WorldWideScience

Sample records for aluminium-uranium alloys estudo

  1. Alloy

    Science.gov (United States)

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

    2014-07-01

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

  2. Study of the oxidation of Fe-Cr alloys at high temperatures; Estudo da oxidacao de ligas Fe-Cr a altas temperaturas

    Energy Technology Data Exchange (ETDEWEB)

    Carneiro, J.F.; Sabioni, A.C.S. [Universidade Federal de Ouro Preto (LDM/DF/UFOP), MG (Brazil). Dept. de Fisica. Lab. de Difusao em Materiais; Trindade, V.B. [Universidade Federal de Ouro Preto (DEMM/UFOP), MG (Brazil). Dept. de Engenharia Metalurgica e de Materiais; Ji, V. [Laboratoire d' Etude des Materiaux Hors-Equilibre (LEMHE), Orsay (France)

    2010-07-01

    The high temperature oxidation behavior of Fe-1.5%Cr, Fe-5.0%Cr, Fe-10%Cr and Fe- 15%Cr model alloys were investigated from 700 to 850 deg C, in air atmosphere. The oxidation treatments were performed in a thermobalance with a sensitivity of 1{mu}g. The oxide films grown by oxidation of the alloys were characterized by scanning electronic microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). The oxide films are Fe-Cr spinels with variable composition depending on the alloy composition. For all conditions studied, the oxidation kinetics of these alloys follow a parabolic law. The comparison of the oxidation rates of the four alloys, at 700 deg C, shows that the parabolic oxidation constants decrease from 1.96x10{sup -9}g{sup 2}.cm{sup -4}.s{sup -1}, for the alloy Fe-1.5% Cr, to 1.18 x 10-14g{sup 2}.cm{sup -4}.s{sup -1} for the alloy Fe-15% Cr. Comparative analysis of the oxidation behavior of the Fe-10%Cr and Fe-15%Cr alloys, between 700 and 850 deg C, shows that the oxidation rates of these alloys are comparable to 800 deg C, above this temperature the Fe-10%Cr alloy shows lower resistance to oxidation. (author)

  3. Study of the mechanisms involved in the laser superficial hardening process of metallic alloys; Estudo dos mecanismos envolvidos no processo de endurecimento superficial a laser de ligas metalicas

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Edmara Marques Rodrigues da

    2001-07-01

    The laser superficial hardening process of a ferrous alloy (gray cast iron) and of an aluminum-silicon alloy was investigated in this work. These metallic alloys are used in the automobile industry for manufacturing cylinders and pistons, respectively. By application of individual pulses and single tracks, the involved mechanisms during the processing were studied. Variables such as energy density, power density, temporal width, beam diameter on the sample surface, atmosphere of the processing region, overlapping and scanning velocity. The hardened surface was characterized by optical and scanning electronic microscopy, dispersive energy microanalysis, X-ray mapping, X-ray diffraction, and measurements of roughness and Vickers microhardness. Depending on the processing parameters, it is possible to obtain different microstructures. The affected area of gray cast iron, can be hardened by remelting or transformation hardening (total or partial) if the reached temperature is higher or not that of melting temperature. Laser treatment originated new structures such as retained austenite, martensite and, occasionally, eutectic of cellular dendritic structure. Aluminum-silicon alloy does not have phase transformation in solid state, it can be hardened only by remelting. The increase of hardness is a function of the precipitation hardening process, which makes the silicon particles smaller and more disperse in the matrix. Maximal values of microhardness (700-1000 HV) were reached with the laser treatment in gray cast iron samples. The initial microhardness is of 242 HV. For aluminum-silicon alloy, the laser remelting increases the initial microhardness of 128 HV to the range of 160-320 HV. The found results give a new perspective for using the CLA/IPEN's laser in the heat treatment area. Besides providing a higher absorptivity to the materials, compared with the CO{sub 2} laser, and optical fiber access, the superficial hardening with Nd:YAG laser, depending on the

  4. Studies of the mechanisms involved in the laser surface hardening process of aluminum base alloys; Estudos dos mecanismos envolvidos em processos de endurecimento superficial a laser de ligas a base de aluminio

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Luciana Ventavele da

    2011-07-01

    The Al-Si alloys are widely used in industry to replace the steel and gray cast iron in high-tech sectors. The commercial importance of these alloys is mainly due to its low weight, excellent wear (abrasion) and corrosion resistance, high resistance at elevated temperatures, low coefficient of thermal expansion and lesser fuel consumption that provide considerable reduction of emission of pollutants. In this work, Al-Si alloy used in the automotive industry to manufacture pistons of internal combustion engines, was undergone to surface treatments using LASER remelting (Nd:YAG, {lambda} = 1.06 {mu}m, pulsed mode). The LASER enables various energy concentrations with accurate transfer to the material without physical contact. The intense energy transfer causes the occurrence of structural changes in the superficial layer of the material. Experiments with single pulses and trails were conducted under various conditions of LASER processing in order to analyze microstructural changes resulting from treatments and their effects on the hardness. For the characterization of hardened layer was utilized the following techniques: optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), x-ray mapping, Vickers microhardness and maximum roughness tests. The high cooling rate caused a change in the alloy structure due to the refinement of the primary eutectic silicon particles, resulting in increase of the mechanical properties (hardness) of the Al-Si alloy. (author)

  5. Estudo do efeito do tratamento superficial por moagem sobre as propriedades das partículas de uma liga de hidreto metálico Effect of a milling surface treatment on the properties of metal hydride alloy particles

    Directory of Open Access Journals (Sweden)

    Elki Cristina Souza

    2006-04-01

    Full Text Available This work reports results of studies on the electrochemical and structural properties of a Ti/Zr-based metal hydride alloy covered by Ni and LaNi4,7Sn0,3 powder additives by ball milling. The effect of this treatment is investigated for the activation time, hydrogen storage capacity and equilibrium pressure, cycling stability and the hydration/dehydration kinetics. Charge and discharge cycles show a significant decrease of the activation time due to an increase of the active area caused by the milling treatment, independent of the additive. However, other results have evidenced little effect of the milling surface treatment on the charge storage capacity, hydrogen equilibrium pressure, and hydration/dehydration kinetics, for both the Ni and LaNi4,7Sn0,3 covered materials.

  6. Dry sliding wear of Al-Fe-Cr-Mn quasicrystalline phase former alloy obtained by spray forming; Estudo do comportamento ao desgaste de liga Al-Fe-Cr-Mn obtida por conformacao por spray

    Energy Technology Data Exchange (ETDEWEB)

    Yamasaki, S.M.T.; Rios, C.T.; Botta Filho, W.J.; Bolfarini, C.; Kiminami, C.S. [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais; Gargarella, P.; Mendes, M.A.B., E-mail: marcio.andreato@gmail.co [Universidade Federal de Sao Carlos (PPG-CEMUFSCar), SP (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais

    2010-07-01

    Samples from different regions of a spray formed billet of Al{sub 92}Fe{sub 3}Cr{sub 2}Mn{sub 3} quasicrystalline phase former alloy were analyzed and their wear behavior has been studied. The microstructures observed depend on the cooling rate imposed to the material. The border of the billet exhibits a very fine structure with presence of quasicrystalline phase and the base showed a fine structure but without presence of quasicrystalline phase. Dry sliding wear tests were made using three loads and samples of these two different regions. The wear surfaces were analyzed by scanning electron microscopy and X-ray diffraction. Similar wear behavior was observed in the border and the base samples at the same load. The wear mechanism verified is the adhesive and the applied load increases the formation of Al{sub 2}O{sub 3}. These particles can take off the surface and act as abrasive, which can explain the large increase in the wear rate for the samples loaded at 30N.(author)

  7. Estudo da liga alumínio-zinco como filtração alternativa em aparelhos de raios X odontológicos Study of the aluminum-zinc alloy as an alternative means of filtration in dental X-ray devices

    Directory of Open Access Journals (Sweden)

    Claudia Fátima Silva HAITER

    2002-03-01

    Full Text Available O objetivo neste trabalho foi avaliar os efeitos da filtração alternativa da liga alumínio-zinco em aparelhos de raios X odontológicos, em relação ao espectro de energia dos feixes de raios X, a taxa de kerma no ar, o índice de contraste nas radiografias obtidas e a qualidade das imagens radiográficas. Este estudo foi realizado comparando-se o filtro convencional de alumínio com várias espessuras do filtro de liga alumínio-zinco, em diferentes porcentagens do elemento zinco na liga (2%, 3%, 4% e 5%. Foi utilizado um aparelho de raios X odontológico convencional, operando com 60 kVp e 70 kVp, e filmes radiográficos dos grupos D e E de sensibilidade. Foram realizadas radiografias de um "phantom" e de uma escala de densidade de alumínio. Os resultados mostraram que o uso dos filtros de liga Al-Zn resultou em um não-endurecimento dos feixes. A taxa de kerma no ar diminuiu em até 18,53%, sem alteração no contraste das radiografias e a qualidade das imagens teve uma boa aceitação pelos examinadores. A análise dos resultados nos levou a concluir que o filtro de liga Al-Zn 2%, com 1,99 mm de espessura, tensão de 60 kVp, quando usado com filme D, foi o que obteve melhor desempenho, reduzindo a taxa de kerma no ar sem variar o índice de contraste das radiografias, mantendo a qualidade da imagem aceitável para diagnóstico, sem contudo aumentar o tempo de exposição.The aim of this study was to evaluate the effects of alternative filtration with the aluminum-zinc alloy in dental X-ray devices, regarding the energy spectrum, dose, contrast and image quality. This study was carried out comparing the conventional aluminum filter with aluminum-zinc alloy filters of various thicknesses and with different percentages of zinc in the alloy (2, 3, 4 and 5%. A conventional X-ray device operating with 60 and 70 kVp as well as D- and E-speed films were utilized in order to obtain images of a phantom and an aluminum step wedge. The utilization

  8. um estudo de caso

    OpenAIRE

    Costa, Cátia Filipa Pereira da

    2011-01-01

    Dissertação apresentada à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Psicologia Jurídica As situações de abuso sexual de crianças nas quais o perpetrador pertence ao sexo feminino obtiveram ao longo dos últimos anos um acrescido reconhecimento por parte da comunidade científica, evidenciado pelo significativo incremento das investigações no âmbito desta temática consistindo na sua maioria estudos de caso. Um conjunto de particularidades encont...

  9. Aluminum alloy

    Science.gov (United States)

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

    1989-01-01

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

  10. Electrical Resistance Alloys and Low-Expansion Alloys

    DEFF Research Database (Denmark)

    Kjer, Torben

    1996-01-01

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

  11. A study of the process of Nd{sub 15} Fe{sub 77} B{sub 8} magnetic alloy preparation by calciothermic reduction diffusion (R/D); Estudo do processo de obtencao da liga magnetica Nd{sub 15} Fe{sub 77} B{sub 8} por reducao-difusao (R/D) calciotermica

    Energy Technology Data Exchange (ETDEWEB)

    Graca Guilherme, Eneida da; Paschoal, Jose O.A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    1992-12-31

    In this work the manufacturing of Nd{sub 15}, Fe{sub 77}, B{sub 8} alloy powder for high-performance permanent magnets by reduction-diffusion process was investigated. The effect of variables such as the excess amount of neodymium oxide, the removal of calcium oxide by selective leaching and milling of alloy was examined. (author). 8 refs., 8 figs., 5 tab.s.

  12. Study of a Ti Ni-based shape memory alloy aiming applications in pipeline connections of the oil and gas industry; Estudo de uma liga base Ti-Ni com memoria de forma visando aplicacoes em conexoes de tubulacoes na industria do petroleo e gas

    Energy Technology Data Exchange (ETDEWEB)

    Silva, M.M. da; Silva, N.J. da; Gomes, A.A.C.; Reis, R.P.B.; Araujo, C.J. de; Santos, M.A. dos [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Lab. Multidisciplinar de Materiais e Estruturas Ativas (LaMMEA)], e-mail: carlos@dem.ufcg.edu.br

    2006-07-01

    The objective of this paper is to study the technical feasibility of a TiNi-based Shape Memory Alloy (SMA) with potential application in connections of the oil and gas Sector. The employment of this alloy would increase the reliability of these unions. Thus, a 45,0 Ti-55,0 Ni (% wt) SMA has been manufactured through the plasma skull melting and with subsequent conformation by the Push-Pull method. Samples of this SMA were heat treated at 1173 K during 900s, followed by water quenching. These samples were characterized by optic microscopy, microhardness, differential scanning calorimetry (DSC), and force generation tests. The obtained TiNi SMA has presented an important wide temperature hysteresis. The generated forces substantiate the potential application of these alloys in connection systems of the oil and gas Sector. (author)

  13. Estudo multicasos sobre atividades inovativas

    Directory of Open Access Journals (Sweden)

    Sonia Regina Hierro Parolin

    2013-09-01

    Full Text Available Em estudos sobre competitividade argumenta-se que as empresas necessitam de estratégias baseadas em inovações e de capacidades internas em constantes e intensas transformações, não somente nos padrões tecnológicos, mas também no encadeamento do processo de gestão das atividades inovativas, como processos dinâmicos, não lineares e diversificados, em função de múltiplos fatores dos ambientes interno e externo. Para contribuir com essas discussões, neste artigo apresenta-se um estudo multicasos em quatro indústrias de médio e grande portes, de segmentos, densidades tecnológicas e históricos com inovações diferentes entre si. Como principais resultados, salientam-se o encadeamento das atividades inovativas como parte de uma estratégia organizacional para obter resultados com inovação e a afluência de todas as pessoas, e não somente as alocadas em pesquisa e desenvolvimento, para o cumprimento dessa estratégia.

  14. Survey of the chemical diffusion at infinite dilution in the nickel-plutonium and aluminium-uranium systems; Contribution a l'etude de l'heterodiffusion a dilution infinie systemes nickel-plutonium et aluminium-uranium

    Energy Technology Data Exchange (ETDEWEB)

    Blechet, J.J. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1968-09-01

    Solubility S{sub 0} and chemical diffusion coefficients D{sub PuNi} at infinite dilution of plutonium in nickel have been determined by autoradiography {alpha} in poly-phased system by the welded couples method: S{sub 0} varies from 40 to 80.10{sup -6} (atomic concentration) and D{sub PuNi} follows an Arrhenius law D = D{sub 0} exp (-Q/RT) with 0.03 cm{sup 2}/s < D{sub 0} < 1.6 cm{sup 2}/s and 46000 cal/mole < Q < 56000 cal/mole. Diffusion of uranium in aluminium have been carried out by fissiography using the thin layer method. Frequency factor lies between 0.01 and 3.1 cm{sup 2}/s and the activation energy lies between 24000 and 34000 cal/mole. (author) [French] La solubilite S{sub 0} et les coefficients de diffusion chimique D{sub PuNi}, a dilution infinie, du plutonium dans le nickel ont ete determines par autoradiographie {alpha} sur des couples soudes en systeme polyphase. Entre 1000 et 1125 deg. C. S{sub 0} varie de 40 a 80.10{sup -6} et D obeit a une loi d'ARRHENIUS (concentration atomique) D = D{sub 0} exp (-Q/RT) avec 0.03 cm{sup 2}s{sup -1} < D{sub 0} < 1.60 cm{sup 2}s{sup -1} 46000 calories par mole < Q < 56000 calories par mole. La diffusion de l'uranium dans l'aluminium a ete etudiee par fissiographie en utilisant la technique du depot mince. Le facteur de frequence est situe entre 0.01 et 3.1 cm{sup 2}s{sup -1} et l'energie d'activation entre 24000 et 34000 calories par mole. (auteur)

  15. Study of the microstructural and mechanical properties of titanium-niobium-zirconium based alloys processed with hydrogen and powder metallurgy for use in dental implants; Estudo das propriedades mecanicas e microestruturais de ligas a base de titanio-niobiozirconio processados com hidrogenio e metalurgia do po para utilizacao em implantes dentarios

    Energy Technology Data Exchange (ETDEWEB)

    Duvaizem, Jose Helio

    2009-07-01

    Hydrogen has been used as pulverization agent in alloys based on rare earth and transition metals due to its extremely high diffusion rate even on low temperatures. Such materials are used on hydrogen storage dispositives, generation of electricity or magnetic fields, and are produced by a process which the first step is the transformation of the alloy in fine powder by miling. Besides those, hydrogenium is also being used to obtain alloys based on titanium - niobium - zirconium in the pulverization. Powder metallurgy is utilized on the production of these alloys, making it possible to obtain structures with porous surface as result, requirement for its application as biomaterials. Other advantages of powder metallurgy usage include better surface finish and better microstructural homogeneity. In this work samples were prepared in the Ti-13Nb-13Zr composition. The hydrogenation was performed at 700 degree C, 600 degree C, and 500 degree C for titanium, niobium and zirconium respectively. After hydrogenation, the milling stage was carried out on high energy planetary ball milling with 200rpm during 90 minutes, and also in conventional ball milling for 30 hours. Samples were pressed in uniaxial press, followed by isostatic cold press, and then sintered at 1150 degree C for 7-13 hours. Microstructural properties of the samples were characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and x-ray diffraction. Mechanical and structural properties determined were density, microhardness and moduli of elasticity. The sample sintered at 1150 degree C for 7h, hydrogenated using 10.000 mbar and produced by milling on high energy planetary ball milling presented the best mechanical properties and microstructural homogeneity. (author)

  16. Study of the effect of heat treatments and the addition of oxygen on the microstructure and mechanical properties of Ti-15Mo alloy used as biomaterials; Estudo do efeito de tratamentos termicos e da adicao de oxigenio na microestrutura e propriedades mecanicas da liga Ti-15Mo utilizada como biomaterial

    Energy Technology Data Exchange (ETDEWEB)

    Martins Junior, J.R.S.; Araujo, R.O.; Nogueira, R.A.; Grandini, C.R., E-mail: jrsmjr@fc.unesp.b [Universidade Estadual Paulista (UNESP), Bauru, SP (Brazil). Lab. de Anelasticidade e Biomateriais; Claro, A.P.R.A. [Universidade Estadual Paulista (FEG/UNESP), Guaratingueta, SP (Brazil). Fac. de Engenharia

    2010-07-01

    The Ti-15Mo alloy has its mechanical properties strongly modified by heat treatments and the addition of interstitial elements such as oxygen, for example. In this sense, the objective of this paper is to evaluate the effect of heat treatment and the introduction of oxygen on the microstructure and mechanical properties of Ti-15% pMo alloy. The samples used in this work consist of Ti containing 15% in weight of molybdenum, which were characterized by density measurements, X-ray diffraction, optical and scanning electron microscopy, microhardness and mechanical spectroscopy. The diffraction patterns were analyzed by Rietveld method, where it was possible to obtain the lattice parameters and the amount (in %) of each phase present in the microstructure. The results of optical and scanning electron microscopy are consistent with the X-ray diffraction, showing a predominance of structures of the beta type. The elasticity modulus obtained was about 90 GPa, indicating that this is a promising alloy for use in dental implants. (author)

  17. Studies of the development and characterization of the Cu-Ni-Pt and Cu-Ni-Sn alloys for electro-electronic uses; Estudos do desenvolvimento e caracterizacao das ligas Cu-Ni-Pt e Cu-Ni-Sn para fins eletro-eletronicos

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Luis Carlos Elias da

    2006-07-01

    The Cu and its alloys have different applications in the owed modern society the excellent electric properties, thermal conductivity, resistance to the corrosion and other properties. These applications can be in valves, pipes, pots for absorption of solar energy, radiators for automobiles, current driver, electronic driver, thermostats elements and structural parts of nuclear reactors, as, for example, reels for field toroidal for a reactor of nuclear coalition. The alloys used in nuclear reactors, we can highlight Cu-Be, Cu-Sn and Cu-Pt. Ni and Co frequently are added to the Cu alloys so that the solubility is moved for temperatures more elevated with relationship to the binary systems of Cu-Sn and Cu-Pt. The addition of Ni-Pt or Ni-Sn to the Cu in the same or inferior percentages to 1,5% plus thermomechanical treatments changes the properties of the copper. We studied the electric conductivity and hardness Vickers of the Cu-Ni-Pt and Cu-Ni-Sn and compared with the electrolytic Cu. In the proposed flowcharts, breaking of the obtaining of the ingot, we proceeded with thermo mechanical treatments. (author)

  18. Translating VDM to Alloy

    DEFF Research Database (Denmark)

    Lausdahl, Kenneth

    2013-01-01

    . Traditionally, theorem provers are used to prove that specifications are correct but this process is highly dependent on expert users. Alternatively, model finding has proved to be useful for validation of specifications. The Alloy Analyzer is an automated model finder for checking and visualising Alloy...... specifications. However, to take advantage of the automated analysis of Alloy, the model-oriented VDM specifications must be translated into a constraint-based Alloy specifications. We describe how a sub- set of VDM can be translated into Alloy and how assertions can be expressed in VDM and checked by the Alloy...

  19. Alloy Fabrication Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — At NETL’s Alloy Fabrication Facility in Albany, OR, researchers conduct DOE research projects to produce new alloys suited to a variety of applications, from gas...

  20. Turbine Blade Alloy

    Science.gov (United States)

    MacKay, Rebecca

    2001-01-01

    The High Speed Research Airfoil Alloy Program developed a fourth-generation alloy with up to an +85 F increase in creep rupture capability over current production airfoil alloys. Since improved strength is typically obtained when the limits of microstructural stability are exceeded slightly, it is not surprising that this alloy has a tendency to exhibit microstructural instabilities after high temperature exposures. This presentation will discuss recent results obtained on coated fourth-generation alloys for subsonic turbine blade applications under the NASA Ultra-Efficient Engine Technology (UEET) Program. Progress made in reducing microstructural instabilities in these alloys will be presented. In addition, plans will be presented for advanced alloy development and for computational modeling, which will aid future alloy development efforts.

  1. F-Alloy: An Alloy Based Model Transformation Language

    OpenAIRE

    Gammaitoni, Loïc; Kelsen, Pierre

    2015-01-01

    Model transformations are one of the core artifacts of a model-driven engineering approach. The relational logic language Alloy has been used in the past to verify properties of model transformations. In this paper we introduce the concept of functional Alloy modules. In essence a functional Alloy module can be viewed as an Alloy module representing a model transformation. We describe a sublanguage of Alloy called F-Alloy that allows the specification of functional Alloy modules. Module...

  2. PLUTONIUM-THORIUM ALLOYS

    Science.gov (United States)

    Schonfeld, F.W.

    1959-09-15

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

  3. Disturbios da olfacao: estudo retrospectivo

    Directory of Open Access Journals (Sweden)

    Luciano Lobato Gregorio

    2014-01-01

    Full Text Available Introdução: O olfato, fenômeno subjetivo de grande importância, é pouco compreendido e estudado no ser humano. Médicos com maior conhecimento sobre os distúrbios desse sentido tendem a considerar a doença mais importante e manejar melhor o diagnóstico e o tratamento. Objetivo: Descrever a amostra dos pacientes com queixa principal de distúrbios do olfato e mostrar a experiência do serviço no manejo e tratamento. Delineamento: Estudo retrospectivo de coorte histórica com corte transversal. Materiais e métodos: Descrição da amostra e avaliação de resposta ao tratamento de pacientes com queixa principal de hiposmia ou anosmia atendidos no ambulatório de Rinologia no período de janeiro de 2005 a outubro de 2011. Resultados: Dos 38 pacientes com distúrbio da olfação, 68,4% dos pacientes apresentaram queixa de hiposmia e 31,5% de anosmia, com duração média de 30,8 meses. Os diagnósticos etiológicos principais foram idiopática (31,5%, rinopatia alérgica (28,9% e RSC com pólipos (10,5%. As respostas ao tratamento com corticosteroide tópico e ácido alfa-lipoico foram variáveis, assim como na literatura. Conclusão: Maior importância deve ser dada aos distúrbios do olfato na prática do otorrinolaringologista, uma vez que o diagnóstico diferencial é amplo e pode trazer grande morbidade ao paciente, com impacto na sua qualidade de vida.

  4. High strength alloys

    Science.gov (United States)

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

    2012-06-05

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

  5. High strength alloys

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-08-31

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

  6. Biocompatibility of dental alloys

    Energy Technology Data Exchange (ETDEWEB)

    Braemer, W. [Heraeus Kulzer GmbH and Co. KG, Hanau (Germany)

    2001-10-01

    Modern dental alloys have been used for 50 years to produce prosthetic dental restorations. Generally, the crowns and frames of a prosthesis are prepared in dental alloys, and then veneered by feldspar ceramics or composites. In use, the alloys are exposed to the corrosive influence of saliva and bacteria. Metallic dental materials can be classified as precious and non-precious alloys. Precious alloys consist of gold, platinum, and small amounts of non-precious components such as copper, tin, or zinc. The non-precious alloys are based on either nickel or cobalt, alloyed with chrome, molybdenum, manganese, etc. Titanium is used as Grade 2 quality for dental purposes. As well as the dental casting alloys, high purity electroplated gold (99.8 wt.-%) is used in dental technology. This review discusses the corrosion behavior of metallic dental materials with saliva in ''in vitro'' tests and the influence of alloy components on bacteria (Lactobacillus casei and Streptococcus mutans). The test results show that alloys with high gold content, cobalt-based alloys, titanium, and electroplated gold are suitable for use as dental materials. (orig.)

  7. Creep Resistant Zinc Alloy

    Energy Technology Data Exchange (ETDEWEB)

    Frank E. Goodwin

    2002-12-31

    This report covers the development of Hot Chamber Die Castable Zinc Alloys with High Creep Strengths. This project commenced in 2000, with the primary objective of developing a hot chamber zinc die-casting alloy, capable of satisfactory service at 140 C. The core objectives of the development program were to: (1) fill in missing alloy data areas and develop a more complete empirical model of the influence of alloy composition on creep strength and other selected properties, and (2) based on the results from this model, examine promising alloy composition areas, for further development and for meeting the property combination targets, with the view to designing an optimized alloy composition. The target properties identified by ILZRO for an improved creep resistant zinc die-casting alloy were identified as follows: (1) temperature capability of 1470 C; (2) creep stress of 31 MPa (4500 psi); (3) exposure time of 1000 hours; and (4) maximum creep elongation under these conditions of 1%. The project was broadly divided into three tasks: (1) Task 1--General and Modeling, covering Experimental design of a first batch of alloys, alloy preparation and characterization. (2) Task 2--Refinement and Optimization, covering Experimental design of a second batch of alloys. (3) Task 3--Creep Testing and Technology transfer, covering the finalization of testing and the transfer of technology to the Zinc industry should have at least one improved alloy result from this work.

  8. Creep Resistant Zinc Alloy

    Energy Technology Data Exchange (ETDEWEB)

    Frank E. Goodwin

    2002-12-31

    This report covers the development of Hot Chamber Die Castable Zinc Alloys with High Creep Strengths. This project commenced in 2000, with the primary objective of developing a hot chamber zinc die-casting alloy, capable of satisfactory service at 140 C. The core objectives of the development program were to: (1) fill in missing alloy data areas and develop a more complete empirical model of the influence of alloy composition on creep strength and other selected properties, and (2) based on the results from this model, examine promising alloy composition areas, for further development and for meeting the property combination targets, with the view to designing an optimized alloy composition. The target properties identified by ILZRO for an improved creep resistant zinc die-casting alloy were identified as follows: (1) temperature capability of 1470 C; (2) creep stress of 31 MPa (4500 psi); (3) exposure time of 1000 hours; and (4) maximum creep elongation under these conditions of 1%. The project was broadly divided into three tasks: (1) Task 1--General and Modeling, covering Experimental design of a first batch of alloys, alloy preparation and characterization. (2) Task 2--Refinement and Optimization, covering Experimental design of a second batch of alloys. (3) Task 3--Creep Testing and Technology transfer, covering the finalization of testing and the transfer of technology to the Zinc industry should have at least one improved alloy result from this work.

  9. Catalyst Alloys Processing

    Science.gov (United States)

    Tan, Xincai

    2014-10-01

    Catalysts are one of the key materials used for diamond formation at high pressures. Several such catalyst products have been developed and applied in China and around the world. The catalyst alloy most widely used in China is Ni70Mn25Co5 developed at Changsha Research Institute of Mining and Metallurgy. In this article, detailed techniques for manufacturing such a typical catalyst alloy will be reviewed. The characteristics of the alloy will be described. Detailed processing of the alloy will be presented, including remelting and casting, hot rolling, annealing, surface treatment, cold rolling, blanking, finishing, packaging, and waste treatment. An example use of the catalyst alloy will also be given. Industrial experience shows that for the catalyst alloy products, a vacuum induction remelt furnace can be used for remelting, a metal mold can be used for casting, hot and cold rolling can be used for forming, and acid pickling can be used for metal surface cleaning.

  10. PLUTONIUM-ZIRCONIUM ALLOYS

    Science.gov (United States)

    Schonfeld, F.W.; Waber, J.T.

    1960-08-30

    A series of nuclear reactor fuel alloys consisting of from about 5 to about 50 at.% zirconium (or higher zirconium alloys such as Zircaloy), balance plutonium, and having the structural composition of a plutonium are described. Zirconium is a satisfactory diluent because it alloys readily with plutonium and has desirable nuclear properties. Additional advantages are corrosion resistance, excellent fabrication propenties, an isotropie structure, and initial softness.

  11. NICKEL-BASE ALLOY

    Science.gov (United States)

    Inouye, H.; Manly, W.D.; Roche, T.K.

    1960-01-19

    A nickel-base alloy was developed which is particularly useful for the containment of molten fluoride salts in reactors. The alloy is resistant to both salt corrosion and oxidation and may be used at temperatures as high as 1800 deg F. Basically, the alloy consists of 15 to 22 wt.% molybdenum, a small amount of carbon, and 6 to 8 wt.% chromium, the balance being nickel. Up to 4 wt.% of tungsten, tantalum, vanadium, or niobium may be added to strengthen the alloy.

  12. O desamparo aprendido revisitado: estudos com animais

    Directory of Open Access Journals (Sweden)

    Maria Helena Leite Hunziker

    Full Text Available O desamparo aprendido tem sido definido como a dificuldade de aprendizagem apresentada por indivíduos que tiveram experiência prévia com estímulos aversivos incontroláveis. O objetivo deste trabalho é fazer uma revisão crítica dos estudos sobre o desamparo aprendido, com animais. Nessa análise, são considerados aspectos conceituais e metodológicos dos estudos em questão e as interpretações teóricas sobre esse efeito comportamental. Aborda-se a evolução histórica desses estudos, bem como alguns aspectos controversos das publicações que se acumularam ao longo de quatro décadas de pesquisa. A associação do desamparo aprendido com a depressão clínica é analisada criticamente, destacando-se a necessidade de maior rigor metodológico e conceitual nos estudos da área.

  13. Ductile transplutonium metal alloys

    Science.gov (United States)

    Conner, William V.

    1983-01-01

    Alloys of Ce with transplutonium metals such as Am, Cm, Bk and Cf have properties making them highly suitable as sources of the transplutonium element, e.g., for use in radiation detector technology or as radiation sources. The alloys are ductile, homogeneous, easy to prepare and have a fairly high density.

  14. Ultrahigh temperature intermetallic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Brady, M.P.; Zhu, J.H.; Liu, C.T.; Tortorelli, P.F.; Wright, J.L.; Carmichael, C.A.; Walker, L.R. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

    1997-12-01

    A new family of Cr-Cr{sub 2}X based alloys with fabricability, mechanical properties, and oxidation resistance superior to previously developed Cr-Cr{sub 2}Nb and Cr-Cr{sub 2}Zr based alloys has been identified. The new alloys can be arc-melted/cast without cracking, and exhibit excellent room temperature and high-temperature tensile strengths. Preliminary evaluation of oxidation behavior at 1100 C in air indicates that the new Cr-Cr{sub 2}X based alloys form an adherent chromia-based scale. Under similar conditions, Cr-Cr{sub 2}Nb and Cr-Cr{sub 2}Zr based alloys suffer from extensive scale spallation.

  15. Mg based alloys obtained by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez, S. [Univ. de Santiago de Chile (Chile). Fac. de Ingenieria; Garcia, G.; Serafini, D.; San Martin, A.

    1999-07-01

    In the present work, we studied the production of magnesium alloys, of stoichiometry 2Mg + Ni, by mechanical alloying (MA) and the behavior of the alloys under hydrogen in a Sievert`s type apparatus. The elemental powders were milled under argon atmosphere in a Spex 8000 high energy ball mill. The milled materials were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Only minimum amounts of the Mg{sub 2}Ni intermetallic compound was obtained after 22 h of milling time. Most of the material was sticked to the inner surface of the container as well as to the milling balls. Powders milled only for 12 hours transforms to the intermetallic at around 433 K. Effects of the MA on the hydrogen absorption kinetics were also studied. (orig.) 10 refs.

  16. SURFACE MELTING OF ALUMINIUM ALLOYS

    OpenAIRE

    Veit, S.; Albert, D; Mergen, R.

    1987-01-01

    The wear properties of aluminium base alloys are relatively poor. Laser surface melting and alloying has proved successful in many alloy systems as a means of significantly improving the surface properties. The present work describes experiments designed to establish the scope of laser treatment of aluminium alloys. Aluminium does not absorb CO2 laser light as well as other metals which necessitated first a general study of absorption caotings. Aluminium alloys offer fewer opportunities than ...

  17. Analysis of niobium alloys.

    Science.gov (United States)

    Ferraro, T A

    1968-09-01

    An ion-exchange method was applied to the analysis of synthetic mixtures representing various niobium-base alloys. The alloying elements which were separated and determined include vanadium, zirconium, hafnium, titanium, molybdenum, tungsten and tantalum. Mixtures containing zirconium or hafnium, tungsten, tantalum and niobium were separated by means of a single short column. Coupled columns were employed for the resolution of mixtures containing vanadium, zirconium or titanium, molybdenum, tungsten and niobium. The separation procedures and the methods employed for the determination of the alloying elements in their separate fractions are described.

  18. TUNGSTEN BASE ALLOYS

    Science.gov (United States)

    Schell, D.H.; Sheinberg, H.

    1959-12-15

    A high-density quaternary tungsten-base alloy having high mechanical strength and good machinability composed of about 2 wt.% Ni, 3 wt.% Cu, 5 wt.% Pb, and 90wt.% W is described. This alloy can be formed by the powder metallurgy technique of hot pressing in a graphite die without causing a reaction between charge and the die and without formation of a carbide case on the final compact, thereby enabling re-use of the graphite die. The alloy is formable at hot- pressing temperatures of from about 1200 to about 1350 deg C. In addition, there is little component shrinkage, thereby eliminating the necessity of subsequent extensive surface machining.

  19. Standard Specification for Copper-Aluminum-Silicon-Cobalt Alloy, Copper-Nickel-Silicon-Magnesium Alloy, Copper-Nickel-Silicon Alloy, Copper-Nickel-Aluminum-Magnesium Alloy, and Copper-Nickel-Tin Alloy Sheet and Strip

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2015-01-01

    Standard Specification for Copper-Aluminum-Silicon-Cobalt Alloy, Copper-Nickel-Silicon-Magnesium Alloy, Copper-Nickel-Silicon Alloy, Copper-Nickel-Aluminum-Magnesium Alloy, and Copper-Nickel-Tin Alloy Sheet and Strip

  20. Alloy Selection System

    Energy Technology Data Exchange (ETDEWEB)

    None

    2001-02-01

    Software will Predict Corrosion Rates to Improve Productivity in the Chemical Industry. Many aspects of equipment design and operation are influenced by the choice of the alloys used to fabricate process equipment.

  1. Strength of Hard Alloys,

    Science.gov (United States)

    Partial replacement of titanium carbide by tantalum carbide in three-phase WC-TiC-Co alloys tends to have a favorable effect on mechanical properties such as fatigue strength under bending and impact durability.

  2. First Everlasting Alloy

    Institute of Scientific and Technical Information of China (English)

    杨仲言

    1994-01-01

    There′s new alloy that apparently just won′t give up. When a pin was scraped along it the equivalent of one million times, the alloy-made of zirconium, palladium, and ruthenium—displayed no net loss of surface material. When astonished researchers at the National Institute of Standards and Technology(NIST) persevered with a five-million-cycle wear test, they got the same result.

  3. Machining of titanium alloys

    CERN Document Server

    2014-01-01

    This book presents a collection of examples illustrating the resent research advances in the machining of titanium alloys. These materials have excellent strength and fracture toughness as well as low density and good corrosion resistance; however, machinability is still poor due to their low thermal conductivity and high chemical reactivity with cutting tool materials. This book presents solutions to enhance machinability in titanium-based alloys and serves as a useful reference to professionals and researchers in aerospace, automotive and biomedical fields.

  4. Correlation between diffusion barriers and alloying energy in binary alloys

    DEFF Research Database (Denmark)

    Vej-Hansen, Ulrik Grønbjerg; Rossmeisl, Jan; Stephens, Ifan;

    2016-01-01

    In this paper, we explore the notion that a negative alloying energy may act as a descriptor for long term stability of Pt-alloys as cathode catalysts in low temperature fuel cells.......In this paper, we explore the notion that a negative alloying energy may act as a descriptor for long term stability of Pt-alloys as cathode catalysts in low temperature fuel cells....

  5. ESTUDO SOBRE O IMPACTO DOS PROCESSADORES HOSPEDEIROS

    Directory of Open Access Journals (Sweden)

    Alba S. B. Lopes

    2008-05-01

    Full Text Available Arquiteturas reconfiguráveis são dispositivos de hardware capazes de modificar sua estrutura de hardware de acordo com a aplicação a ser executada. Tais dispositivos surgiram como uma alternativa às soluções de hardware tradicionais na tentativa de equilibrar flexibilidade e desempenho. Uma das principais formas de utilização de arquiteturas reconfiguráveis corresponde a um bloco reconfigurável anexado a um processador hospedeiro. Esse processador é responsável por executar diversas tarefas críticas, incluindo o particionamento hardware/software e indicar o momento do bloco reconfigurável executar. Apesar de existirem diversas propostas de arquiteturas reconfiguráveis na literatura, pouco se estudou sobre o impacto do processador hospedeiro na arquitetura. Nesse contexto, esse artigo apresenta um estudo sobre o impacto do processador hospedeiro no desempenho da arquitetura reconfigurável híbrida. Como estudo de caso foi realizada uma avaliação sobre o uso dos processadores SPARC V8 da Sun Microsystems e Nios II da Altera como processadores hospedeiros da arquitetura reconfigurável híbrida RoSA. O objetivo deste estudo é realizar a comparação entre o desempenho desses processadores e identificar qual deles é o mais adequado para anexar a arquitetura em questão. Os resultados mostraram que foi possível alcançar até 47% de ganho de desempenho com o uso do processador Nios II em comparação ao SPARC V8, indicando o primeiro como mais adequado para a arquitetura RoSA. PALAVRAS-CHAVE: arquiteturas reconfiguráveis, processador hospedeiro, desempenho.

  6. Impact toughness of laser alloyed aluminium AA1200 alloys

    CSIR Research Space (South Africa)

    Mabhali, Luyolo AB

    2013-08-01

    Full Text Available Laser surface alloying of aluminium AA1200 was performed with a 4kW Nd:YAG laser and impact resistance of the alloys was investigated. The alloying powders were a mixture of Ni, Ti and SiC in different proportions. Surfaces reinforced...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-07-01

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

  8. INVESTIGATION OF MAGNESIUM ALLOYS MACHINABILITY

    Directory of Open Access Journals (Sweden)

    Berat Barıs BULDUM

    2013-01-01

    Full Text Available Magnesium is the lightest structural metal. Magnesium alloys have a hexagonal lattice structure, which affects the fundamental properties of these alloys. Plastic deformation of the hexagonal lattice is more complicated than in cubic latticed metals like aluminum, copper and steel. Magnesium alloy developments have traditionally been driven by industry requirements for lightweight materials to operate under increasingly demanding conditions. Magnesium alloys have always been attractive to designers due to their low density, only two thirds that of aluminium and its alloys [1]. The element and its alloys take a big part of modern industry needs. Especially nowadays magnesium alloys are used in automotive and mechanical (trains and wagons manufacture, because of its lightness and other features. Magnesium and magnesium alloys are the easiest of all metals to machine, allowing machining operations at extremely high speed. All standard machining operations such as turning, drilling, milling, are commonly performed on magnesium parts.

  9. Selective dissolution in binary alloys

    Science.gov (United States)

    McCall, Carol Rene

    Corrosion is an important issue in the design of engineering alloys. De-alloying is an aspect of alloy corrosion related to the selective dissolution of one or more of the components in an alloy. The work reported herein focuses on the topic of de-alloying specific to single-phase binary noble metal alloy systems. The alloy systems investigated were gold-silver and gold-copper. The onset of a bulk selective dissolution process is typically marked by a critical potential whereby the more reactive component in the alloy begins dissolving from the bulk, leading to the formation of a bi-continuous solid-void morphology. The critical potential was investigated for the entire composition range of gold-silver alloys. The results presented herein include the formulation of an expression for critical potential as a function of both alloy and electrolyte composition. Results of the first investigation of underpotential deposition (UPD) on alloys are also presented herein. These results were implemented as an analytical tool to provide quantitative measurements of the surface evolution of gold during de-alloying. The region below the critical potential was investigated in terms of the compositional evolution of the alloy surface. Below the critical potential, there is a competition between the dissolution of the more reactive alloying constituent (either silver or copper) and surface diffusion of gold that serves to cover dissolution sites and prevent bulk dissolution. By holding the potential at a prescribed value below the critical potential, a time-dependent gold enrichment occurs on the alloy surface leading to passivation. A theoretical model was developed to predict the surface enrichment of gold based on the assumption of layer-by-layer dissolution of the more reactive alloy constituent. The UPD measurements were used to measure the time-dependent surface gold concentration and the results agreed with the predictions of the theoretical model.

  10. Structural thermodynamics of alloys

    CERN Document Server

    Manenc, Jack

    1973-01-01

    Technical progress has for a very long time been directly dependent on progress in metallurgy, which is itself connected with improvements in the technology of alloys. Metals are most frequently used in the form of alloys for several reasons: the quantity of pure metal in its native state in the earth's crust is very limited; pure metals must be extracted from ores which are themselves impure. Finally, the methods of treatment used lead more easily to alloys than to pure metals. The most typical case is that of iron, where a pure ore may be found, but which is the starting point for cast iron or steel, alloys of iron and carbon. In addition, the properties of alloys are in general superior to those of pure metals and modem metallurgy consists of controlling these properties so as to make them conform to the requirements of the design office. Whilst the engineer was formerly compelled to adapt his designs and constructions to the materials available, such as wood, stone, bronze, iron, cast iron and ordinary st...

  11. De-alloyed platinum nanoparticles

    Science.gov (United States)

    Strasser, Peter [Houston, TX; Koh, Shirlaine [Houston, TX; Mani, Prasanna [Houston, TX; Ratndeep, Srivastava [Houston, TX

    2011-08-09

    A method of producing de-alloyed nanoparticles. In an embodiment, the method comprises admixing metal precursors, freeze-drying, annealing, and de-alloying the nanoparticles in situ. Further, in an embodiment de-alloyed nanoparticle formed by the method, wherein the nanoparticle further comprises a core-shell arrangement. The nanoparticle is suitable for electrocatalytic processes and devices.

  12. Shape Memory Alloys

    Directory of Open Access Journals (Sweden)

    Deexith Reddy

    2016-07-01

    Full Text Available Shape memory alloys (SMAs are metals that "remember" their original shapes. SMAs are useful for such things as actuators which are materials that "change shape, stiffness, position, natural frequency, and other mechanical characteristics in response to temperature or electromagnetic fields" The potential uses for SMAs especially as actuators have broadened the spectrum of many scientific fields. The study of the history and development of SMAs can provide an insight into a material involved in cutting-edge technology. The diverse applications for these metals have made them increasingly important and visible to the world. This paper presents the working of shape memory alloys , the phenomenon of super-elasticity and applications of these alloys.

  13. Neutron absorbing alloy

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Masayuki

    1998-12-04

    The neutron absorbing alloy of the present invention comprises Ti or an alloy thereof as a mother material, to which from 2 to 40% by weight of Hf and Gd within a range of from 4 to 50% by weight in total are added respectively. Ti is excellent in specific strength, corrosion resistance and workability, and produces no noxious intermetallic compound with Hf and Gd. In addition, since the alloy can incorporate a great quantity of Hf and Gd, a neutron absorbing material having excellent neutron absorbing performance than usual and excellent in specific strength, corrosion resistance and workability can be manufactured conveniently and economically not by a special manufacturing method. (T.M.)

  14. Double Glow Plasma Surface Alloyed Burn-resistant Titanium Alloy

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ping-ze; XU Zhong; HE Zhi-yong; ZHANG Gao-hui

    2004-01-01

    Conventional titanium alloy may be ignited and burnt under high temperature, high pressure and high gas flow velocity condition. In order to avoid this problem, we have developed a new kind of burn-resistant titanium alloy-double glow plasma surface alloying burn-resistant titanium alloy. Alloying element Cr, Mo, Cu are induced into the Ti-6Al-4V and Ti-6.5Al-0.3Mo-l.5Zr-0.25Si substrates according to double glow discharge phenomenon, Ti-Cr ,Ti-Mo, Ti-Cu binary burn-resistant alloy layers are formed on the surface of Ti-6Al-4V and Ti-6.5Al-0.3Mo-l.5Zr-0.25Si alloys. The depth of the surface burn-resistant alloy layer can reach to above 200 microns and alloying element concentration can reach 90%.Burn-resistant property experiments reveal that if Cr concentration reach to 14%, Cu concentration reach to 12%, Mo concentration reach to 10% in the alloying layers, ignition and burn of titanium alloy can be effectively avoided.

  15. Double Glow Plasma Surface Alloyed Burn-resistant Titanium Alloy

    Institute of Scientific and Technical Information of China (English)

    ZHANGPing-ze; XUZhong; HEZhi-yong; ZHANGGao-hui

    2004-01-01

    Conventional titanium alloy may be ignited and burnt under high temperature, high pressure and high gas flow velocity condition. In order to avoid this problem, we have developed a new kind of burn-resistant titanium alloy-double glow plasma surface alloying burn-resistant titanium alloy. Alloying element Cr, Mo, Cu are induced into the Ti-6A1-4V and Ti-6.5Al-0.3Mo-1.5Zr-0.25Si substrates according to double glow discharge phenomenon, Ti-Cr ,Ti-Mo, Ti-Cu binary burn-resistant alloy layers are formed on the surface of Ti-6A1-4V and Ti-6.5Al-0.3Mo-1.5Zr-0.25Si alloys. The depth of the surface burn-resistant alloy layer can reach to above 200 microns and alloying element concentration can reach 90%. Burn-resistant property experiments reveal that if Cr concentration reach to 14%, Cu concentration reach to 12%, Mo concentration reach to 10% in the alloying layers, ignition and burn of titanium alloy can be effectively avoided.

  16. Pemilihan Bahan Alloy Untuk Konstruksi Gigitiruan

    OpenAIRE

    Medila Dahlan

    2008-01-01

    Pada kedokteran gigi bahan alloy sangat banyak digunakan dalam segala bidang. Dalam pembuatan konstruksi gigitiman biasanya digunakan alloy emas, alloy kobalt kromium, alloy nikei kromium dan alloy stainless steel sebagai komponen gigitiman kerangka logam serta pembuatan mahkota dan jembatan. Pemilihan bahan alloy dapat dilakukan berdasarkan sifat yang dimiiiki oleh masing-masing bahan alloy sehingga akan didapat hasil konstmksi gigitiruan yang memuaskan. Pada pemakaiannya didaiam mulut...

  17. Strip Casting of High Performance Structural Alloys

    Institute of Scientific and Technical Information of China (English)

    S S Park; J G Lee; Nack J Kim

    2004-01-01

    There exists a great need for the development of high performance alloys due to increasing demands for energy conservation and environmental protection. Application of strip casting shows a strong potential for the improvement of properties of existing alloys and also for the development of novel alloy systems with superior properties. The present paper reviews our Center's activities in the development of high performance alloys by strip casting. Examples include (1) Al alloys, (2) wrought Mg alloys, and (3) bulk metallic glass (BMG) alloys.

  18. Tungsten Alloy Outgassing Measurements

    CERN Document Server

    Rutherfoord, John P; Shaver, L

    1999-01-01

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

  19. Estudo do teor de alicina em alho

    OpenAIRE

    Mendes, Patrícia Alexandra Pinto

    2008-01-01

    A alicina (dialil-tiosulfinato) é o componente biológico mais activo no alho com inúmeras aplicações a nível da saúde, já conhecida desde décadas. Existem actualmente diversos métodos publicados para a determinação do teor de alicina no alho por HPLC e espectrofotometria. No entanto, os resultados mostram discordância no teor de alicina medido pelos vários métodos. Este estudo tem por objectivo a determinação do teor de alicina por métodos de HPLC e espectrofotometria; e com...

  20. O estudo do comportamento verbal no Brasil

    Directory of Open Access Journals (Sweden)

    Adriana Pineiro Fidalgo

    Full Text Available O presente trabalho realizou uma revisão histórica de dissertações de mestrado e teses de doutorado brasileiras sobre comportamento verbal, com base na proposta Skinneriana (1957/1992, produzidas entre 1968 e 2012. Foram investigados: a tipo de trabalho (dissertação ou tese, b universidades em que os trabalhos foram defendidos, c orientadores, d linha de pesquisa (básica, aplicada ou histórico-conceitual, e metodologia (descritiva ou experimental, e f temas de investigação. No total, 177 dissertações e 53 teses sobre comportamento verbal foram identificadas. Os resultados indicam que o estudo do comportamento verbal, no Brasil, estabeleceu-se como programa de pesquisa e cresceu ao longo dos anos.

  1. Estudo forense do sémen

    OpenAIRE

    Vaz, Josiana A.; Chelas, S.; S Santos; Queirós, B.; Gonçalves, A.; Pereira, M.; Alves, Maria José

    2009-01-01

    O estudo dos fluidos seminais na cena do crime está directamente ligado a crimes de índole sexual, sendo este de importância vital aquando da reconstrução do acto do crime e na identificação do agressor. O sémen é segregado pelos órgãos reprodutores masculinos, sendo o suporte líquido dos espermatozóides. Segundo Pinheiro (2008), este vestígio pode ser encontrado em manchas no vestuário, lençóis, almofadas, móveis, chão, veículos, tapetes, entre outros. O sémen, antes de secar, possui um o...

  2. Pareto-optimal alloys

    DEFF Research Database (Denmark)

    Bligaard, Thomas; Johannesson, Gisli Holmar; Ruban, Andrei;

    2003-01-01

    and the cost. In this letter we present a database consisting of the lattice parameters, bulk moduli, and heats of formation for over 64 000 ordered metallic alloys, which has been established by direct first-principles density-functional-theory calculations. Furthermore, we use a concept from economic theory...

  3. Alloy catalyst material

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a novel alloy catalyst material for use in the synthesis of hydrogen peroxide from oxygen and hydrogen, or from oxygen and water. The present invention also relates to a cathode and an electrochemical cell comprising the novel catalyst material, and the process use...

  4. Shape Memory Alloy Actuator

    Science.gov (United States)

    Baumbick, Robert J. (Inventor)

    2002-01-01

    The present invention discloses and teaches a unique, remote optically controlled micro actuator particularly suitable for aerospace vehicle applications wherein hot gas, or in the alternative optical energy, is employed as the medium by which shape memory alloy elements are activated. In gas turbine powered aircraft the source of the hot gas may be the turbine engine compressor or turbine sections.

  5. The in-situ Ti alloying of aluminum alloys and its application in A356 alloys

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    This research has investigated the in-situ Ti alloying of aluminum alloys and its application to A356 alloys and wheels through the evaluation of microstructure and mechanical properties, The results showed that stable titanium content can be obtained by adding a small quantity of TiO2 into electrolyte of pure aluminum. Under this approach, a greater than 95% absorptivity of titanium was achieved, and the microstructure of the specimens was changed to fine equiaxed grains from coarse columnar grains in the pure aluminum. In comparison with the tradition A356 alloys and wheels, the corresponding microstructure in the testing A356 alloys and wheels was finer. Although the tensile strength was similar between the testing and the tradition A356 alloys and wheels, the ductility of the former (testing) is superior to that of the later (tradition), leading to an excellent combination of strength and ductility from the testing alloys and wheels.

