WorldWideScience

Sample records for heat-resistant alloy hastelloy

  1. Creep properties with short period excessive loadings on a nickel-base heat-resistant alloy Hastelloy XR

    International Nuclear Information System (INIS)

    A series of constant load and temperature creep tests and constant temperature creep tests with short period excessive loadings was carried out on a nickel-base heat-resistant alloy Hastelloy XR, which was developed for applications in the High-Temperature Engineering Test Reactor (HTTR), at temperatures ranging from 900 to 1000degC in order to examine the creep behaviors of the alloy under such conditions. The excessive loading levels were the design stress intensity values Sm for Hastelloy XR indicated in the HTTR high-temperature structural design code. Five to six time excessive loadings did not cause significant changes of the minimum creep rate or the time to onset of tertiary creep. About ten time excessive loadings did not cause significant changes of the time to rupture or the rupture elongation. The above-mentioned results suggest that the design stress intensity values Sm for Hastelloy XR have been determined reasonably. (author)

  2. Creep rupture properties of a nickel-base heat-resistant alloy Hastelloy XR under varying temperature/stress condition

    International Nuclear Information System (INIS)

    A series of constant temperature and load creep rupture tests and varying temperature and/or load creep rupture tests was carried out on a nickel-base heat-resistant alloy Hastelloy XR, which was developed for applications in the High-Temperature Engineering Test Reactor, at 850 to 1000degC in the simulated HTGR helium gas. This report describes the applicability of the conventional creep damage rules, i.e., the life fraction, the strain fraction and their mixed rules, to the alloy. The applicability was examined using the data under varying both temperature and load conditions as well as those, which were obtained in the previous work, under constant temperature and varying load conditions. The life fraction rule showed the best applicability of these three criteria. The good applicability of the rule was considered to show that the change of the chemical composition and/or the microstructure during exposure to the high-temperature simulated HTGR helium environment was not appreciable to affect the creep strength of Hastelloy XR. Though the life fraction rule under varying both temperature and load conditions is slightly less applicable than that under constant temperature and varying load conditions, it has been concluded that the rule is applicable in engineering design of high-temperature components made of Hastelloy XR. (author)

  3. Filler metal development for hastelloy alloy XR

    International Nuclear Information System (INIS)

    A method of alloy designing has been proposed and validated to develop the filler metal for Hastelloy alloy XR(nuclear reactor grade of Hastelloy alloy X), which is the candidate material for high temperature structure of High-Temperature Engineering Test Reactor (HTTR). In the filler metal development for Hastelloy alloy XR, materials of two heats were melted and fabricated with special emphasis placed on manufacturing process. One is the trial products (alloy termed 'C') designed by using multiple regression analysis in the range of the chemical composition specified as Hastelloy alloy X. The other is filler metal (alloy termed 'D') with optimum boron content in the same chemical composition as Hastelloy alloy XR. The results of the tests on several key items may be summarized as follows: (1) Weldments with alloy'C' showed higher strength and ductility at elevated temperatures than those of alloy'D'. (2) Weldments with alloy'D' had more excellent strength characteristics at elevated temperatures than those of the other conventional filler metals. (3) As for weldability, the crater cracks were slightly observed in the FISCO cracking test, but those were out of the problem in the degree of cracking from the viewpoint of practical application. The results of qualification tests on weldability showed good performance for all welding conditions of the present experiments. On the other hand, the mechanism of hot cracking initiation and the controlling factors in hot cracking susceptibility with relation to boron content have been clarified for Hastelloy alloy XR base metal. (author)

  4. Studies on neutron irradiation effects of iron alloys and nickel-base heat resistant alloys

    International Nuclear Information System (INIS)

    The present paper describes the results of neutron irradiation effects on iron alloys and nickel-base heat resistant alloys. As for the iron alloys, irradiation hardening and embrittlement were investigated using internal friction measurement, electron microscopy and tensile testings. The role of alloying elements was also investigated to understand the irradiation behavior of iron alloys. The essential factors affecting irradiation hardening and embrittlement were thus clarified. On the other hand, postirradiation tensile and creep properties were measured of Hastelloy X alloy. Irradiation behavior at elevated temperatures is discussed. (author)

  5. Alloying principles for tungsten heat resisting alloys

    International Nuclear Information System (INIS)

    The obtained experimental and literature data on the effect of alloyino. elements on structure, phase composition and properties of tungsten alloys are analysed on the base of which the main alloying principles of heat resistant ductile low-alloyed tuno.sten alloys are formulated. The methods of vacuum melting and powder metallurgy have been applied to prepare the alloys. Complex hardenino.: strain (epsilon > 95%), solid-solution (up to 2% Ta, up to 25-30 weight % molybdenum, rhenium) and precipitation (0.1-0.3 weoight % ZrC or HfC) is recommended for attaining the maximal short-term strength at 20-1500 deg C and long-term strength up to 1100 deg C

  6. Compatibility of heat resistant alloys with boron carbide, (2)

    International Nuclear Information System (INIS)

    In the present design of the control rod for the experimental Very High Temperature Gas-cooled Reactor, sintered pellets of boron carbide mixed with graphite are used as a neutron absorber, which are clad with the sheath material of Hastelloy XR. The sintered pellet contains 30 wt% of natural boron. Chemical reaction occurs between the neutron absorber and the sheath material when they contact mutually at elevated temperature. The term called compatibility is defined as the ability of those materials to be used together without undesirable reaction, in this report. The experimental results on the compatibility of both materials are presented and are discussed on three subjects as (1) the comparison between Hastelloy X and Hastelloy XR, (2) the long term exposure, (3) the effect of the reaction barrier. No difference was observed between Hastelloy X and Hastelloy XR within the conditions of the experiment at 8500C, 9500C and 10500C for each 100 h concerning the first subject. On the second, the penetration depth of 74 um and 156 um were observed on Hastelloy X reacted with sintered pellets (boron carbide and graphite) at 7500C for 3000 h and 8500C for 2000 h, respectively. On the third subject, Hastelloy X surfaces were coated with zirconia or alumina powder by plasma spraying process and by calorizing process in order to prevent the above mentioned reaction. These specimens were tested under two conditions: the one was a simple heat test of 10000C - 100 h and the other was five thermal cycles of 10000C - 20 h. The test results showed that no reaction occurred in the both alloys themselves and some of the coated layers were stripped or cracked. (author)

  7. Compatibility of heat resistant alloys with boron carbide

    International Nuclear Information System (INIS)

    The solid state compatibility of Hastelloy X and Incoloy 800 with boron carbide (B4C) were investigated at 850 - 10500C for periods of 20 - 2000 hrs for potential control rod application for Very High Temperature Gas-cooled Reactor (VHTR). These studies have shown both the alloys were incompatible with nearly stoichiometric B4C or B4C+C (70 wt% carbon) and they were less compatible with nearly stoichiometric B4C than with B4C over the temperature range 850 to 10000C. At 10500C for 100 hrs both of the alloys reacted with nearly stoichiometric B4C or B4C+C were melt by producing eutectic alloys. It was observed that boron and carbon penetration in the alloy is dominated by the grain boundary penetration. And some had a uniform reaction layer near the surface as a result of volume penetration. In general Incoloy 800 was more compatible than Hastelloy X and it was clearly seen by comparing the volume penetration depth reacted with nearly stoichiometric B4C at 9500C for 100 hrs. In Hastelloy X the depth was 225 ?m but in Incoloy 800 it was 117 ?m. The phases formed on alloys were identified to be Fe2B, Cr2B and Ni2B by X-ray diffraction. By the tensile test of reacted Hastelloy X material, it was found that the ultimate tensile strength was reduced due to the reaction of alloy with boron carbide but there was no change on the yield strength. (author)

  8. Study of creep and rupture behavior for a Ni-base heat resistant alloy improved for high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Creep-rupture tests of Hastelloy XR-II, a Ni-base heat resistant alloy modified for HTGR environment, were carried out in air and simulated HTGR helium at 700-1000degC up to 26,733 hours in the longest rupture time and about 207,000 hours in total testing times. The data was evaluated for high-temperature structural design using time-temperature parameter method. The boron content of Hastelloy XR-II (about 0.005 mass%) has been increased within the specification of Hastelloy XR. Experimental data and evaluated results were compared with the previous results for Hastelloy XR with low boron content (0.00028 mass%). Followings are a summary of the major findings. 1) Larger ductility is observed for Hastelloy XR-II than Hastelloy XR at higher temperatures. 2) The 100,000 h strength of Hastelloy XR-II is approximately twice of Hastelloy XR at 800 and 900degC. 3) The microstructural observation of creep-ruptured specimens showed a few macrocracks at 700degC, but round-type cavities at grain boundaries were pronounced with increasing temperatures. 4) With regard to the effect of the product forms, the creep-rupture strength of specimens sampled from tubes is slightly higher at 1000degC than that from plates. 5) The creep curves above 900degC were predominantly nonclassical. 6) The allowable stresses of So, Sm and St were computed using similar procedure employed for the previous data on Hastelloy XR with lower boron content. The significant increase in the So and St for Hastelloy XR-II over Hastelloy XR is recognized due to the improvement of both creep strength and creep-rupture ductility. (J.P.N.)

  9. New iron base heat resisting alloys for application in high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Heat resisting steels with relatively low nickel content have been designed and tested, which showed creep strength and corrosion resistance equivalent or superior to the present prime candidate nickel base alloys. The materials are expected to substitute nickel base alloys in the applications to the components in reactor core, e.g. neutron absorber sheathing, for which most nickel rich alloys are not suited because of their susceptibility to the loss of ductility caused by thermal neutron irradiation. 12Cr-12Ni-5Mo-5Cu-iron base alloys were designed and several similar versions were prepared. Tests at high temperatures were conducted on tensile properties at up to 10000C, creep rupture properties at 700 -- 9000C, toughness after aging at 700 and 8000C and corrosion resistance in the impure helium gas at 9000C. The helium environment was prepared simulating the impurity contents in the coolant of high temperature gas-cooled reactor. After exposure test to the impure helium, changes in weight and carbon content were measured, and metallurgical analysis was made by optical microscopy, EPMA analysis and X-ray diffraction. It was found that creep rupture strength of a heat of 12Cr-12Ni-5Mo-5Cu steel with small amounts of niobium was superior to the prime candidate material, Hastelloy alloy XR and was comparable to Inconel alloy 617, although some significant decrease in toughness occurred after aging at intermediate temperatures. Weight gain due to oxidation and carbon increase due to carburization of this steel in the simulated impure helium gas were lower than those of Hastelloy alloy XR. In conclusion this alloy, with appropriate modification, can be a potential substitutional material as the structural material to be used under thermal neutron exposure. The material may also be potential for general structural applications for high temperature gas-cooled reactors, substituting the commonly used material like Incoloy alloy 800H. (author)

  10. Modern cast heat resisting alloys for gas turbine blades

    International Nuclear Information System (INIS)

    The trends in heat resistant alloys designing are reviewed as applied to Ni-Co-Cr-W-Mo-Al-Nb system alloys. Manufacture of monocrystalline items is noted to be a promising way which assures high and stable mechanical properties. The alloys intended for monorystalline casting have to contain no elements (C, B, Zr) promoting grain boundary strengthening. The features of monocrystalline casting procedure and subsequent heat treatment are also considered

  11. Metal Dusting of Heat-Resistant Alloys

    OpenAIRE

    Al-meshari, Abdulaziz I.

    2008-01-01

    Metal dusting leads to disintegration of such alloys as iron and nickel-based into a “dust” of particulate metal, metal carbide, carbon, and/or oxide. It occurs in strongly carburising environments at 400-900°C. Literature survey has shown that alloys behave differently in metal dusting conditions based on their composition and the environment. Metal dusting mechanisms for iron and nickel-based alloys have been proposed but, nevertheless, have not been agreed upon and numerous modificati...

  12. Studies on the quality optimization of hastelloy alloy XR

    International Nuclear Information System (INIS)

    Interim results are reported on the multi-lateral joint research program on improving quality and its assurance basis of Hastelloy alloy XR with special emphasis placed on the effect of small amount of boron in the alloy. In the first phase work the exploratory examination on the optimum boron content was made. The results of the tests on several key items yield the optimum range of boron content as 40 to 70 ppm. The second phase work was organized to perform qualification tests on an industrial scale heat, which was specified its boron content (40 ppm) based on the previous phase work. The tests included weldability, tensile and creep-rupture properties, post aging toughness and corrosion and carburization resistance on different type of products. Tests are in progress, in which considerable difference in the degree of improvement was noted between plate and tube. (author)

  13. Evaluation of creep and relaxation data for hastelloy alloy x sheet

    International Nuclear Information System (INIS)

    Hastelloy alloy X has been a successful high-temperature structural material for more than two decades. Recently, Hastelloy alloy X sheet has been selected as a prime structural material for the proposed Brayton Isotope Power System (BIPS). The material also sees extensive application in the High-Temperature Gas-Cooled Reactor (HTGR). Design of these systems requires a detailed consideration of the high-temperature creep properties of this material. Therefore, available creep, creep-rupture, and relaxation data for Hastelloy alloy X were collected and analyzed to yield mathematical representations of the behavior for design use

  14. Electron microscopy study of eutectic type heat resisting alloy

    International Nuclear Information System (INIS)

    The method of diffraction electron microscopy has been applied to study the structure of a Ni-Cr heat resisting eutectic alloy after directed crystallization and creep tests under different modes. The alloy structure is presented as #betta#/#betta#'-matrix and long well faced NbC carbide crystals, ''Growth'' stacking faults of subtraction and introduction directed along the growth axis, appear in these crystals after crystallization. Subtraction stacking faults l6cated transverse to the crystal growth axis appear inside NbC crystals under creep. Interphase dislocations with orientation close to the edge one are disclosed on the #betta#/#betta#'-NbC interface

  15. Study of creep and rupture behavior for hastelloy alloy XR

    International Nuclear Information System (INIS)

    Creep tests of Hastelloy alloy XR (a modified Hastelloy alloy X developed for VHTR application) were carried out at 800, 900 and 10000C up to 310,000 hours in total testing times. The effects of environment (air and simulated VHTR helium), specimen diameters, product forms of the material (tube, plate and bar) and the neutron irradiation were also investigated. The ASME allowable stresses (Ssub(o), Ssub(m), and Ssub(t) in Code Case N-47) required to establish the design limit on the primary system were calculated using the current data. A procedure was developed to calculate equations which represented lower limits of the prediction intervals and the simultaneous tolerance intervals of strength on the basis of regression analysis. Statistical analysis of the three time-temperature parameter methods showed that the Manson-Succop method was better than that of either Larson-Miller or Orr-Sherby-Dorn in respect of curve fitting to the present creep-rupture data. Application of the Garofalo equation to the strain-time data resulted in a creep constitutive equation (tentative version) which represented the average isochronous stress-strain curves. It was recognized that there was little difference between air and helium in the creep-rupture strength up to about 10,000 hours. In helium environment there appeared slight indication that carburization occured in the early stage of exposure but no further carbon intrusion was observed in the steady state creep range. Comparison of creep behaviors among three product forms of the same heat indicated that the bar had superior creep-strength to the tube. This was attributed to the banded precipitation of carbides in the tube. As a result of significant ductility loss due to the neutron irradiation up to 8.7 x 1020n/cm2(th) at 600C, the rupture times reduced below about 20% that of the unirradiated one. (author)

  16. Influence of heating rate on corrosion behavior of Ni-base heat resistant alloys in simulated VHTR helium environment

    International Nuclear Information System (INIS)

    The influence of heating rate on corrosion and carbon transfer was studied for Ni-base heat resistant alloys exposed to simulated VHTR(very high temperature reactor) coolant environment. Special attention was focused to relationship between oxidation and carburization at early stage of exposure. Tests were conducted on two heats of Hastelloy XR with different boron(B) content and the developmental alloys, 113MA and KSN. Two kinds of heating rates, i.e. 80 0C/min and 2 0C/min, were employed. Corrosion tests were carried out at 900 0C up to 500 h in JAERI Type B helium, one of the simulated VHTR primary coolant specifications. Under higher heating rate, oxidation resistance of both heats of Hastelloy XR(2.8 ppmB and 40 ppmB) were equivalent and among the best, then KSN and 113MA followed in the order. Under lower heating rate only alloy, i.e. Hastelloy XR with 2.8 ppmB, showed some deteriorated oxidation resistance while all others being unaffected by the heating rate. On the other hand the carbon transfer behavior showed strong dependence on the heating rate. In case of higher heating rate, significant carburization occured at early stage of exposure and thereafter the progress of carburization was slow in all the alloys. On the other hand only slow carburization was the case throughout the exposure in case of lower heating rate. The carburization in VHTR helium environment was interpreted as to be affected by oxide film formation in the early stage of exposure. The carbon pick-up was largest in Hastelloy XR with 40 ppmB and it was followed by Hastelloy XR with 2.8 ppmB. 113MA and KSN were carburized only slightly. The observed difference of carbon pick-up among the alloys tested was interpreted to be attributed mainly to the difference of the carbon activity, the carbide precipitation characteristics among the alloys tested. (author)

  17. Nickel effect on heat resistance of Fe-20%Cr-14%Mn alloy

    International Nuclear Information System (INIS)

    Nickel effect on heat resistance and depth of a subscale layer in Fe-20% Cr-14% Mn alloy with preliminarily obtained surface ?-layer and without it is studied. Heat resistance has been determined throuqh an increase in sample mass after their oxidation at 1000 deg C during 100 h in the air. Nickel is stated to promote an essential increase of Fe-20% Cr-14% Mn alloy heat resistance only at the initial staqes of oxidation, i.e. before appearance of a subscale layer. After formation of subscale the alloy heat resistance depends on nickel content so much as nickel affects heat resistance of one-phase Fe-Cr-Ni ?-alloys. The subscale layer formed under high-temperature oxidation plays the role of protective coating. Oxidation of the investigated alloys is controlled by the rate of diffusion processes passinq through the subscale layer

  18. Etude expérimentale du soudage par laser YAG de l'alliage base nickel Hastelloy X Experimental study of YAG laser welding of nickel base alloy Hastelloy X

    Directory of Open Access Journals (Sweden)

    Graneix Jérémie

    2013-11-01

    Full Text Available Le procédé de soudage laser YAG est envisagé pour remplacer le procédé de soudage TIG manuel pour la réalisation de pièces de turboréacteur en alliage nickel-chrome-molybdène Hastelloy X. Cette étude expérimentale a permis de définir un domaine de soudabilité de cet alliage répondant aux critères spécifiques du secteur aéronautique. The YAG laser welding process is contemplated to replace the manual TIG welding process for the production of parts of turbojet in Hastelloy X. This experimental study has identified the field of weldability of this alloy to meet the specific requirements of the aerospace industry.

  19. Creep and tensile properties of alloy 800H-Hastelloy X weldments

    International Nuclear Information System (INIS)

    Hastelloy X and alloy 800H were joined satisfactorily by the gas tungsten arc welding process with ERNiCr-3 filler and the shielded metal arc welding process with Inco Weld A filler. Test specimens were of two types: (1) made entirely of deposited Inco Weld A and (2) machined transverse across the weldments to include Hastelloy X, filler metal (ERNiCr-3 or Inco Weld A), and alloy 800H. They were aged 2000 and 10,000 h and subjected to short-term tensile and creep tests. Inco Weld A and ERNiCr-3 are both suitable filler metals and result in welds that are stronger than the alloy 800H base metal

  20. Structure and properties of heat resisting coatings of Ni-Cr-Al-Y alloy

    International Nuclear Information System (INIS)

    Effect of long-range high-temperature annealings on the structure evolution and properties of heat resisting coatings of the nickel-chromium-aluminium-yttrium alloy used for protection from oxidation and corrosion of heat resisting alloys based on nickel was investigated. It is shown that the ultra-fine-dispersion coating structure provides in an initial state the microduplex structure formation with high ductility and stability at elevated temperatures. The coating exerts no influence on relative elongation and yield strength of the basic ZhS6U alloy at 2 mm sample thickness and more

  1. Putting into production of large-sized semiproducts of heat resistant nickel alloys

    International Nuclear Information System (INIS)

    he process of manufacturing large-sized semiproducts of heat resistant nickel base alloys (ZhS26, ZhS32, EhK79-ID, EhK151-ID, EhK152-ID) is described. The process runs according to the following production schedule: induction-vacuum (or open) melting ? electroslag remelting ? preliminary machining ? hot forging and pressing ? heat treatment. The tests include chemical express-analysis of the alloys obtained using a computerized optical emission spectrometer. Heat resistant nickel alloys are used for manufacture of turbine blades and discs for GTE

  2. Evaporation behavior of Hastelloy-X alloys in simulated very high temperature reactor environments

    International Nuclear Information System (INIS)

    A sequential analysis was made on the material degradations during exposure of nickel-base corrosionresistant austenitic alloys to simulated very high temperature reactor environments. The materials tested were two modified versions of Hastelloy-X in terms of both increased manganese content for improved compatibility and decreased manganese content for possible adverse effects. Quantitative analysis of the specimens after exposure for 1000 h at several temperature steps from 850 to 10500C have revealed the temperature-dependent aspects of the processes including the depletion of chromium and manganese due to oxidation, evaporation, and carbon transfer into and/or from the materials. The material with enriched manganese, developed and specified as Hastelloy-XR, showed enhanced resistance to loss of chromium in terms of both oxidation and evaporation

  3. Heat-resisting alloys for hard surfacing and sealing pad welding

    OpenAIRE

    R.O. Wielgosz

    2010-01-01

    The paper deals with heat-resisting alloys used to harden surfaces of elements operating in increased temperatures. It also deals with alloysused to seal cooperating surfaces of elements operating in the conditions of increased temperatures and aggressive utilities. Application methods and properties of thus obtained layers have been presented and adhesion of layers with matrix material has been assessed.

  4. KTA 625 alloy tube with excellent corrosion resistance and heat resistance

    International Nuclear Information System (INIS)

    The problems when seamless tubes are produced by using nickel base 625 alloy (61Ni-22Cr-9Mo-Cb) which is known as a corrosion resistant and heat resistant alloyF were examined, and the confirmation experiment was carried out on its corrosion resistance and heat resistance. Various difficulties have been experienced in the tube making owing to the characteristics due to the chemical composition, but they were able to be solved by the repeated experiments. As for the characteristics of the product, the corrosion resistance was excellent particularly in the environment containing high temperature, high concentration chloride, and also the heat resistance was excellent in the wide temperature range from normal temperature to 1000 deg C. From these facts, the wide fields of application are expected for these alloy tubes, including the evaporation and concentration equipment for radioactive wastes in atomic energy field. Expecting the increase of demand hereafter, Kobe Steel Ltd. examined the problems when seamless tubes are produced from the 625 alloy by Ugine Sejournet process. The aptitude for tube production such as the chemical composition, production process and the product characteristics, the corrosion resistance against chloride, hydrogen sulfide, polythionic and other acids,F the high temperature strength and oxidation resistance are reported. (Kako, I.)

  5. Structure of crater of sputtered electrode of heat resisting nickel alloy under granulation process

    International Nuclear Information System (INIS)

    Analysis of the structure formed in the crater of centrifigally sputtered electrode of Ni-Al-Ti-Cr-Co-W-Mo-Nb-Hf-B system granulated heat-resistant nickel alloy is carried out. Essential difference in behaviour of boron and carbon in crater near-the-surface layer is determined. This difference results from the depth of homogeneous distribution of boron (up to 1 mm) in contrast to that of carbon (up to 0.1mm). Up to 10 mm depth crack formation is detected. That crack formation results from the effect of thermal gradient at electrode sputtering followed by formation of submelting pores due to boron intensive migration to crack and along it on the surface of crater. Compositions of boride and carbide phases are determined, mechanisms of crater formation of electrode crater of heat-resistant granulated nickel alloy are suggested

  6. Relationship between carburization and zero-applied-stress creep dilation in Alloy 800H and Hastelloy X

    International Nuclear Information System (INIS)

    Typical HTGR candidate alloys can carburize when exposed to simulated service environments. The carbon concentration gradients so formed give rise to internal stresses which could cause dilation. Studies performed with Hastelloy X and Alloy 800H showed that dilations of up to almost 1% can occur at 10000C when carbon pickup is high. Dilation was normally observed only when the carbon increase was >1000 ?g/cm2 and ceased when diffusing carbon reached the center of the specimen. (Auth.)

  7. Elastic plastic fracture toughness values for a hastelloy alloy sample submitted to a static load

    International Nuclear Information System (INIS)

    In the High Temperature Reactor research programm of the french CEA, Hastelloy alloy plates contain mineral fibers used as insulating material and as such prevent the concrete core vessel from receiving excess heat. Due to the high pressure exerted on this insulating material, the Hastelloy plates are heavily stressed and, therefore, it is important to know their fracture strength. In the case of an elastic, brittle material, the fracture toughness is commonly defined through the well knownKsub(1c) parameter. But, for plastic materials, measuring Ksub(1c) requires very large samples and it was found more convenient to measure the fracture parameter Jsub(1c) instead of Ksub(1c). This parameter was determined according to the RICE or to the more sophisticated HERKLE and CORTEN formula. Two independent ways were followed to measure Jsub(1c): In the first one the shape of the crack after loading was made apparent by some fatigue cycles. After complete fracture of the sample, the amount of crack extension appears clearly and it becomes possible to generate a J resistance curve. As an alternative, we partially unloaded the specimen to get its compliance: the change in compliance was then supposed to coincide with the start of the crack extension. Finally a finite element code was used to compute the specimen state at the beginning of the crack extension. So we are able to obtain the shape of the Load-Displacement curve and to compare it with the experimental one. (orig.)e it with the experimental one. (orig.)

  8. Various problems in high temperature strength of heat resistant super-alloys for high temperature gas-cooled reactors

    International Nuclear Information System (INIS)

    In July, 1973, the research and development on the direct iron-making technology utilizing high temperature reducing gas were started as a big national project. As the research items, heat resistant super-alloys, high temperature heat exchangers, heat-insulating materials as well as high temperature gas-cooled reactors were enumerated. The aim of the research and development of heat resistant super-alloys is to develop the alloy which has the creep rupture strength for 50,000 hours of higher than 1 kg/mm2 in 1,000 deg C helium atmosphere. This alloy must be worked into tubes of 25 mm outside diameter, 5 mm thickness and at least 7 m length, and the secondary working and welding required for the manufacture of heat exchangers must be possible. The high temperature strength and workability of heat resistant alloys are incompatible properties. The creep rupture strength of heat resistant alloys deteriorates in helium atmosphere. In this paper, the test results on the high temperature strength of ten candiate alloys, which passed the manufacturing test and working test, are reported. The creep rupture strength of H-alloy and I-alloy in 1,000 deg C helium seemed to satisfy the condition. (Kako, I.)

  9. Influence of titanium: aluminum ratio in heat-resistant nickel alloys on their resistance to high-temperature salt corrosion

    International Nuclear Information System (INIS)

    This paper discusses how the ratio of titanium to aluminum in the range from zero to four with a total content of 2-8% influences the resistance of heat-resistant nickel-based alloys to sulfate and chloride melts. When the Ti/Al ratio lies between zero and one, there is marked weakening of sulfide corrosion, but this parameter has little influence on the resistance to chlorides. In order to obtain good mechanical properties and resistance to high-temperature corrosion, heat-resistant alloys should be alloyed with approximately equal amounts of titanium and aluminum

  10. Corrosion products and formation mechanism of hastelloy C-276 alloy in supercritical water at 600?

    International Nuclear Information System (INIS)

    The corrosion products of nickel-base alloy Hastelloy C-276 was investigated in supercritical water (SCW) at 600?/25 MPa through grazing incidence X-ray diffractometry, X-ray photoelectron spectroscopy and scanning electron microscopy, respectively. The results show that the uniform and complete oxide film was observed in SCW, which was identified to mainly consist of NiO, NiCr2O4, Cr2O3 and MoO2; The oxide films that had duplex structure were in poor in Ni and Mo, but the inner layer was rich in Cr. The loose outer layer lacked of protective, while the compact inner layer was favor of antioxidation. The formation mechanism of corrosion products on alloy C-276 in supercritical water seemed to be similar to that in high temperature water. The Ni(OH)2, NiO outer layer grew by dissolution and precipitation mechanism, while the Cr2O3 inner layer oxide was formed by oxygen diffusing inward and reacting with the retained Cr. (authors)

  11. Crevice Corrosion of Hastelloy C-276 and Inconel-625 Alloys in Chloride Environments, Determination of The Critical Crevice Solution

    International Nuclear Information System (INIS)

    The crevice corrosion of hastelloy C-276 and Inconel-625 alloys is investigated. The effect of temperature on both passive current and the critical pH (at which the passive film breaks down) is studied in detail. potentiodynamic studies have been used to determine the critical crevice solution (CCS) in terms of pH and chloride iron concentration, and passive current. The criteria of both Crolet and Old field and Sutton are used for the determination of the critical pH for crevice corrosion. The results show that the critical pH for crevice corrosion of Inconel-625 alloy as defined by Old field and Sutton seems to be a function of both temperature and chloride ion concentration, whereas the same relationship does not appear to hold between these variables and the critical pH when the Crolet criterion is applied. The critical pH of crevice solution for Inconel-625 may vary between 1.7 and 0.0 depending on environmental condition and criteria applied. However, for the case of hastelloy C-276 alloy the critical pH for crevice corrosion could not be detected when applying both criteria. The results indicate that hastelloy C-276 alloy is more resistant to crevice corrosion than Inconel-625 under the same experimental conditions. The experimental results passive current (Ipass) and de passivation pH (dpH) of this investigation could be utilized as inputs to a mathematical model employed for the prediction of incubation period required to reach the critical crevice solution cd to reach the critical crevice solution composition, which leads to permanent breakdown of passive film. 10 figs., 5 tabs

  12. The Effects of electron irradiation and fluoride salt melt ZrF4 - NaF on mechanical properties of hastelloy N type alloys

    International Nuclear Information System (INIS)

    NSC KIPT has cast Hastelloy T type alloys that are used in molten salt reactors (MSR). A study was made on the collective effects of exposure to electron irradiation and melt of sodium and zirconium fluorides at the temperature 650 degree C for 700 h on mechanical properties of these type alloys

  13. SEM, EDS, EPMA-WDS and EBSD characterization of carbides in HP type heat resistant alloys

    International Nuclear Information System (INIS)

    The microstructure of centrifugally cast heat resistant alloys of the HP-series (Fe-35Ni-25Cr-0.4C, wt.%) contains several minor phases, like carbides (M7C3, M23C6 and MC). Several alloys are characterized by means of scanning electron microscopy in back-scattered electron imaging and energy dispersive spectroscopy, of electron probe micro-analysis by X-ray wavelength dispersive spectroscopy, and of electron back-scattered diffraction. On the one hand, scanning electron microscopy imaging in the back-scattered mode, associated with energy dispersive spectroscopy analysis and electron back-scattered diffraction, can lead to the identification of all phases, but with a lack of accuracy in certain cases. On the other hand, electron probe micro-analysis by X-ray wavelength dispersive spectroscopy alone can always provide a strict identification of all phases, with additional precise information on phase composition, including for light elements, which is important in the case of carbides

  14. Creep behavior for Hastelloy-XR

    International Nuclear Information System (INIS)

    Creep-rupture tests for Hastelloy-XR, a Ni-base heat resistent alloy, were conducted in air at the temperature of 650 to 900 deg C. Times to rupture ranged from 1000 to 16000 h. As results of tests, creep curves were observed to vary depending on both temperature and stress, particularly on temperature. Namely, they showed typical classical shapes consisting of primary, secondary and tertiary creep at 650 to 700 deg C. The regions of primary and secondary creep decreased gradually as the temperature became higher and in one case of 900 deg C and high stress, only tertiary creep was observed. Metallurgical observation by optical microscope showed the similar inclination. Some differences were found concerning rupture morphology and void shape between temperatures below 750 deg C and above 850 deg C. (author)

  15. Aging of a cast 35Cr–45Ni heat resistant alloy

    International Nuclear Information System (INIS)

    Highlights: ? The as-cast microstructure is made of an austenitic matrix and primary carbides. ? The carbides are of two different types: Cr- and Nb-rich. ? The microstructure changes during aging. ? These microstructural changes result in the degradation of mechanical properties. - Abstract: The microstructural evolution during aging and its effect on the mechanical properties of a centrifugally cast 35Cr–45Ni heat resistant alloy was studied by means of optical and electron microscopy, and by mechanical testing in samples aged in air at 750 °C for a period of time of up to 1000 h. The as-cast microstructure consisted of an austenitic matrix and a network of two types of primary carbides that were identified as NbC and M7C3 by their light and dark tones when viewed in backscattered electron mode in a scanning electron microscope. Aging promoted the occurrence of different phenomena such as the transformation of primary M7C3 to M23C6 carbides, precipitation of secondary M23C6 carbides and the transformation of NbC to Nb3Ni2Si. It was found that aging promoted an increase in Vickers microhardness of more than 50%, the increment in tensile strength of around 20% and the reduction in ductility of close to 70%.

  16. Effect of alloying on precipitation of intermetallic phases in heat-resistant titanium alloys

    Science.gov (United States)

    Popov, A. A.; Leder, M. O.; Popova, M. A.; Rossina, N. G.; Narygina, I. V.

    2015-03-01

    The effect of alloying elements, the contents of which were varied within an alloy grade, on the precipitation processes of third phases has been studied. Species of precipitated silicide particles and their effect on the precipitation of the ?2 phase are considered. It was shown that, during aging, the precipitation of (Ti,Zr)5Si3( S 1) silicide particles takes place, which, during holding, are enriched in zirconium atoms and transform into (Ti,Zr)6Si3 ( S 2) and (Zr,Ti)2Si ( S 3) silicides.

  17. Experimental evaluation of the characteristics of super-heat-resisting Nb-based and Mo-based alloys

    International Nuclear Information System (INIS)

    Both the Nb-based and Mo-based alloys have been designed and developed in order to establish the frontier technique for super-heat-resisting materials used in the liquid alkali metal environment at high temperatures. In this study, mechanical properties of the designed Nb-1Hf alloy were experimentally evaluated. In addition, the brittleness of Nb-based alloys observed at 1073K were discussed. Moreover, characteristics of both the designed Nb-based and the Mo-based alloys were summarized in a consistent way. The tensile strength of the designed Nb-1Hf alloy was slightly lower at room temperature than that of the commercial Nb-1Zr alloy. But, the designed alloy was superior in high temperature creep properties to any other solid solution hardened Nb-based alloys. In addition, the modulated structure was observed in the brittle specimen crept at 1073K, but not in the ductile specimen crept at 1273K. Therefore, it caused probably the brittleness of the Nb-1Zr alloy at 1073K. It was concluded that all the designed Nb-1Hf, Mo-15Re-0.1Zr and Mo-15Re-0.1Zr-0.1Ti alloys had an excellent total balance in the tensile and creep properties at high temperatures, corrosion resistance to liquid Li and cold-workability, compared to other experimental and commercial alloys. (J.P.N.)

  18. Aging of a cast 35Cr-45Ni heat resistant alloy

    Energy Technology Data Exchange (ETDEWEB)

    Sustaita-Torres, Ireri A., E-mail: ireri.sustaita@gmail.com [Unidad Academica de Ingenieria, Universidad Autonoma de Zacatecas, 98000 Zacatecas (Mexico); Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, 66450 San Nicolas de los Garza (Mexico); Haro-Rodriguez, Sergio, E-mail: haros907@hotmail.com [Unidad Academica de Ingenieria, Universidad Autonoma de Zacatecas, 98000 Zacatecas (Mexico); Guerrero-Mata, Martha P., E-mail: martha.guerreromt@uanl.edu.mx [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, 66450 San Nicolas de los Garza (Mexico); Garza, Maribel de la, E-mail: maribeldelagarza@yahoo.com.mx [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, 66450 San Nicolas de los Garza (Mexico); Valdes, Eduardo, E-mail: eduardo.valdes.57@gmail.com [Instituto Tecnologico de Saltillo, 25280 Saltillo (Mexico); Deschaux-Beaume, Frederic, E-mail: deschaux@iut-nimes.fr [Mechanical and Civil Engineering Laboratories, Universite de Montpellier 2, IUT Nimes, 30907 Nimes (France); and others

    2012-04-16

    Highlights: Black-Right-Pointing-Pointer The as-cast microstructure is made of an austenitic matrix and primary carbides. Black-Right-Pointing-Pointer The carbides are of two different types: Cr- and Nb-rich. Black-Right-Pointing-Pointer The microstructure changes during aging. Black-Right-Pointing-Pointer These microstructural changes result in the degradation of mechanical properties. - Abstract: The microstructural evolution during aging and its effect on the mechanical properties of a centrifugally cast 35Cr-45Ni heat resistant alloy was studied by means of optical and electron microscopy, and by mechanical testing in samples aged in air at 750 Degree-Sign C for a period of time of up to 1000 h. The as-cast microstructure consisted of an austenitic matrix and a network of two types of primary carbides that were identified as NbC and M{sub 7}C{sub 3} by their light and dark tones when viewed in backscattered electron mode in a scanning electron microscope. Aging promoted the occurrence of different phenomena such as the transformation of primary M{sub 7}C{sub 3} to M{sub 23}C{sub 6} carbides, precipitation of secondary M{sub 23}C{sub 6} carbides and the transformation of NbC to Nb{sub 3}Ni{sub 2}Si. It was found that aging promoted an increase in Vickers microhardness of more than 50%, the increment in tensile strength of around 20% and the reduction in ductility of close to 70%.

  19. Variation of microstructures and mechanical properties of hot heading process of super heat resisting alloy Inconel 718

    International Nuclear Information System (INIS)

    Metal forming is the process changing shapes and mechanical properties of the workpiece without initial material reduction through plastic deformation. Above all, because of hot working carried out above recrystallization temperature can be generated large deformation with one blow, it can produce with forging complicated parts or heat resisting super alloy such as Inconel 718 has the worst forgeability. In this paper, we established optimal variation of hot heading process of the Inconel 718 used in heat resisting component and evaluated mechanical properties hot worked product. Die material is SKD61 and initial temperature is 300 .deg. C. Initial billet temperature and punch velocity changed, relatively. Friction coefficient is 0.3 as lubricated condition of hot working. CAE is carried out using DEFORM software before marking the tryout part, and it is manufactured 150 ton screw press with optimal condition. It is know that forming load was decreased according to decreasing punch velocity

  20. Evaluation on materials performance of hastelloy alloy XR for HTTR uses. 4. Tensile properties of base metals and welded joints

    International Nuclear Information System (INIS)

    Tensile properties due to thermal aging on Hastelloy Alloy XR base metals and welded joints were investigated as a series of evaluation test on the base metals and filler metals for the High Temperature Engineering Test Reactor (HTTR) components. Tensile test in air was performed at R.T. and then same temperatures as the thermal aging temperatures after the specimens were aged at 800, 900 and 1000degC for 1000hrs. In comparison with the previous data, the present results had no significant difference on the strength characteristics, and were in the previous data band on the ductility. Therefore, it is concluded that these base metals and filler metals for the HTTR components have excellent tensile properties. (author)

  1. Influence of the brazing parameters on microstructure and mechanical properties of brazed joints of Hastelloy B2 nickel base alloy

    International Nuclear Information System (INIS)

    A study of the high vacuum brazing process of solid solution strengthened Hastelloy B2 nickel alloy has been done. A first stage of research has focused on the selection of the most appropriate brazing filler metal to the base material and vacuum furnace brazing process. The influence of welding parameters on joint microstructure constituents, relating the microstructure of the joint to its mechanical properties, has been evaluated. Two gaps of 50 and 200 micrometers, and two dwell times at brazing temperature of 10 and 90 minutes were studied. The braze joint mainly consists of the nickel rich matrix, nickel silicide and ternary compounds. Finally, the results of this study have shown the high bond strength for small gaps and increased dwell times of 90 minutes. (Author)

  2. Electrochemical investigation of the effect of different laser surface treatments on Hastelloy G alloy

    International Nuclear Information System (INIS)

    In the present study, the corrosion resistance behavior of untreated and laser treated Hastelloy was examined. The electrochemical tests including potentiodynamic polarization, Tafel analysis, and linear polarization resistance were carried out in deaerated 0.5% NaCl aqueous solution at room temperature. Surface roughness was measured to correlate it with corrosion resistance properties of the materials. Surface morphology of the samples after corrosion tests was examined using scanning electron microscopy and energy dispersive X-ray spectroscopy. Results showed that laser treated surface exhibited better corrosion resistance properties as compared to untreated surface. (orig.)

  3. Hardening mechanisms in a dynamic strain aging alloy, Hastelloy X, during isothermal and thermomechanical cyclic deformation

    Science.gov (United States)

    Miner, R. V.; Castelli, M. G.

    1992-01-01

    The relative contributions of the hardening mechanisms in Hastelloy X during cyclic deformation were investigated by conducting isothermal cyclic deformation tests within a total strain range of +/-0.3 pct and at several temperatures and strain rates, and thermomechanical tests within several different temperature limits. The results of the TEM examinations and special constant structure tests showed that the precipitation on dislocations of Cr23C6 contributed to hardening, but only after sufficient time above 500 C. Solute drag alone produced very considerable cyclic hardening. Heat dislocation densities, peaking around 10 exp 11 per sq cm, were found to develop at temperatures producing the greatest cyclic hardening.

  4. Helium dilution effect on hydrogen permeation in 316L stainless steel and nickel-base heat-resistant alloys

    Science.gov (United States)

    Kishimoto, N.; Tanabe, T.; Suzuki, T.; Yoshida, H.

    1985-01-01

    Effects of inert-gas dilution on hydrogen permeation have been investigated in 316L stainless steel, Inconel 600, Inconel 750, Nimonic 80A and Hastelloy X at 1173 K and 1073 K, by employing a gas-flow system. We used gas mixtures of hydrogen and helium, whose hydrogen concentration ranged from 10 -5 to 10 -1. For the steady-state permeation, the dilution of hydrogen caused no anomalous effects and the permeation rate conformed to Sieverts' law. However, for the transient state, the hydrogen permeation was retarded by the dilution with helium. The retardation effect is discussed in terms of an adsorption model and explained by a decrease in sticking probability at the alloy surface with the dissociative adsorption of hydrogen.

  5. Helium dilution effect on hydrogen permeation in 316L stainless steel and nickel-base heat-resistant alloys

    International Nuclear Information System (INIS)

    Effects of inert-gas dilution on hydrogen permeation have been investigated in 316L stainless steel, Inconel 600, Inconel 750, Nimonic 80A and Hastelloy X at 1173 K and 1073 K, by employing a gas-flow system. We used gas mixtures of hydrogen and helium, whose hydrogen concentration ranged from 10-5 to 10-1. For the steady-state permeation, the dilution of hydrogen caused no anomalous effects and the permeation rate conformed to Sieverts' law. However, for the transient state, the hydrogen permeation was retarded by the dilution with helium. The retardation effect is discussed in terms of an adsorption model and explained by a decrease in sticking probability at the alloy surface with the dissociative adsorption of hydrogen. (orig.)

  6. Development of heat resistant Pb-free joints by TLPS process of Ag and Sn-Bi-Ag alloy powders

    Directory of Open Access Journals (Sweden)

    Ohnuma I.

    2012-01-01

    Full Text Available TLPS (Transient Liquid Phase Sintering process is a candidate method of heat-resistant bonding, which makes use of the reaction between low-melting temperature powder of Sn-Bi base alloys and reactive powder of Ag. During heat treatment above the melting temperature of a Sn-Bi base alloy, the molten Sn-Bi reacts rapidly with solid Ag particles, which results in the formation of heat-resistant intermetallic compound (IMC. In this study, the TLPS properties between Sn-17Bi-1Ag (at.% powder with its liquidus temperature of 200°C and pure Ag powder were investigated. During differential scanning calorimetry (DSC measurement, an exothermic reaction and an endothermic reaction occurred, which correspond to the formation of the e-Ag3Sn IMC phase and the melting of the Sn-17Bi-1Ag alloy, respectively. After the overall measurement, the obtained reactant consists of the Ag3Sn-IMC and Bi-rich phases, both of which start melting above 250°C, with a small amount of the residual Sn-Bi eutectic phase. These results suggest that the TLPS process can be applied for Pb-free heatresistant bonding.

  7. X-ray fluorescence analysis of nickel-based heat-resisting alloys by matrix correction using theoretical alpha coefficients

    International Nuclear Information System (INIS)

    The study of the X-ray fluorescence analysis of main component and alloying elements in nickel-based heat-resisting alloys has been performed. The calibration curves were made by using NBS SRM's, JAERI and home-made nickel-based standard samples and the correction was made for the matrix effects using theoretical alpha coefficients. Accuracies (?d) for respective element obtained from those curves with correction were improved, especially for chromium and iron, in comparison with uncorrected ones. The relative standard deviation for each element was in the ragne of 0.25 ? 1.27 % with the exception of aluminum (0.26 Al%; r.s.d. 3.01 %). The analytical ranges were as follows; Cr(12.75 ? 26.49 %), Mo(1.09 ? 9.18 %), W(0.019 ? 4.57 %), Co(0.39 ? 8.90 %), Ti(0.35 ? 3.44 %), Al(0.15 ? 6.68 %), Nb(0.88 ? 5.38 %), Fe(0.12 ? 23.2 %), Mn(0.01 ? 0.65 %). The analytical values of nickel-based heat-resisting alloys such as Inconel 713LC, Mar-M247 and so on, showed good agreement with those determined by chemical analysis. (author)

  8. Low-cycle fatigue of Type 347 stainless steel and Hastelloy alloy X in hydrogen gas and in air at elevated temperatures

    Science.gov (United States)

    Jaske, C. E.; Rice, R. C.; Buchheit, R. D.; Roach, D. B.; Porfilio, T. L.

    1976-01-01

    An investigation was conducted to assess the low-cycle fatigue resistance of two alloys, Type 347 stainless steel and Hastelloy Alloy X, that were under consideration for use in nuclear-powered rocket vehicles. Constant-amplitude, strain-controlled fatigue tests were conducted under compressive strain cycling at a constant strain rate of 0.001/sec and at total axial strain ranges of 1.5, 3.0, and 5.0 %, in both laboratory-air and low-pressure hydrogen-gas environments at temperatures from 538 to 871 C. Specimens were obtained from three heats of Type 347 stainless steel bar and two heats of Hastelloy Alloy X. The tensile properties of each heat were determined at 21, 538, 649, and 760 C. The continuous cycling fatigue resistance was determined for each heat at temperatures of 538, 760, and 871 C. The Type 347 stainless steel exhibited equal or superior fatigue resistance to the Hastelloy Alloy X at all conditions of this study.

  9. Evaluation on materials performance of Hastelloy Alloy XR for HTTR uses-5 (Creep properties of base metal and weldment in air)

    International Nuclear Information System (INIS)

    Creep properties of weldment made from Hastelloy Alloy XR base metals and filler metals for the High Temperature Engineering Test Reactor (HTTR) components were examined by means of creep and creep rupture tests at 900 and 950degC in air. The results obtained are as follows: creep rupture strength was nearly equal or higher than that of Hastelloy Alloy XR master curve and was much higher than design creep rupture strength [SR]. Furthermore, creep rupture strength and ductility of the present filler metal was in the data band in comparison with those of the previous filler metals. It is concluded from these reasons that this filler metal has fully favorable properties for HTTR uses. (author)

  10. High temperature corrosion of heat-resisting alloys by borosilicate melts containing simulated high level nuclear wastes

    International Nuclear Information System (INIS)

    In connection with the development of vitrified solidification process of high level liquid wastes (HLLW) by metallic vessel, the high temperature corrosion of some heat-resisting alloys, such as stainless steel, Incoloy and Inconel, were investigated with the molten borosilicate glass containing simulated HLLW in the temperature range of 1,000--1,2000C for 3--50 days. The concentration distributions of various constituents in the vicinity of the interface between the glass and the various metals were determined by means of EPMA. In the case of stainless steel, the general corrosion of alloys was observed without a protective layer. But in the case of both of Incoloy and Inconel, a chromium oxide layer was consequently formed between the glass and the metal, giving a protective film against general corrosion of alloys. When a MgCr2O4 layer on the chromium oxide layer and the alumina in alloy were, furthermore, formed, the corrosion of alloys became extremely depressed. The growth rate of the layer was controlled by chromium diffusion in alloy. The values of the effective diffusion coefficients D tilde sub(Cr) were approximately 1x10-10cm2/s at 1,1050C. (author)

  11. Effect of yttrium on the oxide scale adherence of pre-oxidized silicon-containing heat-resistant alloy

    International Nuclear Information System (INIS)

    Highlights: ? AE experiment shows yttrium has a beneficial effect on the pre-oxidized HP40 alloy. ? Yttrium facilitates the formation of internal oxide after 10 h of oxidation. ? Internal oxide changes the rupture behaviour of the oxide scale. ? Twins form in the internal oxide and improve the binding strength of the scale. - Abstract: This paper investigates the effect of the rare earth element yttrium on the rupture behaviour of the oxide scale on the silicon-containing heat-resistant alloy during cooling. After 10 h of oxidation, yttrium is found to facilitate the formation of internal oxides (silica) at the scale-matrix interface. Due to the twinning observed by scanning transmission electron microscopy (STEM) in silica, the critical strain value for the scale failure can be dramatically improved, and the formation of cracks at the scale-matrix interface is inhibited.

  12. High-temperature low-cycle fatigue and tensile properties of Hastelloy X and alloy 617 in air and HTGR-helium

    International Nuclear Information System (INIS)

    Results of strain controlled fatigue and tensile tests are presented for two nickel base solution hardened alloys which are reference structural alloys for use in several high temperature gas cooled reactor concepts. These alloys, Hastelloy X Inconel 617, were tested at temperatures ranging from room temperature to 8710C in air and impure helium. Materials were tested in the solution annealed as well as in the pre-aged condition where aging consisted of isothermal exposure at one of several temperatures for periods of up to 20,000 h. Comparisons are also given between the strain controlled fatigue lives of these alloys and several other commonly used alloys all tested at 5380C

  13. High temperature strength of hastelloy XR electron beam weld metal

    International Nuclear Information System (INIS)

    As for the electron beam welded joints of Hastelloy XR, which is the heat resistant alloy for high temperature gas-cooled reactors, the tensile, creep rupture and low cycle fatigue characteristics at high temperature of the weld metal were determined, and compared with the parent material. As the result, it was found that the strength of the welded joint can be treated as nearly the same as that of the parent metal up to 900 deg C, while at 1000 deg C, the tensile strength and creep rupture strength become lower than those of the parent material, therefore the enough strength-design consideration is indispensable for the application at 1000 deg C. (Kako, I.)

  14. Selection of canister materials: electrochemical corrosion tests of HASTELLOY C4 and other Ni-Cr(-Mo) alloys in chloride containing solutions

    International Nuclear Information System (INIS)

    Several Ni-Cr(-Mo) alloys (HASTELLOY C4, INCONEL 625, SANICRO 28, INCOLOY 825, INCONEL 690) were tested by electrochemical methods to characterize their corrosion behaviour in chloride containing solutions at various temperatures and pH-values in respect to their application as canister materials for final radioactive waste storage. Especially, HASTELLOY C4 which proved to have the highest corrosion resistance of all tested alloys was tested by the following electrochemical methods: (1) Poteniodynamic measurements to determine the characteristic potentials, passive current densities and critical pitting potentials. (2) Potentiostatic measurements in order to evaluate the duration of the incubation period at various potentials. (3) Galvanostatic measurements in order to characterize critical pitting potentials. As electrolyte 1 m H2SO4 was used, as parameters temperature, chloride content and pH-value were varied. Variation of temperature gives the following results: an increase in temperature leads to an increase of the critical passivation current density, the passive potential bandwidth decreases slightly and the passive current density increases with rising temperature. The addition of different chloride contents to the H2SO4 solution shows the following effects: the critical passivation current density and the passive current density increase with increasing chloride concentration and both, the critical pitting potentialn and both, the critical pitting potentials and the pitting nucleation potentials, shift towards negative values. As third parameter the pH-value was varied. As expected, an increase of the pH-value extends the passive region to more negative values, the passive current density decreases. The variation of the pH-value does not affect the critical pitting potential. All tested alloys showed a clearly limited resistance against pitting corrosion phenomena. However, the best corrosion behaviour is shown by HASTELLOY C4, which has of all tested alloys the lowest passivation current density and the largest potential region with protection against local corrosion phenomena. (author)

  15. Phase transformations in heat resisting nickel alloy ZhS6U after fatigue testing

    Energy Technology Data Exchange (ETDEWEB)

    Kishkin, S.T.; Morozova, G.I.; Belyaev, M.S.; Gnevsheva, A.I.; Sorokina, L.P.

    1984-12-01

    The phase transformations and alloying element distribution between the phases in the ZhS6U alloy weakened in the process of fatigue testing are investigated. It is shown by the methods of physico-chemical phase analysis and electron microscopy that stresses acting at working temperatures contribute to the coagulation of ..gamma..'-phase, raise its chemical heterogeneity and contribute to the decay into ..gamma../sub 1/ and ..gamma../sub 2/ fractions, the latter differing in their composition and structural stability. The ..gamma../sub 1/ to ..gamma../sub 2/ fraction relationship directly depends on high-temperature testing duration and alloy strength level.

  16. Study on thermal treatment regime effect on the phase content of heat resisting alloys

    International Nuclear Information System (INIS)

    The changes are studied in nickel-chrome alloys on heat treatment and ageing by using the method of electrochemical phase separation with measurement of the amount of segregated ?-phase and its parameter Eh1437BUVD, EhI1698VD and ZhS6-KP alloys were used for the study. The amount of ?-phase in nickel-chrome-based alloys changes in the course of ageing only in the initial period up to 4 hr. The cooling rate on hardening affects the amount of ?-phase, i.e. the higher the rate, the lower is the content of ?-phase. An increase in the time of holding at the hardening temperature increases the amount of strengthening phase

  17. Tungsten determination in heat resistant nickel-base-alloys by the method of atomic absorption

    International Nuclear Information System (INIS)

    A method of atomic absorption was developed. It allows for the tungsten to be determined in heatresistant nickel-base-alloys within the range 0.01 to 7%. It consists in precipitating tungsten acid in the presence of alkaloids with its following decomposition by hydrofluoric acid in the teflon bomb. (author)

  18. Evaluation on materials performance of Hastelloy Alloy XR for the High Temperature Engineering Test reactor components. Weldability and high temperature strength properties

    International Nuclear Information System (INIS)

    Weldability and high temperature strength properties of Hastelloy Alloy XR were investigated in order to evaluate the materials performance of base metal and filler metal for the High Temperature Engineering Test Reactor (HTTR) uses. The weldability was examined by means of the chemical analysis in the deposited metals, optical microscopy, FISCO test, hardness measurements and bend test. The high temperature strength properties were investigated through tensile tests at R.T., 800, 900 and 950degC in air, and creep and creep rupture tests at 900 and 950degC in air. The results obtained by each test showed favorable performance. In particular, the bend test which is considered to be critical pass demonstrated low susceptibility to weld cracking through the optimization of B and C contents in the filler metal and by narrowing the groove. Creep rupture strength was nearly equal or higher than those of Hastelloy Alloy XR master curve and was much higher than design creep rupture strength [SR]. Therefore, it is concluded that weldability, tensile and creep properties with these base metals and filler metals for the HTTR components are entirely satisfactory. (author)

  19. Investigation into effect of chemical composition changes of nickel powder heat resisting alloy on the temperature of absolute dissolution of ?' phase

    International Nuclear Information System (INIS)

    The effect of the chemical composition changes of nickel powder alloy on the temperature of absolute dissolution of ?' phase is studied. Ten melts of nickel powder heat resisting alloy of the Ni-Cr-Co-Al-Ti-W-Mo-Nb system have been taken as the material of investigation. Temperatures of absolute dissolution of the above alloy, differed in the content of alloyed components within the limits of the grade composition, are determined with the use of metallographical and resistant-metrical analyses. Using the method of ''accidental balance'' established is a dependence between changes (within the limits of the grade composition of the alloy) in the content of alloyed components and the temperature of absolute dissolution of ?' phase

  20. Resistance of heat resisting steels and alloys to thermal and mechanical low-cycle fatigue

    International Nuclear Information System (INIS)

    Carried out is a comparative evalUation of resistance of different materials to thermocyclic deformation and fracture on the base of the experimental data on thermal and mechanical low-cycle fatigUe. Considered are peculiarities of thermal fatigue resistance depending on strength and ductility of the material. It is shown, that in the range of the cycle small numbers before the fracture preference is given to the high-ductility cyclically strengthening austenitic steels of 18Cr-10Ni type with slight relation of yield strength to the ?sub(0.2)/?sub(B) tensile strength Highly alloyed strength chromium-nickel steels, as well as cyclically destrengthening perlitic and ferritic steels with stronger ?sub(0.2)/?sub(B) relation as compared with simple austenitic steels turn to be more long-lived in the range of the cycle great numbers berore fracture. Perlitic steels are stated to have the lowest parameter values of the K crack growth intensity under the similar limiting conditions of the experiment, while steels and alloys with austenite structure-higher values of the K parameter

  1. Influence of crystallization parameters on perfection of single crystals of heat resistant nickel alloy

    International Nuclear Information System (INIS)

    A consideration is given to the dependence of structure morphology and variable section monocrystals of nickel base alloy, mass.% the degree of perfection of cylindrical and (Ni-9.9Co-8.4W-5.5Al-4.7Ta-4.0Cr-3.3Re-1.2Nb-0.5Mo-0.15C) on crystallization rates (5, 10, 30, 40, 50 mm x min-1) and crystallographic orientation of a crystal-melt interface. Crystallization parameters which provide formation of disperse dendritic structure with low amount of crystal defects along the whole length of monocrystalline castings have been determined. Experimental and calculated values are compared for the first order dendritic parameter depending on growth rate at a given temperature gradient at crystallization front. 9 refs., 5 figs., 3 tabs

  2. Creep rupture properties under varying load/temperature conditions on a nickel-base heat-resistant alloy strengthened by boron addition

    International Nuclear Information System (INIS)

    A series of constant load and temperature creep rupture tests and varying load and temperature creep rupture tests was carried out on Hastelloy XR whose boron content level is 60 mass ppm at 900 and 1000degC in order to examine the behavior of the alloy under varying load and temperature conditions. The life fraction rule completely fails in the prediction of the creep rupture life under varying load and temperature conditions though the rule shows good applicability for Hastelloy XR whose boron content level is below 10 mass ppm. The modified life fraction rule has been proposed based on the dependence of the creep rupture strength on the born content level of the alloy. The modified rule successfully predicts the creep rupture life under the test conditions from 1000degC to 900degC. The trend observed in the tests from 900degC to 1000degC can be qualitatively explained by the mechanism that the oxide film which is formed during the prior exposure to 900degC plays the role of the protective barrier against the boron dissipation into the environment. (author)

  3. Development of Simultaneous Corrosion Barrier and Optimized Microstructure in FeCrAl Heat-Resistant Alloy for Energy Applications. Part 1: The Protective Scale

    Science.gov (United States)

    Pimentel, G.; Aranda, M. M.; Chao, J.; González-Carrasco, J. L.; Capdevila, C.

