Sample records for dilatometers

  1. Geotechnical risk analysis by flat dilatometer (DMT)

    Amoroso, Sara; Monaco, Paola


    In the last decades we have assisted at a massive migration from laboratory testing to in situ testing, to the point that, today, in situ testing is often the major part of a geotechnical investigation. The State of the Art indicates that direct-push in situ tests, such as the Cone Penetration Test (CPT) and the Flat Dilatometer Test (DMT), are fast and convenient in situ tests for routine site investigation. In most cases the DMT estimated parameters, in particular the undrained shear strength su and the constrained modulus M, are used with the common design methods of Geotechnical Engineering for evaluating bearing capacity, settlements etc. The paper focuses on the prediction of settlements of shallow foundations, that is probably the No. 1 application of the DMT, especially in sands, where undisturbed samples cannot be retrieved, and on the risk associated with their design. A compilation of documented case histories that compare DMT-predicted vs observed settlements, was collected by Monaco et al. (2006), indicating that, in general, the constrained modulus M can be considered a reasonable "operative modulus" (relevant to foundations in "working conditions") for settlement predictions based on the traditional linear elastic approach. Indeed, the use of a site investigation method, such as DMT, that improve the accuracy of design parameters, reduces risk, and the design can then center on the site's true soil variability without parasitic test variability. In this respect, Failmezger et al. (1999, 2015) suggested to introduce Beta probability distribution, that provides a realistic and useful description of variability for geotechnical design problems. The paper estimates Beta probability distribution in research sites where DMT tests and observed settlements are available. References Failmezger, R.A., Rom, D., Ziegler, S.R. (1999). "SPT? A better approach of characterizing residual soils using other in-situ tests", Behavioral Characterics of Residual Soils, B

  2. Density Measurement of Liquid Metals Using Dilatometer

    Lianwen WANG; Qingsong MEI


    The dilatometer method for density measurement of liquid metals was improved to give a high measurement accuracy with simple operation. The density of liquid tin was measured and the results are in agreement with values in literature. The melting point density of liquid Sn was measured to be 6.966×103 Kg·m-3 and the temperature (T) dependence of the density (ρ) for liquid Sn can be well described by a polynomial equation ρ(T)=7.406 - 9.94 × 10-4T + 2.12 × 10-7T2.

  3. PBX 9502 ratchet growth experiments on a dilatometer

    Thompson, Darla Graff [Los Alamos National Laboratory; Brown, Geoff W [Los Alamos National Laboratory; Deluca, Racci [Los Alamos National Laboratory; Hagelberg, Stephanie [Los Alamos National Laboratory


    A Netzsch dilatometer has been used to probe the ratchet growth response of TATB-containing PBX 9502. Preliminary data are presented, showing test reproducibility and examining possible effects of density and/or the specific sequencing of different thermal ranges. We have also shown effects of thermal ramp rate on the test data, likely due to thermal equilibrium of the specimen environment.

  4. Use of the flat dilatometer (DMT) in landslides

    Amoroso, Sara; Monaco, Paola


    During the last decades we have assisted at a considerable shift from laboratory testing to in situ testing to the point that, today, in situ testing often represent the major part of a geotechnical investigation. Recommendations given in recent State-of-the-Art papers indicate that direct-push in situ tests, such as the Seismic Cone Penetration Test (SCPT) and the Seismic Dilatometer Test (SDMT), are fast and very convenient tests for routine site investigations. The aim of this paper is to describe the use of the flat dilatometer test (DMT) in landslide diagnosis and monitoring. In particular, a method is presented for detecting slip surfaces in overconsolidated clay slopes based on the inspection of the profiles of the horizontal stress index KD from DMT, as developed by Totani et al. (1997). In addition, the relaxation of the in situ horizontal stress σh, estimated from DMT, helps to locate a landslide. The paper illustrates by using different examples the capability of SDMT to identify the shear zones left remoulded by the occurrence of a landslide. Keywords: flat dilatometer, horizontal stress index, in situ horizontal stress References Totani G., Calabrese M., Marchetti S., Monaco, P. (1997). Use of in situ flat dilatometer (DMT) for ground characterization in the stability analysis of slopes. Proceeding of 14th International Conference on Soil Mechanics and Foundation Engineering, Hamburg, September 1997, vol. 1, pp. 607-610.

  5. High resolution miniature dilatometer based on an atomic force microscope piezocantilever

    Park, J.-H.; Graf, D.; Murphy, T. P.; Tozer, S. W. [National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310 (United States); Schmiedeshoff, G. M. [Department of Physics, Occidental College, Los Angeles, California 90041 (United States)


    Thermal expansion, or dilation, is closely related to the specific heat, and provides useful information regarding material properties. The accurate measurement of dilation in confined spaces coupled with other limiting experimental environments such as low temperatures and rapidly changing high magnetic fields requires a new sensitive millimeter size dilatometer that has little or no temperature and field dependence. We have designed an ultracompact dilatometer using an atomic force microscope piezoresistive cantilever as the sensing element and demonstrated its versatility by studying the charge density waves in alpha uranium to high magnetic fields (up to 31 T). The performance of this piezoresistive dilatometer was comparable to that of a titanium capacitive dilatometer.

  6. Borehole dilatometer installation, operation, and maintenance at sites in Hawaii

    Myren, G.D.; Johnston, M.J.S.; Mueller, R.J.


    In response to concerns about the potential hazard of Mauna Loa volcano in Hawaii, the USGS began efforts in 1998 to add four high-resolution borehole sites. Located at these sites are; strainmeters, tiltmeters, seismometers, accelerometers and other instrumentation. These instruments are capable of providing continuous monitoring of the magma movement under Mauna Loa. Each site was planned to provide multi-parameter monitoring of volcanic activity. In June of 2000, a contract was let for the core drilling of three of these four sites. They are located at Hokukano (west side of Mauna Loa) above Captain Cook, Hawaii; at Mauna Loa Observatory (11,737 feet near the summit), and at Mauna Loa Strip Road (east side of Mauna Loa). Another site was chosen near Halema'uma u' and Kilauea's summit, in the Keller deep well. (See maps). The locations of these instruments are shown in Figure 1 with their latitude and longitude in Table 1. The purpose of this network is to monitor crustal deformation associated with volcanic intrusions and earthquakes on Mauna Loa and Kilauea volcanoes. This report describes the methods used to locate sites, install dilatometers, other instrumentation, and telemetry. We also provide a detailed description of the electronics used for signal amplification and telemetry, plus techniques used for instrument maintenance. Instrument sites were selected in regions of hard volcanic rock where the expected signals from magmatic activity were calculated to be a maximum and the probability of earthquakes with magnitude 4 or greater is large. At each location, an attempt was made to separate tectonic and volcanic signals from known noise sources for each instrument type.

  7. A uniaxial stress capacitive dilatometer for high-resolution thermal expansion and magnetostriction under multiextreme conditions

    Küchler, R.; Stingl, C.; Gegenwart, P.


    Thermal expansion and magnetostriction are directional dependent thermodynamic quantities. For the characterization of novel quantum phases of matter, it is required to study materials under multi-extreme conditions, in particular, down to very low temperatures, in very high magnetic fields or under high pressure. We developed a miniaturized capacitive dilatometer suitable for temperatures down to 20 mK and usage in high magnetic fields, which exerts a large spring force between 40 to 75 N on the sample. This corresponds to a uniaxial stress up to 3 kbar for a sample with cross section of (0.5 mm)2. We describe design and performance test of the dilatometer which resolves length changes with high resolution of 0.02 Å at low temperatures. The miniaturized device can be utilized in any standard cryostat, including dilution refrigerators or the commercial physical property measurement system.

  8. A compact and miniaturized high resolution capacitance dilatometer for measuring thermal expansion and magnetostriction.

    Küchler, R; Bauer, T; Brando, M; Steglich, F


    We describe the design, construction, calibration, and two different applications of a miniature capacitance dilatometer. The device is suitable for thermal expansion and magnetostriction measurements from 300 K down to about 25 mK, with a resolution of 0.02 Å at low temperatures. The main body of the dilatometer is fabricated from a single block of a Be-Cu alloy by electrical discharge milling. This creates an extremely compact high-resolution measuring cell. We have successfully tested and operated dilatometers of this new type with the commonly used physical property measurement system by quantum design, as well as with several other cryogenic refrigeration systems down to 25 mK and in magnetic fields up to 20 T. Here, the capacitance is measured with a commercially available capacitance bridge. Using a piezoelectric rotator from Attocube Systems, the cell can be rotated at T = 25 mK inside of an inner vacuum chamber of 40 mm diameter. The miniaturized design for the one-axis rotation setup allows a rotation of 360°.

  9. The borehole dilatometer network of Mount Etna: A powerful tool to detect and infer volcano dynamics

    Bonaccorso, A.; Linde, A.; Currenti, G.; Sacks, S.; Sicali, A.


    A network of four borehole dilatometers has been installed on Etna in two successive phases (2010-2011 and 2014). The borehole dilatometers are installed in holes drilled at depths usually greater than 100 m, and they measure the volumetric strain of the surrounding rock with a nominal precision up to 10-11 in a wide frequency range (10-7-25 Hz). Here we describe the characteristics of the network and the results of the in situ calibrations obtained after the installations by different methods. We illustrate short-term strain changes recorded during several lava fountains erupted by Etna during 2011-2013, and we also show signal changes recorded at all four stations during the lava fountain on 28 December 2014. Analytical and numerical computations constrained the eruptions source depth and also its volume change that is related to the magma volume emitted. Finally, we show the potential of the signal in the medium term to reveal strain changes related to different phases of the volcanic activity.

  10. Dilatometer setup for low coefficient of thermal expansion materials measurements in the 140 K-250 K temperature range

    Spannagel, Ruven; Hamann, Ines; Sanjuan, Josep; Schuldt, Thilo; Gohlke, Martin; Johann, Ulrich; Weise, Dennis; Braxmaier, Claus


    Space applications demand light weight materials with excellent dimensional stability for telescopes, optical benches, optical resonators, etc. Glass-ceramics and composite materials can be tuned to reach very low coefficient of thermal expansion (CTE) at different temperatures. In order to determine such CTEs, very accurate setups are needed. Here we present a dilatometer that is able to measure the CTE of a large variety of materials in the temperature range of 140 K to 250 K. The dilatometer is based on a heterodyne interferometer with nanometer noise levels to measure the expansion of a sample when applying small amplitude controlled temperature signals. In this article, the CTE of a carbon fiber reinforced polymer sample has been determined with an accuracy in the 10-8 K-1 range.

  11. The world's smallest capacitive dilatometer, for high-resolution thermal expansion and magnetostriction in high magnetic fields

    Küchler, R.; Wörl, A.; Gegenwart, P.; Berben, M.; Bryant, B.; Wiedmann, S.


    For the characterization of novel quantum phases of matter, it is often required to study materials under multi-extreme conditions, in particular down to very low temperatures and in very high magnetic fields. We developed the world's smallest high-resolution capacitive dilatometer suitable for temperatures down to 10 mK and usage in high magnetic fields up to 37.5 T. Despite the extreme miniaturization, the capacitive dilatometer can resolve length changes down to 0.01 Å. This is an unprecedented resolution in a capacitive dilatometer of this compact size. Many cryogenic devices have limited space. Due to the extremely reduced cell size (3 cm3, 12 g), implementation or new applications in many of these sample space lacking devices are now possible. As an important example, the minute device can now be rotated in any standard cryostat, including dilution refrigerators or the commercial physical property measurement system. The present super compact design provides also for high resolution thermal expansion and magnetostriction measurements in a 15.2 mm diameter tube, enabling its use in the 32 mm bore, 37.5 T Bitter magnet at the High Field Magnet Laboratory in Nijmegen down to a temperature of 300 mK.

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

    Luckabauer, Martin; Sprengel, Wolfgang; Würschum, Roland


    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.

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

    Myren, Glenn; Johnston, Malcolm; Mueller, Robert


    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

  14. 扁铲侧胀试验在天津滨海新区软土中的应用%Application of flat dilatometer test in soft soil of the New Coastal Area of Tianjin

    李佐良; 杨爱武; 胡硕鹏


    简要介绍扁铲侧胀试验(DMT)的基本原理及一些应用成果,并将其应用于天津滨海新区软土的研究。结果表明:DMT对天津滨海新区的正常固结软土划分合理,但对吹填软土划分不够准确;DMT对应力历史的描述除粉土外符合实际情况;天津滨海新区扁铲土性指数ID值在0.3左右的软土的静止侧压力系数K0值为0.65,且真空预压将导致K0值变大。%The flat dilatometer test (DMT) theory and some application results are briefly introduced. DMT is used to study soft soil of the New Coastal Area of Tianjin. The results indicate that soil stratification for normal con-solidation clay is accurate, but not suitable for soft dredger soil. The description of stress history accords with the fact except silt. The lateral earth pressure coefficientK0 is 0.65 for soft soil of whichID is 0.3, and increases along with vacuum preloading.

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

    Campbell, Anne A., E-mail: [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Porter, Wallace D.; Katoh, Yutai [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Snead, Lance L. [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)


    Highlights: • Annealing of SiC via continuous dilatometry to determine irradiation temperature. • Wrote a program to analyze dilatometry results to determine irradiation temperature. • Dilatometry results are consistent with results from a historical technique. • Computer program was written in an open-source language and is available for others. - Abstract: 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.

  16. The Design and Testing of a High-Temperature Graphite Dilatometer


    Fillers, Principal Director, Mechanics and Materials Technology Center. P. M. Propp was the project officer for the Mission-Oriented Investigation and...only for the exchange and stimulation of ideas. W, Kyle Sneddon, Capt., USAF Paul M. Propp MOIE Program Manager Wright Laboratory West Coast Office

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

    Magalas L.B.


    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.

  18. Research on the predication of sandy soil liquefaction with flat dilatometer test%扁铲侧胀试验判别砂土的液化性研究




  19. 探析扁铲侧胀试验与单桥静力触探试验相关性%Correlation Analysis of the Flat Dilatometer Test and Cone Penetration Test




  20. Development of an optical dilatometer using a cryogenic refrigerator (3). Measurements for a single crystal silicon; Kogata reitoki wo michiita reza kanshoshii bochoritsu sokutei sochi no kaihatsu (3). Tankesho shirikon no sokutei kekka

    Yamada, N.; Okaji, M. [National Research laboratory of Metrology, Tsukuba (Japan)


    We have developed laser-interferential coefficient of linear expansion measuring device in order to carry out the absolute measurement of coefficient of linear expansion of solid material at low temperature. Since the cooling system by liquid helium has been adopted, in this system, there was a restriction for streamlining of the data acquisition and handling simplification of the equipment. This time, the equipment was newly constructed using the cryostat with the refrigerating machine with the vibration control mechanism. By measuring low temperature thermal expansion rate of the single crystal silicon in the equipment, and comparing with the promotion value by CODATA, the soundness of the equipment was confirmed. (NEDO)

  1. 基于连续冷却膨胀曲线的42CrMo4钢等温转变图的计算%Computation of Isothermal Transformation Diagrams of 42CrMo4 Steel from Dilatometer Measurements with Continuous Cooling

    F W Bach; M Schaper; Z Yu; F Nürnberger; T Gretzki; D Rodman; R Springer; 顾剑锋



  2. Inertance Tube Modeling and the Effects of Temperature


    compact and miniaturized high resolution capacitance dilatometer for measuring thermal expansion and magnetostriction Rev. Sci. Instrum. 83, 095102...acoustic power. KEYWORDS: Inertance tube, cryocoolers, pulse tube refrigerators, oscillating flow, computational fluid dynamics INTRODUCTION Pulse

  3. HETEK - Control of Early Age Cracking in Concrete

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


    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...

  4. USAF Space Sensing Cryogenic Considerations


    capacitance dilatometer for measuring thermal expansion and magnetostriction Rev. Sci. Instrum. 83, 095102 (2012) Compact radio-frequency resonator...enhancing when the refrigeration system is considered as part of an overall optimization problem. INTRODUCTION The use of cryogenics in space sensing

  5. Advanced Regenerators for Very Low Temperature Cryocoolers.


    solid. The density of candidate fullerene powder and formed samples will be measured by Archimedes’ principle in accordance with ASTM C373 -72...Coefficient of thermal expansion will be measured by a vitreous silica push rod dilatometer assembly in accordance with ASTM -E228-85 (reapproved 1989). The

  6. Effects of preoxidation on the swelling and softening of bituminous coals

    Maloney, D. J.; Jenkins, R. G.; Walker, Jr., P. L.


    A study was conducted to evaluate the applicability of a DuPont 942-TMA (Thermomechanical Analyzer) dilatometer system for the characterization of the swelling and softening properties of caking coals. The results of this investigation demonstrate the utility of this dilatometer system. Several parameters clearly defined with this unit are characteristic of the plastic transitions occurring upon carbonization. These include softening, dilation and resolidification temperature and volume contraction, expansion and total dilation values. The transition parameters measured with the 942-TMA unit are influenced significantly by coal particle size, dilatometer load, and heating rate. All transition temperatures exhibit marked increases with increasing heating rate. Softening temperatures decrease with increasing load and particle size. Dilation temperatures are essentially independent of dilatometer load effects and resolidification temperatures are independent of load and particle size over the range of conditions used in this study. Volume contraction and expansion values show an increase with decreasing coal particle size. Volume expansion values also exhibit strong heating rate and load dependencies. The results point up the great difficulty involved in obtaining truly fresh unoxidized coal samples. Storage of fine coal particles for extended periods of time in atmospheres with even slight oxygen concentrations show signs of weathering. Exposure of an HVA coal to dry air at ambient temperature has much less effect on subsequent swelling and softening properties than does exposure to moist air.

  7. Equipment for measuring autogenous RH-change and autogenous deformation in cement paste and concrete

    Hansen, Kurt Kielsgaard; Jensen, Ole Mejlhede


    Equipment for measuring autogenous RH-change and autogenous deformation in cement paste and concrete are presented. The equipment consists of a Rotronic Hygroskop DT including a measuring chamber for measuring autogenous RH-change in cement paste and concrete, a paste dilatometer for measuring...

  8. Groundwater level changes in a deep well in response to a magma intrusion event on Kilauea Volcano, Hawai'i

    Hurwitz, S.; Johnston, M.J.S.


    On May 21, 2001, an abrupt inflation of Kilauea Volcano's summit induced a rapid and large increase in compressional strain, with a maximum of 2 ??strain recorded by a borehole dilatometer. Water level (pressure) simultaneously dropped by 6 cm. This mode of water level change (drop) is in contrast to that expected for compressional strain from poroelastic theory, and therefore it is proposed that the stress applied by the intrusion has caused opening of fractures or interflows that drained water out of the well. Upon relaxation of the stress recorded by the dilatometer, water levels have recovered at a similar rate. The proposed model has implications for the analysis of ground surface deformation and for mechanisms that trigger phreatomagmatic eruptions.

  9. Influence Intensive Plastic Deformation on Phase Formation Process in Amorphous Alloys

    V.I. Lysov


    Full Text Available The influence of intensive plastic deformation on structure and properties of amorphous alloys were investigated experimentally. Using highly sensitive dilatometer techniques shown that intensive plastic deformation of amorphous alloys leads to increased of thermal stability interval that can be explained by a shift of the phase equilibria in heterogeneous system: amorphous matrix - frozen crystallization centers. Thus there is a dissolution frozen crystallization centers present in the original sample that confirmed by electron researches.

  10. Thermal expansion of ceramics around room temperature

    橋本, 忍; 安達, 信泰; 太田, 敏孝; 宮崎, 英敏; ハシモト, シノブ; アダチ, ノブヤス; オオタ, トシタカ; Hashimoto, Shinobu; Adachi, Nobuyasu; Ota, Toshitaka


    Thermal expansion of some ceramics, polymers and metals was measured by dilatometer around room temperature (from -140℃to +200℃), and compared with thermal expansion in the high temperature region. The CTE (coefficient of thermal expansion)of almost ceramics changed drastically between room temperature and high temperature region. On the other hand, the CTE ofmetals did not change between room temperature and high temperature region. The difference on thermal expansion betweenceramics and met...

  11. Thermal expansion of glassy polymers.

    Davy, K W; Braden, M


    The thermal expansion of a number of glassy polymers of interest in dentistry has been studied using a quartz dilatometer. In some cases, the expansion was linear and therefore the coefficient of thermal expansion readily determined. Other polymers exhibited non-linear behaviour and values appropriate to different temperature ranges are quoted. The linear coefficient of thermal expansion was, to a first approximation, a function of both the molar volume and van der Waal's volume of the repeating unit.


    HE Pingsheng; ZHOU Zhiqiang; WANG Gengchao; PAN Caiyuan; WU Renjie


    The volume change of the copolymer epoxy resins can be controlled by copolymerizing epoxy resin E51 with 3,9-di (5-norbornene-2, 2)-1, 5, 7, 11-tetraoxaspiro [5, 5] undecane (NSOC). During curing,the volume changes of copolymer epoxy resins with various amounts of NSOC were measured with a dilatometer. Cure process does not produce volume change when epoxy resin E51: NSOC is 5.88: 1 in equivalent.

  13. Liquid-phase sintering of Al with addition of Ti

    Romanov G.N.


    Full Text Available Samples made from aluminium-titanium elemental powder blend with titanium contents ranging from 5 to 20 at. % were prepared by die pressing and subsequent sintering under vacuum in a dilatometer quartz tube at 700, 800 and 900 °C. Dilatometric and heating curves of sintering were analysed and discussed in connection with X-ray data and results from microstructural investigations. .

