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Sample records for titanium aluminide articles

  1. Welding and Joining of Titanium Aluminides

    Science.gov (United States)

    Cao, Jian; Qi, Junlei; Song, Xiaoguo; Feng, Jicai

    2014-01-01

    Welding and joining of titanium aluminides is the key to making them more attractive in industrial fields. The purpose of this review is to provide a comprehensive overview of recent progress in welding and joining of titanium aluminides, as well as to introduce current research and application. The possible methods available for titanium aluminides involve brazing, diffusion bonding, fusion welding, friction welding and reactive joining. Of the numerous methods, solid-state diffusion bonding and vacuum brazing have been most heavily investigated for producing reliable joints. The current state of understanding and development of every welding and joining method for titanium aluminides is addressed respectively. The focus is on the fundamental understanding of microstructure characteristics and processing–microstructure–property relationships in the welding and joining of titanium aluminides to themselves and to other materials. PMID:28788113

  2. Welding and Joining of Titanium Aluminides

    Directory of Open Access Journals (Sweden)

    Jian Cao

    2014-06-01

    Full Text Available Welding and joining of titanium aluminides is the key to making them more attractive in industrial fields. The purpose of this review is to provide a comprehensive overview of recent progress in welding and joining of titanium aluminides, as well as to introduce current research and application. The possible methods available for titanium aluminides involve brazing, diffusion bonding, fusion welding, friction welding and reactive joining. Of the numerous methods, solid-state diffusion bonding and vacuum brazing have been most heavily investigated for producing reliable joints. The current state of understanding and development of every welding and joining method for titanium aluminides is addressed respectively. The focus is on the fundamental understanding of microstructure characteristics and processing–microstructure–property relationships in the welding and joining of titanium aluminides to themselves and to other materials.

  3. Isothermal deformation of gamma titanium aluminide

    International Nuclear Information System (INIS)

    Srinivasan, R.; Singh, J.P.; Tuval, E.; Weiss, I.

    1996-01-01

    Gamma titanium aluminide has received considerable attention in recent years from the automotive industry as a potential material for making rotating and reciprocating components to produce a quieter and more efficient engine. The objectives of this study were to identify processing routes for the manufacture of automobile valves from gamma titanium aluminide. The issues considered were microstructure and composition of the material, and processing parameters such as deformation rates, temperatures, and total deformation. This paper examines isothermal deformation of gamma titanium aluminide in order to develop a processing window for this type of material

  4. Titanium Aluminide Casting Technology Development

    Science.gov (United States)

    Bünck, Matthias; Stoyanov, Todor; Schievenbusch, Jan; Michels, Heiner; Gußfeld, Alexander

    2017-12-01

    Titanium aluminide alloys have been successfully introduced into civil aircraft engine technology in recent years, and a significant order volume increase is expected in the near future. Due to its beneficial buy-to-fly ratio, investment casting bears the highest potential for cost reduction of all competing production technologies for TiAl-LPTB. However, highest mechanical properties can be achieved by TiAl forging. In view of this, Access e.V. has developed technologies for the production of TiAl investment cast parts and TiAl die cast billets for forging purposes. While these parts meet the highest requirements, establishing series production and further optimizing resource and economic efficiency are present challenges. In order to meet these goals, Access has recently been certified according to aircraft standards, aiming at qualifying parts for production on technology readiness level 6. The present work gives an overview of the phases of development and certification.

  5. Method for producing titanium aluminide weld rod

    Science.gov (United States)

    Hansen, Jeffrey S.; Turner, Paul C.; Argetsinger, Edward R.

    1995-01-01

    A process for producing titanium aluminide weld rod comprising: attaching one end of a metal tube to a vacuum line; placing a means between said vacuum line and a junction of the metal tube to prevent powder from entering the vacuum line; inducing a vacuum within the tube; placing a mixture of titanium and aluminum powder in the tube and employing means to impact the powder in the tube to a filled tube; heating the tube in the vacuum at a temperature sufficient to initiate a high-temperature synthesis (SHS) reaction between the titanium and aluminum; and lowering the temperature to ambient temperature to obtain a intermetallic titanium aluminide alloy weld rod.

  6. Two phase titanium aluminide alloy

    Energy Technology Data Exchange (ETDEWEB)

    Deevi, Seetharama C. (Midlothian, VA); Liu, C. T. (Oak Ridge, TN)

    2001-01-01

    A two-phase titanic aluminide alloy having a lamellar microstructure with little intercolony structures. The alloy can include fine particles such as boride particles at colony boundaries and/or grain boundary equiaxed structures. The alloy can include alloying additions such as .ltoreq.10 at % W, Nb and/or Mo. The alloy can be free of Cr, V, Mn, Cu and/or Ni and can include, in atomic %, 45 to 55% Ti, 40 to 50% Al, 1 to 5% Nb, 0.3 to 2% W, up to 1% Mo and 0.1 to 0.3% B. In weight %, the alloy can include 57 to 60% Ti, 30 to 32% Al, 4 to 9% Nb, up to 2% Mo, 2 to 8% W and 0.02 to 0.08% B.

  7. Titanium aluminide intermetallic alloys with improved wear resistance

    Science.gov (United States)

    Qu, Jun; Lin, Hua-Tay; Blau, Peter J.; Sikka, Vinod K.

    2014-07-08

    The invention is directed to a method for producing a titanium aluminide intermetallic alloy composition having an improved wear resistance, the method comprising heating a titanium aluminide intermetallic alloy material in an oxygen-containing environment at a temperature and for a time sufficient to produce a top oxide layer and underlying oxygen-diffused layer, followed by removal of the top oxide layer such that the oxygen-diffused layer is exposed. The invention is also directed to the resulting oxygen-diffused titanium aluminide intermetallic alloy, as well as mechanical components or devices containing the improved alloy composition.

  8. As-cast titanium aluminides microstructure modification

    Directory of Open Access Journals (Sweden)

    A. Duarte

    1999-07-01

    Full Text Available Two cast g titanium aluminides, Ti47Al and Ti50Al (at. %, were obtained by arc melting under an argon atmosphere. The as-cast microstructure modification by annealing under protective argon atmosphere and hot isostatic pressing (HIP was analysed by optical and scanning electron microscopy with microanalysis facilities. As-cast structures presented strong microsegregations, being composed of primary a dendrites (with low Al content, which transformed into lamellar a2 + g during solid state cooling, and interdendritic g phase (with high Al content. Annealing in the a + g field was responsible for a partial reduction of microsegregation, a decreasing of the volume fraction of a2 + g lamellar dendrites, an increasing of g volume fraction and the occurrence of a small fraction of a2 particles and plates in some of the g grains. Annealing in the a field at 1400 °C for one hour was insufficient to eliminate the as-cast microstructure in the Ti50Al alloy and produced large equiaxed lamellar colonies of a2+g in the Ti47Al alloy. HIP in the a + g field (to avoid excessive grain growth was responsible for microstructure modifications similar to the ones obtained by heat treating under similar soaking conditions.

  9. Use of gamma titanium aluminide for automotive engine valves

    OpenAIRE

    Chandley, D.

    2013-01-01

    Titanium aluminade is considered an interesting material for the automotive industry when applied to light hot components because of their peculiar properties.In particular the tensile strenght which is higher in the 700-800 °C range there at room temperature.Compared with special steel used at high temperature (21-2N) the titanium aluminide is 50% lower in density and the termal expansion is also interestihgly lower.A suitable casting technology has been developed with the goal of having a l...

  10. Microstructures and superplasticity in near-gamma titanium aluminide alloys

    International Nuclear Information System (INIS)

    Bampton, C.C.; Martin, P.L.

    1993-01-01

    Microstructure control by thermomechanical processing in near-gamma titanium aluminide alloys has recently progressed to a point where the authors are able to reliably produce a wide range of microstructures in a single alloy. The authors are now studying the basic superplastic deformation microstructures. Correlations are made between microstructural details and flow stress, strain hardening, strain-rate hardening, necking, cavitation and failure. Special emphasis is given to the cavitation behavior since this phenomenon may constitute a major limitation to the useful application of superplastic forming for gamma TiAl structures

  11. Advances in the Systems and Processes for the Production of Gamma Titanium Aluminide Bars and Powder

    Science.gov (United States)

    Haun, Robert E.

    2017-12-01

    A historical look at the melt processing of gamma titanium aluminides is presented first, followed by recent advances in melting equipment design by Retech to produce 50-mm and 100-mm-diameter ingots up to 1000 mm long. Equipment design for the economical production of gamma titanium aluminide powder is then discussed. The focus in industry has shifted away from basic research to cost-effective production of these titanium alloys for aerospace and automotive engine applications.

  12. Structural formation of aluminide phases on titanium alloy during annealing

    International Nuclear Information System (INIS)

    Mamaeva, A.A.; Romankov, S.E.; Sagdoldina, Zh.

    2006-01-01

    Full text: The aluminum layer on the surface of titanium alloy has been formed by thermal deposition. The structural formation of aluminide phases on the surface has been studied. The sequence of structural transformations at the Ti/Al interface is limited by the reaction temperature and time. The sequence of aluminide phase formation is occurred in compliance with Ti-Al equilibrium phase diagram. At the initial stages at the Ti/Al interface the Al3Ti alloy starts forming as a result of interdiffusion, and gradually the whole aluminum films is spent on the formation of this layer. The Al3Ti layer decomposes with the increase of temperature (>600C). At 800C the two-phase (Ti3Al+TiAl) layer is formed on the titanium surface. The TiAl compound is unstable and later on with the increase of the exposure time at 800C gradually transforms into the Ti3Al. The chain of these successive transformations leads to the formation of the continuous homogeneous layer consisting of the Ti3Al compound on the surface. At temperatures exceeding the allotropic transformation temperature (>900C) the Ti3Al compound starts decomposing. All structural changes taking place at the Ti/Al interface are accompanied by considerable changes in micro hardness. The structure of initial substrate influences on kinetics of phase transformation and microstructure development. (author)

  13. Gamma titanium aluminide production using the Induction Skull Melting (ISM) process

    International Nuclear Information System (INIS)

    Reed, S.

    1995-01-01

    Since 1985, more than 2,000 titanium aluminide heats have been produced using the Induction Skull Melting (ISM) process. The history of ISM/Gamma production will be discussed in this paper. Gamma titanium aluminide processing with Induction Skull Melting offers many advantages over other types of reactive alloy melting methods. These advantages will be discussed as well as drawbacks. Also, potential markets and applications for ISM/Gamma will be presented

  14. Texture of uniaxial compressed two-phase titanium-aluminides

    International Nuclear Information System (INIS)

    Bermig, G.; Tobisch, J.; Brokmeier, H.G.; Wurzwallner, K.

    1993-01-01

    Texture is, among others, an essential parameter to document the different states of a polycrystalline material from production to application. Therefore, texture studies were carried out in γ-base titanium aluminide series, Ti-48at%Al and Ti-48at%Al-2at%Cr, in order to describe their microstructural changes during uniaxial compression. The fabrication of the material started by casting an ingot of the desired composition. After hot isostatic pressing (HIP) the specimens were deformed up to 77% with a compression rate of ∼ 10mm/s, X-ray diffraction and microscopical investigations confirm the expected two-phase material composition of tetragonal γ-Tial and hexagonal α 2 -Ti 3 Al respectively. The texture measurements were carried out by X-ray as well as by neutron diffraction. A comparison of both techniques is necessary in order to document that only a combination of X-ray and neutron diffraction allows to obtain the whole texture information of all samples. Finally, the determined textures are discussed in correlation with deformation. (orig.)

  15. A process for the fabrication of ceramic fibre reinforced titanium aluminide

    OpenAIRE

    Horsfall, Ian; Cundy, S. J.

    1992-01-01

    This paper describes initial work on a novel process for the production of titanium aluminide matrix composites reinforced with short alumina fibers. The processing route involves an adaption of existing metal matrix composite (MMC) fabrication technology used to produce hybrid particulate/short fiber composites. A preform is produced which contains alumina fibers and titanium metal powder with a fiber content of around 10% by volume and approximately 50% porosity. This preform is then infilt...

  16. Measurement of the effective activation volume in 45XD titanium aluminides by repeated transient tests

    Czech Academy of Sciences Publication Activity Database

    Diologent, F.; Kruml, Tomáš

    2008-01-01

    Roč. 487, č. 1-2 (2008), s. 377-382 ISSN 0921-5093 R&D Projects: GA ČR GA106/07/0762; GA ČR(CZ) GA106/05/0495 Institutional research plan: CEZ:AV0Z20410507 Keywords : Titanium aluminides * Mechanical properties * Plastic deformation mechanisms * Activation volume * Stress relaxation Subject RIV: JJ - Other Materials Impact factor: 1.806, year: 2008

  17. Additive manufacturing of a high niobium-containing titanium aluminide alloy by selective electron beam melting

    International Nuclear Information System (INIS)

    Tang, H.P.; Yang, G.Y.; Jia, W.P.; He, W.W.; Lu, S.L.; Qian, M.

    2015-01-01

    Additive manufacturing (AM) offers a radical net-shape manufacturing approach for titanium aluminide alloys but significant challenges still remain. A study has been made of the AM of a high niobium-containing titanium aluminide alloy (Ti–45Al–7Nb–0.3W, in at% throughout the paper) using selective electron beam melting (SEBM). The formation of various types of microstructural defects, including banded structures caused by the vaporization of aluminum, was investigated with respect to different processing parameters. To avoid both micro- and macro-cracks, the use of higher preheating temperatures and an intermediate reheating process (to reheat each solidified layer during SEBM) was assessed in detail. These measures enabled effective release of the thermal stress that developed during SEBM and therefore the avoidance of cracks. In addition, the processing conditions for the production of a fine full lamellar microstructure were identified. As a result, the Ti–45Al–7Nb–0.3W alloy fabricated showed outstanding properties (compression strength: 2750 MPa; strain-to-fracture: 37%). SEBM can be used to fabricate high performance titanium aluminide alloys with appropriate processing parameters and pathways

  18. Effect of microstructures on the hydrogen attack to gamma titanium aluminide at low temperature

    International Nuclear Information System (INIS)

    Hamzah, E.; Suardi, K.; Ourdjini, A.

    2005-01-01

    Intermetallic alloys based on gamma titanium aluminide are now regarded as promising candidates for high temperature applications such as for aerospace, marine and automotive engine components, due to their high specific strength and modulus. Their oxidation resistance is good, especially at intermediate and high temperature; oxidation resistance can be obtained up to 800 deg. C. One critical area of application is in combustion engines in aerospace vehicles such as hypersonic airplanes and high-speed civil transport airplanes. This entails the use of hydrogen as a fuel component and it has been widely reported by researchers that these materials exhibit corrosion in the form of environment embrittlement in the presence of hydrogen. A fair amount of research has been carried out to investigate the influence of hydrogen in γ-titanium aluminide. Some researchers reported that α 2 and lamellar phases had major influence in the susceptible of hydrogen to alloys, while hydrogen is too low to penetrate the γ-phases. This research focused on the effect of different microstructures of γ-titanium aluminide to the diffusion coefficient of hydrogen (D) and the corrosion product after hydrogen attack. Modification of γ-titanium aluminide can be achieved by heat treatment of as-cast binary samples Ti-45% Al and Ti-48% Al. All samples were then subjected to corrosion attack under cathodically charged with galvanostatic mode for 6 h. The potential variation with time was monitored from these data the values of the diffusion coefficient of hydrogen (D) to γ-titanium aluminide was obtained. D was calculated based on Fick's second Law. These results were compared with that obtained from micro-Vickers hardness profiling, which was measured at cross-section area per depth from the top corroded surface. The hardness values were calculated using the error function equation. An image analyzer; X-ray diffraction (XRD); scanning electron microscope (SEM) and secondary ion mass

  19. Effect of microstructures on the hydrogen attack to gamma titanium aluminide at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Hamzah, E. [Faculty of Mechanical Engineering, Universiti Technologi Malaysia 81310, Johor Bahru (Malaysia)]. E-mail: esah@fkm.utm.my; Suardi, K. [Faculty of Mechanical Engineering, Universiti Technologi Malaysia 81310, Johor Bahru (Malaysia); Ourdjini, A. [Faculty of Mechanical Engineering, Universiti Technologi Malaysia 81310, Johor Bahru (Malaysia)

    2005-04-25

    Intermetallic alloys based on gamma titanium aluminide are now regarded as promising candidates for high temperature applications such as for aerospace, marine and automotive engine components, due to their high specific strength and modulus. Their oxidation resistance is good, especially at intermediate and high temperature; oxidation resistance can be obtained up to 800 deg. C. One critical area of application is in combustion engines in aerospace vehicles such as hypersonic airplanes and high-speed civil transport airplanes. This entails the use of hydrogen as a fuel component and it has been widely reported by researchers that these materials exhibit corrosion in the form of environment embrittlement in the presence of hydrogen. A fair amount of research has been carried out to investigate the influence of hydrogen in {gamma}-titanium aluminide. Some researchers reported that {alpha}{sub 2} and lamellar phases had major influence in the susceptible of hydrogen to alloys, while hydrogen is too low to penetrate the {gamma}-phases. This research focused on the effect of different microstructures of {gamma}-titanium aluminide to the diffusion coefficient of hydrogen (D) and the corrosion product after hydrogen attack. Modification of {gamma}-titanium aluminide can be achieved by heat treatment of as-cast binary samples Ti-45% Al and Ti-48% Al. All samples were then subjected to corrosion attack under cathodically charged with galvanostatic mode for 6 h. The potential variation with time was monitored from these data the values of the diffusion coefficient of hydrogen (D) to {gamma}-titanium aluminide was obtained. D was calculated based on Fick's second Law. These results were compared with that obtained from micro-Vickers hardness profiling, which was measured at cross-section area per depth from the top corroded surface. The hardness values were calculated using the error function equation. An image analyzer; X-ray diffraction (XRD); scanning electron

  20. Thermal and Irradiation Creep Behavior of a Titanium Aluminide in Advanced Nuclear Plant Environments

    Science.gov (United States)

    Magnusson, Per; Chen, Jiachao; Hoffelner, Wolfgang

    2009-12-01

    Titanium aluminides are well-accepted elevated temperature materials. In conventional applications, their poor oxidation resistance limits the maximum operating temperature. Advanced reactors operate in nonoxidizing environments. This could enlarge the applicability of these materials to higher temperatures. The behavior of a cast gamma-alpha-2 TiAl was investigated under thermal and irradiation conditions. Irradiation creep was studied in beam using helium implantation. Dog-bone samples of dimensions 10 × 2 × 0.2 mm3 were investigated in a temperature range of 300 °C to 500 °C under irradiation, and significant creep strains were detected. At temperatures above 500 °C, thermal creep becomes the predominant mechanism. Thermal creep was investigated at temperatures up to 900 °C without irradiation with samples of the same geometry. The results are compared with other materials considered for advanced fission applications. These are a ferritic oxide-dispersion-strengthened material (PM2000) and the nickel-base superalloy IN617. A better thermal creep behavior than IN617 was found in the entire temperature range. Up to 900 °C, the expected 104 hour stress rupture properties exceeded even those of the ODS alloy. The irradiation creep performance of the titanium aluminide was comparable with the ODS steels. For IN617, no irradiation creep experiments were performed due to the expected low irradiation resistance (swelling, helium embrittlement) of nickel-base alloys.

  1. Microstructure control and engineering characterization of super-α2 titanium aluminide alloys

    International Nuclear Information System (INIS)

    Wang, Wego; Wells, G.H.

    1993-01-01

    Various microstructures evolved during four different heat treatments and the engineering characteristics of respective microstructure of a super-α 2 titanium aluminide alloy were studied. This alloy was consolidated by the rapid omnidirectional compaction (ROC) process of prealloyed Ti-25Al-10Nb-3V-1Mo. The process-microstructure-property relationships of this alloy and five other similar super-α 2 alloys were investigated, reviewed and compared. The constituent phase morphology has profound effects on the mechanical properties. Three rules regarding these effects are discussed. However, the crack nucleation and propagation during the fracture deformation are constituent phase morphology independent. High-temperature fracture mechanisms are discussed. The ROC'ed alloy has better mechanical properties than that of a hot-isostatically pressed alloy

  2. Effects of stress concentrations on the fatigue life of a gamma based titanium aluminide

    International Nuclear Information System (INIS)

    Trail, S.J.; Bowen, P.

    1995-01-01

    S-N curves for a gamma based titanium aluminide alloy of composition Ti-47.2Al-2.1Mn-1.9Nb(at.%)+2TiB 2 (wt.%) have been used to define fatigue life. Effects of residual stress, stressed volume, loading ratio, loading mode, elevated temperature and surface roughness have been considered. Residual tensile stresses and micro-cracking are introduced by Electro Discharge Machining and the fatigue life is reduced slightly compared with polished samples. Notched fatigue tests show a significant notch strengthening effect which increases with increasing stress concentration factor. The fracture surfaces of specimens tested at room temperature reveal fully brittle failure mechanisms and no evidence of stable crack growth is observed. The fatigue life appears, therefore, to be determined predominantly by the number of cycles to crack initiation. At the elevated temperature of 830 C, evidence for some stable fatigue crack growth has been found. Probable sites for crack initiation are addressed

  3. Development of a dynamic recrystallization model for a β-solidifying titanium aluminide alloy using Kocks-Mecking plots

    Science.gov (United States)

    Bambach, Markus; Sizova, Irina; Bolz, Sebastian; Weiß, Sabine

    2016-10-01

    Intermetallic titanium aluminide alloys are of growing interest for aerospace and automotive industries due to their remarkable mechanical properties at elevated temperature. The present study focusses on the investigation of the high-temperature deformation behavior of an intermetallic alloy with the nominal composition Ti-44.5Al-6.25Nb-0.8Mo-0.1B. Isothermal compression tests were conducted on a Gleeble 3500 simulator. The flow curves were transformed into Kocks-Mecking plots, where remarkable features such as the absence of stage-III hardening and an inflection point marking the onset of dynamic recrystallization were observed. Based on these observations, a phenomenological flow stress model was devised which incorporates the observations revealed through the Kocks-Mecking plots and reproduces the course of flow stress up to the peak stress and towards the steady-state well. The model may hence be used in finite element simulations of isothermal forging of titanium aluminides.

  4. Microstructure evaluation and mechanical behavior of high-niobium containing titanium aluminides

    Science.gov (United States)

    Bean, Glenn Estep, Jr.

    Ti-Al-Nb-based alloys with gamma(TiAl)+sigma(Nb2Al) microstructure have shown promise for potential high temperature applications due to their high specific strength. Recent research has been aimed towards increasing strength and operating temperatures through microstructural refinement and control. Alloys with 10 - 30% sigma-phase have been investigated, exploring relationships between chemistry, microstructure development, and flow behavior. Alloys with composition Ti-45Al-xNb-5Cr-1Mo (where x = 15, 20, 25 at%) have been produced, characterized, and tested at high temperature under compression. Processing, microstructure and mechanical property relationships are thoroughly investigated to reveal a significant connection between phase stability, morphology and their resultant effects on mechanical properties. Phase transformation temperatures and stability ranges were predicted using the ThermoCalc software program and a titanium aluminide database, investigated through thermal analysis, and alloys were heat treated to develop an ultrafine gamma+sigma microstructure. It has been demonstrated that microstructural development in these alloys is sensitive to composition and processing parameters, and heating and cooling rates are vital to the modification of gamma+sigma microstructure in these alloys. Towards the goal of designing a high-Nb titanium aluminide with ultrafine, disconnected gamma+sigma morphology, it has been established that microstructural control can be accomplished in alloys containing 15-25at% Nb through targeted chemistry and processing controls. The strength and flow softening characteristics show strain rate sensitivity that is also affected by temperature. From the standpoint of microstructure development and mechanical behavior at elevated temperature, the most favorable results are obtained with the 20 at% Nb alloy, which produces a combination of high strength and fine disconnected gamma+sigma microstructure. Microstructural analysis reveals

  5. Microcracking and macroscopic failure in intermetallic titanium aluminides; Mikrorissbildung und makroskopisches Versagen in intermetallischen Titanaluminiden

    Energy Technology Data Exchange (ETDEWEB)

    Wiesand-Valk, B. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Werkstofforschung

    2000-07-01

    This paper deals with the correlations between microstructural disorder, that means statistical distribution of phases and local material properties, and macroscopic failure of disordered multiphase materials. On a microscopic level the microstructural disorder leads to randomly distributed local damage before failure (in brittle materials to microcracks) and eventually to localisation of damage. On a macroscopic level the value and scatter of fracture strength and its dependence on specimen size are essentially determined by the microstructural disorder. The failure behaviour is treated by using the discrete chain-of-bundles-model, which treats the details of the microstructure not explicitly but as locally distributed fluctuations of characteristical material parameters. The model has been verified by comparing with experimental results for four intermetallic titanium aluminides and its validity has been demonstrated. (orig.) [German] Die Arbeit behandelt die Zusammenhaenge zwischen der Stochastizitaet des Gefueges, das heisst, einer statistischen Verteilung von Phasen und lokalen Materialeigenschaften und dem makroskopischen Versagen von ungeordneten mehrphasigen Werkstoffen. Auf mikroskopischer Ebene fuehrt die Stochastizitaet des Gefueges vor dem Versagen zu lokalen Schaedigungen (in sproeden Werkstoffen zu Mikrorissen) und schliesslich (abhaengig vom Grad der Unordnung) zur Lokalisierung des Bruchgeschehens. Makroskopisch werden die Groesse und Streuung von Bruchfestigkeitswerten und ihre Probengroessenabhaengigkeit durch die mikrostrukturelle Unordnung wesentlich bestimmt. Dieses Versagensverhalten wird in dem diskreten Chain-of-Bundles-Modell beschrieben, das die Details der Mikrostruktur nicht explizit sondern als lokale statistische Schwankungen von charakteristischen Werkstoffparametern erfasst. Am Beispiel von vier ausgewaehlten Titan-Aluminiden wird das Modell validiert und verifiziert. (orig.)

  6. Sintering Behavior and Microstructure Formation of Titanium Aluminide Alloys Processed by Metal Injection Molding

    Science.gov (United States)

    Soyama, Juliano; Oehring, Michael; Ebel, Thomas; Kainer, Karl Ulrich; Pyczak, Florian

    2017-04-01

    The sintering behavior of metal injection molded titanium aluminide alloys, their microstructure formation and resulting mechanical properties were investigated. As reference material, the alloy Ti-45Al-5Nb-0.2B-0.2C at.% (TNB-V5) was selected. Additionally, two other variations with Mo and Mo + Si additions were prepared: Ti-45Al-3Nb-1Mo-0.2B-0.2C at.% and Ti-45Al-3Nb-1Mo-1Si-0.2B-0.2C at.%. The results indicate that the optimum sintering temperature was slightly above the solidus line. With proper sintering parameters, very low porosities (<0.5%) and fine microstructures with a colony size <85 µm could be achieved. Considering the sintering temperatures applied, the phase transformations upon cooling could be described as L + β → β → α + β → α → α + γ → α2 + γ, which was in agreement with the microstructures observed. The effects of Mo and Si were opposite regarding the sintering behavior. Mo addition led to an increase in the optimum sintering temperature, whereas Si caused a significant decrease.

  7. Optimization of the manufacturing process of a titanium aluminide metal matrix composite using a viscoplastic constitutive theory

    Energy Technology Data Exchange (ETDEWEB)

    Sherwood, J.A.; Quimby, H.M. [Univ. of Massachusetts, Lowell, MA (United States). Dept. of Mechanical Engineering

    1996-04-01

    The thermomechanical behavior of a titanium aluminide metal matrix composite reinforced with silicon carbide fibers is computationally investigated to determine an optimum manufacturing process. The investigations are completed using the Ramaswamy-Stouffer constitutive model and the finite element method. Hold times at a given temperature were used in an effort to allow the residual stresses to relax. However, the subsequent temperature changes erased the benefit of such holds. Thermomechanical cycling was determined to be the optimum method for reducing the residual stress field after cooldown from consolidation.

  8. Properties and electronic structures of titanium aluminides-alumina composites from in-situ SHS process

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Y.F., E-mail: dinahyfsh@hotmail.com [School of Chemistry and Chemical Engineering, Guangxi University, Nanning, Guangxi 530000 (China); Key Laboratory of New Processing Technology for Nonferrous Metals and Materials, Ministry of Education, Guilin University of Technology, Guilin, Guangxi 541004 (China); Zou, Z.G., E-mail: zouzg@glite.edu.cn [Key Laboratory of New Processing Technology for Nonferrous Metals and Materials, Ministry of Education, Guilin University of Technology, Guilin, Guangxi 541004 (China); Xiao, Z.G.; Liu, K.; Long, F.; Wu, Y. [Key Laboratory of New Processing Technology for Nonferrous Metals and Materials, Ministry of Education, Guilin University of Technology, Guilin, Guangxi 541004 (China)

    2011-02-25

    Research highlights: {yields} In-situ SHS processing method plus vacuum hot-pressing process were applied. {yields} Mechanical and electronic properties and microscopic structures were studied. {yields} First principle pseudopotential plane-wave-based DFT calculations were performed. - Abstract: Titanium aluminides-alumina composite was synthesized by in-situ self-propagating high-temperature synthesis (SHS) method, followed by hot-pressing process. To understand the fundamental differences between the composite and A1{sub 2}O{sub 3} ceramic, a comparative study was carried out using first-principles plane-wave pseudopotential method based on density functional theory (DFT). XRD analysis of final products confirmed the formation of TiAl, A1{sub 2}O{sub 3} and a small amount of Ti{sub 3}Al phases in the composites and the reaction mechanisms of the process were proposed. SEM observation revealed that a two-phase ({gamma} + {alpha}{sub 2}) TiAl-Ti{sub 3}Al lamellar structure was formed, and the composites exhibited a homogeneous microstructure. Moreover, density of states (DOS), band structure, charge density difference and Mulliken population analysis showed that metallic, covalent and ionic bonding were produced at the interfaces of the composite. O-Al interface bonds showed more covalent character with respect to pure Al{sub 2}O{sub 3}. Therefore, interface combination of the composite was improved, making the composite tougher (a toughness as high as 7.9 MPa m{sup 1/2}) than monophase Al{sub 2}O{sub 3} ceramic.

  9. Material Removal and Specific Energy in the Dynamic Scratching of Gamma Titanium Aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H.; Lin, H.-T.; Wereszczak, A.A.

    2006-11-30

    Mechanical responses of three gamma titanium aluminides (TiAls) (denoted as Alloy A, Alloy B and Alloy C) subjected to dynamic scratching were studied by using a single-grit pendulum (rotating) scratch tester. The maximum depth of groove was {approx} 0.07 mm, and the scratch velocity was {approx} 1.0 m/s. Normal and tangential forces were monitored. The material removal mechanisms were examined using a scanning electron microscope (SEM) and the scratches were measured by using a laser profilometer. The mechanical properties of the tested TiAls were characterized by the instantaneous specific energy, scratch resistance and scratch hardness as related to the groove depth. Extensive thermal softening was observed in the dynamic scratch test of the TiAls, which facilitated both the detachment of developing chips and pile-up of material on side ridges. Sizable fractures were observed in the transverse direction in the tested TiAls; these fractures tended to participate in the chip formation, depending on the microstructure of the TiAl and the size of the scratch groove. Specific energy and scratch hardness are depth-dependent to various degrees for the TiAls tested. The material removal might be subjected to different mechanisms, but the overall material response can be effectively characterized by the HEM (Hwang, Evans and Malkin) model and the PSR (proportional specimen resistance) model. The depth-independent specific energy and scratch hardness can be used to screen candidate materials for the applications that are scratch-dominated versus impact-dominated. Among the three tested TiAls, the TiAl with larger colony or grain size exhibits a stronger capability of energy dissipation during material removal (higher depth-independent specific energy), while the TiAl with smaller colony size shows a higher resistance to indentation (higher depth-independent scratch hardness). The observations and conclusions in this study can serve as a base line for the further

  10. Material Removal and Specific Energy in the Dynamic Scratching of Gamma Titanium Aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hong [ORNL; Lin, Hua-Tay [ORNL; Wereszczak, Andrew A [ORNL

    2006-11-01

    Mechanical responses of three gamma titanium aluminides (TiAls) (denoted as Alloy A, Alloy B and Alloy C) subjected to dynamic scratching were studied by using a single-grit pendulum (rotating) scratch tester. The maximum depth of groove was ~ 0.07 mm, and the scratch velocity used was ~ 1.0 m/s. Normal and tangential forces were monitored. The material removal mechanisms were examined using a scanning electron microscope (SEM) and the scratches were measured by using a laser profilometer. The mechanical properties of the tested TiAls were characterized by the instantaneous specific energy, scratch resistance and scratch hardness as related to the depth of groove. Extensive thermal softening was observed in the dynamic scratch of the tested TiAls, which facilitated both the detachments of developing chips and the pile-ups of materials on side ridges. Sizable fractures were observed in the transverse direction on the tested TiAls; these fractures tended to participate in the chip formation, depending on the microstructure of the TiAl and the size of the scratch groove. Specific energy and scratch hardness are depth-dependent to various degrees for the tested TiAls. The materiel removal might be subjected to different mechanisms, but the overall response of materials can be effectively characterized by the HEM (Hwang, Evans and Malkin) model and the PSR (proportional specimen resistance) model. The obtained depth-independent specific energy and scratch hardness can be used to screen the candidate materials for the specific purpose depending on whether the application is scratch-dominant or impact-dominant. Among the three tested TiAls, the TiAl with larger colony or grain size exhibits a stronger capability of energy dissipation in the material loss or material removal (higher depth-independent specific energy), while the TiAl with smaller colony size show a higher resistance against the indentation (higher depth-independent scratch hardness). The observations and

  11. Experimental Study on Influence of Process Variables on Crater Dimensions in Micro- EDM of γ-Titanium Aluminide

    International Nuclear Information System (INIS)

    Mitra, S.; Paul, G.; Sarkar, S.; Nagahanumaiah

    2011-01-01

    In the present work the effect of different dielectric mediums in micro-EDM of γ-Titanium Aluminide alloy have been investigated. Experiments were conducted both in the absence (dry conditions) and in presence of dielectric (EDM oil).Circular craters were produced both in the presence and absence of dielectric fluid using varying micro-EDM process variables i.e. open circuit voltage, discharge capacitance, pulse frequency and pulse-on-time. Over cut was measured from optical microscope images using Image Analyzer software. Influences of process variables and optimal conditions for minimum over cut on crater dimensions were investigated. ANOVA test which shows that capacitance of RC circuit contributes significantly in crater formation followed by pulse frequency. Optical photographs exhibit that over cut are less in air medium compared to oil medium.

  12. Relationship of interaction of titanium aluminides with alloying elements as a basis for design of high-temperature alloys and composites

    International Nuclear Information System (INIS)

    Povarova, K.B.; Bannykh, O.A.; Antonova, A.V.

    2002-01-01

    One analyzed the available ternary phase diagrams of Ti-Al-AE where AE - alloying metal or metalloid. Nature of interaction of titanium aluminides, in particular, α 2 -Ti 3 Al, γ-TiAl and TiAl 3 with alloying elements (AE) in the uninvestigated systems was hypothesized with regard to the available binary and ternary phase diagrams and data on electron structure of AE. One determined that structure of Ti-Al-AE ternary phase diagrams, namely, position of domains of γ-TiAl and α 2 -Ti 3 Al base solid solutions, nature of substitution for AE positions in Ti or Al sublattices and position of (α 2 +γ)/γ domain boundary were governed by likeness or difference of electron structure of AE and of the substituted metal (Ti or Al) in titanium aluminide lattice and by value of dimension factor (difference of atomic radii of Al and Ti or Al). One analyzed promises offered by application of solid solution alloying and microalloying of aluminides by I-VIII group metals of the Periodic System [ru

  13. A Stochastic Reliability Model for Application in a Multidisciplinary Optimization of a Low Pressure Turbine Blade Made of Titanium Aluminide

    Directory of Open Access Journals (Sweden)

    Christian Dresbach

    Full Text Available Abstract Currently, there are a lot of research activities dealing with gamma titanium aluminide (γ-TiAl alloys as new materials for low pressure turbine (LPT blades. Even though the scatter in mechanical properties of such intermetallic alloys is more distinctive as in conventional metallic alloys, stochastic investigations on γ -TiAl alloys are very rare. For this reason, we analyzed the scatter in static and dynamic mechanical properties of the cast alloy Ti-48Al-2Cr-2Nb. It was found that this alloy shows a size effect in strength which is less pronounced than the size effect of brittle materials. A weakest-link approach is enhanced for describing a scalable size effect under multiaxial stress states and implemented in a post processing tool for reliability analysis of real components. The presented approach is a first applicable reliability model for semi-brittle materials. The developed reliability tool was integrated into a multidisciplinary optimization of the geometry of a LPT blade. Some processes of the optimization were distributed in a wide area network, so that specialized tools for each discipline could be employed. The optimization results show that it is possible to increase the aerodynamic efficiency and the structural mechanics reliability at the same time, while ensuring the blade can be manufactured in an investment casting process.

  14. Processing and application properties of silicon-doped titanium aluminides; Formgebungs- und Anwendungseigenschaften silizidhaltiger TiAl-Legierungen

    Energy Technology Data Exchange (ETDEWEB)

    Fanta, G. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Werkstofforschung

    2001-07-01

    Submicrocrystalline intermetallic/ceramic composites based on the system Ti-Al-Si are prepared by mechanical alloying and subsequent powder consolidation. Finely dispersed silicides prevent coarsening of the {gamma}-TiAl matrix during hot-forming. Therefore, the deformation temperatures can be reduced by about 200 C compared to conventional titanium aluminides. After a subsequent coarsening heat treatment, creep properties comparable to those of conventional TiAl based alloys (1.10{sup -9} s{sup -1} at 700 C) are achieved. This study demonstrates that microstructure design allows for favorable processing properties without compromises regarding the desired application properties. (orig.) [German] Zur Untersuchung des technischen Anwendungspotenzials submikrokristalliner Werkstoffe werden silizidhaltige {gamma}-TiAl-Basislegierungen durch Hochenergiemahlen und heissisostatisches Pressen hergestellt. Bei der industriellen Formgebung ermoeglicht die durch Silizide stabilisierte feine Mikrostruktur eine deutliche Temperaturabsenkung von 200 C im Vergleich zu den fuer Titanaluminide ueblichen Prozesstemperaturen. Nach einer anschliessend durchgefuehrten Gefuegeumwandlung werden Kriechgeschwindigkeiten gemessen, die mit 1.10{sup -9} s{sup -1} bei 700 C im Bereich der Werte schmelzmetallurgisch hergestellter TiAl-Legierungen liegen. Eine gezielte Mikrostrukturgestaltung ermoeglicht somit eine deutliche Verbesserung der Umformeigenschaften unter Beibehaltung der guenstigen Eigenschaften fuer Hochtemperaturanwendungen. (orig.)

  15. In situ high-energy X-ray diffraction study and quantitative phase analysis in the α + γ phase field of titanium aluminides

    International Nuclear Information System (INIS)

    Yeoh, LaReine A.; Liss, Klaus-Dieter; Bartels, Arno; Chladil, Harald; Avdeev, Maxim; Clemens, Helmut; Gerling, Rainer; Buslaps, Thomas

    2007-01-01

    Quantitative atomic structure and phase analysis in the titanium aluminide intermetallic system of composition Ti-45Al-7.5Nb-0.5C (at.%) was conducted in situ by use of high-energy X-ray diffraction from a synchrotron and evaluated using the Rietveld method, implementing a model for atomic order in the α-phase which describes the order to disorder transition α 2 → α at the eutectoid temperature. The order parameter exhibits unexpected behavior and is entangled with the competition of different kinetic processes

  16. Hydrostatic Compression Behavior and High-Pressure Stabilized β-Phase in γ-Based Titanium Aluminide Intermetallics

    Directory of Open Access Journals (Sweden)

    Klaus-Dieter Liss

    2016-07-01

    Full Text Available Titanium aluminides find application in modern light-weight, high-temperature turbines, such as aircraft engines, but suffer from poor plasticity during manufacturing and processing. Huge forging presses enable materials processing in the 10-GPa range, and hence, it is necessary to investigate the phase diagrams of candidate materials under these extreme conditions. Here, we report on an in situ synchrotron X-ray diffraction study in a large-volume press of a modern (α2 + γ two-phase material, Ti-45Al-7.5Nb-0.25C, under pressures up to 9.6 GPa and temperatures up to 1686 K. At room temperature, the volume response to pressure is accommodated by the transformation γ → α2, rather than volumetric strain, expressed by the apparently high bulk moduli of both constituent phases. Crystallographic aspects, specifically lattice strain and atomic order, are discussed in detail. It is interesting to note that this transformation takes place despite an increase in atomic volume, which is due to the high ordering energy of γ. Upon heating under high pressure, both the eutectoid and γ-solvus transition temperatures are elevated, and a third, cubic β-phase is stabilized above 1350 K. Earlier research has shown that this β-phase is very ductile during plastic deformation, essential in near-conventional forging processes. Here, we were able to identify an ideal processing window for near-conventional forging, while the presence of the detrimental β-phase is not present under operating conditions. Novel processing routes can be defined from these findings.

  17. Devising Strain Hardening Models Using Kocks–Mecking Plots—A Comparison of Model Development for Titanium Aluminides and Case Hardening Steel

    Directory of Open Access Journals (Sweden)

    Markus Bambach

    2016-08-01

    Full Text Available The present study focuses on the development of strain hardening models taking into account the peculiarities of titanium aluminides. In comparison to steels, whose behavior has been studied extensively in the past, titanium aluminides possess a much larger initial work hardening rate, a sharp peak stress and pronounced softening. The work hardening behavior of a TNB-V4 (Ti–44.5Al–6.25Nb–0.8Mo–0.1B alloy is studied using isothermal hot compression tests conducted on a Gleeble 3500 simulator, and compared to the typical case hardening steel 25MoCrS4. The behavior is analyzed with the help of the Kocks-Mecking plots. In contrast to steel the TNB-V4 alloy shows a non-linear course of θ (i.e., no stage-III hardening initially and exhibits neither a plateau (stage IV hardening nor an inflection point at all deformation conditions. The present paper describes the development and application of a methodology for the design of strain hardening models for the TNB-V4 alloy and the 25CrMoS4 steel by taking the course of the Kocks-Mecking plots into account. Both models use different approaches for the hardening and softening mechanisms and accurately predict the flow stress over a wide range of deformation conditions. The methodology may hence assist in further developments of more sophisticated physically-based strain hardening models for TiAl-alloys.

  18. Numerical study of crucial parameters in tilt casting for titanium aluminides

    Directory of Open Access Journals (Sweden)

    Hong Wang

    2011-08-01

    Full Text Available Numerical modeling of the tilt casting process for TiAl alloys was investigated to achieve a tranquil mould filling and TiAl castings free of defects. Titanium alloys are very reactive in molten state, so they are widely melted in cold crucible, e.g. the Induction Skull Melting (ISM furnace. Then the crucible holding the molten metal together with the mould is rotated to transfer the metal into the mould — ISM+ tilt casting. This paper emphasizes the effect of crucial parameters on mould filling and solidification of the castings during tilt casting. All crucial parameters, such as rotation rate, rotation profile, venting, initial mould temperature, casting orientation, feeder design, change of radius in 'T' junction and mould insulation have been discussed using numerical modeling data. Simulations were performed using a 3D CFD code PHYSICA implemented with front tracking, heat transfer algorithms and a turbulence model (which accounts for an advancing solid front.

  19. Effect of Energy Input on Microstructure and Mechanical Properties of Titanium Aluminide Alloy Fabricated by the Additive Manufacturing Process of Electron Beam Melting

    Directory of Open Access Journals (Sweden)

    Ashfaq Mohammad

    2017-02-01

    Full Text Available Titanium aluminides qualify adequately for advanced aero-engine applications in place of conventional nickel based superalloys. The combination of high temperature properties and lower density gives an edge to the titanium aluminide alloys. Nevertheless, challenges remain on how to process these essentially intermetallic alloys in to an actual product. Electron Beam Melting (EBM, an Additive Manufacturing Method, can build complex shaped solid parts from a given feedstock powder, thus overcoming the shortcomings of the conventional processing techniques such as machining and forging. The amount of energy supplied by the electron beam has considerable influence on the final build quality in the EBM process. Energy input is decided by the beam voltage, beam scan speed, beam current, and track offset distance. In the current work, beam current and track offset were varied to reflect three levels of energy input. Microstructural and mechanical properties were evaluated for these samples. The microstructure gradually coarsened from top to bottom along the build direction. Whereas higher energy favored lath microstructure, lower energy tended toward equiaxed grains. Computed tomography analysis revealed a greater amount of porosity in low energy samples. In addition, the lack of bonding defects led to premature failure in the tension test of low energy samples. Increase in energy to a medium level largely cancelled out the porosity, thereby increasing the strength. However, this trend did not continue with the high energy samples. Electron microscopy and X-ray diffraction investigations were carried out to understand this non-linear behavior of the strength in the three samples. Overall, the results of this work suggest that the input energy should be considered primarily whenever any new alloy system has to be processed through the EBM route.