    2015-05-01

    Coarse-grained Fe-based oxide dispersion-strengthened (ODS) steels are a class of advanced materials for combined cycle gas turbine systems to deal with operating temperatures and pressures of around 1100°C and 15-30 bar in aggressive environments, which would increase biomass energy conversion efficiencies up to 45% and above. This two-part paper reports the possibility of the development of simultaneous corrosion barrier and optimized microstructure in a FeCrAl heat-resistant alloy for energy applications. The first part reports the mechanism of generating a dense, self-healing ?-alumina layer by thermal oxidation, during a heat treatment that leads to a coarse-grained microstructure with a potential value for high-temperature creep resistance in a FeCrAl ODS ferritic alloy, which will be described in more detail in the second part.

  4. Control method of purification system of helium coolant for suppressing decarburization of heat-resistant alloy used in very high temperature gas cooling reactors

    International Nuclear Information System (INIS)

    It is important to control the chemistry of the helium coolant used in high-temperature gas-cooled reactors (HTGRs). The effect of a decarburizing environment on the creep rupture properties tends to decrease the creep rupture life of the heat-resistant alloy used in heat exchangers. In this paper, we describe an active control method for the concentration of impurities using the existing helium purification system, which consists of a helium heater, a copper oxide trap (CuOT), a molecular sieve trap, a cold charcoal trap, and a bypass line. Analysis showed that the efficiency control of CuOT is effective in improving the decarburizing atmosphere. The efficiency control of CuOT increases the concentrations of carbon monoxide and hydrogen. It was found that both the enrichment of carbon monoxide suggested in previous studies and the enrichment of hydrogen are also effective in forming the carburizing atmosphere. (author)

  5. Degradation and recovery of the {gamma}{sup {prime}}-phase in heat-resistant nickel alloys

    Energy Technology Data Exchange (ETDEWEB)

    Morozova, G.I.; Sorokina, L.P.; Bogina, N. Kh. [All-Russian Inst. of Aircraft Materials, Moscow (Russian Federation)

    1995-09-01

    High-alloy nickel alloys are the principal structural material for parts of hot channels of gas turbine engines (GTE), which withstands high temperatures and loads and has a long service life. The high high-temperature strength is a result of complex alloying and phase composition that ensures the stability of the alloy structure in a field of high-temperatures and stresses. The {gamma}-phase (Ni{sub 3}Al-base intermetallic), whose content is determined mainly by the content of Al and amounts to 60 - 65% in modern alloys, plays a special role in the strengthening process. The article presents results on the phase composition of some high-temperature nickel alloys after service. The degree of degradation of the {gamma}-phase in a field of high temperatures and stresses and the degree of its recovery under the effect of regenerative heat treatment are investigated.

  6. Influence of manganese and silicon on high temperature oxidation of nickel-base heat resistant alloys in simulated VHTR helium environment

    International Nuclear Information System (INIS)

    Roles of Ma and Si in Hastelloy alloy X were examined in terms of the high temperature oxidation behavior of several experimental heats at 10000C in flowing helium containing very small amounts of impurities. Both elements were found to have significant influence both on the steady state oxidation rates, evaluated as Cr consumption rate, and on the oxide film spallation resistance. In such a special environment, characterized by very low oxygen potential, the following effects were observed: 1) Within the range (max. 1.32 wt%) tested addition of Mn improved the oxidation resistance nearly propotionally to the increase of Mn content. The effect was interpreted in formation of the outer MnCr2O4 spinel oxide layer outside the inner Cr2O3 oxide layer. 2) Addition of Si caused the similar effect on the steady state oxidation rate to the maximum (1.02 wt%) amount tested. The degree of adherence of the protective oxide film, however, was maximized at around 0.3 wt%, above and below which spallation of oxide film tended to occur with either increasing or decreasing Si content. These two could be explained in formation and morphology of the Si oxide phase in the oxide and metal interface. (author)

  7. Effect of magnesium on properties and fracture of the heat resisting KhN70VMTYu alloy

    International Nuclear Information System (INIS)

    Modern physical metallurgy techniques were used to determine the quantitative relationship between the failure structure and the magnesium content and properties of the alloy at high temperatures. With optimum magnesium concentrations, the failures are mainly toughness fractures with cup-like structure. Higher magnesium content leads to a greater number of fracture sections with failure along excess phases situated mainly along the boundaries of grains. Additional magnesium phases are formed in the alloy with 0.42% Mg

  8. Characterization of oxide layers of heat-resisting alloys in oxidizing and oxidizing/sulfidizing atmospheres by deuterium permeation measurement

    International Nuclear Information System (INIS)

    Deuterium permeation measurements are suitable to characterize the integrity of layers, which are preoxidized or in-situ oxidized on high temperature alloys. The permeation through metal alloys with a growing oxidized layer is described by a model with a time dependence of the permeation flux related to the growth of the oxide layer. The behaviour of the layers, which are oxidized at different oxidizing atmospheres, are investigated in this work. By permeation test, parabolic rate constants, impeding factors, as well as permeability, diffusivity and the solubility of deuterium for the oxide layers are obtained. The measurement are continued in sulfidizing atmosphere for testing such layers as corrosion barrier. In correlation with microstructural post examinations it is found that permeation measurement can be utilized as a method for investigating high-temperature corrosion. (orig.)

  9. Influence of the brazing parameters on microstructure and mechanical properties of brazed joints of Hastelloy B2 nickel base alloy; Influencia de los parametros de soldeo fuerte en la microestructura y propiedades mecanicas de la union de la aleacion base niquel Hastelloy B2

    Energy Technology Data Exchange (ETDEWEB)

    Sotelo, J. C.; Gonzalez, M.; Porto, E.

    2014-07-01

    A study of the high vacuum brazing process of solid solution strengthened Hastelloy B2 nickel alloy has been done. A first stage of research has focused on the selection of the most appropriate brazing filler metal to the base material and vacuum furnace brazing process. The influence of welding parameters on joint microstructure constituents, relating the microstructure of the joint to its mechanical properties, has been evaluated. Two gaps of 50 and 200 micrometers, and two dwell times at brazing temperature of 10 and 90 minutes were studied. The braze joint mainly consists of the nickel rich matrix, nickel silicide and ternary compounds. Finally, the results of this study have shown the high bond strength for small gaps and increased dwell times of 90 minutes. (Author)

  10. Effects of oxidation on the impact energy of Hastelloy S and Hastelloy C-4 Charpy V-notch specimens heated in air at 6000 to 8000C

    International Nuclear Information System (INIS)

    The 90SrF2 heat source being developed at PNL utilizes a Hastelloy S or Hastelloy C-4 outer capsule having a 0.5-in.-thick wall to contain the Hastelloy C-276 inner capsule. The primary objective of the study was to demonstrate that the air oxidation of the outer capsule that could occur during heat-source service would not degrade the ductility and Charpy impact strength of the capsule below the licensing requirements given in Section 1.1. The 90SrF2 heat source under development is intended for general-purpose use. Compatibility considerations limit the interface temperature between the 90SrF2 and Hastelloy C-276 inner capsule to a maximum of 8000C. The outer capsule surface temperature will be somewhat less than 8000C, and depending on the service, may be substantially lower. The oxidation tests were therefore carried out at 6000 to 8000C for exposures up to 10,000h to cover the range of temperature the outer capsule might expect to encounter in service. The results showed that the oxidation of Hastelloy S and Hastelloy C-4 in air at 6000 to 8000C is very slow, and both alloys form adherent oxide layers that serve to protect the underlying metal. Subsurface attack of Hastelloy S and Hastelloy C-4 due to oxidation was greater than expected, considering the slow oxidation rates of the two alloys at 6000 to 8000C. Estimates of subsurface attack, determined from micrographs of the oxidized specimens, showed erratic results and it was impossible to assign any type of rate equation to the subsurface attack. A conservative estimate of long-term effects can be made using a linear extrapolation of the test results. There were no significant differences between the room-temperature Charpy impact energy of Hastelloy S and Hastelloy C-4 specimens oxidized in air at 6000 to 8000C and control specimens heated in vacuum

  11. Tungsten powder alloys with carbide hardening as materials for reinforcing fibres in heat resistant composite materials. Communication 1.Manufacture of powder tungsten carbide-hardened alloys

    International Nuclear Information System (INIS)

    Factors affecting the possibility of stabilization in tungsten powder alloys of high-melting hardening interstitial phases (carbides, borides and nitrides of 4 group metals) are considered: presence of oxygen from the atmosphere and that asorbed on the surface of powder particles within W-MeC(MeB2, MeN) system; temperature of sintering occurrence of interstitial elements or phases interacting with oxygen more actively that the phase (HfC) that should be stabilized in the system. Measures allowing to prepare tungsten powder alloys using standard process equipment are suggested

  12. Influence of temperature, environment, and thermal aging on the continuous cycle fatigue behavior of Hastelloy X and Inconel 617

    International Nuclear Information System (INIS)

    Results are presented for strain-controlled fatigue and tensile tests for two nickel-base, solution-hardened reference structural alloys for use in several High-Temperature Gas-Cooled Reactor (HTGR) concepts. These alloys, Hastelloy X and Inconel 617, were tested from room temperature to 8710C in air and impure helium. Materials were tested in both the solution-annealed and the preaged conditios, in which aging consisted of isothermal exposure at one of several temperatures for periods of up to 20,000 h. Comparisons are given between the strain-controlled fatigue lives of these and several other commonly used alloys, all tested at 5380C. An analysis is also presented of the continuous cycle fatigue data obtained from room temperature to 4270C for Hastelloy G, Hastelloy X, Hastelloy C-276, and Hastelloy C-4, an effort undertaken in support of ASME code development

  13. High temperature low-cycle fatigue strength of Hastelloy-XR

    International Nuclear Information System (INIS)

    This paper describes the low-cycle fatigue and creep-fatigue interaction properties of Hastelloy-XR in air and helium containing a small quantity of impurity gas. All tests at temperatures of 700, 800, 900 and 1000 deg. C are carried out at the strain rate of 0.1 and 0.01%/sec under the control of axial strain. Wave forms are triangular for continuous cycling tests and trapezoidal for tension hold time tests. The test results are compared with the fatigue property of Hastelloy-X which is the original alloy of Hastelloy-XR. The applicability of linear damage rule in ASME Code Case N-47 is discussed about creep-fatigue interaction property of Hastelloy-XR in High Temperature Gas-Cooled Reactor's temperature region. (author). 6 refs, 7 figs, 2 tabs

  14. Nickel Alloy, Corrosion and Heat-Resistant, Sheet, Strip, and Plate 72Ni - 15.5Cr - 0.95 (Cb (Nb) + Ta) - 2.5Ti - 0.70Al - 7.0Fe Consumable Electrode, Remelted or Vacuum Induction Melted, Solution Heat Treated, Precipitation-Hardenable

    CERN Document Server

    SAE Aerospace Standards. London

    2012-01-01

    Nickel Alloy, Corrosion and Heat-Resistant, Sheet, Strip, and Plate 72Ni - 15.5Cr - 0.95 (Cb (Nb) + Ta) - 2.5Ti - 0.70Al - 7.0Fe Consumable Electrode, Remelted or Vacuum Induction Melted, Solution Heat Treated, Precipitation-Hardenable

  15. Investigation into thermochemical fatigue of the heat resisting VM-1 and VKh-4 alloys by the ac electric conductivity method in hydrogen atmosphere

    International Nuclear Information System (INIS)

    The process of thermal fatigue of VM-1 and VH-4 refractory alloys in vacuo and in hydrogen has been studied. Thermocycling of VM-1 alloy has been carried out at an average heating rate 140 degrees/sec, cooling rate 25 degrees/sec, that of the VH-4 alloy at 25 degrees/sec and 10 degrees/sec, both in the temperature range 300 deg - 1700 deg C. Thermoresistometric dependences for the VM-1 alloy suggest that just 3 heating-cooling cycles in hydrogen produce the same shift in recrystallization temperature as 45 cycles in vacuo. The influence of hydrogen is maximum after 20 cycles; further thermocycling hardly increases the electric resistance. Studies on thermochemical fatigue of VH-4 alloy in hydrogen atmosphere have shown that after 1 hour the alloy is kept in hydrogen the phase transition temperature undergoes a shift from 930 deg to 770 deg C. This effect is far greater than that observed in vacuo

  16. The new alloy Thermon 4972 (NiCr22W12Fe) for high temperature components of gas-cooled reactors

    International Nuclear Information System (INIS)

    A new heat resistant Fe-Ni-Cr-W alloy - Thermon 4972 - was developed within the scope of the prototype nuclear process plant project. This new alloy not only shows mechanical properties and creep rupture properties similar to those of the nickel-based alloy Inconel 617 but in addition, the new alloy forms protective oxide layers in atmospheres with very low O2 partial pressures. Experimental test results carried out in so called PNP-helium for durations up to 2000 h in the temperature range of 750 and 950 deg. C are compared with those of the alloy Inconel 617. Furthermore the mechanical properties of these two alloys as also the alloys Hastelloy X and Incoloy 800 H have been compared. (author). 5 refs, 18 figs, 2 tabs

  17. Kinetics of evaporation from the surface of refractory nickel and titanium alloys with heat resistant coatings during their irradiation by high-power pulsed ion beams

    International Nuclear Information System (INIS)

    The effect of the irradiating conditions by high-power pulsed ion beams (HPPIB) on the ablation rate was studied. The conditions of irradiation (ions of carbon and protons, ion energy E=300-600 keV, the ion current density in a pulse j=60-500 A·cm-2, pulse duration ?=50-100 ns) were realized in 'Temp' and 'Vera' accelerators. The study of the evaporation kinetics was carried out using targets manufactured from GS26NK nickel super-alloy with NiCrAlY coating and from Vt9 and VT18U titanium alloys with Zr N and TiSiB coatings. It is shown that values of the ablation rate achieve 0.04 ?m (TiSiB), 0.4 ?m (NiCrAlY), and 1 ?m (Zr N) during a pulse under the optimal conditions of HPPIB irradiation

  18. Development of Simultaneous Corrosion Barrier and Optimized Microstructure in FeCrAl Heat-Resistant Alloy for Energy Applications. Part II: The Optimized Creep-Resistant Microstructure

    Science.gov (United States)

    Pimentel, G.; Aranda, M. M.; Chao, J.; González-Carrasco, J. L.; Capdevila, C.

    2015-05-01

    The first part of this two-part study reported the possibility of simultaneously generating a dense, self-healing ?-alumina layer by thermal oxidation and a coarse-grained microstructure with a potential goodness for high-temperature creep resistance in a FeCrAl oxide dispersion-strengthened ferritic alloy that was cold deformed after hot rolling and extrusion. In this second part, the factors affecting the formation of the coarse-grained microstructure such as strain gradients induced during the rolling process are analyzed. It is concluded that larger strain gradients lead to more refined and more isotropic grain structures.

  19. The flow behavior modeling of as-extruded 3Cr20Ni10W2 austenitic heat-resistant alloy at elevated temperatures considering the effect of strain

    Scientific Electronic Library Online (English)

    Guo-Zheng, Quan; Yuan-Ping, Mao; Chun-Tang, Yu; Wen-Quan, Lv; Jie, Zhou.

    2014-04-01

    Full Text Available In order to investigate the compressive deformation behavior of 3Cr20Ni10W2 alloy, a series of isothermal upsetting experiments were carried out in the temperature range of 1203-1403 K and strain rate range of 0.01-10 s-1 on a Gleeble-1500 thermo-mechanical simulator. The results indicate that the f [...] low stress initially increases to a peak value and then decreases gradually to a steady state. The characteristics of the curves are determined by the interaction of work hardening (WH), dynamic recovery (DRV) and dynamic recrystallization (DRX). The flow stress decreases with increasing temperature and decreasing strain rate. The relationship between microstructure and processing parameters is discussed to give an insight into the hot deformation behavior of 3Cr20Ni10W2 alloy. Then, by regression analysis for constitutive equation, material constants (n, ?, ?, A and Q) were calculated for the peak stress. Further, the constitutive equation along the flow curve was developed by utilizing an eighth order polynomial of strain for variable coefficients (including n, ?, A and Q). The validity of the developed constitutive equation incorporating the influence of strain was verified through comparing the experimental and predicted data by using standard statistical parameters such as correlation coefficient (R) and average absolute relative error (AARE) that are 0.995 and 4.08% respectively.

  20. AC losses in filamentary YBCO/hastelloy

    International Nuclear Information System (INIS)

    Full text: The AC hysteresis loss of a long YBCO thin-film superconducting strip in a perpendicular AC magnetic field can be reduced by subdividing the film into narrow parallel strips (filaments). The hysteresis loss depends on the film critical current density Jc, the film thickness d, the filament width 2a and the lateral spacing L between filaments as well as on the AC magnetic field amplitude Hm. In addition, if the film is deposited onto a YSZ/hastelloy substrate to form a flexible tape, eddy current loss occurs in the hastelloy metal. The eddy current loss depends on the resistivity p of the hastelloy, the width 2w and thickness dm of the hastelloy substrate as well as on the frequency f and amplitude Hm. We have calculated the hysteresis and eddy current losses as a function of Jc, d, 2a, L, p, w, dm, f, and Hm to find optimal design parameters for a YBCO/hastelloy tape. As the AC loss is related to the loss component X'' of the AC susceptibility, we have measured X'' at different frequencies f and amplitudes Hm for several filamentary designs of YBCO/hastelloy tapes and compared our experimental results with our model calculations

  1. Weldability of the superalloys Haynes 188 and Hastelloy X by Nd:YAG

    OpenAIRE

    Graneix Jérémie; Beguin Jean-Denis; Pardheillan François; Alexis Joël; Masri Talal

    2014-01-01

    The requirements for welded aircraft parts have become increasingly severe, especially in terms of the reproducibility of the geometry and metallurgical grade of the weld bead. Laser welding is a viable method of assembly to meet these new demands, because of automation, to replace the manual TIG welding process. The purpose of this study is to determine the weldability of Hastelloy X and Haynes 188 alloys by the butt welding process with a Nd:YAG laser. To identify the influential parameters...

  2. Evaluation of Heat Checking and Washout of Heat Resistant Superalloys and Coatings for Die inserts

    Energy Technology Data Exchange (ETDEWEB)

    David Schwam; John F. Wallace; Yulong Zhu; Edward Courtright; Harold Adkins

    2005-01-30

    This project had two main objectives: (1) To design, fabricate and run a full size test for evaluating soldering and washout in die insert materials. This test utilizes the unique capabilities of the 350 Ton Squeeze Casting machine available in the Case Meal Casting Laboratory. Apply the test to evaluate resistance of die materials and coating, including heat resistant alloys to soldering and washout damage. (2) To evaluate materials and coatings, including heat resistant superalloys, for use as inserts in die casting of aluminum alloys.

  3. Air oxidation and seawater corrosion of Hastelloy S and Hastelloy C-4

    International Nuclear Information System (INIS)

    A program is currently under way at the Pacific Northwest Laboratory (PNL) to develop the data and technology needed to permit the licensing of 90SrF2 as a radioisotope heat source fuel for terrestrial applications. The WESF 90SrF2 storage capsule consists of a Hastelloy C-276 inner capsule (2 in. I.D. x 19 in. long) and a 316L stainless steel outer capsule (2-3/8 in. I.D. x 20 in. long). Preliminary experimental tests and theoretical calculations show that the WESF storage capsule is incapable of meeting current licensing requirements for heat sources that are to be used for terrestrial applications. Therefore, the DOE decision was to develop a new heat source design that would retain the existing WESF Hastelloy C-276 inner capsule and replace the current WESF outer capsule with a new outer capsule capable of meeting current licensing requirements. Based on a number of factors, Hastelloy S was selected as the outer capsule material. Hastelloy C-4 was selected as a backup material in case the Hastelloy S had to be rejected for any reason. This report summarizes the results of studies carried out to determine the effects of both air oxidation at heat source operating temperatures and seawater corrosion on the tensile properties of the outer capsule materials

  4. Alloys For Flexible Hoses In A Corrosive Environment

    Science.gov (United States)

    Macdowell, Louis G., III; Ontiveros, Cordelia

    1992-01-01

    High-nickel alloy resists pitting corrosion. Report evaluates metal alloys for flexible hoses in corrosive environment. Tested to find alternatives to 304L stainless steel. Nineteen alloys selected for testing on basis of reputation for resistance to corrosion. Top five, in order of decreasing resistance to corrosion: Hastelloy(R) C-22, Inconel(R) 625, Hastelloy(R) C-276, Hastelloy(R) C-4, and Inco(R) alloy G-3. Of these, Hastelloy(R) C-22 found best for flexible-hose application.

  5. Hydrogen permeation through heat transfer pipes made of Hastelloy XR during the initial 950 deg. C operation of the HTTR

    International Nuclear Information System (INIS)

    The permeation of hydrogen isotopes through the Hastelloy XR high-temperature alloy adopted for the heat transfer pipes of the intermediate heat exchanger in the HTTR, is one of the concerns in the hydrogen production system, which will be connected to the HTTR in the near future. The hydrogen permeation between the primary and secondary coolants through the Hastelloy XR was evaluated using the actual hydrogen concentrations observed during the initial 950 deg. C operation of the HTTR. The hydrogen permeability of the Hastelloy XR was estimated conservatively high as follows. The activation energy E 0 and pre-exponential factor F 0 of the permeability of hydrogen were E 0 = 65.8 kJ/mol and F 0 = 7.8 x 10-9 m3(STP)/(m s Pa0.5), respectively, in the temperature range from 707 to 900 K

  6. Fatigue and uniaxial deformation behavior of Hastelloy XR at elevated temperatures

    International Nuclear Information System (INIS)

    Fully reversed continuous cycling tests and tensile tests were conducted on Hastelloy XR at temperatures ranging from 600 deg C to 950 deg C in air. Fatigue life of Hastelloy XR depends on temperature. A series of SEM observation revealed that transgranular fracture with evident striation formation was dominant at temperatures below 800 deg C, while intergranular cracking was found above 900 deg C. These results suggest that creep mechanism takes place in the fatigue behavior of this alloy above 900 deg C. Numerical analyses of deformation behavior during fatigue and tensile tests were conducted to interpret the experimental results. Conventional elastic-creep constitutive equation gave a good prediction of this deformation process. (author)

  7. High-temperature and heat-resistant metal materials: physicochemical principles of development. Zharoprochnye i zharostoikie metallicheskie materialy: Fiziko-khimicheskie printsipy sozdaniia

    Energy Technology Data Exchange (ETDEWEB)

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

    1987-01-01

    The papers contained in this volume are concerned with the physicochemical fundamentals of the development of high-temperature and heat-resistant metal alloys and the structure, phase composition, and physicomechanical properties of alloys based on iron, nickel, and refractory and noble metals. The discussion covers the effect of the structural state of steels on heat resistance, structural stability of precipitation-hardening nickel alloys, and the theoretical principles of the formation of protective coatings on steels and alloys. Papers are also presented on the prospects for the protection of nickel alloys against sulfide-oxide corrosion, carbide strengthening of niobium alloys, and mechanical properties of some corrosion-resistant steels.

  8. Heat-resistant ferrochrome slag based concrete

    Directory of Open Access Journals (Sweden)

    M.T. Zuginisov

    2014-11-01

    Full Text Available In the construction materials industry, expensive refractories (fire clay, silica, high- aluminous, etc., are used as the main lining materials which despite their high fire resistance are inefficient for the use in thermal aggregates with an operation temperature up to 1300 °C. The purpose of the research was to develop heat-resistant concrete on the basis of sodium silicate binder and liquid glass with application of ferrochrome slag. Studies on the use of ferrochrome slag to obtain heat-resistant concrete are quite limited. It is common to apply self-scattered ferrochrome slag as a hardener when liquid glass is used. Carbonaceous ferrochrome slag is used when getting sodium silicate binder and as a filler together with other fire-resistant materials. Therefore, development of low-component heat-resistant concrete, which contains in the binder and filler the same raw materials with uniform-phase structure, represents a certain scientific and practical interest. On the basis of carbonaceous ferrochrome slag, sodium silicate binder and heat-resistant concrete with uniform-phase structure have been developed. Also a heat-resistant concrete mix has been developed with an application of liquid glass and without any special hardener. Curing of concrete on sodium silicate binder was carried out by drying in the range of temperatures of 100-200 ° C, curing of concrete on liquid glass was done with drying in the range of temperatures of 105±5 ??. Compression strength of concrete on sodium silicate binder after drying was 26.2 MPa, compression strength of concrete on liquid glass was 25.8 MPa.

  9. Development of heat-resistant magnetic sensor

    International Nuclear Information System (INIS)

    A heat-resistant flux gate magnetic sensor has been developed. Permendur, which has high Curie point, is employed as the magnetic core material and the detection method of the external magnetic field is modified. The characteristics of the developed magnetic sensor up to 500degC were evaluated. The sensor output increased linearly with the external magnetic field in the range of ±5 G and the standard deviation at 500degC was about 0.85G. (author)

  10. Compatibility studies of potential molten-salt breeder reactor materials in molten fluoride salts. [Inconel 601, Cr and Nb modifications of Hastelloy N

    Energy Technology Data Exchange (ETDEWEB)

    Keiser, J. R.

    1977-05-01

    The molten fluoride salt compatibility studies carried out during the period 1974--76 in support of the Molten-Salt Reactor Program are summarized. Thermal-convection and forced-circulation loops were used to measure the corrosion rate of selected alloys. Results confirmed the relationship of time, initial chromium concentration, and mass loss developed by previous workers. The corrosion rates of Hastelloy N and Hastelloy N modified by the addition of 1--3 wt percent Nb were well within the acceptable range for use in an MSBR. 13 figures, 3 tables.

  11. Electrochemical impedance spectrometry using 316L steel, hastelloy, maraging, Inconel 600, Elgiloy, carbon steel, TiN and NiCr. Simulation in tritiated water. 2 volumes

    International Nuclear Information System (INIS)

    Polarization and electrochemical impedance spectrometry curves are presented and discussed. These curves make it possible to ascertain the corrosion domains and to compare the slow and fast kinetics (voltammetry) of different stainless steel alloys. These corrosion kinetics, the actual or simulated tritiated water redox potentials, and the corrosion potentials provide a classification of the steels studied here: 316L, Hastelloy, Maraging, Inconel 600, Elgiloy, carbon steel and TiN and NiCr deposits. From the results it can be concluded that Hastelloy and Elgiloy have the best corrosion resistance. (author). 49 refs., 695 figs., tabs

  12. CORN CULTIVAR IDENTIFICATION THROUGH HEAT RESISTANT PROTEINS

    Directory of Open Access Journals (Sweden)

    SOLANGE CARVALHO BARRIOS ROVERI JOSÉ

    2004-04-01

    Full Text Available Stable and polymorphic markers are required for the identification and registration of the cultivars. The purpose of this research was to evaluate the heat resistant proteins polymorphism and stability of seeds from corn lines harvested in different years and dried under natural and artificial conditions, in order to employ such proteins in the identification and registration of the cultivars. The seeds showed different physiological quality when evaluated by germination test and the heat resistant proteins were extracted from embryonic axis from seeds of each line, in Tris-HCl 0,05 M buffer. The eletrophoretic patterns of these proteins in SDS-PAGE showed stable bands for each genotype even for the lines with higher variation in the germination test. The most similar corn inbred lines were distinguished, at least by two bands, showing that these proteins were highly polymorphic. The stability and the high level of polymorphism of the heat resistant proteins, make them potential markers in corn cultivars registration and identification programs.

  13. Heat resistance of juice spoilage microorganisms.

    Science.gov (United States)

    Shearer, Adrienne E H; Mazzotta, Alejandro S; Chuyate, Rolenda; Gombas, David E

    2002-08-01

    The heat resistance of various yeasts (Saccharomyces cerevisiae, Rhodotorula mucilaginosa, Torulaspora delbrueckii, and Zygosaccharomyces rouxii), molds (Penicillium citrinum, Penicillium roquefortii, and Aspergillus niger), and lactic acid bacteria (Lactobacillus fermentum and Lactobacillus plantarum) obtained from spoiled acid or acidified food products was determined in 0.1 M citrate buffer at pH values of 3.0, 3.5, and 4.0. S. cerevisiae was the most heat resistant of the microorganisms in citrate buffer, and its heat resistance was further evaluated in apple, grapefruit, calcium-fortified apple, and tomato juices as well as in a juice base with high fructose corn syrup. Decimal reduction times (D-values) and changes in temperature required to change the D-value (z-values) for S. cerevisiae were higher in the juices than in citrate buffer at all pH values tested. The D57 degrees C(135 degrees F)-values varied from 9.4 min in the juice product with pH 2.8 to 32 min in a calcium-added apple juice with pH 3.9. The S. cerevisiae strain used in this study can be used in thermal-death-time experiments in acidic products to calculate process conditions and in challenge tests to validate the calculated temperatures and hold times during processing. PMID:12182479

  14. Creep and rupture behavior of a special grade Hastelloy-X in simulated HTGR helium

    International Nuclear Information System (INIS)

    Creep and rupture tests were conducted for Hastelloy-XR (a modified version of the conventional Hastelloy alloy X) at 800, 900, and 10000C in simulated high-temperature gas-cooled reactor helium. Creep testing machines with special control of helium chemistry were used. As a result, the scatter of creep-rupture data could be reduced, and the variability of creep-rupture behavior due to manufacturing history could be resolved. Results of metallography and carbon analysis of ruptured specimens showed that the material improved resistance to corrosion in the helium environment, and carbon intrusion during the steady-state creep stage was suppressed to a negligible level. Under refined test conditions combined with the quality controlled material, it was demonstrated that there was little significant difference between helium and air in the creep-rupture results obtained at 800 to 10000C up to about 104h. The importance of maintaining the protective function of the surface oxide film of alloys was stressed in securing reproducibility and predictability of long-time creep performance

  15. Effect of temperature and strain rate on serrated flow behaviour of Hastelloy X

    International Nuclear Information System (INIS)

    Highlights: ? Tensile serrated flow behaviour of Hastelloy X was examined. ? A, A + B, B and C types of serrated flow behaviour have been observed. ? Molybdenum solute has been found to be responsible for serrated flow behaviour. ? M6C, M23C6 and ?-phase were observed at higher temperatures. - Abstract: Serrated flow behaviour of Hastelloy X has been examined over a wide range of temperature (300–1023 K) and strain rate (3 × 10?3s?1 to 3 × 10?5s?1). The alloy exhibited different types of tensile serrated flow in the intermediate temperature range of 473–923 K. Normal portevin-Le Chatelier effect (PLE) exhibiting type A and B serrations were observed at temperatures less than 823 K and inverse PLE exhibiting type C serrations was noticed at temperatures above 823 K. The average activation energy value of 106 kJ mol?1 for the A and B types of serrated flow has been evaluated. The evaluated activation energy value revealed that the migration of molybdenum in the nickel matrix has been found to be responsible for the occurrence of serrated flow in the alloy.

  16. Compatibility of aluminide-coated Hastelloy X and Inconel 617 in a simulated gas-cooled reactor environment

    International Nuclear Information System (INIS)

    Commercially prepared aluminide coatings on Hastelloy X and Inconel 617 substrates were exposed to controlled-impurity helium at 850 and 9500C for 3000 h. Optical microscopy, scanning electron microscopy (SEM), electron microprobe profiles and SEM X-ray mapping were used to evaluate and compare exposed and unexposed control samples. Four coatings were evaluated: aluminide, aluminide with platinum, aluminide with chromium, and aluminide with rhodium. With extended time at elevated temperature, nickel diffused into the aluminide coatings to form epsilon phase (Ni3Al). This diffusion was the primary cause of porosity formation at the aluminide-alloy interface. Aluminide coatings with chromium (HI-15) showed the lowest coating-substrate interface porosity and intermetallic phase growth. The presence of excess chromium in the HI-15-aluminide-coated Hastelloy X sample is believed to have compensated partially for the nickel loss by its diffusion into the nickel-depleted coating-substrate transition zone. None of the other coating additions had an obvious effect on the overall behavior of aluminide-coated Hastelloy X or Inconel 617 in the impure helium environment. The exterior of the aluminide coatings was not visually affected by the impure helium. Carbide precipitation below the coating-substrate interface, resulting from carbon ingress from the helium environment, was observed in uncoated control samples. Carburization of aluminide-coated substratesrburization of aluminide-coated substrates was less extensive than that of uncoated materials and was related to the degree of porosity at the coating-alloy interface. (Auth.)

  17. Effect of cold work on creep properties of Hastelloy XR

    International Nuclear Information System (INIS)

    Creep tests of Hastelloy XR, in 10%, 20% cold worked or solution treated condition, were made at 800 at 1000degC for times up to about 2000 ks in order to investigate the effect of cold work on creep properties. The results obtained are as follows: (1) Below 950degC, creep rupture strength of 10% cold worked Hastelloy XR is beyond the value of solution treated one within this experimental condition. 950degC and cold work of 10% are the highest values experienced in an intermediate heat exchanger of the High Temperature Engineering Test Reactor(HTTR) under normal condition, respectively. (2) At 800 and 850degC, creep rupture time of 20% cold worked Hastelloy XR is longer than that of solution treated one. However, the effect disappears above 900degC. At 950 and 1000degC, it becomes shorter than that of solution treated Hastelloy XR. (3) Rupture elongation and reduction of area of cold worked Hastelloy XR are smaller than those of solution treated one. While these values of 10% or 20% cold worked material are lowest at 900degC, they recover considerably at 1000degC. (4) Minimum creep rate, ?m, of 10% or 20% cold worked Hastelloy XR is decreased by as much as a factor of 20 to 50 at 800 to 900degC. On the other hand, ?m of 10% or 20% cold worked material is increased at 1000degC. (5) From the results of microstructure observation of ruptured specimens, decrease in creep rupture strength of cold worked Hastelloy XR is interpreted in terms of extensive recrystallization which occurs during creep at 1000degC. (author)

  18. Thermophysical Properties of Heat Resistant Shielding Material

    Energy Technology Data Exchange (ETDEWEB)

    Porter, W.D.

    2004-12-15

    This project was aimed at determining thermal conductivity, specific heat and thermal expansion of a heat resistant shielding material for neutron absorption applications. These data are critical in predicting the structural integrity of the shielding under thermal cycling and mechanical load. The measurements of thermal conductivity and specific heat were conducted in air at five different temperatures (-31 F, 73.4 F, 140 F, 212 F and 302 F). The transient plane source (TPS) method was used in the tests. Thermal expansion tests were conducted using push rod dilatometry over the continuous range from -40 F (-40 C) to 302 F (150 C).

  19. Optimization in Si content of hastelloy XR for oxidation resistance and oxide film adherence during oxidation in VHTR helium

    International Nuclear Information System (INIS)

    Oxidation behavior of several heats of modified Hastelloy alloy X, named Hastelloy XR, with different Si contents was examined in isothermal, thermal cycling exposure tests. The test environment was flowing helium at 10000C containing controlled amounts of impurities simulating the Very High Temperature gas-cooled Reactor (VHTR) coolant. Tests were made to determine an optimization rang of Si content for obtaining higher resistance to the oxidation and less oxide spallation in the service environment. Up to 1% content, increase of the Si caused decrease of the oxidation rate, while the oxide spallation in thermal cycling was a minimum in the range of about 0.2 to 0.4% Si. These two could be explained in formation and morphology of the SiO2 phase in the oxide and metal interface by metallographic observation and analysis. (author)

  20. Electrochemical impedance spectrometry using 316L steel, hastelloy, maraging, Inconel 600, Elgiloy, carbon steel, TiN and NiCr. Simulation in tritiated water. 2 volumes; Spectrometrie d`impedance electrochimique sur acier 316L, hastelloy, maraging inconel 600, elgiloy, acier au carbone, TiN, NiCr. Simulations en eau tritiee. 2 volumes

    Energy Technology Data Exchange (ETDEWEB)

    Bellanger, G.

    1994-03-01

    Polarization and electrochemical impedance spectrometry curves are presented and discussed. These curves make it possible to ascertain the corrosion domains and to compare the slow and fast kinetics (voltammetry) of different stainless steel alloys. These corrosion kinetics, the actual or simulated tritiated water redox potentials, and the corrosion potentials provide a classification of the steels studied here: 316L, Hastelloy, Maraging, Inconel 600, Elgiloy, carbon steel and TiN and NiCr deposits. From the results it can be concluded that Hastelloy and Elgiloy have the best corrosion resistance. (author). 49 refs., 695 figs., tabs.

  1. Creep of heat resisting materials under thermal cycling

    International Nuclear Information System (INIS)

    Investigation results for creep of heat resisting materials (0Kh16N15M3B austenitic steel, the ZhS-6U nickel base alloy) under thermal cycling conditions are presented. The investigations have been carried out at the constant temperature and under conditions of saw-like temperature cycle at the constant load. Cyclic tests of the austenitic steel have been carried out in the temperature range of 400 reversible 700 deg C, the ZhS-6U alloy has been tested in the temperature range of 600 reversible 1100 deg C. Expe netal confirmation of the suggested conception of the account of cyclic change of the mechanical properties of the material under conditions of non-isothermal creep is obtained. Application possibility for the hypothesis of the transformed time to calculate the steady creep rate under thermal cycling conditions according to the results of isothermal tests for the materials having weak dependence of the yield limit on the temperature is shown

  2. Low-cycle fatigue of Hastelloy X and Hastelloy XR in simulated VHTR helium coolant environment at elevated temperature

    International Nuclear Information System (INIS)

    Strain-controlled low-cycle fatigue tests were conducted on Hastelloy X and its modified version, Hastelloy XR, at 900 sup( o)C in the flowing simulated VHTR helium environment. The results of this study provide the following conclusions; 1) Hastelloy X and Hastelloy XR exhibited essentially the same low-cycle fatigue characteristics under the given test conditions, where marked difference was observed in the oxidation performance between those materials. The results obtained in the present work were in good accordance with the following equation proposed by Manson and Coffin ? epsilon sub(t) = ? epsilon sub(e) + ? epsilon sub(p) = 0.00228 Nsub(f)sup(-0.00732) + 0.447 Nsub(f)sup(-0.604) 2) The ratio of Nsup(f) in impure helium to Nsup(f) in 1--3 x 10-6 Pa vacuum were examined, and the results were equally about 0.7 for both materials. 3) Both transgranular fracture mode with ductile striations and intergranular fracture mode were recognized in the fracture surfaces, with the former mode being predominant. 4) The results obtained in the present work were situated on the line corresponding to the approximate average level of the available fatigue data in literature on Hastelloy X tested under similar test conditions. (author)

  3. Heat resistance of Fe-Al intermetallics in the context of selected heat-resistant and hihg-temperature creep resistant steels

    Directory of Open Access Journals (Sweden)

    P. Baranowski

    2009-04-01

    Full Text Available Results are hereby presented of heat-resistance tests of two Fe3Al and FeAl intermetallic phase-based alloys in the context of St41k-typeboiler steel and 50H21G9N4 high-temperature creep resistant steel. It has been ascertained that heat resistance of the 50H21G9N4 steeland of the Fe3Al and FeAl intermetallic phase-based alloys significantly exceeds that of the boiler steel tested in the air atmosphere and the atmosphere of a flue gas with CO, CO2, SiO2 content alike. Improvement of these properties depends of exposure conditions. The largest differences have been observed when the tests were carried out in temperature 1023 K and in the flue gas atmosphere. The differences have been more and more noticeable as the exposition duration extended. A tendency has been also recorded of smaller mass decrements of the Fe3Al and FeAl intermetallic phase-based alloys as compared to the 50H21G9N4 steel.

  4. Heat resistant concrete (Rhine sand concrete)

    International Nuclear Information System (INIS)

    The heat resistant concrete has a fresh concrete density of at least 2300 kg/m3, a great strength in the temperature range 200 to 3000C, and is intended for prestressed concrete reactor pressure vessels, for nuclear reactors, particularly high temperature reactors. It consists of a quantity of hydraulic cement with water, concrete additives of quartz and flyash as additives and to delay solidification and concrete liquifier as additive. For a water cement value of 0.40, the quantity has a fine grain content of 29% of the additive. The flyash and finely divided quartz grain content causes a rise in strength in hydrothermal conditions, which counteracts the loss of strength due to temperature effects. (orig./PW)

  5. Fundamental studies on electron beam welding of heat-resistant superalloy for nuclear plants, (2)

    International Nuclear Information System (INIS)

    In the previous report, it was described that the defects occurred in electron beam welds were porosity and microcracks which ran approximately perpendicular to the fusion lines and were found much in the nailhead area. In this report, the consideration and investigation have been carried out on the mechanism of weld crack generation. As the metallurgical studies, observation of the structure of heat-affected zones adjacent to the fusion lines of electron beam welds with a scanning electron microscope, composition analysis of the precipitates with an X-ray microanalyzer and identification of the precipitates by X-ray diffraction have been carried out, using Hastelloy-group, Inconel-group and Incoloy-group heat-resistant superalloys for nuclear plants, and austenitic stainless steel for comparison. Further, the temperature, stress and strain distribution in heat-affected zone adjacent to the fusion line of a model has been analyzed, which has been provided to simulate the conditions in the processes of electron beam welding. As a result, it has been clarified that such microcracks were mainly caused by both melting of precipitates in the heat-affected zone adjacent to the fusion line, and the behaviors of temperature, stress and strain distributions in the nailhead area peculiar to electron beam welding. (Wakatsuki, Y.)

  6. Effects of gaseous environments in gas-cooled reactors and solar thermal heat exchangers on the creep and creep-rupture properties of heat-resisting metals and alloys. Final report

    International Nuclear Information System (INIS)

    Energy conversion systems employing heat exchangers use closed cycle gas turbines with helium as the working fluid. An important design criterion for heat exchanger and turbine systems is the creep strength of the tubing, blading, and vane materials. The design data for these materials generally has been obtained in air. However, there have been reports of adverse environmental effects of helium on the creep strength and ductility of these materials. Much of the environmental data has been obtained using relatively impure helium from high temperature helium-cooled reactor systems (HTGR's). However, power conversion systems using coal or solar energy as the heat source would use commercially pure helium, not subject to the carbonaceous gases that are picked up when helium is used as the coolant for the HTGR's. Stanford University was asked to summarize the environmental effects of helium on the creep properties of heat exchanger alloys. Also, they were asked to conduct critical experiments under what ought to probably be the worst conditions, based on the literature, to determine the maximum extent of the environmental effect. It was found that the environmental effects reported in the literature are relatively small, not more than a factor of two in rupture time or creep rate, which is within the usual experimental scatter and in heat-to-heat variations. The experimental work reported on a HA188 confirmed this conclusion

  7. Hemispherical total emissivity of Hastelloy N with different surface conditions

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, Andrew J.; Walton, Kyle L. [Particulate Systems Research Center, Nuclear Science and Engineering Institute, University of Missouri, Columbia, MO 65211 (United States); Ghosh, Tushar K., E-mail: ghoshT@missouri.edu [Particulate Systems Research Center, Nuclear Science and Engineering Institute, University of Missouri, Columbia, MO 65211 (United States); Loyalka, Sudarshan K.; Viswanath, Dabir S.; Tompson, Robert V. [Particulate Systems Research Center, Nuclear Science and Engineering Institute, University of Missouri, Columbia, MO 65211 (United States)

    2012-07-15

    The hemispherical total emissivity of Hastelloy N (a candidate structural material for Next Generation Nuclear Plants (NGNPs), particularly for the molten fluoride cooled reactors) was measured using an experimental set-up that was constructed in accordance with the standard ASTM C835-06. The material surface conditions included: (i) 'as received' (original) sample from the supplier; (ii) samples with increased surface roughness through sand blasting; (iii) oxidized surface, and (iv) samples coated with graphite powder. The emissivity of the as received samples varied from around 0.22 to 0.28 in the temperature range of 473 K to 1498 K. The emissivity increased when the roughness of the surface increased compared to an as received sample. When Hastelloy N was oxidized in air at 1153 K or coated with graphite powder, its emissivity increased substantially. The sample sand blasted with 60 grit beads and sprinkled with graphite powder showed an increase of emissivity from 0.2 to 0.60 at 473 K and from 0.25 to 0.67 at 1473 K. The oxidized surface showed a similar behavior: an increase in emissivity compared to an unoxidized sample. This increase in emissivity has strong favorable safety implications in terms of decay heat removal in post-accident environments. The data were compared with another Hastelloy family member, Hastelloy X.

  8. Hemispherical total emissivity of Hastelloy N with different surface conditions

    International Nuclear Information System (INIS)

    The hemispherical total emissivity of Hastelloy N (a candidate structural material for Next Generation Nuclear Plants (NGNPs), particularly for the molten fluoride cooled reactors) was measured using an experimental set-up that was constructed in accordance with the standard ASTM C835-06. The material surface conditions included: (i) ‘as received’ (original) sample from the supplier; (ii) samples with increased surface roughness through sand blasting; (iii) oxidized surface, and (iv) samples coated with graphite powder. The emissivity of the as received samples varied from around 0.22 to 0.28 in the temperature range of 473 K to 1498 K. The emissivity increased when the roughness of the surface increased compared to an as received sample. When Hastelloy N was oxidized in air at 1153 K or coated with graphite powder, its emissivity increased substantially. The sample sand blasted with 60 grit beads and sprinkled with graphite powder showed an increase of emissivity from 0.2 to 0.60 at 473 K and from 0.25 to 0.67 at 1473 K. The oxidized surface showed a similar behavior: an increase in emissivity compared to an unoxidized sample. This increase in emissivity has strong favorable safety implications in terms of decay heat removal in post-accident environments. The data were compared with another Hastelloy family member, Hastelloy X.

  9. Machinability of hastelloy C-276 using Hot-pressed sintered Ti(C7N3)-based cermet cutting tools

    Science.gov (United States)

    Xu, Kaitao; Zou, Bin; Huang, Chuanzhen; Yao, Yang; Zhou, Huijun; Liu, Zhanqiang

    2015-05-01

    C-276 nickel-based alloy is a difficult-to-cut material. In high-speed machining of Hastelloy C-276, notching is a prominent failure mode due to high mechanical properties of work piece, which results in the short tool life and low productivity. In this paper, a newly developed Ti(C7N3)-based cermet insert manufactured by a hot-pressing method is used to machine the C-276 nickel-based alloy, and its cutting performances are studied. Based on orthogonal experiment method, the influence of cutting parameters on tool life, material removal rates and surface roughness are investigated. Experimental research results indicate that the optimal cutting condition is a cutting speed of 50 m/min, depth of cut of 0.4 mm and feed rate of 0.15 mm/r if the tool life and material removal rates are considered comprehensively. In this case, the tool life is 32 min and material removal rates are 3000 mm3/min, which is appropriate to the rough machining. If the tool life and surface roughness are considered, the better cutting condition is a cutting speed of 75 m/min, depth of cut of 0.6 mm and feed rate of 0.1 mm/r. In this case, the surface roughness is 0.59?m. Notch wear, flank wear, chipping at the tool nose, built-up edge(BUE) and micro-cracks are found when Ti(C7N3)-based cermet insert turned Hastelloy C-276. Oxidation, adhesive, abrasive and diffusion are the wear mechanisms, which can be investigated by the observations of scanning electron microscope and energy-dispersive spectroscopy. This research will help to guide studies on the evaluation of machining parameters to further advance the productivity of nickel based alloy Hastelloy C-276 machining.

  10. Metallurgical and environmental factors influencing creep behaviour of hastelloy-X

    International Nuclear Information System (INIS)

    Creep and rupture behaviours of Hastelloy-X and its modified version were examined with special reference to the effect of different test environments; i.e. air, high vacuum and the simulated HTR helium coolant. The respective environments showed different effects. The vacuum environment of about 10-8 torr. gave best reproducible behaviour with essentially no surface-to-volume ratio effect. Such size effect was significant in the other two environments. The simulated HTR environment was characterized in its potentiality of both oxidizing selected alloy constituents and carburization. The observed behaviour was attributed to the depletion of strengthning solute elements caused by the surface reactions and the associated solid state reactions. (author)

  11. Effect of strain rate on high-temperature low-cycle fatigue behavior of hastelloy X and hastelloy XR

    International Nuclear Information System (INIS)

    A series of strain controlled low-cycle fatigue tests at 900 deg C in the simulated HTGR helium environment were conducted on Hastelloy X and its modified version, Hastelloy XR, and the effect of strain rate on high-temperature low-cycle fatigue behavior was investigated. The results of this study provide the following conclusions; (1) Decreasing the strain rate led to notable reductions in the fatigue life. (2) Trends of strain softening and cyclic softening were observed at lower strain rates of 1 x 10-4 s-1 and 2 x 10-5 s-1. (3) Both fracture modes of the transgranular and the intergranular were recognized on the fracture surfaces, with the former mode being predominant at a comparatively high strain rate of 1 x 10-3 s-1. The intergranular fracture mode, however, became predominant at lower strain rates, 1 x 10-4 s-1 and 2 x 10-5 s-1. (4) The cumulative damage rule predicted an excessively coservative value for creep damage. (5) The data obtained lay on the straight line plots when the frequency modified fatigue life method was applied. No significant difference in fatigue behavior was resolved between Hastelloy X and Hastelloy XR under the test conditions employed. (author)

  12. Compatibility of aluminide-coated Hastelloy x and Inconel 617 in a simulated gas-cooled reactor environment

    International Nuclear Information System (INIS)

    Commercially prepared aluminide coatings on Hastelloy X and Inconel 617 substrates were exposed to controlled-impurity helium at 8500 and 9500C for 3000 h. Optical and scanning electron (SEM) microscopy, electron microprobe profiles, and SEM X-ray mapping were used to evaluate and compare exposed and unexposed control samples. Four coatings were evaluated: aluminide, aluminide with platinum, aluminide with chromium, and aluminide with rhodium. With extended time at elevated temperature, nickel diffused into the aluminide coatings to form epsilon-phase (Ni3Al). This diffusion was the primary cause of porosity formation at the aluminide/alloy interface

  13. ISOLATION OF HEAT RESISTANT FUNGI FROM CANNED FRUITS

    Directory of Open Access Journals (Sweden)

    Sani Ibrahim

    2014-05-01

    Full Text Available -Increase in the consumption of canned fruit juice rather than the fruit itself raises alarmonto the safety of these canned juices as they are stored for longer period of time unlike the fruit and dormant if spores present could germinate and cause spoilage. Heat-resistant molds are characterized by the production of ascospores or similar structures with heat resistance, in some instances comparable to bacterial spores. This enables them to survive even when they are thermally processed.

  14. Analyzing the effect of cutting parameters on surface roughness and tool wear when machining nickel based hastelloy - 276

    International Nuclear Information System (INIS)

    Machining parameters has an important factor on tool wear and surface finish, for that the manufacturers need to obtain optimal operating parameters with a minimum set of experiments as well as minimizing the simulations in order to reduce machining set up costs. The cutting speed is one of the most important cutting parameter to evaluate, it clearly most influences on one hand, tool life, tool stability, and cutting process quality, and on the other hand controls production flow. Due to more demanding manufacturing systems, the requirements for reliable technological information have increased. For a reliable analysis in cutting, the cutting zone (tip insert-workpiece-chip system) as the mechanics of cutting in this area are very complicated, the chip is formed in the shear plane (entrance the shear zone) and is shape in the sliding plane. The temperature contributed in the primary shear, chamfer and sticking, sliding zones are expressed as a function of unknown shear angle on the rake face and temperature modified flow stress in each zone. The experiments were carried out on a CNC lathe and surface finish and tool tip wear are measured in process. Machining experiments are conducted. Reasonable agreement is observed under turning with high depth of cut. Results of this research help to guide the design of new cutting tool materials and the studies on evaluation of machining parameters to further advance the productivity of nickel based alloy Hastelloy - 276 machininickel based alloy Hastelloy - 276 machining.

  15. Feasibility of EB Welded Hastelloy X and Combination of Refractory Metals

    Science.gov (United States)

    Martinez, Diana A.

    2004-01-01

    As NASA continues to expand its horizon, exploration and discovery creates the need of advancement in technology. The Jupiter Icy Moon Orbiter's (JIMO) mission to explore and document the outer surfaces, rate the possibility of holding potential life forms, etc. within the three moons (Callisto, Ganymede, and Europa) proves to be challenging. The orbiter itself consists of many sections including: the nuclear reactor and the power conversion system, the radiator panels, and the thrusters and antenna. The nuclear reactor serves as a power source, and if successfully developed, can operate for extended periods. During the duration of my tenure at NASA Glenn Research Center's (NASA GRC) Advanced Metallics Branch, I was assigned to assist Frank J. Ritzert on analyzing the feasibility of the Electron Beam Welded Hastelloy X (HX), a nickel-based superalloy, to Niobium- 1 %Zirconium (Nb-1 Zr) and other refractory metals/alloys including Tantalum, Molybdenum, Tungsten, and Rhenium alloys. This welding technique is going to be used for the nuclear reactor within JIMO.

  16. Thermal response of heat-resistant layer with pyrolysis

    Directory of Open Access Journals (Sweden)

    Huang Haiming

    2012-01-01

    Full Text Available A model is developed for analyzing the thermal response of the heat-resistant layer composed of high silica fiber reinforced phenolic matrix composites(SiO2/P and aluminum, in which pyrolysis and phase transitions are exsited, such as melt, vaporization and sublimation. Based on this model, the thermal response of the heat-resistant layer with different SiO2/P thickness is calculated under a heat flux by using FORTRAN codes. As indicated in the results, the slope of temperature gets a sudden decline at the pyrolysis interface, which is due to the latent heat of pyrolysis; the thickness of heat-resistant layer has little influence on the heating-surface temperature, however, the back temperature may increase with the decreasing thickness; and the thermal conductivity of carbonized layer is very important to thermal response.

  17. Study on the heat-resistant EB curing composites

    International Nuclear Information System (INIS)

    There are many advantages in the EB-curing process of composites. Heat-resistant EB-curing composites could substitute for polyimide composites used in aeronautical engine. The effects of catalyst and dose on the cured resin were investigated. The heat-resistance of the resin cured by EB was evaluated by dynamic mechanical thermal analysis (DMTA). The experiment result shows that the mechanical property of the composites cured by EB could meet the needs of the aeronautical engine in 250degC. (author)

  18. High temperature strength of hastelloy x welded joints

    International Nuclear Information System (INIS)

    In the design of high temperature structures such as ASME Code N-47, the high temperature strength characteristics of welded joints become the problem. Also, the design of the welded parts in high temperature structures in the present state is according to the standard in which the bimetallic behavior of welded parts is not considered, accordingly, it is much problematic. In this paper, the high temperature strength characteristics of Hastelloy X welded joints are described, and the problems in the present design are pointed out, moreover, some comment is given to the evaluation of high temperature strength for the future. In the ASME Code, Case N-47, the strength of welded joints is required to be the same as that of parent metals. Therefore, the data on the high temperature strength of welded joints must be collected. The results of tensile test at room temperature, 700, 800, 900 and 1000 deg C on the parent metal and EB and TIG welded joints of Hastelloy X are shown. Also, the characteristics of mono-axial creep rupture, internal pressure creep rupture, and high temperature, low cycle fatigue are reported. The lowering of strength in the tension, creep and fatigue of welded joints must be examined and evaluated in view of the combined behavior of parent metals and weld metals. (Kako, I.)

  19. Determination of J-integral R-curves for Hastelloy X and Inconel 617 up to 1223 K using the potential drop technique

    International Nuclear Information System (INIS)

    ror Hastelloy X (T = 308 K and T = 1223 K) and for Inconel 617 (T = 308 K, 473 K, 673 K, 873 K, 973 K, 998 K, 1023 K, 1048 K, 1073 K, 1173 K, and 1223 K) the J-integral R-curves have been determined. For Hastelloy X at 308 K the multispecimen technique has been compared with the single specimen method using the potential drop technique. At 1223 K Hastelloy X delivered a low J0-integral value. Inconel 617 showed a smooth increase in J0 with increasing temperature, up to 998 K; above this temperature ven for large loadline displacements only blunting behaviour has been observed. The same tendency has been found for the evaluation of the tearing modulus. With increasing temperature the tearing modulus increases. In the temperature range from 998 to 1223 K the tearing modulus increases by about one order of magnitude. For both alloys the onset of stable crack growth in most cases is earlier than the load maximum is reached in the load versus load-line displacement curves. (orig.)

  20. Humidity affects genetic architecture of heat resistance in Drosophila melanogaster

    DEFF Research Database (Denmark)

    Bubliy, Oleg A; Kristensen, Torsten Nygård

    2012-01-01

    Laboratory experiments on Drosophila have often demonstrated increased heritability for morphological and life-history traits under environmental stress. We used parent-offspring comparisons to examine the impact of humidity levels on the heritability of a physiological trait, resistance to heat, measured as knockdown time at constant temperature. Drosophila melanogaster were reared under standard nonstressful conditions and heat-shocked as adults at extreme high or low humidity. Mean knockdown time was decreased in the stressful dry environment, but there was a significant sex-by-treatment interaction: at low humidity, females were more heat resistant than males, whereas at high humidity, the situation was reversed. Phenotypic variability of knockdown time was also lower in the dry environment. The magnitude of genetic correlation between the sexes at high humidity indicated genetic variation for sexual dimorphism in heat resistance. Heritability estimates based on one-parent-offspring regressions tended to be higher under desiccation stress, and this could be explained by decreased environmental variance of heat resistance at low humidity. There was no indication that the additive genetic variance and evolvability of heat resistance differed between the environments. The pattern of heritability estimates suggests that populations of D. melanogaster may have a greater potential for evolving higher thermal tolerance under arid conditions.

