WorldWideScience

Sample records for invar

  1. Intersite elastic coupling and invar effect

    OpenAIRE

    Khomskii, D. I.; Kusmartsev, F. V.

    2004-01-01

    The invar phenomenon (very small thermal expansion in some iron alloys or compounds) is usually explained by the thermally-induced transitions between different spin states of Fe, having different atomic volumes. We consider these processes taking into account elastic interaction between Fe atoms in different spin states. Inclusion of these interactions explains why thermal expansion may be close to zero in a broad temperature interval and thus gives rise to the invar effect.

  2. Invar, AF-Invar, Anti-Invar and Martensite in FCC Fe-Based Alloys : An Attempt to Order this Chaos

    OpenAIRE

    Wassermann, E.; Entel, P.

    1995-01-01

    Systematics concerning magnetic and structural phase transitions within Fe-based sytems can be achieved if experimental data are analyzed as a function of composition and the atomic volume. The findings can be understood from calculations of the exchange coupling of pure fcc Fe as a function of the n.n. distance. Decisive is that the volume increase going along with Invar, AF-Invar, Anti-Invar as well as martensite transitions originates from a charge transfer between antibonding electronic o...

  3. Precipitation Hardening of Castable Iron-Nickel Invars

    Science.gov (United States)

    Ogorodnikova, O. M.; Maksimova, E. V.

    2015-07-01

    Hardening of castable iron-nickel invars due to alloying with carbide-forming elements and carbon and subsequent heat treatment is investigated. It is shown that the strength of the invar alloys can be increased without raising the low values of the temperature coefficient of linear expansion.

  4. Ultra high purity, dimensionally stable INVAR 36

    Science.gov (United States)

    Sokolowski, Witold M. (Inventor); Lane, Marc S. (Inventor); Hsieh, Cheng H. (Inventor); Odonnell, Timothy P. (Inventor)

    1995-01-01

    An INVAR 36 material having long-term dimensional stability is produced by sintering a blend of powders of nickel and iron under pressure in an inert atmosphere to form an alloy containing less than 0.01 parts of carbon and less than 0.1 part aggregate and preferably 0.01 part individually of Mn, Si, P, S and Al impurities. The sintered alloy is heat treated and slowly and uniformly cooled to form a material having a coefficient of thermal expansion of less than 1 ppm/C and a temporal stability of less than 1 ppm/year.

  5. Anisotropic Thermal Expansion and Cooperative Invar and Anti-Invar Effects in Mn Alloys

    Science.gov (United States)

    Yokoyama, Toshihiko; Eguchi, Keitaro

    2013-02-01

    We have investigated thermal expansion of a tetragonal Mn88Ni12 alloy by x-ray diffraction, Mn and Ni K-edge extended x-ray-absorption fine-structure spectroscopy, and the computational simulations based on the path-integral effective-classical-potential theory. It is found from the x-ray diffraction that the tetragonal lattice constant c exhibits almost no thermal expansion like an Invar alloy, while the lattice constant a shows even larger thermal expansion than usually expected from anharmonicity, implying significant anisotropy in thermal expansion. The extended x-ray-absorption fine-structure reveals that the Mn local environment is actually tetragonally distorted, while the Ni one retains its inherent cubiclike symmetry. Combined with the computational simulations, it is concluded that large thermal expansion along the a axis originates from the anti-Invar effect, while negligibly small thermal expansion along the c axis originates from the cooperative Invar effect. Namely, the tetragonally distorted more stable antiferromagnetic Mn state gives a significantly smaller (slightly longer) atomic radius along the a (c) axis than the radius of the spherical paramagnetic state.

  6. Bonded Invar Clip Removal Using Foil Heaters

    Science.gov (United States)

    Pontius, James T.; Tuttle, James G.

    2009-01-01

    A new process uses local heating and temperature monitoring to soften the adhesive under Invar clips enough that they can be removed without damaging the composite underneath or other nearby bonds. Two 1x1 in. (approx.2.5x2.5 cm), 10-W/sq in. (approx.1.6-W/sq cm), 80-ohm resistive foil Kapton foil heaters, with pressure-sensitive acrylic adhesive backing, are wired in parallel to a 50-V, 1-A limited power supply. At 1 A, 40 W are applied to the heater pair. The temperature is monitored in the clip radius and inside the tube, using a dual thermocouple readout. Several layers of aluminum foil are used to speed the heat up, allowing clips to be removed in less than five minutes. The very local heating via the foil heaters allows good access for clip removal and protects all underlying and adjacent materials.

  7. Magnetochemical origin for Invar anomalies in iron-nickel alloys

    Science.gov (United States)

    Crisan, V.; Entel, P.; Ebert, H.; Akai, H.; Johnson, D. D.; Staunton, J. B.

    2002-07-01

    Zero- and finite-temperature (T) first-principles calculations versus composition (c) show that magnetochemical effects lead to Invar anomalies in Fe-(Ni, Co, Pt) alloys. Chemical short- or long-range order and negative interatomic exchange interaction of electrons in antibonding majority-spin states force the face-centered-cubic lattice to compete simultaneously for a smaller volume (from antiferromagnetic tendencies) and a larger volume (from Stoner ferromagnetic tendencies). The resulting additional negative lattice anharmonicity is very large for Fe-(Ni, Co) while absent for Fe-Pt. Our results explain the T- and c-dependent behavior of Invar properties, including the lattice softening and thermal expansion of Fe-Ni. In addition, the occurrence of a noncollinear spin structure at T=0 K near Invar can be understood on the basis of our results.

  8. Microstructure and Plastic Deformation of the As-Welded Invar Fusion Zones

    Science.gov (United States)

    Yao, D. J.; Zhou, D. R.; Xu, P. Q.; Lu, F. G.

    2017-05-01

    The as-welded Invar fusion zones were fabricated between cemented carbides and carbon steel using a Fe-Ni Invar interlayer and laser welding method. Three regions in the as-welded Invar fusion zones were defined to compare microstructures, and these were characterized and confirmed by scanning electron microscopy and X-ray diffractometry. The structure and plastic deformation mechanism for initial Invar Fe-Ni alloys and the as-welded Invar fusion zones are discussed. (1) After undergoing high-temperature thermal cycles, the microstructure of the as-welded Invar fusion zones contains γ-(Fe, Ni) solid solution (nickel dissolving in γ-Fe) with a face-centered cubic (fcc) crystal structure and mixed carbides (eutectic colonies, mixed carbides between two adjacent grains). The mixed carbides exhibited larger, coarser eutectic microstructures with a decrease in welding speed and an increase in heat input. (2) The structure of the initial Invar and the as-welded Invar is face-centered cubic γ-(Fe, Ni). (3) The as-welded Invar has a larger plastic deformation than initial Invar with an increase in local strain field and dislocation density. Slip deformation is propagated along the (111) plane. This finding helps us to understand microstructure and the formation of dislocation and plastic deformation when the Invar Fe-Ni alloy undergoes a high-temperature process.

  9. Experience of precision measuring distances by invar wires at accelerators

    International Nuclear Information System (INIS)

    Porubaj, N.I.

    1977-01-01

    With a view to determining the deformations and displacements of the ring foundation of the ITEP accelerator, the method of very accurate distance measurements by means of invar wires and strips is described. Measurement errors are analyzed. This method has allowed to measure distances up to 40 m with a mean-square error of less than 40 μm. The calibration accuracy of 3 and 25-m measuring wires has been determined to be +- 27 μm. Time instability of the wires is +- 16 μm. It is shown that strips are more stable in time than wires. Elongation of 6, 19, 25 and 38 m invar wires has been measured as function of the tension time. The error due to tension of a 38-m wire may be tangible. Data on thermal coefficient variation in time has been obtained for invar wires and strips. The multiannual measurements of the ring foundation deformations show that variations of the mean radius are caused by increases of concrete temperature. Temperature increase by only 1 deg caused mean radius increase of 0.3 mm

  10. ANTIFERROMAGNETISM OF THE Fe-Ni ALLOYS IN THE INVAR COMPOSITION

    OpenAIRE

    Tino, Y.

    1988-01-01

    Antiferromagnetism of the Fe-Ni Invar alloys was studied mainly by Mössbauer spectroscopy. It is seen that various hyperfine fields are superposed there, and that the superposition becomes larger with increasing cold-working. This causes amorphous-like structures, which leads to various incomplete antiferromagnetism coming from the magnetic forces, originating the Invar anomaly.

  11. Structure and Compressive Properties of Invar-Cenosphere Syntactic Foams

    OpenAIRE

    Dung Luong; Dirk Lehmhus; Nikhil Gupta; Joerg Weise; Mohamed Bayoumi

    2016-01-01

    The present study investigates the mechanical performance of syntactic foams produced by means of the metal powder injection molding process having an Invar (FeNi36) matrix and including cenospheres as hollow particles at weight fractions (wt.%) of 5 and 10, respectively, corresponding to approximately 41.6 and 60.0 vol.% in relation to the metal content and at 0.6 g/cm(3) hollow particle density. The synthesis process results in survival of cenospheres and provides low density syntactic foam...

  12. Structure and Compressive Properties of Invar-Cenosphere Syntactic Foams

    Directory of Open Access Journals (Sweden)

    Dung Luong

    2016-02-01

    Full Text Available The present study investigates the mechanical performance of syntactic foams produced by means of the metal powder injection molding process having an Invar (FeNi36 matrix and including cenospheres as hollow particles at weight fractions (wt.% of 5 and 10, respectively, corresponding to approximately 41.6 and 60.0 vol.% in relation to the metal content and at 0.6 g/cm3 hollow particle density. The synthesis process results in survival of cenospheres and provides low density syntactic foams. The microstructure of the materials is investigated as well as the mechanical performance under quasi-static and high strain rate compressive loads. The compressive stress-strain curves of syntactic foams reveal a continuous strain hardening behavior in the plastic region, followed by a densification region. The results reveal a strain rate sensitivity in cenosphere-based Invar matrix syntactic foams. Differences in properties between cenosphere- and glass microsphere-based materials are discussed in relation to the findings of microstructural investigations. Cenospheres present a viable choice as filler material in iron-based syntactic foams due to their higher thermal stability compared to glass microspheres.

  13. Structure and Compressive Properties of Invar-Cenosphere Syntactic Foams.

    Science.gov (United States)

    Luong, Dung; Lehmhus, Dirk; Gupta, Nikhil; Weise, Joerg; Bayoumi, Mohamed

    2016-02-18

    The present study investigates the mechanical performance of syntactic foams produced by means of the metal powder injection molding process having an Invar (FeNi36) matrix and including cenospheres as hollow particles at weight fractions (wt.%) of 5 and 10, respectively, corresponding to approximately 41.6 and 60.0 vol.% in relation to the metal content and at 0.6 g/cm³ hollow particle density. The synthesis process results in survival of cenospheres and provides low density syntactic foams. The microstructure of the materials is investigated as well as the mechanical performance under quasi-static and high strain rate compressive loads. The compressive stress-strain curves of syntactic foams reveal a continuous strain hardening behavior in the plastic region, followed by a densification region. The results reveal a strain rate sensitivity in cenosphere-based Invar matrix syntactic foams. Differences in properties between cenosphere- and glass microsphere-based materials are discussed in relation to the findings of microstructural investigations. Cenospheres present a viable choice as filler material in iron-based syntactic foams due to their higher thermal stability compared to glass microspheres.

  14. Invar hardening under keeping of low values of temperature coefficient of linear expansion

    International Nuclear Information System (INIS)

    Bashnin, Yu.A.; Shiryaeva, A.N.; Omel'chenko, A.V.

    1982-01-01

    Complex invar alloying with chromium, zirconium and nitrogen is conducted for increasing hardness and assuring low values of the temperature coefficient of linear expansion. It is shown that alloying with nitride-forming elements-chromium, zirconium and the following high-temperature saturation under high pressure with nitrogen provides the invar hardening at assuring a low temperature coefficient of linear expansion. Saturation with nitrogen under 100 MPa pressure at 1050 deg C during 3 hours permits to prepare an invar containing up to 0.2% N 2 uniformly distributed over the whole cross section of samples with 4 mm diameter. Nitrogen in invar alloys alloyed with chromium and zirconium affects the Curie point similarly to carbon and nickel shifting it towards higher temperatures, it slightly changes the value of the temperature coefficient of linear expansion and provides linear character of thermal expansion dependence on temperature in the +100 deg C - -180 deg C range

  15. A common magnetic origin for the Invar effects in fcc iron-based ferromagnets

    Science.gov (United States)

    Hooley, Chris; Liot, Francois

    2011-03-01

    Using first-principles calculations, in conjunction with Ising magnetism, we undertake a theoretical study to elucidate the origin of the experimentally observed Invar effects in disordered fcc iron-based ferromagnets. First, we show that our theory can account for the Invar effects in iron-nickel alloys, the anomalies being driven by the magnetic contributions to the average free energies. Second, we present evidence indicating that the relationship between thermal expansion and magnetism is essentially the same in all the studied alloys, including those which display the Invar effect and those which do not. Hence we propose that magnetism plays a crucial role in determining whether a system exhibits normal thermal expansion, the Invar effect, or something else. The crucial determining factor is the rate at which the relative orientation of the local magnetic moments of nearest-neighbor iron atoms fluctuates as the system is heated.

  16. Pressure-induced Invar effect in Fe-Ni alloys.

    Science.gov (United States)

    Dubrovinsky, L; Dubrovinskaia, N; Abrikosov, I A; Vennström, M; Westman, F; Carlson, S; van Schilfgaarde, M; Johansson, B

    2001-05-21

    We have measured the pressure-volume (P-V) relations for cubic iron-nickel alloys for three different compositions: Fe 0.64Ni (0.36), Fe 0.55Ni (0.45), and Fe 0.20Ni (0.80). It is observed that for a certain pressure range the bulk modulus does not change or can even decrease to some minimum value, after which it begins to increase under still higher pressure. In our experiment, we observe for the first time a new effect, namely, that the Fe-Ni alloys with high Ni concentrations, which show positive thermal expansion at ambient pressure, become Invar system upon compression over a certain pressure range.

  17. Selective laser melting of Invar 36: Microstructure and properties

    International Nuclear Information System (INIS)

    Qiu, Chunlei; Adkins, Nicholas J.E.; Attallah, Moataz M.

    2016-01-01

    Invar 36 samples have been fabricated by selective laser melting at a constant laser power but with varied laser scanning speeds. Some samples were further heat treated or hot isostatically pressed (HIPed). The obtained microstructures were studied using optical and electron microscopes, X-ray diffraction and electron backscatter diffraction techniques and the properties evaluated through both tensile testing and thermal expansion measurement. It was found that the as-fabricated samples show very low porosity (<0.5%) when the laser scanning speeds are below 3200 mm/s but show remarkably increased porosity above 3200 mm/s (at 400 W). Increased scanning speed also led to increasingly irregular-shaped laser scanned tracks together with an increased number of pores on sample surfaces and keyhole features within the samples, all indicative of increasingly unstable melt flow behaviour. The as-fabricated microstructure was dominated by columnar γ grains decorated by nanosized α precipitates, resulting in development of texture. Heat treatment did not change microstructure significantly while HIPing closed the majority of pores but also caused pronounced coarsening of α precipitates especially those located at grain boundaries during subsequent slow cooling. With the presence of elongated pores, the vertically built samples were found to show much lower elongation than horizontally built samples while in the absence of pores their ductility has been significantly improved but their tensile strengths are still lower than the latter. The vertically built samples generally failed in a transgranular mode while the horizontally built samples failed in an intergranular mode. HIPing greatly degraded tensile properties due to the presence of coarse grain boundary α precipitates weakening the bonding between grains. Irrespective of building orientations, the as-fabricated samples show low coefficients of thermal expansion below 300 °C comparable to conventionally

  18. Unusually sharp paramagnetic phase transition in thin film Fe3Pt invar

    Science.gov (United States)

    Drisko, Jasper; Cumings, John

    2013-03-01

    Invar alloys, typically 3d transition metal rich systems, are most commonly known for their extremely low coefficients of thermal expansion (CTE) over a wide range of temperatures close to room temperature. This anomalous behavior in the CTE lends Invar to a variety of important applications in precision mechanical devices, scientific instruments, and sensors, among others. Many theoretical models of Invar have been proposed over the years, the most promising of which is a system described by two coexisting phases, one high-spin high-volume and the other low-spin low-volume, that compete to stabilize the volume of the material as the temperature is changed. However, no theory has yet been able to explain all experimental observations across the range of Invar alloys, especially at finite temperature. We have fabricated thin films of a Fe3Pt Invar alloy and investigate them using Lorentz Transmission Electron Microscopy (TEM). 23nm films are deposited onto SiN membrane substrates via radio-frequency magnetron sputtering from a pure Fe target decorated with Pt pieces. We observe novel magnetic domain structures and an unusually sharp phase transition between ferromagnetic (FM) and paramagnetic (PM) regions of the film under a temperature gradient. This sharp transition suggests that the FM-to-PM transition may be first order, perhaps containing a structural-elastic component to the order parameter. However, electron diffraction reveals that both the FM and PM regions have the same FCC crystal structure.

  19. Observation of etch pits in Fe-36wt%Ni Invar alloy

    Science.gov (United States)

    Lu, Dong-zhu; Wu, Min-jie

    2014-07-01

    To indirectly investigate the dislocation behavior of Fe-36wt%Ni Invar alloy by the etch pit method, polished Invar specimens were etched by a solution containing 4 g copper sulfate, 20 mL hydrochloric acid, and 20 mL deionized water for 2 min. Etch pits in the etched surfaces were observed. All the etch pits in one specific grain exhibited similar shapes, which are closely related to the grain orientations. These etch pits were characterized as dislocation etch pits. It was observed that etch pits arranged along grain boundaries, gathered at grain tips and strip-like etch pit clusters passed through a number of grains in the pure Invar specimens. After the addition of a small amount of alloying elements, the identification of a single dislocation etch pit is challenging compared with the pure Invar alloy. Thus, the observation of etch pits facilitates the investigation on the dislocation behavior of the pure Invar alloy. In addition, alloying elements may affect the densities and sizes of etch pits.

  20. Critical femtosecond laser parameters for the fabrication of optimal reflecting diffraction gratings on Invar36

    Science.gov (United States)

    Mohammad Hossein, Goudarzi; Meng-Jyun, Lin; Ji-Bin, Horng; Jeng-Ywan, Jeng

    2016-06-01

    This paper discusses the effect of femtosecond laser parameters on Invar36, and the efficiency of reflecting diffraction gratings on the alloy. Several gratings were made with different laser parameters in two regimes: constant repetition rates and constant average laser power on the Invar surface. The efficiency of diffraction gratings is measured in an off-plane configuration by determining the power of diffracted points. With the constant average power technique, an increase in laser influence decreased the ablation depth of lines and increased the line widths. The discoloration of line edges from increasing the laser influence more than 0.57 J /cm2 decreased the grating efficiency by over 49%. It was also found that increasing the repetition rate enhanced the grating efficiency and increasing the average power decreased the efficiency. In addition, the ablation threshold of Invar is 0.122 J /cm2 when the number of pulses (NOP) equals 389.

  1. Low Temperature Transformation of Fe-Pd and Fe-Pt Invar Alloys

    OpenAIRE

    Masaaki, Matsui; Kengo, Adachi; Hidefumi, Asano; Department of Iron and Steel Engineering, Faculty of Engineering Nagoya University; Department of Iron and Steel Engineering, Faculty of Engineering Nagoya University; Department of Iron and Steel Engineering, Faculty of Engineering Nagoya University

    1981-01-01

    Low temperature structures of Fe-Pd and Fe-Pt alloys in the Invar region have been determined by means of low temperature X-ray diffraction experiment. The phase diagrams are obtained. A new fct phase is found in the ordered and disordered Fe-Pt and the disordered Fe-Pd systems. An effect of the degree of order for Fe_3Pt to the structural transformations are examined. The lattice instability of Fe-based fcc Invar alloys are discussed from the low temperature structures with the lattice softe...

  2. Pulse electrochemical machining on Invar alloy: Optical microscopic/SEM and non-contact 3D measurement study of surface analyses

    Science.gov (United States)

    Kim, S. H.; Choi, S. G.; Choi, W. K.; Yang, B. Y.; Lee, E. S.

    2014-09-01

    In this study, Invar alloy (Fe 63.5%, Ni 36.5%) was electrochemically polished by PECM (Pulse Electro Chemical Machining) in a mixture of NaCl, glycerin, and distilled water. A series of PECM experiments were carried out with different voltages and different electrode shapes, and then the surfaces of polished Invar alloy were investigated. The polished Invar alloy surfaces were investigated by optical microscope, scanning electron microscope (SEM), and non-contact 3D measurement (white light microscopes) and it was found that different applied voltages produced different surface characteristics on the Invar alloy surface because of the locally concentrated applied voltage on the Invar alloy surface. Moreover, we found that the shapes of electrode also have an effect on the surface characteristics on Invar alloy surface by influencing the applied voltage. These experimental findings provide fundamental knowledge for PECM of Invar alloy by surface analysis.

  3. Microstructures and Properties of 40Cu/Ag(Invar) Composites Fabricated by Powder Metallurgy and Subsequent Thermo-Mechanical Treatment

    Science.gov (United States)

    Zhang, Xin; Huang, Yingqiu; Liu, Xiangyu; Yang, Lei; Shi, Changdong; Wu, Yucheng; Tang, Wenming

    2018-03-01

    Composites of 40Cu/Ag(Invar) were prepared via pressureless sintering and subsequent thermo-mechanical treatment from raw materials of electroless Ag-plated Invar alloy powder and electrolytic Cu powder. Microstructures and properties of the prepared composites were studied to evaluate the effect of the Ag layer on blocking Cu/Invar interfacial diffusion in the composites. The electroless-plated Ag layer was dense, uniform, continuous, and bonded tightly with the Invar alloy substrate. During sintering of the composites, the Ag layer effectively prevented Cu/Invar interfacial diffusion. During cold-rolling, the Ag layer was deformed uniformly with the Invar alloy particles. The composites exhibited bi-continuous network structure and considerably improved properties. After sintering at 775 °C and subsequent thermo-mechanical treatment, the 40Cu/Ag(Invar) composites showed satisfactory comprehensive properties: relative density of 99.0 pct, hardness of HV 253, thermal conductivity of 55.7 W/(m K), and coefficient of thermal expansion of 11.2 × 10-6/K.

  4. Quadrilateral Micro-Hole Array Machining on Invar Thin Film: Wet Etching and Electrochemical Fusion Machining.

    Science.gov (United States)

    Choi, Woong-Kirl; Kim, Seong-Hyun; Choi, Seung-Geon; Lee, Eun-Sang

    2018-01-19

    Ultra-precision products which contain a micro-hole array have recently shown remarkable demand growth in many fields, especially in the semiconductor and display industries. Photoresist etching and electrochemical machining are widely known as precision methods for machining micro-holes with no residual stress and lower surface roughness on the fabricated products. The Invar shadow masks used for organic light-emitting diodes (OLEDs) contain numerous micro-holes and are currently machined by a photoresist etching method. However, this method has several problems, such as uncontrollable hole machining accuracy, non-etched areas, and overcutting. To solve these problems, a machining method that combines photoresist etching and electrochemical machining can be applied. In this study, negative photoresist with a quadrilateral hole array pattern was dry coated onto 30-µm-thick Invar thin film, and then exposure and development were carried out. After that, photoresist single-side wet etching and a fusion method of wet etching-electrochemical machining were used to machine micro-holes on the Invar. The hole machining geometry, surface quality, and overcutting characteristics of the methods were studied. Wet etching and electrochemical fusion machining can improve the accuracy and surface quality. The overcutting phenomenon can also be controlled by the fusion machining. Experimental results show that the proposed method is promising for the fabrication of Invar film shadow masks.

  5. Effect of Cold Drawing and Heat Treatment on the Microstructure of Invar36 Alloy Wire

    International Nuclear Information System (INIS)

    Han, Seung Youb; Jang, Seon Ah; Eun, Hee-Chul; Choi, Jung-Hoon; Lee, Ki Rak; Park, Hwan Seo; Ahn, Do-Hee; Kim, Soo Young; Kim, Jea Youl; Shin, Sang Yong

    2016-01-01

    In this study, the effect of cold drawing and heat treatment on the microstructure of Invar36 alloy wire was investigated. Invar36 alloy wire is used as a transmission line core material, and is required to have high strength. The diameter of the Invar36 alloy wire specimens were reduced from 16 mm to 4.3 mm after three cold drawing and two heat treatment processes, thereby increasing tensile strength. Specimens were taken after each of the cold drawing and heat treatment processes, and their microstructure and tensile properties were analyzed. The Invar36 alloy wire had a γ-(Fe, Ni) phase matrix before the cold drawing and heat treatment processes. After the cold drawing processes, {220} and {200} textures were mainly achieved. After the heat treatment processes, a {200} recrystallization γ-(Fe, Ni) phase was formed with fine carbides. The recrystallization γ-(Fe, Ni) phase grains had low dislocation density, so they probably accommodated a large amount of deformation during the cold drawing processes.

  6. Invar Effect and non-collinear magnetism in FeCu alloys

    Energy Technology Data Exchange (ETDEWEB)

    Eisenbach, Markus [ORNL; Stocks, George Malcolm [ORNL

    2009-01-01

    The Invar effect has been observed in many Fe rich alloys, most famously Ni Invar. Generally the Invar behavior is associated with the strong coupling between the lattice and magnetic degrees of freedom, and therefore depends on the magnetic ordering in these alloys. Recent experimental works observed an Invar effect in fcc-FeCu solid solutions. In the present paper the magnetic states of fcc-FeCu solid solutions for various concentrations is investigated. The first principles calculations employ the locally selfconsistent multiple scattering (LSMS) real space method for solving the LDA Kohn-Sham equation to investigate the non collinear ordering of magnetic moments. The magnetic order for the low iron concentration is fount to be non-collinear, spin glass like, and the ferromagnetic order is not stable, whereas for the iron rich alloys for the ground state equilibrium lattice constants a magnetic order with parallel aligned Fe moments is stable. In this configuration the induced moments at the Cu sites order nontrivially on a cone with an opening of approximately 40 degrees around the Fe moment direction.

  7. Stress-induced large Curie temperature enhancement in Fe(sub 64)Ni(sub 36) Invar alloy.

    Energy Technology Data Exchange (ETDEWEB)

    Gorria, P.; Martinez-Blanco, D.; Perez, M. J.; Blanco, J. A.; Hernando, A.; Laguna-Marco, M. A.; Haskel, D.; Souza-Neto, N. M.; Xmith, R. I.; Marshall, W. G.; Garbarino, G.; Mezouar, M.; Fernandez-Martinez, A.; Chaboy, J.; Fernandez Barquin, L.; Rodriguez Castrillon, J. A.; Moldovan, M.; Garcia Alonso, J. I.; Zhang, J.; Llobet, A.; Jiang, J. S.; Univ. de Oviedo; Inst. de Magnetismo Aplicado; ISIS Facility; ESRF; Univ.Grenoble and CNRS; CSIC-Univ. de Zaragoza; Univ. de Cantabria; LANL

    2009-01-01

    We have succeeded in increasing up to 150 K the Curie temperature in the Fe{sub 64}N{sub 36}6 invar alloy by means of a severe mechanical treatment followed by a heating up to 1073 K. The invar behavior is still present as revealed by the combination of magnetic measurements with neutron and x-ray techniques under extreme conditions, such as high temperature and high pressure. The proposed explanation is based in a selective induced microstrain around the Fe atoms, which causes a slight increase in the Fe-Fe interatomic distances, thus reinforcing ferromagnetic interactions due to the strong magnetoelastic coupling in these invar compounds.

  8. Anti-Invar properties and magnetic order in fcc Fe-Ni-C alloy

    Energy Technology Data Exchange (ETDEWEB)

    Nadutov, V.M., E-mail: nadvl@imp.kiev.ua [G.V. Kurdyumov Institute for Metal Physics of the N.A.S. of Ukraine, Kyiv (Ukraine); Kosintsev, S.G.; Svystunov, Ye.O. [G.V. Kurdyumov Institute for Metal Physics of the N.A.S. of Ukraine, Kyiv (Ukraine); Garamus, V.M.; Willumeit, R.; Eckerlebe, H. [GKSS Research Center, Geesthacht (Germany); Ericsson, T.; Annersten, H. [Uppsala University, Uppsala (Sweden)

    2011-11-15

    Anti-Invar effect was revealed in the fcc Fe-25.3%Ni-0.73%C (wt%) alloy, which demonstrates high values of thermal expansion coefficient (TEC) (15-21)x10{sup -6} K{sup -1} accompanied by almost temperature-insensitive behavior in temperature range of 122-525 K. Alloying with carbon considerably expanded the low temperature range of anti-Invar behavior in fcc Fe-Ni-based alloy. The Curie temperature of the alloy T{sub C}=195 K was determined on measurements of temperature dependences of magnetic susceptibility and saturation magnetization. The Moessbauer and small-angle neutron scattering (SANS) experiments on the fcc Fe-25.3%Ni-(0.73-0.78)%C alloys with the varying temperatures below and above the Curie point and in external magnetic field of 1.5-5 T were conducted. Low value of the Debye temperature {Theta}{sub D}=180 K was estimated using the temperature dependence of the integral intensity of Moessbauer spectra for specified temperature range. The inequality B{sub eff}=(0.7-0.9)B{sub ext} was obtained in external field Moessbauer measurement that points to antiferromagnetically coupled Fe atoms, which have a tendency to align their spins perpendicular to B{sub ext}. Nano length scale magnetic inhomogeneities nearby and far above T{sub C} were revealed, which assumed that it is caused by mixed antiferromagnetically and ferromagnetically coupled Fe atom spins. The anti-Invar behavior of Fe-Ni-C alloy is explained in terms of evolution of magnetic order with changing temperature resulting from thermally varied interspin interaction and decreasing stiffness of interatomic bond. - Highlights: > Anti-Invar effect was revealed in the fcc Fe-25.3%Ni-0.73%C (wt%) alloy. > Carbon expanded the temperature range of anti-Invar behavior in Fe-Ni-based alloy. > Moessbauer data point to mixed interspin interaction and low the Dedye temperature. > The SANS experiments reveal nano length scale magnetic inhomogeneities {<=}6 nm. > Anti-Invar behavior of Fe-Ni-C alloy explained by

  9. Abnormal grain growth in the nanostructured Invar alloy fabricated by electrodeposition

    Science.gov (United States)

    Park, Hyung-Ki; Hwang, Nong-Moon; Park, Yong Bum

    2012-11-01

    Abnormal grain growth in the nanostructured Invar alloy fabricated by electrodeposition was investigated by electron backscattered diffraction. The observation showed that most of grains growing abnormally during annealing at 380°C have Σ3 boundaries. The observation could be best explained by the mechanism of solid-state wetting, where the Σ3 boundary provides the low-energy boundary, which increases the probability of solid-state wetting, leading to exclusive growth.

  10. High-pressure magnetic study of Fe-Ni and Fe-Pt Invar alloys

    Czech Academy of Sciences Publication Activity Database

    Nataf, L.; Decremps, F.; Chervin, J.C.; Mathon, O.; Pascarelli, S.; Kamarád, Jiří; Baudelet,, F.; Congeduti, A.; Itié, J.P.

    2009-01-01

    Roč. 80, č. 13 (2009), 134404/1-134404/6 ISSN 1098-0121 R&D Projects: GA ČR GA202/09/1027 Institutional research plan: CEZ:AV0Z10100521 Keywords : high-pressure effects * Invar * magnetic circular dichroism, * magnetic moments * magnetic transitions * magnetisation * platinum alloys Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.475, year: 2009

  11. Effect of Rare Earth Yttrium on the Hot Ductility of Fe-36Ni Invar Alloy

    Science.gov (United States)

    Yu, Y. C.; Liu, H. T.; Chen, W. Q.; Zheng, H. G.

    2014-12-01

    The hot ductility of Fe-36Ni invar alloy doped with and without yttrium was investigated using a Gleeble-3800 thermal-mechanical simulator over the temperature range 850-1050 °C and the improvement mechanism of the hot ductility was analysed with a combination of SEM, EDS and OM. The results showed that Fe-36Ni invar alloy had a poor hot ductility below 1050 °C, which was mainly attributed to the presence of the grain boundary sliding and weak grain boundaries. The addition of 0.048% yttrium had a substantial improvement in the hot ductility of Fe-36Ni invar alloy over the whole testing temperature range especially at 950-1000 °C. At 850-900 °C, the improvement of the hot ductility was mainly associated with the grain boundary strengthening and the restriction of the grain boundary sliding because the addition of yttrium could reduce the segregation of sulfur at grain boundaries and refine the grain structure. At 950-1000 °C, the hot ductility was highly improved, which was owed to the acceleration and occurrence of dynamic recrystallization as a result of the refinement of the grain structure by addition of yttrium.

  12. The porosity formation mechanism in the laser-MIG hybrid welded joint of Invar alloy

    Science.gov (United States)

    Zhan, Xiaohong; Gao, Qiyu; Gu, Cheng; Sun, Weihua; Chen, Jicheng; Wei, Yanhong

    2017-10-01

    The porosity formation mechanism in the laser-metal inter gas (MIG) multi-layer hybrid welded (HW) joint of 19.05 mm thick Invar alloy is investigated. The microstructure characteristics and energy dispersive spectroscopy (EDS) are analyzed. The phase identification was conducted by the X-ray diffractometer (XRD). Experimental results show that the generation of porosity is caused by the relatively low laser power in the root pass and low current in the cover pass. It is also indicated that the microstructures of the welded joints are mainly observed to be columnar crystal and equiaxial crystal, which are closely related to the porosity formation. The EDS results show that oxygen content is significantly high in the inner wall of the porosity. The XRD results indicate that the BM and the WB of laser-MIG HW all are composed of Fe0.64Ni0.36 and γ-(Fe,Ni). When the weld pool is cooled quickly, [NiO] [FeO] and [MnO] are formed that react on C to generate CO/CO2 gases. The porosity of laser-MIG HW for Invar alloy is oxygen pore. The root source of metallurgy porosity formation is that the dissolved gases are hard to escape sufficiently and thus exist in the weld pool. Furthermore, 99.99% pure Argon is recommended as protective gas in the laser-MIG HW of Invar alloy.

  13. Atomistic modeling of thermodynamic properties of Pu-Ga alloys based on the Invar mechanism

    Science.gov (United States)

    Lee, Tongsik; Taylor, Christopher D.; Lawson, A. C.; Conradson, Steven D.; Chen, Shao Ping; Caro, A.; Valone, Steven M.; Baskes, Michael I.

    2014-05-01

    We present an atomistic model that accounts for a range of anomalous thermodynamic properties of the fcc δ phase of Pu-Ga alloys in terms of the Invar mechanism. Two modified embedded atom method potentials are employed to represent competing electronic states in δ-Pu, each of which has an individual configuration dependence as well as distinct interactions with gallium. Using classical Monte Carlo simulations, we compute the temperature dependence of various thermodynamic properties for different dilute gallium concentrations. The model reproduces the observed effects of excessive volume reduction along with a rapid shift in thermal expansion from negative to positive values with increasing gallium concentration. It also predicts progressive stiffening upon dilute-gallium alloying, while the calculated thermal softening is nearly independent of the gallium concentration in agreement with resonant ultrasound spectroscopy measurements in the literature. Analysis of the local structure predicted by the model indicates that the distribution of the gallium atoms is not completely random in the δ phase due to the presence of short-range order associated with the Invar mechanism. This effect is consistent with the nanoscale heterogeneity in local gallium concentration which is observed in recent extended x-ray absorption fine structure spectroscopy experiments. Implications of the Invar effect for phase stability and physical interpretations of the two states are also discussed.

  14. Effect of 50-keV proton irradiation on the magnetism of a Fe66Ni34 Invar alloy

    Science.gov (United States)

    Matsushita, M.; Matsushima, Y.; Uruga, T.; Ishigami, R.; Iwase, A.

    2013-05-01

    The magnetism of Fe-Ni Invar alloys is very sensitive to the lattice constant, stress, and the number of nearest-neighbor Fe-Fe atomic pairs. Ion irradiation is a useful tool to alter the local atomic structure of a given material. Therefore, the effects of low-energy and light-ion irradiation on the magnetism of a Fe66Ni34 Invar alloy were investigated in this study. The Fe66Ni34 Invar alloy was irradiated with 50-keV protons at a fluence of 1×1015 ions/cm2 at room temperature. The Curie temperature was found to increase from 465 K (before irradiation) to 535 K (after irradiation). The X-ray absorption analysis of the fine structure of the alloy revealed that irradiation had no effect on the atomic structures surrounding Fe and Ni.

  15. Linear thermal expansion coefficient of cast Fe-Ni invar and Fe-Ni-Co superinvar alloys

    International Nuclear Information System (INIS)

    Ogorodnikova, O.M.; Chermenskaya, E.V.; Rabinovich, S.V.; Grachev, S.V.

    1999-01-01

    Cast invar alloys Fe-Ni (28-35 wt. % Ni) are investigated using metallography, dilatometry and X-ray methods as soon as the crystallization is completed and again after low-temperature treatment resulting in martensitic transformation in low nickel alloys. Nickel distribution in a cast superinvar Fe-32% Ni-4% Co is studied by means of X-ray spectrum microanalysis. The results obtained permit the correction of model concepts about cast invars and the estimate of a coefficient of linear expansion depending on phase composition and nickel microsegregation [ru

  16. Anti-Invar properties and magnetic order in fcc Fe-Ni-C alloy

    Science.gov (United States)

    Nadutov, V. M.; Kosintsev, S. G.; Svystunov, Ye. O.; Garamus, V. M.; Willumeit, R.; Eckerlebe, H.; Ericsson, T.; Annersten, H.

    2011-11-01

    Anti-Invar effect was revealed in the fcc Fe-25.3%Ni-0.73%C (wt%) alloy, which demonstrates high values of thermal expansion coefficient (TEC) (15-21)×10 -6 K -1 accompanied by almost temperature-insensitive behavior in temperature range of 122-525 K. Alloying with carbon considerably expanded the low temperature range of anti-Invar behavior in fcc Fe-Ni-based alloy. The Curie temperature of the alloy TC=195 K was determined on measurements of temperature dependences of magnetic susceptibility and saturation magnetization. The Mössbauer and small-angle neutron scattering (SANS) experiments on the fcc Fe-25.3%Ni-(0.73-0.78)%C alloys with the varying temperatures below and above the Curie point and in external magnetic field of 1.5-5 T were conducted. Low value of the Debye temperature ΘD=180 K was estimated using the temperature dependence of the integral intensity of Mössbauer spectra for specified temperature range. The inequality Beff=(0.7-0.9) Bext was obtained in external field Mössbauer measurement that points to antiferromagnetically coupled Fe atoms, which have a tendency to align their spins perpendicular to Bext. Nano length scale magnetic inhomogeneities nearby and far above TC were revealed, which assumed that it is caused by mixed antiferromagnetically and ferromagnetically coupled Fe atom spins. The anti-Invar behavior of Fe-Ni-C alloy is explained in terms of evolution of magnetic order with changing temperature resulting from thermally varied interspin interaction and decreasing stiffness of interatomic bond.

  17. Algorithm for recognition and measurement position of pitches on invar scale with submicron accuracy

    Science.gov (United States)

    Lashmanov, Oleg; Korotaev, Valery

    2015-05-01

    High precision optical encoders are used for many high end computerized numerical control machines. Main requirement for such systems are accuracy and time of measurement, therefore image processing are often performed by FPGA or DSP. This article will describe image processing algorithm for detecting and measuring pitch position on invar scale, which can be easily implemented on specified target hardware. The paper proposed to use a one-dimensional approach for pitch recognition and measure its position on the image. This algorithm is well suited for implementation on FPGA and DSP and provide accuracy 0.07 pixel.

  18. Thermal expansion, elastic properties and the Moessbauer effect of stainless Invar

    International Nuclear Information System (INIS)

    Hausch, G.; Mohri, T.; Nakamura, Y.; Torok, E.

    1979-01-01

    The thermal expansion, the elastic moduli (E,G,B) and the specific heat of three Co-Fe-Cr alloys are reported together with the dependence of these properties. Alloys with FCC structure exhibit the Invar anomaly, i.e., a large spontaneous volume magnetostriction and an elastic softening below Tsub(c). Data for the spontaneous volume magnetostriction and for the ΔE-Effect are given. The Moessbauer effect was measured at 4.2, 77 K and room temperature. (Auth.)

  19. Theoretical aspects of the FecNi1-c Invar alloy

    DEFF Research Database (Denmark)

    Abrikosov, I. A.; Eriksson, O.; Söderlind, P.

    1995-01-01

    . For fcc Fe we find that several magnetic states are locally stable whereas for the FeNi alloys only one magnetic state is stable. In agremeent with previous theories for explaining the Invar effect in the Fe65Ni35 alloy, we find that at this concentration the LS and HS states are very similar in energy......We present first-principles coherent-potential-approximation calculations for the fcc FeNi alloy. We have found that this system is characterized by a competition between a low-spin (LS) and a high-spin (HS) state, and we have calculated this energy difference as a function of alloy concentration...

  20. The effect of pressure on the Curie temperature in Fe-Ni Invar mechanical alloys

    CERN Document Server

    Wei, S; Zach, R; Matsushita, M; Takahashi, A; Inoue, H; Ono, F; Maeta, H; Iwase, A; Endo, S

    2002-01-01

    Measurements of the temperature dependence of the AC susceptibility were made for Fe-Ni Invar mechanical alloys under hydrostatic pressures up to 1.5 GPa. The Curie temperatures decreased linearly with pressure. The rate of decrease became larger for specimens annealed at higher temperatures. The temperature of annealing after ball milling has been directly related to the extent of the chemical concentration fluctuation, and the extent becomes smaller for specimens annealed at higher temperature. This tendency can be explained by assuming a Gaussian distribution function.

  1. Noncollinear Spin Structure in Fe--Ni Invar Alloy Probed by Magnetic EXAFS at High Pressure

    Science.gov (United States)

    Matsumoto, Ken; Maruyama, Hiroshi; Ishimatsu, Naoki; Kawamura, Naomi; Mizumaki, Masaichiro; Irifune, Tetsuo; Sumiya, Hitoshi

    2011-02-01

    To examine theoretical models of the Invar effect, X-ray magnetic circular dichroism and magnetic extended X-ray absorption fine structure (MEXAFS) measurements are performed under high pressures at the Fe and Ni K-edges in 35.4 at. % Ni--Fe alloy. An oscillatory MEXAFS signal is observed up to 6 GPa. Its amplitude significantly decreases with increasing pressure. The magnetic component of the radial distribution function, obtained by taking the Fourier transform, shows a different reduction in the ferromagnetic correlations of Fe and Ni absorbing atoms. The present results are favorable to the noncollinear spin structure picture rather than the Fe 2γ-state model.

  2. Invar and Elinvar type amorphous Fe-Cr-B alloys with high corrosion resistance

    Science.gov (United States)

    Kikuci, M.; Fukamichi, K.; Masumoto, T.

    1987-01-01

    Amorphous (Fe(1-x)Cr(x))85B15 alloys (x = 0 to 0.15) were prepared from the melts by rapid quenching using a single roller techinque, and their Invar and Elinvar characteristics and corrosion resistance were investigated. With an increase in chromium content the Curie temperature and the saturation magnetic moment per iron atom decreased monotonically, while the crystallization temperature incresed gradually. The thermal expansion coefficient alpha around room temperature became slightly larger with increasing chromium content. Nevertheless, these amorphous alloys exhibited excellent Invar characteristics below the Curie temperature. The value of Young's modulus increased remarkably in a relatively low magnetic field and then saturated at a field of about 80 kA/m, showing a large delta E effect. Its value as well as a longitudinal linear magnetostriction became smaller with an increase in chromium content. The temperature coefficient of Young's modulus changed from postive to negative, and the temperature range showing the Elinvar characteristics became narrower with chromium content. The temperature coefficient of delay time determined from the values of alpha and e was very small. The corrosion resistance of these alloys was extremely improved by chromium addition.

  3. Anomalous magnetic moments in Fe-Pt and Fe-Pd Invar alloys under high pressure

    CERN Document Server

    Matsushita, M; Endo, S; Ishizuka, M; Kindo, K; Ono, F

    2002-01-01

    Magnetization measurements have been carried out for disordered Fe sub 7 sub 2 Pt sub 2 sub 8 , Fe sub 6 sub 6 Pd sub 3 sub 4 , and Fe sub 6 sub 8 Pd sub 3 sub 2 Invar alloys under high pressure using a technique combining a pressure-clamp-type Drickamer cell and a pulse magnet. In Fe sub 7 sub 2 Pt sub 2 sub 8 at room temperature, the magnetization decreased rapidly with increasing pressure up to 2.5 GPa, but above 2.5 GPa the rate of decrease became small and remained at a small value up to 5.6 GPa. In Fe-Pd Invar alloys at room temperature, the magnetization decreased linearly with increasing pressure. But, at 4.2 K, the change of magnetization with pressure was small in Fe sub 6 sub 6 Pd sub 3 sub 4 , which means that Fe sub 6 sub 6 Pd sub 3 sub 4 behaves as a strong ferromagnet.