  20. Making iron aluminides out of scrap

    OpenAIRE

    Borges, Doris Feijó Leão; Espinosa, Denise Crocce Romano; Schön, Cláudio Geraldo

    2014-01-01

    The abundance of iron and aluminum raw materials is often quoted as a strategic advantage of iron aluminides against other competing materials (not only stainless steels, but also nickel and titanium aluminides). These raw materials, however, are not only abundant in the form of ores in earth's crust, but also as scrap produced in the extensive technological activity associated with these base metals. The present work reports results of two prospective experiments designed for obtaining iron ...

  1. The effect of fiber microstructure on evolution of residual stresses in silicon carbide/titanium aluminide composites

    Science.gov (United States)

    Pindera, Marek-Jerzy; Freed, Alan D.

    1992-01-01

    This paper examines the effect of the morphology of the SCS6 silicon carbide fiber on the evolution of residual stresses in SiC/Ti composites. A micromechanics model based on the concentric cylinder concept is presented which is used to calculate residual stresses in a SiC/Ti composite during axisymmetric cooling by a spatially uniform temperature change. The silicon carbide fiber is modeled as a layered material with five distinct transversely isotropic and orthotropic, elastic layers, whereas the titanium matrix is taken to be isotropic, with temperature-dependent elastoplastic properties. The results arc compared with those obtained based on the assumption that the silicon carbide fiber is isotropic and homogeneous.

  2. Thermo-mechanical fatigue behaviour of the near-{gamma}-titanium aluminide alloy TNB-V5 under uniaxial and multiaxial loading

    Energy Technology Data Exchange (ETDEWEB)

    Brookes, Stephen Peter

    2009-12-19

    With increasing environmental awareness and the general need to economise on the use of fossil fuels, there is growing pressure for industry to produce lighter, more efficient, gas turbine engines. One such material that will help to achieve these improvements is the intermetallic gamma titanium aluminide ({gamma}-TiAl) alloy. At only half the density of current nickel-based superalloys its weight saving capability is highly desirable, however, its mechanical properties have not yet been fully explored especially, when it is to be considered for structural components in aeronautical gas turbine engines. Critical components in these engines typically experience large variations in temperatures and multiaxial states of stress under non-isothermal conditions. These stress states are known as tri-axial thermo-mechanical fatigue (TMF). The work presented here investigates the effects these multi-axial stresses, have on a {gamma}-TiAl, (Ti-45Al-5Nb-0.2B-0.2C) alloy under TMF conditions. The uniaxial, torsional and axialtorsional TMF behaviour of this {gamma}-TiAl alloy have been examined at 400 - 800 C with strain amplitudes ranging from 0.15% to 0.7%. The tests were conducted at both thermomechanical in-phase (IP) and out-of-phase (OP). Selected tests additionally contained a 180 seconds hold period. Fatigue lifetimes are strongly influenced by the strain amplitude, a small increase in amplitude reduces the lifetime considerably. The uniaxial IP tests showed significantly longer fatigue lifetimes than of all the tests performed. Torsional loading although have shorter fatigue lifetimes than the uniaxial IP loading they have longer fatigue lifetimes than the uniaxial OP loading. The non-proportional axial-torsional 90 degree OP test is most damaging which resulted in a shorter lifetime than the uniaxial OP test with the same Mises equivalent mechanical strain amplitude. A hold period at maximum temperatures reduced the lifetime for all tests regardless of the temperature

  3. Weldability of polycrystalline aluminides. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Fasching, A.A.; Burt, R.P.; Edwards, G.R.; David, S.A.

    1996-07-01

    When gas-tungsten arc welded, iron aluminides form a coarse fusion zone microstructure which is susceptible to hydrogen cracking. Magnetic arc oscillation and weld pool inoculation were implemented to refine the fusion zone microstructure in iron aluminide alloy FA-129 weldments. Magnetic arc oscillation effectively refined the fusion zone microstructure, and slow strain rate tensile tests showed fine-grained microstructures to be less susceptible to hydrogen cracking. However, magnetic arc oscillation was found to be suitable only for well-controlled fabrication environments. Weld pool inoculation offers a potentially more robust refinement method. Titanium inoculation was also shown to effectively refined the fusion zone microstructure, but weldment properties were not improved using this refinement method. The effect of titanium on the size, shape and distribution of the second phase particles in the fusion zone appears to be the cause of the observed decrease in weldment properties.

  4. Titanium: the innovators’ metal. Historical case studies tracing titanium process and product innovation [Journal Article

    CSIR Research Space (South Africa)

    Oosthuizen, SJ

    2011-11-01

    Full Text Available metal value chain. Both the Department of Science and Technology (DST) and the Department of Mineral Resources (DMR) have identified the creation of titanium metals production capabilities as a key growth area for South Africa. Using historical...

  5. Controlling fundamentals in high-energy high-rate pulsed power materials processing of powdered tungsten, titanium aluminides, and copper-graphite composites. Final technical report, 1 Jun 87-31 Aug 90

    Energy Technology Data Exchange (ETDEWEB)

    Persad, C.; Marcus, H.L.; Bourell, D.L.; Eliezer, Z.; Weldon, W.F.

    1990-10-01

    This study was conducted to determine the controlling fundamentals in the high-energy high-rate (1 MJ in 1s) processing of metal powders. This processing utilizes a large electrical current pulse to heat a pressurized powder mass. The current pulse was provided by a homopolar generator. Simple short cylindrical shapes were consolidated so as to minimize tooling costs. Powders were subjected to current densities of 5 kA/cm2 to 25 kA/cm2 under applied pressures ranging from 70 MPa to 500 MPa. Disks with diameters of 25 mm to 70 mm, and thicknesses of 1 mm to 10 mm were consolidated. Densities of 75% to 99% of theoretical values were obtained in powder consolidates of tungsten, titanium aluminides, copper-graphite, and other metal-ceramic composites. Extensive microstructural characterization was performed to follow the changes occuring in the shape and microstructure of the various powders. The processing science has at its foundation the control of the duration of elevated temperature exposure during powder consolidation.

  6. Compositions Comprising Nickel-Titanium, Methods Manufacture Thereof and Articles Comprising the Same

    Science.gov (United States)

    Glennon, Glenn N. (Inventor); DellaCorte, Christopher (Inventor)

    2016-01-01

    Disclosing herein is a method for manufacturing nickel-titanium compositions. The method includes disposing a powdered composition in a mold; the powdered composition comprising nickel and titanium; the titanium being present in an amount of about 38 to about 42 wt % and the nickel being present in an amount of about 58 to about 62 wt %; sintering the powdered composition to produce a sintered preform; compacting the preform; machining the preform to form an article; heat treating the article; the annealing being conducted at a temperature of about 1650.degree. F. to about 1900.degree. F. at a pressure of about 3 Torr to about 5 Kg-f/cm.sup.2 for a time period of about 10 minutes to about 5 hours; and quenching the article.

  7. Titanium

    Science.gov (United States)

    Woodruff, Laurel G.; Bedinger, George M.; Piatak, Nadine M.; Schulz, Klaus J.; DeYoung,, John H.; Seal, Robert R.; Bradley, Dwight C.

    2017-12-19

    Titanium is a mineral commodity that is essential to the smooth functioning of modern industrial economies. Most of the titanium produced is refined into titanium dioxide, which has a high refractive index and is thus able to impart a durable white color to paint, paper, plastic, rubber, and wallboard. Because of their high strength-to-weight ratio and corrosion resistance, titanium metal and titanium metal alloys are used in the aerospace industry as well as for welding rod coatings, biological implants, and consumer goods.Ilmenite and rutile are currently the principal titanium-bearing ore minerals, although other minerals, including anatase, perovskite, and titanomagnetite, could have economic importance in the future. Ilmenite is currently being mined from two large magmatic deposits hosted in rocks of Proterozoic-age anorthosite plutonic suites. Most rutile and nearly one-half of the ilmenite produced are from heavy-mineral alluvial, fluvial, and eolian deposits. Titanium-bearing minerals occur in diverse geologic settings, but many of the known deposits are currently subeconomic for titanium because of complications related to the mineralogy or because of the presence of trace contaminants that can compromise the pigment production process.Global production of titanium minerals is currently dominated by Australia, Canada, Norway, and South Africa; additional amounts are produced in Brazil, India, Madagascar, Mozambique, Sierra Leone, and Sri Lanka. The United States accounts for about 4 percent of the total world production of titanium minerals and is heavily dependent on imports of titanium mineral concentrates to meet its domestic needs.Titanium occurs only in silicate or oxide minerals and never in sulfide minerals. Environmental considerations for titanium mining are related to waste rock disposal and the impact of trace constituents on water quality. Because titanium is generally inert in the environment, human health risks from titanium and titanium

  8. Corrosion of carbon-alloyed iron aluminides

    Indian Academy of Sciences (India)

    Unknown

    alloyed intermetallics were susceptible to galvanic corrosion, due to the presence of carbides. Keywords. Corrosion; iron aluminides; Fe3Al; potentiodynamic polarization. 1. Introduction. Ordered intermetallic alloys based on iron aluminides of.

  9. Surface grinding of intermetallic titanium aluminides

    CERN Document Server

    Gröning, Holger Andreas

    2014-01-01

    A deductive kinematic model of creep-feed and speed-stroke grinding processes is developed to identify possibilities to reduce the energy introduced into the workpiece. By computer tomography analysis and tactile measurements of the grinding wheel the pore volume and the static cutting edge number are determined and included in the model. Based on the kinematic model and the grinding wheel characteristics an analytical evaluation of the specific grinding energy for speed-stroke and creep-feed grinding is carried out. The deducted process design is evaluated in experimental investigations. The

  10. Corrosion performance of iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.

    1993-03-01

    Iron aluminides are being developed for use as structural materials and/or cladding alloys in fossil energy systems. Extensive development has been in progress on Fe[sub 3]Al-based alloys to improve the engineering ductility of these alloys. This paper describes results from the ongoing program to evaluate the corrosion performance of these alloys. The experimental program at Argonne National Laboratory involvesthermogravimetric analyses of alloys exposed to environments that simulate coal gasification and fluidized-bed combustion. Experiments were conducted at 650--1000[degrees]C in simulated oxygen/sulfur gas mixtures. In addition, oxidation/sulfidation behavior of several alumina-forming Fe-Al and Fe-Cr-Ni-Al alloys was determined for comparison with the corrosion rates obtained on iron aluminides. Other aspects of the program are corrosion evaluation of the aluminides in the presence of HC1-containing gases and in the presence of slag from a slogging gasifier. Results are used to establish threshold Al levels in the alloys for development of protective alumina scales. Thermal cycling tests are used to examine the spalling resistance of the scales.

  11. Corrosion performance of iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.

    1993-03-01

    Iron aluminides are being developed for use as structural materials and/or cladding alloys in fossil energy systems. Extensive development has been in progress on Fe{sub 3}Al-based alloys to improve the engineering ductility of these alloys. This paper describes results from the ongoing program to evaluate the corrosion performance of these alloys. The experimental program at Argonne National Laboratory involvesthermogravimetric analyses of alloys exposed to environments that simulate coal gasification and fluidized-bed combustion. Experiments were conducted at 650--1000{degrees}C in simulated oxygen/sulfur gas mixtures. In addition, oxidation/sulfidation behavior of several alumina-forming Fe-Al and Fe-Cr-Ni-Al alloys was determined for comparison with the corrosion rates obtained on iron aluminides. Other aspects of the program are corrosion evaluation of the aluminides in the presence of HC1-containing gases and in the presence of slag from a slogging gasifier. Results are used to establish threshold Al levels in the alloys for development of protective alumina scales. Thermal cycling tests are used to examine the spalling resistance of the scales.

  12. PERSPECTIVE TECHNOLOGIES OF THERMAL HARDENING OF LARGE-SIZE ARTICLES OF TWO-PHASE TITANIUM ALLOYS

    Directory of Open Access Journals (Sweden)

    V. N. Fedulov

    2005-01-01

    Full Text Available The article is dedicated to the development and industrial assimilation of the fundamentally new methods of thermal strengthening of large articles out of hardenable titanic alloys.

  13. Zirconium influence on microstructure of aluminide coatings ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 36; Issue 6. Zirconium influence on microstructure of aluminide coatings deposited on nickel substrate by CVD method. Jolanta Romanowska Maryana ... The coatings with and without zirconium were deposited by CVD method. The cross-section chemical composition ...

  14. Making iron aluminides out of scrap

    Directory of Open Access Journals (Sweden)

    Doris Feijó Leão Borges

    2014-04-01

    Oxidation tests at the temperature range of 800–1100 °C under air were performed to demonstrate that these alloys show similar behavior as the ones obtained using conventional processing routes. The results are discussed concerning the viability of this low-cost processing route for the industrial production of iron aluminides.

  15. Large Scale Evaluation fo Nickel Aluminide Rolls

    Energy Technology Data Exchange (ETDEWEB)

    None

    2005-09-01

    This completed project was a joint effort between Oak Ridge National Laboratory and Bethlehem Steel (now Mittal Steel) to demonstrate the effectiveness of using nickel aluminide intermetallic alloy rolls as part of an updated, energy-efficient, commercial annealing furnace system.

  16. Zirconium influence on microstructure of aluminide coatings ...

    Indian Academy of Sciences (India)

    Abstract. Influence of Zr on the microstructure and phase characteristics of aluminide diffusion coatings deposited on the nickel substrate has been investigated in this study. The coatings with and without zirconium were deposited by CVD method. The cross-section chemical composition investigations revealed that during ...

  17. Influence of high-strain rate and temperature on the mechanical behavior of Nl-, Fe-, and Ti- based aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Gray, G.T. III

    1996-09-01

    The majority of the strength characterization studies on ordered intermetallics have concentrated on the assessment of strength and work-hardening at conventional strain rates. Although the influence of strain rate on the structure/property relationships of pure nickel, iron, and titanium and a variety of their alloys have been extensively studied, the effect of strain rate on the stress-strain response of Ni-, Fe-, and Ti-based aluminides remains poorly understood. Dynamic constitutive behavior is however relevant to high speed impact performance of these materials such as during foreign object damage in aerospace applications, high-rate forging, and localized deformation behavior during machining. The influence of strain rate, varied between 0.001 and 10{sup 4} s{sup -1}, and temperatures, between 77 & 800K, on the compressive mechanical behavior of Ni{sub 3}A1, NiAl, Fe{sub 3}Al, Fe-40Al-0.1B, Ti-24Al-11Nb, and Ti-48Al-2Cr-2Nb will be presented. In this paper the influence of strain rate on the anomalous temperature dependency of the flow stresses in these aluminides will be reviewed and compared between aluminides. The rate sensitivity and work hardening of each aluminide will be discussed as a function of strain rate and temperature and contrasted to each other and to the values typical for their respective disordered base metals. 66 refs., 16 figs., 2 tabs.

  18. Aqueous Corrosion Characteristics of Nickel Aluminides

    International Nuclear Information System (INIS)

    Kim, Jung Gu

    1996-01-01

    The aqueous corrosion characteristics of three nickel aluminides were studied by using (a) immersion corrosion test and (b) cyclic anodic polarization measurements. The immersion tests were conducted in 15 different solutions at 25 .deg. C and 95 .deg. C. The nickel aluminides were found to have good corrosion resistance in inorganic acids, organic acids and basic solutions 25 .deg. C except at a higher concentration of hydrochloric acid in ferric chloride solution at the temperature. All three nickel aluminides were suitably resistant to corrosion in the organic acids (oxalic acid, acetic acid), sodium chloride solution, and bases (sodium hydoxide, ammonium hydroxide) at 95 .deg. C. The cyclic anodic polarization curves were developed in N 2 -deaerated solution at 25 .deg. C and 95 .deg. C. In addition, open-circuit corrosion potentials were determined for the solutions in the aerated condition at 25 .deg. C to compare with the anodic curves. At 25 .deg. C, although all materials exhibited active-passive behavior in all solutions except the hydrofluoric acid, at E corr (aerated), passive corrosion was only indicated for the acetic acid, sodium hydroxide, and sodium chloride solutions. Nevertheless, in all cases, the predicted dissolution rates were consistent with immersion test results. Hysteresis loops indicating susceptibility to localized corrosion were observed in 0.6M sodium chloride(pH=7) solution. At 95 .deg. C, active-passive behavior was demonstrated in the acetic acid, sodium chloride, and to a limited extent in the nitric acid: but only active behavior was shown in the sulfuric and hydrofluoric acids. From the above results, it was noted that anodic dissolution of nickel aluminides significantly increased with increasing temperature and that the Cr-containing compositions had better corrosion resistance in several solutions than the Cr-free composition. Prior manufacturing procedures, i.e., casting and powder metallurgy processes did not appear to

  19. Article

    African Journals Online (AJOL)

    - formed consent from study participants.8. More than 500 journals around the world have responded and adopted the requirements of the ICMJE.9 As a result the number of articles reporting informed consent in clinical trials increased from.

  20. ARTICLES

    African Journals Online (AJOL)

    ARTICLES. NEONATAL VITAMIN A. SUPPLEMENTATION. Jean Humphrey. Vitamin A deficiency is a major public health problem throughout the developing world, affecting an estimated 124 million young children and accounting for more than 1 million child deaths each year.' A meta-analysis of eight controlled.

  1. ARTICLES

    African Journals Online (AJOL)

    ARTICLES. ,i. INTRAVASCULAR CATHETER. SEPSIS. Mervyn Mer. Intravascular devices are an integral component of modern-day medical practice. They are used to administer intravenous fluids, medications, blood products and parenteral nutrition. In addition, they serve as a valuable monitor of the haemo- dynamic ...

  2. Article

    African Journals Online (AJOL)

    I also thank Professor Julia Sloth-Nielsen of the Faculty of Law, UWC, and Mr Lukas Muntingh of CSPRI for their valuable comments on the. 2007 version of this article. OSF-SA and Ford Foundation's funding to. CSPRI and CLC is acknowledged. The usual caveats apply. References. 1. For example, there was much interest ...

  3. Article

    African Journals Online (AJOL)

    FUTLIB12

    E-resources have enhanced the learning process to students by providing relevant information for their academic activities. Use of Electronic Information Resources by Postgraduate. Students of Universities in North Central Nigeria. Article https://dx.doi.org/10.4314/iijikm.v8i3.6. Information Impact: Journal of Information and.

  4. articles

    African Journals Online (AJOL)

    2011-12-04

    Dec 4, 2011 ... Google Scholar, African Journals Online (AJOL), and archives of the Nigerian Journal of Psychiatry. Six articles included content relating to age of the child at first presentation to orthodox clinical practice and symptoms at presentation related to expressive language ability and therefore fulfilled the inclusion.

  5. Article

    African Journals Online (AJOL)

    FDB

    Institutional repository (IR), therefore, is any digital repository that is set up to capture, manage, preserve and distribute the intellectual ... Nigerian Universities. Article https://dx.doi.org/10.4314/iijikm.v8i3.8. Information Impact: Journal of Information and. Knowledge Management. 2017, Vol. 8 (3) Pg 83 - 102. ISSN: 2141 ...

  6. Characteristics of laser In-situ alloyed titanium aluminides coatings

    CSIR Research Space (South Africa)

    Tlotleng, Monnamme

    2017-01-01

    Full Text Available to study the in-situ alloying of the elemental Ti and Al using laser metal deposition (LMD) process. The effects of laser power on the microstructure evolution, composition and micro-hardness were evaluated on the as-produced TiAl coatings. The results...

  7. Hydrogen enhanced thermal fatigue of y-titanium aluminide

    NARCIS (Netherlands)

    Dunfee, William; Gao, Ming; Wei, Robert P.; Wei, W.

    1995-01-01

    A study of hydrogen enhanced thermal fatigue cracking was carried out for a gamma-based Ti-48Al-2Cr alloy by cycling between room temperature and 750 or 900 °C. The results showed that hydrogen can severely attack the gamma alloy, with resulting lifetimes as low as three cycles, while no failures

  8. Joining silicon nitride to FA-129 iron aluminide

    Science.gov (United States)

    Brochu, Mathieu

    Joints between dissimilar materials are characterized particularly by compositional gradients and microstructural changes, which yield large variations in chemical, physical and mechanical properties across the joint. The joining of dissimilar materials is therefore more complex than the joining of similar materials. In this project, the joining procedure, from the interaction between the different components in a joint to the determination of the mechanical properties was applied to the Si3N4/FA-129 system. This iron aluminide intermetallic alloy (FA-129), was developed by Oak Ridge National Laboratories (ORNL) to have high temperature properties with good room temperature ductility. This intermetallic is replacing high strength ferritic stainless steel (SS) in moderate strength applications due to cost and property reasons. Joints between SS and Si3N4 are already used industrially and this project was to evaluate the potential to replace these Si3N 4/SS joints by those of Si3N4/FA-129. Broadly stated, the results obtained during this project are as follows: (I) The E2 energy for Si3N4 ceramic was calculated to be 3.01 keV. (II) The wetting of iron aluminide alloy by copper has been achieved and the spreading and reaction kinetics are influenced by the presence of Cr as alloying element. (III) The penetration and decohesion of the FA-129 microstructure is significantly reduced by the utilization of a Cu alloy containing a high titanium concentration. (IV) An active brazing alloy containing a high active element content can be fabricated by an electroless deposition technique. (V) The melting behavior of the powder was characterized and complete melting occurs in a multi-step process at different temperatures, which are a function of the heating rate. (VI) The strength of joint produced by brazing Si3N4 to itself using the composite powder reached 400 MPa. (VII) Direct brazing of Si 3N4 to FA-129 was shown to be unsuccessful and therefore a soft Cu interlayer was

  9. Method of manufacturing iron aluminide by thermomechanical processing of elemental powders

    Science.gov (United States)

    Deevi, Seetharama C.; Lilly, Jr., A. Clifton; Sikka, Vinod K.; Hajaligol, Mohammed R.

    2000-01-01

    A powder metallurgical process of preparing iron aluminide useful as electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 20 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.05% Zr or ZrO.sub.2 stringers extending perpendicular to an exposed surface of the heating element, .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Zr, .ltoreq.1% C, .ltoreq.0.1% B, .ltoreq.30% oxide dispersoid and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1 % rare earth metal, .ltoreq.1% oxygen, and/or .ltoreq.3% Cu. The process includes forming a mixture of aluminum powder and iron powder, shaping the mixture into an article such as by cold rolling the mixture into a sheet, and sintering the article at a temperature sufficient to react the iron and aluminum powders and form iron aluminide. The sintering can be followed by hot or cold rolling to reduce porosity created during the sintering step and optional annealing steps in a vacuum or inert atmosphere.

  10. Physical metallurgy of nickel aluminides

    Indian Academy of Sciences (India)

    A description of the important physical metallurgy aspects of Ni$_3Al and NiAl encompassing structure, crystallographic defects, slip systems and phase stability has been presented in this article. The microstructures generated in the two alloys by conventional as well as novel processing techniques have been discussed.

  11. Microstructural effects on the creep and crack propagation behaviors of γ-Ti aluminide alloy

    International Nuclear Information System (INIS)

    Lupinc, V.; Onofrio, G.; Nazmy, M.; Staubli, M.

    1999-01-01

    Gamma titanium aluminides class of materials possess several unique physical and mechanical properties. These characteristics can be attractive for specific industrial applications. By applying different heat treatment schedules one can change the microstructural features of this class of materials. In the present investigation, two heat treatment schedules were used to produce two different microstructures, duplex (D) and nearly lamellar (NL) in the cast and HIP'ed Ti-47Al-2W-0.5Si alloy. The tensile strength and creep behavior, in the 700--850 C temperature range, of this alloy have been determined and correlated to the corresponding microstructures. In addition, the fatigue crack propagation behavior in this alloy has been studied at different temperatures. The results on the creep behavior showed that the alloy with nearly lamellar microstructure has a strongly improved creep strength as compared with that of the duplex microstructure

  12. Compatibility of aluminide-coated Hastelloy x and Inconel 617 in a simulated gas-cooled reactor environment

    International Nuclear Information System (INIS)

    Chin, J.; Johnson, W.R.; Chen, K.

    1982-03-01

    Commercially prepared aluminide coatings on Hastelloy X and Inconel 617 substrates were exposed to controlled-impurity helium at 850 0 and 950 0 C for 3000 h. Optical and scanning electron (SEM) microscopy, electron microprobe profiles, and SEM X-ray mapping were used to evaluate and compare exposed and unexposed control samples. Four coatings were evaluated: aluminide, aluminide with platinum, aluminide with chromium, and aluminide with rhodium. With extended time at elevated temperature, nickel diffused into the aluminide coatings to form epsilon-phase (Ni 3 Al). This diffusion was the primary cause of porosity formation at the aluminide/alloy interface

  13. Advances in titanium alloys

    International Nuclear Information System (INIS)

    Seagle, S.R.; Wood, J.R.

    1993-01-01

    As described above, new developments in the aerospace market are focusing on higher temperature alloys for jet engine components and higher strength/toughness alloys for airframe applications. Conventional alloys for engines have reached their maximum useful temperature of about 1000 F (540 C) because of oxidation resistance requirements. IMI 834 and Ti-1100 advanced alloys show some improvement, however, the major improvement appears to be in gamma titanium aluminides which could extend the maximum usage temperature to about 1500 F (815 C). This puts titanium alloys in a competitive position to replace nickel-base superalloys. Advanced airframe alloys such as Ti-6-22-22S, Beta C TM , Ti-15-333 and Ti-10-2-3 with higher strength than conventional Ti-6-4 are being utilized in significantly greater quantities, both in military and commercial applications. These alloys offer improved strength with little or no sacrifice in toughness and improved formability, in some cases. Advanced industrial alloys are being developed for improved corrosion resistance in more reducing and higher temperature environments such as those encountered in sour gas wells. Efforts are focused on small precious metal additions to optimize corrosion performance for specific applications at a modest increase in cost. As these applications develop, the usage of titanium alloys for industrial markets should steadily increase to approach that for aerospace applications. (orig.)

  14. Extended life aluminide fuel. Final report

    International Nuclear Information System (INIS)

    Miller, L.G.; Beeston, J.M.

    1986-06-01

    As the price of fuel fabrication, shipment of both new and spent fuel, and fuel reprocessing continue to rise at a rapid rate, researchers look for alternate methods to keep reactor fuel costs within their limited funding. Extended fuel element lifetimes, without jeopardizing reactor safety, can reduce fuel costs by up to a factor of two. The Extended Life Aluminide (ELAF) program was started at the Idaho National Engineering Laboratory (INEL) as a joint project of the United States Department of Energy (DOE), the University of Missouri, and the Massachusetts Institute of Technology research reactors. Fuel plates of Advanced Test Reactor (ATR) type construction were fabricated at Atomics International and irradiated in the ATR at the INEL. Four fuel matrix compositions were tested (i.e., 50 vol% UAl/sub x/ cores for reference, and 40, 45 and 50 vol% UAl 2 cores). The 50 vol% UAl 2 cores contained up to 3 grams U-235 per cm 3 of core. Three plates of each composition were irradiated to peak burnup levels of 3 x 10 21 fission/cm 3 of core. The only observed damage was due to external corrosion at similar rates experienced by UAl/sub x/ fuel elements in test reactors

  15. Numerical modelling of the tilt casting processes of titanium alumindes

    OpenAIRE

    Wang, Hong

    2008-01-01

    This research has investigated the modelling and optimisation of the tilt casting process of Titanium Aluminides (TiAl). This study is carried out in parallel with the experimental research undertaken in IRC at the University of Birmingham. They propose to use tilt casting inside a vacuum chamber and attempt to combine this tilt casting process with Induction Skull Melting (ISM). A totally novel process is developing for investment casting, which is suitable for casting gamma TiAl.\\ud \\ud As ...

  16. Article Article

    African Journals Online (AJOL)

    2010-08-09

    Aug 9, 2010 ... Article. Over the past two decades, all eight South African medical schools (see. Map (Fig. 1) and Table I) have undertaken renewal of their MB ChB educational ... and Training of Doctors in South Africa document, the five-star doctor ..... perceived lack of rewards for teaching and sense of the importance.

  17. Titanium Metal Powder Production by the Plasma Quench Process

    Energy Technology Data Exchange (ETDEWEB)

    R. A. Cordes; A. Donaldson

    2000-09-01

    The goals of this project included the scale-up of the titanium hydride production process to a production rate of 50 kg/hr at a purity level of 99+%. This goal was to be achieved by incrementally increasing the production capability of a series of reactor systems. This methodic approach was designed to allow Idaho Titanium Technologies to systematically address the engineering issues associated with plasma system performance, and powder collection system design and performance. With quality powder available, actual fabrication with the titanium hydride was to be pursued. Finally, with a successful titanium production system in place, the production of titanium aluminide was to be pursued by the simultaneously injection of titanium and aluminum precursors into the reactor system. Some significant accomplishments of the project are: A unique and revolutionary torch/reactor capable of withstanding temperatures up to 5000 C with high thermal efficiency has been operated. The dissociation of titanium tetrachloride into titanium powder and HC1 has been demonstrated, and a one-megawatt reactor potentially capable of producing 100 pounds per hour has been built, but not yet operated at the powder level. The removal of residual subchlorides and adsorbed HC1 and the sintering of powder to form solid bodies have been demonstrated. The production system has been operated at production rates up to 40 pounds per hour. Subsequent to the end of the project, Idaho Titanium Technologies demonstrated that titanium hydride powder can indeed be sintered into solid titanium metal at 1500 C without sintering aids.

  18. Investigation of the microtructure of platinum-modified aluminide coatings

    Czech Academy of Sciences Publication Activity Database

    Pedraza, F.; Kennedy, A.D.; Kopeček, Jaromír; Moretto, P.

    2007-01-01

    Roč. 200, - (2007), s. 4032-4039 ISSN 0257-8972 Grant - others:Marie Curie Fellowship (ORDICO)(XE) G4TR-CT-2000-0042 and G4RD-CT-2000-00319 Institutional research plan: CEZ:AV0Z10100520 Keywords : single crystal nickel superalloy * out-of pack platinum-modified aluminide coating * single phase Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.678, year: 2007

  19. Titanium allergy: A literature review

    Directory of Open Access Journals (Sweden)

    Manish Goutam

    2014-01-01

    Full Text Available Titanium has gained immense popularity and has successfully established itself as the material of choice for dental implants. In both medical and dental fields, titanium and its alloys have demonstrated success as biomedical devices. Owing to its high resistance to corrosion in a physiological environment and the excellent biocompatibility that gives it a passive, stable oxide film, titanium is considered the material of choice for intraosseous use. There are certain studies which show titanium as an allergen but the resources to diagnose titanium sensivity are very limited. Attention is needed towards the development of new and precise method for early diagnosis of titanium allergy and also to find out the alternative biomaterial which can be used in place of titanium. A review of available articles from the Medline and PubMed database was done to find literature available regarding titanium allergy, its diagnosis and new alternative material for titanium.

  20. Titanium allergy: a literature review.

    Science.gov (United States)

    Goutam, Manish; Giriyapura, Chandu; Mishra, Sunil Kumar; Gupta, Siddharth

    2014-11-01

    Titanium has gained immense popularity and has successfully established itself as the material of choice for dental implants. In both medical and dental fields, titanium and its alloys have demonstrated success as biomedical devices. Owing to its high resistance to corrosion in a physiological environment and the excellent biocompatibility that gives it a passive, stable oxide film, titanium is considered the material of choice for intraosseous use. There are certain studies which show titanium as an allergen but the resources to diagnose titanium sensivity are very limited. Attention is needed towards the development of new and precise method for early diagnosis of titanium allergy and also to find out the alternative biomaterial which can be used in place of titanium. A review of available articles from the Medline and PubMed database was done to find literature available regarding titanium allergy, its diagnosis and new alternative material for titanium.

  1. A Review on the Properties of Iron Aluminide Intermetallics

    Directory of Open Access Journals (Sweden)

    Mohammad Zamanzade

    2016-01-01

    Full Text Available Iron aluminides have been among the most studied intermetallics since the 1930s, when their excellent oxidation resistance was first noticed. Their low cost of production, low density, high strength-to-weight ratios, good wear resistance, ease of fabrication and resistance to high temperature oxidation and sulfurization make them very attractive as a substitute for routine stainless steel in industrial applications. Furthermore, iron aluminides allow for the conservation of less accessible and expensive elements such as nickel and molybdenum. These advantages have led to the consideration of many applications, such as brake disks for windmills and trucks, filtration systems in refineries and fossil power plants, transfer rolls for hot-rolled steel strips, and ethylene crackers and air deflectors for burning high-sulfur coal. A wide application for iron aluminides in industry strictly depends on the fundamental understanding of the influence of (i alloy composition; (ii microstructure; and (iii number (type of defects on the thermo-mechanical properties. Additionally, environmental degradation of the alloys, consisting of hydrogen embrittlement, anodic or cathodic dissolution, localized corrosion and oxidation resistance, in different environments should be well known. Recently, some progress in the development of new micro- and nano-mechanical testing methods in addition to the fabrication techniques of micro- and nano-scaled samples has enabled scientists to resolve more clearly the effects of alloying elements, environmental items and crystal structure on the deformation behavior of alloys. In this paper, we will review the extensive work which has been done during the last decades to address each of the points mentioned above.

  2. Filler metal alloy for welding cast nickel aluminide alloys

    Science.gov (United States)

    Santella, Michael L.; Sikka, Vinod K.

    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.

  3. A comparative study on laser processing of commercially available titanium aluminide (TI-48AL-2CR-2NB) and in-situ alloying of titanium aluminide

    CSIR Research Space (South Africa)

    Hoosain, Shaik E

    2017-11-01

    Full Text Available -phase composition of Ti-48Al [4,5,6,8]. The best ductility observed in Ti-48Al was hypothesised to be governed by an optimum volume ratio of the alpha and gamma phases, below which grain growth becomes pronounced when heat treated in the α+ γ phase field..., and above which the brittle alpha-2 phase eliminates the beneficial effect of the refined microstructure [7,9,10]. Additions of chromium increase the ductility of two phase gamma alloys but have no obvious effect in single-phase alloys containing more than...

  4. Titanium production for aerospace applications

    Directory of Open Access Journals (Sweden)

    Vinicius A. R. Henriques

    2009-01-01

    Full Text Available Titanium parts are ideally suited for advanced aerospace systems because of their unique combination of high specific strength at both room temperature and moderately elevated temperature, in addition to excellent general corrosion resistance. The objective of this work is to present a review of titanium metallurgy focused on aerospace applications, including developments in the Brazilian production of titanium aimed at aerospace applications. The article includes an account of the evolution of titanium research in the Brazilian Institute (IAE/CTA and the current state-of-art of titanium production in Brazil.

  5. Formation of electrically insulating coatings on aluminided vanadium-base alloys in liquid lithium

    International Nuclear Information System (INIS)

    Park, J.H.; Dragel, G.

    1993-01-01

    Aluminide coatings were produced on vanadium and vanadium-base alloys by exposure of the materials to liquid lithium that contained 3-5 at.% dissolved aluminum in sealed capsules at temperatures between 775 and 880 degrees C. Reaction of the aluminide layer with dissolved nitrogen in liquid lithium provides a means of developing an in-situ electrical insulator coating on the surface of the alloys. The electrical resistivity of A1N coatings on aluminided V and V-20 wt.% Ti was determined in-situ

  6. Titanium ; dream new material

    International Nuclear Information System (INIS)

    Lee, Yong Tae; Kim Seung Eon; Heoon, Yong Taek; Jung, Hui Won

    2001-11-01

    The contents of this book are history of Titanium, present situation of Titanium industry, property of Titanium alloy, types of it, development of new alloy of Titanium smelting of Titanium, cast of Titanium and heat treatment of Titanium, Titanium alloy for plane, car parts, biological health care, and sport leisure and daily life, prospect, and Titanium industrial development of Titanium in China.

  7. Oxide Dispersion Strengthened Iron Aluminide by CVD Coated Powders

    Energy Technology Data Exchange (ETDEWEB)

    Asit Biswas Andrew J. Sherman

    2006-09-25

    This I &I Category2 program developed chemical vapor deposition (CVD) of iron, aluminum and aluminum oxide coated iron powders and the availability of high temperature oxidation, corrosion and erosion resistant coating for future power generation equipment and can be used for retrofitting existing fossil-fired power plant equipment. This coating will provide enhanced life and performance of Coal-Fired Boilers components such as fire side corrosion on the outer diameter (OD) of the water wall and superheater tubing as well as on the inner diameter (ID) and OD of larger diameter headers. The program also developed a manufacturing route for readily available thermal spray powders for iron aluminide coating and fabrication of net shape component by powder metallurgy route using this CVD coated powders. This coating can also be applid on jet engine compressor blade and housing, industrial heat treating furnace fixtures, magnetic electronic parts, heating element, piping and tubing for fossil energy application and automotive application, chemical processing equipment , heat exchanger, and structural member of aircraft. The program also resulted in developing a new fabrication route of thermal spray coating and oxide dispersion strengthened (ODS) iron aluminide composites enabling more precise control over material microstructures.

  8. PROTECTIVE LAYERS OF IRON AND NICKEL ALUMINIDES ON STEEL

    Directory of Open Access Journals (Sweden)

    Milena Voděrová

    2013-07-01

    Full Text Available Intermediary phases Ni-Al and Fe-Al are promising materials due to their superior properties such as hardness and good resistance against oxidation at high temperatures. Moreover, Fe-Al phases are resistant in sulphur - containing atmospheres. Because of these characteristics, the above mentioned intermetallic phases seem to be prospective for the use in many technical applications such as energetics, chemical or automotive industry in a form of a bulk material or coatings. Presently, the protective aluminide layer is usually prepared by thermal spraying. Nevertheless, this method is not suitable for complex-shaped components. Therefore, the aim of this work was to find an alternative way to prepare layers consisting of nickel or iron aluminides by other technique than thermal spraying. At first, carbon steel samples were coated using galvanic or electroless nickel plating. Coated samples were subsequently submerged into molten aluminium at various temperatures and process durations. The influence of the temperature and duration on the intermetallic phase growth was studied by scanning electron and light microscopy. Thickness and microhardness of the intermetallic layer was also measured.

  9. PROTECTIVE LAYERS OF IRON AND NICKEL ALUMINIDES ON STEEL

    Directory of Open Access Journals (Sweden)

    Milena Voderova

    2013-05-01

    Full Text Available Intermediary phases Ni-Al and Fe-Al are promising materials due to their superior properties such as hardness and good resistance against oxidation at high temperatures. Moreover, Fe-Al phases are resistant in sulphur - containing atmospheres. Because of these characteristics, the above mentioned intermetallic phases seem to be prospective for the use in many technical applications such as energetics, chemical or automotive industry in a form of a bulk material or coatings. Presently, the protective aluminide layer is usually prepared by thermal spraying. Nevertheless, this method is not suitable for complex-shaped components. Therefore, the aim of this work was to find an alternative way to prepare layers consisting of nickel or iron aluminides by other technique than thermal spraying. At first, carbon steel samples were coated using galvanic or electroless nickel plating. Coated samples were subsequently submerged into molten aluminium at various temperatures and process durations. The influence of the temperature and duration on the intermetallic phase growth was studied by scanning electron and light microscopy. Thickness and microhardness of the intermetallic layer was also measured.

  10. Titanium oxide fever

    International Nuclear Information System (INIS)

    De Jonge, D.; Visser, J.

    2012-01-01

    One measure to improve air quality is to apply photo-catalytic substances that capture NOx onto the road surface or onto baffle boards alongside the roads. The effect of titanium oxide containing clinkers with coating was discussed in the report 'Demonstration project of air-purifying pavement in Hengelo, The Netherlands' that was published in May 2011. This article examines the way in which the effectiveness of this study was determined. Can titanium oxide containing clinkers and coatings indeed capture NOx?. [nl

  11. Titanium 2013

    Science.gov (United States)

    2014-01-01

    Titanium is the ninth most abundant element in the earth's crust and can be found in nearly all rocks and sediments. It is a lithophile element with a strong affinity for oxygen and is not found as a pure metal in nature. Titanium was first isolated as a pure metal in 1910, but it was not until 1948 that the metal was produced commercially using the Kroll process (named after its developer, William Kroll) to reduce titanium tetrachloride with magnesium to produce titanium metal.

  12. Current status of research and development on nickel and iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.T.; George, E.P.; McKamey, C.G.

    1993-12-01

    This paper provides a comprehensive review of current status of research and development on nickel and iron aluminides based on Ni{sub 3}Al, NiAl, Fe{sub 3}Al and FeAl. These aluminides possess attractive properties for elevated-temperature structural use; however, brittle fracture and poor fracture resistance have limited their use as engineering materials in many cases. in recent years, considerable effort has been devoted to the study of the brittle fracture behavior of these aluminides; as a result, both intrinsic and extrinsic factors governing brittle fracture have been identified. Surprisingly, moisture-induced hydrogen embrittlement has been recognized as one of the major causes of low ductility and brittle fracture in Ni{sub 3}Al, Fe{sub 3}Al and FeAl at ambient temperatures. These efforts have led to the development of ductile and strong aluminide alloys for structural applications. Industrial interest in these aluminide alloys is high, and several examples of industrial involvement are mentioned.

  13. Structure and Properties of the Aluminide Coatings on the Inconel 625 Superalloy

    Science.gov (United States)

    Adamiak, Stanisław; Bochnowski, Wojciech; Dziedzic, Andrzej; Filip, Ryszard; Szeregij, Eugeniusz

    2016-01-01

    The research samples used in this study were based on the Inconel 625 alloy; the examined samples were coated with aluminide films deposited in a low-activity chemical vapor deposition (CVD) process. The samples' microstructure was investigated with optical and electron microscopy and energy dispersive X-ray spectroscopy analysis. Hardness measurements were performed using Vickers and Berkovich test methods. The adhesion of the aluminide coating was determined by fractography. It was shown that the fracture mechanism was different for the respective zones of the aluminide coating and the substrate material. The outer zone of the aluminide coating is characterized by an intercrystalline fracture, with a small contribution of transcrystalline fracture within individual grains (large crystallites in the bottom of the zone, composed of smaller crystallites, also show an intercrystalline fracture). The substrate material exhibited a ductile intercrystalline fracture. Based on this investigation, an increase of the microhardness of the material occurring at loads below 0.2 N was observed. When determining microhardness of aluminide coating it is necessary to take into account the optimal choice of the indentation tip.

  14. Microstructure and phase morphology during thermochemical processing of {alpha}{sub 2}-based titanium aluminide castings

    Energy Technology Data Exchange (ETDEWEB)

    Saqib, M. [Wright State Univ., Dayton, OH (United States). Dept. of Mechanical and Materials Engineering; Apgar, L.S. [Dayton Univ., OH (United States). Graduate Materials Engineering; Eylon, D. [Dayton Univ., OH (United States). Graduate Materials Engineering; Weiss, I. [Wright State Univ., Dayton, OH (United States). Dept. of Mechanical and Materials Engineering

    1995-12-31

    Changes in the microstructure, volume fraction and distribution of phases during different stages of thermochemical processing of Ti-25Al-10Nb-3V-1Mo (at.%) castings were investigated. Up to 14.5 at.% (0.35 wt.%) of hydrogen was introduced into the material by gas charging at temperatures between 650 and 980 C for times up to 20 h. The material was subsequently dehydrogenated by vacuum annealing at 650 C for 48 h. Investment cast Ti-25Al-10Nb-3V-1Mo alloy, hot isostatically pressed (HIP) at 1175 C at 260 MPa for 6 h, was used as the starting material. The microstructure of the as-HIP material consists of {alpha}{sub 2}, B2 and orthorhombic phases. The {alpha}{sub 2} phase exists in equiaxed, Widmanstaeten and cellular morphologies. The B2 phase is observed mainly along {alpha}{sub 2}/{alpha}{sub 2} boundaries. Some {alpha}{sub 2} Widmanstaeten also contain very fine orthorhombic phase in a plate-like morphology. Hydrogenation of the material modified the microstructure; however, the morphology of the {alpha}{sub 2} and B2 phases did not change. Furthermore, hydride precipitation and a higher volume fraction of the orthorhombic phase were observed compared with the as-HIP material. Following dehydrogenation, the hydrogen level in the material was found to be less than 0.1 at.% (0.0025wt.%). Transmission electron microscopy of the dehydrogenated material did not reveal the presence of hydride precipitates; however, the high volume fraction of the orthorhombic phase was found to persist following dehydrogenation. (orig.)