  6. The in-situ Ti alloying of aluminum alloys and its application in A356 alloys

    Directory of Open Access Journals (Sweden)

    Zongxia LIU

    2005-05-01

    Full Text Available This research has investigated the in-situ Ti alloying of aluminum alloys and its application to A356 alloys and wheels through the evaluation of microstructure and mechanical properties. The results showed that stable titanium content can be obtained by adding a small quantity of TiO2 into electrolyte of pure aluminum. Under this approach, a greater than 95% absorptivity of titanium was achieved, and the microstructure of the specimens was changed to fineequiaxed grains from coarse columnar grains in the pure aluminum. In comparison with the tradition A356 alloys and wheels, the corresponding microstructure in the testing A356 alloys and wheels was finer. Although the tensile strength was similar between the testing and the tradition A356 alloys and wheels, the ductility of the former (testing is superior to that of the later (tradition, leading to an excellent combination of strength and ductility from the testing alloys and wheels.

  7. Advanced ordered intermetallic alloy deployment

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.T.; Maziasz, P.J.; Easton, D.S. [Oak Ridge National Lab., TN (United States)

    1997-04-01

    The need for high-strength, high-temperature, and light-weight materials for structural applications has generated a great deal of interest in ordered intermetallic alloys, particularly in {gamma}-based titanium aluminides {gamma}-based TiAl alloys offer an attractive mix of low density ({approximately}4g/cm{sup 3}), good creep resistance, and high-temperature strength and oxidation resistance. For rotating or high-speed components. TiAl also has a high damping coefficient which minimizes vibrations and noise. These alloys generally contain two phases. {alpha}{sub 2} (DO{sub 19} structure) and {gamma} (L 1{sub 0}), at temperatures below 1120{degrees}C, the euticoid temperature. The mechanical properties of TiAl-based alloys are sensitive to both alloy compositions and microstructure. Depending on heat-treatment and thermomechanical processing, microstructures with near equiaxed {gamma}, a duplex structure (a mix of the {gamma} and {alpha}{sub 2} phases) can be developed in TiAl alloys containing 45 to 50 at. % Al. The major concern for structural use of TiAl alloys is their low ductility and poor fracture resistance at ambient temperatures. The purpose of this project is to improve the fracture toughness of TiAl-based alloys by controlling alloy composition, microstructure and thermomechanical treatment. This work is expected to lead to the development of TiAl alloys with significantly improved fracture toughness and tensile ductility for structural use.

  8. Tungsten carbide laser alloying of a low alloyed steel

    Science.gov (United States)

    Cojocaru, Mihai; Taca, Mihaela

    1996-10-01

    Laser alloying is a way to change the composition of metal surfaces in order to improve their corrosion-resistance, high-temperature strength and hardness. The results of a structural and phase analysis of a tungsten carbide based surface layer prepared by laser alloying of a low carbon steel substrate are presented. Structure, phase composition and microhardness of surface alloyed layers have been investigated. The surface of the samples exhibited a thin layer with a different chemical and phase composition. An increase in alloyed surface hardness and wear-resistance was observed.

  9. Filler metal alloy for welding cast nickel aluminide alloys

    Science.gov (United States)

    Santella, M.L.; Sikka, V.K.

    1998-03-10

    A filler metal alloy used as a filler for welding cast nickel aluminide alloys contains from about 15 to about 17 wt. % chromium, from about 4 to about 5 wt. % aluminum, equal to or less than about 1.5 wt. % molybdenum, from about 1 to about 4.5 wt. % zirconium, equal to or less than about 0.01 wt. % yttrium, equal to or less than about 0.01 wt. % boron and the balance nickel. The filler metal alloy is made by melting and casting techniques such as are melting the components of the filler metal alloy and cast in copper chill molds. 3 figs.

  10. Filler metal alloy for welding cast nickel aluminide alloys

    Energy Technology Data Exchange (ETDEWEB)

    Santella, Michael L. (Knoxville, TN); Sikka, Vinod K. (Oak Ridge, TN)

    1998-01-01

    A filler metal alloy used as a filler for welding east nickel aluminide alloys contains from about 15 to about 17 wt. % chromium, from about 4 to about 5 wt. % aluminum, equal to or less than about 1.5 wt. % molybdenum, from about 1 to about 4.5 wt. % zirconium, equal to or less than about 0.01 wt. % yttrium, equal to or less than about 0.01 wt. % boron and the balance nickel. The filler metal alloy is made by melting and casting techniques such as are melting the components of the filler metal alloy and east in copper chill molds.

  11. Materials data handbook, Inconel alloy 718

    Science.gov (United States)

    Sessler, J.; Weiss, V.

    1967-01-01

    Materials data handbook on Inconel alloy 718 includes data on the properties of the alloy at cryogenic, ambient, and elevated temperatures and other pertinent engineering information required for the design and fabrication of components and equipment utilizing this alloy.

  12. SINTERED REFRACTORY TUNGSTEN ALLOYS. Gesinterte hochschmelzende wolframlegierungen

    Energy Technology Data Exchange (ETDEWEB)

    Kieffer, R.; Sedlatschek, K.; Braun, H.

    1971-12-15

    Dependence of the melting point of the refractory metals on their positions in the periodic system - alloys of tungsten with other refractory metals - sintering of the alloys - processing of the alloys - technological properties.

  13. High-temperature Titanium Alloys

    Directory of Open Access Journals (Sweden)

    A.K. Gogia

    2005-04-01

    Full Text Available The development of high-temperature titanium alloys has contributed significantly to the spectacular progress in thrust-to-weight ratio of the aero gas turbines. This paper presents anoverview on the development of high-temperature titanium alloys used in aero engines and potential futuristic materials based on titanium aluminides and composites. The role of alloychemistry, processing, and microstructure, in determining the mechanical properties of titanium alloys is discussed. While phase equilibria and microstructural stability consideration haverestricted the use of conventional titanium alloys up to about 600 "C, alloys based on TiPl (or,, E,AINb (0, TiAl (y, and titaniumltitanium aluminides-based composites offer a possibility ofquantum jump in the temperature capability of titanium alloys.

  14. ESTUDO PROSPECTIVO SOBRE ENCAPSULAMENTO DE COMPOSTOS BIOATIVOS

    Directory of Open Access Journals (Sweden)

    Larissa Assunção

    2014-12-01

    Full Text Available Com o advento da nanotecnologia, houve o desenvolvimento de técnicas envolvendo processamento, fabricação e aplicação de estruturas, com forma e tamanho controlados, sendo que na indústria de alimentos, estas formulações, tanto na faixa micrométrica como nanométrica, vêm sendo utilizadas com o objetivo de favorecer o produto final. Tendo em vista a importância tecnológica dessa técnica e do grande interesse nacional e internacional, principalmente no ramo da indústria alimentícia, sobre os benefícios do encapsulamento, o presente estudo prospectivo teve como objetivo avaliar o panorama mundial relativo ao tema em questão, correlacionando-o com os documentos de patentes depositados. Para tanto, realizou-se uma pesquisa das patentes na base de dados europeia Espacenet®, utilizando os descritores do tema em estudo associados aos códigos de classificação. As informações encontradas foram compiladas em gráficos e discutidas. Pôde-se observar que o maior número de patentes referiu-se ao código A23L1/00 - alimentos ou produtos alimentícios: a sua preparação ou tratamento e houve um crescimento exponencial em relação ao depósito de patentes nos últimos 10 anos, sendo os Estados Unidos o país líder em número de patentes depositadas (60%. A Firmenich e CIE lidera o ranking com mais patentes depositadas. Em relação à área de atuação, predomina a indústria alimentícia (69%. No que diz respeito ao Brasil, o país aparece com apenas 1 patente detentora desta tecnologia, sendo um número bastante reduzido o que mostra a falta de incentivo neste setor. Diante dos resultados obtidos, concluiu-se que, apesar de ser uma tecnologia recente, observa-se uma tendência ao crescimento de depósito de patentes.

  15. Porosity of porous Al alloys

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Two porosity models of porous Al alloys with different pore types (ball and polygon shape) were established. The experimental results coincide well with theoretical computations. The porosity of Al alloys (Prc) consists of three parts, porosity caused by preform particles (Prp), additional porosity (Pra), and porosity caused by solidification shrinkage (Prs). Prp is the main part of Prc while Pra is the key for fabricating porous Al alloys successfully in spite of its little contribution to Prc.

  16. Multicomponent and High Entropy Alloys

    Directory of Open Access Journals (Sweden)

    Brian Cantor

    2014-08-01

    Full Text Available This paper describes some underlying principles of multicomponent and high entropy alloys, and gives some examples of these materials. Different types of multicomponent alloy and different methods of accessing multicomponent phase space are discussed. The alloys were manufactured by conventional and high speed solidification techniques, and their macroscopic, microscopic and nanoscale structures were studied by optical, X-ray and electron microscope methods. They exhibit a variety of amorphous, quasicrystalline, dendritic and eutectic structures.

  17. RUDOLF LABAN, A COREOLOGIA E OS ESTUDOS COREOLÓGICOS

    OpenAIRE

    Mota, Julio

    2012-01-01

    Este trabalho visa examinar como a necessidade de Laban conhecer as leis que regem o movimento humano o levou ao desenvolvimento de um método científico de estudo a que ele chamou de Coreologia. E de como a necessidade de aplicar o método coreológico, de maneira específica à Dança, conduziu ao surgimento de uma área específica de estudos, denominada Estudos Coreológicos. Este processo é aqui analisado através de um breve resumo biográfico de Laban. Essa biografia mostra como as in...

  18. Duct and cladding alloy

    Science.gov (United States)

    Korenko, Michael K.

    1983-01-01

    An austenitic alloy having good thermal stability and resistance to sodium corrosion at 700.degree. C. consists essentially of 35-45% nickel 7.5-14% chromium 0.8-3.2% molybdenum 0.3-1.0% silicon 0.2-1.0% manganese 0-0.1% zirconium 2.0-3.5% titanium 1.0-2.0% aluminum 0.02-0.1% carbon 0-0.01% boron and the balance iron.

  19. Shape memory alloy actuator

    Science.gov (United States)

    Varma, Venugopal K.

    2001-01-01

    An actuator for cycling between first and second positions includes a first shaped memory alloy (SMA) leg, a second SMA leg. At least one heating/cooling device is thermally connected to at least one of the legs, each heating/cooling device capable of simultaneously heating one leg while cooling the other leg. The heating/cooling devices can include thermoelectric and/or thermoionic elements.

  20. Analysis of laser alloyed surfaces

    Energy Technology Data Exchange (ETDEWEB)

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

    1981-04-01

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

  1. Estudo retrospectivo de latrodectismo na Bahia, Brasil

    Directory of Open Access Journals (Sweden)

    Rejâne Maria Lira-da-Silva

    1995-09-01

    Full Text Available O trabalho apresenta um estudo retrospectivo de setenta e sete casos de latrodectismo no Estado da Bahia, Brasil, de agosto de 1980 a julho de 1990. Os dados foram levantados nos livros de registro e arquivo de fichas do CIAVE. O agente etiológico em 28% dos acidentes aracnídeos foi a espécie L. curacaviensis e a maior incidência foi registrada no meio urbano (57%, em indivíduos do sexo masculino (70% e faixa etária de 10 a 29 anos (58%. Os principais sinais locais foram dor (56%, pápula eritematosa (21% e edema discreto (17%, e os sistêmicos foram dor em membros inferiores (29%, tremores e contraturas (29%, sudorese (28% parestesia em membros (21% e dor abdominal (17%. O tratamento foi sintomático em 67% dos casos e específico em 21%. O tempo de permanência hospitalar após o uso do soro antilatrodectus foi menor que 24 horas em 64% dos casos.

  2. Habilidades Sociais em Alcoolistas: Um Estudo Comparativo

    Directory of Open Access Journals (Sweden)

    Flaviane Bevilaqua Felicissimo

    Full Text Available RESUMO O presente estudo objetivou comparar o repertório de habilidades sociais (HS de dependentes e não dependentes de álcool a fim de verificar se um menor repertório de HS constitui uma característica dessa população. Foram entrevistados 123 alcoolistas e 114 usuários de serviços de saúde com baixo ou nenhum consumo de álcool, utilizando questionário sociodemográfico, Mini International Neuropsychiatric Interview e o Inventário de Habilidades Sociais. Os dados foram analisados quantitativamente e indicaram uma diferença significativa no repertório de HS, especificamente no fator de autocontrole da agressividade, indicando um pior desempenho dessa habilidade em alcoolistas. Os resultados sugerem que a avaliação dessa característica deva ser considerada no tratamento do alcoolismo e associada ao plano terapêutico.

  3. Paralisia periodica familiar: estudo de oito casos

    Directory of Open Access Journals (Sweden)

    José Lamartine De Assis

    1980-12-01

    Full Text Available Foram estudados oito pacientes com Paralisia Periódica Familiar sob os aspectos clínico, hidro-eletrolítico, eletrofisiológico, histológico e terapêutico. Houve predomínio significante em pacientes do sexo masculino. A idade média do início da moléstia foi de 15 anos. As manifestações clínicas foram concor-dantes com as referidas na literatura. Todos os pacientes tinham a forma hipocalêmica exceto um que evoluiu com hipercalemia. Alguns pacientes (21,4% tinham natremias no limite superior da normalidade enquanto em um número igual de pacientes as natremias estavam elevadas, o que sugeria liberação de aldosterona. Os achados eletrofisiológicos foram concordantes com os da literatura. O estudo histológico de músculos realizado em cinco pacientes foi normal em 30% deles e, naqueles com crises repetidas e freqüentes, foram encontradas atrofias de fibras musculares. Foram feitos tratamentos preventivos, e nos pacientes com hipocalemia foram administradas doses suplementares de potássio em solução aquosa de 10-25% diariamente.

  4. Aluminum alloy impact sparkling

    Directory of Open Access Journals (Sweden)

    M. Dudyk

    2008-08-01

    Full Text Available The cast machine parts are widely used in many branches of industry. A very important issue is gaining the appropriate knowledge relating to the application of castings in places of explosion risks including but not limited to mining, chemical industry and rescue works. A possibility of explosion risks occurrence following the impact sparkling of the cast metal parts is still not solved problem in scientific research. In relation to this issue, in this article, the results of the study are presented, and relating to the tendency to impact sparkling of the aluminium alloys used in machine building. On the grounds of the results obtained, it was demonstrated that the registered impact sparkles bunches of feathers from the analyzed alloys: AlSi7Mg, (AK7; AlSi9Mg, (AK9; AlSi6Cu4, (AK64 and AlSi11, (AK11 show significant differences between each other. The quantitative analysis of the temperature distribution and nuclei surface area performed on the example of the alloy AK9 (subjected to defined period of corrosion allows for the statement that they are dangerous in conditions of explosion risk. Following this fact, designers and users of machine parts made from these materials should not use them in conditions where the explosive mixtures occur.

  5. Oligocrystalline shape memory alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ueland, Stian M.; Chen, Ying; Schuh, Christopher A. [Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States)

    2012-05-23

    Copper-based shape memory alloys (SMAs) exhibit excellent shape memory properties in single crystalline form. However, when they are polycrystalline, their shape memory properties are severely compromised by brittle fracture arising from transformation strain incompatibility at grain boundaries and triple junctions. Oligocrystalline shape memory alloys (oSMAs) are microstructurally designed SMA structures in which the total surface area exceeds the total grain boundary area, and triple junctions can even be completely absent. Here it is shown how an oligocrystalline structure provides a means of achieving single crystal-like SMA properties without being limited by constraints of single crystal processing. Additionally, the formation of oSMAs typically involves the reduction of the size scale of specimens, and sample size effects begin to emerge. Recent findings on a size effect on the martensitic transformation in oSMAs are compared and a new regime of heat transfer associated with the transformation heat evolution in these alloys is discussed. New results on unassisted two-way shape memory and the effect of loading rate in oSMAs are also reported. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. ALLOY DESIGN AND PROPERTY EVALUATION OF TI ALLOY ...

    African Journals Online (AJOL)

    eobe

    The XRD analysis indicates that the crystal structure and mechanical properties are sensitive to Sn concentration. ... composites and ceramics, are being explored for use as biomaterials ... ALLOY OF TI-MO-NB-SN ALLOY FOR BIOMEDICAL APPLICATIONS ..... Almeida, C. A. “Least Square Unit Cell Refinement”. Program ...

  7. Radiation Effects in Refractory Alloys

    Science.gov (United States)

    Zinkle, Steven J.; Wiffen, F. W.

    2004-02-01

    In order to achieve the required low reactor mass per unit electrical power for space reactors, refractory alloys are essential due to their high operating temperature capability that in turn enables high thermal conversion efficiencies. One of the key issues associated with refractory alloys is their performance in a neutron irradiation environment. The available radiation effects data are reviewed for alloys based on Mo, W, Re, Nb and Ta. The largest database is associated with Mo alloys, whereas Re, W and Ta alloys have the least available information. Particular attention is focused on Nb-1Zr, which is a proposed cladding and structural material for the reactor in the Jupiter Icy Moons Orbiter (JIMO) project. All of the refractory alloys exhibit qualitatively similar temperature-dependent behavior. At low temperatures up to ~0.3TM, where TM is the melting temperature, the dominant effect of radiation is to produce pronounced radiation hardening and concomitant loss of ductility. The radiation hardening also causes a dramatic decrease in the fracture toughness of the refractory alloys. These low temperature radiation effects occur at relatively low damage levels of ~0.1 displacement per atom, dpa (~2×1024 n/m2, E>0.1 MeV). As a consequence, operation at low temperatures in the presence of neutron irradiation must be avoided for all refractory alloys. At intermediate temperatures (0.3 to 0.6 TM), void swelling and irradiation creep are the dominant effects of irradiation. The amount of volumetric swelling associated with void formation in refractory alloys is generally within engineering design limits (>10 dpa). Very little experimental data exist on irradiation creep of refractory alloys, but data for other body centered cubic alloys suggest that the irradiation creep will produce negligible deformation for near-term space reactor applications.

  8. Properties of laser alloyed surface layers on magnesium base alloys

    Energy Technology Data Exchange (ETDEWEB)

    Galun, R.; Weisheit, A.; Mordike, B.L. (Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). Inst. fuer Werkstoffkunde und Werkstofftechnik)

    1998-01-01

    The investigations have shown that laser surface alloying is a promising process to improve the wear and corrosion properties of magnesium base alloys without affecting the initial bulk properties like the low density. With an alloying element combination of aluminium and nickel the wear rate in the scratch test was reduced by 90% compared to untreated pure magnesium. Additionally the corrosion resistance was improved by laser alloying with this element combination. Because of distortion or crack formation in the case of large area treatments, the laser alloying should be limited to the treatment of smaller areas. In the near future this process could be an interesting alternative to surface coating or to a partially reinforcement with ceramic fibres or particles. (orig.)

  9. Estudo retrospectivo de latrodectismo na Bahia, Brasil

    Directory of Open Access Journals (Sweden)

    Rejâne Maria Lira-da-Silva

    1995-09-01

    Full Text Available O trabalho apresenta um estudo retrospectivo de setenta e sete casos de latrodectismo no Estado da Bahia, Brasil, de agosto de 1980 a julho de 1990. Os dados foram levantados nos livros de registro e arquivo de fichas do CIAVE. O agente etiológico em 28% dos acidentes aracnídeos foi a espécie L. curacaviensis e a maior incidência foi registrada no meio urbano (57%, em indivíduos do sexo masculino (70% e faixa etária de 10 a 29 anos (58%. Os principais sinais locais foram dor (56%, pápula eritematosa (21% e edema discreto (17%, e os sistêmicos foram dor em membros inferiores (29%, tremores e contraturas (29%, sudorese (28% parestesia em membros (21% e dor abdominal (17%. O tratamento foi sintomático em 67% dos casos e específico em 21%. O tempo de permanência hospitalar após o uso do soro antilatrodectus foi menor que 24 horas em 64% dos casos.This work is a retrospective study of latrodectism in the State of Bahia, Brazil, from August 1980 to July 1990. The data concerning the accidents were obtained from file cards at the Antivenom Information Center of Bahia (AVICB. Latrodectus curacavienis was the ethiologic agent identified in 28% of the arachnid accidents. The major incidence was registered in urban area (57% affecting men (70% more than women, with 10 to 29year-old age group (58%. Local pain (56%, erythematous papula (29% and light oedema (17% were the principal local symptoms. Pain in the limbs (29%, tremor and rigidities (29%, sweating (28%, limbs and arms paresthesia (21% and abdominal pain (17% were systemic ones. The treatment was mainly symptomatic (67% and antivenin serum was used in 21% of the cases. After serotherapy, 64% of the patients left the hospital within less than 24 hours.

  10. Valor do estudo citogenetico no transexualismo

    Directory of Open Access Journals (Sweden)

    P. H. Saldanha

    1976-09-01

    Full Text Available O transexualismo é caracterizado como uma entidade psiquiátrica, distinta do homossexualismo e travestismo, revendo-se suas manifestações sindrômicas. Discutem-se as duas principais causas etiológicas plausíveis do transexualismo, a saber: a hipótese psicoanalítica fundamentada na regressão psicossexual com estampagem da figura materna e o modelo neuro-endócrino que pressupõe alterações nos centros de identidade sexual do hipotámo. Com base nesta última explicação propõe-se, a exemplo do que parece ocorrer na síndrome de Morris, cujas células (XY não respondem ao efeito masculinizante da testosterona plasmática, que os transexuais devem possuir mosaicismo detectável ou críptico, quanto aos cromossomos sexuais, nos centros hipotalâmicos de identidade sexual que não respondem à secreção androgênica produzida pela gônada primitiva. Esta possibilidade explicaria a excessiva prevalência da síndrome entre homens, bem como a sua manifestação com feições típicas no sexo masculino e ainda a ocorrência esporádica da síndrome. O estudo citogenético revelou que a frequência (32% de mosaicismo quanto aos cromossomos sexuais em 25 transexuais é estatisticamente superior aos valores observados em 14 homossexuais e 40 controles normais, nos quais a proporção de mosaicismo é praticamente nula. Considera-se a possibilidade do critério cariotípico constituir valioso subsídio na diagnose da síndrome.

  11. Histerectomias: estudo retrospectivo de 554 casos

    Directory of Open Access Journals (Sweden)

    Eddie Fernando Cândido Murta

    Full Text Available OBJETIVO: A histerectomia é uma operação muito realizada, entretanto há poucos trabalhos na literatura nacional sobre suas indicações, técnica e complicações. O objetivo deste trabalho é avaliar estes procedimentos realizados na Disciplina de Ginecologia e Obstetrícia da Faculdade de Medicina do Triângulo Mineiro. MÉTODO: Estudo retrospectivo de 470 histerectomias abdominais e 84 vaginais foi conduzido analisando as indicações, tempo de cirurgia e internação, tipo de incisão e morbidez. RESULTADOS: As principais indicações foram o mioma uterino e o prolapso uterino para as histerectomias abdominais e vaginais, respectivamente. As complicações intra-operatórias aconteceram em 3,4% e as pós-operatórias em 2,4% do total de casos. Nenhuma diferença estatística foi encontrada no número de complicações em relação ao tipo de incisão (vertical ou transversal. O tempo de cirurgia e o de hospitalização foram estatisticamente maiores nas incisões verticais. A hemorragia foi a mais freqüente complicação intra-operatória e a infecção da incisão operatória foi a mais freqüente no pós-operatório. CONCLUSÕES: A histerectomia é um procedimento de baixo risco, no entanto, a realização de revisões sobre indicações e complicações, e a pesquisa de melhores técnicas cirúrgicas são necessárias para torná-la cada vez mais segura.

  12. Reticulossarcomas epidurais intraespinais: estudo de 34 casos

    Directory of Open Access Journals (Sweden)

    Lígia M. B. Coutinho

    1974-12-01

    Full Text Available Foi realizado um estudo de 34 casos de reticulossarcomas localizados no tecido epidural intraespinal. Assinala-se sua maior freqüência entre homens com mais de 50 anos, embora pacientes mais jovens possam ser acometidos, principalmente entre 15 e 29 anos. A distribuição segmentar dos tumores permite um diagnóstico diferencial, sendo a região torácica a sede mais freqüentes de sarcomas. O principal sintoma encontrado nos pacientes com reticulossarcoma foi a dor, do tipo radicular, que serve para diferenciar os tumores intra e extra-medulares, tendo sido de aparecimento precoce em 15 dos pacientes estudados, precedendo em muitos meses e até anos os demais sintomas. Classificou-se os tumores reticulohistiocitários epidurais do canal vertebral em três grupos, de acordo com seu aspecto tecidual e celular e, principalmente, com a presença e distribuição da reticulina. Relacionou-se o tempo de evolução desses tumores com seu aspecto histopatológico, chegando-se à conclusão que os tumores classificados no grupo III apresentam um período evolutivo maior que os demais, o que nos levou a pensar que crescem mais lentamente, apresentando, portanto, melhor prognóstico que os demais tipos, muito embora todos os tipos de reticulossarcomas possam apresentar um prognóstico mais favorável quando precocemente diagnosticados e tratados adequadamente.

  13. Estudos sobre a Esquistosomose em Pernambuco, Brasil

    Directory of Open Access Journals (Sweden)

    Aggeu Magalhães

    1940-01-01

    Full Text Available Os autores referem os resultados dos estudos sobre esquistosomose realisados, em Pernambuco, de Novembro de 1938 a Dezembro de 1939. Não se extendem em discussão, nem comentarios, tampouco, relacionam suas verificações com o que já foi relatado sobre o assunto em trabalhos nacionais e estrangeiros, pelo fato de que, não se trata de um resultado definitivo e sim de atividades que irão proseguir. Os estudos sistematicos em torno da endemia esquistosomica foram executados em duas localidades diversas pela população e pela situação geografica e ecologica. Pontezinha é uma povoação de 1200 habitantes localizada proximo a um conjunto de charcos e lagõas de agua dôce onde pululam caramujos do tipo olivaceus de Spix, e apresenta uma taxa de infestação de 21,4% para individuos do sexo masculino, e de 14,7% para os do sexo feminino. A distribuição por grupos de idade mostra que a incidencia cresce até o grupo de 16 a 20 anos de idade, quando atinge a percentagem de 37,8%, para decrescer em seguida. Em Vitoria a incidencia foi maior nos indivíduos do sexo feminino, atingindo a taxa de 41,4%, dando o sexo masculino a taxa de 36,9%. Por idade a percentagem maxima é atingida pelo grupo de 11 a 15 anos. Vitoria é uma cidade de 1500 habitantes, construida á margem do rio Tapacurá, onde se encontram numerosos caramujos do tipo centimetralis Lutz. A divergencia de incidencia corre por conta dos habitos da população e pela utilização que ela faz do rio, sendo maior em Vitoria porque a proximidade do rio facilita o uso de suas aguas para banho e serviços domesticos, condicionando este ultimo fato, a maior infestação das mulheres. O estudo da frequencia da infestação dos caramujos por cercarias de diversos trematodios, permite suspeitar uma relação inversa entre a taxa de infestação e o diametro maximo atingido pelos caramujos, parecendo este fato confirmar os trabalhos de Vianna Martins sobre a identidade dos hospedeiros

  14. Shape memory alloy thaw sensors

    Science.gov (United States)

    Shahinpoor, Mohsen; Martinez, David R.

    1998-01-01

    A sensor permanently indicates that it has been exposed to temperatures exceeding a critical temperature for a predetermined time period. An element of the sensor made from shape memory alloy changes shape when exposed, even temporarily, to temperatures above the Austenitic temperature of the shape memory alloy. The shape change of the SMA element causes the sensor to change between two readily distinguishable states.

  15. Electron Theory in Alloy Design

    CERN Document Server

    Pettifor, DG

    1992-01-01

    Presents recent developments in electron theory which have impacted upon the search for novel alloys with improved mechanical or magnetic properties. The ten chapters outline the ability of electron theory to make quantitative predictions (such as heats of formation, planar fault energies, shear moduli and magnetic anisotropy), and to provide simplifying concepts for understanding trends in alloy behaviour.

  16. Mo-Si alloy development

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-06-01

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

  17. Heat storage in alloy transformations

    Science.gov (United States)

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

    1981-01-01

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

  18. Wedlable nickel aluminide alloy

    Energy Technology Data Exchange (ETDEWEB)

    Santella, Michael L. (Knoxville, TN); Sikka, Vinod K. (Oak Ridge, TN)

    2002-11-19

    A Ni.sub.3 Al alloy with improved weldability is described. It contains about 6-12 wt % Al, about 6-12 wt % Cr, about 0-3 wt % Mo, about 1.5-6 wt % Zr, about 0-0.02 wt % B and at least one of about 0-0.15 wt % C, about 0-0.20 wt % Si, about 0-0.01 wt % S and about 0-0.30 wt % Fe with the balance being Ni.

  19. Estudos organizacionais, (descolonialidade e estudos da dependência: as contribuições da Cepal

    Directory of Open Access Journals (Sweden)

    Sergio Wanderley

    Full Text Available O objetivo deste artigo é (revisitar o conceito de dependência como categoria de investigação da (e a partir da América Latina, por meio de uma perspectiva histórica crítica descolonial, a fim de ampliar o espaço de debates em estudos organizacionais e promover alternativas à ordem neoliberal. Este ensaio terá como foco os estudos da dependência realizados pela Comissão Econômica para a América Latina e o Caribe (Cepal durante a década de 1950 e o início dos anos 1960. A perspectiva descolonial é um constructo teórico de autores latino-americanos que se consideram herdeiros da longa tradição do pensamento social crítico da região, na qual a teoria da dependência está inserida. As propostas dos autores da dependência confrontaram as principais teorias ortodoxas do Norte produzidas à época. A partir do conceito de centro-periferia, da denúncia de assimetrias nas relações entre essas regiões, do reconhecimento da interdependência entre desenvolvimento e subdesenvolvimento, o conceito de dependência foi sendo (reelaborado nas décadas de 1950 e 1960 por diversos autores latino-americanos como uma categoria de investigação da realidade da (e a partir da região. Essas investigações tinham por objetivo não somente elaborar constructos teóricos, mas, também, transformar a realidade por meio da criação de diversas organizações e instituições que deveriam servir ao propósito de superar o subdesenvolvimento. A denúncia da historicidade da situação de subdesenvolvimento desnudou o caráter de neutralidade do economicismo das teorias produzidas no Norte e promoveu um encontro teórico entre economia e política que muito tem a contribuir com a área dos estudos organizacionais.

  20. Galvanic cells including cobalt-chromium alloys.

    Science.gov (United States)

    Gjerdet, N R

    1980-01-01

    Galvanic cells may be created when dentures made of cobalt-chromium alloys are placed on teeth with metallic restorations. The power of such cells was evaluated in an in vitro galvanic using amalgams, gold alloy, and nickel-chromium alloys. The amalgams and one of the nickel-chromium alloys revealed high corrosion currents when placed in contact with cobalt-chromium alloy, the conventional amalgam showing the highest values. The gold alloy and another nickel-chromium alloy exhibited low corrosion currents and they were noble with respect to cobalt-chromium.

  1. ESTUDOS NUTRICIONAIS COM ARROZ (Oryza sativa, L.

    Directory of Open Access Journals (Sweden)

    Alfredo LAM-SÁNCHEZ

    2009-07-01

    Full Text Available

    RESUMO: Estudos com arroz (Oryza sativa, L. foram realizados a fim de determinar a variabilidade do teor de proteína em coleções de cultivares e a possibilidade de utilizar as camadas periféricas do grão na alimentação humana. Foram analisadas 626 linhagens e cultivares de arroz que mostraram uma variação quanto ao teor de proteína de 4.00 a 14.31 g/100 g de amostra. Para se extrair as camadas periféricas do grão, foi desenvolvida uma máquina experimental, que removia as camadas superficiais dos grãos de arroz integral (inteiros somente com a casca removida. Verificou-se que a quantidade de proteína do grão diminui de fora para dentro. O resíduo, que era constituído de grande parte de restos de endosperma com um teor protéico menor mas incluía o embrião, que é a primeira estrutura a se deslocar de grão no beneficiamento e contém proteínas, vitaminas, sais minerais e lípides, tinha um bom valor nutritivo. Desenvolveu-se também uma fórmula para alimentação infantil a partir da mistura de leite de vaca com arroz, com composição semelhante à do leite materno, a ser utilizada sob a forma de bebida ou mingau. Formulações com 40%-20% arroz + 60%-80% leite de vaca proporcionaram valores de Coeficiente de Eficiência Protéica (2,39 e 2,38, respectivamente que não diferiam estatisticamente do valor de 2,43 obtido na fórmula com 100% de leite de vaca. Seus preços foram 59% e 65% do obtido para o leite de vaca integral. PALAVRAS-CHAVE: Arroz; qualidade do grão; proteína; camadas periféricas; misturas arroz-leite; nutrição humana.

  2. Estudo de caso: disfonia psicogênica

    Directory of Open Access Journals (Sweden)

    Marcela Bergamini

    2015-02-01

    Full Text Available Disfonia funcional psicogênica possui relação com aspectos psicológicos. O tipo de voz, a articulação e a fluência são sensíveis às oscilações psicológicas. Uma voz em ajuste de falsete paralítico, caracterizada como uma voz de pitch extremamente agudo pode ser encontrada em casos de disfonias psicogênicas. Em qualquer quadro psicogênico é essencial um diagnóstico diferencial, a fim de viabilizar um tratamento fonoaudiológico e médico adequados e efetivos. O prognóstico de uma alteração psicogênica geralmente é bom. O quadro de disfonia psicogênica é mais comum no sexo feminino. O objetivo desse estudo é apresentar a evolução terapêutica de um indivíduo com disfonia psicogênica. A.J.O., 45 anos, sexo masculino, compareceu ao Ambulatório de Avaliação e Terapia de Voz encaminhado por médico otorrinolaringologista. Trouxe a queixa vocal "pela manhã a voz está perfeita, conforme o dia passa, a voz fica fina". Realizou avaliação fonoaudiológica em 18 de abril de 2013, com laudo médico de "mobilidade reduzida de prega vocal esquerda". Tratamento com técnica de sons disparadores, com modificação direta nos sintomas e evolução rápida. Demonstrou-se satisfeito com sua qualidade vocal. Em casos de suspeita de disfonias psicogênicas de conversão, devem-se descartar alterações orgânicas, sendo essencial uma avaliação fonoaudiológica que auxilie no diagnóstico diferencial e provas terapêuticas que incentivem o paciente.

  3. About Alloying of Aluminum Alloys with Transition Metals

    Science.gov (United States)

    Zakharov, V. V.

    2017-05-01

    An attempt is made to advance Elagin's principles of alloying of aluminum alloys with transition metals (TM) such as Mn, Cr, Zr, Ti, V with allowance for the ternary equilibrium and metastable Al - TM - TM phase diagrams. The key moments in the analysis of the phase diagrams are the curves (surfaces) of joint solubility of TM in aluminum, which bound the range of the aluminum solid solution. It is recommended to use combinations of such TM (two and more), the introduction of which into aluminum alloys widens the phase range of the aluminum solid solution.

  4. [Prosthetic dental alloys. 1].

    Science.gov (United States)

    Quintero Engelmbright, M A

    1990-11-01

    A wide variety of restoration materials for prosthetic odontology is now available to the dental surgeon, either of the covalent type (acrylic resins), metallic (alloys), ionic (porcelains), or a combination of them, as in the so-called composites, such as the composite resins, or as ceramics-metals mixtures. An example of the latter is a product called Miracle-Mix, a glass ionomere cement reinforced with an amalgam alloy. In those cases where the blend is done by a synterization process, the material is called Cermet. The above-listed alternatives clearly evidence day-to-day advances in odontology, with researchers and manufacturers engaged the world over in improving existing products or developing new ones to enrich the dentist's armamentarium. As a side effect of this constant renewal, those dentists who have failed to update their knowledge fall behind in their practice as they persist in using products they have known for years, and may be deceived by advertisements of too-often unreliable products. It is, therefore, important to be aware of available products and their latest improvements.

  5. [Prosthetic dental alloys (2)].

    Science.gov (United States)

    Quintero Englembright, M A

    1990-12-01

    A wide variety of restoration materials for prosthetic odontology is now available to the dental surgeon, either of the covalent type (acrylic resins), metallic (alloys), ionic (porcelains), or a combination of them, as in the so-called composites, such as the composite resins, or as ceramics-metals mixtures. An example of the latter is a product called Miracle-Mix, a glass ionomere cement reinforced with an amalgam alloy. In those cases where the blend is done by a synterization process, the material is called Cermet. The above-listed alternatives clearly evidence day-to-day advances in odontology, with researchers and manufacturers engaged the world over in improving existing products or developing new ones to enrich the dentist's armamentarium. As a side effect of this constant renewal, those dentists who have failed to update their knowledge fall behind in their practice as they persist in using products they have known for years, and may be deceived by advertisements of too-often unreliable products. It is, therefore, important to be aware of available products and their latest improvements.

  6. Density of Liquid Ni-Cr Alloy

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

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

  7. Mechanically Alloyed High Entropy Composite

    Science.gov (United States)

    Popescu, G.; Adrian, M. M.; Csaki, I.; Popescu, C. A.; Mitrică, D.; Vasile, S.; Carcea, I.

    2016-08-01

    In the last years high entropy alloys have been investigated due to their high hardness, high temperature stability and unusual properties that make these alloys to have significant interest. In comparison with traditional alloys that are based on two or three major elements, this new generation alloys consists at least of 5 principal elements, with the concentration between 5 and 35 at.%. The present paper reports synthesis of high entropy alloys (HEA) and high entropy composites (HEC) synthesized by mechanical alloying (MA). The equiatomic AlCrFeNiMn matrix was used for creating the HEA matrix, starting from elemental powders and as reinforcing material for composites was used pure graphite. The mechanical alloying process was carried out at different duration, in a high energy planetary ball mill, under argon atmosphere. The elemental powders alloying began after '5 hours of milling and was complete after 40 hours. The mechanical alloyed matrix and composite was pressed and heat treated under argon protection. The elemental powers were investigated for physical - technological properties, and by X-ray diffraction and scanning electron microscopy. Phase pressing operation was realized with a hydraulic press and the applied pressure was progressive. The sintering process was carried out at 850°C for 2 h. The X-ray diffraction revealed that the MA process resulted in solid solutions formation and also revealed body- centred cubic (BCC) and face-centred cubic (FCC) structures with average grain size around 40 nm. In addition, nanoscale particles were highlighted by scanning electron microscopy, as well as the homogeneity of the chemical composition of the matrix and composite that was confirmed by EDX microanalysis. It was noted that HEA matrix and HEA composites were processed with a high degree of compaction and with a quite large capacity of mixed powder densification (around 70%).

  8. Uma ferramenta para planejamento de estudos para concursos

    Directory of Open Access Journals (Sweden)

    Leonardo Pimentel

    2015-11-01

    Full Text Available De acordo com a constituição brasileira, a única forma de se tornar um empregado do governo é passar em um concurso público. O exame de conhecimento do cargo é um dos componentes mais importantes de um concurso. Estudar para esse exame é uma tarefa que requer planejamento. Um meio de obter um bom planejamento é construir uma grade de horários que relacione as matérias a serem estudadas com os respectivos horários disponíveis para o estudo. Esse tipo de problema se assemelha bastante à gerência de projetos, em que se procura estabelecer a distribuição das atividades ao longo do tempo disponível. Assim, torna-se interessante explorar a dinâmica de estudos para concursos como um projeto. O presente trabalho apresenta a ferramenta de apoio ao estudos - Passe-me, baseada no ciclo PDCA (do inglês, Plan-Do-Check-Act. Por se tratar de uma ferramenta web, o tempo de resposta para produzir uma grade de estudos é fundamental. A ferramenta faz uso de algoritmo genético para calcular a grade de horários priorizando a velocidade de resposta. A ferramenta foi avaliada em diferentes cenários de uso e obteve desempenho satisfatório durante a produção da grade de estudos.

  9. Modeling dissolution in aluminum alloys

    Science.gov (United States)

    Durbin, Tracie Lee

    2005-07-01

    Aluminum and its alloys are used in many aspects of modern life, from soda cans and household foil to the automobiles and aircraft in which we travel. Aluminum alloy systems are characterized by good workability that enables these alloys to be economically rolled, extruded, or forged into useful shapes. Mechanical properties such as strength are altered significantly with cold working, annealing, precipitation-hardening, and/or heat-treatments. Heat-treatable aluminum alloys contain one or more soluble constituents such as copper, lithium, magnesium, silicon and zinc that individually, or with other elements, can form phases that strengthen the alloy. Microstructure development is highly dependent on all of the processing steps the alloy experiences. Ultimately, the macroscopic properties of the alloy depend strongly on the microstructure. Therefore, a quantitative understanding of the microstructural changes that occur during thermal and mechanical processing is fundamental to predicting alloy properties. In particular, the microstructure becomes more homogeneous and secondary phases are dissolved during thermal treatments. Robust physical models for the kinetics of particle dissolution are necessary to predict the most efficient thermal treatment. A general dissolution model for multi-component alloys has been developed using the front-tracking method to study the dissolution of precipitates in an aluminum alloy matrix. This technique is applicable to any alloy system, provided thermodynamic and diffusion data are available. Treatment of the precipitate interface is explored using two techniques: the immersed-boundary method and a new technique, termed here the "sharp-interface" method. The sharp-interface technique is based on a variation of the ghost fluid method and eliminates the need for corrective source terms in the characteristic equations. In addition, the sharp-interface method is shown to predict the dissolution behavior of precipitates in aluminum

  10. Rapidly solidified aluminum alloy powder

    Energy Technology Data Exchange (ETDEWEB)

    Cho, S.S.; Chun, B.S.; Won, C.W.; Lee, B.S.; Kim, H.K.; Ryu, M. [Chungnam National Univ., Taejon (Korea, Republic of); Antolovich, S.D. [Washington State Univ., Pullman, WA (United States)

    1997-01-01

    Miniaturization and weight reduction are becoming increasingly important in the fabrication of vehicles. In particular, aluminum-silicon alloys are the logical choice for automotive parts such as pistons and cylinders liners because of their excellent wear resistance and low coefficient of thermal expansion. However, it is difficult to produce aluminum-silicon alloys with silicon contents greater than 20 wt% via ingot metallurgy, because strength is drastically reduced by the coarsening of primary silicon particles. This article describes an investigation of rapid solidification powder metallurgy techniques developed in an effort to prevent coarsening of the primary silicon particles in aluminum-silicon alloys.

  11. Alloying and Casting Furnace for Shape Memory Alloys Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The concept in the proposed project is to create a melting, alloying and casting furnace for the processing titanium based SMA using cold crucible techniques. The...

  12. Alloy design for intrinsically ductile refractory high-entropy alloys

    Science.gov (United States)

    Sheikh, Saad; Shafeie, Samrand; Hu, Qiang; Ahlström, Johan; Persson, Christer; Veselý, Jaroslav; Zýka, Jiří; Klement, Uta; Guo, Sheng

    2016-10-01

    Refractory high-entropy alloys (RHEAs), comprising group IV (Ti, Zr, Hf), V (V, Nb, Ta), and VI (Cr, Mo, W) refractory elements, can be potentially new generation high-temperature materials. However, most existing RHEAs lack room-temperature ductility, similar to conventional refractory metals and alloys. Here, we propose an alloy design strategy to intrinsically ductilize RHEAs based on the electron theory and more specifically to decrease the number of valence electrons through controlled alloying. A new ductile RHEA, Hf0.5Nb0.5Ta0.5Ti1.5Zr, was developed as a proof of concept, with a fracture stress of close to 1 GPa and an elongation of near 20%. The findings here will shed light on the development of ductile RHEAs for ultrahigh-temperature applications in aerospace and power-generation industries.

  13. Laser surface alloying of aluminium-transition metal alloys

    Directory of Open Access Journals (Sweden)

    Almeida, A.

    1998-04-01

    Full Text Available Laser surface alloying has been used as a tool to produce hard and corrosion resistant Al-transition metal (TM alloys. Cr and Mo are particularly interesting alloying elements to produce stable highstrength alloys because they present low diffusion coefficients and solid solubility in Al. To produce Al-TM surface alloys a two-step laser process was developed: firstly, the material is alloyed using low scanning speed and secondly, the microstructure is modified by a refinement step. This process was used in the production of Al-Cr, Al-Mo and Al-Nb surface alloys by alloying Cr, Mo or Nb powder into an Al and 7175 Al alloy substrate using a CO2 laser. This paper presents a review of the work that has been developed at Instituto Superior Tecnico on laser alloying of Al-TM alloys, over the last years.

    En el presente trabajo se estudia la aleación superficial mediante láser de aluminio con metales de transición. El cromo y el molibdeno son particularmente interesantes porque producen aleaciones de alta resistencia y por el bajo coeficiente de difusión y solución sólida en aluminio. Para producir estas aleaciones se ha seguido un procedimiento desarrollado en dos partes. En primer lugar, el material se alea usando una baja velocidad de procesado y en segundo lugar la estructura se modifica mediante un refinamiento posterior. Este procedimiento se ha empleado en la producción de aleaciones Al-Cr, Al-Mo y Al-Nb mediante aleación con láser de CO2 de polvos de Cr, Mo o Nb en aluminio y la aleación 7175. Este trabajo es una revisión del desarrollado en el Instituto Superior Técnico de Lisboa en los últimos años.

  14. Desenvolvimento da Tanatologia: estudos sobre a morte e o morrer

    Directory of Open Access Journals (Sweden)

    Maria Julia Kovács

    2008-12-01

    Full Text Available Este artigo discute os principais temas e pesquisas na área da Tanatologia, estudos sobre a morte e o morrer. São apresentados os autores pioneiros que escreveram as primeiras obras de sistematização da Tanatologia entre os quais: Herman Feifel, Robert Kastenbaum e Elizabeth Kübler-Ross, e os principais temas de estudo: luto, violência e guerra, a morte e a TV, cuidados a pacientes gravemente enfermos, além da formação de profissionais da área de saúde e educação para lidar com pessoas vivendo situações de perdas e morte. São feitas propostas de estudos para o futuro desenvolvimento da Tanatologia em nosso país.

  15. BASES DO COMPROMETIMENTO ORGANIZACIONAL: UM ESTUDO COMPARATIVO EM EMPRESAS JUNIORES

    Directory of Open Access Journals (Sweden)

    Maria José da Silva Feitosa

    2013-04-01

    Full Text Available Nos últimos anos intensificaram-se os estudos referentes às bases do comprometimento organizacional, contempladas no modelo Meyer e Allen. Nessa perfectiva, o presente estudo objetiva verificar as bases afetiva, normativa e instrumental em duas empresas de consultoria. Para tanto, foi realizada uma pesquisa descritiva, de abordagem quantitativa. Os resultados apontam que a base afetiva se destacou em ambas as empresas, tanto em uma análise por gênero, quanto em uma perspectiva geral. Esse resultado pode estar relacionado à possibilidade de que os estudantes que ingressam em empresas juniores se entusiasmem com a oportunidade de aplicar seus conhecimentos e se comprometam de forma afetiva com a organização. No entanto, para testar essa relação sugere-se a realização de novos estudos.

  16. Metallic alloy stability studies

    Science.gov (United States)

    Firth, G. C.

    1983-01-01

    The dimensional stability of candidate cryogenic wind tunnel model materials was investigated. Flat specimens of candidate materials were fabricated and cryo-cycled to assess relative dimensional stability. Existing 2-dimensional airfoil models as well as models in various stages of manufacture were also cryo-cycled. The tests indicate that 18 Ni maraging steel offers the greatest dimensional stability and that PH 13-8 Mo stainless steel is the most stable of the stainless steels. Dimensional stability is influenced primarily by metallurgical transformations (austenitic to martensitic) and manufacturing-induced stresses. These factors can be minimized by utilization of stable alloys, refinement of existing manufacturing techniques, and incorporation of new manufacturing technologies.

  17. Lead telluride alloy thermoelectrics

    Directory of Open Access Journals (Sweden)

    Aaron D. LaLonde

    2011-11-01

    Full Text Available The opportunity to use solid-state thermoelectrics for waste heat recovery has reinvigorated the field of thermoelectrics in tackling the challenges of energy sustainability. While thermoelectric generators have decades of proven reliability in space, from the 1960s to the present, terrestrial uses have so far been limited to niche applications on Earth because of a relatively low material efficiency. Lead telluride alloys were some of the first materials investigated and commercialized for generators but their full potential for thermoelectrics has only recently been revealed to be far greater than commonly believed. By reviewing some of the past and present successes of PbTe as a thermoelectric material we identify the issues for achieving maximum performance and successful band structure engineering strategies for further improvements that can be applied to other thermoelectric materials systems.

  18. Emissivity measurements on aeronautical alloys

    Energy Technology Data Exchange (ETDEWEB)

    Campo, L. del, E-mail: leire.del-campo@cnrs-orleans.f [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Perez-Saez, R.B., E-mail: raul.perez@ehu.e [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Instituto de Sintesis y Estudio de Materiales, Universidad del Pais Vasco, Apdo. 644, 48080 Bilbao (Spain); Gonzalez-Fernandez, L. [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Esquisabel, X.; Fernandez, I. [Industria de Turbo Propulsores, S.A., Planta de Zamudio, Edificio 300, 48170 Zamudio, Bizkaia (Spain); Gonzalez-Martin, P. [Industria de Turbo Propulsores, S.A., Parque empresarial San Fernando, Avda. Castilla 2, 28830 San Fernando de Henares, Madrid (Spain); Tello, M.J. [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Instituto de Sintesis y Estudio de Materiales, Universidad del Pais Vasco, Apdo. 644, 48080 Bilbao (Spain)

    2010-01-21

    The emissivity of three Ni and Co based aeronautical alloys is analyzed in this paper. These alloys are employed in high temperature environments whenever good corrosion resistance, high temperature resistance and high strength are essential. Thus, apart from the aeronautical industry, these alloys are also used in other technological applications, as for example, aerospace, nuclear reactors, and tooling. The results in this paper extend the emissivity data for these alloys available in the literature. Emissivity dependence on the radiation wavelength (2-22 {mu}m), sample temperature (200-650 {sup o}C) and emission angle (0-85{sup o}) has been investigated. In addition, the effect of surface finish and oxidation has also been taken into consideration. The data in this paper have several applications, as temperature measurement of a target by pyrometry, low observability of airplanes and thermal radiation heat transfer simulation in airplane nozzles or furnaces.

  19. Desenvolvimento da Tanatologia: estudos sobre a morte e o morrer

    OpenAIRE

    Maria Julia Kovács

    2008-01-01

    Este artigo discute os principais temas e pesquisas na área da Tanatologia, estudos sobre a morte e o morrer. São apresentados os autores pioneiros que escreveram as primeiras obras de sistematização da Tanatologia entre os quais: Herman Feifel, Robert Kastenbaum e Elizabeth Kübler-Ross, e os principais temas de estudo: luto, violência e guerra, a morte e a TV, cuidados a pacientes gravemente enfermos, além da formação de profissionais da área de saúde e educação para lidar com pessoas vivend...

  20. Estudo patográfico de Fernando Pessoa

    OpenAIRE

    2009-01-01

    Fernando Pessoa, incontestavelmente um dos maiores gênios da literatura universal, é objeto deste estudo patográfico. Através da análise de sua biografia e obra, os autores buscam delinear seus perfis psicológico e psicopatológico e caracterizar uma associação entre sua evidente bipolaridade e seu padrão criativo. Os dados do estudo revelam claramente um componente bipolar e sugerem haver influência de seu humor de base sobre a atividade literária, quanto ao conteúdo, número de po...

  1. Desenvolvimento da Tanatologia: estudos sobre a morte e o morrer

    OpenAIRE

    Maria Julia Kovács

    2008-01-01

    Este artigo discute os principais temas e pesquisas na área da Tanatologia, estudos sobre a morte e o morrer. São apresentados os autores pioneiros que escreveram as primeiras obras de sistematização da Tanatologia entre os quais: Herman Feifel, Robert Kastenbaum e Elizabeth Kübler-Ross, e os principais temas de estudo: luto, violência e guerra, a morte e a TV, cuidados a pacientes gravemente enfermos, além da formação de profissionais da área de saúde e educação para lidar com pessoas vivend...