  4. Wear Resistance Improvement of Small Dimension Invar Massive Molds for CFRP Components

    Science.gov (United States)

    Giolli, C.; Turbil, M.; Rizzi, G.; Rosso, M.; Scrivani, A.

    2009-12-01

    Invar alloy (Fe-36%Ni) is used in industrial applications that require high dimensional stability because of its exceptionally low thermal expansion coefficient. The purpose of this work is to improve the wear resistance of the molds in the production of carbon-fiber reinforced plastic (CFRP) components applying thermal spray coatings. Four different kinds of commercial powders were coated on an Invar substrate: ZrO2-8Y2O3, Al2O3-13TiO2, and Cr2O3 by air plasma spray (APS) and WC-CoCr by high-velocity oxygen fuel (HVOF). Metallographic microscopy observation and scanning electron microscopic analysis were carried out, microhardness and fracture toughness were evaluated using the microindentation method. Friction behavior and wear resistance were evaluated with pin-on-disk apparatus. Tungsten carbide coating had the lowest average coefficient of friction. Cermet and alumina-titania coatings showed the lowest wear mass loss. Among the APS ceramic coatings, alumina-titania exhibited the best wear behavior and the HVOF cermet coating exhibited the best behavior among all the coatings.

  5. Spin-wave dynamics in Invar Fe65Ni35 studied by small-angle polarized neutron scattering

    NARCIS (Netherlands)

    Brück, E.H.; Grigoriev, S.V.; Deriglazov, V.V.; Okorokov, A.I.; Dijk van, N.H.; Klaasse, J.C.P.

    2002-01-01

    Abstract. Spin dynamics in Fe65Ni35 Invar alloy has been studied by left-right asymmetry of small-angle polarized neutron scattering below TC=485 K in external magnetic fields of H=0.05-0.25 T inclined relative to the incident beam. The spin-wave stiffness D and the damping & were obtained by

  6. Mössbauer studies of the states of Fe atoms in the antiferromagnetic Fe–Mn Invar alloys

    Energy Technology Data Exchange (ETDEWEB)

    Delyagin, N.N., E-mail: delyagin@srd.sinp.msu.ru; Erzinkyan, A.L.; Parfenova, V.P.; Rozantsev, I.N.

    2013-10-05

    Highlights: •The component of HFD having anomalous large value of isomer shift were identified. •The temperature dependence of the isomer shifts for LF component was observed. •We argue that the observed behavior of the isomer shift due to a local volume effect. •The observed peculiarities strongly correlate to the Invar properties of the alloys. -- Abstract: A study of the magnetic hyperfine field distribution (HFD) for {sup 57}Fe in the antiferromagnetic Fe–Mn Invar alloys have been performed by Mössbauer spectroscopy technique. The component of HFD having anomalous large value of isomer shift was observed. The component is localized in the low-field part of HFD and its intensity is equal to 12(3)%. We argue that the observed anomalous isomer shift value due to a local volume effect. The observation of the pronounced temperature dependence of the isomer shift for the low-field component strongly supports a relationship between the appearance of the component and the Invar effect. Analogous features were found previously in the Fe–Ni and Fe–Al Invar alloys. On the basis of the results, we have reason to believe that the existence of the Fe sites having anomalous isomer shift values (and, as we suggest, the anomalous large local volume) is a common characteristic for Fe-based Invar alloys with the competing exchange interactions. In such systems, the radial dependences of the competing exchange interactions are the key factors in the determination of the ground-state properties of the different atomic configurations.

  7. The Numerical and Experimental Investigation of the Multi-layer Laser-MIG Hybrid Welding for Fe36Ni Invar Alloy

    Science.gov (United States)

    Zhan, Xiaohong; Liu, Yun; Ou, Wenmin; Gu, Cheng; Wei, Yanhong

    2015-12-01

    Numerical and experimental investigations of multi-layer laser-MIG hybrid welding for Fe36Ni Invar alloy were presented in this paper. The multi-layer laser-MIG hybrid welding experiments with different parameters were conducted for the 19.5-mm-thick Invar plates. A finite element (FE) model was established to predict the temperature field, residual stress, and deformation distribution during and after welding. A plane-conical combined heat source model was used to simulate the laser-MIG hybrid welding process. Different numbers of welding layers were chosen to study the effect of welding layer on the temperature field, residual stress, and deformation distribution. It was found that the maximum residual stress of Invar plates after laser-MIG hybrid welding is 300 MPa and maximum deformation is 0.4 mm, so that laser-MIG hybrid welding can be used in actual manufacture of Invar moulds.

  8. Spin-lattice interactions studied by polarised and unpolarised inelastic scattering application to the invar problem

    Energy Technology Data Exchange (ETDEWEB)

    Brown, P.J. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)

    1996-11-01

    A semi-quantitative analysis is given of some of the ways in which spin-lattice interactions can modify the cross-sections observable in neutron scattering experiments. This analysis is applied to the scattering from the invar alloy Fe{sub 65}Ni{sub 35} using a model in which the magnetic moment is a function of the near neighbour separation. This model has been applied to clarify the results of inelastic scattering experiments carried out on Fe{sub 65}Ni{sub 35} using both polarised and unpolarised neutrons. The extra information obtainable using polarised neutrons as well as the difficulties and limitations of the technique for inelastic scattering are discussed. (author) 8 figs., 14 refs.

  9. Critical magnetic scattering in invar Fe sub 6 sub 5 Ni sub 3 sub 5 alloy

    CERN Document Server

    Grigoriev, S V; Okorokov, A I; Eckerlebe, H; Kozik, G

    2002-01-01

    A critical small angle polarized neutron scattering experiment on invar Fe sub 6 sub 5 Ni sub 3 sub 5 alloy was performed in the magnetic field H of value from 10 to 1000 G using a special 'inclined' geometry (H is inclined to the wave vector k). Two contributions to the critical scattering were studied in the temperature range T sub C+-0.1T sub C : first, the two-spin correlation function with its amplitude and the correlation length R sub C (T,H) and, second, the three-spin dynamical spin-correlation function, by extracting an asymmetric part of the polarization-dependent scattering. The data are interpreted in terms of static and dynamic scaling theory. (orig.)

  10. Pressure-Induced Invar Behavior in Pd[subscript 3]Fe

    Energy Technology Data Exchange (ETDEWEB)

    Winterrose, M.L.; Lucas, M.S.; Yue, A.F.; Halevy, I.; Mauger, L.; Muñoz, J.A.; Hu, Jingzhu; Lerche, M.; Fultz, B.; (CIT); (CIW); (UC)

    2009-06-17

    Synchrotron x-ray diffraction (XRD) measurements, nuclear forward scattering (NFS) measurements, and density functional theory (DFT) calculations were performed on L1{sub 2}-ordered Pd{sub 3}Fe. Measurements were performed at 300 K at pressures up to 33 GPa, and at 7 GPa at temperatures up to 650 K. The NFS revealed a collapse of the Fe57 magnetic moment between 8.9 and 12.3 GPa at 300 K, coinciding with a transition in bulk modulus found by XRD. Heating the sample under a pressure of 7 GPa showed negligible thermal expansion from 300 to 523 K, demonstrating Invar behavior. Zero-temperature DFT calculations identified a ferromagnetic ground state and showed several antiferromagnetic states had comparable energies at pressures above 20 GPa.

  11. Anharmonicity and Quantum Effects in Thermal Expansion of an Invar Alloy

    Science.gov (United States)

    Yokoyama, Toshihiko; Eguchi, Keitaro

    2011-08-01

    We have investigated the anharmonicity and quantum effects in the Invar alloy Fe64.6Ni35.4 that shows anomalously small thermal expansion. We have performed Fe and Ni K-edge extended x-ray-absorption fine-structure spectroscopic measurements and the computational simulations based on the path-integral effective-classical-potential theory. The first nearest-neighbor (NN) shells around Fe show almost no thermal expansion, while those around Ni exhibit meaningful but smaller expansion than that of fcc Ni. At low temperature, the quantum effect is found to play an essentially important role, which is confirmed by comparing the quantum-mechanical simulations to the classical ones. The anharmonicity (asymmetric distribution) clearly exists for all the first NN shells as in normal thermal expansion systems, implying the breakdown of the direct correspondence between thermal expansion and anharmonicity.

  12. Development of new methods for studying the decomposition in aging invars

    Science.gov (United States)

    Uvarov, A. I.; Sandovskii, V. A.; Anufrieva, E. I.; Vil'danova, N. F.; Filippov, Yu. I.

    2014-07-01

    N30K10T3 and N28K10T3 invar alloys are studied. After water quenching from 1150°C, they consist of supersaturated solid solutions, which can decompose in aging in the temperature range 500-700°C with the precipitation of intermetallic Ni3Ti nanoparticles. It is shown that the decomposition can be controlled by measuring the magnetic (first harmonic amplitude, phase angle φ shift, magnetic susceptibility μ) and electric (electrical conductivity σ) parameters as functions of the isothermal holding time at various aging temperatures. The alloys are studied in the following three initial states: after quenching, phase transformation-induced hardening (γ → α → γpt), and cold (20°C) plastic deformation by 30%.

  13. Pressure-induced Novel Electronic State of Fe70Ni30 Invar Alloy

    Science.gov (United States)

    Oomi, Gendo; Saito, Ryohei; Ohashi, Masashi; Nakano, Tomohito

    The electrical resistance and magnetoresistance of Fe70Ni30 Invar alloy have been measured at high pressure up to 15 GPa. It is found that the coefficients of T2 term in the electrical resistance increases with increasing pressure but tends to saturate above 12 GPa suggesting a peak above 15 GPa, which implies a pressure-induced quantum phase transition. We found for the first time that the magnetoresistance at 4.2 K is negative below 11 GPa but becomes positive above 12 GPa. This corresponds to a crossover in the electronic state from localized moment regime to a paramagnetic or new magnetic state. The origins will be discussed briefly in connection with the recent experimental results and theoretical calculation.

  14. Microstructures responsible for the invar and permalloy effects in Fe-Ni alloys

    Science.gov (United States)

    Ustinovshchikov, Yu. I.; Shabanova, I. N.; Lomova, N. V.

    2015-05-01

    The experimental studies of Fe68Ni32 and Fe23Ni77 alloys by transmission electron microscopy and X-ray electron spectroscopy show that the ordering-separation phase transition in these alloys occurs in a temperature range near 600°C. At temperatures higher than the transition temperature, the ordering energy of the alloy is positive, and the structures contain clusters enriched in one of the components. After heat treatment at the temperatures where the invar effect in the Fe68Ni32 alloy is maximal, a modulated microstructure forms. Below the transition temperature, the ordering energy is negative, which provides a tendency to formation of chemical compounds. After aging at these temperatures (where the Fe23Ni77 alloy exhibits high permalloy properties), highly dispersed completely coherent particles of the FeNi3 phase with structure L12 precipitate in a solid solution.

  15. Radiation-induced separation of solid solution in Fe-Ni invar

    Science.gov (United States)

    Danilov, S. E.; Arbuzov, V. L.; Kazantsev, V. A.

    2011-07-01

    Radiation-induced solid solution separation (RISSS) in the Fe-34.7 at.% Ni invar alloy was investigated by residual resistivity and linear thermal expansion coefficient (TEC) measurements. The alloy was irradiated with 5 MeV electrons at 245-570 K and isochronous annealed. It was found that RISSS leads to an increase of 20% in the residual resistivity and an increase of 10 -5 K -1 in the TEC for an electron irradiation dose of 5 × 10 18 cm -2. The kinetics of RISSS are the same, but the irradiation efficiency coefficient increases approximately by a factor of 10 when the irradiation temperature rises in the range of 240-570 K. Vacancy clusters, which are formed under irradiation, retard the decomposition. It was shown that dissociation of the vacancy clusters at temperatures of 320-500 K was followed by the free migration of the formed vacancies, and leads to further RISSS.

  16. Heat-Transfer Behavior of Mold Fluxes for Continuous Casting of Invar Alloy

    Science.gov (United States)

    Yan, Wei; Chen, Weiqing; Lippold, Carsten; Xu, Hongcheng

    2013-12-01

    The heat-transfer behavior across mold fluxes for Invar alloy Fe-36Ni would introduce significant influence on the slab surface quality. A study on the heat-transfer property of mold flux film for Invar alloy Fe-36Ni was carried out by an interaction between laboratory simulation and field trial. The study results indicate that great effect on heat transfer across flux film is caused by chemical compositions of mold fluxes. An increase of basicity and CaF2 content suppresses heat transfer across flux film; heat transfer across flux film increases when the Al2O3 content increases from 4 pct to 8 pct but decreases when Al2O3 content is above 8 pct. The crystalline phases of both the conventional mold fluxes and the improved mold fluxes are all cuspidine phases. However, crystallization capability of the improved mold fluxes decreases as the result of the increase of basicity and CaF2 content as well as the decrease of Al2O3 content. The average thickness of flux film taken from mold is about 1.6 mm, and the crystalline fraction is only 21.4 pct. All these promote heat transfer across the flux film. The field trial of the improved mold fluxes shows that the properties of liquid slag are steady during continuous casting; comprehensive heat transfer across flux film meets the needs of continuous casting of Fe-36Ni. Border solidification structures of solidified shell are refined remarkably, and hot cracking gets avoidance eventually.

  17. Magnetic EXAFS study of Fe-Ni invar alloy under high pressure using nano-polycrystalline diamond anvils

    Science.gov (United States)

    Matsumoto, Ken; Maruyama, Hiroshi; Ishimatsu, Naoki; Kawamura, Naomi; Mizumaki, Masaichiro; Irifune, Tetsuo; Sumiya, Hitoshi

    2012-07-01

    The magnetic EXAFS technique was applied to study the local magnetic structure in Fe-Ni Invar alloy under high pressures. Nano-polycrystalline diamond was used to apply pressure in a diamond anvil cell. As a result, we succeeded in recording a glitch-free spectrum with a high accuracy by preventing Bragg diffraction from the diamonds. As the pressure was increased, the ferromagnetic correlation was strongly reduced, which was more remarkable for Fe atoms than for Ni atoms. The canting effect of the magnetic moment may be crucial for a rapid decrease in the ferromagnetic correlation. This local magnetic structure in the Invar alloy is consistent with a model based on the non-collinear spin structure.

  18. A study of phase stability in invar Fe--Ni alloys obtained by non-conventional methods

    Science.gov (United States)

    Scorzelli, R. B.

    1997-09-01

    It is known that thermodynamic equilibrium in Fe--Ni alloys, in the invar composition at temperatures below 450°C, is difficult to achieve because of the slow diffusion rate at low temperatures. One of the ways in which we can study phase transformation which may be responsible for invar behavior is to investigate: (i) materials of similar composition obtained by non-conventional methods, known to allow the enhancement of diffusion at temperatures where atomic mobility is nil on the laboratory time scale; (ii) materials which have been treated for very long periods of time (geological time scale) in the same temperature range, such as in meteorites. In this context we have studied the phase stability of Fe--Ni phases in mechanically alloyed powders, in ion-beam mixed multilayers and in meteorites.

  19. Two 100 m Invar® Transfer Lines at CERN : Design Principles and Operating Experience for Helium Refrigeration

    CERN Document Server

    Claudet, S; Millet, F; Roussel, E; Sengelin, J P

    2005-01-01

    The distribution of helium for the Large Hadron Collider (LHC), at CERN, will require a large variety of transfer lines. At the time of qualification of possible technologies, Invar® was investigated as potential material for internal tubes. Intensive developments were made in industry to qualify the use of Invar® M93 and its associated welding parameters. Although all tests showed good perspective, the risk associated with the lack of proven reference turned out to be dissuasive with respect to the possible cost savings for the LHC cryogenic system. However, since DN100 transfer lines were necessary for the supply and return of a test facility over a distance of 100 m, an Invar® based solution was considered, as repair or exchange would have been less dramatic than in the LHC accelerator tunnel. After recalling the technical requirements, the required material qualification will be presented as well as the design principles and operating features. This equipment has been first cooled-down to 4.5 K and acc...

  20. Interfacial microstructure and mechanical properties of joining electroless nickel plated quartz fibers reinforced silica composite to Invar

    International Nuclear Information System (INIS)

    Lei, Zhao; Lixia, Zhang; Xiaoyu, Tian; Peng, He; Jicai, Feng

    2011-01-01

    Vacuum brazing of electroless nickel plated quartz fibers reinforced silica composite (QFSC) to Invar alloy using Ag-Cu eutectic alloy at various temperatures (1073-1163 K) and times (5-35 min) has been investigated. The scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction examination of the joints showed that the junction between QFSC and Invar produced reaction products like Cu 3.8 Ni, Cu (s, s), Ni (s, s) and Ag (s, s), with the structure of Invar/Cu 3.8 Ni + Ni (s, s)/Ni (s, s) + Cu 3.8 Ni + Ag (s, s) + Cu (s, s)/Cu (s, s) + Cu 3.8 Ni + Ni (s, s) + QFSC. The shear strength of joint was effected by the changes of relative amount of Cu-Ni eutectic structure (Cu 3.8 Ni + Ni (s, s)) and thickness of nickel plating film at different parameters. The shear strength of joint increased when there were proper amount of Cu-Ni eutectic structure and nickel plating film for reinforcement, and decreased while them were consumed excessively in interaction. The maximum shear strength of joint is 29 MPa, which was brazed at 1103 K for 15 min.

  1. Improved magnetic and electrical properties of Cu doped Fe–Ni invar alloys synthesized by chemical reduction technique

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Sajjad, E-mail: sajjadhaleli@gmail.com [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Ziya, Amer Bashir [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Ashiq, Muhammad Naeem, E-mail: naeemashiqqau@yahoo.com [Institute of Chemical Sciences, Bahauddin Zakariya University, Multan 60800 (Pakistan); Ibrahim, Ather; Atiq, Shabbar [Institute of Advanced Materials, Bahauddin Zakariya University, Multan 60800 (Pakistan); Ahmad, Naseeb [Department of Physics, Government College University, Faisalabad (Pakistan); Shakeel, Muhammad [Institute of Advanced Materials, Bahauddin Zakariya University, Multan 60800 (Pakistan); Khan, Muhammad Azhar [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan)

    2016-12-01

    Fe–Ni–Cu invar alloys of various compositions (Fe{sub 65}Ni{sub 35−x}Cu{sub x}, x=0, 0.2, 0.6, 1, 1.4 and 1.8) were synthesized via chemical reduction route. These alloys were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM) techniques. The XRD analysis revealed the formation of face centered cubic (fcc) structure. The lattice parameter and the crystallite size of the investigated alloys were calculated and the line broadening indicated the nano-crystallites size of alloy powder. The particle size was estimated from SEM and it decreases by the incorporation of Cu and found to be in the range of 24–40 nm. The addition of Cu in these alloys appreciably enhances the saturation magnetization and it increases from 99 to 123 emu/g. Electrical conductivity has been improved with Cu addition. The thermal conductivity was calculated using the Wiedemann–Franz law. - Graphical abstract: M–H loops of Fe{sub 65}Ni{sub 35−x}Cu{sub x} x =0, 0.2, 0.6, 1, 1.4, 1.8 nano-invar alloys. - Highlights: • A simple method has been employed for the synthesis of invar alloys. • The magnetic properties has been enhanced by the Cu content. • The electrical conductivity has been improved.

  2. Invar behavior of NANOPERM-type amorphous Fe-(Pt)-Zr-Nb-Cu-B alloys

    Science.gov (United States)

    Gondro, J.; Świerczek, J.; Rzącki, J.; Ciurzyńska, W.; Olszewski, J.; Zbroszczyk, J.; Błoch, K.; Osyra, M.; Łukiewska, A.

    2013-09-01

    Transmission Mössbauer spectra of amorphous Fe86Zr7Nb1Cu1B5, Fe81Zr7Nb1Cu1B10 and Fe81Pt5Zr7Nb1Cu1B5 alloys in the as-quenched state and subjected to the accumulative annealing for 15 min in the temperature range from 573 K up to 750 K are presented. After these heat treatments the alloys remain in the amorphous state. The accumulative annealing for 15 min at 573 K and then 600 K of the Fe86Zr7Nb1Cu1B5 and Fe81Zr7Nb1Cu1B10 alloys causes the narrowing of the transmission Mössbauer spectra as compared to the as-quenched state and the decrease of the average hyperfine field induction which is connected with the invar effect. For similar behavior in Fe81Pt5Zr7Nb1Cu1B5 alloy the accumulative annealing up to 700 K is needed. With further increase of the annealing temperature up to 750 K the broadening of the Mössbauer spectra and the increase of the average hyperfine field induction occur. The lowest value of the average hyperfine field induction of amorphous samples is accompanied by the lowest value of the Curie temperature. The investigated amorphous alloys do not reach the magnetic saturation up to the magnetizing field of 2 T and the coefficient in Holstein-Primakoff term is about one order in magnitude larger than in other classical FeCo-based amorphous alloys due to the non-collinear magnetic structure. The Mössbauer spectra and hysteresis loops of the amorphous Fe86Zr7Nb1Cu1B5 alloy in the as-quenched state and after the accumulative annealing at 573+620 K for 15 min are sensitive to the tensile stresses subjected to the sample. Such behavior is ascribed to the invar anomalies.

  3. "Invar"-like behavior in compressed Fe7C3 with implication for deep carbon cycle

    Science.gov (United States)

    Liu, J.; Li, J.; Ikuta, D.

    2014-12-01

    Iron carbide Fe7C3 has recently emerged as a leading candidate component of the inner core because it is likely the first phase to solidify from a liquid containing iron and a small amount of carbon, and previous studies suggest that it provides a good match for the density of the inner core under relevant conditions. Pressure-induced magnetic transitions have been observed in Fe7C3 (Chen et al., 2012). The pressure of the ferromagnetic to paramagnetic transition remains controversial and its effect on equation of state (EoS) is unclear, thus introducing uncertainties in estimating the density of Fe7C3 under inner core pressures. Here we report the lattice parameters and unit cell volume of hexagonal Fe7C3 at 300 K and up to 70 GPa, obtained through synchrotron x-ray diffraction measurements using a diamond anvil cell. The experiments used fine powder of Fe7C3 that was synthesized in the multi-anvil apparatus at the University of Michigan. The sample was embedded in neon pressure medium together with Au powder and ruby spheres as additional pressure markers. We observed significant softening at 5~8 GPa, similar to the reported "invar"-like behavior in Fe-Ni alloy (Dubrovinsky et al., 2001). For comparison, the compression curve of iron in the same loading turned out to be smooth as expected, which confirms that the abnormal behavior in Fe7C3 compression curve is due to its own property change and not an artifact. The new data allow us to establish the equation-of-state (EoS) of Fe7C3 and then estimate the density of Fe7C3 at inner core conditions. References: Chen, B., Gao, L.L., Lavina, B., Dera, P., Alp, E.E., Zhao, J.Y., Li, J., 2012. Magneto-elastic coupling in compressed Fe7C3 supports carbon in Earth's inner core. Geophys Res Lett 39. Dubrovinsky, L., Dubrovinskaia, N., Abrikosov, I.A., Vennstrom, M., Westman, F., Carlson, S., van Schilfgaarde, M., Johansson, B., 2001. Pressure-induced invar effect in Fe-Ni alloys. Phys Rev Lett 86, 4851-4854.

  4. Effects of energetic ion irradiation on the magnetism of Fe-Ni Invar alloy

    Science.gov (United States)

    Matsushita, M.; Akamatsu, S.; Matsushima, Y.; Iwase, A.

    2013-11-01

    The magnetic properties of Fe-Ni Invar alloys are significantly affected by ion irradiation. Au3+ with the energy of 16 MeV irradiation effects on the magnetism of Fe66Ni34 have been reported in this paper. Considering from the temperature variations of AC susceptibility of irradiated Fe66Ni34, Curie temperature of a part of sample increase with increasing incident ion fluence, and the magnetization of irradiated Fe66Ni34 is also increase. The FCC structure of Fe66Ni34 is not changed by ion irradiation; however peaks become broader with increasing ion fluence. It means that lattice fluctuations are generated owing to ion irradiation. However it cannot be considered that lattice fluctuations observed X-ray diffraction measurements are enough to increase the Curie temperature observed in AC susceptibility measurements. Then, we suggest as the considerable origin of increasing TC, atomic mixing effects owing to the ion irradiation. It might change the chemical ordering reported in the diffused scattering, such as Fe-Fe coupling.

  5. Low temperature study of mechanically alloyed Fe67.5Ni32.5 Invar sample

    Science.gov (United States)

    Valenzuela, J. L.; Valderruten, J. F.; Pérez Alcázar, G. A.; Colorado, H. D.; Romero, J. J.; González, J. M.; Greneche, J. M.; Marco, J. F.

    2015-07-01

    The study at low temperatures of powder of the Invar alloy, Fe67.5Ni32.5, produced by mechanical alloying, shows that the sample presents two structural phases, the Fe-Ni BCC and the Fe-Ni FCC. The 57Fe Mössbauer spectra obtained in this sample at different temperatures were fitted considering two hyperfine magnetic field distributions. The first one having the larger mean field and only one peak (at ca. 35 T, varying with T), is associated with the BCC phase, and the second one, presenting several broad peaks (distributed between 10 and 35 T), is associated to the FCC phase. A singlet, which is associated to low spin Fe sites of the FCC phase, was also considered. The mean hyperfine magnetic field of the BCC phase increases monotonically as temperature decreases, while that of the FCC phase presents an anomaly near 75 K. The real part of the ac magnetic susceptibility temperature scans presents a peak whose position increases from 31 to 39 K, when the ac field frequency increases from 100 to 5000 Hz. These results permit to associate the detected anomaly to the occurrence of a reentrant spin glass transition.

  6. Radiation-induced separation of solid solution in Fe-Ni invar

    Energy Technology Data Exchange (ETDEWEB)

    Danilov, S.E., E-mail: danilov@imp.uran.ru [Institute of Metal Physics, Russian Academy of Sciences, Ural Branch (Russian Federation); Arbuzov, V.L.; Kazantsev, V.A. [Institute of Metal Physics, Russian Academy of Sciences, Ural Branch (Russian Federation)

    2011-07-15

    Radiation-induced solid solution separation (RISSS) in the Fe-34.7 at.% Ni invar alloy was investigated by residual resistivity and linear thermal expansion coefficient (TEC) measurements. The alloy was irradiated with 5 MeV electrons at 245-570 K and isochronous annealed. It was found that RISSS leads to an increase of 20% in the residual resistivity and an increase of 10{sup -5} K{sup -1} in the TEC for an electron irradiation dose of 5 x 10{sup 18} cm{sup -2}. The kinetics of RISSS are the same, but the irradiation efficiency coefficient increases approximately by a factor of 10 when the irradiation temperature rises in the range of 240-570 K. Vacancy clusters, which are formed under irradiation, retard the decomposition. It was shown that dissociation of the vacancy clusters at temperatures of 320-500 K was followed by the free migration of the formed vacancies, and leads to further RISSS.

  7. Low temperature study of mechanically alloyed Fe{sub 67.5}Ni{sub 32.5} Invar sample

    Energy Technology Data Exchange (ETDEWEB)

    Valenzuela, J.L. [Departamento de Física, Universidad del Valle, A. A. 25360, Cali (Colombia); Valderruten, J.F. [Departamento de Ingeniería, Universidad Cooperativa de Colombia, Bucaramanga (Colombia); Pérez Alcázar, G.A., E-mail: gpgeperez@gmail.com [Departamento de Física, Universidad del Valle, A. A. 25360, Cali (Colombia); Colorado, H.D. [Departamento de Física, Universidad del Valle, A. A. 25360, Cali (Colombia); Romero, J.J. [Instituto de Microelectrónica de Madrid, CNM, CSIC, C/Isaac Newton 8, Tres Cantos, 28760 Madrid (Spain); González, J.M. [Unidad Asociada ICMM-IMA, Apdo. 155, Las Rozas, 28230 Madrid (Spain); Greneche, J.M. [LUNAM, Université du Maine, Institut des Molécules et Matériaux du Mans, UMR CNRS 6283, 72085 Le Mans, Cedex 9 (France); Marco, J.F. [Instituto de Química-Física ' ' Rocasolano' ' , CSIC, C/Serrano 119, 28006 Madrid (Spain)

    2015-07-01

    The study at low temperatures of powder of the Invar alloy, Fe{sub 67.5}Ni{sub 32.5}, produced by mechanical alloying, shows that the sample presents two structural phases, the Fe–Ni BCC and the Fe–Ni FCC. The {sup 57}Fe Mössbauer spectra obtained in this sample at different temperatures were fitted considering two hyperfine magnetic field distributions. The first one having the larger mean field and only one peak (at ca. 35 T, varying with T), is associated with the BCC phase, and the second one, presenting several broad peaks (distributed between 10 and 35 T), is associated to the FCC phase. A singlet, which is associated to low spin Fe sites of the FCC phase, was also considered. The mean hyperfine magnetic field of the BCC phase increases monotonically as temperature decreases, while that of the FCC phase presents an anomaly near 75 K. The real part of the ac magnetic susceptibility temperature scans presents a peak whose position increases from 31 to 39 K, when the ac field frequency increases from 100 to 5000 Hz. These results permit to associate the detected anomaly to the occurrence of a reentrant spin glass transition. - Highlights: • XRD detect the BCC and FCC nanocrystalline phases in the Invar Fe{sub 67.5}Si{sub 32.5}. • Mössbauer spectra were fitted with two HMFDs and a singlet. • The MHMF and the isomer shift of the FCC structure present a kink near 61 K. • Magnetic susceptibility proved that this anomaly corresponds to a RSG- F transition. • The Invar composition of the MA Fe{sub 67.5}Si{sub 32.5} alloy presents the frustration phenomena.

  8. Stacking-fault energy and anti-Invar effect in Fe-Mn alloy from first principles

    Science.gov (United States)

    Reyes-Huamantinco, Andrei; Puschnig, Peter; Ambrosch-Draxl, Claudia; Peil, Oleg E.; Ruban, Andrei V.

    2012-08-01

    Based on state-of-the-art density-functional-theory methods we calculate the stacking-fault energy of the prototypical high-Mn steel Fe-22.5 at% Mn between 300 and 800 K. We estimate magnetic thermal excitations by considering longitudinal spin fluctuations. Our results demonstrate that the interplay between the magnetic excitations and the thermal lattice expansion is the main factor determining the anti-Invar effect, the hcp-fcc transformation temperature, and the stacking-fault energy, all of which are in good agreement with measurements.

  9. Large negative magnetic contribution to the thermal expansion in iron-platinum alloys: quantitative theory of the Invar effect.

    Science.gov (United States)

    Khmelevskyi, S; Turek, I; Mohn, P

    2003-07-18

    We show that the large negative magnetic contribution to the thermal expansion in disordered Fe-Pt alloys can be understood within the disordered local moment (DLM) approach. On the basis of first principles calculations we quantitatively describe the spontaneous volume magnetostriction for various Pt concentrations. It is found that the Invar effect in these alloys is entirely related to the state of thermal magnetic disorder modeled by the DLM states. We also show that the experimentally observed anomaly in the temperature dependence of the magnetization is due to a spontaneous reduction of the local magnetic moments rather than to "hidden excitations."

  10. Invar behavior of NANOPERM-type amorphous Fe–(Pt)–Zr–Nb–Cu–B alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gondro, J.; Świerczek, J., E-mail: swiercz@wip.pcz.pl; Rzącki, J.; Ciurzyńska, W.; Olszewski, J.; Zbroszczyk, J.; Błoch, K.; Osyra, M.; Łukiewska, A.

    2013-09-15

    Transmission Mössbauer spectra of amorphous Fe{sub 86}Zr{sub 7}Nb{sub 1}Cu{sub 1}B{sub 5}, Fe{sub 81}Zr{sub 7}Nb{sub 1}Cu{sub 1}B{sub 10} and Fe{sub 81}Pt{sub 5}Zr{sub 7}Nb{sub 1}Cu{sub 1}B{sub 5} alloys in the as-quenched state and subjected to the accumulative annealing for 15 min in the temperature range from 573 K up to 750 K are presented. After these heat treatments the alloys remain in the amorphous state. The accumulative annealing for 15 min at 573 K and then 600 K of the Fe{sub 86}Zr{sub 7}Nb{sub 1}Cu{sub 1}B{sub 5} and Fe{sub 81}Zr{sub 7}Nb{sub 1}Cu{sub 1}B{sub 10} alloys causes the narrowing of the transmission Mössbauer spectra as compared to the as-quenched state and the decrease of the average hyperfine field induction which is connected with the invar effect. For similar behavior in Fe{sub 81}Pt{sub 5}Zr{sub 7}Nb{sub 1}Cu{sub 1}B{sub 5} alloy the accumulative annealing up to 700 K is needed. With further increase of the annealing temperature up to 750 K the broadening of the Mössbauer spectra and the increase of the average hyperfine field induction occur. The lowest value of the average hyperfine field induction of amorphous samples is accompanied by the lowest value of the Curie temperature. The investigated amorphous alloys do not reach the magnetic saturation up to the magnetizing field of 2 T and the coefficient in Holstein–Primakoff term is about one order in magnitude larger than in other classical FeCo-based amorphous alloys due to the non-collinear magnetic structure. The Mössbauer spectra and hysteresis loops of the amorphous Fe{sub 86}Zr{sub 7}Nb{sub 1}Cu{sub 1}B{sub 5} alloy in the as-quenched state and after the accumulative annealing at 573+620 K for 15 min are sensitive to the tensile stresses subjected to the sample. Such behavior is ascribed to the invar anomalies. - Highlights: • Complex magnetic transformations found in the amorphous Fe{sub 86}Zr{sub 7}Nb{sub 1}Cu{sub 1}B{sub 5}, Fe{sub 81}Zr{sub 7}Nb{sub 1}Cu{sub 1}B

  11. Research on the microstructure and properties of laser-MIG hybrid welded joint of Invar alloy

    Science.gov (United States)

    Zhan, Xiaohong; Zhang, Dan; Wei, Yanhong; Wang, Yuhua

    2017-12-01

    In order to solve the problem of large deformation, low production efficiency and high tendency of hot cracking in welding 19.05 mm thick plates of Fe36Ni Invar alloy, laser-MIG hybrid multi-layer welding technique (LMHMW) has been developed. To investigate the influence of different welding parameters on the joint properties, optical microscope observation, SEM, EDS and microhardness measurement were conducted. Experimental results illustrated that different matching of welding parameters significantly affected the depth-to-width ratio, formation of defects and HAZ width. Besides, weld zone were consisted of two regions according to the different grain shape. The region near center of weld seam (region 1) was columnar dendrite induced by laser, while the region far away from weld seam center (region 2) was cellular dendrite which was mainly caused by MIG arc. The peak value of microhardness appeared at the center of weld seam since the grains in region 1 were relatively fine, and the lowest hardness value was obtained in HAZ. In addition, results showed that the sheets can be welded at optimum process parameters, with few defects such as, surface oxidation, porosity, cracks and lack of penetration in the welding seam: laser power of backing weld P = 5500 W, welding current I = 240 A, welding speed v = 1 m/min. laser power of filling weld P = 2000 W, welding current I = 220 A, welding speed v = 0.35 m/min. laser power of cosmetic weld P = 2000 W, welding current I = 300 A, welding speed v = 0.35 m/min.

  12. Effects of energetic ion irradiation on the magnetism of Fe–Ni Invar alloy

    Energy Technology Data Exchange (ETDEWEB)

    Matsushita, M., E-mail: matsushita@eng.ehime-u.ac.jp [Graduate School of Science and Engineering, Ehime University, 3-Bunkyocho, Matsuyama (Japan); Akamatsu, S. [Graduate School of Science and Engineering, Ehime University, 3-Bunkyocho, Matsuyama (Japan); Matsushima, Y. [Graduate School of Natural Science and Technology, Okayama University, Tsushima-naka Kitaku, Okayama (Japan); Iwase, A. [Department of Materials Science, Osaka Prefecture University, Gakuencho, Sakai (Japan)

    2013-11-01

    Highlights: •16-MeV Au{sup 3+} ions were irradiated to Fe{sub 66}Ni{sub 34} alloy. •Magnetic properties of Fe{sub 66}Ni{sub 34} were changed by the irradiation. •T{sub c} of a part of sample increases due to the irradiation. •FCC structure is stable before and after irradiation. -- Abstract: The magnetic properties of Fe–Ni Invar alloys are significantly affected by ion irradiation. Au{sup 3+} with the energy of 16 MeV irradiation effects on the magnetism of Fe{sub 66}Ni{sub 34} have been reported in this paper. Considering from the temperature variations of AC susceptibility of irradiated Fe{sub 66}Ni{sub 34}, Curie temperature of a part of sample increase with increasing incident ion fluence, and the magnetization of irradiated Fe{sub 66}Ni{sub 34} is also increase. The FCC structure of Fe{sub 66}Ni{sub 34} is not changed by ion irradiation; however peaks become broader with increasing ion fluence. It means that lattice fluctuations are generated owing to ion irradiation. However it cannot be considered that lattice fluctuations observed X-ray diffraction measurements are enough to increase the Curie temperature observed in AC susceptibility measurements. Then, we suggest as the considerable origin of increasing T{sub C}, atomic mixing effects owing to the ion irradiation. It might change the chemical ordering reported in the diffused scattering, such as Fe–Fe coupling.

  13. A study of microstructures responsible for the emergence of the invar and permalloy effects in Fe–Ni alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ustinovshikov, Y., E-mail: ust@ftiudm.ru; Shabanova, I.

    2013-11-25

    Highlights: •Phase transition ‘ordering-phase separation’ occurs in Fe–Ni alloys at about 600 °C. •A modulated structure is the main reason of the invar properties of Fe–Ni alloys. •A two-phase fully coherent γ + L1{sub 2} structure is the main cause of permalloy properties. -- Abstract: The paper presents experimental results obtained by transmission electron microscopy and X-ray photoelectron spectroscopy on the Fe{sub 68}Ni{sub 32} and Fe{sub 23}Ni{sub 77} alloys, which indicate that in these alloys, the phase transition ordering-phase separation occurs in the temperature range near 600 °C. Above the transition temperature, the sign of the ordering energy is positive; clusters enriched in atoms of one of the components are observed in the structure of the alloys. A modulated microstructure is formed after heat treatment at temperatures, at which the invar effect in the Fe{sub 68}Ni{sub 32} alloy is the maximum. Below the transition temperature, the sign of the ordering energy is negative, which determines a tendency to form chemical compounds. After aging at these temperatures, when the Fe{sub 23}Ni{sub 77} alloy has high permalloy properties, highly-dispersed fully coherent particles of the L1{sub 2} (γ′) phase are found to precipitate in the solid solution.

  14. Stacking-fault energy and anti-Invar effect in FeMn alloys at high temperature

    Science.gov (United States)

    Reyes-Huamantinco, Andrei; Puschnig, Peter; Ambrosch-Draxl, Claudia; Peil, Oleg; Ruban, Andrei

    2012-02-01

    High-Mn steels (20-30at%Mn, 2-4wt%Si and Al) are of interest for the automotive industry due to their outstanding mechanical properties. Their deformation behavior has been empirically correlated to the stacking-fault energy (SFE), an important quantity in steel design that can be calculated ab-initio. Using state-of-the-art methods within density-functional theory together with Monte Carlo simulations, we calculate the free energy of the Fe-22.5at%Mn binary alloy between 300-800 K. Experimentally, the alloy is completely random and in the paramagnetic state, which we model via the coherent potential approximation and the disordered local moment approach, respectively. We treat magnetic excitations by including longitudinal spin-fluctuations and find that the FeMn alloy is an itinerant paramagnet. Our calculations confirm the experimentally observed strong magneto-volume coupling, realized in the anti-Invar behavior. We then obtain the structural stability and the SFE from free energy differences and find very good agreement with measurements. Our results demonstrate that the interplay between magnetic excitations and the thermal lattice expansion is the main factor determining the anti-Invar effect, the fcc-hcp martensitic transformation temperature and the SFE.

  15. Analysis of Formation and Interfacial WC Dissolution Behavior of WC-Co/Invar Laser-TIG Welded Joints

    Science.gov (United States)

    Xu, P. Q.; Ren, J. W.; Zhang, P. L.; Gong, H. Y.; Yang, S. L.

    2013-02-01

    During the valve fabrication, hard metal is welded to stainless steel or invar alloy for sealing purposes because of its good heat resistance operating at 500 °C. However, WC (tungsten carbide) dissolution in weld pool softens the hard metal and decreases mechanical properties near the hard metal/weld interface. In order to analyze the WC dissolution in welded joint, joining of hard metal and invar alloy was carried out using laser-tungsten inert gas hybrid welding method. Microstructures of the weld region, chemical composition were investigated using optical microscope, scanning electron microscopy, and EDAX, respectively. Mechanical properties such as microhardness and four-point bend strength test were performed. Larger and smaller WC dissolution and WC dissolution through transition layer based on thermo-dynamics were discussed. The results thus indicate that WC dissolution led to cellular microstructure, columnar crystal, and transition layer under the effect of laser beam and tungsten arc. WC dissolution was affected by metal ions Fe+, Ni+, Co+ exchange in W-M-C system, and WC grain growth was driven by forces caused by laser beam and tungsten arc in larger WC, smaller WC, and liquid Fe, Ni systems.

  16. Analysis of the current density characteristics in through-mask electrochemical micromachining (TMEMM for fabrication of micro-hole arrays on invar alloy film

    Directory of Open Access Journals (Sweden)

    Da-som JIN

    2017-06-01

    Full Text Available Invar alloy consisting of 64% iron and 36% nickel has been widely used for the production of shadow masks for organic light emitting diodes (OLEDs because of its low thermal expansion coefficient (1.86 × 10−6 cm/°C. To fabricate micro-hole arrays on 30 μm invar alloy film, through-mask electrochemical micromachining (TMEMM was developed and combined with a portion of the photolithography etching process. For precise hole shapes, patterned photoresist (PR film was applied as an insulating mask. To investigate the relationship between the current density and the material removal rate, the principle of the electrochemical machining was studied with a focus on the equation. The finite element method (FEM was used to verify the influence of each parameter on the current density on the invar alloy film surface. The parameters considered were the thickness of the PR mask, inter-electrode gap (IEG, and electrolyte concentration. Design of experiments (DOE was used to figure out the contribution of each parameter. A simulation was conducted with varying parameters to figure out their relationships with the current density. Optimization was conducted to select the suitable conditions. An experiment was carried out to verify the simulation results. It was possible to fabricate micro-hole arrays on invar alloy film using TMEMM, which is a promising method that can be applied to fabrications of OLEDs shadow masks.

  17. Direct measurement of magnetization isotherms of Fe.sub.64./sub.Ni.sub.64./sub. Invar alloy in a diamond anvil cell

    Czech Academy of Sciences Publication Activity Database

    Kamarád, Jiří; Míšek, Martin; Arnold, Zdeněk

    2014-01-01

    Roč. 34, č. 4 (2014), s. 365-370 ISSN 0895-7959 R&D Projects: GA ČR GAP204/12/0692 Institutional support: RVO:68378271 Keywords : Invar * magnetization * DAC * pressure Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.951, year: 2014

  18. Mössbauer study of local environment effects in the ordered Fe 70Al 30 Invar alloy: Temperature dependence of isomer shift in the spin-glass phase

    Science.gov (United States)

    Delyagin, N. N.; Erzinkyan, A. L.; Parfenova, V. P.; Rozantsev, I. N.

    2011-12-01

    The systematic studies of the magnetic hyperfine field distribution for 57Fe in the spin-glass (SG) phase of the ordered Fe70Al30 Invar alloy have been performed using Mössbauer spectroscopy technique in the temperature range from 5 to 80 K. Particular emphasis has been placed on the low-field component of the distribution, which is considered as corresponding to the Fe sites in the SG magnetic configurations. The main result is the observation of the pronounced temperature dependence of isomer shift for several atomic SG configurations. The temperature behavior of the local electron density is strongly correlated to the Invar properties of the Fe70Al30 alloy. We argue that the observed temperature dependence of the isomer shift due to a local volume effect. The temperature range, for which the pronounced decrease in atomic volume is observed, coincides with the range of the existence of the Invar effect. The influence of the competition between opposite in sign exchange interactions on the Invar properties is discussed.

