Sample records for haynes alloys

  1. Oxidation behaviors of porous Haynes 214 alloy at high temperatures

    Wang, Yan, E-mail: [School of Aeronautics and Astronautics, Central South University, Changsha 410083 (China); Liu, Yong, E-mail: [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Tang, Huiping, E-mail: [State Key Laboratory of Porous Metals Materials, Northwest Institute for Nonferrous Metal Research, Xi' an 710016 (China); Li, Weijie, E-mail: [Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong, NSW 2522 (Australia)


    The oxidation behaviors of porous Haynes 214 alloy at temperatures from 850 to 1000 °C were investigated. The porous alloys before and after the oxidation were examined by optical microscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) analyses, and X-ray photoelectron spectroscopy (XPS). The oxidation kinetics of the porous alloy approximately follows a parabolic rate law and exhibits two stages controlled by different oxidation courses. Complex oxide scales composed of Cr{sub 2}O{sub 3}, NiCr{sub 2}O{sub 4} and Al{sub 2}O{sub 3} are formed on the oxidized porous alloys, and the formation of Cr{sub 2}O{sub 3} on its outer layer is promoted with the oxidation proceeding. The rough surface as well as the micropores in the microstructures of the porous alloy caused by the manufacturing process provides fast diffusion paths for oxygen so as to affect the formation of the oxide layers. Both the maximum pore size and the permeability of the porous alloys decrease with the increase of oxidation temperature and exposure time, which may limit its applications. - Highlights: • Two-stage oxidation kinetics controlled by different oxidation courses is showed. • Oxide scale mainly consists of Cr{sub 2}O{sub 3}, NiCr{sub 2}O{sub 4} and Al{sub 2}O{sub 3}. • Rough surface and micropores lead to the formation of uneven oxide structure. • Content of Cr{sub 2}O{sub 3} in the outer layer of the scale increases with time at 1000 °C. • Maximum pore size and permeability decrease with increasing temperature and time.

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

    Fahrmann Michael G.


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

  3. Effects of long-term high temperature exposure on the microstructure of Haynes alloy 230

    Veverkova, J.; Strang, A.; Atkinson, H.V. [Leicester Univ. (United Kingdom). Dept. of Engineering; Marchant, G.R. [Siemens Industrial Turbomachinery Ltd., Lincoln (United Kingdom)


    Haynes Alloy 230 was specifically designed to have excellent long-term thermal stability and resistance to the precipitation of damaging phases. This paper describes in detail studies on the effects of long-term high temperature exposure on the hardness, microstructural changes and tensile properties of thermally exposed samples of Haynes Alloy 230. The samples from the 2mm thick sheet material have been investigated using X-Ray diffraction and advanced electron microscopy techniques (FEGSEM, TEM etc.). The evolution of the precipitating phases was monitored across a wide range of temperatures (from 500 C to 1170 C) and durations (from 24 hours up to 30000 hours) and several key phases have been identified. In addition to the primary W-rich carbide and the precipitation of Cr-rich M{sub 23}C{sub 6}, a new brittle phase/carbide was observed within the microstructure at the highest exposure temperatures (above 930 C). (orig.)

  4. Advances in Solid State Joining of Haynes 230 High Temperature Alloy

    Ding, R. Jeffrey; Schneider, Judy; Walker, Bryant


    The J-2X engine is being designed for NASA s new class of crew and launch vehicles, the Ares I and Ares V. The J-2X is a LOX/Hydrogen upper stage engine with 294,000 lbs of thrust and a minimum Isp of 448 seconds. As part of the design criteria to meet the performance requirements a large film-cooled nozzle extension is being designed to further expand the hot gases and increases the specific impulse. The nozzle extension is designed using Haynes 230, a nickel-chromium-tungsten-molybdenum superalloy. The alloy was selected for its high strength at elevated temperatures and resistance to hydrogen embrittlement. The nozzle extension is manufactured from Haynes 230 plate spun-forged to form the contour and chemically-milled pockets for weight reduction. Currently fusion welding is being evaluated for joining the panels which are then mechanically etched and thinned to required dimensions for the nozzle extension blank. This blank is then spun formed into the parabolic geometry required for the nozzle. After forming the nozzle extension, weight reduction pockets are chemically milled into the nozzle. Fusion welding of Haynes results in columnar grains which are prone to hot cracking during forming processes. This restricts the ability to use spin forging to produce the nozzle contour. Solid state joining processes are being pursued as an alternative process to produce a structure more amenable to spin forming. Solid state processes have been shown to produce a refined grain structure within the joint regions as illustrated in Figure 1. Solid state joining processes include friction stir welding (FSW) and a patented modification termed thermal stir welding (TSW). The configuration of TSWing utilizes an induction coil to preheat the material minimizing the burden on the weld tool extending its life. This provides the ability to precisely select and control the temperature. The work presented in this presentation investigates the feasibility of joining the Haynes 230

  5. Tensile and Creep-Rupture Evaluation of a New Heat of Haynes Alloy 25

    Shingledecker, J.P.; Glanton, D.B.; Martin, R.L.; Sparks, B.L.; Swindeman, R.W.


    From 1999 to 2006, a program was undertaken within the Materials Science and Technology Division, formerly the Metals and Ceramics Division, of Oak Ridge National Laboratory to characterize the tensile and creep-rupture properties of a newly produced heat of Haynes alloy 25 (L-605). Tensile properties from room temperature to 1100 C were evaluated for base material and welded joints aged up to 12,000 hours at 675 C. Creep and creep-rupture tests were conducted on base metal and cross-weldments from 650 to 950 C. Pressurized tubular creep tests were conducted to evaluate multiaxial creep-rupture response of the material. Over 800,000 hours of creep test data were generated during the test program with the longest rupture tests extending beyond 38,000 hours, and the longest creep-rate experiments exceeding 40,000 hours.

  6. Corrosion behavior of Haynes {sup registered} 230 {sup registered} nickel-based super-alloys for integrated coal gasification combined cycle syngas plants. A plant exposure study

    Lee, Sungkyu; Lee, Jieun; Kang, Suk-Hwan; Lee, Seung-Jong; Yun, Yongseung [Institute for Advanced Engineering (IAE), Gyeonggi-do (Korea, Republic of). Plant Engineering Center; Kim, Min Jung [Sungkyunkwan Univ, Gyeonggi-do (Korea, Republic of). Advanced Materials Technology Research Center


    The corrosion behavior of commercially available Haynes {sup registered} 230 {sup registered} nickel-based alloy samples was investigated by exposure to coal-gasifying integrated coal gasification combined cycle pilot plant facilities affiliated with the Institute for Advanced Engineering (2.005 MPa and 160-300 C). The morphological and microstructural analyses of the exposed samples were conducted using scanning electron microscopy and energy-dispersive X-ray spectroscopy analysis on the external surface of the recovered corrosion test samples to obtain information of the corrosion scale. These analyses based on the pre- and post-exposure corrosion test samples combined with thermodynamic Ellingham-Pourbaix stability diagrams provided preliminary insight into the mechanism of the observed corrosion behavior prevailing in the piping materials that connected the particulate removal unit and water scrubber of the integrated coal gasification combined cycle pilot plant. Uniform material wastage was observed after 46 hours of operation, and a preliminary corrosion mechanism was suggested: the observed material waste and corrosion behavior of the Haynes {sup registered} 230 {sup registered} nickel-based alloy samples cut off from the coal syngas integrated coal gasification combined cycle plant were explained by the formation of discontinuous (complex) oxide phases and subsequent chlorine-induced active oxidation under the predominantly reducing environment encountered. This contribution continues the already published studies of the Fe-Ni-Cr-Co alloy Haynes {sup registered} 556 {sup registered}.

  7. Computational Thermodynamic Modeling of Hot Corrosion of Alloys Haynes 242 and HastelloyTM N for Molten Salt Service in Advanced High Temperature Reactors

    V. Glazoff, Michael; Charit, Indrajt; Sabharwall, Piyush


    An evaluation of thermodynamic aspects of hot corrosion of the superalloys Haynes 242 and HastelloyTM N in the eutectic mixtures of KF and ZrF4 is carried out for development of Advanced High Temperature Reactor (AHTR). This work models the behavior of several superalloys, potential candidates for the AHTR, using computational thermodynamics tool (ThermoCalc), leading to the development of thermodynamic description of the molten salt eutectic mixtures, and on that basis, mechanistic prediction of hot corrosion. The results from these studies indicated that the principal mechanism of hot corrosion was associated with chromium leaching for all of the superalloys described above. However, HastelloyTM N displayed the best hot corrosion performance. This was not surprising given it was developed originally to withstand the harsh conditions of molten salt environment. However, the results obtained in this study provided confidence in the employed methods of computational thermodynamics and could be further used for future alloy design efforts. Finally, several potential solutions to mitigate hot corrosion were proposed for further exploration, including coating development and controlled scaling of intermediate compounds in the KF-ZrF4 system.

  8. Research on 16Mo3 (16M Steel Pipes Overlaid with Haynes Nicro625 Alloy Using MIG (131 Method / Badania Rur Ze Stali 16Mo3 (16M Napawanych Metodą MIG (131 Stopem Haynes Nicro625

    Golański G.


    Full Text Available The paper presents the research on the microstructure and mechanical properties of a pipe made of 16Mo3 steel, overlaid with superalloy based on Haynes NiCro625 nickel. The overlay weld was overlaid using the MIG (131 method. The performed macro - and microscopic tests have shown the correct structure of the overlay weld without any welding unconformities. The examined overlay weld was characterized by a dendritic structure of the primary crystals accumulating towards the heat removal. It has been proved that the content of iron in the surface zone does not exceed 7%, and the steel-superalloy joint shows the highest properties in comparison with the materials joined.

  9. Multiaxial Creep-Fatigue and Creep-Ratcheting Failures of Grade 91 and Haynes 230 Alloys Toward Addressing Design Issues of Gen IV Nuclear Power Plants

    Hassan, Tasnim [North Carolina State Univ., Raleigh, NC (United States); Lissenden, Cliff [Penn State Univ., University Park, PA (United States); Carroll, Laura [Idaho National Lab. (INL), Idaho Falls, ID (United States)


    The proposed research will develop systematic sets of uniaxial and multiaxial experimental data at a very high temperature (850-950°C) for Alloy 617. The loading histories to be prescribed in the experiments will induce creep-fatigue and creep-ratcheting failure mechanisms. These experimental responses will be scrutinized in order to quantify the influences of temperature and creep on fatigue and ratcheting failures. A unified constitutive model (UCM) will be developed and validated against these experimental responses. The improved UCM will be incorporated into the widely used finite element commercial software packages ANSYS. The modified ANSYS will be validated so that it can be used for evaluating the very high temperature ASME-NH design-by-analysis methodology for Alloy 617 and thereby addressing the ASME-NH design code issues.

  10. Dynamic strain aging in Haynes 282 superalloy

    Hörnqvist Magnus


    Full Text Available Haynes 282 is a newly introduced Ni-based superallony, developed to provide a combination of high-temperature mechanical properties, thermal stability and processability. The present contribution investigates the effect of dynamic strain aging (DSA on the deformation behaviour of Haynes 282 during monotonic and cyclic loading. It is shown that DSA (presumably related to carbon diffusion based on rough estimates of the activation energy completely dominates the development of the stress during cycling at intermediate temperatures, leading to extensive cyclic hardening and serrated yielding. However, no clear effects on the fatigue life or the resulting dislocation structure could be observed. The tensile properties were not severely affected, in spite of the presence of extensive serrated yielding, although a reduction in ductility was observed in the DSA temperature regime. During monotonic loading at lower strain rates indications of an additional DSA mechanism due to substitutional elements were observed.

  11. Temperature Dependent Cyclic Deformation Mechanisms in Haynes 188 Superalloy

    Rao, K. Bhanu Sankara; Castelli, Michael G.; Allen, Gorden P.; Ellis, John R.


    The cyclic deformation behavior of a wrought cobalt-base superalloy, Haynes 188, has been investigated over a range of temperatures between 25 and 1000 C under isothermal and in-phase thermomechanical fatigue (TMF) conditions. Constant mechanical strain rates (epsilon-dot) of 10(exp -3)/s and 10(exp -4)/s were examined with a fully reversed strain range of 0.8%. Particular attention was given to the effects of dynamic strain aging (DSA) on the stress-strain response and low cycle fatigue life. A correlation between cyclic deformation behavior and microstructural substructure was made through detailed transmission electron microscopy. Although DSA was found to occur over a wide temperature range between approximately 300 and 750 C the microstructural characteristics and the deformation mechanisms responsible for DSA varied considerably and were dependent upon temperature. In general, the operation of DSA processes led to a maximum of the cyclic stress amplitude at 650 C and was accompanied by pronounced planar slip, relatively high dislocation density, and the generation of stacking faults. DSA was evidenced through a combination of phenomena, including serrated yielding, an inverse dependence of the maximum cyclic hardening with epsilon-dot, and an instantaneous inverse epsilon-dot sensitivity verified by specialized epsilon-dot -change tests. The TMF cyclic hardening behavior of the alloy appeared to be dictated by the substructural changes occuring at the maximum temperature in the TMF cycle.

  12. Biaxial thermal creep of Inconel 617 and Haynes 230 at 850 and 950 °C

    Tung, Hsiao-Ming; Mo, Kun; Stubbins, James F.


    The biaxial thermal creep behavior of Inconel 617 and Haynes 230 at 850 and 950 °C was investigated. Biaxial stresses were generated using the pressurized tube technique. The detailed creep deformation and fracture mechanism have been studied. Creep curves for both alloys showed that tertiary creep accounts for a greater portion of the materials' life, while secondary creep only accounts for a small portion. Fractographic examinations of the two alloys indicated that nucleation, growth, and coalescence of creep voids are the dominant micro-mechanisms for creep fracture. At 850 °C, alloy 230 has better creep resistance than alloy 617. When subjected to the biaxial stress state, the creep rupture life of the two alloys was considerably reduced when compared to the results obtained by uniaxial tensile creep tests. The Monkman-Grant relation proves to be a promising method for estimating the long-term creep life for alloy 617, whereas alloy 230 does not follow the relation. This might be associated with the significant changes in the microstructure of alloy 230 at high temperatures.

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

    WANG; Chang-shui; GUO; Jun-kang


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

  14. Weldability of the superalloys Haynes 188 and Hastelloy X by Nd:YAG

    Graneix Jérémie


    Full Text Available The requirements for welded aircraft parts have become increasingly severe, especially in terms of the reproducibility of the geometry and metallurgical grade of the weld bead. Laser welding is a viable method of assembly to meet these new demands, because of automation, to replace the manual TIG welding process. The purpose of this study is to determine the weldability of Hastelloy X and Haynes 188 alloys by the butt welding process with a Nd:YAG laser. To identify the influential parameters of the welding process (laser power, feed rate, focal diameter and flow of gas while streamlining testing, an experimental design was established with the CORICO software using the graphic correlation method. The position of the focal point was fixed at 1/3 of the thickness of the sheet. The gas flow rate and the power of the beam have a major effect on the mechanical properties and geometry of the weld. The strength of the weld is comparable to that of the base metal. However, there is a significant decrease in the elongation at break of approximately 30%. The first observations of the cross section of the weld by scanning electron microscopy coupled with EBSD analysis show a molten zone presenting dendritic large grains compared to the equiaxed grains of the base metals without a heat affected zone.

  15. Measurement and modeling of residual stress in a welded Haynes[reg] 25 cylinder

    Larsson, C. [Div. of Eng. Mat., Department of Mech. Eng., Linkoeping University, 58183 Linkoeping (Sweden)]. E-mail:; Holden, T.M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Bourke, M.A.M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Stout, M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Teague, J. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Lindgren, L.-E. [Div. Comp. Aided Design, Lulea University of Technology and Dalarna University, 97187 Lulea (Sweden)


    An experimental and simulation study of residual stresses was made in the vicinity of a gas tungsten arc weld, used to join a hemispherical end cap to a cylinder. The capped cylinder is used in a satellite application and was fabricated from a Co-based Haynes[reg] 25 alloy. The cylinder was 34.7 mm in outer diameter and 3.3 mm in thickness. The experimental measurements were made by neutron diffraction and the simulation used the implicit Marc finite element code. The experimental resolution was limited to approximately 3 mm parallel to the axis of the cylinder (the weld was 6 mm in the same direction) and comparison over the same volume of the finite element prediction showed general agreement. Subject to the limited spatial resolution, the largest experimentally measured tensile residual stress was 180 MPa, located at the middle of the weld. However, the predictions suggest that there are regions in the weld where average tensile residual stresses as much as 400 MPa exist. One qualitative disparity between the model and the experiments was that the measurement included a larger degree of asymmetry on either side of the weld than predicted by the model.

  16. An Alternate to Cobalt-Base Hardfacing Alloys

    Hickl, Anthony J.


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

  17. Oxidation of High-temperature Alloy Wires in Dry Oxygen and Water Vapor

    Opila, Elizabeth J.; Lorincz, Jonathan A.; DeMange, Jeffrey J.


    Small diameter wires (150 to 250 microns) of the high temperature alloys Haynes 188, Haynes 230, Haynes 230, Haynes 214, Kanthal Al and PM2000 were oxidized at 1204 C in dry oxygen or 50% H2O /50% O2 for 70 Hours. The oxidation kinetics were monitored using a thermogravimetric technique. Oxide phase composition and morphology of the oxidized wires were determined by X-ray diffraction,field emission scanning electron microscopy, and energy dispersive spectroscopy. The alumina-forming alloys, Kanthal Al and PM2000, out-performed the chromia-forming alloys under this conditions. PM2000 was recommended as the most promising candidate for advanced hybrid seal applications for space reentry control surface seals or hypersonic propulsion system seals. This study also demonstrated that thermogravimetric analysis of small diameter wires is a powerful technique for the study of oxide volatility, oxide adherence, and breakaway oxidation.

  18. Raise Your Voice: Leonard Haynes III Advocates for HBCUs in Washington

    Stuart, Reginald


    When Leonard Haynes III came to Washington in 1989 as an assistant secretary of education, the Southern University-trained historian found a national government marked by bipartisanship, collaboration and cooperation on a wide range of topics of importance to people of color in higher education. Today, the landscape and environment are "more…

  19. Influence of Yb:YAG Laser Beam Parameters on Haynes 188 Weld Fusion Zone Microstructure and Mechanical Properties

    Graneix, Jérémie; Beguin, Jean-Denis; Alexis, Joël; Masri, Talal


    The weldability of 1.2 mm thick Haynes 188 alloy sheets by a disk Yb:YAG laser welding was examined. Butt joints were made, and the influence of parameters such as power, size, and shape of the spot, welding speed, and gas flow has been investigated. Based on an iconographic correlation approach, optimum process parameters were determined. Depending on the distribution of the power density (circular or annular), acceptable welds were obtained. Powers greater than 1700 W, welding speeds higher than 3.8 m mm-1, and spot sizes between 160 and 320 μm were needed in the circular (small fiber) configuration. By comparison, the annular (large fiber) configuration required a power as high as 2500 W, and a welding speed less than 3.8 m min-1. The mechanical properties of the welds depended on their shape and microstructure, which in turn depended on the welding conditions. The content of carbides, the proportion of areas consisting of cellular and dendritic substructures, and the size of these substructures were used to explain the welded joint mechanical properties.

  20. Susceptibility to Hot Cracking and Weldment Heat Treatment of Haynes 230 Superalloy

    C.M.Cheng; C.P.Chou; I.K.Lee; I.C.Kuo


    This study investigates the susceptibility of hot cracking and weldment heat treatment of Haynes 230 superalloy.The Varestriant test was conducted to evaluate this susceptibility. Welding was performed by gas tungsten arc welding(GTAW)and plasma arc welding(PAW)with stress relief heat treatment and solid solution heat treatment. A tensile test is then performed to measure the changes in the mechanical properties of the heattreated material. The results indicate that the number of thermal cycles does not affect the susceptibility of Haynes 230 superalloy to hot cracking. However, it does increase the strain. In weldment of heat treatment,stress relief annealing increases the yield strength and tensile strength of the welded parts. The section of the tensile specimens shows fibrous fractures on the welded parts, regardless of whether they are heat-treated.

  1. Performance evaluation of several commercial alloys in a reducing environment

    Liu, Y.

    Several commercial alloys including Ebrite, Crofer 22 APU, Haynes 230 and Haynes 242, which are candidates for intermediate-temperature solid oxide fuel cell (SOFC) interconnect materials, were isothermally and cyclically oxidized at 900 °C in the reducing atmosphere of Ar + 5 vol.% H 2 + 3 vol.% H 2O corresponding to the SOFC anode environment. Results indicate that these alloys exhibited good scale spallation resistance with the Ni-base alloys possessing better oxidation resistance over the Fe-base alloys. Both Mn-Cr spinel and Cr 2O 3 were formed in the oxide scales of these alloys. For Crofer 22 APU and Haynes 242, a continuous protective MnO and Mn-Cr spinel layer formed outside on the inner layer of Cr 2O 3. The increase in scale ASR after longer-term thermal exposure in the reducing environment was relatively slower for the Ni-base alloys than for the Fe-base alloys.

  2. Alloy

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


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

  3. Distribution of transmissivity and yield of the surficial, Castle Hayne, and Peedee aquifers in Northern New Hanover County, North Carolina

    McSwain, Kristen Bukowski; Nagy, Laura A.


    Data were collected from more than 230 wells in northern New Hanover County, North Carolina, to evaluate the distribution of transmissivity and yield of the surficial, Castle Hayne, and Peedee aquifers of the Coastal Plain Physiographic Province. Constant-rate,single-well aquifer test data were obtained and analyzed to calculate additional transmissivity values for 25 production wells that were completed in the Castle Hayne or Peedee aquifer. In the surficial aquife, transmissivity values ranged from 400 to 12,700 feet squared per day, and reported yields ranged from 6 to 100 gallons per minute. In the Castle Hayne aquifer, transmissivity values ranged from 1,400 to 18,700 feet squared per day, and reported yields ranged from 9 to 640 gallons per minute. In the Peedee aquifer, transmissivity values ranged from 530 to 18,600 feet squared per day, and reported yields ranged from 8 to 1,000 gallons per minute.