  14. ZERODUR thermo-mechanical modelling and advanced dilatometry for the ELT generation

    Jedamzik, Ralf; Kunisch, Clemens; Westerhoff, Thomas


    Large amounts of low thermal expansion material are required for the upcoming ELT projects. The main mirror is designed using several hundreds of hexagonal 1.4 m sized mirror blanks. The M2 and M3 are monolithic 4 m class mirror blanks. The mirror blank material needs to fulfill tight requirements regarding CTE specification and homogeneity. Additionally the mirror blanks need to be dimensionally stable for more than 30 years. In particular, stress effects due to the changes in the environment shall not entail shape variation of more than 0.5 μm PV within 30 years. In 2010 SCHOTT developed a physically based model to describe the thermal and mechanical long time behavior of ZERODUR. The model enables simulation of the long time behavior of ZERODUR mirror blanks under realistic mechanical and thermal constraints. This presentation shows FEM simulation results on the long time behavior of the ELT M1, M2 and M3 mirror blanks under different loading conditions. Additionally the model results will be compared to an already 15 years lasting long time measurement of a ZERODUR sample at the German federal physical standardization institute (PTB). In recent years SCHOTT pushed the push rod dilatometer measurement technology to its limit. With the new Advanced Dilatometer CTE measurement accuracies of +- 3 ppb/K and reproducibilities of better 1 ppb/K have been achieved. The new Advanced Dilatometer exhibits excellent long time stability.

  15. Thermal expansion of PBX 9501 and PBX 9502 plastic-bonded explosives

    Thompson, Darla Graff [Los Alamos National Laboratory; Brown, Geoff W [Los Alamos National Laboratory; Deluca, Racci [Los Alamos National Laboratory; Giambra, Anna [Los Alamos National Laboratory; Sandstrom, Mary [Los Alamos National Laboratory


    Two applications of thermal expansion measurements on plastic-bonded explosive (PBX) composites are described. In the first dilatometer application, thermal expansion properties of HMX-based PBX 9501 are measured over a broad thermal range that includes glass and domain-restructuring transitions in the polymeric binder. Results are consistent with other thermal measurements and analyses performed on the composite, as well as on the binder itself. The second application used the dilatometer to distinguish the reversible and irreversible components of thermal expansion in PBX 9502, a TATB-based explosive. Irreversible expansion of the composite is believed to derive from the highly-anisotropic coefficient of thermal expansion (CTE) values measured on single T A TB crystals, although the mechanism is not well understood. Effects of specimen density, thermal ramp rate, and thermal range variation (warm first or cold first) were explored, and the results are presented and discussed. Dilatometer measurements are ongoing towards gaining insight into the mechanism(s) responsible for PBX 9502 irreversible thermal expansion.


    V. Kovalevsky


    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.

  17. Influence of Interfacial Carbide Layer Characteristics on Thermal Properties of Copper-Diamond Composites (Postprint)


    wettability of diamond is not an issue. Moreover, the solid-state processing can, in principle , be carried out at relatively low temperatures even for non...capacity. q was mea- sured using Archimedes ’ method, and D was measured with laser flash technique per ASTM E1461. The speci- mens for D measurement...respectively. The CTE of composites was measured with a push -rod dilatometer DIL 402 C (Manufacturer: NET- ZSCH-Gerätebau GmbH, Selb, Germany) per ASTM E228

  18. Magnetostriction measuring device based on an optical fiber sensor with an annular photodiode.

    de Manuel, V; Del Real, R P; Alonso, J; Guerrero, H


    A new simple and sensitive dilatometer to measure magnetostriction of ribbons has been developed, based on an optical fiber sensor using an annular photodiode. The optical fiber is used bidirectionally, both for emission and detection of light, simplifying the access to the ribbon under test. The working principle is based on the measurement by reflection of the longitudinal displacement of the ribbon end. For a Vitroperm amorphous ribbon of 100 mm length, 21 microm thickness, and 8.3 mm width, a displacement of 2.571 microm with a maximum uncertainty of 8 nm has been obtained.

  19. Dilatometric Investigation on Isothermal Transformation after Hot Deformation

    CHEN Ying; CHEN Qi-an


    The DAFT (deformation assistant ferrite transformation) of austenite and reverse DIFT (deformation induced ferrite transformation) during isothermal holding after deformation were investigated by means of hot deformation simulator with laser dilatometer. It is found that the reverse DIFT can occur in a wide temperature region, from the temperature above Ae3 to below A r3. However, during the isothermal holding, the reverse DIFT and DAFT of austenite take place, and therefore, the volume variation during holding time may be the combined effect of both phase transformations mentioned above. Nevertheless, the total volume and then the phase volume fraction change slowly, especially at lower holding temperature.

  20. The effects of ash and maceral composition of Azdavay and Kurucasile (Turkey) coals on coking properties

    Toroglu, I. [Zonguldak Karaelmas University, Zonguldak (Turkey). Faculty of Engineering


    In this study, investigations were made as to the effect of the maceral compositions and mineral matter content of Azdavay and Kurucasile coals on the coking property. Chemical and maceral analyses and coking properties were determined for the products of the float-sink procedure. The coking properties were established on the basis of free swelling index and Ruhr dilatometer tests. Maceral analyses showed that as the ash content of a coal containing both high and medium volatile matter increases, its effective maceral proportion decreases, and the coking property is affected in an unfavorable way.

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

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


    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...... is mainly based on experimental laboratory testing, followed by computer assisted data interpretation. The mentioned tools are used in testing the sand properties in shallow depth and examining any occurrence of an effect induced by the limited size of the laboratory set-up....

  2. Reaction sintering of the 2ZnO-TiO2 system

    Obradović N.


    Full Text Available Sintering kinetics of the mechanically activated ZnO-TiO2 system was studied. Mixtures of ZnO and TiO2 powders were mechanically activated using a high-energy ball mill for different time intervals from 0 to 300 minutes. Formal phenomenological analyses were performed in order to describe the specimen’s behavior during isothermal sintering at 1100oC. Non-isothermal sintering was investigated by dilatometer measurements up to 1100oC with a constant heating rate. The Dorn method was applied in order to give information on the activation energy. .

  3. Effect of MAE on the properties of phosphate edge-cladding glasses

    Fenggang Zhao; Guonian Wang; Lili Hu


    Edge-cladding is a key factor in improving saturated small signal gain coefficient βs of large laser disc glass. In this paper, the glasses were melted with traditional method. The influences of mixed alkali effect (MAE) on refractive index, thermal expansion coefficient α, glass transition temperature Tg, dilatometer softening temperature Td, and relative chemical durability of phosphate edge-cladding glasses were studied.The results reveal that when Li/(Na + Li) = 0.5, Tg, Td, and dissolution rate (DR) reach a minimal value.These results are preferred in phosphate edge-cladding glasses.

  4. Fine grain tungsten produced with nanoscale powder

    Tao Lin; Fang Zhao; Liying Zhang; Chengyi Wu; Zhimeng Guo


    Nanoscale tungsten powder was prepared by reducing nanoscale tungsten trioxide in hydrogen to WO2.90 and further to W powder. After compacted with a rubber die, the nanoscale tungsten powder was sintered in a high-temperature dilatometer to investigate its shrinkage process. The results show that the compact of the nanoscale tungsten powder starts to shrink at 1050℃ and ends at 1500℃. The shrinkage rate reaches the maximum value at 1210℃. The relative density of sintered samples is 96.4%, and its grain size is about 5.8 μm.

  5. Influence of Chemical Composition Variations on Densification During the Sintering of MOX Materials

    Vaudez, S.; Marlot, C.; Lechelle, J.


    The mixed uranium-plutonium oxide (MOX) fabrication process is based on the preparation of UO2 and PuO2 powders. The mixture is pelletized before being sintered at 1973 K (1700 °C) in a reducing atmosphere of Ar/4pctH2/H2O. This paper shows how the densification of MOX fuel is affected during sintering by the moisture content of the gas, the plutonium content of the fuel, and the carbon impurity content in the raw materials. MOX densification can be monitored through dilatometric measurements and gas releases can be continuously analyzed during sintering in terms of their quantity and quality. Variations in the oxygen content in the fuel can be continuously recorded by coupling the dilatometer furnace with an oxygen measurement at the gas outlet. Any carbon-bearing species released, such as CO, can be also linked to densification phenomena when a gas chromatograph is installed at the outlet of the dilatometer. Recommendations on the choice of sintering atmosphere that best optimizes the fuel characteristics have been given on the basis of the results reported in this paper.

  6. Aseismic strain episodes at Campi Flegrei, Italy

    Scarpa, Roberto; Amoruso, Antonella; Bilham, Roger; Di Lieto, Bellina; Errico, Antonio; Linde, Alan; Sacks, Selwyn


    Since spring 2004 a research project has been developed in Italy to install borehole Sacks-Evertson strainmeters (dilatometers) aimed to improve monitoring systems of the Italian volcanoes. 6 borehole dilatometers have been installed around Campi Flegrei and Vesuvius during 2004-2005 (Scarpa et al., 2007). This small network has been implemented by two arrays of long-baseline water tube tiltmeters installed in underground tunnels since 2008. Relevant strainmeter and tiltmeter data have been collected and analyzed at the instruments installed at Campi Flegrei during the recent unrest episodes. Renewed activity started since 2004-2005, characterized by a quite low rate of vertical vertical displacement, amounting initially to a few cm/year. A long term strain episode occurred during summer 2006, in correspondence to an increase of CO2 emission and displacements measured also by tiltmeters and GPS transducers. This strain episode preceded the seismic activity by few months, as also observed during the 1982 most significant unrest. Other aseismic slip episodes have been recorded in 2009, in correspondence of the renewal of gas emission activity at Solfatara, in 2010, one day before a seismic swarm, and in September 2012, few days before the most significant seismic swarm occurred after the 1982-1984 uplift. The time scale of these phenomena is ranging from some hours to several days, putting further constraints on the origin of ground uplifts at Campi Flegrei. Their location is compatible with the source inferred from long term deformation signals, at about 4 km depth beneath Pozzuoli.

  7. Prvé použitie horninového dilatometra na Slovensku – nové možnosti testovania deformačných vlastností skalných hornín in-situ

    Július Bohyník


    Full Text Available The basic problem of engineering geotechnical investigation is – with the exception of geological condition´s description – determination of specific geotechnical parameters of rock and soil on the site of future structure. In the case when detection of the rock massif`s parameters is desirable in the underground structure route, the deformation parameters of rock massif may be obtained by providing of in-situ tests in exploration gallery, e.g. plate static load tests. Driving of exploration galleries is usually thrown-over in Slovakia, in behalf of overwhelming cost-cutting worship. The results of geological investigation are then based only on laboratory tests, which consequently lead to inadequate characteristics of geotechnical parameters of rock massif. Thanks to advance in technical development of field-test apparatus there is a possibility to use pressuremeter and dilatometer tests as a relevant solution. The contribution brings an acquaintance with the new opportunities to detect deformation parameters on an example of dilatometer tests, provided for designed railway tunnel Kýčera.

  8. Thermal expansion of gadolinium in the vicinity of the Curie point. [270 to 320/sup 0/K, Curie point exponents

    Dolejsi, D.A.


    The c- and a-axis linear thermal expansivities of high purity single crystals of gadolinium were measured in the temperature range 270/sup 0/K to 320/sup 0/K. Length changes were translated to capacitance changes with a modified normal geometry 3-terminal capacitance dilatometer. An ac 3-terminal capacitance bridge was employed to measure nominal 10 pF capacitances to a precision of 10/sup -7/ pF, which corresponds to a relative length change sensitivity of 10/sup -10/. A 25 ohm platinum resistance thermometer was used to detect the dilatometer temperature to a precision of 10 with an ac resistance bridge. The c-axis expansivity was negative and had a large (approximately equal to 10/sup -4/ K/sup -1/) peak at 293.435/sup 0/K, while the a-axis expansivity was positive and had a smaller (approximately equal to 10/sup -5/ K/sup -1/) peak at 293.363/sup 0/K. The values of the Curie temperatures (T/sub c/'s) and critical point exponents for the c- and a-axis crystals were obtained from fitting power law equations to the expansivities.

  9. When is the strain in the meter the same as that in the rock?

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


    Borehole strainmeters are a valuable tool for monitoring crustal deformation and an important component of the Plate Boundary Observatory (PBO). One type, the dilatometer, measures the volumetric strain; three component strainmeters measure the dilatation and two in-plane shear strains. Borehole strainmeters are emplaced in porous fluid saturated rock. Pore-fluid flow induces strain, however there is no fluid exchange with the strainmeter. Thus, the dilatation measured by the strainmeter is the same as that in the rock only when the rock remains undrained. Assuming that the rock is homogeneous and isotropic, the instrumental dilatation Δ inst is given by Δ inst = C1 (Δ ∞ - C2 p∞ ), where Δ ∞ and p∞ are strain and pore pressure far from the borehole, and C1 and C2 depend on poroelastic rock properties; C1 = [{1-(1+ α )ν u}]/[{1-(1+ α )ν }], C2 = [{3(1+α )(ν u - ν )}]/[{2μ B(1+ν u)}], and ν , ν u are the drained and undrained Poisson's ratios, μ is shear modulus, B is Skempton's coefficient, and α measures the vertical strain sensitivity of the instrument. This predicts that increases in pore-pressure, due for example to rainfall, cause a contractional strain. A large rainfall event in south Iceland raised water levels by 1-2 meters (10 - 20 kPa). Assuming ν u = 0.33, ν = 0.25, B = 0.7, μ = 1010 Pa we predict contractions of order 180 nanostrain, in reasonable agreement with 4 of the 5 dilatometers in the area. Postseismic strain in the rock is expected to increase as the induced pore pressure gradients relax. However, a dilatometer ˜ 3 \\ km from a Mw 6.5 earthquake in the South Iceland Seismic Zone shows a postseismic strain change opposite in sign to the coseismic response. { Rice and Cleary, Rev. Geophys.,} [1976] give the solution for two-dimensional edge dislocation in a poroelastic medium. From their results and the theory described above, we predict that the dilatation recorded by a strainmeter will be time invariant! This despite

  10. Comparison of methods for physical determination of phase transformations temperatures

    S. Rusz


    Full Text Available Various physical methods for the determination of phase transformation temperatures were compared using C-Mn and C-Mn-V-Nb steels. The measurement using temperature scanner, variously located thermocouples, dilatometer, different thermal analysis (DTA and anisothermal plastometric test were completed. The specimens were heated to 1 323 K and 1 473 K in the case of the C-Mn-V-Nb microalloyed steel. The aim of the different heat treatment were to obtain different levels of precipitates’ dissolution. It was found that the better particles’ distribution and precipitation due to the cooling lead to the enlargement of the two-phase region in the material. The good agreement of result gained by used methods was achieved. We found that all used methods can be used for common steels, but the temperature scanner seems not to be precious enough for microalloyed steels.

  11. A first modeling of dynamic and static crustal strain field from near-field dilatation measurements: example of the 2013 M_w 6.2 Ruisui earthquake, Taiwan

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


    We analyze the high-resolution dilatation data for the October 2013 M_w 6.2 Ruisui, Taiwan, earthquake, which occurred at a distance of 15-20 km away from a Sacks-Evertson dilatometer network. Based on well-constrained source parameters (strike=217°, dip=48°, rake=49°), we propose a simple rupture model that explains the permanent static deformation and the dynamic vibrations at short period (˜ 3.5-4.5 s) for most of the four sites with less than 20 % of discrepancies. This study represents a first attempt of modeling simultaneously the dynamic and static crustal strain using dilatation data. The results illustrate the potential for strain recordings of high-frequency seismic waves in the near-field of an earthquake to add constraints on the properties of seismic sources.

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

    Prants, W.T.; Muller, D.T.; Orzechowski, L.G.; Feit, G.; Delima, S.A.; Camargo, N.H.A.; Gemelli, E., E-mail:, E-mail:, E-mail:, E-mail:, E-mail: [Universidade do Estado de Santa Catarina (UDESC), Joinville, SC (Brazil). Campus Universitario Prof. Avelino Marcante


    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)

  13. The Effect of Compositional Tailoring on the Thermal Expansion and Tribological Properties of PS300: A Solid Lubricant Composite Coating

    DellaCorte, C.; Fellenstein, J. A.


    This paper describes a research program in which the goal is to alter the thermal expansion coefficient of a composite solid lubricant coating, PS300, by compositional tailoring. PS300 is a plasma sprayed coating consisting of chrome oxide, silver and barium fluoride/calcium fluoride eutectic in NiCr binder. By adjusting the composition, the thermal expansion coefficient can be altered, and hence chosen, to more closely match a selected substrate preventing coating spallation at extreme temperatures. Thermal expansion coefficients (CTE) for a variety of compositions were measured from 25 to 800 C using a commercial dilatometer. The CTE's ranged from 7.0 to 13 x lO(exp -6)/deg C depending on the binder content. Subsequent tribological testing of a modified composition indicated that friction and wear properties were relatively insensitive to compositional tailoring.

  14. The Dependence of the Change in the Coefficient of Thermal Expansion of Graphite Fiber Reinforced Polyimide IM7-K3B on Microcracking due to Thermal Cycling

    Stewart, Melissa C.


    Composite IM7-K3B was subjected to a simulated high speed aircraft thermal environment to determine the effects of microcracking on the change in CTE. IM7-K3B is a graphite fiber reinforced polyimide laminate, manufactured by Dupont. The lay-up for the material was (0.90((Sub 3)(Sub s))). The specimens were placed in a laser-interferometric dilatometer to obtain thermal expansion measurements and were then repeatedly cycled between -65 F and 350 F up to 1000 cycles. After cycling they were scanned for microcracks at a magnification of 400x. The material was expected not to crack and to have a near zero CTE. Some microcracking did occur in all specimens and extensive microcracking occurred in one specimen. Further testing is required to determine how closely the CTE and microcracking are related.

  15. Low temperature thermal expansion measurements on optical materials.

    Browder, J S; Ballard, S S


    A three-terminal capacitance type dilatometer has been developed for investigating the thermal expansion of optical materials at low temperatures. The method is applicable when only small sample lengths (13 mm or less) are available. The thermal expansion coefficients of six polycrystalline materials (the Irtrans) and of one nonoxide glass have been determined in the range from room temperature down to about 60 K. Minute changes of the length of a sample produce a change of the spacing of a parallel plate capacitor with guard ring; the resulting change of capacitance is measured on a highly sensitive bridge. The expansion coefficients are then determined by relating the change of capacitance to the change of dimensions of the sample.

  16. Effects of Austenite Stabilization on the Onset of Martensite Transformation in T91 Steel

    Baoqun NING; Yongchang LIU; Qingzhi SHI; Zhiming GAO; Liushuan YANG


    The influences of thermal stabilization of austenitic on the onset temperature for a martensite transformation in T91 ferritic heat-resistant steel were studied by high-resolution differential dilatometer. The phase trans-formation kinetic information was obtained by adopting lever rule from the recorded dilatometric curves. The results show that an inverse stabilization, featured by the damage of "the atmosphere of carbon atoms" and the increase of the starting temperature for martensite transformation takes place when the T91 ferritic steel is isothermally treated above the Ms point, and it becomes strong with increasing the holding time. While the continued temperature for martensite transformation decreases gradually when isothermally holding at a temperature below Ms point. The observed inverse stabilization behavior could be attributed to the relatively high temperature of Ms point in the explored T91 ferritic heat-resistant steel.

  17. Using Colored Cullet for Making Beautiful Glassware

    Kim, Dong-Sang; Matyas, Josef


    Eight colored glasses from Fire and Light Originals (FLO) and three container cullet glasses were characterized for the viscosity, density, and thermal expansion, glass transition temperature, dilatometer softening temperature, color chromaticity, Fe(II)/Fe(total) redox ratio, and chemical composition. The results of the characterization were used to evaluate the options for the glass formulation development of colored glasses aimed at increasing the use of recycled container glass cullet. Out of several options considered, the possibility of using clear cullet for FLO’s Citrus colored glass was selected and investigated in this study. It was shown that it is possible to use clear cullet to produce Citrus glass at the cullet oxide ratio of 90 mass% and the final color can be adjusted by controlling the nitrate level and alkali concentrations. From the present study, recommendations for further development efforts are provided to increase the container cullet usage or to replace partially or entirely the clear cullet by the amber cullet.

  18. Study of Sm0.2Ce0.8O1.9 (SDC) electrolyte prepared by a simple modified solid-state method

    殷仕龙; 李梦楠; 曾燕伟; 李传明; 陈小卫; 叶祝鹏


    Sm0.2Ce0.8O1.9 (SDC) electrolyte was prepared by a modified solid state method at relatively low sintering temperatures without any sintering promoters. The phase composition and microstructure of the electrolytes were investigated by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) technologies. A relative density of SDC electrolyte sintered at 1300 ºC reached 97.3%and the mean SDC grain size was about 770 nm. Their ionic conductivity and thermal expansion coefficient were also measured by electrochemical workstation and dilatometer. The electrolyte attained a high conductivity of 5×10-2 S/cm at 800 ºC with an activation energy of 1.03 eV and a proper thermal expansion coefficient of 12.6×10-6 K-1.

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

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


    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

  20. Influence of Nanosized Silicon Carbide on Dimensional Stability of Al/SiC Nanocomposite

    S. M. Zebarjad


    Full Text Available This study concentrated on the role of particle size of silicon carbide (SiC on dimensional stability of aluminum. Three kinds of Al/SiC composite reinforced with different SiC particle sizes (25 μm, 5 μm, and 70 nm were produced using a high-energy ball mill. The standard samples were fabricated using powder metallurgy method. The samples were heated from room temperature up to 500∘C in a dilatometer at different heating rates, that is, 10, 30, 40, and 60∘C/min. The results showed that for all materials, there was an increase in length change as temperature increased and the temperature sensitivity of aluminum decreased in the presence of both micro- and nanosized silicon carbide. At the same condition, dimensional stability of Al/SiC nanocomposite was better than conventional Al/SiC composites.