  19. Sodium Borohydride Reduction of Aqueous Silver-Iron-Nickel Solutions: a Chemical Route to Synthesis of Low Thermal Expansion-High Conductivity Ag-Invar Alloys

    Science.gov (United States)

    Sterling, E. A.; Stolk, J.; Hafford, L.; Gross, M.

    2009-07-01

    Thermal management is a critical concern in the design and performance of electronics systems. If heat extraction and thermal expansion are not properly addressed, the thermal mismatch among dissimilar materials may give rise to high thermal stresses or interfacial shear strains, and ultimately to premature system failure. In this article, we present a chemical synthesis process that yields Ag-Invar (64Fe-36Ni) alloys with a range of attractive properties for thermal management applications. Sodium borohydride reduction of an aqueous Ag-Fe-Ni metal salt solution produces nanocrystalline powders, and conventional powder processing converts this powder to fine-grained alloys. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy, thermomechanical analysis, and electrical conductivity measurements; thermal conductivity is estimated using the Wiedemann-Franz law. Sintering of Ag-Fe-Ni powders leads to the formation of two-phase silver-Invar alloys with low coefficients of thermal expansion (CTEs) and relatively high electrical conductivities. A sample of 50Ag-50Invar exhibits a CTE of 8.76 μm/(m· °C) and an estimated thermal conductivity of 236 W/(m·K). The Ag-Invar alloys offer thermodynamic stability and tailorable properties, and they may help address the need for improved packaging materials.

  20. Moessbauer study of local environment effects in the ordered Fe{sub 70}Al{sub 30} Invar alloy: Temperature dependence of isomer shift in the spin-glass phase

    Energy Technology Data Exchange (ETDEWEB)

    Delyagin, N.N., E-mail: delyagin@srd.sinp.msu.ru [Institute of Nuclear Physics, Moscow State University, 119991 Moscow (Russian Federation); Erzinkyan, A.L.; Parfenova, V.P.; Rozantsev, I.N. [Institute of Nuclear Physics, Moscow State University, 119991 Moscow (Russian Federation)

    2011-12-15

    The systematic studies of the magnetic hyperfine field distribution for {sup 57}Fe in the spin-glass (SG) phase of the ordered Fe{sub 70}Al{sub 30} Invar alloy have been performed using Moessbauer spectroscopy technique in the temperature range from 5 to 80 K. Particular emphasis has been placed on the low-field component of the distribution, which is considered as corresponding to the Fe sites in the SG magnetic configurations. The main result is the observation of the pronounced temperature dependence of isomer shift for several atomic SG configurations. The temperature behavior of the local electron density is strongly correlated to the Invar properties of the Fe{sub 70}Al{sub 30} alloy. We argue that the observed temperature dependence of the isomer shift due to a local volume effect. The temperature range, for which the pronounced decrease in atomic volume is observed, coincides with the range of the existence of the Invar effect. The influence of the competition between opposite in sign exchange interactions on the Invar properties is discussed. - Highlights: > Spin-glass phase of the ordered Fe{sub 70}Al{sub 30} Invar alloy has been investigated using Moessbauer spectroscopy technique. > Main result is the observation of the pronounced temperature dependence of isomer shifts for several atomic configurations. > Observed temperature dependencies due to a local volume effect. > Temperature variations of the isomer shifts are strongly correlated to the Invar properties of the Fe{sub 70}Al{sub 30} alloys.

  1. Stress-induced Curie temperature increase in the Fe{sub 64}Ni{sub 36} invar alloy

    Energy Technology Data Exchange (ETDEWEB)

    Gorria, Pedro; Martinez-Blanco, David; Blanco, Jesus A. [Departamento de Fisica, Universidad de Oviedo (Spain); Boada, Roberto; Chaboy, Jesus [ICMA and Departamento de Fisica de la Materia Condensada, CSIC - Universidad de Zaragoza (Spain); Fernandez-Martinez, Alejandro [LGIT, University of Grenoble and CNRS, Maison des Geosciences, Grenoble (France); Institut Laue-Langevin, Grenoble (France); Garbarino, Gaston; Castro, German R.; Mezouar, Mohamed [European Synchrotron Radiation Facility (ESRF), Grenoble (France); Smith, Ronald I. [ISIS Facility, RAL, Chilton, Didcot, Oxon (United Kingdom); Alonso, J.I.G. [Department of Physical and Analytical Chemistry, University of Oviedo (Spain); Hernando, Antonio [Instituto de Magnetismo Aplicado, UCM-ADIF-CSIC, Madrid (Spain)

    2009-05-15

    Structural and magnetic changes on invar Fe{sub 64}Ni{sub 36} alloy (T{sub C}=500 K) produced by mechanical milling followed by heating up to 1073 K, were investigated by neutron diffraction, magnetization measurements, X-ray diffraction under high pressures and X-ray absorption at both Fe and Ni K-edges. We argue that the strain induced in the Fe{sub 64}Ni{sub 36} material after this treatment mainly affects the Fe sites due to the magnetovolume coupling, the most notorious feature being the increase of the Curie temperature ({delta}T{sub C}=70 K). (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Effects of fluence and fluence rate of proton irradiation upon magnetism in Fe65Ni35 Invar alloy

    Science.gov (United States)

    Matsushita, Masafumi; Wada, Hideki; Matsushima, Yasushi

    2015-11-01

    Curie temperature, TC, of the Fe-Ni Invar alloys increase due to irradiation with electron and some kinds of ions. In this study, proton irradiation effects upon magnetism in an Fe65Ni35 alloy have been investigated. It is found that the increment of TC, ∆TC, increases with increasing fluence. The magnetic hysteresis curve of the alloy was found to be unaffected by irradiation. Comparing ∆TC and the calculated energy transfer from the ions to the sample, it seemed that ∆TC was found to be related to the number of vacancies formed in nuclear collision events. In addition, ∆TC was influenced by the fluence rate, i.e., the deposited energy per unit time.

  3. First-principles modeling of the Invar effect in Fe65Ni35 by the spin-wave method

    Science.gov (United States)

    Ruban, A. V.

    2017-05-01

    Thermal lattice expansion of the Invar Fe0.65Ni0.35 alloy is investigated in first-principles calculations using the spin-wave method, which is generalized here for the ferromagnetic state with short-range order. It is shown that magnetic short-range order effects make a substantial contribution to the equilibrium lattice constant and cannot be neglected in the accurate ab initio modeling of the thermal expansion in Fe-Ni alloys. We also demonstrate that at high temperatures, close to and above the magnetic transition, magnetic entropy associated with transverse and longitudinal spin fluctuations yields a noticeable contribution to the equilibrium lattice constant. The obtained theoretical results for the temperature dependent lattice constant are in semiquantitative agreement with the experimental data apart from the region close the magnetic transition.

  4. Moessbauer and x-ray study of mechanically alloyed Fe-Ni alloys around the Invar composition

    Energy Technology Data Exchange (ETDEWEB)

    Valderruten, J F; Perez Alcazar, G A [Departamento de Fisica, Universidad del Valle, A. A. 25360, Cali (Colombia); Greneche, J M [Laboratoire de Physique de l' Etat Condense, UMR CNRS 6087, Universite du Maine, Avenue Olivier Messiaen, F-72085 Le Mans cedex (France)

    2008-12-03

    Fe{sub 100-x}Ni{sub x} powders (22.5{<=}x{<=}40 at.%) mechanically alloyed (MA) for 10 h were characterized by x-ray diffraction (XRD) and transmission {sup 57}Fe Moessbauer spectrometry (TMS). In all of this composition range, the nanostructured alloys consist of two crystalline phases, body-centred cubic (BCC) and face-centred cubic (FCC). The Moessbauer spectra were fitted by means of a new fitting model involving two hyperfine magnetic field distributions (HMFDs), and a narrow singlet. One HMFD corresponds to the ferromagnetic BCC grains (tetrataenite), and the other to the ferromagnetic FCC grains (taenite), and the narrow singlet to paramagnetic FCC grains (antitaenite or superparamagnetic FCC grains). The Ni content dependence of the hyperfine field at {sup 57}Fe nuclei of the FCC phase gives evidence for some jump at about 32.5 at.% Ni, attributed to Invar anomaly.

  5. Mössbauer and x-ray study of mechanically alloyed Fe Ni alloys around the Invar composition

    Science.gov (United States)

    Valderruten, J. F.; Pérez Alcázar, G. A.; Grenèche, J. M.

    2008-12-01

    Fe100-xNix powders (22.5alloyed (MA) for 10 h were characterized by x-ray diffraction (XRD) and transmission 57Fe Mössbauer spectrometry (TMS). In all of this composition range, the nanostructured alloys consist of two crystalline phases, body-centred cubic (BCC) and face-centred cubic (FCC). The Mössbauer spectra were fitted by means of a new fitting model involving two hyperfine magnetic field distributions (HMFDs), and a narrow singlet. One HMFD corresponds to the ferromagnetic BCC grains (tetrataenite), and the other to the ferromagnetic FCC grains (taenite), and the narrow singlet to paramagnetic FCC grains (antitaenite or superparamagnetic FCC grains). The Ni content dependence of the hyperfine field at 57Fe nuclei of the FCC phase gives evidence for some jump at about 32.5 at.% Ni, attributed to Invar anomaly.

  6. Bonding of Cf/SiC composite to Invar alloy using an active cement, Ag-Cu eutectic and Cu interlayer

    Science.gov (United States)

    Lei, Zhao; Xiaohong, Li; Jinbao, Hou; Qiang, Sun; Fuli, Zhang

    2012-10-01

    The interfacial microstructures and mechanical properties of the joints formed by active cement added brazing in vacuum of Cf/SiC composite to Invar alloy, using Ag-Cu eutectic alloy and pure copper foil as braze alloy and interlayer respectively, were investigated. CuTi, Cu4Ti3, Fe2Ti and the reaction layer of TiC and Si were the predominant components at the joint interface. The maximum shear strength of the joint was 77 MPa for brazing at 850 °C for 15 min. The results show that active cement added brazing in vacuum using Ag-Cu eutectic alloy and Cu interlayer can be used successfully for joining Cf/SiC composites to Invar alloy.

  7. Comparison between wire mesh and plate electrodes during Wide-pattern machining on invar fine sheet using through-mask electrochemical micromachining

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Kwang-ho; Jin, Da-som; Kim, Seong-hyun; Lee, Eun-sang [Inha University, Incheon (Korea, Republic of)

    2017-04-15

    Many research on the fabrication of Organic light emitting diodes (OLED) shadow masks with high resolution have been carried out because of the development of the smart-display industry. It is the parts of display panel which has millions of micro holes on invar (Fe- Ni) fine sheet. Various techniques such as laser machining, chemical etching and Electrochemical micro-machining (EMM) are used to produce micro-hole arrays. In this study, Through-mask electrochemical machining (TMEMM) combine with portion of photolithography process was applied to fabricate micro-hole arrays on invar fine sheet. The sheet was coated with dry film photoresist. Two types of electrode, plate and mesh, was used to compare the influence of electrode type. The sheet was coated with dry film photoresist with micro- sized through holes. The results were compared in regard to uniformity and taper angle. Compared with the plate electrode, the mesh electrode has better uniformity and taper angle which is important criteria of OLED shadow mask. These results could be used to improve TMEMM for invar fine sheet when it is applied to fabricate micro-hole arrays and help to obtain optical uniformity and desired taper angles.

  8. Magnetization of ternary alloys based on Fe0.65Ni0.35 invar with 3d transition metal additions: An ab initio study

    Science.gov (United States)

    Onoue, Masatoshi; Trimarchi, Giancarlo; Freeman, Arthur J.; Popescu, Voicu; Matsen, Marc R.

    2015-01-01

    Smart susceptors are being developed for use as tooling surfaces in molding machines that use apply electro-magnetic induction heating to mold and form plastics or metal powders into structural parts, e.g., on aerospace and automotive manufacturing lines. The optimal magnetic materials for the induction heating process should have large magnetization, high magnetic permeability, but also small thermal expansion coefficient. The Fe0.65Ni0.35 invar alloy with its negligible thermal expansion coefficient is thus a natural choice for this application. Here, we use density functional theory as implemented through the Korringa-Kohn-Rostoker method within the coherent-potential approximation, to design new alloys with the large magnetization desired for smart susceptor applications. We consider the Fe0.65-xNi0.35-yMx+y alloys derived from Fe0.65Ni0.35 invar adding a third element M = Sc, Ti, V, Cr, Mn, or Co with concentration (x + y) reaching up to 5 at. %. We find that the total magnetization depends linearly on the concentration of M. Specifically, the early 3d transition metals from Sc to Cr decrease the magnetization with respect to that of the invar alloy whereas Mn and Co increase it.

  9. Effect of current compliance and voltage sweep rate on the resistive switching of HfO2/ITO/Invar structure as measured by conductive atomic force microscopy

    Science.gov (United States)

    Wu, You-Lin; Liao, Chun-Wei; Ling, Jing-Jenn

    2014-06-01

    The electrical characterization of HfO2/ITO/Invar resistive switching memory structure was studied using conductive atomic force microscopy (AFM) with a semiconductor parameter analyzer, Agilent 4156C. The metal alloy Invar was used as the metal substrate to ensure good ohmic contact with the substrate holder of the AFM. A conductive Pt/Ir AFM tip was placed in direct contact with the HfO2 surface, such that it acted as the top electrode. Nanoscale current-voltage (I-V) characteristics of the HfO2/ITO/Invar structure were measured by applying a ramp voltage through the conductive AFM tip at various current compliances and ramp voltage sweep rates. It was found that the resistance of the low resistance state (RLRS) decreased with increasing current compliance value, but resistance of high resistance state (RHRS) barely changed. However, both the RHRS and RLRS decreased as the voltage sweep rate increased. The reasons for this dependency on current compliance and voltage sweep rate are discussed.

  10. Improved magnetic and electrical properties of Cu doped Fe-Ni invar alloys synthesized by chemical reduction technique

    Science.gov (United States)

    Ahmad, Sajjad; Ziya, Amer Bashir; Ashiq, Muhammad Naeem; Ibrahim, Ather; Atiq, Shabbar; Ahmad, Naseeb; Shakeel, Muhammad; Khan, Muhammad Azhar

    2016-12-01

    Fe-Ni-Cu invar alloys of various compositions (Fe65Ni35-xCux, x=0, 0.2, 0.6, 1, 1.4 and 1.8) were synthesized via chemical reduction route. These alloys were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM) techniques. The XRD analysis revealed the formation of face centered cubic (fcc) structure. The lattice parameter and the crystallite size of the investigated alloys were calculated and the line broadening indicated the nano-crystallites size of alloy powder. The particle size was estimated from SEM and it decreases by the incorporation of Cu and found to be in the range of 24-40 nm. The addition of Cu in these alloys appreciably enhances the saturation magnetization and it increases from 99 to 123 emu/g. Electrical conductivity has been improved with Cu addition. The thermal conductivity was calculated using the Wiedemann-Franz law.

  11. Direct measurement of magnetization isotherms of Fe64Ni36 Invar alloy in a diamond anvil cell

    Science.gov (United States)

    Kamarád, J.; Míšek, M.; Arnold, Z.

    2014-10-01

    Magnetization isotherms of the Fe64Ni36 Invar alloy have been measured under pressure up to 5.3 GPa in magnetic field up to 5 T using a diamond anvil cell and SQUID magnetometer. The unambiguous change of the pressure parameter dlnMS/dP (from -9 to -13×10-2 GPa-1) has been observed in a narrow pressure interval from 2.5 to 3.5 GPa at all temperatures in the range from 5 to 300 K. The pressure interval, where the sharp decrease in magnetization was observed, coincides with the critical pressures of the pressure-induced decrease in Fe-moment that were determined by the X-ray Magnetic Circular Dichroism and the X-ray Emission Spectra studies, recently. The pronounced decrease in the Curie temperature of the Fe64Ni36 alloy under pressure, dTC/dP = -44 ±2 K/GPa, has been confirmed.

  12. Desarrollo de materiales compuestos Invar-Carbono y caracterización con técnicas pulvimetalúrgicas avanzadas

    OpenAIRE

    Pretus Yagüe, Miguel

    2014-01-01

    Los materiales compuestos de matriz metálica (MCMMs) son materiales muy atractivos para ser empleados en multitud de aplicaciones y áreas de la ingeniería. Aunque existen muchos casos de estudio relacionados con este tipo de materiales, la mayoría de los esfuerzos han sido dirigidos a potenciar y desarrollar materiales compuestos de matriz polimérica. Este proyecto tiene como interés fundamental analizar un material compuesto formado por Invar (aleación de hierro y níquel) que constituirá el ...

  13. A study on the influence of trace elements (C, S, B, Al, N) on the hot ductility of the high purity austenitic alloy Fe-Ni 36% (INVAR)

    Energy Technology Data Exchange (ETDEWEB)

    Simonetta-Perrot, M.T.

    1994-11-01

    In order to study the damage mechanisms leading to the ductility decrease of the Invar alloy at 600 C, a high-purity Fe-Ni 36% sample has been doped with trace elements with the purpose of identifying the role of sulfur, sulfur with Al N or B N precipitates and sulfur with boron, on the ductility, the failure modes, the intergranular damage and the plastic deformation mechanisms prior to failure. A new AES segregation quantification method has been used to study the kinetics and thermodynamics of intergranular and surface segregations and determine the relation between sulfur segregation and grain joint fragility. refs., figs., tabs.

  14. Volume and structural study of Fe64Mn36 anti-ferromagnetic Invar alloy under high pressure

    Science.gov (United States)

    Matsushita, M.; Nakano, S.; Ohfuji, H.; Yamada, I.; Kikegawa, T.

    2011-03-01

    We have investigated the pressure variation of the volume and structure of an FCC Fe64Mn36 anti-ferromagnetic Invar alloy. The inclination of the pressure-volume (P-V) curve of the FCC structure becomes discontinuous at a pressure of 4 GPa. According to the bulk modulus at zero pressure estimated by the Birch-Murnaghan equation of state, the pressure between 4 and 10 GPa is 33 GPa larger than that at a pressure below 4 GPa. Considering previous experiments on magnetism at high pressure the Neel temperature at 4 GPa almost decreases to room temperature. These results suggest that the increase in the bulk modulus by 33 GPa can be attributed to the pressure-induced magnetic phase transition from anti-ferromagnetism to paramagnetism. Volume at zero pressure was estimated using the Birch-Murnaghan equation of state. The volume of FCC structure in the anti-ferromagnetic state was 1.17% larger than the volume in the paramagnetic state, namely, the spontaneous magnetostriction was 1.17%. Pressure-induced structural transition from FCC to HCP occurs with an increase in the pressure, especially at up to 5 GPa. The value of c/a is 1.62; this value almost corresponds to that of an ideal HCP structure. The bulk modulus of the HCP structure estimated by the Birch-Murnaghan equation of state is larger than that of the FCC structure, and the volume/atom ratio is smaller than that of the FCC structure.

  15. Neutron powder thermo-diffraction in mechanically alloyed Fe{sub 64}Ni{sub 36} invar alloy

    Energy Technology Data Exchange (ETDEWEB)

    Gorria, Pedro, E-mail: pgorria@uniovi.e [Departamento de Fisica, Universidad de Oviedo, Avda. Calvo Sotelo s/n, Oviedo 33007, Asturias (Spain); Martinez-Blanco, David [Unidad de Magnetometria, SCT' s, Universidad de Oviedo, Julian Claveria 8, 33006 Oviedo (Spain); Blanco, Jesus A. [Departamento de Fisica, Universidad de Oviedo, Avda. Calvo Sotelo s/n, Oviedo 33007, Asturias (Spain); Smith, Ronald I. [ISIS Facility, RAL, Chilton, Didcot, Oxon OX11 0QX (United Kingdom)

    2010-04-16

    Nanostructured Fe{sub 64}Ni{sub 36} alloy has been obtained using high-energy ball milling for 35 h of milling time, Fe{sub 64}Ni{sub 36} MA-35 h. The initial as-milled Fe{sub 64}Ni{sub 36} MA-35 h powders are inhomogeneous, showing a majority phase with a face-centred cubic (fcc) crystal structure [88(2)%] and a minority phase with body-centred cubic (bcc) crystal structure [7(2)%]. The evolution of the microstructure with temperature between 300 K and 1100 K has been followed by means of in situ neutron powder thermo-diffraction experiments. The room temperature values for the mean crystalline size and the mechanical-induced microstrain of the fcc phase in the as-milled sample are {approx}10 nm and {approx}0.7%, respectively. Moreover, after heating the Fe{sub 64}Ni{sub 36} MA-35 h powders up to 1100 K, an increase of around 65 K in the Curie temperature respect to that of the commercial coarse-grained alloy of the same composition is observed. The latter together with the observed temperature dependence of the lattice parameter suggests that the Fe{sub 64}Ni{sub 36} MA-35 h sample subjected to the heating process exhibits invar behaviour. On heating up to 1100 K thermal relaxation of the microstructure occurs giving rise to grain growth above 100 nm, nearly vanishing values for the maximum strain, and the transformation of the bcc phase into the fcc one above 800 K, being the latter stable in subsequent heating-cooling processes.

  16. Effect of MeV ion irradiation on the coefficient of thermal expansion of Fe-Ni Invar alloys: A combinatorial study

    Energy Technology Data Exchange (ETDEWEB)

    Zheng Xuan, E-mail: xuan.zheng@seagate.com [Department of Materials Science and Engineering, Frederick-Seitz Materials Research Laboratory, University of Illinois, Urbana, IL 61801 (United States); Cahill, David G. [Department of Materials Science and Engineering, Frederick-Seitz Materials Research Laboratory, University of Illinois, Urbana, IL 61801 (United States); Zhao Jicheng [Department of Materials Science and Engineering, Ohio State University, Columbus, OH 43210 (United States)

    2010-02-15

    The effect of low-dose MeV ion irradiation on the thermal conductivity and coefficient of thermal expansion (CTE) of Fe-Ni alloys has been studied over the entire composition range using a combinatorial method. With our experimental precision of {+-}5%, the thermal conductivity of Fe-Ni alloys is unchanged by 2.3MeVAr{sup +} irradiation at a fluence of 1.2x10{sup 14}ionscm{sup -2}. The CTE of Fe-Ni Invar alloys with Ni concentrations between 30 and 37 at.% increases significantly upon 2.3MeVAr{sup +} irradiation. At the Invar composition of Fe{sub 65}Ni{sub 35}, the CTE increases from 0.5x10{sup -6}K{sup -1} before ion irradiation to 4.3x10{sup -6}K{sup -1} after irradiation for an ion fluence of 1.2x10{sup 14}ionscm{sup -2} or, equivalently, 0.1 displacements per atom. We attribute this increase in CTE to changes in atomic short-range order created by ion irradiation.

  17. The enhanced range of temperature for coefficient of low thermal expansion, electrical and thermal conductivities of Cu substituted Fe-Ni invar alloys

    Science.gov (United States)

    Khan, S. A.; Ziya, A. B.; Ibrahim, A.; Atiq, S.; Ahmad, N.; Bashir, F.

    2016-03-01

    Six alloys of Fe65Ni35-x Cu x (x = 0, 0.2, 0.6, 1, 1.4, 1.8 at.%) have been prepared by conventional arc-melting technique and characterized by utilizing high temperature x-ray diffraction (HTXRD) technique at a range from room temperature to 773 K for determination of phase, lattice parameter (a), coefficient of thermal expansion (α(T)), mean square amplitude of vibration (\\bar{{u}2}), characteristic Debye temperature (ΘD), electrical resistivity (ρ) and thermal conductivity (κ). The studies showed that these alloys form face centered cubic structure (fcc) throughout the investigated temperature range. The values of α(T) were found to be comparable to those for conventional Fe-Ni invar alloys but have increased temperature span to a significant extent. The mean square amplitude of vibration (\\bar{{u}2}) and Debye temperature were found to remain almost unchanged in the invar temperature range, whereas the electrical and thermal conductivity were found to improve.

  18. Spin-wave dynamics in Invar Fe sub 6 sub 5 Ni sub 3 sub 5 alloy studied by small-angle polarized neutron scattering

    CERN Document Server

    Grigoriev, S V; Deriglazov, V V; Okorokov, A I; Dijk, N H V; Brück, E; Klaasse, J C P; Eckerlebe, H; Kozik, G

    2002-01-01

    Spin dynamics in Fe sub 6 sub 5 Ni sub 3 sub 5 Invar alloy has been studied by left-right asymmetry of small-angle polarized neutron scattering below T sub C =485 K in external magnetic fields of H=0.05-0.25 T inclined relative to the incident beam. The spin-wave stiffness D and the damping GAMMA were obtained by fitting the antisymmetrical contribution to the scattering. The spin-wave stiffness extrapolated by a (T/T sub C) sup 5 sup / sup 2 law to T=0 K is D sub 0 =117+-2 meVA sup 2 , which is somewhat smaller than the spin-wave stiffness obtained by triple-axis spectrometry. (orig.)

  19. Formation of an L10 superstructure in austenite upon the α → γ transformation in the invar alloy Fe-32% Ni

    Science.gov (United States)

    Kabanova, I. G.; Sagaradze, V. V.; Kataeva, N. V.

    2011-09-01

    Structure of a metastable austenitic invar alloy Fe-32% Ni preliminarily quenched for martensite and subjected to α → γ transformation using slow heating to various temperatures (430-500°C) with the formation of variously oriented nanocrystalline lamellar austenite, which was subjected to an additional annealing at 280°C (below the calculated temperature of ordering of the γ phase), has been studied electron-microscopically. An electron diffraction analysis revealed the presence of an L10 superstructure in the disperse nickel-enriched nanocrystalline γ phase both after annealing at 280°C and in the unannealed alloy immediately after α → γ transformation upon slow heating to 430°C.

  20. Observation of a composition-controlled high-moment/low-moment transition in the face centered cubic Fe-Ni system: Invar effect is an expansion, not a contraction

    International Nuclear Information System (INIS)

    Lagarec, K.; Rancourt, D.G.; Bose, S.K.; Sanyal, B.; Dunlap, R.A.

    2001-01-01

    We report the first conclusive observation of a high-moment (HM)/low-moment (LM) transition occurring in face centered cubic Fe-Ni alloys. 57 Fe Moessbauer isomer shifts give local electronic densities that exhibit a large discontinuity of ∼0.4 el./a 0 3 at the transition that spans the concentration range ∼60-80 at% Fe, in agreement with ab initio predictions. Our electronic structure calculations give an isomer shift discontinuity at a comparable composition and of the same magnitude as the observed one. This identification of the HM/LM transition in Fe-Ni allows an interpretation of the compositional dependence of the lattice parameter (at room temperature or extrapolated to T=0 K) in which it is seen that the Invar effect is an expansion, relative to normal HM non-magnetovolume active behavior, not a contraction as is required in all two-γ-state-like interpretations. Indeed, the Invar effect and the HM/LM transition are seen as two distinct and competing phenomena that dominate at different compositions and that arise from different features of the electronic structure: a large inter-atomic separation dependence of the magnetic exchange interaction between large local moments versus instability of the local moment magnitude, respectively. In the Fe-rich alloys including Invar (Fe 65 Ni 35 ), we observe temperature-induced changes in electronic density that follow the spontaneous magnetization curves and that are both consistent with the associated loss of local moment orientation order and inconsistent with a significant loss of local moment magnitude. This establishes that Invar is predominantly a HM phase at all temperatures where an Invar effect occurs. In the most Fe-rich alloys that have LM ground states (including γ-Fe), we find that thermal stabilization of the HM phase occurs at high temperatures (i.e., increase of local moment magnitude with increasing temperature), along a continuum of homogeneous phases between the LM and HM extremes, in a

  1. Effects of fluence and fluence rate of proton irradiation upon magnetism in Fe{sub 65}Ni{sub 35} Invar alloy

    Energy Technology Data Exchange (ETDEWEB)

    Matsushita, Masafumi, E-mail: matsushita.masafumi.me@ehime-u.ac.jp [Department of Mechanical Engineering, Ehime University, 3-Bunkyocho, Matsuyama 790-8977 (Japan); Wada, Hideki [Department of Mechanical Engineering, Ehime University, 3-Bunkyocho, Matsuyama 790-8977 (Japan); Matsushima, Yasushi [Department of Physics, Okayama University, 2-naka-tsushima, Kitaku, Okayama 700-8530 (Japan)

    2015-11-15

    Curie temperature, T{sub C}, of the Fe-Ni Invar alloys increase due to irradiation with electron and some kinds of ions. In this study, proton irradiation effects upon magnetism in an Fe{sub 65}Ni{sub 35} alloy have been investigated. It is found that the increment of T{sub C,} ∆T{sub C}, increases with increasing fluence. The magnetic hysteresis curve of the alloy was found to be unaffected by irradiation. Comparing ∆T{sub C} and the calculated energy transfer from the ions to the sample, it seemed that ∆T{sub C} was found to be related to the number of vacancies formed in nuclear collision events. In addition, ∆T{sub C} was influenced by the fluence rate, i.e., the deposited energy per unit time. - Highlights: • Proton irradiation effect on T{sub C} of Fe{sub 65}Ni{sub 35} was investigated. • Increment of T{sub C}, ∆T{sub C}, was confirmed in ion passed through and stopped samples. • The relationships among ∆T{sub C} and the deposited energy and vacancies were discussed. • It was reasonable to consider that ∆T{sub C} was related to the number of vacancies. • ∆T{sub C} was influenced by fluence rate, i.e. the energy deposition rate.

  2. Enhancement of Curie Temperature (T c) and Magnetization of Fe-Ni Invar alloy Through Cu Substitution and with He+2 Ion Irradiation

    Science.gov (United States)

    Khan, Sajjad Ahmad; Ziya, Amer Bashir; Ibrahim, Ather; Atiq, Shabbar; Usman, Muhammad; Ahmad, Naseeb; Shakeel, Muhammad

    2016-04-01

    The magnetic properties of ternary Fe-Ni-Cu invar alloys are affected by ion irradiation, which goes on increasing with increasing ion fluence (Φ), and by increasing Cu content. In the present study, the ions used are He+2 with 2 MeV energy and with 1 × 1013 cm-2, 1 × 1014 cm-2, 5 × 1014 cm-2, 1 × 1015 cm-2 and 5 × 1015 cm-2 fluence (dose) for irradiation purpose. The face centered cubic structure of the alloy was investigated after ion irradiation using x-ray diffraction (XRD) and found unchanged. However, the peaks become broader with increasing ion dose. Additionally, the lattice fluctuations were observed in XRD study. Curie temperature (T c) is also increased after irradiation. Many factors are considered here for the reason for increasing T c, such as the stopping of incident ions, atomic mixing effect at micro scale level owing to ion irradiation, which might change local concentration and ordering already reported in diffuse scattering, and as a result the Fe-Fe interatomic distance and the Fe-Fe coupling are changed. A comparative study shows that the effect of irradiation on T c and magnetization with increasing ion fluence is more distinctive than the addition of Cu.

  3. Properties of Ni{sub 1-x}Fe{sub x} (0.1 < x < 0.9) and Invar (x = 0.64) alloys obtained by electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Tabakovic, Ibro, E-mail: ibro.m.tabakovic@seagate.co [Seagate Technology, 7801 Computer Avenue South, Bloomington, MN 55435 (United States); Inturi, Venkateswara; Thurn, Jeremy; Kief, Mark [Seagate Technology, 7801 Computer Avenue South, Bloomington, MN 55435 (United States)

    2010-09-01

    Electrodeposition of Ni{sub 1-x}Fe{sub x} (x = 0.1-0.9) films was carried out from a chloride plating solution containing saccharin as an organic additive at a constant current density (5 mA/cm{sup 2}) and a controlled pH of 2.5. X-ray diffraction studies revealed the existence of an fcc, or {gamma} phase, in the range of 10-58 wt.% Fe, a mixed fcc/bcc phase in the range of 59-60 wt.% Fe, and a bcc, or {alpha} phase in the range of 64-90 wt.% Fe. The saturation magnetization, B{sub s}, of electrodeposited Ni{sub 1-x}Fe{sub x} alloys at the room temperature was found to increase with the increase of Fe-content and follows the Slater-Pauling curve, but deviates from as-cast bulk NiFe alloys. The coefficient of thermal expansion, CTE, of electrodeposited alloys at room temperature also deviates from as-cast bulk NiFe alloys. Annealing of {alpha}-Ni{sub 36}Fe{sub 64} alloy results in a martensitic {alpha} {yields} {gamma} phase transformation, which takes place between 300 and 400 {sup o}C. It was demonstrated that thermal treatment above 400 {sup o}C was necessary to obtain magnetic and mechanical properties similar to those to conventional Invar alloy. Annealing of {alpha}-Ni{sub 36}Fe{sub 64} alloy at 700 {sup o}C brings about a decrease of B{sub s} from 1.75 to 0.45 T. By controlling the annealing conditions of {alpha} {yields} {gamma} martensitic transformation, it is possible to adjust the CTE of Ni{sub 36}Fe{sub 64} alloy over the broad limits from 2.7 to 8.7 x 10{sup -6}/{sup o}C.

  4. Volume and structural study of Fe{sub 64}Mn{sub 36} anti-ferromagnetic Invar alloy under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Matsushita, M., E-mail: matsushita@eng.ehime-u.ac.j [Department of Mechanical Engineering, Graduate School of Science and Engineering, Ehime University, 3-Bunkyocho, Matsuyama 790-0826 (Japan); Nakano, S. [National Institute for Materials Science, Tsukuba, Ibaraki 305-0044 (Japan); Ohfuji, H. [Geodynamics Research Center, Ehime University, 2-Bunkyocho, Matsuyama 790-0826 (Japan); Yamada, I. [Department of Chemistry and Biology, Graduate School of Science and Engineering, Ehime University, 2-Bunkyocho, Matsuyama 790-0826 (Japan); Kikegawa, T. [High Energy Accelerator Research Organization, Tsukuba 305-0801 (Japan)

    2011-03-15

    We have investigated the pressure variation of the volume and structure of an FCC Fe{sub 64}Mn{sub 36} anti-ferromagnetic Invar alloy. The inclination of the pressure-volume (P-V) curve of the FCC structure becomes discontinuous at a pressure of 4 GPa. According to the bulk modulus at zero pressure estimated by the Birch-Murnaghan equation of state, the pressure between 4 and 10 GPa is 33 GPa larger than that at a pressure below 4 GPa. Considering previous experiments on magnetism at high pressure the Neel temperature at 4 GPa almost decreases to room temperature. These results suggest that the increase in the bulk modulus by 33 GPa can be attributed to the pressure-induced magnetic phase transition from anti-ferromagnetism to paramagnetism. Volume at zero pressure was estimated using the Birch-Murnaghan equation of state. The volume of FCC structure in the anti-ferromagnetic state was 1.17% larger than the volume in the paramagnetic state, namely, the spontaneous magnetostriction was 1.17%. Pressure-induced structural transition from FCC to HCP occurs with an increase in the pressure, especially at up to 5 GPa. The value of c/a is 1.62; this value almost corresponds to that of an ideal HCP structure. The bulk modulus of the HCP structure estimated by the Birch-Murnaghan equation of state is larger than that of the FCC structure, and the volume/atom ratio is smaller than that of the FCC structure. - Research highlights: > We have investigated the pressure variation of volume and structure of FCC Fe{sub 64}Mn{sub 36} alloy. > We discovered that the change in inclination of the pressure-volume (P-V) curve of the FCC structure becomes discontinuous at a pressure of 4 GPa. This pressure corresponds to the Neel temperature, which decreases down to room temperature. > Further we estimated bulk modulus and volume at zero pressure using the Birch-Murnaghan equation of state. As a result, we have demonstrated that anti-ferromagnetism has very close relationship with the

  5. Hyperfine interactions and local environment effects in Fe{sub x}Ni{sub 100-x} (x = 55-67) Invar alloys: {sup 57}Fe Moessbauer spectroscopy data at 5 K

    Energy Technology Data Exchange (ETDEWEB)

    Delyagin, N.N., E-mail: delyagin@srd.sinp.msu.r [Institute of Nuclear Physics, Moscow State University, 119991 Moscow (Russian Federation); Erzinkyan, A.L.; Parfenova, V.P.; Rozantsev, I.N. [Institute of Nuclear Physics, Moscow State University, 119991 Moscow (Russian Federation)

    2010-07-09

    A systematic study of the magnetic hyperfine field distribution for {sup 57}Fe in the Invar alloys Fe{sub x}Ni{sub 100-x} (x = 55, 60, 63, 65 and 67) have been performed by Moessbauer spectroscopy technique at 5 K. The composition dependences of the magnetic hyperfine fields (B{sub hf}), isomer shifts and relative intensities of the magnetic subspectra were measured and analyzed. The reliable data on the correspondence between the B{sub hf} magnitude and the type of locale atomic configuration were obtained. It is confirmed that the Fe-Ni Invar alloys in their ground state are predominantly collinear ferromagnets with well-defined atomic magnetic moments. Particular emphasis has been placed on the low-field (LF) component of the distribution (B{sub hf} = 1.4 and 2.5 T) which is considered as corresponding to the Fe sites with the antiferromagnetic (AFM) alignment of the magnetic moment. The most striking feature of the LF component is the anomalous positive isomer shift that corresponds to a large reduction of the local electron density at the Fe sites. It may be proposed that the volume effect is one of the plausible reasons for the increase in the IS value for LF components. In this case, we should suggest that the formation of the AFM sites leads to some increase in the local atomic volume. The possible influence of the competition between energetically satisfied and unsatisfied exchange bonds on the stability of the AFM states of the Fe atoms is briefly discussed.

  6. Effect of external magnetic field on valence-electron structures of Fe and Ni in Invar, Permalloy and the other Fe-Ni alloys by using Kβ-to-Kα X-ray intensity ratios.

    Science.gov (United States)

    Alım, Bünyamin; Han, İbrahim; Demir, Lütfü

    2016-06-01

    The effect of external magnetic field on the valence-electron structures of Fe and Ni in various Fe-Ni alloy compositions was investigated by using X-ray fluorescence spectroscopy. Firstly, Kβ-to-Kα X-ray intensity ratios of Fe and Ni in Invar (Fe0.64Ni0.36), Permalloy (Fe0.20Ni0.80) and FexNi1-x (x=0, 0.40, 0.52, 0.55, 0.61, and 1) alloys were measured without any magnetic field and under 0.5 and 1T external magnetic fields, separately. Later, the valence-electron structures of Fe and Ni in both pure form and alloys were obtained by comparison of measured X-ray intensity ratios with the results of multi-configurations Dirac-Fock (MCDF) calculations. The results obtained for valence-electron structures of Fe and Ni in various Fe-Ni alloys were evaluated in terms of magnetic field effect, delocalization and/or charge transfer phenomena. The results have shown that valence electron structure of Fe and Ni in Fe-Ni alloys are dependent on both external magnetic field and concentration of alloy elements. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Chemical-milling solution for invar alloy

    Science.gov (United States)

    Batiuk, W.

    1980-01-01

    Excellent surface finishes and tolerances are achieved using two formulations. Solution A gives finish of 3.17 micrometers after milling at 57 to 63 deg C. Constituents of A are: Hydrofluoric acid (70%), 5,8 oz/gal; nitric acid (40-42) degrees Baume), 40 oz/gal. Alternative solution gives 2.16 micrometer finish, and differs from A by addition of 7% phosphoric acid. Formulations eliminate channeling at root fillets, dishing, island formation, and overhangs.

  8. Copper-rich invar by mechanical alloying

    Science.gov (United States)

    O'Donnell, K.; Qi, Qinian; Ilyushin, A. S.; Coey, J. M. D.

    1993-05-01

    An fcc alloy of composition Fe 64Cu 26Cr 7Ni 3 with a0 = 0.362 nm and an average crystalline size of 5 nm was produced by high-energy ball milling iron and copper powder in a stainless-steel container. The average number of electrons per atom is 8.7. The Curie temperature of the alloy is 410 K and the room-temperature magnetization is 48 JT -1 kg -1. The Mössbauer spectrum at 15 K shows a broad distribution of hyperfine field with an average of 15.6 T, which indicates coexistence of high and low moment states for iron. The alloy decomposes exothermically at 775 K to yield a mixture of bcc and fcc phases, but 50% of the iron remains in the fcc form with a low moment.

  9. Neutron irradiation effects on magnetic properties of iron-nickel Invar alloys

    International Nuclear Information System (INIS)

    Morita, H.; Tanji, Y.; Hiroyoshi, H.; Nakagawa, Y.

    1983-01-01

    The Curie temperature of fcc Fe-Ni containing 30-50% Ni is reaised by neutron irradiation, although no appreciable change is detected in the X-ray diffraction pattern. These results are related to a tendency to two-phase separation of the fcc phase. (orig.)

  10. On the existence of declared 9 R phase in Fe-Ni invar alloy

    Science.gov (United States)

    Kabanova, I. G.; Sagaradze, V. V.; Kataeva, N. V.

    2016-07-01

    An analysis of recently reported electron diffraction patterns suggests that metastable austenitic Fe-32Ni alloy subjected to α → γ transformation upon slow heating does not exhibit any signs of formation of the 9 R phase; the conventional nanocrystalline γ phase with an fcc lattice is formed instead. Extended lamellae with a layered structure, erroneously identified as a new phase of the (3 R + 9 R) type in Fe-32Ni alloy, are conventional twinning (midrib) regions of each initial α crystal, in which γ-phase twin nanolamellae are formed upon heating.

  11. Grain size effect on martensitic transformation behavior in Fe-Ni invar alloys

    Energy Technology Data Exchange (ETDEWEB)

    Aikawa, Yoshikazu [Metal Powder Manufacturing and Sales Division, Sanyo Special Steel Co., Ltd, 3007 Nakashima, Shikama-ku, Himeji 672-8677 (Japan); Terai, Tomoyuki; Kakeshita, Tomoyuki [Department of Material Science and Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2009-05-01

    We investigated the grain size effect on martensitic transformation behavior in Fe-30at.%Ni powder and ribbon specimens. The powder specimen with a particle size of 5 um does not show an athermal martensitic transformation but does show an isothermal martensitic transformation after an incubation time of about 10{sup 4} s at 205 K. On the other hand, the powder specimen with a particle size of 20 um shows an athermal martensitic transformation at 150 K. The value of M{sub s} is much lower than that of the single crystal and of bulk specimens. However, the M{sub s} temperature of a ribbon specimen with an average grain size of 15 um is found to be almost identical to that of the single crystal and of bulk specimens. Considering these results, the athermal martensitic transformation is suppressed by the decrease in particle size if grains do not have grain boundaries.

  12. The effect of temperature on the structural and magnetic behaviour of Fe-Ni Invar alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kadziolka-Gawel, M; Zarek, W; Popiel, E, E-mail: mariolakadz@op.p [Institute of Physics, University of Silesia, 4 Uniwersytecka Str., 40-407 Katowice (Poland)

    2010-03-01

    The crystal structure and magnetic properties of polycrystalline Fe{sub 1-x}Ni{sub x} alloys with x = 0.30, 0.325 and 0.375 were investigated in the temperature range 20K

  13. Formation of boron solid solution in Fe-Ni invar upon severe plastic deformation

    Science.gov (United States)

    Shabashov, V. A.; Litvinov, A. V.; Kataeva, N. V.; Lyashkov, K. A.; Novikov, S. I.; Titova, S. G.

    2011-09-01

    Mössbauer spectroscopy, X-ray diffraction, electron microscopy, and magnetic susceptibility measurements have been used to study the process of mechanical synthesis of the solid solution of boron in the matrix of an Fe-Ni alloy. The internal effective field, the Curie temperature, and the lattice parameter of the Fe-Ni austenite were found to increase after severe plastic deformation in Bridgman anvils, which is related to the incorporation of boron into the matrix and the formation of a crystalline supersaturated solid solution coexisting with metastable borides.

  14. Grain size effect on martensitic transformation behavior in Fe-Ni invar alloys

    Science.gov (United States)

    Aikawa, Yoshikazu; Terai, Tomoyuki; Kakeshita, Tomoyuki

    2009-05-01

    We investigated the grain size effect on martensitic transformation behavior in Fe-30at.%Ni powder and ribbon specimens. The powder specimen with a particle size of 5 um does not show an athermal martensitic transformation but does show an isothermal martensitic transformation after an incubation time of about 104 s at 205 K. On the other hand, the powder specimen with a particle size of 20 um shows an athermal martensitic transformation at 150 K. The value of Ms is much lower than that of the single crystal and of bulk specimens. However, the Ms temperature of a ribbon specimen with an average grain size of 15 um is found to be almost identical to that of the single crystal and of bulk specimens. Considering these results, the athermal martensitic transformation is suppressed by the decrease in particle size if grains do not have grain boundaries.