  2. Ni{sub 3}Al aluminide alloys

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.T.

    1993-10-01

    This paper provides a brief review of the recent progress in research and development of Ni{sub 3}Al and its alloys. Emphasis has been placed on understanding low ductility and brittle fracture of Ni{sub 3}Al alloys at ambient and elevated temperatures. Recent studies have resulted in identifying both intrinsic and extrinsic factors governing the fracture behavior of Ni{sub 3}Al alloys. Parallel efforts on alloy design using physical metallurgy principles have led to properties for structural use. Industrial interest in these alloys is high, and examples of industrial involvement in processing and utilization of these alloys are briefly mentioned.

  3. Propostas para o estudo dos protestantismos ibéricos

    OpenAIRE

    Afonso, José António

    2004-01-01

    A propósito da edição da obra “Las minorias religiosas en España y Portugal: passado y presente”, número monográfico da revista “Anales de Historia Contemporanea” (Universidade de Múrcia), o Autor elenca algumas propostas para o estudo dos protestantismos ibéricos.

  4. ACREDITAÇÃO HOSPITALAR: UM ESTUDO DE CASO

    Directory of Open Access Journals (Sweden)

    Felipe Antunes

    2005-06-01

    Full Text Available Este artigo aborda a qualidade e acreditação hospitalar através do Manual das Organizações Prestadoras de Serviços Hospitalares, desenvolvido pela Organização Nacional de Acreditação (ONA. O objetivo geral deste trabalho é avaliar o processo de acreditação, identificando dificuldades e benefícios advindos da implantação deste  Manual. Após a realização de uma revisão bibliográfica sobre qualidade em hospitais e normas da qualidade aplicáveis a hospitais, é feita uma análise crítica teórica do Manual das Organizações Prestadoras de Serviços Hospitalares. Tal análise crítica inclui um estudo comparativo entre os requisitos do Manual e da norma NBR ISO 9001/2000. A seguir, a análise teórica é complementada através de um estudo de caso contemplando a implantação do Manual junto a um hospital de grande porte. Finalmente, são apresentadas as conclusões, baseadas tanto no estudo teórico como no estudo prático.

  5. Pragmatismo e os pragmáticos nos estudos organizacionais

    Directory of Open Access Journals (Sweden)

    Francis Kanashiro Meneghetti

    Full Text Available O objetivo central deste ensaio teórico é avaliar as contribuições do pragmatismo nos Estudos Organizacionais e, os específicos, avaliar se as contribuições teóricas de Charles Peirce e John Dewey possibilitam afirmar o pragmatismo como senso comum, ciência ou teoria do conhecimento; analisar as contribuições - possibilidadese limites - do pragmatismo como conhecimento científico; compreender os percursos do pragmatismo nos Estudos Organizacionais. Chaga-se a conclusão de que ser pragmático é diferente de conceber estudos articulados no campo epistemológico do pragmatismo. O sujeito pragmático vê na sua utilidade e na necessidade deação, o ponto de tensão que coloca em dúvida a veracidade dos pressupostos do pragmatismo como ciência. O que ocorre nos Estudos Organizacionais éa conversão do pragmatismo como conhecimento científico emsubordinação irracional à utilidade e à ação prática, sobretudo, no campo da economia, da política, da ciência, da cultura, da educação, e assim por diante.

  6. Magnesium-based biodegradable alloys: Degradation, application, and alloying elements.

    Science.gov (United States)

    Pogorielov, Maksym; Husak, Eugenia; Solodivnik, Alexandr; Zhdanov, Sergii

    2017-03-01

    In recent years, the paradigm about the metal with improved corrosion resistance for application in surgery and orthopedy was broken. The new class of biodegradable metal emerges as an alternative for biomedical implants. These metals corrode gradually with an appropriate host response and release of corrosion products. And it is absolutely necessary to use essential metals metabolized by hosting organism with local and general nontoxic effect. Magnesium serves this aim best; it plays the essential role in body metabolism and should be completely excreted within a few days after degradation. This review summarizes data from Mg discovery and its first experimental and clinical application of modern concept of Mg alloy development. We focused on biodegradable metal application in general surgery and orthopedic practice and showed the advantages and disadvantages Mg alloys offer. We focused on methods of in vitro and in vivo investigation of degradable Mg alloys and correlation between these methods. Based on the observed data, a better way for new alloy pre-clinical investigation is suggested. This review analyzes possible alloying elements that improve corrosion rate, mechanical properties, and gives the appropriate host response.

  7. Kinetics of aluminum lithium alloys

    Science.gov (United States)

    Pletcher, Ben A.

    2009-12-01

    Aluminum lithium alloys are increasingly used in aerospace for their high strength-to-weight ratio. Additions of lithium, up to 4.2 wt% decrease the alloy density while increasing the modulus and yield strength. The metastable, second phase Al3Li or delta' is intriguing, as it remains spherical and coherent with the matrix phase, alpha, well into the overaged condition. Small interfacial strain energy allows these precipitates to remain spherical for volume fractions (VV ) of delta' less than 0.3, making this alloy system ideal for investigation of late-stage coarsening phenomena. Experimental characterization of three binary Al-Li alloys are presented as a critical test of diffusion screening theory and multi-particle diffusion simulations. Quantitative transmission electron microscopy is used to image the precipitates directly using the centered dark-field technique. Images are analyzed autonomously within a novel Matlab function that determines the center and size of each precipitate. Particle size distribution, particle growth kinetics, and maximum particle size are used to track the precipitate growth and correlate with the predictions of screening theory and multi-particle diffusion simulations. This project is the first extensive study of Al-Li alloys, in over 25 years, applying modern transmission electron microscopy and image analysis techniques. Previous studies sampled but a single alloy composition, and measured far fewer precipitates. This study investigates 3 alloys with volume fractions of the delta precipitates, VV =0.1-0.27, aged at 225C for 1 to 10 days. More than 1000 precipitates were sampled per aging time, creating more statistically significant data. Experimental results are used to test the predictions based on diffusion screening theory and multi-particle aging simulations. (Full text of this dissertation may be available via the University of Florida Libraries web site. Please check http://www.uflib.ufl.edu/etd.html)

  8. Alloy hardening and softening in binary molybdenum alloys as related to electron concentration

    Science.gov (United States)

    Stephens, J. R.; Witzke, W. R.

    1972-01-01

    An investigation was conducted to determine the effects of alloy additions of hafnium, tantalum, tungsten, rhenium, osmium, iridium, and platinum on hardness of molybdenum. Special emphasis was placed on alloy softening in these binary molybdenum alloys. Results showed that alloy softening was produced by those elements having an excess of s+d electrons compared to molybdenum, while those elements having an equal number or fewer s+d electrons that molybdenum failed to produce alloy softening. Alloy softening and alloy hardening can be correlated with the difference in number of s+d electrons of the solute element and molybdenum.

  9. Alloys developed for high temperature applications

    Science.gov (United States)

    Basuki, Eddy Agus; Prajitno, Djoko Hadi; Muhammad, Fadhli

    2017-01-01

    Alloys used for high temperatures applications require combinations of mechanical strength, microstructural stability and corrosion/oxidation resistance. Nickel base superalloys have been traditionally the prime materials utilized for hot section components of aircraft turbine engines. Nevertheless, due to their limited melting temperatures, alloys based on intermetallic compounds, such as TiAl base alloys, have emerged as high temperature materials and intensively developed with the main aim to replace nickel based superalloys. For applications in steam power plants operated at lower temperatures, ferritic high temperature alloys still attract high attention, and therefore, development of these alloys is in progress. This paper highlights the important metallurgical parameters of high temperature alloys and describes few efforts in the development of Fe-Ni-Al based alloys containing B2-(Fe,Ni)Al precipitates, oxide dispersion strengthening (ODS) ferritic steels and titanium aluminide based alloys include important protection system of aluminide coatings.

  10. Effects of various Mg-Sr master alloys on microstructural refinement of ZK60 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The effects of various Mg-Sr master alloys (conventional as-cast, rapidly-solidified, rolled and solutionized) on microstructural refinement of ZK60 magnesium alloy were investigated. The results indicate that the refinement efficiency of various Mg-Sr master alloys in ZK60 alloy is different. The rolled Mg-Sr master alloy is found to have relatively higher refinement efficiency than the conventional as-cast, solutionized and rapidly-solidified Mg-Sr master alloys. After being treated with the rolled Mg-Sr master alloy, the ZK60 alloy obtains the minimum average grain size of 33 μm. The difference of various Mg-Sr master alloys in refinement efficiency might be related to the initial microstructure change of various Mg-Sr master alloys.

  11. Laser cladding of titanium alloy coating on titanium aluminide alloy substrate

    Institute of Scientific and Technical Information of China (English)

    徐子文; 黄正; 阮中健

    2003-01-01

    A new diffusion bonding technique combined with laser cladding process was developed to join TiAl alloy to itself and Ti-alloys. In order to enhance the weldability of TiAl alloys, Ti-alloy coatings were fabricated by laser cladding on the TiAl alloy. Ti powder and shaped Ti-alloy were respectively used as laser cladding materials. The materials characterization was carried out by OM, SEM, EDS and XRD analysis. The results show that the laser cladding process with shaped Ti-alloy remedy the problems present in the conventional process with powder, such as impurities, cracks and pores. The diffusion bonding of TiAl alloy with Ti-alloy coating to itself and Ti-alloy was carried out with a Gleeble 1500 thermal simulator. The sound bonds of TiAl/TiAl, TiAl/Ti were obtained at a lower temperature and with shorter time.

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

    Science.gov (United States)

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

    2015-05-29

    Functional shape memory alloys need to operate reversibly and repeatedly. Quantitative measures of reversibility include the relative volume change of the participating phases and compatibility matrices for twinning. But no similar argument is known for repeatability. This is especially crucial for many future applications, such as artificial heart valves or elastocaloric cooling, in which more than 10 million transformation cycles will be required. We report on the discovery of an ultralow-fatigue shape memory alloy film system based on TiNiCu that allows at least 10 million transformation cycles. We found that these films contain Ti2Cu precipitates embedded in the base alloy that serve as sentinels to ensure complete and reproducible transformation in the course of each memory cycle. Copyright © 2015, American Association for the Advancement of Science.

  13. Shape memory alloy flexures

    Energy Technology Data Exchange (ETDEWEB)

    Bellouard, Yves; Clavel, Reymond

    2003-07-25

    Flexures are used in precision engineering where highly accurate, wear-free, smooth and repeatable motion is desired. Flexures are based on deformation of material to achieve a motion between elastically joined parts. They are used in a variety of precision mechanisms such as high-resolution balances or high accuracy optical positioning stages. Shape memory alloys (SMA) are an attractive option in designing flexures. Superelastic flexures can withstand larger deformations for the same weight as a conventional flexure. In addition, the damping properties of SMA, controllable through the phase transformation, offer new design opportunities for adaptive compliant mechanisms. The martensitic phase transformation can also be used to shift the natural frequency of flexures adding useful functionalities such as vibration rejection. This paper presents design principles of SMA flexures based on non-linear beam theory. Results show a good agreement between measured and predicted data. In addition, experimental results on phase transformation effects on damping behavior are also presented. Both, natural-frequency shift and increased damping were observed in bulk-micro machined flexures using the R-phase transformation. These results demonstrate the feasibility of natural-frequency-tunable flexures.

  14. Zinc alloy enhances strength and creep resistance

    Energy Technology Data Exchange (ETDEWEB)

    Machler, M. [Fisher Gauge Ltd., Peterborough, Ontario (Canada). Fishercast Div.

    1996-10-01

    A family of high-performance ternary zinc-copper-aluminum alloys has been developed that provides higher strength, hardness, and creep resistance than the traditional zinc-aluminum alloys Zamak 3, Zamak 5, and ZA-8. Designated ACuZinc, mechanical properties comparable to those of more expensive materials make it suitable for high-load applications and those at elevated temperatures. This article describes the alloy`s composition, properties, and historical development.

  15. Thermomechanical behavior of comercial yellow gold alloy

    Directory of Open Access Journals (Sweden)

    Miloš G. Djordjević

    2016-03-01

    Full Text Available With the development of science and technology, in the late 19th century, began the research and application of new alloys for making jewelry. By adding different amounts of Cu and Ag alloy of Au, as well as adding some new elements (Zn, alloys were obtained with different color spectrum (from red to yellow and different technological and metallurgical characteristics. This paper aims to show thermomechanical behavior of commercial yellow Au alloys for making jewelry.

  16. Oxidation of low cobalt alloys

    Science.gov (United States)

    Barrett, C. A.

    1982-01-01

    Four high temperature alloys: U-700, Mar M-247, Waspaloy and PM/HIP U-700 were modified with various cobalt levels ranging from 0 percent to their nominal commercial levels. The alloys were then tested in cyclic oxidation in static air at temperatures ranging from 1000 to 1150 C at times from 500 to 100 1 hour cycles. Specific weight change with time and X-ray diffraction analyses of the oxidized samples were used to evaluate the alloys. The alloys tend to be either Al2O3/aluminate spinel or Cr2O3/chromite spinel formers depending on the Cr/Al ratio in the alloy. Waspaloy with a ratio of 15:1 is a strong Cr2O3 former while this U-700 with a ratio of 3.33:1 tends to form mostly Cr2O3 while Mar M-247 with a ratio of 1.53:1 is a strong Al2O3 former. The best cyclic oxidation resistance is associated with the Al2O3 formers. The cobalt levels appear to have little effect on the oxidation resistance of the Al2O3/aluminate spinel formers while any tendency to form Cr2O3 is accelerated with increased cobalt levels and leads to increased oxidation attack.

  17. Study of biofuels corrosiveness; Estudo da corrosividade de biocombustiveis

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Rafaela da Conceicao; Branco, Lucas da Paz Nogueira; Guimaraes, Maria Jose de Oliveria Cavalcanti; Seidl, Peter Rudolf [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica

    2012-07-01

    The replacement of crude oil derivatives with biofuels is part of an energy strategy, in which efficiency and conservation should play a leading role. The renewable nature of biodiesel is based in the fact that it is derived from raw materials from agricultural activities, instead of petroleum. Thinking about the increasingly production of biodiesel and its storage to make the proper mixtures, the corrosion of biodiesel tanks can occur over time. The copper corrosion test is used as the standard method for biodiesel corrosivity, however it is designed for diesel fuel from petroleum. Petrodiesel contains sulfur, which attacks the copper alloys. Since biodiesel is free of this element, it should be characterized in a different way. This work intends to analyze existing methodologies in order to evaluate the corrosivity of biodiesel. A literature search was performed in Web of Science database, selecting keywords for a comprehensive search. For the final analysis, a selection of papers classified according to publication year, country and main subject covered was used. Research on biofuels corrosivity is recent and major countries where published (USA, Malaysia and Brazil) which have advantages in terms of size and production of oil seeds. Biodiesel is more corrosive than petroleum diesel, but there is no sufficient evidences as to verify if the level of corrosion found in biodiesel is within acceptable limits for automotive components. Ferrous alloys are more resistant to biodiesel attack than non-ferrous alloys. Among non-ferrous alloys, copper and lead alloys are the most vulnerable, followed by aluminum. It is necessary to develop appropriate methodologies to determine and characterize the corrosivity of biodiesel on engine parts and alloys used in its manufacture and storage. (author)

  18. Improved thermal treatment of aluminum alloy 7075

    Science.gov (United States)

    Cocks, F. H.

    1968-01-01

    Newly developed tempering treatment considerably increases the corrosion resistance of 7075-T6 alloy and concomitantly preserves its yield strength. The results of tests on samples of the alloy subjected to the above treatments show that when the overaging period is 12 hours /at 325 degrees F/, the alloy exhibits a yield strength of 73,000 psi.

  19. Impact toughness of laser surface alloyed Aluminium

    CSIR Research Space (South Africa)

    Mabhali, Luyolo AB

    2012-03-01

    Full Text Available Laser surface alloying of aluminium AA1200 was performed with a 4kW Nd:YAG laser and the impact resistance of the alloys was investigated. The alloying powders were a mixture of Ni, Ti and SiC in different proportions. Surfaces reinforced...

  20. Corrosion Behaviour of New Zr Alloys

    DEFF Research Database (Denmark)

    Tolksdorf, E.

    1974-01-01

    Corrosion studies have indicated that the most promising replacements for Zicaloy-2 are ZrCrFe, ZrVFe and probably ZrNbTa, provided they are in their optimized condition. These alloys are conventionally manufactured alloys. An internally oxidized ZrMgO alloy is even superior, from the corrosion...

  1. Contribuição para o estudo da versão portuguesa da Positive and Negative Affect Schedule (PANAS): II – Estudo psicométrico

    OpenAIRE

    2005-01-01

    Estudo da adaptação da Positive and Negative Affect Schedule (PANAS; Watson, Clark & Tellegen, 1988) para a população portuguesa. A metodologia do estudo procurou replicar o estudo de desenvolvimento da escala original. Tal como o estudo original, pediu-se a 348 estudantes universitários que respondessem em que medida experienciaram as 60 emoções (traduzidas para Português) propostas por Zevon e Tellegen (1982) “durante os últimos dias” e “durante as últimas semanas”, numa escala de 5 pontos....

  2. Current research situation of titanium alloys in China

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Titanium and its alloys possess excellent comprehensive properties, and they are widely used in many fields. China pays great attentions to the research on new titanium alloys. This paper mainly reviews the research on new Ti alloys in China, for example, high strength and high toughness Ti alloys, burn resistant Tialloys, high temperature Ti alloys, low cost Ti alloys and so on.New basic theories on Ti alloys developed in China in recent years are also reviewed.

  3. PROCESS OF DISSOLVING ZIRCONIUM ALLOYS

    Science.gov (United States)

    Shor, R.S.; Vogler, S.

    1958-01-21

    A process is described for dissolving binary zirconium-uranium alloys where the uranium content is about 2%. In prior dissolution procedures for these alloys, an oxidizing agent was added to prevent the precipitation of uranium tetrafluoride. In the present method complete dissolution is accomplished without the use of the oxidizing agent by using only the stoichiometric amount or slight excess of HF required by the zirconium. The concentration of the acid may range from 2M to 10M and the dissolution is advatageously carried out at a temperature of 80 deg C.

  4. High strength, tough alloy steel

    Science.gov (United States)

    Thomas, Gareth; Rao, Bangaru V. N.

    1979-01-01

    A high strength, tough alloy steel is formed by heating the steel to a temperature in the austenite range (1000.degree.-1100.degree. C.) to form a homogeneous austenite phase and then cooling the steel to form a microstructure of uniformly dispersed dislocated martensite separated by continuous thin boundary films of stabilized retained austenite. The steel includes 0.2-0.35 weight % carbon, at least 1% and preferably 3-4.5% chromium, and at least one other substitutional alloying element, preferably manganese or nickel. The austenite film is stable to subsequent heat treatment as by tempering (below 300.degree. C.) and reforms to a stable film after austenite grain refinement.

  5. Alloy 718 for Oilfield Applications

    Science.gov (United States)

    deBarbadillo, John J.; Mannan, Sarwan K.

    2012-02-01

    Alloy 718 (UNS N07718) was developed for use in aircraft gas turbine engines, but its unique combination of room-temperature strength and aqueous corrosion resistance made it a candidate for oilfield fasteners, valves, drill tools, and completion equipment. As well environments became more severe, stress corrosion and hydrogen embrittlement failures in production equipment drove the evolution of the composition and microstructure that distinguish today's oilfield-grade 718 from aerospace grades. This paper reviews the development of the grade and its applications and describes some of its unique characteristics, testing, and manufacturing methods as well as newer alloys designed for high-pressure high-temperature (HPHT) conditions.

  6. Bulk nano-crystalline alloys

    OpenAIRE

    T.-S. Chin; Lin, C. Y.; Lee, M.C.; R.T. Huang; S. M. Huang

    2009-01-01

    Bulk metallic glasses (BMGs) Fe–B–Y–Nb–Cu, 2 mm in diameter, were successfully annealed to become bulk nano-crystalline alloys (BNCAs) with α-Fe crystallite 11–13 nm in size. A ‘crystallization-and-stop’ model was proposed to explain this behavior. Following this model, alloy-design criteria were elucidated and confirmed successful on another Fe-based BMG Fe–B–Si–Nb–Cu, 1 mm in diameter, with crystallite sizes 10–40 nm. It was concluded that BNCAs can be designed in general by the proposed cr...

  7. ZIRCONIUM-TITANIUM-BERYLLIUM BRAZING ALLOY

    Science.gov (United States)

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

    1962-06-12

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

  8. Alloy softening in binary iron solid solutions

    Science.gov (United States)

    Stephens, J. R.; Witzke, W. R.

    1976-01-01

    An investigation was conducted to determine softening and hardening behavior in 19 binary iron-alloy systems. Microhardness tests were conducted at four temperatures in the range 77 to 411 K. Alloy softening was exhibited by 17 of the 19 alloy systems. Alloy softening observed in 15 of the alloy systems was attributed to an intrinsic mechanism, believed to be lowering of the Peierls (lattice friction) stress. Softening and hardening rates could be correlated with the atomic radius ratio of solute to iron. Softening observed in two other systems was attributed to an extrinsic mechanism, believed to be associated with scavenging of interstitial impurities.

  9. Surface Tension Calculation of Undercooled Alloys

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

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

  10. An introduction to surface alloying of metals

    CERN Document Server

    Hosmani, Santosh S; Goyal, Rajendra Kumar

    2014-01-01

    An Introduction to Surface Alloying of Metals aims to serve as a primer to the basic aspects of surface alloying of metals. The book serves to elucidate fundamentals of surface modification and their engineering applications. The book starts with basics of surface alloying and goes on to cover key surface alloying methods, such as carburizing, nitriding, chromizing, duplex treatment, and the characterization of surface layers. The book will prove useful to students at both the undergraduate and graduate levels, as also to researchers and practitioners looking for a quick introduction to surface alloying.

  11. Estudos da formação de planetas terrestres

    OpenAIRE

    Costa, André Izidoro Ferreira da [UNESP

    2013-01-01

    O estudo da formação de planetas terrestres no Sistema Solar, é crucial para compre- endermos como outros sistemas planetários formam e também inferir as condições que poderiam ter influenciado a origem e evolução de vida na Terra. Esta Tese de douto- rado apresenta um estudo numérico da formação de planetas terrestres. Nosso objetivo principal é analisar o último estágio da formação desses planetas no Sistema Solar, em particular, a formação de Marte e a origem da água da Terra. Esses dois p...

  12. Microstructure and property characterization of a modified zinc-base alloy and comparison with bearing alloys

    Science.gov (United States)

    Prasad, B. K.; Patwardhan, A. K.; Yegneswaran, A. H.

    1998-02-01

    The microstructure and physical, mechanical, and tribological properties of a modified zinc-base alloy have been characterized. In order to assess its utility as a bearing alloy, its properties have also been compared with those of a similarly processed conventional zinc-base alloy and a leaded-tin bronze (conforming to ZA27 and SAE 660 specifications, respectively) used for bearing applications. The modified zinc-base alloy shows promise in terms of better elevated-temperature strength and wear response at higher sliding speeds relative to the conventional zinc-base alloy. Interestingly, the wear behavior (especially the seizure pressure) of the modified alloy was also comparable to that of the bronze specimens at the maximum sliding speed, and was superior at the minimum sliding speed. The modified alloy also attained lower density and better hardness. Alloy behavior has been linked to the nature and type of the alloy microconstituents.

  13. Ana Carolina Escosteguy: Cenários dos estudos culturais

    Directory of Open Access Journals (Sweden)

    Thaisa Cristina Bueno

    2016-01-01

    Full Text Available Autora do livro “Cartografia dos Estudos Culturais”, “Comunicação e recepção” (em coautoria com Nilda Jacks, “Leituras em comunicação, cultura e tecnologia”, além de coautora e organizadora em outras obras de referência sobre o tema cultura e comunicação no Brasil, Ana Carolina Escosteguy é hoje um dos nomes mais importantes quando se pensa em Estudos Culturais no país. Doutora em Ciências da Comunicação pela Universidade de São Paulo (2000, com pós-doutorado no CAMRI (Communication and Media Research Institute, associado ao Department of Journalism and Mass Communication da School of Media, Art and Design da University of Westminster (UK, Ana Carolina Escosteguy é professora titular da Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS e bolsista produtividade em pesquisa do CNPq, desde março 2001. Nesta entrevista ela discute pontos sensíveis da área, entre eles o pouco destaque das pesquisas desse campo têm tido no Jornalismo, o fato de a base teórica ser bem mais ampla que os tradicionais estudos de recepção a que são comumente aproximados, não se nega a tratar das confusões com a folkcomunicação, bem como as próprios limites e intersecções desse campo de estudos. Durante esta conversa, aproveita para apontar as obras que considera essenciais para adentrar na área e mostra coragem e segurança para se colocar como uma pesquisadora que busca entender o tempo atual, as tecnologias e as rupturas a partir da perspectiva do usuário. Confiram:

  14. Applications of shape memory alloys in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Asai, M.; Suzuki, Y. [Furukawa Electric Co., Ltd., Yokohama, Kanagawa (Japan). R and D Labs.

    2000-07-01

    In Japan, a first application of shape memory TiNi alloy was a moving flap in an air-conditioner which was developed as sensing function of shape memory alloy at Matsushista Electric Industrial Co. Then, shape memory utilized in a coffee maker, an electric rice-cooker, a thermal mixing valve and etc. were commercialized in Japan. And brassiere wires, a guide wire for medical treatment, an antenna for portable telephone and others were commercialized utilizing superelasticity. At the same time with these commercial products, there was not only progress in fabrication technology to effect accurate transformation temperature, but also the discovery of small hysteresis alloy such as R-phase or TiNiCu alloy and low transformation temperature alloy such as TiNiFe, TiNiV and TiNiCo alloys. Therefore the shape memory alloy market has expanded widely to electric appliances, automobile, residence, medical care and otherfield today. (orig.)

  15. High Damping Alloys and Their Application

    Institute of Scientific and Technical Information of China (English)

    Fuxing Yin

    2000-01-01

    Damping alloys show prospective applications in the elimination of unwanted vibrations and acoustic noise. The basic definitions and characterization methods of damping capacity are reviewed in this paper. Several physical mechanisms controlled by the alloy microstructure are responsible for the damping behavior in the damping alloys. Composite, dislocation, ferromagnetic and planar defect types are commonly classified for the alloys, which show the different damping behavior against temperature, frequency of vibration,amplitude of vibration and damping modes. Development of practically applicable damping alloys requires the higher mechanical properties and adequate workability, besides the high damping capacity. A new Mn-Cu damping alloy, named as M2052 alloy, is recently developed with possible industrial applications.

  16. Passive Corrosion Behavior of Alloy 22

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, R B; Payer, J H

    2006-01-10

    Alloy 22 (N06022) was designed to stand the most aggressive industrial applications, including both reducing and oxidizing acids. Even in the most aggressive environments, if the temperature is lower than 150 F (66 C) Alloy 22 would remain in the passive state having particularly low corrosion rates. In multi-ionic solutions that may simulate the behavior of concentrated ground water, even at near boiling temperatures, the corrosion rate of Alloy 22 is only a few nanometers per year because the alloy is in the complete passive state. The corrosion rate of passive Alloy 22 decreases as the time increases. Immersion corrosion testing also show that the newer generation of Ni-Cr-Mo alloys may offer a better corrosion resistance than Alloy 22 only in some highly aggressive conditions such as in hot acids.

  17. Paracrystalline property of high-entropy alloys

    Directory of Open Access Journals (Sweden)

    Shaoqing Wang

    2013-10-01

    Full Text Available Atomic structure models of six-component high-entropy alloys with body-centered cubic structure are successfully built according to the principle of maximum entropy for the first time. The lattice distortion parameters g of seven typical high-entropy alloys are calculated. From the optimized lattice configuration of high-entropy alloys, we show that these alloys are ideal three-dimensional paracrystals. The formation mechanism, structural feature, mechanical property, and application prospect of high-entropy alloys are discussed in comparison with the traditional alloys. The novel properties of body-centered cubic high-entropy alloys are attributed to the failure of dislocation deformation mechanism and the difficulty of directed particle diffusion.

  18. Passive Corrosion Behavior of Alloy 22

    Energy Technology Data Exchange (ETDEWEB)

    R.B. Rebak; J.H. Payer

    2006-01-20

    Alloy 22 (NO6022) was designed to stand the most aggressive industrial applications, including both reducing and oxidizing acids. Even in the most aggressive environments, if the temperature is lower than 150 F (66 C) Alloy 22 would remain in the passive state having particularly low corrosion rates. In multi-ionic solutions that may simulate the behavior of concentrated ground water, even at near boiling temperatures, the corrosion rate of Alloy 22 is only a few nano-meters per year because the alloy is in the complete passive state. The corrosion rate of passive Alloy 22 decreases as the time increases. Immersion corrosion testing also show that the newer generation of Ni-Cr-Mo alloys may offer a better corrosion resistance than Alloy 22 only in some highly aggressive conditions such as in hot acids.

  19. ABORDAGENS PARADIGMÁTICAS ALTERNATIVAS: POSSIBILIDADES PARA ESTUDOS EM ADI

    Directory of Open Access Journals (Sweden)

    Christine da Silva Schröeder

    2012-12-01

    Full Text Available Nossa proposta é incentivar a apropriação de abordagens paradigmáticas alternativas para a pesquisa na área de Administração da Informação (ADI, a partir de perspectivas que se contrapõem à ontologia positivista-funcionalista – ou, de outro lado, podem complementá-la, oportunizando a realização de estudos reflexivos, não necessariamente performativos, e “desnaturalizados”. Adotamos os conceitos de reflexividade, não-performatividade e desnaturalização a partir de seu uso por Fournier e Grey (2007, ao referirem-se aos estudos críticos em Administração (ou Critical Management Studies - CMS. Atestamos que os três conceitos nos são valiosos porque nos auxiliam a definir condições pelas quais entendemos que se manifesta pensamento crítico – e, por assim dizer, inspiram a pesquisa multi e interparadigmática. Através das possibilidades deste tipo de pesquisa, podemos lançar olhares potencialmente ampliados sobre a teoria e a prática em Administração da Informação, que trazem implicações não apenas epistemológicas, mas, sobretudo, metodológicas para os estudos da área.

  20. Marketing do mercado de luxo: Estudo de caso Victoria's Secret

    Directory of Open Access Journals (Sweden)

    Ana Francisca Giuliani

    2013-12-01

    Full Text Available Este artigo teve por objetivo identificar quais são as estratégias de marketing utilizadas pela empresa varejista Victoria’s Secret para a fidelização do consumidor de luxo em nível global. O estudo caracterizou-se como uma pesquisa qualitativa, utilizando-se como estratégia de campo o estudo de caso de caráter ilustrativo. Para o alcance do objetivo proposto, dividiu-se o estudo em duas fases. Na primeira, denominada exploratória, buscou-se em dados secundários o embasamento para a construção do referencial teórico. Na segunda, adotou-se a técnica de pesquisa por observação, utilizando-se os sites da Victoria’s Secret, e analisou-se o composto de marketing aplicado ao mercado de luxo com base no modelo proposto por Nahás (2009. Concluiu-se que as estratégias da referida empresa se baseiam no luxo acessível, de modo que, além de conquistar o consumidor, a Victoria’s Secret consegue manter sua fidelidade por apresentar estratégias de forte apelo emocional.

  1. A sociologia funcionalista nos estudos organizacionais: foco em Durkheim

    Directory of Open Access Journals (Sweden)

    Augusto Cabral

    Full Text Available O tema que estrutura este ensaio é o da sociologia funcionalista, particularmente em termos de sua influência nos estudos organizacionais. O seu foco de análise é duplo. Em um primeiro momento, as obras de Durkheim. Em um segundo momento, o impacto e a supremacia dos enfoques funcionalistas nos estudos organizacionais. Embora seus segmentos estejam inter-relacionados, ele é composto de quatro partes. Na primeira, é feita uma análise histórica da emergência e sistematização das ciências sociais, de modo a traçar sua evolução até o surgimento dos trabalhos de Durkheim. Na segunda, tomando como referencial a obra de Burrell e Morgan (1979, é estudado o paradigma funcionalista em termos de sua origem e expoentes, com destaque para Comte e Spencer, visando chegar a uma compreensão inicial do pensamento de Durkheim e de sua sociologia. Na terceira, a vida e as principais obras de Durkheim são sumariadas e discutidas. Por fim, o status atual dos estudos organizacionais -vistos como um conjunto impreciso, elástico e eclético de teorias e pesquisas sociais voltados para os problemas das organizações -é analisado em termos de seus pressupostos epistemológicos e ontológicos subjacentes, como meio de explicitar a supremacia dos enfoques positivistas-funcionalistas.

  2. O caso do psicodiagnóstico: um estudo institucional

    Directory of Open Access Journals (Sweden)

    Marlene Guirado

    2005-01-01

    Full Text Available O psicodiagnóstico é uma prática recorrente de estudo de caso em Psicologia, independentemente de ser feito em consultórios particulares, escolas, hospitais, ambulatórios e/ou instituições para-educativas. O presente artigo discute a dimensão institucional desse atendimento na medida em que se trata de um dispositivo que, cada vez mais, legitima seu objeto: o conhecimento do psiquismo de quem se expõe aos serviços do psicólogo. Tal discussão parte do destaque de conceitos como discurso, sujeito, instituição e análise, tomados nos terrenos da Psicanálise e da análise de instituições concretas, para configurar uma possibilidade de estudo de caso que considere o contexto institucional do (ou, em que se fez o diagnóstico. Por fim, faz-se uma proposta de como proceder a um estudo de caso que suponha a força constitutiva desse contexto sobre o resultado do psicodiagnóstico de um cliente/paciente do psicólogo.

  3. Recrutamento de participantes no Estudo Longitudinal de Saude do Adulto

    Directory of Open Access Journals (Sweden)

    Estela M L Aquino

    2013-06-01

    Full Text Available OBJETIVO: Apresentar as estratégias de comunicação e recrutamento no Estudo Longitudinal de Saúde do Adulto (ELSA-Brasil e discutir os resultados alcançados na constituição da coorte. MÉTODOS: As estratégias foram voltadas à divulgação, à institucionalização e ao recrutamento propriamente dito. As ações de comunicação pretenderam promover o fortalecimento de imagem institucional positiva para o estudo, a gestão de conhecimentos e o diálogo eficaz com seu público-alvo. Foi criado web site oficial visando dialogar com diferentes públicos, funcionar como difusor científico e contribuir para a consolidação da imagem do estudo perante a sociedade. RESULTADOS: Foram recrutados 16.435 mulheres e homens, servidores ativos e aposentados de seis instituições públicas de ensino e pesquisa para constituir a coorte de 15.105 participantes. As metas de recrutamento foram plenamente alcançadas nos seis centros, com leve predomínio de mulheres e daqueles mais jovens, e um pouco menos de servidores com menor escolarização. CONCLUSÕES: As estratégias utilizadas se mostraram adequadas e essenciais para o sucesso da captação e participação dos servidores.

  4. ESTRATÉGIAS DE MARKETING: UM ESTUDO PRÁTICO

    Directory of Open Access Journals (Sweden)

    André Francisco Alcântara Fagundes

    2008-06-01

    Full Text Available Este trabalho objetivou o estudo da gestão da Cooperativa de Economia e Crédito Mútuo dos Profissionais da Saúde de Viçosa e Região (Unicred Viçosa, como forma de gerar uma melhoria nos negócios e assim ampliar o quadro social da cooperativa. Utilizou-se como metodologia a pesquisa descritiva e qualitativa por meio de estudo de caso. Os métodos de pesquisa utilizados foram a abordagem participativa e o questionário dirigido aos 430 cooperados da Unicred Viçosa – tamanho de amostra finita. O referencial teórico abordou bibliografia de marketing e estratégia, destacando a análise da matriz SWOT, a qual foi eleita como a mais adequada ferramenta de gestão para o caso da cooperativa. Concluiu-se com o estudo que a cooperativa Unicred Viçosa teria que estabelecer critérios mais eficazes para a comunicação de seus objetivos e metas aos cooperados, e que a matriz SWOT se mostrou eficiente no que tange ao suporte à tomada de decisão.

  5. Nickel, cobalt, and their alloys

    CERN Document Server

    2000-01-01

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

  6. Hydrostatic extrusion of magnesium alloys

    NARCIS (Netherlands)

    Sillekens, W.H.; Bohlen, J.

    2012-01-01

    This chapter deals with the capabilities and limitations of the hydrostatic extrusion process for the manufacturing of magnesium alloy sections. Firstly, the process basics for the hydrostatic extrusion of materials in general and of magnesium in particular are introduced. Next, some recent research

  7. Gold color in dental alloys.

    Science.gov (United States)

    Cameron, T

    1997-01-01

    This article will help the dental laboratory with alloy selection by exploring how the relationship among color, ductility and strength applies to gold and how color can be quantified. Because higher quality materials translate into higher profits, upselling to the dentist and patient is also discussed.

  8. Ultrasonic processing of aluminum alloys

    NARCIS (Netherlands)

    Zhang, L.

    2013-01-01

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

  9. Superb nanocrystalline alloys for plating

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ With high rigidity and antiwear performance,nanocrystalline metals and their alloys can find wide applications in surface protection.However, the existence of grain boundaries often leads to erosive micro-batteries which accelerate the process of corrosion.Therefore, it has already become a key issue for surface engineering researchers to find nano materials with higher lubricating, anticorrosion and antiwear capacities.

  10. Microstructure and thermal stability of mechanically alloyed Al3Ti/Al alloy

    Institute of Scientific and Technical Information of China (English)

    林建国; 魏浩岩; 黄正

    2001-01-01

    The microstructure stability of Al3Ti/Al alloy prepared by mechanical alloying (MA) was investigated in the simulating environment in which they may be used. The results show that the MA alloy possesses fine microstructure (the grain size is about 0.5  μm). After cycling loaded followed by heat exposure at 350  ℃ for 24  h, no microstructure coarsening of the alloy occurred, which means that the Al3Ti/Al alloy behaves good microstructure stability at high temperature. The compression yield strength of the alloy reaches up to 247  MPa at 350  ℃.

  11. Method of producing superplastic alloys and superplastic alloys produced by the method

    Science.gov (United States)

    Troeger, Lillianne P. (Inventor); Starke, Jr., Edgar A. (Inventor); Crooks, Roy (Inventor)

    2002-01-01

    A method for producing new superplastic alloys by inducing in an alloy the formation of precipitates having a sufficient size and homogeneous distribution that a sufficiently refined grain structure to produce superplasticity is obtained after subsequent PSN processing. An age-hardenable alloy having at least one dispersoid phase is selected for processing. The alloy is solution heat-treated and cooled to form a supersaturated solid solution. The alloy is plastically deformed sufficiently to form a high-energy defect structure useful for the subsequent heterogeneous nucleation of precipitates. The alloy is then aged, preferably by a multi-stage low and high temperature process, and precipitates are formed at the defect sites. The alloy then is subjected to a PSN process comprising plastically deforming the alloy to provide sufficient strain energy in the alloy to ensure recrystallization, and statically recrystallizing the alloy. A grain structure exhibiting new, fine, equiaxed and uniform grains is produced in the alloy. An exemplary 6xxx alloy of the type capable of being produced by the present invention, and which is useful for aerospace, automotive and other applications, is disclosed and claimed. The process is also suitable for processing any age-hardenable aluminum or other alloy.

  12. PERSPECTIVES OF MOLIBDENUM CONTAINING MATERIALS APPLICATION FOR ALLOYING OF IRONCARBON ALLOYS DURING MANUFACTURING OF CRITICAL CASTINGS

    Directory of Open Access Journals (Sweden)

    A. G. Slutsky

    2015-01-01

    Full Text Available Motor is one of most important part of automobile determine its economical effectiveness of usage. On the other hand, sleeves, pistons and rings are crucible parts as they determine the service life of a motor. These parts are producing in big scale – dozens of millions pieces. Increase of cylinder sleeves physical-mechanical properties results in prolongation of motor service life and improvement of motor’s characteristics. Nowadays low alloyed cast irons with perlite structure are used to manufacture motor’s sleeves. For alloying purposes such traditional elements as Cr, Ni, Cu, and V are applied. But it is interesting to use molybdenum for cast iron alloying. It is known that alloying of alloys allows considerable increasing of consumption properties of castings. But in spite of advantages of alloys alloying the increase of molybdenum containing iron-carbon alloys production is restricted by economical reasons – high cost of alloying additions. Expenditures on alloying additions can be reduced by the application cheap secondary alloys in the charge. So, the present paper is devoted to investigation of alloying peculiarities during the treatment of ferrous alloys with molybdenum applying different initial materials.

  13. Hydrogen ingress into copper-nickel alloys

    Energy Technology Data Exchange (ETDEWEB)

    Pound, B.G. (SRI International, Menlo Park, CA (United States). Materials Research Center)

    1994-04-01

    Hydrogen (H) ingress into two copper (Cu)-nickel (Ni) alloys -- a commercial 77% Cu-15% Ni alloy (aged) and alloy K-500 (UNS N05500, aged and unaged) --- was studied using a technique referred to as hydrogen ingress analysis by potentiostatic pulsing (HIAPP). Anodic current transients obtained for these alloys in an acetate buffer (1 mol/L acetic acid + 1 mol/L sodium acetate [NaAc]) were analyzed using a diffusion-trapping model to determine trapping constants and H entry fluxes. A small increase was observed in the irreversible trapping constant for alloy K-500 with aging. Trapping constants of the aged alloys were similar within the limits of uncertainty, but H entry flux for the 77% Cu alloy was lower than that for aged or unaged alloy K-500. The lower flux may have accounted at least partly, for the Cu alloy's higher resistance to H embrittlement. Trap densities were consistent qualitatively with levels of sulfur (S) and phosphorus (P) in the two alloys. This finding supported an assumption that S and P provided the primary irreversible traps.

  14. Alloy substantially free of dendrites and method of forming the same

    Science.gov (United States)

    de Figueredo, Anacleto M.; Apelian, Diran; Findon, Matt M.; Saddock, Nicholas

    2009-04-07

    Described herein are alloys substantially free of dendrites. A method includes forming an alloy substantially free of dendrites. A superheated alloy is cooled to form a nucleated alloy. The temperature of the nucleated alloy is controlled to prevent the nuclei from melting. The nucleated alloy is mixed to distribute the nuclei throughout the alloy. The nucleated alloy is cooled with nuclei distributed throughout.

  15. An electrochemical investigation of mechanical alloying of MgNi-based hydrogen storage alloys

    Science.gov (United States)

    Jiang, Jian-Jun; Gasik, Michael

    The electrochemical properties of amorphous MgNi-based hydrogen storage alloys synthesized by mechanical alloying (MA) were evaluated. The results show that these amorphous Mg 50Ni 50 alloys exhibit a higher discharge capacity and relatively good rate capacity at a suitable grinding time while their cycle life is very poor. In order to improve the cycle life, the surface of the amorphous Mg 50Ni 50 alloy was coated with Ti, Al and Zr in Spex 8000 mill/mixer and the coating effects were further investigated. Based on experimental results, two kinds of MgNi-based amorphous alloys are designed by substituting part of Mg in MgNi-based alloys by suitable elements. These alloys are then composed of four components. Thus, the cycle life of electrodes consisting of these quaternary amorphous alloys is greatly improved.

  16. Grain refinement of AZ31 magnesium alloy by Al-Ti-C-Y master alloy

    Institute of Scientific and Technical Information of China (English)

    XU Chunxiang; LU Binfeng; L(U) Zhengling; LIANG Wei

    2008-01-01

    Al-Ti-C-Y master alloy was prepared by combining SHS technique and melting-casting method. The microstructure of master alloy and its grain-refining effect on AZ31 alloy were investigated by means of OM, XRD, SEM and EDS. Experimental results indicated that the prepared master alloy consisted of α-Al, TiAl3, TiC and Al3Y phases, and exhibited good grain-refining performance of AZ31 alloy. Morphology of α-Mg changed from coarse dendritic to fine equiaxed and the average grain size of α-Mg matrix reduced from the original 580 to 170 μm after adding 1.0 wt.% master alloy. The grain refining efficiency of Al-Ti-C-Y master alloy on AZ31 alloy was mainly attributed to heterogeneous nucleation of TiC particles and grain growth restriction of Al-Y compound or TiC at grain boundaries.

  17. Micro-Structures of Hard Coatings Deposited on Titanium Alloys by Laser Alloying Technique

    Science.gov (United States)

    Li, Wei; Yu, Huijun; Chen, Chuanzhong; Wang, Diangang; Weng, Fei

    2013-01-01

    This work is based on micro-structural performance of the Ti-B4C-C laser alloying coatings on Ti-6Al-4V titanium alloy. The test results indicated that laser alloying of the Ti-B4C-C pre-placed powders on the Ti-6Al-4V alloy substrate can form the ceramics reinforced hard alloying coatings, which increased the micro-hardness and wear resistance of substrate. The test result also indicated that the TiB phase was produced in alloying coating, which corresponded to its (101) crystal plane. In addition, yttria has a refining effect on micro-structures of the laser alloying coating, and its refinement mechanism was analyzed. This research provided essential experimental and theoretical basis to promote the applications of the laser alloying technique in manufacturing and repairing of the aerospace parts.

  18. Status of Testing and Characterization of CMS Alloy 617 and Alloy 230

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Weiju [ORNL; Santella, Michael L [ORNL; Battiste, Rick [ORNL; Terry, Totemeier [Idaho National Laboratory (INL); Denis, Clark [Idaho National Laboratory (INL)

    2006-08-01

    Status and progress in testing and characterizing CMS Alloy 617 and Alloy 230 tasks in FY06 at ORNL and INL are described. ORNL research has focused on CMS Alloy 617 development and creep and tensile properties of both alloys. In addition to refurbishing facilities to conduct tests, a significant amount of creep and tensile data on Alloy 230, worth several years of research funds and time, has been located and collected from private enterprise. INL research has focused on the creep-fatigue behavior of standard chemistry Alloy 617 base metal and fusion weldments. Creep-fatigue tests have been performed in air, vacuum, and purified Ar environments at 800 and 1000 C. Initial characterization and high-temperature joining work has also been performed on Alloy 230 and CCA Alloy 617 in preparation for creep-fatigue testing.

  19. New Dental Alloys with Special Consumer Properties

    Institute of Scientific and Technical Information of China (English)

    TYKOCHINSKIY D. S.; VASEKIN V. V.

    2012-01-01

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

  20. First principles theory of disordered alloys and alloy phase stability

    Energy Technology Data Exchange (ETDEWEB)

    Stocks, G.M.; Nicholson, D.M.C.; Shelton, W.A. [and others

    1993-06-05

    These lecture notes review the LDA-KKR-CPA method for treating the electronic structure and energetics of random alloys and the MF-CF and GPM theories of ordering and phase stability built on the LDA- KKR-CPA description of the disordered phase. Section 2 lays out the basic LDA-KKR-CPA theory of random alloys and some applications. Section 3 reviews the progress made in understanding specific ordering phenomena in binary solid solutions base on the MF-CF and GPM theories of ordering and phase stability. Examples are Fermi surface nesting, band filling, off diagonal randomness, charge transfer, size difference or local strain fluctuations, magnetic effects; in each case, an attempt is made to link the ordering and the underlying electronic structure of the disordered phase. Section 4 reviews calculations of electronic structure of {beta}-phase Ni{sub c}Al{sub 1-c} alloys using a version of the LDA-KKR-CPA codes generalized to complex lattices.

  1. TENDÊNCIAS DOS ESTUDOS COM PLANTAS MEDICINAIS NO BRASIL

    Directory of Open Access Journals (Sweden)

    Fernanda Melo Carneiro

    2014-12-01

    Full Text Available As plantas medicinais são utilizadas pelo homem desde o início da história e atualmente empregadas como recursos na medicina alternativa por grande parte da população mundial. Esse uso deve-se à facilidade de acesso às plantas em relação aos medicamentos alopáticos. O objetivo deste trabalho foi, primariamente, desenvolver uma análise cienciométrica sobre as tendências dos estudos com plantas medicinais no Brasil, investigando se o número de trabalhos cresceu ao longo dos anos. Além disso, foi identificamos as principais plantas que são estudadas pelo seu principio medicinal no Brasil. Para a pesquisa foi empregada a base de dados Scielo, com artigos de 1995 a 2011, utilizando a palavra “Planta Medicinal” como palavra-chave. Foram avaliados 329 artigos, mas somente 265 foram compatíveis à pesquisa. Artigos que não foram desenvolvidos no Brasil; que não utilizaram o termo planta medicinal; ou não citaram plantas foram excluídos das análises. Em cada artigo selecionado foram coletadas as seguintes informações: título do artigo, quantidade de autores, instituições responsáveis pelo estudo, local das instituições, ano de publicação, tipo de estudo (ex.: farmacológico, agropecuário e ecológico e as plantas que foram estudadas. Por meio de análises desses dados foi possível verificar as tendências dos estudos com plantas medicinais no Brasil. Conforme esperado, a maior parte dos artigos avaliados estão voltados para a Farmacologia, com aplicação em diversas áreas da saúde e em segundo lugar a Agropecuária, devido ao interesse em desenvolver produtos a partir de plantas para o controle de pragas. Entretanto, verificou-se o emprego em outras áreas, como a Bioquímica, Botânica, Ecologia, Genética/Molecular e Educação que apesar de serem menos frequentes, são essenciais, pois os estudos com plantas medicinais requerem profissionais de múltiplas áreas. Além da investigação da medicina popular

  2. Effects of segregation of primary alloying elements on the creep response in magnesium alloys

    DEFF Research Database (Denmark)

    Huang, Y.D.; Dieringa, H.; Hort, N.

    2008-01-01

    The segregation of primary alloying elements deteriorates the high temperature creep resistance of magnesium alloys. Annealing at high temperatures alleviating their segregations can improve the creep resistance. Present investigation on the effect of segregation of primary alloying elements...... on the creep response may provide some useful information about how to improve the creep resistance of magnesium alloys in the future. (c) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved....

  3. The Influence of Novel Alloying Additions on the Performance of Magnesium Alloy AZ31B

    Science.gov (United States)

    2013-11-01

    alloys are based on a rather small group of alloying elements, there are often limited differences between them in properties (strength, corrosion ...Research Laboratory (ARL). Initially, the discussions focused on ways to improve the corrosion resistance of magnesium ( Mg ) alloys to increase the...elements display little tendency to alter precipitates or otherwise adversely influence the corrosion performance of the base alloy . Based on these

  4. Theory of Random Anisotropic Magnetic Alloys

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker

    1976-01-01

    A mean-field-crystal-field theory is developed for random, multicomponent, anisotropic magnetic alloys. It is specially applicable to rare-earth alloys. A discussion is given of multicritical points and phase transitions between various states characterized by order parameters with different...... spatial directions or different ordering wave vectors. Theoretical predictions based on known parameters for the phase diagrams and magnetic moments for the binary rare-earth alloys of Tb, Dy, Ho, and Er, Tb-Tm, Nd-Pr, and pure double-hcp Nd agree qualitatively with the experimental observations....... Quantitative agreement can be obtained by increasing the interaction between different alloy elements, in particular for alloys with very different axial anisotropy, e.g., Tb-Tm. A model system consisting of a singlet-singlet and singlet-doublet alloy is discussed in detail. A simple procedure to include...

  5. Magnetic Characteristics of Two Metglas Alloys

    Science.gov (United States)

    Blatnik, Marie; SNS nEDM Collaboration

    2016-09-01

    Magnetic shielding is gaining greater significance as precision experiments become more sensitive, such as for the Spallation Neutron Source nEDM [neutron electric dipole moment] measurement. Targeting a sensitivity of 10-28 e-cm, the SNS nEDM collaboration minimizes magnetic shield gradients and magnetic noise with a superconducting lead shield and several shield layers that include using a Metglas layer as a primary component. Metglas is a thin ribbon of proprietary engineered alloy that comes in many varieties. One alloy with high (as cast) permeability is Metglas alloy 2705M, which is primarily composed of Cobalt. However, this alloy will activate under neutron radiation and is therefore unsuitable. However, another high-performance Metglas alloy, 2826 MB, contains only trace amounts of Cobalt. A study of the shielding characteristics of the two alloys was performed, paying close attention to field oscillation frequency and magnitude.

