WorldWideScience

Sample records for dilatometers

  1. Dilatometer for use in tensile tests

    NARCIS (Netherlands)

    Coumans, W.J.; Heikens, D.

    1980-01-01

    An accurate dilatometer is described which permits simultaneous and automatic recording of sample vol. change during tensile tests on a com. tester. Liq. displacements in the dilatometer capillary, which correspond to vol. changes of the sample, are detected by a cond. meter. Tensile load is

  2. Design, fabrication and operation of the LVDT based vertical dilatometer

    International Nuclear Information System (INIS)

    Manoj, N.; Kerkar, A.S.; Mathews, M.D.; Gautam, J.K.; Tyagi, A.K.; Thomas, K.C.

    2005-07-01

    This report provides the details of a dilatometer developed in-house to measure thermal expansion from room temperature to 1173 K. The instrument was designed, fabricated and tested for its satisfactory performance by analyzing the thermal expansion properties of several materials up to a maximum temperature of 1123 K. One of the important feature in this design is that, the instrument has been fabricated by using all indigenously available components. The sample loading and initial zero adjustment procedure has been made very simple in this design. The software for furnace temperature programming and control, data collection, data processing and plotting of the graph has also been developed. Provision for carrying out the measurements in vacuum as well as flowing gas have been provided. (author)

  3. Microwave differential dilatometer measures 10 - 12 m, at 1 Hz

    Science.gov (United States)

    Aschero, G.; Mango, F.; Gizdulich, P.

    1996-12-01

    To check and measure the converse piezoelectric effect in bone samples, we had to detect displacements in the range of 1-100 pm with three kinds of restrictions: (1) the biological nature of the samples imposes severe limits in selecting a suitable device and method; (2) such a method has to take into account some clinical applications to which the experiment is devoted; (3) the piezoelectric behavior of bone samples is particularly interesting at low frequencies, around 1 Hz. For such reasons we modified an existing dilatometer based on a microwave differential spectrometer. A 14 GHz klystron, linearly modulated in frequency by a triangular 50 Hz voltage applied to the repeller, is connected, via magic T, to two identical cavities tunable around 14 GHz and whose resonance curves are recorded by crystal detectors. When one of the two cavities changes its height according to the length variations of the sample, its resonance frequency varies resulting in a shift of the resonant curve with respect to the resonance curve of the other cavity acting as reference. The comparison between the cavities' responses is performed by a pulse technique transforming the frequency shifts into time intervals, that are then converted into dc voltages. The differential character of this measurement avoids the need for the microwave source stabilization. The relative shift in frequency is measured with an accuracy better than 500 Hz. This accuracy allows us to measure displacements smaller than 7 nm in the cavity's height. After 2 h of warmup, thanks to the differential arrangement of the system, thermal or other drifts are not detectable within a lapse of time of 12 h. This feature allows coherent signal averaging over long periods. With a piezoelectric ceramic stack moving 100 pm in square wave fashion at 50 mHz we found that the signal to noise ratio was 20 dB after 1000 cycles of signal averaging, when our bandpass filter was tuned at 1 Hz. In conclusion, this system can detect

  4. The JPL Cryogenic Dilatometer: Measuring the Thermal Expansion Coefficient of Aerospace Materials

    Science.gov (United States)

    Halverson, Peter G.; Dudick, Matthew J.; Karlmann, Paul; Klein, Kerry J.; Levine, Marie; Marcin, Martin; Parker, Tyler J.; Peters, Robert D.; Shaklan, Stuart; VanBuren, David

    2007-01-01

    This slide presentation details the cryogenic dilatometer, which is used by JPL to measure the thermal expansion coefficient of materials used in Aerospace. Included is a system diagram, a picture of the dilatometer chamber and the laser source, a description of the laser source, pictures of the interferometer, block diagrams of the electronics and software and a picture of the electronics, and software. Also there is a brief review of the accurace.error budget. The materials tested are also described, and the results are shown in strain curves, JPL measured strain fits are described, and the coefficient of thermal expansion (CTE) is also shown for the materials tested.

  5. A dilatometer to measure the influence of cooling rate and melt shearing on specific volume

    NARCIS (Netherlands)

    van der Beek, M.H.E.; Peters, G.W.M.; Meijer, H.E.H.

    2005-01-01

    We developed a dilatometer to investigate the specific volume of polymers as a function of pressure (to 100 MPa), temperature (to 260 oC), cooling rate (to 80 C/s), and shear rate (to 77 1/s). The dilatometeris based on the principle of con¯ned compression and comprises of a pressure cell used in

  6. Next generation dilatometer for highest accuracy thermal expansion measurement of ZERODUR®

    Science.gov (United States)

    Jedamzik, Ralf; Engel, Axel; Kunisch, Clemens; Westenberger, Gerhard; Fischer, Peter; Westerhoff, Thomas

    2015-09-01

    In the recent years, the ever tighter tolerance for the Coefficient of thermal expansion (CTE) of IC Lithography component materials is requesting significant progress in the metrology accuracy to determine this property as requested. ZERODUR® is known for its extremely low CTE between 0°C to 50°C. The current measurement of the thermal expansion coefficient is done using push rod dilatometer measurement systems developed at SCHOTT. In recent years measurements have been published showing the excellent CTE homogeneity of ZERODUR® in the one-digit ppb/K range using these systems. The verifiable homogeneity was limited by the CTE(0°C, 50°C) measurement repeatability in the range of ± 1.2 ppb/K of the current improved push rod dilatometer setup using an optical interferometer as detector instead of an inductive coil. With ZERODUR® TAILORED, SCHOTT introduced a low thermal expansion material grade that can be adapted to individual customer application temperature profiles. The basis for this product is a model that has been developed in 2010 for better understanding of the thermal expansion behavior under given temperature versus time conditions. The CTE behavior predicted by the model has proven to be in very good alignment with the data determined in the thermal expansions measurements. The measurements to determine the data feeding the model require a dilatometer setup with excellent stability and accuracy for long measurement times of several days. In the past few years SCHOTT spent a lot of effort to drive a dilatometer measurement technology based on the push rod setup to its limit, to fulfill the continuously demand for higher CTE accuracy and deeper material knowledge of ZERODUR®. This paper reports on the status of the dilatometer technology development at SCHOTT.

  7. A new method for determining the Curie temperature using a dilatometer

    International Nuclear Information System (INIS)

    Verma, A; Sundararaman, M; Singh, J B; Nalawade, S A

    2010-01-01

    Dilatometry is a tool used for the study of dimensional changes in materials as a function of temperature and also to identify phase transformations including magnetic transformations. In this paper, we describe two new methods that can be employed in an inductively heated dilatometer to determine the Curie temperature in metallic ferromagnetic materials. These methods are based on the fundamental magnetic properties of materials such as hysteresis loss and anomalous thermal conductivity changes near the Curie point. These methods have been used to determine the Curie point in nickel, iron and Co–5 at% Ni alloy. The values obtained match well with those reported in the literature. The effects of the geometry of the specimen and of the push-rod material on the measurement sensitivity of the transition temperature have been discussed

  8. Magmatic processes evidenced by borehole dilatometer data at Campi Flegrei, Italy.

    Science.gov (United States)

    Di Lieto, Bellina; Romano, Pierdomenico; Scarpa, Roberto; Orazi, Massimo

    2017-04-01

    Since spring 2004 a joint research project (AMRA, UniSa, INGV) has been developed in Italy to install borehole strainmeters aimed at enhanced INGV monitoring systems. Six Sacks-Evertson dilatometers were installed around Campi Flegrei and Vesuvius during 2004-2005, and in 2008 these were supplemented by two arrays of long-baseline underground water tube tiltmeters. Renewed activity started since 2004-2005, characterized by a low rate of vertical displacement, amounting initially to a few cm/year. Recent deformation in the Campi Flegrei caldera is dominated by aseismic inflation, interrupted by minor transient aseismic reversals in rate. These are typically below the noise level or are poorly sampled by the low sampling frequency of most geodetic techniques, but can be quantified relatively easily using high sensitivity strainmeters and tiltmeters. These instruments provide coherent views of deformation at several different time scales capturing reversals in rate with periods from minutes to months. Monotonic uplift episodes have been recorded with durations of several weeks to a few years. During the summer of 2006 a long term strain episode related to an increase of CO2 emission, evidenced by borehole tiltmeters and continuous GPS sensors, has been observed by the borehole dilatometers array. This strain episode preceded caldera microseismic activity by few months, as was also observed during the 1982 period of unrest. Other aseismic slip episodes were recorded in October 2006 and in March 2010, several minutes before the most significant seismic swarms (VT and/or LP events) occurred after the 1982-1984 uplift. The time scale of these transient strain events lasted less than one hour, putting further constraints on the origin of ground uplifts at Campi Flegrei. Their locations are compatible with the source inferred from long term deformation signals, at about 4 km depth beneath Pozzuoli. The current array provides us with a glimpse of the potential utility of a

  9. A Simple Method for Determining Thermal Expansion Coefficient of Solid Materials with a Computer-aided Electromagnetic Dilatometer Measuring System

    Directory of Open Access Journals (Sweden)

    Z. EZZOUINE

    2015-07-01

    Full Text Available In this study, we present a newly designed electromagnetic dilatometer with micrometer accuracy for the measurement of the coefficient of thermal expansion of a solid in the 30 °C – 96 °C temperature range .The device has a graphical user interface to view real time data measurement. Iron and copper were subjected to temperature change in the thermal expansion experiment causing them to expand linearly. The voltage delivered in the electromagnetic dilatometer system, which includes the information about linear expansion and temperature change were transferred to a computer via a data acquisition card, presented by a program created in the LabVIEW environment, and the amount of linear expansion was detected in real time. The minimal change in length of the sample that can be resolved is 5µm, which yields the sensitivity comprised between 10-4 µm and 10-5 µm. In order to calibrate the electromagnetic dilatometer, thermal expansion coefficients of copper and Iron have been measured. By this technique, the thermal expansion coefficient can be determined with an acceptable accuracy. The present results appear also to agree well with those reported previously in the literature.

  10. A high-stability non-contact dilatometer for low-amplitude temperature-modulated measurements

    Energy Technology Data Exchange (ETDEWEB)

    Luckabauer, Martin; Sprengel, Wolfgang; Würschum, Roland [Institute of Materials Physics, Graz University of Technology, A-8010 Graz (Austria)

    2016-07-15

    Temperature modulated thermophysical measurements can deliver valuable insights into the phase transformation behavior of many different materials. While especially for non-metallic systems at low temperatures numerous powerful methods exist, no high-temperature device suitable for modulated measurements of bulk metallic alloy samples is available for routine use. In this work a dilatometer for temperature modulated isothermal and non-isothermal measurements in the temperature range from room temperature to 1300 K is presented. The length measuring system is based on a two-beam Michelson laser interferometer with an incremental resolution of 20 pm. The non-contact measurement principle allows for resolving sinusoidal length change signals with amplitudes in the sub-500 nm range and physically decouples the length measuring system from the temperature modulation and heating control. To demonstrate the low-amplitude capabilities, results for the thermal expansion of nickel for two different modulation frequencies are presented. These results prove that the novel method can be used to routinely resolve length-change signals of metallic samples with temperature amplitudes well below 1 K. This high resolution in combination with the non-contact measurement principle significantly extends the application range of modulated dilatometry towards high-stability phase transformation measurements on complex alloys.

  11. The 1996-2009 borehole dilatometer installations, operation, and maintenance at sites in Long Valley Caldera, CA

    Science.gov (United States)

    Myren, Glenn; Johnston, Malcolm; Mueller, Robert

    2011-01-01

    High seismicity levels with accelerating uplift (under the resurgent dome) in Long Valley caldera in the eastern Sierra Nevada from 1989 to 1997, triggered upgrades to dilational strainmeters and other instrumentation installed in the early 1980's following a series of magnitude 6 earthquakes. This included two additional high-resolution borehole strainmeters and replacement of the failed strainmeter at Devil's Postpile. The purpose of the borehole-monitoring network is to monitor crustal deformation and other geophysical parameters associated with volcanic intrusions and earthquakes in the Long Valley Caldera. Additional instrumentation was added at these sites to improve the capability of providing continuous monitoring of the magma source under the resurgent dome. Sites were selected in regions of hard crystalline rock, where the expected signals from magmatic activity were calculated to be a maximum and the probability of an earthquake of magnitude 4 or greater is large. For the most part, the dilatometers were installed near existing arrays of surface tiltmeters, seismometers, level line, and GPS arrays. At each site, attempts are made to separate tectonic and volcanic signals from known noise sources in each instrument type. Each of these sites was planned to be a multi-parameter monitoring site, which included measurements of 3-component seismic velocity and acceleration, borehole strain, tilt, pore pressure and magnetic field. Using seismicity, geophysical knowledge, geologic and topographic maps, and geologists recommendations, lists of preliminary sites were chosen. Additional requirements were access, and telemetry constraints. When the final site choice was made, a permit was obtained from the U.S. Forest Service. Following this selection process, two new borehole sites were installed on the north and south side of the Long Valley Caldera in June of 1999. One site was located near Big Spring Campground to the east of Crestview. The second site was

  12. Method for analyzing passive silicon carbide thermometry with a continuous dilatometer to determine irradiation temperature

    Science.gov (United States)

    Campbell, Anne A.; Porter, Wallace D.; Katoh, Yutai; Snead, Lance L.

    2016-03-01

    Silicon carbide is used as a passive post-irradiation temperature monitor because the irradiation defects will anneal out above the irradiation temperature. The irradiation temperature is determined by measuring a property change after isochronal annealing, i.e., lattice spacing, dimensions, electrical resistivity, thermal diffusivity, or bulk density. However, such methods are time-consuming since the steps involved must be performed in a serial manner. This work presents the use of thermal expansion from continuous dilatometry to calculate the SiC irradiation temperature, which is an automated process requiring minimal setup time. Analysis software was written that performs the calculations to obtain the irradiation temperature and removes possible user-introduced error while standardizing the analysis. This method has been compared to an electrical resistivity and isochronal annealing investigation, and the results revealed agreement of the calculated temperatures. These results show that dilatometry is a reliable and less time-intensive process for determining irradiation temperature from passive SiC thermometry.

  13. Development Of High-Resolution Mechanical Spectroscopy, HRMS: Status And Perspectives. HRMS Coupled With A Laser Dilatometer

    Directory of Open Access Journals (Sweden)

    Magalas L.B.

    2015-09-01

    Full Text Available Recent achievements in the development of low-frequency high-resolution mechanical spectroscopy (HRMS are briefly reported. It is demonstrated that extremely low values of the loss angle, ϕ, (tanϕb = 1×10−5 can be measured as a function of frequency, and the precision in estimation of the dynamic modulus is better than 1×10−5 in arbitrary units. Three conditions must be fulfilled to obtain high resolution in subresonant and resonant mechanical loss measurements: (1 noise in stress and elastic strain signals must be lower than 70 dB, (2 high quality of stress and strain signals must be tested both in the frequency- and time-domains, and (3 the estimation of the mechanical loss and modulus must be verified by at least two different computing methods operating in the frequency- and time-domains. It is concluded that phase measurements in the subresonant domain are no longer determined by precision in estimation of the loss angle. Recent developments in high-resolution resonant mechanical loss measurements stem from the application of advanced nonparametric and parametric computing methods and algorithms to estimate the logarithmic decrement and the elastic modulus from exponentially damped free decaying oscillations embedded in experimental noise.

  14. Linear thermal expansion coefficient measurement technology in hot cell

    International Nuclear Information System (INIS)

    Park, Dae Gyu; Choo, Yong Sun; Ahn, Sang Bok; Hong, Kwon Pyo; Lee, K. S.

    1998-06-01

    To establish linear thermal expansion coefficient measurement technology in hot cell, we reviewed and evaluated various measuring technology by paper and these were compared with the data produced with pre-installed dilatometer in hot cell. Detailed contents are as follows; - The theory of test. - Review of characteristics for various measurement technology and compatibility with hot cell. - Review of standard testing regulations(ASTM). - System calibration of pre-installed dilatometer. - Performance test of pre-installed dilatometer. (author). 12 refs., 15 tabs., 8 figs

  15. Electric Field Induced Strain in Electrostrictive Polymers Under High Hydrostatic Pressure - System Development and Material Characterization

    National Research Council Canada - National Science Library

    Zhang, Q

    2000-01-01

    ... of (i) developing a high performance piezo-bimorph based dilatometer which can be used to characterize the electric field induced strain response in polymer films under high hydrostatic pressure, (ii...

  16. Thermal expansion of epoxy-fiberglass composite specimens

    International Nuclear Information System (INIS)

    McElroy, D.L.; Weaver, F.J.; Bridgman, C.

    1986-01-01

    The thermal expansion behavior of three epoxy-fiberglass composite specimens was measured from 20 to 120 0 C (70 to 250 0 F) using a fused quartz push-rod dilatometer. Billets produced by vacuum impregnating layers of two types of fiberglass cloth with an epoxy resin were core-drilled to produce cylindrical specimens. These were used to study expansion perpendicular and parallel to the fiberglass layers. The dilatometer is held at a preselected temperature until steady-state is indicated by stable length and temperature data. Before testing the composite specimens, a reliability check of the dilatometer was performed using a copper secondary standard. This indicated thermal expansion coefficient (α) values within +-2% of expected values from 20 to 200 0 C

  17. Measurement of the Thermal Expansion Coefficient for Ultra-High Temperatures up to 3000 K

    Science.gov (United States)

    Kompan, T. A.; Kondratiev, S. V.; Korenev, A. S.; Puhov, N. F.; Inochkin, F. M.; Kruglov, S. K.; Bronshtein, I. G.

    2018-03-01

    The paper is devoted to a new high-temperature dilatometer, a part of the State Primary Standard of the thermal expansion coefficient (TEC) unit. The dilatometer is designed for investigation and certification of materials for TEC standards in the range of extremely high temperatures. The critical review of existing methods of TEC measurements is given. Also, the design, principles of operation and metrological parameters of the new device are described. The main attention is paid to the system of machine vision that allows accurate measurement of elongation at high temperatures. The results of TEC measurements for graphite GIP-4, single crystal Al2O3, and some other materials are also presented.

  18. Thermodynamic properties of CuCr2S4 solid solutions in Cusub(1/2)Msub(1/2)Crsub(2)Ssub(4) (M - Ga, In)

    International Nuclear Information System (INIS)

    Titov, V.V.; Kesler, Ya.A.; Shelkotunov, V.A.; Gordeev, I.V.; Tret'yakov, Yu.D.

    1985-01-01

    By means of an adiabatic calorimeter and quartz dilatometer for CuCr 2 S 4 in Cusub(1/2)Msub(1/2)Crsub(2)Ssub(4) (M-Ga, In) temperature dependences of heat capacity are determined. The contribution of various components into heat capacity is estimated, thermodynamic parameters of magnetic transformation are calculated

  19. Thermodynamic properties of CuCr/sub 2/S/sub 4/ solid solutions in Cusub(1/2)Msub(1/2) Crsub(2)Ssub(4) (M - Ga, In)

    Energy Technology Data Exchange (ETDEWEB)

    Titov, V.V.; Kesler, Ya.A.; Shelkotunov, V.A.; Gordeev, I.V.; Tret' yakov, Yu.D.

    1985-04-01

    By means of an adiabatic calorimeter and quartz dilatometer for CuCr/sub 2/S/sub 4/ in Cusub(1/2)Msub(1/2) Crsub(2)Ssub(4) (M-Ga, In) temperature dependences of heat capacity are determined. The contribution of various components into heat capacity is estimated, thermodynamic parameters of magnetic transformation are calculated.

  20. Influence of shear flow on the specific volume and the crystalline morphology of isotactic polypropylene

    NARCIS (Netherlands)

    van der Beek, M.H.E.; Peters, G.W.M.; Meijer, H.E.H.

    2006-01-01

    The influence of shear flow on the temperature evolution of the specific volume and the crystalline morphology of two iPP's, differing in weight-averaged molar mass w, was investigated at nonisothermal conditions and elevated pressures, using a custom-designed dilatometer. These conditions are

  1. HETEK - Control of Early Age Cracking in Concrete

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Christensen, Søren Lolk; Dela, Birgitte Friis

    1997-01-01

    This report deals with autogenous shrinkage of two concretes and the corresponding mortars. The theory of self-desiccation and autogenous deformation is presented. Autogenous shrinkage of mortar is measuredin a paste dilatometer at constant and varying temperatures. Similarly the autogenous shrin...

  2. Bulletin of Materials Science | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Based on the Arrhenius theory, the activation energy for densification of -Al2O3 at constant heating-rates sintering has been estimated. Sintering of -Al2O3 powder has been executed by the way of a push rod type dilatometer. It is shown that the apparent activation energy does not have a single value but depends ...

  3. Creep deformation of Co-Re-Ta-C alloys with varying C content-investigated in-situ by simultaneous synchrotron radiation diffraction

    Czech Academy of Sciences Publication Activity Database

    Karge, L.; Gilles, R.; Mukherji, D.; Stark, A.; Beran, Přemysl; Schell, N.; Hofmann, M.; Strunz, Pavel; Hausler, J.; Rösler, J.

    2018-01-01

    Roč. 719, č. 3 (2018), s. 124-131 ISSN 0921-5093 Institutional support: RVO:61389005 Keywords : high temperature creep * Co alloys * synchrotron diffraction * neutron diffraction * dilatometer Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 3.094, year: 2016

  4. Redox stability of SOFC: Thermal analysis of Ni-YSZ composites

    DEFF Research Database (Denmark)

    Pihlatie, Mikko; Kaiser, Andreas; Mogensen, Mogens Bjerg

    2009-01-01

    combinations of reduction and oxidation temperatures. Automated temperature and gas change programmes were implemented in thermogravimetry and identically repeated using a high precision dilatometer to show the dimensional behaviour of the cermets simultaneously with the Degree of Oxidation (DoO) as a function...

  5. Investigation of Dense Sand Properties in Shallow Depth using CPT and DMT

    DEFF Research Database (Denmark)

    Gaydadzhiew, Dimitar Todorov; Puscasu, Ionut; Vaitkunaite, Evelina

    2015-01-01

    ABSTRACT: The present paper is an investigation of the soil parameters of the given Aalborg University Sand No. 1 using the Flat Dilatometer Test (DMT) and the Cone Penetration Test (CPT). This clean sand type is considered to be similar to the sands found in the North Sea area. The research...

  6. Electric Field-Assisted Pressureless Sintering of Ceramic Protonic Conductors

    DEFF Research Database (Denmark)

    Muccillo, R.; Esposito, Vincenzo; de Florio, D. Z.

    2017-01-01

    Gadolinium, yttrium and samarium-doped barium cerate pressed pellets were submitted to flash sintering experiments isothermally in the temperature range 800-1300oC under 200 V cm-1 electric field. The pellets were positioned inside a dilatometer furnace with Pt-Ir electrodes connected either to a...

  7. High temperature thermophysical properties of (Th,U)O2 fuels

    International Nuclear Information System (INIS)

    Jarvis, T.; Banerjee, J.; Bhagat, R.K.; Ravi, K.; Sengupta, A.K.; Kutty, T.R.G.; Majumdar, S.

    2000-01-01

    In the present investigation thermal expansion data for sintered ThO 2 and ThO 2 containing 2,4,6,10 and 20% UO 2 pellets were measured using a high temperature dilatometer in the temperature range from ambient to 1773K in an inert atmosphere of argon

  8. High-resolution thermal expansion measurements under helium-gas pressure

    Science.gov (United States)

    Manna, Rudra Sekhar; Wolf, Bernd; de Souza, Mariano; Lang, Michael

    2012-08-01

    We report on the realization of a capacitive dilatometer, designed for high-resolution measurements of length changes of a material for temperatures 1.4 K ⩽ T ⩽ 300 K and hydrostatic pressure P ⩽ 250 MPa. Helium (4He) is used as a pressure-transmitting medium, ensuring hydrostatic-pressure conditions. Special emphasis has been given to guarantee, to a good approximation, constant-pressure conditions during temperature sweeps. The performance of the dilatometer is demonstrated by measurements of the coefficient of thermal expansion at pressures P ≃ 0.1 MPa (ambient pressure) and 104 MPa on a single crystal of azurite, Cu3(CO3)2(OH)2, a quasi-one-dimensional spin S = 1/2 Heisenberg antiferromagnet. The results indicate a strong effect of pressure on the magnetic interactions in this system.

  9. Thermodynamic properties of the solid solutions CuCr/sub 2/S/sub 4/ in Cu/sub 1///sub 2/M/sub 1///sub 2/Cr/sub 2/S/sub 4/ (M=Ga, In)

    Energy Technology Data Exchange (ETDEWEB)

    Titov, V.V.; Gordeev, I.V.; Kesler, Y.A.; Shchelkotunov, V.A.; Tret' yakov, Y.D.

    1985-09-01

    Using an adiabatic calorimeter and a quartz dilatometer, the temperature dependences of the heat capacity for the solid solutions CuCr/sub 2/S/sub 4/ in Cu/sub 1///sub 2/M/sub 1///sub 2/Cr/sub 2/S/sub 4/ (M - Ga, In) were determined, the different components of the heat capacity were evaluated, and the thermodynamic parameters of the magnetic transformation were calculated.

  10. Application of piezoceramic materials in low temperature scanning tunnel microscope

    International Nuclear Information System (INIS)

    Volodin, A.P.; Panich, A.E.

    1989-01-01

    Temperature dependences of the voltage-to-movement conversion coefficients for piezoceramic domestic materials PKR and TsTS-19 are measured using a capacitance dilatometer in the 0.4< T<300K temperature range. Anisotropy of thermal expansion of materials determined by the polarization vector is observed. Some recommendations concerning the use of the given materials in low-temperature scanning tunnel microscopes are given

  11. Untitled

    African Journals Online (AJOL)

    TiCl, Al(I-Bu), in toluene at 40°C. Rates of polymerization were fol- lowed hy dilatometric ... ing at 65°C at atmospheric pressure was col- lected and ... toluene. The total volume of the polymerisation mixture was kept to about lcm above the dilatometer bulb, stoppered and transferred to a thermost at set at the polymerisation ...

  12. Thermal Expansion and Magnetostriction Measurements at Cryogenic Temperature Using the Strain Gauge Method

    OpenAIRE

    Wei Wang; Wei Wang; Huiming Liu; Rongjin Huang; Rongjin Huang; Yuqiang Zhao; Chuangjun Huang; Shibin Guo; Yi Shan; Laifeng Li; Laifeng Li; Laifeng Li

    2018-01-01

    Thermal expansion and magnetostriction, the strain responses of a material to temperature and a magnetic field, especially properties at low temperature, are extremely useful to study electronic and phononic properties, phase transitions, quantum criticality, and other interesting phenomena in cryogenic engineering and materials science. However, traditional dilatometers cannot provide magnetic field and ultra-low temperature (<77 K) environment easily. This paper describes the design and ...

  13. Investigation of the relationships between mechanical properties and microstructure in a Fe-9%Cr ODS steel

    OpenAIRE

    Hary Benjamin; Guilbert Thomas; Wident Pierre; Baudin Thierry; Logé Roland; de Carlan Yann

    2016-01-01

    Ferritic-martensitic Oxide Dispersion Strengthened (ODS) steels are potential materials for fuel pin cladding in Sodium Fast Reactor (SFR) and their optimisation is essential for future industrial applications. In this paper, a feasibility study concerning the generation of tensile specimens using a quenching dilatometer is presented. The ODS steel investigated contains 9%Cr and exhibits a phase transformation between ferrite and austenite around 870 °C. The purpose was to generate different ...

  14. Sintering of hardmetals in different conditions: experimental results of 2-D dilatometry and computer simulations

    International Nuclear Information System (INIS)

    Gasik, M.; Zhang, B.; Kaskiala, M.; Yilkeraelae, J.

    2001-01-01

    Properties of WC-Co functionally gradated materials (FGM) manufactured by powder metallurgy from nanograin powders are studied. New optical system (a 2-D dilatometer) has been developed, using a high-resolution CCd camera and a dedicated software fro image processing. Sintering of WC-Co hard metals with different cobalt and grain growth inhibitors content was performed for various conditions (substrate, heating rate, temperature) and resulting anisotropy was measured. (author)

  15. Thermal expansion data of (Th,U)O2 fuels

    International Nuclear Information System (INIS)

    Sengupta, A.K.; Banerjee, J.; Bhagat, R.K.; Ramachandran, R.; Majumdar, S.; Purushotham, D.S.C.

    2000-04-01

    Thermal expansion data for sintered ThO 2 and ThO 2 containing 2, 4, 6, 10 and 20% UO 2 pellets were measured using a high temperature dilatometer in the temperature range from ambient to 1773 K. The dilatometer was first calibrated using a standard graphite sample as reference material. The reproducibility of the dilatometer was tested by measuring the coefficient of expansion of tungsten (NBS SRM 737) and comparing the data with that recommended by National Bureau of Standard. It was observed that there is close agreement between the experimental and reported data. The coefficient of expansion data of (Th,U)O 2 fuel indicate that out of all the six compositions, ThO 2 +2%UO 2 showed the maximum expansion of around 1.75% at 1773 K. However, the expansion data for all the compositions were very close to each other. Empirical equation correlating thermal expansion and temperature for all six compositions have been generated and reported. (author)

  16. Performance of MarSite Multi parameter Borehole Instrumentation

    Science.gov (United States)

    Guralp, Cansun; Tunc, Suleyman; Ozel, Oguz; Meral Ozel, Nurcan; Necmioglu, Ocal

    2017-04-01

    In this paper we present two year results obtained from the integrated multiparameter borehole system at Marsite. The very broad band (VBB) system have been operating since installation in November 2014; one year in a water filled borehole and one year in a dry Borehole. from January 2016. The real time data has been available to the community. The two Borehole environments are compared showing the superior performance of dry borehole environ- ment compared to water filled for a very broad band (VBB) seismometer. The practical considerations applied in both borehole installations are compared and the best borehole practical installation techniques are presented and discussed. The data is also compared with a surface 120 second broad band sensor and the seismic arrays with in MarSite region. The very long term performance, (one year data in a dry hole) of the VBB Borehole seismometer and the Dilatometer will be presented The high frequency performance of the VBB seismometer which extends to 150 Hz and the dilatometer are compared characterizing the results from the dilatometer.

  17. Determination of Sintered (Th,U)O2 Pellet at the Grain Growth Step

    International Nuclear Information System (INIS)

    Indrati-Y, Tundjung; Pristi-Hartati, Murdani; Ari-Handayani; Ginting, Aslina Br

    2000-01-01

    The determination of sintered (Th,U)O 2 pellet at the grain growth stephave been done by dilatometer and Scanning Electron Microscope (SEM). Thecalculation method based on the densification curve and quantitativemetallurgy. The green pellet be produced by single action compaction. Itspellet was heated on the dilatometer with heating rate 11 o C/minute and inthe argon atmosphere, 2 liters/hour. The activation energy at thedensification step can be calculated by densification curve only, but theactivation energy at the grain growth step can be calculated by densificationcurve or quantitative metallurgy. The capability of the dilatometer can beoperated until 1200 o C, so the densification curve based on the experiencecan be used to calculate activation energy at the densification step, 4.492kcal/mole. The activation energy at the grain growth step, which is 25.277kcal/mole, can be predicted by trial and error on n value. That activationenergy is almost the same with activation energy that based on thequantitative metallurgy method 25.042 kcal/mole. All of the activation energyfor the (Th,U)O 2 pellet sintering process is 29.769 kcal/mole. (author)

  18. Investigation of the relationships between mechanical properties and microstructure in a Fe-9%Cr ODS steel

    Directory of Open Access Journals (Sweden)

    Hary Benjamin

    2016-01-01

    Full Text Available Ferritic-martensitic Oxide Dispersion Strengthened (ODS steels are potential materials for fuel pin cladding in Sodium Fast Reactor (SFR and their optimisation is essential for future industrial applications. In this paper, a feasibility study concerning the generation of tensile specimens using a quenching dilatometer is presented. The ODS steel investigated contains 9%Cr and exhibits a phase transformation between ferrite and austenite around 870 °C. The purpose was to generate different microstructures and to evaluate their tensile properties. Specimens were machined from a cladding tube and underwent controlled heat treatments inside the dilatometer. The microstructures were observed using Electron Backscatter Diffraction (EBSD and tensile tests were performed at room temperature and at 650 °C. Results show that a tempered martensitic structure is the optimum state for tensile loading at room temperature. At 650 °C, the strengthening mechanisms that are involved differ and the microstructures exhibit more similar yield strengths. It also appeared that decarburisation during heat treatment in the dilatometer induces a decrease in the mechanical properties and heterogeneities in the dual-phase microstructure. This has been addressed by proposing a treatment with a much shorter time in the austenitic domain. Thereafter, the relaxation of macroscopic residual stresses inside the tube during the heat treatment was evaluated. They appear to decrease linearly with increasing temperature and the phase transformation has a limited effect on the relaxation.

  19. Transformation Stasis Phenomenon of Bainite Formation in Low-Carbon, Multicomponent Alloyed Steel

    Science.gov (United States)

    Lan, Liangyun; Kong, Xiangwei

    2017-11-01

    The transformation stasis phenomenon of bainite formation in low-carbon steel was detected using a high-resolution dilatometer. The phenomenon occurred at different stages for different isothermal temperatures. In combination with microstructural observation, the calculated overall activation energy of transformation and interface migration velocity shed new light on the cause of formation of the stasis phenomenon. The temporary stasis formed at the initial stage of phase transformation for high isothermal temperature was attributed to the drag effect of substitutional atoms, which leads to low-interface migration velocity and large overall activation energy.

