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Sample records for quasicrystalline al-based alloys

  1. Laser cladding of quasicrystalline alloys

    International Nuclear Information System (INIS)

    Audebert, F.; Sirkin, H.; Colaco, R.; Vilar, R.

    1998-01-01

    Quasicrystals are a new class of ordinated structures with metastable characteristics room temperature. Quasicrystalline phases can be obtained by rapid quenching from the melt of some alloys. In general, quasicrystals present properties which make these alloys promising for wear and corrosion resistant coatings applications. During the last years, the development of quasicrystalline coatings by means of thermal spray techniques has been impulsed. However, no references have been found of their application by means of laser techniques. In this work four claddings of quasicrystalline compositions formed over aluminium substrate, produced by a continuous CO 2 laser using simultaneous powders mixture injection are presented. The claddings were characterized by X ray diffraction, scanning electron microscopy and Vickers microhardness. (Author) 18 refs

  2. Formation of nano quasicrystalline and crystalline phases by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Shamah, A.M.; Ibrahim, S. [Faculty of Petroleum and Mining Engineering, Suez Canal University, Suez (Egypt); Hanna, F.F., E-mail: fariedhanna@yahoo.com [Faculty of Petroleum and Mining Engineering, Suez Canal University, Suez (Egypt)

    2011-02-03

    Research highlights: > Mechanical alloying (MA) is an important method to investigate the formation of nano sized quasicrystalline phases in Al{sub 86}Cr{sub 14}, Al{sub 84}Fe{sub 16} and Al{sub 62.5}Cu{sub 25}Fe{sub 12.5} compounds. The second part of the present work is an attempt to examine the possibility of formation of the i-phase of the Al{sub 62.5}Cu{sub 25}Fe{sub 12.5}, which lies in the region of the perfect i-phase in the ternary phase diagram, by rapid solidification method. To perform the obtained quasi phase mechanical alloying and heat treatment at the rapid solidified sample were done. - Abstract: In the present work, the formation of nano quasicrystalline icosahedral phase in Al{sub 86}Cr{sub 14}, Al{sub 84}Fe{sub 16} and Al{sub 62.5}Cu{sub 25}Fe{sub 12.5} alloys has been investigated by mechanical alloying. Mixtures of quasicrystalline and related crystalline phases have been observed under various milling conditions. The X-ray diffraction, differential thermal analysis and electrical resistivity techniques have been used for characterization and physical property measurements. The particle size was calculated by X-ray profile using Williamson-Hall plot method and it was found to be 25-50 nm size.

  3. Formation of nano quasicrystalline and crystalline phases by mechanical alloying

    International Nuclear Information System (INIS)

    Shamah, A.M.; Ibrahim, S.; Hanna, F.F.

    2011-01-01

    Research highlights: → Mechanical alloying (MA) is an important method to investigate the formation of nano sized quasicrystalline phases in Al 86 Cr 14 , Al 84 Fe 16 and Al 62.5 Cu 25 Fe 12.5 compounds. The second part of the present work is an attempt to examine the possibility of formation of the i-phase of the Al 62.5 Cu 25 Fe 12.5 , which lies in the region of the perfect i-phase in the ternary phase diagram, by rapid solidification method. To perform the obtained quasi phase mechanical alloying and heat treatment at the rapid solidified sample were done. - Abstract: In the present work, the formation of nano quasicrystalline icosahedral phase in Al 86 Cr 14 , Al 84 Fe 16 and Al 62.5 Cu 25 Fe 12.5 alloys has been investigated by mechanical alloying. Mixtures of quasicrystalline and related crystalline phases have been observed under various milling conditions. The X-ray diffraction, differential thermal analysis and electrical resistivity techniques have been used for characterization and physical property measurements. The particle size was calculated by X-ray profile using Williamson-Hall plot method and it was found to be 25-50 nm size.

  4. Structure and Mechanical Properties of Powdered Quasicrystalline Al94Fe3Cr3 Alloy Consolidated by Quasi-Hydrostatic Compression

    Directory of Open Access Journals (Sweden)

    Alexandra I. Yurkova

    2017-10-01

    Full Text Available Background. Quasicrystalline Al-based alloys belong to the class of the state-of-the-art metal materials for the application in light engineering constructions, primarily in aviation and the motor transport industry. These materials are commonly made in the form of powders, which is due to the high productivity of powder metallurgy methods. Therefore, the powder consolidation methods are of great importance in the production of products, which is associated with certain difficulties, and consequently, they should be chosen considering not only the quasicrystals’ propensity to brittle fracture but also the metastable nature of the quasicrystalline phases. Certain possibilities in this direction are provided by the quasi-hydrostatic compression method, which can provide a non-trivial combination of strength and ductility properties of materials. Objective. The aim of the paper is to investigate the effect of high pressure under quasi-hydrostatic compression on the formation of structure, phase composition and mechanical properties of the quasicrystalline Al94Fe3Cr3 alloy. Methods. 40 μm Al94Fe3Cr3 alloy quasicrystalline powder was fabricated by water-atomisation technique. Consolidation of quasicrystalline powder was performed by quasi-hydrostatic compression technique in high-pressure cells at room temperature at a pressure of 2.5, 4, and 6 hPa. Structure, phase composition and mechanical characteristics of Al94Fe3Cr3 alloy were performed by scanning electron microscopy (SEM, X-ray diffraction andmicromechanical tests. Results. Using the phase X-ray analysis and SEM, the content of the quasicrystalline icosahedral phase (i-phase in the Al94Fe3Cr3 alloy structure was completely preserved after its consolidation at different pressures (2.5, 4, and 6 hPa under quasi-hydrostatic compression at room temperature. Despite the high pressure applied in the consolidation process, the morphology of quasicrystalline phase particles located in the a

  5. Decagonal quasicrystalline phase in as-cast and mechanically alloyed Al–Cu–Cr alloys

    International Nuclear Information System (INIS)

    Shevchukov, A.P.; Sviridova, T.A.; Kaloshkin, S.D.; Tcherdyntsev, V.V.; Gorshenkov, M.V.; Churyukanova, M.N.; Zhang, D.; Li, Z.

    2014-01-01

    Highlights: ► Microstructure of as-cast Al–Cu–Cr alloys was investigated. ► Composition of decagonal quasicrystalline phase was determined. ► Single-phase decagonal quasicrystalline powder was obtained. ► Phase composition changes during heating were controlled using DSC and X-ray diffraction. -- Abstract: Microstructure and phase composition of three Al-rich as-cast alloys of Al–Cu–Cr system were investigated by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). The decagonal quasicrystalline phase is contained in all alloys under study and has grains with faceted shape, its composition lies in the range of 71–73 at.% Al, 11–12 at.% Cu and 15–18 at.% Cr. The heating in calorimeter of the mechanically alloyed Al 73 Cu 11 Cr 16 powder up to 600 °C leads to the formation of the pure decagonal phase. Total thermal effect in the temperature range 250–600 °C corresponding to the quasicrystalline phase formation is about 15 kJ/mol

  6. Alloy with metallic glass and quasi-crystalline properties

    Science.gov (United States)

    Xing, Li-Qian; Hufnagel, Todd C.; Ramesh, Kaliat T.

    2004-02-17

    An alloy is described that is capable of forming a metallic glass at moderate cooling rates and exhibits large plastic flow at ambient temperature. Preferably, the alloy has a composition of (Zr, Hf).sub.a Ta.sub.b Ti.sub.c Cu.sub.d Ni.sub.e Al.sub.f, where the composition ranges (in atomic percent) are 45.ltoreq.a.ltoreq.70, 3.ltoreq.b.ltoreq.7.5, 0.ltoreq.c.ltoreq.4, 3.ltoreq.b+c.ltoreq.10, 10.ltoreq.d.ltoreq.30, 0.ltoreq.e.ltoreq.20, 10.ltoreq.d+e.ltoreq.35, and 5.ltoreq.f.ltoreq.15. The alloy may be cast into a bulk solid with disordered atomic-scale structure, i.e., a metallic glass, by a variety of techniques including copper mold die casting and planar flow casting. The as-cast amorphous solid has good ductility while retaining all of the characteristic features of known metallic glasses, including a distinct glass transition, a supercooled liquid region, and an absence of long-range atomic order. The alloy may be used to form a composite structure including quasi-crystals embedded in an amorphous matrix. Such a composite quasi-crystalline structure has much higher mechanical strength than a crystalline structure.

  7. Characteristics of mechanical alloying of Zn-Al-based alloys

    International Nuclear Information System (INIS)

    Zhu, Y.H.; Hong Kong Polytechnic; Perez Hernandez, A.; Lee, W.B.

    2001-01-01

    Three pure elemental powder mixtures of Zn-22%Al-18%Cu, Zn-5%Al-11%Cu, and Zn-27%Al-3%Cu (in wt.%) were mechanically alloyed by steel-ball milling processing. The mechanical alloying characteristics were investigated using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy techniques. It was explored that mechanical alloying started with the formation of phases from pure elemental powders, and this was followed by mechanical milling-induced phase transformation. During mechanical alloying, phases stable at the higher temperatures formed at the near room temperature of milling. Nano-structure Zn-Al-based alloys were produced by mechanical alloying. (orig.)

  8. Effects in Mg-Zn-based alloys strengthened by quasicrystalline phase

    International Nuclear Information System (INIS)

    Vlček, M; Čížek, J; Lukáč, F; Melikhova, O; Hruška, P; Procházka, I; Vlach, M; Stulíková, I; Smola, B; Jäger, A

    2016-01-01

    Magnesium Mg-based alloys are promising lightweight structural materials for automotive, aerospace and biomedical applications. Recently Mg-Zn-Y system attracted a great attention due to a stable icosahedral phase (I-phase) with quasicrystalline structure which is formed in these alloys. Positron lifetime spectroscopy and in situ synchrotron X-ray diffraction were used to study thermal stability of I-phase and precipitation effects in Mg-Zn-Y and Mg- Zn-Al alloys. All alloys containing quasicrystalline I-phase exhibit misfit defects characterized by positron lifetime of ∼ 300 ps. These defects are associated with the interfaces between I- phase particles and Mg matrix. The quasicrystalline I-phase particles were found to be stable up to temperatures as high as ∼ 370°C. The W-phase is more stable and melts at ∼ 420°C. Concentration of defects associated with I-phase decreases after annealing at temperatures above ∼ 300°C. (paper)

  9. The quasicrystalline phase formation in Al-Cu-Cr alloys produced by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Sviridova, T.A.; Shevchukov, A.P.; Shelekhov, E.V. [National University of Science and Technology ' MISIS' , Moscow 119049 (Russian Federation); Diakonov, D.L. [Bardin Central Research Institute for the Iron and Steel Industry, Moscow 105005 (Russian Federation); Tcherdyntsev, V.V.; Kaloshkin, S.D. [National University of Science and Technology ' MISIS' , Moscow 119049 (Russian Federation)

    2011-06-15

    Research highlights: > Formation of decagonal quasicrystalline phase in Al-Cu-Cr alloys. > Obtained decagonal phase belongs to D{sub 3} family of decagonal quasicrystals. > Decagonal phase has 1.26 nm periodicity along 10-fold axis. > Alloys were produced by combination of mechanical alloying and subsequent annealing. > Phase composition of as-milled powders depending on annealing temperature. - Abstract: Almost single-phase decagonal quasicrystal with periodicity of 1.26 nm along 10-fold axis was produced in Al{sub 69}Cu{sub 21}Cr{sub 10} and Al{sub 72.5}Cu{sub 16.5}Cr{sub 11} alloys using combination of mechanical alloying (MA) and subsequent annealing. Phase transformations of as-milled powders depending on annealing temperature in the range of 200-800 deg. C are examined. Since the transformations can be explained based on kinetic and thermodynamic reasons it seems that applied technique (short preliminary MA followed by the annealing) permits to produce the equilibrium phases rather than metastable ones.

  10. Room temperature deformation of in-situ grown quasicrystals embedded in Al-based cast alloy

    Directory of Open Access Journals (Sweden)

    Boštjan Markoli

    2013-12-01

    Full Text Available An Al-based cast alloy containing Mn, Be and Cu has been chosen to investigate the room temperature deformation behavior of QC particles embedded in Al-matrix. Using LOM, SEM (equipped with EDS, conventional TEM with SAED and controlled tensile and compression tests, the deformation response of AlMn2Be2Cu2 cast alloy at room temperature has been examined. Alloy consisted of Al-based matrix, primary particles and eutectic icosahedral quasicrystalline (QC i-phase and traces of Θ-Al2Cu and Al10Mn3. Tensile and compression specimens were used for evaluation of mechanical response and behavior of QC i-phase articles embedded in Al-cast alloy. It has been established that embedded QC i-phase particles undergo plastic deformation along with the Al-based matrix even under severe deformation and have the response resembling that of the metallic materials by formation of typical cup-and-cone feature prior to failure. So, we can conclude that QC i-phase has the ability to undergo plastic deformation along with the Al-matrix to greater extent contrary to e.g. intermetallics such as Θ-Al2Cu for instance.

  11. Al-based metal matrix composites reinforced with Al–Cu–Fe quasicrystalline particles: Strengthening by interfacial reaction

    International Nuclear Information System (INIS)

    Ali, F.; Scudino, S.; Anwar, M.S.; Shahid, R.N.; Srivastava, V.C.; Uhlenwinkel, V.; Stoica, M.; Vaughan, G.; Eckert, J.

    2014-01-01

    Highlights: • Strength of composites is enhanced as the QC-to-ω phase transformation advances. • Yield strength increases from 195 to 400 MPa with QC-to-ω interfacial reaction. • Reducing matrix ligament size explains most of the strengthening. • Improved interfacial bonding and nano ω phase explains divergence from model. - Abstract: The interfacial reaction between the Al matrix and the Al 62.5 Cu 25 Fe 12.5 quasicrystalline (QC) reinforcing particles to form the Al 7 Cu 2 Fe ω-phase has been used to further enhance the strength of the Al/QC composites. The QC-to-ω phase transformation during heating was studied by in situ X-ray diffraction using a high-energy monochromatic synchrotron beam, which permits to follow the structural evolution and to correlate it with the mechanical properties of the composites. The mechanical behavior of these transformation-strengthened composites is remarkably improved as the QC-to-ω phase transformation progresses: the yield strength increases from 195 MPa for the starting material reinforced exclusively with QC particles to 400 MPa for the material where the QC-to-ω reaction is complete. The reduction of the matrix ligament size resulting from the increased volume fraction of the reinforcing phase during the transformation can account for most of the observed improvement in strength, whereas the additional strengthening can be ascribed to the possible presence of nanosized ω-phase particles as well as to the improved interfacial bonding between matrix and particles caused by the compressive stresses arising in the matrix

  12. Al-based metal matrix composites reinforced with Al–Cu–Fe quasicrystalline particles: Strengthening by interfacial reaction

    Energy Technology Data Exchange (ETDEWEB)

    Ali, F. [IFW Dresden, Institut für Komplexe Materialien, Postfach 27 01 16, D-01171 Dresden (Germany); Materials Processing Group, DMME, Pakistan Institute of Engineering and Applied Sciences, P.O. Nilore, Islamabad (Pakistan); Scudino, S., E-mail: s.scudino@ifw-dresden.de [IFW Dresden, Institut für Komplexe Materialien, Postfach 27 01 16, D-01171 Dresden (Germany); Anwar, M.S.; Shahid, R.N. [Materials Processing Group, DMME, Pakistan Institute of Engineering and Applied Sciences, P.O. Nilore, Islamabad (Pakistan); Srivastava, V.C. [Metal Extraction and Forming Division, National Metallurgical Laboratory, Jamshedpur 831007 (India); Uhlenwinkel, V. [Institut für Werkstofftechnik, Universität Bremen, D-28359 Bremen (Germany); Stoica, M. [IFW Dresden, Institut für Komplexe Materialien, Postfach 27 01 16, D-01171 Dresden (Germany); Vaughan, G. [European Synchrotron Radiation Facilities ESRF, BP 220, 38043 Grenoble (France); Eckert, J. [IFW Dresden, Institut für Komplexe Materialien, Postfach 27 01 16, D-01171 Dresden (Germany); TU Dresden, Institut für Werkstoffwissenschaft, D-01062 Dresden (Germany)

    2014-09-01

    Highlights: • Strength of composites is enhanced as the QC-to-ω phase transformation advances. • Yield strength increases from 195 to 400 MPa with QC-to-ω interfacial reaction. • Reducing matrix ligament size explains most of the strengthening. • Improved interfacial bonding and nano ω phase explains divergence from model. - Abstract: The interfacial reaction between the Al matrix and the Al{sub 62.5}Cu{sub 25}Fe{sub 12.5} quasicrystalline (QC) reinforcing particles to form the Al{sub 7}Cu{sub 2}Fe ω-phase has been used to further enhance the strength of the Al/QC composites. The QC-to-ω phase transformation during heating was studied by in situ X-ray diffraction using a high-energy monochromatic synchrotron beam, which permits to follow the structural evolution and to correlate it with the mechanical properties of the composites. The mechanical behavior of these transformation-strengthened composites is remarkably improved as the QC-to-ω phase transformation progresses: the yield strength increases from 195 MPa for the starting material reinforced exclusively with QC particles to 400 MPa for the material where the QC-to-ω reaction is complete. The reduction of the matrix ligament size resulting from the increased volume fraction of the reinforcing phase during the transformation can account for most of the observed improvement in strength, whereas the additional strengthening can be ascribed to the possible presence of nanosized ω-phase particles as well as to the improved interfacial bonding between matrix and particles caused by the compressive stresses arising in the matrix.

  13. Microstructure development and properties of the AlCuFe quasicrystalline coating on near-{alpha} titanium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Moskalewicz, T., E-mail: tmoskale@agh.edu.pl [Faculty of Metals Engineering and Industrial Computer Science, AGH University of Science and Technology, PL-30-059 Krakow, Al. A. Mickiewicza 30 (Poland); Kot, M. [Faculty of Mechanical Engineering and Robotics, AGH University of Science and Technology, PL-30-059 Krakow, Al. A. Mickiewicza 30 (Poland); Wendler, B. [Faculty of Mechanical Engineering, Technical University of Lodz, PL-90 924 Lodz, ul. Stefanowskiego 1 (Poland)

    2011-11-01

    A protective quasicrystalline AlFeCu coating was deposited on TIMETAL 834 substrate by nonreactive magnetron sputtering in order to improve resistance of the alloy to oxidation. Microstructure characterisation of the substrate and the coating was performed by analytical scanning- and transmission electron microscopy as well as X-ray diffractometry. Depending on annealing temperature and time, the deposited coating (2.7 {mu}m thick) has a different microstructure. The coating in Specimen 1 (annealed 600 deg. C/4 h in vacuum) consisted of two zones: outer, composed of Al{sub 5}Fe{sub 2} and Al{sub 2}Cu{sub 3} phases and inner, in which only quasicrystalline {psi} phase was present. The coating in Specimen 2 (annealed 600 deg. C/4 h + 700 deg. C/2 h in vacuum) was fully quasicrystalline and consisted of icosahedral {psi} phase. Both coatings exhibit higher microhardness than the substrate material. It was established that the applied surface treatment essentially improves oxidation resistance of the alloy tested at 750 deg. C during 250 h in static air. Sample weight gain was 60% lower than in the case of uncoated sample. Oxide scale spallation occurred for uncoated alloy while the coated one did not show any spallation. It was found that the very brittle scale formed during oxidation on the uncoated alloy was consisting of TiO{sub 2}, while that on the coated one consisted mainly of {alpha}-Al{sub 2}O{sub 3}.

  14. Quasicrystalline and crystalline phases in Al65Cu20(Fe, Cr)15 alloys

    International Nuclear Information System (INIS)

    Liu, W.; Koester, U.; Mueller, F.; Rosenberg, M.

    1992-01-01

    Two types of icosahedral quasicrystals are observed in Al 65 Cu 20 Fe 15-x Cr x (0 ≤ x ≤ 15) alloys, the face-centred AlCuFe-type icosahedral phase with dissoluted Cr and the primitive AlCuCr-type icosahedral phase with dissoluted Fe. In the vicinity of Al 65 Cu 20 Fe 8 Cr 7 a stable decagonal phase (a=0.45 nm and c=1.23 nm) forms competitively with the icosahedral quasicrystals. All these three quasicrystalline phases can be regarded as Hume-Rothery phases stabilized by the energy band factor. The density is measured to be 4.57, 4.44, and 4.11 g/cm 3 for the icosahedral Al 65 Cu 20 Fe 15 , the decagonal Al 65 Cu 20 Fe 8 Cr 7 , and the icosahedral Al 65 Cu 20 Cr 15 alloys, respectively. Depending on the composition in the range between Al 65 Cu 20 Fe 8 Cr 7 and Al 65 Cu 20 Cr 15 , several crystalline phases are observed during the transormation of the AlCuCr-type icosahedral phase: the 1/1-3/2-type orthorhombic (o) and the 1/0-3/2-type tetragonal (t) approximants of the decagonal phase, a hexagonal (h) phase, as well as a long-range vacancy ordered τ 3 -phase derived from a CsCl-type structure with a=0.2923 nm. The structures of all the crystalline phases are closely related to those of the icosahedral (i) and decagonal (d) quasicrystals, which leads to a definite orientation relationship as follows: i5 parallel d10 parallel o[100] parallel t[100] parallel h[001] parallel τ 3 [110]. (orig.)

  15. Melting and casting of FeAl-based cast alloy

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K. [Oak Ridge National Lab., TN (United States); Wilkening, D. [Columbia Falls Aluminum Co., Columbia Falls, MT (United States); Liebetrau, J.; Mackey, B. [AFFCO, L.L.C., Anaconda, MT (United States)

    1998-11-01

    The FeAl-based intermetallic alloys are of great interest because of their low density, low raw material cost, and excellent resistance to high-temperature oxidation, sulfidation, carburization, and molten salts. The applications based on these unique properties of FeAl require methods to melt and cast these alloys into complex-shaped castings and centrifugal cast tubes. This paper addresses the melting-related issues and the effect of chemistry on the microstructure and hardness of castings. It is concluded that the use of the Exo-Melt{trademark} process for melting and the proper selection of the aluminum melt stock can result in porosity-free castings. The FeAl alloys can be melted and cast from the virgin and revert stock. A large variation in carbon content of the alloys is possible before the precipitation of graphite flakes occurs. Titanium is a very potent addition to refine the grain size of castings. A range of complex sand castings and two different sizes of centrifugal cast tubes of the alloy have already been cast.

  16. Electron-beam-induced structure transformation of the quasicrystalline phases of the Al 62Cu 20Co 15Si 3 alloy

    Science.gov (United States)

    Reyes-Gasga, J.; R. Garcia, G.; Jose-Yacaman, M.

    1995-02-01

    Some details on the phase transformation experienced by the quasicrystalline phases of the Al 62Cu 20Co 15Si 3 alloy under a 400 kV electron beam are given. The transition is observed in situ with a high resolution electron microscope and recorded on video tape. The results show that the electron beam radiation produces a sequence of changes similar to the ones observed in an ion-beam-induced amorphization process. Considering electron radiation damage analysis, the results agree well with the "flip-flop" model [Coddens, Bellisent, Calvayrac and Ambroise (1991) Europhys. Lett.16, 271] where the transition from a quasicrystalline phase to a crystalline phase is produced by atomic displacements but not in a cascade way.

  17. Investigations of the Electronic Properties and Surface Structures of Aluminium-Rich Quasicrystalline Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Barrow, Jason A. [Iowa State Univ., Ames, IA (United States)

    2003-01-01

    equations. Transport behavior is described in terms of charge carriers and the mean-free time between carrier collisions. It is concluded that the mean-free time is much longer in the periodic direction than in the aperiodic direction. This difference produces the observed anisotropy in thermal transport. The third study presented a detailed analysis of the reversible, sputter-induced phase transformation which occurs on the 5-fold surface of an icosahedral Al-Cu-Fe quasicrystal. Reflection high-energy electron diffraction (RHEED), x-ray photoemission spectroscopy (XPS), and ultra-violet photoemission spectroscopy (UPS) data were collected as a function of annealing temperature and were used to probe surface structure, surface composition, and electronic structure, respectively. The composition and structure of the sputtered surface are consistent with a transformation to the β-Al-Cu-Fe cubic structure, and shows a sharp metallic cut-off in the spectral intensity of the electronic structure at the Fermi edge. Upon annealing the surface reverts to a quasicrystalline composition and structure. This transformation has been correlated with a reduction in the spectral intensity of the electronic structure at the Fermi level. This data clearly demonstrates that the observed reduction is intrinsic to a quasicrystalline surface. It is concluded that this is due to the opening of a pseudo-gap in the electronic density of states as the surface reverts from β-Al-Cu-Fe to quasicrystalline.

  18. Ductile-phase toughening and fatigue crack growth in Nb3Al base alloys

    International Nuclear Information System (INIS)

    Gnanamoorthy, R.; Hanada, S.

    1996-01-01

    Niobium aluminide (Nb 3 Al) base intermetallic compounds exhibit good high-temperature strength and creep properties and potential for applications above 1,200 C provided their inadequately low room-temperature ductility, fracture toughness and fatigue crack growth behavior are improved. Addition of tantalum to Nb 3 Al base materials improves the high-temperature strength significantly and seems to be a potential alloying element. In the present study, room temperature fracture toughness and fatigue crack growth behavior of tantalum alloyed Nb 3 Al base alloy prepared by ingot metallurgy are investigated

  19. Excessively High Vapor Pressure of Al-based Amorphous Alloys

    Directory of Open Access Journals (Sweden)

    Jae Im Jeong

    2015-10-01

    Full Text Available Aluminum-based amorphous alloys exhibited an abnormally high vapor pressure at their approximate glass transition temperatures. The vapor pressure was confirmed by the formation of Al nanocrystallites from condensation, which was attributed to weight loss of the amorphous alloys. The amount of weight loss varied with the amorphous alloy compositions and was inversely proportional to their glass-forming ability. The vapor pressure of the amorphous alloys around 573 K was close to the vapor pressure of crystalline Al near its melting temperature, 873 K. Our results strongly suggest the possibility of fabricating nanocrystallites or thin films by evaporation at low temperatures.

  20. The corrosion behaviour of Zr3Al-based alloys

    International Nuclear Information System (INIS)

    Murphy, E.V.; Wieler, R.

    1977-07-01

    The corrosion resistance of several zirconium-aluminum alloys with aluminum contents ranging from 7.6 to 9.6 wt% was examined in 300 deg C and 325 deg C water, 350 deg C and 400 deg C steam and in air and wet CO 2 at 325 deg C and 400 deg C. In the transformed alloys there are three phases present, αZr, Zr 2 Al and Zr 3 Al of which the αZr phase is the least corrosion resistant. The most important factor controlling the corrosion behaviour of these alloys was found to be the size, distribution and amount of the αZr phase in the transformed alloys, which in turn was dependent upon the microstructural scale of the untransformed alloys

  1. Measurement of the thermoelectric properties of quasicrystalline AlPdRe and AlCuFe alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, M L; LeGault, S; Stroud, R M; Tritt, T M

    1997-07-01

    The authors report the measurement of the thermal conductivity, electrical resistivity, and thermoelectric power on two quasicrystalline compounds, Al{sub 70}Pd{sub 20}Re{sub 10} and Al{sub 62.5}Cu{sub 25}Fe{sub 12.5}. These materials are found to possess a thermal conductivity of order 1 W/m{center{underscore}dot}K, while retaining their semimetallic conductivity. These features coupled with moderately large thermopowers, up to 55 {micro}V/K, imply that the general class of quasicrystalline compounds warrants careful investigation for their potential as new thermoelectric materials.

  2. Fatigue properties and microstructure of quasicrystalline AlFeCrTi alloy

    Czech Academy of Sciences Publication Activity Database

    Chlupová, Alice; Chlup, Zdeněk; Kruml, Tomáš

    2016-01-01

    Roč. 91, OCT (2016), s. 251-256 ISSN 0142-1123 R&D Projects: GA MŠk(CZ) LQ1601 Institutional support: RVO:68081723 Keywords : Aluminium alloy * Quasicrystals * Fatigue * Fractography Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.899, year: 2016

  3. Oxidation Behavior of TiAl-Based Alloy Modified by Double-Glow Plasma Surface Alloying with Cr-Mo

    Science.gov (United States)

    Wei, Xiangfei; Zhang, Pingze; Wang, Qiong; Wei, Dongbo; Chen, Xiaohu

    2017-07-01

    A Cr-Mo alloyed layer was prepared on a TiAl-based alloy using plasma surface alloying technique. The isothermal oxidation kinetics of the untreated and treated samples was examined at 850 °C. The microstructure and phase composition of the alloyed layer were analyzed by scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and X-ray powder diffraction (XRD). The morphology and constituent of the oxide scales were also analyzed. The results indicated that the oxidation resistance of TiAl was improved significantly after the alloying treatment. The oxide scale eventually became a mixture of Al2O3, Cr2O3 and TiO2. The oxide scale was dense and integrated throughout the oxidation process. The improvement was mainly owing to the enhancing of scale adhesion and the preferential oxidation of aluminum brought by the alloying effect for TiAl-based alloy.

  4. Design and fabrication of a mechanical alloying system for preparing intermetallic, nanocrystalline, amorphous and quasicrystalline compounds

    International Nuclear Information System (INIS)

    Bonifacio M, J.; Iturbe G, J.L.; Castaneda J, G.

    2002-01-01

    In this work a grinding system was designed and fabricated which allowed to improve the operation conditions in time, frequency, temperature and selection of the grinding media and that allow the contamination decrease of the compounds. By means of this method of mechanical alloying new metallic compounds can be produced, starting from elemental powders, with fine and controlled microstructures. These compounds prepared by this method are going to be used as materials for the hydrogen storage. (Author)

  5. Driving forces of redistribution of elements during quasicrystalline phase formation under heating of mechanically alloyed Al65Cu23Fe12 powder

    Science.gov (United States)

    Tcherdyntsev, V. V.; Kaloshkin, S. D.; Shelekhov, E. V.; Principi, G.; Rodin, A. O.

    2008-02-01

    Al65Cu23Fe12 alloys were prepared by ball milling of the elemental powders mixture. Phase and structural transformations at heating of as-milled powders were investigated by X-ray diffraction analysis. Precision analysis of Mössbauer spectra was performed to check the adequacy of the fitting of X-ray diffraction patterns. The results were compared with the data of differential scanning and solution calorimetry, as well as with the thermodynamic literature data, in order to estimate the driving forces of redistribution of elements that preceded the formation of single-phase quasicrystalline structure. The heat of elements mixing, which is positive for Cu-Fe system and negative for Al-Fe and Al-Cu systems, was supposed to be a decisive factor for phase transformations during heating of the alloy. The correlation between sequence of phase transformations during heating and the thermodynamic data was discussed and the scheme describing phase transformations observed was proposed.

  6. Phase transformations in TiAl based alloys

    International Nuclear Information System (INIS)

    Zghal, Slim; Thomas, Marc; Naka, Shigehisa; Finel, Alphonse; Couret, Alain

    2005-01-01

    Microstructural characteristics of a fully lamellar Ti 49 Al 47 Cr 2 Nb 2 alloy have been investigated in different annealed conditions by quantitative transmission electron microscopy. Statistical analyses have yielded clear information about the γ-γ interfaces, the respective orientation groups of the γ phase, and the distribution of orientational variants. From the results, three sequences of lamellar transformation have been identified with decreasing temperature: (1) a high-temperature heterogeneous transformation characterized by the nucleation of isolated primary γ lamellae mostly belonging to the same orientation group and having locally the same order; (2) a low-temperature homogeneous transformation in the ordered α 2 phase characterized by the formation of a fine lamellar structure with an even distribution of the orientation groups and a random ordering of γ lamellae; and (3) a coherent interfacial transformation at the α 2 /γ interfaces characterized by the nucleation of ultra-fine twin related lamellae. Finally, the driving forces for these various transformations as well as the nucleation mechanisms of γ lamellae involved in these transformations are discussed

  7. Nanocrystalline Al-based alloys - lightweight materials with attractive mechanical properties

    International Nuclear Information System (INIS)

    Latuch, J; Cieslak, G; Dimitrov, H; Krasnowski, M; Kulik, T

    2009-01-01

    In this study, several ways of bulk nanocrystalline Al-based alloys' production by high-pressure compaction of powders were explored. The effect of chemical composition and compaction parameters on the structure, quality and mechanical properties of the bulk samples was studied. Bulk nanocrystalline Al-Mm-Ni-(Fe,Co) alloys were prepared by ball-milling of amorphous ribbons followed by consolidation. The maximum microhardness (540 HV0.1) was achieved for the samples compacted at 275 deg. C under 7.7 GPa (which resulted in an amorphous bulk) and nanocrystallised at 235 deg. C for 20 min. Another group of the produced materials were bulk nanocrystalline Al-Si-(Ni,Fe)-Mm alloys obtained by ball-milling of nanocrystalline ribbons and consolidation. The hardness of these samples achieved the value five times higher (350HV) than that of commercial 4xxx series Al alloys. Nanocrystalline Al-based alloys were also prepared by mechanical alloying followed by hot-pressing. In this group of materials, there were Al-Fe alloys containing 50-85 at.% of Al and ternary or quaternary Al-Fe-(Ti, Si, Ni, Mg, B) alloys. Microhardness of these alloys was in the range of 613 - 1235 HV0.2, depending on the composition.

  8. Bulk synthesis by spray forming of Al–Cu–Fe and Al–Cu–Fe–Sn alloys containing a quasicrystalline phase

    International Nuclear Information System (INIS)

    Srivastava, V.C.; Huttunen-Saarivirta, E.; Cui, C.; Uhlenwinkel, V.; Schulz, A.; Mukhopadhyay, N.K.

    2014-01-01

    Highlights: • 40 kg Bulk material spray formed based on Al–Cu–Fe and Al–Cu–Fe + Sn. • Deposited Al–Cu–Fe alloy showed single phase bulk quasicrystals(QC). • DSC, XRD and microscopic analyses were done to ascertain the QC nature. • Sn does not help in single phase quasicrystal formation in the deposit. • The possible structural evolution mechanisms have been discussed in detail. - Abstract: In this study, Al–Cu–Fe alloys without and with the addition of Sn and containing a quasicrystalline phase were spray deposited. The spray-deposited bulk materials were characterized in terms of microstructure and hardness. The results showed that the Al 62.5 Cu 25 Fe 12.5 alloy contains the icosahedral quasicrystalline phase (i-phase) along with the minor λ-Al 13 Fe 4 phase, whereas the Al 62.5 Cu 25 Fe 12.5 + Sn alloy contains five phases: the major i-phase and the crystalline phases of Sn, θ-Al 2 Cu, λ-Al 13 Fe 4 and β-AlFe(Cu) phases. These results have been corroborated by X-ray diffraction (XRD), scanning and transmission electron microscopies (SEM and TEM) and differential scanning calorimetry (DSC). The hardness value of the Al–Cu–Fe alloy reached 10.5 GPa at 50 g load and then decreased steadily with increase in the applied load, while that for Al–Cu–Fe–Sn alloy it was originally somewhat lower, then decreased dramatically with slight increase in the applied load but stayed constant with further load increase. The hardness indentations in Al–Cu–Fe alloy introduced cracking in the material, whereas in the case of Al–Cu–Fe–Sn alloy the Sn-rich areas inhibited the crack growth. The present study provides an insight into the mechanism of phase and microstructural evolutions during spray forming of the studied alloys. Furthermore, the role of Sn in terms of microstructure and properties is highlighted

  9. Intragranular nucleation sites of massive gamma grains in a TiAl-based alloy

    DEFF Research Database (Denmark)

    Dey, Suhash Ranjan; Bouzy, E.; Hazotte, A.

    2007-01-01

    Massive gamma grains were generated in a TiAl-based alloy through ice-water quenching from the alpha domain. Apart from those located along alpha(2)/alpha(2) grain boundaries, a few massive gamma grains were detected inside the alpha(2) grains. Some of these intragranular grains were revealed...

  10. Microstructure evolution and texture development in thermomechanically processed Mg-Li-Al based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Vinod [Department of Materials Science and Engineering, IIT Kanpur (India); Govind [Vikram Sarabhai Space Center, Trivandrum (India); Shekhar, Rajiv; Balasubramaniam, R. [Department of Materials Science and Engineering, IIT Kanpur (India); Balani, Kantesh, E-mail: kbalani@iitk.ac.in [Department of Materials Science and Engineering, IIT Kanpur (India)

    2012-06-15

    Highlights: Black-Right-Pointing-Pointer Thermomechanical processing of novel LAT 971 and LATZ 9531 Mg-Al-Li based alloys. Black-Right-Pointing-Pointer Microstructural deviation from the equilibrium phase diagram. Black-Right-Pointing-Pointer Disparity in texture of these alloys after hot-rolling (recrystallization and grain growth). Black-Right-Pointing-Pointer Role of alloying and phase distribution in affecting the texture/interplaner spacing. - Abstract: In the present study, the influence of alloying and thermomechanical processing on the microstructure and texture evolution on the two Mg-Li-Al based alloys, namely Mg-9 wt% Li-7 wt% Al-1 wt% Sn (LAT971) and Mg-9 wt% Li-5 wt% Al-3 wt% Sn-1 wt% Zn (LATZ9531) has been elicited. Novel Mg-Li-Al based alloys were cast (induction melting under protective atmosphere) followed by hot rolling at {approx}573 K with a cumulative reduction of five. A contrary dual phase dendritic microstructure rich in {alpha}-Mg, instead of {beta}-Li phase predicted by equilibrium phase diagram of Mg-Li binary alloy was observed. Preferential presence of Mg-Li-Sn primary precipitates (size 4-10 {mu}m) within {alpha}-Mg phase and Mg-Li-Al secondary precipitates (<3 {mu}m) interspersed in {beta}-Li indicated their degree of dissolution during hot-rolling and homogenization in the dual phase matrix. Presence of Al, Sn and Zn alloying elements in the Mg-Li based alloy has resulted an unusual dual-phase microstructure, change in the lattice parameter, and intriguing texture evolution after hot-rolling of cast LAT 971 and LATZ9531 alloy. Strong texture was absent in the as-cast samples whereas texture development after hot-rolling revealed an increased activity of the non-basal (101{sup Macron }0) slip planes. The quantification of the grain average misorientation (less than 2 Degree-Sign ) using electron backscattered diffraction confirmed the presence of strain free grains in majority of the grains (fraction >0.75) after hot-rolling of Mg-Li-Al

  11. Multi-step wrought processing of TiAl-based alloys

    International Nuclear Information System (INIS)

    Fuchs, G.E.

    1997-04-01

    Wrought processing will likely be needed for fabrication of a variety of TiAl-based alloy structural components. Laboratory and development work has usually relied on one-step forging to produce test material. Attempts to scale-up TiAl-based alloy processing has indicated that multi-step wrought processing is necessary. The purpose of this study was to examine potential multi-step processing routes, such as two-step isothermal forging and extrusion + isothermal forging. The effects of processing (I/M versus P/M), intermediate recrystallization heat treatments and processing route on the tensile and creep properties of Ti-48Al-2Nb-2Cr alloys were examined. The results of the testing were then compared to samples from the same heats of materials processed by one-step routes. Finally, by evaluating the effect of processing on microstructure and properties, optimized and potentially lower cost processing routes could be identified

  12. Microstructure and mechanical properties of multiphase NiAl-based alloys

    Science.gov (United States)

    Pank, D. R.; Koss, D. A.; Nathal, M. V.

    1990-01-01

    The effect of the gamma-prime phase on the deformation behavior and fracture resistance of melt-spun ribbons and consolidated bulk specimens of a series of Nial-based alloys with Co and Hf additions has been examined. The morphology, location, and volume fraction of the gamma-prime phase are significant factors in enhancing the fracture resistance of the normally brittle NiAl-based alloys. In particular, the results indicate that a continuous-grain-boundary film of gamma-prime can impart limited room-temperature ductility regardless of whether B2 or L10 NiAl is present. Guidelines for microstructure control in multiphase NiAl-based alloys are also presented.

  13. Correlation Between Superheated Liquid Fragility And Onset Temperature Of Crystallization For Al-Based Amorphous Alloys

    Directory of Open Access Journals (Sweden)

    Guo J.

    2015-06-01

    Full Text Available Amorphous alloys or metallic glasses have attracted significant interest in the materials science and engineering communities due to their unique physical, mechanical, and chemical properties. The viscous flow of amorphous alloys exhibiting high strain rate sensitivity and homogeneous deformation is considered to be an important characteristic in thermoplastic forming processes performed within the supercooled liquid region because it allows superplastic-like deformation behavior. Here, the correlation between the superheated liquid fragility, and the onset temperature of crystallization for Al-based alloys, is investigated. The activation energy for viscous flow of the liquid is also investigated. There is a negative correlation between the parameter of superheated liquid fragility and the onset temperature of crystallization in the same Al-based alloy system. The activation energy decreases as the onset temperature of crystallization increases. This indicates that the stability of a superheated liquid can affect the thermal stability of the amorphous alloy. It also means that a liquid with a large superheated liquid fragility, when rapidly solidified, forms an amorphous alloy with a low thermal stability.

  14. Research into Oil-based Colloidal-Graphite Lubricants for Forging of Al-based Alloys

    International Nuclear Information System (INIS)

    Petrov, A.; Petrov, P.; Petrov, M.

    2011-01-01

    The presented paper describes the topical problem in metal forging production. It deals with the choice of an optimal lubricant for forging of Al-based alloys. Within the scope of the paper, the properties of several oil-based colloidal-graphite lubricants were investigated. The physicochemical and technological properties of these lubricants are presented. It was found that physicochemical properties of lubricant compositions have an influence on friction coefficient value and quality of forgings.The ring compression method was used to estimate the friction coefficient value. Hydraulic press was used for the test. The comparative analysis of the investigated lubricants was carried out. The forging quality was estimated on the basis of production test. The practical recommendations were given to choose an optimal oil-based colloidal-graphite lubricant for isothermal forging of Al-based alloy.

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

    International Nuclear Information System (INIS)

    Zhang Zhengrong; Liu Wenxi

    2006-01-01

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

  16. Ultra-precision machining induced phase decomposition at surface of Zn-Al based alloy

    International Nuclear Information System (INIS)

    To, S.; Zhu, Y.H.; Lee, W.B.

    2006-01-01

    The microstructural changes and phase transformation of an ultra-precision machined Zn-Al based alloy were examined using X-ray diffraction and back-scattered electron microscopy techniques. Decomposition of the Zn-rich η phase and the related changes in crystal orientation was detected at the surface of the ultra-precision machined alloy specimen. The effects of the machining parameters, such as cutting speed and depth of cut, on the phase decomposition were discussed in comparison with the tensile and rolling induced microstrucutural changes and phase decomposition

  17. Chemical interaction of the In-Ga eutectic with Al and Al-base alloys

    International Nuclear Information System (INIS)

    Trenikhin, M.V.; Bubnov, A.V.; Duplyakin, V.K.; Nizovskij, A.I.

    2006-01-01

    The chemical interaction of the indium-gallium eutectic with Al and Al-base alloys is studied by X-ray diffraction, optical microscopy, and electron microscopy. Experimental data are presented that shed light on the reaction mechanism and the diffusion processes responsible for the subsequent disintegration of the material and its dissolution in water. Mechanical tests show that the activation of aluminum leads to a transition from plastic to brittle fracture [ru

  18. Study of the ternary alloy systems Al-Ni-Fe and Al-Cu-Ru with special regard to quasicrystalline phases

    International Nuclear Information System (INIS)

    Lemmerz, U.

    1996-07-01

    Two ternary alloy-systems, the Al-Ni-Fe system and the Al-Cu-Ru system were studied with special regard to quasicrystalline phases. Isothermal sections were established in both systems in the stoichiometric area of the quasicrystalline phase. In the Al-Ni-Fe system a new stable decagonal phase was found. Its stoichiometric range is very small around Al 71.6 Ni 23.0 Fe 5.4 . The temperature range in which it is stable lies between 847 and 930 C. The decagonal phase undergoes a eutectoid reaction to the three crystalline phases Al 3 Ni 2 , Al 3 Ni and Al 13 Fe 4 at 847 C. It melts peritectically at 930 C forming Al 13 Fe 4 , Al 3 Ni 2 and a liquid. The investigations in the Al-Cu-Ru system concentrated on the phase equilibria between the icosahedral phase and its neighbouring phases in a temperature range between 600 and 1000 C. The icosahedral phase was observed in the whole temperature range. The investigated stoichiometric area extends down to Al contents of 45%, which allows the fields of existence to be determined for the ternary phases α-AlCuRu, the icosahedral phase and Al 7 Cu 2 Ru. Binary phases were determined down to the upper (high Al content) border of AlRu. No hitherto unknown phase was observed in the investigated area. Rietveld analyses were carried out on α-AlCuRu and Al 7 Cu 2 Ru showing some discrepancies from the α-AlMnSi structure taken as a base for α-AlCuRu and confirming the Al 7 Cu 2 Fe structure for Al 7 Cu 2 Ru. (orig.)

  19. Strain ageing and yield plateau phenomena in γ-TiAl based alloys containing boron

    International Nuclear Information System (INIS)

    Cheng, T.T.; Bate, P.S.; Botten, R.R.; Lipsitt, H.A.

    1999-01-01

    There has been considerable interest over the past few years in γ-TiAl based alloys since they offer a combination of low density and useful mechanical properties at temperatures higher than those possible with conventional titanium alloys. However, there are still serious limitations to their use in engineering components due to their limited ductility and fracture toughness. Much of the recent work has been focused on improving the room temperature ductility of these materials, and a significant part of the work has been involved with studying the effects of thermo-mechanical processing (TMP) and alloying. One of the alloying additions which has received much attention is boron. Addition of boron (≥0.5 at.%) leads to refined as-cast grain structures and can increase the strength and ductility of these alloys. If boron does segregate to grain boundaries, it would be expected that segregation would also occur at dislocations, which can result in solute locking and yield point phenomena. Nakano and Umakoshi's results show some signs of this, with regions of distinct upward curvature in stress-strain curves for boron-containing material, although the flow stress was always increasing with strain. Evidence of strain ageing in TiAl alloys containing boron has also been reported by Wheeler et al., and the work reported here also suggests that boron can act to produce solute locking of glide dislocations in a different class of near γ-TiAl alloys

  20. Structural investigations of mechanical properties of Al based rapidly solidified alloys

    International Nuclear Information System (INIS)

    Karakoese, Ercan; Keskin, Mustafa

    2011-01-01

    Highlights: → Rapid solidification processing (RSP) involves exceptionally high cooling rates. → We correlate the microstructure of the intermetallic Al 3 Fe, Al 2 Cu and Al 3 Ni phases with the cooling rate. → The solidification rate is high enough to retain most of alloying elements in the Al matrix. → The rapid solidification has effect on the phase constitution. -- Abstract: In this study, Al based Al-3 wt.%Fe, Al-3 wt.%Cu and Al-3 wt.%Ni alloys were prepared by conventional casting. They were further processed using the melt-spinning technique and characterized by the X-ray diffraction (XRD), scanning electron microscopy (SEM) together with energy dispersive spectroscopy (EDS), transmission electron microscope (TEM), differential scanning calorimetry (DSC) and the Vickers microhardness tester. The rapidly solidified (RS) binary alloys were composed of supersaturated α-Al solid solution and finely dispersed intermetallic phases. Experimental results showed that the mechanical properties of RS alloys were enhanced, which can be attributed to significant changes in the microstructure. RS samples were measured using a microhardness test device. The dependence of microhardness H V on the solidification rate (V) was analysed. These results showed that with the increasing values of V, the values of H V increased. The enthalpies of fusion for the same alloys were determined by DSC.

  1. Depth of array micro-holes with large aspect ratio in Al based cast alloy

    Science.gov (United States)

    Jin, Meiling; Qu, Yingdong; Li, Rongde

    2018-03-01

    In order to study on the depth of array micro-holes on Al base cast alloy, micro-hole with depth of 50 mm and diameter of 0.55 mm are successfully prepared by using poor wetting between carbon and Al. Accordingly, the mold of depth is established, the results show that calculated depth of micro-hole is 53.22 mm, relative error is 6% compare with the actual measured depth, and the depth of hole exponentially increases with the increasing of distance between two micro-holes. Surface tension and metallostatic pressure of metal molten are mainly affecting factors for depth of micro-holes.

  2. Precipitation kinetics of lamellar (γ) laths in a TiAl-base alloy

    International Nuclear Information System (INIS)

    Zhang, W.J.; Francesconi, L.; Evangelista, E.

    1997-01-01

    Titanium aluminide is a candidate material for high temperature applications. Although different types of microstructure have been produced in TiAl-base alloys, the fully-lamellar structure is currently regarded as the most attractive. This kind of microstructure can be characterized by the factors, namely, colony size, lamellar interspacing, the existence of Widmanstatten (secondary) laths, and the type of grain boundaries (smooth or interlocking). The objective of this paper is to examine the nucleation and growth kinetics of γ lamellar laths during continuous and isothermal cooling. These data are expected to benefit the understanding of the transformation mechanism and the design of lamellar TiAl microstructure for industrial application

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

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

  4. High-temperature deformation of B2 NiAl-base alloys

    International Nuclear Information System (INIS)

    Lee, I.G.; Ghosh, A.K.

    1994-01-01

    The high-temperature deformation behavior of three rapidly solidified and processed NiAl-base alloys--NiAl, NiAl containing 2 pct TiB 2 , and NiAl containing 4 pct HfC--have been studied and their microstructural and textural changes during deformation characterized. Compressions tests were conducted at 1,300 and 1,447 K at strain rates ranging from 10 -6 to 10 -2 s -1 . HfC-containing material showed dispersion strengthening as well as some degree of grain refinement over NiAl, while TiB 2 dispersoid-containing material showed grain refinement as well as secondary recrystallization and did not improve high-temperature strength. Hot-pack rolling was also performed to develop thin sheet materials (1.27-mm thick) and from these alloys. Without dispersoids, NiAl rolled easily at 1,223 K and showed low flow stress and good ductility during the hot-rolling operation. Rolling of dispersoid-containing alloys was difficult due to strain localization and edge-cracking effects, resulting partly from the high flow stress at the higher strain rate during the rolling operation. Sheet rolling initially produced a {111} texture, which eventually broke into multiple-texture components with severe deformation

  5. Solute partitioning and interfacial segregation in TiAl-based alloys

    International Nuclear Information System (INIS)

    Larson, D.J.; Miller, M.K.

    1999-01-01

    Atom probe microscopy has been used to investigate elemental partitioning and segregation behavior in a TiAl-based alloy with a variety of alloying additions including Cr, Nb, W and B. These results indicate that in a stress-relieved state (2h at 900 C) and a reheated state (2h at 900 C, 2,184h at 800 C and 2h at 1,210 C) chromium, and to a lesser extent tungsten, is partitioned to the α 2 phase. However, in an annealed state (2h at 900 C and 720 h at 800 C), these elements are partitioned to the γ phase. Segregation of chromium and tungsten to lamellar interfaces is observed in the stress-relieved material, but significant segregation was not observed in material subjected to the other heat treatments. A W- and B-enriched precipitate was observed in the reheated material and provides a possible explanation for the low tungsten concentrations measured in the matrix phases

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

    International Nuclear Information System (INIS)

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

    1995-01-01

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

  7. Quasicrystalline phase formation in the mechanically alloyed Al{sub 70}Cu{sub 20}Fe{sub 10}

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, S. N. de, E-mail: snm@dfi.uem.br; Cadore, S.; Pereira, H. A.; Santos, I. A.; Colucci, C. C.; Paesano, A. [Universidade Estadual de Maringa, Departamento de Fisica (Brazil)

    2010-01-15

    In the present work, the formation of the Al{sub 70}Cu{sub 20}Fe{sub 10} icosahedral phase by mechanical alloying the elemental powders in a high-energy planetary mill was investigated by X-ray diffraction and Moessbauer spectroscopy. It was verified that the sample milled for 80 h produces an icosahedral phase besides Al(Cu, Fe) solid solution ({beta}-phase) and Al{sub 2}Cu intermetallic phase. The Moessbauer spectrum for this sample was fitted with a distribution of quadrupole splitting, a doublet and a sextet, revealing the presence of the icosahedral phase, {beta}-phase and {alpha}-Fe, respectively. This compound is not a good hydrogen storage. The results of the X-ray diffraction and Moessbauer spectroscopy of the sample milled for 40 h and annealed at 623 deg. C for 16 h shows essentially single i-phase and tetragonal Al{sub 7}Cu{sub 2} Fe phase.

  8. Oxide Dispersion Strengthened Fe(sub 3)Al-Based Alloy Tubes: Application Specific Development for the Power Generation Industry

    Energy Technology Data Exchange (ETDEWEB)

    Kad, B.K.

    1999-07-01

    A detailed and comprehensive research and development methodology is being prescribed to produce Oxide Dispersion Strengthened (ODS)-Fe3Al thin walled tubes, using powder extrusion methodologies, for eventual use at operating temperatures of up to 1100C in the power generation industry. A particular 'in service application' anomaly of Fe3Al-based alloys is that the environmental resistance is maintained up to 1200C, well beyond where such alloys retain sufficient mechanical strength. Grain boundary creep processes at such high temperatures are anticipated to be the dominant failure mechanism.

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

    Institute of Scientific and Technical Information of China (English)

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

    2001-01-01

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

  10. Hot-working behavior of an advanced intermetallic multi-phase γ-TiAl based alloy

    Energy Technology Data Exchange (ETDEWEB)

    Schwaighofer, Emanuel, E-mail: emanuel.schwaighofer@unileoben.ac.at [Department of Physical Metallurgy and Materials Testing, Montanuniversität Leoben, Roseggerstr. 12, A-8700 Leoben (Austria); Clemens, Helmut [Department of Physical Metallurgy and Materials Testing, Montanuniversität Leoben, Roseggerstr. 12, A-8700 Leoben (Austria); Lindemann, Janny [Chair of Physical Metallurgy and Materials Technology, Brandenburg University of Technology, Konrad-Wachsmann-Allee 17, D-03046 Cottbus (Germany); GfE Fremat GmbH, Lessingstr. 41, D-09599 Freiberg (Germany); Stark, Andreas [Institute of Materials Research, Helmholtz-Zentrum Geesthacht, Max-Planck-Str. 1, D-21502 Geesthacht (Germany); Mayer, Svea [Department of Physical Metallurgy and Materials Testing, Montanuniversität Leoben, Roseggerstr. 12, A-8700 Leoben (Austria)

    2014-09-22

    New high-performance engine concepts for aerospace and automotive application enforce the development of lightweight intermetallic γ-TiAl based alloys with increased high-temperature capability above 750 °C. Besides an increased creep resistance, the alloy system must exhibit sufficient hot-workability. However, the majority of current high-creep resistant γ-TiAl based alloys suffer from poor workability, whereby grain refinement and microstructure control during hot-working are key factors to ensure a final microstructure with sufficient ductility and tolerance against brittle failure below the brittle-to-ductile transition temperature. Therefore, a new and advanced β-solidifying γ-TiAl based alloy, a so-called TNM alloy with a composition of Ti–43Al–4Nb–1Mo–0.1B (at%) and minor additions of C and Si, is investigated by means of uniaxial compressive hot-deformation tests performed with a Gleeble 3500 simulator within a temperature range of 1150–1300 °C and a strain rate regime of 0.005–0.5 s{sup −1} up to a true deformation of 0.9. The occurring mechanisms during hot-working were decoded by ensuing constitutive modeling of the flow curves by a novel phase field region-specific surface fitting approach via a hyperbolic-sine law as well as by evaluation through processing maps combined with microstructural post-analysis to determine a safe hot-working window of the refined TNM alloy. Complementary, in situ high energy X-ray diffraction experiments in combination with an adapted quenching and deformation dilatometer were conducted for a deeper insight about the deformation behavior of the alloy, i.e. phase fractions and texture evolution as well as temperature uncertainties arising during isothermal and non-isothermal compression. It was found that the presence of β-phase and the contribution of particle stimulated nucleation of ζ-Ti{sub 5}Si{sub 3} silicides and h-type carbides Ti{sub 2}AlC enhance the dynamic recrystallization behavior during

  11. Hot-working behavior of an advanced intermetallic multi-phase γ-TiAl based alloy

    International Nuclear Information System (INIS)

    Schwaighofer, Emanuel; Clemens, Helmut; Lindemann, Janny; Stark, Andreas; Mayer, Svea

    2014-01-01

    New high-performance engine concepts for aerospace and automotive application enforce the development of lightweight intermetallic γ-TiAl based alloys with increased high-temperature capability above 750 °C. Besides an increased creep resistance, the alloy system must exhibit sufficient hot-workability. However, the majority of current high-creep resistant γ-TiAl based alloys suffer from poor workability, whereby grain refinement and microstructure control during hot-working are key factors to ensure a final microstructure with sufficient ductility and tolerance against brittle failure below the brittle-to-ductile transition temperature. Therefore, a new and advanced β-solidifying γ-TiAl based alloy, a so-called TNM alloy with a composition of Ti–43Al–4Nb–1Mo–0.1B (at%) and minor additions of C and Si, is investigated by means of uniaxial compressive hot-deformation tests performed with a Gleeble 3500 simulator within a temperature range of 1150–1300 °C and a strain rate regime of 0.005–0.5 s −1 up to a true deformation of 0.9. The occurring mechanisms during hot-working were decoded by ensuing constitutive modeling of the flow curves by a novel phase field region-specific surface fitting approach via a hyperbolic-sine law as well as by evaluation through processing maps combined with microstructural post-analysis to determine a safe hot-working window of the refined TNM alloy. Complementary, in situ high energy X-ray diffraction experiments in combination with an adapted quenching and deformation dilatometer were conducted for a deeper insight about the deformation behavior of the alloy, i.e. phase fractions and texture evolution as well as temperature uncertainties arising during isothermal and non-isothermal compression. It was found that the presence of β-phase and the contribution of particle stimulated nucleation of ζ-Ti 5 Si 3 silicides and h-type carbides Ti 2 AlC enhance the dynamic recrystallization behavior during deformation within

  12. Detection and distribution of lithium in Mg-Li-Al based alloy by ToF-SIMS

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Vinod, E-mail: vkt.meta@mnit.ac.in [Metallurgical and Materials Engineering, MNIT Jaipur, 302017 (India); Adjunct Faculty, Materials Research Centre, MNIT Jaipur, 302017 (India)

    2016-12-01

    Highlights: • First time, Time of Flight-Secondary Ion Mass Spectrometry (ToF-SIMS) is used to investigate the surface as well as bulk microstructural features of novel Mg-Li-Al based alloy. • There are six multi-oxide layers present within the surface film of LATZ9531R. • Secondary ion imaging by ToF-SIMS with mass contrast effect (including Li) is possible for a multiphase lithium-containing alloy systems. - Abstract: Time of Flight-Secondary Ion Mass Spectrometry (ToF-SIMS) is used to investigate the surface as well as bulk microstructural features of novel Mg-Li-Al based alloy namely Mg-9Li-7Al-3Sn-1Zn (LATZ9531). ToF-SIMS study indicates that there are six multi-oxide layers present within the surface film of LATZ9531. Furthermore, The presence of Li containing phase has been qualitatively confirmed based on the high number of Li-ion counts in SIMS, and the same is verified quantitatively by using electron probe microanalysis (EPMA). The novel approach may be useful to determine the chemical composition of the phases in various alloys which has lighter alloying elements such as lithium.