  6. Bulk amorphous Mg-based alloys

    DEFF Research Database (Denmark)

    Pryds, Nini

    2004-01-01

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

  7. Bonding theory for metals and alloys

    CERN Document Server

    Wang, Frederick E

    2005-01-01

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

  8. A lightweight shape-memory magnesium alloy.

    Science.gov (United States)

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

    2016-07-22

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

  9. Wetting behavior of alternative solder alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hosking, F.M.; Vianco, P.T.; Hernandez, C.L.; Rejent, J.A.

    1993-07-01

    Recent economic and environmental issues have stimulated interest in solder alloys other than the traditional Sn-Pb eutectic or near eutectic composition. Preliminary evaluations suggest that several of these alloys approach the baseline properties (wetting, mechanical, thermal, and electrical) of the Sn-Pb solders. Final alloy acceptance will require major revisions to existing industrial and military soldering specifications. Bulk alloy and solder joint properties are consequently being investigated to validate their producibility and reliability. The work reported in this paper examines the wetting behavior of several of the more promising commercial alloys on copper substrates. Solder wettability was determined by the meniscometer and wetting balance techniques. The wetting results suggest that several of the alternative solders would satisfy pretinning and surface mount soldering applications. Their use on plated through hole technology might be more difficult since the alloys generally did not spread or flow as well as the 60Sn-40Pb solder.

  10. Recrystallization of Al-Sc alloys

    Energy Technology Data Exchange (ETDEWEB)

    Drits, M.E.; Toropova, L.S.; Bykov, Yu.G.; Ber, L.B.

    Scandium effect on the temperature range of aluminium recrystallization was investigated. Al-Sc alloys were studied under cold rolled and hot pressed conditions. It is found that the temperature range of Al-Sc alloy recrystallization depends on ScAl/sub 3/ particle dispersion during recrystallization heats. During heating in quenched alloys at 200-300 deg C decomposition occurs which prevents recrystallization, In the alloys with scandium contents less 0.2% decomposition and recrystallization processes pass simultaneously. In quenched alloys with scandium contents over 0.2% and in aged alloys the initiation and subsequent development of recrystallization are determined by the processes of coalescence and solution of ScAl/sub 3/ phase particles.

  11. Biocorrosion study of titanium-nickel alloys.

    Science.gov (United States)

    Chern Lin, J H; Lo, S J; Ju, C P

    1996-02-01

    The present study provides results of the corrosion behaviour in Hank's physiological solution and some other properties of three Ti-Ni alloys with 18, 25 and 28.4 wt% Ni, respectively. Results indicate that alpha-titanium and Ti2Ni were the two major phases in all three Ti-Ni alloys. The relative amount of the Ti2Ni phase increased with additional Ni content. Hardness of the Ti-Ni alloys also increased with added nickel content, ranging from 310 to 390 VHN, similar to the hardness of enamel. Melting temperatures of the Ti-Ni alloys were all lower than that of pure titanium by least 600 degrees C. The three Ti-Ni alloys behaved almost identically when potentiodynamically polarized in Hank's solution at 37 degrees C. The critical anodic current densities of the alloys were nearly 30 microA/cm2 and the breakdown potentials were all above 1100 mV (SCE).

  12. Contribuições da fenomenologia para os estudos organizacionais

    Directory of Open Access Journals (Sweden)

    Diego Luiz Teixeira Boava

    Full Text Available Este artigo discute elementos que viabilizam outra possibilidade de compreensão dos fenômenos administrativos, através de uma descrição propedêutica da fenomenologia e do método fenomenológico. Objetiva-se, assim, apresentar as principais contribuições e possibilidades da fenomenologia para os estudos organizacionais. Aprofunda-se em considerações sobre a fenomenologia em geral e os diversos tipos de métodos fenomenológicos em particular, buscando esclarecer sobre a filosofia existente nesses temas, para auxiliar os pesquisadores em seu labor diário. Discorre-se também sobre a redução, que na verdade são duas: a eidética e a fenomenológica. Tais reduções são vitais para retirar o homem de sua atitude natural. Outro assunto aqui abordado é a transposição do método fenomenológico do campo filosófico para o campo da pesquisa empírica. Diante dessa contextualização, tem-se o último assunto a ser abordado, que vai diretamente ao encontro do objetivo desta pesquisa, discutindo-se a utilização da fenomenologia no contexto da administração. A título de ilustração, são apresentados diversos estudos que têm a fenomenologia como tema, bem como um método fenomenológico empírico específico da área de estudos organizacionais. Dessa maneira, a temática neste artigo é situada, sendo preciso agora avançar em direção a outras possibilidades.

  13. Redes e Responsabilidade Social Corporativa: Um Estudo de Caso

    Directory of Open Access Journals (Sweden)

    Adriana Teixeira Bastos

    2015-01-01

    Full Text Available  O presente estudo visa a contribuir para a elucidação de questões relacionadas aos temas responsabilidade social corporativa (RSC e redes de cooperação entre empresas. Com este intento busca-se, através de um estudo de caso, compreender quais os impactos das redes sobre as estratégias de RSC. O estudo de caso em questão está baseado nas ações de Desenvolvimento Regional Sustentável (DRS de uma instituição financeira, que considera esta prática como uma forma dela e de parceiros realizarem suas ações de RSC. O artigo está estruturado considerando-se inicialmente a introdução, a discussão teórica sobre os dois temas que se pretende relacionar (redes e RSC e, após a elucidação sobre a metodologia do trabalho, é apresentada a metodologia do programa DRS da instituição financiadora (Banco Digama e a descrição da aplicação prática do programa para um grupo de parceiros da rede. Dando continuidade, são apresentadas as análises e discussões e, por último, as considerações finais. Entre os principais itens da conclusão, observa-se que os objetivos das organizações, relacionados às RSC, podem ser diferentes entre si, assim como os resultados obtidos, permitindo, inclusive, a coexistência na rede de atores que não alcançaram, na totalidade, seus principais objetivos, embora realizem atividades relacionadas à responsabilidade social. 

  14. Jovem aprisionado em regime semi-aberto: um estudo transdisciplinar

    OpenAIRE

    Lazzaron, Leandra Regina

    2008-01-01

    A presente dissertação, vinculada à linha de pesquisa “Criminologia e Controle Social”, do Programa de Pós-Graduação em Ciências Criminais, da Faculdade de Direito da Pontifícia Universidade Católica do Rio Grande do Sul, identifica o perfil do jovem apenado, aprisionado em regime semi-aberto, no Instituto Penal de Viamão, com base na escala PCL-R. O estudo de campo foi realizado na instituição prisional e avaliou 40 jovens, com idade de 18 a 23 anos, que cumprem pena em regime semi-aberto. O...

  15. Craniostenose em gêmeos: estudo genético

    Directory of Open Access Journals (Sweden)

    Walter Carlos Pereira

    1968-09-01

    Full Text Available É relatada a ocorrência de formas clínicas diversas de craniostenose em gêmeos de sexo diferente. A menina apresentava obliteração completa da sutura coronaria e dos dois terços anteriores da sutura sagital; no menino a sutura sagital era a única afetada. O estudo genético mostrou que a craniostenose independe de aberrações cromossômicas, indicando ser transmitida por gens recessivos raros de natureza autossômica.

  16. Estudo teórico de formas condensadas de polianilinas

    OpenAIRE

    Liliana Yolanda Ancalla Dávila

    2005-01-01

    Neste trabalho estudamos o efeito de empacotamento, em diferentes formas condensadas, sobre as propriedades estruturais e eletrônicas de um polímero orgânico conjugado, a polianilina, através de simulações teóricas. A metodologia teórica empregada depende do número de átomos nos sistemas escolhidos, e das propriedades investigadas. Assim, para os filmes com milhares de átomos, utilizamos métodos clássicos para a obtenção das propriedades estruturais. Já para o estudo das propriedades eletrôni...

  17. A entrevista motivacional com alcoolistas: um estudo longitudinal

    OpenAIRE

    Oliveira,Margareth da Silva; Andretta,Ilana; Rigoni, Maisa dos Santos; Szupszynski, Karen Priscila Del Rio

    2008-01-01

    Este foi um estudo de seguimento com pacientes alcoolistas que participaram de um ensaio clínico em que foi empregada Entrevista Motivacional. A amostra constituiu-se de 152 sujeitos alocados randomicamente em dois grupos: grupo de intervenção submetido à Entrevista Motivacional (GI), e um grupo controle submetido a tratamento padrão (GC). Os instrumentos utilizados foram: entrevista estruturada e o FORM-90. Na avaliação inicial (T1), realizada entre os anos de 1999 e 2001, foram avaliados 15...

  18. Encefalopatia hepática: estudo de 50 casos

    Directory of Open Access Journals (Sweden)

    Luiz Antonio de Lima Resende

    1984-12-01

    Full Text Available Os autores apresentam estudo retrospectivo de 50 pacientes com encefalopatia hepática atendidos no Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto a partir de 1959 e discutem os aspectos clínicos, laboratoriais e anátomo-patológicos. Expõem os diagnósticos das hepatopatias, os fatores precipitantes dos episódios de coma e pré-coma hepático e enfatizam o papel da gasometria arterial no estabelecimento do diagnóstico.

  19. Anorexia nervosa e família : estudo de caso

    OpenAIRE

    Simone Marques Borges

    2009-01-01

    Os transtornos alimentares têm despertado interesse entre os profissionais de saúde em decorrência do crescente aumento de casos, alguns deles veiculados na mídia. Apesar disso, muitas dúvidas ainda cercam essas patologias. O funcionamento do sistema familiar de adolescentes com diagnóstico de anorexia nervosa tem sido tema de investigação por autores da terapia familiar sistêmica e os estudos têm relacionado o transtorno a algumas características da dinâmica conjugal e familiar. Esta pesquis...

  20. O efeito do stresse no julgamento moral: um estudo experimental

    OpenAIRE

    Carvalhinho, Helena Paula Polido

    2015-01-01

    Dissertação de Mestrado, Psicologia Clínica e da Saúde, Faculdade de Ciências Humanas e Sociais, Universidade do Algarve, 2015 Alguns estudos recentes sugerem que as emoções têm um impacto significativo no julgamento moral e, em certa medida, a variação de estados emocionais induzida por situações de stresse também parece condicionar a resposta moral. Neste sentido, alguns autores sugerem que sujeitos sob impacto de stresse realizam julgamentos morais menos calculistas, mais emocionais. Co...

  1. "Buzz marketing" : estudo de caso da marca Red Bull

    OpenAIRE

    Conceição, Miguel David

    2012-01-01

    Este relatório é baseado no estágio efetuado na agência de publicidade Ogilvy & Mather e é dedicado à temática do Buzz Marketing. De modo a poder explorar a fundo as dinâmicas deste tema foi feita uma análise à estratégia de marketing da marca Red Bull, considerada como um dos principais estudos de caso no âmbito do Buzz Marketing. Este tema pode ser definido como uma estratégia de marketing inovadora cujo objetivo principal é a criação de conversas entre os consumidores, colocando-os a falar...

  2. Miopatia miotubular: estudo clinico, eletrofisiologico e histologico de um caso

    Directory of Open Access Journals (Sweden)

    José L. Alonso

    1981-12-01

    Full Text Available São apresentados os resultados dos exames clínicos, eletrofisiológicos e do estudo do ponto motor, da imunofluorescência, da histoquímica e da ultrami-croscopia da biópsia muscular de um caso de miopatia miotubular. São discutidos estes resultados em relação aos achados de 56 casos desta moléstia consignados na literatura até 1978, sendo dada enfase à etiopatogenia.

  3. O ensino de auditoria em Angola estudo de caso

    OpenAIRE

    Capita, Francisco Ernesto

    2015-01-01

    Trabalho de Projecto apresentado ao Instituto de Contabilidade e Administração do Porto para a obtenção do grau de Mestre em Auditoria, sob orientação da Professora Doutora Alcina Augusta de Sena Portugal Dias Esta pesquisa tem como objectivo contribuir para a melhoria da formação dos potenciais auditores formados a partir das Instituições de Ensino Superior (IES) em Angola, tendo em conta as expectativas actuais bem como os desafios do mercado. Trata-se de um estudo de caso considerado so...

  4. Sintese, estudos estruturais e reatividade de naftoquinoniminas estaveis

    OpenAIRE

    Luiz Antonio Mazzini Fontoura

    1989-01-01

    Novas naftoquinoniminas estáveis foram sintetizadas por amonólise de naftoquinonas 2,5,8-trissubstituí das. Derivados dos novos compostos foram obtidos por reações de metilação. acetilação. condensação com cetonas e cicloadição com ciclopentadieno. Um estudo de tautomeria quinonimina-quinona através da técnica de UV-visível foi também realizado. New stable naphthoquinonimines were synthesised by ammonolysis of 2.5.8-trisubstituted naphthoquinones. Derivatives of the new compounds were obta...

  5. Marketing educacional: um estudo comparativo das atividades de marketing

    OpenAIRE

    Marta Maria Cunha Carneiro

    2015-01-01

    A revisão teórica apontou uma visão geral dos temas de marketing e educação por meio da cronologia histórica, da discussão conceitual, da relevância teórica e prática de cada assunto, dos principais desafios para pesquisa e o desenvolvimento do tema marketing educacional. Identificou-se e discutiu-se as atividades de marketing desenvolvidas nas instituições de ensino superior à luz dos fundamentos teóricos. A metodologia abordou os aspectos relacionados ao protocolo do estudo de caso e uma pe...

  6. Trajetória dos estudos de velhice no Brasil

    OpenAIRE

    Barros,Myriam Moraes Lins de

    2006-01-01

    Este artigo pretende traçar a trajetória das pesquisas antropológicas sobre velhice realizadas no Brasil desde a década de 1970, e apresentar as discussões atuais e seus desdobramentos em projetos de investigação. Dentro do campo de estudos sobre velhice foram escolhidas algumas temáticas: identidade social, memória, trajetória de vida, sociabilidade, espaço urbano, trabalho e aposentadoria, gênero, família e corpo. O recorte histórico procurou apontar as questões teóricas que foram sendo inc...

  7. Estudos sobre a estabilidade do desenho da figura humana (DHF)

    OpenAIRE

    Taborda, Alejandra; UNIVERSIDAD NACIONAL DE SAN LUIS; Barbenza, Claribel M. de; UNIVERSIDAD NACIONAL DE SAN LUIS

    2008-01-01

    Com o intuito de pesquisar a estabilidade do desenho da figura humana (DHF) e a pertinência das modificações feitas pela autora deste trabalho, comparam-se as normas de revalidação para crianças de 5 e 6 anos elaboradas por Koppitz (1968), e as desenvolvidas em Ottawa por Groves e Fried (1991) com as elaboradas por Taborda-Barbenza em San Luis, Mendoza e San Juan (Argentina, 1993). Este estudo comparativo realizou-se também em 127 crianças de 4 anos de San Luis e Villa Mercedes, considerando ...

  8. Dançaterapia no autismo: um estudo de caso

    OpenAIRE

    Teixeira-Machado,Lavinia

    2015-01-01

    O autismo é uma das desordens neurológicas mais comuns que afetam o desenvolvimento neuropsicomotor de crianças. Intervenções terapêuticas podem intervir nos transtornos de comunicação e nos comportamentos estereotipados, desse modo a dança, como terapia, pode ativar vias sensoriais que viabilizam o aprimoramento do gesto. Este estudo visou observar os efeitos da dançaterapia no desempenho motor e gestual, no equilíbrio corporal e na marcha, bem como na qualidade de vida de um adolescente com...

  9. Kinetics and Structure of Refractory Compounds and AlloysObtained by Mechanical Alloying

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Refractory compounds are material with interesting properties for structural applications. However, the processing of such material is a great challenge because of their high melting temperature and limited ductility. Mechanical alloying is a novel technique of producing refractory compounds with specific properties. Kinetical and structural peculiarities of refractory compounds and alloys obtained by mechanical alloying are discussed.

  10. Spark alloying of VK8 and T15K6 hard alloys

    Science.gov (United States)

    Kuptsov, S. G.; Fominykh, M. V.; Mukhinov, D. V.; Magomedova, R. S.; Nikonenko, E. A.; Pleshchev, V. P.

    2015-08-01

    A method is developed to restore the service properties of VK hard alloy plates using preliminary carburizing followed by spark alloying with a VT1-0 alloy. The phase composition is studied as a function of the spark treatment time.

  11. Alloying Solid Solution Strengthening of Fe-Ga Alloys: A First-Principle Study

    Science.gov (United States)

    2006-01-01

    effect from alloying additions of Nb, Mo, V, Cr and Co in cubic solid solution of Fe-Ga alloys. Mayer bond order "BO" values were used to evaluate the...that transition metal Nb achieves the best strengthening effect in Fe-Ga alloys. The solid solution strengthening follows a trend from larger to

  12. High toughness-high strength iron alloy

    Science.gov (United States)

    Stephens, J. R.; Witzke, W. R. (Inventor)

    1980-01-01

    An iron alloy is provided which exhibits strength and toughness characteristics at cryogenic temperatures. The alloy consists essentially of about 10 to 16 percent by weight nickel, about 0.1 to 1.0 percent by weight aluminum, and 0 to about 3 percent by weight copper, with the balance being essentially iron. The iron alloy is produced by a process which includes cold rolling at room temperature and subsequent heat treatment.

  13. The Fatigue of Powder Metallurgy Alloys.

    Science.gov (United States)

    2014-09-26

    v1o -2- MATERIALS AND TESTS Table 1 provides a complete listing of the alloys studied in this program together with their chemical compositions ...use can minimize material waste and minimize machining costs. In addition there is the potential for the development of more fine-grained and...out under fully reversed loading conditions in the high cycle range with smooth specimens. X7090 and X7091 are P/M alloys, 7075 is an ingot alloy

  14. Aspects of precipitation in alloy Inconel 718

    OpenAIRE

    Azadian, Saied

    2004-01-01

    A study was made of the microstructure of the Ni-base alloy Inconel 718 with emphasis on the precipitation and stability of intermetallic phases as affected by heat treatments. In addition the effect of the precipitation on selected mechanical properties namely hardness, creep notch sensitivity and hot ductlity were investigated. The materials studied were a spray-formed version and three wrought versions of the alloy. The spray-formed version of the alloy was of interest since it exhibited a...

  15. Advanced powder metallurgy aluminum alloys and composites

    Science.gov (United States)

    Lisagor, W. B.; Stein, B. A.

    1982-01-01

    The differences between powder and ingot metallurgy processing of aluminum alloys are outlined. The potential payoff in the use of advanced powder metallurgy (PM) aluminum alloys in future transport aircraft is indicated. The national program to bring this technology to commercial fruition and the NASA Langley Research Center role in this program are briefly outlined. Some initial results of research in 2000-series PM alloys and composites that highlight the property improvements possible are given.

  16. The oxidation and corrosion of ODS alloys

    Science.gov (United States)

    Lowell, Carl E.; Barrett, Charles A.

    1990-01-01

    The oxidation and hot corrosion of high temperature oxide dispersion strengthened (ODS) alloys are reviewed. The environmental resistance of such alloys are classified by oxide growth rate, oxide volatility, oxide spalling, and hot corrosion limitations. Also discussed are environmentally resistant coatings for ODS materials. It is concluded that ODS NiCrAl and FeCrAl alloys are highly oxidation and corrosion resistant and can probably be used uncoated.

  17. Oxidation And Hot Corrosion Of ODS Alloy

    Science.gov (United States)

    Lowell, Carl E.; Barrett, Charles A.

    1993-01-01

    Report reviews oxidation and hot corrosion of oxide-dispersion-strengthened (ODS) alloys, intended for use at high temperatures. Classifies environmental resistances of such alloys by rates of growth of oxides, volatilities of oxides, spalling of oxides, and limitations imposed by hot corrosion. Also discusses environmentally resistant coatings for ODS materials. Concludes ODS NICrAl and FeCrAl alloys highly resistant to oxidation and corrosion and can be used uncoated.

  18. Alloy nanoparticle synthesis using ionizing radiation

    Science.gov (United States)

    Nenoff, Tina M.; Powers, Dana A.; Zhang, Zhenyuan

    2011-08-16

    A method of forming stable nanoparticles comprising substantially uniform alloys of metals. A high dose of ionizing radiation is used to generate high concentrations of solvated electrons and optionally radical reducing species that rapidly reduce a mixture of metal ion source species to form alloy nanoparticles. The method can make uniform alloy nanoparticles from normally immiscible metals by overcoming the thermodynamic limitations that would preferentially produce core-shell nanoparticles.

  19. Cobalt-Base Alloy Gun Barrel Study

    Science.gov (United States)

    2014-07-01

    are presented in Section 5. 2. Materials and methods The composition of the cobalt -base alloy (CBA) is presented in Table 1. The production of this... Cobalt -Base Alloy Gun Barrel Study by William S. de Rosset and Jonathan S. Montgomery ARL-RP-0491 July 2014 A reprint...21005-5069 ARL-RP-0491 July 2014 Cobalt -Base Alloy Gun Barrel Study William S. de Rosset and Jonathan S. Montgomery Weapons and Materials

  20. Deformation Driven Alloying and Transformation

    Science.gov (United States)

    2015-03-03

    Rolling, Acta Materiala (08 2014) Zhe Wang , John H Perepezko, David Larson, David Reinhard. Mixing Behaviors in Cu/Ni and Ni/V Multilayers Induced...by Cold Rolling, Journal of Alloys and Compounds (07 2014) Zhe Wang , John H. Perepezko. Deformation-Induced Nanoscale Mixing Reactions in Cu/Ni...FTE Equivalent: Total Number: Discipline Zhe Wang 0.50 0.50 1 Names of Post Doctorates Names of Faculty Supported Names of Under Graduate students

  1. Titanium alloys Russian aircraft and aerospace applications

    CERN Document Server

    Moiseyev, Valentin N

    2005-01-01

    This text offers previously elusive information on state-of-the-art Russian metallurgic technology of titanium alloys. It details their physical, mechanical, and technological properties, as well as treatments and applications in various branches of modern industry, particularly aircraft and aerospace construction. Titanium Alloys: Russian Aircraft and Aerospace Applications addresses all facets of titanium alloys in aerospace and aviation technology, including specific applications, fundamentals, composition, and properties of commercial alloys. It is useful for all students and researchers interested in the investigation and applications of titanium.

  2. New aluminium alloys with high lithium content

    Energy Technology Data Exchange (ETDEWEB)

    Schemme, K.; Velten, B.

    1989-06-01

    Since the early 80's there have been made great efforts to replace the high strength aluminium alloys for the aircraft and space industry by a new generation of aluminium-lithium alloys. The attractivity of this kind of alloys could be increased by a further reduction of their density, caused by an increasing lithium content (/ge/ 5 wt.% Li). Therefore binary high-lithium containing alloys with low density are produced and metallografically investigated. A survey of their strength and wear behavior is given by using tensile tests and pin abrasing tests. (orig.).

  3. Casting Characteristics of Aluminum Die Casting Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Makhlouf M. Makhlouf; Diran Apelian

    2002-02-05

    The research program investigates the casting characteristics of selected aluminum die casting alloys. Specifically, the alloys' tendencies towards die soldering and sludge formation, and the alloys' fluidity and machinability are evaluated. It was found that: When the Fe and Mn contents of the alloy are low; caution has to be taken against possible die soldering. When the alloy has a high sludge factor, particularly a high level of Fe, measures must be taken to prevent the formation of large hardspots. For this kind of alloy, the Fe content should be kept at its lowest allowable level and the Mn content should be at its highest possible level. If there are problems in die filling, measures other than changing the alloy chemistry need to be considered first. In terms of alloy chemistry, the elements that form high temperature compounds must be kept at their lowest allowable levels. The alloys should not have machining problems when appropriate machining techniques and machining parameters are used.

  4. Ultralow-fatigue shape memory alloy films

    National Research Council Canada - National Science Library

    Chluba, C; Ge, W; Lima de Miranda, R; Strobel, J; Kienle, L; Quandt, E; Wuttig, M

    2015-01-01

    Functional shape memory alloys need to operate reversibly and repeatedly. Quantitative measures of reversibility include the relative volume change of the participating phases and compatibility matrices for twinning...

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

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

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

  6. Nanodispersed boriding of titanium alloy

    Directory of Open Access Journals (Sweden)

    Kateryna O. Kostyk

    2015-12-01

    Full Text Available The problem of improving the operational reliability of machines is becoming increasingly important due to the increased mechanical, thermal and other loads on the details. There are many surface hardening methods for machines parts which breakdown begins with surface corruption. The most promising methods are chemo-thermal treatment. Aim: The aim of this work is to study the impact of boriding on the structure and properties of titanium alloy. Materials and Methods: The material of this study is VT3-1 titanium alloy. The boriding were conducted using nanodispersed powder blend based on boric substances. Results: It is established that boriding of paste compounds allows obtaining the surface hardness within 30...29 GPa and with declining to 27...26 GPa in layer to the transition zone (with total thickness up to 110 μm owing to changes of the layer phase composition where Ti2B, TiB, TiB2 titanium borides are formed. The increasing of chemical-thermal treatment time from 15 minutes to 2 hours leads to thickening of the borated layer (30...110 µm and transition zone (30...190 µm. Conclusions: Due to usage of nanodispersed boric powder, the boriding duration is decreasing in 2...3 times. This allows saving time and electric energy. The developed optimal mode of boriding the VT3-1 titanium alloy allows obtaining the required operational characteristics and to combine the saturation of the surface layer with atomic boron and hardening.

  7. Pack cementation coatings for alloys

    Energy Technology Data Exchange (ETDEWEB)

    He, Yi-Rong; Zheng, Minhui; Rapp, R.A. [Ohio State Univ., Columbus, OH (United States)

    1996-08-01

    The halide-activated pack cementation process was modified to produce a Ge-doped silicide diffusion coating on a Cr-Cr{sub 2}Nb alloy in a single processing step. The morphology and composition of the coating depended both on the composition of the pack and on the composition and microstructure of the substrate. Higher Ge content in the pack suppressed the formation of CrSi{sub 2} and reduced the growth kinetics of the coating. Ge was not homogeneously distributed in the coatings. In cyclic and isothermal oxidation in air at 700 and 1050{degrees}C, the Ge-doped silicide coating protected the Cr-Nb alloys from significant oxidation by the formation of a Ge-doped silica film. The codeposition and diffusion of aluminum and chromium into low alloy steel have been achieved using elemental Al and Cr powders and a two-step pack cementation process. Sequential process treatments at 925{degrees}C and 1150{degrees}C yield dense and uniform ferrite coatings, whose compositions are close to either Fe{sub 3}Al or else FeAl plus a lower Cr content, when processed under different conditions. The higher content of Al in the coatings was predicted by thermodynamic calculations of equilibrium in the gas phase. The effect of the particle size of the metal powders on the surface composition of the coating has been studied for various combinations of Al and Cr powders.

  8. Microbial corrosion of aluminum alloy.

    Science.gov (United States)

    Yang, S S; Chen, C Y; Wei, C B; Lin, Y T

    1996-11-01

    Several microbes were isolated from the contaminated fuel-oil in Taiwan and the microbial corrosion of aluminum alloy A356-T6 was tested by MIL-STD-810E test method. Penicillium sp. AM-F5 and Cladosporium resinac ATCC 22712 had significant adsorption and pitting on the surface of aluminum alloy, Pseudomonas acruginosa AM-B5 had weak adsorption and some precipitation in the bottom, and Candida sp. AM-Y1 had the less adsorption and few cavities formation on the surface. pH of the aqueous phase decreased 0.3 to 0.7 unit for 4 months of incubation. The corrosion of aluminum alloy was very significant in the cultures of Penicillium sp. AM-F2, Penicillium sp. AM-F5 and C. resinac ATCC 22712. The major metabolites in the aqueous phase with the inoculation of C. resinac were citric acid and oxalic acid, while succinic acid and fumaric acid were the minors.

  9. O colecionador de vinil : um estudo vídeo-etnográfico

    OpenAIRE

    João Pedro dos Santos Fleck

    2008-01-01

    O presente estudo tem por objetivo fornecer uma maior compreensão acerca do que motiva o comportamento de compra de coleção, utilizando como objeto de estudo, os colecionadores de discos de vinil da cidade de Porto Alegre. A questão central de pesquisa pode ser definida como: quais as causas motivadoras do consumo de discos vinil? A importância do estudo se justifica devido ao fato da existência de lacunas nos estudos sobre comportamento de consumo de coleção e sobre a tendência nostálgica in...

  10. Estudo sobre a prevalência do tabagismo entre adolescentes no Brasil

    OpenAIRE

    Dantas, Deborah Rose Galvão

    2013-01-01

    p. 1-121 Objetivo:Observar a prevalência do tabagismo entre adolescentes no Brasil;analisar fatores de risco ao tabagismo.Métodos:Estudo descritivo observacional e estudo de corte transversal. Foram pesquisados estudos de corte transversal ou coorte nos últimos 40anos,contendo percentuais de prevalência e/ou experimentação nos bancos de dados:MEDLINE, SciELO, LILACS e PubMeD; por busca ativa e comunicados oficiais,sendo selecionados 84 trabalhos.Foi realizado estudo de corte transversal de...

  11. Sintomas depressivos em crianças: estudos com duas versões do CDI

    Directory of Open Access Journals (Sweden)

    Miriam Cruvinel

    Full Text Available O objetivo deste estudo foi identificar o número de crianças com sintomas depressivos em duas amostras de estudantes da cidade de campinas. Utilizou-se, no estudo 1, a versão brasileira do Inventário de Depressão Infantil (CDI e, no estudo 2, a versão original. Do estudo 1, realizado em 2001, participaram 169 estudantes de 3ª, 4ª e 5ª séries, e, do estudo 2, conduzido em 2005, 157 alunos de 3ª e 4ª séries. A prevalência de sintomatologia depressiva no estudo 1 foi de 3,55%, e, no estudo 2, de 17%. Em ambos os estudos, não foram encontradas diferenças significativas entre a média no CDI em relação às variáveis demográficas. conclui-se pela necessidade de mais estudos nacionais de prevalência no ensino fundamental e de esforços direcionados não só para a identificação dos fatores de risco, de proteção e das variáveis associadas mas também do refinamento dos instrumentos de medidas da depressão infantil.

  12. Perspectivas psicossociais para o estudo do cotidiano de trabalho

    Directory of Open Access Journals (Sweden)

    Fábio de Oliveira

    2014-04-01

    Full Text Available Este estudo teve por objetivo analisar o debate e o aprofundamento teórico e metodológico desenvolvido nos estudos sobre a vida cotidiana no trabalho. A investigação partiu do diálogo interdisciplinar entre a antropologia do trabalho, a ergologia e a psicologia social do trabalho e sistematizou as contribuições mútuas entre esses campos científicos, suas aproximações e seus afastamentos da tematização e da apropriação da atividade humana no trabalho sob a perspectiva do cotidiano. A análise comparativa destacou eixos que diferenciam as formas de aproximação ao objeto, que se referem às relações estabelecidas entre saberes práticos e técnico-científicos e aos modos de intervenção sobre as situações de trabalho. As abordagens comparativas compartilham o interesse em conhecer o trabalho real, o valor conferido aos conhecimentos dos trabalhadores e a sensibilidade às dimensões micropolíticas do cotidiano. Conclui-se que a localização em cada um desses eixos depende da maior ou menor filiação às tradições da antropologia ou da ergonomia.

  13. Revendo estudos sobre a assistência domiciliar ao idoso

    Directory of Open Access Journals (Sweden)

    Andreza Aparecida de Lima

    2013-06-01

    Full Text Available A assistência domiciliar apresenta-se como uma recente modalidade de cuidado aos idosos, sobretudo no Brasil, e vem sendo inserida nas políticas públicas. Este estudo busca identificar produções científicas acerca da assistência domiciliar, a fim de verificar quais as contribuições desta na dinâmica social do idoso. A pesquisa foi realizada nas bases de dados LILACS e MEDLINE, com artigos publicados entre os anos de 2001 a 2011, nos idiomas português e inglês. A combinação de palavras-chave utilizada foi home care e elderly, elderly e care, e elderly e caregiver, e as correspondentes em português. A discussão dos resultados evidenciou a importância da assistência domiciliar, principalmente para idosos solitários ou negligenciados. A revisão revelou poucos estudos referentes à assistência domiciliar na dinâmica social de idosos e a necessidade de ampliar as discussões para além do campo da saúde.

  14. Para um estudo psicológico das virtudes morais

    Directory of Open Access Journals (Sweden)

    La Taille Yves de

    2000-01-01

    Full Text Available O propósito deste artigo é defender a importância de estudos psicológicos das virtudes morais (como generosidade, coragem, humildade, fidelidade etc.. Tal defesa é realizada de várias formas. Do ponto de vista filosófico, o tema das virtudes não somente é clássico (Ver Aristóteles, por exemplo como tem sido rediscutido por autores contemporâneos descontentes com as limitações da ética moderna, em geral baseada no conceito de direito. Do ponto de vista psicológico, o autor defende a idéia segundo a qual as virtudes morais não somente participam da gênese da moralidade, como representam traços de caráter essenciais à coesão da personalidade moral. Tal perspectiva está, de certa forma, anunciada na obra de Piaget sobre o juízo moral, como em autores outros como Tugendhat. Ela está também presente nos estudos sobre a relação entre o sentimento de vergonha e a ética. Finalmente, aponta-se que, no que se refere à educação moral, as virtudes podem representar um tema rico e sugestivo para a reflexão das crianças e adolescentes.

  15. Marketing, Propaganda e Publicidade - um estudo dos termos no Brasil

    Directory of Open Access Journals (Sweden)

    Miguel Arantes Normanha Filho

    2007-12-01

    Full Text Available Este estudo contribui para a verificação empírica das diversas interpretações e aplicabilidades dadas aos pares de termos marketing e propaganda, propaganda e publicidade, em especial pela forma e uso como se fossem sinônimos, num contexto de negócios que pode acarretar prejuízos às empresas. O estudo parte da observação de que utilizar marketing e propaganda como sinônimos não é uma questão semântica, mas conceitual, em que a aplicação de uma ferramenta [propaganda] específica, em detrimento de uma filosofia do negócio [marketing], leva empresários [decisores] a equívocos estratégicos, que influenciam e comprometem o capital de giro e, conseqüentemente, a saúde econômico-financeira da empresa.

  16. Perspectivas de estudos comparados a partir da aplicação da escala Likert de 4 pontos: um estudo metodológico da pesquisa TALIS

    OpenAIRE

    Rose Meri Trojan; Robson Sipraki

    2015-01-01

    Este estudo analisa a utilização da Escala Likert na pesquisa Teaching and Learning International Survey (TALIS). O tema justifica-se pelo uso recorrente da estatística nas pesquisas educacionais, especialmente, aquelas que permitem estudos comparados internacionais. O objetivo é avaliar análises apresentadas no relatório TALIS (OCDE, 2009) e verificar as perspectivas do uso da Escala Likert em estudos que utilizam os resultados desta pesquisa. Metodologicamente, partiu-se dos fundamentos est...

  17. Data set for diffusion coefficients of alloying elements in dilute Mg alloys from first-principles

    Directory of Open Access Journals (Sweden)

    Bi-Cheng Zhou

    2015-12-01

    Full Text Available Diffusion coefficients of alloying elements in Mg are critical for the development of new Mg alloys for lightweight applications. Here we present the data set of the temperature-dependent dilute tracer diffusion coefficients for 47 substitutional alloying elements in hexagonal closed packed (hcp Mg calculated from first-principles calculations based on density functional theory (DFT by combining transition state theory and an 8-frequency model. Benchmark for the DFT calculations and systematic comparison with experimental diffusion data are also presented. The data set refers to “Diffusion coefficients of alloying elements in dilute Mg alloys: A comprehensive first-principles study” by Zhou et al. [1].

  18. The Properties of 7xxx Series Alloys Formed by Alloying Additions

    Directory of Open Access Journals (Sweden)

    Kwak Z.

    2015-06-01

    Full Text Available Currently there is a constant development in the field of aluminium alloys engineering. This results from, i.a., better understanding of the mechanisms that direct strengthening of these alloys and the role of microalloying. Now it is microalloying in aluminum alloys that is receiving a lot of attention. It affects substantially the macro- and microstructure and kinetics of phase transformation influencing the properties during production and its exploitation. 7xxx series aluminum alloys, based on the Al-Zn-Mg-Cu system, are high-strength alloys, moreover, the presence of Zr and Sr further increases their strength and improves resistance to cracking.

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

    Institute of Scientific and Technical Information of China (English)

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

    2004-01-01

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

  20. Iron-based amorphous alloys and methods of synthesizing iron-based amorphous alloys

    Science.gov (United States)

    Saw, Cheng Kiong; Bauer, William A.; Choi, Jor-Shan; Day, Dan; Farmer, Joseph C.

    2016-05-03

    A method according to one embodiment includes combining an amorphous iron-based alloy and at least one metal selected from a group consisting of molybdenum, chromium, tungsten, boron, gadolinium, nickel phosphorous, yttrium, and alloys thereof to form a mixture, wherein the at least one metal is present in the mixture from about 5 atomic percent (at %) to about 55 at %; and ball milling the mixture at least until an amorphous alloy of the iron-based alloy and the at least one metal is formed. Several amorphous iron-based metal alloys are also presented, including corrosion-resistant amorphous iron-based metal alloys and radiation-shielding amorphous iron-based metal alloys.

  1. Grain refinement of 7075Al alloy microstructures by inoculation with Al-Ti-B master alloy

    Science.gov (United States)

    Hotea, V.; Juhasz, J.; Cadar, F.

    2017-05-01

    This paper aims to bring some clarification on grain refinement and modification of high strength alloys used in aerospace technique. In this work it was taken into account 7075 Al alloy, and the melt treatment was carried out by placing in the form of master alloy wire ternary AlTiB the casting trough at 730°C. The morphology of the resulting microstructures was characterized by optical microscopy. Micrographs unfinished and finished with pre-alloy containing ternary Al5Ti1B evidence fine crystals, crystal containing no columnar structure and highlights the size of the dendrites, and intermetallic phases occurring at grain boundaries in Al-Zn-Mg-Cu alloy. It has been found that these intermetallic compounds are MgZn2 type. AlTiB master alloys finishing ensures a fine eutectic structure, which determines the properties of hardware and improving the mechanical properties of aluminum alloys used in aeronautical engineering.

  2. A interface estudos discursivos e estudos ergológicos =The interface between discursive studies and ergologic studies

    Directory of Open Access Journals (Sweden)

    Silva, Maria Cecília Pérez de Souza e

    2014-01-01

    Full Text Available Este artigo tem por objetivo explicitar caminhos teórico-metodológicos aos quais temos recorrido a fim de consolidar o estudo das relações linguagem/trabalho, mais especificamente dos estudos discursivos e ergológicos. Adotar a perspectiva discursiva implica considerar a língua não como instrumento informacional, transparente, mas como polissêmica e opaca. Implica também aceitar que a discursividade define uma ordem própria diversa da materialidade da linguagem, mas que se realiza na língua. Compartilhar a abordagem ergológica significa pensar a atividade de trabalho como o encontro entre as normas e os seres humanos capazes, por suas escolhas, de traduzi-las em cada situação. Ambas as abordagens encontram abrigo no paradigma indiciário, que supõe a existência de um rigor flexível e elástico. Flexível porque não exige o estabelecimento de uma verdade única, universal e inquestionável; elástico porque não prescinde do rigor, não abre mão da interpretação.

  3. Medidas de rede e apoio social no Estudo Pró-Saúde: pré-testes e estudo piloto

    Directory of Open Access Journals (Sweden)

    Dóra Chor

    Full Text Available Neste artigo, relatamos a metodologia de seleção de perguntas sobre rede e apoio social, incluídas em um estudo de coorte de 4.030 funcionários de uma universidade pública no Rio de Janeiro. Em primeiro lugar, a adequação de conceitos foi explorada em discussões de grupos de voluntários. Em seguida, o questionário do Medical Outcomes Study foi submetido a procedimentos padronizados de tradução e versão. As perguntas foram a seguir avaliadas em cinco etapas de pré-testes e estudo piloto. Nenhuma pergunta apresentou proporção de não-resposta acima de 5%. Os coeficientes de correlação de Pearson entre os itens foram distantes de zero e da unidade; a correlação entre cada item e o escore de sua dimensão foi superior a 0,80 em quase todos os casos. Finalmente, os coeficientes Alpha de Cronbach foram superiores a 0,70 em todas as dimensões. Os resultados sugerem que aspectos de rede e apoio social serão mensurados adequadamente, permitindo a investigação de suas associações com desenlaces relacionados à saúde em um grupo populacional no Brasil.

  4. METHOD AND ALLOY FOR BONDING TO ZIRCONIUM

    Science.gov (United States)

    McCuaig, F.D.; Misch, R.D.

    1960-04-19

    A brazing alloy can be used for bonding zirconium and its alloys to other metals, ceramics, and cermets, and consists of 6 to 9 wt.% Ni, 6 to 9 wn~.% Cr, Mo, or W, 0 to 7.5 wt.% Fe, and the balance Zr.

  5. Zirconium alloys produced by recycling zircaloy tunings

    Energy Technology Data Exchange (ETDEWEB)

    Gamba, N.S. [Instituto de Investigaciones en Catálisis y Petroquímica, INCAPE (FIQ, UNL–CONICET), Santiago del Estero 2829, 3000 Santa Fe (Argentina); Carbajal-Ramos, I.A. [Centro Atómico Bariloche, CNEA e Instituto Balseiro, Universidad Nacional de Cuyo, Av. Bustillo 9500, 8400 Bariloche (Argentina); Ulla, M.A.; Pierini, B.T. [Instituto de Investigaciones en Catálisis y Petroquímica, INCAPE (FIQ, UNL–CONICET), Santiago del Estero 2829, 3000 Santa Fe (Argentina); Gennari, F.C., E-mail: gennari@cab.cnea.gov.ar [Centro Atómico Bariloche, CNEA e Instituto Balseiro, Universidad Nacional de Cuyo, Av. Bustillo 9500, 8400 Bariloche (Argentina)

    2013-11-25

    Highlights: •Zr–Ti alloys were successfully produced by two-step procedure. •Zircaloy tunings were used as a valuable source of Zr. •Zircaloy tunings and Ti powders was milled under hydrogen to produce hydride powders. •Hydride powders were decomposed by heating at 900 °C to synthesize the Zr-based alloy. •The procedure could be extended to the production of other Zr-based alloys. -- Abstract: Zircaloy chips were recycled to successfully produce Zr–Ti alloys with bcc structure and different compositions. The procedure developed involves two steps. First, the reactive mechanical alloying (RMA) of the zircaloy tunings and Ti powders was performed to produce metal hydride powders, with a high refinement of the microstructure and a Zr–Ti homogeneous composition. Second, the metal hydride powders were thermally decomposed by heating up to 900 °C to synthesize the Zr-based alloy with a selected composition. The change in the nature of the powders from ductile to brittle during milling avoids both cold working phenomena between the metals and the use of a control agent. A minimum milling time is necessary to produce the solid solution with the selected composition. The microstructure and structure of the final alloys obtained was studied. The present procedure could be extended to the production of Zr-based alloys with the addition of other metals different from Ti.

  6. Measurement of oxide adherence to PFM alloys.

    Science.gov (United States)

    Mackert, J R; Parry, E E; Hashinger, D T; Fairhurst, C W

    1984-11-01

    A method has been reported for evaluating adherence of an oxide to its substrate metal to a maximum value of about 40 MPa. Oxidized alloy plates were cemented between two aluminum cylinders with a high-strength cyanoacrylate cement and loaded in tension until failure occurred either at the oxide/metal interface, within the oxide layer, or in the cement itself. Significant differences were found among the oxide adherence values obtained from different PFM alloys. The oxides formed on five of the alloys exhibited adherence strengths in excess of the published value for cohesive strength of dental opaque porcelain, indicating that they possess sufficient adherence to act as the transition zone between the porcelain and the alloy. In addition, a correspondence was found between the quality of porcelain bond for a given alloy and its oxide adherence strength. These results remove the principal objection to the oxide-layer theory of porcelain bonding in dental alloy systems and emphasize the importance of oxide adherence in the establishment of a bond. It is therefore suggested that future work devoted to porcelain-metal bonding should seek to elucidate the mechanism of oxide adherence to PFM alloys and explore the development of new alloys which form adherent oxides.

  7. Progress in High-Entropy Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Michael C

    2013-12-01

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

  8. STRUCTURE OF LIQUID CESIUM LEAD ALLOYS

    NARCIS (Netherlands)

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

    1993-01-01

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

  9. Castable nickel aluminide alloys for structural applications

    Science.gov (United States)

    Liu, Chain T.

    1992-01-01

    The specification discloses nickel aluminide alloys which include as a component from about 0.5 to about 4 at. % of one or more of the elements selected from the group consisting of molybdenum or niobium to substantially improve the mechanical properties of the alloys in the cast condition.

  10. Design optimization of shape memory alloy structures

    NARCIS (Netherlands)

    Langelaar, M.

    2006-01-01

    This thesis explores the possibilities of design optimization techniques for designing shape memory alloy structures. Shape memory alloys are materials which, after deformation, can recover their initial shape when heated. This effect can be used for actuation. Emerging applications for shape memory

  11. Design optimization of shape memory alloy structures

    NARCIS (Netherlands)

    Langelaar, M.

    2006-01-01

    This thesis explores the possibilities of design optimization techniques for designing shape memory alloy structures. Shape memory alloys are materials which, after deformation, can recover their initial shape when heated. This effect can be used for actuation. Emerging applications for shape memory

  12. Ti-Pt Alloys form mechanical milling

    CSIR Research Space (South Africa)

    Nxumalo, S

    2009-12-01

    Full Text Available orthorhombic structure at a temperature of approximately 1000oC. The martensite phase results in shape memory effect being observed in this alloy at this temperature. Other alloys such as TiNi and TiPd have also been investigated for the martensitic...

  13. Friction Stir Welding of Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    FU Zhi-hong; HE Di-qiu; WANG Hong

    2004-01-01

    Friction stir welding(FSW), a new solid-state welding technology invited in the early 1990s,enables us weld aluminum alloys and titanium alloys etc. The processing of FSW, the microstructure in FSW alloysand the factors influencing weld quality are introduced. The complex factors affecting the properties are researched.

  14. Laser alloyed Al-Ni-Fe coatings

    CSIR Research Space (South Africa)

    Pityana, SL

    2008-10-01

    Full Text Available analysed by menas of X-ray diffraction (XRD), optical and scanning electron microscopy (SEM). It was found that when alloying with Fe-rich mixtures, the thin surface layers contained a number of cracks in the heat affected zones (HAZ). Alloying with Ni...

  15. Trends of Chinese RE Hydrogen Storage Alloys

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ Ⅰ . Status of Chinese RE Hydrogen Storage Alloys 1. R εt D of RE Hydrogen Storage Alloys in China AB5 hydrogen storage materials, taking rare earth mischmetals as raw materials, developed rapidly in China in recent years. Today, different countries attach importance to the development and application of the new environmental protection reproducible power sources.

  16. Alloys of clathrate allotropes for rechargeable batteries

    Science.gov (United States)

    Chan, Candace K; Miller, Michael A; Chan, Kwai S

    2014-12-09

    The present disclosure is directed at an electrode for a battery wherein the electrode comprises clathrate alloys of silicon, germanium or tin. In method form, the present disclosure is directed at methods of forming clathrate alloys of silicon, germanium or tin which methods lead to the formation of empty cage structures suitable for use as electrodes in rechargeable type batteries.

  17. Electroplating Zn-Al Alloy Technology

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The method of controlling separating anode and separating power source was used to perform orthogonal optimization for the parameters in electroplating Zn-Al alloy.The electroplating Zn-Al alloy technology was decided, in which the content of Al is about 12%-15%.

  18. Thermally activated martensite formation in ferrous alloys

    DEFF Research Database (Denmark)

    Villa, Matteo; Somers, Marcel A. J.

    2017-01-01

    Magnetometry was applied to investigate the formation of α/α´martensite in 13ferrous alloys during immersion in boiling nitrogen and during re-heating to room temperature at controlled heating rates in the range 0.0083-0.83 K s-1. Data showsthat in 3 of the alloys, those that form {5 5 7}γ...

  19. Otomycosis: a retrospective study Otomicoses: um estudo retrospectivo

    Directory of Open Access Journals (Sweden)

    Zélia Braz Vieira da Silva Pontes

    2009-06-01

    Full Text Available Otomycosis is a fungal infection of the external ear canal with only a few studies about its real frequence in Brazil. AIM: to evaluate otomycosis frequence and characteristics in patients with clinical suspicion of external otitis. STUDY DESIGN: Retrospective study with transversal cohort (2000-2006. MATERIALS AND METHODS:103 patients were assigned to mycological diagnosis (direct microscopic examination and culture. RESULTS: Otomycosis was diagnosed in 19.4% of the patients. Patient age varied from 2 to 66 years (an average of 23.5 years of age, and 60% of otomycosis cases were seen in women between 2 to 20 years of age. Chronic otitis, previous antibiotic therapy and the lack of cerumen were predisposing factors; itching, otalgia, otorrhea and hypoacusis were the symptoms reported by the patients. The most frequently isolated species were C. albicans (30%, C. parapsilosis (20%, A. niger (20%, A. flavus (10%, A. fumigatus (5%, C. tropicalis (5%, Trichosporon asahii (5% and Scedosporium apiospermum (5%. CONCLUSIONS: Otomycosis is endemic in João Pessoa-PB. Clinical exam and mycological studies are important for diagnostic purposes because otomycosis symptoms are not specific.Otomicose é uma infecção fúngica do conduto auditivo externo com poucos estudos sobre sua real frequência no Brasil. OBJETIVO: Avaliar a frequência e características das otomicoses em pacientes com suspeita clínica de otite externa. DESENHO DO ESTUDO: Estudo retrospectivo com corte transversal (2000-2006. MATERIAL E MÉTODOS: 103 pacientes foram atendidos para diagnóstico micológico (exame microscópico direto e cultivo. RESULTADOS: Otomicoses foram diagnosticadas em 19,4% dos pacientes. A idade desses pacientes variou de 2 a 66 anos (média de 23,5 anos e 60% das otomicoses foram observadas em mulheres entre 2 a 20 anos de idade. Otite crônica, antibioticoterapia prévia e ausência de cerume foram os fatores predisponentes e prurido otológico, otalgia

  20. Estudos de Comunidade e ciências sociais no Brasil

    Directory of Open Access Journals (Sweden)

    Nemuel da Silva Oliveira

    2011-12-01

    Full Text Available O objetivo deste artigo é fazer um balanço da literatura sobre os Estudos de Comunidade (EC no Brasil, destacando o contexto intelectual em que foram produzidos e os debates que suscitaram, especialmente entre as décadas de 1940 e 1960. Método de pesquisa em comunidades, oriundo da Antropologia, em investigações sobre o processo de mudança social, os EC estiveram em voga nos Estados Unidos entre os anos 1920 e 1950, tendo papel fundamental na institucionalização das Ciências Sociais no Brasil. Destacamos três aspectos na produção desses estudos no país, iniciando com uma abordagem conceitual: definições, origem e sua relação com temáticas marcantes nos anos 1950. Em seguida, privilegiamos os aspectos relacionados ao papel dos EC na história das Ciências Sociais no Brasil, com destaque para o processo de institucionalização das Ciências Sociais. Por fim, revisitamos os debates que tais estudos geraram entre os cientistas sociais quanto ao padrão de trabalho sociológico a ser desenvolvido naquele momento.The purpose of this article is to examine the literature about Community Studies(CS in Brazil, highlighting their intellectual context of production and the debates evoked by them, especially between the 1940's and 1960's. As a research method arising from Anthropology on communities in social change process, CS was used in United States between 1920's and 1950's, and played a fundamental role in the institutionalization of Social Sciences in Brazil. Three aspects are highlighted on CS production: first, in a conceptual approach, we discuss their definitions, origins and relation to main topics in the 1950's. The second aspect is related to the role of CS in the history of Social Sciences, especially their institutionalization process. By the end, we revisit the debates between social scientists about the sociological work standard to be developed at that time.

