub 3}. As the lithium density of the latter two compounds is relatively low, only moderate contents were added. The Li{sub 2}TiO{sub 3} additions, however, cover the full compositional range. The fabrication process was characterized with regard to its constancy and aptness for the anticipated pebble compositions by optical pebble size measurements. Also the phase content and the elemental composition of the fabricated pebbles were analyzed by XRD and ICP-OES combined with XRF, respectively. This work shows that the emulsion method is an appropriate method to produce pebbles with the anticipated Li{sub 2}TiO{sub 3} and LiAlO{sub 2} concentrations in a Li{sub 4}SiO{sub 4} matrix. However, Li{sub 4}SiO{sub 4} and Li{sub x}La{sub y}TiO{sub 3} react with each other to a number of different phases. To evaluate the activation properties of the pebbles, FISPACT calculations with a DEMO relevant neutron source are applied as well. The addition of aluminum seems to be unfavorable for a fusion application, but moderate concentrations of lanthanum can be tolerated.

  9. Li{sub 4}SiO{sub 4} based breeder ceramics with Li{sub 2}TiO{sub 3}, LiAlO{sub 2} and Li{sub X}La{sub Y}TiO{sub 3} additions, part II: Pebble properties

    Energy Technology Data Exchange (ETDEWEB)

    Kolb, M.H.H., E-mail: Matthias.kolb@kit.edu [Karlsruhe Institute of Technology, Institute for Applied Materials, PO Box 3640, 76021, Karlsruhe (Germany); Knitter, R. [Karlsruhe Institute of Technology, Institute for Applied Materials, PO Box 3640, 76021, Karlsruhe (Germany); Hoshino, T. [Breeding Functional Materials Development Group, Department of Blanket Systems Research, Rokkasho Fusion Institute, Fusion Energy Research and Development Directorate, National Institutes for Quantum and Radiological Science and Technology (QST) (Japan)

    2017-02-15

    Highlights: • The mechanical strength of Li{sub 4}SiO{sub 4}-based breeder pebbles can be improved by adding either LMT, LAO or LLTO as second phase. • The increase in strength is closely linked to a reduction of the open porosity of the pebbles. • All fabricated pebbles show a highly homogenous microstructure with mostly low closed porosity. • Adding LLTO, although it decomposes during sintering, greatly improves the strength of the pebbles. - Abstract: The pebble properties of novel two-phase Li{sub 4}SiO{sub 4} pebbles of 1 mm diameter with additions of Li{sub 2}TiO{sub 3}, LiAlO{sub 2} or Li{sub x}La{sub y}TiO{sub 3} are evaluated in this work as a function of the second phase concentration and the microstructure of the pebbles. The characterization focused on the mechanical strength, microstructure and open as well as closed porosity. Therefore crush load tests, SEM analyses as well as helium pycnometry and optical image analysis were performed, respectively. This work shows that generally additions of a second phase to Li{sub 4}SiO{sub 4} considerably improve the mechanical strength. It also shows that the fabrication processes have to be well-controlled to achieve high mechanical strengths. When Li{sub 2}TiO{sub 3} is added in different concentrations, the determinant for the crush load seems to be the open porosity of the pebbles. The strengthening effect of LiAlO{sub 2} compared to Li{sub 2}TiO{sub 3} is similar, while additions of Li{sub x}La{sub y}TiO{sub 3} increase the mechanical strength much more. Yet, Li{sub 4}SiO{sub 4} and Li{sub x}La{sub y}TiO{sub 3} react with each other to a number of different phases upon sintering. In general the pebble properties of all samples are favorable for use within a fusion breeder blanket.

  10. Crystal structure of (Al,V)4(P4O12)3, archetype of double cubic ring tetraphosphate

    International Nuclear Information System (INIS)

    Yakubovich, O. V.; Biralo, G. V.; Dimitrova, O. V.

    2012-01-01

    The crystal structure of the (Al,V) 4 (P 4 O 12 ) 3 solid solution, obtained in the single-crystal form by hydrothermal synthesis in the Al(OH) 3 -VO 2 -NaCl-H 3 PO 4 -H 2 O system, has been solved by X-ray diffraction analysis (Xcalibur-S-CCD diffractometer, R = 0.0257): a = 13.7477(2) Å, sp. gr. I 4 bar 3d, Z = 4, and ρ calcd = 2.736 g/cm 3 . It is shown that the crystal structure of the parent cubic Al 4 (P 4 O 12 ) 3 modification can formally be considered an archetype for the formation of double isosymmetric tetraphosphates on its basis.

  11. All About ALS

    Science.gov (United States)

    ... Subscribe August 2015 Print this issue All About ALS Understanding a Devastating Disorder En español Send us ... Sports Concussions Wise Choices How Can I Help ALS Research? If you have ALS, join the National ...

  12. Harnessing the Potential of Additive Manufacturing

    Science.gov (United States)

    2016-12-01

    31 Defense AT&L: November-December 2016 Harnessing the Potential of Additive Manufacturing Bill Decker Decker is director of Technology...achieve its goal of competition throughout the acquisition life cycle. When we look at additive manufacturing , we have a much different environment. To...Titanium-6 Aluminum-4 Vanadium with Powder Bed Fusion. This specification covers additively manufactured titanium-6 aluminum-4 vanadium (Ti-6Al-4V

  13. The application of DTA and TG methods to investigate the non-crystalline hydration products of CaAl2O4 and Ca7ZrAl6O18 compounds

    International Nuclear Information System (INIS)

    Szczerba, Jacek; Madej, Dominika; Śnieżek, Edyta; Prorok, Ryszard

    2013-01-01

    Highlights: ► Hydrates, i.e. CAH 10 , C 2 AH 8 , C 3 AH 6 and C 4 AH 19 are formed during hydration of CaAl 2 O 4 and Ca 7 ZrAl 6 O 18 . ► Hydrated CaAl 2 O 4 and Ca 7 ZrAl 6 O 18 compounds were investigated by X-ray diffraction, SEM/EDS and thermal analysis. ► The hydration reaction proceeds as consumes the unreacted core of the CaAl 2 O 4 and Ca 7 ZrAl 6 O 18 grain. - Abstract: The hydration products and thermal decomposition mechanism of hydrated CaAl 2 O 4 and Ca 7 ZrAl 6 O 18 compounds were investigated by X-ray diffraction, SEM/EDS and thermal analysis. The processes of crystal hydrate nucleation and precipitation were preceded by the evolution of the X-ray amorphous phase during the first 24 h of hydration. DTA–TGA–EGA techniques allowed the study of the detailed decomposition and identification of intermediate and stable to be performed. The differential thermal analysis (DTA) curves of hydrated CaAl 2 O 4 and Ca 7 ZrAl 6 O 18 compounds show five similar endothermic peaks due to crystal water desorption. According to the quantitative TGA–EGA analyses performed on hydrated CaAl 2 O 4 and Ca 7 ZrAl 6 O 18 compounds, it was found that C 2 AH 8 , C 3 AH 6 and Al(OH) 3 phases are the main hydration products of CaAl 2 O 4 . Under the same laboratory conditions, the hydration of Ca 7 ZrAl 6 O 18 proceeds with the formation of mainly CAH 10 and AH 3 -gel phases. We provide the original illustrations of the hydrate crystals formation via amorphous phases

  14. Photodriven hydrogen evolution by molecular catalysts using Al2O3-protected perylene-3,4-dicarboximide on NiO electrodes† †Electronic supplementary information (ESI) available: Experimental details; additional electrochemical and photoelectrochemical characterization, UV-Vis spectra, and fsTA results; quantification of evolved hydrogen; and DFT-computed ground state structure of PMI diester. See DOI: 10.1039/c6sc02477g Click here for additional data file.

    Science.gov (United States)

    Kamire, Rebecca J.; Majewski, Marek B.; Hoffeditz, William L.; Phelan, Brian T.; Farha, Omar K.; Hupp, Joseph T.

    2017-01-01

    The design of efficient hydrogen-evolving photocathodes for dye-sensitized photoelectrochemical cells (DSPECs) requires the incorporation of molecular light absorbing chromophores that are capable of delivering reducing equivalents to molecular proton reduction catalysts at rates exceeding those of charge recombination events. Here, we report the functionalization and kinetic analysis of a nanostructured NiO electrode with a modified perylene-3,4-dicarboximide chromophore (PMI) that is stabilized against degradation by atomic layer deposition (ALD) of thick insulating Al2O3 layers. Following photoinduced charge injection into NiO in high yield, films with Al2O3 layers demonstrate longer charge separated lifetimes as characterized via femtosecond transient absorption spectroscopy and photoelectrochemical techniques. The photoelectrochemical behavior of the electrodes in the presence of Co(ii) and Ni(ii) molecular proton reduction catalysts is examined, revealing reduction of both catalysts. Under prolonged irradiation, evolved H2 is directly observed by gas chromatography supporting the applicability of PMI embedded in Al2O3 as a photocathode architecture in DSPECs. PMID:28616134

  15. Additive Manufacturing Infrared Inspection

    Science.gov (United States)

    Gaddy, Darrell; Nettles, Mindy

    2015-01-01

    The Additive Manufacturing Infrared Inspection Task started the development of a real-time dimensional inspection technique and digital quality record for the additive manufacturing process using infrared camera imaging and processing techniques. This project will benefit additive manufacturing by providing real-time inspection of internal geometry that is not currently possible and reduce the time and cost of additive manufactured parts with automated real-time dimensional inspections which deletes post-production inspections.

  16. [Food additives and healthiness].

    Science.gov (United States)

    Heinonen, Marina

    2014-01-01

    Additives are used for improving food structure or preventing its spoilage, for example. Many substances used as additives are also naturally present in food. The safety of additives is evaluated according to commonly agreed principles. If high concentrations of an additive cause adverse health effects for humans, a limit of acceptable daily intake (ADI) is set for it. An additive is a risk only when ADI is exceeded. The healthiness of food is measured on the basis of nutrient density and scientifically proven effects.