  1. R and D of the heat-resistant LH antenna

    International Nuclear Information System (INIS)

    Two different types of Lower Hybrid Current Drive (LHCD) antenna having high-heat resistant property are developed according to a pulse length and/or working frequency. In the first type of LH antenna, heat resistive material is installed at the antenna mouth only and should be attachable using bolts. This heat-resistant mouth is exchanged for a new one when it is damaged. The heat-resistant mouth is made of Carbon Fiber Composite (CFC)-block bonded with stainless steel-base machined to fit the waveguides. This mouth has no Cu-plating for reducing rf-losses, because the antenna is designed to operate during 10-100 s injection of 2 GHz in JT-60SC. The second antenna consists of a compact multi-junction (MJ) part and a power divider designed for the next generation tokamak machine like ITER. This MJ must be made of low-Z material as a plasma facing component allowing no degradation in confinement. The test module for the MJ is made of rods and plates of CFC with Cu-plating ?30 cm in length. The test module shows transmitted power availability up to 45 MW/m2 over 1000 s with cooling at 3.7 GHz. For improvement of transmitted power availability, R and D of strong Cu-plating on CFC surface has been progressed using an electrochemical method

  2. Effect of Si on decarburization and carburization of heat-resisting austenitic steels in an impure helium

    International Nuclear Information System (INIS)

    The influence of Si on the decarburization and carburization of heat-resisting austenitic alloys were investigated in the temperature range from 800 to 10000C in an impure helium atmosphere. This atmosphere simulates the primaly coolant of high temperature gas cooled reacter. The results were as follows. The alloys with 0.5 -- 0.6 wt % Si were heavily carburized or decarburized above 9000C depending on the temperatures tested, while the carburization and decarburization of the alloy with 3.4 wt % Si were negligible small in the tested temperature range. In the alloy with high Si content, the carburization or decarburization was suppressed, because a thin SiO2 film, having a strong corrosion-resistant properties, might be formed beneath the surface-layer of (Mn, Cr) oxide. However, the films defoliate the surface oxide layers on cooling. (author)

  3. Weldability of the superalloys Haynes 188 and Hastelloy X by Nd:YAG

    Directory of Open Access Journals (Sweden)

    Graneix Jérémie

    2014-01-01

    Full Text Available The requirements for welded aircraft parts have become increasingly severe, especially in terms of the reproducibility of the geometry and metallurgical grade of the weld bead. Laser welding is a viable method of assembly to meet these new demands, because of automation, to replace the manual TIG welding process. The purpose of this study is to determine the weldability of Hastelloy X and Haynes 188 alloys by the butt welding process with a Nd:YAG laser. To identify the influential parameters of the welding process (laser power, feed rate, focal diameter and flow of gas while streamlining testing, an experimental design was established with the CORICO software using the graphic correlation method. The position of the focal point was fixed at 1/3 of the thickness of the sheet. The gas flow rate and the power of the beam have a major effect on the mechanical properties and geometry of the weld. The strength of the weld is comparable to that of the base metal. However, there is a significant decrease in the elongation at break of approximately 30%. The first observations of the cross section of the weld by scanning electron microscopy coupled with EBSD analysis show a molten zone presenting dendritic large grains compared to the equiaxed grains of the base metals without a heat affected zone.

  4. Developmentof plaster compositions that have improved heat resistance ?????????? ??????????? ???????? ?????????? ??????????????

    Directory of Open Access Journals (Sweden)

    Akulova Mariya Vladimirovna

    2013-02-01

    Full Text Available Protection of structures and materials from the adverse effects of the environment is a relevant challenge to be tacked both by the teams of researchers and workers on site. A universal method of protection contemplates the use of cladding and paints. There are classes of finishing materials that have special protective properties.Flame-resistant finishes obstruct the burning of structures, and in some cases they can even prevent inflammation. A universal method of protection is the plastering of the surface of a structure. Plastering is applicable to concrete, masonry, metal as well as timber. Development of heat resistant plaster is relevant due to numerous fires in Russia.This article represents an overview of the research into the influence of composite binders and fillers onto the physical and mechanical properties of the heat resistant plaster.Portland cement M 500 was used as a composite binder. Liquid sodium water glass with the density of 1,300 – 1,500 kg/m3 and the silicate modulus value of 2.4 – 2.8 was also applied. Glass sand with the fineness of 0.315 – 1.25, mineral wool fibers that were4 - 6 mm long (with the density of 50 kg/m3 were applied as fillers.Sugar is known as an excellent inhibitor of Portland cement. Liquid glass binders are very effective if added to heat resistant concretes and mortars. This fact was mentioned in the works of K.D. Nekrasov, A.P. Tarasov, G.P. Gorlov, B.D. Toturbiev and others, and it has been proven in practice. It is noteworthy that liquid glass demonstrates high adhesive strength in terms of all materials. Its adhesive strength is 3...5 times higher than that of the cement, and this fact can serve as the basis for the development of highquality heat-resistant solutions.The resulting composition is an excellent heat resistant plaster; its physical-mechanical and thermal properties are not inferior to heat resistant mortars based on imported additives.??????????? ???????? ?????????? ?????????????? ???????? ?????????? ????????? ?????? ???????????? ??????????? ?? ??????????? ?????????? ??????????. ????????? ???????????? ??????? ???????? ? ????????????, ????????? ????????????? ??????????? ????????????? ? ??????? ???????? ?????????? ???????????? ??? ???? ??????????. ???????? ??????????? ????????, ?????????????? ??????? ? ???? ????, ??? ? ???????? ????????.

  5. AC losses of YBCO strips on YSZ/hastelloy substrates

    Science.gov (United States)

    Herrmann, J.; Müller, K.-H.; Savvides, N.; Gnanarajan, S.; Thorley, A.; Katsaros, A.

    The effect of subdividing superconducting YBCO films on YSZ-buffered hastelloy substrates into arrays of parallel strips on the AC loss was investigated. Measurements of the loss component of the AC susceptibility, ??, revealed that the frequency-independent hysteretic contribution to ??, which is dominant at low frequencies ( f ? 1 kHz), decreased by a factor 1/ N when the film was subdivided into N parallel strips. As the strips were made wider or the separation between them made smaller, the hysteretic ?? increased. The eddy current contribution to ??, which originates from the metallic substrate, was found to become dominant with increasing frequency and approached a linear frequency dependence at high frequencies. The experimental findings are in close agreement with theoretical predictions of the AC loss in x-arrays of YBCO strips on metallic substrates.

  6. Martensite-austenite transformation kinetics of high Cr ferritic heat-resistant steel

    International Nuclear Information System (INIS)

    The isochronal transformation behavior from martensite (?') to austenite (?) of modified high Cr ferritic heat-resistant steel was analyzed using the kinetic information extracted from differential thermal analysis results. The thus obtained ?' ? ? transformation kinetic process has been described by a JMAK-like model including three overlapping processes: site saturation nucleation, diffusion-controlled growth, and impingement correction for random distribution of nuclei. It is found that both the diffusion of alloying components and the inhibition of carbide precipitates strongly affect the ?' ? ? transformation kinetic processes. The ?' ? ? transformation (at relatively low heating rates) is of diffusion-controlled nature, and the obstruction of carbides during the migration of the ?'/? interface leads to a decrease in the pre-exponential factor of diffusion coefficient. (orig.)

  7. Comparative evaluation of the fracture toughness of heat-resisting steels in creep conditions

    International Nuclear Information System (INIS)

    An approach to the evaluation of the fracture toughness of heat-resistant steels is proposed which employs an energy parameter (Jc integral) determined at the final stage of fracture. The method is demonstrated by applying it to 15Kh1M1FL steel in creep. It is shown that the fracture toughness of the steel in the temperature range 510-565 C is largely determined by its initial structure. It is also shown that a reduction of the yield stress during long-term service is not accompanied by an adequate increase in fracture toughness, which is explained by the embrittlement of the alloy during long-term service. 6 references

  8. Heat resistant driving coil and control rod drive mechanism

    International Nuclear Information System (INIS)

    Ceramic materials are used for each part of driving coils and used as the driving coils for a driving shaft. That is, a cylindrical bobbin having outwardly protruding flanges on the entire circumference at the upper and the lower portions is made of stainless steels. Ceramics sheets are appended as necessary to the outer circumferential surface of the bobbin. Then, ceramic electric wires are wound around the outer circumference of the bobbin by a required number of turns to constitute coils. The electric wire is prepared by coating the conductor of nickel-plated copper with ceramic coating material, disposing an insulation material to the outer circumference thereof the further coating the outside with ceramic coating material. This can improve the heat resistance and, since the control rod drives using such heat resistant driving coils can operate at a high temperature. It requires no cooling device and can simplify the reactor and its peripheral structures. (T.M.)

  9. Testing Method for Heat Resistance Under Temperature Gradient

    Science.gov (United States)

    Takagi, K.; Kawasaki, A.; Itoh, Y.; Harada, Y.; Ono, F.

    2007-12-01

    “Testing Method for Heat Resistance under Temperature Gradient” is a Japanese Industrial Standard (JIS) newly established by the Minister of Economy, Trade and Industry, after deliberations by the Japanese Industrial Standards Committee, in accordance with the Industrial Standardization Law. This standard specified the testing method for heat resistance under temperature gradient of materials and coated members of equipment exposed to high temperature, such as aircraft engines, gas turbines, and so on. This paper introduces the principle and overview of the established standard. In addition, taking the heat cycle test using the burner rig for instance, we specifically illustrate the acquirable data and their analysis in the standard. Monitoring of the effective thermal conductivity and acoustic emission particularly enables to the non-destructive evaluation of failure cycle.

  10. Koch–Haaf reaction of adamantanols in an acid-tolerant hastelloy-made microreactor

    Directory of Open Access Journals (Sweden)

    Takahide Fukuyama

    2011-09-01

    Full Text Available The Koch–Haaf reaction of adamantanols was successfully carried out in a microflow system at room temperature. By combining an acid-tolerant hastelloy-made micromixer, a PTFE tube, and a hastelloy-made microextraction unit, a packaged reaction-to-workup system was developed. By means of the present system, the multigram scale synthesis of 1-adamantanecarboxylic acid was achieved in ca. one hour operation.

  11. FINITE ELEMENT ANALYSIS OF HASTELLOY C-22HS IN END MILLING

    OpenAIRE

    Kadirgama, K.; Rahman, M. M.; Ismail, A. R.; Bakar, R. A.

    2011-01-01

    This paper presents a finite element analysis of the stress distribution in the end milling operation of nickel-based superalloy HASTELLOY C-2000. Commercially available finite element software was used to develop the model and analyze the distribution of stress components in the machined surface of HASTELLOY C-22HS following end milling with coated carbide tools. The friction interaction along the tool-chip interface was modeled using the Coulomb friction law. It was found that the stress ha...

  12. Oxidation peculiarities of chromium-nickel alloys for cladding with boron and silicon in water high-temperature-high-pressure steam

    International Nuclear Information System (INIS)

    Studied is the heat resistance of chromium-nickel alloys containing boron and silicon in water high-temperature-high-ressure steam, determined is the composition of corrosion products. It is found that volatility of boron anhydrite promotes the loosening of oxide film and is the main cause of the decreased heat resistance of these alloys. Heat resistance may be increased by changing chemical and phase composition of the alloy, due to the suppression of nickel borides formation in particular

  13. Maleimido substituted cyclotriphosphazene resins for fire and heat resistant composites

    Science.gov (United States)

    Kumar, D.; Fohlen, G. M.; Parker, J. A.

    1983-01-01

    A new class of fire- and heat-resistant matrix resins have been synthesized by the thermal polymerization of maleimido substituted phenoxycyclotriphosphazenes. The resins have exhibited a char yield of 82 percent at 800 C in nitrogen and 81 percent at 700 C in air. Graphite-fabric laminates based on a resin of this class have shown a limiting oxygen index of 100 percent even at 300 C. Details of the fabrication of the resins and the composites and testing procedures are discussed.

  14. Effects of egg yolk and salt on Micrococcaceae heat resistance.

    OpenAIRE

    Verrips, T.; Rhee, R.

    1983-01-01

    The heat resistance and growth possibilities of various members of the Micrococcaceae in egg yolk and egg yolk with added salt were determined. Egg yolk alone protected members of the Micrococcaceae considerably against heat. Whereas in water Staphylococcus aureus S6 had a decimal reduction time (D) value of 66 s at 55 degrees C, its D value in egg yolk at the same temperature was 246 s. In salted egg yolk (water activity, 0.95), S. aureus S6 had a D value of 180 s at 66 degrees C and was lar...

  15. Heat-resistant bacterial phytase in broiler pelleted diets

    Scientific Electronic Library Online (English)

    TC de F, Carlos; LCGS, Barbosa; NN, Shiroma; RL, Dari; G, Baolin; W, Yongcheng; CS da S, Araújo; LF, Araújo.

    2015-03-01

    Full Text Available The objective of the study was to evaluate the effects of a heat-resistant bacterial phytase added to pelleted diets on mineral digestibility, live performance, carcass traits, and bone quality of broilers. Three treatments were evaluated: Positive control; negative control, with 0.10 points reducti [...] on in calcium level and 0.15 points reduction in available phosphorus level; and negative control + phytase at 500 FTU/kg. Mineral digestibility and bone quality results demonstrated that the evaluated phytase resisted pelleting as it increased the utilization of the minerals present in the diet.

  16. Permeation of hydrogen and tritium through heat resistant steels up to 9500C

    International Nuclear Information System (INIS)

    For permeation and diffusion measurements of hydrogen isotopes through heat resistant alloys with bare or oxide coated surface two new methods have been developed. The first works with high-frequency heating of a tabular sample (HF-method), and is used for steady-state hydrogen permeation in the range 700 to 9500C and H2 pressures up to 40 bar. The second method uses two gas loops (TL-method) and a disc-shaped sample in between, and is applicable also for non-steady state (time-lag) measurements. It has been used for tritium permeation between 650 and 9500C at T2 pressures of 10 to 100 ?bar. The HF-method turned out suitable for quick tests of materials behaviour, especially with respect to the overall dependence of permeation on pressure and temperature. The TL-method yields besides permeability also data on diffusivity and solubility. It proved appropriate particularly for investigating the influence of different alloy components, for instance C and Cr content in austenitic steels. With regard to the effect of oxide coatings it seems certain now that restraints of hydrogen dissociation and recombination processes are of stronger importance for the impediment of permeation than presumed so far. (orig.)

  17. Use of Methods of Metallurgy Sprayed and Fast Quenching Powders for Manufacturing Environments Fuel Tubes from Dispersion-Strengthened Oxides (DSO) Heat Resisting Ferritic-Martensitic Steels (P. 1)

    International Nuclear Information System (INIS)

    The technological circuit and optimum modes hardness alloying ferritic-martensitic nanodispersion yttrium oxide is considered. Results of research of structure and physicomechanical properties of the pre-production models made by a method compacting of powders of heat resisting steel EP-450 DSO are resulted. It is shown, that nanostructured steel keeps high enough residual lengthening after cold deformation on 60%

  18. Heat-resistant mechanism of transgenic rape by 45Ca isotope tracer

    International Nuclear Information System (INIS)

    The Ca2+ uptake differences of the rape with heat-resistant gene and the general rape were investigated by 45Ca isotope tracer. The results showed that the rape with heat-resistant gene can strengthen the regulation of calcium absorption. The calcium regulation ability of the heat-resistant genes may be able to play in the rape aspect of the mechanism of resistance. (authors)

  19. Features of abrasive machining of high alloy and high-alloy steels

    International Nuclear Information System (INIS)

    Machinability of steels and alloys of different types by the method of abrasive polishing is considered. Analysis of microstructures, suitable for abrasive polishing was conducted. Recommendations on preparation of a series of steels and alloys for abrasive polishing with the use of corresponding heat treatment are given. The following heat treatment are given. The following materials are among considered ones: stainless steels, corrosion resistant nickel base alloys with molybdenum, heat resistant nickel alloys, magnetically soft alloys, amorphous ferromagnetic alloys, manganese steels and others

  20. Oxidation characteristics of oxide dispersion strengthened (ODS) alloy

    International Nuclear Information System (INIS)

    For the feasibility study of an oxide dispersion strengthened (ODS) alloy to apply to a high temperature structural material in advanced High Temperature Gas-cooled Reactors (HTGRs) and heat utilization systems of HTGR, the oxidation tests of Fe-Cr-Al-Y2O3-based ODS alloy in the simulated HTGR helium environment and the air were carried out together with two kinds of high temperature alloys, i.e., Hastelloy XR and Ni-Cr-W alloys. It was clarified that the ODS alloy had excellent oxidation characteristics in both the environments due to the formation of protective Al-based oxide scale with dispersed Y2O3 on the alloy surface. Furthermore, the comparison between Hastelloy XR and Ni-Cr-W alloys on the oxidation behavior was also discussed. (author)

  1. Characteristics of heat resistance of metal of certain grade

    International Nuclear Information System (INIS)

    Modern development of power machine construction is accompanied by continuous increase of operation parameters and service time of power machine elements. Under the conditions heat resistance characteristics, evaluated by extrapolation for the calculated service time on the basis of restricted duration tests play the decisive role. Pipeline systems (steam supply lines and steam superheaters) are the most metal-consuming elements of modern thermal power plants. Results of the tests are generalized, their statistical processing using the M 220 and ES computers, is realized. According to the method suggested parameters of long-term strength equations for commercial steels are given. Pearlitic, aystenitic and high-chromium steels were considered. 30 comercial series of 12Kh1MF steel were tested by various organizations and the results were processed. Total number of tested samples exceeded 700

  2. Studies Concerning Heat-Resisting Additives for Bitumens

    Directory of Open Access Journals (Sweden)

    Livia Groll

    2008-01-01

    Full Text Available The improvement of causeway’s bitumen adhesiveness is becoming a current practice in our country, especially when is used acid (siliceous aggregate. One of the most important properties of bitumen is its adhesiveness to aggregate, and this property determine the using of bitumen in causeways area. Usually the adhesiveness is defined as the capacity of a binder to cover an aggregate without dispersing itself when touching the water or the traffic aggressions. Therefore, the adhesiveness additives are products that improve the adhesiveness of the bitumen to a certain aggregate. The used additives – ADETEN type (A01 and A03 have a high stocking stability, a low toxicity degree toward the amine, diamine, polyamine-based additives and are liquid products perfectly compatible with all bitumens and easy to use, in comparison to the paste or solid additives, which must be made liquid to be used. But a very important condition, which must be fulfilled by these promoters is the heat-resisting condition.

  3. Behaviour of heat-resistant steels under multistage fatigue stress

    International Nuclear Information System (INIS)

    Four heat-resistant steels (10 CrMo 9 10, 28 CrMoNiV 4 9, X 22 CrMoV 12 1, X 6 CrNiMo 17 13), were used to examine the fatigue under multistage rectangular cyclic stress. The load cycles were made to be similar to the stress affecting power plant components. These are mainly cycles with decreasing and/or increasing stresses, with the temperature or both variables at the same time having been varied in some cases. As characteristical parameters of the modified life-fraction rule, the relative fracture life and for characterizing strains the relative strain life as well were determined. For the assessment of the relative life under any multistage stress, a new step hypothesis, applicable to all possible elementary stress steps, was developed. This hypothesis is able to predict even a consequential effect by means of additional rules. In comparison to this hypothesis, the simple life fraction rule which is unapt for single-stage stress, results in a somehow better prognosis of the fraction time and strain endurance limits under multistage stress. (orig./MM)

  4. Reduction in mechanical anisotropy through high temperature heat treatment of Hastelloy X processed by Selective Laser Melting (SLM)

    Science.gov (United States)

    Etter, T.; Kunze, K.; Geiger, F.; Meidani, H.

    2015-04-01

    Selective Laser Melting (SLM) is an additive manufacturing technology used to directly produce metallic parts from thin powder layers. To evaluate the anisotropic mechanical properties, tensile test specimens of the Ni-base alloy Hastelloy X were built with the loading direction oriented either parallel (z-specimens) or perpendicular to the build-up direction (xy- specimens). Specimens were investigated in the “as-built” condition and after high temperature heat treatment. Tensile tests at room temperature and at 850°C of “as-built” material have shown different mechanical properties for z- and xy-specimens. The anisotropy is reflected in the Young's modulus, with lower values measured parallel to the build-up direction. It is shown that the anisotropy is significantly reduced by a subsequent recrystallization heat treatment. The characterization of microstructural and textural anisotropy was done by Electron Back Scatter Diffraction (EBSD) analysis. Predictions of Young's modulus calculated from the measured textures compare well with the data from tensile tests.

  5. High temperature crevice corrosion of hastelloy x in helium environment containing several kinds of impurities

    International Nuclear Information System (INIS)

    Interaction between a Ni-base heat-resistant alloy and simulated HTR primary coolant environment, which contained controlled concentrations of both oxidizing and carburizing impurities, was examined with emphasis placed on the reactions inside narrow crevice gaps. A test method of providing artificial crevice using a Mo container was developed to obtain quantitative results with resonable reproducibility. The test environment was helium of low oxidizing potential with trace amount of gaseous impurities: H2, H2O, CO2 and CH4. The state of oxidation on the inner surfaces of the crevice was examined by measuring the change in concentration of Cr on the specimen surface using EPMA. Significant difference in the change of the surface was seen along with the distance from the crevice entrance. There was a preferential consumption of oxidizing species in the outer part of the crevice due to the formation of continuous oxide film, leading to porous or discontinuous oxide film formation, and the resultant extensive carburizations in the inner part of the crevice. Vaporization was noted far inside the crevice where oxide film was scarecely formed. The zone of continuous oxide film formation was found to extend into the crevice as a function of the 1/4 power of exposure time, and its reaching distance in a given time was proportional to the square root of opening of crevice gap. These relations were consistent with a model with an assu were consistent with a model with an assumption that the diffusion of reactants through the gas was a rate determining step. The model based on the results obtained will be applied to the crevices with the similar geometrical effects such as the internals of fatigue and creep cracks and also actual crevice formed on the surface of heat exchanger tubes. (author)

  6. FY 1998 annual report on the study on solidification process of hot, heat-resistant metal melts; 1998 nendo tainetsu kinzoku koon yueki no gyoko katei no kenkyu chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    Described herein are results of the studies on basic aspects of solidification process of hot, heat-resistant metal melts under a microgravity atmosphere, its applicability to industrial purposes, production of new metallic structures by precision casting and supercooling solidification of the heat-resistant, metal alloy parts, and evaluation techniques therefor. In the supercooling solidification of Al, its purity greatly determines the crystal morphology. The single crystal can be produced under a microgravity when it is 99.9% pure. The supercooling solidification under a microgravity can give an Al-Pb alloy structure of uniform dendrite structure both on the surface and inside, free of gravity-caused segregation of Pb. The welding problems caused by Al{sub 2}O{sub 3} present in the Al are solved. The study also clarifies the effects of the microgravity atmosphere in the spot welding by a pulsed YAG laser on, e.g., melting characteristics, welding phenomena and formation of welding defects. The basic knowledge obtained is expected to contribute to, e.g., precision casting and welding of heat-resistant alloys, and creation of new alloys. (NEDO)

  7. Cold Shock Response in Sporulating Bacillus subtilis and Its Effect on Spore Heat Resistance

    OpenAIRE

    Movahedi, Sara; Waites, William

    2002-01-01

    Cold shock and ethanol and puromycin stress responses in sporulating Bacillus subtilis cells have been investigated. We show that a total of 13 proteins are strongly induced after a short cold shock treatment of sporulating cells. The cold shock pretreatment affected the heat resistance of the spores formed subsequently, with spores heat killed at 85 or 90°C being more heat resistant than the control spores while they were more heat sensitive than controls that were heat treated at 95 or 100...

  8. Trends in the development of heat resistant steels for seamless tubes in power station construction

    International Nuclear Information System (INIS)

    The requirements for heat resistant steels for power station construction have changed. Good properties in relation to resistance to heat are taken for granted; today the key points of interest are ductility at low temperatures and weldability requirements. The erratic increases in the price of fossil fuels lead to increase in steam temperature and pressure just as the construction of advanced reactors automatically leads to the use of heat-resistant austenitic steels. (orig.)

  9. Long term creep behavior of Incoloy 800H and Hastelloy X in simulated HTGR environments

    International Nuclear Information System (INIS)

    Creep rupture tests on Incoloy 800H and Hastelloy X had been carried out in simulated steam-cycle HTGR helium environments for two levels of moisture. The wet helium studies have been completed for a maximum test time of 16,000 hours; the dry helium tests are still in progress with a maximum test time of 18,000 hours. Standard air tests have been running for over 35,000 hours. The creep rupture behavior of Incoloy 800H in the wet helium is not significantly different from that in air but the dry helium increases the rupture life. Hastelloy X shows a slightly lower rupture life in the wet helium while the dry helium improves the creep properties in comparison with standard air tests. Oxidation is the major gas-metal interaction in both helium environments

  10. Oxidation kinetics and oxidation mechanism in tungsten-vanadium alloys

    International Nuclear Information System (INIS)

    The method of continuous weighing has been used to investigate oxidation of tungsten alloys with 1-20 weight% V at 900-1300 deg C in the air. It is shown that oxidability of alloys containing 1% V noticeably decreases as compared with tungsten. Alloys with 1-10% V have higher heat resistance as compared with tungsten but positive effect of vanadium decreases with an increase of alloying degree and at 20% vanadium content the alloying effect completely disappears

  11. Influencia de los parámetros de soldeo fuerte en la microestructura y propiedades mecánicas de la unión de la aleación base níquel Hastelloy B2

    Directory of Open Access Journals (Sweden)

    Sotelo, José Carlos

    2014-09-01

    Full Text Available A study of the high vacuum brazing process of solid solution strengthened Hastelloy B2 nickel alloy has been done. A first stage of research has focused on the selection of the most appropriate brazing filler metal to the base material and vacuum furnace brazing process. The influence of welding parameters on joint microstructure constituents, relating the microstructure of the joint to its mechanical properties, has been evaluated. Two gaps of 50 and 200 micrometers, and two dwell times at brazing temperature of 10 and 90 minutes were studied. The braze joint mainly consists of the nickel rich matrix, nickel silicide and ternary compounds. Finally, the results of this study have shown the high bond strength for small gaps and increased dwell times of 90 minutes.Se realizó un estudio pormenorizado del proceso de soldeo fuerte en horno de alto vacío de la aleación base níquel Hastelloy B2 fortalecida por solución sólida. En una primera fase del trabajo se seleccionó el material de aporte acorde al material objeto de unión y a la fuente de calentamiento seleccionada. Posteriormente, se evaluó la influencia del gap (50 y 200 micrómetros y tiempo de permanencia a temperatura de soldeo (10 y 90 minutos sobre los microconstituyentes de la unión, relacionando la microestructura con las propiedades mecánicas de la junta. Los análisis metalográficos mostraron una unión constituida por una matriz rica en níquel, siliciuros de níquel y compuestos ternarios. Finalmente, los resultados de los ensayos mecánicos a esfuerzos cortantes mostraron una elevada resistencia para gaps de 50 micrómetros y tiempos de permanencia de 90 minutos.

  12. Physical Simulation of Friction Stir Welding and Processing of Nickel-Base Alloys Using Hot Torsion

    Science.gov (United States)

    Rule, James R.; Lippold, John C.

    2013-08-01

    The Gleeble hot torsion test was utilized in an attempt to simulate the friction stir-processed microstructure of three Ni-base alloys: Hastelloy X, Alloy 625, and Alloy 718. The simulation temperatures were based on actual thermal cycles measured by embedded thermocouples during friction stir processing of these alloys. Peak process temperatures were determined to be approximately 1423 K (1150 °C) for Hastelloy X and Alloy 625 K and 1373 K (352 °C and 1100 °C) for Alloy 718. The peak temperature and cooling rates were programed into the Gleeble™ 3800 thermo-mechanical simulator to reproduce the stir zone and thermo-mechanically affected zone (TMAZ) microstructures. The TMAZ was successfully simulated using this technique, but the stir zone microstructure could not be accurately reproduced, with hot torsion samples exhibiting larger grain size than actual friction stir processing trials. Shear stress and strain rates as a function of temperature were determined for each material using hot torsion simulation.

  13. Electrochemical Impedance Spectroscopy Of Metal Alloys

    Science.gov (United States)

    Macdowell, L. G.; Calle, L. M.

    1993-01-01

    Report describes use of electrochemical impedance spectroscopy (EIS) to investigate resistances of 19 alloys to corrosion under conditions similar to those of corrosive, chloride-laden seaside environment of Space Transportation System launch site. Alloys investigated: Hastelloy C-4, C-22, C-276, and B-2; Inconel(R) 600, 625, and 825; Inco(R) G-3; Monel 400; Zirconium 702; Stainless Steel 304L, 304LN, 316L, 317L, and 904L; 20Cb-3; 7Mo+N; ES2205; and Ferralium 255. Results suggest electrochemical impedance spectroscopy used to predict corrosion performances of metal alloys.

  14. Development of heat-resistant FBG sensor for high temperature structures monitoring

    International Nuclear Information System (INIS)

    Strain sensors, which can be used for integrity monitoring of plant components and piping during the operation period continuously, are effective from the point of view of proactive maintenance. FBG (Fiber Bragg Grating) sensor is one of the expective sensors and is used in various plants and civil engineering and construction fields except for high temperature service. In order to apply to the component and piping of fast reactor, heat resistance is an indispensable feature of the sensor. In this study, we tried to improve heat resistance of FBG by using femtosecond laser in the process. The heat resistance at the FBGs was examined experimentally and the results compared with those of ordinary FBGs. (author)

  15. Investigation on corrosion behavior of Ni-based alloys in molten fluoride salt using synchrotron radiation techniques

    International Nuclear Information System (INIS)

    Ni-based alloys have been selected as the structural materials in molten-salt reactors due to their high corrosion resistance and excellent mechanical properties. In this paper, the corrosion behavior of some Ni-based superalloys including Inconel 600, Hastelloy X and Hastelloy C-276 were investigated in molten fluoride salts at 750 °C. Morphology and microstructure of corroded samples were analyzed using scanning electron microscope (SEM), synchrotron radiation X-ray microbeam fluorescence (?-XRF) and synchrotron radiation X-ray diffraction (SR-XRD) techniques. Results from ?-XRF and SR-XRD show that the main depleted alloying element of Ni-based alloys in molten fluoride salt is Cr. In addition, the results indicate that Mo can enhance the corrosion resistance in molten FLiNaK salts. Among the above three Ni-based alloys, Hastelloy C-276 exhibits the best corrosion resistance in molten fluoride salts 750 °C. Higher-content Mo and lower-content Cr in Hastelloy C-276 alloy were responsible for the better anti-corrosive performance, compared to the other two alloys

  16. Structure optimization and damage behaviour of heat-resistant CrMoV-steels

    International Nuclear Information System (INIS)

    The object of the investigations was to optimize the heat treatment conditions of steel 12 CrMoV 4 3 (around 0,12% C; 1% Cr; 0,3% Mo; 0,25% V) on the basis of known structure-property relations of heat resistant steel-CrMoV in such way that the performance of this steel relating to its long-term heat resistance is completely utilized. Further, the influence of heat treatment or of the initial structure was analyzed as well as of further factors on the evolution of damages by formation of pores due to creep. (orig.)

  17. Hastelloy-X for high-temperature gas-cooled reactor applications

    International Nuclear Information System (INIS)

    Hastelloy-X is a potential structural material for use in gas-cooled reactor systems. In this application, data are necessary on the mechanical properties of base metal and weldments under realistic service conditions. The test environment studied was helium that contained small amounts of H2, CH4, and CO. This environment was found to be carburizing, with the kinetics of this process becoming rapid above 8000C. Suitable weldments of Hastelloy-X were prepared by several processes; those weldments generally had the same properties as base metal except for lower fracture strains under some conditions. Some samples were aged for up to 20 000 h in the test gas and tested, and some creep tests on as-received material exceeded 40 000 h. The predominant effects of aging were the significant reduction in the fracture strains at ambient temperature and the lower strains for samples aged in high-temperature gas-cooled reactor (HTGR) helium than for those aged in inert gas. Under some conditions, aging also resulted in increased yield and ultimate tensile strength. Creep tests failed to show the effects of environment, aging, or welding on the creep strength of Hastelloy-X; however, the fracture strains for weldments were generally lower than they were for base metal. Prior aging in inert gas for 20 000 h at 538 and 8710C reduced the fatigue life slightly, but no difference was observed in the fatigue properties of samples aged in air fatigue properties of samples aged in air and HTGR helium environments

  18. Corrosion tests of 316L and Hastelloy C-22 in simulated tank waste solutions

    International Nuclear Information System (INIS)

    Both the 316L stainless steel and Hastelloy C-22 gave satisfactory corrosion performance in the simulated test environments. They were subjected to 100 day weight loss corrosion tests and electrochemical potentiodynamic evaluation. This activity supports confirmation of the design basis for the materials of construction of process vessels and equipment used to handle the feed to the LAW-melter evaporator. BNFL process and mechanical engineering will use the information derived from this task to select material of construction for process vessels and equipment

  19. Transformation processes during annealing of Al-amorphous alloys

    OpenAIRE

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

    1993-01-01

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

  20. Evaluation of candidate alloys for the construction of metal flex hoses in the STS launch environment

    Science.gov (United States)

    Ontiveros, Cordelia

    1988-01-01

    Various vacuum jacketed cryogenic supply lines at the Shuttle launch site use convoluted flexible expansion joints. The atmosphere at the launch site has a very high salt content, and during a launch, fuel combustion products include hydrochloric acid. This extremely corrosive environment has caused pitting corrosion failure in the flex hoses, which were made of 304L stainless steel. A search was done to find a more corrosion resistant replacement material. This study focused on 19 metal alloys. Tests which were performed include electrochemical corrosion testing, accelerated corrosion testing in a salt fog chamber, long term exposure at the beach corrosion testing site, and pitting corrosion tests in ferric chloride solution. Based on the results of these tests, the most corrosion resistant alloys were found to be (in order) Hastelloy C-22, Inconel 625, Hastelloy C-276, Hastelloy C-4, and Inco Alloy G-3. Of these top five alloys, the Hastelloy C-22 stands out as being the best of those tested for this application.

  1. Microstructural stability of 9-12%Cr ferrite/martensite heat-resistant steels

    Science.gov (United States)

    Yan, Wei; Wang, Wei; Shan, Yi-Yin; Yang, Ke

    2013-03-01

    The microstructural evolutions of advanced 9-12%Cr ferrite/martensite heat-resistant steels used for power generation plants are reviewed in this article. Despite of the small differences in chemical compositions, the steels share the same microstructure of the as-tempered martensite. It is the thermal stability of the initial microstructure that matters the creep behavior of these heat-resistant steels. The microstructural evolutions involved in 9-12%Cr ferrite heat-resistant steels are elaborated, including (1) martensitic lath widening, (2) disappearance of prior austenite grain boundary, (32) emergence of subgrains, (4) coarsening of precipitates, and (5) formation of new precipitates, such as Laves-phase and Z-phase. The former three microstructural evolutions could be retarded by properly disposing the latter two. Namely improving the stability of precipitates and optimizing their size distribution can effectively exert the beneficial influence of precipitates on microstructures. In this sense, the microstructural stability of the tempered martensite is in fact the stability of precipitates during the creep. Many attempts have been carried out to improve the microstructural stability of 9-12%Cr steels and several promising heat-resistant steels have been developed.

  2. Broadening of temperature range when testing heat-resistant alloys for high-temperature chloride corrosion

    International Nuclear Information System (INIS)

    Results of corrosion resistance of materials with nickel, iron and chromium base (EhK-9VD, Kh18N10T and VKh-2K) in sodium chloride, equimolar mixture of sodium and potassium chlorides and internary eutectics (48.7 % of MgCl2 + 38.2 % of KCl+13.1 % of NaCl) at 400-900 deg C temperature and 20 hour exposure are presented. it is shown that application of ternary mixture instead of sodium chloride and binary chloride mixture indicated allows one to reduce the temperature of testing for chloride corrosion resistance down to 410 deg C, and thus to broaden the testing temperature range by 250-400 deg C

  3. Effect of structural instability and oxidation on heat resisting alloy endurance at high temperatures

    International Nuclear Information System (INIS)

    A joint effect of structural state and oxidation specified by a preliminary isothermal exposition on fatigue resistance of the nickel superalloy under conditions of the pure bending with rotation is studied. An increase of the limited fatigue ranges due to the ageing at the moderate temperatures (to 0.6 Tsub(melt)) and their decrease during ageing under conditions of higher temperatures are established. Oxidation of the surface exerts a noticeable action on the fatigue damage at high amplitudes of the variable stresses. At the low values of amplitudes their fatigue is mainly determined by the structural state of the material

  4. Radiation embrittlement and swelling of austenitic alloys in different structural state

    International Nuclear Information System (INIS)

    Reviewed are the investigations of the heat-resistance and swelling of the chrome-nickel austenite steels and alloys. Pointed out is the importance of the early stages of decay in solid solutions and also the influence of the iniformity of the secondary phase precipitation in the grains on the heat-resistance criteria and opposition to the radiation swelling of alloys. It is shown that through alloying swelling may be suppressed and the influence of the neutron impact on the deformation ability of high-nickel austenite steels and alloys reduced considerably

  5. Fundamental studies on electron beam welding on heat-resistant superalloys for nuclear plants, (3)

    International Nuclear Information System (INIS)

    In this report, microcracks in the electron beam welds of the superalloys for nuclear plants were metallurgically investigated. Obtained conclusions can be summarized as follows; 1) The precipitates adjacent to the fusion line of Hastelloy X, Inconel 617 and Incoloy 807 which accompany microcracks change and melt clearly. On the other hand, those of Inconel 625 and SUS 316 in which microcracks never occur remain unchanged, and the precipitates remain nearly in the original condition in the case of Incoloy 800 which accompanies microcracks. 2) Main precipitates identified for every superalloy are M23C6 and M6C for Hastelloy X, M6C for Inconel 617, NbC and Ti(C,N) for Incoloy 807, NbC for Inconel 625, Ti(C,N) for Incoloy 800 and M23C6 for SUS 316. 3) The liquation of precipitates is considered to take place only when either melting temperature of precipitates or eutectic temperature between precipitates and matrix ? is lower than the temperature of matrix to start melting. 4) It is easily presumed that a microcrack will initiate at the melted precipitate at the grain boundary of the heat affected zone adjacent to the fusion line where the distribution of temperature, stress and strain is of peculiar characteristics. This distribution will be described in the following report in details. (author)

  6. Corrosion resistant alloy uses in the power industry

    International Nuclear Information System (INIS)

    Nickel-base alloys have been used as cost-effective measures in a variety of severely corrosive situations in pollution control units for coal-fired power plants. Cost effectiveness and practical answers to corrosion problems are illustrated (specifically the wallpaper concept/metallic lining technique). Numerous cases of successful use of HASTELLOY alloys in Flue Gas Desulfurization (FGD) systems and hazardous waste treatment incineration scrubber systems are listed. In this paper developments in nickel-base alloys and their use in FGD and other segments of the power industry are discussed. In the Ni-Cr-Mo-W alloy family, the C-22 alloy has the best resistance to localized corrosion in halide environments (chloride/fluoride-containing solutions). This alloy is also used effectively as a universal filler metal to weld less-resistant alloys were weld corrosion may be a problem. Field performance of this alloy in the power industry is described

  7. ?????? ??? Alloy ?????? ? ???????? ???????? ?? ??????? ???? ???? ???? ????? ?? ?????? ????????

    Directory of Open Access Journals (Sweden)

    Nikzad Sakineh

    2015-05-01

    Full Text Available Background and Aims: The nice clinical results with high strength dental ceramics such as zirconia make clinicians to use them more vigorously. Despite of excellent strength, live color and outstanding biocompatibility, zirconia ceramics showed low bonding capability, which makes them difficult to bond to resin cements and tooth structures. This study compared the effects of two different priming agents on the shear bond strength of zirconia to dentin structure.   Materials and Methods: 80 molar teeth were occlusally reduced ? 3mm and bonded to 80 zirconia specimens, which were prepared according to company instructions. All specimens were then divided into 4 groups (20 specimens in each group. Group A remained as control and group B, C and D were prepared as below: primed with Bisco, Ivoclar, and Alloy primer. These groups also were sandblasted. The treated specimens were then cemented to corresponding tooth followed by an incubation period of 24 hours in 370C. The specimens were all loaded to fracture by a universal testing machine. Data were analyzed using 2-way kolmogorov-Smirnov test andKruskal-Wallis.   Results: The mean shear bond strength of the 4 groups tested were 5.93 ± 2.04Mpa, 11.45 ± 4.39Mpa,14.34 ± 4.41Mpa and 11.14 ± 4.84Mpa, respectively. As a result, the mean shear bond strength in groups B, C and D was significantly higher than control and the highest value corresponded to the C group (P<0.05.   Conclusion: Under the limitation of this in vitro study, it can be concluded that the combination method of sandblast with the use of primer Bisco, Ivoclar and Alloy primer can increase the shear bond strength of zirconia.

  8. Thermomechanical cyclic hardening behavior of Hastelloy-X. M.S. Thesis

    Science.gov (United States)

    Bartolotta, P. A.

    1985-01-01

    Experimental evidence of thermomechanical history dependence on the cyclic hardening behavior of a representative combustor liner material Hastelloy-X is presented, along with a discussion about the relevant concept of thermomechanical path dependence. Based on the experimental results, a discussion is given on the inadequacy of formulating nonisothermal constitutive equations solely on the basis of isothermal testing. Finally, the essence of a mathematical representation of thermoviscoplasticity is presented that qualitatively accounts for the observed hereditary behavior. This is achieved by formulating the scaler evolutionary equation in an established viscoplastic theory to reflect thermomechanical path dependence. Although the necessary nonisothermal tests for further quantifying the thermoviscoplastic model have been identified, such data are not yet available.

  9. Effect of grain size and cold working on high temperature strength of Hastelloy X

    International Nuclear Information System (INIS)

    Effect of grain size and cold working on creep, creep rupture, low cycle fatigue and tensile strengths of Hastelloy X were studied at temperatures ranging from 800 to 10000C. In order to apply these data to design, the allowable design stresses were estimated by expanding the criteria of ASME Code Case 1592 to such a high temperature range. The allowable design stress increased, on the other hand, the low cycle fatigue life decreased with increasing grain size. Cold working up to a ratio of 5 per cent may not be a serious problem in design, because the allowable design stress and the fatigue life were little affected. The cause of these variations in strength was discussed by examining the initiation and growth of cracks, and the microstructures. (author)

  10. Synthesis of heat-resistant SiC fiber by radiation processing

    International Nuclear Information System (INIS)

    The heat-resistant silicon carbide (SiC) fiber was formed from the precursor fiber of silicon containing organic polymer 'polycarbosilane (PCS)' by radiation curing technique. PCS fibers were irradiated in He atmosphere by 2MeV electron beam, then the fiber changed to non-melt fibers during the heat treatment for conversion from PCS fiber to SiC fiber. The SiC fibers, which contained less oxygen by the radiation curing of PCS fiber, showed high heat-resistance. The tensile strength and Young's modulus of SiC fiber containing oxygen of 0.4 % was 2.5 GPa and 280 GPa, respectively, after heat treatment at 1973 K (1700C) in Ar atmosphere, which is higher by 500 K than those of SiC fiber as 'Nicalon' which was formed from thermal oxidation curing of PCS fiber. (author)

  11. Injection Molded Optical Lens Using a Heat Resistant Thermoplastic Resin with Electron Beam Cross-Linking

    Science.gov (United States)

    Tomomi Sano,; Yoshitomo Iyoda,; Takayuki Shimazu,; Michiko Harumoto,; Akira Inoue,; Makoto Nakabayashi,; Hiroshi Ito,

    2010-05-01

    The poor heat resistant properties of a transparent thermoplastic resin was improved by electron beam irradiation cross-linking. A correcting aspheric lens for a 635-nm laser diode was fabricated using an injection molding machine, and was irradiated with an electron beam. The near field pattern (NFP), the far field pattern (FFP) at the focus position and the transmittance of the lens did not change after exposure to a 260 °C reflow process for 60 s.

  12. Estimating the Condition of the Heat Resistant Lining in an Electrical Reduction Furnace

    OpenAIRE

    Waalmann, Jan G.

    1988-01-01

    This paper presents a system for estimating the condition of the heat resistant lining in an electrical reduction furnace for ferrosilicon. The system uses temperature measured with thermocouples placed on the outside of the furnace-pot. These measurements are used together with a mathematical model of the temperature distribution in the lining in a recursive least squares algorithm to estimate the position of 'the transformation front'. The system is part of a monitoring system which is bein...

  13. Experimental determination of contact heat resistance between uranium dioxide and cladding

    International Nuclear Information System (INIS)

    The objective of this work was studying thermal contact resistance between fuel and cladding under different conditions similar to reactor operating conditions in order to avoid overheating that could cause damage. According to experimental data, variation of contact heat resistance was analyzed dependent on the neutron flux. Using calculated values of fuel pellets radial expansion, dependence of heat contact resistance is given as a function of gap dimensions at constant temperature

  14. Changes of the permeability of hydrogen of heat resisting metallic materials caused by thin oxide barriers on the surface

    International Nuclear Information System (INIS)

    The permeability of hydrogen and tritium through oxide surface layers of Incoloy 800, Incoloy 800H, Incoloy 802, Incoloy 807, IN 586, Inconel 617, Hastelloy X, HK 40, Manaurite 36X, IN 519, IN 638 and IN 643 was studied dependent on temperature (600-10000C) and hydrogen pressure (1-20 bar). (TWO)

  15. Novel strains of Moorella thermoacetica form unusually heat-resistant spores.

    Science.gov (United States)

    Byrer, D E; Rainey, F A; Wiegel, J

    2000-11-01

    Two strains of Moorella thermoacetica, JW/B-2 and JW/DB-4, isolated as contaminants from autoclaved media for chemolithoautotrophic growth containing 0.1% (wt/vol) yeast extract, formed unusually heat-resistant spores. Spores of the two strains required heat activation at 100 degrees C of more than 2 min and up to 90 min for maximal percentage of germination. Kinetic analysis indicated the presence of two distinct subpopulations of heat-resistant spores. The decimal reduction time (D10-time=time of exposure to reduce viable spore counts by 90%) at 121 degrees C was determined for each strain using spores obtained under different conditions. For strains JW/DB-2 and JW/ DB-4, respectively, spores obtained at approximately 25 degrees C from cells grown chemolithoautotrophically had D10-times of 43 min and 23 min; spores obtained at 60 degrees C from cells grown chemoorganoheterotrophically had D10-times of 44 min and 38 min; spores obtained at 60 degrees C from cells grown chemolithoautotrophically had D10-times of 83 min and 111 min. The thickness of the cortex varied between 0.10 and 0.29 microm and the radius of the cytoplasm from 0.14 to 0.46 microm. These spores are amongst the most heat-resistant noted to date. Electron microscopy revealed structures within the exosporia of spores prior to full maturity that were assumed to be layers of the outer spore coat. PMID:11131023

  16. Significant effect of Ca2+ on improving the heat resistance of lactic acid bacteria.

    Science.gov (United States)

    Huang, Song; Chen, Xiao Dong

    2013-07-01

    The heat resistance of lactic acid bacteria (LAB) has been extensively investigated due to its highly practical significance. Reconstituted skim milk (RSM) has been found to be one of the most effective protectant wall materials for microencapsulating microorganisms during convective drying, such as spray drying. In addition to proteins and carbohydrate, RSM is rich in calcium. It is not clear which component is critical in the RSM protection mechanism. This study investigated the independent effect of calcium. Ca(2+) was added to lactose solution to examine its influence on the heat resistance of Lactobacillus rhamnosus ZY, Lactobacillus casei Zhang, Lactobacillus plantarum P8 and Streptococcus thermophilus ND03. The results showed that certain Ca(2+) concentrations enhanced the heat resistance of the LAB strains to different extents, that is produced higher survival and shorter regrowth lag times of the bacterial cells. In some cases, the improvements were dramatic. More scientifically insightful and more intensive instrumental study of the Ca(2+) behavior around and in the cells should be carried out in the near future. In the meantime, this work may lead to the development of more cost-effective wall materials with Ca(2+) added as a prime factor. PMID:23617813

  17. Evaluation of the strain variability of Salmonella enterica acid and heat resistance.

    Science.gov (United States)

    Lianou, Alexandra; Koutsoumanis, Konstantinos P

    2013-06-01

    The inherent acid and heat resistances of 60 Salmonella enterica strains were assessed in tryptone soy broth without dextrose acidified to pH 3.0 or heated at 57 °C. A total of 360 inactivation curves were generated. Regarding the acid challenge experiments, the inactivation rate (kacid), estimated using the log-linear model, ranged from 0.47 to 3.25 h(-1). A log-linear model with a "survival tail" was used to describe the thermal inactivation of the strains, and the estimated inactivation rate (kheat) ranged from 0.42 to 1.33 min(-1). The strain variability of kacid was considerably higher than that of kheat with the coefficient of variation of this kinetic parameter among the tested strains being 39.0% and 18.3%, respectively. No correlation was observed between the estimated kacid and kheat values of the 60 S. enterica strains. Furthermore, no trends among the tested strains related to origin, serotype or antibiotic resistance profile were evident. The present study is the first one to comparatively evaluate the inherent acid and heat resistance profiles of multiple S. enterica strains. Beyond their value in strain selection for use in food safety challenge studies, the collected data should be useful in describing and integrating the strain variability of S. enterica acid and heat resistance profiles in quantitative microbial risk assessment. PMID:23541192

  18. Process of brazing using low temperature braze alloy of gold-indium tin

    International Nuclear Information System (INIS)

    A heat resistant brazing alloy of a major amount of gold, a lesser amount of indium and a minor amount of tin. The alloy is particularly suited for use in bonding electrical components to chip carrying substrates which are to be reworked

  19. Analysis of thermal fatigue properties by Barkhausen noise effect on E911 heat-resistance steel

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Dong Ho; Nam, Soo Woo [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2005-11-15

    In the present research work, it was studied whether magnetic approaches can be used for the life prediction evaluation and defect measurement in heat-resistance E911 ferritic steel. Destructive and non-destructive test methods were used. Transmission electron microscopy, coercivity measurements and Barkhausen-Noise(BN) measurements were also used. This research aims to clarify the dependency how the thermal fatigue process influences the magnetic properties of E911 steel, which are often used in european power plant applications. It is also attempted to investigate, whether the BN measurement can be applied to monitor the microstructural changes caused by thermal fatigue of the E911 ferritic steel.

  20. A study on application of rare earth metals in heat resistant steels

    International Nuclear Information System (INIS)

    The influence of rare earth (RE) on the oxidation, high temperature strength and hot-ductility of Cr-Si, Cr-Ni and Cr-Ni -N steels has been studied in order to tap the potentialities of RE in heat resistant steels. Experimental steels were melted in an induction furnace. The amount of metallic La or Ce additions were controlled in the range of 0.01-0.10%. In order to keep nearly the same basic composition of the steel, every heat was poured into two ingots, one with RE, another without

  1. Heat resistance and local structure of FeCl2-absorbed crosslinked poly(?-glutamic acid)

    International Nuclear Information System (INIS)

    Fiber of Japanese food natto (Bacillus subtilis) is known to be superabsorbent poly(?-glutamic acid) (PGA). NaCl particles precipitate in FeCl2-absorbed crosslinked PGA when heated at crystallization temperature of 320 deg C for 10 to 60 min. After heat treatment the Moessbauer spectrum of FeCl2-crosslinked PGA consists of a quadrupole doublet due to FeCl2 x 2H2O. The Moessbauer spectrum of anhydrous FeCl2 reagent heated under the same condition shows an intense sextet due to ?-Fe2O3. These results prove that the superabsorbent polymer, crosslinked PGA, has higher heat resistance. (author)

  2. Kinetics and mechanisms of crack propagation under creep in heat resisting steel

    International Nuclear Information System (INIS)

    Distribution of creep cracks is studied for rotor heat resisting steel within the temperature range of 460...560 deg C and test duration up to 3000 h. A considerable growth of cracks for 1000 h is observed with the values of stress intensity factors 3-7 times lower than the Ksub(Ic) value. Intergranular fracture is observed with comparatively high values of Ksub(I), crack growth being of a discontinuous character; with comparatively small value of Ksub(I) the crack growth occurs due to the growth of pores, their coalescence and convergence with the crack tip

  3. Studies of thermal-cycle endurance of heat resistant materials under asymmetric thermomechanical loading

    International Nuclear Information System (INIS)

    Results of experimental investigation of thermal-cycle endurance of heat resistant materials under conditions of asymmetric thermo-mechanical loading are presented. Using the maximum-likelyhood fit statistical evaluation of the parameters of logarithmically normal distribution of the sample endurance are obtained with an account of the parameter dependence on the level of stresses. A mathematical model of endurance based on the approximation of diagrams of limiting stresses in the case of asymmetric thermo-mechanical loading with the equation of inclined ellipse is suggested. Comparison of the calculated endurance, obtained with an aid of the model with the experiment results is made

  4. Microstructural evolution during creep deformation of an 11CrMoVNb ferritic heat resistant steel

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyu-Ho; Park, Dae-Bum [Korea Institute of Science and Technology, Seoul (Korea, Republic of). Materials and Devices Div.; Korea Univ., Seoul (Korea, Republic of). Dept. of Materials Science; Kwun, S.I. [Korea Univ., Seoul (Korea, Republic of). Dept. of Materials Science; Suh, Jin-Yoo; Jung, Woo-Sang [Korea Institute of Science and Technology, Seoul (Korea, Republic of). Materials and Devices Div.

    2010-07-01

    The effect of creep deformation on the microstructural development of an 11CrMoVNb ferritic heat resistant steel during high temperature creep test is investigated. Coarsening behavior of the precipitates, M{sub 23}C{sub 6} and MX, and growth behavior of martensite laths of crept specimens are carefully observed from both gage and grip parts of the specimens in order to discuss the effect of deformation. Particle coarsening and martensite lath widening are pronounced in the gage part due to the creep deformation. (orig.)

  5. Obtaining Hardened Layers of Heat-Resistant Steels by Plasma-Welding Deposition of Congeneric Materials

    Directory of Open Access Journals (Sweden)

    Yuri Dmitrievich Shitsyn

    2015-02-01

    Full Text Available The paper presents the research results on plasma-hardening of heat-resistant steel layers by plasma-welding deposition of congeneric materials under straight and reverse polarity current. The dependence of the deposited layer quality on the current polarity has been determined. A metallographic examination and measurement of micro-hardness of the deposited layer have been conducted. The dependence of the deposited layer characteristics on the welding parameters has been determined. The obtained results allow the use of plasma-welding deposition to obtain layers with the required strength characteristics using the material, congeneric to the parent material.

  6. Comparison of strength characteristics of heat resisting materials under active tension and constant load

    International Nuclear Information System (INIS)

    Strength characteristics of heat resisting materials (steel 12Kh1MF) obtained during short-term active tension with constant deformation rate are shown to be used for plotting curves of a long-term strength on small temporal basis. For this purpose a graph was suggested to be marked with the points whose coordinates corresponded to a value of a spontaneously measured active deformation time to failure of a sample with the respective equivalent strains determined from deformation curves by a calculation method

  7. Study on new concept for an LMFBR lining system using heat resistant and sodium compatible concrete

    International Nuclear Information System (INIS)

    A new concept of an LMFBR lining system using heat resistant and sodium compatible concrete has been developed. The objective was to reduce the cost and construction period for the conventional steel lining system used to protect the secondary building's floor concrete from leaked sodium. Screening tests and small-scale liner model tests have been carried out to select a material candidate for two kinds of lining system. The sodium pouring test with medium-scale lining floor model was carried out to evaluate the structure integrity. A hydrogen generation test from concrete was accomplished to predict the sodium leakage consequences analytically. (author)

  8. Estimation of work capacity of welded mounting joints of pipelines of heat resisting steel

    International Nuclear Information System (INIS)

    The analysis of a work capacity of circular welds made for the Dsub(y)850 pipeline connection with high pressure vessels of heat resisting steel of the 15Kh1NMFA type has been carried out on the base of test results with small samples and real units. Welds were performed using the manual electric arc welding without the following heat treatment. It has been shown that residual stresses in such welds do not produce an essential effect on the resistance of weld metal and heat affected zone on the formation and developments of cracks

  9. Materials for Advanced Turbine Engines (MATE): Project 3: Design, fabrication and evaluation of an oxide dispersion strengthened sheet alloy combustor liner, volume 1

    Science.gov (United States)

    Henricks, R. J.; Sheffler, K. D.

    1984-01-01

    The suitability of wrought oxide dispersion strengthened (ODS) superalloy sheet for gas turbine engine combustor applications was evaluated. Incoloy MA 956 (FeCrAl base) and Haynes Developmental Alloy (HDA) 8077 (NiCrAl base) were evaluated. Preliminary tests showed both alloys to be potentially viable combustor materials, with neither alloy exhibiting a significant advantage over the other. Both alloys demonstrated a +167C (300 F) advantage of creep and oxidation resistance with no improvement in thermal fatigue capability compared to a current generation combustor alloy (Hastelloy X). MA956 alloy was selected for further demonstration because it exhibited better manufacturing reproducibility than HDA8077. Additional property tests were conducted on MA956. To accommodate the limited thermal fatigue capability of ODS alloys, two segmented, mechanically attached, low strain ODS combustor design concepts having predicted fatigue lives or = 10,000 engine cycles were identified. One of these was a relatively conventional louvered geometry, while the other involved a transpiration cooled configuration. A series of 10,000 cycle combustor rig tests on subscale MA956 and Hastelloy X combustor components showed no cracking, thereby confirming the beneficial effect of the segmented design on thermal fatigue capability. These tests also confirmed the superior oxidation and thermal distortion resistance of the ODS alloy. A hybrid PW2037 inner burner liner containing MA956 and Hastelloy X components was designed and constructed.

  10. The heat resistance of a polyurethane coating filled with modified nano-CaCO3

    Science.gov (United States)

    Li, Bin; Li, Song-Mei; Liu, Jian-Hua; Yu, Mei

    2014-10-01

    The modification of polyurethane coating by adding surface-modified CaCO3 nanoparticles (nano-CaCO3) was investigated in this paper. To improve interfacial interaction between the nano-CaCO3 and the polyurethane (PU) matrix, a silane coupling agent (KH560) was used to modify the nano-CaCO3. The grafting of KH560 on the nano-CaCO3 surfaces was characterized by the TEM, FTIR and TGA techniques. The modification of the nano-CaCO3 surfaces with KH560 was demonstrated to improve the dispersity of nano-CaCO3. FTIR, SEM and AFM were used to characterize the polyurethane coating. The FTIR spectrum indicated that the modification of nano-CaCO3 does not influence the chemical structure of the PU matrix. The roughness and gloss of the nanocomposite coatings containing various amount of nano-CaCO3 were evaluated using a roughness tester and a brightness meter. The heat resistance of the polyurethane coating containing various amounts of nano-CaCO3 was evaluated using the TGA technique. The results revealed that nano-CaCO3 treatment with KH560 improves the nanoparticle dispersion and heat-resistance of polyurethane coating.

  11. Study on Curing Kinetics of Heat-resistant Flexible Polyamide Modified Epoxy Resin Adhesive

    Directory of Open Access Journals (Sweden)

    Hua Li

    2015-04-01

    Full Text Available In order to study the effects of numerous variables affecting the reaction rate of heat-resistant flexible modified epoxy resin adhesive, the curing kinetics of polyamide modified epoxy resin was studied. The heat-resistant flexible modified epoxy resin adhesive cured at room-temperature was prepared with epoxy resin, polysulfide rubber and organosilicone as adhesive component, polyamide as main curing agent and addition of different modified filler and the curing agent containing benzene ring structure. The curing kinetics of polyamide modified epoxy resin was studied by Differential Scanning Calorimetry (DSC at different heating speeds and the characteristic temperatures of the curing process were analyzed and confirmed. the kinetics parameters of activation energy was calculated using Flynn-Wall-Ozawa equation and Kissinger equation, respectively, then the kinetic model of curing reaction was built as d&alpha/dt = 4.38×107 exp (-57740/RT (1-&alpha0.93, the results show that the two-parameter model is adequate to represent the curing reaction process, the model can well describe the curing reaction process of the studied resin. The DSC curves obtained using the experimental data show a good agreement with that theoretically calculated. The research results will provide theoretical basis for the choice of manufacturing process and the optimization of processing window.