  4. Mechanical Properties of Nb25Mo25Ta25W25 and V20Nb20Mo20Ta20W20 Refractory High Entropy Alloys (Postprint)


    temper ature from 548 MPa at 1000 C to 405 MPa at 1600 C (Table 2).ublic release; distribution unlimited. Table 4 Composition (in wt.%) of Inconel 718 ...values of the refractory HEAs are much higher than those of Haynes 230 at all studied temperatures and higher than those of Inconel 718 at...than twice (for the Nb25Mo25 Ta25W25 alloy) or four times (for the V20Nb20Mo20Ta20W20 alloy) higher than for Inconel 718 or Haynes 230 at 1000 C. The

  5. Towards the reform of medieval mendicant orders. Exhortatio ad meditationem et conformationem passionis Christi by Maciej Hayn (†1477

    Adam Poznański


    Full Text Available Exhortatio ad meditationem et conformationem passionis Christi written by a Dominican Matthias Hayn in 1470 describes how the friars should make an effort to improve their behaviour towards others and deepen their spiritual life during Lent. The author, who received good education while attending Dominican Studia Generalia in Cologne, Vienna and Paris, was designated by the Master General of the Order of Preachers to effect an observant reform in the Dominican Convent in Wrocław. Presumably Hayn wrote ‘Exhortatio’ as a part of his reform activities. The first part of the text is introduction, where Hayn explained the aim of his work. At the beginning he quoted the words from the first reading for Ash Wednesday: “return to me with all your heart, with fasting, with weeping, and with mourning” (Joel 2:12 and then he recommended to the brothers that these three acts of penance are the best way of reconciliation with God. According to Hayn the best example to follow in this matter is Christ, therefore during Lent the friars should ponder the Passion and seek to imitate Christ in their everyday situations, especially in those concerning life in monastery. The second part of Exhoratio (the main one is divided into forty three short chapters called “Morselli” and each of them consists of “Passio” and “Conformatio”. The first is a passage from the Passion parphrased by Hayn, the latter presents a commentary on the preceding “Passio” including advice for the friars.This article comprises a critical edition of Exhortatio ad meditationem et conformationem passionis Christi accompanied by a Polish translation. The edition is based on two exisiting copies of the text which are contained in two manuscripts from the Wrocław University Library collection.

  6. Multi-scale crack closure measurements with digital image correlation on Haynes 230

    Stefano Beretta


    Full Text Available An experimental campaign was developed to study fatigue crack growth in Haynes 230, a Ni-based superalloy. The effects of crack closure were investigated with digital image correlation, by applying two different approaches. Initially, full field regression algorithms were applied to extract the effective stress intensity factor ranges from the singular displacement field measured at crack tips. Local closure measurements were then performed by considering crack flanks relative displacements. Two points virtual extensometers were applied in this phase. Experimental results were then compared to the reference da/dN –ΔKeff curve: it was found that the correct estimation of crack opening levels shifts all the experimental points on the reference curve, showing that DIC can be successfully applied to measure crack closure effects.

  7. Joining of ceramic Ba0.5Sr0.5Co0.8Fe0.2O3 membranes for oxygen production to high temperature alloys

    Kiebach, Wolff-Ragnar; Engelbrecht, Kurt; Kwok, Kawai


    The possibility of joining dense ceramic BCSF tubular membranes to metal alloys using a silver braze was investigated. Four different alloys (Crofer 22 APU (R), Kanthal APM (R), Haynes 214 (R) and EN 1.4841) were considered and the influence of their oxide scale stability/reactivity and their the...

  8. Corrosion of refractory alloys induced by sodium sulphate in simulated low oxygen potential atmospheres of the BTL plants

    Couture, Ludovic [Grenoble Univ., Saint Martin d' Heres (France). SIMaP; IFP, Solaize (France). Materials Dept.; Galerie, Alain; Wouters, Yves [Grenoble Univ., Saint Martin d' Heres (France). SIMaP; Grosjean, Francois; Kittel, Jean; Ropital, Francois [IFP, Solaize (France). Materials Dept.


    BTL (biomass to liquid) is an innovative process to synthesize second generation bio-gasoline from wood and farm residues. In the present work, the effect of sodium sulphate on the high-temperature corrosion at 900 C of two refractory alloys, the chromia-forming Haynes {sup registered} HR-120 and the alumina-forming Haynes {sup registered} 214 in a simulated process atmosphere CO/H{sub 2}/CO{sub 2} (45/45/10% vol.), was investigated for durations up to 96 h. (orig.)

  9. Microstructural analysis of laser weld fusion zone in Haynes 282 superalloy

    Osoba, L.O. [Department of Mechanical and Manufacturing Engineering, University of Manitoba, Winnipeg, Manitoba, R3T 5V6 (Canada); Ding, R.G. [Department of Metallurgy and Materials Engineering, University of Birmingham, Birmingham B15 2TT (United Kingdom); Ojo, O.A., E-mail: [Department of Mechanical and Manufacturing Engineering, University of Manitoba, Winnipeg, Manitoba, R3T 5V6 (Canada)


    Analytical electron microscopy and spectroscopy analyses of the fusion zone (FZ) microstructure in autogenous laser beam welded Haynes 282 (HY 282) superalloy were performed. The micro-segregation patterns observed in the FZ indicate that Co, Cr and Al exhibited a nearly uniform distribution between the dendrite core and interdendritic regions while Ti and Mo were rejected into the interdendritic liquid during the weld solidification. Transmission electron diffraction analysis and energy dispersive X-ray microanalysis revealed the second phase particles formed along the FZ interdendritic region to be Ti-Mo rich MC-type carbide particles. Weld FZ solidification cracking, which is sometimes associated with the formation of {gamma}-{gamma}' eutectic in {gamma}' precipitation strengthened nickel-base superalloys, was not observed in the HY 282 superalloy. Modified primary solidification path due to carbon addition in the newly developed superalloy is used to explain preclusion of weld FZ solidification cracking in the material. - Highlights: Black-Right-Pointing-Pointer A newly developed superalloy was welded by CO{sub 2} laser beam joining technique. Black-Right-Pointing-Pointer Electron microscopy characterization of the weld microstructure was performed. Black-Right-Pointing-Pointer Identified interdendritic microconstituents consist of MC-type carbides. Black-Right-Pointing-Pointer Modification of primary solidification path is used to explain cracking resistance.

  10. Micromorphology of the floral nectary of red horse chestnut (Aesculus ×carnea Hayne

    Elżbieta Weryszko-Chmielewska


    Full Text Available In Europe Aesculus ×carnea Hayne is planted in cities as an avenue tree. Compared to A. hippocastanum L., it is more drought resistant, but less resistant to low temperatures. A. ×carnea is a lower tree than A. hippocastanum and develops a smaller corolla. It produces dark green, shiny and crinkled leaves. Its flowers have different colours, from bright pink to carmine red. The nectary glands secrete nectar abundantly. Due to the long corolla tube, nectar is difficult to reach for bees. The aim of this study was to investigate the topography and micromorphology of the nectaries of A. ×carnea using scanning electron microscopy. The study shows that the nectary gland of red horse chestnut forms an incomplete ring around the base of the staminal filaments, surrounding only four stamens out of the seven that occur in the flower. Three stamens are outside the nectary. In its widest place, the nectary diameter reaches 2.7 mm. Three expanded portions of the gland can bee seen in the marginal part of the nectary, adjoining the petals. The part of the nectary adjacent to the filaments forms a convex protrusion with a wavy appearance (shape, which results from the vicinity of the filaments. Nectar is secreted through numerous stomata located beneath the convex part of the nectary. The stoma length is 21.7 μm, while the width 23.3 μm. In the material examined, most stomata had open pores. Secretion was observed in many places. The stomata were surrounded by 6-7 guard cells; this allows them to be classified as the cyclocytic type. The cells of the stomatal complex were raised above the surface of the other epidermal cells. The walls of the guard cells and of the adjacent epidermal cells were covered by a cuticle with irregular striation.

  11. Time-Dependent Fatigue Crack Propagation Behavior of Two Solid-Solution-Strengthened Ni-Based Superalloys—INCONEL 617 and HAYNES 230

    Ma, Longzhou; Roy, Shawoon K.; Hasan, Muhammad H.; Pal, Joydeep; Chatterjee, Sudin


    The fatigue crack propagation (FCP) as well as the sustained loading crack growth (SLCG) behavior of two solid-solution-strengthened Ni-based superalloys, INCONEL 617 (Special Metals Corporation Family of Companies) and HAYNES 230 (Haynes International, Inc., Kokomo, IN), were studied at increased temperatures in laboratory air under a constant stress-intensity-factor ( K) condition. The crack propagation tests were conducted using a baseline cyclic triangular waveform with a frequency of 1/3 Hz. Various hold times were imposed at the maximum load of a fatigue cycle to study the hold time effect. The results show that a linear elastic fracture mechanics (LEFM) parameter, stress intensity factor ( K), is sufficient to describe the FCP and SLCG behavior at the testing temperatures ranging from 873 K to 1073 K (600 °C to 800 °C). As observed in the precipitation-strengthened superalloys, both INCONEL 617 and HAYNES 230 exhibited the time-dependent FCP, steady SLCG behavior, and existence of a damage zone ahead of crack tip. A thermodynamic equation was adapted to correlate the SLCG rates to determine thermal activation energy. The fracture modes associated with crack propagation behavior were discussed, and the mechanism of time-dependent FCP as well as SLCG was identified. Compared with INCONEL 617, the lower crack propagation rates of HAYNES 230 under the time-dependent condition were ascribed to the different fracture mode and the presence of numerous W-rich M6C-type and Cr-rich M23C6-type carbides. Toward the end, a phenomenological model was employed to correlate the FCP rates at cycle/time-dependent FCP domain. All the results suggest that an environmental factor, the stress assisted grain boundary oxygen embrittlement (SAGBOE) mechanism, is mainly responsible for the accelerated time-dependent FCP rates of INCONEL 617 and HAYNES 230.

  12. Inhibitive effects of some treatments on the browning rate during the in vitro culture of Acacia karroo Hayne

    Zhu Hong-lang; Janusz Zwolinski; Yin Wei-lun; Liu Yu-jun; Wang Hua-fang


    Acacia karroo Hayne is an arbor species widely distributed in South Africa with the characteristics of fast growth and drought resistance. The species was introduced to China recently. In vitro culture is an effective method to rapidly produce plants and a strategy to minimize somaclonal variation among regenerated plants. Browning, however, is a problem in establishing the in vitro culture system. The present study diminished the problem by selecting explants, using different browning inhibitors and chilling treatment. Results showed that the use of embryos as explants reduced the browning ratio to 46.7%, whilst stem segment explants were browned up to 56.7%. The adventitious buds were successfully induced in the modified tissue culture medium supplemented with 5.0 mg·L-1 6-BA and 0.1 mg·L-1 NAA. The proliferation coefficient of adventitious buds is 2.8.

  13. Effect of Bruchid Beetles (Burchidius Arabicus Decelle Infestation on the Germination of Acacia tortilis (Forssk. Hayne Seeds

    M. A.J. Ahmed


    Full Text Available The role of bruchid beetle infestation on seed germination of Acacia tortilis (Forssk. Hayne Mimosaceae under different incubation temperatures and degrees of scarification was studied under controlled conditions. Results indicate that seed germination was highest (96% in scarified seeds at 25-35°C incubation temperature, whereas, it was only 28% in intact seeds. Seeds infected by bruchid beetles with one or two holes did not germinate regardless of different incubation temperatures. X-ray results of A. tortilis seeds showed substantial consumption of endosperm and embryonic portions by the bruchid beetles resulting in one or two holes in the infected seeds curtailing seed germination. A unique method of identifying seed viability of A. tortilis by X-ray studies is reported. v

  14. Fatigue Crack Growth Behavior of Nickel-base Superalloy Haynes 282 at 550-750 °C

    Rozman, K. A.; Kruzic, J. J.; Hawk, J. A.


    The fatigue crack growth rates for nickel-based superalloy Haynes 282 were measured at temperatures of 550, 650, and 750 °C using compact tension specimens with a load ratio of 0.1 and cyclic loading frequencies of 25 Hz and 0.25 Hz. Increasing the temperature from 550 to 750 °C caused the fatigue crack growth rates to increase from ~20 to 60% depending upon the applied stress intensity level. The effect of reducing the applied loading frequency increased the fatigue crack growth rates from ~20 to 70%, also depending upon the applied stress intensity range. The crack path was observed to be transgranular for the temperatures and frequencies used during fatigue crack growth rate testing. At 750 °C, there were some indications of limited intergranular cracking excursions at both loading frequencies; however, the extent of intergranular crack growth was limited and the cause is not understood at this time.

  15. Scale formation on Ni-based alloys in simulated solid oxide fuel cell interconnect environments

    Ziomek-Moroz, Margaret; Cramer, Stephen D.; Holcomb, Gordon R.; Covino, Bernard S., Jr.; Bullard, Sophie J.; Singh, P. (PNNL); Windisch, C.F. (PNNL); Johnson, C.D. (NETL); Schaeffer, C. (National Energy Research Laboratory, Morgantown, WV)


    Recent publications suggest that the environment on the fuel side of the bi-polar stainless steel SOFC interconnects changes the oxidation behavior and morphology of the scale formed on the air side. The U.S. Department of Energy Albany Research Center (ARC), has examined the role of such exposure conditions on advanced nickel base alloys. Alloy formulations developed at ARC and commercial alloys were studied using X-ray diffraction (XRD) and Raman spectroscopy. The electrical property of oxide scales formed on selected alloys was determined in terms of areaspecific resistance (ASR). The corrosion behavior of ARC nickel-based alloys exposed to a dual environment of air/ H2 were compared to those of Crofer 22APU and Haynes 230.

  16. Biaxial thermal creep of Alloy 617 An Alloy 230 for VHTR applications

    Mo, Kun; Lv, Wei; Tung, Hsiao-Ming; Yun, Di; Miao, Yinbin; Lan, Kuan-Che; Stubbins, James F.


    In this study, we employed pressurized creep tubes to investigate the biaxial thermal creep behavior of Inconel 617 (alloy 617) and Haynes 230 (alloy 230). Both alloys are considered to he the primary candidate structural materials for very high-temperature reactors (VITITRs) due to their exceptional high-temperature mechanical properties. The current creep experiments were conducted at 900 degrees C for the effective stress range of 15-35 MPa. For both alloys, complete creep strain development with primary, secondary, and tertiary regimes was observed in all the studied conditions. Tertiary creep was found to he dominant over the entire creep lives of both alloys. With increasing applied creep stress, the fraction of the secondary creep regime decreases. The nucleation, diffusion, and coarsening of creep voids and carbides on grain boundaries were found to be the main reasons for the limited secondary regime and were also found to be the major causes of creep fracture. The creep curves computed using the adjusted creep equation of the form epsilon= cosh 1(1 rt) + P-sigma ntm agree well with the experimental results for both alloys at die temperatures of 850-950 degrees C.

  17. Hydrogeology, hydraulic characteristics, and water-quality conditions in the surficial, Castle Hayne and Peedee aquifers of the greater New Hanover County area, North Carolina, 2012-13

    McSwain, Kristen Bukowski; Gurley, Laura N.; Antolino, Dominick J.


    A major issue facing the greater New Hanover County, North Carolina, area is the increased demand for drinking water resources as a result of rapid growth. The principal sources of freshwater supply in the greater New Hanover County area are withdrawals of surface water from the Cape Fear River and groundwater from the underlying Castle Hayne and Peedee aquifers. Industrial, mining, irrigation, and aquaculture groundwater withdrawals increasingly compete with public-supply utilities for freshwater resources. Future population growth and economic expansion will require increased dependence on high-quality sources of fresh groundwater. An evaluation of the hydrogeology and water-quality conditions in the surficial, Castle Hayne, and Peedee aquifers was conducted in New Hanover, eastern Brunswick, and southern Pender Counties, North Carolina. A hydrogeologic framework was delineated by using a description of the geologic and hydrogeologic units that compose aquifers and their confining units. Current and historic water-level, water-quality, and water-isotope data were used to approximate the present boundary between freshwater and brackish water in the study area. Water-level data collected during August–September 2012 and March 2013 in the Castle Hayne aquifer show that recharge areas with the highest groundwater altitudes are located in central New Hanover County, and the lowest are located in a discharge area along the Atlantic Ocean. Between 1964 and 2012, groundwater levels in the Castle Hayne aquifer in central New Hanover County have rebounded by about 10 feet, but in the Pages Creek area groundwater levels declined in excess of 20 feet. In the Peedee aquifer, the August–September 2012 groundwater levels were affected by industrial withdrawals in north-central New Hanover County. Groundwater levels in the Peedee aquifer declined more than 20 feet between 1964 and 2012 in northeastern New Hanover County because of increased withdrawals. Vertical gradients

  18. Ontogênese, anatomia e ultra-estrutura dos nectários extraflorais de Hymenaea stigonocarpa Mart. ex Hayne (Fabaceae - Caesalpinioideae Ontogenesis, anatomy, and ultrastructure of Hymenaea stigonocarpa Mart. ex Hayne (Fabaceae - Caesalpinioideae extrafloral nectaries

    Élder Antônio Sousa Paiva


    Full Text Available O jatobá-do-cerrado (Hymenaea stigonocarpa Mart. ex Hayne apresenta nectários extraflorais (NEFs, os quais são descritos pela primeira vez no gênero. Neste trabalho foram estudadas a distribuição, ontogênese, estrutura e ultra-estrutura dos nectários extraflorais (NEFs. Amostras de folhas em várias fases de desenvolvimento foram coletadas, fixadas e processadas para estudos em microscopia de luz e eletrônica de transmissão e varredura, segundo técnicas convencionais. Testes histoquímicos foram empregados para determinar a natureza química da secreção. Os NEFs estão distribuídos por todo o limbo, sendo mais concentrados nos terços basal e médio de cada folíolo. Estes nectários são embutidos no mesofilo, apresentam tecido secretor envolvido por uma endoderme e são vascularizados por xilema e floema. A atividade secretora dos NEFs é limitada à fase juvenil da folha. Nas folhas mais velhas, os NEFs tornam-se não funcionais. O tecido secretor dos NEFs é formado a partir da protoderme, enquanto a endoderme tem origem no meristema fundamental. No tecido secretor de nectários funcionais as células apresentam citoplasma denso, núcleo volumoso, mitocôndrias, plastídios com sistema de membranas pouco desenvolvido, gotas de óleo dispersas no citosol, dictiossomos e segmentos de retículo endoplasmático liso. A secreção é liberada por meio de rupturas cuticulares e apresenta polissacarídeos e lipídios.Hymenaea stigonocarpa Mart. ex Hayne, known as "jatobá-do-cerrado" has extrafloral nectaries (EFNs, which are reported for the first time in Hymenaea genus. In this research the origin, distribution, structure, and ultrastructure of the EFNs were studied. Samples of leaflets at different developmental stages were collected, fixed and processed by standard methods for analyses at light and electronic microscopes; histochemical tests were employed to determine the nature of secretion products. EFNs are distributed all over

  19. Anatomia dos órgãos vegetativos de Hymenaea martiana Hayne (Caesalpinioideae-Fabaceae): espécie de uso medicinal em Caetité-BA

    Leite, K. R. B.; M. S. SILVA; Saba, M. D.


    p. 673-679 Hymenaea martiana Hayne (Fabaceae-Caesalpinioideae) apresenta grande valor na medicina popular em Caetité. A casca, entrecasca do caule e a resina, são utilizadas no tratamento de diversos males. Neste estudo são apresentadas a caracterização anatômica e histoquímica dos órgãos vegetativos. Amostras foram coletadas e processadas segundo técnicas usuais em anatomia vegetal e histoquímica. Todos os órgãos apresentam, em visão transversal, epiderme unisseriada e cavidades secretora...

  20. Anatomia dos órgãos vegetativos de Hymenaea martiana Hayne (Caesalpinioideae-Fabaceae): espécie de uso medicinal em Caetité-BA

    M. S. SILVA; Leite, K. R. B.; Saba, M. D.


    Hymenaea martiana Hayne (Fabaceae-Caesalpinioideae) apresenta grande valor na medicina popular em Caetité. A casca, entrecasca do caule e a resina, são utilizadas no tratamento de diversos males. Neste estudo são apresentadas a caracterização anatômica e histoquímica dos órgãos vegetativos. Amostras foram coletadas e processadas segundo técnicas usuais em anatomia vegetal e histoquímica. Todos os órgãos apresentam, em visão transversal, epiderme unisseriada e cavidades secretoras. Cutícula es...

  1. Cyclic Oxidation of High-Temperature Alloy Wires in Air

    Reigel, Marissa M.


    High-temperature alloy wires are proposed for use in seal applications for future re-useable space vehicles. These alloys offer the potential for improved wear resistance of the seals. The wires must withstand the high temperature environments the seals are subjected to as well as maintain their oxidation resistance during the heating and cooling cycles of vehicle re-entry. To model this, the wires were subjected to cyclic oxidation in stagnant air. of this layer formation is dependent on temperature. Slow growing oxides such as chromia and alumina are desirable. Once the oxide is formed it can prevent the metal from further reacting with its environment. Cyclic oxidation models the changes in temperature these wires will undergo in application. Cycling the temperature introduces thermal stresses which can cause the oxide layer to break off. Re-growth of the oxide layer consumes more metal and therefore reduces the properties and durability of the material. were used for cyclic oxidation testing. The baseline material, Haynes 188, has a Co base and is a chromia former while the other two alloys, Kanthal A1 and PM2000, both have a Fe base and are alumina formers. Haynes 188 and Kanthal A1 wires are 250 pm in diameter and PM2000 wires are 150 pm in diameter. The coiled wire has a total surface area of 3 to 5 sq cm. The wires were oxidized for 11 cycles at 1204 C, each cycle containing a 1 hour heating time and a minimum 20 minute cooling time. Weights were taken between cycles. After 11 cycles, one wire of each composition was removed for analysis. The other wire continued testing for 70 cycles. Post-test analysis includes X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) for phase identification and morphology.

