Energy Technology Data Exchange (ETDEWEB)

The resistance to pitting of a Fe-17%Cr alloy in Cl[sup [minus

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Papers are presented on the development of oxidation- and sulfidation-resistant ferritic alloys; the microstructural stability of sulfidation-resistant FeCrAl stainless steels around 500 C; age hardening in Fe-Mn-Al-C austenitic alloys; the oxidation/corrosion behavior of low-Cr Fe-Cr-Ni alloys containing Zr or Nb; the high temperature oxidation/corrosion of iron-based superalloys; and the role of Mo in the Na/sub 2/SO/sub 4/ induced corrosion of superalloys at high temperature. Topics discussed include the effect of variations of Co content on the cyclic oxidation resistance of selected Ni-base superalloys; high temperature oxidation of Fe based alloys; the morphological development of high temperature oxide scales of Fe-Mn-Al base alloys; and the oxidation of an ...

Energy Technology Data Exchange (ETDEWEB)

Million-atom molecular-dynamics (MD) simulations are performed to study the structure, mechanical properties, and dynamic fracture in nanophase Si{sub 3}N{sub 4}. The authors find that intercluster regions are highly disordered: 50% of Si atoms in intercluster regions are three-fold coordinated. Elastic moduli of nanophase Si{sub 3}N{sub 4} as a function of grain size and porosity are well described by a multiphase model for heterogeneous materials. The study of fracture in the nanophase Si{sub 3}N{sub 4} reveals that the system can sustain an order-of-magnitude larger external load than crystalline Si{sub 3}N{sub 4}. This is due to branching and pinning of the crack front by nanoscale microstructures.

Energy Technology Data Exchange (ETDEWEB)

FeSi{sub 6}/graphite composite was prepared by mechanical ball milling. The FeSi{sub 6} alloy particles consist of an electrochemically active silicon phase and inactive phases FeSi{sub 2}, distributed uniformly in the graphite matrix. The composite anode offers a large reversible capacity (about 800 mAh g{sup -1}) and good cycleability, due to the buffering effect of the inactive FeSi{sub 2} phase and graphite layers on the volumetric changes of Si phase during lithium-Si alloying reaction. Since FeSi{sub 6} alloy is a low-cost industrial material, this alloy compound provides a possible alternative for development of high capacity lithium-ion batteries. (author)

Energy Technology Data Exchange (ETDEWEB)

It has been clarified by the present authors, based on the plasma nitriding of Fe-Cr alloys and Fe-Ti alloys carried out at the temperature under 550{degree}C hitherto, that an internal nitriding layer is formed due to the fine dispersion of the particles of Cr nitride and Ti nitride in {gamma}{prime} Fe4N layer on the specimen surface. In this study, the plasma nitriding of Fe-Cr alloys are carried out at 650{degree}C, and the effects of the solute (Cr) content on the structures, nitride and the thickness distribution are examined. The main results obtained therefrom are indicated hereafter. In accordance with the observation on the cross-sectional structure of the alloys, only the nitriding layer deduced as the dispersion and precipitation of the particles of Cr nitride from {alpha}-Fe of the ...

International Nuclear Information System (INIS)

The study of passive films formed on a nickel base alloy type Inconel 600 is performed by capacitance measurements (Mott-Schottky approach). This research is supported by the passivation study of the alloying elements Ni, Cr, Fe and high purity alloys Ni-Cr, Ni-Fe, Ni-Cr-Fe. The results obtained show that the capacitive behaviour of the Inconel 600 in the passive state is similar to that on a p-n heterojunction to which a barrier zone of nickel oxide is added. The individual or combined action of alloying elements on the development of this kind of electronic structure is discussed. (authors). 5 refs., 6 figs.

British Library Electronic Table of Contents (United Kingdom)

Gas nitridation has shown excellent promise to form dense, electrically conductive and corrosion-resistant Cr-nitride surface layers on Ni-Cr base alloys for use as proton exchange membrane fuel cell (PEMFC) bipolar plates. Due to the high cost of nickel, Fe-base bipolar plate alloys are needed to meet the cost targets for many PEMFC applications. Unfortunately, nitridation of Fe-base stainless steel alloys typically leads to internal Cr-nitride precipitation rather than the desired protective surface nitride layer formation, due to the high permeability of nitrogen in these alloys. This paper reports the finding that it is possible to form a continuous, protective Cr-nitride (CrN and Cr2N) surface layer through nitridation of Fe-base stainless steel alloys. The key to form a protective Cr...

International Nuclear Information System (INIS)

Substantial roles of precipitates such as Zr-Fe-Cr type intermetallic compounds on uniform corrosion and hydrogen pickup of zirconium alloys in pure water autoclave tests were investigated from an electrochemical point of view. In the previous paper, corrosion mechanism was elucidated by the anodic protection-precipitates degradation model. This paper describes the roles on hydrogen pickup. 633 K pure water autoclave test was performed on high purity zirconium, Zr-0.2Fe, Zr-0.2Cr, and Zr-0.1Fe-0.1Cr alloys. Hydrogen analysis after the corrosion test showed that hydrogen pickup ratio of Zr-0.2Fe alloy was about 80%. It was much higher than about 30% of pure Zr and about 10% of both Zr-0.2Cr and Zr-0.1Fe-0.1Cr alloys. Larger hydrogen content was introduced into Zr-0.2Fe ...

International Nuclear Information System (INIS)

Substantial roles of precipitates such as Zr-Fe-Cr type intermetallic compounds on uniform corrosion and hydrogen pickup of zirconium alloys in pure water autoclave tests were investigated from an electrochemical point of view. This paper describes the roles on corrosion. A corrosion test on precipitate-containing and precipitate-free materials made from pure zirconium and a small quantity of iron and chromium, rest potential measurements on an intermetallic compound of Zr(FeCr)_2 and zirconium matrix, and a galvanic coupling test of those were performed. Results showed that corrosion behavior of zirconium alloys could be attributed to the electrochemical properties of intermetallic compounds precipitated in each alloy. Namely, the cathodic and anodic polarization characteristics were associated with anodic protection provided by the precipitates on the alloys ...

International Nuclear Information System (INIS)

The carbothermal reduction of clay minerals in a nitrogen atmosphere is a well established method for producing #beta#'-sialon. There has been some debate within the literature concerning the role that Fe plays in the formation of the #beta#'-sialon phase. However, most workers accept that Fe is able to either catalyze or promote the formation of #beta#'-sialon although some workers have indicated that the function of the Fe is controlled by gas flow rate and there is evidence that Fe also promotes formation of additional phases. The aim of the present study was to characterize the behaviour of Fe within the #beta#'-sialon synthesis. "5"7Fe Moessbauer spectroscopy was employed for the study because this technique is specific to Fe and does not suffer interference from other elements. Moreover, both the coordination and oxidation state and ...

International Nuclear Information System (INIS)

... Sergio Department of Materials, University of Oxford, Oxford (United Kingdom)

Energy Technology Data Exchange (ETDEWEB)

The transformation from the as-quenched amorphous to the crystalline state in Fe/sub 78/B/sub 13/Si/sub 9/ alloy has been investigated using a new-type neutron diffractometer. The time resolved diffraction patterns clearly show that this alloy crystallizes into FeSi alloy and Fe/sub 2/B in that order. The time evolution of these crystalline phases can be analyzed by the Kolmogorov-Johnson-Mehl-Avrami equation with the exponent of about 2.5 over a wide temperature range. This suggests that the crystallization occurs by the diffusion-controlled growth with a constant nucleation rate. The scaling behavior in the crystallization kinetics is also discussed.

British Library Electronic Table of Contents (United Kingdom)

Ceramic coatings with high emission were fabricated on Ti6Al4V alloy by microarc oxidation (MAO) with additive FeSO4 into the electrolyte. The microstructure, chemical composition and chemical state of the coatings were determined by SEM, XRD, EDS and XPS, respectively. The bonding strength between the coating and substrate was studied by tensile strength test, together with the thermal shock resistance of the coating. The results showed that Fe content in the coating layer significantly affect its thermal emissivity. The relative content of Fe in the coatings surface increased at first and then decreased with increasing the concentration of FeSO4 in electrolytes, so does the emissivity of the coatings. The bonding strength became weaker with increasing the concentration of FeSO4. In addit...

International Nuclear Information System (INIS)

Conventional methods for reducing vibration in engineering designs (i.e. by stiffening or detuning) may be undesirable or inadequate in conditions where size or weight must be minimized or where complex vibration spectra exist. Alloys which combine high damping capacity with good mechanical properties can provide attractive technical and economic solutions to problems involving seismic, shock and vibration isolation. To meet these trends, we have developed a new high damping Fe-17%Mn alloy. Also, the alloy has advantages of good mechanical properties and is more economical than any other known damping alloys (a quarter the cost of non-ferrous damping alloy). Thus, the high damping Fe-17%Mn alloy can be widely applied to household appliances, automobiles, industrial facilities and power plant components with its excellent ...

British Library Electronic Table of Contents (United Kingdom)

In the present work, bulk amorphous and nanocrystalline Al83Fe17 alloys were obtained by consolidation of mechanically alloyed powders. Mechanical alloying of Al-17% Fe powder mixture yielded powder with an amorphous structure. Thermal behaviour of the milling product was examined using differential scanning calorimetry. This investigation revealed that the amorphous phase crystallised above 380^oC. The amorphous powder was compacted under a pressure of 7.7GPa in different conditions: at 380^oC for 600s and at 1000^oC for 180s. Structural investigations of the bulk material revealed that the amorphous structure was retained after consolidation process applied at 380^oC. Compaction under high pressure at 1000^oC caused crystallisation of the amorphous phase and appearance of metastable nano...

Energy Technology Data Exchange (ETDEWEB)

An analysis of the passive films formed on amorphous alloys of the system Fe-10% Cr-5% Mo-P-metalloid and Fe-10% Cr-5% Mo-B-Si revealed that they are more markedly enriched with chromium in silicon-free alloys. In silicon-containing amorphous alloys the passive films were highly enriched with silicon, which occurred in these films in the form of a corrosion product close to SiO/sub 2/. As shown by the investigations of a study of the anodic behavior of Fe/sub 40/Ni/sub 40/P/sub 14/B/sub 6/ and Fe/sub 40/Ni/sub 38/Mo/sub 4/B/sub 18/, phosphorus facilitates the passivation of amorphous alloys by reducing the solution current in the active state and enriching the surface layers of the metal in the form of a black prepassivation film which also contains nickel and iron. The behavior of Fe-Ni amorphous ...

Energy Technology Data Exchange (ETDEWEB)

Corrosion of several materials including pure metals Fe, Ni, Cr and also Fe-Cr, Fe-Ni-Cr alloys, has been studied in anisothermal Pb17Li (Tmax = 500 deg C; {Delta}T = 60 deg C). The corrosion rate of pure nickel is two orders of magnitude higher than the chromium one and about three orders of magnitude higher than the iron one. Fe-Cr alloys (1.4914) suffers a dissolution rate equal to the one of its major constituent, iron. With regard to the three austenitic materials (316L and NS20 steels, alloy 800), they exhibit a porous corrosion layer mainly constituted of ferrite but containing also a small amount of {sigma} phase in the case of the alloys with higher Ni content, NS30 steel and alloy 800. Mechanism of formation of this layer is discussed.

International Nuclear Information System (INIS)

Surface analytical studies of high nitrogen austenitic stainless steels exposed to deaerated 0.1M HCl have revealed that nitrogen alloying additions influence the composition of salt layers and the passive film/alloy interface. In this study the authors employ electrochemical techniques and variable angle X-ray Photoelectron Spectroscopy (XPS) to examine the passive films formed on a series of austenitic stainless steels, Fe18Cr8Ni, Fe18Cr8Ni0.2N, Fe20Cr20Ni, Fe20Cr20Ni6Mo and Fe20Cr20Ni6Mo0.2N, in acidic chloride aqueous solution. In addition, several other model alloys, Fe19Cr, Fe19Cr9Ni, Fe19Cr2.5Mo, and Fe19Cr9Ni2.5Mo, were examined before and after electrochemical surface nitriding, a technique proven to have an effect analogous to N ...

International Nuclear Information System (INIS)

K#beta#-to-K#alpha# x-ray intensity ratios of Fe and Ni in pure metals and in Fe_xNi_1_-_x alloys (x=0.20, 0.50, 0.58) exhibiting similar crystalline structure have been measured following excitation by 59.54 keV #gamma# rays from a 200 mCi "2"4"1Am point source to understand why the properties of the Fe_xNi_1_-_x (x=0.2) alloy are distinct from other alloy compositions. The valence electronic structure of Fe and Ni in the samples has been evaluated by comparing the measured K#beta#-to-K#alpha# intensity ratios with the results of multiconfiguration Dirac-Fock calculations. Significant changes in the 3d electron population (with respect to the pure metal) are observed for Fe and Ni for certain alloy compositions. These changes can be explained by assuming rearrangement of electrons between 3d and ...

Energy Technology Data Exchange (ETDEWEB)

Chemical phase identifications of complex, multilayered corrosion products formed on Fe-Ni-Cr alloys immersed in molten NaNO/sub 3/-KNO/sub 3/ and LiNO/sub 3/-NaNO/sub 3/-KNO/sub 3/ were obtained by X-ray diffraction analysis. Diffraction analyses performed after successive material removal steps provided depth profiles of corrosion products and identified the dominant phases as NaFeO/sub 2/, Fe/sub 3/O/sub 4/, and Cr/sub 2/O/sub 3/ for Alloy 800 and 316SS after immersion in NaNO/sub 3/-KNO/sub 3/. In LiNO/sub 3/-NaNO/sub 3/-KNO/sub 3/, the major corrosion products identified on Alloy 800 were LiFeO/sub 2/, Fe/sub 3/O/sub 4/, and Cr/sub 2/O/sub 3/. X-ray diffraction results were supplemented by electron microprobe analyses that revealed the solid solution nature of several of the oxide phases.