  15. R&D on Composition and Processing of Titanium Aluminide Alloys for Turbine Engines

    Science.gov (United States)

    1982-07-01

    and is approved for publication. 4.2 / /;ARRY LIPS NORMA M. GEYER Projec Engineer Technical Area Manager Processing & High Temperature Materials...of as- forged Ti- 25A1-10Nb- 3V- iMo 24 alloy pancake forging. This was forged on iso - thermal dies at 1120C (20SOF) in one step from a cast ingot. 14

  16. Halo Formation During Solidification of Refractory Metal Aluminide Ternary Systems

    Science.gov (United States)

    D'Souza, N.; Feitosa, L. M.; West, G. D.; Dong, H. B.

    2018-02-01

    The evolution of eutectic morphologies following primary solidification has been studied in the refractory metal aluminide (Ta-Al-Fe, Nb-Al-Co, and Nb-Al-Fe) ternary systems. The undercooling accompanying solid growth, as related to the extended solute solubility in the primary and secondary phases can be used to account for the evolution of phase morphologies during ternary eutectic solidification. For small undercooling, the conditions of interfacial equilibrium remain valid, while in the case of significant undercooling when nucleation constraints occur, there is a departure from equilibrium leading to unexpected phases. In Ta-Al-Fe, an extended solubility of Fe in σ was observed, which was consistent with the formation of a halo of μ phase on primary σ. In Nb-Al-Co, a halo of C14 is formed on primary CoAl, but very limited vice versa. However, in the absence of a solidus projection it was not possible to definitively determine the extended solute solubility in the primary phase. In Nb-Al-Fe when nucleation constraints arise, the inability to initiate coupled growth of NbAl3 + C14 leads to the occurrence of a two-phase halo of C14 + Nb2Al, indicating a large undercooling and departure from equilibrium.

  17. Plasticity Effects in Dynamically Loaded Nickel Aluminide Bicrystals

    Energy Technology Data Exchange (ETDEWEB)

    Loomis, E; Swift, D; McNaney, J; Lorenzana, H; Peralta, P

    2008-12-02

    Elastic and plastic anisotropy are believed to play large roles in the dynamic deformation of many materials at the grain-level. More importantly to polycrystalline materials is how velocity and stress perturbations are transmitted across interfaces in anisotropic materials. Very little work has been done in this area even though it is important for understanding shock/grain boundary interactions. Therefore, experiments have been performed using nanosecond laser shocks of grown Nickel Aluminide bicrystals at tens of GPa. Velocity histories were measured along a line on the back (free) surface of the bicrystals and used to characterize the material behavior. Unstable plastic flow in <100> grains was seen to occur when loaded above 700 m/s free surface velocity. Flow stresses in <111> and <100> grains were measured to be 2.9 and 3.3 GPa, respectively. Calculations were performed based on anisotropic elasticity and dislocation motion on primary slip systems to measure plastic flow properties where plastic strain-rates on the order of 10{sup 6} s{sup -1} were calculated using the experimental velocity histories. Definitive evidence of plastic wave scattering at the grain boundary was not observed experimentally; however, behavior across the grain boundary has been measured. The observations show that a smooth transition occurs between the elastic precursors in both grains as well as the plastic waves (when plastic flow is evident). An anisotropic elastic-plastic wave scattering model has been developed to explain the mechanisms affecting shock/grain boundary interactions.

  18. Analysis of weld solidification cracking in cast nickel aluminide alloys

    International Nuclear Information System (INIS)

    Santella, M.L.; Feng, Z.

    1995-01-01

    A study of the response of several nickel aluminide alloys to SigmaJig testing was done to examine their weld solidification cracking behavior and the effect of Zr concentration. The alloys were based on the Ni-8Al-7.7Cr-1.5Mo-0.003B wt% composition and contained Zr concentrations of 3, 4.5, and 6 wt%. Vacuum induction melted ingots with a diameter of 2.7 in and weight about 18 lb were made of each alloy, and were used to make 2 x 2 x 0.030 in specimens for the Sigmajig test. The gas tungsten arc welds were made at travel speeds of 10, 20, and 30 ipm with heat inputs of 2--2.5 kJ/in. When an arc was established before traveling onto the test specimen centerline cracking was always observed. This problem was overcome by initiating the arc directly on the specimens. Using this approach, the 3 wt% Zr alloy withstood an applied stress of 24 ksi without cracking at a welding speed of 10 ipm. This alloy cracked at 4 ksi applied at 20 ipm, and with no applied load at 30 ipm. Only limited testing was done on the remaining alloys, but the results indicate that resistance to solidification cracking increases with Zr concentration. Zirconium has limited solid solubility and segregates strongly to interdendritic regions during solidification where it forms a Ni solid solution-Ni 5 Zr eutectic. The volume fraction of the eutectic increases with Zr concentration. The solidification cracking behavior of these alloys is consistent with phenomenological theory, and is discussed in this context. The results from SigmaJig testing are analyzed using finite element modeling of the development of mechanical strains during solidification of welds. Experimental data from the test substantially agree with recent analysis results

  19. Rhodium and Hafnium Influence on the Microstructure, Phase Composition, and Oxidation Resistance of Aluminide Coatings

    Directory of Open Access Journals (Sweden)

    Maryana Zagula-Yavorska

    2017-12-01

    Full Text Available A 0.5 μm thick layer of rhodium was deposited on the CMSX 4 superalloy by the electroplating method. The rhodium-coated superalloy was hafnized and aluminized or only aluminized using the Chemical vapour deposition method. A comparison was made of the microstructure, phase composition, and oxidation resistance of three aluminide coatings: nonmodified (a, rhodium-modified (b, and rhodium- and hafnium-modified (c. All three coatings consisted of two layers: the additive layer and the interdiffusion layer. Rhodium-doped (rhodium- and hafnium-doped β-NiAl phase was found in the additive layer of the rhodium-modified (rhodium- and hafnium-modified aluminide coating. Topologically Closed-Pack (μ and σ phases precipitated in the matrix of the interdiffusion layer. Rhodium also dissolved in the β-NiAl phase between the additive and interdiffusion layers, whereas Hf-rich particles precipitated in the (Ni,RhAl phase at the additive/interdiffusion layer interface in the rhodium- and hafnium-modified coating (c. The rhodium-modified aluminide coating (b has better oxidation resistance than the nonmodified one (a, whereas the rhodium- and hafnium-modified aluminide coating (c has better oxidation resistance than the rhodium-modified (b and nonmodified (a ones.

  20. Optimization of laboratory hot rolling of brittle Fe-40at.%Al-Zr-B aluminide

    Czech Academy of Sciences Publication Activity Database

    Schindler, I.; Hadasik, E.; Kopeček, Jaromír; Kawulok, P.; Fabík, R.; Opěla, P.; Rusz, S.; Kawulok, R.; Jabłońska, M.

    2015-01-01

    Roč. 60, č. 3 (2015), s. 1693-1701 ISSN 1733-3490 R&D Projects: GA ČR(CZ) GAP107/10/0438 Institutional support: RVO:68378271 Keywords : iron aluminides * EBSD * textures * modelling Subject RIV: JG - Metallurgy Impact factor: 1.090, year: 2014

  1. Development and Processing of Nickel Aluminide-Carbide Alloys

    Science.gov (United States)

    Newport, Timothy Scott

    1996-01-01

    With the upper temperature limit of the Ni-based superalloys attained, a new class of materials is required. Intermetallics appear as likely candidates because of their attractive physical properties. With a relatively low density, high thermal conductivity, excellent oxidation resistance, high melting point, and simple crystal structure, nickel aluminide (NiAl) appears to be a potential candidate. However, NiAl is limited in structural applications due to its low room temperature fracture toughness and poor elevated temperature strength. One approach to improving these properties has been through the application of eutectic composites. Researchers have shown that containerless directional solidification of NiAl-based eutectic alloys can provide improvement in both the creep strength and fracture toughness. Although these systems have shown improvements in the mechanical properties, the presence of refractory metals increases the density significantly in some alloys. Lower density systems, such as the carbides, nitrides, and borides, may provide NiAl-based eutectic structure. With little or no information available on these systems, experimental investigation is required. The objective of this research was to locate and develop NiAl-carbide eutectic alloys. Exploratory arc-melts were performed in NiAl-refractory metal-C systems. Refractory metal systems investigated included Co, Cr, Fe, Hf, Mo, Nb, Ta, Ti, W, and Zr. Systems containing carbides with excellent stability (i.e.,HfC, NbC, TaC, TiC, and ZrC) produced large blocky cubic carbides in an NiAl matrix. The carbides appeared to have formed in the liquid state and were randomly distributed throughout the polycrystalline NiAl. The Co, Cr, Fe, Mo, and W systems contained NiAl dendrites with a two-phase interdendritic microconstituent present. Of these systems, the NiAl-Mo-C system had the most promising microstructure for in-situ composites. Three processing techniques were used to evaluate the NiAl-Mo-C system

  2. Titanium Honeycomb Panel Testing

    Science.gov (United States)

    Richards, W. Lance; Thompson, Randolph C.

    1996-01-01

    Thermal-mechanical tests were performed on a titanium honeycomb sandwich panel to experimentally validate the hypersonic wing panel concept and compare test data with analysis. Details of the test article, test fixture development, instrumentation, and test results are presented. After extensive testing to 900 deg. F, non-destructive evaluation of the panel has not detected any significant structural degradation caused by the applied thermal-mechanical loads.

  3. Electrowinning molten titanium from titanium dioxide

    CSIR Research Space (South Africa)

    Van Vuuren, DS

    2005-10-01

    Full Text Available The value chain of titanium products shows that the difference between the cost of titanium ingot and titanium dioxide is about $9/kg titanium. In contrast, the price of aluminium, which is produced in a similar way, is only about $1.7/kg...

  4. Chemical vapor deposition of aluminide coatings on iron, nickel and superalloys

    International Nuclear Information System (INIS)

    John, John T.; De, P.K.; Dubey, Vivekanand; Srinivasa, Raman

    2009-08-01

    Aluminide coatings are a class of intermetallic coatings applied on nickel and cobalt base superalloys and steels to protect them from different forms of environmental degradation at high temperatures. In this report a CVD system that can produce the aluminide coatings on iron, nickel and nickel base alloys has been described and the result of chemical vapor deposition of aluminide coatings on iron specimens, their characterization, and property evaluation have been presented. The CVD system consists of an AlCl 3 bath, a stainless steel retort as a hot-wall reacto, cold traps and vacuum system. Aluminium chloride vapor was carried in a stream of hydrogen gas at a flow rate of 150 SCCM (standard cubic centimeter per minute) into the CVD reactor maintained in the temperature range of 1173 - 1373 K and at a pressure of 1.33 kPa (10 Torr). Aluminum deposition takes place from aluminium subchlorides produced by reaction between AlCl 3 and pure aluminum kept in the CVD reactor. The aluminum diffuses into the iron samples and iron aluminide phases are formed at the surface. The coatings were shining bright and showed good adherence to the substrate. The coatings consisted of FeAl phase over a wide range of experimental conditions. The growth kinetics of the coating followed a parabolic rate law and the mean activation energy was 212 ±16 kJ/mol. Optical microscopic studies on the transverse section of the coating showed that the aluminide coating on iron consisted of two layers. The top layer had a thickness in the range of 20-50 μm, and the under layer had thickness ranging from 35 to 250 μm depending on coating temperature in two hours. The thickness of the aluminide layer increased with coating duration and temperature. Electron microprobe studies (EPMA) showed that the aluminum concentration decreased steadily as distance from the surface increased. TEM studies showed that the outer most layer had a B2 order (of the FeAl phase), which extended even into the under

  5. Corrosion resistant iron aluminides exhibiting improved mechanical properties and corrosion resistance

    Science.gov (United States)

    Liu, Chain T.; McKamey, Claudette G.; Tortorelli, Peter F.; David, Stan A.

    1994-01-01

    The specification discloses a corrosion-resistant intermetallic alloy comprising, in atomic percent, an FeAl iron aluminide containing from about 30 to about 40% aluminum alloyed with from about 0.01 to 0.4% zirconium and from 0.01 to about 0.8% boron. The alloy exhibits considerably improved room temperature ductility for enhanced usefulness in structural applications. The high temperature strength and fabricability is improved by alloying with molybdenum, carbon, chromium and vanadium.

  6. Effect of cerium addition on the corrosion behaviour of carbon-alloyed iron aluminides

    International Nuclear Information System (INIS)

    Sriram, S.; Balasubramaniam, R.; Mungole, M.N.; Bharagava, S.; Baligidad, R.G.

    2006-01-01

    The effect of Ce addition on the microstructure and corrosion behavior of carbon-alloyed iron aluminides Fe-20.0Al-2.0C, Fe-18.5Al-3.6C and Fe-19.2Al-3.3C-0.07Ce (in at.%) has been studied. The potentiodynamic polarization behaviour of the alloys was evaluated in freely aerated 0.25 mol/l H 2 SO 4 . A 0.05% C steel was used for comparison purposes. All the alloys exhibited active-passive behaviour in the acidic solution. The addition of Ce destroyed passivity as indicated by lower breakdown potentials in polarization studies. This has been related to the finer distribution of the carbides in the microstructure. Corrosion rates were evaluated by immersion testing. The iron aluminide with Ce addition exhibited a lower corrosion rate compared to the aluminides without Ce addition. This has been attributed to modifications in surface film with Ce addition. Scanning electron microscopy of corroded surfaces indicated that the carbon-alloyed intermetallics were susceptible to localized galvanic corrosion due to the presence of carbides in the microstructure

  7. Fabrication and mechanical properties of Fe sub 3 Al-based iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K.; McKamey, C.G.; Howell, C.R.; Baldwin, R.H.

    1990-03-01

    Iron aluminides based on Fe{sub 3}Al are ordered intermetallic alloys that offer good oxidation resistance, excellent sulfidation resistance, and lower material cost than many stainless steels. These materials also conserve strategic elements such as chromium and have a lower density than stainless steels. However, limited ductility at ambient temperature and a sharp drop in strength have been major deterrents to their acceptance for structural applications. This report presents results on iron aluminides with room-temperature elongations of 15 to 20%. Ductility values were improved by a combination of thermomechanical processing and heat-treatment control. This method of ductility improvement has been demonstrated for a range of compositions. Melting, casting, and processing of 7-kg (15-lb) heats produced at the Oak Ridge National Laboratory (ORNL) and 70-kg (150-lb) commercial heats are described. Vacuum melting and other refining processes such as electroslag remelting are recommended for commercial heats. The Fe{sub 3}Al-based iron aluminides are hot workable by forging or extruding at temperatures in the range of 850 to 1100{degree}C. rolling at 800{degree}C is recommended with a final 50% reduction at 650{degree}C. Tensile and creep properties of 7- and 70-kg (15- and 150-lb) heats are presented. The presence of impurities such as manganese an silicon played an important role in reducing the ductility of commercially melted heats. 7 refs., 60 figs., 12 tabs.

  8. Creating nanoshell on the surface of titanium hydride bead

    Directory of Open Access Journals (Sweden)

    PAVLENKO Vyacheslav Ivanovich

    2016-12-01

    Full Text Available The article presents data on the modification of titanium hydride bead by creating titanium nanoshell on its surface by ion-plasma vacuum magnetron sputtering. To apply titanium nanoshell on the titanium hydride bead vacuum coating plant of multifunctional nanocomposite coatings QVADRA 500 located in the center of high technology was used. Analysis of the micrographs of the original surface of titanium hydride bead showed that the microstructure of the surface is flat, smooth, in addition the analysis of the microstructure of material surface showed the presence of small porosity, roughness, mainly cavities, as well as shallow longitudinal cracks. The presence of oxide film in titanium hydride prevents the free release of hydrogen and fills some micro-cracks on the surface. Differential thermal analysis of both samples was conducted to determine the thermal stability of the initial titanium hydride bead and bead with applied titanium nanoshell. Hydrogen thermal desorption spectra of the samples of the initial titanium hydride bead and bead with applied titanium nanoshell show different thermal stability of compared materials in the temperature range from 550 to 860о C. Titanium nanoshells applied in this way allows increasing the heat resistance of titanium hydride bead – the temperature of starting decomposition is 695о C and temperature when decomposition finishes is more than 1000о C. Modified in this way titanium hydride bead can be used as a filler in the radiation protective materials used in the construction or upgrading biological protection of nuclear power plants.

  9. Titanium nanostructures for biomedical applications

    International Nuclear Information System (INIS)

    Kulkarni, M; Gongadze, E; Perutkova, Š; A Iglič; Mazare, A; Schmuki, P; Kralj-Iglič, V; Milošev, I; Mozetič, M

    2015-01-01

    Titanium and titanium alloys exhibit a unique combination of strength and biocompatibility, which enables their use in medical applications and accounts for their extensive use as implant materials in the last 50 years. Currently, a large amount of research is being carried out in order to determine the optimal surface topography for use in bioapplications, and thus the emphasis is on nanotechnology for biomedical applications. It was recently shown that titanium implants with rough surface topography and free energy increase osteoblast adhesion, maturation and subsequent bone formation. Furthermore, the adhesion of different cell lines to the surface of titanium implants is influenced by the surface characteristics of titanium; namely topography, charge distribution and chemistry. The present review article focuses on the specific nanotopography of titanium, i.e. titanium dioxide (TiO 2 ) nanotubes, using a simple electrochemical anodisation method of the metallic substrate and other processes such as the hydrothermal or sol-gel template. One key advantage of using TiO 2 nanotubes in cell interactions is based on the fact that TiO 2 nanotube morphology is correlated with cell adhesion, spreading, growth and differentiation of mesenchymal stem cells, which were shown to be maximally induced on smaller diameter nanotubes (15 nm), but hindered on larger diameter (100 nm) tubes, leading to cell death and apoptosis. Research has supported the significance of nanotopography (TiO 2 nanotube diameter) in cell adhesion and cell growth, and suggests that the mechanics of focal adhesion formation are similar among different cell types. As such, the present review will focus on perhaps the most spectacular and surprising one-dimensional structures and their unique biomedical applications for increased osseointegration, protein interaction and antibacterial properties. (topical review)

  10. Titanium nanostructures for biomedical applications

    Science.gov (United States)

    Kulkarni, M.; Mazare, A.; Gongadze, E.; Perutkova, Š.; Kralj-Iglič, V.; Milošev, I.; Schmuki, P.; Iglič, A.; Mozetič, M.

    2015-02-01

    Titanium and titanium alloys exhibit a unique combination of strength and biocompatibility, which enables their use in medical applications and accounts for their extensive use as implant materials in the last 50 years. Currently, a large amount of research is being carried out in order to determine the optimal surface topography for use in bioapplications, and thus the emphasis is on nanotechnology for biomedical applications. It was recently shown that titanium implants with rough surface topography and free energy increase osteoblast adhesion, maturation and subsequent bone formation. Furthermore, the adhesion of different cell lines to the surface of titanium implants is influenced by the surface characteristics of titanium; namely topography, charge distribution and chemistry. The present review article focuses on the specific nanotopography of titanium, i.e. titanium dioxide (TiO2) nanotubes, using a simple electrochemical anodisation method of the metallic substrate and other processes such as the hydrothermal or sol-gel template. One key advantage of using TiO2 nanotubes in cell interactions is based on the fact that TiO2 nanotube morphology is correlated with cell adhesion, spreading, growth and differentiation of mesenchymal stem cells, which were shown to be maximally induced on smaller diameter nanotubes (15 nm), but hindered on larger diameter (100 nm) tubes, leading to cell death and apoptosis. Research has supported the significance of nanotopography (TiO2 nanotube diameter) in cell adhesion and cell growth, and suggests that the mechanics of focal adhesion formation are similar among different cell types. As such, the present review will focus on perhaps the most spectacular and surprising one-dimensional structures and their unique biomedical applications for increased osseointegration, protein interaction and antibacterial properties.

  11. Saturated bonds and anomalous electronic transport in transition-metal aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, T.

    2006-05-22

    This thesis deals with the special electronic properties of the transition-metal aluminides. Following quasicrystals and their approximants it is shown that even materials with small elementary cells exhibit the same surprising effects. So among the transition-metal aluminides also semi-metallic and semiconducting compounds exist, although if they consist of classic-metallic components like Fe, Al, or Cr. These properties are furthermore coupled with a deep pseusogap respectively gap in the density of states and strongly covalent bonds. Bonds are described in this thesis by two eseential properties. First by the bond charge and second by the energetic effect of the bond. It results that in the caes of semiconducting transition-metal aluminides both a saturation of certain bonds and a bond-antibond alteration in the Fermi level is present. By the analysis of the near-order in form of the so-calles coordination polyeders it has been succeeded to establish a simple rule for semiconductors, the five-fold coordination for Al. This rule states that aluminium atoms with their three valence electrons are not able to build more than five saturated bonds to their nearest transition-metal neighbours. In excellent agreement with the bond angles predicted theoretically under assumption of equal-type bonds it results that all binary transition-element aluminide semiconductors exhibit for the Al atoms the same near order. Typical values for specific resistances of the studied materials at room temperature lie in the range of some 100 {mu}{omega}cm, which is farly larger than some 10 {mu}{omega}cm as in the case of the unalloyed metals. SUrprising is furthermore a high transport anisotropy with a ratio of the specific resistances up to 3.0. An essential result of this thesis can be seen in the coupling of the properties of the electronic transport and the bond properties. The small conducitivities could be explained by small values in the density of states and a bond

  12. Struktura i svojstva plazma sprej Aps - Nikal - Aluminid prevlake

    Directory of Open Access Journals (Sweden)

    Mihailo Rade Mrdak

    2013-06-01

    Full Text Available Cilj ovog istraživanja je da se optimizacijom parametara deponovanja dobiju optimalne strukturne i mehaničke karakteristike Ni20Al slojeva, koji će se primeniti na delu za radarsku stanicu. Prah je deponovan atmosferskim plazma sprej (APS postupkom sa plazma sprej (PS odstojanjem 80, 90 i 100 mm. Prevlaka sa najboljim karakteristikama deponovana je na utvrđivaču  turbo- gasnog motora GTD 2PV8 za radarsku stanicu, da bi se smanjio uticaj oksidacije  i vibracija na habanje na 450–500°C. Procene Ni20Al slojeva prevlake urađene su na osnovu njihovih mikrostruktura, mikrotvrdoća i zatezne čvrstoće. Najbolju strukturu i mehaničke  karakteristike pokazali su slojevi deponovani sa plazma sprej odstojanjem od 80 mm. Morfologija površine deponovane prevlake i morfologija loma najboljih slojeva ispitana je na SEM-u (skening elektronskom mikroskopu. Mikrostruktura slojeva deponovanih prevlaka ispitana je na svetlosnom mikroskopu. Mikrostrukturna analiza deponovanih slojevima urađena je u skladu sa standardom Pratt-Whitney. Procena mehaničkih karakteristika slojeva urađena je ispitivanjem mikrotvrdoće metodom HV0.3 i čvrstoće spoja ispitivanjem na zatezanje. Istraživanja su pokazala da plazma sprej odstojanje bitno utiče na mehaničke osobine i mikrostrukture prevlaka. Efekat primene Ni20Al prevlake ispitan je na utvrđivaču  turbogasnog motora GTD 2PV8 na radarskoj stanici.   Uvod   Kompozitni nikal-aluminid prah Ni20Al razvijen je za potrebe vazduhoplovne industrije. Važna karakteristika je dobro deponovanje praha plazma sprejom na atmosferskom pritisku (APS. Ovaj materijal ima dobru otpornost na oksidaciju,  koroziju i eroziju. Materijal se može proizvoditi kao legura ili kao  kompozitni prah. Najvažnija karakteristika nikal-aluminida je velika čvrstoća i žilavost  sa odličnom otpornošću na visoke temperature. NiAl prevlake deponovane plazma sprejom našle su široku primenu za zaštitu delova koji su izlo

  13. Oxidation-sulfidation behavior of Ni aluminide in oxygen-sulfur mixed-gas atmospheres

    International Nuclear Information System (INIS)

    Natesan, K.

    1988-01-01

    Oxidation-sulfidation studies were conducted with sheet samples of nickel aluminide, containing 23.5 at. % Al, 0.5 at. % Hf, and 0.2 at. % B, in an annealed condition and after preoxidation treatments. Continuous weight-change measurements were made by a thermogravimetric technique in exposure atmospheres of air, a low-pO/sub 2/ gas mixture, and low-pO/sub 2/ gas mixtures with several levels of sulfur. The air-exposed specimens developed predominantly nickel oxide; the specimen exposed to a low-pO/sub 2/ environment developed an aluminum oxide scale. As the sulfur content of the gas mixture increased, the alumina scale exhibited spallation and the alloy tended to form nickel sulfide as the reaction phase. The results indicated that the sulfidation reaction of nickel aluminide specimens (both bare and preoxidized) was determined by the rate of transport of nickel from the substrate through the scale to the gas/alumina scale interface, the mechanical integrity of the oxide scale, and the H/sub 2/S concentration in the exposure environment

  14. Formation of alumina-aluminide coatings on ferritic-martensitic T91 steel

    Directory of Open Access Journals (Sweden)

    Choudhary R.K.

    2014-01-01

    Full Text Available In this work, alumina-aluminide coatings were formed on ferritic-martensitic T91 steel substrate. First, coatings of aluminum were deposited electrochemically on T91 steel in a room temperature AlCl3-1-ethyl-3-methyl imidazolium chloride ionic liquid, then the obtained coating was subjected to a two stage heat treatment procedure consisting of prolonged heat treatment of the sample in vacuum at 300 ○C followed by oxidative heat treatment in air at 650 ○C for 16 hours. X-ray diffraction measurement of the oxidatively heat treated samples indicated formation of Fe-Al and Cr-Al intermetallics and presence of amorphous alumina. Energy dispersive X-ray spectroscopy measurement confirmed 50 wt- % O in the oxidized coating. Microscratch adhesion test conducted on alumina-aluminide coating formed on T91 steel substrate showed no major adhesive detachment up to 20 N loads. However, adhesive failure was observed at a few discrete points on the coating along the scratch track.

  15. Single-step gas phase synthesis of stable iron aluminide nanoparticles with soft magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Vernieres, Jerome, E-mail: Jerome.vernieres@oist.jp; Benelmekki, Maria; Kim, Jeong-Hwan; Grammatikopoulos, Panagiotis; Diaz, Rosa E. [Nanoparticles by Design Unit, Okinawa Institute of Science and Technology (OIST) Graduate University, 1919-1 Tancha, Onna Son, Okinawa 904-0495 (Japan); Bobo, Jean-François [Centre d’Elaboration de Materiaux et d’Etudes Structurales (CEMES), 29 rue Jeanne Marvig, 31055 Toulouse Cedex 4 (France); Sowwan, Mukhles, E-mail: Mukhles@oist.jp [Nanoparticles by Design Unit, Okinawa Institute of Science and Technology (OIST) Graduate University, 1919-1 Tancha, Onna Son, Okinawa 904-0495 (Japan); Nanotechnology Research Laboratory, Al-Quds University, P.O. Box 51000, East Jerusalem, Palestine (Country Unknown)

    2014-11-01

    Soft magnetic alloys at the nanoscale level have long generated a vivid interest as candidate materials for technological and biomedical purposes. Consequently, controlling the structure of bimetallic nanoparticles in order to optimize their magnetic properties, such as high magnetization and low coercivity, can significantly boost their potential for related applications. However, traditional synthesis methods stumble upon the long standing challenge of developing true nanoalloys with effective control over morphology and stability against oxidation. Herein, we report on a single-step approach to the gas phase synthesis of soft magnetic bimetallic iron aluminide nanoparticles, using a versatile co-sputter inert gas condensation technique. This method allowed for precise morphological control of the particles; they consisted of an alloy iron aluminide crystalline core (DO{sub 3} phase) and an alumina shell, which reduced inter-particle interactions and also prevented further oxidation and segregation of the bimetallic core. Remarkably, the as-deposited alloy nanoparticles show interesting soft magnetic properties, in that they combine a high saturation magnetization (170 emu/g) and low coercivity (less than 20 Oe) at room temperature. Additional functionality is tenable by modifying the surface of the particles with a polymer, to ensure their good colloidal dispersion in aqueous environments.

  16. Effect of Hf Additions to Pt Aluminide Bond Coats on EB-PVD TBC Life

    Science.gov (United States)

    Nesbitt, James; Nagaraj, Ben; Williams, Jeffrey

    2000-01-01

    Small Hf additions were incorporated into a Pt aluminide coating during chemical vapor deposition (CVD) on single crystal RENE N5 substrates. Standard yttria-stabilized zirconia top coats were subsequently deposited onto the coated substrates by electron beam-physical vapor deposition (EB-PVD). The coated substrates underwent accelerated thermal cycle testing in a furnace at a temperature in excess of 1121 C (2050 F) (45 minute hot exposure, 15 minute cool to approximately 121 C (250 F)) until the thermal barrier coating (TBC) failed by spallation. Incorporating Hf in the bond coat increased the TBC life by slightly more than three times that of a baseline coating without added Hf. Scanning electron microscopy of the spalled surfaces indicated that the presence of the Hf increased the adherence of the thermally grown alumina to the Pt aluminide bond coat. The presence of oxide pegs growing into the coating from the thermally grown alumina may also partially account for the improved TBC life by creating a near-surface layer with a graded coefficient of thermal expansion.

  17. Microstructural Study on Oxidation Resistance of Nonmodified and Platinum Modified Aluminide Coating

    Science.gov (United States)

    Zagula-Yavorska, Maryana; Sieniawski, Jan

    2014-03-01

    Platinum electroplating layers (3 and 7 μm thick) were deposited on the surface of the Inconel 713 LC, CMSX 4, and Inconel 625 Ni-base superalloys. Diffusion treatment at 1050°C for 2 h under argon atmosphere was performed after electroplating. Diffusion treated samples were aluminized according to the low activity CVD process at 1050°C for 8 h. The nonmodified aluminide coatings consist of NiAl phase. Platinum modification let to obtain the (Ni,Pt)Al phase in coatings. The coated samples were subjected to cyclic oxidation testing at 1100°C. It was discovered that increase of the platinum electroplating thickness from 3 to 7 μm provides the improvement of oxidation resistance of aluminide coatings. Increase of the platinum thickness causes decreases in weight change and decreases in parabolic constant during oxidation. The platinum provides the pure Al2O3 oxide formation, slow growth oxide layer, and delay the oxide spalling during heating-cooling thermal cycles.

  18. Gentamicin-Eluting Titanium Dioxide Nanotubes Grown on the Ultrafine-Grained Titanium.

    Science.gov (United States)

    Nemati, Sima Hashemi; Hadjizadeh, Afra

    2017-08-01

    Titanium (Ti)-based materials is the most appropriate choices for the applications as orthopedic and dental implants. In this regard, ultrafine-grained (UFG) titanium with an enhanced mechanical properties and surface energy has attracted more attention. Titanium dioxide (TiO 2 ) nanotubes grown on the titanium could enhance bone bonding, cellular response and are good reservoirs for loading drugs and antibacterial agents. This article investigates gentamicin loading into and release from the TiO 2 nanotubes, grown on the UFG compared to coarse-grained (CG) titanium substrate surfaces. Equal Channel Angular Pressing (ECAP) was employed to produce the UFG structure titanium. TiO 2 nanotubes were grown by the anodizing technique on both UFG and CG titanium substrate surfaces. Scanning electron microscopy (SEM) imaging confirmed TiO 2 nanotube growth on the surface. The UV-vis spectroscopy analysis results show that the amount of gentamicin load-release in the anodized UFG titanium sample is higher than that of CG one which can be explained in terms of thicker TiO 2 nanotube arrays layer formed on UFG sample. Moreover, the anodized UFG titanium samples released the drug in a longer time than CG (1 day for the UFG titanium vs. 3 h for the CG one). Regarding wettability analysis, anodized UFG titanium sample showed more enhanced hydrophilicity than CG counterpart. Therefore, the significantly smaller grain size of pure titanium provided by the ECAP technique coupled with appropriate subsequent anodization treatment not only offers a good combination of biocompatibility and adequate mechanical properties but also it provides a delayed release condition for gentamicin.

  19. The effects of HIP processing on microstructure and phase relations in. alpha. sub 2 -base titanium aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Saqib, M. (Dept. of Mechanical and Materials Engineering, Wright State Univ., Dayton, OH (United States)); Apgar, L.S.; Eylon, D. (Graduate Materials Engineering, Univ. of Dayton, OH (United States)); Weiss, I. (Dept. of Mechanical and Materials Engineering, Wright State Univ., Dayton, OH (United States))

    1992-05-30

    Cast {alpha}{sub 2}-base alloy (Ti-25Al-10Nb-3V-1Mo, at.%) underwent hot isostatic pressing (HIP) at temperatures ranging from 925 to 1125degC and pressures of 100-270 MPa. Effects of temperature and pressure during HIP, on microstructure and volume fraction of the phases present, were investigated. Microstructural characterization was carried out using optical microscopy and transmission electron microscopy. The phases present were identified using selected area and convergent beam electron diffraction. Volume fraction of the phases was determined using X-ray diffraction. Optimum refinement in the microstructure was obtained following HIP at 1020degC/262 MPa/6 h. The volume fraction of the B2 phase increased from 12% in the as-cast condition to 45% following HIP at 982degC/262 MPa/6 h. Experiments on forged Ti-25Al-10Nb-3V-1Mo alloy demonstrated that changes in volume fraction of the phases owing to HIP was applicable for cast as well as forged material. Sharp decrease in the volume fraction of the B2 phase was observed when as-HIP materials were aged at elevated temperature. Possible mechanisms of these changes in the phase stability and microstructure are discussed. (orig.).

  20. Titanium hermetic seals

    Science.gov (United States)

    Brow, Richard K.; Watkins, Randall D.

    1995-01-01

    Titanium is prenitrided by being heated in a nitrogen environment under conditions which give rise to the formation of a titanium-nitride surface layer on the titanium. Titanium thus prenitrided may be used in electrical components which are hermetically sealed using silicate glasses and standard glass sealing techniques. According to the method of the invention, alkali volatilization and formation of deleterious interfacial silicide are inhibited.

  1. Titanium and titanium alloys: fundamentals and applications

    National Research Council Canada - National Science Library

    Leyens, C; Peters, M

    2003-01-01

    ... number of titanium alloys have paved the way for light metals to vastly expand into many industrial applications. Titanium and its alloys stand out primarily due to their high specific strength and excellent corrosion resistance, at just half the weight of steels and Ni-based superalloys. This explains their early success in the aerospace and the...

  2. High-temperature corrosion-resistant iron-aluminide (FeAl) alloys exhibiting improved weldability

    Science.gov (United States)

    Maziasz, Philip J.; Goodwin, Gene M.; Liu, Chain T.

    1996-01-01

    This invention relates to improved corrosion-resistant iron-aluminide intermetallic alloys. The alloys of this invention comprise, in atomic percent, from about 30% to about 40% aluminum alloyed with from about 0.1% to about 0.5% carbon, no more than about 0.04% boron such that the atomic weight ratio of boron to carbon in the alloy is in the range of from about 0.01:1 to about 0.08:1, from about 0.01 to about 3.5% of one or more transition metals selected from Group IVB, VB, and VIB elements and the balance iron wherein the alloy exhibits improved resistance to hot cracking during welding.

  3. Oxidation behavior of Hf-modified platinum aluminide coatings during thermal cycling

    Directory of Open Access Journals (Sweden)

    Liya Ye

    2018-02-01

    Full Text Available Platinum aluminide coatings with different Hf contents were fabricated by using HfCl4. The oxidation kinetics and the rumpling behavior of oxide scale were investigated. After thermal cycling, the coating with 0.46 wt% Hf showed least weight gain. With the increase of Hf content, rumpling extent of the scale decreased. Meanwhile, HfO2 preferentially formed in the scale resulting in the increase of scale thickness. The oxidation of excessive Hf even caused the spallation of the scale. The results in the present study indicate that although Hf plays an important role in decreasing rumpling extent of TGO, the oxidation of Hf decreases the adhesion of the scale. Keywords: Pt-Al coating, Hf, Oxidation, Rumpling

  4. Release of fission products from irradiated aluminide fuel at high temperature

    International Nuclear Information System (INIS)

    Shibata, Toshikazu; Kanda, Keiji; Mishima, Kaichiro; Tamai, Tadaharu; Hayashi, Masatoshi; Snelgrove, James L.; Stahl, David; Matos, James E.; Travelli, Armando; Case, F. Neil; Posey, John C.

    1983-01-01

    Irradiated uranium aluminide fuel plates of 40% U-235 enrichment were heated for the determination of fission products released under flowing helium gas at temperatures up to and higher than the melting point of fuel cladding material. The release of fission products from the fuel plate at temperature below 500 deg. C was found negligible. The first rapid release of fission products was observed with the occurrence of blistering at 561±1 deg. C on the plates. The next release at 585. C might be caused by melting of the cladding material of 6061-Al alloy. The last release of fission product gases was occurred at the eutectic temperature of 640 deg. C of U-Al x . The released material was mostly xenon, but small amounts of iodine and cesium were observed. (author)

  5. Simulation and experimental approach to CVD-FBR aluminide coatings on ferritic steels under steam oxidation

    International Nuclear Information System (INIS)

    Leal, J.; Alcala, G.; Bolivar, F.J.; Sanchez, L.; Hierro, M.P.; Perez, F.J.

    2008-01-01

    The ferritic steels used to produce structural components for steam turbines are susceptible to strong corrosion and creep damage due to the extreme working conditions pushed to increase the process efficiency and to reduce pollutants release. The response of aluminide coatings on the P-92 ferritic steel, deposited by CVD-FBR, during oxidation in a simulated steam environment was studied. The analyses were performed at 650 deg. C in order to simulate the working conditions of a steam turbine, and 800 deg. C in order to produce a critical accelerated oxidation test. The Thermo-Calc software was used to predict the different solid phases that could be generated during the oxidation process, in both, coated and uncoated samples. In order to validate the thermodynamic results, the oxides scales produced during steam tests were characterized by different techniques such as XRD, SEM and EDS. The preliminary results obtained are discussed in the present work

  6. Release of fission products from irradiated aluminide fuel at high temperature

    International Nuclear Information System (INIS)

    Shibata, T.; Kanda, K.; Mishima, K.

    1982-01-01

    Irradiated uranium aluminide fuel plates of 40% U-235 enrichment were heated for the determination of fission products released under flowing helium gas at temperatures up to and higher than the melting point of fuel-cladding material. The release of fission products from the fuel plate at temperature below 500 0 C was found negligible. The firist rapid release of fission products was observed with the occurrence of blistering at 561 +- 1 0 C on the plates. The next release at 585 0 C might be caused by melting of the cladding material of 6061-Al alloy. The last release of fission product gases was occurred at the eutectic temperature of 640 0 C of U-Al/sub x/. The released material was mostly xenon, but small amounts of iodine and cesium were observed

  7. Simulation and experimental approach to CVD-FBR aluminide coatings on ferritic steels under steam oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Leal, J. [Universidad Complutense de Madrid, Dep. CC. Materiales e Ingenieria Metalurgica, Avenida Complutense s/n, Facultad de Ciencias Quimicas, 28040 Madrid (Spain); Alcala, G. [Universidad Complutense de Madrid, Dep. CC. Materiales e Ingenieria Metalurgica, Avenida Complutense s/n, Facultad de Ciencias Quimicas, 28040 Madrid (Spain)], E-mail: galcades@yahoo.es; Bolivar, F.J.; Sanchez, L.; Hierro, M.P.; Perez, F.J. [Universidad Complutense de Madrid, Dep. CC. Materiales e Ingenieria Metalurgica, Avenida Complutense s/n, Facultad de Ciencias Quimicas, 28040 Madrid (Spain)

    2008-07-15

    The ferritic steels used to produce structural components for steam turbines are susceptible to strong corrosion and creep damage due to the extreme working conditions pushed to increase the process efficiency and to reduce pollutants release. The response of aluminide coatings on the P-92 ferritic steel, deposited by CVD-FBR, during oxidation in a simulated steam environment was studied. The analyses were performed at 650 deg. C in order to simulate the working conditions of a steam turbine, and 800 deg. C in order to produce a critical accelerated oxidation test. The Thermo-Calc software was used to predict the different solid phases that could be generated during the oxidation process, in both, coated and uncoated samples. In order to validate the thermodynamic results, the oxides scales produced during steam tests were characterized by different techniques such as XRD, SEM and EDS. The preliminary results obtained are discussed in the present work.

  8. Comparison between field and laboratory steam oxidation testing on aluminide coatings on P92

    Energy Technology Data Exchange (ETDEWEB)

    Agueero, A.; Gonzalez, V.; Gutierrez, M. [Instituto Nacional de Tecnica Aeroespacial, Ctra. Ajalvir Km 4, 28850 Torrejon de Ardoz (Spain); Knoedler, R.; Straub, S. [Alstom Power Systems GmbH, Boveristrasse 22, 68309 Mannheim (Germany); Muelas, R. [Ingenieria y Servicios Aeroespaciales, P Pintor Rosales 34, 28008 Madrid (Spain)

    2011-06-15

    Steam oxidation has become an important issue for steam power plants as operating temperatures increase from the current 550 to 600-650 C. For the last 10 years several groups have been carrying out steam oxidation testing of both uncoated substrates and coatings in the laboratory. On the other hand, field testing results are very scarce. In this paper, a comparison of laboratory steam oxidation testing with field test results carried out by Alstom at the Kraftwerk Westfalen power station located in Hamm, Germany will be presented. Both slurry deposited aluminide coatings and uncoated P92 steel have been included in the study. Under steam (atmospheric pressure) and isothermal conditions in the laboratory at 650 C, spallation of oxides formed on ferritic steels occurs after significantly longer time when compared to exposure to real operating conditions. Oxide spallation results in serious damage in steam power plants by obstructing heat exchanger tubes, erosion of valves and turbine blades, etc. Moreover, the thickness of the oxide scales formed under field testing conditions is significantly higher after similar exposure. On the other hand, aluminide coated P92, which exhibit thickness through cracks, have shown to be stable in the laboratory for up to 60 000 h at 650 C under steam, without evidence of crack propagation. However, field test results indicate that some degree of crack propagation occurs but without causing substrate attack up to 21 700 h of exposure. Moreover, the aluminium oxide observed in both laboratory and field tested specimens is different. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Hydrogen permeation rate reduction by post-oxidation of aluminide coatings on DIN 1.4914 martensitic steel (MANET)

    International Nuclear Information System (INIS)

    Perujo, A.; Sample, T.

    1996-01-01

    In a previous work, it has been shown that lower aluminium content aluminide, having the same permeation rate reduction as the higher aluminium content, exhibited a lower hardness and greater ductility and therefore greater crack resistance than the higher aluminium content. In this work we combine this characteristic with a post-oxidation to obtain a further deuterium permeation reduction. The post-oxidation was performed in air at 1023 K for 15 h and at 1223 K for 10 h and 1 h. The maximum deuterium permeation rate reduction obtained is very moderate (maximum of a factor 500 for 1 h at 1223 K) as compared to that of the non-oxidised aluminide specimen (two orders of magnitude) and is constant in the temperature range studied (573-800 K). This method has the technological appeal of using air rather than the controlled environment used by other authors. (orig.)

  10. The obtainment of highly concentrated uranium pellets for plate type (MTR) fuel by dispersion of uranium aluminides in aluminium

    International Nuclear Information System (INIS)

    Morando, R.A.; Raffaeli, H.A.; Balzaretti, D.E.