  17. In Situ Fabrication of AlN Coating by Reactive Plasma Spraying of Al/AlN Powder

    Directory of Open Access Journals (Sweden)

    Mohammed Shahien

    2011-10-01

    Full Text Available Reactive plasma spraying is a promising technology for the in situ formation of aluminum nitride (AlN coatings. Recently, it became possible to fabricate cubic-AlN-(c-AlN based coatings through reactive plasma spraying of Al powder in an ambient atmosphere. However, it was difficult to fabricate a coating with high AlN content and suitable thickness due to the coalescence of the Al particles. In this study, the influence of using AlN additive (h-AlN to increase the AlN content of the coating and improve the reaction process was investigated. The simple mixing of Al and AlN powders was not suitable for fabricating AlN coatings through reactive plasma spraying. However, it was possible to prepare a homogenously mixed, agglomerated and dispersed Al/AlN mixture (which enabled in-flight interaction between the powder and the surrounding plasma by wet-mixing in a planetary mill. Increasing the AlN content in the mixture prevented coalescence and increased the nitride content gradually. Using 30 to 40 wt% AlN was sufficient to fabricate a thick (more than 200 µm AlN coating with high hardness (approximately 1000 Hv. The AlN additive prevented the coalescence of Al metal and enhanced post-deposition nitriding through N2 plasma irradiation by allowing the nitriding species in the plasma to impinge on a larger Al surface area. Using AlN as a feedstock additive was found to be a suitable method for fabricating AlN coatings by reactive plasma spraying. Moreover, the fabricated coatings consist of hexagonal (h-AlN, c-AlN (rock-salt and zinc-blend phases and certain oxides: aluminum oxynitride (Al5O6N, cubic sphalerite Al23O27N5 (ALON and Al2O3. The zinc-blend c-AlN and ALON phases were attributed to the transformation of the h-AlN feedstock during the reactive plasma spraying. Thus, the zinc-blend c-Al

  18. Deletion of ALS5, ALS6 or ALS7 increases adhesion of Candida albicans to human vascular endothelial and buccal epithelial cells

    OpenAIRE

    ZHAO, XIAOMIN; OH, SOON-HWAN; HOYER, LOIS L.

    2007-01-01

    C. albicans yeast forms deleted for ALS5, ALS6 or ALS7 are more adherent than a relevant control strain to human vascular endothelial cell monolayers and buccal epithelial cells. In the buccal and vaginal reconstituted human epithelium (RHE) disease models, however, mutant and control strains caused a similar degree of tissue destruction. Deletion of ALS5 or ALS6 significantly slowed growth of the mutant strain; this phenotype was not affected by addition of excess uridine to the culture medi...

  19. Bipolar characteristics of AlGaN/AlN/GaN/AlGaN double heterojunction structure with AlGaN as buffer layer

    International Nuclear Information System (INIS)

    Peng, Enchao; Wang, Xiaoliang; Xiao, Hongling; Wang, Cuimei; Yin, Haibo; Chen, Hong; Feng, Chun; Jiang, Lijuan; Hou, Xun; Wang, Zhanguo

    2013-01-01

    Highlights: •2DEG and 2DHG coexist in the AlGaN/AlN/GaN/AlGaN DH-structure. •The sheet densities of 2DEG and 2DHG vary with buffer Al content and GaN thickness. •The conditions for the disappearance of 2DHG are discussed. •Increasing buffer Al content provides better electron confinement. •Dislocation scattering is reduced in the DH-structure. -- Abstract: This is a theoretical study of AlGaN/AlN/GaN/AlGaN double heterojunction (DH) structure with AlGaN as buffer layer. Our calculation shows that as the buffer Al content increases, though two-dimensional electron gas (2DEG) sheet density decreases, the channel back-barrier caused by polarization-induced electric field in GaN provides better electron confinement. And under certain conditions the DH-structure shows bipolar characteristics, with an additional two-dimensional hole gas (2DHG) formed at GaN/AlGaN interface. The influence of the buffer Al content and GaN channel thickness on the 2DEG and 2DHG sheet densities are investigated, and the conditions for the disappearance of 2DHG are discussed. Also, the mobility inhibited by dislocation scattering is enhanced in DH-structure due to the enhancement of screening effect of the 2DEG

  20. Coste-efectividad de la adición de acarbosa al tratamiento de pacientes con diabetes tipo 2 en España Cost-effectiveness of the addition of acarbose to the treatment of patients with type-2 diabetes in Spain

    Directory of Open Access Journals (Sweden)

    Carme Piñol

    2007-04-01

    Full Text Available Objetivos: Evaluar el coste-efectividad de la adición de acarbosa al tratamiento de pacientes con diabetes mellitus tipo 2 (DM2 en España. Métodos: Se utilizó el CORE Diabetes Model (modelo de simulación informática publicado y validado para proyectar a largo plazo los resultados clínicos y de costes de la DM2. Las probabilidades de transición y los riesgos se obtuvieron de distintas publicaciones. Los efectos del tratamiento y las características basales de la cohorte se obtuvieron de un metaanálisis. Los costes directos se extrajeron de diversas publicaciones y se proyectaron a lo largo de la vida de los pacientes bajo la perspectiva del Sistema Nacional de Salud de España. Los costes y beneficios fueron descontados en un 3% anual. Se realizaron análisis de sensibilidad. Resultados: El tratamiento con acarbosa se asoció con mejoras en la esperanza de vida (0,23 años y en los años de vida ajustados por calidad (AVAC (0,21 años. Los costes directos fueron en promedio, por paciente, de 468 € más caros con acarbosa que con placebo. La razón de coste-efectividad incremental fue de 2.002 €/año de vida ganado y de 2.199 €/AVAC ganado. La curva de aceptabilidad mostró que con una disponibilidad a pagar de 20.000 €, generalmente aceptada como muy buen valor monetario, el tratamiento con acarbosa se asoció con una probabilidad del 93,5% de ser coste-efectiva. Conclusiones: Este estudio económico a largo plazo mostró que la adición de acarbosa al tratamiento de pacientes con DM2 produjo mejoras en la esperanza de vida y en los AVAC de estos pacientes.Objectives: To assess the cost-effectiveness of the addition of acarbose to existing treatment in patients with type 2 diabetes mellitus (DM2 in Spain. Methods: The CORE Diabetes Model (a published and validated computer simulation model was used to project long-term clinical and cost outcomes in DM2. Transition probabilities and risk adjustments were derived from published

  1. Additives in yoghurt production

    Directory of Open Access Journals (Sweden)

    Milna Tudor

    2008-02-01

    Full Text Available In yoghurt production, mainly because of sensory characteristics, different types of additives are used. Each group, and also each substance from the same group has different characteristics and properties. For that reason, for improvement of yoghurt sensory characteristics apart from addition selection, the quantity of the additive is very important. The same substance added in optimal amount improves yoghurt sensory attributes, but too small or too big addition can reduce yoghurt sensory attributes. In this paper, characteristics and properties of mostly used additives in yoghurt production are described; skimmed milk powder, whey powder, concentrated whey powder, sugars and artificial sweeteners, fruits, stabilizers, casein powder, inulin and vitamins. Also the impact of each additive on sensory and physical properties of yoghurt, syneresis and viscosity, are described, depending on used amount added in yoghurt production.

  2. Electrodeposition of Al from a 1-butylpyrrolidine-AlCl3 ionic liquid

    Directory of Open Access Journals (Sweden)

    Giridhar Pulletikurthi

    2015-12-01

    Full Text Available The addition of 1-butylpyrrolidine to AlCl3 results in the formation of an electrolyte that is suited to Al deposition. The feasibility of electrodepositing Al from the synthesized electrolyte was investigated. Several compositions of AlCl3 and 1-butylpyrrolidine were prepared for this purpose. These mixtures show a different phase behavior at various compositions of AlCl3 and 1-butylpyrrolidine. IR, Raman and NMR spectroscopy were employed to characterize the synthesized liquids. Among the prepared compositions, 1:1.2 mol ratio of 1-butylpyrrolidine:AlCl3 and the upper phase of 1:1.3 mol ratio of 1-butylpyrrolidine:AlCl3 were found to be suitable for Al electrodeposition at room temperature (RT. Uniform and thick (~µm thick layers of Al were obtained on copper at RT. Al deposition occured from the cationic species of AlCl3−xLy+ (where x≤2, y=1–2, and L=1-butylpyrrolidine in this electrolyte. This behavior is contrary to the well investigated classic AlCl3 based ionic liquids, where the deposition of Al occurs mainly from anionic Al2Cl7− ions.

  3. /Cu-Al System

    Science.gov (United States)

    Kish, Orel; Froumin, Natalya; Aizenshtein, Michael; Frage, Nachum

    2014-05-01

    Wettability and interfacial interaction of the Ta2O5/Cu-Al system were studied. Pure Cu does not wet the Ta2O5 substrate, and improved spreading is achieved when relatively a high fraction of the active element (~40 at.% Al) was added. The Al2O3 and AlTaO4 phases were observed at the Ta2O5/Cu-Al interface. A thermodynamic evaluation allowed us to suggest that the lack of wetting bellow 40 at.% Al is due to the presence of a native oxide, which covers the drop. The conditions of the native oxide decomposition and the formation of the volatile Al2O suboxide strongly depend on the vacuum level during sessile drop experiments and the composition of the Cu-Al alloy. In our case, Al contents greater than 40% provides thermodynamic conditions for the formation of Al2O (as a result of Al reaction with Al2O3) and the drop spreading. It was suggested that the final contact angle in the Ta2O5/Cu-Al system (50°) is determined by Ta adsorption on the newly formed alumina interlayer.

  4. Polylactides in additive biomanufacturing.

    Science.gov (United States)

    Poh, Patrina S P; Chhaya, Mohit P; Wunner, Felix M; De-Juan-Pardo, Elena M; Schilling, Arndt F; Schantz, Jan-Thorsten; van Griensven, Martijn; Hutmacher, Dietmar W

    2016-12-15

    New advanced manufacturing technologies under the alias of additive biomanufacturing allow the design and fabrication of a range of products from pre-operative models, cutting guides and medical devices to scaffolds. The process of printing in 3 dimensions of cells, extracellular matrix (ECM) and biomaterials (bioinks, powders, etc.) to generate in vitro and/or in vivo tissue analogue structures has been termed bioprinting. To further advance in additive biomanufacturing, there are many aspects that we can learn from the wider additive manufacturing (AM) industry, which have progressed tremendously since its introduction into the manufacturing sector. First, this review gives an overview of additive manufacturing and both industry and academia efforts in addressing specific challenges in the AM technologies to drive toward AM-enabled industrial revolution. After which, considerations of poly(lactides) as a biomaterial in additive biomanufacturing are discussed. Challenges in wider additive biomanufacturing field are discussed in terms of (a) biomaterials; (b) computer-aided design, engineering and manufacturing; (c) AM and additive biomanufacturing printers hardware; and (d) system integration. Finally, the outlook for additive biomanufacturing was discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Bankole et al (2)

    African Journals Online (AJOL)

    DELL

    Relationships of Clay-filled Channels on the Delta Flanks (Modified after Doust and Omatsola, 1990 and Lawrence et al., 2002). ... and in the Indo-Malaysian area (Germeraad et al.,. 1968). The genus ..... Upper Cretaceous of British Guiana.