  15. Moessbauer analysis and magnetic properties of Invar Fe-Ni-C and Fe-Ni-Mn-C alloys

    International Nuclear Information System (INIS)

    Nadutov, V. M.; Svystunov, Ye. O.; Kosintsev, S. G.; Tatarenko, V. A.

    2006-01-01

    The saturation magnetization and the hyperfine magnetic field of different f.c.c. Fe-Ni based alloys containing nearby 29 at .% Ni were studied as a function of temperature and for different Carbon and Manganese contents. We have observed abnormal behaviors that are explained in terms of mixed exchange interactions between atomic spins: J NiNi (r i ) FeFe (r i ) > 0, J NiFe (r i ) < 0.

  16. Effect of magnetism and atomic order on static atomic displacements in the Invar alloy Fe-27 at.% Pt

    Science.gov (United States)

    Sax, C. R.; Schönfeld, B.; Ruban, A. V.

    2015-08-01

    Fe-27 at.% Pt was aged at 1123 K and quenched to room temperature (RT) to set up a state of thermal equilibrium. The local atomic arrangement was studied by diffuse x-ray scattering above (at 427 K) and below (at RT) the Curie temperature as well as at RT under a saturating magnetic field. The separated short-range order scattering remained unchanged for all three states, with maxima at 100 positions. Effective pair interaction parameters determined by the inverse Monte Carlo method gave an order-disorder transition temperature of about 1088 K, close to direct experimental findings. The species-dependent static atomic displacements for the first two shells show large differences, with a strong increase in magnitude from the state at 427 K over RT to the state under saturating magnetic field. This outcome is in agreement with an increase in atomic volume of Fe with increasing local magnetic moment. Electronic-structure calculations closely reproduce the values for the static atomic displacements in the ferromagnetic state, and predict their dependence on the atomic configuration. They also reveal a strong dependence of the magnetic exchange interactions in Fe-Pt on the atomic configuration state and lattice parameter. In particular, the increase of the Curie temperature in a random state relative to that in the ordered one is demonstrated to be related to the corresponding change of the magnetic exchange interactions due to the different local atomic chemical environment. There exists a similar strong concentration dependence of the chemical interactions as in the case of magnetic exchange interactions. Theoretical effective interactions for Fe-27 at.% Pt alloy are in good agreement with experimental results, and they also reproduce well the L1 2-A1 transition temperature.

  17. A new type of FCT martensite phase in single-crystalline Fe{sub 3}Pt Invar alloy

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Masataka; Sekida, Sayaka [Department of Materials Science and Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Fukuda, Takashi, E-mail: fukuda@mat.eng.osaka-u.ac.jp [Department of Materials Science and Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Kakeshita, Tomoyuki [Department of Materials Science and Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Takahashi, Kohki; Koyama, Keiichi; Nojiri, Hiroyuki [High-Field Laboratory for Superconducting Materials, Institute for Materials Research, Tohoku University, 2-1-1 Sendai Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan)

    2011-08-25

    Highlights: {center_dot} TEM observations at room temperature reveal that the specimen is a single phase of L1{sub 2}-type structure. {center_dot} The spontaneous magnetization and magnetic susceptibility curves of Fe{sub 3}Pt with S = 0.88 have bend points at 60 K. {center_dot} XRD measurements reveal that this alloy exhibits a martensitic transformation to FCT and the transformation temperature is 60 K. {center_dot} The tetragonality c/a is larger than unity in the FCT martensite. {center_dot} This tetragonality is in contrast to the tetragonality c/a < 1generally observed in the FCT martensite with S < 0.8. - Abstract: Martensitic transformation in a highly ordered Fe{sub 3}Pt has been investigated by magnetization and X-ray diffraction measurements. We confirmed that a new type of face-centered tetragonal (FCT) martensite phase appears below 60 K in Fe{sub 3}Pt with a degree of order S = 0.88. The tetragonality c/a gradually increases with decreasing temperature, and is approximately 1.005 at 10 K. This is in contrast to the tetragonality c/a < 1 generally observed in the FCT martensite with a degree of order less than 0.8. The spontaneous magnetization increases in association with the transformation.

  18. Thermal properties and structure of cast carbon-containing invar and superinvar alloys after two-stage annealing

    Science.gov (United States)

    Grachev, S. V.; Filippov, M. A.; Chermenskii, V. I.; Kharchuk, M. D.; Konchakovskii, I. V.; Zhilin, A. S.; Tokarev, V. V.; Nikiforova; S. M.

    2013-07-01

    The effect of carbon content on thermal properties of cast superinvar alloys subjected to two-stage annealing is studied. It is shown that carbon improves the casting properties of the alloys but raises the temperature coefficient of linear expansion (CTLE). Two-stage high-temperature annealing makes it possible to remove carbon from the solid solution and to transfer it into graphite, which is accompanied by decrease in the CTLE.

  19. Mössbauer and X-ray study of the Fe 65 Ni 35 invar alloy obtained by mechanical alloying

    Science.gov (United States)

    Rodriguez, R. R.; Valenzuela, J. L.; Tabares, J. A.; Pérez Alcázar, G. A.

    2014-01-01

    Fe65Ni35 samples were prepared by mechanical alloying (MA) with milling times of 5, 6, 7, 10 and 11 h, using a ball mass to powder mass ratio of 20:1 and at 280 rpm. The samples were characterized by X-ray diffraction (XRD) and transmission 57Fe Mössbauer spectrometry. The X-ray diffraction pattern showed the coexistence of one body centered cubic (BCC) and two face centered cubic (FCC1 and FCC2) structural phases. The lattice parameters of these phases did not change significantly with the milling time (2.866 Å, 3.597 Å and 3.538 Å, respectively). After 10 h of milling, the X-ray diffraction pattern showed clearly the coexistence of these three phases. Hence, Mössbauer spectrometry measurements at low temperatures from 20 to 300 K of this sample were also carried out. The Mössbauer spectra were fitted using a model with three components: the first one is a hyperfine magnetic field distributions at high fields, related to the BCC phase; the second one is a hyperfine magnetic field distribution involving low hyperfine fields related to a FCC phase rich in Ni, and the third one is a singlet related to a FCC phase rich in Fe, with paramagnetic behavior. As proposed by some authors, the last phase is related with the antitaenite phase.

  20. Chemical ordering and compositions at the (001) surface of the Fe.sub.64./sub.Ni.sub.36./sub. Invar alloy

    Czech Academy of Sciences Publication Activity Database

    Ondráček, Martin; Máca, František; Kudrnovský, Josef; Redinger, J.; Biederman, A.; Fritscher, C.; Schmid, M.; Varga, P.

    2006-01-01

    Roč. 74, č. 23 (2006), 235437/-235437/7 ISSN 1098-0121 R&D Projects: GA AV ČR IAA1010214 Institutional research plan: CEZ:AV0Z10100520 Keywords : surface structure * scanning tunneling microscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.107, year: 2006

  1. Producing a gradient-composition nanocrystalline structure on nitrided surfaces of invar-type Fe-Ni alloys using megaplastic deformation

    Science.gov (United States)

    Shabashov, V. A.; Borisov, S. V.; Litvinov, A. V.; Kataeva, N. V.; Afanas'ev, S. V.; Titova, S. G.

    2014-09-01

    A nanocrystalline Fe-Ni matrix strengthened by dispersed CrN and TiN nitrides has been produced on the ion-plasma-nitrided surfaces of the austenitic Fe-Ni38-Cr15 and Fe-Ni36-Ti4 alloys using cyclic "nitride dissolution-nitride precipitation" phase transformations induced by megaplastic deformation. The high-pressure torsion of the nitrided alloys has led to the dissolution of the CrN nitrides and Ni3Ti intermetallic compounds, which appeared in the matrix, in the surface layer and to the mechanical alloying of the nitrided subsurface layer and the unnitriderd bulk of the specimens. Subsequent annealing has resulted in the formation of secondary nitrides, which propagated to a depth substantially exceeding the thickness of the original nitrided layer.

  2. USSR and Eastern Europe Scientific Abstracts Physics and Mathematics No. 35

    Science.gov (United States)

    1977-06-15

    3. USSR UDC 537.621 MAGNETIC, ELASTIC, AND THERMAL PROPERTIES OF INVAR ALLOYS Fe-Ni +8.3 atom% Mn Sverdlovsk MAGNITNYYE, MAGNITOMEKHANICHESKIYE...authors] [Text] A study was made concerning the effect of manganese in Invar alloys on their Curie point, on the components of anomaly of the...a nonuniform distri- büton of manganese in austenite blurs the ferromagnetic transformation of Invar alloys . 55 USSR UDC 537.621 MEAN MAGNETIC

  3. Metal substrates with nanometer scale surface roughness for flexible electronics

    Science.gov (United States)

    Lee, Jong-Lam; Kim, Kisoo

    2012-09-01

    In this work, we present a novel way in fabricating a metal substrate with nanometer scale in surface roughness (Ra INVAR (Invariable alloy) one (20 cm × 20 cm, Ra = 1.40 nm) were demonstrated. The INVAR film was used as a substrate for fabricating organic light emitting diodes (OLED) and organic photovoltaic (OPV). The optical and electrical characteristics of OLEDs and OPVs using the INVAR were comparable to those using a conventional ITO glass substrate.

  4. JPRS Report, Science & Technology, USSR: Materials Science

    Science.gov (United States)

    1988-01-11

    No 1, Jan 87) - a - Acoustical Characteristics of Invar Powder Alloys (V. A. Vershinin, V. I. Kostikov, et al.; POROSHKOVAYA METALLURGIYA, No 1...CHARACTERISTICS OF INVAR POWDER ALLOYS Kiev POROSHKOVAYA METALLURGIYA in Russian No 1, Jan 87 (manuscript received 21 Jan 86) pp 95-98 [Article by V. A... Invar powder alloys , 36Ni and 32NiCoCu, was made for a determination of the temperature dependence of their Young’s modulus, shear modulus

  5. SiC Design Guide: Manufacture of Silicon Carbide Products (Briefing charts)

    Science.gov (United States)

    2010-06-08

    challenges that would require an adhesive that compensates for the CTE-affected physical changes  Invar ® type alloys are recommended for cryo...Solid Metal Inserts The following chart contains information obtained by testing smooth-OD Invar type inserts into SUPERSiC and SUPERSiC-Si. Page 24...a trademark of Brush Wellman Invar ® is a trademark of ArcelorMittal UltraSic™ is a trademark of CoorsTek Zerodur® is a trademark of Schott AG Master

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

    Science.gov (United States)

    1975-01-01

    Cobalt, and the Cause of the Small Expansibility of Alloys of the Invar Type," Sci. Reports Tohoku Univ., 20, 101-23, 1931. 60 37540 Holborn, L. and Day...H., "On the Thermal Expansion of Alloys of Cobalt, Iron, and Chromium, a! a New Alloy Stainless- Invar ," Si. Rept. Tohoku Imp. Univ., 23, 265-80, 1934...USSR), 23(4), 201-3, 1967. 528 46149 Kachi, S. and Asano, H., "Concentration Fluctuations and Anomalous Properties of the Invar Alloy ," J. Phys. Soc

  7. Aspects of interaction with melt zalizonikelkysnevyh 4d-metal - Zr, Nb, Mo

    Directory of Open Access Journals (Sweden)

    Н.О. Шаркіна

    2006-01-01

    Full Text Available  There are the results of investigation of deoxidizing ability of 4d–metals in Fe–Ni–O melting systems (invars carried out by calorimetry method in isoparabolic calorimeter at 1873 K.

  8. Wire and arc addictive manufacture (WAAM) reusable tooling investigation

    OpenAIRE

    Yan, Lihao

    2013-01-01

    Composite materials have been extensively adopted by modern aircraft design and manufacture. This manufacturing process needs a forming mould. Invar alloy has been widely used to manufacture moulds for the fabrication of aeronautics and astronautics composite structures because of its unique low thermal expansion coefficient. However, Invar is very expensive and the machining and repair process is difficult and costly. Therefore, to find an alternative approach to manufactur...

  9. A Business Overview & Summary of the SM-27S/T MACHETE RDT&E Program as Undertaken by the Military Aerospace/Tactical Air Warfare Systems Division of STAVATTI

    Science.gov (United States)

    2005-06-27

    molds rather than cast/plate Invar molds for composites fabri- cation. The first stage in prototype construction is the fabrication of alloy tooling and...Airframe Systems Massachusetts Goodyear Tires Ohio Remmelle Engineering Invar Molds Minnesota Huck International Rivets California Universal Alloy Corp...tural composition. Although traditional Alclad alloys such as 7075, 7050 and 7150 aluminum are used in SM-27 wings, the MACHETE is the only COIN

  10. Troubled Partnership. A History of U.S.-Japan Collaboration on the

    Science.gov (United States)

    1995-01-01

    use of very expensive tooling manufactured from invar steel, an alloy that is quite difficult to form and machine. The Japanese manufacturing...rep- resentatives also began examining strategies for bringing down wing costs, particularly those associated with the extremely ex- pensive invar ...metal alloy tooling selected by the Japanese for the cocured composite wing.50 After extensive negotiations with MHI, and with costs continu- ing

  11. The Improved Three Axis Test Table (ITATT): Program Status and Recommendation for Completion

    Science.gov (United States)

    1990-08-01

    requirements for stiffness and stability. The conventional materials considered are aluminum, titanium, magnesium, Invar , and beryllium which are...homogeneous metal alloys . The non-standard materials considered are SiC aluminum and graphite epoxy. SiC aluminum is a metal matrix composite that mixes 20...GIMBAL DESIGN The final gimbal design is constructed of graphite/epoxy with Invar fittings in a rectangular configuration. This design is shown in

  12. Effects of Static Tensile Load on the Thermal Expansion of Gr/PI Composite Material.

    Science.gov (United States)

    1981-06-01

    is the effect of load on the thermal expansion. The effects of static tensile load on the coefficient of thermal expansion of mild steel and Invar ...thermally calibrated material ( Invar ) was used to com- pensate for apparent thermal strain. In all tests the specimens were reported to reach a... alloy (Ti-6A1-4V) specimen was performed to establish the general validity of the test method. This test was performed between room temperature and

  13. Lightweight Multifunctional Linear Cellular Alloy Ballistic Structures

    Science.gov (United States)

    2006-04-26

    densities of 10, 15 and 20 % with the dimensions shown in Table 1. The alloy compositions were high strength maraging steel (M200) and Super Invar ... alloys made from LCA processing3 are shown in Table 3. Super Invar in the as-reduced state is a ductile (25-30%) austenitic alloy . When cooled to...Final Report for Lightweight Multifunctional Linear Cellular Alloy Ballistic Structures from Structured Alloys , Inc. Joe K

  14. Ultra-High-Modulus Graphite-Epoxy Conical Shell Development. Supplement

    Science.gov (United States)

    1979-04-01

    and evaluation was conducted of candidate ring materials including both metals (aluminum, titanium, Invar , beryllium, and magnesium) and advanced...the most promise of success. All the metals introduced severe bondline thermal stress problems with Invar being the least critical. Among the...22 inch thick GY-70/X-30 graphite/epoxy (element 1), and 0. 25 inch thick aluminum alloy plates (elements 2). The length of bond L was 1. 5 inches

  15. The correct lens mount lightweighting design of thermal cycle stress in Cassegrain telescope

    Science.gov (United States)

    Hsu, M. Y.; Chang, S. T.; Huang, T. M.; Hsu, Ming-Ying

    2011-10-01

    The Cassegrain telescope system was design for space environment. The correct lens mount assembly is included as correct lens, lens mount, spacer, mount barrel and retainer. The system mass budget allocated to correct lens assembly was 5 Kg. Meanwhile, according to optical design the correct lens is made from fused silica, the lens diameter is 130 mm, and the mass is 2.3 Kg. Therefore, remain mass budget is 2.7 Kg; including the lens mount, spacer, mount barrel and retainer. The telescope system deformation is mainly caused by thermal deformation on space orbit. The correct lens mount was made from invar material in initial design. The CTE (Coefficient of Thermal Expansion) of invar is only 1* 10-6/°C, low CTE would be resistant to thermal deformation, but invar density is 8* 10-6 kg/mm3. If all components were made from invar, the total mass was over 2.7 kg. Thus, the components material would consider titanium alloy (CTE is 8.6* 10-6/°C, density is 4.43* 10-6 kg/mm3) or aluminum alloy (CTE is 23.6* 10-6/°C, density is 2.81* 10-6 kg/mm3). The titanium alloy density is 1.83 times lighter than invar, but CTE is 8.6 times higher. The aluminum alloy density is 2.84 times lighter then invar, but CTE is 23.6 times higher. The lens mount thermal deformation would effect correct lens surface wavefront error and introduce optical aberration. This article analyzes the correct lens assembly thermal deformation and optical performance in different lens mount material. From above conditions, using FEM (Finite Element Method) and optical software, simulation and optimization on the lens mount design have been performed to achieve system mass requirement.

  16. Magnetic properties of FeZrB(Cu) amorphous alloys; the effect of boron content

    International Nuclear Information System (INIS)

    Slawska-Waniewska, A.; Zuberek, R.

    1996-01-01

    The composition dependences of the basic magnetic properties indicate that Fe-rich FeZrB(Cu) amorphous alloys show behavior characteristic of Invar material. The critical Fe concentration at which the ferromagnetic order disappears is found to be 98%. (orig.)

  17. Windtunnel Capability Related to Test Sections, Cryogenics, and Computer-Windtunnel Integration.

    Science.gov (United States)

    1982-04-01

    practices. However, even for simple models, difficulties in fabrication processes have been encountered with some stainless steel alloys with which...Mo H1150M 586 1000 8% 1207 108.5 81.3 STA I NLESS STEEL INVAR ANNEALED 276 621 552 862 298.3 67.8 .. .. I NCONL 718 SOLUT ION TREATED I NCONEL 718 S N

  18. 1976 Navy Study on Superconductive Electronics, August 2-13, 1976, Naval Postgraduate School, Monterey, California

    Science.gov (United States)

    1976-01-01

    technologies is that of cycling from helium to room temperature. This problem has been alleviated by development of a super- conducting alloy to the point...Niobium-Copper- Invar -Composite Conductor for an AC Superconducting Power Transmission Cable," IEEE Transactions on Magnetics, MAG-11, 381 (1975

  19. Ambient Temperature Rechargeable Lithium Cells: State of the Art; Problems and Opportunities.

    Science.gov (United States)

    1982-12-01

    as in ref. (41), have used an alloying substrate. We have several times reported on poor results due to solution reduction reac- tivity on the...the reaction. discharge-4-CH- x + nxLi Ncharge + CH -Lin+x Here, the potential for the reduction of the polymer to its anion is invar - iably lower than

  20. Determination of the Mössbauer absorption cross section and reconstruction of hyperfine field distribution by the maximum entropy method.

    Science.gov (United States)

    Satuła, D; Szymański, K; Dobrzyński, L

    2010-07-28

    Determination of the Mössbauer absorption cross section, σ(E), and accurate reconstruction of the hyperfine field distributions of the invar alloy, Fe(64)Ni(36), by the maximum entropy method (MEM) is presented. The procedure consists of three steps: deconvolution of the Mössbauer spectra with the instrumental resolution function using MEM, nonlinear transformation of the deconvoluted spectrum into σ(E), and reconstruction of the hyperfine field distribution. In order to test the procedure of the deconvolution and correction for thickness effect, several simulated spectra with thickness parameter 1 invar alloy, measured with and without application of an external magnetic field, are discussed. The reconstruction has been made to test the earlier postulated non-collinear ferromagnetic state of invar without referring to any specific model in the analysis of the Mössbauer results. It is shown that marginal probability distribution of hyperfine magnetic field consists of the main maximum at about 28 T and a broad tail extending down to 5 T. Observed isomer shift of the main maximum is small and positive. The isomer shift decreases with magnetic field and attains negative values at the lowest fields. It is shown that the magnetic texture parameter does not depend on the hyperfine magnetic field. One thus concludes that in the invar Ni-Fe alloys, in contrast to some theoretical predictions, there is no evidence for different arrangements of the iron magnetic moments as a function of the magnetic hyperfine field.

  1. Effect of Heat Treatment on Conductivity of Metastable Alloys with Ferromagnetic and Paramagnetic Austenite

    Science.gov (United States)

    Uvarov, A. N.; Sandovskii, V. A.; Vil'danova, N. F.; Anufrieva, E. I.

    2013-11-01

    Invars N30K10T3 and N28K10T3 and nonmagnetic austenitic alloy N25Kh2T3 are studied after different kinds of treatment, i.e., quenching, mechanical phase hardening, and deformation followed by aging. The structure and the conductivity of the alloys are determined. An optimum treatment for providing high electric conductivity is suggested.

  2. Method of Analysis for Determining and Correcting Mirror Deformation due to Gravity

    Science.gov (United States)

    2014-01-01

    in place by an alumi- num alloy mount, as illustrated in Fig. 5. There are three equally spaced front pads, three corresponding and opposing rear...conceived of as levered mechanisms with flexure pivots, one end attached to Invar ® pucks and the other to the mirror cell. The pucks are adhered to the

  3. Magneto-volume effects in Fe-Cu solid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Gorria, P. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain)]. E-mail: pgorria@uniovi.es; Martinez-Blanco, D. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain); Iglesias, R. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain); Palacios, S.L. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain); Perez, M.J. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain); Blanco, J.A. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain); Fernandez Barquin, L. [Departamento CITIMAC, F. Ciencias, Universidad de Cantabria, 39005 Santander (Spain); Hernando, A. [Instituto de Magnetismo Aplicado, UCM-RENFE, 28230 Las Rozas, Madrid (Spain); Gonzalez, M.A. [Instituto de Ciencia de Materiales de Aragon, CSIC, 50009 Zaragoza (Spain); Institut Laue-Langevin, BP 156, F-38042 Grenoble Cedex 9 (France)

    2006-05-15

    The magnetic properties of Fe-Cu metastable solid solutions have been investigated by means of neutron diffraction and magnetisation measurements. These compounds exhibit ferromagnetic order with Curie temperatures above room temperature for concentrations beyond 40 at% in Fe. The magnetic moment at 5 K can reach values over 2 {mu} {sub B}, while the high field susceptibility is similar to that found in FCC-FeNi Invar alloys. These features together with the low values for the linear coefficient for thermal expansion in the ferromagnetic region suggest that magneto-volume anomalies, including Invar behaviour, play a major role in the magnetic properties of this system when the crystal structure is face centred cubic. Such behaviour could be explained using theoretical total-band energy calculations.

  4. Research on Materials for High Power Laser Windows

    Science.gov (United States)

    1975-12-01

    1974), "Properties of Hot Forged RbCl-KCl Alloys of Low Rubidium Concentrations", Proceedings of the Fourth Annual Conference on Infrared Laser...0047 2.5 .19 34.8 .4 12.5 244 Cer-VIT C-101 .00004 2.46 .22 77.1 .144 13.4 208 Invar .026 8.00 .095 11.7 1.3 21.4 456 Foam Glass .00014 .14 .20 99.9...8.3 .18 209 ULE Fused Silica .0031 2.16 .18 47.4 .054 9.8 350 Super Invar .033 7.95 .12 9.3 .18 21 49 LA-685 .026 Ŝ.13 .12 10.4 .1 20 29 Graphite

  5. The correct lens mount lightweighting design and thermal stress OPD analysis in Cassegrain telescope

    Science.gov (United States)

    Hsu, Ming-Ying; Chan, Chia-Yen; Lin, Wei-Cheng; Chang, Shenq-Tsong; Huang, Ting-Ming

    2013-09-01

    This study is trying to evaluate different lens barrel material, caused lens stress OPD (Optical Path Different) in different temperature condition. The Cassegrain telescope's correct lens assembly are including as correct lens, lens mount, spacer, mount barrel and retainer. The lens barrel initial design is made by invar, but system mass limit is need to lightweighting to meet requirement. Therefore, the lens barrel material is tried to replace to lower density material, such as aluminum and titanium alloy. Meanwhile, the aluminum or titanium alloy material properties CTE (Coefficient of Thermal Expansion) are larger then invar. Thus, the high CTE material will introduce larger thermal stress into the optical system in different temperature condition. This article is analysis the correct lens assembly thermal stress and optical performance in different lens mount material. From above conditions, using FEM (Finite Element Method) and optical software, simulation and optimization the lens mount to achieve system mass requirement.

  6. Anomalous thermal expansion in iron-nickel alloys: ab initio calculations and the relation to magnetism

    Energy Technology Data Exchange (ETDEWEB)

    Liot, Francois [Department for Computational Materials Design, Max-Planck-Institut fuer Eisenforschung GmbH, 40237 Duesseldorf (Germany); Hooley, Chris [Scottish Universities Physics Alliance (SUPA), School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS (United Kingdom)

    2010-07-01

    The thermal expansion of ferromagnetic disordered iron-nickel alloys at various temperatures is studied, using an approach based on Ising magnetism and first-principles calculations of the disordered local moment (DLM) type. The theory correctly describes the strong increase of the thermal expansion coefficient with increasing nickel concentration from 0.35 to 0.8 at room temperature. It also reproduces the Invar effect for x=0.35. These results are analyzed, and the effect of the magnetic free energy contribution on the thermal expansion is discussed. Furthermore, a simple relationship between anomalous thermal expansion and magnetism is presented. It is argued that an alloy shows the Invar effect if the concentration of nearest-neighbor iron-iron pairs with anti-parallel local moments increases sufficiently rapidly with temperature over a broad temperature interval.

  7. "Distinvar" device

    CERN Multimedia

    CERN PhotoLab

    1965-01-01

    The alignment of one of the accelerator magnets being checked by the AR Division survey group. A "distinvar" device, invented by the group, using calibrated invar wires stretched between the fixed survey pillar (on the left) and a fixed point on the magnet. In two days it is thus possible to measure the alignment of the 100 magnets with an accuracy better than 1/10.

  8. Colloquium on High Resolution Molecular Spectroscopy (8th), 19-23 September 1983 (Colloque sur la Spectroscopie Moleculaire a Haute Resolution (Huitieme), 19-23 Septembre 1983).

    Science.gov (United States)

    1983-09-23

    L’excellente conductibilite thermique de cette structure "Cool Disk TM "permet levwacuation instantanee de la chaleur dissipe~e par la debcharge...orsprmrlsphnmnsdtrts 4I a tete laser comprend une cavite en INVAR compens~e thermiquement assurant une excellente rigidilt% et un bon amortissemnent des...COLLISONAL ELECTRONIC TRANSFERS IN THE 7 Li2 MOLECULE R. Bacis, B. Barakat, S. Churassy (Villeubanne, France) ; R.W. Field, C. Linton, S. McDonald

  9. Building a lunar observatory - An engineer's time table

    Science.gov (United States)

    Chua, Koon Meng; Johnson, Stewart W.; Hicks, Jeffrey D.

    1990-01-01

    This paper shows the feasibility of constructing a 400 ft diameter steerable parabolic radio dish-type observatory on the moon. A structural configuration and the construction procedure are presented. The estimated earth weight of the proposed structure, assuming that graphite-epoxy-invar is used, is about 42 tons. An engineering construction timeline is also presented. The proposed structural configuration of the observatory is shown to be realistic and attainable.

  10. Small-angle neutron scattering in F.C.C. Fe-Ni and Fe-Ni-C alloys

    Energy Technology Data Exchange (ETDEWEB)

    Nadutov, V.M.; Svystunov, Y.O. [G.V. Kurdyumov Inst. for Metal Physics of the N.A.S. of Ukraine, Kyiv (Ukraine); Garamus, V.M.; Willumeit, R. [GKSS Research Centre, Geesthacht (Germany)

    2004-07-01

    Small-angle neutron scattering was studied in Invar Fe-Ni-C alloys in comparison with the Fe-Ni alloy. Moessbauer measurement was carried out to indicate magnetic structure. The nonlinear SANS curves were analysed using a power law function and the Porod approximation and interpreted in terms of aggregates characterized by smooth surfaces or fractal properties. The size and shape of the inhomogeneities were estimated by using the Indirect Fourier Transformation analysis. (orig.)

  11. Moessbauer of phase separation in FeNi multilayers under ion bombardment

    International Nuclear Information System (INIS)

    Amaral, L.; Paesano, A.; Brueckman, M.E.; Shinjo, T.; Ono, T.; Hosoito, N.

    1997-01-01

    We investigated the effect of noble gas irradiation (He, Ne, Ar and Xe) on the Fe-Ni multilayers with a very thin modulation and nominal composition in the invar region Fe 0.63 Ni 0.37 . The evaluation of the formation/stability of the Fe-Ni phases formed under irradiation with different ions and doses was followed by conversion electron Moessbauer spectroscopy (CEMS). (author)

  12. 引抜加工‐時効処理したFe-36wt%Niインバー合金の格子欠陥と,硬さ,熱膨張に及ぼすC,Vの影響

    OpenAIRE

    中間, 一夫; 古谷, 真一; 杉田, 一樹; 井上, 耕治; 白井, 泰治

    2013-01-01

    Fe-36wt%Ni invar alloy has been widely used for precision parts where dimensional changes with temperature are unfavorable. In the viewpoint of industrial application, high-strength with low-thermal-expansion alloys are in increased demand for structural members such as power cables and electronic devices. Additions of alloying elements to and cold working on Fe-Ni alloys are effective methods that enable the alloys to strengthen, although these modifications also influence the magnitude of t...

  13. Precision siting of a particle accelerator

    International Nuclear Information System (INIS)

    Cintra, Jorge Pimentel

    1996-01-01

    Precise location is a specific survey job that involves a high skilled work to avoid unrecoverable results at the project installation. As a function of the different process stages, different specifications can be applied, invoking different instruments: theodolite, measurement tape, distanciometer, invar wire. This paper, based on experience obtained at the installation of particle accelerator equipment, deals with general principles of precise location: tolerance definitions, increasing accuracy techniques, schedule of locations, sensitivity analysis, quality control methods. (author)

  14. Precision siting of a particle accelerator; Locacao de precisao de um acelerador de particulas

    Energy Technology Data Exchange (ETDEWEB)

    Cintra, Jorge Pimentel

    1996-07-01

    Precise location is a specific survey job that involves a high skilled work to avoid unrecoverable results at the project installation. As a function of the different process stages, different specifications can be applied, invoking different instruments: theodolite, measurement tape, distanciometer, invar wire. This paper, based on experience obtained at the installation of particle accelerator equipment, deals with general principles of precise location: tolerance definitions, increasing accuracy techniques, schedule of locations, sensitivity analysis, quality control methods. (author)

  15. Production and Engineering Methods for CARB-TEX (Trade Name) Batteries in Fork Lift Trucks

    Science.gov (United States)

    1974-12-01

    thermal expansion metals compatible with swaging, welding and cost. Possible mater- ials are the Fe-Ni Invar type series or Fe-Co-Ni Kovar alloy . (2...developed. The Carb-TeIPO battery employs a porous carbon -athode, a lithium-aluminum alloy anode, a eutectic mixture of potassium chloride and lithium... alloy of aluminum and lithium. The use of this anode avoids corrosion and other problems associated with operating with liquid lithium anodes. This elec

  16. Summary of the Proceedings of the National Symposium on Fracture Mechanics (17th) Held on 7-9 Aug 84 in Albany, New York.

    Science.gov (United States)

    1986-12-01

    were conducted on both aluminum and tita- nium alloy specimens. Results show that surface crack shapes in solid cylin- ders can be accurately represented...C to 538 0 C to a first order approximation. 1. Soya, H. Takashima, and Y. Tanaka addressed the fatigue behavior of welded Invar sheets in the...into a single flaw. The analysis was confirmed through the use of heat tinting techniques on both Waspalloy and Ti-6246 alloys . 9 W. N. Sharpe, Jr. and J

  17. Determination of the Moessbauer absorption cross section and reconstruction of hyperfine field distribution by the maximum entropy method

    Energy Technology Data Exchange (ETDEWEB)

    Satula, D; Szymanski, K; Dobrzynski, L, E-mail: satula@alpha.uwb.edu.p [Faculty of Physics, University of Bialystok, 41 Lipowa Street, 15-424 Bialystok (Poland)

    2010-07-28

    Determination of the Moessbauer absorption cross section, {sigma}(E), and accurate reconstruction of the hyperfine field distributions of the invar alloy, Fe{sub 64}Ni{sub 36}, by the maximum entropy method (MEM) is presented. The procedure consists of three steps: deconvolution of the Moessbauer spectra with the instrumental resolution function using MEM, nonlinear transformation of the deconvoluted spectrum into {sigma}(E), and reconstruction of the hyperfine field distribution. In order to test the procedure of the deconvolution and correction for thickness effect, several simulated spectra with thickness parameter 1 < t < 50 and different values of Lorentzian FWHM of the source and absorber were analyzed. It is shown that the procedure of the deconvolution and extraction of {sigma}(E) works well for spectra whose lines contain at least five experimental points per FWHM. Reconstructed distributions of hyperfine field parameters, based on the extracted Moessbauer cross section of the Fe-Ni invar alloy, measured with and without application of an external magnetic field, are discussed. The reconstruction has been made to test the earlier postulated non-collinear ferromagnetic state of invar without referring to any specific model in the analysis of the Moessbauer results. It is shown that marginal probability distribution of hyperfine magnetic field consists of the main maximum at about 28 T and a broad tail extending down to 5 T. Observed isomer shift of the main maximum is small and positive. The isomer shift decreases with magnetic field and attains negative values at the lowest fields. It is shown that the magnetic texture parameter does not depend on the hyperfine magnetic field. One thus concludes that in the invar Ni-Fe alloys, in contrast to some theoretical predictions, there is no evidence for different arrangements of the iron magnetic moments as a function of the magnetic hyperfine field.

  18. Rapid Ultrasonic Inspection of Artillery Projectiles.

    Science.gov (United States)

    1978-05-01

    coefficients in four iron-nickel alloys , Armco iron, cold drawn 1018 steel, Invar , and nickel have been in quantitative agreement with the model. 2. On...carbon steels, and at lower carbon contents in alloy steels. If variations in carbon content above that required to produce maximum hardness are...all low carbon steels studied to date (perhaps 10-15 alloys ) comparable efficiencies have been observed except in two cases. 3. In an isothermally

  19. Solid-state-laser-rod holder

    Science.gov (United States)

    Gettemy, D.J.; Barnes, N.P.; Griggs, J.E.

    1981-08-11

    The disclosure relates to a solid state laser rod holder comprising Invar, copper tubing, and epoxy joints. Materials and coefficients of expansion of the components of the holder combine with the rod to produce a joint which will give before the rod itself will. The rod may be lased at about 70 to 80/sup 0/K and returned from such a temperature to room temperature repeatedly without its or the holder's destruction.

  20. Design of an Oxygen Turbopump for a Dual Expander Cycle Rocket Engine

    Science.gov (United States)

    2008-03-01

    circuit. 6 The hydrogen must be heated to temperatures near the design limit for alloys currently used in the chamber liner. Other limits of this...tests (450/800oF) Invar -36 5444 Ignition in all tests (675/340oF) Hastelloy-X 7160 Ignition in all tests (725/750oF) 2.2.2 of the e Bearings

  1. Optimum Filters and Pulsed Signal Storage Devices,

    Science.gov (United States)

    1982-05-05

    but having any value of initial phase, i.e., invar - iant with respect to the initial phase. The property of invariance of an optimum filter is very...22.8 -5.8.10-5 Magnesium Alloys 5.6-5.8 10-20 Steel 4.7-6.1 9-44 4.10-4 Aluminum 5.1-6.4 11.8 -2-10-4 To reduce overall dimensions, solid delay lines

  2. Leadless Chip Carrier Packaging and CAD/CAM-Supported Wire Wrap Interconnect Technology for Subnanosecond ECL.

    Science.gov (United States)

    1981-11-01

    Invar , and alloy 42 in a sandwich configuration. These developments will be monitored by the Mayo group; such a material could provide a substrate with...Points of Various . . . . 124 Solders 4. Composition of Alloys Employed in Dual-In-Line . . . . 128 Package Pins and Plating by Mass Spectrographic...of hardened alloy steel to allow minimum wall thickness; it appeared unlikely that bits with even thinner barrels could be manufactured at acceptable

  3. European Scientific Notes. Volume 35, Number 8,

    Science.gov (United States)

    1981-08-31

    fatigue resistance of the alloys along with their " Invar " (i.e., temperature independent elastic modulus) characteristics; (8) corrosion protection...The laboratory has explored the use of amorphous alloys containing Ti or Zr as brazing foils for joining metals and ceramics. Amorphous foils are...ductile and are easier to work with than conventional alloys in powder or composite form; they are also potentially much cheaper than the Ag-Cu-Ti

  4. Review of High Power Density Superconducting Generators: Present State and Prospects for Incorporating YBCO Windings

    Science.gov (United States)

    2005-01-01

    conductor, the normal component of the magnetic field will be directed away from the HTS con- ductor using magnetic invar rings between the adjacent...small developmental motor/generator, 2004. P.N. Barnes et al. / Cryogenics 45 (2005) 670–686 677 Ag- alloy matrix material. This conductor is made by...a powder metallurgy process, and is readily available as a commercial product. Nevertheless, while it has a higher critical temperature, Tc, this

  5. Strain glass transition in a multifunctional β-type Ti alloy

    Science.gov (United States)

    Wang, Yu; Gao, Jinghui; Wu, Haijun; Yang, Sen; Ding, Xiangdong; Wang, Dong; Ren, Xiaobing; Wang, Yunzhi; Song, Xiaoping; Gao, Jianrong

    2014-02-01

    Recently, a class of multifunctional Ti alloys called GUM metals attracts tremendous attentions for their superior mechanical behaviors (high strength, high ductility and superelasticity) and novel physical properties (Invar effect, Elinvar effect and low modulus). The Invar and Elinvar effects are known to originate from structural or magnetic transitions, but none of these transitions were found in the GUM metals. This challenges our fundamental understanding of their physical properties. In this study, we show that the typical GUM metal Ti-23Nb-0.7Ta-2Zr-1.2O (at%) alloy undergoes a strain glass transition, where martensitic nano-domains are frozen gradually over a broad temperature range by random point defects. These nano-domains develop strong texture after cold rolling, which causes the lattice elongation in the rolling direction associated with the transition upon cooling and leads to its Invar effect. Moreover, its Elinvar effect and low modulus can also be explained by the nano-domain structure of strain glass.

  6. First-principles study of magnetism in Pd3Fe under pressure

    Science.gov (United States)

    Dutta, Biswanath; Bhandary, Sumanta; Ghosh, Subhradip; Sanyal, Biplab

    2012-07-01

    Recent experiments on Pd3Fe intermetallics [M. L. Winterrose , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.102.237202 102, 237202 (2009)] have revealed that the system behaves like a classical invar alloy under high pressure. The experimental pressure-volume relation suggests an anomalous volume collapse and a substantial increase in bulk modulus around the pressure where invar behavior is observed. With the help of first-principles density functional theory based calculations, we have explored various magnetic phases (ferromagnetic, fully and partially disordered local moment, spin spiral) in order to understand the effect of pressure on magnetism. Our calculations reveal that the system does not undergo a transition from a ferromagnetic to a spin-disordered state, as was thought to be the possible mechanism to explain the invar behavior of this system. We rather suggest that the anomaly in the system could possibly be due to the transition from a collinear state to noncollinear magnetic states upon the application of pressure.

  7. Silicon Carbide Mounts for Fabry-Perot Interferometers

    Science.gov (United States)

    Lindemann, Scott

    2011-01-01

    Etalon mounts for tunable Fabry- Perot interferometers can now be fabricated from reaction-bonded silicon carbide structural components. These mounts are rigid, lightweight, and thermally stable. The fabrication of these mounts involves the exploitation of post-casting capabilities that (1) enable creation of monolithic structures having reduced (in comparison with prior such structures) degrees of material inhomogeneity and (2) reduce the need for fastening hardware and accommodations. Such silicon carbide mounts could be used to make lightweight Fabry-Perot interferometers or could be modified for use as general lightweight optical mounts. Heretofore, tunable Fabry-Perot interferometer structures, including mounting hardware, have been made from the low-thermal-expansion material Invar (a nickel/iron alloy) in order to obtain the thermal stability required for spectroscopic applications for which such interferometers are typically designed. However, the high mass density of Invar structures is disadvantageous in applications in which there are requirements to minimize mass. Silicon carbide etalon mounts have been incorporated into a tunable Fabry-Perot interferometer of a prior design that originally called for Invar structural components. The strength, thermal stability, and survivability of the interferometer as thus modified are similar to those of the interferometer as originally designed, but the mass of the modified interferometer is significantly less than the mass of the original version.

  8. Pressure Dependence on the Remanent Magnetization of Fe-Ni Alloys

    Science.gov (United States)

    Gilder, S. A.; Wei, Q.; Maier, B.

    2014-12-01

    We measured the acquisition of magnetic remanence of iron-nickel alloys under pressures up to 23 GPa at room temperature. Experiments on pure iron using different pressure transmission media reveal a higher remanent magnetization at 21.5 GPa than at initial conditions, which could be attributed to a distorted hexagonal closed packed phase grown during the martensitic transition. Upon both compression and decompression, the remanent magnetization of the body centered cubic phases increase several times over initial conditions while the coercivity of remanence remains mostly invariant with pressure. Similar behavior is observed for the face centered cubic phases, where magnetization rises by a factor of 2-3 during compression to the highest applied pressures. Immediately upon decompression, magnetic remanence increases while magnetic coercivity remains fairly constant at relatively low values (5-20 mT). One exception is for the invar composition Fe64Ni36, where magnetization decreases markedly between 5 and 7 GPa. Martensitic effects best explain the increase in remanence rather than grain-size reduction, as the creation of single domain sized grains would raise the coercivity. The magnetic remanence of low Ni invar alloys increases faster with pressure than for other body centered cubic compositions due to the higher magnetostriction of the low Ni invar metals. Thermal demagnetization spectra of Fe64Ni36 measured after pressure cycling broaden as a function of peak pressure, with a systematic decrease in Curie temperature. Irreversible strain accumulation from the martensitic transition likely explains the broadening of the Curie temperature spectra, consistent with our X-ray diffraction analyses.

  9. Boundary-Layer Linear Stability Theory

    Science.gov (United States)

    1984-06-01

    Mailer nultipia aolutiona war» found independently at about tba aaaa tine by Clil (114%, paper presented la 19H) la his study oP •toe- bat» Jeta...59-60. De*«y, A. 1973 A Slapl« suaerioel Method for Solving Orr-Seaaerfeld »rsbleas, Quart. J. M»oh. Appl. Math ., Vol. 26, pp. *C1-*11. Devey, A...Publ., Vol. 17* Foot», J.B. and Lia, CC 1950 3o«e »atwnt Invar» lgatloos in tba Thaory of Hydrodyneala Stability, Quart. Appl. Math ,, foi

  10. Length determination on industrial polymer parts from measurement performed under transient temperature conditions

    DEFF Research Database (Denmark)

    Dalla Costa, Giuseppe; Madruga, Daniel González; De Chiffre, Leonardo

    2016-01-01

    the cooling phase, from 27 °C to 20 °C approximately. The length variation was measured by means of an inductive probe and the temperature with an RTD surface sensor. The frame of the system was composed by elements in Zerodur and Invar to minimize the thermal deformations of the structure. Uniform...... temperature in the part was assumed. The reference length at 20 °C (L20) was calculated with an a posteriori regression of the data from the complete cooling curve. A prediction of L20 was then performed exploiting partial segments of the curve. Several segments with different time spans and starting points...

  11. Phosphorus effect on structure and physical properties of iron-nickel alloys

    International Nuclear Information System (INIS)

    Berseneva, F.N.; Kalinin, V.M.; Rybalko, O.F.

    1982-01-01

    The structure and properties of iron-nickel alloys (30-50 % Ni) containing from 0.02 to 0.5 wt. % P have been investigated. It has been found that phosphorus solubility in iron-nickel alloys at most purified from impurities exceeds limiting solubility values usually observed for commercial alloys. Phosphide eutectics precipitation over the grain boundaries of studied alloys occurs but with phosphorus content equal 0.45 wt. %. The 0.4 wt. % P addition in invar alloys increases saturation magnetization and the Curie point and leads to a more homogeneous structure

  12. Connection between ''exchange'' contribution to elastic modulus and spontaneous magnetostriction

    International Nuclear Information System (INIS)

    Deryabin, A.V.; Kazantsev, V.K.; Shevtsov, B.N.