  20. Physical and numerical modelling of heat treatment the precipitation-hardening complex-phase steel (CP

    Directory of Open Access Journals (Sweden)

    B. Koczurkiewicz

    2013-01-01

    Full Text Available The article presents the results of physical and numerical modeling of the processes of thermo- plastic treatment of an experimental complex-phase (CP steel. Numerical tests were carried out using a commercial software program, ThermoCalc. Based on the obtained test results, the austenitization temperature was established. Physical modeling was performed using a DIL 805A/D dilatometer and the Gleeble 3800 system. The characteristic temperatures of the steel and the primary austenite grain size were determined. The test pieces were also subjected to metallographic examinations and Vickers hardness tests. The obtained results served for building an actual CCT diagram for the steel tested.

  1. Absolute linear thermal-expansion measurements on copper and aluminum from 5 to 320 K

    International Nuclear Information System (INIS)

    Kroeger, F.R.; Swenson, C.A.

    1977-01-01

    A linear absolute dilatometer based on a three-terminal parallel-plate capacitor design has been used to obtain thermal expansion data for high-purity copper and aluminum from 5 to 320 K. These data have an absolute accuracy of +- 0.1% above 20 K for copper and above 30 K for aluminum, and agree well with published data at the higher temperatures. The disagreement which exists with other data below 5 K for copper and below 15 K for aluminum is believed to be sample dependent, but the mechanism is not known. The aluminum results in this region depend on the state of annealing of the sample

  2. ELASTO-PLASTIC DEFORMATION OF COMPOSITE POWDERS WITH LAYERED CARBON AND CARBIDE-FORMING ELEMENT COATING

    Directory of Open Access Journals (Sweden)

    V. N. Kovalevsky

    2012-01-01

    Full Text Available Coating structure formation under magnetron spraying of titanium and carbon cathodes and combined cathodes, namely cobalt (EP 131 – nickel, tungsten – carbon have been investigated under conditions of carbide separate synthesis within the temperature range of 650–1200 °C. Usage of cobalt and nickel particles as matrix material leads to their rapid thermal expansion under heating during sintering process in the dilatometer. Subsequent plastic deformation of sintered samples provides obtaining a composite powder material that is a composite with framing structure of cobalt, titanium and tungsten carbides in the coatings.

  3. Shape distortion and thermo-mechanical properties of SOFC components from green tape to sintering body

    DEFF Research Database (Denmark)

    Teocoli, Francesca; Ni, De Wei; Tadesse Molla, Tesfaye

    due to binder burn out, differential shrinkage behavior and to a potential interfacial reaction between the two materials. To analyze the phenomena, shrinkage of SOFC components single layers and bilayered samples were measured insitu by optical dilatometer. The densification mismatch stress, due...... to the strain rate difference between materials, was calculated using Cai’s model. Camber (curvature) development for in situ co-firing of a bi-layer ceramic green tape has been investigated. Analysis of shape evolution from green to sintered body can be carried out by the thermo-mechanical analysis techniques....

  4. Softening behaviour of brown coal ashes. Influence of ash components and gas atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Hegermann, R; Huettinger, K J [Karlsruhe Univ. (T.H.) (Germany, F.R.). Inst. fuer Chemische Technik

    1990-03-01

    The softening behaviour of brown coal ashes during gasification is important for three reasons: (1) Formation of large agglomerates, (2) inactivation of catalytically active ash components, (3) encapsulation of parts of the coal. The softening behaviour of the ashes was studied with a high temperature dilatometer at ambient pressure in various atmospheres (air, CO{sub 2}, Ar/H{sub 2}O, Ar, H{sub 2}/H{sub 2}O, H{sub 2}) using a push-rod with a conical tip. The heating rate was 5 Kmin{sup -1}, the final temperature 1000deg C, the residence time 1 h. (orig.).

  5. Thermal behaviors of liquid La-based bulk metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, D. W.; Wang, X. D., E-mail: wangxd@zju.edu.cn, E-mail: jiangjz@zju.edu.cn; Lou, H. B.; Cao, Q. P.; Jiang, J. Z., E-mail: wangxd@zju.edu.cn, E-mail: jiangjz@zju.edu.cn [International Center for New-Structured Materials (ICNSM), Laboratory of New-Structured Materials, State Key Laboratory of Silicon Materials, and Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Wang, L. W. [Institute of Materials Science and Engineering, Lanzhou University, Lanzhou 730000 (China); Zhang, D. X. [State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou 310027 (China)

    2014-12-14

    Thermal behaviors of liquid La-based bulk metallic glasses have been measured by using the dilatometer with a self-sealed sample cell. It is demonstrated that the strong glass forming liquid not only has the small thermal expansion coefficient but also shows the slow variation rate. Moreover, the strong glass former has relatively dense atomic packing and also small density change in the liquid state. The results suggest that the high glass forming ability of La-based metallic glasses would be closely related to the slow atomic rearrangements in liquid melts.

  6. Determination of near field excavation disturbance in crystalline rock

    International Nuclear Information System (INIS)

    Koopmans, R.; Hughes, R.W.

    1986-01-01

    The computerized dilatometer system has rapidly and economically provided deformation moduli of low and high modulus rock, determined the extent of excavation disturbance surrounding an underground opening and located open fracture within a rock mass. Results from both test sites indicate that the moduli obtained were influenced by the in situ tangential stress field. It has been shown that the near field excavation disturbance is kept to a minimum through the use of careful excavation techniques such as the tunnel boring machine. In turn, the in situ tangential stress levels and deformation moduli are maximized while the corresponding permeability is minimized

  7. Cause of Damage. Hot cracking; Schadensursache Heissrissigkeit

    Energy Technology Data Exchange (ETDEWEB)

    Wader, Therese [BENTELER Steel/Tube GmbH, Paderborn (Germany). Vorentwicklung Werkstoffe

    2016-10-15

    Under certain conditions, Nb-containing stainless steels are susceptible to hot cracking. Such conditions include low melting phases on the grain boundaries, a coarse-grained microstructure such as cast structures, microstructure orientations towards the main tensile direction and high processing temperatures. The case of damage was characterized using metallographic and microanalytical methods. In the laboratory, the critical temperature range for the formation of hot cracks could furthermore specifically be localized under mechanical stresses by means of a dilatometer aiming at clearly verifying the cause of the damage, namely ''hot cracks''.

  8. Low-temperature thermal expansion measurements in PrV2Al20

    International Nuclear Information System (INIS)

    Magata, A.; Matsumoto, Y.; Tsujimoto, M.; Tomita, T.; Sakai, A.; Nakatsuji, S.; Kiichler, R.

    2016-01-01

    We have measured thermal expansion of PrV 2 Al 20 and LaV 2 Al 20 from room temperature down to 2 K, using a capacitance dilatometer. Linear thermal expansion ΔL/L along [111] direction decreases monotonically on cooling in both materials. The extracted 4ƒ electrons contribution of the linear thermal expansion coefficient a clearly shows a broad peak at ∼ 30 K which may correspond to the crystal electric field excited state at 40 K suggested in the previous specific heat study. (paper)

  9. Linear thermal expansion coefficient of MgAl2O4(s)

    International Nuclear Information System (INIS)

    Dash, A.; Samui, P.; Naik, Y.P.; Chaudhary, Z.S.

    2011-01-01

    The coefficient of linear thermal expansion (α av ) of MgAl 2 O 4 (s) has been determined using a Netzsch 402 PC dilatometer with Al 2 O 3 (s) as the push-rod. The change in length per unit length was recorded as a function of temperature between room temperature to 1273 K at a heating rate of 8 K.min /1 , in argon flowing atmosphere. The average of three measurements was quoted as the α av for MgAl 2 O 4 (s). The linear thermal expansion was measured to an accuracy of ±3%. (author)

  10. A double-pass interferometer for measurement of dimensional changes

    International Nuclear Information System (INIS)

    Ren, Dongmei; Lawton, K M; Miller, J A

    2008-01-01

    A double-pass interferometer was developed for measuring dimensional changes of materials in a nanoscale absolute interferometric dilatometer. This interferometer realized the double-ended measurement of a sample using a single-detection double-pass interference system. The nearly balanced design, in which the measurement beam and the reference beam have equal optical path lengths except for the path difference caused by the sample itself, makes this interferometer have high stability, which is verified by the measurement of a quasi-zero-length sample. The preliminary experiments and uncertainty analysis show that this interferometer should be able to measure dimensional changes with characteristic uncertainty at the nanometer level

  11. Characterization of Ignalina NPP RBMK Reactors Graphite

    International Nuclear Information System (INIS)

    Hacker, P.J.; Neighbour, G.B.; Levinskas, R.; Milcius, D.

    2001-01-01

    The paper concentrates on the investigations of the initial physical properties of graphite used in production of graphite bricks of Ignalina NPP. These graphite bricks are used as nuclear moderator and major core structural components. Graphite bulk density is calculated by mensuration, pore volumes are measured by investigation of helium gas penetration in graphite pore network, the Young's modulus is determined using an ultrasonic time of flight method, the coefficient of thermal expansion is determined using a Netzsch dilatometer 402C, the fractured and machined graphite surfaces are studied using SEM, impurities are investigated qualitatively by EDAX, the degree of graphitization of the material is tested using X-ray diffraction. (author)

  12. Growth of polymer nanoparticles in microemulsion polymerization initiated with γ ray

    International Nuclear Information System (INIS)

    Xu Xiangling; Ge Xuewu; Ye Qiang; Zhang Zhicheng; Zuo Ju; Niu Aizhen; Zhang Manwei

    1999-01-01

    In microemulsion polymerization of styrene, butyl acrylate and methyl methacrylate initiated with gamma ray, growth of polymer nanoparticles was observed with photon correlation spectroscopy, and the conversion curve was recorded with a dilatometer. There is some similarity in the growth of polymer particles. The size of polymer particles rapidly increases up to their maximum at the early stage. With the increase of conversion, the large particles supply their monomer to newly formed particles and become smaller. In all these three microemulsion polymerizations, the evidence of continuous nucleation was observed. When monomer is styrene or butyl acrylate, a plateau of polymerization rate emerges. When monomer is methyl methacrylate, no plateau of polymerization is observed

  13. Uncertainty Evaluation of the Thermal Expansion of Gd2O3-ZrO2 with a System Calibration Factor

    International Nuclear Information System (INIS)

    Park, Chang Je; Kang, Kweon Ho; Na, Sang Ho; Song, Kee Chan

    2007-01-01

    Both gadolinia (Gd 2 O 3 ) and zirconia (ZrO 2 ) are widely used in the nuclear industry, including a burnable absorber and additives in the fabrication of a simulated fuel. Thermal expansions of a mixture of gadolinia (Gd 2 O 3 ) 20 mol% and zirconia (ZrO 2 ) 80 mol% were measured by using a dilatometer (DIL402C) from room temperature to 1500 .deg. C. Uncertainties in the measurement should be quantified based on statistics. Referring to the ISO (International Organization for Standardization) guide, the uncertainties of the thermal expansion were quantified for three parts - the initial length, the length variation, and the system calibration factor. The whole system, the dilatometer, is composed of many complex sub-systems and in fact it is difficult to consider all the uncertainties of the sub-systems. Thus, the system calibration factor was introduced with a standard material for the uncertainty evaluation. In this study, a new system calibration factor was formulated in a multiplicative way. Further, the effect of calibration factor with random deviation was investigated for the uncertainty evaluation of a thermal expansion

  14. Volume Recovery of Polymeric Glasses: Application of a Capacitance-based Measurement Technique

    Science.gov (United States)

    Sakib, Nazam; Simon, Sindee

    Glasses, including polymeric glasses, are inherently non-equilibrium materials. As a consequence, the volume and enthalpy of a glass evolve towards equilibrium in a process termed structural recovery. Several open questions and new controversies remain unanswered in the field. Specifically, the presence of intermediate plateaus during isothermal structural recovery has been reported in recent enthalpy work. In addition, the dependence of the relaxation time on state variables and thermal history is unclear. Dilatometry is particularly useful for structural recovery studies because volume is an absolute quantity and volumetric measurements can be done in-situ. A capillary dilatometer, fitted with a linear variable differential transducer, was used previously to measure volume recovery of polymeric glass formers in our laboratory. To improve on the limitations associated with that methodology, including competition between the range of measurements versus the sensitivity, a capacitance-based technique has been developed following the work of Richert, 2010. The modification is performed by converting the glass capillary dilatometer into a cylindrical capacitor. For precision in capacitance data acquisition, an Andeen-Hagerling ultra-precision capacitance bridge (2550A, 1 kHz) is used. The setup will be tested by performing the signatures of structural recovery as described by Kovacs, 1963. Experiments are also planned to address the open questions in the field.

  15. Analyzing the compressive behavior of porous Ti6Al4V by X-ray microtomography

    Energy Technology Data Exchange (ETDEWEB)

    Farias, Iván; Jimenez, Omar; Flores, Martín [Departamento de Ingeniería de Proyectos, Universidad de Guadalajara, Jalisco (Mexico); Olmos, Luís, E-mail: luisra24@gmail.com [Instituto de Investigaciones en Ciencias de la Tierra (INICIT), Universidad Michoacana de San Nicolás de Hidalgo, Michoacán (Mexico); Vergara-Hernández, Héctor Javier; Gárnica, Pedro [Instituto Tecnológico de Morelia, Michoacán (Mexico); Bouvard, Didier [Science et Ingénierie des Matériaux et Procédés (SIMaP), Université Grenoble Alpes (France)

    2017-11-15

    Samples with 40% vol. of pores and a pore size distribution between 100 and 500 μm were produced by powder metallurgy from Ti6Al4V alloy powders. Sintering was performed at 1300 °C during one hour in an inert Argon atmosphere in a vertical dilatometer. The compressive strength and the porosity of these samples was investigated before and after compression tests through X-ray microtomography. The values of the elastic modulus (8GPa) and yield strength (80MPa) are within the range of those used in bone implants. Porosity leads to greater deformation whereas fracture of compacts occurs perpendicularly to the applied load. It was determined that the origin of the failure is generated by rupture of interparticle necks and, large pores enhance the propagation of cracks. (author)

  16. LEMA facility and equipments for minor actinides compounds fabrication and characterisation

    Energy Technology Data Exchange (ETDEWEB)

    Donnet, L. [Commissariat a l' Energie Atomique - CEA, CEA/DEN/VRH/DTEC/SDTC/LEMA (France)

    2008-07-01

    The LEMA (Actinide based materials study laboratory) is mainly involved in minor actinides materials development and fabrication, from raw materials choice and synthesis to finished products including pin assembly. The aim of the technological analyses is to establish choices of raw materials and manufacturing techniques. The LEMA is located in the ATALANTE facility in Marcoule. It consists in two shielded chains (one specific for neutrons) and three hot laboratories. The laboratory has various apparatuses in hot cells such as: ball mills, press, dilatometer, TGA (thermo-gravimetry analyser), calcination and sintering furnaces (2000 deg. C). The laboratory has also characterisation apparatuses such as XRD and SEM (scanning electron microscopy) dedicated to structural and microstructural studies. Thanks to the diversity of its equipment, the LEMA has well established worldwide collaborations and takes part in international fuels/target fabrication and irradiation experiments. (author)

  17. Synthesis and characterization of nanostructured powders of hydroxyapatite and β-calcium phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Prants, W.T.; Muller, D.T.; Orzechowski, L.G.; Feit, G.; Delima, S.A.; Camargo, N.H.A.; Gemelli, E., E-mail: w_prants@hotmail.com, E-mail: danielt_muller@yahoo.com.br, E-mail: sarahamindelima@hotmail.com, E-mail: dem2nhac@joinville.udesc.br, E-mail: gemelli@joinville.udesc.br [Universidade do Estado de Santa Catarina (UDESC), Joinville, SC (Brazil). Campus Universitario Prof. Avelino Marcante

    2009-07-01

    Biphasic calcium phosphate (BCP) bioceramics are composed in a general manner from a mixture between hydroxyapatite (HA), and β-calcium phosphate. In the recent years, the BCP bioceramics are pointed out in researches from regeneration and reconstitution in osseous tissue, in reason of their similar mineralogical characteristics of the human bone structure, as great biodegradation, absorption and formation of precocious osseous tissue. The biphasic materials (BCP) are detached for use in medical and dental application, as filling bone cavities, maxillofacial treatment, medicaments discharge for treatment cancerous osteomyelitis and antibiotics discharge related with orthopedic injuries reparation. The aim of this work focused in synthesis and characterization of hydroxyapatite and β-calcium phosphate. The presented results are related with the mineralogical characterization with X-ray diffraction, thermal behavior with Differential Scanning Calorimetry and Dilatometer. The Scanning Electronic Microscopy (SEM) was used to help in the morphological characterization of the nanostructured powders. (author)

  18. Synthesis and characterization of nanostructured powders of hydroxyapatite and β-calcium phosphate

    International Nuclear Information System (INIS)

    Prants, W.T.; Muller, D.T.; Orzechowski, L.G.; Feit, G.; Delima, S.A.; Camargo, N.H.A.; Gemelli, E.

    2009-01-01

    Biphasic calcium phosphate (BCP) bioceramics are composed in a general manner from a mixture between hydroxyapatite (HA), and β-calcium phosphate. In the recent years, the BCP bioceramics are pointed out in researches from regeneration and reconstitution in osseous tissue, in reason of their similar mineralogical characteristics of the human bone structure, as great biodegradation, absorption and formation of precocious osseous tissue. The biphasic materials (BCP) are detached for use in medical and dental application, as filling bone cavities, maxillofacial treatment, medicaments discharge for treatment cancerous osteomyelitis and antibiotics discharge related with orthopedic injuries reparation. The aim of this work focused in synthesis and characterization of hydroxyapatite and β-calcium phosphate. The presented results are related with the mineralogical characterization with X-ray diffraction, thermal behavior with Differential Scanning Calorimetry and Dilatometer. The Scanning Electronic Microscopy (SEM) was used to help in the morphological characterization of the nanostructured powders. (author)

  19. The methodology of choice Cam-Clay model parameters for loess subsoil

    Science.gov (United States)

    Nepelski, Krzysztof; Błazik-Borowa, Ewa

    2018-01-01

    The paper deals with the calibration method of FEM subsoil model described by the constitutive Cam-Clay model. The four-storey residential building and solid substrate are modelled. Identification of the substrate is made using research drilling, CPT static tests, DMT Marchetti dilatometer, and laboratory tests. Latter are performed on the intact soil specimens which are taken from the wide planning trench at the depth of foundation. The real building settlements was measured as the vertical displacement of benchmarks. These measurements were carried out periodically during the erection of the building and its operation. Initially, the Cam Clay model parameters were determined on the basis of the laboratory tests, and later, they were corrected by taking into consideration numerical analyses results (whole building and its parts) and real building settlements.

  20. Effect of cooling rates on the weld heat affected zone coarse grain microstructure

    Directory of Open Access Journals (Sweden)

    Roman Celin

    2018-04-01

    Full Text Available The effect of a cooling rate on the S690Q quenched and tempered steel welded joint coarse grain heat affected zone microstructure was investigated using a dilatometer with controlled heating and cooling fixture. Steel samples were heated to a peak temperature of 1350 °C and cooled at the different cooling time Dt8/5. A dilatometric analysis and hardness measurements of the simulated thermal cycle coarse grain samples were done. Transformation start and finish temperature were determined using dilatation vs. temperature data analysis. The microstructure of the sample with a cooling time 5 s consists of martensite, whereas at cooling time 80 s a bainitic microstructure was observed. The investigated steel cooling cycle using simulation approach makes possible to determine the range of an optimum CG HAZ cooling time for the welding.

  1. Numerical cooling strategy design for hot rolled dual phase steel

    Energy Technology Data Exchange (ETDEWEB)

    Suwanpinij, Piyada; Prahl, Ulrich; Bleck, Wolfgang [RWTH Aachen (DE). Dept. of Ferrous Metallurgy (IEHK); Togobytska, Nataliya; Weiss, Wolf; Hoemberg, Dietmar [Weierstrass-Institut fuer Angewandte Analysis und Stochastik (WIAS) im Forschungsverbund Berlin e.V. (Germany)

    2010-10-21

    In this article, the Mo-Mn dual phase steel and its process parameters in hot rolling are discussed. The process window was derived by combining the experimental work in a hot deformation dilatometer and numerical calculation of process parameters using rate law models for ferrite and martensite transformation. The ferrite formation model is based on the Leblond and Devaux approach while martensite formation is based on the Koistinen- Marburger (K-M) formula. The carbon enrichment during ferrite formation is taken into account for the following martensite formation. After the completion of the parameter identification for the rate law model, the evolution of phases in multiphase steel can be addressed. Particularly, the simulations allow for predicting the preferable degree of retained strain and holding temperature on the run out table (ROT) for the required ferrite fraction. (orig.)

  2. Characterization and modelling techniques for gas metal arc welding of DP 600 sheet steels

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, K.; Prahl, U.; Bleck, W. [RWTH Aachen University, Department of Ferrous Metallurgy (IEHK) (Germany); Reisgen, U.; Schleser, M.; Abdurakhmanov, A. [RWTH Aachen University, Welding and Joining Institute (ISF) (Germany)

    2010-11-15

    The objectives of the present work are to characterize the Gas Metal Arc Welding process of DP 600 sheet steel and to summarize the modelling techniques. The time-temperature evolution during the welding cycle was measured experimentally and modelled with the softwaretool SimWeld. To model the phase transformations during the welding cycle dilatometer tests were done to quantify the parameters for phase field modelling by MICRESS {sup registered}. The important input parameters are interface mobility, nucleation density, etc. A contribution was made to include austenite to bainite transformation in MICRESS {sup registered}. This is useful to predict the microstructure in the fast cooling segments. The phase transformation model is capable to predict the microstructure along the heating and cooling cycles of welding. Tensile tests have shown the evidence of failure at the heat affected zone, which has the ferrite-tempered martensite microstructure. (orig.)

  3. The role of a chemical bond in thermal expansion of TlIn1-xYbxSe2 solid solutions

    International Nuclear Information System (INIS)

    Zarbaliev, M.M.; Sardarova, N.S.; Mamedov, E.G.; Nagiyev, A.B.

    2008-01-01

    Report focuses on the study of the role of the chemical bond in the thermal expansion of solid solutions TLIn 1 -x Yb x Se 2 (0dilatometer with induction registration. It is clear from the temperature dependence that, α(T) for all phases of studies is identical. This behavior α (T) is explained that, all investigated phases are crystallized, as parent compound TLInSe 2 , in the tetragonal system and type of chemical bonds between atoms in a crystal lattice one and the same. It leads to the same temperature changes of enharmonic part of the thermal variations of atoms in the crystal lattice. But the level of anharmonism depends on the character interatomic interaction and temperature, which defined the value of α

  4. A Negative Thermal Expansion Material of ZrMgMo3O12

    International Nuclear Information System (INIS)

    Song Wen-Bo; Liang Er-Jun; Liu Xian-Sheng; Li Zhi-Yuan; Yuan Bao-He; Wang Jun-Qiao

    2013-01-01

    A material with the formula ZrMgMo 3 O 12 having negative thermal expansion is presented and characterized. It is shown that ZrMgMo 3 O 12 crystallizes in an orthorhombic symmetry with space group Pnma(62) or Pna2 1 (33) and exhibits negative thermal expansion in a large temperature range (α l = −3.8 × 10 −6 K −1 from 300K to 1000K by x-ray diffraction and α l = −3.73 × 10 −6 K −1 from 295K to 775K by dilatometer). ZrMgMo 3 O 12 remains the orthorhombic structure without phase transition or decomposition at least from 123K to 1200K and is not hygroscopic. These properties make it an excellent material with negative thermal expansion for a variety of applications

  5. Negative thermal expansion up to 1000 C of ZrTiO4-Al2TiO5 ceramics for high-temperature applications

    International Nuclear Information System (INIS)

    Kim, I.J.; Kim, H.C.; Han, I.S.; Aneziris, C.G.

    2005-01-01

    High temperature structural ceramics based on Al 2 TiO 5 -ZrTiO 4 (ZAT) having excellent thermal-shock-resistance were synthesized by a reaction sintering. The ZAT ceramics sintered at 1600 C had a negative thermal expansions up to 1000 C and a much lower thermal expansion coefficient (0.3 ∝ 1.3 x 10 -6 /K) than that of polycrystalline Al 2 TiO 5 (1.5 x 10 -6 /K). These low thermal expansion are apparently due to a combination of microcracking caused by the large thermal expansion anisotropy of the crystal axes of the Al 2 TiO 5 phase. The microstructural degradation of the composites after various thermal treatment for high temperature applications were analyzed by scanning electron microscopy, X-ray diffraction, ultrasonic and dilatometer. (orig.)

  6. Comparing the dynamic and thermodynamic behaviors of Al{sub 86}Ni{sub 9}-La{sub 5}/(La{sub 0.5}Ce{sub 0.5}){sub 5} amorphous alloys

    Energy Technology Data Exchange (ETDEWEB)

    Li, G.H. [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Wang, W.M. [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China)], E-mail: weiminw@sdu.edu.cn; Bian, X.F.; Zhang, J.T.; Li, R.; Wang, L. [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China)

    2009-06-10

    The dynamic viscosities and thermodynamic dilatometric behaviors of Al{sub 86}Ni{sub 9}La{sub 5} and Al{sub 86}Ni{sub 9}(La{sub 0.5}Ce{sub 0.5}){sub 5} amorphous alloys were investigated using viscometer, differential scanning calorimetry (DSC) and conventional dilatometer. Comparing with Al{sub 86}Ni{sub 9}La{sub 5} alloy, Al{sub 86}Ni{sub 9}(La{sub 0.5}Ce{sub 0.5}){sub 5} alloy exhibits a larger viscosity and a larger average thermal expansion coefficient in the linear expansion zone ({alpha}{sub exp}). The viscosity and thermal expansion data suggest that the partial substitution La by Ce decreases the quantity of free volume in Al-Ni-La system by improving the continuous degree of atomic size, which leads to the improvement of glass forming ability.

  7. Thermal Expansion and Magnetostriction Measurements at Cryogenic Temperature Using the Strain Gauge Method.

    Science.gov (United States)

    Wang, Wei; Liu, Huiming; Huang, Rongjin; Zhao, Yuqiang; Huang, Chuangjun; Guo, Shibin; Shan, Yi; Li, Laifeng

    2018-01-01

    Thermal expansion and magnetostriction, the strain responses of a material to temperature and a magnetic field, especially properties at low temperature, are extremely useful to study electronic and phononic properties, phase transitions, quantum criticality, and other interesting phenomena in cryogenic engineering and materials science. However, traditional dilatometers cannot provide magnetic field and ultra-low temperature (thermal expansion and magnetostriction at cryogenic temperature using the strain gauge method based on a Physical Properties Measurements System (PPMS). The interfacing software and automation were developed using LabVIEW. The sample temperature range can be tuned continuously between 1.8 and 400 K. With this PPMS-aided measuring system, we can observe temperature and magnetic field dependence of the linear thermal expansion of different solid materials easily and accurately.

  8. Non-Fermi-Liquid Behavior in CeRu2Si2 at Ultralow Temperatures Studied by Thermal Expansion and Magnetostriction

    Science.gov (United States)

    Inoue, Daiki; Takama, Hiroyuki; Kaidou, Daisuke; Minegishi, Mitsuyuki; Ueno, Keisuke; Matsumoto, Koichi; Abe, Satoshi; Murayama, Shigeyuki

    2017-12-01

    We report the linear thermal expansion and magnetostriction of the heavy-fermion compound CeRu2Si2 along its a- and c-axes at temperatures down to 10 mK and in magnetic fields up to 9 T using a high-precision capacitive dilatometer. From the magnetostriction measurements, a large anisotropy between values for the coefficient of magnetostriction along the a- and c-axes was found in the Landau-Fermi-liquid (LFL) state. Non-Fermi-liquid (NFL) behavior was observed for both the linear thermal expansion below 60 mK for all applied magnetic fields and the linear magnetostriction below 0.5 T and 300 mK. The results suggest the existence of an additional pressure-driven quantum critical point (QCP), and a crossover from the NFL state to the LFL state occurs in CeRu2Si2 at ambient pressure near the QCP.

  9. Thermal expansion studies on Inconel-600[reg] by high temperature X-ray diffraction

    International Nuclear Information System (INIS)

    Raju, S.; Sivasubramanian, K.; Divakar, R.; Panneerselvam, G.; Banerjee, A.; Mohandas, E.; Antony, M.P.

    2004-01-01

    The lattice thermal expansion characteristics of Inconel-600[reg] have been studied by high temperature X-ray diffraction (HT-XRD) technique in the temperature range 298-1200 K. Altogether four experimental runs were conducted on thin foils of about 75-100 μm thickness. The diffraction profiles have been accurately calibrated to offset the shift in 2θ values introduced by sample buckling at elevated temperatures. The corrected lattice parameter data have been used to estimate the instantaneous and mean linear thermal expansion coefficients as a function of temperature. The thermal expansion values estimated in the present study show a fair degree of agreement with other existing dilatometer based bulk thermal expansion estimates. The lattice parameter for this alloy at 300 K is found to be 0.3549(1) nm. The mean linear thermal expansivity is found to be 11.4 x 10 -6 K -1

  10. Thermal Expansion of Ni3Al Intermetallic Compound: Experiment and Simulation

    International Nuclear Information System (INIS)

    Wang Hai-Peng; Lü Peng; Zhou Kai; Wei Bing-Bo

    2016-01-01

    The thermal expansion of Ni 3 Al intermetallic compound is determined by a thermal dilatometer and simulated by the molecular dynamics method. The results of the linear thermal expansion coefficients are presented from 200 K up to the maximum temperature of 1600 K. The single phase of Ni 3 Al intermetallic compound is confirmed by x-ray diffraction together with DSC melting and solidification peaks, from which the solidus and the liquidus temperatures are obtained to be 1660 and 1695 K, respectively. The measured linear thermal expansion coefficient increases from 1.5 × 10 −5 to 2.7 × 10 −5 K −1 in the experimental temperature range, in good agreement with the data obtained by the molecular dynamics simulation, just a slight difference from the temperature dependence coefficient. Furthermore, the atomic structure and position are presented to reveal the atom distribution change during thermal expansion of Ni 3 Al compound. (paper)

  11. Thermal Expansion and Magnetostriction Measurements at Cryogenic Temperature Using the Strain Gauge Method

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2018-03-01

    Full Text Available Thermal expansion and magnetostriction, the strain responses of a material to temperature and a magnetic field, especially properties at low temperature, are extremely useful to study electronic and phononic properties, phase transitions, quantum criticality, and other interesting phenomena in cryogenic engineering and materials science. However, traditional dilatometers cannot provide magnetic field and ultra-low temperature (<77 K environment easily. This paper describes the design and test results of thermal expansion and magnetostriction at cryogenic temperature using the strain gauge method based on a Physical Properties Measurements System (PPMS. The interfacing software and automation were developed using LabVIEW. The sample temperature range can be tuned continuously between 1.8 and 400 K. With this PPMS-aided measuring system, we can observe temperature and magnetic field dependence of the linear thermal expansion of different solid materials easily and accurately.

  12. Thermal simulation of drift emplacement (TSS): In-situ instrumentation and numerical modeling of stress measurement methods

    International Nuclear Information System (INIS)

    Heusermann, S.

    1988-01-01

    In the course of the planned demonstration test Thermal Simulation of Drift Emplacement (TSS) BGR is carrying out in-situ-measurements of rock stresses, rock deformability and permeability of salt rock and backfill material. The following techniques developed and proved by BGR during the last years are planned to be used in the TSS project: overcoring technique, dilatometer technique, hard inclusion technique, slot-cutting techniques, large-flatjack technique, compensation tests in laboratory, vacuum tests, injection tests, and tracer tests. The purpose of measurements is to determine: the initial stress state; stress gradients around test drifts; stress change caused by mining activities, by creep and stress relaxation and by temperature; the in-situ load-deformation behavior of rock salt; the permeability of rock salt around test drifts; the compaction behavior of backfill material; and the load-deformation behavior of rock salt and borehole grout in laboratory tests

  13. Determination of irradiation temperature using SiC temperature monitors

    International Nuclear Information System (INIS)

    Maruyama, Tadashi; Onose, Shoji

    1999-01-01

    This paper describes a method for detecting the change in length of SiC temperature monitors and a discussion is made on the relationship between irradiation temperature and the recovery in length of SiC temperature monitors. The SiC specimens were irradiated in the experimental fast reactor JOYO' at the irradiation temperatures around 417 to 645degC (design temperature). The change in length of irradiated specimens was detected using a dilatometer with SiO 2 glass push rod in an infrared image furnace. The temperature at which recovery in macroscopic length begins was obtained from the annealing intersection temperature. The results of measurements indicated that a difference between annealing intersection temperature and the design temperature sometimes reached well over ±100degC. A calibration method to obtain accurate irradiation temperature was presented and compared with the design temperature. (author)

  14. Effects of atmosphere in sintering pure or doped PZT with barium and strontium ions; Efeito da atmosfera na sinterizacao do PZT puro ou dopado com ions bario e estroncio

    Energy Technology Data Exchange (ETDEWEB)

    Simoes, A.Z.; D`Alkimin, R.; Zaghete, M.A.; Perazolli, L.; Varela, J.A.; Gimenes, E.R. [UNESP, Araraquara, SP (Brazil). Inst. de Quimica

    1996-05-01

    Lead zirconate titanate powder with Zr/Ti ratio of 50/50 was prepared by Pechini method and doped with 1,0; 3,0 and 5,0 mol% of Ba or Sr ions. The powder was calcined at 700 deg C by 3 hours and milled by 6 hours in isopropyl alcohol. Surface area was measured by BET method and the purity of the powder characterized by IV. DRX was used to characterize the crystal structure. The powder was isostatically pressed at 230 MPa and sintered in a dilatometer furnace with constant heating rate of 10 deg C/min up to 1100 deg C. Argon, synthetic air oxygen and oxygen with water vapor were used at atmosphere. The presence of Ba or Sr ions reduce the temperature of maximum sintering rate for all considered atmospheres. The effects of each sintering atmosphere of doped PZT is discussed. (author) 6 refs., 3 figs., 2 tabs.