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

    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)


    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. Camber Evolution and Stress Development of Porous Ceramic Bilayers During Co-Firing

    Ni, De Wei; Esposito, Vincenzo; Schmidt, Cristine Grings;


    Camber evolution and stress development during co-firing of asymmetric bilayer laminates, consisting of porous Ce0.9Gd0.1O1.95 gadolinium-doped cerium oxide (CGO) and La0.85Sr0.15MnO3 lanthanum strontium manganate (LSM)-CGO were investigated. Individual layer shrinkage was measured by optical...... dilatometer, and the uniaxial viscosities were determined as a function of layer density using a vertical sintering approach. The camber evolution in the bilayer laminates was recorded in situ during co-firing and it was found to correspond well with the one predicted by the theoretical model. The estimated...... sintering mismatch stress in co-fired CGO-LSM/CGO bilayer laminates was significantly lower than general sintering stresses expected for free sintering conditions. As a result, no co-firing defects were observed in the bilayer laminates, illustrating an acceptable sintering compatibility of the ceramic...

  3. Carbide Dissolution during Intercritical Austenitization in Bearing Steel

    LI Hui; MI Zhenli; ZHANG Xiaolei; TANG Di; WANG Yide


    In order to investigate the carbide dissolution mechanism of high carbon-chromium bearing steel during the intercritical austenitization, the database of TCFE7 of Thermo-calc and MOBFE of DICTRA software were used to calculate the elements diffusion kinetic and the evolution law of volume fraction of carbide. DIL805A dilatometer was used to simulate the intercritical heat treatment. The microstructure was observed by scanning electron microscopy(SEM), and the micro-hardness was tested. The experimental results indicate that the dissolution of carbide is composed of two stages:initial austenite growth governed by carbon diffusion which sharply moves up the micro-hardness of quenched martensite, and subsequent growth controlled by diffusion of Cr elements in M3C. The volume fraction of M3C decreases with the increasing holding time, and the metallographic analysis shows a great agreement with values calculated by software.

  4. Dilatometric examination of moulds with plaster binder

    M. Nadolski


    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.

  5. Hot Deformation Of 6xxx Series Aluminium Alloys

    Mrówka-Nowotnik G.


    Full Text Available The hot deformation behavior of the 6xxx aluminum alloys was investigated by compression tests in the temperature range 100°C-375°C and strain rate range 10−4s−1 and 4×10−4s−1 using dilatometer DIL 805 BÄHR Thermoanalyse equipped with accessory attachment deformation allows the process to execute thermoplastic in vacuum and inert gas atmosphere. Associated microstructural changes of characteristic states of examined alloys were studied by using the transmission electron microscope (TEM. The results show that the stress level decreases with increasing deformation temperature and deformation rate. And was also found that the activation energy Q strongly depends on both, the temperature and rate of deformation. The results of TEM observation showing that the dynamic flow softening is mainly as the result of dynamic recovery and recrystallization of 6xxx aluminium alloys.

  6. Use of solar furnaces. II - Thermophysical properties

    Suresh, D.; Charters, W. W. S.; Rohatgi, P. K.


    The various ways in which solar furnaces have been used to measure the high-temperature thermophysical properties of materials are reviewed, with attention given to the advantages and disadvantages of these furnaces. Thermal expansion experiments are seen as lacking accuracy. By introducing homogeneous heating methods, as well as precision dilatometers, this defect could be overcome. Solar furnaces must be designed so as to give larger focal areas of uniform flux density. Modifying the pulsed method so as to eliminate the requirement for homogeneity of the energy flux is thought desirable. It would also be worthwhile to design a suitable loading device to obviate complications arising out of elongation of the specimen during tests.

  7. Thin wall ductile and austempered iron castings

    E. Fraś


    Full Text Available It has been shown that it is possible to produce thin wall castings made of ductile iron with wall thickness in the range of 1.2 to 2.9 mm(without chills, cold laps and misruns. Thin wall ductile iron castings can be lighter (380 g than their substitutes made of aluminium alloys (580g. The kinetics of austenitising transformation was studied in unalloyed ductile iron. The advance of transformations during austenitising was monitored by measurement the fraction of martensite and also by dilatometic studies. It has been shown that in thin wall ductile iron castings austenitising at 880 oC for 20 minutes is adequate to obtain the austenite matrix at the end of the first stage of austempering heat treatment cycle.

  8. Apparent activation energy for densification of -Al2O3 powder at constant heating-rate sintering

    W Q Shao; S O Chen; D Li; H S Cao; Y C Zhang; S S Zhang


    The apparent activation energy for densification is a characteristic quantity that elucidates the fundamental diffusion mechanisms during the sintering process. 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 directly on the relative density. The apparent activation energy corresponding to lower relative density was higher than that corresponding to higher relative density. In addition, the value of the evaluated activation energy is different at the same density level when the Arrhenius plot involves different heating rates.

  9. Influence of Chemical Composition on Phase Transformation Temperature and Thermal Expansion Coefficient of Hot Work Die Steel

    XIE Hao-jie; WU Xiao-chun; MIN Yong-an


    On the basis of the uniform design method,six kinds of martensitie hot work die steels were designed.The phase transformation temperatures including Ac1,Ac3,and M,were measured by DIL805A quenching dilatometer.The influences of the main elements on phase transformation temperatures were analyzed by quadratic stepwise regression analysis,and three corresponding equations were obtained.These equations,in which the interactions of the elements were considered,showed more effectiveness than the traditional ones.In addition,the thermal expansion coefficients of these steels in annealed state and quenched state were also obtained during the tests.The influences of chemical composition and temperature on the thermal expansion coefficient were analyzed;the equations obtained Were verified by using several kinds of steels.The predicted values were in accordance with the results of the experiments.

  10. A first modeling of dynamic and static crustal strain field from near-field dilatation measurements: example of the 2013 M_w 6.2 Ruisui earthquake, Taiwan

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


    We analyze the high-resolution dilatation data for the October 2013 M_w 6.2 Ruisui, Taiwan, earthquake, which occurred at a distance of 15-20 km away from a Sacks-Evertson dilatometer network. Based on well-constrained source parameters (strike=217°, dip=48°, rake=49°), we propose a simple rupture model that explains the permanent static deformation and the dynamic vibrations at short period (˜ 3.5-4.5 s) for most of the four sites with less than 20 % of discrepancies. This study represents a first attempt of modeling simultaneously the dynamic and static crustal strain using dilatation data. The results illustrate the potential for strain recordings of high-frequency seismic waves in the near-field of an earthquake to add constraints on the properties of seismic sources.

  11. Thermodynamic Properties of Ternary Liquid Mixtures of 2-Pyrrolidinone with Aromatic Hydrocarbons

    Yadav, Jaibir S.; Sharma, Dimple; Sharma, Vinod Kumar


    Molar excess volumes, {V^E_{ijk}}, and speeds of sound, u ijk , of 2-pyrrolidinone (2-Py) ( i) + toluene ( j) + o-xylene or p-xylene ( k) ternary mixtures have been determined by using a dilatometer and interferometer as a function of composition at 308.15 K. The speeds of sound of ternary mixtures have been utilized to predict their excess isentropic compressibilities. The Redlich-Kister equation has been fitted to the molar excess volumes, {V^E_{ijk}}, and excess isentropic compressibilities, {left( {kappa _S^E}right)_{ijk}}, to predict ternary adjustable parameters and standard deviations. The observed data have been analyzed in terms of the Flory theory and the Sanchez and Lacombe theory.

  12. Excess Molar Volume of Binary Systems Containing Mesitylene

    Morávková, L.


    Full Text Available This paper presents a review of density measurements for binary systems containing 1,3,5-trimethylbenzene (mesitylene with a variety of organic compounds at atmospheric pressure. Literature data of the binary systems were divided into nine basic groups by the type of contained organic compound with mesitylene. The excess molar volumes calculated from the experimental density values have been compared with literature data. Densities were measured by a few experimental methods, namely using a pycnometer, a dilatometer or a commercial apparatus. The overview of the experimental data and shape of the excess molar volume curve versus mole fraction is presented in this paper. The excess molar volumes were correlated by Redlich–Kister equation. The standard deviations for fitting of excess molar volume versus mole fraction are compared. Found literature data cover a huge temperature range from (288.15 to 343.15 K.

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

    Bræstrup, Frantz Radzik; Kammer Hansen, Kent


    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...

  14. Analysis of borehole expansion and gallery tests in anisotropic rock masses

    Amadei, B.; Savage, W.Z.


    Closed-form solutions are used to show how rock anisotropy affects the variation of the modulus of deformation around the walls of a hole in which expansion tests are conducted. These tests include dilatometer and NX-jack tests in boreholes and gallery tests in tunnels. The effects of rock anisotropy on the modulus of deformation are shown for transversely isotropic and regularly jointed rock masses with planes of transverse isotropy or joint planes parallel or normal to the hole longitudinal axis for plane strain or plane stress condition. The closed-form solutions can also be used when determining the elastic properties of anisotropic rock masses (intact or regularly jointed) in situ. ?? 1991.

  15. Pearlitic Lamellae Spheroidisation During Austenitization and Subsequent Temperature Hold

    Hauserova D.


    Full Text Available Typical processing routes for bearing steels include a soft annealing stage. The purpose of this procedure is to obtain a microstructure containing globular carbides in ferritic matrix. A newly developed process called ASR (Accelerated Spheroidisation and Refinement cuts the carbide spheroidisation times several fold, producing considerably finer globular carbides than conventional soft annealing. Finer microstructure also leads to more homogeneous and finer structure after final hardening process. The present paper explores process of the accelerated spheroidisation (ASR in steel 100CrMnSi6-4 with initial pearlitic structure. Cementite lamellae morphology was observed in different stages of austenitization. The heat treatment was performed using induction heating in quenching dilatometer. There was analysed influence of austenitization temperature and austenitization time on spheroidisation. Hardness and carbide morphology was observed. Deep etching was used to reveal evolution of cementitic lamellae fragmentation. It is favourable process especially in induction treatment of small parts.

  16. Continuous Cooling Transformation Behavior and Kinetic Models of Transformations for an Ultra-Low Carbon Bainitic Steel

    ZHANG Zhi-min; CAI Qing-wu; YU Wei; LIXiao-lin; WANG Li-dong


    The aim was to investigate transformation behavior and transformation kinetics of an ultra-low carbon bai- nitic steel during continuous cooling. Continuous cooling transformation (CCT) curves of tested steel were measured by thermal dilatometer and metallographic structures at room temperature were observed by optical microscope. Then transformation kinetic equation of austenite to ferrite as well as austenite to bainite was established by analyzing the relationship of lnln]-l/(1--f)] and lnt in the kinetic equation on the basis of processed experimental data. Finally, the measured and calculated kinetic behaviors of the steel during continuous cooling were compared and growth pat- terns of transformed ferrite and bainite were analyzed. Results showed that calculated result was in reasonable agree- ment with the experimental data. It could be concluded that the growth modes of transformed ferrite and bainite were mainly one dimension as the Avrami exponents were between 1 and 2.

  17. Prediction of representative deformation modulus of longwall panel roof rock strata using Mamdani fuzzy system

    Mohammad Rezaei; Mostafa Asadizadeh; Abbas Majdi; Mohammad Farouq Hossaini


    Deformation modulus is the important parameter in stability analysis of tunnels, dams and mining struc-tures. In this paper, two predictive models including Mamdani fuzzy system (MFS) and multivariable regression analysis (MVRA) were developed to predict deformation modulus based on data obtained from dilatometer tests carried out in Bakhtiary dam site and additional data collected from longwall coal mines. Models inputs were considered to be rock quality designation, overburden height, weathering, unconfined compressive strength, bedding inclination to core axis, joint roughness coefficient and fill thickness. To control the models performance, calculating indices such as root mean square error (RMSE), variance account for (VAF) and determination coefficient (R2) were used. The MFS results show the significant prediction accuracy along with high performance compared to MVRA results. Finally, the sensitivity analysis of MFS results shows that the most and the least effective parameters on deformation modulus are weathering and overburden height, respectively.

  18. Densification studies of silicon carbide-based ceramics with yttria, silica and alumina as sintering additives

    J. Marchi


    Full Text Available Silicon carbide has been extensively used in structural applications, especially at high temperatures. In this work, Y2O3, Al2O3 and SiO2 were added to beta-SiC in order to obtain highly dense ceramics. Sintering was conducted in a dilatometer and in a graphite resistance furnace and the densification behaviour was studied. Sintered samples were characterised by density measurements, the crystalline phases were identified by X-ray diffraction. Microstructural observation of polished and polished/etched samples was carried out with help of scanning electron microscopy. Silicon carbide ceramics with more than 90% of the theoretical density were obtained by pressureless sintering if a suitable proportion of the additives is used.

  19. Uncertainty evaluation of the thermal expansion of simulated fuel

    Park, Chang Je; Kang, Kweon Ho; Song, Kee Chan [Korea Atomic Energy Research Institute, 150 Dukjin-dong, Yuseung-gu, Daejon 305-353 (Korea, Republic of)


    Thermal expansions of simulated fuel (SS1) are measured by using a dilatometer (DIL402C) from room temperature to 1900K. The main procedure of an uncertainty evaluation was followed by the strategy of the UO{sub 2} fuel. There exist uncertainties in the measurement, which should be quantified based on statistics. Referring to the ISO (International Organization for Standardization) guide, the uncertainties of the thermal expansion are quantified in three parts: the initial length, the length variation, and the system calibration factor. Each part is divided into two types. The A type uncertainty is derived from the statistical iterative measurement of an uncertainty and the B type uncertainty comes from a non-statistical uncertainty including a calibration and test reports. For the uncertainty evaluation, the digital calipers had been calibrated by the KOLAS (Korea Laboratory Accreditation Scheme) to obtain not only the calibration values but also the type B uncertainty. The whole system, the dilatometer (DIL402C), is composed of many complex sub-systems and in fact it is difficult to consider all the uncertainties of sub-systems. Thus, a calibration of the system was performed with a standard material (Al{sub 2}O{sub 3}), which is provided by NETZSCH. From the above standard uncertainties, the combined standard uncertainties were calculated by using the law of a propagation of an uncertainty. Finally, the expanded uncertainty was calculated by using the effective degree of freedom and the t-distribution for a given confidence level. The uncertainty of the thermal expansion for a simulated fuel was also compared with those of UO{sub 2} fuel. (author)

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



    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

  1. Properties of Liquid Plutonium

    Freibert, Franz J. [Los Alamos National Laboratory; Mitchell, Jeremy N. [Los Alamos National Laboratory; Schwartz, Daniel S. [Los Alamos National Laboratory; Saleh, Tarik A. [Los Alamos National Laboratory; Migliori, Albert [Los Alamos National Laboratory


    Unalloyed polycrystalline Pu displays extreme thermal expansion behavior, i.e., {alpha} {yields} {beta} {yields} {gamma} {yields} {delta} increases by 25% in volume and {delta} {yields} {var_epsilon} {yields} liquid decreases by 4.5% in volume. Thus, making it difficult to measure density into the liquid state. Dilatometer outfitted with CaF molten metal cell offers a proven capability to measure thermal expansion in molten metals, but has yet to be proven for Pu. Historic data from the liquid nuclear fuels program will prove extremely useful as a guide to future measurements. 3.3at% Ga changes Pu molten metal properties: 50% increase in viscosity and {approx}3% decrease in density. Fe may decrease the density by a small amount assuming an averaging of densities for Pu-Ga and Pu-Fe liquids. More recent Boivineau (2009) work needs some interpretation, but technique is being employed in (U,Pu)O{sub 2} nuclear fuels program (Pu Futures, 2012).

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

    Akihiro Takezawa


    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.

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

    Dr. Manish Metha; Dr. Tom Oakwood


    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.

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

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


    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.

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

    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


    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)

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

    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)


    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.

  7. Improvement of the Dimensional Stability of Powder Injection Molded Compacts by Adding Swelling Inhibitor into the Debinding Solvent

    Fan, Yang-Liang; Hwang, Kuen-Shyang; Su, Shao-Chin


    Defects are frequently found in powder injection molded (PIM) compacts during solvent debinding due to the swelling of the binders. This problem can be alleviated by adjusting the composition of the debinding solvent. In this study, 10 vol pct swelling inhibitors were added into heptane, and the in-situ amounts of swelling and sagging of the specimen in the solvent were recorded using a noncontacting laser dilatometer. The results show that the addition of ethanol, 2-propanol, 1-butanol, and 1-pentanol reduced the amounts of swelling by 31, 21, 17, and 11 pct, respectively. This was because the small molecule alcohols, which do not dissolve paraffin wax (PW) or stearic acid (SA) in the binder system, could diffuse easily into the specimen and increased the portion of the swelling inhibitor inside. The amount of the extracted PW and SA also decreased, but only by 8.3, 6.1, 4.3, and 2.4 pct, respectively. The solubility parameters of 1-bromopropane (n-PB) and ethyl acetate (EA) are between those of heptane and alcohols, and they also yielded a slight reduction in the amounts of swelling by 6 and 11 pct, respectively. These results suggest that to reduce defects caused by binder swelling during solvent debinding, alcohols with high solubility parameters can be added into heptane without sacrificing significantly on the debinding rate.

  8. The Effect of Thermo-Mechanical Treatment on Structure of Ultrahigh Carbon PM Steel

    Nikiel, Piotr; Szczepanik, Stefan; Skrzypek, Stanisław Jan; Rogal, Łukasz


    The effects of thermo-mechanical treatment on selected properties related to the structure of Fe-0.85Mo-0.65i-1.4C powder metallurgy (PM) steel are reported. Three kinds of initial microstructure of specimens, i.e., pearlite + ferrite + cementite, martensite + retained austenite and α + spheroidized cementite were examined. Processing was carried out on a plastometer-dilatometer Bähr machine by compression cylindrical specimens at 775 °C at a strain rate of 0.001 s-1. X-ray diffraction was carried out with symmetrical Bragg-Brentano and grazing incident angle methods on a D8-Advance diffractometer with filtered radiation of cobalt CoK α . The following features were determined: texture, density of dislocations, density of vacancies, lattice parameter of Fe α and mean size of crystallites. Significant differences in structure were observed, especially in quenched specimen, as a result of the thermo-mechanical treatment. Regardless of initial state of the specimens, the determined properties were on a similar level. Crystallite size was in the range 97-106 nm, crystallite texture (I{200}/I{110}) × 10 = 1.15-1.62 and density of vacancies I{110}/I{220} = 7.06-7.52.

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

    Ma, X.P.; Wang, L.J. [Key Laboratory for Anisotropy and Texture of Materials, Northeastern University, Shenyang 110004 (China); Liu, C.M., E-mail: [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)


    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.

  10. Dilatometric investigations of phase transformations at heating and cooling of hardened, unalloyed, high-carbon steels

    J. Pacyna


    Full Text Available Purpose: The reason for writing this paper was to describe the kinetics of phase transformations during continuous heating from hardened state and subsequent cooling of unalloyed high carbon steel.Design/methodology/approach: Dilatometric investigations were performed using a DT 1000 dilatometer of a French company Adamel. Samples after quenching and quenching and sub-quenching in liquid nitrogen (-196 °C were heated up 700 °C at the rate of 0.05 °C/s and subsequent cooled to room temperature at the rate of 0.05 °C/s.Findings: Regardless of heating the hardened high-carbon steel to 700 °C, a small fraction of the retained austenite remained in its structure, and was changing into fresh martensite only during cooling in the temperature range: 280°C-170°C.Research limitations/implications: Schematic presentation of the differential curve of tempering of the hardened high-carbon, unalloyed steel illustrating the phase transformations occurring during heating from hardened state.Practical implications: An observation, that a small fraction of the retained austenite remained in the structure of tempered high-carbon steel, indicates that even unalloyed steel should be tempered two times.Originality/value: Detailed descriptions of kinetics phase transformations during heating from hardened state of unalloyed high carbon steel.

  11. Study on Heat Treatment Process for Blade Castings of Hydraulic Turbine Set in Three Gorges Project%三峡水轮机组叶片铸件热处理工艺研究

    高扬; 董晓亮


    以三峡水轮机组叶片铸件为研究对象,对其热处理工艺进行了研究。采用热膨胀仪进行特征相变点的测定,通过热处理试验确定热处理工艺参数对机械性能的影响关系,提出了叶片铸件最佳热处理工艺路线及工艺参数,并应用于实际生产,生产出的叶片铸件各项性能指标均满足设计要求。%The heat treatment process for the blade castings is studied by taking samples of these blade castings of hydraulic turbine in Three Gorges Project. The feature transition points are measured by thermal dilatometer and the effect of parameters of heat treatment process on me-chanical properties are confirmed by heat treatment test. After that the optimal heat treatment pro-cess and technological parameters for treating blade castings are proposed. When the new process and technological parameters are put into operation, all kinds of properties of the blade castings produced by application of the process and parameters can meet the design requirements.

  12. Hot Stamping of Boron Steel Using Partition Heating for Tailored Properties: Experimental Trials and Numerical Analysis

    Mu, Yanhong; Wang, Baoyu; Zhou, Jing; Huang, Xu; Li, Xuetao


    Hot-stamped components with tailored properties are becoming popular for their better performance in collision. In this article, an M-shaped part with varying properties was formed by hot stamping using partition heating. Different soaking temperatures induce different austenite fractions at the different regions of the blank, resulting in the partitioned microstructure and mechanical properties in a single part. In the high-temperature region, the average tensile strength and elongation are 1565 MPa and 8.65 pct, respectively, and the average tensile strength and elongation are 626 MPa and 24.37 pct, respectively, in the low-temperature region. A finite element model of hot stamping using partition heating was established based on the relationship of austenite fraction with heating temperature determined by the dilatometer test and the stress-strain curve of 22MnB5 with different austenite fractions acquired from the hot tensile test.The differences of temperature, thickness, and Vickers hardness in different zones of the M-shaped part during forming and quenching stages were analyzed. The effects of hot stamping parameters, such as stamping velocity and heating temperature, on the forming and mechanical properties of the tailored M-shaped part were investigated, providing theoretical guidance for the production of tailored hot-stamped components using partition heating.