  6. Lou Gehrig's Disease (ALS)

    Science.gov (United States)

    ... disease. Who Gets ALS? Although this disease can strike anyone, ALS is extremely rare in kids. According ... home to provide care that the family cannot handle alone. Living With Lou Gehrig's Disease Living with ...

  7. Aussprache als motorische Fertigkeit

    DEFF Research Database (Denmark)

    Bonner, Maria

    2013-01-01

    Authentische Aussprache gilt im Fremdsprachenunterricht als schwer erreichbares Ziel, fremdsprachlicher Akzent wird als nahezu unvermeidbar gesehen. Weder die Hypothese einer kritischen Periode für den Erwerb einer authentischen Aussprache noch das Konzept der Fossilierung im Sprachlernprozess...

  8. SAP-like ultrafine-grained Al composites dispersion strengthened with nanometric AlN

    International Nuclear Information System (INIS)

    Balog, M.; Krizik, P.; Yan, M.; Simancik, F.; Schaffer, G.B.; Qian, M.

    2013-01-01

    This paper reports the development of novel Sinter-Aluminum-Pulver (SAP)-like Al–AlN nanocomposites via replacing the native Al 2 O 3 thin films on fine Al powder with a large volume fraction of in situ formed nanometric AlN dispersoids. Fine gas-atomized Al powder (d 50 =1.3 µm) compacts were first partially nitrided at 590 °C in flowing nitrogen, controlled by a small addition of Sn (0.3–0.4 wt%), and subsequently consolidated by hot direct extrusion. The resulting Al–AlN composites consisted of submicrometric Al grains reinforced with nanometric AlN dispersoids together with some nanometric Al 2 O 3 dispersoids. An Al–13 vol% AlN nanocomposite fabricated this way achieved exceptional ultimate tensile strength of 227 MPa, yield strength of 195 MPa and Young's modulus of 66 GPa at 300 °C, superior to typical SAP materials and coarse grained Al–AlN composites. In addition, the Al–13 vol% AlN nanocomposite exhibited good thermal stability up to 500 °C. The strengthening mechanism is discussed

  9. Neue Werkstoffe über additive Fertigung

    OpenAIRE

    Günther, Johannes; Niendorf, Thomas

    2016-01-01

    Über die additive Fertigung, oftmals bezeichnet als 3D-Druck, lassen sich Bauteile nahezu beliebiger geometrischer Komplexität herstellen. Gleichzeitig lassen die Prozessrandbedingungen die direkte Einstellung der Mikrostruktur in den verwendeten metallischen Werkstoffen zu. Hieraus ergeben sich weitreichende Möglichkeiten bezüglich der Eigenschaftsoptimierung aktueller Hochleistungswerkstoffe.

  10. Amyotrophic lateral sclerosis (ALS)

    Science.gov (United States)

    Lou Gehrig disease; ALS; Upper and lower motor neuron disease; Motor neuron disease ... One out of 10 cases of ALS is due to a genetic defect. The cause is unknown in most other cases. In ALS, motor nerve cells (neurons) waste away ...

  11. Additive and polynomial representations

    CERN Document Server

    Krantz, David H; Suppes, Patrick

    1971-01-01

    Additive and Polynomial Representations deals with major representation theorems in which the qualitative structure is reflected as some polynomial function of one or more numerical functions defined on the basic entities. Examples are additive expressions of a single measure (such as the probability of disjoint events being the sum of their probabilities), and additive expressions of two measures (such as the logarithm of momentum being the sum of log mass and log velocity terms). The book describes the three basic procedures of fundamental measurement as the mathematical pivot, as the utiliz

  12. Effect of elevated Al and pH on the growth and root morphology of Al-tolerant and Al-sensitive wheat seedlings in an acid soil

    Directory of Open Access Journals (Sweden)

    Md. Toufiq Iqbal

    2014-03-01

    Full Text Available Aluminium ion (Al3+ toxicity and hydrogen ion (H+ activity are the major constraints for plant growth in acid soil. This study was undertaken to determine the effect of pH and Al on the growth response and changes in root morphology of Al-tolerant (ET8 and Al-sensitive (ES8 wheat seedlings. Different levels of AlCl3 and CaCO3 were added to the soils to manipulate soil pH and extractable Al. The results showed that the bulk soil pH remained constant at pH 4.1 with further applications of AlCl3, and that the seedlings died at the 200 mg AlCl3/kg treatments. The ET8 seedlings responded better than the ES8 seedlings in both low and high Al and pH. The ET8 seedlings had higher root surface areas and root tip numbers than the ES8 seedlings in the Al treatment. In contrast, the ES8 had higher root diameters than the ET8 seedlings due to the elevated Al supply. Apoplast Al increased with the increase of soil available extractable Al, and declined with the decrease of soil extractable Al. The ET8 seedlings accumulated more Al in their apoplast than the ES8 seedlings. This study concluded that accumulation of Al in the apoplast is also involved in Al tolerance mechanism with the addition of organic acid exudation.

  13. Food Additives and Hyperkinesis

    Science.gov (United States)

    Wender, Ester H.

    1977-01-01

    The hypothesis that food additives are causally associated with hyperkinesis and learning disabilities in children is reviewed, and available data are summarized. Available from: American Medical Association 535 North Dearborn Street Chicago, Illinois 60610. (JG)

  14. Groups – Additive Notation

    Directory of Open Access Journals (Sweden)

    Coghetto Roland

    2015-06-01

    Full Text Available We translate the articles covering group theory already available in the Mizar Mathematical Library from multiplicative into additive notation. We adapt the works of Wojciech A. Trybulec [41, 42, 43] and Artur Korniłowicz [25].

  15. Groups – Additive Notation

    OpenAIRE

    Coghetto Roland

    2015-01-01

    We translate the articles covering group theory already available in the Mizar Mathematical Library from multiplicative into additive notation. We adapt the works of Wojciech A. Trybulec [41, 42, 43] and Artur Korniłowicz [25].

  16. Mechanochemical synthesis of dodecyl sulfate anion (DS-) intercalated Cu-Al layered double hydroxide

    Science.gov (United States)

    Qu, Jun; He, Xiaoman; Lei, Zhiwu; Zhang, Qiwu; Liu, Xinzhong

    2017-12-01

    Dodecyl sulfate anion (DS-) was successfully intercalated into the gallery space of Cu-Al layered double hydroxides (LDH) by a non-heating mechanochemical route, in which basic cupric carbonate (Cu2(OH)2CO3) and aluminum hydroxide (Al(OH)3) were first dry ground and then agitated in SDS solution under ambient environment. The organics modified Cu-Al LDH showed good adsorption ability toward 2,4-dichlorophenoxyacetic acid (2, 4-D). The prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), CHS elemental analysis and Scanning electron microscopy (SEM). The LDH precursor prepared by ball-milling could directly react with SDS molecules forming a pure phase of DS- pillared Cu-Al LDH, which was not observed with the LDH product through the ion-exchange of DS- at room temperature. The process introduced here may be applied to manufacture other types of organic modified composites for pollutants removal and other applications.

  17. 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.

  18. Protocol Additional to the Agreement between the Government of the Republic of Ghana and the International Atomic Energy Agency for the Application of Safeguards in connection with the Treaty on the Non-Proliferation of Nuclear Weapons; Protocolo Adicional Al Acuerdo Entre La Republica De Ghana Y El Organismo Internacional De Energia Atomica Para La Aplicacion De Salvaguardias En Relacion Con El Tratado Sobre La No Proliferacion De Las Armas Nucleares

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-11-27

    The text of the Protocol Additional to the Safeguards Agreement concluded between the Government of the Republic of Ghana and the International Atomic Energy Agency for the application of safeguards in connection with the Treaty for the Non-Proliferation of Nuclear Weapons (NPT) is reproduced in this document for the information of all Members. The Additional Protocol was approved by the Board of Governors on 11 June 1998. It was signed in Vienna on 12 June 1998 [Spanish] Se transcribe en el presente documento, para informacion de todos los Estados Miembros, el texto del Protocolo adicional al Acuerdo de salvaguardias concertado entre la Republica de Ghana y el Organismo Internacional de Energia Atomica para la aplicacion de salvaguardias en relacion con el Tratado sobre la no proliferacion de las armas nucleares (TNP). El Protocolo adicional fue aprobado por la Junta de Gobernadores el 11 de junio de 1998 y firmado en Viena el 12 de junio de 1998.

  19. Alternative additives; Alternative additiver

    Energy Technology Data Exchange (ETDEWEB)

    2007-08-15

    In this project a number of industrial and agricultural waste products have been characterised and evaluated in terms of alkali-getter performance. The intended use is for biomass-fired power stations aiming at reducing corrosion or slagging related problems. The following products have been obtained, characterised and evaluated: 1) Brewery draff 2) Danish de-gassed manure 3) Paper sludge 4) Moulding sand 5) Spent bleaching earth 6) Anorthosite 7) Sand 8) Clay-sludge. Most of the above alternative additive candidates are deemed unsuitable due to insufficient chemical effect and/or expensive requirements for pre-treatment (such as drying and transportation). 3 products were selected for full-scale testing: de-gassed manure, spent bleaching earth and clay slugde. The full scale tests were undertaken at the biomass-fired power stations in Koege, Slagelse and Ensted. Spent bleaching earth (SBE) and clay sludge were the only tested additive candidates that had a proven ability to react with KCl, to thereby reduce Cl-concentrations in deposits, and reduce the deposit flux to superheater tubes. Their performance was shown to nearly as good as commercial additives. De-gassed manure, however, did not evaluate positively due to inhibiting effects of Ca in the manure. Furthermore, de-gassed manure has a high concentration of heavy metals, which imposes a financial burden with regard to proper disposal of the ash by-products. Clay-sludge is a wet clay slurring, and drying and transportation of this product entails substantial costs. Spent bleaching does not require much pre-treatment and is therefore the most promising alternative additive. On the other hand, bleaching earth contains residual plant oil which means that a range of legislation relating to waste combustion comes into play. Not least a waste combustion fee of 330 DKK/tonne. For all alternative (and commercial) additives disposal costs of the increase ash by-products represents a significant cost. This is

  20. 143 - 148_Makeri et al.

    African Journals Online (AJOL)

    USER

    2015-06-01

    Jun 1, 2015 ... Yuan et al., 2003), antimicrobial activity (Sundarrao et al., 1993; Betancur-Galvis et al., 1999; Takashi et al., 2006), anti-parasitic, anti-malarial activities (Alali et al., 1998; Jaramillo et al., 2000; Luna et al.,. 2005). This study evaluates the antibacterial activity of extract of stem –bark and leaf extracts of Annona.