  1. Imagem organizacional: um estudo de caso sobre a PUC Minas.

    Directory of Open Access Journals (Sweden)

    Alexandre de Pádua Carrieri

    2008-06-01

    Full Text Available Esta pesquisa propôs conhecer a imagem corporativa, considerando sua importância para a administração das organizações no cenário atual de maior competitividade e de exigências por parte de segmentos do seu público. O estudo parte da formação da cultura e da identidade de uma organização, analisando estes itens como fundamentais na definição da imagem de uma instituição. Tomando a Pontifícia Universidade Católica de Minas Gerais - PUC Minas - enquanto objeto de estudo, utilizou-se como estratégia metodológica a pesquisa qualitativa, com a análise de conteúdo. O trabalho foi realizado em duas etapas: entrevistas com os gestores da Universidade e pesquisa de campo com segmentos de públicos de interesse tais como: professores e alunos de escolas de segundo grau, alunos de graduação e profissionais de recursos humanos. Observou-se que novas formas de relacionamento entre a organização e seus públicos de interesse foram criadas. Foram também implantados novos meios de comunicação – mais modernos, ágeis e editorialmente trabalhados – e estruturados novos processos de comunicação e interlocução, oportunizando melhor controle para a alta administração, da imagem da sua Universidade. Palavras-chave: Estudos organizacionais; imagem organizacional; universidade Abstract This research has purpose know a little more about corporative image, considering its importance to management of organizations in current context of higher competition and greater demand. This study came from the configuration of the culture and identity of organization, foreseeing those items as fundamentals to definition of any institution’s image. Taking the Pontifícia Universidade Católica de Minas Gerais - PUC Minas – as object of study, the content analysis was carried out through a qualitative research - the employed methodological strategy. The work was conducted in two stages: (I interviews with managers, and (II field research with

  2. Estudos sobre a toxicologia da ε-caprolactama

    Directory of Open Access Journals (Sweden)

    Marcus Vinicius Justo Bomfim

    2009-03-01

    Full Text Available A ε-caprolactama (CAP é um monômero precursor de polímeros denominados nylon 6. Esses polímeros destinam-se à produção de tapetes, vestuário e materiais plásticos tais como equipamentos, sistemas e componentes automotivos, conectores, além de embalagens plásticas. Resíduos de CAP podem migrar de embalagens plásticas de nylon 6 para os alimentos. Diante disso, foi de interesse realizar uma revisão dos efeitos relativos à exposição à CAP e o seu impacto sobre a saúde humana. Estudos epidemiológicos indicam a possibilidade da CAP causar inflamações oculares e cutâneas, além de irritações no sistema respiratório. Pode ocorrer ainda hipotensão, taquicardia, palpitações, rinorréia, ressecamento nasal, efeitos geniturinários e sobre a reprodução como distúrbios nas funções menstrual e ovariana, e complicações no parto; além de problemas neurológicos e hematológicos. Estudos com animais são consistentes com tais relatos. Os estudos de genotoxicidade in vitro e in vivo por via oral e intraperitoneal mostram em sua grande maioria, resultados negativos, bem como ausência de efeitos carcinogênicos em ratos e camundongos e sobre o desenvolvimento e reprodução em ratos e coelhos.ε -Caprolactam (CAP is a precursor monomer of nylon 6 polymers. Nylon 6 is used in the manufacture of carpets, clothes and plastic materials, such as equipment, systems and automotive components, connectors and plastic packaging. CAP residues can migrate from nylon 6 plastic packaging to foods. Given this fact, this review was realized concerning the effects of CAP exposure and its impact on human health. Epidemiological studies indicate that CAP could cause ocular, cutaneous and respiratory irritations, as well as hypotension, tachycardia, palpitations, rhinorrhea, nose dryness, neurological and blood problems, and genitourinary and reproductive effects, such as alterations in ovarian-menstrual functions and pregnancy

  3. Corrosion resistance improvement of titanium base alloys

    Energy Technology Data Exchange (ETDEWEB)

    Popa, Mihai V.; Vasilescu, Ecaterina; Drob, Paula; Vasilescu, Cora; Drob, Silviu I., E-mail: ec_vasilescu@yahoo.co [Institute of Physical Chemistry ' Ilie Murgulescu' , Bucharest (Romania); Mareci, Daniel [Technical University ' Gh. Asachi' , Iasi (Romania); Rosca, Julia C. Mirza [Las Palmas de Gran Canaria University, Tafira (Spain). Mechanical Engineering Dept.

    2010-07-01

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

  4. [Use of titanium alloys for medical instruments].

    Science.gov (United States)

    Feofilov, R N; Chirkov, V K; Levin, M V

    1977-01-01

    On the ground of an analysis into properties of titanium and its alloys the fields of their possible utilization for making various medical instruments are proposed. Because of their insufficient hardness and wear-resistance the titanium alloys cannot be recommended for making medical instruments with thin cutting edges. For the reasons of their insufficient strength, low wear-resistance and substandard modulus of elasticity, it is inexpedient to use titanium alloys in making many types of clamping medical instruments. Nor is it advisable to employ titanium alloys in handles of the instruments, for this may lead to a contact corrosion of their working parts. The use of titanium alloys is recommended for making bone-joining members, retracting medical instruments, of the spatula and speculum types, some kinds of non-magnetic pincers and ultrasonic medical instruments.

  5. Corrosion resistance improvement of titanium base alloys

    Directory of Open Access Journals (Sweden)

    Mihai V. Popa

    2010-01-01

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

  6. Mechanical behaviour of aluminium-lithium alloys

    Indian Academy of Sciences (India)

    N Eswara Prasad; A A Gokhale; P Rama Rao

    2003-02-01

    Aluminium-lithium alloys hold promise of providing a breakthrough response to the crying need for lightweight alloys for use as structurals in aerospace applications. Considerable worldwide research has gone into developing a range of these alloys over the last three decades. As a result, substantial understanding has been developed of the microstructure-based micromechanisms of strengthening, of fatigue and fracture as well as of anisotropy in mechanical properties. However, these alloys have not yet greatly displaced the conventionally used denser Al alloys on account of their poorer ductility, fracture toughness and low cycle fatigue resistance. This review aims to summarise the work pertaining to study of structure and mechanical properties with a view to indicate the directions that have been and can be pursued to overcome property limitations.

  7. Internal chlorination of Ni-Cr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Berztiss, D.; Hennesen, K.; Grabke, H.J. [Max-Planck-Institut fuer Eisenforschung GmbH, Duesseldorf (Germany)

    1998-12-31

    In contrast to internal oxidation, sulfidation and carburization, very little information is available regarding internal chlorination, especially diffusion of chlorine in metallic alloys. This paper describes results of experiments on Ni-Cr alloys (<10 wt% Cr) exposed in an atmosphere containing radioactive HCl. The diffusion of chlorine in the alloy can be determined by measurement of residual {beta}-activity from the sample surface. Successively thin layers (0.5-10 {mu}m) of the alloy were removed by lapping and the surface activity was measured to obtain a depth profile. Both single and polycrystalline materials were tested. Through this work it should be determined if there is in fact solubility and diffusion of chlorine in Ni-based alloys as some authors have proposed or if the ingress of chlorine is mainly a grain boundary phenomenon. (orig.)

  8. Rapidly solidified ferromagnetic shape memory alloys

    Science.gov (United States)

    Craciunescu, C. M.; Ercuta, A.; Mitelea, I.; Valeanu, M.; Teodorescu, V. S.; Lupu, N.; Chiriac, H.

    2008-05-01

    Ferromagnetic shape memory alloys have been manufactured by various techniques involving rapid solidification. Bulk alloys have been obtained by extracting the melted alloy in especially designed copper molds; glass coated wires have been obtained by drawing the melt from glass recipients followed by water cooling and ribbons have been fabricated by melt-spinning. Microstructural observations show particular solidification aspects of fractured areas, while ferromagnetic behavior has been detected in glass coated wires obtained by rapid solidification. The martensitic microstructure was observed on Co-Ni-Ga rapid solidified bulk alloys and Fe-Pd ribbons. The memory effect was detected using a Vibran system that allows the detection of the phase transition for the ribbons and by visual observation for other specimens. The conclusions of the observations are related to the comparison between the ferromagnetic behaviors of shape memory alloys solidified using different techniques.

  9. Long - range foundry Al composite alloys

    Directory of Open Access Journals (Sweden)

    A. D. Mekhtiev

    2014-10-01

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

  10. Concepts in surface alloying of metals

    Directory of Open Access Journals (Sweden)

    Santosh S. Hosmani

    2013-03-01

    Full Text Available Surface alloying is widely used method in industries to improve the surface properties of metals/alloys. Significance of the various surface engineering techniques to improve the properties of engineering components in various applications, for example, automobile industries, has grown substantially over the many years. The current paper is focused on the fundamental scientific aspects of the surface alloying of metals. Widely used surface alloying elements involved are interstitial elements such as nitrogen, carbon, and substitutional element, chromium. This topic is interdisciplinary in nature and various science and engineering streams can work together for the further development in this topic. This paper has attempted to cover the essential concepts of surface alloying along with some of the interesting results in this research area.

  11. Superior hydrogen storage in high entropy alloys

    Science.gov (United States)

    Sahlberg, Martin; Karlsson, Dennis; Zlotea, Claudia; Jansson, Ulf

    2016-11-01

    Metal hydrides (MHx) provide a promising solution for the requirement to store large amounts of hydrogen in a future hydrogen-based energy system. This requires the design of alloys which allow for a very high H/M ratio. Transition metal hydrides typically have a maximum H/M ratio of 2 and higher ratios can only be obtained in alloys based on rare-earth elements. In this study we demonstrate, for the first time to the best of our knowledge, that a high entropy alloy of TiVZrNbHf can absorb much higher amounts of hydrogen than its constituents and reach an H/M ratio of 2.5. We propose that the large hydrogen-storage capacity is due to the lattice strain in the alloy that makes it favourable to absorb hydrogen in both tetrahedral and octahedral interstitial sites. This observation suggests that high entropy alloys have future potential for use as hydrogen storage materials.

  12. Interdisciplinaridade nos Estudos de Tradução

    Directory of Open Access Journals (Sweden)

    José Lambert

    2017-05-01

    Full Text Available http://dx.doi.org/10.5007/2175-7968.2017v37n2p246 Desde 1992 (Snell-Hornby et al. 1994 os Estudos de Tradução* (doravante EdT reivindicaram o estatuto de  “interdisciplina”.  Aliás, ainda há dúvidas sobre seu estatuto acadêmico que é mais recente em relação à profissão. Desde Holmes 1988 [1972], o desenvolvimento dos EdT foi, várias vezes, considerado uma história de sucesso; embora não se saiba claramente se os resultados acadêmicos (argumentos e componentes peculiares vinculados ao seu prestígio, tais como livros, sociedades, estudiosos reconhecidos, congressos, foram mais decisivos do que o mercado da tradução no progressivo reconhecimento dos EdT.

  13. estudo numa população do Grande Porto

    OpenAIRE

    Baptista, Diogo de Sousa

    2014-01-01

    Projeto de Pós-Graduação/Dissertação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Ciências Farmacêuticas A Hipersensibilidade Dentinária é uma temática fundamental na saúde oral da atualidade. No presente estudo faz-se uma reflexão sobre a perceção da população adulta acerca da Hipersensibilidade Dentinária, condição geral de saúde da amostra, hábitos parafuncionais, parâmetros com variação, prevalência, hábitos de higiene oral ...

  14. Estudos Africanos em Portugal e Espanha: perspectivas comparadas

    OpenAIRE

    Heimer, Franz-Wilhelm; Tomàs, Jordi

    2010-01-01

    Desde meados do século XX, a acompanhar o processo de descolonização e as trajectórias pós-coloniais em África, constituiu-se a nível internacional uma nova área do saber, a dos estudos africanos interdisciplinares em ciências sociais (no sentido amplo, incluindo a economia e a história). Retomando e transformando algumas vezes tradições anteriores, fundou-se mundo afora neste domínio uma larga centena de instituições científicas, de investigação e de ensino. Criaram-se, na Europa Ocidental e...

  15. Planeamento de uma estrada utilizando CCS Candy - Caso de estudo

    OpenAIRE

    Oliveira, Sara Maria de

    2013-01-01

    O tema desta dissertação foi escolhido tendo em consideração a crescente necessidade de planeamento de empreitadas de construção de estradas, sendo um dos objetivos desta dissertação o de oferecer uma visão global do processo de planeamento da construção de uma estrada, focado apenas no fator tempo, recorrendo a ferramentas informáticas e utilizando um caso de estudo de uma estrada real e já construída. Inicialmente, faz-se uma breve descrição dos métodos de planeamento mais aplicados em p...

  16. Estudos sobre a paz e cultura da paz

    OpenAIRE

    Pureza, José Manuel

    2000-01-01

    Segundo o autor, a cultura da paz implica uma mudança quer na forma como a “alta cultura” lida com a realidade quer no tipo de abordagem que o senso comum faz às relações sociais, sendo que a ruptura com a ideologia conservadora, ou seja, com o senso comum realista só é possível graças a estas alterações. O autor realça tanto a importância que os estudos sobre a paz têm para o surgimento de um conceito amplo de paz, desenvolvido por Johan Galtung, como o facto destes esta...

  17. COMPORTAMENTO DE CONSUMO ECOLOGICAMENTE CONSCIENTE: ESTUDO COMPARATIVO BRASIL X CHINA

    Directory of Open Access Journals (Sweden)

    Tatiana Azevedo Yeh

    2015-12-01

    Full Text Available Esse estudo buscou identificar os fatores que afetam o comportamento de consumo ecologicamente consciente (CCEC. Foram utilizadas duas amostras, uma com chineses e outra com brasileiros. Para análise dos dados utilizou-se técnica estatística descritiva, Teste t e regressão linear multivariada. Demonstrou-se, nas duas amostras, dois construtos comumente significativos para o CCEC: o próprio comportamento verde em si para realização de outros CCEC e os moderadores externos. Identificou-se que a baixa disponibilidade de produtos verdes entre os brasileiros é barreira à ser considerada para o fomento do CCEC no Brasil, que encontra-se na primeira fase de comportamento verde que é a compra. E que os chineses realizam todos os tipos de comportamento: compra, uso e reciclagem.

  18. Superconductivity in Metals and Alloys

    Science.gov (United States)

    1963-02-01

    sintered material (Reed, Gatos , LaFleur, and Roddy, 1962). It has great importance for any materials work, since generalizations based only on stoichio...1961),Phys. Rev. Letters 6, 597. Goodman, B. B., (1962) IBM J. Research and Development 6, 63. Gor’kov, L. P., (1960), Soy . Phys. JETP 10, 998...34Superconductivity in Metals and Alloys-Technical Documentary Report No. ASD-TDR-62-269, Contract No. AF 33(616)-640 5. Reed, T. B., Gatos , H. C., LaFleur, W. j

  19. REVIEW ON RESEARCH AND DEVELOPMENT OF MAGNESIUM ALLOYS

    Institute of Scientific and Technical Information of China (English)

    Z.Yaug; J.P.Li; J.X.Zhang; G.W.Lorimer; J.Robson

    2008-01-01

    The current research and development of magnesium alloys is summarized. Several aspects of magnesium alloys are described: cast Mg alloy, wrought Mg alloy, and novel processing. The subjects are discussed individually and recommendations for further study arc listed in the final section.

  20. Phase transformations during sintering of mechanically alloyed TiPt

    CSIR Research Space (South Africa)

    Nxumalo, S

    2010-10-01

    Full Text Available A TiPt alloy was produced by mechanically alloying the desired quantities of titanium and platinum. The resultant TiPt alloy powder was cold pressed to produce green bodies. Several sintering conditions were used to sinter this alloy...

  1. Process Simulation and Modeling for Advanced Intermetallic Alloys.

    Science.gov (United States)

    1994-06-01

    34Microstructure-Property Correlation in TiAl-Base Alloys", in Microstructure/ Proverty Relationships in Titanium Aluminides and Alloys eds. Y-W. Kim and...Gamma Titanium Aluminide Alloy", in Microstructure/ Proverty Relationships in Titanium Aluminides and Alloys eds. Y-W. Kim and R.R. Boyer, The

  2. (Sem saber e (com poder nos estudos organizacionais

    Directory of Open Access Journals (Sweden)

    José Henrique de Faria

    Full Text Available Bacon afirma que saber é poder. Tragtenberg contesta. Essa discussão, na contemporaneidade, faz-se mais importante do que se possa imaginar. Por isso, o objetivo central deste artigo é verificar as relações entre saber e poder, na atualidade, levando em consideração o papel da ciência e dos elementos imediatos a ela relacionados. Quanto aos objetivos específicos deste estudo, destacam-se: · compreender o sentido da filosofia e da ciência e suas relações com a ideologia; · verificar como o discurso da neutralidade axiológica da ciência se apresenta como mito da modernidade e como se dá a presença da "fé" na filosofia e na ciência, na contemporaneidade; · refletir sobre a consolidação da ciência como força produtiva e/ou como mercadoria no atual sistema econômico; · destacar a importância do complexo industrial militar como financiador de grande parte dos atuais estudos científicos; · entender o processo de racionalização, avaliando a importância do pragmatismo e da burocracia universitária como afirmação da ciência na atualidade. O texto conclui que tanto é possível a existência de saber como poder (Bacon como a de não saber, mas com poder (Tragtenberg para compreendermos a relação entre saber e poder.

  3. O Zulliger no sistema compreensivo: um estudo de fidedignidade

    Directory of Open Access Journals (Sweden)

    Anna Elisa de Villemor-Amaral

    Full Text Available Os testes psicológicos têm passado por verificações criteriosas de validade e precisão a fim de atender às exigências éticas e científicas. O objetivo desta pesquisa foi averiguar a precisão do Teste Zulliger no sistema compreensivo por meio do teste-reteste. Participaram do estudo 25 sujeitos, do sexo masculino, não pacientes, estudantes de teologia do interior de São Paulo. Utilizou-se um questionário para dados socioeconômico-familiar e o Zulliger. A aplicação dos instrumentos foi individual, durando cerca de 40 minutos, com intervalo de 5 meses entre teste-reteste. Dos protocolos, 25% foram recodificados por um juiz às cegas, obtendo-se índices satisfatórios de precisão. Foram selecionados 16 indicadores para se realizar as estatísticas descritivas e estudos de correlação com método de Pearson. Desses, dez alcançaram índices de precisão satisfatórios, entre 0,60-0,99; quatro tiveram uma precisão entre 0,40-0,60, todos com nível de significância entre 0,01 e 0,05. Os resultados foram satisfatórios e contribuíram para demonstrar a precisão do instrumento.

  4. Estudos cronotópicos em narrativas audiovisuais

    Directory of Open Access Journals (Sweden)

    Egle Müller Spinelli

    2008-11-01

    Full Text Available O presente trabalho pretende aplicar o conceito de cronotopia de Bakhtin à análise de narrativas audiovisuais. Para tanto, será discutido o conceito de cronotopo bakhtiniano e sua relação com os estudos de Saussure, com o intuito de mostrar como os elementos cronotópicos podem estar ligados a contextos que vão além do enunciado, remetendo a mecanismos da enunciação. No estudo são analisados filmes que apresentam determinadas características semelhantes às dos principais tipos de cronotopia estabelecidos por Bakhtin: a da aventura, a do cotidiano e a autobiográfica, respectivamente correspondentes aos filmes Corra Lola, Corra (Tom Tykwer, 1998, Boca de Ouro (Nelson Pereira dos Santos, 1962 e Rashomon (Akira Kurosawa, 1950. Palavras-chave: cronotopia; enunciação; cinema; Bakhtin Abstract Chronotopic studies in audiovisual narratives - This paper proposes to apply Bakhtin's concept of chronotopia in an analysis of audiovisual discourse. To this end, it discusses the Bakhtin's postulation of the chronotope and its relation with the studies of Saussure in order to show how chronotopic elements may be connected to contexts that go beyond simple statements, suggesting mechanisms of enunciation. The films Run Lola, Run (Tom Tykwer, 1998, Boca de Ouro (Nelson Pereira dos Santos, 1962 and Rashomon (Akira Kurosawa, 1950 are used here to illustrate the principal chronotopic types established by Bakhtin, namely, adventure, everyday life and autobiography. Key words: chronotope; enunciation; cinema; Bakhtin

  5. O Zulliger no sistema compreensivo: um estudo de fidedignidade

    Directory of Open Access Journals (Sweden)

    Anna Elisa de Villemor-Amaral

    Full Text Available Os testes psicológicos têm passado por verificações criteriosas de validade e precisão a fim de atender às exigências éticas e científicas. O objetivo desta pesquisa foi averiguar a precisão do Teste Zulliger no sistema compreensivo por meio do teste-reteste. Participaram do estudo 25 sujeitos, do sexo masculino, não pacientes, estudantes de teologia do interior de São Paulo. Utilizou-se um questionário para dados socioeconômico-familiar e o Zulliger. A aplicação dos instrumentos foi individual, durando cerca de 40 minutos, com intervalo de 5 meses entre teste-reteste. Dos protocolos, 25% foram recodificados por um juiz às cegas, obtendo-se índices satisfatórios de precisão. Foram selecionados 16 indicadores para se realizar as estatísticas descritivas e estudos de correlação com método de Pearson. Desses, dez alcançaram índices de precisão satisfatórios, entre 0,60-0,99; quatro tiveram uma precisão entre 0,40-0,60, todos com nível de significância entre 0,01 e 0,05. Os resultados foram satisfatórios e contribuíram para demonstrar a precisão do instrumento.

  6. Estudo sobre reciclagem de lâmpadas fluorescentes

    Directory of Open Access Journals (Sweden)

    Danniele Miranda Bacila

    2014-01-01

    Full Text Available Lâmpadas fluorescentes (LF contêm mercúrio em sua composição, um metal pesado que pode causar danos à saúde e ao meio ambiente. As LF são amplamente consumidas no Brasil, porém o descarte correto de LF usadas não é amplamente divulgado e os índices de reciclagem são baixos. O objetivo deste estudo foi demonstrar a relevância do descarte adequado, avaliar as tecnologias de reciclagem e a destinação dos materiais, por meio de estudo comparativo entre Brasil e Alemanha. Através de visitas a recicladoras e análise das tecnologias adotadas nos dois países, foi verificado que no Brasil o vidro é destinado à indústria de cerâmica, enquanto que na Alemanha é destinado à fabricação de tubos para LF. Além disso, foi observado que o mercúrio apresenta diversas possibilidades de uso. Um ponto a ser explorado nos dois países, e de grande potencial para reciclagem, é a recuperação de terras raras do pó fosfórico presente nas LF. Tanto Brasil como Alemanha possuem oportunidades de melhoria na logística reversa de LF, por meio da qual se torna possível elevar os índices de reciclagem e reduzir os impactos ambientais causados pelo descarte inadequado de LF usadas.

  7. Alloy hardening and softening in binary molybdenum alloys as related to electron concentration.

    Science.gov (United States)

    Stephens, J. R.; Witzke, W. R.

    1972-01-01

    Determination of the effects of alloy additions of Hf, Ta, W, Re, Os, Ir, and Pt on the hardness of Mo. Special emphasis was placed on alloy softening in these binary Mo alloys. A modified microhardness test unit permitted hardness determinations at homologous temperatures ranging from 0.02 to 0.15, where alloy softening normally occurs in bcc alloys. Results showed that alloy softening was produced by those elements having an excess of s + d electrons compared to Mo while those elements having an equal number or fewer s + d electrons than Mo failed to produce alloy softening. The magnitude of the softening and the amount of solute element at the hardness minimum diminished rapidly with increasing test temperature. At solute concentrations where alloy softening was observed, the temperature sensitivity of hardness was lowered. For solute elements having an excess of s + d electrons or fewer s + d electrons than Mo, alloy softening and alloy hardening can be correlated with the difference in number of s + d electrons of the solute element and Mo.

  8. Nucleation promotion of Sn-Ag-Cu lead-free solder alloys via micro alloying

    Science.gov (United States)

    Mao, Jie

    Sn-Ag-Cu (SAC) alloy system is widely accepted as a viable Pb-free alternative to Sn-Pb alloys for microelectronics packaging applications. Compared with its Pb-containing predecessor SAC alloys tend to have coarse grain structure, which is believed to be caused by high undercooling prior to nucleation. This work explores the possibility of modifying the nucleation process and reducing the undercooling of SAC alloys via introducing minor alloying elements. The mechanisms through which effective alloying elements influenced the nucleation process of SAC alloys are investigated with microstructural and chemical analyses. Minor alloying elements (Mn and Zn) are found promoting beta-Sn nucleation and reducing the undercooling of SAC. Manganese promotes beta-Sn primary phase nucleation through the formation of MnSn2 intermetallic compound. Experimental results in this work support the claim by previous researchers that zinc promotes beta-Sn primary phase nucleation through the formation of zinc oxide. In addition to nucleation, this work also assesses the microstructural impact of minor elements on Sn-Ag-Cu based alloys. Methods have been developed to quantify and compare microstructural impacts of minor elements and efficiently study their partitioning behaviors. LA-ICPMS was introduced to SAC alloy application to efficiently study partitioning behaviors of minor elements.

  9. NiAl alloys for structural uses

    Science.gov (United States)

    Koss, D. A.

    1991-01-01

    Alloys based on the intermetallic compound NiAl are of technological interest as high temperature structural alloys. These alloys possess a relatively low density, high melting temperature, good thermal conductivity, and (usually) good oxidation resistance. However, NiAl and NiAl-base alloys suffer from poor fracture resistance at low temperatures as well as inadequate creep strength at elevated temperatures. This research program explored macroalloying additions to NiAl-base alloys in order to identify possible alloying and processing routes which promote both low temperature fracture toughness and high temperature strength. Initial results from the study examined the additions of Fe, Co, and Hf on the microstructure, deformation, and fracture resistance of NiAl-based alloys. Of significance were the observations that the presence of the gamma-prime phase, based on Ni3Al, could enhance the fracture resistance if the gamma-prime were present as a continuous grain boundary film or 'necklace'; and the Ni-35Al-20Fe alloy was ductile in ribbon form despite a microstructure consisting solely of the B2 beta phase based on NiAl. The ductility inherent in the Ni-35Al-20Fe alloy was explored further in subsequent studies. Those results confirm the presence of ductility in the Ni-35Al-20Fe alloy after rapid cooling from 750 - 1000 C. However exposure at 550 C caused embrittlement; this was associated with an age-hardening reaction caused by the formation of Fe-rich precipitates. In contrast, to the Ni-35Al-20Fe alloy, exploratory research indicated that compositions in the range of Ni-35Al-12Fe retain the ordered B2 structure of NiAl, are ductile, and do not age-harden or embrittle after thermal exposure. Thus, our recent efforts have focused on the behavior of the Ni-35Al-12Fe alloy. A second parallel effort initiated in this program was to use an alternate processing technique, mechanical alloying, to improve the properties of NiAl-alloys. Mechanical alloying in the

  10. Photonic crystal digital alloys and their band structure properties.

    Science.gov (United States)

    Lee, Jeongkug; Kim, Dong-Uk; Jeon, Heonsu

    2011-09-26

    We investigated semi-disordered photonic crystals (PCs), digital alloys, and made thorough comparisons with their counterparts, random alloys. A set of diamond lattice PC digital alloys operating in a microwave regime were prepared by alternately stacking two kinds of sub-PC systems composed of alumina and silica spheres of the same size. Measured transmission spectra as well as calculated band structures revealed that when the digital alloy period is short, band-gaps of the digital alloys are practically the same as those of the random alloys. This study indicates that the concept of digital alloys holds for photons in PCs as well.

  11. An Alternate to Cobalt-Base Hardfacing Alloys

    Science.gov (United States)

    Hickl, Anthony J.

    1980-03-01

    The price of cobalt has risen dramatically in the last few years, and supply has often been uncertain. The most popular hardfacing alloys contain substantial amounts of cobalt, and have thus been especially affected by these factors. The present study has developed a new hardfacing alloy, HAYNES Alloy No. 716, with lower cobalt content, to replace the most popular alloy, HAYNES STELLITE Alloy No. 6 which is cobalt based. The alloy design which led to the development of the new alloy is discussed, and properties are compared with Alloy No. 6. Hardness at room temperature and elevated temperatures, weldability, and corrosion and abrasion resistance of the new alloy compare favorably with Alloy No. 6.

  12. Environmentally Assisted Cracking of Nickel Alloys - A Review

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, R

    2004-07-12

    Nickel can dissolve a large amount of alloying elements while still maintaining its austenitic structure. That is, nickel based alloys can be tailored for specific applications. The family of nickel alloys is large, from high temperature alloys (HTA) to corrosion resistant alloys (CRA). In general, CRA are less susceptible to environmentally assisted cracking (EAC) than stainless steels. The environments where nickel alloys suffer EAC are limited and generally avoidable by design. These environments include wet hydrofluoric acid and hot concentrated alkalis. Not all nickel alloys are equally susceptible to cracking in these environments. For example, commercially pure nickel is less susceptible to EAC in hot concentrated alkalis than nickel alloyed with chromium (Cr) and molybdenum (Mo). The susceptibility of nickel alloys to EAC is discussed by family of alloys.

  13. Density and Structure Analysis of Molten Ni-W Alloys

    Institute of Scientific and Technical Information of China (English)

    Feng XIAO; Liang FANG

    2004-01-01

    Density of molten Ni and Ni-W alloys was measured in the temperature range of 1773~1873 K with a sessile drop method.The density of molten Ni and Ni-W alloys trends to decrease with increasing temperature. The density and molar volume of the alloys trend to increase with increasing W concentration in the alloys. The calculation result shows an ideal mixing of Ni-W alloys.

  14. Indium Helps Strengthen Al/Cu/Li Alloy

    Science.gov (United States)

    Blackburn, Linda B.; Starke, Edgar A., Jr.

    1992-01-01

    Experiments on Al/Cu/Li alloys focus specifically on strengthening effects of minor additions of In and Cd. Indium-bearing alloy combines low density with ability to achieve high strength through heat treatment alone. Tensile tests on peak-aged specimens indicated that alloy achieved yield strength approximately 15 percent higher than baseline alloy. Alloy highly suitable for processing to produce parts of nearly net shape, with particular applications in aircraft and aerospace vehicles.

  15. Thermal aging effects in refractory metal alloys

    Science.gov (United States)

    Stephens, Joseph R.

    1987-01-01

    The alloys of niobium and tantalum are attractive from a strength and compatibility viewpoint for high operating temperatures required in materials for fuel cladding, liquid metal transfer, and heat pipe applications in space power systems that will supply from 100 kWe to multi-megawatts for advanced space systems. To meet the system requirements, operating temperatures ranging from 1100 to 1600 K have been proposed. Expected lives of these space power systems are from 7 to 10 yr. A program is conducted at NASA Lewis to determine the effects of long-term, high-temperature exposure on the microstructural stability of several commercial tantalum and niobium alloys. Variables studied in the investigation include alloy composition, pre-age annealing temperature, aging time, temperature, and environment (lithium or vacuum), welding, and hydrogen doping. Alloys are investigated by means of cryogenic bend tests and tensile tests. Results show that the combination of tungsten and hafnium or zirconium found in commercial alloys such as T-111 and Cb-752 can lead to aging embrittlement and increased susceptibility to hydrogen embrittlement of ternary and more complex alloys. Modification of alloy composition helps to eliminate the embrittlement problem.

  16. Aeronautical requirements for Inconel 718 alloy

    Science.gov (United States)

    Elefterie, C. F.; Guragata, C.; Bran, D.; Ghiban, B.

    2017-06-01

    The project goal is to present the requirements imposed by aviation components made from super alloys based on Nickel. A significant portion of fasteners, locking lugs, blade retainers and inserts are manufactured from Alloy 718. The thesis describes environmental factors (corrosion), conditions of external aggression (salt air, intense heat, heavy industrial pollution, high condensation, high pressure), mechanical characteristics (tensile strength, yield strength and fatigue resistance) and loadings (tensions, compression loads) that must be satisfied simultaneously by Ni-based super alloy, compared to other classes of aviation alloys (as egg. Titanium alloys, Aluminum alloys). For this alloy the requirements are strength durability, damage tolerance, fail safety and so on. The corrosion can be an issue, but the fatigue under high-magnitude cyclic tensile loading it’s what limits the lifetime of the airframe. Also, the excellent malleability and weldability characteristics of the 718 system make the material physical properties tolerant of manufacturing processes. These characteristics additionally continue to provide new opportunities for advanced manufacturing methods.

  17. Surface modification of Ti alloy by electro-explosive alloying and electron-beam treatment

    Energy Technology Data Exchange (ETDEWEB)

    Gromov, Victor, E-mail: gromov@physics.sibsiu.ru; Kobzareva, Tatiana, E-mail: kobzarevatanya@mail.ru; Budovskikh, Evgeniy, E-mail: budovskih-ea@physics.sibsiu.ru; Baschenko, Lyudmila, E-mail: gromov@physics.sibsiu.ru [Siberian State Industrial University, 42, Kirov Str., Novokuznetsk, 654007 (Russian Federation); Ivanov, Yuryi, E-mail: yufi55@mail.ru [Institute of High Current Electronics SB RAS, 4, Akademicheskii Av. Tomsk, 634055 (Russian Federation); National Research Tomsk State University, 30, Lenina Av. Tomsk, 634034 (Russian Federation)

    2016-01-15

    By methods of modern physical metallurgy the analysis of structure phase states of titanium alloy VT6 is carried out after electric explosion alloying with boron carbide and subsequent irradiation by pulsed electron beam. The formation of an electro-explosive alloying zone of a thickness up to 50 µm, having a gradient structure, characterized by decrease in the concentration of carbon and boron with increasing distance to the treatable surface has been revealed. Subsequent electron-beam treatment of alloying zone leads to smoothing of the alloying area surface and is accompanied by the multilayer structure formation at the depth of 30 µm with alternating layers with different alloying degrees having the structure of submicro - and nanoscale level.

  18. Surface modification of Ti alloy by electro-explosive alloying and electron-beam treatment

    Science.gov (United States)

    Gromov, Victor; Kobzareva, Tatiana; Ivanov, Yuryi; Budovskikh, Evgeniy; Baschenko, Lyudmila

    2016-01-01

    By methods of modern physical metallurgy the analysis of structure phase states of titanium alloy VT6 is carried out after electric explosion alloying with boron carbide and subsequent irradiation by pulsed electron beam. The formation of an electro-explosive alloying zone of a thickness up to 50 µm, having a gradient structure, characterized by decrease in the concentration of carbon and boron with increasing distance to the treatable surface has been revealed. Subsequent electron-beam treatment of alloying zone leads to smoothing of the alloying area surface and is accompanied by the multilayer structure formation at the depth of 30 µm with alternating layers with different alloying degrees having the structure of submicro - and nanoscale level.

  19. Preparation of casting alloy ZL101 with coarse aluminum-silicon alloy

    Institute of Scientific and Technical Information of China (English)

    YOU Jing; WANG Yao-wu; FENG Nai-xiang; YANG Ming-sheng

    2008-01-01

    The coarse Al-Si alloy produced by carbothermal reduction of aluminous ore contains 55% Al, 25% Si and some impurities. The main impurities are slag and iron. The process of manufacturing casting Al-Si alloy ZL101 with the coarse Al-Si alloy was studied. The phase constitution and microstructure of the coarse Al-Si alloy, slag and ZL101 were examined by X-ray diffractometry and scanning electron microscopy. The results show that the content of silicon and iron in the casting alloy reduces with the increase of the dosage of purificant and manganese, but increases with the rise of filtering temperature. It is found that casting Al-Si alloy conforming to industrial standard can be produced after refining by using purificant, and removing iron by using manganese and added magnesium.

  20. Fabrication of high strength conductivity submicroncrystalline Cu-5 % Cr alloy by mechanical alloying

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Cu-5%Cr alloy bulk material with submicron grains were fabricated by mechanical alloying and subsequanthot hydrostatic extruaion. The micrestructure, mechanical properties and electrical conductivity of the alloy were experimentally investigated, and the influence of the extrusion temperature on its microstructure and properties was made clear.Also, the strengthening mechanism of the alloy was diacussed. It was revealed that the microstructure of the alloy is veryfine, with an average grain size being about 100 ~ 120nm, and thus possesses significant fine-grain strengthening effect,leading to very high mechanical strength of 800 ~ 1 000 MPa. Meanwhile, the alloy also possesses quite good electricalconductivity and moderate tensile elongation, with the former in the range of 55% ~ 70%(IACS) and the latter about5 % respectively.

  1. Development of environmentally friendly cast alloys and composites. High zinc Al-base cast alloys

    Directory of Open Access Journals (Sweden)

    W.K. Krajewski

    2010-01-01

    Full Text Available This work is devoted to grain refinement of the foundry Al-20 wt% Zn (AlZn20 alloy, aiming at improving ductility of the sand-cast alloy The melted alloy was inoculated using traditional AlTi5B1 (TiBAl and AlTi3C0.15 (TiCAl master alloys and newly introduced (Zn,Al-Ti3 one. The performed structural examinations showed out significant increasing of the grain population of the inoculated alloy and plas-ticity increase represented by elongation. The high damping properties of the initial alloy, measured using an ultrasonic Olympus Epoch XT device, are basicly preserved after inoculation. Also tensile strength preserves its good values, while elongation shows an increase – which are beneficials of the employed grain-refining process.

  2. Alloying element's substitution in titanium alloy with improved oxidation resistance and enhanced magnetic properties

    Science.gov (United States)

    Yu, Ang-Yang; Wei, Hua; Hu, Qing-Miao; Yang, Rui

    2017-01-01

    First-principles method is used to characterize segregation and magnetic properties of alloyed Ti/TiO2interface. We calculate the segregation energy of the doped Ti/TiO2 interface to investigate alloying atom's distribution. The oxidation resistance of Ti/TiO2 interface is enhanced by elements Fe and Ni but reduced by element Co. Magnetism could be produced by alloying elements such as Co, Fe and Ni in the bulk of titanium and the surface of Ti at Ti/TiO2 interface. The presence of these alloying elements could transform the non-magnetic titanium alloys into magnetic systems. We have also calculated the temperature dependence of magnetic permeability for the doped and pure Ti/TiO2 interfaces. Alloying effects on the Curie temperature of the Ti/TiO2 interface have been elaborated.

  3. Effects of alloying side B on Ti-based AB2 hydrogen storage alloys

    Institute of Scientific and Technical Information of China (English)

    王家淳; 于荣海; 刘庆

    2004-01-01

    Ti-based AB2-type hydrogen storage alloys are a group of promising materials, which will probably replace the prevalent rare earth-based AB5-type alloys and be adopted as the main cathode materials of nickelmetal hydride (Ni-MH) batteries in the near future. Alloying in side B is a major way to improve the performance of Ti-based AB2-type alloys. Based on recent studies, the effects of alloying elements in side B upon the performance of Ti-based AB2 -type hydrogen storage alloys are systematically reviewed here. These performances are divided into two categories, namely PCI characteristics, including hydrogen storage capacity (HSC), plateau pressure (PP), pressure hysteresis (PH) and pressure plateau sloping (PPS) , and electrochemical properties, including discharge capacity (DC), activation property (AP), cycling stability (CS) and high-rate dischargeability (HRD). Furthermore, the existing problems in these investigations and some suggestions for future research are proposed.

  4. Fatigue Characteristics of Selected Light Metal Alloys

    Directory of Open Access Journals (Sweden)

    Cieśla M.

    2016-03-01

    Full Text Available The paper addresses results of fatigue testing of light metal alloys used in the automotive as well as aerospace and aviation industries, among others. The material subject to testing comprised hot-worked rods made of the AZ31 alloy, the Ti-6Al-4V two-phase titanium alloy and the 2017A (T451 aluminium alloy. Both low- and high-cycle fatigue tests were conducted at room temperature on the cycle asymmetry ratio of R=-1. The low-cycle fatigue tests were performed using the MTS-810 machine on two levels of total strain, i.e.Δεc= 1.0% and 1.2%. The high-cycle fatigue tests, on the other hand, were performed using a machine from VEB Werkstoffprufmaschinen-Leipzig under conditions of rotary bending. Based on the results thus obtained, one could develop fatigue life characteristics of the materials examined (expressed as the number of cycles until failure of sample Nf as well as characteristics of cyclic material strain σa=f(N under the conditions of low-cycle fatigue testing. The Ti-6Al-4V titanium alloy was found to be characterised by the highest value of fatigue life Nf, both in lowand high-cycle tests. The lowest fatigue life, on the other hand, was established for the aluminium alloys examined. Under the high-cycle fatigue tests, the life of the 2017A aluminium and the AZ31 magnesium alloy studied was determined by the value of stress amplitude σa. With the stress exceeding 150 MPa, it was the aluminium alloy which displayed higher fatigue life, whereas the magnesium alloy proved better on lower stress.

  5. Electroplated solder alloys for flip chip interconnections

    Science.gov (United States)

    Annala, P.; Kaitila, J.; Salonen, J.

    1997-01-01

    Flip chip mounting of bare dice is gaining widespread use in microelectronics packaging. The main drivers for this technology are high packaging density, improved performance at high frequency, low parasitic effects and potentially high reliability and low cost. Many companies have made significant efforts to develop a technology for bump processing, bare die testing and underfill encapsulation to gain the benefit of all potential advantages. We have focussed on low cost bumping of fully processed silicon wafers to develop a flexible scheme for various reflow requirements. The bumping process is based on galvanic plating from an alloy solution or, alternatively, from several elemental plating baths. Sputtered Mo/Cu or Cr/Cu is used as a wettable base for electroplating. Excess base metal is removed by using the bumps as an etching mask. Variation of the alloy composition or the layer structure, allows the adjustment of the bump reflow temperature for the specific requirements of the assembly. Using binary tin-lead and ternary tin-lead-bismuth alloys, reflow temperatures from 100 °C (bismuth rich alloys) to above 300 °C (lead rich alloys) can be covered. The influence of the plating current density on the final alloy composition has been established by ion beam analysis of the plated layers and a series of reflow experiments. To control the plating uniformity and the alloy composition, a new cup plating system has been built with a random flow pattern and continuous adjustment of the current density. A well-controlled reflow of the bumps has been achieved in hot glycerol up to the eutectic point of tin-lead alloys. For high temperature alloys, high molecular weight organic liquids have been used. A tensile pull strength of 20 g per bump and resistance of 5 mΩ per bump have been measured for typical eutectic tin-lead bumps of 100 μm in diameter.

  6. Influence of the selected alloy additions on limiting the phase formation in Cu-Zn alloys

    Directory of Open Access Journals (Sweden)

    J. Kozana

    2010-01-01

    Full Text Available Influence of the selected alloy additions into copper and zinc alloys was investigated in order to find out the possibility of limiting the precipitation of unfavourable phase . The observation of microstructures and strength tests were performed. The results of metallographic and strength investigations indicate positive influence of small amounts of nickel, cobalt or tellurium. The precise determination of the influence of the selected alloy additions on limiting the gamma phase formation will be the subject of further examinations.

  7. Comparison of Lost Foam Casting of AM60B Alloy and A356 Alloy

    Energy Technology Data Exchange (ETDEWEB)

    Han, Qingyou [ORNL; Dinwiddie, Ralph Barton [ORNL; Sklad, Philip S [ORNL; Currie, Kenneth [Tennessee Technological University; Vondra, Fred [Tennessee Technological University; Abdelrahman, Mohamed [Tennessee Technological University; Walford, Graham [Walford Technologies; Nolan, Dennis J [Foseco-Morval; Nedkova, Teodora [Kaiser Aluminum

    2007-01-01

    The article describes the research activities at Oak Ridge National Laboratory and Tennessee Technological University on lost foam casting of magnesium alloys. The work was focused on castings of simple geometries such as plate castings and window castings in order to compare the difference in castability between magnesium alloys and aluminum alloy using the lost foam casting process. Significant differences between lost foam aluminum casting and lost foam magnesium casting have been observed.

  8. Combustion synthesis of bulk nanocrystalline iron alloys

    OpenAIRE

    Licai Fu; Jun Yang; Weimin Liu

    2016-01-01

    The controlled synthesis of large-scale nanocrystalline metals and alloys with predefined architecture is in general a big challenge, and making full use of these materials in applications still requires greatly effort. The combustion synthesis technique has been successfully extended to prepare large-scale nanocrystalline metals and alloys, especially iron alloy, such as FeC, FeNi, FeCu, FeSi, FeB, FeAl, FeSiAl, FeSiB, and the microstructure can be designed. In this issue, recent progress on...

  9. Graded coatings for metallic implant alloys

    Energy Technology Data Exchange (ETDEWEB)

    Saiz, Eduardo; Tomsia, Antoni P.; Fujino, Shigeru; Gomez-Vega, Jose M.

    2002-08-01

    Graded glass and glass-hydroxyapatite coatings on Ti-based and Co-Cr alloys have been prepared using a simple enameling technique. The composition of the glasses has been tailored to match the thermal expansion of the alloys. By controlling the firing time, and temperature, it has been possible to control the reactivity between the glass and the alloy and to fabricate coatings (25 to 150 mu m thick) with excellent adhesion to the substrate, resistant to corrosion and able to precipitate hydroxyapatite during in vitro tests in simulated body fluid.

  10. Stress corrosion cracking of titanium alloys

    Science.gov (United States)

    Statler, G. R.; Spretnak, J. W.; Beck, F. H.; Fontana, M. G.

    1974-01-01

    The effect of hydrogen on the properties of metals, including titanium and its alloys, was investigated. The basic theories of stress corrosion of titanium alloys are reviewed along with the literature concerned with the effect of absorbed hydrogen on the mechanical properties of metals. Finally, the basic modes of metal fracture and their importance to this study is considered. The experimental work was designed to determine the effects of hydrogen concentration on the critical strain at which plastic instability along pure shear directions occurs. The materials used were titanium alloys Ti-8Al-lMo-lV and Ti-5Al-2.5Sn.

  11. Thermodynamics and Structure of Plutonium Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Allen, P G; Turchi, P A; Gallegos, G F

    2004-01-30

    The goal of this project was to investigate the chemical and structural effects of gallium and impurity elements, iron and nickel, on the phase behavior and crystallography of Pu-Ga alloys. This was done utilizing a theoretical chemical approach to predict binary and ternary alloy energetics, phase stability, and transformations. The modeling results were validated with experimental data derived from the synthesis of selected alloys and advanced characterization tools. The ultimate goal of this work was to develop a robust predictive capability for studying the thermodynamics and the structure-properties relationships in complex materials of high relevance to the Laboratory and DOE mission.

  12. Current assisted superplastic forming of titanium alloy

    Directory of Open Access Journals (Sweden)

    Wang Guofeng

    2015-01-01

    Full Text Available Current assisted superplastic forming combines electric heating technology and superplastic forming technology, and can overcome some shortcomings of traditional superplastic forming effectively, such as slow heating rate, large energy loss, low production efficiency, etc. Since formability of titanium alloy at room temperature is poor, current assisted superplastic forming is suitable for titanium alloy. This paper mainly introduces the application of current assisted superplastic forming in the field of titanium alloy, including forming technology of double-hemisphere structure and bellows.

  13. Electrochemical behaviour of passive zirconium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Patrito, E.M.; Torresi, R.M.; Leiva, E.P.M.; Macagno, V.A. (Universidad Nacional de Cordoba (Argentina). Inst. de Investigaciones en Fisicoquimica de Cordoba)

    1991-02-01

    The potentiodynamic oxidation of zirconium, zircaloy-2 (Zry-2) and zircaloy-4 (Zry-4) was studied in the O V{<=}V{<=}8 V potential range. Side reactions take place during the oxidation of Zry-2 and Zry-4 in phosphate electrolytes. With Zry-2, oxygen evolution occurs at high anodic potentials. The oxidation of the alloys in nitric acid shows dissolution of their minor alloying elements but no oxygen evolution at high potentials. The role played by the alloying elements in connection with the appearance of side reactions is discussed. The oxide film were characterized by impedance measurements, X-ray photoelectron spectroscopy and Auger spectroscopy. (author).

  14. Corrosion behavior of magnesium and magnesium alloys

    Institute of Scientific and Technical Information of China (English)

    I.M.Baghni; WU Yin-shun(吴荫顺); LI Jiu-qing(李久青); ZHANG Wei(张巍)

    2004-01-01

    The automotive industry has crossed the threshold from using magnesium alloys in interior applications such as instrument panels and steering wheels to unprotected environment such as oil pan, cylinder head and wheels. The expanding territory of magnesium leads to new challenges: mainly environmental degradation of the alloys used and how they can be protected. The present critical review is aimed at understanding the corrosion behavior of magnesium and magnesium alloys in industrial and marine environments, and the effect of microstructure, additive elements and inhibitors on the corrosion mechanism.

  15. Electrochemical Impedance Spectroscopy Of Metal Alloys

    Science.gov (United States)

    Macdowell, L. G.; Calle, L. M.

    1993-01-01

    Report describes use of electrochemical impedance spectroscopy (EIS) to investigate resistances of 19 alloys to corrosion under conditions similar to those of corrosive, chloride-laden seaside environment of Space Transportation System launch site. Alloys investigated: Hastelloy C-4, C-22, C-276, and B-2; Inconel(R) 600, 625, and 825; Inco(R) G-3; Monel 400; Zirconium 702; Stainless Steel 304L, 304LN, 316L, 317L, and 904L; 20Cb-3; 7Mo+N; ES2205; and Ferralium 255. Results suggest electrochemical impedance spectroscopy used to predict corrosion performances of metal alloys.

  16. New alloys to conserve critical elements

    Science.gov (United States)

    Stephens, J. R.

    1978-01-01

    Based on availability of domestic reserves, chromium is one of the most critical elements within the U.S. metal industry. New alloys having reduced chromium contents which offer potential as substitutes for higher chromium containing alloys currently in use are being investigated. This paper focuses primarily on modified Type 304 stainless steels having one-third less chromium, but maintaining comparable oxidation and corrosion properties to that of type 304 stainless steel, the largest single use of chromium. Substitutes for chromium in these modified Type 304 stainless steel alloys include silicon and aluminum plus molybdenum.

  17. Medical applications of shape memory alloys

    Directory of Open Access Journals (Sweden)

    Machado L.G.

    2003-01-01

    Full Text Available Shape memory alloys (SMA are materials that have the ability to return to a former shape when subjected to an appropriate thermomechanical procedure. Pseudoelastic and shape memory effects are some of the behaviors presented by these alloys. The unique properties concerning these alloys have encouraged many investigators to look for applications of SMA in different fields of human knowledge. The purpose of this review article is to present a brief discussion of the thermomechanical behavior of SMA and to describe their most promising applications in the biomedical area. These include cardiovascular and orthopedic uses, and surgical instruments.

  18. Magnetization curve modelling of soft magnetic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Meszaros, I, E-mail: meszaros@eik.bme.hu [Department of Materials Science and Engineering, Budapest University of Technology and Economics, Bertalan L. street 7., Budapest, H-1111 (Hungary)

    2011-01-01

    In this paper we present an application of the so called hyperbolic model of magnetization. The model was modified and it was applied for nine different soft magnetic alloys. The tested samples were electro-technical steels (FeSi alloys) and a permalloy (FeNi alloy) with strongly different magnetic properties. Among them there are top, medium and definitely poor quality soft magnetic materials as well. Their minor hysteresis loops and normal magnetization curves were measured by alternating current measurement. The hyperbolic model of magnetization was applied for the experimental normal magnetization curves. It was proved that the applied model is excellent for describing mathematically the experimental magnetization curves.