  13. Effect of hot rolling on the microstructure and mechanical properties of Ti3Al based dual phase alloys

    International Nuclear Information System (INIS)

    Wu, J.; Zhang, L.; Hua, W.; Qiu, G.

    1999-01-01

    Development of α 2 -Ti 3 Al based dual phase alloys have shown some promising potentials in property improvement by introducing Ti 5 Si 3 silicide phase into the matrix via Si alloying. However, the presence of coarse network of Ti 5 Si 3 phase formed by eutectic reaction in the as-cast state also embrittles the alloy. Both hot rolling and powder metallurgy are considered to be the possible ways to refine the Ti 5 Si 3 phase in the matrix. Two Ti-Al-Si-Nb alloys whose Si contents are 2 and 5 at.% respectively were arc melted into ingots and then hot rolled to sheets in this investigation. Optical metallographic examination correlates the microstructures of the as-cast and as-rolled alloys with the different rolling amounts, showing that the coarse silicide network is broken into small particles after hot rolling. Mechanical property testing from room temperature to 800 C indicates that the strength and plastic elongation of the hot-rolled alloys are much higher than those of the as-cast ones. The data obtained in this investigation are comparable with those obtained in the P/M processed specimens. Fracture surfaces of the alloys are also examined

  14. Work hardening characteristics in Al base alloys with 12.6 and 45 wt.% Zn

    International Nuclear Information System (INIS)

    Abd El-Salam, F.; Mostafa, M.M.; Wahab, L.A.; Mostafa, M.T.; Abd El-Aziz, Sh.M.

    2008-01-01

    The stress-strain curves were obtained for Al-Zn alloys of 12.6 wt.% Zn (alloy I) and 45 wt.% Zn (alloy II) with elements of purity (99.99). The monotonic shift of these curves towards lower flow stress and higher ductility was interrupted at the transformation temperatures 483 K (alloy I) and both 543, 603 K (alloy II). By increasing deformation temperature, Young's modulus, Y, yield and fracture stresses, σ y and σ f , respectively, fracture time, t f , the coefficient of parabolic work hardening, χ, decreased while fracture strain, ε f , and dislocation slip distance, L, increased. From the obtained X-rays diffraction patterns the lattice strain, ε, crystallite size, η, and dislocation density, ρ, were obtained at different deformation temperatures around transformation

  15. Hot Deformation Behavior and Pulse Current Auxiliary Isothermal Forging of Hot Pressing Sintering TiAl Based Alloys.

    Science.gov (United States)

    Shi, Chengcheng; Jiang, Shaosong; Zhang, Kaifeng

    2017-12-16

    This paper focuses on the fabrication of as-forged Ti46.5Al2Cr1.8Nb-(W, B) alloy via pulse current auxiliary isothermal forging (PCIF). The starting material composed of near gamma (NG) microstructure was fabricated by adopting pre-alloyed powders via hot pressing sintering (HPS) at 1300 °C. Isothermal compression tests were conducted at a strain rate range of 0.001-0.1 s -1 and a temperature range of 1125-1275 °C to establish the constitutive model and processing map. The optimal hot deformation parameters were successfully determined (in a strain rate range of 10 -3 -2.5 × 10 -3 s -1 and temperature range of 1130-1180 °C) based on the hot processing map and microstructure observation. Accordingly, an as-forged TiAl based alloy without cracks was successfully fabricated by PCIF processing at 1175 °C with a nominal strain rate of 10 -3 s -1 . Microstructure observation indicated that complete dynamic recrystallization (DRX) and phase transformation of γ→α₂ occurred during the PCIF process. The elongation of as-forged alloy was 136%, possessing a good secondary hot workability, while the sintered alloy was only 66% when tested at 900 °C with a strain rate of 2 × 10 -4 s -1 .

  16. Structural, electronic, magnetic and optical properties of Ni,Ti/Al-based Heusler alloys. A first-principles approach

    Energy Technology Data Exchange (ETDEWEB)

    Adebambo, Paul O. [Univ. of Agriculture. Abeokuta (Nigeria). Dept. of Physics; McPherson Univ., Abeokuta (Nigeria). Dept. of Physical and Computer Sciences; Adetunji, Bamidele I. [Univ. of Agriculture. Abeokuta (Nigeria). Dept. of Physics; Bells Univ. of Technology, Oto (Nigeria). Dept. of Mathematics; Olowofela, Joseph A. [Univ. of Agriculture. Abeokuta (Nigeria). Dept. of Physics; Oguntuase, James A. [Univ. of Agriculture. Abeokuta (Nigeria). Dept. of Mathematics; Adebayo, Gboyega A. [Univ. of Agriculture. Abeokuta (Nigeria). Dept. of Physics; Abdus Salam International Centre for Theoretical Physics, Trieste (Italy)

    2016-05-01

    In this work, detailed first-principles calculations within the generalised gradient approximation (GGA) of electronic, structural, magnetic, and optical properties of Ni,Ti, and Al-based Heusler alloys are presented. The lattice parameter of C1{sub b} with space group F anti 43m (216) NiTiAl alloys is predicted and that of Ni{sub 2}TiAl is in close agreement with available results. The band dispersion along the high symmetry points W→L→Γ→X→W→K in Ni{sub 2}TiAl and NiTiAl Heusler alloys are also reported. NiTiAl alloy has a direct band gap of 1.60 eV at Γ point as a result of strong hybridization between the d state of the lower and higher valence of both the Ti and Ni atoms. The calculated real part of the dielectric function confirmed the band gap of 1.60 eV in NiTiAl alloys. The present calculations revealed the paramagnetic state of NiTiAl. From the band structure calculations, Ni{sub 2}TiAl with higher Fermi level exhibits metallic properties as in the case of both NiAl and Ni{sub 3}Al binary systems.

  17. Composite material reinforced with atomized quasicrystalline particles and method of making same

    Science.gov (United States)

    Biner, S.B.; Sordelet, D.J.; Lograsso, B.K.; Anderson, I.E.

    1998-12-22

    A composite material comprises an aluminum or aluminum alloy matrix having generally spherical, atomized quasicrystalline aluminum-transition metal alloy reinforcement particles disposed in the matrix to improve mechanical properties. A composite article can be made by consolidating generally spherical, atomized quasicrystalline aluminum-transition metal alloy particles and aluminum or aluminum alloy particles to form a body that is cold and/or hot reduced to form composite products, such as composite plate or sheet, with interfacial bonding between the quasicrystalline particles and the aluminum or aluminum alloy matrix without damage (e.g. cracking or shape change) of the reinforcement particles. The cold and/or hot worked composite exhibits substantially improved yield strength, tensile strength, Young`s modulus (stiffness). 3 figs.

  18. Quasicrystalline structures and uses thereof

    Science.gov (United States)

    Steinhardt, Paul J; Chaikin, Paul Michael; Man, Weining

    2013-12-03

    This invention relates generally to the field of quasicrystalline structures. In preferred embodiments, the stopgap structure is more spherically symmetric than periodic structures facilitating the formation of stopgaps in nearly all directions because of higher rotational symmetries. More particularly, the invention relates to the use of quasicrystalline structures for optical, mechanical, electrical and magnetic purposes. In some embodiments, the invention relates to manipulating, controlling, modulating and directing waves including electromagnetic, sound, spin, and surface waves, for pre-selected range of wavelengths propagating in multiple directions.

  19. Martensitic Transformation and Superelasticity in Fe-Mn-Al-Based Shape Memory Alloys

    Science.gov (United States)

    Omori, Toshihiro; Kainuma, Ryosuke

    2017-12-01

    Ferrous shape memory alloys showing superelasticity have recently been obtained in two alloy systems in the 2010s. One is Fe-Mn-Al-Ni, which undergoes martensitic transformation (MT) between the α (bcc) parent and γ' (fcc) martensite phases. This MT can be thermodynamically understood by considering the magnetic contribution to the Gibbs energy, and the β-NiAl (B2) nanoprecipitates play an important role in the thermoelastic MT. The temperature dependence of critical stress for the MT is very small (about 0.5 MPa/°C) due to the small entropy difference between the parent and martensite phases in the Fe-Mn-Al-Ni alloy, and consequently, superelasticity can be obtained in a wide temperature range from cryogenic temperature to about 200 °C. Microstructural control is of great importance for obtaining superelasticity, and the relative grain size is among the most crucial factors.

  20. Ni.sub.3 Al-based intermetallic alloys having improved strength above 850.degree. C.

    Science.gov (United States)

    Liu, Chain T.

    2000-01-01

    Intermetallic alloys composed essentially of: 15.5% to 17.0% Al, 3.5% to 5.5% Mo, 4% to 8% Cr, 0.04% to 0.2% Zr, 0.04% to 1.5% B, balance Ni, are characterized by melting points above 1200.degree. C. and superior strengths at temperatures above 1000.degree. C.

  1. Molecular dynamics study of interstitial-solute interactions in irradiated Al-based alloys

    International Nuclear Information System (INIS)

    Doan, N.V.; Lam, N.Q.; Dagens, L.; Adda, Y.

    1981-11-01

    The stable configurations and binding energies of interstitial and di-interstitial-solute complexes in Al-Be, Al-Ca, Al-K, Al-Li, Al-Mg and Al-Zn alloys were calculated using the molecular dynamics technique in conjunction with interatomic potentials derived entirely from theoretical considerations and not fitted to any experimental data. All the results reported in this work are thus of first-principles nature

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-06-30

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

  3. High-temperature phase transformation in Cr added TiAl base alloy

    Energy Technology Data Exchange (ETDEWEB)

    Abe, E.; Niinobe, K.; Nobuki, M.; Nakamura, M.; Tsujimoto, T.

    1999-07-01

    The authors have investigated a microstructure evolution of a Ti-48Al-3.5Cr (in at.%) alloy at high-temperatures ({gt} 1,473K). In the alloy annealed at 1673K for 1.8ks, followed by air-cooling, a characteristic microstructure with a feathery fashion was uniformly formed. From a cooling-rate-controlling study, it was found that formation of the feathery structure is accomplished during continuous cooling from 1673K to 1573K, within the {alpha} + {gamma} two-phase region. Transmission electron microscopy revealed that the feathery structure is composed of lamellar colonies (5--10{micro}m) which are crystallographically tilted slightly (a few degree) with their neighbors. A surprising fact is that lamellae in each colony are mostly the {gamma} phase with few {alpha}{sub 2} phase less than 5% in volume. This suggests that the feathery structure is a metastable product and has not resulted from the {alpha} {r{underscore}arrow} {alpha} + {gamma} transformation above 1,573 K. Instead, the feathery structure formation should be attributed to the non-equilibrium {alpha} {r{underscore}arrow} {gamma} transformation which occurs at high-temperatures with a small degree of supercooling. The authors discuss this interesting phase transformation in terms of the {alpha} {r{underscore}arrow} {gamma} massive transformation, based on the continuous-cooling-transformation (CCT) diagram constructed for the present alloy.

  4. Preferential site occupancy of alloying elements in TiAl-based phases

    Energy Technology Data Exchange (ETDEWEB)

    Holec, David, E-mail: david.holec@unileoben.ac.at; Reddy, Rajeev K.; Klein, Thomas; Clemens, Helmut [Department of Physical Metallurgy and Materials Testing, Montanuniversität Leoben, Franz-Josef-Strasse 18, A-8700 Leoben (Austria)

    2016-05-28

    First principles calculations are used to study the preferential occupation of ternary alloying additions into the binary Ti-Al phases, namely, γ-TiAl, α{sub 2}-Ti{sub 3}Al, β{sub o}-TiAl, and B19-TiAl. While the early transition metals (TMs, group IVB, VB, and VIB elements) prefer to substitute for Ti atoms in the γ-, α{sub 2}-, and B19-phases, they preferentially occupy Al sites in the β{sub o}-TiAl. Si is, in this context, an anomaly, as it prefers to sit on the Al sublattice for all four phases. B and C are shown to prefer octahedral Ti-rich interstitial positions instead of substitutional incorporation. The site preference energy is linked with the alloying-induced changes of energy of formation, hence alloying-related (de)stabilisation of the phases. We further show that the phase-stabilisation effect of early TMs on β{sub o}-phase has a different origin depending on their valency. Finally, an extensive comparison of our predictions with available theoretical and experimental data (which is, however, limited mostly to the γ-phase) shows a consistent picture.

  5. Corrosion Mechanisms in Brazed Al-Base Alloy Sandwich Structures as a Function of Braze Alloy and Process Variables

    Science.gov (United States)

    2013-02-01

    concerns. These braze alloys use a high Si content to produce a low melting Al-Si near eutectic alloy. The recommended 11 brazing temperature for A A...each successive dip enhancing the 21 high temperature Si enrichment outside of the braze gap and decreasing the Si content within the braze gap.6...Nevertheless equilibrium phases should be considered as a reference point for grain boundaries after high temperature brazing . Recent literature [22

  6. Microstructure and mechanical properties of Mg–Al-based alloy modified with cerium

    Energy Technology Data Exchange (ETDEWEB)

    Chaubey, A.K., E-mail: anil.immt@gmail.com [Institute of Minerals and Materials Technology (IMMT), Bhubaneswar 751013 (India); Scudino, S.; Prashanth, K.G. [IFW Dresden, Institut für Komplexe Materialien, Postfach 270116, D-01171 Dresden (Germany); Eckert, J. [IFW Dresden, Institut für Komplexe Materialien, Postfach 270116, D-01171 Dresden (Germany); TU Dresden, Institut für Werkstoffwissenschaft, D-01062 Dresden (Germany)

    2015-02-11

    Mg{sub 90}Al{sub 10–x}Ce{sub x} with x=0, 1, 3 and 5 (at%) have been prepared by copper mold casting and the influence of Ce on the microstructure and mechanical properties have been investigated. The addition of 1% Ce decreases the volume fraction of the γ-Mg{sub 17}Al{sub 12} phase and with the further increase of Ce to 3% and 5%, the γ-Mg{sub 17}Al{sub 12} intermetallic disappears completely with the formation of the Al{sub 11}Ce{sub 3} and Al{sub 2}Ce intermetallic phases. The room temperature compression tests show that Ce addition significantly improves the room temperature mechanical properties. For example, the alloy with 5% Ce displays a strength of 448 MPa compared to 318 MPa of the binary Ce-free alloy along with appreciable plasticity of about 9%. This improvement is due to grain refinement as well as to the precipitation of the Al{sub 11}Ce{sub 3} and Al{sub 2}Ce strengthening phases.

  7. The Mechanisms of Dispersion Strengthening and Fracture in Al-based XD (TM) Alloys

    Science.gov (United States)

    Aiken, R. M., Jr.

    1990-01-01

    The influence of reinforcement size, volume fraction, and matrix deformation behavior on room and elevated temperature strength, and the fracture toughness of metal matrix composites of both pure aluminum and Al(4 percent)Cu(1.5 percent)Mg with 0 to 15 vol percent TiB2 were examined. Higher TiB2 volume fractions increased the tensile yield strength both at room and elevated temperatures, and reduced the elongation to fracture. Tensile tests also indicate that small particles provided a greater increase in strength for a given volume fraction than larger particles, whereas elongation to fracture appeared to be insensitive to reinforcement size. The fracture toughness of the Al(4 percent)Cu(1.5 percent)Mg alloys decreased rapidly with TiB2 additions of 0 to 5 vol percent and more slowly with TiB2 additions of 5 to 15 vol percent. Fracture toughness appears to be independent of TiB2 particle size. The isothermal-aging response of the precipitation strengthened Al(4 percent)Cu(1.5 percent)Mg alloys was not altered by the presence of TiB2.

  8. High strength nanostructured Al-based alloys through optimized processing of rapidly quenched amorphous precursors.

    Science.gov (United States)

    Kim, Song-Yi; Lee, Gwang-Yeob; Park, Gyu-Hyeon; Kim, Hyeon-Ah; Lee, A-Young; Scudino, Sergio; Prashanth, Konda Gokuldoss; Kim, Do-Hyang; Eckert, Jürgen; Lee, Min-Ha

    2018-01-18

    We report the methods increasing both strength and ductility of aluminum alloys transformed from amorphous precursor. The mechanical properties of bulk samples produced by spark-plasma sintering (SPS) of amorphous Al-Ni-Co-Dy powders at temperatures above 673 K are significantly enhanced by in-situ crystallization of nano-scale intermetallic compounds during the SPS process. The spark plasma sintered Al 84 Ni 7 Co 3 Dy 6 bulk specimens exhibit 1433 MPa compressive yield strength and 1773 MPa maximum strength together with 5.6% plastic strain, respectively. The addition of Dy enhances the thermal stability of primary fcc Al in the amorphous Al-TM -RE alloy. The precipitation of intermetallic phases by crystallization of the remaining amorphous matrix plays important role to restrict the growth of the fcc Al phase and contributes to the improvement of the mechanical properties. Such fully crystalline nano- or ultrafine-scale Al-Ni-Co-Dy systems are considered promising for industrial application because their superior mechanical properties in terms of a combination of very high room temperature strength combined with good ductility.

  9. Microstructure and mechanical properties of Mg–Al-based alloy modified with cerium

    International Nuclear Information System (INIS)

    Chaubey, A.K.; Scudino, S.; Prashanth, K.G.; Eckert, J.

    2015-01-01

    Mg 90 Al 10–x Ce x with x=0, 1, 3 and 5 (at%) have been prepared by copper mold casting and the influence of Ce on the microstructure and mechanical properties have been investigated. The addition of 1% Ce decreases the volume fraction of the γ-Mg 17 Al 12 phase and with the further increase of Ce to 3% and 5%, the γ-Mg 17 Al 12 intermetallic disappears completely with the formation of the Al 11 Ce 3 and Al 2 Ce intermetallic phases. The room temperature compression tests show that Ce addition significantly improves the room temperature mechanical properties. For example, the alloy with 5% Ce displays a strength of 448 MPa compared to 318 MPa of the binary Ce-free alloy along with appreciable plasticity of about 9%. This improvement is due to grain refinement as well as to the precipitation of the Al 11 Ce 3 and Al 2 Ce strengthening phases

  10. Solidification of Undercooled Melts of Al-Based Alloys on Earth and in Space

    Science.gov (United States)

    Herlach, Dieter M.; Burggraf, Stefan; Galenko, Peter; Gandin, Charles-André; Garcia-Escorial, Asuncion; Henein, Hani; Karrasch, Christian; Mullis, Andrew; Rettenmayr, Markus; Valloton, Jonas

    2017-08-01

    Containerless processing of droplets and drops by atomization and electromagnetic levitation are applied to undercool metallic melts and alloys prior to solidification. Heterogeneous nucleation on crucible walls is completely avoided giving access to large undercoolings. Experiments are performed both under terrestrial (1 g) conditions and in reduced gravity ( µg) as well. Microgravity conditions are realized by the free fall of small droplets during atomization of a spray of droplets, individual drops in a drop tube and by electromagnetic levitation of drops during parabolic flights, sounding rocket missions, and using the electro-magnetic levitator multi-user facility on board the International Space Station. The comparison of both sets of experiments in 1 g and µg leads to an estimation of the influence of forced convection on dendrite growth kinetics and microstructure evolution.

  11. Amorphous and nanocrystalline phase formation in highly-driven Al-based binary alloys

    International Nuclear Information System (INIS)

    Kalay, Yunus Eren

    2008-01-01

    Remarkable advances have been made since rapid solidification was first introduced to the field of materials science and technology. New types of materials such as amorphous alloys and nanostructure materials have been developed as a result of rapid solidification techniques. While these advances are, in many respects, ground breaking, much remains to be discerned concerning the fundamental relationships that exist between a liquid and a rapidly solidified solid. The scope of the current dissertation involves an extensive set of experimental, analytical, and computational studies designed to increase the overall understanding of morphological selection, phase competition, and structural hierarchy that occurs under far-from equilibrium conditions. High pressure gas atomization and Cu-block melt-spinning are the two different rapid solidification techniques applied in this study. The research is mainly focused on Al-Si and Al-Sm alloy systems. Silicon and samarium produce different, yet favorable, systems for exploration when alloyed with aluminum under far-from equilibrium conditions. One of the main differences comes from the positions of their respective T 0 curves, which makes Al-Si a good candidate for solubility extension while the plunging T 0 line in Al-Sm promotes glass formation. The rapidly solidified gas-atomized Al-Si powders within a composition range of 15 to 50 wt% Si are examined using scanning and transmission electron microscopy. The non-equilibrium partitioning and morphological selection observed by examining powders at different size classes are described via a microstructure map. The interface velocities and the amount of undercooling present in the powders are estimated from measured eutectic spacings based on Jackson-Hunt (JH) and Trivedi-Magnin-Kurz (TMK) models, which permit a direct comparison of theoretical predictions. For an average particle size of 10 (micro)m with a Peclet number of ∼0.2, JH and TMK deviate from each other. This

  12. Amorphous and nanocrystalline phase formation in highly-driven Al-based binary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kalay, Yunus Eren [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    Remarkable advances have been made since rapid solidification was first introduced to the field of materials science and technology. New types of materials such as amorphous alloys and nanostructure materials have been developed as a result of rapid solidification techniques. While these advances are, in many respects, ground breaking, much remains to be discerned concerning the fundamental relationships that exist between a liquid and a rapidly solidified solid. The scope of the current dissertation involves an extensive set of experimental, analytical, and computational studies designed to increase the overall understanding of morphological selection, phase competition, and structural hierarchy that occurs under far-from equilibrium conditions. High pressure gas atomization and Cu-block melt-spinning are the two different rapid solidification techniques applied in this study. The research is mainly focused on Al-Si and Al-Sm alloy systems. Silicon and samarium produce different, yet favorable, systems for exploration when alloyed with aluminum under far-from equilibrium conditions. One of the main differences comes from the positions of their respective T0 curves, which makes Al-Si a good candidate for solubility extension while the plunging T0 line in Al-Sm promotes glass formation. The rapidly solidified gas-atomized Al-Si powders within a composition range of 15 to 50 wt% Si are examined using scanning and transmission electron microscopy. The non-equilibrium partitioning and morphological selection observed by examining powders at different size classes are described via a microstructure map. The interface velocities and the amount of undercooling present in the powders are estimated from measured eutectic spacings based on Jackson-Hunt (JH) and Trivedi-Magnin-Kurz (TMK) models, which permit a direct comparison of theoretical predictions. For an average particle size of 10 {micro}m with a Peclet number of ~0.2, JH and TMK deviate from

  13. Formation of less-known structurally complex ζb and orthorhombic quasicrystalline approximant εn on solidification of selected Al–Pd–Cr alloys

    Czech Academy of Sciences Publication Activity Database

    Adamech, A.; Černičková, I.; Ďuriška, L.; Kolesár, V.; Drienovský, M.; Bednarčík, J.; Svoboda, Milan; Janovec, J.

    2014-01-01

    Roč. 97, NOV (2014), s. 189-198 ISSN 1044-5803 Institutional support: RVO:68081723 Keywords : complex metallic alloys * aluminium alloys * intermetallics Subject RIV: JG - Metallurgy Impact factor: 1.845, year: 2014

  14. In situ synchrotron x-ray characterization of microstructure formation in solidification processing of Al-based metallic alloys

    International Nuclear Information System (INIS)

    Billia, Bernard; Nguyen-Thi, Henri; Mangelinck-Noel, Nathalie

    2010-01-01

    The microstructure formed during the solidification step has a major influence on the properties of materials processed by major techniques (casting, welding ...). In situ and real-time characterization by synchrotron X-ray imaging is the method of choice to unveil the dynamical formation of the solidification microstructure in metallic alloys, and thus provide precise data for the critical validation of the theoretical predictions that is needed for sound advancement of modeling and numerical simulation. After a description of the experimental procedure used at the European Synchrotron Radiation Facility (ESRF), dynamical phenomena in the formation of the grain structure and dendritic or equiaxed solidification microstructure in Al-based alloys are presented. Beyond fluid flow interaction, earth gravity induces stresses, deformation and fragmentation in the dendritic mush. Settling of dendrite arms and equiaxed grains thus occurs, in particular in the columnar to equiaxed transition. Other types of stresses and strains are caused by the mere formation of the solidification microstructure itself. In white-beam X-ray topography, stresses and strains are manifested by specific contrasts and breaking of the Laue images into several pieces. Finally, quantitative analysis of the grey level in radiographs enables the analysis of solute segregation, which noticeably results in solutal poisoning of growth when equiaxed grains are interacting. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-06-30

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

  16. Quasicrystalline metallic adlayers

    Indian Academy of Sciences (India)

    ugc

    diffraction pattern of icosahedral phase Al-. 14 at. % Mn alloys along fivefold axis. Discovery of ... Al-Mn-Si,Al-Cu-Ru,Al-Pd-Re, Al-Ni-Co, Cd-Yb, Al-Ni-Co….) Al. 63. Cu ... structure and physical properties is not easy Need for quasicrystals with.

  17. Strain accumulation in quasicrystalline solids

    International Nuclear Information System (INIS)

    Nori, F.; Ronchetti, M.; Elser, V.

    1988-01-01

    We study the relaxation of 2D quasicrystalline elastic networks when their constituent bonds are perturbed homogeneously. Whereas ideal, quasiperiodic networks are stable against such perturbations, we find significant accumulations of strain in a class of disordered networks generated by a growth process. The grown networks are characterized by root mean square phason fluctuations which grow linearly with system size. The strain accumulation we observe in these networks also grows linearly with system size. Finally, we find a dependence of strain accumulation on cooling rate

  18. Diamagnetism in quasicrystalline superconducting networks

    International Nuclear Information System (INIS)

    Qian Niu; Nori, F.

    1990-01-01

    In this paper, we review recent results on superconducting structures with quasicrystalline geometry. Specifically, we consider the superconducting-normal phase boundaries of a variety of wire networks and Josephson junction arrays. We have computed the mean field phase diagrams for a number of geometries and compared them to the corresponding experimental data. We have introduced an analytical approach to the analysis of the structures present in the phase boundaries. Furthermore, we have shown in great detail how the gross structure is determined by the statistical distributions of the cell areas, and how the fine structures are determined by correlations among neighboring cells in the lattices. (author). 12 refs, 2 figs

  19. Oxide Dispersion Strengthened Fe3Al-Based Alloy Tubes: Application Specific Development for the Power Generation Industry

    Energy Technology Data Exchange (ETDEWEB)

    Kad, B.K.

    2002-02-08

    A detailed and comprehensive research and development methodology is being prescribed to produce Oxide Dispersion Strengthened (ODS)-Fe{sub 3}Al thin walled tubes, using powder extrusion methodologies, for eventual use at operating temperatures of up to 1100% in the power generation industry. A particular ''in service application'' anomaly of Fe{sub 3}Al-based alloys is that the environmental resistance is maintained up to 1200 C, well beyond where such alloys retain sufficient mechanical strength. Grain boundary creep processes at such high temperatures are anticipated to be the dominant failure mechanism. Thus, the challenges of this program are manifold: (1) to produce thin walled ODS-Fe{sub 3}Al tubes, employing powder extrusion methodologies, with (2) adequate increased strength for service at operating temperatures, and (3) to mitigate creep failures by enhancing the as-processed grain size in ODS-Fe{sub 3}Al tubes. Our research progress till date has resulted in the successful batch production of typically 8 Ft. lengths of 1-3/8 inch diameter, 1/8 inch wall thickness, ODS-Fe{sub 3}Al tubes via a proprietary single step extrusion consolidation process. The process parameters for such consolidation methodologies have been prescribed and evaluated as being routinely reproducible. Such processing parameters (i.e., extrusion ratios, temperature, can design etc.) were particularly guided by the need to effect post-extrusion recrystallization and grain growth at a sufficiently low temperature, while still meeting the creep requirement at service temperatures. Static recrystallization studies show that elongated grains (with their long axis parallel to the extrusion axis), typically 200-2000 {micro}m in diameter, and several millimeters long can be obtained routinely, at 1200 C. The growth kinetics are affected by the interstitial impurity content in the powder batches. For example complete recrystallization, across the tube wall thickness, is

  20. Effect of thermal fatigue on the structure and properties of Ni3Al-based alloy single crystals

    Science.gov (United States)

    Povarova, K. B.; Drozdov, A. A.; Bazyleva, O. A.; Bulakhtina, M. A.; Alad'ev, N. A.; Antonova, A. V.; Arginbaeva, E. G.; Morozov, A. E.

    2014-05-01

    The effect of thermal fatigue during tests of and single crystals according to the schedules 100 ai 850°C, 100 ai 1050°C, 100 ai 1100°C at a peak-to-peak stress Δσtc = 700-1000 MPa (sum of the maximum tensile and compressive stresses in a thermal cycle) on the structure, the fracture, and the fatigue life of an Ni3Al-based VKNA-1V alloy is studied. It is found that, at 103 thermal cycles, the single crystals have the maximum thermal fatigue resistance at the maximum cycle temperature of 850 and 1050°C, and the properties of the and samples are almost the same at the maximum thermal cycle temperature of 1100°C. After thermal cycling at the maximum temperature of 850°C, the γ layers in the two-phase γ' + γ region in dendrites remain a single-phase structure, as in the as-cast material, and the layer thickness is 100-150 nm. When the maximum thermal cycle temperature increases to 1050 or 1100°C, the discontinuous γ-phase layers in the γ'(Ni3Al) matrix change their morphology and become shorter and wider (their thickness is 300-700 nm). The nickel-based supersaturated solid solution in these layers decomposes with the formation of secondary γ'(Ni3Al)-phase (γ'sec) precipitates in the form of cuboids 50 and 100 nm in size at the maximum cycle temperature of 1050 and 1100°C, respectively. The alternating stresses that appear during thermal cycling cause plastic deformation. As in nickel superalloys, this deformation at the first stage proceeds via the slip of screw dislocations along octahedral {111} planes. Networks of 60° dislocation segments form at γ'/γ interfaces in this case. Fracture begins at the lines of intersection of the slip planes of the {111} octahedron with the sample surface. During fractional, a crack passes from one octahedral plane to another and forms terraces and steps (crystallographic fracture); as a result, the fracture surface bends and becomes curved. In all cases, the fracture surfaces have a mixed brittle-ductile character

  1. Application of computational thermodynamics to the determination of thermophysical properties as a function of temperature for multicomponent Al-based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Fabiana C. [Fluminense Federal University, Graduate Program in Metallurgical Engineering, Av. dos Trabalhadores, 420-27255-125 Volta Redonda, RJ (Brazil); Paresque, Mara C.C. [Fluminense Federal University, Graduate Program in Mechanical Engineering, Av. dos Trabalhadores, 420-27255-125 Volta Redonda, RJ (Brazil); Castro, José A. de [Fluminense Federal University, Graduate Program in Metallurgical Engineering, Av. dos Trabalhadores, 420-27255-125 Volta Redonda, RJ (Brazil); Jácome, Paulo A.D. [Fluminense Federal University, Graduate Program in Mechanical Engineering, Av. dos Trabalhadores, 420-27255-125 Volta Redonda, RJ (Brazil); Garcia, Amauri, E-mail: amaurig@fem.unicamp.br [University of Campinas – UNICAMP, Department of Manufacturing and Materials Engineering, 13083-860 Campinas, SP (Brazil); Ferreira, Ivaldo L. [Fluminense Federal University, Graduate Program in Mechanical Engineering, Av. dos Trabalhadores, 420-27255-125 Volta Redonda, RJ (Brazil)

    2015-11-10

    Highlights: • A model coupled to a computational thermodynamics software is proposed to compute thermophysical properties. • The model applies to multicomponent alloys and has been validated against experimental results. • Density and specific heat as a function of temperature are computed for Al–Si–Cu alloys. - Abstract: Despite the technological importance of Al–Si–Cu alloys in manufacturing processes involving heat transfer, such as welding, casting and heat treatment, thermophysical properties of this system of alloys are very scarce in the literature. In this paper, a model connected to a computational thermodynamics software is proposed permitting density and specific heats as a function of temperature and enthalpy of transformations to be numerically determined. The model is pre-validated against experimental density as a function of temperature for liquid and solid phases of A319 and 7075 alloys found in the literature and validated against experimental density values for the solid phase of an Al-6 wt%Cu-1 wt%Si alloy determined in the present study. In both cases the numerical predictions are in good agreement with the experimental results. Specific heat and temperatures and heats of transformation are also numerically determined for this ternary Al-based alloy.

  2. Application of computational thermodynamics to the determination of thermophysical properties as a function of temperature for multicomponent Al-based alloys

    International Nuclear Information System (INIS)

    Nascimento, Fabiana C.; Paresque, Mara C.C.; Castro, José A. de; Jácome, Paulo A.D.; Garcia, Amauri; Ferreira, Ivaldo L.

    2015-01-01

    Highlights: • A model coupled to a computational thermodynamics software is proposed to compute thermophysical properties. • The model applies to multicomponent alloys and has been validated against experimental results. • Density and specific heat as a function of temperature are computed for Al–Si–Cu alloys. - Abstract: Despite the technological importance of Al–Si–Cu alloys in manufacturing processes involving heat transfer, such as welding, casting and heat treatment, thermophysical properties of this system of alloys are very scarce in the literature. In this paper, a model connected to a computational thermodynamics software is proposed permitting density and specific heats as a function of temperature and enthalpy of transformations to be numerically determined. The model is pre-validated against experimental density as a function of temperature for liquid and solid phases of A319 and 7075 alloys found in the literature and validated against experimental density values for the solid phase of an Al-6 wt%Cu-1 wt%Si alloy determined in the present study. In both cases the numerical predictions are in good agreement with the experimental results. Specific heat and temperatures and heats of transformation are also numerically determined for this ternary Al-based alloy.

  3. Development of aero-space structural Ni3Al-based alloys for service at temperature above 1000 oC in air without protection coating

    International Nuclear Information System (INIS)

    Kablov, E.N.; Buntushkin, V.P.; Povarova, K.B.; Kasanskaya, N.K.

    2001-01-01

    The principles of alloying are developed for alloys based on the γ' phase Ni 3 Al and realized for the design of a high-temperature alloy VKNA-1V destined for a wide range of 'hot' GTE articles (e.g., flaps, nozzle vanes, turbine rotor blades, elements of flame tubes, and other complex thin-wall articles) produced by vacuum investment casting. Owing to a fortunate combination of the selected boron-free alloying system (Ni-AI-Cr-W-Mo-Zr-C), the presence of a ductile structure constituent such as nickel-based γ solid solution (∼10 wt%) and directed columnar or single crystal structure the alloy is characterized by high ductility at room (El=14-35 %), middle and high temperatures (El=18-31 % at 673-1473 K), by a melting temperature (solidus) as high as T m = 1613 K, a density of at most 7930 kg /m 3 , high short term and long term strength at temperatures 1273-1573 K (σ 100 =110 MPa at 1373 K). Alloy has a high oxidation resistance at temperatures up to 1573 K and is resistant to stress corrosion and general atmospheric corrosion. New VKNA-1V Ni 3 Al-based alloy with equiaxed grained, directional solidification (DS), or single crystal structures can be produced by conventional cast processes used for investment casting of nickel superalloys, including the process of high-gradient DS. Compared to nickel analogs, the alloy is relatively cheap and do not need in protective coating up to 1573 K in air. (author)

  4. Advancement of Compositional and Microstructural Design of Intermetallic γ-TiAl Based Alloys Determined by Atom Probe Tomography

    Science.gov (United States)

    Klein, Thomas; Clemens, Helmut; Mayer, Svea

    2016-01-01

    Advanced intermetallic alloys based on the γ-TiAl phase have become widely regarded as most promising candidates to replace heavier Ni-base superalloys as materials for high-temperature structural components, due to their facilitating properties of high creep and oxidation resistance in combination with a low density. Particularly, recently developed alloying concepts based on a β-solidification pathway, such as the so-called TNM alloy, which are already incorporated in aircraft engines, have emerged offering the advantage of being processible using near-conventional methods and the option to attain balanced mechanical properties via subsequent heat-treatment. Development trends for the improvement of alloying concepts, especially dealing with issues regarding alloying element distribution, nano-scale phase characterization, phase stability, and phase formation mechanisms demand the utilization of high-resolution techniques, mainly due to the multi-phase nature of advanced TiAl alloys. Atom probe tomography (APT) offers unique possibilities of characterizing chemical compositions with a high spatial resolution and has, therefore, been widely used in recent years with the aim of understanding the materials constitution and appearing basic phenomena on the atomic scale and applying these findings to alloy development. This review, thus, aims at summarizing scientific works regarding the application of atom probe tomography towards the understanding and further development of intermetallic TiAl alloys. PMID:28773880

  5. Construction and evaluation of multi-component Zn-Al based bearing alloys (Zn-Al-Si, Zn-Al-Cu)

    International Nuclear Information System (INIS)

    Shahmiri, M.; Shahin, K.

    2001-01-01

    Zn-Al based alloys, with excellent mechanical properties, are finding increasing applications in various industries, especially bearing and bushing fields. Observed dimensional instabilities, in their multicomponent systems, (e. g. Zn-Al-Si and, Zn-Al Si-Cu), is believed to be as the result of some kinds of phase transformation, due to the temperature variations, while in service. Profound understanding of the phase transformations due to the temperature variation, requires detailed evaluations of the isothermal sections of the multi-components phase diagrams of Zn-Al-Si and, Zn-Al-Si-Cu alloy systems. In the present article, the isothermal sections of the aforementioned ternary and quaternary systems in the solid state regions have been investigated and observed phase transitions have been critically evaluated

  6. Scanning electron microscopy and transmission electron microscopy study of hot-deformed gamma-TiAl-based alloy microstructure.

    Science.gov (United States)

    Chrapoński, J; Rodak, K

    2006-09-01

    The aim of this work was to assess the changes in the microstructure of hot-deformed specimens made of alloys containing 46-50 at.% Al, 2 at.% Cr and 2 at.% Nb (and alloying additions such as carbon and boron) with the aid of scanning electron microscopy and transmission electron microscopy techniques. After homogenization and heat treatment performed in order to make diverse lamellae thickness, the specimens were compressed at 1000 degrees C. Transmission electron microscopy examinations of specimens after the compression test revealed the presence of heavily deformed areas with a high density of dislocation. Deformation twins were also observed. Dynamically recrystallized grains were revealed. For alloys no. 2 and no. 3, the recovery and recrystallization processes were more extensive than for alloy no. 1.

  7. Nanoquasicrystalline Al–Fe–Cr–Nb alloys produced by powder metallurgy

    Energy Technology Data Exchange (ETDEWEB)

    Audebert, F., E-mail: metal@fi.uba.ar [Advanced Materials Group, Facultad de Ingeniería, Universidad de Buenos Aires. Paseo Colón 850, Buenos Aires 1063 (Argentina); Department of Materials, University of Oxford, Parks Road, OX1 3PH Oxford (United Kingdom); Galano, M. [Department of Materials, University of Oxford, Parks Road, OX1 3PH Oxford (United Kingdom); Rios, C. Triveño; Kasama, H.; Peres, M.; Kiminami, C.; Botta, W.J.; Bolfarini, C. [Departamento de Engenharia de Materiais, Universidade Federal de São Carlos. Rodovia Washington Luiz, km 235, 13.565-905, PO Box 676, São Carlos, SP (Brazil)

    2013-11-15

    Highlights: •The feasibility to produce nanoquasicrystalline Al–Fe–Cr–Nb bars was investigated. •Refined microstructures were obtained for a melt atomization temperature >1250 °C. •Icosahedral particles were obtained in atomized powder sizes under 75 μm. •Large fraction of icosahedral particles can be retained in bars extruded at 375 °C. •Nanoquasicrystalline bars showed high ability to retain high strength at 250 °C. -- Abstract: Nano-quasicrystalline Al–Fe–Cr based alloys produced by rapid solidification processes exhibit high strength at elevated temperatures. Nevertheless, the quasicrystalline particles in these systems become unstable at high temperature limiting the industrial applications. In early works, it was observed that the use of Nb or Ta increases the stability of the Al–Fe–Cr quasicrystalline phase delaying the microstructural transformation to higher temperatures. Thus, these nano-quasicrystalline Al-based alloys have become promising new high strength material to be used at elevated temperatures in the automotive and aeronautical industries. In previous works, nano-quasicrystalline Al–Fe–Cr–Nb based alloys were obtained by rapid solidification using the melt-spinning technique. In order to obtain bulk alloys for industrial applications other fabrication routes such as powder production by gas atomization followed by compaction and extrusion are required. In the present work, the production of Al–Fe–Cr–Nb based alloys by powder atomization at laboratory scale was investigated. The powders obtained were sieved in different ranges of sizes and the microstructures were characterised by means of X-ray diffraction, scanning and transmission electron microscopy, and energy dispersive of X-ray analysis. Mechanical properties have been measured by compression tests at room temperature and at 250 °C. It was observed that a very high temperature is required to produce these alloys by gas atomization; the icosahedral

  8. Nanoquasicrystalline Al–Fe–Cr–Nb alloys produced by powder metallurgy

    International Nuclear Information System (INIS)

    Audebert, F.; Galano, M.; Rios, C. Triveño; Kasama, H.; Peres, M.; Kiminami, C.; Botta, W.J.; Bolfarini, C.

    2013-01-01

    Highlights: •The feasibility to produce nanoquasicrystalline Al–Fe–Cr–Nb bars was investigated. •Refined microstructures were obtained for a melt atomization temperature >1250 °C. •Icosahedral particles were obtained in atomized powder sizes under 75 μm. •Large fraction of icosahedral particles can be retained in bars extruded at 375 °C. •Nanoquasicrystalline bars showed high ability to retain high strength at 250 °C. -- Abstract: Nano-quasicrystalline Al–Fe–Cr based alloys produced by rapid solidification processes exhibit high strength at elevated temperatures. Nevertheless, the quasicrystalline particles in these systems become unstable at high temperature limiting the industrial applications. In early works, it was observed that the use of Nb or Ta increases the stability of the Al–Fe–Cr quasicrystalline phase delaying the microstructural transformation to higher temperatures. Thus, these nano-quasicrystalline Al-based alloys have become promising new high strength material to be used at elevated temperatures in the automotive and aeronautical industries. In previous works, nano-quasicrystalline Al–Fe–Cr–Nb based alloys were obtained by rapid solidification using the melt-spinning technique. In order to obtain bulk alloys for industrial applications other fabrication routes such as powder production by gas atomization followed by compaction and extrusion are required. In the present work, the production of Al–Fe–Cr–Nb based alloys by powder atomization at laboratory scale was investigated. The powders obtained were sieved in different ranges of sizes and the microstructures were characterised by means of X-ray diffraction, scanning and transmission electron microscopy, and energy dispersive of X-ray analysis. Mechanical properties have been measured by compression tests at room temperature and at 250 °C. It was observed that a very high temperature is required to produce these alloys by gas atomization; the icosahedral

  9. Heat affected zone microfissuring in a laser beam welded directionally solidified Ni3Al-base alloy

    International Nuclear Information System (INIS)

    Ojo, O.A.; Ding, R.G.; Chaturvedi, M.C.

    2006-01-01

    The laser beam weld heat affected zone (HAZ) microstructure of a newly developed aerospace alloy, IC 6, was examined. HAZ microfissuring was observed and found to be associated with grain boundary liquation facilitated by subsolidus eutectic-type transformation of the alloy's major phase, γ' precipitates, and interfacial melting of M 6 C-type carbide and (Mo 2 Ni)B 2 -type boride particles

  10. Preliminary Analysis of the General Performance and Mechanical Behavior of Irradiated FeCrAl Base Alloys and Weldments

    Energy Technology Data Exchange (ETDEWEB)

    Gussev, Maxim N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Briggs, Samuel A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yamamoto, Yukinori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-30

    The iron-based, iron-chromium-aluminum (FeCrAl) alloys are promising, robust materials for deployment in current and future nuclear power plants. This class of alloys demonstrates excellent performance in a range of environments and conditions, including high-temperature steam (>1000°C). Furthermore, these alloys have the potential to have prolonged survival under loss-of-coolant accident (LOCA) conditions compared to the more traditional cladding materials that are either Zr-based alloys or austenitic steels. However, one of the issues associated with FeCrAl alloys is cracking during welding. The present project investigates the possibility of mitigating welding-induced cracking via alloying and precise structure control of the weldments; in the frame work of the project, several advanced alloys were developed and are being investigated prior to and after neutron irradiation to provide insight into the radiation tolerance and mechanical performance of the weldments. The present report provides preliminary results on the post-irradiation characterization and mechanical tests performed during United States Fiscal Year (FY) 2016. Chapter 1 provides a general introduction, and Chapter 2 describes the alloy compositions, welding procedure, specimen geometry and manufacturing parameters. Also, a brief discussion of the irradiation at the High Flux Isotope Reactor (HFIR) is provided. Chapter 3 is devoted to the analysis of mechanical tests performed at the hot cell facility; tensile curves and mechanical properties are discussed in detail focusing on the irradiation temperature. Limited fractography results are also presented and analyzed. The discussion highlights the limitations of the testing within a hot cell. Chapter 4 underlines the advantages of in-situ testing and discusses the preliminary results obtained with newly developed miniature specimens. Specimens were moved to the Low Activation Materials Development and Analysis (LAMDA) laboratory and prepared for

  11. Fusion zone microstructure of laser beam welded directionally solidified Ni3Al-base alloy IC6

    International Nuclear Information System (INIS)

    Ding, R.G.; Ojo, O.A.; Chaturvedi, M.C.

    2006-01-01

    The fusion zone microstructure of laser welded alloy IC6 was examined. Extensive weld-metal cracking was observed to be closely associated with non-equilibrium eutectic-type microconstituents identified as consisting of γ, γ' and NiMo (Y) phases. Their formation has been related to modification of primary solidification path due to reduced solutal microsegregation

  12. New phenomena in epitaxial growth: solid films on quasicrystalline substrates

    International Nuclear Information System (INIS)

    Fournee, V; Thiel, P A

    2005-01-01

    An overview is given of the research conducted in the field of solid film growth on quasiperiodic surfaces. An atomistic description of quasicrystalline surfaces is presented and discussed in relation to bulk structural models. The various systems for which thin film growth has been attempted so far are reviewed. Emphasis is placed on the nucleation mechanisms of the solid films, on their growth modes in relation to the nature of the deposited metals, on the possibility of intermixing or alloying at the interface and on the epitaxial relationships at the crystal-quasicrystal interfaces. We also describe situations where the deposited elements adopt a quasiperiodic structure, which opens up the possibility of extending our understanding of the relation between quasiperiodicity and the physical properties of such structurally and chemically complex solids. (topical review)

  13. In Situ Synthesis of Al-Based MMCs Reinforced with AlN by Mechanical Alloying under NH3 Gas

    Directory of Open Access Journals (Sweden)

    E. S. Caballero

    2018-05-01

    Full Text Available Aluminum matrix composites (AMCs reinforced by aluminum nitride were prepared by mechanical alloying followed by a simple press and sintering method. Milling began under vacuum and after a period of between 1 and 4 h, NH3 gas flow (1 cm3/s was incorporated until the total milling time of 5 h was reached. Results show that in addition to the strain hardening taking place during mechanical alloying, NH3 plays an additional role in powder hardening. Thereby, the properties of the sintered compacts are strongly influenced by the amount of N incorporated into the powders during milling and the subsequent formation of AlN during the consolidation process. The obtained AMC reaches tensile strengths as high as 459 MPa and hardness much higher than that of the as-received aluminum compact.

  14. The mechanisms of dispersion strengthening and fracture in Al-based XD(tm) alloys, part 1

    Science.gov (United States)

    Aikin, R. M., Jr.

    1990-01-01

    The influence of reinforcement size, volume fraction, and matrix deformation behavior on room and elevated temperature strength; the fracture toughness; and the fatigue crack growth rate of metal matrix composites of Al-4(pct)Cu-1.5(pct)Mg with TiB2 were examined. The influence of reinforcement volume fraction was also examined for pure aluminum with TiB2. Higher TiB2 volume fractions increased the tensile yield strength at both room and elevated temperatures, and reduced the elongation to fracture. Tensile tests also indicate that small particles provided a greater increase in strength for a given volume fraction than larger particles, whereas elongation to fracture appeared to be insensitive to reinforcement size. Interparticle spacing appears to be the factor that controls the strength of these alloys, with the exact nature of the dependence relying on the nature of dislocation slip in the matrix (planar vs. diffuse). The isothermal aging response of the precipitation strengthened Al-4(pct)Cu-1.5(pct)Mg alloys was not accelerated by the presence of TiB2. Cold work prior to artificial aging created additional geometrically necessary dislocations which serve as heterogeneous nucleation sites leading to accelerated aging, a finer precipitate size, and an increase in the strength of the alloy.

  15. Phase equilibria among α-Fe(Al, Cr, Ti), liquid and TiC and the formation of TiC in Fe3Al-based alloys

    International Nuclear Information System (INIS)

    Kobayashi, Satoru; Schneider, Andre; Zaefferer, Stefan; Frommeyer, Georg; Raabe, Dierk

    2005-01-01

    In the context of the development of high-strength Fe 3 Al-based alloys, phase equilibria among α-Fe(Al, Cr, Ti), liquid and TiC phases in the Fe-Al-Cr-Ti-C quinary system and the formation of TiC were determined. A pseudo-eutectic trough (L α + L + TiC) exists at 1470 deg C at around Fe-26Al-5Cr-2Ti-1.7C on the vertical section between Fe-26Al-5Cr (α) and Ti-46C (TiC) in at.%. Large faceted TiC precipitates form from the melt after the formation of primary α phase even in hypoeutectic alloys. The TiC formation is thought to be due to the composition change of the liquid towards the hypereutectic compositions by solidification of the primary α. In order to remove the faceted TiC, which are unfavourable for strengthening the material, two different processing routes have been successfully tested: (i) solidification with an increased rate to reduce the composition variation of the liquid during solidification, and (ii) unidirectional solidification to separate the light TiC precipitates from the melt

  16. Investigation of orientation gradients around a hard Laves particle in a warm-rolled Fe3Al-based alloy using a 3D EBSD-FIB technique

    International Nuclear Information System (INIS)

    Konrad, J.; Zaefferer, S.; Raabe, D.

    2006-01-01

    We present a study of the microstructure around a hard Laves particle in a warm-rolled intermetallic Fe 3 Al-based alloy. The experiments are conducted using a system for three-dimensional orientation microscopy (3D electron backscattering diffraction, EBSD). The approach is realized by a combination of a focused ion beam (FIB) unit for serial sectioning with high-resolution field emission scanning electron microscopy with EBSD. We observe the formation of steep 3D orientation gradients in the Fe 3 Al matrix around the rigid precipitate which entail in part particle-stimulated nucleation events in the immediate vicinity of the particle. The orientation gradients assume a characteristic pattern around the particle in the transverse plane while revealing an elongated tubular morphology in the rolling direction. However, they do not reveal a characteristic common rotation axis. Recovered areas in the matrix appear both in the transverse and rolling directions around the particle. The work demonstrates that the new 3D EBSD-FIB technique provides a new level of microstructure information that cannot be achieved by conventional 2D-EBSD analysis

  17. Periodically distributed objects with quasicrystalline diffraction pattern

    Energy Technology Data Exchange (ETDEWEB)

    Wolny, Janusz, E-mail: wolny@fis.agh.edu.pl; Strzalka, Radoslaw [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Krakow (Poland); Kuczera, Pawel [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Krakow (Poland); Laboratory of Crystallography, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zurich (Switzerland)

    2015-03-30

    It is possible to construct fully periodically distributed objects with a diffraction pattern identical to the one obtained for quasicrystals. These objects are probability distributions of distances obtained in the statistical approach to aperiodic structures distributed periodically. The diffraction patterns have been derived by using a two-mode Fourier transform—a very powerful method not used in classical crystallography. It is shown that if scaling is present in the structure, this two-mode Fourier transform can be reduced to a regular Fourier transform with appropriately rescaled scattering vectors and added phases. Detailed case studies for model sets 1D Fibonacci chain and 2D Penrose tiling are discussed. Finally, it is shown that crystalline, quasicrystalline, and approximant structures can be treated in the same way.

  18. Design and fabrication of a mechanical alloying system for preparing intermetallic, nanocrystalline, amorphous and quasicrystalline compounds; Diseno y fabricacion de un sistema de aleado mecanico para preparar compuestos intermetalicos, nanocristalinos, amorfos y cuasicristalinos

    Energy Technology Data Exchange (ETDEWEB)

    Bonifacio M, J.; Iturbe G, J.L.; Castaneda J, G. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2002-07-01

    In this work a grinding system was designed and fabricated which allowed to improve the operation conditions in time, frequency, temperature and selection of the grinding media and that allow the contamination decrease of the compounds. By means of this method of mechanical alloying new metallic compounds can be produced, starting from elemental powders, with fine and controlled microstructures. These compounds prepared by this method are going to be used as materials for the hydrogen storage. (Author)

  19. Structures and Electrochemical Hydrogen Storage Properties of the As-Spun RE-Mg-Ni-Co-Al-Based AB2-Type Alloys Applied to Ni-MH Battery

    Science.gov (United States)

    Zhang, Yanghuan; Yuan, Zeming; Shang, Hongwei; Li, Yaqin; Qi, Yan; Zhao, Dongliang

    2017-05-01

    In this paper, the La0.8- x Ce0.2Y x MgNi3.5Co0.4Al0.1 ( x = 0, 0.05, 0.1, 0.15, 0.2) alloys were synthesized via smelting and melt spinning. The effect of Y content on the structure and electrochemical hydrogen storage characteristics of the as-cast and spun alloys was investigated. The identifications of XRD and SEM demonstrate that the experimental alloys possess a major phase LaMgNi4 and a minor phase LaNi5. The variation of Y content results in an obvious transformation of the phase abundance rather than phase composition in the alloys, namely LaMgNi4 phase increases while LaNi5 phase decreases with Y content growing. Furthermore, the replacement of Y for La causes the lattice constants and cell volume to clearly decrease and markedly refines the alloy grains. The electrochemical tests reveal that these alloys can obtain the maximum values of discharge capacity at the first cycling without any activation needed. With Y content growing, the discharge capacity of the alloys obviously declines, but its cycle stability remarkably improves. Moreover, the electrochemical dynamics of the alloys, involving the high-rate discharge ability, hydrogen diffusion coefficient ( D), limiting current density ( I L), and charge transfer rate, initially augment and then decrease with rising Y content.

  20. Direct preparation of Al-base alloys from their oxides/metal precursors in the eutectic LiCl–KCl melt

    International Nuclear Information System (INIS)

    Gao, Bingliang; Zhu, Hao; Xia, Yuxiang; Shi, Zhongning; Hu, Xianwei; Wang, Zhaowen

    2016-01-01

    A study was carried out on the preparation of Al–Cu–Li alloy from their oxides/metal precursors using the method of electro-deoxidation in the eutectic LiCl–KCl melt at 648 K. Cyclic voltammetry was used to characterize the system. The samples were prepared by potentiostatic electrolysis at −1.0 V to −2.0 V (vs. Ag + /Ag) for 5 h. XRD analysis shows that Li 2 O is not electrochemically reduced to Li at −1.0 V (vs. Ag + /Ag) or more negative potential. During the preparation process of Al–Cu–Li alloy, lithium peroxide is formed as an intermediate compound. Al–Cu–Li alloy is chemically prepared through the reaction between aluminum and lithium peroxide by heating of Al–Cu–Li 2 O precursors in KCl–LiCl–LiF melt at 1023 K. Eelectro-deoxidation in LiCl–KCl melt can increase the lithium content in the final alloy product. Al–Mg and Al–Nd alloy were also prepared by using the same method from their mixture of aluminum and corresponding oxide, respectively. Al–Nd alloy can only be obtained at the temperature above 773 K. Al–Li alloy could not be obtained in eutectic CaCl 2 –LiCl melt because of formation of calcium aluminates. - Highlights: • Al–Cu–Li alloy was prepared using electrochemical deoxidation of Al–Cu–Li 2 O precursor in eutectic KCl–LiCl melt at 648 K. • Al–Nd alloy was successfully produced by the same method at 773 K. • CaCl 2 –LiCl melt is not a good choice for preparing Al–Li alloy because of formation of calcium aluminate.

  1. Direct preparation of Al-base alloys from their oxides/metal precursors in the eutectic LiCl–KCl melt

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Bingliang, E-mail: blgao@mail.neu.edu.cn; Zhu, Hao; Xia, Yuxiang; Shi, Zhongning; Hu, Xianwei; Wang, Zhaowen

    2016-04-25

    A study was carried out on the preparation of Al–Cu–Li alloy from their oxides/metal precursors using the method of electro-deoxidation in the eutectic LiCl–KCl melt at 648 K. Cyclic voltammetry was used to characterize the system. The samples were prepared by potentiostatic electrolysis at −1.0 V to −2.0 V (vs. Ag{sup +}/Ag) for 5 h. XRD analysis shows that Li{sub 2}O is not electrochemically reduced to Li at −1.0 V (vs. Ag{sup +}/Ag) or more negative potential. During the preparation process of Al–Cu–Li alloy, lithium peroxide is formed as an intermediate compound. Al–Cu–Li alloy is chemically prepared through the reaction between aluminum and lithium peroxide by heating of Al–Cu–Li{sub 2}O precursors in KCl–LiCl–LiF melt at 1023 K. Eelectro-deoxidation in LiCl–KCl melt can increase the lithium content in the final alloy product. Al–Mg and Al–Nd alloy were also prepared by using the same method from their mixture of aluminum and corresponding oxide, respectively. Al–Nd alloy can only be obtained at the temperature above 773 K. Al–Li alloy could not be obtained in eutectic CaCl{sub 2}–LiCl melt because of formation of calcium aluminates. - Highlights: • Al–Cu–Li alloy was prepared using electrochemical deoxidation of Al–Cu–Li{sub 2}O precursor in eutectic KCl–LiCl melt at 648 K. • Al–Nd alloy was successfully produced by the same method at 773 K. • CaCl{sub 2}–LiCl melt is not a good choice for preparing Al–Li alloy because of formation of calcium aluminate.

  2. Consolidation of mechanically milled powder mixture of aluminum and quasicrystalline particle; Mechanical milling shita junkessho ryushi / aluminium gokin funmatsu no koka seikeisei

    Energy Technology Data Exchange (ETDEWEB)

    Yuasa, E.; Kawamura, C.; Sugiyama, T. [Musashi Institute of Technology, Tokyo (Japan)

    1998-10-15

    A quasi-crystalline Al65Cu20Fe15 powder prepared from alloy cast rapidly solidified by metal-mold casting, and then it was mixed to aluminum powder with various volume fractions by mechanical milling. The powder milled for above 50ks made homogeneous dispersion of quasi-crystalline phase with particle size less than 1{mu}m. The powder was hot-pressed under various conditions and then its features of consolidation were examined by the observation of microstructure and fracture strength in 3-point-bending of the compacts. When the milled powder was hot-pressed at higher compacting temperature than 673K for 3.6ks under pressure of 600MPa, the compact became to dense. Hardness of the obtained compact increases and its fracture strength decreases with increasing volume fraction of quasi-crystalline particles. Intermetallic compound Al7Cu2Fe forms in the interface of aluminum matrix and quasi-crystalline particle. 11 refs., 10 figs.