    1980-01-01

    The use of the intermetallic UAl 3 for manufacturing plate type MTR fuel with 20% U 235 enriched uranium and a density of about 20 kg/m 3 is analyzed. The technique used is the dispersion of UAl 3 particles in aluminium powder. The obtainment of the UAl 3 intermetallic was performed by fusion in an induction furnace in an atmosphere of argon at a pressure of 0.7 BAR (400 mm) using an alumina melting pot. To make the aluminide powder and attain the wished granulometry a cutting and a rotating crusher were used. Aluminide powders of different granulometries and different pressures of compactation were analyzed. In each case the densities were measured. The compacts were colaminated with the 'Picture Frame' technique at temperatures of 490 and 0 deg C with excellent results from the manufacturing view point. (M.E.L.) [es

  11. Microstructure and mechanical properties of Al/Fe-aluminide in-situ composite prepared by reactive stir casting route

    International Nuclear Information System (INIS)

    Chatterjee, Subhranshu; Sinha, Arijit; Das, Debdulal; Ghosh, Sumit; Basumallick, Amitava

    2013-01-01

    Iron aluminide particulate reinforced aluminium composites were prepared by a simple liquid metal stir casting route. The particulate intermetallic reinforcements were formed by in-situ reaction between molten aluminium and a rotating mild steel stirrer at 800 °C. X-ray diffraction studies were carried out to identify the types of iron aluminide particulates present in the as cast composite. Compositional variations of the composite samples were estimated with the aid of energy dispersive spectroscopy. The microstructural features of the composite were studied with respect to different heat treatment schedules and deformation conditions. Microhardness and nanoindentation measurements were also carried out to assess the micromechanical behaviour e.g., hardness and elastic modulus in micrometric length scale of the composite samples. Tensile tests and fractographic analysis were performed to estimate the mechanical properties and determine the mode of failure of the samples. The microstructure and mechanical properties of the composite samples were correlated and discussed

  12. Forthcoming Articles

    Indian Academy of Sciences (India)

    Since January 2016, the Journal of Astrophysics and Astronomy has moved to Continuous Article Publishing (CAP) mode. This means that each accepted article is being published immediately online with DOI and article citation ID with starting page number 1. Articles are also visible in Web of Science immediately.

  13. A Novel Low-Temperature Fiffusion Aluminide Coating for Ultrasupercritical Coal-Fried Boiler Applications

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ying

    2009-12-31

    An ultrasupercritical (USC) boiler with higher steam temperature and pressure is expected to increase the efficiency of the coal-fired power plant and also decrease emissions of air pollutants. Ferritic/martensitic alloys have been developed with good creep strength for the key components in coal-fired USC plants. However, they typically suffer excessive steam-side oxidation, which contributes to one of main degradation mechanisms along with the fire-side corrosion in coal-fired boilers. As the steam temperature further increases in USC boilers, oxidation of the tube internals becomes an increasing concern, and protective coatings such as aluminide-based diffusion coatings need to be considered. However, conventional aluminizing processes via pack cementation or chemical vapor deposition are typically carried out at elevated temperatures (1000-1150 C). Thermochemical treatment of ferritic/martensitic alloys at such high temperatures could severely degrade their mechanical properties, particularly the alloy's creep resistance. The research focus of this project was to develop an aluminide coating with good oxidation resistance at temperatures {le} 700 C so that the coating processing would not detrimentally alter the creep performance of the ferritic/martensitic alloys. Nevertheless, when the aluminizing temperature is lowered, brittle Al-rich intermetallic phases, such as Fe{sub 2}Al{sub 5} and FeAl{sub 3}, tend to form in the coating, which may reduce the resistance to fatigue cracking. Al-containing binary masteralloys were selected based on thermodynamic calculations to reduce the Al activity in the pack cementation process and thus to prevent the formation of brittle Al-rich intermetallic phases. Thermodynamic computations were carried out using commercial software HSC 5.0 for a series of packs containing various Cr-Al binary masteralloys. The calculation results indicate that the equilibrium partial pressures of Al halides at 700 C were a function of Al

  14. Preparation of aluminide coatings on the inner surface of tubes by heat treatment of Al coatings electrodeposited from an ionic liquid

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Dongpeng; Chen, Yimin [School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Ling, Guoping, E-mail: linggp@zju.edu.cn [School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Liu, Kezhao; Chen, Chang’an; Zhang, Guikai [National Key Laboratory of Surface Physics, China Academy of Engineering Physics, Mianyang 621900 (China)

    2015-12-15

    Highlights: • Al coating is prepared on the inner surface of one-meter tube. • Al coating shows good adherence to the substrate. • The thickness of Al coating is uniform along the tube. • Aluminide coating is obtained by heat treating Al coating. • Structure of aluminide coating is regulated by different thickness of Al coating. - Abstract: Aluminide coatings were prepared on the inner surface of 316L stainless steel tubes with size of Ø 12 mm × 1000 mm by heat-treating Al coatings electrodeposited from AlCl{sub 3}-1-ethyl-3-methyl-imidazolium chloride (AlCl{sub 3}–EMIC) ionic liquid at room temperature. Studies on the electrolytic etching pretreatment of stainless tubes before Al coating electrodeposition were carried out. The Al coating showed good adherence to the substrate after electrolytic etching at 10 mA/cm{sup 2} for 10 min. The thickness of Al coatings was uniform along the tube. The structure of prepared aluminide coatings can be regulated by different thickness of Al coating. The outer layer of aluminide coatings was FeAl, Fe{sub 2}Al{sub 5} and FeAl{sub 3} for the samples of 1-μm, 5-μm and 10-μm thick Al coatings, respectively.

  15. Are clinical findings of systemic titanium dispersion following implantation explained by available in vitro evidence? An evidence-based analysis.

    Science.gov (United States)

    Curtin, Justin Paul; Wang, Minji

    2017-08-01

    Although the presence of titanium wear particles released into tissues is known to induce local inflammation following the therapeutic implantation of titanium devices into humans, the role that titanium ions play in adverse tissue responses has received little attention. Support that ongoing titanium ion release occurs is evidenced by the presence of ionic titanium bound to transferrin in blood, and ongoing excretion in the urine of patients with titanium devices. However, as reports documenting the presence of titanium within tissues do not distinguish between particulate and ionic forms due to technical challenges, the degree to which ionic titanium is released into tissues is unknown. To determine the potential for titanium ion release into tissues, this study evaluates available in vitro evidence relating to the release of ionic titanium under physiological conditions. This is a systematic literature review of studies reporting titanium ion release into solutions from titanium devices under conditions replicating the interstitial pH and constituents. Inclusion and exclusion criteria were defined. Of 452 articles identified, titanium ions were reported in nine media relevant to human biology in seventeen studies. Only one study, using human serum replicated both physiological pH and the concentration of constituents while reporting the presence of titanium ions. While there is insufficient information to explain the factors that contribute to the presence of titanium ions in serum of humans implanted with titanium devices, currently available information suggests that areas of future inquiry include the role of transferrin and organic acids.

  16. Classification of titanium dioxide

    International Nuclear Information System (INIS)

    Macias B, L.R.; Garcia C, R.M.; Maya M, M.E.; Ita T, A. De; Palacios G, J.

    2002-01-01

    In this work the X-ray diffraction (XRD), Scanning Electron Microscopy (Sem) and the X-ray Dispersive Energy Spectroscopy techniques are used with the purpose to achieve a complete identification of phases and mixture of phases of a crystalline material as titanium dioxide. The problem for solving consists of being able to distinguish a sample of titanium dioxide being different than a titanium dioxide pigment. A standard sample of titanium dioxide with NIST certificate is used, which indicates a purity of 99.74% for the TiO 2 . The following way is recommended to proceed: a)To make an analysis by means of X-ray diffraction technique to the sample of titanium dioxide pigment and on the standard of titanium dioxide waiting not find differences. b) To make a chemical analysis by the X-ray Dispersive Energy Spectroscopy via in a microscope, taking advantage of the high vacuum since it is oxygen which is analysed and if it is concluded that the aluminium oxide appears in a greater proportion to 1% it is established that is a titanium dioxide pigment, but if it is lesser then it will be only titanium dioxide. This type of analysis is an application of the nuclear techniques useful for the tariff classification of merchandise which is considered as of difficult recognition. (Author)

  17. Opportunities in the electrowinning of molten titanium from titanium dioxide

    CSIR Research Space (South Africa)

    Van Vuuren, DS

    2005-10-01

    Full Text Available The value chain of titanium products shows that the difference between the cost of titanium ingot and titanium dioxide is about $9/kg titanium. In contrast, the price of aluminum, which is produced in a similar way, is only about $1.7/kg...

  18. In-Pile Experiment of a New Hafnium Aluminide Composite Material to Enable Fast Neutron Testing in the Advanced Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Donna Post Guillen; Douglas L. Porter; James R. Parry; Heng Ban

    2010-06-01

    A new hafnium aluminide composite material is being developed as a key component in a Boosted Fast Flux Loop (BFFL) system designed to provide fast neutron flux test capability in the Advanced Test Reactor. An absorber block comprised of hafnium aluminide (Al3Hf) particles (~23% by volume) dispersed in an aluminum matrix can absorb thermal neutrons and transfer heat from the experiment to pressurized water cooling channels. However, the thermophysical properties, such as thermal conductivity, of this material and the effect of irradiation are not known. This paper describes the design of an in-pile experiment to obtain such data to enable design and optimization of the BFFL neutron filter.

  19. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. PREVALENCE OF ANDROGENIC-. ANABOLIC STEROID USE IN. ADOLESCENTS IN TWO REGIONS. OF SOUTH AFRICA. Michael I lambert, Steven D Titlestad, Martin P Schwellnus. Objective. To determine the prevalence of androgenic- anabolic steroid (AAS) use among schoolchildren in two.

  20. SERIES ARTICLES

    Indian Academy of Sciences (India)

    ensis fruit. 4. SERIES ARTICLES. Evolution of the Atmosphere and Oceans: Evidence from Geological Records. Evolution of the Early Atmosphere. P V Sukumaran. 11 Electrostatics in Chemistry. Electrostatic Models for Weak Molecular ...

  1. SERIES ARTICLES

    Indian Academy of Sciences (India)

    IAS Admin

    347 Impact of Theoretical Chemistry on Chemical and. Biological Sciences. Chemistry Nobel Prize – 2013. Saraswathi Vishveshwara. SERIES ARTICLES. 368 Ecology: From Individuals to Collectives. A Physicist's Perspective on Ecology. Vishwesha Guttal. 310. 368 ...

  2. Machinability of Titanium Alloys

    Science.gov (United States)

    Rahman, Mustafizur; Wong, Yoke San; Zareena, A. Rahmath

    Titanium and its alloys find wide application in many industries because of their excellent and unique combination of high strength-to-weight ratio and high resistance to corrosion. The machinability of titanium and its alloys is impaired by its high chemical reactivity, low modulus of elasticity and low thermal conductivity. A number of literatures on machining of titanium alloys with conventional tools and advanced cutting tool materials is reviewed. The results obtained from the study on high speed machining of Ti-6Al-4V alloys with cubic boron nitride (CBN), binderless cubic boron nitride (BCBN) and polycrystalline diamond (PCD) are also summarized.

  3. Production of titanium tetrachloride

    International Nuclear Information System (INIS)

    Perillo, P.M.; Botbol, O.

    1990-01-01

    This report presents a summary of results from theoperation of a laboratory scale for the production in batches of approximately 100 gs of titanium tetrachloride by chlorination with chloroform and carbon tetrachloride between 340 deg C and 540 deg C. Chlorination agent vapors were passed through a quartz column reacting with titanium oxide powder agglomerated in little spheres. Obtained titanium tetrachloride was condensed in a condenser, taken in a ballon and then purified by fractional distillation. Optimun temperature for chloroform was 400 deg C with 74 % yield and for carbon tetrachloride was 500 deg C with 69 % yield. (Author) [es

  4. Processing of spent pickling liquor formed during treatment of titanium products

    Science.gov (United States)

    Bykovsky, N. A.; Rahman, P. A.; Puchkova, L. N.; Fanakova, N. N.

    2017-10-01

    The article presents the research findings on processing of spent acid pickling liquor (SAPL) formed during etching of titanium products. The processing includes neutralizing the SAPL with alkali, filtering, drying and calcining the titanium hydroxide precipitate as well as electrochemical processing of the filtrate in an ion-exchange membrane cell. The proposed SAPL processing procedure allows obtaining titanium dioxide, sodium hydroxide and a mixture of acids. Titanium dioxide can be used in paint-and-varnish industry. The alkali can be used in neutralizing the SAPL. A mixture of acids is suitable for use in etching process of titanium products.

  5. Laminate article

    Science.gov (United States)

    Williams, Robert K.; Paranthaman, Mariappan; Chirayil, Thomas G.; Lee, Dominic F.; Goyal, Amit; Feenstra, Roeland

    2002-01-01

    A laminate article comprises a substrate and a biaxially textured (RE.sub.x A.sub.(1-x)).sub.2 O.sub.2-(x/2) buffer layer over the substrate, wherein 0article can include a layer of YBCO over the (RE.sub.x A.sub.(1-x)).sub.2 O.sub.2-(x/2) buffer layer. A layer of CeO.sub.2 between the YBCO layer and the (RE.sub.x A.sub.(1-x)).sub.2 O.sub.2-(x/2) buffer layer can also be include. Further included can be a layer of YSZ between the CeO.sub.2 layer and the (RE.sub.x A.sub.(1-x)).sub.2 O.sub.2-(x/2) buffer layer. The substrate can be a biaxially textured metal, such as nickel. A method of forming the laminate article is also disclosed.

  6. 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.

  7. Review article

    DEFF Research Database (Denmark)

    Karsdal, Morten Asser; Krarup, H; Sand, J M B

    2014-01-01

    and to facilitate improved drug development. The aim of this article was to review the serological biomarkers that may assist in early diagnosis of patients, separate fast from slow- or nonprogressors, and possibly assist in drug development for fibroproliferative diseases, exemplified by liver fibrosis. The lack...... of success of biochemical markers and the possible reasons for this is discussed in the context of other fields with biomarker success. METHOD: This is a personal opinion review article. RESULTS: Biochemical markers, originating from the fibrotic structure, may have increased specificity and sensitivity...

  8. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. FIREARM-RELATED INJURIES AND. DEATHS AMONG CHILDREN AND. ADOLESCENTS IN CAPE TOWN -. 1992 -1996. Alyssa Wigton. Objective. To determ.i.lle the epidemiological profile of fireann- related injuries among children and adolescents in Cape. Town during recent years in order to ...

  9. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. References. 1. UNAIDS. Report on the Global HTV/AIDS Epidemic. Geneva: June 2000. 2. Connor E..\\1, Sperling RS, Gelber R. et al. Reduction of maternal-infant transmission of human immunodeficiency virus type 1 with zidovu dine treatment. N Eng! J Med 1994; 331:1173-1180. 3. Undegren ML ...

  10. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. PEAK RATES OF DIURESIS IN. HEALTHY HUMANS DURING ORAL. FLUID OVERLOAD. Timothy D Noakes, Gary Wilson, David A Gray,. Michael I Lambert, Steven C Dennis. Objective. To determine whether rates of intestinal fluid absorption and renal diuresis can match high rates of fluid ingestion ...

  11. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. CRITICAL CARE FOCUS. AETIOLOGY AND OUTCOME OF. SEVERE COMMUNITY-ACQUIRED. PNEUMONIA IN CHILDREN. ADMITTED TO A PAEDIATRIC. INTENSIVE CARE UNIT. S D Delport, T Brisley. Objective. To determine the aetiological agents and outcome of severe community-acquired ...

  12. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. UNPAID COMMUNITY. VOLUNTEERS - EFFECTIVE. PROVIDERS OF DIRECTLY. OBSERVED THERAPY (DOT) IN. RURAL SOUTH AFRICA. R D Barker, F J C Millard, M E Nthangeni. Objective. To il).ustrate successes and difficulties for the South. African National Tuberculosis Progranune in a ...

  13. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. Dual protection in sexually active women. Immo Kleinschmidt, Baker Ndugga Maggwa, Jennifer Smit,Mags E Beksinska, Helen Rees. Objective. To determine the prevalence and co-factors associated with the practice of dual protection against sexually transmitted infections (STis) and unwanted.

  14. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. EARLY DIAGNOSIS OF PROSTATE. CANCER IN THE WESTERN CAPE. C F Heyns, AM Naude, A J Visser, D C Marais,. H B Stopforth, J K Nyarko, G A Stellmacher. Background. Early stage prostate cancer does not cause symptoms, and even metastatic disease may exist for years without causing ...

  15. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. Nutritional variation and cardiovascular risk factors in. Tanzania - rural-urban difference. Marina Njelekela, Toshiaki Sato, Yasuo Nara, Tomohiro Miki, Sachiko Kuga, Takanori Noguchi, Torno Kanda, Masashi Yamori,. Josiah Ntogwisangu, Zablon Masesa, Yohana Mashalla, Jacob Mtabaji, Yukio ...

  16. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. Formative assessment promotes learning in undergraduate clinical clerkships. V C Burch, J L Seggie, N E Gary. Introduction. Clinical clerkships, typically situated in environments lacking educational structure, form the backbone of undergraduate medical training. The imperative to develop strategies ...

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    African Journals Online (AJOL)

    ORIGINAL ARTICLES c(~rvical spine injury outcome- a review of 101 cases treated in a tertiary referral unit. K Friielingsdorf, R N Dunn. Cervical spinal cord injury (SCI) is a devastating event for the patient and family. It has a huge impact on society because of the intensive resources required to manage the patient in both.

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    African Journals Online (AJOL)

    ORIGINAL ARTICLES. OCCUPATIONAL EXPOSURE OF. INTERNS TO BLOOD IN AN AREA. OF HIGH HIV SEROPREVALENCE. A S Karstaedt, L Pantanowitz. Objective. To determine the epidemiology of work-related exposure to blood among interns. Design. Interns were invited to complete anonymously a questionnaire ...

  19. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. HISTORY OF MEDICINE. ELIM HOSPITAL - THE FIRST 100. YEARS. Part 2. C F van der Merwe. THE JAQUES ERA. The year 1957 saw the arrival of another giant in the history of. Elim Hospital. During this year Dr Pierre Jaques returned from postgraduate work in the UK. This son of the North was.

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    African Journals Online (AJOL)

    ORIGINAL ARTICLES. References. 1. Raftery J. Mental health services in transition: the United States and the United Kingdom. Br. J Psychiatry 1992; 161: 589-593. 2. Sainsbury Centre for Mental Health. The Mental Health Services Workforce: Present and Future. A Report for the NHS Executive. London: The Sainsbury ...

  1. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. NUTRITIONAL STATUS AND. DENTAL CARIES IN A LARGE. SAMPLE OF 4- AND 5-YEAR-OLD. SOUTH AFRICAN CHILDREN. Peter Cleaton-Jones, Barbara D Richardson, Lars Granath,. L raul Fatti, Ruth SinweU, Alexander R Walker, Mirriam. Mogotsi. Background. Evidence from studies involving ...

  2. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. WHAT IS THE INFANT MORTALITY. RATE IN SOUTH AFRICA? THE NEED FOR IMPROVED DATA. Nadine Nannan, Debbie Bradshaw, Robert Mazur, Sim.phiwe. Maphumulo. Objectives. To review recent infant mortality and birth registration data in South Africa and to investigate geographical ...

  3. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    1997-06-17

    Jun 17, 1997 ... Steve Reid and Janet Giddy are two family physicians who worked from 1986 to 1995 at Bethesda Hospital in Ubombo,. Northern KwaZulu-Nata!. This article, which has been adapted from their submission to the Truth and Reconciliation. Commission (TRC) Health Sector Hearings on 17 June 1997,.

  4. Research Article

    African Journals Online (AJOL)

    2017-01-01

    Jan 1, 2017 ... the atomic level and to the experimental data. The purpose of this article is to fill this gap and to provide a more detailed and well-grounded substantial model of the photon. We will do it based on the theory of infinite nesting of matter and the substantial model of the electron [9]. We will start with considering ...

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    African Journals Online (AJOL)

    2016-06-11

    Jun 11, 2016 ... n this article we try to explain the usage of tie-and-strut method a g this method in design of ... economical usage and ability to using them repeatedly (formwork system), the possibility of using the larger .... connecting regions have sufficient plastic deformation capacity, understanding of its behaviour will be ...

  6. Review Article

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    Evert

    Vast hiatuses therefore exist in the South African historiography surrounding the First World. War and the role played by Union troops in it.4 This article reports on a review of the military archival holdings of the Documentation Centre in the light of these hiatuses. Deneys Reitz (1882–1944), third son of a former president of ...

  7. ORIGINAL ARTICLE

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    boaz

    ORIGINAL ARTICLE. AFRICAN JOURNAL OF CLINICAL AND EXPERIMENTAL MICROBIOLOGY MAY 2017 ISBN 1595-689X VOL18 No. 2 ... aquaculture in particular is of great concern to environmental and public health. In Nigeria, regulation ..... Occupational and Environmental Hygiene, 7 (2): 66-71. 29. Adebowale O.O ...

  8. Original Article

    African Journals Online (AJOL)

    Administratör

    Stroke in Palestine www.ljm.org.ly. Libyan J Med, AOP: 080920. Page 39. Original Article. Characterization of Hospitalized Ischemic Stroke Patients in. Palestine. Sawalha AF ... Key words: Ischemic stroke, Risk factors, In-hospital mortality, Palestine. ABSTRACT .... stroke in young patients seems to vary between different ...

  9. Research Article

    African Journals Online (AJOL)

    2016-06-25

    Jun 25, 2016 ... This article aims at evaluating the fun oftware which are employed for approximate solution in optimization been produced least squares by usual methods for linear and non enetic algorithm in this research. t Squares, Genetic Algorithm, Linear Model, Nonlinear Model, S dence, e-mail: c.author@mail.com.

  10. SERIES ARTICLES

    Indian Academy of Sciences (India)

    T Padmanabhan. GENERAL ARTICLES. 441 Bernoulli Runs Using 'Book Cricket' to Evaluate. Cricketers. Anand Ramalingam. 454 Wilhelm Ostwald, the Father of Physical Chemistry. Deepika Janakiraman. 468 How Many Equivalent Resistances? Sameen Ahmed Khan. 476 Multiplication: From Thales to Lie. P H Keskar.

  11. SERIES ARTICLES

    Indian Academy of Sciences (India)

    IAS Admin

    Tanya Kaushal Srivastava. 1086 Stochastic Approximation. Vivek S Borkar. 1095 False Discovery Rates and Multiple Testing. Soumen Dey and Mohan Delampady. SERIES ARTICLES. 1110 Challenges in the Quest for Clean Energies. Other Renewable Resources and Conclusion. Sheela K Ramasesha. 1095. 1110.

  12. SERIES ARTICLES

    Indian Academy of Sciences (India)

    304 Dawn of Science. The Copernican Revolution. T Padmanabhan. GENERAL ARTICLES. 310 Mach's Principle. J V Narlikar. 322 Robert Dicke and Atomic Physics. Vasant Natarajan. 333 Decoding Non-Coding DNA: Trash or Treasure? Namrata Iyer. 341 Weierstrass's Theorem – Leaving no 'Stone' Unturned. B Sury.

  13. SERIES ARTICLES

    Indian Academy of Sciences (India)

    This is the recent image of the microwave background and a 'shadow' (in bright colours) cast by a nearby galaxy cluster, as predicted in. 1969 by Zeldovich and his student Sunyaev. (refer to the article on p.428). Image courtesy: European Space Agency. Ya B Zeldovich. (1914–1987). ( Illustration: Subhankar Biswas ).

  14. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES failure, breath-holding spells and even strokeY The decreased attention span and learning associated with iron deficiency may have adverse effects on cognitive and psychomotor development.'-' Furthermore, appropriate treatment of iron deficiency is effective and safe, It would therefore seem worth.

  15. REVIEW ARTICLE

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    User

    To conduct this review, we searched for relevant articles indexed in certain databases such as PubMed, Scopus, Islamic ... disorder characterized by disproportionate amount of urine excreted while asleep (Farhat et al., 2000). ... reported to be the causes of this disorder (Behrman. E.R, 2007). Nocturnal enuresis in children ...

  16. SERIES ARTICLES

    Indian Academy of Sciences (India)

    RESONANCE | June 2011. Resonance journal of science education. June 2011 Volume 16 Number 6. GENERAL ARTICLES. 504 D D Kosambi: The Scholar ... 551 Early Indian History and the Legacy of D D Kosambi. Romila Thapar. Source: http://www.arvindguptatoys. com/arvindgupta/ddknumis- matics.pdf. Punch Mark.

  17. Research Article

    African Journals Online (AJOL)

    2016-06-18

    Jun 18, 2016 ... Research Article. Journal of Fundamental and Applied Sciences is licensed under a Creative Commons Attribution-NonCommercial 4.0. International ... and breakthrough for human not only in some location and for some year rather for the ... they are used for the new source for building a new structure.

  18. SERIES ARTICLES

    Indian Academy of Sciences (India)

    From Euclid to Soccer if is ... A R Rao. Chemical Research of Sir Prafulla Chandra Ray. Sreebrata Goswami and Samaresh Bhattacharya. Acharya Prafulla Chandra at the College of Science. Gurunath Mukherjee. FEATURE ARTICLES. 54 Nature Watch. Engimatic Bamboos. C K John and Rajani 5 Nadgauda.

  19. ORIGINAL ARTICLES

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    remarkable history. The aim of this article is to share with the reader some of the events that led to the establishment of this institution and to recount the achievements of its staff through more than 100 years of history. ... The remarkable story of their arrival in .... longer seen as role models and they had to change their policy,.

  20. Research Article

    African Journals Online (AJOL)

    2016-06-13

    Jun 13, 2016 ... emerging drug-resistant pathogens in research programme around the world. This article reviews the .... classes are as follows: a) ß-Lactams (Penicillins, Cephalosporins, Monobactams and Carbapenems) .... Vancomycin Resistant Enterococci (VRE), Pseudomonas aeruginosa and Candida albicans, etc.

  1. SERIES ARTICLES

    Indian Academy of Sciences (India)

    IAS Admin

    Inside Back Cover. Flowering Trees. (Credit: K Sankara Rao, IISc) ifference using CROs by Lissajous Method. Article-in-a-Box. John Dalton. S Natarajan. 2. Classroom. The Importance of. Selecting Suitable Com- ponents and Apparatus in Physics Laboratories. Vijay H Raybagkar. 76. Classics. On the Constitution of Bodies.

  2. REVIEW ARTICLE

    Indian Academy of Sciences (India)

    The article is aimed to review the impact of endogenous and exogenous factors on a mechanistic pathway of organophosphate pesticide biotransformation and various risk associated with it among the human population. Understanding the genetic polymorphism of genes involved in pesticide metabolism and highlighting ...

  3. Review Article

    African Journals Online (AJOL)

    2012-09-15

    Sep 15, 2012 ... Effects of Cheating on Accurate Assessment. Deepika Nelson, Julia Devardhi and Abdulaziz Dino. School of Foreign Language Studies, Main Campus, Post Box No: 53, Haramaya University, Ethiopia. Abstract. Article Information. In the view of Boud and Falchikov (2006) assessment has the clear purpose ...

  4. Download article

    African Journals Online (AJOL)

    user

    tions made in this article about outer texts in an electronic sign language dictionary serve as part of a complete concept model suggested specifically for the De la Bat School for the Deaf in Worcester,. South Africa (Fourie 2013). The purpose of the proposed dictionary is to give the learners of the De la Bat School electronic ...

  5. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. Paediatric immunity. The immaturity of the infant immune system is demonstrated by the increased susceptibility of children to infections by both viral and bacterial pathogens. The humoral arm of the immune system is underdeveloped and differs greatly from that of adults. Infants only develop the ...

  6. RESEARCH ARTICLE

    Indian Academy of Sciences (India)

    USER

    RESEARCH ARTICLE. Loss of smooth muscle myosin heavy chain results in the bladder and stomach developing lesion during mouse fetal development in mice. Running title. Bladder and stomach lesion without SM-MHC. MEIJUAN LI, SHILI LI, YU RAO, SHENG CUI, KEMIAN GOU*. State Key Laboratory of ...

  7. RESEARCH ARTICLE

    Indian Academy of Sciences (India)

    Navya

    RESEARCH ARTICLE. Expression analysis of Argonaute, Dicer-like and .... provided a foundation for future functional genomics studies of transcriptional silencing-associated gene families in ..... developmental and stress responses, antiviral immune responses and chromatin structure. These genes can affect the growth, ...

  8. Research Article

    African Journals Online (AJOL)

    SAMSUNG

    2016-06-05

    Jun 5, 2016 ... for civil engineers (in terms of gravity and lateral load) in developed countries. Despite the relatively significant growth of LSF structures during the last decade in our country, the studies in this field have been still done neither in our country nor in abroad. In this article, we try to study LSF structures from the ...

  9. Review Article

    African Journals Online (AJOL)

    2007-12-02

    Dec 2, 2007 ... Introduction. What prompted this review article is because of the wrong notion that the only standard abdominal incision is the midline incision. Cases have been seen in which an abdominal incision extends from the xyphoid process to the symphysis pubis just to remove a perforated appendix! The reason ...

  10. Original Article

    African Journals Online (AJOL)

    2010 May;3(2):25-9. Original Article. AJNT. Abstract. Introduction: Several reports described an association between type 2 diabetes mellitus (DM) and chronic hepatitis C virus (HCV) infection. Chronic HCV infection is prevalent in Egypt. The present work aimed to evaluate the prevalence of proteinuria and neuropathy.

  11. Titanium by design: TRIP titanium alloy

    Science.gov (United States)

    Tran, Jamie

    Motivated by the prospect of lower cost Ti production processes, new directions in Ti alloy design were explored for naval and automotive applications. Building on the experience of the Steel Research Group at Northwestern University, an analogous design process was taken with titanium. As a new project, essential kinetic databases and models were developed for the design process and used to create a prototype design. Diffusion kinetic models were developed to predict the change in phase compositions and microstructure during heat treatment. Combining a mobility database created in this research with a licensed thermodynamic database, ThermoCalc and DICTRA software was used to model kinetic compositional changes in titanium alloys. Experimental diffusion couples were created and compared to DICTRA simulations to refine mobility parameters in the titanium mobility database. The software and database were able to predict homogenization times and the beta→alpha plate thickening kinetics during cooling in the near-alpha Ti5111 alloy. The results of these models were compared to LEAP microanalysis and found to be in reasonable agreement. Powder metallurgy was explored using SPS at GM R&D to reduce the cost of titanium alloys. Fully dense Ti5111 alloys were produced and achieved similar microstructures to wrought Ti5111. High levels of oxygen in these alloys increased the strength while reducing the ductility. Preliminary Ti5111+Y alloys were created, where yttrium additions successfully gettered excess oxygen to create oxides. However, undesirable large oxides formed, indicating more research is needed into the homogeneous distribution of the yttrium powder to create finer oxides. Principles established in steels were used to optimize the beta phase transformation stability for martensite transformation toughening in titanium alloys. The Olson-Cohen kinetic model is calibrated to shear strains in titanium. A frictional work database is established for common alloying

  12. Theoretical studies of aluminum and aluminide alloys using CALPHAD and first-principles approach

    Science.gov (United States)

    Jiang, Chao

    Heat-treatable aluminum alloys have been widely used in the automobile and aerospace industries as structural materials due to their light weight and high strength. To study the age-hardening process in heat-treatable aluminum alloys, the Gibbs energies of the strengthening metastable phases, e.g. theta ' and theta″, are critical. However, those data are not included in the existing thermodynamic databases for aluminum alloys due to the semi-empirical nature of the CALPHAD approach. In the present study, the thermodynamics of the Al-Cu system, the pivotal age-hardening system, is remodeled using a combined CALPHAD and first-principles approach. The formation enthalpies and vibrational formation entropies of the stable and metastable phases in the Al-Cu system are provided by first-principles calculations. Special Quasirandom Structures (SQS's) are applied to model the substitutionally random fee and bee alloys. SQS's for binary bee alloys are developed and tested in the present study. Finally, a self-consistent thermodynamic description of the Al-Cu system including the two metastable theta″ and theta' phases is obtained. During welding of heat-treatable aluminum alloys, a detrimental phenomenon called constitutional liquation, i.e. the local eutectic melting of second-phase particles in a matrix at temperatures above the eutectic temperature but below the solidus of the alloy, may occur in the heat-affected zone (HAZ). In the present study, diffusion code DICTRA coupled with realistic thermodynamic and kinetic databases is used to simulate the constitutional liquation in the model Al-Cu system. The simulated results are in quantitative agreement with experiments. The critical heating rate to avoid constitutional liquation is also determined through computer simulations. Besides the heat-treatable aluminum alloys, intermetallic compounds based on transition metal aluminides, e.g. NiAl and FeAl, are also promising candidates for the next-generation of high

  13. Qualification of high density aluminide fuels for the BR2 reactor

    International Nuclear Information System (INIS)

    Beeckmans de West-Meerbeeck, Andre; Gubel, Pol; Ponsard, Bernard; Pin, Thomas; Falgoux, Jean Louis

    2005-01-01

    The BR2 operation still relies on the use of 90..93% enriched HEU aluminide fuel. The availability of a limited batch of 73% enriched HEU from reprocessed BR2 uranium in Dounreay justified 10 years ago the qualification and use of this material. After some preliminary test irradiations, various batches of fuel elements were fabricated by the UKAEA-Dounreay and successfully irradiated. Due to their lower 235 U content (0.050 g 235 U/cm 2 ), these elements were always irradiated together with standard 90...93% HEU fuel elements. A mixed-core strategy was developed at this occasion for an optimal utilization, and was reported during the 4th RRFM conference (March 19-21, 2000, Colmar, France). The availability of a new batch of fresh 73% HEU material was the occasion, a few years ago, to initiate the development, fabrication and qualification of a new high density fuel element. An order was placed with CERCA to assess the optimal fabrication methods and tooling required to meet as far as possible the existing BR2 standard specifications and 235 U content (0.060 g 235 U/cm 2 ). This development phase has been already reported during the 7th RRFM conference (March 9-12, 2003, Aix-en-Provence, France). Afterwards, six lead test fuel elements were ordered for qualification by irradiation. The neutronic properties of the fuel elements were adjusted and optimized. After a short summary of the main results of the development program, this paper describes the nuclear characteristics of the high density fuel elements and comments on the nuclear follow-up of the lead test fuel elements during their irradiation for five cycles in the BR2 reactor and the return of experience for CERCA. (author)

  14. Protective articles

    International Nuclear Information System (INIS)

    Wardley, R.B.

    1983-01-01

    This patent specification describes an article affording protection against radiation, and especially against X-rays comprising at least one flexible layer of lead filled material in an envelope of, or sandwiched between two layers of a knitted, woven or non-woven fabric preferably of synthetic fibrous material, carrying on its outer surface a coating of flexible polyurethane. The outer fabric provides a resilient, extremely tough and cut resistant covering for the relatively soft lead filled material. (author)

  15. Environmental effect of S02-bearing atmosphere on the creep fatigue failure of aluminide-coated MM-002 nickel-base superalloy at 870°C

    CSIR Research Space (South Africa)

    Aghion, E

    1995-04-15

    Full Text Available High-temperature low-cycle fatigue (HTLCF) failure mechanisms of aluminide-coated MAR-M002 nickel-base superalloy in air, argon and Ar+5% SO2 atmospheres were investigated at 870°C. The loading conditions were constant and consisted of creep tension...

  16. The use of titanium and stainless steel in fracture fixation.

    Science.gov (United States)

    Hayes, J S; Richards, R G

    2010-11-01

    The use of metal in fracture fixation has demonstrated unrivalled success for many years owing to its high stiffness, strength, biological toleration and overall reliable function. The most prominent materials used are electropolished stainless steel and commercially pure titanium, along with the more recent emergence of titanium alloys. Despite the many differences between electropolished stainless steel and titanium, both materials provide a relatively predictable clinical outcome, and offer similar success for fulfilling the main biomechanical and biological requirements of fracture fixation despite distinctive differences in implant properties and biological responses. This article explores these differences by highlighting the limitations and advantages of both materials, and addresses how this translates to clinical success.

  17. Formation of aluminide coatings by low-temperature heat treatment of Al coating electrodeposited from ionic liquid

    International Nuclear Information System (INIS)

    Li Yan; Xu Bajin; Ling Guoping; Liu Kezhao; Chen Chang'an; Zhang Guikai

    2011-01-01

    In this study, we proposed a two-step approach to prepare aluminide coatings, namely electrodepositing Al from AlCl 3 -1-ethyl-3-methyl-imidazolium chloride (AlCl 3 -EMIC) ionic liquid at room temperature and subsequent heat treatment at low temperature. The adherence of the coating was checked by a simple mechanical scratch test. The surface and cross-sectional morphologies, phase structures and chemical compositions of the coatings after heat treatment were characterized by scanning electronic microscope (SEM), X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDX), respectively. The deposited Al coatings were in homogenous and controllable thickness with excellent adherence to the substrate. The coatings were brittle Fe 2 Al 5 and FeAl 3 phase after 5 min heat treatment at 670 deg. C, which transformed into ductile FeAl phase after 16 h heat treatment. The advantages of this method in eliminating the brittle Fe 2 Al 5 , cracks and pores in the aluminide coatings were discussed.

  18. Preparation of titanium diboride powders from titanium alkoxide and ...

    Indian Academy of Sciences (India)

    Titanium diboride powders were prepared through a sol–gel and boron carbide reduction route by using TTIP and B4C as titanium and boron sources. The influence of TTIP concentration, reaction temperature and molar ratio of precursors on the synthesis of titanium diboride was investigated. Three different concentrations ...

  19. Communications article

    KAUST Repository

    Fariborzi, Hossein

    2017-07-20

    Seamless, covert communications using a communications system integrated or incorporated within an article of clothing is described. In one embodiment, the communications system is integrated or incorporated into a shoe insole and includes a haptic feedback mechanism, a communications module, a flexible pressure sensor, and a battery. The communications module includes a wireless communications module for wireless communications, a wired interface for wired communications, a microcontroller, and a battery charge controller. The flexible pressure sensor can be actuated by an individual\\'s toe, for example, and communication between two communications nodes can be achieved using coded signals sent by individuals using a combination of long and short presses on the pressure sensor. In response to the presses, wireless communications modules can transmit and receive coded signals based on the presses.

  20. Rheological assessment of titanium MIM feedstocks [Journal article

    CSIR Research Space (South Africa)

    Benson, JM

    2011-03-01

    Full Text Available remelting and forming operations can then be avoided, except in the manufacture of large components. Metal injection moulding (MIM) is an effective process for producing complex net-shape components in large volumes from metal powders. Nevertheless...

  1. Titanium metal: extraction to application

    Energy Technology Data Exchange (ETDEWEB)

    Gambogi, Joseph (USGS, Reston, VA); Gerdemann, Stephen J.

    2002-09-01

    In 1998, approximately 57,000 tons of titanium metal was consumed in the form of mill products (1). Only about 5% of the 4 million tons of titanium minerals consumed each year is used to produce titanium metal, with the remainder primarily used to produce titanium dioxide pigment. Titanium metal production is primarily based on the direct chlorination of rutile to produce titanium tetrachloride, which is then reduced to metal using the Kroll magnesium reduction process. The use of titanium is tied to its high strength-to-weight ratio and corrosion resistance. Aerospace is the largest application for titanium. In this paper, we discuss all aspects of the titanium industry from ore deposits through extraction to present and future applications. The methods of both primary (mining of ore, extraction, and purification) and secondary (forming and machining) operations will be analyzed. The chemical and physical properties of titanium metal will be briefly examined. Present and future applications for titanium will be discussed. Finally, the economics of titanium metal production also are analyzed as well as the advantages and disadvantages of various alternative extraction methods.

  2. Industrial experience with titanium

    International Nuclear Information System (INIS)

    Ikeda, B.M.; Shoesmith, D.W.

    1997-09-01

    Titanium is a reference material for the construction of waste containers in the Canadian Nuclear Fuel Waste Management Program. It has been in industrial service for over 30 a, often in severe corrosion environments, but it is still considered a relatively exotic material with limited operating history. This has arisen because of the aerospace applications of this material and the misconception that the high strength-to-weight ratio dominates the choice of this material. In fact, the advantage of titanium lies in its high reliability and excellent corrosion resistance. It has a proven record in seawater heat exchanger service and a demonstrated excellent reliability even in polluted water. For many reasons it is the technically correct choice of material for marine applications. In this report we review the industrial service history of titanium, particularly in hot saline environments, and demonstrate that it is a viable waste container material, based upon this industrial service history and operating experience. (author)

  3. Surface modification of titanium and titanium alloys by ion implantation.

    Science.gov (United States)

    Rautray, Tapash R; Narayanan, R; Kwon, Tae-Yub; Kim, Kyo-Han

    2010-05-01

    Titanium and titanium alloys are widely used in biomedical devices and components, especially as hard tissue replacements as well as in cardiac and cardiovascular applications, because of their desirable properties, such as relatively low modulus, good fatigue strength, formability, machinability, corrosion resistance, and biocompatibility. However, titanium and its alloys cannot meet all of the clinical requirements. Therefore, to improve the biological, chemical, and mechanical properties, surface modification is often performed. In view of this, the current review casts new light on surface modification of titanium and titanium alloys by ion beam implantation. (c) 2010 Wiley Periodicals, Inc.

  4. Barium aluminides BaxAl5(x=3,3.5,4)

    International Nuclear Information System (INIS)

    Jehle, Michael; Scherer, Harald; Wendorff, Marco; Roehr, Caroline

    2009-01-01

    Three aluminides of the series Ba x Al 5 (x=3,3.5,4) were synthesized from stoichiometric ratios of the elements in Ta crucibles. The crystal structure of the new compound Ba 7 Al 10 was determined using single crystal X-ray data (space group R3-barm, a=604.23(9), c=4879.0(12)pm, Z=3, R1=0.0325). The compound exhibits Al Kagome (3.6.3.6.) nets in which half of the triangles form the basis of trigonal bipyramids Al 5 . The apical Al are thus three-bonded assuming a charge of -2 ( 27 Al-NMR chemical shift δ=660pm), whereas the Al atoms of the basal triangle (i.e. of the Kagome net) are four-bonded and thus of formal charge -1(δ=490ppm). The total charge of the anion is thus exactly compensated by the Ba cations, i.e. the compound can be interpreted as an electron precise Zintl phase, exhibiting a distinct pseudo-band gap at the Fermi level of the calculated tDOS. According to the total formula, the structure displays a combination the stacking sequences of Ba 3 Al 5 and Ba 4 Al 5 , the structures of which have been redetermined with current methods (both hexagonal with space group P6 3 /mmc; Ba 3 Al 5 : a=606.55(7), c=1461.8(2)pm, Z=2, R1=0.0239; Ba 4 Al 5 : a=609.21(7), c=1775.8(3)pm, Z=2, R1=0.0300). These three compounds with slightly different electron counts but similar polyanions allow to compare the bond lengths, the electronic structures and the overall bonding situation in dependence of positive or negative deviation of the electron count in relation to the novel formally electron precise Zintl compound Ba 7 Al 10 . - Al 5 layers of Kagome nets in the new binary electron precise Zintl compound Ba 3.5 Al 5 , also found in Ba 3 Al 5 and Ba 4 Al 5 .

  5. Titanium Implant Osseointegration Problems with Alternate Solutions Using Epoxy/Carbon-Fiber-Reinforced Composite

    OpenAIRE

    Petersen, Richard C.

    2014-01-01

    The aim of the article is to present recent developments in material research with bisphenyl-polymer/carbon-fiber-reinforced composite that have produced highly influential results toward improving upon current titanium bone implant clinical osseointegration success. Titanium is now the standard intra-oral tooth root/bone implant material with biocompatible interface relationships that confer potential osseointegration. Titanium produces a TiO2 oxide surface layer reactively that can provide ...

  6. Titanium and zirconium alloys

    International Nuclear Information System (INIS)

    Pinard Legry, G.

    1994-01-01

    Titanium and zirconium pure and base alloys are protected by an oxide film with anionic vacancies which gives a very good resistance to corrosion in oxidizing medium, in some ph ranges. Results of pitting and crevice corrosion are given for Cl - , Br - , I - ions concentration with temperature and ph dependence, also with oxygenated ions effect. (A.B.). 32 refs., 6 figs., 3 tabs

  7. Effects of plasma parameters and collection region on synthesis of iron and nickel aluminide composite particles during thermal plasma processing

    Science.gov (United States)

    Suresh, K.; Selvarajan, V.

    2010-02-01

    Iron and Nickel aluminide composite particles were synthesized by non-transferred DC plasma spray torch at atmospheric pressure. Irregular shaped ball milled, micron sized powders were fed in to the plasma flame using argon as carrier gas. The particles got molten and vaporized. The vapour condensed on the walls of the reaction chamber and nanoparticles were formed. The molten particles got spheroidized due to surface tension forces. Powders as formed were collected in the plasma reactor at three different sections (Section A, B and C). These powder particles were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The particle size and morphology of the composite particles strongly varied depending on the processing parameters and collection region. The results were discussed.

  8. Monitoring the Degradation Process of Inconel 600 and its Aluminide Coatings under Molten Sulfate Film with Thermal Cycles by Electrochemical Measurements

    International Nuclear Information System (INIS)

    Take, S.; Yoshinaga, S.; Yanagita, M.; Itoi, Y.