  19. Superelastic effect in polycrystalline ferrous alloys.

    Science.gov (United States)

    Omori, T; Ando, K; Okano, M; Xu, X; Tanaka, Y; Ohnuma, I; Kainuma, R; Ishida, K

    2011-07-01

    In superelastic alloys, large deformation can revert to a memorized shape after removing the stress. However, the stress increases with increasing temperature, which limits the practical use over a wide temperature range. Polycrystalline Fe-Mn-Al-Ni shape memory alloys show a small temperature dependence of the superelastic stress because of a small transformation entropy change brought about by a magnetic contribution to the Gibbs energies. For one alloy composition, the superelastic stress varies by 0.53 megapascal/°C over a temperature range from -196 to 240°C.

  20. Wear resistance of alloy вт-22 with non-ferrous alloys at reverse

    Directory of Open Access Journals (Sweden)

    А.М. Хімко

    2010-01-01

    Full Text Available  The article presents the results of tests of non hardened titanium alloy ВТ-22 with aviation non-ferrous alloys in reverse sliding friction. The main objective of the work is the selection of the optimum combination of materials depending on changes in loading conditions. Study of alloy ВТ-22 wear resistance was carried out in pairs with БрОФ-10-1, БрБ2, БрАЖ-9-4, ВТ-22, МЛ5, Д16Т, 7Х21ГАН5Ш and 95Х18Ш. The dependencies of the materials wear at pressures 10, 20 and 30 Mpa we determined. The linear nature of titanium alloy wear curves indicates that the change in the wear mechanism occurs gradually. The histograms of non-ferrous materials wear and the total wear of the friction pair are presented. It is established that the bronze БрАЖ-9-4 is the most preferable material for contact with non hardened titanium alloy ВТ-22, the least wear among the tested materials. The established coefficients of the titanium alloy ВТ-22 friction in pair with aviation structural non-ferrous alloys are presented. The results of research will be relevant for the engineering industry, where non hardened titanium alloy ВТ-22 in pair with non-ferrous alloys is applied.

  1. HAYNES 244 alloy – a new 760 ∘C capable low thermal expansion alloy

    Directory of Open Access Journals (Sweden)

    Fahrmann Michael G.

    2014-01-01

    Full Text Available HAYNES® 244TM alloy is a new 760∘C capable, high strength low thermal expansion (CTE alloy. Its nominal chemical composition in weight percent is Ni – 8 Cr – 22.5 Mo – 6 W. Recently, a first mill-scale heat of 244 alloy was melted by Haynes International, and processed to various product forms such as re-forge billet, plate, and sheet. This paper presents key attributes of this new alloy (CTE, strength, low-cycle fatigue performance, oxidation resistance, thermal stability as they pertain to the intended use in rings and seals of advanced gas turbines.

  2. Standard Specification for Electric Fusion-Welded Ni-Cr-Co-Mo Alloy (UNS N06617), Ni-Fe-Cr-Si Alloys (UNS N08330 and UNS N08332), Ni-Cr-Fe-Al Alloy (UNS N06603), Ni-Cr-Fe Alloy (UNS N06025), and Ni-Cr-Fe-Si Alloy (UNS N06045) Pipe

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2014-01-01

    Standard Specification for Electric Fusion-Welded Ni-Cr-Co-Mo Alloy (UNS N06617), Ni-Fe-Cr-Si Alloys (UNS N08330 and UNS N08332), Ni-Cr-Fe-Al Alloy (UNS N06603), Ni-Cr-Fe Alloy (UNS N06025), and Ni-Cr-Fe-Si Alloy (UNS N06045) Pipe

  3. Tuberculose e o estudo molecular da sua epidemiologia

    Directory of Open Access Journals (Sweden)

    J. R. Pandolfi

    2009-01-01

    Full Text Available

    A existência de sistemas que possam diferenciar cepas de Mycobacterium tuberculosis epidemiologicamente relacionadas daquelas não relacionadas, são ferramentas importantes. A tuberculose é uma doença infecciosa, na qual técnicas de biologia molecular permitem a obtenção de informações muito difíceis ou impossíveis de serem alcançadas pela epidemiologia clássica. Um método de tipagem discriminatório, baseado no DNA genômico bacteriano, denominado RFLP (polimorfismo de comprimento de fragmentos de restrição, é empregado no estudo epidemiológico da tuberculose. Entretanto esta técnica é trabalhosa e sua substituição é uma tendência. Assim, outras seqüências têm sido usadas como marcadores epidemiológicos, como na Spoligotyping, a qual é baseada na PCR, com hibridização diferencial subseqüente dos produtos amplificados. O polimorfismo observado nas diferentes amostras é provavelmente produto de recombinação homóloga. A técnica de MIRU (mycobacterial interspersed repetitive unit é um sistema rápido e reprodutível, onde ocorre a geração de genótipos baseados no estudo de 12 loci contendo VNTRs (número variável de repetições em seqüência do complexo M. tuberculosis. Ela compara as cepas de áreas geográficas diferentes e permite o rastreamento do movimento de linhagens individuais, como no RFLP. Este tipo de abordagem permite a análise de maior número de cepas e a identificação de um número maior de focos de contaminação dentro da população, propiciando melhores maneiras de frear a transmissão da doença. Palavras-chave: Mycobacterium tuberculosis; tuberculose; epidemiologia molecular; genotipagem.

  4. Estudos de medicamentos biosimilares Studies on biosimilar medications

    Directory of Open Access Journals (Sweden)

    Winston Bonetti Yoshida

    2010-09-01

    Full Text Available No Brasil, o registro de novos medicamentos é feito apenas quando a agência reguladora - Agência Nacional de Vigilância Sanitária (Anvisa - se satisfaz plenamente com as evidências de sua qualidade, eficácia e segurança, apresentadas por uma indústria farmacêutica que pleiteie esse registro. Com o vencimento de patentes, empresas farmacêuticas se sentem atraídas pela produção medicamentos biológicos chamados de biosimilares ou biogenéricos ou simplesmente genéricos, cuja aprovação pode resultar em redução de custos de tratamento. Mas é preciso que o biosimilar seja, pelo menos, igualmente eficaz e seguro e sem contaminantes em relação ao original. Consensos recentes apontam diretrizes para estabelecer critérios de eficácia e segurança desses medicamentos. Estudos pré-clínicos in vitro e in vivo, procedência da matéria-prima e estudos clínicos fase I, II e III são preconizados para registro do produto biosimilar no mercado internacional. As heparinas de baixo peso molecular encontram-se nessa situação. Nesta revisão, abordamos especificamente esse tipo de medicamento, o que pode servir de parâmetro para outros biosimilares.In Brazil, the registration of new drugs is carried out only when the regulatory agency (Anvisa, acronym in Portuguese is fully satisfied with the evidence of their quality, efficacy and safety, presented by a pharmaceutical industry that strive for this registration. With the patent expiration, pharmaceutical companies are attracted to produce biological medicines called biosimilar or biogenerics or simply generics, whose approval may result in reduced treatment costs. But it is necessary that the biosimilar be, at least, equally effective and safe and without contaminants in relation to the original. Recent consensus guidelines aim to establish criteria for efficacy and safety of these medicines. Preclinical studies in vitro and in vivo, the origin of raw materials and clinical studies

  5. ESTUDO DE CASO: PARCERIA COOXUPÉ/NESPRESSO NO CERRADO MINEIRO

    Directory of Open Access Journals (Sweden)

    KANESIRO, Lidiane Aparecida

    2010-04-01

    Full Text Available This study aimed to examine the partnership between the Swiss Company Nespresso and the Cooxupé Cooperative for the production of specialty coffee in the cerrado savannah, where the ones cooperatedCooxupé are the providers of these cafes. There were applied questionnaires for some producers with objectives question to evaluate to assess the difficulties in producing specialty coffee, to meet social demands, today almost mandatory when referring to products of high quality, is, generally know what you think of this partnership between the Cooperative Cooxupé and Nespresso. A search of bibliographic data was also used for reasons of this study. The results showed that the partnership was accepted by the producers, this partnership must be maintained and enhanced and that it should clarify the producers of the importance of investing in the environment. It can be verified that this work comes to be for the improvement of the partnership among the two companies involved in the study, and to conclude that the partnership was well accepts for the suppliers, could be perfected every year.Este trabalho teve por objetivo analisar a parceria firmada entre a Cooperativa Cooxupé e a Empresa suíça Nespresso para a produção de cafés especiais no cerrado mineiro, onde os próprios cooperados daCooxupé são os fornecedores destes cafés. Foram aplicados questionários com questões objetivas aos produtores da cooperativa com o intuito de avaliar as dificuldades em produzir cafés especiais, de cumprirem exigências sócio-ambientais, hoje praticamente obrigatórias quando se refere a produtos de qualidade, e saber o que acham desta parceria entre sua Cooperativa e a Nespresso. A pesquisa de dados bibliográficos também foi usada parafundamentação deste estudo. Os resultados obtidos mostraram que a parceria foi aceita pelos produtores; que tal parceria tem que ser mantida e aprimorada e que se deve esclarecer os produtores da importância em se

  6. Um estudo de construção da personagem a partir do movimento corporal

    OpenAIRE

    Ligia Losada Tourinho

    2004-01-01

    Resumo: Esta pesquisa apresenta um estudo sistemático sobre a construção da personagem nas Artes Cênicas, pelo prisma do movimento corporal, utilizando como principal suporte teórico e prático os estudos da Coreologia de Rudolf Von Laban e da Técnica de Stanislavski. Tomamos como base para a fundamentação teórica a idéia de o homem ser uma corporeidade, constituída pela Gestalt CORPO-MENTE-ESPÍRITO, presente nos estudos de Merleau-Ponty, nas consciências corporais e em todos aqueles que acred...

  7. Um estudo de construção da personagem a partir do movimento corporal

    OpenAIRE

    Ligia Losada Tourinho

    2004-01-01

    Esta pesquisa apresenta um estudo sistemático sobre a construção da personagem nas Artes Cênicas, pelo prisma do movimento corporal, utilizando como principal suporte teórico e prático os estudos da Coreologia de Rudolf Von Laban e da Técnica de Stanislavski. Tomamos como base para a fundamentação teórica a idéia de o homem ser uma corporeidade, constituída pela Gestalt CORPO-MENTE-ESPÍRITO, presente nos estudos de Merleau-Ponty, nas consciências corporais e em todos aqueles que acreditam na ...

  8. O texto traduzido sob a perspectiva do avaliador: um estudo exploratório

    OpenAIRE

    Camila Nathalia de Oliveira Braga

    2012-01-01

    Esta tese busca contribuir para os Estudos da Tradução, mais especificamente os estudos voltados para a avaliação de traduções, ao apresentar um estudo sobre o texto traduzido sob a perspectiva do avaliador. Para tanto, dezoito avaliadores (seis pesquisadores da área de Engenharia, seis linguistas / linguistas aplicados e seis tradutores profissionais) receberam a tarefa de avaliar oito traduções para o inglês de um resumo de uma tese da área de rejeitos radioativos escrito originalmente em p...

  9. Silver-hafnium braze alloy

    Science.gov (United States)

    Stephens, Jr., John J.; Hosking, F. Michael; Yost, Frederick G.

    2003-12-16

    A binary allow braze composition has been prepared and used in a bonded article of ceramic-ceramic and ceramic-metal materials. The braze composition comprises greater than approximately 95 wt % silver, greater than approximately 2 wt % hafnium and less than approximately 4.1 wt % hafnium, and less than approximately 0.2 wt % trace elements. The binary braze alloy is used to join a ceramic material to another ceramic material or a ceramic material, such as alumina, quartz, aluminum nitride, silicon nitride, silicon carbide, and mullite, to a metal material, such as iron-based metals, cobalt-based metals, nickel-based metals, molybdenum-based metals, tungsten-based metals, niobium-based metals, and tantalum-based metals. A hermetic bonded article is obtained with a strength greater than 10,000 psi.

  10. Shape memory alloy based motor

    Indian Academy of Sciences (India)

    S V Sharma; M M Nayak; N S Dinesh

    2008-10-01

    Design and characterization of a new shape memory alloy wire based Poly Phase Motor has been reported in this paper. The motor can be used either in stepping mode or in servo mode of operation. Each phase of the motor consists of an SMA wire with a spring in series. The principle of operation of the poly phase motor is presented. The motor resembles a stepper motor in its functioning though the actuation principles are different and hence has been characterized similar to a stepper motor. The motor can be actuated in either direction with different phase sequencing methods, which are presented in this work. The motor is modelled and simulated and the results of simulations and experiments are presented. The experimental model of the motor is of dimension 150 mm square, 20 mm thick and uses SMA wire of 0·4 mm diameter and 125 mm of length in each phase.

  11. Rapid solidification of immiscible alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bosco, Enrica; Rizzi, Paola; Baricco, Marcello E-mail: marcello.baricco@unito.it

    2003-05-01

    Immiscible alloys have been rapidly solidified for the preparation of granular materials with giant magnetoresistance properties. Au-based (Au-Co and Au-Fe) and Cu-based (Cu-Co and Cu-Fe) systems have been investigated. Single supersaturated solid solution has been obtained for Au-Fe, whereas three FCC solid solutions with different Co content have been found for Au-Co. For Cu-Co and Cu-Fe a limit of solubility in Cu has been observed. Ni additions to Cu-Fe strongly enhance solid solubility. A thermodynamic analysis has been used to describe the competition between partition-less solidification and phase separation in undercooled liquid.

  12. NASA-427: A New Aluminum Alloy

    Science.gov (United States)

    Nabors, Sammy A.

    2015-01-01

    NASA's Marshall Space Flight Center researchers have developed a new, stronger aluminum alloy, ideal for cast aluminum products that have powder or paint-baked thermal coatings. With advanced mechanical properties, the NASA-427 alloy shows greater tensile strength and increased ductility, providing substantial improvement in impact toughness. In addition, this alloy improves the thermal coating process by decreasing the time required for heat treatment. With improvements in both strength and processing time, use of the alloy provides reduced materials and production costs, lower product weight, and better product performance. The superior properties of NASA-427 can benefit many industries, including automotive, where it is particularly well-suited for use in aluminum wheels.

  13. Combustion synthesis of bulk nanocrystalline iron alloys

    Directory of Open Access Journals (Sweden)

    Licai Fu

    2016-02-01

    Full Text Available The controlled synthesis of large-scale nanocrystalline metals and alloys with predefined architecture is in general a big challenge, and making full use of these materials in applications still requires greatly effort. The combustion synthesis technique has been successfully extended to prepare large-scale nanocrystalline metals and alloys, especially iron alloy, such as FeC, FeNi, FeCu, FeSi, FeB, FeAl, FeSiAl, FeSiB, and the microstructure can be designed. In this issue, recent progress on the synthesis of nanocrystalline metals and alloys prepared by combustion synthesis technique are reviewed. Then, the mechanical and tribological properties of these materials with microstructure control are discussed.

  14. Solidification of Al alloys under electromagnetic field

    Institute of Scientific and Technical Information of China (English)

    崔建忠

    2003-01-01

    New theories and technology in the electromagnetic field were put forward about DC casting of Al alloys, including the fundamental research works, I.e, effects of the electromagnetic field on solidus and liquidus, macrosegregation of the main alloying elements, microstructures, content of alloying elements in grains and grain size after solidification under electromagnetic field, and also including a new process-DC casting under low frequency electromagnetic field(LFEMC), which can refine microstructure, eliminate macrosegregation, increase the content of alloying elements within grains, decrease the residual stress, avoid cracks and improve surface quality, and another new process-DC casting under low frequency electromagnetic vibration(LFEVC), which is a high effective method for grain refining.

  15. Theory of Rare-Earth Alloys

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker

    1977-01-01

    A mean-field random alloy theory combined with a simple calculation of the exchange interaction J(c,Q) is shown to quantitatively account for the phase diagrams for alloys of rare-earth metals with Y, Lu, Sc, and other rare-earth metals. A concentration-dependent J(c,Q) explains the empirical 2...... to account for all alloys except the Sc based. The exceptional behavior of the Sc alloys is due to a low density of states for Sc. A brief discussion is given of the effect on the mean-field results of changes in volume or c/a ratio and of critical fluctuations. Since the physical mechanisms of these ideal...

  16. Stress-corrosion cracking of titanium alloys.

    Science.gov (United States)

    Blackburn, M. J.; Feeney, J. A.; Beck, T. R.

    1973-01-01

    In the light of research material published up to May 1970, the current understanding of the experimental variables involved in the stress-corrosion cracking (SCC) behavior of titanium and its alloys is reviewed. Following a brief summary of the metallurgy and electrochemistry of titanium alloys, the mechanical, electrochemical, and metallurgical parameters influencing SCC behavior are explored with emphasis on crack growth kinetics. Macro- and microfeatures of fractures are examined, and it is shown that many transgranular SCC failures exhibit morphological and crystallographic features similar to mechanical cleavage failures. Current SCC models are reviewed with respect to their ability to explain the observed SCC behavior of titanium and its alloys. Possible methods for eliminating or minimizing stress corrosion hazards in titanium or titanium alloy components are described.

  17. On Silicides in High Temperature Titanium Alloys

    Directory of Open Access Journals (Sweden)

    C. Ramachandra

    1986-04-01

    Full Text Available High temperature titanium alloys like IMI 685 contain small amounts of silicon (~ 0.25 wt. per cent to improve creep resistance. Different types of silicides, namely Ti5Si3 (TiZr5Si3(S1 and (TiZr6 Si3 (S2, have been observed to precipitate in various silicon-bearing titanium alloys depending upon their composition and heat treatment. The precipitation of silicides, their orientation relationship with the matrix in different alloys, and the beneficial influence of thermo-mechanical treatment on the distribution of silicides have been pointed out. The effect of silicides on mechanical properties and fracture of the commercial alloy IMI 685 is also indicated.

  18. Optical Transmittance of Anodically Oxidized Aluminum Alloy

    Science.gov (United States)

    Saito, Mitsunori; Shiga, Yasunori; Miyagi, Mitsunobu; Wada, Kenji; Ono, Sachiko

    1995-06-01

    Optical transmittance and anisotropy of anodic oxide films that were made from pure aluminum and an aluminum alloy (A5052) were studied. The alloy oxide film exhibits an enhanced polarization function, particularly when anodization is carried out at a large current density. It was revealed by chemical analysis that the alloy oxide film contains a larger amount of unoxidized aluminum than the pure-aluminum oxide film. The polarization function can be elucidated by considering unoxidized aluminum particles that are arranged in the columnar structure of the alumina film. Electron microscope observation showed that many holes exist in the alloy oxide film, around which columnar cells are arranged irregularly. Such holes and irregular cell arrangement cause the increase in the amount of unoxidized aluminum, and consequently induces scattering loss.

  19. Ternary alloy nanocatalysts for hydrogen evolution reaction

    Indian Academy of Sciences (India)

    SOUMEN SAHA; SONALIKA VAIDYA; KANDALAM V RAMANUJACHARY; SAMUEL E LOFLAND; ASHOK K GANGULI

    2016-04-01

    Cu–Fe–Ni ternary alloys (size ∼55–80 nm) with varying compositions viz. CuFeNi (A1), CuFe2Ni (A2) and CuFeNi2 (A3) were successfully synthesized using microemulsion. It is to be noted that synthesis of nanocrystallineternary alloys with precise composition is a big challenge which can be overcome by choosing an appropriate microemulsion system. High electrocatalytic activity towards HER in alkaline medium was achieved by the formation of alloys of metals with low and high binding energies. A high value of current density (228 mA cm$^2$) at an overpotential of 545 mV was obtained for CuFeNi (A1), which is significantly high as compared to the previously reported Ni$_{59}$Cu$_{41}$ alloy catalyst.

  20. Combustion synthesis of bulk nanocrystalline iron alloys

    Institute of Scientific and Technical Information of China (English)

    Licai Fu; Jun Yang; Weimin Liu

    2016-01-01

    The controlled synthesis of large-scale nanocrystalline metals and alloys with predefined architecture is in general a big challenge, and making full use of these materials in applications still requires greatly effort. The combustion synthesis technique has been successfully extended to prepare large-scale nanocrystalline metals and alloys, especially iron alloy, such as FeC, FeNi, FeCu, FeSi, FeB, FeAl, FeSiAl, FeSiB, and the microstructure can be designed. In this issue, recent progress on the synthesis of nanocrystalline metals and alloys prepared by combustion synthesis technique are reviewed. Then, the mechanical and tribological properties of these materials with microstructure control are discussed.

  1. Shape Memory Alloy Rock Splitters (SMARS)

    Science.gov (United States)

    Benafan, Othmane (Inventor); Noebe, Ronald D. (Inventor)

    2017-01-01

    Shape memory alloys (SMAs) may be used for static rock splitting. The SMAs may be used as high-energy multifunctional materials, which have a unique ability to recover large deformations and generate high stresses in response to thermal loads.

  2. Thermal barrier coating for alloy systems

    Science.gov (United States)

    Seals, Roland D.; White, Rickey L.; Dinwiddie, Ralph B.

    2000-01-01

    An alloy substrate is protected by a thermal barrier coating formed from a layer of metallic bond coat and a top coat formed from generally hollow ceramic particles dispersed in a matrix bonded to the bond coat.

  3. High-entropy alloy: challenges and prospects

    Directory of Open Access Journals (Sweden)

    Y.F. Ye

    2016-07-01

    Full Text Available High-entropy alloys (HEAs are presently of great research interest in materials science and engineering. Unlike conventional alloys, which contain one and rarely two base elements, HEAs comprise multiple principal elements, with the possible number of HEA compositions extending considerably more than conventional alloys. With the advent of HEAs, fundamental issues that challenge the proposed theories, models, and methods for conventional alloys also emerge. Here, we provide a critical review of the recent studies aiming to address the fundamental issues related to phase formation in HEAs. In addition, novel properties of HEAs are also discussed, such as their excellent specific strength, superior mechanical performance at high temperatures, exceptional ductility and fracture toughness at cryogenic temperatures, superparamagnetism, and superconductivity. Due to their considerable structural and functional potential as well as richness of design, HEAs are promising candidates for new applications, which warrants further studies.

  4. Room temperature creep in metals and alloys

    Energy Technology Data Exchange (ETDEWEB)

    Deibler, Lisa Anne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Materials Characterization and Performance

    2014-09-01

    Time dependent deformation in the form of creep and stress relaxation is not often considered a factor when designing structural alloy parts for use at room temperature. However, creep and stress relaxation do occur at room temperature (0.09-0.21 Tm for alloys in this report) in structural alloys. This report will summarize the available literature on room temperature creep, present creep data collected on various structural alloys, and finally compare the acquired data to equations used in the literature to model creep behavior. Based on evidence from the literature and fitting of various equations, the mechanism which causes room temperature creep is found to include dislocation generation as well as exhaustion.

  5. Modeling wear of cast Ti alloys.

    Science.gov (United States)

    Chan, Kwai S; Koike, Marie; Okabe, Toru

    2007-05-01

    The wear behavior of Ti-based alloys was analyzed by considering the elastic-plastic fracture of individual alloys in response to the relevant contact stress field. Using the contact stresses as the process driving force, wear was computed as the wear rate or volume loss as a function of hardness and tensile ductility for Ti-based cast alloys containing an alpha, alpha+beta or beta microstructure with or without the intermetallic precipitates. Model predictions indicated that wear of Ti alloys increases with increasing hardness but with decreasing fracture toughness or tensile ductility. The theoretical results are compared with experimental data to elucidate the roles of microstructure in wear and contrasted against those in grindability.

  6. Simulation of nuclei morphologies for binary alloy

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    We study the critical nuclei morphologies of a binary alloy by the string method. The dynamic equation of the string, connecting the metastable phase (liquid) and stable phase (solid), is governed by Helmholtz free energy for the binary alloy system at a given temperature. The stationary string through the critical nucleus (saddle point) is obtained if the relaxation time of the string is su?ciently large. The critical nucleus radius and energy barrier to nucleation of a pure alloy with isotropic interface energy in two and three dimensions are calculated, which are consistent with the classical nucleation theory. The critical nuclei morphologies are sensitive to the anisotropy strength of interface energy and interface thickness of alloy in two and three dimensions. The critical nucleus and energy barrier to nucleation become smaller if the anisotropy strength of the interface energy is increased, which means that it is much easier to form a stable nucleus if the anisotropy of the interface energy is considered.

  7. Printability of alloys for additive manufacturing.

    Science.gov (United States)

    Mukherjee, T; Zuback, J S; De, A; DebRoy, T

    2016-01-22

    Although additive manufacturing (AM), or three dimensional (3D) printing, provides significant advantages over existing manufacturing techniques, metallic parts produced by AM are susceptible to distortion, lack of fusion defects and compositional changes. Here we show that the printability, or the ability of an alloy to avoid these defects, can be examined by developing and testing appropriate theories. A theoretical scaling analysis is used to test vulnerability of various alloys to thermal distortion. A theoretical kinetic model is used to examine predisposition of different alloys to AM induced compositional changes. A well-tested numerical heat transfer and fluid flow model is used to compare susceptibilities of various alloys to lack of fusion defects. These results are tested and validated with independent experimental data. The findings presented in this paper are aimed at achieving distortion free, compositionally sound and well bonded metallic parts.

  8. Solid solution lithium alloy cermet anodes

    Science.gov (United States)

    Richardson, Thomas J.

    2013-07-09

    A metal-ceramic composite ("cermet") has been produced by a chemical reaction between a lithium compound and another metal. The cermet has advantageous physical properties, high surface area relative to lithium metal or its alloys, and is easily formed into a desired shape. An example is the formation of a lithium-magnesium nitride cermet by reaction of lithium nitride with magnesium. The reaction results in magnesium nitride grains coated with a layer of lithium. The nitride is inert when used in a battery. It supports the metal in a high surface area form, while stabilizing the electrode with respect to dendrite formation. By using an excess of magnesium metal in the reaction process, a cermet of magnesium nitride is produced, coated with a lithium-magnesium alloy of any desired composition. This alloy inhibits dendrite formation by causing lithium deposited on its surface to diffuse under a chemical potential into the bulk of the alloy.

  9. Characteristics on Bi-Pb Based Alloys Quenched from Melt

    Institute of Scientific and Technical Information of China (English)

    Rizk Mostafa Shalaby

    2009-01-01

    Three different bismuth-lead systems namely, Wood's alloy (Bi50Pb25Sn12.5Cd12.5), Newton's alloy (Bi50Pb31.2Sn18.8) and Rose's alloy (Bi50Pb28Sn22), with one used as fusible alloys were quenched from melt by melt spinning technique. Thermal analysis, structure and mechanical properties of all alloys have been studied and analyzed. From X-ray diffraction analysis, an intermetallic compound phase, designated Pb7Bi3 is detected. The formation of an intermetallic compound phase causes a pronounced increase in the electrical resistivity. The Wood's alloy containing-cadmium exhibits mechanical properties superior to both the Newton's and Rose's alloys. The presence of cadmium in Wood's alloy decreases its melting point. Wood's alloy has better properties, which make it useful in various applications such as in protection shields for radiotherapy, locking of mechanical devices and welding at low temperature.

  10. Corrosion performance of structural alloys.

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.

    1999-07-15

    Component reliability and long-term trouble-free performance of structural materials are essential in power-generating and gasification processes that utilize coal as a feedstock. During combustion and conversion of coal, the environments encompass a wide range of oxygen partial pressures, from excess-air conditions in conventional boilers to air-deficient conditions in 10W-NO{sub x} and gasification systems. Apart from the environmental aspects of the effluent from coal combustion and conversion, one concern from the systems standpoint is the aggressiveness of the gaseous/deposit environment toward structural components such as waterwall tubes, steam superheaters, syngas coolers, and hot-gas filters. The corrosion tests in the program described in this paper address the individual and combined effects of oxygen, sulfur, and chlorine on the corrosion response of several ASME-coded and noncoded structural alloys that were exposed to air-deficient and excess-air environments typical of coal-combustion and gasification processes. Data in this paper address the effects of preoxidation on the subsequent corrosion performance of structural materials such as 9Cr-1Mo ferritic steel, Type 347 austenitic stainless steel, Alloys 800, 825, 625, 214, Hastelloy X, and iron aluminide when exposed at 650 C to various mixed-gas environments with and without HCI. Results are presented for scaling kinetics, microstructural characteristics of corrosion products, detailed evaluations of near-surface regions of the exposed specimens, gains in our mechanistic understanding of the roles of S and Cl in the corrosion process, and the effect of preoxidation on subsequent corrosion.

  11. Considerações metodológicas sobre o estudo de caso na pesquisa em psicoterapia

    OpenAIRE

    Serralta, Fernanda Barcellos; Nunes, Maria Lúcia Tiellet; Eizirik,Cláudio Laks

    2011-01-01

    O presente artigo faz uma revisão crítica da literatura acerca da aplicabilidade do estudo de caso na pesquisa em psicoterapia: a) apresenta as características do estudo de caso como estratégia de pesquisa; b) aborda a importância dos delineamentos de caso único no estudo do processo terapêutico; c) discute estatégias para aumentar a fidedignidade e validade dos estudos de caso; d) apresenta exemplos de estudos de caso oriundos da atual geração de pesquisa empírica em psicoterapia e psicanáli...

  12. Lightweight Protective Coatings For Titanium Alloys

    Science.gov (United States)

    Wiedemann, Karl E.; Taylor, Patrick J.; Clark, Ronald K.

    1992-01-01

    Lightweight coating developed to protect titanium and titanium aluminide alloys and titanium-matrix composite materials from attack by environment when used at high temperatures. Applied by sol-gel methods, and thickness less than 5 micrometers. Reaction-barrier and self-healing diffusion-barrier layers combine to protect titanium alloy against chemical attack by oxygen and nitrogen at high temperatures with very promising results. Can be extended to protection of other environmentally sensitive materials.

  13. Internal gettering by metal alloy clusters

    Science.gov (United States)

    Buonassisi, Anthony; Heuer, Matthias; Istratov, Andrei A.; Pickett, Matthew D.; Marcus, Mathew A.; Weber, Eicke R.

    2010-07-27

    The present invention relates to the internal gettering of impurities in semiconductors by metal alloy clusters. In particular, intermetallic clusters are formed within silicon, such clusters containing two or more transition metal species. Such clusters have melting temperatures below that of the host material and are shown to be particularly effective in gettering impurities within the silicon and collecting them into isolated, less harmful locations. Novel compositions for some of the metal alloy clusters are also described.

  14. Titanium and titanium alloys fundamentals and applications

    CERN Document Server

    Peters, Manfred

    2003-01-01

    This handbook is an excellent reference for materials scientists and engineers needing to gain more knowledge about these engineering materials. Following introductory chapters on the fundamental materials properties of titanium, readers will find comprehensive descriptions of the development, processing and properties of modern titanium alloys. There then follows detailed discussion of the applications of titanium and its alloys in aerospace, medicine, energy and automotive technology.

  15. Microstructure and Service Properties of Copper Alloys

    OpenAIRE

    Polok-Rubiniec M.; Konieczny J.; Labisz K.; Włodarczyk-Fligier A.

    2016-01-01

    This elaboration shows the effect of combined heat treatment and cold working on the structure and utility properties of alloyed copper. As the test material, alloyed copper CuTi4 was employed. The samples were subjected to treatment according to the following schema: 1st variant – supersaturation and ageing, 2nd variant – supersaturation, cold rolling and ageing. The paper presents the results of microstructure, hardness, and abrasion resistance. The analysis of the wipe profile geometry was...

  16. Mechanocaloric effects in Shape Memory Alloys

    OpenAIRE

    Manosa, Lluis; Planes, Antoni

    2016-01-01

    Shape memory alloys are a class of ferroic materials which undergo a structural (martensitic) transition where the associated ferroic property is a lattice distortion (strain). The sensitiveness of the transition to the conjugated external field (stress), together with the latent heat of the transition gives rise to giant mechanocaloric effects. In non-magnetic shape memory alloys, the lattice distortion is mostly described by a pure shear and the martensitic transition in this family of allo...

  17. Self-Organized Growth of Alloy Superlattices

    Energy Technology Data Exchange (ETDEWEB)

    Chason, E.; Floro, J.A.; Follstaedt, D.M.; Lagally, M.G.; Liu, F.; Tersoff, J.; Venezuela, P.

    1998-10-19

    We predict theoretically and demonstrate experimentally the spontaneous formation of a superlattice during crystal growth. When a strained alloy grows by "step flow", the steps at the surface form periodic bunches. The resulting modulated strain biases the incorporation of the respective alloy components at different steps in the bunch, leading to the formation of a superlattice. X-ray diffraction and electron microscopy for SiGe grown on Si give clear evidence for such spontaneous superlattice formation.

  18. Electrical Conductivity of Aluminium Alloy Foams

    Institute of Scientific and Technical Information of China (English)

    凤仪; 郑海务; 朱震刚; 祖方遒

    2002-01-01

    Closed-cell aluminium alloy foams were produced using the powder metallurgical technique. The effect of porosityand cell diameter on the electrical conductivity of foams was investigated and the results were compared with anumber of models. It was found that the percolation theory can be successfully applied to describe the dependenceof the electrical conductivity of aluminium alloy foams on the relative density. The cell diameter has a negligibleeffect on the electrical conductivity of foams.

  19. Phonon broadening in high entropy alloys

    Science.gov (United States)

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

    2017-09-01

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

  20. Pulse reversal plating of nickel alloys

    DEFF Research Database (Denmark)

    Tang, Peter Torben

    2007-01-01

    ), internal stress and material distribution are even more important. With baths based upon nickel chloride, and nickel and cobalt chlorides, pulse reversal plating of both pure nickel and nickel-cobalt alloys has been used to fabricate tools for microinjection moulding. Pulse reversal plating of ternary soft...... magnetic alloys, comprising 45-65%Co, 15-35%Fe and 15-35%Ni, is also reported....

  1. Novel Directional Solidification Processing of Hypermonotectic Alloys

    Science.gov (United States)

    Kaukler, William; Fedoseyev, Alex

    2002-01-01

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

  2. Alloys For Corrosive, Hydrogen-Rich Environments

    Science.gov (United States)

    Mcpherson, William B.; Bhat, Biliyar N.; Chen, Po-Shou; Kuruvilla, A. K.; Panda, Binayak

    1993-01-01

    "NASA-23" denotes class of alloys resisting both embrittlement by hydrogen and corrosion. Weldable and castable and formed by such standard processes as rolling, forging, and wire drawing. Heat-treated to obtain desired combinations of strength and ductility in ranges of 100 to 180 kpsi yield strength, 120 to 200 kpsi ultimate tensile strength, and 10 to 30 percent elongation at break. Used in place of most common aerospace structural alloy, Inconel(R) 718.

  3. Solid metal induced embrittlement of titanium alloys

    OpenAIRE

    Åkerfeldt, Pia

    2012-01-01

    Titanium alloys were for a time believed to be highly resistant to environmentally assisted cracking because of their ability to form a protective oxide film on the surface. Their resistance can still be considered to be high, but when cracking resistance was originally defined to ensure reliable functionality of fracture-critical components, certain conditions that promote cracking were discovered. One of the environmental assisted cracking processes relevant to titanium alloys is solid meta...

  4. Degassing of Aluminum Alloys Using Ultrasonic Vibration

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-06-01

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

  5. ESTUDO DA MATURIDADE DE PROCESSOS COBIT NA ELETROBRÁS

    Directory of Open Access Journals (Sweden)

    Fernando Cesar Almeida Silva

    2017-09-01

    Full Text Available Este artigo tem como objetivo descrever como foi realizado um estudo da maturidade dos processos CobiT em uma empresa do setor de energia elétrica do Brasil. Foi feita uma pesquisa onde os integrantes do Comitê de Tecnologia de Informação desta empresa informam sua percepção do nível de maturidade dos diversos processos existentes no CobiT. É realizada uma análise dos resultados onde é considerado o contexto no qual a empresa se insere. Para finalizar é proposto um sistema baseado no PDCA com o objetivo de aprimorar os processos que receberam classificação de avaliação mais baixa. A priorização de quais processos devem ser aprimorados primeiro, é baseada em critérios que levam em consideração os principais controles de ambiente do PCAOB, uma vez que esta empresa é auditada regularmente devido às obrigatoriedades da lei Sarbanes-Oxley.

  6. ESTUDO EM CLUSTERS TECNOLÓGICOS IBERO AMERICANOS

    Directory of Open Access Journals (Sweden)

    Fabio Lamartine Barbosa Toledo

    Full Text Available RESUMO O presente artigo analisa o índice de especialização e sua relação com inovação, internacionalização e a qualificação. Limitando-se a alguns setores inseridos nos clusters tecnológicos das regiões de Florianópolis/SC, Recife/PE, Região do Porto/Portugal e Região da Cataluña/Espanha, buscou-se verificar como o desenvolvimento da inovação (patentes submetidas, a internacionalização (volume de exportação e a qualificação (mestres e doutores nestas regiões relaciona-se com o índice de especialização das mesmas. Utilizou-se neste estudo um recorte longitudinal, no qual a evolução do índice de especialização foi analisado ao longo de um período de quatro anos e confrontado com os indicadores: qualificação, internacionalização e inovação. Foram formuladas três hipóteses, as quais foram testadas por meio do tratamento dos dados obtidos nas regiões dos quatro clusters pesquisados.

  7. Raiva humana: estudo neuropatológico de trinta casos

    Directory of Open Access Journals (Sweden)

    R. V. C. Assis

    1984-12-01

    Full Text Available O estudo epidemiológico e neuropatológico concernente a trinta autópsias de encefalite rábica foi realizado, tendo sido os dados obtidos comparados com aqueles da literatura. Não houve relação estatística entre a topografia lesional e o local da mordida, entre o período de incubação ou a duração da doença e a presença ou ausência de inclusões virais (IV assim como entre a intensidade do processo inflamatorio (PI e a presença de IV. A dispersão do PI e das IV através o SNC foi diretamente proporcional à sua intensidade. A estrutura mais freqüentemente comprometida pelo PI foi o mesencéfalo, seguido pelo bulbo, ponte e medula espinhal. A estrutura mais intensamente afetada foi o bulbo. As IV foram particularmente proeminentes no hipocampo e cerebelo.

  8. Trabalho e riscos de adoecimento: um estudo entre policiais civis

    Directory of Open Access Journals (Sweden)

    Vânia Cristine Cavalcante Anchieta

    Full Text Available Este estudo teve como objetivo avaliar a percepção que os policiais civis do DF têm sobre o seu contexto de trabalho, suas exigências, assim como as vivências e os problemas físicos, psicológicos e sociais causados pelo trabalho, procurando fazer inferências sobre as estratégias de mediação utilizadas para evitar o sofrimento e os riscos de adoecimento. Foi aplicado o Inventário do Trabalho e Riscos de Adoecimento (ITRA em 160 policiais civis, homens e mulheres, recém empossados na Instituição (tempo médio de oito meses de ingresso na Instituição. Os resultados indicaram que, apesar de não ficarem evidentes danos graves à saúde do policial novato, há riscos de acontecerem falhas nas estratégias de mediação em relação a fatores que levam ao adoecimento.

  9. Estudo de usuários on line

    Directory of Open Access Journals (Sweden)

    Bruno Macedo Nathansohn

    2005-07-01

    Full Text Available Trata-se de um estudo de usuários baseado na perspectiva da responsabilidade social da Ciência da Informação, considerando um agregado de informação disponível na Internet. O objetivo foi o levantamento do perfil dos usuários, para detectar suas preferências em relação ao sítio, assim como a investigação sobre o uso que se faz de um espaço que produz informação política, econômica e social. Para tanto, foram desenvolvidos mecanismos de interatividade para que, ao mesmo tempo em que houvesse a coleta de dados por parte do profissional da informação proporcionasse a participação, por parte dos usuários, para a possibilidade de transformar a estrutura desse agregado. Processo que se baseou na metodologia da Pesquisa-Ação, identificando e apresentando as barreiras na comunicação, como resultado final do processo de intervenção científica.

  10. ESTUDO DE EVENTOS CO-SISMOGÊNICOS BRASILEIROS

    Directory of Open Access Journals (Sweden)

    Thiago de Almeida Santos

    2017-02-01

    Full Text Available Este trabalho, relacionado com o evento sísmico de 16 de Setembro de 2015, em Illapel, Chile, foca na análise de variações geomagnéticas, principalmente na caracterização e situação em que se dão, a fim de contribuir para uma melhor compreensão dos processos físicos envolvidos no acoplamento Litosfera-Atmosfera-Ionosfera (LAI. Para isto, foram utilizados registros de magnetômetros fluxgate medidos em superfície fornecido pela rede EMBRACE. A metodologia de análise consiste na decomposição do sinal por bandas de frequência, isto é, Decomposição de Modo Empírico (EMD. O resultado alcançado no momento é a caracterização de efeitos magnéticos co-sismogênicos em território brasileiro causados pelo evento sísmico citado. Portanto, estudos como este se mostram indispensáveis e importantes não apenas no ponto de vista científico, mas também pela possibilidade de contribuição para uma futura condição de previsão e de potencial de alerta de catástrofes.

  11. Do Antissocialismo ao Anticapitalismo: um estudo sobre a Rerum Novarum

    Directory of Open Access Journals (Sweden)

    Claudinei Magno Magre Mendes

    2016-05-01

    Full Text Available O objetivo deste artigo é examinar o processo de constituição do anticapitalismo por meio da análise da Rerum Novarum, a primeira encíclica social. Comparando esta com as encíclicas anteriores do século XIX, pudemos estabelecer o que ela trouxe de novidade no que diz respeito ao combate que a Igreja travava contra o socialismo. Com essa comparação, foi possível caracterizar a postura anticapitalista, confrontando a nossa maneira de concebê-la com as demais. Para o exame da Rerum Novarum foi igualmente importante analisar alguns estudos referentes a ela, tanto os que apareceram logo após a sua publicação como os que foram realizados em décadas mais recentes. Como conclusão, definimos o anticapitalismo como uma atitude que somente poderia ter surgido em condições sociais e políticas bastante particulares e que apenas apareceram em fins do século XIX.

  12. Estudo retrospectivo da peste humana no Nordeste oriental do Brasil

    Directory of Open Access Journals (Sweden)

    Dalva A. Mello

    1970-02-01

    Full Text Available Utilizando dados do Departamento Nacional de Endemias Rurais, o autor faz um estudo retrospectivo da peste humana no Nordeste Oriental do Brasil no período de 1935-1967. Os aspectos epidemiológicos abordados foram os seguintes: morbidade, mortalidade, letalidade, "point" epidêmicos, tendência secular e variações mensais. Os coeficientes de morbidade e mortalidade variaram muito. A letalidade apresentou-se bastante alta. Dez anos de "point" epidêmicos foram registrados no periodo estudado. A análise estatística dos casos distribuídos por mês mostrou que a peste humana atinge o pcnto máximo na estação sêca. Ficou demonstrada urna variação cíclica da doença, em que aumentos e decréscimos ocorrem em períodos que variam de 6 a 12 anos.

  13. Estudo da auditoria de contas em um hospital de ensino

    Directory of Open Access Journals (Sweden)

    Gabriela Favaro Faria Guerrer

    2015-06-01

    Full Text Available RESUMOObjetivos:verificar os itens componentes das contas hospitalares, conferidos por enfermeiros auditores, que mais recebem ajustes no momento da pré-análise; identificar o impacto dos ajustes no faturamento das contas analisadas por enfermeiros e médicos auditores e identificar as glosas relacionadas aos itens conferidos pela equipe de auditoria.Método:pesquisa quantitativa exploratória, descritiva, do tipo estudo de caso único.Resultados:após a análise de 2.613 contas constatou-se que o item mais incluído por enfermeiros foram gases (90,5% e o mais excluído medicamentos de internação (41,2%. Materiais de hemodinâmica; gases e equipamentos foram os que mais impactaram nos ajustes positivos. Os ajustes negativos decorreram de lançamentos indevidos nas contas e não geraram prejuízos de faturamento. Do total de glosas 52,24% referiu-se à pré-análise dos enfermeiros e 47,76% a dos médicos.Conclusão:a presente investigação do processo de pré-análise fornece subsídios que contribuem para o avanço no conhecimento sobre a auditoria de contas hospitalares.

  14. Initial cytotoxicity of novel titanium alloys.

    Science.gov (United States)

    Koike, M; Lockwood, P E; Wataha, J C; Okabe, T

    2007-11-01

    We assessed the biological response to several novel titanium alloys that have promising physical properties for biomedical applications. Four commercial titanium alloys [Super-TIX(R) 800, Super-TIX(R) 51AF, TIMETAL(R) 21SRx, and Ti-6Al-4V (ASTM grade 5)] and three experimental titanium alloys [Ti-13Cr-3Cu, Ti-1.5Si and Ti-1.5Si-5Cu] were tested. Specimens (n = 6; 5.0 x 5.0 x 3.0 mm(3)) were cast in a centrifugal casting machine using a MgO-based investment and polished to 600 grit, removing 250 mum from each surface. Commercially pure titanium (CP Ti: ASTM grade 2) and Teflon (polytetrafluoroethylene) were used as positive controls. The specimens were cleaned and disinfected, and then each cleaned specimen was placed in direct contact with Balb/c 3T3 fibroblasts for 72 h. The cytotoxicity [succinic dehydrogenase (SDH) activity] of the extracts was assessed using the MTT method. Cytotoxicity of the metals tested was not statistically different compared to the CP Ti and Teflon controls (p > 0.05). These novel titanium alloys pose cytotoxic risks no greater than many other commonly used alloys, including commercially pure titanium. The promising short-term biocompatibility of these Ti alloys is probably due to their excellent corrosion resistance under static conditions, even in biological environments.

  15. Capacity retention in hydrogen storage alloys

    Science.gov (United States)

    Anani, A.; Visintin, A.; Srinivasan, S.; Appleby, A. J.; Reilly, J. J.; Johnson, J. R.

    1992-01-01

    Results of our examination of the properties of several candidate materials for hydrogen storage electrodes and their relation to the decrease in H-storage capacity upon open-circuit storage over time are reported. In some of the alloy samples examined to date, only about 10 percent of the hydrogen capacity was lost upon storage for 20 days, while in others, this number was as high as 30 percent for the same period of time. This loss in capacity is attributed to two separate mechanisms: (1) hydrogen desorbed from the electrode due to pressure differences between the cell and the electrode sample; and (2) chemical and/or electrochemical degradation of the alloy electrode upon exposure to the cell environment. The former process is a direct consequence of the equilibrium dissociation pressure of the hydride alloy phase and the partial pressure of hydrogen in the hydride phase in equilibrium with that in the electrolyte environment, while the latter is related to the stability of the alloy phase in the cell environment. Comparison of the equilibrium gas-phase dissociation pressures of these alloys indicate that reversible loss of hydrogen capacity is higher in alloys with P(eqm) greater than 1 atm than in those with P(eqm) less than 1 atm.

  16. Surface energy of metal alloy nanoparticles

    Science.gov (United States)

    Takrori, Fahed M.; Ayyad, Ahmed

    2017-04-01

    The measurement of surface energy of alloy nanoparticles experimentally is still a challenge therefore theoretical work is necessary to estimate its value. In continuation of our previous work on the calculation of the surface energy of pure metallic nanoparticles we have extended our work to calculate the surface energy of different alloy systems, namely, Co-Ni, Au-Cu, Cu-Al, Cu-Mg and Mo-Cs binary alloys. It is shown that the surface energy of metallic binary alloy decreases with decreasing particle size approaching relatively small values at small sizes. When both metals in the alloy obey the Hume-Rothery rules, the difference in the surface energy is small at the macroscopic as well as in the nano-scale. However when the alloy deviated from these rules the difference in surface energy is large in the macroscopic and in the nano scales. Interestingly when solid solution formation is not possible at the macroscopic scale according to the Hume-Rothery rules, it is shown it may form at the nano-scale. To our knowledge these findings here are presented for the first time and is challenging from fundamental as well as technological point of views.

  17. Point-charge electrostatics in disordered alloys

    CERN Document Server

    Wolverton, C; Froyen, S; Wei, S H; Zunger, Alex

    1996-01-01

    A simple analytic model of point-ion electrostatics has been previously proposed in which the magnitude of the net charge q_i on each atom in an ordered or random alloy depends linearly on the number N_i^(1) of unlike neighbors in its first coordination shell. Point charges extracted from recent large supercell (256-432 atom) local density approximation (LDA) calculations of Cu-Zn random alloys now enable an assessment of the physical validity and accuracy of the simple model. We find that this model accurately describes (i) the trends in q_i vs. N_i^(1), particularly for fcc alloys, (ii) the magnitudes of total electrostatic energies in random alloys, (iii) the relationships between constant-occupation-averaged charges and Coulomb shifts (i.e., the average over all sites occupied by either $A$ or $B$ atoms) in the random alloy, and (iv) the linear relation between the site charge q_i and the constant- charge-averaged Coulomb shift (i.e., the average over all sites with the same charge) for fcc alloys. Howe...

  18. Biocorrosion study of titanium-cobalt alloys.

    Science.gov (United States)

    Chern Lin, J H; Lo, S J; Ju, C P

    1995-05-01

    The present work provides experimental results of corrosion behaviour in Hank's physiological solution and some other properties of in-house fabricated titanium-cobalt alloys with cobalt ranging from 25-30% in weight. X-ray diffraction (XRD) shows that, in water-quenched (WQ) alloys, beta-titanium is largely retained, whereas in furnace-cooled (FC) alloys, little beta-titanium is found. Hardness of the alloys increases with increasing cobalt content, ranging from 455 VHN for WQ Ti-25 wt% Co to 525 VHN for WQ Ti-30 wt% Co. Differential thermal analysis (DTA) indicates that melting temperatures of the alloys are lower than that of pure titanium by about 600 degrees C. Potentiodynamic polarization results show that all measured break-down potentials in Hank's solution at 37 degrees C are higher than 800 mV. The breakdown potential for the FC Ti-25 Wt% Co alloy is even as high as nearly 1200 mV.

  19. Hydrogen storage systems from waste Mg alloys

    Science.gov (United States)

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

    2014-12-01

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

  20. Comparison of the Oxidation Rates of Some New Copper Alloys

    Science.gov (United States)

    Ogbuji, Linus U. J. Thomas; Humphrey, Donald L.

    2002-01-01

    Copper alloys were studied for oxidation resistance and mechanisms between 550 and 700 C, in reduced-oxygen environments expected in rocket engines, and their oxidation behaviors compared to that of pure copper. They included two dispersion-strengthened alloys (precipitation-strengthened and oxide-dispersion strengthened, respectively) and one solution-strengthened alloy. In all cases the main reaction was oxidation of Cu into Cu2O and CuO. The dispersion-strengthened alloys were superior to both Cu and the solution-strengthened alloy in oxidation resistance. However, factors retarding oxidation rates seemed to be different for the two dispersion-strengthened alloys.

  1. An Analysis of Selected Properties of ZA Alloys

    Science.gov (United States)

    Gervais, E.; Barnhurst, R. J.; Loong, C. A.

    1985-11-01

    Zinc-aluminum (ZA) alloys are a relatively new family of zinc foundry alloys having superior melting and casting characteristics and attractive mechanical properties. The ZA-8 and ZA-12 alloys are moderate to high strength materials while ZA-27 is a high-strength alloy. All can be sand cast, permanent molded and pressure die cast. An extensive characterization program is being implemented to develop appropriate and reliable engineering data for designers. Property development in all aspects of ZA metallurgy is welladvanced. The data available on selected physical and mechanical properties of ZA alloys is compared here with the properties of traditional casting alloys.

  2. Study of fatigue behaviour of 7475 aluminium alloy

    Indian Academy of Sciences (India)

    B B Verma; J D Atkinson; M Kumar

    2001-04-01

    Fatigue properties of a thermomechanically treated 7475 aluminium alloy have been studied in the present investigation. The alloy exhibited superior fatigue life compared to conventional structural aluminium alloys and comparable stage II crack growth rate. It was also noticed that the fatigue crack initiated from a surface grain and the crack extension was dominated by ductile striations. Analysis also revealed that this alloy possessed fracture toughness and tensile properties superior to that noticed with other structural aluminium alloys. Therefore the use of this alloy can safely reduce the overall weight of the aircraft.

  3. Nondestructive Evaluation of Ni-Ti Shape Memory Alloy

    Science.gov (United States)

    Meir, S.; Gordon, S.; Karsh, M.; Wiezman, A.; Ayers, R.; Olson, D. L.