International Nuclear Information System (INIS)

To clarify the acidic and alkaline Intergranular Stress Corrosion Cracking (IGSCC) mechanism of thermally treated alloy 690 (alloy 690 TT) and shot peened alloy 800 (alloy 800 SP), C-ring tests were conducted in deaerated HCl solutions and in deaerated NaOH solutions at 350degC, compared with the acidic and the alkaline IGSCC susceptibilities of mill-annealed alloy 600 (alloy 600 MA), full-sensitized one (alloy 600 FS) and thermally treated one (alloy 600 TT). Grain boundary characteristics, such as chromium depleted zone and chromium carbide precipitation, were examined using modified Huey test and Transmission Electron Microscopy. Potential-pH diagram for Ni, Cr, Fe-H_2O system at 350degC was constructed and the solubilities of NiO, Cr_2O_3 and Fe_3O_4 were also calculated to ...

Energy Technology Data Exchange (ETDEWEB)

The study of passive films formed on a nickel base alloy type Inconel 600 is performed by capacitance measurements (Mott-Schottky approach). This research is supported by the passivation study of the alloying elements Ni, Cr, Fe and high purity alloys Ni-Cr, Ni-Fe, Ni-Cr-Fe. The results obtained show that the capacitive behaviour of the Inconel 600 in the passive state is similar to that on a p-n heterojunction to which a barrier zone of nickel oxide is added. The individual or combined action of alloying elements on the development of this kind of electronic structure is discussed. (authors). 5 refs., 6 figs.

Energy Technology Data Exchange (ETDEWEB)

The nickel-rich superalloys Alloy 600 and Alloy 800 have been corroded in mildly alkaline deuterated aqueous conditions typical of secondary coolant circuits in a nuclear power station. The oxide films and substrates of these alloys have been analysed by imaging SIMS depth profiling, which makes it possible to describe elemental distribution in all three dimensions. The measurement of the distribution of the secondary ions NiO[sup -], FeO[sup -] and CrO[sup -] appears useful for detailing the behaviour of nickel, iron and chromium within oxidized phases. The measurement of D[sup -] distribution outlines the extent of oxide hydration. For Alloy 800, evidence of sodium migration into the grain boundaries of the alloy substrate is found. For Alloy 600, no grain boundary sodium ingress can be identified under comparable corrosion conditions. ...

International Nuclear Information System (INIS)

Photoelectrochemical current response of passive film was investigated for pure Cr and Fe-xCr (x = 8, 14, 18) alloys polarised potentiostatically in 0.1 kmol m"-"3 H_2SO_4 solution. Photoelectrochemical action spectrum could be separated into two or three constituents. These components were considered to be derived from Cr_2O_3 (E_g"o"p"t#propor to#3.6 eV) and Cr(OH)_3 (E_g"o"p"t#propor to#2.5 eV), and possibly CrO OH. The optical band gap, E_g"o"p"t, of each component was almost constant for various applied potentials, polarisation periods, and substrate materials. Flat band potential E_j_b at which the polarity of photocurrent changes from negative to positive with increasing potential was determined for each phase. E_j_b for Cr(OH)_3 on Cr and Fe-Cr alloys was about 250 mV_A_g_/_A_g_C_l. E_j_b for Cr_2O_3 was about 700 mV for Cr and about 500 mV for Fe-Cr ...

Energy Technology Data Exchange (ETDEWEB)

The purpose of this work was to investigate the role of chromium on hydrogen embrittlement of Ni-Cr-Fe alloys and thus to develop a better understanding of the low-temperature stress corrosion cracking (SCC) phenomenon. The effect of chromium on hydrogen embrittlement was examined using tensile tests followed by material evaluation via scanning electron microscopy (SEM) and light optical microscopy. Four alloys were prepared with chromium contents ranging from 6 to 35 wt pct. In the uncharged condition, ductility, as measured by the percent elongation or reduction in area, increased as the alloy chromium content increased. Hydrogen appeared to have only minor effects on the mechanical properties of the low-chromium alloys. The addition of hydrogen had a marked effect on the ductility of the higher-chromium alloys. In the 26 pct chromium ...

International Nuclear Information System (INIS)

A new high strength titanium alloy has been developed primarily intended for fastener applications. While Ti-6Al-4V is used extensively as a fastener alloy in the aerospace industry, its shear strength allowable is limited to 655 MPa (95 ksi). For higher shear strength requirements, various steels or nickel-based alloys are used (up to 860 MPa (125 ksi)), but with the attendant density penalty. This new alloy is intended to provide the 860 MPa shear strength at roughly a 40% weight savings. After screening various alloy systems, the optimum chemistry has been selected as follows: Ti-6.0V-6.2Mo-5.7Fe-3Al. In light of its 125 ksi shear strength goal, the alloy has been designated TIMETAL reg-sign 125.

Energy Technology Data Exchange (ETDEWEB)

Alloy 800 is an austenitic Fe-Ni-Cr steel containing relatively minor but important amounts of carbon, aluminium and titanium. Special grades of alloy 800 known as 800H, 800HT and 800LC differ in the concentrations of these elements. In addition to these industrial specifications, further melts were prepared containing phosphorous or sulphur. Using a radioactive tracer method the bulk and grain-boundary diffusion of {sup 59}Fe was investigated in these alloys in the temperature range 800 to 1000 C. For evaluation of the diffusion profiles the approximation of Suzuoka was used, which considers the depletion of the tracer on the surface. By autoradiography it was confirmed that such depletion occurs. In alloy 800H the activation energy of grain-boundary diffusion of {sup 59}Fe was found to be (209{+-}17) kJ/mol; dissolved elements, especially ...

Energy Technology Data Exchange (ETDEWEB)

Using a radioactive tracer method the bulk and grain boundary diffusion of {sup 59}Fe was determined in industrial alloy 800 and melts of alloy 800 with additional P and S in the temperature range 800 to 1000 C. The use of the approximation of Suzuoka was confirmed by autoradiographs. In alloy 800 H the activation energy of grain boundary diffusion of {sup 59}Fe is (209 {+-} 17)kJ/mol. Dissolved elements especially P increase the activation energy of the grain boundary diffusion of Fe by their segregation to the grain boundaries. In addition the influence of the grain boundary diffusion on the growth of creep cavities was investigated in the same materials, and the chemical composition of the creep cavities and grain boundaries were analysed by Auger electron spectroscopy (AES). For alloy 800 + 0.088 wt-%P an enrichment of about 14 at-%P was ...

International Nuclear Information System (INIS)

Using the full potential linearized augmented plane wave (FLAPW) method, thickness dependent magnetic anisotropy of ultrathin FeCo alloy films in the range of 1 monolayer (ML) to 5 ML coverage on Pd(0 0 1) surface has been explored. We have found that the FeCo alloy films have close to half metallic state and well-known surface enhancement in thin film magnetism is observed in Fe atom, whereas the Co has rather stable magnetic moment. However, the largest magnetic moment in Fe and Co is found at 1 ML thickness. Interestingly, it has been observed that the interface magnetic moments of Fe and Co are almost the same as those of surface elements. The similar trend exists in orbital magnetic moment. This indicates that the strong hybridization between interface FeCo alloy and Pd gives rise to the large ...

Energy Technology Data Exchange (ETDEWEB)

The pitting resistance of Fe-Cr and Fe-Cr-Mo alloys has been correlated with characteristics of the passive films analyzed by Auger electron spectroscopy (AES). Increased film protectiveness as a result of increased Cr in the alloy can be directly attributed to Cr enrichment of the film and decreased film thickness. Increased Mo in the alloy or passivation at noble potentials promotes passive film resistance to breakdown, but neither does much to change the macrocharacteristics of the film. Rather, it is suggested that the roles of alloying and/or passivation conditions are related to the susceptibility and distribution of weak points of the film. In solutions in which pitting occurs, chloride is generally not incorporated into the film, suggesting that the role of halides is to interact with weak points of the film at the solution/film interface. At 260/sup ...

International Nuclear Information System (INIS)

The possible surface enrichment of chromium and molybdenum during dissolution of Fe18Cr (110) and Fe18Cr3Mo (110) alloys at constant potentials in the passive region is elucidated by taking into account quantitative information on partial dissolution rates of alloy components as measured by #gamma#-spectrometry and on chemical composition of passivating films as measured by ESCA and AES. When combining results from all methods it is found that chromium under all conditions is enriched in the passivating films. An accumulation of chromium in the alloy is also indicated. For molybdenum, an enrichment in the passive film is observed at -0.2 V (SCE), whereas in the potential interval 0.1 - 0.9 V, the molybdenum enrichment as determined by ESCA and AES is hardly significant. On the other hand, #gamma#-spectrometry gives a clear indication of molybdenum enrichment in both potential. ...

International Nuclear Information System (INIS)

Recent advances made in the area of amorphous and nanocrystalline alloys exhibiting high saturation inductions are reviewed. A new chemical composition was identified that achieves a saturation induction of 1.64 T in an iron-based amorphous alloy. This alloy, when used in electrical transformers, shows a much improved performance over the existing amorphous alloy. Nanocrystalline FeCoCuNbSiB alloys are found to have saturation induction levels reaching 1.7 T. These materials are suited for use in sensors and inductors carrying large currents. Some of these nanocrystalline alloys show a BH squareness ratio exceeding 90%, which can be utilized in pulse power devices. Recent developments in the applications of these materials are also pointed out.

International Nuclear Information System (INIS)

Alloying elements such as Fe and Cr are generally considered to be effective even in small quantities for corrosion resistance of Zircaloy-4. The maximum total solubility of Fe + Cr in a Zr-Sn matrix has been reported to be very low. Therefore, most of these elements are observed in the form of ternary Zr-Fe-Cr-type precipitates. To clarify the effects of precipitates on corrosion property, Zr-1.3 Sn-(Fe,Cr) alloys containing Fe + Cr from 45 up to 180 ppm (the Fe to Cr ratio is about 2) were melted from pure zirconium (X-bar Zr and EB-Zr) and pure alloying elements. They were subjected to corrosion testing in 633 K water and microstructural analysis. It was found that precipitate-free materials showed much larger weight gains than precipitate-containing materials even at the same ...

International Nuclear Information System (INIS)

K#beta#-to-K#alpha# X-ray intensity ratios of Ti, Cr, Fe and Co in pure metals and in Cr_0_._2_6Fe_0_._7_4, Cr_0_._8_0Co_0_._2_0 and Ti_0_._8_0Cr_0_._2_0 alloys have been measured following excitation by 59.54 keV #gamma#-rays from a 7400 MBq (200 mCi) "2"4"1Am point-source. The valence electronic structure of Ti, Cr, Fe and Co in the samples have been evaluated by the comparison of the measured K#beta#-to-K#alpha# intensity ratios with the results of multiconfiguration Dirac-Fock calculations performed for various electronic configurations of these metals. The 3d-electron populations obtained for pure metallic Ti, Cr, Fe and Co agree well with the results of band structure calculations of Papaconstantopoulos (Handbook of band structure of elemental solids, Plenum Press, New York, 1986). Our analysis indicates significant increase of 3d-electron population of Ti, Cr and ...

International Nuclear Information System (INIS)

In the present paper the progress of optimization of soft magnetic properties have been studied by applying different experimental techniques (magnetic measurements, electric measurements, X-ray analysis, and high-resolution electron microscopy observation). It has been shown that an increase in magnetic permeability after optimization annealing can be mainly attributed to annealing out of microvoids. (author)

Energy Technology Data Exchange (ETDEWEB)

In this work, the ability of a number of Zr-containing intermetallic compounds with the Zr{sub 2}Me stoichiometry, including Zr{sub 2}Fe, Zr{sub 2}Ni, Zr{sub 2}Co and Zr{sub 4}Fe{sub 2}O{sub 0.6}, to participate in the Hydrogenation-Disproportionation-Desorption-Recombination process was investigated, revealing for the first time that the HDDR route can be employed successfully for all these compounds. 24 refs.

Energy Technology Data Exchange (ETDEWEB)

Gas nitridation has shown excellent promise to form dense, electrically conductive and corrosion-resistant Cr-nitride surface layers on Ni-Cr base alloys for use as proton exchange membrane fuel cell (PEMFC) bipolar plates. Due to the high cost of nickel, Fe-base bipolar plate alloys are needed to meet the cost targets for many PEMFC applications. Unfortunately, nitridation of Fe-base stainless steel alloys typically leads to internal Cr-nitride precipitation rather than the desired protective surface nitride layer formation, due to the high permeability of nitrogen in these alloys. This paper reports the finding that it is possible to form a continuous, protective Cr-nitride (CrN and Cr{sub 2}N) surface layer through nitridation of Fe-base stainless steel alloys. The key to form a protective Cr-nitride surface layer was ...

Energy Technology Data Exchange (ETDEWEB)

Two rapidly solidified powders with compositions Al-6.7 wt.% Fe-5.9 wt.% Ce and Al-6.2 wt.% Fe-5.9 wt.% Ce-1.63 wt.% Si were separated into -32 [mu]m and +32 to -63 [mu]m size fractions. Powders from both size fractions were extruded at 500 C. For comparison purposes, extrusion at a lower temperature of 400 C was also performed. In this investigation, tensile property evaluation indicated that processing of finer size fractions at high temperature offers no advantages in terms of the tensile properties but is advantageous in terms of improving the fracture toughness of alloy B. These observations underline the importance of the stability of powder microstructure during thermomechanical processing for the development of optimum mechanical properties. (orig.)