  3. Fabrication of ten-fold photonic quasicrystalline structures

    Directory of Open Access Journals (Sweden)

    XiaoHong Sun

    2015-05-01

    Full Text Available Compared to periodic crystals, quasicrystals have higher point group symmetry and are more favorable in achieving complete band-gaps. In this report, a top-cut prism interferometer is designed to fabricate ten-fold photonic quasicrystalline structures. By optimizing the exposing conditions and material characteristics, appropriate quasicrystals have been obtained in the SU8 photoresist films. Atomic Force Microscopy and laser diffraction are used to characterize the fabricated structures. The measurement results show the consistence between the theoretical design and experiments. This will provide guidance for the large-area and fast production of ten-fold quasicrystalline structures with high quality.

  4. Simulation of the precipitation process of ordered intermetallic compounds in binary and ternary Ni-Al-based alloys by the phase-field model

    International Nuclear Information System (INIS)

    Hou Hua; Zhao Yuhong; Zhao Yuhui

    2009-01-01

    With the microscopic phase-field model, atomic-scale computer simulation programs for the precipitation mechanism of the ordered intermetallic compound γ' in binary Ni-15.5 at.%Al alloy, θ and γ' in ternary Ni 75 Al x V 25-x alloys were worked out based on the microscopic diffusion equation and non-equilibrium free energy. The simulation can be applied to the whole precipitation process and composition range. A prior assumptions on the new phase structure or transformation path was unnecessary, the possible non-equilibrium phases, atomic clustering and ordering could be described automatically, and atomic images, order parameters and volume fractions of precipitates were obtained. Computer simulation was performed systematically on the precipitation mechanism, precipitation sequence of θ and γ' in complicated system with ordering and clustering simultaneously. Through the simulated atomic images and chemical order parameters of precipitates, we can explain the complex precipitation mechanisms of θ (Ni 3 V) and γ' (Ni 3 Al) ordered phases. For the binary alloy, the precipitation mechanism of γ' phase has the characteristic of both non-classical nucleation and growth (NCNG) and congruent ordering and spinodal decomposition (COSD). For the ternary alloys, the precipitation characteristic of γ' phase transforms from NCNG to COSD gradually, otherwise, the precipitation characteristic of θ phase transforms from COSD to NCNG mechanism gradually

  5. Phase-field simulations of dendrite morphologies and selected evolution of primary {alpha}-Mg phases during the solidification of Mg-rich Mg-Al-based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Mingyue [Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Jing, Tao; Liu, Baicheng [Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China)

    2009-10-15

    A formulation of solid-liquid interfacial thermodynamic and kinetic anisotropic characteristics for hexagonal close-packed metals is proposed. The two- and three-dimensional dendritic growth of primary Mg in undercooled Mg-Al alloy melts is modeled using the phase-field method, based on a combination of crystallographic lattice symmetry and experimental observations. The morphologies of three-dimensional dendrites are obtained and the calculated results show intricately hierarchical branched structures. The excess free energy of the solution system is based on the Redlich-Kister model.

  6. Phase-field simulations of dendrite morphologies and selected evolution of primary α-Mg phases during the solidification of Mg-rich Mg-Al-based alloys

    International Nuclear Information System (INIS)

    Wang, Mingyue; Jing, Tao; Liu, Baicheng

    2009-01-01

    A formulation of solid-liquid interfacial thermodynamic and kinetic anisotropic characteristics for hexagonal close-packed metals is proposed. The two- and three-dimensional dendritic growth of primary Mg in undercooled Mg-Al alloy melts is modeled using the phase-field method, based on a combination of crystallographic lattice symmetry and experimental observations. The morphologies of three-dimensional dendrites are obtained and the calculated results show intricately hierarchical branched structures. The excess free energy of the solution system is based on the Redlich-Kister model.

  7. Structure of nanocomposites of Al–Fe alloys prepared by ...

    Indian Academy of Sciences (India)

    Wintec

    This difference in the product structure can be attributed to the difference in alloying mechanisms in MA and RSP. Keywords. Nanocomposites; Al–Fe; mechanical alloying; rapid solidification; quasicrystalline. 1. Introduction. Al–Fe alloys are attractive for applications at temperatures beyond those normally associated with ...

  8. Microstructure and wear behaviour of FeAl-based composites ...

    Indian Academy of Sciences (India)

    FeAl-based composites; precipitation; mechanical properties; wear. 1. Introduction. Fe–Al alloys ... ground to 1500 grit and polished with alumina powder. (0.5 μm). ... Alloy-2 (figure 2) consists of cuboid-shaped ZrC (region C), an FeAl matrix ...

  9. Visible diffraction from quasi-crystalline arrays of carbon nanotubes

    Science.gov (United States)

    Butler, Timothy P.; Butt, Haider; Wilkinson, Timothy D.; Amaratunga, Gehan A. J.

    2015-08-01

    Large area arrays of vertically-aligned carbon nanotubes (VACNTs) are patterned in a quasi-crystalline Penrose tile arrangement through electron beam lithography definition of Ni catalyst dots and subsequent nanotube growth by plasma-enhanced chemical vapour deposition. When illuminated with a 532 nm laser beam high-quality and remarkable diffraction patterns are seen. The diffraction is well matched to theoretical calculations which assume apertures to be present at the location of the VACNTs for transmitted light. The results show that VACNTs act as diffractive elements in reflection and can be used as spatially phased arrays for producing tailored diffraction patterns.

  10. Optical metamaterials with quasicrystalline symmetry: symmetry-induced optical isotropy

    International Nuclear Information System (INIS)

    Kruk, S.S.; Decker, M.; Helgert, Ch.; Neshev, D.N.; Kivshar, Y.S.; Staude, I.; Powell, D.A.; Pertsch, Th.; Menzel, Ch.; Helgert, Ch.; Etrich, Ch.; Rockstuhl, C.; Menzel, Ch.

    2013-01-01

    Taking advantage of symmetry considerations, we have analyzed the potential of various metamaterials to affect the polarization state of light upon oblique illumination. We have shown that depending on the angle of illumination, metamaterials are able to support specific polarization states. The presented methodology that using ellipticity and circular dichroism, provides an unambiguous language for discussing the impact of the inherent symmetry of the metamaterial lattices on their far-field response. Our findings allow the quantification analysis of the impact of inter-element coupling and lattice symmetry on the optical properties of metamaterials, and to separate this contribution from the response associated with a single meta-atom. In addition, we have studied the concept of optical quasicrystalline metamaterials, revealing that the absence of translational symmetry (periodicity) of quasicrystalline metamaterials causes an isotropic optical response, while the long-range positional order preserves the resonance properties. Our findings constitute an important step towards the design of optically isotropic metamaterials and metasurfaces. (authors)

  11. Covalent bonds and their crucial effects on pseudogap formation in α-Al(Mn,Re)Si icosahedral quasicrystalline approximant

    International Nuclear Information System (INIS)

    Kirihara, K.; Nagata, T.; Kimura, K.; Kato, K.; Takata, M.; Nishibori, E.; Sakata, M.

    2003-01-01

    X-ray charge densities of Al-based icosahedral quasicrystalline approximant crystals α-AlReSi, α-AlMnSi, and Al 12 Re were observed by a combination of the maximum entropy method with the Rietveld method. We successfully obtained the clear images of interatomic covalent bonds between Al and transition metals (Mn, Re) and those in the Al (or Si) icosahedron in Mackay icosahedral clusters of both α-AlReSi and α-AlMnSi approximant crystals. The bonding nature of the three kinds of glue atom sites connecting Mackay icosahedral clusters was also clarified. This covalent bonding nature should strongly relate with the enhancement of the electron density-of-states pseudogap near the Fermi level. In addition, the interatomic covalent bonds of α-AlReSi are stronger than those of α-AlMnSi. This fact leads to the low effective carrier density of α-AlReSi in comparison with that of α-AlMnSi. Unlike the covalent bonding nature of an icosahedron in α-AlReSi and α-AlMnSi crystals, the Al icosahedron with an Re center atom exhibits no Al-Al interatomic covalent bonds in the Al 12 Re crystal. The tendency for metallic-covalent bonding conversion in the Al icosahedron, which is related to the atom site occupancy of the icosahedral cluster center, is also strongly supported

  12. High temperature oxidation behavior of TiAl-based intermetallics

    International Nuclear Information System (INIS)

    Stroosnijder, M.F.; Sunderkoetter, J.D.; Haanappel, V.A.C.

    1996-01-01

    TiAl-based intermetallic compounds have attracted considerable interest as structural materials for high-temperature applications due to their low density and substantial mechanical strength at high temperatures. However, one major drawback hindering industrial application arises from the insufficient oxidation resistance at temperatures beyond 700 C. In the present contribution some general aspects of high temperature oxidation of TiAl-based intermetallics will be presented. This will be followed by a discussion of the influence of alloying elements, in particular niobium, and of the effect of nitrogen in the oxidizing environment on the high temperature oxidation behavior of such materials

  13. Superconducting-normal phase boundary of quasicrystalline arrays in a magnetic field

    International Nuclear Information System (INIS)

    Nori, F.; Niu, Q.; Fradkin, E.; Chang, S.

    1987-01-01

    We study the effect of frustration, induced by a mangnetic field, on the superconducting diamagnetic properties of two-dimensional quasicrystalline arrays. In particular, we calculate the superconducting-normal phase boundary, T/sub c/(H), for several geometries with quasicrystalline order. The agreement between our theoretically obtained phase boundaries and the experimentally obtained ones is very good. We also propose a new way of analytically analyzing the overall and the fine structure of T/sub c/(H) in terms of short- and long-range correlations among tiles

  14. Corrosion behavior of Mg–5Al based magnesium alloy with 1 wt.% Sn, Mn and Zn additions in 3.5 wt.% NaCl solution

    Directory of Open Access Journals (Sweden)

    Nguyen Dang Nam

    2014-06-01

    Full Text Available The corrosion properties of four Mg–5Al alloys with M-alloying elements (tin, manganese and zinc in a 3.5 wt.% NaCl solution were examined using electrochemical tests and surface analyses. The electrochemical results indicated that the addition of 1 wt.% M metal decreased the corrosion rate and hydrogen evolution rate of the Mg–5Al specimens. Moreover, the addition of 1Zn resulted in having the best corrosion resistance due to the interaction of Zn oxide with Mg and Al oxides which acted as a corrosion barrier.

  15. Crystalline and quasicrystalline allotropes of Pb formed on the fivefold surface of icosahedral Ag-In-Yb

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, H. R., E-mail: H.R.Sharma@liv.ac.uk; Smerdon, J. A.; Nugent, P. J.; Ribeiro, A.; McGrath, R. [Surface Science Research Centre and Department of Physics, The University of Liverpool, Liverpool L69 3BX (United Kingdom); McLeod, I.; Dhanak, V. R. [Department of Physics and the Stephenson Institute for Renewable Energy, The University of Liverpool, Liverpool L69 3BX (United Kingdom); Shimoda, M. [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Tsai, A. P. [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577 (Japan)

    2014-05-07

    Crystalline and quasicrystalline allotropes of Pb are formed by evaporation on the fivefold surface of the icosahedral (i) Ag-In-Yb quasicrystal under ultra-high vacuum. Lead grows in three dimensional quasicrystalline order and subsequently forms fivefold-twinned islands with the fcc(111) surface orientation atop of the quasicrystalline Pb. The islands exhibit specific heights (magic heights), possibly due to the confinement of electrons in the islands. We also study the adsorption behavior of C{sub 60} on the two allotropes of Pb. Scanning tunneling microcopy reveals that a high corrugation of the quasicrystalline Pb limits the diffusion of the C{sub 60} molecules and thus produces a disordered film, similar to adsorption behavior of the same molecules on the clean substrate surface. However, the sticking coefficient of C{sub 60} molecules atop the Pb islands approaches zero, regardless of the overall C{sub 60} coverage.

  16. Quasi-crystalline and disordered photonic structures fabricated using direct laser writing

    Science.gov (United States)

    Sinelnik, Artem D.; Pinegin, Konstantin V.; Bulashevich, Grigorii A.; Rybin, Mikhail V.; Limonov, Mikhail F.; Samusev, Kirill B.

    2017-09-01

    Direct laser writing is a rapid prototyping technology that has been utilized for the fabrication of micro- and nano-scale materials that have a perfect structure in most of the cases. In this study we exploit the direct laser writing to create several classes of non-periodic materials, such as quasi-crystalline lattices and three-dimensional (3D) objects with an orientation disorder in structural elements. Among quasi-crystalline lattices we consider Penrose tiling and Lévy-type photonic glasses. Images of the fabricated structures are obtained with a scanning electron microscope. In experiment we study the optical diffraction from 3D woodpile photonic structures with orientation disorder and analyze diffraction patters observed on a flat screen positioned behind the sample. With increasing of the disorder degree, we find an impressive transformation of the diffraction patterns from perfect Laue picture to a speckle pattern.

  17. Effects of Nb addition on icosahedral quasicrystalline phase formation and glass-forming ability of Zr--Ni--Cu--Al metallic glasses

    International Nuclear Information System (INIS)

    Fan, Cang; Li, Chunfei; Inoue, Akihisa; Haas, Volker

    2001-01-01

    This work shows that the crystallization process of Zr--Ni--Cu--Al metallic glass is greatly influenced by adding Nb as an alloying element. Based on the results of the differential scanning calorimetry experiments for metallic glasses Zr 69-x Nb x Ni 10 Cu 12 Al 9 (x=0--15at.%), the crystallization process takes place through two individual stages. For Zr 69 Ni 10 Cu 12 Al 9 (x=0), metastable hexagonal ω-Zr and a small fraction of tetragonal Zr 2 Cu are precipitated upon completion of the first exothermic reaction. Contrary to this alloy, the precipitation of a nanoquasicrystalline phase is detected when 5--10 at.% Nb is added. Furthermore, the crystallization temperature T x , supercooled liquid region ΔT x and reduced temperature T g /T L (T g is the glass transition temperature, T L the liquidus temperature) increase with increasing Nb content. These results indicate that adding Nb content to Zr--Ni--Cu--Al metallic glasses not only induces quasicrystalline phase formation, but also enhances glass-forming ability. Copyright 2001 American Institute of Physics

  18. Micromechanisms of fracture and fatigue in Ti3Al based and TiAl based intermetallics

    International Nuclear Information System (INIS)

    James, A.W.; Chave, R.A.; Hippsley, C.A.; Bowen, P.

    1993-01-01

    Micromechanisms of fracture and fatigue crack growth resistance in specific Ti 3 Al based and TiAl based intermetallics are reviewed. Effects of test temperature, environment and microstructure on crack growth resistance are considered in detail for several Ti 3 Al and Ti'Al based intermetallic systems under development. The implications of these studies for the structural reliability of these materials is also addressed briefly. (orig.)

  19. Optimal width of quasicrystalline slabs of dielectric cylinders to microwave radiation transmission contrast

    Energy Technology Data Exchange (ETDEWEB)

    Andueza, Ángel; Sevilla, Joaquín [Dpto. Ing. Eléctrica y Electrónica Universidad Pública de Navarra, 31006 Pamplona (Spain); Smart Cities Institute, Universidad Pública de Navarra, 31006 Pamplona (Spain); Wang, Kang [Laboratoire de Physique des Solides, UMR CNRS/Université Paris-Sud, Université Paris-Saclay, 91405 Orsay (France); Pérez-Conde, Jesús [Dpto. de Física Universidad Pública de Navarra, 31006 Pamplona (Spain)

    2016-08-28

    Light confinement induced by resonant states in aperiodic photonic structures is interesting for many applications. A particular case of these resonances can be found in 2D quasicrystalline arrangements of dielectric cylinders. These systems present a rather isotropic band gap as well as isolated in-gap photonic states (as a result of spatially localized resonances). These states are built by high symmetry polygonal clusters that can be regarded as photonic molecules. In this paper, we study the transmission properties of a slab of glass cylinders arranged in approximants of the decagonal quasicrystalline structure. In particular, we investigate the influence of the slab width in the transmission contrast between the states and the gap. The study is both experimental and numerical in the microwave regime. We find that the best transmission contrast is found for a width of around three times the radiation wavelength. The transmission in the band gap region is mediated by the resonances of the photonic molecules. If the samples are thin enough, they become transparent except around a resonance of the photonic molecule which reflects the incoming light.

  20. Quasicrystalline Approach to Prediting the Spinel-Nepheline Liquidus: Application to Nuclear Waste Glass Processing

    Energy Technology Data Exchange (ETDEWEB)

    Jantzen, Carol

    2005-10-10

    The crystal-melt equilibria in complex fifteen component melts are modeled based on quasicrystalline concepts. A pseudobinary phase diagram between acmite (which melts incongruently to a transition metal ferrite spinel) and nepheline is defined. The pseudobinary lies within the Al{sub 2}O{sub 3}-Fe{sub 2}O{sub 3}-Na{sub 2}O-SiO{sub 2} quaternary system that defines the crystallization of basalt glass melts. The pseudobinary provides the partitioning of species between the melt and the primary liquidus phases. The medium range order of the melt and the melt-crystal exchange equilibria are defined based on a constrained mathematical treatment that considers the crystallochemical coordination of the elemental species in acmite and nepheline. The liquidus phases that form are shown to be governed by the melt polymerization and the octahedral site preference energies. This quasicrystalline liquidus model has been used to prevent unwanted crystallization in the world's largest high level waste (HLW) melter for the past three years while allowing >10 wt% higher waste loadings to be processed.

  1. Evidence of polymorphous amorphous-to-quasicrystalline phase transformation in Zr66.7Pd33.3 metallic glass

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Saksl, K.; Saida, J.

    2002-01-01

    The amorphous-to-quasicrystalline phase transformation and the pressure effect on the transformation in a Zr66.7Pd33.3 metallic glass have been investigated by in situ x-ray diffraction measurements using synchrotron radiation. It is found that the transformation is a polymorphous reaction...

  2. Change of quasilattice constant during amorphous-to-quasicrystalline phase transformation in Zr65Al7.5Ni10Cu7.5Ag10 metallic glass

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Rasmussen, A.R.; Jensen, C.H.

    2002-01-01

    The amorphous-to-quasicrystalline phase transformation in a Zr65Al7.5Ni10Cu7.5Ag10 metallic glass has been investigated by monitoring the quasilattice constant and the composition of quasicrystalline particles in the samples annealed in vacuum at 663 K for various times. It is found that the quas......The amorphous-to-quasicrystalline phase transformation in a Zr65Al7.5Ni10Cu7.5Ag10 metallic glass has been investigated by monitoring the quasilattice constant and the composition of quasicrystalline particles in the samples annealed in vacuum at 663 K for various times. It is found......Cu7.5Ag10 metallic glass is a nonpolymorphous reaction....

  3. Assessment of phase constitution on the Al-rich region of rapidly solidified Al-Co-Fe-Cr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, W., E-mail: witorw@gmail.com [Programa de Pós-Graduação em Ciência e Engenharia de Materiais, Universidade Federal de São Carlos, Rod. Washington Luiz, Km 235, 13565-905 São Carlos, SP (Brazil); Bolfarini, C., E-mail: cbolfa@ufscar.br [Departamento de Engenharia de Materiais, Universidade Federal de São Carlos, Rod. Washington Luiz, Km 235, 13565-905 São Carlos, SP (Brazil); Kiminami, C.S., E-mail: kiminami@ufscar.br [Departamento de Engenharia de Materiais, Universidade Federal de São Carlos, Rod. Washington Luiz, Km 235, 13565-905 São Carlos, SP (Brazil); Botta, W.J., E-mail: wjbotta@ufscar.br [Departamento de Engenharia de Materiais, Universidade Federal de São Carlos, Rod. Washington Luiz, Km 235, 13565-905 São Carlos, SP (Brazil)

    2016-12-15

    The formation of quasicrystalline approximants in rapidly solidified Al-Co-Fe-Cr alloys was investigated. Alloys of atomic composition Al{sub 71}Co{sub 13}Fe{sub 8}Cr{sub 8}, Al{sub 77}Co{sub 11}Fe{sub 6}Cr{sub 6} and Al{sub 76}Co{sub 19}Fe{sub 4}Cr{sub 1} were produced using melt spinning and arc melting methods and their microstructural characterization was carried out by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Up to the present there is no consensus in the literature regarding the formation of quasicrystalline phase or quasicrystalline approximants in the Al{sub 71}Co{sub 13}Fe{sub 8}Cr{sub 8} alloy. This work presents, for the first time, a detailed structural characterization of selected alloys in the Al-Co-Fe-Cr system close to the atomic composition Al{sub 71}Co{sub 13}Fe{sub 8}Cr{sub 8}. The results indicated the samples to be composed, mostly, by two intermetallic phases, which are quaternary extensions of Al{sub 5}Co{sub 2} and Al{sub 13}Co{sub 4} and are quasicrystalline approximants. Although the Al{sub 5}Co{sub 2} phase has already been reported in the Al{sub 71}Co{sub 13}Fe{sub 8}Cr{sub 8} alloy, the presence of the monoclinic Al{sub 13}Co{sub 4} is now identified for the first time in the as cast state. In the binary Al-Co system a quasicrystalline phase is known to form in a rapidly solidified alloy with composition close to the monoclinic and orthorhombic Al{sub 13}Co{sub 4} phases. This binary quasicrystalline phase presents an average valence electron per atom (e/a) between 1.7 and 1.9; thus, in addition to the Al{sub 71}Co{sub 13}Fe{sub 8}Cr{sub 8} alloy, the compositions Al{sub 77}Co{sub 11}Fe{sub 6}Cr{sub 6} and Al{sub 76}Co{sub 19}Fe{sub 4}Cr{sub 1} were chosen to be within the region of formation of the quaternary extension of the Al{sub 13}Co{sub 4} phase and also within the (e/a) of 1.7 to 1.9. However, no quasicrystalline phase is present in any of the studied alloys. The Al-Co-Fe-Cr system

  4. Assessment of phase constitution on the Al-rich region of rapidly solidified Al-Co-Fe-Cr alloys

    International Nuclear Information System (INIS)

    Wolf, W.; Bolfarini, C.; Kiminami, C.S.; Botta, W.J.

    2016-01-01

    The formation of quasicrystalline approximants in rapidly solidified Al-Co-Fe-Cr alloys was investigated. Alloys of atomic composition Al 71 Co 13 Fe 8 Cr 8 , Al 77 Co 11 Fe 6 Cr 6 and Al 76 Co 19 Fe 4 Cr 1 were produced using melt spinning and arc melting methods and their microstructural characterization was carried out by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Up to the present there is no consensus in the literature regarding the formation of quasicrystalline phase or quasicrystalline approximants in the Al 71 Co 13 Fe 8 Cr 8 alloy. This work presents, for the first time, a detailed structural characterization of selected alloys in the Al-Co-Fe-Cr system close to the atomic composition Al 71 Co 13 Fe 8 Cr 8 . The results indicated the samples to be composed, mostly, by two intermetallic phases, which are quaternary extensions of Al 5 Co 2 and Al 13 Co 4 and are quasicrystalline approximants. Although the Al 5 Co 2 phase has already been reported in the Al 71 Co 13 Fe 8 Cr 8 alloy, the presence of the monoclinic Al 13 Co 4 is now identified for the first time in the as cast state. In the binary Al-Co system a quasicrystalline phase is known to form in a rapidly solidified alloy with composition close to the monoclinic and orthorhombic Al 13 Co 4 phases. This binary quasicrystalline phase presents an average valence electron per atom (e/a) between 1.7 and 1.9; thus, in addition to the Al 71 Co 13 Fe 8 Cr 8 alloy, the compositions Al 77 Co 11 Fe 6 Cr 6 and Al 76 Co 19 Fe 4 Cr 1 were chosen to be within the region of formation of the quaternary extension of the Al 13 Co 4 phase and also within the (e/a) of 1.7 to 1.9. However, no quasicrystalline phase is present in any of the studied alloys. The Al-Co-Fe-Cr system, around the compositions studied, is composed of quaternary extensions of Al-Co intermetallic phases, which present solubility of Fe and Cr at Co atomic sites. - Highlights: •The Al rich region of the Al

  5. Microstructure and heat resistance of Mg-Al-Zn alloys containing metastable phase

    International Nuclear Information System (INIS)

    Kim, Jeong-Min; Park, Bong-Koo; Jun, Joong-Hwan; Shin, Keesam; Kim, Ki-Tae; Jung, Woon-Jae

    2007-01-01

    In this research microstructural studies have been made on cast specimens of AZ91 base alloys containing various amounts of Zn. As the amount of Zn addition increased up to 2%, any new Zn-containing phase did not appear while the Zn content in Mg 17 Al 12 phase continuously increased. A quasi-crystalline phase started to form at Mg 17 Al 12 phase when the added Zn content was about 3 wt.%. The tensile strength and elongation of the alloys at 175 deg. C were observed to increase significantly with increasing Zn content. The quasi-crystalline phase was found to be stable up to 300 deg. C, based on scanning electron microscopy examinations of the specimens heated at different temperatures for 24 h

  6. Solid and liquid thermal expansion and structural observations in the quasicrystalline Cd84Yb16 compound

    International Nuclear Information System (INIS)

    Kramer, M.J.; Lograsso, T.A.; Sordelet, D.J.

    2010-01-01

    The structure of single-grain Cd 84 Yb 16 samples aligned along the twofold and fivefold axes has been followed from 300 to 1050 K using high-energy synchrotron X-rays. The quasicrystal phase is stable up to its melting temperature of 914 K and has a large linear thermal expansion of 37.1 ppm K -1 over this temperature range. The samples melt congruently over a temperature range of less than 1 K. The liquid is 7% less dense than the solid and, upon cooling from the melt, the quasicrystal phase directly solidifies within a 1 K interval. The amount of undercooling achieved, about 5-25 K, was dependent on the cooling rate. The total scattering function of the liquid is consistent with a dilute liquid Cd structure. These results agree with suggestions that the structure of the liquid must undergo reordering in order to form the solid phases. However, there is no compelling evidence for icosahedral short-range order in the liquid prior to the formation of the quasicrystalline structure.

  7. Microstructure engineering of TiAl-based refractory intermetallics within power-down directional solidification process

    International Nuclear Information System (INIS)

    Kartavykh, A.V.; Tcherdyntsev, V.V.; Gorshenkov, M.V.; Kaloshkin, S.D.

    2014-01-01

    Highlights: ► VGF power-down technique is suitable for TiAl-based alloys solidification with tailored microstructure. ► Both columnar-dendrite and granular structures are created in Ti–46Al–8Nb ingots. ► Granular microstructure has been refined with TiB 2 addition to the melt. ► TiB 2 re-precipitate into (Ti,Nb)B particles, those acting as point seeds for fine equiaxed grains nucleation. -- Abstract: The work is aimed at the study of the formation and refinement of primary microstructure appearing in the refractory lightweight structural TiAl-based alloy of Ti–46Al–8Nb (at.%) nominal composition. For tailored microstructure development, the Directional Solidification (DS) of pre-synthesized alloy was performed in the vertical multizone resistive electro-furnace by power-down technique in pure argon environment. Both columnar-dendrite, and equiaxed-granular reproducible as-cast microstructures have been produced in DS ingots, basing on Columnar-to-Equiaxed Transition (CET) diagram and experimental exploration. Particular attention was paid further to equiaxed microstructure improvement by combination of modifying doping of alloy with boron grain refiner and DS processing. As a result the perfect inoculated microstructure of Ti–44Al–7Nb–2B (at.%) ingots was produced with 100 μm mean grain diameter, low scattering of dimensional grain characteristics and high tolerance to DS process parameters variation

  8. High temperature cyclic oxidation of Ti-Al based intermetallic in static laboratory air

    International Nuclear Information System (INIS)

    Astuty Amrin; Esah Hamzah; Nurfashahidayu Mohd Badri; Hafida Hamzah

    2007-01-01

    The objective of this study is to investigate the oxidation behaviour of binary γ-Ti Al based intermetallics with composition (at%) of 45A, 48Al and 50 Al, and ternary alloys of Ti-48Al containing 2Cr and 4Cr. Thermal cyclic oxidation was conducted discontinuously at temperatures of 700 degree Celsius and 900 degree Celsius in static laboratory air. Optical microscopy, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDX) and X-ray diffraction (XRD) techniques were employed for the analysis. SEM examination of cross-sectional samples using secondary electron and line-scan analysis after exposure at 700 degree Celsius showed that non-adherent oxides scales formed due to the spallation caused by cyclic condition. For exposure to 900 degree Celsius, only binary alloys exhibited breakaway oxidation whereas the oxide scales formed on the ternary alloys were well-adhered on the substrate alloy. Overall, exposure at 900 degree Celsius resulted in thicker and harder oxide scales and addition of Cr seems to improve oxidation resistance of Ti-Al based intermetallics at higher temperature. (author)

  9. Casting of particulate Al-base composites

    International Nuclear Information System (INIS)

    Moustafa, S.F.

    1997-01-01

    A molten Al-4 wt.% Cu as well as a Al-13 wt.% Si alloy have been mixed mechanically with particulate of SiC, Al 2 O 3 , or graphite. After the completion of mixing, each mixture was poured into a permanent mould to solidify. To overcome the problem of non-wettability that exists between the investigated particulate and the molten aluminum alloys the particulate was chemically treated by impregnation in a solution containing Na + ions. The loading of SiC or Al 2 O 3 particulate in the produced composites can be as high as 40 wt.%, and for graphite particles it can be 20 wt.%. The mixing time required to introduce and distribute the investigated particles into the molten matrix was as low as five minutes to recluce chemical reactions at the interfaces between them. Processing details and parameters controlling this technique are described. Metallographic examinations as well as tensile tests were carried out to characterize the microstructure, the distribution of the particles and the strength of these composites. The results display that the composites made by this technique have good microstructure and tensile properties. (orig.)

  10. Applications of Ni3Al Based Intermetallic Alloys—Current Stage and Potential Perceptivities

    Directory of Open Access Journals (Sweden)

    Pawel Jozwik

    2015-05-01

    Full Text Available The paper presents an overview of current and prospective applications of Ni3Al based intermetallic alloys—modern engineering materials with special properties that are potentially useful for both structural and functional purposes. The bulk components manufactured from these materials are intended mainly for forging dies, furnace assembly, turbocharger components, valves, and piston head of internal combustion engines. The Ni3Al based alloys produced by a directional solidification are also considered as a material for the fabrication of jet engine turbine blades. Moreover, development of composite materials with Ni3Al based alloys as a matrix hardened by, e.g., TiC, ZrO2, WC, SiC and graphene, is also reported. Due to special physical and chemical properties; it is expected that these materials in the form of thin foils and strips should make a significant contribution to the production of high tech devices, e.g., Micro Electro-Mechanical Systems (MEMS or Microtechnology-based Energy and Chemical Systems (MECS; as well as heat exchangers; microreactors; micro-actuators; components of combustion chambers and gasket of rocket and jet engines as well components of high specific strength systems. Additionally, their catalytic properties may find an application in catalytic converters, air purification systems from chemical and biological toxic agents or in a hydrogen “production” by a decomposition of hydrocarbons.

  11. Quasicrystalline and crystalline precipitation during isothermal tempering in a 12Cr-9Ni-4Mo maraging stainless steel

    International Nuclear Information System (INIS)

    Liu, P.; Stigenberg, A.H.; Nilsson, J.O.

    1995-01-01

    A thorough microstructural investigation has been performed on a high strength maraging steel of the type 12%Cr-9%Ni-4%Mo-2%Cu-1%Ti. The major precipitate formed during isothermal aging at 475 C is a quasicrystalline phase possessing icosahedral symmetry termed R'-phase with a typical chemical composition of 48%Mo-33%Fe-13%Cr-2%Ni-4%Si. At 550 C the major precipitate is trigonal R-phase with a typical composition of 45%Mo-31%Fe-18%Cr-4%Ni-2%Si. At 550 C also Laves phase with a composition of 48%Mo-35%Fe-13%Cr-2%Ni-2%Si could be observed. At both 475 and 550 C an ordered phase termed L-phase precipitated. This minority phase has an ordered face centered cubic (f.c.c.) structure of type L1 0 . Its composition is typically 9%Fe-4%Cr-52%Ni-15%Mo.-16%Ti-4%Al. R'-phase formed at 475 C transformed to R-phase and Laves phase during aging at 550 C. In an analogous manner, R-phase and Laves phase formed at 550 C transformed to R'-phase during subsequent aging at 475 C. This transformation was rationalized by a strong similarity in crystal structure between quasicrystalline R'-phase of icosahedral symmetry and Frank-Kasper phases such as R-phase and Laves phase

  12. Structure and Mechanical Properties of Al-Cu-Fe-X Alloys with Excellent Thermal Stability

    Directory of Open Access Journals (Sweden)

    Andrea Školáková

    2017-11-01

    Full Text Available In this work, the structure and mechanical properties of innovative Al-Cu-Fe based alloys were studied. We focused on preparation and characterization of rapidly solidified and hot extruded Al-Cu-Fe, Al-Cu-Fe-Ni and Al-Cu-Fe-Cr alloys. The content of transition metals affects mechanical properties and structure. For this reason, microstructure, phase composition, hardness and thermal stability have been investigated in this study. The results showed exceptional thermal stability of these alloys and very good values of mechanical properties. Alloying by chromium ensured the highest thermal stability, while nickel addition refined the structure of the consolidated alloy. High thermal stability of all tested alloys was described in context with the transformation of the quasicrystalline phases to other types of intermetallics.

  13. Structure and Mechanical Properties of Al-Cu-Fe-X Alloys with Excellent Thermal Stability.

    Science.gov (United States)

    Školáková, Andrea; Novák, Pavel; Mejzlíková, Lucie; Průša, Filip; Salvetr, Pavel; Vojtěch, Dalibor

    2017-11-05

    In this work, the structure and mechanical properties of innovative Al-Cu-Fe based alloys were studied. We focused on preparation and characterization of rapidly solidified and hot extruded Al-Cu-Fe, Al-Cu-Fe-Ni and Al-Cu-Fe-Cr alloys. The content of transition metals affects mechanical properties and structure. For this reason, microstructure, phase composition, hardness and thermal stability have been investigated in this study. The results showed exceptional thermal stability of these alloys and very good values of mechanical properties. Alloying by chromium ensured the highest thermal stability, while nickel addition refined the structure of the consolidated alloy. High thermal stability of all tested alloys was described in context with the transformation of the quasicrystalline phases to other types of intermetallics.

  14. Processing and Characterization of Mechanically Alloyed NiAl-Based Alloys

    Science.gov (United States)

    1994-07-20

    The ductility of the .MA material decreases at 800 K arranged in networks but many single dislocations are and again increases at higher temperatures...dislocation density increases significantly compared to the hot extruded material. Dislocations are often arranged in a network but many single...P. Deiavigette and S. Amelinckx, Phil. Mag., 5, 729 (1960). 10. K. Vedula and P.S. Khadkikar, High Te= nerone Ahi kides anwd Inmerti s, p.197, S.H

  15. Formation of quasicrystals and amorphous-to-quasicrystalline phase transformation kinetics in Zr65Al7.5Ni10Cu7.5Ag10 metallic glass under pressure

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Zhuang, Yanxin; Rasmussen, Helge Kildahl

    2001-01-01

    The effect of pressure on the formation of quasicrystals and the amorphous-to-quasicrystalline phase transformation kinetics in the supercooled liquid region for a Zr65Al7.5Ni10Cu7.5Ag10 metallic glass have been investigated by in situ high-pressure and high-temperature nonisothermal and isothermal...... of quasicrystals decrease, Atomic mobility is important for the formation of quasicrystals from the metallic glass whereas the relationship of the crystallization temperature vs pressure for the transition from the quasicrystalline state to intermetallic compounds may mainly depend on the thermodynamic potential...... energy barrier. To study the amorphous-to-quasicrystalline phase transformation kinetics in the metallic glass, relative volume fractions of the transferred quasicrystalline phase as a function of annealing time, obtained at 663, 673, 683, and 693 K, have been analyzed in details using 14 nucleation...

  16. Salt fog corrosion behavior in a powder-processed icosahedral-phase-strengthened aluminum alloy

    International Nuclear Information System (INIS)

    Watson, T.J.; Gordillo, M.A.; Ernst, A.T.; Bedard, B.A.; Aindow, M.

    2017-01-01

    Highlights: • Pitting corrosion resistance has been evaluated for an Al-Cr-Mn-Co-Zr alloy. • Pit densities and depths are far lower than for other high-strength Al alloys. • Corrosion proceeds by selective oxidation of the Al matrix around the other phases. - Abstract: The pitting corrosion resistance has been evaluated for a powder-processed Al-Cr-Mn-Co-Zr alloy which contains ≈35% by volume of an icosahedral quasi-crystalline phase and a little Al 9 Co 2 in an Al matrix. ASTM standard salt fog exposure tests show that the alloy exhibits far lower corrosion pit densities and depths than commercial high-strength aerospace Al alloys under the same conditions. Electron microscopy data show that the salt fog exposure leads to the selective oxidation of the face-centered cubic Al matrix around the other phases, and to the development of a porous outer oxide scale.

  17. Effect of processing on the microstructural development in a rapidly solidified Al-Fe-V-Si alloy

    International Nuclear Information System (INIS)

    Srivastava, A.K.; Ranganathan, S.; Ojha, S.N.

    1993-01-01

    An Al 80 Fe 10 Si 6 alloy has been rapidly solidified using melt spinning, gas atomization and spray forming processes. The effect of processing techniques on the microstructural characteristics of the alloy has ben evaluated. The melt spun alloy has shown an icosahedral quasicrystalline phase surrounded by a rational approximant structure of the icosahedral phase. The rational approximant structure has been identified as a crystalline cubic silicide phase. The atomized powders have exhibited cellular and dendritic morphology depending on the size of particles. In addition, the second phase particles of the silicide phase are observed to decorate the cell boundaries and interdendritic regions. In contrast, the alloy processed by spray deposition has revealed an equiaxed solidification morphology with a uniform dispersion of find silicon phase inside the grain. The origin of the microstructure in the alloy processed by these techniques is discussed. The results are compared wherever possible with the commercially available Al-Fe-V-Si alloys

  18. Lanthanum hexaboride as advanced structural refiner/getter in TiAl-based refractory intermetallics

    Energy Technology Data Exchange (ETDEWEB)

    Kartavykh, A.V., E-mail: karta@korolev-net.ru [Technological Institute for Superhard and Novel Carbon Materials (TISNCM), 7a Centralnaya str., 142190 Troitsk, Moscow (Russian Federation); National University of Science and Technology “MISIS”, Leninsky pr. 4, 119049 Moscow (Russian Federation); Asnis, E.A.; Piskun, N.V.; Statkevich, I.I. [The E.O. Paton Electric Welding Institute, 11 Bozhenko str., 03680 Kyiv (Ukraine); Gorshenkov, M.V.; Tcherdyntsev, V.V. [National University of Science and Technology “MISIS”, Leninsky pr. 4, 119049 Moscow (Russian Federation)

    2014-03-05

    Highlights: • Fist application of LaB{sub 6} additive in TiAl-based intermetallics casting. • Pilot synthesis/casting and study of selected TiAl(Nb,Cr,Zr)B,La alloys set. • Dual effect observed: phase structure refinement and oxygen impurity removal. • Co-precipitation of TiB and La{sub 2}O{sub 3} in melt: 2LaB{sub 6} + 12Ti + 3O → 12TiB↓ + La{sub 2}O{sub 3}↓. • Features of structure refinement and oxygen gettering mechanisms reported. -- Abstract: The work is aimed at the study of the formation and refinement of microstructure appearing in the solidifying refractory TiAl-based intermetallics being inoculated with precise boron addition. The novelty of research consists in test application of lanthanum hexaboride (LaB{sub 6}) ligature within semi-continuous electron beam casting process of selected alloys. Two ingots with nominal compositions Ti–44Al–5Nb–2Cr–1.5Zr–0.4B–0.07La and Ti–44Al–5Nb–1Cr–1.5Zr–1B–0.17La (at.%) have been synthesized and cast along with the reference alloy Ti–44Al–5Nb–3Cr–1.5Zr. Their comparative examination suggests (i) essential microstructural phase refinement effect coupled with (ii) threefold/fourfold decrease of background content of undesirable residual oxygen impurity in both alloys containing LaB{sub 6}. This advanced dual activity (i–ii) of LaB{sub 6} is explained by its complete dissolution, dissociation and following re-precipitation of effective Ti-based monoboride nucleants of orthorhombic B27 structure, those being accompanied by strong internal gettering of dissolved oxygen from the melt and from boride-inoculated solid α{sub 2}-Ti{sub 3}Al phase with liberated elemental lanthanum. The phase composition and structure of cast alloys; state and characterization of newly precipitated TiB boride; features of La{sub 2}O{sub 3} micro/nano-dimensional precipitation and oxygen gettering mechanism are reported and discussed.

  19. Advanced ordered intermetallic alloy deployment

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-04-01

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

  20. The formation of quasicrystal phase in Al-Cu-Fe system by mechanical alloying

    OpenAIRE

    Travessa, Dilermando Nagle; Cardoso, Kátia Regina; Wolf, Witor; Jorge Junior, Alberto Moreira; Botta, Walter José

    2012-01-01

    In order to obtain quasicrystalline (QC) phase by mechanical alloying (MA) in the Al-Cu-Fe system, mixtures of elementary Al, Cu and Fe in the proportion of 65-20-15 (at. %) were produced by high energy ball milling (HEBM). A very high energy type mill (spex) and short milling times (up to 5 hours) were employed. The resulting powders were characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). QC phase was not directly formed ...

  1. Magnesium secondary alloys: Alloy design for magnesium alloys with improved tolerance limits against impurities

    Energy Technology Data Exchange (ETDEWEB)

    Blawert, C., E-mail: carsten.blawert@gkss.d [GKSS Forschungszentrum Geesthacht GmbH, Max-Planck-Str. 1, 21502 Geesthacht (Germany); Fechner, D.; Hoeche, D.; Heitmann, V.; Dietzel, W.; Kainer, K.U. [GKSS Forschungszentrum Geesthacht GmbH, Max-Planck-Str. 1, 21502 Geesthacht (Germany); Zivanovic, P.; Scharf, C.; Ditze, A.; Groebner, J.; Schmid-Fetzer, R. [TU Clausthal, Institut fuer Metallurgie, Robert-Koch-Str. 42, 38678 Clausthal-Zellerfeld (Germany)

    2010-07-15

    The development of secondary magnesium alloys requires a completely different concept compared with standard alloys which obtain their corrosion resistance by reducing the levels of impurities below certain alloy and process depending limits. The present approach suitable for Mg-Al based cast and wrought alloys uses a new concept replacing the {beta}-phase by {tau}-phase, which is able to incorporate more impurities while being electro-chemically less detrimental to the matrix. The overall experimental effort correlating composition, microstructure and corrosion resistance was reduced by using thermodynamic calculations to optimise the alloy composition. The outcome is a new, more impurity tolerant alloy class with a composition between the standard AZ and ZC systems having sufficient ductility and corrosion properties comparable to the high purity standard alloys.

  2. Microstructure and functional properties of the TiNi- and CuAl-based SMA thin films and coats produced by PVD technique

    International Nuclear Information System (INIS)

    Kolomytsev, V.; Musienko, R.; Nevdacha, V.; Panarin, V.; Pasko, A.; Cesari, E.; Segui, C.; Humbeeck, J. van

    2000-01-01

    The TiNi- and CuAl-based shape memory alloy thin films and wear/corrosion resistant surface coats have been produced by the ion-plasma deposition method with an arc dispersion of the cathode/target. This technique was widely used for production of the coats from a sprayed pure metal or a single-phase alloy. We have offered to use this process for dispersion of the heterophase alloys like shape memory alloys. The arguments for choosing of this technique are discussed with respect to creation of the conditions for preservation not only chemical composition, but also phase structure of an alloy in a covering, thus the shape memory/superelastic effects to be kept in a coat. (orig.)

  3. Method of processing titanium aluminium alloys modified by chromium and niobium

    International Nuclear Information System (INIS)

    Huang, S.C.

    1991-01-01

    This patent describes the method of processing a TiAl base alloy to impart desirable strength and ductility properties which providing a melt of the TiAl base alloy having the formula Ti 51-42 Al 46-50 Cr 1-3 Nb 1-5

  4. Precipitation in an Al–Mg–Cu alloy and the effect of a low amount of Ag

    Energy Technology Data Exchange (ETDEWEB)

    Mihara, Mami, E-mail: mihara.m.aa@m.titech.ac.jp [Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, Tokyo 152-8552 (Japan); Marioara, Calin D., E-mail: Calin.D.Marioara@sintef.no [SINTEF Materials and Chemistry, N-7465 Trondheim (Norway); Andersen, Sigmund J., E-mail: Sigmund.J.Andersen@sintef.no [SINTEF Materials and Chemistry, N-7465 Trondheim (Norway); Holmestad, Randi, E-mail: randi.holmestad@ntnu.no [Faculty of Physics, Norwegian University of Science and Technology, N-7491 Trondheim (Norway); Kobayashi, Equo, E-mail: equo@mtl.titech.ac.jp [Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, Tokyo 152-8552 (Japan); Sato, Tatsuo, E-mail: sato.tatsuo8@gmail.com [Precision and Intelligence Laboratory, Tokyo Institute of Technology, Yokohama 226-8503 (Japan)

    2016-03-21

    Two high-purity aluminium alloys based on composition Al–3.0Mg–1.0Cu (wt%), one with added 0.4 wt% Ag, were compared up to 11 days ageing at 443 K by means of transmission electron microscopy and hardness measurements. The base alloy exhibits an inhomogeneous precipitate microstructure with a high density of fine needle-shaped Guinier-Preston-Bagaryatsky (GPB) zones together with coarser precipitates of S′-Al{sub 2}CuMg and rods of the structurally unknown Z-phase. The S′ phase is preferably formed on dislocations. The addition of Ag has a strong effect, leading to a homogeneous distribution with fine Ag-containing icosahedral quasi-crystalline precipitates (iQC). Both the GPB zones in the base alloy and the iQC phase in the Ag added alloy survive even after long term ageing. Ag is found to suppress the formation of the S′ phase. It is suggested that the Z phase is an approximation phase to the quasi-crystalline phase as is the case for the T-phase, implying they are based on similar (Bergman) clusters.

  5. Physical behaviors of impure atoms during relaxation of impure NiAl-based alloy grain boundary

    International Nuclear Information System (INIS)

    Zheng Liping; Jiang Bingyao; Liu Xianghuai; Li Douxing

    2003-01-01

    The Monte Carlo simulation with the energetics described by the embedded atom method has been employed to mainly study physical behaviors of boron atoms during relaxation of the Ni 3 Al-x at.% B grain boundary. During relaxation of impure Ni 3 Al grain boundaries, authors suggest that for different types of impure atoms (Mg, B, Cr and Zr atoms etc.), as the segregating species, they have the different behaviors, but as the inducing species, they have the same behaviors, i.e. they all induce Ni atoms to substitute Al atoms. Calculations show that at the equilibrium, when x(the B bulk concentration) increases from 0.1 to 0.9, the peak concentration of B increases, correspondently, the peak concentration of Ni maximizes but the valley concentration of Al minimizes, at x=0.5. The calculations also show the approximate saturation of Ni at the grain boundary at x=0.5

  6. Creep of Fe3Al-based alloys with vanadium and carbon additions

    Czech Academy of Sciences Publication Activity Database

    Dobeš, Ferdinand; Pešička, J.; Kratochvíl, P.

    2016-01-01

    Roč. 74, JUL (2016), s. 60-64 ISSN 0966-9795 R&D Projects: GA ČR(CZ) GAP108/12/1452 Institutional support: RVO:68081723 Keywords : Intermetallics (aluminides) * Creep * Microstructure Subject RIV: JG - Metallurgy Impact factor: 3.140, year: 2016

  7. Microstructure and mechanical properties of a Mg–Zn–Y alloy produced by a powder metallurgy route

    Energy Technology Data Exchange (ETDEWEB)

    Asgharzadeh, H. [Department of Materials Engineering, Faculty of Mechanical Engineering, University of Tabriz, P.O. Box 51666-16471, Tabriz (Iran, Islamic Republic of); Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Yoon, E.Y. [Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Chae, H.J.; Kim, T.S. [Korea Institute for Rare Metals, Korea Institute of Industrial Technology, Incheon 406-840 (Korea, Republic of); Lee, J.W. [Korea Institute of Materials Science (KIMS), Changwon 641-831 (Korea, Republic of); Kim, H.S., E-mail: hskim@postech.ac.kr [Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)

    2014-02-15

    In this paper, a bulk Mg–Zn–Y alloy reinforced by quasicrystalline particles was produced by hot extrusion of rapidly-solidified powders. MgZn{sub 4.3}Y{sub 0.7} powders with different particle sizes were prepared by an inert gas atomizer and then extruded at 380 °C with extrusion ratios of 10:1, 15:1, and 20:1. Microstructural studies were performed using an optical microscope, scanning electron microscope, transmission electron microscope, and X-ray diffraction. The mechanical strength and hardness of the extruded materials were enhanced by employing finer Mg alloy powders. More uniform deformation of powders in extruded billets with good tensile properties was achieved at higher extrusion ratios, especially for finer powders. The high strength of the MgZn{sub 4.3}Y{sub 0.7} alloy was preserved at elevated temperatures due to the presence of icosahedral phase nanoparticles.

  8. Fabrication and structure of bulk nanocrystalline Al-Si-Ni-mishmetal alloys

    International Nuclear Information System (INIS)

    Latuch, Jerzy; Cieslak, Grzegorz; Kulik, Tadeusz

    2007-01-01

    Al-based alloys of structure consisting of nanosized Al crystals, embedded in an amorphous matrix, are interesting for their excellent mechanical properties, exceeding those of the commercial crystalline Al-based alloys. Recently discovered nanocrystalline Al alloys containing silicon (Si), rare earth metal (RE) and late transition metal (Ni), combine high tensile strength and good wear resistance. The aim of this work was to manufacture bulk nanocrystalline alloys from Al-Si-Ni-mishmetal (Mm) system. Bulk nanostructured Al 91-x Si x Ni 7 Mm 2 (x = 10, 11.6, 13 at.%) alloys were produced by ball milling of nanocrystalline ribbons followed by high pressure hot isostating compaction

  9. Milling of Nanoparticles Reinforced Al-Based Metal Matrix Composites

    Directory of Open Access Journals (Sweden)

    Alokesh Pramanik

    2018-03-01

    Full Text Available This study investigated the face milling of nanoparticles reinforced Al-based metal matrix composites (nano-MMCs using a single insert milling tool. The effects of feed and speed on machined surfaces in terms of surface roughness, surface profile, surface appearance, chip surface, chip ratio, machining forces, and force signals were analyzed. It was found that surface roughness of machined surfaces increased with the increase of feed up to the speed of 60 mm/min. However, at the higher speed (100–140 mm/min, the variation of surface roughness was minor with the increase of feed. The machined surfaces contained the marks of cutting tools, lobes of material flow in layers, pits and craters. The chip ratio increased with the increase of feed at all speeds. The top chip surfaces were full of wrinkles in all cases, though the bottom surfaces carried the evidence of friction, adhesion, and deformed material layers. The effect of feed on machining forces was evident at all speeds. The machining speed was found not to affect machining forces noticeably at a lower feed, but those decreased with the increase of speed for the high feed scenario.

  10. Application of mechanical alloying to synthesis of intermetallic phases based alloys

    International Nuclear Information System (INIS)

    Dymek, S.

    2001-01-01

    Mechanical alloying is the process of synthesis of powder materials during milling in high energetic mills, usually ball mills. The central event in mechanical alloying is the ball-powder-ball collision. Powder particles are trapped between the colliding balls during milling and undergo deformation and/or fracture. Fractured parts are cold welded. The continued fracture and cold welding results in a uniform size and chemical composition of powder particles. The main applications of mechanical alloying are: processing of ODS alloys, syntheses of intermetallic phases, synthesis of nonequilibrium structures (amorphous alloys, extended solid solutions, nanocrystalline, quasi crystals) and magnetic materials. The present paper deals with application of mechanical alloying to synthesis Ni A l base intermetallic phases as well as phases from the Nb-Al binary system. The alloy were processed from elemental powders. The course of milling was monitored by scanning electron microscopy and X-ray diffraction. After milling, the collected powders were sieved by 45 μm grid and hot pressed (Nb alloys and NiAl) or hot extruded (NiAl). The resulting material was fully dense and exhibited fine grain (< 1 μm) and uniform distribution of oxide dispersoid. The consolidated material was compression and creep tested. The mechanical properties of mechanically alloys were superior to properties of their cast counterparts both in the room and elevated temperatures. Higher strength of mechanically alloyed materials results from their fine grains and from the presence of dispersoid. At elevated temperatures, the Nb-Al alloys have higher compression strength than NiAl-based alloys processed at the same conditions. The minimum creep rates of mechanically alloyed Nb alloys are an order of magnitude lower than analogously processed NiAl-base alloys. (author)

  11. Processing and Mechanical Properties of NiAl-Based In-Situ Composites. Ph.D. Thesis Final Report

    Science.gov (United States)

    Johnson, David Ray

    1994-01-01

    In-situ composites based on the NiAl-Cr eutectic system were successfully produced by containerless processing and evaluated. The NiAl-Cr alloys had a fibrous microstructure while the NiAl-(Cr,Mo) alloys containing 1 at. percent or more molybdenum exhibited a lamellar structure. The NiAl-28Cr-6Mo eutectic displays promising high temperature strength while still maintaining a reasonable room temperature fracture toughness when compared to other NiAl-based materials. The Laves phase NiAlTa was used to strengthen NiAl and very promising creep strengths were found for the directionally solidified NiAl-NiAlTa eutectic. The eutectic composition was found to be near NiAl-15.5Ta (at. percent) and well aligned microstructures were produced at this composition. An off-eutectic composition of NiAl-14.5Ta was also processed, consisting of NiAl dendrites surrounded by aligned eutectic regions. The room temperature toughness of these two phase alloys was similar to that of polycrystalline NiAl even with the presence of the brittle Laves phase NiAlTa. Polyphase in-situ composites were generated by directional solidification of ternary eutectics. The systems investigated were the Ni-Al-Ta-X (X=Cr, Mo, or V) alloys. Ternary eutectics were found in each of these systems and both the eutectic composition and temperature were determined. Of these ternary eutectics, the one in the NiAl-Ta-Cr system was found to be the most promising. The fracture toughness of the NiAl-(Cr,Al)NiTa-Cr eutectic was intermediate between those of the NiAl-NiAlTa eutectic and the NiAl-Cr eutectic. The creep strength of this ternary eutectic was similar to or greater than that of the NiAl-Cr eutectic.

  12. Fabrication and mechanical properties of quasicrystal-reinforced Al-Mn-Mm alloys

    International Nuclear Information System (INIS)

    Jun, Joong-Hwan; Kim, Jeong-Min; Kim, Ki-Tae; Jung, Woon-Jae

    2007-01-01

    Microstructures and room temperature mechanical properties of quasicrystal-reinforced Al 94-x Mn 6 Mm x (Mm: misch metal, x = 0-6 at.%) alloys have been studied systematically. Cylindrical rod samples with 3 mm in diameter were synthesized by injection-casting into a Cu mould and analyzed by means of X-ray diffractometry, differential scanning calorimetry, optical microscopy and scanning electron microscopy with energy-dispersive X-ray spectrometry. Mechanical properties of the cylindrical rods were measured at room temperature by compression tests. The Al 94 Mn 6 alloy contains hexagonal-shape particles and long needle-shape Al 6 Mn precipitates surrounded by α-Al matrix. An addition of Mm into the Al 94 Mn 6 alloy generates icosahedral quasicrystalline phase (IQC) with an extinction of hexagonal and Al 6 Mn phases, and the fraction of IQC increases continuously with an increase in Mm content. Compressive yield strength (σ cys ) and ultimate compressive strength (σ ucs ) of the Al-Mn-Mm alloys are improved with Mm content up to 4%, whereas elongation is steeply deteriorated by the Mm addition. The Al 90 Mn 6 Mm 4 alloy exhibits the highest 570 and 783 MPa of σ cys and σ ucs , respectively, both of which are comparable to those of Al 90 Mn 6 Ce 4 alloy

  13. Development and Characterization of Carbon Nanotubes (CNTs) and Silicon Carbide (SiC) Reinforced Al-based Nanocomposites

    Science.gov (United States)

    Gujba, Kachalla Abdullahi

    Composites are engineered materials developed from constituent materials; matrix and reinforcements, to attain synergistic behavior at the micro and macroscopic level which are different from the individual materials. The high specific strength, low weight, excellent chemical resistance and fatigue endurance makes these composites superior than other materials despite anisotropic behaviors. Metal matrix composites (MMCs) have excellent physical and mechanical properties and alumium (Al) alloy composites have gained considerable interest and are used in multiple industries including: aerospace, structural and automotive. The aim of this research work is to develop an advanced Al-based nanocomposites reinforced with Carbon nanotubes (CNTs) and silicon carbide particulates (SiCp) nanophases using mechanical alloying and advanced consolidation procedure (Non-conventional) i.e. Spark Plasma Sintering (SPS) using two types of aluminum alloys (Al-7Si-0.3mg and Al-12Si-0.3Mg). Different concentrations of SiCp and CNTs were added and ball milled for different milling periods under controlled atmosphere to study the effect of milling time and the distribution of the second phases. Characterization techniques were used to investigate the morphology of the as received monolithic and milled powder using Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive Spectroscopy (EDS), X-Ray Mapping, X-Ray Diffraction (XRD) and Particle Size Analyses (PSA). The results revealed that the addition of high concentrations of SiCp and CNTs in both alloys aided in refining the structure of the resulting powder further as the reinforcement particles acted like a grinding agent. Good distribution of reinforcing particles was observed from SEM and no compositional fluctuations were observed from the EDS. Some degree of agglomerations was observed despite the ethyl alcohol sonication effect of the CNTs before ball milling. From the XRD; continuous reduction in crystallite size and

  14. Alloy materials

    Energy Technology Data Exchange (ETDEWEB)

    Hans Thieme, Cornelis Leo (Westborough, MA); Thompson, Elliott D. (Coventry, RI); Fritzemeier, Leslie G. (Acton, MA); Cameron, Robert D. (Franklin, MA); Siegal, Edward J. (Malden, MA)

    2002-01-01

    An alloy that contains at least two metals and can be used as a substrate for a superconductor is disclosed. The alloy can contain an oxide former. The alloy can have a biaxial or cube texture. The substrate can be used in a multilayer superconductor, which can further include one or more buffer layers disposed between the substrate and the superconductor material. The alloys can be made a by process that involves first rolling the alloy then annealing the alloy. A relatively large volume percentage of the alloy can be formed of grains having a biaxial or cube texture.

  15. The formation of quasicrystal phase in Al-Cu-Fe system by mechanical alloying

    Directory of Open Access Journals (Sweden)

    Dilermando Nagle Travessa

    2012-10-01

    Full Text Available In order to obtain quasicrystalline (QC phase by mechanical alloying (MA in the Al-Cu-Fe system, mixtures of elementary Al, Cu and Fe in the proportion of 65-20-15 (at. % were produced by high energy ball milling (HEBM. A very high energy type mill (spex and short milling times (up to 5 hours were employed. The resulting powders were characterized by X-ray diffraction (XRD, differential scanning calorimetry (DSC and scanning electron microscopy (SEM. QC phase was not directly formed by milling under the conditions employed in this work. However, phase transformations identified by DSC analysis reveals that annealing after HEBM possibly results in the formation of the ψ QC phase.