    2016-01-01

    With a specially designed electrochemical cell, the changes in impedance behavior for Inconel 600 and aluminide diffusion coatings under molten sulfate film with thermal cycles (from 800 ℃ to 350 ℃) were monitored with electrochemical impedance measurements. It was found that corrosion resistance for both materials increased with lower temperatures. At the same time, the state of molten salt was also monitored successfully by measuring the changes in impedance at high frequency, which generally represents the resistance of molten salt itself. After two thermal cycles, both Inconel 600 and aluminide diffusion coatings showed excellent corrosion resistance. The results from SEM observation and EDS analysis correlated well with the results obtained by electrochemical impedance measurements. It is concluded that electrochemical impedance is very useful for monitoring the corrosion resistance of materials under molten salt film conditions even with thermal cycles.

  9. Antibacterial Titanium Produced Using Selective Laser Melting

    Science.gov (United States)

    Macpherson, Andrew; Li, Xiaopeng; McCormick, Paul; Ren, Ling; Yang, Ke; Sercombe, Timothy B.

    2017-12-01

    Titanium and titanium alloys used in current medical and dental applications do not possess antibacterial properties, and therefore, postoperative infection remains a significant risk. Recently, the addition of silver and copper to conventional biomaterials has been shown to produce a material with good antibacterial properties. In this article, we investigate selective laser melting as a method of producing antibacterial Ti-6Al-4V containing elemental additions of Cu or Ag. The addition of Ag had no effect on the microstructure or strength, but it did result in a 300% increase in the ductility of the alloy. In contrast, the addition of Cu resulted in an increase in strength but in a decrease in ductility, along with a change in the structure of the material. The Cu-containing alloy also showed moderate antibacterial properties and was superior to the Ag-containing alloy.

  10. Titanium fasteners. [for aircraft industry

    Science.gov (United States)

    Phillips, J. L.

    1972-01-01

    Titanium fasteners are used in large quantities throughout the aircraft industry. Most of this usage is in aluminum structure; where titanium structure exists, titanium fasteners are logically used as well. Titanium fasteners offer potential weight savings to the designer at a cost of approximately $30 per pound of weight saved. Proper and least cost usage must take into consideration type of fastener per application, galvanic couples and installation characteristics of protective coatings, cosmetic appearance, paint adhesion, installation forces and methods available and fatigue performance required.

  11. Titanium: light, strong, and white

    Science.gov (United States)

    Woodruff, Laurel; Bedinger, George

    2013-01-01

    Titanium (Ti) is a strong silver-gray metal that is highly resistant to corrosion and is chemically inert. It is as strong as steel but 45 percent lighter, and it is twice as strong as aluminum but only 60 percent heavier. Titanium dioxide (TiO2) has a very high refractive index, which means that it has high light-scattering ability. As a result, TiO2 imparts whiteness, opacity, and brightness to many products. ...Because of the unique physical properties of titanium metal and the whiteness provided by TiO2, titanium is now used widely in modern industrial societies.

  12. Microstructure and hot corrosion behaviors of two Co modified aluminide coatings on a Ni-based superalloy at 700 °C

    Science.gov (United States)

    Fan, Q. X.; Jiang, S. M.; Yu, H. J.; Gong, J.; Sun, C.

    2014-08-01

    Two Co modified aluminide coatings with different Co contents were prepared by pack cementation process and above-the-pack process. The hot corrosion tests of the two coatings were performed in mixed salts of 75 wt.% Na2SO4 + 25 wt.% K2SO4 and 75 wt.% Na2SO4 + 25 wt.% NaCl at 700 °C, with a simple aluminide coating as the reference coating. X-Ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM) with energy dispersive X-ray spectrometer (EDS) were used to characterize the coatings and the corrosion scales. Results indicate that the addition of Co improves the hot corrosion resistance of the simple aluminide coating in the mixed sulfate salts, for the sulfide as well as its eutectic of cobalt are more stable, and possess higher melting points than those of nickel. While in the mixed salt containing chloride, the coating with medium Co content possesses the best corrosion resistance, primarily because the nitrides formed in the deposition process deteriorate the corrosion resistance of the coating with highest Co content.

  13. Towards a new titanium sector: Aerospace

    CSIR Research Space (South Africa)

    Du Preez, W

    2012-10-01

    Full Text Available Sector: Aerospace 4th Biennial Conference Presented by: Dr Willie du Preez Director: Titanium Centre of Competence Date: 9 October 2012 Outline ? Why Titanium? ? The Opportunity for South Africa ? The SA Titanium Industry Strategy ? Primary...747 B777 A380 A350 B787 Materials used in Modern Aircraft: Composites vs Titanium ? CSIR 2012 Slide 6 Source: Engineering News Online, American Institute of Aeronautics & Astronautics Aluminium Composite Steel Titanium Others Titanium...

  14. Formation of Biomimetic Hydroxyapatite Coating on Titanium Plates

    Directory of Open Access Journals (Sweden)

    Ievgen Volodymyrovych PYLYPCHUK

    2014-09-01

    Full Text Available Hydroxyapatite (HA has long been used as a coating material in the implant industry for orthopedic implant applications. HA is the natural inorganic constituent of bone and teeth. By coating titanium (base material of implant engineering because of its lightness and durability with hydroxyapatite, we can provide higher biocompatibility of titanium implants, according to HA ability to form a direct biochemical bond with living tissues. This article reports a biomimetic approach for coating hydroxyapatite with titanium A method of modifying the surface of titanium by organic modifiers (for creating functional groups on the surface, followed by formation "self-assembled" layer of biomimetic hydroxyapatite in simulated body fluid (SBF. FTIR and XPS confirmed the formation of hydroxyapatite coatings on titanium surface. Comparative study of the formation of HA on the surface of titanium plates modified by different functional groups: Ti(≡OH, Ti/(≡Si-OH and Ti/(≡COOH is conducted. It was found that the closest to natural stoichiometric hydroxyapatite Ca/P ratio was obtained on Ti/(≡COOH samples. DOI: http://dx.doi.org/10.5755/j01.ms.20.3.4974

  15. Chemical changes of titanium and titanium dioxide under electron bombardment

    Directory of Open Access Journals (Sweden)

    Romins Brasca

    2007-09-01

    Full Text Available The electron induced effect on the first stages of the titanium (Ti0 oxidation and titanium dioxide (Ti4+ chemical reduction processes has been studied by means of Auger electron spectroscopy. Using factor analysis we found that both processes are characterized by the appearance of an intermediate Ti oxidation state, Ti2O3 (Ti3+.

  16. Plasmonic Titanium Nitride Nanostructures via Nitridation of Nanopatterned Titanium Dioxide

    DEFF Research Database (Denmark)

    Guler, Urcan; Zemlyanov, Dmitry; Kim, Jongbum

    2017-01-01

    Plasmonic titanium nitride nanostructures are obtained via nitridation of titanium dioxide. Nanoparticles acquired a cubic shape with sharper edges following the rock-salt crystalline structure of TiN. Lattice constant of the resulting TiN nanoparticles matched well with the tabulated data. Energy...

  17. Progress in Titanium Metal Powder Injection Molding.

    Science.gov (United States)

    German, Randall M

    2013-08-20

    Metal powder injection molding is a shaping technology that has achieved solid scientific underpinnings. It is from this science base that recent progress has occurred in titanium powder injection molding. Much of the progress awaited development of the required particles with specific characteristics of particle size, particle shape, and purity. The production of titanium components by injection molding is stabilized by a good understanding of how each process variable impacts density and impurity level. As summarized here, recent research has isolated the four critical success factors in titanium metal powder injection molding (Ti-MIM) that must be simultaneously satisfied-density, purity, alloying, and microstructure. The critical role of density and impurities, and the inability to remove impurities with sintering, compels attention to starting Ti-MIM with high quality alloy powders. This article addresses the four critical success factors to rationalize Ti-MIM processing conditions to the requirements for demanding applications in aerospace and medical fields. Based on extensive research, a baseline process is identified and reported here with attention to linking mechanical properties to the four critical success factors.

  18. Progress in Titanium Metal Powder Injection Molding

    Directory of Open Access Journals (Sweden)

    Randall M. German

    2013-08-01

    Full Text Available Metal powder injection molding is a shaping technology that has achieved solid scientific underpinnings. It is from this science base that recent progress has occurred in titanium powder injection molding. Much of the progress awaited development of the required particles with specific characteristics of particle size, particle shape, and purity. The production of titanium components by injection molding is stabilized by a good understanding of how each process variable impacts density and impurity level. As summarized here, recent research has isolated the four critical success factors in titanium metal powder injection molding (Ti-MIM that must be simultaneously satisfied—density, purity, alloying, and microstructure. The critical role of density and impurities, and the inability to remove impurities with sintering, compels attention to starting Ti-MIM with high quality alloy powders. This article addresses the four critical success factors to rationalize Ti-MIM processing conditions to the requirements for demanding applications in aerospace and medical fields. Based on extensive research, a baseline process is identified and reported here with attention to linking mechanical properties to the four critical success factors.

  19. In Situ Characterization Techniques Based on Synchrotron Radiation and Neutrons Applied for the Development of an Engineering Intermetallic Titanium Aluminide Alloy

    Directory of Open Access Journals (Sweden)

    Petra Erdely

    2016-01-01

    Full Text Available Challenging issues concerning energy efficiency and environmental politics require novel approaches to materials design. A recent example with regard to structural materials is the emergence of lightweight intermetallic TiAl alloys. Their excellent high-temperature mechanical properties, low density and high stiffness constitute a profile perfectly suitable for their application as advanced aero-engine turbine blades or as turbocharger turbine wheels in next-generation automotive engines. As the properties of TiAl alloys during processing as well as during service are dependent on the phases occurring, detailed knowledge of their volume fractions and distribution within the microstructure is of paramount importance. Furthermore, the behavior of the individual phases during hot deformation and subsequent heat treatments is of interest to define reliable and cost-effective industrial production processes. In situ high-energy X-ray diffraction methods allow tracing the evolution of phase fractions over a large temperature range. Neutron diffraction unveils information on order-disorder transformations in TiAl alloys. Small-angle scattering experiments offer insights into the materials’ precipitation behavior. This review attempts to shine a light on selected in situ diffraction and scattering techniques and the ways in which they promoted the development of an advanced engineering TiAl alloy.

  20. Ion Implantation Studies of Titanium Metal Surfaces.

    Science.gov (United States)

    1981-01-01

    this peak for both titanium and vanadium . It cannot be associated with an inter-band excitation of any of the oxygen states since it appears in the...Half inch diameter polycrystalline rods of titanium monoxide (TiO), titanium dioxide (TiO 2 and titanium sesquioxide (Ti2 03 ) were obtained from

  1. Hypersensitivity to titanium: a less explored area of research.

    Science.gov (United States)

    Vijayaraghavan, Vasantha; Sabane, Ajay V; Tejas, K

    2012-12-01

    Titanium is considered as an excellent biocompatible metal and it is used in implant dentistry. Literature suggests that Ti can induce clinically relevant hypersensitivity and other immune dysfunctions in certain patients chronically exposed to this reactive metal. At the same time, no standard patch test for Ti has so far been developed, and positive reactions to Ti have therefore only rarely been demonstrated with skin testing. This article reports about the corrosion of dental implants, their significance when hypersensitivity is present, and the literature available till date regarding hypersensitivity of titanium.

  2. SANS investigation on pore growth in self propagating high-temperature-synthesized nickel aluminide: the effect of heat removal

    Energy Technology Data Exchange (ETDEWEB)

    Sen, D. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India) and CEA Saclay, LIONS, DSM/DRECAM/SCM, Bat 125 P 38, 91191 Gif Sur Yvette Cedex (France)]. E-mail: debasis@apsara.barc.ernet.in; Patra, A.K. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Mazumder, S. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Roy, S.K. [Materials Science Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

    2006-11-15

    Small-angle neutron scattering (SANS) has been employed to investigate the effect of heat removal on pore growth during self-propagating high-temperature-synthesis of nickel aluminide. Initially SANS experiments were performed with the double-crystal-based medium resolution (MR-SANS) instrument at the guide tube laboratory, Dhruva reactor, Trombay, India. Subsequently ultra-small-angle neutron scattering (USANS) experiments have been carried out at the USANS facility S18 at the Institute Laue-Langevin (ILL), Grenoble, France. Significant growth in pore size, with respect to green specimen, occurs during synthesis mainly due to thermal migration and molar volume contraction. Rate of heat removal vis-a-vis the velocity of the propagating wave front affects the growth of the pore size in the final product to some extent. Effect of multiple scattering has been utilized to access higher length scale while analyzing scattering data. It has been found that the pore structures vis-a-vis the scattering function can be can be scaled with respect to the average size and the effective radius of gyration of the pores.

  3. SANS investigation on pore growth in self propagating high-temperature-synthesized nickel aluminide: the effect of heat removal

    International Nuclear Information System (INIS)

    Sen, D.; Patra, A.K.; Mazumder, S.; Roy, S.K.

    2006-01-01

    Small-angle neutron scattering (SANS) has been employed to investigate the effect of heat removal on pore growth during self-propagating high-temperature-synthesis of nickel aluminide. Initially SANS experiments were performed with the double-crystal-based medium resolution (MR-SANS) instrument at the guide tube laboratory, Dhruva reactor, Trombay, India. Subsequently ultra-small-angle neutron scattering (USANS) experiments have been carried out at the USANS facility S18 at the Institute Laue-Langevin (ILL), Grenoble, France. Significant growth in pore size, with respect to green specimen, occurs during synthesis mainly due to thermal migration and molar volume contraction. Rate of heat removal vis-a-vis the velocity of the propagating wave front affects the growth of the pore size in the final product to some extent. Effect of multiple scattering has been utilized to access higher length scale while analyzing scattering data. It has been found that the pore structures vis-a-vis the scattering function can be can be scaled with respect to the average size and the effective radius of gyration of the pores

  4. Aluminide slurry coatings for protection of ferritic steel in molten nitrate corrosion for concentrated solar power technology

    Science.gov (United States)

    Audigié, Pauline; Bizien, Nicolas; Baráibar, Ignacio; Rodríguez, Sergio; Pastor, Ana; Hernández, Marta; Agüero, Alina

    2017-06-01

    Molten nitrates can be employed as heat storage fluids in solar concentration power plants. However molten nitrates are corrosive and if operating temperatures are raised to increase efficiencies, the corrosion rates will also increase. High temperature corrosion resistant coatings based on Al have demonstrated excellent results in other sectors such as gas turbines. Aluminide slurry coated and uncoated P92 steel specimens were exposed to the so called Solar Salt (industrial grade), a binary eutectic mixture of 60 % NaNO3 - 40 % KNO3, in air for 2000 hours at 550°C and 580°C in order to analyze their behavior as candidates to be used in future solar concentration power plants employing molten nitrates as heat transfer fluids. Coated ferritic steels constitute a lower cost technology than Ni based alloy. Two different coating morphologies resulting from two heat treatment performed at 700 and 1050°C after slurry application were tested. The coated systems exhibited excellent corrosion resistance at both temperatures, whereas uncoated P92 showed significant mass loss from the beginning of the test. The coatings showed very slow reaction with the molten Solar Salt. In contrast, uncoated P92 developed a stratified, unprotected Fe, Cr oxide with low adherence which shows oscillating Cr content as a function of coating depth. NaFeO2 was also found at the oxide surface as well as within the Fe, Cr oxide.

  5. Inhomogeneity of deformed state during compression testing of titanium implant

    Directory of Open Access Journals (Sweden)

    Loginov Yury

    2017-01-01

    Full Text Available This study examines the inhomogeneity of deformed state during compression testing of porous titanium implant. The theoretical part of the article includes numerical simulation of deformation of a prismatic titanium sample compressed with absolutely rigid plates. The porosity was provided by the circular shape pores with titanium struts between them. To solve the problem by means of the finite element analysis, the boundary conditions were set using the ABAQUS software. The fields of strain, stresses and displacements were determined. Presumable place of fracture coincide with the highest values of strain which are localized in vertical struts. Physical modeling of the implant compression was performed at the second part of the study on the testing machine with video recording. It was shown that in the real process the localization of failure corresponds to the calculated data.

  6. Titanium dioxide, single-walled carbon nanotube composites

    Science.gov (United States)

    Yao, Yuan; Li, Gonghu; Gray, Kimberly; Lueptow, Richard M.

    2015-07-14

    The present invention provides titanium dioxide/single-walled carbon nanotube composites (TiO.sub.2/SWCNTs), articles of manufacture, and methods of making and using such composites. In certain embodiments, the present invention provides membrane filters and ceramic articles that are coated with TiO.sub.2/SWCNT composite material. In other embodiments, the present invention provides methods of using TiO.sub.2/SWCNT composite material to purify a sample, such as a water or air sample.

  7. Titanium in dentistry: historical development, state of the art and future perspectives.

    Science.gov (United States)

    Jorge, Juliana Ribeiro Pala; Barão, Valentim Adelino; Delben, Juliana Aparecida; Faverani, Leonardo Perez; Queiroz, Thallita Pereira; Assunção, Wirley Gonçalves

    2013-06-01

    Titanium is a metallic element known by several attractive characteristics, such as biocompatibility, excellent corrosion resistance and high mechanical resistance. It is widely used in Dentistry, with high success rates, providing a favorable biological response when in contact with live tissues. Therefore, the objective of this study was to describe the different uses of titanium in Dentistry, reviewing its historical development and discoursing about its state of art and future perspective of its utilization. A search in the MEDLINE/PubMed database was performed using the terms 'titanium', 'dentistry' and 'implants'. The title and abstract of articles were read, and after this first screening 20 articles were selected and their full-texts were downloaded. Additional text books and manual search of reference lists within selected articles were included. Correlated literature showed that titanium is the most used metal in Implantology for manufacturing osseointegrated implants and their systems, with a totally consolidated utilization. Moreover, titanium can be also employed in prosthodontics to obtain frameworks. However, problems related to its machining, casting, welding and ceramic application for dental prosthesis are still limiting its use. In Endodontics, titanium has been used in association to nickel for manufacturing rotatory instruments, providing a higher resistance to deformation. However, although the different possibilities of using titanium in modern Dentistry, its use for prostheses frameworks still needs technological improvements in order to surpass its limitations.

  8. Method of activating an article of passive ferrous or non-ferrous metal prior to carburising, nitriding and /or nitrocarburising

    DEFF Research Database (Denmark)

    2011-01-01

    , nitrided or nitrocarburised in shorter time at lower temperature and resulting superior mechanical properties compared with non-activated articles and even articles of stainless steel, nickel alloy, cobalt alloy or titanium based material can be carburised, nitrided or nitrocarburised....

  9. Porcelain veneering of titanium--clinical and technical aspects.

    Science.gov (United States)

    Haag, Per

    2011-01-01

    showed generally unchanged values for color, form, surface and fit. Regarding surfaces, one porcelain fracture was registered (3%). The patient responses were positive and no case of sensitivity was reported after 2 years, but in 3 cases food impaction was reported. The second study is a systematic review of published articles on bond strength between titanium and porcelain. The review made comparisons of bond strength using three-point bending tests between different porcelain bonds to different alloys and to titanium, between different brands of porcelain and titanium, with porcelain following various types of processing of the titanium surface, with different compositions of the porcelain and with different firing conditions. Generally it could be seen that with this type of test (three-point bending) the bond strength between porcelain and titanium was lower than with alloys. It was also seen that there are differences in bond strengths between different brands of porcelain, that processing the titanium surface and composition of the porcelain affected bond strength, and that firing conditions were also important. The third study was performed with the intention of examining the firing accuracy of different types of dental furnaces and to investigate how maintenance and quality control is performed at Swedish dental laboratories. Since titanium porcelain is fired at a temperature which is 200 degrees C below that used for most conventional alloys, there are specific demands on the furnaces used. The optimum firing temperature is judged to be 750 degrees C for porcelain veneering of titanium, according to published studies. In this study the real firing temperature at the holding period of 1 minute was recorded by a thermo-element connected to a digital temperature measurement apparatus. The accuracy of tested furnaces demonstrated a wide variation, and in almost all cases the real temperature was higher than the temperature indicated by the furnace display; in some

  10. Microstructure and hot corrosion behaviors of two Co modified aluminide coatings on a Ni-based superalloy at 700 °C

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Q.X., E-mail: qxfan@imr.ac.cn; Jiang, S.M., E-mail: smjiang@imr.ac.cn; Yu, H.J.; Gong, J.; Sun, C.

    2014-08-30

    Highlights: • Microstructures of two Co modified NiAl coatings have been studied. • The addition of Co improves the corrosion resistance in sulfate salts at 700 °C. • For the sulfide and its eutectic of Co are more stable than those of Ni. • In chloride salts coating with medium Co content has best corrosion resistance. - Abstract: Two Co modified aluminide coatings with different Co contents were prepared by pack cementation process and above-the-pack process. The hot corrosion tests of the two coatings were performed in mixed salts of 75 wt.% Na{sub 2}SO{sub 4} + 25 wt.% K{sub 2}SO{sub 4} and 75 wt.% Na{sub 2}SO{sub 4} + 25 wt.% NaCl at 700 °C, with a simple aluminide coating as the reference coating. X-Ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM) with energy dispersive X-ray spectrometer (EDS) were used to characterize the coatings and the corrosion scales. Results indicate that the addition of Co improves the hot corrosion resistance of the simple aluminide coating in the mixed sulfate salts, for the sulfide as well as its eutectic of cobalt are more stable, and possess higher melting points than those of nickel. While in the mixed salt containing chloride, the coating with medium Co content possesses the best corrosion resistance, primarily because the nitrides formed in the deposition process deteriorate the corrosion resistance of the coating with highest Co content.

  11. Development of ion-plated aluminide diffusion coatings for thermal cyclic oxidation and hot corrosion protection of a nickel-based superalloy and a stainless steel

    Science.gov (United States)

    Elsawy, Abdel Raouf

    This project was carried out at the University of Toronto and Cametoid Ltd of Whitby, Ontario. Ohno continuous casting; a novel net shape casting technique, was used to generate, Al-Y, Al-Ce, Al-La, and Al-Si-Y, in form of 1.6 to 1.7 mm diameter alloy wires. These alloy wires exhibited suitable properties for use as feed materials to an Ion Vapor Deposition facility. The deposition parameters were optimized to provide coatings with a compact and cohesive columnar structure with reduced porosity and diffusion barriers that were essential to ensure the success of the diffusion process in the subsequent stage. Solid-state diffusion heat treatment processes were developed in order to form the stable aluminide phases, AlNi and FeAl, on IN738 and S310 substrates, respectively. Experiments simulating the coating service conditions and environments encountered during the prospective aerospace and fuel cell applications were conducted to evaluate the performance of each aluminide coating developed during this study. Thermal cyclic oxidation and molten sulfate corrosion studies were performed on coated IN738 pins at 1050°C and 900°C, respectively, simulating the service environment of turbine engine blades and other hot section components. Molten carbonate corrosion behavior was investigated for coated S310 coupons that were immersed in, or covered with a thin film of molten carbonate, at 650°C, in air plus 30%CO2, to simulate the operating conditions of the cathode-side separator plates of molten carbonate fuel cells. The behavior of the reactive elements, yttrium, cerium, lanthanum, and silicon in enhancing the adhesion of the protective aluminum oxide scale was determined by weight variation experiments, structural examination and compositional analysis. The influence of the base material elements, nickel, chromium, and iron, on the formation of protective oxides was investigated. All coatings were found to provide significant improvement for thermal cyclic oxidation

  12. Low cost titanium--myth or reality

    Energy Technology Data Exchange (ETDEWEB)

    Turner, Paul C.; Hartman, Alan D.; Hansen, Jeffrey S.; Gerdemann, Stephen J.

    2001-01-01

    In 1998, approximately 57,000 tons of titanium metal was consumed in the form of mill products (1). Only about 5% of the 4 million tons of titanium minerals consumed each year is used to produce titanium metal, with the remainder primarily used to produce titanium dioxide pigment. Titanium metal production is primarily based on the direct chlorination of rutile to produce titanium tetrachloride, which is then reduced to metal using the Kroll magnesium reduction process. The use of titanium is tied to its high strength-to-weight ratio and corrosion resistance. Aerospace is the largest application for titanium, and titanium cost has prevented its use in non-aerospace applications including the automotive and heavy vehicle industries.

  13. Surface engineering by thermal spraying nanocrystalline coatings: X-ray and TEM characterisation of As-deposited iron aluminide structure

    Science.gov (United States)

    Ji, G.; Morniroli, J. P.; Tidu, A.; Coddet, C.; Grosdidier, T.

    2002-07-01

    Iron Aluminide coatings were produced by thermal spraying atomized (microcrystalline) and milled (nanocrystalline) powders using the High Velocity Oxy-Fuel (HVOF) and the Atmospheric Plasma Spraying (APS) techniques. The as-sprayed coatings were investigated by X-ray diffraction. In particular, X-ray line shape broadening analysis was used to determine the size of the coherently diffracting domains and the internal microstrains. Significant peak broadening was observed whatever the thermal spraying technique and the starting feedstock powder. This surprising result is discussed, at the light of SEM and TEM observations, by considering chemical composition heterogeneities and the presence of structural defects in the coatings. Des revêtements d'aluminure de fer ont été projetés à l'aide des techniques HVOF et APS en utilisant comme précurseur de la poudre atomisée à structure microcristalline ou de la poudre à structure nanocristalline obtenue par broyage mécanique. La microstructure des revêtements a été analysée par diffraction des rayons X en utilisant, en particulier, des analyses de profils de raies. Des élargissements importants des raies de diffraction ont été mesurés quelque soit la technique de projection utilisée ou la nature des précurseurs. Ces résultats surprenants sont discutés, à l'aide d'observations effectuées en MEB et MET, en prenant en compte les gradients chimiques et la présence de défauts structuraux observés dans les revêtements.

  14. Atomic hydrogen and diatomic titanium-monoxide molecular spectroscopy in laser-induced plasma

    Science.gov (United States)

    Parigger, Christian G.; Woods, Alexander C.

    2017-03-01

    This article gives a brief review of experimental studies of hydrogen Balmer series emission spectra. Ongoing research aims to evaluate early plasma evolution following optical breakdown in laboratory air. Of interest is as well laser ablation of metallic titanium and characterization of plasma evolution. Emission of titanium monoxide is discussed together with modeling of diatomic spectra to infer temperature. The behavior of titanium particles in plasma draws research interests ranging from the modeling of stellar atmospheres to the enhancement of thin film production via pulsed laser deposition.

  15. Comparison of Titanium vs. Polycel Total Ossicular Replacement Prosthesis

    Directory of Open Access Journals (Sweden)

    Mohammad Faramarzi

    2016-01-01

    Full Text Available Introduction: Even though modern technology progresses so rapidly, annals of otology are replete with so many challenging article, which often compare various types of prosthesis. Since there has not been a prospective randomized clinical trial study which compares the hearing result of total ossicular replacement prosthesis made of Titanium with omega connector and Polycel in the literature, we decided to perform a study encompassing this issue.   Materials and Methods: 105 patients, who were in the 2nd stage of their operation and who needed total ossicular replacement prosthesis, were included in this prospective single blind randomized clinical trial study. Patients were classified in two groups: titanium Kurz (TTP™ -Vario system, Kurz GmbH, Dusslingen, Germany with omega connector and Polycel (Sheehy Plastipore Polycel, Medtronic Xomed Inc. The duration of the follow up was 6-12 months. In order to evaluate hearing results, pure tone audiometric in 0.5, 1, 2, and 4 kHz were checked. In addition, speech reception threshold was recorded. A successful surgery was defined as having a postoperative air–bone gap within 20 dB.   Results: We accomplished successful hearing in 64.4% of patients with titanium and 65% of patients with a Polycel prosthesis.Improvement in speech reception threshold was 11.5 dB in the titanium group and 13 dB in the Polycel group. In other words, there was no significant difference between the two groups. In addition, air-bone gap improvement after ossiculoplasty was 11.2 dB in the patients with a titanium prosthesis and 12.4 dB in the Polycel group. In fact, the difference was not significant.   Conclusion: We found that both the titanium and the Polycel prosthesis improve speech reception threshold and air-bone gap closure in a similar manner.

  16. Plasmonic titanium nitride nanostructures for perfect absorbers

    DEFF Research Database (Denmark)

    Guler, Urcan; Li, Wen-Wei; Kinsey, Nathaniel

    2013-01-01

    We propose a metamaterial based perfect absorber in the visible region, and investigate the performance of titanium nitride as an alternative plasmonic material. Numerical and experimental results reveal that titanium nitride performs better than gold as a plasmonic absorbing material...

  17. Fiber Lasers Application for Welding of Titanium Alloys With 16 mm Thickness

    Science.gov (United States)

    Evtihiev, N. N.; Grezev, N. V.; Markushov, Y. V.; Murzakov, M. A.

    2016-09-01

    This article illustrates the use of fiber laser welding of a titanium alloy with 16 mm thickness. The basic advantages of the laser welding process over the traditional methods of arc welding of titanium are demonstrated. Destructive testing of welds was performed to confirm the quality of the welding. The results of the static tensile tests, static bending and toughness at room temperature are presented. All tests confirmed the high quality of the welded joint.

  18. The extraction of vanadium pentoxide from waste of titanium tetrachloride by various methods

    Directory of Open Access Journals (Sweden)

    Инна Михайловна Гунько

    2015-04-01

    Full Text Available In article the recovery possibility of vanadium pentoxide from wastes, formed as a result of purification from impurities of technical titanium tetrachloride is researched. The purification from impurities is realized by different methods – pulp of lower titanium chlorides, hydrocarbonic reducer and cascade-rectifying purification. Usage of these purification methods leads to formation of anthropogenic wastes. The researches is shown that processing of these wastes is reasonable for the purpose of vanadium pentoxide extraction

  19. Printing of Titanium implant prototype

    International Nuclear Information System (INIS)

    Wiria, Florencia Edith; Shyan, John Yong Ming; Lim, Poon Nian; Wen, Francis Goh Chung; Yeo, Jin Fei; Cao, Tong

    2010-01-01

    Dental implant plays an important role as a conduit of force and stress to flow from the tooth to the related bone. In the load sharing between an implant and its related bone, the amount of stress carried by each of them directly related to their stiffness or modulus. Hence, it is a crucial issue for the implant to have matching mechanical properties, in particular modulus, between the implant and its related bone. Titanium is a metallic material that has good biocompatibility and corrosion resistance. Whilst the modulus of the bulk material is still higher than that of bone, it is the lowest among all other commonly used metallic implant materials, such as stainless steel or cobalt alloy. Hence it is potential to further reduce the modulus of pure Titanium by engineering its processing method to obtain porous structure. In this project, porous Titanium implant prototype is fabricated using 3-dimensional printing. This technique allows the flexibility of design customization, which is beneficial for implant fabrication as tailoring of implant size and shape helps to ensure the implant would fit nicely to the patient. The fabricated Titanium prototype had a modulus of 4.8-13.2 GPa, which is in the range of natural bone modulus. The compressive strength achieved was between 167 to 455 MPa. Subsequent cell culture study indicated that the porous Titanium prototype had good biocompatibility and is suitable for bone cell attachment and proliferation.

  20. Article and process for producing an article

    Science.gov (United States)

    Lacy, Benjamin Paul; Jacala, Ariel Caesar Prepena; Kottilingam, Srikanth Chandrudu; Schick, David Edward

    2017-10-24

    An article and a process of producing an article are provided. The article includes a base material, a cooling feature arrangement positioned on the base material, the cooling feature arrangement including an additive-structured material, and a cover material. The cooling feature arrangement is between the base material and the cover material. The process of producing the article includes manufacturing a cooling feature arrangement by an additive manufacturing technique, and then positioning the cooling feature arrangement between a base material and a cover material.

  1. Anodic growth of titanium dioxide nanostructures

    DEFF Research Database (Denmark)

    2010-01-01

    Disclosed is a method of producing nanostructures of titanium dioxide (TiO 2 ) by anodisation of titanium (Ti) in an electrochemical cell, comprising the steps of: immersing a non-conducting substrate coated with a layer of titanium, defined as the anode, in an electrolyte solution...... an electrical contact to the layer of titanium on the anode, where the electrical contact is made in the electrolyte solution...

  2. Uranium fluorides analysis. Titanium spectrophotometric determination

    International Nuclear Information System (INIS)

    Anon.

    Titanium determination in uranium hexafluoride in the range 0.7 to 100 microgrammes after transformation of uranium fluoride in sulfate. Titanium is separated by extraction with N-benzoylphenylhydroxylamine, reextracted by hydrochloric-hydrofluoric acid. The complex titanium-N-benzoylphenylhydroxylamine is extracted by chloroform. Spectrophotometric determination at 400 nm [fr

  3. 21 CFR 73.1575 - Titanium dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.1575 Section 73.1575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1575 Titanium dioxide. (a) Identity and specifications. (1) The color additive titanium dioxide shall conform in identity and specifications to the requirements...

  4. 40 CFR 180.1195 - Titanium dioxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Titanium dioxide. 180.1195 Section 180.1195 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... Titanium dioxide. Titanium dioxide is exempted from the requirement of a tolerance for residues in or on...

  5. 21 CFR 73.2575 - Titanium dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.2575 Section 73.2575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2575 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide shall conform in identity and specifications to the requirements...

  6. 21 CFR 73.575 - Titanium dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.575 Section 73.575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.575 Titanium dioxide. (a) Identity. (1) The color additive titanium dioxide is synthetically prepared TiO2, free from admixture with other substances. (2) Color...

  7. 21 CFR 73.3126 - Titanium dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.3126 Section 73.3126 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3126 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide (CAS Reg. No. 13463-67-7), Color Index No. 77891, shall...

  8. Adaptive mesh refinement in titanium

    Energy Technology Data Exchange (ETDEWEB)

    Colella, Phillip; Wen, Tong

    2005-01-21

    In this paper, we evaluate Titanium's usability as a high-level parallel programming language through a case study, where we implement a subset of Chombo's functionality in Titanium. Chombo is a software package applying the Adaptive Mesh Refinement methodology to numerical Partial Differential Equations at the production level. In Chombo, the library approach is used to parallel programming (C++ and Fortran, with MPI), whereas Titanium is a Java dialect designed for high-performance scientific computing. The performance of our implementation is studied and compared with that of Chombo in solving Poisson's equation based on two grid configurations from a real application. Also provided are the counts of lines of code from both sides.

  9. Article and method of forming an article

    Science.gov (United States)

    Lacy, Benjamin Paul; Kottilingam, Srikanth Chandrudu; Dutta, Sandip; Schick, David Edward

    2017-12-26

    Provided are an article and a method of forming an article. The method includes providing a metallic powder, heating the metallic powder to a temperature sufficient to joint at least a portion of the metallic powder to form an initial layer, sequentially forming additional layers in a build direction by providing a distributed layer of the metallic powder over the initial layer and heating the distributed layer of the metallic powder, repeating the steps of sequentially forming the additional layers in the build direction to form a portion of the article having a hollow space formed in the build direction, and forming an overhang feature extending into the hollow space. The article includes an article formed by the method described herein.

  10. Solution and precipitation hardening of two-phase gamma titanium alloy; Mischkristall- und Ausscheidungshaertung zweiphasiger Gamma-Titanaluminidlegierungen

    Energy Technology Data Exchange (ETDEWEB)

    Christoph, U. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Werkstofforschung

    1997-12-31

    The present study on solution and precipitation hardening of two-phase gamma titanium aluminides was directed towards improved creep resistance. Alloys were systematically doped with carbon up to 0.37 atomic percent. Solid solutions and precipitates of carbon were formed by different thermal treatments. The hardening obtained as a result of the different precipitate conditions was measured by deformation experiments between 293 and 973 K. An increase of yield stress of up to 300 MPa was observed for finely distributed perovskite precipitates. This increase of yield stress was maintained up to 973 K and was shown to be dominantly athermal in character from activation parameter measurements. Electron microscopic investigations confirmed the athermal nature of the perovskite precipitates to dislocation motion. The precipitates thus act as barriers to dislocation glide over a wide temperature range and can therefore increase the creep resistance at the anticipated operation temperature of 973 K. In addition to studying the mechanism of precipitation hardening, the pinning of dislocations by the formation of impurity atmospheres has also been investigated. This phenomenon is effective at intermediate temperatures of around 550 K and is thought to be caused by very mobile elements such as iron and boron. These elements are present in all alloys of technical relevance. (orig.) 158 refs.

  11. Lactobacillusassisted synthesis of titanium nanoparticles

    Directory of Open Access Journals (Sweden)

    Jha Anal

    2007-01-01

    Full Text Available AbstractAn eco-friendlylactobacillussp. (microbe assisted synthesis of titanium nanoparticles is reported. The synthesis is performed at room temperature. X-ray and transmission electron microscopy analyses are performed to ascertain the formation of Ti nanoparticles. Individual nanoparticles as well as a number of aggregates almost spherical in shape having a size of 40–60 nm are found.

  12. Publishing International Counseling Articles

    Science.gov (United States)

    Hohenshil, Thomas H.; Amundson, Norman E.

    2011-01-01

    This article begins with a rationale for including international articles in the "Journal of Counseling & Development." Then, 2 general categories of international articles are described. First are articles that provide a general overview of counseling in a particular country. The 2nd category is more general and might involve international…

  13. Is zirconia a viable alternative to titanium for oral implant? A critical review.

    Science.gov (United States)

    Sivaraman, Karthik; Chopra, Aditi; Narayan, Aparna I; Balakrishnan, Dhanasekar

    2017-08-17

    Titanium based implant systems, though considered as the gold standard for rehabilitation of edentulous spaces, have been criticized for many inherent flaws. The onset of hypersensitivity reactions, biocompatibility issues, and an unaesthetic gray hue have raised demands for more aesthetic and tissue compatible material for implant fabrication. Zirconia is emerging as a promising alternative to conventional Titanium based implant systems for oral rehabilitation with superior biological, aesthetics, mechanical and optical properties. This review aims to critically analyze and review the credibility of Zirconia implants as an alternative to Titanium for prosthetic rehabilitation. The literature search for articles written in the English language in PubMed and Cochrane Library database from 1990 till December 2016. The following search terms were utilized for data search: "zirconia implants" NOT "abutment", "zirconia implants" AND "titanium implants" AND "osseointegration", "zirconia implants" AND compatibility. The number of potential relevant articles selected were 47. All the human in vivo clinical, in vitro, animals' studies were included and discussed under the following subheadings: Chemical composition, structure and phases; Physical and mechanical properties; Aesthetic and optical properties; Osseointegration and biocompatibility; Surface modifications; Peri-implant tissue compatibility, inflammation and soft tissue healing, and long-term prognosis. Zirconia implants are a promising alternative to titanium with a superior soft-tissue response, biocompatibility, and aesthetics with comparable osseointegration. However, further long-term longitudinal and comparative clinical trials are required to validate zirconia as a viable alternative to the titanium implant. Copyright © 2017 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  14. Article and method for making an article

    Energy Technology Data Exchange (ETDEWEB)

    Lacy, Benjamin Paul; Schick, David Edward; Kottilingam, Srikanth Chandrudu

    2018-04-03

    An article and a method for making shaped cooling holes in an article are provided. The method includes the steps of depositing a metal alloy powder to form an initial layer including at least one aperture, melting the metal alloy powder with a focused energy source to transform the powder layer to a sheet of metal alloy, sequentially depositing an additional layer of the metal alloy powder to form a layer including at least one aperture corresponding to the at least one aperture in the initial layer, melting the additional layer of the metal alloy powder with the focused energy source to increase the sheet thickness, and repeating the steps of sequentially depositing and melting the additional layers of metal alloy powder until a structure including at least one aperture having a predetermined profile is obtained. The structure is attached to a substrate to make the article.

  15. Article and method for making an article

    Energy Technology Data Exchange (ETDEWEB)

    Lacy, Benjamin Paul; Schick, David Edward; Kottilingam, Srikanth Chandrudu

    2018-04-03

    An article and a method for making shaped cooling holes in an article are provided. The method includes the steps of providing a metal alloy powder; forming an initial layer with the metal alloy powder, the initial layer having a preselected thickness and a preselected shape, the preselected shape including at least one aperture; sequentially forming an additional layer over the initial layer with the metal alloy powder, the additional layer having a second preselected thickness and a second preselected shape, the second preselected shape including at least one aperture corresponding to the at least one aperture in the initial layer; and joining the additional layer to the initial layer, forming a structure having a predetermined thickness, a predetermined shape, and at least one aperture having a predetermined profile. The structure is attached to a substrate to make the article.

  16. High-temperature ordered intermetallic alloys VI: Part 2. Materials Research Society symposium proceedings Volume 364

    International Nuclear Information System (INIS)

    Horton, J.; Baker, I.; Hanada, Shuji; Noebe, R.D.; Schwartz, D.S.

    1995-01-01

    This book is divided into the following sections: Ni 3 Al -- dislocations and atomic structure; titanium aluminides -- processing; Ni 3 Al -- mechanical properties and processing; silicides; titanium aluminides and exotics; environmental effects and surface treatments; trialuminides and Ti 2 AlNb; oxidation; and niobium aluminides and Laves phases. Separate abstracts were prepared for 116 papers

  17. Antimicrobial titanium/silver PVD coatings on titanium

    Directory of Open Access Journals (Sweden)

    Thull Roger

    2006-03-01

    Full Text Available Abstract Background Biofilm formation and deep infection of endoprostheses is a recurrent complication in implant surgery. Post-operative infections may be overcome by adjusting antimicrobial properties of the implant surface prior to implantation. In this work we described the development of an antimicrobial titanium/silver hard coating via the physical vapor deposition (PVD process. Methods Coatings with a thickness of approximately 2 μm were deposited on titanium surfaces by simultaneous vaporisation of both metals in an inert argon atmosphere with a silver content of approximately 0.7 – 9% as indicated by energy dispersive X-ray analysis. On these surfaces microorganisms and eukaryotic culture cells were grown. Results The coatings released sufficient silver ions (0.5–2.3 ppb when immersed in PBS and showed significant antimicrobial potency against Staphylococcus epidermis and Klebsiella pneumoniae strains. At the same time, no cytotoxic effects of the coatings on osteoblast and epithelial cells were found. Conclusion Due to similar mechanical performance when compared to pure titanium, the TiAg coatings should be suitable to provide antimicrobial activity on load-bearing implant surfaces.

  18. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2017-11-24

    . Self-medication may be one of the major consequences of drug advertising. Methodology: This review article was conducted through reviewing 100 articles and 12 books, derived from valid libraries and electronic sources.

  19. [Reading research articles].

    Science.gov (United States)

    van der Graaf, Yolanda; Zaat, Joost

    2015-01-01

    Keeping up with the latest developments is not easy, but neither is reading articles on research. There are too many medical journals that contain information that is irrelevant to clinical practice. From this mass of articles you have to decide which are important for your own clinical practice and which are not. Most articles naturally fall into the latter category as spectacular findings with important consequences for medical practice do not occur every week. The most important thing in a research article is the research question. If you begin with this, then you can put aside much scientific literature. The methodology section is essential; reading this can save you a lot of time. In this article we take you step-by-step through the process of reading research articles. The articles in our Methodology series can be used as background information. These articles have been combined in a tablet app, which is available via www.ntvg.nl/methodologie.

  20. [Micro-porous titanium implants in orthognathic facial recontouring].

    Science.gov (United States)

    Charrier, Jean-Baptiste; Moreau, Nathan

    2016-09-01

    Facial symmetry has always been a longstanding objective of orthognathic surgery. Patients that present significant facial asymmetry desire functional dental occlusion but also seek to enhance their facial esthetics. In that regard, different surgical techniques have been proposed to enhance facial recontouring. Through a clinical case report and a literature review, this article explores the use of allopastic microporous titanium implants in volumetric corrections of the face. There is a current lack of evidence regarding the use of microporous titanium implants in volumetric corrections of the face, most papers reporting their use in post-traumatic or post-surgical cranio-facial defects repair. Pros and cons of such implants are discussed in association with the usefulness of this surgical technique in daily orthognathic surgical practice. © EDP Sciences, SFODF, 2016.

  1. Titanium: the innovators metal. Historical case studies tracing titanium process and product innovation [Conference paper

    CSIR Research Space (South Africa)

    Oosthuizen, SJ

    2010-10-01

    Full Text Available at the development of a proprietary low cost titanium metal production process, and the continued development and commercialisation of technologies to compete cost effectively in international titanium markets4. Considering that the national strategy... of primary importance in the establishment of markets for titanium? c) Can it be reasoned that South African strategy for titanium beneficiation should include efforts to develop and support innovation and entrepreneurship in this field? Findings...