  12. Heat-Resistant Co-W Catalytic Metals for Multilayer Graphene Chemical Vapor Deposition

    Science.gov (United States)

    Ueno, Kazuyoshi; Karasawa, Yusuke; Kuwahara, Satoru; Baba, Shotaro; Hanai, Hitoshi; Yamazaki, Yuichi; Sakuma, Naoshi; Kajita, Akihiro; Sakai, Tadashi

    2013-04-01

    Multilayer graphene (MLG) is expected to be a low-resistance and high-reliability interconnect material replacing copper (Cu) in nanoscale interconnects. Chemical vapor deposition (CVD) on catalytic metals is expected as a practical method for MLG deposition. To obtain high-quality MLG films without catalyst agglomeration by CVD, heat-resistant Co-W catalytic metals were investigated. The agglomeration of the Co-W catalytic metals was suppressed by increasing the W composition; however, MLG deposition was suppressed at the same time. The effects of W addition on the MLG growth were discussed from the viewpoints of the crystallographic change of the Co-W catalysts and chemical reactions. It was found that the Co grain size was reduced and the fcc Co formation was suppressed by W addition. In addition, graphite formation was supposed to be suppressed by W addition owing to the formation of phases other than fcc Co according to the Co-W-C phase diagram. With the optimum W concentration, MLG crystallinity was improved by high-temperature CVD using the heat-resistant Co-W catalytic metals (0.7 at. %) without agglomeration, compared with that in the case of using pure-Co catalysts.

  13. [Heat resistance of aldolase of the hybrid embryos of sea urchins Strongylocentrotus droebachiensis and S, intermedius].

    Science.gov (United States)

    Neifakh, A A; Kusakina, A A; Ivanenkov, V V; Glushankova, M A

    1976-01-01

    The time of expression of the genes controlling aldolase has been studied in the hybrid embryos female Strongylocentrotus droebachiensis X male S. intermedius. The enzyme heat resistance estimated by the temperature of 50% inactivation following the exposition for 30 min (T50) was used as its genetic marker. T50 of aldolase of the psychrophilic maternal species suffered practically no changes from the stage of mesenchyme blastula till the stage of 11 days old pluteus and equated 35.3 degrees. T50 of aldolase of autumn- and spring-spawning populations of the thermophilic paternal species equaled 39.5 degrees at the stage of 11 days old pluteus. The heat resistance of aldolase of the hybrid embryos did not differ reliably from that of maternal enzyme during the first 4 days of development (at 8 degrees) till the late gastrula stage and attained the maximum (T50 =36.9 degrees) on the 8th day (stage of pluteus). The expression of the genes controlling aldolase appears to take place between these developmental stages. PMID:934595

  14. Two distinct groups within the Bacillus subtilis group display significantly different spore heat resistance properties.

    Science.gov (United States)

    Berendsen, Erwin M; Zwietering, Marcel H; Kuipers, Oscar P; Wells-Bennik, Marjon H J

    2015-02-01

    The survival of bacterial spores after heat treatment and the subsequent germination and outgrowth in a food product can lead to spoilage of the food product and economical losses. Prediction of time-temperature conditions that lead to sufficient inactivation requires access to detailed spore thermal inactivation kinetics of relevant model strains. In this study, the thermal inactivation kinetics of spores of fourteen strains belonging to the Bacillus subtilis group were determined in detail, using both batch heating in capillary tubes and continuous flow heating in a micro heater. The inactivation data were fitted using a log linear model. Based on the spore heat resistance data, two distinct groups (p flow heating, the z-values were significantly different, hence extrapolation from one system to the other was not justified. This study clearly shows that heat resistances of spores from different strains in the B. subtilis group can vary greatly. Strains can be separated into two groups, to which different spore heat inactivation kinetics apply. PMID:25481058

  15. Development and properties of new 10Cr-2Mo-V-Nb heat resisting steel

    International Nuclear Information System (INIS)

    For the development of a new ferritic heat resisting steel which shows excellent characteristics in creep rupture strength, weldability, resistance to oxidation, and corrosion resistance to sodium and steam at the service temperature of 5000 to 6000C, extensive studies have been carried out. The main results are as follows: (1) 0.05C-10Cr-2Mo-0.1V-0.05Nb steel is obtained, whose creep rupture strength at 6000C is superior to that of SUS 304 (18-8 stainless steel). (2) This steel comprises two phases: delta-ferrite and tempered martensite. Main precipitates after longer term at 6000 to 7000C are M23C6 and Fe2Mo. Fe2Mo, a stable precipitate in ferrite, contributes to the creep rupture strength at longer term. (3) Ferritic heat resisting steel of this type is promising not only for the boiler tube use but for the fast breeder reactor steam generator use, since it has excellent high temperature strength and the resistance to oxidation and corrosion. (author)

  16. Guidelines for experimental design protocol and validation procedure for the measurement of heat resistance of microorganisms in milk.

    Science.gov (United States)

    Condron, Robin; Farrokh, Choreh; Jordan, Kieran; McClure, Peter; Ross, Tom; Cerf, Olivier

    2015-01-01

    Studies on the heat resistance of dairy pathogens are a vital part of assessing the safety of dairy products. However, harmonized methodology for the study of heat resistance of food pathogens is lacking, even though there is a need for such harmonized experimental design protocols and for harmonized validation procedures for heat treatment studies. Such an approach is of particular importance to allow international agreement on appropriate risk management of emerging potential hazards for human and animal health. This paper is working toward establishment of a harmonized protocol for the study of the heat resistance of pathogens, identifying critical issues for establishment of internationally agreed protocols, including a harmonized framework for reporting and interpretation of heat inactivation studies of potentially pathogenic microorganisms. PMID:25305440

  17. High-temperature gas-cooled reactor helium compatibility studies: results of 10,000-hour exposure of selected alloys in simulated reactor helium

    International Nuclear Information System (INIS)

    Work on the HTGR Helium Compatibility Task accomplished during the period March 31, 1977 through September 30, 1979, is documented in this report. Emphasis is on the results and analyses of creep data to 10,000 h and the detailed metallurgical evaluations performed on candidate alloy specimens tested for up to 10,000 h. Long-term creep and unstressed aging data in controlled-impurity helium and in air at 800, 900, and 10000C are reported for alloys included in the program in FY-76, including the wrought solid-solution-strengthened alloys, Hastelloy X, Hastelloy S, RA 333, and HD 556, and the centrifugally cast austenitic alloys, HK 40, Supertherm, Manaurite 36X, Manaurite 36XS, and Manaurite 900

  18. Data on post irradiation experiments of heat resistant ceramic composite materials. PIE for 97M-13A

    Energy Technology Data Exchange (ETDEWEB)

    Baba, Shin-ichi; Ishihara, Masahiro; Souzawa, Shizuo [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Sekino, Hajime [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    The research on the radiation damage mechanism of heat resistant ceramic composite materials is one of the research subjects of the innovative basic research in the field of high temperature engineering, using the High Temperature engineering Test Reactor (HTTR). Three series of irradiation tests on the heat resistant ceramic composite materials, first to third irradiation test program, were carried out using the Japan Material Testing Reactor (JMTR). This is a summary report on the first irradiation test program; irradiation induced dimensional change, thermal expansion coefficient, X-ray diffraction and {gamma}-ray spectrum are reported. (author)

  19. Thermal, epithermal and thermalized neutron attenuation properties of ilmenite-serpentine heat resistant concrete shield

    International Nuclear Information System (INIS)

    Experimental measurements were carried out to study the attenuation properties of low-energy neutrons transmitted through unheated and preheated barriers of heavy-weight, highly hydrated and heat-resistant concrete shields. The concrete shields under investigation have been prepared from naturally occurring ilmenite and serpentine Egyptian ores. A collimated beam obtained from an Am-Be source was used as a source of neutrons, while the measurements of total thermal, epithermal, and thermalized neutron fluxes were performed using a BF-3 detector, multichannel analyzer and Cd filter. Results show that the ilmenite-serpentine concrete proved to be a better thermal, epithermal and thermalized neutron attenuator than the ordinary concrete especially at a high temperature of concrete exposure. (Author)

  20. Preparation of heat-resistant silicon carbide fiber from polycarbosilane fiber cured by electron beam irradiation

    International Nuclear Information System (INIS)

    Heat-resistant silicon carbide (SiC) fiber was synthesized by the heat treatment of polycarbosilane (PCS) fiber with electron beam irradiation curing. PCS fiber was irradiated up to 10 - 15 MGy by 2 MeV electron beam under He gas atmosphere, then the fiber was well cured. The SiC fiber obtained from the radiation cured PCS fiber contained lesser oxygen comparing with the Si-C-O fiber 'Nicalon', which was synthesized by thermal oxidation curing of PCS fiber and contained oxygen of about 10 wt%. The thermal decomposition temperature of Si-C-O fiber increased by decrease of oxygen content in the fiber. For the very low oxygen content (0.35 wt%) fiber, the tensile strength and the Young's modulus was 2.5 GPa and 250 GPa, respectively, after heat treatment at 1,973 K. Applying this radiation curing technique, long size of SiC fiber (several 100g) was synthesized. (author)

  1. Preparation of flexible and heat-resisting conductive transparent film by the pyrosol process

    International Nuclear Information System (INIS)

    A pyrosol process was successfully applied for the preparation of a flexible, conductive, and transparent inorganic film, a tin-doped indium oxide (ITO) film lined with a thin mica layer. This flexible heat-resistant ITO-mica film exhibited high conductivity and transparency, comparable to ITO deposited on glass substrate. The minimum radius of bending for the film, without any recognizable change in the conductivity and appearance, was 8 mm. The ITO deposited on mica showed a large (222) diffraction peak with a smaller (400) peak, in contrast to ITO deposited with (400) orientation on an ordinary glass substrate. Using the ITO-mica film, a prototype model of a flexible organic light emitting diode was fabricated

  2. Structure and mechanical properties of low-activated heat-resistant reactor steel

    International Nuclear Information System (INIS)

    A low-activated high-strength heat-resistant steel type 15Kh2V2FA-A is designed and intended to be used for reactor vessels of increased safety and service life. The steel provides an induced radioactivity level approximately hundred times lower compared to commonly used molybdenum-bearing steels for a 40- year period after reactor shutdown. Comprehensive kinetic studies of phase and structural transformations in austenite of commercial steel are carried out and optimum heat treatment conditions are determined. For the first time a 52-t ingot of ultrahigh purity steel is cast and two reactor vessel shells 170 and 375 mm thick are manufactured by forging. It is shown that the resistance to brittle fracture and the level of tensile properties of the steel proposed meet the requirements to reactor steels

  3. Microstructural Characterization for Structural Health Monitoring of Heat-Resisting Rotor Steels

    International Nuclear Information System (INIS)

    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

  4. Estimating the Condition of the Heat Resistant Lining in an Electrical Reduction Furnace

    Directory of Open Access Journals (Sweden)

    Jan G. Waalmann

    1988-01-01

    Full Text Available This paper presents a system for estimating the condition of the heat resistant lining in an electrical reduction furnace for ferrosilicon. The system uses temperature measured with thermocouples placed on the outside of the furnace-pot. These measurements are used together with a mathematical model of the temperature distribution in the lining in a recursive least squares algorithm to estimate the position of 'the transformation front'. The system is part of a monitoring system which is being developed in the AIP-project: 'Condition monitoring of strongly exposed process equipment in thc ferroalloy industry'. The estimator runs on-line, and results arc presented in colour-graphics on a display unit. The goal is to locate the transformation front with an accuracy of +- 5cm.

  5. Analysis of cyclic plastic response of heat resistant Sanicro 25 steel at ambient and elevated temperatures.

    Czech Academy of Sciences Publication Activity Database

    Polák, Jaroslav; Petráš, Roman; Heczko, Milan; Kruml, Tomáš; Chai, G.

    Amsterdam : Elsevier, 2014 - (Gulagliano, M.; Vergani, L.), s. 68-73 ISSN 1877-7058. - (Procedia Engineering. 74). [ICMFM 2014 International Colloquium on Mechanical Fatigue of Metals /17./. Verbania (IT), 25.06.2014-27.06.2014] R&D Projects: GA ?R(CZ) GA13-23652S Institutional support: RVO:68081723 Keywords : heat resistant steel * Sanicro 25 * cyclic plasticity * dislocation structure * effect of temperature Subject RIV: JL - Materials Fatigue, Friction Mechanics http://ac.els-cdn.com/S1877705814007966/1-s2.0-S1877705814007966-main.pdf?_tid=8150a71a-543c-11e4-b10e-00000aab0f27&acdnat=1413358137_888616b4b84bb7ddf28dfaee5358a90a

  6. Heat resistance of dermatophyte's conidiospores from athletes kits stored in Nigerian University Sport's Center.

    Science.gov (United States)

    Essien, J P; Jonah, I; Umoh, A A; Eduok, S I; Akpan, E J; Umoiyoho, A

    2009-03-01

    The incidence and heat resistance of conidiospores produced by dermatophytes isolated from athlete's kits (canvasses, stockings and spike shoes) stored in Nigerian University Sport's Centre were investigated. Epidermophyton floccosum, Microsporum oudouinii, Microsporum canis, Trichophyton concentricum, Trichophyton mentagrophytes and Trichophyton rubrum were isolated and their incidence on the athlete's kits varied with the species and type of kits. Among the isolates T. mentagrophytes, T. rubrum and E. floccosum with 25%, 23% and 20% prevalence rates respectively, were the most common isolates, and are often associated with tinea pedis (athletes foot). Canvasses with the highest incidence of dermatophytes (25 out of 34 fungal isolates) were the most contaminated kits and could serve as effective articles for the transmission of tinea pedis among athletes in Nigeria. The common etiological agents screened, produced asexual spores (conidiospores) that exhibited high resistance to heat treatment at 80 degrees C. Of the three isolates, E. floccosum, with a decimal reduction time (D-value) of D80 = 4.4 min was the most resistant followed by T. mentagrophytes with D80 = 4.0 min and then T. rubrum with D80 = 3.2 min. The spores elimination pattern indicates that increasing the heating duration would decrease the decimal reduction time and possibly denature the fungal propagules but may damage the skin during treatment with hot water compresses. The findings have shown that the use of hot water compresses is palliative but heat treatment especially vapour-heat treatment offers adequate preventive measures if applied for periodic treatment of contaminated kits. However, determining the correct condition for effective decontamination will require detailed understanding of the heat resistance of fungal spores. Otherwise treatment of kits with detergent and chaotropic agent such as urea and guanidinium salt is preferred to heat treatment. PMID:19388558

  7. Segregation in welded nickel-base alloys

    International Nuclear Information System (INIS)

    Segregation effects have been investigated in nickel-base alloys monel 400, inconel 625, hastelloy C-276 and incoloy 825, test welded under controlled conditions. Deviations from the normal composition have been observed to varying extents in the welded zone of these alloys. Least effect of this type occurred in Monel 400 where the content of Cu increased in some of the areas. Enhancement of Al and Ti has been found over large areas in the other alloys which has been attributed to the formation of low melting slag. Another common feature is the segregation of Cr, Fe or Ti, most likely in the form of carbides. Enrichment of Al, Ti, Nb, Mb, Mo, etc., to different amounts in some of the areas of these materials is in- terpretted in terms of the formation of gamma prime precipitates or of Laves phases. (author)

  8. Influence of carburisation on the ductility of four high temperature alloys

    International Nuclear Information System (INIS)

    The influence of carburisation and thermal exposure on the room temperature ductility of Alloy 800 H, Inconel 617, Hastelloy X and Nimonic 86 has been investigated. It was found that carburisation affects the ductility of Alloy 800 H much less severely than that of the nickel-base alloys. This is explained in terms of the varying volume fractions of carbide formed for a particular carbon content as the result of, first, different carbon solubilities in the iron and nickel-base materials and, second, the formation of carbides with different metal: carbon stoichiometry ratios. (author)

  9. Influence of yttrium microalloying on phase stability of the ZhS6U alloy

    International Nuclear Information System (INIS)

    The role of yttrium in phase transformations of the ZhS6U heat resistance nickel base alloy is investigated. It is established that the increase of yttrium content decreases the quantity of ?'-phase, that relates to the decrease of alloying elements when modifying the melt by the nickel-yttrium alloy containing 90% Ni. Carbides precipitating in the alloy have mainly a round form with yttrium content in the range from 0.01 to 0.05%. ''Chinese type'' carbides is precipitated in the alloy with lower yttrium content. Yttrium in quantity of 0.01% decelerates phase reactions, that influences favourably on alloy durability

  10. Transformation processes during annealing of Al-amorphous alloys

    International Nuclear Information System (INIS)

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

  11. Effects of alpha-tocopherol addition to polymeric coatings on the UV and heat resistance of a fibrous collagen material--chrome-free leather

    Science.gov (United States)

    UV and heat resistance are very important qualities of leather because most leather products are constantly exposed to outdoor environments. In recent years, we have focused on using environmentally friendly antioxidants that will improve the UV and heat resistance of chrome-free leather. Tocopher...

  12. Fundamental studies on electron beam welding on heat-resistant superalloys for nuclear plants, 1

    International Nuclear Information System (INIS)

    In this paper, the effect of welding conditions on some characteristics of weld bead in electron beam welding was made clear, concerning such superalloys for the nuclear plants as Hastelloy-type, Inconel-type and Incoloy-type ones. Obtained conclusions may be summarized as follows, using technical symbols which are given meanings in this report. 1) The weld defects are R-porosity at the root of the penetration and a microcrack observed continuously in the interdendritic boundary of weld metal and the grain boundary of heat affected zone. 2) R-porosity occurs within the individual areas on W sub(R)-a sub(b) diagram. Superalloys can be evaluated in the susceptibility to the R-porosity in terms of S sub(P) and ?a sub(b). 3) From the relation between heat input and microcracking percentage, microcracks occur at and below a certain heat input. This critical heat input is herein defined as q sub(cr) to avoid microcracks which is regarded as one of the proper criteria to evaluate the superalloys in the susceptibility to microcracking. 4) Most microcracks are apt to occur when h sub(C)/h sub(N) comes near to 1.0. When microcracking position is arranged on h sub(P)-h sub(P) diagram, h sub(C)/h sub(P) generally tends to decrease with the increase in h sub(P) in all the superalloys except for Incoloy 800. Moreover, this value is scattered in the individual area of h sub(N)/h sub(P). (auth.)

  13. The corrosion resistance of heat proof nickel alloy in molten fluoride salts

    International Nuclear Information System (INIS)

    Studies have been made into corrosion and mechanical properties of high-nickel alloys at NSC KIPT on the basis of high-purity metal components. Corrosion tests of the Hastelloy-type alloy in fluoride melts at 650 degree C revealed formation of no films in the process of corrosion during 700 h. The corrosion of the alloy under study in molten fluorides is characterized by a weak interaction of melt components with the alloy, by penetration of Zr and Na atoms into the alloy at a depth of 3 to 5 ?m over 700 h, by the absence of oxide films on the surface. The chromium content in the near-surface layer of the alloy decreases to the depth of 10 ?m. Corrosion tests cause no essential changes in the mechanical properties of the alloy

  14. Cr - Ni system alloys composition impact on durability value

    Directory of Open Access Journals (Sweden)

    A. Z. Issagulov

    2014-10-01

    Full Text Available There are considered the alloys of the Cr – Ni system with addition of iron, molybdenum and other alloying elements. In the alloys there varied chrome content from 35 to 55 %. The alloys were subjected to various types of heat treatment. There were measured mechanical properties at the room temperature, then the alloys were studied for the durability limit. There was additionally studied the impact of chrome content in the alloy and operation temperatures on the value of rupture stress. All the indicators studied were compared with similar parameters of the ??77??? alloy.It was established that in terms of heat resistance with the present combination of alloying elements the most optimal chrome content is 40…45 %.

  15. Feasibility study on potential productivity of heat-resisting and advanced semiconductors by using the HTTR

    International Nuclear Information System (INIS)

    Worldwide attention has been paid to GaAs and SiC as a kind of the heat-resisting and advanced semiconductor materials. Doping of specific impurities into semiconductor materials is a key technology for producing semiconductor devices. As one of doping technologies, thermal diffusional doping has been successfully applied to Si. Application of thermal diffusional doping to GaAs needs expensive and complicated processes in order to prevent an occurrence of lattice defects by impurities. On the other hand, it is difficult to apply this technology to SiC, because of small diffusion coefficient of impurities to SiC. Therefore, it is of great importance to develop a substitutional doping technology for these materials for realizing heat-resisting and advanced semiconductor. To dope some impurities into Si crystal by using neutron irradiation is a mature technology and is called NTD. The High Temperature engineering Test Reactor(HTTR) has an unique and superior capability to irradiate large-sized specimen, in the order of 10cm in diameter, at high temperature up to approximately 1000degC. This report presents a result of feasibility study of potential applicability and effectiveness of NTD to GaAs and SiC at the HTTR. First of all, advantages and disadvantages were identified by reviewing the state-of-the-art technology of NTD to Si. Potential applicability of NTD to GaAs and SiC are discussed. Based on this discussion, effectiveness and feasibility of NTD to these materials at the HTTR are examined. As a result, NTD is feasible to SiC but not to GaAs. The HTTR provides the capability to produce SiC semiconductor, in particular, to produce the semiconductor with (1) low irradiation damage, (2) uniform distribution of doped impurities and (3) high productivity, if a large-sized SiC crystal is capable to be commercialized. Practical application of NTD at the HTTR will be discussed in the next study. (author)

  16. Investigation of the isothermal precipitation behaviour of nickel-base alloys using electrochemical phase extraction

    International Nuclear Information System (INIS)

    Electrochemical phase extraction methods have been developed empirically for the selective separation of the precipitates in metallic materials. A detailed description of the process has been undertaken to allow optimization for various nickel-base alloys. For this part of the investigation, 16 model alloys were prepared as test electrodes and the electrolyte composition was varied over a wide range. The results enabled a series of effects to be explained on the basis of electrochemical data. The large number of test parameters limited the scope of the preliminary experiments and the range of model alloys used. In the nickel-base alloys, titanium carbo-nitride and primary M6C precipitates were identified. During isothermal ageing, M23C6 (except in Alloy KSN), Ni3Al (in INCONEL 617), Laves phases (in Hastelloy X and INCONEL 617), M12C (in HASTELLOY X and INCONEL 617) and ?-tungsten (in the tungsten-containing alloys) were precipitated. The precipitation behaviour changed in the alloys investigated from intracrystalline to intercrystalline with increasing ageing temperature. The intracrystalline secondary precipitations affect the microhardness, structure and the solid-solution lattice. (orig.)

  17. Effect of temperature on the physical properties of ilmenite-serpentine heat resistant concrete radiation shields

    International Nuclear Information System (INIS)

    A series of experimental studies has been carried out to determine the change in unit weight, compressive strength, water content and neutron macroscopic cross section of a new type of concrete shields made from egyptian limonite and serpentine ores when heated for long period at temperatures up to 600 degree C. Results show that the unit weight of the cure concrete has a value 2.98 Ton/M3 and decreases with increasing temperature, while the compressive strength reaches a maximum value of 19 Ton/M2 at 100 degree C. The differential thermal analysis (D.T.A.)of this concrete shows three endothermic peaks at 100 degree C, 480 degree C. Also, the thermogravimetry analysis (T.G.A.) shows that the cure concrete retains about 11% water content of the total sample weight and still retains 4.5% of its initial value when heated for long period at 600 degree C. Results also show that the neutron macroscopic cross section (for neutrons of energies <1 MeV) of the limonite-serpentine heat resistant concrete decreases to 18.6% of its initial value after heating 600 degree C

  18. Fundamental studies on electron beam welding of heat-resistant superalloys for nuclear plants, (1)

    International Nuclear Information System (INIS)

    In this paper, the effect of the welding conditions on the characteristics of the weld geometry and the weld defects was made clear, concerning the heat-resistant superalloys for the nuclear plants. Obtained conclusion may be summarized as follows, using technical symbols which are given meaning in this report. 1) The weld defects were R-porosity and microcrack. 2) S sub(p) and ?a sub(b) are considered to be the important criteria for the evaluation of the susceptibility to the R-porosity. 3) Superalloys could be evaluated in the sensitivity to the microcrack in terms of the critical heat input to avoid microcrack q sub(cr). This q sub(cr) is considered to be one of the proper criteria for evaluating the superalloys in the susceptibility to the microcrack. 4) Most microcracks were apt to occur when h sub(c)/h sub(N) came near to 1.0. These microcracks came to occur easily with the increase of d sub(B.N)/d sub(B). (auth.)

  19. Creep deformation characterization of heat resistant steel by stress change test

    International Nuclear Information System (INIS)

    To evaluate the creep deformation mechanism of heat resistant steel, stress change tests were conducted during creep tests for Modified 9Cr-1Mo Steel and 2.25Cr-1Mo Steel. In this study it was confirmed that the dislocation behavior during the creep tests was in viscous manner because of no instantaneous plastic strain observed at stress increments. Transient backward creep behavior was observed after stress reduction for these steels in this work. Mobilities of dislocation were evaluated by observed backward creep behavior after stress reductions. Internal stresses were evaluated by the changes of creep rate in stress increments. And mobile dislocation densities were evaluated with the estimated mobilities of dislocation and the changes of creep rate in stress increments. It was found that the variation of evaluated mobile dislocation densities during creep deformation showed the same tendency as the variation of creep rate. Therefore mobile dislocation density is the dominant factor that influences the creep rate variation in creep deformation of these steels in this work. The mobilities of dislocation showed a good correlation with 1/T and related with solute amount of Mo that is a solution hardening element.

  20. Laves phase evolution in a modified P911 heat resistant steel during creep at 923 K

    Energy Technology Data Exchange (ETDEWEB)

    Kipelova, A., E-mail: a.kipelova@gmail.com [Belgorod State University, Pobeda 85, Belgorod 308015 (Russian Federation); Belyakov, A.; Kaibyshev, R. [Belgorod State University, Pobeda 85, Belgorod 308015 (Russian Federation)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer Laves phase particles appear mainly on high-angle boundaries. Black-Right-Pointing-Pointer Volume fraction of Laves phase increases to saturation during creep for about 3000 h. Black-Right-Pointing-Pointer Sizes of Laves phase particles are expressed by power law functions of creep time. Black-Right-Pointing-Pointer Grow exponents of 6.7 and 8.3 are obtained for particles located on HABs and LABs. - Abstract: The evolution of Fe{sub 2}(W, Mo) Laves phase in a 3%Co modified P911 heat resistant steel was examined during creep tests at 923 K. The tempered martensite lath structure evolved after heat treatment was characterized by dispersion of MX carbonitrides and M{sub 23}C{sub 6} carbides. Appearance of Laves phase particles was recorded after a creep strain of 1%. The mean size of Laves phase particles increased from 190 to 265 nm with increasing strain to 18%. The Laves phase particles were spaced on various boundaries including low-angle boundaries (LABs) of laths/subgrains, but most of these particles (about 90%) were located on high-angle boundaries (HABs) at all strains studied. The size of Laves phase particles located on HABs was larger and their coarsening kinetics was faster than those precipitated on LABs. It is assumed that the evolution of Laves phase during creep is controlled by the grain boundary diffusion of tungsten and molybdenum.

  1. Characterization and radiation response of a heat-resistant variant of V79 cells

    International Nuclear Information System (INIS)

    A thermoresistant variant of the established cell line V79-S171-W1 was isolated after treatment with nitrosoguanidine and repeated heat treatments at 42.6 to 430C, and showed an enhanced ability to survive at 42.6, 43.5, and44.50C. The rates of inactivation of the normal and heat-resistant lines differed by approximately a factor of 2 over this temperature range. This level of thermoresistance was stable for the first 80 doublings, but was lost by 120 doublings. This may have been due to a reversion to the normal V79 line since there was no continuous selection pressure and the thermoresistant variant, which was designated at HR7, had a longer average doubling time. Transient thermotolerance was induced in both the V79 and HR7 cells by a 10-min expsure to 44.50C. After 3 hr incubation at 370C, both cell lines had an identical sensitivity to further exposure to 44.50C. Thus the long-term thermoresistance of the HR7 cells may be due to a permanent induction of a low level of thermotolerance. The (ionizing) radiation survival curves and the ability to repair sublethal radiation damage were identical for the thermoresistance variant and the parent cell line

  2. Characterization and radiation response of a heat-resistant variant of V79 cells

    International Nuclear Information System (INIS)

    A thermoresistant variant of the established cell line V79-S171-W1 was isolated after treatment with nitrosoguanidine and repeated heat treatments at 42.6 to 43 degrees C, and showed an enhanced ability to survive at 42.6, 43.5, and 44.5 degrees C. The rates of inactivation of the normal and heat-resistant lines differed by approximately a factor of 2 over this temperature range. This level of thermoresistance was stable for the first 80 doublings, but was lost by 120 doublings. This may have been due to a reversion to the normal V79 line since there was no continuous selection pressure and the thermoresistant variant, which was designated at HR7, had a longer average doubling time. Transient thermotolerance was induced in both the V79 and HR7 cells by a 10-min exposure to 44.5 degrees C. After 3 hr incubation at 37 degrees C, both cell lines had an identical sensitivity to further exposure to 44.5 degrees C. Thus the long-term thermoresistance of the HR7 cells may be due to a permanent induction of a low level of thermotolerance. The (ionizing) radiation survival curves and the ability to repair sublethal radiation damage were identical for the thermoresistant variant and the parent cell line

  3. Polyphasic taxonomy of the heat resistant ascomycete genus Byssochlamys and its Paecilomyces anamorphs

    DEFF Research Database (Denmark)

    Samson, R.A.; Houbraken, J.

    2009-01-01

    Byssochlamys and related Paecilomyces strains are often heat resistant and may produce mycotoxins in contaminated pasteurised foodstuffs. A comparative study of all Byssochlamys species was carried out using a polyphasic approach to find characters that differentiate species and to establish accurate data on potential mycotoxin production by each species. Phylogenetic analysis of the ITS region, parts of the P-tubulin and calmodulin genes, macro- and micromorphological examinations and analysis of extrolite profiles were applied. Phylogenetic analyses revealed that the genus Byssochlamys includes nine species, five of which form a teleomorph, i.e. B. fulva, B. lagunculariae, B. nivea, B. spectabilis and B. zollemiae, while four are asexual, namely P. brunneolus, P. divaricatus, P. formosus and P. saturatus. Among these, B. nivea produces the mycotoxins patulin and byssochlamic acid and the immunosuppressant mycophenolic acid. Byssochlamys lagunculariae produces byssochlamic acid and mycophenolic acid and thuschemically resembles B. nivea. Some strains of P saturatus produce patulin and brefeldin A, while B. spectabilis (anamorph P. variotii s.s.) produces viriditoxin. Some micro- and macromorphological characters are valuable for identification purposes, including the shape and size of conidia and ascospores, presence and ornamentation of chlamydospores, growth rates on MEA and CYA and acid production on CREA. A dichotomous key is provided for species identification based on phenotypical characters.

  4. The technology for automated development of economically doped heat-resistant nickel superalloys

    Directory of Open Access Journals (Sweden)

    Shmotin Yuriy

    2014-01-01

    Full Text Available The paper presents the usage of computational technology, aimed at automated search for optimum compositions of nickel superalloys, being minimally doped by expensive rhenium and having no ruthenium. Resulting doping compositions ensure ultimate long-term high-temperature strength. The technology is based on computer model of alloy and numerical optimization routine. The model computes relation between an alloy composition and its performance characteristics. Multiobjective optimization procedure provides for an automated search for alloy composition to ensure the set of pre-defined properties of a new material. Two new nickel-based single-crystal superalloys are presented, which were created using this technology. SLGS-3 features high-temperature strength (100 hours at 1,000 degrees Centigrade at approximately 345?MPa. Its composition does not contain ruthenium. SLGS-1 alloy provided for 265?MPa and contained neither rhenium nor ruthenium in its composition.

  5. Salt Fog Testing Iron-Based Amorphous Alloys

    International Nuclear Information System (INIS)

    Iron-based amorphous alloys are hard and highly corrosion resistant, which make them desirable for salt water and other applications. These alloys can be produced as powder and can be deposited as coatings on any surface that needs to be protected from the environment. It was of interest to examine the behavior of these amorphous alloys in the standard salt-fog testing ASTM B 117. Three different amorphous coating compositions were deposited on 316L SS coupons and exposed for many cycles of the salt fog test. Other common engineering alloys such as 1018 carbon steel, 316L SS and Hastelloy C-22 were also tested together with the amorphous coatings. Results show that amorphous coatings are resistant to rusting in salt fog. Partial devitrification may be responsible for isolated rust spots in one of the coatings. (authors)

  6. An all-fiber, polarized, core-pumped heat-resistant thulium-doped master oscillator power amplifier

    International Nuclear Information System (INIS)

    We present an all-fiber, polarized, core-pumped heat-resistant thulium-doped master oscillator power amplifier (MOPA) system. The laser operated at a wavelength of 1926.7 nm with a spectral linewidth of less than 70 pm. For a repetition rate of 100 kHz, a maximum average power of 750 mW with a slope efficiency of 48.8% and pulse duration of 41 ns was achieved. Even without active cooling, no observable thermal effects occurred when the laser was operated at room temperature. To the best of our knowledge, this core-pumped heat-resistant MOPA configuration is the first reported in the 2 ?m region. (paper)

  7. Extreme Heat Resistance of Food Borne Pathogens Campylobacter jejuni, Escherichia coli, and Salmonella typhimurium on Chicken Breast Fillet during Cooking.

    DEFF Research Database (Denmark)

    de Jong, Aarieke E I; van Asselt, Esther D

    2012-01-01

    The aim of this research was to determine the decimal reduction times of bacteria present on chicken fillet in boiling water. The experiments were conducted with Campylobacter jejuni, Salmonella, and Escherichia coli. Whole chicken breast fillets were inoculated with the pathogens, stored overnight (4°C), and subsequently cooked. The surface temperature reached 70°C within 30 sec and 85°C within one minute. Extremely high decimal reduction times of 1.90, 1.97, and 2.20 min were obtained for C. jejuni, E. coli, and S. typhimurium, respectively. Chicken meat and refrigerated storage before cooking enlarged the heat resistance of the food borne pathogens. Additionally, a high challenge temperature or fast heating rate contributed to the level of heat resistance. The data were used to assess the probability of illness (campylobacteriosis) due to consumption of chicken fillet as a function of cooking time. The data revealed that cooking time may be far more critical than previously assumed.

  8. Sustainable, heat-resistant and flame-retardant cellulose-based composite separator for high-performance lithium ion battery

    OpenAIRE

    Jianjun Zhang; Liping Yue; Qingshan Kong; Zhihong Liu; Xinhong Zhou; Chuanjian Zhang; Quan Xu; Bo Zhang; Guoliang Ding; Bingsheng Qin; Yulong Duan; Qingfu Wang; Jianhua Yao; Guanglei Cui; Liquan Chen

    2014-01-01

    A sustainable, heat-resistant and flame-retardant cellulose-based composite nonwoven has been successfully fabricated and explored its potential application for promising separator of high-performance lithium ion battery. It was demonstrated that this flame-retardant cellulose-based composite separator possessed good flame retardancy, superior heat tolerance and proper mechanical strength. As compared to the commercialized polypropylene (PP) separator, such composite separator presented impro...

  9. Certain characteristics of the development of fatigue and creep in heat-resistant alloys under asymmetric high-cycle loading

    Energy Technology Data Exchange (ETDEWEB)

    Golub, V.P.

    1984-08-01

    The high-temperature fatigue and creep behavior of nickel superalloys is examined from the standpoint of thermal activation. An analysis is made of experimental data on the activation energies of fracture of nickel-base superalloys, EI867, EP109, and VZhU12U, for stress ratios from zero to infinity. It is found that a discontinuous change in the activation energy of fracture occurs in the stress region corresponding to the transition from fatigue to creep. 17 references.

  10. Collect Available Creep-Fatigue Data and Study Existing Creep-Fatigue Evaluation Procedures for Grade 91 and Hastelloy XR

    International Nuclear Information System (INIS)

    This report describes the results of investigation on Task 5 of DOE/ASME Materials Project based on a contract between ASME Standards Technology, LLC (ASME ST-LLC) and Japan Atomic Energy Agency (JAEA). Task 5 is to collect available creep-fatigue data and study existing creep-fatigue evaluation procedures for Grade 91 steel and Hastelloy XR. Part I of this report is devoted to Grade 91 steel. Existing creep-fatigue data were collected (Appendix A) and analyzed from the viewpoints of establishing a creep-fatigue procedure for VHTR design. A fair amount of creep-fatigue data has been obtained and creep-fatigue phenomena have been clarified to develop design standards mainly for fast breeder reactors. Following this, existing creep-fatigue procedures were studied and it was clarified that the creep-fatigue evaluation procedure of the ASME-NH has a lot of conservatisms and they were analyzed in detail from the viewpoints of the evaluation of creep damage of material. Based on the above studies, suggestions to improve the ASME-NH procedure along with necessary research and development items were presented. Part II of this report is devoted to Hastelloy XR. Existing creep-fatigue data used for development of the high temperature structural design guideline for High Temperature Gas-cooled Reactor (HTGR) were collected. Creep-fatigue evaluation procedure in the design guideline and its application to design of the intermediate heat exchanger (IHX) for High Temperature Engineering Test Reactor (HTTR) was described. Finally, some necessary research and development items in relation to creep-fatigue evaluation for Gen IV and VHTR reactors were presented.

  11. Collect Available Creep-Fatigue Data and Study Existing Creep-Fatigue Evaluation Procedures for Grade 91 and Hastelloy XR

    Energy Technology Data Exchange (ETDEWEB)

    Tai Asayama; Yukio Tachibana

    2007-09-30

    This report describes the results of investigation on Task 5 of DOE/ASME Materials Project based on a contract between ASME Standards Technology, LLC (ASME ST-LLC) and Japan Atomic Energy Agency (JAEA). Task 5 is to collect available creep-fatigue data and study existing creep-fatigue evaluation procedures for Grade 91 steel and Hastelloy XR. Part I of this report is devoted to Grade 91 steel. Existing creep-fatigue data were collected (Appendix A) and analyzed from the viewpoints of establishing a creep-fatigue procedure for VHTR design. A fair amount of creep-fatigue data has been obtained and creep-fatigue phenomena have been clarified to develop design standards mainly for fast breeder reactors. Following this, existing creep-fatigue procedures were studied and it was clarified that the creep-fatigue evaluation procedure of the ASME-NH has a lot of conservatisms and they were analyzed in detail from the viewpoints of the evaluation of creep damage of material. Based on the above studies, suggestions to improve the ASME-NH procedure along with necessary research and development items were presented. Part II of this report is devoted to Hastelloy XR. Existing creep-fatigue data used for development of the high temperature structural design guideline for High Temperature Gas-cooled Reactor (HTGR) were collected. Creep-fatigue evaluation procedure in the design guideline and its application to design of the intermediate heat exchanger (IHX) for High Temperature Engineering Test Reactor (HTTR) was described. Finally, some necessary research and development items in relation to creep-fatigue evaluation for Gen IV and VHTR reactors were presented.

  12. 17th colloquium on long-time behaviour of heat-resistant steels and high-temperature materials

    International Nuclear Information System (INIS)

    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)

  13. The expression of the 70 kd heat shock proteins is altered in heat resistant HA-1 cells

    International Nuclear Information System (INIS)

    The authors have recently isolated a series of stable heat resistant variants from HA-1 Chinese hamster cells. Examination of two dimensional gels of total cell extracts indicated that the 70kd family of HSP were expressed at higher levels in these variants. After a mild heat treatment the maximal amounts of 70 kd HSP induced and the kinetics of induction were different in the variant lines. Essentially, the level of increase was greater and it occured sooner. A similar situation was observed in cells treated with HSP inducers other than heat, such as sodium arsenite and amino acid analogues. Short pulse labeling and pulse-chase experiments indicated that the alterations in 70 kd HSP expression in the variant lines were probably at the level of synthesis of the protein, not its degradation. Total cellular RNA was isolated from control and heated HA-1 cells and their heat resistant variants and was translated in vitro. Preliminary results indicate that the changes in 70 kd HSP synthesis observed in the heat resistant variants seem to be a reflection of altered levels of the respective mRNAs. Moreover, the authors also found that heated cells preferentially express the HSP mRNAs. This observation suggests that translational controls may play a role in the preferential synthesis of HSP in heated cells

  14. Thermonuclear reactor wall, method of manufacturing them, heat resistant shielding member for thermonuclear reactor wall and thermonuclear reactor

    International Nuclear Information System (INIS)

    Since carbon fibers have been oriented in the direction of a plate surface in usual heat resistant shielding plates for a thermonuclear reactor, heat conductivity along the direction of the plate thickness is not sufficient and temperature rises greatly at the surface of the heat resistant shielding plate due to the thermal load from plasmas. Accordingly, evaporization loss is remarkable and the working life as the reactor wall is short. In view of the above, the carbon fibers in heat resistant shielding members are oriented so as to intersect the boundary between the shielding members and support members for fixing them. As a production method, carbon fiber-woven clothes are impregnated with pitches and laminated, pitches are further impregnated into gaps formed upon pressure-sintering and then they are finally sintered at a temperature higher than 2800degC to apply graphitization. Thus, since it is possible to increase the heat conductivity along the direction of the plate thickness than the value along the direction of the plate surface and suppress the temperature rise at the heat receiving surface, the cooling effect can be improved to reduce the surface abrasion loss due to evaporization. (N.H.)

  15. Characterization of the behaviour of heat-resistant steels under cyclic creep conditions. Final report

    International Nuclear Information System (INIS)

    The creep behaviour of characteristic, heat-resistant steels under conditions of rectangular, cyclic creep loading can be derived from the standard creep behaviour under constant creep by applying the modified life-fraction rule. The relative life as the characteristic constant of this rule can be determined by means of a factor set composed of a cycle factor, a materials factor, and a temperature factor. The cycle factor depends on the variation of stress or temperature, or both, and on the value and extent of changes in loading. The materials factor depends on the steel type and the temperature factor is determined by the temperature level exceeding a steel-type-specific temperature close to the lowest service temperatures. It is possible to extend the factor set by an additional strain factor describing the relative tensile yield strength up to a given plastic strain. The product of the materials factor, temperature factor and, if applicable, the strain factor has to be interpolated towards the value of one for the case of transition to constant creep. By means of scatter band evaluations, average time-to-rupture curves and limiting creep stress curves have been measured for the steels subjected to cyclic loads, and after fitting to standard values, these curves have been incorporated into a LARA user program that can calculate expected values of the limiting creep time and the time-to-rupture under conditions of rectangular, cyclic loading, based on the modified lr, cyclic loading, based on the modified life-fraction rule and the factor set approach. (orig.)

  16. Alicyclobacillus acidoterrestris in pasteurized exotic Brazilian fruit juices: isolation, genotypic characterization and heat resistance.

    Science.gov (United States)

    McKnight, I C; Eiroa, M N U; Sant'Ana, A S; Massaguer, P R

    2010-12-01

    In this study, the population of Alicyclobacillus spp. was estimated in pasteurized exotic Brazilian fruit juices using the most probable number (MPN) technique followed by biochemical tests. Pasteurized passion fruit (n = 57) and pineapple (n = 50) juices were taken directly from Brazilian manufacturers. While Alicyclobacillus spp. was isolated from passion fruit juice, the microorganism was not found in any pineapple juice samples. A higher incidence of Alicyclobacillus was observed in samples taken in June and July (dry months in Brazil) in comparison to the other months (March, April, May and August), and the highest Alicyclobacillus counts were recovered from these samples(>23 MNP/100 mL). Sixteen (n = 16) Alicyclobacillus strains were typed using the randomly amplified polymorphic DNA method (RAPD-PCR). RAPD-PCR revealed great genetic similarity between the passion fruit juice strains and Alicyclobacillus acidoterrestris DSM 2498. The heat resistance of three isolates was determined, and the mean D(95°) (1.7 min) and z (7.6 °C) values in the passion fruit juice were not significantly different (p > 0.05) from those obtained for the DSM 2498 strain (D(95°) = 1.5 min and z = 7.1 °C). This is the first report on the isolation of A. acidoterrestris from exotic fruit juices such as passion fruit juice. It is worth pointing out the importance of applying good agricultural practices in the field and applying controls for the fruit selection and washing steps, as well as controlling the time/temperature conditions for pasteurization so as to reduce the incidence and chances of A. acidoterrestris spoilage in these juices. PMID:20832679

  17. Electrochemical impedance spectroscopy of metal alloys in the space transportation system launch environment

    Science.gov (United States)

    Calle, Luz

    1990-01-01

    AC impedance measurements were performed to investigate the corrosion resistance of 18 alloys under conditions similar to the Space Transportation System (STS) launch environment. The alloys were: (1) zirconium 702; (2) Hastelloy C-22, C-276, C-4, and B-2; (3) Inconel 600 and 825; (4) Ferralium 255; (5) Inco Alloy G-3; (6) 20Cb-3; (7) SS 904L, 304LN, 316L, 317L, and 304L; (8) ES 2205; and (9) Monel 400. AC impedance data were gathered for each alloy at various immersion times in 3.55 percent NaCl-0.1N HCl. Polarization resistance values were obtained for the Nyguist plots at each immersion time using the EQUIVALENT CIRCUIT software package available with the 388 electrochemical impedance software. Hastelloy C-22 showed the highest overall values for polarization resistance while Monel 400 and Inconel 600 had the lowest overall values. There was good general correlation between the corrosion performance of the alloys at the beach corrosion testing site, and the expected rate of corrosion as predicted based on the polarization resistance values obtained. The data indicate that electrochemical impedance spectroscopy can be used to predict the corrosion performance of metal alloys.

  18. Ocorrência de fungos filamentosos termo-resistentes em polpa de tomate envasada assepticamente Occurrence of heat resistant molds in tomato pulp packed aseptically

    Directory of Open Access Journals (Sweden)

    Flávio BAGLIONI

    1999-05-01

    Full Text Available Este trabalho teve como objetivo principal determinar a ocorrência de fungos filamentosos termo-resistentes durante o processamento asséptico de polpa de tomate (8° BRIX. Durante o período de safra de tomate foram feitas amostragens em 9 lotes (3 no início, 3 no pico e 3 em fim de safra e no período de entresafra em 5 lotes. Foi feita a enumeração de fungos termo-resistentes nas amostras coletadas durante as diferentes etapas do processo asséptico de cada lote. Foram obtidas contagens médias relativamente baixas, variando entre This work aimed at determining the occurrence of heat resistant molds during the aseptic processing of tomato pulp (8° BRIX. During tomato harvest, 9 lots were sampled (3 at the beginning, 3 at the apex and 3 at the end of harvest and other 5 lots were sampled between harvest. For each lot, the enumeration of heat resistant molds was carried out in samples collected during the aseptic process. The mean count of heat resistant molds was relatively low, ranging from <1 to 8CFU/100mL of sample. The higher counts were observed in the raw material and the pre-wash and transportation water. Fifty strains of heat resistant molds detected in the enumeration procedure were isolated, codified and stocked. One-month-old spores of each isolate were submitted to different heat shocks to select the most heat resistant mold. The most heat resistant isolated strain (survived 100° C/25 minutes was identified as Neosartorya fischeri.

  19. Magnesium Cermets and Magnesium-Beryllium Alloys

    International Nuclear Information System (INIS)

    The paper describes some results of work on the development of magnesium-magnesium oxide cermets and of super heat-resistant magnesiumberyllium alloys produced by powder metallurgical methods. The introduction of even a minute quantity of finely dispersed magnesium oxide into magnesium results in a strengthening of the material, the degree of which increases with increased magnesium oxide concentration, although variation of this concentration within the limits of 0.3 to 5 wt.% has a comparatively slight effect on the corresponding variation in the short-term strength over the whole range of temperatures investigated. At 20oC, in the case of the cermets, ?? = 28 to 31 kg/mm2 and ? = 3 .5 to 4.5%; at 500oC ?? = 2.6 to 3.2 kg/mm2 and ? =30 to 40%. The positive effect of the finely dispersed oxide phase is particularly evident in protracted tests. For magnesium cermets, ? (300)/100 = 2.2 kg/mm2. Characteristic of the mixtures is the high thermal stability of the strength properties, linked chiefly with the thermodynamic stability of the strength-giving oxide phase in the metal matrix. The use of powder metallurgical methods has yielded super heat-resistant magnesium-beryllium alloys containing heightened concentrations of beryllium (PMB alloys). In their strength characteristics PMB alloys are close to Mg-MgO cermets, but the magnesium-beryllium alloys have a degree and duration of resistave a degree and duration of resistance to high temperature oxidation which exceeds the corresponding qualities of the magnesium alloys at present known. Thus, in air of 580oC, PMB alloys with 2 to 5% beryllium maintain a high resistance to oxidation for a period of over 12000 to 14000 h. This long-term heat resistance is chiefly a result of the amount of beryllium in the alloy, and increases with increasing beryllium content. PMB alloys are also marked by high resistance to short bursts of overheating. Magnesium cermets and magnesium-beryllium alloys, with their enhanced high-temperature stability, are capable of finding extensive application in various branches of technology. (author)

  20. Properties of Al-Cr-Zr alloys prepared by the melt extraction in electromagnetic field

    International Nuclear Information System (INIS)

    Properties of Al-2.5Cr-2.57Zr alloys prepared by melt extraction in electromagnetic field are considered. The method provides homogenezation, maintaining of the required temperature and hydrodynamical parameters of the melt and influence on the melt crystallization. Some semifinished products fabricated by moulding of rapidly solidificated particles have properties exceeding substantially the properties achieved using conventional AK4-1 and 1201 heat resistant alloys. 5 refs.3 figs.; 4 tabs

  1. Degradation of structure and properties of heat-resistant boiler steels during operation of power equipment

    International Nuclear Information System (INIS)

    Investigation results are reported on changes in microstructure and mechanical properties of widely used in power industry low-carbon and low-alloy steels (10K, 15K, 12Kh1MF) after their long-term operation as structural components of boilers and pipelines. Steel 19K is applied for steam-water pipelines, steel 15K - for boiler components, steel 12Kh1MF - for superheaters. It is stated that no significant decrease of service properties of the materials is revealed after 5 years operation of power equipment of thermal plants under standard conditions. Steel 12Kh1MF is shown to experience thermal embrittlement on operation: solid solution decomposition and alloying element transfer into carbide precipitated, this results in a decrease of material plasticity but the strength even increase

  2. Kinetics of chromium evaporation from heat-resisting steel under reduced pressure

    Directory of Open Access Journals (Sweden)

    C. Kolmasiak

    2012-07-01

    Full Text Available This paper describes a kinetic analysis of the process of chromium evaporation from ferrous alloys smelted under reduced pressure. The study discussed comprised determination of the liquid phase mass transfer coefficient as well as the value of the constant evaporation rate. By applying these values as well as the values of the overall mass transfer coefficient estimated based on the relevant experimental data, the fractions of resistance of the individual process stages were established.

  3. Summary of studies on hot corrosion of iron-based alloys by sodium sulfate in O2/SO2/SO3 environment

    OpenAIRE

    Zhang, Yunshu; Wu, Weitao

    1993-01-01

    Iron base heat-resistant alloys are widely used in high temperature environments, especially in civil and industrial boilers and other combustors. This type of alloys was found to undergo hot corrosion when covered with a sulfate deposit. Recent studies of sulfate-deposit-induced hot corrosion of iron-base alloys are selectively reviewed in this paper. Emphasis is placed on studies of the hot corrosion occurring at relatively low temperatures, concerning the thermodynamics of the formation of...

  4. Microstructure and magnetic properties of mechanically alloyed FeSiBAlNi (Nb) high entropy alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jian [School of Materials Science and Engineering, University of Jinan, No. 336, West Road of Nan Xinzhuang, Jinan 250022 (China); Shandong Provincial Key Laboratory of Preparation and Measurement of Building Materials, University of Jinan, No. 336, West Road of Nan Xinzhuang, Jinan 250022 (China); Zheng, Zhou; Xu, Jing [School of Materials Science and Engineering, University of Jinan, No. 336, West Road of Nan Xinzhuang, Jinan 250022 (China); Wang, Yan, E-mail: mse_wangy@ujn.edu.cn [School of Materials Science and Engineering, University of Jinan, No. 336, West Road of Nan Xinzhuang, Jinan 250022 (China); Shandong Provincial Key Laboratory of Preparation and Measurement of Building Materials, University of Jinan, No. 336, West Road of Nan Xinzhuang, Jinan 250022 (China)

    2014-04-15

    In this paper, the effects of milling duration and composition on the microstructure and magnetic properties of equi-atomic FeSiBAlNi and FeSiBAlNiNb high entropy alloys during mechanical alloying have been investigated using X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, transmission electron microscopy and alternating gradient magnetometry. The amorphous high entropy alloys have been successfully fabricated using the mechanical alloying method. The results show that the Nb addition prolongs the milling time for the formation of the fully FeSiBAlNi amorphous phase and decreases the glass forming ability. However, FeSiBAlNiNb amorphous high entropy alloy has the higher thermal stability and heat resisting properties. Moreover, the as-milled FeSiBAlNi(Nb) powders are soft-magnetic materials indicated by their low coercivity. The saturation magnetization of the as-milled FeSiBAlNi(Nb) powders decreases with prolonging of the milling time and shows the lowest value when the amorphous high entropy alloys are formed. It suggests that the as-milled products with solid solution phases show the better soft-magnetic properties than those with fully amorphous phases. The Nb addition does not improve the soft-magnetic properties of the FeSiBAlNi high entropy alloys. Rather, both amorphous high entropy alloys have similar soft-magnetic properties after a long milling time. - Highlights: ?FeSiBAlNi(Nb) amorphous high entropy alloys (HEAs) were fabricated by the MA method. ?Nb decreases GFA and enhances thermal stability and heat resisting properties. ?FeSiBAlNi HEA shows the better soft magnetism than that of the FeSiBAlNiNb HEA. ?FeSiBAlNi(Nb) HEAs show the better soft magnetism than that of their amorphous HEAs. ?The existent mode of solid solution phases of the HEAs affects soft magnetism.

  5. Microstructure and magnetic properties of mechanically alloyed FeSiBAlNi (Nb) high entropy alloys

    International Nuclear Information System (INIS)

    In this paper, the effects of milling duration and composition on the microstructure and magnetic properties of equi-atomic FeSiBAlNi and FeSiBAlNiNb high entropy alloys during mechanical alloying have been investigated using X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, transmission electron microscopy and alternating gradient magnetometry. The amorphous high entropy alloys have been successfully fabricated using the mechanical alloying method. The results show that the Nb addition prolongs the milling time for the formation of the fully FeSiBAlNi amorphous phase and decreases the glass forming ability. However, FeSiBAlNiNb amorphous high entropy alloy has the higher thermal stability and heat resisting properties. Moreover, the as-milled FeSiBAlNi(Nb) powders are soft-magnetic materials indicated by their low coercivity. The saturation magnetization of the as-milled FeSiBAlNi(Nb) powders decreases with prolonging of the milling time and shows the lowest value when the amorphous high entropy alloys are formed. It suggests that the as-milled products with solid solution phases show the better soft-magnetic properties than those with fully amorphous phases. The Nb addition does not improve the soft-magnetic properties of the FeSiBAlNi high entropy alloys. Rather, both amorphous high entropy alloys have similar soft-magnetic properties after a long milling time. - Highlights: ?FeSiBAlNi(Nb) amorphous high entropy alloys (HEAs) were fabricated by the MA method. ?Nb decreases GFA and enhances thermal stability and heat resisting properties. ?FeSiBAlNi HEA shows the better soft magnetism than that of the FeSiBAlNiNb HEA. ?FeSiBAlNi(Nb) HEAs show the better soft magnetism than that of their amorphous HEAs. ?The existent mode of solid solution phases of the HEAs affects soft magnetism

  6. Effects of yttrium on microstructure and mechanical properties of Mg-6Al magnesium alloy

    OpenAIRE

    Ren Wenliang; Li Quan'an; Li Jianhong

    2010-01-01

    Since Y has a great solid solubility in magnesium alloys, it helps enhancing the heat-resistant property of magnesium alloys. The effects of Y on microstructures and mechanical properties of Mg-6Al alloy have been studied in this work. The results show that Y addition refines grains of Mg-6Al alloy, and reduces the amount of the Mg17Al12 phase. At the same time, the high melting-point Al2Y phase particles are formed. According to the mathematical model of the two-dimensional lattice misfit pr...

  7. The effect of alloying on the ordering processes in near-alpha titanium alloys

    International Nuclear Information System (INIS)

    The substructure of near-alpha Ti–Al–Sn–Zr–Mo–Si alloys containing up to 12.5 at% aluminum was studied by transmission electron microscopy (TEM). It was shown that long-range order sections are formed at aging temperatures up to 500 °C in alloys, high in aluminum, and the ordered phase is formed by the nucleation and growth mechanism at 700 °C aging temperatures. Causes of changing the phase transformation mechanism have been discussed, and the relationship between the structure and properties of alloys, depending on modes of heat treatment has been analyzed. Also the influence of aluminides and silicides precipitation on the mechanical alloy properties after aging was examined. It was shown that the aluminide formation led to a slight hardening and a significant viscosity decrease. The silicide particles formation reduced the heat resistance properties, due to the depletion of the solid solution by silicon

  8. Wrought stainless steel compositions having engineered microstructures for improved heat resistance

    Science.gov (United States)

    Maziasz, Philip J [Oak Ridge, TN; Swindeman, Robert W [Oak Ridge, TN; Pint, Bruce A [Knoxville, TN; Santella, Michael L [Knoxville, TN; More, Karren L [Knoxville, TN

    2007-08-21

    A wrought stainless steel alloy composition includes 12% to 25% Cr, 8% to 25% Ni, 0.05% to 1% Nb, 0.05% to 10% Mn, 0.02% to 0.15% C, 0.02% to 0.5% N, with the balance iron, the composition having the capability of developing an engineered microstructure at a temperature above 550.degree. C. The engineered microstructure includes an austenite matrix having therein a dispersion of intragranular NbC precipitates in a concentration in the range of 10.sup.10 to 10.sup.17 precipitates per cm.sup.3.

  9. Response Surface Design Model to Predict Surface Roughness when Machining Hastelloy C-2000 using Uncoated Carbide Insert

    International Nuclear Information System (INIS)

    This paper presents to develop of the response surface design model to predict the surface roughness for end-milling operation of Hastelloy C-2000 using uncoated carbide insert. Mathematical model is developed to study the effect of three input cutting parameters includes the feed rate, axial depth of cut and cutting speed. Design of experiments (DOE) was implemented with the aid of the statistical software package. Analysis of variance (ANOVA) has been performed to verify the fit and adequacy of the developed mathematical model. The result shows that the feed rate gave the more effect on the both prediction values of Ra compared to the cutting speed and axial depth of cut. SEM and EDX analyses were performed in different cutting conditions. It can be concluded that the feed rate and cutting force give the higher impact to influence the machining characteristics of surface roughness. Thus, the optimizing the cutting conditions are essential in order to improve the surface roughness in machining of Hastlelloy C-2000.