  13. Shock and Detonation Physics at Los Alamos National Laboratory

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


    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.

  14. Effects of Isothermal Aging on Microstructure Evolution, Hardness and Wear Properties of Wrought Co-Cr-Mo Alloy

    Khaimanee, P.; Choungthong, P.; Uthaisangsuk, V.


    In this work, effects of isothermal aging on phase transformation, microstructure evolution, hardness and wear resistance of the wrought Co-Cr-Mo alloy with low carbon content were investigated. Initially, temperature range of FCC to HCP phase transformation of the alloy was determined by a dilatometer test. Then, aging at the temperature of 850 °C for different holding times with subsequent water quenching was carried out. Metallography examination, x-ray diffraction analysis, microhardness test and wear test were performed for Co-Cr-Mo alloy specimens after the isothermal aging. It was found that the FCC to HCP phase transformation occurred in the temperature range between 700 and 970 °C. During the aging treatment, phase fraction of the HCP martensite increased with longer aging time. The FCC to HCP phase transformation was completed after 12 h, because very fine lamellae in different orientations thoroughly dispersed within FCC grains were observed. These lamella structures could be well correlated with formation of the HCP martensite. Small amounts of carbides were found at grain boundaries and grain intersections in the samples aged for 6 and 12 h. In addition, by longer aging time, the average grain size of the aged alloy became a little bit larger, while the hardness noticeably increased. For the examined Co-Cr-Mo alloy, higher amount of the emerged HCP martensitic phase led to the increased hardness value, but reduced friction coefficient and wear rate.

  15. Properties of a New Dental Photocurable Matrix Resin with Low Shrinkage

    FU Jing; JIA Fang; XU Haiping; JI Baohui; LIU Xiaoqing


    In order to reduce the amount of volumetric shrinkage that occurs in dental composites as a result of curing, a new kind of dental matrix resin combining bisphenol-S-bis(3-meth acry late-2-hydroxy propyl)ether(BisS-GMA) with the expanding monomer unsaturated spiro orthoesters 2-methylene-1, 4, 6-trispiro[4, 4] nonane (SOE) was prepared, with triethylene glycol dimethacrylate (TEGDMA) as diluent. CQ (camphorquinone) of 1wt% and DMAEMA (2-(dimethylamino) ethyl meth acrylate) of 2wt% were used as photoinitiation system to initiate the copolymerization of the matrix resins. The performance including volumetric shrinkage, degree of conversion and condition of the ring-opening reaction of SOE, as well as curing time and the tensile bond strength were investigated respectively by the dilatometer, Fourier transfer infrared, the universal testing machine, and so on.The ring-opening polymerization of SOE occurred. Meanwhile, the obtain copolymers were crosslinked. The matrix resin containing BisS-GMA and SOE showed a reduced amount of volumetric shrinkage at 1.52%, which is a promising strategy for obtaining a polymer with a low amount of volumetric shrinkage. Furthermore, the other properties were not compromised.

  16. Thermophysical Properties of Manganin (Cu86Mn12Ni2) in the Solid and Liquid State

    Schmon, A.; Aziz, K.; Luckabauer, M.; Pottlacher, G.


    Manganin is the trademark name of the alloy Cu86Mn12Ni2. Despite its frequent usage in manufacturing processes, literature data are scarce particularly at higher temperatures. This work presents a set of thermophysical data of this alloy in a temperature range above its classic area of application up to the end of its liquid phase. For investigating the alloy, four examination setups were employed. Using differential thermal analysis, solidus and liquidus temperatures were obtained. In the solid phase, the electrical resistivity as a function of temperature was determined by a four-point probe positioned in a furnace. Thermal expansion was measured with a high-resolution two-beam laser dilatometer based on Michelson-interferometry and thereby density was calculated. The liquid state was investigated using a s-ohmic-pulse-heating setup. Wire-shaped specimens were resistively volume heated as part of an electrical discharge circuit. Measured quantities were the current through the specimen, the voltage drop along the specimen, the surface radiance by a pyrometer, and the thermal expansion with an adapted CCD camera system. On the basis of these measurements, temperature-dependent thermophysical properties of enthalpy, isobaric heat capacity, electrical resistivity, and density are obtained. Additionally the thermal conductivity and thermal diffusivity are estimated in the high-temperature range applying the Wiedemann-Franz law.

  17. Study of hydroxyapatite behaviour during sintering of 316L steel

    A. Szewczyk-Nykiel


    Full Text Available 316L stainless steel – hydroxyapatite composite biomaterials with different hydroxyapatite weight fraction in the composite wereinvestigated. Hydroxyapatite (HAp – Ca10(PO46(OH2 is well known biomaterial. HAp reveals excellent chemical and biological affinitywith bony tissues. On the other hand hydroxyapatite shows low mechanical properties. The combination of very good biocompatibility of hydroxyapatite and high mechanical properties of stainless steel seems to be a good solution. In presented research natural originhydroxyapatite and 316L austenitic stainless steel were used. In this work, metal-ceramics composites were fabricated by the powdermetallurgy technology (involving pressing and sintering process. Sintering was carried out at 1250oC in hydrogen atmosphere. Thedensity, porosity and hardness were investigated. Metallographic microscope and SEM were carried out in order to investigate themicrostructure. The horizontal NETZSCH DIL 402E dilatometer was used to evaluate the dimensional changes and phenomena occurringduring sintering. The research displayed that physical properties of sintered 316L-HAp composites decrease with increase ofhydroxyapatite content. Microstructure of investigated composites consists of austenitic and probably inclusions of hydroxyapatite andheterogeneous eutectic occurring on the grain boundaries. It was shown that amount of hydroxyapatite in the powder mixtures influencethe dimensional changes occurring during sintering.

  18. Effect of previous phase formation on densification and microstructure of aluminum titanate; Efeito da pre-formacao de fase na densificacao e microestrutura do titanato de aluminio

    Guedes e Silva, C.C.; Zaninelli, G.; Genova, L.A., E-mail: [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Carvalho, F.M.S. [Universidade de Sao Paulo (IGC/USP), Sao Paulo, SP (Brazil). Instituto de Geociencias


    Aluminum titanate based ceramics are potential candidates for many industrial applications mainly due to their low coefficient of thermal expansion and high thermal shock resistance. However, these ceramics are susceptible to phase dissociation in temperature range between 1100 and 1300 deg C, with consequent deterioration of properties. In this paper, it was assessed the effect of previous formation of Al{sub 2}TiO{sub 5}, obtained by calcination and subsequent grinding of equimolar mixtures of Al{sub 2}O{sub 3} and TiO{sub 2}, containing MgO and SiO{sub 2}, additives which promote Al{sub 2}TiO{sub 5} stabilization. Compacted samples from calcinated and non-calcinated powders were evaluated considering densification, formed crystalline phases, as well as grains size and morphology, by means of dilatometer studies, sintering treatments, X-ray diffraction and scanning electron microscopy. The effect of previous formation of Al{sub 2}TiO{sub 5} was associated with the properties and obtained features. (author)

  19. Simultaneous measurement of magnetization and magnetostriction in 50 T pulsed high magnetic fields.

    Doerr, M; Lorenz, W; Neupert, T; Loewenhaupt, M; Kozlova, N V; Freudenberger, J; Bartkowiak, M; Kampert, E; Rotter, M


    To simultaneously perform magnetization and magnetostriction measurements in high magnetic fields, a miniaturized device was developed that combines an inductive magnetometer with a capacitive dilatometer and, therefore, it is called "dilamagmeter." This combination of magnetic and magnetoelastic investigations is a new step to a complex understanding of solid state properties. The whole system can be mounted in a 12 mm clear bore of any cryostat usually used in nondestructive pulsed high field magnets. The sensitivity of both methods is about 10(-5) A m(2) for magnetization and 10(-5) relative changes in length for striction measurements. Measurements on a GdSi single crystal, which are corrected by the background signal of the experimental setup, agree well with the results of steady field experiments. All test measurements, which are up until now performed in the temperature range of 4-100 K, confirm the perfect usability and high stability in pulsed fields up to 50 T with a pulse duration of 10 ms.

  20. Progress on glass ceramic ZERODUR enabling nanometer precision

    Jedamzik, Ralf; Kunisch, Clemens; Nieder, Johannes; Weber, Peter; Westerhoff, Thomas


    The Semiconductor Industry is making continuous progress in shrinking feature size developing technologies and process to achieve glass ceramic ZERODUR® is a well-established material in critical components of microlithography wafer stepper and offered with an extremely low coefficient of thermal expansion, the tightest tolerance available on market. SCHOTT is continuously improving manufacturing processes and it's method to measure and characterize the CTE behavior of ZERODUR®. This paper is focusing on the "Advanced Dilatometer" for determination of the CTE developed at SCHOTT in the recent years and introduced into production in Q1 2015. The achievement for improving the absolute CTE measurement accuracy and the reproducibility are described in detail. Those achievements are compared to the CTE measurement accuracy reported by the Physikalische Technische Bundesanstalt (PTB), the National Metrology Institute of Germany. The CTE homogeneity is of highest importance to achieve nanometer precision on larger scales. Additionally, the paper presents data on the short scale CTE homogeneity and its improvement in the last two years. The data presented in this paper will explain the capability of ZERODUR® to enable the extreme precision required for future generation of lithography equipment and processes.

  1. High Precision CTE-Measurement of SiC-100 for Cryogenic Space-Telescopes

    Enya, K; Onaka, T; Nakagawa, T; Kaneda, H; Hirabayashi, M; Toulemont, Y; Castel, D; Kanai, Y; Fujishiro, N


    We present the results of high precision measurements of the thermal expansion of the sintered SiC, SiC-100, intended for use in cryogenic space-telescopes, in which minimization of thermal deformation of the mirror is critical and precise information of the thermal expansion is needed for the telescope design. The temperature range of the measurements extends from room temperature down to $\\sim$ 10 K. Three samples, #1, #2, and #3 were manufactured from blocks of SiC produced in different lots. The thermal expansion of the samples was measured with a cryogenic dilatometer, consisting of a laser interferometer, a cryostat, and a mechanical cooler. The typical thermal expansion curve is presented using the 8th order polynomial of the temperature. For the three samples, the coefficients of thermal expansion (CTE), $\\bar{\\alpha}_{#1}$, $\\bar{\\alpha}_{#2}$, and $\\bar{\\alpha}_{#3}$ were derived for temperatures between 293 K and 10 K. The average and the dispersion (1 $\\sigma$ rms) of these three CTEs are 0.816 an...

  2. Application of High-Temperature Extrinsic Fabry-Perot Interferometer Strain Sensor

    Piazza, Anthony


    In this presentation to the NASA Aeronautics Sensor Working Group the application of a strain sensor is outlined. The high-temperature extrinsic Fabry-Perot interferometer (EFPI) strain sensor was developed due to a need for robust strain sensors that operate accurately and reliably beyond 1800 F. Specifically, the new strain sensor would provide data for validating finite element models and thermal-structural analyses. Sensor attachment techniques were also developed to improve methods of handling and protecting the fragile sensors during the harsh installation process. It was determined that thermal sprayed attachments are preferable even though cements are simpler to apply as cements are more prone to bond failure and are often corrosive. Previous thermal/mechanical cantilever beam testing of EFPI yielded very little change to 1200 F, with excellent correlation with SG to 550 F. Current combined thermal/mechanical loading for sensitivity testing is accomplished by a furnace/cantilever beam loading system. Dilatometer testing has can also be used in sensor characterization to evaluate bond integrity, evaluate sensitivity and accuracy and to evaluate sensor-to-sensor scatter, repeatability, hysteresis and drift. Future fiber optic testing will examine single-mode silica EFPIs in a combined thermal/mechanical load fixture on C-C and C-SiC substrates, develop a multi-mode Sapphire strain-sensor, test and evaluate high-temperature fiber Bragg Gratings for use as strain and temperature sensors and attach and evaluate a high-temperature heat flux gauge.

  3. 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

    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)


    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)

  4. Effect of Copper and Nickel on the Transformation Kinetics of Austempered Ductile Iron

    Górny, Marcin; Tyrała, Edward; Lopez, Hugo


    The kinetics of reaction occurring during the austempering treatment of ductile iron (DI) containing different additions of Cu and Ni was investigated in this work. DI bars were heat treated in an instrumented dilatometer in order to follow the exhibited transformation kinetics. The dilatometric results indicated that the addition of Cu alone did not have a significant effect on the incubation times for the austempering transformation. Also, the addition of both, Cu and Ni resulted in a significant effect on reducing the transformation rates. It was found that the austempering process is characterized by two clearly distinguished transformation stages. In the initial stage, the addition of Cu, and to a greater extent, additions of both Cu and Ni led to reductions in the transformation rates shifting the maximum transformation rate values toward longer times. The outcome of this work indicates that during the first stage of austempering, nucleation of the ferrite plates occurs via a diffusionless mechanism while their growth is diffusion controlled. Moreover, after the maximum in the transformation rate has been reached, the growth of ferrite plates becomes dominant with the rate-limiting step becoming the diffusion of C into the surrounding austenite. A qualitative model for the austempering transformation is proposed in this work to account for the experimental observations.

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

    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


    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...

  6. Dilatometric studies of (SiO2-RE2O3-Al2O3 silicon carbide ceramics

    Juliana Marchi


    Full Text Available Silicon carbide is an important structural ceramic and finds applications as abrasives, as a refractory and in automotive engine components. This material can attain high densities during liquid phase sintering if suitable additives are used. Silicon carbides containing silica, alumina and rare earth oxides have suitable characteristics to promote liquid phase sintering. In this paper, the sintering behavior of silicon carbide ceramics with additives based on the (SiO2-RE2O3-Al2O3 system (RE = Y, Dy has been studied. Samples with different compositions and containing 90 vol.% SiC were sintered in a dilatometer at 1950 °C/1h and in a graphite resistance furnace from 1500 °C/1h up to 1950 °C/1h. The shrinkage behavior as a function of rare earth oxide used and additive composition was also studied. The sintered materials were characterized by density and weight loss measurements. The crystalline phases were identified by X-ray diffraction analysis. The sintering kinetics of these materials can be related to the formation of secondary crystalline phases.

  7. Investigation of Hot Deformation Behavior of Duplex Stainless Steel Grade 2507

    Kingklang, Saranya; Uthaisangsuk, Vitoon


    Recently, duplex stainless steels (DSSs) are being increasingly employed in chemical, petro-chemical, nuclear, and energy industries due to the excellent combination of high strength and corrosion resistance. Better understanding of deformation behavior and microstructure evolution of the material under hot working process is significant for achieving desired mechanical properties. In this work, plastic flow curves and microstructure development of the DSS grade 2507 were investigated. Cylindrical specimens were subjected to hot compression tests for different elevated temperatures and strain rates by a deformation dilatometer. It was found that stress-strain responses of the examined steel strongly depended on the forming rate and temperature. The flow stresses increased with higher strain rates and lower temperatures. Subsequently, predictions of the obtained stress-strain curves were done according to the Zener-Hollomon equation. Determination of material parameters for the constitutive model was presented. It was shown that the calculated flow curves agreed well with the experimental results. Additionally, metallographic examinations of hot compressed samples were performed by optical microscope using color tint etching. Area based phase fractions of the existing phases were determined for each forming condition. Hardness of the specimens was measured and discussed with the resulted microstructures. The proposed flow stress model can be used to design and optimize manufacturing process at elevated temperatures for the DSS.

  8. Influence of the filler content on the thermal expansion behavior of an epoxy matrix particulate composite

    Tognana, S. [IFIMAT - Universidad Nacional del Centro de la Provincia de Buenos Aires, Pinto 399, B7000GHG Tandil (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (Argentina); Salgueiro, W. [IFIMAT - Universidad Nacional del Centro de la Provincia de Buenos Aires, Pinto 399, B7000GHG Tandil (Argentina); Somoza, A. [IFIMAT - Universidad Nacional del Centro de la Provincia de Buenos Aires, Pinto 399, B7000GHG Tandil (Argentina); Comision de Investigaciones Cientificas de la Provincia de Buenos Aires (Argentina)], E-mail:; Pomarico, J.A.; Ranea-Sandoval, H.F. [Consejo Nacional de Investigaciones Cientificas y Tecnicas (Argentina); IFAS - Universidad Nacional del Centro de la Provincia de Buenos Aires, Pinto 399, B7000GHG Tandil (Argentina)


    The thermal expansion behavior of epoxy matrix particulate composites prepared with different volumetric filler contents ({phi}) up to 25 vol.% was studied. Using a very simple absolute optical dilatometer developed in our laboratory, the coefficients of thermal expansion (CTE) for pure epoxy resin matrix and the composites in the glassy and rubbery states (293 K {<=} T {<=} 493 K) were obtained. For the matrix, the CTE obtained in the two states are in good agreement with those reported. For composites the results are discussed into the frame of different approaches using well-known mechanical models. In the glassy state, the CTE behavior could be well described by the upper bound of the Hashin-Shtrikman model. In the rubbery state it was necessary to evaluate the contribution of the average volume of nanoholes in the epoxy matrix as a consequence of the addition of particles. To this aim, using positron annihilation lifetime spectroscopy, the dependence of the average volume of nanoholes with {phi} was measured.

  9. A concept for non-invasive temperature measurement during injection moulding processes

    Hopmann, Christian; Spekowius, Marcel, E-mail:; Wipperfürth, Jens; Schöngart, Maximilian, E-mail: [Institute of Plastics Processing (IKV), RWTH Aachen University Pontstr. 49, 52062 Aachen (Germany)


    Current models of the injection moulding process insufficiently consider the thermal interactions between melt, solidified material and the mould. A detailed description requires a deep understanding of the underlying processes and a precise observation of the temperature. Because todays measurement concepts do not allow a non-invasive analysis it is necessary to find new measurement techniques for temperature measurements during the manufacturing process. In this work we present the idea of a set up for a tomographic ultrasound measurement of the temperature field inside a plastics melt. The goal is to identify a concept that can be installed on a specialized mould for the injection moulding process. The challenges are discussed and the design of a prototype is shown. Special attention is given to the spatial arrangement of the sensors. Besides the design of a measurement set up a reconstruction strategy for the ultrasound signals is required. We present an approach in which an image processing algorithm can be used to calculate a temperature distribution from the ultrasound scans. We discuss a reconstruction strategy in which the ultrasound signals are converted into a spartial temperature distribution by using pvT curves that are obtained by dilatometer measurements.

  10. Polymer-assisted co-precipitation route for the synthesis of Al$_2$O$_3$–13% TiO$_2$ nanocomposite



    The present investigation reveals the effect of processing parameters on the properties of alumina–titania (Al$_2$O$_3$–TiO$_2$) nanocomposites. A polymer-assisted (Pluronic P123 triblock co-polymer) co-precipitation route has been employed to synthesize Al$_2$O$_3$–TiO$_2$ nanoparticles. As a surfactant, pluronic P123 polymer exhibits hydrophobic as well as the hydrophilic nature simultaneously which detains the agglomeration and hence the nano size particle have been obtained. Effect of surfactant concentration on morphology and particle size of product has also been investigated. Thermal behaviour of the prepared powder samples have been studied using differential scanning calorimeter/thermal gravimetric analysis and dilatometer. Formation of aluminium-titanate (Al$_2$TiO$_5$) phase has been confirmed using X-ray diffraction analysis. It has been observed by field emission scanning electron microscopy analysis that the particle size reduced effectively (below 100 nm) when polymer-assisted co-precipitation route is used instead of the simple co-precipitation technique. A highly dense microstructure of sintered samples has been obtained, driven by reduced particle size.

  11. Investigation of Hot Deformation Behavior of Duplex Stainless Steel Grade 2507

    Kingklang, Saranya; Uthaisangsuk, Vitoon


    Recently, duplex stainless steels (DSSs) are being increasingly employed in chemical, petro-chemical, nuclear, and energy industries due to the excellent combination of high strength and corrosion resistance. Better understanding of deformation behavior and microstructure evolution of the material under hot working process is significant for achieving desired mechanical properties. In this work, plastic flow curves and microstructure development of the DSS grade 2507 were investigated. Cylindrical specimens were subjected to hot compression tests for different elevated temperatures and strain rates by a deformation dilatometer. It was found that stress-strain responses of the examined steel strongly depended on the forming rate and temperature. The flow stresses increased with higher strain rates and lower temperatures. Subsequently, predictions of the obtained stress-strain curves were done according to the Zener-Hollomon equation. Determination of material parameters for the constitutive model was presented. It was shown that the calculated flow curves agreed well with the experimental results. Additionally, metallographic examinations of hot compressed samples were performed by optical microscope using color tint etching. Area based phase fractions of the existing phases were determined for each forming condition. Hardness of the specimens was measured and discussed with the resulted microstructures. The proposed flow stress model can be used to design and optimize manufacturing process at elevated temperatures for the DSS.

  12. Single-contact pressure solution creep on calcite monocrystals

    Zubtsov, Sergei; Gratier, Jean-Pierre; Dysthe, Dag; Traskine, Vladimir


    Pressure solution creep rates and interface structures have been measured by two methods on calcite single crystals. In the first kind of experiments, calcite monocrystals were indented at 40 degrees C for six weeks using ceramic indenters under stresses in the 50-200 MPa range in a saturated solution of calcite and in a calcite-saturated aqueous solution of NH4Cl. The deformation (depth of the hole below the indenter) is measured ex-situ at the end of the experiment. In the second type of experiment, calcite monocrystals were indented by spherical glass indenters for 200 hours under stresses in the 0-100 MPa range at room temperature in a saturated aqueous solution of calcite. The displacement of the indenter was continuously recorded using a specially constructed differential dilatometer. The experiments conducted in a calcite-saturated aqueous solution of NH4Cl show an enhanced indentation rate owing to the fairly high solubility of calcite in this solution. In contrast, the experiments conducted in a calc...