  1. Abu al-Layth al-Libi

    Science.gov (United States)

    2015-02-01

    success. As an Arab participant acknowledged very early on, “the situation was really harsh. All the brothers were tired,” as they lacked food and... glorious battles that occurred during the early Islamic period.133 He stressed the importance of the battlefield as the path to achieve honor and dignity...diaspora in Waziristan. In the words of Walid Othmani, a French jihadi trained by al-Qa`ida in Waziristan in 2008, “[Al-Libi] was someone well-known and

  2. Electronic Structures and Bonding Properties of Ti2AlC and Ti3AlC2

    Institute of Scientific and Technical Information of China (English)

    MIN Xinmin; REN Yi

    2007-01-01

    The relation among electronic structure, chemical bond and property of Ti2AlC, Ti3AlC2 and doping Si into Ti2AlC was studied by density function and the discrete variation (DFT-DVM) method. After adding Si into Ti2AlC, the interaction between Si and Ti is weaker than that between Al and Ti, and the strengths of ionic and covalent bonds decrease both. The ionic and covalent bonds in Ti3AlC2, especially in Ti-Al, are stronger than those in Ti2AlC. Therefore, in synthesis of Ti2AlC, the addition of Si enhances the Ti3AlC2 content instead of Ti2AlC. The density of state (DOS) shows that there is mixed conductor characteristic in Ti2AlC and Ti3AlC2. The DOS of Ti3AlC2 is much like that of Ti2AlC. Ti2SixAl1-x C has more obvious tendency to form a semiconductor than Ti2AlC, which is seen from the obvious difference of partial DOS between Si and Al3p.

  3. Precursor preparation for Ca-Al layered double hydroxide to remove hexavalent chromium coexisting with calcium and magnesium chlorides

    Science.gov (United States)

    Zhong, Lihua; He, Xiaoman; Qu, Jun; Li, Xuewei; Lei, Zhiwu; Zhang, Qiwu; Liu, Xinzhong

    2017-01-01

    Al(OH)3 and Ca(OH)2 powders are co-ground to prepare a precursor which hydrates into a layered double hydroxide (LDH) phase by agitation in aqueous solution with target hexavalent chromium (Cr(VI)) at room temperature, to achieve an obvious improvement in removal efficiency of Cr(VI) through an easy incorporation into the structure. Although the prepared precursor transforms into LDH phases also when agitated in the solutions of calcium and magnesium chlorides, it incorporates Cr(VI) preferentially to the chloride salts when they coexist. The adsorption isotherm and kinetic studies show that the phenomena occurring on the Al-Ca precursor fit a pseudo-second-order kinetics with a Langmuir adsorption capacity of 59.45 mg/g. Besides, characterizations of the prepared precursor and the samples after adsorption are also performed by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Transmission electron microscope (TEM) to understand the reason of the preferential incorporation of Cr(VI) to the coexisting chloride salts during the LDH phase formation. Ca-Al precursor (C3A) was agitated in a hexavalent chromium (Cr(VI)) solution to form Al-Ca-CrO4 LDH product. Ca-Al-CrO4 LDH phase occurred preferentially to Ca-Al-MCl2 LDH phases in the solutions of calcium and magnesium chlorides, it incorporates Cr(VI) preferentially to the chloride salts when they coexist.

  4. Interfacial Microstructure and Properties of Steel/Aluminum Powder Additive

    Directory of Open Access Journals (Sweden)

    YUAN Jiang

    2017-09-01

    Full Text Available Based on first-principles density functional theory, the Fe/Al interface model of steel/aluminum laser welding was constructed by layer technique. The Fe/Al interface was studied by metal atom X (X=Sn, Sr, Zr, Ce, La.The results show that Sn, Sr and Ce preferentially displace the Al atoms at the Fe/Al interface, while La and Zr preferentially displace the Fe atoms at the Fe/Al interface. Alloying promotes the transfer of Fe/Al interfacial electrons between different orbits, enhances the ionic bond properties of Fe-Al, improves the Fe/Al interface binding capacity, improves the brittle fracture of Fe/Al interface, and the alloying effect of Sn most notable. On the basis of this, the laser lap welding test of Sn and Zr powder was carried out on 1.4mm thick DC51D+ZF galvanized steel and 1.2mm thick 6016 aluminum alloy specimen. The results show that the addition of powder can promote the flowability of the molten bath and change the composition and microstructure of the joint interface. The tensile strength of the steel/aluminum joint is 327.41MPa and the elongation is 22.93% with the addition of Sn powder, which is obviously improved compared with the addition of Zr powder and without the addition of powder.

  5. Model Additional Protocol

    International Nuclear Information System (INIS)

    Rockwood, Laura

    2001-01-01

    Since the end of the cold war a series of events has changed the circumstances and requirements of the safeguards system. The discovery of a clandestine nuclear weapons program in Iraq, the continuing difficulty in verifying the initial report of Democratic People's Republic of Korea upon entry into force of their safeguards agreement, and the decision of the South African Government to give up its nuclear weapons program and join the Treaty on the Non-Proliferation of Nuclear Weapons have all played a role in an ambitious effort by IAEA Member States and the Secretariat to strengthen the safeguards system. A major milestone in this effort was reached in May 1997 when the IAEA Board of Governors approved a Model Protocol Additional to Safeguards Agreements. The Model Additional Protocol was negotiated over a period of less than a year by an open-ended committee of the Board involving some 70 Member States and two regional inspectorates. The IAEA is now in the process of negotiating additional protocols, State by State, and implementing them. These additional protocols will provide the IAEA with rights of access to information about all activities related to the use of nuclear material in States with comprehensive safeguards agreements and greatly expanded physical access for IAEA inspectors to confirm or verify this information. In conjunction with this, the IAEA is working on the integration of these measures with those provided for in comprehensive safeguards agreements, with a view to maximizing the effectiveness and efficiency, within available resources, the implementation of safeguards. Details concerning the Model Additional Protocol are given. (author)

  6. Characterization of the alteration products formed at the surface of LaYSiAlO and CeYSiAlO glasses using ERDA and RBS techniques

    International Nuclear Information System (INIS)

    Gavarini, S.; Trocellier, P.; Matzen, G.

    2004-01-01

    Leaching tests have been performed on LnYSiAlO glasses (Ln = La or Ce) that are considered as potential matrices for the specific immobilization of minor actinides. Elastic recoil detection analysis (ERDA) performed on leached samples indicated a superficial hydration of LaYSiAlO glass of about 100-150 nm. This hydrated layer is (Al, Y)-enriched according to SEM-EDS analysis, suggesting the formation of hydroxide (or hydroxycarbonates) compounds including these two elements. This process leads to a very efficient passivation of the material due to the low solubility of Al and Y hydroxides (and hydroxycarbonates) species in near neutral media, even when the solution is rapidly replenished is dynamic leaching experiments. Rutherford Backscattering Spectrometry elemental mapping revealed very localized and significantly Y-enriched deposits at the surface of the sample after leaching. This could be the sign of heterogeneities already present on the pristine glass. These may be correlated with the weak solubility of yttrium (and rare earth) elements in silicate matrices (Y + Ln initial content in the glass ∼11 at.%). In the case of CeYSiAlO glass, a thin layer was formed on the solid after leaching. The simulation of the corresponding RBS spectra showed a surface (Y, Ce)-enrichment and (Al, Si)-depletion in both cases. This could be explained by the oxidation of trivalent cerium initially present in the glass structure during leaching. This might be explained by the low solubility of Ce(IV)-compounds (CeO 2 and/or Ce(OH) 4 ) in solution leading to an enrichment of this element at the glass/solution interface, to form a mixture of amorphous CeO 2 and Y(OH) 3 , as confirmed by XPS and XRD experiments

  7. Phase constituents and microstructure of laser cladding Al2O3/Ti3Al reinforced ceramic layer on titanium alloy

    International Nuclear Information System (INIS)

    Li Jianing; Chen Chuanzhong; Lin Zhaoqing; Squartini, Tiziano

    2011-01-01

    Research highlights: → In this study, Fe 3 Al has been chosen as cladding powder due to its excellent properties of wear resistance and high strength, etc. → Laser cladding of Fe 3 Al + TiB 2 /Al 2 O 3 pre-placed alloy powder on Ti-6Al-4V alloy substrate can form the Ti 3 Al/Fe 3 Al + TiB 2 /Al 2 O 3 ceramic layer, which can increase wear resistance of substrate. → In cladding process, Al 2 O 3 can react with TiB 2 leading to formation of Ti 3 Al and B. → This principle can be used to improve the Fe 3 Al + TiB 2 laser-cladded coating. - Abstract: Laser cladding of the Fe 3 Al + TiB 2 /Al 2 O 3 pre-placed alloy powder on Ti-6Al-4V alloy can form the Ti 3 Al/Fe 3 Al + TiB 2 /Al 2 O 3 ceramic layer, which can greatly increase wear resistance of titanium alloy. In this study, the Ti 3 Al/Fe 3 Al + TiB 2 /Al 2 O 3 ceramic layer has been researched by means of electron probe, X-ray diffraction, scanning electron microscope and micro-analyzer. In cladding process, Al 2 O 3 can react with TiB 2 leading to formation of amount of Ti 3 Al and B. This principle can be used to improve the Fe 3 Al + TiB 2 laser cladded coating, it was found that with addition of Al 2 O 3 , the microstructure performance and micro-hardness of the coating was obviously improved due to the action of the Al-Ti-B system and hard phases.

  8. Pornographie als Metapher

    Directory of Open Access Journals (Sweden)

    Caroline Schubarth

    2010-02-01

    Full Text Available In diesem Artikel werden unterschiedliche metaphorische Verwendungen des Pornografiebegriffs und deren Implikationen untersucht. Während die Existenz von Pornografie der feministischen Anti-Porno-Bewegung als Erklärung für die anhaltende Diskriminierung von Frauen in westlichen Gesellschaften dient, nutzen rechtskonservative Kräfte den Pornografievorwurf als Rechtfertigung für die Zensur von als deviant empfundenen Identitäten und sexuellen Praktiken.