Energy Technology Data Exchange (ETDEWEB)

The purpose of this study is to evaluate the synergistic effect of helium and hydrogen on Fe-Cr ferritic model alloys, to provide basic understanding concerning development of fusion reactor components. Single, dual and triple ion-beams consisting of Fe{sup 3+}, He{sup +} and H{sup +} were used for irradiation, at temperatures 470-600 deg. C and dose to 50 dpa at 1 {mu}m. The dual beam irradiation with He enhanced cavity nucleation extensively to swelling of about 0.4%, whereas the dual beam irradiation with H did not significantly affect the microstructure. In the case of triple ion irradiation, the synergistic effect of He and H was confirmed clearly; relative large void formation and enhanced swelling to almost 5%. The synergistic effect suggests that the role of H is important for void growth and dislocation bias.

International Nuclear Information System (INIS)

The ductility of extruded heavy-section Ti-base--Mo--V--Fe--Al alloy was studied. Metallographic evidence for the large effect of grain size on ductility is presented. Fracture was found to occur in large-grain material after less deformation than in smaller grain size specimens.

Energy Technology Data Exchange (ETDEWEB)

A method for using in situ X-ray absorption near edge spectroscopy to determine the composition of passive, transpassive, and nonreducible thin oxide films is described. The method is demonstrated by determining the composition of the passive films formed in pH 4.5, 0.1 M acetate buffer, on 100 {angstrom} thick Fe-yCr alloys (y = 8.5, 15, 19, 23 atom %) at potentials: (1) low in the passive region ({minus}0.3 V vs. mercurous sulfate reference electrode, MSE); (2) high in the passive region; (3) in the transpassive region; and (4) in the cathodic region where the air-formed film is not fully reduced. The nonreducible film at {minus}1.2 V is entirely a Cr{sup 3+} oxide/hydroxide. This nonreducible film persists at anodic potentials. At {minus}0.3 V, the passive film on each alloy is significantly enriched in Cr. The film at {minus}0.3 V consists primarily of the nonreducible Cr{sup 3+} oxide/hydroxide plus a very small amount ...

British Library Electronic Table of Contents (United Kingdom)

The effect of Mo addition on the glass-forming ability (GFA), magnetic properties, mechanical properties and corrosion resistance of (Fe0.76Si0.096B0.084P0.06)100-xMox (x=0, 2, 4 and 6at.%) bulk glassy alloys (BGAs) with high Fe contents was investigated. The 2at.% Mo addition makes the alloy composition approach towards a eutectic point, which could result in an increase in the GFA. The BGA rod with diameters up to 3.5mm was produced by copper mold casting. These BGAs exhibit a rather high saturation magnetization of 0.98-1.51T and lower coercive force of 1.7-2.1A/m. A significant improvement in corrosion resistance was observed with microalloying Mo element in 1N H2SO4 solution. Furthermore, these Fe-based BGAs show super-high strength of ~3.3GPa and Young's modulus of 200GPa.

International Nuclear Information System (INIS)

Superplasticity in Ti alloys has been widely investigated in the past and superplastic forming of aerospace components has thus been developed over the last two decades. The Ti alloy most studied in this framework is undoubtedly the Ti-6Al-4V (wt %) alloy, for which maximum elongations are obtained in the temperature range [880-900C]. The development of the superplastic properties has been demonstrated to be in close relation with quite similar volume fractions of the #alpha# and #beta# phases, the #beta# transus temperature for this alloy ranging from 980-1000 C. Attempts have been carried out to reduce the temperature of superplastic forming of Ti-6Al-4V by the addition of elements like Fe, Co, or Ni. Such an introduction of alloying elements indeed results in a decrease of the optimum forming temperature to values as low as 820 C. This decrease is mainly ...

International Nuclear Information System (INIS)

Magnetic properties of a recently developed Fe-based amorphous alloy with a high saturation induction of 1.65 T are reviewed. The increased saturation induction is fully utilized in transformers with reduced magnetic losses, physical sizes and audible noises, minimizing some of the drawbacks of amorphous metal-based transformers based on a currently available amorphous alloy. Impacts of this on the worldwide energy savings and reduction of greenhouse gas emissions are discussed. A recent effort in achieving a saturation induction beyond 1.65 T in nanocrystalline alloys is mentioned.

International Nuclear Information System (INIS)

Argon ions irradiation of 12% Cr steels and Fe/Cr alloys results in the hardening up to 10000 MPa. This value exceeds the hardening level even for martensitic transformation. Along with the increase of microhardness following irradiation the shape of X-ray graph of the affected materials changes considerable. Hardening value and behavior are determined by temperature radiation doze, preliminary ageing, extent of cold strain and alloying. The odserved phenomenon is supposed to be caused by irradiation-induced structural transformations. Reversibility of radiation hardening of the materials in question was observed.

International Nuclear Information System (INIS)

Semiconductor properties of passive films formed on the Fe-18Cr alloy in a borate buffer solution (pH = 8.4) and 0.1 M H_2SO_4 solution were examined using a photoelectrochemical spectroscopy and an electrochemical impedance spectroscopy. Photo current reveals two photo action spectra that derived from outer hydroxide and inner oxide layers. A typical n-type semiconductor behaviour is observed by both photo current and impedance for the passive films formed in the borate buffer solution. On the other hand, a negative photo current generated, the absolute value of which decreased as applied potential increased in the sulfuric acid solution. This indicates that the passive film behaves as a p-type semiconductor. However, Mott-Schottky plot revealed the typical n-type semiconductor property. It is concluded that the passive film on the Fe-18Cr alloy formed in the borate buffer solution is composed of both ...

Energy Technology Data Exchange (ETDEWEB)

Metal dusting corrosion has been a serious problem in the petroleum and petrochemical industries, such as reforming and syngas production systems. This form of deterioration has led to worldwide material loss for 50 years. For the past three years, we have studied the mechanism of metal dusting for Fe- and Ni-base alloys. In this report, we present a correlation between the weight loss and depth of pits that form in Ni-base alloys. Nickel-base alloys were also tested at 1 and 14.8 atm (210 psi), in a high carbon activity environment. Higher system pressure was found to accelerate corrosion in most Ni-base alloys. To reduce testing time, a pre-pitting method was developed. Mechanical scratches on the alloy surface led to fast metal dusting corrosion. We have also developed preliminary data on the performance of weldments of several Ni-base ...

Energy Technology Data Exchange (ETDEWEB)

The compositions of passive films formed on Fe-17Fr-13Ni (at. %) and Fe-18.5Cr-14Ni-1.5Mo (100) single crystals have been determined and the structure of the alloy under the film has been investigated. The alloys were passivated in 0.05M H{sub 2}SO{sub 4} at 250 mV/SHE for 30 min. The oxygen content was measured by nuclear microanalysis using the {sup 16}O(d,p) {sup 17}O* reaction. The oxygen content in the passive film is similar for the two alloys and equal to (12{plus minus}2) 10{sup 15} O/cm{sup 2}. The cationic compositions of the passive films have been determined by {sup 4}He channeling at two incident beam energies: 0.8 and 2.0 MeV. For the two alloys studied, a total cation content of (5{plus minus}2)10{sup 15} at/cm{sup 2} is found in the passive films. The corresponding thickness is about 12 A. There is an excess of oxygen, which can be attributed to ...

International Nuclear Information System (INIS)

The microstructures of so called high temperature alloys, which have been developed for service temperatures up to 800"0C, are not necessarily stable at higher temperatures. The mobility of alloying elements is very high in FeCrNi alloys at 950 "0C e.g. iron, chromium or nickel can diffuse up to 0.1 mm distance in one year, which is about a grain diameter. Interstitials like carbon or nitrogen show a four orders of magnitude higher diffusivity than the alloying elements. In addition, the carbon solubility in this type of alloy is reported to be very low. Therefore the alloys are supersaturated with carbon after heat treatment above 1100 "0C and water quenching although the absolute carbon content is very low. At service temperatures around 800"0C the solubility of carbon is still about one order of magnitude lower than at heat treatment ...

British Library Electronic Table of Contents (United Kingdom)

Thermal (gas) nitridation of stainless steel alloys can yield low interfacial contact resistance (ICR), electrically conductive and corrosion-resistant nitride containing surface layers (Cr2N, CrN, TiN, V2N, VN, etc.) of interest for fuel cells, batteries, and sensors. This paper presents results of proton exchange membrane (PEM) single-cell fuel cell studies of stamped and pre-oxidized/nitrided developmental Fe-20Cr-4V weight percent (wt.%) and commercial type 2205 stainless steel alloy foils. The single-cell fuel cell behavior of the stamped and pre-oxidized/nitrided material was compared to as-stamped (no surface treatment) 904L, 2205, and Fe-20Cr-4V stainless steel alloy foils and machined graphite of similar flow field design. The best fuel cell behavior among the alloys was exhibited...

International Nuclear Information System (INIS)

Three ternary austenitic alloys (Fe-15Cr-25Ni, Fe-15Cr-25Ni-0.04P, Fe-15Cr-45Ni in both annealed and cold worked conditions) were irradiated at 465 C to 0.15, 0.28, and 0.42 dpa at above core position in the Fast Flux Test Facility utilizing the Materials Open Test Assembly to study the separate and synergistic effects of He/dpa ratio, phosphorus addition, nickel content and cold work level on microstructural evolution and hardening. The helium/dpa ratio was varied by isotopic doping with "5"9Ni to enhance the production rate of helium. The helium production rate was evaluated to be 62 appm He/dpa in the "5"9Ni-doped specimens and 0.26 appm He/dpa in the undoped specimens. Transmission electron microscopic examinations revealed that alloy composition affected significantly the evolution of microstructure during irradiation. Phosphorus addition prevented the formation of Frank loops ...

International Nuclear Information System (INIS)

Repassivation behavior and IGA resistance of nickel base alloys containing 0#approx#30 wt% chromium was investigated in high temperature acid sulfate solution. (1) The repassivation rate was increased with increasing chromium content. And so the amounts of charge caused by the metal dissolution were decreased with increasing chromium content. (2) Mill-annealed Alloy 600 suffered IGA at low pH environment below about 3.5 at the fixed potentials above the corrosion potential in 10%Na_2SO_4+H_2SO_4 solution at 598K. On the other hand, thermally-treated Alloy 690 was hard to occur IGA at low pH environments which mill-annealed Alloy 600 occurred IGA. (3) It was considered that the reason, why nickel base alloys containing high chromium content such as Alloy 690 (60%Ni-30%Cr-10%Fe) had high IGA/SCC resistance in high temperature acidic solution ...

Energy Technology Data Exchange (ETDEWEB)

Secondary ion mass spectrometry (SIMS) has been used to investigate changes that occur in an advanced Ir-0.3W alloy during high temperature aging. This alloy is used to clad /sup 238/PuO/sub 2/ heat sources used in thermoelectric generators for deep space reconnaissance satellites. Long-term direct contact with PuO/sub 2/ at 1400/sup 0/C leads to physical and chemical changes within the cladding alloy that affect its metallurgical properties. SIMS was used to show that Cr, Fe, Ni, and in some cases O, diffuse from the PuO/sub 2/ into the alloy. Thorium and aluminum diffuse out of the alloy in these same regions. This SIMS study suggests that inward O diffusion and subsequent formation of ThO/sub 2/ on grain boundaries may stabilize the alloy against enhanced grain growth.

Energy Technology Data Exchange (ETDEWEB)

Stress corrosion cracking tests in constant extension rate tensile (CERT) and constant load tensile (CLT) tests were conducted on Ni-xCr- 9Fe-yC in Ar, water, and a LiOH-boric acid solution. Cr and C improve the resistance of Ni-base alloys to IG cracking in both Ar and water at 360C. Since creep plays a role in IG cracking, one possible explanation for the role of the environment involves its effect on the creep. Experiments were conducted on the role of C in the deformation behavior and failure mode of Ni-16Cr-9Fe. Constant load experiments were conducted on Ni-16Cr-9Fe to determine if the CLT test is more aggressive than CERT. The electron backscattering technique in a SEM is being developed in order to extend the IG cracking studies to grain sizes typical of commercial alloys, 20-30 microns.

Energy Technology Data Exchange (ETDEWEB)

The morphology and size characteristics of the population of AlP particles produced by treatment of a pure aluminium melt with an Al-Fe-P inoculant addition have been determined. The particles are shown to be polyhedral like the primary silicon they nucleate in hypereutectic Al-Si alloy melts and to be prone to clustering at increased phosphorus addition levels. The number of AlP particles per unit area is shown to be comparable with the corresponding number density of polyhedral primary silicon in Al-20 wt.% Si treated in the same way under identical conditions which is consistent with earlier conclusions that AlP acts as a nucleation catalyst for primary silicon in hypereutectic Al-Si casting alloys. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Passive films formed on Alloy 690 in different pH solutions at high temperatures were studied by potentiodynamic polarization, Auger electron spectroscopy, thermodynamic diagrams and the Mott-Schottky relation. The chemical compositions and electronic structures of the passive films were found to be strongly pH-dependent. In alkaline solutions, a secondary passivation was clearly observed on potentiodynamic polarization curves. The passive films were a mixture of Cr{sub 2}O{sub 3} and FeCr{sub 2}O{sub 4} below the flat band potential of nickel oxide and were NiFe{sub 2}O{sub 4} above this potential. Electronic structure models, describing the electrochemical properties of the passive films, are proposed and discussed.