  2. Failure mechanisms of platinum aluminide bond coat/electron beam-physical vapor deposited thermal barrier coatings

    Science.gov (United States)

    Vaidyanathan, Krishnakumar

    Thermal barrier coatings (TBCs) allow operation of structural components, such as turbine blades and vanes in industrial and aircraft gas engines, at temperatures close to the substrate melting temperatures. They consist of four different layers; a high strength creep-resistant nickel-based superalloy substrate, an oxidation resistant bond coat (BC), a low thermal conductivity ceramic topcoat and a thermally grown oxide (TGO), that is predominantly alpha-Al 2O3, that forms between the BC and the TBC. Compressive stresses (3--5 GPa) that are generated in the thin TGO (0.25--8 mum) due to the mismatch in thermal coefficient of expansion between the TGO and BC play a critical role in the failure of these coatings. In this study, the failure mechanisms of a commercial yttria-stabilized zirconia (7YSZ) electron beam-physical vapor deposited (EB-PVD) coating on platinum aluminide (beta-(Ni,Pt)Al) bond coat have been identified. Two distinct mechanisms have been found responsible for the observed damage initiation and progression at the TGO/bond coat interface. The first mechanism leads to localized debonding at TGO/bond coat interface due to increased out-of-plane tensile stress, along bond coat features that manifest themselves as ridges. The second mechanism causes cavity formation at the TGO/bond coat interface, driven by cyclic plasticity of the bond coat. It has been found that the debonding at the TGO/bond coat interface due to the first mechanism is solely life determining. The final failure occurs by crack extension along either the TGO/bond coat interface or the TGO/YSZ interface or a combination of both, leading to large scale buckling. Based on these mechanisms, it is demonstrated that the bond coat grain size and the aspect ratio of the ridges have a profound influence on spallation lives of the coating. The removal of these ridges by fine polishing prior to TBC deposition led to a four-fold improvement in life. The failure mechanism identified for the

  3. Titanium - ceramic restoration: How to improve the binding between titanium and ceramic

    Directory of Open Access Journals (Sweden)

    Harry Laksono

    2011-03-01

    Full Text Available Background: Titanium alloys has been used as an alternative to nickel-chromium alloys for metal-ceramic restorations because of its good biocompatibility and mechanical properties. This indicated that it was possible to design coping according to standards established for metal-ceramics. However, titanium is chemically reacting strongly with gaseous elements which causes problems when ceramics are fused to titanium. Purpose: To provide information about improving the bonding between titanium and ceramic. Review: Titanium has two crystal modifications, the close-packed hexagonal (α structure, up to 880° C, and above this temperature the bodycentered cubic (β structure. The principal problems is the extensive dissolution of oxygen resulting in thick, oxygen-rich titanium layers called α-case that harms the bonding of ceramic to titanium and the great mismatch in the coefficient of thermal expansion of conventional ultra-low fusing ceramic. Methods have been developed for fusing ceramic to titanium like processing methods, the used of ultra-low fusing titanium ceramic, bonding agent, and protocol for ceramic bonding to titanium. Conclusion: Titanium and titanium alloys, based on their physical and chemical properties suitable for titanium-ceramic restorations, but careful selection of processing methods, ceramic materials, laboratory skill and strict protocol for ceramic bonding to titanium are necessary to improve the bonding between titanium and ceramic.Latar Belakang: Logam campur titanium telah dipakai sebagai salah satu bahan alternatif untuk logam nikel-krom pada pembuatan restorasi keramik taut logam karena mempunyai biokompatibilitas dan sifat mekanik yang baik. Hal ini menunjukkan bahwa logam titanium dapat dipakai untuk pembuatan koping logam berdasarkan standar yang dipakai untuk pembuatan restorasi keramik taut logam. Meskipun, secara kimiawi logam titanium bereaksi dengan elemen-elemen gas yang menyebabkan masalah pada perlekatan

  4. Selective recovery of titanium dioxide from low grade sources

    CSIR Research Space (South Africa)

    Van Vuuren, DS

    2006-09-01

    Full Text Available There are a number of readily available, large reserves of titanium dioxide bearing minerals from which the titanium dioxide cannot currently be economically recovered via current commercial recovery processes due to: The grade of titanium dioxide...

  5. Clinical bending of nickel titanium wires

    OpenAIRE

    Stephen Chain; Priyank Seth; Namrata Rastogi; Kenneth Tan; Mayank Gupta; Richa Singh

    2015-01-01

    Since the evolution and the involvement of Nickel Titanium wires in the field of Orthodontics. The treatment plan has evolved with the use of low force Nickel Titanium wires. Because of their high springback, low stiffness, they are the key initial wires in leveling and alignment but have poor formability. Since poor formability limits its ability to create variable arch forms thus; limits the form of treatment. We have devised a method to bend the Nickel Titanium wires to help in our invento...

  6. Production of titanium from ilmenite: a review

    Energy Technology Data Exchange (ETDEWEB)

    Kohli, R.

    1981-12-01

    The general principles for beneficiation of titanium ores are reviewed and the specific processes used in individual units in various countries are discussed. This is followed by a critical evaluation of various current and potential reduction methods for the production of titanium metal from the processed concentrates. Finally, the report outlines a research program for the development of a commercially viable alternative method for the production of titanium metal.

  7. Titanium metal obtention by fused salts electrolysis

    International Nuclear Information System (INIS)

    Perillo, P.M.; Ares, Osvaldo; Botbol, Jose.

    1989-01-01

    Potassium fluorotitanate dissolved in fused sodium chloride or potassium chloride may be electrolyzed under an inert gas atmosphere. Solid electrolysis products are formed on the cathode which contains titanium metal, sodium chloride, lower fluorotitanates and small quantities of alkali metal fluorotitanate. The extraction of titanium from the electrolysis products may be carried out by aqueous leaching (removal of chloride salts of alkali metals and a certain amount of fluorotitanates). Titanium metal obtained is relatively pure. (Author)

  8. Machinability evaluation of titanium alloys.

    Science.gov (United States)

    Kikuchi, Masafumi; Okuno, Osamu

    2004-03-01

    In the present study, the machinability of titanium, Ti-6Al-4V, Ti-6A1-7Nb, and free-cutting brass was evaluated using a milling machine. The metals were slotted with square end mills under four cutting conditions. The cutting force and the rotational speed of the spindle were measured. The cutting forces for Ti-6Al-4V and Ti-6Al-7Nb were higher and that for brass was lower than that for titanium. The rotational speed of the spindle was barely affected by cutting. The cross sections of the Ti-6Al-4V and Ti-6Al-7Nb chips were more clearly serrated than those of titanium, which is an indication of difficult-to-cut metals. There was no marked difference in the surface roughness of the cut surfaces among the metals. Cutting force and the appearance of the metal chips were found to be useful as indices of machinability and will aid in the development of new alloys for dental CAD/CAM and the selection of suitable machining conditions.

  9. Cranioplasty with individual titanium implants

    Science.gov (United States)

    Mishinov, S.; Stupak, V.; Sadovoy, M.; Mamonova, E.; Koporushko, N.; Larkin, V.; Novokshonov, A.; Dolzhenko, D.; Panchenko, A.; Desyatykh, I.; Krasovsky, I.

    2017-09-01

    Cranioplasty is the second procedure in the history of neurosurgery after trepanation, and it is still relevant despite the development of civilization and progress in medicine. Each cranioplasty operation is unique because there are no two patients with identical defects of the skull bones. The development of Direct Metal Laser Sintering (DMLS) technique opened up the possibility of direct implant printing of titanium, a biocompatible metal used in medicine. This eliminates the need for producing any intermediate products to create the desired implant. We have produced 8 patient-specific titanium implants using this technique for patients who underwent different decompressive cranioectomies associated with bone tumors. Follow-up duration ranged from 6 to 12 months. We observed no implant-related reactions or complications. In all cases of reconstructive neurosurgery we achieved good clinical and aesthetic results. The analysis of the literature and our own experience in three-dimensional modeling, prototyping, and printing suggests that direct laser sintering of titanium is the optimal method to produce biocompatible surgical implants.

  10. 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.

  11. Appcelerator Titanium patterns and best practices

    CERN Document Server

    Pollentine, Boydlee

    2013-01-01

    The book takes a step-by-step approach to help you understand CommonJS and Titanium architecture patterns, with easy to follow samples and plenty of in-depth explanations If you're an existing Titanium developer or perhaps a new developer looking to start off your Titanium applications "the right way", then this book is for you. With easy to follow examples and a full step-by-step account of architecting a sample application using CommonJS and MVC, along with chapters on new features such as ACS, you'll be implementing enterprise grade Titanium solutions in no time. You should have some JavaSc

  12. Titanium Matrix Composite Pressure Vessel, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — For over 15 years, FMW Composite Systems has developed Metal Matrix Composite manufacturing methodologies for fabricating silicon-carbide-fiber-reinforced titanium...

  13. Titanium Matrix Composite Pressure Vessel Project

    Data.gov (United States)

    National Aeronautics and Space Administration — For over 15 years, FMW Composite Systems has developed Metal Matrix Composite manufacturing methodologies for fabricating silicon-carbide-fiber-reinforced titanium...

  14. [Titanium or steel as osteosynthesis material : Systematic literature search for clinical evidence].

    Science.gov (United States)

    Joeris, Alexander; Goldhahn, Sabine; Rometsch, Elke; Höntzsch, Dankward

    2017-02-01

    The selection of the appropriate implant material, stainless steel or titanium, is still the decision of the surgeon and/or the affiliated institution. Additionally, remarkable international differences can be found between the different markets, which cannot really be explained. A systematic literature search was performed to verify whether there is clinical evidence for the preference of one material over the other. The systematic literature search was performed utilizing the internet databases PubMed, Cochrane and Web of Science. Comparative studies were included that reported on adult patients with osteosynthesis of extremities after trauma using either stainless steel or titanium implants. Information was extracted about infection rates, incidence of clinically relevant allergies, problems with implant removal and other complications. A total of 18 publications were identified to be eligible and 2 referenced articles were added. In summary, there is insufficient clinical evidence that the use of titanium or steel implants has a positive or negative effect on fracture healing, shows different rates of allergies, different rates of infections or mechanical failure. No supporting evidence could be identified for the difficulties with removal of titanium implants reported by surgeons. This systematic literature search did not provide any clinical evidence for material-related differences between titanium or stainless steel implants for fracture fixation. Based on the current clinical evidence both titanium and steel implants can be considered to be of equal value. The reported difficulties with implant removal are not reflected in the published literature.

  15. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2017-08-08

    Aug 8, 2017 ... program codes) assembly of program systems of applied appointment are presented in article. Author Correspondence ... automated), testing of the created system, its documenting, quality assessment, estimation of cost. Assembly is carried out in the ... JAVA environments. In article (with specification as far ...

  16. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2017-11-10

    Nov 10, 2017 ... There are numerous articles composed by researchers on the selection of a model from a repository of models in machine learning techniques. The majority of the articles have distinctive experimental strategies and a diverse range of study from others. The main measures utilized for accuracy evaluation, ...

  17. Introduction to Wiener's Article

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 1. Introduction to Wiener's Article. V Rajaraman. Reflections Volume 4 Issue 1 January 1999 pp 80-80. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/004/01/0080-0080. Author Affiliations.

  18. Indefinite articles and beyond

    NARCIS (Netherlands)

    Le Bruyn, B.S.W.

    2010-01-01

    This dissertation challenges the standard view on indefinite articles as argument markers and determiners that block bare nominal arguments. It argues for a more fine-grained view in which articles are poor in their semantics but rich in their pragmatic competition with bare nominals and other

  19. Low temperature study of nonstoichiometric titanium carbide

    International Nuclear Information System (INIS)

    Tashmetov, M.Yu.

    2005-05-01

    By low temperature neutron diffraction method was studied structure in nonstoichiometric titanium carbide from room temperature up to 12K. It is found of low temperature phase in titanium carbide- TiC 0.71 . It is established region and borders of this phase. It is determined change of unit cell parameter. (author)

  20. Corrosion comparisons between zirconium and titanium

    International Nuclear Information System (INIS)

    Yau Telin

    1992-01-01

    Zirconium and titanium are regarded as sister metals with excellent resistance to many corrosives. While these metals exhibit some similar corrosion properties, this paper discusses several major differences. The differences are found in chloride-free acids, acidic chloride solutions, salt solutions, alkaline solutions and organics. They are caused by the differences between the protective oxide films of zirconium and titanium. (orig.) [de

  1. Mineral resource of the month: titanium

    Science.gov (United States)

    Gambogi, Joseph

    2011-01-01

    Titanium is hip - at least when it comes to airplanes and jewelry. Known for its high strength-to weight ratio and its resistance to corrosion, titanium and its alloys can also be found in everything from knee replacements to eyeglass frames to baseball bats to fighter planes.

  2. Thermoexpanded graphite modification by titanium dioxide

    International Nuclear Information System (INIS)

    Semko, L.S.; Gorbik, P.P.; Chujko, O.O.; Kruchek, Ya.Yi.; Dzyubenko, L.S.; Orans'ka, O.Yi.

    2006-01-01

    A method of the synthesis of thermoexpanded graphite (TEG) powders coated by titanium dioxide is developed. The conversion of n-buthylorthotitanate into TiO 2 on the TEG surface is investigated. The optimal parameters of the synthesis and the structure of titanium dioxide clusters on the TEG surface are determined

  3. Appcelerator Titanium business application development cookbook

    CERN Document Server

    Bahrenberg, Benjamin

    2013-01-01

    Presented in easy to follow, step by step recipes, this guide is designed to lead you through the most important aspects of application design.Titanium developers who already have a basic knowledge of working with Appcelerator Titanium but want to further develop their knowledge for use with business applications

  4. Mechanical properties of biomedical titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Niinomi, M. [Toyohashi Univ. of Technol. (Japan). Sch. of Production Syst. Eng.

    1998-03-15

    Titanium alloys are expected to be much more widely used for implant materials in the medical and dental fields because of their superior biocompatibility, bioaffinity, corrosion resistance and specific strength compared with other metallic implant materials. Pure titanium and Ti-6Al-4V, in particular, Ti-6Al-4V ELI have been, however, mainly used for implant materials among various titanium alloys to date. V free alloys like Ti-6Al-7Nb and Ti-5Al-2.5Fe have been recently developed for biomedical use. More recently V and Al free alloys have been developed. Titanium alloys composed of non-toxic elements like Nb, Ta, Zr and so on with lower modulus have been started to be developed mainly in the USA. The {beta} type alloys are now the main target for medical materials. The mechanical properties of the titanium alloys developed for implant materials to date are described in this paper. (orig.) 17 refs.

  5. 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.

  6. The present status of dental titanium casting

    Science.gov (United States)

    Okabe, Toru; Ohkubo, Chikahiro; Watanabe, Ikuya; Okuno, Osamu; Takada, Yukyo

    1998-09-01

    Experimentation in all aspects of titanium casting at universities and industries throughout the world for the last 20 years has made titanium and titanium-alloy casting nearly feasible for fabricating sound cast dental prostheses, including crowns, inlays, and partial and complete dentures. Titanium casting in dentistry has now almost reached the stage where it can seriously be considered as a new method to compete with dental casting using conventional noble and base-metal alloys. More than anything else, the strength of titanium’s appeal lies in its excellent biocompatibility, coupled with its comparatively low price and abundant supply. Research efforts to overcome some problems associated with this method, including studies on the development of new titanium alloys suitable for dental use, will continue at many research sites internationally.

  7. Scientific Journal Articles

    Science.gov (United States)

    These are abstracts of peer-reviewed articles, authored by Office of Children's Health Protection staff. They cover topics including risk assessment for early life stages, inhalation dosimetry, and manganese in drinking water.

  8. Research Article Special Issue

    African Journals Online (AJOL)

    2016-05-15

    9867. Available online at http://www.jfas.info. Research Article. Special .... 809. Table 3. Content analysis of questioning level for each grade based on cognitive domain. (Pre-test). Group. Grade knowledge. Comprehension.

  9. Multilingual News Article Classification

    OpenAIRE

    Skjennum, Patrick L

    2016-01-01

    News is an ever-growing and global resource, reliant on robust distribution networks to spread information. This thesis investigates how exploiting semantic, contextual and ontological information may form a basis for a language independent news article classification system. In light of the above, a scalable multi-label news article classification system, based exclusively on extracted DBpedia entities, and a predetermined standardized set of fixed-size IPTC Media Topic categories, is p...

  10. Adsorption of hydrogen in titanium

    International Nuclear Information System (INIS)

    Martinez R, T.

    1995-01-01

    In this work the absorption of hydrogen in titanium plates using a constant volume system has been realized. The changes of temperature and pressure were used to monitor the progress of the absorption. A stainless steel vacuum chamber with volume of 4,333 cm 3 was used. A titanium sample of 45 x 5.4 x 0.3 cm was located in the center of the chamber. The sample was heated by an electrical source connected to the system. The sample was preconditioned with a vacuum-thermal treatment at 10 -6 mbar and 800 Centigrade degrees for several days. Absorption was observed at room temperature and also at higher temperatures. The room temperature absorption was in the pressure range of 1.0 x 10 3 to 2.5 x 10 3 mbar, and other absorptions were from 180 to 630 Centigrade degrees at 3.5 x 10 -1 to 1.3 x 10 3 mbar. It was found that the gas absorbed was function of the vacuum-thermal pre-conditioned treatment, pressure and temperature. When the first absorption was developed, additional absorptions were realized in short time. We measured the electrical resistivity of the sample in the experiments but we could not see important changes due to the absorption. (Author)

  11. An overview of the corrosion aspect of dental implants (titanium and its alloys

    Directory of Open Access Journals (Sweden)

    Chaturvedi T

    2009-01-01

    Full Text Available Titanium and its alloys are used in dentistry for implants because of its unique combination of chemical, physical, and biological properties. They are used in dentistry in cast and wrought form. The long term presence of corrosion reaction products and ongoing corrosion lead to fractures of the alloy-abutment interface, abutment, or implant body. The combination of stress, corrosion, and bacteria contribute to implant failure. This article highlights a review of the various aspects of corrosion and biocompatibility of dental titanium implants as well as suprastructures. This knowledge will also be helpful in exploring possible research strategies for probing the biological properties of materials.

  12. Non-Destructive Analysis of Basic Surface Characteristics of Titanium Dental Implants Made by Miniature Machining

    Science.gov (United States)

    Babík, Ondrej; Czán, Andrej; Holubják, Jozef; Kameník, Roman; Pilc, Jozef

    2016-12-01

    One of the most best-known characteristic and important requirement of dental implant is made of biomaterials ability to create correct interaction between implant and human body. The most implemented material in manufacturing of dental implants is titanium of different grades of pureness. Since most of the implant surface is in direct contact with bone tissue, shape and integrity of said surface has great influence on the successful osseointegration. Among other characteristics of titanium that predetermine ideal biomaterial, it shows a high mechanical strength making precise machining miniature Increasingly difficult. The article is focused on evaluation of the resulting quality, integrity and characteristics of dental implants surface after machining.

  13. Neutron absorbing article

    International Nuclear Information System (INIS)

    Naum, R.G.; Owens, D.P.; Dooher, G.I.

    1979-01-01

    A neutron absorbing article, in flat plate form and suitable for use in a storage rack for spent fuel, includes boron carbide particles, diluent particles and a solid, irreversibly cured phenolic polymer cured to a continuous matrix binding the boron carbide and diluent particles. The total conent of boron carbide and diluent particles is a major proportion of the article and the content of cured phenolic polymer present is a minor proportion. By regulation of the ratio of boron carbide particles to diluent particles, normally within the range of 1:9 and 9:1 and preferably within the range of 1:5 to 5:1, the neutron absorbing activity of the product may be controlled, which facilitates the manufacture of articles of particular absorbing activities best suitable for specific applications

  14. Neutron absorbing article

    International Nuclear Information System (INIS)

    Naum, R.G.; Owens, D.P.; Dooker, G.I.

    1981-01-01

    A neutron-absorbing article suitable for use in spent fuel racks is described. It comprises boron carbide particles, diluent particles, and a phenolic polymer cured to a continuous matrix. The diluent may be silicon carbide, graphite, amorphous carbon, alumina, or silica. The combined boron carbide-diluent phase contains no more than 2 percent B 2 O 3 , and the neutron-absorbing article contains from 20 to 40 percent phenol resin. The ratio of boron carbide to diluent particles is in the range 1:9 to 9:1

  15. Critiquing a research article

    International Nuclear Information System (INIS)

    Marshall, Gill

    2005-01-01

    This article explores certain concepts relating to critiquing research papers. These include considering the peer review process for publication, demonstrating the need for critiquing, providing a way to carefully evaluate research papers and exploring the role of impact factors. Whilst all these features are considered in this article, the focus is on presenting a systematic and comprehensive way of critiquing research papers. The information provided should be of use to the many radiographers, associated health professionals and undergraduate and postgraduate students embarking on research projects

  16. Development of the Fray-Farthing-Chen Cambridge Process: Towards the Sustainable Production of Titanium and Its Alloys

    Science.gov (United States)

    Hu, Di; Dolganov, Aleksei; Ma, Mingchan; Bhattacharya, Biyash; Bishop, Matthew T.; Chen, George Z.

    2018-02-01

    The Kroll process has been employed for titanium extraction since the 1950s. It is a labour and energy intensive multi-step semi-batch process. The post-extraction processes for making the raw titanium into alloys and products are also excessive, including multiple remelting steps. Invented in the late 1990s, the Fray-Farthing-Chen (FFC) Cambridge process extracts titanium from solid oxides at lower energy consumption via electrochemical reduction in molten salts. Its ability to produce alloys and powders, while retaining the cathode shape also promises energy and material efficient manufacturing. Focusing on titanium and its alloys, this article reviews the recent development of the FFC-Cambridge process in two aspects, (1) resource and process sustainability and (2) advanced post-extraction processing.

  17. Clinical bending of nickel titanium wires

    Directory of Open Access Journals (Sweden)

    Stephen Chain

    2015-01-01

    Full Text Available Since the evolution and the involvement of Nickel Titanium wires in the field of Orthodontics. The treatment plan has evolved with the use of low force Nickel Titanium wires. Because of their high springback, low stiffness, they are the key initial wires in leveling and alignment but have poor formability. Since poor formability limits its ability to create variable arch forms thus; limits the form of treatment. We have devised a method to bend the Nickel Titanium wires to help in our inventory but also customized the wire according to the treatment.

  18. Titanium exposure and yellow nail syndrome

    Directory of Open Access Journals (Sweden)

    Ali Ataya

    2015-01-01

    Full Text Available Yellow nail syndrome is a rare disease of unclear etiology. We describe a patient who develops yellow nail syndrome, with primary nail and sinus manifestations, shortly after amalgam dental implants. A study of the patient's nail shedding showed elevated nail titanium levels. The patient had her dental implants removed and had complete resolution of her sinus symptoms with no change in her nail findings. Since the patient's nail findings did not resolve we do not believe titanium exposure is a cause of her yellow nail syndrome but perhaps a possible relationship exists between titanium exposure and yellow nail syndrome that requires further studies.

  19. 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.

  20. 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.

  1. Research Article Special Issue

    African Journals Online (AJOL)

    2018-01-15

    Jan 15, 2018 ... ired to achieve the objective of ally in the field of Mechanical to the current market needs. discriminant analysis. Research Article. Special Issue ... Engineering field but fail to practice it. They only learn it in order .... question items led the highest reading with a percentage value of 98.67%, followed by GSS1.

  2. Research Article Special Issue

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    pc

    2017-10-17

    Oct 17, 2017 ... Electronic Commerce Research and Applications, 2012, 11(1):75-84. [16] Yue W S, Zin N A M. usabilty evaluation for history educational games. In 2nd. International Conference on Interaction Sciences: Information Technology, Culture and. Human, 2012,pp. 1019-1025. How to cite this article: Ramli R.Z ...

  3. Research Article Special Issue

    African Journals Online (AJOL)

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    6S):710-734. How to cite this article: Rizman ZI, Adnan J, Hashim FR, Yassin IM, Zabidi A, Zaman FK, Yeap KH. Development of hybrid drone (hydro) for surveillance application. J. Fundam. Appl. Sci., 2018, 10(1S),. 816-823.

  4. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2017-10-05

    Oct 5, 2017 ... Journal of Fundamental and Applied Sciences. ISSN 1112-9867. Available online at http://www.jfas.info. Research Article. Special Issue .... of use. Three critical success factors of e-learning (instructor characteristics, student characteristics .... Total of 95 questionnaires were used for further data analysis.

  5. Research Article Special Issue

    African Journals Online (AJOL)

    2017-11-10

    Nov 10, 2017 ... dia University, 75450 Bukit ter Sciences, UniversitiSains rld by storm. The conventional achine to machine tween this communications, it vity. On the basis of these, this g of IoT device simulations in ressing the security and packet tiki operating system to test, es, sensors and network works. Research Article.

  6. Research Article Special Issue

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    2017-08-08

    Aug 8, 2017 ... to select the analogues of materials for the manufacture of products with special properties. The technical ... The aim of this article is to investigate the technological and mechanical properties of GH304. T14992-1994 (the ... The tests were carried out with the automated compilation of protocols. The test ...

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    African Journals Online (AJOL)

    2017-09-10

    Sep 10, 2017 ... or attacking perceived. Research Article. Special Issue ... approach which is using National Instruments (NI) LabVIEW Biomedical Workbench with data acquisition (DAQ) device to ..... 13 shows that hemoglobin is greatly absorbed the green color wavelength (550 nm), if compared to red (650 nm) and blue ...

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    African Journals Online (AJOL)

    2017-08-08

    Aug 8, 2017 ... based on a new instrument tivariate analysis was used to port towards opiate dependents. y a cluster analysis of the PCA ntify the characteristics of high ns which have high variation in ion), and a further analysis by ps. Cluster 2 had the highest ter 1 with moderate variation in cluster 3. Research Article.

  9. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2017-11-24

    Nov 24, 2017 ... energy resources (SER)in metallurgical production can be divided into potential energy sources ... n heat pump with a heat circulating water: a y of power supply of the energy efficiency. elated to the amount of n dioxide emission. Research Article .... plants are electric steel smelting and oxyge systems at ...

  10. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2017-11-24

    Nov 24, 2017 ... ABSTRACT. The article is devoted to the issue of grammatical approach application during the teaching of ... communicative communication tasks leads to grammatical, lexical and strategic complication of speech ... Another approach to the organization of speech activity is demonstrated by D.I. Izarenkov.

  11. 9 ORIGINAL ARTICLE

    African Journals Online (AJOL)

    Dr Oboro VO

    ORIGINAL ARTICLE. AFRICAN JOURNAL OF CLINICAL AND EXPERIMENTAL MICROBIOLOGY JAN 2011. ISBN 1595-689X VOL 12 No. 1 ... skin of patients and environmental surfaces in the immediate vicinity of the patients (4). ... it helps in preventing chemically related occupational hazards and up to 80% of infections, ...

  12. 66 ORIGINAL ARTICLE

    African Journals Online (AJOL)

    boaz

    ORIGINAL ARTICLE. AFRICAN JOURNAL OF CLINICAL AND EXPERIMENTAL MICROBIOLOGY JAN 2016 ISBN 1595-689X VOL 17 No.1 ..... WOMEN. Social characteristics. No. examined (n = 310). No. positive. (n=30) (%). Education. Illiterate. Primary. Secondary. Tertiary. Occupation. Civil servant. House wife. Students.

  13. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    Published online: 24 November 2017. ABSTRACT. The control problems for technological objects with distributed state variables and large dead times are discussed in the present article. The creation of control systems using the object model in the control loop is considered. It is shown that the most effective approach for ...

  14. Research Article Special Issue

    African Journals Online (AJOL)

    2016-05-15

    May 15, 2016 ... PENN, Bachinghamshire. [16]Rorty, R. (1979). Philosophy and the mirror of nature. Princeton university press. [17]Salinger, J. D. (1951). The catcher in the rye. Little, Brown and Company. [18]Zizek, S. (2001). Enjoy you symptom: Jacques Lacan in Hollywood and out. Routledge. How to cite this article:.

  15. Research Article Special Issue

    African Journals Online (AJOL)

    2016-05-15

    May 15, 2016 ... "The facts show that the use of new technologies in the 21st century will have a profound impact on human social life and education and education is certainly not exempt from these changes. Research in education, states the article that information technology has been mainly used in regular education ...

  16. Full Length Research Article

    African Journals Online (AJOL)

    Administrator

    Out of the 320 male sheep examined, 87(27.2%) were infected, while 9(19.1%) of the 47 females examined were infected (Table 2). Infection varied from one abattoir to another. Age related distribution of P. cervi is shown in Table 3. Out of 356 adult sheep (>2yrs) examined, 35. Full Length Research Article. 12 ...

  17. Research Article Special Issue

    African Journals Online (AJOL)

    2018-01-15

    Jan 15, 2018 ... crisis indicator at national level using k-means cluster analysis. IOP Conference Series: Materials Science and Engineering, 2017, 166(1):1-9. How to cite this article: Hidayat Y, Purwandari T, Sukono, Supian S, Juahir H, Kamarudin MKA, Ireana Yusra AF. Improving unprecedented restlessness as the new ...

  18. STOMATOLOGICAL JOURNAL (SELECTED ARTICLES).

    Science.gov (United States)

    This article discusses the clinical symptoms of lithiasis of the parotid salivary gland, examination methods that allow detection of sialoliths... lithiasis treated at the Dental Surgery Clinic at Zabrze are summarized: 88% of all salivary gland lithiasis is submaxillary; it appears most frequently

  19. Research Article Special Issue

    African Journals Online (AJOL)

    2016-05-15

    May 15, 2016 ... accounting, Islamic Azad University, Rasht, Iran ... except the effect of management participation on marketing innovation and product innovation ... Available online at http://www.jfas.info. Research Article. Special Issue. Journal of Fundamental and Applied Sciences is licensed under a Creative Commons ...

  20. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2017-10-17

    Oct 17, 2017 ... We are listed under Research Associations category. ... SKJalan Hang he validity showedstrong eanwhile the reliability of sess the flexibility of the nts should be tested with. Research Article. Special Issue ... Studies have shown that the problems of diseases such as hypertension, heart disease and.

  1. Research Article Special Issue

    African Journals Online (AJOL)

    2016-05-15

    May 15, 2016 ... pavements (JCP). With using a 3- transfer efficiency (LTE) of the ransverse prestressing with various restressing although increased the jacent is minor and engineers can e higher prestressing force, might prestressing for more than 400 kN element; Load transfer efficiency. Research Article. Special Issue ...

  2. 158 ORIGINAL ARTICLE

    African Journals Online (AJOL)

    boaz

    158. ORIGINAL ARTICLE. AFRICAN JOURNAL OF CLINICAL AND EXPERIMENTAL MICROBIOLOGY JULY 2016 ISBN 1595-689X VOL17 No. 3. AJCEM/ .... A single colony was inoculated into Mueller–Hinton broth and incubated for 20 ..... countries, including Taiwan, Japan, Korea, Thailand,. Spain, Mexico, Saudi Arabia, ...

  3. 1 RESEARCH ARTICLE

    Indian Academy of Sciences (India)

    HP

    RESEARCH ARTICLE. Study of Association of Forkhead Box P3 (FOXP3) Gene Polymorphisms with Unexplained Recurrent. Spontaneous Abortions in Indian Population. Shivani Mishra, Anukool Srivastava, Kausik Mandal, Shubha R Phadke*. Department of Medical Genetics, Sanjay Gandhi Postgraduate Institute of ...

  4. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2017-11-24

    Nov 24, 2017 ... Blue Lakes area and the history of flour milling industry, using water mills, were studied. The article presents the .... through his father, for 20 years before the 1917 revolution. To date, these objects ... included in the pond, the fourth cavity was located in the lower duct of the pond, and the fifth karst cavity was ...

  5. Research Article Special Issue

    African Journals Online (AJOL)

    2016-07-16

    Jul 16, 2016 ... This article studies the impact of e-customer relationship management system in banking industry from the ... CRM: it includes the banks that do not have communication channels to provide possibility of recognizing .... customer's loyalty and intent of transferring are the dependent variables of the research.

  6. Research Article Special Issue

    African Journals Online (AJOL)

    2017-10-05

    Oct 5, 2017 ... th Exogenous Input (NARX). PSO) algorithm. The system ected from Steam Distillation e Information Criterion, Model. ) for optimization process of t the FPE criterion model was set, small fitness value he accuracy was evaluated by ation and histogram tests. ure; NARX; particle swarm. Research Article.

  7. Research Article Special Issue

    African Journals Online (AJOL)

    2016-05-15

    May 15, 2016 ... production. In this article, the method of producing energy from these algae along with their application in sustainable architecture has been investigated. For this purpose, a few .... cyanobacteria, “chosen for its rich green hue, light absorbency, and culinary qualities,” set in alkaline water and housed in ...

  8. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2017-11-24

    Nov 24, 2017 ... 3Associate Professor of the Department of Pedagogy and Psychology of Childhood, Bryansk ... The article examines the phenomenon of the interactive educational environment as a carefully constructed ... Key words: dialogue environment education, dialogue, axiosphere of a future teacher, socio- cultural ...

  9. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    Published online: 08 August 2017. ABSTRACT. Article purpose: to consider the possibility of Hilbert-Huang transformation (HHT) use for vibration-acoustic control of a fuel dispenser operation in an internal combustion engine HHT was proposed by Norden Huang in 1995 to study the surface waves of typhoons. In recent.

  10. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2017-11-24

    , launched in. 2005, in comparison with Web of Science and expresses his view on how it can be improved. At the same time the analysis of the whole range of articles on this topic shows that the RSCI is currently applied to ...

  11. Research Article Special Issue

    African Journals Online (AJOL)

    2017-10-17

    Oct 17, 2017 ... via brain waves study by using electroencephalogram (EEG). International Journal on. Advanced Science, Engineering and Information Technology, 2016, 6(6):1005-1011. How to cite this article: Anoor M M, Khairul AnwarK H, Megat Ali M S A and Jahidin A H. Classification of students' IQ level using ...

  12. Research Article Special Issue

    African Journals Online (AJOL)

    2017-09-10

    Sep 10, 2017 ... List here those individuals who provided help during the research (e.g., providing language help, writing assistance or proof reading the article, etc.). 6. REFERENCES. [1] Waller P., Weerakkody V. Digital government: overcoming the systemic failure of transformation. London: Brunel University Press, 2016 ...

  13. 18 ORIGINAL ARTICLE

    African Journals Online (AJOL)

    Boaz

    ORIGINAL ARTICLE. AFRICAN JOURNAL OF CLINICAL AND EXPERIMENTAL MICROBIOLOGY JANUARY 2018 ISBN 1595-689X VOL19 No.1 ... Le Staphylococcus aureus était le plus souvent isolé des deux mains et des deux sexes (29,2%, 27,3%), suivi par le SARM (22,1%, 24,7% respectivement). Conclusions: Le ...

  14. Titanium

    DEFF Research Database (Denmark)

    Fage, Simon W; Muris, Joris; Jakobsen, Stig S

    2016-01-01

    most of the studies reviewed have important limitations, Ti seems not to penetrate a competent skin barrier, either as pure Ti, alloy, or as Ti oxide NPs. However, there are some indications of Ti penetration through the oral mucosa. We conclude that patch testing with the available Ti preparations...... evaluation. Reports on clinical allergy and adverse events have rarely been published. Whether this is because of unawareness of possible adverse reactions to this specific metal, difficulties in detection methods, or the metal actually being relatively safe to use, is still unresolved....

  15. Low-valent pentafulvene titanium dinitrogen complex as a precursor for cationic titanium complexes

    NARCIS (Netherlands)

    Scherer, Axel; Haase, Detlev; Saak, Wolfgang; Beckhaus, Ruediger; Meetsma, Auke; Bouwkamp, Marco W.; Beckhaus, Rüdiger

    2009-01-01

    Treatment of titanium dinitrogen complex [Cp*(eta(6)-C(5)H(4)=C(10)H(14))Ti](2)(mu-N(2)) (1) with ferrocenium borate, [Cp(2)Fe][BPh(4)], in THF results in oxidation of the titanium center, affording the titanium(IV) pentafulvene compound [Cp*(eta(6)-C(5)H(4)=C(10)H(14))Ti(THF)][BPh(4)] (2).

  16. Prospective, randomized comparison of cobalt-chrome and titanium trilock femoral stems.

    Science.gov (United States)

    Healy, William L; Tilzey, John F; Iorio, Richard; Specht, Lawrence M; Sharma, Sanjeev

    2009-09-01

    The purpose of this article was to demonstrate the efficacy of a cementless, flat, tapered wedge femoral stem and compare cobalt-chrome and titanium femoral stems with this design. Three hundred ninety femoral stems observed for a mean of 4.7 years (2.0-8.9 years) were prospectively evaluated with clinical and radiographic follow-up. Hips were stratified by Dorr classification, bone stock (femoral index), size of implant used, and material of femoral implant. Survivorship of the femoral stem at 8.9 years was 99.8% with no significant difference between cohorts. Thigh pain (4.9%) was more common with cobalt-chrome femoral stems (6.5%) than titanium femoral stems (3.1%). The flat, tapered wedge femoral stem design provides excellent femoral reconstruction in total hip arthroplasty. On the basis of this study, we use titanium femoral stems.

  17. [Susceptibility to infections and behavior of stainless steel : Comparison with titanium implants in traumatology].

    Science.gov (United States)

    Haubruck, Patrick; Schmidmaier, Gerhard

    2017-02-01

    Despite modern treatment options, implant-associated infections (IAI) remain a severe and challenging complication in the treatment of trauma patients. Almost 30 years after the introduction of implants made of titanium alloy into the treatment of trauma patients, there is still no uniform consensus regarding the clinical benefit of titanium alloy in the context of patients with IAI. We sought to determine if implants made of titanium alloy have been proven to be less susceptible regarding IAI in contrast to implants made of stainless steel. A review of the current literature on IAI in association with the utilized implant material was conducted. Relevant articles from the years 1995 to 2016 were searched in the PubMed database. A total of 183 articles were identified and all abstracts were reviewed for relevance. A total of 14 articles met the inclusion criteria and were stratified according to the level of evidence and furthermore evaluated regarding the influence of the implant material on IAI. Considerable debate remains concerning the influence of the implant material on the susceptibility to IAI; however, the available literature shows that despite slight tendencies, there is no proof of titanium alloy being favorable in the susceptibility to IAI. Furthermore, the literature shows that the design of plates for osteosynthesis might influence IAI. In particular, plates that cause less soft tissue damage and preserve perfusion of the periosteum proved to be beneficial regarding IAI.

  18. Synthesis of Titanium Oxycarbide from Titanium Slag by Methane-Containing Gas

    Science.gov (United States)

    Dang, Jie; Fatollahi-Fard, Farzin; Pistorius, Petrus Christiaan; Chou, Kuo-Chih

    2018-02-01

    In this study, reaction steps of a process for synthesis of titanium oxycarbide from titanium slag were demonstrated. This process involves the reduction of titanium slag by a methane-hydrogen-argon mixture at 1473 K (1200 °C) and the leaching of the reduced products by hydrofluoric acid near room temperature to remove the main impurity (Fe3Si). Some iron was formed by disproportionation of the main M3O5 phase before gaseous reduction started. Upon reduction, more iron formed first, followed by reduction of titanium dioxide to suboxides and eventually oxycarbide.

  19. Effect of plasma nitriding and titanium nitride coating on the corrosion resistance of titanium.

    Science.gov (United States)

    Wang, Xianli; Bai, Shizhu; Li, Fang; Li, Dongmei; Zhang, Jing; Tian, Min; Zhang, Qian; Tong, Yu; Zhang, Zichuan; Wang, Guowei; Guo, Tianwen; Ma, Chufan

    2016-09-01

    The passive film on the surface of titanium can be destroyed by immersion in a fluoridated acidic medium. Coating with titanium nitride (TiN) may improve the corrosion resistance of titanium. The purpose of this in vitro study was to investigate the effect of duplex treatment with plasma nitriding and TiN coating on the corrosion resistance of cast titanium. Cast titanium was treated with plasma nitriding and TiN coating. The corrosion resistance of the duplex-treated titanium in fluoride-containing artificial saliva was then investigated through electrochemical and immersion tests. The corroded surface was characterized by scanning electron microscopy (SEM) with energy-dispersive spectroscopy surface scan analysis. The data were analyzed using ANOVA (α=.05) RESULTS: Duplex treatment generated a dense and uniform TiN film with a thickness of 4.5 μm. Compared with untreated titanium, the duplex-treated titanium displayed higher corrosion potential (Ecorr) values (Pcorrosion current density (Icorr) values (Pcorrosion resistance of cast titanium in a fluoride-containing environment. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  20. Biomechanical evaluation of the locking titanium cable in the fixture of distal tibiofibular syndesmosis injury

    Directory of Open Access Journals (Sweden)

    Shu-zhi YAO

    2016-08-01

    Full Text Available Objective  The article aims at evaluating the biological properties of tibiofibular titanium cable fixation device in terms of both anti-separation and stress shielding by comparison to the interior fixation with lag screw based on experimental observation. Methods  Six corpse ankle specimens were first tested of pressure-separation and stress measurement, the data from which were compared to the normal group, and then a syndesmosis injury model was established. All the samples are randomly divided into 2 groups of 3 specimens each, which were treated with tibiofibula locked titanium cable and lag screw fixation respectively for syndesmosis injury. Then, the samples were tested for pressure-separation and stress measurement. The biomechanical properties as anti-separation ability and stress shielding were analyzed and compared between the two fixation method. Results  Both tibiofibula locked titanium cables and lag screws were able to provide enough strong lateral anti-separation ability, but strong fixation screws were inferior to tibiofibular titanium cable fixation device in fibular longitudinal stress transduction. Conclusion  Tibiofibular titanium cable fixation device not only provide sufficient lateral anti-separation, but also reduces the tibial and fibular longitudinal stress shielding, thus being superior to the traditional lag screw in biomechanical properties. DOI: 10.11855/j.issn.0577-7402.2016.07.09

  1. Neutron scattering and models: Titanium

    Energy Technology Data Exchange (ETDEWEB)

    Smith, A.B.

    1997-07-01

    Differential neutron elastic-scattering cross sections of elemental titanium were measured from 4.5 {r_arrow} 10.0 MeV in incident energy increments of {approx} 0.5 MeV. At each energy the measurements were made at forty or more scattering angles distributed between {approx} 17 and 160{degree}. Concurrently, differential neutron inelastic-scattering cross sections were measured for observed excitations of 0.975 {+-} 0.034, 1.497 {+-} 0.033, 2.322 {+-} 0.058, 3.252 {+-} 0.043, 3.700 {+-} 0.093, 4.317 {+-} 0.075 and 4.795 {+-} 0.100 MeV. All of the observed inelastically-scattered neutron groups were composites of contributions from several isotopes and/or levels. The experimental results were used to develop energy-average optical, statistical and coupled-channels models.

  2. Erbium diffusion in titanium dioxide

    Directory of Open Access Journals (Sweden)

    Louise Basse

    2017-04-01

    Full Text Available The diffusivity of erbium in the anatase phase of titanium dioxide (TiO2 has been studied for various temperatures ranging from 800 °C to 1, 000 °C. Samples of TiO2, with a 10 nm thick buried layer containing 0.5 at% erbium, were fabricated by radio-frequency magnetron sputtering and subsequently heat treated. The erbium concentration profiles were measured by secondary ion mass spectrometry, allowing for determination of the temperature-dependent diffusion coefficients. These were found to follow an Arrhenius law with an activation energy of ( 2.1 ± 0.2 eV. X-ray diffraction revealed that the TiO2 films consisted of polycrystalline grains of size ≈ 100 nm.

  3. Tweeting News Articles

    Directory of Open Access Journals (Sweden)

    Marco Toledo Bastos

    2013-09-01

    Full Text Available In this article we investigate the impact of social media readership to the editorial profile of newspapers. We analyze tweets containing links to news articles from eight of the largest national newspapers in the United States, United Kingdom, Spain, Brazil, and Germany. The data collection follows the first two weeks of October 2012 and includes 2,842,699 tweets with links to news articles. Twitter-shortened links were resolved using a three-pass routine and assigned to 1 of the 21 newspaper sections. We found the concentration of links to news articles posted by top users to be lower than reported in the literature and the strategy of relaying headlines on Twitter via automatic news aggregators (feeds to be inefficient. The results of this investigation show which sections of a newspaper are the most and least read by readers in different parts of the world, with German readers placing greater emphasis on Politics and Economy; Brazilians on Sports and Arts; Spaniards on Local and National news; Britons and Americans on Opinion and World news. We also found that German and Spanish readers are more likely to read multiple national newspapers, while British readers more often resort to foreign sources of news. The results confirm that feedback to news items from a large user base is pivotal for the replication of content and that newspapers and news items can be clustered according to the editorial profile and principles of newsworthiness inherited from legacy media. The results of this investigation shed light onto the networked architecture of journalism that increasingly depends on readership agency.