    1985-01-01

    Transformation of temperature dependences of thermal expansion coefficient, elastic modulus, magnetic and magnetostriction susceptibility is studied at concentration magnetic transitions in quasi-bi nary sections of Fesub(65)Nisub(35-x)Crsub(x), Fesub(50)Nisub(50-x)Mnsub(x), Crsub(10)Fesub(x)Nisub(90-x). It is shown that the ratio between exchange contribution to the elastic modules ΔEsub(A) and a value of spontaneous magnetostriction w sub(m) is not practicall dependent on temperature and composition. Unambiguous relation between ΔEsub(A) and w sub(m) testifies on the unique nature of invar anomaly of thermal expansion and elasticity

  13. High precision survey and alignment techniques in accelerator construction

    CERN Document Server

    Gervaise, J

    1974-01-01

    Basic concepts of precision surveying are briefly reviewed, and an historical account is given of instruments and techniques used during the construction of the Proton Synchrotron (1954-59), the Intersecting Storage Rings (1966-71), and the Super Proton Synchrotron (1971). A nylon wire device, distinvar, invar wire and tape, and recent automation of the gyrotheodolite and distinvar as well as auxiliary equipment (polyurethane jacks, Centipede) are discussed in detail. The paper ends summarizing the present accuracy in accelerator metrology, giving an outlook of possible improvement, and some aspects of staffing for the CERN Survey Group. (0 refs).

  14. Electronic structure of ordered and disordered Fe3Pt

    Science.gov (United States)

    Major, Zs; Dugdale, S. B.; Jarlborg, T.; Bruno, E.; Ginatempo, B.; Staunton, J. B.; Poulter, J.

    2003-06-01

    The electronic structure of invar alloys (i.e. materials in which the near absence of thermal expansion is observed) has been the focus of much study, owing both to the technological applications of these materials and interest in the fundamental mechanism that is responsible for the effect. Here, calculations of the magnetic Compton profiles are presented for ordered and disordered Fe3Pt alloys. Using linear muffin-tin orbital and KKR methods, the latter incorporating the coherent potential approximation to describe the substitutional disorder, the electronic band structure and measurable quantities such as the Fermi surface topology are presented.

  15. Electronic structure of ordered and disordered Fe sub 3 Pt

    CERN Document Server

    Major, Z; Jarlborg, T; Bruno, E; Ginatempo, B; Staunton, J B; Poulter, J

    2003-01-01

    The electronic structure of invar alloys (i.e. materials in which the near absence of thermal expansion is observed) has been the focus of much study, owing both to the technological applications of these materials and interest in the fundamental mechanism that is responsible for the effect. Here, calculations of the magnetic Compton profiles are presented for ordered and disordered Fe sub 3 Pt alloys. Using linear muffin-tin orbital and KKR methods, the latter incorporating the coherent potential approximation to describe the substitutional disorder, the electronic band structure and measurable quantities such as the Fermi surface topology are presented.

  16. Modeling, Simulation, and Analysis of Quantum Transport.

    Science.gov (United States)

    1991-03-15

    either Au-Ge alloying or by will be depleted of carriers. This problem does not arise in Si implantationŜ . The latter is preferable since it creates...also S q2 f~2 E - EF have the contacts defined by Si implantation rather than G 2h’ dE ITo,.(E)I1 sech (2A’T" by Au-Ge alloying . The transmission...disordered medium (i.e., in the ’ique that we adopted. Since the Hamiltonian is time invar - presence of elastic scattering) and hence calculate any time

  17. Deformation-induced dissolution of borides in FCC Fe-Ni alloys

    Science.gov (United States)

    Shabashov, V. A.; Litvinov, A. V.; Lyashkov, K. A.; Kataeva, N. V.; Novikov, S. I.; Titova, S. G.

    2011-12-01

    Deformation-induced dissolution of amorphous and crystal boron and also of orthorhombic boron nitride in face centered cubic (FCC) Fe-Ni alloys matrix has been investigated with the methods of Mössbauer spectroscopy, magnetic susceptibility and X-ray diffraction analysis by compression shear in Bridgman anvils. The formation of boron solid solution in a Fe-Ni alloy matrix has been revealed in the mechanosynthesis process. Growth of inner effective magnetic field, Curie point and crystal lattice period of invar alloys has been detected. Conclusion about the formation of supersaturated crystal boron interstitial solid solution in FCC Fe-Ni alloys has been made.

  18. Crystallization Kinetics of Two Metallic Glasses by Mossbauer Spectroscopy.

    Science.gov (United States)

    1981-03-07

    144 (1977). 4. Fukamichi, K., et al. " Invar -type New Ferromagnetic Amorphous Fe-B Alloys ," Solid State Communications, 23(12): 955-958 (September 1977...of two amorphous iron alloys , Fe 8020 and Fe80 P6 . C 3.5B0* The objectives of this study were: i) to anneal the glasses at various temperatures, 2...nuclei. In this study, it was used to examine the crystallization characteristics of Fe80B20 and Fe8 0 P6 .5C3 . B1 0 amorphous alloys . These materials

  19. Contributions to the International Acoustic Emission Symposium (7th).

    Science.gov (United States)

    1984-09-01

    consistent with Neel’s theory. The temperature dependence data of K for Invar alloys (Fe-36Ni) from various published sources shows considerable...Emission Fe-Ni alloys S 20 ABSTRACT ’Contlrnuo ont reve’rse side It necessary and identify by. bInck n,iIson This report is a collection of three preprints...investigated temperature dependence of MAE behavior of Ni and two Fe-Ni alloys (36% and 471 Ni). Results are generally consistent with expected

  20. Compilative Fe - Ni phase diagram with author's correction

    Science.gov (United States)

    Silman, G. I.

    2012-07-01

    Apart of a complex study of the effect of nickel on structure formation in iron-base alloys is presented. An accurate enough phase diagram for alloys of the Fe - Ni system is still lacking. Compilation of the data of some works and subsequent analysis of the known anomalies of structure and properties in alloys of the system are used by the author for correcting the phase diagram. The corrected diagram is used to explain the special features of Fe - Ni alloys, the well-known "invar" effect in particular.

  1. Multifunctional Alloys Obtained via a Dislocation-Free Plastic Deformation Mechanism.

    Science.gov (United States)

    Saito, Takashi; Furuta, Tadahiko; Hwang, Jung-Hwan; Kuramoto, Shigeru; Nishino, Kazuaki; Suzuki, Nobuaki; Chen, Rong; Yamada, Akira; Ito, Kazuhiko; Seno, Yoshiki; Nonaka, Takamasa; Ikehata, Hideaki; Nagasako, Naoyuki; Iwamoto, Chihiro; Ikuhara, Yuuichi; Sakuma, Taketo

    2003-04-18

    We describe a group of alloys that exhibit "super" properties, such as ultralow elastic modulus, ultrahigh strength, super elasticity, and super plasticity, at room temperature and that show Elinvar and Invar behavior. These "super" properties are attributable to a dislocation-free plastic deformation mechanism. In cold-worked alloys, this mechanism forms elastic strain fields of hierarchical structure that range in size from the nanometer scale to several tens of micrometers. The resultant elastic strain energy leads to a number of enhanced material properties.

  2. Beyond Gaussian approximation in the spin-fluctuation theory of metallic ferromagnetism

    Energy Technology Data Exchange (ETDEWEB)

    Reser, B I; Grebennikov, V I [Institute of Metal Physics, Russian Academy of Sciences, Ekaterinburg (Russian Federation); Melnikov, N B, E-mail: reser@imp.uran.r [Lomonosov Moscow State University, Moscow (Russian Federation)

    2010-01-15

    A characteristic feature of the Gaussian spin-fluctuation theory is the jump transition into the paramagnetic state. We eliminate the jump and obtain a continuous second-order phase transition by taking into account the high-order terms of the free energy of electrons in the fluctuating exchange field. The third-order term of the free energy yields a renormalization of the mean field, and fourth-order term, responsible for the interaction of the fluctuations, gives a renormalization of the spin susceptibility. The extended theory is applied to the calculation of magnetic properties of Fe-Ni Invar.

  3. Noise Abatement and Internal Vibrational Absorption in Potential Structural Materials

    Science.gov (United States)

    1975-03-01

    temperature increasing with the degree of order (]A). This alloy exhibits a large Invar dilation on passing through the Curie temperature. It...idrmilv fcv block numbrr’ Titanium-nickel alloys Vibration damping Sound transmission Internal friction 20 ABSTRACT (Conll nu» on W*WM »irf» II...particular the complete set of resistivity, modulus, heat capacity and damping measurements performed on the 55 w/o Ni-45 w/o Ti alloy shows that over a

  4. Extending the Season for Concrete Construction and Repair. Phase II - Defining Engineering Parameters

    Science.gov (United States)

    2006-04-01

    fabricated from Invar of low thermal expansion, 0.9 × 10–6 de- grees –1. The two LVDTs, Trans-Tek, Series 350, were connected to a data logger, Omnidata...strated with an aluminum alloy (6061-T6) of the same dimensions as the mortar beams. Figure 7 shows the length change-versus-temperature curve for the... alloy . With the exception of minor perturbations caused by the cooling system turning on and off, it can be noted that the aluminum beam contracted

  5. Electronic Manufacturing Process Improvement (EMPI) for Printed Wiring Assemblies

    Science.gov (United States)

    1992-04-01

    of 2-oz/ft2 copper foil were used in the construction of the PWB. The mass of copper selected simulates the thermal characteristics of copper- Invar ...Soldezd LA ewdflwttt (,Tbnmd I-a-d A-afsp Soldered LA• Vobum S ~Solder Babl (Prate Powder Xzirni SolderJdat•epe Taw s Pim /n Figure 4. Infrared Reflow...different lead frame materials. The Diacon package uses alloy 42 in the lead frame while the Kyocera package uses Kovar. These alloys have different

  6. Development of low thermal expansion - high conductivity nanocomposites

    Science.gov (United States)

    Stolk, Jonathan Douglas

    Heat dissipation and thermal expansion mismatch are important issues in many electrical and electronics applications. The thermally induced stresses that arise due to poor thermal management and the thermal expansion mismatch among different board materials can lead to premature failure of electronic assemblies. The solution to the heat dissipation and thermal mismatch problems may lie in the development of low thermal expansion, high conductivity materials. Materials such as Cu-Invar, Cu-Mo, and various metal-ceramic composites have successfully been employed in applications such as heat sinks and core constraining layers in circuit boards, but many of these materials have specific limitations such as high processing costs and anisotropic properties. Homogeneous alloys with intimately mixed components may offer the desired thermal and electrical properties at manufacturing costs much lower than those of the materials currently in use. In addition, homogeneous alloys produced by chemical synthesis and powder processing techniques can offer isotropic thermal, electrical, and mechanical properties, which may be of benefit for future applications where low coefficient of thermal expansion (CTE) and high conductivity are desired. In this dissertation, novel solution-based synthesis techniques aimed at the production of nanocrystalline alloys and composites are explored. Low thermal expansion, high conductivity materials such as Cu-Fe-Ni, Cu-Mo, Ag-Mo and Ag-Fe-Ni are chemically synthesized, processed, and characterized. In most of the systems investigated, homogeneous alloys of a high conductivity phase and a low CTE phase were produced. The Fe and Ni in the Cu-Fe-Ni system combined to form a low CTE Invar-like phase, and CTE values for Cu-Invar alloys ranged from 17.3 x 10 -6°C-1 for pure Cu to 1.85 x 10-6°C-1 for Invar. The electrical and thermal conductivity of the Cu-Fe-Ni alloys, however, was low due to the incorporation of Fe and Ni into the Cu-rich phase

  7. MM&T-Ceramic Metal Substrates for Hybrid Electronics: Handbook

    Science.gov (United States)

    1984-01-01

    Copper EL-P0II-2 Alloy 42 EK5/EK6 303 Stainless Steel Steel- Invar -Steel (a) FERRO-ECA Electronics Company 3130 West 22nd Street, P.O. Box 8305...AND ADDRESS Harry Diamond Laboratories 2800 Powder Mill Road Adelphi, MD 20783 12. REPORT DATE January 1984 13. NUMBER OF PAGES 14...PLASMA-SPRAYED CERAMIC ON METAL Metal Coating Results of Coating Effect of 850oC Thkr Film Profile Alloy #2 105SF 334F LINDE A Good Good

  8. Structural study of the re-entrant spin-glass behaviour of Fe-Al alloys

    Energy Technology Data Exchange (ETDEWEB)

    Martin Rodriguez, D. [Bragg Institute, Australian Nuclear Science and Technology Organisation, PMB 1, Menai NSW 2234 (Australia)]. E-mail: dmr@ansto.gov.au; Plazaola, F. [Elektrika eta Elektronika Saila, UPV-EHU, 644 P.K., 48080 Bilbao (Spain); Garitaonandia, J.S. [Fisika Aplikatua II Saila, UPV-EHU, 644 P.K., 48080 Bilbao (Spain); Cuello, G.J. [Institute Laue Langevin, 6 rue Jules Horowitz, B.P. 156, 38042 Grenoble (France)

    2007-09-15

    Neutron powder diffraction measurements were performed on Fe{sub 70}Al{sub 30} alloy in order to determine the relationship between the magnetic behaviour and the structural changes observed in this alloy. Results show that the re-entrant spin-glass behaviour is linked with D03 structure. There is a strong correlation between the lattice parameter and the diffraction peak intensity and all the magnetic changes reported in literature can be explained in terms of this relationship. Finally, magnetovolume effects similar to invar effect are reported in the spin-glass phase.

  9. Structural study of the re-entrant spin-glass behaviour of Fe-Al alloys

    Science.gov (United States)

    Martín Rodríguez, D.; Plazaola, F.; Garitaonandia, J. S.; Cuello, G. J.

    2007-09-01

    Neutron powder diffraction measurements were performed on Fe 70Al 30 alloy in order to determine the relationship between the magnetic behaviour and the structural changes observed in this alloy. Results show that the re-entrant spin-glass behaviour is linked with D03 structure. There is a strong correlation between the lattice parameter and the diffraction peak intensity and all the magnetic changes reported in literature can be explained in terms of this relationship. Finally, magnetovolume effects similar to invar effect are reported in the spin-glass phase.

  10. Magnetostriction in a simple trivalent manganese perovskite

    Science.gov (United States)

    Hunter, Brett A.; Kennedy, Brendan J.; Vogt, Tom

    2004-01-01

    We found an unusual negative thermal expansion in the simple perovskite MnF3 below the Neel point, where the spins are ordered in an A-type magnetic structure. The structure of MnF3 has been studied between 5 and 500 K using powder neutron and synchrotron diffraction. The structure remains monoclinic C2/c over the entire temperature range. We have found that the interplay of spin and orbital ordering is sufficient to result in a large positive magnetovolume effect without charge ordering. This expansion is reminiscent of the Invar effect observed in certain alloys.

  11. New design proposal for an image slicer prototype: vibration tests and finite element calculations

    Science.gov (United States)

    Rossin, Ch.; Boit, J.-L.; Grassi, E.; Laurent, P.; Martin, L.; Moreaux, G.; Prieto, E.

    2006-06-01

    During the IFU prototype study that the laboratory led for ESA in the frame of the JWST/NIRSpec technological development studies in 2004, an optomechanical concept was realized and tested at the laboratory. As some limitations of this design were demonstrated, the laboratory decided to develop a new concept of optomechanical interface to support glass image slicers, compliant with space environment specifications. This development was conducted in a very short time and with a tiger team. This prototype was designed and realized at LAM. It consists in an invar monolithic mechanical mount (including three blades) supporting an assembly of three zerodur optical parts tight together thanks to optical contact. The interface between invar and zerodur is done with glue. This prototype has been qualified at 10.5 g rms and 77K. It demonstrates the stability of the optical part within +/- 9 arcsec. The test campaign points up the evolution of the glue properties during time and thermal cycles. Thanks to a detailed FEM analysis, the change of the glue material damping has been estimated.

  12. Crystal structure and magnetic properties of the BaFe12−xInxO19 (x=0.1–1.2) solid solutions

    International Nuclear Information System (INIS)

    Trukhanov, S.V.; Trukhanov, A.V.; Turchenko, V.A.; Kostishin, V.G.; Panina, L.V.; Kazakevich, I.S.; Balagurov, A.M.

    2016-01-01

    The investigations of the crystal and magnetic structure by powder neutron diffractometry as well as the magnetic properties by vibration sample magnetometry for the BaFe 12−x In x O 19 (x=0.1–1.2) solid solutions have been performed at different temperatures and magnetic fields. The atomic coordinates and lattice parameters have been Rietveld refined. The Invar effect has been observed in low temperature range (from 150 K to 10 K). It was explained by the thermal oscillation anharmonicity of atoms. The increase of microstress value with decreasing temperature has been defined from Rietveld refinement. The Curie temperature and change of total magnetic moment per formula unit have been defined for all the compositions of the barium hexaferrites BaFe 12−x In x O 19 (x=0.1–1.2) solid solutions. The magnetic structure model is proposed. The most likely reasons and the mechanism of magnetic structure formation are discussed. - Highlights: • Structure and magnetic properties for BaFe 12−x In x O 19 (x=0.1–1.2) are investigated. • Atomic coordinates and lattice parameters Rietveld are refined. • Invar effect is observed below 150 K. • Increase of microstress value with decreasing temperature is defined. • Curie temperature and total magnetic moment per formula unit are defined.

  13. Some ideas on the choice of designs and materials for cooled mirrors

    International Nuclear Information System (INIS)

    Howells, M.R.

    1994-12-01

    This paper expresses some views on the fabrication of future synchrotron beam-line optics; more particularly the metallurgical issues in high-quality metal mirrors. A simple mirror with uniform cooling channels is first analyzed theoretically, followed by the cullular-pin-post system with complex coolant flow path. Choice of mirror material is next considered. For the most challenging situations (need for intensive cooling), the present practice is to use nickel-plated glidcop or silicon; for less severe challenges, Si carbide may be used and cooling may be direct or indirect; and for the mildest heat loads, fused silica or ulf are popular. For the highest performance mirrors (extreme heat load), the glidcop developments should be continued perhaps to cellular-pin-post systems. For extreme distortion, Si is indicated and invar offers both improved performance and lower price. For less extreme challenges but still with cooling, Ni-plated metals have the cost advantage and SXA and other Al alloys can be added to glidcop and invar. For mirrors with mild cooling requirements, stainless steel would have many advantages. Once the internal cooling designs are established, they will be seen as more cost-effective and reliable than clamp-on schemes. Where no cooling is needed, Si, Si carbide, and the glasses can be used. For the future, the effect of electroless Ni layers on cooling design need study, and a way to finish nickel that is compatible with multilayers should be developed

  14. Thermal Expansion Anomaly Regulated by Entropy

    Science.gov (United States)

    Liu, Zi-Kui; Wang, Yi; Shang, Shunli

    2014-11-01

    Thermal expansion, defined as the temperature dependence of volume under constant pressure, is a common phenomenon in nature and originates from anharmonic lattice dynamics. However, it has been poorly understood how thermal expansion can show anomalies such as colossal positive, zero, or negative thermal expansion (CPTE, ZTE, or NTE), especially in quantitative terms. Here we show that changes in configurational entropy due to metastable micro(scopic)states can lead to quantitative prediction of these anomalies. We integrate the Maxwell relation, statistic mechanics, and first-principles calculations to demonstrate that when the entropy is increased by pressure, NTE occurs such as in Invar alloy (Fe3Pt, for example), silicon, ice, and water, and when the entropy is decreased dramatically by pressure, CPTE is expected such as in anti-Invar cerium, ice and water. Our findings provide a theoretic framework to understand and predict a broad range of anomalies in nature in addition to thermal expansion, which may include gigantic electrocaloric and electromechanical responses, anomalously reduced thermal conductivity, and spin distributions.

  15. Analysis of Fe V and Ni V Wavelength Standards in the Vacuum Ultraviolet

    Science.gov (United States)

    Ward, Jacob Wolfgang; Nave, Gillian

    2015-01-01

    The recent publication[1] by J.C. Berengut et al. tests for a potential variation in the fine-structure constant in the presence of high gravitational potentials through spectral analysis of white-dwarf stars.The spectrum of the white-dwarf star studied in the paper, G191-B2B, has prominent Fe V and Ni V lines, which were used to determine any variation in the fine-structure constant via observed shifts in the wavelengths of Fe V and Ni V in the vacuum ultraviolet region. The results of the paper indicate no such variation, but suggest that refined laboratory values for the observed wavelengths could greatly reduce the uncertainty associated with the paper's findings.An investigation of Fe V and Ni V spectra in the vacuum ultraviolet region has been conducted to reduce wavelength uncertainties currently limiting modern astrophysical studies of this nature. The analyzed spectra were produced by a sliding spark light source with electrodes made of invar, an iron nickel alloy, at peak currents of 750-2000 A. The use of invar ensures that systematic errors in the calibration are common to both species. The spectra were recorded with the NIST Normal Incidence Vacuum Spectrograph on phosphor image plate and photographic plate detectors. Calibration was done with a Pt II spectrum produced by a Platinum Neon Hollow Cathode lamp.[1] J. C. Berengut, V. V. Flambaum, A. Ong, et al Phys. Rev. Lett. 111, 010801 (2013)

  16. Development of magnetic moments in Fe{sub 1-x}Ni{sub x} - alloys

    Energy Technology Data Exchange (ETDEWEB)

    Glaubitz, Benjamin; Buschhorn, Stefan; Bruessing, Frank; Zabel, Hartmut [Festkoerperphysik, Ruhr-Universitaet Bochum, 44780 Bochum (Germany)

    2011-07-01

    Fe{sub 1-x}Ni{sub x} alloys have been studied intensively in the past because of their unique properties, such as the soft magnetic properties at x=0.8 and the martensitic bcc-fcc transition at x=0.35. The total magnetic moment as a function of alloy concentration follows by and large the Slater Pauling curve, but not in the region of the martensitic transition, where a strong drop is observed, which has been taken as a sign for strong magneto-volume fluctuations, also known as the invar effect. Using XMCD methods, we have analyzed the individual magnetic moments of Fe and Ni across the alloy concentration range, including their spin and orbital contributions, and we have compared those with the average moments determined by VSM measurements. We find a very good agreement between both methods, with the individual moments showing some fluctuations at the invar concentration but no anomaly. We will discuss the results in the light of recent theoretical predictions.

  17. Pressure dependence on the remanent magnetization of Fe-Ni alloys and Ni metal

    Science.gov (United States)

    Wei, Qingguo; Gilder, Stuart Alan; Maier, Bernd

    2014-10-01

    We measured the acquisition of magnetic remanence of iron-nickel alloys (Fe64Ni36, Fe58Ni42, and Fe50Ni50) and pure Ni under pressures up to 23 GPa at room temperature. Magnetization decreases markedly for Fe64Ni36 between 5 and 7 GPa yet remains ferromagnetic until at least 16 GPa. Magnetization rises by a factor of 2-3 for the other compositions during compression to the highest applied pressures. Immediately upon decompression, magnetic remanence increases for all Fe-Ni alloys while magnetic coercivity remains fairly constant at relatively low values (5-20 mT). The amount of magnetization gained upon complete decompression correlates with the maximum pressure experienced by the sample. Martensitic effects best explain the increase in remanence rather than grain-size reduction, as the creation of single domain sized grains would raise the coercivity. The magnetic remanence of low Ni Invar alloys increases faster with pressure than for other body-centered-cubic compositions due to the higher magnetostriction of the low Ni Invar metals. Thermal demagnetization spectra of Fe64Ni36 measured after pressure release broaden as a function of peak pressure, with a systematic decrease in Curie temperature. Irreversible strain accumulation from the martensitic transition likely explains the broadening of the Curie temperature spectra, consistent with our x-ray diffraction analyses.

  18. Pressure dependence of temperature variation of AC susceptibility for Fe{sub 50}Ni{sub 37}Mn{sub 13} and comparison to Fe{sub 68.1}Ni{sub 31.9}

    Energy Technology Data Exchange (ETDEWEB)

    Matsushita, M. [Department of Mechanical Engineering, Graduate School of Science and Engineering, Ehime University, 3-Bunkyocho, Matsuyama 790-8577 (Japan)], E-mail: matsushita@eng.ehime-u.ac.jp; Ogiyama, H. [Department of Mechanical Engineering, Graduate School of Science and Engineering, Ehime University, 3-Bunkyocho, Matsuyama 790-8577 (Japan); Ono, F. [Okayama University of Science, Okayama 700-0005 (Japan)

    2009-03-15

    Fe{sub 50}Ni{sub 37}Mn{sub 13}, which is a ferromagnetic alloy with FCC crystal structure, has been reported to show the Invar effect below the Curie temperature; however, this alloy shows a typical anti-Invar effect above the Curie temperature. In this paper, we discuss the pressure dependence of the temperature variation of the alternative current (AC) susceptibility at a frequency of 1 kHz for Fe{sub 50}Ni{sub 37}Mn{sub 13} at various pressures up to 7.5 GPa above 77 K; we then compare the results with those for Fe{sub 68.1}Ni{sub 31.9}, which were obtained in a previous study. Fe{sub 50}Ni{sub 37}Mn{sub 13} was in a ferromagnetic state throughout the entire pressure range measured. T{sub C} decreases in inverse proportion to the increasing pressure; dT{sub C}/dp and dln T{sub C}/dp for Fe{sub 50}Ni{sub 37}Mn{sub 13} are -26 K GPa{sup -1} and -0.07 GPa{sup -1}, respectively. Further, the temperature variation of the shape of the {chi}'-T curve for different pressures indicates continuous combining of magnetic interactions occurs at high pressures. These results are similar to those obtained for Fe{sub 68.1}Ni{sub 31.9}.

  19. Elastic wave from fast heavy ion irradiation on solids

    CERN Document Server

    Kambara, T; Kanai, Y; Kojima, T M; Nanai, Y; Yoneda, A; Yamazaki, Y

    2002-01-01

    To study the time-dependent mechanical effects of fast heavy ion irradiations, we have irradiated various solids by a short-bunch beam of 95 MeV/u Ar ions and observed elastic waves generated in the bulk. The irradiated targets were square-shaped plates of poly-crystals of metals (Al and Cu), invar alloy, ceramic (Al sub 2 O sub 3), fused silica (SiO sub 2) and single crystals of KC1 and LiF with a thickness of 10 mm. The beam was incident perpendicular to the surface and all ions were stopped in the target. Two piezo-electric ultrasonic sensors were attached to the surface of the target and detected the elastic waves. The elastic waveforms as well as the time structure and intensity of the beam bunch were recorded for each shot of a beam bunch. The sensor placed opposite to the beam spot recorded a clear waveform of the longitudinal wave across the material, except for the invar and fused silica targets. From its propagation time along with the sound velocity and the thickness of the target, the depth of the...

  20. Progress in developing ultrathin solar cell blanket technology

    Science.gov (United States)

    Patterson, R. E.; Mesch, H. G.; Scott-Monck, J.

    1984-01-01

    A program was conducted to develop technologies for welding interconnects to three types of 50-micron-thick, 2 by 2-cm solar cells. Parallel-gap resistance welding was used for interconnect attachment. Weld schedules were independently developed for each of the three cell types and were coincidentally identical. Six 48-cell modules were assembled with 50-micron (nominal) thick cells, frosted fused-silica covers, silver-plated Invar interconnectors, and four different substrate designs. Three modules (one for each cell type) have single-layer Kapton (50-micron-thick) substrates. The other three modules each have a different substrate (Kapton-Kevlar-Kapton, Kapton-graphite-Kapton, and Kapton-graphite-aluminum honeycomb-graphite). All six modules were subjected to 4112 thermal cycles from -175 to 65 C (corresponding to over 40 years of simulated geosynchronous orbit thermal cycling) and experienced only negligible electrical degradation (1.1 percent average of six 48-cell modules).

  1. Magnetic x-ray linear dichroism of ultrathin Fe-Ni alloy films

    Energy Technology Data Exchange (ETDEWEB)

    Schumann, F.O.; Willis, R.F. [Pennsylvania State Univ., University Park, PA (United States); Goodman, K.W. [Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    The authors have studied the magnetic structure of ultrathin Fe-Ni alloy films as a function of Fe concentration by measuring the linear dichroism of the 3p-core levels in angle-resolved photoemission spectroscopy. The alloy films, grown by molecular-beam epitaxy on Cu(001) surfaces, were fcc and approximately four monolayers thick. The intensity of the Fe dichroism varied with Fe concentration, with larger dichroisms at lower Fe concentrations. The implication of these results to an ultrathin film analogue of the bulk Invar effect in Fe-Ni alloys will be discussed. These measurements were performed at the Spectromicroscopy Facility (Beamline 7.0.1) of the Advanced Light Source.

  2. The influence of humidity on accuracy length measurement on polymer parts

    DEFF Research Database (Denmark)

    Madruga, Daniel González; Alexiou, A.; Dalla Costa, Giuseppe

    2016-01-01

    The work deals with an experimental study of the influence of humidity on accurate length measurements on ABS parts. Polymer parts absorb water from the ambient until they reach hygroscopic equilibrium. Water content causes an expansion of the polymer part. The relationship between the water...... content and this expansion has been barely studied, especially from a metrology point of view including its contribution to the measurement uncertainty. The experimental set-up includes a humidity chamber, an invar fixture with 8 inductive probes and a scale. The humidity chamber was used to create...... parts were measured at 5 levels of relative humidity from 50 %RH to 90 %RH, and constant temperature, 20 ±0.2˚C. Water content equilibrium with the ambient was achieved at each level by acclimatization of the parts for 24 hours. An average length variation over the humidity range of 15 μm was found...

  3. Monolithic I-Beam Crystal Monochromator

    Energy Technology Data Exchange (ETDEWEB)

    Bagnasco, John

    2001-10-16

    Curved crystal, focusing monochromators featuring cubed-root thickness profiles typically employ side-clamped cooling to reduce thermally induced overall bend deformation of the crystal. While performance is improved, residual bend deformation is often an important limiting factor in the monochromator performance. A slightly asymmetric ``I-beam'' crystal cross section with cubed-root flange profiles has been developed to further reduce this effect. Physical motivation, finite-element modeling evaluation and performance characteristics of this design are discussed. Reduction of high mounting stress at the fixed end of the crystal required the soldering of an Invar support fixture to the crystal. Detailed descriptions of this process along with its performance characteristics are also presented.

  4. New insights on the magnetic properties of ferromagnetic FePd3 single-crystals encapsulated inside carbon nanomaterials

    Science.gov (United States)

    Boi, Filippo S.; Du, Yuxuan; Ivaturi, Sameera; He, Yi; Wang, Shanling

    2017-03-01

    FePd3-type alloys have attracted strong interest due to their unusual pressure-induced Invar behaviour characterized by anomalously low thermal expansion properties. However, little is known about the factors controlling their magnetization properties. Here we present a chemical vapour deposition approach which allows the encapsulation of FePd3 alloys into a spherical type of carbon nanomaterial consisting of concentrically arranged distorted-carbon-layers. A dependence of the magnetic properties of this soft ferromagnetic phase on the crystal-grain-size is found by comparing the results in the present study with those reported in literature. The fabricated samples are characterized in detail by electron microscopy, x-ray and electron diffraction and magnetometry.

  5. Automated assembly of Gallium Arsenide and 50-micron thick silicon solar cell modules

    Science.gov (United States)

    Mesch, H. G.

    1984-01-01

    The TRW automated solar array assembly equipment was used for the module assembly of 300 GaAs solar cells and 300 50 micron thick silicon solar cells (2 x 4 cm in size). These cells were interconnected with silver plated Invar tabs by means of welding. The GaAs cells were bonded to Kapton graphite aluminum honeycomb graphite substrates and the thin silicon cells were bonded to 0.002 inch thick single layer Kapton substrates. The GaAs solar cell module assembly resulted in a yield of 86% and the thin cell assembly produced a yield of 46% due to intermittent sticking of weld electrodes during the front cell contact welding operation. (Previously assembled thin cell solar modules produced an overall assembly yield of greater than 80%).

  6. Impact of process parameters and design options on heat leaks of straight cryogenic distribution lines

    Directory of Open Access Journals (Sweden)

    P. Duda

    2017-03-01

    Full Text Available The Future Circular Collider (FCC accelerator will require a helium distribution system that will exceed the presently exploited transfer lines by almost 1 order of magnitude. The helium transfer line will contain five process pipes protected against heat leaks by a common thermal shield. The design pressure of the FCC process pipe with supercritical helium will be equal to 5.0 MPa, significantly exceeding the 2.0 MPa value in the present, state-of–art transfer lines. The increase of the design pressure requires construction changes to be introduced to the support system, the vacuum barriers and the compensation bellows. This will influence heat flows to the helium. The paper analyses the impact of the increased design pressure on the heat flow. The paper also offers a discussion of the design modifications to the compensation system, including the replacement of stainless steel with Invar®—aimed at mitigating the pressure increase.

  7. Development and application of an empirical formula for the high temperature behavior of ferroelectric ceramics switched by electric field at room temperature

    Directory of Open Access Journals (Sweden)

    Dae Won Ji

    2017-05-01

    Full Text Available The strain changes during temperature rise of a poled lead titanate zirconate rectangular parallelepiped switched by electric field at room temperature are obtained by integrating thermal expansion coefficients that are measured using an invar-specimen. By estimating and analyzing pyroelectric and thermal expansion coefficients, first-order differential equations are constructed for polarization and strain changes during temperature increase. The solutions to the differential equations are found and used to calculate the high temperature behavior of the materials. It is shown that the predictions are well compared with measured responses. Finally, the developed formulae are applied to calculate strain butterfly loops from a polarization hysteresis loop at a high temperature.

  8. Development of fully depleted scientific CCDs for astronomy

    Science.gov (United States)

    Boggs, Kasey; Bredthauer, Richard; Lesser, Michael

    2007-02-01

    Due to aggressive scientific specifications, Semiconductor Technology Associates and the University of Arizona's Imaging Technology Laboratory have collaborated to develop a fully depleted back illuminated CCD for scientific imaging. These devices are designed to target increased quantum efficiency into the near-infrared, without reduction in the modulation transfer function, charge transfer efficiency, or rms noise. The STA1700 series imagers are back illuminated 100 micron thick devices with a 10 micron pixel pitch targeted to meet the requirements of the Large Synoptic Survey Telescope (LSST). Recent characterization results will be presented including the point spread function of a 2 micron spot. Also discussed will be the thinning and packaging developments for the STA1700. These efforts include the addition of a backside bias contact, invar package design with high density connectors, as well as etching and backside coating optimization for high resistivity silicon.

  9. The thermal expansion of austenitic manganese and manganese-chromium steels

    International Nuclear Information System (INIS)

    Richter, F.

    1977-01-01

    The linear coefficient of thermal expansion was determined by dilatometer for 5 Mn steels and 6 Mn-Cr steels between -196 and +500 0 C. Because of the antiferromagnetic properties, the thermal expansion of austenitic Mn and Mn-Cr steels is determined by the position of the magnetic changeover temperature (Neel temperature), which depends on the chemical composition of the steel. Below the Neel temperature, the thermal coefficient of expansion is greatly reduced by volumetric magnetostriction (Invar effect). For this reason, one can only give approximate values for thermal expansion for all Mn and Mn-Cr steels in the temperature range of -100 0 C to about +100 0 C. (GSC) [de

  10. Optical substrate materials for synchrotron radiation beamlines

    International Nuclear Information System (INIS)

    Howells, M.R.; Paquin, R.A.

    1997-06-01

    The authors consider the materials choices available for making optical substrates for synchrotron radiation beam lines. They find that currently the optical surfaces can only be polished to the required finish in fused silica and other glasses, silicon, CVD silicon carbide, electroless nickel and 17-4 PH stainless steel. Substrates must therefore be made of one of these materials or of a metal that can be coated with electroless nickel. In the context of material choices for mirrors they explore the issues of dimensional stability, polishing, bending, cooling, and manufacturing strategy. They conclude that metals are best from an engineering and cost standpoint while the ceramics are best from a polishing standpoint. They then give discussions of specific materials as follows: silicon carbide, silicon, electroless nickel, Glidcop trademark, aluminum, precipitation-hardening stainless steel, mild steel, invar and superinvar. Finally they summarize conclusions and propose ideas for further research

  11. Spin-Lattice Coupling and Superconductivity in Fe Pnictides

    Directory of Open Access Journals (Sweden)

    T. Egami

    2010-01-01

    Full Text Available We consider strong spin-lattice and spin-phonon coupling in iron pnictides and discuss its implications on superconductivity. Strong magneto-volume effect in iron compounds has long been known as the Invar effect. Fe pnictides also exhibit this effect, reflected in particular on the dependence of the magnetic moment on the atomic volume of Fe defined by the positions of the nearest neighbor atoms. Through the phenomenological Landau theory, developed on the basis of the calculations by the density functional theory (DFT and the experimental results, we quantify the strength of the spin-lattice interaction as it relates to the Stoner criterion for the onset of magnetism. We suggest that the coupling between electrons and phonons through the spin channel may be sufficiently strong to be an important part of the superconductivity mechanism in Fe pnictides.

  12. Magnetic anisotropy and pressure dependence of the order temperature in the Gd3(FeTi)29 compound

    International Nuclear Information System (INIS)

    Morellon, L.; Arnold, Z.; Pareti, L.; Albertini, F.; Paoluzi, A.

    1995-01-01

    In this work we report ac initial magnetic susceptibility under pressure, singular point detection (SPD) and linear thermal expansion measurements in the Gd 3 (FeTi) 29 intermetallic compound. From these measurements we have determined the anisotropy field, the order temperature and its pressure dependence. The thermal expansion measurement shows an Invar-like anomaly at the order temperature, T C =520 K, which decreases under increasing pressure with a slope of dT C /dp=-2.7 K/kbar. As the Gd 3+ ion is isotropic, no contribution to the anisotropy from the 4f sublattice is expected and low values of the anisotropy fields have been observed. (orig.)

  13. Development of specific materials for the high power electronic components in electric vehicles

    Directory of Open Access Journals (Sweden)

    Kaabi Abderrahmen

    2013-11-01

    Full Text Available The powerchain in electric vehicles sets new demands on semi conductors and their packaging. The latter will be specifically addressed. The power density per cm2 in DC/DC or DC/AC converters requires a mastering of thermomecahnical aspects. The temperature cyling, the environment under the hood of the vehicles and the “hybrid” technology impose severe constraints on the assemblies which may be met by architectured substrates, new options for assemblies and efficient cooling systems. An optimised semi conductor substrate associating copper and invar in a will be developed, relying on roll bonding to produce the 3D architecture. Roll bonding may also be used to associate aluminium and iron to produce light laminates with a CEM performance.

  14. Absolute scale-based imaging position encoder with submicron accuracy

    Science.gov (United States)

    Anisimov, Andrey G.; Pantyushin, Anton V.; Lashmanov, Oleg U.; Vasilev, A. S.; Timofeev, Alexander N.; Korotaev, Valery V.; Gordeev, Sergey V.

    2013-04-01

    Study is devoted to experimental research and development of absolute imaging position encoder based on standard calibrated scale of invar alloy with 1 mm spacing. The encoder uses designed imaging system as a vernier and absolute magnetic encoder as a rough indication. The features of optical design, choice and use of imaging system as long as indexes images processing algorithm are described. A shadow method was implemented: indexes images on a CCD array are formed by the lens focused at the scale surface; the laser module lights up the scale through a beam-splitting prism by a parallel beam. Further dark indexes images on a light scale background are detected and analyzed to estimate the encoder position. Full range of experimental tests was set to calibrate the encoder and to estimate the accuracy. As a result, accuracy close to 1 μm at 1 m was achieved.

  15. Origin of the multiple configurations that drive the response of δ-plutonium’s elastic moduli to temperature

    Science.gov (United States)

    Migliori, Albert; Söderlind, Per; Landa, Alexander; Freibert, Franz J.; Maiorov, Boris; Ramshaw, B. J.; Betts, Jon B.

    2016-01-01

    The electronic and thermodynamic complexity of plutonium has resisted a fundamental understanding for this important elemental metal. A critical test of any theory is the unusual softening of the bulk modulus with increasing temperature, a result that is counterintuitive because no or very little change in the atomic volume is observed upon heating. This unexpected behavior has in the past been attributed to competing but never-observed electronic states with different bonding properties similar to the scenario with magnetic states in Invar alloys. Using the recent observation of plutonium dynamic magnetism, we construct a theory for plutonium that agrees with relevant measurements by using density-functional-theory (DFT) calculations with no free parameters to compute the effect of longitudinal spin fluctuations on the temperature dependence of the bulk moduli in δ-Pu. We show that the softening with temperature can be understood in terms of a continuous distribution of thermally activated spin fluctuations. PMID:27647904

  16. Lattice anharmonicity and thermal properties of strongly correlated Fe1- x Co x Si alloys

    Science.gov (United States)

    Povzner, A. A.; Nogovitsyna, T. A.; Filanovich, A. N.

    2015-10-01

    The temperature dependences of the thermal and elastic properties of strongly correlated metal alloys Fe1- x Co x Si ( x = 0.1, 0.3, 0.5) with different atomic chiralities have been calculated in the framework of the self-consistent thermodynamic model taking into account the influence of lattice anharmonicity. The lattice contributions to the heat capacity and thermal expansion coefficient of the alloys have been determined using the experimental data. It has been demonstrated that the invar effect in the thermal expansion of the lattice observed in the magnetically ordered region of Fe0.7Co0.3Si and Fe0.5Co0.5Si is not related to the lattice anharmonicity, even though its appearance correlates with variations in the atomic chirality.

  17. Effects of spin fluctuations and anomalous thermal expansion of δ-Pu

    Energy Technology Data Exchange (ETDEWEB)

    Solontsov, A.; Antropov, V. P.

    2010-06-02

    We suggest a model for the magnetic dynamics of {delta} plutonium and its alloys in order to show that the dynamical fluctuations of the magnetization density, or spin fluctuations, may be responsible for the anomalies of their observed thermal expansion. We show that due to strong magnetoelastic coupling, spin fluctuations may essentially contribute to the volume strain by giving a negative magnetovolume contribution that is proportional to the squared local magnetic moment and the magnetic Gruneisen constant which is negative in {delta} plutonium. In the presented model, the local magnetic moment increases as the temperature rises, resulting in the interplay between the positive contributions to the volume strain from the lattice and the negative contribution from spin fluctuations, and finally leads to the Invar anomaly or to the negative coefficient of thermal expansion. Our results agree closely with the measured thermal-expansion data for Pu-Ga alloys.

  18. Alignment Stage for a Cryogenic Dilatometer

    Science.gov (United States)

    Dudik, Matthew; Moore, Donald

    2005-01-01

    A three-degree-of-freedom alignment stage has been designed and built for use in a cryogenic dilatometer that is used to measure thermal strains. The alignment stage enables precise adjustments of the positions and orientations of optical components to be used in the measurements and, once adjustments have been completed, keeps the components precisely aligned during cryogenic-dilatometer operations that can last as long as several days. The alignment stage includes a case, a circular tilt/tip platform, and a variety of flexural couplings between the case and the platform, all machined from a single block of the low-thermal-expansion iron/nickel alloy Invar, in order to minimize effects of temperature gradients and to obtain couplings that are free of stiction and friction. There are three sets of flexural couplings clocked at equal angles of 120 degrees around the platform, constituting a three-point kinematic support system.

  19. Consideration of coordinated solar tracking of an array of compact solar-pumped lasers combined with photovoltaic cells for electricity generation

    Science.gov (United States)

    Motohiro, Tomoyoshi; Ichiki, Akihisa; Ichikawa, Tadashi; Ito, Hiroshi; Hasegawa, Kazuo; Mizuno, Shintaro; Ito, Tadashi; Kajino, Tsutomu; Takeda, Yasuhiko; Higuchi, Kazuo

    2015-08-01

    A monochromatic laser light with a photon energy just above the band edge of photovoltaic cells can be converted into electricity with minimal thermal loss. To attain efficient conversion of sunlight to laser light, a coordinated solar tracking system for an array of originally designed compact solar-pumped lasers of 50 mm aperture diameter is being constructed. As for the feasibility of this system, a prototype with a holding capacity of 25 compact solar-pumped lasers has been fabricated. The primary requisite of this system is that the angular accuracy of tracking should be below 1 mrad for all 25 compact solar-pumped lasers to sustain their continuous lasing. To realize this, imperative challenges have been elucidated including thermal expansion under sunlight. A prototype fabricated with its main frame made of Super Invar alloy was found to fulfill the requisite by measurement using a three-dimensional coordinate measuring machine.