  16. Transformation processes during annealing of Al-amorphous alloys

    International Nuclear Information System (INIS)

    Petrescu, N.; Petrescu, M.; Calin, M.; Jianu, A.D.; Fecioru, M.

    1993-01-01

    As the amorphous aluminum alloys represent the newest achievement in rapid solidification of Al-based high strength heat resistent materials, a study was undertaken on the amorphous alloys in the Al-RE-TM system, the rare-earth metal being a lanthanide mixture and the transition metal a Ni-Fe substitution in definite proportions. The decomposition on heating of the most highly alloyed amorphous alloy in the investigated series is characterized by differential thermal analysis, electron microscopy and X-ray diffraction. (orig.)

  17. Transformation processes during annealing of Al-amorphous alloys

    Energy Technology Data Exchange (ETDEWEB)

    Petrescu, N. (Polytechnic Inst. Bucharest, Faculty Materials Science and Engineering, Bucharest (Romania)); Petrescu, M. (Polytechnic Inst. Bucharest, Faculty Materials Science and Engineering, Bucharest (Romania)); Calin, M. (Polytechnic Inst. Bucharest, Faculty Materials Science and Engineering, Bucharest (Romania)); Jianu, A.D. (Polytechnic Inst. Bucharest, Faculty Materials Science and Engineering, Bucharest (Romania) IFTM-Bucharest (Romania)); Fecioru, M. (Polytechnic Inst. Bucharest, Faculty Materials Science and Engineering, Bucharest (Romania) DACIA Enterprise-Bucharest (Romania))

    1993-11-01

    As the amorphous aluminum alloys represent the newest achievement in rapid solidification of Al-based high strength heat resistent materials, a study was undertaken on the amorphous alloys in the Al-RE-TM system, the rare-earth metal being a lanthanide mixture and the transition metal a Ni-Fe substitution in definite proportions. The decomposition on heating of the most highly alloyed amorphous alloy in the investigated series is characterized by differential thermal analysis, electron microscopy and X-ray diffraction. (orig.).

  18. Impact of beryllium additions on thermal and mechanical properties of conventionally solidified and melt-spun Al–4.5 wt.%Mn–x wt.%Be (x = 0, 1, 3, 5) alloys

    International Nuclear Information System (INIS)

    Öz, Turan; Karaköse, Ercan; Keskin, Mustafa

    2013-01-01

    Highlights: • Thermal and mechanical properties of Al–Mn–Be alloys were investigated. • IQC Al–Mn–Be alloys were synthesized by the CS and MS techniques. • The volume fraction of IQC increases continuously with Be content. • The melting points of the QC i-phase were determined between 652 °C and 675 °C. • The maximum H V and σ values were found to be 124 kg/mm 2 and 458 MPa with the addition of 5% Be. - Abstract: The influence of beryllium (Be) addition on the quasicrystal-forming ability, thermal and mechanical properties of Al–4.5 wt.%Mn–x wt.%Be (x = 0, 1, 3, 5) alloys was investigated in this study. Quasicrystalline Al–Mn–Be alloys were synthesized by the conventionally casting and melt spinning techniques. The microstructures of the samples were characterized by scanning electron microscopy (SEM) and the phase composition was identified by X-ray diffractometry (XRD). The phase transition during the solidification process was studied by differential scanning calorimetry (DSC) and differential thermal analysis (DTA) under an Ar atmosphere. The mechanical properties of the conventionally solidified (CS) and melt-spun (MS) samples were measured by a Vickers micro-hardness indenter and tensile-strength tests. The Al–4.5 wt.%Mn alloy has a hexagonal structure and minor dendritic icosahedral quasicrystalline phase (IQC) precipitates surrounded by an α-Al matrix. Addition of Be into the Al–4.5 wt.%Mn alloy generates intermetallic Be 4 AlMn and IQC phases with the extinction of the hexagonal phase, and the fraction of IQC increases continuously with the increase in Be content. A considerable improvement in microhardness and tensile strength values was observed due to the addition of Be in different percentages into the composition

  19. Quasicrystal-reinforced Mg alloys.

    Science.gov (United States)

    Kyun Kim, Young; Tae Kim, Won; Hyang Kim, Do

    2014-04-01

    The formation of the icosahedral phase (I-phase) as a secondary solidification phase in Mg-Zn-Y and Mg-Zn-Al base systems provides useful advantages in designing high performance wrought magnesium alloys. The strengthening in two-phase composites (I-phase + α -Mg) can be explained by dispersion hardening due to the presence of I-phase particles and by the strong bonding property at the I-phase/matrix interface. The presence of an additional secondary solidification phase can further enhance formability and mechanical properties. In Mg-Zn-Y alloys, the co-presence of I and Ca 2 Mg 6 Zn 3 phases by addition of Ca can significantly enhance formability, while in Mg-Zn-Al alloys, the co-presence of the I-phase and Mg 2 Sn phase leads to the enhancement of mechanical properties. Dynamic and static recrystallization are significantly accelerated by addition of Ca in Mg-Zn-Y alloy, resulting in much smaller grain size and more random texture. The high strength of Mg-Zn-Al-Sn alloys is attributed to the presence of finely distributed Mg 2 Sn and I-phase particles embedded in the α -Mg matrix.

  20. The improvement of technology for high-uranium-density Al-base dispersion fuel plates

    International Nuclear Information System (INIS)

    Shouhui, Dai; Rongxian, Sun; Hejian, Mao; Baosheng, Zhao; Changgen, Yin

    1987-01-01

    An improved rolling process was developed for manufacturing Al-base dispersion fuel plates. When the fuel content in the meat increased up to 50 vol%, the non-uniformity of uranium is not more than ± 7.2%, and the minimum cladding thickness is not less than 0.32 mm. (Author)

  1. Corrosion behaviour and galvanic coupling with steel of Al-based coating alternatives to electroplated cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Fasuba, O.A.; Yerokhin, A., E-mail: A.Yerokhin@sheffield.ac.uk; Matthews, A.; Leyland, A.

    2013-08-15

    The galvanic corrosion behaviour of bare steel coupled to steel with an Al–Zn flake inorganic spin coating, an Al-based slurry sprayed coating, an arc sprayed Al coating and electroplated cadmium has been investigated. The sacrificial and galvanic behaviour of the coatings was studied in 3.5 wt. % NaCl solution using open-circuit potential, potentiodynamic polarisation and electrochemical noise measurements. The coatings were characterised by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. Experimental results showed that the Al-based slurry sprayed coating exhibited an open-circuit potential closer to the steel substrate than other coatings, as well as a low corrosion current density and a more positive corrosion potential. In terms of the galvanic suitability of the investigated coatings for the steel substrate, both the Al–Zn flake inorganic spin coating and the Al-based slurry sprayed coating show low galvanic current, in comparison with the arc sprayed Al coating and electroplated cadmium. This behaviour confirms their superior cathodic protection capability and galvanic compatibility over other coatings tested. Electrochemical noise measurements provide accurate information on the coatings' galvanic behaviour, which can be complimented by the data obtained from superposition of potentiodynamic corrosion scans of the coating and bare steel, provided that the corrosion potential difference between the two materials does not exceed 300 mV. - Highlights: • Al-based slurry coating has best galvanic compatibility with steel. • Mg, Cr, P in Al-based slurry coating reinforce its corrosion resistance. • Ennoblement of Al–Zn flake coating compromises its cathodic protection. • Poor corrosion behaviour of arc sprayed Al coating caused by rough morphology. • Electrochemical noise provides adequate estimates of galvanic behaviour.

  2. VANADIUM ALLOYS

    Science.gov (United States)

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

    1959-05-12

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

  3. Cost-Effective Powder Metallurgy TiAl-Based Components For Aerospace Use, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Gamma titanium aluminide (TiAl) alloys with their low density (~3.9g/cm3), good elevated temperature strength, stiffness, creep resistance and acceptable burn and...

  4. Nonswelling alloy

    Science.gov (United States)

    Harkness, S.D.

    1975-12-23

    An aluminum alloy containing one weight percent copper has been found to be resistant to void formation and thus is useful in all nuclear applications which currently use aluminum or other aluminum alloys in reactor positions which are subjected to high neutron doses.

  5. Nonswelling alloy

    International Nuclear Information System (INIS)

    Harkness, S.D.

    1975-01-01

    An aluminum alloy containing one weight percent copper has been found to be resistant to void formation and thus is useful in all nuclear applications which currently use aluminum or other aluminum alloys in reactor positions which are subjected to high neutron doses

  6. Electrical Resistance Alloys and Low-Expansion Alloys

    DEFF Research Database (Denmark)

    Kjer, Torben

    1996-01-01

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

  7. Ductile Bulk Aluminum-Based Alloy with Good Glass-Forming Ability and High Strength

    International Nuclear Information System (INIS)

    Long-Chao, Zhuo; Shu-Jie, Pang; Hui, Wang; Tao, Zhang

    2009-01-01

    Based on a new approach for designing glassy alloy compositions, bulk Al-based alloys with good glass-forming ability (GFA) are synthesized. The cast Al 86 Si 0.5 Ni 4.06 Co 2.94 Y 6 Sc 0.5 rod with a diameter of 1 mm shows almost fully amorphous structure besides about 5% fcc-Al nucleated in the center of the rod. The bulk alloy with high Al concentration exhibits an ultrahigh yield strength of 1.18 GPa and maximum strength of 1.27 GPa as well as an obvious plastic strain of about 2.4% during compressive deformation. This light Al-based alloy with good GFA and mechanical properties is promising as a new high specific strength material with good deformability. (condensed matter: structure, mechanical and thermal properties)

  8. Stability of medium range order in Al-based metallic glass compacted by severe plastic deformation

    Energy Technology Data Exchange (ETDEWEB)

    Kovács, Zs.; Henits, P. [Department of Materials Physics, Eötvös University, P.O.B. 32, H-1518 Budapest (Hungary); Varga, L.K. [Research Institute for Solid state Physics and Optics, Hungarian Academy of Sciences, P.O.B. 49, H-1525 Budapest (Hungary); Schafler, E. [Physics of Nanostructured Materials, Faculty of Physics, University of Vienna, A-1090 Vienna (Austria); Révész, Á., E-mail: reveszadam@ludens.elte.hu [Department of Materials Physics, Eötvös University, P.O.B. 32, H-1518 Budapest (Hungary)

    2013-06-05

    Highlights: ► High pressure torsion has been applied to produce low-porosity bulk Al-based amorphous specimens. ► The compacted disks possess higher hardness than the original glass. ► Mechanical and thermal impacts have only minor effects on the glassy structure. ► Medium range order is an inherent feature of the amorphous state. -- Abstract: High pressure torsion has successfully been applied to produce low-porosity, bulk specimens from Al-based metallic glass ribbons (Al{sub 85}Y{sub 8}Ni{sub 5}Co{sub 2}, Al{sub 85}Ce{sub 8}Ni{sub 5}Co{sub 2} and Al{sub 85}Gd{sub 8}Ni{sub 5}Co{sub 2}). The compacted disks possess higher hardness than the original glass and have substantial glass fraction with nanocrystalline precipitations. Mechanical and thermal impacts have only minor effects on the glassy structure as demonstrated by the stability of the X-ray diffraction halo positions. Unchanged halos reveal that medium range order is a key characteristic of the amorphous state.

  9. Recent advances in alloy design of Ni{sub 3}Al alloys for structural use

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-12-31

    This is a comprehensive review of recent advances in R&D of Ni{sub 3}Al-based alloys for structural use at elevated temperatures in hostile environments. Recent studies indicate that polycrystalline Ni{sub 3}Al is intrinsically quite ductile at ambient temperatures, and its poor tensile ductility and brittle grain-boundary fracture are caused mainly by moisture-induced hydrogen embrittlement when the aluminide is tested in moisture- or hydrogen-containing environments. Tensile ductility is improved by alloying with substitutional and interstitial elements. Among these additives, B is most effective in suppressing environmental embrittlement and enhancing grain-boundary cohesion, resulting in a dramatic increase of tensile ductility at room temperature. Both B-doped and B-free Ni{sub 3}Al alloys exhibit brittle intergranular fracture and low ductility at intermediate temperatures (300-850 C) because of oxygen-induced embrittlement in oxidizing environments. Cr is found to be most effective in alleviating elevated-temperature embrittlement. Parallel efforts on alloy development using physical metallurgy principles have led to development of several Ni{sub 3}Al alloys for industrial use. The unique properties of these alloys are briefly discussed. 56 refs, 15 figs, 3 tabs.

  10. Superconducting alloys

    International Nuclear Information System (INIS)

    Bowers, J.E.

    1976-01-01

    Reference is made to superconductors having high critical currents. The superconductor described comprises an alloy consisting of a matrix of a Type II superconductor which is a homogeneous mixture of 50 to 95 at.% Pb and 5 to 40 at.%Bi and/or 10 to 50 at.%In. Dispersed in the matrix is a material to provide pinning centres comprising from 0.01% to 20% by volume of the alloy; this material is a stable discontinuous phase of discrete crystalline particles of Cu, Mn, Te, Se, Ni, Ca, Cr, Ce, Ge or La, either in the form of the element or a compound with a component of the matrix. These particles should have an average diameter of not more than 2μ. A method for making this alloy is described. (U.K.)

  11. Production and properties of light-metal base amorphous alloys

    International Nuclear Information System (INIS)

    Inoue, Akihisa; Masumoto, Tsuyoshi

    1993-01-01

    Light-metal base alloys with high specific strength and good corrosion resistance were produced through amorphization of Al and Mg-based alloys. The amorphous phase is formed in rapidly solidified Al-TM-Ln and Mg-TM-Ln (TM=transition metal, Ln=lanthanide metal) alloys. The highest tensile strength (σ f ) reaches 1,330 MPa for the Al base and 830 MPa for the Mg base. Furthermore, the Mg-based alloys have a large glass-forming capacity which enables to produce an amorphous phase by a metallic mold casting method. The extrusion of the Al-based amorphous powders at temperatures above crystallization temperature caused the formation of high strength materials with finely mixed structure consisting of dispersed intermetallic compounds in an Al matrix. The highest values of σ f and fatigue limit are as high as 940 and 313 MPa, respectively, at room temperature and 520 and 165 MPa at 473 K. The extruded Al-Ni-Mm alloy has already been used as machine parts and subsequent further development as practical materials is expected by taking these advantages

  12. Al based ultra-fine eutectic with high room temperature plasticity and elevated temperature strength

    Energy Technology Data Exchange (ETDEWEB)

    Tiwary, C.S., E-mail: cst311@gmail.com [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, Karnataka (India); Kashyap, S. [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, Karnataka (India); Kim, D.H. [Center for Non-Crystalline Materials, Department of Metallurgical Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Chattopadhyay, K. [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, Karnataka (India)

    2015-07-15

    Developments of aluminum alloys that can retain strength at and above 250 °C present a significant challenge. In this paper we report an ultrafine scale Al–Fe–Ni eutectic alloy with less than 3.5 at% transition metals that exhibits room temperature ultimate tensile strength of ~400 MPa with a tensile ductility of 6–8%. The yield stress under compression at 300 °C was found to be 150 MPa. We attribute it to the refinement of the microstructure that is achieved by suction casting in copper mold. The characterization using scanning and transmission electron microscopy (SEM and TEM) reveals an unique composite structure that contains the Al–Al{sub 3}Ni rod eutectic with spacing of ~90 nm enveloped by a lamellar eutectic of Al–Al{sub 9}FeNi (~140 nm). Observation of subsurface deformation under Vickers indentation using bonded interface technique reveals the presence of extensive shear banding during deformation that is responsible for the origin of ductility. The dislocation configuration in Al–Al{sub 3}Ni eutectic colony indicates accommodation of plasticity in α-Al with dislocation accumulation at the α-Al/Al{sub 3}Ni interface boundaries. In contrast the dislocation activities in the intermetallic lamellae are limited and contain set of planner dislocations across the plates. We present a detailed analysis of the fracture surface to rationalize the origin of the high strength and ductility in this class of potentially promising cast alloy.

  13. Silicon Alloying On Aluminium Based Alloy Surface

    International Nuclear Information System (INIS)

    Suryanto

    2002-01-01

    Silicon alloying on surface of aluminium based alloy was carried out using electron beam. This is performed in order to enhance tribological properties of the alloy. Silicon is considered most important alloying element in aluminium alloy, particularly for tribological components. Prior to silicon alloying. aluminium substrate were painted with binder and silicon powder and dried in a furnace. Silicon alloying were carried out in a vacuum chamber. The Silicon alloyed materials were assessed using some techniques. The results show that silicon alloying formed a composite metal-non metal system in which silicon particles are dispersed in the alloyed layer. Silicon content in the alloyed layer is about 40% while in other place is only 10.5 %. The hardness of layer changes significantly. The wear properties of the alloying alloys increase. Silicon surface alloying also reduced the coefficient of friction for sliding against a hardened steel counter face, which could otherwise be higher because of the strong adhesion of aluminium to steel. The hardness of the silicon surface alloyed material dropped when it underwent a heating cycle similar to the ion coating process. Hence, silicon alloying is not a suitable choice for use as an intermediate layer for duplex treatment

  14. The use of Nb in rapid solidified Al alloys and composites

    Energy Technology Data Exchange (ETDEWEB)

    Audebert, F., E-mail: metal@fi.uba.ar [Advanced Materials Group, Facultad de Ingeniería, Universidad de Buenos Aires, Paseo Colón 850, Ciudad de Buenos Aires 1063 (Argentina); Department of Materials, University of Oxford, Parks Road, OX1 3PH Oxford (United Kingdom); Department of Mechanical Engineering and Mathematical Sciences, Oxford Brookes University, Wheatley Campus, OX33 1HX Oxford (United Kingdom); Galano, M. [Department of Materials, University of Oxford, Parks Road, OX1 3PH Oxford (United Kingdom); Saporiti, F. [Advanced Materials Group, Facultad de Ingeniería, Universidad de Buenos Aires, Paseo Colón 850, Ciudad de Buenos Aires 1063 (Argentina)

    2014-12-05

    Highlights: • The use of Nb in RS Al alloys and composites has been reviewed. • Nb was found to improve the GFA of rapid solidified Al–Fe and Al–Ni alloys. • Nb has higher effect in increasing the corrosion resistance than RE in Al–Fe alloys. • Nb improves the stability of the Al–Fe–Cr icosahedral phase. • Nb improves strength, ductility and toughness of nanoquasicrystalline Al matrix composites. - Abstract: The worldwide requirements for reducing the energy consumption and pollution have increased the demand of new and high performance lightweight materials. The development of nanostructured Al-based alloys and composites is a key direction towards solving this demand. High energy prices and decreased availability of some alloying elements open up the opportunity to use non-conventional elements in Al alloys and composites. In this work the application of Nb in rapid solidified Al-based alloys and Al alloys matrix composites is reviewed. New results that clarify the effect of Nb on rapid solidified Al alloys and composites are also presented. It is observed that Nb stabilises the icosahedral Al–Fe/Cr clusters, enhances the glass forming ability and shifts the icosahedral phase decomposition towards higher temperatures. Nb provides higher corrosion resistance with respect to the pure Al and Al–Fe–RE (RE: rare earth) alloys in the amorphous and crystalline states. The use of Nb as a reinforcement to produce new Al alloy matrix composites is explored. It is observed that Nb provides higher strength, ductility and toughness to the nanoquasicrystalline matrix composite. Nb appears as a new key element that can improve several properties in rapid solidified Al alloys and composites.

  15. Microstructure and mechanical behavior of stir-cast Zn–27Al based composites reinforced with rice husk ash, silicon carbide, and graphite

    Directory of Open Access Journals (Sweden)

    Kenneth Kanayo Alaneme

    2017-04-01

    Full Text Available The microstructure and mechanical properties of Zn–27Al based composites reinforced with rice husk ash (RHA, silicon carbide (SiC, and graphite (Cg particles have been investigated. The Zn–27Al composites consisting of varied weight ratios of the reinforcing materials were produced using the stir casting process. Hardness test, tensile properties evaluation, fracture toughness determination, and microstructural examination, were used to characterize the composites produced. Results show that the microstructures of the composites are similar, consisting of the dendritic structure of the Zn–27Al alloy matrix with fine dispersion of the reinforcing particles. The hardness of the composites decreased with increase in the weight percent of RHA (and corresponding decrease in SiC weight percent in the reinforcement. The tensile strength and yield strength decreased slightly with increase in the weight ratio of RHA in the composites with a maximum of 8.5% and 9.6% reductions respectively observed for as much as 40% RHA (corresponding to 40% reduction in SiC in the hybrid reinforcement. Although some of the composite compositions containing RHA had slightly higher % elongation values compared with those without RHA, it was generally observed that the % elongation was invariant to the composite RHA content. The fracture toughness of the composites increases with increase in the weight percent of RHA with as much as a 20% increase obtained for as much as 40% RHA (corresponding to 40% reduction in SiC in the hybrid reinforcement.

  16. Textures and mechanical properties in rare-earth free quasicrystal reinforced Mg-Zn-Zr alloys prepared by extrusion

    International Nuclear Information System (INIS)

    Ohhashi, S.; Kato, A.; Demura, M.; Tsai, A.P.

    2011-01-01

    Highlights: → Powder-metallurgical warm extrusion made quasicrystal dispersing Mg alloys. → Mg extrusions containing quasicrystals showed randomized textures. → These extrusion showed the enhancement of mechanical properties at 150 deg. C. - Abstract: Microstructure and mechanical properties of quasicrystals dispersed Mg alloys prepared by warm extrusion of the mixtures of Mg and Zn-Mg-Zr quasicrystalline (Qc) powders have been studied. Strong texture oriented along a [101-bar 0] direction observed in pure Mg was reduced in Qc-dispersed samples, as verified by pole figure method and electron back scattering diffraction. The ultimate tensile strengths at 150 deg. C for Qc-dispersed extrusions were much higher than 110 MPa for pure Mg, which drastically reached 156 MPa for 15 wt.% Qc by preventing the motion of dislocations. Elongation was improved by the randomization of grain orientation: from 5.7% for pure Mg to 12.9% for 10 wt.% Qc at room temperature; from 15% for pure Mg to 37.1% for 5 wt.% Qc at 150 deg. C.

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

    Energy Technology Data Exchange (ETDEWEB)

    Valkov, S., E-mail: stsvalkov@gmail.com [Institute of Electronics, Bulgarian Academy of Science, 72 Tzarigradsko Chaussee blvd., 1784 Sofia (Bulgaria); Petrov, P. [Institute of Electronics, Bulgarian Academy of Science, 72 Tzarigradsko Chaussee blvd., 1784 Sofia (Bulgaria); Lazarova, R. [Institute of Metal Science, Equipment and Technologies with Hydro and Aerodynamics Center, Bulgarian Academy of Science, 67 Shipchenski Prohod blvd., 1574 Sofia (Bulgaria); Bezdushnyi, R. [Department of Solid State Physics and Microelectronics, Faculty of Physics, Sofia University “St. Kliment Ohridsky”, 1164 Sofia (Bulgaria); Dechev, D. [Institute of Electronics, Bulgarian Academy of Science, 72 Tzarigradsko Chaussee blvd., 1784 Sofia (Bulgaria)

    2016-12-15

    Highlights: • Al–Ti–Nb surface alloys have been successfully obtained by electron-beam surface alloying technology. • The alloys consist of (Ti,Nb)Al{sub 3} fractions, distributed in the biphasic structure of (Ti,Nb)Al{sub 3} particles dispersed in α-Al. • The alloying speed does not affect the lattice parameters of (Ti,Nb)Al{sub 3} and, does not form additional stresses, strains etc. • It was found that lower velocity of the specimen motion during the alloying process develops more homogeneous structures. • The measured hardness of (Ti,Nb)Al{sub 3} compound reaches 775 HV[kg/cm{sup 2}] which is much greater than the values of NbAl{sub 3}. - Abstract: 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: V{sub 1} = 0.5 cm/s and V{sub 2} = 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)Al{sub 3} fractions randomly distributed in biphasic structure of intermetallic (Ti,Nb)Al{sub 3} particles, dispersed in α-Al solid solution. The evaluated (Ti,Nb)Al{sub 3} 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

  18. Al-based anti-corrosion and T-permeation barrier development for future DEMO blankets

    International Nuclear Information System (INIS)

    Krauss, W.; Konys, J.; Holstein, N.; Zimmermann, H.

    2011-01-01

    In the Helium-Cooled-Liquid-Lead (HCLL) design of Test-Blanket-Modules (TBM's) for a future fusion power plant Pb-15.7Li is used as liquid breeder which is in direct contact with the structure material, e.g. EUROFER steel. Compatibility testing showed that high corrosion attack appears and that the dissolved steel components form precipitates with a high risk of system blockages. A reliable operation needs coatings as corrosion barriers. The earlier developed Hot-Dip Aluminisation (HDA) process has shown that Al-based scales can act as anti-corrosion as well as T-permeation barriers. Meanwhile two advanced electro-chemically based processes for deposition of Al-scales were successfully developed. The first (ECA = Electro-Chemical Al-deposition) is working with an organic electrolyte and the second one (ECX = Electro-Chemical-X-metal-deposition) is based on ionic liquids. Coatings in the μm-range were deposited homogeneously with exact controllable thicknesses. Metallurgical investigations showed the successful generation of protective scales and compatibility testing demonstrated the barrier function.

  19. Co-Zn-Al based hydrotalcites as catalysts for Fischer-Tropsch process

    Energy Technology Data Exchange (ETDEWEB)

    Bianchi, C.L.; Pirola, C.; Boffito, D.C.; Di Fronzo, A. [Univ. degli Studi di Milano (Italy). Dipt. di Chimica Fisica ed Elettrochimica; Di Michele, A. [Univ. degli Studi di Perugia (Italy). Dipt. di Fisica; Vivani, R.; Nocchetti, M.; Bastianini, M.; Gatto, S. [Univ. degli Studi di Perugia (Italy). Dipt. di Chimica

    2011-07-01

    Co-Zn-Al based hydrotalcites have been investigated as catalysts for the well-known Fischer- Tropsch synthesis. A series of ternary hydrotalcites in nitrate form was prepared with the urea method in order to obtain active catalysts for the above mentioned process. The thermal activation at 350 C gives raise to finely dispersed metallic Co on the mixed oxides, so resulting in retaining the metal distribution of the parent compounds. An optimization study concerning the amount of cobalt of the prepared catalysts (range 15-70% mol, metal based) and the reaction temperature (220-260 C) is reported. All the samples have been fully characterized (BET, ICP-OES, XRPD, TG-DTA, FT-IR, SEM and TEM) and tested in a laboratory pilot plant. Tests to evaluate the stability of these materials were carried out in stressed conditions concerning both the activation and the operating temperatures and pressures (up to 350 C and 2.0 MPa). The obtained results suggest the possibility of using synthetic hydrotalcites as suitable Co-based catalysts for the Fischer-Tropsch synthesis. (orig.)

  20. Al-based anti-corrosion and T-permeation barrier development for future DEMO blankets

    Energy Technology Data Exchange (ETDEWEB)

    Krauss, W., E-mail: wolfgang.krauss@kit.edu [Karlsruhe Institute of Technology, Hermann von Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Konys, J.; Holstein, N.; Zimmermann, H. [Karlsruhe Institute of Technology, Hermann von Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2011-10-01

    In the Helium-Cooled-Liquid-Lead (HCLL) design of Test-Blanket-Modules (TBM's) for a future fusion power plant Pb-15.7Li is used as liquid breeder which is in direct contact with the structure material, e.g. EUROFER steel. Compatibility testing showed that high corrosion attack appears and that the dissolved steel components form precipitates with a high risk of system blockages. A reliable operation needs coatings as corrosion barriers. The earlier developed Hot-Dip Aluminisation (HDA) process has shown that Al-based scales can act as anti-corrosion as well as T-permeation barriers. Meanwhile two advanced electro-chemically based processes for deposition of Al-scales were successfully developed. The first (ECA = Electro-Chemical Al-deposition) is working with an organic electrolyte and the second one (ECX = Electro-Chemical-X-metal-deposition) is based on ionic liquids. Coatings in the {mu}m-range were deposited homogeneously with exact controllable thicknesses. Metallurgical investigations showed the successful generation of protective scales and compatibility testing demonstrated the barrier function.

  1. Phase stability and decomposition processes in Ti-Al based intermetallics

    Energy Technology Data Exchange (ETDEWEB)

    Nakai, Kiyomichi [Department of Materials Science and Engineering, Faculty of Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama 790 (Japan); Ono, Toshiaki [Department of Materials Science and Engineering, Faculty of Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama 790 (Japan); Ohtsubo, Hiroyuki [Department of Materials Science and Engineering, Faculty of Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama 790 (Japan); Ohmori, Yasuya [Department of Materials Science and Engineering, Faculty of Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama 790 (Japan)

    1995-02-28

    The high-temperature phase equilibria and the phase decomposition of {alpha} and {beta} phases were studied by crystallographic analysis of the solidification microstructures of Ti-48at.%Al and Ti-48at.%Al-2at.%X (X=Mn, Cr, Mo) alloys. The effects on the phase stability of Zr and O atoms penetrating from the specimen surface were also examined for Ti-48at.%Al and Ti-50at.%Al alloys. The third elements Cr and Mo shift the {beta} phase region to higher Al concentrations, and the {beta} phase is ordered to the {beta}{sub 2} phase. The Zr and O atoms stabilize {beta} and {alpha} phases respectively. In the Zr-stabilized {beta} phase, {alpha}{sub 2} laths form with accompanying surface relief, and stacking faults which relax the elastic strain owing to lattice deformation are introduced after formation of {alpha}{sub 2} order domains. Thus shear is thought to operate after the phase transition from {beta} to {alpha}{sub 2} by short-range diffusion. A similar analysis was conducted for the Ti-Al binary system, and the transformation was interpreted from the CCT diagram constructed qualitatively. ((orig.))

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

    Directory of Open Access Journals (Sweden)

    I. Ivanic

    2014-09-01

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

  3. Microstructure and mechanical properties of cast Ti-47Al-2Cr-2Nb alloy melted in various crucibles

    Directory of Open Access Journals (Sweden)

    Wang Ligang

    2012-02-01

    Full Text Available The main factors limiting the mass production of TiAl-based components are the high reactivity of TiAl-based alloys with the crucible or mould at high temperature. In this work, various crucibles (e.g. CaO, Y2O3 ceramic crucibles and water-cooled copper crucible were used to fabricate the Ti-47Al-2Cr-2Nb alloy in a vacuum induction furnace. The effects of crucible materials and melting parameters on the microstructure and mechanical properties of the alloy were analyzed by means of microstructure observation, chemical analysis, tensile test and fracture surface observation. The possibilities of melting TiAl alloys in crucibles made of CaO and Y2O3 refractory materials were also discussed.

  4. Thermo-mechanical processing (TMP) of Ti-48Al-2Nb-2Cr based alloys

    International Nuclear Information System (INIS)

    Fuchs, G.E.

    1995-02-01

    The effects of heat treatment and deformation processing on the microstructures and properties of γ-TiAl based alloys produced by ingot metallurgy (I/M) and powder metallurgy (P/M) techniques were examined. The alloy selected for this work is the second generation γ-TiAl based alloy -- Ti-48Al-2Nb-2Cr (at %). Homogenization of I/M samples was performed at a variety of temperatures, followed by hot working by isothermal forging. P/M samples were prepared from gas atomized powders, consolidated by both HIP and extrusion and some of the HIPed material was then hot worked by isothermal forging. The effects of processing, heat treatment and hot working on the microstructures and properties will be discussed

  5. Current research progress in grain refinement of cast magnesium alloys: A review article

    International Nuclear Information System (INIS)

    Ali, Yahia; Qiu, Dong; Jiang, Bin; Pan, Fusheng; Zhang, Ming-Xing

    2015-01-01

    Grain refinement of cast magnesium alloys, particularly in magnesium–aluminium (Mg–Al) based alloys, has been an active research topic in the past two decades, because it has been considered as one of the most effective approaches to simultaneously increase the strength, ductility and formability. The development of new grain refiners was normally based on the theories/models that were established through comprehensive and considerable studies of grain refinement in cast Al alloys. Generally, grain refinement in cast Al can be achieved through either inoculation treatment, which is a process of adding, or in situ forming, foreign particles to promote heterogeneous nucleation rate, or restricting grain growth by controlling the constitutional supercooling or both. But, the concrete and tangible grain refinement mechanism in cast metals is still not fully understood and there are a number of controversies. Therefore, most of the new developed grain refiners for Mg–Al based alloys are not as efficient as the commercially available ones, such as zirconium in non-Al containing Mg alloys. To facilitate the research in grain refinement of cast magnesium alloys, this review starts with highlighting the theoretical aspects of grain refinement in cast metals, followed by reviewing the latest research progress in grain refinement of magnesium alloys in terms of the solute effect and potent nucleants

  6. Current research progress in grain refinement of cast magnesium alloys: A review article

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Yahia; Qiu, Dong [School of Mechanical and Mining Engineering, University of Queensland, St Lucia, QLD 4072 (Australia); Jiang, Bin; Pan, Fusheng [College of Materials Science and Engineering, Chongqing University, Chongqing 400030 (China); Zhang, Ming-Xing, E-mail: Mingxing.Zhang@uq.edu.au [School of Mechanical and Mining Engineering, University of Queensland, St Lucia, QLD 4072 (Australia)

    2015-01-15

    Grain refinement of cast magnesium alloys, particularly in magnesium–aluminium (Mg–Al) based alloys, has been an active research topic in the past two decades, because it has been considered as one of the most effective approaches to simultaneously increase the strength, ductility and formability. The development of new grain refiners was normally based on the theories/models that were established through comprehensive and considerable studies of grain refinement in cast Al alloys. Generally, grain refinement in cast Al can be achieved through either inoculation treatment, which is a process of adding, or in situ forming, foreign particles to promote heterogeneous nucleation rate, or restricting grain growth by controlling the constitutional supercooling or both. But, the concrete and tangible grain refinement mechanism in cast metals is still not fully understood and there are a number of controversies. Therefore, most of the new developed grain refiners for Mg–Al based alloys are not as efficient as the commercially available ones, such as zirconium in non-Al containing Mg alloys. To facilitate the research in grain refinement of cast magnesium alloys, this review starts with highlighting the theoretical aspects of grain refinement in cast metals, followed by reviewing the latest research progress in grain refinement of magnesium alloys in terms of the solute effect and potent nucleants.

  7. Mechanical alloying and self-propagating high-temperature synthesis of stable icosahedral quasicrystals

    International Nuclear Information System (INIS)

    Bokhonov, B.B.

    2008-01-01

    The phase evolution of the mechanically alloyed ternary 63%Al + 25%Cu + 12%Fe and 65%Al + 20%Cu + 15%Fe powder mixtures with milling time has been studied by X-ray diffraction method. It was found that an icosahedral quasicrystalline phase was formed directly during high-energy ball milling of the Al-Cu-Fe mixtures. The X-ray and scanning electron microscopic investigations demonstrated the possibility to use self-propagating high-temperature synthesis (SHS) in combination with preliminary mechanical activation for the synthesis of stable icosahedral quasicrystals. The typical morphology of the Al 63 Cu 25 Fe 12 icosahedral quasicrystals formed in the SHS process is a pentagonal dodecahedron with a size of 3-5 mm. The phase composition of the SHS products depends on the time of preliminary mechanical activation. The content of cubic intermetallic phase in SHS products increases with the time of preliminary mechanical activation of the 63%Al + 25%Cu + 12%Fe powder mixtures

  8. Design and properties of advanced {gamma}(TiAl) alloys

    Energy Technology Data Exchange (ETDEWEB)

    Appel, F; Clemens, H; Oehring, M [Institute for Materials Research, GKSS Research Centre, Max-Planck-Strasse, D-21502 Geesthacht (Germany)

    2001-07-01

    Intermetallic titanium aluminides are one of the few classes of emerging materials that have the potential to be used in demanding high-temperature structural applications whenever specific strength and stiffness are of major concern. However, in order to effectively replace the heavier nickel-base superalloys currently use, titanium aluminides must combine a wide range of mechanical property capabilities. Advanced alloy designs are tailored for strength, toughness, creep resistance, and environmental stability. Some of these concerns are addressed in the present paper through global commentary on the physical metallurgy and technology of gamma TiAl-base alloys. Particular emphasis is paid on recent developments of TiAl alloys with enhanced high-temperature capability. (author)

  9. Design and properties of advanced γ(TiAl) alloys

    International Nuclear Information System (INIS)

    Appel, F.; Clemens, H.; Oehring, M.

    2001-01-01

    Intermetallic titanium aluminides are one of the few classes of emerging materials that have the potential to be used in demanding high-temperature structural applications whenever specific strength and stiffness are of major concern. However, in order to effectively replace the heavier nickel-base superalloys currently use, titanium aluminides must combine a wide range of mechanical property capabilities. Advanced alloy designs are tailored for strength, toughness, creep resistance, and environmental stability. Some of these concerns are addressed in the present paper through global commentary on the physical metallurgy and technology of gamma TiAl-base alloys. Particular emphasis is paid on recent developments of TiAl alloys with enhanced high-temperature capability. (author)

  10. Prospects for designing structural cast eutectic alloys on Al-Ce-Ni system base

    International Nuclear Information System (INIS)

    Belov, N.A.; Naumova, E.S.

    1996-01-01

    The phase diagram of Al-Ce-Ni system is built for an aluminium corner at component concentration up to 16 mass %Ce and 8 mass%Ni. A ternary eutectic reaction is established at 12%Ce, 5%Ni and 626 deg C. The ternary eutectic alloy is similar in structure to rapidly cooled Al base alloys with transition metals. The possibility to design new cast alloys based on three-phase (Al)+NiAl 3 +CeAl 4 eutectics is under consideration. Al-Zn-Mg-Cu, Al-Sc and Al-Zr base alloys can be used as (Al) constituent of the eutectics. The new alloys may be considered as heat resistant ones due to the fact that no structural changes are observed in castings on heating up to 350 deg C. 18 refs.; 4 figs.; 2 tabs

  11. The shock Hugoniot of the intermetallic alloy Ti-46.5Al-2Nb-2Cr

    International Nuclear Information System (INIS)

    Millett, Jeremy; Gray, George T. Rusty III; Bourne, Neil

    2000-01-01

    Plate impact experiments were conducted on a γ-titanium aluminide (TiAl) based ordered intermetallic alloy. Stress measurements were recorded using manganin stress gauges supported on the back of TiAl targets using polymethylmethacrylate windows. The Hugoniot in stress-particle velocity space for this TiAl alloy was deduced using impedance matching techniques. The results in this study are compared to the known Hugoniot data of the common alpha-beta engineering Ti-based alloy Ti-6Al-4V. The results of the current study on the intermetallic alloy TiAl support that TiAl possesses a significantly higher stress for a given particle velocity than the two-phase Ti-6Al-4V alloy. (c) 2000 American Institute of Physics

  12. Translating VDM to Alloy

    DEFF Research Database (Denmark)

    Lausdahl, Kenneth

    2013-01-01

    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...

  13. Photocatalytic property and structural stability of CuAl-based layered double hydroxides

    International Nuclear Information System (INIS)

    Lv, Ming; Liu, Haiqiang

    2015-01-01

    Three types of CuMAl layered double hydroxides (LDHs, M=Mg, Zn, Ni) were successfully synthesized by coprecipitation. Powder X-ray diffraction (XRD), inductively coupled plasma atomic emission spectrometry (ICP-AES) and UV–Vis diffuse reflectance spectrum (UV–vis) were used to confirm the formation of as-synthesized solids with good crystal structure. The photocatalytic activity of those LDH materials for CO 2 reduction under visible light was investigated. The experimental results show that CuNiAl-LDHs with narrowest band gap and largest surface areas behave highest efficiency for methanol generation under visible light compared with CuMgAl-LDHs and CuZnAl-LDHs. The CuNiAL-LDH showed high yield for methanol production i.e. 0.210 mmol/g h, which was high efficient. In addition, the influence of the different M 2+ on the structures and stability of the CuMAl-LDHs was also investigated by analyzing the geometric parameters, electronic arrangement, charge populations, hydrogen-bonding, and binding energies by density functional theory (DFT) analysis. The theoretical calculation results show that the chemical stability of LDH materials followed the order of CuMgAl-LDHs>CuZnAl-LDHs>CuNiAl-LDHs, which is just opposite with the photocatalytic activity and band gaps of three materials. - Graphical abstract: The host–guest calculation models and XRD patterns of CuMAl-LDHs: CuMgAl-LDHs (a), CuZnAl-LDHs (b) and CuNiAl-LDHs (c). - Highlights: • Three types of CuMAl layered double hydroxides (LDHs, M=Mg, Zn, Ni) has been synthesized. • CuMgNi shows narrower band gap and more excellent textural properties than other LDHs. • The band gap: CuMgAlAl based on result from UV–vis analysis. • CuMgAl shows the highest stability and lowest photocatalytic activity, while CuNiAl just opposite

  14. Mechanical properties and dual atmosphere tolerance of Ag-Al based braze

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Yong; Choi, Jung-Pyung; Scott Weil, K. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States)

    2008-07-15

    In this paper, the effects of aluminum on the microstructure, mechanical properties, and high temperature dual atmosphere tolerance of silver and silver-copper oxide filler metals were investigated. It was found that joints brazed with binary Ag-Al braze foils containing more than 2 at% Al retained a metallic form of aluminum within the metallic braze filler matrix after brazing at 1000 C in air. The bend strengths of these joints decreased with increasing aluminum content due to the formation of interfacial aluminum oxide. However, the existence of metallic aluminum in the braze filler matrix appeared to enhance the high-temperature dual atmosphere tolerance of the silver-based braze filler, which displayed measurably less porosity after 1000h of exposure at 800 C in a dual reducing/oxidizing atmosphere environment than unalloyed silver. A series of binary and ternary braze pastes based on the Ag-Al(-Cu) system were also formulated as potential pSOFC (planar solid oxide fuel cell) sealants. Model alumina joints brazed with these pastes exhibited an increase in bend strength with increasing copper content. However, unlike the binary Ag-Al filler metals, the ternary compositions often retained no protective metallic aluminum after brazing. Thus, while the addition of copper improves filler metal wettability and, therefore, joint strength in the Ag-Al alloys, it appears to reduce the dual atmosphere tolerance of these filler metals. (author)

  15. Phase separation and nanocrystal formation in Al-based metallic glasses

    International Nuclear Information System (INIS)

    Antonowicz, Jerzy

    2007-01-01

    Nanocrystallization in a group of Al-RE and Al-RE-TM (RE = rare earth, TM = transition metal) melt-spun amorphous alloys was studied using in situ small- and wide-angle X-ray scattering techniques (SAXS/WAXS) and transmission electron microscopy (TEM). The SAXS/WAXS measurements were carried out during isothermal annealing at temperatures close to crystallization point. A continuously growing interference maximum shifting progressively toward lower angles was found to develop in SAXS regime. Simultaneously taken WAXS spectra reveal formation of the primary fcc-Al nanocrystalline phase. The presence of the SAXS signal maximum indicates the spatial correlation between the compositional fluctuations. The peak position decay is an evidence of an increase of the fluctuation spacing characteristic for the coarsening stage of phase separation. The SAXS/WAXS data analysis indicates that amorphous phase decomposition triggers and controls the fcc-Al nanocrystalline phase formation. The glassy phase initially decomposes into Al-rich and RE-rich regions with typical lengths scale of about 10 nm. The nanocrystals nucleate preferentially inside the Al-rich amorphous regions and their growth is constrained by the region size because of the sluggish atomic diffusion in the RE-rich zones. A different crystallization mechanism is demonstrated in Al-Y-Ni-Co glass where WAXS spectra show formation of the fcc-Al primary phase but no interference peak in SAXS regime was found

  16. Effect of alloying elements on martensitic transformation in the binary NiAl(β) phase alloys

    International Nuclear Information System (INIS)

    Kainuma, R.; Ohtani, H.; Ishida, K.

    1996-01-01

    The characteristics of the B2(β) to L1 0 (β') martensitic transformation in NiAl base alloys containing a small amount of third elements have been investigated by differential scanning calorimetry (DSC), X-ray diffraction (XRD), and transmission electron microscopy (TEM). It is found that in addition to the normal L1 0 (3R) martensite, the 7R martensite is also present in the ternary alloys containing Ti, Mo, Ag, Ta, or Zr. While the addition of third elements X (X: Ti, V, Cr, Mn, Fe, Zr, Nb, Mo, Ta, W, and Si) to the binary Ni 64 Al 36 alloy stabilizes the parent β phase, thereby lowering the M s temperature, addition of third elements such as Co, Cu, or Ag destabilizes the β phase, increasing the M s temperature. The occurrence of the 7R martensite structure is attributed to solid solution hardening arising from the difference in atomic size between Ni and Al and the third elements added. The variation in M s temperature with third element additions is primarily ascribed to the difference in lattice stabilities of the bcc and fcc phases of the alloying elements

  17. Steel alloys

    International Nuclear Information System (INIS)

    Bloom, E.E.; Stiegler, J.O.; Rowcliffe, A.F.; Leitnaker, J.M.

    1977-01-01

    The invention deals with a fuel element for fast breeder reactors. It consits essentially of a uranium oxide, nitride, or carbide or a mixture of these fuels with a plutonium or thorium oxide, nitride, or carbide. The fuel elements are coated with an austenitic stainless steel alloy. Inside the fuel elements, vacancies or small cavities are produced by neutron effects which causes the steel coating to swell. According to the invention, swelling is prevented by a modification of type 304, 316, 321, or 12 K 72HV commercial steels. They consist mainly of Fe, Cr, and Ni in a ratio determined by a temary diagram. They may also contain 1.8 to 2.3% by weight of Mo and a fraction of Si (0.7 to 2% by weight) and Ti(0.10 to 0.5% by weight) to prevent cavity formation. They are structurally modified by cold working. (IHOE) [de

  18. Enhanced WWTP effluent organic matter removal in hybrid ozonation-coagulation (HOC) process catalyzed by Al-based coagulant

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Xin [School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi Province, 710055 (China); Jin, Pengkang, E-mail: pkjin@hotmail.com [School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi Province, 710055 (China); Hou, Rui [School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi Province, 710055 (China); Yang, Lei [Department of Materials Science and Engineering, Monash University, Clayton, VIC, 3800 (Australia); Wang, Xiaochang C., E-mail: xcwang@xauat.edu.cn [School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi Province, 710055 (China)

    2017-04-05

    Highlights: • A novel HOC process was firstly put forward to apply in wastewater reclamation. • Interactions between ozone and Al-based coagulants was found in the HOC process. • Ozonation can be catalyzed and enhanced by Al-based coagulants in the HOC process. • HOC process showed better organics removal than pre-ozonation-coagulation process. - Abstract: A novel hybrid ozonation-coagulation (HOC) process was developed for application in wastewater reclamation. In this process, ozonation and coagulation occurred simultaneously within a single unit. Compared with the conventional pre-ozonation-coagulation process, the HOC process exhibited much better performance in removing dissolved organic matters. In particular, the maximal organic matters removal efficiency was obtained at the ozone dosage of 1 mgO{sub 3}/mg DOC at each pH value (pH 5, 7 and 9). In order to interpret the mechanism of the HOC process, ozone decomposition was monitored. The results indicated that ozone decomposed much faster in the HOC process. Moreover, by using the reagent of O{sub 3}-resistant hydroxyl radical (·OH) probe compound, para-chlorobenzoic acid (pCBA), and electron paramagnetic resonance (EPR) analysis, it was observed that the HOC process generated higher content of ·OH compared with pre-ozonation process. This indicates that the ·OH oxidation reaction as the key step can be catalyzed and enhanced by Al-based coagulants and their hydrolyzed products in this developed process. Thus, based on the catalytic effects of Al-based coagulants on ozonation, the HOC process provides a promising alternative to the conventional technology for wastewater reclamation in terms of higher efficiency.

  19. Influence of Y, Gd and Sm on the glass forming ability and thermal crystallization of aluminum based alloy

    International Nuclear Information System (INIS)

    Aliaga, L.C.R.; Bolfarini, C.; Kiminami, C.S.; Botta Filho, W.J.; Danez, G.P.

    2010-01-01

    Al-based amorphous alloys represent an important family of metals and a great scientific activity has been devoted to determine the main features of both glass forming ability (GFA) and crystallization behavior in order to have a comprehensive framework aimed at potential technological applications. Nowadays, it is well known that the best Al-based amorphous alloys are formed in ternary systems such as Al- RE-TM, where RE is a rare earth and TM a transition metal. This paper presents results of research in Al 85 Ni 10 RE 5 alloys (RE = Y, Gd and Sm). Amorphous ribbons were processed by melt-spinning under the same conditions and subsequently characterized by x-ray diffraction (XRD) and differential scanning calorimetry (DSC). Results show appreciable micro structural differences as function of the rare earth, thus crystal is obtained for Y, nano-glassy for Gd and, fully amorphous structure for Sm. (author)

  20. Alloy Fabrication Laboratory

    Data.gov (United States)

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

  1. Controlled Thermal Expansion Alloys

    Data.gov (United States)

    National Aeronautics and Space Administration — There has always been a need for controlled thermal expansion alloys suitable for mounting optics and detectors in spacecraft applications.  These alloys help...

  2. Electronic structure of alloys

    International Nuclear Information System (INIS)

    Ehrenreich, H.; Schwartz, L.M.

    1976-01-01

    The description of electronic properties of binary substitutional alloys within the single particle approximation is reviewed. Emphasis is placed on a didactic exposition of the equilibrium properties of the transport and magnetic properties of such alloys. Topics covered include: multiple scattering theory; the single band alloy; formal extensions of the theory; the alloy potential; realistic model state densities; the s-d model; and the muffin tin model. 43 figures, 3 tables, 151 references

  3. Dislocations in decagonal Al-Cu-Co alloy

    International Nuclear Information System (INIS)

    Zhang, Z.; Urban, K.

    1990-01-01

    Dislocations have been observed for the first time in a decagonal quasicrystalline structure. The lattice defects found in Al 65 Cu 20 Co 15 decagonal phase give electron diffraction contrast similar to that found in normal-crystalline materials. (author). 14 refs, 3 figs

  4. Effect of Particle Size on Microstructure and Mechanical Properties of Al-Based Composite Reinforced with 10 Vol.% Mechanically Alloyed Mg-7.4%Al Particles

    Directory of Open Access Journals (Sweden)

    Anil K. Chaubey

    2016-11-01

    Full Text Available The effect of Mg-7.4%Al reinforcement particle size on the microstructure and mechanical properties in pure Al matrix composites was investigated. The samples were prepared by hot consolidation using 10 vol.% reinforcement in different size ranges, D, 0 < D < 20 µm (0–20 µm, 20 ≤ D < 40 µm (20–40 µm, 40 ≤ D < 80 µm (40–80 µm and 80 ≤ D < 100 µm (80–100 µm. The result reveals that particle size has a strong influence on the yield strength, ultimate tensile strength and percentage elongation. As the particle size decreases from 80 ≤ D < 100 µm to 0 < D < 20 µm, both tensile strength and ductility increases from 195 MPa to 295 MPa and 3% to 4% respectively, due to the reduced ligament size and particle fracturing. Wear test results also corroborate the size effect, where accelerated wear is observed in the composite samples reinforced with coarse particles.

  5. Aluminothermic Reduction-Molten Salt Electrolysis Using Inert Anode for Oxygen and Al-Base Alloy Extraction from Lunar Soil Simulant

    Science.gov (United States)

    Xie, Kaiyu; Shi, Zhongning; Xu, Junli; Hu, Xianwei; Gao, Bingliang; Wang, Zhaowen

    2017-10-01

    Aluminothermic reduction-electrolysis using an inert anode process is proposed to extract oxygen and metals from Minnesota Lunar Simulant-1 (MLS-1). Effective aluminothermic reduction between dissolved MLS-1 and dissolved metal aluminum was achieved in cryolite salt media. The product phases obtained by aluminothermic reduction at 980°C for 4 h were Al, Si, and Al5FeSi, while the chemical components were 79.71 mass% aluminum, 12.03 mass% silicon, 5.91 mass% iron, and 2.35 mass% titanium. The cryolite salt containing Al2O3 was subsequently electrolyzed with Fe0.58-Ni0.42 inert anode at 960°C for 4 h. Oxygen was evolved at the anode with an anodic current efficiency of 78.28%. The results demonstrate that this two-step process is remarkably feasible for the extraterrestrial extraction of oxygen and metals. This process will help expand the existing in situ resource utilization methods.

  6. High strength alloys

    Science.gov (United States)

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

    2010-08-31

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

  7. Biocompatibility of dental alloys

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-10-01

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

  8. Strength properties and structure of a submicrocrystalline Al-Mg-Mn alloy under shock compression

    Science.gov (United States)

    Petrova, A. N.; Brodova, I. G.; Razorenov, S. V.

    2017-06-01

    The results of studying the strength of a submicrocrystalline aluminum A5083 alloy (chemical composition was 4.4Mg-0.6Mn-0.11Si-0.23Fe-0.03Cr-0.02Cu-0.06Ti wt % and Al base) under shockwave compression are presented. The submicrocrystalline structure of the alloy was produced in the process of dynamic channel-angular pressing at a strain rate of 104 s-1. The average size of crystallites in the alloy was 180-460 nm. Hugoniot elastic limit σHEL, dynamic yield stress σy, and the spall strength σSP of the submicrocrystalline alloy were determined based on the free-surface velocity profiles of samples during shock compression. It has been established that upon shock compression, the σHEL and σy of the submicrocrystalline alloy are higher than those of the coarse-grained alloy and σsp does not depend on the grain size. The maximum value of σHEL reached for the submicrocrystalline alloy is 0.66 GPa, which is greater than that in the coarse-crystalline alloy by 78%. The dynamic yield stress is σy = 0.31 GPa, which is higher than that of the coarse-crystalline alloy by 63%. The spall strength is σsp = 1.49 GPa. The evolution of the submicrocrystalline structure of the alloy during shock compression was studied. It has been established that a mixed nonequilibrium grain-subgrain structure with a fragment size of about 400 nm is retained after shock compression, and the dislocation density and the hardness of the alloy are increased.

  9. Effect of AlB2-Mg interaction on the mechanical properties of Al-based composites

    International Nuclear Information System (INIS)

    Calderon, Hermes E.; Hidalgo, Ruth G.I.; Melgarejo, Z. Humberto; Suarez, O. Marcelo

    2010-01-01

    A series of Al-based composites with a matrix containing 2.5 wt.%Cu and 1 wt.%Mg, and reinforced with Al diborides was manufactured and characterized via microscopy and mechanical testing. The impact resistance of the composites revealed interaction between AlB 2 dispersoids and Mg originally present in the Al matrix. An unexpected increase in the absorbed impact energy of composites with diborides prompted complementary experiments leading to this finding. Hardness tests were correlated to those results and provided further evidence of the interaction between Mg and the dispersoids. Additional energy dispersive spectroscopy (EDS) analysis and X-ray diffraction tests supported with crystal modeling demonstrated that Mg effectively diffused into the AlB 2 crystal producing a doped structure with an Al 1-x Mg x B 2 formula where x lies between 0.08 and 0.15.

  10. Development of a TiAl Alloy by Spark Plasma Sintering

    Science.gov (United States)

    Couret, Alain; Voisin, Thomas; Thomas, Marc; Monchoux, Jean-Philippe

    2017-12-01

    Spark plasma sintering (SPS) is a consolidated powder metallurgy process for which the powder sintering is achieved through an applied electric current. The present article aims to describe the method we employed to develop a TiAl-based alloy adjusted for this SPS process. Owing to its enhanced mechanical properties, this alloy was found to fully match the industrial specifications for the aeronautic and automotive industries, which require a high strength at high temperature and a reasonably good ductility at room temperature. A step-by-step method was followed for this alloy development. Starting from a basic study on the as-SPSed GE alloy (Ti-48Al-2Cr-2Nb) in which the influence of the microstructure was studied, the microstructure-alloy composition relationships were then investigated to increase the mechanical properties. As a result of this study, we concluded that tungsten had to be the major alloying element to improve the resistance at high temperature and a careful addition of boron would serve the properties at room temperature. Thus, we developed the IRIS alloy (Ti-48Al-2W-0.08B). Its microstructure and mechanical properties are described here.

  11. Self-forming Al oxide barrier for nanoscale Cu interconnects created by hybrid atomic layer deposition of Cu–Al alloy

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jae-Hyung; Han, Dong-Suk; Kang, You-Jin [Division of Nanoscale Semiconductor Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Shin, So-Ra; Park, Jong-Wan, E-mail: jwpark@hanyang.ac.kr [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2014-01-15

    The authors synthesized a Cu–Al alloy by employing alternating atomic layer deposition (ALD) surface reactions using Cu and Al precursors, respectively. By alternating between these two ALD surface chemistries, the authors fabricated ALD Cu–Al alloy. Cu was deposited using bis(1-dimethylamino-2-methyl-2-butoxy) copper as a precursor and H{sub 2} plasma, while Al was deposited using trimethylaluminum as the precursor and H{sub 2} plasma. The Al atomic percent in the Cu–Al alloy films varied from 0 to 15.6 at. %. Transmission electron microscopy revealed that a uniform Al-based interlayer self-formed at the interface after annealing. To evaluate the barrier properties of the Al-based interlayer and adhesion between the Cu–Al alloy film and SiO{sub 2} dielectric, thermal stability and peel-off adhesion tests were performed, respectively. The Al-based interlayer showed similar thermal stability and adhesion to the reference Mn-based interlayer. Our results indicate that Cu–Al alloys formed by alternating ALD are suitable seed layer materials for Cu interconnects.

  12. Self-forming Al oxide barrier for nanoscale Cu interconnects created by hybrid atomic layer deposition of Cu–Al alloy

    International Nuclear Information System (INIS)

    Park, Jae-Hyung; Han, Dong-Suk; Kang, You-Jin; Shin, So-Ra; Park, Jong-Wan

    2014-01-01

    The authors synthesized a Cu–Al alloy by employing alternating atomic layer deposition (ALD) surface reactions using Cu and Al precursors, respectively. By alternating between these two ALD surface chemistries, the authors fabricated ALD Cu–Al alloy. Cu was deposited using bis(1-dimethylamino-2-methyl-2-butoxy) copper as a precursor and H 2 plasma, while Al was deposited using trimethylaluminum as the precursor and H 2 plasma. The Al atomic percent in the Cu–Al alloy films varied from 0 to 15.6 at. %. Transmission electron microscopy revealed that a uniform Al-based interlayer self-formed at the interface after annealing. To evaluate the barrier properties of the Al-based interlayer and adhesion between the Cu–Al alloy film and SiO 2 dielectric, thermal stability and peel-off adhesion tests were performed, respectively. The Al-based interlayer showed similar thermal stability and adhesion to the reference Mn-based interlayer. Our results indicate that Cu–Al alloys formed by alternating ALD are suitable seed layer materials for Cu interconnects

  13. Evaluation of liquid fragility and thermal stability of Al-based metallic glasses by equivalent structure parameter

    International Nuclear Information System (INIS)

    Li Xuelian; Bian Xiufang; Hu Lina

    2010-01-01

    Based on extended Ideal-Atomic-Packing model, we propose an equivalent structure parameter '6x+11y' to evaluate fragility and thermal stability of Al-TM-RE metallic glasses, where x and y are composition concentrations of transition metal (TM) and rare earth (RE), respectively. Experimental results show that glass forming compositions with '6x+11y' near 100 have the smallest fragility parameter and best structure stability. In addition, '6x+11y' parameter has a positive relationship with onset-crystallization temperature, T x . Al-TM-RE glassy alloys with (6x+11y)≤100 undergo primary crystallization of fcc-Al nanocrystals, while alloys with (6x+11y)>100 exhibit nanoglassy or glassy crystallization behavior.