  13. Cryogenic coefficient of thermal expansion measurements of type 440 and 630 stainless steel

    Cease, H.; Alvarez, M.; Flaugher, B.; Montes, J.


    The Dark Energy Camera is now installed on the Blanco 4m telescope at the Cerro Tololo Inter-American Observatory in Chile. The camera is cooled to 170K using a closed loop two-phase liquid nitrogen system. A submerged centrifugal pump is used to circulate the liquid from the base of the telescope to the camera in the prime focus cage. As part of the pump maintenance schedule, the rotor shaft bearings are periodically replaced. Common bearing and shaft materials are type 440 and 630 (17-4 PH) stainless steel. The coefficient of thermal expansion of the materials used is needed to predict the shaft and bearing housing dimensional changes at the 77K pump operating temperature. The thermal expansion from room temperature to 77K of type 440 and 630 stainless steel is presented . Measurements are performed using the ASTM E228 standard with a quartz push-rod dilatometer test stand. Aluminum 6061-T6 is used to calibrate the test stand.

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

    Hofer, Christina, E-mail: [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)


    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.


    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.


    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.

  16. Magnetoelasticity of (Lu{sub 0.8}Ce{sub 0.2}){sub 2}Fe{sub 17} intermetallic compound

    Andreev, A.V. [Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, Prague, 18221 (Czech Republic)], E-mail:; Koyama, K. [HFLSM, Institute for Materials Research, Tohoku University, Katahira 2-1-1, Sendai, 980-8578 (Japan); Tereshina, E.A. [Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, Prague, 18221 (Czech Republic); Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, Prague, 12116 (Czech Republic); Prokleska, J. [Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, Prague, 12116 (Czech Republic); Watanabe, K. [HFLSM, Institute for Materials Research, Tohoku University, Katahira 2-1-1, Sendai, 980-8578 (Japan)


    Study of magnetostriction of (Lu{sub 0.8}Ce{sub 0.2}){sub 2}Fe{sub 17} has been performed by two methods, bulk and microscopic: by the capacitor dilatometer on a single crystal grown by the Czochralski method and by the X-ray powder diffraction. The field-induced transition from the antiferromagnetic to the ferromagnetic state is accompanied by the lattice expansion both in the basal plane and along the c-axis of the hexagonal structure. In addition to the spontaneous linear magnetostriction {lambda}{sub a}{sup s}=0.8x10{sup -3}, {lambda}{sub c}{sup s}=6.8x10{sup -3} along the a and c axes, respectively, and volume effect {omega}{sub s} = 8.4 x 10{sup -3}, a comparable field-induced magnetostriction ({lambda}{sub a} = 1.3 x 10{sup -3}, {lambda}{sub c} = 3.4 x 10{sup -3}, {omega} = 6.0 x 10{sup -3}) is observed in a field of 5 T applied along the a-axis.

  17. DMT Method Approach for Liquefaction Hazard Vulnerability Mapping in Bantul Regency, Yogyakarta Province, Indonesia

    Khori Sugiarti


    Full Text Available DOI:10.17014/ijog.2.1.53-61On May 27 2006, an earthquake (Mw 6.2 occurring in Bantul, Yogyakarta Special Province, triggered liquefaction phenomenon such as sand boiling and lateral spreading. Knowledge of the liquefied soil layers is required to mitigate the hazard. The purpose of this research is to determine the depth and thickness of liquefiable soil layers using the flat blade dilatometer test (DMT method. The horizontal stress index values (KD obtained from the DMT were used to calculate the cyclic resistance ratio (CRR, while the PGA (peak ground acceleration calculated by the software EZ-FRISK 7.52 were employed to determine the cyclic stress ratio (CSR. The DMT-based liquefaction potential analysis shows that the thickness of liquefiable soil layers ranges from 1.8 to 4.0 m. These results show a good agreement with the previous analysis based on CPT (cone penetration test data. The analysis also indicated that, for the given earthquake magnitude and PGA, the liquefiable soil layers are characterized by a range of maximum KD value from 2.1 to 3.7.

  18. Mechanical properties of Municipal Solid Waste by SDMT

    Castelli, Francesco, E-mail: [Geotechnical Engineering, Faculty of Engineering and Architecture, Kore University of Enna, 94100 Enna (Italy); Maugeri, Michele [Geotechnical Engineering, Department of Civil and Environmental Engineering, University of Catania, 95125 Catania (Italy)


    Highlights: • The adoption of the SDMT for the measurements of MSW properties is proposed. • A comparison between SDMT results and laboratory tests was carried out. • A good reliability has been found in deriving waste properties by SDMT. • Results seems to be promising for the friction angle and Young’s modulus evaluation. - Abstract: In the paper the results of a geotechnical investigation carried on Municipal Solid Waste (MSW) materials retrieved from the “Cozzo Vuturo” landfill in the Enna area (Sicily, Italy) are reported and analyzed. Mechanical properties were determined both by in situ and laboratory large-scale one dimensional compression tests. While among in situ tests, Dilatomer Marchetti Tests (DMT) is used widely in measuring soil properties, the adoption of the DMT for the measurements of MSW properties has not often been documented in literature. To validate its applicability for the estimation of MSW properties, a comparison between the seismic dilatometer (SDMT) results and the waste properties evaluated by laboratory tests was carried out. Parameters for “fresh” and “degraded waste” have been evaluated. These preliminary results seems to be promising as concerns the assessment of the friction angle of waste and the evaluation of the S-wave in terms of shear wave velocity. Further studies are certainly required to obtain more representative values of the elastic parameters according to the SDMT measurements.

  19. Examination of DMT-based methods for evaluating the liquefaction potential of soils

    Gordon Tung-Chin KUNG; Der-Her LEE; Pai-Hsiang TSAI


    The flat dilatometer test(DMT)has the potential to be a useful tool in the evaluation ofliquefaction potential of soils.In practice,it is necessary to carefully examine existing DMT-based methods for evaluating liquefaction potential.We conducted the DMT and cone penetration test(CPT)in high liquefaction potential areas to examine the existing DMT-based methods for liquefaction potential evaluation.Specifically,the DMT and CPT were conducted side-by-side at each of six in-situ sites,and thus it is feasible to utilize those test results to validate the existing DMT-based methods.The DMT parameter,horizontal stress index(KD),is used as an indicator for estimating liquefaction resistance of soils in terms of cyclic resistance ratio(CRR).The analysis results revealed that the existing KD-based liquefaction evaluation methods would overestimate the CRR of soils,which leads to overestimation of the factor of safety against liquefaction.Also,the estimations of DMT-KD values by using the CPT-qc as well as the correlation between DMT-Ko and CPT-qc proposed by the previous studies would be significantly smaller than field measurements.The results reflected that further validation of the existing DMT-based methods for liquefaction evaluation is desirable.

  20. Characterization of Low Firing Temperature Ceramic Glaze Using Phuket MSW and Soda Lime Cullet

    Ketboonruang, P.; Jinawat, S.; Kashima, D. P.; Wasanapiarnpong, T.; Sujaridworakun, P.; Buggakuptav, W.; Traipol, N.; Jiemsirilers, S.


    The normal firing temperature of ceramic products is around 1200 °C. In order to reduce firing temperature, industrial wastes were utilized in ceramic glaze. Phuket municipal solid waste (MSW), soda lime cullet, and borax were used as raw materials for low firing temperature glazes. The glaze compositions were designed using a triaxial diagram. Stoneware ceramic body was glazed then fired at 1000 and 1150 °C for 15 minutes. Morphology and phase composition of glazes were analyzed by Scanning electron microscopy (SEM-EDS) and X-ray diffraction (XRD). Thermal expansion compatibility of Stoneware body and glazes were investigated using a dilatometer. Melting behaviour of selected glaze was analyzed by heating stage microscopy. Phuket MSW and Soda lime glass cullet can be used in high percentage as major raw materials for low firing temperature ceramic glaze that show good texture and vitrified at lower firing temperature without using any commercial ceramic frits. The firing temperature can be reduced up to 150 °C in this study.

  1. Evaluation of New Thermally Conductive Geopolymer in Thermal Energy Storage

    Černý, Matěj; Uhlík, Jan; Nosek, Jaroslav; Lachman, Vladimír; Hladký, Radim; Franěk, Jan; Brož, Milan

    This paper describes an evaluation of a newly developed thermally conductive geopolymer (TCG), consisting of a mixture of sodium silicate and carbon micro-particles. The TCG is intended to be used as a component of high temperature energy storage (HTTES) to improve its thermal diffusivity. Energy storage is crucial for both ecological and economical sustainability. HTTES plays a vital role in solar energy technologies and in waste heat recovery. The most advanced HTTES technologies are based on phase change materials or molten salts, but suffer with economic and technological limitations. Rock or concrete HTTES are cheaper, but they have low thermal conductivity without incorporation of TCG. It was observed that TCG is stable up to 400 °C. The thermal conductivity was measured in range of 20-23 W m-1 K-1. The effect of TCG was tested by heating a granite block with an artificial fissure. One half of the fissure was filled with TCG and the other with ballotini. 28 thermometers, 5 dilatometers and strain sensors were installed on the block. The heat transport experiment was evaluated with COMSOL Multiphysics software.

  2. Effect of rare earth doping on thermo-physical properties of lanthanum zirconate ceramic for thermal barrier coatings

    ZHOU Hongming; YI Danqing


    The effect of rare earth doping on thermo-physical properties of lanthanum zirconate was investigated. Oxide powders of various compositions La2Zr2O7 were synthesized by coprecipitation-calcination method. High-temperature dilatometer, DSC, and laser thermal dif-fusivity methods were used to analyze thermal expansion coefficient (TEC), specific heat, and thermal diffusivity. The results showed that CeO2 doped pyrochlores La2(Zr1.8Ce0.2)2O7 and La1.7(DyNd)0.15(Zr0.8Ce0.2)2O7 had higher TEC than La2Zr2O7 and Lal.7Dyo.3Zr207. La2(Zr1.8Ce0.2)2O7, La1.7Oy0.3Zr2O7, and La1.7(DyNd)0.15(Zr0.8Ce0.2)2O7 had lower thermal conductivity than undoped La2Zr2O7. The Dy203, Nd2O3, and CeO2 codoped composition showed the lowest thermal conductivity and the highest TEC. Thermo-physical results also indicated that TEC of rare earth oxide doped La2Zr2O7 ceramic was slightly higher than that of conventional ZrO2-8wt.% Y2O3 (8YSZ), and its thermal conductivity was lower than that of 8YSZ.

  3. NASA Tech Briefs, November 2005


    Topics covered include: Laser System for Precise, Unambiguous Range Measurements; Flexible Cryogenic Temperature and Liquid-Level Probes; Precision Cryogenic Dilatometer; Stroboscopic Interferometer for Measuring Mirror Vibrations; Some Improvements in H-PDLCs; Multiple-Bit Differential Detection of OQPSK; Absolute Position Encoders With Vertical Image Binning; Flexible, Carbon-Based Ohmic Contacts for Organic Transistors; GaAs QWIP Array Containing More Than a Million Pixels; AutoChem; Virtual Machine Language; Two-Dimensional Ffowcs Williams/Hawkings Equation Solver; Full Multigrid Flow Solver; Doclet To Synthesize UML; Computing Thermal Effects of Cavitation in Cryogenic Liquids; GUI for Computational Simulation of a Propellant Mixer; Control Program for an Optical-Calibration Robot; SQL-RAMS; Distributing Data from Desktop to Hand-Held Computers; Best-Fit Conic Approximation of Spacecraft Trajectory; Improved Charge-Transfer Fluorescent Dyes; Stability-Augmentation Devices for Miniature Aircraft; Tool Measures Depths of Defects on a Case Tang Joint; Two Heat-Transfer Improvements for Gas Liquefiers; Controlling Force and Depth in Friction Stir Welding; Spill-Resistant Alkali-Metal-Vapor Dispenser; A Methodology for Quantifying Certain Design Requirements During the Design Phase; Measuring Two Key Parameters of H3 Color Centers in Diamond; Improved Compression of Wavelet-Transformed Images; NASA Interactive Forms Type Interface - NIFTI; Predicting Numbers of Problems in Development of Software; Hot-Electron Photon Counters for Detecting Terahertz Photons; Magnetic Variations Associated With Solar Flares; and Artificial Intelligence for Controlling Robotic Aircraft.

  4. Influence of composition on the structure and properties of SrO–Sb2O3–P2O5 low-melting sealing glasses

    Nie Haining


    Full Text Available SrO–Sb2O3–P2O5 glass system was prepared by high temperature melting method. The effects of Sb2O3 and P2O5 content on the structure, thermal behavior and chemical durability of the glasses were studied by infrared spectrometer, thermal dilatometer, differential thermal analyzer and constant temperature water bath heating. It can be concluded that the characteristic temperatures of the glasses increased firstly and then decreased with the increasing of Sb2O3 content, whereas the tendency of the coefficient of thermal expansion (CTE varied inversely. The crystallization ability of the glasses was significantly increased and the water resistance was reduced for Sb2O3 content of 35 mol % and 40 mol %. The glasses with 20 mol %, 25 mol % and 30 mol % Sb2O3 showed better performance in every respect than the others and the glasses containing 25 mol % Sb2O3, characterized by the best performance, can be chosen as host glasses for further research.

  5. Thermal expansion of glasses at low temperatures

    Lyon, K.G.


    The linear thermal expansion coefficient (..cap alpha.. = (par. deltalnL/par. deltaT)/sub p/) was measured at temperatures to 1.2K for two amorphous solids, fused silica and PMMA (polymethylmethacrylate, plexiglas), using a parallel plate capacitor differential dilatometer. The low temperature expansion coefficients for these solids have the same temperature dependences as the specific heats, and show a contribution which is linear in the temperature and which can be associated with the postulate of a broad distribution of two level states. The Grueneisen parameters which are associated with this contribution are comparable for the two solids (Y approx. = -16), and suggest a further indication of common behavior for amorphous solids at low temperature. Large magnitudes for Grueneisen parameters (/..gamma../ > 5) generally are associated with tunneling models. A symmetric double harmonic oscillator tunneling model can be used to understand the sign and magnitude of ..gamma.. for these solids. This model is inconsistent with other thermal and thermodynamic data for fused silica. The existence of similar negative and large magnitude Grueneisen parameters for these two amorphous solids places an additional constraint on theories for the low temperature properties of glasses.

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

    Zhao, Dapeng, E-mail: [College of Biology, Hunan University, 410082 Changsha (China); Helmholtz-Zentrum Geesthacht, Institute of Materials Research, D-21502 Geesthacht (Germany); Chang, Keke [RWTH Aachen University, Materials Chemistry, D-52056 Aachen (Germany); Ebel, Thomas [Helmholtz-Zentrum Geesthacht, Institute of Materials Research, D-21502 Geesthacht (Germany); Nie, Hemin [College of Biology, Hunan University, 410082 Changsha (China); Willumeit, Regine; Pyczak, Florian [Helmholtz-Zentrum Geesthacht, Institute of Materials Research, D-21502 Geesthacht (Germany)


    Highlights: • The sintering of the MIM Ti–Nb alloy consists of three steps. • The Nb particles act as diffusion barriers during sintering. • The TiC{sub x} only precipitate in the cooling step during sintering. • The TiC{sub 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.

  7. Determination of Recrystallization Temperature of Reverted Austenite of C-250 Maraging Steel%C-250马氏体时效钢逆变奥氏体再结晶温度的测定

    赵飞; 秦路平; 魏志坚; 张华


    Based on the theory of phase transformation and recrystallization accompanied with thermal effect and volume effect, the austenization temperature and reverted austenite recrystallization temperature of C-250 maraging steel was determined by DSC and dilatometer.The austenization temperature is As ≈ 647 ℃ and Af≈ 780 ℃, while the recrystallization temperature of reverted austenite is 923.1 ℃.%利用相变过程和逆变再结晶过程伴随着热效应体积效应的原理,采用热分析和热膨胀相结合的方法来测定C-250马氏体时效钢的奥氏体化温度和逆变奥氏体再结晶温度.结果显示,C-250马氏体时效钢的奥氏体化温度为A≈647℃,A≈780℃,逆变奥氏体再结晶温度为923.1℃.

  8. Evaluation on Properties of CaO-BaO-B2O3-Al2O3-SiO2 Glass-Ceramic Sealants for Intermediate Temperature Solid Oxide Fuel Cells

    Fatemeh Heydari; Amir Maghsoudipour; Zohreh Hamnabard; Sajad Farhangdoust


    To develop suitable sealants for intermediate temperature solid oxide fuel cells (IT-SOFC),glass-ceramics based on the CaO-BaO-B2O3-Al2O3-SiO2 system were studied.Coefficient of thermal expansion (CTE),glass transition temperature (Tg) and dilatometric softening point temperature (Td) of specimens were determined by means of dilatometer analysis and crystallization temperature was measured by differential thermal analysis (DTA).Also,crystallization behavior during prolonged heat-treatment and microstructure properties were studied by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM),respectively.Electrical properties were measured at different temperatures,and the results showed a high resistance (>104 Ω) at the SOFC operation temperature (600-800 ℃).Moreover,mechanical properties of heat-treated specimens (1,10,30,50 h) were measured.Microstructure investigation revealed a well-adhered bonding between the sealant glass-ceramic electrolyte and glass.

  9. Study of microstructural evolution, microstructure-mechanical properties correlation and collaborative deformation-transformation behavior of quenching and partitioning (Q and P) steel

    Sun, Jing; Yu, Hao, E-mail:; Wang, Shaoyang; Fan, Yongfei


    This paper presents a detailed characterization of the microstructural evolution of quenching and partitioning (Q and P) steel by dilatometer, X-ray diffraction and scanning electron microscopy. Influence of partitioning time on mechanical properties was investigated and the relationship between microstructures and mechanical properties was established. The results indicate that bainite transformation occurs at the preliminary stage of partitioning and the amount is proportional to quenching temperature. Martensite softening, bainite transformation kinetics, amount and stability of retained austenite collaboratively have effects on mechanical properties. The purpose of the EBSD investigation is to study the changes in the microstructure of the Q and P steel during deformation and obtain a better understanding of collaborative deformation-transformation behavior. During deformation, plastic deformation preferentially occurred in the vicinity of ferrite–martensite interfaces and spread to the interior of ferrite grain with strain increasing. Plastic deformation started to occur in martensite after large strain. Furthermore, grain rotation occurred in some austenite grains or divided into subgrains during deformation.

  10. Assessing the oxygen stoichiometry during the sintering of (U, Pu)O2 fuel

    Vaudez, Stéphane; Léchelle, Jacques; Berzati, Ségolène; Heintz, Jean-Marc


    Diffusion phenomena occurring in ceramics such as (U, Pu)O2 during sintering are affected by the oxygen content in the atmosphere. The latter sets the nature and the concentration of point defects which govern diffusion mechanisms in the bulk of the material. The oxygen partial pressure, pO2, of the sintering gas in equilibrium with mixed oxide (MOX) pellets needs to be precisely controlled; otherwise it may induce a large dispersion in the critical parameters for fuel manufacturing (Gauche, 2013; Matzke, 1987). It is crucial to understand the relation between the sintering atmosphere and the fuel throughout the thermal cycle. In this study, the oxygen potential of the sintering gas was monitored by measuring the oxygen partial pressure (pO2) at the outlet of a dilatometer by means of a zirconia probe. Coupling the thermal cycle with an outlet gas pO2 measurement makes it possible to identify different redox phenomena. Variations in the oxygen stoichiometry can be determined during the sintering of (U, Pu)O2, as well as can its final O/M. Our results make it possible to recommend a sintering atmosphere and sintering thermal cycle in order to obtain an O/M ratio that is as close as possible to the target value.

  11. On Various Aspects of Decomposition of Austenite in a High-Silicon Steel During Quenching and Partitioning

    Somani, Mahesh Chandra; Porter, D. A.; Karjalainen, L. P.; Misra, R. D. K.


    Using a Gleeble thermomechanical simulator, a high-silicon steel (Fe-0.2C-1.5Si-2.0Mn-0.6Cr) was laboratory hot-rolled, re-austenitized, quenched into the M s-M f range, retaining 15 to 40 pct austenite at the quench stop temperature (T Q), and annealed for 10 to 1000 seconds at or above T Q in order to better understand the mechanisms operating during partitioning. Dilatometer measurements, transmission electron microscopy, and calculations showed that besides carbon partitioning, isothermal martensite and bainite form at the partitioning temperature. While isothermal martensite formation starts almost immediately after quenching with the rate of volume expansion dropping all the time, the beginning of bainite formation is marked by a sudden increase in the rate of expansion. The extent of its formation depends on the partitioning temperature following TTT diagram predictions. At the highest partitioning temperatures martensite tempering competes with partitioning. Small fractions of bainite and high-carbon martensite formed on cooling from the partitioning temperature. The average carbon content of the austenite retained at room temperature as determined from XRD measurements was close to the carbon content estimated from the M s temperature of the martensite formed during the final cooling.