  9. The effect of H2O gas on volatilities of planet-forming major elements. I - Experimental determination of thermodynamic properties of Ca-, Al-, and Si-hydroxide gas molecules and its application to the solar nebula

    Science.gov (United States)

    Hashimoto, Akihiko

    1992-01-01

    The vapor pressures of Ca(OH)2(g), Al(OH)3(g), and Si(OH)4(g) molecules in equilibrium with solid calcium-, aluminum, and silicon-oxides, respectively, were determined, and were used to derive the heats of formation and entropies of these species, which are expected to be abundant under the currently postulated physical conditions in the primordial solar nebula. These data, in conjunction with thermodynamic data from literature, were used to calculate the relative abundances of M, MO(x), and M(OH)n gas species and relative volatilities of Fe, Mg, Si, Ca, and Al for ranges of temperature, total pressure, and H/O abundance ratio corresponding to the plausible ranges of physical conditions in the solar nebula. The results are used to explain how Ca and Al could have evaporated from Ca,Al-rich inclusions in carbonaceous chondrites, while Si, Mg, and Fe condensed onto them during the preaccretion alteration of CAIs.

  10. Some aspects of anelastic and microplastic creep of pure Al and two Al-alloys

    International Nuclear Information System (INIS)

    Sgobba, S.; Kuenzi, H.U.; Ilschner, B.

    1993-01-01

    Anelastic creep of pure Al, commercial Al-Cu and a binary Al-Cu alloy has been measured at room temperature by means of a high resolution laser interferometer. The irreversible component of the deformation was also quantified from measurements of the anelastic creep recovery. The dependence of the deformation-time curves on thermal treatment and cold work is analyzed. The mechanisms responsible for the room temperature anelastic creep are discussed. Materials loaded below their elastic limit can present either a pure anelastic behavior (commercial Al-Cu) or additional viscoelastic creep (pure Al, high purity Al-Cu). For commercial Al-Cu, the presence of an irreversible deformation appears to be mainly related to the state of the surface. A viscoelastic after effect has been measured for this alloy after a Cu-electroplating treatment. As a typical result for room temperature creep, the irreversible deformation depends logarithmically on load time. (orig.)

  11. Some aspects of anelastic and microplastic creep of pure Al and two Al-alloys

    Energy Technology Data Exchange (ETDEWEB)

    Sgobba, S. (Lab. de Metallurgie Mecanique, Dept. des Materiaux, Ecole Polytechnique Federale de Lausanne (Switzerland)); Kuenzi, H.U. (Lab. de Metallurgie Mecanique, Dept. des Materiaux, Ecole Polytechnique Federale de Lausanne (Switzerland)); Ilschner, B. (Lab. de Metallurgie Mecanique, Dept. des Materiaux, Ecole Polytechnique Federale de Lausanne (Switzerland))

    1993-11-01

    Anelastic creep of pure Al, commercial Al-Cu and a binary Al-Cu alloy has been measured at room temperature by means of a high resolution laser interferometer. The irreversible component of the deformation was also quantified from measurements of the anelastic creep recovery. The dependence of the deformation-time curves on thermal treatment and cold work is analyzed. The mechanisms responsible for the room temperature anelastic creep are discussed. Materials loaded below their elastic limit can present either a pure anelastic behavior (commercial Al-Cu) or additional viscoelastic creep (pure Al, high purity Al-Cu). For commercial Al-Cu, the presence of an irreversible deformation appears to be mainly related to the state of the surface. A viscoelastic after effect has been measured for this alloy after a Cu-electroplating treatment. As a typical result for room temperature creep, the irreversible deformation depends logarithmically on load time. (orig.).

  12. Additive manufacturing of metals

    International Nuclear Information System (INIS)

    Herzog, Dirk; Seyda, Vanessa; Wycisk, Eric; Emmelmann, Claus

    2016-01-01

    Additive Manufacturing (AM), the layer-by layer build-up of parts, has lately become an option for serial production. Today, several metallic materials including the important engineering materials steel, aluminium and titanium may be processed to full dense parts with outstanding properties. In this context, the present overview article describes the complex relationship between AM processes, microstructure and resulting properties for metals. It explains the fundamentals of Laser Beam Melting, Electron Beam Melting and Laser Metal Deposition, and introduces the commercially available materials for the different processes. Thereafter, typical microstructures for additively manufactured steel, aluminium and titanium are presented. Special attention is paid to AM specific grain structures, resulting from the complex thermal cycle and high cooling rates. The properties evolving as a consequence of the microstructure are elaborated under static and dynamic loading. According to these properties, typical applications are presented for the materials and methods for conclusion.

  13. Additive manufactured serialization

    Science.gov (United States)

    Bobbitt, III, John T.

    2017-04-18

    Methods for forming an identifying mark in a structure are described. The method is used in conjunction with an additive manufacturing method and includes the alteration of a process parameter during the manufacturing process. The method can form in a unique identifying mark within or on the surface of a structure that is virtually impossible to be replicated. Methods can provide a high level of confidence that the identifying mark will remain unaltered on the formed structure.

  14. Al-Âyah al-Mutasyâbihât al-Lafzhiyyah fi Sûrah al-An’âm ‘Inda al-Kirmâny

    Directory of Open Access Journals (Sweden)

    Hikmatiar Pasya

    2017-07-01

    Full Text Available This paper discusses about the verses of mutasyâbihât in the Quran. The debate of this verses caused various opinions. The meaning of the mutasyâbihât in this paper is the similarity and difference of the words in the Qur'an. Mufasir have different opinion about the meaning of the verse of mutasyâbihât al-lafdzi. In addition, many Hufadz of the Quran who are confused from one verse to another, or one chapter to another. It’s because similarity of verses in the Qur'an with other verses. So the writer wants to explain the verses mutasyâbihât al-lafdzi in the perspective of Hamzh al-Karmani in Surah al-An'âm. In this discussion the author discovers some passages in mutasyâbihât al-lafdzi, namely Asrâru al-balaghah fi mutasyabih al-lafdzi, Asrar al-balaghah fi mutasyabih al-hurf, and murâ'ah al-ikhtilâfmurâd bi al-lafdzi al-mukarrar.

  15. Direct observations of grain boundary phenomena during indentation of Al and Al-Mg thin films

    NARCIS (Netherlands)

    Soer, WA; De Hosson, JTM; Minor, AM; Stach, EA; Morris, Joan K.; Corcoran, SG; Joo, YC; Moody, NR; Suo, Z

    2004-01-01

    The deformation behaviour of Al and Al-Mg thin films has been studied with the unique experimental approach of in-situ nanoindentation in a transmission electron microscope. This paper concentrates on the role of solute Mg additions in the transfer of plasticity across grain boundaries. The

  16. Alles is al uitgevonden

    NARCIS (Netherlands)

    J.G.M. van Marrewijk (Charles)

    1996-01-01

    textabstractDe voordelen van vrijhandel zijn zeer beperkt, al-thans als we de empirische schattingen van vooraanstaande economen en internationale organisaties mogen geloven. Zo worden de voordelen van liberalisatie voor de Europese Unie geraamd op ongeveer 0,5% van het bnp 1. De door het IMF

  17. Lukman et al. (5)

    African Journals Online (AJOL)

    DELL

    1 Civil Engineering Department, Obafemi Awolowo University, Ile-Ife- Nigeria and Corresponding author. 2Department of Water Resources and Environmental Engineering, Ahmadu Bello University, Samaru, Zaria- Nigeria s Department of Civil Engineering, University of Hafr Al-Batin, Hafr Al-Batin, Saudi Arabia.

  18. BWR zinc addition Sourcebook

    International Nuclear Information System (INIS)

    Garcia, Susan E.; Giannelli, Joseph F.; Jarvis, Alfred J.

    2014-01-01

    Boiling Water Reactors (BWRs) have been injecting zinc into the primary coolant via the reactor feedwater system for over 25 years for the purpose of controlling primary system radiation fields. The BWR zinc injection process has evolved since the initial application at the Hope Creek Nuclear Station in 1986. Key transitions were from the original natural zinc oxide (NZO) to depleted zinc oxide (DZO), and from active zinc injection of a powdered zinc oxide slurry (pumped systems) to passive injection systems (zinc pellet beds). Zinc addition has continued through various chemistry regimes changes, from normal water chemistry (NWC) to hydrogen water chemistry (HWC) and HWC with noble metals (NobleChem™) for mitigation of intergranular stress corrosion cracking (IGSCC) of reactor internals and primary system piping. While past reports published by the Electric Power Research Institute (EPRI) document specific industry experience related to these topics, the Zinc Sourcebook was prepared to consolidate all of the experience gained over the past 25 years. The Zinc Sourcebook will benefit experienced BWR Chemistry, Operations, Radiation Protection and Engineering personnel as well as new people entering the nuclear power industry. While all North American BWRs implement feedwater zinc injection, a number of other BWRs do not inject zinc. This Sourcebook will also be a valuable resource to plants considering the benefits of zinc addition process implementation, and to gain insights on industry experience related to zinc process control and best practices. This paper presents some of the highlights from the Sourcebook. (author)

  19. Interview als Text vs. Interview als Interaktion

    Directory of Open Access Journals (Sweden)

    Arnulf Deppermann

    2013-09-01

    Full Text Available Das Interview ist nach wie vor das beliebteste sozialwissenschaftliche Verfahren des Datengewinns. Ökonomie der Erhebung, Vergleichbarkeit und die Möglichkeit, Einsicht in Praxisbereiche und historisch-biografische Dimensionen zu erhalten, die der direkten Beobachtung kaum zugänglich sind, machen seine Attraktivität aus. Zugleich mehren sich Kritiken, die seine Leistungsfähigkeit problematisieren, indem sie auf die begrenzte Reichweite der Explikationsfähigkeiten der Befragten, die Reaktivität der Erhebung oder die Differenz zwischen Handeln und dem Bericht über Handeln verweisen. Im Beitrag wird zwischen Ansätzen, die das Interview als Text, und solchen, die es als Interaktion verstehen, unterschieden. Nach dem Text-Verständnis werden Interviews unter inhaltlichen Gesichtspunkten analysiert und als Zugang zu einer vorgängigen sozialen oder psychischen Wirklichkeit angesehen. Das Interaktions-Verständnis versteht Interviews dagegen als situierte Praxis, in welcher im Hier und Jetzt von InterviewerInnen und Befragten gemeinsam soziale Sinnstrukturen hergestellt werden. Anhand ubiquitärer Phänomene der Interviewinteraktion – Fragen, Antworten und die Selbstpositionierung von InterviewerInnen und Befragten – werden Praktiken des interaktiv-performativen Handelns im Interview dargestellt. Ihre Relevanz für die Interviewkonstitution und ihre Erkenntnispotenziale für die Interviewauswertung werden aufgezeigt. Es wird dafür plädiert, die interaktive Konstitutionsweise von Interviews empirisch zu erforschen und methodisch konsequent zu berücksichtigen. URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs1303131

  20. Effects of sulphur addition on modification and mechanical ...

    African Journals Online (AJOL)

    CW Onyia, BA Okorie, NI Amalu, SI Neife ... The results showed that the addition of sulphur to Al-12wt%Si alloy modified the Al-Si eutectic ... of the eutectic silicon structure with significant decrease in mechanical properties of the alloy and this ...