  15. Determination of brazed joint constitutive law by inverse method

    International Nuclear Information System (INIS)

    Lovato, G.; Moret, F.; Gallo, P. le; Cailletaud, G.; Pilvin, P.

    1993-01-01

    An important parameter often neglected for the calculation of residual stresses in brazed ceramic/metal assemblies is the joint constitutive law. In situ camber measurements on a model system (axisymmetric TZM/InCuSil ABA/316L samples) performed using a special vertical dilatometer during the whole brazing thermal cycle are compared with results of FEM calculations based on published filler metal constitutive laws. A strong disagreement is observed. Actual constitutive law of the joint is determined from these measurements using a numerical inverse method. Calculated displacements are fully consistent with experimental ones. True solidification temperature of the joint is determined. The identified constitutive law of the joint exhibits a low flow stress from solidification temperature to 320 C. (orig.)

  16. Hot deformation effect on the kinetics of austenite transformation under continuous cooling conditions

    International Nuclear Information System (INIS)

    Bernshtejn, M.L.; Zajmovskij, V.A.; Kisteh, N.V.; Samedov, O.V.; Faldin, S.A.

    1979-01-01

    The effect of hot deformation on the kinetics of austenite transformations in the commercial 4040Kh 40KhN, and 40KhNMA steels on continuous cooling was studied. The transformations were studied using a dilatometer of a special design which permits a specimen to be fixed quickly in holders after hot deformation. It is stated that in hot-deformed austenite the pearlite transformation proceeds at higher temperatures and in a narrower temperature range. Austenite deformation provides an opportunity to obtain a more fine ferrite-pearlite structure and ensures a uniform distribution of a structurally free ferrite in the steel bulk. The effect of hot deformation on the structure of ferrite decomposition products in the 40KhN and 40KhNMA steels is more complicated, which is connected with a substantial change in the kinetics of pearlite and intermediate transformations

  17. Analysis of heat transfer in plain carbon steels

    International Nuclear Information System (INIS)

    Han, Heung Nam; Lee, Kyung Jong

    1999-01-01

    During cooling of steels, the heat transfer was controlled by radiation, convection, conduction and heat evolution from phase transformation. To analyze the heat transfer during cooling precisely, the material constants such as density, heat capacity and the heat evolved during transformation were obtained as functions of temperature and chemical composition for each phase observed in plain carbon steel using a thermodynamic analysis based on the sublattice model of Fe-C-Mn system. The results were applied to 0.049 wt% and 0.155 wt% carbon steels with an austenitic stainless steel as reference by developing a proper heat transfer governing equation. The equation was solved using the lumped system method. In addition, using a transformation dilatometer with adequate experimental conditions to clarify the individual heat transfer effect, the transformation heat evolved during cooling and the transformation behavior as well as the temperature change were observed. The predicted temperature profiles during cooling were well agreed with the measured ones

  18. Borehole Volumetric Strainmeter Calibration From a Nearby Seismic Broadband Array at Etna Volcano

    Science.gov (United States)

    Currenti, G.; Zuccarello, L.; Bonaccorso, A.; Sicali, A.

    2017-10-01

    Strainmeter and broadband seismic signals have been analyzed jointly with the aim of calibrating a borehole strainmeter at Etna volcano by using a seismo-geodetic technique. Our results reveal a good coherence between the dynamic strains estimated from seismometer data and strains recorded by a dilatometer in a low-frequency range [0.03-0.06 Hz] at the arrival of teleseismic waves. This significant coherence enabled estimating the calibration coefficient and making a comparison with calibration results derived from other methods. In particular, we verified that the proposed approach provides a calibration coefficient that matches the results obtained from the comparison of the recorded strain both with theoretical strain tides and with normal-mode synthetic straingrams. The approach presented here has the advantage of exploiting recorded seismic data, avoiding the use of computed strain from theoretical models.

  19. Sintering study and properties of alumina matrix composites reinforced with NbC, TiC and TaC

    International Nuclear Information System (INIS)

    Tonello, K.P.S.; Trombini, V.; Bressiani, A.H.A.; Bressiani, J.C.

    2011-01-01

    Al_2O_3 based composite materials are very promising due to their good mechanical properties, and have been studied as an alternative for the production of materials with high wear resistance. In alumina based composites the addition of carbides can change and improve the sintering and mechanical properties of materials. The objective was to study the effect of adding small concentrations of NbC, TaC and TiC in the sintering, microstructure and mechanical properties of alumina composites. The sintering study was conducted in dilatometer, with heating rate of 20 ° C / min. up to 1800 ° C, and the study of microstructure and properties of the composites was performed in hot pressed samples, sintered at 1500°C/30min with constant pressure of 20MPa. The results indicated that the addition of carbides modified the sintering behavior and also indicated that the hardness and fracture toughness were improved by the presence of carbide particles. (author)

  20. Intrinsic thermal expansion of crystal defects

    International Nuclear Information System (INIS)

    Ganne, J.-P.

    1981-02-01

    Although the phenomenon of thermal expansion has long been known, the intrinsic thermal expansion coefficient (ITEC) βsub(d) of a point defect, derived from its formation volume vsub(d), has never been measured directly. The differential dilatometer by interferometry built by ASTY and GILDER is described. It has allowed βsub(d) to be measured for several defects. Vacancies and small interstitial loops were produced in aluminium by low temperature (20 K) fast neutron irradiation followed by an anneal up to the beginning of stage III (160 K). The very high value of the measured ratio βsub(d)/β 0 (12+-4) is comparable with a lattice statics calculated (42) value (11.5 0 [fr

  1. LEMA facility and equipments for minor actinides compounds fabrication and characterisation

    International Nuclear Information System (INIS)

    Donnet, L.

    2008-01-01

    The LEMA (Actinide based materials study laboratory) is mainly involved in minor actinides materials development and fabrication, from raw materials choice and synthesis to finished products including pin assembly. The aim of the technological analyses is to establish choices of raw materials and manufacturing techniques. The LEMA is located in the ATALANTE facility in Marcoule. It consists in two shielded chains (one specific for neutrons) and three hot laboratories. The laboratory has various apparatuses in hot cells such as: ball mills, press, dilatometer, TGA (thermo-gravimetry analyser), calcination and sintering furnaces (2000 deg. C). The laboratory has also characterisation apparatuses such as XRD and SEM (scanning electron microscopy) dedicated to structural and microstructural studies. Thanks to the diversity of its equipment, the LEMA has well established worldwide collaborations and takes part in international fuels/target fabrication and irradiation experiments. (author)

  2. Thermal expansion and magnetostriction measurements at cryogenic temperature using the strain gage method

    Science.gov (United States)

    Wang, Wei; Liu, Huiming; Huang, Rongjin; Zhao, Yuqiang; Huang, Chuangjun; Guo, Shibin; Shan, Yi; Li, Laifeng

    2018-03-01

    Thermal expansion and magnetostriction, the strain responses of a material to temperature and a magnetic field, especially properties at low temperature, are extremely useful to study electronic and phononic properties, phase transitions, quantum criticality, and other interesting phenomena in cryogenic engineering and materials science. However, traditional dilatometers cannot provide magnetic field and ultra low temperature (<77 K) environment easily. This paper describes the design and test results of thermal expansion and magnetostriction at cryogenic temperature using the strain gage method based on a Physical Properties Measurements System (PPMS). The interfacing software and automation were developed using LabVIEW. The sample temperature range can be tuned continuously between 1.8 K and 400 K. With this PPMS-aided measuring system, we can observe temperature and magnetic field dependence of the linear thermal expansion of different solid materials easily and accurately.

  3. Analyzing the compressive behavior of porous Ti6Al4V by X-ray microtomography

    International Nuclear Information System (INIS)

    Farias, Iván; Jimenez, Omar; Flores, Martín; Olmos, Luís; Vergara-Hernández, Héctor Javier; Gárnica, Pedro; Bouvard, Didier

    2017-01-01

    Samples with 40% vol. of pores and a pore size distribution between 100 and 500 μm were produced by powder metallurgy from Ti6Al4V alloy powders. Sintering was performed at 1300 °C during one hour in an inert Argon atmosphere in a vertical dilatometer. The compressive strength and the porosity of these samples was investigated before and after compression tests through X-ray microtomography. The values of the elastic modulus (8GPa) and yield strength (80MPa) are within the range of those used in bone implants. Porosity leads to greater deformation whereas fracture of compacts occurs perpendicularly to the applied load. It was determined that the origin of the failure is generated by rupture of interparticle necks and, large pores enhance the propagation of cracks. (author)

  4. Densification behaviour of UO2 in six different atmospheres

    International Nuclear Information System (INIS)

    Kutty, T.R.G.; Hegde, P.V.; Khan, K.B.; Basak, U.; Pillai, S.N.; Sengupta, A.K.; Jain, G.C.; Majumdar, S.; Kamath, H.S.; Purushotham, D.S.C.

    2002-01-01

    The shrinkage behaviour of UO 2 has been studied using a dilatometer in various atmospheres of Ar, Ar-8%H 2 , vacuum, CO 2 , commercial N 2 and N 2 +1000 ppm of O 2 . The onset of shrinkage occurs at around 300-400 deg. C lower in oxidizing atmospheres such as CO 2 , commercial N 2 and N 2 +1000 ppm O 2 compared to that in reducing or inert atmospheres. Shrinkage behaviour of UO 2 is almost identical in Ar, Ar-8%H 2 and vacuum. The shrinkage in N 2 +1000 ppm O 2 begins at a lower temperature than that in the commercial N 2 . The mechanism of sintering in the reducing, inert and vacuum atmospheres is explained by diffusion of uranium vacancies and that in the oxidizing atmospheres by cluster formation

  5. Kinetics and Mechanism of the Polymerization of Methyl Methacrylate in a Y(acac)3/n-BuMgCl System

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Based on the kinetics equation proposed by T. Kagiya, the kinetic study on the polymerization of methyl methacrylate(MMA) by Y(acac)3/n-BuMgCl was carried out with a dilatometer. It was found that the rate of propagation is the first order with respect to the concentration of both active center and monomer. Thus, the equation of propagation rate can be described as Rp=Kp[c*][M]. In addition, the instantaneous chain initiation and single molecular termination were concluded for the present system. The activation energy is close to 32 kJ/mol. In the polymerization, n-BuMgCl acts not only as the cocatalyst, but also as chain transfer agent with cI=3.6×10-4.

  6. Structure and properties of TeO2-WO3 system glasses

    International Nuclear Information System (INIS)

    Kolobkov, V.P.; Ovcharenko, N.V.; Morozova, I.N.; Chebotarev, S.A.; Chikovskij, A.N.; Arkatova, T.G.

    1987-01-01

    Study of TeO 2 -WO 3 system is of interest for production of high-refractive-glasses with comparatively low crystallizability. Results of investigating some properties and structural features of this system glasses are presented. Composition and properties of studied glasses are presented. The properties were studied using the following techniques: the density was measured by hydrostatic weighing in toluene; thermal expansion coefficient was measured in quartz dilatometer DKV-5A; dilatometric temperature of glass softening (T g ) was defined as an intersection point of linear and curved parts of the plot of thermal expansion coefficient; refractive index (RI) - by immersion method; dielectric properties are measured. Consideration of vibronic spectra permits to conclude that in tungsten-tellurium glasses rare earth activator ions are arranged near tellurite and tungstate groupings proportional to glass-forming component content

  7. Investigation on grain refinement and precipitation strengthening applied in high speed wire rod containing vanadium

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Da-yong; Xiao, Fu-ren, E-mail: frxiao@ysu.edu.cn; Wang, Bin; Liu, Jia-ling; Liao, Bo, E-mail: cyddjyjs@263.net

    2014-01-13

    To obtain necessary information for the simulation of high speed wire production process, the effect of grain refinement and precipitation strengthening on two high speed wire rod steels with different vanadium and nitrogen contents was investigated by continuous cooling transformation (CCT) characteristics. CCT curves were constructed by the dilatometer test and microscopic observation. Results showed that the formation of intra-granular ferrite (IGF) could refine grain remarkably and accelerate the ferrite transformation. Schedules for high speed wire production process focused on the effect of cooling rate. Ferrite grain was refined by increasing cooling rate and the formation of IGF. The microhardness calculation revealed that the steels were strengthened mostly by a combined effect of grain refinement and precipitation hardening. Degenerated pearlite was observed at lower transformation temperature and the fracture morphology changed from cementite lamellar to nanoscale cementite particle with increasing cooling rate. Based on the analysis above, an optimal schedule was applied and the microstructure and microhardness were improved.

  8. Linear thermal expansion of SrTiO3

    International Nuclear Information System (INIS)

    Tsunekawa, S.; Watanabe, H.F.J.; Takei, H.

    1984-01-01

    The linear thermal expansion of SrTiO 3 in the temperature range 10 to 150 K is measured with a relative accuracy of 5 x 10 -7 by using a three-terminal capacitance dilatometer. The dilation ΔL/L of a single-domain crystal is converted to the ratio of the pseudo-cubic cell constants a(T)/a(T/sub a/) by the equation a(T)/a(T/sub a/) = [1 + (ΔL/L)/sub T/]/[1 + (ΔL/L)/sub T//sub a/], where L is the specimen length, T/sub a/ is the cubic-to-tetragonal transition temperature and T 6 octahedra around the [001] axis. The temperature at which the dilation shows a minimum, 37.5 K, is very close to the transition point T/sub c/ = (32 +- 5) K predicted by Cowley. (author)

  9. Linear thermal expansion measurements on silicon from 6 to 340 K

    International Nuclear Information System (INIS)

    Lyon, K.G.; Salinger, G.L.; Swenson, C.A.; White, G.K.

    1977-01-01

    Linear thermal expansion measurements have been carried out from 6 to 340 K on a high-purity silicon sample using a linear absolute capacitance dilatometer. The accuracy of the measurements varies from +- 0.01 x 10 -8 K -1 at the lowest temperatures to +- 0.1 x 10 -8 K -1 or 0.1%, whichever is greater, near room temperature, and is sufficient to establish silicon as a thermal expansion standard for these temperatures. The agreement with previous data is satisfactory at low temperatures and excellent above room temperature where laser-interferometry data of comparable accuracy exist. Thermal expansions calculated from ultrasonic and heat-capacity data are preferred below 13 K where experimental problems occurred

  10. 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

  11. Microstructure evolution of ASTM 335 P91 steel, subjected to continuous cooling

    International Nuclear Information System (INIS)

    Carrizo, D.A; Danon, C.A; Ramos, C.P

    2012-01-01

    This paper studies the influence of the cooling rate on an isothermal phase transformations in ASTM A335 P91 steel, by the analysis of the resulting microstructure after several continuous cooling cycles under fixed austenization conditions. The CCT (Continuous Cooling Transformation) diagram of this material has already been reported in the literature, so the main phase fields are known, and they depend on the austenitic grain size and the cooling rate. Five samples were tested in a dilatometer, they were austenized and then cooled at different rates between 50 o C/h and 300 o C/h. The identification and characterization of the resulting phases was carried out by using Scanning Electron Microscopy, X-ray Diffraction and Mossbauer Spectroscopy. The obtained results allowed to add information about the presence of retained austenite and (Fe,Cr) 3 C - type carbides to the CCT diagram of the material (author)

  12. Seismicity Controlled by a Frictional Afterslip During a Small-Magnitude Seismic Sequence (ML Taiwan

    Science.gov (United States)

    Canitano, Alexandre; Godano, Maxime; Hsu, Ya-Ju; Lee, Hsin-Ming; Linde, Alan T.; Sacks, Selwyn

    2018-02-01

    We report evidence for frictional afterslip at shallow depths (about 5 to 7 km) during a small-magnitude seismic sequence (with MLTaiwan. The afterslip, which was recorded by a nearby borehole dilatometer, lasted about a month with a cumulative geodetic moment magnitude of 4.8 ± 0.2. The afterslip comprised two stages and controlled the aftershock sequence. The first postseismic stage, which followed a ML 4.6 earthquake, lasted about 6 h and mostly controlled the ruptures of neighboring asperities (e.g., multiplets) near the hypocenter. Then, a 4 week duration large afterslip event following a ML 4.9 earthquake controlled the rate of aftershocks during its first 2 days through brittle creep. The study presents a rare case of simultaneous seismological and geodetic observations for afterslip following earthquakes with magnitude lower than 5. Furthermore, the geodetic moment of the postseismic phase is at least equivalent to the coseismic moment of the sequence.

  13. Fundamentals of liquid phase for modern cermets and functionally graded cemented carbonitrides (FGCC)

    International Nuclear Information System (INIS)

    Chen, L.; Lengauer, W.; Ettmayer, P.; Dreyer, K.; Daub, H.W.; Kassel, D.

    2001-01-01

    Metallurgical reactions and microstructure developments during sintering of modern cermets and functionally graded cemented carbonitrides (FGCC) were investigated by modern thermal and analytical methods such as mass spectrometer (MS), differential thermal analysis (DTA), differential scanning calorimeter (DSC), dilatometer (DIL), microscopy and analytical electronic microscopy with energy dispersive spectrometer (EDS). The complex phase reactions and phase equilibrium in the multi-component system Ti/Mo/W/Ta/Nb/C,N-Co/Ni were studied. The melting behaviors in the systems of TiC-WC/MoC-Ni/Co, TiC-TiN-WC-Co and TiCN-TaC-WC-Co have been established. By better understanding of the mechanisms that govern the sintering processing and metallurgical reactions, new cermets and different types of functionally graded cemented carbonitrides (FGCC) with desired microstructures and properties were developed and fabricated. (author)

  14. The Microstructure and Properties of Super Martensitic Stainless Steel Microalloyed with Tungsten and Copper

    Science.gov (United States)

    Ye, Dong; Li, Jun; Liu, Yu-Rong; Yong, Qi-Long; Su, Jie; Cao, Jian-Chun; Tao, Jing-Mei; Zhao, Kun-Yu

    2011-06-01

    The microstructure and properties of super martensitic stainless steel (SMSS) microalloyed with tungsten and copper were studied by means of optical microscopy, dilatometer, X-ray diffraction, and tensile tests. The results showed that the microstructure of SMSS, after quenching and tempering, was a typical biphase structure with tempered martensite and reversed austenite dispersedly distributed in the martensite matrix. W and Cu were added into the SMSS to reduce the transformation temperature (Ms) and improve the strength and hardness of the matrix by grain refining and solid solution strengthening. Thermocalc calculations confirmed that M23C6 compound and Laves phase were precipitated during tempering in the investigated steel. Compared with the traditional SMSS, the steel microalloyed with W and Cu performed better mechanical properties.

  15. Study by dispersed light photometry of the polymerization of methacrylates by gamma radiation

    International Nuclear Information System (INIS)

    Isaurralde, Haidee; Molinari, M.A.

    1976-04-01

    Determinations of molecular weights of methyl methacrylate irradiated in presence and in absence of oxygen were made at different exposure times exponential function of the time of irradiation. The molecular weight of polymethyl metacrilate obtained by irradiating the monomer in presence of nitrogen or oxygen was determined, and the value 4,4 x 10 6 was obtained in both cases, for total polymerization. Different experiments were made to determine the yield of polimerization, by precipitation and recuperation of the precipitate, and with dilatometer, and we saw that in presence of nitrogen the yield is much larger than in presence of oxygen, being in the first case 100% at 4 hs. 45 min., and in the second 4% for the same exposure time. (author) [es

  16. Dilatometric examination of moulds with plaster binder

    Directory of Open Access Journals (Sweden)

    M. Nadolski

    2011-01-01

    Full Text Available Investigations concerning thermal expansion of moulding materials with plaster binder have been performed for two mixture compositionsof Authors’ own design, as well as for the material used in jewellery industry under the Prima-Cast trade name, and for ThermoMold 1200moulding material. The results of dilatometric examinations of these materials, carried out within the temperature range from about 20°Cto 650°C by means of the DA-3 automatic dilatometer, have been compared. An analysis of this comparison has revealed that it is thematrix composition which is decisive for the magnitude of dimensional changes of moulds, and that applying components which do notexhibit polymorphic transformations reduces dimensional changes of a mould during its thermal treatment.

  17. Dilatometric studies on uranium-zirconium-fissium alloy

    International Nuclear Information System (INIS)

    Banerjee, Aparna; Kulkarni, S.G.; Kulkarni, R.V.; Kaity, Santu

    2012-01-01

    The knowledge of thermophysical properties of U-Zr alloys are important for modelling fuel behaviour in nuclear reactor. Fissium is an alloy that approximates the equilibrium concentration of the metallic fission product elements left by metallurgical reprocessing. Coefficient of thermal expansion (CTE) data is needed to calculate stresses occurring in fuel and cladding with change in temperature. Coefficient of thermal expansion can be utilized to determine the change of alloy density as a function of temperature. In the present investigation, thermophysical properties like coefficient of thermal expansion and density were determined using dilatometer for U-20wt.%Zr-5wt.%Fs alloy prepared by arc melting process. The microstructural investigation was carried out using scanning electron microscope

  18. On the use of volumetric strain meters to infer additional characteristics of short-period seismic radiation

    Science.gov (United States)

    Borcherdt, R.D.; Johnston, M.J.S.; Glassmoyer, G.

    1989-01-01

    Volumetric strain meters (Sacks-Evertson design) are installed at 15 sites along the San Andreas fault system, to monitor long-term strain changes for earthquake prediction. Deployment of portable broadband, high-resolution digital recorders (GEOS) at several of the sites extends the detection band for volumetric strain to periods shorter than 5 ?? 10-2 sec and permits the simultaneous observation of seismic radiation fields using conventional short-period pendulum seismometers. Recordings of local and regional earthquakes indicate that dilatometers respond to P energy but not direct shear energy and that straingrams can be used to resolve superimposed reflect P and S waves for inference of wave characteristics not permitted by either sensor alone. Simultaneous measurements of incident P- and S-wave amplitudes are used to introduce a technique for single-station estimates of wave field inhomogeneity, free-surface reflection coefficients and local material P velocity. -from Authors

  19. Rock stress investigations

    International Nuclear Information System (INIS)

    Pahl, A.; Heusermann, St.; Braeuer, V.; Gloeggler, W.

    1989-04-01

    On the research project 'Rock Stress Mesurements' the BGR has developed and tested several methods for use in boreholes at a depth of 200 m. Indirect stress measurements using overcoring methods with BGR-probes and CSIR-triaxial cells as well as direct stress measurements using the hydraulic-fracturing method were made. To determine in-situ rock deformation behavior borehole deformation tests, using a BGR-dilatometer, were performed. Two types of the BGR-probe were applied: a four-component-probe to determine horizontal stresses and a five-component-probe to determine a quasi three-dimensional stress field. The first time a computer for data processing was installed in the borehole together with the BGR-probe. Laboratory tests on low cylinders were made to study the stress-deformation behavior. To validate and to interprete the measurement results some test methods were modelled using the finite-element method. The dilatometer-tests yielded high values of Young's modulus, whereas laboratory tests showed lower values with a distinct deformation anisotropy. Stress measurements with the BGR-probe yielded horizontal stresses being higher than the theoretical overburden pressure. These results are comparable to the results of the hydraulic fracturing tests, whereas stresses obtained with CSIR-triaxial cells are lower. The detailed geological mapping of the borehole indicated relationships between stress and geology. With regard to borehole depth different zones of rock structure joint frequency, joint orientation, and orientation of microfissures as well as stress magnitude, stress direction, and degree of deformation anisotropy could be distinguished. (author) 4 tabs., 76 figs., 31 refs

  20. HGR: Flow models, dust cake and cleaning models for hot flue gas filters. Project part: Design, flow regimes and cleaning of dust cakes at high temperatures. Final report; HGR: Stroemungs-, Filterkuchen- und Abreinigungsmodelle fuer Heissgasfilter. Teilprojekt: Aufbau, Durchstroemung und Abreinigung von Filterkuchen bei hohen Temperaturen. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Hemmer, G.

    1998-12-31

    As separators for the dedusting of hot flue gases from pressurized coal combustion or from product gases of coal gasification there are in principle filtration and centrifugal force and electrical separators. In this project bases shall be determined for methods of interpretation, carcateristic quantities and guide values for the hot gas filtration. As primary sizes for the interpretation to filter plants the pressure drop of dust cakes and filter elements on one hand and the forces necessary for regeneration on the other hand are of fundamental importance. Measurements were carried out at a high temperature filtration unit and at a laboratory filter plant and completed at a high temperature shear cell and a dilatometer. It was shown that the material composition of the dusts has a very decisive influence. Furthermore, the relative humidity has a considerable influence at ambient temperature. Aims of further examinations should therefore be the quantification of the material influences and the meaning of water vapour at high temperatures in order to be able to develop methods of interpretation for hot gas filters. (orig.) [Deutsch] Als Abscheideprinzipien fuer die Entstaubung von heissen Rauchgasen aus der Kohledruckverbrennung oder von Produktgasen aus der Kohlevergasung kommen Filtrations-, Fliehkraft- und elektrische Abscheider in Frage. In diesem Projekt sollen fuer die Heissgasfiltration Grundlagen fuer die Auslegungsmethoden, Kenngroessen und Richtwerte ermittelt werden. Als Primaergroessen fuer die Auslegung von Filteranlagen sind der Druckverlust von Staubkuchen und Filterelement einerseits und die zur Abreinigung noetige Abreinigungsintensitaet andererseits einzuschaetzen. Dabei wurden Messungen an einer Hochtemperaturfiltrationsanlage und einer Laborfilteranlage durchgefuehrt und durch Untersuchungen an einer Hochtemperaturscherzelle und einem Dilatometer ergaenzt. Es zeigte sich, dass die stoffliche Zusammensetzung der Staeube einen sehr entscheidenden

  1. Investigations of glass sealing and reactive air brazing materials for joining high temperature solid oxide fuel cells by dilatometric examinations; Anwendung dilatometrischer Messungen bei der Entwicklung von Glasloten und reaktiven Metallloten zum Fuegen von Hochtemperaturbrennstoffzellen

    Energy Technology Data Exchange (ETDEWEB)

    Reichle, M.S. [Parker Hannifin GmbH, Bietigheim-Bissingen (Germany); Federmann, D. [Forschungszentrum Juelich GmbH, ZAT, Juelich (Germany); Reisgen, U. [RWTH Aachen University, ISF, Aachen (Germany); Koppitz, T.

    2011-03-15

    shrinkage processes in the glass sealant joints are simulated and measured in the {mu}m range using a special dilatometer. In this way, the amount of glass sealant - which is decisive for tightness and bonding - and the process parameters can be determined in advance. With a vertical dilatometer, the melting behaviour of the reactive silver filler metals is examined with respect to melting point shift, viscosity and void ratio, and as a function of the metal additives (Al) and the process atmosphere.

  2. Report on in-situ studies of flash sintering of uranium dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Raftery, Alicia Marie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-01-24

    Flash sintering is a novel type of field assisted sintering that uses an electric field and current to provide densification of materials on very short time scales. The potential for field assisted sintering techniques to be used in producing nuclear fuel is gaining recognition due to the potential economic benefits and improvements in material properties. The flash sintering behavior has so far been linked to applied and material parameters, but the underlying mechanisms active during flash sintering have yet to be identified. This report summarizes the efforts to investigate flash sintering of uranium dioxide using dilatometer studies at Los Alamos National Laboratory and two separate sets of in-situ studies at Brookhaven National Laboratory’s NSLS-II XPD-1 beamline. The purpose of the dilatometer studies was to understand individual parameter (applied and material) effects on the flash behavior and the purpose of the in-situ studies was to better understand the mechanisms active during flash sintering. As far as applied parameters, it was found that stoichiometry, or oxygen-to-metal ratio, has a significant effect on the flash behavior (time to flash and speed of flash). Composite systems were found to have degraded sintering behavior relative to pure UO2. The critical field studies are complete for UO2.00 and will be analyzed against an existing model for comparison. The in-situ studies showed that the strength of the field and current are directly related to the sample temperature, with temperature-driven phase changes occurring at high values. The existence of an ‘incubation time’ has been questioned, due to a continuous change in lattice parameter values from the moment that the field is applied. Some results from the in-situ experiments, which should provide evidence regarding ion migration, are still being analyzed. Some preliminary conclusions can be made from these results with regard to using field assisted sintering to

  3. Characterization of Two Different Clay Materials by Thermogravimetry (TG), Differential Scanning Calorimetry (DSC), Dilatometry (DIL) and Mass Spectrometry (MS) - 12215

    Energy Technology Data Exchange (ETDEWEB)

    Post, Ekkehard [NETZSCH Geraetebau GmbH, Wittelsbacherstrasse 42, 95100 Selb (Germany); Henderson, Jack B. [NETZSCH Instruments North America, LLC, 129 Middlesex Turnpike, Burlington, MA 01803 (United States)

    2012-07-01

    An illitic clay containing higher amounts of organic materials was investigated by dilatometry, thermogravimetry and differential scanning calorimetric. The evolved gases were studied during simultaneous TG-DSC (STA) and dilatometer measurements with simultaneous mass spectrometry in inert gas and oxidizing atmosphere. The dilatometer results were compared with the STA-MS results which confirmed and explained the reactions found during heating of the clay, like dehydration, dehydroxylation, shrinkage, sintering, quartz phase transition, combustion or pyrolysis of organics and the solid state reactions forming meta-kaolinite and mullite. The high amount of organic material effects in inert gas atmosphere most probably a reduction of the oxides which leads to a higher mass loss than in oxidizing atmosphere. Due to this reduction an additional CO{sub 2} emission at around 1000 deg. C was detected which did not occur in oxidizing atmosphere. Furthermore TG-MS results of a clay containing alkali nitrates show that during heating, in addition to water and CO{sub 2}, NO and NO{sub 2} are also evolved, leading to additional mass loss steps. These types of clays showed water loss starting around 100 deg. C or even earlier. This relative small mass loss affects only less shrinkage during the expansion of the sample. The dehydroxylation and the high crystalline quartz content result in considerable shrinkage and expansion of the clay. During the usual solid state reaction where the clay structure collapses, the remaining material finally shrinks down to a so-called clinker. With the help of MS the TG steps can be better interpreted as the evolved gases are identified. With the help of the MS it is possible to distinguish between CO{sub 2} and water (carbonate decomposition, oxidation of organics or dehydration/dehydroxylation). The MS also clearly shows that mass number 44 is found during the TG step of the illitic clay at about 900 deg. C in inert gas, which was interpreted

  4. Synthesis and characterization of nanocomposite powders of calcium phosphate/silica-gel; Sintese e caracterizacao de pos nanoestruturados de fosfato de calcio/silica-gel

    Energy Technology Data Exchange (ETDEWEB)

    Muller, D.T.; Delima, S.A. [Universidade do Estado de Santa Catarina (UDESC), Joinville, SC (Brazil). Dept. de Engenharia Mecanica; Santos, R.B.M.; Camargo, N.H.A., E-mail: dem2nhac@joinville.udesc.b [Universidade do Estado de Santa Catarina (UDESC), Joinville, SC (Brazil). Programa de Pos Graduacao em Ciencia e Engenharia de Materiais

    2009-07-01

    In the recent years ceramics of calcium phosphate are pointed out as an outstanding material in substitution and regeneration in defects from osseous tissue, in reason of their similar mineralogical characteristics of apatite of bone structure. However, the challenge with phosphate calcium ceramics find out about the mechanical properties and the development of biomaterials similar of the bone structure, what sometimes is not so easy, about fragile materials. The aim of this work focused in synthesis and characterization nanocomposites powders of calcium phosphate/silica-gel with percentages 1, 2, 3 e 5% of nanometric silica. The method synthesis used for the compositions elaboration was dissolution-precipitation. The presented results are related with the optimization to method elaboration of nanostructured powders, the mineralogical characterization with X-ray diffraction, thermal behavior with thermal differential analysis, differential scanning calorimetry here is ADT and dilatometer. The scanning electronic microscopy was used to help of morphological characterization the nanostructured powders and the surfaces from body test recovered from the mechanical test. (author)

  5. Cracking and healing behavior of UO2 as related to pellet-cladding mechanical interaction. Interim report, July 1976

    International Nuclear Information System (INIS)

    Kennedy, C.R.; Yaggee, F.L.; Voglewede, J.C.; Kupperman, D.S.; Wrona, B.J.; Ellingson, W.A.; Johanson, E.; Evans, A.G.