  2. «I want to be a pop idol» Oscar Wilde tra parodia e reinvenzione glam in Velvet Goldmine di Todd Haynes

    Pierpaolo Martino


    Full Text Available Il presente studio analizza Velvet Goldmine un film del 1998 diretto da Todd Haynes al fine di indagare come il regista americano riesca ad evidenziare la centralità del glam (emerso in Gran Bretagna nei primi anni Settanta nella cultura contemporanea, ponendo un' enfasi specifica sull’aspetto che più di ogni altro aveva caratterizzato quell’esperienza, ossia la sovversione parodica dell' idea di mascolinità normativa nei decenni precedenti. Sul palco i 'glamsters' – ossia artisti quali Bolan, Bowie, Roxy Music, Glitter – erano in grado, utilizzando segni visivi quali trucco e abiti 'glitter' di costruire un’identità di genere ibrida che si poneva in netto contrasto con il machismo di molti musicisti degli anni Sessanta. Seguendo un approccio metodologico in cui studi culturali, studi letterari e neo-musicologia finiscono per dialogare tra loro, la presente indagine crea uno stretto rapporto tra Oscar Wilde e la cultura glam – un rapporto individuato dal regista sin dalle prime battute del film – ma che qui viene declinato in un senso più specifico, in base al quale l' intero film rappresenta una parodia o reinvenzione glam dell'intera epopea wildiana e in cui le immagini e gli aforismi wildiani sembrano interrogare con la loro complessità e la loro portata dissacrante il nostro presente.  The present essay analyses Velvet Goldmine a 1998 film directed by Todd Haynes, in order to investigate how the American director points to the relevance of glam (emerged in Great Britain at the beginning of the Seventies within contemporary culture, focusing on one of its most relevant aspects, that is the parodic subversion  of the normative idea of masculinity which was dominant in the previous decades. Glamsters – that is, such artists as Bolan, Bowie, Roxy Music and Glitter – were able, using such visual signs as make-up and glitter dresses, to construct a hybrid gender identity, which sharply contrasted with the normative

  3. Anatomia dos órgãos vegetativos de Hymenaea martiana Hayne (Caesalpinioideae-Fabaceae): espécie de uso medicinal em Caetité-BA Anatomy of vegetative organs of Hymenaea martiana Hayne (Fabaceae-Caesalpinioideae): a species of medicinal use in Caetité-Bahia State, Brazil

    M. S. SILVA; Leite, K. R. B.; Saba, M. D.


    Hymenaea martiana Hayne (Fabaceae-Caesalpinioideae) apresenta grande valor na medicina popular em Caetité. A casca, entrecasca do caule e a resina, são utilizadas no tratamento de diversos males. Neste estudo são apresentadas a caracterização anatômica e histoquímica dos órgãos vegetativos. Amostras foram coletadas e processadas segundo técnicas usuais em anatomia vegetal e histoquímica. Todos os órgãos apresentam, em visão transversal, epiderme unisseriada e cavidades secretoras. Cutícula es...

  4. Erosion-Corrosion of Iron and Nickel Alloys at Elevated Temperature in a Combustion Gas Environment

    Tylczak, Joseph [NETL


    This paper reports on the results of a study that compares the erosion-corrosion behavior of a variety of alloys (Fe- 2¼Cr 1Mo, 304 SS, 310 SS, Incoloy 800, Haynes 230 and a Fe3Al) in a combustion environment. Advanced coal combustion environments, with higher temperatures, are driving re-examination of traditional and examination of new alloys in these hostile environments. In order to simulate conditions in advanced coal combustion boilers, a special erosion apparatus was used to allow for impingement of particles under a low abrasive flux in a gaseous environment comprised of 20 % CO2, 0.05 % HCl, 77 % N2, 3 % O2, and 0.1 % SO2. Tests were conducted at room temperature and 700 °C with ~ 270 μm silica, using an impact velocity of 20 m/s in both air and the simulated combustion gas environment. The erosion-corrosion behavior was characterized by gravimetric measurements and by examination of the degraded surfaces optically and by scanning electron microscopy (SEM). At room temperature most of the alloys had similar loss rates. Not surprisingly, at 700 °C the lower chrome-iron alloy had a very high loss rate. The nickel alloys tended to have higher loss rates than the high chrome austenitic alloys.

  5. Crescimento de Hymenaea courbaril L. var. stilbocarpa (Hayne Lee et Lang. e Enterolobium contortisiliquum (Vell. Morong (Leguminosae sob diferentes níveis de sombreamento Growth of Hymenaea courbaril L. var. stilbocarpa (Hayne Lee et Lang. e Enterolobium contortisiliquum (Vell. Morong (Leguminosae under different shading levels

    Ana Lúcia da Silva Lima


    Full Text Available Hymenaea courbaril L. var. stilbocarpa (Hayne Lee et Lang. é uma espécie clímax tolerante a sombra, ao passo que Enterolobium contortisiliquum (Vell. Morong. é uma espécie pioneira. O desenvolvimento destas espécies pode refletir a habilidade de adaptação aos diferentes fatores ambientais (luz, água e temperatura no local em que estão crescendo. O suprimento inadequado de um desses fatores pode reduzir o vigor da planta e limitar seu desenvolvimento. O presente trabalho teve como objetivo avaliar os efeitos do nível de sombreamento no crescimento e a concentração de pigmentos fotossintéticos em duas espécies de leguminosas arbóreas, Hymenaea courbaril L. var. stilbocarpa (Hayne Lee et Lang. e Enterolobium contortisiliquum (Vell. Morong. O experimento foi conduzido no Setor de Olericultura do Centro Universitário Luterano de Ji-Paraná (CEULJI/ULBRA/Rondônia. Durante a formação das mudas, ambas as espécies foram expostas a quatro tratamentos de sombra: 0 % (controle - sol pleno; 30 %; 50 % e 80 %. Cada tratamento foi constituído com três repetições de cada espécie; o delineamento experimental foi inteiramente casualisado. Quatro meses após a semeadura, as seguintes análises foram realizadas: número de folhas, altura da planta, comprimento do sistema radicular, massa seca total e concentração de pigmentos fotossintéticos. O tratamento sob sol pleno afetou negativamente o crescimento de ambas as espécies. As mudas crescidas sob 50% e 80% apresentaram melhor desenvolvimento. Conforme o aumento do sombreamento houve um decréscimo na razão clorofila a/b e um aumento nas concentrações de clorofila total e carotenóides totais.Hymenaea courbaril L. var. stilbocarpa (Hayne Lee et Lang. is a clímax shadow tolerant specie and Enterolobium contortisiliquum (Vell. Morong., by the other hand, is considered as a pioneer specie. The development of these species may reflect its adaptation ability to different environmental

  6. Materials for Advanced Turbine Engines (MATE): Project 3: Design, fabrication and evaluation of an oxide dispersion strengthened sheet alloy combustor liner, volume 1

    Henricks, R. J.; Sheffler, K. D.


    The suitability of wrought oxide dispersion strengthened (ODS) superalloy sheet for gas turbine engine combustor applications was evaluated. Incoloy MA 956 (FeCrAl base) and Haynes Developmental Alloy (HDA) 8077 (NiCrAl base) were evaluated. Preliminary tests showed both alloys to be potentially viable combustor materials, with neither alloy exhibiting a significant advantage over the other. Both alloys demonstrated a +167C (300 F) advantage of creep and oxidation resistance with no improvement in thermal fatigue capability compared to a current generation combustor alloy (Hastelloy X). MA956 alloy was selected for further demonstration because it exhibited better manufacturing reproducibility than HDA8077. Additional property tests were conducted on MA956. To accommodate the limited thermal fatigue capability of ODS alloys, two segmented, mechanically attached, low strain ODS combustor design concepts having predicted fatigue lives or = 10,000 engine cycles were identified. One of these was a relatively conventional louvered geometry, while the other involved a transpiration cooled configuration. A series of 10,000 cycle combustor rig tests on subscale MA956 and Hastelloy X combustor components showed no cracking, thereby confirming the beneficial effect of the segmented design on thermal fatigue capability. These tests also confirmed the superior oxidation and thermal distortion resistance of the ODS alloy. A hybrid PW2037 inner burner liner containing MA956 and Hastelloy X components was designed and constructed.

  7. The Passive Film on Alloy 22

    Orme, C A


    This report describes oxide (passive film) formation on Alloy 22 surfaces when aged in air (25-750 C) and in solutions (90-110 C) over times ranging from days to 5 years. Most zero-valent metals (and their alloys) are thermodynamically unstable on the earth's surface and in its upper crust. Most will therefore convert to oxides when exposed to a surficial or underground environment. Despite the presence of thermodynamic driving forces, metals and their alloys may persist over lengthy timescales, even under normal atmospheric oxidizing conditions. One reason for this is that as metal is converted to metal oxide, the oxide forms a film on the surface that limits diffusion of chemical components between the environment and the metal. The formation of surface oxide is integral to understanding corrosion rates and processes for many of the more ''resistant'' metals and alloys. This report describes the correlation between oxide composition and oxide stability for Alloy 22 under a range of relevant repository environments. In the case in which the oxide itself is thermodynamically stable, the growth of the oxide film is a self-limiting process (i.e., as the film thickens, the diffusion across it slows, and the metal oxidizes at an ever-diminishing rate). In the case where the oxide is not thermodynamically stable, it dissolves at the oxide--solution interface as the metal oxidizes at the metal--oxide interface. The system achieves a steady state with a particular oxide thickness when the oxide dissolution and the metal oxidation rates are balanced. Once sufficient metal has transferred to solution, the solution may become saturated with respect to the oxide, which is then thermodynamically stable. The driving force for dissolution at the oxide--solution interface then ceases, and the first case is obtained. In the case of a complex alloy such as Alloy 22 (Haynes International 1997), the development and behavior of the oxide layer is complicated

  8. Aluminum alloy

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


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

  9. Microstructural Evolution and Creep-Rupture Behavior of Fusion Welds Involving Alloys for Advanced Ultrasupercritical Power Generation

    Bechetti, Daniel H., Jr.

    Projections for large increases in the global demand for electric power produced by the burning of fossil fuels, in combination with growing environmental concerns surrounding these fuel sources, have sparked initiatives in the United States, Europe, and Asia aimed at developing a new generation of coal fired power plant, termed Advanced Ultrasupercritical (A-USC). These plants are slated to operate at higher steam temperatures and pressures than current generation plants, and in so doing will offer increased process cycle efficiency and reduced greenhouse gas emissions. Several gamma' precipitation strengthened Ni-based superalloys have been identified as candidates for the hottest sections of these plants, but the microstructural instability and poor creep behavior (compared to wrought products) of fusion welds involving these alloys present significant hurdles to their implementation and a gap in knowledge that must be addressed. In this work, creep testing and in-depth microstructural characterization have been used to provide insight into the long-term performance of these alloys. First, an investigation of the weld metal microstructural evolution as it relates to creep strength reductions in A-USC alloys INCONELRTM 740, NIMONICRTM 263 (INCONEL and NIMONIC are registered trademarks of Special Metals Corporation), and HaynesRTM 282RTM (Haynes and 282 are registered trademarks of Haynes International) was performed. gamma'-precipitate free zones were identified in two of these three alloys, and their development was linked to the evolution of phases that precipitate at the expense of gamma'. Alloy 282 was shown to avoid precipitate free zone formation because the precipitates that form during long term aging in this alloy are poor in the gamma'-forming elements. Next, the microstructural evolution of INCONELRTM 740H (a compositional variant of alloy 740) during creep was investigated. Gleeble-based interrupted creep and creep-rupture testing was used to

  10. Optimization of headspace solid-phase microextraction for analysis of {beta}-caryophyllene in a nanoemulsion dosage form prepared with copaiba (Copaifera multijuga Hayne) oil

    Dias, Daiane de O; Colombo, Mariana; Kelmann, Regina G. [Programa de Pos-Graduacao em Ciencias Farmaceuticas, Faculdade de Farmacia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Av. Ipiranga, 2752, CEP 90610-000 (Brazil); De Souza, Tatiane P. [Programa de Pos-Graduacao em Ciencias Farmaceuticas, Universidade Federal do Amazonas, Manaus, Amazonas (Brazil); Bassani, Valquiria L.; Teixeira, Helder F. [Programa de Pos-Graduacao em Ciencias Farmaceuticas, Faculdade de Farmacia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Av. Ipiranga, 2752, CEP 90610-000 (Brazil); Veiga, Valdir F. [Departamento de Quimica, Instituto de Ciencias Exatas, UFAM, Av. Gal. Rodrigo Octavio, 6.200 - Japiim, 69.079-000, Manaus - AM (Brazil); Limberger, Renata P. [Programa de Pos-Graduacao em Ciencias Farmaceuticas, Faculdade de Farmacia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Av. Ipiranga, 2752, CEP 90610-000 (Brazil); and others


    Highlights: Black-Right-Pointing-Pointer A SPME-CG method is proposed for {beta}-caryophyllene assay in nanoemulsions containing copaiba oil. Black-Right-Pointing-Pointer SPME parameters were optimized for efficient {beta}-caryophyllene extraction. Black-Right-Pointing-Pointer The stability-indicating capability and specificity of the method were satisfied. Black-Right-Pointing-Pointer Nanoemulsions partially protected {beta}-caryophyllene under stressing conditions. Black-Right-Pointing-Pointer The proposed method presents linearity, lows LOD and LOQ, good precision, accuracy and robustness. - Abstract: Recent studies have shown the anti-inflammatory activity of Copaiba oils may be addressed to the high content of {beta}-caryophyllene, the most common sesquiterpene detected, especially in the Copaifera multijuga Hayne species. In the present study, nanoemulsions were proposed as a delivery system for copaiba oil in view to treat locally inflamed skin. This article describes the optimization and validation of a stability-indicating SPME-GC method, for {beta}-caryophyllene analysis in the nanoemulsions produced by high pressure homogenization. SPME methods are performed with PDMS (polydimethylsiloxane) fiber (100 {mu}m). Three SPME parameters were evaluated by a three-level-three-factor Box-Behnken factorial design as potentially affecting the technique efficiency. According to the results obtained, the best conditions to extract {beta}-caryophyllene were: (i) sampling temperature of 45 Degree-Sign C, (ii) sampling time of 20 min and (iii) no NaCl addition. Results coming from the forced degradation tests showed a reduction of {beta}-caryophyllene peak area when both caryophyllene methanolic solution and nanoemulsions were exposed to acid hydrolysis, UV-A irradiation, oxidative (H{sub 2}O{sub 2}) and thermolitic (60 Degree-Sign C) conditions. Such reduction occurred in lower extent in the nanoemulsions, suggesting a protective effect of the formulation to {beta

  11. Electrical Resistance Alloys and Low-Expansion Alloys

    Kjer, Torben


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

  12. Anatomia dos órgãos vegetativos de Hymenaea martiana Hayne (Caesalpinioideae-Fabaceae: espécie de uso medicinal em Caetité-BA Anatomy of vegetative organs of Hymenaea martiana Hayne (Fabaceae-Caesalpinioideae: a species of medicinal use in Caetité-Bahia State, Brazil

    M.S. Silva


    Full Text Available Hymenaea martiana Hayne (Fabaceae-Caesalpinioideae apresenta grande valor na medicina popular em Caetité. A casca, entrecasca do caule e a resina, são utilizadas no tratamento de diversos males. Neste estudo são apresentadas a caracterização anatômica e histoquímica dos órgãos vegetativos. Amostras foram coletadas e processadas segundo técnicas usuais em anatomia vegetal e histoquímica. Todos os órgãos apresentam, em visão transversal, epiderme unisseriada e cavidades secretoras. Cutícula espessa ocorre em todos os órgãos aéreos. A raiz é tetrarca. Colênquima lacunar foi encontrado no caule. Bainha de fibras esclerenquimáticas envolve os feixes vasculares dos órgãos aéreos. Células pétreas ocorrem no pecíolo. Tricomas tectores ocorrem em ambas as faces da folha. A folha é hipoestomática com estômatos paracíticos e o mesofilo é dorsiventral. Cristais de oxalato de cálcio ocorrem no caule, pecíolo e lâmina foliar. Compostos fenólicos ocorrem na raiz, pecíolo e nervura central da folha. Grãos de amido ocorrem na raiz, caule e pecíolo. Lipídios ocorrem em todos os órgãos. Acredita-se que compostos fenólicos e cavidades secretoras de resina podem justificar a utilidade medicinal da espécie pela população de Caetité.Hymenaea martiana Hayne (Fabaceae-Caesalpinioideae shows a great value in folk medicine in Caetité. Its bark, stem-bark and resin are used to treat various ailments. In this study, the anatomical and histochemical characterization of vegetative organs is reported. Samples were collected and processed according to usual techniques of plant anatomy and histochemistry. All organs have, by cross-sectional view, uniseriate epidermis and secretory cavities. Thick cuticle occurs in all aerial organs. The root is tetrarch. Lacunar collenchyma was found in the stem. Sclerenchymatic sheath of fibers surrounds the vascular bundles of the aerial organs. Stone cells occur in the petiole. Trichomes occur

  13. Avaliação in vitro da atividade antibacteriana de um cimento odontológico à base de óleo-resina de Copaifera multijuga Hayne In vitro assessment of antibacterial activity of a dental cement constituted of a Copaifera multijuga Hayne oil-resin

    Kátia Regina Felizardo Vasconcelos


    Full Text Available Um dos materiais utilizados para a adequação do meio bucal no serviço público é o cimento produzido a partir de óxido de zinco e eugenol. Entretanto, o eugenol é uma substância citotóxica que pode desencadear alguns efeitos adversos. Por essa razão, procura-se substituir o eugenol por uma substância que apresente baixa toxicidade, mantendo ou mesmo melhorando as propriedades do cimento. O óleo-resina de copaíba é um produto natural, utilizado pelas populações amazônicas e reconhecido por suas propriedades medicinais. Baseando-se nas propriedades desse óleo-resina, na ação antimicrobiana comprovada do hidróxido de cálcio e na ação anti-séptica do óxido de zinco, propôs-se formular um cimento odontológico obtido da associação do ZnO, Ca(OH2 e óleo-resina de Copaifera multijuga Hayne e avaliar sua atividade antibacteriana através do teste de diluição em meio líquido frente às cepas padrão de Streptococcus mutans (ATCC 25175 e S. sanguinis (ATCC 15300. Nesse ensaio, utilizaram-se os seguintes grupos experimentais: o cimento contendo ZnO, Ca(OH2 e óleo-resina de copaíba (G1 e cada um dos constituintes isoladamente, ZnO (G2, Ca(OH2 (G3 e óleo-resina de copaíba (G4. Todos os grupos analisados demonstraram atividade antibacteriana, o G4 apresentou os melhores resultados e o G1 mostrou-se um cimento promissor a ser utilizado em odontologia.One of the materials utilized for suitability of the oral means in the public service is the cement produced from zinc oxide and eugenol. However, eugenol is a cytotoxic substance that can trigger some adverse effects. For this reason, it is desired to replace eugenol for another substance that presents low toxicity, keeping or even improving the cement properties. The copaiba oil-resin is a natural product, utilized by the Amazonian population and recognized for its medicinal properties. Based on the properties of this oil-resin, on the proven antimicrobial activity of calcium

  14. Gallium suboxide vapor attack on chromium, cobalt, molybdenum, tungsten and their alloys at 1200 [degrees] C

    Kolman, D. G. (David G.); Taylor, T. N. (Thomas N.); Park, Y. (Youngsoo); Stan, M. (Marius); Butt, D. P. (Darryl P.); Maggiore, C. J. (Carl J.); Tesmer, Joseph R.; Havrilla, G. J. (George J.)


    Our prior work elucidated the failure mechanism of furnace materi als (304 SS, 316 SS, and Hastelloy C-276) exposed to gallium suboxide (Ga{sub 2}O) and/or gallium oxide (Ga{sub 2}O{sub 3}) during plutonium - gallium compound processing. Failure was hypothesized to result from concurrent alloy oxidation/Ga compound reduction followed by Ga uptake. The aim of the current work is to screen candidate replacement materials. Alloys Haynes 25 (49 Co - 20 Cr - 15 W - 10 Ni - 3 Fe - 2 Mn - 0.4 Si, wt%), 52 Mo - 48 Re (wt%), 62 W - 38 Cu (wt%), and commercially pure Cr, Co, Mo, W, and alumina were examined. Preliminary assessments of commercially pure W and Mo - Re suggest that these materials may be suitable for furnace construction. Thermodynamics calculations indicating that materials containing Al, Cr, Mn, Si, and V would be susceptible to oxidation in the presence of Ga{sub 2}O were validated by experimental results. In contrast to that reported previously, an alternate reaction mechanism for Ga uptake, which does not require concurrent alloy oxidation, controls Ga uptake for certain materials. A correlation between Ga solubility and uptake was noted.

  15. Mechanisms of oxide layer formation and destruction on a chromia former nickel base alloy in HTR environment; Mecanismes de formation et de destruction de la couche d'oxyde sur un alliage chrominoformeur en milieu HTR

    Rouillard, F


    Haynes 230 alloy which contains 22 wt.% chromium could be a promising candidate material for structures and heat exchangers (maximum operating temperature: 850-950 C) in Very High Temperature Reactors (VHTR). The feasibility demonstration involves to valid its corrosion resistance in the reactor specific environment namely impure helium. The alloys surface reactivity was investigated at temperatures between 850 and 1000 C. We especially focused on the influence of different parameters such as concentrations of impurities in the gas phase (carbon monoxide and methane, water vapour/hydrogen ratio), alloy composition (activities of Cr and C, alloying element contents) and temperature. Two main behaviours have been revealed: the formation of a Cr/Mn rich oxide layer at 900 C and its following reduction at higher temperatures. At 900 C, the water vapour is the main oxidizing gas. However in the initial times, the carbon monoxide reacts at the metal/oxide interface which involves a gaseous transport through the scale; CO mainly oxidizes the minor alloying elements aluminium and silicon. Above a critical temperature TA, the carbon in solution in the alloy reduces chromia. To ascribe the scale destruction, a model is proposed based on thermodynamic interfacial data for the alloy, oxide layer morphology and carbon monoxide partial pressure in helium; the model is then validated regarding experimental results and observations. (author)




    Full Text Available This paper presents the results of experimental work in dry turning of nickel based alloys (Haynes – 276 using Deferent tool geometer of cemented carbide tools. The turning tests were conducted at three different cutting speeds (112, 152, 201and 269 m/min while feed rate and depth of cut were kept constant at 0.2 mm/rev and 1.5 mm, respectively. The tool holders used were SCLCR with insert CCMT-12 and CCLNR – M12-4 with insert CNGN-12. The influence of cutting speed, tool inserts type and workpiece material was investigated on the machined surface roughness. The worn parts of the cutting tools were also examined under scanning electron microscope (SEM. The results showed that cutting speed significantly affected the machined surface finish values in related with the tool insert geometry. Insert type CCMT-12 showed better surface finish for cutting speed to 201 m/min, while insert type CNGN-12 surface roughness increased dramatically with increasing of speed to a limit completely damage of insert geometer beyond 152 m/min.

  17. MATE (Materials for Advanced Turbine Engines) Program, Project 3. Volume 2: Design, fabrication and evaluation of an oxide dispersion strengthened sheet alloy combustor liner

    Bose, S.; Sheffler, K. D.