    2011-06-01

    The nondestructive evaluation of nickel titanium (Ni-Ti) alloys for applications such as heat treatment for biomaterials applications (dental) and welding was investigated. Ni-Ti alloys and its ternary alloys are valued for mechanical properties in addition to the shape memory effect. Two analytical approaches were perused in this work. Assessment of the microstructure of the alloy that determines the martensitic start temperature (Ms) of Ni-Ti alloy as a function of heat treatment, and secondly, an attempt to evaluate a Friction Stir Welding, which involves thermo-mechanical processing of the alloy.

  4. Study on microstructure and properties of Mg-alloy surface alloying layer fabricated by EPC

    Directory of Open Access Journals (Sweden)

    Chen Dongfeng

    2010-02-01

    Full Text Available AZ91D surface alloying was investigated through evaporative pattern casting (EPC technology. Aluminum powder (0.074 to 0.104 mm was used as the alloying element in the experiment. An alloying coating with excellent properties was fabricated, which mainly consisted of adhesive, co-solvent, suspending agent and other ingredients according to desired proportion. Mg-alloy melt was poured under certain temperature and the degree of negative pressure. The microstructure of the surface layer was examined by means of scanning electron microscopy. It has been found that a large volume fraction of network new phases were formed on the Mg-alloy surface, the thickness of the alloying surface layer increased with the alloying coating increasing from 0.3 mm to 0.5 mm, and the microstructure became compact. Energy dispersive X-ray (EDX analysis was used to determine the chemical composition of the new phases. It showed that the new phases mainly consist of β-Mg17Al12, in addition to a small quantity of inter-metallic compounds and oxides. A micro-hardness test and a corrosion experiment to simulate the effect of sea water were performed. The result indicated that the highest micro-hardness of the surface reaches three times that of the matrix. The corrosion rate of alloying samples declines to about a fifth of that of the as-cast AZ91D specimen.

  5. Entropies in Alloy Design for High-Entropy and Bulk Glassy Alloys

    Directory of Open Access Journals (Sweden)

    Akihiro Makino

    2013-09-01

    Full Text Available High-entropy (H-E alloys, bulk metallic glasses (BMGs and high-entropy BMGs (HE-BMGs were statistically analyzed with the help of a database of ternary amorphous alloys. Thermodynamic quantities corresponding to heat of mixing and atomic size differences were calculated as a function of composition of the multicomponent alloys. Actual calculations were performed for configurational entropy (Sconfig. in defining the H-E alloys and mismatch entropy (Ss normalized with Boltzmann constant (kB, together with mixing enthalpy (DHmix based on Miedema’s empirical model and Delta parameter (d as a corresponding parameter to Ss/kB. The comparison between DHmix–d and DHmix–  diagrams for the ternary amorphous alloys revealed Ss/kB ~ (d /222. The zones S, S′ and B’s where H-E alloys with disordered solid solutions, ordered alloys and BMGs are plotted in the DHmix–d diagram are correlated with the areas in the DHmix – Ss /kB diagram. The results provide mutual understandings among H-E alloys, BMGs and HE-BMGs.

  6. Oxidation resistant coating for titanium alloys and titanium alloy matrix composites

    Science.gov (United States)

    Brindley, William J. (Inventor); Smialek, James L. (Inventor); Rouge, Carl J. (Inventor)

    1992-01-01

    An oxidation resistant coating for titanium alloys and titanium alloy matrix composites comprises an MCrAlX material. M is a metal selected from nickel, cobalt, and iron. X is an active element selected from Y, Yb, Zr, and Hf.

  7. Improvement of magnetocaloric properties of Gd-Ge-Si alloys by alloying with iron

    Directory of Open Access Journals (Sweden)

    Erenc-Sędziak T.

    2013-01-01

    Full Text Available The influence of annealing of Gd5Ge2Si2Fex alloys at 1200°C and of alloying with various amount of iron on structure as well as thermal and magnetocaloric properties is investigated. It was found that annealing for 1 to 10 hours improves the entropy change, but reduces the temperature of maximum magnetocaloric effect by up to 50 K. Prolonged annealing of the Gd5Ge2Si2 alloy results in the decrease of entropy change due to the reduction of Gd5Ge2Si2 phase content. Addition of iron to the ternary alloy enhances the magnetocaloric effect, if x = 0.4 – 0.6, especially if alloying is combined with annealing at 1200°C: the peak value of the isothermal entropy change from 0 to 2 T increases from 3.5 to 11 J/kgK. Simultaneously, the temperature of maximum magnetocaloric effect drops to 250 K. The changes in magnetocaloric properties are related to the change in phase transformation from the second order for arc molten ternary alloy to first order in the case of annealed and/or alloyed with iron. The results of this study indicate that the minor addition of iron and heat treatment to Gd-Ge-Si alloys may be useful in improving the materials’ magnetocaloric properties..

  8. Corrosion Behavior of Au, Hastelloy C-276 Alloy and Monel 400 Alloy in Molten Lithium Fluoride

    Institute of Scientific and Technical Information of China (English)

    WANG; Chang-shui; GUO; Jun-kang

    2013-01-01

    For searching better corrosion-resistant material in high temperature,we investigated the corrosion behavior of Au,Haynes C-276 alloy and Monel 400 alloy in molten lithium fluoride at 950℃.The corrosion products and fine structures of the corroded specimens were characterized by inductively coupled plasma mass spectrometry(ICP-MS),scanning electron microscope(SEM),energy dispersive

  9. Effect of Alloying Elements on Nano-ordered Wear Property of Magnesium Alloys

    Science.gov (United States)

    Yagi, Takahiro; Hirayama, Tomoko; Matsuoka, Takashi; Somekawa, Hidetoshi

    2017-03-01

    The effect of alloying elements on nano-ordered wear properties was investigated using fine-grained pure magnesium and several types of 0.3 at. pct X (X = Ag, Al, Ca, Li, Mn, Y, and Zn) binary alloys. They had an average grain size of 3 to 5 μm and a basal texture due to their production by the extrusion process. The specific wear rate was influenced by the alloying element; the Mg-Ca and Mg-Mn alloys showed the best and worst wear property, respectively, among the present alloying elements, which was the same trend as that for indentation hardness. Deformed microstructural observations revealed no formation of deformation twins, because of the high activation of grain boundary-induced plasticity. On the contrary, according to scratched surface observations, when grain boundary sliding partially contributed to deformation, these alloys had large specific wear rates. These results revealed that the wear property of magnesium alloys was closely related to the plastic deformation mechanism. The prevention of grain boundary sliding is important to improve the wear property, which is the same as that of a large-scale wearing configuration. One of the influential factors is the change in the lattice parameter with the chemical composition, i.e., ∂( c/ a)/∂ C. An alloying element that has a large value of ∂( c/ a)/∂ C effectively enhances the wear property.

  10. Effect of alloying addition and microstructural parameters on mechanical properties of 93% tungsten heavy alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ravi Kiran, U., E-mail: uravikiran@gmail.com [Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad 500 058 (India); Panchal, A.; Sankaranarayana, M. [Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad 500 058 (India); Nageswara Rao, G.V.S. [National Institute of Technology, Warangal 506004 (India); Nandy, T.K. [Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad 500 058 (India)

    2015-07-29

    Liquid phase sintering, heat treatment and swaging studies on three tungsten heavy alloys, 93W–4.9Ni–2.1Fe (wt%), 93W–4.2Ni–1.2Fe–1.6Co (wt%) and 93W–4.9Ni–1.9Fe–0.2Re (wt%) were carried out in detail with respect to microstructure, tensile and impact properties. All the alloys were sintered and swaged to 40% deformation. The results indicate that Re addition reduces the grain size of the alloy compared to W–Ni–Fe and W-Ni-Fe-Co alloys. W–Ni–Fe–Re alloy shows superior tensile properties in heat treated condition as compared to W–Ni–Fe and W–Ni–Fe–Co alloys. SEM study of fractured specimens clearly indicates that the failure in case of W–Ni–Fe–Re was due to transgranular cleavage of tungsten grains and W–W de-cohesion. W–Ni–Fe and W–Ni–Fe–Co alloys also failed by mixed mode failure. However, in these cases, ductile dimples corresponding the failure of the matrix phase was rarely seen. Thermo-mechanical processing resulted in significant changes in mechanical properties. While W–Ni–Fe–Re alloy showed the highest tensile strength (1380 MPa), W–Ni–Fe–Co exhibited the highest elongation (12%) to failure. A detailed analysis involving microstructure, mechanical properties and failure behavior was undertaken in order to understand the property trends.

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

    DEFF Research Database (Denmark)

    1997-01-01

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

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

    DEFF Research Database (Denmark)

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

    1996-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-05-15

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

  14. Effect of alloy elements on the anti-corrosion properties of low alloy steel

    Indian Academy of Sciences (India)

    Baorong Hou; Yantao Li; Yanxu Li; Jinglei Zhang

    2000-06-01

    Effect of alloy elements on corrosion of low alloy steel was studied under simulated offshore conditions. The results showed that the elements Cu, P, Mo, W, V had evident effect on corrosion resistance in the atmosphere zone; Cu, P, V, Mo in the splash zone and Cr, Al, Mo in the submerged zone.

  15. Estudo do fluxo salivar, status periodontal e prevalência de lesões orais de doentes VIH1 e VIH2 naives: estudo seccional cruzado

    OpenAIRE

    Ferreira, Cristina Gutierrez Castanheira

    2013-01-01

    Tese de mestrado, Medicina Dentária, Universidade de Lisboa, Faculdade de Medicina Dentária, 2013 Objetivo: Identificar alterações do fluxo salivar estimulado, alterações periodontais e caracterizar padrões de doença oral associados ou não à infecção por VIH em doentes VIH1 e VIH2 naives. Desenho de estudo: Estudo Observacional Seccional Cruzado Materiais e métodos: A amostra foi constituída por 70 participantes, (N=70) dos quais 27 VIH1 e 24 VIH2 naives (sem terapia anti-retroviral) recru...

  16. ESTRESSE NO TRABALHO: ESTUDO COM TAXISTAS NA CIDADE DE BELO HORIZONTE

    National Research Council Canada - National Science Library

    Juliana Celeste de Matos Braga; Luciano Pereira Zille

    2015-01-01

    ... estratégias de enfrentamento de taxistas que atuam na cidade de Belo Horizonte/MG. Em termos metodológicos, trata-se de um estudo descritivo-explicativo, com abordagem quantitativa e qualitativa, envolvendo 458 taxistas...

  17. Lesões esportivas: um estudo com atletas do basquetebol bauruense

    Directory of Open Access Journals (Sweden)

    Bruno Estevan Siqueira Dario

    2010-05-01

    Full Text Available Este estudo teve como objetivo identificar as principais lesões no basquetebol e suas incidências. Participaram do estudo vinte jogadores de basquetebol do sexo masculino com idade variando entre 13 e 15 anos. O instrumento utilizado foi o questionário e seus resultados mostraram que, dos atletas participantes do estudo, todos relataram algum tipo de lesão. Foram identificadas 26 lesões, sendo 13 nos membros inferiores (50% e 13 nos membros superiores (50%. No joelho, as lesões mais frequentes foram a tendinite patelar - sete casos (53,85%. Nos membros superiores, destacaram-se as entorses nos dedos das mãos - cinco casos (38,46%. Com este estudo, percebemos a necessidade de se desenvolver um trabalho preventivo no intuito de diminuir a incidência dessas lesões.

  18. COMPORTAMENTO DO CONSUMIDOR ENDIVIDADO: UM ESTUDO EXPLORATÓRIO COM INDIVÍDUOS DE BAIXA RENDA

    Directory of Open Access Journals (Sweden)

    Celso Augusto de Matos

    2015-02-01

    Full Text Available O presente estudo teve como objetivo geral analisar os fatores associados ao superendividamento de consumidores de baixa renda. Foi realizado um estudo exploratório, de cunho qualitativo, por meio de entrevistas individuais com consumidores das classes D e E. Dentre os principais fatores associados ao acúmulo de dívidas pelos entrevistados, destacam-se as compras por impulso, o pagamento do valor mínimo das faturas do cartão de crédito, o uso de financiamentos e empréstimos para aquisição de bens ou até mesmo para pagar outra dívida e fatores imprevistos. O estudo termina com uma discussão teórica destes resultados e sugestões de pesquisa para estudos futuros.

  19. Thermophysical Properties of Matter - the TPRC Data Series. Volume 12. Thermal Expansion Metallic Elements and Alloys

    Science.gov (United States)

    1975-01-01

    alloys--erawy--Molybdeum--M.1ybdmm alloys--Neodymium-- Nickel--Nickel alloys-Niobum-Niobium alloys--Palladiua--Palladum alloys- Platin-- Platium alloys...98 220 Palladium-Silver Pd-Ag................962 221* Platiu-Rhodium Pt-Rh..................987 222 Platium -Rutbentum Pt-Ru

  20. Alloy development for irradiation performance. Quarterly progress report for period ending December 31, 1980

    Energy Technology Data Exchange (ETDEWEB)

    1981-04-01

    Progress is reported in eight sections: analysis and evaluation studies, test matrices and test methods development, Path A Alloy Development (austenitic stainless steels), Path C Alloy Development (Ti and V alloys), Path D Alloy Development (Fe alloys), Path E Alloy Development (ferritic steels), irradiation experiments and materials inventory, and materials compatibility and hydrogen permeation studies. (DLC)

  1. Alloy development for irradiation performance. Quarterly progress report for period ending December 31, 1980

    Energy Technology Data Exchange (ETDEWEB)

    1981-04-01

    Progress is reported in eight sections: analysis and evaluation studies, test matrices and test methods development, Path A Alloy Development (austenitic stainless steels), Path C Alloy Development (Ti and V alloys), Path D Alloy Development (Fe alloys), Path E Alloy Development (ferritic steels), irradiation experiments and materials inventory, and materials compatibility and hydrogen permeation studies. (DLC)

  2. Cytotoxicity of alloying elements and experimental titanium alloys by WST-1 and agar overlay tests.

    Science.gov (United States)

    Song, Yo-Han; Kim, Min-Kang; Park, Eun-Jin; Song, Ho-Jun; Anusavice, Kenneth J; Park, Yeong-Joon

    2014-09-01

    This study was performed to evaluate the biocompatibility of nine types of pure metals using 36 experimental prosthetic titanium-based alloys containing 5, 10, 15, and 20wt% of each substituted metal. The cell viabilities for pure metals on Ti alloys that contain these elements were compared with that of commercially pure (CP) Ti using the WST-1 test and agar overlay test. The ranking of pure metal cytotoxicity from most potent to least potent was: Co>Cu>In>Ag>Cr>Sn>Au>Pd>Pt>CP Ti. The cell viability ratios for pure Co, Cu, In, and Ag were 13.9±4.6%, 21.7±10.4%, 24.1±5.7%, and 24.8±6.0%, respectively, which were significantly lower than that for the control group (p<0.05). Pure Pd and Pt demonstrated good biocompatibility with cell viabilities of 93.8±9.6% and 97.2±7.1%, respectively. The Ti-5Pd alloy exhibited the highest cell viability (128.4±21.4%), which was greater than that of CP Ti. By alloying pure Co or Cu with Ti, the cell viabilities for the Ti-xCo and Ti-xCu alloys increased significantly up to 10wt% of the alloying element followed by a gradual decrease with a further increase in the concentration of the alloying element. Based on the agar overlay test, pure Ag, Co, Cr, Cu, and In were ranked as 'moderately cytotoxic', whereas all Ti alloys were ranked as 'noncytotoxic'. The cytotoxicity of pure Ag, Co, Cr, Cu, and In suggests a need for attention in alloy design. The cytotoxicity of alloying elements became more biocompatible when they were alloyed with titanium. However, the cytotoxicity of titanium alloys was observed when the concentration of the alloying element exceeded its respective allowable limit. The results obtained in this study can serve as a guide for the development of new Ti-based alloy systems. Copyright © 2014 Academy of Dental Materials. All rights reserved.

  3. Method for producing La/Ce/MM/Y base alloys, resulting alloys and battery electrodes

    Science.gov (United States)

    Gschneidner, Jr., Karl A.; Schmidt, Frederick A.

    2016-12-20

    A carbothermic reduction method is provided for reducing a La-, Ce-, MM-, and/or Y-containing oxide in the presence of carbon and a source of a reactant element comprising Si, Ge, Sn, Pb, As, Sb, Bi, and/or P to form an intermediate alloy material including a majority of La, Ce, MM, and/or Y and a minor amount of the reactant element. The intermediate material is useful as a master alloy for in making negative electrode materials for a metal hydride battery, as hydrogen storage alloys, as master alloy additive for addition to a melt of commercial Mg and Al alloys, steels, cast irons, and superalloys; or in reducing Sm.sub.2O.sub.3 to Sm metal for use in Sm--Co permanent magnets.

  4. Plasma surface alloying of titanium alloy for enhancing burn-resistant property

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ping-ze; XU Zhong; ZHANG Gao-hui; HE Zhi-yong; YAO Zheng-jun

    2006-01-01

    Conventional titanium alloy may be ignited and burnt under high temperature, high pressure and high gas flow velocity condition. In order to avoid this problem, burn-resistant alloying layers were made on the surface of Ti-6Al-4V and Ti-6.5Al-0.3Mo-1.5Zr-0.25Si titanium alloys by using double glow plasma surface alloying technology (DG Technology). Two typical burn-resistant layers Ti-Cr and Ti-Mo were made by DG plasma chromizing and DG plasma molybdenizing, respectively. Burn-resistant properties were tested by layer ignition method using 2 kW laser machine. Ignition experiments result reveals that the ignition temperature of alloyed layer with Mo and Cr concentration above 10% is about 200℃ higher than ignition temperature of Ti-6Al-4V substrate.

  5. Minor alloying behavior in bulk metallic glasses and high-entropy alloys

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The effect of minor alloying on several bulk metallic glasses and high-entropy al-loys was studied. It was found that minor Nb addition can optimize the interface structure between the W fiber and the Zr-based bulk metallic glass in the compos-ites,and improve the mechanical properties. Minor Y addition can destabilize the crystalline phases by inducing lattice distortion as a result to improve the glass-forming ability,and the lattice distortion energy is closely related to the effi-ciency of space filling of the competing crystalline phases. A long-period ordered structure can precipitate in the Mg-based bulk metallic glass by yttrium alloying. For the high-entropy alloys,solid solution can be formed by alloying,and its me-chanical properties can be comparable to most of the bulk metallic glasses.

  6. PRODUCTION OF FeAl NANOSTRUCTURED ALLOY BY MECHANICAL ALLOYING AND ITS MICROSTRUCTURAL CHARACTERIZATION

    Directory of Open Access Journals (Sweden)

    Roberto. A. Rodríguez-Díaz

    2013-12-01

    Full Text Available In this work, a Fe40Al alloy was produced by the mechanical alloying technique, from a mixture of elemental powders constituted by Fe and Al, using different milling times. The evolution of size and morphology of powders depending on the milling time was characterized by scanning electron microscopy. The X-Ray Diffraction technique was utilized in order to characterize the crystalline structure evolution depending on the milling time. The Fe40Al alloy with a body centered cubic crystal structure was formed at 20 h of milling time. Besides, this alloy acquired a disordered crystal structure with a Nano metric grain size. The Nano metric grain size of disordered Fe40Al alloy was decreased at the same time as the milling time transcurred, while its lattice parameter was increased.

  7. Method for producing La/Ce/MM/Y base alloys, resulting alloys and battery electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Gschneidner, Jr., Karl A.; Schmidt, Frederick A.

    2016-12-20

    A carbothermic reduction method is provided for reducing a La-, Ce-, MM-, and/or Y-containing oxide in the presence of carbon and a source of a reactant element comprising Si, Ge, Sn, Pb, As, Sb, Bi, and/or P to form an intermediate alloy material including a majority of La, Ce, MM, and/or Y and a minor amount of the reactant element. The intermediate material is useful as a master alloy for in making negative electrode materials for a metal hydride battery, as hydrogen storage alloys, as master alloy additive for addition to a melt of commercial Mg and Al alloys, steels, cast irons, and superalloys; or in reducing Sm.sub.2O.sub.3 to Sm metal for use in Sm--Co permanent magnets.

  8. Modification of the titanium alloy surface in electroexplosive alloying with boron carbide and subsequent electron-beam treatment

    Science.gov (United States)

    Gromov, Victor E.; Budovskikh, Evgeniy A.; Ivanov, Yurii F.; Bashchenko, Lyudmila P.; Wang, Xinli; Kobzareva, Tatyana Yu.; Semin, Alexander P.

    2015-10-01

    The modification of the VT6 titanium alloy surface in electroexplosion alloying with plasma being formed in titanium foil with a weighed powder of boron carbide with subsequent irradiation by a pulsed electron beam has been carried out. An electroexplosive alloying zone of a thickness up to 50 μm with a gradient structure is found to form. The subsequent electron-beam treatment of the alloying zone results in smoothing of the alloying surface and is accompanied by the formation of the multilayer structure with alternating layers of various alloying degree at a depth of 30 μm.

  9. Modification of the titanium alloy surface in electroexplosive alloying with boron carbide and subsequent electron-beam treatment

    Energy Technology Data Exchange (ETDEWEB)

    Gromov, Victor E., E-mail: gromov@physics.sibsiu.ru; Budovskikh, Evgeniy A., E-mail: budovskikh-ea@physics.sibsiu.ru; Bashchenko, Lyudmila P., E-mail: gromov@physics.sibsiu.ru; Kobzareva, Tatyana Yu., E-mail: gromov@physics.sibsiu.ru; Semin, Alexander P., E-mail: gromov@physics.sibsiu.ru [Siberian State Industrial University, Novokuznetsk, 654007 (Russian Federation); Ivanov, Yurii F., E-mail: yufi55@mail.ru [Institute of High Current Electronics SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk State University, Tomsk, 634050 (Russian Federation); Wang, Xinli, E-mail: wangxl520@hotmail.com [Northeastern University, Liaoning, Shenyang 110819 China (China)

    2015-10-27

    The modification of the VT6 titanium alloy surface in electroexplosion alloying with plasma being formed in titanium foil with a weighed powder of boron carbide with subsequent irradiation by a pulsed electron beam has been carried out. An electroexplosive alloying zone of a thickness up to 50 μm with a gradient structure is found to form. The subsequent electron-beam treatment of the alloying zone results in smoothing of the alloying surface and is accompanied by the formation of the multilayer structure with alternating layers of various alloying degree at a depth of 30 μm.

  10. The influence of alloy composition on residual stresses in heat treated aluminium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, J.S., E-mail: jeremy.robinson@ul.ie [Department of Mechanical, Aeronautical and Biomedical Engineering, University of Limerick (Ireland); Redington, W. [Materials and Surface Science Institute, University of Limerick (Ireland)

    2015-07-15

    The as quenched properties of eight different heat treatable aluminium alloys are related to residual stress magnitudes with the objective being to establish if there is a relationship between the residual stress and the as quenched alloy hardness and strength. Near surface residual stresses were assessed with X-ray diffraction using both the established sin{sup 2}ψ method and the more recent cos α technique. Through thickness residual stresses were also characterised using neutron diffraction. The alloys were chosen to encompass a wide range of strengths. The low to medium strength alloys were 6060 and 6082, medium to high strength 2618A, 2014A, 7075, 7010 and two variants of 7449, while the very high strength alloy was the powder metallurgy alloy N707. To assess the as quenched strength, dynamic hardness and tensile properties were determined from samples tested immediately after quenching to minimise the influence of precipitation hardening by natural aging. In addition, hot hardness measurements were made in situ on samples cooled to simulate quench paths. Within the experimental constraints of the investigation, the distribution of residual stress through the thickness was found to follow the same pattern for all the alloys investigated, varying from tensile in the interior to surface compression. The influence of alloy strength was manifested as a change in the observed residual stress magnitudes, and surface residual stresses were found to vary linearly with as quenched hardness and strength. - Highlights: • As quenched aluminium alloys contain high magnitude residual stresses. • Surface is compressive balance by a tensile core. • As quenched surface residual stress is linear function of alloy strength. • In situ hot hardness demonstrates rapid change in intrinsic hardness during rapid cooling.

  11. High-Strength Low-Alloy (HSLA) Mg-Zn-Ca Alloys with Excellent Biodegradation Performance

    Science.gov (United States)

    Hofstetter, J.; Becker, M.; Martinelli, E.; Weinberg, A. M.; Mingler, B.; Kilian, H.; Pogatscher, S.; Uggowitzer, P. J.; Löffler, J. F.

    2014-04-01

    This article deals with the development of fine-grained high-strength low-alloy (HSLA) magnesium alloys intended for use as biodegradable implant material. The alloys contain solely low amounts of Zn and Ca as alloying elements. We illustrate the development path starting from the high-Zn-containing ZX50 (MgZn5Ca0.25) alloy with conventional purity, to an ultrahigh-purity ZX50 modification, and further to the ultrahigh-purity Zn-lean alloy ZX10 (MgZn1Ca0.3). It is shown that alloys with high Zn-content are prone to biocorrosion in various environments, most probably because of the presence of the intermetallic phase Mg6Zn3Ca2. A reduction of the Zn content results in (Mg,Zn)2Ca phase formation. This phase is less noble than the Mg-matrix and therefore, in contrast to Mg6Zn3Ca2, does not act as cathodic site. A fine-grained microstructure is achieved by the controlled formation of fine and homogeneously distributed (Mg,Zn)2Ca precipitates, which influence dynamic recrystallization and grain growth during hot forming. Such design scheme is comparable to that of HSLA steels, where low amounts of alloying elements are intended to produce a very fine dispersion of particles to increase the material's strength by refining the grain size. Consequently our new, ultrapure ZX10 alloy exhibits high strength (yield strength R p = 240 MPa, ultimate tensile strength R m = 255 MPa) and simultaneously high ductility (elongation to fracture A = 27%), as well as low mechanical anisotropy. Because of the anodic nature of the (Mg,Zn)2Ca particles used in the HSLA concept, the in vivo degradation in a rat femur implantation study is very slow and homogeneous without clinically observable hydrogen evolution, making the ZX10 alloy a promising material for biodegradable implants.

  12. Toxoplasmose em primatas neotropicais: estudo retrospectivo de sete casos

    Directory of Open Access Journals (Sweden)

    Renata A. Casagrande

    2013-01-01

    Full Text Available A toxoplasmose é considerada uma doença parasitária fatal em primatas neotropicais. O objetivo deste trabalho foi descrever, através de um estudo retrospectivo, os casos de toxoplasmose em primatas neotropicais. No período de 1999-2009 foram realizados 86 exames anatomopatológicos em primatas e a toxoplasmose foi a enfermidade mais comum (7/86, relatando-se um caso em sagui-do-tufo-preto (Callithrix penicillata e seis em bugio-ruivo (Alouatta guariba. Dois animais foram encontrados mortos e cinco morreram em poucos dias. Os sinais clínicos mais frequentes foram apatia e anorexia (5/7, distensão abdominal (4/7 e febre (3/7. Na necropsia observou-se esplenomegalia (4/7, hemorragia do trato digestório, linfonodos e bexiga (4/7, pulmões avermelhados (3/7 e hepatomegalia (2/7. No exame histopatológico evidenciou-se hepatite (7/7, esplenite (3/7, miocardite (2/7, enterite (2/7, linfadenite (1/7 e sialite (1/7 necróticas e, pneumonia intersticial (4/7. Em fígado, pulmões, baço, coração, linfonodos e glândula salivar havia taquizoítos de Toxoplasma gondii que foram também detectados pelo exame de imuno-histoquímica anti-T. gondii em fígado, baço e pulmões (5/7. A toxoplasmose pode causar alta mortalidade em colônias de primatas neotropicais e representar mais uma ameaça à conversação dessas espécies em cativeiro. Sendo assim, medidas preventivas devem ser tomadas para evitar a contaminação desses animais.

  13. Atitude religiosa e sentido da vida: um estudo correlacional

    Directory of Open Access Journals (Sweden)

    Thiago Antônio Avellar de Aquino

    Full Text Available A presente pesquisa abordou o sentido da vida (Viktor Frankl e a atitude religiosa. Para a logoterapia, a religiosidade não significa necessariamente a opção por uma crença religiosa, mas pode ser uma das possíveis maneiras de o homem encontrar sentido para a vida. O objetivo deste estudo foi investigar a relação entre o sentido de vida e a atitude religiosa de forma transversal e correlacional. A amostra foi composta por 300 sujeitos de ambos os sexos, 37% homens e 63% mulheres, com idade média de 42 anos. Os instrumentos utilizados foram o Teste Propósito de Vida (PIL-Test, de James C. Crumbauch e Leonard T. Maholick, e a Escala de Atitude Religiosa/Espiritualidade, de Aquino. Os resultados apontam correlações positivas entre a atitude religiosa e a realização existencial, a atitude religiosa e a idade, o desespero existencial e o vazio existencial e a realização existencial e a idade, havendo também correlações negativas entre a atitude religiosa e o desespero existencial, a atitude religiosa e o vazio existencial, o desespero existencial e a realização existencial e o vazio existencial e a realização existencial. Concluiu-se que a atitude religiosa é uma forma de encontro de sentido de vida bem como um elemento de prevenção do vazio existencial e do desespero existencial.

  14. Apoio Matricial: um estudo bibliográfico

    Directory of Open Access Journals (Sweden)

    Alexandra Iglesias

    2014-09-01

    Full Text Available Este artigo constitui-se de um estudo de revisão bibliográfica a respeito do apoio matricial em saúde mental. Foi realizada uma busca nas bases de dados da Biblioteca Virtual da Saúde - Lilacs e SciELO - e do Google acadêmico, com as palavras-chave "apoio matricial em saúde mental" e/ou "matriciamento em saúde mental". Foram encontrados 14 artigos com as características desejadas, o que evidencia o número restrito de publicações sobre o tema. Os artigos foram analisados quanto a sua parte estrutural e metodológica, destacando a predominância absoluta do uso do método qualitativo e dos profissionais de saúde como população alvo das pesquisas. Em seguida, estes mesmos artigos foram analisados quanto a suas discussões teóricas. Ressalta-se, dentre outras questões, a importância do apoio matricial para potencialização das equipes da atenção básica no cuidado às pessoas em sofrimento psíquico. Contudo, ainda são muitas as confusões quanto à proposta do apoio matricial e as responsabilidades compartilhadas entre equipes de Referências e profissionais de saúde mental, o que apontam para a necessidade de capacitação destes profissionais, além de uma melhor articulação e organização da rede de cuidado em saúde mental.

  15. Citotoxicidade de soldas elétricas a ponto: estudo in vitro Cytotoxicity of electric spot welding: an in vitro study

    Directory of Open Access Journals (Sweden)

    Rogério Lacerda dos Santos

    2011-06-01

    Full Text Available OBJETIVO: o processo de solda envolve íons metálicos capazes de provocar lise celular. Diante disso, o objetivo deste estudo foi testar a hipótese de que existe citotoxicidade entre diferentes tipos de ligas (CrNi, TMA, NiTi utilizadas em Ortodontia, submetidas à solda elétrica a ponto. MÉTODOS: três tipos de ligas foram avaliados neste estudo. Foram confeccionados 36 corpos de prova, 6 para cada combinação entre os fios, divididos em 6 grupos - grupo AA (aço com aço, grupo AT (aço com TMA, grupo AN (aço com NiTi, grupo TT (TMA com TMA, grupo TN (TMA com NiTi e grupo NN (NiTi com NiTi - que foram submetidos à solda a ponto para avaliação quanto ao possível efeito citotóxico nos tecidos bucais. Previamente, os corpos de prova foram limpos com álcool isopropílico e esterilizados em luz ultravioleta. O ensaio de citotoxicidade foi realizado utilizando-se cultura de células (linhagem L929, fibroblastos de camundongos, submetida ao teste para células viáveis em vermelho neutro ("dye-uptake" no tempo de 24h. A análise de variância e comparação múltipla (ANOVA e teste de Tukey foram utilizados (p 0,05. Foi observada maior viabilidade celular no grupo TT, seguido dos grupos AT, TN, AA, NA e NN. CONCLUSÃO: pôde-se evidenciar que solda em fios de liga de NiTi causaram maior quantidade de lise celular. Soldas elétricas a ponto demonstraram pequena capacidade de causar lise celular.OBJECTIVE: The welding process involves metal ions capable of causing cell lysis. In view of this fact, the aim of this study was to test the hypothesis that cytotoxicity is present in different types of alloys (CrNi, TMA, NiTi commonly used in orthodontic practice when these alloys are subjected to electric spot welding. METHODS: Three types of alloys were evaluated in this study. Thirty-six test specimens were fabricated, 6 for each wire combination, and divided into 6 groups: Group SS (stainless steel, Group ST (steel with TMA, Group SN (steel

  16. The Origin of the Name "Onion's Fusible Alloy"

    Science.gov (United States)

    Jensen, William B.

    2010-01-01

    In response to a reader query, this article traces the history of fusible alloys, including Newton's metal, D'Arcet's metal, Rose's metal, Onion's fusible alloy, and Wood's metal. (Contains 1 table and 1 figure.)

  17. Measurement and analyses of molten Ni-Co alloy density

    Institute of Scientific and Technical Information of China (English)

    XIAO Feng; K. MUKAI; FANG Liang; FU Ya; YANG Ren-hui

    2006-01-01

    With the advent of powerful mathematical modeling techniques for material phenomena, there is renewed interest in reliable data for the density of the Ni-based superalloys. Up to now, there has been few report on the density of molten Ni-Co alloy.In order to obtain more accurate density data for molten Ni-Co alloy, the density of molten Ni-Co alloy was measured with a modified sessile drop method, and the accommodation of different atoms in molten Ni-Co alloy was analyzed. The density of alloy is found to decrease with increasing temperature and Co concentration in the alloy. The molar volume of molten Ni-Co alloy increases with increasing Co concentration. The molar volume of Ni-Co alloy determined shows a positive deviation from the linear molar volume, and the deviation of molar volume from ideal mixing increases with increasing Co concentration over the experimental concentration range.

  18. Recent progress on gas tungsten arc welding of vanadium alloys

    Energy Technology Data Exchange (ETDEWEB)

    King, J.F.; Grossbeck, M.L.; Goodwin, G.M.; Alexander, D.J. [Oak Ridge National Lab., TN (United States)

    1997-04-01

    This is a progress report on a continuing research project to acquire a fundamental understanding of the metallurgical processes in the welding of vanadium alloys. It also has the goal of developing techniques for welding structural vanadium alloys. The alloy V-4Cr-4Ti is used as a representative alloy of the group; it is also the prime candidate vanadium alloy for the U.S. Fusion Program at the present time. However, other alloys of this class were used in the research as necessary. The present work focuses on recent findings of hydrogen embrittlement found in vanadium alloy welds. It was concluded that the atmosphere in the inert gas glove box was insufficient for welding 6mm thick vanadium alloy plates.

  19. Investigation of the formability of aluminium alloys at elevated temperatures

    Science.gov (United States)

    Tisza, M.; Budai, D.; Kovács, P. Z.; Lukács, Zs

    2016-11-01

    Aluminium alloys are more and more widely applied in car body manufacturing. Increasing the formability of aluminium alloys are one of the most relevant tasks in todays’ research topics. In this paper, the focus will be on the investigation of the formability of aluminium alloys concerning those material grades that are more widely applied in the automotive industry including the 5xxx and 6xxx aluminium alloy series. Recently, besides the cold forming of aluminium sheets the forming of aluminium alloys at elevated temperatures became a hot research topic, too. In our experimental investigations, we mostly examined the EN AW 5754 and EN AW 6082 aluminium alloys at elevated temperatures. We analysed the effect of various material and process parameters (e.g. temperature, sheet thickness) on the formability of aluminium alloys with particular emphasis on the Forming Limit Diagrams at elevated temperatures in order to find the optimum forming conditions for these alloys.

  20. Density of Ni-Cr Alloy in the Mushy State

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The density of Ni-Cr alloy in the mushy state has been measured using the modified sessile drop method. The density of Ni-Cr alloy in the mushy state was found to decrease with increasing temperature and Cr concentration in alloy.The molar volume of Ni-Cr alloy in the mushy state therefore increases with increasing the Cr concentration in alloy.The ratio of the difference of density divided by the temperature difference between liquidus and solidus temperatures decreases with increasing Cr concentration. The density of the alloy increased with the precipitation of a solid phase in alloy during the solidification process. The temperature dependence of the density of alloy in the mushy state was not linear but biquadratic.

  1. A rapid stress-corrosion test for aluminum alloys

    Science.gov (United States)

    Helfrich, W. J.

    1968-01-01

    Stressed alloy specimens are immersed in a salt-dichromate solution at 60 degrees C. Because of the minimal general corrosion of these alloys in this solution, stress corrosion failures are detected by low-power microscopic examination.

  2. Wear resistant steels and casting alloys containing niobium carbide

    Energy Technology Data Exchange (ETDEWEB)

    Theisen, W.; Siebert, S.; Huth, S. [Lehrstuhl Werkstofftechnik, Ruhr-Univ. Bochum (Germany)

    2007-12-15

    Niobium, like titanium and vanadium, forms superhard MC carbides that remain relatively pure in technical alloys on account of their low solubility for other metallic alloying elements. However, because they have a greater hardness than the precipitated chromium carbides commonly used in wear-resistant alloys, they are suitable as alternative hard phases. This contribution deals with new wear-resistant steels and casting alloys containing niobium carbide. These include a secondary hardening hardfacing alloy, a composite casting alloy for wear applications at elevated temperatures, a white cast iron as well as two variants of a corrosion-resistant cold-work tool steel produced by melt metallurgy and by powder metallurgy. A heat-resistant casting alloy is also discussed. Based on equilibrium calculations the microstructures developing during production of the alloys are analysed, and the results are discussed with respect to important properties such as abrasive wear and corrosion resistance. (orig.)

  3. Production, Properties and Applications of Bulk Amorphous Alloys

    Institute of Scientific and Technical Information of China (English)

    Tao Zhang; Akihisa Inoue

    2000-01-01

    A review is given of recent work concerned with the production method, the characteristic properties(1) Bulk amorphous system; (2) Mechanical and magnetic properties of bulkamorphous alloys; (3)application of bulk amorphous alloys.

  4. Assessment of Al-Li Alloys for Cryotanks

    Science.gov (United States)

    Babel, Henry W.; Bozich, William; Farahmand, Bob; DeJesus, Ron; Sankaran, K. K.; Schwab, Dave; Tarkanian, Mike; Funk, Joan G. (Technical Monitor)

    2002-01-01

    This viewgraph presentation provides information on steps undertaken to determine the suitability of Aluminum and Lithium alloys in cryogenic tank construction. Major characteristics are offered for several different candidate alloys including reliability, weldability, flammability, and required thicknesses.

  5. Diffusion Barrier Coating System and Oxidation Behavior of Coated Alloys

    Institute of Scientific and Technical Information of China (English)

    T.NARITA

    2009-01-01

    @@ 1 Introduction Research into the formation of Re-based alloys is in progress in our laboratory to provide a diffusion barrier layer between heat-resistant alloys and Al reservoir layers, which assist in the formation and maintenance a protective Al2O3 scale for long periods. Coatings with a two-layered structure comprised of inner Re-based alloy layer and outer β-NiAl layer with or without Pt addition were successfully formed on various heat resistant alloys such as Ni-based singlecrystal superalloys, Ni-based heat resistant alloys, NiMo based alloy, Ni-Cr based alloy, and Fe-based alloys. The duplex layer coating proposed is generally termed a diffusion barrier coating system; DBC system.

  6. Advances of Titanium Alloys and Its Biological Surface Modification

    Institute of Scientific and Technical Information of China (English)

    XU Ke-wei; HUANG Ping

    2004-01-01

    This paper reviews the past, present and future of surface modification of titanium alloy from the point of view of preparation of hard tissue replacement implants. The development of titanium alloy is also described.

  7. Composite purification technology and mechanism of recycled aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    房文斌; 耿耀宏; 安阁英; 叶荣茂

    2002-01-01

    Iron-rich inclusions in aluminum alloys can be effectively removed by composite purification of sedimentation and filtration technology.The results show that the purposed method has no negative effects on aluminum alloys and obviously improve their mechanical properties.

  8. Diffusion bonding of Al7075 alloy to titanium aluminum vanadate alloy

    Science.gov (United States)

    Alhazaa, Abdulaziz Nasser

    The aluminum alloy (Al7075) and titanium alloy (Ti-6Al-4V) are used in a variety of applications in the aerospace industry. However, the high cost of Ti-6Al-4V alloy has been a major factor which has limited its use and therefore, the ability to join Al7075 alloy to Ti-6Al-4V alloy can provide a product that is less costly, but retains the high strength and light weight properties necessary for the transport industry. However, the large difference in the physical properties between these two alloys prevents the use of conventional joining techniques such as fusion welding to join these dissimilar alloys. Therefore, the diffusion bonding technique was used to join Al7075 alloy to Ti-6Al-4V alloy with the objective of minimizing microstructural changes of the two alloys during the bonding process. In this thesis, solid state and liquid phase bonding processes were undertaken. Solid state bonding was employed without interlayers and was successful at 510°C and 7 MPa. The bond interface showed an absence of the oxides due to the dissolution of oxygen into the titanium solution. Bonds made using copper interlayers at a temperature sufficient enough to form eutectic liquid formation between copper and aluminum were produced. The intermetallics theta(Al2Cu), S(Al2CuMg) and T(Al2Mg3Zn3) were identified at the aluminum interface while Cu3Ti2 intermetallic was identified at the titanium interface. Bonds made using tin based alloys interlayers and copper coatings were successful and gave the highest shear strength. The eutectic formation on the Al7075 alloy was responsible for joint formation at the aluminum interface while the formation of Sn3Ti5 intermetallic was responsible for the joint formation at titanium interface. The corrosion rate of the bonds decreased with increasing bonding time for joints made using the tin based interlayer in 3% NaCl solution. However, the presence of copper within the joint increased the corrosion rate of the bonds and this was attributed to

  9. Surface Features of Nanocrystalline Alloys

    Directory of Open Access Journals (Sweden)

    Marcel Miglierini

    2015-12-01

    Full Text Available Nanocrystalline alloys are prepared by controlled annealing of metallic glass precursors. The latter are obtained by rapid quenching of a melt on a rotating wheel. This process leads to structural deviation of the produced ribbons’ surfaces. Structural features of as-quenched and thermally annealed 57Fe81Mo8Cu1B10 ribbons were studied employing Conversion Electron Mössbauer Spectrometry (CEMS and Conversion X-ray Mössbauer Spectrometry (CXMS. Enrichment of the alloy’s composition in 57Fe helped in identification of surface crystallites that were formed even during the production process. Magnetite and bcc-Fe were found at the wheel side of the as-quenched ribbons whereas only bcc-Fe nanocrystals were uncovered at the opposite air side. Accelerated formation of bcc-Fe was observed in this side of the ribbons after annealing. The relative content of magnetite at the wheel side was almost stable in near surface areas (CEMS and in more deep subsurface regions (CXMS. It vanished completely after annealing at 550 °C. No magnetite was observed at the air side of the ribbons regardless the annealing temperature and/or depth of the scanned regions.

  10. [Study on biocompatibility of titanium alloys].

    Science.gov (United States)

    Kodama, T

    1989-06-01

    The biocompatibility of two different titanium alloys, Ti-6Al-4V ELI and Ti-5Al-2, 5Fe, and pure titanium were evaluated. The results were as follows: 1) Titanium alloys were implanted into the dorsal subcutaneous tissues of the Hartley guinea-pig for 12 weeks, immersed in calf serum or in Ringer's solution for 8 weeks. The surface changes of the titanium alloys were observed by SEM and the chemical composition was analyzed by XMA. No evident surface changes were found. 2) Three hundred mg, 200 mg and 100 mg of the powders of the tested materials were immersed in 2ml of Eagle's MEM, incubated for 1-7 days, 8-21 days and 22-70 days at 37 C degrees. The amount of metallic elements dissolved in the solutions was measured by ICP and AAS. The detected corrosion rates of V and Al contained in the solution, in which Ti-6Al-4V ELI 100 mg was immersed for 1-7 days, were 194.3 +/- 17.6 and 73.0 +/- 28, 1 pg/mg alloy/day, respectively. V was released more than Al. The amount of Ti was below the detectable limit. The solution Ti-5Al-2.5 Fe 100 mg immersed for 1-7 days contained 31.9 +/- 34.4 pg/mg alloy/day Fe and 25.7 +/- 6.3 pg/mg alloy/day Al. Only in the solution 300 mg immersed for 1-7 days was Ti detected at 1.4 pg/mg alloy/day. 3) By the bacterial mutation assay of Salmonella typhimurium TA 98, Salmonella typhimurium TA 100 and Escherichia coli WP2 uvrA, the solutions, in which the tested materials were immersed, were not found to be mutagenic. 4) By the UDS assay, the grain counts on autoradiography with the solutions, in which the tested materials were immersed, were not greater than the negative control. The results suggest an excellent corrosion resistance of the titanium alloys. Mutagenicity was negative by these mutation assays, indicating that the tested alloys and pure titanium are safe for humans and animals.

  11. DEVELOPMENT AND RESEARCH OF THE ECONOMIC ALLOY PARAMAGNETIC STEELS

    Directory of Open Access Journals (Sweden)

    A. V. Alifanov

    2016-01-01

    Full Text Available The alloys of Fe-Cr-Ni-C system for the purpose of development the economic alloy paramagnetic (not magnetic steels are investigated. A series of alloys are melted for this purpose, deformation is carried out and a structural state was studied.The area for the selection of the chemical composition of the economic alloy steels with stable paramagnetic properties is defined.

  12. POTENTIAL USE OF MAGNESIUM ALLOYS FOR THE AUTOMOTIVE INDUSTRY

    Directory of Open Access Journals (Sweden)

    Kudret KANDEMİR

    2003-01-01

    Full Text Available Recently, there is a high interest in using lightweight materials for automotive applications where weight reduction and improvement in comfort are needed. Magnesium alloys with excellent specific strength and stiffness properties can be comparable with steel and aluminum alloys for applications in the automotive industry. For this reason, the properties of magnesium alloys are in the focus of research. This study aims at reviewing and evaluating the prospects of magnesium alloys use and applications in the automotive industry.

  13. Alloy element redistribution during sintering of powder metallurgy steels

    OpenAIRE

    Tahir, Abdul Malik

    2014-01-01

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

  14. The Progress on Laser Surface Modification Techniques of Titanium Alloy

    Institute of Scientific and Technical Information of China (English)

    LIANG Cheng; PAN Lin; Al Ding-fei; TAO Xi-qi; XIA Chun-huai; SONG Yan

    2004-01-01

    Titanium alloy is widely used in aviation, national defence, automobile, medicine and other fields because of their advantages in lower density, corrosion resistance, and fatigue resistance etc. As titanium alloy is higher friction coefficients, weak wear resistance, bad high temperature oxidation resistance and lower biocompatibility, its applications are restricted. Using laser surface modification techniques can significantly improve the surface properties of titanium alloy. a review is given for progress on laser surface modification techniques of titanium alloy in this paper.

  15. Microstructure and Aging of Powder-Metallurgy Al Alloys

    Science.gov (United States)

    Blackburn, L. B.

    1987-01-01

    Report describes experimental study of thermal responses and aging behaviors of three new aluminum alloys. Alloys produced from rapidly solidified powders and contain 3.20 to 5.15 percent copper, 0.24 to 1.73 percent magnesium, 0.08 to 0.92 percent iron, and smaller amounts of manganese, nickel, titanium, silicon, and zinc. Peak hardness achieved at lower aging temperatures than with standard ingot-metallurgy alloys. Alloys of interest for automobile, aircraft, and aerospace applications.

  16. Evolution of Hydrogen Storage Alloys Prepared by Special Methods

    Institute of Scientific and Technical Information of China (English)

    Guo Hong; Zhang Ximin; Jing Hai; Li Chengdong; Xu Jun

    2004-01-01

    Microstructure characteristics and electrochemical properties of hydrogen storage alloys prepared by gas atomization, melt spinning and strip casting respectively were outlined.The advantages, disadvantages and research development of the above methods for preparing hydrogen storage alloys were explained.The strip casting is a new special means for preparing AB5 rare earth hydrogen storage alloys of high performance and low cost, and the study of the strip casting for preparing hydrogen storage alloys is presented specially.

  17. Technique of Aluminum Alloy Composite by Inversion Casting

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

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

  18. Shape-Memory-Alloy Actuator For Flight Controls

    Science.gov (United States)

    Barret, Chris

    1995-01-01

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

  19. Effects of chemical composition on the corrosion of dental alloys

    OpenAIRE

    GALO, Rodrigo; RIBEIRO, Ricardo Faria; RODRIGUES, Renata Cristina Silveira; Rocha, Luís Augusto; Mattos,Maria da Glória Chiarello de

    2012-01-01

    The aim of this study was to determine the effect of the oral environment on the corrosion of dental alloys with different compositions, using electrochemical methods. The corrosion rates were obtained from the current-potential curves and electrochemical impedance spectroscopy (EIS). The effect of artificial saliva on the corrosion of dental alloys was dependent on alloy composition. Dissolution of the ions occurred in all tested dental alloys and the results were strongly dependent on the g...

  20. Experience with ferrosilicoaluminum alloy during deoxidation of steel

    Directory of Open Access Journals (Sweden)

    A. Mekhtiyev

    2015-10-01

    Full Text Available The article describes the process of deoxidation quiet and low-alloyed steel alloy ferrosilicoaluminum complex in comparison the existing, and with steel deoxidation technology with conventional alloys - ferrosilicon and secondary aluminum. A comparative analysis of quality steel, non-metallic inclusions metallographic studies and studies of the mechanical properties of the resulting steel was done. On a large array of experimental steel proved cost-effectiveness and feasibility of ferrosilicoaluminum during deoxidation quiet and low-alloyed steel.

  1. Effect of Microstructure on the Performance of Corrosion Resistant Alloys

    OpenAIRE

    Kishan Roodbari, Marzieh

    2015-01-01

    Corrosion by pitting in aluminum alloys is a very complex process that can be affected by various factors such as chemical composition and microstructure of the alloys. The electrochemistry and distribution of second phases populating the alloy are the main factors that significantly influence the corrosion of aluminum alloys. The purpose of the present work is to contribute to a deeper understanding of how the chemical composition and microstructure affect the ability of an al...

  2. Microstructures and properties of aluminum die casting alloys

    Energy Technology Data Exchange (ETDEWEB)

    M. M. Makhlouf; D. Apelian; L. Wang

    1998-10-01

    This document provides descriptions of the microstructure of different aluminum die casting alloys and to relate the various microstructures to the alloy chemistry. It relates the microstructures of the alloys to their main engineering properties such as ultimate tensile strength, yield strength, elongation, fatigue life, impact resistance, wear resistance, hardness, thermal conductivity and electrical conductivity. Finally, it serves as a reference source for aluminum die casting alloys.

  3. Welding of Aluminum Alloys to Steels: An Overview

    Science.gov (United States)

    2013-08-01

    alloy /Ag interlayer/steel non-centered electron beam welded joints, Transaction of non- Ferrous Metals Society of China 21 (2011) 2592-2596. [53] K.-J...UNCLASSIFIED: Distribution Statement A. Approved for public release. 1 UNCLASSIFIED Welding of aluminum alloys to steels: an overview M. Mazar...different materials, iron-based alloys and aluminum-based alloys are among the most significant materials that are finding applications on the various

  4. Standard Specification for Nickel-Chromium-Molybdenum-Columbium Alloy (UNS N06625), Nickel-Chromium-Molybdenum-Silicon Alloy (UNS N06219), and Nickel-Chromium-Molybdenum-Tungsten Alloy (UNS N06650) Rod and Bar

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2014-01-01

    Standard Specification for Nickel-Chromium-Molybdenum-Columbium Alloy (UNS N06625), Nickel-Chromium-Molybdenum-Silicon Alloy (UNS N06219), and Nickel-Chromium-Molybdenum-Tungsten Alloy (UNS N06650) Rod and Bar

  5. Fermi surface effects in terbium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Burgardt, P.

    1976-10-01

    Work is reported which was conducted to test of the relation of the generalized susceptibility (and therefore, the ordering properties) for Tb to the Fermi energy of Tb. In order to properly analyze the data a simple theory was developed to account for the effects on band structure which accompany alloying and attendant lattice size changes. Using this simple theory, the alloys of Tb with Mg are understood as a combination of Fermi energy lowering and of lattice contraction. The tendency of Th to promote the ferromagnetic structure in Th is understood as a combination of the Fermi energy being raised and of the lattice being expanded. The theory was also useful in explaining the interesting behavior of the Tb with Yb alloys which upon preliminary analysis did not seem to follow the theoretical predictions. After consideration of the volume effect, indeed the Tb with Yb alloys showed promotion of the helical structure as predicted. The complicated behavior of the Tb with Yb alloys is a case where the volume and valence effects compete. Results show that the magnetic ordering properties of the rare earths are intimately related to the Fermi surface geometry through the generalized susceptibility.