    1976-10-01

    A direct-electrical-heating apparatus has been designed and fabricated to investigate those nuclear-fuel-related phenomena involved in the gap closure-bridging annulus formation mechanism that can be reproduced in an out-of-reactor environment. Prototypic light-water-reactor UO 2 fuel-pellet temperature profiles have been generated utilizing high flow rates (approximately 700 liters/min) of helium coolant gas, and a recirculating system has been fabricated to permit tests of up to 1000 h. Simulated light-water-reactor single- and multiple-thermal-cycle experiments will be conducted on both unclad and ceramic (fused silica) clad UO 2 pellet stacks. A laser dilatometer with a resolution of 1.27 x 10 -2 mm (5 x 10 -4 in.) is used to measure pellet dimensional increase continuously during thermal cycling. Acoustic emissions from thermal-gradient cracking have been detected and correlated with crack length and crack area. The acoustic emissions are monitored continuously to provide instantaneous information about thermal-gradient cracking. Posttest metallography and fracture-mechanics measurements are utilized to characterize cracking and crack healing

  6. Effect of bainitic transformation during BQ&P process on the mechanical properties in an ultrahigh strength Mn-Si-Cr-C steel

    Energy Technology Data Exchange (ETDEWEB)

    Gui, Xiaolu [Beijing Jiaotong University, School of Mechanical, Electronic and Control Engineering, Material Science & Engineering Research Center, Beijing 100044, People’ Republic of China (China); Gao, Guhui, E-mail: gaogh@bjtu.edu.cn [Beijing Jiaotong University, School of Mechanical, Electronic and Control Engineering, Material Science & Engineering Research Center, Beijing 100044, People’ Republic of China (China); Guo, Haoran; Zhao, Feifan; Tan, Zhunli [Beijing Jiaotong University, School of Mechanical, Electronic and Control Engineering, Material Science & Engineering Research Center, Beijing 100044, People’ Republic of China (China); Bai, Bingzhe [Beijing Jiaotong University, School of Mechanical, Electronic and Control Engineering, Material Science & Engineering Research Center, Beijing 100044, People’ Republic of China (China); Tsinghua University, Key Laboratory of Advanced Material, School of Material Science & Engineering, Beijing 100084, People’ Republic of China (China)

    2017-01-27

    A medium carbon Mn-Si-Cr alloyed steel was treated by a novel bainite-based quenching and partitioning (BQ&P) process: after full austenization, the steel was firstly austempered at 300 °C, 320 °C, 340 °C, 360 °C and 380 °C for 30 min, and then quenched to 120 °C, followed by partitioning at 360 °C for 45 min. The multiphase microstructures containing carbide-free bainite (CFB, bainitic ferrite lath plus filmy retained austenite), martensite and retained austenite were characterized by optical microscope, scanning electron microscopy, transmission electron microscopy, X-ray diffraction and dilatometer analysis. An optimum combination of strength and ductility was achieved in the BQ&P steel when the bainitic austempering temperature is 360 °C (ultimate tensile strength: 1495 MPa; uniform elongation and total elongation: 26.2% and 31.8%; the reduction of area: 47.9%). Besides the transformation-induced plasticity effect of the retained austenite and the composite effect of the multiphase after BQ&P treatment, the formation of carbide free bainite also plays a significant role on the enhanced mechanical properties. The carbide-free bainite could improve the damage resistance of the multiphase due to the additional strain-hardening capacity within the local plasticity deformation zone near the tip of micro-cracks. In this case, the fraction and distribution of CFB should be controlled properly and the macrosegregation should be avoided.

  7. Structural characterization of “carbide-free” bainite in a Fe–0.2C–1.5Si–2.5Mn steel

    Energy Technology Data Exchange (ETDEWEB)

    Hofer, Christina, E-mail: christina.hofer@unileoben.ac.at [Department of Physical Metallurgy and Materials Testing, Montanuniversitaet Leoben, Franz-Josef-Straße 18, 8700 Leoben (Austria); Leitner, Harald [Böhler Edelstahl GmbH & Co KG, Mariazeller Straße 25, 8605 Kapfenberg (Austria); Winkelhofer, Florian [voestalpine Stahl Linz GmbH, voestalpine-Straße 3, 4020 Linz (Austria); Clemens, Helmut; Primig, Sophie [Department of Physical Metallurgy and Materials Testing, Montanuniversitaet Leoben, Franz-Josef-Straße 18, 8700 Leoben (Austria)

    2015-04-15

    Low-alloyed, low C containing carbide-free bainitic steels are attractive candidates for applications in the automotive industry due to their well-balanced combination of high strength and ductility achieved in an economic way. In this work, their complex microstructure consisting of a mixture of bainitic ferrite, austenite with different morphologies and stabilities, martensite, M/A constituent and a few carbides has been investigated with metallographic and high-resolution techniques. After specific isothermal heat treatments in a dilatometer, a combination of LePera and Nital etching was applied to distinguish between bainite and martensite. Site-specific atom probe tips were prepared by means of scanning electron microscopy, electron backscatter diffraction and focused ion beam, revealing that “carbide-free” bainite consists of C depleted bainitic ferrite, C enriched retained austenite and occasional ε-carbides. Furthermore, it was found that the M/A constituent is highly dislocated and mainly martensitic. Its C content is increased compared to the nominal composition, but below the values obtained for retained austenite, explaining the lower transformation resistance. - Highlights: • Detailed top-down characterization of low C “carbide-free” bainitic steel • APT of all constituents in “carbide-free” bainite • Identification of ε-carbide based on its C content determined by APT • M/A constituent is mainly martensitic with austenitic areas at the boundaries • Lower C content of M/A constituent explains its lower stability.

  8. Microstructural Evolution of Inverse Bainite in a Hypereutectoid Low-Alloy Steel

    Science.gov (United States)

    Kannan, Rangasayee; Wang, Yiyu; Li, Leijun

    2017-12-01

    Microstructural evolution of inverse bainite during isothermal bainite transformation of a hypereutectoid low-alloy steel at 773 K (500 °C) was investigated through a series of interrupted isothermal experiments using a quench dilatometer. Microstructural characterization revealed that the inverse bainitic transformation starts by the nucleation of cementite (Fe3C) from parent austenite as a midrib in the bainitic microstructure. The inverse bainite becomes "degenerated" to typical upper bainite at prolonged transformation times. Crystallographic orientation relationships between the individual phases of inverse bainite microstructure were found to obey { _{γ } || _{θ } } { _{α } || _{θ } } { _{γ } || _{α } } 111_{γ } || { \\overline{2} 21} _{θ } } { 110} _{α } || { \\overline{2} 21} _{θ } } { 111} _{γ } || { 110 } _{α } {111} _{γ } || {211} _{θ } {110} _{α } || {211} _{θ } Furthermore, the crystallographic orientation deviations between the individual phases of inverse bainite microstructure suggest that the secondary carbide nucleation occurs from the inverse bainitic ferrite. Thermodynamic driving force calculations provide an explanation for the observed nucleation sequence in inverse bainite. The degeneracy of inverse bainite microstructure to upper bainite at prolonged transformation times is likely due to the effects of cementite midrib dissolution at the early stage and secondary carbide coarsening at the later stage.

  9. On the sintering behaviour of steel bonded TiC-Cr3C2 and TiC-Cr3C2-WC mixed carbides

    International Nuclear Information System (INIS)

    Stojanov, L.G.; Exner, H.E.

    1978-01-01

    Powder mixtures of TiC+Cr 3 C 2 and TiC+Cr 3 C 2 + WC were hot pressed to nearly full density. The lattice parameter of the resulting cubic mixed crystal decreases linearly with increasing additions of Cr 3 C 2 and (Cr 3 C 2 +WC 1:1). Microhardness increases with Cr 3 C 2 content up to 20 wt.%. By addition of WC, microhardness is increased further and reaches a maximum value of approx. 38 000 MN/m 2 for 20 wt.% Cr 3 C 2 and 20 wt.% WC. From these solid solutions powder compositions of Ferro-TiC type were produced by milling with 55 wt.% Fe and 0.4 wt.% C. The sintering behaviour of these powders was studied in a vacuum dilatometer. The pronounced increase of shrinkage by Cr 3 C 2 and higher amounts of Cr 3 C 2 +WC dissolved in TiC previous to binder phase melting is attributed to the increased solubility of the carbide in solid iron. Presintering at 700 0 C in hydrogen has a negative influence on sintering activity and requires much higher temperatures for complete densification during subsequent vacuum sintering. (orig.) [de

  10. Anisotropic pressure dependence of Tc in single-crystal YBa2Cu3O7 via thermal expansion

    International Nuclear Information System (INIS)

    Meingast, C.; Blank, B.; Buerkle, H.; Obst, B.; Wolf, T.; Wuehl, H.; Selvamanickam, V.; Salama, K.

    1990-01-01

    High-resolution anisotropic-thermal-expansion measurements of single-crystalline and oriented-grained YBa 2 Cu 3 O 7 at the superconducting transition are presented for the first time. Discontinuities in the thermal-expansion coefficient α ab [Δα ab =(15--23)x10 -8 K -1 ], measured with a capacitance dilatometer, are found to occur in both samples. No discontinuity in α c (|Δα c | -8 K -1 ) is observed in either sample, although α c (T) shows a distinct change of slope at T c . The specific-heat discontinuity ΔC p of both samples was also measured and is used, along with the Δα's, to calculate the dependence of T c on uniaxial pressure and uniaxial strain to first order. T c is predicted to increase with pressure applied perpendicular to the c axis (dT c /dp ab =0.04--0.09 K/kbar) and to be insensitive to pressure parallel to the c axis. Uniaxial strain, on the other hand, is found to increase T c about equally in both directions

  11. NiCr (x) Fe2-x O-4 as cathode materials for electrochemical reduction of NO (x)

    DEFF Research Database (Denmark)

    Bræstrup, Frantz Radzik; Kammer Hansen, Kent

    2010-01-01

    Solid solutions of spinel-type oxides with the composition NiCr x Fe2-x O4 (x = 0.0, 0.5, 1.0, 1.5, 2.0) were prepared with the glycine–nitrate combustion synthesis. Four-point DC resistivity measurements show an increase in the conductivity as more Cr is introduced into the structure, whereas...... dilatometer measurements show that the linear thermal expansion decreases with increasing Cr content. The oxides were used as electrode materials in a pseudo-three-electrode setup in the temperature range of 300–600 °C. Cyclic voltammetry and electrochemical impedance spectroscopy were used to characterize...... the electrochemical behavior in 1% NO, 1% NO2, and 10% O2. NiCr2O4 shows high activity in NO and NO2 relative to O2 and can therefore be considered as a possible electrode material. Peaks were detected in the voltammograms recorded on NiCr2O4 in 1% NO. The origin of the peaks seems to be related to the oxidation...

  12. Mechanics of brazed joints and compliant layers in high heat flux components

    International Nuclear Information System (INIS)

    Lovato, G.; Moret, F.; Chaumat, G.; Cailletaud, G.; Pilvin, P.

    1995-01-01

    Soft layers are of great interest for the joining of dissimilar materials like beryllium, tungsten or carbone base refractory tiles for plasma interface and cooled structures made of copper or molybdenum. Soft layers reduce the residual and in-service stress/strain level without reducing the thermal capability. Thin soft layers interfaces are produced during the brazing or HIP bonding cycles. However, the numerical modelling of the mechanical effect of such soft layers remains largely inaccurate. The camber of [CFC tiles (A05, N11, N112)/Ag-Cu-Ti filler metal/OFHC or TZM substrate] assemblies is recorded during the whole brazing thermal cycle and subsequent thermal fatigue cycles using a special vertical dilatometer. An inverse method based on Finite Element modelling of the samples is used to determine the joint constitutive law. Then, by comparing experiments and FEM calculations, the effects of distributed damage of the CFC and of the strain hardening and thermal softening of OFHC on the in-service stress/strain state of the component are observed. (orig.)

  13. Measurement and correlation of excess molar volumes for mixtures of 1-propanol and aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Gahlyan, Suman; Rani, Manju; Maken, Sanjeev Kumar [Deenbandhu Chhotu Ram University of Science and Technology, Murthal (India); Lee, Inkyu; Moon, Il [Yonsei University, Seoul (Korea, Republic of)

    2015-01-15

    Excess molar volumes (V{sub m}{sup E} ) have been measured at 303.15 K for 1-propanol+benzene or toluene or o- or m- or p-xylene mixtures using V-shape dilatometer. The V{sub m}{sup E} values, for an equimolar composition, vary in the order: benzene>toluene-m-xylene>o-xylene>p-xylene. The V{sub m}{sup E} data have been used to calculate partial molar volumes, excess partial molar volumes, and apparent molar volumes of 1-propanol and aromatic hydrocarbons over the entire range of composition. The excess volume data have also been interpreted in terms of graph-theoretical approach and Prigogine-Flory-Patterson theory (PFP). While PFP theory fails to predict the V{sub m}{sup E} values for systems with s-shaped V{sub m}{sup E} versus x{sub 1} graph, the V{sub m}{sup E} values calculated by graph theory compare reasonably well with the corresponding experimental values. This graph theory analysis has further yielded information about the state of aggregation of pure components as well as of the mixtures.

  14. Role of Nb in low interstitial 13Cr super martensitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Ma, X.P.; Wang, L.J. [Key Laboratory for Anisotropy and Texture of Materials, Northeastern University, Shenyang 110004 (China); Liu, C.M., E-mail: cmliu@mail.neu.edu.cn [Key Laboratory for Anisotropy and Texture of Materials, Northeastern University, Shenyang 110004 (China); Subramanian, S.V. [Department of Materials Science and Engineering, McMaster University, Hamilton, L8S-4L7 (Canada)

    2011-08-25

    Highlights: {yields} Nb retards the kinetics of reversed austenite formation. {yields} Nb suppresses the occurrence of Cr rich precipitates. {yields} Nano-scale precipitates contribute to the significant increase in strength. - Abstract: The effect of adding 0.1 wt% Nb to low interstitial (N 0.01 wt%, C 0.01 wt%) 13Cr super martensitic stainless steel (SMSS) on solid phase transformation and microstructures achieved by normalizing and tempering was investigated using dilatometer, electron backscattered diffraction (EBSD), transmission electron microscope (TEM), X-ray diffraction (XRD), and its consequence on mechanical properties was examined to clarify the role of Nb in low interstitial martensitic stainless steel. Nb was found to retard kinetics of reversed austenite formation during tempering and to suppress the occurrence of Cr rich precipitates. The measurement of mechanical properties shows that while the strength properties were significantly increased by nano-scale precipitates enriched in Nb in the steel with 0.10 wt% Nb, the ductility and toughness properties were restored by optimum volume fraction of retained austenite. Excellent strength and adequate toughness properties were obtained by tempering the steel with 0.10 wt% Nb and low interstitial (N 0.01 wt%, C 0.01 wt%) steel at 600 deg. C.

  15. Hot compression deformation behavior of AISI 321 austenitic stainless steel

    Science.gov (United States)

    Haj, Mehdi; Mansouri, Hojjatollah; Vafaei, Reza; Ebrahimi, Golam Reza; Kanani, Ali

    2013-06-01

    The hot compression behavior of AISI 321 austenitic stainless steel was studied at the temperatures of 950-1100°C and the strain rates of 0.01-1 s-1 using a Baehr DIL-805 deformation dilatometer. The hot deformation equations and the relationship between hot deformation parameters were obtained. It is found that strain rate and deformation temperature significantly influence the flow stress behavior of the steel. The work hardening rate and the peak value of flow stress increase with the decrease of deformation temperature and the increase of strain rate. In addition, the activation energy of deformation ( Q) is calculated as 433.343 kJ/mol. The microstructural evolution during deformation indicates that, at the temperature of 950°C and the strain rate of 0.01 s-1, small circle-like precipitates form along grain boundaries; but at the temperatures above 950°C, the dissolution of such precipitates occurs. Energy-dispersive X-ray analyses indicate that the precipitates are complex carbides of Cr, Fe, Mn, Ni, and Ti.

  16. Linear Thermal Expansion Measurements of Lead Magnesium Niobate (PMN) Electroceramic Material for the Terrestrial Planet Finder Coronagraph

    Science.gov (United States)

    Karlmann, Paul B.; Halverson, Peter G.; Peters, Robert D.; Levine, Marie B.; VanBuren, David; Dudik, Matthew J.

    2005-01-01

    Linear thermal expansion measurements of nine samples of Lead Magnesium Niobate (PMN) electroceramic material were recently performed in support of NASA's Terrestrial Planet Finder Coronagraph (TPF-C) mission. The TPF-C mission is a visible light coronagraph designed to look at roughly 50 stars pre- selected as good candidates for possessing earth-like planets. Upon detection of an earth-like planet, TPF-C will analyze the visible-light signature of the planet's atmosphere for specific spectroscopic indicators that life may exist there. With this focus, the project's primary interest in PMN material is for use as a solid-state actuator for deformable mirrors or compensating optics. The nine test samples were machined from three distinct boules of PMN ceramic manufactured by Xinetics Inc. Thermal expansion measurements were performed in 2005 at NASA Jet Propulsion Laboratory (JPL) in their Cryogenic Dilatometer Facility. All measurements were performed in vacuum with sample temperature actively controlled over the range of 270K to 3 10K. Expansion and contraction of the test samples with temperature was measured using a JPL developed interferometric system capable of sub-nanometer accuracy. Presented in this paper is a discussion of the sample configuration, test facilities, test method, data analysis, test results, and future plans.

  17. A study on the thermal expansion characteristics of simulated spent fuel and simulated DUPIC fuel

    International Nuclear Information System (INIS)

    Kang, Kweon Ho; Ryu, H. J.; Kim, H. S.; Song, K. C.; Yang, M. S.

    2001-10-01

    Thermal expansions of simulated spent PWR fuel and simulated DUPIC fuel were studied using a dilatometer in the temperature range from 298 to 1900 K. The densities of simulated spent PWR fuel and simulated DUPIC fuel used in the measurement were 10.28 g/cm3 (95.35 % of TD) and 10.26 g/cm3 (95.14 % of TD), respectively. Their linear thermal expansions of simulated fuels are higher than that of UO2, and the difference between these fuels and UO2 increases progressively as temperature increases. However, the difference between simulated spent PWR fuel and simulated DUPIC fuel can hardly be observed. For the temperature range from 298 to 1900 K, the values of the average linear thermal expansion coefficients for simulated spent PWR fuel and simulated DUPIC fuel are 1.391 10-5 and 1.393 10-5 K-1, respectively. As temperature increases to 1900 K, the relative densities of simulated spent PWR fuel and simulated DUPIC fuel decrease to 93.81 and 93.76 % of initial densities at 298 K, respectively

  18. Development of an ultrasensitive interferometry system as a key to precision metrology applications

    Science.gov (United States)

    Gohlke, Martin; Schuldt, Thilo; Weise, Dennis; Johann, Ulrich; Peters, Achim; Braxmaier, Claus

    2009-06-01

    We present a symmetric heterodyne interferometer as a prototype of a highly sensitive translation and tilt measurement system. This compact optical metrology system was developed over the past several years by EADS Astrium (Friedrichshafen) in cooperation with the Humboldt-University (Berlin) and the university of applied science Konstanz (HTWG-Konstanz). The noise performance was tested at frequencies between 10-4 and 3 Hz, the noise levels are below 1 nm/Hz 1/2 for translation and below 1 μrad/Hz1/2, for tilt measurements. For frequencies higher than 10 mHz noise levels below 5pm/Hz1/2 and 4 nrad/Hz1/2 respectively, were demonstrated. Based on this highly sensitive metrology system we also developed a dilatometer for the characterization of the CTE (coefficient of thermal expansion) of various materials, i.e. CFRP (carbon fiber reinforced plastic) or Zerodur. The currently achieved sensitivity of these measurements is better than 10-7 K-1. Future planned applications of the interferometer include ultra-high-precision surface profiling and characterization of actuator noise in low-noise opto-mechanics setups. We will give an overview of the current experimental setup and the latest measurement results.

  19. Low-temperature thermal expansion of pure and inert gas-doped fullerite C sub 6 sub 0

    CERN Document Server

    Aleksandrovskii, A N; Eselson, V B; Gavrilko, V G; Manzhelii, V G; Udovidchenko, B G; Bakai, A S; Gadd, G E; Moricca, S; Sundqvist, B

    2003-01-01

    The low temperature (2-24 K) thermal expansion of pure (single-crystal and polycrystalline) C sub 6 sub 0 and polycrystalline C sub 6 sub 0 intercalated with He, Ne, Ar, and Kr has been investigated using the high-resolution capacitance dilatometer. The investigation of the time dependence of the sample length variations DELTA L(t) on heating by DELTA T shows that the thermal expansion is determined by the sum of positive and negative contributions, which have different relaxation times. The negative thermal expansion usually prevails at helium temperatures. The positive expansion is connected with the phonon thermalization of the system. The negative expansion is caused by reorientation of the C sub 6 sub 0 molecules. It is assumed that the reorientation is of a quantum character. The inert gas impurities affect the reorientation of the C6 sub sub 0 molecules very strongly, especially at liquid helium temperatures. A temperature hysteresis of the thermal expansion coefficient of Kr- and He-C sub 6 sub 0 solu...

  20. Porous composite with negative thermal expansion obtained by photopolymer additive manufacturing

    Directory of Open Access Journals (Sweden)

    Akihiro Takezawa

    2015-07-01

    Full Text Available Additive manufacturing (AM could be a novel method of fabricating composite and porous materials having various effective performances based on mechanisms of their internal geometries. Materials fabricated by AM could rapidly be used in industrial application since they could easily be embedded in the target part employing the same AM process used for the bulk material. Furthermore, multi-material AM has greater potential than usual single-material AM in producing materials with effective properties. Negative thermal expansion is a representative effective material property realized by designing a composite made of two materials with different coefficients of thermal expansion. In this study, we developed a porous composite having planar negative thermal expansion by employing multi-material photopolymer AM. After measurement of the physical properties of bulk photopolymers, the internal geometry was designed by topology optimization, which is the most effective structural optimization in terms of both minimizing thermal stress and maximizing stiffness. The designed structure was converted to a three-dimensional stereolithography (STL model, which is a native digital format of AM, and assembled as a test piece. The thermal expansions of the specimens were measured using a laser scanning dilatometer. Negative thermal expansion corresponding to less than −1 × 10−4 K−1 was observed for each test piece of the N = 3 experiment.

  1. Thermophysical and mechanical characterization of advanced materials for the LHC collimation system

    CERN Document Server

    AUTHOR|(CDS)2129177; Guinchard, Michael

    The aim of the thesis is to describe the methods employed for the thermo-physical and mechanical characterization and to show the results of the campaign conducted over two ceramic matrix composites, CFC FS140® and MG-6403-Fc, which are candidates as jaws materials in the LHC collimation system. The work was conducted at the European Organization for Nuclear Research (CERN, Geneva), in the framework of the R&D activities done by the EN department. The goal of this project is to develop and characterize materials able to withstand highly energetic particles interactions to protect the accelerator’s components and to clean the beam. In the first part of the thesis, the instruments employed for the thermal and mechanical analysis are studied, from the mathematical models to the standard test methods. These instruments are: horizontal push-rod dilatometer, differential scanning calorimeter, laser flash apparatus and universal testing machine. The results of the analysis show lower thermal and electrical co...

  2. THERMOPHYSICAL AND MECHANICAL CHARACTERIZATION OF ADVANCED MATERIALS FOR THE LHC COLLIMATION SYSTEM

    CERN Document Server

    Bianchi, Laura

    2017-01-01

    The aim of the thesis is to describe the methods employed for the thermo-physical and mechanical characterization and to show the results of the campaign conducted over two ceramic matrix composites, CFC FS140® and MG-6403-Fc, which are candidates as jaws materials in the LHC collimation system. The work was conducted at the European Organization for Nuclear Research (CERN, Geneva), in the framework of the R&D activities done by the EN department. The goal of this project is to develop and characterize materials able to withstand highly energetic particles interactions to protect the accelerator’s components and to clean the beam. In the first part of the thesis, the instruments employed for the thermal and mechanical analysis are studied, from the mathematical models to the standard test methods. These instruments are: horizontal push-rod dilatometer, differential scanning calorimeter, laser flash apparatus and universal testing machine. The results of the analysis show lower thermal and electrical co...

  3. Mechanics of brazed joints and compliant layers in high heat flux components

    International Nuclear Information System (INIS)

    Lovato, G.; Moret, F.; Chaumat, G.

    1994-01-01

    Soft layers are of great interest for the joining of dissimilar materials like beryllium, tungsten or carbon base refractory tiles for plasma interface and cooled structures made of copper or molybdenum. Soft layers reduce the residual and in-service stress/strain level without reducing the thermal capability. Thin soft layers interfaces are produced during the brazing or HIP bonding cycles. However, the numerical modelling of the mechanical effect of such soft layers remains largely inaccurate. The camber of [CFC tiles (A05, N11, N112)/Ag-Cu-Ti filler metal/OFHC or TZM substrate] assemblies is recorded during the whole brazing thermal cycle and subsequent thermal fatigue cycles using a special vertical dilatometer. An inverse method based on Finite Element modelling of the samples is used to determine the joint constitutive law. Then, by comparing experiments and FEM calculations, the effects of distributed damage of the CFC and of the strain hardening and thermal softening of OFHC on the in-service stress/strain state of the component are observed. (authors). 5 refs., 7 figs

  4. Effects of Re concentration on the expansivity of NiRe alloys to 1200 K NULL

    Science.gov (United States)

    Babu, V. Suresh; Seehra, Mohindar S.

    1998-08-01

    Measurements of the thermal expansion 0953-8984/10/33/006/img1 and hence the coefficient of thermal expansion 0953-8984/10/33/006/img2 are reported for 0953-8984/10/33/006/img3 alloys (x = 0, 5, 8, 10, 12, 16 and 25%) in the temperature range of 300 to 1300 K using a dilatometer. Room temperature x-ray diffraction studies show that for 0953-8984/10/33/006/img4%, a small fraction of Re begins to precipitate out, in addition to the dominant face-centred cubic (fcc) phase whose lattice constant increases linearly with x. The variations of 0953-8984/10/33/006/img2 with x plotted at selected temperatures of 503, 903 and 1203 K shows that for 0953-8984/10/33/006/img6%, 0953-8984/10/33/006/img2 decreases with increasing x at 503 and 903 K, whereas it remains practically constant with x at 1203 K. The latter result is in agreement with the predictions of Mei et al (1994 Alloy Modeling and Design ed G M Stocks and P E A Turchi (Warrendale, PA: TMS Publishing)) using molecular dynamics simulations. The variation of 0953-8984/10/33/006/img2 with x shows a minimum at x = 12% at all temperatures. The possible role of shear stresses in the dendritic grain structure of these alloys on measured 0953-8984/10/33/006/img2 below 1000 K is discussed.

  5. Thermal expansion and magnetostriction of clathrate compound Pr3Pd20Ge6

    Science.gov (United States)

    Matsumoto, K.; Sekiguchi, Y.; Iwakami, O.; Ono, T.; Abe, S.; Ano, G.; Akatsu, M.; Mitsumoto, K.; Nemoto, Y.; Goto, T.; Takeda, N.; Kitazawa, H.

    2018-03-01

    In Pr3Pd20Ge6, the Pr ions are located at two different crystallographic sites, 4a and 8c site. Antiferro-quadrupole ordering (AFQ) of the 8c site occurs at 250 mK. Ac susceptibility measurement indicated that antiferromagnetic ordering (AFM) of the 4a site and Hyperfine-enhanced Pr nuclear magnetic ordering of the 8c site occur at 77 and 9 mK, respectively. To clarify the magnetic and quadrupole properties of Pr3Pd20Ge6, thermal expansion and magnetostriction measurements on single crystal sample were carried out along the [001] direction up to 8 T down to 500 μK using a capacitive dilatometer. In zero field, relative length change ΔL/L in [001] direction had a dip at AFQ and abrupt decrease at AFM ordering. From thermal expansion and isothermal magnetostriction measurements, magnetic phase diagram of Pr3Pd20Ge6 along [001] direction was obtained.

  6. Polymerization kinetics of monomers of importance in biomedicine investigated by γirradiation

    International Nuclear Information System (INIS)

    Bebe, S.; Monteiro, M.J.; Ganachaud, F.; Napper, D.H.; Gilbert, R.G.

    1998-01-01

    Gamma irradiation was used to initiate the polymerization of NIPAM in water below the LCST. Conversion as a function of time was followed with automated tracking dilatometry. The data were used to show that classical kinetics were obeyed. Relaxation experiments (i.e. where the dilatometer is removed from the γ source) then provide reliable values for the reactivity ratio, k i /k p , the ratio of the termination to propagation rate coefficients. It was found at a monomer concentration of 0.442 M, k i k p had a value of 8.1 at 27 deg C . This suggested that either k t was very low, perhaps because the radicals are constrained to some complexation or aggregation mechanism, or k p is extraordinarily high. Pulsed laser polymerizations (in conjunction with size exclusion chromatography, SEC) were performed to obtain accurate k p values for NIPAM in water over a temperature range below the LCST (2 - 27 deg C ). The main difficulty with most functional polymers is obtaining quantitative data from SEC. PNIPAM is no exception to the rule, and meticulous care in molecular weight analysis was necessary. Special insights were developed into sample preparation to obtain accurate molecular weight distributions (MWD). The value k p was found to be high, but not extraordinarily so, and hence the high value of k t must be due to a constrained polymer radical

  7. Sinterability and microstructure evolution during sintering of ferrous powder mixtures

    Directory of Open Access Journals (Sweden)

    Kétner Bendo Demétrio

    2013-01-01

    Full Text Available The present work is focused on ferrous powder metallurgy and presents some results of a development of a suitable masteralloy for use as an additive to iron powder for the production of sintered steels. The masteralloy was produced by melting a powder mixture containing approximately Fe + 20% Ni + 20% Mn + 20% Si + 1% C (wt%, in order to obtain a cast billet that was converted into fine powder by crushing and milling. It was observed presence of SiC in the masteralloy after melting that is undesirable in the alloy. Si element should be introduced by using ferrosilicon. Sintered alloys with distinct contents of alloying elements were prepared by mixing the masteralloy powder to plain iron powder. Samples were produced by die compaction of the powder mixtures and sintering at 1200 °C in a differential dilatometer in order to record their linear dimensional behaviour during heating up and isothermal sintering, aiming at studying the sinterability of the compacts. Microstructure development during sintering was studied by SEM, XRD and microprobe analyses.

  8. Influence of hot plastic deformation and cooling rate on martensite and bainite start temperatures in 22MnB5 steel

    International Nuclear Information System (INIS)

    Nikravesh, M.; Naderi, M.; Akbari, G.H.

    2012-01-01

    Highlights: ► Reduction of cooling rate, can cause to increase or decrease M s and M f . ► 40% hot plastic deformation hindered the martensitic transformation. ► Hot plastic deformation, caused to decrease M f and M s , while B s increased. ► The critical cooling rate increased 40 °C/s due to apply 40% hot deformation. - Abstract: During hot stamping process, hot forming, cooling and phase transformations are performed in a single step. As a matter of fact, multifunctional phenomena happen and affect each other. Among these phenomena, martensitic and bainitic transformations have the greatest importance. In the current research, the start temperatures of martensite and bainite of 22MnB5 boron steel have been measured in undeformed and 40% deformed conditions, and in various cooling rates from 0.4 °C/s to 100 °C/s by means of deformation dilatometer. It is concluded that, reduction of cooling rate, could bring about an increase or decrease in M s and M f , depending on other phases formation before martensite. Also, hot plastic deformation, hindered the martensitic transformation and decreased M f and M s especially at lower cooling rates, while B s increased. Furthermore, the critical cooling rate, increased about 40 °C/s by applying 40% hot plastic deformation.

  9. Investigation of the sinterability of ZrO_2 (Y_2O3_)-bioglass dental ceramics by dilatometry

    International Nuclear Information System (INIS)

    Bicalho, Luiz de Araujo; Barboza, Miguel Ribeiro Justino; Santos, Claudinei dos; Habibe, Alexandre Fernandes; Magnago, Roberto de Oliveira

    2013-01-01

    The objective of this work is to study by dilatometry, the liquid phase sintering of ZrO_2 ceramics using bioglass as sintering additive. Y_2 O_3 - stabilized ZrO_2 powders were mixed with 3, 5 and 10 wt% of bioglass with the composition based on 3CaOP_2 O_5 -MgO-SiO_2 system. Specimens were prepared by cold uniaxial pressing under 80MPa and the green relative density was determined. The sintering behavior was studied by measuring the linear shrinkage of samples in a dilatometer in relation to the temperature. The heating and cooling rates used in this study were 10 deg C/min and the maximum sintering temperatures was 1300 deg C with a 120 min isothermal holding time. The results of the shrinkage and shrinkage rates in regard of the sintering temperature and time were related to the amount of bioglass added. The sintered samples were characterized by X-ray diffraction analysis and their relative density. SEM micrographs indicates similar microstructure, and an increase of bioglass content leads to increasing of monoclinic ZrO_2 phase content. The dilatometry results indicate a reduction of the temperature where a maximum shrinkage rate occurs, as function of bioglass increasing. Furthermore, the use of liquid phase reduces the maximum sintering temperature of 1447 deg C to 1250-1280 deg C. (author)

  10. Effect of the addition of Na2O on the thermal properties and chemical durability of glasses of iron and uranium phosphates

    International Nuclear Information System (INIS)

    Arboleda Zuluaga, P.A; Rodriguez, D.S; Gonzalez Oliver, C; Rincon Lopez, J.M; Soldera, F

    2012-01-01

    A series of glass compositions including (54,6-73,5P 2 O 5 .14-22Fe 2 O 3.x Na 2 O.2,8-4,25 UO 2 ) %mol. x=0-28,4 were studied in function of sodium oxide content for the thermal properties and chemical durability. By means differential dilatometer measurements was possible establish the variation of Tg, and α Tsoft and analysis of the kinetics of sintering by means of High Temperature Microscopy (MAT) and dilatometric data of pressed pellets. The presence of modifier oxides in the structure of iron phosphate glasses causes slightly onset sintering anticipation in almost 25 o C The chemical durability was estimated performing the named Product Consistency Test (PCT-B) focused on determining the resistance of glasses for nuclear wastes. These glasses exhibit good chemical durability but it is significant impaired by the addition of x≥6wt%Na 2 O. It is aimed to achieve more stable compositions and get glass matrixes able to contain more uranium oxides allowing evaluating the potential application of these iron phosphate glasses for special, industrial and nuclear waste immobilization

  11. Shock and Detonation Physics at Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Robbins, David L [Los Alamos National Laboratory; Dattelbaum, Dana M [Los Alamos National Laboratory; Sheffield, Steve A [Los Alamos National Laboratory

    2012-08-22

    WX-9 serves the Laboratory and the Nation by delivering quality technical results, serving customers that include the Nuclear Weapons Program (DOE/NNSA), the Department of Defense, the Department of Homeland Security and other government agencies. The scientific expertise of the group encompasses equations-of-state, shock compression science, phase transformations, detonation physics including explosives initiation, detonation propagation, and reaction rates, spectroscopic methods and velocimetry, and detonation and equation-of-state theory. We are also internationally-recognized in ultra-fast laser shock methods and associated diagnostics, and are active in the area of ultra-sensitive explosives detection. The facility capital enabling the group to fulfill its missions include a number of laser systems, both for laser-driven shocks, and spectroscopic analysis, high pressure gas-driven guns and powder guns for high velocity plate impact experiments, explosively-driven techniques, static high pressure devices including diamond anvil cells and dilatometers coupled with spectroscopic probes, and machine shops and target fabrication facilities.