  4. Research Article Special Issue

    African Journals Online (AJOL)

    2016-05-15

    May 15, 2016 ... ABSTRACT. In this article, we simulate thermal effects on the electron transfer rate from three quantum dots. CdSe, CdS and CdTe to three metal oxides TiO2, SnO2 and ZnO2 in the presence of four blocking layers ZnS, ZnO, TiO2 and Al2O3, in a porous quantum dot sensitized solar cell. (QDSSC) structure ...

  5. Dense ceramic articles

    International Nuclear Information System (INIS)

    Cockbain, A.G.

    1976-01-01

    A method is described for the manufacture of articles of substantially pure dense ceramic materials, for use in severe environments. Si N is very suitable for use in such environments, but suffers from the disadvantage that it is not amenable to sintering. Some disadvantages of the methods normally used for making articles of Si N are mentioned. The method described comprises mixing a powder of the substantially pure ceramic material with an additive that promotes densification, and which is capable of nuclear transmutation into a gas when exposed to radiation, and hot pressing the mixture to form a billet. The billet is then irradiated to convert the additive into a gas which is held captive in the billet, and it is then subjected to a hot forging operation, during which the captive gas escapes and an article of substantially pure dense ceramic material is forged. The method is intended primarily for use for Si N, but may be applied to other ceramic materials. The additive may be Li or Be or their compounds, to the extent of at least 5 ppm and not more than 5% by weight. Irradiation is effected by proton or neutron bombardment. (UK)

  6. Titanium Heat Pipe Thermal Plane, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Thermacore Inc. proposes an innovative titanium heat pipe thermal plane for passive thermal control of individual cells within a fuel cell stack. The proposed...

  7. Corrosion resistance of titanium alloys for dentistry

    International Nuclear Information System (INIS)

    Laskawiec, J.; Michalik, R.

    2001-01-01

    Titanium and its alloys belong to biomaterials which the application scope in medicine increases. Some properties of the alloys, such as high mechanical strength, low density, low Young's modulus, high corrosion resistance and good biotolerance decide about it. The main areas of the application of titanium and its alloys are: orthopedics and traumatology, cardiosurgery, faciomaxillary surgery and dentistry. The results of investigations concerning the corrosion resistance of the technical titanium and Ti6Al14V alloy and comparatively a cobalt alloy of the Vitallium type in the artificial saliva is presented in the work. Significantly better corrosion resistance of titanium and the Ti6Al14V than the Co-Cr-Mo alloy was found. (author)

  8. Titanium nitride nanoparticles for therapeutic applications

    DEFF Research Database (Denmark)

    Guler, Urcan; Kildishev, Alexander V.; Boltasseva, Alexandra

    2014-01-01

    Titanium nitride nanoparticles exhibit plasmonic resonances in the biological transparency window where high absorption efficiencies can be obtained with small dimensions. Both lithographic and colloidal samples are examined from the perspective of nanoparticle thermal therapy. © 2014 OSA....

  9. Titanium Nanocomposite: Lightweight Multifunction Structural Material

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to research and develop lightweight metal matrix nanocomposites (MMnC) using a Titanium (Ti) metal matrix. Ti MMnC will crosscut the advancement of both...

  10. Titanium Heat Pipe Thermal Plane, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of the Phase II program is to complete the development of the titanium heat pipe thermal plane and establish all necessary steps for production of this...

  11. Titanium Brazing for Structures and Survivability

    National Research Council Canada - National Science Library

    Doherty, Kevin J; Tice, Jason R; Szewczyk, Steven T; Glide, Gary A

    2007-01-01

    Titanium is a candidate as a structural material for all new tactical and armored ground vehicles, because of its high strength-to-weight ratio, excellent corrosion resistance, and inherent ballistic resistance...

  12. Interfacial reactions between titanium and borate glass

    Energy Technology Data Exchange (ETDEWEB)

    Brow, R.K. [Sandia National Labs., Albuquerque, NM (United States); Saha, S.K.; Goldstein, J.I. [Lehigh Univ., Bethlehem, PA (United States). Dept. of Materials Science

    1992-12-31

    Interfacial reactions between melts of several borate glasses and titanium have been investigated by analytical scanning electron microscopy (SEM) and x-ray photoelectron spectroscopy (XPS). A thin titanium boride interfacial layer is detected by XPS after short (30 minutes) thermal treatments. ASEM analyses after longer thermal treatments (8--120 hours) reveal boron-rich interfacial layers and boride precipitates in the Ti side of the interface.

  13. Free Form Low Cost Fabrication Using Titanium

    Science.gov (United States)

    2007-06-29

    better than that of austenitic or ferritic stainless. Alloys can have ultimate strengths comparable to iron base superalloys , such as A286, or cobalt ...nickel-base superalloys . "* The tensile strength as an alloy of titanium can be comparable to that of lower-strength marterisitic stainless and is...approximately four times that of stainless steel, is comparable to that of superalloys . "* Titanium is exceptionally corrosion resistant. It often exceeds the

  14. Progress in Titanium Metal Powder Injection Molding

    OpenAIRE

    German, Randall M.

    2013-01-01

    Metal powder injection molding is a shaping technology that has achieved solid scientific underpinnings. It is from this science base that recent progress has occurred in titanium powder injection molding. Much of the progress awaited development of the required particles with specific characteristics of particle size, particle shape, and purity. The production of titanium components by injection molding is stabilized by a good understanding of how each process variable impacts density and im...

  15. PRODUCTION OF WELDMENTS FROM SINTERED TITANIUM ALLOYS

    Directory of Open Access Journals (Sweden)

    A. YE. Kapustyan

    2014-04-01

    Full Text Available Purpose. Limited application of details from powder titanium alloys is connected with the difficulties in obtaining of long-length blanks, details of complex shape and large size. We can solve these problems by applying the welding production technology. For this it is necessary to conduct a research of the structure and mechanical properties of welded joints of sintered titanium alloys produced by flash welding. Methodology. Titanium industrial powders, type PT5-1 were used as original substance. Forming of blanks, whose chemical composition corresponded to BT1-0 alloy, was carried out using the powder metallurgy method. Compounds were obtained by flash welding without preheating. Microstructural investigations and mechanical tests were carried out. To compare the results investigations of BT1-0 cast alloy were conducted. Findings. Samples of welded joints of sintered titanium blanks from VT1-0 alloy using the flash butt welding method were obtained. During welding the microstructure of basic metal consisting of grains of an a-phase, with sizes 40...70 mkm, is transformed for the seam weld and HAZ into the lamellar structure of an a-phase. The remaining pores in seam weld were practically absent; in the HAZ their size was up to 2 mkm, with 30 mkm in the basic metal. Attainable level of mechanical properties of the welded joint in sintered titanium alloys is comparable to the basic metal. Originality. Structure qualitative changes and attainable property complex of compounds of sintered titanium alloys, formed as a result of flash butt welding were found out. Practical value. The principal possibility of high-quality compounds obtaining of sintered titanium alloys by flash welding is shown. This gives a basis for wider application of sintered titanium alloys due to long-length blanks production that are correspond to deformable strand semi finished product.

  16. Amorphouslike diffraction pattern in solid metallic titanium

    DEFF Research Database (Denmark)

    Wang, Y.; Fang, Y.Z.; Kikegawa, T.

    2005-01-01

    Amorphouslike diffraction patterns of solid elemental titanium have been detected under high pressure and high temperature using in situ energy-dispersive x-ray diffraction and a multianvil press. The onset pressure and the temperature of formation of amorphous titanium is found to be close...... for preparing single-element bulk amorphous metals. The results reported may open a new way to preparing single-element bulk amorphous metals with a high thermal stability....

  17. Backscatter radiation at tissue-titanium interfaces

    International Nuclear Information System (INIS)

    Rosengren, B.; Wulff, L.; Carlsson, E.; Carlsson, J.; Strid, K.G.; Montelius, A.

    1993-01-01

    The induced secondary electrons from a metal surface by diagnostic X-rays are thought to contribute to cell damage near the tissue-metal boundaries of metal implants. Titanium implants are becoming increasingly more popular for tissue reconstructions and it is rather often desirable to take radiographs of the operated area. In this study we compared the biological effects of radiation on cultured mammalian test cells grown on titanium plates with the radiation effects on cells that were grown on plastic control plates. In order to study the acute radiation effects on cell growth it was necessary to work with rather high radiation doses (0.7-5 Gy). Photon energies, suitable for diagnostic radiography in odontology, 65 kV, were applied. We found that the cells grown on titanium plates were, in terms of the applied dose in the surrounding culture medium, more sensitive to the irradiations than the cells growing on plastic plates. The survival curve for the cells on titanium had a steeper slope, showed no shoulder in the low-dose region and looked like curves normally obtained for high LET radiation. It was not possible to resolve to what degree the titanium-dependent changes were due to an increased dose near the titanium surface or to a change in the radiobiological effectiveness. Although there was a significant decrease in cellular survival near the metal, postoperative intraoral radiography after titanium implantations need not be excluded. The maximal doses given in odontological X-ray examinations are less than 1 mGy and, if the results in this study are applied, the biological effects near the titanium implant will correspond to biological effects in soft tissue of doses less than 20 mGy which is lower than the doses that give acute effects. The risk of acute healing disturbances are significant only at much higher radiation doses. (orig.)

  18. Hydrocarbon Deposition Attenuates Osteoblast Activity on Titanium

    Science.gov (United States)

    Hayashi, R.; Ueno, T.; Migita, S.; Tsutsumi, Y.; Doi, H.; Ogawa, T.; Hanawa, T.; Wakabayashi, N.

    2014-01-01

    Although the reported percentage of bone-implant contact is far lower than 100%, the cause of such low levels of bone formation has rarely been investigated. This study tested the negative biological effect of hydrocarbon deposition onto titanium surfaces, which has been reported to be inevitable. Osteogenic MC3T3-E1 cells were cultured on titanium disks on which the carbon concentration was experimentally regulated to achieve carbon/titanium (C/Ti) ratios of 0.3, 0.7, and 1.0. Initial cellular activities such as cell attachment and cell spreading were concentration-dependently suppressed by the amount of carbon on the titanium surface. The osteoblastic functions of alkaline phosphatase activity and calcium mineralization were also reduced by more than 40% on the C/Ti (1.0) surface. These results indicate that osteoblast activity is influenced by the degree of hydrocarbon contamination on titanium implants and suggest that hydrocarbon decomposition before implant placement may increase the biocompatibility of titanium. PMID:24868012

  19. The effect of titanium surface treatment on the interfacial strength of titanium – Thermoplastic composite joints

    NARCIS (Netherlands)

    Su, Yibo; de Rooij, Matthijn; Grouve, Wouter; Akkerman, Remko

    2017-01-01

    Co-consolidated titanium – carbon fibre reinforced thermoplastic composite hybrid joints show potential for application in aerospace structures. The strength of the interface between the titanium and the thermoplastic composite is crucial for the strength of the entire hybrid joint. Application of a

  20. Artefacts in multimodal imaging of titanium, zirconium and binary titanium-zirconium alloy dental implants: an in vitro study.

    Science.gov (United States)

    Smeets, Ralf; Schöllchen, Maximilian; Gauer, Tobias; Aarabi, Ghazal; Assaf, Alexandre T; Rendenbach, Carsten; Beck-Broichsitter, Benedicta; Semmusch, Jan; Sedlacik, Jan; Heiland, Max; Fiehler, Jens; Siemonsen, Susanne

    2017-02-01

    To analyze and evaluate imaging artefacts induced by zirconium, titanium and titanium-zirconium alloy dental implants. Zirconium, titanium and titanium-zirconium alloy implants were embedded in gelatin and MRI, CT and CBCT were performed. Standard protocols were used for each modality. For MRI, line-distance profiles were plotted to quantify the accuracy of size determination. For CT and CBCT, six shells surrounding the implant were defined every 0.5 cm from the implant surface and histogram parameters were determined for each shell. While titanium and titanium-zirconium alloy induced extensive signal voids in MRI owing to strong susceptibility, zirconium implants were clearly definable with only minor distortion artefacts. For titanium and titanium-zirconium alloy, the MR signal was attenuated up to 14.1 mm from the implant. In CT, titanium and titanium-zirconium alloy resulted in less streak artefacts in comparison with zirconium. In CBCT, titanium-zirconium alloy induced more severe artefacts than zirconium and titanium. MRI allows for an excellent image contrast and limited artefacts in patients with zirconium implants. CT and CBCT examinations are less affected by artefacts from titanium and titanium-zirconium alloy implants compared with MRI. The knowledge about differences of artefacts through different implant materials and image modalities might help support clinical decisions for the choice of implant material or imaging device in the clinical setting.

  1. Will nonaerospace applications for titanium ever grow?

    Science.gov (United States)

    Katrak, Firoze E.; Servi, I. S.; Agarwal, J. C.

    1991-07-01

    Confronted with the currently attractive aerospace markets, titanium producers could choose to minimize their promotional effort in the nonaerospace sector. In such a case, primary producers would continue to give some support to a few nonaerospace market segments but would minimize product and market development in most other areas. Such a modus operandi is quite likely, in which case the 1990s may turn out to be as disappointing for the industrial application of titanium as were the 1980s. Such a trend is not desirable for titanium producers for two reasons: the military aerospace market is likely to shrink in the future,8 and the titanium content of commercial jet engines will decline.9 Thus, titanium producers need to adopt a strategy to increase nonaerospace applications. Such a strategy must accomplish at least the following: • Commit to reducing titanium mill product costs. • Convince potential users that titanium (sponge and) mill products will be available at a sustained cost much below the current cost. No radically new technologies are necessaryzzto meet the target sponge costs (i.e., the current processes can meet cost targets with plant and practice changes). • Begin developing new alloys specifically tailored to nonaerospace applications and lower-cost mill products. If and when new alloys become available, the potential growth in nonaerospace uses would be greater than the 1-10-100 rule, which applies to existing commercially pure titanium. • Work toward reducing value-added component costs by achieving cost reductions in secondary fabrication for selected niche applications. • Offer application engineering and technical support services, including the establishment of training centers (e.g., for field welding). • Develop estimates of cost effectiveness in target applications that will convince the users. If a strategy incorporating these elements is not adopted by titanium producers because of the short-term strength of aerospace demand

  2. The Equilibrium Between Titanium Ions and Titanium Metal in NaCl-KCl Equimolar Molten Salt

    Science.gov (United States)

    Wang, Qiuyu; Song, Jianxun; Hu, Guojing; Zhu, Xiaobo; Hou, Jungang; Jiao, Shuqiang; Zhu, Hongmin

    2013-08-01

    The equilibrium between metallic titanium and titanium ions, 3Ti2+ ⇌ 2Ti3+ + Ti, in NaCl-KCl equimolar molten salt was reevaluated. At a fixed temperature and an initial concentration of titanium chloride, the equilibrium was achieved by adding an excess amount of sponge titanium in assistant with bubbling of argon into the molten salt. The significance of this work is that the accurate concentrations of titanium ions have been obtained based on a reliable approach for taking samples. Furthermore, the equilibrium constant {{K}}_{{C}} = (x_{{{{Ti}}^{{ 3 { + }}} }}^{{eql}} )3 /(x_{{{{Ti}}^{{ 2 { + }}} }}^{{eql}} )2 was calculated through the best-fitting method under the consideration of the TiOCl dissolution. Indeed, the final results have disclosed that the stable value of KC could be achieved based on all modifications.

  3. Pulvermetallurgisch durch Reaktionssintern hergestelltes Bauteil aus einem Titanaluminid-Werkstoff und Verfahren zu seiner Herstellung

    OpenAIRE

    Kieback, B.; Boehm, A.; Weißgärber, T.

    2003-01-01

    DE 10228924 C UPAB: 20031216 NOVELTY - Component made from a titanium aluminide material produced by reaction sintering in a powder metallurgical method has oxygen as oxide of a further element formed by thermal treatment and/or during sintering embedded in the titanium aluminide material. The whole titanium aluminide material contains more than 0.1 wt.% oxygen. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a process for the powder metallurgy production of the above compone...

  4. Titanium Implant Osseointegration Problems with Alternate Solutions Using Epoxy/Carbon-Fiber-Reinforced Composite

    Directory of Open Access Journals (Sweden)

    Richard C. Petersen

    2014-12-01

    Full Text Available The aim of the article is to present recent developments in material research with bisphenyl-polymer/carbon-fiber-reinforced composite that have produced highly influential results toward improving upon current titanium bone implant clinical osseointegration success. Titanium is now the standard intra-oral tooth root/bone implant material with biocompatible interface relationships that confer potential osseointegration. Titanium produces a TiO2 oxide surface layer reactively that can provide chemical bonding through various electron interactions as a possible explanation for biocompatibility. Nevertheless, titanium alloy implants produce corrosion particles and fail by mechanisms generally related to surface interaction on bone to promote an inflammation with fibrous aseptic loosening or infection that can require implant removal. Further, lowered oxygen concentrations from poor vasculature at a foreign metal surface interface promote a build-up of host-cell-related electrons as free radicals and proton acid that can encourage infection and inflammation to greatly influence implant failure. To provide improved osseointegration many different coating processes and alternate polymer matrix composite (PMC solutions have been considered that supply new designing potential to possibly overcome problems with titanium bone implants. Now for important consideration, PMCs have decisive biofunctional fabrication possibilities while maintaining mechanical properties from addition of high-strengthening varied fiber-reinforcement and complex fillers/additives to include hydroxyapatite or antimicrobial incorporation through thermoset polymers that cure at low temperatures. Topics/issues reviewed in this manuscript include titanium corrosion, implant infection, coatings and the new epoxy/carbon-fiber implant results discussing osseointegration with biocompatibility related to nonpolar molecular attractions with secondary bonding, carbon fiber in vivo

  5. Titanium Implant Osseointegration Problems with Alternate Solutions Using Epoxy/Carbon-Fiber-Reinforced Composite.

    Science.gov (United States)

    Petersen, Richard C

    2014-12-01

    The aim of the article is to present recent developments in material research with bisphenyl-polymer/carbon-fiber-reinforced composite that have produced highly influential results toward improving upon current titanium bone implant clinical osseointegration success. Titanium is now the standard intra-oral tooth root/bone implant material with biocompatible interface relationships that confer potential osseointegration. Titanium produces a TiO 2 oxide surface layer reactively that can provide chemical bonding through various electron interactions as a possible explanation for biocompatibility. Nevertheless, titanium alloy implants produce corrosion particles and fail by mechanisms generally related to surface interaction on bone to promote an inflammation with fibrous aseptic loosening or infection that can require implant removal. Further, lowered oxygen concentrations from poor vasculature at a foreign metal surface interface promote a build-up of host-cell-related electrons as free radicals and proton acid that can encourage infection and inflammation to greatly influence implant failure. To provide improved osseointegration many different coating processes and alternate polymer matrix composite (PMC) solutions have been considered that supply new designing potential to possibly overcome problems with titanium bone implants. Now for important consideration, PMCs have decisive biofunctional fabrication possibilities while maintaining mechanical properties from addition of high-strengthening varied fiber-reinforcement and complex fillers/additives to include hydroxyapatite or antimicrobial incorporation through thermoset polymers that cure at low temperatures. Topics/issues reviewed in this manuscript include titanium corrosion, implant infection, coatings and the new epoxy/carbon-fiber implant results discussing osseointegration with biocompatibility related to nonpolar molecular attractions with secondary bonding, carbon fiber in vivo properties, electrical

  6. Fatigue Behavior of a Functionally-Graded Titanium Matrix Composite

    National Research Council Canada - National Science Library

    Cunningham, Scott R

    2005-01-01

    Functionally-graded Titanium Matrix Composites are an attempt to utilize the high-strength properties of a titanium matrix composite with a monolithic alloy having the more practical machining qualities...

  7. Contact Stress Design Parameters for Titanium Bearings, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — In response to NASA 2015 SBIR Topic H4.02, Air-Lock proposes to define the maximum allowable contact stress for Titanium bearings. The modulus of Titanium is lower...

  8. Handbook of International Alloy Compositions and Designations. Volume 1. Titanium

    Science.gov (United States)

    1976-11-01

    Institute Nacional de Tecnica Aeroespacial , Madrid, Spain, plus the proposed Spanish designations for titanium alloys. Swedish References 31. Titanium...JISC, JIS: Japanese Industria Standards Committee, Agency of Industiial Science and Technology, Ministry of international Trade and Industry, 3

  9. Enhanced Performance Near Net Shape Titanium Alloys by Thermohydrogen Processing

    National Research Council Canada - National Science Library

    Froes, F

    2001-01-01

    ...), powder metallurgy and cast titanium alloys. Fundamental results have been obtained which can now be used to develop optimum THP steps to refine the microstructure and improve the mechanical properties of titanium alloys...

  10. Lifetime of titanium filament at constant current

    International Nuclear Information System (INIS)

    Chou, T.S.; Lanni, C.

    1981-01-01

    Titanium Sublimation Pump (TSP) represents the most efficient and the least expensive method to produce Ultra High Vacuum (UHV) in storage rings. In ISABELLE, a proton storage accelerator under construction at Brookhaven National Laboratory, for example, TSP provides a pumping speed for hydrogen of > 2 x 10 6 l/s. Due to the finite life of titanium filaments, new filaments have to be switched in before the end of filament burn out, to ensure smooth operation of the accelerator. Therefore, several operational modes that can be used to activate the TSP were studied. The constant current mode is a convenient way of maintaining constant evaporating rate by increasing the power input while the filament diameter decreases as titanium evaporates. The filaments used in this experiment were standard Varian 916-0024 filaments made of Ti 85%, Mo 15% alloy. During their lifetime at a constant current of 48 amperes, the evaporation rate rose to a maximum at about 10% of their life and then flattened out to a constant value, 0.25 g/hr. The maximum evaporation rate occurs coincidently with the recrystallization of 74% Ti 26% Mo 2 from microstructure crystalline at higher titanium concentration to macrostructure crystalline at lower titanium concentration. As the macrocrystal grows, the slip plane develops at the grain boundary resulting in high resistance at the slip plane which will eventually cause the filament burn out due to local heating

  11. The Use of Titanium in the Friction of Artificial Joints

    Directory of Open Access Journals (Sweden)

    Sheykin, S.Ye.

    2015-05-01

    Full Text Available The possibility of using titanium in the friction of artificial joints is studying. Tribological characteristics of the friction pair titanium-hirulen is researching. The technology of diamond-abrasive machining, polishing and gas thermal nitridation spherical heads of pure titanium implants for hip person are developed. It is proved the increases of titanium head hardness achieved by pre-grinding the surface layer structure after cold plastic deformation.

  12. Synthesis and characterization of nano silicon and titanium nitride ...

    Indian Academy of Sciences (India)

    Synthesis and characterization of nano silicon and titanium nitride powders using atmospheric microwave plasma technique ... nucleation of silicon vapour produced by the radial injection of silicon tetrachloride vapour and nano titanium nitride was synthesized by using liquid titanium tetrachloride as the precursor.

  13. Colloidal Plasmonic Titanium Nitride Nanoparticles: Properties and Applications

    DEFF Research Database (Denmark)

    Guler, Urcan; Suslov, Sergey; Kildishev, Alexander V.

    2015-01-01

    Optical properties of colloidal plasmonic titanium nitride nanoparticles are examined with an eye on their photothermal and photocatalytic applications via transmission electron microscopy and optical transmittance measurements. Single crystal titanium nitride cubic nanoparticles with an average...... degree of freedom for surface functionalization. The titanium oxide shell surrounding the plasmonic core can create new opportunities for photocatalytic applications....

  14. Applications of Titanium Dioxide Photocatalysis to Construction Materials

    CERN Document Server

    Ohama, Yoshihiko

    2011-01-01

    Titanium dioxide photocatalysis is based on the semiconducting nature of its anatase crystal type. Construction materials with titanium photocatalyst show performances of air purification, self-cleaning, water purification, antibacterial action. This book describes principles of titanium dioxide photocatalysis, its applications to cementitious and noncementitious materials, as well as an overview of standardization of testing methods.

  15. Synthesis and characterization of nano silicon and titanium nitride ...

    Indian Academy of Sciences (India)

    ... nano titanium nitride was synthesized by using liquid titanium tetrachloride as the precursor. The synthesized nano silicon and titanium nitride powders were characterized by XRD, XPS, TEM, SEM and BET. The characterization techniques indicated that the synthesized powders were indeed crystalline nanomaterials.

  16. Effects of thickness on electronic structure of titanium thin films

    Indian Academy of Sciences (India)

    Effects of thickness on the electronic structure of e-beam evaporated thin titanium films were studied using near-edge X-ray absorption fine structure (NEXAFS) technique at titanium 2,3 edge in total electron yield (TEY) mode and transmission yield mode. Thickness dependence of 2,3 branching ratio (BR) of titanium was ...

  17. 40 CFR 721.10021 - Magnesium potassium titanium oxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Magnesium potassium titanium oxide... Specific Chemical Substances § 721.10021 Magnesium potassium titanium oxide. (a) Chemical substance and... titanium oxide (PMN P-01-764; CAS No. 39290-90-9) is subject to reporting under this section for the...

  18. 40 CFR 721.10031 - Lithium potassium titanium oxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Lithium potassium titanium oxide. 721... Substances § 721.10031 Lithium potassium titanium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as lithium potassium titanium oxide (PMN P-02...

  19. Method for synthesis of titanium dioxide nanotubes using ionic liquids

    Science.gov (United States)

    Qu, Jun; Luo, Huimin; Dai, Sheng

    2013-11-19

    The invention is directed to a method for producing titanium dioxide nanotubes, the method comprising anodizing titanium metal in contact with an electrolytic medium containing an ionic liquid. The invention is also directed to the resulting titanium dioxide nanotubes, as well as devices incorporating the nanotubes, such as photovoltaic devices, hydrogen generation devices, and hydrogen detection devices.

  20. Array of titanium dioxide nanostructures for solar energy utilization

    Science.gov (United States)

    Qiu, Xiaofeng; Parans Paranthaman, Mariappan; Chi, Miaofang; Ivanov, Ilia N; Zhang, Zhenyu

    2014-12-30

    An array of titanium dioxide nanostructures for solar energy utilization includes a plurality of nanotubes, each nanotube including an outer layer coaxial with an inner layer, where the inner layer comprises p-type titanium dioxide and the outer layer comprises n-type titanium dioxide. An interface between the inner layer and the outer layer defines a p-n junction.

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

    Directory of Open Access Journals (Sweden)

    HAN Hai

    2005-11-01

    Full Text Available The development and research of casting titanium alloy and its casting technology, especially its application in aeronautical industry in China are presented. The technology of moulding, melting and casting of titanium alloy, casting quality control are introduced. The existing problem and development trend in titanium alloy casting technology are also discussed.

  2. Enhancing osseointegration using surface-modified titanium implants

    Science.gov (United States)

    Yang, Y.; Oh, N.; Liu, Y.; Chen, W.; Oh, S.; Appleford, M.; Kim, S.; Kim, K.; Park, S.; Bumgardner, J.; Haggard, W.; Ong, J.

    2006-07-01

    Osseointegrated dental implants are used to replace missing teeth. The success of implants is due to osseointegration or the direct contact of the implant surface and bone without a fibrous connective tissue interface. This review discusses the enhancement of osseointegration by means of anodized microporous titanium surfaces, functionally macroporous graded titanium coatings, nanoscale titanium surfaces, and different bioactive factors.

  3. Reaction of titanium polonides with carbon dioxide

    International Nuclear Information System (INIS)

    Abakumov, A.S.; Malyshev, M.L.; Reznikova, N.F.

    1987-01-01

    It has been ascertained that heating titanium and tantalum in carbon dioxide to temperatures of 500 or 800 0 C alters the composition of the gas phase, causing the advent of carbon monoxide and lowering the oxygen content. Investigation of the thermal stability of titanium polonides in a carbon dioxide medium has shown that titanium mono- and hemipolonides are decomposed at temperatures below 350 0 C. The temperature dependence of the vapor pressure of polonium produced in the decomposition of these polonides in a carbon dioxide medium have been determined by a radiotensimetric method. The enthalpy of the process, calculated from this relationship, is close to the enthalpy of vaporization of elementary polonium in vacuo

  4. Surface treatment for inducing nanotopography on titanium

    International Nuclear Information System (INIS)

    Oliveira, S.V. de; Ribeiro, A.A.; Oliveira, M.V. de

    2014-01-01

    The titanium implant surface plays extremely important role in the biological response. Therefore, the objective of this research was to study the titanium surface nanotopography modified by chemical treatment, in order to improve its bioactivity. Commercially pure titanium samples, ASTM F67 grade 2, were immersed in H 2 SO 4 /H 2 O 2 solution for 2 or 4 hours. The samples were characterized by Scanning Electron Microscopy, Scanning Confocal Optical Microscopy, X-ray Photoelectron Spectroscopy and Diffuse Reflectance Infrared Fourier Transform Spectroscopy. The results revealed nanostructured surfaces with TiO 2 layer, average roughness of 0.86 ± 0.06 μm and 1.07 ± 0.05 μm for 2 or 4 hours, respectively and nanopores with 18 ± 6.82 nm average diameter. (author)

  5. Stainless Steel to Titanium Bimetallic Transitions

    Energy Technology Data Exchange (ETDEWEB)

    Kaluzny, J. A. [Fermilab; Grimm, C. [Fermilab; Passarelli, D. [Fermilab

    2015-01-01

    In order to use stainless steel piping in an LCLS-II (Linac Coherent Light Source Upgrade) cryomodule, stainless steel to titanium bimetallic transitions are needed to connect the stainless steel piping to the titanium cavity helium vessel. Explosion bonded stainless steel to titanium transition pieces and bimetallic transition material samples have been tested. A sample transition tube was subjected to tests and x-ray examinations between tests. Samples of the bonded joint material were impact and tensile tested at room temperature as well as liquid helium temperature. The joint has been used successfully in horizontal tests of LCLS-II cavity helium vessels and is planned to be used in LCLS-II cryomodules. Results of material sample and transition tube tests will be presented.

  6. Effective removal of calcified deposits on microstructured titanium fixture surfaces of dental implants with erbium lasers.

    Science.gov (United States)

    Takagi, Toru; Aoki, Akira; Ichinose, Shizuko; Taniguchi, Yoichi; Tachikawa, Noriko; Shinoki, Takeshi; Meinzer, Walter; Sculean, Anton; Izumi, Yuichi

    2018-03-13

    Recently, the occurrence of peri-implantitis has been increasing. However, a suitable method to debride the contaminated surface of titanium implants has not been established. The aim of this study was to investigate the morphological changes of the microstructured fixture surface after erbium laser irradiation, and to clarify the effects of the erbium lasers when used to remove calcified deposits from implant fixture surfaces. In experiment 1, sandblasted, large grit, acid etched surface implants were treated with Er:YAG laser or Er,Cr:YSGG laser at 30-60 mJ/pulse and 20 Hz with water spray. In experiments 2 and 3, the effects of erbium lasers used to remove calcified deposits (artificially prepared deposits on virgin implants and natural calculus on failed implants) were investigated and compared with mechanical debridement using either a titanium curette or cotton pellets. After the various debridement methods, all specimens were analyzed by stereomicroscopy (SM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Stereomicroscopy and SEM showed that erbium lasers with optimal irradiation parameters did not have an effect on titanium microstructures. Compared to mechanical debridement, erbium lasers were more capable of removing calcified deposits on the microstructured surface without surface alteration using a non-contact sweeping irradiation at 40 mJ/pulse (ED 14.2 J/cm 2 /pulse) and 20 Hz with water spray. These results indicate that Er:YAG and Er,Cr:YSGG lasers are more advantageous in removing calcified deposits on the microstructured surface of titanium implants without inducing damage, compared to mechanical therapy by cotton pellet or titanium curette. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  7. Laser induced single spot oxidation of titanium

    Energy Technology Data Exchange (ETDEWEB)

    Jwad, Tahseen, E-mail: taj355@bham.ac.uk; Deng, Sunan; Butt, Haider; Dimov, S.

    2016-11-30

    Highlights: • A new high resolution laser induced oxidation (colouring) method is proposed (single spot oxidation). • The method is applied to control oxide films thicknesses and hence colours on titanium substrates in micro-scale. • The method enable imprinting high resolution coloured image on Ti substrate. • Optical and morphological periodic surface structures are also produced by an array of oxide spots using the proposed method. • Colour coding of two colours into one field is presented. - Abstract: Titanium oxides have a wide range of applications in industry, and they can be formed on pure titanium using different methods. Laser-induced oxidation is one of the most reliable methods due to its controllability and selectivity. Colour marking is one of the main applications of the oxidation process. However, the colourizing process based on laser scanning strategies is limited by the relative large processing area in comparison to the beam size. Single spot oxidation of titanium substrates is proposed in this research in order to increase the resolution of the processed area and also to address the requirements of potential new applications. The method is applied to produce oxide films with different thicknesses and hence colours on titanium substrates. High resolution colour image is imprinted on a sheet of pure titanium by converting its pixels’ colours into laser parameter settings. Optical and morphological periodic surface structures are also produced by an array of oxide spots and then analysed. Two colours have been coded into one field and the dependencies of the reflected colours on incident and azimuthal angles of the light are discussed. The findings are of interest to a range of application areas, as they can be used to imprint optical devices such as diffusers and Fresnel lenses on metallic surfaces as well as for colour marking.

  8. Laser induced single spot oxidation of titanium

    International Nuclear Information System (INIS)

    Jwad, Tahseen; Deng, Sunan; Butt, Haider; Dimov, S.

    2016-01-01

    Highlights: • A new high resolution laser induced oxidation (colouring) method is proposed (single spot oxidation). • The method is applied to control oxide films thicknesses and hence colours on titanium substrates in micro-scale. • The method enable imprinting high resolution coloured image on Ti substrate. • Optical and morphological periodic surface structures are also produced by an array of oxide spots using the proposed method. • Colour coding of two colours into one field is presented. - Abstract: Titanium oxides have a wide range of applications in industry, and they can be formed on pure titanium using different methods. Laser-induced oxidation is one of the most reliable methods due to its controllability and selectivity. Colour marking is one of the main applications of the oxidation process. However, the colourizing process based on laser scanning strategies is limited by the relative large processing area in comparison to the beam size. Single spot oxidation of titanium substrates is proposed in this research in order to increase the resolution of the processed area and also to address the requirements of potential new applications. The method is applied to produce oxide films with different thicknesses and hence colours on titanium substrates. High resolution colour image is imprinted on a sheet of pure titanium by converting its pixels’ colours into laser parameter settings. Optical and morphological periodic surface structures are also produced by an array of oxide spots and then analysed. Two colours have been coded into one field and the dependencies of the reflected colours on incident and azimuthal angles of the light are discussed. The findings are of interest to a range of application areas, as they can be used to imprint optical devices such as diffusers and Fresnel lenses on metallic surfaces as well as for colour marking.

  9. Bactericidal and antimicrobial effects of pure titanium and titanium alloy treated with short-term, low-energy UV irradiation.

    Science.gov (United States)

    Itabashi, T; Narita, K; Ono, A; Wada, K; Tanaka, T; Kumagai, G; Yamauchi, R; Nakane, A; Ishibashi, Y

    2017-02-01

    The surface of pure titanium (Ti) shows decreased histocompatibility over time; this phenomenon is known as biological ageing. UV irradiation enables the reversal of biological ageing through photofunctionalisation, a physicochemical alteration of the titanium surface. Ti implants are sterilised by UV irradiation in dental surgery. However, orthopaedic biomaterials are usually composed of the alloy Ti6Al4V, for which the antibacterial effects of UV irradiation are unconfirmed. Here we evaluated the bactericidal and antimicrobial effects of treating Ti and Ti6Al4V with UV irradiation of a lower and briefer dose than previously reported, for applications in implant surgery. Ti and Ti6Al4V disks were prepared. To evaluate the bactericidal effect of UV irradiation, Staphylococcus aureus 834 suspension was seeded onto the disks, which were then exposed to UV light for 15 minutes at a dose of 9 J/cm 2 . To evaluate the antimicrobial activity of UV irradiation, bacterial suspensions were seeded onto the disks 0, 0.5, one, six, 24 and 48 hours, and three and seven days after UV irradiation as described above. In both experiments, the bacteria were then harvested, cultured, and the number of colonies were counted. No colonies were observed when UV irradiation was performed after the bacteria were added to the disks. When the bacteria were seeded after UV irradiation, the amount of surviving bacteria on the Ti and Ti6Al4V disks decreased at 0 hours and then gradually increased. However, the antimicrobial activity was maintained for seven days after UV irradiation. Antimicrobial activity was induced for seven days after UV irradiation on both types of disk. Irradiated Ti6Al4V and Ti had similar antimicrobial properties. Cite this article: T. Itabashi, K. Narita, A. Ono, K. Wada, T. Tanaka, G. Kumagai, R. Yamauchi, A. Nakane, Y. Ishibashi. Bactericidal and antimicrobial effects of pure titanium and titanium alloy treated with short-term, low-energy UV irradiation. Bone Joint

  10. Creating mobile apps with Appcelerator Titanium

    CERN Document Server

    Brousseau, Christian

    2013-01-01

    Creating Mobile Apps with Appcelerator Titanium provides a hands-on approach and working examples on creating apps and games as well as embedding them onto a social networking website. Developers can then move on from there to develop their own applications based on the ones they have developed throughout the course of this book.""Creating Mobile Apps with Appcelerator Titanium"" is for developers who have experience with modern languages and development environments. Also, if you are familiar with the concepts of Object-oriented Programming (OOP), reusable components, AJAX closures, and so on

  11. Local heating with titanium nitride nanoparticles

    DEFF Research Database (Denmark)

    Guler, Urcan; Ndukaife, Justus C.; Naik, Gururaj V.

    2013-01-01

    We investigate the feasibility of titanium nitride (TiN) nanoparticles as local heat sources in the near infrared region, focusing on biological window. Experiments and simulations provide promising results for TiN, which is known to be bio-compatible.......We investigate the feasibility of titanium nitride (TiN) nanoparticles as local heat sources in the near infrared region, focusing on biological window. Experiments and simulations provide promising results for TiN, which is known to be bio-compatible....

  12. Titanium plate fixation of flail chest

    OpenAIRE

    Muhammad Nadeem; Hibbut-ur-Rauf Naseem; William F. Stendardi; Kathryn D. Bass

    2018-01-01

    Introduction: We present short and long term outcomes of titanium rib plating in two pediatric patients with traumatic flail chest. Cases: Patient 1 is a 12 year old male ATV driver with left thorax handlebar impalement with a flail segment of ribs 4–8. He was unable to wean from the ventilator by hospital day (HD) 4 and had titanium plating of ribs 4–7. He was extubated on postoperative day (POD) 1 and discharged home on POD 5. He returned to contact sports at 6 months. Patient 2 is a 13 ...

  13. Titanium catalyzed silicon nanowires and nanoplatelets

    Directory of Open Access Journals (Sweden)

    Mohammad A. U. Usman

    2013-03-01

    Full Text Available Silicon nanowires, nanoplatelets, and other morphologies resulted from silicon growth catalyzed by thin titanium layers. The nanowires have diameters down to 5 nm and lengths to tens of micrometers. The two-dimensional platelets, in some instances with filigreed, snow flake-like shapes, had thicknesses down to the 10 nm scale and spans to several micrometers. These platelets grew in a narrow temperature range around 900 celsius, apparently representing a new silicon crystallite morphology at this length scale. We surmise that the platelets grow with a faceted dendritic mechanism known for larger crystals nucleated by titanium silicide catalyst islands.

  14. Nickel and titanium nanoboride composite coating

    International Nuclear Information System (INIS)

    Efimova, K A; Galevsky, G V; Rudneva, V V; Kozyrev, N A; Orshanskaya, E G

    2015-01-01

    Electrodeposition conditions, structural-physical and mechanical properties (microhardness, cohesion with a base, wear resistance, corrosion currents) of electroplated composite coatings on the base of nickel with nano and micro-powders of titanium boride are investigated. It has been found out that electro-crystallization of nickel with boride nanoparticles is the cause of coating formation with structural fragments of small sizes, low porosity and improved physical and mechanical properties. Titanium nano-boride is a component of composite coating, as well as an effective modifier of nickel matrix. Nano-boride of the electrolyte improves efficiency of the latter due to increased permissible upper limit of the cathodic current density. (paper)

  15. The Properties of Titanium and Its Alloys

    OpenAIRE

    BIŠĆAN, VLATKA; LUETIĆ, VIKTORIJA

    2012-01-01

    Titanium metal is silver-grey color and high gloss, the ninth element of the abundance in the Earth’s crust, and can be found in meteorites. It has a low electrical conductivity and low coefficient of thermal expansion. Since titanium has a great passivity, its physical property is a high level of corrosion resistance to most mineral acids and chlorides. It has mechanical properties such as steel, has a high melting temperature and is light. Since it is highly resistant to corrosion it is app...

  16. IR and Near IR Laser Ablative Deposition of Amorphous Titanium Coats Containing Nanocrystalline Grains of Titanium and Titanium Suboxides.

    Czech Academy of Sciences Publication Activity Database

    Urbanová, M.; Pokorná, D.; Kupčík, Jaroslav; Medlín, R.; Křenek, T.; Pola, J.

    2014-01-01

    Roč. 67, NOV (2014), s. 237-244 ISSN 1350-4495 Institutional support: RVO:61388980 Keywords : laser ablation * laser deposition * amorphous titanium coats Subject RIV: CA - Inorganic Chemistry OBOR OECD: Inorganic and nuclear chemistry Impact factor: 1.550, year: 2014

  17. IR and Near IR Laser Ablative Deposition of Amorphous Titanium Coats Containing Nanocrystalline Grains of Titanium and Titanium Suboxides

    Czech Academy of Sciences Publication Activity Database

    Urbanová, Markéta; Pokorná, Dana; Kupčík, Jaroslav; Medlín, R.; Křenek, T.; Pola, Josef

    2014-01-01

    Roč. 67, NOV 2014 (2014), s. 237-244 ISSN 1350-4495 Grant - others:GA MŠMT(CZ) CZ.1.05/2.1.00/03.0088 Institutional support: RVO:67985858 Keywords : laser ablation * laser deposition * amorphous titanium coats Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.550, year: 2014

  18. In vitro biological outcome of laser application for modification or processing of titanium dental implants.

    Science.gov (United States)

    Hindy, Ahmed; Farahmand, Farzam; Tabatabaei, Fahimeh Sadat

    2017-07-01

    There are numerous functions for laser in modern implant dentistry including surface treatment, surface coating, and implant manufacturing. As laser application may potentially improve osseointegration of dental implants, we systematically reviewed the literature for in vitro biological responses to laser-modified or processed titanium dental implants. The literature was searched in PubMed, ISI Web, and Scopus, using keywords "titanium dental implants," "laser," "biocompatibility," and their synonyms. After screening the 136 references obtained, 28 articles met the inclusion criteria. We found that Nd:YAG laser was the most commonly used lasers in the treatment or processing of titanium dental implants. Most of the experiments used cell attachment and cell proliferation to investigate bioresponses of the implants. The most commonly used cells in these assays were osteoblast-like cells. Only one study was conducted in stem cells. These in vitro studies reported higher biocompatibility in laser-modified titanium implants. It seems that laser radiation plays a vital role in cell response to dental implants; however, it is necessary to accomplish more studies using different laser types and parameters on various cells to offer a more conclusive result.