  12. Characterization of BaTiO$_3$ piezoelectric perovskite material for multilayer actuators



    In this study, we present the results of the manufacturing of BaTiO$_3$ powder, which is meant for use in stacked-diskmultilayer actuator production. The solid-state technique was used for powder preparation. The properties of bariumtitanate material, at each stage of its fabrication (powder, granulate, sintered material), influencing on its application forthe stacked-disk multilayer actuator were determined. Particularly, the four parameters of BaTiO$_3$ sinter affecting on theusability properties of actuators, not found before in the literature, were estimated. Parameters characterizing the extent ofmaterial sintering, SEM microstructures and electric properties of the fabricated pellets are presented and discussed. Thedilatometric curve was executed using the high temperature dilatometer to determine at which temperature barium titanatepellets and beams should be sintered to receive full dense sinters. Parameters characterizing the extent of material sintering:the apparent density, the apparent porosity and the water absorbability were estimated. Finally, the problem of metal layerdeposition on barium titanate ceramics during actuator fabrication is considered.

  13. Inverse Process Analysis for the Acquisition of Thermophysical Data

    Jay Frankel (UTK); Adrian Sabau (UTK)


    One of the main barriers in the analysis and design of materials processing and industrial applications is the lack of accurate experimental data on the thermophysical properties of materials. To date, the measurement of most of these high-temperature thermophysical properties has often been plagued by temperature lags that are inherent in measurement techniques. These lags can be accounted for with the appropriate mathematical models, reflecting the experimental apparatus and sample region, in order to deduce the desired measurement as a function of true sample temperature. Differential scanning calorimeter (DSC) measurements are routinely used to determine enthalpies of phase change, phase transition temperatures, glass transition temperatures, and heat capacities. In the aluminum, steel, and metal casting industries, predicting the formation of defects such as shrinkage voids, microporosity, and macrosegregation is limited by the data available on fraction solid and density evolution during solidification. Dilatometer measurements are routinely used to determine the density of a sample at various temperatures. An accurate determination of the thermophysical properties of materials is needed to achieve accuracy in the numerical simulations used to improve or design new material processes. In most of the instruments used to measure properties, the temperature is changed according to instrument controllers and there is a nonhomogeneous temperature distribution within the instrument. Additionally, the sample temperature cannot be measured directly: temperature data are collected from a thermocouple that is placed at a different location than that of the sample, thus introducing a time lag. The goal of this project was to extend the utility, quality and accuracy of two types of commercial instruments -a DSC and a dilatometer - used for thermophysical property measurements in high-temperature environments. In particular, the quantification of solid fraction and

  14. DMT Method Approach for Liquefaction Hazard Vulnerability Mapping in Bantul Regency, Yogyakarta Province, Indonesia

    Khori Sugiarti


    Full Text Available DOI:10.17014/ijog.2.1.53-61On May 27 2006, an earthquake (Mw 6.2 occurring in Bantul, Yogyakarta Special Province, triggered liquefaction phenomenon such as sand boiling and lateral spreading. Knowledge of the liquefied soil layers is required to mitigate the hazard. The purpose of this research is to determine the depth and thickness of liquefiable soil layers using the flat blade dilatometer test (DMT method. The horizontal stress index values (KD obtained from the DMT were used to calculate the cyclic resistance ratio (CRR, while the PGA (peak ground acceleration calculated by the software EZ-FRISK 7.52 were employed to determine the cyclic stress ratio (CSR. The DMT-based liquefaction potential analysis shows that the thickness of liquefiable soil layers ranges from 1.8 to 4.0 m. These results show a good agreement with the previous analysis based on CPT (cone penetration test data. The analysis also indicated that, for the given earthquake magnitude and PGA, the liquefiable soil layers are characterized by a range of maximum KD value from 2.1 to 3.7.

  15. Thermal activation analysis of the structural and phase transformations in the Zr-Cu-Nb amorphous alloy

    Fedotova N.L.


    Full Text Available In the present work, the procedure of the estimation of the thermal activation parameters from the data of dilatometric measurements and the results of its application to the Zr-Cu-Nb amorphous alloy discussed. The determination of the thermal activation parameters of the processes occurring in materials under known temperature-force conditions can be useful for the identification of the structural mechanisms of phase transformations and the evolution of defect structure. We used the data of dilatometric measurements for evaluating the effective activation energy. This method exhibits some advantages over the conventional one due to the design features of dilatometers. First, it ensures the precise measurement of strains; second, the assigned temperature regime is very precisely maintained both at the stage of heating and upon isothermal holding; third, it ensures a high-speed continuous record of the experimental data. The developed method of evaluating the effective activation energy from the results of dilatometric experiments provides statistically reliable results. The data of the photometric analysis of structure images are in accordance with the results of dilatometric experiments

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

    Bianchi, Laura; 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...


    Bianchi, Laura


    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...

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

    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)


    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.

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

    Kétner Bendo Demétrio


    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.

  20. Characterization of (Th,U)O 2 fuel pellets made by impregnation technique

    Kutty, T. R. G.; Nair, M. R.; Sengupta, P.; Basak, U.; Kumar, Arun; Kamath, H. S.


    Impregnation technique is an attractive alternative for manufacturing highly radiotoxic 233U bearing thoria based mixed oxide fuel pellets, which are remotely treated in hot cell or shielded glove-box facilities. This technique is being investigated to fabricate the fuel for the forthcoming Indian Advanced Heavy Water Reactor (AHWR). In the impregnation process, porous ThO 2 pellets are prepared in an unshielded facility which are then impregnated with 1.5 molar uranyl nitrate solution in a shielded facility. The resulting composites are dried and denitrated at 500 °C and then sintered in reducing/oxidizing atmosphere to obtain high density (Th,U)O 2 pellets. In this work, the densification behaviour of ThO 2-2% UO 2 and ThO 2-4% UO 2 pellets was studied in reducing and oxidizing atmospheres using a high temperature dilatometer. Densification was found to be larger in air than in Ar-8% H 2. The characterization of the sintered pellets was made by optical microscopy, scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). The grain structure of ThO 2-2% UO 2 and ThO 2-4% UO 2 pellets was uniform. The EPMA data confirmed that the uranium concentration was slightly higher at the periphery of the pellet than that at the centre.

  1. Investigation of thermodynamics properties of chalcopyrite compound CdGeAs2

    Huang, Wei; Zhao, Beijun; Zhu, Shifu; He, Zhiyu; Chen, Baojun; Zhen, Zhen; Pu, Yunxiao; Liu, Weijia


    Chalcopyrite of CdGeAs2 single crystal was grown by a modified vertical Bridgman method with sufficient size and quality, and its optical, electrical and thermodynamic properties are characterized. The transmission is recorded in the 2.3-18 μm range, and the band-gap at room temperature is at 0.56 eV. Non-ideal transparency near 5.5 μm which limited its application severely exists in the front of the crystal. The crystal is p type at room temperature with hole concentrations varying from 1014 to 1016 cm-3. From the results of X-ray diffraction measurements carried out over the range 25-450 °C and thermal dilatometer tests, the thermal expansion coefficients are evaluated. And on this basis the Grüneisen parameters at different temperatures are evaluated and also exhibit anisotropic behavior (γa>γc). It is found that γa, γc, and γV have some difference between these two kinds of test methods. Using these Grüneisen parameters, lattice thermal conductivities have been deduced by two correction formulas. Meanwhile, specific heat capacity and thermal conductivity of [204] have been obtained as a function of temperature by experiment.

  2. Phase transformation studies in U–Nb–Zr alloy

    Lopes, Denise Adorno [Laboratório de Materiais Nucleares, Centro Tecnológico da Marinha em São Paulo, 18560-000 Iperó, SP (Brazil); Departamento de Engenharia Metalúrgica e de Materiais, Escola Politécnica – USP, 05508-030 São Paulo (Brazil); Restivo, Thomaz Augusto Guisard, E-mail: [Departamento de Engenharia Metalúrgica e de Materiais, Escola Politécnica – USP, 05508-030 São Paulo (Brazil); Universidade de Sorocaba UNISO, Rod. Raposo Tavares km 92.5, 18023-000 Sorocaba, SP (Brazil); Padilha, Angelo Fernando [Departamento de Engenharia Metalúrgica e de Materiais, Escola Politécnica – USP, 05508-030 São Paulo (Brazil)


    Highlights: • We employ drop calorimetry under up-quenching mode to detect alloy transformation kinetics for the first time. • Two processing windows for rolling U–Zr–Nb alloy into γ-phase are found at 200 and 400 °C. • Volume changes are measured for the main transformations. • We infer fast transformations from the alloy heating enthalpy curve. - Abstract: Phase transformation diagrams provide fundamental informations for designing thermomechanical processes being a must regarding uranium alloys nuclear fuels. The work shows the evaluation of a kinetic transformation diagram for U–7.5Nb–2.5Zr (wt.%) based on both calorimetry experiments and dilatometry allied to X-ray diffraction analysis. Calorimetry measurements in scanning and drop modes can detect enthalpies of heating and transformation onset points from ambient up to select isotherms while the dilatometer is used to scan for sample volume changes related to phase transformations. The resulted kinetic diagram shows the gamma phase is stable for this alloy, guiding the rolling deformation process to temperature ranges where this phase remains for longer periods. Comparing to the literature results, the low temperature transformation (300–400 °C) is shifted to longer times accordingly to the disclosed TTT kinetic diagram. Therefore, two forming process windows can be proposed at 200 °C and 400 °C neighborhood where gamma-phase remains for enough time to accomplish total reduction.

  3. CO2 Interaction with Geomaterials (Invited)

    Romanov, V.; Howard, B. H.; Lynn, R. J.; Warzinski, R. P.; Hur, T.; Myshakin, E. M.; Lopano, C. L.; Voora, V. K.; Al-Saidi, W. A.; Jordan, K. D.; Cygan, R. T.; Guthrie, G. D.


    This work compares the sorption and swelling processes associated with CO2-coal and CO2-clay interactions. We investigated the mechanisms of interaction related to CO2 adsortion in micropores, intercalation into sub-micropores, dissolution in solid matrix, the role of water, and the associated changes in reservoir permeability, for applications in CO2 sequestration and enhanced coal bed methane recovery. The structural changes caused by CO2 have been investigated. A high-pressure micro-dilatometer was equipped to investigate the effect of CO2 pressure on the thermoplastic properties of coal. Using an identical dilatometer, Rashid Khan (1985) performed experiments with CO2 that revealed a dramatic reduction in the softening temperature of coal when exposed to high-pressure CO2. A set of experiments was designed for -20+45-mesh samples of Argonne Premium Pocahontas #3 coal, which is similar in proximate and ultimate analysis to the Lower Kittanning seam coal that Khan used in his experiments. No dramatic decrease in coal softening temperature has been observed in high-pressure CO2 that would corroborate the prior work of Khan. Thus, conventional polymer (or “geopolymer”) theories may not be directly applicable to CO2 interaction with coals. Clays are similar to coals in that they represent abundant geomaterials with well-developed microporous structure. We evaluated the CO2 sequestration potential of clays relative to coals and investigated the factors that affect the sorption capacity, rates, and permanence of CO2 trapping. For the geomaterials comparison studies, we used source clay samples from The Clay Minerals Society. Preliminary results showed that expandable clays have CO2 sorption capacities comparable to those of coal. We analyzed sorption isotherms, XRD, DRIFTS (infrared reflectance spectra at non-ambient conditions), and TGA-MS (thermal gravimetric analysis) data to compare the effects of various factors on CO2 trapping. In montmorillonite, CO2

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

    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

  5. Enhanced ionic conductivity of apatite-type lanthanum silicate electrolyte for IT-SOFCs through copper doping

    Ding, Xifeng; Hua, Guixiang; Ding, Dong; Zhu, Wenliang; Wang, Hongjin


    Apatite-type Lanthanum silicate (LSO) is among the most promising electrolyte for intermediate temperature solid oxide fuel cells (IT-SOFCs) owing to the high conductivity and low activation energy at lower temperature than traditional doped-zirconia electrolyte. The ionic conductivity as well as the sintering density of lanthanum silicate oxy-apatite, La10Si6-xCuxO27-δ (LSCO, 0 ≤ x ≤ 2), was effectively enhanced through a small amount of doped copper. The phase composition, relative density, ionic conductivity and thermal expansion behavior of La10Si6-xCuxO27-δ was systematically investigated by X-ray diffraction (XRD), Archimedes' drainage method, scanning electron microscope (SEM), electrochemical impedance spectra (EIS) and thermal dilatometer techniques. With increasing copper doping content, the ionic conductivity of La10Si6-xCuxO27-δincreased, reaching a maximum of 4.8 × 10-2 S cm-1 at 800 °C for x = 1.5. The improved ionic conductivity could be primarily associated with the enhanced grain conductivity. The power output performance of NiO-LSCO/LSCO/LSCF single cell was superior to that obtained on NiO-LSO/LSO/LSCF at different temperatures using hydrogen as fuel and oxygen as oxidant, which could be attributed to the enhanced oxygen ionic conductivity as well as the sintering density for the copped doped lanthanum silicate. In conclusion, the apatite La10Si4.5Cu1.5O25.5 is a promising candidate electrolyte for IT-SOFCs.

  6. A multidisciplinary methodology for the characterization of a large rock spread in the Northern Calcareous Alps (Eastern Alps)

    Melzner, Sandra; Ottowitz, David; Pfeiler, Stefan; Moser, Michael; Motschka, Klaus; Lotter, Michael; Mandl, Gerhard Walter; Rohn, Joachim; Otter, Juergen; Wimmer-Frey, Ingeborg


    The Northern Calcareous Alps are characterized by complex lithological and tectonic settings, which are a consequence of the multiphase Alpine orogeny. Several tectonic events caused a varying structural anisotropy with a high susceptibility towards certain types of gravitational mass movement. Mt. Plassen is situated west of the Hallstatt village (Upper Austria). It is composed of Jurassic limestone, which overlies Permotriassic fine-grained clastic rocks and evaporites (mainly part of the so-called Haselgebirge). This geotechnical predisposition causes rock spreading of the more hard and rigid limestone on the weak, mainly clayey rocks. Associated to this large slope instability are secondary rockfall and sliding processes. Further common process chains include rockfall triggering slides and/or earth flows by undrained loading of the ductile clay material. Thus, such fast moving flows/slides may endanger the houses and infrastructures in the Salzberg high valley and Hallstatt village. Recent rockfall activity at Mt. Plassen provide evidences for greater, perhaps accelerating displacement rates of the rock spread. A multidisciplinary assessment strategy was chosen to analyse the ground conditions, to characterize the potential failure mechanisms in more detail and to evaluate the hazard potential of future events. Methods include field mapping (geologic, engineering geologic and geomorphologic), sampling and determination of soil parameters in active process areas, geophysical surveys (airborne geophysics and geoelectric measurements) and kinematic measurements (tape dilatometer and geodetic measurements over a period of 50 years). Results of this multidisciplinary approach form the basis for further decision making such as the installation of a monitoring system or other preventive measures.

  7. Mechanical properties of hot deformed Inconel 718 and X750

    A. Nowotnik


    Full Text Available Purpose: Variations of a flow stress vs. true strain illustrate behavior of material during plastic deformation. Stress-strain relationship is generally evaluated by a torsion, compression and tensile tests.Design/methodology/approach: Compression tests were carried out on precipitations hardenable nickel based superalloys of Inconel 718 and X750 at constant true strain rates of 10-4, 4x10-4s-1 within temperature through which precipitation hardening phases process occurred (720-1150°C using thermomechanical simulator Gleeble and dilatometer Baehr 850D/L equipped with compression unit. True stress-true strain curves analysis of hot deformed alloys were described.Findings: On the basis of received flow stress values activation energy of a high-temperature deformation process was estimated. Mathematical dependences (σpl -T i σpl - ε and compression data were used to determine material’s constants. These constants allow to derive a formula that describes the relationship between strain rate (ε, deformation temperature (T and flow stress σpl.Research limitations/implications: Study the flow stress will be continued on the samples after the aging process.Practical implications: The results of high-temperature deformation of the examined Inconel alloys may possibly find some practical use in the workshop practice to predict a flow stress values, but only within particular temperature and strain rate ranges. The results of the study can be used in the aerospace industry to produce blades for jet engines.Originality/value: The results of the study can be used in the aerospace industry to produce blades for jet engines.

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

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


    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.

  9. Fabrication and evaluation of Bis-GMA/TEGDMA dental resins/composites containing halloysite nanotubes.

    Chen, Qi; Zhao, Yong; Wu, Weidong; Xu, Tao; Fong, Hao


    To investigate the reinforcement of Bis-GMA/TEGDMA dental resins (without conventional glass filler) and the corresponding composites (with conventional glass filler) containing varied mass fractions of halloysite nanotubes (HNTs). Three dispersion methods were studied to separate the silanized halloysite as individual HNTs and to uniformly distribute them into dental matrices. Photopolymerization induced volumetric shrinkage was measured by using a mercury dilatometer. Real time near infrared spectroscopy was adopted to study the degree of vinyl double bond conversion and the photopolymerization rate. Mechanical properties of the composites were tested by a universal mechanical testing machine. Analysis of variance (ANOVA) was used for the statistical analysis of the acquired data. Morphologies of halloysite/HNTs and representative fracture surfaces of the reinforced dental resins/composites were examined by SEM and TEM. Impregnation of small mass fractions (e.g., 1% and 2.5%) of the silanized HNTs in Bis-GMA/TEGDMA dental resins/composites improved mechanical properties significantly; however; large mass fractions (e.g., 5%) of impregnation did not further improve the mechanical properties. The impregnation of HNTs into dental resins/composites could result in two opposite effects: the reinforcing effect due to the highly separated and uniformly distributed HNTs, and the weakening effect due to the formation of HNT agglomerates/particles. Uniform distribution of a small amount of well-separated silanized HNTs into Bis-GMA/TEGDMA dental resins/composites could result in substantial improvements on mechanical properties. Copyright © 2012 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  10. Properties of silorane-based dental resins and composites containing a stress-reducing monomer.

    Eick, J David; Kotha, Shiva P; Chappelow, Cecil C; Kilway, Kathleen V; Giese, Gregory J; Glaros, Alan G; Pinzino, Charles S


    To evaluate properties of silorane-based resins and composites containing a stress reducing monomer. Resin mixtures and composites were formulated containing (a) a developmental stress reducing monomer [TOSU; Midwest Research Institute]; (b) Sil-Mix (3M-ESPE); (c) photo cationic initiator system. Standard BISGMA/TEGDMA resin (B/T) and composite (Filtek Z250) were used as controls. Polymerization volume change was measured using a NIST mercury dilatometer and polymerization stress using an Enduratec mechanical testing machine. Three point bend tests determined flexural elastic modulus, work of fracture, and ultimate strength (ADA 27; ISO 4049). Fracture toughness was measured using ASTM E399-90. Four groups of resins and composites were tested: Sil-Mix, methacrylate standard, and Sil-Mix with two addition levels of TOSU. An ANOVA was used and significant differences ranked using Student-Newman-Keuls test (alpha=0.05). Polymerization stress values for resins containing TOSU were significantly less than the other materials. Polymerization shrinkage values for Sil-Mix formulations were significantly less than for B/T, but were not different from each other. TOSU-containing formulations generally had somewhat lower mechanical properties values than Sil-Mix or B/T. Polymerization stress values for Sil-Mix-based composites were significantly less as compared to Z250. The 1wt.% TOSU composite had the lowest stress. No difference between composite groups was noted for fracture toughness or work of fracture. For ultimate strength, the 5wt.% TOSU formulation differed significantly from Z250. All Sil-Mix formulations had elastic modulus values significantly different from Z250. The ability of TOSU to reduce polymerization stress without a proportional reduction in mechanical properties provides a basis for improvement of silorane-based composites.

  11. Lightweighted ZERODUR for telescopes

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


    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.

  12. 加热温度对TRIP钢连续冷却转变曲线及室温组织的影响%Effect of heating temperature on the continuous cooling transformation and microstructure of TRIP steel

    范东亮; 米振莉; 李志超; 刘强


    采用膨胀法在DIL805热膨胀仪上测定了不同加热温度下实验钢的连续冷却转变(CCT)曲线,通过光学显微镜和扫描电镜分析不同加热温度对CCT曲线和冷却试样显微组织的影响.结果表明:当加热温度由完全奥氏体化温度降低到两相区内较高温度时,CCT曲线中铁素体转变区左移;当加热温度处在两相区范围内时,随着加热温度的降低,铁素体转变被推迟,使得CCT曲线右移;新生铁素体外延生长方式和奥氏体中碳富集程度的差异是导致上述变迁的主要因素.%The continuous cooling transformation (CCT) curves of experimental steel were determined by thermal dilation method with a DIL805 thermal dilatometer. Optical microscopy and scan electron microscopy (SEM) were used to analyze the effect of heating temperature on the CCT curves and the microstructure of cooled samples. Experimental results show that when the heating temperature decreases from the complete austenitizing temperature to a higher temperature of the two-phase region, the ferrite transformation of the CCT curve shifts to the left. And when the heating temperature changes in the two-phase region, the ferrite transformation is postponed with the heating temperature decreasing, leading to that the CCT curve shifts to the right. The epitaxial growth mode of new ferrite and the carbon enrichment difference of austenite are principal factors that cause the shifts mentioned above.

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

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


    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.

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

    H. A. A. Sidek


    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.