    The suitability of wrought oxide dispersion strengthened (ODS) superalloy sheet for gas turbine engine combustor applications was evaluated. Two yttria (Y2O3) dispersion strengthened alloys were evaluated; Incoloy MA956 and Haynes Development Alloy (HDA) 8077 (NiCrAl base). Preliminary tests showed both alloys to be potentially viable combustor materials, with neither alloy exhibiting a significant advantage over the other. MA956 was selected as the final alloy based on manufacturing reproducibility for evaluation as a burner liner. A hybrid PW2037 inner burner liner containing MA956 and Hastelloy X components and using a louvered configuration was designed and constructed. The louvered configuration was chosen because of field experience and compatibility with the bill of material PW2037 design. The simulated flight cycle for the ground based engine tests consisted of 4.5 min idle, 1.5 min takeoff and intermediate conditions in a PW2037 engine with average uncorrected combustor exit temperature of 1527 C. Post test evaluation consisting of visual observations and fluorescent penetrant inspections was conducted after 500 cycles of testing. No loss of integrity in the burner liner was shown.

  18. Development of Grain Boundary Precipitate-Free Zones in a Ni-Mo-Cr-W Alloy

    Song, Jie; Field, Robert; Konitzer, Doug; Kaufman, Michael


    In this study, the morphology and development of precipitate-free zones (PFZs) near grain boundaries (GBs) in low coefficient of thermal expansion (CTE) Ni-Mo-Cr-W alloys (based on Haynes 244) have been investigated as a function of thermal history and composition using electron microscopy techniques. It is shown that the formation of wide, continuous PFZs adjacent to GBs can be largely attributed to a vacancy depletion mechanism. It is proposed that variations in the vacancy distributions that develop after solution heat treatment (SHT) and subsequent quenching and aging greatly influence the development of the γ'-Ni2(Mo,Cr) precipitates during the aging process and result in the development of PFZs of varying sizes. The relatively large (5 to 10 μm) PFZs are distinct from the smaller, more common PFZs that result from solute depletion due to GB precipitation that are typically observed after prolonged aging. During the course of this investigation, heat treatment parameters, such as aging time, SHT temperature, cooling rate after SHT, and heating rate to the aging temperature—all of which change vacancy concentration and distribution adjacent to GBs—were investigated and observed to have significant influence on both the size and morphology of the observed PFZs. In contrast to results from other Ni-based alloys studied previously, PFZ development in the current alloys was observed across a broad range of aging temperatures. This appears to be due to the high misfit strain energy of the γ' precipitates, resulting in a nucleation process that is sensitive to vacancy concentration. It is also shown that a slightly modified alloy with higher Mo concentrations develops smaller, more typical PFZs; this is presumably due to an increased driving force for γ' precipitation which overshadows the influence of misfit strain energy, thereby decreasing the sensitivity of precipitation on vacancy concentration.

  19. Aging and Phase Stability Studies of Alloy 22 FY08 Final Report

    Torres, S G


    This report is a compilation of work done over the past ten years in support of phase stability studies of Alloy 22 for the Yucca Mountain Project and contains information previously published, reported, and referenced. Most sections are paraphrased here for the convenience of readers. Evaluation of the fabrication processes involved in the manufacture of waste containers is important as these processes can have an effect on the metallurgical structure of an alloy. Because material properties such as strength, toughness, aging kinetics and corrosion resistance are all dependent on the microstructure, it is important that prototypes be built and evaluated for processing effects on the performance of the material. Of particular importance are welds, which have an as-cast microstructure with chemical segregation and precipitation of complex phases resulting from the welding process. The work summarized in this report contains information on the effects of fabrication processes such as solution annealing, stress mitigation, heat-to-heat variability, and welding on the kinetics of precipitation, mechanical, and corrosion properties. For a waste package lifetime of thousands of years, it is impossible to test directly in the laboratory the behavior of Alloy 22 under expected repository conditions. The changes that may occur in these materials must be accelerated. For phase stability studies, this is achieved by accelerating the phase transformations by increasing test temperatures above those anticipated in the proposed repository. For these reasons, Alloy 22 characterization specimens were aged at Lawrence Livermore National Laboratory (LLNL) Aging Facilities for times from 1 hour up to 8 years at temperatures ranging from 200-750 C. These data as well as the data from specimens aged at 260 C, 343 C, and 427 C for 100,028 hours at Haynes International will be used for performance confirmation and model validation.

  20. Translating VDM to Alloy

    Lausdahl, Kenneth


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

  1. Assessment of Embrittlement of VHTR Structural Alloys in Impure Helium Environments

    Crone, Wendy; Cao, Guoping; Sridhara, Kumar


    The helium coolant in high-temperature reactors inevitably contains low levels of impurities during steady-state operation, primarily consisting of small amounts of H{sub 2}, H{sub 2}O, CH{sub 4}, CO, CO{sub 2}, and N{sub 2} from a variety of sources in the reactor circuit. These impurities are problematic because they can cause significant long-term corrosion in the structural alloys used in the heat exchangers at elevated temperatures. Currently, the primary candidate materials for intermediate heat exchangers are Alloy 617, Haynes 230, Alloy 800H, and Hastelloy X. This project will evaluate the role of impurities in helium coolant on the stress-assisted grain boundary oxidation and creep crack growth in candidate alloys at elevated temperatures. The project team will: • Evaluate stress-assisted grain boundary oxidation and creep crack initiation and crack growth in the temperature range of 500-850°C in a prototypical helium environment. • Evaluate the effects of oxygen partial pressure on stress-assisted grain boundary oxidation and creep crack growth in impure helium at 500°C, 700°C, and 850°C respectively. • Characterize the microstructure of candidate alloys after long-term exposure to an impure helium environment in order to understand the correlation between stress-assisted grain boundary oxidation, creep crack growth, material composition, and impurities in the helium coolant. • Evaluate grain boundary engineering as a method to mitigate stress-assisted grain boundary oxidation and creep crack growth of candidate alloys in impure helium. The maximum primary helium coolant temperature in the high-temperature reactor is expected to be 850-1,000°C.Corrosion may involve oxidation, carburization, or decarburization mechanisms depending on the temperature, oxygen partial pressure, carbon activity, and alloy composition. These corrosion reactions can substantially affect long-term mechanical properties such as crack- growth rate and fracture

  2. Alloy Fabrication Laboratory

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

  3. Turbine Blade Alloy

    MacKay, Rebecca


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

  4. Processing of Advanced Cast Alloys for A-USC Steam Turbine Applications

    Jablonski, Paul D.; Hawk, Jeffery A.; Cowen, Christopher J.; Maziasz, Philip J.


    The high-temperature components within conventional supercritical coal-fired power plants are manufactured from ferritic/martensitic steels. To reduce greenhouse-gas emissions, the efficiency of pulverized coal steam power plants must be increased to as high a temperature and pressure as feasible. The proposed steam temperature in the DOE/NETL Advanced Ultra Supercritical power plant is high enough (760°C) that ferritic/martensitic steels will not work for the majority of high-temperature components in the turbine or for pipes and tubes in the boiler due to temperature limitations of this class of materials. Thus, Ni-based superalloys are being considered for many of these components. Off-the-shelf forged nickel alloys have shown good promise at these temperatures, but further improvements can be made through experimentation within the nominal chemistry range as well as through thermomechanical processing and subsequent heat treatment. However, cast nickel-based superalloys, which possess high strength, creep resistance, and weldability, are typically not available, particularly those with good ductility and toughness that are weldable in thick sections. To address those issues related to thick casting for turbine casings, for example, cast analogs of selected wrought nickel-based superalloys such as alloy 263, Haynes 282, and Nimonic 105 have been produced. Alloy design criteria, melt processing experiences, and heat treatment are discussed with respect to the as-processed and heat-treated microstructures and selected mechanical properties. The discussion concludes with the prospects for full-scale development of a thick section casting for a steam turbine valve chest or rotor casing.

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

    Gammaitoni, Loïc; Kelsen, Pierre


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


    Schonfeld, F.W.


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

  7. High strength alloys

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


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

  8. High strength alloys

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


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

  9. The Enlightenment of Hayne Law on Psychological Crisis Administration Concerning College Students%“海恩法则”对大学生心理危机管理的启示



    近年来,存在心理危机的大学生群体越来越大,给社会、家庭和学校造成一定压力,大学生心理健康问题正在被越来越多的人关注.“海恩法则”指出,任何不安全事故都是可以预防的,这对大学生心理危机管理以诸多启示:高度重视和建立大学生心理危机管理工作制度;建立大学生心理危机管理组织机构和心理危机干预队伍;完善高校大学生心理危机管理预案制度;构建大学生心理危机预警机制;心理危机干预走专业化道路;加强心理危机恢复管理.%In recent years, there is a psychological crisis, more and more college students to community, families and schools that caused some of the pressure. Their mental health problems are being attention by more and more people. The Hayne Law indicates that any insecurity accident can be prevented. This psychological crisis for a lot of inspiration which brings the following enlightenment of the law on psychological crisis administration concerning college students: take highly attention and establish psychological crisis administration system of college students;establish the troops of psychological crisis administration institution and intervening in psychological crisis; perfect pre - arranged planning system of psychological crisis administration for college students; construct early warning system of psychological crisis administration of college students; take the professional road of psychological crisis intervention; strengthen the restoring administration of psychological crisis.

  10. Biocompatibility of dental alloys

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


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

  11. Creep Resistant Zinc Alloy

    Frank E. Goodwin


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

  12. Creep Resistant Zinc Alloy

    Frank E. Goodwin


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

  13. Catalyst Alloys Processing

    Tan, Xincai


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


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


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


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


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

  16. Avaliação da atividade antioxidante e inibição da tirosinase do extrato das folhas do jatobá (Hymenaea stigonocarpa Mart. ex Hayne

    A.R. Miranda


    Full Text Available Espécies de Jatobá (Hymenaea stigonocarpa Mart. ex Hayne são tradicionalmente utilizadas para o tratamento de diversas doenças. Estudos quimiotaxonômicos têm relacionado o gênero Hymenaea como fonte potencial de compostos fenólicos, taninos, flavonoides, os quais apresentam atividade antioxidante, sendo assim substâncias potencialmente inibidoras da tirosinase, enzima responsável por defeitos da pigmentação da pele. Existem cerca de 15 espécies no gênero Hymenaea, das quais 13 ocorrem no Brasil. Assim, este trabalho foi realizado para avaliar os fenóis, a atividade antioxidante, a capacidade de quelação dos íons cobre, e a capacidade de inibição da tirosinase do extrato das folhas da espécie H. Stigonocarpa. O material botânico (folhas, foi colhido nas árvores da área de cerrado de preservação ambiental do campus universitário FESURV - Universidade de Rio Verde - GO, seco em estufa de circulação forçada a 42°C por 2 dias, seguindo para a obtenção dos extratos hexânico e etanólico. A determinação do conteúdo fenólico realizada através do reativo Folin Ciocalteau demonstrou ser o extrato bruto etanólico (EBE o que apresentou a maior concentração dessa classe (235,7 mg equivalente de ácido gálico por grama de EBE. Na avaliação da atividade captadora de radical, empregando o radical livre DPPH, novamente o extrato etanólico demonstrou atividade antioxidante mais elevada (IC50 = 19 ± 0,1 ppm. Para o procedimento de quelação de íons cobre, o extrato bruto etanólico não demonstrou tal capacidade. Quanto a inibição da enzima tirosinase, o extrato bruto etanólico, após 30 e 60 minutos, apresentou inibição de 38 e 48%, respectivamente.

  17. Investigation of Surface Treatments to Improve the Friction and Wear of Titanium Alloys for Diesel Engine Components

    Blau, Peter J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cooley, Kevin M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kirkham, Melanie J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bansal, Dinesh G. [Oak Ridge Associated Universities, TN (United States)


    This final report summarizes experimental and analytical work performed under an agreement between the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Office of Transportation Technologies, and UT-Battelle LLC. The project was directed by Jerry Gibbs, of the U.S. Department of Energy’s Propulsion Materials Program, with management by D. P. Stinton and J. A. Haynes of ORNL. Participants included Peter J. Blau (Principal Investigator), Kevin M. Cooley (senior technician), Melanie J. Kirkham (materials scientist) of the Materials Science and Technology Division or ORNL, and Dinesh G. Bansal, a post doctoral fellow employed by Oak Ridge Associated Universities (ORAU) and who, at the time of this writing, is an engineer with Cummins, Inc. This report covers a three-year effort that involved two stages. In the first stage, and after a review of the literature and discussions with surface treatment experts, a series of candidate alloys and surface treatments for titanium alloy (Ti-6Al-4V) was selected for initial screening. After pre-screening using an ASTM standard test method, the more promising surface treatments were tested in Phase 2 using a variable loading apparatus that was designed and built to simulate the changing load patterns in a typical connecting rod bearing. Information on load profiles from the literature was supplemented with the help of T.C. Chen and Howard Savage of Cummins, Inc. Considering the dynamic and evolving nature of materials technology, this report presents a snapshot of commercial and experimental bearing surface technologies for titanium alloys that were available during the period of this work. Undoubtedly, further improvements in surface engineering methods for titanium will evolve.

  18. Ductile transplutonium metal alloys

    Conner, William V.


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

  19. Ultrahigh temperature intermetallic alloys

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


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

  20. Mg based alloys obtained by mechanical alloying

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


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


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


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

  2. Analysis of niobium alloys.

    Ferraro, T A


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


    Schell, D.H.; Sheinberg, H.


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

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

    American Society for Testing and Materials. Philadelphia


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

  5. Alloy Selection System



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

  6. Strength of Hard Alloys,

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

  7. First Everlasting Alloy



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

  8. Machining of titanium alloys


    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.

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

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


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

  10. Impact toughness of laser alloyed aluminium AA1200 alloys

    Mabhali, Luyolo AB


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


    Berat Barıs BULDUM


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

  12. Selective dissolution in binary alloys

    McCall, Carol Rene

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

  13. Structural thermodynamics of alloys

    Manenc, Jack


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

  14. De-alloyed platinum nanoparticles

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


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

  15. Shape Memory Alloys

    Deexith Reddy


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

  16. Neutron absorbing alloy

    Hayashi, Masayuki


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

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

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


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

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

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


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

  19. Pemilihan Bahan Alloy Untuk Konstruksi Gigitiruan

    Medila Dahlan


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

  20. Strip Casting of High Performance Structural Alloys

    S S Park; J G Lee; Nack J Kim


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

  1. Tungsten Alloy Outgassing Measurements

    Rutherfoord, John P; Shaver, L


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

  2. Pareto-optimal alloys

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


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

  3. Alloy catalyst material


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

  4. Shape Memory Alloy Actuator

    Baumbick, Robert J. (Inventor)


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

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


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

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

    Zongxia LIU


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

  7. Advanced ordered intermetallic alloy deployment

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


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

  8. Tungsten carbide laser alloying of a low alloyed steel

    Cojocaru, Mihai; Taca, Mihaela


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

  9. Filler metal alloy for welding cast nickel aluminide alloys

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


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

  10. Filler metal alloy for welding cast nickel aluminide alloys

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


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

  11. Materials data handbook, Inconel alloy 718

    Sessler, J.; Weiss, V.


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

  12. SINTERED REFRACTORY TUNGSTEN ALLOYS. Gesinterte hochschmelzende wolframlegierungen

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


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

  13. High-temperature Titanium Alloys

    A.K. Gogia


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

  14. Porosity of porous Al alloys


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

  15. Multicomponent and High Entropy Alloys

    Brian Cantor


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

  16. Duct and cladding alloy

    Korenko, Michael K.


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

  17. Shape memory alloy actuator

    Varma, Venugopal K.


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

  18. Analysis of laser alloyed surfaces

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


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

  19. Aluminum alloy impact sparkling

    M. Dudyk


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

  20. Oligocrystalline shape memory alloys

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


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



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

  2. Radiation Effects in Refractory Alloys

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


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

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

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


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

  4. Shape memory alloy thaw sensors

    Shahinpoor, Mohsen; Martinez, David R.


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

  5. Electron Theory in Alloy Design

    Pettifor, DG


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

  6. Mo-Si alloy development

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


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

  7. Heat storage in alloy transformations

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


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

  8. Wedlable nickel aluminide alloy

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


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

  9. Galvanic cells including cobalt-chromium alloys.

    Gjerdet, N R


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

  10. About Alloying of Aluminum Alloys with Transition Metals

    Zakharov, V. V.


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

  11. [Prosthetic dental alloys. 1].

    Quintero Engelmbright, M A


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

  12. [Prosthetic dental alloys (2)].

    Quintero Englembright, M A


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

  13. Density of Liquid Ni-Cr Alloy


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

  14. Mechanically Alloyed High Entropy Composite

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


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

  15. Modeling dissolution in aluminum alloys

    Durbin, Tracie Lee


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

  16. Rapidly solidified aluminum alloy powder

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


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

  17. Alloying and Casting Furnace for Shape Memory Alloys Project

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

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

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


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

  19. Laser surface alloying of aluminium-transition metal alloys

    Almeida, A.


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

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

  20. Metallic alloy stability studies

    Firth, G. C.


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

  1. Lead telluride alloy thermoelectrics

    Aaron D. LaLonde


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

  2. Emissivity measurements on aeronautical alloys

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


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

  3. Ni{sub 3}Al aluminide alloys

    Liu, C.T.


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

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

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


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

  5. Kinetics of aluminum lithium alloys

    Pletcher, Ben A.


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

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

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


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

  7. Alloys developed for high temperature applications

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


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

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


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

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

    徐子文; 黄正; 阮中健


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

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

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


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

  11. Shape memory alloy flexures

    Bellouard, Yves; Clavel, Reymond


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

  12. Zinc alloy enhances strength and creep resistance

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


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

  13. Thermomechanical behavior of comercial yellow gold alloy

    Miloš G. Djordjević


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

  14. Oxidation of low cobalt alloys

    Barrett, C. A.


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

  15. Improved thermal treatment of aluminum alloy 7075

    Cocks, F. H.


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

  16. Impact toughness of laser surface alloyed Aluminium

    Mabhali, Luyolo AB


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

  17. Corrosion Behaviour of New Zr Alloys

    Tolksdorf, E.


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

  18. Current research situation of titanium alloys in China


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


    Shor, R.S.; Vogler, S.


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

  20. High strength, tough alloy steel

    Thomas, Gareth; Rao, Bangaru V. N.


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

  1. Alloy 718 for Oilfield Applications

    deBarbadillo, John J.; Mannan, Sarwan K.


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

  2. Bulk nano-crystalline alloys

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


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


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


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

  4. Alloy softening in binary iron solid solutions

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


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

  5. Surface Tension Calculation of Undercooled Alloys


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

  6. An introduction to surface alloying of metals

    Hosmani, Santosh S; Goyal, Rajendra Kumar


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

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

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


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

  8. Applications of shape memory alloys in Japan

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


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

  9. High Damping Alloys and Their Application

    Fuxing Yin


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

  10. Passive Corrosion Behavior of Alloy 22

    Rebak, R B; Payer, J H


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

  11. Paracrystalline property of high-entropy alloys

    Shaoqing Wang


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

  12. Passive Corrosion Behavior of Alloy 22

    R.B. Rebak; J.H. Payer


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

  13. Nickel, cobalt, and their alloys


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

  14. Hydrostatic extrusion of magnesium alloys

    Sillekens, W.H.; Bohlen, J.


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

  15. Gold color in dental alloys.

    Cameron, T


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

  16. Ultrasonic processing of aluminum alloys

    Zhang, L.


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

  17. Superb nanocrystalline alloys for plating


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

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

    林建国; 魏浩岩; 黄正


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

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

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


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


    A. G. Slutsky


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

  1. Hydrogen ingress into copper-nickel alloys

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


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

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

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


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

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

    Jiang, Jian-Jun; Gasik, Michael

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

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

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


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

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

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


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

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

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


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

  7. New Dental Alloys with Special Consumer Properties



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

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

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


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

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

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


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

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


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

  11. Theory of Random Anisotropic Magnetic Alloys

    Lindgård, Per-Anker


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

  12. Magnetic Characteristics of Two Metglas Alloys

    Blatnik, Marie; SNS nEDM Collaboration


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

  13. Bulk amorphous Mg-based alloys

    Pryds, Nini


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

  14. Bonding theory for metals and alloys

    Wang, Frederick E


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

  15. A lightweight shape-memory magnesium alloy.

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


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

  16. Wetting behavior of alternative solder alloys

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


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

  17. Recrystallization of Al-Sc alloys

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

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

  18. Biocorrosion study of titanium-nickel alloys.

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


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

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


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

  20. Spark alloying of VK8 and T15K6 hard alloys

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


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

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


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

  2. High toughness-high strength iron alloy

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


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

  3. The Fatigue of Powder Metallurgy Alloys.


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

  4. Aspects of precipitation in alloy Inconel 718

    Azadian, Saied


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

  5. Advanced powder metallurgy aluminum alloys and composites

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


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

  6. The oxidation and corrosion of ODS alloys

    Lowell, Carl E.; Barrett, Charles A.


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

  7. Oxidation And Hot Corrosion Of ODS Alloy

    Lowell, Carl E.; Barrett, Charles A.


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

  8. Alloy nanoparticle synthesis using ionizing radiation

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


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

  9. Cobalt-Base Alloy Gun Barrel Study


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

  10. Deformation Driven Alloying and Transformation


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

  11. Titanium alloys Russian aircraft and aerospace applications

    Moiseyev, Valentin N


    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.

  12. New aluminium alloys with high lithium content

    Schemme, K.; Velten, B.


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

  13. Casting Characteristics of Aluminum Die Casting Alloys

    Makhlouf M. Makhlouf; Diran Apelian


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

  14. Ultralow-fatigue shape memory alloy films

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


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

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


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

  16. Nanodispersed boriding of titanium alloy

    Kateryna O. Kostyk


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

  17. Pack cementation coatings for alloys

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


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

  18. Microbial corrosion of aluminum alloy.

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


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

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

    Bi-Cheng Zhou


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

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

    Kwak Z.


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

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

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


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

  2. Mechanical Properties of Nb25Mo25Ta25W25 and V20Nb20Mo20Ta20W20 Refractory High-Entropy Alloys (Preprint)


    yield stress (YS) of the studied HEAs and two high-temperature Ni-based superalloys, Inconel 718 [9] and Haynes 230 [10 Figure 3 ]. Inconel 718 is a...YS of Inconel 718 rapidly decreases to 138 MPa with a further increase in temperature to 982°C, while melting occurs at ~1210°C. Inconel 718 is...that of Haynes 230 at all studied temperatures and higher than that of Inconel 718 at temperatures above 800°C (see Figure 3). Moreover, the

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

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


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

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

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


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


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


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

  6. Zirconium alloys produced by recycling zircaloy tunings

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


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

  7. Measurement of oxide adherence to PFM alloys.

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


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

  8. Progress in High-Entropy Alloys

    Gao, Michael C


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




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

  10. Castable nickel aluminide alloys for structural applications

    Liu, Chain T.