  1. ATXN2 trinucleotide repeat length correlates with risk of ALS

    NARCIS (Netherlands)

    Sproviero, William; Shatunov, Aleksey; Stahl, Daniel; Shoai, Maryam; van Rheenen, Wouter; Jones, Ashley R; Al-Sarraj, Safa; Andersen, Peter M.; Bonini, Nancy M; Conforti, Francesca L; Van Damme, Philip; Daoud, Hussein; Del Mar Amador, Maria; Fogh, Isabella; Forzan, Monica; Gaastra, Ben; Gellera, Cinzia; Gitler, Aaron D; Hardy, John; Fratta, Pietro; La Bella, Vincenzo; Le Ber, Isabelle; Van Langenhove, Tim; Lattante, Serena; Lee, Yi-Chung; Malaspina, Andrea; Meininger, Vincent; Millecamps, Stéphanie; Orrell, Richard W; Rademakers, Rosa; Robberecht, Wim; Rouleau, Guy A.; Ross, Owen A; Salachas, Francois; Sidle, Katie; Smith, Bradley N; Soong, Bing-Wen; Sorarù, Gianni; Stevanin, Giovanni; Kabashi, Edor; Troakes, Claire; van Broeckhoven, Christine; Veldink, Jan H.; van den Berg, Leonard H.; Shaw, Christopher E; Powell, John F.; Al-Chalabi, Ammar

    2017-01-01

    We investigated a CAG trinucleotide repeat expansion in the ATXN2 gene in amyotrophic lateral sclerosis (ALS). Two new case-control studies, a British dataset of 1474 ALS cases and 567 controls, and a Dutch dataset of 1328 ALS cases and 691 controls were analyzed. In addition, to increase power, we

  2. Dynamics of ultrasonic additive manufacturing.

    Science.gov (United States)

    Hehr, Adam; Dapino, Marcelo J

    2017-01-01

    Ultrasonic additive manufacturing (UAM) is a solid-state technology for joining similar and dissimilar metal foils near room temperature by scrubbing them together with ultrasonic vibrations under pressure. Structural dynamics of the welding assembly and work piece influence how energy is transferred during the process and ultimately, part quality. To understand the effect of structural dynamics during UAM, a linear time-invariant model is proposed to relate the inputs of shear force and electric current to resultant welder velocity and voltage. Measured frequency response and operating performance of the welder under no load is used to identify model parameters. Using this model and in-situ measurements, shear force and welder efficiency are estimated to be near 2000N and 80% when welding Al 6061-H18 weld foil, respectively. Shear force and welder efficiency have never been estimated before in UAM. The influence of processing conditions, i.e., welder amplitude, normal force, and weld speed, on shear force and welder efficiency are investigated. Welder velocity was found to strongly influence the shear force magnitude and efficiency while normal force and weld speed showed little to no influence. The proposed model is used to describe high frequency harmonic content in the velocity response of the welder during welding operations and coupling of the UAM build with the welder. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Dimensionless numbers in additive manufacturing

    Science.gov (United States)

    Mukherjee, T.; Manvatkar, V.; De, A.; DebRoy, T.

    2017-02-01

    The effects of many process variables and alloy properties on the structure and properties of additively manufactured parts are examined using four dimensionless numbers. The structure and properties of components made from 316 Stainless steel, Ti-6Al-4V, and Inconel 718 powders for various dimensionless heat inputs, Peclet numbers, Marangoni numbers, and Fourier numbers are studied. Temperature fields, cooling rates, solidification parameters, lack of fusion defects, and thermal strains are examined using a well-tested three-dimensional transient heat transfer and fluid flow model. The results show that lack of fusion defects in the fabricated parts can be minimized by strengthening interlayer bonding using high values of dimensionless heat input. The formation of harmful intermetallics such as laves phases in Inconel 718 can be suppressed using low heat input that results in a small molten pool, a steep temperature gradient, and a fast cooling rate. Improved interlayer bonding can be achieved at high Marangoni numbers, which results in vigorous circulation of liquid metal, larger pool dimensions, and greater depth of penetration. A high Fourier number ensures rapid cooling, low thermal distortion, and a high ratio of temperature gradient to the solidification growth rate with a greater tendency of plane front solidification.

  4. Preparation of Pd/γ- Al2O3 catalyst utilized in chemisorption of hydrogen isotopes

    International Nuclear Information System (INIS)

    David, Elena; Stefanescu, Doina; Stanciu, V.

    1997-01-01

    Separation and hydrogen isotope determination require packings with special properties, utilizable in separation columns. Consequently, such packings as catalysts using γ-aluminia and metallic palladium active component as holder were obtained. The γ-aluminia used as holder has been prepared starting from λ salts, easy soluble in water, such as Al 2 (NO 3 ) 3 ·9H 2 O, at a preset (6.2-6.4) controlled pH. At a first stage the Al(OH) 3 results which by calcination at controlled temperature transforms in γ-Al 2O3 . On this holder, in which the specific surface and porosity has been determined, metallic palladium has been deposed, using for impregnation a 2% PdCl 2 solution. The content of deposed palladium was determined as the difference between the content in the initial solution and solution remaining after holder impregnation. This content has been determined by atomic absorption and is within 0.5 - 1.2% Pd. After impregnation the catalyst has been dried, then granulated at the 0.16 mm size and activated by hydrogen at a flow rate of 300 vol H 2 /volume

  5. Teardrop bladder: additional considerations

    International Nuclear Information System (INIS)

    Wechsler, R.J.; Brennan, R.E.

    1982-01-01

    Nine cases of teardrop bladder (TDB) seen at excretory urography are presented. In some of these patients, the iliopsoas muscles were at the upper limit of normal in size, and additional evaluation of the perivesical structures with computed tomography (CT) was necessary. CT demonstrated only hypertrophied muscles with or without perivesical fat. The psoas muscles and pelvic width were measured in 8 patients and compared with the measurements of a control group of males without TDB. Patients with TDB had large iliopsoas muscles and narrow pelves compared with the control group. The psoas muscle width/pelvic width ratio was significantly greater (p < 0.0005) in patients with TDB than in the control group, with values of 1.04 + 0.05 and 0.82 + 0.09, respectively. It is concluded that TDB is not an uncommon normal variant in black males. Both iliopsoas muscle hypertrophy and a narrow pelvis are factors that predispose a patient to TDB

  6. Sewage sludge additive

    Science.gov (United States)

    Kalvinskas, J. J.; Mueller, W. A.; Ingham, J. D. (Inventor)

    1980-01-01

    The additive is for a raw sewage treatment process of the type where settling tanks are used for the purpose of permitting the suspended matter in the raw sewage to be settled as well as to permit adsorption of the dissolved contaminants in the water of the sewage. The sludge, which settles down to the bottom of the settling tank is extracted, pyrolyzed and activated to form activated carbon and ash which is mixed with the sewage prior to its introduction into the settling tank. The sludge does not provide all of the activated carbon and ash required for adequate treatment of the raw sewage. It is necessary to add carbon to the process and instead of expensive commercial carbon, coal is used to provide the carbon supplement.

  7. Study of plutonium-addition systems

    International Nuclear Information System (INIS)

    Kuchar, L.; Wozniakova, B.

    1976-11-01

    Steady state phase diagrams and calculated values of concentrations on the solid and liquid curves, the steady state distribution coefficient and thermodynamic control are presented for temperatures ranging from the eutectic reaction temperatures to the Pu melting point temperature for binary systems plutonium-addition (Mg, Al, Si, Ti, Mn, Fe, Co, Ni, Cu, Zn, Ga, Zr, Ru, Os, Th, U, Np). (J.P.)

  8. Blistering in ALD Al2O3 passivation layers as rear contacting for local Al BSF Si solar cells

    NARCIS (Netherlands)

    Vermang, B.; Goverde, J.C.; Uruena, A.; Lorenz, A.; Cornagliotti, E.; Rothschild, A.; John, J.; Poortmans, J.; Mertens, R.

    2012-01-01

    Random Al back surface field (BSF) p-type Si solar cells are presented, where a stack of Al2O3 and SiNx is used as rear surface passivation layer containing blisters. It is shown that no additional contact opening step is needed, since during co-firing local Al BSFs are induced at the location of

  9. Microstructure and properties of Mg-Al binary alloys

    Directory of Open Access Journals (Sweden)

    ZHENG Wei-chao

    2006-11-01

    Full Text Available The effects of different amounts of added Al, ranging from 1 % to 9 %, on the microstructure and properties of Mg-Al binary alloys were investigated. The results showed that when the amount of added Al is less than 5%, the grain size of the Mg-Al binary alloys decreases dramatically from 3 097 μm to 151 μm with increasing addition of Al. Further addition of Al up to 9% makes the grain size decrease slowly to 111 μm. The α-Mg dendrite arms are also refined. Increasing the amount of added Al decreases the hot cracking susceptibility of the Mg-Al binary alloys remarkably, and enhances the micro-hardness of the α-Mg matrix.

  10. Universitat popular al Cabanyal

    OpenAIRE

    Ribés Granell, Juan Miguel

    2012-01-01

    La intención es dotar al barrio de un gran espacio verde y de un edificio de interés para los vecinos que enriquezca al Cabanyal, ya que actualmente se encuentra en proceso de degradación. Se pretende desarrollar un proyecto que signifique una mejora en la predisposición del visitante, cubriendo sus necesidades. Al mismo tiempo, se busca crear un espacio arquitectónico que mejore la relación entre las actividades que incluye y su entorno. El proyecto está condicionado por cuatro aspectos fund...

  11. Additive lattice kirigami.

    Science.gov (United States)

    Castle, Toen; Sussman, Daniel M; Tanis, Michael; Kamien, Randall D

    2016-09-01

    Kirigami uses bending, folding, cutting, and pasting to create complex three-dimensional (3D) structures from a flat sheet. In the case of lattice kirigami, this cutting and rejoining introduces defects into an underlying 2D lattice in the form of points of nonzero Gaussian curvature. A set of simple rules was previously used to generate a wide variety of stepped structures; we now pare back these rules to their minimum. This allows us to describe a set of techniques that unify a wide variety of cut-and-paste actions under the rubric of lattice kirigami, including adding new material and rejoining material across arbitrary cuts in the sheet. We also explore the use of more complex lattices and the different structures that consequently arise. Regardless of the choice of lattice, creating complex structures may require multiple overlapping kirigami cuts, where subsequent cuts are not performed on a locally flat lattice. Our additive kirigami method describes such cuts, providing a simple methodology and a set of techniques to build a huge variety of complex 3D shapes.