  14. Oxidation properties of laser clad Nb-Al alloys

    International Nuclear Information System (INIS)

    Tewari, S.K.; Mazumder, J.

    1992-01-01

    This paper reports on laser cladding parameters for non-equilibrium synthesis for several ternary and complex Nb-Al base alloys containing Ti, Cr, Si, Ni, B and C that have been established. Phase transformations occurring below 1500 degrees C have been determined using differential thermal analysis. Ductility of the clads is qualitatively evaluated from the extent of cracking around the microhardness indentations. Oxidation resistance of the clads in flowing air is measured at 800 degrees C, 1200 degrees C and 1400 degrees C and parabolic rate constants are calculated. Microstructure of the clads is studied using optical and scanning electron microscopes. X-ray diffraction and EDX techniques are used for identification of the oxides formed and the phases formed in as clad material. Oxide morphology is studied using SEM. Effect of alloying additions on the ductility and oxidation resistance of the laser clad Nb-Al alloys is discussed. The results are compared with those reported in literature for similar alloys produced by conventional processing methods

  15. Effect of cooling rate and Mg addition on the structural evaluation of rapidly solidified Al-20wt%Cu-12wt%Fe alloy

    Energy Technology Data Exchange (ETDEWEB)

    Karaköse, Ercan, E-mail: ekarakose@karatekin.edu.tr [Çankırı Karatekin University, Faculty of Sciences, Department of Physics, 18100 Çankırı (Turkey); Çolak, Hakan [Çankırı Karatekin University, Faculty of Sciences, Department of Chemistry, 18100 Çankırı (Turkey)

    2016-11-15

    The present work examines the effect of Mg contents and cooling rate on the morphology and mechanical properties of Al{sub 20}Cu{sub 12}Fe quasicrystalline alloy. The microstructure of the alloys was analyzed by scanning electron microscopy and the phase composition was identified by X-ray diffractometry. The melting characteristics were studied by differential thermal analysis under an Ar atmosphere. The mechanical features of the melt-spun and conventionally solidified alloys were tested by tensile-strength test and Vickers micro-hardness test. It was found that the final microstructure of the Al{sub 20}Cu{sub 12}Fe samples mainly depends on the cooling rate and Mg contents, which suggests that different cooling rates and Mg contents produce different microstructures and properties. The average grain sizes of the melt spun samples were about 100–300 nm at 35 m/s. The nanosize, dispersed, different shaped quasicrystal particles possessed a remarkable effect to the mechanical characteristics of the rapidly solidified ribbons. The microhardness values of the melt spun samples were approximately 18% higher than those of the conventionally counterparts. - Highlights: •Quasicrystal-creating materials have high potential for applications. •Different shaped nanosize quasicrystal particles were observed. •The addition of Mg has an important impact on the mechanical properties. •H{sub V} values of the MS0, MS3 and MS5 samples at 35 m/s were 8.56, 8.66 and 8.80 GPa. •The volume fraction of IQC increases with increasing cooling rates.

  16. Quasi-crystalline geometry for architectural structures

    DEFF Research Database (Denmark)

    Weizierl, Barbara; Wester, Ture

    2001-01-01

    Artikel på CD-Rom 8 sider. The quasi-crystal (QC) type of material was discovered in 1983 by Dan Schechtman from Technion, Haifa. This new crystalline structure of material broke totally with the traditional conception of crystals and geometry introducing non-periodic close packing of cells...... with fivefold symmetry in 3D space. The quasi-crystal geometry can be constructed from two different cubic cells with identical rhombic facets, where the relation between the diagonals is the golden section. All cells have identical rhombic faces, identical edges and identical icosahedral/dedecahedral nodes....... The purpose of the paper is to investigate some possibilities for the application of Quasi-Crystal geometry for structures in architecture. The basis for the investigations is A: to use the Golden Cubes (the two different hexahedra consisting of rhombic facets where the length of the diagonals has the Golden...

  17. Quasi-crystalline geometry for architectural structures

    DEFF Research Database (Denmark)

    Wester, Ture; Weinzieri, Barbara

    The quasi-crystal (QC) type of material was discovered in 1983 by Dan Schechtman from Technion, Haifa. This new crystalline structure of material broke totally with the traditional conception of crystals and geometry introducing non-periodic close packing of cells with fivefold symmetry in 3D space....... The quasi-crystal geometry can be constructed from two different cubic cells with identical rhombic facets, where the relation between the diagonals is the golden section. All cells have identical rhombic faces, identical edges and identical icosahedral/dodecahedral nodes....

  18. Low activation ferritic alloys

    Science.gov (United States)

    Gelles, David S.; Ghoniem, Nasr M.; Powell, Roger W.

    1986-01-01

    Low activation ferritic alloys, specifically bainitic and martensitic stainless steels, are described for use in the production of structural components for nuclear fusion reactors. They are designed specifically to achieve low activation characteristics suitable for efficient waste disposal. The alloys essentially exclude molybdenum, nickel, nitrogen and niobium. Strength is achieved by substituting vanadium, tungsten, and/or tantalum in place of the usual molybdenum content in such alloys.

  19. PLUTONIUM-ZIRCONIUM ALLOYS

    Science.gov (United States)

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

    1960-08-30

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

  20. Advances in titanium alloys

    International Nuclear Information System (INIS)

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

    1993-01-01

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

  1. Laser surface alloying of aluminium-transition metal alloys

    International Nuclear Information System (INIS)

    Almeida, A.; Vilar, R.

    1998-01-01

    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 high-strength 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-Mo and Al-Nb surface alloys by alloying Cr, Mo or Nb powder into an Al and 7175 Al alloy substrate using a CO 2 laser . This paper presents a review of the work that has been developed at Instituto Superior Tecnico on laser alloying of Al-TM alloy, over the last years. (Author) 16 refs

  2. Bulletin of Materials Science | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    We have investigated Fe substituted versions of the quasicrystalline (qc) alloy corresponding to Al65Cu20(Cr, Fe)15 with special reference to the possible occurrence of various quasicrystalline and related phases. Based on the explorations of various compositions it has been found that alloy compositions ...

  3. X-ray diffraction study on the microstructure of a Mg-Zn-Y alloy consolidated by high-pressure torsion

    Energy Technology Data Exchange (ETDEWEB)

    Jenei, Peter [Department of Materials Physics, Eoetvoes Lorand University, Budapest, P.O.B. 32, H-1518 (Hungary); Gubicza, Jeno, E-mail: gubicza@metal.elte.hu [Department of Materials Physics, Eoetvoes Lorand University, Budapest, P.O.B. 32, H-1518 (Hungary); Yoon, Eun Yoo; Kim, Hyoung Seop [Department of Materials Science and Engineering, POSTECH, Pohang 790-784 (Korea, Republic of)

    2012-10-25

    Highlights: Black-Right-Pointing-Pointer Mg{sub 95}Zn{sub 4.3}Y{sub 0.7} powder was consolidated by HPT at RT and 373 K. Black-Right-Pointing-Pointer The consolidated disks comprised ultrafine grains with high density of dislocations. Black-Right-Pointing-Pointer Quasicrystalline dispersoids strengthen the material by increasing the dislocation density. Black-Right-Pointing-Pointer Twinning in the Mg matrix was marginal during HPT. - Abstract: Mg{sub 95}Zn{sub 4.3}Y{sub 0.7} (at.%) alloy powder produced by an inert gas-atomizer was consolidated by high-pressure torsion (HPT) at room temperature and 373 K. The phase composition and the microstructure were investigated by X-ray diffraction and the microstructural parameters were correlated to the yield strength. HPT-processing yielded an ultrafine-grained microstructure with high dislocation density, leading to a large yield strength of the samples. Both the gas-atomized powder and the consolidated samples contained an icosahedral Mg{sub 3}YZn{sub 6} phase (I-phase) besides the main phase of {alpha}-Mg. It turned out that the I-phase dispersoids strengthen the consolidated material indirectly by increasing the dislocation density due to their pinning effect.

  4. High temperature niobium alloys

    International Nuclear Information System (INIS)

    Wojcik, C.C.

    1991-01-01

    Niobium alloys are currently being used in various high temperature applications such as rocket propulsion, turbine engines and lighting systems. This paper presents an overview of the various commercial niobium alloys, including basic manufacturing processes, properties and applications. Current activities for new applications include powder metallurgy, coating development and fabrication of advanced porous structures for lithium cooled heat pipes

  5. Shape memory alloys

    International Nuclear Information System (INIS)

    Kaszuwara, W.

    2004-01-01

    Shape memory alloys (SMA), when deformed, have the ability of returning, in certain circumstances, to their initial shape. Deformations related to this phenomenon are for polycrystals 1-8% and up to 15% for monocrystals. The deformation energy is in the range of 10 6 - 10 7 J/m 3 . The deformation is caused by martensitic transformation in the material. Shape memory alloys exhibit one directional or two directional shape memory effect as well as pseudoelastic effect. Shape change is activated by temperature change, which limits working frequency of SMA to 10 2 Hz. Other group of alloys exhibit magnetic shape memory effect. In these alloys martensitic transformation is triggered by magnetic field, thus their working frequency can be higher. Composites containing shape memory alloys can also be used as shape memory materials (applied in vibration damping devices). Another group of composite materials is called heterostructures, in which SMA alloys are incorporated in a form of thin layers The heterostructures can be used as microactuators in microelectromechanical systems (MEMS). Basic SMA comprise: Ni-Ti, Cu (Cu-Zn,Cu-Al, Cu-Sn) and Fe (Fe-Mn, Fe-Cr-Ni) alloys. Shape memory alloys find applications in such areas: automatics, safety and medical devices and many domestic appliances. Currently the most important appears to be research on magnetic shape memory materials and high temperature SMA. Vital from application point of view are composite materials especially those containing several intelligent materials. (author)

  6. Thermofluency in zirconium alloys

    International Nuclear Information System (INIS)

    Orozco M, E.A.

    1976-01-01

    A summary is presented about the theoretical and experimental results obtained at present in thermofluency under radiation in zirconium alloys. The phenomenon of thermofluency is presented in a general form, underlining the thermofluency at high temperature because this phenomenon is similar to the thermofluency under radiation, which ocurrs in zirconium alloys into the operating reactor. (author)

  7. Ductile transplutonium metal alloys

    Science.gov (United States)

    Conner, William V.

    1983-01-01

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

  8. Chemical sensitive interfacial free volume studies of nanophase Al-rich alloys

    International Nuclear Information System (INIS)

    Lechner, W.; Puff, W.; Wuerschum, R.; Wilde, G.

    2006-01-01

    Full text: Al-based nanocrystalline alloys have attracted substantial interest due to their outstanding mechanical properties. These alloys can be obtained by crystallization of melt-spun amorphous precursors or by grain refinement upon repeated cold-rolling of elemental layers. For both synthesis routes, the nanocrystallization process is sensitively affected by interfacial chemistry and free volumes. In order to contribute to an atomistic understanding of the interfacial structure and processes during nanocrystallization, the present work deals with studies of interfacial free volumes by means of positron-annihilation-spectroscopy. In addition to positron lifetime spectroscopy which yields information on the size of free volumes, coincident Doppler broadening of the positron-electron annihilation photons is applied as novel technique for studying the chemistry of interfaces in nanophase materials on an atomistic scale. Al-rich alloys of the above mentioned synthesis routes were studied in this work. (author)

  9. Causes and mechanisms of thermal embrittlement and corrosion cracking of complex α-titanium alloys

    International Nuclear Information System (INIS)

    Ushkov, S.S.; Rybin, V.V.; Razuvaeva, I.N.; Nesterova, E.V.; Gunbina, O.A.

    1995-01-01

    Effect of aging under 500 deg C on mechanical and corrosion-mechanical properties of Ti-6Al base titanium α-alloys with zirconium and carbon additions is studied. Using electron microscopy one determines the reasons of reduction of plasticity and of corrosion-mechanical strength of alloys after aging. It is determined that in the given alloys there are two different processes with occurrence different kinetics: the first one-formation of grain-boundary precipitations of Ti 2 (Fe, Ni) intermetallic compound responsible for plasticity reduction; and the second one-homogeneous decomposition of Ti-Al solid solution responsible for reduction of corrosion-mechanical properties. 14 refs., 6 figs

  10. Structure and mechanical properties of Al-3Fe rapidly solidified alloy

    International Nuclear Information System (INIS)

    Karakoese, Ercan; Keskin, Mustafa

    2011-01-01

    The Al based Al-3 wt%Fe alloy was prepared by conventionally casting (ingot) and further processed the melt-spinning technique and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) together with energy dispersive spectroscopy (EDS), differential scanning calorimetry (DSC) and the Vickers microhardness tester. The rapidly solidified (RS) binary alloys were composed of supersaturated α-Al solid solution and finely dispersed intermetallic phases. Experimental results showed that the mechanical properties of RS alloys were enhanced, which can be attributed to significant changes in the microstructure. The dependence of microhardness H V on the solidification rate (V) was analysed. These results showed that with the increasing values of V, the values of H V increased.

  11. Ultrahigh temperature intermetallic alloys

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-12-01

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

  12. Neutron-absorbing alloys

    International Nuclear Information System (INIS)

    Portnoi, K.I.; Arabei, L.B.; Gryaznov, G.M.; Levi, L.I.; Lunin, G.L.; Kozhukhov, V.M.; Markov, J.M.; Fedotov, M.E.

    1975-01-01

    A process is described for the production of an alloy consiting of 1 to 20% In, 0.5 to 15% Sm, and from 3 to 18% Hf, the balance being Ni. Such alloys show a good absorption capacity for thermal and intermediate neutrons, good neutron capture efficiency, and good corrosion resistance, and find application in nuclear reactor automatic control and safety systems. The Hf provides for the maintenance of a reasonably high order of neutron capture efficiency throughout the lifetime of a reactor. The alloys are formed in a vacuum furnace operating with an inert gas atmosphere at 280 to 300 mm.Hg. They have a corrosion resistance from 3 to 3.5 times that of the Ag-based alloys commonly employed, and a neutron capture efficiency about twice that of the Ag alloys. Castability and structural strength are good. (U.K.)

  13. Theoretical prediction of the electronic transport properties of the Al-Cu alloys based on the first-principle calculation and Boltzmann transport equation

    Science.gov (United States)

    Choi, Garam; Lee, Won Bo

    Metal alloys, especially Al-based, are commonly-used materials for various industrial applications. In this paper, the Al-Cu alloys with varying the Al-Cu ratio were investigated based on the first-principle calculation using density functional theory. And the electronic transport properties of the Al-Cu alloys were carried out using Boltzmann transport theory. From the results, the transport properties decrease with Cu-containing ratio at the temperature from moderate to high, but with non-linearity. It is inferred by various scattering effects from the calculation results with relaxation time approximation. For the Al-Cu alloy system, where it is hard to find the reliable experimental data for various alloys, it supports understanding and expectation for the thermal electrical properties from the theoretical prediction. Theoretical and computational soft matters laboratory.

  14. Alloying principles for magnesium base heat resisting alloys

    International Nuclear Information System (INIS)

    Drits, M.E.; Rokhlin, L.L.; Oreshkina, A.A.; Nikitina, N.I.

    1982-01-01

    Some binary systems of magnesium-base alloys in which solid solutions are formed, are considered for prospecting heat resistant alloys. It is shown that elements having essential solubility in solid magnesium strongly decreasing with temperature should be used for alloying maqnesium base alloys with high strength properties at increased temperatures. The strengthening phases in these alloys should comprise essential quantity of magnesium and be rather refractory

  15. Physical metallurgy of titanium alloys

    International Nuclear Information System (INIS)

    Collings, E.W.

    1988-01-01

    Researches in electric, magnetic, thermophysical properties of titanium alloys in the wide range of temperatures (from helium upto elevated one), as well as stability of phases in alloys of different types are generalized. Fundamental description of physical properties of binary model alloys is given. Acoustic emission, shape memory and Bauschinger effects, pseudoelasticity, aging and other aspects of physical metallurgy of titanium alloys are considered

  16. Co2FeAl based magnetic tunnel junctions with BaO and MgO/BaO barriers

    Directory of Open Access Journals (Sweden)

    J. Rogge

    2015-07-01

    Full Text Available We succeed to integrate BaO as a tunneling barrier into Co2FeAl based magnetic tunnel junctions (MTJs. By means of Auger electron spectroscopy it could be proven that the applied annealing temperatures during BaO deposition and afterwards do not cause any diffusion of Ba neither into the lower Heusler compound lead nor into the upper Fe counter electrode. Nevertheless, a negative tunnel magnetoresistance (TMR ratio of -10% is found for Co2FeAl (24 nm / BaO (5 nm / Fe (7 nm MTJs, which can be attributed to the preparation procedure and can be explained by the formation of Co- and Fe-oxides at the interfaces between the Heusler and the crystalline BaO barrier by comparing with theory. Although an amorphous structure of the BaO barrier seems to be confirmed by high-resolution transmission electron microscopy (TEM, it cannot entirely be ruled out that this is an artifact of TEM sample preparation due to the sensitivity of BaO to moisture. By replacing the BaO tunneling barrier with an MgO/BaO double layer barrier, the electric stability could effectively be increased by a factor of five. The resulting TMR effect is found to be about +20% at room temperature, although a fully antiparallel state has not been realized.

  17. The structure-directed effect of Al-based metal–organic frameworks on fabrication of alumina by thermal treatment

    International Nuclear Information System (INIS)

    Liu, Dandan; Dai, Fangna; Tang, Zhe; Liu, Yunqi; Liu, Chenguang

    2015-01-01

    Highlights: • We use Al-MOFs as precursor in the fabrication process of mesoporous alumina by thermal treatment. • The obtained mesoporous alumina has dual pore system and five-fold aluminum. • The aluminum building units in the precursor show structure-directed effect on the formation of alumina. - Abstract: In this work, the block-shaped Al-based metal–organic frameworks (Al-MOFs) MIL-53 have been synthesized by hydrothermal method. To detect the correlation between the structure of Al-MOFs and the formation of alumina, the ligands are eliminated by thermal treatment. MIL-53 and the calcination products were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), transmission electron microscopy (TEM), nitrogen adsorption–desorption and solid-state 27 Al nuclear magnetic resonance ( 27 Al NMR). It was found that after calcination, the block-shaped Al-MOFs precursor turns into high-crystallinity mesoporous alumina nanosheets, and the thermal treatment product γ-alumina possesses a dual pore system and a large surface area (146 m 2 /g), with five-fold aluminum. During the thermal treatment process, the structure of MIL-53 and its secondary building units have structure-directed effect in the formation of alumina

  18. Structural high-temperature and (βNiAl+γ)-alloys based on Ni-Al-Co-Me systems with an improved low-temperature ductility

    International Nuclear Information System (INIS)

    Povarova, K.B.; Kazanskaya, N.K.; Drozdov, A.A.; Lomberg, B.S.; Gerasimov, V.V.

    2001-01-01

    The βNiAl-based alloys (B2) have lower density higher resistance to oxidation, and higher melting temperature relative to those of Ni-superalloys or γ'Ni 3 Al-base alloys. An improved low-temperature ductility of advanced Ni-AI-Co-M β+γ alloys(El=9-16 % at 293-1173 K is achieved due to the formation γ-Ni solid solution intergranular interlayers of eutectic origin. Secondary γ and/or γ' precipitates form in the grains of the supersaturated β-solid solution upon heat treatment at 1473-1573 K and 1073-1173 K. The limiting contents of alloying elements (Ti, Hf, Nb, Ta, Cr, Mo) for the (β+γ) alloys Ni - (19-29) % AI - (22-35) % Co, are determined which allowed to avoid the formation of primary γ'-phase (decrease solidus temperature ≤1643 K) and hard phases of the types σ, η and δ (decrease ductility). Alloying affects the morphology of the secondary γ and γ' precipitates: globular equiaxed precipitates are formed in the alloys containing Cr, Mo, and needle precipitates are formed in alloys alloys containing γ'-forming elements Nb, Ta and, especially, Ti and Hf. After directional solidification, (β+γ')-alloys have directed columnar special structure with a low extension of transverse grain boundaries. This microstructure allows one to increase UTS, by a factor 1,5-2 and long-term strength (time to rupture increase by a factor of 5-10 at 1173 K). (author)

  19. The free growth criterion for grain initiation in TiB 2 inoculated γ-titanium aluminide based alloys

    Science.gov (United States)

    Gosslar, D.; Günther, R.

    2014-02-01

    γ-titanium aluminide (γ-TiAl) based alloys enable for the design of light-weight and high-temperature resistant engine components. This work centers on a numerical study of the condition for grain initiation during solidification of TiB2 inoculated γ-TiAl based alloys. Grain initiation is treated according to the so-called free growth criterion. This means that the free growth barrier for grain initiation is determined by the maximum interfacial mean curvature between a nucleus and the melt. The strategy presented in this paper relies on iteratively increasing the volume of a nucleus, which partially wets a hexagonal TiB2 crystal, minimizing the interfacial energy and calculating the corresponding interfacial curvature. The hereby obtained maximum curvature yields a scaling relation between the size of TiB2 crystals and the free growth barrier. Comparison to a prototypical TiB2 crystal in an as cast γ-TiAl based alloy allowed then to predict the free growth barrier prevailing under experimental conditions. The validity of the free growth criterion is discussed by an interfacial energy criterion.

  20. Fabrication of Al-based composites reinforced with in situ devitrified Al{sub 84}Ni{sub 8.4}Y{sub 4.8}La{sub 1.8}Co{sub 1} particles by hot pressing consolidation

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Qing, E-mail: buaayq00@gmail.com; Zhang, Yitan; Zhang, Haiping; Zheng, Ruixiao; Xiao, Wenlong; Ma, Chaoli, E-mail: machaoli@buaa.edu.cn

    2015-11-05

    In this study, Al{sub 84}Ni{sub 8.4}Y{sub 4.8}La{sub 1.8}Co{sub 1} particles reinforced Al-based composites were prepared by hot pressing sintering and subsequent hot extrusion. The glassy powders were produced by gas atomization and then employed to mechanical milling. After hot pressing sintering, the nano-scale intermetallic compounds precipitated from metallic glass matrix due to higher temperature than super-cooled liquid region. The mechanical properties of 2024 alloy were improved by addition of glassy particles. The ultimate compressive stress increased from 482 MPa for 2024 alloy to 545 MPa, 627 MPa and 735 MPa for composites with 20 w.t.% 40 w.t.% and 60 w.t.% glassy powders addition, respectively, together with considerable fracture strain ranging between 2.9% and 13.6%. And the mechanical properties could be predicted by using the Rule of Mixture, which predicts the mechanical properties of the bulks from the volume weighed average of the constituent properties. - Highlights: • The composites are fabricate by hot pressing and extrusion. • The single phase of amorphous alloy is obtained by sieving. • The nano-scale compounds precipitates from glassy matrix. • The compressive strength reaches to the value of 735 MPa. • The strength can fit well with rule of mixture.

  1. Technetium and technetium alloys

    International Nuclear Information System (INIS)

    Ijdo, W.L.

    1993-10-01

    This report presents the results of a literature survey on technetium and technetium alloys. The literature has been searched through 1993. The survey was focused on technetium and (binary cubic) technetium alloys, but other important information on technetium has not been omitted from this survey. This report has been written with the aim to collect more information about phase systems which could be of importance in the transmutation process by neutrons of technetium. With the information presented in this report, it should be possible to select a suitable technetium alloy for further investigation regarding to the transmutation process. (orig.)

  2. Positrons in amorphous alloys

    International Nuclear Information System (INIS)

    Moser, Pierre.

    1981-07-01

    Positron annihilation techniques give interesting informations about ''empty spaces'' in amorphous alloys. The results of an extensive research work on the properties of either pre-existing or irradiation induced ''empty spaces'' in four amorphous alloys are presented. The pre-existing empty spaces appear to be small vacancy-like defects. The irradiation induced defects are ''close pairs'' with widely distributed configurations. There is a strong interaction between vacancy like and interstitial like components. A model is proposed, which explains the radiation resistance mechanism of the amorphous alloys. An extensive joint research work to study four amorphous alloys, Fe 80 B 20 ,Fe 40 Ni 40 P 14 B 6 , Cu 50 Ti 50 , Pd 80 Si 20 , is summarized

  3. Electroplating on titanium alloy

    Science.gov (United States)

    Lowery, J. R.

    1971-01-01

    Activation process forms adherent electrodeposits of copper, nickel, and chromium on titanium alloy. Good adhesion of electroplated deposits is obtained by using acetic-hydrofluoric acid anodic activation process.

  4. Refractory alloy component fabrication

    International Nuclear Information System (INIS)

    Young, W.R.

    1984-01-01

    Purpose of this report is to describe joining procedures, primarily welding techniques, which were developed to construct reliable refractory alloy components and systems for advanced space power systems. Two systems, the Nb-1Zr Brayton Cycle Heat Receiver and the T-111 Alloy Potassium Boiler Development Program, are used to illustrate typical systems and components. Particular emphasis is given to specific problems which were eliminated during the development efforts. Finally, some thoughts on application of more recent joining technology are presented. 78 figures

  5. Machining of titanium alloys

    CERN Document Server

    2014-01-01

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

  6. Microstructure and wear characteristics on Al alloy matrix composite reinforced with Ni perform

    Energy Technology Data Exchange (ETDEWEB)

    Park, Won Jo; Park, Cheol Hong; Kim, Hyung Jin; Huh, Sun Chul [Gyeongsang National University, Tongyeong, (Korea, Republic of)

    2012-06-15

    Al based composite reinforced with Nickel is used for diesel engine piston, because the thermal properties, strength and corrosion resistant are for better than Al alloy alone. For processing, the intermetallic compounds of Ni and Al improves wear resistance due to its high hardness. Existing process methods for MMC (metal matrix composite) using preform were manufactured under high-pressure. However, this causes deformation of the preform or weaknesses in the completed MMC. Low-pressure infiltration can prevent these problems, and there is an advantage of cost reduction in of production with small-scale of production equipment. In this study, the microstructure and wear characteristics of Al-based composite with Ni preform as reinforcement with low-pressure infiltration was analyzed.

  7. Electroplating technologies of alloys

    International Nuclear Information System (INIS)

    Kim, Joung Soo; Kim, Seung Ho; Jeong, Hyun Kyu; Hwnag, Sung Sik; Seo, Yong Chil; Kim, Dong Jin; Seo, Moo Hong

    2001-12-01

    In localization of electrosleeving technique, there are some problems like the following articles. Firstly, Patents published by OHT have claimed Ni-P, Ni-B alloy plating and Mo, Mn Cr, W, Co as a pinning agent. Secondly, alloy platings have many restrictions. There are some method to get alloy plating in spite of the various restrictions. If current density increase above limiting current density in one of the metals, both of the metals discharge at the same time. The addition of surface active agent(sufactant) in the plating solution is one of the methods to get alloy plating. Alloy plating using pulse current easily controls chemical composition and structure of deposit. Ni-Fe alloy plating is known to exhibit anomalous type of plating behavior in which deposition of the less noble metal is favoured. Presence of hypophohphite ion can control the iron codeposition by changing the deposition mechanism. Hypophohphite suppresses the deposition of Fe and also promotes Ni. Composite plating will be considered to improve the strength at the high temperature. Addition of particle size of 10δ400μm makes residual stress compressive in plate layer and suppress the grain growth rate at the high temperature. Addition of particle makes suface roughness high and fracture stress low at high temperature. But, selection of the kinds of particle and control of additives amount overcome the problems above

  8. Texture in low-alloyed uranium alloys

    International Nuclear Information System (INIS)

    Sariel, J.

    1982-08-01

    The dependence of the preferred orientation of cast and heat-treated polycrystalline adjusted uranium and uranium -0.1 w/o chromium alloys on the production process was studied. The importance of obtaining material free of preferred orientation is explained, and a survey of the regular methods to determine preferred orientation is given. Dilatometry, tensile testing and x-ray diffraction were used to determine the extent of the directionality of these alloys. Data processing showed that these methods are insufficient in a case of a material without any plastic forming, because of unreproducibility of results. Two parameters are defined from the results of Schlz's method diffraction test. These parameters are shown theoretically and experimentally (by extreme-case samples) to give the deviation from isotropy. Application of these parameters to the examined samples showes that cast material has preferred orientation, though it is not systematic. This preferred orientation was reduced by adequate heat treatments

  9. WC-3015 alloy (high-temperature alloy)

    International Nuclear Information System (INIS)

    Anon.

    1974-01-01

    WC-3015 Nb alloy containing 28 to 30 Hf, 1 to 2 Zr, 13 to 16 W, 0 to 4 Ta, 0 to 5 Ti, 0.07 to 0.33 C, less than or equal to 0.02 N, less than or equal to 0.03 O, less than or equal to 0.001 H was developed for use at high temperature in oxidizing environments. Its composition can be tailored to meet specific requirements. When WC-3015 is exposed to O at elevated temperature, Hf and Nb oxidized preferentially and HfO 2 dissolves in Nb 2 O 5 to form 6HfO-Nb 2 O 5 . This complex oxide has a tight cubic lattice which resists the diffusion of O into the substrate. During 24-h exposure to air at 2400 0 F, the alloy oxidizes to a depth of approximately 0.035 in. with a surface recession of 0 to 0.004 in. Oxidation resistance of WC-3015 welds and base material can be further enhanced greatly by applying silicide coatings. WC-3015 alloy can be machined by conventional and electrical-discharge methods. It can be hot worked readily by extrusion, forging or rolling. Cold working can be used at room or elevated temperature. It can be welded by the electron-beam or Tig processes. Physical constants, typical mechanical properties at 75 to 2400 0 F, and effects of composition and heat treatment on tensile and stress-rupture properties of the alloy are tabulated

  10. A composite of complex and chemical hydrides yields the first Al-based amidoborane with improved hydrogen storage properties.

    Science.gov (United States)

    Dovgaliuk, Iurii; Jepsen, Lars H; Safin, Damir A; Łodziana, Zbigniew; Dyadkin, Vadim; Jensen, Torben R; Devillers, Michel; Filinchuk, Yaroslav

    2015-10-05

    The first Al-based amidoborane Na[Al(NH2 BH3 )4 ] was obtained through a mechanochemical treatment of the NaAlH4 -4 AB (AB=NH3 BH3 ) composite releasing 4.5 wt % of pure hydrogen. The same amidoborane was also produced upon heating the composite at 70 °C. The crystal structure of Na[Al(NH2 BH3 )4 ], elucidated from synchrotron X-ray powder diffraction and confirmed by DFT calculations, contains the previously unknown tetrahedral ion [Al(NH2 BH3 )4 ](-) , with every NH2 BH3 (-) ligand coordinated to aluminum through nitrogen atoms. Combination of complex and chemical hydrides in the same compound was possible due to both the lower stability of the AlH bonds compared to the BH ones in borohydride, and due to the strong Lewis acidity of Al(3+) . According to the thermogravimetric analysis-differential scanning calorimetry-mass spectrometry (TGA-DSC-MS) studies, Na[Al(NH2 BH3 )4 ] releases in two steps 9 wt % of pure hydrogen. As a result of this decomposition, which was also supported by volumetric studies, the formation of NaBH4 and amorphous product(s) of the surmised composition AlN4 B3 H(0-3.6) were observed. Furthermore, volumetric experiments have also shown that the final residue can reversibly absorb about 27 % of the released hydrogen at 250 °C and p(H2 )=150 bar. Hydrogen re-absorption does not regenerate neither Na[Al(NH2 BH3 )4 ] nor starting materials, NaAlH4 and AB, but rather occurs within amorphous product(s). Detailed studies of the latter one(s) can open an avenue for a new family of reversible hydrogen storage materials. Finally, the NaAlH4 -4 AB composite might become a starting point towards a new series of aluminum-based tetraamidoboranes with improved hydrogen storage properties such as hydrogen storage density, hydrogen purity, and reversibility. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Aluminum fin-stock alloys

    International Nuclear Information System (INIS)

    Gul, R.M.; Mutasher, F.

    2007-01-01

    Aluminum alloys have long been used in the production of heat exchanger fins. The comparative properties of the different alloys used for this purpose has not been an issue in the past, because of the significant thickness of the finstock material. However, in order to make fins lighter in weight, there is a growing demand for thinner finstock materials, which has emphasized the need for improved mechanical properties, thermal conductivity and corrosion resistance. The objective of this project is to determine the effect of iron, silicon and manganese percentage increment on the required mechanical properties for this application by analyzing four different aluminum alloys. The four selected aluminum alloys are 1100, 8011, 8079 and 8150, which are wrought non-heat treatable alloys with different amount of the above elements. Aluminum alloy 1100 serve as a control specimen, as it is commercially pure aluminum. The study also reports the effect of different annealing cycles on the mechanical properties of the selected alloys. Metallographic examination was also preformed to study the effect of annealing on the precipitate phases and the distribution of these phases for each alloy. The microstructure analysis of the aluminum alloys studied indicates that the precipitated phase in the case of aluminum alloys 1100 and 8079 is beta-FeAI3, while in 8011 it is a-alfa AIFeSi, and the aluminum alloy 8150 contains AI6(Mn,Fe) phase. The comparison of aluminum alloys 8011 and 8079 with aluminum alloy 1100 show that the addition of iron and silicon improves the percent elongation and reduces strength. The manganese addition increases the stability of mechanical properties along the annealing range as shown by the comparison of aluminum alloy 8150 with aluminum alloy 1100. Alloy 8150 show superior properties over the other alloys due to the reaction of iron and manganese, resulting in a preferable response to thermal treatment and improved mechanical properties. (author)

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

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  13. Preparation, microstructure and thermal properties of Mg−Bi alloys as phase change materials for thermal energy storage

    International Nuclear Information System (INIS)

    Fang, Dong; Sun, Zheng; Li, Yuanyuan; Cheng, Xiaomin

    2016-01-01

    Highlights: • The microstructure and thermal properties of Mg−Bi alloys are determined. • The relationship between melting enthalpies and phase composition are studied. • The activation energy of Mg−54%Bi alloy is calculated by multiple DSC technology. • Mg−54%Bi alloy is proposed as a phase change material at high (>420 °C) temperature. - Abstract: Comparing with Al-based phase change material, Mg-based phase change material is getting more and more attention due to its high corrosion resistance with encapsulation materials based on iron. This study focuses on the characterization of Mg−36%Bi, Mg−54%Bi and Mg−60%Bi (wt. %) alloys as phase change materials for thermal energy storage at high temperature. The phase compositions, microstructure and phase change temperatures were investigated by X-ray diffusion (XRD), electron probe micro-analysis (EPMA) and differential scanning calorimeter (DSC) analysis, respectively. The results indicates that the microstructure of Mg−36%Bi and Mg−54%Bi alloys are mainly composed of α-Mg matrix and α-Mg + Mg_3Bi_2 eutectic phases, Mg−60%Bi alloy are mainly composed of the Mg_3Bi_2 phase and α-MgMg_3Bi_2 eutectic phases. The melting enthalpies of Mg−36%Bi, Mg−54%Bi and Mg−60%Bi alloys are 138.2, 180.5 and 48.7 J/g, with the phase change temperatures of 547.6, 546.3 and 548.1 °C, respectively. The Mg−54%Bi alloy has the highest melting enthalpy in three alloys. The main reason may be that it has more proportion of α-Mg + Mg_3Bi_2 eutectic phases. The thermal expansion of three alloys increases with increasing temperature. The values of the thermal conductivity decrease with increasing Bi content. Besides, the activation energy of Mg−54%Bi was calculated by multiple DSC technology.

  14. Effects of gas to melt ratio on the microstructure of an Al–10.83Zn–3.39Mg–1.22Cu alloy produced by spray atomization and deposition

    Energy Technology Data Exchange (ETDEWEB)

    Guo, S. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Center of Analysis Measurement, Harbin Institute of Technology, Harbin 150001 (China); Ning, Z.L. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); National Key laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001 (China); Zhang, M.X. [School of Mechanical and Mining Engineering, The University of Queensland, St Lucia, QLD 4072 (Australia); Cao, F.Y. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); National Key laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001 (China); Sun, J.F., E-mail: jfsun@hit.edu.cn [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); National Key laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001 (China)

    2014-01-15

    Various gas to melt ratios (GMR) that govern the cooling rate of spray forming can be achieved through controlling the atomizer form and the atomization pressure. The effect of the GMR on microstructures of an Al–10.83Zn–3.39Mg–1.22Cu alloy produced through spray forming has been studied using electron microscopy. When the GMR is high at 3.5, dendritic structure and quasi-crystalline i-Mg{sub 32}(AlZn){sub 49} particles inherited from the original powders can be observed. Spray forming at medium GMR of 2.3 produces equiaxed α-Al grains and MgZn{sub 2} phase that discontinuously distributes along the grain boundaries and within the grains as small particles. The low GMR of 1.4 corresponds to low cooling rate. Coarse and equiaxed α-Al grains together with eutectic structure consisting of b.c.c.-Mg{sub 32}(AlZn){sub 49} and α-Al phases along the grain boundaries are obtained. - Highlights: • At high GMR, the broken fragments and i-Mg{sub 32}(AlZn){sub 49} quasicrystal are observed. • At medium GMR, microstructure consists of α-Al equiaxed grains and MgZn{sub 2} phase. • At low GMR, the coarsened α-Al grains and bcc-Mg{sub 32}(AlZn){sub 49} eutectic appear.

  15. Progress on Numerical Modeling of the Dispersion of Ceramic Nanoparticles During Ultrasonic Processing and Solidification of Al-Based Nanocomposites

    Science.gov (United States)

    Zhang, Daojie; Nastac, Laurentiu

    2016-12-01

    In present study, 6061- and A356-based nano-composites are fabricated by using the ultrasonic stirring technology (UST) in a coreless induction furnace. SiC nanoparticles are used as the reinforcement. Nanoparticles are added into the molten metal and then dispersed by ultrasonic cavitation and acoustic streaming assisted by electromagnetic stirring. The applied UST parameters in the current experiments are used to validate a recently developed magneto-hydro-dynamics (MHD) model, which is capable of modeling the cavitation and nanoparticle dispersion during UST processing. The MHD model accounts for turbulent fluid flow, heat transfer and solidification, and electromagnetic field, as well as the complex interaction between the nanoparticles and both the molten and solidified alloys by using ANSYS Maxwell and ANSYS Fluent. Molecular dynamics (MD) simulations are conducted to analyze the complex interactions between the nanoparticle and the liquid/solid interface. The current modeling results demonstrate that a strong flow can disperse the nanoparticles relatively well during molten metal and solidification processes. MD simulation results prove that ultrafine particles (10 nm) will be engulfed by the solidification front instead of being pushed, which is beneficial for nano-dispersion.

  16. INVESTIGATION OF MAGNESIUM ALLOYS MACHINABILITY

    Directory of Open Access Journals (Sweden)

    Berat Barıs BULDUM

    2013-01-01

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

  17. Structural thermodynamics of alloys

    CERN Document Server

    Manenc, Jack

    1973-01-01

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

  18. De-alloyed platinum nanoparticles

    Science.gov (United States)

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

    2011-08-09

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

  19. Welding of refractory alloys

    International Nuclear Information System (INIS)

    Lessmann, G.G.

    1984-01-01

    This review primarily summarizes welding evaluations supported by NASA-Lewis Research Center in the 1960s. A literature search run in preparation for this review indicates that more recent work is modest by comparison. Hence, this review restates these accomplishments briefly and addresses opportunities which have evolved in welding technology (such as lasers) in the intervening decade. Emphasis in this review is given to tantalum- and niobium-base alloys. Considerable work was also done to assure that a consistent comparison was made with tungsten. A wide variety of candidate alloys derived primarily from developments directed at aircraft propulsion applications were available. Early efforts by NASA were directed at screening studies to select promising structural alloys for the space power application. This objective required fine tuning of welding procedures, e.g., the demonstration of stringent standards for control of welding atmosphere to assure good corrosion resistance in liquid alkali metals. 16 figures, 6 tables

  20. Alloys under irradiation

    International Nuclear Information System (INIS)

    Martin, G.; Bellon, P.; Soisson, F.

    1997-01-01

    During the last two decades, some effort has been devoted to establishing a phenomenology for alloys under irradiation. Theoretically, the effects of the defect supersaturation, sustained defect fluxes and ballistic mixing on solid solubility under irradiation can now be formulated in a unified manner, at least for the most simple cases: coherent phase transformations and nearest-neighbor ballistic jumps. Even under such restrictive conditions, several intriguing features documented experimentally can be rationalized, sometimes in a quantitative manner and simple qualitative rules for alloy stability as a function of irradiation conditions can be formulated. A quasi-thermodynamic formalism can be proposed for alloys under irradiation. However, this point of view has limits illustrated by recent computer simulations. (orig.)

  1. Nickel base alloys

    International Nuclear Information System (INIS)

    Gibson, R.C.; Korenko, M.K.

    1980-01-01

    Nickel based alloy, the characteristic of which is that it mainly includes in percentages by weight: 57-63 Ni, 7-18 Cr, 10-20 Fe, 4-6 Mo, 1-2 Nb, 0.2-0.8 Si, 0.01-0.05 Zr, 1.0-2.5 Ti, 1.0-2.5 Al, 0.02-0.06 C and 0.002-0.015 B. The aim is to create new nickel-chromium alloys, hardened in a solid solution and by precipitation, that are stable, exhibit reduced swelling and resistant to plastic deformation inside the reactor. These alloys of the gamma prime type have improved mechanical strengthm swelling resistance, structural stability and welding properties compared with Inconel 625 [fr

  2. Hydrogen in titanium alloys

    International Nuclear Information System (INIS)

    Wille, G.W.; Davis, J.W.

    1981-04-01

    The titanium alloys that offer properties worthy of consideration for fusion reactors are Ti-6Al-4V, Ti-6Al-2Sn-4Zr-2Mo-Si (Ti-6242S) and Ti-5Al-6Sn-2Zr-1Mo-Si (Ti-5621S). The Ti-6242S and Ti-5621S are being considered because of their high creep resistance at elevated temperatures of 500 0 C. Also, irradiation tests on these alloys have shown irradiation creep properties comparable to 20% cold worked 316 stainless steel. These alloys would be susceptible to slow strain rate embrittlement if sufficient hydrogen concentrations are obtained. Concentrations greater than 250 to 500 wppm hydrogen and temperatures lower than 100 to 150 0 C are approximate threshold conditions for detrimental effects on tensile properties. Indications are that at the elevated temperature - low hydrogen pressure conditions of the reactors, there would be negligible hydrogen embrittlement

  3. The effect of TiB2 reinforcement on the mechanical properties of an Al-Cu-Li alloy-based metal-matrix composite

    Science.gov (United States)

    Langan, T. J.; Pickens, J. R.

    1991-01-01

    Weldalite 049, an Al-base Cu-Li-Mg-Ag-Zr alloy, achieves 700 MPa tensile strengths in the near-peak-aged temper in virtue of the nucleation of a T(1)-type platelike strengthening precipitate. Attention is presently given to the possibility that the alloy's modulus could be further increased through the addition of high-modulus TiB2 particles, using the 'XD' process, due to TiB2's good wettability with liquid Al. An 8-percent modulus increase is obtained with 4 vol pct TiB2.

  4. Evaluation of thermophysical properties of Al–Sn–Si alloys based on computational thermodynamics and validation by numerical and experimental simulation of solidification

    International Nuclear Information System (INIS)

    Bertelli, Felipe; Cheung, Noé; Ferreira, Ivaldo L.; Garcia, Amauri

    2016-01-01

    Highlights: • A numerical routine coupled to a computational thermodynamics software is proposed to calculate thermophysical properties. • The approach encompasses numerical and experimental simulation of solidification. • Al–Sn–Si alloys thermophysical properties are validated by experimental/numerical cooling rate results. - Abstract: Modelling of manufacturing processes of multicomponent Al-based alloys products, such as casting, requires thermophysical properties that are rarely found in the literature. It is extremely important to use reliable values of such properties, as they can influence critically on simulated output results. In the present study, a numerical routine is developed and connected in real runtime execution to a computational thermodynamic software with a view to permitting thermophysical properties such as: latent heats; specific heats; temperatures and heats of transformation; phase fractions and composition and density of Al–Sn–Si alloys as a function of temperature, to be determined. A numerical solidification model is used to run solidification simulations of ternary Al-based alloys using the appropriate calculated thermophysical properties. Directional solidification experiments are carried out with two Al–Sn–Si alloys compositions to provide experimental cooling rates profiles along the length of the castings, which are compared with numerical simulations in order to validate the calculated thermophysical data. For both cases a good agreement can be observed, indicating the relevance of applicability of the proposed approach.

  5. The application of computational thermodynamics and a numerical model for the determination of surface tension and Gibbs-Thomson coefficient of aluminum based alloys

    International Nuclear Information System (INIS)

    Jacome, Paulo A.D.; Landim, Mariana C.; Garcia, Amauri; Furtado, Alexandre F.; Ferreira, Ivaldo L.

    2011-01-01

    Highlights: → Surface tension and the Gibbs-Thomson coefficient are computed for Al-based alloys. → Butler's scheme and ThermoCalc are used to compute the thermophysical properties. → Predictive cell/dendrite growth models depend on accurate thermophysical properties. → Mechanical properties can be related to the microstructural cell/dendrite spacing. - Abstract: In this paper, a solution for Butler's formulation is presented permitting the surface tension and the Gibbs-Thomson coefficient of Al-based binary alloys to be determined. The importance of Gibbs-Thomson coefficient for binary alloys is related to the reliability of predictions furnished by predictive cellular and dendritic growth models and of numerical computations of solidification thermal variables, which will be strongly dependent on the thermophysical properties assumed for the calculations. A numerical model based on Powell hybrid algorithm and a finite difference Jacobian approximation was coupled to a specific interface of a computational thermodynamics software in order to assess the excess Gibbs energy of the liquid phase, permitting the surface tension and Gibbs-Thomson coefficient for Al-Fe, Al-Ni, Al-Cu and Al-Si hypoeutectic alloys to be calculated. The computed results are presented as a function of the alloy composition.

  6. The application of computational thermodynamics and a numerical model for the determination of surface tension and Gibbs-Thomson coefficient of aluminum based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Jacome, Paulo A.D.; Landim, Mariana C. [Department of Mechanical Engineering, Fluminense Federal University, Av. dos Trabalhadores, 420-27255-125 Volta Redonda, RJ (Brazil); Garcia, Amauri, E-mail: amaurig@fem.unicamp.br [Department of Materials Engineering, University of Campinas, UNICAMP, PO Box 6122, 13083-970 Campinas, SP (Brazil); Furtado, Alexandre F.; Ferreira, Ivaldo L. [Department of Mechanical Engineering, Fluminense Federal University, Av. dos Trabalhadores, 420-27255-125 Volta Redonda, RJ (Brazil)

    2011-08-20

    Highlights: {yields} Surface tension and the Gibbs-Thomson coefficient are computed for Al-based alloys. {yields} Butler's scheme and ThermoCalc are used to compute the thermophysical properties. {yields} Predictive cell/dendrite growth models depend on accurate thermophysical properties. {yields} Mechanical properties can be related to the microstructural cell/dendrite spacing. - Abstract: In this paper, a solution for Butler's formulation is presented permitting the surface tension and the Gibbs-Thomson coefficient of Al-based binary alloys to be determined. The importance of Gibbs-Thomson coefficient for binary alloys is related to the reliability of predictions furnished by predictive cellular and dendritic growth models and of numerical computations of solidification thermal variables, which will be strongly dependent on the thermophysical properties assumed for the calculations. A numerical model based on Powell hybrid algorithm and a finite difference Jacobian approximation was coupled to a specific interface of a computational thermodynamics software in order to assess the excess Gibbs energy of the liquid phase, permitting the surface tension and Gibbs-Thomson coefficient for Al-Fe, Al-Ni, Al-Cu and Al-Si hypoeutectic alloys to be calculated. The computed results are presented as a function of the alloy composition.

  7. A Comparative Study on Permanent Mold Cast and Powder Thixoforming 6061 Aluminum Alloy and Sicp/6061Al Composite: Microstructures and Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Xuezheng Zhang

    2016-05-01

    Full Text Available Microstructural and mechanical characterization of 10 vol% SiC particles (SiCp reinforced 6061 Al-based composite fabricated by powder thixoforming (PTF was investigated in comparison with the PTF and permanent mold cast (PMC 6061 monolithic alloys. The results reveal that the microstructure of the PMC alloy consists of coarse and equiaxed α dendrites and interdendritic net-like eutectic phases. However, the microstructure of the PTF composite, similar to that of the PTF alloy, consists of near-spheroidal primary particles and intergranular secondarily solidified structures except SiCp, which are distributed in the secondarily solidified structures. The eutectics amount in the PTF materials is distinctly lower than that in the PMC alloy, and the microstructures of the former materials are quite compact while that of the latter alloy is porous. Therefore, the PTF alloy shows better tensile properties than the PMC alloy. Owing to the existence of the SiC reinforcing particles, the PTF composite attains an ultimate tensile strength and yield strength of 230 MPa and 128 MPa, representing an enhancement of 27.8% and 29.3% than those (180 MPa and 99 MPa of the PTF alloy. A modified model based on three strengthening mechanisms was proposed to calculate the yield strength of the PTF composite. The obtained theoretical results were quite consistent with the experimental data.

  8. A Comparative Study on Permanent Mold Cast and Powder Thixoforming 6061 Aluminum Alloy and Sicp/6061Al Composite: Microstructures and Mechanical Properties.

    Science.gov (United States)

    Zhang, Xuezheng; Chen, Tijun; Qin, He; Wang, Chong

    2016-05-24

    Microstructural and mechanical characterization of 10 vol% SiC particles (SiC p ) reinforced 6061 Al-based composite fabricated by powder thixoforming (PTF) was investigated in comparison with the PTF and permanent mold cast (PMC) 6061 monolithic alloys. The results reveal that the microstructure of the PMC alloy consists of coarse and equiaxed α dendrites and interdendritic net-like eutectic phases. However, the microstructure of the PTF composite, similar to that of the PTF alloy, consists of near-spheroidal primary particles and intergranular secondarily solidified structures except SiC p , which are distributed in the secondarily solidified structures. The eutectics amount in the PTF materials is distinctly lower than that in the PMC alloy, and the microstructures of the former materials are quite compact while that of the latter alloy is porous. Therefore, the PTF alloy shows better tensile properties than the PMC alloy. Owing to the existence of the SiC reinforcing particles, the PTF composite attains an ultimate tensile strength and yield strength of 230 MPa and 128 MPa, representing an enhancement of 27.8% and 29.3% than those (180 MPa and 99 MPa) of the PTF alloy. A modified model based on three strengthening mechanisms was proposed to calculate the yield strength of the PTF composite. The obtained theoretical results were quite consistent with the experimental data.

  9. Silumins alloy crystallization

    Directory of Open Access Journals (Sweden)

    S. Pietrowski

    2009-07-01

    Full Text Available This paper presents the results of research, by ATD method, of hypo-, near- and hyperutectic silumins crystallization containing the following alloying additives: Mg, Ni, Cu, Cr, Mo, W, V. It has been shown that, depending on their concentration may crystallize pre-eutectic or eutectic multicomponent phases containing these alloy additives. It has been revealed that any subsequent crystallizable phase nucleate and grows near the liquid/former crystallized phase interface. In multiphases compound also falls the silicon, resulting in a reduction in its quantity and the fragmentation in the eutectic mixture. As a result, it gets a high hardness of silumins in terms of 110-220HB.

  10. Shape memory effect alloys

    International Nuclear Information System (INIS)

    Koshimizu, S.

    1992-01-01

    Although the pseudo- or super-elasticity phenomena and the shape memory effect were known since the 1940's, the enormous curiosity and the great interest to their practical applications emerged with the development of the NITINOL alloy (Nickel-Titanium Naval Ordance Laboratory) by the NASA during the 1960's. This fact marked the appearance of a new class of materials, popularly known as shape memory effect alloys (SMEA). The objective of this work is to present a state-of-the-art of the development and applications for the SMEA. (E.O.)

  11. Tungsten Alloy Outgassing Measurements

    CERN Document Server

    Rutherfoord, John P; Shaver, L

    1999-01-01

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

  12. Galvanic corrosion in odontological alloys

    International Nuclear Information System (INIS)

    Riesgo, O.; Bianchi, G.L.; Duffo, G.S.

    1993-01-01

    Galvanic corrosion can occur when different alloys are placed in direct contact within the oral cavity or within tissues. Concern has been expressed associated with the coupling of selected restorative materials as well as implant material with various alloys used for restorative procedures. This could be critical if the crown or bridge had subgingival finish line with a metallic zone in contact with the tissue, and the implant was made in titanium alloy. The present work shows the results of galvanic coupling studies done on implants of titanium alloy connected to nickel-chromium and cobalt-chromium alloys. (Author)

  13. Borated aluminum alloy manufacturing technology

    International Nuclear Information System (INIS)

    Shimojo, Jun; Taniuchi, Hiroaki; Kajihara, Katsura; Aruga, Yasuhiro

    2003-01-01

    Borated aluminum alloy is used as the basket material of cask because of its light weight, thermal conductivity and superior neutron absorbing abilities. Kobe Steel has developed a unique manufacturing process for borated aluminum alloy using a vacuum induction melting method. In this process, aluminum alloy is melted and agitated at higher temperatures than common aluminum alloy fabrication methods. It is then cast into a mold in a vacuum atmosphere. The result is a high quality aluminum alloy which has a uniform boron distribution and no impurities. (author)

  14. Fracture of Shape Memory Alloys

    OpenAIRE

    Miyazaki, Shuichi; Otsuka, Kazuhiro

    1981-01-01

    The initiation and the propagation of cracks during both quenching and deformation in polycrystalline Cu-Al-Ni alloys have been investigated under various conditions. The fracture surfaces of Ti-Ni and Cu-Al-Ni alloys were also observed by a scanning electron microscope. From these results, it was concluded that the brittleness of Cu-Al-Ni alloy and other β phase alloys are due to large elastic anisotropy and large grain sizes, while that the large ductility in Ti-Ni alloy being due to the sm...

  15. High-resolution transmission electron microscopy of grain-refining particles in amorphous aluminum alloys

    International Nuclear Information System (INIS)

    Schumacher, P.; Greer, A.L.

    1996-01-01

    The nucleation mechanism of Al-Ti-B grain refiners is studied in an Al-based amorphous alloy. The ability to limit growth of α-Al in the amorphous alloy permits the microscopical observation of nucleation events on boride particles. Earlier studies of this kind are extended by using high-resolution electron microscopy. This shows that the efficient nucleation α-Al depends on the TiB 2 particles being coated with a thin layer of Al 3 Ti, which can form only when there is some excess titanium in the melt. The aluminide layer, stabilized by adsorption effects, can be as little as a few monolayers thick, and is coherent with the boride. The nature of this layer, and its importance for the nucleation mechanism are discussed. The fading of the grain refinement action is also considered

  16. Fragility of superheated melts and glass-forming ability in Pr-based alloys

    International Nuclear Information System (INIS)

    Meng, Q.G.; Zhou, J.K.; Zheng, H.X.; Li, J.G.

    2006-01-01

    The kinetic viscosity (η) of superheated melts, thermal properties (T x , T m , T L ) and X-ray diffraction analysis on the Pr-based bulk metallic glasses (BMG) are reported and discussed. A new refined concept, the superheated fragility defined as M' = E S δ x /k B , has been developed based on common solidification theory and the Arrhenius equation. The interrelationship between this kind of fragility and the glass-forming ability (GFA) is elaborated on and evaluated in Pr-based BMG and Al-based amorphous ribbon alloys. Using viscosity data of superheated melts, it is shown, theoretically and experimentally, that the fragility parameter M' may be used as a GFA indicator for metallic alloys

  17. High strength ferritic alloy

    International Nuclear Information System (INIS)

    1977-01-01

    A high strength ferritic steel is specified in which the major alloying elements are chromium and molybdenum, with smaller quantities of niobium, vanadium, silicon, manganese and carbon. The maximum swelling is specified for various irradiation conditions. Rupture strength is also specified. (U.K.)

  18. Ferromagnetic bulk glassy alloys

    International Nuclear Information System (INIS)

    Inoue, Akihisa; Makino, Akihiro; Mizushima, Takao

    2000-01-01

    This paper deals with the review on the formation, thermal stability and magnetic properties of the Fe-based bulk glassy alloys in as-cast bulk and melt-spun ribbon forms. A large supercooled liquid region over 50 K before crystallization was obtained in Fe-(Al, Ga)-(P, C, B, Si), Fe-(Cr, Mo, Nb)-(Al, Ga)-(P, C, B) and (Fe, Co, Ni)-Zr-M-B (M=Ti, Hf, V, Nb, Ta, Cr, Mo and W) systems and bulk glassy alloys were produced in a thickness range below 2 mm for the Fe-(Al, Ga)-(P, C, B, Si) system and 6 mm for the Fe-Co-(Zr, Nb, Ta)-(Mo, W)-B system by copper-mold casting. The ring-shaped glassy Fe-(Al, Ga)-(P, C, B, Si) alloys exhibit much better soft magnetic properties as compared with the ring-shaped alloy made from the melt-spun ribbon because of the formation of the unique domain structure. The good combination of high glass-forming ability and good soft magnetic properties indicates the possibility of future development as a new bulk glassy magnetic material

  19. Titanium and zirconium alloys

    International Nuclear Information System (INIS)

    Pinard Legry, G.

    1994-01-01

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

  20. Hardening of niobium alloys at precrystallization annealing

    International Nuclear Information System (INIS)

    Vasil'eva, E.V.; Pustovalov, V.A.

    1989-01-01

    Niobium base alloys were investigated. It is shown that precrystallization annealing of niobium-molybdenum, niobium-vanadium and niobium-zirconium alloys elevates much more sufficiently their resistance to microplastic strains, than to macroplastic strains. Hardening effect differs sufficiently for different alloys. The maximal hardening is observed for niobium-vanadium alloys, the minimal one - for niobium-zirconium alloys

  1. Investigation of the Precipitation Behavior in Aluminum Based Alloys

    KAUST Repository

    Khushaim, Muna S.