  12. Measurement and correlation of excess molar volumes for mixtures of 1-propanol and aromatic hydrocarbons

    International Nuclear Information System (INIS)

    Gahlyan, Suman; Rani, Manju; Maken, Sanjeev Kumar; Lee, Inkyu; Moon, Il

    2015-01-01

    Excess molar volumes (V m E ) have been measured at 303.15 K for 1-propanol+benzene or toluene or o- or m- or p-xylene mixtures using V-shape dilatometer. The V m E values, for an equimolar composition, vary in the order: benzene>toluene-m-xylene>o-xylene>p-xylene. The V m E data have been used to calculate partial molar volumes, excess partial molar volumes, and apparent molar volumes of 1-propanol and aromatic hydrocarbons over the entire range of composition. The excess volume data have also been interpreted in terms of graph-theoretical approach and Prigogine-Flory-Patterson theory (PFP). While PFP theory fails to predict the V m E values for systems with s-shaped V m E versus x 1 graph, the V m E values calculated by graph theory compare reasonably well with the corresponding experimental values. This graph theory analysis has further yielded information about the state of aggregation of pure components as well as of the mixtures

  13. Cermet fuel for fast reactor – Fabrication and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Sudhir, E-mail: sudhir@barc.gov.in [Radiometallurgy Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Kutty, P.S.; Kutty, T.R.G. [Radiometallurgy Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Das, Shantanu [Uranium Extraction Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Dey, G.K. [Materials Science Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Kumar, Arun [Radiometallurgy Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

    2013-11-15

    (U, Pu)O{sub 2} ceramic fuel is the well-established fuel for the fast reactors and (U, Pu, Zr) metallic fuel is the future fuel. Both the fuels have their own merits and demerits. Optimal solution may lie in opting for a fuel which combines the favorable features of both fuel systems. The choice may be the use of cermet fuel which can be either (U, PuO{sub 2}) or (Enriched U, UO{sub 2}). In the present study, attempt has been made to fabricate (Natural U, UO{sub 2}) cermet fuel by powder metallurgy route. Characterization of the fuel has been carried out using dilatometer, differential thermal analyzer, X-ray diffractometer, and Scanning Electron Microscope. The results show a high solidus temperature, high thermal expansion, presence of porosities, etc. in the fuel. The thermal conductivity of the fuel has also been measured. X-ray diffraction study on the fuel compact reveals presence of α U and UO{sub 2} phases in the matrix of the fuel.

  14. Microstructural Characterization of the Heat-Affected Zones in Grade 92 Steel Welds: Double-Pass and Multipass Welds

    Science.gov (United States)

    Xu, X.; West, G. D.; Siefert, J. A.; Parker, J. D.; Thomson, R. C.

    2018-04-01

    The microstructure in the heat-affected zone (HAZ) of multipass welds typical of those used in power plants and made from 9 wt pct chromium martensitic Grade 92 steel is complex. Therefore, there is a need for systematic microstructural investigations to define the different regions of the microstructure across the HAZ of Grade 92 steel welds manufactured using the traditional arc welding processes in order to understand possible failure mechanisms after long-term service. In this study, the microstructure in the HAZ of an as-fabricated two-pass bead-on-plate weld on a parent metal of Grade 92 steel has been systematically investigated and compared to a complex, multipass thick section weldment using an extensive range of electron and ion-microscopy-based techniques. A dilatometer has been used to apply controlled thermal cycles to simulate the microstructures in distinctly different regions in a multipass HAZ using sequential thermal cycles. A wide range of microstructural properties in the simulated materials were characterized and compared with the experimental observations from the weld HAZ. It has been found that the microstructure in the HAZ can be categorized by a combination of sequential thermal cycles experienced by the different zones within the complex weld metal, using the terminology developed for these regions based on a simpler, single-pass bead-on-plate weld, categorized as complete transformation, partial transformation, and overtempered.

  15. Study of delayed behaviour of clays in deep geologic formations

    International Nuclear Information System (INIS)

    Rousset, G.; Bazargan, B.; Ouvry, J.F.; Bouilleau, M.

    1993-01-01

    This study is a cost-sharing contract with the European Atomic Energy Community within the framework of Research and Development Program on Management, Storage and Radioactive Waste Disposal. The aim of the work presented in this report is to study the time-dependent behaviour of deep clays in Laboratory or in situ, by means of tests of similar geometry, in order to get easy comparisons and to study scale effect. The cylindrical geometry has been chosen as it resembles in situ works (tunnels, galleries) more closely. The first part of the study concerns a new test on hollow-cylinder. The experimental system, set up specially for this study, has allowed to conduct experiments in which 3 loading parameters may be controlled independently. Different types of experiments can therefore be conducted to study various aspects of mechanical behavior of rocks. A comprehensive experimental program was conducted in the particular case of Boom clay. In the second part of the report devoted to in situ creep or relaxation dilatometer tests, by using new techniques or loading paths, it was shown that time-dependent convergence of boreholes can reach significant values, and is dependent on the direction of the borehole. The anisotropy of the initial state of stress was also put in evidence. The proposed constitutive model (part III) appears to be very suitable to explain the behavior of the Boom clay, in view of the experimental results. In particular, the scale effect is low for Boom clay. 15 refs., 58 figs., 10 tabs

  16. Sintering behavior and mechanical properties of a metal injection molded Ti–Nb binary alloy as biomaterial

    International Nuclear Information System (INIS)

    Zhao, Dapeng; Chang, Keke; Ebel, Thomas; Nie, Hemin; Willumeit, Regine; Pyczak, Florian

    2015-01-01

    Highlights: • The sintering of the MIM Ti–Nb alloy consists of three steps. • The Nb particles act as diffusion barriers during sintering. • The TiC x only precipitate in the cooling step during sintering. • The TiC x hardly influence the sintering process of MIM Ti–Nb alloy. • The MIM Ti–Nb alloy exhibits high strength, low Young’s modulus but poor ductility. - Abstract: Sintering behavior, microstructure and mechanical properties of a Ti–16Nb alloy processed by metal injection molding (MIM) technology using elemental powders were investigated in this work by optical microscopy, X-ray diffraction (XRD), dilatometer, scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). It was found that from 700 °C to 1500 °C the homogenization and densification process of MIM Ti–16Nb alloy consisted of three steps, i.e., Ti-diffusion-controlled step, Ti–Nb-diffusion step and matrix-diffusion step. Titanium carbide formation was observed in the samples sintered at 1300 °C and 1500 °C, but not in the ones sintered at 900 °C and 1100 °C. The MIM Ti–16Nb specimens sintered at 1500 °C exhibited a good combination of high tensile strength and low Young’s modulus. However, the titanium carbide particles led to poor ductility

  17. Reversed austenite for enhancing ductility of martensitic stainless steel

    Science.gov (United States)

    Dieck, S.; Rosemann, P.; Kromm, A.; Halle, T.

    2017-03-01

    The novel heat treatment concept, “quenching and partitioning” (Q&P) has been developed for high strength steels with enhanced formability. This heat treatment involves quenching of austenite to a temperature between martensite start and finish, to receive a several amount of retained austenite. During the subsequent annealing treatment, the so called partitioning, the retained austenite is stabilized due to carbon diffusion, which results in enhanced formability and strength regarding strain induced austenite to martensite transformation. In this study a Q&P heat treatment was applied to a Fe-0.45C-0.65Mn-0.34Si-13.95Cr stainless martensite. Thereby the initial quench end temperature and the partitioning time were varied to characterize their influence on microstructural evolution. The microstructural changes were analysed by dilatometer measurements, X-ray diffraction and scanning electron microscopy, including electron back-scatter diffraction. Compression testing was made to examine the mechanical behaviour. It was found that an increasing partitioning time up to 30 min leads to an enhanced formability without loss in strength due to a higher amount of stabilized retained and reversed austenite as well as precipitation hardening.

  18. Deformability Parameters of Varved Clays From the Iłów (Central Poland Area Based on the Selected Field Tests

    Directory of Open Access Journals (Sweden)

    Zawrzykraj Piotr Zbigniew

    2017-03-01

    Full Text Available This publication presents the results of research carried out for the ice-dammed clays of the Iłów region, formed during Vistula glaciation. Pressuremeter tests, dilatometer tests and static probes were made. The tests were performed on the study site in Piskorzec near Iłów. In this region, ice-dammed clays are present almost from the land surface reaching the thickness of about 11 m. This site is the westernmost experimental site of clays of the “Warsaw Ice-Dammed Lake” among those presented in the literature. Research and their analysis showed differences in deformability due to the test procedure in connection with the structure of varved clays. Pressuremeter test, even though it is the most time consuming and challenging among the tests performed, allows the most complete characteristics of deformability of varved clays to be obtained. Vertical profile of clays being studied appears to be fairly homogeneous in terms of mechanical properties. Nevertheless, some parts of the profile clearly differ from the average values. This indicates the rate of post sedimentary changes varied in different parts of research profile. The data obtained are consistent with the values for ice-dammed clays from Radzymin and Sochaczew areas. Comparison of the engineering properties of varved clays to other experimental sites points to their similar geological history. It confirms that the experimental sites belong to one ice-dammed lake covering the areas of the Warsaw Basin.

  19. Rock stresses (Grimsel rock laboratory)

    International Nuclear Information System (INIS)

    Pahl, A.; Heusermann, S.; Braeuer, V.; Gloeggler, W.

    1989-01-01

    On the research and development project 'Rock Stress Measurements' the BGR has developed and tested several test devices and methods at GTS for use in boreholes at a depth of 200 m and has carried out rock mechanical and engineering geological investigations for the evaluation and interpretation of the stress measurements. The first time a computer for data processing was installed in the borehole together with the BGR-probe. Laboratory tests on hollow cylinders were made to study the stress-deformation behavior. To validate and to interprete the measurement results some test methods were modelled using the finite-element method. The dilatometer-tests yielded high values of Young's modulus, whereas laboratory tests showed lower values with a distinct deformation anisotropy. Stress measurements with the BGR-probe yielded horizontal stresses being higher than the theoretical overburden pressure and vertical stresses which agree well with the theoretical overburden pressure. These results are comparable to the results of the hydraulic fracturing tests, whereas stresses obtained with CSIR-triaxial cells are generally lower. The detailed geological mapping of the borehole indicated relationships between stress and geology. With regard to borehole depth different zones of rock structure joint frequency, joint orientation, and orientation of microfissures as well as stress magnitude, stress direction, and degree of deformation anisotropy could be distinguished. (orig./HP) [de

  20. Modeling of Non-isothermal Austenite Formation in Spring Steel

    Science.gov (United States)

    Huang, He; Wang, Baoyu; Tang, Xuefeng; Li, Junling

    2017-12-01

    The austenitization kinetics description of spring steel 60Si2CrA plays an important role in providing guidelines for industrial production. The dilatometric curves of 60Si2CrA steel were measured using a dilatometer DIL805A at heating rates of 0.3 K to 50 K/s (0.3 °C/s to 50 °C/s). Based on the dilatometric curves, a unified kinetics model using the internal state variable (ISV) method was derived to describe the non-isothermal austenitization kinetics of 60Si2CrA, and the abovementioned model models the incubation and transition periods. The material constants in the model were determined using a genetic algorithm-based optimization technique. Additionally, good agreement between predicted and experimental volume fractions of transformed austenite was obtained, indicating that the model is effective for describing the austenitization kinetics of 60Si2CrA steel. Compared with other modeling methods of austenitization kinetics, this model, which uses the ISV method, has some advantages, such as a simple formula and explicit physics meaning, and can be probably used in engineering practice.

  1. Thermal expansion of ceramic samples containing natural zeolite

    Science.gov (United States)

    Sunitrová, Ivana; Trník, Anton

    2017-07-01

    In this study the thermal expansion of ceramic samples made from natural zeolite is investigated. Samples are prepared from the two most commonly used materials in ceramic industry (kaolin and illite). The first material is Sedlec kaolin from Czech Republic, which contains more than 90 mass% of mineral kaolinite. The second one is an illitic clay from Tokaj area in Hungary, which contains about 80 mass% of mineral illite. Varying amount of the clay (0 % - 50 %) by a natural zeolite from Nižný Hrabovec (Slovak Republic), containing clinoptilolite as major mineral phase is replaced. The measurements are performed on cylindrical samples with a diameter 14 mm and a length about 35 mm by a horizontal push - rod dilatometer. Samples made from pure kaolin, illite and zeolite are also subjected to this analysis. The temperature regime consists from linear heating rate of 5 °C/min from 30 °C to 1100 °C. The results show that the relative shrinkage of ceramic samples increases with amount of zeolite in samples.

  2. Development of a Standard Methodology for the Quantitative Measurement of Steel Phase Transformation Kinetics and Dilation Strains Using Dilatometric Methods, QMST (TRP 0015)

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Manish Metha; Dr. Tom Oakwood

    2004-04-28

    The purpose of this collaborative project was to develop a standard practice for obtaining and archiving quantitative steel transformation kinetic data and thermal strain data. Two families of dilatometric equipment were employed to develop this standard practice for testing bar product steels. These include high-speed quenching and deformation dilatometers and Gleeble{reg_sign} thermomechanical simulation instruments. Standard measurement, data interpretation and data reporting methods were developed and defined by the cross-industry QMST Consortium members consisting of steel-manufacturers, forgers, heat-treaters, modelers, automotive and heavy vehicle OEMs along with team expert technologists from the National Labs and academia. The team designed phase transformation experiments on two selected steel grades to validate the standard practices--a medium carbon grade SAE 1050 and an alloy steel SAE 8620. A final standard practice document was developed based on the two dilatometry methods, and was submitted to and approved by ASTM (available as A1033-04). The standard practice specifies a method for measuring austenite transformation under no elastic stress or plastic deformation. These methods will be an enabler for the development and electronic archiving of a quantitative database for process modeling using computer simulation software, and will greatly assist endusers in developing accurate process and product simulations during the thermo-mechanical processing of bar and rod product steels.

  3. Microstructure based procedure for process parameter control in rolling of aluminum thin foils

    Science.gov (United States)

    Johannes, Kronsteiner; Kabliman, Evgeniya; Klimek, Philipp-Christoph

    2018-05-01

    In present work, a microstructure based procedure is used for a numerical prediction of strength properties for Al-Mg-Sc thin foils during a hot rolling process. For this purpose, the following techniques were developed and implemented. At first, a toolkit for a numerical analysis of experimental stress-strain curves obtained during a hot compression testing by a deformation dilatometer was developed. The implemented techniques allow for the correction of a temperature increase in samples due to adiabatic heating and for the determination of a yield strength needed for the separation of the elastic and plastic deformation regimes during numerical simulation of multi-pass hot rolling. At the next step, an asymmetric Hot Rolling Simulator (adjustable table inlet/outlet height as well as separate roll infeed) was developed in order to match the exact processing conditions of a semi-industrial rolling procedure. At each element of a finite element mesh the total strength is calculated by in-house Flow Stress Model based on evolution of mean dislocation density. The strength values obtained by numerical modelling were found in a reasonable agreement with results of tensile tests for thin Al-Mg-Sc foils. Thus, the proposed simulation procedure might allow to optimize the processing parameters with respect to the microstructure development.

  4. The intrinsic thermal expansion of point defects in Al

    International Nuclear Information System (INIS)

    Asty, Michel.

    1975-11-01

    The differential length measurement between two specimens, on pure and the other containing point defects, leads to the intrinsic thermal coefficient of expansion β(d) of the defect. A differential dilatometer by Laser interferometry is described operating between 77 and 300 K, with a sensitivity of about 100A on the length difference between an alloy sample and a pure dummy. Concerning substitutional impurities in aluminium between -190 deg C and -90 deg C, the intrinsic thermal coefficient of expansion of the defect β(d) is shown to have an absolute value much larger than the thermal expansion coefficient β 0 of the aluminium matrix: β(d)/β 0 =+3 to +6 for the magnesium impurity, β(d)/β 0 =-3 to -4 for the calcium impurity, and to be independent of the temperature. The existing theoretical models give evaluations for away from modeles theoriques existant sont tres loin d'expliquer les resultats experimentaux. high temperature, the results show that vacancies and divacancies, before collapsing in dislocation loops, form multivacancy clusters with large formation volumes: such a property makes these clusters comparable to cavities where the formation volume per vacancy is equal to the atomic volume of the matrix [fr

  5. Investigation of the sinterability of ZrO{sub 2} (Y{sub 2}O3{sub )}-bioglass dental ceramics by dilatometry; Estudo da sinterabilidade de ceramicas dentarias de ZrO{sub 2} (Y{sub 2}O3{sub )}-biovidro usando dilatometria

    Energy Technology Data Exchange (ETDEWEB)

    Bicalho, Luiz de Araujo; Barboza, Miguel Ribeiro Justino [Universidade de Sao Paulo (USP), Lorena, SP (Brazil). Escola de Engenharia; Strecker, Kurt [Universidade Federal de Sao Joao del Rei (UFSJ), MG (Brazil); Santos, Claudinei dos; Habibe, Alexandre Fernandes; Magnago, Roberto de Oliveira [Centro Universitario de Volta Redonda (UNIFOA), Volta Redonda, RJ (Brazil)

    2013-06-15

    The objective of this work is to study by dilatometry, the liquid phase sintering of ZrO{sub 2} ceramics using bioglass as sintering additive. Y{sub 2} O{sub 3} - stabilized ZrO{sub 2} powders were mixed with 3, 5 and 10 wt% of bioglass with the composition based on 3CaOP{sub 2} O{sub 5} -MgO-SiO{sub 2} system. Specimens were prepared by cold uniaxial pressing under 80MPa and the green relative density was determined. The sintering behavior was studied by measuring the linear shrinkage of samples in a dilatometer in relation to the temperature. The heating and cooling rates used in this study were 10 deg C/min and the maximum sintering temperatures was 1300 deg C with a 120 min isothermal holding time. The results of the shrinkage and shrinkage rates in regard of the sintering temperature and time were related to the amount of bioglass added. The sintered samples were characterized by X-ray diffraction analysis and their relative density. SEM micrographs indicates similar microstructure, and an increase of bioglass content leads to increasing of monoclinic ZrO{sub 2} phase content. The dilatometry results indicate a reduction of the temperature where a maximum shrinkage rate occurs, as function of bioglass increasing. Furthermore, the use of liquid phase reduces the maximum sintering temperature of 1447 deg C to 1250-1280 deg C. (author)

  6. Thermal expansion of fibre-reinforced composites

    International Nuclear Information System (INIS)

    Schneider, B.

    1991-07-01

    The integral thermal expansion and the coefficient of thermal expansion (CTE) of carbon and Kevlar fibre-reinforced composites were measured with high accuracy from 5 K to room temperature. For this, a laser dilatometer and a sophisticated measuring procedure were used. CTE dependence on the orientation angle ω of angle-ply laminates was determined for samples with 5 different fibre alignments (UD 0deg, +/-30deg, +/-45deg, +/-60deg and UD 90deg). A high variability of the CTE with the orientation angle was shown. At angles of approximately +/-30deg even negative CTEs were found. With suitable reinforcing fibres being selected, their absolute values rose up to 30-100% of the positive CTEs of metals. Hence, composites of this type would be suitable as compensating materials in metal constructions where little thermal expansion is desired. To check the lamination theory, theoretical computations of the CTE- ω -dependence were compared with the measured values. An excellent agreement was found. Using the lamination theory, predictions about the expansion behaviour of angle-ply laminates can be made now, if the thermal and mechanical properties of the unidirectional (UD) laminate are known. Furthermore, it is possible to carry out simulation computations aimed at investigating the influence of a single parameter of the UD-laminate (e.g. shear modulus) on the expansion of the angle-ply laminate. (orig.) [de

  7. Numerical evaluation of ABS parts fabricated by fused deposition modeling and vapor smoothing

    Directory of Open Access Journals (Sweden)

    Sung-Uk Zhang

    2017-12-01

    Full Text Available The automotive industry has focused to use polymer materials in order to increase energy efficiency. So, the industry pays attention to use 3D printing technologies using several polymers. Among several 3D printer technologies, fused deposition modeling (FDM is one of the popular 3D printing technologies due to an inexpensive extrusion machine and multi-material printing. FDM could use thermoplastics such as ABS, PLA, ULTEM so on. However, it has a problem related to the post-processing because FDM has relatively poor layer resolution. In this study, the mechanical properties of ABS parts fabricated by FDM were measured. The ABS parts were divided into one with vapor smoothing process and the other without the vapor smoothing process which is one of the post-processing methods. Using dynamic mechanical analysis (DMA and dilatometer, temperature-dependent storage modulus and CTE for ABS specimens were measured. Based on the measured thermo-mechanical properties of ABS parts, finite element analysis was performed for an automotive bumper made of ABS. Moreover, response surface methodology was applied to study relationships among design parameters of thickness of the bumper, ambient temperature, and application of the vapor smoothing process. In result, a design guideline for a ABS product could be provided without time-consuming experiments

  8. Fabrication and Thermophysical Properties of La(2-x)Zr(2-y)O7 Nanocrystal by a Sol-Gel Method.

    Science.gov (United States)

    Li, Hui; Che, Ping; Zhao, Ziqiang; Liu, Shixiang; Li, Wenjun

    2016-03-01

    Non-Stoichiometric La2Zr2O7 (La(2-x)Zr(2-y)O7) Nanocrystal was synthesized by a simple sol-gel method. The crystalline structure, oxygen vacancy concentration, thermal expansion coefficient, as well as the fracture toughness of as-prepared materials were charactered by XRD, TG-DSC, PL spectra, dilatometer, and electronic universal testing machine respectively. The crystal structure of La2Zr2O7 is of the cubic type while lattice parameter increases with the deviatation of Zr4+ and La3+ from Stoichiometric La2Zr2O7 increasing. The average linear thermal expansion coefficient of non-stoichiometric La2Zr2O7 is obviously bigger than that of La2Zr2O7 in the temperature range between 150 degrees C and 950 degrees C. The fracture toughness of La(2-x)Zr(2-y)O7 increases with x and y increasing up to x = 0.3 and y = 0.25.

  9. Temperature dependence of the volumetric properties of some alkoxypropanols + n-alkanol mixtures

    International Nuclear Information System (INIS)

    Pal, Amalendu; Kumar, Harsh

    2004-01-01

    The excess molar volumes V m E for binary liquid mixtures containing dipropylene glycol monomethyl ether or dipropylene glycol monobutyl ether and methanol, 1-propanol, 1-pentanol and 1-heptanol have been measured as a function of composition using a continuous dilution dilatometer at T=(288.15, 298.15, and 308.15) K and atmospheric pressure over the whole concentration range. The excess volume results allowed the following mixing quantities to be reported in all range of concentrations or at equimolar concentrations: α, volume expansivity; (∂V m E /∂T) p ; (∂H E /∂P) T at T=298.15 K. The obtained results have been compared at T=298.15 K with the calculated values by using the Flory theory of liquid mixtures. The theory predicts the α, and α E values rather well, while the calculated values of (∂V m E /∂T) p and (∂H E /∂P) T show general variation with the alkyl chain length of the alkoxypropanols. The results are discussed in terms of order or disorder creation

  10. Softening of the elastic shear mode C{sub 66} in iron-based superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Boehmer, Anna; Burger, Philipp [Karlsruher Institut fuer Technologie, Institut fuer Festkoerperphysik, D-76021 Karlsruhe (Germany); Karlsruher Institut fuer Technologie, Fakultaet fuer Physik, D-76128 Karlsruhe (Germany); Hardy, Frederic; Schweiss, Peter; Fromknecht, Rainer; Wolf, Thomas; Meingast, Christoph [Karlsruher Institut fuer Technologie, Institut fuer Festkoerperphysik, D-76021 Karlsruhe (Germany); Reinecker, Marius; Schranz, Wilfried [Universitaet Wien, Fakultaet fuer Physik, A-1090 Wien, Vienna (Austria)

    2013-07-01

    The structural phase transition of underdoped iron-based superconductors is accompanied by a large softening of the elastic shear mode C{sub 66}, which has attracted considerable attention. This softening has been discussed both in terms of orbital and spin-nematic fluctuations which would be responsible for the structural phase transition and, possibly, superconductivity. However, sample requirements have so far restricted experimental investigations of C{sub 66} (via measurements of the ultrasound velocity) to the Ba(Fe,Co){sub 2}As{sub 2} system. Here, we report on a new technique, based on a three-point bending setup, to probe the Young's modulus of a sample with a capacitance dilatometer. For certain orientations, the Young's modulus is related to the elastic constant C{sub 66} whose effective temperature dependence can be obtained. Platelet-like samples, as frequently encountered for iron-based systems, are easily studied with our setup. Data on several systems are presented and discussed.

  11. Characterization and densification studies on ThO{sub 2}-UO{sub 2} pellets derived from ThO{sub 2} and U{sub 3}O{sub 8} powders

    Energy Technology Data Exchange (ETDEWEB)

    Kutty, T.R.G. [Radiometallurgy Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)]. E-mail: tkutty@magnum.barc.ernet.in; Hegde, P.V. [Radiometallurgy Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Khan, K.B. [Radiometallurgy Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Jarvis, T. [Radiometallurgy Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Sengupta, A.K. [Radiometallurgy Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Majumdar, S. [Radiometallurgy Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Kamath, H.S. [Nuclear Fuels Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

    2004-12-01

    ThO{sub 2} containing around 2-3% {sup 233}UO{sub 2} is the proposed fuel for the forthcoming Indian Advanced Heavy Water Reactor (AHWR). This fuel is prepared by powder metallurgy technique using ThO{sub 2} and U{sub 3}O{sub 8} powders as the starting material. The densification behaviour of the fuel was evaluated using a high temperature dilatometer in four different atmospheres Ar, Ar-8%H{sub 2}, CO{sub 2} and air. Air was found to be the best medium for sintering among them. For Ar and Ar-8%H{sub 2} atmospheres, the former gave a slightly higher densification. Thermogravimetric studies carried out on ThO{sub 2}-2%U{sub 3}O{sub 8} granules in air showed a continuous decrease in weight up to 1500 deg. C. The effectiveness of U{sub 3}O{sub 8} in enhancing the sintering of ThO{sub 2} has been established.

  12. GENERAL EARTHQUAKE-OBSERVATION SYSTEM (GEOS).

    Science.gov (United States)

    Borcherdt, R.D.; Fletcher, Joe B.; Jensen, E.G.; Maxwell, G.L.; VanSchaack, J.R.; Warrick, R.E.; Cranswick, E.; Johnston, M.J.S.; McClearn, R.

    1985-01-01

    Microprocessor technology has permitted the development of a General Earthquake-Observation System (GEOS) useful for most seismic applications. Central-processing-unit control via robust software of system functions that are isolated on hardware modules permits field adaptability of the system to a wide variety of active and passive seismic experiments and straightforward modification for incorporation of improvements in technology. Various laboratory tests and numerous deployments of a set of the systems in the field have confirmed design goals, including: wide linear dynamic range (16 bit/96 dB); broad bandwidth (36 hr to 600 Hz; greater than 36 hr available); selectable sensor-type (accelerometer, seismometer, dilatometer); selectable channels (1 to 6); selectable record mode (continuous, preset, trigger); large data capacity (1. 4 to 60 Mbytes); selectable time standard (WWVB, master, manual); automatic self-calibration; simple field operation; full capability to adapt system in the field to a wide variety of experiments; low power; portability; and modest costs. System design goals for a microcomputer-controlled system with modular software and hardware components as implemented on the GEOS are presented. The systems have been deployed for 15 experiments, including: studies of near-source strong motion; high-frequency microearthquakes; crustal structure; down-hole wave propagation; teleseismicity; and earth-tidal strains.

  13. Extension of the master sintering curve for constant heating rate modeling

    Science.gov (United States)

    McCoy, Tammy Michelle

    The purpose of this work is to extend the functionality of the Master Sintering Curve (MSC) such that it can be used as a practical tool for predicting sintering schemes that combine both a constant heating rate and an isothermal hold. Rather than just being able to predict a final density for the object of interest, the extension to the MSC will actually be able to model a sintering run from start to finish. Because the Johnson model does not incorporate this capability, the work presented is an extension of what has already been shown in literature to be a valuable resource in many sintering situations. A predicted sintering curve that incorporates a combination of constant heating rate and an isothermal hold is more indicative of what is found in real-life sintering operations. This research offers the possibility of predicting the sintering schedule for a material, thereby having advanced information about the extent of sintering, the time schedule for sintering, and the sintering temperature with a high degree of accuracy and repeatability. The research conducted in this thesis focuses on the development of a working model for predicting the sintering schedules of several stabilized zirconia powders having the compositions YSZ (HSY8), 10Sc1CeSZ, 10Sc1YSZ, and 11ScSZ1A. The compositions of the four powders are first verified using x-ray diffraction (XRD) and the particle size and surface area are verified using a particle size analyzer and BET analysis, respectively. The sintering studies were conducted on powder compacts using a double pushrod dilatometer. Density measurements are obtained both geometrically and using the Archimedes method. Each of the four powders is pressed into ¼" diameter pellets using a manual press with no additives, such as a binder or lubricant. Using a double push-rod dilatometer, shrinkage data for the pellets is obtained over several different heating rates. The shrinkage data is then converted to reflect the change in relative

  14. Studies on thermal reactions and sintering behaviour of red clays by irreversible dilatometry

    Science.gov (United States)

    Anil, Asha; Misra, S. N.; Misra, N. M.

    2018-05-01

    Thermal behavior of clays strongly influences that of ceramic bodies made thereof and hence, its study is must for assessing its utility in ceramic products as well as to set the body composition. Irreversible dilatometry is an effective thermal analysis tool for evaluating thermal reactions as well as sintering behavior of clays or clay based ceramic bodies. In this study, irreversible dilatometry of four red clay samples (S, M, R and G) of Gujarat region, which vary in their chemical and mineralogical compositions was carried out using a Dilatometer and compared. Chemical analysis and XRD of red clays were carried out. XRD showed that major clay minerals in S, M and R clays are kaolinite. However, clay marked R and G showed presence of both kaolinite and illite and /muscovite. Presence of non-clay minerals such as hematite, quartz, anatase were also observed in all clays. XRD results were in agreement with chemical analyses results. Rational analyses showed variation in amount of clay and non-clay minerals in red clay samples. Evaluation of dilatometric curves showed that clay marked as S, M and R exhibit patterns typical for kaolinitic clays. Variation in linear expansion (up to 550°C) and shrinkage (above 550°C) between these three clays was found to be related to difference in amount of quartz and kaolinite respectively. However, dilatometric curve of G exhibit a pattern similar to that for an illitic clay. This study confirmed that sintering of investigated kaolinitic and illitic and / muscovitic red clays initiates at above 1060°C and 860°C respectively and this behaviour strongly depends upon type and amount of minerals and their chemical compositions.

  15. An assessment of the contributing factors to the nanoscale structural refinement of advanced bainitic steels

    International Nuclear Information System (INIS)

    Cornide, J.; Garcia-Mateo, C.; Capdevila, C.; Caballero, F.G.

    2013-01-01

    A new generation of steels has been designed, which on transformation at low temperature (200–350 °C), leads to a nano-scale microstructure, known as NANOBAIN. The microstructure consists of slender crystals of ferrite, whose controlling scale compares well with that of carbon nanotubes (20–40 nm). These advanced steels present the highest strength/toughness combinations ever recorded in bainitic steels. Their properties are mainly a consequence of the formation of nanoscale bainitic ferrite plates at very low temperatures. Transmission electron microscopy observations have shown that plastic relaxation in the austenite adjacent to the bainite plates may control the final size of the bainitic ferrite plates. The dislocation debris generated in this process resists the advance of the bainitic ferrite–austenite interface, the resistance being greatest for strong austenite. The yield strength of the austenite must then feature in any assessment of plate size. In this scenario, the plates are expected to become thicker at high temperatures because the yield strength of the austenite will then be lower. The goal of this study is to evaluate the influence of yield strength of austenite to the nanoscale structural refinement of advanced bainitic steels. In this sense, in situ measurements of austenite strength before bainite formation using a deformation dilatometer Bähr 805D have been performed in a medium carbon high silicon steel transforming at intermediate temperatures (325–400 °C) to a submicron structure of bainite and in a high carbon high silicon steel transforming at low temperatures (200–350 °C) to nanostructured bainite. The role of the transformation driving force on the bainite plate thickness will be also discussed

  16. An assessment of the contributing factors to the nanoscale structural refinement of advanced bainitic steels

    Energy Technology Data Exchange (ETDEWEB)

    Cornide, J., E-mail: jca@cenim.csic.es [Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC), Avda Gregorio del Amo 8, Madrid E-28040 (Spain); Garcia-Mateo, C., E-mail: cgm@cenim.csic.es [Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC), Avda Gregorio del Amo 8, Madrid E-28040 (Spain); Capdevila, C., E-mail: ccm@cenim.csic.es [Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC), Avda Gregorio del Amo 8, Madrid E-28040 (Spain); Caballero, F.G., E-mail: fgc@cenim.csic.es [Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC), Avda Gregorio del Amo 8, Madrid E-28040 (Spain)

    2013-11-15

    A new generation of steels has been designed, which on transformation at low temperature (200–350 °C), leads to a nano-scale microstructure, known as NANOBAIN. The microstructure consists of slender crystals of ferrite, whose controlling scale compares well with that of carbon nanotubes (20–40 nm). These advanced steels present the highest strength/toughness combinations ever recorded in bainitic steels. Their properties are mainly a consequence of the formation of nanoscale bainitic ferrite plates at very low temperatures. Transmission electron microscopy observations have shown that plastic relaxation in the austenite adjacent to the bainite plates may control the final size of the bainitic ferrite plates. The dislocation debris generated in this process resists the advance of the bainitic ferrite–austenite interface, the resistance being greatest for strong austenite. The yield strength of the austenite must then feature in any assessment of plate size. In this scenario, the plates are expected to become thicker at high temperatures because the yield strength of the austenite will then be lower. The goal of this study is to evaluate the influence of yield strength of austenite to the nanoscale structural refinement of advanced bainitic steels. In this sense, in situ measurements of austenite strength before bainite formation using a deformation dilatometer Bähr 805D have been performed in a medium carbon high silicon steel transforming at intermediate temperatures (325–400 °C) to a submicron structure of bainite and in a high carbon high silicon steel transforming at low temperatures (200–350 °C) to nanostructured bainite. The role of the transformation driving force on the bainite plate thickness will be also discussed.