  12. Grain refinement of cast titanium alloys via trace boron addition

    International Nuclear Information System (INIS)

    Tamirisakandala, S.; Bhat, R.B.; Tiley, J.S.; Miracle, D.B.

    2005-01-01

    The grain size of as-cast Ti-6Al-4V is reduced by about an order of magnitude from 1700 to 200 μm with an addition of 0.1 wt.% boron. A much weaker dependence of reduction in grain size is obtained for boron additions from >0.1% to 1.0%. Similar trends were observed in boron-modified as-cast Ti-6Al-2Sn-4Zr-2Mo-0.1Si

  13. Effect of Al and AlP on the microstructure of Mn-30 wt.%Si alloy

    Energy Technology Data Exchange (ETDEWEB)

    Wu Yuying [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jing Shi Road 73, Jinan 250061 (China); Liu Xiangfa [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jing Shi Road 73, Jinan 250061 (China)], E-mail: xfliu@sdu.edu.cn

    2008-04-15

    Effect of Al and AlP particles on the microstructure of near eutectic Mn-Si alloy (Mn-30 wt.%Si) was studied by Electron Probe Micro-analyzer (EPMA) and Differential Scanning Calorimeter (DSC). Crystal lattice correspondence analyses show that both Al and AlP have good lattice matching coherence relationships with MnSi phase, and the addition of Al and AlP particles results in an abnormal eutectic structure, i.e. the eutectic constitution MnSi and Mn{sub 5}Si{sub 3} precipitate separately: MnSi precipitates firstly, and then the Mn{sub 5}Si{sub 3} phase.

  14. Alpha and beta stabilizer character of Al in Zr-Nb-Al alloys

    International Nuclear Information System (INIS)

    Peruzzi Bardella, A.; Bolcich, J.C.

    1987-01-01

    The T β/α+β of Zr5Nb and Zr5Nb2Al (weight %) were determined in order to observe the alpha-stabilizer character of Al in ternary Zr-Nb-Al alloys. Techniques employed were change of resistivity with temperature in dynamic experiences, and metallography of samples quenched to room temperature after isothermal annealings. The T β/α+β of the ternary resulted 17 ± 8 deg C higher than that of the binary alloy. In addition, taking into account the results of previous investigations of the transformation of beta on quenching Zr-Nb-Al alloys from the beta field to room temperature, it is concluded that the beta-stabilizer character of Nb is stronger than the alpha-stabilizer character of Al in these Zr alloys, and that the Al can have important influence on the mechanical properties by the appearance of TRIP effect. (Author) [es

  15. Coste-efectividad de la adición de acarbosa al tratamiento de pacientes con diabetes tipo 2 en España Cost-effectiveness of the addition of acarbose to the treatment of patients with type-2 diabetes in Spain

    OpenAIRE

    Carme Piñol; Stephane Roze; William Valentine; Thomas Evers

    2007-01-01

    Objetivos: Evaluar el coste-efectividad de la adición de acarbosa al tratamiento de pacientes con diabetes mellitus tipo 2 (DM2) en España. Métodos: Se utilizó el CORE Diabetes Model (modelo de simulación informática publicado y validado) para proyectar a largo plazo los resultados clínicos y de costes de la DM2. Las probabilidades de transición y los riesgos se obtuvieron de distintas publicaciones. Los efectos del tratamiento y las características basales de la cohorte se obtuvieron de un m...

  16. Advanced Light Source (ALS)

    Data.gov (United States)

    Federal Laboratory Consortium — The Advanced Light Source (ALS), a world leader in soft x-ray science, generates light in the wavelengths needed for examining the atomic and electronic structure of...

  17. Taiwo et al (15)

    African Journals Online (AJOL)

    Timothy Ademakinwa

    geometric rise in preference for commercial aquaculture .... content, malondialdehyde level and lipid content of the muscle of the .... other researchers on the gilthead sea bream (Mnari et al., 2007), the .... 23, Orlando, Florida, USA, pp. 18–28.

  18. Okusanya et al (5)

    African Journals Online (AJOL)

    DELL

    rainfall and number of days with rain per month were obtained from Meteorological Institute, Oshodi, Lagos- ... Central and South America, Australia, West. Indies, Africa, (Orwa et al., 2009) and in Florida .... dominant forest tree species. In this ...

  19. Initial Symptoms of ALS

    Science.gov (United States)

    ... have trouble grasping a pen or lifting a coffee cup, while another person may experience a change ... Start your own fundraising event & help create a world without ALS Start an Event Site Map | Press ...

  20. ALS (Amyotrophic Lateral Sclerosis)

    Science.gov (United States)

    ... FDA) has approved the drugs riluzole (Rilutek) and edaravone (Radicava) to treat ALS. Riluzole is believed to ... reverse the damage already done to motor neurons. Edaravone has been shown to slow the decline in ...

  1. Amyotrophic Lateral Sclerosis (ALS)

    Science.gov (United States)

    ... found for ALS. However, the drugs riluzole and edaravone have approved by the Food and Drug Administration ( ... 2-3 months but does not relieve symptoms. Edaravone can slow the clinical decline in daily functioning ...

  2. Obuotor et al (16)

    African Journals Online (AJOL)

    DELL

    fractions and essential oils from the leaves of Eugenia uniflora were investigated on some multidrug resistant pathogens. ... et al., 1987), a reduction in blood pressure measured ..... from E. uniflora suggests high efficacy against this bacterium.

  3. Fakinle et al (11)

    African Journals Online (AJOL)

    DELL

    management issues; there is however a concern about air emissions from the ... poses risks to humans and animals through ... Nigeria have focused on cement industries. (Adejumo et al. ... based MCA which controls the sample holder and.

  4. Ogunyemi et al (17)

    African Journals Online (AJOL)

    DELL

    The results of physicochemical analysis revealed that the concentrations of ... scientific basis for regulating the discharge of potentially ... method for genotocity evaluation using Allium cepaand it ..... al., 2013). National agency for food and drug.

  5. Omotayo et al (4)

    African Journals Online (AJOL)

    DELL

    using biochemical technique and API 20E identification system. The isolates were .... sulphate, phosphate, ammonia and appearance. Heavy metals ... technique as described by Collee et al. (1989) was ..... enzymatic methods. Water Res. 36,.

  6. David et al (12)

    African Journals Online (AJOL)

    DELL

    larger mesophyll cells, xylem tissues, vascular bundles and bundle sheaths than other cultivars. Thus, larger ... mechanism to cope with drought stress. There was an ... where solar radiation is intense (Løe et al., 2007). Most ecological studies ...

  7. Cartas al editor

    Directory of Open Access Journals (Sweden)

    Facultad de Medicina Revista

    1995-10-01

    Full Text Available Con respecto al ensayo "Evaluación del aprendizaje en la educación superior" de la Dra. Análida Pinilla / Ciencia y conciencia en la medicina colombiana / Farmacovigilancia: Una necesidad urgente

  8. Kulturmorphologie als Zivilisationskritik

    DEFF Research Database (Denmark)

    Peters, Rikke Alberg

    2010-01-01

    Der Untergang des Abendlandes wird oft als dasjenige Werk betrachtet, das am tiefsten die national gefärbte Gegenüberstellung von Kultur und Zivilisation in der Zwischenkriegszeit geprägt und propagiert hat. Wie auch bei anderen Autoren der Konservativen Revolution, vor allem bei Thomas Mann und...... Arthur Moeller van den Bruck, tritt der Begriff ‚Kultur’ bei Spengler als normativer Wertbegriff auf, der im Kontrast zu einer degenerierten und seelenlosen Zivilisation steht....

  9. Microstructure of two phases alloy Al3Ti/Al3Ti0.75Fe0.25

    International Nuclear Information System (INIS)

    Angeles, C.; Rosas, G.; Perez, R.

    1998-01-01

    The titanium-aluminium system presents three intermetallic compounds from those Al 3 Ti is what less attention has received. The objective of this work is to generate and characterize the microstructure of multiphase alloys nearby to Al 3 Ti compound through Fe addition as alloying. This is because it has been seen that little precipitates of Al 2 Ti phase over Al 3 Ti intermetallic compound increases its ductility. (Author)

  10. Mineral dielectric constants and the oxide additivity rule

    International Nuclear Information System (INIS)

    Shannon, R.D.; Subramanian, M.A.; Mariano, A.N.; Rossman, G.R.

    1989-01-01

    The 1 MHz dielectric constants of a variety of synthetic aluminate garnets: Y 3 Al 5 O 12 , Ho 3 Al 5 O 12 , Y 2.93 Nd .07 Sc 2 Al 3 O 12 and Gd 2.95 Nd .05 Sc 1.98 Cr .02 Al 3 O 12 and several silicates: CaB 2 Si 2 O 8 (danburite), Ca 3 Al 2 Si 3 O 12 (grossular) and Mg 2 Al 4 Si 5 O 18 (cordierite) were determined using the two-terminal method with edge corrections. These data and polarizabilities derived from the published single crystal dielectric constants of simple oxides were used to compare compound polarizabilities obtained from the Clausius-Mosotti equation and the oxide additivity rule

  11. Coupled growth of Al-Al2Cu eutectics in Al-Cu-Ag alloys

    International Nuclear Information System (INIS)

    Hecht, U; Witusiewicz, V; Drevermann, A

    2012-01-01

    Coupled eutectic growth of Al and Al 2 Cu was investigated in univariant Al-Cu-Ag alloys during solidification with planar and cellular morphology. Experiments reveal the dynamic selection of small spacings, below the minimum undercooling spacing and show that distinct morphological features pertain to nearly isotropic or anisotropic Al-Al 2 Cu interfaces.