    2015-11-30

    The transportation industries are constantly striving to achieve minimum weight to cut fuel consumption and improve overall performance. Different innovative design strategies have been placed and directed toward weight saving combined with good mechanical behavior. Among different materials, aluminum-based alloys play a key role in modern engineering and are widely used in construction components because of their light weight and superior mechanical properties. Introduction of different nano-structure features can improve the service and the physical properties of such alloys. For intelligent microstructure design in the complex Al-based alloy, it is important to gain a deep physical understanding of the correlation between the microstructure and macroscopic properties, and thus atom probe tomography with its exceptional capabilities of spatially resolution and quantitative chemical analyses is presented as a sophisticated analytical tool to elucidate the underlying process of precipitation phenomena in aluminum alloys. A complete study examining the influence of common industrial heat treatment on the precipitation kinetics and phase transformations of complex aluminum alloy is performed. The qualitative evaluation results of the precipitation kinetics and phase transformation as functions of the heat treatment conditions are translated to engineer a complex aluminum alloy. The study demonstrates the ability to construct a robust microstructure with an excellent hardness behavior by applying a low-energy-consumption, cost-effective method. The proposed strategy to engineer complex aluminum alloys is based on both mechanical strategy and intelligent microstructural design. An intelligent microstructural design requires an investigation of the different strengthen phases, such as T1 (Al2CuLi), θ′(Al2Cu), β′(Al3Zr) and δ′(Al3Li). Therefore, the early stage of phase decomposition is examined in different binary Al-Li and Al-Cu alloys together with different

  2. Grindability of dental magnetic alloys.

    Science.gov (United States)

    Hayashi, Eisei; Kikuchi, Masafumi; Okuno, Osamu; Kimura, Kohei

    2005-06-01

    In this study, the grindability of cast magnetic alloys (Fe-Pt-Nb magnetic alloy and magnetic stainless steel) was evaluated and compared with that of conventional dental casting alloys (Ag-Pd-Au alloy, Type 4 gold alloy, and cobalt-chromium alloy). Grindability was evaluated in terms of grinding rate (i.e., volume of metal removed per minute) and grinding ratio (i.e., volume ratio of metal removed compared to wheel material lost). Solution treated Fe-Pt-Nb magnetic alloy had a significantly higher grinding rate than the aged one at a grinding speed of 750-1500 m x min(-1). At 500 m x min(-1), there were no significant differences in grinding rate between solution treated and aged Fe-Pt-Nb magnetic alloys. At a lower speed of 500 m x min(-1) or 750 m x min(-1), it was found that the grinding rates of aged Fe-Pt-Nb magnetic alloy and stainless steel were higher than those of conventional casting alloys.

  3. Interphase thermodynamic bond in heterogeneous alloys: effects on alloy properties

    International Nuclear Information System (INIS)

    Savchenko, A.M.; Konovalov, Yu.V.; Yuferov, O.I.

    2005-01-01

    Inconsistency between a conventional thermodynamic description of alloys as a mechanical mixture of phases and a real alloys state as a common thermodynamic system in which there is a complicated physical-chemical phases interaction has been considered. It is supposed that in heterogeneous alloys (eutectic ones, for instance), so called interphase thermodynamic bond can become apparent due to a partial electron levels splitting under phase interaction. Thermodynamic description of phase equilibrium in alloys is proposed taking into account a thermodynamic bond for the system with phase diagram of eutectic type, and methods of the value of this bond estimation are presented. Experimental evidence (Al-Cu-Si, Al-Si-Mg-Cu, U-Mo + Al) of the effect of interphase thermodynamic bond on temperature and enthalpy of melting of alloys are produced as well as possibility of its effects on alloys electrical conduction, strength, heat and corrosion resistance is substantiated theoretically [ru

  4. Properties- and applications of quasicrystals and complex metallic alloys.

    Science.gov (United States)

    Dubois, Jean-Marie

    2012-10-21

    This article aims at an account of what is known about the potential for applications of quasicrystals and related compounds, the so-called family of Complex Metallic Alloys (CMAs‡). Attention is focused at aluminium-based CMAs, which comprise a large number of crystalline compounds and quasicrystals made of aluminium alloyed with transition metals (like Fe or Cu) or normal metals like Mg. Depending on composition, the structural complexity varies from a few atoms per unit cell up to thousands of atoms. Quasicrystals appear then as CMAs of ultimate complexity and exhibit a lattice that shows no periodicity anymore in the usual 3-dimensional space. Properties change dramatically with lattice complexity and turn the metal-type behaviour of simple Al-based crystals into a far more complex behaviour, with a fingerprint of semi-conductors that may be exploited in various applications, potential or realised. An account of the ones known to the author is given in the light of the relevant properties, namely light absorption, reduced adhesion and friction, heat insulation, reinforcement of composites for mechanical devices, and few more exotic ones. The role played by the search for applications of quasicrystals in the development of the field is briefly addressed in the concluding section.

  5. Filler metal alloy for welding cast nickel aluminide alloys

    Science.gov (United States)

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

    1998-03-10

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

  6. Phase transformations and resulting microstructures in Ti - 47 Al -2 Cr alloy

    International Nuclear Information System (INIS)

    Ghasemi-Armaki, H.; Heshmati-Manesh, S.; Jafarian, H. R.; Nili-Ahmadabadi, M.

    2008-01-01

    During the last three decades, intermetallic alloys have focused attention because of their high strength to weight ratio and good creep resistance. Titanium aluminide alloys based on γ-Ti Al are potential candidates to replace Ni-based super alloys currently used in jet engine components at high temperatures because of their low density, high melting temperature, good elevated-temperature strength and modulus retention, high resistance to oxidation and hydrogen absorption, and excellent creep properties. One of the major concerns in these alloys is their poor ductility at room and intermediate temperatures which has been improved slightly by microstructure modifications through heat treatment. Thus, modification of microstructure during cooling and CCT diagram in these alloys is of vital importance. In this study, Ti - 47 Al - 2 Cr intermetallic alloy has been prepared by remelting 4 times with a vacuum arc remelting furnace. Homogenizing treatment was done at 1125 d eg C for 72 h in a sealed vacuum quartz tube. All heat treatments on the samples were carried out in a vacuum heat treatment furnace under a pressure of 10 -1 bar. The atmosphere inside the furnace was changed to that of high purity argon for each heat treatment as an added precaution against oxidation. In this paper, phase transformations in a γ-Ti Al based intermetallic alloy containing chromium were investigated. Heat treatments on samples of this alloy at temperatures above Tα and subsequent cooling with various cooling rates resulted in variety of microstructures. The schematic CCT diagram for this alloy was drawn from microstructural studies using microscopy routs and X-ray diffraction. Then, cyclic heat treatment with grain refining purpose was conducted on a sample of this alloy having massive gamma microstructure. During cyclic heat treatment, gradual dissociation of the gamma phase resulted in the formation of a Widmanstaetten type structure. Trend of microstructure evolution and

  7. Two phase titanium aluminide alloy

    Science.gov (United States)

    Deevi, Seetharama C.; Liu, C. T.

    2001-01-01

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

  8. SINTERED REFRACTORY TUNGSTEN ALLOYS. Gesinterte hochschmelzende wolframlegierungen

    Energy Technology Data Exchange (ETDEWEB)

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

    1971-12-15

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

  9. Group precipitation and age hardening of nanostructured Fe-based alloys with ultra-high strengths

    Science.gov (United States)

    Jiao, Z. B.; Luan, J. H.; Miller, M. K.; Yu, C. Y.; Liu, C. T.

    2016-01-01

    The precipitation of nanoparticles plays a key role in determining the properties of many structural materials, and the understanding of their formation and stabilization mechanisms has been a long standing interest in the material field. However, the critical issues involving the group precipitation of various nanoparticles and their cooperative hardening mechanism remain elusive in the newly discovered Fe-based alloys with nanostructures. Here we quantitatively elucidate the nucleation mechanism, evolution kinetics and hardening effects of the group-precipitated nanoparticles in the Fe-Cu-Ni-Al-based alloys by atom probe tomography together with both first-principles and thermodynamic calculations. Our results provide the compelling evidence for two interesting but complex group precipitation pathways of nanoparticles, i.e., the Cu-rich and NiAl-based precipitations. The co-existence of the two precipitation pathways plays a key role in age hardening kinetics and ultimately enhances the hardening response, as compared to the single particle type of strengthening, therefore providing an effective new approach for strengthening materials for structural applications. PMID:26892834

  10. Metastable superconducting alloys

    International Nuclear Information System (INIS)

    Johnson, W.L.

    1978-07-01

    The study of metastable metals and alloys has become one of the principal activities of specialists working in the field of superconducting materials. Metastable crystalline superconductors such as the A15-type materials have been given much attention. Non-crystalline superconductors were first studied over twenty years ago by Buckel and Hilsch using the technique of thin film evaporation on a cryogenic substrate. More recently, melt-quenching, sputtering, and ion implantation techniques have been employed to produce a variety of amorphous superconductors. The present article presents a brief review of experimental results and a survey of current work on these materials. The systematics of superconductivity in non-crystalline metals and alloys are described along with an analysis of the microscopic parameters which underlie the observed trends. The unique properties of these superconductors which arise from the high degree of structural disorder in the amorphous state are emphasized

  11. Rare earth metal alloy magnets

    International Nuclear Information System (INIS)

    Harris, I.R.; Evans, J.M.; Nyholm, P.S.

    1979-01-01

    This invention relates to rare earth metal alloy magnets and to methods for their production. The technique is based on the fact that rare earth metal alloys (for e.g. cerium or yttrium) which have been crumbled to form a powder by hydride formation and decomposition can be used for the fabrication of magnets without the disadvantages inherent in alloy particle size reduction by mechanical milling. (UK)

  12. Thermomechanical treatment of titanium alloys

    International Nuclear Information System (INIS)

    Khorev, A.K.

    1979-01-01

    The problems of the theory and practical application of thermomechanical treatment of titanium alloys are presented. On the basis of the systematic investigations developed are the methods of thermomechanical treatment of titanium alloys, established are the optimum procedures and produced are the bases of their industrial application with an account of alloy technological peculiarities and the procedure efficiency. It is found that those strengthening methods are more efficient at which the contribution of dispersion hardening prevails over the strengthening by phase hardening

  13. Alloy catalyst material

    DEFF Research Database (Denmark)

    2014-01-01

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

  14. Superplasticity of amorphous alloy

    International Nuclear Information System (INIS)

    Levin, Yu.B.; Likhachev, V.L.; Sen'kov, O.N.

    1988-01-01

    Results of mechanical tests of Co 57 Ni 10 Fe 5 Si 11 B 17 amorphous alloy are presented and the effect of crystallization, occurring during deformation process, on plastic low characteristics is investiagted. Superplasticity of amorphous tape is investigated. It is shown, that this effect occurs only when during deformation the crystallization takes place. Process model, based on the usage disclination concepts about glass nature, is suggested

  15. Shape memory alloy actuator

    Science.gov (United States)

    Varma, Venugopal K.

    2001-01-01

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

  16. Nickel base alloys

    International Nuclear Information System (INIS)

    Gibson, R.C.; Korenko, M.K.

    1980-01-01

    The specified alloys consist of Ni, Cr and Fe as main constituents, and Mo, Nb, Si, Zr, Ti, Al, C and B as minor constituents. They are said to exhibit high weldability and long-time structural stability, as well as low swelling under nuclear radiation conditions, making them especially suitable for use as a duct material and control element cladding for sodium-cooled nuclear reactors. (U.K.)

  17. Influence of Y, Gd and Sm on the glass forming ability and thermal crystallization of aluminum based alloy; Efeito das terras raras Y, Gd e Sm na tendencia a formacao de amorfo e na cristalizacao termica em ligas a base de aluminio

    Energy Technology Data Exchange (ETDEWEB)

    Aliaga, L.C.R.; Bolfarini, C.; Kiminami, C.S.; Botta Filho, W.J., E-mail: aliaga@ufscar.b [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais; Danez, G.P. [Universidade Federal de Sao Carlos (PPG-CEMUFSCar), SP (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais

    2010-07-01

    Al-based amorphous alloys represent an important family of metals and a great scientific activity has been devoted to determine the main features of both glass forming ability (GFA) and crystallization behavior in order to have a comprehensive framework aimed at potential technological applications. Nowadays, it is well known that the best Al-based amorphous alloys are formed in ternary systems such as Al- RE-TM, where RE is a rare earth and TM a transition metal. This paper presents results of research in Al{sub 85}Ni{sub 10}RE{sub 5} alloys (RE = Y, Gd and Sm). Amorphous ribbons were processed by melt-spinning under the same conditions and subsequently characterized by x-ray diffraction (XRD) and differential scanning calorimetry (DSC). Results show appreciable micro structural differences as function of the rare earth, thus crystal is obtained for Y, nano-glassy for Gd and, fully amorphous structure for Sm. (author)

  18. Aluminum alloy impact sparkling

    Directory of Open Access Journals (Sweden)

    M. Dudyk

    2008-08-01

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

  19. Lithium alloy negative electrodes

    Science.gov (United States)

    Huggins, Robert A.

    The 1996 announcement by Fuji Photo Film of the development of lithium batteries containing convertible metal oxides has caused a great deal of renewed interest in lithium alloys as alternative materials for use in the negative electrode of rechargeable lithium cells. The earlier work on lithium alloys, both at elevated and ambient temperatures is briefly reviewed. Basic principles relating thermodynamics, phase diagrams and electrochemical properties under near-equilibrium conditions are discussed, with the Li-Sn system as an example. Second-phase nucleation, and its hindrance under dynamic conditions plays an important role in determining deviations from equilibrium behavior. Two general types of composite microstructure electrodes, those with a mixed-conducting matrix, and those with a solid electrolyte matrix, are discussed. The Li-Sn-Si system at elevated temperatures, and the Li-Sn-Cd at ambient temperatures are shown to be examples of mixed-conducting matrix microstructures. The convertible oxides are an example of the solid electrolyte matrix type. Although the reversible capacity can be very large in this case, the first cycle irreversible capacity required to convert the oxides to alloys may be a significant handicap.

  20. Low activation vanadium alloys

    International Nuclear Information System (INIS)

    Witzenburg, W. van.

    1991-01-01

    The properties and general characteristics of vanadium-base alloys are reviewed in terms of the materials requirements for fusion reactor first wall and blanket structures. In this review attention is focussed on radiation response including induced radioactivity, mechanical properties, compatibility with potential coolants, physical and thermal properties, fabricability and resources. Where possible, properties are compared to those of other leading candidate structural materials, e.g. austenitic and ferritic/martensitic steels. Vanadium alloys appear to offer advantages in the areas of long-term activation, mechanical properties at temperatures above 600 deg C, radiation resistance and thermo-hydraulic design, due to superior physical and thermal properties. They also have a potential for higher temperature operation in liquid lithium systems. Disadvantages are associated with their ability to retain high concentrations of hydrogen isotopes, higher cost, more difficult fabrication and welding. A particular concern regarding use of vanadium alloys relates their reactivity with non-metallic elements, such as oxygen and nitrogen. (author). 33 refs.; 2 figs.; 2 tabs

  1. Correlation between the electrical properties and the interfacial microstructures of TiAl-based ohmic contacts to p-type 4H-SiC

    Science.gov (United States)

    Tsukimoto, S.; Nitta, K.; Sakai, T.; Moriyama, M.; Murakami, Masanori

    2004-05-01

    In order to understand a mechanism of TiAl-based ohmic contact formation for p-type 4H-SiC, the electrical properties and microstructures of Ti/Al and Ni/Ti/Al contacts, which provided the specific contact resistances of approximately 2×10-5 Ω-cm2 and 7×10-5 Ω-cm2 after annealing at 1000°C and 800°C, respectively, were investigated using x-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). Ternary Ti3SiC2 carbide layers were observed to grow on the SiC surfaces in both the Ti/Al and the Ni/Ti/Al contacts when the contacts yielded low resistance. The Ti3SiC2 carbide layers with hexagonal structures had an epitaxial orientation relationship with the 4H-SiC substrates. The (0001)-oriented terraces were observed periodically at the interfaces between the carbide layers and the SiC, and the terraces were atomically flat. We believed the Ti3SiC2 carbide layers primarily reduced the high Schottky barrier height at the contact metal/p-SiC interface down to about 0.3 eV, and, thus, low contact resistances were obtained for p-type TiAl-based ohmic contacts.

  2. Corrosion resistance of Al-based coatings in flowing Pb–15.7Li produced by aluminum electrodeposition from ionic liquids

    Directory of Open Access Journals (Sweden)

    Sven-Erik Wulf

    2016-12-01

    Full Text Available Reduced activation ferritic–martensitic steels are intended to serve as structural materials in different blanket designs, e.g. HCLL, DCLL and WCLL. In these designs the material is supposed to be in direct contact with the flowing liquid breeder material Pb–15.7Li at an operating temperature of up to 550°C. These conditions will lead to severe corrosion attack of the steel and high corrosion rates of up to 400µm per year are reported in the literature. To avoid or reduce corrosion Al-based corrosion barriers were developed in the last years by using electrochemical techniques to deposit aluminum. Until now two processes have been developed. The first one, so called ECA process, is based on volatile toluene electrolytes. Long-term corrosion experiments on these coatings indicated reduced corrosion rates compared to bare Eurofer steel in flowing Pb–15.7Li. However, these Fe–Al scales showed inhomogeneous corrosion attack of the corrosion barrier itself. In this study the improved ECX process was applied to produce Al-based coatings. The short-term corrosion behavior of such barrier coatings was analyzed for up to 4000h by diameter measurements and metallographic examinations. The investigation revealed uniform corrosion in comparison to inhomogeneous attack in case of ECA coated samples and reduced corrosion rates of around 20µm/a even for low exposure times of 4000h.

  3. Impact toughness of laser alloyed aluminium AA1200 alloys

    CSIR Research Space (South Africa)

    Mabhali, Luyolo AB

    2013-08-01

    Full Text Available ),. 559-563. [2] T. Tomida, K. Nakata, S. Saji, T. Kubo, T, Formation of metal matrix composite layer on aluminium alloy with TiC-Cu powder by laser surface alloying process; Surface and Coatings Technology; vol. 142-144, 2001, 585-589. [3] L. A. B...

  4. Titanium alloys. Advances in alloys, processes, products and applications

    International Nuclear Information System (INIS)

    Blenkinsop, P.A.

    1993-01-01

    The last few years have been a period of consolidation of existing alloys and processes. While the aerospace industry remains the principal driving force for alloy development, the paper illustrates examples of new markets being established in 'older' alloys, by a combination of product/process development and a re-examination of engineering design parameters. Considerable attention is still being directed towards the titanium aluminide systems, but other more conventional alloy developments are underway aimed at specific engineering and process requirements, both in the aerospace and non-aerospace sectors. Both the advanced high temperature and conventional alloy developments are considered, before the paper goes on to assess the potential of new processes and products, like spray-forming, metal matrix composites and shaped-plate rolling. (orig.)

  5. Alloy development for cladding and duct applications

    International Nuclear Information System (INIS)

    Straalsund, J.L.; Johnson, G.D.

    1981-01-01

    Three general classes of materials under development for cladding and ducts are listed. Solid solution strengthened, or austenitic, alloys are Type 316 stainless steel and D9. Precipitation hardened (also austenitic) alloys consist of D21, D66 and D68. These alloys are similar to such commercial alloys as M-813, Inconel 706, Inconel 718 and Nimonic PE-16. The third general class of alloys is composed of ferritic alloys, with current emphasis being placed on HT-9, a tempered martensitic alloy, and D67, a delta-ferritic steel. The program is comprised of three parallel paths. The current reference, or first generation alloy, is 20% cold worked Type 316 stainless steel. Second generation alloys for near-term applications include D9 and HT-9. Third generation materials consist of the precipitation strengthened steels and ferritic alloys, and are being considered for implementation at a later time than the first and second generation alloys. The development of second and third generation materials was initiated in 1974 with the selection of 35 alloys. This program has proceeded to today where there are six advanced alloys being evaluated. These alloys are the developmental alloys D9, D21, D57, D66 and D68, together with the commerical alloy, HT-9. The status of development of these alloys is summarized

  6. ODS Alloys for Nuclear Applications

    International Nuclear Information System (INIS)

    Jang, Jin Sung

    2006-01-01

    ODS (oxide dispersion strengthening) alloy is one of the potential candidate alloys for the cladding or in reactor components of Generation IV reactors and for the structural material even for fusion reactors. It is widely accepted as very resistant material to neutron irradiation as well as strong material at high temperature due to its finely distributed and stable oxide particles. Among Generation IV reactors SFR and SCWR are anticipated in general to run in the temperature range between 300 and 550 .deg. C, and the peak cladding temperature is supposed to reach at about 620 .deg. C during the normal operation. Therefore Zr.base alloys, which have been widely known and adopted for the cladding material due to their excellent neutron economics, are no more adequate at these operating conditions. Fe-base ODS alloys in general has a good high temperature strength at the above high temperature as well as the neutron resistance. In this study a range of commercial grade ODS alloys and their applications are reviewed, including an investigation of the stability of a commercial grade 20% Cr Fe-base ODS alloy(MA956). The alloy was evaluated in terms of the fracture toughness change along with the aging treatment. Also an attempt of the development of 9% Cr Fe-base ODS alloys is introduced

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

    International Nuclear Information System (INIS)

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

    2002-01-01

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

  8. Nickel alloys and high-alloyed special stainless steels. Properties, manufacturing, applications. 4. compl. rev. ed.

    International Nuclear Information System (INIS)

    Heubner, Ulrich; Kloewer, Jutta; Alves, Helena; Behrens, Rainer; Schindler, Claudius; Wahl, Volker; Wolf, Martin

    2012-01-01

    This book contains the following eight topics: 1. Nickel alloys and high-alloy special stainless steels - Material overview and metallurgical principles (U. Heubner); 2. Corrosion resistance of nickel alloys and high-alloy special stainless steels (U. Heubner); 3. Welding of nickel alloys and high-alloy special stainless steels (T. Hoffmann, M. Wolf); 4. High-temperature materials for industrial plant construction (J. Kloewer); 5. Nickel alloys and high-alloy special stainless steels as hot roll clad composites-a cost-effective alternative (C. Schindler); 6. Selected examples of the use of nickel alloys and high-alloy special stainless steels in chemical plants (H. Alves); 7. The use of nickel alloys and stainless steels in environmental engineering (V. Wahl); 8: Nickel alloys and high-alloy special stainless steels for the oil and gas industry (R. Behrens).

  9. Corrosion of aluminum alloys as a function of alloy composition

    International Nuclear Information System (INIS)

    Johnson, A.B. Jr.

    1969-10-01

    A study was initiated which included nineteen aluminum alloys. Tests were conducted in high purity water at 360 0 C and flow tests (approx. 20 ft/sec) in reactor process water at 130 0 C (TF-18 loop tests). High-silicon alloys and AlSi failed completely in the 360 0 C tests. However, coupling of AlSi to 8001 aluminum suppressed the failure. The alloy compositions containing iron and nickel survived tht 360 0 C autoclave exposures. Corrosion rates varied widely as a function of alloy composition, but in directions which were predictable from previous high-temperature autoclave experience. In the TF-18 loop flow tests, corrosion penetrations were similar on all of the alloys and on high-purity aluminum after 105 days. However, certain alloys established relatively low linear corrosion rates: Al-0.9 Ni-0.5 Fe-0.1 Zr, Al-1.0 Ni-0.15 Fe-11.5 Si-0.8 Mg, Al-1.2 Ni-1.8 Fe, and Al-7.0 Ni-4.8 Fe. Electrical polarity measurements between AlSi and 8001 alloys in reactor process water at temperatures up to 150 0 C indicated that AlSi was anodic to 8001 in the static autoclave system above approx. 50 0 C

  10. Aluminum alloy and associated anode and battery

    International Nuclear Information System (INIS)

    Tarcy, G.P.

    1990-01-01

    This patent describes an aluminum alloy. It comprises: eutectic amounts of at least two alloying elements selected from the group consisting of bismuth, cadmium, scandium, gallium, indium, lead, mercury, thallium, tin, and zinc with the balance being aluminum and the alloying elements being about 0.01 to 3.0 percent by weight of the alloy

  11. Stress Corrosion Cracking of Certain Aluminum Alloys

    Science.gov (United States)

    Hasse, K. R.; Dorward, R. C.

    1983-01-01

    SC resistance of new high-strength alloys tested. Research report describes progress in continuing investigation of stress corrosion (SC) cracking of some aluminum alloys. Objective of program is comparing SC behavior of newer high-strength alloys with established SC-resistant alloy.

  12. General characteristics of eutectic alloy solidification mechanisms

    International Nuclear Information System (INIS)

    Lemaignan, Clement.

    1977-01-01

    The eutectic alloy sodification was studied in binary systems: solidification of non facetted - non facetted eutectic alloy (theoretical aspects, variation of the lamellar spacing, crystallographic relation between the various phases); solidification of facetted - non facetted eutectic alloy; coupled growth out of eutectic alloy; eutectic nucleation [fr

  13. Pareto-optimal alloys

    DEFF Research Database (Denmark)

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

    2003-01-01

    Large databases that can be used in the search for new materials with specific properties remain an elusive goal in materials science. The problem is complicated by the fact that the optimal material for a given application is usually a compromise between a number of materials properties and the ......Large databases that can be used in the search for new materials with specific properties remain an elusive goal in materials science. The problem is complicated by the fact that the optimal material for a given application is usually a compromise between a number of materials properties...... 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......, the Pareto-optimal set, to determine optimal alloy solutions for the compromise between low compressibility, high stability, and cost....

  14. Enhancing elevated temperature strength of copper containing aluminium alloys by forming L12 Al3Zr precipitates and nucleating θ″ precipitates on them.

    Science.gov (United States)

    Kumar Makineni, Surendra; Sugathan, Sandeep; Meher, Subhashish; Banerjee, Rajarshi; Bhattacharya, Saswata; Kumar, Subodh; Chattopadhyay, Kamanio

    2017-09-11

    Strengthening by precipitation of second phase is the guiding principle for the development of a host of high strength structural alloys, in particular, aluminium alloys for transportation sector. Higher efficiency and lower emission demands use of alloys at higher operating temperatures (200 °C-250 °C) and stresses, especially in applications for engine parts. Unfortunately, most of the precipitation hardened aluminium alloys that are currently available can withstand maximum temperatures ranging from 150-200 °C. This limit is set by the onset of the rapid coarsening of the precipitates and consequent loss of mechanical properties. In this communication, we present a new approach in designing an Al-based alloy through solid state precipitation route that provides a synergistic coupling of two different types of precipitates that has enabled us to develop coarsening resistant high-temperature alloys that are stable in the temperature range of 250-300 °C with strength in excess of 260 MPa at 250 °C.

  15. Ab initio study on the thermal properties of the fcc Al3Mg and Al3Sc alloys

    International Nuclear Information System (INIS)

    Li Donglin; Chen Ping; Yi Jianxiong; Tang Biyu; Peng Liming; Ding Wenjiang

    2009-01-01

    Ab initio density functional theory (DFT) and density function perturbation theory (DFPT) have been used to investigate the thermal properties of the fcc Al 3 Mg and Al 3 Sc alloys over a wide range of pressure and temperature, in comparison with fcc Al. Phonon dispersions were obtained at equilibrium and strained configurations by density functional perturbation theory. Using the quasiharmonic approximation for the free energy, several thermal quantities of interest, such as the thermal Grueneisen parameter, heat capacity, thermal expansion coefficient and entropy, were calculated as a function of temperature and pressure, and the variation features of these quantities were discussed in detail. This investigation provides useful information for design and applications of technologically relevant Al-based alloys.

  16. L2 droplet interaction with α-Al during solidification of hypermonotectic Al-8 wt.% Bi alloys

    International Nuclear Information System (INIS)

    Schaffer, P.L.; Mathiesen, R.H.; Arnberg, L.

    2009-01-01

    Studies of Al-based hypermonotectics have so far focused mainly on droplet motion and coagulation dynamics, with limited attention given to the interaction between droplets and the advancing solidification front which is decisive for the final distribution of the second phase within the α-Al matrix. The current work presents results from directional solidification experiments with Al-8 wt.% Bi alloys. It was found that droplets with large radii were frequently pushed and small droplets were engulfed. This is contradictory to the many models that have been proposed to explain pushing/engulfment of solid particles and can in part be ascribed to the fact that while solid-particle models only consider single, non-interacting particles that remain unaffected by solutal gradients ahead of the advancing solidification front, droplet-droplet interaction and local solute gradients have been found to be critical for droplet pushing/engulfment behaviour in hypermonotectic alloys.

  17. Density of Liquid Ni-Cr Alloy

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

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

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

    National Research Council Canada - National Science Library

    Chen, Kuiying; Cheng, Leon M

    2006-01-01

    ... and Co in cubic solid solution of Fe-Ga alloys. Mayer bond order "BO" values were used to evaluate the atomic bond strengths in the alloys, and were then used to assess the alloying strengthening characteristics...

  19. Development of powder metallurgy 2XXX series Al alloys for high temperature aircraft structural applications

    Science.gov (United States)

    Chellman, D. J.

    1984-01-01

    The objective of the present investigation was to improve the strength and fracture toughness combination of P/M 2124 Al alloys in accordance with NASA program goals for damage tolerance and fatigue resistance. Two (2) P/M compositions based on Al-3.70 Cu-1.85 Mg-0.20 Mn with 0.12 and 0.60 wt. pct. Zr were selected for investigation. The rapid solidification rates produced by atomization were observed to prohibit the precipitation of coarse, primary Al3Zr in both alloys. A major portion of the Zr precipitated as finely distributed, coherent Al3Zr phases during vacuum preheating and solution heat treatment. The proper balance between Cu and Mg contents eliminated undissolved, soluble constituents such as Al2CuMg and Al2Cu during atomization. The resultant extruded microstructures produced a unique combination of strength and fracture toughness. An increase in the volume fraction of coherent Al3Zr, unlike incoherent Al20Cu2Mn3 dispersoids, strengthened the P/M Al base alloy either directly by dislocation-precipitate interactions, indirectly by a retardation of recrystallization, or a combination of both mechanisms. Furthermore, coherent Al3Zr does not appear to degrade toughness to the extent that incoherent Al20Cu2Mn3 does. Consequently, the addition of 0.60 wt. pct. Zr to the base alloy, incorporated with a 774K (935 F) solution heat treatment temperature, produces an alloy which exceeds all tensile property and fracture toughness goals for damage tolerant and fatigue resistant applications in the naturally aged condition.

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

    African Journals Online (AJOL)

    eobe

    1,2 DEPARTMENT OF METALLURGICAL AND MATERIALS ENGINEERING, UNIVERSITY OF NIGERIA, NSUKKA, NIGERIA. 2 DEPT ... a result of this structural change, titanium alloys fall ... the phase stability and mechanical behaviours of Ti-.

  1. Laser surface alloying of aluminium-transition metal alloys

    Directory of Open Access Journals (Sweden)

    Almeida, A.

    1998-04-01

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

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

  2. Radiation Resistance of the U(Al, Si)3 Alloy: Ion-Induced Disordering

    Science.gov (United States)

    Yaniv, Gili; Horak, Pavel; Vacik, Jiri; Mykytenko, Natalia; Rafailov, Gennady; Dahan, Itzchak; Fuks, David; Kiv, Arik

    2018-01-01

    During the exploitation of nuclear reactors, various U-Al based ternary intermetallides are formed in the fuel-cladding interaction layer. Structure and physical properties of these intermetallides determine the radiation resistance of cladding and, ultimately, the reliability and lifetime of the nuclear reactor. In current research, U(Al, Si)3 composition was studied as a potential constituent of an interaction layer. Phase content of the alloy of an interest was ordered U(Al, Si)3, structure of which was reported earlier, and pure Al (constituting less than 20 vol % of the alloy). This alloy was investigated prior and after the irradiation performed by Ar ions at 30 keV. The irradiation was performed on the transmission electron microscopy (TEM, JEOL, Japan) samples, characterized before and after the irradiation process. Irradiation induced disorder accompanied by stress relief. Furthermore, it was found that there is a dose threshold for disordering of the crystalline matter in the irradiated region. Irradiation at doses equal or higher than this threshold resulted in almost solely disordered phase. Using the program “Stopping and Range of Ions in Matter” (SRIM), the parameters of penetration of Ar ions into the irradiated samples were estimated. Based on these estimations, the dose threshold for ion-induced disordering of the studied material was assessed. PMID:29393870

  3. Method of mechanochemical synthesis for the production of nanocrystalline Nb-Al alloys

    International Nuclear Information System (INIS)

    Portnoj, V.K.; Tret'yakov, K.V.; Logacheva, A.I.; Logunov, A.V.; Razumovskij, I.M.

    2004-01-01

    Using X-ray diffraction and DS analyses the process of solid phase synthesis on cooperative comminution of components (Nb, Al, Cr) in a planetary ball mill is investigated. Powder nanocrystalline Nb 3 Al base alloys of various compositions with simultaneous introduction of chromium are synthesized. High power milling results in block size of ∼ 20 nm. It is shown that final chromium dissolution and partial decomposition of Nb(Al) supersaturated solid solutions proceed after heating up to 1100 deg C only. With the help of doping with niobium by the method of mechanical alloying, a two-phase alloy Nb 3 Al + Nb 2 Al having been produced by arc melting, is corrected by composition and transferred to the two-phase region of Nb 3 Al + Nb(Al). It is revealed that the process of niobium aluminide phase formation during mechanochemical synthesis and the process of mechanical activation of Nb-Al system intermetallics enriched with niobium always proceed through formation of supersaturated solid solutions. The mechanism of the process is probably associated with stacking faults formation due to deformation [ru

  4. Manufacturing of High Entropy Alloys

    Science.gov (United States)

    Jablonski, Paul D.; Licavoli, Joseph J.; Gao, Michael C.; Hawk, Jeffrey A.

    2015-07-01

    High entropy alloys (HEAs) have generated interest in recent years due to their unique positioning within the alloy world. By incorporating a number of elements in high proportion they have high configurational entropy, and thus they hold the promise of interesting and useful properties such as enhanced strength and phase stability. The present study investigates the microstructure of two single-phase face-centered cubic (FCC) HEAs, CoCrFeNi and CoCrFeNiMn, with special attention given to melting, homogenization and thermo-mechanical processing. Large-scale ingots were made by vacuum induction melting to avoid the extrinsic factors inherent in small-scale laboratory button samples. A computationally based homogenization heat treatment was applied to both alloys in order to eliminate segregation due to normal ingot solidification. The alloys fabricated well, with typical thermo-mechanical processing parameters being employed.

  5. Nickel and cobalt base alloys

    International Nuclear Information System (INIS)

    Houlle, P.

    1994-01-01

    Nickel base alloys have a good resistance to pitting, cavernous or cracks corrosion. Nevertheless, all the nickel base alloys are not equivalent. Some differences exit between all the families (Ni, Ni-Cu, Ni-Cr-Fe, Ni-Cr-Fe-Mo/W-Cu, Ni-Cr-Mo/W, Ni-Mo). Cobalt base alloys in corrosive conditions are generally used for its wear and cracks resistance, with a compromise to its localised corrosion resistance properties. The choice must be done from the perfect knowledge of the corrosive medium and of the alloys characteristics (chemical, metallurgical). A synthesis of the corrosion resistance in three medium (6% FeCl 3 , 4% NaCl + 1% HCl + 0.1% Fe 2 (SO 4 ) 3 , 11.5% H 2 SO 4 + 1.2% HCl + 1% Fe 2 (SO 4 ) 3 + 1% CuCl 2 ) is presented. (A.B.). 11 refs., 1 fig., 12 tabs

  6. Magnetoimpedance effect in Nanoperm alloys

    International Nuclear Information System (INIS)

    Hernando, B.; Alvarez, P.; Santos, J.D.; Gorria, P.; Sanchez, M.L.; Olivera, J.; Perez, M.J.; Prida, V.M.

    2006-01-01

    The influence of isothermal annealing (1 h at 600 deg. C in Ar atmosphere) on the soft magnetic properties and magnetoimpedance (MI) effect has been studied in ribbons of the following Nanoperm alloys: Fe 91 Zr 7 B 2 , Fe 88 Zr 8 B 4 , Fe 87 Zr 6 B 6 Cu 1 and Fe 8 Zr 1 B 1 . A maximum MI ratio of about 27% was measured for the nanocrystalline alloy Fe 87 Zr 6 B 6 Cu 1 at a driving frequency of 0.2 MHz. The thermal annealing led to magnetic softening for this alloy, while a hardening is observed for the Fe 8 Zr 1 B 1 alloy

  7. Emissivity measurements on aeronautical alloys

    International Nuclear Information System (INIS)

    Campo, L. del; Perez-Saez, R.B.; Gonzalez-Fernandez, L.; Esquisabel, X.; Fernandez, I.; Gonzalez-Martin, P.; Tello, M.J.

    2010-01-01

    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 μm), sample temperature (200-650 o C) and emission angle (0-85 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.

  8. Emissivity measurements on aeronautical alloys

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-01-21

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

  9. First principles thermodynamics of alloys

    International Nuclear Information System (INIS)

    Ducastelle, F.

    1993-01-01

    We present a brief report on the methods of solid state physics (electronic structure, statistical thermodynamics) that allow us to discuss the phase stability of alloys and to determine their phase diagrams. (orig.)

  10. Auger electron spectroscopy of alloys

    International Nuclear Information System (INIS)

    Kuijers, F.J.

    1978-01-01

    This thesis describes how the surface compositions of some alloys can be determined by Auger Electron Spectroscopy (AES). The motivation for this research and the reasons for the choice of alloy systems studied are formulated. The theoretical background of AES is briefly discussed and the apparatus used and the experimental procedures applied are described. Four alloy systems have been investigated in this thesis - Ni-Cu and Pd - Ag (consisting of a component active in most cataytic reactions - Ni and Pd; and a component which is almost inactive for a number of reactions - Cu and Ag) and Pt - Pd and Pt-Ir (consisting of two active components). Knowledge of the surface composition of the various alloy systems is shown to be essential for the interpretation of catalytic results. (Auth./C.F.)

  11. Derivative spectrophotometry of cobalt alloys

    International Nuclear Information System (INIS)

    Spitsyn, P.K.

    1985-01-01

    The method of derivative spectrophotometry is briefly described, and derivative absorption spectra are presented for samarium, cobalt, and commercial Sm-Co alloys. It is shown that the use of derivative spectrophotometry not only improves the accuracy and selectivity of element determinations but also simplifies the analysis of alloys. Results of a statistical evaluation of the metrological characteristics of the analytical procedure described here are presented. 8 references

  12. Volatilization from PCA steel alloy

    Energy Technology Data Exchange (ETDEWEB)

    Hagrman, D.L.; Smolik, G.R.; McCarthy, K.A.; Petti, D.A.

    1996-08-01

    The mobilizations of key components from Primary Candidate Alloy (PCA) steel alloy have been measured with laboratory-scale experiments. The experiments indicate most of the mobilization from PCA steel is due to oxide formation and spalling but that the spalled particles are large enough to settle rapidly. Based on the experiments, models for the volatization of iron, manganese, and cobalt from PCA steel in steam and molybdenum from PCA steel in air have been derived.

  13. The microstructures of ordered alloys

    International Nuclear Information System (INIS)

    Sarma, G.M.K.; Ranganathan, S.

    1977-01-01

    The phenomenon of ordering in substitutional alloys confers special properties on them by introducing various types of structures and structural defects. Some of the important structural defects (translational and rotational antiphase boundaries, dissociated antiphase boundaries and superdislocations) and their observation by various microscopical methods, with particular emphasis on the applications of the electron microscope are described with illustrations drawn from the studies on nickel-molybdenum and nickel-tungsten alloys. (M.G.B.)

  14. Laser welding of aluminium alloys

    OpenAIRE

    Forsman, Tomas

    2000-01-01

    This thesis treats laser welding of aluminium alloys from a practical perspective with elements of mathematical analysis. The theoretical work has in all cases been verified experimentally. The aluminium alloys studied are from the 5xxx and 6xxx groups which are common for example in the automotive industry. Aluminium has many unique physical properties. The properties which more than others have been shown to influence the welding process is its high reflection, high thermal conductivity, lo...

  15. Electrical conductivity in random alloys

    International Nuclear Information System (INIS)

    Mookerjee, A.; Thakur, P.K.; Yussouff, M.

    1984-12-01

    Based on the augmented space formalism introduced by one of us and the use of the Ward identity and the Bethe-Sapeter equation, a formalism has been developed for the calculation of electrical conductivity for random alloys. A simple application is made to a model case, and it is argued that the formalism enables us to carry out viable calculations on more realistic models of alloys. (author)

  16. Electrical conductivity in random alloys

    International Nuclear Information System (INIS)

    Mookerjee, A.; Yussouff, M.

    1983-06-01

    Starting from the augmented space formalism by one of us, and the use of the Ward identity and Bethe Salpeter equation, a complete formalism for the calculation of the electrical conductivity in tight-binding models of random binary alloys has been developed. The formalism is practical in the sense that viable calculations may be carried out with its help for realistics models of alloy systems. (author)

  17. High-Temperature Oxidation-Resistant and Low Coefficient of Thermal Expansion NiAl-Base Bond Coat Developed for a Turbine Blade Application

    Science.gov (United States)

    2003-01-01

    Many critical gas turbine engine components are currently made from Ni-base superalloys that are coated with a thermal barrier coating (TBC). The TBC consists of a ZrO2-based top coat and a bond coat that is used to enhance the bonding between the superalloy substrate and the top coat. MCrAlY alloys (CoCrAlY and NiCrAlY) are currently used as bond coats and are chosen for their very good oxidation resistance. TBC life is frequently limited by the oxidation resistance of the bond coat, along with a thermal expansion mismatch between the metallic bond coat and the ceramic top coat. The aim of this investigation at the NASA Glenn Research Center was to develop a new longer life, higher temperature bond coat by improving both the oxidation resistance and the thermal expansion characteristics of the bond coat. Nickel aluminide (NiAl) has excellent high-temperature oxidation resistance and can sustain a protective Al2O3 scale to longer times and higher temperatures in comparison to MCrAlY alloys. Cryomilling of NiAl results in aluminum nitride (AlN) formation that reduces the coefficient of thermal expansion (CTE) of the alloy and enhances creep strength. Thus, additions of cryomilled NiAl-AlN to CoCrAlY were examined as a potential bond coat. In this work, the composite alloy was investigated as a stand-alone substrate to demonstrate its feasibility prior to actual use as a coating. About 85 percent of prealloyed NiAl and 15 percent of standard commercial CoCrAlY alloys were mixed and cryomilled in an attritor with stainless steel balls used as grinding media. The milling was carried out in the presence of liquid nitrogen. The milled powder was consolidated by hot extrusion or by hot isostatic pressing. From the consolidated material, oxidation coupons, four-point bend, CTE, and tensile specimens were machined. The CTE measurements were made between room temperature and 1000 C in an argon atmosphere. It is shown that the CTE of the NiAl-AlN-CoCrAlY composite bond coat

  18. Impact of neutron irradiation on mechanical performance of FeCrAl alloy laser-beam weldments

    Science.gov (United States)

    Gussev, M. N.; Cakmak, E.; Field, K. G.

    2018-06-01

    Oxidation-resistant iron-chromium-aluminum (FeCrAl) alloys demonstrate better performance in Loss-of-Coolant Accidents, compared with austenitic- and zirconium-based alloys. However, further deployment of FeCrAl-based materials requires detailed characterization of their performance under irradiation; moreover, since welding is one of the key operations in fabrication of light water reactor fuel cladding, FeCrAl alloy weldment performance and properties also should be determined prior to and after irradiation. Here, advanced C35M alloy (Fe-13%Cr-5%Al) and variants with aluminum (+2%) or titanium carbide (+1%) additions were characterized after neutron irradiation in Oak Ridge National Laboratory's High Flux Isotope Reactor at 1.8-1.9 dpa in a temperature range of 195-559 °C. Specimen sets included as-received (AR) materials and specimens after controlled laser-beam welding. Tensile tests with digital image correlation (DIC), scanning electron microscopy-electron back scatter diffraction analysis, fractography, and x-ray tomography analysis were performed. DIC allowed for investigating local yield stress in the weldments, deformation hardening behavior, and plastic anisotropy. Both AR and welded material revealed a high degree of radiation-induced hardening for low-temperature irradiation; however, irradiation at high-temperatures (i.e., 559 °C) had little overall effect on the mechanical performance.

  19. Mechanical behavior and related microstructural aspects of a nano-lamellar TiAl alloy at elevated temperatures

    International Nuclear Information System (INIS)

    Klein, T.; Usategui, L.; Rashkova, B.; Nó, M.L.; San Juan, J.; Clemens, H.; Mayer, S.

    2017-01-01

    Advanced intermetallic γ-TiAl based alloys, which solidify via the disordered β phase, such as the TNM"+ alloy, are considered as most promising candidates for structural applications at high temperatures in aero and automotive industries, where they are applied increasingly. Particularly creep resistant microstructures required for high-temperature application, i.e. fine fully lamellar microstructures, can be attained via two-step heat-treatments. Thereby, an increasing creep resistance is observed with decreasing lamellar interface spacing. Once lamellar structures reach nano-scaled dimensions, deformation mechanisms are altered dramatically. Hence, this study deals with a detailed characterization of the elevated temperature deformation phenomena prevailing in nano-lamellar TiAl alloys by the use of tensile creep experiments and mechanical spectroscopy. Upon creep exposure, microstructural changes occur in the lamellar structure, which are analyzed by the comparative utilization of X-ray diffraction, scanning and transmission electron microscopy as well as atom probe tomography. Creep activation parameters determined by mechanical characterization suggest the dominance of dislocation climb by a jog-pair formation process. The dislocations involved in deformation are, in nano-lamellar TiAl alloys, situated at the lamellar interfaces. During creep exposure the precipitation of β_o phase and ζ-silicide particles is observed emanating from the α_2 phase, which is due to the accumulation of Mo and Si at lamellar interfaces.

  20. Effects of Microalloying on the Microstructures and Mechanical Properties of Directionally Solidified Ni-33(at.%)Al-31Cr-3Mo Eutectic Alloys Investigated

    Science.gov (United States)

    Whittenberger, J. Daniel; Raj, Sai V.; Locci, Ivan E.; Salem, Jonathan A.

    2002-01-01

    Despite nickel aluminide (NiAl) alloys' attractive combination of oxidation and thermophysical properties, their development as replacements for superalloy airfoils in gas turbine engines has been largely limited by difficulties in developing alloys with an optimum combination of elevated-temperature creep resistance and room-temperature fracture toughness. Alternatively, research has focused on developing directionally solidified NiAl-based in situ eutectic composites composed of NiAl and (Cr,Mo) phases in order to obtain a desirable combination of properties a systematic investigation was undertaken at the NASA Glenn Research Center to examine the effects of small additions of 11 alloying elements (Co, Cu, Fe, Hf, Mn, Nb, Re, Si, Ta, Ti, and Zr) in amounts varying from 0.25 to 1.0 at.% on the elevated-temperature strength and room-temperature fracture toughness of directionally solidified Ni-33Al-31Cr-3Mo eutectic alloy. The alloys were grown at 12.7 mm/hr, where the unalloyed eutectic base alloy exhibited a planar eutectic microstructure. The different microstructures that formed because of these fifth-element additions are included in the table. The additions of these elements even in small amounts resulted in the formation of cellular microstructures, and in some cases, dendrites and third phases were observed. Most of these elemental additions did not improve either the elevated-temperature strength or the room-temperature fracture toughness over that of the base alloy. However, small improvements in the compression strength were observed between 1200 and 1400 K when 0.5 at.% Hf and 0.25 at.% Ti were added to the base alloy. The results of this study suggest that the microalloying of Ni-33Al-31Cr-3Mo will not significantly improve either its elevatedtemperature strength or its room-temperature fracture toughness. Thus, any improvements in these properties must be acquired by changing the processing conditions.

  1. Surface modification of 5083 Al alloy by electrical discharge alloying processing with a 75 mass% Si-Fe alloy electrode

    Energy Technology Data Exchange (ETDEWEB)

    Stambekova, Kuralay [Department of Materials Science and Engineering, National Chung Hsing University, 250 Kuo-Kuang Rd., Taichung 40227, Taiwan (China); Lin, Hung-Mao [Department of Mechanical Engineering, Far East University, No. 49, Zhonghua Rd., Xinshi Dist., Tainan City 74448, Taiwan (China); Uan, Jun-Yen, E-mail: jyuan@dragon.nchu.edu.tw [Department of Materials Science and Engineering, National Chung Hsing University, 250 Kuo-Kuang Rd., Taichung 40227, Taiwan (China)

    2012-03-01

    This study experimentally investigates the surface modification of 5083 Al alloy by the electrical discharge alloying (EDA) process with a Si-Fe alloy as an electrode. Samples were analyzed by transmission electron microscopy (TEM), scanning electron microscopy (SEM), micro-hardness and corrosion resistance tests. The micro-hardness of EDA alloyed layer was evidently higher than that of the base metal (5083 Al alloy). The TEM results show that the matrix of the alloyed layer has an amorphous-like structure; the matrix contains fine needle-like Si particles, block-like Si particles and nano-size Al{sub 4.5}FeSi and Al{sub 13}Fe{sub 4} particles. The TEM results support experimental results for the high hardness of the alloyed layer. Moreover, the EDA alloyed layer with composite microstructures has good corrosion resistance in NaCl aqueous solution.

  2. Thermal barrier coatings with a double-layer bond coat on Ni{sub 3}Al based single-crystal superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xin [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Beijing Institute of Aeronautical Materials, Department 5, P.O. Box 81-5, Beijing 100095 (China); Xu, Zhenhua; Mu, Rende [Beijing Institute of Aeronautical Materials, Department 5, P.O. Box 81-5, Beijing 100095 (China); He, Limin, E-mail: he_limin@yahoo.com [Beijing Institute of Aeronautical Materials, Department 5, P.O. Box 81-5, Beijing 100095 (China); Huang, Guanghong [Beijing Institute of Aeronautical Materials, Department 5, P.O. Box 81-5, Beijing 100095 (China); Cao, Xueqiang, E-mail: xcao@ciac.ac.cn [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

    2014-04-05

    Highlights: • Thermal barrier coatings with a double-layer bond coat of (Ni,Pt)Al and NiCrAlYSi. • Good adherence at all interfaces within TBC system. • The underlying (Ni,Pt)Al layer can supply abundant Al content for the upper NiCrAlYSi layer. • Crack nucleation, propagation and coalescence lead to the failure of coating. -- Abstract: Electron-beam physical vapor deposited thermal barrier coatings (TBCs) with a double-layer bond coat of (Ni,Pt)Al and NiCrAlYSi were prepared on a Ni{sub 3}Al based single-crystal superalloy. Phase and cross-sectional microstructure of the developed coatings were studied by using X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. The experimental results show good adherence at all interfaces within this system. Furthermore, oxidation resistance and elements interdiffusion behavior of the double-layer bond coat were also investigated. The double-layer bond coat system exhibits a better scale adherence than the single layer bond coat systems since the underlying (Ni,Pt)Al layer can supply abundant Al for the upper NiCrAlYSi layer. Finally, thermal cycling behavior of the double-layer bond coat TBC was evaluated and the failure mechanism was discussed. Crack nucleation, propagation and coalescence caused by TGO growth stress and the thermal expansion mismatch stress between TGO and bond coat can be mainly responsible for the spallation of this coating.

  3. Effect of a ductility layer on the tensile strength of TiAl-based multilayer composite sheets prepared by EB-PVD

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Rubing, E-mail: zrb86411680@126.com [Department of Mechanics, School of Civil Engineering, Beijing Jiaotong University, Beijing 100044 (China); Zhang, Yaoyao [Department of Mechanics, School of Civil Engineering, Beijing Jiaotong University, Beijing 100044 (China); Liu, Qiang [Beijing Institute of Astronautical Systems Engineering, Beijing 100076 (China); Chen, Guiqing [Center for Composite Materials, Harbin Institute of Technology, Harbin 150001 (China); Zhang, Deming [Beijing General Research Institute of Mining and Metallurgy, Beijing 100044 (China)

    2014-09-15

    TiAl/Nb and TiAl/NiCoCrAl laminate composite sheets with a thickness of 0.4–0.6 mm and dimensions of 150 mm × 100 mm were successfully fabricated by electron beam physical vapor deposition. The microstructures of the sheets were examined, and their mechanical properties were compared with those of TiAl monolithic sheet produced by electron beam physical vapor deposition. Tensile testing was performed at room temperature and 750 °C, and the fracture surfaces were examined by scanning electron microscopy. Among the three microlaminate sheets, the TiAl/NiCoCrAl micro-laminate sheet had the best comprehensive properties at room temperature, and the TiAl/Nb micro-laminate sheet showed the ideal high-temperature strength and plasticity at 750 °C. The result was discussed in terms of metal strengthening mechanism. - Highlights: • TiAl-based multilayer foils was fabricated successfully by using EB-PVD method; • The tensile properties and micro-fracture morphologies of the sheet were investigated; • The deformation behavior of the multilayer foils was discussed.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-07-04

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

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  6. Electron-beam welding of aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Brillant, Marcel; de Bony, Yves

    1980-08-15

    The objective of this article is to describe the status of the application of electron-beam welding to aluminum alloys. These alloys are widely employed in the aeronautics, space and nuclear industries.

  7. Thermodynamic Database for Zirconium Alloys

    International Nuclear Information System (INIS)

    Jerlerud Perez, Rosa

    2003-05-01

    For many decades zirconium alloys have been commonly used in the nuclear power industry as fuel cladding material. Besides their good corrosion resistance and acceptable mechanical properties the main reason of using these alloys is the low neutron absorption. Zirconium alloys are exposed to a very severe environment during the nuclear fission process and there is a demand for better design of this material. To meet this requirement a thermodynamic database is developed to support material designers. In this thesis some aspects about the development of a thermodynamic database for zirconium alloys are presented. A thermodynamic database represents an important facility in applying thermodynamic equilibrium calculations for a given material providing: 1) relevant information about the thermodynamic properties of the alloys e.g. enthalpies, activities, heat capacity, and 2) significant information for the manufacturing process e.g. heat treatment temperature. The basic information in the database is first the unary data, i.e. pure elements; those are taken from the compilation of the Scientific Group Thermodata Europe (SGTE) and then the binary and ternary systems. All phases present in those binary and ternary systems are described by means of the Gibbs energy dependence on composition and temperature. Many of those binary systems have been taken from published or unpublished works and others have been assessed in the present work. All the calculations have been made using Thermo C alc software and the representation of the Gibbs energy obtained by applying Calphad technique

  8. Carbon Alloys-Multi-functionalization

    Energy Technology Data Exchange (ETDEWEB)

    Yasuda, Eiichi [MSL, Tokyo Institute of Technology, Yokohama 226-8503 (Japan)], E-mail: yasuda.e.aa.@m.titech.ac.jp; Enami, Takashi; Hoteida, Nobuyuki [MSL, Tokyo Institute of Technology, Yokohama 226-8503 (Japan); Lanticse-Diaz, L.J. [University of the Philippines (Philippines); Tanabe, Yasuhiro [Nagoya University (Japan); Akatsu, Takashi [MSL, Tokyo Institute of Technology, Yokohama 226-8503 (Japan)

    2008-02-25

    Last decade after our proposal of the 'Carbon Alloys' concept, many different kinds of Carbon Alloys, such as carbon nanotubes, carbon nanofibers, graphene sheet with magnetism, semi-conducting BCN compounds, graphite intercalation compounds, exfoliated carbon fiber, etc. have been found and developed. To extend the concept further, it is important to make it into intelligent materials by incorporating multiple functions. One example of the multi-functionalization is the development of homo-atomic Carbon Alloys from glassy carbon (GC) that exhibits high electrical conductivity and low gas permeability after treatment at critical conditions. Glassy carbon underwent metamorphosis to graphite spheres at HIP condition, and improved resistance to oxidation after alloying with Ta. The other one is shape utilization of the nano-sized carbon by understanding the effect of its large surfaces or interfaces in nanotechnology treatment. Recently carbon nanofiber was produced by polymer blend technology (PB) which was proposed by Prof. A. Oya during the Carbon Alloy project and progressed into intelligent carbon nanofiber (CNF) materials. CNF is combined into the polymer composites which is a candidate material for the bipolar separator in fuel cell. The superior properties, i.e., high electrical conductivity, high modulus, high strength, etc., of the CNF is being utilized in the preparation of this polymer composite.

  9. Synthesis of Nb-18%Al alloy by mechanical alloying method

    International Nuclear Information System (INIS)

    Dymek, S.; Wrobel, M.; Dollar, M.

    1999-01-01

    The main goal of this study was attempt to employ by mechanical alloying to produce Nb-Al alloy. The Nb-rich alloy composition was selected in order to receive the ductile niobium solid solution (Nb ss ) phase in the final, equilibrium state. This ductile phase was believed to prevent crack propagation in the consolidated alloy and thus to improve its ductility and toughness. Elemental powders of niobium (99.8% pure and -325 mesh) and aluminium (99.9% pure and -325 mesh) were used as starting materials. These powders were mixed to give the nominal compositions od 82% Nb and 18% Al (atomic percent). Mechanical alloying was carried out in a Szegvari laboratory attritor mill in an argon atmosphere with the controlled oxygen level reduced to less than 10 ppm. The total milling time was 86 hours. During the course of milling powder samples were taken out after 5, 10 and 20 hours, which allowed characterization of the powder morphology and progress of the mechanical alloying process. The changes in particle morphology during milling were examined using a scanning electron microscope and the phase analysis was performed in a X-ray diffractometer with CoK α radiation. Initially, particles' size increased and their appearance changed from the regular to one of the flaky shape. X-ray diffraction patterns of examined powders as a function of milling time are presented. Peaks from Al, through much weaker than in the starting material, were still present after 5 hours of milling but disappeared completely after 10 hours of milling. With increasing milling time, the peaks became broader and their intensities decreased. Formation of amorphous phase was observed after 86 hours of milling. This was deducted from a diffuse halo observed at the 2Θ angle of about 27 o . Intermetallic phases Nb 3 Al and Nb 2 Al were found in the consolidated material only. (author)

  10. Synthesis and mechanical properties of bulk Al{sub 76}Ni{sub 8}Ti{sub 8}Zr{sub 4}Y{sub 4} alloy fabricated by consolidation of mechanically alloyed amorphous powders

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xinfu; Wang, Kun; Li, Zhendong; Wang, Xingfu; Wang, Dan; Han, Fusheng, E-mail: fshan@issp.ac.cn

    2015-05-25

    Graphical abstract: Different regions indentation morphologies under 50 g load consolidated at 723 K (left), nanohardness of the Al{sub 76}Ni{sub 8}Ti{sub 8}Zr{sub 4}Y{sub 4} alloy as a function consolidation temperature (right). It can be seen from the above figures that the consolidated sample presents white regions, and the microhardness in the white regions is a little lower than the matrix, which could be caused by the difference of the chemical composition and chemical bonding forces between them. Interestingly, the cracks were formed around the indentation periphery in the white regions, which are not shown in the matrix. The nanohardness of the bulk composites increased from 11.16 to 13.27 GPa with the consolidation temperature increasing, mechanical softening was also found in the present alloys. - Highlights: • Bulk amorphous–nanocrystalline Al-based alloys were prepared by HPS process. • The Vickers microhardness of bulk samples is in the range of 945–1177HV0.1. • The nanohardness agrees well with the Vickers hardness testing results. - Abstract: Mechanically alloyed amorphous Al{sub 76}Ni{sub 8}Ti{sub 8}Zr{sub 4}Y{sub 4} (at.%) alloy powder was consolidated by high-pressure sintering process. The influence of the consolidation temperature on the structure and mechanical properties of the consolidated bulk alloys was examined by X-ray diffraction (XRD), Optical microscopy (OM), Scanning electron microscopy (SEM), Vickers Hardness Tester and Nano Indenter. Structural investigations of the bulk materials revealed that most of the amorphous structure was retained after consolidation at 623 K, however, compaction at 723 K and 823 K caused crystallization of the amorphous phase with the appearance of white regions. The results also indicate that application of high pressure affected the crystallization products of the present alloy. Micro mechanical analysis showed that the microhardness of the bulk composites increased from 945HV{sub 0.1} to 1177HV

  11. Progress in development of iron base alloys

    International Nuclear Information System (INIS)

    Zackay, V.V.; Parker, E.R.