  6. Explosive compaction of CuCr alloys

    Institute of Scientific and Technical Information of China (English)

    李金平; 罗守靖; 龚朝晖; 牛玮; 纪松

    2002-01-01

    The production of CuCr alloys utilizing explosive compaction was studied. Mixture powders of CuCr alloys placed in tubes with a dimension of d14.0mm×21.4mm can be compacted using explosive pads of 16.5mm or 22.5mm. Thicker pads of explosive make the compacts more porous. The effects of the ratio of me/mp, ratio of me/(mp+mt) and impact energy on the density of compacts were similar, they were chosen to control explosive compaction, respectively. When adequate value of the parameters me/mp, me/(mt+mp) and impact energy of unit area of tube was chosen, high density(7.858g/cm3), high hardness(HB189) and low conductance (13.6MS/m) of CuCr alloys could be made by explosive compaction. The general properties of CuCr alloys by explosive compaction are similar to those of CuCr alloys by traditional process.

  7. Complex precipitation pathways in multicomponent alloys

    Energy Technology Data Exchange (ETDEWEB)

    Clouet, Emmanuel; Nastar, Maylise [Service de Recherches de Metallurgie Physique, CEA/Saclay, 91191 Gif-sur-Yvette (France); Lae, Ludovic; Deschamps, Alexis [LTPCM/ENSEEG, UMR CNRS 5614, Domaine Universitaire, BP 75, 38402 St Martin d' Heres (France); Epicier, Thierry [Groupe d' Etudes de Metallurgie Physique et de Physique des Materiaux, UMR CNRS 5510, INSA, 69621 Villeurbanne (France); Lefebvre, Williams [Groupe de Physique des Materiaux, UMR CNRS 6634, Universite de Rouen, 76801 Saint Etienne du Rouvray (France)

    2006-07-01

    One usual way to strengthen a metal is to add alloying elements and to control the size and the density of the precipitates obtained. However, precipitation in multicomponent alloys can take complex pathways depending on the relative diffusivity of solute atoms and on the relative driving forces involved. In Al - Zr - Sc alloys, atomic simulations based on first-principle calculations combined with various complementary experimental approaches working at different scales reveal a strongly inhomogeneous structure of the precipitates: owing to the much faster diffusivity of Sc compared with Zr in the solid solution, and to the absence of Zr and Sc diffusion inside the precipitates, the precipitate core is mostly Sc-rich, whereas the external shell is Zr-rich. This explains previous observations of an enhanced nucleation rate in Al - Zr - Sc alloys compared with binary Al - Sc alloys, along with much higher resistance to Ostwald ripening, two features of the utmost importance in the field of light high-strength materials. (authors)

  8. A jumping shape memory alloy under heat.

    Science.gov (United States)

    Yang, Shuiyuan; Omori, Toshihiro; Wang, Cuiping; Liu, Yong; Nagasako, Makoto; Ruan, Jingjing; Kainuma, Ryosuke; Ishida, Kiyohito; Liu, Xingjun

    2016-02-16

    Shape memory alloys are typical temperature-sensitive metallic functional materials due to superelasticity and shape recovery characteristics. The conventional shape memory effect involves the formation and deformation of thermally induced martensite and its reverse transformation. The shape recovery process usually takes place over a temperature range, showing relatively low temperature-sensitivity. Here we report novel Cu-Al-Fe-Mn shape memory alloys. Their stress-strain and shape recovery behaviors are clearly different from the conventional shape memory alloys. In this study, although the Cu-12.2Al-4.3Fe-6.6Mn and Cu-12.9Al-3.8Fe-5.6Mn alloys possess predominantly L2(1) parent before deformation, the 2H martensite stress-induced from L2(1) parent could be retained after unloading. Furthermore, their shape recovery response is extremely temperature-sensitive, in which a giant residual strain of about 9% recovers instantly and completely during heating. At the same time, the phenomenon of the jumping of the sample occurs. It is originated from the instantaneous completion of the reverse transformation of the stabilized 2H martensite. This novel Cu-Al-Fe-Mn shape memory alloys have great potentials as new temperature-sensitive functional materials.

  9. The physical metallurgy of mechanically-alloyed, dispersion-strengthened Al-Li-Mg and Al-Li-Cu alloys

    Science.gov (United States)

    Gilman, P. S.

    1984-01-01

    Powder processing of Al-Li-Mg and Al-Li-Cu alloys by mechanical alloying (MA) is described, with a discussion of physical and mechanical properties of early experimental alloys of these compositions. The experimental samples were mechanically alloyed in a Szegvari attritor, extruded at 343 and 427 C, and some were solution-treated at 520 and 566 C and naturally, as well as artificially, aged at 170, 190, and 210 C for times of up to 1000 hours. All alloys exhibited maximum hardness after being aged at 170 C; lower hardness corresponds to the solution treatment at 566 C than to that at 520 C. A comparison with ingot metallurgy alloys of the same composition shows the MA material to be stronger and more ductile. It is also noted that properly aged MA alloys can develop a better combination of yield strength and notched toughness at lower alloying levels.

  10. Effects of micro-alloying with Sc and Mn on microstructure and mechanical properties of Al-Mg based alloys

    Institute of Scientific and Technical Information of China (English)

    CHEN Xian-ming; LUO Cheng-ping; PAN Qing-lin; YIN Zhi-ming

    2005-01-01

    An extensive investigation was made on the effects of micro-alloying with small amounts of Sc and Mn on the microstructure and mechanical properties of the Al-Mg based alloys. It is found that the micro-alloying can significantly enhance the tensile strength of the alloys, and eliminate the dendritic cast structure in it. Many fine,spherical and dispersive Al3Sc particles are found in the annealed Al-Mg-Mn-Sc alloys, which can strongly pin up dislocations and subgrain boundaries, thus strongly retarding the recrystallization of the alloys. The strengthening of the micro-alloyed Al-Mg alloys is attributed to the precipitation strengthening by the Al3Sc particles and to the substructure strengthening.

  11. STRUCTURE FORMATION OF ALLOYS ON IRON BASIS AFTER LASER ALLOYING

    Directory of Open Access Journals (Sweden)

    О. V. Diachenko

    2016-01-01

    Full Text Available The paper is devoted to investigations on influence of laser treatment regimes of gas-thermal and adhesive coatings from self-fluxing powders on iron basis and after melting with modifying plaster on their roughness and phase composition. One of mathematical planning methods that is a complete factor experiment method has been used for investigation of parameters’ influence on micro-geometry of coatings. The executed investigations have made it possible to observe a general regularity which does not depend on a type of alloying plaster: while increasing speed of laser beam relatively to treated part, beam diameter value of Ra parameter is becoming less. Decrease in height of surface irregularities in case of increasing laser beam speed is related with intensification of evaporation processes. An increase in beam diameter diminishes Ra parameter of the surface. This is due to the fact that decrease in power density occurs at high rate of beam defocusing. Overlapping coefficient does not exert a pronounced effect on Ra parameter of fused coatings. While increasing the speed of laser beam relatively to the part structure is transferred from dendrite into supersaturated one with carbide and boride precipitations. It has been established that technological parameters of laser treatment and particularly speed of laser beam influence on coating composition. While increasing the speed up to v5 = 5 × 10–3 m/s amount of chromium has become larger by 1.5-fold that resulted in increase of micro-hardness of the coating from 9.5–10.1 GPa up to 11.04–15.50 GPa.

  12. Mechanical behaviour of pressed and sintered titanium alloys obtained from master alloy addition powders.

    Science.gov (United States)

    Bolzoni, L; Esteban, P G; Ruiz-Navas, E M; Gordo, E

    2012-11-01

    The fabrication of the workhorse Ti-6Al-4V alloy and of the Ti-3Al-2.5V alloy was studied considering the master alloy addition variant of the blending elemental approach conventionally used for titanium powder metallurgy. The powders were characterised by means thermal analysis and X-ray diffraction and shaped by means of uniaxial pressing. The microstructural evolution with the sintering temperature (900-1400 °C) was evaluated by SEM and EDS was used to study the composition. XRD patterns as well as the density by Archimedes method were also obtained. The results indicate that master alloy addition is a suitable way to fabricate well developed titanium alloy but also to produce alloy with the desired composition, not available commercially. Density of 4.3 g/cm³ can be obtained where a temperature higher than 1200 °C is needed for the complete diffusion of the alloying elements. Flexural properties comparable to those specified for wrought Ti-6Al-4V medical devices are, generally, obtained.

  13. Enriched alloy layer on an Al-Cu alloy studied by cyclic voltammetry

    Science.gov (United States)

    García Vergara, S. J.; Blanco Pinzon, C. E.; Skeldon, P.

    2017-01-01

    The behaviour of enriched Al-0.7at.%Cu alloy is investigated using cyclic voltammetry. Enriched alloy layers at the interface between the alloy/oxide film were developed by alkaline etching at 5mAcm-2 in 0.1M sodium hydroxide solution at 298K, with the time of etching determining the extent of enrichment. Cyclic voltammograms were recorded at a scan rate of 10mV s-1 in naturally aerated 0.1M ammonium pentaborate solution at 298K. The current overshoot of the enriched alloys was different from that for non-enriched alloy. The latter material revealed the usual single peaks, which are very similar. In contrast, the overshoot comprised two or more components for the enriched alloys. The behaviour is suggested to be associated with the atomic bonding of aluminium in copper-rich and aluminium-rich regions of the enriched alloy layer, with influence on the activation potentials for oxidation of aluminium.

  14. Laser surface alloying fabricated porous coating on NiTi shape memory alloy

    Institute of Scientific and Technical Information of China (English)

    ZHANG Song; ZHANG Chun-hua; MAN Hau-chung; LIU Chang-sheng

    2007-01-01

    Laser surface alloying technique was applied to fabricate a metallic porous coating on a solid NiTi shape memory alloy. By laser surface alloying a 40%TiH2-60%NiTi powder mixture on the surface of NiTi alloy using optimized laser process parameters, a porous but crack-free NiTi layer can be fabricated on the NiTi substrate. The porous coating is metallurgically bonded to the substrate NiTi alloy. The pores are uniformly distributed and are interconnected with each other in the coating. An average pore size of less than 10 μm is achieved. The Ni content of the porous layer is much less than that of the original NiTi surface. The existence of the porous coating on the NiTi alloy causes a 37% reduction of the tensile strength and 55% reduction of the strain as compared with the NiTi alloy. Possible biomedical or other applications for this porous surface with good mechanical strength provided by the substrate are prospective.

  15. Oxidation of Alloy 600 and Alloy 690: Experimentally Accelerated Study in Hydrogenated Supercritical Water

    Science.gov (United States)

    Moss, Tyler; Cao, Guoping; Was, Gary S.

    2017-04-01

    The objective of this study is to determine whether the oxidation of Alloys 600 and 690 in supercritical water occurs by the same mechanism in subcritical water. Coupons of Alloys 690 and 600 were exposed to hydrogenated subcritical and supercritical water from 633 K to 673 K (360 °C to 400 °C) and the oxidation behavior was observed. By all measures of oxide character and behavior, the oxidation process is the same above and below the supercritical line. Similar oxide morphologies, structures, and chemistries were observed for each alloy across the critical point, indicating that the oxidation mechanism is the same in both subcritical and supercritical water. Oxidation results in a multi-layer oxide structure composed of particles of NiO and NiFe2O4 formed by precipitation on the outer surface and a chromium-rich inner oxide layer formed by diffusion of oxygen to the metal-oxide interface. The inner oxide on Alloy 600 is less chromium rich than that observed on Alloy 690 and is accompanied by preferential oxidation of grain boundaries. The inner oxide on Alloy 690 initially forms by internal oxidation before a protective layer of chromium-rich MO is formed with Cr2O3 at the metal-oxide interface. Grain boundaries in Alloy 690 act as fast diffusion paths for chromium that forms a protective Cr2O3 layer at the surface, preventing grain boundary oxidation from occurring.

  16. Formation and characterization of Al-Ti-Nb alloys by electron-beam surface alloying

    Science.gov (United States)

    Valkov, S.; Petrov, P.; Lazarova, R.; Bezdushnyi, R.; Dechev, D.

    2016-12-01

    The combination of attractive mechanical properties, light weight and resistance to corrosion makes Ti-Al based alloys applicable in many industrial branches, like aircraft and automotive industries etc. It is known that the incorporation of Nb improves the high temperature performance and mechanical properties. In the present study on Al substrate Ti and Nb layers were deposited by DC (Direct Current) magnetron sputtering, followed by electron-beam alloying with scanning electron beam. It was chosen two speeds of the specimen motion during the alloying process: V1 = 0.5 cm/s and V2 = 1 cm/s. The alloying process was realized in circular sweep mode in order to maintain the melt pool further. The obtained results demonstrate a formation of (Ti,Nb)Al3 fractions randomly distributed in biphasic structure of intermetallic (Ti,Nb)Al3 particles, dispersed in α-Al solid solution. The evaluated (Ti,Nb)Al3 lattice parameters are independent of the speed of the specimen motion and therefore the alloying speed does not affect the lattice parameters and thus, does not form additional residual stresses, strains etc. It was found that lower velocity of the specimen motion during the alloying process develops more homogeneous structures. The metallographic analyses demonstrate a formation of surface alloys with very high hardness. Our results demonstrate maximal values of 775 HV [kg/cm2] and average hardness of 673 HV [kg/cm2].

  17. Oxidation of Alloy 600 and Alloy 690: Experimentally Accelerated Study in Hydrogenated Supercritical Water

    Science.gov (United States)

    Moss, Tyler; Cao, Guoping; Was, Gary S.

    2017-02-01

    The objective of this study is to determine whether the oxidation of Alloys 600 and 690 in supercritical water occurs by the same mechanism in subcritical water. Coupons of Alloys 690 and 600 were exposed to hydrogenated subcritical and supercritical water from 633 K to 673 K (360 °C to 400 °C) and the oxidation behavior was observed. By all measures of oxide character and behavior, the oxidation process is the same above and below the supercritical line. Similar oxide morphologies, structures, and chemistries were observed for each alloy across the critical point, indicating that the oxidation mechanism is the same in both subcritical and supercritical water. Oxidation results in a multi-layer oxide structure composed of particles of NiO and NiFe2O4 formed by precipitation on the outer surface and a chromium-rich inner oxide layer formed by diffusion of oxygen to the metal-oxide interface. The inner oxide on Alloy 600 is less chromium rich than that observed on Alloy 690 and is accompanied by preferential oxidation of grain boundaries. The inner oxide on Alloy 690 initially forms by internal oxidation before a protective layer of chromium-rich MO is formed with Cr2O3 at the metal-oxide interface. Grain boundaries in Alloy 690 act as fast diffusion paths for chromium that forms a protective Cr2O3 layer at the surface, preventing grain boundary oxidation from occurring.

  18. 21 CFR 872.3710 - Base metal alloy.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Base metal alloy. 872.3710 Section 872.3710 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3710 Base metal alloy. (a) Identification. A base metal alloy is a device composed primarily of base metals, such as nickel, chromium, or cobalt, that...

  19. 21 CFR 872.3080 - Mercury and alloy dispenser.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Mercury and alloy dispenser. 872.3080 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3080 Mercury and alloy dispenser. (a) Identification. A mercury and alloy dispenser is a device with a spring-activated valve intended to measure...

  20. 21 CFR 872.3060 - Noble metal alloy.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Noble metal alloy. 872.3060 Section 872.3060 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3060 Noble metal alloy. (a) Identification. A noble metal alloy is a device composed primarily of noble metals, such as gold, palladium, platinum, or silver,...

  1. Investigation of joining techniques for advanced austenitic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Lundin, C.D.; Qiao, C.Y.P.; Kikuchi, Y.; Shi, C.; Gill, T.P.S.

    1991-05-01

    Modified Alloys 316 and 800H, designed for high temperature service, have been developed at Oak Ridge National Laboratory. Assessment of the weldability of the advanced austenitic alloys has been conducted at the University of Tennessee. Four aspects of weldability of the advanced austenitic alloys were included in the investigation.

  2. Development and application of titanium alloy casting technology in China

    Institute of Scientific and Technical Information of China (English)

    NAN Hai; XIE Cheng-mu; ZHAO Jia-qi

    2005-01-01

    The development and research of titanium cast alloy and its casting technology, especially its application inaeronautical industry in China are presented. The technology of molding, melting and casting of titanium alloy, casting quality control are introduced. The existing problems and development trend in titanium alloy casting technology are also discussed.

  3. Residual stress state in titanium alloy remelted using GTAW method

    Directory of Open Access Journals (Sweden)

    A. Dudek

    2009-04-01

    Full Text Available Test materials comprised two-phase titanium alloy Ti6Al4V (Grade5. The surface of the tested alloy was remelted by means of TIG welding method using variable current-voltage parameters. The investigations aimed to determine surface geometry and residual stresses in the remelted surface layer in the investigated alloy.

  4. Corrosion wear fracture of new {beta} biomedical titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Niinomi, M.; Fukunaga, K.-I. [Toyohashi Univ. of Technol. (Japan). Dept. of Production Syst. Eng.; Kuroda, D.; Morinaga, M.; Kato, Y.; Yashiro, T.; Suzuki, A.

    1999-05-15

    Metallic materials such as stainless steel, Co-Cr alloy, pure titanium and titanium alloys have been used for surgical implant materials. The {alpha} + {beta} type titanium alloy such as Ti-6Al-4V ELI has been most widely used as an implant material for artificial hip joint and dental implant because of its high strength and excellent corrosion resistance. Toxicity of alloying elements in conventional biomedical titanium alloys like Al and V, and the high modulus of elasticity of these alloy as compared to that of bone have been, however, pointed out [1,2]. New {beta} type titanium alloys composed of non-toxic elements like Nb, Ta, Zr, Mo and Sn with lower moduli of elasticity, greater strength and greater corrosion resistance were, therefore, designed in this study. The friction wear properties of titanium alloys are, however, low as compared to those of other conventional metallic implant materials such as stainless steels and Co-Cr alloy. Tensile tests and friction wear tests in Ringer`s solution were conducted in order to investigate the mechanical properties of designed alloys. The friction wear characteristics of designed alloys and typical conventional biomedical titanium alloys were evaluated using a pin-on-disk type friction wear testing system and measuring the weight loss and width of groove of the specimen. (orig.) 8 refs.

  5. Foaming behaviour of Al-Si-Cu-Mg alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kim, A. [Kongju National University (Korea). Dept. of Mechanical Engineering; Cho, S.S. [Chungnam National University, Daejeon (Korea). School of Materials Engineering; Lee, H.J. [Hanbat National University, Daejeon (Korea). Dept. of Building Service Engineering

    2004-12-15

    The powder metallurgical route was utilised to obtain the Al-5Si-4Cu-4Mg (alloy 544) and Al-3Si-2Cu-2Mg (alloy 322) foams. Various steps such as centrifugal atomisation, mixing alloy powder and foaming agent (1 wt-%TiH{sub 2}), cold compaction of mixture, hot extrusion and foaming in a preheated furnace were performed. Foaming behaviour of the alloys was investigated by digital microscopy, image analysis, scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) mapping in this study. It was found that alloy 544 takes a shorter period of time to initiate pore nucleation than alloy 322. Alloy 544 had a higher pore growth rate than alloy 322 at the same pre-set furnace temperature. In both alloys, crack-like pore nucleation occurred between aluminium alloy powders elongated in a direction parallel to the extrusion direction. Both alloys showed the same foaming sequence of crack-like pore nucleation, spherical pore growth, coalescence of neighbouring pores and collapse of pores adjacent to the free surface of specimen. The time required to start pore nucleation decreased with the increase of foaming temperature. The cell walls of both alloys consisted of {alpha}-Al phase and eutectic phase. (author)

  6. New development of anodizing process of magnesium alloys

    Institute of Scientific and Technical Information of China (English)

    BAI Li-qun; LI Di

    2004-01-01

    Magnesium alloy, a kind of environment-friendly material with promising and excellent properties, is a good choice for a number of applications. The research and development of anodizing on magnesium alloys and its application situation are reviewed, and the anodizing development trend on magnesium alloys is summarized.

  7. Progress of Palladium Alloy Membranes in Hydrogen Energy

    Institute of Scientific and Technical Information of China (English)

    MA Guang; LI Jin; LI Yin'e; SUN Xiaoliang; CAO Qigao; JIA Zhihua

    2012-01-01

    Palladium and palladium alloy membranes have attracted wide attention in hydrogen permeation areas for their excellent permeability,perm-selectivity and thermal stability.This paper review the principle of hydrogen permeation,type of alloys and the fabrication methods.At last,the progress and achievements on palladium alloy membranes by Northwest Institute for Non-Ferrous Metal Research are emphasized.

  8. Microstructure and properties of modified and conventional 718 alloys

    Institute of Scientific and Technical Information of China (English)

    LIU Fang; SUN Wen-ru; DU Jin-hui; DONG Jian-xin; GUO Shou-ren; YANG Hong-cai; HU Zhuang-qi

    2006-01-01

    Continuing the effort to redesign IN718 alloy in order to provide microstructural and mechanical stability beyond 650 ℃, IN718 alloy was modified by increasing the Al, P and B contents, and the microstructure and mechanical properties of the modified alloy were compared with those of the conventional alloy by SEM and TEM. The precipitation of the grain boundaries of the two alloys is different. The Cr-rich phase, Laves phase and α-Cr phase are easily observed in the modified alloy. The γ″ and γ′ phases in the modified alloy are precipitated in a "compact form". The tensile strengths of the modified alloy at room temperature and 680 ℃ are obviously higher than those of the conventional one. The impact energy of the modified alloy is only about half of that of the conventional alloy. Ageing at 680 ℃ up to 1 000 h lowers the tensile properties and impact energy of both the conventional and modified 718 alloys, except increasing the ductility at 680 ℃. It is concluded that the modified alloy is more stable than the conventional one.

  9. NEW DEVELOPMENT IN DOUBLE GLOW SURFACE ALLOYING TECHNOLOGY

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Several kinds of special alloys are produced on the surfaces of iron and steels by using double glow surface alloying technology. Surface Ni-Cr-Mo-Nb alloy,surface precipitation hardening high speed steel and surface precipitation hardening stainless steel are introduced.

  10. Method of making quasicrystal alloy powder, protective coatings and articles

    Science.gov (United States)

    Shield, J.E.; Goldman, A.I.; Anderson, I.E.; Ellis, T.W.; McCallum, R.W.; Sordelet, D.J.

    1995-07-18

    A method of making quasicrystalline alloy particulates is disclosed wherein an alloy is superheated and the melt is atomized to form generally spherical alloy particulates free of mechanical fracture and exhibiting a predominantly quasicrystalline in the atomized condition structure. The particulates can be plasma sprayed to form a coating or consolidated to form an article of manufacture. 3 figs.

  11. Influence of finishing on the electrochemical properties of dental alloys.

    Science.gov (United States)

    Kaneko, T; Hattori, M; Hasegawa, K; Yoshinari, M; Kawada, E; Oda, Y

    2000-05-01

    Dental alloy surface finishing procedures of may influence their electrochemical behavior, which is used to evaluate their corrosion resistance. We examined the polarization resistance and potentiodynamic polarization profile of the precious-metal alloys, Type 4 gold alloy and silver-palladium alloy, and the base-metal alloys, nickel-chromium alloy, cobalt-chromium alloy, and CP-titanium. Three types of finishing procedure were examined: mirror-finishing using 0.05 micron alumina particles, polishing using #600 abrasive paper and sandblasting. Dissolution of the alloy elements in 0.9% NaCl solution was also measured and compared with the electrochemical evaluation. The corrosion resistance of the dental alloys was found to relate to finishing as follows: The polarization resistance and potentiodynamic polarization behavior revealed that the corrosion resistance improved in the order of sandblasting, #600-abrasive-paper polishing, and mirror-finishing. While the corrosion potential, critical current density and passive current density varied depending on the type of finishing, the transpassive potential remained unchanged. The influence of finishing on the corrosion resistance of precious-metal alloys was less significant than on that of base-metal alloys. A mirror-finishing specimen was recommended for use in evaluation of the corrosion resistance of various dental alloys.

  12. Film induced intergranular cracking of binary noble alloys

    Energy Technology Data Exchange (ETDEWEB)

    Friedersdorf, F. [Bureau of Mines, Albany, OR (United States); Sieradzki, K. [Arizona State Univ., Tempe, AZ (United States)

    1995-10-01

    Dealloying of a binary noble alloy produces a porous layer rich in the more noble element. Application of a tensile load may initiate a brittle intergranular crack in the dealloyed layer that advances into the unattached material. The relationships between the dealloying potential, dealloyed layer thickness and alloy susceptibility to film induced intergranular cracking have been studied. Ag-Au alloys were studied.

  13. Nanostructured Platinum Alloys for Use as Catalyst Materials

    Science.gov (United States)

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

    2015-01-01

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

  14. O Instituto de Estudos Avançados da USP

    Directory of Open Access Journals (Sweden)

    João Steiner

    2004-04-01

    Full Text Available COMENTA-SE a missão especial do Instituto de Estudos Avançados da USP a abrangente agenda de debates sobre problemas mundiais, nacionais e institucionais. A sobrevivência da biosfera do Planeta Terra está ameaçada pelas mudanças globais induzidas pela atividade humana. A par disto, as relações internacionais estão, hoje, marcadas pelo unilateralismo político e protecionismo comercial dos paises desenvolvidos. A inserção do Brasil neste mundo complexo traz no se bojo extraordinários desafios políticos e comerciais. No cenário nacional ressalta-se a Política de Ciência e Tecnologia com seu sucesso no que diz respeito à pós-graduação e produção científica a par do insucesso no uso do conhecimento e falta de inovação que ameaçam nossa competitividade internacional, desenvolvimento econômico e bem-estar social. Conclui-se chamando a atenção para a grande responsabilidade da USP e do IEA no debate dos problemas nacionais e internacionais.THE SPECIAL mission of the University of São Paulo's Institute of Advanced Studies is here outlined, with focus on a broad agenda involving global, national and institutional problems. The survival of the biosphere of the Planet Earth is endangered by global changes caused by human activities. In addition, the international environment is poisoned by the political unilateralism and commercial protectionism of the developed countries. The role of Brazil in this complex world holds extraordinary political and commercial challenges. Our national Science and Technology Policy has been successful in terms of postgraduate human resources and scientific production, but has lagged behind in applying knowledge and promoting technological innovation, thus endangering our international competitiveness, economical development and social welfare. The University of São Paulo and its Institute of Advanced Studies have great responsibilities in the discussion of national as well as international

  15. Eletrocardiografia computadorizada em cães: estudo comparativo

    Directory of Open Access Journals (Sweden)

    Lídia S. Oliveira

    2013-07-01

    Full Text Available O método de eletrocardiografia computadorizada (ECG-C vem sendo crescentemente difundido na medicina veterinária, havendo atualmente diversas marcas e modelos de eletrocardiógrafos disponíveis no mercado. Diante da possibilidade de diferenças na sensibilidade e na reprodutibilidade das medidas obtidas nos traçados, o presente estudo teve como objetivo comparar os parâmetros eletrocardiográficos de cães, obtidos por dois sistemas. Foram avaliados dois diferentes softwares computadorizados, o Wincardio Micromed® (WIN e o modelo TEB ECGPC® (TEB. Quarenta e dois cães hígidos, de diferentes raças (Cocker Spaniel, Daschund, Labrador, Pinscher, Pit Bull Terrier Poodle, Schnauzer, Shit Tzu, Yorkshire e sem raça definida, machos e fêmeas e com idade entre 4 meses e 16 anos foram agrupados segundo o peso e examinados pelos dois sistemas. As medidas eletrocardiográficas dos diferentes traçados foram analisadas na derivação DII. Os resultados indicaram que o sistema TEB apresentou maior sensibilidade na obtenção das medidas de duração da onda P e do complexo QRS, enquanto o sistema WIN foi mais sensível para determinar as medidas de amplitude dos mesmos parâmetros. Os animais de maior porte (26-37kg apresentaram maior variância nas medidas de duração e amplitude de onda P e duração do complexo QRS em comparação aos cães de médio (14-25kg e pequeno (1-13kg porte. O achado de diferenças entre os sistemas testados deve ser levado em consideração ao se empregar os diversos equipamentos para diagnóstico por meio de ECG-C na rotina clínica, de modo a evitarem-se divergências na interpretação dos exames entre diferentes prestadores de serviços veterinários.

  16. Estudo in vitro da abrasividade de dentifrícios

    Directory of Open Access Journals (Sweden)

    ANDRADE JUNIOR Antonio Carlos Canabarro

    1998-01-01

    Full Text Available O objetivo do presente estudo é avaliar a abrasividade de 15 dentifrícios, utilizando o aparelho Einlehner AT 1000. Uma solução contendo 50 g de cada creme dental mais 800 ml de água destilada era colocada no referido aparelho, que promovia 174.000 rotações da haste metálica, com um cilindro descartável de borracha, sobre uma tela de cobre pesada previamente (P1, por 100 minutos. Com o término da operação, a tela era lavada, seca e novamente pesada (P2. Através da equação: (P1-P2 ÷ 3,07 x 10-4 encontrava-se o número de gramas/metro2. Cada dentifrício foi testado 3 vezes e o valor final apresentado é a média dos 3 testes. Adicionalmente foram investigados o pH e o teor de sólidos das diferentes marcas. Os resultados mostraram que os dentifrícios possuem uma grande variação no grau de abrasão. As 3 marcas mais abrasivas foram: Close Up com flúor, Colgate Antitártaro e Oral B Dentes e Gengivas, as duas primeiras com dióxido de silício. As 3 marcas menos abrasivas foram: Colgate M.F.P. com cálcio, Gessy com flúor e Signal com flúor, todas com carbonato de cálcio. Os dentifrícios Close Up com flúor, Kolynos Ação Total e Oral B Dentes e Gengivas apresentaram um pH abaixo de 7, que pode indicar um possível efeito erosivo, associado à abrasão. Novas pesquisas são necessárias para comparar esses resultados com cremes dentais internacionais.

  17. Magnesium alloy AZ63A reinforcement by alloying with gallium and using high-disperse ZrO2 particles

    Directory of Open Access Journals (Sweden)

    J. Khokhlova

    2016-12-01

    Full Text Available The aim of this work was to obtain an experimental magnesium alloy by remelting standard AZ63A alloy with addition of gallium ligatures and ZrO2 particles. This allowed reinforcement of alloy and increase its hardness and Young's modulus. The chemical analysis of this alloy shows two types of structures which are evenly distributed in volume. Thus we can conclude that reinforcing effect is the result of formation of intermetallic phase Mg5-Ga2.

  18. Electrocatalysts having platium monolayers on palladium, palladium alloy, and gold alloy core-shell nanoparticles, and uses thereof

    Energy Technology Data Exchange (ETDEWEB)

    Adzic, Radoslav (Setauket, NY); Mo, Yibo (Naperville, IL); Vukmirovic, Miomir (Port Jefferson Station, NY); Zhang, Junliang (Rochester, NY)

    2010-12-21

    The invention relates to platinum-coated particles useful as fuel cell electrocatalysts. The particles are composed of a noble metal or metal alloy core at least partially encapsulated by an atomically thin surface layer of platinum atoms. The invention particularly relates to such particles having a palladium, palladium alloy, gold alloy, or rhenium alloy core encapsulated by an atomic monolayer of platinum. In other embodiments, the invention relates to fuel cells containing these electrocatalysts and methods for generating electrical energy therefrom.

  19. Effects of alloy composition in alleviating embrittlement problems associated with the tantalum alloy T-111

    Science.gov (United States)

    Stephens, J. R.

    1975-01-01

    The causes of aging embrittlement in T-111 (Ta-8W-2Hf) and the effect of alloy modification were investigated. Results show that T-111 possesses a critical combination of tungsten and hafnium that leads to loss in ductility at -196 C after aging near 1040 C. It was found that this occurs because tungsten enhances hafnium segregation to grain boundaries, which also leads to increased susceptibility to hydrogen embrittlement. Aging embrittlement was not observed in tantalum alloys with reduced tungsten or hafnium contents; most of the alloys studied have lower strengths than T-111 and exhibit susceptibility to hydrogen embrittlement.

  20. XAFS Study on Solid State Amorphization of Alloys by Mechanical Alloying

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Structural evolution of alloys by ball-milling during solid stateamorphization were studied by means of XAFS technique. The first one is amorphization process of Fe and B powder mixtures by mechanical alloying (MA), and the second one is amorphization process of ordered B2 CoZr intermetallic compound by mechanical milling (MM). The mixing process of Fe and B and disintegration process of ordered B2 CoZr intermetallic compound crystal were observed clearly in atomic level by XAFS method. The micro-mechanism of amorphization process of alloy by ball-milling was discussed.

  1. Non-alloyed Ni3Al based alloys – preparation and evaluation of mechanical properties

    Directory of Open Access Journals (Sweden)

    J. Malcharcziková

    2013-07-01

    Full Text Available The paper reports on the fabrication and mechanical properties of Ni3Al based alloy, which represents the most frequently used basic composition of nickel based intermetallic alloys for high temperature applications. The structure of the alloy was controlled through directional solidification. The samples had a multi-phase microstructure. The directionally solidified specimens were subjected to tensile tests with concurrent measurement of acoustic emission (AE. The specimens exhibited considerable room temperature ductility before fracture. During tensile testing an intensive AE was observed.

  2. Separation of magnetic phases in alloys

    Energy Technology Data Exchange (ETDEWEB)

    Takacs, J. [Department of Engineering Science, University of Oxford, 5. Pound Close, Yarnton, Oxon OX5 1QG, Oxford (United Kingdom)], E-mail: jenotakacs@aol.com; Meszaros, I. [Department of Materials Science and Technology, Budapest University of Technology and Economics, Budapest (Hungary)

    2008-09-01

    In this paper we present a study of the separation of phases in multi-phase alloys. The proposed technique is based on the hyperbolic model of magnetization. By using this model it is possible to decompose the magnetic phases of alloys and determine their magnetic properties separately. Experimental verification was carried out on a transformer-like setup, constructed from layered samples representing the various magnetic phases. The samples were constructed from elements of strongly different magnetic properties. The results given by the model are in an excellent agreement with the experimental results, giving justification for the proposed method of decomposition. The proposed method is the first step towards the recognition and the separation of magnetic constituencies of different magnetic properties in an alloy by analytical means.

  3. High temperature alloys: their exploitable potential

    Energy Technology Data Exchange (ETDEWEB)

    Marriott, J.B.; Merz, M.; Nihoul, J.; Ward, J. (eds.) (Commission of the European Communities, Petten (Netherlands). Joint Nuclear Research Center; NET-TEAM, Garching (DE))

    1987-01-01

    This book is the proceedings of a conference dealing with fundamental and technical aspects of the applications of high temperature alloys. It is split into five sections which cover the opening session of the conference and four further sessions covering: the theoretical and practical limits for HT alloys; the potential for development in alloys and processing; engineering considerations; the future outlook. The different sessions each included a number of invited papers followed by a series of posters and were concluded by a presentation of a 'synthesis' by a session rapporteur and general discussion. This structure is retained in the proceedings, including the discussion points in those cases where the authors have provided written answers to the questions raised. This book will be of interest to metallurgists, materials scientists, physicists and research workers in high temperature materials.

  4. The Mg impurity in nitride alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zvanut, M. E.; Willoughby, W. R.; Sunay, U. R. [Department of Physics, University of Alabama at Birmingham, Birmingham AL (United States); Koleske, D. D.; Allerman, A. A. [Sandia National Laboratory, Albuquerque NM (United States); Wang, Ke; Araki, Tsutomu [Department of Photonics, Ritsumeikan University, Kusatsu, Shiga (Japan); Nanishi, Yasushi [Department of Photonics, Ritsumeikan University, Kusatsu, Shiga, Japan and WCU Program, Department of Materials Science and Engineering, Seoul National University, Seoul (Korea, Republic of)

    2014-02-21

    Although several magnetic resonance studies address the Mg acceptor in GaN, there are few reports on Mg doping in the alloys, where hole production depends strongly on the Al or In content. Our electron paramagnetic resonance (EPR) measurements of the p-type alloys suggest that the Mg impurity retains the axial symmetry, characteristic of a p-type dopant in both alloys; however, In and Al produce additional, different characteristics of the acceptor. In InGaN, the behavior is consistent with a lowering of the acceptor level and increasing hole density as In concentration increases. For AlGaN, the amount of neutral Mg decreases with increasing Al content, which is attributed to different kinetics of hydrogen diffusion thought to occur in samples with higher Al mole fraction.

  5. Electrochemical formation of holmium-cobalt alloys

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The electrochemical formation processes of holmium-cobalt alloys on cobalt cathode in molten HoC13-KC1 wereinvestigated by cyclic voltammetry and open current potential-time curve after potentiostatic electrolysis. The structure ofHo-Co alloys' films deposited on cobalt electrode by potentiostatic electrolysis was characterized by X-ray diffraction. Thestandard Gibbs free energies of formation for the intermetallic compounds of Ho and Co were determined. The diffusioncoefficient and diffusion activation energy of Ho atom in the alloy phase were calculated to be 10-10-10-11 cm2/s and 96.0kJ/mol, respectively, from the current-time curve at potential step.

  6. Hydrogenation properties of Mg-Al alloys

    DEFF Research Database (Denmark)

    Andreasen, Anders

    2008-01-01

    In this paper the properties of Mg-Al alloys in relation to hydrogen storage are reviewed. The main topics of this paper are materials preparation, hydrogen capacity, thermodynamics of hydride formation, and the kinetics of hydride formation and decomposition. Hydrogenation of Mg-Al leads...... to disproportionation with the formation of magnesium hydride and metallic aluminum as the final product. Experimental evidence renders this process reversible. It is observed that the enthalpy of hydride formation of magnesium is lowered upon alloying with Al due to a slightly endothermic disproportionation reaction....... Further, it is found that the kinetics of hydrogenation, as well dehydrogenation, may be significantly improved by alloying compared to pure Mg. The expense of these improvements of the hydrogenation/dehydrogenation properties is a lower gravimetric hydrogen density in the hydrogenated product, (C) 2008...

  7. Microstructure and Slip Character in Titanium Alloys

    Directory of Open Access Journals (Sweden)

    D. Banerjee

    1986-04-01

    Full Text Available Influence of microstructures in titanium alloys on the basic parameters of deformation behaviour such as slip character, slip length and slip intensity have been explored. Commercial titanium alloys contain the hexagonal close packed (alpha and body centred cubic (bita phases. Slip in these individual phases is shown to be dependent on the nature of alloying elements through their effect on phase stability as related to decomposition into ordered or w structures. When alpha and bita coexist, their relative crystallographic orientations, size, shape and volume fraction, control the nature of slip. For a given composition, structure may be manipulated through appropriate thermomechanical treatment to obtain the desired deformation behaviour and therefore fracture mode.

  8. Fatigue - corrosion of endoprosthesis titanium alloys.

    Science.gov (United States)

    Cornet, A; Muster, D; Jaeger, J H

    1979-01-01

    Commercial total hip prostheses often show certain metallurgical faults (porosities, coarse grains, growth dendrites, carbide networks). In order to investigate more accurately the role played by these different parameters in prostheses failure we performed a large number of systematic corrosion, fatigue and fatigue - corrosion tests on these materials and on commercial total hip prostheses. Ultimate strengthes seem to be reached for cast cobalt alloys, whereas titanium alloys, such as Ta 6 V, present very high fatigue limit under corrosion. Thus, rotative bending fatigue - corrosion tests in biological environment provide values about 50 DaN/mm2. This value, is nevertheless appreciably higher than those obtained with stellites and stainless steel. Titanium alloys, because of their mechanical performances, their weak Young's modulus (11000 DaN/mm2) and their relative lightness (4.5. g/cm3), which are associated with a good biocompatibility, seem very promising for permanent implants realisation.

  9. Cast Aluminum Alloy for High Temperature Applications

    Science.gov (United States)

    Lee, Jonathan A.

    2003-01-01

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

  10. Aluminum-lithium alloy development for thixoforming

    Energy Technology Data Exchange (ETDEWEB)

    Sauermann, R.; Friedrich, B. [IME Process Metallurgy and Metal Recycling, RWTH Aachen Univ. (Germany); Puettgen, W.; Bleck, W. [IEHK Inst. for Ferrous Metallurgy, RWTH Aachen Univ. (Germany); Balitchev, E.; Hallstedt, B.; Schneider, J.M. [MCh Materials Chemistry, RWTH Aachen Univ. (Germany); Bramann, H.; Buehrig-Polaczek, A. [GI Foundry Inst., RWTH Aachen Univ. (Germany); Uggowitzer, P.J. [ETH Zuerich, Metal Physics and Technology (Germany)

    2004-12-01

    This paper presents a scientific contribution to the development of lightweight/high-performance Al-Li alloys suitable for semi-solid processing. Thermodynamic calculations identified the most promising compositions with focus on the solidus-liquidus interval, fraction of solid-versus-temperature and phase reactions. The synthesis of Al-Li precursor billets was performed by overpressure induction melting in controlled atmosphere. DTA and microstructure investigations on Al-Li specimens were carried out as well as thixocasting trials of demonstrator components. New rheocasting of Al-Li alloys was investigated to identify the potential of this alternative precursor material route. It is shown that specifically developed Al-Li alloys offer great potential for semi-solid manufacturing. (orig.)

  11. High-strength iron aluminide alloys

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-06-01

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

  12. Microstructure and Service Properties of Copper Alloys

    Directory of Open Access Journals (Sweden)

    Polok-Rubiniec M.

    2016-09-01

    Full Text Available This elaboration shows the effect of combined heat treatment and cold working on the structure and utility properties of alloyed copper. As the test material, alloyed copper CuTi4 was employed. The samples were subjected to treatment according to the following schema: 1st variant – supersaturation and ageing, 2nd variant – supersaturation, cold rolling and ageing. The paper presents the results of microstructure, hardness, and abrasion resistance. The analysis of the wipe profile geometry was realized using a Zeiss LSM 5 Exciter confocal microscope. Cold working of the supersaturated solid solution affects significantly its hardness but the cold plastic deformation causes deterioration of the wear resistance of the finally aged CuTi4 alloy.

  13. The metallurgy of high temperature alloys

    Science.gov (United States)

    Tien, J. K.; Purushothaman, S.

    1976-01-01

    Nickel-base, cobalt-base, and high nickel and chromium iron-base alloys are dissected, and their microstructural and chemical components are assessed with respect to the various functions expected of high temperature structural materials. These functions include the maintenance of mechanical integrity over the strain-rate spectrum from creep resistance through fatigue crack growth resistance, and such alloy stability expectations as microstructural coarsening resistance, phase instability resistance and oxidation and corrosion resistance. Special attention will be given to the perennial conflict and trade-off between strength, ductility and corrosion and oxidation resistance. The newest developments in the constitution of high temperature alloys will also be discussed, including aspects relating to materials conservation.

  14. General aspects of surface alloy formation

    Energy Technology Data Exchange (ETDEWEB)

    Bergbreiter, Andreas; Engstfeld, Albert K.; Roetter, Ralf T.; Hoster, Harry E.; Behm, R. Juergen [Institute of Surface Chemistry and Catalysis, Ulm University, D-89069 Ulm (Germany); Berko, Andras

    2010-07-01

    Surface confined alloys are excellent model systems for studies of structure-property relationships of bimetallic surfaces. They are formed by deposition of a guest metal B onto a substrate A, followed by annealing to a temperature, where place exchange between adatoms and atoms from the underlying surface layer becomes possible and diffusion into the bulk is sufficiently slow. We exemplarily confirmed by scanning tunneling microscopy and Auger electron spectroscopy for PtRu/Ru(0001), PdRu/Ru(0001), AuPt/Pt(111), AgPt/Pt(111), and AgPd/Pd(111), surface alloys are obtained for systems where metal B has a negative surface segregation energy within metal A. By exchanging A and B, however, AB surface alloys are most likely overgrown by metal B, which we demonstrate for RuPt/Pt(111) in comparison to PtRu/Ru(0001).

  15. Irradiation creep of vanadium-base alloys

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, H.; Billone, M.C.; Strain, R.V.; Smith, D.L. [Argonne National Lab., IL (United States); Matsui, H. [Tohoku Univ. (Japan)

    1998-03-01

    A study of irradiation creep in vanadium-base alloys is underway with experiments in the Advanced Test Reactor (ATR) and the High Flux Isotope Reactor (HFIR) in the United States. Test specimens are thin-wall sealed tubes with internal pressure loading. The results from the initial ATR irradiation at low temperature (200--300 C) to a neutron damage level of 4.7 dpa show creep rates ranging from {approx}0 to 1.2 {times} 10{sup {minus}5}/dpa/MPa for a 500-kg heat of V-4Cr-4Ti alloy. These rates were generally lower than reported from a previous experiment in BR-10. Because both the attained neutron damage levels and the creep strains were low in the present study, however, these creep rates should be regarded as only preliminary. Substantially more testing is required before a data base on irradiation creep of vanadium alloys can be developed and used with confidence.

  16. Joining Techniques for Ferritic ODS Alloys

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-06-01

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

  17. Microstructural and magnetic behavior of an equiatomic NiCoAlFe alloy prepared by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Gómez-Esparza, C.D.; Baldenebro-López, F.J.; Santillán-Rodríguez, C.R.; Estrada-Guel, I.; Matutes-Aquino, J.A.; Herrera-Ramírez, J.M., E-mail: martin.herrera@cimav.edu.mx; Martínez-Sánchez, R.

    2014-12-05

    Highlights: • Equiatomic NiCoAlFe powder alloys were synthesized by mechanical alloying. • The nanocrystalline alloys were characterized after milled and annealed conditions. • In alloyed and annealed powders, only BCC and FCC structure phases were observed. • Magnetic properties are strongly affected by the phases formed after annealing. - Abstract: Equiatomic NiCoAlFe powder alloys were synthesized by mechanical alloying. The microstructural evolution of the mechanically alloyed powders at different times was followed with X-ray diffraction and scanning electron microscopy. The as-mechanically alloyed powders were subjected to a rapid annealing treatment at 1273 K and 1473 K during 3 min in vacuum. X-ray diffraction studies show the structure of both, the as-mechanically alloyed and annealed powders, consisted in a mixture of nanocrystalline simple phases (FCC + BCC). Crystallite size, after annealing, still remained in nanoscale. Coercivity increased due to the decrease in crystallite size and because of the defects caused by mechanical alloying in the as-mechanically alloyed samples; then coercivity decreased due to the phenomenon of random magnetic anisotropy and tended to stabilize with longer alloying times. A similar behavior was observed in annealed samples at 1273 K. However, random magnetic anisotropy was not observed after annealing at 1473 K because crystals with larger sizes were produced, and a steady increase in coercivity was observed.

  18. Fast LIBS Identification of Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    Tawfik W.

    2007-04-01

    Full Text Available Laser-induced breakdown spectroscopy (LIBS has been applied to analysis aluminum alloy targets. The plasma is generated by focusing a 300 mJ pulsed Nd: YAG laser on the target in air at atmospheric pressure. Such plasma emission spectrum was collected using a one-meter length wide band fused-silica optical fiber connected to a portable Echelle spectrometer with intensified CCD camera. Spectroscopic analysis of plasma evolution of laser produced plasmas has been characterized in terms of their spectra, electron density and electron temperature assuming the LTE and optically thin plasma conditions. The LIBS spectrum was optimized for high S/N ratio especially for trace elements. The electron temperature and density were determined using the emission intensity and stark broadening, respectively, of selected aluminum spectral lines. The values of these parameters were found to change with the aluminum alloy matrix, i.e. they could be used as a fingerprint character to distinguish between different aluminum alloy matrices using only one major element (aluminum without needing to analysis the rest of elements in the matrix. Moreover, It was found that the values of T e and N e decrease with increasing the trace elements concentrations in the aluminum alloy samples. The obtained results indicate that it is possible to improve the exploitation of LIBS in the remote on-line industrial monitoring application, by following up only the values of T e and N e for aluminum in aluminum alloys as a marker for the correct alloying using an optical fiber probe.

  19. Irradiation creep of dispersion strengthened copper alloy

    Energy Technology Data Exchange (ETDEWEB)

    Pokrovsky, A.S.; Barabash, V.R.; Fabritsiev, S.A. [and others

    1997-04-01

    Dispersion strengthened copper alloys are under consideration as reference materials for the ITER plasma facing components. Irradiation creep is one of the parameters which must be assessed because of its importance for the lifetime prediction of these components. In this study the irradiation creep of a dispersion strengthened copper (DS) alloy has been investigated. The alloy selected for evaluation, MAGT-0.2, which contains 0.2 wt.% Al{sub 2}O{sub 3}, is very similar to the GlidCop{trademark} alloy referred to as Al20. Irradiation creep was investigated using HE pressurized tubes. The tubes were machined from rod stock, then stainless steel caps were brazed onto the end of each tube. The creep specimens were pressurized by use of ultra-pure He and the stainless steel caps subsequently sealed by laser welding. These specimens were irradiated in reactor water in the core position of the SM-2 reactors to a fluence level of 4.5-7.1 x 10{sup 21} n/cm{sup 2} (E>0.1 MeV), which corresponds to {approx}3-5 dpa. The irradiation temperature ranged from 60-90{degrees}C, which yielded calculated hoop stresses from 39-117 MPa. A mechanical micrometer system was used to measure the outer diameter of the specimens before and after irradiation, with an accuracy of {+-}0.001 mm. The irradiation creep was calculated based on the change in the diameter. Comparison of pre- and post-irradiation diameter measurements indicates that irradiation induced creep is indeed observed in this alloy at low temperatures, with a creep rate as high as {approx}2 x 10{sup {minus}9}s{sup {minus}1}. These results are compared with available data for irradiation creep for stainless steels, pure copper, and for thermal creep of copper alloys.

  20. Characterization for Fusion Candidate Vanadium Alloys

    Institute of Scientific and Technical Information of China (English)

    T. Muroga; T. Nagasaka; J. M. Chen; Z. Y. Xu; Q. Y. Huang; y. C. Wu

    2004-01-01

    This paper summarizes recent achievements in the characterization of candidate vanadium alloys obtained for fusion in the framework of the Japan-China Core University Program.National Institute for Fusion Science (NIFS) has a program of fabricating high-purity V-4Cr4Ti alloys. The resulting products (NIFS-HEAT-1,2), were characterized by various research groups in the world including Chinese partners. South Western Institute of Physics (SWIP) fabricated a new V-4Cr-4Ti alloy (SWIP-Heat), and carried out a comparative evaluation of hydrogen embrittlement of NIFS-HEATs and SWIP-Heat. The tensile test of hydrogen-doped alloys showed that the NIFS-HEAT maintained the ductility to relatively high hydrogen levels.The comparison of the data with those of previous studies suggested that the reduced oxygen level in the NIFS-HEATs should be responsible for the increased resistance to hydrogen embrittlement.Based on the chemical analysis data of NIFS-HEATs and SWIP-Heats, neutron-induced activation was analyzed in Institute of Plasma Physics (IPP-CAS) as a function of cooling time after the use in the fusion first wall. The results showed that the low level of Co dominates the activity up to 50 years followed by a domination of Nb or Nb and Al in the respective alloys. It was suggested that reduction of Co and Nb, both of which are thought to have been introduced via cross-contamination into the alloys from the molds used should be crucial for reducing further the activation.