  12. Information of “Nukhbat al-dahr fi ‘aja’ib al-barr wa-al-bahr” by ad-Dimashqi about the Turkic Tribes of Dasht-i Kipchak »

    Directory of Open Access Journals (Sweden)

    Z.S. Ilyasova

    2016-12-01

    Full Text Available This article introduced into academic circulation information of such a historical source as “Nukhbat al-dahr fi ‘aja’ib al-barr wa-al-bahr” (Excerpts of Time on the Marvels of the Land and Sea on Kipchak clans and Turkic tribes of Dasht-i Kipchak. The material of the study is drawn from this source. Main scientific result of this work was the source’s translation into Russian accompanied by scientific comments. Sheikh Shams al-Din Abu Abdallah Muhammad Abu Talib al-Ansari al-Sufi al-Dimashqi was the author of this work. Some scholars have mistakenly confuse him with another chronicler named Shihab al-Din Ahmad ibn Yahya Ibn Fadlallah al-Omari al-Dimashqi. There is a widespread misconception that while writing on Kipchak clans and Turkic tribes al-Dimashqi used the data of such an author as Muhammad ibn Ibrahim ibn Yahya al-Ansari al-Qutub al-Warraq al-Vatvat, also known as Ahmad al-Tini. After had studying the manuscripts of al-Tini and al-Dimashqi, we did not notice the connection between these two authors regarding their information about Kipchak clans and Turkic tribes of Dasht-i Kipchak. After had studying the information about Kipchak clans and Turkic tribes of Dasht-i Kipchak, we put forward the theory that 16 ethnonyms previously identified as Kipchak clans, are actually the etnonyms of eight Kipchak clans and eight Turkic tribes. The article also contains the extraction from “Nukhbat al-dahr fi ‘aja’ib al-barr wa-al-bahr” regarding the geography of Dasht-i Kipchak and the countries inhabited by the Turks. The following data are unique in this source: 1. The text describes such rivers as Ceyhun (Amu Darya, Seyhun (Syr Darya, Itil (Volga, as well as Khorezm and Khazar Seas (Aral and Caspian Seas. 2. Additionally, this text lists the following Turkic peoples: al-Kharlukhiya (Karluks, al-Khirgaziya (Kyrgyz, al-Kaymakiya (Kimaks, al-Guzziya (Oguz, al-Bazhanakiya (Pechenegs, al-Tuguzguziya (Uighurs, al-Khulkhiya (?, al

  13. Pornographie als Metapher

    Directory of Open Access Journals (Sweden)

    Caroline Schubarth

    2010-03-01

    Full Text Available In diesem Artikel werden unterschiedliche metaphorische Verwendungen des Pornografiebegriffs und deren Implikationen untersucht. Während die Existenz von Pornografie der feministischen Anti-Porno-Bewegung als Erklärung für die anhaltende Diskriminierung von Frauen in westlichen Gesellschaften dient, nutzen rechtskonservative Kräfte den Pornografievorwurf als Rechtfertigung für die Zensur von als deviant empfundenen Identitäten und sexuellen Praktiken.This article examines different metaphorical uses of the term pornography and the resulting implications. While the existence of pornography for the feminist anti-porno movement serves as factor in the continuing discrimination of women in western societies, conservative powers on the right use the allegation of pornography as a justification for censorship of those identities and sexual practices deemed deviant.

  14. In situ synthesis of Ti{sub 2}AlC–Al{sub 2}O{sub 3}/TiAl composite by vacuum sintering mechanically alloyed TiAl powder coated with CNTs

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jian [Department of Materials Science and Engineering of Tianjin University, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Zhao, Naiqin, E-mail: nqzhao@tju.edu.cn [State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin (China); Department of Materials Science and Engineering of Tianjin University, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Nash, Philip [Thermal Processing Technology Center, Illinois Institute of Technology, IL (United States); Liu, Enzuo; He, Chunnian; Shi, Chunsheng; Li, Jiajun [Department of Materials Science and Engineering of Tianjin University, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China)

    2013-11-25

    Highlights: •Using zwitterionic surfactant to enhance the dispersion of the CNTs on the powder surface. •CNTs as carbon source decreased the formation temperature of Ti{sub 2}AlC. •Al{sub 2}O{sub 3} was generated in situ from the oxygen atoms introduced in the drying procedure. •Nanosized Ti{sub 3}Al was precipitated at 1250 °C and distribute in the TiAl matrix homogeneously. •Ti{sub 2}AlC–Al{sub 2}O{sub 3}/TiAl composite was synthesized in situ by sintering pre-alloy Ti–Al coated with CNTs. -- Abstract: Bulk Ti{sub 2}AlC–Al{sub 2}O{sub 3}/TiAl composites were in situ synthesized by vacuum sintering mechanically alloyed Ti–50 at.% Al powders coated with carbon nanotubes (CNTs). The pre-alloyed Ti–50 at.% Al powder was obtained by ball milling Ti and Al powders. The multi-walled carbon nanotubes as the carbon resource were covered on the surface of the pre-alloyed powders by immersing them into a water solution containing the CNTs. A zwitterionic surfactant was used to enhance the dispersion of the CNTs on the powder surface. The samples were cold pressed and sintered in vacuum at temperatures from 950 to 1250 °C, respectively. The results show that the reaction of forming Ti{sub 2}AlC can be achieved below 950 °C, which is 150 °C lower than in the Ti–Al–TiC system and 250 °C lower than for the Ti–Al–C system due to the addition of CNTs. Additionally, the reinforcement of Al{sub 2}O{sub 3} particles was introduced in situ in Ti{sub 2}AlC/TiAl by the drying process and subsequent sintering of the composite powders. Dense Ti{sub 2}AlC–Al{sub 2}O{sub 3}/TiAl composites were obtained by sintering at 1250 °C and exhibited a homogeneous distribution of Ti{sub 2}AlC, Al{sub 2}O{sub 3} and precipitated Ti{sub 3}Al particles and a resulting high hardness.

  15. Rupture of Al matrix in U-Mo/Al dispersion fuel by fission induced creep

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Gwan Yoon; Sohn, Dong Seong [UNIST, Daejeon (Korea, Republic of); Kim, Yeon Soo [Argonne National Laboratory, Argonnge (United States); Lee, Kyu Hong [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    This phenomenon was found specifically in the dispersion fuel plate with Si addition in the Al matrix to suppress interaction layer (IL) formation between UMo and Al. It is known that the stresses induced by fission induced swelling in U-Mo fuel particles are relieved by creep deformation of the IL, surrounding the fuel particles, that has a much higher creep rate than the Al matrix. Thus, when IL growth is suppressed, the stress is instead exerted on the Al matrix. The observed rupture in the Al matrix is believed to be caused when the stress exceeded the rupture strength of the Al matrix. In this study, the possibility of creep rupture of the Al matrix between the neighboring U-Mo fuel particles was examined using the ABAQUS finite element analysis (FEA) tool. The predicted rupture time for a plate was much shorter than its irradiation life indicating a rupture during the irradiation. The higher stress leads Al matrix to early creep rupture in this plate for which the Al matrix with lower creep strain rate does not effectively relieve the stress caused by the swelling of the U-Mo fuel particles. For the other plate, no rupture was predicted for the given irradiation condition. The effect of creeping of the continuous phase on the state of stress is significant.

  16. 12th Annual ALS Users' Association Meeting

    International Nuclear Information System (INIS)

    Robinson, Arthur L.

    1999-01-01

    Science took the front seat as 219 Advanced Light Source (ALS) users and staff gathered on Monday and Tuesday, October 18 and 19 for the twelfth annual users' meeting. The bulk of the meeting was dedicated to reports on science at the ALS. Packed into two busy days were 31 invited oral presentations and 80 submitted poster presentations, as well as time to visit 24 vendor booths. The oral sessions were dedicated to environmental science, chemical dynamics, biosciences, magnetic materials, and atomic and molecular science. In addition, there was an ALS highlights session that emphasized new results and a session comprising highlights from the young scientists who will carry the ALS into the future

  17. Separation of Mn(II) in presence of Al(III) in acid drainage from an Uranium mine with the use of chelating resins

    International Nuclear Information System (INIS)

    Soares, Eliane Pavesi B.; Gomes, Viviane T.; Vaitsman, Delmo S.

    2011-01-01

    The acid drainage of Osamu Utsumi mine is the main environmental impact from mining activities in Pocos de Caldas - MG - Brazil. The water produced in this process is characterized by high acidity and heavy metal concentration. To minimize this environmental impact, new technologies directed towards treatment of acid drainage of mine (ADM) have been studied. However, due to the presence of Al 3+ (which has a high charge) in the ADM, these resins get quickly saturated, preventing stripping of divalent cations like Mn 2+ . This study proposes the synthesis of chelating resins that provide preferential retention of Mn 2+ instead of Al 3+ . It was synthesized resins functionalized with amidoxime and dithiocarbamate. The capacity of retention of Mn 2+ e Al 3+ ions at different pH values was assessed for each resin. The stripping of Mn 2+ at 2, 3 and 4 (pH ADM range) by studied resins was not preferential for Mn 2+ in relation to Al 3+ , probably due to the strong electrostatic interaction between this last type of high charge density and the active sites from extractor agents and resins. However at pH 6 (stated by environmental norms for liquid effluents discharge) the synthesized resins had a good retention capacity for Mn 2+ . So it is proposed that the extraction technique using chelating resins could be employed to strip Mn 2+ from ADM at pH 6,0, since at this condition , Al 3+ is precipitated as Al(OH) 3 . (author)

  18. BERKELEY: ALS ring

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1993-06-15

    Everybody at Lawrence Berkeley Laboratory's Center for Beam Physics is pleased with the rapid progress in commissioning LBL's Advanced Light Source (ALS) electron storage ring, the foundation for this third-generation synchrotron radiation facility. Designed for a maximum current of 400 mA, the ALS storage ring reached 407 mA just 24 days after storing the first beam on 16 March. ALS construction as a US Department of Energy (DOE) national user facility to provide high-brightness vacuum ultra-violet and soft x-ray radiation began in October 1987. One technical requirement marking project completion was to accumulate a 50-mA current in the storage ring. The ALS passed this milestone on 24 March, a week ahead of the official deadline. Once injected, the electron beam decays quasi-exponentially primarily because of interactions with residual gas molecules in the storage-ring vacuum chamber. Eventually, when the pressure in the vacuum chamber with beam decreases toward the expected operating level of 1 nano Torr, it will only be necessary to refill the storage ring at intervals of four to eight hours. At present the vacuum is improving rapidly as surfaces are irradiated (scrubbed) by the synchrotron radiation itself. At 100 mA, beam lifetime was about one hour (9 April)

  19. Alimba et al (5)

    African Journals Online (AJOL)

    USER

    There was significant (p<0.05) increase in erythrocytes, haemoglobin ... for its anti-hemorrhoid and anti-inflammatory properties (Afolabi et al., 2008), ... genome instability which may lead to genetic related diseases ... membrane, behavioral pattern, morbidity and mortality. ..... extracts of Phyllanthus amarus in mice and rats.

  20. Taiwo et al (8)

    African Journals Online (AJOL)

    DELL

    Ife Journal of Science. (2016) vol. 18, no. 4. SPATIAL ... Ogun State. On the contrary, published work in some parts of Nigeria had ..... Prevalence among. Age Group (%). Cause of Infection. (%). Adeoye et al.,. 2007. Lagos. Kato-Katz. A. lumbricoides =29.7. Hookworm = 0.7. T. Trichiura = 18.4. S. stercoralis =0.3. Total =49.1.