Energy Technology Data Exchange (ETDEWEB)

The ball-milling method was used to produce Mg-50 wt.% ZrFe{sub 1.4}Cr{sub 0.6} composite. The thermodynamic, kinetic, and cycling properties, as well as the resistance to oxidation were examined. This composite possesses excellent kinetic properties, even at moderate temperature. Scanning electron microscopy, energy-dispersive spectrum, transmission electron microscopy and X-ray diffraction were used to characterize the composite before and after hydriding. The fine ZrFe{sub 1.4}Cr{sub 0.6} particles covering Mg particles acting as a ''catalytic film'', a significant amount of imperfections and some alloy powder in the Mg matrix introduced by ball milling all contributed to the enhanced absorption/desorption rate. (orig.)

International Nuclear Information System (INIS)

Strain rate effects for the high strength, metastable beta-titanium alloy Ti-8Mo-8V-2Fe-3Al are assessed in terms of tensile and fracture toughness behavior. It is shown that as the strain rate increases the yield strength, ultimate tensile strength, and ductility also increase. As a result of the decrease in the amount of intergranular fracture as the strain rate is increased, the dynamic fracture toughness values K/sub Id/ are greater than those obtained under static conditions as given by K/sub Q/.

Science.gov (United States)

The papers contained in this volume provide an overview of recent theoretical and experimental research related to the fracture toughness and fatigue crack growth characteristics of titanium alloys. Topics discussed include room temperature fatigue crack propagation in beta-titanium alloys, fatigue crack growth rate acceleration in alpha+beta Ti alloys, influence of transformed beta microstructures on fatigue crack growth rates in Ti-6Al-4V, and the role of inclusion and pore content on the fracture toughness of powder processed blended elemental Ti-10V-2Fe-3Al. Papers are also presented on fatigue crack growth measurements in an alpha-beta titanium alloy, the effects of thermal processing variation on the properties of Ti-6Al-4V, and the effect of microstructure on ductility and fracture toughness of alpha+beta titanium alloys.

International Nuclear Information System (INIS)

In this study the results of mathematical simulation and experimental research of texture transition in stress assisted shear phase transformations are discussed. The orientation distribution function (ODF) calculation model to the any type crystalline lattice symmetry materials has been suggested. By crystalline lattice symmetry analysis this computer program determines necessary amount of the initial experimental data. The experimental verification supports this model well. The ODF calculation model after shear phase transformation with equal use of all possible variants of orientation relationship or with various degrees of variant selection worked out. In this study the experimental and calculating data of the direct and reversal shear transformations #alpha# <=> #gamma# in Fe-alloys and B2 <=> B19' in Ti-Ni alloys are discussed. The stress assisted shear phase transformation model and computer program to calculate ODF after ...

International Nuclear Information System (INIS)

Corrosion tests of titanium alloys VTI-0, OT4, VT5-1 and steel Kh18N1OT in 10% and 18% HCl with additions of carnallite at 40 deg C have been carried out. It has been established that titanium alloys in 10% and 18% HCl containing 5 and 10% carnallite are sufficiently corrosion resistant in the presence of 0.1-1% FeCl or HNO_3 and can be used for manufacturing the equipment of recirculation gas scrubbers. Steel Kh18N10T is unstable in all the media tested. It is subjected to intensive pitting. Specimens of steel Kh18N10T have also revealed edge cracking.

British Library Electronic Table of Contents (United Kingdom)

Nitridation of Cr-bearing alloys can yield low interfacial contact resistance (ICR), electrically conductive and corrosion-resistant CrN or Cr2N base surfaces of interest for a range of electrochemical devices, including fuel cells, batteries, and sensors. This paper presents results of exploratory studies of the nitridation of commercially available, high Cr (30-35wt%) Ni-Cr alloys and a ferritic high Cr (29wt%) stainless steel for proton exchange membrane fuel cell (PEMFC) bipolar plates. A high degree of corrosion resistance in sulfuric acid solutions designed to simulate bipolar plate conditions and low ICR values were achieved. Oxygen impurities in the nitriding environment were observed to play a significant role in the nitrided surface structures that formed, with detrimental effect...

International Nuclear Information System (INIS)

Passive films formed on Alloy 690 in high-temperature alkaline environments were investigated by potentiodynamic polarization, X-ray photoelectron spectroscopy, transmission electron microscopy and Mott-Schottky approach. Passive current density and donor density of the passive films increase with increasing temperature, due to increased diffusion rates of metallic ions and dehydration of hydroxide phases. The passive films show a duplex structure including an inner layer of fine-grained Cr oxide or spinel oxide and an outer layer of Ni-Fe spinel oxide and Ni hydroxide. A growth model of the passive films on Alloy 690 in high-temperature alkaline environments is proposed and discussed.

International Nuclear Information System (INIS)

The effect of Mo addition as an alloying element to stainless steel alloys is investigated by capacitance (Mott Schottky approach), and photoelectrochemistry measurements. Complementary studies were made using Auger electron spectroscopy and X-ray photoelectron spectroscopy. The Mott-Schottky approach and the photoelectrochemical studies showed that the presence of Mo as an alloying element affects the semiconductive properties of the oxide films. The analytical results have shown that the oxide films formed on stainless steels are composed by an external Fe rich region and an inner Cr rich region. No significant amount of Mo was found in the outer layers of the film. The presence of Mo leads to an increase of the chromium content in the inner layers of the film, although without increasing the film thickness. (orig.)

International Nuclear Information System (INIS)

Austenitic stainless steels (304-type) have been implanted with nitrogen ions in order to investigate the effects of implanted nitrogen on their electrochemical behaviour and on the nature of the passive film formed on the steels in acid (0.5M H_2SO_4). Alloys with two nitrogen doses have been prepared (2.5x10"1"6 and 2x10"1"7 N atoms/cm"2). The implanted alloys have been characterized by "1"5N-NRA (nuclear reaction analysis) and XPS (X-ray photoelectron spectroscopy). Alloy surfaces with well-defined N concentrations were prepared, prior to the electrochemical measurements, by argon-ion sputtering of the implanted material for a fixed time in order to reach a well-defined point on the nitrogen depth profile. The samples were then transferred without exposure to air to an electrochemical cell mounted in an inert gas glove box. The implanted nitrogen modifies the electrochemical behaviour of the alloy. ...

Energy Technology Data Exchange (ETDEWEB)

Manganese-iron base and manganese-chromium-iron base austenitic alloys designed to have resistance to neutron irradiation induced swelling and low activation have the following compositions (in weight percent): 20 to 40 Mn; up to about 15 Cr; about 0.4 to about 3.0 Si; an austenite stabilizing element selected from C and N, alone or in combination with each other, and in an amount effective to substantially stabilize the austenite phase, but less than about 0.7 C, and less than about 0.3 N; up to about 2.5 V; up to about 0.1 P; up to about 0.01 B; up to about 3.0 Al; up to about 0.5 Ni; up to about 2.0 W; up to about 1.0 Ti; up to about 1.0 Ta; and with the remainder of the alloy being essentially iron.

Energy Technology Data Exchange (ETDEWEB)

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 ...

Energy Technology Data Exchange (ETDEWEB)

Nitridation of Cr-bearing alloys can yield low interfacial contact resistance (ICR), electrically conductive and corrosion-resistant CrN or Cr{sub 2}N base surfaces of interest for a range of electrochemical devices, including fuel cells, batteries, and sensors. This paper presents results of exploratory studies of the nitridation of commercially available, high Cr (30-35 wt%) Ni-Cr alloys and a ferritic high Cr (29 wt%) stainless steel for proton exchange membrane fuel cell (PEMFC) bipolar plates. A high degree of corrosion resistance in sulfuric acid solutions designed to simulate bipolar plate conditions and low ICR values were achieved. Oxygen impurities in the nitriding environment were observed to play a significant role in the nitrided surface structures that formed, with detrimental effects for the Ni-Cr base alloys, but beneficial effects for the stainless steel alloy. Positive results from ...

British Library Electronic Table of Contents (United Kingdom)

The alloying effects on K to L shell vacancy transfer probabilities (?KL) in 3d transition metals have been carried out by X-ray fluorescence studies of various alloy compositions. K X-ray intensity ratios of Ti, Cr, Fe, Co, Ni, and Cu elements in the FexNi1?x, FexCr1?x, NixCr1?x, FexCryNi1?(x+y), TixNi1?x, TixCo1?x, and CoxCu1?x alloys have been measured following excitation by 22.69keV X-rays from a 10 mCi 109Cd radioactive point source and ?KL values for alloying elements have been determined from these ratios. The spectrum of characteristic K-X-ray photons from samples were detected with a high resolution Si(Li) detector coupled to a 4 K multichannel analyzer. The present investigation makes it possible to ...

Energy Technology Data Exchange (ETDEWEB)

Fe-Ni-Mn martensitic steels are one of the major groups of ultra-high strength steels that have good mechanical properties and ductility in as annealed condition but they suffer from severe inter-granular embitterment after aging. In this paper, the effect of heavy shaped cold rolling and wire drawing on the mechanical properties of Fe-Ni-Mn steel was investigated. This process could provide a large strain deformation in this alloy. The total strain was {epsilon} {approx}7. Aging behavior and tensile properties of Fe-10Ni-7Mn were studied after aging at 753 K. The results showed that the ultimate tensile strength and ductility after cold rolling, wire drawing and aging increased up to 2540 MPa and 7.1 %, respectively, while the conventional steels show a premature fracture stress of 830 MPa with about zero ductility after aging.

Energy Technology Data Exchange (ETDEWEB)

Low-cost titanium alloy components are getting increasing attention in aerospace applications. Cost reductions are possible in the alloys themselves and in the production techniques. The former aspect is less promising as titanium alloys are costly to produce. Of course, there are some new developments like the (alpha plus beta) alloy Ti-6 Al-2 Fe-0.2 Si (TIMETAL 62S) and the beta-alloy Ti-6.8 Mo-4.5 Fe-1.5 Al (TIMETAL LCB), in which low-cost iron replaces costly beta alloying elements like vanadium or molybdenum, but these will be used mainly on the mass production markets, e.g. motor car construction. In consequence, optimisation of production methods is the more promising option. Near net shape processes will reduce the production cost and improve the fly-to-buy ratio. Some of these production processes are explained. ...

Energy Technology Data Exchange (ETDEWEB)

Anisotropic Nd{endash}Fe{endash}B magnet powders can be produced by the hydrogenationdecomposition-desorption-recombination (HDDR) process from Nd{endash}Fe@ xnB{endash}Co{endash}M ({ital M}=Ga, Zr, Nb, Hf, and Ta) alloys. The present status of those HDDR powders and the bonded magnets made from them are reviewed with regards to the powder particle size dependence of their magnetic properties, their magnetic thermal stability, and their magnetization behavior. The results of a mechanistic study on the recombination step are also presented. The magnetic properties of the anisotropic HDDR powder depend relatively little on the powder particle size. Bonded magnets with a density of {approximately}6.20 g/cm{sup 3} and a BH{sub max} of 18.5{endash}20.5 MGOe can be produced from anisotropic HDDR powders with particle sizes of below 300 {mu}m diam. The temperature coefficient of the intrinsic coercive force {sub {ital iH}}{sub ...

Energy Technology Data Exchange (ETDEWEB)

Positron annihilation experiments on Fe-Cu model dilute alloys of nuclear reactor pressure vessel (RPV) steels have been performed after neutron irradiation in JMTR. Nanovoids whose inner surfaces were covered by Cu atoms were clearly observed. The nanovoids transformed to ultrafine Cu precipitates by dissociating their vacancies after annealing at around 400degC. The nanovoids and the ultrafine Cu precipitates are strongly suggested to be responsible for irradiation-induced embrittlement of RPV steels. Effects of Ni, Mn and P addition on the nanovoid and Cu precipitate formations were also studied. The nanovoid formation was enhanced by Ni and P, but suppressed by Mn. The Cu precipitates after annealing around 400degC were almost free from these doping elements and hence were pure Cu in the chemical composition. Furthermore the Fermi surface of the 'embedded' Cu precipitates with a body centered cubic crystal structure was ...

International Nuclear Information System (INIS)

The Self Actuated Shutdown System (SASS) is now under development for use in a large scale FBR, in order to establish the passive shutdown capability against the postulated ATWS events, i.e. ULOF, UTOP and ULOHS. The function of SASS makes use of the safety characteristics of a liquid metal cooled FBRs such as a large subcooling and low pressure system. The insertion of the control rods insertion is assured even in the most conservative seismic design condition by employing articulate rods and the SASS will be installed into the detaching mechanism employing a curie point the magnet alloy. ULOF analysis of the present FBR shows that coolant boiling inception is prevented if a control rod of the SASS is detached at the uppermost temperature of 680degC for the Curie point magnet, and after the reactor shutdown the coolant temperature is kept below 600degC by the pony motor flow. Therefore the SASS will establish passive shutdown capability without affecting the core ...

International Nuclear Information System (INIS)

Heusler films with L2_1 and B2 structure are deposited simultaneously on amorphous carbon films, Si(100) surfaces, and in situ cleaved InAs(110) surfaces by coevaporation of Ni and the alloy MnIn. Morphology, structure, and stoichiometry are investigated with transmission-electron microscopy, electron diffraction, and X-ray spectroscopy. The almost perfect lattice match supports highly oriented growth of Ni_2MnIn on InAs, which is proven by electron diffraction under grazing incidence. The electrical resistivity of thin films on Si show metallic behavior. At temperatures of liquid helium point-contact Andreev reflection spectroscopy is performed on films grown on Si(100) and in situ cleaved InAs(110) surfaces yielding spin polarizations comparable to the ones of Fe, Ni, Co, and permalloy (Ni_8_0Fe_2_0).