  10. Electromagnetic property of SiO2-coated carbonyl iron/polyimide composites as heat resistant microwave absorbing materials

    Science.gov (United States)

    Wang, Hongyu; Zhu, Dongmei; Zhou, Wancheng; Luo, Fa

    2015-02-01

    Heat resistant microwave absorbing materials were prepared by compression molding method, using polyimide resin as matrix and SiO2 coated carbonyl iron (CI) as filler. The SiO2 coated CI particles were prepared by Stober process. The microwave absorbing properties and the effect of heat treatment on the electromagnetic properties of SiO2 coated CI/polyimide composites were investigated. When the content of SiO2 coated CI is 60 wt%, the value of minimum reflection loss decreases from -25 dB to -33 dB with the thickness increases from 1.5 mm to 2.1 mm. According to the thermal-gravimetric analyses (TGA) curves, the polyimide matrix can be used at 300 °C for long time. The complex permittivity of the composites slightly increases while the complex permeability almost keeps constant after heat treatment at 300 °C for 10 h, which indicating that the composites can be used at elevated temperature as microwave absorbing materials at the same time have good heat resistance and microwave absorption.

  11. Microstructural analysis as the indicator for suitability of weld repairing of the heat resistant Cr - Ni steel

    International Nuclear Information System (INIS)

    Metallurgical evaluation was performed on a fractured column tube of the reformer furnace in an ammonia plant. The tubes were manufactured from centrifugally cast heat resistant steel HK 40. Optical and scanning electron microscope (SEM) were used for microstructural and fracture analysis. For composition determination of the micro constituents energy dispersive X ray spectroscopy (EDS) was used. To evaluate mechanical properties, hardness and microhardness measurements were performed. Investigations based on the microstructural features with the idea to indicate suitability of weld repair of the column were performed in this study. It was observed that the crack initiation, caused by oxidation/corrosion and thermal stresses induced by temperature gradient, appeared in the inner side of the tube wall and propagation occurred along grain boundaries. The results clearly showed the presence of an irregular microstructure which contributed to crack propagation through the tube wall. An occurrence of precipitated needle-shaped carbides/carbonitrides and brittle s phase was also identified in the microstructure. Results of the microstructural and fracture analysis clearly indicate that reformer furnace columns made of heat resistant steel HK 40 were unsuitable for weld repair. (Author)

  12. Fiber reinforced superalloys, ceramics, and refractory metals, and directionally solidified eutectics (heat-resistant composites)

    International Nuclear Information System (INIS)

    High-temperature composites have been shown to have excellent elevated-temperature tensile and stress-rupture strengths and specific strengths. Tungsten alloy fiber reinforced superalloys have been demonstrated to have stress rupture strengths at 20000F superior to superalloys and sufficient impact resistance for gas turbines. Recently developed tungsten alloy fibers should permit production of composites with use-temperatures (gas turbine blades, vanes) as high as 24000F. Their main problem is associated with the direction and perfection of growth of strong whiskers or lamina in irregularly shaped components. Artificially made whisker composites are believed to warrant serious consideration. Use-temperatures of refractory metal matrix composites can be as much as 25000F for Nb matrix composites and over 30000F for W matrix composites. Ceramic matrix composites with use-temperatures ranging from 18000F to over 30000F are possibilities. Stationary, large, turbines for power generation may make use of refractory fiber/superalloy matrix, ceramic matrix, and coated refractory matrix composites. Such an application may capitalize on the high-temperature strength and high use-temperatures of the composites, which, in turn, will enhance engine performance. (127 references, 62 fig, 22 tables) (U.S.)

  13. Development of high-chromium ferritic clad heat exchanger tubing. [Sanicro 28, Carpenter 20 Mo-76, Al-6XN, Monit, SEA-CURE, Inconel 625, Hastelloy C-276, Hastelloy G-3

    Energy Technology Data Exchange (ETDEWEB)

    Cox, T.B.; Sponseller, D.L.

    1986-05-01

    High chromium, corrosion resistant alloys are required to withstand the high temperatures and corrosive environment of coal gasification plants such as the Cool Water facility. The production of tubing for heat exchangers from high alloy materials is a priority goal of the EPRI gasification materials program. Because many high chromium alloys are very expensive and have little elevated temperature strength, it would be advantageous to clad the outside surface of low alloy, elevated temperature steel tubes with the corrosion resistant alloy and rely on the low alloy steel for structural strength. Evaluation of commercial alloys for possible use as monolithic or coextruded tubes identified four compositions suitable for evaporator tube applications and four compositions for superheater applications. In addition, a series of alloys containing 30% chromium were evaluated for their ability to be coextruded with 1.25Cr-0.5Mo steel, undergo welding and resist gasification corrosion. An alloy, nominally 30Cr-2Ni-2Mo, was successfully coextruded to various tubing sizes and provided to EPRI for testing in the Cool Water gasification plant. 18 refs., 28 figs., 28 tabs.

  14. Creep-rupture behaviour of four high temperature alloy weldments at 850 and 950 deg C

    International Nuclear Information System (INIS)

    Creep tests were conducted on weldments made with Hastelloy X (matching filler), Nimonic 86 (Inconel 112 filler), Inconel 617 (Inconel 112 filler) and Alloy 800H (Thermanit 21/33 filler) at 850 and 950 deg C in air and in controlled impurity helium. Plain and notched samples were used, the notch being in the weld metal. At 850 deg C, the welds achieved rupture strengths close to those expected for the parent materials. At 950 deg C, however, shortfalls in expected strength were found for the Hastelloy X and Inconel 617 welds. In Hastelloy X, welding reduced the rupture strength of the parent material but in the Inconel 617 weld, failure reflected inadequate strength of the filler. Various failure types were noted but failure often occurred near a structural or strength transition. In particular, a heat affected zone type of failure was promoted by a combination of strong filler and weaker parent. Notched samples achieved or exceeded rupture lives of their companion plain samples. Environmental effects were small, producing no consistent effect on rupture life although oxidation rates and surface crack nucleation were greater in air. Oxidation resistance of Thermanit 21/33 in air at 950 deg C was poor. (author)

  15. Solute Transport Proteins and the Outer Membrane Protein NmpC Contribute to Heat Resistance of Escherichia coli AW1.7?

    OpenAIRE

    Ruan, Lifang; Pleitner, Aaron; Gänzle, Michael G; McMullen, Lynn M.

    2011-01-01

    This study aimed to elucidate determinants of heat resistance in Escherichia coli by comparing the composition of membrane lipids, as well as gene expression, in heat-resistant E. coli AW1.7 and heat-sensitive E. coli GGG10 with or without heat shock. The survival of E. coli AW1.7 at late exponential phase was 100-fold higher than that of E. coli GGG10 after incubation at 60°C for 15 min. The cytoplasmic membrane of E. coli AW1.7 contained a higher proportion of saturated and cyclopropane fa...

  16. Preparation and characterization of Fe–Al intermetallic layer on the surface of T91 heat-resistant steel

    International Nuclear Information System (INIS)

    A Fe–Al intermetallic layer was formed on the surface of T91 heat-resistant steel by a molten aluminum hot-dipping and heat diffusion treatment. It is shown that the layer was composed of Al, FeAl3 and Fe2Al5 phases in the as-dipped state while only Fe3Al phase retained after the heat treatment. The intermetallic layer exhibited typical columnar grain structure after the heat treatment, and the thickness of aluminizing layer was increased from 55 ?m at 760 °C to around 100 ?m at 1050 °C heat treatment. Such a phase composition and grain morphology are favorable for the oxidation and corrosion resistance of T91 steel

  17. Effect of thymol in heating and recovery media on the isothermal and non-isothermal heat resistance of Bacillus spores.

    Science.gov (United States)

    Esteban, Maria-Dolores; Conesa, Raquel; Huertas, Juan-Pablo; Palop, Alfredo

    2015-06-01

    Members of the genus Bacillus include important food-borne pathogen and spoilage microorganisms for food industry. Essential oils are natural products extracted from herbs and spices, which can be used as natural preservatives in many foods because of their antibacterial, antifungal, antioxidant and anti-carcinogenic properties. The aim of this research was to explore the effect of the addition of different concentrations of thymol to the heating and recovery media on the thermal resistance of spores of Bacillus cereus, Bacillus licheniformis and Bacillus subtilis at different temperatures. While the heat resistance was hardly reduced when thymol was present in the heating medium, the effect in the recovery medium was greater, reducing the D100 °C values down to one third for B. subtilis and B. cereus when 0.5 mM thymol was added. This effect was dose dependent and was also observed at other heating temperatures. PMID:25790989

  18. Effect of tempering treatment before aging on the microstructure and mechanical properties of ferritic heat-resistant steels

    International Nuclear Information System (INIS)

    This study investigated the effect of the tempering before aging on the precipitation of Laves phase and mechanical properties of 10Cr-6W and 10Cr-6W-3Co ferritic heat-resistant steels. Laves phase was precipitated by aging, which increased tensile strength but decreased elongation and impact value. Toughness was rapidly decreased by the presence of the very fine disk-like Laves phase precipitated at early aging stage. Strength and impact value were decreased by tempering treatment and that is due to the increase of the particle number per unite area and to larger particle size of Laves phase. Laves phase increased by adding Co, and consequently strength was increased and elongation and toughness were decreased

  19. Study on high temperature design methodology of heat-resistant materials for GEN-IV systems

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Woo Seog; Kim, D. W.; Kim, S. H.; Kim, W. G.; Kim, J. H.; Park, D. G.; Yoon, J. H.; Lee, H. Y.; Hing, J. H

    2005-08-15

    Analysis of the existing high temperature design and assessment codes such as US(ASME-NH,Draft Code Case for Alloy 617), France(RCC-MR), UK(R5), Japan(BDS/DDS/FDS) for Gen IV reactor structure has been carried out. In addition the scope and fields for research and development is needed in the future have been defined. For assessing the high temperature creep cracks, time dependent fracture mechanics (TDFM) parameters of the C and Ct were analyzed. The creep propagation data were obtained from the creep crack growth tests for type 316LN stainless steels, and creep crack growth testing machine for Gen-IV system up to 950 .deg. C was set up. Damage mechanism and causes for creep-fatigue were investigated. The difference between prediction creep-fatigue life and experimental life were investigated. Material properties for analysis creep-fatigue damage were recommended. The assessment procedure (Draft) on creep-fatigue crack initiation has been developed based on the technical appendix A16 of French RCC-MR code. Ultrasonic wave signal against creep ruptured specimens of type 316LN stainless steel was obtained. It was identified that creep damage can be evaluated by ultrasonic method. The NDT techniques evaluated include Barkhausen noise, magnetic hysteresis parameters, positron annihilation, X-ray diffraction and small angle neutron scattering. Experimental procedure and evaluation method of material integrity were developed through the fracture toughness test of Cr-Mo steel.

  20. Study on high temperature design methodology of heat-resistant materials for GEN-IV systems

    International Nuclear Information System (INIS)

    Analysis of the existing high temperature design and assessment codes such as US(ASME-NH,Draft Code Case for Alloy 617), France(RCC-MR), UK(R5), Japan(BDS/DDS/FDS) for Gen IV reactor structure has been carried out. In addition the scope and fields for research and development is needed in the future have been defined. For assessing the high temperature creep cracks, time dependent fracture mechanics (TDFM) parameters of the C and Ct were analyzed. The creep propagation data were obtained from the creep crack growth tests for type 316LN stainless steels, and creep crack growth testing machine for Gen-IV system up to 950 .deg. C was set up. Damage mechanism and causes for creep-fatigue were investigated. The difference between prediction creep-fatigue life and experimental life were investigated. Material properties for analysis creep-fatigue damage were recommended. The assessment procedure (Draft) on creep-fatigue crack initiation has been developed based on the technical appendix A16 of French RCC-MR code. Ultrasonic wave signal against creep ruptured specimens of type 316LN stainless steel was obtained. It was identified that creep damage can be evaluated by ultrasonic method. The NDT techniques evaluated include Barkhausen noise, magnetic hysteresis parameters, positron annihilation, X-ray diffraction and small angle neutron scattering. Experimental procedure and evaluation method of material integrity were developed through the fracture toughness test of Cr-Mo steel

  1. Acoustical properties of Ni3Al single crystals alloyed with cobalt and niobium

    International Nuclear Information System (INIS)

    A study of acoustic properties are accomplished for cobalt or niobium alloyed Ni3Al intermetallic single crystals used as structural heat resistant materials, in particular, for turbine blades. Measurements are made for elastic wave velocities which serve as a basis to determine elastic moduli, a factor of elastic anisotropy, Debye temperature values. The alloying elements are found to affect Debye temperature variously: cobalt decreases and niobium increases its value. In cobalt alloyed Ni3Al single crystals an anomalously high factor of anisotropy is revealed, this is associated with structural nonhomogeneity (subgrain structure) providing an elevated attenuation of ultrasonic waves in the material

  2. Mechanical properties of welds in commercial alloys for high-temperature gas-cooled reactor components

    International Nuclear Information System (INIS)

    Weld properties of Hastelloy-X, Incoloy alloy 800H (with and without Inconel-82 cladding), and 2 1/4 Cr-1 Mo are being studied to provide design data to support the development of steam generator, core auxiliary heat exchanger, and metallic thermal barrier components of the high-temperature gas-cooled reactor (HTGR) steam cycle/cogeneration plant. Tests performed include elevated-temperature creep rupture tests and tensile tests. So far, data from the literature and from relatively short-term tests at GA Technologies Inc. indicate that the weldments are satisfactory for HTGR application

  3. Thermodiffusion Mo-B-Si coating on VN-3 niobium alloy

    International Nuclear Information System (INIS)

    Protective properties of complex Mo-B-Si-coating on niobium alloy VN-3 (4.7 mass.% Mo, 1.1 mass.% Zr, 0.1 mass.% C) have been studied. It is established, that the complex Mo-B-Si-coating ensures protection from oxidation of niobium alloys in the temperature range of 800-1200 degC for 1000-1500 hr, at 1600 degC - for 10 hr. High heat resistance of Mo-B-Si - coating at 800-1200 degC is determined by the presence of amorphous film of SiO?2 over the layer MoSi?2 and barrier boride layer on the boundary with the metal protected; decrease in the coating heat resistance at 1600 degC is related to the destruction of boride layer, decomposition of MoSi?2 for lower cilicides and loosening of SiO?2 film

  4. Microstructural analysis as the indicator for suitability of weld repairing of the heat resistant Cr - Ni steel

    Directory of Open Access Journals (Sweden)

    Odanovi?, Z.

    2010-08-01

    Full Text Available Metallurgical evaluation was performed on a fractured column tube of the reformer furnace in an ammonia plant. The tubes were manufactured from centrifugally cast heat resistant steel HK 40. Optical and scanning electron microscope (SEM were used for microstructural and fracture analysis. For composition determination of the microconstituents energy dispersive X ray spectroscopy (EDS was used. To evaluate mechanical properties, hardness and microhardness measurements were performed. Investigations based on the microstructural features with the idea to indicate suitability of weld repair of the column were performed in this study. It was observed that the crack initiation, caused by oxidation/corrosion and thermal stresses induced by temperature gradient, appeared in the inner side of the tube wall and propagation occurred along grain boundaries. The results clearly showed the presence of an irregular microstructure which contributed to crack propagation through the tube wall. An occurrence of precipitated needle-shaped carbides/carbonitrides and brittle ? phase was also identified in the microstructure. Results of the microstructural and fracture analysis clearly indicate that reformer furnace columns made of heat resistant steel HK 40 were unsuitable for weld repair.

    La evaluación metalúrgica se realizó en un tubo de columna con fracturas, que es parte del horno reformador en una planta de amoníaco. Estos tubos son fundidos centrífugamente y fabricados en acero resistente al calor, de tipo HK- 40. Para el análisis microestructural de la fractura se ha utilizado microscopía óptica y electrónica de barrido (SEM. La composición de los micro-constituyentes se determinó por espectrometría de rayos X de energía dispersiva (EDS. Las propiedades mecánicas se evaluaron mediante mediciones de microdureza Vickers. Las investigaciones en este estudio se han llevado a cabo con el fin de demostrar la idoneidad de reparación por soldadura de columnas en base a sus características micro-estructurales. Se ha observado que el inicio de la rotura, causada por el efecto de la oxidación/corrosión y el choque térmico ocasionado por el gradiente de temperatura, aparece en la pared interna del tubo y se propaga a lo largo de los bordes de grano. Los resultados demuestran la presencia de una microestructura irregular que contribuyó a la propagación de la rotura a lo largo de la pared del tubo. En la microestructura también se ha registrado la formación da la precipitación de fases de carburo/carbón nitrito que aparecen en forma de agujas y fase ? frágil. Con base en los resultados obtenidos, se puede concluir que la microestructura investigada no es idónea para aplicar la reparación por soldadura.

  5. Corrosion behavior of C-276 alloy in supercritical water at 650 degree C/25 MPa

    International Nuclear Information System (INIS)

    The corrosion behavior of nickel-base alloy Hastelloy C-276 was investigated in supercritical water (SCW) at 650 degree C/25 MPa. SEM, EDS, GIXRD and XPS were used to analyze the corrosion morphology, structure and element distribution of oxide film. The results show that the corrosion process of C-276 alloy at 650 degree C/25 MPa in SCW is mainly dissolution of Ni. Since it can not form a uniform and complete oxide film, the alloy in SCW is not well placed to corrosion resistance. The dual-layer oxide film structure which is formed on C-276 is rich in Cr but poor in Ni, Mo. The outer layer consisting of loose and large grains Ni(OH)2 and NiO agrees with dissolution and precipitation mechanism, while the growth of the Cr2O3 inner layer is the result of water through the porous oxides. (authors)

  6. ZrO2-base fritted refractory material for lining induction precision alloy furnaces

    International Nuclear Information System (INIS)

    ZrO2-base refractory was utilized for fabrication of fritted crucibles for precision alloy fusion. The fitness of the material was estimated from the data on the degree of the metal penetration into the wall of the refractory crucible and from the wetting angle of the fritted refractory samples. An elevated heat resistance of the lining and a high quality of the synthesized metal are pointed out

  7. Structural thermal stability of Ni3Al-base alloy and its use for blades of small-size gas-turbine engine

    International Nuclear Information System (INIS)

    The comparative evaluation of stability of the working blades structures of the TVD-20 engine turbine, produced from the experimental alloy VKNA-4UMono and the serial alloy ZhS64 is carried out after 4800 operating cycles on the engine. It is shown that replacement of the industrial serial nickel alloys of the ZhS64-type by the intermetallide alloy VKNA-4UMono provides for the possibility of increasing the permissible operating temperatures on the working and nozzle blades of the aviation gas-turbine engines by 50-100 Deg C, decreasing their mass, improving their heat resistance and increasing their service life by 2-3 times

  8. Study of temperature effect on the physical properties of ilmenite-serpentine heat resistant concrete radiation shields

    International Nuclear Information System (INIS)

    A series of experimental studies have been carried out to determine the change in unit weigh, compressive strength, water content and neutron macroscopic cross section of a new type of concrete shields made from egyptian ilmenite and serpentine ores when heated for long period at temperatures up to 600 degree C. Results show that the unit weight of the cure concrete has a value of 2.98 Ton/M3 and decreases with increasing temperature, while the compressive strength reaches a maximum value of 19 Ton/M2 at 100 degree C. The differential thermal analysis (D.T.A.) of this concrete shows three endothermic peaks at 100 degree C, 48 degree C and 740 degree C. Also, the thermogravimetry analysis (T.G.A.) shows that the cure concrete retains about 11% water content of the total sample weigh and still retains 4.5% of its initial value when heated for long period at 600 degree C. Results also show that the neutron macroscopic cross section (for neutrons of energies < 1 MeV) of the ilmenite-serpentine heat resistant concrete decreases to 18.6% of its initial value after heating to 600 degree C

  9. Preparation and characterization of the heat-resistant UV curable waterborne polyurethane coating modified by bisphenol A

    Directory of Open Access Journals (Sweden)

    2010-11-01

    Full Text Available In this study, the modified ultraviolet (UV curable waterborne polyurethane was obtained from isophorone diisocyanate (IPDI, polyethylene glycol (PEG, MW=600, ?,?-dimethylol propionic acid (DMPA, hydroxyethyl acrylate (HEA and bisphenol A. The rigid moiety was introduced into the main chain of polyurethane to improve its heat-resistance. The copolymer structure was confirmed by Fourier transform infrared spectroscopy (FT-IR. Thermal property and UV curable behavior of the coatings were investigated. The glass transition temperature (Tg of the modified film was determined by differential scanning calorimetry (DSC. Thermal gravimetric analysis (TGA was employed to investigate the thermal stability of the modified film. The results show that the average particle diameters increased from 69.25 to 95.12 µm as the content of bisphenol A increased from 0.00 to 9.25%. The optimum bisphenol A dosage was 7.23% (wt%, the Tg of the modified film increased by 7.07°C and 5% weight-loss temperature (233°C increased by 14°C. The optimum irradiation time was 10–20 minutes after the coatings being painted on an armor plate at room temperature and initiator dosage was 5% (wt% of the latex.

  10. Effect of normalizing temperature on the strength of 9Cr–3W–3Co martensitic heat resistant steel

    International Nuclear Information System (INIS)

    Microstructure and room temperature strength of 9Cr–3W–3Co martensitic heat resistant steel after normalizing at 900–1200 °C for 1 h and then tempering at 750 °C for 1 h have been experimentally investigated using optical microscope (OM), field emission scanning electron microscope (FESEM), electron back-scattered diffraction (EBSD), field emission transmission electron microscope (FETEM) and tensile tests. The results show that with increasing normalizing temperature, the strength of the 9Cr–3W–3Co steel increases from 900 °C to 1000 °C, then keeps almost the same from 1000 °C to 1100 °C and finally increases again from 1100 °C to 1200 °C. The change in the room temperature strength can mainly be attributed to the change in precipitation strengthening. The size and the amount of particles after tempering are mainly due to the re-dissolution of particles during normalization. The higher the normalizing temperature is, the more the coarse particles formed during manufacturing will be re-dissolved, and then the larger the amount of fine particles precipitated during tempering is

  11. Effect of tempering temperature on the toughness of 9Cr–3W–3Co martensitic heat resistant steel

    International Nuclear Information System (INIS)

    Highlights: • Toughness of 9Cr–3W–3Co steel increases with increasing tempering temperature. • Toughness is influenced by hardness of base metal and length of crack propagation path. • Hardness of base metal is influenced by dislocation density and degree of supersaturation of the interstitial atoms. • Length of crack propagation path is influenced by length of the large angle boundaries. - Abstract: Effect of tempering temperature on the toughness of 9Cr–3W–3Co martensitic heat resistant steel was studied on the basis of the microstructures after normalized at 1100 °C for 1 h and then tempered at 740–780 °C for 3 h. With increasing tempering temperature from 740 °C to 780 °C, the absorbed energy of the 9Cr–3W–3Co steel increased greatly from 26 J to 115 J. The change of the toughness with increasing tempering temperature was attributed to the softening of the base metal and the increase of the crack propagation path. The softening of the base metal was caused by the decrease of the dislocation density and the supersaturation of the interstitial atoms. The reason for the increase of the crack propagation path was that the length of the large angle boundaries increased and then the propagation direction of the cleavage crack was deflected more frequently

  12. Development of cold isostatic pressing graphite module for a heat-resistant lower hybrid current drive antenna

    International Nuclear Information System (INIS)

    Development of a plasma facing module using Cold Isostatic Pressing Graphite (CIPG) was successfully achieved for use in driving a heat-resistant Lower Hybrid Current Drive (LHCD) antenna. A thin stainless film (10 ?m), a molybdenum film (10 ?m), and a copper film (50 ?m) were overlaid on the CIPG materials, the CIPG surfaces were successfully coated with the Cu-layer by diffusion bonding method. This module whose length is 206 mm, has four waveguides, and a water cooling channel. High rf-power long pulse operations with water cooling were successfully tested up to 250 kW (125 MW/m2)/700 s, a stationary temperature and vacuum pressure was performed. But the maximum rf transmission power was limited to 47 MW/m2 for a plasma facing module using Carbon Fiber Composite (CFC) due to poor Cu-plating, a power density large by more than a factor 2.5 was achieved with the CIPG module. The rf power density which meets the requirement of the rf electric field of 5 kV/cm for a design of the LHCD antenna in International Thermonuclear Experimental Reactor (ITER) was successfully performed

  13. Elevated levels of 70,000 dalton heat shock protein in transiently thermotolerant Chinese hamster fibroblasts and in their stable heat resistant variants

    International Nuclear Information System (INIS)

    The function of one or more shock proteins (HSPs) may be to confer protection of cells against thermal damage. The quantitative relationship between heat sensitivity and concentration of several HSPs was examined in thermotolerant Chinese hamster HA-1 cells and in their heat-resistant variants. Low molecular weight HSPs (22-27 kd) showed no correlation with cell survival. The best correlation was found between concentration of 70 kd HSP and the logarithm of cell survival. There was no difference between the HSP 70 induced by heat shock and that present in a constitutive form. The 70 kd HSP may actually confer heat resistance on cells, but in any case HSP 70 appeared to be the best predictor of heat response

  14. Cloning, sequencing, and viscometric adhesion analysis of heat-resistant agglutinin 1, an integral membrane hemagglutinin from Escherichia coli O9:H10:K99.

    OpenAIRE

    Lutwyche, P; Rupps, R; Cavanagh, J; Warren, R. A.; Brooks, D E

    1994-01-01

    The gene encoding a mannose-resistant hemagglutinating protein was cloned from Escherichia coli O9:H10:K99. The hemagglutinin is different from two other mannose-resistant hemagglutinins in this strain, K99 and F41. The agglutinin, named heat-resistant agglutinin 1 (HRA1) since heating to 70 degrees C does not destroy its aggregative properties, strongly agglutinates human, pig, and dog erythrocytes, shows little or no affinity towards cow and chicken erythrocytes, but agglutinates human colo...

  15. PREDICTIVE MODEL FOR THE COMBINED EFFECT OF TEMPERATURE, SODIUM LACTATE, AND SODIUM DIACETATE ON THE HEAT RESISTANCE OF LISTERIA MONOCYTOGENES IN BEEF

    Science.gov (United States)

    The effects and interactions of heating temperature (60 - 73.9C), sodium lactate (NaL; 0.0 - 4.8%, w/w) and/or sodium diacetate SDA; 0.0 - 0.25%, w/w) on the heat resistance of a five-strain mixture of Listeria monocytogenes in 75% lean ground beef were examined. Thermal death times were determined...

  16. Ocorrência de fungos filamentosos termo-resistentes em polpa de tomate envasada assepticamente / Occurrence of heat resistant molds in tomato pulp packed aseptically

    Scientific Electronic Library Online (English)

    Flávio, BAGLIONI; Homero Ferracini, GUMERATO; Pilar Rodriguez, MASSAGUER.

    1999-05-01

    Full Text Available Este trabalho teve como objetivo principal determinar a ocorrência de fungos filamentosos termo-resistentes durante o processamento asséptico de polpa de tomate (8° BRIX). Durante o período de safra de tomate foram feitas amostragens em 9 lotes (3 no início, 3 no pico e 3 em fim de safra) e no perío [...] do de entresafra em 5 lotes. Foi feita a enumeração de fungos termo-resistentes nas amostras coletadas durante as diferentes etapas do processo asséptico de cada lote. Foram obtidas contagens médias relativamente baixas, variando entre Abstract in english This work aimed at determining the occurrence of heat resistant molds during the aseptic processing of tomato pulp (8° BRIX). During tomato harvest, 9 lots were sampled (3 at the beginning, 3 at the apex and 3 at the end of harvest) and other 5 lots were sampled between harvest. For each lot, the en [...] umeration of heat resistant molds was carried out in samples collected during the aseptic process. The mean count of heat resistant molds was relatively low, ranging from

  17. Modeling the combined effects of pH, temperature and ascorbic acid concentration on the heat resistance of Alicyclobacillus acidoterrestis.

    Science.gov (United States)

    Bahçeci, K Sava?; Acar, Jale

    2007-12-15

    In this study, thermal inactivation parameters (D- and z-values) of Alicyclobacillus acidoterrestris spores in McIlvaine buffers at different pH, apple juice and apple nectar produced with and without ascorbic acid addition were determined. The effects of pH, temperature and ascorbic acid concentration on D-values of A. acidoterrestris spores were also investigated using response surface methodology. A second order polynomial equation was used to describe the relationship between pH, temperature, ascorbic acid concentration and the D-values of A. acidoterrestris spores. Temperature was the most important factor on D-values, and its effect was three times higher than those of pH. Although the statistically significant, heat resistance of A. acidoterrestris spores was not so influenced from the ascorbic acid within the concentration studied. D-values in apple juice and apple nectars were higher than those in buffers as heating medium at similar pH. The D-values ranged from 11.1 (90 degrees C) to 0.7 min (100 degrees C) in apple juice, 14.1 (90 degrees C) to 1.0 min (100 degrees C) in apple nectar produced with ascorbic acid addition, and 14.4 (90 degrees C) to 1.2 min (100 degrees C) in apple nectar produced without ascorbic acid addition. However, no significant difference in z-values was observed among spores in the juices and buffers at different pH, and it was between 8.2 and 9.2 degrees C. The results indicated that the spores of A. acidoterrestris may survive in fruit juices and nectars after pasteurization treatment commonly applied in the food industry. PMID:17936391

  18. Corrosion performance of structural alloys.

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.

    1999-07-15

    Component reliability and long-term trouble-free performance of structural materials are essential in power-generating and gasification processes that utilize coal as a feedstock. During combustion and conversion of coal, the environments encompass a wide range of oxygen partial pressures, from excess-air conditions in conventional boilers to air-deficient conditions in 10W-NO{sub x} and gasification systems. Apart from the environmental aspects of the effluent from coal combustion and conversion, one concern from the systems standpoint is the aggressiveness of the gaseous/deposit environment toward structural components such as waterwall tubes, steam superheaters, syngas coolers, and hot-gas filters. The corrosion tests in the program described in this paper address the individual and combined effects of oxygen, sulfur, and chlorine on the corrosion response of several ASME-coded and noncoded structural alloys that were exposed to air-deficient and excess-air environments typical of coal-combustion and gasification processes. Data in this paper address the effects of preoxidation on the subsequent corrosion performance of structural materials such as 9Cr-1Mo ferritic steel, Type 347 austenitic stainless steel, Alloys 800, 825, 625, 214, Hastelloy X, and iron aluminide when exposed at 650 C to various mixed-gas environments with and without HCI. Results are presented for scaling kinetics, microstructural characteristics of corrosion products, detailed evaluations of near-surface regions of the exposed specimens, gains in our mechanistic understanding of the roles of S and Cl in the corrosion process, and the effect of preoxidation on subsequent corrosion.

  19. Effect of impurities on the proneness to temper embrittlement of heat resistant Cr-Mo-V steel

    International Nuclear Information System (INIS)

    The authors investigated the effect of most alloying elements which are traditionaly regarded as dangerous in low-alloy structural steels--sulfur, phosphorus, copper, arsenic, antimony, tin--on the proneness to temper embrittlement of steel 25Kh1M1F which is used for making large all-forged rotors of fixed and transport medium-pressure steam turbines. On the basis of the obtained results it may be concluded that from among the investigated alloying elements only phosphorus and antimony have a statistically significant effect on the proneness of fine-grained steel 25Kh1M1F to temper embrittlement, and the embrittling effect of phosphorus is much stronger than the embrittling effect of antimony

  20. Carbon corrosion of alloys at high temperature

    Scientific Electronic Library Online (English)

    D.J., Young; J., Zhang.

    2013-02-01

    Full Text Available Alloys used at high temperature must resist both creep and corrosion. Design for corrosion resistance is based on the formation of a slow-growing, protective oxide scale by selective oxidation of an appropriate alloy component, usually chromium or aluminium. A successful scale will exclude other cor [...] rodents, notably carbon, which can otherwise cause extremely rapid corrosion at high temperatures. Selective oxidation of an alloy component necessarily lowers the concentration of that metal in the alloy subsurface region. Under thermal cycling conditions, mechanical damage to the scale leads to renewed oxide growth and accelerated alloy depletion. Eventually, a point is reached where diffusion of a corrodent into the alloy becomes competitive with the outward diffusion of alloy metal to repair the protective scale. Two examples of alloy failure by carbon attack are considered. In the steam cracking (pyrolysis) process, centrifugally cast tubes of heat-resisting alloy are exposed to a gas stream of hydrocarbon and steam, at a carbon activity of unity. Formation and repair of the surface chromia scale causes alloy depletion, Kirkendall void formation, and subsequent internal precipitation of chromium-rich carbides. Their formation makes chromia scale formation much more difficult, and generates internal stress. Eventually, the tubes fail by creep rupture. In other processes (e.g. steam reforming, heat treatment), synthesis gases are supersaturated with carbon at intermediate temperatures. Once the alloy's protective scale is breached, carbon attacks the depleted substrate. In the case of ferritic alloys, it forms a surface scale of Fe3C. As this scale thickens, the supersaturated carbon precipitates as graphite within its outer regions. The resulting volume expansion causes disintegration of the cementite in a process known as metal dusting. In the case of austenitic alloys, no metal carbide is formed. Instead, carbon dissolves in the depleted metal to diffuse inward and precipitate as graphite within the metal matrix. Again, volume expansion causes disintegration of the alloy, and metal dusting results. Dusting occurs at an extraordinarily rapid rate, and leads to failure by section loss or even penetration.

  1. Properties of alloys on the titanium base for powerful steam turbine blades

    International Nuclear Information System (INIS)

    The results of investigation of VT20, VT22, AT6 titanium alloys properties under the conditions of blade operation of powerful steam turbines are considered. It is shown that VT20, VT22, AT6 alloys under investigation comply with the requirements of existing technical task according to short-term mechanical properties, fatigue strength, heat-resistant characteristics at operation temperature (100 deg C), VT20 and VT22 alloys also comply with the requirements for prospective turbines, AT6 alloy properties approach to these requirements. VT20 alloy meet the established requirements on perspectivity in the most complete way according to the most favourable combination of operation properties and to the level of separate characteristics

  2. Effect of yttrium on the cyclic oxidation behaviour of HP40 heat-resistant steel at 1373 K

    International Nuclear Information System (INIS)

    Research highlights: ? Yttrium has a benefit effect on the cyclic oxidation resistance of HP40 alloy. ? Y facilitates the formation of internal oxide (silica) during cyclic oxidation. ? A continuous spinel layer is observed on Y doped alloy during cyclic oxidation. ? The internal oxide (silica) improves the adherence of the scale. - Abstract: The effect of rare earth elements on cyclic oxidation behaviour of HP40 at 1373 K has been investigated. The results demonstrate that 0.06 wt.% addition of Y effectively improves the cyclic oxidation resistance of such Si-containing alloy. By observing the cross-section of the scale, it is found that Y facilitates the formation of Si-rich internal oxide, which improves the spalling resistance of the scale. As a result, compared with the sample without Y addition, on which the spinel layer is discontinuous, a continuous duplex scale of chromia overlaid by manganese-rich spinel is kept at the outmost of the Y-modified alloy.

  3. Results from investigations with an instrumented impact machine on a molybdenum base alloy, nickel base alloys, and Incoloy 800

    International Nuclear Information System (INIS)

    Experiments were performed on the molybdenum base alloy TZM, the nickel base alloys Nimocast 713 LC, Inconel 625, Nimonic 86, Hastelloy S, and the iron base alloy Incoloy 800 with an instrumented impact machine. The results are discussed in terms of absorbed impact energies and dynamic fracture toughness. In all cases the agreement between the energy determined by the dial reading and the energy determined by the integration of the load vs. load point displacement diagram was excellent. A procedure for the determination of the dynamic fracture toughness for load vs. load point displacement diagrams exhibiting high oscillations using an averaged curve is proposed. Using this procedure a pronounced influence of the experiments with tup and chisel (5.0 m/s and 0.1 m/s respectively) on the dynamic fracture toughness is not detectable. Using half the drop height, i.e. halving the total energy, lowers the dynamic fracture toughness values for these types of alloys. Low absorbed impact energies are often combined with high fracture toughness values. In these cases there is no or only a small reserve in deformation and/or stable crack growth. (Auth.)

  4. Results from investigations with an instrumented impact machine on a molybdenum base alloy, nickel base alloys, and Incoloy 800

    Energy Technology Data Exchange (ETDEWEB)

    Krompholz, K.; Tipping, P.; Ullrich, G.

    1984-04-01

    Experiments were performed on the molybdenum base alloy TZM, the nickel base alloys Nimocast 713 LC, Inconel 625, Nimonic 86, Hastelloy S, and the iron base alloy Incoloy 800 with an instrumented impact machine. The results are discussed in terms of absorbed impact energies and dynamic fracture toughness. In all cases the agreement between the energy determined by the dial reading and the energy determined by the integration of the load vs. load point displacement diagram was excellent. A procedure for the determination of the dynamic fracture toughness for load vs. load point displacement diagrams exhibiting high oscillations using an averaged curve is proposed. Using this procedure a pronounced influence of the experiments with tup and chisel (5.0 m/s and 0.1 m/s respectively) on the dynamic fracture toughness is not detectable. Using half the drop height, i.e. halving the total energy, lowers the dynamic fracture toughness values for these types of alloys. Low absorbed impact energies are often combined with high fracture toughness values. In these cases there is no or only a small reserve in deformation and/or stable crack growth.

  5. Constitutive equations for the creep behaviour of nickel-base alloys for HTR components in the temperature range 1023-1273 K

    International Nuclear Information System (INIS)

    The applicability and modification of constitutive equations for describing the creep and relaxation behaviour of the nickel-base alloys INCONEL 617, NIMONIC 86 and HASTELLOY S have been investigated. Creep tests at stresses in range 10-150 MPa and temperatures in the range 1023-1273 K were carried out for the three alloys and in addition for INCONEL 617 and HASTELLOY S relaxation and stress dip tests in the stress range 10-170 MPa and temperature range 1073-1223 K were performed. The fitting of various creep equations to the measured creep curves showed that the best description of the primary and secondary creep regions was given by the equation formulated by Li. Under the experimental conditions used, dislocation climb was the dominant deformation mechanism. Using the internal stress concept to account for the resistance to deformation, a Norton creep law exponent of 3 for INCONEL 617 was derived which is in agreement with the value calculated by Weertman for dislocation climb controlled screep in solid solutions. For HASTELLOY S a lower value was observed. The dependence of the internal stress in the temperature and stress range on creep strain, applied stress, deformation prior to testing, temperature and alloy composition was determined. Relaxation and stress dip tests showed two separate time dependent relationships for the reduction of stress or anelastic backstrain. A rapid decrease at the start of the test due to back glide of dislocations and a much slower decrease associated with recovery were observed. Calculation of the stress relaxation behaviour based on the Norton creep law alone led to a time dependence which was not reflected in the experimental results. However, taking into account the internal stress which decreases during the relaxation test due to recovery processes, it was possible to describe satisfactorily the experimentally determined relaxation curves. (orig.)

  6. ??????? ???????????????????? ????????? ?? ?????? ? ????????? ???????????? ???????? ?? ???????????????? ??????????? ?????????? ?????? HIGH-TEMPERATURE OXIDATION INFLUENCE ON COMPOSITION AND STRUC-TURE OF ALUMINIDE COATING ON ION IMPLANTED SURFACE OF NICKEL ALLOY

    Directory of Open Access Journals (Sweden)

    ?. ?. ?????

    2013-01-01

    Full Text Available ??????????? ??????? ???????????????????? ????????? ?? ?????? ? ????????? ????????-??????????? ???????? ????-11, ??????????? ?? ???????? ?? ?????? ???-7?, ???????????????? ?????? ????????. ??????? ????????????????? ????????? ? ???????? ? ?????????? ?????????? ???????? ??? ??????????? 850 ??, ???????? ??????????? ????? ?????????? ????????????? ????????? ? ?????????????????? ????????? ????????. ???????? ???????????? ????????????? ?????? ??????????? ??? ??????? ?????????????? ?????????? ??????????? ?????????? ?????? ??? ????????-?????????? ????????, ?????????????? ????????? ????????????? ??????????? ??????.The paper discusses the influence of high-temperature oxidation on composition and structure of vacuum-plasma coating VSDP-11 deposited on TsNK-7P alloy substrate implanted with ytterbium  ions. The elements redistribution in the coating after exposition at 850 oC was studied and the interdependence between the elements redistribution and the life cycle of the protective coating was established. The ion implantation benefits resulting in the increase of the alloy surface heat resistance were shown for the additional nickel alloy surface treatment for the purpose of vacuum-plasma coating deposition.

  7. Effect of Si and P on Microstructure and Mechanical Properties of Mg-7Al-1Zn-3.597Cu-xSi Alloys

    OpenAIRE

    Keqiang Qiu; Xiaocheng Wang; Junhua You

    2013-01-01

    In order to improve the heat resistant properties of magnesium alloys, the effects of P modification on phase constituent, microstructure and mechanical properties of Mg-7Al-1Zn-3.597Cu-xSi (x=1, 2, 3) alloys were investigated by means of x-ray diffractometer (XRD), scanning electron microscopy (SEM), and universal electronic testing machine. The results indicate that the Mg2Si phase presented in the form of Chinese script shape was observed in the microstructure of the alloy without P elemen...

  8. High ion erosion rates produced on various stainless steels and nickel base alloys by 12 keV He+ ion bombardment

    International Nuclear Information System (INIS)

    Surface changes and ion erosion of stainless steels (316L) and nickel base alloys (Nimonic PE 16, Inconel 600, Hastelloy B) under 6-12 keV He+ ions bombardment at room temperature were systematically investigated using a profilometer, optical and electron microscopes. Results show that for the bombardment conditions mentioned sputtering yield, penetration depth and ion erosion for all materials studied are quite different from the available data. Blistering is found to be highly dependent on the surface preparation, annealing procedure, ion fluence and total ion dose. After 12 keV He+ ion bombardment etching effects were observed accompanied by blistering

  9. Padrão eletroforético de proteínas resistentes ao calor em sementes de milho Electrophorectic pattern of the heat resistant proteins of corn seeds

    Directory of Open Access Journals (Sweden)

    Solange Carvalho Barrios Roveri José

    2005-02-01

    Full Text Available Na aquisição e manutenção da tolerância à dessecação de sementes, há vários mecanismos envolvidos, entre eles a indução das proteínas resistentes ao calor. O objetivo deste trabalho foi avaliar mudanças no padrão eletroforético das proteínas resistentes ao calor de sementes de milho submetidas a alta temperatura de secagem, associando-as à sua tolerância. Foram utilizadas sementes de linhagens, híbridos simples e híbridos recíprocos colhidas com teor de água de aproximadamente 35% e secadas a 45°C. Sementes das linhagens secadas à sombra foram utilizadas como controle e sua qualidade fisiológica foi avaliada por meio do teste de germinação. As proteínas resistentes ao calor foram extraídas de eixos embrionários das sementes em tampão Tris HCl 0,05 M. Não foi possível determinar uma banda específica da fração das proteínas resistentes ao calor que possa servir como marcador da tolerância à alta temperatura de secagem. Houve estabilidade nos padrões de bandas das proteínas provenientes de sementes submetidas à secagem artificial e natural, mesmo quando foram observadas variações nos valores de germinação. Os padrões eletroforéticos das proteínas resistentes ao calor foram semelhantes entre as sementes híbridas e os respectivos recíprocos.Several mechanisms are involved in the acquisition and maintenance of desiccation tolerance by the seeds. One of these mechanisms is related to the induction of heat resitant proteins. The objective of this work was to evaluate changes in the electophorectic patterns of the heat resistant proteins of corn seeds submitted to high drying temperature associating their expression with drying tolerance. Seeds of breeding lines, simple hybrids and respective reciprocals hybrids were utilized. The seeds were harvested with approximately 35% of water content and dried at 45°C. Seeds of lines dried under shadow were used as control and the physiological quality was evaluated by germination test. The heat resistant proteins were extracted from embryonic axis of seeds in Tris-HCl 0.05 M buffer. It was not possible to determine a specific band of heat resistant proteins which can be of use as a molecular marker of tolerance to high drying temperature. There was stability in the patterns of the bands of proteins of seeds submitted to artificial drying compared to the ones after shadow drying even for the lines of high variation in the germination values. The electrophorectic patterns of the heat resistant proteins were similar for both the hybrid seeds and respective reciprocals.

  10. Estimation of high-temperature strength of coast RuAl alloys and other monoaluminides by hot-hardness method

    International Nuclear Information System (INIS)

    Short- and long-term (holding under load up to 1 h) is measured at temperatures up to 1100 Deg C for coast monoaluminides RuAl, NiAl and TiAl serving as a basis for designing heat resistant composite material matrices intended for operation at temperatures in excess of those of modern nickel superalloys. It is shown that a more refractory RuAl surpasses the other monoaluminides in heat resistance within the whole temperature range studied. A more slow development of diffusion processes in RuAl alloys at 1100 Deg C predetermines a high stability of alloy hot hardness values. A single-phase alloy Ru51Al49 possesses the maximum hardness. A study of alloying effects shows that Hf, being most refractory having a great atomic radius and replacing Al in a RuAl B2-lattice, increases the hardness in heterogeneous alloys as exemplified by long-term testing. Titanium has no essential effect on hardness, and chromium promotes alloy softening somewhat

  11. Development of welding wire Sv-08Kh14N7KVM-VI for heat resisting stainless steels

    International Nuclear Information System (INIS)

    The Sv-08Kh14N7KVM-VI wire has been worked out to ensure productio of welded joints of stainless steel with ?sub(U.S.) >= 1200 MPa and to avoid embrittlement during prolonged (up to 500 h) heating in the 450-500 deg C temperature range. It is shown, that embrittlement of welded joints of martensite type stainless steels during prolonged heatings in the 450-500 deg C temperature range can be prevented in the case of complex alloying of the joint with molybdenum and tungsten (1%Mo+0.5%W) with titanium and aluminium additions

  12. Study of superficial films and of electrochemical behaviour of some nickel base alloys and titanium base alloys in solution representation of granitic, argillaceous and salted ground waters

    International Nuclear Information System (INIS)

    The corrosion behaviour of the stainless steels 304, 316 Ti, 25Cr-20Ni-Mo-Ti, nickel base alloys Hastelloy C4, Inconel 625, Incoloy 800, Ti and Ti-0.2% Pd alloy has been studied in the aerated or deaerated solutions at 200C and 900C whose compositions are representative of interstitial ground waters: granitic or clay waters or salt brine. The electrochemical techniques used are voltametry, polarization resistance and complexe impedance measurements. Electrochemical data show the respective influence of the parameters such as temperature, solution composition and dissolved oxygen, addition of soluble species chloride, fluoride, sulfide and carbonates, on which depend the corrosion current density, the passivation and the pitting potential. The inhibition efficiency of carbonate and bicarbonate activities against pitting corrosion is determined. In clay water at 900C, Ti and Ti-Pd show very high passivation aptitude and a broad passive potential range. Alloying Pd increases cathodic overpotential and also transpassive potential. It makes the alloy less sensitive to the temperature effect. Optical Glow Discharge Spectra show three parts in the composition depth profiles of surface films on alloys. XPS and SIMS spectrometry analyses are also carried out. Electron microscopy observation shows that passive films formed on Ti and Ti-Pd alloy have amorphous structure. Analysis of the alloy constituents dissolved in solutions, by radioactivation in neutrons, gives the order of magnitude of the Ni base alloy corrosion rates in various media. It also points out the preferential dissolution of alloying iron and in certain cases of chromium

  13. Improvement of high temperature strength and toughness of 12mass%Cr-15mass%Mn austenitic steels developed as a heat resisting material

    International Nuclear Information System (INIS)

    For the development of a high Mn-Cr austenitic steel as one of the heat resisting materials, the present authors have investigated the high temperature strength, toughness and microstructural phase instability of 12%Cr-15%Mn steels. High content of carbon (0.1 to 0.2 mass%C) formed the large amount of coarse precipitates of the type M23C6 carbide on grain boundaries and within grains after a long-term aging. These precipitates caused the intergranular and/or quasi-cleavage fracture and deteriorated the toughness. It was clarified that, for the improvement of the toughness, the lowering of carbon content to 0.02 mass%C was necessary. The toughness and high temperature strength of the 12%Cr-15%Mn steels were compared and discussed with those of the ordinary SUS316 steel. Creep-rupture strength of the present materials was also compared with that of the TENELON which had been developed by Brady et al (US steel) as a high Mn austenitic heat resisting steel. The creep-rupture strength of the 12%Cr-15%Mn steel was superior to those of the type 316 steel and the TENELON. (author)

  14. Effect of vanadium addition on the creep resistance of 18Cr9Ni3CuNbN austenitic stainless heat resistant steel

    International Nuclear Information System (INIS)

    Highlights: •The first observation of V-rich Z-phase in austenitic stainless steel. •Separate precipitation of Nb-rich MX and V-rich Z-phase in Nb and V contained steel. •The effect of nanometer sized Z-phase on the improvement of creep strength. •The predicted size of MX precipitates by MatCalc agreed well with measured size. -- Abstract: The effect of vanadium addition on the creep property of niobium-containing 18Cr–9Ni austenitic heat-resistant steel was studied. After solution treatment, the MX precipitates of vanadium-free steel contained Nb only. On the contrary, high Nb and low V contents were detected from the MX precipitates in the steel with 0.3 wt% of vanadium. Vanadium-rich MX carbo-nitride was not observed in the matrix and at the grain boundaries after solution treatment. The vanadium precipitated as a form of Z-phase during early-stage creep deformation was attributed to the improvement in creep strength at 700 °C with applied stress higher than 150 MPa. And metallic Cu precipitates were confirmed in the nanometer scale using TEM and EDS technique. The Cu precipitates are believed to contribute to the strengthening of austenitic heat resistant steel independently. The precipitation behavior is discussed using transmission electron microscopy and thermo-kinetics simulation technique

  15. Investigation of weldability and property changes of high pressure heat-resistant cast stainless steel tubes used in pyrolysis furnaces after a five-year service

    International Nuclear Information System (INIS)

    Highlights: ? To investigate the weldability and property changes of high pressure heat-resistant cast stainless steel (HP) tubes. ? Welding was done by gas-tungsten arc welding (GTAW) process. ? Composition of precipitates was characterized by means of SEM and EDS analyses. ? The solution treatment was used to recover the properties of tubes. ? To investigate mechanical strength of specimens, tensile tests were carried out at room temperature. -- Abstract: High pressure heat-resistant cast stainless steel (HP steel) tubes produced by centrifugal casting are used in petrochemical industries for pyrolysis furnaces. They have appropriate ductility and weldability in as-cast conditions. These steels lose their ductility and weldability after being used in service and, hence, require repair. In the present study, the effect of metallurgical changes on weldability and ductility was investigated. The life span of the studied tubes was 5 years. Using electrodes with a chemical composition close to the base metal analysis, welding was done by gas-tungsten arc welding (GTAW) process. Solution treatment was used to recover the properties of tubes which can be useful, depending on metallurgical changes.

  16. The corrosion behavior of high-temperature alloys during exposure for times up to 10,000 h in prototype nuclear process helium at 700 to 9000C

    International Nuclear Information System (INIS)

    A corrosion program is being carried out to establish the long-term corrosion behavior of candidate alloys for the prototype nuclear process (PNP) reactor primary circuit. Results are presented for corrosion tests performed in impure helium over the temperature range of 700 to 9000C for times up to 10 000 h. In the helium atmosphere containing 0.5 to 1.5 /sigma phi/bar H2O, 15 /sigma phi/bar CO, 20 /sigma phi/bar CH4, and 500 /sigma phi/bar H2, the three main PNP reference alloys-Inconel617, Nimonic-86, and Hastelloy-X-exhibit excellent corrosion resistance with the carbon uptakes of 0C. Differences in behavior are related to the composition and morphology of protective surface scales and minor variations in gas impurity levels during test startup. The influence of variations in alloy composition on the long-term stability of these oxide scales is also discussed

  17. Research and development of steel and alloy tubes and pipe for nuclear services

    International Nuclear Information System (INIS)

    This company has been engaged in the research and development of steel and alloy tubes and pipe for nuclear services, among which the results for four products will be described as follows: (1) Zircaloy tubes for nuclear fuel cladding : the improvement of manufacturing and inspection techniques, the research on improvement in quality of the product (corrosion resistance, texture, hydride precipitation characteristics, mechanical properties, etc.), and irradiation test. (2) Steam generator tubes for a high temperature gas cooled reactor for power generating : high temperature strength, structure change, and oxidation resistance and weldability of Fe-32Ni-20Cr-Ti-Al alloy. (3) Heat resistant alloys for heat exchanger tubes in nuclear steel-making : high temperature strength and oxidation resistance of several kinds of heat resistant alloys, and the introduction of newly installed helium circulating loop system for material testing. (4) Ultra-high strength steel pipe for manufacturing equipment of nuclear fuel material : results of research on improvement in quality of 300ksi and 350ksi grade maraging steels. (auth.)

  18. The structure and properties of KhN60VT alloyed with Zr

    International Nuclear Information System (INIS)

    The effect of zirconium on the KhN60VT nickel chrome-tungsten alloy is studied. The chemical composition, mechanical and heat-resistant properties as well as the macro- and microstructure in castings, obtained through the method of vacuum remelting and heat treatment at 11800 deg C with subsequent cooling in the air and aging at 815 deg C are determined. It is established, that with increase of zirconium content up to 2.98 % the macrograin grew smaller, the microporosity declined, and the eutectics average sizes and content increased. The long-term strength of the KhN60VT alloy, containing 2.98 % Zr, is by 50-60 times higher than that of the alloy samples without zirconium. Introduction of 1.39 % Zr leads to increase in the long-term strength approximately by 7 times. The observed significant growth of heat resistance in the alloy with zirconium is explained by the effect of dispersion hardening by the ?-phase separation, strengthened by the effect of temperature and applied voltage during tests for the long-term strength

  19. Precipitation behavior and phase stability of intermetallic phases in Fe-Cr-W-Co ferritic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, K.; Kimura, Y.; Mishima, Y. [Dept. of Materials Science and Engineering, Tokyo Inst. of Tech., Yokohama (Japan)

    2005-07-01

    Precipitation behavior of intermetallic phases in ferrite matrix is investigated by transmission electron microscopy (TEM) in Fe-10Cr-1.4W-4.5Co (at%) alloys with and without 0.3at%Si. It is intended to provide basic information for the alloy design of ferritic heat resistant alloys strengthened by intermetallic compounds. In the alloy containing Si, icosahedral quasicrystalline phase (I-phase) is found to precipitate during aging at 873 K. It is confirmed that selected area diffraction (SAD) patterns of the precipitates exhibit two-, three- and five-fold symmetry and have diffraction spots in the positions related to the golden section. In the Si-free alloy, the R-phase precipitates instead of I-phase at 873 K, and the laves phase precipitates in both alloys during aging at higher temperature, 973 K. The laves phase formed at 973 K transforms to the I-phase in the Si-added alloy but to the R-phase in the Si-free alloy during subsequent aging at 873 K. The factors in controlling the phase stability of I-phase, R-phase and laves phase precipitates in Fe-based alloys are discussed by the atomic size ratio and electron concentration factor (e/a). (orig.)

  20. Carburization of austenitic alloys by gaseous impurities in helium

    International Nuclear Information System (INIS)

    The carburization behavior of Alloy 800H, Inconel Alloy 617 and Hastelloy Alloy X in helium containing various amounts of H2, CO, CH4, H2O and CO2 was studied. Corrosion tests were conducted in a temperature range from 649 to 10000C (1200 to 18320F) for exposure time up to 10,000 h. Four different helium environments, identified as A, B, C, and D, were investigated. Concentrations of gaseous impurities were 1500 ?atm H2, 450 ?atm CO, 50 ?atm CH4 and 50 ?atm H2O for Environment A; 200 ?atm H2, 100 ?atm CO, 20 ?atm CH4, 50 ?atm H2O and 5 ?atm CO2 for Environment B; 500 ?atm H2, 50 ?atm CO, 50 ?atm CH4 and 2O for Environment C; and 500 ?atm H2, 50 ?atm CO, 50 ?atm CH4 and 1.5 ?atm H2O for Environment D. Environments A and B were characteristic of high-oxygen potential, while C and D were characteristic of low-oxygen potential. The results showed that the carburization kinetics in low-oxygen potential environments (C and D) were significantly higher, approximately an order of magnitude higher at high temperatures, than those in high-oxygen potential environments (A and B) for all three alloys. Thermodynamic analyses indicated no significant differences in the thermodynamic carburization potential between low- and high-oxygen potential environments. It is thus believed that the enhanced carburization kinetics observed in the low-oxygen potential environments were related to kinetic effects. A qualitatively mechanistic model was proposed to explain the enhanced kinetics. The present results further suggest that controlling the oxygen potential of the service environment can be an effective means of reducing carburization of alloys

  1. Diffusion aluminide coatings for protecting the surface of the internal space of single-crystal turbine blades made of rhenium- and rhenium-ruthenium-containing high-temperature alloys: Part II

    Science.gov (United States)

    Muboyadzhyan, S. A.; Galoyan, A. G.

    2013-03-01

    The production of heat-resistant aluminide and chromium aluminide protective coatings with a barrier layer, which is based on the carbides of the refractory elements of a nickel superalloy, is considered for the powder methods of diffusion chromium and aluminum saturation of the surface of the internal space of single-crystal high-pressure turbine blades made of high-temperature rhenium- and rhenium-ruthenium-containing alloys for a gas turbine engine. The barrier layer is shown to prevent the formation of a secondary reaction zone, which softens an alloy, under a heat-resistant coating during long-term high-temperature holding. The kinetics of powder-assisted aluminizing and chromizing-aluminizing of high-temperature rhenium- and rhenium-ruthenium-containing alloys is studied, aluminizing and chromizing-aluminizing conditions are determined, and the effect of heat-resistant diffusion coatings with a barrier layer on the mechanical properties of the high-temperature alloys is investigated.

  2. Fundamental studies on electron beam welding of heat-resistant superalloys for nuclear plants (Report I). Effect of welding conditions on some characteristics of weld bead

    International Nuclear Information System (INIS)

    The effect of the welding conditions on the characteristics of the weld geometry and the weld defects was made clear, concerning the heat-resistant superalloys for nuclear plants. Obtained conclusion may be summarized as follows: the weld defects were R-porosity and microcrack, S/sub p/ and ?A/sub b/ are considered to be the important criteria for the evaluation of the susceptibility to the R-porosity; superalloys could be evaluated in the sensitivity to the microcrack in terms of the critical heat input to avoid microcrack q/sub cr/. This q/sub cr/ is considered to be one of the proper criteria for evaluating the superalloys in the susceptibility to the microcrack, and most microcracks were apt to occur when h/sub c/h/sub N/ came near to 1.0. These microcracks came to occur easily with the increase of d/sub B.N//d/sub B/

  3. Porous membrane with high curvature, three-dimensional heat-resistance skeleton: a new and practical separator candidate for high safety lithium ion battery

    Science.gov (United States)

    Shi, Junli; Xia, Yonggao; Yuan, Zhizhang; Hu, Huasheng; Li, Xianfeng; Zhang, Huamin; Liu, Zhaoping

    2015-02-01

    Separators with high reliability and security are in urgent demand for the advancement of high performance lithium ion batteries. Here, we present a new and practical porous membrane with three-dimension (3D) heat-resistant skeleton and high curvature pore structure as a promising separator candidate to facilitate advances in battery safety and performances beyond those obtained from the conventional separators. The unique material properties combining with the well-developed structural characteristics enable the 3D porous skeleton to own several favorable properties, including superior thermal stability, good wettability with liquid electrolyte, high ion conductivity and internal short-circuit protection function, etc. which give rise to acceptable battery performances. Considering the simply and cost-effective preparation process, the porous membrane is deemed to be an interesting direction for the future lithium ion battery separator.