  19. Development and Applications of Porous Tantalum Trabecular Metal Enhanced Titanium Dental Implants

    Science.gov (United States)

    Bencharit, Sompop; Byrd, Warren C.; Altarawneh, Sandra; Hosseini, Bashir; Leong, Austin; Reside, Glenn; Morelli, Thiago; Offenbacher, Steven

    2013-01-01

    Statement of Problem Porous tantalum trabecular metal has recently been incorporated in titanium dental implants as a new form of implant surface enhancement. However, there is little information on the applications of this material in implant dentistry. Methods We, therefore review the current literature on the basic science and clinical uses of this material. Results Porous tantalum metal is used to improve the contact between osseous structure and dental implants; and therefore presumably facilitate osseointegration. Success of porous tantalum metal in orthopedic implants led to the incorporation of porous tantalum metal in the design of root-from endosseous titanium implants. The porous tantalum three-dimensional enhancement of titanium dental implant surface allows for combining bone ongrowth together with bone ingrowth, or osseoincorporation. While little is known about the biological aspect of the porous tantalum in the oral cavity, there seems to be several possible advantages of this implant design. This article reviews the biological aspects of porous tantalum enhanced titanium dental implants, in particular the effects of anatomical consideration and oral environment to implant designs. Conclusions We propose here possible clinical situations and applications for this type of dental implant. Advantages and disadvantages of the implants as well as needed future clinical studies are discussed. PMID:23527899

  20. Use of hydrous titanium dioxide as potential sorbent for the removal of manganese from water

    Directory of Open Access Journals (Sweden)

    Ramakrishnan Kamaraj

    2014-12-01

    Full Text Available This research article deals with an electrosynthesis of hydrous titanium dioxide by anodic dissolution of titanium sacrificial anodes and their application for the adsorption of manganese from aqueous solution. Titanium sheet was used as the sacrificial anode and galvanized iron sheet was used as the cathode. The optimization of different experimental parameters like initial ion concentration, current density, pH, temperature, etc., on the removal efficiency of manganese was carried out. The maximum removal efficiency of 97.55 % was achieved at a current density of 0.08 A dm-2 and pH of 7.0. The Langmuir, Freundlich and Redlich Peterson isotherm models were applied to describe the equilibrium isotherms and the isotherm constants were determined. The adsorption of manganese preferably followed the Langmuir adsorption isotherm. The adsorption kinetics was modelled by first- and second- order rate models and the adsorption kinetic studies showed that the adsorption of manganese was best described using the second-order kinetic model. Thermodynamic parameters indicate that the adsorption of manganese on hydrous titanium dioxide was feasible, spontaneous and exothermic.

  1. Structure and properties of Titanium for dental implants

    Directory of Open Access Journals (Sweden)

    M. Greger

    2009-10-01

    Full Text Available This paper describes manufacture of nano-structural titanium, its structure and properties. Nano-titanium has higher specific strength properties than ordinary (coarse-grained titanium. Nano-titanium was produced by the equal-channel angular pressing (ETAP process. The research it self was focused on physical base of strengthening and softening processes and developments occurring at the grain boundaries during the ECAP process at half-hot temperature. Strength of nano-titanium varies around 960 MPa, grain size around 300 nm.

  2. Rapid PMR determination of hydrogen in titanium hydride and dehydrogenated titanium powders

    International Nuclear Information System (INIS)

    Il'enko, V.S.; Demidenko, L.M.

    1987-01-01

    Proton magnetic resonance (PMR) enables determining hydrogen quantitatively in titanium hydride and dehydrogenated titanium powders without destroying the specimen and is also more informative than high-temperature extraction methods. PMR provides data on the electron-nuclear interactions and the activation energies for hydrogen diffusion while also providing conclusions on the forms and positives of the hydrogen in the lattice and the binding to the metal atoms. The authors have developed a rapid method for determining hydrogen in titanium hydride and dehydrogenated titanium powders which reduces the analysis time and improves the metrological characteristics. The authors use a YaMR-5535 spectrometer working at 40 MHz upgraded for use with hydrogen in solids. The authors used specimens of mass about 2 g ground to 0.1 mm powder

  3. A case hardened component of titanium

    DEFF Research Database (Denmark)

    2017-01-01

    The present invention relates to a case hardened component of a titanium alloy, the component having a diffusion zone of a thickness of at least 50 μιτι, as calculated from the surface of the component, the diffusion zone comprising oxygen and carbon in solid solution and having a distinct phase...

  4. Carbon nanotube-based coatings on titanium

    Indian Academy of Sciences (India)

    Administrator

    1AGH University of Science and Technology, Faculty of Materials Science and Ceramics,. Mickiewicza Avenue 30, 30-059 Krakow, Poland. 2Silesian University of Technology, Faculty of Chemistry, B. Krzywoustego Street 6, 44-100 Gliwice, Poland. 3Medical ... the integration of titanium implant with bone tissue. There are a ...

  5. SYNTHESIS OF MESOPOROUS TITANIUM OXIDE AND ...

    African Journals Online (AJOL)

    The catalytic activity of Ru/m-TiO2 for methanol decomposition to carbon monoxide and hydrogen was investigated. It is found that synthesizing conditions of mesoporous materials affect the catalytic activity of Ru/m-TiO2. KEY WORDS: Mesoporous titanium oxide, Methanol decomposition, Ruthenium, Catalyst support, ...

  6. Bioactive borate glass coatings for titanium alloys.

    Science.gov (United States)

    Peddi, Laxmikanth; Brow, Richard K; Brown, Roger F

    2008-09-01

    Bioactive borate glass coatings have been developed for titanium and titanium alloys. Glasses from the Na(2)O-CaO-B(2)O(3) system, modified by additions of SiO(2), Al(2)O(3), and P(2)O(5), were characterized and compositions with thermal expansion matches to titanium were identified. Infrared and X-ray diffraction analyses indicate that a hydroxyapatite surface layer forms on the borate glasses after exposure to a simulated body fluid for 2 weeks at 37 degrees C; similar layers form on 45S5 Bioglass((R)) exposed to the same conditions. Assays with MC3T3-E1 pre-osteoblastic cells show the borate glasses exhibit in vitro biocompatibility similar to that of the 45S5 Bioglass((R)). An enameling technique was developed to form adherent borate glass coatings on Ti6Al4V alloy, with adhesive strengths of 36 +/- 2 MPa on polished substrates. The results show these new borate glasses to be promising candidates for forming bioactive coatings on titanium substrates.

  7. Titanium surgical implants processed by powder metallurgy

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, M.V. de [INT-DMCM, Inst. Nacional de Tecnologia, Rio de Janeiro, RJ (Brazil); Pereira, L.C. [Programa de Eng. de Materiais e Metalurgica, UFRJ-COPPE (Brazil); Schwanke, C.M.; Schaeffer, L. [Centro de Tecnologia- LdTM-INT-DMCM, UFRGS, Venezuela, CEP, Rio de Janeiro, RJ (Brazil)

    2001-07-01

    Due to their low density coupled with excellent corrosion resistance and good mechanical properties, titanium and titanium alloys have been widely used for surgical implants. They have also a relatively low young's modulus, allowing a good load transfer to the bone. The elastic modulus difference between metallic implant material and bone is large, which can lead to a fracture of the implant. To solve this problem, many implants for artificial joint and dental applications have been produced by powder metallurgy routes, obtaining a porous material with an even lower young's modulus than that of the bulk titanium. This porous structure allows bone ingrowth, as the osseous tissue invade the holes of the porous material while growing and adheres to it. Besides, near net shape technologies like powder metallurgy and injection molding techniques, can reduce the components high costs due to machining final steps, also providing a fine, uniform grain structure and lack of texture and segregation. This work outlines the characteristics, properties and some of the powder routes for producing titanium surgical implants and implant porous coatings. (orig.)

  8. Mesoporous titanium phosphates and related molecular sieves ...

    Indian Academy of Sciences (India)

    Unknown

    of reduction of carbon dioxide, a greenhouse gas. Synthesis of Ti-containing micro and mesoporous silica materials is also of outstanding interest because of their remarkable applicability to liquid phase partial oxidation13 reactions. However, the small pores of such highly active microporous titanium silicates (viz. TS-1 ...

  9. Titanium tungsten coatings for bioelectrochemical applications

    DEFF Research Database (Denmark)

    Wierzbicki, Rafal; Amato, Letizia; Łopacińska, J.

    2011-01-01

    This paper presents an assessment of titanium tungsten (TiW) coatings and their applicability as components of biosensing systems. The focus is put on using TiW as an electromechanical interface layer between carbon nanotube (CNT) forests and silicon nanograss (SiNG) cell scaffolds. Cytotoxicity...

  10. Titanium impregnated borosilicate zeolites for epoxidation catalysis

    Czech Academy of Sciences Publication Activity Database

    Přech, Jan; Vitvarová, Dana; Lupínková, Lenka; Kubů, Martin; Čejka, Jiří

    2015-01-01

    Roč. 212, AUG 2015 (2015), s. 28-34 ISSN 1387-1811 R&D Projects: GA ČR GAP106/11/0819 Institutional support: RVO:61388955 Keywords : borosilicate * titanium impregnation * epoxidation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.349, year: 2015

  11. Titanium Elastic Nails Successfully Splint Subsequent Femoral ...

    African Journals Online (AJOL)

    The current trend in the management of fractures in children with osteogenesis imperfecta (OI) is the use of expandable nails. These may not be widely available in resource- constrained settings. We report a case of a 9 year old female with a peri-prosthetic fracture treated with premeasured pre-contoured titanium elastic ...

  12. Thermochemically active iron titanium oxide materials

    Energy Technology Data Exchange (ETDEWEB)

    Coker, Eric Nicholas; Miller, James E.

    2018-01-16

    A thermal oxidation-reduction cycle is disclosed that uses iron titanium oxide as the reactive material. The cycle may be used for the thermal splitting of water and/or carbon dioxide to form hydrogen and/or carbon monoxide. The formed compounds may be used as syngas precursors to form fuels.

  13. Obtention of titanium and zirconium metallic

    International Nuclear Information System (INIS)

    Santos, P.R.G.; Rover, C.F.S.; Amaral, F.L.L.

    1988-01-01

    The development works of techniques and equipments for titanium and zirconium sponges obtention are mentioned. The Kroll Process used for the sponges production is described, consisting in the reduction of the metal tetracloride with magnesium in an inert atmosphere of helium or argon. (C.G.C.) [pt

  14. Evaluating the Johanson theory for titanium powder

    CSIR Research Space (South Africa)

    Chikosha, S

    2015-05-01

    Full Text Available . In this study, the Johanson theory was used to determine the rolling parameters of titanium powder. Preliminary results of the nip angle, nip pressures and maximum horizontal pressures of the mill for the powder rolled on a 55mm diameter roll with roll gap sizes...

  15. Super titanium blades for advanced steam turbines

    International Nuclear Information System (INIS)

    Coulon, P.A.

    1990-01-01

    In 1986, the Alsthom Steam Turbines Department launched the manufacture of large titanium alloy blades: airfoil length of 1360 mm and overall length of 1520 mm. These blades are designed for the last-stage low pressure blading of advanced steam turbines operating at full speed (3000 rpm) and rating between 300 and 800 MW. Using titanium alloys for steam turbine exhaust stages as substitutes for chrome steels, due to their high strength/density ratio and their almost complete resistance to corrosion, makes it possible to increase the length of blades significantly and correspondingly that steam passage section (by up to 50%) with a still conservative stresses level in the rotor. Alsthom relies on 8 years of experience in the field of titanium, since as early as 1979 large titanium blades (airfoil length of 1240 mm, overall length of 1430 mm) were erected for experimental purposes on the last stage of a 900 MW unit of the Dampierre-sur-Loire power plant and now totals 45,000 operating hours without problems. The paper summarizes the main properties (chemical, mechanical and structural) recorded on very large blades and is based in particular on numerous fatigue corrosion test results to justify the use of the Ti 6 Al 4 V alloy in a specific context of micrographic structure

  16. UV photofunctionalization promotes nano-biomimetic apatite deposition on titanium

    Science.gov (United States)

    Saita, Makiko; Ikeda, Takayuki; Yamada, Masahiro; Kimoto, Katsuhiko; Lee, Masaichi Chang-Il; Ogawa, Takahiro

    2016-01-01

    Background Although biomimetic apatite coating is a promising way to provide titanium with osteoconductivity, the efficiency and quality of deposition is often poor. Most titanium implants have microscale surface morphology, and an addition of nanoscale features while preserving the micromorphology may provide further biological benefit. Here, we examined the effect of ultraviolet (UV) light treatment of titanium, or photofunctionalization, on the efficacy of biomimetic apatite deposition on titanium and its biological capability. Methods and results Micro-roughed titanium disks were prepared by acid-etching with sulfuric acid. Micro-roughened disks with or without photofunctionalization (20-minute exposure to UV light) were immersed in simulated body fluid (SBF) for 1 or 5 days. Photofunctionalized titanium disks were superhydrophilic and did not form surface air bubbles when immersed in SBF, whereas non-photofunctionalized disks were hydrophobic and largely covered with air bubbles during immersion. An apatite-related signal was observed by X-ray diffraction on photofunctionalized titanium after 1 day of SBF immersion, which was equivalent to the one observed after 5 days of immersion of control titanium. Scanning electron microscopy revealed nodular apatite deposition in the valleys and at the inclines of micro-roughened structures without affecting the existing micro-configuration. Micro-roughened titanium and apatite-deposited titanium surfaces had similar roughness values. The attachment, spreading, settling, proliferation, and alkaline phosphate activity of bone marrow-derived osteoblasts were promoted on apatite-coated titanium with photofunctionalization. Conclusion UV-photofunctionalization of titanium enabled faster deposition of nanoscale biomimetic apatite, resulting in the improved biological capability compared to the similarly prepared apatite-deposited titanium without photofunctionalization. Photofunctionalization-assisted biomimetic apatite

  17. Magnesium-titanium alloys for biomedical applications

    Science.gov (United States)

    Hoffmann, Ilona

    Magnesium has been identified as a promising biodegradable implant material because it does not cause systemic toxicity and can reduce stress shielding. However, it corrodes too quickly in the body. Titanium, which is already used ubiquitously for implants, was chosen as the alloying element because of its proven biocompatibility and corrosion resistance in physiological environments. Thus, alloying magnesium with titanium is expected to improve the corrosion resistance of magnesium. Mg-Ti alloys with a titanium content ranging from 5 to 35 at.-% were successfully synthesized by mechanical alloying. Spark plasma sintering was identified as a processing route to consolidate the alloy powders made by ball-milling into bulk material without destroying the alloy structure. This is an important finding as this metastable Mg-Ti alloy can only be heated up to max. 200C° for a limited time without reaching the stable state of separated magnesium and titanium. The superior corrosion behavior of Mg 80-Ti20 alloy in a simulated physiological environment was shown through hydrogen evolution tests, where the corrosion rate was drastically reduced compared to pure magnesium and electrochemical measurements revealed an increased potential and resistance compared to pure magnesium. Cytotoxicity tests on murine pre-osteoblastic cells in vitro confirmed that supernatants made from Mg-Ti alloy were no more cytotoxic than supernatants prepared with pure magnesium. Mg and Mg-Ti alloys can also be used to make novel polymer-metal composites, e.g., with poly(lactic-co-glycolic acid) (PLGA) to avoid the polymer's detrimental pH drop during degradation and alter its degradation pattern. Thus, Mg-Ti alloys can be fabricated and consolidated while achieving improved corrosion resistance and maintaining cytocompatibility. This work opens up the possibility of using Mg-Ti alloys for fracture fixation implants and other biomedical applications. KEYWORDS: Magnesium, titanium, corrosion

  18. Machined Titanium Heat-Pipe Wick Structure

    Science.gov (United States)

    Rosenfeld, John H.; Minnerly, Kenneth G.; Gernert, Nelson J.

    2009-01-01

    Wick structures fabricated by machining of titanium porous material are essential components of lightweight titanium/ water heat pipes of a type now being developed for operation at temperatures up to 530 K in high-radiation environments. In the fabrication of some prior heat pipes, wicks have been made by extruding axial grooves into aluminum unfortunately, titanium cannot be extruded. In the fabrication of some other prior heat pipes, wicks have been made by in-situ sintering of metal powders shaped by the use of forming mandrels that are subsequently removed, but in the specific application that gave rise to the present fabrication method, the required dimensions and shapes of the heat-pipe structures would make it very difficult if not impossible to remove the mandrels due to the length and the small diameter. In the present method, a wick is made from one or more sections that are fabricated separately and assembled outside the tube that constitutes the outer heat pipe wall. The starting wick material is a slab of porous titanium material. This material is machined in its original flat configuration to form axial grooves. In addition, interlocking features are machined at the mating ends of short wick sections that are to be assembled to make a full-length continuous wick structure. Once the sections have been thus assembled, the resulting full-length flat wick structure is rolled into a cylindrical shape and inserted in the heatpipe tube (see figure). This wick-structure fabrication method is not limited to titanium/water heat pipes: It could be extended to other heat pipe materials and working fluids in which the wicks could be made from materials that could be pre-formed into porous slabs.

  19. Porous titanium bases for osteochondral tissue engineering

    Science.gov (United States)

    Nover, Adam B.; Lee, Stephanie L.; Georgescu, Maria S.; Howard, Daniel R.; Saunders, Reuben A.; Yu, William T.; Klein, Robert W.; Napolitano, Anthony P.; Ateshian, Gerard A.

    2015-01-01

    Tissue engineering of osteochondral grafts may offer a cell-based alternative to native allografts, which are in short supply. Previous studies promote the fabrication of grafts consisting of a viable cell-seeded hydrogel integrated atop a porous, bone-like metal. Advantages of the manufacturing process have led to the evaluation of porous titanium as the bone-like base material. Here, porous titanium was shown to support the growth of cartilage to produce native levels of Young’s modulus, using a clinically relevant cell source. Mechanical and biochemical properties were similar or higher for the osteochondral constructs compared to chondral-only controls. Further investigation into the mechanical influence of the base on the composite material suggests that underlying pores may decrease interstitial fluid pressurization and applied strains, which may be overcome by alterations to the base structure. Future studies aim to optimize titanium-based tissue engineered osteochondral constructs to best match the structural architecture and strength of native grafts. Statement of Significance The studies described in this manuscript follow up on previous studies from our lab pertaining to the fabrication of osteochondral grafts that consist of a bone-like porous metal and a chondrocyte-seeded hydrogel. Here, tissue engineered osteochondral grafts were cultured to native stiffness using adult chondrocytes, a clinically relevant cell source, and a porous titanium base, a material currently used in clinical implants. This porous titanium is manufactured via selective laser melting, offering the advantages of precise control over shape, pore size, and orientation. Additionally, this manuscript describes the mechanical influence of the porous base, which may have applicability to porous bases derived from other materials. PMID:26320541

  20. The Importance Of Surface Topography For The Biological Properties Of Nitrided Diffusion Layers Produced On Ti6Al4V Titanium Alloy

    Directory of Open Access Journals (Sweden)

    Wierzchoń T.

    2015-09-01

    Full Text Available Diffusion nitrided layers produced on titanium and its alloys are widely studied in terms of their application for cardiac and bone implants. The influence of the structure, the phase composition, topography and surface morphology on their biological properties is being investigated. The article presents the results of a study of the topography (nanotopography of the surface of TiN+Ti2N+αTi(N nitrided layers produced in low-temperature plasma on Ti6Al4V titanium alloy and their influence on the adhesion of blood platelets and their aggregates. The TEM microstructure of the produced layers have been examined and it was demonstrated that the interaction between platelets and the surface of the titanium implants subjected to glow-discharge nitriding can be shaped via modification of the roughness parameters of the external layer of the TiN titanium nitride nanocrystalline zone.

  1. Development of titanium alloys and surface treatments to increase the implants lifetime

    Directory of Open Access Journals (Sweden)

    Joan Lario-Femenía

    2016-12-01

    Full Text Available The population aging together with increase of life expectancy forces the development of new prosthesis which may present a higher useful life. The clinical success of implants is based on the osseointegration achievement. Therefore, metal implants must have a mechanical compatibility with the substituted bone, which is achieved through a combination of low elastic modulus, high flexural and fatigue strength. The improvement, in the short and long term, of the osseointegration depends on several factors, where the macroscopic design and dimensional, material and implant surface topography are of great importance. This article is focused on summarizing the advantages that present the titanium and its alloys to be used as biomaterials, and the development that they have suffered in recent decades to improve their biocompatibility. Consequently, the implants evolution has been recapitulated and summarized through three generations. In the recent years the interest on the surface treatments for metallic prostheses has been increased, the main objective is achieve a lasting integration between implant and bone tissue, in the shortest time possible. On this article various surface treatments currently used to modify the surface roughness or to obtain coatings are described it; it is worthy to mention the electrochemical oxidation with post-heat treated to modify the titanium oxide crystalline structure. After the literature review conducted for prepare this article, the ? titanium alloys, with a nanotubes surface of obtained by electrochemical oxidation and a subsequent step of heat treatment to obtain a crystalline structure are the future option to improve long term biocompatibility of titanium prostheses.

  2. Article

    African Journals Online (AJOL)

    2012-07-22

    Jul 22, 2012 ... Objectives. There are 19 physician anaesthesia training programmes within the 16 Southern Africa Development Community (SADC) region countries ... The postgraduate anaesthesia curricula currently used in countries such as .... Madagascar (French-speaking) have physician postgraduate programmes.

  3. ARTICLES

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    campbell

    The vulture is the most threatened group of birds in the world, and currently, 14 of 23 (61%) vulture species worldwide are threatened with extinction, and the most rapid declines have occurred in Asia and. Africa. (Sekercioglu. 2006,. Anderson. 2007,. BirdLife. International 2011, Ogada et al. 2011). Due to severe declines in.

  4. Article

    African Journals Online (AJOL)

    2012-07-28

    Jul 28, 2012 ... decision making, Honesty, Good clinical judgment, Communication skills and Carry out professional responsibilities. Interpersonal professionalism attributes were considered more important than intrapersonal or public professionalism. Conclusion. This study suggests that professionalism attributes are not.

  5. Article

    African Journals Online (AJOL)

    2012-12-03

    Dec 3, 2012 ... Three full-time permanent staff members manage the department between the two sites and additional part-time clinical supervisors are employed to assist .... An advantage of the e-learning platform is that it enables students to ... assessment and testing.3 Students at the University of Basel in Switzerland.

  6. Article

    African Journals Online (AJOL)

    Easy trade

    Keyword: academic library, ICT, learning, students, utilization, private university. Introduction. Information and communication technology (ICT) includes all internet-enabled infrastructures that are widely used .... utilization for achievement of goals because lack of ICT skills by users is part of the causes of negative attitude ...

  7. Article

    African Journals Online (AJOL)

    Essential characteristics of student professionalism are commitment, honesty, discretion, co-operation, participation, diligence and temperance. Students need to know how to deal with unprofessional behaviour, whether their own or other students' or teachers'. Medical schools must have comprehensive programmes for ...

  8. Article

    African Journals Online (AJOL)

    2012-12-02

    Dec 2, 2012 ... Thus, we argue that prohibition is a constitutional limitation, but does not necessarily achieve its purpose in the least repressive or most effective way. Finally, we suggest that a solution to the drug problem will have to address the health needs of the drug user and the context, particularly socio-economic, of ...

  9. Article

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    yinka

    value of an organization by treating the knowledge of organizational members as an asset similar to capital facilities, (U.S. Department ... generate the value of knowledge-based assets, an imperative of modern business”. Knowledge ..... emphasis on the balanced scorecard learning and growth perspective. Management,.

  10. ARTICLES

    African Journals Online (AJOL)

    Houston, and an anonymous referee, improved the manuscript considerably, and we thank them for helping us clarify our. findings. The first two authors were students at Sherbrooke University and conservation science intems at Hawk Mountain Sanctuary when the work was carried out. This is. Hawk Mountain Sanctuary ...

  11. Article

    African Journals Online (AJOL)

    2012-06-15

    Jun 15, 2012 ... cur in alternative forms such as through the use of written and audiovisual educational materials in appropriate languages, or over the telephone, both of which have .... The translation of US testing kits to the. South African context requires consideration of several issues. First, an appropriate test must detect ...

  12. Article

    African Journals Online (AJOL)

    2011-06-11

    Jun 11, 2011 ... intervention studies and it is unknown whether implementing these rec- ommendations would have an effect at all, and if so whether the magni- tude of the effect would warrant large-scale implementation of language training. Few intervention studies for HCWs and non-language-concordant patients have ...

  13. Article

    African Journals Online (AJOL)

    USER

    available. A study conducted by Chigbu and Dim (2012) on connectivity and accessibility in .... Marital status. Single. 85. 36.2. Married. 150. 63.8. Rank. Professors. 20. 8.5. Associate. Professors. 22. 9.4. Senior Lecturers. 40. 17.0. Lecturers I. 32. 13.6. Lecturers II ..... Lecturers level of satisfaction with availability of electronic.

  14. Article

    African Journals Online (AJOL)

    {Rommel}

    Apparently, among those subject areas does not include skills- oriented courses such as the Bachelor of Science in Industrial ... hard copy questions and an optical mark reader (OMR) compatible answer sheet. The latter in ... incorporate CAA into skills oriented subjects such as those that can be seen in. BSIT courses.

  15. Article

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    hp 2000 pc

    The study discovered that book piracy affects investment in publishing business; discourage creativity among Nigerians; increase unemployment in publishing sector; lowers profitability to publishing companies and revenue generation to government. The research recommends among others that publishing companies.

  16. Article

    African Journals Online (AJOL)

    Nelson Edewor

    media enabled students to access local and web contents of information needs globally. The findings revealed that ... (2013) opined that web 2.0 technology and its associated social networks have brought tremendous effects to ..... :Facet publishing. Mcloughlin, Dawn and Benn, Jill (2014) Reference 2.0: evolution of virtual.

  17. Article

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    wallow

    Universities in developed countries are benefitting more from Intellectual Property (IP) they create than those in ... that are patentable and copyrighted which industries can deploy into their production process. To achieve that .... results. It also repositioned the Intellectual Property Management Office (IPMO) to spearhead.

  18. Article

    African Journals Online (AJOL)

    Easy trade

    learning, video conferencing, etc (Otubelu, 2010). ICT is an essential ... as in work places will enhance social development. It is very important ... effective ICT use. This is indeed a pronounced problem in academic libraries, (Otubelu, 2010. Availability and Utilization of Information Communication Technology. Facilities in a ...

  19. Article

    African Journals Online (AJOL)

    hindrance to successful implementation is that the planning and financing of continuing education is occurring ... training are needed to overcome the challenges associated with interpreter- mediated consultations. ..... communication skills, emotional labour, stress-coping, and well-being among physicians. Archives, The ...

  20. Article

    African Journals Online (AJOL)

    2012-07-15

    . University Rotterdam. 2007. ISBN 978-0-620-38223-6. 15. Ghosh S, Pandya H. Implementation of integrated learning program in neurosciences during first year of traditional medical course: perception of student and faculty.

  1. articles

    African Journals Online (AJOL)

    denise

    2011-12-04

    Dec 4, 2011 ... speed, learning and memory, attention and working memory, speech and language, executive functioning ... verbal and visual memory are considered highly sensitive indicators of HAND. These episodic ... indicate that basic receptive (e.g. auditory comprehension) and expressive (e.g. repetition) language ...

  2. Article

    African Journals Online (AJOL)

    2011-06-29

    Jun 29, 2011 ... fault for which medical malpractice liability may be incurred will usually be negligence, it may in ... of negligence, they may assist in tempering the increasing litigation spiral. Adequate allocation of funding ... present is just a normalisation towards global trends, and whether the increase in litigation may be ...

  3. article

    African Journals Online (AJOL)

    ournal of Child He alth. The Western Cape Department of Health's Comprehensive Service. Plan (CSP) set out a blueprint for service reconfiguration in the public health ..... indication of the required bed complement in these new services; however, there ... complications of HIV disease and feeding/intestinal failure issues.

  4. Article

    African Journals Online (AJOL)

    from the secretariat databases at the WRO and WHCED under ethics clearance number M120147. Graphs and linear regression analyses were made with GraphPad Prism (Version 4, GraphPad. Software Inc., San Diego, CA, USA). Results. Wits Research Office (WRO). The secretariat for general research applications is in ...

  5. Article

    African Journals Online (AJOL)

    2013-05-15

    May 15, 2013 ... construct meaning about health policies and services.[14] This engagement with the health system requires students to face the .... between satisfaction with the learning environment and burnout of medical students.[22] The implication for elective design was clear – avoiding haphazard arrangements for ...

  6. ARTICLES

    African Journals Online (AJOL)

    tendency for the westernisation of our diet was noted, with the traditional low-fat, high-fibre diet being replaced by a hig~-fat, low-fibre diet. This of course is in agreement with the increasing urbanisation which the country is experiencing as part of its transition. In terms of micronutrients (Table 1), calcium and riboflavin intake ...

  7. Article

    African Journals Online (AJOL)

    Compensation for participation in research. This element contained 3 items that required the PGSs to explain and describe availability of compensation, medical treatment and the risks if injury occurred. The performance in all these 3 items was below average, with the highest score 13.75%. Category B. Comprehension of ...

  8. Article

    African Journals Online (AJOL)

    2012-12-02

    Dec 2, 2012 ... Research capacity development is a global issue that faces all health professionals as it aims to enhance a profession through providing evidence for intervention strategies and thus assist in improving the quality of the healthcare delivered. However, when it comes to identifying strategies to promote the ...

  9. Article

    African Journals Online (AJOL)

    2013-05-27

    May 27, 2013 ... are nine interdisciplinary classes, each with an academic staff member. Supervisors are also recruited from within the university to facilitate student learning in the schools. Most of the student health promotion projects are aligned with the Life Orientation (LO) curriculum of the. Western Cape Education ...

  10. articles

    African Journals Online (AJOL)

    musculoskeletal conditions, particularly lower back pain, as the leading cause of disability.6 People in jobs with high social and ethical responsibility, such as in the police force, the military and teaching, may be at particular risk for developing stress-related disorders.7 Among these disorders, depression, anxiety and post-.

  11. Article

    African Journals Online (AJOL)

    user

    Abstract. The study assessed resources and services of the Nigeria Arabic Language Village (NALV). Library, Ngala. Four objectives and four research questions guided the study. Survey research design was adopted. The target population of the study was 1,030, out of which, 206 was drawn as the sample for the study.

  12. Article

    African Journals Online (AJOL)

    2010-08-17

    Aug 17, 2010 ... innovations was to shift the teaching from the previous didactic method to the more student-focused method of ... discussions around the change in teaching strategy. Although all involved academic staff ... novation. Is temperament a key to the success of teaching innovation? JJ Blitz1, MR van Rooyen1, DA ...

  13. Articles

    African Journals Online (AJOL)

    Proteomic variation in Korean ginseng (Panax ginseng C.A. Meyer) isolates from different geographic regions · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. KiBeom Lee, KwanSoon Park, 1738-1745 ...

  14. Article

    African Journals Online (AJOL)

    outcomes in the domains of knowledge, skills and professional behaviour. The objective of the study was to determine the experiences of the fifth cohort of graduating students from a medical programme following curricular transformation. Curriculum evaluation is integral to curriculum development and implementation.

  15. ARTICLES

    African Journals Online (AJOL)

    Campbell Murn

    Traders identified the following traits ascribed to vulture remains: treatment of epilepsy, insanity, stroke, ease of delivery in women, spiritual protection against witches and witchcraft, evil spirits, good luck (during gambling, money doubling, competition, contest), to stimulate walking in infants, and to gain supernatural powers.

  16. Article

    African Journals Online (AJOL)

    FAMILY

    Abstract. This paper evaluated the collections of Ramat Library, University of Maiduguri, Ibrahim Musa. Library, Sir Kashim College of Education, and Ramat Polytechnic Library Maiduguri, in terms of availability of funds, currency, and quantity of the materials available for the benefit of all their users. Four objectives and four ...

  17. Article

    African Journals Online (AJOL)

    2013-05-09

    May 9, 2013 ... Background. In 2007, a Supervision Course in Undergraduate Clinical Supervision was developed at the Faculty of Medicine and Health Sciences at Stellenbosch University in South Africa. The target group was inter-professional clinical educators that are involved in student education on the.

  18. Article

    African Journals Online (AJOL)

    Physicians were asked how useful learning about specific topics would be to improve their communication with patients from different cultural or socioeconomic backgrounds. The self-report measures were examined using mean differences among specialities, gender, and correlation with years in clinical practice. Results.

  19. Article

    African Journals Online (AJOL)

    2011-06-11

    Jun 11, 2011 ... Spanish to HCWs in the USA has shown significant improvements in communication with Hispanic patients and in-patient satisfaction.11,12. Multifaceted interventions targeting staff-patient communication have been shown to improve patient satisfaction in emergency room settings in Australia.13 A study ...

  20. ARTICLES

    African Journals Online (AJOL)

    Campbell Murn

    Occasionally poisoned dogs using. Strychnine and then reportedly buried the carcasses. Many trees had been felled around the site and this may have contributed to their decline. More common in dry season. Respondent directed us to. Bungoma District. Hospital, sewage works and Kitale. Town to find HVs. Bungoma.

  1. Article

    African Journals Online (AJOL)

    Roland

    adopted a descriptive survey research design and used the stratified and simple random sampling techniques to ... advent of information technologies has led ... retrieve and evaluate information has. Information literacy skills as correlates of library user satisfaction among undergraduates in Nigeria. Information Impact:.

  2. Article

    African Journals Online (AJOL)

    Publicly Financed Research and Development Act (IPR Act)23 regulates intellectual property rights, patents and benefits that may be applicable to HBMs. In Brazil, the Comissao Nacional de Ethica em Pesquisa (Na- tional Commission for Research Ethics) (CONEP) is respon- sible for assessing ethical issues arising from ...

  3. articles

    African Journals Online (AJOL)

    Most people spend most of their awake hours at work.1 Work may generate emotional, mental and/or physical disturbances in many people, and the quality and nature of people's experience at work may therefore have major health implications. Demanding or frustrating work or an inability to cope with stressors at work can.

  4. Article

    African Journals Online (AJOL)

    USER

    The study investigated the need for professional assistance to users of information retrieval tools at the National Library of Nigeria, Enugu branch. A total of 38 (thirty-eight) users of the library were randomly selected and used for the study. It was found that most of the respondents. 18(47.3%) consulted the card catalogue ...

  5. Article

    African Journals Online (AJOL)

    Not licensed for children below 2 years, prescribed for child <3 months. Piroxicam. Not licensed for children <6 years, prescribed for children <5 months. Licensed for use only in children with chronic juvenile arthritis, used as antipyretic in children. Paracetamol. Not licensed for children <6 years, prescribed for children <3 ...

  6. Article

    African Journals Online (AJOL)

    user

    satisfactorily. Having basic computer skills is a significant strength of e-library users in the universities. Therefore, computer self-efficacy is required to effectively explore new information system effectively because information stored in e-libraries have become, “with search engines, in general, one of the major web services, ...

  7. Article

    African Journals Online (AJOL)

    user

    ICT deployments for a whole lot of its activities including that of libraries. Enormous. Influence of Users' ... in the educational administration, business education and higher education programs. Paraskeva, ... prior experience in the use of technology as an aid to teaching tended to use it in the classroom. Users‟ perceptions ...

  8. articles

    African Journals Online (AJOL)

    2011-09-03

    Sep 3, 2011 ... Sexual dissatisfaction was assessed with one item, 'How satisfied are you with ... Depression. We assessed depressive symptoms using the 10-item version of the. Centres for Epidemiologic Studies Depression Scale (CES-D).17 The .... social support, lack of quality of life and low depressive symptoms.

  9. articles

    African Journals Online (AJOL)

    cut-off point of binge drinking for women (4 units) was reduced by one unit compared with men (5 units), as recommended by. Freeborn et al.29 Responses to items on the AUDIT are rated on a. 4-point Likert scale from 0 to 4, for a maximum score of 40 points. Higher AUDIT scores indicate more severe levels of risk; scores ...

  10. ARTICLES

    African Journals Online (AJOL)

    vigorous search for and treatment of maxillary sinusitis in nasotracheally intubated patients improves mortality.l'. One cause of conflict in the ICU is the persistently septic abdomen following rupture of a viscus, surgery or trauma. It is essential to be aware of the fact that the critically ill patient, who is often sedated and on ...

  11. Article

    African Journals Online (AJOL)

    homes and in the workplace. The continuous threat dominates the core of their existence, ... HIV testing of rape perpetrators.2,3 The Minister of Women, Chil- dren and Persons with Disabilities, Noluthando ..... treatment, which amounts to discrimination against this category of prisoner. There is also the moral dilemma of ...

  12. Article

    African Journals Online (AJOL)

    wallow

    Scope of the study. This study covered universities in South-west, Nigeria and six cadres of the lecturers. (from professor to assistant lecturers) in the selected universities. Seven IP: copyrights, performers' right, trademarks, patents, geographic indications, industrial design and trade secrets were the main focus of the study.

  13. Article

    African Journals Online (AJOL)

    2009-06-22

    including Justice Edwin Cameron of the Supreme. Court of Appeal of South Africa) have advocated a policy of routine. 'opt-out' HIV testing which, in an antenatal care setting, would mean that pregnant women are tested unless ...

  14. Article

    African Journals Online (AJOL)

    2009-06-23

    Jun 23, 2009 ... The other theory that is often used in religious-based medical ethics is the principle of double effect. This states that while it is wrong to commit a bad act, a good act is good in itself. If a good act has unintended bad consequences, then the person perform- ing the act is not morally blameworthy for those ...

  15. Article

    African Journals Online (AJOL)

    2012-12-02

    Dec 2, 2012 ... decision making or even wholly patient-centred model. This shift is more obvious in the ... model of communal decision making, healthcare financing is also often communally based, due to a lack of .... Therefore many patients might not return to the hospital because of fear of rejection or embarrassment.

  16. Article

    African Journals Online (AJOL)

    of HIV/AIDS, child sexual abuse, teenage pregnancy and school drop-out rates in this country.9 The research ... on teenage pregnancies that many children in South Africa are engaging in sexual activities before the age of 16 ... ment while maintaining self-esteem and avoiding causing shame to him/herself.16. This stage is ...

  17. Article

    African Journals Online (AJOL)

    Consider, for example, the young woman who consulted a doctor.4 The patient's mother saw the doctor's wife socially a few days later. In the course of their conversation, the doctor's wife relayed information disclosed by the patient to the doctor during the ..... tients, she or the doctor could approach the relevant patient and,.

  18. Article

    African Journals Online (AJOL)

    2010-12-21

    Dec 21, 2010 ... At the meeting, participants jointly developed a Vision for Health OER Network in Africa,2 which envisions a network of African institutions that would harness OER to share know- ledge, address curriculum gaps, and build communities of practice around health care education. Following the meeting, OER ...

  19. articles

    African Journals Online (AJOL)

    2011-12-04

    Dec 4, 2011 ... between the legal and psychiatric professions is not as effective as ... legal profession. The American Academy of Psychiatry and the. Law also highlights this when it mentions in its ethical guidelines that psychiatry and law have each ..... on helping court professionals to be more knowledgeable about.

  20. ARTICLES

    African Journals Online (AJOL)

    Campbell Murn

    this species. Vultures sold in stalls had been killed using agricultural chemicals, shotguns, traps, and ground tobacco powder. Urgent and drastic conservation measures are needed to prevent further exploitation of critically endangered vultures in Nigeria and ... hunting, electrocution and collision, disturbance, and ...

  1. articles

    African Journals Online (AJOL)

    2011-09-03

    Sep 3, 2011 ... to assess perceived social support,20 as used by Simbayi et al.21 The items were selected to reflect perceived tangible and emotional support. The Cronbach α-reliability coefficient of this 3-item scale was 0.92 in this sample. Internalised AIDS stigma. We used the 6-item internalised AIDS-related stigma ...

  2. Article

    African Journals Online (AJOL)

    MRS VIOLET IKOLO

    revealed that the teacher librarian have high level of job satisfaction. Also, Jeyara (2017) observed that 40% of teacher librarians were not satisfied with the whole facets related to their jobs. Pay is of importance in the discussion of the aspects of job satisfaction. Eva (2009) rated salary as one of the most satisfying aspects of ...

  3. ARTICLES

    African Journals Online (AJOL)

    Iron deficiency anaemia is a global public health problem as compelling and harmful as epidemics of ... death. Mental and motor development is impaired in anaemic infants and children and apathy, inactivity and .... use processed foods such as noodles, breakfast cereals and.soup cubes as vehicles for iron. Weaning foods ...

  4. ARTICLE

    African Journals Online (AJOL)

    With permission we tape—recorded some of these sessions, transcribed the recordings on to paper and analysed the results by sifting out common themes of the FGDs. FINDINGS. The FGDs in the schools revealed several perceived obstacles to an effective health education schistosomiasis control programme in the area.

  5. Article

    African Journals Online (AJOL)

    2012-12-04

    Dec 4, 2012 ... Corresponding author: G W Jones (gjones@cvh.on.ca). Objectives. Inadequate training of investigators in statistics and research methods in Africa contributes to having limited local evidence and infrastructure to support multi-centre international trials. Methods of teaching junior oncology professionals ...

  6. Article

    African Journals Online (AJOL)

    2011-06-04

    Jun 4, 2011 ... research has focused on the relationship between the health care profes- sional and the patient.4,5 At least one study has ... meaningful group or ''social network'' or to signal (that one is playing) a socially meaningful role'. ... among students of similar academic backgrounds. Objective: The aim of this study ...

  7. Article

    African Journals Online (AJOL)

    BODE OLAJIDE

    resources on the academic performance of the undergraduates of Federal University Oye-Ekiti, (FUOYE), Nigeria. This research is a survey. The population for this study includes the final year students of faculties of Social Science, Humanities and ...

  8. Article

    African Journals Online (AJOL)

    2012-06-27

    Jun 27, 2012 ... Kollapen stated that specific expenses in respect of the surrogate mother should be motivated in the agreement, as a danger exists that 'generic payments for expenditure without specificity may well run the risk of disguising the payment of compensation'.32 Full de- tails regarding the agency that facilitates ...

  9. Article

    African Journals Online (AJOL)

    2012-12-01

    Dec 1, 2012 ... Corresponding author: D Pretorius (deodanda@andurihl.com). Four years ago, the US Food and Drug Administration (FDA) ceased compliance with the Declaration of Helsinki (DoH) (2000 revision and all subsequent revisions) for conduct of clinical trials outside its borders. It instead ruled that compliance ...

  10. Article

    African Journals Online (AJOL)

    2009-06-12

    Jun 12, 2009 ... sexual intercourse. What is not clear, however, is whether gametes outside the human body may only be used for medical or dental purposes, or whether this section only .... has been expressed regarding the role of the presumptions in ..... ticulates it as follows in National Coalition for Gay and Lesbian.

  11. Article

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    USER

    health issues with their young children. Adolescents need such information else they go in search in books and electronics. Some even ask friends as some ladies experience their first menstruation in school. The arrival and proliferation of electronic resources and digital libraries have already influenced and changed the ...

  12. Article

    African Journals Online (AJOL)

    GREATBENSON

    social media policy, low level of ICT literacy among librarians in public libraries are the major constraints to effective integration of social media. This study has not only provided empirical evidences on the readiness of librarians in public libraries towards integrating social media tools to library and information services but ...

  13. Article

    African Journals Online (AJOL)

    HP

    Abstract. The aim of the paper is to examine the level of awareness and use of social media in knowledge management practices in university libraries. The study is guided by three (3) objectives: to identify social media tools used in knowledge management (KM) practices; ascertain areas of knowledge management ...

  14. Article

    African Journals Online (AJOL)

    Nelson Edewor

    Abstract. The changing nature of library services and the advent of social media network technology have created emphasis on its usage in academic institutions. Librarians are using the latest social media technology in marketing their information products and services to the library patrons. The aim of this study is ...

  15. Article

    African Journals Online (AJOL)

    HOD

    Internet Driven Learning Society in Nigerian Universities. The paper investigated the popularity of internet services within the university community and its consequences in academic performance. The study showed that there is a great adverse effect in the areas of combining social and media exploration like Facebooking ...

  16. Article

    African Journals Online (AJOL)

    FUTLIB12

    Electronic resources are sources of information in digital formats that are accessed using computers or hand-held ... tools like computer, internet, electronic networks and CD-ROMs. Before now, computer has ... the effect of access and utilisation of electronic information resources on academic performance of postgraduate ...

  17. ARTICLES -

    African Journals Online (AJOL)

    transfer of resistant bacterial pathogens is increased. The emergence of resistant bacteria is, however, a global problem affecting not only nosocomial but also community-acquired infections. .... Quinolone or carbapenem plus aminoglycoside. • Carbapenem monotherapy. Potential additions to each regimen could be.

  18. Article

    African Journals Online (AJOL)

    2012-12-01

    Dec 1, 2012 ... It will also consider when, under the Consumer Protection Act, such clauses may be regarded as unfair, unreasonable or unjust contract terms, and when certain terms and conditions have to be drawn to consumers' attention. Common law position regarding hospital exclusion clauses that limit liability for.

  19. Article

    African Journals Online (AJOL)

    2011-06-18

    Jun 18, 2011 ... tomical lexicon the concept of unclaimed bodies, since these were viewed as the most acceptable source .... This, in turn, was further legitimised by the sentiment that those who have been looked after by .... This Act was amended in 1884 to extend the list of authorised people having lawful possession of a ...

  20. Article

    African Journals Online (AJOL)

    User

    library patrons on how to behave while in the library so as to minimize noise, and on how to use the library facilities so as to prolong the lifespan of ... and Sciences (TITS) and Panipat Institute of. Engineering and Technology (PIET) ..... own and know how to operate smartphones they find it easy and convenient to use the.