  15. Effects of B4C addition on the micro- structural and thermal properties of hot pressed SiC ceramic matrix composites

    Z. Keçeli


    Full Text Available Purpose: The purpose of paper is to evaluate effects of B4C addition on the microstructural and thermal properties of hot pressed SiC ceramic matrix composites.Design/methodology/approach: The effect of B4C addition on microstructural and thermal properties of the SiC-B4C powder composites were investigated after high energy milling and hot pressing. SiC powders containing 5wt%, 10wt%, 15wt% B4C were mechanically alloyed in a high energy ball mill for 8 h.Findings: Microstructural characterisation investigations (SEM, XRD were carried out on mechanically alloyed SiC powder composites containing 5 wt %, 10 wt %, 15 wt % B4C powders and on these powder composites sintered in vacuum at 50 MPa at 2100ºC. The thermal properties were characterised using DTA, TGA and dilatometer. The results were evaluated.Research limitations/implications: In this study, the effect of B4C addition on microstructural and mechanical properties of the SiC-B4C powder composites was investigated after high energy milling and hot pressing.Originality/value: Ceramic matrix composite (CMC material systems are stimulating a lot of interest to be used and provide unique properties for aircraft and land-based turbine engines, defence applications, rocket motors, aerospace hot structures and industrial applications. Boron carbide (B4C-silicon carbide (SiC ceramic composites are very promising armour materials because they are intrinsically very hard. Advanced SiC-based armour is desired so that the projectile is completely defeated without penetrating the ceramic armour.

  16. Micro-nanocomposites Al{sub 2}O{sub 3}/ NbC/ WC and Al{sub 2}O{sub 3}/ NbC/ TaC; Micro-nanocompositos de Al{sub 2}O{sub 3}/ NbC/ WC e Al{sub 2}O{sub 3}/ NbC/ TaC

    Santos, Thais da Silva


    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{sub 2}O{sub 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)

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

    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: [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)


    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.

  18. 12MnNiVR钢的连续冷却转变行为及相变动力学%Continuous cooling transformation behavior and transformation kinetics of 12MnNiVR steel

    张志敏; 蔡庆伍; 余伟


    用热膨胀仪测定了12MnNiVR钢的连续冷却转变曲线,并结合显微组织观察和硬度测定,研究了低冷速下奥氏体向铁素体转变及向贝氏体转变的动力学,分析了铁素体转变及贝氏体转变的生长方式.实验钢在连续冷却过程中的计算相变动力学结果与实测相变数据吻合很好.研究结果表明实验钢在低冷速下冷却时奥氏体向铁素体转变,形核位置主要在晶棱处,生长方式主要为二维长大,奥氏体向贝氏体转变,形核位置主要在界面处,生长方式主要为一维长大.%Continuous cooling transformation curves of 12MnNiVR steel were measured by a thermal dilatometer, and then transformation kinetics of austenite to ferrite at low cooling rate as well as austenite to bainite was studied and growth modes of transformed ferrite and bainite were analyzed on the basis of measured CCT curves, and observation of microstructure and hardness measurement. The calculated result of transformation kinetics for the tested steel during continuous cooling is in reasonable agreement with experimental data. Results show that nucleation sites of ferrite transformed from austenite at low cooling rate are mainly at crystal edges and ferrite grains grow mainly following two-dimensional mode whereas nucleation sites of transformed bainite are mainly at austenite grain boundaries and bainite grains grow mainly following one-dimensional mode.

  19. Fabrication and Characterization of a Conduction Cooled Thermal Neutron Filter

    Heather Wampler; Adam Gerth; Heng Ban; Donna Post Guillen; Douglas Porter; Cynthia Papesch


    Installation of a conduction cooled thermal (low-energy) neutron filter in an existing domestic test reactor would provide the U.S. the capability to test new reactor fuels and materials for advanced fast (high-energy) reactor concepts. A composite consisting of Al3Hf-Al has been proposed for the neutron filter due to both the neutron filtering properties of hafnium and the conducting capabilities of aluminum. Knowledge of the thermal conductivity of the Al3Hf-Al composite is essential for the design of the filtering system. The present objectives are to identify a suitable fabrication technique and to measure the thermophysical properties of the Al3Hf intermetallic, which has not been done previous to this study. A centrifugal casting method was used to prepare samples of Al3Hf. X-ray diffraction and Rietveld analysis were conducted to determine the structural make-up of each of the samples. Thermophysical properties were measured as follows: specific heat by a differential scanning calorimeter (DSC), thermal diffusivity by a laser flash thermal diffusivity measuring system, thermal expansion by a dilatometer, and thermal conductivity was calculated based on the previous measurements. All measurements were acquired over a temperature range of 90°C - 375°C with some measurements outside these bounds. The average thermal conductivity of the intermetallic Al3Hf (~7 at.% Hf) was found to be ~ 41 W/m-K for the given temperature range. This information fills a knowledge gap in the thermophysical properties of the intermetallic Al3Hf with the specified percentage of hafnium. A model designed to predict composite properties was used to calculate a thermal conductivity of ~177 W/m-K for an Al3Hf-Al composite with 23 vol% Al3Hf. This calculation was based upon the average thermal conductivity of Al3Hf over the specified temperature range.

  20. 低碳钛、钒微合金钢中的相间析出%Interphase precipitation in low carbon Ti-V microalloyed steels

    贾涛; 魏娇; 冯洁; 张维娜; 刘振宇; 王国栋


    The present study focuses on the Ti-V microalloying system which draws less attention. By using the Formaster-FII dilatometer,the sample was held at austenite/ferrite dual-phase temperature region and the Ti-V complex interphase precipitates were obtained during the austenite to ferrite transformation. Optical Microscopy (OM) and transmission electron microscopy (TEM) were employed to analyze the microstructure , especially the morphology of the interphase precipitate and its crystallographic orientation relationship with ferrite matrix. Studies show that 650℃is the nose temperature for static isothermal transforma-tion. The interphase precipitates exhibit sheet-like distribution,including flat and curved sheets and adopt Baker-Nutting orientation relationships with the ferrite matrix.%针对目前较少关注的Ti-V微合金体系,在Formaster-FII膨胀仪上进行奥氏体/铁素体两相区等温,在铁素体相变同时获得Ti、V复合相间析出。采用金相、透射电子显微镜对显微组织、尤其是相间析出形貌、及其与铁素体基体的位向关系进行了观察与分析。研究表明,650℃为静态等温相变的鼻温点,相间析出呈层状分布,具有平面和曲面两种形貌,相间析出碳化物与铁素体基体之间存在Baker-Nutting取向关系。

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

    G. Gasparotto


    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.

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

    Walls, P


    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

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

    Walls, P


    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

  4. Y2O3与Gd2O3共掺杂SrZrO3热障涂层材料的热物理性能%Thermophysical Properties of Y2O3 and Gd2O3 Co-doped SrZrO3 Thermal Barrier Coating Material

    马文; 宋峰雨; 董红英; 许萍; 伦文山; 郑学斌


    Y2O3 (5mol%) and Gd2O3 (5mol%) co-doped SiZrO3 (Sr(Zr0.9Y0.05Gd0.05)O2.95, SZYG) was synthesized by solid state reaction method. The phase stability of the SZYG powder synthesized at high temperature of 1450°C for a long period and at temperature range of 200-1400°C was characterized by XRD and DSC, respectively. The coefficients of thermal expansion (CTEs) of bulk SZYG recorded by a high-temperature dilatometer show that the phase transitions of SrZrO3 is suppressed remarkably by co-doping Y2O3 and Gd2O3. The thermal conductivity of bulk SZYG at 10001 is 1.36 W/(mK), which is 35% lower than that of bulk SrZrO3 and 8YSZ. The good chemical compatibility of SZYG with 8YSZ and A12O3, is detected after heat-treatment at 1250°C for 24 h.%采用固相反应法合成了5mol% Y2O3与5mol% Gd2O3共掺杂SrZrO3(Sr(Zr0.9Y0.05Gd0.05)O2.95,SZYG)粉末.采用X射线衍射(XRD)和差示扫描量热仪(DSC)分别研究了SZYG粉末在1450℃长期热处理后以及200~1400℃范围内的相稳定性.采用高温热膨胀仪测量了SZYG块材的热膨胀系数,结果表明:通过Y2O3与Gd2O3共掺杂改性可以明显抑制SrZrO3的相转变.在1000℃下SZYG块材的热导率是~1.36 W/(m.K),与SrZrO3和8YSZ块材相比降低~35% SZYG分别与8YSZ和Al2O3在1250℃热处理24h表现出很好的化学相容性.

  5. Processing and Characterization of In-Situ Generated Nanosilver and Er3+ Co-Doped Bromoborosilicate Glass Nanocomposites.

    Sarkar, Jit; Tarafder, Anal; Karmakar, Basudeb


    In the present investigation, bromoborosilicate glass of composition 6Na2O-19K2O-10BaBr2- 2Al2O3-15B2O3-48SiO2 (mole %) added with 0.2 wt% SnO, co-doped with 0.001 wt% Ag and 0.7 wt% Er2O3 in excess amount, was prepared by melt-quench technique. The metal-glass nanocomposites were derived involving a single-step in-situ thermochemical reduction of the precursor glass subjecting an isothermal heat-treatment protocol. The precursor glass and metal glass nanocomposites were characterized by dilatometer, differential scanning calorimeter, X-ray diffractometer, field emission scanning electron microscope, transmission electron microscope, Fourier transform infrared spectrometer, UV-Vis-NIR spectrophotometer, fluorimeter etc. XRD spectra represent the amorphous nature of the samples and without having any sharp peaks of silver (Ag0) and barium bromide (BaBr2). But the FESEM micrograph shows the presence of BaBr2 crystallites in clusters and the TEM micrograph shows the presence of AgO nanoparticles of different shapes and sizes. The precursor glass sample shows sharp absorption peak at 378 nm and 521 nm due to the 4G11,2 and 2H11/2 energy levels of Er3+ but glass nanocomposites exhibit another band at 410 nm due to the surface plasmon resonance of Ag0 nanoparticles. They also show sharp emis- sion peak at 1542 nm due to 4115/2 -+4l13/2 transition of Er3+ ions and prominent upconverted peaks at 630 nm (red, medium) and 645 nm (red, strong) due to 4F9/2 + 1 15/2 transition. The intensity of the absorption and upconverted peaks increases with the duration of heat treatment, having maximum intensity at 5 h and the intensity of the emission peak increases with heat treatment upto 1 h and then decreases for 5 h. Thus these metal-glass nanocomposites show enhanced photoluminescence upconversion and are promising material for different photonic applications.

  6. Influence of Glass Components on Chromaticity and Properties of Green Glass-Ceramics%基础成分对绿色微晶玻璃色度及性能的影响

    姜妍彦; 李振全; 王世凯; 刁云超


    以CaO-Al2O3-SiO2玻璃为基础,以CuO+Cr2O3为着色剂,通过烧结法制备了绿色微晶玻璃,采用X射线衍射、扫描电子显微镜、色度计、熟膨胀仪和硬度计研究了Al2O3、Na2O和ZnO含量对绿色微晶玻璃晶相结构、色度及性能的影响.结果表明:在所研究的成分范围内,Al2O3、ZnO和Na2O含量的变化不改变绿色微晶玻璃的主晶相,但随着Al2O3加入量的增加微晶相减少,熟膨胀系数和密度减小,显微硬度增大,颜色向褐绿色转变;随着Na2O含量的增加,微晶玻璃的颜色逐渐纯正,光泽度增加;随着ZnO含量的增加,微晶玻璃的色度不变,但表面光泽度降低.%Green glass-ceramics were prepared by sintering method based on CaO-Al2O3-SiO2 system glass, using CuO+Cr2O3 as colorants. Impact of the contents of A12O3, Na2O and ZnO in green glass-ceramics on crystal structure, chromaticity and properties was studied via X-ray diffraction, scanning electron microscope, colorimeter, dilatometer and hardness tester. The results indicate that the main crystal phase of green glass-ceramics doesn't change with the contents of A12O3, Na2O or ZnO in the range of the composition, but the microcrystalline phase, the thermal expansion coefficient decrease, micro-hardness increase, the color changes from bright green to brownish-green with the increasing of A12O3. The color of glass-ceramics gradually becomes bright green and the surface glossiness increases with the increasing of Na2O. The chromaticity of glass-ceramics doesn't change, but the surface glossiness decrease with the increasing of ZnO.

  7. Effect of Carbon Distribution During the Microstructure Evolution of Dual-Phase Steels Studied Using Cellular Automata, Genetic Algorithms, and Experimental Strategies

    Halder, Chandan; Karmakar, Anish; Hasan, Sk. Md.; Chakrabarti, Debalay; Pietrzyk, Maciej; Chakraborti, Nirupam


    The development of ferrite-martensite dual-phase microstructures by cold-rolling and intercritical annealing of 0.06 wt pct carbon steel was systematically studied using a dilatometer for two different heating rates (1 and 10 K/s). A step quenching treatment has been designed to develop dual-phase structures having a similar martensite fraction for two different heating rates. An increase in heating rate seemed to refine the ferrite grain size, but it increased the size and spacing of the martensitic regions. As a result, the strength of the steel increased with heating rate; however, the formability was affected. It has been concluded that the distribution of C during the annealing treatment of cold-rolled steel determines the size, distribution, and morphology of martensite, which ultimately influences the mechanical properties. Experimental detection of carbon distribution in austenite is difficult during annealing of the cold-rolled steel as the phase transformation occurs at a high temperature and C is an interstitial solute, which diffuses fast at that temperature. Therefore, a cellular automata (CA)-based phase transformation model is proposed in the present study for the prediction of C distribution in austenite during annealing of steel as the function of C content and heating rate. The CA model predicts that the carbon distribution in austenite becomes more inhomogeneous when the heating rate increases. In the CA model, the extent of carbon inhomogeneity is measured using a kernel averaging method for different orders of neighbors, which accounts for the different physical space during calculation. The obtained results reveal that the 10th order (covering 10- µm physical spaces around the cell of interest) is showing the maximum inhomogeneity of carbon and the same effect has been investigated and confirmed using auger electron spectroscopy (AES) for 0.06 wt pct carbon steel. Furthermore, the optimization of carbon homogeneity with respect to heating

  8. Signature of magmatic processes in ground deformation signals from Phlegraean Fields (Italy)

    Bagagli, Matteo; Montagna, Chiara Paola; Longo, Antonella; Papale, Paolo


    Ground deformation signals such as dilatometric and tiltmetric ones, are nowadays well studied from the vulcanological community all over the world. These signals can be used to retrieve information on volcanoes state and to study the magma dynamics in their plumbing system. We compared synthetic signals in the Very Long Period (VLP, 10-2 - 10-1 Hz) and Ultra Long Period (ULP, 10-4 - 10-2 Hz) bands obtained from the simulation of magma mixing in shallow reservoirs ([3],[4]) with real data obtained from the dilatometers and tiltmeters network situated in the Phlegraean Fields near Naples (Italy), in order to define and constrain the relationships between them. Analyses of data from the October 2006 seismic swarm in the area show that the frequency spectrum of the synthetics is remarkably similar to the transient present in the real signals. In depth studies with accurated techniques for spectral analysis (i.e wavelet transform) and application of this method to other time windows have identified in the bandwidth around 10-4Hz (between 1h30m and 2h45m) peaks that are fairly stable and independent from the processing carried out on the full-band signal. These peaks could be the signature of ongoing convection at depth. It is well known that re-injection of juvenile magmas can reactivate the eruption dynamics ([1],[2]), thus being able to define mixing markers and detect them in the ground deformation signals is a relevant topic in order to understand the dynamics of active and quiescent vulcanoes and to eventually improve early-warning methods for impending eruptions. [1] Arienzo, I. et al. (2010). "The feeding system of Agnano-Monte Spina eruption (Campi Flegrei, Italy): dragging the past into present activity and future scenarios". In: Chemical Geology 270.1, pp. 135-147. [2] Bachmann, Olivier and George Bergantz (2008). "The magma reservoirs that feed supereruptions". In: Elements 4.1, pp. 17-21. [3] Longo, Antonella et al. (2012). "Magma convection and mixing

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

    Schwaighofer, Emanuel, E-mail: [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)


    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

  10. Determination of consolidation coefficient for soft clay from DMTC dissipation tests%DMTC消散试验探求软黏土固结系数研究



    Based on the flat dilatometer test (DMT) theory, the method for deriving the coefficient of horizontal consolidation from DMTC dissipation tests is introduced. The DMTC test results of saturated soft clay ground in Shangqiu-Hefei-Hangzhou railway and Shanghai-Nantong railway are presented, and the coefficient of horizontal consolidation is obtained from the DMTC dissipation data. The results of the coefficient of horizontal consolidation are compared with CPTU dissipation test data and laboratory odometer test data. The comparison shows that the coefficients of horizontal consolidation determined by DMTC tests and CPTU tests are very close. The correlation is good for homogeneous soil, but bad for non-homogeneous soil. The coefficients of horizontal consolidation from laboratory odometer tests are smaller than those obtained by DMTC and CPTU tests, as reported by other researchers.%基于扁铲侧胀试验(DMT)的基本原理,简要地介绍了利用DMT的C值消散试验求解水平向固结系数的理论与方法。结合商丘—合肥—杭州(商合杭)铁路工程湖州试验段与上海—南通(沪通)铁路工程常熟试验段的DMTC消散试验进行了实例分析研究。结果表明:DMTC消散试验与孔压静探消散试验获取水平向固结系数较为接近,二者在均质土层中相关性较好,在非均质土层中相关性较差;与DMTC消散试验及孔压静探消散试验获取的水平向固结系数相比,室内试验获取的水平向固结系数明显偏小,与其他研究者的成果一致。

  11. Long Valley Deep Hole Geophysical Observatory --- Strain Instrumentation and Installation.

    Sacks, S. I.; Linde, A.; Malin, P.; Roeloffs, E. A.; Hill, D. P.; Ellsworth, W. L.


    The Long Valley Exploratory Well, drilled in the middle of the resurgent dome in the Long Valley caldera, was started in 1989 and after rather checkered progress eventually reached a depth of about 9,831 feet. The hole is cased to a depth of 7178 feet with bare rock below that. At 8,500 feet there is an open fracture system with substantial permeability. One of the goals of the instrument installation is to enable monitoring of this deep aquifer. The most satisfactory rock away from obvious large fractures was at about 7,400 feet, and this was the installation depth. The instrumentation package consisted of a bottom hole seismometer at a depth of about 8500 feet, and a coupled instrument string that was cemented to the rock at a depth of 7400 feet. The instrument string, 73 feet long, had an inflatable packer with an extension at the bottom, coupled to a seismometer with a cement exit port above it, a 22 foot long spacing tube connected to a 20 foot long sensing volume strainmeter assembly. The strainmeter unit is essentially an annulus with the cementing pipe passing through it. In addition, two seismometer cables, two water bypass tubes and a packer inflation tube, pass through the strainmeter, which is actually two concentric strainmeters. The outer unit is a dilatometer and the inner unit is a vertical component strainmeter. Before installation, the strainmeters and the 8000 foot long stainless steel coupling tubes were filled with filtered and degassed water. The instrument string and attached bottom hole seismometer were then lowered down the hole attached to drill pipe. Two optical fiber vertical strainmeters (one interferometer and one time-of-flight loop) consisting of three fibers were attached to the drill pipe as it was installed. After the drill pipe reached target depth, it was secured to the well head. The packer, at the bottom of the instrument package, was inflated, thus providing a sealed bottom for the cement. Cement was then pumped down the

  12. Thermodynamic studies at the low-dimensional spin systems HP-(VO){sub 2}P{sub 2}O{sub 7}, SrCu{sub 2}(BO{sub 3}){sub 2}, and azurite; Thermodynamische Untersuchungen an den niedrigdimensionalen Spinsystemen HP-(VO){sub 2}P{sub 2}O{sub 7}, SrCu{sub 2}(BO{sub 3}){sub 2} und Azurit

    Bruehl, Andreas


    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){sub 2}P{sub 2}O{sub 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{sub 2}(BO{sub 3}){sub 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 {lambda}-shaped antiferromagnetic order transition was studied and the phase diagram, consisting of

  13. Complex modification of secondary silumins

    A. A. Mityayev


    Full Text Available Purpose. Development of scientific and technological bases of formation of the specified secondary hypoeutectic (АK8M3 and eutectic (АК12М2MgН silumins' structure; and increasing their mechanical and service properties' indices in the cast state and after heat treatment up to the level of primary alloys. Methodology. Determination of the chemical composition was conducted by spectral analysis on the spark spectrometer «SPECTROLAB» (Germany. Metallographic analysis was performed on the microscopes МIМ-7 and МIМ-8, and also by the high definition metallography method using the raster electronic microscope «JSMT-300» (Japan. Heat treatment of aluminum alloys was carried out applying T1 and T5 modes according to State Standard of Ukraine 2839-94 (GOST 1583-93. Standard techniques were used during the determination of mechanical properties. The temperature coefficient of linear expansion for the piston alloy АK12М2МgH (AL25 was determined using the specimens Ø with the diameter of 3.5 mm and length of 50 mm with the use of Shevenard optical quartz dilatometer. High temperature fracture resistance was determined according to State Standard 10145-81 as the time before fracture of the specimen at specified stress of 50 MPa and temperature of 300°С. Findings. The technology of obtaining alloys from charge, which consists of 100 % scrap and production wastes has been developed and implemented into production. This technology provides obtaining of metal of the guaranteed chemical composition and high quality with the reduction of energy costs for melting. Originality. The regularities of the formation of the structural and phase state and the level of physical and mechanical properties of eutectic and secondary hypoeutectic silumins depending on the refining and modifying processes have been established. The generalization of regularities of the secondary silumins' fracture has been carried out. Quantitative characteristics of the

  14. Microstructure and mechanical properties of a 15 % Cr supermartensitic stainless steel microalloyed with tungsten%含W的Cr15型超级马氏体不锈钢组织性能分析

    业冬; 李俊; 姜雯; 苏杰; 赵昆渝


    The microstructure and mechanical properties of a 15%Cr super martensitic stainless steel microalloyed with tungsten were investigated by means of dilatometer, optical microscopy, transmission electron microscopy (TEM) , high-resolution transmission electron microscopy ( HRTEM ) , energy dispersive spectrometer ( EDS), and tensile and hardness tests. The results revealed that a typical biphase structure of tempered martensite and reversed austenite which diffusional distributed in martensite matrix was selected after quenching and tempering. The reversed austenite and martensite matrix meet the K-S relationship. The diffraction pattern calculations and the EDS analysis of TEM confirmed that the nanometer-sized Laves particles and rich copper phase ε-Cu precipitated in the matrix during tempering in the investigated steel, which were contributive to improve strength. The steel microalloyed with W showed an improved mechanical property values: 26 ~ 36 RC hardness, 895 ~ 1 009 MPa tensile strength, 17% ~21% elongation.%采用全自动热膨胀相变仪、光学显微镜、透射电镜、高分辨电镜及能谱分析和力学万能试验机等手段,研究含W的Cr15型超级马氏体不锈钢经淬火+回火后的微观组织和力学性能.结果表明,淬火+回火后的微观组织为回火马氏体及分布在马氏体基体中的逆变奥氏体两相组织,形成的逆变奥氏体与马氏体板条符合K-S关系.在基体上弥散析出的纳米级金属化合物Laves相以及富铜相ε-Cu起到强化作用.该钢具有优良的力学性能,洛氏硬度为26~36,抗拉强度为895~1 009 MPa,延伸率为17% ~21%.