  20. Strain Glass as a Novel Multi-functional Material

    Science.gov (United States)

    Wang, Yu; Wang, Dong; Zhou, Yumei; Zhang, Jian; Xue, Dezhen; Ren, Xiaobing

    Strain glass is a frozen disordered state of local lattice strains (nano-martensite domains), which is the third state of the martensitic/ferroelastic system in addition to parent phase and martensite. In this chapter, the key features of strain glass and its multi-functional properties are reviewed. It is shown that strain glass exhibits a number of interesting properties like shape memory effect, superelasticity with narrow hysteresis, tunable damping, together with unusual properties like Invar effect, Elinvar effect as discovered in β-Ti strain glass alloys. All these multi-functional properties stem from the response of the nano-domains of strain glass to temperature change and external stress. With the recent finding of ferromagnetic strain glass, novel magneto-elastic functionalities may be anticipated.

  1. Atomistic Modeling of the Negative Thermal Expansion in δ- Plutonium Based on the Two-State Description.

    Science.gov (United States)

    Lee, Tongsik; Baskes, Michael I; Lawson, A C; Chen, Shao Ping; Valone, Steven M

    2012-06-07

    The δ phase of plutonium with the fcc structure exhibits an unusual negative thermal expansion (NTE) over its narrow temperature range of stability, 593-736 K. An accurate description of the anomalous high-temperature volume effect of plutonium goes beyond the current capability of electronic-structure calculations. We propose an atomistic scheme to model the thermodynamic properties of δ-Pu based on the two-state model of Weiss for the Invar alloys, inspired by the simple free-energy analysis previously conducted by Lawson et al. The two-state mechanism is incorporated into the atomistic description of a many-body interacting system. Two modified embedded atom method potentials are employed to represent the binding energies of two competing electronic states in δ-Pu. We demonstrate how the NTE takes place in δ-Pu by means of Monte Carlo simulations implemented with the two-state mechanism.

  2. Origin of the multiple configurations that drive the response of δ-plutonium's elastic moduli to temperature

    Science.gov (United States)

    Migliori, Albert; Söderlind, Per; Landa, Alexander; Freibert, Franz J.; Maiorov, Boris; Ramshaw, B. J.; Betts, Jon B.

    2016-10-01

    The electronic and thermodynamic complexity of plutonium has resisted a fundamental understanding for this important elemental metal. A critical test of any theory is the unusual softening of the bulk modulus with increasing temperature, a result that is counterintuitive because no or very little change in the atomic volume is observed upon heating. This unexpected behavior has in the past been attributed to competing but never-observed electronic states with different bonding properties similar to the scenario with magnetic states in Invar alloys. Using the recent observation of plutonium dynamic magnetism, we construct a theory for plutonium that agrees with relevant measurements by using density-functional-theory (DFT) calculations with no free parameters to compute the effect of longitudinal spin fluctuations on the temperature dependence of the bulk moduli in δ-Pu. We show that the softening with temperature can be understood in terms of a continuous distribution of thermally activated spin fluctuations.

  3. Pressure effects on the magnetic properties of FeCuZr studied by x-ray magnetic circular dichroism: Evidence of weakening of ferromagnetism in FeCuZr alloys

    Science.gov (United States)

    Martínez, A.; Romero, J. J.; Bartolomé, F.; García, L. M.; Baudelet, F.; Hernando, A.; Crespo, P.

    2012-07-01

    The room temperature changes of the magnetic behavior under pressure of an invar alloy of nominal composition (Fe0.5Cu0.5)87Zr13 (at. %) has been studied by K-edge x-ray magnetic circular dichroism (XMCD) and x-ray absorption near edge spectroscopy (XANES). The Curie temperature, as determined from low field magnetization measurements, is (255 ± 15)K. However XMCD shows a non negligible signal above this temperature. In addition, the XMCD signal decreases upon increasing pressure indicating a pressure-induced collapse of the magnetic moment. These results evidence the itinerant character of FeCuZr alloys as well as the occurrence of magnetovolume effects characterized by a strong dependence of the 3d band on the Fe-Fe nearest neighbor distances.

  4. Extended dynamic spin-fluctuation theory of metallic magnetism

    Energy Technology Data Exchange (ETDEWEB)

    Melnikov, N B [Moscow State University, Moscow 119991 (Russian Federation); Reser, B I; Grebennikov, V I, E-mail: melnikov@cs.msu.su, E-mail: reser@imp.uran.ru, E-mail: greben@imp.uran.ru [Institute of Metal Physics, Ural Branch of the Russian Academy of Sciences, Ekaterinburg 620990 (Russian Federation)

    2011-07-13

    A dynamic spin-fluctuation theory that directly takes into account nonlocality of thermal spin fluctuations and their mode-mode interactions is developed. The Gaussian approximation in the theory is improved by a self-consistent renormalization of the mean field and spin susceptibility due to the third- and fourth-order terms of the free energy, respectively. This eliminates the fictitious first-order phase transition, which is typical for the Gaussian approximation, and yields a proper second-order phase transition. The effect of nonlocal spin correlations is enhanced by taking into account uniform fluctuations in the single-site mean Green function. Explicit computational formulae for basic magnetic characteristics are obtained. The extended theory is applied to the calculation of magnetic properties of Fe-Ni Invar. Almost full agreement with experiment is achieved for the magnetization, Curie temperature, and local and effective magnetic moments.

  5. Optical substrate materials for synchrotron radiation beamlines

    Energy Technology Data Exchange (ETDEWEB)

    Howells, M.R. [Lawrence Berkeley National Lab., CA (United States). Advanced Light Source; Paquin, R.A. [Univ. of Arizona, Tucson, AZ (United States). Optical Sciences Center

    1997-06-01

    The authors consider the materials choices available for making optical substrates for synchrotron radiation beam lines. They find that currently the optical surfaces can only be polished to the required finish in fused silica and other glasses, silicon, CVD silicon carbide, electroless nickel and 17-4 PH stainless steel. Substrates must therefore be made of one of these materials or of a metal that can be coated with electroless nickel. In the context of material choices for mirrors they explore the issues of dimensional stability, polishing, bending, cooling, and manufacturing strategy. They conclude that metals are best from an engineering and cost standpoint while the ceramics are best from a polishing standpoint. They then give discussions of specific materials as follows: silicon carbide, silicon, electroless nickel, Glidcop{trademark}, aluminum, precipitation-hardening stainless steel, mild steel, invar and superinvar. Finally they summarize conclusions and propose ideas for further research.

  6. Thermal-expansion anomalies and spontaneous magnetostriction of Lu{sub 2}Fe{sub 17-x}Si{sub x} intermetallic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Andreev, A.V. [Institute of Physics, Academy of Sciences, Na Slovance 2, Prague 18221 (Czech Republic)], E-mail: andreev@mag.mff.cuni.cz; Danis, S. [Department of Condenced Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, Prague 12116 (Czech Republic)

    2008-07-15

    The thermal expansion of Lu{sub 2}Fe{sub 17-x}Si{sub x} solid solutions has been measured by X-ray powder diffraction. The magnetic ordering in all compounds within the homogeneity range (x{<=}3.4) is accompanied by a large spontaneous volume magnetostriction, distributed anisotropically over the principal axes of the hexagonal crystal structure. The volume effect {omega}{sub s} in the ground state reaches 14.7x10{sup -3} in Lu{sub 2}Fe{sub 17} and decreases monotonously to 8.9x10{sup -3} for x=3.4, following the reduction of magnetic moment. Despite a still large {omega}{sub s}, the Invar behavior observed in Lu{sub 2}Fe{sub 17} changes to a positive thermal expansion for x>1 due to an increasing Curie temperature.

  7. Pellissier H5 hydrostatic level

    CERN Document Server

    Imfeld, H L

    2003-01-01

    Conventional spirit leveling using double scale invar rods has been in use at SLAC for some time as the standard method of obtaining very precise height difference information. Typical accuracy of +- 100 (micro)m and better can routinely be achieved. Procedures and software have evolved to the point where the method is relatively fast and reliable. However, recent projects such as the Final Focus Test Beam have pushed the requested vertical positioning tolerances for alignment of quadrupoles to the 30 mu m level. It is apparent that conventional spirit leveling cannot achieve this level of accuracy. To meet the challenge, the alignment group contracted with Pellissier, Inc. to develop a portable hydrostatic leveling system. The H5 grew out of this development effort and is expected to provide the needed accuracy and ease of use required for such vertical positioning projects. The H5 hydrostatic level is a portable instrument that under ideal operating conditions will provide elevation differences with an accu...

  8. X-ray characteristic temperature of Fe-Ni alloys with different crystal lattices

    International Nuclear Information System (INIS)

    Krasnikova, G.N.; Ushakov, A.I.; Kazakov, V.G.; Bochkarev, V.F.; Gorovoj, A.M.

    1978-01-01

    Investigated has been the temperature dependence of the thermal expansion coefficient and the characteristic Debye temperature of the ferronickel films, having a body-centered (cubic) and a face-centered (cubic) lattice. In case of the body-centered lattice films the tests have been staged in the 100-200 deg C range, and in case of the face c.entered lattice films - in the 20-300 deg C range. The study of temperature dependence of the thermal expansion coefficient has revealed that a non-linear growth of the thermal expansion coefficient occurs in α-phase samples when approaching the phase transition temperature. The phase transition in the Invar composition Fe-Ni films is conductive to a considerable variation of the Debye temperature. Approaching the phase transition temperature, the crystal lattice dynamic characteristics vary

  9. Physics of magnetism and magnetic materials

    CERN Document Server

    Buschow, K H J

    2003-01-01

    In this book, the fundamentals of magnetism are treated, starting at an introductory level. The origin of magnetic moments, the response to an applied magnetic field, and the various interactions giving rise to different types of magnetic ordering in solids are presented and many examples are given. Crystalline-electric-field effects are treated at a level that is sufficient to provide the basic knowledge necessary in understanding the properties of materials in which these effects play a role. Itinerant-electron magnetism is presented on a similar basis. Particular attention has been given to magnetocrystalline magnetic anisotropy and the magnetocaloric effect. Also, the usual techniques for magnetic measurements are presented. About half of the book is devoted to magnetic materials and the properties that make them suitable for numerous applications. The state of the art is presented of permanent magnets, high-density recording materials, soft-magnetic materials, Invar alloys and magnetostrictive materials....

  10. Fabrication of compact electron gun for 6 MeV X-ray source

    International Nuclear Information System (INIS)

    Ghodke, S.R.; Barnwal, Rajesh; Kumar, Mahendra

    2014-01-01

    The 6 MeV X-Ray source for container cargo scanning application has been designed and developed by the Accelerator and Pulse Power Division, BARC, Mumbai. This compact linac has been designed as a mobile system, to be mounted on a moving container. In linac-based cargo-scanning system, to work electron gun on a movable container, it has to be robust. Electron gun is to work at 10 -7 mbar vacuum and 2000 degree Celsius temperature. An effort is made to engineer the gun assembly to make it more robust and aligned. The linac acts as the source of X-rays, which fall on the cargo and are then detected by the detector system. Many components are indigenously developed like grid, insulating ring, Tungsten filament and filament guide, which are made from alumina ceramic and Tantalum which is to work at 1500 degree Celsius. Filament connector is made from Invar to reduce heat loss and to make rigid connection. It was CNC machined and wire cut by EDM. Invar and Copper electrode feed through is shrink fitted with the help of liquid Nitrogen. Shrink fit tolerances of 15 micrometer are achieved by jig boring machining processes. Tantalum cup for LaB6 cathode and heat shield are made from die and punch mechanism. For alignment of electron emitter with beam axis this Tantalum cup is a crucial component. Electron gun is assembled and aligned its components with the help of precision jigs. The whole assembly was Helium leak tested by MSLD up to 4 x 10 -10 mbar.l/s vacuum, no leak was found. This paper will describe the machining, Tantalum cup forming, ceramic components development, heat shields, ceramic feed through etc of electron gun. (author)

  11. Giant negative thermal expansion in magnetic nanocrystals.

    Science.gov (United States)

    Zheng, X G; Kubozono, H; Yamada, H; Kato, K; Ishiwata, Y; Xu, C N

    2008-12-01

    Most solids expand when they are heated, but a property known as negative thermal expansion has been observed in a number of materials, including the oxide ZrW2O8 (ref. 1) and the framework material ZnxCd1-x(CN)2 (refs 2,3). This unusual behaviour can be understood in terms of low-energy phonons, while the colossal values of both positive and negative thermal expansion recently observed in another framework material, Ag3[Co(CN)6], have been explained in terms of the geometric flexibility of its metal-cyanide-metal linkages. Thermal expansion can also be stopped in some magnetic transition metal alloys below their magnetic ordering temperature, a phenomenon known as the Invar effect, and the possibility of exploiting materials with tuneable positive or negative thermal expansion in industrial applications has led to intense interest in both the Invar effect and negative thermal expansion. Here we report the results of thermal expansion experiments on three magnetic nanocrystals-CuO, MnF2 and NiO-and find evidence for negative thermal expansion in both CuO and MnF2 below their magnetic ordering temperatures, but not in NiO. Larger particles of CuO and MnF2 also show prominent magnetostriction (that is, they change shape in response to an applied magnetic field), which results in significantly reduced thermal expansion below their magnetic ordering temperatures; this behaviour is not observed in NiO. We propose that the negative thermal expansion effect in CuO (which is four times larger than that observed in ZrW2O8) and MnF2 is a general property of nanoparticles in which there is strong coupling between magnetism and the crystal lattice.

  12. Magnetostriction and thermal expansion of HoFe11-xCoxTi intermetallic compounds

    Science.gov (United States)

    Sanavi Khoshnoud, D.; Tajabor, N.; Motevalizadeh, L.; Fruchart, D.

    2014-08-01

    The thermal expansion and magnetostriction of the HoFe11-xCoxTi (0≤x≤11) alloys have been investigated, using the strain gauge technique in the temperature range 77-600 K. Both thermal expansion and thermal expansion coefficient exhibit an anomalous behaviour and Invar effect below Curie temperature (TC=516 K) in sample with x=0. The increase of x in HoFe11-xCoxTi system leads to disappearing of the Invar effect and increasing of the average thermal expansion coefficient from 6.370×10-6 K-1 in x=0 to 10.735×10-6 K-1 in x=11 below room temperature. In addition, the spontaneous volume magnetostriction decreases with Co content. The magnetostriction compensation point is observed in the anisotropic magnetostriction curve of all samples. The maximum value of anisotropic magnetostriction (Δλ≈50×10-6) at room temperature is observed in sample with x=9. The saturation behaviour only appears in samples with x=5, 7 and 9. In samples with x=3, 5 and 7, a noticeable volume magnetostriction (ΔV/V) is observed in low temperature due to first-order magnetisation process. Moreover, ΔV/V exhibits a large anomaly about 45×10-6 and 20×10-6 around room temperature related to spin reorientation transition in samples with x=9 and 11, respectively. The results are discussed based on the local magnetic moment model and irreducible magnetoelastic coupling modes.

  13. Magnetostriction and thermal expansion of HoFe{sub 11−x}Co{sub x}Ti intermetallic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Sanavi Khoshnoud, D., E-mail: dskhoshnoud@profs.semnan.ac.ir [Department of Physics, Semnan University, Semnan 35195-363 (Iran, Islamic Republic of); Tajabor, N. [Department of Physics, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of); Motevalizadeh, L. [Department of Physics, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of); Fruchart, D. [Institut. Néel, Département MCMF, Groupe IICF, BP 166, 38042 Grenoble Cedex 9 (France)

    2014-08-01

    The thermal expansion and magnetostriction of the HoFe{sub 11−x}Co{sub x}Ti (0≤x≤11) alloys have been investigated, using the strain gauge technique in the temperature range 77–600 K. Both thermal expansion and thermal expansion coefficient exhibit an anomalous behaviour and Invar effect below Curie temperature (T{sub C}=516 K) in sample with x=0. The increase of x in HoFe{sub 11−x}Co{sub x}Ti system leads to disappearing of the Invar effect and increasing of the average thermal expansion coefficient from 6.370×10{sup −6} K{sup −1} in x=0 to 10.735×10{sup −6} K{sup −1} in x=11 below room temperature. In addition, the spontaneous volume magnetostriction decreases with Co content. The magnetostriction compensation point is observed in the anisotropic magnetostriction curve of all samples. The maximum value of anisotropic magnetostriction (Δλ≈50×10{sup −6}) at room temperature is observed in sample with x=9. The saturation behaviour only appears in samples with x=5, 7 and 9. In samples with x=3, 5 and 7, a noticeable volume magnetostriction (ΔV/V) is observed in low temperature due to first-order magnetisation process. Moreover, ΔV/V exhibits a large anomaly about 45×10{sup −6} and 20×10{sup −6} around room temperature related to spin reorientation transition in samples with x=9 and 11, respectively. The results are discussed based on the local magnetic moment model and irreducible magnetoelastic coupling modes. - Highlights: • Magnetoelastic properties of HoFe{sub 11−x}Co{sub x}Ti (x=0–11) compounds is investigated. • Thermal expansion coefficient values increase with Co substitution. • The maximum value of anisotropic magnetostriction at room temperature is observed in x=9. • A considerable volume effect is exhibited in low temperatures due to FOMP in samples with x=3, 5 and 7, and due to SRT in samples x=9 and 11 around room temperature.

  14. Miniature Piezoelectric Shaker for Distribution of Unconsolidated Samples to Instrument Cells

    Science.gov (United States)

    Sherrit, Stewart; Tucker, Curtis E. Jr.; Frankovich, John; Bao, Xiaoqi

    2010-01-01

    The planned Mars Science Laboratory mission requires inlet funnels for channeling unconsolidated powdered samples from the sampling and sieving mechanisms into instrument test cells, which are required to reduce cross-contamination of the samples and to minimize residue left in the funnels after each sample transport. To these ends, a solid-state shaking mechanism has been created that requires low power and is lightweight, but is sturdy enough to survive launch vibration. The funnel mechanism is driven by asymmetrically mounted, piezoelectric flexure actuators that are out of the load path so that they do not support the funnel mass. Each actuator is a titanium, flextensional piezoelectric device driven by a piezoelectric stack. The stack has Invar endcaps with a half-spherical recess. The Invar is used to counteract the change in stress as the actuators are cooled to Mars ambient temperatures. A ball screw is threaded through the actuator frame into the recess to apply pre-stress, and to trap the piezoelectric stack and endcaps in flexure. During the vibration cycle of the flextensional actuator frame, the compression in the piezoelectric stack may decrease to the point that it is unstressed; however, because the ball joint cannot pull, tension in the piezoelectric stack cannot be produced. The actuators are offset at 120 . In this flight design, redundancy is required, so three actuators are used though only one is needed to assist in the movement. The funnel is supported at three contact points offset to the hexapod support contacts. The actuator surface that does not contact the ring is free to expand. Two other configurations can be used to mechanically tune the vibration. The free end can be designed to drive a fixed mass, or can be used to drive a free mass to excite impacts (see figure). Tests on this funnel mechanism show a high density of resonance modes between 1 and 20 kHz. A subset of these between 9 and 12 kHz was used to drive the CheMin actuators

  15. Hyperfine interactions and some thermomagnetic properties of amorphous FeZr(CrNbBCu alloys

    Directory of Open Access Journals (Sweden)

    Łukiewska Agnieszka

    2017-06-01

    Full Text Available In this research, we studied the magnetic phase transition by Mössbauer spectroscopy and using vibrating sample magnetometer for amorphous Fe86-xZr7CrxNb2Cu1B4 (x = 0 or 6 alloys in the as-quenched state and after accumulative annealing in the temperature range 600-750 K. The Mössbauer investigations were carried out at room and nitrogen temperatures. The Mössbauer spectra of the investigated alloys at room temperature are characteristic of amorphous paramagnets and have a form of asymmetric doublets. However, at nitrogen temperature, the alloys behave like ferromagnetic amorphous materials. The two components are distinguished in the spectrum recorded at both room and nitrogen temperatures. The low field component in the distribution of hyperfine field induction shifts towards higher field with the annealing temperature. It is assumed that during annealing at higher temperature, due to diffusion processes, the grains of α-Fe are created in the area corresponding to this component. Both investigated alloys show the invar effect and the decrease of hyperfine field induction after annealing at 600 K for 10 min is observed. It is accompanied by the lowering of Curie temperature.

  16. Effect of soil-spraying time on root-colonization ability of antagonistic Streptomyces griseoviridis

    Directory of Open Access Journals (Sweden)

    H. KORTEMAA

    2008-12-01

    Full Text Available The root-colonization ability of Streptomyces griseoviridis Anderson et al. was tested on turnip rape (Brassica rapa subsp. oleifera DC. and carrot (Daucus carota L. by the sand-tube method. Non-sterile sand was sprayed with a microbial suspension immediately or 7 days after the seed had been sown. Results expressed as population frequencies and densities indicated that S. griseoviridis effectively colonizes the rhizosphere when the microbe is applied immediately after sowing but less effectively when it is applied 7 days later. Detection values of S. griseoviridis were higher for turnip rape than for carrot. In sterile sand, S. griseoviridis invaribly colonized the rhizosphere of turnip rape after each of the two applications. These findings indicate that S. griseoviridis can compete with indigenous soil microbes in the rhizosphere if it is sufficiently abundant in the soil before the seed emerges. If applied later, however, it competes rather poorly. In root-free nonsterile sand, S. griseoviridis dispersed and survived well.;

  17. Development of a high power HCN waveguide laser for plasma diagnostic

    International Nuclear Information System (INIS)

    Deng Zhongchao; Zhou Yan; Tang Yiwu; Yi Jiang; Gao Bingyi; Tian Chongli

    2007-06-01

    Both design and development of a high power cw HCN waveguide laser is described for multichannel FIR laser interferometer on the HL-2A divertor tokamak. The geometry parameters of stracture of the HCN laser are calculated according to scaling laws for cw 337 μm HCN waveguide laser offered by P. Belland et al. The designed value of output power of the laser that is more than 400 mW with discharge length of 5.6 m and 6.3 cm inner diameter of tube have been chosen in case of external loss of the cavity of 2%. At the same time, in order to get a laser system of stable output both of configuration and operating condition is discussed. In developed laser a hot LaB 6 cathode is employed to en- sure a stable discharge, the cavity mirrors are spaced using four invar rod of φ25 mm in diameter and an structure of adjusting machine for axially movable flat mirror in cavity has been also designed, and that it can be taken down many times without badly destroying alignment of the cavity etc.. A suit of pipes sys- tem of cw HCN laser is schemed out so that some experiments of operating parameter optimization can be done. The results of primary test of operating waveguide HCN laser are briefly showed. (authors)

  18. Weldability of an iron meteorite by Friction Stir Spot Welding: A contribution to in-space manufacturing

    Science.gov (United States)

    Evans, William Todd; Neely, Kelsay E.; Strauss, Alvin M.; Cook, George E.

    2017-11-01

    Friction Stir Welding has been proposed as an efficient and appropriate method for in space welding. It has the potential to serve as a viable option for assembling large scale space structures. These large structures will require the use of natural in space materials such as those available from iron meteorites. Impurities present in most iron meteorites limit its ability to be welded by other space welding techniques such as electron beam laser welding. This study investigates the ability to weld pieces of in situ Campo del Cielo meteorites by Friction Stir Spot Welding. Due to the rarity of the material, low carbon steel was used as a model material to determine welding parameters. Welded samples of low carbon steel, invar, and Campo del Cielo meteorite were compared and found to behave in similar ways. This study shows that meteorites can be Friction Stir Spot Welded and that they exhibit properties analogous to that of FSSW low carbon steel welds. Thus, iron meteorites can be regarded as another viable option for in-space or Martian construction.

  19. Vibration-Assisted Femtosecond Laser Drilling with Controllable Taper Angles for AMOLED Fine Metal Mask Fabrication

    Directory of Open Access Journals (Sweden)

    Wonsuk Choi

    2017-02-01

    Full Text Available This study investigates the effect of focal plane variation using vibration in a femtosecond laser hole drilling process on Invar alloy fabrication quality for the production of fine metal masks (FMMs. FMMs are used in the red, green, blue (RGB evaporation process in Active Matrix Organic Light-Emitting Diode (AMOLED manufacturing. The taper angle of the hole is adjusted by attaching the objective lens to a micro-vibrator and continuously changing the focal plane position. Eight laser pulses were used to examine how the hole characteristics vary with the first focal plane’s position, where the first pulse is focused at an initial position and the focal planes of subsequent pulses move downward. The results showed that the hole taper angle can be controlled by varying the amplitude of the continuously operating vibrator during femtosecond laser hole machining. The taper angles were changed between 31.8° and 43.9° by adjusting the vibrator amplitude at a frequency of 100 Hz. Femtosecond laser hole drilling with controllable taper angles is expected to be used in the precision micro-machining of various smart devices.

  20. The James Webb Space Telescope

    Science.gov (United States)

    Nowak, Maria; Eichorn, William; Hill, Michael; Hylan, Jason; Marsh, James; Ohl, Raymond; Sampler, Henry; Wright, Geraldine; Crane, Allen; Herrera, Acey; hide

    2007-01-01

    The James Webb Space Telescope (JWST) is a 6.6m diameter, segmented, deployable telescope for cryogenic IR space astronomy (approx.40K). The JWST Observatory architecture includes the Optical Telescope Element and the Integrated Science Instrument Module (ISIM) element that contains four science instruments (SI) including a Guider. The ISIM optical metering structure is a roughly 2.2x1.7x2.2mY, asymmetric frame that is composed of carbon fiber and resin tubes bonded to invar end fittings and composite gussets and clips. The structure supports the SIs, isolates the SIs from the OTE, and supports thermal and electrical subsystems. The structure is attached to the OTE structure via strut-like kinematic mounts. The ISM structure must meet its requirements at the approx.40K cryogenic operating temperature. The SIs are aligned to the structure s coordinate system under ambient, clean room conditions using laser tracker and theodolite metrology. The ISM structure is thermally cycled for stress relief and in order to measure temperature-induced mechanical, structural changes. These ambient-to-cryogenic changes in the alignment of SI and OTE-related interfaces are an important component in the JWST Observatory alignment plan and must be verified.

  1. Mechanical design and qualification of IR filter mounts and filter wheel of INSAT-3D sounder for low temperature

    Science.gov (United States)

    Vora, A. P.; Rami, J. B.; Hait, A. K.; Dewan, C. P.; Subrahmanyam, D.; Kirankumar, A. S.

    2017-11-01

    Next generation Indian Meteorological Satellite will carry Sounder instrument having subsystem of filter wheel measuring Ø260mm and carrying 18 filters arranged in three concentric rings. These filters made from Germanium, are used to separate spectral channels in IR band. Filter wheel is required to be cooled to 214K and rotated at 600 rpm. This Paper discusses the challenges faced in mechanical design of the filter wheel, mainly filter mount design to protect brittle germanium filters from failure under stresses due to very low temperature, compactness of the wheel and casings for improved thermal efficiency, survival under vibration loads and material selection to keep it lighter in weight. Properties of Titanium, Kovar, Invar and Aluminium materials are considered for design. The mount has been designed to accommodate both thermal and dynamic loadings without introducing significant aberrations into the optics or incurring permanent alignment shifts. Detailed finite element analysis of mounts was carried out for stress verification. Results of the qualification tests are discussed for given temperature range of 100K and vibration loads of 12g in Sine and 11.8grms in Random at mount level. Results of the filter wheel qualification as mounted in Electro Optics Module (EOM) are also presented.

  2. Optical bi-stable shutter development/improvement

    Science.gov (United States)

    Lizon, J. L.; Haddad, N.; Castillo, R.

    2012-09-01

    Two of the VLT instruments (Giraffe and VIMOS) are using the large magnetic E/150 from Prontor (with an aperture diameter of 150 mm). As we were facing an unacceptable number of failures with this component some improvement plan was discussed already in 2004. The final decision for starting this program was conditioned by the decision from the constructor to stop the production. The opportunity was taken to improve the design building a fully bi-stable mechanism in order to reduce the thermal dissipation. The project was developed in collaboration between the two main ESO sites doing the best use of the manpower and of the technical capability available at the two centers. The project took advantage of the laser Mask Manufacturing Unit and the invar sheets used to prepare the VIMOS MOS mask to fabricate the shutter petals. Our paper describes the development including the intensive and long optimization period. To conclude this optimization we proceed with a long life test on two units. These units have demonstrate a very high level of reliability (up to 100 000 cycles without failure which can be estimated to an equivalent 6 years of operation of the instrument) A new bi-stable shutter driver and controller have also been developed. Some of the highlights of this unit are the fully configurable coil driving parameters, usage of braking strategy to dump mechanical vibration and reduce mechanical wearing, configurable usage of OPEN and CLOSE sensors, non volatile storage of parameters, user friendly front panel interface.

  3. Multiple small-angle neutron scattering for an arbitrary value of the Born parameter

    International Nuclear Information System (INIS)

    Bogdanov, S.G.; Men'shikov, A. Z.

    2000-01-01

    Computer calculations are made of the intensity of multiple small-angle neutron scattering using the general Moliere formula over a wide range of variation of the Born parameter, embracing the diffraction and refraction regimes, and a transition region between diffraction and reflection. A comparison is made with approximate formulas obtained earlier by Maleev et al. in the limiting cases of the Born parameter α > 1 for the diffraction and refraction regimes, respectively. It is shown that over a wide range of values of α the results of the calculations using the approximate and general formulas are the same. The theoretical conclusions were checked experimentally using data from measurements of small-angle neutron scattering for the domain structure of ferromagnets. Measurements were made of the neutron beam broadening for samples of different thickness and these were used to determine the effective domain sizes in pure iron and nickel exposed to thermal treatment and plastic deformation, and also in the Invar alloys Fe 65 Ni 35 and Fe 3 Pt. An analysis is made of the angular dependence of magnetic small-angle neutron scattering at the asymptote

  4. Slow neutron scattering with small angle. 5-6

    International Nuclear Information System (INIS)

    Komura, Shigehiro

    1976-01-01

    The principle, experimental apparatus, and applications of small angle neutron scattering are briefly reviewed. As for the principle, the mathematical expressions for the nuclear and magnetic scattering cross sections of neutrons are given. The advantages of utilizing cold neutrons are also discussed. As for the experimental apparatus, the one at ILL, Grenoble, is introduced with a bird-eye view, a schematic diagram, and the fundamental parameters of the apparatus. The calculated and measured spectra of neutron flux at the exit of a guide tube are also presented. The first example of the small angle neutron scattering is the measurement of void distribution within aluminum single-crystals irradiated with fast neutrons, which was carried out at Juelich. The second problem is the magnetic unevenness in the single crystal of Fe-Ni invar alloy. The third application is the observation of the helical structure of the tobacco mosaic virus in D 2 O. It is suggested that significant informations are expected to be obtained about the conformation of RNA in virus from the results of this observation. (Aoki, K.)

  5. Quantum-Well Infrared Photodetector (QWIP) Focal Plane Assembly

    Science.gov (United States)

    Jhabvala, Murzy; Jhabvala, Christine A.; Ewin, Audrey J.; Hess, Larry A.; Hartmann, Thomas M.; La, Anh T.

    2012-01-01

    A paper describes the Thermal Infrared Sensor (TIRS), a QWIP-based instrument intended to supplement the Operational Land Imager (OLI) for the Landsat Data Continuity Mission (LDCM). The TIRS instrument is a far-infrared imager operating in the pushbroom mode with two IR channels: 10.8 and 12 microns. The focal plane will contain three 640x512 QWIP arrays mounted on a silicon substrate. The silicon substrate is a custom-fabricated carrier board with a single layer of aluminum interconnects. The general fabrication process starts with a 4-in. (approx.10-cm) diameter silicon wafer. The wafer is oxidized, a single substrate contact is etched, and aluminum is deposited, patterned, and alloyed. This technology development is aimed at incorporating three large-format infrared detecting arrays based on GaAs QWIP technology onto a common focal plane with precision alignment of all three arrays. This focal plane must survive the rigors of flight qualification and operate at a temperature of 43 K (-230 C) for five years while orbiting the Earth. The challenges presented include ensuring thermal compatibility among all the components, designing and building a compact, somewhat modular system and ensuring alignment to very tight levels. The multi-array focal plane integrated onto a single silicon substrate is a new application of both QWIP array development and silicon wafer scale integration. The Invar-based assembly has been tested to ensure thermal reliability.

  6. Thermal expansion and transformation behavior of cerium and plutonium alloys: an application of the Aptekar-Ponyatovsky regular solution model.

    Science.gov (United States)

    Lawson, A C; Lashley, J C

    2011-09-14

    In this paper we apply the Aptekar-Ponyatovsky (AP) regular solution thermodynamic model to the analysis of experimental data for the coefficient of thermal expansion (CTE) and determine the AP model parameters for unalloyed cerium metal, Ce-Th-La alloys, and Pu-Ga alloys. We find that the high temperature CTE of cerium metal follows the predictions of the AP model based on low temperature, high pressure data. For Ce-Th-La alloys we use the AP parameters to track the suppression of the first-order γ-α cerium transition. We show the AP model accounts for the negative CTE observed for Pu-Ga alloys and is equivalent to an earlier invar model. Finally, we apply the AP parameters obtained for Pu-Ga alloys to rationalize the observed δ-α transformation pressures of these alloys. We show that the anomalous values of the Grüneisen and Grüneisen-Anderson parameters are important features of the thermal properties of plutonium. A strong analogy between the properties of plutonium and cerium is confirmed.

  7. Jean Gervaise 1921 -2007

    CERN Multimedia

    2007-01-01

    Jean Gervaise, a pioneer of metrology at CERN, passed away on 10 April. A French geodesist, he was behind the creation and development of CERN's metrology group and was a consistently fervent advocate of innovation to meet the increasingly demanding alignment needs of the accelerators and detectors. Under his leadership, metrology at CERN acquired international renown. Jean Gervaise taking measurements with invar wire and a theodolite on a pillar at the PS. In spite of the disruptions caused by the second world war, Jean Gervaise was able to complete an engineering degree at the Ecole nationale des Sciences géographiques in Paris, which led to a first job in the prestigious Geodesy Department of the Institut géographique national (IGN). This 'queen of disciplines', as he called it, is the most scientific and most complex of the branches of cartography, offering opportunities for exciting and varied - sometimes highly adventurous - missions at home and abroad. The rich experience he acquired here helped to...

  8. Modifications to improve entrance slit thermal stability for grasshopper monochromators

    Science.gov (United States)

    Wallace, Daniel J.; Rogers, Gregory C.; Crossley, Sherry L.

    1994-08-01

    As new monochromators are designed for high-flux storage rings, computer modeling and thermal engineering can be done to process increased heat loads and achieve mechanical stability. Several older monochromators, such as the Mark 2 and Mark 5 Grasshopper monochromators, which were designed in 1974, have thermal instabilities in their entrance slit mechanisms. The Grasshoppers operating with narrow slits experience closure of the entrance slit from thermal expansion. In extreme cases, the thermal expansion of the precision components has caused permanent mechanical damage, leaving the slit uncalibrated and/or inoperable. For the Mark 2 and Mark 5 Grasshopper monochromators at the Synchrotron Radiation Center, the original 440 stainless steel entrance slit jaws were retrofitted with an Invar (low expansion Fe, Ni alloy) slit jaw. To transfer the heat from the critical components, two flexible heat straps of Cu were attached. These changes allow safe operation with a 10 μm entrance slit width where the previous limit was 30 μm. After an initial 2 min equilibration, the slit remains stable to 10%, with 100 mA of beam current. Additional improvements in slit thermal stability are planned for a third Grasshopper.

  9. Engineering stress in thin films for the field of bistable MEMS

    Science.gov (United States)

    Ratnayake, Dilan; Martin, Michael D.; Gowrishetty, Usha R.; Porter, Daniel A.; Berfield, Thomas A.; McNamara, Shamus P.; Walsh, Kevin M.

    2015-12-01

    While stress-free and tensile films are well-suited for released in-plane MEMS designs, compressive films are needed for released out-of-plane MEMS structures such as buckled beams and diaphragms. This study presents a characterization of stress on a variety of sputtered and plasma-enhanced chemical vapour deposition (PECVD)-deposited films, including titanium tungsten, invar, silicon nitride and amorphous silicon, appropriate for the field of bistable MEMS. Techniques and strategies are presented (including varying substrate bias, pressure, temperature, and frequency multiplexing) for tuning internal stress across the spectrum from highly compressive (-2300 MPa) to highly tensile (1500 MPa). Conditions for obtaining stress-free films are also presented in this work. Under certain conditions during the PECVD deposition of amorphous silicon, interesting ‘micro-bubbles’ formed within the deposited films. Strategies to mitigate their formation are presented, resulting in a dramatic improvement in surface roughness quality from 667 nm root mean square (RMS) to 16 nm RMS. All final deposited films successfully passed the traditional ‘tape test’ for adhesion.

  10. Influence of low Co substitution on magnetoelastic properties of HoFe11Ti intermetallic compound

    International Nuclear Information System (INIS)

    Motevalizadeh, L.; Tajabor, N.; Sanavi Khoshnoud, D.; Fruchart, D.; Pourarian, F.

    2012-01-01

    The thermal expansion and magnetostriction of HoFe 11−x Co x Ti (x=0, 0.3, 0.7 and 1) intermetallic compounds were measured, using the strain gauge method in the temperature range 77–590 K under applied magnetic fields up to 1.5 T. Results show that for samples with x=0 and 0.3, both linear thermal expansion and linear thermal expansion coefficient exhibit anomalies below the Curie temperature. Below room temperature, the spontaneous volume magnetostriction decreases with Co content. For all compounds studied, the anisotropic magnetostriction shows similar behaviour in the measured temperature range. The magnetostriction compensation occurs above room temperature in all samples. The volume magnetostriction shows a linear dependence on the applied field and by approaching the Curie temperature this trend changes to parastrictive behaviour. The results of the spontaneous magnetostriction are discussed based on the local magnetic moment model. The contribution of magnetostriction attributed to the magnetic sublattices R and T (Fe or Co) is discussed. - Highlights: ► Magnetostriction of HoFe 11−x Co x Ti have been measured by using strain gauge method. ► The measurement was carried in 77–590 K under applied magnetic fields up to 1.5 T. ► Spontaneous volume magnetostriction and Invar effect decrease with Co substitution. ► Ho sublattice has negative contribution to spontaneous volume magnetostriction. ► Absolute values of anisotropic magnetostriction decrease slightly with Co content.

  11. The design of an optical sensor arrangement for the detection of oil contamination in an adhesively bonded structure of a liquefied natural gas (LNG) ship

    International Nuclear Information System (INIS)

    Kim, Bu Gi; Lee, Dai Gil

    2009-01-01

    Liquefied natural gas (LNG) has been widely used as a substitute fuel for commercial purposes. It is transported mainly by LNG ships which have primary and secondary leakage barriers. The former is composed of welded thin stainless steel or invar plates, while the latter is composed of adhesively bonded glass composite or aluminum foil sheets. The role of the secondary barrier is to maintain fluid tightness when the primary barrier fails during the transport of LNG. The tightness of the secondary barrier is dependent on the wetting characteristics between the adhesive and adherend of the bonded structure during bonding operation, which depends much on the contamination on the adherend surface. Therefore, in this work, an optical measuring device of oil contamination on the aluminum surface for the secondary barrier was developed. A transparent oil was used as the contaminant and its effect on the bonding strength was investigated. From the experiments, it has been found that the developed measuring device for oil contamination can be used to detect oil contamination on a large bonding area of the secondary barrier in ship building yards

  12. Thermal stress failure criteria for a structural epoxy

    Science.gov (United States)

    Côté, Patrice; Desnoyers, Nichola

    2011-09-01

    Representative failure data for structural epoxies can be very difficult to find for the optomechanical engineer. Usually, test data is only available for shear configuration at room temperature and fast pull rate. On the other hand, the slowly induced stress at extreme temperature is for many optical systems the worse-case scenario. Since one of the most referenced epoxy for optical assembly is the 3M™ Scotch-Weld™ Epoxy Adhesive EC-2216 B/A Gray, better understanding its behavior can benefit a broad range of applications. The objective of this paper is two-fold. First, review data for critical parameters such as Young's modulus and coefficient of thermal expansion. Secondly, derive failure criteria from correlation between a thermal stress experiment and a finite element model. Instead of pulling out a standard tensile specimen, it is proposed to test thin bondline geometry to replicate an optical device usage. Four test plates are assembled at the Institut National d'Optique (INO) in Quebec City, Canada with bondlines of 50 μm and 133 μm. To detect the failure of the epoxy, the low level vibration signature of a cantilever Invar plate is monitored as temperature changes. Following the finite element analysis, a failure criterion is found to better match the experimental results than generic lap shear data.

  13. My Experience with Ti-Ni-Based and Ti-Based Shape Memory Alloys

    Science.gov (United States)

    Miyazaki, Shuichi

    2017-12-01

    The present author has been studying shape memory alloys including Cu-Al-Ni, Ti-Ni-based, and Ni-free Ti-based alloys since 1979. This paper reviews the present author's research results for the latter two materials since 1981. The topics on the Ti-Ni-based alloys include the achievement of superelasticity in Ti-Ni alloys through understanding of the role of microstructures consisting of dislocations and precipitates, followed by the contribution to the development of application market of shape memory effect and superelasticity, characterization of the R-phase and monoclinic martensitic transformations, clarification of the basic characteristics of fatigue properties, development of sputter-deposited shape memory thin films and fabrication of prototypes of microactuators utilizing thin films, development of high temperature shape memory alloys, and so on. The topics of Ni-free Ti-based shape memory alloys include the characterization of the orthorhombic phase martensitic transformation and related shape memory effect and superelasticity, the effects of texture, omega phase and adding elements on the martensitic transformation and shape memory properties, clarification of the unique effects of oxygen addition to induce non-linear large elasticity, Invar effect and heating-induced martensitic transformation, and so on.

  14. Vibration-Assisted Femtosecond Laser Drilling with Controllable Taper Angles for AMOLED Fine Metal Mask Fabrication

    Science.gov (United States)

    Choi, Wonsuk; Kim, Hoon Young; Jeon, Jin Woo; Chang, Won Seok; Cho, Sung-Hak

    2017-01-01

    This study investigates the effect of focal plane variation using vibration in a femtosecond laser hole drilling process on Invar alloy fabrication quality for the production of fine metal masks (FMMs). FMMs are used in the red, green, blue (RGB) evaporation process in Active Matrix Organic Light-Emitting Diode (AMOLED) manufacturing. The taper angle of the hole is adjusted by attaching the objective lens to a micro-vibrator and continuously changing the focal plane position. Eight laser pulses were used to examine how the hole characteristics vary with the first focal plane’s position, where the first pulse is focused at an initial position and the focal planes of subsequent pulses move downward. The results showed that the hole taper angle can be controlled by varying the amplitude of the continuously operating vibrator during femtosecond laser hole machining. The taper angles were changed between 31.8° and 43.9° by adjusting the vibrator amplitude at a frequency of 100 Hz. Femtosecond laser hole drilling with controllable taper angles is expected to be used in the precision micro-machining of various smart devices. PMID:28772571

  15. Zero thermal expansion in YbGaGe due to an electronic valence transition.

    Science.gov (United States)

    Salvador, James R; Guo, Fu; Hogan, Tim; Kanatzidis, Mercouri G

    2003-10-16

    Most materials expand upon heating. Although rare, some materials expand on cooling, and are said to exhibit negative thermal expansion (NTE); but the property is exhibited in only one crystallographic direction. Such materials include silicon and germanium at very low temperature (Invar Fe-Ni alloys, ZrW2O3 (ref. 4) and certain molecular networks. NTE materials can be combined with materials demonstrating a positive thermal expansion coefficient to fabricate composites exhibiting an overall zero thermal expansion (ZTE). ZTE materials are useful because they do not undergo thermal shock on rapid heating or cooling. The need for such composites could be avoided if ZTE materials were available in a pure form. Here we show that an electrically conductive intermetallic compound, YbGaGe, can exhibit nearly ZTE--that is, negligible volume change between 100 and 400 K. We suggest that this response is due to a temperature-induced valence transition in the Yb atoms. ZTE materials are desirable to prevent or reduce resulting strain or internal stresses in systems subject to large temperature fluctuations, such as in space applications and thermomechanical actuators.

  16. Thermal expansion and transformation behavior of cerium and plutonium alloys: an application of the Aptekar-Ponyatovsky regular solution model

    Energy Technology Data Exchange (ETDEWEB)

    Lawson, A C; Lashley, J C, E-mail: aclawson@cybermesa.com [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2011-09-14

    In this paper we apply the Aptekar-Ponyatovsky (AP) regular solution thermodynamic model to the analysis of experimental data for the coefficient of thermal expansion (CTE) and determine the AP model parameters for unalloyed cerium metal, Ce-Th-La alloys, and Pu-Ga alloys. We find that the high temperature CTE of cerium metal follows the predictions of the AP model based on low temperature, high pressure data. For Ce-Th-La alloys we use the AP parameters to track the suppression of the first-order {gamma}-{alpha} cerium transition. We show the AP model accounts for the negative CTE observed for Pu-Ga alloys and is equivalent to an earlier invar model. Finally, we apply the AP parameters obtained for Pu-Ga alloys to rationalize the observed {delta}-{alpha} transformation pressures of these alloys. We show that the anomalous values of the Grueneisen and Grueneisen-Anderson parameters are important features of the thermal properties of plutonium. A strong analogy between the properties of plutonium and cerium is confirmed. (paper)

  17. Carbon Content of the Core through New Windows on the Earth's Interior

    Science.gov (United States)

    Li, J.; Gao, L.; Chen, B.; Zhao, J.; Alp, E. E.; Sturhahn, W.; Lavina, B.; Dera, P. K.