  4. Effect of sporulation medium on wet-heat resistance and structure of Alicyclobacillus acidoterrestris DSM 3922-type strain spores and modeling of the inactivation kinetics in apple juice.

    Science.gov (United States)

    Molva, Celenk; Baysal, Ayse Handan

    2014-10-17

    Alicyclobacillus acidoterrestris is a spoilage bacterium in fruit juices leading to high economic losses. The present study evaluated the effect of sporulation medium on the thermal inactivation kinetics of A. acidoterrestris DSM 3922 spores in apple juice (pH3.82±0.01; 11.3±0.1 °Brix). Bacillus acidocaldarius agar (BAA), Bacillus acidoterrestris agar (BATA), malt extract agar (MEA), potato dextrose agar (PDA) and B. acidoterrestris broth (BATB) were used for sporulation. Inactivation kinetic parameters at 85, 87.5 and 90°C were obtained using the log-linear model. The decimal reduction times at 85°C (D85°C) were 41.7, 57.6, 76.8, 76.8 and 67.2min; D87.5°C-values were 22.4, 26.7, 32.9, 31.5, and 32.9min; and D90°C-values were 11.6, 9.9, 14.7, 11.9 and 14.1min for spores produced on PDA, MEA, BATA, BAA and BATB, respectively. The estimated z-values were 9.05, 6.60, 6.96, 6.15, and 7.46, respectively. The present study suggests that the sporulation medium affects the wet-heat resistance of A. acidoterrestris DSM 3922 spores. Also, the dipicolinic acid content (DPA) was found highest in heat resistant spores formed on mineral containing media. After wet-heat treatment, loss of internal volume due to the release of DPA from spore core was observed by scanning electron microscopy. Since, there is no standardized media for the sporulation of A. acidoterrestris, the results obtained from this study might be useful to determine and compare the thermal resistance characteristics of A. acidoterrestris spores in fruit juices. PMID:25129530

  5. Design of ductile polycrystalline Ni/sub 3/Al alloys

    International Nuclear Information System (INIS)

    This paper provides a comprehensive review of current efforts on design of ductile polycrystalline Ni/sub 3/Al alloys. Microalloying has proven to be very effective in alleviating the grain-boundary embrittlement problem. The ductility and fabricability of Ni/sub 3/Al (24 at. % Al) are dramatically improved by adding a few hundred parts per million of boron. The beneficial effect of boron is related to its unusual segregation behavior as predicted from the theory of grain-boundary cohesion developed by Rice, based on thermodynamic analyses. Alloy stoichiometry strongly influences grain-boundary chemistry, which, in turn, affects the boundary cohesion and overall ductility of Ni/sub 3/Al. The solid-solution hardening of Ni/sub 3/Al depends on the substitutional behavior of alloying elements, atomic size misfit, and the degree of nonstoichiometry of the alloy. Hafnium additions are very effective in improving high-temperature properties of ternary Ni/sub 3/Al (Al + Hf = 24 at. %) doped with boron. Alloying with ? 2% Hf substantially increases the yield stress and raises the peak-strength temperature. In addition, hafnium substantially improves creep properties and oxidation resistance. The Ni/sub 3/Al aluminides truly represent a new series of heat resistant materials which do not depend on chromium for oxidation resistance

  6. Investigation of corrosion and analysis of passive films concerning some nickel alloys and stainless steels in reconstructed geological environments

    International Nuclear Information System (INIS)

    This research thesis addresses the corrosion behaviour of materials which might be used for the fabrication of radioactive waste containers. After a bibliographical study on films formed on Fe-Cr-Ni alloys, this research concentrates on passivation and de-passivation phenomena of three nickel-base alloys among the most resistant to corrosion and which also meet processing and economic criteria: Hastelloy C4, Inconel 625 and ZICNDU 25-20. Titanium and Ti-Pd alloy are also studied. Parameters governing pitting corrosion are notably studied. After a recall of knowledge on passive films formed on Fe-Cr-Ni alloys, and a presentation of experimental and technical conditions, the author reports and discussed the results obtained by electrochemical studies, reports the determination of factors governing alloy passivation in geological waters. The influence of some soluble impurities is notably studied. The author reports the analysis by glow discharge optical emission spectrometry to determine the composition of passive films with respect to geological water nature, the immersion duration and the electrode potential. Additional surface analyses are performed by X-ray photoelectron spectrometry (XPS or ESCA) and secondary ion mass spectrometry (SIMS). Finally, the author uses a dosing method by neutron radio-activation of alloy elements to determine dissolution mechanisms

  7. Bimetallic layered castings alloy steel – grey cast iron

    Directory of Open Access Journals (Sweden)

    T. Wróbel

    2011-04-01

    Full Text Available Purpose: In paper is presented technology of bimetallic layered castings based on founding method of layer coating directly in cast process so-called method of mould cavity preparation.Design/methodology/approach: Prepared bimetallic layered castings consist two fundamental parts i.e. bearing part and working part (layer. The bearing part of bimetallic layered casting is typical foundry material i.e. pearlitic grey cast iron, whereas working part (layer is depending on accepted variant plates of alloy steels sort X6Cr13, X12Cr13, X10CrNi18-8 and X2CrNiMoN22-5-3. The ratio of thickness between bearing and working part is 8:1. The verification of the bimetallic layered castings was evaluated on the basis of ultrasonic NDT (non-destructive testing, structure and macro- and microhardness researches. Moreover was made computer simulation of solidification of bimetallic layered casting in NovaFlow&Solid software.Findings: The results of studies and their analysis show efficiency of new, innovative technology of corrosion and heat resisting layered castings.Research limitations: In further research, authors of this paper are going to application of different material on bearing part of bimetallic layered casting.Practical implications: Prepared bimetallic layered castings according to work out technology can work in conditions, which require from working surface layer of element a high heat resistance and/or corrosion resistance in medium for example of industrial water.Originality/value: The value of this paper resides in new effective method of manufacture of heat resisting castings, mainly for lining of quenching car to coke production

  8. Mechanism and kinetics of ?'-phase in nickel alloys at hot working temperatures

    International Nuclear Information System (INIS)

    The changes in behaviour of strengthening ?'-phase within the temperature range of 700-1200 deg C were investigated for a heat resistant high alloy EHP741 (Ni-15.8%Co-8.8%Cr-6.8%W-4.9%Al-2.6%Mo-1.6%Nb-1.4%Ti-0.048%C). Hot deformation was performed by upsetting at 1100 deg C with a 40% reduction. Microscopic examination of the alloy specimens annealed under various conditions showed that the coagulation of strengthening phase particles follows a parabolic law. The initial structural state has a great effect on the rate of coagulation. For heavily deformed material with high dislocation density and high matrix-strengthening phase interfacial energy on holding in a two-phase temperature range the rate of coagulation appears to be much higher than for homogenized alloys. 3 refs., 3 figs

  9. Cast Intermetallic Alloys and Composites Based on Them by Combined Centrifugal Casting—SHS Process

    Directory of Open Access Journals (Sweden)

    Vladimir Sanin

    2013-08-01

    Full Text Available This work aims to establish a scientific and engineering background in the production of cast multicomponent alloys and metalmartix composite (MMCs via Self-Propagating High Temperature Synthesis (SHS, combustion synthesis which is a novel process technique regarding fast and low-cost production ability. We carried out the search for reactive systems and process parameters that would ensure preparation of cast multicomponent materials in a single process. The principles and methods of the SHS thermite-type reaction processes have been investigated under high-gravity values applying loads up to 1000 g with special centrifuge set-up. In this way we expected to improve the yield of target product, remove gaseous byproducts, diminish the grain size in the product, and make product composition more uniform. The obtained results can be expected to make a theoretical background for industrial-scale manufacturing of heat-resistant intermetallic alloys, master alloys, catalysts, MMCs etc.

  10. Hot extruded high-temperature alloy tubes and some mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Aigner, H.; Degischer, H.P.; Hertner, E.

    1984-07-01

    Seamless hot extruded tubes serve as structural materials of high-temperature gas-cooled reactors and coal conversion systems with exposure temperatures up to 1000/sup 0/C. The tube dimensions ( about130- X 15-mm diam) were produced according to the proposed requirements for methane reformer heat exchangers of nuclear process gas production systems. The most sensitive extrusion parameter is the temperature of the expanded billet at the press, where it should reach 1140 to 1180/sup 0/C depending on the materials investigated: Incoloy-800H, Incoloy-802, Hastelloy-X, Inconel-617, and Nimonic-86. To qualify the extrusion products, the mechanical properties obtained from tensile tests at room temperature and temperatures up to 1000/sup 0/C are compared for tube products. Strengthening effects at 800/sup 0/C are explained by carbide precipitation during the test, especially of alloys 800H and 802.

  11. Hot extruded high-temperature alloy tubes and some mechanical properties

    International Nuclear Information System (INIS)

    Seamless hot extruded tubes serve as structural materials of high-temperature gas-cooled reactors and coal conversion systems with exposure temperatures up to 10000C. The tube dimensions ( about130- X 15-mm diam) were produced according to the proposed requirements for methane reformer heat exchangers of nuclear process gas production systems. The most sensitive extrusion parameter is the temperature of the expanded billet at the press, where it should reach 1140 to 11800C depending on the materials investigated: Incoloy-800H, Incoloy-802, Hastelloy-X, Inconel-617, and Nimonic-86. To qualify the extrusion products, the mechanical properties obtained from tensile tests at room temperature and temperatures up to 10000C are compared for tube products. Strengthening effects at 8000C are explained by carbide precipitation during the test, especially of alloys 800H and 802

  12. Effect of fission product interactions on the corrosion and mechanical properties of HTGR alloys

    International Nuclear Information System (INIS)

    Preliminary experiments have been carried out to determine how fission product interactions may influence the mechanical integrity of reference HTGR structural metals. In this work Type 304 stainless steel, Incoloy 800 and Hastelloy X were heated to 550 - 6500C in the presence of CsI. It was found that no corrosion of the alloys occurred unless air or oxygen was also present. A mechanism for the observed behavior is proposed. A description is also given of some long term exposures of HTGR materials to more prototypic, low concentrations of I2, Te2 and CsI in the presence of low partial pressures of O2. These samples are scheduled for mechanical bend tests after exposure to determine the degree of embrittlement. (author)

  13. High frequency fatigue test of IN 718 alloy – microstructure and fractography evaluation

    OpenAIRE

    Belan, J.

    2015-01-01

    INCONEL alloy 718 is a high-strength, corrosion-resistant nickel chromium material used at -253 °C to 705 °C for production of heat resistant parts of aero jet engine mostly. The fatigue test provided on this kind materials were done via low frequency loading up to this time. Nowadays, needs of results at higher volume of loading cycles leads to high frequency loading with aim to shorten testing time. Fatigue test of experimental material was carried out at frequency 20 kHz with stress rati...

  14. Isolamento e seleção de fungos filamentosos termorresistentes em etapas do processo produtivo de néctar de maçã Isolation and selection of heat resistant molds in the production process of apple nectar

    Directory of Open Access Journals (Sweden)

    Beatriz de Cássia Martins Salomão

    2008-03-01

    Full Text Available Os fungos filamentosos termorresistentes são capazes de sobreviver aos processos de pasteurização aplicados aos produtos de frutas. Este estudo visou isolar e identificar fungos termorresistentes durante o processamento de néctar de maçã (pH 3,4 e 11,6 °Brix, de forma a selecionar o bolor mais termorresistente. O isolamento foi obtido após choque térmico de 70 °C/2 horas e incubação a 30 °C em PDA (3% de ágar acrescido de rosa de bengala. A identificação foi baseada na morfologia e nas estruturas micro e macroscópicas observadas após incubação das cepas em três diferentes meios (G25N, CYA e MEA e temperaturas. O fungo mais termorresistente foi selecionado pela aplicação de choques térmicos (de 80 °C/20 minutos até 97 °C/15 minutos. Foram detectadas 11 linhagens de bolores, sendo 5 termorresistentes. Dentre estas, três cepas, isoladas da matéria-prima e do concentrado de maçã, foram identificadas como Neosartorya fischeri; uma cepa isolada da matéria-prima foi identificada como Byssochlamys fulva, e uma cepa isolada do produto após a primeira pasteurização foi identificada como Eupenicillium sp. As cepas mais resistentes foram as de N. fischeri e B. fulva, que sobreviveram ao tratamento de 95 °C/20 minutos. Dentre as seis cepas restantes, uma foi identificada como Aspergillus sp., entretanto, nenhuma destas apresentou termorresistência.Heat resistant molds are able to survive the pasteurization process applied to apple products. This study aimed at detecting and identifying heat resistant molds during the processing of apple nectar (pH 3.4; 11.6 °Brix in order to select the most heat resistant mold. The isolation was carried out after heat shock at 70 °C, during 2 hours, and incubation at 30 °C, in PDA (3% agar, where rose bengal was added. The identification of macro and microscopic structures was carried out after incubation in three different media (G25N, CYA, MEA and temperatures. Different heat shocks, from 80 °C/20 minutes to 97 °C/15 minutes, were applied to select the most heat resistant mold. Eleven strains were selected, of which five were heat-resistant: three strains were isolated from apple and concentrated apple juice and were identified as Neosartorya fischeri; one strain, isolated from apple, was identified as Byssochlamys fulva and one strain, isolated from the product after the first pasteurization, was identified as Eupenicillium sp. The most heat-resistant strains belong to N. fischeri and B. fulva, which were able to survive at 95 °C/20 minutes. Among the six remaining, one was identified as Aspergillus sp., however, none of them was heat resistant.

  15. Isolamento e seleção de fungos filamentosos termorresistentes em etapas do processo produtivo de néctar de maçã / Isolation and selection of heat resistant molds in the production process of apple nectar

    Scientific Electronic Library Online (English)

    Beatriz de Cássia Martins, Salomão; Pilar Rodriguez, Massaguer; Gláucia Maria Falcão, Aragão.

    2008-03-01

    Full Text Available Os fungos filamentosos termorresistentes são capazes de sobreviver aos processos de pasteurização aplicados aos produtos de frutas. Este estudo visou isolar e identificar fungos termorresistentes durante o processamento de néctar de maçã (pH 3,4 e 11,6 °Brix), de forma a selecionar o bolor mais term [...] orresistente. O isolamento foi obtido após choque térmico de 70 °C/2 horas e incubação a 30 °C em PDA (3% de ágar) acrescido de rosa de bengala. A identificação foi baseada na morfologia e nas estruturas micro e macroscópicas observadas após incubação das cepas em três diferentes meios (G25N, CYA e MEA) e temperaturas. O fungo mais termorresistente foi selecionado pela aplicação de choques térmicos (de 80 °C/20 minutos até 97 °C/15 minutos). Foram detectadas 11 linhagens de bolores, sendo 5 termorresistentes. Dentre estas, três cepas, isoladas da matéria-prima e do concentrado de maçã, foram identificadas como Neosartorya fischeri; uma cepa isolada da matéria-prima foi identificada como Byssochlamys fulva, e uma cepa isolada do produto após a primeira pasteurização foi identificada como Eupenicillium sp. As cepas mais resistentes foram as de N. fischeri e B. fulva, que sobreviveram ao tratamento de 95 °C/20 minutos. Dentre as seis cepas restantes, uma foi identificada como Aspergillus sp., entretanto, nenhuma destas apresentou termorresistência. Abstract in english Heat resistant molds are able to survive the pasteurization process applied to apple products. This study aimed at detecting and identifying heat resistant molds during the processing of apple nectar (pH 3.4; 11.6 °Brix) in order to select the most heat resistant mold. The isolation was carried out [...] after heat shock at 70 °C, during 2 hours, and incubation at 30 °C, in PDA (3% agar), where rose bengal was added. The identification of macro and microscopic structures was carried out after incubation in three different media (G25N, CYA, MEA) and temperatures. Different heat shocks, from 80 °C/20 minutes to 97 °C/15 minutes, were applied to select the most heat resistant mold. Eleven strains were selected, of which five were heat-resistant: three strains were isolated from apple and concentrated apple juice and were identified as Neosartorya fischeri; one strain, isolated from apple, was identified as Byssochlamys fulva and one strain, isolated from the product after the first pasteurization, was identified as Eupenicillium sp. The most heat-resistant strains belong to N. fischeri and B. fulva, which were able to survive at 95 °C/20 minutes. Among the six remaining, one was identified as Aspergillus sp., however, none of them was heat resistant.

  16. Influence of carburization on the room temperature tensile properties of high temperature alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ennis, P.J.; Lupton, D.F.; Nickel, H.; Schuster, H.

    1982-05-01

    The influence of both thermal exposure and carburization at 800 deg C and above on the room temperature tensile properties of INCOLOY 800 H, INCONEL 617, HASTELLOY X and NIMONIC 86 was studied and the results were compared with literature data. The room temperature ductility of INCOLOY 800 H is much less sensitive to carburization than that of the nickel based alloys. This is attributed to the greater volume fraction of carbide formed in the nickel based alloys for a particular bulk carbon content. In the nickel based alloys carbide volume fractions are higher than in IRON based alloys due to the lower solubility of carbon and to the formation of M6C carbides. The ductility of reformer and intermediate heat exchanger (IHX) tubes after long service times in a process heat high temperature reactor was estimated using carburization rates found in corrosion experiments. The data indicate that a reformer tube of INCOLOY 800 H should retain a room temperature ductility equivalent to 5% tensile elongation over the anticipated service life of 140,000 h.

  17. Tensile and impact properties of candidate alloys for high-temperature gas-cooled reactor applications

    International Nuclear Information System (INIS)

    The tensile properties of solution-treated Incoloy alloy 800H, Hastelloy-X, Nimonic-86, and Inconel-617 have been determined in the temperature range 20 to 10000C. The strength parameters at temperatures above 7000C showed a strong dependence on the strain rate; at low strain rates the deformation was dominated by creep effects, the strain rate and maximum stress being related by the Norton creep equation. The tensile and impact properties of the alloys were also determined after exposure at 700 to 10000C for up to 30 000 h. For Incoloy-800H, the results showed good retention of ductility and impact strength. The nickel-base alloys, in contrast, were found to have low room-temperature impact resistance after long time exposure at 700 to 9000C, typical values being 10 to 20 J x cm-2. In impact tests at the exposure temperature, impact strengths were generally above 50 J x cm-2. At room temperature, allowances in design must be made for the low impact strength of the nickel-base alloys to ensure against brittle fracture. For example, excessive stresses during cooling of components following shutdown should be avoided

  18. Tensile and impact properties of candidate alloys for high-temperature gas-cooled reactor applications

    Energy Technology Data Exchange (ETDEWEB)

    Bruch, U.; te Heesen, E.; Ennis, F.J.; Schuhmacher, D.

    1984-08-01

    The tensile properties of solution-treated Incoloy alloy 800H, Hastelloy-X, Nimonic-86, and Inconel-617 have been determined in the temperature range 20 to 1000/sup 0/C. The strength parameters at temperatures above 700/sup 0/C showed a strong dependence on the strain rate; at low strain rates the deformation was dominated by creep effects, the strain rate and maximum stress being related by the Norton creep equation. The tensile and impact properties of the alloys were also determined after exposure at 700 to 1000/sup 0/C for up to 30 000 h. For Incoloy-800H, the results showed good retention of ductility and impact strength. The nickel-base alloys, in contrast, were found to have low room-temperature impact resistance after long time exposure at 700 to 900/sup 0/C, typical values being 10 to 20 J x cm/sup -2/. In impact tests at the exposure temperature, impact strengths were generally above 50 J x cm/sup -2/. At room temperature, allowances in design must be made for the low impact strength of the nickel-base alloys to ensure against brittle fracture. For example, excessive stresses during cooling of components following shutdown should be avoided.

  19. Creep property of carbon and nitrogen free high strength new alloys

    Energy Technology Data Exchange (ETDEWEB)

    Muneki, S., E-mail: ABE.Fujio@nims.go.j [Heat Resistant Design Group, Steel Research Center, National Institute for Materials Science (Japan); Okubo, H.; Abe, F. [Heat Resistant Design Group, Steel Research Center, National Institute for Materials Science (Japan)

    2010-06-15

    The carbon and nitrogen free new alloys which were composed of supersaturated martensitic microstructure with high dislocation density before the creep test have been investigated systematically. These alloys were produced from the new approach which raised creep strength by the utilization of the reverse transformed austenite phase as a matrix and intermetallic compounds such as Laves phase and mu-phase as precipitates during heating before the creep test. It is important that these alloys are independent of any carbides and nitrides as strengthening factors. The high temperature creep test over 700 {sup o}C exceeds 50,000 h, and the test is continuous. Creep behavior of the alloys is found to be different from that of the conventional high-Cr ferritic steels. The addition of boron to the alloy pulled the recrystallization temperature up in the high temperature, and it became a creep test in the un-recrystallization condition, and the creep property of high temperature over 700 {sup o}C was drastically improved. The minimum creep rates of Fe-Ni alloys at 700 {sup o}C are found to be much lower than those of the conventional high Cr ferritic heat resistant steels, which is due to fine dispersion strengthening useful even at 700 {sup o}C in these alloys. As a result it became clear that the value for 100,000 h was exceeded at 700 {sup o}C and 100 MPa calculated from the Larson-Miller parameter at C = 20.

  20. Opportunities and challenges of spray forming high-alloyed steels

    International Nuclear Information System (INIS)

    Spray forming has proven to be a useful tool for generating high-alloyed materials. The metallurgical advantages of high solidification rates are obvious. Shortening of process chains in comparison to powder metallurgy is often discussed. To approach to some of the remaining questions, especially on the influence of process gases on spray forming steels, within this study high-alloyed steels with melt weights up to 150 kg are spray formed and hot worked to semi-finished materials. Properties are analyzed in comparison to products available on the market. Cold-work tool steels with high carbon content can be spray formed to produce materials with good wear resistance and toughness. When reducing the carbon content and the amount of hard carbides, advantage of reduced segregation becomes more apparent. On the other hand, the influence of nitrogen as an alloying element is more effective and means of control are required. When corrosion or heat resistant steels with high non-carbide bonded chromium content or other nitride forming elements are part of the alloy, care has to be taken on controlling the dissolution of process gases and subsequent precipitation and degassing during compaction and further processing. Experiments where melt protection and atomization gas were changed from nitrogen to argon have shown significant influence of process gases on spray forming results and the mechanical properties of the materials in hot worked and finally heat treated conditionorked and finally heat treated condition

  1. Opportunities and challenges of spray forming high-alloyed steels

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, Alwin [Stiftung Institut fuer Werkstofftechnik, Badgasteiner Str. 3, 28359 Bremen (Germany)], E-mail: aschulz@iwt-bremen.de; Uhlenwinkel, Volker [Stiftung Institut fuer Werkstofftechnik, Badgasteiner Str. 3, 28359 Bremen (Germany); Escher, Christoph [Doerrenberg Edelstahl GmbH, Hammerweg 7, 51766 Engelskirchen Ruenderoth (Germany); Kohlmann, Rainer [Edelstahlwerke Suedwestfalen GmbH, TQ-SQ, Postfach 10 12 20, 57012 Siegen (Germany); Kulmburg, Alfred [Technische Universitaet Graz, Institut fuer Werkstoffkunde, Schweisstechnik und Spanlose Formgebungsverfahren, Prangelgasse 12A, 8020 Graz (Austria); Montero, Maria Carmen [Sidenor I-D, S.A., Barrio Ugarte, s/n, Apartado 152, 48970 Basauri (Vizcaya) (Spain); Rabitsch, Roland; Schuetzenhoefer, Wolfgang [Boehler Edelstahl GmbH, R and D, Mariazeller Str. 25, 8605 Kapfenberg (Austria); Stocchi, Domenico [Centro Sviluppo Materiali S.p.A., Via di Castel Romano, 100, 00128 Rome (Italy); Viale, Dominique [Industeel S.A., Centre de Recherche des Materiaux, 56, rue Clemenceau, 71202 Le Creusot Cedex (France)

    2008-03-25

    Spray forming has proven to be a useful tool for generating high-alloyed materials. The metallurgical advantages of high solidification rates are obvious. Shortening of process chains in comparison to powder metallurgy is often discussed. To approach to some of the remaining questions, especially on the influence of process gases on spray forming steels, within this study high-alloyed steels with melt weights up to 150 kg are spray formed and hot worked to semi-finished materials. Properties are analyzed in comparison to products available on the market. Cold-work tool steels with high carbon content can be spray formed to produce materials with good wear resistance and toughness. When reducing the carbon content and the amount of hard carbides, advantage of reduced segregation becomes more apparent. On the other hand, the influence of nitrogen as an alloying element is more effective and means of control are required. When corrosion or heat resistant steels with high non-carbide bonded chromium content or other nitride forming elements are part of the alloy, care has to be taken on controlling the dissolution of process gases and subsequent precipitation and degassing during compaction and further processing. Experiments where melt protection and atomization gas were changed from nitrogen to argon have shown significant influence of process gases on spray forming results and the mechanical properties of the materials in hot worked and finally heat treated condition.

  2. An irradiation test of heat-resistant ceramic composite materials. Interim report on post-irradiation examinations of the first preliminary irradiation test: 97M-13A

    International Nuclear Information System (INIS)

    The Japan Atomic Energy Research Institute (JAERI) has been carrying out the research on radiation damage mechanism of heat-resistant ceramic composite materials, as one of the subjects of the innovative basic research on high temperature engineering using the High Temperature Engineering Test Reactor (HTTR). A series of preliminary irradiation tests is being made using the Japan Materials Testing Reactor (JMTR). The present report describes results of post-irradiation examinations (PIE) so far on specimens irradiated in the first capsule, designated 97M-13A, to fast neutron fluences of 1.2-1.8x1024 m-2 (E>1 MeV) at temperatures of 573, 673 and 843 K. In the PIE, measurements were made on (1) dimensional changes, (2) thermal expansions, (3) X-ray parameters and (4) ?-ray spectra. The results for the carbon/carbon and SiC/SiC composites were similar to those in existing literatures. The temperature monitor effect was observed both for SiC fiber- and particle-reinforced SiC composites as in the case of monolithic SiC. Namely, the curve of the coefficient of thermal expansion (CTE) of these specimens showed a rapid drop above a temperature around the irradiation temperature +100 K in the first ramp (ramp rate: 10 K/min), while in the second ramp the CTE curves were almost the same as those of un-irradiated SiC specimens. (author)

  3. Heat resistance mediated by a new plasmid encoded Clp ATPase, ClpK, as a possible novel mechanism for nosocomial persistence of Klebsiella pneumoniae.

    DEFF Research Database (Denmark)

    Bojer, Martin Saxtorph; Struve, Carsten

    2010-01-01

    Klebsiella pneumoniae is an important opportunistic pathogen and a frequent cause of nosocomial infections. We havecharacterized a K. pneumoniae strain responsible for a series of critical infections in an intensive care unit over a two-year period. The strain was found to be remarkably thermotolerant providing a conceivable explanation of its persistence in the hospital environment. This marked phenotype is mediated by a novel type of Clp ATPase, designated ClpK. The clpK gene is encoded by a conjugative plasmid and we find that the clpK gene alone renders an otherwise sensitive E. coli strain resistant to lethal heat shock. Furthermore, one third of a collection of nosocomial K. pneumoniae isolates carry clpK and exhibit a heat resistant phenotype. The discovery of ClpK as a plasmid encoded factor and its profound impact on thermal stress survival sheds new light on the biological relevance of Clp ATPases in acquired environmental fitness and highlights the challenges of mobile genetic elements in fighting nosocomial infections

  4. Heat Resistance Mediated by a New Plasmid Encoded Clp ATPase, ClpK, as a Possible Novel Mechanism for Nosocomial Persistence of Klebsiella pneumoniae

    DEFF Research Database (Denmark)

    Bojer, Martin Saxtorph; Struve, Carsten

    2010-01-01

    Klebsiella pneumoniae is an important opportunistic pathogen and a frequent cause of nosocomial infections. We have characterized a K. pneumoniae strain responsible for a series of critical infections in an intensive care unit over a two-year period. The strain was found to be remarkably thermotolerant providing a conceivable explanation of its persistence in the hospital environment. This marked phenotype is mediated by a novel type of Clp ATPase, designated ClpK. The clpK gene is encoded by a conjugative plasmid and we find that the clpK gene alone renders an otherwise sensitive E. coli strain resistant to lethal heat shock. Furthermore, one third of a collection of nosocomial K. pneumoniae isolates carry clpK and exhibit a heat resistant phenotype. The discovery of ClpK as a plasmid encoded factor and its profound impact on thermal stress survival sheds new light on the biological relevance of Clp ATPases in acquired environmental fitness and highlights the challenges of mobile genetic elements in fightingnosocomial infections.

  5. Effects of carbon on creep-rupture strength and toughness of high Cr-Mo heat resisting steels containing V and Nb

    International Nuclear Information System (INIS)

    Effects of carbon on creep-rupture properties and room temperature toughness of high (9 ? 10)Cr-(1.8 ? 2)Mo ferritic heat resisting steels containing V and Nb were studied. The carbon content was varied from 0.02 to 0.23 % in order to improve toughness without decreasing the creep-rupture strength. Difference existing in creep-rupture strength and in Charpy absorbed energy between 10Cr-2Mo steels and 9Cr-1.8Mo steels were studied with respect to the ratio of delta ferrite to martensite, the precipitates, and the microstructure. The results indicated that the 9Cr-1.8Mo-0.1V-0.05Nb steels with 0.14 % C tempered at 800 deg C showed good toughness, and that 104 h rupture-strength of the steel was as high as that of SUS 316 austenitic stainless steel at 550 deg C and SUS 304 at 600 deg C. It was concluded that the optimum amount of delta ferrite from the point of view of creep-rupture strength and Charpy absorbed energy was 10 ? 20 %. (author)

  6. Effect of microstructural evolution on high-temperature strength of 9Cr–3W–3Co martensitic heat resistant steel under different aging conditions

    International Nuclear Information System (INIS)

    Evolution of microstructures and high-temperature strength at 650 °C of 9Cr–3W–3Co martensitic heat resistant steel after aging at 650 °C and 700 °C for different time durations have been experimentally investigated using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), field emission transmission electron microscopy (FETEM) and post-aged tensile tests. The results show that after aging at 650 °C, the high-temperature strength and the microstructures of 9Cr–3W–3Co steel keep almost stable with increasing aging time from 300 h to 3000 h. In comparison, after aging at 700 °C, there are obvious changes in the high-temperature strength and the microstructures. The strengthening mechanisms of the 9Cr–3W–3Co steel were also discussed and the athermal yield stresses were calculated. The change of the high-temperature strength is mainly affected by the evolution of dislocations and laths. The precipitates mainly act as obstacles against motion of dislocations and lath boundaries

  7. Prevalence of Clostridium botulinum and thermophilic heat-resistant spores in raw carrots and green beans used in French canning industry.

    Science.gov (United States)

    Sevenier, V; Delannoy, S; André, S; Fach, P; Remize, F

    2012-04-16

    Two categories of vegetables (carrots and green beans) that are widely used in the manufacture of canned food were surveyed for their spore contamination. Samples were recovered from 10 manufactures spread over all producing areas in France. Two samples over 316 raw vegetables collected were found positive for botulinum neurotoxin producing Clostridia spores as tested by PCR-based GeneDisc assay. Both positive samplestested positive for the type B neurotoxin gene (bont/B). In parallel, heat-resistant spores of thermophilic bacteria that are likely to be associated with canned food spoilage after prolonged incubation at 55 °C were surveyed after specific enrichment. Prevalence varied between 1.6% for Moorella thermoacetica/thermoautotrophica in green bean samples and 8.6% for either Geobacillus stearothermophilus or Thermoanaerobacterium spp. in carrot samples. Vegetable preparation, e.g. washing and edge cutting, considerably reduced spore contamination levels. These data constitute the first wide examination of vegetables specifically cultivated for industrialpurposes for their contamination by spores of thermophilic bacterial species. PMID:22405945

  8. Microstructures and High-Temperature Mechanical Properties of a Martensitic Heat-Resistant Stainless Steel 403Nb Processed by Thermo-Mechanical Treatment

    Science.gov (United States)

    Chen, Liqing; Zeng, Zhouyu; Zhao, Yang; Zhu, Fuxian; Liu, Xianghua

    2013-11-01

    Thermo-mechanical treatments (TMT) at different rolling deformation temperatures were utilized to process a martensitic heat-resistant stainless steel 403Nb containing 12 wt pct Cr and small additions of Nb and V. Microstructures and mechanical properties at room and elevated temperatures were characterized by scanning electron microscopy, transmission electron microscopy, and hardness, tensile, and creep tests. The results showed that high-temperature mechanical behavior after TMT can be greatly improved and microstructures with refined martensitic lath and finely dispersed nanosized MX carbides could be produced. The particle sizes of M23C6 and MX carbides in 403Nb steel after conventional normalizing and tempering (NT) treatments are about 50 to 160 and 10 to 20 nm, respectively, while those after TMT at 1123 K (850 °C) and subsequent tempering at 923 K (650 °C) for 2 hours reach about 25 to 85 and 5 to 10 nm, respectively. Under the condition of 260 MPa and 873 K (600 °C), the tensile creep rupture life of 403Nb steel after TMT at 1123 K (850 °C) is 455 hours, more than 3 times that after conventional NT processes. The mechanisms for improving mechanical properties at elevated temperature were analyzed in association with the existence of finely dispersed nanosized MX particles within martensitic lath. It is the nanosized MX particles having the higher stability at elevated temperature that assist both dislocation hardening and sub-grain hardening for longer duration by pinning the movement of dislocations and sub-grain boundary migration.

  9. Elevated levels of 70,000 dalton heat shock proteins in transiently thermotolerant Chinese hamster fibroblasts and in their stable heat resistant variants

    International Nuclear Information System (INIS)

    The function of one or more heat shock proteins (HSPs) may be to confer protection to cells against thermal damage. The quantitative relationship between heat sensitivity and concentration of several HSPs in thermotolerant Chinese hamster HA-1 cells and in their stable heat resistant variants (3011 and 2242) were examined. The presence or concentration of low molecular weight HSPs (22-27 kd) showed no correlation with cell survival after heat shock. In contrast, the concentration of 70 kd HSP correlated well with the logarithm of cell survival. To summarize, the data indicate that if any of the HSPs is indeed responsible for providing protection against heat-induced cell death, then the 70 kd HSP is the most likely candidate. It is not the rate of synthesis that is of importance, but the absolute level of this HSP. Furthermore, it does not matter whether the protein is induced in response to an earlier heat shock or is present in constitutive form. In either case the level of 70 kd HSP appears to be a good predictor of heat response

  10. Fuel behavior in severe accidents and Mo-alloy based cladding designs to improve accident tolerance

    International Nuclear Information System (INIS)

    The severe accidents at TMI-2 and Fukushima-Daiichi led to core meltdown and hydrogen explosions. The main source of energy causing core melting is the decay heat from ?-, ?+, and ? decays of short-lived isotopes following a power scram. The exothermic reaction of Zr-alloy cladding can further increase the cladding temperature leading to rapid cladding corrosion and hydrogen production. The most effective mitigation to minimize core damage in a severe accident is to extend the duration of heat removal capacity via battery-supported passive cooling for as long as practically possible. Replacing the Zr-alloy cladding with a higher heat resistant cladding with lower enthalpy release rate may also provide additional coping time for accident management. Such a heat resistant cladding may also overcome the current licensing concerns about Zr-alloy hydriding and post quench ductility issues in a design base loss of coolant accident (LOCA). Zr-alloy cladding, while has been optimized for normal operation in high pressure water and steam of light water reactors, will rapidly lose its corrosion resistance and tensile and creep strength in high pressure steam. Evaluation of alternate cladding materials and designs have been performed to search for a new fuel cladding design which will substantially improve the safety margins at elevated temperatures during a severe accident, while maintaining the excellent fuel performance attributes of the current Zr-alloy cladding. The screthe current Zr-alloy cladding. The screening criteria for the evaluation include neutronic properties, material availability, adaptability and operability in current LWRs, resistance to melting. The new designs also need to be fabricable, maintain sufficient strength and resist to attack by high pressure steam. Engineering metals, alloys and ceramics which can meet some or most of these requirements are limited. Following review of the properties of potential candidates, it is concluded that molybdenum alloys may potentially achieve the largest improvement in fuel safety margins in a severe accident. To adopt molybdenum alloys for LWR fuel cladding application, a novel design of duplex and triplex Mo-Zr or Mo-advanced steel cladding is proposed as the best candidate for further development. The technical basis for selecting the Mo-Zr cladding out of several other potential candidates, and the approaches to overcome the weakness of the molybdenum alloys are discussed. (orig.)

  11. Interrelation between strength and creep in niobium base alloys

    International Nuclear Information System (INIS)

    The common analysis of experimental data on high-temperature mechanical properties of low- and medium-alloyed niobium melts in the vacuum-arc melting of the Nb-W-Mo-Zr system and in the recrystallized and cast states under the conditions of single-axis tension is carried out. There exist close correlation bonds between the characteristics of short-term, continuous static strength, plasticity and creep resistance for the studied materials in the high-temperature area. Both partial and generalized empiric dependence, binding the melts heat-resistance indices with their time resistance and relative elongation and short-time static tension, independent of the materials structural state and destruction character, are obtained

  12. Determination of the alloyed amount of cerium and microdistribution of cerium in steel, cast iron and aluminium by radioassay and autoradiography

    International Nuclear Information System (INIS)

    An experimental method for the determination of the amount of rare earth alloyed in steel, cast iron, aluminium and its alloy and a coating-autoradiography technique have been developed. Microautoradiographs show that the cerium is distributed in the grains, but cerium mainly segregates along the grain boundaries and dendrite boundaries of aluminium, Al-Mg alloys and heat-resisting Fe-Cr-Al alloys. Cerium contained in the pearlite is more than that in the ferrite of 16Mn and 25MnTiB steels. There is little cerium in the ferrite and pearlite which surround the spheroidal graphite, while in the pearlite and ledeburite which are located far from the spheroidal graphite there is much cerium. Cerium is distributed uniformly in flake graphite, while it is distributed in various ways in spheroidal graphite. (orig.)

  13. Influence of carburisation on the room temperature tensile properties of high temperature alloys

    International Nuclear Information System (INIS)

    A series of doctoral and diploma investigations which have been carried out at the Institute of Reactor Materials of the KFA are reported. The influence of both thermal exposure and carburisation at 8000C and above on the room temperature tensile properties of Incoloy 800 H, Inconel 617, Hastelloy X and Nimonic 86 has been studied and the results have been compared with literature data. It is shown that the room temperature ductility of Incoloy 800 H is much less sensitive to carburisation than that of the nickel-base alloys. This is attributed to the greater volume fraction of carbide formed in the nickelbase alloys for a particular bulk carbon content. In the nickel-base alloys carbide volume fractions are higher than in iron-base alloys due to the lower solubility of carbon and to the formation of M6C carbides. The ductility of reformer and intermediate heat exchanger (IHX) tubes after long service times in a process heat high temperature reactor has been estimated using carburisation rates found in corrosion experiments. The data indicate that a reformer tube of Incoloy 800 H should retain a room temperature ductility equivalent to 5% tensile elongation - a normal minimum requirement in conventional engineering design - over the anticipated service life of 140000 h. For the IHX tubes, the impurity concentrations in the primary coolant must be carefully controlled in order to avoid embrittlement by carburisation. Alternatively, a design concepburisation. Alternatively, a design concept to allow the use of low ductility tubes will be required. Suggestions are given for future work, in particular for alloy development to produce alloys which are less severely embrittled by carburisation. (orig.)

  14. Influence of carburisation on the room temperature tensile properties of high temperature alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ennis, P.J.; Lupton, D.F.; Nickel, H.; Schuster, H.

    1982-05-01

    A series of doctoral and diploma investigations which have been carried out at the Institute of Reactor Materials of the KFA are reported. The influence of both thermal exposure and carburisation at 800/sup 0/C and above on the room temperature tensile properties of Incoloy 800 H, Inconel 617, Hastelloy X and Nimonic 86 has been studied and the results have been compared with literature data. It is shown that the room temperature ductility of Incoloy 800 H is much less sensitive to carburisation than that of the nickel-base alloys. This is attributed to the greater volume fraction of carbide formed in the nickel-base alloys for a particular bulk carbon content. In the nickel-base alloys carbide volume fractions are higher than in iron-base alloys due to the lower solubility of carbon and to the formation of M/sub 6/C carbides. The ductility of reformer and intermediate heat exchanger (IHX) tubes after long service times in a process heat high temperature reactor has been estimated using carburisation rates found in corrosion experiments. The data indicate that a reformer tube of Incoloy 800 H should retain a room temperature ductility equivalent to 5% tensile elongation - a normal minimum requirement in conventional engineering design - over the anticipated service life of 140,000 h. For the IHX tubes, the impurity concentrations in the primary coolant must be carefully controlled in order to avoid embrittlement by carburisation. Alternatively, a design concept to allow the use of low ductility tubes will be required. Suggestions are given for future work, in particular for alloy development to produce alloys which are less severely embrittled by carburisation.

  15. Chemical analysis of nickel- and iron-base high-temperature alloys for nuclear reactor

    International Nuclear Information System (INIS)

    The Committee studied problems in analysis of alloys used for High-Temperature Gas Cooled Reactor from September 1970 to February 1976. The alloys selected from the standpoint of analytical chemistry are Inconel 600, Incoloy 800, Inconel X750, Inco 713C and Hastelloy X. Nine standard samples (JAERI-R 1 to JAERI-R 9) of the high-temperature alloys were prepared primarily for X-ray fluorescence method. Eighteen research institutions in Japan participated in cooperative analyses of the standard samples for 19 elements (C, Si, Mn, P, S, Ni, Cr, Fe, Mo, Cu, W, V, Co, Ti, Al, B, Nb, Ta, Zr). Prior to analyses of the standard samples, 8 cooperative samples (A-H) were analyzed to develop and evaluate analytical methods. Described in this report are preparation and their characteristics of the standard samples, results of analyses, and 93 analytical methods. The results of the cooperative experiments on atomic absorption spectrophotometry and X-ray fluorescence method are also described. (auth.)

  16. Technology readiness level (TRL) assessment of cladding alloys for advanced nuclear fuels

    International Nuclear Information System (INIS)

    Reliable fuel claddings are essential for the safe, sustainable and economic operation of nuclear stations. This paper presents a worldwide TRL assessment of advanced claddings for Gen III and IV reactors following an extensive literature review. Claddings include austenitic, ferritic/martensitic (F/M), reduced activation (RA) and oxide dispersion strengthened (ODS) steels as well as advanced iron-based alloys (Kanthal alloys). Also assessed are alloys of zirconium, nickel (including HastelloyR), titanium, chromium, vanadium and refractory metals (Nb, Mo, Ta and W). Comparison is made with Cf/C and SiCf/SiC composites, MAX phase ceramics, cermets and TRISO fuel particle coatings. The results show in general that the higher the maximum operating temperature of the cladding, the lower the TRL. Advanced claddings were found to have lower TRLs than the corresponding fuel materials, and therefore may be the limiting factor in the deployment of advanced fuels and even possibly the entire reactor in the case of Gen IV. (authors)

  17. Some peculiarities of arc welding of heat pipes of the Kh28N48V5 cast alloy

    International Nuclear Information System (INIS)

    Use of argon-electric arc welding of radiation pipes made it possible to considerably improve the strength of the welding joint and provide uninterrupted operation of thermal furnaces at the Pervouralsk Novotrubny Works. The method was applied in welding U-pipes consisting of a heat-resistant alloy, Kh28N48B5, suitable for making new and for repairing spent pipes of this type. For the first layer - GSl and for the second layer - OZL-31, electrodes were used with reversed polarity d.c. under conditions involving preheating of the welding spot to 600-700 deg C

  18. Effect of temperature on corrosion resistance and electrochemical behaviour of steels and alloys in red fuming nitric acid

    International Nuclear Information System (INIS)

    Methodology for studying metal corrosion in red fuming nitric acid at high temperatures is developed and data on corrosion rate of stainless steels and heat-resistant alloys at 50-450 C are obtained. It is established that corrosion rate at 200 C (while the system is in condensed state) sharply grows with temperature increase and decreases at 300-450 C: products in form of scale are formed. Facility for studying metal electrochemical characteristics in aggressive media at high temperatures is developed. It is shown that increase in temperature decreases the passivation aired and reduces repassivation potential while increasing current in the passive aired. Refs. 30, figs. 9

  19. Phase equilibria in Ni-TiC-MeC (Me: Zr, Hf, Nb, Ta) system alloys

    International Nuclear Information System (INIS)

    Phase equilibria in heat resisting Ni-TiC-MeC(MeZr, Hf, Nb, Ta) system alloys were investigated. Metalographic analysis was used to study cast and annealed alloys. Phase equilibria diagram of Ni-TiC-ZrC system posesses one ternary eutectic melting at the temperature of 1175+-15 deg C and containing 6+-0.7 mol.% TiC and 4+-0.7 mol % ZrC. Two carbide phases are formed in this system alloys which composition corresponds to the position of solid solution binodal decomposition curve in quasibinary TiC-ZrC system. The state diagram of Ni-TiC-HfC system is similar to the one of Ni-TiC-ZrC system. Cast alloys of this system show a tendency to crystallizationin metastable state when carbide phase doesn't decompose into two solid solutions. In Ni-TiC-TaC system alloys carbide phase doesn't decompose even during annealing (1000 deg C, 10 hours). State diagrams of these systems possess one monovariant eutectic. When obtaining carbide phases using metallic bath the most reliable results are received when alloys with eutectic compositions are used

  20. Thermophilic spore-forming bacteria isolated from spoiled canned food and their heat resistance. Results of a French ten-year survey.

    Science.gov (United States)

    André, S; Zuber, F; Remize, F

    2013-07-15

    Thermal processing of Low Acid Canned Foods (LACF), which are safe and shelf-stable at ambient temperature for several years, results in heat inactivation of all vegetative microorganisms and the partial or total inactivation of spores. Good Manufacturing Hygienic Practices include stability tests for managing the pathogen risk related to surviving mesophilic bacterial spores. LACF are also often submitted to additional incubation conditions, typically 55 °C for 7 days, to monitor spoilage by thermophiles. In this study we identified the bacterial species responsible for non-stability after prolonged at 55 °C of incubation of LACF from 455 samples collected from 122 French canneries over 10 years. Bacteria were identified by microsequencing or a recent developed tool for group-specific PCR detection (SporeTraQ™). A single species was identified for 93% of examined samples. Three genera were responsible for more than 80% of all non-stability cases: mostly Moorella (36%) and Geobacillus (35%), and less frequently Thermoanaerobacterium (10%). The other most frequent bacterial genera identified were Bacillus, Thermoanaerobacter, Caldanaerobius, Anoxybacillus, Paenibacillus and Clostridium. Species frequency was dependent on food category, i.e. vegetables, ready-made meals containing meat, seafood or other recipes, products containing fatty duck, and related to the intensity of the thermal treatment applied in these food categories. The spore heat resistance parameters (D or ? and z values) from 36 strains isolated in this study were determined. Taken together, our results single out the species most suitable for use as indicators for thermal process settings. This extensively-documented survey of the species that cause non-stability at 55 °C in LACF will help canneries to improve the management of microbial contamination. PMID:23728430

  1. Inactivation of chemical and heat-resistant spores of Bacillus and Geobacillus by nitrogen cold atmospheric plasma evokes distinct changes in morphology and integrity of spores.

    Science.gov (United States)

    van Bokhorst-van de Veen, Hermien; Xie, Houyu; Esveld, Erik; Abee, Tjakko; Mastwijk, Hennie; Nierop Groot, Masja

    2015-02-01

    Bacterial spores are resistant to severe conditions and form a challenge to eradicate from food or food packaging material. Cold atmospheric plasma (CAP) treatment is receiving more attention as potential sterilization method at relatively mild conditions but the exact mechanism of inactivation is still not fully understood. In this study, the biocidal effect by nitrogen CAP was determined for chemical (hypochlorite and hydrogen peroxide), physical (UV) and heat-resistant spores. The three different sporeformers used are Bacillus cereus a food-borne pathogen, and Bacillus atrophaeus and Geobacillus stearothermophilus that are used as biological indicators for validation of chemical sterilization and thermal processes, respectively. The different spores showed variation in their degree of inactivation by applied heat, hypochlorite, hydrogen peroxide, and UV treatments, whereas similar inactivation results were obtained with the different spores treated with nitrogen CAP. G. stearothermophilus spores displayed high resistance to heat, hypochlorite, hydrogen peroxide, while for UV treatment B. atrophaeus spores are most tolerant. Scanning electron microscopy analysis revealed distinct morphological changes for nitrogen CAP-treated B. cereus spores including etching effects and the appearance of rough spore surfaces, whereas morphology of spores treated with heat or disinfectants showed no such changes. Moreover, microscopy analysis revealed CAP-exposed B. cereus spores to turn phase grey conceivably because of water influx indicating damage of the spores, a phenomenon that was not observed for non-treated spores. In addition, data are supplied that exclude UV radiation as determinant of antimicrobial activity of nitrogen CAP. Overall, this study shows that nitrogen CAP treatment has a biocidal effect on selected Bacillus and Geobacillus spores associated with alterations in spore surface morphology and loss of spore integrity. PMID:25481059

  2. Brazing of C/C composites and Ni-based alloy using interlayer

    Science.gov (United States)

    Ikeshoji, Toshi-Taka; Tokunaga, Tatsuya; Suzumura, Akio; Yamazaki, Takahisa

    2014-08-01

    The brazing of C/C composites and Inconel-600 Ni-based heat resistant alloy was conducted using Fe-Ni-Cr-P-Si brazing filler alloy with inserting various thickness of Nb foil as stress relief interlayer. SEM observation of cross section of brazing interface revealed that Nb foil was resolved into the brazing filler layer on C/C composites side. Nb diffused to the surface of C/C composites and acted as the active metal element to enhance the wettability of molten metal on graphite matrix of C/C composites during the brazing process. The variation in shear strength values of the brazed joint with Nb layer thickness suggested that the Nb layer should be remained at least 100 ?m.

  3. Pilot-plant production the EhI893 VD alloy

    International Nuclear Information System (INIS)

    Tested was the commercial production of heat resisting EhI893 VD nickel base alloy by the method of vacuum-arc melt (VAM). Investigated were its structure, short-term mechanical properties, long-term and fatigue strength on the metal samples of ingots, 105 mm in diameter rods and the stamping billets of turbine blades. Metallographic investigations of the liquation zones and the main structure of ingots showed, that OI melt (open induction) and VA melt metals (vacuum-arc) were the same according to the chemical and phase composition. It was stated, that EhI893 VD alloy had a high level of strength and ductility properties both at the room temperature and at 750 deg C

  4. Elevated temperature aluminum alloys

    Science.gov (United States)

    Meschter, Peter (Inventor); Lederich, Richard J. (Inventor); O'Neal, James E. (Inventor)

    1989-01-01

    Three aluminum-lithium alloys are provided for high performance aircraft structures and engines. All three alloys contain 3 wt % copper, 2 wt % lithium, 1 wt % magnesium, and 0.2 wt % zirconium. Alloy 1 has no further alloying elements. Alloy 2 has the addition of 1 wt % iron and 1 wt % nickel. Alloy 3 has the addition of 1.6 wt % chromium to the shared alloy composition of the three alloys. The balance of the three alloys, except for incidentql impurities, is aluminum. These alloys have low densities and improved strengths at temperatures up to 260.degree. C. for long periods of time.

  5. Sheet production using powder rolling of nickel and titanium alloys

    International Nuclear Information System (INIS)

    Based on information contained in literature, patents and catalogs a review is presented of powder-rolling metallurgy abroad. Statistics are given on the output of powder metallurgy in several countries. In the USA both the dense type of rolled metal for manufacturing various machine parts and the porous variety for making filters are produced. Four main types of technological processes are analysed: the usual flow chart for cold rolling, rolling of preheated powder, rolling in free-flowing state, and rolling with heated rollers. Of these four processes the first is most widely used. Fowders consisting of spherical particles (heat-stable alloys from nickel or high titanium alloys), which are difficult to work with, have not yet found wide practical application in powder metallurgy abroad. Literature data show that granulated heat-resistant alloys can be cold-treated under pressure only after they are powdered. The best methods for pulverizing are: cold-stream granulation and grinding with the aid of vibrational mills. Vacuum rolling of powders and rolling with electrically preheated rollers are especially promising in rolling powders that are difficult to deform

  6. Superconducting alloys

    International Nuclear Information System (INIS)

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

  7. VAl Alloy

    Science.gov (United States)

    Mikami, M.; Mizoshiri, M.; Ozaki, K.; Takazawa, H.; Yamamoto, A.; Terazawa, Y.; Takeuchi, T.

    2014-06-01

    Power generation performance of a thermoelectric module consisting of the Heusler Fe2VAl alloy was evaluated. For construction of the module, W-doped Fe2VAl alloys were prepared using powder metallurgy process. Power generation tests of the module consisting of 18 pairs of p- n junctions were conducted on a heat source of 373-673 K in vacuum. The reduction of thermal conductivity and improvement of thermoelectric figure of merit by W-doping enhanced the conversion efficiency and the output power. High output power density of 0.7 W/cm2 was obtained by virtue of the high thermoelectric power factor of the Heusler alloy. The module exhibited good durability, and the relatively high output power was maintained after temperature cycling test in air.

  8. Orthodontic silver brazing alloys.

    Science.gov (United States)

    Brockhurst, P J; Pham, H L

    1989-10-01

    Orthodontic silver brazing alloys suffer from the presence of cadmium, excessive flow temperatures, and crevice corrosion on stainless steel. Seven alloys were examined. Two alloys contained cadmium. The lowest flow temperature observed was 629 degrees C for a cadmium alloy and 651 degrees C for two cadmium free alloys. Three alloys had corrosion resistance superior to the other solders. Addition of low melting temperature elements gallium and indium reduced flow temperature in some cases but produced brittleness in the brazing alloy. PMID:2576971

  9. Present-day state of rhenium problem and new directions in the developing rhenium alloys

    International Nuclear Information System (INIS)

    The present state of the metallography of rhenium is characterized by theoretical achievements in the field of binary and ternary state diagrams and ''composition-property'' diagrams for rhenium with various elements of periodic system. Altogether, about 100 state diagrams have been plotted. The different scientific aspects of mechanism of rhenium effect and the mechanism of work hardening of rhenium and its alloys are studied. A number of multi-purpose vacuum-melted and metal-ceramic alloys is developed. The alloys feature specific physical properties meeting the requirements of a number of fields of modern technology and provide for the improved durability and reliability of devices, as well as the development of new structures. A technology is developed and commercial production is organized of products and semifinished products of different ranges from rhenium alloys: rods, wires, foils, belts, etc. The basic trends of further investigations in the field of rhenium metallography are described. The basic attention should be paid to the search for vibration-resistant materials; especially heat resistant under statical and thermocycled loading; cathod-type; wear-resistant; corrosion-resistant; especially durable elastic materials; resistance alloys in the form of thin films for micro-circuits, etc. The basic fields of rhenium employment are electronics, electric engineering, special-purpose devices and other technologies. (author)thor)

  10. Modifying structure and properties of nickel alloys by nanostructured composite powders

    Science.gov (United States)

    Cherepanov, A. N.; Ovcharenko, V. E.; Liu, G.; Cao, L.

    2015-01-01

    The article presents the results of an experimental study of the influence of powder nanomodifiers of refractory compounds on the mechanical properties, macro- and microstructure of heat-resistant alloys ZhS-6K and Inconel 718. It is shown that the introduction of nanomodifiers into the melt leads to the refinement of the alloy structure: the average grain size decreases 1.5-2 times, and their morphology becomes similar to equiaxial at significant reduction of the particle size in the carbide phase. The service life of ZhS-6K alloy under cyclic loading at 600°C increases 2.7 times, and at 975 °C by 40 %, and relative elongation increases more than twice. The mechanical properties of Inconel 718 significantly increase: long-term strength at 650 °C increases 1.5-2 times, and the number of cycles before the collapse at 482 °C grows more than three times. It has been found out that addition of nanomodifiers to the melt, in alloys, forms clusters of particles of refractory compounds at borders and joints of the formed grain structure that may help slowing down the processes of recrystallization (prevents the increase in the size of the contacting grains by their associations) and stabilizes the strength properties of the alloys at higher temperatures.

  11. Mechanical long-term properties of nickel-base alloys for steam turbine bolting

    International Nuclear Information System (INIS)

    Within the reported project three heat resistant nickel-base alloys, Alloy 70 (NiCr 20 Fe 25 TiAl), Alloy 80A (NiCr 20 TiAl) and Alloy X-750 (NiCr 15 TiAl) were investigated for the application to steam turbine bolting in the temperature range of 450 to 600deg C. Important mechanical long-term properties as creep-rupture strength, relaxations strength and contraction were determined to improve the basis for the optimum selection of bolting materials. On the optimized condition of the three materials, some important interdependencies between different mechanical properties were investigated. Using creep and contraction data, it was possible to predict the time-dependent residual stress of the continuous relaxation test with sufficient accuracy. An inelastic finite element calculation of notched specimens of Alloy 80A for 550deg C short-term creep-rupture tests showed, that even under elastoplastic loading there is a risk to crack initiation in the vicinity of the notch. (orig./RHM) With 17 figs., 15 tabs

  12. Phase and structural transformations in the Ni65Mo20Cr15 alloy at changing the temperature of heat treatment

    International Nuclear Information System (INIS)

    Highlights: • Crystalline Mo particles are formed in liquid alloy as a result of phase separation. • Below 1200 °C the high-dispersed phase separation structure forms in the Ni/Cr pair. • Below 1200 °C the Mo particles are dissolved in the Ni/Mo diffusional couple. • Prolonged 650 °C aging causes the Ni2Mo formation in boundaries and embrittlement. -- Abstract: The ternary Ni65Mo20Cr15 alloy was studied using TEM after heat treatment at different temperatures. It has been shown that the tendency to phase separation which exists in the Ni/Mo diffusion couple at high temperatures leads to precipitation of crystalline particles of Mo atoms in the liquid solution. At lowering the heat treatment temperature to 1200 °C, a phase transition ordering – phase separation occurs in the Ni/Mo diffusion couple, which results in dissolution of the particles of Mo atoms. At 650 °C, there takes place precipitation of Ni2Mo phase particles, which can initiate intercrystalline embrittlement of Hastelloy-type alloys

  13. Amorphous alloys for brazing copper based alloys

    International Nuclear Information System (INIS)

    Silver based alloys are used widely when brazing copper based alloys. Due to its high cost, researchers try to obtain silver free brazing alloys, in the shape of amorphous structure ribbons, avoiding thus the formation of intermetallic compounds that diminish its ductility and plasticity. In this paper, the authors present their results in trying to obtain brazing alloys from the Cu-Zn-Ni-P family, ribbon shaped with amorphous structure, using the melt spinning method. The amorphous character of the processed alloy is emphasized by X-Ray diffraction, and the brazed joints made with the alloy were submitted to metallographic analysis and shearing tests.