British Library Electronic Table of Contents (United Kingdom)

Magnetic properties of Fe-Co-Mo-Cu-B alloy system with Co up to 26at.% were investigated. After proper thermal treatment, the nanocrystalline grain remains tiny, the density hardly increases, but the room-temperature saturation attains 1.5T mainly due to a high enough Curie temperature. The generally observed slant hysteresis loops point to ribbon surfaces, which stress the ribbon interior and induce a specific magnetoelastic contribution to hard-ribbon-axis magnetic anisotropy even after vacuum annealing. The effect does not come from cobalt but rather from the lack of silicon. Partial removal of the surfaces resulted in a decrease of the loop tilt.

International Nuclear Information System (INIS)

The effects of alloying elements and precipitated phases on the corrosion rate of high alloy OCTG in the ferric chloride solution have been evaluated. The corrosion rate of Fe-Cr-Ni-Mo alloys without precipitated phases, e.g. carbides and sigma phase, can be estimated from the composition using the following equation: log(C.R.)=-0.144xPRE-7690/(273+T)+28.6 where C.R. is the corrosion rate in g/m/sup 2//hr; PRE is Cr+3Mo+16N in percent and T is the test temperature in "0C. The activation energies of the ferric chloride test are almost the same regardless of PRE or Ni content when no detrimental phase precipitates. When carbides or the sigma phase precipitate, the corrosion rate is higher and the activation energy is lowered. This suggests that secondary phases give preferential sites for initiation of pitting corrosion.

International Nuclear Information System (INIS)

A dilute tungsten heavy alloy consisting of 50W-35Ni-15Fe (wt pct) was liquid phase sintered at 1,500 C for times ranging from 30 to 960 minutes. This alloy corresponds to a nominal solid content of 20 vol pct at the sintering temperature. Because of the excess liquid, the alloy densified easily and exhibited extensive liquid-solid separation due to the density difference between the phases. The solid content at the compact bottom ranged from 45 to 70 vol pct over position and time. The microstructure of the settled region was quantified for volume fraction of tungsten, grain size, connectivity, and settled solid angle of repose. These results provide a basis for extending the microstructural parameters to possible microgravity conditions. The grain growth rate constant varies with the inverse 2/3 power of the volume fraction of liquid, possibly reflecting combined coalescence and ...

International Nuclear Information System (INIS)

The main compositions of iron-base amorphous self-fluxing alloy powders of 150 mesh, used in this work, are Fe, Cr, Ni, W, Mo, B, Si and C. The ranges of each element in at% are (65-70)Fe, (3-5)Cr, (2-4)Ni, (2-4)W, (1-2)Mo, (10-14)B, (4-7)Si and (2-3)C. The atomic ratio of metal-metalloid is about 80:20, so this alloy is abbreviated as M_8_0X_2_0. The material on which coatings were deposited is 1020 steel, austenitized for 1h at 880 C, water quenched, and tempered at 180 C for 1h. This heat treatment resulted in a low carbon martensite structure with a hardness of HRC35-45. After cleaning, shot blasting and preheating the steel to about 200 C, the authors sprayed a thin Ni-Al alloy layer of about 0.1--0.15mm in thickness onto the specimen by means of an oxygen-acetylene torch to provide better bonding of the coating with substrate. Then the M_8_0X_2_0 and M_8_0X_2_0+8%CeO_2 ...

International Nuclear Information System (INIS)

The hardening and embrittlement of reactor pressure vessel (RPV) steels is of great concern in the actual nuclear power plant life assessment. This embrittlement is caused by irradiation-induced damage, like vacancies, interstitials, solutes and their clusters. The current procedure to estimate material properties for the irradiated pressure vessels is based on Charpy-V tests of identical material located at the inner shell of the reactor. But the reason for the embrittlement of the materials is not yet totally known. The real nature of the irradiation damage should thus be examined as well as its evolution in time. Fe-Cu binary alloys are often used to mimic the behaviour of such steels. Their study allows. Identifying some of the defects responsible of the hardening, especially when compared to pure iron or C-micro-alloyed iron. More recently the influence of manganese and nickel in low-Cu RPV steels has become a ...

International Nuclear Information System (INIS)

Ti-10V-2Fe-3Al is high strength, metastable beta titanium alloy developed by the Timet Division, Titanium Metals Corporation of America for enhanced forgeability and excellent mechanical property combinations, including deep hardening characteristics. Ti-10-2-3 has been the subject of intense thermomechanical processing (TMP) development and reduction to commercial practice for the full range of open die, closed-die and precision forged products utilized in aerospace and other applications. With commercially proven TMP, Ti-10-2-3 forgings provide a range of strength-fracture toughness combinations from 180 Ksi (1,240 MPa) minimum U.T.S. to 140 Ksi (965 MPa) minimum U.T.S with commensurate fracture toughness. With optimal TMP and these strength-toughness combinations, Ti-10-2-3 forgings are found provide superior smooth and notched fatigue properties critical to aerospace applications over incumbent alpha-beta alloys. The ...

International Nuclear Information System (INIS)

Microstructure characterization is important for controlling the quality of laser welding. In the present work, a detailed microstructure characterization by transmission electron microscopy was carried out on the laser welding cast Ni-based superalloy K418 turbo disk and alloy steel 42CrMo shaft and an unambiguous identification of phases in the weldment was accomplished. It was found that there are #gamma#-FeCrNiC austenite solid solution dendrites as the matrix, (Nb, Ti) C type MC carbides, fine and dispersed Ni_3 Al #gamma#' phase as well as Laves particles in the interdendritic region of the seam zone. A brief discussion was given for their existence based on both kinetic and thermodynamic principles.

Energy Technology Data Exchange (ETDEWEB)

Passive films were formed on a high purity Fe-23 Cr alloy in acid sulfate solutions in the presence and absence of chloride ion. The resulting film composition was investigated by Auger depth profiling. The passivated samples were exposed to a 1M NaCl solution at a constant potential slightly above the critical pitting potential, and the current-time transient was measured in order to compare the relative stability of the different films. The results obtained suggest that the formation conditions influence the chloride content of the passive film and the breakdown behavior. Passive films formed in the presence of chloride contain and are slightly less stable towards breakdown. No chloride was found in films formed in sulfate and subsequently exposed to chloride well below the pitting potential.

International Nuclear Information System (INIS)

The results of a combined investigation of splat-quenched Fe-Csub(x) (x<0.05) alloys by resistivity, X-ray diffraction and Moessbauer spectroscopy are presented. The residual resistivity increases linearly with the carbon content (#DELTA#rho=5#mu##OMEGA#cm/at.%) with a slope identical to that observed in the dilute ferritic phase. X-ray diffraction reveals the presence of a martensite structure in addition to a small fraction of residual austenite; the dependence of the a and c lattice parameters on xsub(c) agrees with earlier measurements. A detailed investigation of the relative reflexion intensities shows that the as-quenched martensites consist of a mixing of massive martensite and tetragonal martensite for low carbon content and of tetragonal martensite only for xsub(c) approximately 0.05. The Moessbauer spectra reveal 3 or 4 magnetically non equivalent iron sites. From a detailed analysis of the intensity dependence of the subspectra ...

International Nuclear Information System (INIS)

The effect of mean stress, or the stress ratio (R), on the fatigue-crack growth (FCG) behavior of #alpha#-aged and #omega#-aged microstructures of the beta titanium alloy Ti-10V-2Fe-3Al was investigated. While the mean stress had a negligible effect on the FCG behavior of the #alpha#-aged microstructure, a strong effect was observed in the #omega#-aged microstructure. In particular, the values of the threshold stress-intensity range (#DELTA#K_t_h) exhibited a strong dependence on R in the #omega#-aged microstructure, while this dependence was weak in the #alpha#-aged microstructure. These effects seem to arise primarily from fracture-surface roughness-induced crack closure. The crack closure levels for the #alpha#-aged microstructure were found to be very low compared to those for the #omega#-aged microstructure. Transmission electron microscopy and scanning electron microscopy studies of microstructures and fracture surfaces were performed to ...

International Nuclear Information System (INIS)

In this work, the Calibration-Free approach for Laser-Induced Breakdown Spectroscopy (CF-LIBS) was applied for the first time to radially resolved spectra emitted by a laser-induced plasma. The radial profiles of plasma temperature and electron number density were used to calculate the local relative concentration of the elements of interest. We analyzed a set of profiles of the local spectral emission coefficient obtained previously by means of spatial deconvolution of the spectra from a copper-based alloy (Cu 93, Fe 5, Mn 1, Ni 1 wt.%) laser-induced plasma. A spatially integrated spectrum of the same plasma was also analyzed for comparison purpose. The relative abundance of the minor components Fe, Mn and Ni was calculated. The results obtained from the central region of the plasma were closer to the nominal concentrations than those obtained from the spatially integrated spectrum. However, an increasing deviation was ...

International Nuclear Information System (INIS)

FexZn1-x alloys were electrochemically deposited on aluminum substrates from a sulfate bath. The K?/K? x-ray intensity ratios of Zn and Fe in FexZn1-x thin films have been experimentally studied. The energy dispersive x-ray fluorescence (EDXRF) technique was used to measure K x-ray photons. Samples were excited by using 59.5 keV photons emitted by a 50 mCi 241Am radioactive source. The emitted K x-rays were detected by an Ultra-LEGe detector having a resolution of 150 eV at 5.9 keV. In addition, the effect of bath composition on the phase structure was investigated by x-ray diffraction (XRD) analysis. The composition of the thin films was analyzed by atomic absorption spectrometry analysis. Iron content was shown to strongly affect the structure of Zn-Fe alloys. It was found that the K-shell x-ray intensity ratio changed in FexZn1-x thin films for different values of x. The reason for this change may be ...

Energy Technology Data Exchange (ETDEWEB)

Thermal (gas) nitridation of stainless steels can yield low interfacial contact resistance (ICR), electrically-conductive and corrosion-resistant nitride containing surfaces (Cr2N, CrN, TiN, V2N, VN, etc) of interest for fuel cells, batteries, and sensors. This paper presents the results of scale up studies to determine the feasibility of extending the nitridation approach to thin 0.1 mm stainless steel alloy foils for proton exchange membrane fuel cell (PEMFC) bipolar plates. A major emphasis was placed on selection of alloy foil composition and nitidation conditions potentially capable of meeting the stringent cost goals for automotive PEMFC applications. Developmental Fe-20Cr-4V alloy and type 2205 stainless steel foils were treated by pre-oxidation and nitridation to form low-ICR, corrosion-resistant surfaces. Promising behavior was observed under simulated aggressive anode- and cathode- side ...

International Nuclear Information System (INIS)

The nanocrystallization process of amorphous Fe_7_3_._5Si_1_3_._5B_9Nb_3Cu_1 was investigated by active screen plasma nitriding (ASPN) treatment at temperatures ranging from 410 "oC to 560 "oC for 3 h in two gas mixtures of 75% N_2-25% H_2 and 25% N_2-75% H_2 at 5 mbar atmosphere. The amorphous ribbons were then annealed under vacuum at the same time and temperatures mentioned above. The structure of the samples was analyzed using various techniques such as X-ray diffraction (XRD), atomic force microscopy (AFM) and differential scanning calorimetry (DSC). Microhardness measurements, electrical resistivity and Vibrating Sample Magnetometer (VSM) were used to study mechanical, electrical and magnetic properties of the samples, respectively. It was observed that the ASPN treatment leads to finer grain size and higher crystalline volume fraction and modifies the structural features of Fe(Si) phase. The Fe(Si) lattice parameter ...

Energy Technology Data Exchange (ETDEWEB)

Results are presented from studies on the quality of cast parts made by counterpressure casting of high-strength aluminum alloy AMKh-605, and Al-Cu-Mn-Cr alloys (5.6-6.4% Cu, 0.25-0.55% Mn, 0.20-0.55% Cr, 0.20-0.45% Ti, 0.08-0.25% Zr, less than or equal to0.25% Fe, less than or equal to0.25% Si, less than or equal to0.05% Mg). Chill castings were heat treated by quenching from 450/sup 0/C (20 hours) in water, aging at 160/sup 0/C for five hours with cooling in air. Fractograms of tensile specimens are presented. Scanning electron microscopy allows an ambiguous determination of the cause of failure of a part, be it at initial crystallization crack defects or burns, and also allows a relationship to be established between structure and mechanical properties.

International Nuclear Information System (INIS)

Measurements of the magnetic susceptibility betweeen 0.03 and 300 K and of the magnetization between 0.05 and 10 K for magnetic fields up to 60kOe have been used to investigate effects from the interaction between the conduction electrons and local magnetic moments in (Lasub(1-x)Cesub(x))B_6 alloys (0.0007<=x<=0.10). For Ce concentrations x<0.006 the data show Kondo-type single impurity behaviour at low temperatures with a transition from a magnetic to a non-magnetic regime of the Ce ions. In the magnetic regime the impurity susceptibility follows a Curie-Weiss law, and in the non-magnetic regime it varies with T"2. An external magnetic field gradually restores the free-ion behaviour of the Ce impurities. For more concentrated alloys interactions between the impurities are observed. The RKKY interaction strength derived is more than two orders of magnitude smaller than in the Kondo system CuFe. Values of the s-f ...