    2011-12-01

    The global carbon cycle may involve iron carbide as a component of the Earth's inner core. Placing constraints on the core's carbon content requires knowledge on the phase stability, density, and sound velocities of relevant iron-carbon alloys under the corresponding pressure and temperature conditions. Recent technological advances have opened new windows on viewing the structure and vibrational properties of iron-rich materials under megabar pressure and high temperature. Here we report new experimental results on the equations-of-state and phonon density-of-states of compressed Fe3C and Fe7C3 under core pressures and elevated temperatures. The measurements use specialized diamond-anvil cell designs and newly developed single-crystal X-ray diffraction (SXD) and nuclear resonant inelastic X-ray scattering (NRIXS) techniques. Our data reveal intriguing behavior of the two carbides under extreme conditions, including pressure-induced magnetic transitions, "invar-like" compressiblity, and significant phonon softening under high temperature. The results bear on the presence and role of carbon in the Earth's core.

  18. Development of magnetic moments in Fe1 - xNix-alloys

    Science.gov (United States)

    Glaubitz, Benjamin; Buschhorn, Stefan; Brüssing, Frank; Abrudan, Radu; Zabel, Hartmut

    2011-06-01

    We have investigated the magnetic properties of Fe1 - xNix-alloys for 13 different compositions ranging from pure Fe to pure Ni. The alloy series was prepared as thin films by co-deposition of Fe and Ni via ultra-high vacuum magnetron sputtering and the concentrations were determined by energy dispersive x-ray fluorescence analysis (EDX). The averaged magnetization and magnetic moment were measured at room temperature using a superconducting quantum interference device (SQUID) magnetometer and a vibrating sample magnetometer (VSM). Making use of x-ray magnetic circular dichroism (XMCD), the individual magnetic moments of Fe and Ni across the alloy concentration range were analyzed; thus their spin and orbital contributions were extracted. The weighted sum of the individual moments agrees very well with the average moments determined via SQUID and VSM. The Ni moment steadily increases from the pure Ni towards to the pure Fe range, while the Fe moment scatters around a value of about 2.4 µB. Close to the invar composition of x = 0.35 we do not observe an anomaly of the magnetic moments, either of the individual moments or of the average moment. We also discuss different assumptions for the analysis of the XMCD spectra and assess the results in the light of recent theoretical predictions and literature values.

  19. Magnetic and thermodynamic properties of face-centered cubic Fe-Ni alloys.

    Science.gov (United States)

    Lavrentiev, M Yu; Wróbel, J S; Nguyen-Manh, D; Dudarev, S L

    2014-08-14

    A model lattice ab initio parameterized Heisenberg-Landau magnetic cluster expansion Hamiltonian spanning a broad range of alloy compositions and a large variety of chemical and magnetic configurations has been developed for face-centered cubic Fe-Ni alloys. The thermodynamic and magnetic properties of the alloys are explored using configuration and magnetic Monte Carlo simulations over a temperature range extending well over 1000 K. The predicted face-centered cubic-body-centered cubic coexistence curve, the phase stability of ordered Fe3Ni, FeNi, and FeNi3 intermetallic compounds, and the predicted temperatures of magnetic transitions simulated as functions of alloy composition agree well with experimental observations. Simulations show that magnetic interactions stabilize the face-centered cubic phase of Fe-Ni alloys. Both the model Hamiltonian simulations and ab initio data exhibit a particularly large number of magnetic configurations in a relatively narrow range of alloy compositions corresponding to the occurrence of the Invar effect.

  20. Effects of Co doping on the metamagnetic states in fcc Fe1-xCox

    Science.gov (United States)

    de Coss, Romeo; Ortiz-Chi, Filiberto

    2012-02-01

    It is well known that fcc-Fe have shows metamagnetism, with a low-spin state (LS) at small volume and and a high-spin state (HS) at large volume in the total-energy vs volume curve. In this work, we have studied the evolution of the metamagnetic states in the Fe1-xCox alloy as a function of Co concentration by means of first principles calculations. The ground state properties were obtained using the Full-Potential Linear Augmented Plane Waves method and the Generalized Gradient Approximation for the exchange-correlation functional. The alloying was modeled using the self-consistent virtual crystal approximation. The magnetic states are obtained from the total-energy as a function of the spin moment calculations, obtained using the Fixed Spin Moment methodology. For fcc-Fe, we found that the ground state corresponds to the LS state. Increasing the Co concentration the HS state decrease in energy. Thus, for x=0.05 the energy of the LS and HS states is practically the same, corresponding to a spin-glass state. The LS state is substituted by a paramagnetic state for x>0.3 of Co concentration. Interestingly, for the alloy with x˜0.35 the total-energy vs volume curve shows ``effective symmetry,'' which is expected to exhibit invar behavior.

  1. Cu-Containing Fe-Ni Corrosion-Resistant Alloys Designed by a Cluster-Based Stable Solid Solution Model

    Science.gov (United States)

    Li, Baozeng; Wang, Qing; Wang, Yingmin; Li, Chunyan; Qiang, Jianbing; Ji, Chunjun; Dong, Chuang

    2012-02-01

    Copper is a good corrosion resisting element, but due to its immiscibility with Fe, it is only used as a minor-alloying element in stainless steels. In this work, we introduced a double-cluster structure model [CuNi12][NiFe12] m for stable solid solutions in Cu-containing Fe-Ni corrosion-resistant invar alloys. Our model takes into account all of the enthalpies between the element pairs by assuming Fe-Ni and Ni-Cu nearest neighbors and by avoiding Fe-Cu ones, so that the ideally stabilized structures are described by mixing two cuboctahedral clusters in the fcc lattice, NiFe12 and CuNi12. Two alloy series were designed by varying the relative proportions of the two clusters and the Cu contents. It was proved that the alloys with Cu contents below those prescribed by this model could easily be solutionized and water-quenched to a monolithic fcc solid solution, and resultant alloys possessed good corrosion-resisting properties in 3.5 wt pct NaCl solution.

  2. Electrodeposition of amorphous MnO x films on Fe-Ni substrates from aqueous sulfate solution

    Science.gov (United States)

    Pires, Manoel J. M.; Fernandes, Lucas S.

    2017-09-01

    Manganese oxides have a number of promising applications from new magnetic phases to high electrical capacitance systems. A common way of producing these materials is by electrochemical deposition using, for instance, baths with manganous acetate or chloride. As an alternative to acetate or chloride, we have used a solution with MnSO4 for the deposition of MnO x films on a magnetic alloy. Fe-Ni sheets with composition around the Invar point were used as substrates showing the practicability of this kind of growth of the Fe-Ni/MnO x system. The films were characterized by cyclic voltammetry, chronoamperometry, x-ray diffraction, optical and scanning electron microscopies. The obtained films are predominantly amorphous oxides with compositions tending to MnO2, and the most homogeneous samples were deposited from a solution with MnSO4 and H3BO3. Solutions with Na2SO4 and (NH4)2SO4 were also tested, but the resulting films were rather heterogeneous and presented poor adhesion to the Fe-Ni substrates. Direct deposition at constant electric potential as well as deposition by cycling the applied potential were analyzed, and the films prepared by both methods are very similar each other respect to morphology, composition and structure.

  3. Waveguides for Acoustic Power and Communication Channels

    Science.gov (United States)

    Litman, Robert B.

    A system for remote sensing of sealed or inaccessible environments has been developed which relies on acoustic waves for power transfer and communication. Acoustic waves are sent into a physical structure from the accessible side and harvested on the inaccessible side. The energy harvested is used to power a sensor and communications circuitry which sends the sensor reading back to the accessible side encoded in acoustic waves. Channels that extend axially along a length of pipe were simulated extensively using frequency-domain finite element analysis. Channels using a wedge shaped intermediary between the transducers and the pipe wall were the focus as prior research indicated that wedges improve channel efficiency. Numerous conclusions were drawn including that maximum channel efficiency increases as the intermediary wedges get shallower (incident angle increases towards 90 degrees) and excitation frequency increases. A second research aim was probing the feasibility and behavior of "acoustic fiber", the acoustic analogue to optical fiber. Again, frequency-domain FEA was employed. Heuristics governing the relationships between efficiency, physical dimensions, and frequency were produced. Finally, the problem of delamination of transducers from their steel substrates due to unequal thermal expansion was examined. Multiple epoxy adhesives were tested including one that maintained integrity at temperatures up to 150 degrees Celsius. Use of transition plates between the transducers and the steel substrates with intermediate coefficients of thermal expansion was also considered. Nickel-iron alloys kovar and invar proved to be effective at reducing the interfacial stresses that cause delamination while only slightly reducing acoustic performance.

  4. The ferromagnetic shape memory system Fe-Pd-Cu

    Energy Technology Data Exchange (ETDEWEB)

    Hamann, S. [Institute of Materials, Faculty of Mechanical Engineering, Ruhr-University Bochum, 44801 Bochum (Germany); Gruner, M.E. [Faculty of Physics and Center for Nanointegration, CeNIDE, University of Duisburg-Essen, 47048 Duisburg (Germany); Irsen, S. [Forschungszentrum caesar, Electron Microscopy, 53175 Bonn (Germany); Buschbeck, J. [IFW Dresden, P.O. Box: 270116, 01171 Dresden (Germany); Bechtold, C. [Inorganic Functional Materials, Christian-Albrechts-University, 24143 Kiel (Germany); Kock, I. [I. Physikalisches Institut, Georg-August-University Goettingen, 37077 Goettingen (Germany); Mayr, S.G. [I. Physikalisches Institut, Georg-August-University Goettingen, 37077 Goettingen (Germany)] [Leibniz-Institut fuer Oberflaechenmodifizierung eV, Translationszentrum fuer regenerative Medizin und Fakultaet fuer Physik und Geowissenschaften, University Leipzig, 04318 Leipzig (Germany); Savan, A.; Thienhaus, S. [Institute of Materials, Faculty of Mechanical Engineering, Ruhr-University Bochum, 44801 Bochum (Germany); Quandt, E. [Inorganic Functional Materials, Christian-Albrechts-University, 24143 Kiel (Germany); Faehler, S. [IFW Dresden, P.O. Box: 270116, 01171 Dresden (Germany); Entel, P. [Faculty of Physics and Center for Nanointegration, CeNIDE, University of Duisburg-Essen, 47048 Duisburg (Germany); Ludwig, A., E-mail: alfred.ludwig@rub.de [Institute of Materials, Faculty of Mechanical Engineering, Ruhr-University Bochum, 44801 Bochum (Germany)

    2010-10-15

    A new ferromagnetic shape memory thin film system, Fe-Pd-Cu, was developed using ab initio calculations, combinatorial fabrication and high-throughput experimentation methods. Reversible martensitic transformations are found in extended compositional regions, which have increased fcc-fct transformation temperatures in comparison to previously published results. High resolution transmission electron microscopy verified the existence of a homogeneous ternary phase without precipitates. Curie temperature, saturation polarization and orbital magnetism are only moderately decreased by alloying with nonmagnetic Cu. Compared to the binary system; enhanced Invar-type thermal expansion anomalies in terms of an increased volume magnetostriction are predicted. Complementary experiments on splat-fabricated bulk Fe-Pd-Cu samples showed an enhanced stability of the disordered transforming Fe{sub 70}Pd{sub 30} phase against decomposition. From the comparison of bulk and thin film results, it can be inferred that, for ternary systems, the Fe content, rather than the valence electron concentration, should be regarded as the decisive factor determining the fcc-fct transformation temperature.

  5. Effects of Co, Ni, and Cr addition on microstructure and magnetic properties of amorphous and nanocrystalline Fe86−xMxZr7Nb2Cu1B4 (M = Co, Ni, CoCr, and Cr, x = 0 or 6 alloys

    Directory of Open Access Journals (Sweden)

    Łukiewska Agnieszka

    2015-03-01

    Full Text Available Mössbauer spectra and thermomagnetic curves for the Fe86−xMxZr7Nb2Cu1B4 (M = Co, Ni, CoCr, and Cr, x = 0 or 6 alloys in the as-quenched state and after the accumulative annealing in the temperature range 600–800 K for 10 min are investigated. The parent Fe86Zr7Nb2Cu1B4 amorphous alloy is paramagnetic at room temperature, and substitution of 6 at.% of Fe by Co, Ni, and CoCr changes the magnetic structure – the alloys become ferromagnetic, whereas replacing 6 at.% of Fe with Cr preserves the paramagnetic state. After the heat treatment at 600 K, the decrease of the average hyperfine field induction, as compared to the as-quenched state, is observed due to the invar effect. After this annealing, the Curie temperature for all investigated alloys decreases. The accumulative annealing up to 800 K leads to the partial crystallization; α-Fe or α-FeCo grains with diameters in the range of 12–30 nm in the residual amorphous matrix appear.

  6. Magnetovolume effect in Ho{sub 2}Fe{sub 17-x}Mn{sub x} compounds

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J. L. [Institute for Superconductivity and Electronic Materials, University of Wollongong (Australia); Bragg Institute, ANSTO, Menai, NSW 2234 (Australia); School of Physical, Environmental and Mathematical Sciences, University of New South Wales, Canberra, ACT 2600 (Australia); Studer, A. J.; Kennedy, S. J. [Bragg Institute, ANSTO, Menai, NSW 2234 (Australia); Zeng, R.; Dou, S. X. [Institute for Superconductivity and Electronic Materials, University of Wollongong (Australia); Campbell, S. J. [School of Physical, Environmental and Mathematical Sciences, University of New South Wales, Canberra, ACT 2600 (Australia)

    2012-04-01

    The structural and magnetic properties of seven compounds in the Ho{sub 2}Fe{sub 17-x}Mn{sub x} series (x = 0-5) have been investigated. The spontaneous magnetization M{sub s} at 10 K exhibits a minimum at x{approx_equal} 3.8 while the 3d-sublattice magnetization M{sub T} is found to decrease at {approx} -3.4 {mu}{sub B}/per Mn atom compared with the rate of {approx}-2.0 {mu}{sub B}/per Mn atom expected from a simple dilution model. All of the Ho{sub 2}Fe{sub 17-x}Mn{sub x} compounds exhibit anisotropic thermal expansion below their Curie temperatures leading to the presence of strong magnetovolume effects and Invar-type behavior below T{sub C}. An approximately zero volume thermal expansion has been detected between 10 K and 270 K for Ho{sub 2}Fe{sub 17}. The maximum magnetic entropy changes for Ho{sub 2}Fe{sub 17-x}Mn{sub x} with x = 0 and 2.0 are 3.2 J kg{sup -1} K{sup -1} around T{sub C} {approx} 336 K and 2.7 J kg{sup -1} K{sup -1} around T{sub C} {approx} 302 K, respectively, for magnetic field change of B = 0-5 T.

  7. Thermal-expansion anisotropy of orthorhombic martensite in the two-phase (α + β) titanium alloy

    Science.gov (United States)

    Demakov, S. L.; Stepanov, S. I.; Illarionov, A. G.; Ryzhkov, M. A.

    2017-03-01

    Anisotropy of the thermal expansion coefficient (TEC) has been revealed along the axes of the crystal lattice of the α″ titanium martensite in the two-phase (α + β) titanium alloy of grade VT16 (Ti-3Al-5V-4.5Mo, wt %). It has been established by the method of in situ X-ray diffraction analysis that the lattice parameter b of the orthorhombic martensite obtained by quenching from different temperatures decreases upon heating. The TECs along the axes of the crystal lattice of the martensite obtained by quenching from different temperatures have been calculated. It has been shown that the uniaxial extension of bars of the VT16 alloy quenched for the metastable β phase with relative deformations of 0.7, 1, 2, 3, 4, 5, 6, and 8% leads to the formation of the deformation-induced martensite with an axial texture along the b direction of the martensite lattice. In the course of dilatometric studies of the deformed bars, it has been established that there are two temperature intervals (from-100 to +70°C and from 150 to 300°C) with a low TEC. In the first interval, the value of the TEC varies from-2 × 10-6 to +8 × 10-6 K-1 and is determined by the volume fraction of the oriented α″ martensite. This Invar effect is one-dimensional and is manifested along the b axis of the martensite.

  8. Atomistic Modeling of the Negative Thermal Expansion in δ- Plutonium  Based on the Two-State Description

    Directory of Open Access Journals (Sweden)

    Steven M. Valone

    2012-06-01

    Full Text Available The δ phase  of plutonium with the fcc structure exhibits an unusual negative thermal expansion (NTE over its narrow  temperature range of stability, 593–736 K. An accurate description  of the anomalous high-temperature volume effect of plutonium  goes beyond the current capability  of electronic-structure  calculations.  We propose an atomistic scheme to model the thermodynamic properties of δ-Pu based on the two-state model of Weiss for the Invar alloys, inspired by the simple free-energy analysis previously conducted by Lawson et al. The two-state mechanism is incorporated into the atomistic description of a many-body  interacting  system.  Two modified  embedded atom method potentials are employed to represent the binding energies of two competing  electronic  states in δ-Pu. We demonstrate how the NTE takes place in δ-Pu by means of Monte Carlo simulations implemented with the two-state mechanism.

  9. Influence of Co substitution on magnetoelastic properties of Er{sub 2}Fe{sub 14-x}Co{sub x}B (x = 1, 3 and 5) intermetallic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Khoshnoud, D. Sanavi [Faculty of Science, Department of Physics, Ferdowsi University of Mashhad, Mashhad, Khorasan Razavi (Iran, Islamic Republic of); Tajabor, N. [Faculty of Science, Department of Physics, Ferdowsi University of Mashhad, Mashhad, Khorasan Razavi (Iran, Islamic Republic of)], E-mail: tajabor@ferdowsi.um.ac.ir; Fruchart, D.; Gignoux, D.; Miraglia, S. [Institut. Neel, Departement MCMF, Groupe IICF, BP 166, 38042 Grenoble Cedex 9 (France); Pourarian, F. [Department of Material Science and Engineering, Carengie Mellon University, Pittsburgh, PA 15219 (United States)

    2009-07-08

    The magnetostriction and thermal expansion of Er{sub 2}Fe{sub 14-x}Co{sub x}B (x = 1, 3 and 5) intermetallic compounds were measured, using the strain gauge method in the temperature range 75-450 K under applied magnetic fields up to 1.5 T. For all samples the longitudinal magnetostriction ({lambda}{sub l}) undergoes an anomaly around the spin reorientation temperature (T{sub SR}). It is also observed that {lambda}{sub l} decreases with increasing the Co content. All compounds show saturation type behaviour in their anisotropic magnetostriction curves at different temperatures and applied fields. The saturation behaviour of the compound with x = 3 occurs at higher temperatures than with x = 1 and 5. The volume magnetostriction strongly increases below {mu}{sub 0}H = 0.3 T, then monotonically rises with applied field up to the spin reorientation temperature. An invar type behaviour is observed above 200 K in the compound with x = 1. The results are discussed based on the temperature dependence of magnetocrystalline anisotropy of compounds below and above their T{sub SR}.

  10. Contrast enhancement of ultrasonic imaging of internal stresses in materials.

    Science.gov (United States)

    Landa, Michal; Plesek, Jirí

    2002-05-01

    The ultrasonic methods, which detect applied or residual stress in materials, are based on nonlinear interaction of a small dynamic disturbance (acoustic waves) with the pre-deformed state of the solid. This weak phenomenon (acoustoelasticity) leads to a dependence of acoustic wave velocities on the initial stress, and a stress-induced anisotropy in the acoustical properties of the material. In anisotropic media, the transversal wave velocity depends on its polarization. The amplitude of the conical polarized shear wave, propagating through a plate specimen, is sensitive to pre-stress due to acoustoelastic birefringence. The resulting scan image is created by variations of the amplitude. The previous description is a basic principle of the approach used for stress mapping in Al-alloys by time-resolved acoustic microscopy. Disk specimens with central stress concentrators are loaded step by step. The acoustic scans are created during each loading step. Thermal stress detection is also shown on specimens with an Invar core. The original image processing procedure has been developed to improve edge detection of obtained stress maps. The acoustic images are compared with theoretically predicted isocline contours. The inherent material anisotropy and the structural inhomogeneities influence significantly the acoustoelastic measurements. Advantages and limitations of the nondestructive technique are summarized on the basis of presented experimental results.

  11. Thermal expansion and transformation behavior of cerium and plutonium alloys: an application of the Aptekar-Ponyatovsky regular solution model

    Science.gov (United States)

    Lawson, A. C.; Lashley, J. C.

    2011-09-01

    In this paper we apply the Aptekar-Ponyatovsky (AP) regular solution thermodynamic model to the analysis of experimental data for the coefficient of thermal expansion (CTE) and determine the AP model parameters for unalloyed cerium metal, Ce-Th-La alloys, and Pu-Ga alloys. We find that the high temperature CTE of cerium metal follows the predictions of the AP model based on low temperature, high pressure data. For Ce-Th-La alloys we use the AP parameters to track the suppression of the first-order γ-α cerium transition. We show the AP model accounts for the negative CTE observed for Pu-Ga alloys and is equivalent to an earlier invar model. Finally, we apply the AP parameters obtained for Pu-Ga alloys to rationalize the observed δ-α transformation pressures of these alloys. We show that the anomalous values of the Grüneisen and Grüneisen-Anderson parameters are important features of the thermal properties of plutonium. A strong analogy between the properties of plutonium and cerium is confirmed.

  12. Development of magnetic moments in Fe{sub 1-x}Ni{sub x}-alloys

    Energy Technology Data Exchange (ETDEWEB)

    Glaubitz, Benjamin; Buschhorn, Stefan; Bruessing, Frank; Abrudan, Radu; Zabel, Hartmut [Institut fuer Experimentalphysik/Festkoerperphysik, Ruhr-Universitaet Bochum, 44780 Bochum (Germany)

    2011-06-29

    We have investigated the magnetic properties of Fe{sub 1-x}Ni{sub x}-alloys for 13 different compositions ranging from pure Fe to pure Ni. The alloy series was prepared as thin films by co-deposition of Fe and Ni via ultra-high vacuum magnetron sputtering and the concentrations were determined by energy dispersive x-ray fluorescence analysis (EDX). The averaged magnetization and magnetic moment were measured at room temperature using a superconducting quantum interference device (SQUID) magnetometer and a vibrating sample magnetometer (VSM). Making use of x-ray magnetic circular dichroism (XMCD), the individual magnetic moments of Fe and Ni across the alloy concentration range were analyzed; thus their spin and orbital contributions were extracted. The weighted sum of the individual moments agrees very well with the average moments determined via SQUID and VSM. The Ni moment steadily increases from the pure Ni towards to the pure Fe range, while the Fe moment scatters around a value of about 2.4 {mu}{sub B}. Close to the invar composition of x = 0.35 we do not observe an anomaly of the magnetic moments, either of the individual moments or of the average moment. We also discuss different assumptions for the analysis of the XMCD spectra and assess the results in the light of recent theoretical predictions and literature values.

  13. Elastic softening in Fe7C3 with implications for Earth's deep carbon reservoirs

    Science.gov (United States)

    Liu, Jiachao; Li, Jie; Ikuta, Daijo

    2016-03-01

    Iron carbide Fe7C3 has recently emerged as a potential host of reduced carbon in Earth's mantle and a candidate component of the inner core, but the equation of state of Fe7C3 is still uncertain, partly because the nature of pressure-induced magnetic transitions in Fe7C3 and their elastic effects remain controversial. Here we report the compression curve of hexagonal Fe7C3 in neon medium with dense pressure sampling and in comparison with pure iron in the same loading. The results revealed elastic softening between 7 GPa and 20 GPa, which can be attributed to noncollinear alignment of spin moments in a state between the ferromagnetic and paramagnetic phases, as expected for Invar-type alloys. The volume reduction associated with the softening would enhance the stability of Fe7C3 in the deeper part of the upper mantle and transition zone. As a result of subsequent spin crossover at higher pressures, Fe7C3 at inner core conditions likely occurs as the nonmagnetic phase, which remains a candidate for the major component of the Earth's central sphere.

  14. Phase Equilibria of the Fe-Ni-Sn Ternary System at 270°C

    Science.gov (United States)

    Huang, Tzu-Ting; Lin, Shih-Wei; Chen, Chih-Ming; Chen, Pei Yu; Yen, Yee-Wen

    2016-12-01

    The Fe-42 wt.% Ni alloy, also known as a 42 invar alloy (Alloy 42), is used as a lead-frame material because its thermal expansion coefficient is much closer to Si substrate than Cu or Ni substrates. In order to enhance the wettability between the substrate and solder, the Sn layer was commonly electroplated onto the Alloy 42 surface. A clear understanding of the phase equilibria of the Fe-Ni-Sn ternary system is necessary to ensure solder-joint reliability between Sn and Fe-Ni alloys. To determine the isothermal section of the Fe-Ni-Sn ternary system at 270°C, 26 Fe-Ni-Sn alloys with different compositions were prepared. The experimental results confirmed the presence of the Fe3Ni and FeNi phases at 270°C. Meanwhile, it observed that the isothermal section of the Fe-Ni-Sn ternary system was composed of 11 single-phase regions, 19 two-phase regions and nine tie-triangles. Moreover, no ternary compounds were found in the Fe-Ni-Sn system at 270°C.

  15. Moessbauer spectroscopy study of the crystallisation behaviour of Fe-Ni-Si-P amorphous powders prepared by ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Sunol, J.J. [Girona Univ. (Spain). Grup de Recerca en Materials; Pradell, T. [Univ. Politecnica de Catalunya, Barcelona (Spain). ESAB; Clavaguera, N. [Fisica de l' Estat Solid, Univ. de Barcelona (Spain); Clavaguera-Mora, M.T. [Universitat Autonoma de Barcelona (Spain). Dept. de Fisica

    2001-07-01

    Crystallisation of ball milled amorphous powders with the overall composition Fe{sub 40}Ni{sub 40}P{sub 20-x}Si{sub x} (x=6, 10, 14) are studied by X-ray diffraction and transmission Moessbauer spectroscopy. Structural relaxation and growth of preexisting phases appear at temperatures below 473 K. Further annealing at higher temperature results in the complete crystallization of the material. Different amorphisation ability of the resulting amorphous powders is determined as a function of the Si/P content. The crystallisation products determined - Fe(Si) bcc and Fe-Ni fcc phases, Ni rich silicides and Fe-Ni phosphides- are the same as those obtained after crystallization of melt spun amorphous alloys of the same composition. The collapse of the magnetic hyperfine field, characteristic of INVAR Fe-Ni fcc phases with compositions in the 30-40 at% Ni range, is observed. However, this magnetic collapse is not obtained in the corresponding amorphous alloys obtained by melt spinning which, on the contrary, show the precipitation of both ferromagnetic and paramagnetic Fe-Ni fcc phases. Although this behaviour seems to indicate the precipitation of Fe-richer phases, the mechanical stresses introduced in the material are also known to be able to induce such different magnetic behaviour. (orig.)

  16. Injection moulding of low expansion Fe-Ni-Co alloys

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, R.M. do; Justino, J.G.; Fredel, M.C.; Wendhausen, P.A.P.; Klein, A.N.; Almeida Buschinelli, A.J. de [Dept. of Mechanical Engineering, Univ. Federal de Santa Catarina Florianopolis (Brazil)

    2001-07-01

    Low-expansion alloys (Fe-Ni-Co) are used in specific applications that require accurate dimensional control, such as standards for length measurement, radar resonant cavities, components for nuclear reactors and parts for ceramic-metal joining. This work investigates the production of the Fe-28%Ni-18%Co and Fe-28%Ni-23%Co alloys by powder injection moulding. The mixtures were characterised in the capillar rheometer. The microstructure was characterised with a scanning electron microscope and X-ray diffraction and the coefficient of thermal expansion determined with a linear dilatometer. The mixtures presented a pseudoplastic rheological behaviour and a viscosity level adequate to the injection moulding. The microstructure of the two alloys was constituted of an austenitic phase and the residual porosity (8.5%). Dilatometric behaviour of two alloys is characterised by two distinct regions, demonstrating the presence of the Invar effect and different transition temperature depending on the cobalt content. Coefficients of thermal expansion for both alloys can be considered adequate for brazing with alumina. (orig.)

  17. FUNDAMENTAL STUDIES OF THE DURABILITY OF MATERIALS FOR INTERCONNECTS IN SOLID OXIDE FUEL CELLS

    Energy Technology Data Exchange (ETDEWEB)

    Frederick S. Pettit; Gerald H. Meier

    2003-06-30

    This report describes the result of the first eight months of effort on a project directed at improving metallic interconnect materials for solid oxide fuel cells (SOFCs). The results include cyclic oxidation studies of a group of ferritic alloys, which are candidate interconnect materials. The exposures have been carried out in simulated fuel cell atmospheres. The oxidation morphologies have been characterized and the ASR has been measured for the oxide scales. The effect of fuel cell electric current density on chromia growth rates has been considered The thermomechanical behavior of the scales has been investigated by stress measurements using x-ray diffraction and interfacial fracture toughness measurements using indentation. The ultimate goal of this thrust is to use knowledge of changes in oxide thickness, stress and adhesion to develop accelerated testing methods for evaluating SOFC interconnect alloys. Finally a theoretical assessment of the potential for use of ''new'' metallic materials as interconnect materials has been conducted and is presented in this report. Alloys being considered include materials based on pure nickel, materials based on the ''Invar'' concept, and coated materials to optimize properties in both the anode and cathode gases.

  18. Polarized x-ray absorption spectroscopy for the study of superconductors and magnetic materials

    Science.gov (United States)

    Ramanathan, Mohan; Alp, Esen E.; Mini, Susan M.; Salem-Sugui, S.; Bommannavar, A.

    1991-11-01

    Synchrotron radiation is a good source of polarized radiation in the x-ray regime. The radiation obtained from a bending magnet source is linearly polarized in the bending plane and has a varying degree of circular polarization away from the bending plane. This feature of synchrotron radiation can be taken advantage of with proper optics to selectively use the type of polarized radiation required for the experiment in question. Linear polarized radiation is used to study the anisotropic nature of electronic and atomic structure by x-ray absorption techniques from single crystal and oriented powder samples. We will give a specific example of the use of linearly polarized x-ray absorption spectroscopy measurements for the study of the magnetically oriented layered copper oxide superconductors. While such linear dichroism measurements help identify the symmetry of the empty electronic states, circular dichroism measurements in magnetic systems help in determining the spin contribution to the absorption process. We will discuss magnetic circular dichroism measurements of the ordered-disordered invar alloy Fe(subscript 3)Pt.

  19. Nuclear power plant prestressed concrete containment vessel structure monitoring during integrated leakage rate test using three kinds of fiber optic sensors

    Science.gov (United States)

    Liao, Kaixing; Li, Jinke; Kong, Xianglong; Sun, Changsen; Zhao, Xuefeng

    2017-04-01

    After years of operation, the safety of the prestressed concrete containment vessel (PCCV) structure of Nuclear Power Plant (NPP) is an important aspect. In order to detect the strength degradation and the structure deformation, several sensors such as vibrating wire strain gauge, invar wires and pendulums were installed in PCCV. However, the amounts of sensors above are limited due to the cost. Due to the well durability of fiber optic sensors, three kinds of fiber optic sensors were chosen to install on the surface of PCCV to monitor the deformation during Integrated Leakage Rate Test (ILRT). The three kinds of fiber optic sensors which had their own advantages and disadvantages are Fiber Bragg Grating (FBG), white light interferometry (WLI) and Brillouin Optical Time Domain Analysis (BOTDA). According to the measuring data, the three fiber optic sensors worked well during the ILRT. After the ILRT, the monitoring strain was recoverable thus the PCCV was still in the elastic stage. If these three kinds of fiber optic sensors are widely used in the PCCV, the unusual deformations are easier to detect. As a consequence, the three fiber optic sensors have good potential in the structure health monitoring of PCCV.

  20. Design and functional tests of the Euclid grism mount

    Science.gov (United States)

    Rossin, Ch.; Grange, R.; Caillat, A.; Costille, A.; Sanchez, P.; Ceria, W.

    2017-11-01

    The Euclid mission selected by ESA in the Cosmic Vision program is dedicated to understand dark energy and dark matter. One of the probes based on detection of Baryonic Acoustic Oscillations required the redshift of millions of galaxies. This massive spectroscopic survey relies on the Near Infrared SpectroPhotometer (NISP) using grism in slitless mode. In this Euclid NISP context, we designed a cryogenic mount for the four grisms of the spectroscopic channel. This mount has to maintain optical performances and alignment at the cryogenic temperature of 120K and to survive launch vibrations. Due to a very small mass and volume budget allowed in the Grism Wheel Assembly our design relies on a weight relief Invar ring glued to the grism by tangential flexures. Tangential flexures have the advantage of small height but the drawback of less decoupling capabilities than bipods. We will present the design of the mount and the integration and functional tests to stay within the 60 nm RMS transmitted wavefront error budget allowed to the grism.

  1. Temperature Effects on Adhesive Bond Strengths and Modulus for Commonly Used Spacecraft Structural Adhesives

    Science.gov (United States)

    Ojeda, Cassandra E.; Oakes, Eric J.; Hill, Jennifer R.; Aldi, Dominic; Forsberg, Gustaf A.

    2011-01-01

    A study was performed to observe how changes in temperature and substrate material affected the strength and modulus of an adhesive bondline. Seven different adhesives commonly used in aerospace bonded structures were tested. Aluminum, titanium and Invar adherends were cleaned and primed, then bonded using the manufacturer's recommendations. Following surface preparation, the coupons were bonded with the adhesives. The single lap shear coupons were then pull tested per ASTM D 1002 Standard Test Method for Apparent Shear Strength of Single- Lap-Joint over a temperature range from -150 deg C up to +150 deg C. The ultimate strength was calculated and the resulting data were converted into B-basis design allowables. Average and Bbasis results were compared. Results obtained using aluminum adherends are reported. The effects of using different adherend materials and temperature were also studied and will be reported in a subsequent paper. Dynamic Mechanical Analysis (DMA) was used to study variations in adhesive modulus with temperature. This work resulted in a highly useful database for comparing adhesive performance over a wide range of temperatures, and has facilitated selection of the appropriate adhesive for spacecraft structure applications.

  2. The Lyman Alpha Imaging-Monitor Experiment (LAIME) for TESIS/CORONAS-PHOTON

    Science.gov (United States)

    Damé, L.; Koutchmy, S.; Kuzin, S.; Lamy, P.; Malherbe, J.-M.; Noëns, J.-C.

    LAIME the Lyman Alpha Imaging-Monitor Experiment is a remarkably simple no mechanisms and compact 100x100x400 mm full Sun imager to be flown with TESIS on the CORONAS-PHOTON mission launch expected before mid-2008 As such it will be the only true chromospheric imager to be flown in the next years supporting TESIS EUV-XUV imaging SDO and the Belgian LYRA Lyman Alpha flux monitor on the ESA PROBA-2 microsatellite launch expected in September 2007 We will give a short description of this unique O60 mm aperture imaging telescope dedicated to the investigating of the magnetic sources of solar variability in the UV and chromospheric and coronal disruptive events rapid waves Moreton waves disparitions brusques of prominences filaments eruptions and CMEs onset The resolution pixel is 2 7 arcsec the field of view 1 4 solar radius and the acquisition cadence could be as high as 1 image minute The back thinned E2V CCD in the focal plane is using frame transfer to avoid shutter and mechanisms Further more the double Lyman Alpha filtering allows a 40 AA FWHM bandwidth and excellent rejection yet providing a vacuum seal design of the telescope MgF2 entrance window Structural stability of the telescope focal length 1 m is preserved by a 4-INVAR bars design with Aluminium compensation in a large pm 10 o around 20 o

  3. Measurement of W + bb and a search for MSSM Higgs bosons with the CMS detector at the LHC

    Science.gov (United States)

    O'Connor, Alexander Pinpin

    Tooling used to cure composite laminates in the aerospace and automotive industries must provide a dimensionally stable geometry throughout the thermal cycle applied during the part curing process. This requires that the Coefficient of Thermal Expansion (CTE) of the tooling materials match that of the composite being cured. The traditional tooling material for production applications is a nickel alloy. Poor machinability and high material costs increase the expense of metallic tooling made from nickel alloys such as 'Invar 36' or 'Invar 42'. Currently, metallic tooling is unable to meet the needs of applications requiring rapid affordable tooling solutions. In applications where the tooling is not required to have the durability provided by metals, such as for small area repair, an opportunity exists for non-metallic tooling materials like graphite, carbon foams, composites, or ceramics and machinable glasses. Nevertheless, efficient machining of brittle, non-metallic materials is challenging due to low ductility, porosity, and high hardness. The machining of a layup tool comprises a large portion of the final cost. Achieving maximum process economy requires optimization of the machining process in the given tooling material. Therefore, machinability of the tooling material is a critical aspect of the overall cost of the tool. In this work, three commercially available, brittle/porous, non-metallic candidate tooling materials were selected, namely: (AAC) Autoclaved Aerated Concrete, CB1100 ceramic block and Cfoam carbon foam. Machining tests were conducted in order to evaluate the machinability of these materials using end milling. Chip formation, cutting forces, cutting tool wear, machining induced damage, surface quality and surface integrity were investigated using High Speed Steel (HSS), carbide, diamond abrasive and Polycrystalline Diamond (PCD) cutting tools. Cutting forces were found to be random in magnitude, which was a result of material porosity. The

  4. An assessment of the homogeneity of nano-crystalline Fe–Cu powders as studied by means of APT

    KAUST Repository

    Wille, Catharina

    2009-04-01

    In this contribution the homogeneity of mechanically alloyed Fe-Cu powders for two different compositions (Fe-10 and Fe-2.5 at%Cu) has been systematically characterised by atom probe tomography. Since Fe-Cu exhibits the Invar effect, it is among the most attractive systems for technical application. Furthermore, this system is immiscible and characterised by a large positive heat of mixing. In combination with the widespread application and accessibility, this predestines Fe-Cu as a binary model alloy to elaborate the enforced nonequilibrium enhanced solubility for immiscible systems. Depending on the parameters composition and milling time, results on the extension of the solubility limit and on the homogeneity of the alloy are presented, discussed and compared to earlier works. Only for the alloy with lower Cu content and for the prolonged milling time of 50 h, chemical homogeneity of the sample as measured by the atom probe was fully reached on the nano-scale. For all other parameter combinations homogeneity could not be achieved, even for long milling times and for those samples that appear to be homogeneous via X-ray analysis. Moreover, impurities were determined, mostly stemming from the fabrication procedure. The arrangement and homogeneity of the most common impurity, oxygen, was evaluated from atom probe data for different samples. Thus, the local concentration, segregation effects and the distribution of impurities could be quantified on the nano-scale, depending on the different nominal compositions and processing parameters. Additionally, structural information could be gained employing transmission electron microscopy and diffraction measurements. (C) 2008 Elsevier B.V. All rights reserved.

  5. Degradation Characterization of Thermal Interface Greases: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    DeVoto, Douglas J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Major, Joshua [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Paret, Paul P [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Blackman, G. S. [DuPont Experimental Station; Wong, A. [DuPont Experimental Station; Meth, J. S. [DuPont Experimental Station

    2017-08-03

    Thermal interface materials (TIMs) are used in power electronics packaging to minimize thermal resistance between the heat generating component and the heat sink. Thermal greases are one such class. The conformability and thin bond line thickness (BLT) of these TIMs can potentially provide low thermal resistance throughout the operation lifetime of a component. However, their performance degrades over time due to pump-out and dry-out during thermal and power cycling. The reliability performance of greases through operational cycling needs to be quantified to develop new materials with superior properties. NREL, in collaboration with DuPont, has performed thermal and reliability characterization of several commercially available thermal greases. Initial bulk and contact thermal resistance of grease samples were measured, and then the thermal degradation that occurred due to pump-out and dry-out during temperature cycling was monitored. The thermal resistances of five different grease materials were evaluated using NREL's steady-state thermal resistance tester based on the ASTM test method D5470. Greases were then applied, utilizing a 2.5 cm x 2.5 cm stencil, between invar and aluminum plates to compare the thermomechanical performance of the materials in a representative test fixture. Scanning Acoustic microscopy, thermal, and compositional analyses were performed periodically during thermal cycling from -40 degrees Celcius to 125 degrees Celcius. Completion of this characterization has allowed for a comprehensive evaluation of thermal greases both for their initial bulk and contact thermal performance, as well as their degradation mechanisms under accelerated thermal cycling conditions.

  6. Thermal evolution of exchange interactions in lightly doped barium hexaferrites

    Energy Technology Data Exchange (ETDEWEB)

    Trukhanov, S.V., E-mail: truhanov@ifttp.bas-net.by [National University of Science and Technology MISiS, Leninsky Prospekt, 4, 119049 Moscow (Russian Federation); SSPA “Scientific and practical materials research centre of NAS of Belarus”, P. Brovki Str., 19, 220072 Minsk, Belorussia (Belarus); Trukhanov, A.V. [National University of Science and Technology MISiS, Leninsky Prospekt, 4, 119049 Moscow (Russian Federation); SSPA “Scientific and practical materials research centre of NAS of Belarus”, P. Brovki Str., 19, 220072 Minsk, Belorussia (Belarus); Kostishyn, V.G.; Panina, L.V. [National University of Science and Technology MISiS, Leninsky Prospekt, 4, 119049 Moscow (Russian Federation); Turchenko, V.A. [Joint Institute for Nuclear Research, Joliot-Curie Str., 141980 Dubna (Russian Federation); Donetsk Institute of Physics and Technology named after A.A. Galkin of the NAS of Ukraine, 72 R.Luxemburg Str., 83114 Donetsk (Ukraine); Kazakevich, I.S. [SSPA “Scientific and practical materials research centre of NAS of Belarus”, P. Brovki Str., 19, 220072 Minsk, Belorussia (Belarus); Trukhanov, An.V. [National University of Science and Technology MISiS, Leninsky Prospekt, 4, 119049 Moscow (Russian Federation); SSPA “Scientific and practical materials research centre of NAS of Belarus”, P. Brovki Str., 19, 220072 Minsk, Belorussia (Belarus); Trukhanova, E.L.; Natarov, V.O. [SSPA “Scientific and practical materials research centre of NAS of Belarus”, P. Brovki Str., 19, 220072 Minsk, Belorussia (Belarus); Balagurov, A.M. [Joint Institute for Nuclear Research, Joliot-Curie Str., 141980 Dubna (Russian Federation)

    2017-03-15

    The lightly doped BaFe{sub 12−x}D{sub x}O{sub 19} (D=Al{sup 3+}, In{sup 3+}; x=0.1 and 0.3) polycrystalline hexaferrite samples have been investigated by powder neutron diffractometry as well as by vibration sample magnetometry in a wide temperature range from 4 K up to 740 K and in magnetic field up to 14 T to establish the nature of Fe{sup 3+}(Al{sup 3+}, In{sup 3+}) – O{sup 2-} - Fe{sup 3+}(Al{sup 3+}, In{sup 3+}) indirect exchange interactions. The crystal structure features such as the ionic coordinates and lattice parameters have been defined and Rietveld refined. The Invar effect has been observed in low temperature range below 150 K. It was explained by the thermal oscillation anharmonicity of ions. It is established that the ferrimagnet-paramagnet phase transition is a standard second-order one. From the macroscopic magnetization measurement the Curie temperature and ordered magnetic moment per nominal iron ion are obtained. From the microscopic diffraction measurement the magnetic moments at all the nonequivalent ionic positions and total magnetic moment per iron ion have been obtained at different temperatures down to 4 K. The light diamagnetic doping mechanism and magnetic structure model are proposed. The effect of light diamagnetic doping on nature of Fe{sup 3+}(Al{sup 3+}, In{sup 3+}) – O{sup 2-} - Fe{sup 3+}(Al{sup 3+}, In{sup 3+}) indirect exchange interactions with temperature increase is discussed. - Highlights: • Crystal structure for lightly doped barium hexaferrites was investigated. • Atomic coordinates and lattice parameters were Rietveld refined. • Magnetic properties for lightly doped barium hexaferrites was investigated. • Magnetic structure for lightly doped barium hexaferrites was investigated. • Magnetic moments at different position and total moment per iron ion were defined.