  15. ZrO2复合A12O3基陶瓷的抗热震性能%Thermal Shock Resistance of A12O3/ZrO2 Ceramics

    张寒; 赵惠忠; 陈金凤; 余俊; 聂建华


    By adding zirconia to alumina ceramic matrix composites at different levels of 0. 75wt. %, 1. 5wt. %, 2.25wt. % and 3wt. %, the influences on sintering performance, thermal expansion property and thermal conductivity were systematically investigated. Using the SEM, High-temperature dilatometer and Laserflash thermal analyzer, etc, the property characterization of the samples was conducted. According to the results, the ascending additions of zirconia increase the apparent porosity and decrease the bulk density; the thermal conductivity is exponentially descending; thermal expansion coefficient follows a sinusoidal trend, of which the sample of zirconia betweenl. 5wt. % and 2. 0wt. % is the least. It is manifested that application of zirconia can improve the thermal shock resistance of alumina ceramic matrix composites.%将氧化锆添加到氧化铝基陶瓷中,系统研究了其加入量(外加质量分数分别为0.75%、1.5%、2.25%和3%)对试样烧结性能、高温膨胀性能及导热性能的影响.通过高温立式热膨胀仪、激光导热仪等分析测试技术对试样进行了性能表征,结果表明:随着氧化锆加入量的增大,试样的显气孔率增大,体积密度减小;试样的导热系数随氧化锆的加入呈指数衰减,导热性能降低;其热膨胀系数呈正弦曲线变化,wt(ZrO2)%为1.5%~2.0%的试样热膨胀系数最小.氧化锆的引入,可改善氧化铝基陶瓷材料的抗热震性能.

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

    Mohd Idzat Idris


    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

  17. Thermal Expansion and Magnetostriction of CeCu{sub 6-x}Au{sub x} at low temperatures; Thermische Ausdehnung und Magnetostriktion von CeCu{sub 6-x}Au{sub x} bei sehr tiefen Temperaturen

    Drobnik, Stefanie


    A well-studied magnetic quantum critical point (QCP) exists at the onset of antiferromagnetic order in the heavy-fermion system CeCu{sub 6-x}Au{sub x} with a critical gold concentration of x{sub c}{approx}0.1. Due to the instability at the QCP the entropy S shows at finite temperatures a maximum as a function of x, volume V, or pressure p. The maximum leads to a sign change of the thermal expansion coefficient, {alpha}=-(1/V)({partial_derivative}S/{partial_derivative}p), and of the Grueneisen parameter {gamma}, the ratio of {alpha} and specific heat. This feature and the divergence of {gamma} at T{yields}0 are important thermodynamic probes to detect and classify QCPs. This work describes the set-up of a high-resolution dilatometer in a {sup 3}He/{sup 4}He dilution refrigerator and reports low-temperature thermal expansion and magnetostriction measurements on the critical concentration x=0.1 and x=0.15 with a Neel temperature of T{sub N}{approx}89 mK. The thermal expansion was measured in a temperature range of 30 mK

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

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


    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

  19. Preparation of Cristobalite-based Ceramics Using the Discarded Quartz Crucible%废弃石英坩埚资源化制备方石英质瓷

    孙健; 李家科; 王艳香; 朱海翔


    Cristobalite-based ceramics were prepared using the discarded quartz crucible , kaolin, feldspar and bauxite as raw materials .The effects of batch formula and firing temperature on phase composition , microstructure , coefficient of thermal expansion and mechanical performances of cristobalite-based ceramics were investigated by XRD , SEM, thermal dilatometer and material testing machine .The results show that cristobalite-based ceramics with good mechanical performances are obtained when discarded quartz crucible 40%, kaolin 40%, feldspar 15% and bauxite 5% at 1300 ℃ for 30 min .Bending strength and coefficient of thermal expansion of cristobalite-based ceramic are 76.45 MPa and 7.16 × 10 -6℃-1 ( RT~600 ℃) ,respectively .And thermal shock resistance (△T ) is above 180 ℃.%以废弃石英坩埚、苏州土、长石和铝矾土等为原料制备方石英质瓷。采用XRD、SEM、热膨胀仪和材料试验机等测试方法,研究了配方组成和烧成温度对方石英质瓷的物相组成、微观形貌和机械性能影响规律。结果表明:当配料配方中废弃石英坩埚40%、苏州土40%、钾长石15%和铝矾土5%,在烧成温度1300℃、保温时间30 min条件下,可以获得机械性能较佳的方石英质瓷,其弯曲强度为76.45 MPa,热稳定性△T ≥180℃,热膨胀系数为7.16×10-6℃-1( RT~600℃)。

  20. Thermal expansion and magnetostriction studies on iron pnictides

    Wang, Liran


    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

  1. Effects of zirconium oxide on the sintering of SrCe{sub 1−x}Zr{sub x}O{sub 3−δ} (0.0 ≦ x ≦ 0.5)

    Hsu, Kai-Ti, E-mail: [Institute of Materials Science and Engineering, National Central University, Taoyuan 32001, Taiwan, ROC (China); Jang, Jason Shian-Ching, E-mail: [Institute of Materials Science and Engineering, National Central University, Taoyuan 32001, Taiwan, ROC (China); Department of Mechanical Engineering, National Central University, Taoyuan 32001, Taiwan, ROC (China); Ren, Yu-Jing; Tsai, Pei-Hua [Institute of Materials Science and Engineering, National Central University, Taoyuan 32001, Taiwan, ROC (China); Li, Chuan; Tseng, Chung-Jen [Department of Mechanical Engineering, National Central University, Taoyuan 32001, Taiwan, ROC (China); Lin, Jing-Chie [Institute of Materials Science and Engineering, National Central University, Taoyuan 32001, Taiwan, ROC (China); Hsi, Chi-Shiung [Department of Materials Science and Engineering, National United University, Miaoli 36003, Taiwan, ROC (China); Hung, I-Ming [Department of Chemical Engineering and Materials Science, Yuan-Ze University, Taoyuan 32003, Taiwan, ROC (China)


    Graphical abstract: SEM cross-sectional microstructures of (a) the HTM with multilayer-supported structure sintered at 1550 °C for 4 h; the sequence of distinct layer is SrCeO{sub 3}, SrCe{sub 0.6}Zr{sub 0.4}O{sub 3-δ}, and SrZrO{sub 3} from the middle to the outer surface. (b) Enlaged image from circle A in Fig. 7(a). (c) Enlarged image from circle B in Fig. 7(a). - Highlights: • The sinterability of SrCe{sub 1-x}Zr{sub x}O{sub 3-δ} (0.0 ≦ x ≦ 0.5) oxides decreased with increasing Zr contents. • The porosities of sintered SrCe{sub 1-x}Zr{sub x}O{sub 3-δ}(0.0 ≦ x ≦ 0.5) oxides increased with increasing Zr contents. • SrCe{sub 0.6}Zr{sub 0.4}O{sub 3-δ} ceramics sintered at 1500 °C has the largest porosity in the SrCe{sub 1-x}Zr{sub x}O{sub 3-δ}(0.0 ≦ x ≦ 0.5) ceramics system. • A flat HTM with porous supporting layers was fabricated by constrained sintering. - Abstract: SrCe{sub 1−x}Zr{sub x}O{sub 3−δ} (0.0 ≦ x ≦ 0.5) proton-conducting oxides had been successfully prepared using a solid state reaction method. In this study, the relationships between the Zr contents and microstructures, shrinkages, and sintering of these SrCe{sub 1−x}Zr{sub x}O{sub 3−δ} (0.0 ≦ x ≦ 0.5) were systemically studied by using X-ray Diffraction, Scanning Electron Microscopy, and Thermal dilatometer analysis (TDA). The XRD results showed that no second phase could be found from the 1500 °C sintered SrCe{sub 1−x}Zr{sub x}O{sub 3−δ}. The SEMs shows that the porosities of sintered SrCe{sub 1−x}Zr{sub x}O{sub 3−δ} increased with increasing the Zr contents. The largest porosity about 27.53% could be obtained at the SrCe{sub 0.6}Zr{sub 0.4}O{sub 3−δ} ceramics sintered at 1500 °C for 2 h in the SrCe{sub 1−x}Zr{sub x}O{sub 3−δ} ceramics. According to the sintering behaviour and properties characterizations, a flat HTM with porous supporting layers of SrCe{sub 0.6}Zr{sub 0.4}O{sub 3−δ} and SrZrO{sub 3} was fabricated by constrained

  2. Ferritas Ni-Zn: síntese por reação de combustão e sinterização Ni-Zn ferrites: combustion reaction synthesis and sintering

    A. C. F. M. Costa


    Full Text Available Este trabalho apresenta o estudo da síntese por reação de combustão e sinterização de pós nanométricos de ferritas Ni-Zn. O efeito da concentração de Zn2+ no sistema Ni1-xZn xFe2O4 foi investigado. Os pós resultantes da combustão foram caracterizados por DRX, BET, MEV, picnometria de hélio e sedimentação (Horiba. Em seguida foram prensados uniaxialmente e sinterizados com taxa constante de aquecimento (TCA de 5,0 ºC/min de 600 ºC até a temperatura de 1200 ºC, em um dilatômetro horizontal. Os compactos foram caracterizados por microscopia eletrônica de varredura. Os resultados mostram que foi possível obter pós de ferritas Ni-Zn com tamanho de partícula entre 18 - 27 nm usando a síntese por reação de combustão. Durante sinterização dos pós nanométricos observou-se três estágios distintos, os quais foram identificados através da Teoria de Bannister. A adição do Zn2+ não modificou o mecanismo de sinterização nos três estágios. Para os estágios inicial e final o mecanismo predominante foi por fluxo viscoso, atribuído ao rearranjo estrutural das nanopartículas e para o estágio intermediário foi difusão volumétrica.This work presents the study of the synthesis for combustion reaction and sintering of Ni-Zn nanometric ferrite powders. The effect of the concentration of Zn2+ in the system Ni1-xZn xFe2O4 was investigated. The resulting powders of the combustion were characterized by DRX, BET, MEV, picnometry of helium and sedimentation (Horiba. Uniaxially pressed samples were sintered with constant heating rate (TCA of 5.0 ºC/min from 600 ºC to the temperature of 1200 ºC, in a horizontal dilatometer. The compact ones were characterized by scanning electron microscopy. The results show that was possible to obtain Ni-Zn ferrite powders with particle size among 18 - 27 nm using combustion reaction synthesis. During sintering of the nanometric powders it was observed three different stages, which were

  3. Obtención de espumas a partir de residuos de pizarra

    Cambronero, L. E. G.


    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

  4. New inferences from spectral seismic energy measurement of a link between regional seismicity and volcanic activity at Mt. Etna, Italy

    Ortiz, R.; Falsaperla, S.; Marrero, J. M.; Messina, A.


    earthquakes. It can be interpreted as the magmatic response to a change of the distribution of tectonic stress in the edifice before the earthquake. In the light of this hypothesis, we surmise that the magmatic system behaved similar to a dilatometer and promise news lines to forecasting the volcano activity. References M. Tárraga, R. Carniel, R. Ortiz, J. M. Marrero, and A. García, 2006. On the predictability of volcano.tectonic events by low frequency seismic noise analysis at Teide-Pico Viejo volcanic complex, Canary Islands. Nat. Hazards Earth Syst. Sci., 6, 365-376. Ortiz, R., H. Moreno, A. García, G. Fuentealba, M. Astiz, P. Peña, N. Sánchez, M. Tárraga, 2003. Villarrica volcano (Chile): characteristics of the volcanic tremor and forecasting of small explosions by means of a material failure method. J. Volcanol. Geotherm. Res. 128: 247-259. B. Voight, 1988. A method for prediction of volcanic eruptions. Nature 332, 10:125-130.

  5. Water-level changes induced by local and distant earthquakes at Long Valley caldera, California

    Roeloffs, E.; Sneed, M.; Galloway, D.L.; Sorey, M.L.; Farrar, C.D.; Howle, J.F.; Hughes, J.


    Distant as well as local earthquakes have induced groundwater-level changes persisting for days to weeks at Long Valley caldera, California. Four wells open to formations as deep as 300 m have responded to 16 earthquakes, and responses to two earthquakes in the 3-km-deep Long Valley Exploratory Well (LVEW) show that these changes are not limited to weathered or unconsolidated near-surface rocks. All five wells exhibit water-level variations in response to earth tides, indicating they can be used as low-resolution strainmeters. Earthquakes induce gradual water-level changes that increase in amplitude for as long as 30 days, then return more slowly to pre-earthquake levels. The gradual water-level changes are always drops at wells LKT, LVEW, and CH-10B, and always rises at well CW-3. At a dilatometer just outside the caldera, earthquake-induced strain responses consist of either a step followed by a contractional strain-rate increase, or a transient contractional signal that reaches a maximum in about seven days and then returns toward the pre-earthquake value. The sizes of the gradual water-level changes generally increase with earthquake magnitude and decrease with hypocentral distance. Local earthquakes in Long Valley produce coseismic water-level steps; otherwise the responses to local earthquakes and distant earthquakes are indistinguishable. In particular, water-level and strain changes in Long Valley following the 1992 M7.3 Landers earthquake, 450 km distant, closely resemble those initiated by a M4.9 local earthquake on November 22, 1997, during a seismic swarm with features indicative of fluid involvement. At the LKT well, many of the response time histories are identical for 20 days after each earthquake, and can be matched by a theoretical solution giving the pore pressure as a function of time due to diffusion of a nearby, instantaneous, pressure drop. Such pressure drops could be produced by accelerated inflation of the resurgent dome by amounts too

  6. Effect of FeAl2O4 on properties of periclase-hercynite refractories%FeAl2O4对方镁石-铁铝尖晶石质耐火材料性能的影响

    周芬; 赵惠忠; 王立峰; 慕松林; 崔江涛; 吕永峰


    以高纯镁砂(5~2、≤2和≤0.088 mm)、电熔铁铝尖晶石(3~1和≤0.088 mm)为原料,亚硫酸纸浆废液为结合剂,配料混练后机压成型为36 mm ×36 mm及25 mm ×25 mm ×140 mm的试样,经110℃24 h烘干,然后于1650℃3 h热处理。采用热膨胀仪、弹性模量仪、SEM等对试样进行了分析研究,分别研究了FeAl2 O4粒度(3~1或≤0.088 mm)及加入量(质量分数为0、2%、4%、6%、8%、10%、12%)对方镁石-铁铝尖晶石质耐火材料性能的影响。结果表明:随着FeAl2 O4添加量的增加,试样的常温强度、线膨胀系数、弹性模量降低。FeAl2 O4以细粉形式加入时,试样的常温强度、弹性模量比以颗粒形式加入的要大;加入约4%(w)FeAl2 O4就能明显改善镁质制品的抗热震性,其抗热震提高的机制以微裂纹增韧为主;固定尖晶石加入量为8%(w),尖晶石以细粉形式加入时,试样中FeAl2 O4可完全反应为(Mg,Fe)Al2 O4,以颗粒形式加入时,仅会在颗粒周围生成少量(Mg,Fe)Al2 O4。%Periclase-hercynite specimens with sizes of36 mm ×36 mm and 25 mm ×25 mm ×140 mm were prepared using high purity magnesia(5 -2,≤2,≤0.088 mm)and fused hercynite(3-1 ,≤0.088 mm)as starting materials,and lignosulfite as binder,batching,mixing,pressing,drying at 1 10 ℃ for 24 h,and then firing at 1 650 ℃ for 3 h.Effects of particle sizes (3-1,≤0.088 mm)and additions (0,2%,4%,6%,8%, 10%,12% in mass)of hercynite on properties of periclase-hercynite bricks were investigated by a thermo-dilatometer,an elasticity modulus tester,etc.The more the added hercynite,the lower the cold strength, the thermal expansion coefficient and the elasticity modulus of periclase-hercynite refractories.The speci-mens with hercynite powder have higher cold strength and elasticity modulus than those with hercynite par-ticles.The thermal shock resistance is improved obviously

  7. Ferrite transformation kinetics of X70 pipeline steel during continuous cooling%连续冷却过程中 X70管线钢的铁素体相变动力学

    谢保盛; 蔡庆伍; 余伟; 曹嘉明; 杨云峰


    Thermal expansion curves of X 70 pipeline steel during continuous cooling process were tested on DIL 805 dilatometer .Based on experimental results , the start temperature of austenite to ferrite transformation among two models were analyzed , and the key parameters of ferrite transformation were obtained by reverse regression method with the JMAK equation , thus the kinetics during continuous cooling process were determined.The results show that, the optimal n and k can be obtained by the method mentioned above .In models, n is set as 0.5, 1, 1.5, 1-0.5X2 respectively to calculate the transformation kinetics , where X represents transformation volume fraction .In terms of n value characterized by 1-0.5X2 , it is higher precision and in better agreement with the experimental data than n value set as 0.5, 1, 1.5.In modelⅠ, the predicted results are deviated under high cooling rate , which results from the limitation of ferrite nucleation energy ΔGV . However , while modelⅡjust including two parameters is more availability .To X70 pipeline steel , the relationship between start temperature of ferrite transformation and cooling rate is indicated as Ts=Ae3 -39.1440φ0.4020 .%在DIL805膨胀仪上测量了X70管线钢在连续冷却过程中的热膨胀曲线。根据试验结果,分析比较了两种奥氏体-铁素体相变开始温度模型,并通过对JMAK方程采用逆向回归法确定了铁素体相变分数的关键性参数,从而确定了连续冷却过程中的相变动力学。结果表明,不同冷却速率下的最佳n值和k值可通过JKMA公式逆向回归得出,模型分别采用时间指数n为0.5、1、1.5、1-0.5X2的4种取值方法计算铁素体相变动力学曲线,通过与试验数据的对比发现,用相变体积分数X的函数表征n值的方法计算精度更高,与试验结果吻合更好。模型Ⅰ由于对铁素体体积形核功ΔGV的取值有局限性,使得模型在大冷却速率下的预测结果

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

    Orgaz, Felipe


    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

  9. MARSite-MARMARA SUPERSITE: Accomplishments and Outlook

    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


    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

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

    S. M. Tebcheran


    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.

  11. 新型复合阴极 Sr0.95Ti0.05Co0.95O3-δ-Sm0.2Ce0.8O1.9在中低温固体氧化物燃料电池中的性能%Performance of Composite Cathode Sr0.95Ti0.05Co0.95O3-δ-Sm0.2Ce0.8O1.9 Used in Intermediate Temperature SOFCs

    余良浩; 王晓晴; 林彬; 田冬; 卢肖永; 顾庆文; 陈永红


    A cathode powder of Sr0.95Ti0.05Co0.95O3−δ(STC) and an electrolyte powder of Sm0.2Ce0.8O1.9 (SDC) were synthesized by a citric acid-nitrates self-propagating combustion method. The composite-cathode was obtained by mixing the STC and SDC powders in a mass ratio of 7:3. The chemical compatibility, electrical conductivity and thermal expansion coefficient of the composite cathode were characterized by X-ray diffraction(XRD), direct current four-terminal method and thermal dilatometer, respectively. The XRD results show that a pure cubic STC perovskite phase can be obtained at 900 and℃ no second phase is formed in the composite cathode at the operating temperature. The polarization resistance of the electrode is only 0.05 Ω·cm2 at 650 ℃. The anode-supported solid oxide fuel cells of NiO-SDC│SDC│STC−SDC were fabricated. The electrochemical performances were examined at 450−650 ℃ with humidified hydrogen (about 3% H2O) as a fuel and air as an oxidant. It is demonstrated that the anode-supported half cells can be sintered at 1 350 with a dense electrolyte layer and porous℃ electrodes, and the single cell with an open circuit voltage of 0.82 V and the maximum power density of 721 mW/cm2 at 650 ℃ can be obtained. These results indicate that STC−SDC is a promising composite cathode candidate for IT-SOFC with SDC electrolyte.%采用柠檬酸自蔓延燃烧法合成了 Sr0.95Ti0.05Co0.95O3−δ(STC)阴极粉体和 Sm0.2Ce0.8O1.9(SDC)电解质粉体,将 STC 与SDC 粉体按质量比7:3混合得到复合阴极。通过 X 射线衍射(XRD)、直流四端子法和热膨胀仪表征了样品的化学相容性、电导率和热膨胀系数。XRD 表明,STC 在900℃能够得到立方纯钙钛矿结构,复合阴极 STC−SDC 在工作温度区间内具有很好的化学相容性;在650℃空气气氛下 STC−SDC 与 SDC 之间的界面极化阻抗仅为0.05Ω·cm2。制备了阳极支持型(NiO-SDC│SDC│STC−SDC)单电池,在450~650