    1980-01-01

    The ways of development of new iron base high-strength alloys are considered. Perspectiveness of ferritic steel strengthening with intermetallides (TaFe 2 , for instance) is shown. Favourable combination of plasticity, strength and fracture toughness in nickel-free iron-manganese alloys (16-20%) is also pointed out. A strength level of alloyed maraging steels can be achieved by changes in chemical composition and by proper heat treatments of low- and medium-alloyed steels

  12. Fe-Cr-Ni system alloys

    International Nuclear Information System (INIS)

    Levin, F.L.

    1986-01-01

    Phase diagram of Fe-Cr-Ni system, which is the basic one for production of corrosion resistant alloys, is considered. Data on corrosion resistance of such alloys are correlated depending on a number of factors: quality and composition of modifying elements, corrosion medium, temperature, alloy structure, mechanical and thermal treatment. Grades of Fe-Ni-Cr alloys are presented, and fields of their application are pointed out

  13. Mechanical behaviour of aluminium-lithium alloys

    Indian Academy of Sciences (India)

    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 ...

  14. Corrosion Behaviour of New Zr Alloys

    DEFF Research Database (Denmark)

    Tolksdorf, E.

    1974-01-01

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

  15. Ti-Pt Alloys form mechanical milling

    CSIR Research Space (South Africa)

    Nxumalo, S

    2009-12-01

    Full Text Available C maximum in these alloys. A few researchers have studied the martensitic transformation in TiPt alloys using arc melted cast samples. In this work high temperature shape memory alloys are targeted using powder metallurgy as a processing route....

  16. Magnesium and related low alloys

    International Nuclear Information System (INIS)

    Bernard, J.; Caillat, R.; Darras, R.

    1959-01-01

    In the first part the authors examine the comparative corrosion of commercial magnesium, of a magnesium-zirconium alloy (0,4 per cent ≤ Zr ≤ 0,7 per cent) of a ternary magnesium-zinc-zirconium alloy (0,8 per cent ≤ Zn ≤ 1,2 per cent) and of english 'Magnox type' alloys, in dry carbon dioxide-free air, in damp carbon dioxide-free air, and in dry and damp carbon dioxide, at temperatures from 300 to 600 deg. C. In the second part the structural stability of these materials is studied after annealings, of 10 to 1000 hours at 300 to 450 deg. C. Variations in grain after these heat treatments and mechanical stretching properties at room temperature are presented. Finally various creep rate and life time diagrams are given for these materials, for temperatures ranging from 300 to 450 deg. C. (author) [fr

  17. Chloride removal from plutonium alloy

    International Nuclear Information System (INIS)

    Holcomb, H.P.

    1983-01-01

    SRP is evaluating a program to recover plutonium from a metallic alloy that will contain chloride salt impurities. Removal of chloride to sufficiently low levels to prevent damaging corrosion to canyon equipment is feasible as a head-end step following dissolution. Silver nitrate and mercurous nitrate were each successfully used in laboratory tests to remove chloride from simulated alloy dissolver solution containing plutonium. Levels less than 10 ppM chloride were achieved in the supernates over the precipitated and centrifuged insoluble salts. Also, less than 0.05% loss of plutonium in the +3, +4, or +6 oxidation states was incurred via precipitate carrying. These results provide impetus for further study and development of a plant-scale process to recover plutonium from metal alloy at SRP

  18. Structure, thermal and mechanical properties of in situ Al-based metal matrix composite reinforced with Al2O3 and TiC submicron particles

    International Nuclear Information System (INIS)

    Yu Peng; Mei Zhi; Tjong, S.C.

    2005-01-01

    We report herein the structure and characterization of in situ Al-based metal matrix composites (MMCs) prepared from the Al-10 wt.% TiO 2 and Al-10 wt.% TiO 2 -1.5 wt.% C systems via hot isostatic pressing (HIP) at 1000 deg C and 100 MPa. The structure, morphology and thermal behavior of HIPed samples were studied by means of the X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The results indicated that fined Al 2 O 3 particles and large intermetallic Al 3 Ti plates were in situ formed in the Al-10 wt.% TiO 2 sample during HIPing. However, the introduction of C to the Al-TiO 2 system was beneficial to eliminate large intermetallic Al 3 Ti plates. In this case, Al 2 O 3 and TiC submicron particles were in situ formed in the Al-10 wt.% TiO 2 -1.5 wt.% C sample. Three-point-bending test showed that the strength and the strain-at-break of the HIPed Al-10 wt.% TiO 2 -1.5 wt.% C sample were significantly higher than those of its Al-10 wt.% TiO 2 counterpart. The improvement was derived from the elimination of bulk Al 3 Ti intermetallic plates and from the formation of TiC submicron particles. DSC measurements and thermodynamic analyses were carried out to reveal the reaction formation mechanisms of in situ reinforcing phases. The DSC results generally correlated well with the theoretical predictions. Finally, the correlation between the structure-property relationships of in situ composites is discussed

  19. Alloy phase stability and design

    International Nuclear Information System (INIS)

    Stocks, G.M.; Pope, E.P.; Giamei, A.F.

    1991-01-01

    At the level of basic quantum theory the papers in this symposium reflect the great progress that has been made in understanding the physical properties of both ordered and disordered alloys based on Density Functional Theory (DFT). DFT provides a quantitative parameter-free (often referred to as first principles) theory of the ground state properties of these systems. This general approach has also been used in combination with classical elasticity and dislocation theory to provide the first quantitative understanding of some of the mechanical properties of intermetallic alloys. Recent advances have built on DFT theory to provide the first glimpses of a theory of the finite temperature phase stability of alloys. It is the strength of these first principles theories that the understanding of materials properties is in terms of the underlying electronic structure. At the level of atomistic simulation, based on semi-empirical potentials, again much progress has been made in understanding the properties of extended defects such as grain boundaries and dislocations. On the experimental front increasingly sophisticated tools are being brought to bear in order to understand both the underlying electronic structure and detailed atomic arrangements. This information, together with input from theory, is playing an increasing role in guiding alloy design efforts. At the more practical level a number of these sophisticated alloy design efforts have in recent years produced impressive results across a broad front. The properties of existing materials are continually being improved and new ones developed. Often this progress is based on a deeper understanding of the properties at the atomistic and electronic level. The design of new ordered intermetallic alloys that have reached or are reaching commercialization represents one of the major achievements of this investment of intellectual resources

  20. Theoretical studies of metallic alloys

    International Nuclear Information System (INIS)

    Faulkner, J.S.; Wille, L.T.

    1991-07-01

    A new method to predict and understand the structure and phase stability of solid-solution alloys from a knowledge only of the atomic numbers of the constituent atoms is being developed. The coherent potential approximation will be used to obtain the electronic contribution to the energy and the Monte Carlo method of statistical mechanics will be used for the thermodynamic part of the calculation. An improved coherent potential approximation will be developed by combining the standard approach with the quadratic KKR (QKKR) band theory method. This will make it easier to predict the properties of alloys from first principles. The QKKR method will be developed further

  1. PROCESS OF DISSOLVING ZIRCONIUM ALLOYS

    Science.gov (United States)

    Shor, R.S.; Vogler, S.

    1958-01-21

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

  2. Hydrogen effects in aluminum alloys

    International Nuclear Information System (INIS)

    Louthan, M.R. Jr.; Caskey, G.R. Jr.; Dexter, A.H.

    1976-01-01

    The permeability of six commercial aluminum alloys to deuterium and tritium was determined by several techniques. Surface films inhibited permeation under most conditions; however, contact with lithium deuteride during the tests minimized the surface effects. Under these conditions phi/sub D 2 / = 1.9 x 10 -2 exp (--22,400/RT) cc (NTP)atm/sup -- 1 / 2 / s -1 cm -1 . The six alloys were also tested before, during, and after exposure to high pressure hydrogen, and no hydrogen-induced effects on the tensile properties were observed

  3. Phosphorus containing sintered alloys (review)

    International Nuclear Information System (INIS)

    Muchnik, S.V.

    1984-01-01

    Phosphorus additives are considered for their effect on the properties of sintered alloys of different applications: structural, antifriction, friction, magnetic, hard, superhard, heavy etc. Data are presented on compositions and properties of phosphorus-containing materials produced by the powder metallurgy method. Phosphorus is shown to be an effective activator of sintering in some cases. When its concentration in the material is optimal it imparts the material such properties as strength, viscosity, hardness, wear resistance. Problems concerning powder metallurgy of amorphous phosphorus-containing alloys are reported

  4. Hot workability of aluminium alloys

    International Nuclear Information System (INIS)

    Yoo, Yeon Chul; Oh, Kyung Jin

    1986-01-01

    Hot Workability of aluminium alloys, 2024, 6061 and 7075, has been studied by hot torsion tests at temperatures from 320 to 515 deg C and at strain rates from 1.26 x 10 -3 to 5.71 x 10 -3 sec -1 . Hot working condition of these aluminium alloys was determined quantitatively from the constitutive equations obtained from flow stress curves in torsion. Experimental data of the logarith of the Zener-Hollomonn parameter showed good linear relationships to the logarith of sinh(ασ-bar)

  5. [Microbiological corrosion of aluminum alloys].

    Science.gov (United States)

    Smirnov, V F; Belov, D V; Sokolova, T N; Kuzina, O V; Kartashov, V R

    2008-01-01

    Biological corrosion of ADO quality aluminum and aluminum-based construction materials (alloys V65, D16, and D16T) was studied. Thirteen microscopic fungus species and six bacterial species proved to be able to attack aluminum and its alloys. It was found that biocorrosion of metals by microscopic fungi and bacteria was mediated by certain exometabolites. Experiments on biocorrosion of the materials by the microscopic fungus Alternaria alternata, the most active biodegrader, demonstrated that the micromycete attack started with the appearance of exudate with pH 8-9 on end faces of the samples.

  6. Mechanical properties of ordered alloys

    International Nuclear Information System (INIS)

    Kroupa, F.

    1977-06-01

    A survey is given of the metallophysical fundamentals of the mechanical properties of ordered two-phase alloys. Alloys of this type have a superlattice structure in a substitution mixed crystal. Ordering is achieved by slow cooling or by annealing below the critical temperature, during which ordering domains (antiphase domains) are formed. At a high degree of ordering, the dislocations are concentrated to form pairs, so-called super-dislocations. The mechanical properties may be selectively changed by varying different parameters (size of the ordering domains, degree of ordering, energy of the antiphase boundaries) by a special composition and heat treatment.(GSC) [de

  7. Tribometric Optical and Electrical Properties of Sputtered Quasicrystalline

    National Research Council Canada - National Science Library

    Ketola, Kurt

    2002-01-01

    .... The coefficient of friction (COF) is measured as a function of temperature between room temperature and 200 degrees C in vacuum as the flat oscillates relative to the pin at an average sliding speed of 3-4 mm/sec...

  8. Stress distribution in quasi-crystalline granular piles

    NARCIS (Netherlands)

    Trigger, S.A.; Heijst, van G.J.F.; Krasnopolskaya, T.S.; Schram, P.P.J.M.

    2001-01-01

    The main goal of this paper is a rigorous consideration of the stress problem in some simple models of granular piles. Discrete models are considered and the transition to the continuous description is accomplished in order to find the coarse-grained average stress. Some phenomenological rules are

  9. Evidence of a stable binary CdCa quasicrystalline phase

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Jensen, C.H.; Rasmussen, A.R.

    2001-01-01

    Quasicrystals with a primitive icosahedral structure and a quasilattice constant of 5.1215 Angstrom have been synthesized in a binary Cd-Ca system. The thermal stability of the quasicrystal has been investigated by in situ high-temperature x-ray powder diffraction using synchrotron radiation. It ....... It is demonstrated that the binary CdCa quasicrystal is thermodynamic stable up to its melting temperature. The linear thermal expansion coefficient of the quasicrystal is 2.765x10(-5) K-1. (C) 2001 American Institute of Physics.......Quasicrystals with a primitive icosahedral structure and a quasilattice constant of 5.1215 Angstrom have been synthesized in a binary Cd-Ca system. The thermal stability of the quasicrystal has been investigated by in situ high-temperature x-ray powder diffraction using synchrotron radiation...

  10. Imparting passivity to vapor deposited magnesium alloys

    Science.gov (United States)

    Wolfe, Ryan C.

    Magnesium has the lowest density of all structural metals. Utilization of low density materials is advantageous from a design standpoint, because lower weight translates into improved performance of engineered products (i.e., notebook computers are more portable, vehicles achieve better gas mileage, and aircraft can carry more payload). Despite their low density and high strength to weight ratio, however, the widespread implementation of magnesium alloys is currently hindered by their relatively poor corrosion resistance. The objective of this research dissertation is to develop a scientific basis for the creation of a corrosion resistant magnesium alloy. The corrosion resistance of magnesium alloys is affected by several interrelated factors. Among these are alloying, microstructure, impurities, galvanic corrosion effects, and service conditions, among others. Alloying and modification of the microstructure are primary approaches to controlling corrosion. Furthermore, nonequilibrium alloying of magnesium via physical vapor deposition allows for the formation of single-phase magnesium alloys with supersaturated concentrations of passivity-enhancing elements. The microstructure and surface morphology is also modifiable during physical vapor deposition through the variation of evaporation power, pressure, temperature, ion bombardment, and the source-to-substrate distance. Aluminum, titanium, yttrium, and zirconium were initially chosen as candidates likely to impart passivity on vapor deposited magnesium alloys. Prior to this research, alloys of this type have never before been produced, much less studied. All of these metals were observed to afford some degree of corrosion resistance to magnesium. Due to the especially promising results from nonequilibrium alloying of magnesium with yttrium and titanium, the ternary magnesium-yttrium-titanium system was investigated in depth. While all of the alloys are lustrous, surface morphology is observed under the scanning

  11. ZIRCONIUM-TITANIUM-BERYLLIUM BRAZING ALLOY

    Science.gov (United States)

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

    1962-06-12

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

  12. An introduction to surface alloying of metals

    CERN Document Server

    Hosmani, Santosh S; Goyal, Rajendra Kumar

    2014-01-01

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

  13. Protective claddings for high strength chromium alloys

    Science.gov (United States)

    Collins, J. F.

    1971-01-01

    The application of a Cr-Y-Hf-Th alloy as a protective cladding for a high strength chromium alloy was investigated for its effectiveness in inhibiting nitrogen embrittlement of a core alloy. Cladding was accomplished by a combination of hot gas pressure bonding and roll cladding techniques. Based on bend DBTT, the cladding alloy was effective in inhibiting nitrogen embrittlement of the chromium core alloy for up to 720 ks (200hours) in air at 1422 K (2100 F). A significant increase in the bend DBTT occurred with longer time exposures at 1422 K or short time exposures at 1589 K (2400 F).

  14. Investigating aluminum alloy reinforced by graphene nanoflakes

    Energy Technology Data Exchange (ETDEWEB)

    Yan, S.J., E-mail: shaojiuyan@126.com [Beijing Institute of Aeronautical Materials, Beijing 100095 (China); Dai, S.L.; Zhang, X.Y.; Yang, C.; Hong, Q.H.; Chen, J.Z. [Beijing Institute of Aeronautical Materials, Beijing 100095 (China); Lin, Z.M. [Aviation Industry Corporation of China, Beijing 100022 (China)

    2014-08-26

    As one of the most important engineering materials, aluminum alloys have been widely applied in many fields. However, the requirement of enhancing their mechanical properties without sacrificing the ductility is always a challenge in the development of aluminum alloys. Thanks to the excellent physical and mechanical properties, graphene nanoflakes (GNFs) have been applied as promising reinforcing elements in various engineering materials, including polymers and ceramics. However, the investigation of GNFs as reinforcement phase in metals or alloys, especially in aluminum alloys, is still very limited. In this study, the aluminum alloy reinforced by GNFs was successfully prepared via powder metallurgy approach. The GNFs were mixed with aluminum alloy powders through ball milling and followed by hot isostatic pressing. The green body was then hot extruded to obtain the final GNFs reinforced aluminum alloy nanocomposite. The scanning electron microscopy and transmission electron microscope analysis show that GNFs were well dispersed in the aluminum alloy matrix and no chemical reactions were observed at the interfaces between the GNFs and aluminum alloy matrix. The mechanical properties' testing results show that with increasing filling content of GNFs, both tensile and yield strengths were remarkably increased without losing the ductility performance. These results not only provided a pathway to achieve the goal of preparing high strength aluminum alloys with excellent ductilitybut they also shed light on the development of other metal alloys reinforced by GNFs.

  15. Environmental fatigue in aluminum-lithium alloys

    Science.gov (United States)

    Piascik, Robert S.

    1992-01-01

    Aluminum-lithium alloys exhibit similar environmental fatigue crack growth characteristics compared to conventional 2000 series alloys and are more resistant to environmental fatigue compared to 7000 series alloys. The superior fatigue crack growth behavior of Al-Li alloys 2090, 2091, 8090, and 8091 is due to crack closure caused by tortuous crack path morphology and crack surface corrosion products. At high R and reduced closure, chemical environment effects are pronounced resulting in accelerated near threshold da/dN. The beneficial effects of crack closure are minimized for small cracks resulting in rapid growth rates. Limited data suggest that the 'chemically small crack' effect, observed in other alloy system, is not pronounced in Al-Li alloys. Modeling of environmental fatigue in Al-Li-Cu alloys related accelerated fatigue crack growth in moist air and salt water to hydrogen embrittlement.

  16. Applications of shape memory alloys in Japan

    International Nuclear Information System (INIS)

    Asai, M.; Suzuki, Y.

    2000-01-01

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

  17. Requirements of titanium alloys for aeronautical industry

    Science.gov (United States)

    Ghiban, Brânduşa; Bran, Dragoş-Teodor; Elefterie, Cornelia Florina

    2018-02-01

    The project presents the requirements imposed for aeronatical components made from Titanium based alloys. Asignificant portion of the aircraft pylons are manufactured from Titanium alloys. Strength, weight, and reliability are the primary factors to consider in aircraft structures. These factors determine the requirements to be met by any material used to construct or repair the aircraft. Many forces and structural stresses act on an aircraft when it is flying and when it is static and this thesis describes environmental factors, conditions of external aggression, mechanical characteristics and loadings that must be satisfied simultaneously by a Ti-based alloy, compared to other classes of aviation alloys (as egg. Inconel super alloys, Aluminum alloys). For this alloy class, the requirements are regarding strength to weight ratio, reliability, corrosion resistance, thermal expansion and so on. These characteristics additionally continue to provide new opportunities for advanced manufacturing methods.

  18. Aeronautical Industry Requirements for Titanium Alloys

    Science.gov (United States)

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

    2017-06-01

    The project presents the requirements imposed for aviation components made from Titanium based alloys. A significant portion of the aircraft pylons are manufactured from Titanium alloys. Strength, weight, and reliability are the primary factors to consider in aircraft structures. These factors determine the requirements to be met by any material used to construct or repair the aircraft. Many forces and structural stresses act on an aircraft when it is flying and when it is static and this thesis describes environmental factors, conditions of external aggression, mechanical characteristics and loadings that must be satisfied simultaneously by a Ti-based alloy, compared to other classes of aviation alloys (as egg. Inconel super alloys, Aluminum alloys).For this alloy class, the requirements are regarding strength to weight ratio, reliability, corrosion resistance, thermal expansion and so on. These characteristics additionally continue to provide new opportunities for advanced manufacturing methods.

  19. Passive Corrosion Behavior of Alloy 22

    International Nuclear Information System (INIS)

    R.B. Rebak; J.H. Payer

    2006-01-01

    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

  20. Irradiation effects in magnesium and aluminium alloys

    International Nuclear Information System (INIS)

    Sturcken, E.F.

    1979-01-01

    Effects of neutron irradiation on microstructure, mechanical properties and swelling of several magnesium and aluminium alloys were studied. The neutron fluences of 2-3 X 10 22 n/cm 2 , >0.2 MeV produced displacement doses of 20 to 45 displacements per atom (dpa). Ductility of the magnesium alloys was severely reduced by irradiation induced recrystallization and precipitation of various forms. Precipitation of transmuted silicon occurred in the aluminium alloys. However, the effect on ductility was much less than for the magnesium alloys. The magnesium and aluminium alloys had excellent resistance to swelling: The best magnesium alloy was Mg/3.0 wt% Al/0.19 wt% Ca; its density decreased by only 0.13%. The best aluminium alloy was 6063, with a density decrease of 0.22%. (Auth.)

  1. Nickel, cobalt, and their alloys

    CERN Document Server

    2000-01-01

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

  2. Heat treatment of nickel alloys

    International Nuclear Information System (INIS)

    Smith, D.F. Jr.; Clatworthy, E.F.

    1975-01-01

    A heat treating process is described that can be used to produce desired combinations of strength, ductility, and fabricability characteristics in heat resistant age-hardenable alloys having precipitation-hardening amounts of niobium, titanium, and/or tantalum in a nickel-containing matrix. (U.S.)

  3. Electroplated zinc-cobalt alloy

    International Nuclear Information System (INIS)

    Carpenter, D.E.O.S.; Farr, J.P.G.

    2005-01-01

    Recent work on the deposition and use of ectrodeposited zinc-cobalt alloys is surveyed. Alloys containing lower of Nuclear quantities of cobalt are potentially more useful. The structures of the deposits is related to their chemical and mechanical properties. The inclusion of oxide and its role in the deposition mechanism may be significant. Chemical and engineering properties relate to the metallurgical structure of the alloys, which derives from the mechanism of deposition. The inclusion of oxides and hydroxides in the electroplate may provide evidence for this mechanism. Electrochemical impedance measurements have been made at significant deposition potentials, in alkaline electrolytes. These reveal a complex electrode behaviour which depends not only on the electrode potential but on the Co content of the electrolyte. For the relevant range of cathodic potential zinc-cobalt alloy electrodeposition occurs through a stratified interface. The formation of an absorbed layer ZnOH/sup +/ is the initial step, this inhibits the deposition of cobalt at low cathodic potentials, so explaining its 'anomalous deposition'. A porous layer of zinc forms on the adsorbed ZnOH/sup +/ at underpotential. As the potential becomes more cathodic, cobalt co- deposits from its electrolytic complex forming a metallic solid solution of Co in Zn. In electrolytes containing a high concentration of cobalt a mixed entity (ZnCo)/sub +/ is assumed to adsorb at the cathode from which a CoZn intermetallic deposits. (author)

  4. Research on modulated structure alloys

    International Nuclear Information System (INIS)

    Tsujimoto, Tokuzo; Saito, Kazuo; Hashimoto, Kenki

    1982-01-01

    Research was carried out for the purposes of clarifying the cause of modulated structure formation, developing the structure control method utilizing modulated structure and clarifying the suitability of modulated structure alloys as radiation damage-resisting materials. The research on structure control method encountered a difficulty in the analysis of experimental results, bu the following results were obtained in the other items. The method of solving a diffusion equation including a nonlinear term was found in course of the clarification of the cause of modulated structure formation. As a means of detecting faint unevenness in solid solution, of which the deviation of composition is a few %, the structure analysis method utilizing magnetic property was developed. This method was applied to Ni-9.6 at.% Ti alloy, and the process of expanding amplitude in composition variation in spinodal decomposition and the formation of solute atomshort region at the time of nucleation-growth were confirmed. Utilizing the high energy electron beam generated in a superhigh voltage electron microscope, electron beam irradiation experiment was carried out on precipitation hardening alloys with modulated structure. As the result, it was found that in Ni-Ti alloy, the amount of void swelling resistance showed the change with the increase of modulated structure period. (Kako, I.)

  5. Palladium alloys for hydrogen diffusion

    International Nuclear Information System (INIS)

    1977-01-01

    A palladium-base alloy with tin and/or a silicon addition and its use in the production of hydrogen from water via a cycle of chemical reactions, of which the decomposition of HI into H 2 and I 2 is the most important, is described

  6. Introduction to hydrogen in alloys

    International Nuclear Information System (INIS)

    Westlake, D.G.

    1980-01-01

    Substitutional alloys, both those that form hydrides and those that do not, are discussed, but with more emphasis on the former than the latter. This overview includes the following closely related subjects: (1) the significant effects of substitutional solutes on the pressure-composition-temperature (PCT) equilibria of metal-hydrogen systems, (2) the changes in thermodynamic properties resulting from differences in atom size and from modifications of electronic structure, (3) attractive and repulsive interactions between H and solute atoms and the effects of such interactions on the pressure dependent solubility for H, (4) H trapping in alloys of Group V metals and its effect on the terminal solubility for H (TSH), (5) some other mechanisms invoked to explain the enhancement (due to alloying) of the (TSH) in Group V metals, and (6) H-impurity complexes in alloys of the metals Ni, Co, and Fe. Some results showing that an enhanced TSH may ameliorate the resistance of a metal to hydrogen embrittlement are presented

  7. Iron-nickel-chromium alloys

    International Nuclear Information System (INIS)

    Karenko, M.K.

    1981-01-01

    A specification is given for iron-nickel-chromium age-hardenable alloys suitable for use in fast breeder reactor ducts and cladding, which utilize the gamma-double prime strengthening phase and are characterized in having a delta or eta phase distributed at or near grain boundaries. A range of compositions is given. (author)

  8. Electroless alloy/composite coatings

    Indian Academy of Sciences (India)

    The market for these coatings is expanding fast as the potential applications are on the rise. In the present article, an attempt has been made to review different electroless alloy/composite coatings with respect to bath types and their composition, properties and applications. Different characterisation studies have been ...

  9. The welding of alloy 800

    International Nuclear Information System (INIS)

    Ward, M.; Norman, P.L.

    1975-01-01

    This paper reviews the technical literature published on the welding of alloy 800. Much of this work has been carried out using the Varestraint and Gleeble tests to investigate the susceptibility of the alloy and of high nickel consumables to hot-cracking. Inspite of much reported work, it is pointed out that many years of experience in the use of alloy 800 shows it to be readily weldable without any major problems occurring due to hot-cracking. The elements investigated include titanium, aluminium, sulphur, phosphorus and carbon, and the effects of these elements are discuused in terms of their effects on the hot-ductility curves obtained by Gleeble testing. Conclusions reached by various researchers state that the individual effects of the above five elements may be masked by other unknown factors. It is concluded that with correct welding procedures alloy 800 can be welded without cracking problems even with high heat input welding processes using either high-nickel filler wires or a matching electrode. Matching composition filler wires have been used with success but none are at present available commercially. (author)

  10. Hydrostatic extrusion of magnesium alloys

    NARCIS (Netherlands)

    Sillekens, W.H.; Bohlen, J.

    2012-01-01

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

  11. Studies on neutron irradiation effects of iron alloys and nickel-base heat resistant alloys

    International Nuclear Information System (INIS)

    Watanabe, Katsutoshi

    1987-09-01

    The present paper describes the results of neutron irradiation effects on iron alloys and nickel-base heat resistant alloys. As for the iron alloys, irradiation hardening and embrittlement were investigated using internal friction measurement, electron microscopy and tensile testings. The role of alloying elements was also investigated to understand the irradiation behavior of iron alloys. The essential factors affecting irradiation hardening and embrittlement were thus clarified. On the other hand, postirradiation tensile and creep properties were measured of Hastelloy X alloy. Irradiation behavior at elevated temperatures is discussed. (author)

  12. The effect of location on the microstructure and mechanical properties of titanium aluminides produced by additive layer manufacturing using in-situ alloying and gas tungsten arc welding

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Yan; Cuiuri, Dominic; Hoye, Nicholas; Li, Huijun; Pan, Zengxi, E-mail: zengxi@uow.edu.au

    2015-04-17

    An innovative and low cost additive layer manufacturing (ALM) process is used to produce γ-TiAl based alloy wall components. Gas tungsten arc welding (GTAW) provides the heat source for this new approach, combined with in-situ alloying through separate feeding of commercially pure Ti and Al wires into the weld pool. This paper investigates the morphology, microstructure and mechanical properties of the additively manufactured TiAl material, and how these are affected by the location within the manufactured component. The typical additively layer manufactured morphology exhibits epitaxial growth of columnar grains and several layer bands. The fabricated γ-TiAl based alloy consists of comparatively large α{sub 2} grains in the near-substrate region, fully lamellar colonies with various sizes and interdendritic γ structure in the intermediate layer bands, followed by fine dendrites and interdendritic γ phases in the top region. Microhardness measurements and tensile testing results indicated relatively homogeneous mechanical characteristics throughout the deposited material. The exception to this homogeneity occurs in the near-substrate region immediately adjacent to the pure Ti substrate used in these experiments, where the alloying process is not as well controlled as in the higher regions. The tensile properties are also different for the vertical (build) direction and horizontal (travel) direction because of the differing microstructure in each direction. The microstructure variation and strengthening mechanisms resulting from the new manufacturing approach are analysed in detail. The results demonstrate the potential to produce full density titanium aluminide components directly using the new additive layer manufacturing method.

  13. The effect of location on the microstructure and mechanical properties of titanium aluminides produced by additive layer manufacturing using in-situ alloying and gas tungsten arc welding

    International Nuclear Information System (INIS)

    Ma, Yan; Cuiuri, Dominic; Hoye, Nicholas; Li, Huijun; Pan, Zengxi

    2015-01-01

    An innovative and low cost additive layer manufacturing (ALM) process is used to produce γ-TiAl based alloy wall components. Gas tungsten arc welding (GTAW) provides the heat source for this new approach, combined with in-situ alloying through separate feeding of commercially pure Ti and Al wires into the weld pool. This paper investigates the morphology, microstructure and mechanical properties of the additively manufactured TiAl material, and how these are affected by the location within the manufactured component. The typical additively layer manufactured morphology exhibits epitaxial growth of columnar grains and several layer bands. The fabricated γ-TiAl based alloy consists of comparatively large α 2 grains in the near-substrate region, fully lamellar colonies with various sizes and interdendritic γ structure in the intermediate layer bands, followed by fine dendrites and interdendritic γ phases in the top region. Microhardness measurements and tensile testing results indicated relatively homogeneous mechanical characteristics throughout the deposited material. The exception to this homogeneity occurs in the near-substrate region immediately adjacent to the pure Ti substrate used in these experiments, where the alloying process is not as well controlled as in the higher regions. The tensile properties are also different for the vertical (build) direction and horizontal (travel) direction because of the differing microstructure in each direction. The microstructure variation and strengthening mechanisms resulting from the new manufacturing approach are analysed in detail. The results demonstrate the potential to produce full density titanium aluminide components directly using the new additive layer manufacturing method

  14. Oxide characterization and hydrogen behaviors of Zr-based alloys

    International Nuclear Information System (INIS)

    Kim, Y. S.; Kim, D. J.; Kwon, S. H.; Lee, H. S.; Oh, S. J.; Yim, B. J.; Son, S. B.; Yun, S. P.

    2006-03-01

    The work scope and contents of the research are as follows : basic properties of zirconium alloys, hydrogen pick-up mechanism of zirconium alloy, effects of hydride on the corrosion behaviors of zirconium alloys, estimation on stress of oxide layer in the zirconium alloy, microstructure and characteristic of oxide in pre-hydrided zirconium alloys

  15. TEM characterization of plate-shaped L12-(Al,Ag)3Ti precipitates in a Ag-modified TiAl based intermetallics

    International Nuclear Information System (INIS)

    Yuan, Y.; Liu, H.W.; Zhao, X.N.; Meng, X.K.; Liu, Z.G.

    2006-01-01

    L1 2 -(Al,Ag) 3 Ti phase in a L1 0 -TiAl(Ag) intermetallic compound with a nominal composition of Ti-54 at.% Al-4 at.% Ag has been studied by transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray (EDX). TEM observations revealed that the alloy aged at 1273 K consists of L1 0 phase and L1 2 phase. The compositions of L1 2 phase and the matrix have been determined. The habit plane of L1 2 phase was analyzed by trace line method. It was revealed that the habit plane changed to one of {1 1 2) planes compared with our previous result. The semi-coherent interface was formed between L1 0 phase and L1 2 phase. HRTEM characterized the interface structure directly. The dislocation loops and ledges at the interphase boundary were observed. The results were discussed in terms of the competition between elastic strain and interfacial energy, ledge mechanism of phase transformation caused by long-range diffusion of the atoms

  16. Composites Strengthened with Graphene Platelets and Formed in Semisolid State Based on α and α/β MgLiAl Alloys

    Science.gov (United States)

    Dutkiewicz, Jan; Rogal, Łukasz; Fima, Przemyslaw; Ozga, Piotr

    2018-05-01

    MgLiAl base composites strengthened with graphene platelets were prepared by semisolid processing of ball-milled alloy chips with 2% of graphene platelets. Composites strengthened with graphene platelets show higher hardness and yield stress than the cast alloys, i.e., 160 MPa as compared to 90 MPa for as-cast alloy MgLi9Al1.5. Mechanical properties for MgLiAl-based composites were similar or higher than for composites based on conventional AZ91 or WE43 alloys. The strengthening however was not only due to the presence of graphene, but also phases resulting from the reaction between carbon and lithium, i.e., Li2C2 carbide. Graphene platelets were located at globules boundaries resulting from semisolid processing for all investigated composites. Graphene platelets were in agglomerates forming continuous layers at grain boundaries in the composite based on the alloy MgLi4.5Al1.5. The shape of agglomerates was more complex and wavy in the composite based on MgLi9Al1.5 alloy most probably due to lithium-graphene reaction. Electron diffraction from the two-phase region α + β in MgLi9Al1.5 indicated that [001]α and [110]β directions are rotated about 4° from the ideal relationship [001] hex || [110] bcc phases. It showed higher lattice rotation than in earlier studies what is most probably caused by lattice slip and rotation during semisolid pressing causing substantial deformation particularly within the β phase. Raman spectroscopy studies confirmed the presence of graphene platelets within agglomerates and in addition the presence mainly of Li2C2 carbides in composites based on MgLi4.5Al1.5 and Mg9Li1.5Al alloys. From the character of Raman spectra refinement of graphene platelets was found in comparison with their initial size. The graphene areas without carbides contain graphene nanoplatelets with lateral dimension close to initial graphene sample. Electron diffraction allowed to confirm the presence of Li2C2 carbide at the surface of agglomerates found from

  17. Progressive degradation of alloy 690 and the development of a significant improvement in alloy 800CR

    International Nuclear Information System (INIS)

    Staehle, Roger W.; Arioka, Koji; Tapping, Robert

    2015-01-01

    The present most widely used alloys for tubing in steam generators and structural materials in water cooled reactors are Alloy 690 and Alloy 800. However, both alloys, while improved over Alloy 600 may not meet the needs of longer range applications in the range of 80-100 years. Alloy 690 sustains damage resulting from the formation of cavities at grain boundaries which eventually cover about 50% of the area of the grain boundaries with the remainder covering being covered with carbides. The cavities seem to nucleate on the carbides leaving the grain boundaries a structure of cavities and carbides. Such a structure will lead the Alloy 690 to fail completely. Normal Alloy 800 does not produce such cavities and probably retains a large amount of its corrosion resistance but does sustain progressive SCC at low rate. A new alloy, 800CR, has been developed in a collaboration among Arioka, Tapping, and Staehle. This alloy is based on a Cr composition of 23.5-27% with the remainder retaining the previous Alloy 800 composition. 800CR sustains a crack velocity about 100 times less than Alloy 690 and a negligible rate of initiation. The 800CR, alloy is now seeking a patent. (authors)

  18. Phase formation in multicomponent monotectic aluminium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Mirkovic, Djordje; Groebner, Joachim; Schmid-Fetzer, Rainer [Institute of Metallurgy, Clausthal University of Technology (Germany)

    2008-07-01

    Alloys with a miscibility gap in the liquid state are potential materials for advanced bearings in automotive and other applications. While binary alloys, such as Al-Pb or Al-Bi, are well known, the information available for ternary monotectic Al-alloys is scarce. However, the phase formation in multicomponent alloys is not only more challenging from a scientific aspect, it is also a prerequisite for a focused development of advanced alloys. This motivated our detailed study of monotectic Al-Bi-Cu-Sn alloys including both experimental and computational thermodynamic methods. Based on the initially established systematic classification of monotectic ternary Al-alloys, the first promising monotectic reaction was observed in the ternary Al-Bi-Zn system. Further ternary systems Al-Cu-Sn, Al-Bi-Sn, Al-Bi-Cu and Bi-Cu-Sn were investigated as basis for quaternary Al-Bi-Cu-Sn alloys. Experimental investigations of phase equilibria, enthalpies and solidification microstructures were combined with thermodynamic modeling. The results demonstrate that the developed precise thermodynamic description is vital to reveal the distinct multicomponent monotectic features of pertinent phase diagrams. The solidification paths of ternary monotectic alloy systems, Al-Bi-Zn, Al-Sn-Cu and Al-Bi-Cu, were also studied using thermodynamic calculations, revealing specific details of phase formation during solidification of selected alloys.

  19. Design of high-temperature high-strength Al-Ti-V-Zr alloys

    International Nuclear Information System (INIS)

    Lee, H.M.

    1990-01-01

    This paper reports that it seems plausible to develop high-strength Al-base alloys useful up to 698K in view of the behavior of nickel base superalloys which resist degradation of mechanical properties to 75 pct of their absolute melting temperature. For high temperature Al alloys, the dispersed hardening phase must not undergo phase transformation to an undesirable phase during long time exposure at the temperature of interest. An additional factor to be considered is the stability of the hardening phase with respect to Ostwald ripening. This coarsening resistance is necessary so that the required strength level can be maintained after the long-time service at high temperatures. The equilibrium crystal structures of Al 3 Ti, Al 3 V and Al 3 Zr are tetragonal D0 22 , D0 22 and D0 23 , respectively. At the temperatures of interest, around 698K, vanadium and titanium are mutually substitutable in the form of Al 3 (Ti, V). Much of titanium and vanadium can be substituted for zirconium in the D0 23 - type Al 3 Zr compound, creating Al 3 (Ti, Zr) and Al 3 (V, Zr), respectively. In particular, it has been reported that fcc L1 2 -structured Al 3 M dispersoids form in the rapidly solidified Al-V-Zr and Al-Ti-Zr systems and both L1 2 and D0 23 -structured Al 3 M phases showed slow coarsening kinetics

  20. Fatigue-crack propagation in gamma-based titanium aluminide alloys at large and small crack sizes

    International Nuclear Information System (INIS)

    Kruzic, J.J.; Campbell, J.P.; Ritchie, R.O.

    1999-01-01

    Most evaluations of the fracture and fatigue-crack propagation properties of γ+α 2 titanium aluminide alloys to date have been performed using standard large-crack samples, e.g., compact-tension specimens containing crack sizes which are on the order of tens of millimeters, i.e., large compared to microstructural dimensions. However, these alloys have been targeted for applications, such as blades in gas-turbine engines, where relevant crack sizes are much smaller ( 5 mm) and (c ≅ 25--300 microm) cracks in a γ-TiAl based alloy, of composition Ti-47Al-2Nb-2Cr-0.2B (at.%), specifically for duplex (average grain size approximately17 microm) and refined lamellar (average colony size ≅150 microm) microstructures. It is found that, whereas the lamellar microstructure displays far superior fracture toughness and fatigue-crack growth resistance in the presence of large cracks, in small-crack testing the duplex microstructure exhibits a better combination of properties. The reasons for such contrasting behavior are examined in terms of the intrinsic and extrinsic (i.e., crack bridging) contributions to cyclic crack advance

  1. Corrosion-electrochemical behaviour and mechanical properties ofaluminium alloy-321, alloyed by barium

    International Nuclear Information System (INIS)

    Ganiev, I.; Mukhiddinov, G.N.; Kargapolova, T.V.; Mirsaidov, U.

    1995-01-01

    The purpose of present work is studying of influence of barium additionson electrochemical corrosion of casting aluminium-copper alloy Al-321,containing as base alloying components copper, chromium, manganese, titanium,zirconium, cadmium

  2. Investigation on mechanical alloying process for v-cr-ti alloys

    International Nuclear Information System (INIS)

    Stanciulescu, M.; Carlan, P.; Mihalache, M.; Bucsa, G.; Abrudeanu, M.; Galateanu, A.

    2015-01-01

    Mechanical alloying (MA) is an efficient approach for fabricating oxide-dispersion alloys and structural materials including vanadium alloys for fusion and fission application. Dissolution behaviour of the alloying elements is a key issue for optimizing the mechanical alloying process in fabricating vanadium alloys. This paper studies the MA process of V-4wt.%Cr-4wt.%Ti alloy. The outcomes of the MA powders in a planetary ball mill are reported in terms of powder particle size and morphology evolution and elemental composition. The impact of spark-plasma sintering process on the mechanically alloyed powder is analysed. An optimal set of sintering parameters, including the maximum temperature, the dwell time and the heating rate are determined. (authors)

  3. Crevice corrosion propagation on alloy 625 and alloy C276 in natural seawater

    International Nuclear Information System (INIS)

    McCafferty, E.; Bogar, F.D.; Thomas, E.D. II; Creegan, C.A.; Lucas, K.E.; Kaznoff, A.I.

    1997-01-01

    Chemical composition of the aqueous solution within crevices on two different Ni-Cr-Mo-Fe alloys immersed in natural seawater was determined using a semiquantitative thin-layer chromatographic method. Active crevices were found to contain concentrated amounts of dissolved Ni 2+ , Cr 3+ , Mo 3+ , and Fe 2+ ions. Propagation of crevice corrosion for the two alloys was determined from anodic polarization curves in model crevice solutions based upon stoichiometric dissolution or selective dissolution of alloy components. Both alloys 625 (UNS N06625) and C276 (UNS N10276) underwent crevice corrosion in the model crevice electrolytes. For the model crevice solution based upon selective dissolution of alloy constituents, the anodic dissolution rate for alloy 625 was higher than that for alloy C276. This trend was reversed for the model crevice solution based upon uniform dissolution of alloy constituents

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

    DEFF Research Database (Denmark)

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

    2008-01-01

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

  5. Swelling in neutron-irradiated titanium alloys

    International Nuclear Information System (INIS)

    Peterson, D.T.

    1982-04-01

    Immersion density measurements have been performed on a series of titanium alloys irradiated in EBR-II to a fluence of 5 x 10 22 n/cm 2 (E > 0.1 MeV) at 450 and 550 0 C. The materials irradiated were the near-alpha alloys Ti-6242S and Ti-5621S, the alpha-beta alloy Ti-64, and the beta alloy Ti-38644. Swelling was observed in all alloys with the greater swelling being observed at 550 0 C. Microstructural examination revealed the presence of voids in all alloys. Ti-38644 was found to be the most radiation resistant. Ti-6242S and Ti-5621S also displayed good radiation resistance, whereas considerable swelling and precipitation were observed in Ti-64 at 550 0 C

  6. A highly ductile magnesium alloy system

    International Nuclear Information System (INIS)

    Gao, W; Liu, H

    2009-01-01

    Magnesium (Mg) alloys are finding increasing applications in industry mainly due to their high strength-to-weight ratio. However, they have intrinsically poor plastic deformation ability at room temperature. Therefore, the vast majority of Mg alloys are used only in cast state, severely limiting the development of their applications. We have recently discovered a new Mg alloy system that possesses exceptionally high ductility as well as good mechanical strength. The superior plasticity allows this alloy system to be mechanically deformed at room temperature, directly from an as-cast alloy plate, sheet or ingot into working parts. This type of cold mechanical forming properties has never been reported with any other Mg alloy systems.

  7. Alloy Effects on the Gas Nitriding Process

    Science.gov (United States)

    Yang, M.; Sisson, R. D.

    2014-12-01

    Alloy elements, such as Al, Cr, V, and Mo, have been used to improve the nitriding performance of steels. In the present work, plain carbon steel AISI 1045 and alloy steel AISI 4140 were selected to compare the nitriding effects of the alloying elements in AISI 4140. Fundamental analysis is carried out by using the "Lehrer-like" diagrams (alloy specific Lehrer diagram and nitriding potential versus nitrogen concentration diagram) and the compound layer growth model to simulate the gas nitriding process. With this method, the fundamental understanding for the alloy effect based on the thermodynamics and kinetics becomes possible. This new method paves the way for the development of new alloy for nitriding.

  8. Corrosion resistance of titanium alloys for dentistry

    International Nuclear Information System (INIS)

    Laskawiec, J.; Michalik, R.

    2001-01-01

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

  9. Anodic oxidation of Ta/Fe alloys

    International Nuclear Information System (INIS)

    Mato, S.; Alcala, G.; Thompson, G.E.; Skeldon, P.; Shimizu, K.; Habazaki, H.; Quance, T.; Graham, M.J.; Masheder, D.

    2003-01-01

    The behaviour of iron during anodizing of sputter-deposited Ta/Fe alloys in ammonium pentaborate electrolyte has been examined by transmission electron microscopy, Rutherford backscattering spectroscopy, glow discharge optical emission spectroscopy and X-ray photoelectron spectroscopy. Anodic films on Ta/1.5 at.% Fe, Ta/3 at.% Fe and Ta/7 at.% Fe alloys are amorphous and featureless and develop at high current efficiency with respective formation ratios of 1.67, 1.60 and 1.55 nm V -1 . Anodic oxidation of the alloys proceeds without significant enrichment of iron in the alloy in the vicinity of the alloy/film interface and without oxygen generation during film growth, unlike the behaviour of Al/Fe alloys containing similar concentrations of iron. The higher migration rate of iron species relative to that of tantalum ions leads to the formation of an outer iron-rich layer at the film surface

  10. Nickel aluminide alloy suitable for structural applications

    Science.gov (United States)

    Liu, C.T.

    1998-03-10

    Alloys are disclosed for use in structural applications based upon NiAl to which are added selected elements to enhance room temperature ductility and high temperature strength. Specifically, small additions of molybdenum produce a beneficial alloy, while further additions of boron, carbon, iron, niobium, tantalum, zirconium and hafnium further improve performance of alloys at both room temperature and high temperatures. A preferred alloy system composition is Ni--(49.1{+-}0.8%)Al--(1.0{+-}0.8%)Mo--(0.7 + 0.5%)Nb/Ta/Zr/Hf--(nearly zero to 0.03%)B/C, where the % is at. % in each of the concentrations. All alloys demonstrated good oxidation resistance at the elevated temperatures. The alloys can be fabricated into components using conventional techniques. 4 figs.

  11. Annealing behavior of high permeability amorphous alloys

    International Nuclear Information System (INIS)

    Rabenberg, L.

    1980-06-01

    Effects of low temperature annealing on the magnetic properties of the amorphous alloy Co 71 4 Fe 4 6 Si 9 6 B 14 4 were investigated. Annealing this alloy below 400 0 C results in magnetic hardening; annealing above 400 0 C but below the crystallization temperature results in magnetic softening. Above the crystallization temperature the alloy hardens drastically and irreversibly. Conventional and high resolution transmission electron microscopy were used to show that the magnetic property changes at low temperatures occur while the alloy is truly amorphous. By imaging the magnetic microstructures, Lorentz electron microscopy has been able to detect the presence of microscopic inhomogeneities in this alloy. The low temperature annealing behavior of this alloy has been explained in terms of atomic pair ordering in the presence of the internal molecular field. Lorentz electron microscopy has been used to confirm this explanation

  12. Ti2Al(C, N) Solid Solution Reinforcing TiAl-Based Composites: Evolution of a Core-Shell Structure, Interfaces, and Mechanical Properties.

    Science.gov (United States)

    Song, Xiaojie; Cui, Hongzhi; Han, Ye; Ding, Lei; Song, Qiang

    2018-05-16

    In this work, Ti 2 Al(C, N) solid solution with lamellar structure-enhanced TiAl matrix composites was synthesized by vacuum arc melting, using bulk g-C 3 N 4 , Ti, and Al powders as raw materials. The phases, microstructures, interfaces, and mechanical properties were investigated. MAX phase of Ti 2 Al(C, N) solid solution with lamellar structure was formed. During the melting process, first, C 3 N 4 reacted with Ti to form Ti(C, N) by Ti + C 3 N 4 → Ti(C, N). Then Ti 2 Al(C, N) was formed by a peritectic reaction of TiAl(l) + Ti(C, N)(s) → Ti 2 Al(C, N). C 3 N 4 is the single reactant that provides C and N simultaneously to final product of Ti 2 Al(C, N). The interfaces of TiAl//Ti 2 Al(C, N) and Ti 2 Al(C, N)//Ti(C, N) display perfect orientation relationships with low misfit values. The microhardness, compressive strength, and strain of best-performing TiAl-10 mol % Ti 2 Al(C, N) composite were improved by 45%, 55.7%, and 50% compared with the TiAl alloy, respectively. Uniformly distributed Ti 2 Al(C, N) and unreacted Ti(C, N) particles contributed to the grain refinement and reinforcement of the TiAl matrix. Laminated tearing, particle pull-out, and the crack-arresting of Ti 2 Al(C, N) are crucial for the improvement in compressive strength and plasticity of the composites.

  13. Phase transformations during sintering of mechanically alloyed TiPt

    CSIR Research Space (South Africa)

    Nxumalo, S

    2010-10-01

    Full Text Available Page 307 SMA alloys have been successfully used in several applications including medical, automotive and aerospace as stents, couplings and actuators. The most successful shape memory alloys currently are the NiTi alloys. These are however...

  14. Digital Alloy Absorber for Photodetectors

    Science.gov (United States)

    Hill, Cory J. (Inventor); Ting, David Z. (Inventor); Gunapala, Sarath D. (Inventor)

    2016-01-01

    In order to increase the spectral response range and improve the mobility of the photo-generated carriers (e.g. in an nBn photodetector), a digital alloy absorber may be employed by embedding one (or fraction thereof) to several monolayers of a semiconductor material (insert layers) periodically into a different host semiconductor material of the absorber layer. The semiconductor material of the insert layer and the host semiconductor materials may have lattice constants that are substantially mismatched. For example, this may performed by periodically embedding monolayers of InSb into an InAsSb host as the absorption region to extend the cutoff wavelength of InAsSb photodetectors, such as InAsSb based nBn devices. The described technique allows for simultaneous control of alloy composition and net strain, which are both key parameters for the photodetector operation.

  15. Phonons in fcc binary alloys

    International Nuclear Information System (INIS)

    Sharma, Amita; Rathore, R.P.S.

    1992-01-01

    Born-Mayer potential has been modified to account for the unpaired (three body) forces among the common nearest neighbours of the ordered binary fcc alloys i.e. Ni 3 Fe 7 , Ni 5 Fe 5 and Ni 75 Fe 25 . The three body potential is added to the two body form of Morse to formalize the total interaction potential. Measured inverse ionic compressibility, cohesive energy, lattice constant and one measured phonon frequency are used to evaluate the defining parameters of the potential. The potential seeks to bring about the binding among 140 and 132 atoms though pair wise (two body) and non-pair wise (three body) forces respectively. The phonon-dispersion relations obtained by solving the secular equation are compared with the experimental findings on the aforesaid alloys. (author). 19 refs., 3 figs

  16. Sulfidation/oxidation resistant alloys

    International Nuclear Information System (INIS)

    Smith, G.D.; Tassen, C.S.

    1989-01-01

    The patent describes a nickel-base, high chromium alloy. It is characterized by excellent resistance to sulfidation and oxidation at elevated temperatures as high as 2000 degrees F. (1093 degrees C.) and higher, a stress-rupture life of about 200 hours or more at a temperature at least as high as 1800 degrees F. (990:0083 degrees C.) and under a stress of 2000 psi, good tensile strength and good ductility both at room and elevated temperature. The alloy consists essentially of about 27 to 35% chromium, about 2.5 to 5% aluminum, about 2.5 to about 6% iron, 0.5 to 2.5% columbium, up to 0.1% carbon, up to 1% each of titanium and zirconium, up to 0.05% cerium, up to 0.05% yttrium, up to 1% silicon, up to 1% manganese, and the balance nickel

  17. Heat storage in alloy transformations

    Science.gov (United States)

    Birchenall, C. E.

    1980-01-01

    Heats of transformation of eutectic alloys were measured for many binary and ternary systems by differential scanning calorimetry and thermal analysis. Only the relatively cheap and plentiful elements Mg, Al, Si, P, Ca, Cu, Zn were considered. A method for measuring volume change during transformation was developed using x-ray absorption in a confined sample. Thermal expansion coefficients of both solid and liquid states of aluminum and of its eutectics with copper and with silicon also were determined. Preliminary evaluation of containment materials lead to the selection of silicon carbide as the initial material for study. Possible applications of alloy PCMs for heat storage in conventional and solar central power stations, small solar receivers and industrial furnace operations are under consideration.

  18. The influence of chromium on structure and mechanical properties of B2 nickel aluminide alloys. Ph.D. Thesis - Florida Univ., 1991 Final Report

    Science.gov (United States)

    Cotton, James Dean

    1992-01-01

    Major obstacles to the use of NiAl-based alloys and composites are low ductility and toughness. These shortcomings result in part from a lack of sufficient slip systems to accommodate plastic deformation of polycrystalline material (von Mises Criterion). It has been reported that minor additions of chromium to polycrystalline NiAl cause the predominant slip system to shift from the usual. If true, then a major step toward increasing ductility in this compound may be realized. The purpose of the present study was to verify this phenomenon, characterize it with respect to chromium level and Ni to Al ratio, and correlate any change in slip system with microstructure and mechanical properties. Compression and tensile specimens were prepared from alloys containing 0 to 5 percent chromium and 45 to 55 percent aluminum. Following about one percent strain, transmission electron microscopy foils were produced and the slip systems determined using the g x b = 0 invisibility criterion. Contrary to previous results, chromium was found to have no effect on the preferred slip system of any of the alloys studied. Possible reasons for the inconsistency of the current results with previous work are considered. Composition-structure-property relationships are discerned for the alloys, and good correlation are demonstrated in terms of conventional strengthening models for metallic systems.

  19. Stochastic simulation of nucleation in binary alloys

    Science.gov (United States)

    L’vov, P. E.; Svetukhin, V. V.

    2018-06-01

    In this study, we simulate nucleation in binary alloys with respect to thermal fluctuations of the alloy composition. The simulation is based on the Cahn–Hilliard–Cook equation. We have considered the influence of some fluctuation parameters (wave vector cutoff and noise amplitude) on the kinetics of nucleation and growth of minority phase precipitates. The obtained results are validated by the example of iron–chromium alloys.

  20. Recent developments in advanced aircraft aluminium alloys

    International Nuclear Information System (INIS)

    Dursun, Tolga; Soutis, Costas

    2014-01-01

    Highlights: • To compete with composites, performance of aluminium alloys should be increased. • Al–Li alloys have higher strength, fracture and fatigue/corrosion resistance. • Improvements of aerospace Al alloys are due to optimised solute content and ratios. • In selecting new materials, there should be no reduction in the level of safety. • The use of hybrid materials could provide additional opportunities for Al alloys. - Abstract: Aluminium alloys have been the primary material for the structural parts of aircraft for more than 80 years because of their well known performance, well established design methods, manufacturing and reliable inspection techniques. Nearly for a decade composites have started to be used more widely in large commercial jet airliners for the fuselage, wing as well as other structural components in place of aluminium alloys due their high specific properties, reduced weight, fatigue performance and corrosion resistance. Although the increased use of composite materials reduced the role of aluminium up to some extent, high strength aluminium alloys remain important in airframe construction. Aluminium is a relatively low cost, light weight metal that can be heat treated and loaded to relatively high level of stresses, and it is one of the most easily produced of the high performance materials, which results in lower manufacturing and maintenance costs. There have been important recent advances in aluminium aircraft alloys that can effectively compete with modern composite materials. This study covers latest developments in enhanced mechanical properties of aluminium alloys, and high performance joining techniques. The mechanical properties on newly developed 2000, 7000 series aluminium alloys and new generation Al–Li alloys are compared with the traditional aluminium alloys. The advantages and disadvantages of the joining methods, laser beam welding and friction stir welding, are also discussed

  1. Characterization of aluminium alloys rapidly solidified

    International Nuclear Information System (INIS)

    Monteiro, W.A.

    1988-01-01

    This paper discussed the investigation of the microstructural and mechanical properties of the aluminium alloys (3003; 7050; Al-9% Mg) rapidly solidified by melt spinning process (cooling rate 10 4 - 10 6 K/s). The rapidly solidification process of the studied aluminium alloys brought a microcrystallinity, a minimum presence of coarse precipitation and, also, better mechanical properties of them comparing to the same alloys using ingot process. (author) [pt

  2. Fuel powder production from ductile uranium alloys

    International Nuclear Information System (INIS)

    Clark, C.R.; Meyer, M.K.

    1998-01-01

    Metallic uranium alloys are candidate materials for use as the fuel phase in very-high-density LEU dispersion fuels. These ductile alloys cannot be converted to powder form by the processes routinely used for oxides or intermetallics. Three methods of powder production from uranium alloys have been investigated within the US-RERTR program. These processes are grinding, cryogenic milling, and hydride-dehydride. In addition, a gas atomization process was investigated using gold as a surrogate for uranium. (author)

  3. The oxidation and corrosion of ODS alloys

    Science.gov (United States)

    Lowell, Carl E.; Barrett, Charles A.

    1990-01-01

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

  4. Oxidation And Hot Corrosion Of ODS Alloy

    Science.gov (United States)

    Lowell, Carl E.; Barrett, Charles A.

    1993-01-01

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

  5. Advanced powder metallurgy aluminum alloys and composites

    Science.gov (United States)

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

    1982-01-01

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

  6. Alloy nanoparticle synthesis using ionizing radiation

    Science.gov (United States)

    Nenoff, Tina M [Sandia Park, NM; Powers, Dana A [Albuquerque, NM; Zhang, Zhenyuan [Durham, NC

    2011-08-16

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

  7. PREPARATION OF ACTINIDE-ALUMINUM ALLOYS

    Science.gov (United States)

    Moore, R.H.

    1962-09-01

    BS>A process is given for preparing alloys of aluminum with plutonium, uranium, and/or thorium by chlorinating actinide oxide dissolved in molten alkali metal chloride with hydrochloric acid, chlorine, and/or phosgene, adding aluminum metal, and passing air and/or water vapor through the mass. Actinide metal is formed and alloyed with the aluminum. After cooling to solidification, the alloy is separated from the salt. (AEC)

  8. Microstructural characterization of EXCEL alloy

    International Nuclear Information System (INIS)

    Oroza Z E, Celiz; Saumell M, Lani; Versaci, R A; Bozzano, P B

    2012-01-01

    The microstructure of Excel alloy was studied by optical and scanning electron microscopy. X-ray diffraction was used to analyze the present phases. Characteristic peaks of α-Zr (HCP), β-Zr (BCC) and δhydride (FCC) were identified. The high relatives intensities of certain peaks suggest that samples are textured. Basal poles were dominant in radial-longitudinal planes and prismatic poles have the highest concentration in radial-tangential planes (author)

  9. Chitosan patterning on titanium alloys

    OpenAIRE

    Gilabert Chirivella, Eduardo; Pérez Feito, Ricardo; Ribeiro, Clarisse; Ribeiro, Sylvie; Correia, Daniela; González Martin, María Luisa; Manero Planella, José María; Lanceros Méndez, Senentxu; Gallego Ferrer, Gloria; Gómez Ribelles, José Luis

    2017-01-01

    Titanium and its alloys are widely used in medical implants because of their excellent properties. However, bacterial infection is a frequent cause of titanium-based implant failure and also compromises its osseointegration. In this study, we report a new simple method of providing titanium surfaces with antibacterial properties by alternating antibacterial chitosan domains with titanium domains in the micrometric scale. Surface microgrooves were etched on pure titanium disks at i...