Energy Technology Data Exchange (ETDEWEB)

This report presents the results of cladding technology development under the Coal-Fired Combined Cycle DOE Project for the period July 1976 through June 1978. Sub-task 3.1, Clad Alloy Development, involved the selection, fabrication and burner rig evaluation of advanced clad alloy compositions diffusion-bonded to IN-738. Testing was conducted for up to 5800 hours at 1600/sup 0/F in a simulated PFB environment. Metallographic evaluation showed Co-base cladding alloys PFB-5PM and PFB-6PM (aluminided) and Fe-base alloy GE-2541 to be the most corrosion resistant. The formability and fabricability of sheet material was significantly improved for these alloys by utilizing powder metallurgy techniques. Sub-task 3.2, Clad Process Development, encompassed processing activities to evaluate sheet alloy formability, bucket surface preparation ...

International Nuclear Information System (INIS)

Mechanical testing of controlled-purity Ni-xCr-9Fe-yC alloys at 360 C revealed an environmental enhancement in IG cracking and time-dependent deformation in high purity and primary water over that exhibited in argon. Dimples on the IG facets indicate a creep void nucleation and growth failure mode. IG cracking was primarily located at the interior of the specimen and not necessarily linked to direct contact with the environment. Controlled potential CERT experiments showed increases in IG cracking as the applied potential decreased, suggesting that hydrogen is detrimental to the mechanical properties. It is proposed that the environment, through the presence of hydrogen, enhances IG cracking by enhancing the matrix dislocation mobility. This is based on observations that dislocation-controlled creep controls the IG cracking of controlled-purity Ni-xCr-9Fe-yC in argon at 360 C and grain boundary cavitation and sliding ...

International Nuclear Information System (INIS)

Focused ion beam (FIB) microscopes have become well-established in the semiconductor industry during the past decade, and are rapidly gaining attention in the field of materials science, both as a tool for producing site specific, parallel sided transmission electron microscope (TEM) specimens and as stand alone specimen preparation and imaging systems. FIB secondary electron imaging (SEI) of nickel-based alloys, such as commercially produced Alloy 600 (approximately Ni 15Cr 10Fe 0.5C), has been demonstrated to show a high degree of sensitivity to the presence of deformation in the alloy, and FIB secondary ion imaging (SII) is particularly useful for identifying the presence of grain boundary corrosion, as secondary ion yields from metallic specimens can increase by three orders of magnitude in the presence of oxygen. This 'oxygen enhanced yield', makes FIB SII ideal for detection of corrosion at grain ...

Energy Technology Data Exchange (ETDEWEB)

The Recycler ring magnet will be made of Strontium ferrite permanent magnets. A strontium ferrite permanent magnet without compensation has a temperature coefficient of -0.2 % in dB/dT. To compensate this effect, we are utilizing 30 % Ni 70 % Fe alloy, a temperature compensation ferromagnetic material with a low Curie point. To search for optimum commercially available material and optimum condition, we made a couple of simple model magnets, and tested with several different compensating material. The test results are reported and its optimal conditions are shown. Several different configurations were tested including a possible 2 kG magnet configuration.

Energy Technology Data Exchange (ETDEWEB)

Chemical characterization of passive films formed on AISI 304 austenitic stainless steel, in a borate/boric acid solution at pH 9.2, under various conditions of potential, temperature, and polarizations time, was made by Auger electron spectroscopy combined with ion sputtering, and x-ray photoelectron spectroscopy (XPS). The depth chemical composition, thickness, and duplex character of the passive layers were determined after processing AES sputter profiles by their quantitative approach based on the sequential layer sputtering model. Moreover, separated contributions of elements in their oxidized and unoxidized state could be disclosed from part to part of the oxide-alloy interface. The XPS study specified the chemical bondings which take placed inside the film, between Fe and oxygen (and water).

International Nuclear Information System (INIS)

Separate effect of impurities and alloying additions of phosphorus, silicon, boron, carbon, sulphur, magnesium, copper, aluminium and molybdenum on the tendency to intergranular corrosion (IGC) of quenched highly pure steel Fe-20% Cr-20Ni in boiling solution 27% HNO_3+40 g/l Cr"6"+, as well as in sulphuric and nitric acids mainly at potentials, corresponding to repassivation range, has been studied. It is shown that steel susceptibility to IGC depends on impurity nature and to a high extent is determined by the potential value independent of the way of its achieving. The most unfavourable effect on stability of grain boundaries is produced by microadditions of boron as well as by impurities of phosphorus and silicon. To ensure increased corrosion resistance of the investigated steel against IGC in highly oxidative media the pontent of phosphorus and silicon impurities unit should not exceed 0.01 and 0.2% respectively. At that, boron ...

Energy Technology Data Exchange (ETDEWEB)

The goal of this project is to provide materials engineers, chemical engineers and plant operators with a software tool that will enable them to predict localized corrosion of process equipment including fabricated components as well as base alloys. For design and revamp purposes, the software predicts the occurrence of localized corrosion as a function of environment chemistry and assists the user in selecting the optimum alloy for a given environment. For the operation of existing plants, the software enables the users to predict the remaining life of equipment and help in scheduling maintenance activities. This project combined fundamental understanding of mechanisms of corrosion with focused experimental results to predict the corrosion of advanced, base or fabricated, alloys in real-world environments encountered in the chemical industry. At the heart of this approach is the development of models that predict the ...

Indian Institute of Science Theses & Dissertations (India)

Full Text Available

International Science & Technology Center (ISTC)

Determination of Special Molybdenum Alloys Optimal Structure Using the Cybernetic Method

International Science & Technology Center (ISTC)

Development of the Corrosion Protection Technology for Special Steels and Alloys

International Nuclear Information System (INIS)

The effects of equal #SIGMA#Ai for different combinations of the annealing temperature and annealing time on corrosion resistance and evolution of precipitates of Zircaloy-2 were investigated. Nodular corrosion resistance in the out-of-pile corrosion test was degraded with increasing #SIGMA#Ai only when it was increased by extending the annealing time at 894 K but did not depend on #SIGMA#Ai which was increased by raising the annealing temperature for a constant annealing time of 2.5 h. Extensive observation and micro-analysis of precipitates by analytical electron microscope (AEM) suggested the cause of degradation of nodular corrosion resistance to be the remarkable increase in volume fraction of Si-containing precipitates such as Zr_3Si and Zr_2Si, which were observed more frequently in large #SIGMA#Ai only when it was increased by extending the annealing time at 894 K. On the other hand, uniform corrosion resistance was improved with increasing #SIGMA#Ai irrespective of the ...

Energy Technology Data Exchange (ETDEWEB)

For an assessment of the future US spallation neutron source (SNS) target performance, radiation induced hardening and microstructural evolution were investigated as a function of ion dose for EC316LN stainless steel. Irradiation was carried out using 3.5 MeV Fe{sup +}, 360 keV He{sup +}, and 180 keV H{sup +} simultaneous ion-beams at 200 deg. C to simulate the damage, He and H production in the SNS target vessel wall. At low dose (< 1 dpa), the predominant defects were black dots whose number density saturated rapidly within a few dpa. This was followed by the evolution of interstitial loops whose number density saturated below 15 dpa. Although He-bubbles were not visible, severely scalloped loops suggested that the implanted He/H atoms existed in the form of small clusters. Comparison with reported neutron irradiation data showed that hardening and ductility loss occurred mostly in the black dot regime (< 1 dpa), but that good ductility (>20% ...

International Nuclear Information System (INIS)

Rapid corrosion of PWR steam generator carbon steel support structures and consequential denting of steam generator tubes led to considerable investigation of the mechanism of corrosion and for palliatives. The basic mechanism is now fairly well understood. Chloride present in the boiler feedwater from condenser leakage is concentrated in the support plate crevice as a result of the superheat present. This leads to the formation of a low pH acid ferrous chloride environment either through the hydrolysis of a weak base chloride such as MgCl_2 or the combined action of a neutral chloride with an oxidizing agent. Rapid attack of the carbon steel ensues with the Fe_3O_4 corrosion product forming at the metal/oxide interface. This oxide has a volume approximately twice that of the steel consumed and thus eventually fills the crevice between the tube and the support plate. Oxide growth continues leading to compression of the Alloy 600 primary tube ...

Energy Technology Data Exchange (ETDEWEB)

In the invar alloy (Fe{sub 0.65}Ni{sub 0.35}){sub 1-} {sub x} Mn {sub x} we measured the magnetic form factor s(Q) and the intermediate scattering function s(Q,t) for a sample close to the critical Mn concentration (x {sub c}=0.139), at which the sample turns to a re-entrant spin glass phase. The aim was to check whether the magnetic behaviour would approach the Q-independent relaxation behaviour of a classical spin glass when x=x {sub c}. The experiment showed a quite similar spin freezing as for a more ferromagnetic sample with x=0.113. The intermediate scattering function and the form factor were determined by paramagnetic NSE. The normalized scattering function S(Q,t)=s(Q,t)/s(Q)=exp[(-{gamma}t) {sup n}] was fitted by stretched exponential decay. As a function of temperature T<200 K the inverse time constant {gamma} showed the change of more than four orders of magnitude from frozen spin glass (T=60 K to T=100 K), where the ...

International Nuclear Information System (INIS)

Nitrogen has been added to stainless steels to improve mechanical strength and corrosion resistance. High nitrogen steel production is limited by high gas pressure requirements and low nitrogen solubility in the melt. One way to overcome this limitation is the addition of nitrogen in solid state because of its higher solubility in austenite. However, gas and salt bath nitriding have been done at temperatures around 550 C, where nitrogen solubility in the steel is still very low. High temperature nitriding has been, thus proposed to increase nitrogen contents in the steel but the presence of oxide layers on top of the steel is a barrier to nitrogen intake. In this paper a modified plasma nitriding process is proposed. The first step of this process is a hydrogen plasma sputtering for oxide removal, exposing active steel surface improving nitrogen pickup. This is followed by a nitriding step where high nitrogen contents are introduced in the outermost layer of the steel. Diffusion ...

Energy Technology Data Exchange (ETDEWEB)

Exploratory experiments of laser welding cast Ni-based superalloy K418 turbo disk and alloy steel 42CrMo shaft were conducted. Microstructure of the welded seam was characterized by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive spectrometer (EDS). Mechanical properties of the welded seam were evaluated by microhardness and tensile strength testing. The corresponding mechanisms were discussed in detail. Results showed that the laser-welded seam had non-equilibrium solidified microstructures consisting of FeCr{sub 0.29}Ni{sub 0.16}C{sub 0.06} austenite solid solution dendrites as the dominant and some fine and dispersed Ni{sub 3}Al {gamma}' phase and Laves particles as well as little amount of MC short stick or particle-like carbides distributed in the interdendritic regions. The average microhardness of the welded seam was relatively uniform and lower than that of the base metal ...

International Nuclear Information System (INIS)

Pitting crevice and intergranular corrosion resistances of titanium-modified low-carbon austenitic stainless steel with a nominal composition of 15% Cr, 15% Ni, 0.24% Ti and 2.5% Mo were found superior to conventional type 316 SS. Potentiodynamic anodic polarization studies in a neutral chloride medium (0.5M NaCl solution) and the immersion studies in boiling solution containing (by wt%) 11% H_2SO_4 + 3% HCl + 1% CuCl_2 + 1% FeCl_3 for 24 h showed higher critical pitting and crevice potentials and lower corrosion rate values respectively. The elemental composition across the pit sites was also determined by EPMA analysis. Sensitization studies carried out by following ASTM A262 practices A and E and electrochemical potentiokinetic reactivation (EPR) tests on this alloy heat treated at 923 K for 1 and 50 h showed a better resistance to intergranular corrosion than that for conventional type 316 SS. From the results available, the most likely ...

International Nuclear Information System (INIS)

Experimental results of compatibility tests on ceramics-metal bonded structures performed under high heat flux conditions in splash test apparatus are reported. Emphasis is placed on results of the channel wall design and its critical operating conditions under MHD environment. The module design of one cold type and three semihot type insulators have been tested. These materials were Al_2O_3, Al_2MgO_4, LaAlO_4, MgO and Sialon ceramics. The methods of cold type ceramics-metal bonding structure were studied on Al_2O_3 and Spinel spray coating technology. The refractory metallizing and ceramics-metal graded structure manufactured by HIP technologies were applied to bonding between the MgO or LaAlO_4 and metallic cooling system. The Sialon non-bonding structure was tested with mechanical supported cooling system by shrinc fitting method. The results indicated that the bonding structures made of the MgO(MG-S) with Copper and Fe-Ni Alloy relaxation ...

Science.gov (United States)

... MOLYBDENUM ALLOY GUN BARREL LINERS o0 in ... NEW POWDER TECHNOLOGIES FOR MOLYBDENUM ALLOY GUN BARREL LINERS ...

International Nuclear Information System (INIS)

... filters molybdenum alloys production sulfuric acid alloys chemical reactions ...

International Nuclear Information System (INIS)

Results of hot cracking on welds with compositions between alloy 800 and AWS ER NiCr 3. Investigation of the influence of Si, Mn, Ti and Al on the hot cracking suscpetibility of the alloy 800. (orig.).

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Science.gov (United States)

Not Available

Energy Technology Data Exchange (ETDEWEB)

Alloys are described which contain nickel, aluminum, boron, iron and in some instances manganese, niobium and titanium.

