[en] The French atomic energy commission (CEA) and Garlock company have developed a new gasket technology which can stand temperatures up to 1000 deg. C and pressures up to 100 bars. This gasket, named Ultraseal, is of 'metal-metal' type. It comprises an expanded graphite ring between two metal cupels and inside a metal envelope. The first application concerns the nuclear industry but also the aerospace and chemical industries. Short paper. (J.S.)

[en] The typical heat-resisting rotor steels such as 2.25CrMo, 9CrMo and 12CrW steel were experimentally studied in order to understand their materials degradation under high temperature and pressure during the long-term service, and then use the basic studies for the structural health monitoring. In order to monitor the materials degradation, it was conducted by the isothermal aging for 2.25CrMo steel, creep-fatigue for 9CrMo steel and creep for 12Cr steel with the incremental step test. The ultrasonic wave properties, electrical resistivity and coercivity were interpreted in relation to microstructural changes at each material and showed strong sensitivity to the specific microstructural evolution

[en] This volume contains 17 lectures on the following subjects (selection): Microstructural description of the creep behaviour of the Ni-based superalloy IN 738 LC based on the iso-structural model; the effect of Nb, V, N and Al on the creep rupture strength of 9-12% Cr steels; structure and long-time investigations of 9-12% Cr steels for forged and cast parts; creep tests on samples of welded pipe joints made of X10CrMo V Nb 9-1 steel, evolution of the microstructure during creep stress and annealing of the Martensitic cast steel G-X12 Cr Mo V Nb N 9 1; Micro-structure during cyclic creep in the creep area using the example of Martensitic steel X22 Cr Mo V 12 1; description of crack initiation and progress of hot cracks in heat resisting 1% Cr Mo V castings under creep or fatigue stress; optimisation and verification of creep equations for high temperature materials, single stage and multi-stage long-time creep fatigue behaviour of heat-resistant steels; cyclic creep behaviour of heat-resistant steels under intermittent stress and on the tension/compression area. (orig./MM)

[en] The four kinds of Al₂O₃ composite ceramics were prepared using a mixture of 85 wt.% Al₂O₃ (mean size 0.5 μm), 15 wt.% SiC powder with Y₂O₃ as an additive powder (0, 1, 3 and 5 wt.%). The crack-healing strengths were studied as functions of crack-healing temperature and amount of Y₂O₃. The in-situ crack-healing behavior was observed at 1,573 K for 1 h in the air. The heat treated specimen with 3 wt.% of Y₂O₃ showed better crack-healing ability than specimen with 1 or 5 wt.% of Y₂O₃. In case of specimen with 3 wt.% of Y₂O₃, the bending strength of the crack-healed specimen at 1,473 K was recovered to the bending strength of smooth specimen treated at 1573 K. The heat-resistance limit temperature of Al₂O₃ composite ceramics was 1,073 K, 1,373 K, 873 K for the specimen with 1, 3, 5 wt.% of Y₂O₃

[en] The High Temperature Materials Laboratory (HTML) is designed to assist American industries, universities, and governmental agencies develop advanced materials by providing a skilled staff and numerous sophisticated, often one-of-a-kind pieces of materials characterization equipment. It is a nationally designated user facility sponsored by the U.S. Department of Energy's (DOE's) office of Transportation Technologies, Energy Efficiency and Renewable Energy. Physically, it is a 64,500-ft(sup 2) building at the Oak Ridge National Laboratory (ORNL). The HTML houses six ''user centers,'' which are clusters of specialized equipment designed for specific types of properties measurements. The HTML was conceived and built in the mid-1980s in response to the oil embargoes of the 1970s. The concept was to build a facility that would allow direct work with American industry, academia, and government laboratories in providing advanced high-temperature materials such as structural ceramics for energy-efficient engines. The HTML's scope of work has since expanded to include other, non-high-temperature materials of interest to transportation and other industries

[en] Silicides of refractory metals have been employed in a wide variety of industrial applications ranging from electronics to aerospace technology. Silicide films are employed extensively in the electronics industry as contacts and interconnects in integrated silicon devices. Interest in silicides and silicide-based composites for high temperature applications has been renewed in recent years. MoSi₂ possesses many of the favorable properties that are required for a high temperature material. MoSi₂ has a high melting point, low density, excellent high temperature oxidation and corrosion resistance, and it exhibits metallic-like thermal and electrical conductivity. A few studies have been carried out on the growth of silicides in the Mo vs. Si system but have reported different results on layer growth kinetics. The objective of the present study was to investigate diffusion structures in Mo vs. Si solid-solid diffusion couples annealed at selected temperatures between 900--1,350 C and to explore the stoichiometry and texture of the MoSi₂ diffusion layer

[en] Accurate estimation of the radiation released at incidents, such as nuclear accidents or radiological terrorist events is of major importance for the prediction of health effects following such an incident. The luminescence properties of several materials are studied in order to assess their potential use as dosimeters in such cases. However, the protocols followed for such purposes are mainly those initially developed for dating. Multiple-aliquot protocols are mainly based on the Thermoluminescence response of the dosimeter used and require the availability of abundant material, while homogeneity of the luminescent substance in the entire sample is also a prerequisite in order to prepare similar aliquots. To account for the above drawbacks, several single-aliquot protocols have been suggested based on Optically Stimulated Luminescence (OSL), which however involve steps of heating the sample up to 300 °C, and as a result they can only be used for heat-resistant materials. In the present work, a novel single aliquot regenerative-dose protocol suitable for heat-sensitive materials exhibiting sensitization (called SARHS) for the estimation of the equivalent dose with OSL is proposed. The protocol eliminates any sensitization effects without encompassing any heating of the sample. Validation of the SARHS protocol was accomplished with three different heat-sensitive materials which exhibit sensitivity changes with the repeated use of the same sample (sensitization), i.e., dragonfly wings, a commercial solid drug (Daktarin) and chicken bones, in which the natural equivalent dose could be successfully recovered with negligible error even when fading, after exposure to irradiation, of the natural OSL signal was taken into account. - Highlights: • A new SAR protocol (SARHS) suitable for heat-sensitive materials is proposed. • SARHS protocol eliminates sensitization and no correction for it is needed. • SARHS was validated with 3 heat-sensitive materials exhibiting sensitization.

[en] We numerically investigate the effects of deformations on negative differential thermal resistance (NDTR) in single-walled carbon nanotubes (CNTs). It is found that various deformations have different effects on the regime of NDTR. The z -distortion of CNTs almost does not affect the regime of NDTR and the xy -distortion reduces the regime of NDTR. On increasing the bending angle and screw ratio, the NDTR regime reduces and eventually vanished. In addition, when the length of CNTs increases, the NDTR regime also reduces. Double NDTR even occur when the diameter of CNTs increases. These effects may be helpful in understanding the microscopic mechanism of NDTR and also would be conducive to further developments in designing and fabricating the thermal devices where NDTR plays an important role. (paper: classical statistical mechanics, equilibrium and non-equilibrium)

[en] The finite-time thermodynamic performance of a generalized Carnot-cycle, under the condition of mixed heat-resistances, is studied. The optimal configuration and the fundamental optimal relation between power and efficiency of the cycle are derived. The results provide some guidance for the design of practical engines

No abstract available