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

  11. Design optimization of shape memory alloy structures

    Langelaar, M.


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

  12. Design optimization of shape memory alloy structures

    Langelaar, M.


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

  13. Ti-Pt Alloys form mechanical milling

    Nxumalo, S


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

  14. Friction Stir Welding of Aluminum Alloys

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


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

  15. Laser alloyed Al-Ni-Fe coatings

    Pityana, SL


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

  16. Trends of Chinese RE Hydrogen Storage Alloys


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

  17. Alloys of clathrate allotropes for rechargeable batteries

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


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

  18. Electroplating Zn-Al Alloy Technology


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

  19. Thermally activated martensite formation in ferrous alloys

    Villa, Matteo; Somers, Marcel A. J.


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

  20. Corrosion resistance improvement of titanium base alloys

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


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

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

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


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

  2. Corrosion resistance improvement of titanium base alloys

    Mihai V. Popa


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

  3. Mechanical behaviour of aluminium-lithium alloys

    N Eswara Prasad; A A Gokhale; P Rama Rao


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

  4. Internal chlorination of Ni-Cr alloys

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


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

  5. Rapidly solidified ferromagnetic shape memory alloys

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


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

  6. Long - range foundry Al composite alloys

    A. D. Mekhtiev


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

  7. Concepts in surface alloying of metals

    Santosh S. Hosmani


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

  8. Superior hydrogen storage in high entropy alloys

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


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

  9. Superconductivity in Metals and Alloys


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


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


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

  11. Phase transformations during sintering of mechanically alloyed TiPt

    Nxumalo, S


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

  12. Process Simulation and Modeling for Advanced Intermetallic Alloys.


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

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

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


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

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

    Mao, Jie

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

  15. NiAl alloys for structural uses

    Koss, D. A.


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

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

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


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

  17. Environmentally Assisted Cracking of Nickel Alloys - A Review

    Rebak, R


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

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

    Feng XIAO; Liang FANG


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

  19. Indium Helps Strengthen Al/Cu/Li Alloy

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


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

  20. Thermal aging effects in refractory metal alloys

    Stephens, Joseph R.


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

  1. Aeronautical requirements for Inconel 718 alloy

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


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

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

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


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

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

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


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

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

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


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

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


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

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

    W.K. Krajewski


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

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

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


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

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

    王家淳; 于荣海; 刘庆


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

  9. Fatigue Characteristics of Selected Light Metal Alloys

    Cieśla M.


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

  10. Electroplated solder alloys for flip chip interconnections

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


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

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

    J. Kozana


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

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

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


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

  13. Combustion synthesis of bulk nanocrystalline iron alloys

    Licai Fu; Jun Yang; Weimin Liu


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

  14. Graded coatings for metallic implant alloys

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


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

  15. Stress corrosion cracking of titanium alloys

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


    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.

  16. Thermodynamics and Structure of Plutonium Alloys

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


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

  17. Current assisted superplastic forming of titanium alloy

    Wang Guofeng


    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.

  18. Electrochemical behaviour of passive zirconium alloys

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


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

  19. Corrosion behavior of magnesium and magnesium alloys

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


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

  20. Electrochemical Impedance Spectroscopy Of Metal Alloys

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


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

  1. New alloys to conserve critical elements

    Stephens, J. R.


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

  2. Medical applications of shape memory alloys

    Machado L.G.


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

  3. Magnetization curve modelling of soft magnetic alloys

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


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

  4. Superelastic effect in polycrystalline ferrous alloys.

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


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

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

    А.М. Хімко


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

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

    American Society for Testing and Materials. Philadelphia


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

  7. Silver-hafnium braze alloy

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


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

  8. Shape memory alloy based motor

    S V Sharma; M M Nayak; N S Dinesh


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

  9. Rapid solidification of immiscible alloys

    Bosco, Enrica; Rizzi, Paola; Baricco, Marcello E-mail:


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

  10. NASA-427: A New Aluminum Alloy

    Nabors, Sammy A.


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

  11. Combustion synthesis of bulk nanocrystalline iron alloys

    Licai Fu


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

  12. Solidification of Al alloys under electromagnetic field



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

  13. Theory of Rare-Earth Alloys

    Lindgård, Per-Anker


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

  14. Stress-corrosion cracking of titanium alloys.

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


    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.

  15. On Silicides in High Temperature Titanium Alloys

    C. Ramachandra


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

  16. Optical Transmittance of Anodically Oxidized Aluminum Alloy

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


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

  17. Ternary alloy nanocatalysts for hydrogen evolution reaction



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

  18. Combustion synthesis of bulk nanocrystalline iron alloys

    Licai Fu; Jun Yang; Weimin Liu


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

  19. Shape Memory Alloy Rock Splitters (SMARS)

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


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

  20. Thermal barrier coating for alloy systems

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


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

  1. High-entropy alloy: challenges and prospects

    Y.F. Ye


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

  2. Room temperature creep in metals and alloys

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


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

  3. Modeling wear of cast Ti alloys.

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


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

  4. Simulation of nuclei morphologies for binary alloy


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

  5. Printability of alloys for additive manufacturing.

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


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

  6. Solid solution lithium alloy cermet anodes

    Richardson, Thomas J.


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

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

    Rizk Mostafa Shalaby


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

  8. Corrosion performance of structural alloys.

    Natesan, K.


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

  9. Lightweight Protective Coatings For Titanium Alloys

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


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

  10. Internal gettering by metal alloy clusters

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


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

  11. Titanium and titanium alloys fundamentals and applications

    Peters, Manfred


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

  12. Microstructure and Service Properties of Copper Alloys

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


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

  13. Mechanocaloric effects in Shape Memory Alloys

    Manosa, Lluis; Planes, Antoni


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

  14. Self-Organized Growth of Alloy Superlattices

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


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

  15. Electrical Conductivity of Aluminium Alloy Foams

    凤仪; 郑海务; 朱震刚; 祖方遒


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

  16. Phonon broadening in high entropy alloys

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


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

  17. Pulse reversal plating of nickel alloys

    Tang, Peter Torben


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

  18. Novel Directional Solidification Processing of Hypermonotectic Alloys

    Kaukler, William; Fedoseyev, Alex


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

  19. Alloys For Corrosive, Hydrogen-Rich Environments

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


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

  20. Solid metal induced embrittlement of titanium alloys

    Åkerfeldt, Pia


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

  1. Degassing of Aluminum Alloys Using Ultrasonic Vibration

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


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

  2. Initial cytotoxicity of novel titanium alloys.

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


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

  3. Capacity retention in hydrogen storage alloys

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


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

  4. Surface energy of metal alloy nanoparticles

    Takrori, Fahed M.; Ayyad, Ahmed


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

  5. Point-charge electrostatics in disordered alloys

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


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

  6. Biocorrosion study of titanium-cobalt alloys.

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


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

  7. Hydrogen storage systems from waste Mg alloys

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


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

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

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


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

  9. An Analysis of Selected Properties of ZA Alloys

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


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

  10. Study of fatigue behaviour of 7475 aluminium alloy

    B B Verma; J D Atkinson; M Kumar


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

  11. Nondestructive Evaluation of Ni-Ti Shape Memory Alloy

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


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

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

    Chen Dongfeng


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

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

    Akihiro Makino


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

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

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


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

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

    Erenc-Sędziak T.


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

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

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


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

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

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


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



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

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

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


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

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

    Elahi, Mohammad Reza, E-mail: [School of Metallurgy and Materials, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Sohi, Mahmoud Heydarzadeh; Safaei, Abdolghayoom [School of Metallurgy and Materials, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)


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

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

    Baorong Hou; Yantao Li; Yanxu Li; Jinglei Zhang


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

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


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

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


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

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


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

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

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


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

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

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


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

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

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


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

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


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


    Roberto. A. Rodríguez-Díaz


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

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

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


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

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

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


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

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

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


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

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

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


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

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

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


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

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

    Jensen, William B.


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

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

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


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

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

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


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

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

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


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

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


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

  20. A rapid stress-corrosion test for aluminum alloys

    Helfrich, W. J.


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

  1. Wear resistant steels and casting alloys containing niobium carbide

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


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

  2. Production, Properties and Applications of Bulk Amorphous Alloys

    Tao Zhang; Akihisa Inoue


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

  3. Assessment of Al-Li Alloys for Cryotanks

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


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

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



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

  5. Advances of Titanium Alloys and Its Biological Surface Modification

    XU Ke-wei; HUANG Ping


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

  6. Composite purification technology and mechanism of recycled aluminum alloys

    房文斌; 耿耀宏; 安阁英; 叶荣茂


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

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

    Alhazaa, Abdulaziz Nasser

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

  8. Surface Features of Nanocrystalline Alloys

    Marcel Miglierini


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

  9. [Study on biocompatibility of titanium alloys].

    Kodama, T


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


    A. V. Alifanov


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


    Kudret KANDEMİR


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

  12. Alloy element redistribution during sintering of powder metallurgy steels

    Tahir, Abdul Malik


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

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

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


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

  14. Microstructure and Aging of Powder-Metallurgy Al Alloys

    Blackburn, L. B.


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

  15. Evolution of Hydrogen Storage Alloys Prepared by Special Methods

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


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

  16. Technique of Aluminum Alloy Composite by Inversion Casting


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

  17. Shape-Memory-Alloy Actuator For Flight Controls

    Barret, Chris


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

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

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


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

  19. Experience with ferrosilicoaluminum alloy during deoxidation of steel

    A. Mekhtiyev


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

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

    Kishan Roodbari, Marzieh


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

  1. Microstructures and properties of aluminum die casting alloys

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


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

  2. Welding of Aluminum Alloys to Steels: An Overview


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

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

    American Society for Testing and Materials. Philadelphia


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

  4. Fermi surface effects in terbium alloys

    Burgardt, P.


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

  5. Explosive compaction of CuCr alloys

    李金平; 罗守靖; 龚朝晖; 牛玮; 纪松


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

  6. Complex precipitation pathways in multicomponent alloys

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


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

  7. A jumping shape memory alloy under heat.

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


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

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

    Gilman, P. S.


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

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

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


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


    О. V. Diachenko


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

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

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


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

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

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


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

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

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


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

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

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


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

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

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


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

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

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


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

  17. 21 CFR 872.3710 - Base metal alloy.


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

  18. 21 CFR 872.3080 - Mercury and alloy dispenser.


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

  19. 21 CFR 872.3060 - Noble metal alloy.


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

  20. Investigation of joining techniques for advanced austenitic alloys

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


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

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

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


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

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

    A. Dudek


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

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

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


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

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

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


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

  5. New development of anodizing process of magnesium alloys

    BAI Li-qun; LI Di


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

  6. Progress of Palladium Alloy Membranes in Hydrogen Energy

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


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

  7. Microstructure and properties of modified and conventional 718 alloys

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


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



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

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

    Shield, J.E.; Goldman, A.I.; Anderson, I.E.; Ellis, T.W.; McCallum, R.W.; Sordelet, D.J.


    A method of making quasicrystalline alloy particulates is disclosed wherein an alloy is superheated and the melt is atomized to form generally spherical alloy particulates free of mechanical fracture and exhibiting a predominantly quasicrystalline in the atomized condition structure. The particulates can be plasma sprayed to form a coating or consolidated to form an article of manufacture. 3 figs.

  10. Influence of finishing on the electrochemical properties of dental alloys.

    Kaneko, T; Hattori, M; Hasegawa, K; Yoshinari, M; Kawada, E; Oda, Y


    Dental alloy surface finishing procedures of may influence their electrochemical behavior, which is used to evaluate their corrosion resistance. We examined the polarization resistance and potentiodynamic polarization profile of the precious-metal alloys, Type 4 gold alloy and silver-palladium alloy, and the base-metal alloys, nickel-chromium alloy, cobalt-chromium alloy, and CP-titanium. Three types of finishing procedure were examined: mirror-finishing using 0.05 micron alumina particles, polishing using #600 abrasive paper and sandblasting. Dissolution of the alloy elements in 0.9% NaCl solution was also measured and compared with the electrochemical evaluation. The corrosion resistance of the dental alloys was found to relate to finishing as follows: The polarization resistance and potentiodynamic polarization behavior revealed that the corrosion resistance improved in the order of sandblasting, #600-abrasive-paper polishing, and mirror-finishing. While the corrosion potential, critical current density and passive current density varied depending on the type of finishing, the transpassive potential remained unchanged. The influence of finishing on the corrosion resistance of precious-metal alloys was less significant than on that of base-metal alloys. A mirror-finishing specimen was recommended for use in evaluation of the corrosion resistance of various dental alloys.

  11. Film induced intergranular cracking of binary noble alloys

    Friedersdorf, F. [Bureau of Mines, Albany, OR (United States); Sieradzki, K. [Arizona State Univ., Tempe, AZ (United States)


    Dealloying of a binary noble alloy produces a porous layer rich in the more noble element. Application of a tensile load may initiate a brittle intergranular crack in the dealloyed layer that advances into the unattached material. The relationships between the dealloying potential, dealloyed layer thickness and alloy susceptibility to film induced intergranular cracking have been studied. Ag-Au alloys were studied.

  12. Nanostructured Platinum Alloys for Use as Catalyst Materials

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


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

  13. Magnesium alloy AZ63A reinforcement by alloying with gallium and using high-disperse ZrO2 particles

    J. Khokhlova


    Full Text Available The aim of this work was to obtain an experimental magnesium alloy by remelting standard AZ63A alloy with addition of gallium ligatures and ZrO2 particles. This allowed reinforcement of alloy and increase its hardness and Young's modulus. The chemical analysis of this alloy shows two types of structures which are evenly distributed in volume. Thus we can conclude that reinforcing effect is the result of formation of intermetallic phase Mg5-Ga2.

  14. Electrocatalysts having platium monolayers on palladium, palladium alloy, and gold alloy core-shell nanoparticles, and uses thereof

    Adzic, Radoslav (Setauket, NY); Mo, Yibo (Naperville, IL); Vukmirovic, Miomir (Port Jefferson Station, NY); Zhang, Junliang (Rochester, NY)


    The invention relates to platinum-coated particles useful as fuel cell electrocatalysts. The particles are composed of a noble metal or metal alloy core at least partially encapsulated by an atomically thin surface layer of platinum atoms. The invention particularly relates to such particles having a palladium, palladium alloy, gold alloy, or rhenium alloy core encapsulated by an atomic monolayer of platinum. In other embodiments, the invention relates to fuel cells containing these electrocatalysts and methods for generating electrical energy therefrom.

  15. Effects of alloy composition in alleviating embrittlement problems associated with the tantalum alloy T-111

    Stephens, J. R.


    The causes of aging embrittlement in T-111 (Ta-8W-2Hf) and the effect of alloy modification were investigated. Results show that T-111 possesses a critical combination of tungsten and hafnium that leads to loss in ductility at -196 C after aging near 1040 C. It was found that this occurs because tungsten enhances hafnium segregation to grain boundaries, which also leads to increased susceptibility to hydrogen embrittlement. Aging embrittlement was not observed in tantalum alloys with reduced tungsten or hafnium contents; most of the alloys studied have lower strengths than T-111 and exhibit susceptibility to hydrogen embrittlement.

  16. XAFS Study on Solid State Amorphization of Alloys by Mechanical Alloying


    Structural evolution of alloys by ball-milling during solid stateamorphization were studied by means of XAFS technique. The first one is amorphization process of Fe and B powder mixtures by mechanical alloying (MA), and the second one is amorphization process of ordered B2 CoZr intermetallic compound by mechanical milling (MM). The mixing process of Fe and B and disintegration process of ordered B2 CoZr intermetallic compound crystal were observed clearly in atomic level by XAFS method. The micro-mechanism of amorphization process of alloy by ball-milling was discussed.

  17. Non-alloyed Ni3Al based alloys – preparation and evaluation of mechanical properties

    J. Malcharcziková


    Full Text Available The paper reports on the fabrication and mechanical properties of Ni3Al based alloy, which represents the most frequently used basic composition of nickel based intermetallic alloys for high temperature applications. The structure of the alloy was controlled through directional solidification. The samples had a multi-phase microstructure. The directionally solidified specimens were subjected to tensile tests with concurrent measurement of acoustic emission (AE. The specimens exhibited considerable room temperature ductility before fracture. During tensile testing an intensive AE was observed.

  18. Separation of magnetic phases in alloys

    Takacs, J. [Department of Engineering Science, University of Oxford, 5. Pound Close, Yarnton, Oxon OX5 1QG, Oxford (United Kingdom)], E-mail:; Meszaros, I. [Department of Materials Science and Technology, Budapest University of Technology and Economics, Budapest (Hungary)


    In this paper we present a study of the separation of phases in multi-phase alloys. The proposed technique is based on the hyperbolic model of magnetization. By using this model it is possible to decompose the magnetic phases of alloys and determine their magnetic properties separately. Experimental verification was carried out on a transformer-like setup, constructed from layered samples representing the various magnetic phases. The samples were constructed from elements of strongly different magnetic properties. The results given by the model are in an excellent agreement with the experimental results, giving justification for the proposed method of decomposition. The proposed method is the first step towards the recognition and the separation of magnetic constituencies of different magnetic properties in an alloy by analytical means.

  19. High temperature alloys: their exploitable potential

    Marriott, J.B.; Merz, M.; Nihoul, J.; Ward, J. (eds.) (Commission of the European Communities, Petten (Netherlands). Joint Nuclear Research Center; NET-TEAM, Garching (DE))


    This book is the proceedings of a conference dealing with fundamental and technical aspects of the applications of high temperature alloys. It is split into five sections which cover the opening session of the conference and four further sessions covering: the theoretical and practical limits for HT alloys; the potential for development in alloys and processing; engineering considerations; the future outlook. The different sessions each included a number of invited papers followed by a series of posters and were concluded by a presentation of a 'synthesis' by a session rapporteur and general discussion. This structure is retained in the proceedings, including the discussion points in those cases where the authors have provided written answers to the questions raised. This book will be of interest to metallurgists, materials scientists, physicists and research workers in high temperature materials.

  20. The Mg impurity in nitride alloys

    Zvanut, M. E.; Willoughby, W. R.; Sunay, U. R. [Department of Physics, University of Alabama at Birmingham, Birmingham AL (United States); Koleske, D. D.; Allerman, A. A. [Sandia National Laboratory, Albuquerque NM (United States); Wang, Ke; Araki, Tsutomu [Department of Photonics, Ritsumeikan University, Kusatsu, Shiga (Japan); Nanishi, Yasushi [Department of Photonics, Ritsumeikan University, Kusatsu, Shiga, Japan and WCU Program, Department of Materials Science and Engineering, Seoul National University, Seoul (Korea, Republic of)


    Although several magnetic resonance studies address the Mg acceptor in GaN, there are few reports on Mg doping in the alloys, where hole production depends strongly on the Al or In content. Our electron paramagnetic resonance (EPR) measurements of the p-type alloys suggest that the Mg impurity retains the axial symmetry, characteristic of a p-type dopant in both alloys; however, In and Al produce additional, different characteristics of the acceptor. In InGaN, the behavior is consistent with a lowering of the acceptor level and increasing hole density as In concentration increases. For AlGaN, the amount of neutral Mg decreases with increasing Al content, which is attributed to different kinetics of hydrogen diffusion thought to occur in samples with higher Al mole fraction.

  1. Electrochemical formation of holmium-cobalt alloys


    The electrochemical formation processes of holmium-cobalt alloys on cobalt cathode in molten HoC13-KC1 wereinvestigated by cyclic voltammetry and open current potential-time curve after potentiostatic electrolysis. The structure ofHo-Co alloys' films deposited on cobalt electrode by potentiostatic electrolysis was characterized by X-ray diffraction. Thestandard Gibbs free energies of formation for the intermetallic compounds of Ho and Co were determined. The diffusioncoefficient and diffusion activation energy of Ho atom in the alloy phase were calculated to be 10-10-10-11 cm2/s and 96.0kJ/mol, respectively, from the current-time curve at potential step.

  2. Hydrogenation properties of Mg-Al alloys

    Andreasen, Anders


    In this paper the properties of Mg-Al alloys in relation to hydrogen storage are reviewed. The main topics of this paper are materials preparation, hydrogen capacity, thermodynamics of hydride formation, and the kinetics of hydride formation and decomposition. Hydrogenation of Mg-Al leads...... to disproportionation with the formation of magnesium hydride and metallic aluminum as the final product. Experimental evidence renders this process reversible. It is observed that the enthalpy of hydride formation of magnesium is lowered upon alloying with Al due to a slightly endothermic disproportionation reaction....... Further, it is found that the kinetics of hydrogenation, as well dehydrogenation, may be significantly improved by alloying compared to pure Mg. The expense of these improvements of the hydrogenation/dehydrogenation properties is a lower gravimetric hydrogen density in the hydrogenated product, (C) 2008...

  3. Microstructure and Slip Character in Titanium Alloys

    D. Banerjee


    Full Text Available Influence of microstructures in titanium alloys on the basic parameters of deformation behaviour such as slip character, slip length and slip intensity have been explored. Commercial titanium alloys contain the hexagonal close packed (alpha and body centred cubic (bita phases. Slip in these individual phases is shown to be dependent on the nature of alloying elements through their effect on phase stability as related to decomposition into ordered or w structures. When alpha and bita coexist, their relative crystallographic orientations, size, shape and volume fraction, control the nature of slip. For a given composition, structure may be manipulated through appropriate thermomechanical treatment to obtain the desired deformation behaviour and therefore fracture mode.

  4. Fatigue - corrosion of endoprosthesis titanium alloys.

    Cornet, A; Muster, D; Jaeger, J H


    Commercial total hip prostheses often show certain metallurgical faults (porosities, coarse grains, growth dendrites, carbide networks). In order to investigate more accurately the role played by these different parameters in prostheses failure we performed a large number of systematic corrosion, fatigue and fatigue - corrosion tests on these materials and on commercial total hip prostheses. Ultimate strengthes seem to be reached for cast cobalt alloys, whereas titanium alloys, such as Ta 6 V, present very high fatigue limit under corrosion. Thus, rotative bending fatigue - corrosion tests in biological environment provide values about 50 DaN/mm2. This value, is nevertheless appreciably higher than those obtained with stellites and stainless steel. Titanium alloys, because of their mechanical performances, their weak Young's modulus (11000 DaN/mm2) and their relative lightness (4.5. g/cm3), which are associated with a good biocompatibility, seem very promising for permanent implants realisation.