  10. Spray rolling aluminum alloy strip

    Energy Technology Data Exchange (ETDEWEB)

    McHugh, Kevin M.; Delplanque, J.-P.; Johnson, S.B.; Lavernia, E.J.; Zhou, Y.; Lin, Y

    2004-10-10

    Spray rolling combines spray forming with twin-roll casting to process metal flat products. It consists of atomizing molten metal with a high velocity inert gas, cooling the resultant droplets in flight and directing the spray between mill rolls. In-flight convection heat transfer from atomized droplets teams with conductive cooling at the rolls to rapidly remove the alloy's latent heat. Hot deformation of the semi-solid material in the rolls results in fully consolidated, rapidly solidified product. While similar in some ways to twin-roll casting, spray rolling has the advantage of being able to process alloys with broad freezing ranges at high production rates. This paper describes the process and summarizes microstructure and tensile properties of spray-rolled 2124 and 7050 aluminum alloy strips. A Lagrangian/Eulerian poly-dispersed spray flight and deposition model is described that provides some insight into the development of the spray rolling process. This spray model follows droplets during flight toward the rolls, through impact and spreading, and includes oxide film formation and breakup when relevant.

  11. Electrodeposition of engineering alloy coatings

    DEFF Research Database (Denmark)

    Christoffersen, Lasse

    Nickel based electrodeposited alloys were investigated with respect to their deposition process, heat treatment, hardness, corrosion resistance and combined wear-corrosion resistance. The investigated alloys were Ni-B, Ni-P and Ni-W, which are not fully developed for industrial utilisation...... are written in brackets). Temperature and especially pH influenced the cathodic efficiency of the electrodeposition processes for Ni-W and Ni-P. Mass balance problems of the development alloy processes are identified.Heat treatment for one hour at approx. 350°C, 400°C and 600°C of electrodeposited Ni-B, Ni......-P and Ni-W, respectively, resulted in hardness values of approx. 1000 HV0.1 in the case of Ni-P(6), approx. 1100 HV0.1 in the case of Ni-W(40-53) and approx. 1300 HV0.1 in the case of Ni-B(5). Cracks, which emerged during electrodeposition and heat treatment, were observed on Ni-W and Ni-B.The corrosion...

  12. Nanodispersed boriding of titanium alloy

    International Nuclear Information System (INIS)

    Kostyuk, K.O.; Kostyuk, V.O.

    2015-01-01

    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 chemical-thermal treatment. 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. 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 T 2 B, TiB, TiB 2 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). 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

  13. Liquid metal corrosion considerations in alloy development

    International Nuclear Information System (INIS)

    Tortorelli, P.F.; DeVan, J.H.

    1984-01-01

    Liquid metal corrosion can be an important consideration in developing alloys for fusion and fast breeder reactors and other applications. Because of the many different forms of liquid metal corrosion (dissolution, alloying, carbon transfer, etc.), alloy optimization based on corrosion resistance depends on a number of factors such as the application temperatures, the particular liquid metal, and the level and nature of impurities in the liquid and solid metals. The present paper reviews the various forms of corrosion by lithium, lead, and sodium and indicates how such corrosion reactions can influence the alloy development process

  14. Use of low fusing alloy in dentistry.

    Science.gov (United States)

    Wee, A G; Schneider, R L; Aquilino, S A

    1998-11-01

    Low fusing alloy has been used in dentistry for remount procedures in both fixed and removable prosthodontics, in implant prosthodontics for the fabrication of solid implant casts, in maxillofacial prosthetics as oral radiation shields, and in dental research for its unique properties. Previously, the use of low fusing alloy was thought to offer a high degree of dimensional accuracy. However, multiple in vitro studies have shown that its presumed dimensional accuracy may be questionable. This article reviews the physical properties, metallurgical considerations of low fusing alloy, its applications in dentistry, and a safe, simple method of using low fusing alloy.

  15. Synthesis of shape memory alloys using electrodeposition

    Science.gov (United States)

    Hymer, Timothy Roy

    Shape memory alloys are used in a variety of applications. The area of micro-electro-mechanical systems (MEMS) is a developing field for thin film shape memory alloys for making actuators, valves and pumps. Until recently thin film shape memory alloys could only be made by rapid solidification or sputtering techniques which have the disadvantage of being "line of sight". At the University of Missouri-Rolla, electrolytic techniques have been developed that allow the production of shape memory alloys in thin film form. The advantages of this techniques are in-situ, non "line of sight" and the ability to make differing properties of the shape memory alloys from one bath. This research focused on the electrodeposition of In-Cd shape memory alloys. The primary objective was to characterize the electrodeposited shape memory effect for an electrodeposited shape memory alloy. The effect of various operating parameters such as peak current density, temperature, pulsing, substrate and agitation were investigated and discussed. The electrodeposited alloys were characterized by relative shape memory effect, phase transformation, morphology and phases present. Further tests were performed to optimize the shape memory by the use of a statistically designed experiment. An optimized shape memory effect for an In-Cd alloy is reported for the conditions of the experiments.

  16. Characterization of a NIMONIC TYPE super alloy

    International Nuclear Information System (INIS)

    Zamora Rangel, L.; Martinez Martinez, E.

    1985-01-01

    Mechanical properties of strength and thermofluence of a NIMONIC type super alloy under thermal treatment was determined. The relationship between microstructure, phases and precipitates was also studied. (author)

  17. Precipitation and Hardening in Magnesium Alloys

    Science.gov (United States)

    Nie, Jian-Feng

    2012-11-01

    Magnesium alloys have received an increasing interest in the past 12 years for potential applications in the automotive, aircraft, aerospace, and electronic industries. Many of these alloys are strong because of solid-state precipitates that are produced by an age-hardening process. Although some strength improvements of existing magnesium alloys have been made and some novel alloys with improved strength have been developed, the strength level that has been achieved so far is still substantially lower than that obtained in counterpart aluminum alloys. Further improvements in the alloy strength require a better understanding of the structure, morphology, orientation of precipitates, effects of precipitate morphology, and orientation on the strengthening and microstructural factors that are important in controlling the nucleation and growth of these precipitates. In this review, precipitation in most precipitation-hardenable magnesium alloys is reviewed, and its relationship with strengthening is examined. It is demonstrated that the precipitation phenomena in these alloys, especially in the very early stage of the precipitation process, are still far from being well understood, and many fundamental issues remain unsolved even after some extensive and concerted efforts made in the past 12 years. The challenges associated with precipitation hardening and age hardening are identified and discussed, and guidelines are outlined for the rational design and development of higher strength, and ultimately ultrahigh strength, magnesium alloys via precipitation hardening.

  18. Tribological characterization of Al7075–graphite composites fabricated by mechanical alloying and hot extrusion

    International Nuclear Information System (INIS)

    Deaquino-Lara, R.; Soltani, N.; Bahrami, A.; Gutiérrez-Castañeda, E.; García-Sánchez, E.; Hernandez-Rodríguez, M.A.L.

    2015-01-01

    Highlights: • Al7075–graphite composites were synthesized by mechanical alloying and hot extrusion. • Effects of graphite content and milling time on the mechanical and wear properties of fabricated composites were analyzed. • Microstructure and worn surfaces of samples were studied by transmission and scanning electron microscope. • The friction coefficient, wear rate and debris thickness of fabricated composite were investigated. - Abstract: Aluminum matrix composites (AMCs) are candidate materials for aerospace and automotive industry owing to their large elastic modulus, improved strength and low wear rate. A simple method for fabrication of Al7075–graphite composites produced by mechanical alloying (MI) and hot extrusion is described in this paper. Effects of milling time (0–10 h) and graphite concentration (0–1.5 wt.%) on friction, hardness and wear resistance of the AMC were investigated. Wear resistance was determined by the pin-on-disk wear method using 20 and 40 N normal loads at a 0.367 m/s sliding velocity. The worn surfaces were examined by scanning electron microscopy (SEM) to identify distinct topographical features for elucidation of the prevailing wear mechanisms. Experimental results indicated considerable improvement in AMC hardness and wear resistance by adding 1.5% G (wt.) and 10 h of milling, showing homogenous distribution of the reinforcement particles in the Al-base metal-matrix composite. It was found that abrasion is the dominant wear mechanism in all extruded composites, whilst a combination of adhesion and delamination seems to be the governing mechanism for the 7075 aluminum alloy

  19. Thermal conductivity of Al–Cu–Mg–Si alloys: Experimental measurement and CALPHAD modeling

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Cong [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Sino-German cooperation group “Microstructure in Al alloys”, Central South University, Changsha, Hunan 410083 (China); Du, Yong, E-mail: yong-du@csu.edu.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Sino-German cooperation group “Microstructure in Al alloys”, Central South University, Changsha, Hunan 410083 (China); Liu, Shuhong; Liu, Yuling [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Sino-German cooperation group “Microstructure in Al alloys”, Central South University, Changsha, Hunan 410083 (China); Sundman, Bo. [INSTN, CEA Saclay, 91191 Gif-sur-Yvette Cedex (France)

    2016-07-10

    Highlights: • The thermal conductivities of Al–x wt% Cu (x = 1, 3, 5, 15 and 30) and Al–y wt% Si (y = 2, 12.5 and 20) alloys were determined. • The reported thermal conductivities of Al–Cu–Mg–Si system were critically reviewed. • The CALPHAD approach was applied for the modeling of thermal conductivity. • The applicability of CALPHAD technique in the modeling of thermal conductivity was discussed. - Abstract: In the present work, the thermal conductivities and microstructure of Al–x wt% Cu (x = 1, 3, 5, 15 and 30) and Al–y wt% Si (y = 2, 12.5 and 20) alloys were investigated by using laser-flash method, scanning electron microscopy (SEM) and X-ray diffraction (XRD). Besides, a CALPHAD (CALculation of PHAse Diagram) approach to evaluate the thermal conductivity of Al–Cu–Mg–Si system was performed. The numerical models for the thermal conductivity of pure elements and stoichiometric phases were described as polynomials, and the coefficients were optimized via PARROT module of Thermal-Calc software applied to the experimental data. The thermal conductivity of (Al)-based solid solutions was described by using Redlich–Kister interaction parameters. For alloys in two-phase region, the interface scattering parameter was proposed in the modeling to describe the impediment of interfaces on the heat transfer. Finally, a set of self-consistent parameters for the description of thermal conductivity in Al–Cu–Mg–Si system was obtained, and comprehensive comparisons between the calculated and measured thermal conductivities show that the experimental information is satisfactorily accounted for by the present modeling.

  20. Surface treatment of new type aluminum lithium alloy and fatigue crack behaviors of this alloy plate bonded with Ti–6Al–4V alloy strap

    International Nuclear Information System (INIS)

    Sun, Zhen-Qi; Huang, Ming-Hui; Hu, Guo-Huai

    2012-01-01

    Highlights: ► A new generation aluminum lithium alloy which special made for Chinese commercial plane was investigated. ► Pattern of aluminum lithium alloy and Ti alloy were shown after anodization. ► Crack propagation of samples bonded with different wide Ti straps were studied in this paper. -- Abstract: Samples consisting of new aluminum lithium alloy (Al–Li alloy) plate developed by the Aluminum Company of America and Ti–6Al–4V alloy (Ti alloy) plate were investigated. Plate of 400 mm × 140 mm × 2 mm with single edge notch was anodized in phosphoric solution and Ti alloy plate of 200 mm × 20 (40) mm × 2 mm was anodized in alkali solution. Patterns of two alloys were studied at original/anodized condition. And then, aluminum alloy and Ti alloy plates were assembled into a sample with FM 94 film adhesive. Fatigue crack behaviors of the sample were investigated under condition of nominal stress σ = 36 MPa and 54 MPa, stress ratio of 0.1. Testing results show that anodization treatment modifies alloys surface topography. Ti alloy bonding to Al–Li alloy plate effectively retards crack growth than that of Al–Li alloy plate. Fatigue life of sample bonded with Ti alloy strap improves about 62.5% than that of non-strap plate.

  1. Fracture characteristics of uranium alloys by scanning electron microscopy

    International Nuclear Information System (INIS)

    Koger, J.W.; Bennett, R.K. Jr.

    1976-10-01

    The fracture characteristics of uranium alloys were determined by scanning electron microscopy. The fracture mode of stress-corrosion cracking (SCC) of uranium-7.5 weight percent niobium-2.5 weight percent zirconium (Mulberry) alloy, uranium--niobium alloys, and uranium--molybdenum alloys in aqueous chloride solutions is intergranular. The SCC fracture surface of the Mulberry alloy is characterized by very clean and smooth grain facets. The tensile-overload fracture surfaces of these alloys are characteristically ductile dimple. Hydrogen-embrittlement failures of the uranium alloys are brittle and the fracture mode is transgranular. Fracture surfaces of the uranium-0.75 weight percent titanium alloys are quasi cleavage

  2. XRMON-GF: A novel facility for solidification of metallic alloys with in situ and time-resolved X-ray radiographic characterization in microgravity conditions

    Science.gov (United States)

    Nguyen-Thi, H.; Reinhart, G.; Salloum Abou Jaoude, G.; Mathiesen, R. H.; Zimmermann, G.; Houltz, Y.; Voss, D.; Verga, A.; Browne, D. J.; Murphy, A. G.

    2013-07-01

    As most of the phenomena involved during the growth of metallic alloys from the melt are dynamic, in situ and time-resolved X-ray imaging should be retained as the method of choice for investigating the solidification front evolution. On Earth, the gravity force is the major source of various disturbing effects (natural convection, buoyancy/sedimentation, and hydrostatic pressure) which can significantly modify or mask certain physical mechanisms. Therefore solidification under microgravity is an efficient way to eliminate such perturbations to provide unique benchmark data for the validation of models and numerical simulations. Up to now, in situ observation during microgravity solidification experiments were limited to the investigations on transparent organic alloys, using optical methods. On the other hand, in situ observation on metallic alloys generally required synchrotron facilities. This paper reports on a novel facility we have designed and developed to investigate directional solidification on metallic alloys in microgravity conditions with in situ X-ray radiography observation. The facility consists of a Bridgman furnace and an X-ray radiography device specifically devoted to the study of Al-based alloys. An unprecedented experiment was recently performed on board a sounding rocket, with a 6 min period of microgravity. Radiographs were successfully recorded during the entire experiment including the melting and solidification phases of the sample, with a Field-of-View of about 5 mm×5 mm, a spatial resolution of about 4 µm and a frequency of 2 frames per second. Some preliminary results are presented on the solidification of the Al-20 wt% Cu sample, which validate the apparatus and confirm the potential of in situ X-ray characterization for the investigation of dynamical phenomena in materials processing, and particularly for the studying of metallic alloys solidification.

  3. Irradiation-assisted stress corrosion cracking in HTH Alloy X-750 and Alloy 625

    International Nuclear Information System (INIS)

    Bajaj, R.; Mills, W.J.; Lebo, M.R.; Hyatt, B.Z.; Burke, M.G.

    1995-01-01

    In-reactor testing of bolt-loaded compact tension specimens was performed in 360 C water to determine the irradiation-assisted stress corrosion cracking (IASCC) behavior of HTH Alloy X-750 and direct-aged Alloy 625. New data confirm previous results showing that high irradiation levels reduce SCC resistance in Alloy X-750. Heat-to-heat variability correlates with boron content, with low boron heats showing improved IASCC properties. Alloy 625 is resistant to IASCC, as no cracking was observed in any Alloy 625 specimens. Microstructural, microchemical and deformation studies were performed to characterize the mechanisms responsible for IASCC in Alloy X-750 and the lack of an effect in Alloy 625. The mechanisms under investigation are: boron transmutation effects, radiation-induced changes in microstructure and deformation characteristics, and radiation-induced segregation. Irradiation of Alloy X-750 caused significant strengthening and ductility loss that was associated with the formation of cavities and dislocation loops. High irradiation levels did not cause significant segregation of alloying or trace elements in Alloy X-750. Irradiation of Alloy 625 resulted in the formation of small dislocation loops and a fine body-centered-orthorhombic phase. The strengthening due to the loops and precipitates was apparently offset by a partial dissolution of γ double-prime precipitates, as Alloy 625 showed no irradiation-induced strengthening or ductility loss. In the nonirradiated condition, an IASCC susceptible HTH heat containing 28 ppm B showed grain boundary segregation of boron, whereas a nonsusceptible HTH heat containing 2 ppm B and Alloy 625 with 20 ppm B did not show significant boron segregation. Transmutation of boron to helium at grain boundaries, coupled with matrix strengthening, is believed to be responsible for IASCC in Alloy X-750, and the absence of these two effects results in the superior IASCC resistance displayed by Alloy 625

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

    Directory of Open Access Journals (Sweden)

    Kwak Z.

    2015-06-01

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

  5. Synthesis of Amorphous Powders of Ni-Si and Co-Si Alloys by Mechanical Alloying

    Science.gov (United States)

    Omuro, Keisuke; Miura, Harumatsu

    1991-05-01

    Amorphous powders of the Ni-Si and Co-Si alloys are synthesized by mechanical alloying (MA) from crystalline elemental powders using a high energy ball mill. The alloying and amorphization process is examined by X-ray diffraction, differential scanning calorimetry (DSC), and scanning electron microscopy. For the Ni-Si alloy, it is confirmed that the crystallization temperature of the MA powder, measured by DSC, is in good agreement with that of the powder sample prepared by mechanical grinding from the cast alloy ingot products of the same composition.

  6. Phase-field simulations of α → γ precipitations and transition to massive transformation in the Ti-Al alloy

    International Nuclear Information System (INIS)

    Singer, H.M.; Singer, I.; Jacot, A.

    2009-01-01

    A phase-field model for the solid-solid α → γ transition of Ti-Al binary alloys is presented based on analytical Gibbs free energies and couplings to the thermodynamical database ThermoCalc. The equilibrium values recover the α + γ phase boundaries. Morphological transitions from diffusive to massive (partitionless) growth are observed on increasing the initial mole fraction of aluminum. Temporal evolution of the interface shows a √(t) behavior for diffusive and a linear behavior for massive growth, which is in accordance with theoretical predictions. An estimate of the interfacial mobility of Ti-Al based on the Burke-Turnbull equation is calculated. The expression of the mobility follows an Arrhenius law. Using the derived interfacial mobility, the calculated interfacial velocities of the massive transformation are in quantitative agreement with those observed in experiments

  7. The Evaluation of the Corrosion Resistance of the Al-Si Alloys Antimony Alloyed

    Directory of Open Access Journals (Sweden)

    Svobodova J.

    2014-06-01

    Full Text Available This paper deals with the evaluation of the corrosion resistance of the Al-Si alloys alloyed with the different amount of antimony. Specifically it goes about the alloy AlSi7Mg0,3 which is antimony alloyed in the concentrations 0; 0,001; 0,005; 0,01 a 0,05 wt. % of antimony. The introduction of the paper is dedicated to the theory of the aluminium alloys corrosion resistance, testing and evaluation of the corrosion resistance. The influence of the antimony to the Al-Si alloys properties is described further in the introduction. The experimental part describes the experimental samples which were prepared for the experiment and further they were exposed to the loading in the atmospheric conditions for a period of the 3 months. The experimental samples were evaluated macroscopically and microscopically. The results of the experiment were documented and the conclusions in terms of the antimony impact to the corrosion resistance of the Al-Si alloy were concluded. There was compared the corrosion resistance of the Al-Si alloy antimony alloyed (with the different antimony content with the results of the Al-Si alloy without the alloying after the corrosion load in the atmospheric conditions in the experiment.

  8. Mechanical Properties of Low Density Alloys at Cryogenic Temperatures

    International Nuclear Information System (INIS)

    Jiao, X. D.; Liu, H. J.; Li, L. F.; Yang, K.

    2006-01-01

    Low-density alloys include aluminum alloys, titanium alloys and magnesium alloys. Aluminum alloys and titanium alloys have been widely investigated and used as structural materials for cryogenic applications because of their light weight and good low-temperature mechanical properties.For aerospace applications, persistent efforts are being devoted to reducing weight and improving performance. Magnesium alloys are the lightest structural alloys among those mentioned above. Therefore, it is necessary to pay attention to magnesium alloys and to investigate their behaviors at cryogenic temperatures. In this paper, we have investigated the mechanical properties and microstructures of some magnesium alloys at cryogenic temperatures. Experimental results on both titanium and magnesium alloys are taken into account in considering these materials for space application

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

    Science.gov (United States)

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

    2017-05-01

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

  10. Synthesis Of NiCrAlC alloys by mechanical alloying

    International Nuclear Information System (INIS)

    Silva, A.K.; Pereira, J.I.; Vurobi Junior, S.; Cintho, O.M.

    2010-01-01

    The purpose of the present paper is the synthesis of nickel alloys (NiCrAlC), which has been proposed like a economic alternative to the Stellite family Co alloys using mechanical alloying, followed by sintering heat treatment of milled material. The NiCrAlC alloys consist of a chromium carbides dispersion in a Ni 3 Al intermetallic matrix, that is easily synthesized by mechanical alloying. The use of mechanical alloying enables higher carbides sizes and distribution control in the matrix during sintering. We are also investigated the compaction of the processed materials by compressibility curves. The milling products were characterized by X-ray diffraction, and the end product was featured by conventional metallography and scanning electronic microscopy (SEM), that enabled the identification of desired phases, beyond microhardness test, which has been shown comparable to alloys manufactured by fusion after heat treating. (author)

  11. Combinatorial thin film materials science: From alloy discovery and optimization to alloy design

    Energy Technology Data Exchange (ETDEWEB)

    Gebhardt, Thomas, E-mail: gebhardt@mch.rwth-aachen.de; Music, Denis; Takahashi, Tetsuya; Schneider, Jochen M.

    2012-06-30

    This paper provides an overview of modern alloy development, from discovery and optimization towards alloy design, based on combinatorial thin film materials science. The combinatorial approach, combining combinatorial materials synthesis of thin film composition-spreads with high-throughput property characterization has proven to be a powerful tool to delineate composition-structure-property relationships, and hence to efficiently identify composition windows with enhanced properties. Furthermore, and most importantly for alloy design, theoretical models and hypotheses can be critically appraised. Examples for alloy discovery, optimization, and alloy design of functional as well as structural materials are presented. Using Fe-Mn based alloys as an example, we show that the combination of modern electronic-structure calculations with the highly efficient combinatorial thin film composition-spread method constitutes an effective tool for knowledge-based alloy design.

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

    Science.gov (United States)

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

    2016-05-03

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

  13. Combinatorial thin film materials science: From alloy discovery and optimization to alloy design

    International Nuclear Information System (INIS)

    Gebhardt, Thomas; Music, Denis; Takahashi, Tetsuya; Schneider, Jochen M.

    2012-01-01

    This paper provides an overview of modern alloy development, from discovery and optimization towards alloy design, based on combinatorial thin film materials science. The combinatorial approach, combining combinatorial materials synthesis of thin film composition-spreads with high-throughput property characterization has proven to be a powerful tool to delineate composition–structure–property relationships, and hence to efficiently identify composition windows with enhanced properties. Furthermore, and most importantly for alloy design, theoretical models and hypotheses can be critically appraised. Examples for alloy discovery, optimization, and alloy design of functional as well as structural materials are presented. Using Fe-Mn based alloys as an example, we show that the combination of modern electronic-structure calculations with the highly efficient combinatorial thin film composition-spread method constitutes an effective tool for knowledge-based alloy design.

  14. Modification of Sr on 4004 Aluminum Alloy

    Science.gov (United States)

    Guo, Erjun; Cao, Guojian; Feng, Yicheng; Wang, Liping; Wang, Guojun; Lv, Xinyu

    2013-05-01

    As a brazing foil, 4004 Al alloy has good welding performance. However, the high Si content decreases the plasticity of the alloy. To improve the plasticity of 4004 Al alloy and subsequently improve the productivity of 4004 Al foil or 434 composite foil, 4004 Al alloy was modified by Al-10%Sr master alloy. Modification effects of an additional amount of Sr, modification temperature, and holding time on 4004 aluminum alloy were studied by orthogonal design. The results showed that the greatest impact parameter of 4004 aluminum alloy modification was the additional amount of Sr, followed by holding time and modification temperature. The optimum modification parameters obtained by orthogonal design were as follows: Sr addition of 0.04%, holding time of 60 min, and modification temperature of 760°C. The effect of Sr addition on modification was analyzed in detail based on orthogonal results. With increasing of Sr addition, elongation of 4004 alloy increased at first, and decreased after reaching the maximum value.

  15. METHOD AND ALLOY FOR BONDING TO ZIRCONIUM

    Science.gov (United States)

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

    1960-04-19

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

  16. Electrodeposition of zinc--nickel alloys coatings

    Energy Technology Data Exchange (ETDEWEB)

    Dini, J W; Johnson, H R

    1977-10-01

    One possible substitute for cadmium in some applications is a zinc--nickel alloy deposit. Previous work by others showed that electrodeposited zinc--nickel coatings containing about 85 percent zinc and 15 percent nickel provided noticeably better corrosion resistance than pure zinc. Present work which supports this finding also shows that the corrosion resistance of the alloy deposit compares favorably with cadmium.

  17. Development of high performance ODS alloys

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Lin [Texas A & M Univ., College Station, TX (United States); Gao, Fei [Univ. of Michigan, Ann Arbor, MI (United States); Garner, Frank [Texas A & M Univ., College Station, TX (United States)

    2018-01-29

    This project aims to capitalize on insights developed from recent high-dose self-ion irradiation experiments in order to develop and test the next generation of optimized ODS alloys needed to meet the nuclear community's need for high strength, radiation-tolerant cladding and core components, especially with enhanced resistance to void swelling. Two of these insights are that ferrite grains swell earlier than tempered martensite grains, and oxide dispersions currently produced only in ferrite grains require a high level of uniformity and stability to be successful. An additional insight is that ODS particle stability is dependent on as-yet unidentified compositional combinations of dispersoid and alloy matrix, such as dispersoids are stable in MA957 to doses greater than 200 dpa but dissolve in MA956 at doses less than 200 dpa. These findings focus attention on candidate next-generation alloys which address these concerns. Collaboration with two Japanese groups provides this project with two sets of first-round candidate alloys that have already undergone extensive development and testing for unirradiated properties, but have not yet been evaluated for their irradiation performance. The first set of candidate alloys are dual phase (ferrite + martensite) ODS alloys with oxide particles uniformly distributed in both ferrite and martensite phases. The second set of candidate alloys are ODS alloys containing non-standard dispersoid compositions with controllable oxide particle sizes, phases and interfaces.

  18. TERNARY ALLOYS OF URANIUM, COLUMBIUM, AND ZIRCONIUM

    Science.gov (United States)

    Foote, F.G.

    1960-08-01

    Ternary alloys of uranium are described which are useful as neutron- reflecting materials in a fast neutron reactor. They are especially resistant to corrosion caused by oxidative processes of gascous or aqueous origin and comprise uranium as the predominant metal with zirconiunn and niobium wherein the total content of the minor alloying elements is between 2 and 8% by weight.

  19. Bulk amorphous Mg-based alloys

    DEFF Research Database (Denmark)

    Pryds, Nini

    2004-01-01

    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...

  20. Titanium and titanium alloys: fundamentals and applications

    National Research Council Canada - National Science Library

    Leyens, C; Peters, M

    2003-01-01

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

  1. Iron titanium manganase alloy hydrogen storage

    Science.gov (United States)

    Reilly, James J.; Wiswall, Jr., Richard H.

    1979-01-01

    A three component alloy capable of reversible sorption of hydrogen having the chemical formula TiFe.sub.1-x Mn.sub.x where x is in the range of about 0.02 to 0.5 and the method of storing hydrogen using said alloy.

  2. Irradiation of copper alloys in FFTF

    International Nuclear Information System (INIS)

    Brager, H.R.; Garner, F.A.

    1984-01-01

    Nine copper-base alloys in thirteen material conditions have been inserted into the MOTA-18 experiment for irradiation in FFTF at approx.450 0 C. The alloy Ni-1.9Be is also included in this experiment, which includes both TEM disks and miniature tensile specimens

  3. Additive Manufacturing of Metastable Beta Titanium Alloys

    Science.gov (United States)

    Yannetta, Christopher J.

    Additive manufacturing processes of many alloys are known to develop texture during the deposition process due to the rapid reheating and the directionality of the dissipation of heat. Titanium alloys and with respect to this study beta titanium alloys are especially susceptible to these effects. This work examines Ti-20wt%V and Ti-12wt%Mo deposited under normal additive manufacturing process parameters to examine the texture of these beta-stabilized alloys. Both microstructures contained columnar prior beta grains 1-2 mm in length beginning at the substrate with no visible equiaxed grains. This microstructure remained constant in the vanadium system throughout the build. The microstructure of the alloy containing molybdenum changed from a columnar to an equiaxed structure as the build height increased. Eighteen additional samples of the Ti-Mo system were created under different processing parameters to identify what role laser power and travel speed have on the microstructure. There appears to be a correlation in alpha lath size and power density. The two binary alloys were again deposited under the same conditions with the addition of 0.5wt% boron to investigate the effects an insoluble interstitial alloying element would have on the microstructure. The size of the prior beta grains in these two alloys were reduced with the addition of boron by approximately 50 (V) and 100 (Mo) times.

  4. Phase transformations on Zr-Nb alloys

    International Nuclear Information System (INIS)

    Doi, Sergio Norifumi

    1980-01-01

    This research intended the laboratory scale experimental development of Zr-Nb alloys with adequate characteristics for use as fuel element cladding or for the making of irradiation capsules. Zr-Nb alloys with different Nb contents were melted and the resulting material was characterised. The following metallurgical aspects were considered: preparation of Zr-Nb alloys with various Nb contents; heat and thermomechanical treatments; microstructural characterization; mechanical properties; oxidation properties. The influence of the heat treatment and thermomechanical treatment, on the out-of-pile mechanical and oxidation properties of the Zr-Nb alloys were studied. It was found that the alloy microhardness increases with the Nb content and/or with the thermomechanical treatment. Mechanical properties such as yield and ultimate tensile strength as well as elongation were determined by means of compression tests. The results showed that the alloy yield stress increases with the Nb content and with the thermomechanical treatment, while its elongation decreases. Thermogravimetric analysis determined the alloy oxidation kinetics, in the 400 - 800 deg C interval, at 1 atm. oxygen pressure. The results showed that the alloy oxidation rate increases with the temperature and Nb content. It was also observed that the oxidation rate increases considerably for temperatures higher than 600 deg C.(author)

  5. Theory of Rare-Earth Alloys

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker

    1977-01-01

    A mean-field random alloy theory combined with a simple calculation of the exchange interaction J(c,Q) is shown to quantitatively account for the phase diagrams for alloys of rare-earth metals with Y, Lu, Sc, and other rare-earth metals. A concentration-dependent J(c,Q) explains the empirical 2...

  6. Intermetallic alloys: Deformation, mechanical and fracture behaviour

    International Nuclear Information System (INIS)

    Dogan, B.

    1988-01-01

    The state of the art in intermetallic alloys development with particular emphasis on deformation, mechanical and fracture behaviour is documented. This review paper is prepared to lay the ground stones for a future work on mechanical property characterization and fracture behaviour of intermetallic alloys at GKSS. (orig.)

  7. Review of tantalum and niobium alloy production

    International Nuclear Information System (INIS)

    Buckman, R.W. Jr.

    1984-01-01

    This paper concentrates on the current state of niobium- and tantalum-base alloy production. The materials requirements, alloy compositions of interest, and production status are discussed. Finally, a list of developments needed to support the SP-100 program will be identified. A bibliography is included

  8. Electrocatalysis on bimetallic and alloy surfaces

    NARCIS (Netherlands)

    Koper, M.T.M.

    2004-01-01

    Bimetallic surfaces and alloys are well known to have unique catalytic properties for many important chemical transformations [1]. In electrocatalysis, bimetallic and alloy catalysts have been a particularly active area of research in relation to low-temperature fuel cells [2]. On the anode side,

  9. Machining of uranium and uranium alloys

    International Nuclear Information System (INIS)

    Morris, T.O.

    1981-01-01

    Uranium and uranium alloys can be readily machined by conventional methods in the standard machine shop when proper safety and operating techniques are used. Material properties that affect machining processes and recommended machining parameters are discussed. Safety procedures and precautions necessary in machining uranium and uranium alloys are also covered. 30 figures

  10. Alloys of clathrate allotropes for rechargeable batteries

    Science.gov (United States)

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

    2014-12-09

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

  11. Impact toughness of laser surface alloyed Aluminium

    CSIR Research Space (South Africa)

    Mabhali, Luyolo AB

    2012-03-01

    Full Text Available with intermetallic phases and metal matrix composites were achieved during laser alloying. Brittle fracture of the SiC particles and transgranular cracking of the intermetallic phases was observed for the laser alloyed samples, while ductile fracture was observed...

  12. Superconductivity in zirconium-rhodium alloys

    Science.gov (United States)

    Zegler, S. T.

    1969-01-01

    Metallographic studies and transition temperature measurements were made with isothermally annealed and water-quenched zirconium-rhodium alloys. The results clarify both the solid-state phase relations at the Zr-rich end of the Zr-Rh alloy system and the influence upon the superconducting transition temperature of structure and composition.

  13. Grain refinement of zinc-aluminium alloys

    International Nuclear Information System (INIS)

    Zaid, A.I.O.

    2006-01-01

    It is now well-established that the structure of the zinc-aluminum die casting alloys can be modified by the binary Al-Ti or the ternary Al-Ti-B master alloys. in this paper, grain refinement of zinc-aluminum alloys by rare earth materials is reviewed and discussed. The importance of grain refining of these alloys and parameters affecting it are presented and discussed. These include parameters related to the Zn-Al alloys cast, parameters related to the grain refining elements or alloys and parameters related to the process. The effect of addition of other alloying elements e.g. Zr either alone or in the presence of the main grain refiners Ti or Ti + B on the grain refining efficiency is also reviewed and discussed. Furthermore, based on the grain refinement and the parameters affecting it, a criterion for selection of the optimum grain refiner is suggested. Finally, the recent research work on the effect of grain refiners on the mechanical behaviour, impact strength, wear resistance, and fatigue life of these alloys are presented and discussed. (author)

  14. Fundamental irradiation studies on vanadium alloys

    International Nuclear Information System (INIS)

    Loomis, B.A.; Garner, F.A.; Ermi, A.M.

    1985-05-01

    A joint experiment on the irradiation response of simple vanadium alloys has been initiated under the auspices of the DAFS and BES progams. Specimen fabrication is nearly complete and the alloys are expected to be irradiated in lithium in FFTF-MOTA Cycles 7 and 8

  15. Zirconium alloy barrier having improved corrosion resistance

    International Nuclear Information System (INIS)

    Adamson, R.B.; Rosenbaum, H.S.

    1983-01-01

    A nuclear fuel element for use in the core of a nuclear reactor has a composite cladding container having a substrate and a dilute zirconium alloy liner bonded to the inside surface of the substrate. The dilute zirconium alloy liner forms about 1 to about 20 percent of the thickness of the cladding and is comprised of zirconium and a metal selected from the group consisting of iron, chromium, iron plus chromium, and copper. The dilute zirconium alloy liner shields the substrate from impurities or fission products from the nuclear fuel material and protects the substrate from stress corrosion and stress cracking. The dilute zirconium alloy liner displays greater corrosion resistance, especially to oxidation by hot water or steam than unalloyed zirconium. The substrate material is selected from conventional cladding materials, and preferably is a zirconium alloy. (author)

  16. Corrosion resistance improvement of titanium base alloys

    Directory of Open Access Journals (Sweden)

    Mihai V. Popa

    2010-01-01

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

  17. Nature of negative microplastic deformation in alloys

    International Nuclear Information System (INIS)

    Palatnik, L.S.; Ivantsov, V.I.; Kagan, Ya.I.; Papirov, I.I.; Fat'yanova, N.B.; AN Ukrainskoj SSR, Kharkov. Fiziko-Tekhnicheskij Inst.)

    1985-01-01

    The paper deals with investigation of microplastic deformation of corrosion resistant aging 40KhNYU alloy and the study of physical nature of negative microdeformation in this alloy under tension. Investigation of microplasticity of 40KhNYU alloy was conducted by the method of mechanostatic hysteresis using resistance strain gauge for measuring stresses and deformations. Microplasticity curves for 40KhNYU alloy were obtained. They represent the result of competition between usual (positive) microdeformation and phase (negative) deformation under tensile effect on the alloy. It was established that the negative microdeformation increment occurs during secondary aging of the phase precipitated from initial supersat urated solid solution (primary decomposition product). This phase decomposes under tension with disperse phase precipitation which promotes decreasing its specific volume and specimen volume as a whole

  18. Refining processes of selected copper alloys

    Directory of Open Access Journals (Sweden)

    S. Rzadkosz

    2009-04-01

    Full Text Available The analysis of the refining effectiveness of the liquid copper and selected copper alloys by various micro additions and special refiningsubstances – was performed. Examinations of an influence of purifying, modifying and deoxidation operations performed in a metal bath on the properties of certain selected alloys based on copper matrix - were made. Refining substances, protecting-purifying slag, deoxidation and modifying substances containing micro additions of such elements as: zirconium, boron, phosphor, sodium, lithium, or their compounds introduced in order to change micro structures and properties of alloys, were applied in examinations. A special attention was directed to macro and micro structures of alloys, their tensile and elongation strength and hot-cracks sensitivity. Refining effects were estimated by comparing the effectiveness of micro structure changes with property changes of copper and its selected alloys from the group of tin bronzes.

  19. Underwater laser beam welding of Alloy 690

    International Nuclear Information System (INIS)

    Hino, Takehisa; Tamura, Masataka; Kono, Wataru; Kawano, Shohei; Yoda, Masaki

    2009-01-01

    Stress Corrosion Clacking (SCC) has been reported at Alloy 600 welds between nozzles and safe-end in Pressurized Water Reactor (PWR) plant. Alloy 690, which has higher chromium content than Alloy 600, has been applied for cladding on Alloy 600 welds for repairing damaged SCC area. Toshiba has developed Underwater Laser Beam Welding technique. This method can be conducted without draining, so that the repairing period and the radiation exposure during the repair can be dramatically decreased. In some old PWRs, high-sulfur stainless steel is used as the materials for this section. It has a high susceptibility of weld cracks. Therefore, the optimum welding condition of Alloy 690 on the high-sulfur stainless steel was investigated with our Underwater Laser Beam Welding unit. Good cladding layer, without any crack, porosity or lack of fusion, could be obtained. (author)

  20. Machinability of experimental Ti-Ag alloys.

    Science.gov (United States)

    Kikuchi, Masafumi; Takahashi, Masatoshi; Okuno, Osamu

    2008-03-01

    This study investigated the machinability of experimental Ti-Ag alloys (5, 10, 20, and 30 mass% Ag) as a new dental titanium alloy candidate for CAD/CAM use. The alloys were slotted with a vertical milling machine and carbide square end mills under two cutting conditions. Machinability was evaluated through cutting force using a three-component force transducer fixed on the table of the milling machine. The horizontal cutting force of the Ti-Ag alloys tended to decrease as the concentration of silver increased. Values of the component of the horizontal cutting force perpendicular to the feed direction for Ti-20% Ag and Ti-30% Ag were more than 20% lower than those for titanium under both cutting conditions. Alloying with silver significantly improved the machinability of titanium in terms of cutting force under the present cutting conditions.

  1. Internal chlorination of Ni-Cr alloys

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-12-31

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

  2. Beryllium-aluminum alloys for investment castings

    International Nuclear Information System (INIS)

    Nachtrab, W.T.; Levoy, N.

    1997-01-01

    Beryllium-aluminum alloys containing greater than 60 wt % beryllium are very favorable materials for applications requiring light weight and high stiffness. However, when produced by traditional powder metallurgical methods, these alloys are expensive and have limited applications. To reduce the cost of making beryllium-aluminum components, Nuclear Metals Inc. (NMI) and Lockheed Martin Electronics and Missiles have recently developed a family of patented beryllium-aluminum alloys that can be investment cast. Designated Beralcast, the alloys can achieve substantial weight savings because of their high specific strength and stiffness. In some cases, weight has been reduced by up to 50% over aluminum investment casting. Beralcast is now being used to make thin wall precision investment castings for several advanced aerospace applications, such as the RAH-66 Comanche helicopter and F-22 jet fighter. This article discusses alloy compositions, properties, casting method, and the effects of cobalt additions on strength

  3. Enthalpies of a binary alloy during solidification

    Science.gov (United States)

    Poirier, D. R.; Nandapurkar, P.

    1988-01-01

    The purpose of the paper is to present a method of calculating the enthalpy of a dendritic alloy during solidification. The enthalpies of the dendritic solid and interdendritic liquid of alloys of the Pb-Sn system are evaluated, but the method could be applied to other binaries, as well. The enthalpies are consistent with a recent evaluation of the thermodynamics of Pb-Sn alloys and with the redistribution of solute in the same during dendritic solidification. Because of the heat of mixing in Pb-Sn alloys, the interdendritic liquid of hypoeutectic alloys (Pb-rich) of less than 50 wt pct Sn has enthalpies that increase as temperature decreases during solidification.

  4. Magnesium and related low alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, J; Caillat, R; Darras, R [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1959-07-01

    In the first part the authors examine the comparative corrosion of commercial magnesium, of a magnesium-zirconium alloy (0,4 per cent {<=} Zr {<=} 0,7 per cent) of a ternary magnesium-zinc-zirconium alloy (0,8 per cent {<=} Zn {<=} 1,2 per cent) and of english 'Magnox type' alloys, in dry carbon dioxide-free air, in damp carbon dioxide-free air, and in dry and damp carbon dioxide, at temperatures from 300 to 600 deg. C. In the second part the structural stability of these materials is studied after annealings, of 10 to 1000 hours at 300 to 450 deg. C. Variations in grain after these heat treatments and mechanical stretching properties at room temperature are presented. Finally various creep rate and life time diagrams are given for these materials, for temperatures ranging from 300 to 450 deg. C. (author) [French] Dans une premiere partie les auteurs etudient la corrosion comparee du magnesium commercial, d'un alliage magnesium-zirconium (0,4 pour cent {<=} Zr {<=} 0,7 pour cent), d'un alliage ternaire magnesium-zinc-zirconium (0,8 pour cent {<=} Zn {<=} 1,2 pour cent), et d'alliages anglais 'type Magnox', dans l'air sec decarbonate, l'air humide decarbonate, le gaz carbonique sec et humide a des temperatures de 300 a 600 deg. C. Dans une seconde partie, est etudiee la stabilite structurale de ces materiaux apres des recuits de 300 a 450 deg. C, et de 10 a 1000 heures. Sont presentees les variations, apres ces traitements thermiques, de la grosseur du grain, et des caracteristiques mecaniques de traction a la temperature ambiante. Enfin, quelques diagrammes de vitesse de fluage et de durees de vie sont presentes sur ces materiaux pour des temperatures variant entre 300 et 450 deg. C. (auteur)

  5. Plating on stainless steel alloys

    International Nuclear Information System (INIS)

    Dini, J.W.; Johnson, H.R.

    1981-01-01

    Quantitative adhesion data are presented for a variety of electroplated stainless steel type alloys. Results show that excellent adhesion can be obtained by using a Wood's nickel strike or a sulfamate nickel strike prior to final plating. Specimens plated after Wood's nickel striking failed in the deposit rather than at the interface between the substrate and the coating. Flyer plate quantitative tests showed that use of anodic treatment in sulfuric acid prior to Wood's nickel striking even further improved adhesion. In contrast activation of stainless steels by immersion or cathodic treatment in hydrochloric acid resulted in very reduced bond strengths with failure always occurring at the interface between the coating and substrate

  6. Phase diagrams for surface alloys

    DEFF Research Database (Denmark)

    Christensen, Asbjørn; Ruban, Andrei; Stoltze, Per

    1997-01-01

    We discuss surface alloy phases and their stability based on surface phase diagrams constructed from the surface energy as a function of the surface composition. We show that in the simplest cases of pseudomorphic overlayers there are four generic classes of systems, characterized by the sign...... is based on density-functional calculations using the coherent-potential approximation and on effective-medium theory. We give self-consistent density-functional results for the segregation energy and surface mixing energy for all combinations of the transition and noble metals. Finally we discuss...

  7. Corrosion and protection of magnesium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ghali, E. [Laval Univ., Quebec City, PQ (Canada). Dept. of Mining and Metallurgy

    2000-07-01

    The oxide film on magnesium offers considerable surface protection in rural and some industrial environments and the corrosion rate lies between that of aluminum and low carbon steels. Galvanic coupling of magnesium alloys, high impurity content such as Ni, Fe, Cu and surface contamination are detrimental for corrosion resistance of magnesium alloys. Alloying elements can form secondary particles which are noble to the Mg matrix, thereby facilitating corrosion, or enrich the corrosion product thereby possibly inhibiting the corrosion rate. Bimetallic corrosion resistance can be increased by fluxless melt protection, choice of compatible alloys, insulating materials, and new high-purity alloys. Magnesium is relatively insensible to oxygen concentration. Pitting, corrosion in the crevices, filiform corrosion are observed. Granular corrosion of magnesium alloys is possible due to the cathodic grain-boundary constituent. More homogeneous microstructures tend to improve corrosion resistance. Under fatigue loading conditions, microcrack initiation in Mg alloys is related to slip in preferentially oriented grains. Coating that exclude the corrosive environments can provide the primary defense against corrosion fatigue. Magnesium alloys that contain neither aluminum nor zinc are the most SCC resistant. Compressive surface residual stresses as that created by short peening increase SCC resistance. Cathodic polarization or cladding with a SCC resistant sheet alloy are good alternatives. Effective corrosion prevention for magnesium alloy components and assemblies should start at the design stage. Selective surface preparation, chemical treatment and coatings are recommended. Oil application, wax coating, anodizing, electroplating, and painting are possible alternatives. Recently, it is found that a magnesium hydride layer, created on the magnesium surface by cathodic charging in aqueous solution is a good base for painting. (orig.)

  8. Processing and properties of Nb-Ti-based alloys

    International Nuclear Information System (INIS)

    Sikka, V.K.; Viswanathan, S.

    1992-01-01

    The processing characteristics, tensile properties, and oxidation response of two Nb-Ti-Al-Cr alloys were investigated. One creep test at 650 C and 172 MPa was conducted on the base alloy which contained 40Nb-40Ti-10Al-10Cr. A second alloy was modified with 0.11 at. % carbon and 0.07 at. % yttrium. Alloys were arc melted in a chamber backfilled with argon, drop cast into a water-cooled copper mold, and cold rolled to obtain a 0.8-mm sheet. The sheet was annealed at 1,100 C for 0.5 h. Longitudinal tensile specimens and oxidation specimens were obtained for both the base alloy and the modified alloy. Tensile properties were obtained for the base alloy at room temperature, 400, 600, 700, 800, 900, and 1,000 C, and for the modified alloy at room temperature, 400, 600, 700, and 800 C. Oxidation tests on the base alloy and modified alloy, as measured by weight change, were carried out at 600, 700, 800, and 900 C. Both the base alloy and the modified alloy were extremely ductile and were cold rolled to the final sheet thickness of 0.8 mm without an intermediate anneal. The modified alloy exhibited some edge cracking during cold during cold rolling. Both alloys recrystallized at the end of a 0.5-h annealing treatment. The alloys exhibited moderate strength and oxidation resistance below 600 C, similar to the results of alloys reported in the literature

  9. Characterization of zinc–nickel alloy electrodeposits obtained from ...

    Indian Academy of Sciences (India)

    Zinc alloy offers superior sacrificial protection to steel as the alloy dissolves more slowly than pure zinc. The degree of protection and the rate of dissolution depend on the alloying metal and its composition. Zinc-nickel alloy may also serve as at less toxic substitute for cadmium. In this paper the physico-chemical ...

  10. Study of fatigue behaviour of 7475 aluminium alloy

    Indian Academy of Sciences (India)

    Unknown

    controlled toughness alloy developed for applications that require a combination of high strength, superior fracture toughness and resistance to fatigue crack propagation both in air and aggressive environment. The 7475 alu- minium alloy is basically a modified version of 7075 alloy. Properties in 7075 alloy are improved by ...

  11. Characteristics of Film Formed on Alloy 600 and Alloy 690 in Water Containing lead

    International Nuclear Information System (INIS)

    Hwang Seong Sik; Lee, Deok Hyun; Kim, Hong Pyo; Kim, Joung Soo; Kim, Ju Yup

    1999-01-01

    Anodic polarization behaviors of Alloy 600 and Alloy 690 have been studied as a function of lead content in the solution of pH 4 and 10 at 90 .deg. C. As the amount of lead in the solution increased, critical current densities and passive current densities of Alloy 600 and Alloy 690 increased, while the breakdown potential of the alloys decreased. The high critical current density in the high lead solution was thought to come from the combination of an enhanced dissolution of constituents on the surface of the alloys by the lead and an anodic dissolution of metallic lead deposited on the surface of the specimens. The morphology of lead precipitated on the specimen after the anodic scan changed with the pH of solution: small irregular particles were precipitated on the surface of the specimen in the solution of pH 4, while the high density of regular sized particles was formed on it in the solution of pH 10.Pb was observed to enhance Cr depletion from the outer surface of Alloy 600 and Alloy 690 and also to increase the ratio of O 2- /OH - in the surface film formed in the high lead solution. The SCC resistance of Alloy 600 and Alloy 690 may have decreased due to the poor quality of the passive film formed and the enhanced oxygen evolution in the solution containing lead

  12. A sulfidation-resistant nickel-base alloy

    International Nuclear Information System (INIS)

    Lai, G.Y.

    1989-01-01

    For applications in mildly to moderately sulfidizing environments, stainless steels, Fe-Ni-Cr alloys (e.g., alloys 800 and 330), and more recently Fe-Ni-Cr-Co alloys (e.g., alloy 556) are frequently used for construction of process equipment. However, for many highly sulfidizing environments, few existing commercial alloys have adequate performance. Thus, a new nickel-based alloy containing 27 wt.% Co, 28 wt.% Cr, 4 wt.% Fe, 2.75 wt.% Si, 0.5 wt.% Mn and 0.05 wt.% C (Haynes alloy HR-160) was developed

  13. A review on magnesium alloys as biodegradable materials

    Science.gov (United States)

    Gu, Xue-Nan; Zheng, Yu-Feng

    2010-06-01

    Magnesium alloys attracted great attention as a new kind of degradable biomaterials. One research direction of biomedical magnesium alloys is based on the industrial magnesium alloys system, and another is the self-designed biomedical magnesium alloys from the viewpoint of biomaterials. The mechanical, biocorrosion properties and biocompatibilities of currently reported Mg alloys were summarized in the present paper, with the mechanical properties of bone tissue, the healing period postsurgery, the pathophysiology and toxicology of the alloying elements being discussed. The strategy in the future development of biomedical Mg alloys was proposed.

  14. Recent research and developments on wrought magnesium alloys

    Directory of Open Access Journals (Sweden)

    Sihang You

    2017-09-01

    Full Text Available Wrought magnesium alloys attract special interests as lightweight structural material due to their homogeneous microstructure and enhanced mechanical properties compared to as-cast alloys. In this contribution, recent research and developments on wrought magnesium alloys are reviewed from the viewpoint of the alloy design, focusing on Mg-Al, Mg-Zn and Mg-rare earth (RE systems. The effects of different alloying elements on the microstructure and mechanical properties are described considering their strengthening mechanisms, e.g. grain refinement, precipitation and texture hardening effect. Finally, the new alloy design and also the future research of wrought magnesium alloys to improve their mechanical properties are discussed.

  15. Development of Metallic Sensory Alloys

    Science.gov (United States)

    Wallace Terryl A.; Newman, John A.; Horne, Michael R.; Messick, Peter L.

    2010-01-01

    Existing nondestructive evaluation (NDE) technologies are inherently limited by the physical response of the structural material being inspected and are therefore not generally effective at the identification of small discontinuities, making the detection of incipient damage extremely difficult. One innovative solution to this problem is to enhance or complement the NDE signature of structural materials to dramatically improve the ability of existing NDE tools to detect damage. To address this need, a multifunctional metallic material has been developed that can be used in structural applications. The material is processed to contain second phase sensory particles that significantly improve the NDE response, enhancing the ability of conventional NDE techniques to detect incipient damage both during and after flight. Ferromagnetic shape-memory alloys (FSMAs) are an ideal material for these sensory particles as they undergo a uniform and repeatable change in both magnetic properties and crystallographic structure (martensitic transformation) when subjected to strain and/or temperature changes which can be detected using conventional NDE techniques. In this study, the use of a ferromagnetic shape memory alloy (FSMA) as the sensory particles was investigated.

  16. Vibrational entropies in metallic alloys

    Science.gov (United States)

    Ozolins, Vidvuds; Asta, Mark; Wolverton, Christopher

    2000-03-01

    Recently, it has been recognized that vibrational entropy can have significant effects on the phase stability of metallic alloys. Using density functional linear response calculations and molecular dynamics simulations we study three representative cases: (i) phase diagram of Al-rich Al-Sc alloys, (ii) stability of precipitate phases in CuAl_2, and (iii) phonon dynamics in bcc Zr. We find large vibrational entropy effects in all cases. In the Al-Sc system, vibrations increase the solid solubility of Sc in Al by decreasing the stability of the L12 (Al_3Sc) phase. This leads to a nearly ten-fold increase in the solid solubility of Sc in Al at T=800 K. In the Cu-Al system, our calculations predict that the tetragonal Laves phase of CuAl2 has 0.35 kB/atom higher vibrational entropy than the cubic CaF_2-type phase (the latter is predicted to be the T=0 K ground state of CuAl_2). This entropy difference causes a structural transformation in CuAl2 precipitates from the fluorite to the tetragonal Laves phase around T=500 K. Finally, we analyze the highly unusual dynamics of anharmonically stabilized bcc Zr, finding large diffuse-scattering intensity streaks between the bcc Bragg peaks.

  17. Abridgment of nano and micro length scale mechanical properties of novel Mg–9Li–7Al–1Sn and Mg–9Li–5Al–3Sn–1Zn alloys using object oriented finite element modeling

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Ankur [Department of Materials Science and Engineering, Indian Institute of Technology, Kanpur 208016 (India); Advanced Materials Processing and Analysis Center, Department of Materials Science and Engineering, University of Central Florida, Orlando, FL 32826 (United States); Kumar, Vinod [Department of Materials Science and Engineering, Indian Institute of Technology, Kanpur 208016 (India); Department of Metallurgical and Materials Engineering, Malaviya National Institute of Technology, Jaipur 302017 (India); Nair, Jitin [Department of Materials and Metallurgical Engineering, National Institute of Foundry and Forge Technology, Ranchi 834003 (India); Bansal, Ankit [Department of Materials Science and Engineering, Indian Institute of Technology, Kanpur 208016 (India); Tata Steel Ltd., Jamshedpur, Jharkhand 831001 (India); Balani, Kantesh, E-mail: kbalani@iitk.ac.in [Department of Materials Science and Engineering, Indian Institute of Technology, Kanpur 208016 (India)

    2015-06-15

    Highlights: • Dual phase (α + β) Mg–9Li–7Al–1Sn (LAT971) and Mg–9Li–5Al–3Sn–1Zn (LATZ9531) alloys. • Effective elastic modulus estimated from finite element method (FEM). • Correlation of nanoscale mechanical data with microstress distribution. • Precipitates of Mg–Al–Li act as stress relaxer and Mg–Li–Sn as stress concentrator. • Higher local heterogeneous stress distribution (∼0.6–5.7 GPa) in LATZ9531 alloys. - Abstract: In the recent years, magnesium–lithium (Mg–Li) alloys have attracted considerable attention/interest due to their high strength-to-density ratio and damping characteristic; and have found potential use in structural and biomedical applications. Here the mechanical behavior of novel Mg–9 wt.% Li–7 wt.% Al–1 wt.% Sn (LAT971) and Mg–9 wt.% Li–5 wt.% Al–3 wt.% Sn–1 wt.% Zn (LATZ9531) alloys is reported. Both, as cast and thermomechanically processed alloys have been studied which possess dual phase microstructure. Nanoindentation data have been utilized to envisage the elastic modulus of alloy via various micromechanics models (such as rule of mixtures, Voigt–Reuss, Cox model, Halpin–Tsai and Guth model) in order to estimate the elastic modulus. Object oriented finite element modeling (FEM) has been performed to predict stress distribution under tensile and compressive strain state. Close match between Halpin–Tsai model and FEM results show the abridgment of nano length scale property to evolution of microscopic stress distribution in novel LAT971 and LATZ9531 Mg–Li–Al based alloys.

  18. Structural alloys for high field superconducting magnets

    International Nuclear Information System (INIS)

    Morris, J.W. Jr.

    1985-08-01

    Research toward structural alloys for use in high field superconducting magnets is international in scope, and has three principal objectives: the selection or development of suitable structural alloys for the magnet support structure, the identification of mechanical phenomena and failure modes that may influence service behavior, and the design of suitable testing procedures to provide engineering design data. This paper reviews recent progress toward the first two of these objectives. The structural alloy needs depend on the magnet design and superconductor type and differ between magnets that use monolithic and those that employ force-cooled or ICCS conductors. In the former case the central requirement is for high strength, high toughness, weldable alloys that are used in thick sections for the magnet case. In the latter case the need is for high strength, high toughness alloys that are used in thin welded sections for the conductor conduit. There is productive current research on both alloy types. The service behavior of these alloys is influenced by mechanical phenomena that are peculiar to the magnet environment, including cryogenic fatigue, magnetic effects, and cryogenic creep. The design of appropriate mechanical tests is complicated by the need for testing at 4 0 K and by rate effects associated with adiabatic heating during the tests. 46 refs

  19. Aeronautical requirements for Inconel 718 alloy

    Science.gov (United States)

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

    2017-06-01

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

  20. Effect of neutron irradiation on vanadium alloys

    International Nuclear Information System (INIS)

    Braski, D.N.

    1986-01-01

    Neutron-irradiated vanadium alloys were evaluated for their susceptibility to irradiation hardening, helium embrittlement, swelling, and residual radioactivity, and the results were compared with those for the austenitic and ferritic stainless steels. The VANSTAR-7 and V-15Cr-5Ti alloys showed the greatest hardening between 400 and 600 0 C while V-3Ti-1Si and V-20Ti had lower values that were comparable to those of ferritic steels. The V-15Cr-5Ti and VANSTAR-7 alloys were susceptible to helium embrittlement caused by the combination of weakened grain boundaries and irradiation-hardened grain matrices. Specimen fractures were entirely intergranular in the most severe instances of embrittlement. The V-3Ti-1Si and V-20Ti alloys were more resistant to helium embrittlement. Except for VANSTAR-7 irradiated to 40 dpa at 520 0 C, all of the vanadium alloys exhibited low swelling that was similar to the ferritic steels. Swelling was greater in specimens that were preimplanted with helium using the tritium trick. The vanadium alloys clearly exhibit lower residual radioactivity after irradiation than the ferrous alloys