British Library Electronic Table of Contents (United Kingdom)

An operator of FE-closure is introduced on the set of functions of a multivalued logic based on the systems of functional equations. It is proved that, for every k ? 2, the FE-closure operator generates a finite classification on the set P k of functions of k-valued logic. The least class in this classification is shown to be the class H k of all homogeneous functions. Also a series of corollaries are obtained concerning the finite FE-generating sets in the FE-closed classes.

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

KoreaScience (Korea)

Full Text Available

KoreaScience (Korea)

Full Text Available

International Nuclear Information System (INIS)

By using a variational Monte Carlo method, we examine an effective low-energy model for LaFeAsO derived from an ab initio downfolding scheme. We show that quantum and many-body fluctuations near the antiferromagnetic (AF) quantum critical point largely reduce the antiferromagnetic ordered moment. Our derived model not only quantitatively reproduces the small ordered moment in LaFeAsO, but also accounts for the diversity from LaFePO, BaFe_2As_2 to FeTe. Electron correlation is found to determine the observed material dependence. We also find that LaFeAsO is subject to large orbital fluctuations, sandwiched by the AF Mott insulator and weakly correlated metals. The orbital fluctuations and Dirac-cone dispersion hold keys for the diverse magnetic properties. (author)

Energy Technology Data Exchange (ETDEWEB)

Full text: Magnetic multilayer materials are becoming technologically important as they provide a more efficient means of magnetic reading and storage through utilisation of their giant magnetoresistance and oscillatory magnetic coupling. This study presents preliminary tight-binding calculations with a view of developing a consistent tight-binding model of `spin valve` Fe-Cu-Fe tri-layer materials. Further work involves using a self-consistent tight-binding approach to obtain a more accurate picture of this system and a better understanding of surface effects at the Fe-Cu interface 1 fig., 4 refs.

International Nuclear Information System (INIS)

An island of isomers have recently been observed on both sides of the N=40 shell below the Ni isotopes. Isomeric states in the 65Fe and 67Fe allow the knowledge of the single particle structure around the #nu#g9/2 shell. Moreover, the excitation energy of the first 2+ and 4+ states in the 68Fe have been established by #beta#-#gamma# correlation. The evolution of the structure of the Fe isotopes going far away from the valley of stability is, for the first time, given for N>40.

Energy Technology Data Exchange (ETDEWEB)

We present ab-initio calculations of the electronic structure of small Fe clusters (1-9 atoms) on Ni(001), Ni(111), Cu(001) and Cu(111) surfaces. Our focus is on the spin moments and their dependence on cluster size and shape. We derive a simple quantitative rule that relates the moment of each Fe atom linearly to its coordination number. Thus, for an arbitrary Fe cluster the spin moment of the cluster and of the individual Fe atoms can be readily found if the positions of the atoms are known. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Due to the well-establish corrosion problems of Alloy 600 as a steam-generator material and the subsequent focus on thermally treated (TT) Alloy 690 and Alloy 800 as alternative materials, a systematic analysis of the corrosion behavior of these two latter alloys is warranted. Corrosion test results for Alloys 690 TT and 800 were collected and organized in the form of corrosion mode diagrams. Selected data for mill annealed (MA) Alloy 600 were also included for reference. The corrosion mode diagrams correlate the modes of corrosion degradation observed in tests as functions of the environment pH and electrochemical potential (ECP). The diagrams confirm that Alloys 690TT shows some susceptibility in caustic environments, and Alloy 800 shows susceptibility in both caustic and highly acidic environments. (authors). 6 figs., ...

Energy Technology Data Exchange (ETDEWEB)

Here we examine Fe speciation within Fe-encrusted biofilms formed during 2-month seafloor incubations of sulfide mineral assemblages at the Main Endeavor Segment of the Juan de Fuca Ridge. The biofilms were distributed heterogeneously across the surface of the incubated sulfide and composed primarily of particles with a twisted stalk morphology resembling those produced by some aerobic Fe-oxidizing microorganisms. Our objectives were to determine the form of biofilm-associated Fe, and identify the sulfide minerals associated with microbial growth. We used micro-focused synchrotron-radiation X-ray fluorescence mapping (mu XRF), X-ray absorption spectroscopy (mu EXAFS), and X-ray diffraction (mu XRD) in conjunction with focused ion beam (FIB) sectioning, and highresolution transmission electron microscopy (HRTEM). The chemical and mineralogical composition of an Fe-encrusted biofilm ...

Energy Technology Data Exchange (ETDEWEB)

Electronic properties of passive films formed on Fe at various applied potentials in pH 8.5 buffer solution were examined through the photocurrent measurement and impedance spectroscopy. Passive film formed on Fe at relatively low potentials was found to be r-FeOOH layer and internal r-Fe{sub 2}O{sub 3} layer. However, the r-FeOOH layer became unstable and disappeared at potentials below 400mV and hence may be an adsorbed layer. An electronic band structure model for the passive film of Fe was suggested on the basis of the spinel band model with involving two types of electronic excitation processes, i. e., the p-d and the d-d transition together. The effects of applied potential on the photocurrent behaviors of the passive film on Fe were explained appropriately by separating the photocurrent spectra depending on the transition type. The ...

Energy Technology Data Exchange (ETDEWEB)

Fuel cell vehicles have been identified as the personal transportation technology of the future because of their high efficiency and very low emissions. To achieve the goal of road-ready fuel cell vehicles, great strides must be made in the development of fuel cells, hydrogen production and hydrogen storage technologies, that includes metal-H interaction studies and safety considerations. The interaction between two-hydrogen atoms and a {gamma}-Fe structure containing a vacancy has been studied using a cluster model and a theoretical method. For the study of the sequential absorption, the hydrogen atoms were positioned in their energy minima configurations, near the vacancy. The interactions mainly involve Fe 4s-H 1s atomic orbitals. The contribution of Fe 4p and Fe 3d orbitals is much less important. The Fe-Fe bond is weakened as new Fe-H-H and H-H pairs were ...

British Library Electronic Table of Contents (United Kingdom)

We synthesized Fe3O4Gg nanocomposites through a combination of solvothermal, hydrothermal, and chemical redox reactions. Characterization of the resulting samples by X-ray diffraction, Fourier-transform infrared spectroscopy, field-emission scanning and transmission electron microscopy, and magnetic measurement is reported. Compared to Fe3O4g nanocomposites, the Fe3O4Gg nanocomposites showed enhanced antibacterial activity. The Fe3O4Gg nanocomposites were able to almost entirely prevent growth of Escherichia coli when the concentration of Ag nanoparticles was 10mg/mL. Antibacterial activity of the Fe3O4Gg nanocomposites was maintained for more than 40h at 37^oC. The intermediate carbon layer not only protects magnetic core, but also improves the dispersion and antibacterial activity of the...

British Library Electronic Table of Contents (United Kingdom)

Microanalytical methods suitable for the determination of Fe, Cu in HT-29 (human colon adenocarcinoma) cells treated with different iron compounds (Fe(II) sulfate, Fe(III) chloride, Fe(III) citrate and Fe(III) transferrin) and cultured in medium supplemented or not with 10% (v/v) fetal calf serum (FCS) by total reflection X-ray fluorescence spectrometry (TXRF) and simultaneous graphite furnace atomic absorption spectrometry (GF-AAS) were developed. The developed TXRF method was also suitable for Zn determination in the samples. The main advantage of the proposed methods is the execution of all sample preparation steps following incubation and prior to the elemental analysis in the same Eppendorf tubes. Sample preparation was performed at microscale (115mL sample volume) with 65% nitric aci...

CERN Document Server

This paper proposes the use of particle swarm optimization method (PSO) for finite element (FE) model updating. The PSO method is compared to the existing methods that use simulated annealing (SA) or genetic algorithms (GA) for FE model for model updating. The proposed method is tested on an unsymmetrical H-shaped structure. It is observed that the proposed method gives updated natural frequencies the most accurate and followed by those given by an updated model that was obtained using the GA and a full FE model. It is also observed that the proposed method gives updated mode shapes that are best correlated to the measured ones, followed by those given by an updated model that was obtained using the SA and a full FE model. Furthermore, it is observed that the PSO achieves this accuracy at a computational speed that is faster than that by the GA and a full FE model which is faster ...

International Nuclear Information System (INIS)

Consideration is given to the process of the formation of a titanium sponge alloyed with niobium or tantalum, in the joint metallic reduction of titanium, niobium and tantanum chlorides. A percentage composition of the phases observed and the structure of the alloyed sponge have been studied. It is shown that after one remelting operation of the alloyed sponge the alloys of titanium with niobium and tantalum have a uniform component distribution. At the stage of chloride reduction there appear solid solutions based on titanium and an alloying component. The stage of vacuum separation of the reaction mass is associated with a mutual dissolution of the primary phases and the formation of the solid solutions of the alloyed titanium sponge, which, by their composition, are close to the desired alloy composition. The principal features of the ...

International Nuclear Information System (INIS)

The following methods of quartz ceramics alloying were considered: alloying of initial quartz glass; introduction of alloying additive into water slip of quartz glass; porous materials impregnation with salt aqueous solutions and subsequent salt thermal decomposition with formation of stable oxides in pores of ceramics. Oxygen free compounds BN, SiB_4, SiC, Si_3N_4, REM oxides and transition metal oxides were used as alloying additives. Main properties of the materials and compositions obtained are presented.

Energy Technology Data Exchange (ETDEWEB)

The processing characteristics, tensile properties, and oxidation response of two Nb-Ti-Al-Cr alloys were investigated. One creep tests at 650{degrees}C and 172 MPa was conducted on the base alloy which contained 40Nb-40-Ti-10Al-10Cr. A second alloy was modified with 0.11 at. % carbon and 0.07 at. % yttrium. Alloys were arc melted in a chamber backfilled with argon, drop cast into a water-cooled copper mold, and cold rolled to obtain a 0.8-mm sheet. The sheet was annealed at 1100{degrees}C for 0.5 h. Longitudinal tensile specimens and oxidation specimens were obtained for both the base alloy and the modified alloy. Tensile properties were obtained for the base alloy at room temperature, 400, 600, 700, 800, 900, and 1000{degrees}C, and for the modified alloy at room temperature, 400, 600, 700, and 800{degrees}C. Oxidation ...

International Nuclear Information System (INIS)

Investigated are the characteristics of high-temperature plastic deformation the velocity sensitivity of flow stresses, deformation curves, flow stresses, deformation before rupture - as well as the structure of beryllium alloys containing nickel (0.5-4 %), yttrium (0.5-2 %) and aluminium (38 %). The alloys containing nickel (2%) and yttrium (0.5 %) are superplastic, however, deformation before fracture of the alloys is lower than that of the unalloyed beryllium. The singularities of high-temperature plastic flow of the alloys and the causes of deterioration of their plasticity are determined.

Energy Technology Data Exchange (ETDEWEB)

Since 1991, secondary side cracking has become a major concern in EDF steam generators. At 350 C, IGSCC of Alloy 600 was found in pure NaOH solutions from 4 to 500 g/l, with a maximum at 100 g/l. From the present results and available data, IGSCC of Alloy 690 occurred in pure NaOH solutions from 40 to 500 g/l, but the greatest sensitivity was observed at 100 g/l. TG/IGSCC of Alloy 800 became more severe with increasing NaOH solutions, from 10 to 500 g/l. On the whole, the ranking for SCC-resistance was Alloy 600 < Alloy 800 < Alloy 690. A significant improvement was still obtained with 690TT with intergranular carbides (industrial tubes) and perhaps with Alloy 800 NG (nuclear grade), but both alloys cracked at the highest stresses. IGSCC susceptibility of Alloy 600 MA was higher for the tubes ...

International Nuclear Information System (INIS)

The Wendelstein 7-X (W7-X) modular stellarator is under construction at the Max-Planck-Institut fuer Plasmaphysik in Greifswald, Germany. The W7-X magnet system contains 70 coils made up from helium cooled superconducting cables in aluminium alloy (EN AW-6063) jackets. Several hundred connections of the jacket to the cable joints are made by aluminium-to-aluminium welds. Due to geometrical and thermal boundary conditions these welds cannot be accomplished free from defects. Microscopic analyses of the welds show that a variety of small flaws such as cracks and pores develop during welding. The welds have thus to be dimensioned accordingly, and appropriate weld qualification, investigation and testing has to be done in order not to jeopardise the structural integrity and leak tightness. The weld is mechanically loaded during cool-down due to the difference in thermal contractions between the GRP insulation and the aluminium, and during operation by bending moments ...

Energy Technology Data Exchange (ETDEWEB)

Experiments of autogenous laser full penetration welding between dissimilar cast Ni-based superalloy K418 and alloy steel 42CrMo flat plates with 3.5 mm thickness were conducted using a 3 kW continuous wave (CW) Nd:YAG laser. The influences of laser welding velocity, flow rate of side-blow shielding gas, defocusing distance were investigated. Microstructure of the welded seam was characterized by optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD) and energy dispersive spectrometer (EDS). Mechanical properties of the welded seam were evaluated by microhardness and tensile strength testing. Results show that high quality full penetration laser-welded joint can be obtained by optimizing the welding velocity, flow rate of shielding gas and defocusing distance. The laser-welded seam have non-equilibrium solidified microstructures consisting of {gamma}-FeCr{sub 0.29}Ni{sub 0.16}C{sub 0.06} austenite solid solution ...