  14. Studies on improving compatability of nickel-base alloys with a high-temperature helium-cooled reactor (VHTR)

    International Nuclear Information System (INIS)

    Studies on the influence of minor elements on corrosion behaviour of a nickel base heat-resisting alloy have lead to the development of a new alloy specification that is better adopted to long-time service in HTR environment. The principle developed is associated with the promotion of the protective function of oxide film by giving more Mn to form MnCr2O4 spinel layer covering the underlying Cr2O3, optimizing Si for increased oxide adherence by SiO2 patches at oxide/metal interface and preventing intergranular attack by avoiding Al, the deoxidation residue. The same methodology was demonstrated to be valid for other Ni-based superalloys. (author)

  15. Determination of optimum grain size in KhN67MVTYu alloy taking into account main operating parameters

    International Nuclear Information System (INIS)

    An attempt is made to establish a dependence of optimum grain size (dsub(opt)) providing the maximum heat resistance of the KhN67MVTYu alloy on basic operational parameters: temperature (+) and duration of service (tau) in the range from 600 to 900 deg C and the time to rupture values from 0.1 to 1000 h. Dependences dsub(opt)=f(t, tau), analogous in character, have been obtained for the 12Kh25N16GAR steel and KhN78T alloy, however, in narrower range of temperatures and time to rupture values. Obtained formulae have limited application, because they do not take into consideration the state of grain boundaries, character of distribution and dispersity of strengthening phase

  16. Corrosion resistance of Ni-Cr-Mo alloys. Chemical composition and metallurgical condition's effects

    International Nuclear Information System (INIS)

    Ni-Cr-Mo alloys offer an outstanding corrosion resistance in a wide variety of highly-corrosive environments. This versatility is due to the excellent performance of nickel in hot alkaline solutions and the beneficial effect of chromium and molybdenum in oxidizing and reducing conditions, respectively. Alloy C-22 (22 % Cr-13 % Mo-3% W) is a well known versatile member of this family. Due to its excellent corrosion resistance in a wide variety of environments, Alloy C-22 has been selected for the fabrication of the corrosion-resistant outer shell of the high-level nuclear waste container. The increasing demand of the industry for corrosion resistant alloys with particular properties of corrosion and mechanical resistance has led to the development of new alloys. Alloy C-22HS (Ni-21 % Cr-17 % Mo) is a new high-strength corrosion resistant material recently developed and introduced into the market. This alloy provides a corrosion resistance comparable with that of other C-type alloys, and it can also be age hardened to effectively double its yield strength. HASTELLOY HYBRID-BC1 (Ni-22 % Mo-15 % Cr) is a new development intended for filling the gap between Ni-Mo and Ni-Cr-Mo alloys. This novel alloy is able to withstand HCl and H2SO4, even in the presence of dissolved oxygen and other oxidizing species. Its resistance to chloride-induced pitting corrosion, crevice corrosion and stress corrosion cracking is also remarkable. Thermal aging of Ni-Cr-Mo alloys leads to microstructure changes depending on the temperature range and exposure time at temperature. A Long Range Ordering (LRO) reaction can occur in the range of 350 C degrees to 600 C degrees, producing an ordered Ni2(Cr,Mo) phase. This ordering reaction does not seem to affect the corrosion resistance and produces only a slight loss in ductility. LRO transformation is homogeneous and has proven to be useful to fabricate the age-hard enable Alloy C22-HS. Tetrahedral Close Packed (TCP) phases, like ?, ? and P, may form if Ni-Cr-Mo alloys are exposed for tens of hours in the range of 600 C degrees to 1100 C degrees. These phases could have a detrimental effect upon corrosion resistance and cause a loss of mechanical ductility. The precipitation of TCP phases starts at grain boundaries and for long aging times it progresses to twins boundaries and then the grain bodies. TCP phases are rich in Mo and Cr. Zones in the matrix adjacent to the TCP precipitates may be depleted of Cr and Mo, and the alloy becomes sensitized.The aim of the present work was to compare the general corrosion rate and the crevice corrosion susceptibility of alloys C-22, C-22HS and HYBRID-BC1 in different metallurgical conditions when exposed to hot chloride solutions. The effects of the alloy composition and different heat treatments were assessed. (author)

  17. Ferroelectric and ferromagnetic properties of epitaxial BiFeO{sub 3}-BiMnO{sub 3} films on ion-beam-assisted deposited TiN buffered flexible Hastelloy

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, J., E-mail: jiexiong@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Los Alamos National Laboratory, Center for Integrated Nanotechnologies, Division of Materials Physics and Applications, Los Alamos, New Mexico 87545 (United States); Matias, V.; Jia, Q. X. [Los Alamos National Laboratory, Center for Integrated Nanotechnologies, Division of Materials Physics and Applications, Los Alamos, New Mexico 87545 (United States); Tao, B. W.; Li, Y. R. [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China)

    2014-05-07

    Growth of multifunctional thin films on flexible substrates is of great technological significance since such a platform is needed for flexible electronics. In this study, we report the growth of biaxially aligned (BiFeO{sub 3}){sub 0.5}:(BiMnO{sub 3}){sub 0.5} [BFO-BMO] films on polycrystalline Hastelloy by using a biaxially aligned TiN as a seed layer deposited by ion-beam-assisted deposited and a La{sub 0.7}Sr{sub 0.3}MnO{sub 3} (LSMO) as a buffer layer deposited by pulsed laser deposition. The LSMO is used not only as a buffer layer but also as the bottom electrode of the BFO-BMO films. X-ray diffraction showed that the BFO-BMO films are biaxially oriented along both in-plane and out-of-plane directions. The BFO-BMO films on flexible metal substrates showed a polarization of 22.9??C/cm{sup 2}. The magnetization of the BFO-BMO/LSMO is 62?emu/cc at room temperature.

  18. Ferroelectric and ferromagnetic properties of epitaxial BiFeO3-BiMnO3 films on ion-beam-assisted deposited TiN buffered flexible Hastelloy

    International Nuclear Information System (INIS)

    Growth of multifunctional thin films on flexible substrates is of great technological significance since such a platform is needed for flexible electronics. In this study, we report the growth of biaxially aligned (BiFeO3)0.5:(BiMnO3)0.5 [BFO-BMO] films on polycrystalline Hastelloy by using a biaxially aligned TiN as a seed layer deposited by ion-beam-assisted deposited and a La0.7Sr0.3MnO3 (LSMO) as a buffer layer deposited by pulsed laser deposition. The LSMO is used not only as a buffer layer but also as the bottom electrode of the BFO-BMO films. X-ray diffraction showed that the BFO-BMO films are biaxially oriented along both in-plane and out-of-plane directions. The BFO-BMO films on flexible metal substrates showed a polarization of 22.9??C/cm2. The magnetization of the BFO-BMO/LSMO is 62?emu/cc at room temperature

  19. Ferroelectric and ferromagnetic properties of epitaxial BiFeO3-BiMnO3 films on ion-beam-assisted deposited TiN buffered flexible Hastelloy

    Science.gov (United States)

    Xiong, J.; Matias, V.; Tao, B. W.; Li, Y. R.; Jia, Q. X.

    2014-05-01

    Growth of multifunctional thin films on flexible substrates is of great technological significance since such a platform is needed for flexible electronics. In this study, we report the growth of biaxially aligned (BiFeO3)0.5:(BiMnO3)0.5 [BFO-BMO] films on polycrystalline Hastelloy by using a biaxially aligned TiN as a seed layer deposited by ion-beam-assisted deposited and a La0.7Sr0.3MnO3 (LSMO) as a buffer layer deposited by pulsed laser deposition. The LSMO is used not only as a buffer layer but also as the bottom electrode of the BFO-BMO films. X-ray diffraction showed that the BFO-BMO films are biaxially oriented along both in-plane and out-of-plane directions. The BFO-BMO films on flexible metal substrates showed a polarization of 22.9 ?C/cm2. The magnetization of the BFO-BMO/LSMO is 62 emu/cc at room temperature.

  20. A study on fretting fatigue life in elevated temperature for Inconel 600 alloy

    International Nuclear Information System (INIS)

    The safety needs in the operation of nuclear power plant facilities have been increased due to the high temperature and pressure operation conditions within these facilities. Several reports exist on the fretting occurring in the materials of steam generator tubes used in nuclear power plants, which leads to a lower service life. The Inconel 600 alloy, used in steam generator tubes, is a type of nickel-chromium based heat resistant alloy. However, it is necessary to establish a systematic database to guarantee its integrity because there are few data indicating fretting fatigue behaviors at both room and high temperature conditions for the Inconel 600 alloy. Thus, this study analyzed the change in the fatigue characteristics of the Inconel 600 alloy under fretting fatigue by applying plain and fretting fatigue tests at 320 .deg. C, which is the room and actual operating temperature applied to the materials of steam generator tubes. In addition, this study measured the change in the friction force for repetitive cycles in fretting fatigue tests and analyzed the mechanism of fretting fatigue by observing the fracture surfaces.

  1. Effect of coating and surface modification on the corrosion resistance of selected alloys in supercritical water

    International Nuclear Information System (INIS)

    Materials selection is one of the key tasks in Gen-IV reactor development. There is no known material that can meet the expected core outlet conditions of the Canadian SCWR concept (625oC core outlet temperature). High-Cr steels with excellent corrosion resistance are often susceptible to embrittlement due to the precipitation of sigma and other phases in the microstructure. Low-Cr steels such as P91 and oxide dispersion strengthened (ODS) steels exhibit good high-temperature mechanical properties, but the lack of sufficient Cr content makes this group alloy corrode too fast. Improvement in this alloy is needed in order for it to be considered as a piping construction material. In this report, the development of a metallic coating on a P91 substrate is discussed. Recent effort on selection of in-core cladding alloys has focused on heat-resistant 3xx series stainless steels. These alloys have higher strength at high-temperature ranges, but corrosion and stress-corrosion cracking resistance are a concern. Metallic coating and surface modification are considered as possible solutions to overcome this challenge. The effects of surface modification on the corrosion rate of austenitic steels were also reported in this paper. As-machined surface showed much better corrosion resistance than polished surface and advanced surface analyses showed distinct differences in the nature and the morphology of the surface layer metal. Possible mechanisms for improved corrosion performance are discussed. (author)

  2. Assessment of Embrittlement of VHTR Structural Alloys in Impure Helium Environments

    Energy Technology Data Exchange (ETDEWEB)

    Crone, Wendy; Cao, Guoping; Sridhara, Kumar

    2013-05-31

    The helium coolant in high-temperature reactors inevitably contains low levels of impurities during steady-state operation, primarily consisting of small amounts of H{sub 2}, H{sub 2}O, CH{sub 4}, CO, CO{sub 2}, and N{sub 2} from a variety of sources in the reactor circuit. These impurities are problematic because they can cause significant long-term corrosion in the structural alloys used in the heat exchangers at elevated temperatures. Currently, the primary candidate materials for intermediate heat exchangers are Alloy 617, Haynes 230, Alloy 800H, and Hastelloy X. This project will evaluate the role of impurities in helium coolant on the stress-assisted grain boundary oxidation and creep crack growth in candidate alloys at elevated temperatures. The project team will: • Evaluate stress-assisted grain boundary oxidation and creep crack initiation and crack growth in the temperature range of 500-850°C in a prototypical helium environment. • Evaluate the effects of oxygen partial pressure on stress-assisted grain boundary oxidation and creep crack growth in impure helium at 500°C, 700°C, and 850°C respectively. • Characterize the microstructure of candidate alloys after long-term exposure to an impure helium environment in order to understand the correlation between stress-assisted grain boundary oxidation, creep crack growth, material composition, and impurities in the helium coolant. • Evaluate grain boundary engineering as a method to mitigate stress-assisted grain boundary oxidation and creep crack growth of candidate alloys in impure helium. The maximum primary helium coolant temperature in the high-temperature reactor is expected to be 850-1,000°C.Corrosion may involve oxidation, carburization, or decarburization mechanisms depending on the temperature, oxygen partial pressure, carbon activity, and alloy composition. These corrosion reactions can substantially affect long-term mechanical properties such as crack- growth rate and fracture toughness, creep rupture, and fatigue. Although there are some studies on the effects of impurities in helium coolant on creep rupture and fatigue strength, very little is known about their effects on creep crack initiation and crack growth rate at elevated temperatures.

  3. Steel alloys

    International Nuclear Information System (INIS)

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

  4. High frequency fatigue test of IN 718 alloy – microstructure and fractography evaluation

    Directory of Open Access Journals (Sweden)

    J. Belan

    2015-01-01

    Full Text Available INCONEL alloy 718 is a high-strength, corrosion-resistant nickel chromium material used at -253 °C to 705 °C for production of heat resistant parts of aero jet engine mostly. The fatigue test provided on this kind materials were done via low frequency loading up to this time. Nowadays, needs of results at higher volume of loading cycles leads to high frequency loading with aim to shorten testing time. Fatigue test of experimental material was carried out at frequency 20 kHz with stress ration R = - 1 (push – pull at room temperature. It was found that this superalloy can still fracture after exceeding 108 cycles. Besides fatigue test were microstructural characterisation and scanning electron microscopy (SEM fractography evaluation done.

  5. A study on fretting fatigue life for the Inconel alloy 600 at high temperature

    International Nuclear Information System (INIS)

    Fatigue tests of the Inconel 600, a type of nickel-chromium based heat resistant alloy used for steam generator tubes in nuclear power plants, were carried out. Temperature increase to 320 oC did not change the fatigue strength much, but the fretting condition caused a significant reduction in the fatigue strength. The reduction at 107 cycles was about 70% for both of room and the high temperatures. An apparatus to realize the fretting condition has been developed and instrumented to measure the normal and friction forces. The bridge type of contact pad was fabricated of SUS 409 stainless steel. Fracture surfaces and wear scars were observed by electron microscope and the profiles of wear scar were measured by non-contact 3D-profiler.

  6. Optimization of the Mg–Al–Zn–Ca–Sr alloy composition based on the parameter A? in the constitutive equation for the climb-controlled dislocation creep including the stacking fault energy

    International Nuclear Information System (INIS)

    In this study, calcium, Ca-, and strontium, Sr-added AZ91 magnesium alloys, which were composed of magnesium, Mg–9 wt.% aluminum, Al–0.8 wt.% zinc, Zn–x wt.% Ca–y wt.% Sr, were formulated and designated as AZXJ91xy alloys. The optimum composition of die-cast AZXJ alloys has been studied by micro-structural analysis and through the application of the constitutive equation of deformation behavior at elevated temperatures that includes the stacking fault energy. The normalized plots of the tensile test results of AZXJ alloys at 448 K by the constitutive equation of deformation behavior indicated that the deformation mechanism of the alloys was climb-controlled dislocation creep. The value of the constant A? in the constitutive equation differs in the different AZXJ alloys, even though the effect of the solid solution of added elements, which is considered in the stacking fault energy term, was eliminated from A?. Using A? as an indicator parameter of the creep resistance with the tensile strength at ambient temperature, the optimum composition of the creep-resistant Mg–Al–Zn–Ca–Sr alloy has been determined, and its creep resistance was comparable to those of known heat-resistant magnesium alloys.

  7. Identificação de cultivares de milho, feijão, algodão e soja por meio de enzimas e proteínas resistentes ao calor / Cultivars identification of corn, bean, cotton and soybean using enzymes and heat-resistant proteins

    Scientific Electronic Library Online (English)

    Mariney de, Menezes; Édila Vilela de Resende Von, Pinho; Antônio Marcos de Andrade Rezende, Pereira; João Almir de, Oliveira.

    Full Text Available Nesta pesquisa foram avaliados o polimorfismo e a estabilidade de isoenzimas e de proteínas resistentes ao calor em sementes de cultivares de milho, feijão, algodão e soja, com diferentes níveis de qualidade fisiológica. As isoenzimas ,álcool desidrogenase, catalase, esterase e superóxido dismutase [...] analisadas conjuntamente, foram eficientes na separação de oito cultivares de milho. Para as cultivares de feijão, pela enzima peroxidase foi possível diferenciar a cultivar Carioca, no entanto, este padrão mostrou-se variável em sementes com baixa germinação. Não foi possível diferenciar as cultivares de algodão pelas enzimas esterase, superóxido dismutase, diaforase e malato desidrogenase. A cultivar Conquista, de soja, foi diferenciada pelos sistemas enzimáticos esterase e superóxido dismutase e a 'BRS-154' pela esterase. Proteínas resistentes ao calor são polimórficas e estáveis para a identificação de cultivares de milho. Abstract in english In this study the polymorphism and stability of isoenzymes and heat-resistant proteins in corn, bean, cotton, and soybean seeds with different levels of physiological quality were evaluated. The alcohol dehydrogenase, catalase, esterase and superoxide dismutase enzymes and simultaneous analysis were [...] effective in identifying eight corn cultivars. It was observed for the bean cultivars that the peroxidase enzyme allowed differentiation of the Carioca bean cultivar from the others but, the peroxidase enzyme pattern varied in seeds with low-germination percentage. The varieties of cotton could not be differentiated by esterase enzyme, superoxide dismutase, diaphorase and malate dehydrogenase. The Conquista soybean cultivar was separated by superoxide dismutase and esterase enzyme systems and BRS-154 was separated by esterase. Heat-resistant protein patterns showed polymorphism and were stable for corn cultivar identification.

  8. Identificação de cultivares de milho, feijão, algodão e soja por meio de enzimas e proteínas resistentes ao calor Cultivars identification of corn, bean, cotton and soybean using enzymes and heat-resistant proteins

    Directory of Open Access Journals (Sweden)

    Mariney de Menezes

    2008-01-01

    Full Text Available Nesta pesquisa foram avaliados o polimorfismo e a estabilidade de isoenzimas e de proteínas resistentes ao calor em sementes de cultivares de milho, feijão, algodão e soja, com diferentes níveis de qualidade fisiológica. As isoenzimas ,álcool desidrogenase, catalase, esterase e superóxido dismutase analisadas conjuntamente, foram eficientes na separação de oito cultivares de milho. Para as cultivares de feijão, pela enzima peroxidase foi possível diferenciar a cultivar Carioca, no entanto, este padrão mostrou-se variável em sementes com baixa germinação. Não foi possível diferenciar as cultivares de algodão pelas enzimas esterase, superóxido dismutase, diaforase e malato desidrogenase. A cultivar Conquista, de soja, foi diferenciada pelos sistemas enzimáticos esterase e superóxido dismutase e a 'BRS-154' pela esterase. Proteínas resistentes ao calor são polimórficas e estáveis para a identificação de cultivares de milho.In this study the polymorphism and stability of isoenzymes and heat-resistant proteins in corn, bean, cotton, and soybean seeds with different levels of physiological quality were evaluated. The alcohol dehydrogenase, catalase, esterase and superoxide dismutase enzymes and simultaneous analysis were effective in identifying eight corn cultivars. It was observed for the bean cultivars that the peroxidase enzyme allowed differentiation of the Carioca bean cultivar from the others but, the peroxidase enzyme pattern varied in seeds with low-germination percentage. The varieties of cotton could not be differentiated by esterase enzyme, superoxide dismutase, diaphorase and malate dehydrogenase. The Conquista soybean cultivar was separated by superoxide dismutase and esterase enzyme systems and BRS-154 was separated by esterase. Heat-resistant protein patterns showed polymorphism and were stable for corn cultivar identification.

  9. Pengaruh Fraksi Al2o3-Y2o3/Sio2dan Feed Rate Serbuk Terhadap Kekuatan Lekat Danketahanan Termal Lapisan Pada Substrat Hastelloy Dengan Metode Flame Spray Untuk Aplikasi Nosel Roket

    Directory of Open Access Journals (Sweden)

    Abdul Gafur

    2014-03-01

    Full Text Available Nosel roket merupakan bagian roket yang mengatur laju, masa, arah dan tekanan fluida yang keluar dari ruang bakar. Nosel harus dapat menahan energi kinetik dan panas dari  fluida yang berasal dari ruang bakar.Material yang digunakan pada penelitian ini adalah serbuk Al2O3-Y2O3/SiO2 yang memiliki nilai konduktifitas panas rendah. Material tersebut dilapiskan kepada substrat hastelloy® x menggunakan metode flame spray dengan memvariasikan feed rate 6, 12 dan 18 gram/menit. Dengan memvariasikan jumlah komposisi ittria 3, 5 dan 7 % pada Al2O3-Y2O3/SiO2. Lalu dilakukan torch termal pada temperatur 1400 oC dengan waktu maksimal 30 detik agar dapat dilihat ketahanan termal. Dilakukan pengujian termo gravimetrik (TGA untuk mengalisa  kestabilan material pelapis setelah pemanasan dan dilakukan termal ekspos untuk mengetahui perubahan struktur mikro pada lapisan setelah diberi pembebanan termal secara kontinyu. Untuk  menunjang penelitian ini dilakukan beberapa pengujian yang meliputi pengujian SEM, pengujian XRD, dan pengujian Pull off.Hasil penelitian menunjukkan bahwa pada semua   spesimen yang paling stabil pada temperatur tinggi terjadi pada komposisi 80%Al2O3, 13%SiO2, 7%Y2O3 dan feed rate 18 gram/menit. Nilai kekuatan lekat yang paling optimal adalah 8 MPa didapatkan pada komposisi 80%Al2O3, 13%SiO2, 7%Y2O3 dan feed rate 6 gram/menit. Fasa yang stabil pada saat sebelum dan setelah pemanasan adalah kyanite dan ?-Al2O3 .

  10. Effects of heat treatment processes on microstructure and creep properties of a high nitrogen 15Cr-15Ni austenitic heat resistant stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Vu The, E-mail: vutheha@kist.re.kr [Nano-Material Science and Engineering Faculty, University of Science and Technology, 113-Gwahangno, Yuseong-gu, Daejeon (Korea, Republic of); Materials Research Division, Korea Institute of Science and Technology, 39-1 Halwolgok-dong, Wolsong-gil 5, Seoungbuk-gu, Seoul,136-791 (Korea, Republic of); Jung, Woo Sang [Materials Research Division, Korea Institute of Science and Technology, 39-1 Halwolgok-dong, Wolsong-gil 5, Seoungbuk-gu, Seoul,136-791 (Korea, Republic of)

    2011-09-15

    Highlights: {yields} CTMT induced elongated clusters of fine (Nb,Cr,Fe)(C,N) particles. {yields} Hot rolling in MTMT induced evenly distributed fine (Nb,Cr,Fe)(C,N). {yields} Number and distribution of Cu precipitates not affected by hot rolling. {yields} Distribution homogeneity of fine (Nb,Cr,Fe)(C,N) promotes creep strength increase. {yields} Finer grain size structure promotes lower creep ductility. - Abstract: Conventional thermo-mechanical treatment (CTMT) and modified thermo-mechanical treatment (MTMT) process were applied for manufacturing a high nitrogen niobium-stabilized 15Cr-15Ni austenitic alloy. CTMT process consists of 5 h of solution treatment at 1270 deg. C followed by water quenching and subsequent aging at 820 deg. C for 50 h. MTMT process differs from CTMT process in hot plastic deformation performed immediately after the solution treatment at 1270 deg. C and longer aging time. Microstructure and creep properties of the steel obtained by both processing routes were investigated. Creep rupture tests at 750 deg. C showed double increase in rupture time brought about by MTMT process. Examination of crept microstructure by transmission electron microscopy revealed that the improved creep properties in MTMT process were mainly due to improved distribution uniformity of fine nano-sized carbonitride precipitates in the austenitic matrix and that MTMT process has no effects on the number density and distribution of copper precipitates present in the steel. However, the creep ductility in MTMT process drastically reduced comparing to CTMT process. The higher density of grain boundaries due to finer grain recrystallized microstructures and the formation of higher volume fraction of coarser M{sub 23}C{sub 6} precipitates at the boundaries are believed to be the main reason for the lower creep ductility in MTMT process.

  11. Effects of heat treatment processes on microstructure and creep properties of a high nitrogen 15Cr-15Ni austenitic heat resistant stainless steel

    International Nuclear Information System (INIS)

    Highlights: ? CTMT induced elongated clusters of fine (Nb,Cr,Fe)(C,N) particles. ? Hot rolling in MTMT induced evenly distributed fine (Nb,Cr,Fe)(C,N). ? Number and distribution of Cu precipitates not affected by hot rolling. ? Distribution homogeneity of fine (Nb,Cr,Fe)(C,N) promotes creep strength increase. ? Finer grain size structure promotes lower creep ductility. - Abstract: Conventional thermo-mechanical treatment (CTMT) and modified thermo-mechanical treatment (MTMT) process were applied for manufacturing a high nitrogen niobium-stabilized 15Cr-15Ni austenitic alloy. CTMT process consists of 5 h of solution treatment at 1270 deg. C followed by water quenching and subsequent aging at 820 deg. C for 50 h. MTMT process differs from CTMT process in hot plastic deformation performed immediately after the solution treatment at 1270 deg. C and longer aging time. Microstructure and creep properties of the steel obtained by both processing routes were investigated. Creep rupture tests at 750 deg. C showed double increase in rupture time brought about by MTMT process. Examination of crept microstructure by transmission electron microscopy revealed that the improved creep properties in MTMT process were mainly due to improved distribution uniformity of fine nano-sized carbonitride precipitates in the austenitic matrix and that MTMT process has no effects on the number density and distribution of copper precipitates present in the steel. However, the creep ducti steel. However, the creep ductility in MTMT process drastically reduced comparing to CTMT process. The higher density of grain boundaries due to finer grain recrystallized microstructures and the formation of higher volume fraction of coarser M23C6 precipitates at the boundaries are believed to be the main reason for the lower creep ductility in MTMT process.

  12. A study on compatibility of iron-based alloy in liquid metal

    International Nuclear Information System (INIS)

    A study is made on the basic mechanism of the development of the compatibility of liquid-metallic structural material on the assumption that liquid metal acts as high-temperature heat transfer medium. A non-isothermal sodium loop made of 316 stainless steel is used to study the process of corrosion and mass transfer in heat-resistant steel and alloys at the highest temperature region (600-700degC) of flowing sodium containing 1-2 ppm oxygen. Samples used are austenitic stainless steel, precipitation-hardened Ni alloy, and high-Cr ferrite steel. Observations are made of the behaviors of their major components, Fe, Ni, Cr and Mo. Results show that austenitic steel and Ni alloy suffer from selective elution of Ni and Cr and a high rate of corrosion soon after being immersed in sodium. The corrosion rate then gradually decreases until it reaches a constant which depends on the original composition of the sample. This tendency is seen in all other samples except ferrite steel. An equation for the downstream effect is derived, and the corrosion rate at the zero downstream position is determined for each sample. Results suggest that the corrosion rate increases with the Ni and Cr contents in the original samples. It is concluded that the downstream effect results from a decrease in the corrosion rate caused by corrosion products eluted upstream and adsorbed on the surface of the specimen downstream. (N.K.)

  13. Niobium--tantalum alloys alloyed with platinum

    International Nuclear Information System (INIS)

    It was shown that the addition of small quantities of platinum to niobium--tantalum alloys increases their corrosion resistance under strongly aggressive conditions. In 75 percent sulfuric acid at 1500C, the corrosion rate of the niobium alloy containing 30 percent tantalum and 0.2 percent platinum is 4--6 times less than the corrosion rate of this alloy without addition of platinum. It was found that the corrosion rate of the niobium alloy containing 30 percent tantalum and 0.2 percent platinum in 75 percent sulfuric acid solution at 1500C does not depend on the value of the applied potential and is only 0.1 g/m2 h while the corrosion rate of the alloy without platinum increases at potentials which are more positive than +1.7 v

  14. Characterization of Alloys with Potential for Application in Cable-in-Conduit Conductors for High-Field Superconducting Magnets

    Science.gov (United States)

    Walsh, R. P.; Miller, J. R.; Toplosky, V. J.

    2004-06-01

    Since the introduction of the cable-in-conduit conductor (CICC) concept, a variety of alloys have been proposed for fabricating the jacket. The jacket provides primary containment of the supercritical helium coolant and is typically also the primary structural component for the magnet. These functions create requirements for strength, toughness, weldability, and fabricability in tubular form. When the CICC uses Nb3Sn, there are additional requirements to accommodate the manufacturing and heat-treatment processes for the superconductor as well as its strain-sensitive performance during operation. Both of the present favorite jacket alloys, Incoloy 908 and modified (ultra-low carbon) 316LN, have both demonstrated acceptable functionality as well as a few undesirable features. In this paper, we present data from cryogenic mechanical tests on a group of heat-resistant, high-strength superalloys that appear to offer equal or better mechanical performance (e.g. strength, toughness, and modulus) while mitigating the undesirable aspects (e.g. SAGBO in the case of I908 and thermal-expansion mismatch with Nb3Sn in the case of 316LN). Data are presented for each alloy in the as-received and aged conditions. These alloys are presently being considered as candidates for use in the next-generation hybrid magnet for the NHMFL but may also be of interest to the fusion and energy storage communities.

  15. Effect of Cu addition on microstructure and properties of Mg-10Zn-5Al-0.1Sb high zinc magnesium alloy

    Directory of Open Access Journals (Sweden)

    You Zhiyong

    2012-02-01

    Full Text Available To improve the strength, hardness and heat resistance of Mg-Zn based alloys, the effects of Cu addition on the as-cast microstructure and mechanical properties of Mg-10Zn-5Al-0.1Sb high zinc magnesium alloy were investigated by means of Brinell hardness measurement, scanning electron microscopy (SEM, energy dispersive spectroscopy (EDS, XRD and tensile tests at room and elevated temperatures. The results show that the microstructure of as-cast Mg-10Zn-5Al-0.1Sb alloy is composed of ?-Mg, t-Mg32(Al, Zn49, ?-Al2Mg5Zn2 and Mg3Sb2 phases. The morphologies of these phases in the Cu-containing alloys change from semi-continuous long strip to black herringbone as well as particle-like shapes with increasing Cu content. When the addition of Cu is over 1.0wt.%, the formation of a new thermally-stable Mg2Cu phase can be observed. The Brinell hardness, room temperature and elevated temperature strengths firstly increase and then decrease as the Cu content increases. Among the Cu-containing alloys, the alloy with the addition of 2.0wt.% Cu exhibits the optimum mechanical properties. Its hardness and strengths at room and elevated temperatures are 79.35 HB, 190 MPa and 160 MPa, which are increased by 9.65%, 21.1% and 14.3%, respectively compared with those of the Cu-free one. After T6 heat treatment, the strengths at room and elevated temperatures are improved by 20% and 10%, respectively compared with those of the as-cast alloy. This research results provide a new way for strengthening of magnesium alloys at room and elevated temperatures, and a method of producing thermally-stable Mg-10Zn-5Al based high zinc magnesium alloys.

  16. Creep Resistant Zinc Alloy

    Energy Technology Data Exchange (ETDEWEB)

    Frank E. Goodwin

    2002-12-31

    This report covers the development of Hot Chamber Die Castable Zinc Alloys with High Creep Strengths. This project commenced in 2000, with the primary objective of developing a hot chamber zinc die-casting alloy, capable of satisfactory service at 140 C. The core objectives of the development program were to: (1) fill in missing alloy data areas and develop a more complete empirical model of the influence of alloy composition on creep strength and other selected properties, and (2) based on the results from this model, examine promising alloy composition areas, for further development and for meeting the property combination targets, with the view to designing an optimized alloy composition. The target properties identified by ILZRO for an improved creep resistant zinc die-casting alloy were identified as follows: (1) temperature capability of 1470 C; (2) creep stress of 31 MPa (4500 psi); (3) exposure time of 1000 hours; and (4) maximum creep elongation under these conditions of 1%. The project was broadly divided into three tasks: (1) Task 1--General and Modeling, covering Experimental design of a first batch of alloys, alloy preparation and characterization. (2) Task 2--Refinement and Optimization, covering Experimental design of a second batch of alloys. (3) Task 3--Creep Testing and Technology transfer, covering the finalization of testing and the transfer of technology to the Zinc industry should have at least one improved alloy result from this work.

  17. New Methodology to Predict the Long-term Creep Strength of Alloy 617 for a Very High Temperature Reactor

    International Nuclear Information System (INIS)

    Alloy 617 is a prime candidate material for the very high temperature gas-cooed reactor(VHTR) components due to its superior creep resistance above 800 .deg. C when compared to other candidate alloys; Haynes 230, Hastelloy-X and Alloy 800. Considerable creep data for Alloy 617 is available in the literature, and a draft Alloy 617 code case and ASME Boiler and Pressure Vessel (BPV) Code-Section II have also provided allowable stress values for a 105 h design period at temperatures up to 982 .deg. C. However, the creep and oxidation behaviors for Alloy 617 are not well understood yet, and their long-term creep strength should be predicted for use in a design and analysis. So far, Larson-Miller (LM) parameter method known as a time-temperature parameter (TTP) has been the most commonly used to predict the long-term creep life from short-term creep data. TTP constant C in the LM method is unique for a given set of creep rupture data to be analyzed. Temperature dependency of a rupture life, dlogtr /d(1/T), should not change in the data set. But, this assumption is not always valid, because the C for the rupture life changes from a high value of the short term creep to a low value of the long term creep. So, Maruyama et al. have reported that the multi region analysis for Q in Orr-Sherby-Dorn (OSD) parameter could evaluate the long-term rupture of austenite stainless steels and 9-12% Cr steels accurately. However, an overestimation of the long term ruper, an overestimation of the long term rupture in the LM parameter has not been reported for Alloy 617, and furthermore, to avoid it, a multi constant method for the C in the LM parameter has not been demonstrated by others. In this paper, a longer creep life for above 105h at 950 .deg. C was accurately predicted by using a new method with two C values in the LM parameter. Also, oxidation behavior was investigated by using a scanning electron microscope (SEM) and an energy dispersive X-ray spectroscopy (EDX) analysis

  18. Translating VDM to Alloy

    DEFF Research Database (Denmark)

    Lausdahl, Kenneth

    2013-01-01

    The Vienna Development Method is one of the longest established formal methods. Initial software design is often best described using implicit specifications but limited tool support exists to help with the difficult task of validating that such specifications capture their intended meaning. Traditionally, theorem provers are used to prove that specifications are correct but this process is highly dependent on expert users. Alternatively, model finding has proved to be useful for validation of specifications. The Alloy Analyzer is an automated model finder for checking and visualising Alloy specifications. However, to take advantage of the automated analysis of Alloy, the model-oriented VDM specifications must be translated into a constraint-based Alloy specifications. We describe how a subset of VDM can be translated into Alloy and how assertions can be expressed in VDM and checked by the Alloy Analyzer.

  19. Catalyst Alloys Processing

    Science.gov (United States)

    Tan, Xincai

    2014-10-01

    Catalysts are one of the key materials used for diamond formation at high pressures. Several such catalyst products have been developed and applied in China and around the world. The catalyst alloy most widely used in China is Ni70Mn25Co5 developed at Changsha Research Institute of Mining and Metallurgy. In this article, detailed techniques for manufacturing such a typical catalyst alloy will be reviewed. The characteristics of the alloy will be described. Detailed processing of the alloy will be presented, including remelting and casting, hot rolling, annealing, surface treatment, cold rolling, blanking, finishing, packaging, and waste treatment. An example use of the catalyst alloy will also be given. Industrial experience shows that for the catalyst alloy products, a vacuum induction remelt furnace can be used for remelting, a metal mold can be used for casting, hot and cold rolling can be used for forming, and acid pickling can be used for metal surface cleaning.

  20. Nickel base alloy

    International Nuclear Information System (INIS)

    Nickel based alloy mainly containing chromium and molybdenum, for fabricating moulded parts and building up and coating parts, particularly those used in the construction of nuclear reactors. This alloy contains 1.4 to 2.5% carbon, 0 to 2% silicon, 25 to 33% chromium and 6 to 15% molybdenum by weight, the balance, apart from unavoidable impurities, being nickel. The level of activable residual elements, such as cobalt, tungsten and boron in the alloy, is under 0.2%

  1. Superplasticity in titanium alloys

    OpenAIRE

    J. Sieniawski; Motyka, M

    2007-01-01

    Purpose: The paper reports characteristic of superplasticity phenomenon in titanium alloys and possibility of its applications.Design/methodology/approach: The main objective of the paper is to show features of superplastic forming of titanium alloys and current research trends aiming at widespread application of this technology.Findings: In the paper characteristic of selected superplastic titanium alloys was presented. The effect of microstructural parameters on superplasticity was consider...

  2. Low activation ferritic alloys

    Science.gov (United States)

    Gelles, David S. (West Richland, WA); Ghoniem, Nasr M. (Granada Hills, CA); Powell, Roger W. (Pasco, WA)

    1986-01-01

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

  3. The corrosion behavior of high-temperature alloys during exposure for times up to 10,000 h in prototype nuclear process helium at 700 to 900/sup 0/C

    Energy Technology Data Exchange (ETDEWEB)

    Bates, H.G.

    1984-08-01

    A corrosion program is being carried out to establish the long-term corrosion behavior of candidate alloys for the prototype nuclear process (PNP) reactor primary circuit. Results are presented for corrosion tests performed in impure helium over the temperature range of 700 to 900/sup 0/C for times up to 10 000 h. In the helium atmosphere containing 0.5 to 1.5 /sigma phi/bar H/sub 2/O, 15 /sigma phi/bar CO, 20 /sigma phi/bar CH/sub 4/, and 500 /sigma phi/bar H/sub 2/, the three main PNP reference alloys-Inconel617, Nimonic-86, and Hastelloy-X-exhibit excellent corrosion resistance with the carbon uptakes of <0.02% in 10 000 h at temperatures up to 900/sup 0/C. Differences in behavior are related to the composition and morphology of protective surface scales and minor variations in gas impurity levels during test startup. The influence of variations in alloy composition on the long-term stability of these oxide scales is also discussed.

  4. Elaboration of a concept for modelling creep damage and rupture processes in structural components made of heat-resistant CrMoV steels, considering multi-axial stress regimes and formation of pores. Final report

    International Nuclear Information System (INIS)

    The research project was intended to study and elaborate models describing the creep performance of heat-resistant CrMoV steels over the entire creep regime, including the damage processes (tertiary creep). The mathematical description of the creep performance and damages induced is required for the calculation of deformation, stresses and damage affecting structural components over their service life, so that information can be derived about their remanent life. The objective was achieved by describing the interaction between deformation and damage due to cavitation. A model was elaborated that uses an anisotropic cavitation parameter (tensor). The model was tested with and adapted to the material X 20 CrMoV 12 1 and its behaviour at 550 C using data obtained through uni-axial creep tests at constant loading. The modified model was used for recalculation of a long-term experiment at MPA Stuttgart, performed at 550 C with a pipe elbow made of the charge-identical material X 20 XrMoV 12 1, applying the ABAQUS FE program. Mechanical total strains calculated for selected nodes are in good agreement with corresponding measured data. (orig./CB)

  5. Gas-metal reactions of a new Fe-Ni-Cr-W alloy in helium with reactive components and in an H2-CH4-H2S atmosphere in the temperature range 700-9500C

    International Nuclear Information System (INIS)

    A new heat resistant e-Ni-Cr-W alloy (Thermon 4972) was developed within the scope of the prototype nuclear process plant project. This alloy shows mechanical properties and creep rupture properties similar to those of the nickel-based alloy Inconel 617 but, in addition, the new alloy forms protective oxide layers in atmospheres with very low O2 partial pressures. It is shown, by means of some examples, that a variation in the oxide morphology is caused by the modification of the alloy. However, the modifications lead to changes in the carbon activity of the alloy in comparison with the carbon activity of the atmosphere. Both activities must be adjusted to avoid processes such as carburization or decarburization. The results of experiments carried out for durations up to 2000 h at temperatures between 750 and 9500C are compared with those of the alloy Inconel 617. Experiments in sulphidizing and carburizing gas atmospheres were carried out to examine the protective behaviour of the layers built up in H2-CH4-H2S atmospheres with H2O contents between 10% and 10-3%. It is shown that, with an increase in the O2 partial pressure, the layers change from sulphide to oxide. At the same time there is a large variation in the specific mass change. The results are important for the application of the new alloy in plants for coal conversion and are compared with those obtained with the alloy Ipared with those obtained with the alloy Inconel 800 H. (orig.)

  6. Advances in titanium alloys

    International Nuclear Information System (INIS)

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

  7. Topic 2. Zirconium alloys

    International Nuclear Information System (INIS)

    Part 2 of the Proceedings consists of papers on the structure and mechanical properties of zirconium alloys, the effects of alloying elements in the systems Zr-Cu(Cr)-Fe-Mo-V on the absorption of corrosion hydrogen in 300 degC hot water and 400 degC to 500 degC steam, the development of corrosion resistant zirconium alloys for hot water and overheated steam media, the structure of welded joints and fatigue of welded joints of Zr1Nb alloy cans. (J.P.)

  8. Aluminum battery alloys

    Science.gov (United States)

    Thompson, David S. (Richmond, VA); Scott, Darwin H. (Mechanicsville, VA)

    1985-01-01

    Aluminum alloys suitable for use as anode structures in electrochemical cs are disclosed. These alloys include iron levels higher than previously felt possible, due to the presence of controlled amounts of manganese, with possible additions of magnesium and controlled amounts of gallium.

  9. Copper-tantalum alloy

    Science.gov (United States)

    Schmidt, Frederick A. (Ames, IA); Verhoeven, John D. (Ames, IA); Gibson, Edwin D. (Ames, IA)

    1986-07-15

    A tantalum-copper alloy can be made by preparing a consumable electrode consisting of an elongated copper billet containing at least two spaced apart tantalum rods extending longitudinally the length of the billet. The electrode is placed in a dc arc furnace and melted under conditions which co-melt the copper and tantalum to form the alloy.

  10. Thermofluency in zirconium alloys

    International Nuclear Information System (INIS)

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

  11. FRAUD/SABOTAGE Killing Nuclear-Reactors Need Modeling!!!: ``Super'' alloys GENERIC ENDEMIC Wigner's-Disease/.../IN-stability: Ethics? SHMETHICS!!!

    Science.gov (United States)

    O'Grady, Joseph; Bument, Arlden; Siegel, Edward

    2011-03-01

    Carbides solid-state chemistry domination of old/new nuclear-reactors/spent-fuel-casks/refineries/jet/missile/rocket-engines is austenitic/FCC Ni/Fe-based (so miscalled)"super"alloys(182/82;Hastelloy-X,600,304/304L-SSs,...690!!!) GENERIC ENDEMIC EXTANT detrimental(synonyms): Wigner's-disease(WD) [J.Appl.Phys.17,857 (46)]/Ostwald-ripening/spinodal-decomposition/overageing-embrittlement/thermal-leading-to-mechanical(TLTM)-INstability: Mayo[Google: fLeaksCouldKill > ; - Siegel [ J . Mag . Mag . Mtls . 7 , 312 (78) = atflickr . comsearchonGiant - Magnotoresistance [Fert" [PRL(1988)]-"Gruenberg"[PRL(1989)] 2007-Nobel]necessitating NRC inspections on 40+25=65 Westin"KL"ouse PWRs(12/2006)]-Lai [Met.Trans.AIME, 9A,827(78)]-Sabol-Stickler[Phys.Stat.Sol.(70)]-Ashpahani[ Intl.Conf. Hydrogen in Metals, Paris(1977]-Russell [Prog.Mtls.Sci.(1983)]-Pollard [last UCS rept.(9/1995)]-Lofaro [BNL/DOE/NRC Repts.]-Pringle [ Nuclear-Power:From Physics to Politics(1979)]-Hoffman [animatedsoftware.com], what DOE/NRC MISlabels as "butt-welds" "stress-corrosion cracking" endpoint's ROOT-CAUSE ULTIMATE-ORIGIN is WD overageing-embrittlement caused brittle-fracture cracking from early/ongoing AEC/DOE-n"u"tional-la"v"atories sabotage!!!

  12. FRAUD/SABOTAGE Killing Nuclear-Reactors!!! ``Super"alloys GENERIC ENDEMIC Wigner's-Disease IN-stability!!!

    Science.gov (United States)

    Asphahani, Aziz; Siegel, Sidney; Siegel, Edward

    2010-03-01

    Siegel [[J.Mag.Mag.Mtls.7,312(78); PSS(a)11,45(72); Semis.& Insuls.5(79)] (at: ORNL, ANS, Westin``KL"ouse, PSEG, IAEA, ABB) warning of old/new nuclear-reactors/spent-fuel-casks/refineries/ jet/missile/rocket-engines austenitic/FCC Ni/Fe-based (so MIS- called)``super"alloys(182/82;Hastelloy-X; 600;304/304L-SSs; 690 !!!) GENERIC ENDEMIC EXTANT detrimental(synonyms): Wigner's- diseas(WD)[J.Appl.Phys.17,857(46)]; Ostwald-ripening; spinodal- decomposition; overageing-embrittlement; thermomechanical- INstability: Mayo[Google: ``If Leaks Could Kill"; at flickr.com search on ``Giant-Magnotoresistance"; find: [Siegel<<<``Fert"(88) 2007-Nobel/Wolf/Japan-prizes]necessitating NRC inspections on 40+25=65 Westin``KL"ouse PWRs(12/06)]; Lai[Met.Trans.AIME,9A,827 (78)]-Sabol-Stickler[PSS(70)]; Ashpahani[Intl.Conf. H in Metals (77)]; Russell[Prog. Mtls.Sci.(83)]; Pollard[last UCS rept. (9/95)]; Lofaro[BNL/DOE/NRC Repts.]; Pringle[Nuclear-Power:From Physics to Politics(79)]; Hoffman[animatedsoftware.com],...what DOE/NRC MISlabels as ``butt-welds" ``stress-corrosion cracking" endpoint's ROOT-CAUSE ULTIMATE-ORIGIN is WD overageing-embrit- tlement caused brittle-fracture cracking from early/ongoing AEC/DOE-n``u''tional-la``v''atories sabotage!!!

  13. Ultrahigh temperature intermetallic alloys

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-12-01

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

  14. Investigation on mechanical alloying process for vanadium alloys

    International Nuclear Information System (INIS)

    Mechanical alloying (MA) is an efficient approach for fabricating particle-dispersion alloys, and has recently been introduced to strengthen structural materials including vanadium alloys for fusion application. Dissolution behavior of the alloying elements is a key issue for optimizing MA in fabricating particle-dispersion vanadium alloys. This paper studies the MA process for V–4Cr–4Ti alloys with Y addition. The result shows that, in V matrix, the dissolution rate of Y is higher than that of Cr, and the dissolution rate of Cr is higher than that of Ti. In addition, dissolution of milling ball material and dispersion particles can harden the MA-fabricated alloy

  15. Hydrogen embrittlement resistance of nickel alloys with different alloy contents

    Energy Technology Data Exchange (ETDEWEB)

    Sorokina, N.A.; Gal' tsova, V.I.; Rastorgueva, I.A.; Rusinovich, Y.I.; Sergeeva, T.K.; Shumilov, L.G.

    1985-07-01

    Two groups of nickel alloys are investigated to determine the hydrogen embrittlement resistance of the alloys. The first group includes alloys of the Ni-18Cr system, in which the influence of carbon on the properties and the tendency toward hydrogen embrittlement of the solid solution as the basis of the majority of dispersion-hardening nickel alloys was studied. The second group of alloys were treated with elements causing hardening in aging as the result of formation of an intermetallide phase of varying composition. Other alloys contained iron and copper. Copper and aluminum were found to markedly reduce hydrogen impregnation of the copper-containing alloys.

  16. Brazing with plated alloys

    International Nuclear Information System (INIS)

    The use of braze alloy preforms on complex geometry components is at times a very difficult task requiring extensive handling of the parts or even tack welding of the preform to ensure that it is held in place. One method of overcoming these difficulties is the use of plated braze alloys (i.e., filler metals) applied directly to the braze region. Plating helps to avoid the potential for contamination resulting from handling and also ensures that the braze alloy is located properly. Examples are discussed in which an electroplated silver-copper alloy is used as an alternative to the BAg8 preforms and electroless nickel is used as a replacement for an amorphous Ni-P braze alloy foil. A toroidal cooling plate with helical flow channels was fabricated from oxygen-free high conductivity (OFHC) and brazed using the electroplated silver-copper alloy. The silver-copper braze alloy was applied to the copper substrate in a laminated fashion of alternating layers of silver and copper, which in combination approximated the eutectic composition (72% Ag-28% Cu by weight). Examination of the brazed assemblies indicated that in both cases the advantages of using plated braze alloys are numerous. These advantages include decreased labor, improved cleanliness and exactness of braze alloy placement. The primary disadvantage was an increased tendency for solidification defects presumably resulting from contaminants in the plating baths. This last observation is presently being examined i observation is presently being examined in greater detail. The end results is that the assemblies brazed with the plated alloys were acceptable for the intended application and that the use of plating facilitated the successful assembly of these components

  17. Surface alloy structures

    International Nuclear Information System (INIS)

    There have been numerous studies of the surface structure of bulk alloys and their properties when exposed to different environments. To better understand the driving forces in the dynamics of alloy surfaces, there has been greater interest in the growth of alloys from clean surfaces. In some instances, alloys of one atomic layer thickness are formed while in other, a region of 2-4 atomic layers of alloy has been observed. The physical and chemical properties of these surfaces can be significantly different to those of bulk terminated surfaces. In order to understand the importance of the structure on the chemical and physical properties, a series of alloy systems have been investigated to grow alloys controllably layer by layer. This report will concentrate on the growth of alloy surfaces in systems for which there are stable bulk forms. The systems investigated include Ni3Al, Cu3Pd and Al3Pd. Using Low Energy Ion Scattering the surface and near-surface composition was measured while the order was established by Low Energy Electron Diffraction. For Al/Ni(100) a three atomic layer deep alloy surface was formed and the order was the (2x2) structure expected for an ordered bulk termination of Ni3Al(100). The interesting aspect of this surface is that the alloy thickness formed appears to be independent of the availability of Al beyond some initial threshold value. The situation is different for Pd/Cu(100) where the surface was initially disordered. However, once the composition reached that of the bulk like termination a p4g structure was observed. This observation has been explained in terms of size differences between the Cu and Pd atoms. This structure has not been reported for the bulk terminated surface and arises from the growth from a Cu(100) substrate. The critical composition structure involves both the surface and the second layers comprising nearly 50 percent Cu and Pd

  18. Nitrogen pick-up during spray forming of high-alloyed steels and its influence on microstructure and properties of the final products

    International Nuclear Information System (INIS)

    Spray forming is now getting established as a production route for high-alloyed steels. Tool steels for hot work, cold work and high-speed cutting applications and heat resistant steels generally contain high amounts of numerous elements including chromium, vanadium and aluminium, elements with high affinity for nitrogen. Within the spray forming process nitrogen is usually used as protective atmosphere as well as for gas atomization. The investigation considers nitrogen interaction with steel alloys during the spray forming in a closed vessel. Atmospheres with different nitrogen partial pressure are applied during the process. The microstructure of the spray formed, hot worked and finally heat treated steels is compared. Impact strength, wear resistance and strength at elevated temperature are analysed for the tool steels with respect to the nitrogen content. During melting intensive interaction of the melt with the atmosphere occurs according to the solubility of nitrogen in the alloy and high amounts of nitrogen are picked up. As a general result for the conventional alloys under investigation in spray formed condition this leads to reduction of toughness. This can be explained by additional precipitation of nitrides or carbonitrides. Nitrogen pick-up during spray forming can be avoided primarily by remelting in an argon atmosphere

  19. SURFACE MELTING OF ALUMINIUM ALLOYS

    OpenAIRE

    Veit, S.; Albert, D.; Mergen, R.

    1987-01-01

    The wear properties of aluminium base alloys are relatively poor. Laser surface melting and alloying has proved successful in many alloy systems as a means of significantly improving the surface properties. The present work describes experiments designed to establish the scope of laser treatment of aluminium alloys. Aluminium does not absorb CO2 laser light as well as other metals which necessitated first a general study of absorption caotings. Aluminium alloys offer fewer opportunities than ...

  20. UV Curable Heat Resistant Epoxy Acrylate Coatings

    OpenAIRE

    Firdous, Habib; Bajpai, Madhu

    2010-01-01

    ? ?????? ??????? ????????? ?????- ?????????? ??-???????????? ?????????, ???????? ? ???????- ????????? ?? ?????-?????????? ????, ? ??????????? ?????? ?? ???????? ??????????? ????????????????. ???????????, ?????? ???????? ???????????????? ??????? ????????????????? (693 ?) ?? ?????????? ??????? ? ??????? ?????????. ?????????????? ????? ??? ?????????? ?????????? ??????????? ????????, ???????? ?? ?? ???????????, ??? ? ????????????? ????????, ? ???? ????? ??????? ??? ???????...

  1. Heat-resistant hydrophobic-oleophobic coatings

    OpenAIRE

    Uyanik, Mehmet; Arpac, Ertugrul; Schmidt, Helmut K.; AKARSU, Murat; Sayilkan, Funda; Sayilkan, Hikmet

    2006-01-01

    Thermally and chemically durable hydrophobic oleophobic coatings, containing different ceramic particles such as SiO2, SiC, Al 2O3, which can be alternative instead of Teflon, have been developed and applied on the aluminum substrates by spin-coating method. Polyimides, which are high-thermal resistant heteroaromatic polymers, were synthesized, and fluor oligomers were added to these polymers to obtain hydrophobic-oleophobic properties. After coating, Al surface was subjected to Taber-abrasio...

  2. Heat resistant sheathed insulated electrical conductors

    Science.gov (United States)

    Merritt, F. L.; Ducati, A. C.

    1985-02-01

    The leads to a heater for an electrothermal hydrazine monopropellant thruster comprise tungsten conductors wrapped with smaller diameter tungsten support wire and insulated with beads of alumina (Al2O3). A transition section connects the leads to regular leads. An attaching support wire is attached to the heater at one end and to the transition section at the other end. The insulated conductors and attaching wire are wrapped together with nickel ribbon to form a sheath.

  3. Creep equation for heat resistant steels

    Energy Technology Data Exchange (ETDEWEB)

    Kloos, K.H.; Granacher, J. [Technische Hochschule Darmstadt (Germany). Inst. fuer Werkstoffkunde; Monsees, M. [ABB Kraftwerke AG, Baden (Switzerland)

    1998-10-01

    Creep equations are necessary for the design and supervision of high temperature components. To obtain a sound basis for the development of such equations, the typical results of creep rupture tests have usually to be expanded by supplementary tests. At first a creep equation is developed for an extensively tested individual material. This equation then serves as prime solution for the corresponding steel type. The creep equation of the steel type is derived from condensed creep data which are the result of a scatter band analysis of multi-heat creep data. In the analysis, a large number of values of stress to specific strain are assessed on the basis of a time temperature parameter. The result is a family of correlated curves of stress to specific creep strain against time for all temperatures, stresses and strain values covered by the original test results. From these isostrain curves, mean creep curves are derived to form the basis for the modelling of the creep equation. For the development of this equation, a formulation is recommended which contains terms for initial plastic strain and primary, secondary and tertiary creep strain. The individual terms of this equation, which generally depend on stress and temperature, are determined in a stepwise procedure. The methods how such creep equations are developed and how their limits are fixed, are demonstrated for the examples of individual steels of type 14 MoV 6 3 and X 3 CrNiMoN 17 13 and of steel type 1% CrMoNiV according to SEW 555. (orig.) 12 refs.

  4. Heat resistance of methanation nickel catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Araki, M.; Suzuki, K.; Ogawa, K.; Hosoya, T.; Takaya, H.; Takami, Y.; Todo, N.

    1980-03-01

    The thermal stability was tested of seven supported nickel catalysts prepared by different methods, four on alumina support, two on magnesia, and one on magnesium aluminate spinel. The catalyst were exposed to 14% carbon monoxide, 47% hydrogen, and 39% methane at 300/sup 0/, 450/sup 0/, 500/sup 0/, and 650/sup 0/C and 80 kg/sq cm for 1-11 days and the crystallite size measured by X-ray diffraction and electron microscopy. At the highest temperature tested, equilibrium amounts of methane were still produced after ten days. At the lower temperatures, the Ni/Mg/Al and one of the Ni/Al catalysts showed the highest activity, and the Ni/Mg catalysts deactivated most severely in ten-day tests. The deactivation corresponded to crystallite growth. Carbon deposits were small except on the Ni/Mg catalysts, whose deactivation was probably mainly due to the formation of carbon, nickel carbide, or graphite.

  5. Analysis of niobium alloys.

    Science.gov (United States)

    Ferraro, T A

    1968-09-01

    An ion-exchange method was applied to the analysis of synthetic mixtures representing various niobium-base alloys. The alloying elements which were separated and determined include vanadium, zirconium, hafnium, titanium, molybdenum, tungsten and tantalum. Mixtures containing zirconium or hafnium, tungsten, tantalum and niobium were separated by means of a single short column. Coupled columns were employed for the resolution of mixtures containing vanadium, zirconium or titanium, molybdenum, tungsten and niobium. The separation procedures and the methods employed for the determination of the alloying elements in their separate fractions are described. PMID:18960385

  6. Positrons in amorphous alloys

    International Nuclear Information System (INIS)

    Positron annihilation techniques give interesting informations about ''empty spaces'' in amorphous alloys. The results of an extensive research work on the properties of either pre-existing or irradiation induced ''empty spaces'' in four amorphous alloys are presented. The pre-existing empty spaces appear to be small vacancy-like defects. The irradiation induced defects are ''close pairs'' with widely distributed configurations. There is a strong interaction between vacancy like and interstitial like components. A model is proposed, which explains the radiation resistance mechanism of the amorphous alloys. An extensive joint research work to study four amorphous alloys, Fe80B20,Fe40Ni40P14B6, Cu50Ti50, Pd80Si20, is summarized

  7. Brazing dissimilar aluminum alloys

    Science.gov (United States)

    Dalalian, H.

    1979-01-01

    Dip-brazing process joins aluminum castings to aluminum sheet made from different aluminum alloy. Process includes careful cleaning, surface preparation, and temperature control. It causes minimum distortion of parts.