  17. Influence of hot plastic deformation and cooling rate on martensite and bainite start temperatures in 22MnB5 steel

    Energy Technology Data Exchange (ETDEWEB)

    Nikravesh, M., E-mail: nikravesh@yahoo.com [Department of Material Science and Engineering, Shahid Bahonar University, Kerman (Iran, Islamic Republic of); Naderi, M. [Department of Mining and Metallurgy, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Akbari, G.H. [Department of Material Science and Engineering, Shahid Bahonar University, Kerman (Iran, Islamic Republic of)

    2012-04-01

    Highlights: Black-Right-Pointing-Pointer Reduction of cooling rate, can cause to increase or decrease M{sub s} and M{sub f}. Black-Right-Pointing-Pointer 40% hot plastic deformation hindered the martensitic transformation. Black-Right-Pointing-Pointer Hot plastic deformation, caused to decrease M{sub f} and M{sub s}, while B{sub s} increased. Black-Right-Pointing-Pointer The critical cooling rate increased 40 Degree-Sign C/s due to apply 40% hot deformation. - Abstract: During hot stamping process, hot forming, cooling and phase transformations are performed in a single step. As a matter of fact, multifunctional phenomena happen and affect each other. Among these phenomena, martensitic and bainitic transformations have the greatest importance. In the current research, the start temperatures of martensite and bainite of 22MnB5 boron steel have been measured in undeformed and 40% deformed conditions, and in various cooling rates from 0.4 Degree-Sign C/s to 100 Degree-Sign C/s by means of deformation dilatometer. It is concluded that, reduction of cooling rate, could bring about an increase or decrease in M{sub s} and M{sub f}, depending on other phases formation before martensite. Also, hot plastic deformation, hindered the martensitic transformation and decreased M{sub f} and M{sub s} especially at lower cooling rates, while B{sub s} increased. Furthermore, the critical cooling rate, increased about 40 Degree-Sign C/s by applying 40% hot plastic deformation.

  18. Viability of Pushrod Dilatometry Techniques for High Temperature In-Pile Measurements

    Energy Technology Data Exchange (ETDEWEB)

    J. E. Daw; J. L. Rempe; D. L. Knudson; K. G. Condie; J. C. Crepeau

    2008-03-01

    To evaluate the performance of new fuel, cladding, and structural materials for use in advanced and existing nuclear reactors, robust instrumentation is needed. Changes in material deformation are typically evaluated out-of-pile, where properties of materials are measured after samples were irradiated for a specified length of time. To address this problem, a series of tests were performed to examine the viability of using pushrod dilatometer techniques for in-pile instrumentation to measure deformation. The tests were performed in three phases. First, familiarity was gained in the use and accuracy of this system by testing samples with well defined thermal elongation characteristics. Second, high temperature data for steels, specifically SA533 Grade B, Class 1 (SA533B1) Low Alloy Steel and Stainless Steel 304 (SS304), found in Light Water Reactor (LWR) vessels, were aquired. Finally, data were obtained from a short pushrod in a horizontal geometry to data obtained from a longer pushrod in a vertical geometry, the configuration likely to be used for in-situ measurements. Results of testing show that previously accepted data for the structural steels tested, SA533B1 and SS304, are inaccurate at high temperatures (above 500 oC) due to extrpolation of high temperature data. This is especially true for SA533B1, as previous data do not account for the phase transformation of the material between 730 oC and 830 oC. Also, comparison of results for horizontal and vertical configurations show a maximum percent difference of 2.02% for high temperature data.

  19. Effect of temperature on the expansion and microstructure Of U3 Si2-AI mini plate fuel of 3.6 g/cm3 uranium loading

    International Nuclear Information System (INIS)

    Ginting, A. Br.; Samosir, N.; Suparjo; Nasution, H.

    2000-01-01

    Expansion analysis has been conducted to 50 x 20-mm U 3 Si 2 -AI mini plate of 3.6 g/cm 3 uranium loading using dilatometer. The analysis was carried out at various temperatures of 170 o C, 350 o C and 550 o C in Argon medium with delay time 4 days. The result showed that the fuel plate was relatively stable with increasing of heating time but underwent significant expansion. Heating at 170 o C, 350 o C and 550 o C resulted in the expansion of the U 3 Si 2 -AI fuel plate of to 83-212 mum, 333-475 mum, and 433-724 mum with coefficient expansion of 24.2x10 -6 / o C - 24.3x10 -6 / o C, 25.5x10 -6 / o C - 26.2x10 -6 /'oC and 26.6 x 10 -6 / o C - 28.2 x 10 -6 / o C respectively. Microanalysis of the U 3 Si 2 -AI mini plate fuel with SEM-EDS upon heating at those temperature variation showed that microstructure change didn't occur at 170 o C, mean while interaction between AIMg2 cladding and the fuel meat appeared to take place at 350 o C and 550 o C. Data on the expansion and microstructure change of U 3 Si 2 -AI fuel plate upon heating are of great important for the manufacture/fabrication of research fuel plate to produce silicide fuel element for higher uranium loading. (author)

  20. Effects of tungsten on continuous cooling transformation characteristics of microalloyed steels

    International Nuclear Information System (INIS)

    Zhao, Jingwei; Jiang, Zhengyi; Kim, Ji Soo; Lee, Chong Soo

    2013-01-01

    Highlights: ► W has a positive effect on refining the austenite grains and precipitates. ► W shifts the ranges of transformation products to the right side of CCT diagram. ► W addition induces increased austenitisation starting and finishing temperatures. ► The critical cooling rate for phase transformation is decreased after W addition. - Abstract: Continuous cooling transformation (CCT) characteristics of microalloyed steels with different tungsten (W) contents (0, 0.1 and 1 wt.%) were investigated to obtain the necessary information for heat treatment of these steels. The effects of W addition on the sizes of prior austenite grains and precipitates were analysed. CCT diagrams were obtained by varying the cooling rates from 0.1 to 120 °C/s. Transformation characteristics were determined by using dilatometer test, microscopic observation and hardness measurement. The results showed that W had a positive effect on the refinement of prior austenite grains and precipitates. The CCT diagrams exhibited that the ranges of transformation products were shifted to the right side of the diagram when the W content increased. CCT diagram for steel with 0.1% W was similar in shape to that without W. The addition of 1% W induced two separated transformation ranges in the cooling rate range of 0.1 to 1 °C/s in the diagram. Both the austenitisation starting and finishing temperatures were raised as W was added. W addition induced decreased critical cooling rates for phase transformations and obtaining complete ferrite + pearlite microstructures. The martensite transformation temperature was decreased after W addition. The addition of W caused increased hardness, and the hardness obeyed an exponential type relationship with cooling rate

  1. Volcano geodesy: The search for magma reservoirs and the formation of eruptive vents

    Science.gov (United States)

    Dvorak, J.J.; Dzurisin, D.

    1997-01-01

    Routine geodetic measurements are made at only a few dozen of the world's 600 or so active volcanoes, even though these measurements have proven to be a reliable precursor of eruptions. The pattern and rate of surface displacement reveal the depth and rate of pressure increase within shallow magma reservoirs. This process has been demonstrated clearly at Kilauea and Mauna Loa, Hawaii; Long Valley caldera, California; Campi Flegrei caldera, Italy; Rabaul caldera, Papua New Guinea; and Aira caldera and nearby Sakurajima, Japan. Slower and lesser amounts of surface displacement at Yellowstone caldera, Wyoming, are attributed to changes in a hydrothermal system that overlies a crustal magma body. The vertical and horizontal dimensions of eruptive fissures, as well as the amount of widening, have been determined at Kilauea, Hawaii; Etna, Italy; Tolbachik, Kamchatka; Krafla, Iceland; and Asal-Ghoubbet, Djibouti, the last a segment of the East Africa Rift Zone. Continuously recording instruments, such as tiltmeters, extensometers, and dilatometers, have recorded horizontal and upward growth of eruptive fissures, which grew at rates of hundreds of meters per hour, at Kilauea; Izu-Oshima, Japan; Teishi Knoll seamount, Japan; and Piton de la Fournaise, Re??union Island. In addition, such instruments have recorded the hour or less of slight ground movement that preceded small explosive eruptions at Sakurajima and presumed sudden gas emissions at Galeras, Colombia. The use of satellite geodesy, in particular the Global Positioning System, offers the possibility of revealing changes in surface strain both local to a volcano and over a broad region that includes the volcano.

  2. Picometre and nanoradian heterodyne interferometry and its application in dilatometry and surface metrology

    International Nuclear Information System (INIS)

    Schuldt, T; Kögel, H; Spannagel, R; Braxmaier, C; Gohlke, M; Peters, A; Johann, U; Weise, D

    2012-01-01

    A high-sensitivity heterodyne interferometer implementing differential wavefront sensing for tilt measurement was developed over the last few years. With this setup, using an aluminium breadboard and compact optical mounts with a beam height of 2 cm, noise levels less than 5 pm Hz −1/2 in translation and less than 10 nrad Hz −1/2 in tilt measurement, both for frequencies above 10 −2 Hz, have been demonstrated. Here, a new, compact and ruggedized interferometer setup utilizing a baseplate made of Zerodur, a thermally and mechanically highly stable glass ceramic with a coefficient of thermal expansion (CTE) of 2 × 10 −8 K −1 , is presented. The optical components are fixed to the baseplate using a specifically developed, easy-to-handle, assembly-integration technology based on a space-qualified two-component epoxy. While developed as a prototype for future applications aboard satellite space missions (such as Laser Interferometer Space Antenna), the interferometer is used in laboratory experiments for dilatometry and surface metrology. A first dilatometer setup with a demonstrated accuracy of 10 −7 K −1 in CTE measurement was realized. As it was seen that the accuracy is limited by the dimensional stability of the sample tube support, a new setup was developed utilizing Zerodur as structural material for the sample tube support. In another activity, the interferometer is used for characterization of high-quality mirror surfaces at the picometre level and for high-accuracy two-dimensional surface characterization in a prototype for industrial applications. In this paper, the corresponding designs, their realizations and first measurements of both applications in dilatometry and surface metrology are presented

  3. Effect of ZrO2 on the sintering behavior, strength and high-frequency dielectric properties of electrical ceramic porcelain insulator

    Science.gov (United States)

    Singh Mehta, Niraj; Sahu, Praveen Kumar; Ershad, Md; Saxena, Vipul; Pyare, Ram; Ranjan Majhi, Manas

    2018-01-01

    In the present study, the effect of ZrO2 on the sintering, strength and dielectric behavior of electrical ceramic porcelain insulator with substituting alumina content by zirconia (in weight percentage from 0% to 30%) is investigated. The different composition of samples containing different zirconia (ZrO2) contents of 0, 10, 20, and 30 wt% are prepared using the uniaxial pressure technique applying 160 MPa pressure. Further, the prepared samples are also analyzed for sintering temperatures (1350 °C), and effects are observed on mechanical and electric properties of porcelain insulator. Different characterizations such as Dilatometer, x-ray diffraction, scanning electron microscopy and differential thermal analysis/thermo gravimetric analysis were used to evaluate the thermal, phase detection, micro structural and weight loss changes by increasing concentration of ZrO2 on base porcelain composition. At 1350 °C, for the composition having 20 wt% ZrO2 with 10 wt% alumina, the maximum density was observed 2.81 g cm-3 with a porosity of 2.23%. The highest tensile strength of 41 ± 3 MPa is observed for the same sample composition. The minimum value of thermal expansion coefficient is found to be in the range of 10-6 for the sample with 30 wt% ZrO2 content sintered at 1350 °C compared to other prepared samples. Similarly, the highest dielectric value (5.1-4.4) having dielectric loss (0.08-0.12) is achieved for the sample with 30 wt% ZrO2 content sintered at 1350 °C in the frequency range of 4-20 GHz at room temperature. According to the mechanical properties, the composition having 20 wt% ZrO2 on base ceramic porcelain composition has enormous potential to serve as a high strength refractory material. For dielectric properties, the composition having 30 wt% ZrO2 is more suitable for the electrical application.

  4. Experimental study on critical breaking stress of float glass under elevated temperature

    International Nuclear Information System (INIS)

    Wang, Yu; Wang, Qingsong; Shao, Guangzheng; Chen, Haodong; Sun, Jinhua; He, Linghui; Liew, K.M.

    2014-01-01

    Highlights: • Critical breaking stresses of clear, ground and coated glass were measured. • Breaking stress and strain of smooth glass were measured from 25 °C to 400 °C. • At approximately 100 °C, critical stress reached the minimum value. • Surface treatment and ambient temperature have notable effects on glass breaking. - Abstract: Cracking and subsequent fallout of glass may significantly affect fire dynamics in compartments. Moreover, the breaking tensile stress of glass, a crucial parameter for breakage occurrence, is the least well known among mechanical properties. In this work, a series of experiments were conducted, through mechanical tensile tests, to directly measure the breaking stress of float glass using Material Testing System 810 apparatus. Clear, ground and coated glass samples with a thickness of 6 mm were measured under ambient conditions, with a room temperature of 25 °C. The breaking stress of smooth glass samples was also measured at 75 °C, 100 °C, 125 °C, 150 °C, 200 °C, 300 °C and 400 °C, respectively. The results show that surface treatment may decrease the critical tensile stress of glass panes. The average breaking stress also fluctuates considerably, from 26.60 to 35.72 MPa with the temperature variations investigated here. At approximately 100 °C, critical stress reached the minimum value at which glass breakage occurs more easily. In addition, the thermal expansion coefficient was established using a thermal dilatometer, to obtain the maximum temperature difference float glass can withstand. It is intended that these results will provide some practical guidelines for fire safety engineers

  5. Effects of superplastic deformations on thermophysical properties of tetragonal zirconia polycrystals

    International Nuclear Information System (INIS)

    Motohashi, Y.; Wan, C.; Sakuma, T.; Harjo, S.; Shibata, T.; Ishihara, M.; Baba, S.; Hoshiya, T.

    2004-01-01

    Neutron irradiation studies on superplastic zirconia-based ceramics are now in progress as an innovative basic project using the High-temperature Engineering Test Reactor (HTTR) in Japan. The characteristics of the zirconia-based engineering components, made through the formation of superplastic, may be strongly affected by their response to transient or steady-state heat flow. Reliable thermophysical properties such as the coefficients of thermal expansion and thermal conductivity are, therefore, needed to estimate and predict the influence of a high-temperature environment. Accordingly, one of this project's targets is to study the thermophysical properties of superplastic zirconia-based ceramics. The first stage of the research addresses the effects of superplastic deformations on the thermophysical properties of a typical superplastic ceramic, 3 mol% yttria-stabilised tetragonal zirconia polycrystals (3Y-TZP), in its un-irradiated state. First, superplastic tensile deformations were conducted on 3Y-TZP specimens under different conditions in order to obtain specimens with different microstructural characteristics. Afterwards, the following actions were taken: - Specific heat measurements were conducted on the specimens at temperatures ranging from 473 K to 1273 K. - The thermal diffusivity was measured using a laser flash method. The thermal conductivity was then calculated from the measured thermal diffusivity, specific heat and density. - The linear thermal expansion was measured by a push-rod type dilatometer from 300 K to 1473 K. The coefficient of linear thermal expansion (CTE) was estimated from the thermal expansion data. The results obtained from the above measurements are discussed, as is the microstructural evolution caused by the superplastic deformations. It was found that the specific heat was almost independent of microstructural evolution, whereas the thermal diffusivity, thermal conductivity and thermal expansion were quite sensitive to

  6. Short- and long- term ageing effects on the phase transformation in Au-49.5 at % Cd

    International Nuclear Information System (INIS)

    Kelly, G.L.; Finlayson, T.R.; Ersez, T.; Smith, T.F.

    1999-01-01

    Full text: Gold-Cadmium alloys of approximately equiatomic composition are widely studied as model systems for the shape-memory effect and 'rubber-elasticity'. Rubber-elasticity occurs after ageing for a time in the low-temperature martensite phase. This ageing is accompanied by an increase in the martensite → austenite phase transformation temperature (A s ). The ageing dependence of the transformation is a critical problem when finding applications for the shape-memory effect in these materials. The origin of the ageing effect is controversial with proposed mechanisms including stabilisation of the martensite by a change in short range order or pinning of the martensite by defects. In the present study, a Au-49.5at%Cd alloy has been subjected to a series of ageing times and the phase transformation temperatures monitored using a push-rod dilatometer. One test series comprising a range of ageing times was completed and then the sample was aged in the martensite phase for several months before re-testing. Both test series show that ageing in the martensite phase increases the temperature of the reverse transformation (A s ) as expected. Previous work had suggested that all effects of any previous ageing treatments were obliterated by a single cycle through the martensite-austenite-martensite transformations. The present study shows that this is not the case. The A f and A s temperatures for each ageing time in the test series had increased by several degrees after a year of ageing and this increase was maintained despite repeated cycling through the phase transformations

  7. STUDY OF THERMAL BEHAVIOUR ON TITANIUM ALLOYS (TI-6AL-4V

    Directory of Open Access Journals (Sweden)

    VASUDEVAN D

    2017-08-01

    Full Text Available Titanium is recognized for its strategic importance as a unique lightweight, high strength alloyed structurally efficient metal for critical, high-performance aircraft, such as jet engine and airframe components. Titanium is called as the "space age metal" and is recognized for its high strength-to-weight ratio. Today, titanium alloys are common, readily available engineered metals that compete directly with stainless steel and Specialty steels, copper alloys, nickel based alloys and composites. Titanium alloys are needed to be heat treated in order to reduce residual stress developed during fabrication and to increase the strength. Titanium (Ti-6Al-4V alloy is an alpha, beta alloy which is solution treated at a temperature of 950 ºC to attain beta phase. This beta phase is maintained by quenching and subsequent aging to increase strength. Thermal cycling process was carried out for Ti-6Al-4V specimens using forced air cooling. Heat treated titanium alloy specimen was used to carry out various tests before and after thermal cycling, The test, like tensile properties, co-efficient of thermal expansion, Microstructure, Compression test, Vickers Hardness was examined by the following test. Coefficient of Thermal expansion was measured using Dilatometer. Tensile test was carried out at room temperature using an Instron type machine. Vickers's hardness measurement was done on the same specimen as used for the microstructural observation from near the surface to the inside specimen. Compression test was carried out at room temperature using an Instron type machine. Ti‐6Al‐4V alloy is a workhorse of titanium industry; it accounts for about 60 percent of the total titanium alloy production. The high cost of titanium makes net shape manufacturing routes very attractive. Casting is a near net shape manufacturing route that offers significant cost advantages over forgings or complicated machined parts.

  8. Polymerization Behavior and Mechanical Properties of High-Viscosity Bulk Fill and Low Shrinkage Resin Composites.

    Science.gov (United States)

    Shibasaki, S; Takamizawa, T; Nojiri, K; Imai, A; Tsujimoto, A; Endo, H; Suzuki, S; Suda, S; Barkmeier, W W; Latta, M A; Miyazaki, M

    The present study determined the mechanical properties and volumetric polymerization shrinkage of different categories of resin composite. Three high viscosity bulk fill resin composites were tested: Tetric EvoCeram Bulk Fill (TB, Ivoclar Vivadent), Filtek Bulk Fill posterior restorative (FB, 3M ESPE), and Sonic Fill (SF, Kerr Corp). Two low-shrinkage resin composites, Kalore (KL, GC Corp) and Filtek LS Posterior (LS, 3M ESPE), were used. Three conventional resin composites, Herculite Ultra (HU, Kerr Corp), Estelite ∑ Quick (EQ, Tokuyama Dental), and Filtek Supreme Ultra (SU, 3M ESPE), were used as comparison materials. Following ISO Specification 4049, six specimens for each resin composite were used to determine flexural strength, elastic modulus, and resilience. Volumetric polymerization shrinkage was determined using a water-filled dilatometer. Data were evaluated using analysis of variance followed by Tukey's honestly significant difference test (α=0.05). The flexural strength of the resin composites ranged from 115.4 to 148.1 MPa, the elastic modulus ranged from 5.6 to 13.4 GPa, and the resilience ranged from 0.70 to 1.0 MJ/m 3 . There were significant differences in flexural properties between the materials but no clear outliers. Volumetric changes as a function of time over a duration of 180 seconds depended on the type of resin composite. However, for all the resin composites, apart from LS, volumetric shrinkage began soon after the start of light irradiation, and a rapid decrease in volume during light irradiation followed by a slower decrease was observed. The low shrinkage resin composites KL and LS showed significantly lower volumetric shrinkage than the other tested materials at the measuring point of 180 seconds. In contrast, the three bulk fill resin composites showed higher volumetric change than the other resin composites. The findings from this study provide clinicians with valuable information regarding the mechanical properties and

  9. The effect of microarc oxidation and excimer laser processing on the microstructure and corrosion resistance of Zr–1Nb alloy

    International Nuclear Information System (INIS)

    Yang, Jiaoxi; Wang, Xin; Wen, Qiang; Wang, Xibing; Wang, Rongshan; Zhang, Yanwei; Xue, Wenbin

    2015-01-01

    The main purpose of this research was to investigate the effect of microarc oxidation (MAO) and excimer laser processing on the corrosion resistance of Zr–1Nb alloy in service environment. The pre-oxide film was fabricated on the surface of Zr–1Nb cladding tubes by MAO processing, and then subjected to KrF excimer laser irradiation. The surface morphology of the pre-oxide film was observed using a scanning electron microscope; phase compositions and quantities were determined using an X-ray diffraction; surface roughness was determined using a profilometer; and thermal expansion coefficient was measured using a dilatometer. Autoclave experiments were conducted for 94 days in an aqueous condition of 360 °C under 18.6 MPa in 0.01 mol/L LiOH solutions. The results showed that MAO + laser treatment resulted in a significant increase in the corrosion resistance of Zr–1Nb cladding tubes at high temperatures, because laser melting and etching could lead to a reduction in surface roughness and an increase in compactness of the pre-oxide film, and laser processing could promote the transformation of m-ZrO 2 phase to t-ZrO 2 phase. The best corrosion resistance was obtained when the pulse energy was 500 mJ, scanning speed was 0.13 mm/s, and pulse number was 2400. - Highlights: • Pre-oxide film was fabricated on Zr–1Nb cladding tube by MAO+ excimer laser processing. • Excimer laser processing induced the transformation of m-ZrO 2 to t-ZrO 2 . • The Rietveld quantitative analysis of the pre-oxide film was made. • We investigated the high temperature corrosion and corrosion mechanism of the oxide film. • The parameters of MAO+ excimer laser processing were optimized.

  10. The effect of microarc oxidation and excimer laser processing on the microstructure and corrosion resistance of Zr–1Nb alloy

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jiaoxi, E-mail: yangjiaoxi@bjut.edu.cn [Institute of Laser Engineering, Beijing University of Technology, Beijing 100124 (China); Wang, Xin; Wen, Qiang; Wang, Xibing [Institute of Laser Engineering, Beijing University of Technology, Beijing 100124 (China); Wang, Rongshan; Zhang, Yanwei [Suzhou Nuclear Power Research Institute, Suzhou 215004 (China); Xue, Wenbin [College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

    2015-12-15

    The main purpose of this research was to investigate the effect of microarc oxidation (MAO) and excimer laser processing on the corrosion resistance of Zr–1Nb alloy in service environment. The pre-oxide film was fabricated on the surface of Zr–1Nb cladding tubes by MAO processing, and then subjected to KrF excimer laser irradiation. The surface morphology of the pre-oxide film was observed using a scanning electron microscope; phase compositions and quantities were determined using an X-ray diffraction; surface roughness was determined using a profilometer; and thermal expansion coefficient was measured using a dilatometer. Autoclave experiments were conducted for 94 days in an aqueous condition of 360 °C under 18.6 MPa in 0.01 mol/L LiOH solutions. The results showed that MAO + laser treatment resulted in a significant increase in the corrosion resistance of Zr–1Nb cladding tubes at high temperatures, because laser melting and etching could lead to a reduction in surface roughness and an increase in compactness of the pre-oxide film, and laser processing could promote the transformation of m-ZrO{sub 2} phase to t-ZrO{sub 2} phase. The best corrosion resistance was obtained when the pulse energy was 500 mJ, scanning speed was 0.13 mm/s, and pulse number was 2400. - Highlights: • Pre-oxide film was fabricated on Zr–1Nb cladding tube by MAO+ excimer laser processing. • Excimer laser processing induced the transformation of m-ZrO{sub 2} to t-ZrO{sub 2}. • The Rietveld quantitative analysis of the pre-oxide film was made. • We investigated the high temperature corrosion and corrosion mechanism of the oxide film. • The parameters of MAO+ excimer laser processing were optimized.

  11. Uranium dioxide sintering Kinetics and mechanisms under controlled oxygen potentials

    International Nuclear Information System (INIS)

    Freitas, C.T. de.

    1980-06-01

    The initial, intermediate, and final sintering stages of uranium dioxide were investigated as a function of stoichiometry and temperature by following the kinetics of the sintering reaction. Stoichiometry was controlled by means of the oxygen potential of the sintering atmosphere, which was measured continuously by solid-state oxygen sensors. Included in the kinetic study were microspheres originated from UO 2 gels and UO 2 pellets produced by isostatic pressing ceramic grade powders. The microspheres sintering behavior was examined using hot-stage microscopy and a specially designed high-temperature, controlled atmosphere furnace. This same furnace was employed as part of an optical dilatometer, which was utilized in the UO 2 pellet sintering investigations. For controlling the deviations from stoichiometry during heat treatment, the oxygen partial pressure in the sintering atmosphere was varied by passing the gas through a Cu-Ti-Cu oxygen trap. The trap temperature determined the oxygen partial pressure of the outflowing mixture. Dry hydrogen was also used in some of the UO sub(2+x) sintering experiments. The determination of diametrial shrinkages and sintering indices was made utilizing high-speed microcinematography and ultra-microbalance techniques. It was observed that the oxygen potential has a substantial influence on the kinetics of the three sintering stages. The control of the sintering atmosphere oxygen partial pressure led to very fast densification of UO sub(2+x). Values in the interval 95.0 to 99.5% of theoretical density were reached in less than one minute. Uranium volume diffusion is the dominant mechanism in the initial and intermediate sintering stages. For the final stage, uranium grain boundary diffusion was found to be the main sintering mechanism. (Author) [pt

  12. Three-axial Fiber Bragg Grating Strain Sensor for Volcano Monitoring

    Science.gov (United States)

    Giacomelli, Umberto; Beverini, Nicolò; Carbone, Daniele; Carelli, Giorgio; Francesconi, Francesco; Gambino, Salvatore; Maccioni, Enrico; Morganti, Mauro; Orazi, Massimo; Peluso, Rosario; Sorrentino, Fiodor

    2017-04-01

    Fiber optic and FBGs sensors have attained a large diffusion in the last years as cost-effective monitoring and diagnostic devices in civil engineering. However, in spite of their potential impact, these instruments have found very limited application in geophysics. In order to study earthquakes and volcanoes, the measurement of crustal deformation is of crucial importance. Stress and strain behaviour is among the best indicators of changes in the activity of volcanoes .. Deep bore-hole dilatometers and strainmeters have been employed for volcano monitoring. These instruments are very sensitive and reliable, but are not cost-effective and their installation requires a large effort. Fiber optic based devices offer low cost, small size, wide frequency band, easier deployment and even the possibility of creating a local network with several sensors linked in an array. We present the realization, installation and first results of a shallow-borehole (8,5 meters depth) three-axial Fiber Bragg Grating (FBG) strain sensor prototype. This sensor has been developed in the framework of the MED-SUV project and installed on Etna volcano, in the facilities of the Serra La Nave astrophysical observatory. The installation siteis about 7 Km South-West of the summit craters, at an elevation of about 1740 m. The main goal of our work is the realization of a three-axial device having a high resolution and accuracy in static and dynamic strain measurements, with special attention to the trade-off among resolution, cost and power consumption. The sensor structure and its read-out system are innovative and offer practical advantages in comparison with traditional strain meters. Here we present data collected during the first five months of operation. In particular, the very clear signals recorded in the occurrence of the Central Italy seismic event of October 30th demonstrate the performances of our device.

  13. Thermal Characteristic Of AIMg2 Cladding And Fuel Plates Of U3Si2-Al With Various Uranium Loading

    International Nuclear Information System (INIS)

    Aslina, Br. G.; Suparjo; Aggraini, D.; Hasbullah, N.

    1998-01-01

    Thermal characteristic analyzed in this paper included linear expansion value, coefficient expansion, and enthalpy of cladding material fuel core and fuel plate of U 3 Si 2 -AI. Before analyzing, the fresh cladding of AIMg2 (without treatment) and the rolled AIMg2 were annealed at temperature of 425 o C for 1 hour, and the fuel plates of U 3 Si 2 -AI was prepared for various uranium loading of 0.9 - 3.6 - 4.2 - 4.8 and 5.2 g/cm 3 . Linear expansion nominal value and expansion coefficient were analyzed by using Dilatometer whereas enthalpy determination used Differential Thermal Analysis (DTA). The linear expansion and expansion coefficient analysis was performed to study the dimension cladding and of fuel plates during their stay in the reactor core, whereas determination of enthalpy was carried out to estimate the energy absorbed and released by fuel meat of U 3 Si 2 -AI to the cooling water through AlMg2 as a cladding. The result showed that the linear expansion and expansion coefficient of fresh AIMg2 cladding, rolled AIMg2 and fuel plates of U 3 Si 2 -AI are increased with the increase of temperature as well as the increase of uranium loading. The enthalpy measure showed that the enthalpy of fresh AIMg2 is smaller than that of rolled AIMg2 but melting temperature of fresh AIMg2 is greater than that of rolled AIMg2. The enthalpy of fuel plates and meat of U 3 Si 2 -AI is less than that of plates of U 3 Si 2 -AI. The enthalpy of fuel platers and meat of U 3 Si 2 -AI decrease with the increase of uranium loading. It is concluded that the fuel meat more reactive than fuel plates of U 3 Si 2 -AI

  14. Electrochemical characterization of carbon coated bundle-type silicon nanorod for anode material in lithium ion secondary batteries

    International Nuclear Information System (INIS)

    Halim, Martin; Kim, Jung Sub; Choi, Jeong-Gil; Lee, Joong Kee

    2015-01-01

    Highlights: • Bundle-type silicon nanorods (BSNR) were synthesized by metal assisted chemical etching. • Novel bundle-type nanorods electrode showed self-relaxant characteristics. • The self-relaxant property was enhanced by increasing the silver concentration. • PAA binder enhanced the self-relaxant property of the silicon material. • Carbon coated BSNR (BSNR@C) has evidently provided better cycle performance. - Abstract: Nanostructured silicon synthesis by surface modification of commercial micro-powder silicon was investigated in order to reduce the maximum volume change over cycle. The surface of micro-powder silicon was modified using an Ag metal-assisted chemical etching technique to produce nanostructured material in the form of bundle-type silicon nanorods. The volume change of the electrode using the nanostructured silicon during cycle was investigated using an in-situ dilatometer. Our result shows that nanostructured silicon synthesized using this method showed a self-relaxant characteristic as an anode material for lithium ion battery application. Moreover, binder selection plays a role in enhancing self-relaxant properties during delithiation via strong hydrogen interaction on the surface of the silicon material. The nanostructured silicon was then coated with carbon from propylene gas and showed higher capacity retention with the use of polyacrylic acid (PAA) binder. While the nano-size of the pore diameter control may significantly affect the capacity fading of nanostructured silicon, it can be mitigated via carbon coating, probably due to the prevention of Li ion penetration into 10 nano-meter sized pores

  15. Monitoring unrest in a large silicic caldera, the long Valley-inyo craters volcanic complex in east-central California

    Science.gov (United States)

    Hill, D. P.

    1984-06-01

    Recent patterns of geologic unrest in long Valley caldera in east-central California emphasize that this large, silicic volcanic system and the adjacent, geologically youthful Inyo-Mono Craters volcanic chain are still active and capable of producing locally hazardous volcanic eruptions. A series of four magnitude -6 earthquakes in May 1980 called attention to this current episode of unrest, and subsequent activity has included numerous earthquake swarms in the south moat of the caldera accompanied by inflation of the resurgent dome by more than 50 cm over the last five years. The seismicity associated with this unrest is currently monitored by a network of 31 telemetered seismic stations with an automatic processing system that yelds hypocentral locations and earthquake magnitudes in near-real time. Deformation of the ground is monitored by a) a series of overlapping trilateration networks that provide coverage ranging from annual measurements of regional deformation to daily measurements of deformation local to the active, southern section of the caldera, b) a regional network of level lines surveyed annually, c) a regional network of precise gravity stations occupied annually, d) local, L-shaped level figures surveyed every few months, and e) a network of fourteen borehole tiltmeter clusters (two instruments in each cluster) and a borehole dilatometer, the telemetered signals from which provide continuous data on deformation rates. Additional telemetered data provide continuous information on fluctuations in the local magnetic field, hydrogen gas emission rates at three sites, and water level and temperatures in three wells. Continuous data on disharge rates and temperatures from hot springs and fumaroles are collected by several on-site recorders within the caldera, and samples for liquid and gas chemistry are collected several times per year from selected hot springs and fumaroles.