Science.gov (United States)

Experiments of autogenous laser full penetration welding between dissimilar cast Ni-based superalloy K418 and alloy steel 42CrMo flat plates with 3.5 mm thickness were conducted using a 3 kW continuous wave (CW) Nd:YAG laser. The influences of laser welding velocity, flow rate of side-blow shielding gas, defocusing distance were investigated. Microstructure of the welded seam was characterized by optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD) and energy dispersive spectrometer (EDS). Mechanical properties of the welded seam were evaluated by microhardness and tensile strength testing. Results show that high quality full penetration laser-welded joint can be obtained by optimizing the welding velocity, flow rate of shielding gas and defocusing distance. The laser-welded seam have non-equilibrium solidified microstructures consisting of ?-FeCr0.29Ni0.16C0.06 austenite solid solution dendrites as the ...

Energy Technology Data Exchange (ETDEWEB)

Three model boilers, manufactured to simulate full-size tube sheet crevices, were tested with various secondary side environments. The first was faulted with organics representative of the decomposition of humic acid. The second was faulted with sodium carbonate and sodium hydroxide, while the third was faulted with sodium sulfate and sodium hydroxide. Each model contained seven tubes, which included Alloy 600 in the mill-annealed (MA) and thermally-treated (TT) conditions and Alloy 690 in the thermally-treated condition. Two models contained Alloy 800 tubes in the mill-annealed condition and one had Alloy 800 in the mill-annealed/cold-worked/glass-bead-peened condition. Two different sizes of tubesheet crevices were used in all model boilers. In the organics-faulted boiler, tubes of Alloy 600MA, Alloy 690TT and Alloy 800MA experienced no ...

UK PubMed Central (United Kingdom)

Rhizosphere acidification by Fe-deficient bean (Phaseolus vulgaris L.) plants was induced by trace amounts of divalent metal ions (Zn, Mn). The induction of this Fe-efficiency reaction...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Susceptibility data of freshly precipitated nitroprussides TM[Fe(CN){sub 5}NO] n H{sub 2}O (TM=Mn, Fe, Co, Ni, Cu) follow very well modified Curie-Weiss law down to T=5 K indicating paramagnetic state; nitroprusside (NP) containing Zn is diamagnetic with a sign of paramagnetic contribution. Deviation from Curie-Weiss law and magnetization measurements on MnNP, FeNP and CoNP below T=5 K can indicate ferrimagnetic ordering at low temperatures. A hysteresis behaviour in ZFC and FC magnetisation with the temperature of bifurcation T{sub b}=6 K was found for CoNP and FeNP. Moessbauer spectra taken at room temperature (besides FeNP) consist of a single symmetric quadrupole-split doublet with parameters {delta} and {delta} typical for Fe{sup II} ions in octahedral sites. A more complicated spectrum of FeNP is a consequence of different ...

UK PubMed Central (United Kingdom)

Under anaerobic conditions, several species of green algae perform a light-dependent hydrogen production catalyzed by a special group of [FeFe] hydrogenases termed HydA. Although highly interesting...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

AZ31 and experimental ZMA611 alloys were strip cast into 2 mm thick strips. The as-cast AZ31 alloy strip consists of columnar dendrites. On the other hand, as-cast ZMA611 alloy strip shows equiaxed dendritic structure through the thickness of strip. These alloys were subjected to various thermomechanical treatments and their tensile properties were evaluated. Strip cast AZ31 alloy in H24 condition has equivalent yield and tensile strengths with similar ductility compared to commercial ingot cast AZ31-H24 alloy, indicating that strip casting is a viable process for the fabrication of Mg alloy strips. The ZMA611 alloy has a large volume fraction of fine dispersoid particles in the microstructure, resulting from the beneficial effect of strip casting on microstructural refinement. It has been shown that the ZMA611 ...

KoreaScience (Korea)

Full Text Available

KoreaScience (Korea)

Full Text Available

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Laser surface alloying with gaseous nitrogen was utilized to improve the wear resistance of a Ti-6Al-4V alloy. Wear-resistant composite coatings reinforced by hard TiN dendrites were produced 'in-situ' on a substrate of a Ti-6Al-4V alloy. The hardness and wear resistance of the laser alloyed coating under two-body abrasive and block-on-ring full-sliding wear conditions were significantly enhanced. (orig.)

International Nuclear Information System (INIS)

Corrosion testings of model alloys, corresponding by chemical composition to simple and complex-alloyed #gamma#- and #gamma#'-phases of nickel heat-resistant alloys are conducted in sodium sulfate and chloride melts. It is ascertained that heat resistant nickel alloys containing over 50 % of hardening #gamma#'-phase, are subject to disastrous sulfide corrosion (SC). Resistance against SC alloys containing below 50 % of #gamma#'-phase is determined by the resistance of #gamma#-solid solution. 10 refs., 3 figs., 2 tabs.

International Nuclear Information System (INIS)

The distribution of mass, charge and angular momentum transfer among the products of 54-Fe (255 MeV) ions collisions with the 106 Cd target have been studied. The energy level schemes for 92-Mo, 60-Ni, 96-Ru and 56-Fe are presented. The production yields of different isotopes were also measured. 1 ref., 14 figs.

International Nuclear Information System (INIS)

We studied the epitaxial growth of iron silicide (#epsilon#-FeSi,#beta#-FeSi_2, and #alpha#-FeSi_2) nanodots on Si (111) substrates by Fe deposition on Si nanodots on Si (111) substrates with ultrathin Si oxide films using reflection high-energy electron diffraction, scanning tunneling microscopy, and transmission electron microscope (TEM). We formed almost single phase iron silicide nanodots by controlling the Fe deposition conditions; growth temperature, deposition rate, and amount. The #epsilon#-FeSi or #alpha#-FeSi_2 nanodots were epitaxially grown in a dome shape with an average size of #approx#5 nm and an ultrahigh density (>10"1"2 cm"-"2) on the surface. We formed #approx#2-nm high and #approx#8-nm wide #beta#-FeSi_2 nanodots in a dome shape with a density of #approx#5x10"1"1 cm"-"2 on the surface. Cross-sectional TEM images ...

Science.gov (United States)

... Accession Number : ADD151811. Title : Ultra High Strength Beta Titanium Alloy for Fasteners. Descriptive Note : Journal article,. ...

Science.gov (United States)

Hilled Bend Spechene of an Alpha-Beta Titanium Alloy. Ti-6M14V. ..... The all beta titanium alloy was nllled from both sides; only the edges were taped. ...

Energy Technology Data Exchange (ETDEWEB)

Four low activation alloy classes, two austenitic and two ferritic, have been incorporated into the MOTA-1B experiment in the FFTF reactor to provide an early assessment of the suitability of such alloys for reactor service.

International Nuclear Information System (INIS)

The effect of various hydrogen concentrations on the crystal lattice period and the hardness of titanium alloy was examined, the alloy containing about 16 at.% Mo (27.5 wt. % Mo) and having #beta# structure. The peculiar features of the mechanism of plastic deformation of the alloy were studied after adding hydrogen to it. A dependence of the crystal lattice period on the concentration of hydrogen was obtained for TixMoxH_2 alloy. It has been established that the hardness of the Ti-Mo alloy does not change when hydrogen is added to it. The presence of hydrogen introduces changes into the mechanism of deformation of #beta#-titanium alloy. The configuration of the inverse pole figures after rolling proves that the transverse slip process in an alloy with hydrogen is hampered, and that the coplanar slip process is developing in it.

Science.gov (United States)

... CLOSURE DURING HOT WORKING OF AN ALPHA/BETA TITANIUM ALLOY (PREPRINT) ... HOT WORKING OF AN ALPHA/BETA TITANIUM ALLOY ...

Energy Technology Data Exchange (ETDEWEB)

In this project, graphite is used as a substitute for lead in order to maintain the machinability of plumbing components at the level of leaded brass. Graphite dispersed in Cu alloy was observed to impart good machinability and reduce the sizes of chips during machining of plumbing components in a manner similar to lead. Copper alloys containing dispersed graphite particles could be successfully cast in several plumbing fixtures which exhibited acceptable corrosion rate, solderability, platability, and pressure tightness. The power consumption for machining of composites was also lower than that of the matrix alloy. In addition, centrifugally cast copper alloy cylinders containing graphite particles were successfully made. These cylinders can therefore be used for bearing applications, as substitutes for lead-containing copper alloys. The results indicate that copper graphite ...

Science.gov (United States)

... Accession Number : ADD144314. Title : Beta-21S: A High Temperature Metastable Beta Titanium Alloy. Descriptive Note : Conference Proceedings, ...

Energy Technology Data Exchange (ETDEWEB)

Whereas supersaturated aluminum alloys demonstrate enhanced passivity, conventional aluminum alloys spontaneously pit in air-saturated chloride solutions. We have concentrated on three areas: evaluation and characterization of Al-W alloys, which exhibit the best corrosion performance of any alloy system studied to date; characterization of the passive-film structure of Al-Mo alloys; and production and characterization of Al-W and Al-Ta powders, which will be used for compaction into bulk material. Surface analysis of the Al-W passive films formed during polarization show surprising little oxidized solute compared to other alloys. These results indicate that the barrier layer formation and electrostatic repulsion mechanisms used to explain the passivity of other alloys are not involved here. Instead the W may act to stabilize the passive film ...

British Library Electronic Table of Contents (United Kingdom)

Fe-doped TiO2 hollow spheres (Fe-THs) were synthesized by sol?gel process using carbon spheres as templates. The prepared samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV?vis diffuse reflectance spectrum (DRS), N2 adsorption?desorption isotherms, Electron paramagnetic resonance (EPR) spectroscopy and Photoluminescence emission spectroscopy (PL). UV?vis spectra showed that Fe3+ doping could extend the absorption edge to the visible region. EPR spectra showed that Fe3+ was incorporated into the crystal lattice of TiO2, which could inhibit the recombination of photo-induced electron?hole pairs and improve the photocatalytic activity. The photocatalytic activities of the prepared samples were evaluated for the degradation of dye Reactive Brillia...

CERN Document Server

We present constraints on theoretical models of Type Ia SNe using spatially resolved ASCA X-ray spectroscopy of four galaxy clusters: Abell 496, Abell 2199, Abell 3571 & Perseus. All four clusters have central Fe abundance enhancements and an ensemble of abundance ratios are used to show that most of the Fe in the central regions of the clusters comes from SN Ia. At the center of each cluster, simultaneous analysis of spectra from all ASCA instruments shows that the Ni to Fe abundance ratio (normalized by the solar ratio) is ~ 4. We use the Ni/Fe ratio as a discriminator between SN Ia explosion models: the Ni/Fe ratio of ejecta from the "Convective Deflagration" model W7 is consistent with the observations, while those of "delayed detonation" models are not consistent at the 90% confidence level.

International Nuclear Information System (INIS)

In-reactor testing of bolt-loaded compact tension specimens was performed in 360 C water to determine the irradiation-assisted stress corrosion cracking (IASCC) behavior of HTH Alloy X-750 and direct-aged Alloy 625. New data confirm previous results showing that high irradiation levels reduce SCC resistance in Alloy X-750. Heat-to-heat variability correlates with boron content, with low boron heats showing improved IASCC properties. Alloy 625 is resistant to IASCC, as no cracking was observed in any Alloy 625 specimens. Microstructural, microchemical and deformation studies were performed to characterize the mechanisms responsible for IASCC in Alloy X-750 and the lack of an effect in Alloy 625. The mechanisms under investigation are: boron transmutation effects, radiation-induced changes in microstructure and deformation characteristics, and ...

Energy Technology Data Exchange (ETDEWEB)

The CALPHAD (calculations of phase diagrams) method is used to examine the effects of applied magnetic fields on the {alpha}/{gamma} phase boundary in the Fe-Si system in the paramagnetic state. The reported susceptibility data for pure Fe is first re-evaluated. The contributions to the total Gibbs energy of the ferrite ({alpha}) and austenite ({gamma}) from the external fields are calculated based on the Curie-Weiss law and the re-evaluated susceptibility data. The Fe-Si phase diagram on the Fe-rich side as a function of applied field is calculated using the Thermo-Calc(TM) package. With increasing field strength, the {gamma} loop shrinks monotonically; that is, the {alpha}/{gamma}-Fe transition temperature increases while that for {gamma}/{delta}-Fe transition decreases, albeit more slowly. Finally, in conformance with the existing CALPHAD databank, ...

International Nuclear Information System (INIS)

The effect of the nitrogen uptake in #alpha#-iron upon spark erosion in gaseous and liquid ammonia, plasma nitriding, and plasma immersion ion implantation is studied. The resulting phases and hyperfine parameters, measured by the Moessbauer spectroscopy, are discussed from the point of view of initial conditions of their preparation and subsequent heat and/or mechanical treatment. Spark erosion in the ammonia gas produces fine particles with the dominating ferromagnetic #alpha#-Fe phase (50%). The 20% of specimen volume form #alpha#'-Fe and #alpha#''-Fe_1_6N_2 phases. The last 30% occupy the #gamma#'-Fe_4N, ferro- and paramagnetic #epsilon# phases, and #gamma#-Fe(N). Nitriding in the liquid ammonia allows to incorporate the higher content of nitrogen into #alpha#-iron particles which results in the formation of paramagnetic #epsilon#(#zeta#)-Fe_2N phase. This ...

KoreaScience (Korea)

Full Text Available

International Nuclear Information System (INIS)

The investigations carried out on Alloy 800 in aqueous high-temperature environments in France as well as in other countries are reviewed. These studies are mainly concerned with nuclear industry where Alloy 800 can be used as structural material for steam generators of PWR, breeders or HTR. As results referred to in the literature on cracking in caustic environmens do not always agree, a discussion is presented on the matter. The behaviour of Alloy 800 in superheated steam is examined. (Auth.).

International Nuclear Information System (INIS)

(Nov 1973). United States Greenfield, MA Pierce, CM Chicago, IL.