  5. Cast Aluminum Alloy for High Temperature Applications

    Lee, Jonathan A.


    Originally developed by NASA as high performance piston alloys to meet U.S. automotive legislation requiring low exhaust emission, the novel NASA alloys now offer dramatic increase in tensile strength for many other applications at elevated temperatures from 450 F (232 C) to about 750 F (400 C). It is an ideal low cost material for cast automotive components such as pistons, cylinder heads, cylinder liners, connecting rods, turbo chargers, impellers, actuators, brake calipers and rotors. It can be very economically produced from conventional permanent mold, sand casting or investment casting, with silicon content ranging from 6% to 18%. At high silicon levels, the alloy exhibits excellent dimensional stability, surface hardness and wear resistant properties.

  6. Aluminum-lithium alloy development for thixoforming

    Sauermann, R.; Friedrich, B. [IME Process Metallurgy and Metal Recycling, RWTH Aachen Univ. (Germany); Puettgen, W.; Bleck, W. [IEHK Inst. for Ferrous Metallurgy, RWTH Aachen Univ. (Germany); Balitchev, E.; Hallstedt, B.; Schneider, J.M. [MCh Materials Chemistry, RWTH Aachen Univ. (Germany); Bramann, H.; Buehrig-Polaczek, A. [GI Foundry Inst., RWTH Aachen Univ. (Germany); Uggowitzer, P.J. [ETH Zuerich, Metal Physics and Technology (Germany)


    This paper presents a scientific contribution to the development of lightweight/high-performance Al-Li alloys suitable for semi-solid processing. Thermodynamic calculations identified the most promising compositions with focus on the solidus-liquidus interval, fraction of solid-versus-temperature and phase reactions. The synthesis of Al-Li precursor billets was performed by overpressure induction melting in controlled atmosphere. DTA and microstructure investigations on Al-Li specimens were carried out as well as thixocasting trials of demonstrator components. New rheocasting of Al-Li alloys was investigated to identify the potential of this alternative precursor material route. It is shown that specifically developed Al-Li alloys offer great potential for semi-solid manufacturing. (orig.)

  7. High-strength iron aluminide alloys

    McKamey, C.G.; Maziasz, P.J.


    Past studies have shown that binary Fe{sub 3}Al possesses low creep-rupture strength compared to many other alloys, with creep-rupture lives of less than 5 h being reported for tests conducted at 593{degrees}C and 207 MPa. The combination of poor creep resistance and low room-temperature tensile ductility due to a susceptibility to environmentally-induced dynamic hydrogen embrittlement has limited use of these alloys for structural applications despite their excellent corrosion properties. With regard to the ductility problem, alloy development efforts have produced significant improvements, with ductilities of 10-20% and tensile yield strengths as high as 500 MPa being reported. Likewise, initial improvements in creep resistance have been realized through small additions of Mo, Nb, and Zr.

  8. Microstructure and Service Properties of Copper Alloys

    Polok-Rubiniec M.


    Full Text Available This elaboration shows the effect of combined heat treatment and cold working on the structure and utility properties of alloyed copper. As the test material, alloyed copper CuTi4 was employed. The samples were subjected to treatment according to the following schema: 1st variant – supersaturation and ageing, 2nd variant – supersaturation, cold rolling and ageing. The paper presents the results of microstructure, hardness, and abrasion resistance. The analysis of the wipe profile geometry was realized using a Zeiss LSM 5 Exciter confocal microscope. Cold working of the supersaturated solid solution affects significantly its hardness but the cold plastic deformation causes deterioration of the wear resistance of the finally aged CuTi4 alloy.

  9. The metallurgy of high temperature alloys

    Tien, J. K.; Purushothaman, S.


    Nickel-base, cobalt-base, and high nickel and chromium iron-base alloys are dissected, and their microstructural and chemical components are assessed with respect to the various functions expected of high temperature structural materials. These functions include the maintenance of mechanical integrity over the strain-rate spectrum from creep resistance through fatigue crack growth resistance, and such alloy stability expectations as microstructural coarsening resistance, phase instability resistance and oxidation and corrosion resistance. Special attention will be given to the perennial conflict and trade-off between strength, ductility and corrosion and oxidation resistance. The newest developments in the constitution of high temperature alloys will also be discussed, including aspects relating to materials conservation.

  10. General aspects of surface alloy formation

    Bergbreiter, Andreas; Engstfeld, Albert K.; Roetter, Ralf T.; Hoster, Harry E.; Behm, R. Juergen [Institute of Surface Chemistry and Catalysis, Ulm University, D-89069 Ulm (Germany); Berko, Andras


    Surface confined alloys are excellent model systems for studies of structure-property relationships of bimetallic surfaces. They are formed by deposition of a guest metal B onto a substrate A, followed by annealing to a temperature, where place exchange between adatoms and atoms from the underlying surface layer becomes possible and diffusion into the bulk is sufficiently slow. We exemplarily confirmed by scanning tunneling microscopy and Auger electron spectroscopy for PtRu/Ru(0001), PdRu/Ru(0001), AuPt/Pt(111), AgPt/Pt(111), and AgPd/Pd(111), surface alloys are obtained for systems where metal B has a negative surface segregation energy within metal A. By exchanging A and B, however, AB surface alloys are most likely overgrown by metal B, which we demonstrate for RuPt/Pt(111) in comparison to PtRu/Ru(0001).

  11. Irradiation creep of vanadium-base alloys

    Tsai, H.; Billone, M.C.; Strain, R.V.; Smith, D.L. [Argonne National Lab., IL (United States); Matsui, H. [Tohoku Univ. (Japan)


    A study of irradiation creep in vanadium-base alloys is underway with experiments in the Advanced Test Reactor (ATR) and the High Flux Isotope Reactor (HFIR) in the United States. Test specimens are thin-wall sealed tubes with internal pressure loading. The results from the initial ATR irradiation at low temperature (200--300 C) to a neutron damage level of 4.7 dpa show creep rates ranging from {approx}0 to 1.2 {times} 10{sup {minus}5}/dpa/MPa for a 500-kg heat of V-4Cr-4Ti alloy. These rates were generally lower than reported from a previous experiment in BR-10. Because both the attained neutron damage levels and the creep strains were low in the present study, however, these creep rates should be regarded as only preliminary. Substantially more testing is required before a data base on irradiation creep of vanadium alloys can be developed and used with confidence.

  12. Joining Techniques for Ferritic ODS Alloys

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


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

  13. Microstructural and magnetic behavior of an equiatomic NiCoAlFe alloy prepared by mechanical alloying

    Gómez-Esparza, C.D.; Baldenebro-López, F.J.; Santillán-Rodríguez, C.R.; Estrada-Guel, I.; Matutes-Aquino, J.A.; Herrera-Ramírez, J.M., E-mail:; Martínez-Sánchez, R.


    Highlights: • Equiatomic NiCoAlFe powder alloys were synthesized by mechanical alloying. • The nanocrystalline alloys were characterized after milled and annealed conditions. • In alloyed and annealed powders, only BCC and FCC structure phases were observed. • Magnetic properties are strongly affected by the phases formed after annealing. - Abstract: Equiatomic NiCoAlFe powder alloys were synthesized by mechanical alloying. The microstructural evolution of the mechanically alloyed powders at different times was followed with X-ray diffraction and scanning electron microscopy. The as-mechanically alloyed powders were subjected to a rapid annealing treatment at 1273 K and 1473 K during 3 min in vacuum. X-ray diffraction studies show the structure of both, the as-mechanically alloyed and annealed powders, consisted in a mixture of nanocrystalline simple phases (FCC + BCC). Crystallite size, after annealing, still remained in nanoscale. Coercivity increased due to the decrease in crystallite size and because of the defects caused by mechanical alloying in the as-mechanically alloyed samples; then coercivity decreased due to the phenomenon of random magnetic anisotropy and tended to stabilize with longer alloying times. A similar behavior was observed in annealed samples at 1273 K. However, random magnetic anisotropy was not observed after annealing at 1473 K because crystals with larger sizes were produced, and a steady increase in coercivity was observed.

  14. Fast LIBS Identification of Aluminum Alloys

    Tawfik W.


    Full Text Available Laser-induced breakdown spectroscopy (LIBS has been applied to analysis aluminum alloy targets. The plasma is generated by focusing a 300 mJ pulsed Nd: YAG laser on the target in air at atmospheric pressure. Such plasma emission spectrum was collected using a one-meter length wide band fused-silica optical fiber connected to a portable Echelle spectrometer with intensified CCD camera. Spectroscopic analysis of plasma evolution of laser produced plasmas has been characterized in terms of their spectra, electron density and electron temperature assuming the LTE and optically thin plasma conditions. The LIBS spectrum was optimized for high S/N ratio especially for trace elements. The electron temperature and density were determined using the emission intensity and stark broadening, respectively, of selected aluminum spectral lines. The values of these parameters were found to change with the aluminum alloy matrix, i.e. they could be used as a fingerprint character to distinguish between different aluminum alloy matrices using only one major element (aluminum without needing to analysis the rest of elements in the matrix. Moreover, It was found that the values of T e and N e decrease with increasing the trace elements concentrations in the aluminum alloy samples. The obtained results indicate that it is possible to improve the exploitation of LIBS in the remote on-line industrial monitoring application, by following up only the values of T e and N e for aluminum in aluminum alloys as a marker for the correct alloying using an optical fiber probe.

  15. Irradiation creep of dispersion strengthened copper alloy

    Pokrovsky, A.S.; Barabash, V.R.; Fabritsiev, S.A. [and others


    Dispersion strengthened copper alloys are under consideration as reference materials for the ITER plasma facing components. Irradiation creep is one of the parameters which must be assessed because of its importance for the lifetime prediction of these components. In this study the irradiation creep of a dispersion strengthened copper (DS) alloy has been investigated. The alloy selected for evaluation, MAGT-0.2, which contains 0.2 wt.% Al{sub 2}O{sub 3}, is very similar to the GlidCop{trademark} alloy referred to as Al20. Irradiation creep was investigated using HE pressurized tubes. The tubes were machined from rod stock, then stainless steel caps were brazed onto the end of each tube. The creep specimens were pressurized by use of ultra-pure He and the stainless steel caps subsequently sealed by laser welding. These specimens were irradiated in reactor water in the core position of the SM-2 reactors to a fluence level of 4.5-7.1 x 10{sup 21} n/cm{sup 2} (E>0.1 MeV), which corresponds to {approx}3-5 dpa. The irradiation temperature ranged from 60-90{degrees}C, which yielded calculated hoop stresses from 39-117 MPa. A mechanical micrometer system was used to measure the outer diameter of the specimens before and after irradiation, with an accuracy of {+-}0.001 mm. The irradiation creep was calculated based on the change in the diameter. Comparison of pre- and post-irradiation diameter measurements indicates that irradiation induced creep is indeed observed in this alloy at low temperatures, with a creep rate as high as {approx}2 x 10{sup {minus}9}s{sup {minus}1}. These results are compared with available data for irradiation creep for stainless steels, pure copper, and for thermal creep of copper alloys.

  16. Characterization for Fusion Candidate Vanadium Alloys

    T. Muroga; T. Nagasaka; J. M. Chen; Z. Y. Xu; Q. Y. Huang; y. C. Wu


    This paper summarizes recent achievements in the characterization of candidate vanadium alloys obtained for fusion in the framework of the Japan-China Core University Program.National Institute for Fusion Science (NIFS) has a program of fabricating high-purity V-4Cr4Ti alloys. The resulting products (NIFS-HEAT-1,2), were characterized by various research groups in the world including Chinese partners. South Western Institute of Physics (SWIP) fabricated a new V-4Cr-4Ti alloy (SWIP-Heat), and carried out a comparative evaluation of hydrogen embrittlement of NIFS-HEATs and SWIP-Heat. The tensile test of hydrogen-doped alloys showed that the NIFS-HEAT maintained the ductility to relatively high hydrogen levels.The comparison of the data with those of previous studies suggested that the reduced oxygen level in the NIFS-HEATs should be responsible for the increased resistance to hydrogen embrittlement.Based on the chemical analysis data of NIFS-HEATs and SWIP-Heats, neutron-induced activation was analyzed in Institute of Plasma Physics (IPP-CAS) as a function of cooling time after the use in the fusion first wall. The results showed that the low level of Co dominates the activity up to 50 years followed by a domination of Nb or Nb and Al in the respective alloys. It was suggested that reduction of Co and Nb, both of which are thought to have been introduced via cross-contamination into the alloys from the molds used should be crucial for reducing further the activation.

  17. Creep behavior of Zr-Nb alloys

    Suh, Yong Chan; Kim, Young Suk; Cheong, Yong Mu; Kwon, Sang Chul; Kim, Sung Soo; Choo, Ki Nam [Korea Atomic Energy Research Institute, Taejeon (Korea)


    The creep characteristics of Zirconium alloy is affected by several parameters. Out-reactor creep increases both with an increasing amount of Nb, Sn and S contained in alpha-Zr and decreases with the increasing volume of alpha-Zr. Especially, the creep of Zr-2.5Nb alloy depends on the solubility of Nb in alpha-Zr, which is associated with the decomposition of beta-Zr. Since Zr of the hcp structure is strongly anisotropic, it shows the characteristics of texture and results in the anisotropy of creep. Due to the circumferential texture of Zr-2.5%Nb alloy (CANDU Pressure tube), the longitudinal slip is easier than the circumferential one, resulting in the high creep rate. The irradiation creep also increases with increasing neutron fluence. The neutron irradiation increases the strength of the zirconium alloys but decreases their creep strength. In contrast to the out-reactor creep, the irradiation creep is little sensitive to temperature, resulting in the lower activation energy. The most important factor to affect the in-reactor and out-reactor creep of niobium containing alloys seems to be the solution hardening by Nb or Sn which is soluble in alpha-zirconium and the texture as well. Irradiation growth is the mechanism which is caused only by the irradiation. It becomes saturated at lower fluence than the critical fluence but beyond it, shows the break-away growth. The onset of accelerated irradiation growth corresponds with the c-dislocation loop formation, though its mechanism needs better understanding. Generally, the irradiation growth of Zr-Nb alloys increases with an increase in fluence, cold working, dislocation, density and temperature, and with a decrease in the grain size. 141 refs., 59 figs., 10 tabs. (Author)

  18. Modeling of Alternative Compositions of Recycled Wrought Aluminum Alloys

    Kevorkijan, Varužan


    Nowadays, a significant part of postconsumed wrought aluminum scrap is still used for the production of comparatively cheaper cast alloys, in that way losing an important part of the potential added value. The share of postconsumed scrap in wrought aluminum alloys could be increased either by sorting to fractions with the required chemical composition and/or by broadening the standard compositional tolerance limits of alloying elements. The first solution requires hand or automatic sorting of postconsumed scrap as alloys or groups of alloys to the degree of separation sufficient to enable the blending of standard compositions of wrought alloys; the second solution is much more radical, predicting changes in the existing standards for wrought aluminum alloys toward nonstandard alloys but yet having properties acceptable for customers. In this case, the degree of separation of incoming postconsumed scrap required is much less demanding. The model presented in this work enables the design of optimal (standard and nonstandard recycling-friendly) compositions and properties of wrought aluminum alloys with significantly increased amounts of postconsumed scrap. The following two routes were modeled in detail: (I) the blending of standard and nonstandard compositions of wrought aluminum alloys starting from postconsumed aluminum scrap sorted to various degrees simulated by the model and (II) changing the initial standard composition of wrought aluminum alloys to nonstandard "recycling-friendly" ones, with broader concentration tolerance limits of alloying elements and without influencing the selected alloy properties, specified in advance. The applied algorithms were found to be very useful in the industrial design of both procedures: (I) the computation of the required chemical composition of the scrap streams obtained by sorting (or, in other words, the postconsumed scrap sorting level), necessary for achieving the standard wrought alloy composition and (II) the

  19. Electromagnetic Characterization Of Metallic Sensory Alloy

    Wincheski, Russell A.; Simpson, John; Wallace, Terryl A.; Newman, John A.; Leser, Paul; Lahue, Rob


    Ferromagnetic shape-memory alloy (FSMA) particles undergo changes in both electromagnetic properties and crystallographic structure when strained. When embedded in a structural material, these attributes can provide sensory output of the strain state of the structure. In this work, a detailed characterization of the electromagnetic properties of a FSMA under development for sensory applications is performed. In addition, a new eddy current probe is used to interrogate the electromagnetic properties of individual FSMA particles embedded in the sensory alloy during controlled fatigue tests on the multifunctional material.

  20. Methods for Electrodepositing Composition-Modulated Alloys

    Leisner, Peter; Nielsen, Christian Bergenstof; Tang, Peter Torben;


    Materials exhibiting unique mechanical, physical and chemical properties can be obtained by combining thin layers of different metals or alloys forming a multilayered structure. Two general techniques exist for electrodepositing composition-modulated alloy (CMA) materials; dual-bath and single......-bath plating. For both techniques a number of variations exist. The most suitable technique and variation for the manufacture of a certain CMA material is highly dependent on the metals included in the given CMA system and on the dimensions of the multilayered structure. In this paper, the main principles...

  1. Rapidly solidified titanium alloys by melt overflow

    Gaspar, Thomas A.; Bruce, Thomas J., Jr.; Hackman, Lloyd E.; Brasmer, Susan E.; Dantzig, Jonathan A.; Baeslack, William A., III


    A pilot plant scale furnace was designed and constructed for casting titanium alloy strips. The furnace combines plasma arc skull melting techniques with melt overflow rapid solidification technology. A mathematical model of the melting and casting process was developed. The furnace cast strip of a suitable length and width for use with honeycomb structures. Titanium alloys Ti-6Al-4V and Ti-14Al-21 Nb were successfully cast into strips. The strips were evaluated by optical metallography, microhardness measurements, chemical analysis, and cold rolling.

  2. The irradiation effects on zirconium alloys

    Negut, Gh.; Ancuta, M.; Radu, V.; Ionescu, S.; Stefan, V.; Uta, O.; Prisecaru, I.; Danila, N.


    Pressure tube samples were irradiated under helium atmosphere in the TRIGA Steady State Research and Material Test Reactor of the Romanian Institute for Nuclear Research (INR). These samples are made of the Zr-2.5%Nb alloy used as structural material for the CANDU Romanian power reactors. After irradiation, mechanical tests were performed in the Post Irradiation Examination Laboratory (PIEL) to study the influence of irradiation on zirconium alloys mechanical behaviour. The tensile test results were used for structural integrity assessment. Results of the tests are presented. The paper presents, also, pressure tube structural integrity assessment.

  3. Exchange bias effect in alloys and compounds.

    Giri, S; Patra, M; Majumdar, S


    The phenomenology of exchange bias effects observed in structurally single-phase alloys and compounds but composed of a variety of coexisting magnetic phases such as ferromagnetic, antiferromagnetic, ferrimagnetic, spin-glass, cluster-glass and disordered magnetic states are reviewed. The investigations on exchange bias effects are discussed in diverse types of alloys and compounds where qualitative and quantitative aspects of magnetism are focused based on macroscopic experimental tools such as magnetization and magnetoresistance measurements. Here, we focus on improvement of fundamental issues of the exchange bias effects rather than on their technological importance.

  4. Sputtered Clusters from Niobium-Vanadium Alloys

    Schou, Jørgen; Hofer, W. O.


    A series of Nb&z.sbnd;V alloys have been irradiated by 6 keV argon ions. Homonuclear and heteronuclear clusters emitted from these alloys have been studied by means of post-ionization and/or secondary ion mass spectrometry. The intensity of clusters of atomic masses up to approximately 300 amu......-ionized neutrals, the total secondary particle intensity was increased by a factor of 1.5 for clusters up to atomic masses of around 200 amu. Scanning electron microscopy revealed a varied surface topography with large differences from grain to grain for irradiated samples exposed for doses larger than 1018 atoms...

  5. Mechanism of Nickel-Aluminium Alloy Electroplating


    The effect of operating conditions on the aluminium content of Ni-Al alloy deposit and the catalytic function of NaF on electrodeposition in the nonaqueous solution containing aluminium are investigated.The results indicate that the plated aluminuim content will be increased with the rise of current density in a given range.When the current density is 2.5A/dm2,nickle-aluminium alloy containing 13.1 wt% aluminium will be deposited.The plated aluminium content will be increased by 2wt% as 0.1mol/L NaF is added to the bath.

  6. Transparent Analogs for Alloy Phase Studies

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


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

  7. Nodular Corrosion Characteristics of Zirconium Alloys

    Kim, Hyun Gil; Jeong, Y. H.; Park, S. Y.; Lee, D. J


    This study was reported the effect of the nodular corrosion on the nuclear reactor environmental along with metallurgical influence, also suggested experimental scheme related to evaluate nodular corrosion characteristics of Zr-1 Nb alloy. Remedial strategies against the nodular corrosion should firstly develop plan to assess the effect of the water quality condition (Oxygen, Hydrogen) as well as the boiling on the nodular corrosion, secondarily establish plan to control heat treatment process to keep a good resistance on nodular corrosion in Zr-1Nb alloy as former western reactor did.

  8. Precipitation Hardenable High Temperature Shape Memory Alloy

    Noebe, Ronald Dean (Inventor); Draper, Susan L. (Inventor); Nathal, Michael V. (Inventor); Crombie, Edwin A. (Inventor)


    A composition of the invention is a high temperature shape memory alloy having high work output, and is made from (Ni+Pt+Y),Ti(100-x) wherein x is present in a total amount of 49-55 atomic % Pt is present in a total amount of 10-30 atomic %, Y is one or more of Au, Pd. and Cu and is present in a total amount of 0 to 10 atomic %. The alloy has a matrix phase wherein the total concentration of Ni, Pt, and the one or more of Pd. Au, and Cu is greater than 50 atomic %.