  16. ALLUVIAL DEPOSITS AS A SUBSOIL AND MATERIAL FOR BASIC HYDRO-TECHNICAL CONSTRUCTIONS

    Directory of Open Access Journals (Sweden)

    Jędrzej Wierzbicki

    2015-11-01

    Full Text Available The article presents an analysis of geotechnical parameters of the alluvial deposit (the areas of the Vistula and Warta river valleys with a view to using the soil as an earth construction material and as a foundation for buildings constructed on the grounds tested. Strength and deformation parameters of the subsoil tested were identified by the CPTU (cone penetration test and DMT (flat dilatometer test methods, as well as by the vane test (VT. The article includes the analysis of overconsolidation process of the soil tested and a formula for the identification of the overconsolidation ratio OCR. Equation 4 reflects the relation between the undrained shear strength and plasticity of the silts analyzed and the OCR value. The analysis resulted in the determination of the Nkt coefficient, which might be used to identify the undrained shear strength of both sediments tested. On the basis of a detailed analysis of changes in terms of the constrained oedometric modulus M0, the relations between the said modulus, the liquidity index and the OCR value were identified. Mayne’s formula (1995 was used to determine the M0 modulus from the CPTU test. The usefulness of the alluvial deposit as an earth construction material was analysed after their structure had been destroyed and compacted with a Proctor apparatus. In cases of samples characterized by different water content and soil particle density, the analysis of changes in terms of cohesion and the internal friction angle proved that these parameters are influenced by the soil phase composition. On the basis of the tests, it was concluded that the most desirable shear strength parameters are achieved when the silt is compacted below the optimum water content.

  17. Effect of Ba in the glass characteristics of cesium loaded iron phosphate glasses

    International Nuclear Information System (INIS)

    Joseph, Kitheri; Asuvathraman, R.; Vasudeva Rao, P.R.

    2015-01-01

    Radioactive 137 Cs extracted from high level nuclear waste, when immobilized in a suitable matrix can be used as a γsource in medical industry. Iron phosphate glass (IPG) is one of a suitable matrix for the immobilization of 137 Cs prior to the immobilization of 137 Cs in IPG, it is essential to optimize the immobilization conditions using natural (inactive) cesium. Glass characteristics of inactive Cs loaded iron phosphate glasses were already explored in our earlier studies. However, the change in glass characteristics of 137 Cs loaded iron phosphate glass to 137 Ba loaded iron phosphate glass need to be studied before the immobilization of 137 Cs in iron phosphate glass as 137 Cs transforms to 137 Ba due to nuclear transmutation ( 137 Cs(β,γ) 137 Ba). This paper reports the studies on such a behaviour by incorporating inactive Ba in cesium loaded iron phosphate glasses. Cs and Ba loaded iron phosphate glasses were prepared by melt quench technique in air using appropriate amounts of Fe 2 O 3 , NH 4 H 2 PO 4 , Ba(OH) 2.8 H 2 O and Cs 2 CO 3 . The chemicals were added such that the glass formed possesses the batch composition of (a) 21.4 wt. % Fe 2 O 3 -45 wt. % Cs 2 O-5 wt % BaO-P 2 O 5 (henceforth referred as IP50Cs45Ba5); (b) 21.4 wt. % Fe 2 O 3 -25 wt. % Cs 2 O-25 wt % BaO-P 2 O5 (henceforth referred as IP50Cs25Ba25). The thermal expansion measurements were also carried out using a home-built quartz push-rod dilatometer. The data related to change in thermal expansion behaviour, glass forming ability, glass stability and structural changes in phosphate network due to the partial replacement of Cs with Ba will also be discussed. (author)

  18. Effect of ZnO on the Thermal Properties of Tellurite Glass

    Directory of Open Access Journals (Sweden)

    H. A. A. Sidek

    2013-01-01

    Full Text Available Systematic series of binary zinc tellurite glasses in the form (ZnOx(TeO2 (where x=0 to 0.4 with an interval of 0.05 mole fraction have been successfully prepared via conventional melt cast-quenching technique. Their density was determined by Archimedes method with acetone as buoyant liquid. The thermal expansion coefficient of each zinc tellurite glasses was measured using L75D1250 dilatometer, while their glass transition temperature (Tg was determined by the SETARAM Labsys DTA/6 differential thermogravimetric analysis at a heating rate of 20 K min−1. The acoustic Debye temperature and the softening temperature (Ts were estimated based on the longitudinal (VL and shear ultrasonic (Vs wave velocities propagated in each glass sample. For ultrasonic velocity measurement of the glass sample, MATEC MBS 8000 Ultrasonic Data Acquisition System was used. All measurements were taken at 10 MHz frequency and at room temperature. All the thermal properties of such binary tellurite glasses were measured as a function of ZnO composition. The composition dependence was discussed in terms of ZnO modifiers that were expected to change the thermal properties of tellurite glasses. Experimental results show their density, and the thermal expansion coefficient increases as more ZnO content is added to the tellurite glass network, while their glass transition, Debye temperature, and the softening temperature decrease due to a change in the coordination number (CN of the network forming atoms and the destruction of the network structure brought about by the formation of some nonbridging oxygen (NBO atoms.

  19. Thermal expansion of UO2-Gd2O3 fuel pellets

    International Nuclear Information System (INIS)

    Une, Katsumi

    1986-01-01

    In recent years, more consideration has been given to the application of UO 2 -Gd 2 O 3 burnable poison fuel to LWRs in order to improve the core physics and to extend the burnup. It has been known that UO 2 forms a single phase cubic fluorite type solid solution with Gd 2 O 3 up to 20 - 30 wt.% above 1300 K. The addition of Gd 2 O 3 to UO 2 lattices changes the properties of the fuel pellets. The limited data on the thermal expansion of UO 2 -Gd 2 O 3 fuel exist, but those are inconsistent. UO 2 -Gd 2 O 3 fuel pellets were fabricated, and the linear thermal expansion of UO 2 and UO 2 -(5, 8 and 10 wt.%)Gd 2 O 3 fuel pellets was measured with a differential dilatometer over the temperature range of 298 - 1973 K. A sapphire rod of 6 mm diameter and 15.5 mm length was used as the reference material. After the preheating cycle, the measurement was performed in argon atmosphere. The results for UO 2 pellets showed excellent agreement with the data in literatures. The linear thermal expansion of UO 2 -Gd 2 O 3 fuel pellets showed the increase with increasing the Gd 2 O 3 content. Consideration must be given to this excessive expansion in the fuel design of UO 2 -Gd 2 O 3 pellets. The equations for the linear thermal expansion and density of UO 2 -Gd 2 O 3 fuel pellets were derived by the method of least squares. (Kako, I.)

  20. Process design of press hardening with gradient material property influence

    International Nuclear Information System (INIS)

    Neugebauer, R.; Schieck, F.; Rautenstrauch, A.

    2011-01-01

    Press hardening is currently used in the production of automotive structures that require very high strength and controlled deformation during crash tests. Press hardening can achieve significant reductions of sheet thickness at constant strength and is therefore a promising technology for the production of lightweight and energy-efficient automobiles. The manganese-boron steel 22MnB5 have been implemented in sheet press hardening owing to their excellent hot formability, high hardenability, and good temperability even at low cooling rates. However, press-hardened components have shown poor ductility and cracking at relatively small strains. A possible solution to this problem is a selective increase of steel sheet ductility by press hardening process design in areas where the component is required to deform plastically during crash tests. To this end, process designers require information about microstructure and mechanical properties as a function of the wide spectrum of cooling rates and sequences and austenitizing treatment conditions that can be encountered in production environments. In the present work, a Continuous Cooling Transformation (CCT) diagram with corresponding material properties of sheet steel 22MnB5 was determined for a wide spectrum of cooling rates. Heating and cooling programs were conducted in a quenching dilatometer. Motivated by the importance of residual elasticity in crash test performance, this property was measured using a micro-bending test and the results were integrated into the CCT diagrams to complement the hardness testing results. This information is essential for the process design of press hardening of sheet components with gradient material properties.

  1. The effects of annealing temperature and cooling rate on carbide precipitation behavior in H13 hot-work tool steel

    International Nuclear Information System (INIS)

    Kang, Minwoo; Park, Gyujin; Jung, Jae-Gil; Kim, Byung-Hoon; Lee, Young-Kook

    2015-01-01

    Highlights: • Unexpected Mo carbides formed during slow cooling from low annealing temperatures. • Mo carbides formed during the migration of Mo for a transition of Cr-rich carbide. • Mo carbides were precipitated at the boundaries of M 7 C 3 carbides and ferrite grains. • Annealing conditions for the precipitation of Mo carbides were discussed. - Abstract: The precipitation behavior of H13 hot-work tool steel was investigated as a function of both annealing temperature and cooling rate through thermodynamic calculations and microstructural analyses using transmission and scanning electron microscope and a dilatometer. The V-rich MC carbide and Cr-rich M 7 C 3 and M 23 C 6 carbides were observed in all annealed specimens regardless of annealing and cooling conditions, as expected from an equilibrium phase diagram of the steel used. However, Mo-rich M 2 C and M 6 C carbides were unexpectedly precipitated at a temperature between 675 °C and 700 °C during slow cooling at a rate of below 0.01 °C/s from the annealing temperatures of 830 °C and below. The solubility of Mo in both M 7 C 3 and ferrite reduces with decreasing temperature during cooling. Mo atoms diffuse out of both M 7 C 3 and ferrite, and accumulate locally at the interface between M 7 C 3 and ferrite. Mo carbides were form at the interface of M 7 C 3 carbides during the transition of Cr-rich M 7 C 3 to stable M 23 C 6

  2. Micro-nanocomposites Al2O3/ NbC/ WC and Al2O3/ NbC/ TaC

    International Nuclear Information System (INIS)

    Santos, Thais da Silva

    2014-01-01

    Alumina based ceramics belong to a class of materials designated as structural, which are widely used in cutting tools. Although alumina has good properties for application as a structural ceramics, composites with different additives have been produced with the aim of improving its fracture toughness and mechanical strength. New studies point out micro-nanocomposites, wherein the addition of micrometric particles should enhance mechanical strength, and nano-sized particles enhance fracture toughness. In this work, alumina based micro nanocomposites were obtained by including nano-sized NbC and micrometer WC particles at 2:1, 6:4, 10:5 and 15:10 vol% proportions, and also with the inclusion of nano-sized NbC and micrometer TaC particles at 2:1 vol% proportion. For the study of densification, micro-nanocomposites were sintered in a dilatometer with a heating rate of 20°C/min until a temperature of 1800°C in argon atmosphere. Based on the dilatometry results, specimens were sintered in a resistive graphite furnace under argon atmosphere between 1500°C and 1700°C by holding the sintering temperature for 30 minutes. Densities, crystalline phases, hardness and tenacity were determined, and micro-nanocomposites microstructures were analyzed. The samples Al 2 O 3 : NbC: TaC sintered at 1700 ° C achieved the greater apparent density (~ 95% TD) and the sample sintered at 1600 ° C showed homogeneous microstructure and increased hardness value (15.8 GPa) compared to the pure alumina . The compositions with 3% inclusions are the most promising for future applications. (author)

  3. Glass additive influence on the sintering behavior, microstructure and microwave magnetic properties of Cu-Bi-Zn co-doped Co2Z ferrites

    International Nuclear Information System (INIS)

    Hsiang, Hsing-I; Mei, Li-Then; Hsi, Chi-Shiung; Wu, Wei-Cheng; Cheng, Li-Bao; Yen, Fu-Su

    2011-01-01

    The Bi 2 O 3 -B 2 O 3 -ZnO-SiO 2 (BB35SZ) glass effects on the sintering behavior and microwave magnetic properties of Cu-Bi-Zn co-doped Co 2 Z ferrites were investigated to develop low-temperature-fired ferrites. The glass wetting characteristics on the Co 2 Z ferrite surface, X-ray diffractometer, scanning electron microscopy and a dilatometer were used to examine the BB35SZ glass effect on Co 2 Z ferrite densification and the chemical reaction between the glass and Co 2 Z ferrites. The results indicate that BB35SZ glass can be used as a sintering aid to reduce the densification temperature of Co 2 Z ferrites from 1300 to 900 o C. 3(Ba 0.9 Bi 0.1 O).2(Co 0.8 Cu 0.2 O).12(Fe 1.975 Zn 0.025 O 3 ) ferrite with 2 wt% BB35SZ glass can be densified below 900 o C, exhibiting an initial permeability of 3.4. This process provides a promising candidate for multilayer chip magnetic devices for microwave applications. - Research highlights: → Bi 2 O 3 -B 2 O 3 -ZnO-SiO 2 glass can effectively wet Co 2 Z ferrites and promote Co 2 Z ferrite densification. → The excess substitution of Bi and Zn (x=0.2) and glass addition enhanced Z phase decomposition into U, W and spinel phases, which resulted in magnetic property degradation. → 3(Ba 0.9 Bi 0.1 O).2(Co 0.8 Cu 0.2 O).12(Fe 1.975 Zn 0.025 O 3 ) ferrite with 2 wt% glass can be densified at below 900 o C and exhibits an initial permeability of 3.4, which provides a promising candidate for multilayer chip magnetic devices for microwave applications.

  4. Lightweighted ZERODUR for telescopes

    Science.gov (United States)

    Westerhoff, T.; Davis, M.; Hartmann, P.; Hull, T.; Jedamzik, R.

    2014-07-01

    The glass ceramic ZERODUR® from SCHOTT has an excellent reputation as mirror blank material for earthbound and space telescope applications. It is known for its extremely low coefficient of thermal expansion (CTE) at room temperature and its excellent CTE homogeneity. Recent improvements in CNC machining at SCHOTT allow achieving extremely light weighted substrates up to 90% incorporating very thin ribs and face sheets. In 2012 new ZERODUR® grades EXPANSION CLASS 0 SPECIAL and EXTREME have been released that offer the tightest CTE grades ever. With ZERODUR® TAILORED it is even possible to offer ZERODUR® optimized for customer application temperature profiles. In 2013 SCHOTT started the development of a new dilatometer setup with the target to drive the industrial standard of high accuracy thermal expansion metrology to its limit. In recent years SCHOTT published several paper on improved bending strength of ZERODUR® and lifetime evaluation based on threshold values derived from 3 parameter Weibull distribution fitted to a multitude of stress data. ZERODUR® has been and is still being successfully used as mirror substrates for a large number of space missions. ZERODUR® was used for the secondary mirror in HST and for the Wolter mirrors in CHANDRA without any reported degradation of the optical image quality during the lifetime of the missions. Some years ago early studies on the compaction effects of electron radiation on ZERODUR® were re analyzed. Using a more relevant physical model based on a simplified bimetallic equation the expected deformation of samples exposed in laboratory and space could be predicted in a much more accurate way. The relevant ingredients for light weighted mirror substrates are discussed in this paper: substrate material with excellent homogeneity in its properties, sufficient bending strengths, space radiation hardness and CNC machining capabilities.

  5. Electrochemical characterization of carbon coated bundle-type silicon nanorod for anode material in lithium ion secondary batteries

    Energy Technology Data Exchange (ETDEWEB)

    Halim, Martin [Center for Energy Convergence, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Energy and Environmental Engineering, Korea University of Science and Technology, Gwahangno, Yuseong-gu, Daejeon, 305-333 (Korea, Republic of); Kim, Jung Sub [Center for Energy Convergence, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Department of Material Science & Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Choi, Jeong-Gil [Department of Chemical Engineering, Hannam University, 461-1 Junmin-dong, Yusung-gu, Taejon 305-811 (Korea, Republic of); Lee, Joong Kee, E-mail: leejk@kist.re.kr [Center for Energy Convergence, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Energy and Environmental Engineering, Korea University of Science and Technology, Gwahangno, Yuseong-gu, Daejeon, 305-333 (Korea, Republic of)

    2015-04-15

    Highlights: • Bundle-type silicon nanorods (BSNR) were synthesized by metal assisted chemical etching. • Novel bundle-type nanorods electrode showed self-relaxant characteristics. • The self-relaxant property was enhanced by increasing the silver concentration. • PAA binder enhanced the self-relaxant property of the silicon material. • Carbon coated BSNR (BSNR@C) has evidently provided better cycle performance. - Abstract: Nanostructured silicon synthesis by surface modification of commercial micro-powder silicon was investigated in order to reduce the maximum volume change over cycle. The surface of micro-powder silicon was modified using an Ag metal-assisted chemical etching technique to produce nanostructured material in the form of bundle-type silicon nanorods. The volume change of the electrode using the nanostructured silicon during cycle was investigated using an in-situ dilatometer. Our result shows that nanostructured silicon synthesized using this method showed a self-relaxant characteristic as an anode material for lithium ion battery application. Moreover, binder selection plays a role in enhancing self-relaxant properties during delithiation via strong hydrogen interaction on the surface of the silicon material. The nanostructured silicon was then coated with carbon from propylene gas and showed higher capacity retention with the use of polyacrylic acid (PAA) binder. While the nano-size of the pore diameter control may significantly affect the capacity fading of nanostructured silicon, it can be mitigated via carbon coating, probably due to the prevention of Li ion penetration into 10 nano-meter sized pores.

  6. Fault failure with moderate earthquakes

    Science.gov (United States)

    Johnston, M. J. S.; Linde, A. T.; Gladwin, M. T.; Borcherdt, R. D.

    1987-12-01

    High resolution strain and tilt recordings were made in the near-field of, and prior to, the May 1983 Coalinga earthquake ( ML = 6.7, Δ = 51 km), the August 4, 1985, Kettleman Hills earthquake ( ML = 5.5, Δ = 34 km), the April 1984 Morgan Hill earthquake ( ML = 6.1, Δ = 55 km), the November 1984 Round Valley earthquake ( ML = 5.8, Δ = 54 km), the January 14, 1978, Izu, Japan earthquake ( ML = 7.0, Δ = 28 km), and several other smaller magnitude earthquakes. These recordings were made with near-surface instruments (resolution 10 -8), with borehole dilatometers (resolution 10 -10) and a 3-component borehole strainmeter (resolution 10 -9). While observed coseismic offsets are generally in good agreement with expectations from elastic dislocation theory, and while post-seismic deformation continued, in some cases, with a moment comparable to that of the main shock, preseismic strain or tilt perturbations from hours to seconds (or less) before the main shock are not apparent above the present resolution. Precursory slip for these events, if any occurred, must have had a moment less than a few percent of that of the main event. To the extent that these records reflect general fault behavior, the strong constraint on the size and amount of slip triggering major rupture makes prediction of the onset times and final magnitudes of the rupture zones a difficult task unless the instruments are fortuitously installed near the rupture initiation point. These data are best explained by an inhomogeneous failure model for which various areas of the fault plane have either different stress-slip constitutive laws or spatially varying constitutive parameters. Other work on seismic waveform analysis and synthetic waveforms indicates that the rupturing process is inhomogeneous and controlled by points of higher strength. These models indicate that rupture initiation occurs at smaller regions of higher strength which, when broken, allow runaway catastrophic failure.

  7. Short-period strain (0.1-105 s): Near-source strain field for an earthquake (M L 3.2) near San Juan Bautista, California

    Science.gov (United States)

    Johnston, M. J. S.; Borcherdt, R. D.; Linde, A. T.

    1986-10-01

    Measurements of dilational earth strain in the frequency band 25-10-5 Hz have been made on a deep borehole strainmeter installed near the San Andreas fault. These data are used to determine seismic radiation fields during nuclear explosions, teleseisms, local earthquakes, and ground noise during seismically quiet times. Strains of less than 10-10 on these instruments can be clearly resolved at short periods (< 10 s) and are recorded with wide dynamic range digital recorders. This permits measurement of the static and dynamic strain variations in the near field of local earthquakes. Noise spectra for earth strain referenced to 1 (strain)2/Hz show that strain resolution decreases at about 10 dB per decade of frequency from -150 dB at 10-4 Hz to -223 dB at 10 Hz. Exact expressions are derived to relate the volumetric strain and displacement field for a homogeneous P wave in a general viscoelastic solid as observed on colocated dilatometers and seismometers. A rare near-field recording of strain and seismic velocity was obtained on May 26, 1984, from an earthquake (ML 3.2) at a hypocentral distance of 3.2 km near the San Andreas fault at San Juan Bautista, California. While the data indicate no precursory strain release at the 5 × 10-11 strain level, a coseismic strain release of 1.86 nanostrain was observed. This change in strain is consistent with that calculated from a simple dislocation model of the event. Ground displacement spectra, determined from the downhole strain data and instrument-corrected surface seismic data, suggest that source parameters estimated from surface recordings may be contaminated by amplification effects in near-surface low-velocity materials.

  8. Swelling behaviour of Early Jurassic shales when exposed to water vapour

    Science.gov (United States)

    Houben, Maartje; Barnhoorn, Auke; Peach, Colin; Drury, Martyn

    2017-04-01

    The presence of water in mudrocks has a largely negative impact on production of gas, due to the fact that water causes swelling of the rock. Removing the water from the mudrock on the other hand could potentially shrink the rock and increase the matrix permeability. Investigation of the swelling/shrinkage behaviour of the rock during exposure to water vapour is of key importance in designing and optimizing unconventional production strategies. We have used outcrop samples of the Whitby Mudstone and the Posidonia shale [1], potential unconventional sources for gas in North-western Europe, to measure the swelling and shrinkage behaviour. Subsamples, 1 mm cubes, were prepared by the Glass Workshop at Utrecht University using a high precision digitally controlled diamond wafering saw cooled by air. The mm cubes were then exposed to atmospheres with different relative humidities either in an Environmental Scanning Electron Microscope (ESEM) or in a 3D dilatometer. So that the sample responses to exposure of water vapour could be measured. Parallel to the bedding we found a swelling strain between 0.5 and 1.5 %, perpendicular to the bedding though swelling strain varied between 1 and 3.5%. Volumetric swelling strain varied between 1 and 2% at a maximum relative humidity of 95%. Volumetric swelling strains measured in the Early Toarcian Shales are similar to the ones found in coal [2], where the results suggest that it might be possible to increase permeability in the reservoir by decreasing the in-situ water activity due to shrinkage of the matrix. [1] M.E. Houben, A. Barnhoorn, L. Wasch, J. Trabucho-Alexandre, C. J. Peach, M.R. Drury (2016). Microstructures of Early Jurassic (Toarcian) shales of Northern Europe, International Journal of Coal Geology, 165, 76-89. [2] Jinfeng Liu, Colin J. Peach, Christopher J. Spiers (2016). Anisotropic swelling behaviour of coal matrix cubes exposed to water vapour: Effects of relative humidity and sample size, International Journal of

  9. Study of the oxide reduction and interstitial contents during sintering of different plain carbon steels by in situ mass spectrometry in nitrogen atmosphere

    International Nuclear Information System (INIS)

    Momeni, Mohammad; Gierl, Christian; Danninger, Herbert

    2011-01-01

    Highlights: → Degassing phenomenon was studied in plain steels with different iron base powders. → The integrated area below the MS m12 graph can be used as an indicator of formed CO. → The integrated area is an indicator for in situ carbon loss in the specimen. → Carbon loss and area below the m12 graph can be correlated. - Abstract: Reduction of oxides covering powder particles is an important process during sintering and a prerequisite to form sintering contacts in PM parts. In the present research, degassing and reduction phenomena during sintering of plain carbon steels prepared from different atomised and sponge iron powders were studied by mass spectrometry (MS) in the dilatometer under protective N 2 atmosphere. Interstitial constituents were measured by carbon and oxygen analysis. According to the results, the major part of CO 2 is formed during carbothermic reduction of surface oxides in the low to moderate temperature range ( 600 deg. C, the main product of carbothermic reduction is CO and not CO 2 , but the former cannot be detected by MS in N 2 atmosphere. Signals m44 (CO 2 ) and m12 (C) were however found to be reliable indicators for CO. Similar intensity of mass 12 signals for both ASC and SC up to 1000 deg. C is consistent with equal carbon loss through carbothermic reaction. The integrated areas below the MS signal graphs, and thus the areas of the different degassing peaks obtained in the MS, were used as at least semi-quantitative estimation of the amount of gases formed, bearing in mind that MS is not really a quantitative analytical tool. Although a clearly defined relationship is not visible between oxygen loss and area below the m16 graph, the area for m12 can be used as an indicator for in situ carbon loss in the specimen. Increasing integrated areas for m12 and 16 between 800 and 1300 deg. C with only marginal enhancement of m44 indicates that the major part of oxides are removed as CO, in agreement with Boudouard equilibrium, at

  10. Ground Characterization Studies in Canakkale Pilot Site of LIQUEFACT Project

    Science.gov (United States)

    Ozcep, F.; Oztoprak, S.; Aysal, N.; Bozbey, I.; Tezel, O.; Ozer, C.; Sargin, S.; Bekin, E.; Almasraf, M.; Cengiz Cinku, M.; Ozdemir, K.

    2017-12-01

    The our aim is to outline the ground characterisation studies in Canakkale test site. Study is based on the EU H2020 LIQUEFACT project entitled "Liquefact: Assessment and mitigation of liquefaction potential across Europe: a holistic approach to protect structures / infrastructures for improved resilience to earthquake-induced liquefaction disasters". Objectives and extent of ground characterization for Canakkale test site includes pre-existing soil investigation studies and complementary field studies. There were several SPT and geophysical tests carried out in the study area. Within the context of the complementary tests, six (6) study areas in the test site were chosen and complementary tests were carried out in these areas. In these areas, additional boreholes were opened and SPT tests were performed. It was decided that additional CPT (CPTU and SCPT) and Marchetti Dilatometer (DMT) tests should be carried out within the scope of the complementary testing. Seismic refraction, MASW and micro tremor measurements had been carried out in pre-existing studies. Shear wave velocities obtained from MASW measurements were evaluated to the most rigorous level. These tests were downhole seismic, PS-logging, seismic refraction, 2D-ReMi, MASW, micro tremor (H/V Nakamura method), 2D resistivity and resonance acoustic profiling (RAP). RAP is a new technique which will be explained briefly in the relevant section. Dynamic soil properties had not been measured in pre-existing studies, therefore these properties were investigated within the scope of the complementary tests. Selection of specific experimental tests of the complementary campaign was based on cost-benefit considerations Within the context of complementary field studies, dynamic soil properties were measured using resonant column and cyclic direct shear tests. Several sieve analyses and Atterberg Limits tests which were documented in the pre-existing studies were evaluated. In the complementary study carried out

  11. Defects annihilation behavior of neutron-irradiated SiC ceramics densified by liquid-phase-assisted method after post-irradiation annealing

    Directory of Open Access Journals (Sweden)

    Mohd Idzat Idris

    2016-12-01

    Full Text Available Numerous studies on the recovery behavior of neutron-irradiated high-purity SiC have shown that most of the defects present in it are annihilated by post-irradiation annealing, if the neutron fluence is less than 1×1026 n/m2 (>0.1MeV and the irradiation is performed at temperatures lower than 973K. However, the recovery behavior of SiC fabricated by the nanoinfiltrated and transient eutectic phase (NITE process is not well understood. In this study, the effects of secondary phases on the irradiation-related swelling and recovery behavior of monolithic NITE-SiC after post-irradiation annealing were studied. The NITE-SiC specimens were irradiated in the BR2 reactor at fluences of up to 2.0–2.5×1024 n/m2 (E>0.1MeV at 333–363K. This resulted in the specimens swelling up ∼1.3%, which is 0.1% higher than the increase seen in concurrently irradiated high-purity SiC. The recovery behaviors of the specimens after post-irradiation thermal annealing were examined using a precision dilatometer; the specimens were heated at temperatures of up to 1673K using a step-heating method. The recovery curves were analyzed using a first-order model, and the rate constants for each annealing step were obtained to determine the activation energy for volume recovery. The NITE-A specimen (containing 12 wt% sintering additives recovered completely after annealing at ∼1573K; however, it shrank because of the volatilization of the oxide phases at 1673K. The NITE-B specimen (containing 18wt% sintering additives did not recover fully, since the secondary phase (YAG was crystallized during the annealing process. The recovery mechanism of NITE-A SiC was based on the recombination of the C and Si Frenkel pairs, which were very closely sited or only slightly separated at temperatures lower than 1223K, as well as the recombination of the slightly separated C Frenkel pairs and the migration of C and Si interstitials at temperatures of 1223–1573K. That is to say, the

  12. Study of deformation mechanisms of zinc bicrystals by thermal cycling (1963); Etude des mecanismes de deformation par cyclage thermique de bicristaux de zinc (1963)

    Energy Technology Data Exchange (ETDEWEB)

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

    1963-06-15

    The thermal cycling of zinc bicrystals has been studied in order to precise the thermal cycling growth mechanism, proposed by Burke and TURKALO, specially the dependence of 'equi-cohesive' temperature of grains on their mutual orientation and the parameters of the thermal cycle. Dilatometric studies showed that a bicrystal had no equi-cohesive temperature and that the grain-boundary develops stress at all temperatures. The creep of single and bicrystal have been studied on a dilatometer with stress below the Yield-stress. At constant temperature secondary creep appears after a transient period, at cycled temperature creep stays transient for strains of about 10{sup -4} to 10{sup -3} when the crystal is plastically hard. Micrographic investigations show that grain-boundary migration accompanies the grain boundary shearing and that cycles produce a strong polygonisation, corroborating the fact that the grain boundary remains a stress-generator and that creep occurs in the volume of grains. The discussion of results shows that the transient creep of hard grain in a bicrystal makes the thermal cycling irreversible and allows on elongation at each cycle if that have the lower expansion coefficient. (author) [French] Le cyclage thermique de bicristaux de zinc a ete etudie pour preciser le mecanisme de la croissance au cyclage thermique propose par BURKE et TURKALO, notamment la temperature d' 'equicohesion' des grains en fonction de leur orientation mutuelle et du regime de cyclage impose. Des essais dilatometriques ont montre qu'un bicristal ne presentait pas de temperature d'equicohesion et que le joint exercait des contraintes quelle que soit la temperature superieure du cycle. Le fluage de monocristaux et de bicristaux a ete etudie sur un dilatometre avec des contraintes inferieures a la limite elastique. A temperature constante le fluage secondaire apparait apres une periode transitoire, a temperature cyclee le fluage reste transitoire pour des deformations de l

  13. Thermal expansion of superconducting fulleride and borocarbide compounds

    International Nuclear Information System (INIS)

    Burkhart, G.J.

    1995-08-01

    In order to detact and analyze thermodynamic phase transitions, the investigation of the thermal expansion via capacitance dilatometry is a powerful experimental technique, due to the extremely high resolution (ΔL/L∝10 -8 -10 -10 ). With respect to the air sensitivity of the fullerides a dilatometer operating under inert atmosphere was designed and the thermal expansion of polycrystalline fulleride (Rb 3 C 60 , K 3 C 60 ) and borocarbide (YNi 2 B 2 C, LuNi 2 B 2 C) compounds was determined in the temperature range 5-320 K. Most effort was focused on a quantitative evaluation of the discontinuity in the thermal expansivity α at the superconducting transition. The results are discussed in the context of the Ehrenfest relation, which connects the jump in the thermal expansivity Δα with the pressure dependence of the superconducting transition temperature dT c /dp and the jump in the specific heat Δc p /T c at the superconducting transition. For Rb 3 C 60 and K 3 C 60 the jump in the specific heat can be derived via the Ehrenfest relation using the results of the thermal expansion measurements and the well-known pressure dependence of the superconducting transition temperature. The derived values for Rb 3 C 60 and K 3 Cu 60 are Δc p /T c ∝75mJ/molK 2 and Δc p /T c ∝64 mJ.molK 2 , respectively. The directly measured specific heat jump of K 3 C 60 gives approximately the same value of Δc p /T c , and, therefore, the use of the Ehrenfest relation on fullerides is justified. The specific heat jumps Δc p /T c , determined from theoretically derived values of the density of states at the Fermi level N(E F ) and the McMillan-parameter λ, exceed the experimental results by a factor of 1.5-2. This finding reflects the uncertainty concerning the superconducting parameters N(E F ) and λ. (orig.)

  14. Thermal expansion and microstructural analysis of experimental metal-ceramic titanium alloys.

    Science.gov (United States)

    Zinelis, Spiros; Tsetsekou, Athena; Papadopoulos, Triantafillos

    2003-10-01

    Statement of problem Low-fusing porcelains for titanium veneering have demonstrated inferior color stability and metal-ceramic longevity compared to conventional porcelains. This study evaluated the microstructure and thermal expansion coefficients of some experimental titanium alloys as alternative metallic substrates for low-fusing conventional porcelain. Commercially pure titanium (CP Ti) and various metallic elements (Al, Co, Sn, Ga, In, Mn) were used to prepare 8 titanium alloys using a commercial 2-chamber electric-arc vacuum/inert gas dental casting machine (Cyclarc). The nominal compositions of these alloys were the following (wt%): I: 80Ti-18Sn-1.5In-0.5Mn; II: 76Ti-12Ga-7Sn-4Al-1Co; III: 87Ti-13Ga; IV: 79Ti-13Ga-7Al-1Co; V: 82Ti-18In; VI: 75.5Ti-18In-5Al-1Co-0.5Mn; VII: 85Ti-10Sn-5Al; VIII: 78Ti-12Co-7Ga-3Sn. Six rectangular wax patterns for each test material (l = 25 mm, w = 3 mm, h = 1 mm) were invested with magnesia-based material and cast with grade II CP Ti (control) and the 8 experimental alloys. The porosity of each casting was evaluated radiographically, and defective specimens were discarded. Two cast specimens from CP Ti and alloys I-VIII were embedded in epoxy resin and, after metallographic grinding and polishing, were studied by means of scanning electron microscopy and wavelength dispersive electron probe microanalysis. One specimen of each material was utilized for the determination of coefficient of thermal expansion (CTE) with a dilatometer operating from room temperature up to 650 degrees C at a heating rate of 5 degrees C/minute. Secondary electron images (SEI) and compositional backscattered electron images (BEI-COMPO) revealed that all cast specimens consisted of a homogeneous matrix except Alloy VIII, which contained a second phase (possibly Ti(2)Co) along with the titanium matrix. The results showed that the coefficient of thermal expansion (CTE) varied from 10.1 to 13.1 x 10(-6)/ degrees C (25 degrees -500 degrees C), depending on

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-09-22

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

  16. Local fluid flow and borehole strain in the South Iceland Seismic Zone

    Science.gov (United States)

    Jónsson, S.; Segall, P.; Ágústsson, K.; Agnew, D.