  8. Magnesium Granulated Alloys Processing

    International Science & Technology Center (ISTC)

    Development of a Principle New Basic Technology for Magnesium Granulated Alloys Processing by the Method of Extrusion in Semi-Liquid (semi-Solid) Condition in Order to Obtain Long Shaped Blanks, Round Billets, and Bars of Near Net Shape

  9. Machining of titanium alloys

    CERN Document Server

    2014-01-01

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

  10. Electroplating technologies of alloys

    International Nuclear Information System (INIS)

    In localization of electrosleeving technique, there are some problems like the following articles. Firstly, Patents published by OHT have claimed Ni-P, Ni-B alloy plating and Mo, Mn Cr, W, Co as a pinning agent. Secondly, alloy platings have many restrictions. There are some method to get alloy plating in spite of the various restrictions. If current density increase above limiting current density in one of the metals, both of the metals discharge at the same time. The addition of surface active agent(sufactant) in the plating solution is one of the methods to get alloy plating. Alloy plating using pulse current easily controls chemical composition and structure of deposit. Ni-Fe alloy plating is known to exhibit anomalous type of plating behavior in which deposition of the less noble metal is favoured. Presence of hypophohphite ion can control the iron codeposition by changing the deposition mechanism. Hypophohphite suppresses the deposition of Fe and also promotes Ni. Composite plating will be considered to improve the strength at the high temperature. Addition of particle size of 10?400?m makes residual stress compressive in plate layer and suppress the grain growth rate at the high temperature. Addition of particle makes suface roughness high and fracture stress low at high temperature. But, selection of the kinds of particle and control of additives amount overcome the problems above

  11. Disk Alloy Development

    Science.gov (United States)

    Gabb, Tim; Gayda, John; Telesman, Jack

    2001-01-01

    The advanced powder metallurgy disk alloy ME3 was designed using statistical screening and optimization of composition and processing variables in the NASA HSR/EPM disk program to have extended durability at 1150 to 1250 "Fin large disks. Scaled-up disks of this alloy were produced at the conclusion of this program to demonstrate these properties in realistic disk shapes. The objective of the UEET disk program was to assess the mechanical properties of these ME3 disks as functions of temperature, in order to estimate the maximum temperature capabilities of this advanced alloy. Scaled-up disks processed in the HSR/EPM Compressor / Turbine Disk program were sectioned, machined into specimens, and tested in tensile, creep, fatigue, and fatigue crack growth tests by NASA Glenn Research Center, in cooperation with General Electric Engine Company and Pratt & Whitney Aircraft Engines. Additional sub-scale disks and blanks were processed and tested to explore the effects of several processing variations on mechanical properties. Scaled-up disks of an advanced regional disk alloy, Alloy 10, were used to evaluate dual microstructure heat treatments. This allowed demonstration of an improved balance of properties in disks with higher strength and fatigue resistance in the bores and higher creep and dwell fatigue crack growth resistance in the rims. Results indicate the baseline ME3 alloy and process has 1300 to 1350 O F temperature capabilities, dependent on detailed disk and engine design property requirements. Chemistry and process enhancements show promise for further increasing temperature capabilities.

  12. Aluminum fin-stock alloys

    International Nuclear Information System (INIS)

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

  13. Texture in low-alloyed uranium alloys

    International Nuclear Information System (INIS)

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

  14. Sintered mechanically alloyed iron base alloys

    International Nuclear Information System (INIS)

    A method of producing products from mechanically alloyed, dispersion strengthened iron-base powder comprises consolidating the powder and working the consolidated body to the desired product shape. To obtain a desired grain size in the product, the process includes at least two stages of recrystallisation annealing which may be effected after consolidation or alternatively at least one of the recrystallisation anneals may be carried out while the material is still in powder form. (author)

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

    OpenAIRE

    Blenkinsop, P.

    1993-01-01

    The last few years have been a period of consolidation of existing alloys and processes. While the aerospace industry remains the principal driving force for alloy development, the paper illustrates examples of new markets being established in "older" alloys, by a combination of product/process development and a re-examination of engineering design parameters. Considerable attention is still being directed towards the titanium aluminide systems, but other more conventional alloy developments ...

  16. INVESTIGATION OF MAGNESIUM ALLOYS MACHINABILITY

    Directory of Open Access Journals (Sweden)

    Berat Bar?s BULDUM

    2013-01-01

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

  17. Quenching Alloys in Containerless Processing

    Science.gov (United States)

    Oran, W. A.

    1984-01-01

    Magnetic levitation and gas quenching combined in proposed method to melt and rapidly solidify alloys without contacting container walls. Method used to develop new carbides for drill bits, high-ductility structured steel and new high-strength superplastic alloys.

  18. Structural thermodynamics of alloys

    CERN Document Server

    Manenc, Jack

    1973-01-01

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

  19. De-alloyed platinum nanoparticles

    Science.gov (United States)

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

    2011-08-09

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

  20. FRAUD/SABOTAGE Killing Nuclear-Reactors Need Modeling!!!: "Super"alloys GENERIC ENDEMIC Wigner's-Disease/.../IN-stability: Ethics? SHMETHICS!!!

    Science.gov (United States)

    Asphahani, Aziz; Siegel, Sidney; Siegel, Edward

    2010-03-01

    Carbides solid-state chemistry domination of old/new nuclear- reactors/spent-fuel-casks/refineries/jet/missile/rocket-engines in austenitic/FCC Ni/Fe-based(so miscalled)``super"alloys(182/82; Hastelloy-X,600,304/304L-SSs,...,690!!!) GENERIC ENDEMIC EXTANT detrimental(synonyms): Wigner's-diseas(WD)[J.Appl.Phys.17,857 (1946)]/Ostwald-ripening/spinodal-decomposition/overageing- embrittlement/thermal-leading-to-mechanical(TLTM)-INstability: Mayo[Google:``If Leaks Could Kill"; at flickr.com search on ``Giant-Magnotoresistance"; find: Siegel[J.Mag.Mag.Mtls.7,312 (1978)]<<<``Fert"-"Gruenberg"(1988/89)2007-physics Nobel/Wolf/ Japan-prizes]necessitating NRC-inspections of 40+25 = 65 Westin- ``KLouse PWRs(12/2006)]-Lai[Met.Trans.AIME,9A,827(1978)]-Sabol- Stickler[Phys.Stat.Sol.(1970)]-Ashpahani[Intl.Conf. H in Metals, Paris(1977]-Russell[Prog.Mtls.Sci.(1983)]-Pollard[last UCS rept. (9/1995)]-Lofaro[BNL/DOE/NRC Repts.]-Pringle[Nuclear-Power:From Physics to Politics(1979)]-Hoffman[animatedsoftware.com], what DOE/NRC MISlabels as ``butt-welds" ``stress-corrosion cracking" endpoint's ROOT-CAUSE ULTIMATE-ORIGIN is WD overageing-embritt- lement caused brittle-fracture cracking from early/ongoing AEC/ DOE-n"u"tional-la"v"atories sabotage!!!

  1. Hydrogen in titanium alloys

    International Nuclear Information System (INIS)

    The titanium alloys that offer properties worthy of consideration for fusion reactors are Ti-6Al-4V, Ti-6Al-2Sn-4Zr-2Mo-Si (Ti-6242S) and Ti-5Al-6Sn-2Zr-1Mo-Si (Ti-5621S). The Ti-6242S and Ti-5621S are being considered because of their high creep resistance at elevated temperatures of 5000C. Also, irradiation tests on these alloys have shown irradiation creep properties comparable to 20% cold worked 316 stainless steel. These alloys would be susceptible to slow strain rate embrittlement if sufficient hydrogen concentrations are obtained. Concentrations greater than 250 to 500 wppm hydrogen and temperatures lower than 100 to 1500C are approximate threshold conditions for detrimental effects on tensile properties. Indications are that at the elevated temperature - low hydrogen pressure conditions of the reactors, there would be negligible hydrogen embrittlement

  2. Alloys under irradiation

    Science.gov (United States)

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

    1997-11-01

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

  3. Tungsten Alloy Outgassing Measurements

    CERN Document Server

    Rutherfoord, John P; Shaver, L

    1999-01-01

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

  4. Soldering of aluminium alloys

    International Nuclear Information System (INIS)

    A literature survey about soldering in general and aluminium alloys soldering in particular is presented. The existing methods of soldering aluminium alloys are described. These include soldering with flux, soldering after preliminary plating, vacuum brazipressure and temperature (NTP), sample age calculation based on 14C half life of 5570 and 5730 years, age correction for NTP, dendrochronological corrections and the relative radiocarbon concentration. All results are given with one standard deviation. Input data test (Chauvenet's criterion), gas purity test, standard deviation test and test of the data processor are also included in the program. (author)

  5. Shape memory effect alloys

    International Nuclear Information System (INIS)

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

  6. Surface modification of high temperature iron alloys

    Science.gov (United States)

    Park, Jong-Hee (Clarendon Hills, IL)

    1995-01-01

    A method and article of manufacture of a coated iron based alloy. The method includes providing an iron based alloy substrate, depositing a silicon containing layer on the alloy surface while maintaining the alloy at a temperature of about 700.degree. C.-1200.degree. C. to diffuse silicon into the alloy surface and exposing the alloy surface to an ammonia atmosphere to form a silicon/oxygen/nitrogen containing protective layer on the iron based alloy.

  7. Galvanic corrosion in odontological alloys

    International Nuclear Information System (INIS)

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

  8. Borated aluminum alloy manufacturing technology

    International Nuclear Information System (INIS)

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

  9. Research and application of superplastic forming titanium alloys for commercial aircraft parts

    Energy Technology Data Exchange (ETDEWEB)

    Gershon, B.; Eldror, I. [Israel Aircraft Industries, Ben Gurion International Airport, Lod (Israel)

    2005-07-01

    Titanium alloys sheets have many attractions for the aerospace industry owing to their high strength, low density, heat resistance and other useful properties. Many of the sheet metal structures in airframes have complex shapes and compound curvatures with intricate details. Superplastic forming (SPF), a most recent advancement in titanium sheet forming technology, exploits the excellent characteristic of >1000% elongation potential for the fabrication of complex configurations not achievable by conventional methods. SPF technology can also reduce manufacturing cost by shortening the preparation time, eliminating the need for extensive welding or other joining methods and by reducing the number of manufacturing steps. Consequently, high profit margins may be achieved in serial aircraft production. This paper outlines the research at Israel Aircraft Industries (IAI) of SPF technology and its application in producing complex-shape Ti sheet parts for the new IAI commercial aircrafts, models ''G-150'' and ''G-200''. Examples of both actual and experimental parts are given, together with details of the manufacturing parameters employed. An economical analysis is also included. (orig.)

  10. Quinary metallic glass alloys

    Science.gov (United States)

    Lin, Xianghong (Pasadena, CA); Johnson, William L. (Pasadena, CA)

    1998-01-01

    At least quinary alloys form metallic glass upon cooling below the glass transition temperature at a rate less than 10.sup.3 K/s. Such alloys comprise zirconium and/or hafnium in the range of 45 to 65 atomic percent, titanium and/or niobium in the range of 4 to 7.5 atomic percent, and aluminum and/or zinc in the range of 5 to 15 atomic percent. The balance of the alloy compositions comprise copper, iron, and cobalt and/or nickel. The composition is constrained such that the atomic percentage of iron is less than 10 percent. Further, the ratio of copper to nickel and/or cobalt is in the range of from 1:2 to 2:1. The alloy composition formula is: (Zr,Hf).sub.a (Al,Zn).sub.b (Ti,Nb).sub.c (Cu.sub.x Fe.sub.y (Ni,Co).sub.z).sub.d wherein the constraints upon the formula are: a ranges from 45 to 65 atomic percent, b ranges from 5 to 15 atomic percent, c ranges from 4 to 7.5 atomic percent, d comprises the balance, d.multidot.y is less than 10 atomic percent, and x/z ranges from 0.5 to 2.

  11. Shape Memory Alloy Actuator

    Science.gov (United States)

    Baumbick, Robert J. (Inventor)

    2002-01-01

    The present invention discloses and teaches a unique, remote optically controlled micro actuator particularly suitable for aerospace vehicle applications wherein hot gas, or in the alternative optical energy, is employed as the medium by which shape memory alloy elements are activated. In gas turbine powered aircraft the source of the hot gas may be the turbine engine compressor or turbine sections.

  12. Defects in amorphous alloys

    International Nuclear Information System (INIS)

    The authors investigate several amorphous alloys using positrons. Intrinsic defects with a vacancy-like local structure have been identified. Lifetime and Doppler broadening measurements have been carried out simultaneously on the same specimen. Some specimens were irradiated by electrons and radiation induced defects have been observed. (Auth.)

  13. The in-situ Ti alloying of aluminum alloys and its application in A356 alloys

    Directory of Open Access Journals (Sweden)

    Zongxia LIU

    2005-05-01

    Full Text Available This research has investigated the in-situ Ti alloying of aluminum alloys and its application to A356 alloys and wheels through the evaluation of microstructure and mechanical properties. The results showed that stable titanium content can be obtained by adding a small quantity of TiO2 into electrolyte of pure aluminum. Under this approach, a greater than 95% absorptivity of titanium was achieved, and the microstructure of the specimens was changed to fineequiaxed grains from coarse columnar grains in the pure aluminum. In comparison with the tradition A356 alloys and wheels, the corresponding microstructure in the testing A356 alloys and wheels was finer. Although the tensile strength was similar between the testing and the tradition A356 alloys and wheels, the ductility of the former (testing is superior to that of the later (tradition, leading to an excellent combination of strength and ductility from the testing alloys and wheels.

  14. Structure of dental gallium alloys.

    Science.gov (United States)

    Herø, H; Simensen, C J; Jørgensen, R B

    1996-07-01

    The interest in gallium alloys as a replacement for amalgam has increased in recent years due to the risk of environmental pollution from amalgam. Alloy powders with compositions close to those for alloys of amalgam are mixed with a liquid gallium alloy. The mix is condensed into a prepared cavity in much the same way as for amalgam. The aim of the present work was to study the structure of: (1) two commercial alloy powders containing mainly silver, tin and copper, and (2) the phases formed by mixing these powders with a liquid alloy of gallium, indium and tin. One of the alloy powders contained 9 wt% palladium. Cross-sections of cylindrical specimens made by these gallium mixes were investigated by scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction. Discrete grains of the following phases were found to be present in both gallium alloys: hexagonal Ag2Ga, tetragonal Cu(Pd)Ga2, cubic Ag9In4 and tetragonal beta-Sn. Indications of hexagonal or orthorhombic Ag2Sn were found in the remaining, unreacted alloy particles. In the palladium-containing alloy the X-ray reflections indicate a minor fraction of cubic Cu9Ga4 in addition to the Cu(Pd)Ga2 phase. Particles of beta-Sn are probably precipitated because Sn-Ga phases cannot be formed according to the binary phase diagram. PMID:8805980

  15. Zirconium alloys in nuclear engineering

    International Nuclear Information System (INIS)

    An original approach to alloying zirconium has been developed in the Soviet Union, as distinct from that broadly used abroad in zircalloy, in the development of zirconium alloys for the cladding of fuel elements and channel pipes. Zirconium alloys with 1% and 2.5% Nb, i.e. N-1, and N-2.5 alloys - have been developed and successfully used at APS with RBMK and VVER reactors. Characteristics of niobium as an alloying element are presented, and properties of N-1 and N-2.5 alloys, corrosion-resistant under conditions of boiling, uncorrected regime of RBMK, and also under conditions of VVER, are discussed. Alloys suitable for the fabrication of fuel-element cladding and channel pipes of reactors with nuclear superheating of steam are considered. For the first time, regularities in the effect of composition of alloys on their oxidizability and hydrogenation in superheated steam are presented. Elucidated are results of important investigations of the Soviet scientists into the mechanism of corrosion of zirconium alloys on the basis of diffusion experiments and the determination of the composition of oxide films on alloys containing iron and tin by the nuclear gamma resonance method. On this basis, a systematization of the effect of elements on zirconium corrosion is given

  16. Advanced ordered intermetallic alloy deployment

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-04-01

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

  17. Materials data handbook, aluminum alloy 7075

    Science.gov (United States)

    Sessler, J.; Weiss, V.

    1967-01-01

    Materials data handbook on aluminum alloy 7075 includes data on the properties of the alloy at cryogenic, ambient, and elevated temperatures, and other pertinent engineering information required for the design and fabrication of components and equipment utilizing this alloy.

  18. High-temperature Titanium Alloys

    Directory of Open Access Journals (Sweden)

    A.K. Gogia

    2005-04-01

    Full Text Available The development of high-temperature titanium alloys has contributed significantly to the spectacular progress in thrust-to-weight ratio of the aero gas turbines. This paper presents anoverview on the development of high-temperature titanium alloys used in aero engines and potential futuristic materials based on titanium aluminides and composites. The role of alloychemistry, processing, and microstructure, in determining the mechanical properties of titanium alloys is discussed. While phase equilibria and microstructural stability consideration haverestricted the use of conventional titanium alloys up to about 600 "C, alloys based on TiPl (or,, E,AINb (0, TiAl (y, and titaniumltitanium aluminides-based composites offer a possibility ofquantum jump in the temperature capability of titanium alloys.

  19. Rare earth ferrosilicon alloy

    International Nuclear Information System (INIS)

    In order to obtain RE ferrosilicon alloy with good quality and competitive price, it is essential that proper choice of raw materials, processing technology and equipments should be made based on the characteristics of Bai-Yun-Ebo mineral deposits. Experimental work and actual production practice indicate that pyrometallurgical method is suitable for the extraction and isolation of the rare earths and comprehensive utilization of the metal values contained in the feed material is capable of reducing cost of production of RE ferrosilicon alloy. In the Bai-Yun-Ebo deposit, the fluorite type medium lean ore (with respect to iron content) makes a reserve of considerable size. The average content of the chief constituents are given

  20. Shape Memory Alloys

    Science.gov (United States)

    This experiment, presented by the National Nanotechnology Infrastructure Network, covers Shape Memory Alloys or Smart Materials. A Smart Material or Shape Memory Alloys belongs to a class of materials which displays the shape memory effect (SME); they possess the ability to radically change crystal structure or phase at a distinct temperature. The lab will "explore how smart materials work and what applications these materials are used in." Additionally, students will be provided with a brief history lesson about the origins of smart material. The experiment is quite fun, students will observe how smart materials can "think and do amazing things." A student and teacher guide is provided with the lab. Overall, this is a great exercise for any science classroom interested in the workings of nanotechnology.

  1. Multicomponent and High Entropy Alloys

    Directory of Open Access Journals (Sweden)

    Brian Cantor

    2014-08-01

    Full Text Available This paper describes some underlying principles of multicomponent and high entropy alloys, and gives some examples of these materials. Different types of multicomponent alloy and different methods of accessing multicomponent phase space are discussed. The alloys were manufactured by conventional and high speed solidification techniques, and their macroscopic, microscopic and nanoscale structures were studied by optical, X-ray and electron microscope methods. They exhibit a variety of amorphous, quasicrystalline, dendritic and eutectic structures.

  2. THERMAL STABILITY OF AMORPHOUS ALLOYS

    OpenAIRE

    Buschow, K.

    1980-01-01

    The crystallization of the amorphous alloys Zr-Rh, Zr-Fe, Dy-Co and Gd-Co was studied by means of differential scanning calorimetry and X-ray diffraction. In several of these alloys we determined the apparent activation energy for diffusion by means of the Kissinger method. There appears to be no simple relationship between the crystallization temperatures and these apparent activation energies. The present results together with data available on many other amorphous alloys between two metals...

  3. Alloy catalyst material

    DEFF Research Database (Denmark)

    Stephens, Ifan Technical University of Denmark,

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

  4. Shape memory alloy actuator

    Science.gov (United States)

    Varma, Venugopal K. (Knoxville, TN)

    2001-01-01

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

  5. Analysis of laser alloyed surfaces

    International Nuclear Information System (INIS)

    Surface alloys of precious metals have many advantages over bulk alloys, the most obvious of which is cost reduction due to the reduced consumption of precious metal. There are several techniques for producing surface alloys. In this paper the laser irradiation technique is presented. The following lasers: CW CO2, Q-switched Nd-YAG, frequency double Q-switched Nd-YAG, and pulsed ruby were used to irradiate and melt thin solid films of precious metals on metal substrates. This causes the surfaces to melt to a depth of approximately 10,000A. Alloying then takes place in the liquid phase where most metals are miscible. The high quench rates obtainable by this method of melting can result in the forming of metastable alloys. This melting and regrowth process is well understood and has been discussed in the literature over the last few years. This paper deals with two binary alloy systems, Au-Ni and Pd-Ti. Surface alloys of Au-Ni with a wide range of concentrations have been produced by laser irradiation of thin Au films on Ni. These films have been analyzed using Rutherford backscattering (RBS) and channeling. Many thin film metals other than Au have also been successfully alloyed using these methods. An example of a potential application is the laser surface alloying of Pd to Ti for corrosion passivation

  6. Low activation ferritic alloys

    International Nuclear Information System (INIS)

    This patent describes a ferritic alloy having a banitic or martensitic microstructure when heated treated and tempered and characterized by low activation properties, the alloy consisting essentially of: chromium-2.0 to 13 percent by weight; vanadium or, tungsten, or tantalum in a total amount of-0.3 to 1.5 percent by weight; carbon-0.75 to 0.30 percent by weight; manganese-0.01 to 15.0 percent by weight; silicon-0.05 to 1.0 percent by weight; phosphorous-less than 0.01 percent by weight; nitrogen-less than 0.04 percent by weight; sulphur-less than 0.01 percent by weight; copper-less than 0.003 percent by weight; molybdenum-less than 0.12 percent by weight; niobium-less than 0.003 percent by weight; nickel-less than 0.1 percent by weight; the remainder of the alloy being iron

  7. Low alloy tempering steel

    International Nuclear Information System (INIS)

    The invention deals with the use of a low-alloy steel in tempered state to produce articles with good tempering properties having a minimum tensile strength of 700 N/mm2 and an impact strength (DVM sample) of at least 55 joule. A steel with 0.35 to 0.6% C, 0.1 to 0.5% Si, 0.3 to 1.0% Mn, 0.1 to 0.6% Cr, 0.01 to 0.1% Nb, rest iron is suggested for the purpose which after austeniting by fast cooling and subsequent annealing is quenched and tempered. The invention is based on the fact that an addition of niobium combined with the choice of the suitable austeniting temperature, which on the one hand allows the solution of a sufficient amount of niobium but should however prevent the occurence of coarse grain, leads to strength and toughness properties which have only been achieved from higher-alloys tempering steels. According to a preferential design of the invention, a further steel is proposed which besides the above mentioned additions contains 0.08 to 0.12% V. The strength values of this steel are compared in figures with those of the higher-alloy and thus more expensive steel 30CrNiMo8. (GSC)

  8. Aluminum alloy impact sparkling

    Directory of Open Access Journals (Sweden)

    M. Dudyk

    2008-08-01

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

  9. Laser surface alloying of aluminium-transition metal alloys

    Directory of Open Access Journals (Sweden)

    Almeida, A.

    1998-04-01

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

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

  10. Forming of fine-grained superplastic structures of two types of precipitation in austenite alloys on Ni-Cr and Co-Ni basis

    International Nuclear Information System (INIS)

    Full text: Authors of the submitted work carry out research of influence of a high degree of cold rolling deformation on structural-phase transformations at the subsequent ageing industrial dispersion-hardening alloys on Ni-Cr and Mo-Ni basis. By optical metallography and transmission electronic microscopy methods the parameters the dislocations' structure forming by different degrees of deformation and structure formed during precipitation from a solid solution at ageing of were established. The data of researches of thin structure are compared to the data on mechanical properties of a material. Using features of preliminary cold deformation at ageing alloys, it is possible to offer phase and structural transformations easily sold ways of reception of a ultra fine-grained microstructure in alloys 36NKhTYu, 40KhNYu, 67KN5B that will allow to realize in the given alloys transition in a superplastic condition. In this connection acknowledgement of superplastic properties of the given alloys with the various mechanical and thermal processing (MTP) is actual. MTP of alloys 36NKhTYu, 40KhNYu, 67KN5B (industrial dispersion-hardening heat resisting alloys of standard structure) included training on a single-phase solid solution, flattering and ageing in vacuum is no worse 1 Pa. Research of thin structure was carried out on transmission electronic microscope JEM-100 CX (foil). For studying the common character of structure used an optical microscope 'Neophot 21', and diffractical microscope 'Neophot 21', and diffractometer DRON -3 for studying phase structure of samples. High-temperature test of samples of an alloys 40KhNYu and 67KN5B on a stretching carried out on installation 1246P-2/2500 in an interval of temperatures 1153-1323 K in vacuum with residual pressure not worse 10-2 Pa. Mechanical tests included one axis static tension measurement of breaking point ?b, relative fluid limit ?02, relative lengthening till gap ? (%). The fractography a cross break studied on electron-zoned microanalyzer SUPERPROBE 733 JEOL in a raster mode secondary electrons. Result of the analysis of experimental data are the following conclusions: 1. Metallography and electron-microscopic researches it is established, that in an alloy 36NKhTYu to a condition of superplasticity there corresponds a special microstructure from elementary cells of cellular precipitation. The size and volume fraction in an alloy of these cells is determined by time of annealing at the constant temperature. A superplastic condition in an alloy 40KhNYu and 67KH5B at the structure provides a micro duplex. 2. The concrete modes of mechanical-thermal processing including a high degree of deformation and the subsequent ageing are recommended, allowing to receive fine-grained structures with high properties of plasticity in alloys 36NKhTYu, 40KhNYu, 67KN5B. 3. One axis the stretching of samples of an alloy 40KhNYu and 67KN5B at high temperature has shown that preliminary processing, namely: training 1323 K (5 min) + flattering with ?=90 % provides occurrence of a superplastic condition of an alloy in an interval of deformation's speeds 10-4-10-2 s-1 and in an interval of temperatures 1153-1323 K (40KhNYu) and training 1423 K (10 min) + flattering with ?=90 % provides occurrence of a superplastic condition of an alloy in an interval of deformation's speeds 0.8·10-3 s-1 and the temperature 1143 K (67KN5B)

  11. The in-situ Ti alloying of aluminum alloys and its application in A356 alloys

    OpenAIRE

    Zongxia LIU; Mousheng SONG; Tianfu SONG

    2005-01-01

    This research has investigated the in-situ Ti alloying of aluminum alloys and its application to A356 alloys and wheels through the evaluation of microstructure and mechanical properties. The results showed that stable titanium content can be obtained by adding a small quantity of TiO2 into electrolyte of pure aluminum. Under this approach, a greater than 95% absorptivity of titanium was achieved, and the microstructure of the specimens was changed to fineequiaxed grains from coarse columnar ...

  12. Radiation Effects in Refractory Alloys

    International Nuclear Information System (INIS)

    In order to achieve the required low reactor mass per unit electrical power for space reactors, refractory alloys are essential due to their high operating temperature capability that in turn enables high thermal conversion efficiencies. One of the key issues associated with refractory alloys is their performance in a neutron irradiation environment. The available radiation effects data are reviewed for alloys based on Mo, W, Re, Nb and Ta. The largest database is associated with Mo alloys, whereas Re, W and Ta alloys have the least available information. Particular attention is focused on Nb-1Zr, which is a proposed cladding and structural material for the reactor in the Jupiter Icy Moons Orbiter (JIMO) project. All of the refractory alloys exhibit qualitatively similar temperature-dependent behavior. At low temperatures up to ?0.3TM, where TM is the melting temperature, the dominant effect of radiation is to produce pronounced radiation hardening and concomitant loss of ductility. The radiation hardening also causes a dramatic decrease in the fracture toughness of the refractory alloys. These low temperature radiation effects occur at relatively low damage levels of ?0.1 displacement per atom, dpa (?2x1024 n/m2, E>0.1 MeV). As a consequence, operation at low temperatures in the presence of neutron irradiation must be avoided for all refractory alloys. At intermediate temperatures (0.3 to 0.6 TM), void swelling and irradiation creep are the dominant effects of n creep are the dominant effects of irradiation. The amount of volumetric swelling associated with void formation in refractory alloys is generally within engineering design limits (>10 dpa). Very little experimental data exist on irradiation creep of refractory alloys, but data for other body centered cubic alloys suggest that the irradiation creep will produce negligible deformation for near-term space reactor applications

  13. Bismuth-tin-indium alloy

    International Nuclear Information System (INIS)

    A substantially lead free low melting point, sealing alloy of bismuth, tin and indium consists essentially of 53 to 76 weight percent bismuth, 22 to 35 weight percent tin and 2 to 12 weight percent indium, said alloy being substantially resistant to atmospheric oxidation at temperatures up to 1500C

  14. Shape memory alloy thaw sensors

    Science.gov (United States)

    Shahinpoor, Mohsen (Albuquerque, NM); Martinez, David R. (Albuquerque, NM)

    1998-01-01

    A sensor permanently indicates that it has been exposed to temperatures exceeding a critical temperature for a predetermined time period. An element of the sensor made from shape memory alloy changes shape when exposed, even temporarily, to temperatures above the Austenitic temperature of the shape memory alloy. The shape change of the SMA element causes the sensor to change between two readily distinguishable states.

  15. NDT for uranium alloys

    International Nuclear Information System (INIS)

    This paper is divided into the three main areas of application of NDT to uranium and uranium alloys: (1) The determination of properties is done by NDT methods where it is important to measure the properties on the finished product rather than on samples. (2) Detection and qualification of flaws is the main area that most people think of as nondestructive testing. (3) Since uranium is subject to corrosion, we have to protect it with coatings, and we need to evaluate those coatings. 15 figures

  16. Alternate piping alloy qualification

    International Nuclear Information System (INIS)

    Intergranular stress corrosion cracking (IGSCC) of welded stainless steel piping in Boiling Water Reactors (BWRs), and more recently in Pressurized Water Reactors (PWRs), has been a problem of concern to the power generation industry. An effort to qualify alternate materials was instituted by General Electric and sponsored in part by the Electric Power Research Institute (EPRI) under joint GE/EPRI contract RP968-1. The EPRI-sponsored effort is a four-year program designed to qualify and implement into BWR service an alternate piping alloy that is not subject to intergranular stress corrosion cracking within the plant design lifetime. The program is described

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

    International Nuclear Information System (INIS)

    A study was initiated which included nineteen aluminum alloys. Tests were conducted in high purity water at 3600C and flow tests (approx. 20 ft/sec) in reactor process water at 1300C (TF-18 loop tests). High-silicon alloys and AlSi failed completely in the 3600C tests. However, coupling of AlSi to 8001 aluminum suppressed the failure. The alloy compositions containing iron and nickel survived tht 3600C autoclave exposures. Corrosion rates varied widely as a function of alloy composition, but in directions which were predictable from previous high-temperature autoclave experience. In the TF-18 loop flow tests, corrosion penetrations were similar on all of the alloys and on high-purity aluminum after 105 days. However, certain alloys established relatively low linear corrosion rates: Al-0.9 Ni-0.5 Fe-0.1 Zr, Al-1.0 Ni-0.15 Fe-11.5 Si-0.8 Mg, Al-1.2 Ni-1.8 Fe, and Al-7.0 Ni-4.8 Fe. Electrical polarity measurements between AlSi and 8001 alloys in reactor process water at temperatures up to 1500C indicated that AlSi was anodic to 8001 in the static autoclave system above approx. 500C

  18. Aluminum alloy and associated anode and battery

    International Nuclear Information System (INIS)

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

  19. Stable palladium alloys for diffusion of hydrogen

    Science.gov (United States)

    Patapoff, M.

    1973-01-01

    Literature search on hydrogen absorption effect on palladium alloys revealed existence of alloy compositions in which alpha--beta transition does not take place. Survey conclusions: 40 percent gold alloy of palladium should be used in place of palladium; alloy must be free of interstitial impurities; and metallic surfaces of tube must be clean.

  20. The interaction of CsI with high-chromium alloys in the presence of oxygen

    International Nuclear Information System (INIS)

    Mixtures of CsI with 304 stainless steel, Incoloy 800 and Hastelloy X turnings as well as with Fe, Ni and Cr powders were heated either in air, oxygen or helium for periods of several hours at temperatures of 550 to 6500C. The reaction product was dissolved in water and analysed. The results are reported and discussed. (U.K.)

  1. Properties and use of chromium alloys

    International Nuclear Information System (INIS)

    A description is given of the strength and plastic properties of chromium alloys at various temperatures, as well as the influence of the alloying on these properties. Given are the data, regarding the enhancement of the metal plasticity, using the electric current effect; its technological use alternatives are also suggested. Good properties of the high-alloyed VKh-4 chromium alloy (67%Cr) are noted. The alloy has been worked out, combining the chromium- and nickel-based solid solutions and their additional alloying with tungsten, titanium and vanadium. The alloy is used for the parts, exposed to long-time working at the 600-1400 deg C cyclic heating

  2. Oxidation resistant alloys, method for producing oxidation resistant alloys

    Science.gov (United States)

    Dunning, John S.; Alman, David E.

    2002-11-05

    A method for producing oxidation-resistant austenitic alloys for use at temperatures below 800 C. comprising of: providing an alloy comprising, by weight %: 14-18% chromium, 15-18% nickel, 1-3% manganese, 1-2% molybdenum, 2-4% silicon, 0% aluminum and the balance being iron; heating the alloy to 800 C. for between 175-250 hours prior to use in order to form a continuous silicon oxide film and another oxide film. The method provides a means of producing stainless steels with superior oxidation resistance at temperatures above 700 C. at a low cost

  3. Stainless-Steel-Gadolinium Alloys

    International Nuclear Information System (INIS)

    Because of the excellent corrosion resistance of stainless steels and the interest in gadolinium as a poison material, alloys of the two compounds were studied.Gadolinium was alloyed with AISE 304-type and chromium-type stainless steels; and then phase relationships, fabricability and properties were studied. The melting points of minor phases in alloys containing low percentages of gadolinium were noted to have a large effect on the structures resulting from equilibrating treatments and fabricability of the steels. When gadolinium was alloyed with the chromium-nickel-type steel, two minor phases, Fe9Gd and Ni7Gd, were observed to melt at 1080°C, which limited the heat treatment and fabrication temperatures. Alloys with up to 5 wt.% gadolinium were successfully fabricated, and mechanical and corrosion properties were determined. No changes in the mechanical properties or resistance to hot-water corrosion of the steel were observed on alloying with up to about 3 wt.% gadolinium. Because of fabrication temperature limitations placed on chromium-nickel steels by the melting point of the minor phases, the effects of gadolinium on chromium steels were studied. Only one minor phase that melted at 1320°C was noted on investigation of the 10 wt. % gadolinium isopleth in the chromium-iron-gadolinium alloy system. This property would enable one to equilibrate and fabricate these gadolinium steels at normally used temperatures. (author)emperatures. (author)

  4. Thermoelectric hardening of alloy steels

    International Nuclear Information System (INIS)

    Consideration is given to results of improving surface hardness of alloyed steels by holding during some ? time at some t temperature in oxide melt with transmission of low density current. It is shown that thermoelectric hardening of different low- and high-alloy steels enables to increase microhardness of the surface layer by 40...300%. This is conditioned by layer enrichment with possivating elements, entering steel composition, such as chromium, aluminium, nickel, molybdenum, vanadium. Concentration of alloying components grows 1.5...4.0 times. 5 refs

  5. Iron-nickel-chromium alloys

    International Nuclear Information System (INIS)

    Age hardening iron-nickel-chromium alloy with ?' or ?' and ?'' phases made of nickel 33 to 39.5 %, chromium 7.5 to 16%, niobium 1.5 to 4%, silicon 0.1 to 1% zirconium 0.01 to 0.8%, titanium 1 to 3%, aluminum 0.2 to 0.6% and iron. This alloy is particularly adapted to make pipes for fast breeder reactors and fuel cladding. This alloy shows good mechanical properties at high temperature, good swelling resistance under irradiation and low neutron absorption

  6. Alloying and Casting Furnace for Shape Memory Alloys Project

    National Aeronautics and Space Administration — The concept in the proposed project is to create a melting, alloying and casting furnace for the processing titanium based SMA using cold crucible techniques. The...

  7. New master-alloy for the preparation of zirconium alloys

    International Nuclear Information System (INIS)

    Arc melting process using consumable electrodes for producing zirconium based alloy ingots whereby at least one part of the added elements, tin, iron and/or chromium, is introduced with the substances that will form the consumable electrode as a master-alloy containing: Sn 50 to 85%, Zr 5 to 30%, Fe 0 to 20%, Cr 0 to 20% of which the Fe and Cr level is between 3 and 30%

  8. Hollow Blades from Titanium Alloys

    International Science & Technology Center (ISTC)

    Development of Elements of the Technology Producing Hollow Blades from Submicrocrystalline Titanium Alloys by Combining Molding and Diffusion Welding under Low-Temperature Superplasticity, Including Non-Destructive Quality Control over Parts Produced

  9. Emissivity measurements on aeronautical alloys

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-01-21

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

  10. Aluminum alloy ultrahigh vacuum system

    International Nuclear Information System (INIS)

    A complete aluminum alloy vacuum system for ultrahigh vacuum has been developed for the TRISTAN electron-positron collider. The present system satisfied conditions such as high performance, high reliability, impedance matching, simplicity, low wasted space betweem magnets, small size, light weight, low residual radioactivity, completely nonmagnetic, and low cost. New concepts from the research and development at KEK are as follows: 1. aluminum alloys are low residual radioactivity materials, 2. bakable Al-Conflat flanges with metal seals, 3. close-contact sealing mechanism with super-mirror finished surfaces, 4. extremely low outgassing rate in special extrusion and in special surface treatments, 5. aluminum alloy to ceramics or sapphire seals with vacuum brazing, 6. aluminum alloy materials which are acceptable for localized high density heating. Such an aluminum vacuum system can be widely used in other particle accelerators, nuclear fusion apparatus, semiconductor processes, surface analyzers and various ultrahigh vacuum systems. (author)

  11. Nanocrystalline Alloys with Enhanced Properties

    International Science & Technology Center (ISTC)

    The Creation of Scientific Basis for Development of Technology for Manufacturing Sheets and Strips of Fe- and Cu-based Alloys with Nanocrystalline Structure with Enhanced Strength, Electric Conductivity and Damping Properties

  12. Emissivity measurements on aeronautical alloys

    International Nuclear Information System (INIS)

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

  13. Shape memory alloy thaw sensors

    Science.gov (United States)

    Shahinpoor, M.; Martinez, D.R.

    1998-04-07

    A sensor permanently indicates that it has been exposed to temperatures exceeding a critical temperature for a predetermined time period. An element of the sensor made from shape memory alloy changes shape when exposed, even temporarily, to temperatures above the austenitic temperature of the shape memory alloy. The shape change of the SMA element causes the sensor to change between two readily distinguishable states. 16 figs.

  14. [MRO] Oligocrystalline Shape Memory Alloys

    OpenAIRE

    Chen, Ying; Schuh, Christopher A.; Ueland, Stian Melhus

    2011-01-01

    Copper-based shape memory alloys (SMAs) exhibit excellent shape memory properties in single crystalline form. However, when they are polycrystalline, their shape memory properties are severely compromised by brittle fracture arising from transformation strain incompatibility at grain boundaries and triple junctions. Oligocrystalline shape memory alloys (oSMAs) are microstructurally designed SMA structures in which the total surface area exceeds the total grain boundary area, and triple juncti...

  15. Uranium-Based Cermet Alloys

    International Nuclear Information System (INIS)

    The paper describes certain features of dispersion-hardened uranium-based cermets. As possible hardening materials, consideration was given to UO2, UC, Al2O3, MgO and UBe13. Data were obtained on the behaviour of uranium alloys containing the above-mentioned admixtures during creep tests, short-term strength tests and cyclic thermal treatment. The corrosion resistance o f UBe13-based uranium alloys was also studied. )author)

  16. Castable hot corrosion resistant alloy

    Science.gov (United States)

    Barrett, Charles A. (inventor); Holt, William H. (inventor)

    1988-01-01

    Some 10 wt percent nickel is added to an Fe-base alloy which has a ferrite microstructure to improve the high temperature castability and crack resistance while about 0.2 wt percent zirconium is added for improved high temperatur cyclic oxidation and corrosion resistance. The basic material is a high temperature FeCrAl heater alloy, and the addition provides a material suitable for burner rig nozzles.

  17. TEM microstructure investigations of aluminium alloys used for laser alloying

    Directory of Open Access Journals (Sweden)

    K. Labisz

    2012-12-01

    Full Text Available Purpose: In this paper there are presented results of Transmission Electron Microscope investigation concerning the structure of the AlSi7Cu4 cast aluminium alloy using for alloying and remelting with the high power diode laser (HPDL. There are also presented the results of the thermo-derivative analysis performed using the UMSA (Universal Metallurgical Simulator and Analyser device, allowing to determine the specific points of the solidifying alloy, what is helpful for phase determination occurred in this alloy. In this work especially the changes of the precipitation type, size and shape were determined.Design/methodology/approach: The investigations were performed using electron microscopy for the microstructure and phases determination. By mind of the transmission electron microscopy, especially selected area diffraction method appliance it was possible to determine the phases occurred in the alloy in the as cast state. The morphology and size of the Mg2Si was also possible to determine as well the lattice parameters for this phase.Findings: : The reason of this work was also to present the laser treatment technology, which will be used for further alloying and remelting with ceramic powders – especially carbides and oxides. Particularly the overview will be directed on the laser power to achieve good layer hardness for protection of this hot work tool steel from losing their work stability and to make the tool surface more resistant to action in external conditions. The structure of the surface laser tray changes in a way, that there are very high roughness of the surface zone and the flatness or geometry changes in an important manner, crucial for further investigation.Research limitations/implications: The aluminium samples were examined metallographically using transmission electron microscope with different image techniques.Practical implications: Developing of new technology with appliance of Al alloys, High Power Diode Laser and diverse ceramic powders will be possible to obtain, based in findings from this research project. Some other investigation should be performed in the future, but the knowledge found in this research concerning the proper process parameters for each type of alloy shows an interesting investigation direction.Originality/value: The combination of metallographic investigation for cast aluminium alloys - including electron microscope investigation - and HPDL treatment parameters makes the investigation very attractive for automobile, aviation industry, and others where aluminium alloys plays an important role.

  18. Alloy dissolution in argon stirred steel

    Science.gov (United States)

    Webber, Darryl Scott

    Alloying is required for the production of all steel products from small castings to large beams. Addition of large quantities of bulk alloys can result in alloy segregation and inconsistent alloy recovery. The objective of this research was to better understand alloy dissolution in liquid steel especially as it relates to Missouri S&Ts' patented continuous steelmaking process. A 45-kilogram capacity ladle with a single porous plug was used to evaluate the effect of four experimental factors on alloy dissolution: alloy species, alloy size or form, argon flow rate, and furnace tap temperature. Four alloys were tested experimentally including Class I low carbon ferromanganese, nickel and tin (as a surrogate for low melting alloys) and Class II ferroniobium. The alloys ranged in size and form from granular to 30 mm diameter lumps. Experimental results were evaluated using a theoretically based numerical model for the steel shell period, alloy mixing (Class I) and alloy dissolution (Class II). A CFD model of the experimental ladle was used to understand steel motion in the ladle and to provide steel velocity magnitudes for the numerical steel shell model. Experiments and modeling confirmed that smaller sized alloys have shorter steel shell periods and homogenize faster than larger particles. Increasing the argon flow rate shortened mixing times and reduced the delay between alloy addition and the first appearance of alloy in the melt. In addition, for every five degree increase in steel bath temperature the steel shell period was shortened by approximately four percent. Class II ferroniobium alloy dissolution was an order of magnitude slower than Class I alloy mixing.

  19. Mechanical alloying of Ti-Al-Nb alloys

    International Nuclear Information System (INIS)

    This paper reports on Ti-Al-Nb ternary alloys containing 24Al-11Nb, 25Al-25Nb, 37.5Al-12.5Nb, and 28.5Al-23.9Nb (at.%) which were mechanically alloyed in a SPEX 8000 mixer mill using a ball-to-powder ratio of 10:1. The structural evolution in these alloys was investigated by X-ray diffraction and transmission electron microscopy techniques. In addition to forming a solid solution of Al and Nb in Ti at an early stage of milling, the B2 and amorphout phases were produced at longer milling times. Milling beyond the amorphous phase formation resulted in the formation of an fcc phase in all the alloys. The stability of these phases and their transformation to other phases have been investigated by heat treating these powders at different temperatures. The B2 phase transformed into an orthorhombic (O) or a mixture of the orthorhombic (O) and tetragonal (?) phases, depending on the alloy composition. some critical experiments were carried out to identify the nature of the fcc phase formed at the later stages of milling. It appears that this may be due to TiN formation during milling, but the nitrogen content in milled powders is less than that required for TiN formation

  20. Synthesis of Cu-Zn alloys by mechanical alloying

    International Nuclear Information System (INIS)

    A series of alloys Cu-30% Zn, Cu-49% Zn, Cu-62% Zn and Cu-83% Zn in the composition range of the phases ?,?,? and ?, respectively, were prepared by milling in a high energy ball planetary mill. The DRX results show that the full conversion of the mixtures of copper and zinc powders in the proper stoichiometric proportions in the above alloys occurs in less than 3 hours. The evolution of the intermediate phases formed as a function of the grinding time shows that the speed of formation of the alloy by mechanical treatment is controlled by the diffusion of the copper in the zinc matrix, with increased Vickers micro-hardness of the powders when the milling time increases. The SEM mapping studies show that grinding times below 10 minutes are needed to obtain a homogenous distribution of the copper and zinc. However, the DRX and SEM characterizations of the extrusion consolidated materials shows that the prior formation of a homogenous phase is needed in the starting powders in order to obtain the alloy with the desired composition in the extruded product, otherwise a segregation of the copper occurs after extruding. The DRX studies of a sample Cu-49% Zn alloyed by milling until the formation of a single ?' phase show that starting at 330oC the zinc slowly evaporates until a homogenous phase with phase ? structure forms (CW)

  1. Electrospark alloying of steel with alloys of the Nb-Zr-B system

    International Nuclear Information System (INIS)

    Erosion characteristics of alloys of the Nb-Zr-B system regularities of the strengthened layer formation during alloying with these alloys are studied. It is determined that the alloys with 35-55 mass % Nb are characterized by the maximum coefficient of transfer and minimum erosion. Strengthening of steel substrates with them permits obtaining layers of high hardness and solidity

  2. Plasma surface alloying of spheroidal graphite iron

    Energy Technology Data Exchange (ETDEWEB)

    He Zhiyong; Zhao Jinxiang; Xu Zhong [Taiyuan Univ. of Technol., SX (China). Res. Inst. of Surface Eng.

    2000-09-01

    Spheroidal graphite iron is chosen as a substrate material on which plasma W-Mo and Ni-Cr surface alloying are carried out by the Xu-Tec process. The experimental results show that W-Mo surface alloying increases the surface hardness of the cast iron from approximately 200 to 1500 HV while Ni-Cr alloying enhances the surface hardness to 600 HV or above and also the corrosion-resistance of the cast iron. The alloy content and hardness of the alloyed layer manifest a gradually decreasing tendency from surface to the inside of the substrate, an ideal profile which is beneficial to the cohesion of the surface modification layer with the bulk material. The microstructures, alloy contents and surface hardnesses of the alloyed layers are presented. Effects of processing conditions and carbon, silicon content of the specimens on the alloying results are also discussed. (orig.)

  3. Spectrochemical Investigation of Aluminum Master Alloys

    Directory of Open Access Journals (Sweden)

    Naveed Akhtar

    2010-12-01

    Full Text Available The objective of this study is to observe the significance of sampling fractions in spectrochemical analysis of aluminium master alloys. Aluminium master alloys are difficult to analyze by routine analytical methods due to inhomogeneity and high percentage of the alloying elements. In this study aluminium master alloys were remelted along with aluminium ingots of 99.9% purity in an electrical crucible furnace and subsequently analysis by spark optical emission spectrometer (OES. The bulk samples of a particular aluminium master alloy for re-melting process was chosen by two different methods and evaluated for % recovery of the target element. It was observed that sampling fractions and compilation techniques greatly affects the compositional results of aluminium master alloys. The 20% bulk sampling showed good recoveries and very precise results for each alloying element in the respective master alloy. The results of spark OES were cross checked by X-ray fluorescence spectrometer (XRF with the help of certified reference materials.

  4. The comparison of corrosion resistance between Baosteel's alloy 690 tube and foreign alloy 690 tube

    International Nuclear Information System (INIS)

    Alloy 690 having excellent corrosion resistance is widely used for SG tubes. The intergranular corrosion and pitting corrosion resistance of Baosteel's alloy 690 tube, Country A alloy 690 tube and Country B alloy 690 tube have been analysed by comparison. It shows that: The intergranular corrosion of Baosteel's alloy 690 tube tested complied with ASTM G28 Standard could satisfy the technical requirement. However.some of Baosteel's alloy 690 tube in intergranular corrosion resistance had less performance than Country A. In addition, pitting corrosion tested with ASTM G48 Standard shown the Baosteel's alloy 690 tube better than Country B. (authors)

  5. Shape memory alloys. Ultralow-fatigue shape memory alloy films.

    Science.gov (United States)

    Chluba, Christoph; Ge, Wenwei; Lima de Miranda, Rodrigo; Strobel, Julian; Kienle, Lorenz; Quandt, Eckhard; Wuttig, Manfred

    2015-05-29

    Functional shape memory alloys need to operate reversibly and repeatedly. Quantitative measures of reversibility include the relative volume change of the participating phases and compatibility matrices for twinning. But no similar argument is known for repeatability. This is especially crucial for many future applications, such as artificial heart valves or elastocaloric cooling, in which more than 10 million transformation cycles will be required. We report on the discovery of an ultralow-fatigue shape memory alloy film system based on TiNiCu that allows at least 10 million transformation cycles. We found that these films contain Ti2Cu precipitates embedded in the base alloy that serve as sentinels to ensure complete and reproducible transformation in the course of each memory cycle. PMID:26023135

  6. Fretting corrosion in orthopaedic alloys.

    Science.gov (United States)

    Cook, S D; Gianoli, G J; Clemow, A J; Haddad, R J

    Fretting corrosion, a mechanical-chemical phenomenon, most often occurs at screwhead-plate countersink junctions of internal fixation devices. An apparatus was constructed which would simulate the conditions of fretting corrosion in vivo. Fretting corrosion was studied as a function of the number of cycles and the solution in which the fretting occurred. The solutions studied were 0.9% physiological saline and a saline plus 0.5% albumin solution. The implant materials tested were Co-Cr-Mo alloy, 316L stainless steel, and Ti-6A1-4V alloy. The results demonstrated that weight loss increased with the number of fretting cycles but reached a plateau where further weight loss was negligible. Co-Cr-Mo alloy showed less weight loss than 316L stainless steel at any number of cycles. Weight loss for Ti-6A1-4V alloy was similar to Co-Cr-Mo alloy although marked abrasion was noted. All of the materials showed a marked decrease in weight loss when tested in the saline plus albumin solution as compared to the saline only solution. PMID:6679798

  7. Zinc alloy enhances strength and creep resistance

    Energy Technology Data Exchange (ETDEWEB)

    Machler, M. [Fisher Gauge Ltd., Peterborough, Ontario (Canada). Fishercast Div.

    1996-10-01

    A family of high-performance ternary zinc-copper-aluminum alloys has been developed that provides higher strength, hardness, and creep resistance than the traditional zinc-aluminum alloys Zamak 3, Zamak 5, and ZA-8. Designated ACuZinc, mechanical properties comparable to those of more expensive materials make it suitable for high-load applications and those at elevated temperatures. This article describes the alloy`s composition, properties, and historical development.

  8. Design optimization of shape memory alloy structures:

    OpenAIRE

    Langelaar, M.

    2006-01-01

    This thesis explores the possibilities of design optimization techniques for designing shape memory alloy structures. Shape memory alloys are materials which, after deformation, can recover their initial shape when heated. This effect can be used for actuation. Emerging applications for shape memory alloys are e.g. miniaturized medical instruments with embedded actuation, as well as microsystem components. However, designing effective shape memory alloy structures is a challenging task, due t...

  9. CORROSION RESISTANCE OF ALUMINUM-LITHIUM ALLOYS

    OpenAIRE

    Lin, F.; Moji, Y.; Quist, W.; Badger, D.

    1987-01-01

    The effects of corrosive environments on aluminum-lithium-copper-(magnesium) alloys have been studied as they relate to the commercial airplane industry. It has been found that, in general, the alloys 2090 and 2091 exhibit equal or improved corrosion performance compared to the 2024 and 7075 alloys they are likely to replace. Cladding and coating systems have been shown to compare favorably with conventional alloys.

  10. Self hardening aluminum alloys for automotive applications

    OpenAIRE

    Castella, Christian

    2015-01-01

    Self-hardening aluminum alloys (Al-Zn-Si-Mg alloys) represent an innovative class of light aluminum alloys. They present high mechanical properties, which make them suitable for many applications in different industrial fields, especially in transport industry. The most important and relevant feature of the self-hardening alloys is related to their good performance, without the need of any heat treatment: they are subjected to a natural ageing phenomenon at room temperature after a storage pe...

  11. Spectrochemical Investigation of Aluminum Master Alloys

    OpenAIRE

    Naveed Akhtar

    2010-01-01

    The objective of this study is to observe the significance of sampling fractions in spectrochemical analysis of aluminium master alloys. Aluminium master alloys are difficult to analyze by routine analytical methods due to inhomogeneity and high percentage of the alloying elements. In this study aluminium master alloys were remelted along with aluminium ingots of 99.9% purity in an electrical crucible furnace and subsequently analysis by spark optical emission spectrometer (OES). The bulk sam...

  12. Synthesis of nanocrystalline carbide in tungsten alloy by mechanical alloying and annealing

    International Nuclear Information System (INIS)

    Amorphous tungsten alloys embedded with nanocrystalline carbide were obtained through crystallization of a completely amorphized tungsten alloy, which has first been synthesized by mechanical alloying. Structural characterization, showed the formation of amorphous structure after mechanical alloying a mixture of elemental tungsten and iron powders for about 150 h. Partial nanocrystalline phases within the amorphous matrix were formed through annealing the amorphous tungsten alloy at 1075 deg. C

  13. The structural study of Ti-Si-C alloys produced by mechanical alloying method

    OpenAIRE

    W. PIlarczyk; R. Nowosielski; Pilarczyk, A

    2009-01-01

    Purpose: The aim of this paper is to determine the influence of the alloying time and composition on the structure of Ti-Si-C alloy.Design/methodology/approach: The powders of the Ti-Si-C alloys were obtained by mechanical alloying method in a planetary Fritsh Pulverisette 5 mill under inert argon atmosphere. In order to investigate the structure scanning electron microscopy, transmission electron microscopy and optical microscopy were used. Phase transformations during mechanical alloying pr...

  14. Improved thermal treatment of aluminum alloy 7075

    Science.gov (United States)

    Cocks, F. H.

    1968-01-01

    Newly developed tempering treatment considerably increases the corrosion resistance of 7075-T6 alloy and concomitantly preserves its yield strength. The results of tests on samples of the alloy subjected to the above treatments show that when the overaging period is 12 hours /at 325 degrees F/, the alloy exhibits a yield strength of 73,000 psi.

  15. High strength uranium-tungsten alloys

    Science.gov (United States)

    Dunn, Paul S. (Santa Fe, NM); Sheinberg, Haskell (Los Alamos, NM); Hogan, Billy M. (Los Alamos, NM); Lewis, Homer D. (Bayfield, CO); Dickinson, James M. (Los Alamos, NM)

    1991-01-01

    Alloys of uranium and tungsten and a method for making the alloys. The amount of tungsten present in the alloys is from about 4 wt % to about 35 wt %. Tungsten particles are dispersed throughout the uranium and a small amount of tungsten is dissolved in the uranium.

  16. Aluminum alloy suitable for pistons

    International Nuclear Information System (INIS)

    This patent describes improvement in the manufacture of a combustion engine component wherein the component is made from an aluminum alloy. The improvement wherein the alloy is provided as an alloy consisting essentially of 9.0 to less than 14 wt. % Si, 3.0 to 7.0 wt. % Ni, 1.5 to 6.0 wt. % Cu, 0.005 to 0.3 wt % Sr, at least one of the elements selected from Mg, Mn, V, Sc, Fe, Ti, Zn, B and Cr. The element having the ranges: 0.8 wt. % Mg max., 1 wt. % Mn Max., 0.3 wt. % V max., 0.3 wt. %Sc max., 0.25 wt. % Ti max., up to 0.2 wt. % B, up to 0.2 wt. % Cr, 0.5 wt. % Zn max. and 0.8 wt. % Fe max, the remainder aluminum and impurities

  17. Radiation damage in titanium alloys

    International Nuclear Information System (INIS)

    Titanium alloys are among materials being considered for the first wall and blanket structure of a fusion reactor. A description is presented of the crystallographic features of the neutron-radiation-induced defect structure, radiation-induced precipitation of nonequilibrium phases, and annealing of damage microstructure determined by transmission electron microscopic examination of variously heat-treated alpha-beta, alpha, and beta-titanium alloys irradiated to a fluence of 3 x 10 to the 21st neutrons/sq cm. It was found that high-energy neutron irradiation of Ti-6Al-4V results in extensive defect clusters, prismatic loops along with fine, ellipsoidal, 10-20 nm beta precipitates. The beta precipitates redissolve upon annealing the irradiated alloy at 650 C. The causes of beta precipitation were identified to be radiation-enhanced diffusion and radiation-induced segregation of the undersized beta stabilizing element, vanadium, to the defect clusters

  18. Magnesium and related low alloys

    International Nuclear Information System (INIS)

    In the first part the authors examine the comparative corrosion of commercial magnesium, of a magnesium-zirconium alloy (0,4 per cent ? Zr ? 0,7 per cent) of a ternary magnesium-zinc-zirconium alloy (0,8 per cent ? Zn ? 1,2 per cent) and of english 'Magnox type' alloys, in dry carbon dioxide-free air, in damp carbon dioxide-free air, and in dry and damp carbon dioxide, at temperatures from 300 to 600 deg. C. In the second part the structural stability of these materials is studied after annealings, of 10 to 1000 hours at 300 to 450 deg. C. Variations in grain after these heat treatments and mechanical stretching properties at room temperature are presented. Finally various creep rate and life time diagrams are given for these materials, for temperatures ranging from 300 to 450 deg. C. (author)

  19. Hydrogen effects in aluminum alloys

    International Nuclear Information System (INIS)

    The permeability of six commercial aluminum alloys to deuterium and tritium was determined by several techniques. Surface films inhibited permeation under most conditions; however, contact with lithium deuteride during the tests minimized the surface effects. Under these conditions phi/sub D2/ = 1.9 x 10-2 exp (--22,400/RT) cc (NTP)atm/sup --1/2/ s-1cm-1. The six alloys were also tested before, during, and after exposure to high pressure hydrogen, and no hydrogen-induced effects on the tensile properties were observed

  20. Theoretical studies of metallic alloys

    International Nuclear Information System (INIS)

    A new method to predict and understand the structure and phase stability of solid-solution alloys from a knowledge only of the atomic numbers of the constituent atoms is being developed. The coherent potential approximation will be used to obtain the electronic contribution to the energy and the Monte Carlo method of statistical mechanics will be used for the thermodynamic part of the calculation. An improved coherent potential approximation will be developed by combining the standard approach with the quadratic KKR (QKKR) band theory method. This will make it easier to predict the properties of alloys from first principles. The QKKR method will be developed further