  9. New developments in rapidly solidified magnesium alloys

    Das, S.K. [Allied-Signal, Inc., Morristown, NJ (United States); Chang, C.F. [Allied-Signal, Inc., Morristown, NJ (United States); Raybould, D. [Allied-Signal, Inc., Morristown, NJ (United States); King, J.F. [Magnesium Elektron Ltd., Manchester (United Kingdom); Thistlethwaite, S. [Magnesium Elektron Ltd., Manchester (United Kingdom)


    In the present paper, we will examine the new developments in the rapidly solidified Mg-Al-Zn-Nd (EA55RS) alloy. We shall first briefly review the process scale-up currently employed for producing rapidly solidified magnesium alloys in large quantities, and then discuss the effect of billet size and processing parameters on the mechanical properties of various mill product forms such as extrusions and sheets. The superplastic behavior of EA55RS extrusions and rolled sheets are also discussed. Finally, some results on magnesium metal-matrix composites using rapidly solidified EA55RS matrix powders and SiC particulates are presented. (orig.)

  10. Overlay metallic-cermet alloy coating systems

    Gedwill, M. A.; Levine, S. R.; Glasgow, T. K. (Inventor)


    A substrate, such as a turbine blade, vane, or the like, which is subjected to high temperature use is coated with a base coating of an oxide dispersed, metallic alloy (cermet). A top coating of an oxidation, hot corrosion, erosion resistant alloy of nickel, cobalt, or iron is then deposited on the base coating. A heat treatment is used to improve the bonding. The base coating serves as an inhibitor to interdiffusion between the protective top coating and the substrate. Otherwise, the protective top coating would rapidly interact detrimentally with the substrate and degrade by spalling of the protective oxides formed on the outer surface at elevated temperatures.

  11. Mechanoelectrochemical behavior and plasticity of magnesium alloys

    Eliezer, A.; Gutman, E.M.; Abramov, E.; Aghion, E. [Ben-Gurion Univ. of the Negev, Beersheba (Israel). Dept. of Materials Engineering


    The mechanical properties and mechanoelectrochemical effect (the effect of mechanical deformation on the surface electrochemical reactions) were investigated for some Mg-based alloys supposing that aluminum alloying influences them. A simple method of testing mechanoelectrochemical behavior of metals was developed. Potentiostatic polarization measurements on stressed electrode were carried out in chloride electrolyte. The correlation between the mechanoelectrochemical behavior and strain hardening stages is observed during plastic deformation. Maximum mechanoelectrochemical effect is achieved under intense strain hardening in the initial portion of this stage. The experimental observations are explained theoretically. (orig.) 9 refs.

  12. New Stainless Steel Alloys for Low Temperature Surface Hardening?

    Christiansen, Thomas Lundin; Dahl, Kristian Vinter; Somers, Marcel A. J.


    The present contribution showcases the possibility for developing new surface hardenable stainless steels containing strong nitride/carbide forming elements (SNCFE). Nitriding of the commercial alloys, austenitic A286, and ferritic AISI 409 illustrates the beneficial effect of having SNCFE present...... in the stainless steel alloys. The presented computational approach for alloy design enables “screening” of hundreds of thousands hypothetical alloy systems by use of Thermo-Calc. Promising compositions for new stainless steel alloys can be selected based on imposed criteria, i.e. facilitating easy selection...

  13. Mechanical alloying in the Fe-Cu system

    Jiang, Jianzhong; Gente, C.; Bormann, R.


    The studies of mechanical alloying on the Fe-Cu system, as a model system for those with positive heats of mixing, are reviewed. Several problems involved in the mechanical alloying process are discussed. For example, (1) whether alloying occurs on an atomic level; (2) what the solid solubility...... in the Fe-Cu system is; (3) where the positive energy is stored in the alloys; (4) what the decomposition process of the supersaturated alloys is; and (5) what type of magnetic properties the new materials have. The elucidation of these problems will shed light on the understanding of the mechanisms...

  14. Fatigue crack growth behaviour of Al-Li alloys

    Saravanakumar, R.; Ramakrishna, K. S.; Kanna, B. Avinash


    Al-Li alloys are being used in aircraft structures due to its low density and inherent mechanical properties. Fatigue Crack Growth (FCG) resistance is usually high compared to conventional Al-alloys attributed to increased modulus and crack closure. Extensive investigations concern about the FCG resistance and crack closure in Al-Li alloys. The present work reviews the FCG resistance in Al-Li alloys and the mechanisms associated with it. The alloy 8090 is taken for the consideration and sometimes compared with 2024.

  15. Processing of carbon containing gamma titanium aluminide alloys

    Paul, J.D.H.; Froebel, U.; Oehring, M.; Appel, F. [Inst. for Materials Research, GKSS Research Centre, Geesthacht (Germany)


    Gamma-based titanium aluminide alloys have received much attention over the last decade with the intention of being used in turbine applications. In the as-cast state these alloys are relatively brittle when compared with conventional materials. In order to meet property requirements, optimisation of both alloy composition and microstructure are necessary. Alloys based on Ti-45Al-(5-10)Nb (at.%) with carbon additions seems capable of meeting many of the properties necessary for application. This paper addresses the reasons behind the choice of this alloy composition and discusses a relevant processing route. (orig.)

  16. [Corrosion resistance and bond strength of dental alloys].

    Schwickerath, H


    Investigated Ni-alloys, which showed extensive solubility of Ni particles in corrosion bathes due to DIN 13927, also revealed pronounced lost of bond strength to ceramic veneers when immersed into corrosion bathes of equal constitution. Noble metal alloys with a gold concentration more than 50 percent, however, showed no such large lost of bond strength. Pd alloys showed a lost of bond strength which increased with their Ga concentration. Co alloys revealed a behavior similar to the Ni alloys but with no obvious correlation between solubility and lost of bond strength.

  17. Indentation toughness of Mo5Si3-based alloys


    The indentation toughness of Mo5Si3 -based phases was studied with regard to different alloying elements, amount of alloying addition as well as the presence of secondary phases. Cr, Ti, Nb, Ni and Co were added as alloying elements. The results show that the indentation fracture toughness of Mo5Si3 increases with the alloying additions, from 2.4 Mpa *m1/2 for mon olithic to just over 3 Mpa*m1/2 for highly alloyed Mo5Si3. Small volume fractions of brittle secondary phases may have a positive impact on the inde ntation toughness; while larger fractions seems to lower the toughness.

  18. The recasting effects on the high gold dental alloy properties

    Maksimović V.M.


    Full Text Available Noble dental alloys are often reused in dental practice by recasting. The aim of this study was to determine if repeated casting of high gold dental alloys has a detrimental effect on alloy microstructure, type of porosity, structure and microhardness. Results showed that recasting procedure had a strong effect on the change of alloy porosity type. It was also found that alloy microhardness increased with the increase of the number of recasting cycles. At the same time the grain growth and changes of the solid solution phases in the microstructure were observed. [Projekat Ministarstva nauke Republike Srbije, br. III 45012

  19. Magnetic properties of nanostructural γ-Ni-28Fe alloy

    LIU Yin; QIN Xiao-ying; QIU Tai


    Nanostructural γ-Ni-28Fe alloy (nano γ-Ni-28Fe) was successfully prepared by mechanochemical alloying(MCA). The relationship between the microstructure and the synthesis conditions was investigated by using XRD, TEM, SEM as well as BET analyzer. The results show that nano γ-Ni-28Fe alloy is composed ora gamma phase (FCC structure). Its grain size is about 20 nm at reduction temperature below 600 ℃. The magnetic measurements indicate that the saturation magnetization ofnano γ-Ni-28Fe alloy to its decrease of the grain size and chemical composition in nano γ-Ni-28Fe alloy.

  20. Vanadium-base alloys for fusion reactor applications

    Smith, D.L.; Loomis, B.A.; Diercks, D.R.


    Vanadium-base alloys offer potentially significant advantages over other candidate alloys as a structural material for fusion reactor first wall/blanket applications. Although the data base is more limited than that for the other leading candidate structural materials, viz., austenitic and ferritic steels, vanadium-base alloys exhibit several properties that make them particularly attractive for the fusion reactor environment. This paper presents a review of the structural material requirements, a summary of the materials data base for selected vanadium-base alloys, and a comparison of projected performance characteristics compared to other candidate alloys. Also, critical research and development (R and D) needs are defined.

  1. A review on hot tearing of magnesium alloys

    Jiangfeng Song


    Full Text Available Hot tearing is often a major casting defect in magnesium alloys and has a significant impact on the quality of their casting products. Hot tearing of magnesium alloys is a complex solidification phenomenon which is still not fully understood, it is of great importance to investigate the hot tearing behaviour of magnesium alloys. This review attempts to summarize the investigations on hot tearing of magnesium alloys over the past decades. The hot tearing criteria including recently developed Kou's criterion are summarized and compared. The numeric simulation and assessing methods of hot tearing, factors influencing hot tearing, and hot tearing susceptibility (HTS of magnesium alloys are discussed.

  2. Magnetic susceptibility of Dirac fermions, Bi-Sb alloys, interacting Bloch fermions, dilute nonmagnetic alloys, and Kondo alloys

    Buot, Felix A.; Otadoy, Roland E. S.; Rivero, Karla B.


    Wide ranging interest in Dirac Hamiltonian is due to the emergence of novel materials, namely, graphene, topological insulators and superconductors, the newly-discovered Weyl semimetals, and still actively-sought after Majorana fermions in real materials. We give a brief review of the relativistic Dirac quantum mechanics and its impact in the developments of modern physics. The quantum band dynamics of Dirac Hamiltonian is crucial in resolving the giant diamagnetism of bismuth and Bi-Sb alloys. Quantitative agreement of the theory with the experiments on Bi-Sb alloys has been achieved, and physically meaningful contributions to the diamagnetism has been identified. We also treat relativistic Dirac fermion as an interband dynamics in uniform magnetic fields. For the interacting Bloch electrons, the role of translation symmetry for calculating the magnetic susceptibility avoids any approximation to second order in the field. The expressions for magnetic susceptibility of dilute nonmagnetic alloys give a firm theoretical foundation of the empirical formulas used in fitting experimental results. The unified treatment of all the above calculations is based on the lattice Weyl-Wigner formulation of discrete phase-space quantum mechanics. For completeness, the magnetic susceptibility of Kondo alloys is also given since Dirac fermions in conduction band and magnetic impurities exhibit Kondo effect.

  3. Super High Strength Aluminum Alloy Processed by Mechanical Alloying and Hot Extrusion

    Zheng, Ruixiao; Yang, Han; Wang, Zengjie; Wen, Shizhen; Liu, Tong; Ma, Chaoli

    Nanostructure strengthened aluminum alloy was prepared by powder metallurgic technology. The rapid solidification Al-Cu-Mg alloy powder was used in this study. To obtain nanostructure, the commercial powder was intensely milled under certain ball milling conditions. The milled powder was compacted first by cold isostatic pressing (CIP) at a compressive pressure of 300MPa, and then extruded at selected temperature for several times to obtain near full density material. Microstructure and mechanical properties of the extruded alloy were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and mechanical tests. It is revealed that the compressive strength of extruded alloy is higher than 800MPa. The strengthening mechanism associated with the nanostructure is discussed.

  4. Structure and phase transformations in Fe-Ni-Mn alloys nanostructured by mechanical alloying

    Pustov, L.Yu., E-mail: pustov@mail.r [Moscow State Institute of Steel and Alloys, Leninsky prosp. 4, Moscow 119049 (Russian Federation); Tcherdyntsev, V.V.; Abdulhalikov, Sh.M.; Kaloshkin, S.D.; Shelekhov, E.V. [Moscow State Institute of Steel and Alloys, Leninsky prosp. 4, Moscow 119049 (Russian Federation); Estrin, E.I. [Central Research Inst. of Ferrous Metallurgy, 2nd Baumanskaya st, 9/23, Moscow 107005 (Russian Federation); Baldokhin, Yu.V. [Institute of Chemical Physics, Russian Academy of Sciences, Kosygina str., 4, Moscow 117334 (Russian Federation)


    Ternary Fe{sub 86}Ni{sub x}Mn{sub 14-x} alloys, where x = 0, 2, 4, 6, 8, 10, 12, 14, 16 at.%, were prepared by the mechanical alloying (MA) of elemental powders in a high-energy planetary ball mill. X-ray diffraction analysis and Moessbauer spectroscopy were used to investigate the structure and phase composition of samples. Thermo-magnetic measurements were used to study the phase transformation temperatures. The MA results in the formation of bcc alpha-Fe and fcc gamma-Fe based solid solutions, the hcp phase was not observed after MA. As-milled alloys were annealed with further cooling to ambient or liquid nitrogen temperatures. A significant decrease in martensitic points for the MA alloys was observed that was attributed to the nanocrystalline structure formation.

  5. Structure of nanocomposites of Al–Fe alloys prepared by mechanical alloying and rapid solidification processing

    S S Nayak; B S Murty; S K Pabi


    Structures of Al-based nanocomposites of Al–Fe alloys prepared by mechanical alloying (MA) and subsequent annealing are compared with those obtained by rapid solidification processing (RSP). MA produced only supersaturated solid solution of Fe in Al up to 10 at.% Fe, while for higher Fe content up to 20 at.% the nonequilibrium intermetallic Al5Fe2 appeared. Subsequent annealing at 673 K resulted in more Al5Fe2 formation with very little coarsening. The equilibrium intermetallics, Al3Fe (Al13Fe4), was not observed even at this temperature. In contrast, ribbons of similar composition produced by RSP formed fine cellular or dendritic structure with nanosized dispersoids of possibly a nano-quasicrystalline phase and amorphous phase along with -Al depending on the Fe content in the alloys. This difference in the product structure can be attributed to the difference in alloying mechanisms in MA and RSP.




    Full Text Available Three types of zirconium base alloy were evaluated to study how their work hardening behavior is affected by alloy composition. Repeated-tensile tests (5% elongation at each test were performed at room temperature at a strain rate of 1.7 × 10−3 s−1 for the alloys, which were initially controlled for their microstructure and texture. After considering the yield strength and work hardening exponent (n variations, it was found that the work hardening behavior of the zirconium base alloys was affected more by the Nb content than the Sn content. The facture mode during the repeated tensile test was followed by the slip deformation of the zirconium structure from the texture and microstructural analysis.

  7. Role of alloying additions on the properties of Cu–Al–Mn shape memory alloys

    Dasgupta, Rupa, E-mail:; Jain, Ashish Kumar; Kumar, Pravir; Hussain, Shahadat; Pandey, Abhishek


    Highlights: • Cu based SMAs with high transition temperature could be made using LM route. • The properties depend on alloying composition. • Property characterisation establishes feasibility of making SMAs. - Abstract: The effect of alloying seven different elements [Zn, Si, Fe, Ni, Mg, Cr and Ti] on the microstructure, hardness, phase precipitation and transformation temperature in a Cu–12.5Al–5Mn alloy with a view to possible improvements as a result of these additions is the focus of the reported study. The base alloy has been chosen keeping in mind its ability to exhibit shape memory properties and improved ductility over other Cu-based SMAs. The objective was to ascertain changes or improvements attained due to the individual tertiary additions. The samples were prepared through liquid metallurgy route using pure copper, aluminum, manganese and the respective quaternary alloying elements in right quantities to weigh 1000 g of the alloy in total and were melted together. Samples from the cast alloys were subject to homogenisation treatment at 200 °C for 2 h in a muffle furnace and furnace cooled. Samples from the homogenised alloys were heated and held for 2 h at 920 °C followed by ice quenching to obtain the desired martensitic structure for shape memory behaviour. The alloys in the cast, homogenised and quenched conditions were metallographically polished to observe the martensitic phase formation mainly in quenched samples which is a pre requisite for exhibiting shape memory properties in these alloys. X-ray Diffraction studies were carried out on the cast and quenched samples using Cu Kα target; and the phases identified indicate martensitic phase precipitation; however in some cases the precipitation is incomplete. Differential Scanning Calorimetric [DSC] studies were carried out on quenched samples from room temperature to 600 °C maintaining a constant rate of 10 °C/min. Results indicate clear transformation peaks in all the samples which

  8. Corrosion behavior of friction stir welded AZ31B Mg alloy - Al6063 alloy joint

    B. Ratna Sunil


    Full Text Available In the present work, AZ31B Mg alloy and Al6063 alloy-rolled sheets were successfully joined by friction stir welding. Microstructural studies revealed a sound joint with good mechanical mixing of both the alloys at the nugget zone. Corrosion performance of the joint was assessed by immersing in 3.5% NaCl solution for different intervals of time and the corrosion rate was calculated. The joint has undergone severe corrosion attack compared with both the base materials (AZ31B and Al6063 alloys. The predominant corrosion mechanism behind the high corrosion rate of the joint was found to be high galvanic corrosion. From the results, it can be suggested that the severe corrosion of dissimilar Mg–Al joints must be considered as a valid input while designing structures intended to work in corroding environment.

  9. Synthesis of Al/Al sub 3 Ti two-phase alloys by mechanical alloying

    Srinivasan, S.; Chen, S.R.; Schwarz, R.B.


    We have mechanically alloyed mixtures of elemental powders to prepare fine-grain two-phase A1/A1{sub 3}Ti powders at the compositions A1-20at% Ti and Al-10at% Ti. Hexane was used to prevent agglomeration of the powder during MA. Carbon from the decomposition of the hexane was incorporated in the powder. It reacted with Ti to form a fine dispersion of carbides in the final hot-pressed compact. We consolidated the mechanically alloyed powders by hot-pressing. Yield strength and ductility were measured in compression. At 25{degree}C, the compressive yield strengths were 1.25 and 0.6 GPa for the A1-20at% Ti and Al-10at% Ti alloys, respectively. The ductility of the A1-10at% Ti alloy exceeded 20% for 25 < T < 500{degree}C. 25 refs., 6 figs.

  10. Dispersoid reinforced alloy powder and method of making

    Anderson, Iver E.; Terpstra, Robert L.


    A method of making dispersion-strengthened alloy particles involves melting an alloy having a corrosion and/or oxidation resistance-imparting alloying element, a dispersoid-forming element, and a matrix metal wherein the dispersoid-forming element exhibits a greater tendency to react with a reactive species acquired from an atomizing gas than does the alloying element. The melted alloy is atomized with the atomizing gas including the reactive species to form atomized particles so that the reactive species is (a) dissolved in solid solution to a depth below the surface of atomized particles and/or (b) reacted with the dispersoid-forming element to form dispersoids in the atomized particles to a depth below the surface of said atomized particles. The atomized alloy particles are solidified as solidified alloy particles or as a solidified deposit of alloy particles. Bodies made from the dispersion strengthened alloy particles, deposit thereof, exhibit enhanced fatigue and creep resistance and reduced wear as well as enhanced corrosion and/or oxidation resistance at high temperatures by virtue of the presence of the corrosion and/or oxidation resistance imparting alloying element in solid solution in the particle alloy matrix.

  11. Phase evolution and alloying mechanism of titanium aluminide nanoparticles

    Luo, J.S.; Li, K.; Li, X.B. [Research Center of Laser Fusion, Science and Technology on Plasma Physics Laboratory, China Academy of Engineering Physics, Mianyang 621900 (China); Shu, Y.J. [Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang 621900 (China); Tang, Y.J., E-mail: [Research Center of Laser Fusion, Science and Technology on Plasma Physics Laboratory, China Academy of Engineering Physics, Mianyang 621900 (China)


    Highlights: • An evolution of phase composition of TiAl alloy nanoparticles was investigated. • An alloying mechanism was analyzed according to the variation of phase composition. • The alloying reaction was possible to perform between the small clusters of Ti and Al. • The alloying product is determined by the temperature of Ti and Al small clusters. • The alloying mechanism can be explained based on Gibbs free energy of alloying reaction. - Abstract: The evolution of phase composition of titanium aluminide nanoparticles synthesized by the flow-levitation method was systematically investigated by adjustment of the evaporating temperature of the mixed metallic droplet and the X-ray diffraction spectrum. Their alloying mechanism was analyzed according to the variation of phase composition. ε(h, l)-TiAl{sub 3,} γ-TiAl and α{sub 2}-Ti{sub 3}Al phases are gradually formed in TiAl alloy nanoparticles with the increasing of evaporating temperature of the mixed droplet. The alloying reaction is possible to perform between the small clusters of Ti and Al during the cooling process with high cooling rate. And the alloying mechanism can be explained based on the Gibbs free energy of alloying reaction of Ti and Al small clusters.

  12. Microstructure and properties of 2618-Ti heat resistant aluminum alloy

    王建华; 易丹青; 王斌


    The mechanical properties of alloy 2618 with 0.5%(mass fraction) titanium and its microstructures in different states such as as-cast and quenching-aging were investigated. Titanium was added into the alloy with Al-5%Ti master alloy that was extruded severely. Al3Ti particles in the microstructure of cast alloy 2618-Ti are very small because those of master alloy are also small. When titanium is used as an alloying element, it does not affect the morphology of Al9FeNi phase in cast alloy, but decreases the grain size of as-cast alloy remarkably. The grain size of quenching-aging alloy 2618 decreases apparently due to the existence of a great deal of dispersive Al3Ti particles. Adding 0.5%Ti has no effect on the room temperature tensile properties of alloy 2618, but apparently increases the elevated temperature instantaneous tensile properties and that of the alloy which is exposed at 250 ℃ for 100 h.

  13. Dispersoid reinforced alloy powder and method of making

    Anderson, Iver E.; Terpstra, Robert L.


    A method of making dispersion-strengthened alloy particles involves melting an alloy having a corrosion and/or oxidation resistance-imparting alloying element, a dispersoid-forming element, and a matrix metal wherein the dispersoid-forming element exhibits a greater tendency to react with a reactive species acquired from an atomizing gas than does the alloying element. The melted alloy is atomized with the atomizing gas including the reactive species to form atomized particles so that the reactive species is (a) dissolved in solid solution to a depth below the surface of atomized particles and/or (b) reacted with the dispersoid-forming element to form dispersoids in the atomized particles to a depth below the surface of said atomized particles. The atomized alloy particles are solidified as solidified alloy particles or as a solidified deposit of alloy particles. Bodies made from the dispersion strengthened alloy particles, deposit thereof, exhibit enhanced fatigue and creep resistance and reduced wear as well as enhanced corrosion and/or oxidation resistance at high temperatures by virtue of the presence of the corrosion and/or oxidation resistance imparting alloying element in solid solution in the particle alloy matrix.

  14. In vitro and in vivo studies on biodegradable magnesium alloy

    Lida Hou


    Full Text Available The microstructure, mechanical property, electrochemical behavior and biocompatibility of magnesium alloy (BioDe MSM™ were studied in the present work. The experimental results demonstrated that grain refining induced by extrusion improves the alloy strength significantly from 162 MPa for the as-cast alloy to 241 MPa for the as-extruded one. The anticorrosion properties of the as-extruded alloy also increased. Furthermore, the hemolysis ratio was decreased from 4.7% for the as-cast alloy to 2.9% for the as-extruded one, both below 5%. BioDe MSM™ alloy shows good biocompatibility after being implanted into the dorsal muscle and the femoral shaft of the New Zealand rabbit, respectively, and there are no abnormalities after short-term implantation. In vivo observation indicated that the corrosion rate of this alloy varies with different implantation positions, with higher degradation rate in the femur than in the muscle.