    2003-12-01

    Installation of 175 borehole strainmeters is planned for PBO. It is therefore vital to understand the behavior of existing strainmeter installations. We investigate signals recorded by three borehole dilatometers in the south Iceland seismic zone following two Mw6.5 earthquakes in June 2000. Poroelastic relaxation has been documented following these events based on InSAR and water level data [Jónsson et al., 2003, Nature]. According to poroelastic theory for a homogeneous isotropic (unfractured) medium, the anticipated post-seismic volumetric strain has the same sign as the coseismic strain step. For example, coseismic compression results in pore-pressure increases; post-earthquake fluid drainage causes additional compression. However, we find that observed strain changes vary considerably between different instruments after the earthquakes. One instrument (HEL) behaves as expected with transient strain increasing with the same sign as the coseismic strain step. Another instrument (SAU) shows partial strain relaxation, opposite in sign to the coseismic signal. The third (BUR) exhibits complete strain relaxation by 3-4 days after the earthquakes (i.e., BUR does not record any permanent strain). BUR has responded in the same fashion to three different earthquakes and two volcanic eruptions, demonstrating conclusively that the transient response is due to processes local to the borehole. Fluid drainage from cracks can explain these observations. Rapid straining results in compression (extension) of the rock and strainmeter. Fluid filled fractures near the borehole transmit normal stress, due to the relative incompressibility of water. Thus, at short time scales the instrument records a coseismic strain step. With time, however, fluid flows out of (in to) the fractures, and the normal stress transmitted across the fractures decreases (increases). As the stress relaxes the strainmeter expands (contracts), reversing the coseismic strain. Barometric responses are

  17. Sintering of porous silver compacts at controlled heating rates in oxygen or argon

    International Nuclear Information System (INIS)

    Oliber, E.A; Cugno, C; Moreno, M; Esquivel, M; Haberkon, N; Fiscina, J.E; Gonzalez Oliver, C.J.R

    2002-01-01

    A submicronic (- 0.4μm grain size) spherical silver powder was mixed with 2wt% PVB and pressed into pellets (body A) of relative density (ρr) close to 0.54. The pellets were given a heat treatment at 235 o C for 4 hours (body B) in static air, after which the ρr values were increased by ∼2%. The preheated pellets (B) were densified in a vertical differential dilatometer, fitted with a silica head, at heating rates (hr) of 2, 4 and 10 o C min -1 under Ar or O 2 pure atmospheres. The total lineal densification [Δl(T)/lo, ΔI=Io-1(T) instantaneous thickness and lo: the initial thickness of the pellet] of the Ag-skeletons (B, of similar starting porosity) varied significantly upon changing either the (hr) or the atmosphere. It ranged from 8 to 12% giving still porous bodies of ρr∼0.80. After a small densification (stage (i)) each curve showed a clear Ti ( o C ) at which the densification (AD(T) exhibited a rapid increase (jump; stage (ii), and had a characteristic peak in densification rate (DR(T)). Then the AD continued by another mechanism (stage (iii)), related to grain growth, till the densification rate started to decrease probably due to densification (stage (iv)) of closed pores located at 4-grain corners. For every atmosphere the Ti increased with heating rate, and the Ti values for O 2 were 79- 105 o C lower than those for Ar. From DR kinetics analysis it is concluded that under O 2 stage (ii) is due to grain boundary diffusivity (gb) whereas for stage (iii) the volume (vol) diffusion is the main process. From detail densification fits it is shown for stage (iii) there is an initial contribution to densification coming up from an initial stage controlled by (gb) diffusion, and that the main process is still the intermediate stage with simultaneous grain growth controlled by volume self-diffusivity. For the Ar case the whole densification range appears to be controlled by (gb) diffusivity. Some impurity contamination of the Ag could produce a (gb

  18. Final report on initial samples supplied by LLNL for task 3.3 binder burnout and sintering schedule optimisation

    Energy Technology Data Exchange (ETDEWEB)

    Walls, P

    1999-01-04

    Sixteen of the twenty-one samples have been investigated using the scanning laser dilatometer. This includes all three types of samples with different preparation routes and organic content. Cracks were observed in all samples, even those only heated to 300 C. It was concluded that the cracking was occurring in the early part of the heat treatment before the samples reached 300 C. Increase in the rate of dilation of the samples occurred above 170 C which coincided with the decomposition of the binder/wax additives as determined by differential thermal analysis. A comparison was made with SYNROC C material (Powder Run 143), samples of which had been CIPed and green machined to a similar diameter and thickness as the 089 mm SRTC pucks. These samples contained neither binder nor other organic processing aids and had been kept in the same desiccator as the SRTC samples. The CIPed Synroc C samples sintered to high density with zero cracks. As the cracks made up only a small contribution to the change in diameter of the sample compared to the sintering shrinkage, useful information could still be gained from the runs. The sintering curves showed that there was much greater shrinkage of the Type III samples containing only the 5% PEG binder compared to the Type I which contained polyolefin wax as processing aid. Slight changes in gradient of the sintering curve were observed, however, due to the masking effect of the cracking, full analysis of the sintering kinetics cannot be conducted. Even heating the samples to 300 C at 1.0 or 0.5 C/min could not prevent crack formation. This indicated that heating rate was not the critical parameter causing cracking of the samples. Sectioning of green bodies revealed the inhomogeneous nature of the binder/lubricant distribution in the samples. Increased homogeneity would reduce the amount of binder/lubricant required, which should in turn, reduce the degree of cracking observed during heating to the binder burnout temperature. A

  19. Final Report on Initial Samples Supplied by LLNL for Task 3.3 Binder Burnout and Sintering Schedule Optimisation

    Energy Technology Data Exchange (ETDEWEB)

    Walls, P

    1999-01-04

    Sixteen of the twenty-one samples have been investigated using the scanning laser dilatometer. This includes all three types of samples with different preparation routes and organic content. Cracks were observed in all samples, even those only heated to 300 C. It was concluded that the cracking was occurring in the early part of the heat treatment before the samples reached 300 C. Increase in the rate of dilation of the samples occurred above 170 C which coincided with the decomposition of the binder/wax additives as determined by differential thermal analysis. A comparison was made with SYNROC C material (Powder Run 143), samples of which had been CIPed and green machined to a similar diameter and thickness as the 089mm SRTC pucks. These samples contained neither binder nor other organic processing aids and had been kept in the same desiccator as the SRTC samples. The CIPed Synroc C samples sintered to high density with zero cracks. As the cracks made up only a small contribution to the change in diameter of the sample compared to the sintering shrinkage, useful information could still be gained from the runs. The sintering curves showed that there was much greater shrinkage of the Type III samples containing only the 5% PEG binder compared to the Type I which contained polyolefin wax as processing aid. Slight changes in gradient of the sintering curve were observed, however, due to the masking effect of the cracking, full analysis of the sintering kinetics cannot be conducted. Even heating the samples to 300 C at 1.0 or 0.5 C/min could not prevent crack formation. This indicated that heating rate was not the critical parameter causing cracking of the samples. Sectioning of green bodies revealed the inhomogeneous nature of the binder/lubricant distribution in the samples. Increased homogeneity would reduce the amount of binder/lubricant required, which should in turn, reduce the degree of cracking observed during heating to the binder burnout temperature. A

  20. Thermodynamic studies at the low-dimensional spin systems HP-(VO)2P2O7, SrCu2(BO3)2, and azurite

    International Nuclear Information System (INIS)

    Bruehl, Andreas

    2007-01-01

    The present thesis deals with the low-temperature properties of three low-dimensional spin systems. The main experimental topic lies on measurements on the thermal expansion and on the specific heat, which were performed with a high-resolution capacitative dilatometer respectively an AC calorimeter facility. Because the so-called magnetic Grueneisen parameters, which describe the strength of the coupling of the magnetic partial system to the lattice, are throughout very large, especially the thermal-expansion measurements yield valuable information on the understanding of the treated systems. The central result of this thesis represent measurements on the high-pressure phase of (VO) 2 P 2 O 7 , briefly PP-VOPO. This system consists of alternating spin chains, whereby both exchange constants have similar values, i. e. only a weak alternation is present. In the thermal expansion an anomaly especially pronounced in chain direction at about 13 K. From the Grueneisen parameters determined by application of this model it can be concluded that the pronounced low-temperature anomaly in HP-VOPO is partly caused by the strong deformation dependence of the smaller of the two exchange constants, but partly also on the neighbourhood to a quantum critical point. The two-dimensional dimer system SrCu 2 (BO 3 ) 2 has gotten fame by the localization of the triplet excitations and the magnetization plateaus at certain fractions of the saturation magnetization conditioned by this. In the thermal expansion a distinct anomaly at the same temperature (T=8 K) is observed, as it also occurs in the specific heat. Finally measurements at the natural mineral azurite are presented, in which the spin are arranged in so-called diamond chains. In the magnetic susceptibility, the specific heat, and the thermal expansion a remarkable double structure occurs. Also the Λ-shaped antiferromagnetic order transition was studied and the phase diagram, consisting of paramagnetic, antiferromagnetic, and

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  2. Síntese e caracterização da cerâmica PZT dopada com íons bário Synthesis and characterization of barium-doped PZT ceramics

    Directory of Open Access Journals (Sweden)

    G. Gasparotto

    2003-04-01

    Full Text Available Pós de titanato zirconato de chumbo (PZT puros e dopados com bário foram obtidos pelo método de precursores poliméricos, conformados uniaxialmente, na forma de cilindros, utilizando 15 MPa, e prensados isostaticamente à 210MPa. Com o objetivo de estudar o comportamento de sinterização os compactos foram divididos em dois lotes. Sendo um sinterizado em um forno acoplado a um dilatômetro até a temperatura de 1300 °C e o outro sinterizado em forno tipo mufla, em sistema fechado, na temperatura de 1100 °C por 4 horas. Verificou-se que a adição do íon bário influencia na cinética de sinterização, na densificação final, na microestrutura e nas propriedades elétricas da cerâmica. A adição de bário aumenta a concentração da fase tetragonal no PZT, em função da substituição do chumbo por bário na rede perovskita. As amostras dopadas com concentrações maiores que 5,0 mol % em bário apresentaram segregação de PbO no contorno de grão, inibindo seu crescimento.Pure and barium doped lead zirconate titanate powders were obtained by the polymeric precursor method, uniaxially conformed in cylinders form using 15 MPa and pressing isostatically at 210 MPa. In order to study the sintering behaviour, the compacts were divided in two parts. One part was sintered in a dilatometer furnace till 1300 °C and the other one sintered in muffle furnace in the temperature of 1100 °C for 4 hours. It was verified that the addition of barium influences on the sintering kinetics, on the final density, microstructure and electric properties of the ceramics. The addition of barium increases the concentration of the tetragonal phase of PZT due to the substitution of lead by barium in the perovskite lattice. The samples doped with barium concentrations higher than 5.0 mol % leads to the segregation of PbO in the grain boundary, inhibiting grain growth.

  3. Decision Point 3 of Statement of Project Objectives (SOPO) “Recovery Act: Development of ITM Oxygen Technology for Integration with Advanced Industrial Systems”

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, Phillip

    2012-03-01

    Air Products is carrying out a scope of work under Phase 5 of the ITM Oxygen Cooperative Agreement to design, build, and operate a ceramic membrane fabrication facility (the -CerFabII) to enable production of membrane modules to supply a conceptual 2000 ton per day (TPD) ITM Oxygen facility (the -ITM Oxygen Development FacilityII), and to perform supporting development tasks in materials development and engineering development toward industrial, carbon capture and sequestration applications. Air Products is executing this project under the American Recovery and Reinvestment Act (ARRA) with the objective to accelerate the adoption of ITM Oxygen technology to help meet the country’s goals for deploying clean power plants. The objective of this Topical Report is to address the requirements of Decision Point 3 (DP3), which pertains to the status of all Tasks within Phase 5 and most notably the project status of the CerFab (Task 30) prior to authorization of funds for equipment purchase and construction of the facility. The intent of the DP3 is to provide the opportunity for DOE-NETL to review the status of these tasks and to make recommendations on forward project direction, including a recommendation to pass into Budget Period 8. In the area of Materials Development, Air Products has specified a high pressure dilatometer system which will enable measurements of material expansion of ITM ceramic compounds at very high oxygen partial pressures consistent with CCS applications. Under Task 28.2, subcontractor Ceramatec has made significant progress since DP2 in materials selection and process development and improvement for advanced architecture module fabrication. Ceramatec has determined a materials specification, and has selected a process for making the material. Ceramatec has further developed and selected the process for applying the membrane to unsintered advanced architecture wafers with a Two Step process. Ceramatec has built submodules meeting leak rate

  4. Recovery behavior of high purity cubic SiC polycrystals by post-irradiation annealing up to 1673 K after low temperature neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Idris, Mohd Idzat, E-mail: idzat.i.aa@m.titech.ac.jp [Department of Nuclear Engineering, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8550 Japan (Japan); The National University of Malaysia, School of Applied Physics, Faculty of Science and Technology, 43600 Bangi Selangor (Malaysia); Yamazaki, Saishun; Yoshida, Katsumi; Yano, Toyohiko [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8550 Japan (Japan)

    2015-10-15

    Two kinds of high purity cubic (β) SiC polycrystals, PureBeta-SiC and CVD-SiC, were irradiated in the BR2 reactor (Belgium) up to a fluence of 2.0–2.5 × 10{sup 24} (E > 0.1 MeV) at 333–363 K. Changes in macroscopic lengths were examined by post-irradiation thermal annealing using a precision dilatometer up to 1673 K with a step-heating method. The specimen was held at each temperature step for 6 h and the change in length of the specimen was recorded during each isothermal annealing step from 373 K to 1673 K with 50 K increments. The recovery curves were analyzed with the first order model, and rate constants at each annealing step were obtained. Recovery of defects, induced by neutron irradiation in high purity β-SiC, has four stages of different activation energies. At 373–573 K, the activation energy of PureBeta-SiC and CVD-SiC was in the range of 0.17–0.24 eV and 0.12–0.14 eV; 0.002–0.04 eV and 0.006–0.04 eV at 723–923 K; 0.20–0.27 eV and 0.26–0.31 eV at 923–1223 K; and 1.37–1.38 eV and 1.26–1.29 eV at 1323–1523 K, respectively. Below ∼1223 K the recombination occurred possibly for closely positioned C and Si Frenkel pairs, and no long range migration is deemed essential. Nearly three-fourths of recovery, induced by neutron irradiation, occur by this mechanism. In addition, at 1323–1523 K, recombination of slightly separated C Frenkel pairs and more long-range migration of Si interstitials may have occurred for PureBeta-SiC and CVD-SiC specimens. Migration of both vacancies may be restricted up to ∼1523 K. Comparing to hexagonal α-SiC, high purity β-SiC recovered more quickly in the lower annealing temperature range of less than 873 K, in particular less than 573 K. - Highlights: • Two kinds of high purity cubic (β) SiC polycrystals were irradiated. • Macroscopic lengths were examined by post-irradiation thermal annealing. • The recovery curves were analyzed with first order model.

  5. Thermal expansion and magnetostriction studies on iron pnictides

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Liran

    2010-09-19

    In this work, a 3-terminal capacitance dilatometer was set up and used for measurements of the thermal expansion and magnetostriction of novel superconducting iron pinictides and related materials. In particular, RFeAsO with R = La, Ce, Pr, Sm, Gd, LaFeASO{sub 1-x}F{sub x} and Ca(F{sub 1-c}Co{sub x}){sub 2}As{sub 2} have been investigated. The data on polycrystalline LaFeAsO{sub 1-x} are the first published thermal expansion data on this material. The lattice effects at the structural and the magnetic phase transition have been investigated and the phase diagram upon F-doping has been studied. A main result is the observation of a previously unknown fluctuation regime for the doping level x ≤ 0.04 over a large T range above the structural transition temperature T{sub S}. The absence of any structural anomalies in the normal state of the superconducting LaFeAlO{sub 1-x}F{sub x} samples with x ≥ 0.05 corroborates the discontinuous character of the phase boundary not only for the magnetism but also for the structural degrees of freedom. Similarly, the presence of high-temperature fluctuations is found for all RFeAsO undoped materials under study. The discussion of the probable origin of the fluctuations as well as the definition of the structural transition temperature T{sub S} are done. The low temperature features shown by the thermal expansion data for RFeAsO are caused by the onset of long range magnetic order of the 4f-moments and their different configurations. In particular, PrFeAsO, which has a very pronounced anomaly associated with Pr-ordering exhibits a large magnetostriction at low temperatures. By discussing this effect along with the magnetization, resistivity and other measurements, it is found that this large magneto-elastic effect may originate from the correlations between the momentum from Fe{sup 3+} and Pr{sup 3+}. Last, the thermal expansion of Ca(Fe{sub 1-x}Co{sub x}){sub 2}As{sub 2} 122 single crystals is investigated. Ca(Fe{sub 1-x}Co{sub x

  6. Contribution to the study of the sintering of finely divided alumina; Contribution a l'etude du frittage de l'alumine finement divisee

    Energy Technology Data Exchange (ETDEWEB)

    Vergnon, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1966-07-01

    Two crystalline forms of alumina, delta and alpha, were used to prepare compacts. The shrinkage of these compacts was investigated at different temperatures. The samples of alumina are composed of non porous, spherical particles, of a very high purity. Their mean diameter varies between 160 and 1 200 Angstrom for the delta alumina samples and between 400 and 1 200 Angstrom for the alpha alumina samples. The shrinkage of compacts, heated at a linearly increasing temperature (300 deg. C/h, slow heating) was studied in a A.D.A.M.E.L. dilatometer, modified to be used as a retractometer. The kinetics of the isothermal shrinkage of compacts after their rapid introduction (a few seconds, flash heating) in the high temperature zone of the furnace were followed with a photographic technique. It is shown that the heating rate influences the shrinkage of the compacts when they are heated at temperatures over 1 000 deg. C. The kinetics of the isothermal shrinkage, at temperature between 1000 deg. C and 1600 deg. C were thoroughly studied. Values of the apparent activation energy for the different classes of compacts are given. An interpretation of the results is proposed. It takes into account two different but interdependent mechanisms of sintering: the disappearance of porosity as a result of vacancy diffusion and the grain growth as a result of boundary migration. (author) [French] Deux formes cristallines de l'alumine, la forme delta et la forme alpha, ont ete utilisees pour confectionner des comprimes en vue d'une etude cinetique du frittage. Ces alumines d'une tres grande purete sont constituees de particules spheriques non poreuses, sensiblement homodispersees dont le diametre moyen varie entre 160 et 1200 Angstrom pour les echantillons de l'alumine delta et entre 400 et 1200 Angstrom pour ceux de l'alumine alpha. Le retrait des comprimes chauffes a temperature linerairement croissante (300 deg. C/h: chauffage lent) a ete suivi a l'aide du dilotometre A

  7. Contribution to the study of the sintering of finely divided alumina; Contribution a l'etude du frittage de l'alumine finement divisee

    Energy Technology Data Exchange (ETDEWEB)

    Vergnon, P. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1966-07-01

    Two crystalline forms of alumina, delta and alpha, were used to prepare compacts. The shrinkage of these compacts was investigated at different temperatures. The samples of alumina are composed of non porous, spherical particles, of a very high purity. Their mean diameter varies between 160 and 1 200 Angstrom for the delta alumina samples and between 400 and 1 200 Angstrom for the alpha alumina samples. The shrinkage of compacts, heated at a linearly increasing temperature (300 deg. C/h, slow heating) was studied in a A.D.A.M.E.L. dilatometer, modified to be used as a retractometer. The kinetics of the isothermal shrinkage of compacts after their rapid introduction (a few seconds, flash heating) in the high temperature zone of the furnace were followed with a photographic technique. It is shown that the heating rate influences the shrinkage of the compacts when they are heated at temperatures over 1 000 deg. C. The kinetics of the isothermal shrinkage, at temperature between 1000 deg. C and 1600 deg. C were thoroughly studied. Values of the apparent activation energy for the different classes of compacts are given. An interpretation of the results is proposed. It takes into account two different but interdependent mechanisms of sintering: the disappearance of porosity as a result of vacancy diffusion and the grain growth as a result of boundary migration. (author) [French] Deux formes cristallines de l'alumine, la forme delta et la forme alpha, ont ete utilisees pour confectionner des comprimes en vue d'une etude cinetique du frittage. Ces alumines d'une tres grande purete sont constituees de particules spheriques non poreuses, sensiblement homodispersees dont le diametre moyen varie entre 160 et 1200 Angstrom pour les echantillons de l'alumine delta et entre 400 et 1200 Angstrom pour ceux de l'alumine alpha. Le retrait des comprimes chauffes a temperature linerairement croissante (300 deg. C/h: chauffage lent) a ete suivi a l'aide du

  8. Studies on tempering at different temperatures of the beta phase retained by water quenching in uranium-chromium alloys containing from 0,37 to 4 atoms of chromium percent (1963); Etude du revenu a differentes temperatures de la phase beta retenue par trempe a l'eau dans les alliages uranium-chrome contenant de 0,37 a 4 atomes pour cent de chrome (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Degois, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1962-07-15

    The author made a systematic study of the annealing of the beta phase retained by water-quenching in uranium-chromium alloys of concentrations between 0.37 and 4 of chromium percent. It is shown that alloys containing less than 1 atom per cent are transformed at temperatures between room temperature and 250 deg. C according to a bainitic process involving activation energies of the order of 14,500 cal/mole. Alloys containing more than 1 at. per cent are transformed at temperature between 400 and 650 deg. C by way of a germination and growth process involving an activation energy of the order of 33,000 cal/mole. The limit of solubility of chromium in beta uranium plays a fundamental part in the transformations of the alloys. The TTT curves of beta {yields} alpha transformation were drawn by the use of a thermo-dilatometer of very low inertia. The transformation law may be expressed 1 x = exp. (kt){sup n}; x represents the degree of progression of the transformation, k a coefficient dependent on the temperature, and n an exponent depending only on the composition of the alloy. A micrographic and crystallographic study confirmed the results found by dilatometry; in particular it was possible to measure the progression rates of the transformation. (author) [French] L'auteur a fait une etude systematique du revenu de la phase beta retenue par trempe a l'eau dans les alliages uranium-chrome de teneurs comprises entre 0,37 et 4 atomes pour cent de chrome. Il a montre que les alliages qui contiennent moins de 1 atome pour cent de chrome se transforment aux temperatures comprises entre la temperature ordinaire et 250 deg. C selon un processus bainitique mettant en jeu des energies d'activatlon de l'ordre de 14500 cal/mole. Les alliages qui renferment plus de 1 atome pour cent de chrome se transforment aux temperatures comprises entre 400 et 650 deg. C suivant un processus de germination et croissance mettant en jeu une energie d'activation de l'ordre de -33000 cal/mole. La

  9. Densification and crystalization kinetics of mullite diphasic gels from non_isothermal dilatometry experiments

    Directory of Open Access Journals (Sweden)

    Orgaz, Felipe

    2008-12-01

    Full Text Available Mullite (3 AI2O3_2 SiO2 was processed by mixing silica and alumina colloids at pH below 3 in a high shear blender. The gels were sieved to ‹ 125 microns and cold isostatically pressed to form rods. The various processes involved during the sintering process such as condensation-polymerization and the competition between mullite crystallization and densification were analysed from constant heating rate equations and rate controlled sintering dilatometer experiments. Changes in the slopes permitted the identification of such processes and the activation energy for mullitization was calculated. Fast firing (20-30 K/min in the critical mullitization temperature range of 1230-1505ºC and low heating rates (2-3 K/min in the viscous flow densification intervals of below 1230ºC and higher than 1505 gives rise to near full density and fine grain microstructures of sintered mullite. Fast firing and high (0.5 to 1 % /min densification rate controlled processes seem to be the most suitable approaches to high density gel processed mullite. Amorphous silica is the rate controlling mechanism for the viscous flow densification process before alumina is solved and nucleation and crystallization of mullite appears. Deviations from the linear Frenkel model for viscous flow are also observed.

    Mullita de composición (3Al2O3 -2 SiO2 ha sido preparada mezclando coloides de sílice y alúmina en un mezclador de alta velocidad a pH inferior a 3. Los geles formados eran secados, tamizados por debajo de 125 micras y prensados isostáticamrente para formar varillas de unos 6 mm de diámetro. Los diferentes procesos que ocurren durante el proceso de sinterización, tales como polimerización- condensación y la competición entre cristalización y densificación, han sido analizados utilizando las ecuaciones de ecuaciones de velocidad de calentamiento constantte y experimentos

  10. Obtención de espumas a partir de residuos de pizarra

    Directory of Open Access Journals (Sweden)

    Cambronero, L. E. G.

    2005-12-01

    Full Text Available The objective of the present work is the recovery of slate wastes into a raw material for the ceramic industry. Foams are obtained without any addition of foaming agent thanks to the transformation of component present on the slate during heating. A glass base material with a closed porosity, gray color and density value around to 0,3g/cm3 has been obtained. Raw material is the slate waste as slurry, after cutting roofing slates. After drying, the slate powders were die pressed to achieve green samples, which were sintered in N2-5%H2 atmosphere at different temperatures, as well as in air as reference material at 1150ºC. Dilatometer behavior was studied on die pressed slate powders under both atmospheres as well as XRay diffraction in order to determine the crystalline phases on sintered materials. Sintered density decreases as temperature increases under non-oxidant atmosphere, which leads to decrease the mechanical properties with the temperature when the foam structure is developed (over 1075ºC on N2-5%H2 atmosphere.

    La transformación de los residuos de pizarra de techar en materias primas no tradicionales de la industria cerámica, es el objetivo del presente trabajo. Sin la adición de agentes espumantes, mediante la alteración que sufren los componentes de la pizarra cuando la misma es sometida a un calentamiento en atmósfera no oxidante, se han alcanzado espumas de poro cerrado o cerámica porosa de color gris oscuro con densidades próximas a 0,3 g/cm3 en las que las paredes están formadas principalmente por una fase vítrea. La materia prima empleada se obtiene por secado de lodos procedentes de las operaciones de corte de la pizarra para techar. Los compactos en verde obtenidos en matriz flotante se sinterizaron en atmósfera de N2-5% H2 a distintas temperaturas, así como en aire a 1150ºC como material de referencia y se empleó la difracción de rayos X para determinar las fases cristalinas presentes en los materiales

  11. MARSite-MARMARA SUPERSITE: Accomplishments and Outlook

    Science.gov (United States)

    Meral Ozel, Nurcan; Necmioglu, Ocal; Ergintav, Semih; Oguz Ozel, Asım; Italiano, Franco; Favali, Paolo; Bigarre, Pascal; Cakir, Ziyadin; Geli, Louis; Aochi, Hideo; Bossu, Remy; Zulfikar, Can; Sesetyan, Karin

    2017-04-01

    MARsite Project, funded under FP7-ENV.2012 6.4-2 (Grant 308417) and successfully implemented to Marmara Region during 2014-2016 indicated that focusing on the monitoring of the region and the integration of data from land, sea and space and the processing of this composed data based on sound earth-science research is an effective tool for mitigating damage from future earthquakes. This was achieved by monitoring the earthquake hazard through the ground-shaking and forecast maps, short- and long-term earthquake rate forecasting and time-dependent seismic hazard maps to make important risk-mitigation decisions regarding building design, insurance rates, land-use planning, and public-policy issues that need to balance safety and economic and social interests. MARSite has demonstrated the power of the use of different sensors in the assessment of the earthquake hazard. In addition to the more than 30 scientific publication within the MARsite Project framework, a multidisciplinary innovative borehole seismic observatory and a dilatometer have been installed within MARSite where its a data can be used for a range of seismic studies. Due to the encouraging results obtained from this experiment, it was determined that in the future likely smaller number of stations will be required reducing the cost of national seismic networks. The technical infrastructure of the continuous GPS stations of MAGNET network has been updated within MARSite. Tsunami hazard studies in MARSite in Marmara Sea showed that the tsunami hazard in the Marmara Region is primarily due to submarine landslides triggered by an earthquake and a conceptual Tsunami Early Warning System in the Marmara region strongly coupled with the strong ground motion and existing Earthquake Early Warning System was developed. The existing Earthquake Early Warning and Rapid Response system in the Marmara Region was improved and the installation and test of a pilot seismic landslide monitoring system was taken place in the

  12. Some of the properties of plutonium and the aluminium-plutonium alloy; Quelques proprietes du plutonium et de l'alliage aluminium-plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Abramson, R; Boucher, R; Fabre, R; Monti, H [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1959-07-01

    1- Study of the physical properties of plutonium. 1) Study of the allotropy of plutonium. a) Thermal analysis: the apparatus used and the measurement technique are briefly described. The transition point temperatures and the corresponding heats of transformation have been determined. Finally, the results of the particular study of certain transition points are given. b) Dilatometry. The dilatometric analysis of the phase changes of plutonium has been carried out by means of the Chevenard dilatometer with photographic recording. The testing conditions (heating and cooling speeds, isotherm plateaux) have been varied in order to determine accurately the characteristics of each transition, particularly the {delta} {yields} {gamma} transition on cooling. 2) Micrography of plutonium. For the accurate preparation of metallographic samples the electrolytic polishing must be rapid, which implies a mechanical polishing of excellent quality. Information is given on new attacking reagents which show the structure of the metal very clearly. 2- Study of aluminium-plutonium alloys. Comparative study of Al-Pu and Al-U alloys rich in aluminium. a) Thermal analysis. The liquids and fusion temperatures of the eutectic Al-XAl{sub 4}, have been accurately determined. From the measurement of the heats of fusion the exact composition of the eutectic alloy has been determined. b) Thermal treatments. The eutectic coalescence kinetics have been studied by a micrographic method and by following the evolution of hardness. The results obtained show that the phenomenon is more rapid in Al-Pu alloys than in Al-U alloys. c) Micrographic study of the transition XAl{sub 3} {yields} XAl{sub 4}. The peritectic reaction XAl{sub 3} + liq. {yields} XAl{sub 4} has been suppressed by quenching. The transformation of the XAl{sub 3} phase to the solid phase has been studied as well as the effect of small additions of silicon on the kinetics of this reaction. (author) [French] 1- Etude des proprietes

  13. 3D characterization of crack propagation in building stones

    Science.gov (United States)

    Fusi, N.; Martinez-Martinez, J.; Crosta, G. B.

    2012-04-01

    Opening of fractures can strongly modify mechanical characteristics of natural stones and thus significantly decrease stability of historical and modern buildings. It is commonly thought that fractures origin from pre-existing structures of the rocks, such as pores, veins, stylolythes (Meng and Pan, 2007; Yang et al., 2008). The aim of this study is to define relationships between crack formation and textural characteristics in massive carbonate lithologies and to follow the evolution of fractures with loading. Four well known Spanish building limestones and dolostones have been analysed: Amarillo Triana (AT): a yellow dolomitic marble, with fissures filled up by calcite and Fe oxides or hydroxides; Blanco Tranco (BT): a homogeneous white calcitic marble with pore clusters orientated parallel to metamorphic foliation; Crema Valencia (CV): a pinkish limestone (mudstone), characterized by abundant stilolythes, filled mainly by quartz (80%) and kaolin (11%); Rojo Cehegin (RC): a red fossiliferous limestone (packstone) with white veins, made up exclusively by calcite in crystals up to 300 micron. All lithotypes are characterized by homogeneous mineralogical composition (calcitic or dolomitic) and low porosity (<10%). Three cores 20 mm in diameter have been obtained for each lithotype. Uniaxial compressive tests have been carried out in order to induce sample fracturing by a series of successive steps with application of a progressive normal stress. Crack propagation has been checked after each stress level application by microCT-RX following Hg impregnation of the sample (in a Hg porosimeter). Combination of both tests (microCT-RX and Hg porosimeter) guarantees a better characterization of small defects and their progressive propagation inside low-porous rocks than by employing solely microCT-RX (Fusi et al., 2009). Due to the reduced dimensions of sample holder (dilatometers) in porosimeter, cores have been cut with a non standard h/d = 1.5. Several cycles of: a) Hg

  14. Cinética de sinterização para sistemas à base de SnO2 por taxa de aquecimento constante Sintering kinetics for SnO2-based systems by constant heating rate

    Directory of Open Access Journals (Sweden)

    S. M. Tebcheran

    2003-04-01

    in small concentrations as densifying aids for this oxide. In the present study the sintering kinetics of tin oxide was studied considering the effect of sintering atmosphere and of the MnO2 concentration. SnO2-MnO2 systems were prepared from the polymeric precursors method and the obtained powders were characterized by surface area by the BET method. SnO2 powders with varied MnO2 concentrations were pressed in cylindrical shape, and sintered in a dilatometer furnace with constant heating rate and controlled atmospheres. Sintered samples were characterized by scanning electron microscopy. The influence of atmosphere (argon, air or CO2 as well as of the MnO2 concentrations on the sintering kinetics was determined. The kinetics data of linear shrinkage were analyzed in terms of kinetic models for the initial stage of sintering (Woolfrey and Bannister as well as for the global sintering (Su e Johnson allowing the determination of the apparent activation energy. Following the determination of the master sintering curve the apparent activation energy of all sintering process were determined as well as its dependence with the atmosphere and manganese concentrations. Based on these values and on the n exponent, determined by the classical grain growth equation, it was concluded that the most probable sintering mechanism is grain boundary diffusion with surface redistribution controlling the kinetics.