  7. Degradation Characterization of Thermal Interface Greases

    Energy Technology Data Exchange (ETDEWEB)

    Major, Joshua [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Narumanchi, Sreekant V [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Paret, Paul P [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Blackman, Gregory [DuPont; Wong, Arnold [DuPont; Meth, Jeffery [DuPont

    2018-02-12

    Thermal interface materials (TIMs) are used in power electronics packaging to minimize thermal resistance between the heat generating component and the heat sink. Thermal greases are one such class. The conformability and thin bond line thickness (BLT) of these TIMs can potentially provide low thermal resistance throughout the operation lifetime of a component. However, their performance degrades over time due to pump-out and dry-out during thermal and power cycling. The reliability performance of greases through operational cycling needs to be quantified to develop new materials with superior properties. NREL, in collaboration with DuPont, has performed thermal and reliability characterization of several commercially available thermal greases. Initial bulk and contact thermal resistance of grease samples were measured, and then the thermal degradation that occurred due to pump-out and dry-out during temperature cycling was monitored. The thermal resistances of five different grease materials were evaluated using NREL's steady-state thermal resistance tester based on the ASTM test method D5470. Greases were then applied, utilizing a 2.5 cm x 2.5 cm stencil, between invar and aluminum plates to compare the thermomechanical performance of the materials in a representative test fixture. Scanning Acoustic microscopy, thermal, and compositional analyses were performed periodically during thermal cycling from -40 degrees C to 125 degrees C. Completion of this characterization has allowed for a comprehensive evaluation of thermal greases both for their initial bulk and contact thermal performance, as well as their degradation mechanisms under accelerated thermal cycling conditions.

  8. Local thermal expansions and lattice strains in Elinvar and stainless steel alloys

    Science.gov (United States)

    Yokoyama, Toshihiko; Koide, Akihiro; Uemura, Yohei

    2018-02-01

    Local thermal expansions and lattice strains in the Elinvar alloy Fe49.66Ni42.38Cr5.49Ti2.47 (Ni Span C) and the stainless steel SUS304 Fe71.98Ni9.07Cr18.09Mn0.86 (AISI304) were investigated by the temperature-dependent Cr, Fe, and Ni K -edge extended x-ray absorption fine-structure (EXAFS) measurements, combined with the path-integral effective classical potential Monte Carlo (PIECP MC) theoretical simulations. From the EXAFS analysis of the Elinvar alloy, the local thermal expansion around Fe is found to be considerably smaller than the ones around Ni and Cr. This observation can be understood simply because Fe in the Elinvar alloy exhibit an incomplete Invar-like effect. Moreover, in both the Elinvar and SUS304 alloys, the local thermal expansions and the lattice strains around Cr are found to be larger than those around Fe and Ni. From the PIECP MC simulations of both the alloys, the first-nearest neighbor Cr-Fe pair shows extraordinarily large thermal expansion, while the Cr-Cr pair exhibits quite small or even negative thermal expansion. These findings consequently indicate that the lattice strains in both the Elinvar and SUS304 alloys are concentrated predominantly on the Cr atoms. Although the role of Cr in stainless steel has been known to inhibit corrosion by the formation of surface chromium oxide, the present investigation may interestingly suggest that the Cr atoms in the bulk play a hidden new role of absorbing inevitable lattice strains in the alloys.

  9. Magnetic entropy changes at early stages of nanocrystallization in amorphous Fe{sub 90}Zr{sub 7}B{sub 3} ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Swierczek, J., E-mail: swiercz@wip.pcz.pl [Institute of Physics, Czestochowa University of Technology, al. Armii Krajowej 19, 42-200 Czestochowa (Poland); Mydlarz, T. [International Laboratory of High Magnetic Fields and Low Temperatures, ul.Gajowicka 95, 53-421 Wroclaw (Poland)

    2011-09-22

    Highlights: > Magnetic entropy changes in partially crystallized Fe{sub 90}Zr{sub 7}B{sub 3} alloy. > Microstructure by transmission electron microscopy and Moessbauer spectrometry. > Superparamagnetic {alpha}-Fe particles in amorphous matrix. > Curie temperature of matrix increases on annealing. > Maximum entropy changes remain almost unchanged. - Abstract: Microstructure, revealed by transmission electron microscopy and conventional Moessbauer spectroscopy, magnetization versus magnetizing field induction and temperature and isothermal magnetic entropy changes in the as-quenched and subjected to annealing at T{sub a1} = 723 K for 2 or 3 h and at T{sub a2} = 743 K for 2.5 h of Fe{sub 90}Zr{sub 7}B{sub 3} amorphous alloy are studied. In the as-quenched state the medium range ordered regions are observed. The annealing at T{sub a1} leads to early stages of crystallization and nanograins with different diameter embedded in amorphous matrix are formed. At the Curie point of the amorphous phase they are magnetically decoupled and behave like superparamagnetic particles. The Curie point of the residual amorphous phase shifts towards higher temperature as compared to the as-quenched state due to the Invar like effect. The peak of the isothermal magnetic entropy changes appears at the Curie temperature of the main amorphous phase. Their values at the maximum applied field of 0.75 T equals to 0.32 J/kg K{sup -1} in the as-quenched alloy and remain almost unchanged after early stages of nanocrystallization. After the annealing at T{sub a2} the peak of the entropy changes distinctly decreases. Such behavior is ascribed to the biphasic character of the sample. The main amorphous phase and ordered one, which in some circumstances can be treated as an assembly of superparamagnetic particles, contribute to the total magnetic entropy changes.

  10. Magnetic phase diagrams and thermal equations of state of Fe7C3 and Fe3C up to the pressure-temperature conditions of Earth's core

    Science.gov (United States)

    Liu, J.; Li, Z.; Chen, B.; Li, J.; Ikuta, D.; Smith, J.; Sinogeikin, S. V.; Popov, D.; Kenney-Benson, C.

    2015-12-01

    Iron carbides Fe7C3 and Fe3C have been proposed as candidates for the dominant components of the Earth's inner core to explain its density deficit and velocity discrepancy with respect to those of pure iron at relevant pressure-temperature conditions (e.g. Chen et al., 2012; Chen et al., 2014; Gao et al., 2011). Testing the hypothesis of carbon-rich inner core requires knowledge of the thermal equations of state of the iron carbides to megabar pressures. Existing experimental data, however, are restricted to either ambient temperature or the pressures near the top of the lower mantle. In particular, the thermal expansion coefficients of the carbides under high pressures remain poorly constrained. Previous studies showed that both Fe7C3 an Fe3C are Invar-type alloys with extremely low thermal expansions in the ferromagnetic phases, and their thermal expansion coefficients more than triple across the ferromagnetic-paramagnetic transition at 1 bar (Litasov et al., 2015). On the other hand, both iron carbides experience pressure-induced spin transitions under high pressures (e.g. Chen et al., 2012; Prescher et al., 2012), but their effects on the thermal expansion are still unknown. We conducted synchrotron X-ray diffraction measurements on Fe7C3 and Fe3C up to the core's pressure and temperature conditions. High pressures up to ~140 GPa were generated by using diamond anvil cells (DAC), while high temperatures were generated using the whole-cell resistive heating device up to 700 K, and using the double-sided laser-heating system up to ~ 3500 K. The new data allow us to construct the magnetic phase diagrams of Fe7C3 and Fe3C and to assess the influences of magnetic transitions on their thermal expansion coefficients. The density profiles of appropriate magnetic phases are calculated and compared with that of the Earth's inner core to estimate its carbon content.

  11. Influence of low Co substitution on magnetoelastic properties of HoFe{sub 11}Ti intermetallic compound

    Energy Technology Data Exchange (ETDEWEB)

    Motevalizadeh, L., E-mail: lmotevali@mshdiau.ac.ir [Department of Physics, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of); Tajabor, N. [Department of Physics, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of); Sanavi Khoshnoud, D. [Department of Physics, Semnan University, Semnan 35195-363 (Iran, Islamic Republic of); Fruchart, D. [Institut. Neel, Departement MCMF, Groupe IICF, BP 166, 38042 Grenoble Cedex 9 (France); Pourarian, F. [Department of Material Science and Engineering, Carnegie Mellon University, Pittsburgh, PA 15213 (United States)

    2012-09-15

    The thermal expansion and magnetostriction of HoFe{sub 11-x}Co{sub x}Ti (x=0, 0.3, 0.7 and 1) intermetallic compounds were measured, using the strain gauge method in the temperature range 77-590 K under applied magnetic fields up to 1.5 T. Results show that for samples with x=0 and 0.3, both linear thermal expansion and linear thermal expansion coefficient exhibit anomalies below the Curie temperature. Below room temperature, the spontaneous volume magnetostriction decreases with Co content. For all compounds studied, the anisotropic magnetostriction shows similar behaviour in the measured temperature range. The magnetostriction compensation occurs above room temperature in all samples. The volume magnetostriction shows a linear dependence on the applied field and by approaching the Curie temperature this trend changes to parastrictive behaviour. The results of the spontaneous magnetostriction are discussed based on the local magnetic moment model. The contribution of magnetostriction attributed to the magnetic sublattices R and T (Fe or Co) is discussed. - Highlights: Black-Right-Pointing-Pointer Magnetostriction of HoFe{sub 11-x}Co{sub x}Ti have been measured by using strain gauge method. Black-Right-Pointing-Pointer The measurement was carried in 77-590 K under applied magnetic fields up to 1.5 T. Black-Right-Pointing-Pointer Spontaneous volume magnetostriction and Invar effect decrease with Co substitution. Black-Right-Pointing-Pointer Ho sublattice has negative contribution to spontaneous volume magnetostriction. Black-Right-Pointing-Pointer Absolute values of anisotropic magnetostriction decrease slightly with Co content.

  12. An assessment of the homogeneity of nano-crystalline Fe-Cu powders as studied by means of APT

    Energy Technology Data Exchange (ETDEWEB)

    Wille, Catharina, E-mail: cwille@ump.gwdg.de [Georg-August-University Goettingen, Institute for Materials Physics, Goettingen 37077 (Germany); Al-Kassab, Talaat [Georg-August-University Goettingen, Institute for Materials Physics, Goettingen 37077 (Germany); Choi, Pyuck-Pa [Korea Institute of Science and Technology, Nano-Materials Research Center, Seoul (Korea, Republic of); Kwon, Young-Soon [Research Center for Machine Parts and Materials Processing, University of Ulsan, Ulsan (Korea, Republic of); Kirchheim, Reiner [Georg-August-University Goettingen, Institute for Materials Physics, Goettingen 37077 (Germany)

    2009-04-15

    In this contribution the homogeneity of mechanically alloyed Fe-Cu powders for two different compositions (Fe-10 and Fe-2.5 at%Cu) has been systematically characterised by atom probe tomography. Since Fe-Cu exhibits the Invar effect, it is among the most attractive systems for technical application. Furthermore, this system is immiscible and characterised by a large positive heat of mixing. In combination with the widespread application and accessibility, this predestines Fe-Cu as a binary model alloy to elaborate the enforced nonequilibrium enhanced solubility for immiscible systems. Depending on the parameters composition and milling time, results on the extension of the solubility limit and on the homogeneity of the alloy are presented, discussed and compared to earlier works. Only for the alloy with lower Cu content and for the prolonged milling time of 50 h, chemical homogeneity of the sample as measured by the atom probe was fully reached on the nano-scale. For all other parameter combinations homogeneity could not be achieved, even for long milling times and for those samples that appear to be homogeneous via X-ray analysis. Moreover, impurities were determined, mostly stemming from the fabrication procedure. The arrangement and homogeneity of the most common impurity, oxygen, was evaluated from atom probe data for different samples. Thus, the local concentration, segregation effects and the distribution of impurities could be quantified on the nano-scale, depending on the different nominal compositions and processing parameters. Additionally, structural information could be gained employing transmission electron microscopy and diffraction measurements.

  13. A Proposed Method for the Computer-aided Discovery and Design of High-strength, Ductile Metals

    Science.gov (United States)

    Winter, Ian Stewart

    Gum Metal, a class of Ti-Nb alloys, has generated a great deal of interest in the metallurgical community since its development in 2003. These alloys display numerous novel and anomalous properties, many of which only occur after severe plastic deformation has been incurred on the material. Such properties include: super-elasticity, super-coldworkability, Invar and Elinvar behavior, high ductility, as well as high strength. The high strength of gum metal has generated particular enthusiasm as it is on the order of the predicted ideal strength of the material. Many of the properties of gum metal appear to be a direct result of tuning the composition to be near an elastic instability resulting in a high degree of elastic anisotropy. This presents an opportunity for the computer-aided discovery and design of structural materials as the ideal strength and elastic anisotropy can be approximated from the elastic constants. Two approaches are described for searching for this high ansitropy. In the first, The possibility of forming gum metal in Mg is explored by tuning the material to be near the BCC-HCP transition either by pressure or alloying with Li. The second makes use of the Materials Project's elastic constants database, which contains thousands of ordered compounds, in order to screen for gum metal candidates. By defining an elastic anisotropy parameter consistent with the behavior of gum metal and calculating it for all cubic materials in the elastic constants database several gum metal candidates are found. In order to better assess their candidacy information on the intrinsic ductility of these materials is necessary. A method is proposed for calculating the ideal strength and deformation mode of a solid solution from first-principles. In order to validate this method the intrinsic ductile-to-brittle transition composition of Ti-V systems is calculated. It is further shown that this method can be applied to the calculation of an ideal tensile yield surface.

  14. Magnetostrictions and Curie temperature measurements of (Fe-Co){sub 91-x}Mo{sub 8}Cu{sub 1}B{sub x} alloys with varying Co/Fe ratio

    Energy Technology Data Exchange (ETDEWEB)

    Vlasak, G. [Department of Metal Physics, Institute of Physics, Slovak Academy of Sciences, Dubravska cesta 9, 845 11 Bratislava (Slovakia)], E-mail: fyzivlas@savba.sk; Janickovic, D.; Svec, P. [Department of Metal Physics, Institute of Physics, Slovak Academy of Sciences, Dubravska cesta 9, 845 11 Bratislava (Slovakia)

    2008-10-15

    Amorphous rapidly quenched ribbons of (Fe-Co){sub 79}Mo{sub 8}Cu{sub 1}B{sub 12} and (Fe-Co){sub 76}Mo{sub 8}Cu{sub 1}B{sub 15} with the ratio of Co/Fe from 0 to 1 and 0 to 2, respectively, were prepared by planar flow casting. The dependence of Curie temperature T{sub C} on Co/Fe ratio was determined from temperature dependencies of sample dilatation measured using a special dilatometer designed for these materials. Due to the presence of the invar effect, it was possible to measure the spontaneous volume magnetostriction in the temperature interval between 300 K and T{sub C}, which is of the order of 10{sup -3}. Using special disc-shaped samples field dependencies of magnetostriction in parallel and perpendicular directions of the applied magnetic field were obtained by direct measurement. Subsequently, saturation magnetostriction and volume magnetostriction as well as forced magnetostriction were computed. Saturation magnetostriction {lambda}{sub S} increases with increasing Co/Fe ratio from 0 up to 15 and from 0 up to 17 ppm for both alloy systems, respectively, depending both on the Co/Fe ratio and on the shift of T{sub C} with composition. After attaining the maximal value and further increase of the Co/Fe ratio the saturation magnetostriction decreases. Both alloy systems with ratio Co/Fe=0 exhibit T{sub C} near room temperature and the system passes into paramagnetic state. T{sub C} for higher Co/Fe ratios approaches the glass transition region. In paramagnetic state the field dependencies of magnetostriction are practically linear functions of applied field and approach saturation only for high-field values.

  15. Improved Joining of Metal Components to Composite Structures

    Science.gov (United States)

    Semmes, Edmund

    2009-01-01

    Systems requirements for complex spacecraft drive design requirements that lead to structures, components, and/or enclosures of a multi-material and multifunctional design. The varying physical properties of aluminum, tungsten, Invar, or other high-grade aerospace metals when utilized in conjunction with lightweight composites multiply system level solutions. These multi-material designs are largely dependent upon effective joining techAn improved method of joining metal components to matrix/fiber composite material structures has been invented. The method is particularly applicable to equipping such thin-wall polymer-matrix composite (PMC) structures as tanks with flanges, ceramic matrix composite (CMC) liners for high heat engine nozzles, and other metallic-to-composite attachments. The method is oriented toward new architectures and distributing mechanical loads as widely as possible in the vicinities of attachment locations to prevent excessive concentrations of stresses that could give rise to delaminations, debonds, leaks, and other failures. The method in its most basic form can be summarized as follows: A metal component is to be joined to a designated attachment area on a composite-material structure. In preparation for joining, the metal component is fabricated to include multiple studs projecting from the aforementioned face. Also in preparation for joining, holes just wide enough to accept the studs are molded into, drilled, or otherwise formed in the corresponding locations in the designated attachment area of the uncured ("wet') composite structure. The metal component is brought together with the uncured composite structure so that the studs become firmly seated in the holes, thereby causing the composite material to become intertwined with the metal component in the joining area. Alternately, it is proposed to utilize other mechanical attachment schemes whereby the uncured composite and metallic parts are joined with "z-direction" fasteners. The

  16. Alignment of off-plane X-ray reflection gratings using optical light

    Science.gov (United States)

    Tutt, James; McEntaffer, Randall; Donovan, Benjamin; Schultz, Ted; DeRoo, Casey; Hertz, Edward; Allured, Ryan

    2017-08-01

    The next generation of high resolution soft X-ray spectrometers require large effective areas and high resolving capability. This can be achieved through the use of off-plane reflection gratings. X-rays will only reflect if they are incident onto a surface at a shallow graze angle; therefore, arrays of off-plane gratings are placed into the converging beam of a telescope to achieve the necessary effective area. To maintain the high resolving power of a single grating across this array, the gratings have to be very precisely aligned to one another and fanned so that they match the convergence of the telescope.Leveraging previous work that co-aligned 4 state of the art gratings into a module, 26 gratings will be co-aligned into a module that will be launched on the sub-orbital rocket WRX-R. The alignment procedure is unchanged, but improvements have been made to stabilize the setup. The alignment procedure was found to be highly temperature dependent and the opto-mechanics suffered from mechanical instabilities. To solve these issues, the new setup uses a high precision temperature control unit and a larger optical bench allowing the setup to be simplified.The alignment method is based around the generation of a light wavefront which reflects off the grating surface. This wavefront is measured using a Shack-Hartmann sensor, which allows the gratings orientation relative to the sensor normal to be found. A hexapod is then used to move the grating, allowing the grating surface to be aligned in pitch, roll and yaw. The x, y and z positions for each grating are constrained through the mechanical tolerance of the alignment mount and high precision stages. The aligned gratings are mounted into an Invar module and a theodolite is used to measure the relative position of the module to the known position of the grating.This poster discusses the improvements made to the grating alignment process and the proposed path towards producing the array of 26 co-aligned gratings that

  17. Synchrotron Diffraction Studies of Spontaneous Magnetostriction in Rare Earth Transition Metal Compounds

    International Nuclear Information System (INIS)

    Ning Yang

    2004-01-01

    Thermal expansion anomalies of R 2 Fe 14 B and R 2 Fe 17 C x (x = 0,2) (R Y, Nd, Gd, Tb, Er) stoichiometric compounds are studied with high-energy synchrotron X-ray powder diffraction using Debye-Schemer geometry in temperature range 10K to 1000K. Large spontaneous magnetostriction up to their Curie temperatures (T c ) is observed. The a-axes show relatively larger invar effects than c-axes in the R 2 Fe 14 B compounds whereas the R 2 Fe 17 C x show the contrary anisotropies. The iron sub-lattice is shown to dominate the spontaneous magnetostriction of the compounds. The contribution of the rare earth sublattice is roughly proportional to the spin magnetic moment of the rare earth in the R 2 Fe 14 B compounds but in R 2 Fe 17 C x , the rare earth sub-lattice contribution appears more likely to be dominated by the local bonding. The calculation of spontaneous magnetostrain of bonds shows that the bonds associated with Fe(j2) sites in R 2 Fe 14 B and the dumbbell sites in R 2 Fe 17 C x have larger values, which is strongly related to their largest magnetic moment and Wigner-Seitz atomic cell volume. The roles of the carbon atoms in increasing the Curie temperatures of the R 2 Fe 17 compounds are attributed to the increased separation of Fe hexagons. The R 2 Fe 17 and R 2 Fe 14 B phases with magnetic rare earth ions also show anisotropies of thermal expansion above T c . For R 2 Fe 17 and R 2 Fe 14 B the a a /a c > 1 whereas the anisotropy is reversed with the interstitial carbon in R 2 Fe 17 . The average bond magnetostrain is shown to be a possible predictor of the magnetic moment of Fe sites in the compounds. Both of the theoretical and phenomenological models on spontaneous magnetostriction are discussed and a Landau model on the spontaneous magnetostriction is proposed

  18. A deployable telescope for sub-meter resolutions from microsatellite platforms

    Science.gov (United States)

    Dolkens, D.; Kuiper, J. M.

    2017-11-01

    Sub-meter resolution imagery has become increasingly important for disaster response, defence and security applications. Earth Observation (EO) at these resolutions has long been the realm of large and heavy telescopes, which results in high image costs, limited availability and long revisit times. Using synthetic aperture technology, instruments can now be developed that can reach these resolutions using a substantially smaller launch volume and mass. To obtain a competitive MicroSatellite telescope design, a concept study was performed to develop a deployable instrument that can reach a ground resolution of 25 cm from an orbital altitude of 500 km. Two classes of instruments were analysed: the Fizeau synthetic aperture, a telescope that uses a segmented primary mirror, and a Michelson synthetic aperture, an instrument concept that combines the light of a distributed array of afocal telescopes into a final image. In a trade-off the Fizeau synthetic aperture was selected as the most promising concept for obtaining high resolution imagery from a Low Earth Orbit. The optical design of the Fizeau synthetic aperture is based on a full-field Korsch telescope that has been optimized for compactness and an excellent wavefront quality. It uses three aperture segments in a tri-arm configuration that can be folded alongside the instrument during launch. The secondary mirror is mounted on a deployable boom, further decreasing the launch volume. To maintain a high image quality while operating in the harsh and dynamic space environment, one of the most challenging obstacles that must be addressed is the very tight tolerance on the positioning of the three primary mirror segments and the secondary mirror. Following a sensitivity analysis, systems engineering budgets have been defined. The instrument concept features a robust thermo-mechanical design, aimed at reducing the mechanical uncertainties to a minimum. Silicon Carbide mirror segments, the use of Invar for the deployable

  19. Thermal stability, thermal expansion and grain-growth in exchange-coupled Fe-Pt-Ag-B bulk nanocomposite magnets

    International Nuclear Information System (INIS)

    Nicula, R.; Crisan, O.; Crisan, A.D.; Mercioniu, I.; Stir, M.; Vasiliu, F.

    2015-01-01

    Highlights: • Formation of the L10 FePt hard-magnetic phase (>90%) directly in the as-cast state. • Specific alternating hard/soft nanostructure is stable to 600 °C without grain growth. • Anisotropic and non-linear thermal expansion effects. • The FePtAgB alloy behaves like a single magnetic phase (full exchange coupling). - Abstract: Rare-earth free (RE-free) exchange coupling nanocomposite magnets are intensively studied nowadays due to their potential use in applications demanding stable high-temperature operation and corrosion resistance. In this respect, the FePt alloy system is one of the most actively addressed potential permanent magnet solutions. In FePt alloys, promising magnetic features arise from the co-existence of hard magnetic L1 0 FePt and soft magnetic L1 2 Fe 3 Pt phases emerged from the same metastable precursor. The present work deals with an in-situ temperature-resolved synchrotron radiation study of the thermal stability, thermal expansion and microstructure evolution in exchange-coupled FePtAgB alloys. The as-cast microstructural state as well as the optimized magnetic behavior are given as reference and correlated to the observed microstructural evolution with temperature. The melt-spun Fe 48 Pt 28 Ag 6 B 18 alloy ribbons were examined in situ by synchrotron X-ray powder diffraction from ambient temperature up to 600 °C. The FePt-Fe 3 Pt exchange-coupled microstructure achieved by rapid solidification is not significantly altered during the high temperature exposure. The thermal expansion of the FePt L1 0 unit cell has been found to be strongly anisotropic, being essentially an in-plane expansion which may be seen as an anisotropic invar effect. For the FePt L1 0 phase, a significant deviation from linear thermal expansion is observed at the Curie temperature T C = 477 °C. This non-linear behavior above T C is tentatively linked to a diffusion/segregation mechanism of Ag. The promising hard magnetic properties as well as the

  20. NASA Tech Briefs, December 2009

    Science.gov (United States)

    2009-01-01

    Topics include: A Deep Space Network Portable Radio Science Receiver; Detecting Phase Boundaries in Hard-Sphere Suspensions; Low-Complexity Lossless and Near-Lossless Data Compression Technique for Multispectral Imagery; Very-Long-Distance Remote Hearing and Vibrometry; Using GPS to Detect Imminent Tsunamis; Stream Flow Prediction by Remote Sensing and Genetic Programming; Pilotless Frame Synchronization Using LDPC Code Constraints; Radiometer on a Chip; Measuring Luminescence Lifetime With Help of a DSP; Modulation Based on Probability Density Functions; Ku Telemetry Modulator for Suborbital Vehicles; Photonic Links for High-Performance Arraying of Antennas; Reconfigurable, Bi-Directional Flexfet Level Shifter for Low-Power, Rad-Hard Integration; Hardware-Efficient Monitoring of I/O Signals; Video System for Viewing From a Remote or Windowless Cockpit; Spacesuit Data Display and Management System; IEEE 1394 Hub With Fault Containment; Compact, Miniature MMIC Receiver Modules for an MMIC Array Spectrograph; Waveguide Transition for Submillimeter-Wave MMICs; Magnetic-Field-Tunable Superconducting Rectifier; Bonded Invar Clip Removal Using Foil Heaters; Fabricating Radial Groove Gratings Using Projection Photolithography; Gratings Fabricated on Flat Surfaces and Reproduced on Non-Flat Substrates; Method for Measuring the Volume-Scattering Function of Water; Method of Heating a Foam-Based Catalyst Bed; Small Deflection Energy Analyzer for Energy and Angular Distributions; Polymeric Bladder for Storing Liquid Oxygen; Pyrotechnic Simulator/Stray-Voltage Detector; Inventions Utilizing Microfluidics and Colloidal Particles; RuO2 Thermometer for Ultra-Low Temperatures; Ultra-Compact, High-Resolution LADAR System for 3D Imaging; Dual-Channel Multi-Purpose Telescope; Objective Lens Optimized for Wavefront Delivery, Pupil Imaging, and Pupil Ghosting; CMOS Camera Array With Onboard Memory; Quickly Approximating the Distance Between Two Objects; Processing Images of Craters for

  1. Thermal stability, thermal expansion and grain-growth in exchange-coupled Fe-Pt-Ag-B bulk nanocomposite magnets

    Energy Technology Data Exchange (ETDEWEB)

    Nicula, R., E-mail: radu.nicula@empa.ch [Empa, Swiss Federal Laboratories for Materials Science and Technology, Advanced Materials Processing, Feuerwerkerstr. 39, CH-3602 Thun (Switzerland); Crisan, O.; Crisan, A.D.; Mercioniu, I. [National Institute for Materials Physics, P.O. Box MG-7, 077125 Bucharest-Magurele (Romania); Stir, M. [University of Berne, Department of Chemistry and Biochemistry, Freiestrasse 3, CH-3012 Berne (Switzerland); Vasiliu, F. [National Institute for Materials Physics, P.O. Box MG-7, 077125 Bucharest-Magurele (Romania)

    2015-02-15

    Highlights: • Formation of the L10 FePt hard-magnetic phase (>90%) directly in the as-cast state. • Specific alternating hard/soft nanostructure is stable to 600 °C without grain growth. • Anisotropic and non-linear thermal expansion effects. • The FePtAgB alloy behaves like a single magnetic phase (full exchange coupling). - Abstract: Rare-earth free (RE-free) exchange coupling nanocomposite magnets are intensively studied nowadays due to their potential use in applications demanding stable high-temperature operation and corrosion resistance. In this respect, the FePt alloy system is one of the most actively addressed potential permanent magnet solutions. In FePt alloys, promising magnetic features arise from the co-existence of hard magnetic L1{sub 0} FePt and soft magnetic L1{sub 2} Fe{sub 3}Pt phases emerged from the same metastable precursor. The present work deals with an in-situ temperature-resolved synchrotron radiation study of the thermal stability, thermal expansion and microstructure evolution in exchange-coupled FePtAgB alloys. The as-cast microstructural state as well as the optimized magnetic behavior are given as reference and correlated to the observed microstructural evolution with temperature. The melt-spun Fe{sub 48}Pt{sub 28}Ag{sub 6}B{sub 18} alloy ribbons were examined in situ by synchrotron X-ray powder diffraction from ambient temperature up to 600 °C. The FePt-Fe{sub 3}Pt exchange-coupled microstructure achieved by rapid solidification is not significantly altered during the high temperature exposure. The thermal expansion of the FePt L1{sub 0} unit cell has been found to be strongly anisotropic, being essentially an in-plane expansion which may be seen as an anisotropic invar effect. For the FePt L1{sub 0} phase, a significant deviation from linear thermal expansion is observed at the Curie temperature T{sub C} = 477 °C. This non-linear behavior above T{sub C} is tentatively linked to a diffusion/segregation mechanism of Ag

  2. Improved wavelengths for Fe V and Ni V for analysis of spectra of white dwarf stellar stars

    Science.gov (United States)

    Ward, Jacob; Nave, Gillian

    2015-08-01

    A recent paper by J.C. Berengut et al. tests for a potential variation in the fine-structure constant, α, in the presence of a high gravitational field through spectral analysis of white-dwarf stars. The spectrum of G191-B2B has prominent Fe V and Ni V lines in the vacuum ultraviolet (VUV) region that were used to determine any variation in α via observed shifts in their wavelengths. Although no strong evidence for a variation was found, the authors did find a difference between values obtained for Fe V and Ni V that were indicative of a problem with the laboratory wavelengths. The laboratory wavelengths dominate the uncertainty of the measured variation, so improved values would tighten the constraints on the variation of α.We have re-measured the spectra of Fe V and Ni V spectra in the VUV in order to reduce the wavelength uncertainties and put the two spectra on a consistent wavelength scale. The spectra were produced by a sliding spark light source with electrodes made of invar, an iron nickel alloy. Spectra of Fe V and Ni V were obtained using peak currents of 750-2000 A. The spectra were recorded using the NIST Normal Incidence Vacuum Spectrograph with phosphor image plates and photographic plates as detectors. Wavelengths from 1100 Å to 1800 Å were covered in a single exposure. A spectrum of a Pt/Ne hollow cathode lamp was also recorded for wavelength calibration.The spectra recorded on photographic plates are better resolved than the phosphor image plate spectra and are being measured in two ways. The first measures the positions of the spectral lines on a comparator, traditionally used to measure many archival spectra at NIST. The second uses a commercial image scanner to obtain a digital image of the plate that can be analyzed using line fitting software. Preliminary analysis of these spectra indicates that the literature values of the Fe V and Ni V wavelengths are not on the same scale and differ from our new measurements by up to 0.02 Å in some

  3. Developing magnetofunctionality: Coupled structural and magnetic phase transition in AlFe{sub 2}B{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, L.H., E-mail: lhlewis@neu.edu [Department of Chemical Engineering, Northeastern University, Boston, MA 02115 (United States); Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA 02115 (United States); George J. Kostas Research Institute for Homeland Security, Northeastern University, Burlington, MA (United States); Barua, R., E-mail: radhika.barua@gmail.com [Department of Chemical Engineering, Northeastern University, Boston, MA 02115 (United States); Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA 02115 (United States); George J. Kostas Research Institute for Homeland Security, Northeastern University, Burlington, MA (United States); Lejeune, B. [Department of Chemical Engineering, Northeastern University, Boston, MA 02115 (United States); George J. Kostas Research Institute for Homeland Security, Northeastern University, Burlington, MA (United States)

    2015-11-25

    Understanding correlations between crystal structure and magnetism is key to tuning the response of magnetic materials systems that exhibit large functional effects in response to small excursions in magnetic field or strain. To this end, temperature-dependent structure-magnetic property correlations are reported in samples of AlFe{sub 2}B{sub 2} with the orthorhombic AlMn{sub 2}B{sub 2}-type layered structure as it traverses a thermally-hysteretic first-order magnetic phase change at a transition temperature of T{sub t} = 280 K. Temperature-dependent x-ray diffraction carried out in the temperature range 200 K ≤ T ≤ 298 K reveals that the a and b lattice parameters increase by 0.2% and 0.1% respectively upon heating, while the c lattice parameter decreases by 0.3%, providing a conserved unit cell volume through T{sub t}. A very small volumetric thermal expansion coefficient 4.4 × 10{sup −6}/K is determined in this temperature range that is one order of magnitude smaller than that of aluminum and only slightly larger than that of Invar. The latent heat of transformation associated with this magnetostructural phase transformation is determined as 4.4 J/g, similar to that of other magnetostructural materials. Overall, these features confirm a first-order thermodynamic phase change in the AlFe{sub 2}B{sub 2} system that emphasizes strong coupling between the magnetic spins and the lattice to support potential magnetofunctional applications for energy transformation and harvesting. - Highlights: • AlFe{sub 2}B{sub 2} undergoes a first-order magnetostructural transformation near room temperature. • The AlFe{sub 2}B{sub 2} Curie transition is thermally hysteretic and magnetic field dependent. • XRD reveals a volume-conserved change in the lattice constants of the AlFe{sub 2}B{sub 2} unit cell. • The latent heat of the magnetostructural transformation is determined as 4.4 J/g. • Results emphasize strong coupling between the magnetic spins and the lattice

  4. Thin-film thermomechanical sensors embedded in metallic structures

    Science.gov (United States)

    Golnas, Anastasios M.

    2000-10-01

    The ability to monitor in real time the thermo-mechanical responses of tools, equipment, and structural components has been very appealing to the aerospace, automotive, drilling, and manufacturing industries. So far, the challenge has been to instrument the tools, equipment, or structural components with a number of sensors in an economical way and also protect the sensors from the environment which the tools, etc. are exposed to. In this work, a sequence of manufacturing processes that can be used to build thin-film temperature and strain sensors on internal surfaces of metallic structures is proposed and demonstrated. The use of thin-film techniques allows the parallel fabrication of sensor arrays, whereas a layered manufacturing scheme permits the creation of sensors on the internal surfaces of metallic parts and their subsequent embedding. Thin-film sensors are deposited on an aluminum oxide film, which is grown on a stainless steel substrate. The oxide is deposited by reactive sputtering. The sensors are sputter-deposited from alloy targets, shaped via micromachining and partially covered with a passivation layer of aluminum oxide. The thin-film structure is then covered by two protective electroplated layers of copper and nickel for protection during the deposition of the embedding layers. Embedding is accomplished by using a high-power infrared laser to melt an invar powder bed on top of the protective layers. Among the issues that emerged during the definition of the fabrication sequence were: the long-term stability of reactive deposition, the presence of pinholes in the dielectric layers, the optimal combination of materials and thickness of the protective layers, the bonding at the various interfaces, and the heat input and residual stresses resulting from the high-temperature embedding process. Finally, a finite element model was constructed in order to simulate the high-temperature embedding process. The heat transfer analysis performed on the model

  5. Gluing interface qualification test results and gluing process development of the EUCLID near-infrared spectro-photometer optical assembly

    Science.gov (United States)

    Mottaghibonab, A.; Thiele, H.; Gubbini, E.; Dubowy, M.; Gal, C.; Mecsaci, A.; Gawlik, K.; Vongehr, M.; Grupp, F.; Penka, D.; Wimmer, C.; Bender, R.

    2016-07-01

    The Near Infrared Spectro-Photometer Optical assembly (NIOA) of EUCLID satellite requires high precision large lens holders with different lens materials, shapes and diameters. The aspherical lenses are glued into their separate CTE matched lens holder. The gluing of the lenses in their holder with 2K epoxy is selected as bonding process to minimize the stress in the lenses to achieve the required surface form error (SFE) performance (32nm) and lens position stability (+/-10μm) due to glue shrinkage. Adhesive shrinkage stress occurs during the glue curing at room temperature and operation in cryogenic temperatures, which might overstress the lens, cause performance loss, lens breakage or failure of the gluing interface. The selection of the suitable glue and required bonding parameters, design and qualification of the gluing interface, development and verification of the gluing process was a great challenge because of the low TRL and heritage of the bonding technology. The different material combinations (CaF2 to SS316L, LF5G15 and S-FTM16 to Titanium, SUPRASIL3001 to Invar M93), large diameter (168mm) and thin edge of the lenses, cryogenic nonoperational temperature (100K) and high performance accuracy of the lenses were the main design driver of the development. The different coefficients of thermal expansion (CTE) between lens and lens holder produce large local mechanical stress. As hygroscopic crystal calcium fluoride (CaF2) is very sensitive to moisture therefore an additional surface treatment of the gluing area is necessary. Extensive tests e.g glue handling and single lap shear tests are performed to select the suitable adhesive. Interface connection tests are performed to verify the feasibility of selected design (double pad design), injection channel, the roughness and treatment of the metal and lens interfaces, glue thickness, glue pad diameter and the gluing process. CTE and dynamic measurements of the glue, thermal cycling, damp- heat, connection

  6. Multifunctional, High-Temperature Nanocomposites

    Science.gov (United States)

    Connell, John W.; Smith, Joseph G.; Siochi, Emilie J.; Working, Dennis C.; Criss, Jim M.; Watson, Kent A.; Delozier, Donavon M.; Ghose, Sayata

    2007-01-01

    microscopy shows splits in the walls of the MWCNTs but no catastrophic breakage of tubes. To further assess processing characteristics prior to scale-up, samples containing 10, 15, and 20 weight-percent of MWCNTs were processed through a laboratory melting extruder. HRSEM of the extruded fibers shows significant alignment of MWCNTs in the flow direction (see figure). For the samples containing 20 weight-percent of MWCNTs, difficulties were encountered during feeding, and the temperature of a rotor in the extruder rose to 245 C because of buildup of frictional heat; this indicates that materials of this type having MWCNT concentrations .20 weight- percent may not be melt-processable. On the basis of the results from the foregoing characterizations, samples containing 10, 15, and 20 weight-percent of MWCNTs were scaled up to masses of .300 g and used to make specimens having dimensions of 10.2 by 15.2 by 0.32 cm. These specimens were molded by (1) injecting the mixtures, at temperatures between 260 and 280 C, into a tool made of the low-thermal-expansion alloy InvarR and then (2) curing for 1 hour at 371 C. The tool was designed to impart shear during the injection process in an attempt to achieve some alignment of the MWCNTs in the flow direction.

  7. Photogrammetric Metrology for the James Webb Space Telescope Integrated Science Instrument Module

    Science.gov (United States)

    Nowak, Maria; Crane, Allen; Davila, Pam; Eichhorn, William; Gill, James; Herrera, Acey; Hill, Michael; Hylan, Jason; Jetten, Mark; Marsh, James; hide

    2007-01-01

    The James Webb Space Telescope (JWST) is a 6.6m diameter, segmented, deployable telescope for cryogenic IR space astronomy (approximately 40K). The JWST Observatory architecture includes the Optical Telescope Element and the Integrated Science Instrument Module (ISIM) element that contains four science instruments (SI) including a Guider. The ISM optical metering structure is a roughly 2.2x1.7x2.2m, asymmetric frame that is composed of carbon fiber and resin tubes bonded to invar end fittings and composite gussets and clips. The structure supports the SIs, isolates the SIs from the OTE, and supports thermal and electrical subsystems. The structure is attached to the OTE structure via strut-like kinematic mounts. The ISIM structure must meet its requirements at the approximately 40K cryogenic operating temperature. The SIs are aligned to the structure's coordinate system under ambient, clean room conditions using laser tracker and theodolite metrology. The ISIM structure is thermally cycled for stress relief and in order to measure temperature-induced mechanical, structural changes. These ambient-to-cryogenic changes in the alignment of SI and OTE-related interfaces are an important component in the JWST Observatory alignment plan and must be verified. We report on the planning for and preliminary testing of a cryogenic metrology system for ISIM based on photogrammetry. Photogrammetry is the measurement of the location of custom targets via triangulation using images obtained at a suite of digital camera locations and orientations. We describe metrology system requirements, plans, and ambient photogrammetric measurements of a mock-up of the ISIM structure to design targeting and obtain resolution estimates. We compare these measurements with those taken from a well known ambient metrology system, namely, the Leica laser tracker system. We also describe the data reduction algorithm planned to interpret cryogenic data from the Flight structure. Photogrammetry was

  8. Synchrotron Diffraction Studies of Spontaneous Magnetostriction in Rare Earth Transition Metal Compounds

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ning [Iowa State Univ., Ames, IA (United States)

    2004-12-19

    Thermal expansion anomalies of R2Fe14B and R2Fe17Cx (x = 0,2) (R = Y, Nd, Gd, Tb, Er) stoichiometric compounds are studied with high-energy synchrotron X-ray powder diffraction using Debye-Schemer geometry in temperature range 10K to 1000K. Large spontaneous magnetostriction up to their Curie temperatures (Tc) is observed. The a-axes show relatively larger invar effects than c-axes in the R2Fe14B compounds whereas the R2Fe17Cx show the contrary anisotropies. The iron sub-lattice is shown to dominate the spontaneous magnetostriction of the compounds. The contribution of the rare earth sublattice is roughly proportional to the spin magnetic moment of the rare earth in the R2Fe14B compounds but in R2Fe17Cx, the rare earth sub-lattice contribution appears more likely to be dominated by the local bonding. The calculation of spontaneous magnetostrain of bonds shows that the bonds associated with Fe(j2) sites in R2Fe14B and the dumbbell sites in R2Fe17Cx have larger values, which is strongly related to their largest magnetic moment and Wigner-Seitz atomic cell volume. The roles of the carbon atoms in increasing the Curie temperatures of the R2Fe17 compounds are attributed to the increased separation of Fe hexagons. The R2Fe17 and R2Fe14B phases with magnetic rare earth ions also show anisotropies of thermal expansion above c. For R2Fe17 and R2Fe14B the a a/a c > 1 whereas the anisotropy is reversed with the interstitial carbon in R2Fe17. The average bond magnetostrain is shown to be a possible predictor of the magnetic moment of Fe sites in the compounds. Both of the theoretical and

  9. The Newcomb & Michelson Velocity of Light Experiments

    Science.gov (United States)

    Carter, W. E.

    2002-05-01

    velocity of light in vacuum. First, a value of 299,860 km/sec based only on observations made in 1882, which he preferred because he thought that they were less affected by systematic errors. Second, 299,810 km/sec based on a weighted combination of all the observations, which proved to be the more accurate value. Newcomb suggested changes to the design of the instrumentation to improve the visibility of the return image, and concluded his report by pointing out that \\"\\ in the Rocky Mountains or the Sierra Nevada no difficulty would be found in finding stations at which a return ray could be received from a distance of 30, 40, or even 50 kilometers, with little more dispersion and loss than at a distance of 4 kilometers through the air of less favored regions.\\"\\ More than 40 years later, from 1924 to 1927, Michelson fulfilled Newcombś vision by measuring the velocity of light over a 35 kilometer line between the Carnegie Institution of Washington's Mt. Wilson Observatory and Mount San Antonio, in the San Gabriel mountains of California. The USC&GS once again determined the distance between the rotating and fixed reflector, using a baseline measured with their newly acquired "invar" tapes, and triangulation. The rotating mirror had eight faces, and was made of steel to withstand the centrifugal force at 528 rev/sec. Michelson obtained a value of for the velocity of light in vacuum of 299,796 ñ 4 k/sec, compared to the value of 299,792.458 k/sec accepted today. History books do not record it as so, but Michelson's Mt. Wilson experiment might more rightly be considered the conclusion of the Newcomb-Michelson velocity of light experiments begun two decades earlier in Washington D.C.

  10. Developing and Characterizing Bulk Metallic Glasses for Extreme Applications

    Science.gov (United States)

    Roberts, Scott Nolan

    characterized. Ti 6Al-4V to pure vanadium was chosen for its combination of high strength and light weight on one end, and high melting point on the other. It was inspected by cross-sectional x-ray diffraction, and only the anticipated phases were present. 304L stainless steel to Invar 36 was created in both pillar and as a radial gradient. It combines strength and weldability along with a zero coefficient of thermal expansion material. Only the austenite phase is found to be present via x-ray diffraction. Coefficient of thermal expansion is measured for four compositions, and it is found to be tunable depending on composition.