  15. Grain Refinement of Permanent Mold Cast Copper Base Alloys

    M.Sadayappan; J.P.Thomson; M.Elboujdaini; G.Ping Gu; M. Sahoo


    Grain refinement is a well established process for many cast and wrought alloys. The mechanical properties of various alloys could be enhanced by reducing the grain size. Refinement is also known to improve casting characteristics such as fluidity and hot tearing. Grain refinement of copper-base alloys is not widely used, especially in sand casting process. However, in permanent mold casting of copper alloys it is now common to use grain refinement to counteract the problem of severe hot tearing which also improves the pressure tightness of plumbing components. The mechanism of grain refinement in copper-base alloys is not well understood. The issues to be studied include the effect of minor alloy additions on the microstructure, their interaction with the grain refiner, effect of cooling rate, and loss of grain refinement (fading). In this investigation, efforts were made to explore and understand grain refinement of copper alloys, especially in permanent mold casting conditions.

  16. High strength beta titanium alloys: New design approach

    Okulov, I.V., E-mail: [IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); TU Dresden, Institut für Werkstoffwissenschaft, D-01062 Dresden (Germany); Wendrock, H. [IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); Volegov, A.S. [IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); Institute of Natural Sciences, Ural Federal University, 620000 Ekaterinburg (Russian Federation); Attar, H. [IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); School of Engineering, Edith Cowan University, 270 Joondalup Drive, Joondalup, Perth, WA 6027 (Australia); Kühn, U. [IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); Skrotzki, W. [TU Dresden, Institut für Strukturphysik, D-01062 Dresden (Germany); Eckert, J. [IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); TU Dresden, Institut für Werkstoffwissenschaft, D-01062 Dresden (Germany)


    A novel approach for development of high strength and ductile beta titanium alloys was proposed and successfully applied. The microstructure of the designed alloys is fully composed of a bcc β-Ti phase exhibiting dendritic morphology. The new Ti{sub 68.8}Nb{sub 13.6}Cr{sub 5.1}Co{sub 6}Al{sub 6.5} (at%) alloy (BETA{sup tough} alloy) exhibits a maximum tensile strength of 1290±50 MPa along with 21±3% of fracture strain. The specific energy absorption value upon mechanical deformation of the BETA{sup tough} alloy exceeds that of Ti-based metallic glass composites and commercial high strength Ti-based alloys. The deformation behavior of the new alloys was correlated with their microstructure by means of in-situ studies of the microstructure evolution upon tensile loading in a scanning electron microscope.

  17. Fabric cutting application of FeAl-based alloys

    Sikka, V.K.; Blue, C.A. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.; Sklad, S.P. [Univ. of Virginia, Charlottesville, VA (United States); Deevi, S.C. [Philip Morris U.S.A., Richmond, VA (United States); Shih, H.R. [Jackson State Univ., MS (United States)


    Four intermetallic-based alloys were evaluated for cutting blade applications. These alloys included Fe{sub 3}Al-based (FAS-II and FA-129), FeAl-based (PM-60), and Ni{sub 3}Al-based (IC-50). These alloys were of interest because of their much higher work-hardening rates than the conventionally used carbon and stainless steels. The FeAl-based PM-60 alloy was of further interest because of its hardening possibility through retention of vacancies. The vacancy retention treatment is much simpler than the heat treatments used for hardening of steel blades. Blades of four intermetallic alloys and commercially used M2 tool steel blades were evaluated under identical conditions to cut two-ply heavy paper. Comparative results under identical conditions revealed that the FeAl-based alloy PM-60 outperformed the other intermetallic alloys and was equal to or somewhat better than the commercially used M2 tool steel.

  18. Titanium Alloys and Processing for High Speed Aircraft

    Brewer, William D.; Bird, R. Keith; Wallace, Terryl A.


    Commercially available titanium alloys as well as emerging titanium alloys with limited or no production experience are being considered for a variety of applications to high speed commercial aircraft structures. A number of government and industry programs are underway to improve the performance of promising alloys by chemistry and/or processing modifications and to identify appropriate alloys and processes for specific aircraft structural applications. This paper discusses some of the results on the effects of heat treatment, service temperatures from - 54 C to +177 C, and selected processing on the mechanical properties of several candidate beta and alpha-beta titanium alloys. Included are beta alloys Timetal 21S, LCB, Beta C, Beta CEZ, and Ti-10-2-3 and alpha-beta alloys Ti-62222, Ti-6242S, Timetal 550, Ti-62S, SP-700, and Corona-X. The emphasis is on properties of rolled sheet product form and on the superplastic properties and processing of the materials.

  19. Development of Lead-Free Copper Alloy-Graphite Castings

    Rohatgi, P.K. [Univ. of Wisconsin-Milwaukee (US)


    In this project, graphite is used as a substitute for lead in order to maintain the machinability of plumbing components at the level of leaded brass. Graphite dispersed in Cu alloy was observed to impart good machinability and reduce the sizes of chips during machining of plumbing components in a manner similar to lead. Copper alloys containing dispersed graphite particles could be successfully cast in several plumbing fixtures which exhibited acceptable corrosion rate, solderability, platability, and pressure tightness. The power consumption for machining of composites was also lower than that of the matrix alloy. In addition, centrifugally cast copper alloy cylinders containing graphite particles were successfully made. These cylinders can therefore be used for bearing applications, as substitutes for lead-containing copper alloys. The results indicate that copper graphite alloys developed under this DOE project have a great potential to substitute for lead copper alloys in both plumbing and bearing applications.

  20. In vitro and in vivo studies on biodegradable magnesium alloy

    Lida Hou; Zhen Li; Yu Pan; Li Du; Xinlin Li; Yufeng Zheng; Li Li


    The microstructure, mechanical property, electrochemical behavior and biocompatibility of magnesium alloy (BioDe MSM™) were studied in the present work. The experimental results demonstrated that grain refining induced by extrusion improves the alloy strength significantly from 162 MPa for the as-cast alloy to 241 MPa for the as-extruded one. The anticorrosion properties of the as-extruded alloy also increased. Furthermore, the hemolysis ratio was decreased from 4.7%for the as-cast alloy to 2.9%for the as-extruded one, both below 5%. BioDe MSM™alloy shows good biocompatibility after being implanted into the dorsal muscle and the femoral shaft of the New Zealand rabbit, respectively, and there are no abnormalities after short-term implantation. In vivo observation indicated that the corrosion rate of this alloy varies with different implantation positions, with higher degradation rate in the femur than in the muscle.

  1. Development of Zr alloys - Fabrication of Zr-Nb alloy used in PHWRs

    Lee, Kang In; Kim, Won Baek; Choi, Guk Sun; Lee, Chul Kyung; Jang, Dae Kyu; Seo, Chang Yeol; Sim, Kun Joo; Lee, Jae Cheon [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)


    The manufacture of Zr-Nb alloy ingot by EB melting process is carried out to meet the chemical composition and mechanical and property specifications and to ensure that the ingots are free of unacceptable defects through this study. It was established that Zr-Nb alloy was made by EB melting technique including the control of adding elements, melting power and melting and cast device. 28 refs., 13 tabs., 26 figs., 23 ills. (author)

  2. Improvement in grain refinement efficiency of Mg–Zr master alloy for magnesium alloy by friction stir processing

    Wang, Chengqi; Sun, Ming; Zheng, Feiyan; Peng, Liming; Ding, Wenjiang


    Previous studies have proved that the zirconium (Zr) alloying and grain refining performance of a Mg–Zr master alloy on Mg alloy is closely related to the distribution of Zr particle size, and a Mg–Zr master alloy with more Zr particles in size range of 1–5 μm exhibits a better refining efficiency. In this paper, friction stir processing (FSP) was used to modify the Zr particles size distribution of a commercially available Mg–30 wt.%Zr master alloy, and the subsequent grain refinement abilit...

  3. Development of Strip Casting Technology in Rare Earth Permanent Magnet Alloys and Hydrogen Storage Alloys in China

    Han Weiping; Guo Binglin; Yu Xiaojun; Zhu Jinghan; Cheng Xinghua


    The SC technique is now being applied widely in material preparation, especially in rare earth functional materials in virtue of its advanced process and high performance product. The applications of SC technique in rare earth permanent magnet alloys and hydrogen storage alloys were analyzed integrative, on the basis of summary of SC technique development in this paper. The paper mainly includes development history of SC technology, effect of SC technology on alloy microstructure, application of SC technology in RE storage hydrogen alloy and sintered Nd-Fe-B alloy, development of SC equipment and SC product industry. At the same time, the paper points out the existing problem of SC products.

  4. Effect of mechanical alloying on FeCrC reinforced Ni alloys

    Yilmaz, S. Osman [Univ. of Namik Kemal, Tekirdag (Turkey); Teker, Tanju [Adiyaman Univ. (Turkey). Dept. of Metallurgical and Materials Engineering; Demir, Fatih [Batman Univ. (Turkey)


    Mechanical alloying (MA) is a powder metallurgy processing technique involving cold welding, fracturing and rewelding of powder particles in a high-energy ball mill. In the present study, the intermetallic matrix composites (IMCs) of Ni-Al reinforced by M{sub 7}C{sub 3} were produced by powder metallurgical routes via solid state reaction of Ni, Al and M{sub 7}C{sub 3} particulates by mechanical alloying processes. Ni, Al and M{sub 7}C{sub 3} powders having 100 μm were mixed, mechanical alloyed and the compacts were combusted in a furnace. The mechanically alloyed (MAed) powders were investigated by X-ray diffraction (XRD), microhardness measurement, optic microscopy (OM), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The presence of the carbides depressed the formation of unwanted NiAl intermetallic phases. The mechanical alloyed M{sub 7}C{sub 3} particles were unstable and decomposed partially within the matrix during alloying and sintering, and the morphology of the composites changed with the dissolution ratio of M{sub 7}C{sub 3} and sintering temperature.

  5. The open-circuit ennoblement of alloy C-22 and other Ni-Cr-Mo alloys

    Lloydis, A. C.; Noël, J. J.; Shoesmith, D. W.; McIntyre, N. S.


    The open-circuit corrosion and anodic oxidation behavior of the C-series of Ni-Cr-Mo alloys (C-4, C-276, C-2000, and C-22) and alloy 625 have been studied at 25°C and 75°C in 1.0 mol·L-1 NaCl+1.0 mol·L-1 H2SO4. A combination of open-circuit potential, potentiostatic polarization, and electrochemical impedance spectroscopy were employed in the study. The composition of the films formed was determined by x-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry. Passive oxide film resistances increase and defect oxide film concentrations decrease as films thicken and chromium and molybdenum segregate to the alloy/oxide and oxide/solution interfaces, respectively. The high-chromium alloys exhibit higher film resistances and lower film defect concentrations consistent with the more positive potentials observed on these alloys. The results show that the observed ennoblement in corrosion potentials with time is coupled to the Cr/Mo segregation process and the suppression of defect injection at the alloy/oxide interface. By all measures, C-22 exhibited the best passive properties.

  6. Laser alloying of Ti–Si compound coating on Ti–6Al–4V alloy for the improvement of bioactivity

    Wu, Y. [State Key Laboratory of Material Processing and Die and Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, Wuhan University, Wuhan 430079 (China); Wang, A.H., E-mail: [State Key Laboratory of Material Processing and Die and Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Zhang, Z.; Zheng, R.R. [State Key Laboratory of Material Processing and Die and Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Xia, H.B.; Wang, Y.N. [The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, Wuhan University, Wuhan 430079 (China)


    Laser alloying of Ti–Si compound coating on Ti–6Al–4V alloy is carried out by a pulsed Nd:YAG laser. The corresponding microstructure, phase structure, microhardness profiles, corrosion properties and bioactivity of the laser-alloyed coatings are investigated to optimize the atomic ratio of Ti–Si. The laser alloyed Ti–Si compound coatings are free of cracks, and primarily present block-like crystals, lath-like crystals and dendrite crystals. The phase structures of both laser-alloyed Ti + Si and 5Ti + 3Si coatings are mainly consisted of α-Ti and Ti{sub 5}Si{sub 3}, while the laser-alloyed Si coating is mainly consisted of TiSi{sub 2} and Ti{sub 5}Si{sub 3}. Microhardness test indicates that the laser-alloyed Si coating has the highest microhardness. Also, corrosion resistance measurement reveals that the corrosion resistance of the laser-alloyed Si coating is much better than that of the Ti–6Al–4V alloy. Evaluation of bioactivity shows that cell growth on the laser-alloyed Si coating with high volume fraction of Ti–Si compounds is faster than that of the Ti–6Al–4V alloy.

  7. Zirconium modified nickel-copper alloy

    Whittenberger, J. D. (Inventor)


    An improved material for use in a catalytic reactor which reduces nitrogen oxide from internal combustion engines is in the form of a zirconium-modified, precipitation-strengthened nickel-copper alloy. This material has a nominal composition of Ni-30 Cu-0.2 Zr and is characterized by improved high temperature mechanical properties.

  8. Laser polishing of additive manufactured Ti alloys

    Ma, C. P.; Guan, Y. C.; Zhou, W.


    Laser-based additive manufacturing has attracted much attention as a promising 3D printing method for metallic components in recent years. However, surface roughness of additive manufactured components has been considered as a challenge to achieve high performance. In this work, we demonstrate the capability of fiber laser in polishing rough surface of additive manufactured Ti-based alloys as Ti-6Al-4V and TC11. Both as-received surface and laser-polished surfaces as well as cross-section subsurfaces were analyzed carefully by White-Light Interference, Confocal Microscope, Focus Ion Beam, Scanning Electron Microscopy, Energy Dispersive Spectrometer, and X-ray Diffraction. Results revealed that as-received Ti-based alloys with surface roughness more than 5 μm could be reduce to less than 1 μm through laser polishing process. Moreover, microstructure, microhardness and wear resistance of laser-polished zone was investigated in order to examine the thermal effect of laser polishing processing on the substrate of additive manufactured Ti alloys. This proof-of-concept process has the potential to effectively improve the surface roughness of additive manufactured metallic alloy by local polishing method without damage to the substrate.

  9. Materials data handbook on Inconel Alloy 718

    Muraca, R. F.; Whittick, J. S.


    Handbook is divided into twelve chapters. Scope of information presented includes physical- and mechanical-property data at cryogenic, ambient, and elevated temperatures. This is supplemented with useful information in such areas as material procurement, metallurgy of alloy, corrosion, environmental effect, fabrication, and joining techniques. Design data are presented, as available.

  10. Amorphous Alloy and Magnetic Stabilization Bed


    @@ Sponsored by NSFC,a research team led by Prof.Enze Min (CAS Member) from Research Institute of Petroleum Processing,through 20 years' effort,settled the puzzled grave issue that amorphous alloy material has small specific surface area and low thermal stability.

  11. Mechanocaloric effects in shape memory alloys.

    Mañosa, Lluís; Planes, Antoni


    Shape memory alloys (SMA) are a class of ferroic materials which undergo a structural (martensitic) transition where the associated ferroic property is a lattice distortion (strain). The sensitiveness of the transition to the conjugated external field (stress), together with the latent heat of the transition, gives rise to giant mechanocaloric effects. In non-magnetic SMA, the lattice distortion is mostly described by a pure shear and the martensitic transition in this family of alloys is strongly affected by uniaxial stress, whereas it is basically insensitive to hydrostatic pressure. As a result, non-magnetic alloys exhibit giant elastocaloric effects but negligible barocaloric effects. By contrast, in a number of magnetic SMA, the lattice distortion at the martensitic transition involves a volume change in addition to the shear strain. Those alloys are affected by both uniaxial stress and hydrostatic pressure and they exhibit giant elastocaloric and barocaloric effects. The paper aims at providing a critical survey of available experimental data on elastocaloric and barocaloric effects in magnetic and non-magnetic SMA.This article is part of the themed issue 'Taking the temperature of phase transitions in cool materials'.

  12. R-HPDC of magnesium alloys

    Curle, UA


    Full Text Available different magnesium alloys (AM50A, AM60B, AZ91D) in a first attempt. All as-cast microstructures are characterised more by rosette shaped globules of the primary-(Mg) phase together with Mg(sub17)Al(sub12) as evidence of nonequilibrium cooling rates. Surface...

  13. Evolution of morphology in solidifying aluminium alloys

    Dijkstra, W.O.


    In the thesis two different models of solidification of aluminum alloys are presented and analyzed. The first 1--D solidification model is derived from the conservation of solute, heat and mass. With numerical experiments it is shown that simulations with the Finite Difference discretization must

  14. Nickel-titanium alloys: a systematic review

    Marcelo do Amaral Ferreira


    Full Text Available OBJECTIVE: A systematic review on nickel-titanium wires was performed. The strategy was focused on Entrez-PubMed-OLDMEDLINE, Scopus and BioMed Central from 1963 to 2008. METHODS: Papers in English and French describing the behavior of these wires and laboratorial methods to identify crystalline transformation were considered. A total of 29 papers were selected. RESULTS: Nickel-titanium wires show exceptional features in terms of elasticity and shape memory effects. However, clinical applications request a deeper knowledge of these properties in order to allow the professional to use them in a rational manner. In addition, the necessary information regarding each alloy often does not correspond to the information given by the manufacturer. Many alloys called "superelastic" do not present this effect; they just behave as less stiff alloys, with a larger springback if compared to the stainless steel wires. CONCLUSIONS: Laboratory tests are the only means to observe the real behavior of these materials, including temperature transition range (TTR and applied tensions. However, it is also possible to determine in which TTR these alloys change the crystalline structure.

  15. Atomic displacements in bcc dilute alloys

    Hitesh Sharma; S Prakash


    We present here a systematic investigation of the atomic displacements in bcc transition metal (TM) dilute alloys. We have calculated the atomic displacements in bcc (V, Cr, Fe, Nb, Mo, Ta and W) transition metals (TMs) due to 3d, 4d and 5d TMs at the substitutional site using the Kanzaki lattice static method. Wills and Harrison interatomic potential is used to calculate the atomic force constants, the dynamical matrix and the impurity-induced forces. We have thoroughly investigated the atomic displacements using impurities from 3d, 4d and 5d series in the same host metal and the same impurity in different hosts. We have observed a systematic pattern in the atomic displacements for Cr-, Fe-, Nb-, Mo-, Ta- and W-based dilute alloys. The atomic displacements are found to increase with increase in the number of d electrons for all alloys considered except for V dilute alloys. The 3d impurities are found to be more easily dissolved in the 3d host metals than 4d or 5d TMs whereas 4d and 5d impurities show more solubility in 4d and 5d TMs. In general, the relaxation energy calculation suggests that impurities may be easily solvable in 5d TM hosts when compared to 3d or 4d TMs.

  16. High-strength iron aluminide alloys

    McKamey, C.G.; Marrero-Santos, Y.; Maziasz, P.J.


    Past studies have shown that binary Fe{sub 3}Al possesses low creep-rupture strength compared to many other alloys, with creep-rupture lives of less than 5 h being reported for tests conducted at 593{degrees}C and 207 MPa. The combination of poor creep resistance and low room-temperature tensile density due to a susceptibility to environmentally-induced dynamic hydrogen embrittlement has limited use of these alloys for structural applications, despite their excellent corrosion properties. Improvements in room temperature tensile ductility have been realized mainly through alloying effects, changes in thermomechanical processing to control microstructure, and by control of the specimen`s surface condition. Ductilities of 10-20% and tensile yield strengths as high as 500 MPa have been reported. In terms of creep-rupture strength, small additions of Mo, Nb, and Zr have produced significant improvements, but at the expense of weldability and room-temperature tensile ductility. Recently an alloy containing these additions, designated FA-180, was shown to exhibit a creep-rupture life of over 2000 h after a heat treatment of 1 h at 1150{degrees}C. This study presents the results of creep-rupture tests at various test temperatures and stresses and discusses the results as part of our effort to understand the strengthening mechanisms involved with heat treatment at 1150{degrees}C.

  17. Antiferromagnetism in chromium alloy single crystals

    Bjerrum Møller, Hans; Trego, A.L.; Mackintosh, A.R.


    The antiferromagnetism of single crystals of dilute alloys of V, Mn and Re in Cr has been studied at 95°K and 300°K by neutron diffraction. The addition of V causes the diffraction peaks to decrease in intensity and move away from (100), while Mn and Re cause them to increase and approach (100) so...

  18. Reduction in Defect Content of ODS Alloys

    Ritherdon, J


    The work detailed within this report is a continuation of earlier work carried out under contract number 1DX-SY382V. The earlier work comprises a literature review of the sources and types of defects found principally in Fe-based ODS alloys as well as experimental work designed to identify defects in the prototype ODS-Fe{sub 3}Al alloy, deduce their origins and to recommend methods of defect reduction. The present work is an extension of the experimental work already reported and concentrates on means of reduction of defects already identified rather than the search for new defect types. This report also includes results gathered during powder separation trials, conducted by the University of Groningen, Netherlands and coordinated by the University of Liverpool, involving the separation of different metallic powders in terms of their differing densities. The scope and objectives of the present work were laid out in the technical proposal ''Reduction in Defect Content in ODS Alloys-III''. All the work proposed in the ''Statement of Work'' section of the technical proposal has been carried out and all work extra to the ''Statement of Work'' falls within the context of an ODS-Fe{sub 3}Al alloy of improved overall quality and potential creep performance in the consolidated form. The outturn of the experimental work performed is reported in the following sections.

  19. Shape-Memory-Alloy Release Mechanism

    Mckinnis, Darin


    Release-nut mechanism activated by electric current applied to shape-memory alloy. Separates attached objects quickly by remote control. Does not create hazard or cause damage. Shape-memory release-nut mechanism unaffected by moisture or vacuum. Requires sustained current lasting 5 seconds or longer, and insensitive to electromagnetic interference. Mechanism can be reused.

  20. Aluminized alloy boosts turbine blade life

    Gedwill, M. A.; Grisaffe, S. J.


    Description of an aluminized alloy coating technique that involves first the application of a ductile, oxidation-resistant overlay, such as NiCrAl, which is then partially aluminized. The duplex protective system has performance advantages over conventional aluminide coatings in that it provides higher-temperature hot corrosion resistance over a longer service life.